Loading...
1/*
2 * kernel/sched/core.c
3 *
4 * Kernel scheduler and related syscalls
5 *
6 * Copyright (C) 1991-2002 Linus Torvalds
7 *
8 * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and
9 * make semaphores SMP safe
10 * 1998-11-19 Implemented schedule_timeout() and related stuff
11 * by Andrea Arcangeli
12 * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar:
13 * hybrid priority-list and round-robin design with
14 * an array-switch method of distributing timeslices
15 * and per-CPU runqueues. Cleanups and useful suggestions
16 * by Davide Libenzi, preemptible kernel bits by Robert Love.
17 * 2003-09-03 Interactivity tuning by Con Kolivas.
18 * 2004-04-02 Scheduler domains code by Nick Piggin
19 * 2007-04-15 Work begun on replacing all interactivity tuning with a
20 * fair scheduling design by Con Kolivas.
21 * 2007-05-05 Load balancing (smp-nice) and other improvements
22 * by Peter Williams
23 * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith
24 * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri
25 * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins,
26 * Thomas Gleixner, Mike Kravetz
27 */
28
29#include <linux/kasan.h>
30#include <linux/mm.h>
31#include <linux/module.h>
32#include <linux/nmi.h>
33#include <linux/init.h>
34#include <linux/uaccess.h>
35#include <linux/highmem.h>
36#include <asm/mmu_context.h>
37#include <linux/interrupt.h>
38#include <linux/capability.h>
39#include <linux/completion.h>
40#include <linux/kernel_stat.h>
41#include <linux/debug_locks.h>
42#include <linux/perf_event.h>
43#include <linux/security.h>
44#include <linux/notifier.h>
45#include <linux/profile.h>
46#include <linux/freezer.h>
47#include <linux/vmalloc.h>
48#include <linux/blkdev.h>
49#include <linux/delay.h>
50#include <linux/pid_namespace.h>
51#include <linux/smp.h>
52#include <linux/threads.h>
53#include <linux/timer.h>
54#include <linux/rcupdate.h>
55#include <linux/cpu.h>
56#include <linux/cpuset.h>
57#include <linux/percpu.h>
58#include <linux/proc_fs.h>
59#include <linux/seq_file.h>
60#include <linux/sysctl.h>
61#include <linux/syscalls.h>
62#include <linux/times.h>
63#include <linux/tsacct_kern.h>
64#include <linux/kprobes.h>
65#include <linux/delayacct.h>
66#include <linux/unistd.h>
67#include <linux/pagemap.h>
68#include <linux/hrtimer.h>
69#include <linux/tick.h>
70#include <linux/ctype.h>
71#include <linux/ftrace.h>
72#include <linux/slab.h>
73#include <linux/init_task.h>
74#include <linux/context_tracking.h>
75#include <linux/compiler.h>
76#include <linux/frame.h>
77
78#include <asm/switch_to.h>
79#include <asm/tlb.h>
80#include <asm/irq_regs.h>
81#include <asm/mutex.h>
82#ifdef CONFIG_PARAVIRT
83#include <asm/paravirt.h>
84#endif
85
86#include "sched.h"
87#include "../workqueue_internal.h"
88#include "../smpboot.h"
89
90#define CREATE_TRACE_POINTS
91#include <trace/events/sched.h>
92
93DEFINE_MUTEX(sched_domains_mutex);
94DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
95
96static void update_rq_clock_task(struct rq *rq, s64 delta);
97
98void update_rq_clock(struct rq *rq)
99{
100 s64 delta;
101
102 lockdep_assert_held(&rq->lock);
103
104 if (rq->clock_skip_update & RQCF_ACT_SKIP)
105 return;
106
107 delta = sched_clock_cpu(cpu_of(rq)) - rq->clock;
108 if (delta < 0)
109 return;
110 rq->clock += delta;
111 update_rq_clock_task(rq, delta);
112}
113
114/*
115 * Debugging: various feature bits
116 */
117
118#define SCHED_FEAT(name, enabled) \
119 (1UL << __SCHED_FEAT_##name) * enabled |
120
121const_debug unsigned int sysctl_sched_features =
122#include "features.h"
123 0;
124
125#undef SCHED_FEAT
126
127/*
128 * Number of tasks to iterate in a single balance run.
129 * Limited because this is done with IRQs disabled.
130 */
131const_debug unsigned int sysctl_sched_nr_migrate = 32;
132
133/*
134 * period over which we average the RT time consumption, measured
135 * in ms.
136 *
137 * default: 1s
138 */
139const_debug unsigned int sysctl_sched_time_avg = MSEC_PER_SEC;
140
141/*
142 * period over which we measure -rt task cpu usage in us.
143 * default: 1s
144 */
145unsigned int sysctl_sched_rt_period = 1000000;
146
147__read_mostly int scheduler_running;
148
149/*
150 * part of the period that we allow rt tasks to run in us.
151 * default: 0.95s
152 */
153int sysctl_sched_rt_runtime = 950000;
154
155/* cpus with isolated domains */
156cpumask_var_t cpu_isolated_map;
157
158/*
159 * this_rq_lock - lock this runqueue and disable interrupts.
160 */
161static struct rq *this_rq_lock(void)
162 __acquires(rq->lock)
163{
164 struct rq *rq;
165
166 local_irq_disable();
167 rq = this_rq();
168 raw_spin_lock(&rq->lock);
169
170 return rq;
171}
172
173#ifdef CONFIG_SCHED_HRTICK
174/*
175 * Use HR-timers to deliver accurate preemption points.
176 */
177
178static void hrtick_clear(struct rq *rq)
179{
180 if (hrtimer_active(&rq->hrtick_timer))
181 hrtimer_cancel(&rq->hrtick_timer);
182}
183
184/*
185 * High-resolution timer tick.
186 * Runs from hardirq context with interrupts disabled.
187 */
188static enum hrtimer_restart hrtick(struct hrtimer *timer)
189{
190 struct rq *rq = container_of(timer, struct rq, hrtick_timer);
191
192 WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
193
194 raw_spin_lock(&rq->lock);
195 update_rq_clock(rq);
196 rq->curr->sched_class->task_tick(rq, rq->curr, 1);
197 raw_spin_unlock(&rq->lock);
198
199 return HRTIMER_NORESTART;
200}
201
202#ifdef CONFIG_SMP
203
204static void __hrtick_restart(struct rq *rq)
205{
206 struct hrtimer *timer = &rq->hrtick_timer;
207
208 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
209}
210
211/*
212 * called from hardirq (IPI) context
213 */
214static void __hrtick_start(void *arg)
215{
216 struct rq *rq = arg;
217
218 raw_spin_lock(&rq->lock);
219 __hrtick_restart(rq);
220 rq->hrtick_csd_pending = 0;
221 raw_spin_unlock(&rq->lock);
222}
223
224/*
225 * Called to set the hrtick timer state.
226 *
227 * called with rq->lock held and irqs disabled
228 */
229void hrtick_start(struct rq *rq, u64 delay)
230{
231 struct hrtimer *timer = &rq->hrtick_timer;
232 ktime_t time;
233 s64 delta;
234
235 /*
236 * Don't schedule slices shorter than 10000ns, that just
237 * doesn't make sense and can cause timer DoS.
238 */
239 delta = max_t(s64, delay, 10000LL);
240 time = ktime_add_ns(timer->base->get_time(), delta);
241
242 hrtimer_set_expires(timer, time);
243
244 if (rq == this_rq()) {
245 __hrtick_restart(rq);
246 } else if (!rq->hrtick_csd_pending) {
247 smp_call_function_single_async(cpu_of(rq), &rq->hrtick_csd);
248 rq->hrtick_csd_pending = 1;
249 }
250}
251
252static int
253hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu)
254{
255 int cpu = (int)(long)hcpu;
256
257 switch (action) {
258 case CPU_UP_CANCELED:
259 case CPU_UP_CANCELED_FROZEN:
260 case CPU_DOWN_PREPARE:
261 case CPU_DOWN_PREPARE_FROZEN:
262 case CPU_DEAD:
263 case CPU_DEAD_FROZEN:
264 hrtick_clear(cpu_rq(cpu));
265 return NOTIFY_OK;
266 }
267
268 return NOTIFY_DONE;
269}
270
271static __init void init_hrtick(void)
272{
273 hotcpu_notifier(hotplug_hrtick, 0);
274}
275#else
276/*
277 * Called to set the hrtick timer state.
278 *
279 * called with rq->lock held and irqs disabled
280 */
281void hrtick_start(struct rq *rq, u64 delay)
282{
283 /*
284 * Don't schedule slices shorter than 10000ns, that just
285 * doesn't make sense. Rely on vruntime for fairness.
286 */
287 delay = max_t(u64, delay, 10000LL);
288 hrtimer_start(&rq->hrtick_timer, ns_to_ktime(delay),
289 HRTIMER_MODE_REL_PINNED);
290}
291
292static inline void init_hrtick(void)
293{
294}
295#endif /* CONFIG_SMP */
296
297static void init_rq_hrtick(struct rq *rq)
298{
299#ifdef CONFIG_SMP
300 rq->hrtick_csd_pending = 0;
301
302 rq->hrtick_csd.flags = 0;
303 rq->hrtick_csd.func = __hrtick_start;
304 rq->hrtick_csd.info = rq;
305#endif
306
307 hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
308 rq->hrtick_timer.function = hrtick;
309}
310#else /* CONFIG_SCHED_HRTICK */
311static inline void hrtick_clear(struct rq *rq)
312{
313}
314
315static inline void init_rq_hrtick(struct rq *rq)
316{
317}
318
319static inline void init_hrtick(void)
320{
321}
322#endif /* CONFIG_SCHED_HRTICK */
323
324/*
325 * cmpxchg based fetch_or, macro so it works for different integer types
326 */
327#define fetch_or(ptr, mask) \
328 ({ \
329 typeof(ptr) _ptr = (ptr); \
330 typeof(mask) _mask = (mask); \
331 typeof(*_ptr) _old, _val = *_ptr; \
332 \
333 for (;;) { \
334 _old = cmpxchg(_ptr, _val, _val | _mask); \
335 if (_old == _val) \
336 break; \
337 _val = _old; \
338 } \
339 _old; \
340})
341
342#if defined(CONFIG_SMP) && defined(TIF_POLLING_NRFLAG)
343/*
344 * Atomically set TIF_NEED_RESCHED and test for TIF_POLLING_NRFLAG,
345 * this avoids any races wrt polling state changes and thereby avoids
346 * spurious IPIs.
347 */
348static bool set_nr_and_not_polling(struct task_struct *p)
349{
350 struct thread_info *ti = task_thread_info(p);
351 return !(fetch_or(&ti->flags, _TIF_NEED_RESCHED) & _TIF_POLLING_NRFLAG);
352}
353
354/*
355 * Atomically set TIF_NEED_RESCHED if TIF_POLLING_NRFLAG is set.
356 *
357 * If this returns true, then the idle task promises to call
358 * sched_ttwu_pending() and reschedule soon.
359 */
360static bool set_nr_if_polling(struct task_struct *p)
361{
362 struct thread_info *ti = task_thread_info(p);
363 typeof(ti->flags) old, val = READ_ONCE(ti->flags);
364
365 for (;;) {
366 if (!(val & _TIF_POLLING_NRFLAG))
367 return false;
368 if (val & _TIF_NEED_RESCHED)
369 return true;
370 old = cmpxchg(&ti->flags, val, val | _TIF_NEED_RESCHED);
371 if (old == val)
372 break;
373 val = old;
374 }
375 return true;
376}
377
378#else
379static bool set_nr_and_not_polling(struct task_struct *p)
380{
381 set_tsk_need_resched(p);
382 return true;
383}
384
385#ifdef CONFIG_SMP
386static bool set_nr_if_polling(struct task_struct *p)
387{
388 return false;
389}
390#endif
391#endif
392
393void wake_q_add(struct wake_q_head *head, struct task_struct *task)
394{
395 struct wake_q_node *node = &task->wake_q;
396
397 /*
398 * Atomically grab the task, if ->wake_q is !nil already it means
399 * its already queued (either by us or someone else) and will get the
400 * wakeup due to that.
401 *
402 * This cmpxchg() implies a full barrier, which pairs with the write
403 * barrier implied by the wakeup in wake_up_list().
404 */
405 if (cmpxchg(&node->next, NULL, WAKE_Q_TAIL))
406 return;
407
408 get_task_struct(task);
409
410 /*
411 * The head is context local, there can be no concurrency.
412 */
413 *head->lastp = node;
414 head->lastp = &node->next;
415}
416
417void wake_up_q(struct wake_q_head *head)
418{
419 struct wake_q_node *node = head->first;
420
421 while (node != WAKE_Q_TAIL) {
422 struct task_struct *task;
423
424 task = container_of(node, struct task_struct, wake_q);
425 BUG_ON(!task);
426 /* task can safely be re-inserted now */
427 node = node->next;
428 task->wake_q.next = NULL;
429
430 /*
431 * wake_up_process() implies a wmb() to pair with the queueing
432 * in wake_q_add() so as not to miss wakeups.
433 */
434 wake_up_process(task);
435 put_task_struct(task);
436 }
437}
438
439/*
440 * resched_curr - mark rq's current task 'to be rescheduled now'.
441 *
442 * On UP this means the setting of the need_resched flag, on SMP it
443 * might also involve a cross-CPU call to trigger the scheduler on
444 * the target CPU.
445 */
446void resched_curr(struct rq *rq)
447{
448 struct task_struct *curr = rq->curr;
449 int cpu;
450
451 lockdep_assert_held(&rq->lock);
452
453 if (test_tsk_need_resched(curr))
454 return;
455
456 cpu = cpu_of(rq);
457
458 if (cpu == smp_processor_id()) {
459 set_tsk_need_resched(curr);
460 set_preempt_need_resched();
461 return;
462 }
463
464 if (set_nr_and_not_polling(curr))
465 smp_send_reschedule(cpu);
466 else
467 trace_sched_wake_idle_without_ipi(cpu);
468}
469
470void resched_cpu(int cpu)
471{
472 struct rq *rq = cpu_rq(cpu);
473 unsigned long flags;
474
475 if (!raw_spin_trylock_irqsave(&rq->lock, flags))
476 return;
477 resched_curr(rq);
478 raw_spin_unlock_irqrestore(&rq->lock, flags);
479}
480
481#ifdef CONFIG_SMP
482#ifdef CONFIG_NO_HZ_COMMON
483/*
484 * In the semi idle case, use the nearest busy cpu for migrating timers
485 * from an idle cpu. This is good for power-savings.
486 *
487 * We don't do similar optimization for completely idle system, as
488 * selecting an idle cpu will add more delays to the timers than intended
489 * (as that cpu's timer base may not be uptodate wrt jiffies etc).
490 */
491int get_nohz_timer_target(void)
492{
493 int i, cpu = smp_processor_id();
494 struct sched_domain *sd;
495
496 if (!idle_cpu(cpu) && is_housekeeping_cpu(cpu))
497 return cpu;
498
499 rcu_read_lock();
500 for_each_domain(cpu, sd) {
501 for_each_cpu(i, sched_domain_span(sd)) {
502 if (!idle_cpu(i) && is_housekeeping_cpu(cpu)) {
503 cpu = i;
504 goto unlock;
505 }
506 }
507 }
508
509 if (!is_housekeeping_cpu(cpu))
510 cpu = housekeeping_any_cpu();
511unlock:
512 rcu_read_unlock();
513 return cpu;
514}
515/*
516 * When add_timer_on() enqueues a timer into the timer wheel of an
517 * idle CPU then this timer might expire before the next timer event
518 * which is scheduled to wake up that CPU. In case of a completely
519 * idle system the next event might even be infinite time into the
520 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
521 * leaves the inner idle loop so the newly added timer is taken into
522 * account when the CPU goes back to idle and evaluates the timer
523 * wheel for the next timer event.
524 */
525static void wake_up_idle_cpu(int cpu)
526{
527 struct rq *rq = cpu_rq(cpu);
528
529 if (cpu == smp_processor_id())
530 return;
531
532 if (set_nr_and_not_polling(rq->idle))
533 smp_send_reschedule(cpu);
534 else
535 trace_sched_wake_idle_without_ipi(cpu);
536}
537
538static bool wake_up_full_nohz_cpu(int cpu)
539{
540 /*
541 * We just need the target to call irq_exit() and re-evaluate
542 * the next tick. The nohz full kick at least implies that.
543 * If needed we can still optimize that later with an
544 * empty IRQ.
545 */
546 if (tick_nohz_full_cpu(cpu)) {
547 if (cpu != smp_processor_id() ||
548 tick_nohz_tick_stopped())
549 tick_nohz_full_kick_cpu(cpu);
550 return true;
551 }
552
553 return false;
554}
555
556void wake_up_nohz_cpu(int cpu)
557{
558 if (!wake_up_full_nohz_cpu(cpu))
559 wake_up_idle_cpu(cpu);
560}
561
562static inline bool got_nohz_idle_kick(void)
563{
564 int cpu = smp_processor_id();
565
566 if (!test_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu)))
567 return false;
568
569 if (idle_cpu(cpu) && !need_resched())
570 return true;
571
572 /*
573 * We can't run Idle Load Balance on this CPU for this time so we
574 * cancel it and clear NOHZ_BALANCE_KICK
575 */
576 clear_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu));
577 return false;
578}
579
580#else /* CONFIG_NO_HZ_COMMON */
581
582static inline bool got_nohz_idle_kick(void)
583{
584 return false;
585}
586
587#endif /* CONFIG_NO_HZ_COMMON */
588
589#ifdef CONFIG_NO_HZ_FULL
590bool sched_can_stop_tick(struct rq *rq)
591{
592 int fifo_nr_running;
593
594 /* Deadline tasks, even if single, need the tick */
595 if (rq->dl.dl_nr_running)
596 return false;
597
598 /*
599 * If there are more than one RR tasks, we need the tick to effect the
600 * actual RR behaviour.
601 */
602 if (rq->rt.rr_nr_running) {
603 if (rq->rt.rr_nr_running == 1)
604 return true;
605 else
606 return false;
607 }
608
609 /*
610 * If there's no RR tasks, but FIFO tasks, we can skip the tick, no
611 * forced preemption between FIFO tasks.
612 */
613 fifo_nr_running = rq->rt.rt_nr_running - rq->rt.rr_nr_running;
614 if (fifo_nr_running)
615 return true;
616
617 /*
618 * If there are no DL,RR/FIFO tasks, there must only be CFS tasks left;
619 * if there's more than one we need the tick for involuntary
620 * preemption.
621 */
622 if (rq->nr_running > 1)
623 return false;
624
625 return true;
626}
627#endif /* CONFIG_NO_HZ_FULL */
628
629void sched_avg_update(struct rq *rq)
630{
631 s64 period = sched_avg_period();
632
633 while ((s64)(rq_clock(rq) - rq->age_stamp) > period) {
634 /*
635 * Inline assembly required to prevent the compiler
636 * optimising this loop into a divmod call.
637 * See __iter_div_u64_rem() for another example of this.
638 */
639 asm("" : "+rm" (rq->age_stamp));
640 rq->age_stamp += period;
641 rq->rt_avg /= 2;
642 }
643}
644
645#endif /* CONFIG_SMP */
646
647#if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \
648 (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH)))
649/*
650 * Iterate task_group tree rooted at *from, calling @down when first entering a
651 * node and @up when leaving it for the final time.
652 *
653 * Caller must hold rcu_lock or sufficient equivalent.
654 */
655int walk_tg_tree_from(struct task_group *from,
656 tg_visitor down, tg_visitor up, void *data)
657{
658 struct task_group *parent, *child;
659 int ret;
660
661 parent = from;
662
663down:
664 ret = (*down)(parent, data);
665 if (ret)
666 goto out;
667 list_for_each_entry_rcu(child, &parent->children, siblings) {
668 parent = child;
669 goto down;
670
671up:
672 continue;
673 }
674 ret = (*up)(parent, data);
675 if (ret || parent == from)
676 goto out;
677
678 child = parent;
679 parent = parent->parent;
680 if (parent)
681 goto up;
682out:
683 return ret;
684}
685
686int tg_nop(struct task_group *tg, void *data)
687{
688 return 0;
689}
690#endif
691
692static void set_load_weight(struct task_struct *p)
693{
694 int prio = p->static_prio - MAX_RT_PRIO;
695 struct load_weight *load = &p->se.load;
696
697 /*
698 * SCHED_IDLE tasks get minimal weight:
699 */
700 if (idle_policy(p->policy)) {
701 load->weight = scale_load(WEIGHT_IDLEPRIO);
702 load->inv_weight = WMULT_IDLEPRIO;
703 return;
704 }
705
706 load->weight = scale_load(sched_prio_to_weight[prio]);
707 load->inv_weight = sched_prio_to_wmult[prio];
708}
709
710static inline void enqueue_task(struct rq *rq, struct task_struct *p, int flags)
711{
712 update_rq_clock(rq);
713 if (!(flags & ENQUEUE_RESTORE))
714 sched_info_queued(rq, p);
715 p->sched_class->enqueue_task(rq, p, flags);
716}
717
718static inline void dequeue_task(struct rq *rq, struct task_struct *p, int flags)
719{
720 update_rq_clock(rq);
721 if (!(flags & DEQUEUE_SAVE))
722 sched_info_dequeued(rq, p);
723 p->sched_class->dequeue_task(rq, p, flags);
724}
725
726void activate_task(struct rq *rq, struct task_struct *p, int flags)
727{
728 if (task_contributes_to_load(p))
729 rq->nr_uninterruptible--;
730
731 enqueue_task(rq, p, flags);
732}
733
734void deactivate_task(struct rq *rq, struct task_struct *p, int flags)
735{
736 if (task_contributes_to_load(p))
737 rq->nr_uninterruptible++;
738
739 dequeue_task(rq, p, flags);
740}
741
742static void update_rq_clock_task(struct rq *rq, s64 delta)
743{
744/*
745 * In theory, the compile should just see 0 here, and optimize out the call
746 * to sched_rt_avg_update. But I don't trust it...
747 */
748#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
749 s64 steal = 0, irq_delta = 0;
750#endif
751#ifdef CONFIG_IRQ_TIME_ACCOUNTING
752 irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time;
753
754 /*
755 * Since irq_time is only updated on {soft,}irq_exit, we might run into
756 * this case when a previous update_rq_clock() happened inside a
757 * {soft,}irq region.
758 *
759 * When this happens, we stop ->clock_task and only update the
760 * prev_irq_time stamp to account for the part that fit, so that a next
761 * update will consume the rest. This ensures ->clock_task is
762 * monotonic.
763 *
764 * It does however cause some slight miss-attribution of {soft,}irq
765 * time, a more accurate solution would be to update the irq_time using
766 * the current rq->clock timestamp, except that would require using
767 * atomic ops.
768 */
769 if (irq_delta > delta)
770 irq_delta = delta;
771
772 rq->prev_irq_time += irq_delta;
773 delta -= irq_delta;
774#endif
775#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
776 if (static_key_false((¶virt_steal_rq_enabled))) {
777 steal = paravirt_steal_clock(cpu_of(rq));
778 steal -= rq->prev_steal_time_rq;
779
780 if (unlikely(steal > delta))
781 steal = delta;
782
783 rq->prev_steal_time_rq += steal;
784 delta -= steal;
785 }
786#endif
787
788 rq->clock_task += delta;
789
790#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
791 if ((irq_delta + steal) && sched_feat(NONTASK_CAPACITY))
792 sched_rt_avg_update(rq, irq_delta + steal);
793#endif
794}
795
796void sched_set_stop_task(int cpu, struct task_struct *stop)
797{
798 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
799 struct task_struct *old_stop = cpu_rq(cpu)->stop;
800
801 if (stop) {
802 /*
803 * Make it appear like a SCHED_FIFO task, its something
804 * userspace knows about and won't get confused about.
805 *
806 * Also, it will make PI more or less work without too
807 * much confusion -- but then, stop work should not
808 * rely on PI working anyway.
809 */
810 sched_setscheduler_nocheck(stop, SCHED_FIFO, ¶m);
811
812 stop->sched_class = &stop_sched_class;
813 }
814
815 cpu_rq(cpu)->stop = stop;
816
817 if (old_stop) {
818 /*
819 * Reset it back to a normal scheduling class so that
820 * it can die in pieces.
821 */
822 old_stop->sched_class = &rt_sched_class;
823 }
824}
825
826/*
827 * __normal_prio - return the priority that is based on the static prio
828 */
829static inline int __normal_prio(struct task_struct *p)
830{
831 return p->static_prio;
832}
833
834/*
835 * Calculate the expected normal priority: i.e. priority
836 * without taking RT-inheritance into account. Might be
837 * boosted by interactivity modifiers. Changes upon fork,
838 * setprio syscalls, and whenever the interactivity
839 * estimator recalculates.
840 */
841static inline int normal_prio(struct task_struct *p)
842{
843 int prio;
844
845 if (task_has_dl_policy(p))
846 prio = MAX_DL_PRIO-1;
847 else if (task_has_rt_policy(p))
848 prio = MAX_RT_PRIO-1 - p->rt_priority;
849 else
850 prio = __normal_prio(p);
851 return prio;
852}
853
854/*
855 * Calculate the current priority, i.e. the priority
856 * taken into account by the scheduler. This value might
857 * be boosted by RT tasks, or might be boosted by
858 * interactivity modifiers. Will be RT if the task got
859 * RT-boosted. If not then it returns p->normal_prio.
860 */
861static int effective_prio(struct task_struct *p)
862{
863 p->normal_prio = normal_prio(p);
864 /*
865 * If we are RT tasks or we were boosted to RT priority,
866 * keep the priority unchanged. Otherwise, update priority
867 * to the normal priority:
868 */
869 if (!rt_prio(p->prio))
870 return p->normal_prio;
871 return p->prio;
872}
873
874/**
875 * task_curr - is this task currently executing on a CPU?
876 * @p: the task in question.
877 *
878 * Return: 1 if the task is currently executing. 0 otherwise.
879 */
880inline int task_curr(const struct task_struct *p)
881{
882 return cpu_curr(task_cpu(p)) == p;
883}
884
885/*
886 * switched_from, switched_to and prio_changed must _NOT_ drop rq->lock,
887 * use the balance_callback list if you want balancing.
888 *
889 * this means any call to check_class_changed() must be followed by a call to
890 * balance_callback().
891 */
892static inline void check_class_changed(struct rq *rq, struct task_struct *p,
893 const struct sched_class *prev_class,
894 int oldprio)
895{
896 if (prev_class != p->sched_class) {
897 if (prev_class->switched_from)
898 prev_class->switched_from(rq, p);
899
900 p->sched_class->switched_to(rq, p);
901 } else if (oldprio != p->prio || dl_task(p))
902 p->sched_class->prio_changed(rq, p, oldprio);
903}
904
905void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags)
906{
907 const struct sched_class *class;
908
909 if (p->sched_class == rq->curr->sched_class) {
910 rq->curr->sched_class->check_preempt_curr(rq, p, flags);
911 } else {
912 for_each_class(class) {
913 if (class == rq->curr->sched_class)
914 break;
915 if (class == p->sched_class) {
916 resched_curr(rq);
917 break;
918 }
919 }
920 }
921
922 /*
923 * A queue event has occurred, and we're going to schedule. In
924 * this case, we can save a useless back to back clock update.
925 */
926 if (task_on_rq_queued(rq->curr) && test_tsk_need_resched(rq->curr))
927 rq_clock_skip_update(rq, true);
928}
929
930#ifdef CONFIG_SMP
931/*
932 * This is how migration works:
933 *
934 * 1) we invoke migration_cpu_stop() on the target CPU using
935 * stop_one_cpu().
936 * 2) stopper starts to run (implicitly forcing the migrated thread
937 * off the CPU)
938 * 3) it checks whether the migrated task is still in the wrong runqueue.
939 * 4) if it's in the wrong runqueue then the migration thread removes
940 * it and puts it into the right queue.
941 * 5) stopper completes and stop_one_cpu() returns and the migration
942 * is done.
943 */
944
945/*
946 * move_queued_task - move a queued task to new rq.
947 *
948 * Returns (locked) new rq. Old rq's lock is released.
949 */
950static struct rq *move_queued_task(struct rq *rq, struct task_struct *p, int new_cpu)
951{
952 lockdep_assert_held(&rq->lock);
953
954 p->on_rq = TASK_ON_RQ_MIGRATING;
955 dequeue_task(rq, p, 0);
956 set_task_cpu(p, new_cpu);
957 raw_spin_unlock(&rq->lock);
958
959 rq = cpu_rq(new_cpu);
960
961 raw_spin_lock(&rq->lock);
962 BUG_ON(task_cpu(p) != new_cpu);
963 enqueue_task(rq, p, 0);
964 p->on_rq = TASK_ON_RQ_QUEUED;
965 check_preempt_curr(rq, p, 0);
966
967 return rq;
968}
969
970struct migration_arg {
971 struct task_struct *task;
972 int dest_cpu;
973};
974
975/*
976 * Move (not current) task off this cpu, onto dest cpu. We're doing
977 * this because either it can't run here any more (set_cpus_allowed()
978 * away from this CPU, or CPU going down), or because we're
979 * attempting to rebalance this task on exec (sched_exec).
980 *
981 * So we race with normal scheduler movements, but that's OK, as long
982 * as the task is no longer on this CPU.
983 */
984static struct rq *__migrate_task(struct rq *rq, struct task_struct *p, int dest_cpu)
985{
986 if (unlikely(!cpu_active(dest_cpu)))
987 return rq;
988
989 /* Affinity changed (again). */
990 if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p)))
991 return rq;
992
993 rq = move_queued_task(rq, p, dest_cpu);
994
995 return rq;
996}
997
998/*
999 * migration_cpu_stop - this will be executed by a highprio stopper thread
1000 * and performs thread migration by bumping thread off CPU then
1001 * 'pushing' onto another runqueue.
1002 */
1003static int migration_cpu_stop(void *data)
1004{
1005 struct migration_arg *arg = data;
1006 struct task_struct *p = arg->task;
1007 struct rq *rq = this_rq();
1008
1009 /*
1010 * The original target cpu might have gone down and we might
1011 * be on another cpu but it doesn't matter.
1012 */
1013 local_irq_disable();
1014 /*
1015 * We need to explicitly wake pending tasks before running
1016 * __migrate_task() such that we will not miss enforcing cpus_allowed
1017 * during wakeups, see set_cpus_allowed_ptr()'s TASK_WAKING test.
1018 */
1019 sched_ttwu_pending();
1020
1021 raw_spin_lock(&p->pi_lock);
1022 raw_spin_lock(&rq->lock);
1023 /*
1024 * If task_rq(p) != rq, it cannot be migrated here, because we're
1025 * holding rq->lock, if p->on_rq == 0 it cannot get enqueued because
1026 * we're holding p->pi_lock.
1027 */
1028 if (task_rq(p) == rq && task_on_rq_queued(p))
1029 rq = __migrate_task(rq, p, arg->dest_cpu);
1030 raw_spin_unlock(&rq->lock);
1031 raw_spin_unlock(&p->pi_lock);
1032
1033 local_irq_enable();
1034 return 0;
1035}
1036
1037/*
1038 * sched_class::set_cpus_allowed must do the below, but is not required to
1039 * actually call this function.
1040 */
1041void set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_mask)
1042{
1043 cpumask_copy(&p->cpus_allowed, new_mask);
1044 p->nr_cpus_allowed = cpumask_weight(new_mask);
1045}
1046
1047void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
1048{
1049 struct rq *rq = task_rq(p);
1050 bool queued, running;
1051
1052 lockdep_assert_held(&p->pi_lock);
1053
1054 queued = task_on_rq_queued(p);
1055 running = task_current(rq, p);
1056
1057 if (queued) {
1058 /*
1059 * Because __kthread_bind() calls this on blocked tasks without
1060 * holding rq->lock.
1061 */
1062 lockdep_assert_held(&rq->lock);
1063 dequeue_task(rq, p, DEQUEUE_SAVE);
1064 }
1065 if (running)
1066 put_prev_task(rq, p);
1067
1068 p->sched_class->set_cpus_allowed(p, new_mask);
1069
1070 if (running)
1071 p->sched_class->set_curr_task(rq);
1072 if (queued)
1073 enqueue_task(rq, p, ENQUEUE_RESTORE);
1074}
1075
1076/*
1077 * Change a given task's CPU affinity. Migrate the thread to a
1078 * proper CPU and schedule it away if the CPU it's executing on
1079 * is removed from the allowed bitmask.
1080 *
1081 * NOTE: the caller must have a valid reference to the task, the
1082 * task must not exit() & deallocate itself prematurely. The
1083 * call is not atomic; no spinlocks may be held.
1084 */
1085static int __set_cpus_allowed_ptr(struct task_struct *p,
1086 const struct cpumask *new_mask, bool check)
1087{
1088 unsigned long flags;
1089 struct rq *rq;
1090 unsigned int dest_cpu;
1091 int ret = 0;
1092
1093 rq = task_rq_lock(p, &flags);
1094
1095 /*
1096 * Must re-check here, to close a race against __kthread_bind(),
1097 * sched_setaffinity() is not guaranteed to observe the flag.
1098 */
1099 if (check && (p->flags & PF_NO_SETAFFINITY)) {
1100 ret = -EINVAL;
1101 goto out;
1102 }
1103
1104 if (cpumask_equal(&p->cpus_allowed, new_mask))
1105 goto out;
1106
1107 if (!cpumask_intersects(new_mask, cpu_active_mask)) {
1108 ret = -EINVAL;
1109 goto out;
1110 }
1111
1112 do_set_cpus_allowed(p, new_mask);
1113
1114 /* Can the task run on the task's current CPU? If so, we're done */
1115 if (cpumask_test_cpu(task_cpu(p), new_mask))
1116 goto out;
1117
1118 dest_cpu = cpumask_any_and(cpu_active_mask, new_mask);
1119 if (task_running(rq, p) || p->state == TASK_WAKING) {
1120 struct migration_arg arg = { p, dest_cpu };
1121 /* Need help from migration thread: drop lock and wait. */
1122 task_rq_unlock(rq, p, &flags);
1123 stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg);
1124 tlb_migrate_finish(p->mm);
1125 return 0;
1126 } else if (task_on_rq_queued(p)) {
1127 /*
1128 * OK, since we're going to drop the lock immediately
1129 * afterwards anyway.
1130 */
1131 lockdep_unpin_lock(&rq->lock);
1132 rq = move_queued_task(rq, p, dest_cpu);
1133 lockdep_pin_lock(&rq->lock);
1134 }
1135out:
1136 task_rq_unlock(rq, p, &flags);
1137
1138 return ret;
1139}
1140
1141int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
1142{
1143 return __set_cpus_allowed_ptr(p, new_mask, false);
1144}
1145EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
1146
1147void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
1148{
1149#ifdef CONFIG_SCHED_DEBUG
1150 /*
1151 * We should never call set_task_cpu() on a blocked task,
1152 * ttwu() will sort out the placement.
1153 */
1154 WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING &&
1155 !p->on_rq);
1156
1157 /*
1158 * Migrating fair class task must have p->on_rq = TASK_ON_RQ_MIGRATING,
1159 * because schedstat_wait_{start,end} rebase migrating task's wait_start
1160 * time relying on p->on_rq.
1161 */
1162 WARN_ON_ONCE(p->state == TASK_RUNNING &&
1163 p->sched_class == &fair_sched_class &&
1164 (p->on_rq && !task_on_rq_migrating(p)));
1165
1166#ifdef CONFIG_LOCKDEP
1167 /*
1168 * The caller should hold either p->pi_lock or rq->lock, when changing
1169 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
1170 *
1171 * sched_move_task() holds both and thus holding either pins the cgroup,
1172 * see task_group().
1173 *
1174 * Furthermore, all task_rq users should acquire both locks, see
1175 * task_rq_lock().
1176 */
1177 WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) ||
1178 lockdep_is_held(&task_rq(p)->lock)));
1179#endif
1180#endif
1181
1182 trace_sched_migrate_task(p, new_cpu);
1183
1184 if (task_cpu(p) != new_cpu) {
1185 if (p->sched_class->migrate_task_rq)
1186 p->sched_class->migrate_task_rq(p);
1187 p->se.nr_migrations++;
1188 perf_event_task_migrate(p);
1189 }
1190
1191 __set_task_cpu(p, new_cpu);
1192}
1193
1194static void __migrate_swap_task(struct task_struct *p, int cpu)
1195{
1196 if (task_on_rq_queued(p)) {
1197 struct rq *src_rq, *dst_rq;
1198
1199 src_rq = task_rq(p);
1200 dst_rq = cpu_rq(cpu);
1201
1202 p->on_rq = TASK_ON_RQ_MIGRATING;
1203 deactivate_task(src_rq, p, 0);
1204 set_task_cpu(p, cpu);
1205 activate_task(dst_rq, p, 0);
1206 p->on_rq = TASK_ON_RQ_QUEUED;
1207 check_preempt_curr(dst_rq, p, 0);
1208 } else {
1209 /*
1210 * Task isn't running anymore; make it appear like we migrated
1211 * it before it went to sleep. This means on wakeup we make the
1212 * previous cpu our targer instead of where it really is.
1213 */
1214 p->wake_cpu = cpu;
1215 }
1216}
1217
1218struct migration_swap_arg {
1219 struct task_struct *src_task, *dst_task;
1220 int src_cpu, dst_cpu;
1221};
1222
1223static int migrate_swap_stop(void *data)
1224{
1225 struct migration_swap_arg *arg = data;
1226 struct rq *src_rq, *dst_rq;
1227 int ret = -EAGAIN;
1228
1229 if (!cpu_active(arg->src_cpu) || !cpu_active(arg->dst_cpu))
1230 return -EAGAIN;
1231
1232 src_rq = cpu_rq(arg->src_cpu);
1233 dst_rq = cpu_rq(arg->dst_cpu);
1234
1235 double_raw_lock(&arg->src_task->pi_lock,
1236 &arg->dst_task->pi_lock);
1237 double_rq_lock(src_rq, dst_rq);
1238
1239 if (task_cpu(arg->dst_task) != arg->dst_cpu)
1240 goto unlock;
1241
1242 if (task_cpu(arg->src_task) != arg->src_cpu)
1243 goto unlock;
1244
1245 if (!cpumask_test_cpu(arg->dst_cpu, tsk_cpus_allowed(arg->src_task)))
1246 goto unlock;
1247
1248 if (!cpumask_test_cpu(arg->src_cpu, tsk_cpus_allowed(arg->dst_task)))
1249 goto unlock;
1250
1251 __migrate_swap_task(arg->src_task, arg->dst_cpu);
1252 __migrate_swap_task(arg->dst_task, arg->src_cpu);
1253
1254 ret = 0;
1255
1256unlock:
1257 double_rq_unlock(src_rq, dst_rq);
1258 raw_spin_unlock(&arg->dst_task->pi_lock);
1259 raw_spin_unlock(&arg->src_task->pi_lock);
1260
1261 return ret;
1262}
1263
1264/*
1265 * Cross migrate two tasks
1266 */
1267int migrate_swap(struct task_struct *cur, struct task_struct *p)
1268{
1269 struct migration_swap_arg arg;
1270 int ret = -EINVAL;
1271
1272 arg = (struct migration_swap_arg){
1273 .src_task = cur,
1274 .src_cpu = task_cpu(cur),
1275 .dst_task = p,
1276 .dst_cpu = task_cpu(p),
1277 };
1278
1279 if (arg.src_cpu == arg.dst_cpu)
1280 goto out;
1281
1282 /*
1283 * These three tests are all lockless; this is OK since all of them
1284 * will be re-checked with proper locks held further down the line.
1285 */
1286 if (!cpu_active(arg.src_cpu) || !cpu_active(arg.dst_cpu))
1287 goto out;
1288
1289 if (!cpumask_test_cpu(arg.dst_cpu, tsk_cpus_allowed(arg.src_task)))
1290 goto out;
1291
1292 if (!cpumask_test_cpu(arg.src_cpu, tsk_cpus_allowed(arg.dst_task)))
1293 goto out;
1294
1295 trace_sched_swap_numa(cur, arg.src_cpu, p, arg.dst_cpu);
1296 ret = stop_two_cpus(arg.dst_cpu, arg.src_cpu, migrate_swap_stop, &arg);
1297
1298out:
1299 return ret;
1300}
1301
1302/*
1303 * wait_task_inactive - wait for a thread to unschedule.
1304 *
1305 * If @match_state is nonzero, it's the @p->state value just checked and
1306 * not expected to change. If it changes, i.e. @p might have woken up,
1307 * then return zero. When we succeed in waiting for @p to be off its CPU,
1308 * we return a positive number (its total switch count). If a second call
1309 * a short while later returns the same number, the caller can be sure that
1310 * @p has remained unscheduled the whole time.
1311 *
1312 * The caller must ensure that the task *will* unschedule sometime soon,
1313 * else this function might spin for a *long* time. This function can't
1314 * be called with interrupts off, or it may introduce deadlock with
1315 * smp_call_function() if an IPI is sent by the same process we are
1316 * waiting to become inactive.
1317 */
1318unsigned long wait_task_inactive(struct task_struct *p, long match_state)
1319{
1320 unsigned long flags;
1321 int running, queued;
1322 unsigned long ncsw;
1323 struct rq *rq;
1324
1325 for (;;) {
1326 /*
1327 * We do the initial early heuristics without holding
1328 * any task-queue locks at all. We'll only try to get
1329 * the runqueue lock when things look like they will
1330 * work out!
1331 */
1332 rq = task_rq(p);
1333
1334 /*
1335 * If the task is actively running on another CPU
1336 * still, just relax and busy-wait without holding
1337 * any locks.
1338 *
1339 * NOTE! Since we don't hold any locks, it's not
1340 * even sure that "rq" stays as the right runqueue!
1341 * But we don't care, since "task_running()" will
1342 * return false if the runqueue has changed and p
1343 * is actually now running somewhere else!
1344 */
1345 while (task_running(rq, p)) {
1346 if (match_state && unlikely(p->state != match_state))
1347 return 0;
1348 cpu_relax();
1349 }
1350
1351 /*
1352 * Ok, time to look more closely! We need the rq
1353 * lock now, to be *sure*. If we're wrong, we'll
1354 * just go back and repeat.
1355 */
1356 rq = task_rq_lock(p, &flags);
1357 trace_sched_wait_task(p);
1358 running = task_running(rq, p);
1359 queued = task_on_rq_queued(p);
1360 ncsw = 0;
1361 if (!match_state || p->state == match_state)
1362 ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
1363 task_rq_unlock(rq, p, &flags);
1364
1365 /*
1366 * If it changed from the expected state, bail out now.
1367 */
1368 if (unlikely(!ncsw))
1369 break;
1370
1371 /*
1372 * Was it really running after all now that we
1373 * checked with the proper locks actually held?
1374 *
1375 * Oops. Go back and try again..
1376 */
1377 if (unlikely(running)) {
1378 cpu_relax();
1379 continue;
1380 }
1381
1382 /*
1383 * It's not enough that it's not actively running,
1384 * it must be off the runqueue _entirely_, and not
1385 * preempted!
1386 *
1387 * So if it was still runnable (but just not actively
1388 * running right now), it's preempted, and we should
1389 * yield - it could be a while.
1390 */
1391 if (unlikely(queued)) {
1392 ktime_t to = ktime_set(0, NSEC_PER_SEC/HZ);
1393
1394 set_current_state(TASK_UNINTERRUPTIBLE);
1395 schedule_hrtimeout(&to, HRTIMER_MODE_REL);
1396 continue;
1397 }
1398
1399 /*
1400 * Ahh, all good. It wasn't running, and it wasn't
1401 * runnable, which means that it will never become
1402 * running in the future either. We're all done!
1403 */
1404 break;
1405 }
1406
1407 return ncsw;
1408}
1409
1410/***
1411 * kick_process - kick a running thread to enter/exit the kernel
1412 * @p: the to-be-kicked thread
1413 *
1414 * Cause a process which is running on another CPU to enter
1415 * kernel-mode, without any delay. (to get signals handled.)
1416 *
1417 * NOTE: this function doesn't have to take the runqueue lock,
1418 * because all it wants to ensure is that the remote task enters
1419 * the kernel. If the IPI races and the task has been migrated
1420 * to another CPU then no harm is done and the purpose has been
1421 * achieved as well.
1422 */
1423void kick_process(struct task_struct *p)
1424{
1425 int cpu;
1426
1427 preempt_disable();
1428 cpu = task_cpu(p);
1429 if ((cpu != smp_processor_id()) && task_curr(p))
1430 smp_send_reschedule(cpu);
1431 preempt_enable();
1432}
1433EXPORT_SYMBOL_GPL(kick_process);
1434
1435/*
1436 * ->cpus_allowed is protected by both rq->lock and p->pi_lock
1437 */
1438static int select_fallback_rq(int cpu, struct task_struct *p)
1439{
1440 int nid = cpu_to_node(cpu);
1441 const struct cpumask *nodemask = NULL;
1442 enum { cpuset, possible, fail } state = cpuset;
1443 int dest_cpu;
1444
1445 /*
1446 * If the node that the cpu is on has been offlined, cpu_to_node()
1447 * will return -1. There is no cpu on the node, and we should
1448 * select the cpu on the other node.
1449 */
1450 if (nid != -1) {
1451 nodemask = cpumask_of_node(nid);
1452
1453 /* Look for allowed, online CPU in same node. */
1454 for_each_cpu(dest_cpu, nodemask) {
1455 if (!cpu_online(dest_cpu))
1456 continue;
1457 if (!cpu_active(dest_cpu))
1458 continue;
1459 if (cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p)))
1460 return dest_cpu;
1461 }
1462 }
1463
1464 for (;;) {
1465 /* Any allowed, online CPU? */
1466 for_each_cpu(dest_cpu, tsk_cpus_allowed(p)) {
1467 if (!cpu_online(dest_cpu))
1468 continue;
1469 if (!cpu_active(dest_cpu))
1470 continue;
1471 goto out;
1472 }
1473
1474 /* No more Mr. Nice Guy. */
1475 switch (state) {
1476 case cpuset:
1477 if (IS_ENABLED(CONFIG_CPUSETS)) {
1478 cpuset_cpus_allowed_fallback(p);
1479 state = possible;
1480 break;
1481 }
1482 /* fall-through */
1483 case possible:
1484 do_set_cpus_allowed(p, cpu_possible_mask);
1485 state = fail;
1486 break;
1487
1488 case fail:
1489 BUG();
1490 break;
1491 }
1492 }
1493
1494out:
1495 if (state != cpuset) {
1496 /*
1497 * Don't tell them about moving exiting tasks or
1498 * kernel threads (both mm NULL), since they never
1499 * leave kernel.
1500 */
1501 if (p->mm && printk_ratelimit()) {
1502 printk_deferred("process %d (%s) no longer affine to cpu%d\n",
1503 task_pid_nr(p), p->comm, cpu);
1504 }
1505 }
1506
1507 return dest_cpu;
1508}
1509
1510/*
1511 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable.
1512 */
1513static inline
1514int select_task_rq(struct task_struct *p, int cpu, int sd_flags, int wake_flags)
1515{
1516 lockdep_assert_held(&p->pi_lock);
1517
1518 if (p->nr_cpus_allowed > 1)
1519 cpu = p->sched_class->select_task_rq(p, cpu, sd_flags, wake_flags);
1520
1521 /*
1522 * In order not to call set_task_cpu() on a blocking task we need
1523 * to rely on ttwu() to place the task on a valid ->cpus_allowed
1524 * cpu.
1525 *
1526 * Since this is common to all placement strategies, this lives here.
1527 *
1528 * [ this allows ->select_task() to simply return task_cpu(p) and
1529 * not worry about this generic constraint ]
1530 */
1531 if (unlikely(!cpumask_test_cpu(cpu, tsk_cpus_allowed(p)) ||
1532 !cpu_online(cpu)))
1533 cpu = select_fallback_rq(task_cpu(p), p);
1534
1535 return cpu;
1536}
1537
1538static void update_avg(u64 *avg, u64 sample)
1539{
1540 s64 diff = sample - *avg;
1541 *avg += diff >> 3;
1542}
1543
1544#else
1545
1546static inline int __set_cpus_allowed_ptr(struct task_struct *p,
1547 const struct cpumask *new_mask, bool check)
1548{
1549 return set_cpus_allowed_ptr(p, new_mask);
1550}
1551
1552#endif /* CONFIG_SMP */
1553
1554static void
1555ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
1556{
1557#ifdef CONFIG_SCHEDSTATS
1558 struct rq *rq = this_rq();
1559
1560#ifdef CONFIG_SMP
1561 int this_cpu = smp_processor_id();
1562
1563 if (cpu == this_cpu) {
1564 schedstat_inc(rq, ttwu_local);
1565 schedstat_inc(p, se.statistics.nr_wakeups_local);
1566 } else {
1567 struct sched_domain *sd;
1568
1569 schedstat_inc(p, se.statistics.nr_wakeups_remote);
1570 rcu_read_lock();
1571 for_each_domain(this_cpu, sd) {
1572 if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
1573 schedstat_inc(sd, ttwu_wake_remote);
1574 break;
1575 }
1576 }
1577 rcu_read_unlock();
1578 }
1579
1580 if (wake_flags & WF_MIGRATED)
1581 schedstat_inc(p, se.statistics.nr_wakeups_migrate);
1582
1583#endif /* CONFIG_SMP */
1584
1585 schedstat_inc(rq, ttwu_count);
1586 schedstat_inc(p, se.statistics.nr_wakeups);
1587
1588 if (wake_flags & WF_SYNC)
1589 schedstat_inc(p, se.statistics.nr_wakeups_sync);
1590
1591#endif /* CONFIG_SCHEDSTATS */
1592}
1593
1594static inline void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags)
1595{
1596 activate_task(rq, p, en_flags);
1597 p->on_rq = TASK_ON_RQ_QUEUED;
1598
1599 /* if a worker is waking up, notify workqueue */
1600 if (p->flags & PF_WQ_WORKER)
1601 wq_worker_waking_up(p, cpu_of(rq));
1602}
1603
1604/*
1605 * Mark the task runnable and perform wakeup-preemption.
1606 */
1607static void
1608ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags)
1609{
1610 check_preempt_curr(rq, p, wake_flags);
1611 p->state = TASK_RUNNING;
1612 trace_sched_wakeup(p);
1613
1614#ifdef CONFIG_SMP
1615 if (p->sched_class->task_woken) {
1616 /*
1617 * Our task @p is fully woken up and running; so its safe to
1618 * drop the rq->lock, hereafter rq is only used for statistics.
1619 */
1620 lockdep_unpin_lock(&rq->lock);
1621 p->sched_class->task_woken(rq, p);
1622 lockdep_pin_lock(&rq->lock);
1623 }
1624
1625 if (rq->idle_stamp) {
1626 u64 delta = rq_clock(rq) - rq->idle_stamp;
1627 u64 max = 2*rq->max_idle_balance_cost;
1628
1629 update_avg(&rq->avg_idle, delta);
1630
1631 if (rq->avg_idle > max)
1632 rq->avg_idle = max;
1633
1634 rq->idle_stamp = 0;
1635 }
1636#endif
1637}
1638
1639static void
1640ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags)
1641{
1642 lockdep_assert_held(&rq->lock);
1643
1644#ifdef CONFIG_SMP
1645 if (p->sched_contributes_to_load)
1646 rq->nr_uninterruptible--;
1647#endif
1648
1649 ttwu_activate(rq, p, ENQUEUE_WAKEUP | ENQUEUE_WAKING);
1650 ttwu_do_wakeup(rq, p, wake_flags);
1651}
1652
1653/*
1654 * Called in case the task @p isn't fully descheduled from its runqueue,
1655 * in this case we must do a remote wakeup. Its a 'light' wakeup though,
1656 * since all we need to do is flip p->state to TASK_RUNNING, since
1657 * the task is still ->on_rq.
1658 */
1659static int ttwu_remote(struct task_struct *p, int wake_flags)
1660{
1661 struct rq *rq;
1662 int ret = 0;
1663
1664 rq = __task_rq_lock(p);
1665 if (task_on_rq_queued(p)) {
1666 /* check_preempt_curr() may use rq clock */
1667 update_rq_clock(rq);
1668 ttwu_do_wakeup(rq, p, wake_flags);
1669 ret = 1;
1670 }
1671 __task_rq_unlock(rq);
1672
1673 return ret;
1674}
1675
1676#ifdef CONFIG_SMP
1677void sched_ttwu_pending(void)
1678{
1679 struct rq *rq = this_rq();
1680 struct llist_node *llist = llist_del_all(&rq->wake_list);
1681 struct task_struct *p;
1682 unsigned long flags;
1683
1684 if (!llist)
1685 return;
1686
1687 raw_spin_lock_irqsave(&rq->lock, flags);
1688 lockdep_pin_lock(&rq->lock);
1689
1690 while (llist) {
1691 p = llist_entry(llist, struct task_struct, wake_entry);
1692 llist = llist_next(llist);
1693 ttwu_do_activate(rq, p, 0);
1694 }
1695
1696 lockdep_unpin_lock(&rq->lock);
1697 raw_spin_unlock_irqrestore(&rq->lock, flags);
1698}
1699
1700void scheduler_ipi(void)
1701{
1702 /*
1703 * Fold TIF_NEED_RESCHED into the preempt_count; anybody setting
1704 * TIF_NEED_RESCHED remotely (for the first time) will also send
1705 * this IPI.
1706 */
1707 preempt_fold_need_resched();
1708
1709 if (llist_empty(&this_rq()->wake_list) && !got_nohz_idle_kick())
1710 return;
1711
1712 /*
1713 * Not all reschedule IPI handlers call irq_enter/irq_exit, since
1714 * traditionally all their work was done from the interrupt return
1715 * path. Now that we actually do some work, we need to make sure
1716 * we do call them.
1717 *
1718 * Some archs already do call them, luckily irq_enter/exit nest
1719 * properly.
1720 *
1721 * Arguably we should visit all archs and update all handlers,
1722 * however a fair share of IPIs are still resched only so this would
1723 * somewhat pessimize the simple resched case.
1724 */
1725 irq_enter();
1726 sched_ttwu_pending();
1727
1728 /*
1729 * Check if someone kicked us for doing the nohz idle load balance.
1730 */
1731 if (unlikely(got_nohz_idle_kick())) {
1732 this_rq()->idle_balance = 1;
1733 raise_softirq_irqoff(SCHED_SOFTIRQ);
1734 }
1735 irq_exit();
1736}
1737
1738static void ttwu_queue_remote(struct task_struct *p, int cpu)
1739{
1740 struct rq *rq = cpu_rq(cpu);
1741
1742 if (llist_add(&p->wake_entry, &cpu_rq(cpu)->wake_list)) {
1743 if (!set_nr_if_polling(rq->idle))
1744 smp_send_reschedule(cpu);
1745 else
1746 trace_sched_wake_idle_without_ipi(cpu);
1747 }
1748}
1749
1750void wake_up_if_idle(int cpu)
1751{
1752 struct rq *rq = cpu_rq(cpu);
1753 unsigned long flags;
1754
1755 rcu_read_lock();
1756
1757 if (!is_idle_task(rcu_dereference(rq->curr)))
1758 goto out;
1759
1760 if (set_nr_if_polling(rq->idle)) {
1761 trace_sched_wake_idle_without_ipi(cpu);
1762 } else {
1763 raw_spin_lock_irqsave(&rq->lock, flags);
1764 if (is_idle_task(rq->curr))
1765 smp_send_reschedule(cpu);
1766 /* Else cpu is not in idle, do nothing here */
1767 raw_spin_unlock_irqrestore(&rq->lock, flags);
1768 }
1769
1770out:
1771 rcu_read_unlock();
1772}
1773
1774bool cpus_share_cache(int this_cpu, int that_cpu)
1775{
1776 return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu);
1777}
1778#endif /* CONFIG_SMP */
1779
1780static void ttwu_queue(struct task_struct *p, int cpu)
1781{
1782 struct rq *rq = cpu_rq(cpu);
1783
1784#if defined(CONFIG_SMP)
1785 if (sched_feat(TTWU_QUEUE) && !cpus_share_cache(smp_processor_id(), cpu)) {
1786 sched_clock_cpu(cpu); /* sync clocks x-cpu */
1787 ttwu_queue_remote(p, cpu);
1788 return;
1789 }
1790#endif
1791
1792 raw_spin_lock(&rq->lock);
1793 lockdep_pin_lock(&rq->lock);
1794 ttwu_do_activate(rq, p, 0);
1795 lockdep_unpin_lock(&rq->lock);
1796 raw_spin_unlock(&rq->lock);
1797}
1798
1799/*
1800 * Notes on Program-Order guarantees on SMP systems.
1801 *
1802 * MIGRATION
1803 *
1804 * The basic program-order guarantee on SMP systems is that when a task [t]
1805 * migrates, all its activity on its old cpu [c0] happens-before any subsequent
1806 * execution on its new cpu [c1].
1807 *
1808 * For migration (of runnable tasks) this is provided by the following means:
1809 *
1810 * A) UNLOCK of the rq(c0)->lock scheduling out task t
1811 * B) migration for t is required to synchronize *both* rq(c0)->lock and
1812 * rq(c1)->lock (if not at the same time, then in that order).
1813 * C) LOCK of the rq(c1)->lock scheduling in task
1814 *
1815 * Transitivity guarantees that B happens after A and C after B.
1816 * Note: we only require RCpc transitivity.
1817 * Note: the cpu doing B need not be c0 or c1
1818 *
1819 * Example:
1820 *
1821 * CPU0 CPU1 CPU2
1822 *
1823 * LOCK rq(0)->lock
1824 * sched-out X
1825 * sched-in Y
1826 * UNLOCK rq(0)->lock
1827 *
1828 * LOCK rq(0)->lock // orders against CPU0
1829 * dequeue X
1830 * UNLOCK rq(0)->lock
1831 *
1832 * LOCK rq(1)->lock
1833 * enqueue X
1834 * UNLOCK rq(1)->lock
1835 *
1836 * LOCK rq(1)->lock // orders against CPU2
1837 * sched-out Z
1838 * sched-in X
1839 * UNLOCK rq(1)->lock
1840 *
1841 *
1842 * BLOCKING -- aka. SLEEP + WAKEUP
1843 *
1844 * For blocking we (obviously) need to provide the same guarantee as for
1845 * migration. However the means are completely different as there is no lock
1846 * chain to provide order. Instead we do:
1847 *
1848 * 1) smp_store_release(X->on_cpu, 0)
1849 * 2) smp_cond_acquire(!X->on_cpu)
1850 *
1851 * Example:
1852 *
1853 * CPU0 (schedule) CPU1 (try_to_wake_up) CPU2 (schedule)
1854 *
1855 * LOCK rq(0)->lock LOCK X->pi_lock
1856 * dequeue X
1857 * sched-out X
1858 * smp_store_release(X->on_cpu, 0);
1859 *
1860 * smp_cond_acquire(!X->on_cpu);
1861 * X->state = WAKING
1862 * set_task_cpu(X,2)
1863 *
1864 * LOCK rq(2)->lock
1865 * enqueue X
1866 * X->state = RUNNING
1867 * UNLOCK rq(2)->lock
1868 *
1869 * LOCK rq(2)->lock // orders against CPU1
1870 * sched-out Z
1871 * sched-in X
1872 * UNLOCK rq(2)->lock
1873 *
1874 * UNLOCK X->pi_lock
1875 * UNLOCK rq(0)->lock
1876 *
1877 *
1878 * However; for wakeups there is a second guarantee we must provide, namely we
1879 * must observe the state that lead to our wakeup. That is, not only must our
1880 * task observe its own prior state, it must also observe the stores prior to
1881 * its wakeup.
1882 *
1883 * This means that any means of doing remote wakeups must order the CPU doing
1884 * the wakeup against the CPU the task is going to end up running on. This,
1885 * however, is already required for the regular Program-Order guarantee above,
1886 * since the waking CPU is the one issueing the ACQUIRE (smp_cond_acquire).
1887 *
1888 */
1889
1890/**
1891 * try_to_wake_up - wake up a thread
1892 * @p: the thread to be awakened
1893 * @state: the mask of task states that can be woken
1894 * @wake_flags: wake modifier flags (WF_*)
1895 *
1896 * Put it on the run-queue if it's not already there. The "current"
1897 * thread is always on the run-queue (except when the actual
1898 * re-schedule is in progress), and as such you're allowed to do
1899 * the simpler "current->state = TASK_RUNNING" to mark yourself
1900 * runnable without the overhead of this.
1901 *
1902 * Return: %true if @p was woken up, %false if it was already running.
1903 * or @state didn't match @p's state.
1904 */
1905static int
1906try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
1907{
1908 unsigned long flags;
1909 int cpu, success = 0;
1910
1911 /*
1912 * If we are going to wake up a thread waiting for CONDITION we
1913 * need to ensure that CONDITION=1 done by the caller can not be
1914 * reordered with p->state check below. This pairs with mb() in
1915 * set_current_state() the waiting thread does.
1916 */
1917 smp_mb__before_spinlock();
1918 raw_spin_lock_irqsave(&p->pi_lock, flags);
1919 if (!(p->state & state))
1920 goto out;
1921
1922 trace_sched_waking(p);
1923
1924 success = 1; /* we're going to change ->state */
1925 cpu = task_cpu(p);
1926
1927 if (p->on_rq && ttwu_remote(p, wake_flags))
1928 goto stat;
1929
1930#ifdef CONFIG_SMP
1931 /*
1932 * Ensure we load p->on_cpu _after_ p->on_rq, otherwise it would be
1933 * possible to, falsely, observe p->on_cpu == 0.
1934 *
1935 * One must be running (->on_cpu == 1) in order to remove oneself
1936 * from the runqueue.
1937 *
1938 * [S] ->on_cpu = 1; [L] ->on_rq
1939 * UNLOCK rq->lock
1940 * RMB
1941 * LOCK rq->lock
1942 * [S] ->on_rq = 0; [L] ->on_cpu
1943 *
1944 * Pairs with the full barrier implied in the UNLOCK+LOCK on rq->lock
1945 * from the consecutive calls to schedule(); the first switching to our
1946 * task, the second putting it to sleep.
1947 */
1948 smp_rmb();
1949
1950 /*
1951 * If the owning (remote) cpu is still in the middle of schedule() with
1952 * this task as prev, wait until its done referencing the task.
1953 *
1954 * Pairs with the smp_store_release() in finish_lock_switch().
1955 *
1956 * This ensures that tasks getting woken will be fully ordered against
1957 * their previous state and preserve Program Order.
1958 */
1959 smp_cond_acquire(!p->on_cpu);
1960
1961 p->sched_contributes_to_load = !!task_contributes_to_load(p);
1962 p->state = TASK_WAKING;
1963
1964 if (p->sched_class->task_waking)
1965 p->sched_class->task_waking(p);
1966
1967 cpu = select_task_rq(p, p->wake_cpu, SD_BALANCE_WAKE, wake_flags);
1968 if (task_cpu(p) != cpu) {
1969 wake_flags |= WF_MIGRATED;
1970 set_task_cpu(p, cpu);
1971 }
1972#endif /* CONFIG_SMP */
1973
1974 ttwu_queue(p, cpu);
1975stat:
1976 if (schedstat_enabled())
1977 ttwu_stat(p, cpu, wake_flags);
1978out:
1979 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
1980
1981 return success;
1982}
1983
1984/**
1985 * try_to_wake_up_local - try to wake up a local task with rq lock held
1986 * @p: the thread to be awakened
1987 *
1988 * Put @p on the run-queue if it's not already there. The caller must
1989 * ensure that this_rq() is locked, @p is bound to this_rq() and not
1990 * the current task.
1991 */
1992static void try_to_wake_up_local(struct task_struct *p)
1993{
1994 struct rq *rq = task_rq(p);
1995
1996 if (WARN_ON_ONCE(rq != this_rq()) ||
1997 WARN_ON_ONCE(p == current))
1998 return;
1999
2000 lockdep_assert_held(&rq->lock);
2001
2002 if (!raw_spin_trylock(&p->pi_lock)) {
2003 /*
2004 * This is OK, because current is on_cpu, which avoids it being
2005 * picked for load-balance and preemption/IRQs are still
2006 * disabled avoiding further scheduler activity on it and we've
2007 * not yet picked a replacement task.
2008 */
2009 lockdep_unpin_lock(&rq->lock);
2010 raw_spin_unlock(&rq->lock);
2011 raw_spin_lock(&p->pi_lock);
2012 raw_spin_lock(&rq->lock);
2013 lockdep_pin_lock(&rq->lock);
2014 }
2015
2016 if (!(p->state & TASK_NORMAL))
2017 goto out;
2018
2019 trace_sched_waking(p);
2020
2021 if (!task_on_rq_queued(p))
2022 ttwu_activate(rq, p, ENQUEUE_WAKEUP);
2023
2024 ttwu_do_wakeup(rq, p, 0);
2025 if (schedstat_enabled())
2026 ttwu_stat(p, smp_processor_id(), 0);
2027out:
2028 raw_spin_unlock(&p->pi_lock);
2029}
2030
2031/**
2032 * wake_up_process - Wake up a specific process
2033 * @p: The process to be woken up.
2034 *
2035 * Attempt to wake up the nominated process and move it to the set of runnable
2036 * processes.
2037 *
2038 * Return: 1 if the process was woken up, 0 if it was already running.
2039 *
2040 * It may be assumed that this function implies a write memory barrier before
2041 * changing the task state if and only if any tasks are woken up.
2042 */
2043int wake_up_process(struct task_struct *p)
2044{
2045 return try_to_wake_up(p, TASK_NORMAL, 0);
2046}
2047EXPORT_SYMBOL(wake_up_process);
2048
2049int wake_up_state(struct task_struct *p, unsigned int state)
2050{
2051 return try_to_wake_up(p, state, 0);
2052}
2053
2054/*
2055 * This function clears the sched_dl_entity static params.
2056 */
2057void __dl_clear_params(struct task_struct *p)
2058{
2059 struct sched_dl_entity *dl_se = &p->dl;
2060
2061 dl_se->dl_runtime = 0;
2062 dl_se->dl_deadline = 0;
2063 dl_se->dl_period = 0;
2064 dl_se->flags = 0;
2065 dl_se->dl_bw = 0;
2066
2067 dl_se->dl_throttled = 0;
2068 dl_se->dl_yielded = 0;
2069}
2070
2071/*
2072 * Perform scheduler related setup for a newly forked process p.
2073 * p is forked by current.
2074 *
2075 * __sched_fork() is basic setup used by init_idle() too:
2076 */
2077static void __sched_fork(unsigned long clone_flags, struct task_struct *p)
2078{
2079 p->on_rq = 0;
2080
2081 p->se.on_rq = 0;
2082 p->se.exec_start = 0;
2083 p->se.sum_exec_runtime = 0;
2084 p->se.prev_sum_exec_runtime = 0;
2085 p->se.nr_migrations = 0;
2086 p->se.vruntime = 0;
2087 INIT_LIST_HEAD(&p->se.group_node);
2088
2089#ifdef CONFIG_FAIR_GROUP_SCHED
2090 p->se.cfs_rq = NULL;
2091#endif
2092
2093#ifdef CONFIG_SCHEDSTATS
2094 /* Even if schedstat is disabled, there should not be garbage */
2095 memset(&p->se.statistics, 0, sizeof(p->se.statistics));
2096#endif
2097
2098 RB_CLEAR_NODE(&p->dl.rb_node);
2099 init_dl_task_timer(&p->dl);
2100 __dl_clear_params(p);
2101
2102 INIT_LIST_HEAD(&p->rt.run_list);
2103 p->rt.timeout = 0;
2104 p->rt.time_slice = sched_rr_timeslice;
2105 p->rt.on_rq = 0;
2106 p->rt.on_list = 0;
2107
2108#ifdef CONFIG_PREEMPT_NOTIFIERS
2109 INIT_HLIST_HEAD(&p->preempt_notifiers);
2110#endif
2111
2112#ifdef CONFIG_NUMA_BALANCING
2113 if (p->mm && atomic_read(&p->mm->mm_users) == 1) {
2114 p->mm->numa_next_scan = jiffies + msecs_to_jiffies(sysctl_numa_balancing_scan_delay);
2115 p->mm->numa_scan_seq = 0;
2116 }
2117
2118 if (clone_flags & CLONE_VM)
2119 p->numa_preferred_nid = current->numa_preferred_nid;
2120 else
2121 p->numa_preferred_nid = -1;
2122
2123 p->node_stamp = 0ULL;
2124 p->numa_scan_seq = p->mm ? p->mm->numa_scan_seq : 0;
2125 p->numa_scan_period = sysctl_numa_balancing_scan_delay;
2126 p->numa_work.next = &p->numa_work;
2127 p->numa_faults = NULL;
2128 p->last_task_numa_placement = 0;
2129 p->last_sum_exec_runtime = 0;
2130
2131 p->numa_group = NULL;
2132#endif /* CONFIG_NUMA_BALANCING */
2133}
2134
2135DEFINE_STATIC_KEY_FALSE(sched_numa_balancing);
2136
2137#ifdef CONFIG_NUMA_BALANCING
2138
2139void set_numabalancing_state(bool enabled)
2140{
2141 if (enabled)
2142 static_branch_enable(&sched_numa_balancing);
2143 else
2144 static_branch_disable(&sched_numa_balancing);
2145}
2146
2147#ifdef CONFIG_PROC_SYSCTL
2148int sysctl_numa_balancing(struct ctl_table *table, int write,
2149 void __user *buffer, size_t *lenp, loff_t *ppos)
2150{
2151 struct ctl_table t;
2152 int err;
2153 int state = static_branch_likely(&sched_numa_balancing);
2154
2155 if (write && !capable(CAP_SYS_ADMIN))
2156 return -EPERM;
2157
2158 t = *table;
2159 t.data = &state;
2160 err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos);
2161 if (err < 0)
2162 return err;
2163 if (write)
2164 set_numabalancing_state(state);
2165 return err;
2166}
2167#endif
2168#endif
2169
2170DEFINE_STATIC_KEY_FALSE(sched_schedstats);
2171
2172#ifdef CONFIG_SCHEDSTATS
2173static void set_schedstats(bool enabled)
2174{
2175 if (enabled)
2176 static_branch_enable(&sched_schedstats);
2177 else
2178 static_branch_disable(&sched_schedstats);
2179}
2180
2181void force_schedstat_enabled(void)
2182{
2183 if (!schedstat_enabled()) {
2184 pr_info("kernel profiling enabled schedstats, disable via kernel.sched_schedstats.\n");
2185 static_branch_enable(&sched_schedstats);
2186 }
2187}
2188
2189static int __init setup_schedstats(char *str)
2190{
2191 int ret = 0;
2192 if (!str)
2193 goto out;
2194
2195 if (!strcmp(str, "enable")) {
2196 set_schedstats(true);
2197 ret = 1;
2198 } else if (!strcmp(str, "disable")) {
2199 set_schedstats(false);
2200 ret = 1;
2201 }
2202out:
2203 if (!ret)
2204 pr_warn("Unable to parse schedstats=\n");
2205
2206 return ret;
2207}
2208__setup("schedstats=", setup_schedstats);
2209
2210#ifdef CONFIG_PROC_SYSCTL
2211int sysctl_schedstats(struct ctl_table *table, int write,
2212 void __user *buffer, size_t *lenp, loff_t *ppos)
2213{
2214 struct ctl_table t;
2215 int err;
2216 int state = static_branch_likely(&sched_schedstats);
2217
2218 if (write && !capable(CAP_SYS_ADMIN))
2219 return -EPERM;
2220
2221 t = *table;
2222 t.data = &state;
2223 err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos);
2224 if (err < 0)
2225 return err;
2226 if (write)
2227 set_schedstats(state);
2228 return err;
2229}
2230#endif
2231#endif
2232
2233/*
2234 * fork()/clone()-time setup:
2235 */
2236int sched_fork(unsigned long clone_flags, struct task_struct *p)
2237{
2238 unsigned long flags;
2239 int cpu = get_cpu();
2240
2241 __sched_fork(clone_flags, p);
2242 /*
2243 * We mark the process as running here. This guarantees that
2244 * nobody will actually run it, and a signal or other external
2245 * event cannot wake it up and insert it on the runqueue either.
2246 */
2247 p->state = TASK_RUNNING;
2248
2249 /*
2250 * Make sure we do not leak PI boosting priority to the child.
2251 */
2252 p->prio = current->normal_prio;
2253
2254 /*
2255 * Revert to default priority/policy on fork if requested.
2256 */
2257 if (unlikely(p->sched_reset_on_fork)) {
2258 if (task_has_dl_policy(p) || task_has_rt_policy(p)) {
2259 p->policy = SCHED_NORMAL;
2260 p->static_prio = NICE_TO_PRIO(0);
2261 p->rt_priority = 0;
2262 } else if (PRIO_TO_NICE(p->static_prio) < 0)
2263 p->static_prio = NICE_TO_PRIO(0);
2264
2265 p->prio = p->normal_prio = __normal_prio(p);
2266 set_load_weight(p);
2267
2268 /*
2269 * We don't need the reset flag anymore after the fork. It has
2270 * fulfilled its duty:
2271 */
2272 p->sched_reset_on_fork = 0;
2273 }
2274
2275 if (dl_prio(p->prio)) {
2276 put_cpu();
2277 return -EAGAIN;
2278 } else if (rt_prio(p->prio)) {
2279 p->sched_class = &rt_sched_class;
2280 } else {
2281 p->sched_class = &fair_sched_class;
2282 }
2283
2284 if (p->sched_class->task_fork)
2285 p->sched_class->task_fork(p);
2286
2287 /*
2288 * The child is not yet in the pid-hash so no cgroup attach races,
2289 * and the cgroup is pinned to this child due to cgroup_fork()
2290 * is ran before sched_fork().
2291 *
2292 * Silence PROVE_RCU.
2293 */
2294 raw_spin_lock_irqsave(&p->pi_lock, flags);
2295 set_task_cpu(p, cpu);
2296 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
2297
2298#ifdef CONFIG_SCHED_INFO
2299 if (likely(sched_info_on()))
2300 memset(&p->sched_info, 0, sizeof(p->sched_info));
2301#endif
2302#if defined(CONFIG_SMP)
2303 p->on_cpu = 0;
2304#endif
2305 init_task_preempt_count(p);
2306#ifdef CONFIG_SMP
2307 plist_node_init(&p->pushable_tasks, MAX_PRIO);
2308 RB_CLEAR_NODE(&p->pushable_dl_tasks);
2309#endif
2310
2311 put_cpu();
2312 return 0;
2313}
2314
2315unsigned long to_ratio(u64 period, u64 runtime)
2316{
2317 if (runtime == RUNTIME_INF)
2318 return 1ULL << 20;
2319
2320 /*
2321 * Doing this here saves a lot of checks in all
2322 * the calling paths, and returning zero seems
2323 * safe for them anyway.
2324 */
2325 if (period == 0)
2326 return 0;
2327
2328 return div64_u64(runtime << 20, period);
2329}
2330
2331#ifdef CONFIG_SMP
2332inline struct dl_bw *dl_bw_of(int i)
2333{
2334 RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(),
2335 "sched RCU must be held");
2336 return &cpu_rq(i)->rd->dl_bw;
2337}
2338
2339static inline int dl_bw_cpus(int i)
2340{
2341 struct root_domain *rd = cpu_rq(i)->rd;
2342 int cpus = 0;
2343
2344 RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(),
2345 "sched RCU must be held");
2346 for_each_cpu_and(i, rd->span, cpu_active_mask)
2347 cpus++;
2348
2349 return cpus;
2350}
2351#else
2352inline struct dl_bw *dl_bw_of(int i)
2353{
2354 return &cpu_rq(i)->dl.dl_bw;
2355}
2356
2357static inline int dl_bw_cpus(int i)
2358{
2359 return 1;
2360}
2361#endif
2362
2363/*
2364 * We must be sure that accepting a new task (or allowing changing the
2365 * parameters of an existing one) is consistent with the bandwidth
2366 * constraints. If yes, this function also accordingly updates the currently
2367 * allocated bandwidth to reflect the new situation.
2368 *
2369 * This function is called while holding p's rq->lock.
2370 *
2371 * XXX we should delay bw change until the task's 0-lag point, see
2372 * __setparam_dl().
2373 */
2374static int dl_overflow(struct task_struct *p, int policy,
2375 const struct sched_attr *attr)
2376{
2377
2378 struct dl_bw *dl_b = dl_bw_of(task_cpu(p));
2379 u64 period = attr->sched_period ?: attr->sched_deadline;
2380 u64 runtime = attr->sched_runtime;
2381 u64 new_bw = dl_policy(policy) ? to_ratio(period, runtime) : 0;
2382 int cpus, err = -1;
2383
2384 if (new_bw == p->dl.dl_bw)
2385 return 0;
2386
2387 /*
2388 * Either if a task, enters, leave, or stays -deadline but changes
2389 * its parameters, we may need to update accordingly the total
2390 * allocated bandwidth of the container.
2391 */
2392 raw_spin_lock(&dl_b->lock);
2393 cpus = dl_bw_cpus(task_cpu(p));
2394 if (dl_policy(policy) && !task_has_dl_policy(p) &&
2395 !__dl_overflow(dl_b, cpus, 0, new_bw)) {
2396 __dl_add(dl_b, new_bw);
2397 err = 0;
2398 } else if (dl_policy(policy) && task_has_dl_policy(p) &&
2399 !__dl_overflow(dl_b, cpus, p->dl.dl_bw, new_bw)) {
2400 __dl_clear(dl_b, p->dl.dl_bw);
2401 __dl_add(dl_b, new_bw);
2402 err = 0;
2403 } else if (!dl_policy(policy) && task_has_dl_policy(p)) {
2404 __dl_clear(dl_b, p->dl.dl_bw);
2405 err = 0;
2406 }
2407 raw_spin_unlock(&dl_b->lock);
2408
2409 return err;
2410}
2411
2412extern void init_dl_bw(struct dl_bw *dl_b);
2413
2414/*
2415 * wake_up_new_task - wake up a newly created task for the first time.
2416 *
2417 * This function will do some initial scheduler statistics housekeeping
2418 * that must be done for every newly created context, then puts the task
2419 * on the runqueue and wakes it.
2420 */
2421void wake_up_new_task(struct task_struct *p)
2422{
2423 unsigned long flags;
2424 struct rq *rq;
2425
2426 raw_spin_lock_irqsave(&p->pi_lock, flags);
2427 /* Initialize new task's runnable average */
2428 init_entity_runnable_average(&p->se);
2429#ifdef CONFIG_SMP
2430 /*
2431 * Fork balancing, do it here and not earlier because:
2432 * - cpus_allowed can change in the fork path
2433 * - any previously selected cpu might disappear through hotplug
2434 */
2435 set_task_cpu(p, select_task_rq(p, task_cpu(p), SD_BALANCE_FORK, 0));
2436#endif
2437
2438 rq = __task_rq_lock(p);
2439 activate_task(rq, p, 0);
2440 p->on_rq = TASK_ON_RQ_QUEUED;
2441 trace_sched_wakeup_new(p);
2442 check_preempt_curr(rq, p, WF_FORK);
2443#ifdef CONFIG_SMP
2444 if (p->sched_class->task_woken) {
2445 /*
2446 * Nothing relies on rq->lock after this, so its fine to
2447 * drop it.
2448 */
2449 lockdep_unpin_lock(&rq->lock);
2450 p->sched_class->task_woken(rq, p);
2451 lockdep_pin_lock(&rq->lock);
2452 }
2453#endif
2454 task_rq_unlock(rq, p, &flags);
2455}
2456
2457#ifdef CONFIG_PREEMPT_NOTIFIERS
2458
2459static struct static_key preempt_notifier_key = STATIC_KEY_INIT_FALSE;
2460
2461void preempt_notifier_inc(void)
2462{
2463 static_key_slow_inc(&preempt_notifier_key);
2464}
2465EXPORT_SYMBOL_GPL(preempt_notifier_inc);
2466
2467void preempt_notifier_dec(void)
2468{
2469 static_key_slow_dec(&preempt_notifier_key);
2470}
2471EXPORT_SYMBOL_GPL(preempt_notifier_dec);
2472
2473/**
2474 * preempt_notifier_register - tell me when current is being preempted & rescheduled
2475 * @notifier: notifier struct to register
2476 */
2477void preempt_notifier_register(struct preempt_notifier *notifier)
2478{
2479 if (!static_key_false(&preempt_notifier_key))
2480 WARN(1, "registering preempt_notifier while notifiers disabled\n");
2481
2482 hlist_add_head(¬ifier->link, ¤t->preempt_notifiers);
2483}
2484EXPORT_SYMBOL_GPL(preempt_notifier_register);
2485
2486/**
2487 * preempt_notifier_unregister - no longer interested in preemption notifications
2488 * @notifier: notifier struct to unregister
2489 *
2490 * This is *not* safe to call from within a preemption notifier.
2491 */
2492void preempt_notifier_unregister(struct preempt_notifier *notifier)
2493{
2494 hlist_del(¬ifier->link);
2495}
2496EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
2497
2498static void __fire_sched_in_preempt_notifiers(struct task_struct *curr)
2499{
2500 struct preempt_notifier *notifier;
2501
2502 hlist_for_each_entry(notifier, &curr->preempt_notifiers, link)
2503 notifier->ops->sched_in(notifier, raw_smp_processor_id());
2504}
2505
2506static __always_inline void fire_sched_in_preempt_notifiers(struct task_struct *curr)
2507{
2508 if (static_key_false(&preempt_notifier_key))
2509 __fire_sched_in_preempt_notifiers(curr);
2510}
2511
2512static void
2513__fire_sched_out_preempt_notifiers(struct task_struct *curr,
2514 struct task_struct *next)
2515{
2516 struct preempt_notifier *notifier;
2517
2518 hlist_for_each_entry(notifier, &curr->preempt_notifiers, link)
2519 notifier->ops->sched_out(notifier, next);
2520}
2521
2522static __always_inline void
2523fire_sched_out_preempt_notifiers(struct task_struct *curr,
2524 struct task_struct *next)
2525{
2526 if (static_key_false(&preempt_notifier_key))
2527 __fire_sched_out_preempt_notifiers(curr, next);
2528}
2529
2530#else /* !CONFIG_PREEMPT_NOTIFIERS */
2531
2532static inline void fire_sched_in_preempt_notifiers(struct task_struct *curr)
2533{
2534}
2535
2536static inline void
2537fire_sched_out_preempt_notifiers(struct task_struct *curr,
2538 struct task_struct *next)
2539{
2540}
2541
2542#endif /* CONFIG_PREEMPT_NOTIFIERS */
2543
2544/**
2545 * prepare_task_switch - prepare to switch tasks
2546 * @rq: the runqueue preparing to switch
2547 * @prev: the current task that is being switched out
2548 * @next: the task we are going to switch to.
2549 *
2550 * This is called with the rq lock held and interrupts off. It must
2551 * be paired with a subsequent finish_task_switch after the context
2552 * switch.
2553 *
2554 * prepare_task_switch sets up locking and calls architecture specific
2555 * hooks.
2556 */
2557static inline void
2558prepare_task_switch(struct rq *rq, struct task_struct *prev,
2559 struct task_struct *next)
2560{
2561 sched_info_switch(rq, prev, next);
2562 perf_event_task_sched_out(prev, next);
2563 fire_sched_out_preempt_notifiers(prev, next);
2564 prepare_lock_switch(rq, next);
2565 prepare_arch_switch(next);
2566}
2567
2568/**
2569 * finish_task_switch - clean up after a task-switch
2570 * @prev: the thread we just switched away from.
2571 *
2572 * finish_task_switch must be called after the context switch, paired
2573 * with a prepare_task_switch call before the context switch.
2574 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2575 * and do any other architecture-specific cleanup actions.
2576 *
2577 * Note that we may have delayed dropping an mm in context_switch(). If
2578 * so, we finish that here outside of the runqueue lock. (Doing it
2579 * with the lock held can cause deadlocks; see schedule() for
2580 * details.)
2581 *
2582 * The context switch have flipped the stack from under us and restored the
2583 * local variables which were saved when this task called schedule() in the
2584 * past. prev == current is still correct but we need to recalculate this_rq
2585 * because prev may have moved to another CPU.
2586 */
2587static struct rq *finish_task_switch(struct task_struct *prev)
2588 __releases(rq->lock)
2589{
2590 struct rq *rq = this_rq();
2591 struct mm_struct *mm = rq->prev_mm;
2592 long prev_state;
2593
2594 /*
2595 * The previous task will have left us with a preempt_count of 2
2596 * because it left us after:
2597 *
2598 * schedule()
2599 * preempt_disable(); // 1
2600 * __schedule()
2601 * raw_spin_lock_irq(&rq->lock) // 2
2602 *
2603 * Also, see FORK_PREEMPT_COUNT.
2604 */
2605 if (WARN_ONCE(preempt_count() != 2*PREEMPT_DISABLE_OFFSET,
2606 "corrupted preempt_count: %s/%d/0x%x\n",
2607 current->comm, current->pid, preempt_count()))
2608 preempt_count_set(FORK_PREEMPT_COUNT);
2609
2610 rq->prev_mm = NULL;
2611
2612 /*
2613 * A task struct has one reference for the use as "current".
2614 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2615 * schedule one last time. The schedule call will never return, and
2616 * the scheduled task must drop that reference.
2617 *
2618 * We must observe prev->state before clearing prev->on_cpu (in
2619 * finish_lock_switch), otherwise a concurrent wakeup can get prev
2620 * running on another CPU and we could rave with its RUNNING -> DEAD
2621 * transition, resulting in a double drop.
2622 */
2623 prev_state = prev->state;
2624 vtime_task_switch(prev);
2625 perf_event_task_sched_in(prev, current);
2626 finish_lock_switch(rq, prev);
2627 finish_arch_post_lock_switch();
2628
2629 fire_sched_in_preempt_notifiers(current);
2630 if (mm)
2631 mmdrop(mm);
2632 if (unlikely(prev_state == TASK_DEAD)) {
2633 if (prev->sched_class->task_dead)
2634 prev->sched_class->task_dead(prev);
2635
2636 /*
2637 * Remove function-return probe instances associated with this
2638 * task and put them back on the free list.
2639 */
2640 kprobe_flush_task(prev);
2641 put_task_struct(prev);
2642 }
2643
2644 tick_nohz_task_switch();
2645 return rq;
2646}
2647
2648#ifdef CONFIG_SMP
2649
2650/* rq->lock is NOT held, but preemption is disabled */
2651static void __balance_callback(struct rq *rq)
2652{
2653 struct callback_head *head, *next;
2654 void (*func)(struct rq *rq);
2655 unsigned long flags;
2656
2657 raw_spin_lock_irqsave(&rq->lock, flags);
2658 head = rq->balance_callback;
2659 rq->balance_callback = NULL;
2660 while (head) {
2661 func = (void (*)(struct rq *))head->func;
2662 next = head->next;
2663 head->next = NULL;
2664 head = next;
2665
2666 func(rq);
2667 }
2668 raw_spin_unlock_irqrestore(&rq->lock, flags);
2669}
2670
2671static inline void balance_callback(struct rq *rq)
2672{
2673 if (unlikely(rq->balance_callback))
2674 __balance_callback(rq);
2675}
2676
2677#else
2678
2679static inline void balance_callback(struct rq *rq)
2680{
2681}
2682
2683#endif
2684
2685/**
2686 * schedule_tail - first thing a freshly forked thread must call.
2687 * @prev: the thread we just switched away from.
2688 */
2689asmlinkage __visible void schedule_tail(struct task_struct *prev)
2690 __releases(rq->lock)
2691{
2692 struct rq *rq;
2693
2694 /*
2695 * New tasks start with FORK_PREEMPT_COUNT, see there and
2696 * finish_task_switch() for details.
2697 *
2698 * finish_task_switch() will drop rq->lock() and lower preempt_count
2699 * and the preempt_enable() will end up enabling preemption (on
2700 * PREEMPT_COUNT kernels).
2701 */
2702
2703 rq = finish_task_switch(prev);
2704 balance_callback(rq);
2705 preempt_enable();
2706
2707 if (current->set_child_tid)
2708 put_user(task_pid_vnr(current), current->set_child_tid);
2709}
2710
2711/*
2712 * context_switch - switch to the new MM and the new thread's register state.
2713 */
2714static __always_inline struct rq *
2715context_switch(struct rq *rq, struct task_struct *prev,
2716 struct task_struct *next)
2717{
2718 struct mm_struct *mm, *oldmm;
2719
2720 prepare_task_switch(rq, prev, next);
2721
2722 mm = next->mm;
2723 oldmm = prev->active_mm;
2724 /*
2725 * For paravirt, this is coupled with an exit in switch_to to
2726 * combine the page table reload and the switch backend into
2727 * one hypercall.
2728 */
2729 arch_start_context_switch(prev);
2730
2731 if (!mm) {
2732 next->active_mm = oldmm;
2733 atomic_inc(&oldmm->mm_count);
2734 enter_lazy_tlb(oldmm, next);
2735 } else
2736 switch_mm(oldmm, mm, next);
2737
2738 if (!prev->mm) {
2739 prev->active_mm = NULL;
2740 rq->prev_mm = oldmm;
2741 }
2742 /*
2743 * Since the runqueue lock will be released by the next
2744 * task (which is an invalid locking op but in the case
2745 * of the scheduler it's an obvious special-case), so we
2746 * do an early lockdep release here:
2747 */
2748 lockdep_unpin_lock(&rq->lock);
2749 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
2750
2751 /* Here we just switch the register state and the stack. */
2752 switch_to(prev, next, prev);
2753 barrier();
2754
2755 return finish_task_switch(prev);
2756}
2757
2758/*
2759 * nr_running and nr_context_switches:
2760 *
2761 * externally visible scheduler statistics: current number of runnable
2762 * threads, total number of context switches performed since bootup.
2763 */
2764unsigned long nr_running(void)
2765{
2766 unsigned long i, sum = 0;
2767
2768 for_each_online_cpu(i)
2769 sum += cpu_rq(i)->nr_running;
2770
2771 return sum;
2772}
2773
2774/*
2775 * Check if only the current task is running on the cpu.
2776 *
2777 * Caution: this function does not check that the caller has disabled
2778 * preemption, thus the result might have a time-of-check-to-time-of-use
2779 * race. The caller is responsible to use it correctly, for example:
2780 *
2781 * - from a non-preemptable section (of course)
2782 *
2783 * - from a thread that is bound to a single CPU
2784 *
2785 * - in a loop with very short iterations (e.g. a polling loop)
2786 */
2787bool single_task_running(void)
2788{
2789 return raw_rq()->nr_running == 1;
2790}
2791EXPORT_SYMBOL(single_task_running);
2792
2793unsigned long long nr_context_switches(void)
2794{
2795 int i;
2796 unsigned long long sum = 0;
2797
2798 for_each_possible_cpu(i)
2799 sum += cpu_rq(i)->nr_switches;
2800
2801 return sum;
2802}
2803
2804unsigned long nr_iowait(void)
2805{
2806 unsigned long i, sum = 0;
2807
2808 for_each_possible_cpu(i)
2809 sum += atomic_read(&cpu_rq(i)->nr_iowait);
2810
2811 return sum;
2812}
2813
2814unsigned long nr_iowait_cpu(int cpu)
2815{
2816 struct rq *this = cpu_rq(cpu);
2817 return atomic_read(&this->nr_iowait);
2818}
2819
2820void get_iowait_load(unsigned long *nr_waiters, unsigned long *load)
2821{
2822 struct rq *rq = this_rq();
2823 *nr_waiters = atomic_read(&rq->nr_iowait);
2824 *load = rq->load.weight;
2825}
2826
2827#ifdef CONFIG_SMP
2828
2829/*
2830 * sched_exec - execve() is a valuable balancing opportunity, because at
2831 * this point the task has the smallest effective memory and cache footprint.
2832 */
2833void sched_exec(void)
2834{
2835 struct task_struct *p = current;
2836 unsigned long flags;
2837 int dest_cpu;
2838
2839 raw_spin_lock_irqsave(&p->pi_lock, flags);
2840 dest_cpu = p->sched_class->select_task_rq(p, task_cpu(p), SD_BALANCE_EXEC, 0);
2841 if (dest_cpu == smp_processor_id())
2842 goto unlock;
2843
2844 if (likely(cpu_active(dest_cpu))) {
2845 struct migration_arg arg = { p, dest_cpu };
2846
2847 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
2848 stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg);
2849 return;
2850 }
2851unlock:
2852 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
2853}
2854
2855#endif
2856
2857DEFINE_PER_CPU(struct kernel_stat, kstat);
2858DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat);
2859
2860EXPORT_PER_CPU_SYMBOL(kstat);
2861EXPORT_PER_CPU_SYMBOL(kernel_cpustat);
2862
2863/*
2864 * Return accounted runtime for the task.
2865 * In case the task is currently running, return the runtime plus current's
2866 * pending runtime that have not been accounted yet.
2867 */
2868unsigned long long task_sched_runtime(struct task_struct *p)
2869{
2870 unsigned long flags;
2871 struct rq *rq;
2872 u64 ns;
2873
2874#if defined(CONFIG_64BIT) && defined(CONFIG_SMP)
2875 /*
2876 * 64-bit doesn't need locks to atomically read a 64bit value.
2877 * So we have a optimization chance when the task's delta_exec is 0.
2878 * Reading ->on_cpu is racy, but this is ok.
2879 *
2880 * If we race with it leaving cpu, we'll take a lock. So we're correct.
2881 * If we race with it entering cpu, unaccounted time is 0. This is
2882 * indistinguishable from the read occurring a few cycles earlier.
2883 * If we see ->on_cpu without ->on_rq, the task is leaving, and has
2884 * been accounted, so we're correct here as well.
2885 */
2886 if (!p->on_cpu || !task_on_rq_queued(p))
2887 return p->se.sum_exec_runtime;
2888#endif
2889
2890 rq = task_rq_lock(p, &flags);
2891 /*
2892 * Must be ->curr _and_ ->on_rq. If dequeued, we would
2893 * project cycles that may never be accounted to this
2894 * thread, breaking clock_gettime().
2895 */
2896 if (task_current(rq, p) && task_on_rq_queued(p)) {
2897 update_rq_clock(rq);
2898 p->sched_class->update_curr(rq);
2899 }
2900 ns = p->se.sum_exec_runtime;
2901 task_rq_unlock(rq, p, &flags);
2902
2903 return ns;
2904}
2905
2906/*
2907 * This function gets called by the timer code, with HZ frequency.
2908 * We call it with interrupts disabled.
2909 */
2910void scheduler_tick(void)
2911{
2912 int cpu = smp_processor_id();
2913 struct rq *rq = cpu_rq(cpu);
2914 struct task_struct *curr = rq->curr;
2915
2916 sched_clock_tick();
2917
2918 raw_spin_lock(&rq->lock);
2919 update_rq_clock(rq);
2920 curr->sched_class->task_tick(rq, curr, 0);
2921 update_cpu_load_active(rq);
2922 calc_global_load_tick(rq);
2923 raw_spin_unlock(&rq->lock);
2924
2925 perf_event_task_tick();
2926
2927#ifdef CONFIG_SMP
2928 rq->idle_balance = idle_cpu(cpu);
2929 trigger_load_balance(rq);
2930#endif
2931 rq_last_tick_reset(rq);
2932}
2933
2934#ifdef CONFIG_NO_HZ_FULL
2935/**
2936 * scheduler_tick_max_deferment
2937 *
2938 * Keep at least one tick per second when a single
2939 * active task is running because the scheduler doesn't
2940 * yet completely support full dynticks environment.
2941 *
2942 * This makes sure that uptime, CFS vruntime, load
2943 * balancing, etc... continue to move forward, even
2944 * with a very low granularity.
2945 *
2946 * Return: Maximum deferment in nanoseconds.
2947 */
2948u64 scheduler_tick_max_deferment(void)
2949{
2950 struct rq *rq = this_rq();
2951 unsigned long next, now = READ_ONCE(jiffies);
2952
2953 next = rq->last_sched_tick + HZ;
2954
2955 if (time_before_eq(next, now))
2956 return 0;
2957
2958 return jiffies_to_nsecs(next - now);
2959}
2960#endif
2961
2962#if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
2963 defined(CONFIG_PREEMPT_TRACER))
2964
2965void preempt_count_add(int val)
2966{
2967#ifdef CONFIG_DEBUG_PREEMPT
2968 /*
2969 * Underflow?
2970 */
2971 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
2972 return;
2973#endif
2974 __preempt_count_add(val);
2975#ifdef CONFIG_DEBUG_PREEMPT
2976 /*
2977 * Spinlock count overflowing soon?
2978 */
2979 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
2980 PREEMPT_MASK - 10);
2981#endif
2982 if (preempt_count() == val) {
2983 unsigned long ip = get_lock_parent_ip();
2984#ifdef CONFIG_DEBUG_PREEMPT
2985 current->preempt_disable_ip = ip;
2986#endif
2987 trace_preempt_off(CALLER_ADDR0, ip);
2988 }
2989}
2990EXPORT_SYMBOL(preempt_count_add);
2991NOKPROBE_SYMBOL(preempt_count_add);
2992
2993void preempt_count_sub(int val)
2994{
2995#ifdef CONFIG_DEBUG_PREEMPT
2996 /*
2997 * Underflow?
2998 */
2999 if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
3000 return;
3001 /*
3002 * Is the spinlock portion underflowing?
3003 */
3004 if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
3005 !(preempt_count() & PREEMPT_MASK)))
3006 return;
3007#endif
3008
3009 if (preempt_count() == val)
3010 trace_preempt_on(CALLER_ADDR0, get_lock_parent_ip());
3011 __preempt_count_sub(val);
3012}
3013EXPORT_SYMBOL(preempt_count_sub);
3014NOKPROBE_SYMBOL(preempt_count_sub);
3015
3016#endif
3017
3018/*
3019 * Print scheduling while atomic bug:
3020 */
3021static noinline void __schedule_bug(struct task_struct *prev)
3022{
3023 if (oops_in_progress)
3024 return;
3025
3026 printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
3027 prev->comm, prev->pid, preempt_count());
3028
3029 debug_show_held_locks(prev);
3030 print_modules();
3031 if (irqs_disabled())
3032 print_irqtrace_events(prev);
3033#ifdef CONFIG_DEBUG_PREEMPT
3034 if (in_atomic_preempt_off()) {
3035 pr_err("Preemption disabled at:");
3036 print_ip_sym(current->preempt_disable_ip);
3037 pr_cont("\n");
3038 }
3039#endif
3040 dump_stack();
3041 add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
3042}
3043
3044/*
3045 * Various schedule()-time debugging checks and statistics:
3046 */
3047static inline void schedule_debug(struct task_struct *prev)
3048{
3049#ifdef CONFIG_SCHED_STACK_END_CHECK
3050 BUG_ON(task_stack_end_corrupted(prev));
3051#endif
3052
3053 if (unlikely(in_atomic_preempt_off())) {
3054 __schedule_bug(prev);
3055 preempt_count_set(PREEMPT_DISABLED);
3056 }
3057 rcu_sleep_check();
3058
3059 profile_hit(SCHED_PROFILING, __builtin_return_address(0));
3060
3061 schedstat_inc(this_rq(), sched_count);
3062}
3063
3064/*
3065 * Pick up the highest-prio task:
3066 */
3067static inline struct task_struct *
3068pick_next_task(struct rq *rq, struct task_struct *prev)
3069{
3070 const struct sched_class *class = &fair_sched_class;
3071 struct task_struct *p;
3072
3073 /*
3074 * Optimization: we know that if all tasks are in
3075 * the fair class we can call that function directly:
3076 */
3077 if (likely(prev->sched_class == class &&
3078 rq->nr_running == rq->cfs.h_nr_running)) {
3079 p = fair_sched_class.pick_next_task(rq, prev);
3080 if (unlikely(p == RETRY_TASK))
3081 goto again;
3082
3083 /* assumes fair_sched_class->next == idle_sched_class */
3084 if (unlikely(!p))
3085 p = idle_sched_class.pick_next_task(rq, prev);
3086
3087 return p;
3088 }
3089
3090again:
3091 for_each_class(class) {
3092 p = class->pick_next_task(rq, prev);
3093 if (p) {
3094 if (unlikely(p == RETRY_TASK))
3095 goto again;
3096 return p;
3097 }
3098 }
3099
3100 BUG(); /* the idle class will always have a runnable task */
3101}
3102
3103/*
3104 * __schedule() is the main scheduler function.
3105 *
3106 * The main means of driving the scheduler and thus entering this function are:
3107 *
3108 * 1. Explicit blocking: mutex, semaphore, waitqueue, etc.
3109 *
3110 * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return
3111 * paths. For example, see arch/x86/entry_64.S.
3112 *
3113 * To drive preemption between tasks, the scheduler sets the flag in timer
3114 * interrupt handler scheduler_tick().
3115 *
3116 * 3. Wakeups don't really cause entry into schedule(). They add a
3117 * task to the run-queue and that's it.
3118 *
3119 * Now, if the new task added to the run-queue preempts the current
3120 * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets
3121 * called on the nearest possible occasion:
3122 *
3123 * - If the kernel is preemptible (CONFIG_PREEMPT=y):
3124 *
3125 * - in syscall or exception context, at the next outmost
3126 * preempt_enable(). (this might be as soon as the wake_up()'s
3127 * spin_unlock()!)
3128 *
3129 * - in IRQ context, return from interrupt-handler to
3130 * preemptible context
3131 *
3132 * - If the kernel is not preemptible (CONFIG_PREEMPT is not set)
3133 * then at the next:
3134 *
3135 * - cond_resched() call
3136 * - explicit schedule() call
3137 * - return from syscall or exception to user-space
3138 * - return from interrupt-handler to user-space
3139 *
3140 * WARNING: must be called with preemption disabled!
3141 */
3142static void __sched notrace __schedule(bool preempt)
3143{
3144 struct task_struct *prev, *next;
3145 unsigned long *switch_count;
3146 struct rq *rq;
3147 int cpu;
3148
3149 cpu = smp_processor_id();
3150 rq = cpu_rq(cpu);
3151 prev = rq->curr;
3152
3153 /*
3154 * do_exit() calls schedule() with preemption disabled as an exception;
3155 * however we must fix that up, otherwise the next task will see an
3156 * inconsistent (higher) preempt count.
3157 *
3158 * It also avoids the below schedule_debug() test from complaining
3159 * about this.
3160 */
3161 if (unlikely(prev->state == TASK_DEAD))
3162 preempt_enable_no_resched_notrace();
3163
3164 schedule_debug(prev);
3165
3166 if (sched_feat(HRTICK))
3167 hrtick_clear(rq);
3168
3169 local_irq_disable();
3170 rcu_note_context_switch();
3171
3172 /*
3173 * Make sure that signal_pending_state()->signal_pending() below
3174 * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE)
3175 * done by the caller to avoid the race with signal_wake_up().
3176 */
3177 smp_mb__before_spinlock();
3178 raw_spin_lock(&rq->lock);
3179 lockdep_pin_lock(&rq->lock);
3180
3181 rq->clock_skip_update <<= 1; /* promote REQ to ACT */
3182
3183 switch_count = &prev->nivcsw;
3184 if (!preempt && prev->state) {
3185 if (unlikely(signal_pending_state(prev->state, prev))) {
3186 prev->state = TASK_RUNNING;
3187 } else {
3188 deactivate_task(rq, prev, DEQUEUE_SLEEP);
3189 prev->on_rq = 0;
3190
3191 /*
3192 * If a worker went to sleep, notify and ask workqueue
3193 * whether it wants to wake up a task to maintain
3194 * concurrency.
3195 */
3196 if (prev->flags & PF_WQ_WORKER) {
3197 struct task_struct *to_wakeup;
3198
3199 to_wakeup = wq_worker_sleeping(prev);
3200 if (to_wakeup)
3201 try_to_wake_up_local(to_wakeup);
3202 }
3203 }
3204 switch_count = &prev->nvcsw;
3205 }
3206
3207 if (task_on_rq_queued(prev))
3208 update_rq_clock(rq);
3209
3210 next = pick_next_task(rq, prev);
3211 clear_tsk_need_resched(prev);
3212 clear_preempt_need_resched();
3213 rq->clock_skip_update = 0;
3214
3215 if (likely(prev != next)) {
3216 rq->nr_switches++;
3217 rq->curr = next;
3218 ++*switch_count;
3219
3220 trace_sched_switch(preempt, prev, next);
3221 rq = context_switch(rq, prev, next); /* unlocks the rq */
3222 } else {
3223 lockdep_unpin_lock(&rq->lock);
3224 raw_spin_unlock_irq(&rq->lock);
3225 }
3226
3227 balance_callback(rq);
3228}
3229STACK_FRAME_NON_STANDARD(__schedule); /* switch_to() */
3230
3231static inline void sched_submit_work(struct task_struct *tsk)
3232{
3233 if (!tsk->state || tsk_is_pi_blocked(tsk))
3234 return;
3235 /*
3236 * If we are going to sleep and we have plugged IO queued,
3237 * make sure to submit it to avoid deadlocks.
3238 */
3239 if (blk_needs_flush_plug(tsk))
3240 blk_schedule_flush_plug(tsk);
3241}
3242
3243asmlinkage __visible void __sched schedule(void)
3244{
3245 struct task_struct *tsk = current;
3246
3247 sched_submit_work(tsk);
3248 do {
3249 preempt_disable();
3250 __schedule(false);
3251 sched_preempt_enable_no_resched();
3252 } while (need_resched());
3253}
3254EXPORT_SYMBOL(schedule);
3255
3256#ifdef CONFIG_CONTEXT_TRACKING
3257asmlinkage __visible void __sched schedule_user(void)
3258{
3259 /*
3260 * If we come here after a random call to set_need_resched(),
3261 * or we have been woken up remotely but the IPI has not yet arrived,
3262 * we haven't yet exited the RCU idle mode. Do it here manually until
3263 * we find a better solution.
3264 *
3265 * NB: There are buggy callers of this function. Ideally we
3266 * should warn if prev_state != CONTEXT_USER, but that will trigger
3267 * too frequently to make sense yet.
3268 */
3269 enum ctx_state prev_state = exception_enter();
3270 schedule();
3271 exception_exit(prev_state);
3272}
3273#endif
3274
3275/**
3276 * schedule_preempt_disabled - called with preemption disabled
3277 *
3278 * Returns with preemption disabled. Note: preempt_count must be 1
3279 */
3280void __sched schedule_preempt_disabled(void)
3281{
3282 sched_preempt_enable_no_resched();
3283 schedule();
3284 preempt_disable();
3285}
3286
3287static void __sched notrace preempt_schedule_common(void)
3288{
3289 do {
3290 preempt_disable_notrace();
3291 __schedule(true);
3292 preempt_enable_no_resched_notrace();
3293
3294 /*
3295 * Check again in case we missed a preemption opportunity
3296 * between schedule and now.
3297 */
3298 } while (need_resched());
3299}
3300
3301#ifdef CONFIG_PREEMPT
3302/*
3303 * this is the entry point to schedule() from in-kernel preemption
3304 * off of preempt_enable. Kernel preemptions off return from interrupt
3305 * occur there and call schedule directly.
3306 */
3307asmlinkage __visible void __sched notrace preempt_schedule(void)
3308{
3309 /*
3310 * If there is a non-zero preempt_count or interrupts are disabled,
3311 * we do not want to preempt the current task. Just return..
3312 */
3313 if (likely(!preemptible()))
3314 return;
3315
3316 preempt_schedule_common();
3317}
3318NOKPROBE_SYMBOL(preempt_schedule);
3319EXPORT_SYMBOL(preempt_schedule);
3320
3321/**
3322 * preempt_schedule_notrace - preempt_schedule called by tracing
3323 *
3324 * The tracing infrastructure uses preempt_enable_notrace to prevent
3325 * recursion and tracing preempt enabling caused by the tracing
3326 * infrastructure itself. But as tracing can happen in areas coming
3327 * from userspace or just about to enter userspace, a preempt enable
3328 * can occur before user_exit() is called. This will cause the scheduler
3329 * to be called when the system is still in usermode.
3330 *
3331 * To prevent this, the preempt_enable_notrace will use this function
3332 * instead of preempt_schedule() to exit user context if needed before
3333 * calling the scheduler.
3334 */
3335asmlinkage __visible void __sched notrace preempt_schedule_notrace(void)
3336{
3337 enum ctx_state prev_ctx;
3338
3339 if (likely(!preemptible()))
3340 return;
3341
3342 do {
3343 preempt_disable_notrace();
3344 /*
3345 * Needs preempt disabled in case user_exit() is traced
3346 * and the tracer calls preempt_enable_notrace() causing
3347 * an infinite recursion.
3348 */
3349 prev_ctx = exception_enter();
3350 __schedule(true);
3351 exception_exit(prev_ctx);
3352
3353 preempt_enable_no_resched_notrace();
3354 } while (need_resched());
3355}
3356EXPORT_SYMBOL_GPL(preempt_schedule_notrace);
3357
3358#endif /* CONFIG_PREEMPT */
3359
3360/*
3361 * this is the entry point to schedule() from kernel preemption
3362 * off of irq context.
3363 * Note, that this is called and return with irqs disabled. This will
3364 * protect us against recursive calling from irq.
3365 */
3366asmlinkage __visible void __sched preempt_schedule_irq(void)
3367{
3368 enum ctx_state prev_state;
3369
3370 /* Catch callers which need to be fixed */
3371 BUG_ON(preempt_count() || !irqs_disabled());
3372
3373 prev_state = exception_enter();
3374
3375 do {
3376 preempt_disable();
3377 local_irq_enable();
3378 __schedule(true);
3379 local_irq_disable();
3380 sched_preempt_enable_no_resched();
3381 } while (need_resched());
3382
3383 exception_exit(prev_state);
3384}
3385
3386int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags,
3387 void *key)
3388{
3389 return try_to_wake_up(curr->private, mode, wake_flags);
3390}
3391EXPORT_SYMBOL(default_wake_function);
3392
3393#ifdef CONFIG_RT_MUTEXES
3394
3395/*
3396 * rt_mutex_setprio - set the current priority of a task
3397 * @p: task
3398 * @prio: prio value (kernel-internal form)
3399 *
3400 * This function changes the 'effective' priority of a task. It does
3401 * not touch ->normal_prio like __setscheduler().
3402 *
3403 * Used by the rt_mutex code to implement priority inheritance
3404 * logic. Call site only calls if the priority of the task changed.
3405 */
3406void rt_mutex_setprio(struct task_struct *p, int prio)
3407{
3408 int oldprio, queued, running, queue_flag = DEQUEUE_SAVE | DEQUEUE_MOVE;
3409 struct rq *rq;
3410 const struct sched_class *prev_class;
3411
3412 BUG_ON(prio > MAX_PRIO);
3413
3414 rq = __task_rq_lock(p);
3415
3416 /*
3417 * Idle task boosting is a nono in general. There is one
3418 * exception, when PREEMPT_RT and NOHZ is active:
3419 *
3420 * The idle task calls get_next_timer_interrupt() and holds
3421 * the timer wheel base->lock on the CPU and another CPU wants
3422 * to access the timer (probably to cancel it). We can safely
3423 * ignore the boosting request, as the idle CPU runs this code
3424 * with interrupts disabled and will complete the lock
3425 * protected section without being interrupted. So there is no
3426 * real need to boost.
3427 */
3428 if (unlikely(p == rq->idle)) {
3429 WARN_ON(p != rq->curr);
3430 WARN_ON(p->pi_blocked_on);
3431 goto out_unlock;
3432 }
3433
3434 trace_sched_pi_setprio(p, prio);
3435 oldprio = p->prio;
3436
3437 if (oldprio == prio)
3438 queue_flag &= ~DEQUEUE_MOVE;
3439
3440 prev_class = p->sched_class;
3441 queued = task_on_rq_queued(p);
3442 running = task_current(rq, p);
3443 if (queued)
3444 dequeue_task(rq, p, queue_flag);
3445 if (running)
3446 put_prev_task(rq, p);
3447
3448 /*
3449 * Boosting condition are:
3450 * 1. -rt task is running and holds mutex A
3451 * --> -dl task blocks on mutex A
3452 *
3453 * 2. -dl task is running and holds mutex A
3454 * --> -dl task blocks on mutex A and could preempt the
3455 * running task
3456 */
3457 if (dl_prio(prio)) {
3458 struct task_struct *pi_task = rt_mutex_get_top_task(p);
3459 if (!dl_prio(p->normal_prio) ||
3460 (pi_task && dl_entity_preempt(&pi_task->dl, &p->dl))) {
3461 p->dl.dl_boosted = 1;
3462 queue_flag |= ENQUEUE_REPLENISH;
3463 } else
3464 p->dl.dl_boosted = 0;
3465 p->sched_class = &dl_sched_class;
3466 } else if (rt_prio(prio)) {
3467 if (dl_prio(oldprio))
3468 p->dl.dl_boosted = 0;
3469 if (oldprio < prio)
3470 queue_flag |= ENQUEUE_HEAD;
3471 p->sched_class = &rt_sched_class;
3472 } else {
3473 if (dl_prio(oldprio))
3474 p->dl.dl_boosted = 0;
3475 if (rt_prio(oldprio))
3476 p->rt.timeout = 0;
3477 p->sched_class = &fair_sched_class;
3478 }
3479
3480 p->prio = prio;
3481
3482 if (running)
3483 p->sched_class->set_curr_task(rq);
3484 if (queued)
3485 enqueue_task(rq, p, queue_flag);
3486
3487 check_class_changed(rq, p, prev_class, oldprio);
3488out_unlock:
3489 preempt_disable(); /* avoid rq from going away on us */
3490 __task_rq_unlock(rq);
3491
3492 balance_callback(rq);
3493 preempt_enable();
3494}
3495#endif
3496
3497void set_user_nice(struct task_struct *p, long nice)
3498{
3499 int old_prio, delta, queued;
3500 unsigned long flags;
3501 struct rq *rq;
3502
3503 if (task_nice(p) == nice || nice < MIN_NICE || nice > MAX_NICE)
3504 return;
3505 /*
3506 * We have to be careful, if called from sys_setpriority(),
3507 * the task might be in the middle of scheduling on another CPU.
3508 */
3509 rq = task_rq_lock(p, &flags);
3510 /*
3511 * The RT priorities are set via sched_setscheduler(), but we still
3512 * allow the 'normal' nice value to be set - but as expected
3513 * it wont have any effect on scheduling until the task is
3514 * SCHED_DEADLINE, SCHED_FIFO or SCHED_RR:
3515 */
3516 if (task_has_dl_policy(p) || task_has_rt_policy(p)) {
3517 p->static_prio = NICE_TO_PRIO(nice);
3518 goto out_unlock;
3519 }
3520 queued = task_on_rq_queued(p);
3521 if (queued)
3522 dequeue_task(rq, p, DEQUEUE_SAVE);
3523
3524 p->static_prio = NICE_TO_PRIO(nice);
3525 set_load_weight(p);
3526 old_prio = p->prio;
3527 p->prio = effective_prio(p);
3528 delta = p->prio - old_prio;
3529
3530 if (queued) {
3531 enqueue_task(rq, p, ENQUEUE_RESTORE);
3532 /*
3533 * If the task increased its priority or is running and
3534 * lowered its priority, then reschedule its CPU:
3535 */
3536 if (delta < 0 || (delta > 0 && task_running(rq, p)))
3537 resched_curr(rq);
3538 }
3539out_unlock:
3540 task_rq_unlock(rq, p, &flags);
3541}
3542EXPORT_SYMBOL(set_user_nice);
3543
3544/*
3545 * can_nice - check if a task can reduce its nice value
3546 * @p: task
3547 * @nice: nice value
3548 */
3549int can_nice(const struct task_struct *p, const int nice)
3550{
3551 /* convert nice value [19,-20] to rlimit style value [1,40] */
3552 int nice_rlim = nice_to_rlimit(nice);
3553
3554 return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) ||
3555 capable(CAP_SYS_NICE));
3556}
3557
3558#ifdef __ARCH_WANT_SYS_NICE
3559
3560/*
3561 * sys_nice - change the priority of the current process.
3562 * @increment: priority increment
3563 *
3564 * sys_setpriority is a more generic, but much slower function that
3565 * does similar things.
3566 */
3567SYSCALL_DEFINE1(nice, int, increment)
3568{
3569 long nice, retval;
3570
3571 /*
3572 * Setpriority might change our priority at the same moment.
3573 * We don't have to worry. Conceptually one call occurs first
3574 * and we have a single winner.
3575 */
3576 increment = clamp(increment, -NICE_WIDTH, NICE_WIDTH);
3577 nice = task_nice(current) + increment;
3578
3579 nice = clamp_val(nice, MIN_NICE, MAX_NICE);
3580 if (increment < 0 && !can_nice(current, nice))
3581 return -EPERM;
3582
3583 retval = security_task_setnice(current, nice);
3584 if (retval)
3585 return retval;
3586
3587 set_user_nice(current, nice);
3588 return 0;
3589}
3590
3591#endif
3592
3593/**
3594 * task_prio - return the priority value of a given task.
3595 * @p: the task in question.
3596 *
3597 * Return: The priority value as seen by users in /proc.
3598 * RT tasks are offset by -200. Normal tasks are centered
3599 * around 0, value goes from -16 to +15.
3600 */
3601int task_prio(const struct task_struct *p)
3602{
3603 return p->prio - MAX_RT_PRIO;
3604}
3605
3606/**
3607 * idle_cpu - is a given cpu idle currently?
3608 * @cpu: the processor in question.
3609 *
3610 * Return: 1 if the CPU is currently idle. 0 otherwise.
3611 */
3612int idle_cpu(int cpu)
3613{
3614 struct rq *rq = cpu_rq(cpu);
3615
3616 if (rq->curr != rq->idle)
3617 return 0;
3618
3619 if (rq->nr_running)
3620 return 0;
3621
3622#ifdef CONFIG_SMP
3623 if (!llist_empty(&rq->wake_list))
3624 return 0;
3625#endif
3626
3627 return 1;
3628}
3629
3630/**
3631 * idle_task - return the idle task for a given cpu.
3632 * @cpu: the processor in question.
3633 *
3634 * Return: The idle task for the cpu @cpu.
3635 */
3636struct task_struct *idle_task(int cpu)
3637{
3638 return cpu_rq(cpu)->idle;
3639}
3640
3641/**
3642 * find_process_by_pid - find a process with a matching PID value.
3643 * @pid: the pid in question.
3644 *
3645 * The task of @pid, if found. %NULL otherwise.
3646 */
3647static struct task_struct *find_process_by_pid(pid_t pid)
3648{
3649 return pid ? find_task_by_vpid(pid) : current;
3650}
3651
3652/*
3653 * This function initializes the sched_dl_entity of a newly becoming
3654 * SCHED_DEADLINE task.
3655 *
3656 * Only the static values are considered here, the actual runtime and the
3657 * absolute deadline will be properly calculated when the task is enqueued
3658 * for the first time with its new policy.
3659 */
3660static void
3661__setparam_dl(struct task_struct *p, const struct sched_attr *attr)
3662{
3663 struct sched_dl_entity *dl_se = &p->dl;
3664
3665 dl_se->dl_runtime = attr->sched_runtime;
3666 dl_se->dl_deadline = attr->sched_deadline;
3667 dl_se->dl_period = attr->sched_period ?: dl_se->dl_deadline;
3668 dl_se->flags = attr->sched_flags;
3669 dl_se->dl_bw = to_ratio(dl_se->dl_period, dl_se->dl_runtime);
3670
3671 /*
3672 * Changing the parameters of a task is 'tricky' and we're not doing
3673 * the correct thing -- also see task_dead_dl() and switched_from_dl().
3674 *
3675 * What we SHOULD do is delay the bandwidth release until the 0-lag
3676 * point. This would include retaining the task_struct until that time
3677 * and change dl_overflow() to not immediately decrement the current
3678 * amount.
3679 *
3680 * Instead we retain the current runtime/deadline and let the new
3681 * parameters take effect after the current reservation period lapses.
3682 * This is safe (albeit pessimistic) because the 0-lag point is always
3683 * before the current scheduling deadline.
3684 *
3685 * We can still have temporary overloads because we do not delay the
3686 * change in bandwidth until that time; so admission control is
3687 * not on the safe side. It does however guarantee tasks will never
3688 * consume more than promised.
3689 */
3690}
3691
3692/*
3693 * sched_setparam() passes in -1 for its policy, to let the functions
3694 * it calls know not to change it.
3695 */
3696#define SETPARAM_POLICY -1
3697
3698static void __setscheduler_params(struct task_struct *p,
3699 const struct sched_attr *attr)
3700{
3701 int policy = attr->sched_policy;
3702
3703 if (policy == SETPARAM_POLICY)
3704 policy = p->policy;
3705
3706 p->policy = policy;
3707
3708 if (dl_policy(policy))
3709 __setparam_dl(p, attr);
3710 else if (fair_policy(policy))
3711 p->static_prio = NICE_TO_PRIO(attr->sched_nice);
3712
3713 /*
3714 * __sched_setscheduler() ensures attr->sched_priority == 0 when
3715 * !rt_policy. Always setting this ensures that things like
3716 * getparam()/getattr() don't report silly values for !rt tasks.
3717 */
3718 p->rt_priority = attr->sched_priority;
3719 p->normal_prio = normal_prio(p);
3720 set_load_weight(p);
3721}
3722
3723/* Actually do priority change: must hold pi & rq lock. */
3724static void __setscheduler(struct rq *rq, struct task_struct *p,
3725 const struct sched_attr *attr, bool keep_boost)
3726{
3727 __setscheduler_params(p, attr);
3728
3729 /*
3730 * Keep a potential priority boosting if called from
3731 * sched_setscheduler().
3732 */
3733 if (keep_boost)
3734 p->prio = rt_mutex_get_effective_prio(p, normal_prio(p));
3735 else
3736 p->prio = normal_prio(p);
3737
3738 if (dl_prio(p->prio))
3739 p->sched_class = &dl_sched_class;
3740 else if (rt_prio(p->prio))
3741 p->sched_class = &rt_sched_class;
3742 else
3743 p->sched_class = &fair_sched_class;
3744}
3745
3746static void
3747__getparam_dl(struct task_struct *p, struct sched_attr *attr)
3748{
3749 struct sched_dl_entity *dl_se = &p->dl;
3750
3751 attr->sched_priority = p->rt_priority;
3752 attr->sched_runtime = dl_se->dl_runtime;
3753 attr->sched_deadline = dl_se->dl_deadline;
3754 attr->sched_period = dl_se->dl_period;
3755 attr->sched_flags = dl_se->flags;
3756}
3757
3758/*
3759 * This function validates the new parameters of a -deadline task.
3760 * We ask for the deadline not being zero, and greater or equal
3761 * than the runtime, as well as the period of being zero or
3762 * greater than deadline. Furthermore, we have to be sure that
3763 * user parameters are above the internal resolution of 1us (we
3764 * check sched_runtime only since it is always the smaller one) and
3765 * below 2^63 ns (we have to check both sched_deadline and
3766 * sched_period, as the latter can be zero).
3767 */
3768static bool
3769__checkparam_dl(const struct sched_attr *attr)
3770{
3771 /* deadline != 0 */
3772 if (attr->sched_deadline == 0)
3773 return false;
3774
3775 /*
3776 * Since we truncate DL_SCALE bits, make sure we're at least
3777 * that big.
3778 */
3779 if (attr->sched_runtime < (1ULL << DL_SCALE))
3780 return false;
3781
3782 /*
3783 * Since we use the MSB for wrap-around and sign issues, make
3784 * sure it's not set (mind that period can be equal to zero).
3785 */
3786 if (attr->sched_deadline & (1ULL << 63) ||
3787 attr->sched_period & (1ULL << 63))
3788 return false;
3789
3790 /* runtime <= deadline <= period (if period != 0) */
3791 if ((attr->sched_period != 0 &&
3792 attr->sched_period < attr->sched_deadline) ||
3793 attr->sched_deadline < attr->sched_runtime)
3794 return false;
3795
3796 return true;
3797}
3798
3799/*
3800 * check the target process has a UID that matches the current process's
3801 */
3802static bool check_same_owner(struct task_struct *p)
3803{
3804 const struct cred *cred = current_cred(), *pcred;
3805 bool match;
3806
3807 rcu_read_lock();
3808 pcred = __task_cred(p);
3809 match = (uid_eq(cred->euid, pcred->euid) ||
3810 uid_eq(cred->euid, pcred->uid));
3811 rcu_read_unlock();
3812 return match;
3813}
3814
3815static bool dl_param_changed(struct task_struct *p,
3816 const struct sched_attr *attr)
3817{
3818 struct sched_dl_entity *dl_se = &p->dl;
3819
3820 if (dl_se->dl_runtime != attr->sched_runtime ||
3821 dl_se->dl_deadline != attr->sched_deadline ||
3822 dl_se->dl_period != attr->sched_period ||
3823 dl_se->flags != attr->sched_flags)
3824 return true;
3825
3826 return false;
3827}
3828
3829static int __sched_setscheduler(struct task_struct *p,
3830 const struct sched_attr *attr,
3831 bool user, bool pi)
3832{
3833 int newprio = dl_policy(attr->sched_policy) ? MAX_DL_PRIO - 1 :
3834 MAX_RT_PRIO - 1 - attr->sched_priority;
3835 int retval, oldprio, oldpolicy = -1, queued, running;
3836 int new_effective_prio, policy = attr->sched_policy;
3837 unsigned long flags;
3838 const struct sched_class *prev_class;
3839 struct rq *rq;
3840 int reset_on_fork;
3841 int queue_flags = DEQUEUE_SAVE | DEQUEUE_MOVE;
3842
3843 /* may grab non-irq protected spin_locks */
3844 BUG_ON(in_interrupt());
3845recheck:
3846 /* double check policy once rq lock held */
3847 if (policy < 0) {
3848 reset_on_fork = p->sched_reset_on_fork;
3849 policy = oldpolicy = p->policy;
3850 } else {
3851 reset_on_fork = !!(attr->sched_flags & SCHED_FLAG_RESET_ON_FORK);
3852
3853 if (!valid_policy(policy))
3854 return -EINVAL;
3855 }
3856
3857 if (attr->sched_flags & ~(SCHED_FLAG_RESET_ON_FORK))
3858 return -EINVAL;
3859
3860 /*
3861 * Valid priorities for SCHED_FIFO and SCHED_RR are
3862 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
3863 * SCHED_BATCH and SCHED_IDLE is 0.
3864 */
3865 if ((p->mm && attr->sched_priority > MAX_USER_RT_PRIO-1) ||
3866 (!p->mm && attr->sched_priority > MAX_RT_PRIO-1))
3867 return -EINVAL;
3868 if ((dl_policy(policy) && !__checkparam_dl(attr)) ||
3869 (rt_policy(policy) != (attr->sched_priority != 0)))
3870 return -EINVAL;
3871
3872 /*
3873 * Allow unprivileged RT tasks to decrease priority:
3874 */
3875 if (user && !capable(CAP_SYS_NICE)) {
3876 if (fair_policy(policy)) {
3877 if (attr->sched_nice < task_nice(p) &&
3878 !can_nice(p, attr->sched_nice))
3879 return -EPERM;
3880 }
3881
3882 if (rt_policy(policy)) {
3883 unsigned long rlim_rtprio =
3884 task_rlimit(p, RLIMIT_RTPRIO);
3885
3886 /* can't set/change the rt policy */
3887 if (policy != p->policy && !rlim_rtprio)
3888 return -EPERM;
3889
3890 /* can't increase priority */
3891 if (attr->sched_priority > p->rt_priority &&
3892 attr->sched_priority > rlim_rtprio)
3893 return -EPERM;
3894 }
3895
3896 /*
3897 * Can't set/change SCHED_DEADLINE policy at all for now
3898 * (safest behavior); in the future we would like to allow
3899 * unprivileged DL tasks to increase their relative deadline
3900 * or reduce their runtime (both ways reducing utilization)
3901 */
3902 if (dl_policy(policy))
3903 return -EPERM;
3904
3905 /*
3906 * Treat SCHED_IDLE as nice 20. Only allow a switch to
3907 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
3908 */
3909 if (idle_policy(p->policy) && !idle_policy(policy)) {
3910 if (!can_nice(p, task_nice(p)))
3911 return -EPERM;
3912 }
3913
3914 /* can't change other user's priorities */
3915 if (!check_same_owner(p))
3916 return -EPERM;
3917
3918 /* Normal users shall not reset the sched_reset_on_fork flag */
3919 if (p->sched_reset_on_fork && !reset_on_fork)
3920 return -EPERM;
3921 }
3922
3923 if (user) {
3924 retval = security_task_setscheduler(p);
3925 if (retval)
3926 return retval;
3927 }
3928
3929 /*
3930 * make sure no PI-waiters arrive (or leave) while we are
3931 * changing the priority of the task:
3932 *
3933 * To be able to change p->policy safely, the appropriate
3934 * runqueue lock must be held.
3935 */
3936 rq = task_rq_lock(p, &flags);
3937
3938 /*
3939 * Changing the policy of the stop threads its a very bad idea
3940 */
3941 if (p == rq->stop) {
3942 task_rq_unlock(rq, p, &flags);
3943 return -EINVAL;
3944 }
3945
3946 /*
3947 * If not changing anything there's no need to proceed further,
3948 * but store a possible modification of reset_on_fork.
3949 */
3950 if (unlikely(policy == p->policy)) {
3951 if (fair_policy(policy) && attr->sched_nice != task_nice(p))
3952 goto change;
3953 if (rt_policy(policy) && attr->sched_priority != p->rt_priority)
3954 goto change;
3955 if (dl_policy(policy) && dl_param_changed(p, attr))
3956 goto change;
3957
3958 p->sched_reset_on_fork = reset_on_fork;
3959 task_rq_unlock(rq, p, &flags);
3960 return 0;
3961 }
3962change:
3963
3964 if (user) {
3965#ifdef CONFIG_RT_GROUP_SCHED
3966 /*
3967 * Do not allow realtime tasks into groups that have no runtime
3968 * assigned.
3969 */
3970 if (rt_bandwidth_enabled() && rt_policy(policy) &&
3971 task_group(p)->rt_bandwidth.rt_runtime == 0 &&
3972 !task_group_is_autogroup(task_group(p))) {
3973 task_rq_unlock(rq, p, &flags);
3974 return -EPERM;
3975 }
3976#endif
3977#ifdef CONFIG_SMP
3978 if (dl_bandwidth_enabled() && dl_policy(policy)) {
3979 cpumask_t *span = rq->rd->span;
3980
3981 /*
3982 * Don't allow tasks with an affinity mask smaller than
3983 * the entire root_domain to become SCHED_DEADLINE. We
3984 * will also fail if there's no bandwidth available.
3985 */
3986 if (!cpumask_subset(span, &p->cpus_allowed) ||
3987 rq->rd->dl_bw.bw == 0) {
3988 task_rq_unlock(rq, p, &flags);
3989 return -EPERM;
3990 }
3991 }
3992#endif
3993 }
3994
3995 /* recheck policy now with rq lock held */
3996 if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
3997 policy = oldpolicy = -1;
3998 task_rq_unlock(rq, p, &flags);
3999 goto recheck;
4000 }
4001
4002 /*
4003 * If setscheduling to SCHED_DEADLINE (or changing the parameters
4004 * of a SCHED_DEADLINE task) we need to check if enough bandwidth
4005 * is available.
4006 */
4007 if ((dl_policy(policy) || dl_task(p)) && dl_overflow(p, policy, attr)) {
4008 task_rq_unlock(rq, p, &flags);
4009 return -EBUSY;
4010 }
4011
4012 p->sched_reset_on_fork = reset_on_fork;
4013 oldprio = p->prio;
4014
4015 if (pi) {
4016 /*
4017 * Take priority boosted tasks into account. If the new
4018 * effective priority is unchanged, we just store the new
4019 * normal parameters and do not touch the scheduler class and
4020 * the runqueue. This will be done when the task deboost
4021 * itself.
4022 */
4023 new_effective_prio = rt_mutex_get_effective_prio(p, newprio);
4024 if (new_effective_prio == oldprio)
4025 queue_flags &= ~DEQUEUE_MOVE;
4026 }
4027
4028 queued = task_on_rq_queued(p);
4029 running = task_current(rq, p);
4030 if (queued)
4031 dequeue_task(rq, p, queue_flags);
4032 if (running)
4033 put_prev_task(rq, p);
4034
4035 prev_class = p->sched_class;
4036 __setscheduler(rq, p, attr, pi);
4037
4038 if (running)
4039 p->sched_class->set_curr_task(rq);
4040 if (queued) {
4041 /*
4042 * We enqueue to tail when the priority of a task is
4043 * increased (user space view).
4044 */
4045 if (oldprio < p->prio)
4046 queue_flags |= ENQUEUE_HEAD;
4047
4048 enqueue_task(rq, p, queue_flags);
4049 }
4050
4051 check_class_changed(rq, p, prev_class, oldprio);
4052 preempt_disable(); /* avoid rq from going away on us */
4053 task_rq_unlock(rq, p, &flags);
4054
4055 if (pi)
4056 rt_mutex_adjust_pi(p);
4057
4058 /*
4059 * Run balance callbacks after we've adjusted the PI chain.
4060 */
4061 balance_callback(rq);
4062 preempt_enable();
4063
4064 return 0;
4065}
4066
4067static int _sched_setscheduler(struct task_struct *p, int policy,
4068 const struct sched_param *param, bool check)
4069{
4070 struct sched_attr attr = {
4071 .sched_policy = policy,
4072 .sched_priority = param->sched_priority,
4073 .sched_nice = PRIO_TO_NICE(p->static_prio),
4074 };
4075
4076 /* Fixup the legacy SCHED_RESET_ON_FORK hack. */
4077 if ((policy != SETPARAM_POLICY) && (policy & SCHED_RESET_ON_FORK)) {
4078 attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK;
4079 policy &= ~SCHED_RESET_ON_FORK;
4080 attr.sched_policy = policy;
4081 }
4082
4083 return __sched_setscheduler(p, &attr, check, true);
4084}
4085/**
4086 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
4087 * @p: the task in question.
4088 * @policy: new policy.
4089 * @param: structure containing the new RT priority.
4090 *
4091 * Return: 0 on success. An error code otherwise.
4092 *
4093 * NOTE that the task may be already dead.
4094 */
4095int sched_setscheduler(struct task_struct *p, int policy,
4096 const struct sched_param *param)
4097{
4098 return _sched_setscheduler(p, policy, param, true);
4099}
4100EXPORT_SYMBOL_GPL(sched_setscheduler);
4101
4102int sched_setattr(struct task_struct *p, const struct sched_attr *attr)
4103{
4104 return __sched_setscheduler(p, attr, true, true);
4105}
4106EXPORT_SYMBOL_GPL(sched_setattr);
4107
4108/**
4109 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
4110 * @p: the task in question.
4111 * @policy: new policy.
4112 * @param: structure containing the new RT priority.
4113 *
4114 * Just like sched_setscheduler, only don't bother checking if the
4115 * current context has permission. For example, this is needed in
4116 * stop_machine(): we create temporary high priority worker threads,
4117 * but our caller might not have that capability.
4118 *
4119 * Return: 0 on success. An error code otherwise.
4120 */
4121int sched_setscheduler_nocheck(struct task_struct *p, int policy,
4122 const struct sched_param *param)
4123{
4124 return _sched_setscheduler(p, policy, param, false);
4125}
4126EXPORT_SYMBOL_GPL(sched_setscheduler_nocheck);
4127
4128static int
4129do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
4130{
4131 struct sched_param lparam;
4132 struct task_struct *p;
4133 int retval;
4134
4135 if (!param || pid < 0)
4136 return -EINVAL;
4137 if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
4138 return -EFAULT;
4139
4140 rcu_read_lock();
4141 retval = -ESRCH;
4142 p = find_process_by_pid(pid);
4143 if (p != NULL)
4144 retval = sched_setscheduler(p, policy, &lparam);
4145 rcu_read_unlock();
4146
4147 return retval;
4148}
4149
4150/*
4151 * Mimics kernel/events/core.c perf_copy_attr().
4152 */
4153static int sched_copy_attr(struct sched_attr __user *uattr,
4154 struct sched_attr *attr)
4155{
4156 u32 size;
4157 int ret;
4158
4159 if (!access_ok(VERIFY_WRITE, uattr, SCHED_ATTR_SIZE_VER0))
4160 return -EFAULT;
4161
4162 /*
4163 * zero the full structure, so that a short copy will be nice.
4164 */
4165 memset(attr, 0, sizeof(*attr));
4166
4167 ret = get_user(size, &uattr->size);
4168 if (ret)
4169 return ret;
4170
4171 if (size > PAGE_SIZE) /* silly large */
4172 goto err_size;
4173
4174 if (!size) /* abi compat */
4175 size = SCHED_ATTR_SIZE_VER0;
4176
4177 if (size < SCHED_ATTR_SIZE_VER0)
4178 goto err_size;
4179
4180 /*
4181 * If we're handed a bigger struct than we know of,
4182 * ensure all the unknown bits are 0 - i.e. new
4183 * user-space does not rely on any kernel feature
4184 * extensions we dont know about yet.
4185 */
4186 if (size > sizeof(*attr)) {
4187 unsigned char __user *addr;
4188 unsigned char __user *end;
4189 unsigned char val;
4190
4191 addr = (void __user *)uattr + sizeof(*attr);
4192 end = (void __user *)uattr + size;
4193
4194 for (; addr < end; addr++) {
4195 ret = get_user(val, addr);
4196 if (ret)
4197 return ret;
4198 if (val)
4199 goto err_size;
4200 }
4201 size = sizeof(*attr);
4202 }
4203
4204 ret = copy_from_user(attr, uattr, size);
4205 if (ret)
4206 return -EFAULT;
4207
4208 /*
4209 * XXX: do we want to be lenient like existing syscalls; or do we want
4210 * to be strict and return an error on out-of-bounds values?
4211 */
4212 attr->sched_nice = clamp(attr->sched_nice, MIN_NICE, MAX_NICE);
4213
4214 return 0;
4215
4216err_size:
4217 put_user(sizeof(*attr), &uattr->size);
4218 return -E2BIG;
4219}
4220
4221/**
4222 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
4223 * @pid: the pid in question.
4224 * @policy: new policy.
4225 * @param: structure containing the new RT priority.
4226 *
4227 * Return: 0 on success. An error code otherwise.
4228 */
4229SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy,
4230 struct sched_param __user *, param)
4231{
4232 /* negative values for policy are not valid */
4233 if (policy < 0)
4234 return -EINVAL;
4235
4236 return do_sched_setscheduler(pid, policy, param);
4237}
4238
4239/**
4240 * sys_sched_setparam - set/change the RT priority of a thread
4241 * @pid: the pid in question.
4242 * @param: structure containing the new RT priority.
4243 *
4244 * Return: 0 on success. An error code otherwise.
4245 */
4246SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param)
4247{
4248 return do_sched_setscheduler(pid, SETPARAM_POLICY, param);
4249}
4250
4251/**
4252 * sys_sched_setattr - same as above, but with extended sched_attr
4253 * @pid: the pid in question.
4254 * @uattr: structure containing the extended parameters.
4255 * @flags: for future extension.
4256 */
4257SYSCALL_DEFINE3(sched_setattr, pid_t, pid, struct sched_attr __user *, uattr,
4258 unsigned int, flags)
4259{
4260 struct sched_attr attr;
4261 struct task_struct *p;
4262 int retval;
4263
4264 if (!uattr || pid < 0 || flags)
4265 return -EINVAL;
4266
4267 retval = sched_copy_attr(uattr, &attr);
4268 if (retval)
4269 return retval;
4270
4271 if ((int)attr.sched_policy < 0)
4272 return -EINVAL;
4273
4274 rcu_read_lock();
4275 retval = -ESRCH;
4276 p = find_process_by_pid(pid);
4277 if (p != NULL)
4278 retval = sched_setattr(p, &attr);
4279 rcu_read_unlock();
4280
4281 return retval;
4282}
4283
4284/**
4285 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
4286 * @pid: the pid in question.
4287 *
4288 * Return: On success, the policy of the thread. Otherwise, a negative error
4289 * code.
4290 */
4291SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid)
4292{
4293 struct task_struct *p;
4294 int retval;
4295
4296 if (pid < 0)
4297 return -EINVAL;
4298
4299 retval = -ESRCH;
4300 rcu_read_lock();
4301 p = find_process_by_pid(pid);
4302 if (p) {
4303 retval = security_task_getscheduler(p);
4304 if (!retval)
4305 retval = p->policy
4306 | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0);
4307 }
4308 rcu_read_unlock();
4309 return retval;
4310}
4311
4312/**
4313 * sys_sched_getparam - get the RT priority of a thread
4314 * @pid: the pid in question.
4315 * @param: structure containing the RT priority.
4316 *
4317 * Return: On success, 0 and the RT priority is in @param. Otherwise, an error
4318 * code.
4319 */
4320SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param)
4321{
4322 struct sched_param lp = { .sched_priority = 0 };
4323 struct task_struct *p;
4324 int retval;
4325
4326 if (!param || pid < 0)
4327 return -EINVAL;
4328
4329 rcu_read_lock();
4330 p = find_process_by_pid(pid);
4331 retval = -ESRCH;
4332 if (!p)
4333 goto out_unlock;
4334
4335 retval = security_task_getscheduler(p);
4336 if (retval)
4337 goto out_unlock;
4338
4339 if (task_has_rt_policy(p))
4340 lp.sched_priority = p->rt_priority;
4341 rcu_read_unlock();
4342
4343 /*
4344 * This one might sleep, we cannot do it with a spinlock held ...
4345 */
4346 retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;
4347
4348 return retval;
4349
4350out_unlock:
4351 rcu_read_unlock();
4352 return retval;
4353}
4354
4355static int sched_read_attr(struct sched_attr __user *uattr,
4356 struct sched_attr *attr,
4357 unsigned int usize)
4358{
4359 int ret;
4360
4361 if (!access_ok(VERIFY_WRITE, uattr, usize))
4362 return -EFAULT;
4363
4364 /*
4365 * If we're handed a smaller struct than we know of,
4366 * ensure all the unknown bits are 0 - i.e. old
4367 * user-space does not get uncomplete information.
4368 */
4369 if (usize < sizeof(*attr)) {
4370 unsigned char *addr;
4371 unsigned char *end;
4372
4373 addr = (void *)attr + usize;
4374 end = (void *)attr + sizeof(*attr);
4375
4376 for (; addr < end; addr++) {
4377 if (*addr)
4378 return -EFBIG;
4379 }
4380
4381 attr->size = usize;
4382 }
4383
4384 ret = copy_to_user(uattr, attr, attr->size);
4385 if (ret)
4386 return -EFAULT;
4387
4388 return 0;
4389}
4390
4391/**
4392 * sys_sched_getattr - similar to sched_getparam, but with sched_attr
4393 * @pid: the pid in question.
4394 * @uattr: structure containing the extended parameters.
4395 * @size: sizeof(attr) for fwd/bwd comp.
4396 * @flags: for future extension.
4397 */
4398SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr,
4399 unsigned int, size, unsigned int, flags)
4400{
4401 struct sched_attr attr = {
4402 .size = sizeof(struct sched_attr),
4403 };
4404 struct task_struct *p;
4405 int retval;
4406
4407 if (!uattr || pid < 0 || size > PAGE_SIZE ||
4408 size < SCHED_ATTR_SIZE_VER0 || flags)
4409 return -EINVAL;
4410
4411 rcu_read_lock();
4412 p = find_process_by_pid(pid);
4413 retval = -ESRCH;
4414 if (!p)
4415 goto out_unlock;
4416
4417 retval = security_task_getscheduler(p);
4418 if (retval)
4419 goto out_unlock;
4420
4421 attr.sched_policy = p->policy;
4422 if (p->sched_reset_on_fork)
4423 attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK;
4424 if (task_has_dl_policy(p))
4425 __getparam_dl(p, &attr);
4426 else if (task_has_rt_policy(p))
4427 attr.sched_priority = p->rt_priority;
4428 else
4429 attr.sched_nice = task_nice(p);
4430
4431 rcu_read_unlock();
4432
4433 retval = sched_read_attr(uattr, &attr, size);
4434 return retval;
4435
4436out_unlock:
4437 rcu_read_unlock();
4438 return retval;
4439}
4440
4441long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
4442{
4443 cpumask_var_t cpus_allowed, new_mask;
4444 struct task_struct *p;
4445 int retval;
4446
4447 rcu_read_lock();
4448
4449 p = find_process_by_pid(pid);
4450 if (!p) {
4451 rcu_read_unlock();
4452 return -ESRCH;
4453 }
4454
4455 /* Prevent p going away */
4456 get_task_struct(p);
4457 rcu_read_unlock();
4458
4459 if (p->flags & PF_NO_SETAFFINITY) {
4460 retval = -EINVAL;
4461 goto out_put_task;
4462 }
4463 if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) {
4464 retval = -ENOMEM;
4465 goto out_put_task;
4466 }
4467 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
4468 retval = -ENOMEM;
4469 goto out_free_cpus_allowed;
4470 }
4471 retval = -EPERM;
4472 if (!check_same_owner(p)) {
4473 rcu_read_lock();
4474 if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) {
4475 rcu_read_unlock();
4476 goto out_free_new_mask;
4477 }
4478 rcu_read_unlock();
4479 }
4480
4481 retval = security_task_setscheduler(p);
4482 if (retval)
4483 goto out_free_new_mask;
4484
4485
4486 cpuset_cpus_allowed(p, cpus_allowed);
4487 cpumask_and(new_mask, in_mask, cpus_allowed);
4488
4489 /*
4490 * Since bandwidth control happens on root_domain basis,
4491 * if admission test is enabled, we only admit -deadline
4492 * tasks allowed to run on all the CPUs in the task's
4493 * root_domain.
4494 */
4495#ifdef CONFIG_SMP
4496 if (task_has_dl_policy(p) && dl_bandwidth_enabled()) {
4497 rcu_read_lock();
4498 if (!cpumask_subset(task_rq(p)->rd->span, new_mask)) {
4499 retval = -EBUSY;
4500 rcu_read_unlock();
4501 goto out_free_new_mask;
4502 }
4503 rcu_read_unlock();
4504 }
4505#endif
4506again:
4507 retval = __set_cpus_allowed_ptr(p, new_mask, true);
4508
4509 if (!retval) {
4510 cpuset_cpus_allowed(p, cpus_allowed);
4511 if (!cpumask_subset(new_mask, cpus_allowed)) {
4512 /*
4513 * We must have raced with a concurrent cpuset
4514 * update. Just reset the cpus_allowed to the
4515 * cpuset's cpus_allowed
4516 */
4517 cpumask_copy(new_mask, cpus_allowed);
4518 goto again;
4519 }
4520 }
4521out_free_new_mask:
4522 free_cpumask_var(new_mask);
4523out_free_cpus_allowed:
4524 free_cpumask_var(cpus_allowed);
4525out_put_task:
4526 put_task_struct(p);
4527 return retval;
4528}
4529
4530static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
4531 struct cpumask *new_mask)
4532{
4533 if (len < cpumask_size())
4534 cpumask_clear(new_mask);
4535 else if (len > cpumask_size())
4536 len = cpumask_size();
4537
4538 return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
4539}
4540
4541/**
4542 * sys_sched_setaffinity - set the cpu affinity of a process
4543 * @pid: pid of the process
4544 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4545 * @user_mask_ptr: user-space pointer to the new cpu mask
4546 *
4547 * Return: 0 on success. An error code otherwise.
4548 */
4549SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len,
4550 unsigned long __user *, user_mask_ptr)
4551{
4552 cpumask_var_t new_mask;
4553 int retval;
4554
4555 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
4556 return -ENOMEM;
4557
4558 retval = get_user_cpu_mask(user_mask_ptr, len, new_mask);
4559 if (retval == 0)
4560 retval = sched_setaffinity(pid, new_mask);
4561 free_cpumask_var(new_mask);
4562 return retval;
4563}
4564
4565long sched_getaffinity(pid_t pid, struct cpumask *mask)
4566{
4567 struct task_struct *p;
4568 unsigned long flags;
4569 int retval;
4570
4571 rcu_read_lock();
4572
4573 retval = -ESRCH;
4574 p = find_process_by_pid(pid);
4575 if (!p)
4576 goto out_unlock;
4577
4578 retval = security_task_getscheduler(p);
4579 if (retval)
4580 goto out_unlock;
4581
4582 raw_spin_lock_irqsave(&p->pi_lock, flags);
4583 cpumask_and(mask, &p->cpus_allowed, cpu_active_mask);
4584 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
4585
4586out_unlock:
4587 rcu_read_unlock();
4588
4589 return retval;
4590}
4591
4592/**
4593 * sys_sched_getaffinity - get the cpu affinity of a process
4594 * @pid: pid of the process
4595 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4596 * @user_mask_ptr: user-space pointer to hold the current cpu mask
4597 *
4598 * Return: 0 on success. An error code otherwise.
4599 */
4600SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
4601 unsigned long __user *, user_mask_ptr)
4602{
4603 int ret;
4604 cpumask_var_t mask;
4605
4606 if ((len * BITS_PER_BYTE) < nr_cpu_ids)
4607 return -EINVAL;
4608 if (len & (sizeof(unsigned long)-1))
4609 return -EINVAL;
4610
4611 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
4612 return -ENOMEM;
4613
4614 ret = sched_getaffinity(pid, mask);
4615 if (ret == 0) {
4616 size_t retlen = min_t(size_t, len, cpumask_size());
4617
4618 if (copy_to_user(user_mask_ptr, mask, retlen))
4619 ret = -EFAULT;
4620 else
4621 ret = retlen;
4622 }
4623 free_cpumask_var(mask);
4624
4625 return ret;
4626}
4627
4628/**
4629 * sys_sched_yield - yield the current processor to other threads.
4630 *
4631 * This function yields the current CPU to other tasks. If there are no
4632 * other threads running on this CPU then this function will return.
4633 *
4634 * Return: 0.
4635 */
4636SYSCALL_DEFINE0(sched_yield)
4637{
4638 struct rq *rq = this_rq_lock();
4639
4640 schedstat_inc(rq, yld_count);
4641 current->sched_class->yield_task(rq);
4642
4643 /*
4644 * Since we are going to call schedule() anyway, there's
4645 * no need to preempt or enable interrupts:
4646 */
4647 __release(rq->lock);
4648 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
4649 do_raw_spin_unlock(&rq->lock);
4650 sched_preempt_enable_no_resched();
4651
4652 schedule();
4653
4654 return 0;
4655}
4656
4657int __sched _cond_resched(void)
4658{
4659 if (should_resched(0)) {
4660 preempt_schedule_common();
4661 return 1;
4662 }
4663 return 0;
4664}
4665EXPORT_SYMBOL(_cond_resched);
4666
4667/*
4668 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
4669 * call schedule, and on return reacquire the lock.
4670 *
4671 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
4672 * operations here to prevent schedule() from being called twice (once via
4673 * spin_unlock(), once by hand).
4674 */
4675int __cond_resched_lock(spinlock_t *lock)
4676{
4677 int resched = should_resched(PREEMPT_LOCK_OFFSET);
4678 int ret = 0;
4679
4680 lockdep_assert_held(lock);
4681
4682 if (spin_needbreak(lock) || resched) {
4683 spin_unlock(lock);
4684 if (resched)
4685 preempt_schedule_common();
4686 else
4687 cpu_relax();
4688 ret = 1;
4689 spin_lock(lock);
4690 }
4691 return ret;
4692}
4693EXPORT_SYMBOL(__cond_resched_lock);
4694
4695int __sched __cond_resched_softirq(void)
4696{
4697 BUG_ON(!in_softirq());
4698
4699 if (should_resched(SOFTIRQ_DISABLE_OFFSET)) {
4700 local_bh_enable();
4701 preempt_schedule_common();
4702 local_bh_disable();
4703 return 1;
4704 }
4705 return 0;
4706}
4707EXPORT_SYMBOL(__cond_resched_softirq);
4708
4709/**
4710 * yield - yield the current processor to other threads.
4711 *
4712 * Do not ever use this function, there's a 99% chance you're doing it wrong.
4713 *
4714 * The scheduler is at all times free to pick the calling task as the most
4715 * eligible task to run, if removing the yield() call from your code breaks
4716 * it, its already broken.
4717 *
4718 * Typical broken usage is:
4719 *
4720 * while (!event)
4721 * yield();
4722 *
4723 * where one assumes that yield() will let 'the other' process run that will
4724 * make event true. If the current task is a SCHED_FIFO task that will never
4725 * happen. Never use yield() as a progress guarantee!!
4726 *
4727 * If you want to use yield() to wait for something, use wait_event().
4728 * If you want to use yield() to be 'nice' for others, use cond_resched().
4729 * If you still want to use yield(), do not!
4730 */
4731void __sched yield(void)
4732{
4733 set_current_state(TASK_RUNNING);
4734 sys_sched_yield();
4735}
4736EXPORT_SYMBOL(yield);
4737
4738/**
4739 * yield_to - yield the current processor to another thread in
4740 * your thread group, or accelerate that thread toward the
4741 * processor it's on.
4742 * @p: target task
4743 * @preempt: whether task preemption is allowed or not
4744 *
4745 * It's the caller's job to ensure that the target task struct
4746 * can't go away on us before we can do any checks.
4747 *
4748 * Return:
4749 * true (>0) if we indeed boosted the target task.
4750 * false (0) if we failed to boost the target.
4751 * -ESRCH if there's no task to yield to.
4752 */
4753int __sched yield_to(struct task_struct *p, bool preempt)
4754{
4755 struct task_struct *curr = current;
4756 struct rq *rq, *p_rq;
4757 unsigned long flags;
4758 int yielded = 0;
4759
4760 local_irq_save(flags);
4761 rq = this_rq();
4762
4763again:
4764 p_rq = task_rq(p);
4765 /*
4766 * If we're the only runnable task on the rq and target rq also
4767 * has only one task, there's absolutely no point in yielding.
4768 */
4769 if (rq->nr_running == 1 && p_rq->nr_running == 1) {
4770 yielded = -ESRCH;
4771 goto out_irq;
4772 }
4773
4774 double_rq_lock(rq, p_rq);
4775 if (task_rq(p) != p_rq) {
4776 double_rq_unlock(rq, p_rq);
4777 goto again;
4778 }
4779
4780 if (!curr->sched_class->yield_to_task)
4781 goto out_unlock;
4782
4783 if (curr->sched_class != p->sched_class)
4784 goto out_unlock;
4785
4786 if (task_running(p_rq, p) || p->state)
4787 goto out_unlock;
4788
4789 yielded = curr->sched_class->yield_to_task(rq, p, preempt);
4790 if (yielded) {
4791 schedstat_inc(rq, yld_count);
4792 /*
4793 * Make p's CPU reschedule; pick_next_entity takes care of
4794 * fairness.
4795 */
4796 if (preempt && rq != p_rq)
4797 resched_curr(p_rq);
4798 }
4799
4800out_unlock:
4801 double_rq_unlock(rq, p_rq);
4802out_irq:
4803 local_irq_restore(flags);
4804
4805 if (yielded > 0)
4806 schedule();
4807
4808 return yielded;
4809}
4810EXPORT_SYMBOL_GPL(yield_to);
4811
4812/*
4813 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
4814 * that process accounting knows that this is a task in IO wait state.
4815 */
4816long __sched io_schedule_timeout(long timeout)
4817{
4818 int old_iowait = current->in_iowait;
4819 struct rq *rq;
4820 long ret;
4821
4822 current->in_iowait = 1;
4823 blk_schedule_flush_plug(current);
4824
4825 delayacct_blkio_start();
4826 rq = raw_rq();
4827 atomic_inc(&rq->nr_iowait);
4828 ret = schedule_timeout(timeout);
4829 current->in_iowait = old_iowait;
4830 atomic_dec(&rq->nr_iowait);
4831 delayacct_blkio_end();
4832
4833 return ret;
4834}
4835EXPORT_SYMBOL(io_schedule_timeout);
4836
4837/**
4838 * sys_sched_get_priority_max - return maximum RT priority.
4839 * @policy: scheduling class.
4840 *
4841 * Return: On success, this syscall returns the maximum
4842 * rt_priority that can be used by a given scheduling class.
4843 * On failure, a negative error code is returned.
4844 */
4845SYSCALL_DEFINE1(sched_get_priority_max, int, policy)
4846{
4847 int ret = -EINVAL;
4848
4849 switch (policy) {
4850 case SCHED_FIFO:
4851 case SCHED_RR:
4852 ret = MAX_USER_RT_PRIO-1;
4853 break;
4854 case SCHED_DEADLINE:
4855 case SCHED_NORMAL:
4856 case SCHED_BATCH:
4857 case SCHED_IDLE:
4858 ret = 0;
4859 break;
4860 }
4861 return ret;
4862}
4863
4864/**
4865 * sys_sched_get_priority_min - return minimum RT priority.
4866 * @policy: scheduling class.
4867 *
4868 * Return: On success, this syscall returns the minimum
4869 * rt_priority that can be used by a given scheduling class.
4870 * On failure, a negative error code is returned.
4871 */
4872SYSCALL_DEFINE1(sched_get_priority_min, int, policy)
4873{
4874 int ret = -EINVAL;
4875
4876 switch (policy) {
4877 case SCHED_FIFO:
4878 case SCHED_RR:
4879 ret = 1;
4880 break;
4881 case SCHED_DEADLINE:
4882 case SCHED_NORMAL:
4883 case SCHED_BATCH:
4884 case SCHED_IDLE:
4885 ret = 0;
4886 }
4887 return ret;
4888}
4889
4890/**
4891 * sys_sched_rr_get_interval - return the default timeslice of a process.
4892 * @pid: pid of the process.
4893 * @interval: userspace pointer to the timeslice value.
4894 *
4895 * this syscall writes the default timeslice value of a given process
4896 * into the user-space timespec buffer. A value of '0' means infinity.
4897 *
4898 * Return: On success, 0 and the timeslice is in @interval. Otherwise,
4899 * an error code.
4900 */
4901SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid,
4902 struct timespec __user *, interval)
4903{
4904 struct task_struct *p;
4905 unsigned int time_slice;
4906 unsigned long flags;
4907 struct rq *rq;
4908 int retval;
4909 struct timespec t;
4910
4911 if (pid < 0)
4912 return -EINVAL;
4913
4914 retval = -ESRCH;
4915 rcu_read_lock();
4916 p = find_process_by_pid(pid);
4917 if (!p)
4918 goto out_unlock;
4919
4920 retval = security_task_getscheduler(p);
4921 if (retval)
4922 goto out_unlock;
4923
4924 rq = task_rq_lock(p, &flags);
4925 time_slice = 0;
4926 if (p->sched_class->get_rr_interval)
4927 time_slice = p->sched_class->get_rr_interval(rq, p);
4928 task_rq_unlock(rq, p, &flags);
4929
4930 rcu_read_unlock();
4931 jiffies_to_timespec(time_slice, &t);
4932 retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;
4933 return retval;
4934
4935out_unlock:
4936 rcu_read_unlock();
4937 return retval;
4938}
4939
4940static const char stat_nam[] = TASK_STATE_TO_CHAR_STR;
4941
4942void sched_show_task(struct task_struct *p)
4943{
4944 unsigned long free = 0;
4945 int ppid;
4946 unsigned long state = p->state;
4947
4948 if (state)
4949 state = __ffs(state) + 1;
4950 printk(KERN_INFO "%-15.15s %c", p->comm,
4951 state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?');
4952#if BITS_PER_LONG == 32
4953 if (state == TASK_RUNNING)
4954 printk(KERN_CONT " running ");
4955 else
4956 printk(KERN_CONT " %08lx ", thread_saved_pc(p));
4957#else
4958 if (state == TASK_RUNNING)
4959 printk(KERN_CONT " running task ");
4960 else
4961 printk(KERN_CONT " %016lx ", thread_saved_pc(p));
4962#endif
4963#ifdef CONFIG_DEBUG_STACK_USAGE
4964 free = stack_not_used(p);
4965#endif
4966 ppid = 0;
4967 rcu_read_lock();
4968 if (pid_alive(p))
4969 ppid = task_pid_nr(rcu_dereference(p->real_parent));
4970 rcu_read_unlock();
4971 printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free,
4972 task_pid_nr(p), ppid,
4973 (unsigned long)task_thread_info(p)->flags);
4974
4975 print_worker_info(KERN_INFO, p);
4976 show_stack(p, NULL);
4977}
4978
4979void show_state_filter(unsigned long state_filter)
4980{
4981 struct task_struct *g, *p;
4982
4983#if BITS_PER_LONG == 32
4984 printk(KERN_INFO
4985 " task PC stack pid father\n");
4986#else
4987 printk(KERN_INFO
4988 " task PC stack pid father\n");
4989#endif
4990 rcu_read_lock();
4991 for_each_process_thread(g, p) {
4992 /*
4993 * reset the NMI-timeout, listing all files on a slow
4994 * console might take a lot of time:
4995 */
4996 touch_nmi_watchdog();
4997 if (!state_filter || (p->state & state_filter))
4998 sched_show_task(p);
4999 }
5000
5001 touch_all_softlockup_watchdogs();
5002
5003#ifdef CONFIG_SCHED_DEBUG
5004 sysrq_sched_debug_show();
5005#endif
5006 rcu_read_unlock();
5007 /*
5008 * Only show locks if all tasks are dumped:
5009 */
5010 if (!state_filter)
5011 debug_show_all_locks();
5012}
5013
5014void init_idle_bootup_task(struct task_struct *idle)
5015{
5016 idle->sched_class = &idle_sched_class;
5017}
5018
5019/**
5020 * init_idle - set up an idle thread for a given CPU
5021 * @idle: task in question
5022 * @cpu: cpu the idle task belongs to
5023 *
5024 * NOTE: this function does not set the idle thread's NEED_RESCHED
5025 * flag, to make booting more robust.
5026 */
5027void init_idle(struct task_struct *idle, int cpu)
5028{
5029 struct rq *rq = cpu_rq(cpu);
5030 unsigned long flags;
5031
5032 raw_spin_lock_irqsave(&idle->pi_lock, flags);
5033 raw_spin_lock(&rq->lock);
5034
5035 __sched_fork(0, idle);
5036 idle->state = TASK_RUNNING;
5037 idle->se.exec_start = sched_clock();
5038
5039 kasan_unpoison_task_stack(idle);
5040
5041#ifdef CONFIG_SMP
5042 /*
5043 * Its possible that init_idle() gets called multiple times on a task,
5044 * in that case do_set_cpus_allowed() will not do the right thing.
5045 *
5046 * And since this is boot we can forgo the serialization.
5047 */
5048 set_cpus_allowed_common(idle, cpumask_of(cpu));
5049#endif
5050 /*
5051 * We're having a chicken and egg problem, even though we are
5052 * holding rq->lock, the cpu isn't yet set to this cpu so the
5053 * lockdep check in task_group() will fail.
5054 *
5055 * Similar case to sched_fork(). / Alternatively we could
5056 * use task_rq_lock() here and obtain the other rq->lock.
5057 *
5058 * Silence PROVE_RCU
5059 */
5060 rcu_read_lock();
5061 __set_task_cpu(idle, cpu);
5062 rcu_read_unlock();
5063
5064 rq->curr = rq->idle = idle;
5065 idle->on_rq = TASK_ON_RQ_QUEUED;
5066#ifdef CONFIG_SMP
5067 idle->on_cpu = 1;
5068#endif
5069 raw_spin_unlock(&rq->lock);
5070 raw_spin_unlock_irqrestore(&idle->pi_lock, flags);
5071
5072 /* Set the preempt count _outside_ the spinlocks! */
5073 init_idle_preempt_count(idle, cpu);
5074
5075 /*
5076 * The idle tasks have their own, simple scheduling class:
5077 */
5078 idle->sched_class = &idle_sched_class;
5079 ftrace_graph_init_idle_task(idle, cpu);
5080 vtime_init_idle(idle, cpu);
5081#ifdef CONFIG_SMP
5082 sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu);
5083#endif
5084}
5085
5086int cpuset_cpumask_can_shrink(const struct cpumask *cur,
5087 const struct cpumask *trial)
5088{
5089 int ret = 1, trial_cpus;
5090 struct dl_bw *cur_dl_b;
5091 unsigned long flags;
5092
5093 if (!cpumask_weight(cur))
5094 return ret;
5095
5096 rcu_read_lock_sched();
5097 cur_dl_b = dl_bw_of(cpumask_any(cur));
5098 trial_cpus = cpumask_weight(trial);
5099
5100 raw_spin_lock_irqsave(&cur_dl_b->lock, flags);
5101 if (cur_dl_b->bw != -1 &&
5102 cur_dl_b->bw * trial_cpus < cur_dl_b->total_bw)
5103 ret = 0;
5104 raw_spin_unlock_irqrestore(&cur_dl_b->lock, flags);
5105 rcu_read_unlock_sched();
5106
5107 return ret;
5108}
5109
5110int task_can_attach(struct task_struct *p,
5111 const struct cpumask *cs_cpus_allowed)
5112{
5113 int ret = 0;
5114
5115 /*
5116 * Kthreads which disallow setaffinity shouldn't be moved
5117 * to a new cpuset; we don't want to change their cpu
5118 * affinity and isolating such threads by their set of
5119 * allowed nodes is unnecessary. Thus, cpusets are not
5120 * applicable for such threads. This prevents checking for
5121 * success of set_cpus_allowed_ptr() on all attached tasks
5122 * before cpus_allowed may be changed.
5123 */
5124 if (p->flags & PF_NO_SETAFFINITY) {
5125 ret = -EINVAL;
5126 goto out;
5127 }
5128
5129#ifdef CONFIG_SMP
5130 if (dl_task(p) && !cpumask_intersects(task_rq(p)->rd->span,
5131 cs_cpus_allowed)) {
5132 unsigned int dest_cpu = cpumask_any_and(cpu_active_mask,
5133 cs_cpus_allowed);
5134 struct dl_bw *dl_b;
5135 bool overflow;
5136 int cpus;
5137 unsigned long flags;
5138
5139 rcu_read_lock_sched();
5140 dl_b = dl_bw_of(dest_cpu);
5141 raw_spin_lock_irqsave(&dl_b->lock, flags);
5142 cpus = dl_bw_cpus(dest_cpu);
5143 overflow = __dl_overflow(dl_b, cpus, 0, p->dl.dl_bw);
5144 if (overflow)
5145 ret = -EBUSY;
5146 else {
5147 /*
5148 * We reserve space for this task in the destination
5149 * root_domain, as we can't fail after this point.
5150 * We will free resources in the source root_domain
5151 * later on (see set_cpus_allowed_dl()).
5152 */
5153 __dl_add(dl_b, p->dl.dl_bw);
5154 }
5155 raw_spin_unlock_irqrestore(&dl_b->lock, flags);
5156 rcu_read_unlock_sched();
5157
5158 }
5159#endif
5160out:
5161 return ret;
5162}
5163
5164#ifdef CONFIG_SMP
5165
5166#ifdef CONFIG_NUMA_BALANCING
5167/* Migrate current task p to target_cpu */
5168int migrate_task_to(struct task_struct *p, int target_cpu)
5169{
5170 struct migration_arg arg = { p, target_cpu };
5171 int curr_cpu = task_cpu(p);
5172
5173 if (curr_cpu == target_cpu)
5174 return 0;
5175
5176 if (!cpumask_test_cpu(target_cpu, tsk_cpus_allowed(p)))
5177 return -EINVAL;
5178
5179 /* TODO: This is not properly updating schedstats */
5180
5181 trace_sched_move_numa(p, curr_cpu, target_cpu);
5182 return stop_one_cpu(curr_cpu, migration_cpu_stop, &arg);
5183}
5184
5185/*
5186 * Requeue a task on a given node and accurately track the number of NUMA
5187 * tasks on the runqueues
5188 */
5189void sched_setnuma(struct task_struct *p, int nid)
5190{
5191 struct rq *rq;
5192 unsigned long flags;
5193 bool queued, running;
5194
5195 rq = task_rq_lock(p, &flags);
5196 queued = task_on_rq_queued(p);
5197 running = task_current(rq, p);
5198
5199 if (queued)
5200 dequeue_task(rq, p, DEQUEUE_SAVE);
5201 if (running)
5202 put_prev_task(rq, p);
5203
5204 p->numa_preferred_nid = nid;
5205
5206 if (running)
5207 p->sched_class->set_curr_task(rq);
5208 if (queued)
5209 enqueue_task(rq, p, ENQUEUE_RESTORE);
5210 task_rq_unlock(rq, p, &flags);
5211}
5212#endif /* CONFIG_NUMA_BALANCING */
5213
5214#ifdef CONFIG_HOTPLUG_CPU
5215/*
5216 * Ensures that the idle task is using init_mm right before its cpu goes
5217 * offline.
5218 */
5219void idle_task_exit(void)
5220{
5221 struct mm_struct *mm = current->active_mm;
5222
5223 BUG_ON(cpu_online(smp_processor_id()));
5224
5225 if (mm != &init_mm) {
5226 switch_mm(mm, &init_mm, current);
5227 finish_arch_post_lock_switch();
5228 }
5229 mmdrop(mm);
5230}
5231
5232/*
5233 * Since this CPU is going 'away' for a while, fold any nr_active delta
5234 * we might have. Assumes we're called after migrate_tasks() so that the
5235 * nr_active count is stable.
5236 *
5237 * Also see the comment "Global load-average calculations".
5238 */
5239static void calc_load_migrate(struct rq *rq)
5240{
5241 long delta = calc_load_fold_active(rq);
5242 if (delta)
5243 atomic_long_add(delta, &calc_load_tasks);
5244}
5245
5246static void put_prev_task_fake(struct rq *rq, struct task_struct *prev)
5247{
5248}
5249
5250static const struct sched_class fake_sched_class = {
5251 .put_prev_task = put_prev_task_fake,
5252};
5253
5254static struct task_struct fake_task = {
5255 /*
5256 * Avoid pull_{rt,dl}_task()
5257 */
5258 .prio = MAX_PRIO + 1,
5259 .sched_class = &fake_sched_class,
5260};
5261
5262/*
5263 * Migrate all tasks from the rq, sleeping tasks will be migrated by
5264 * try_to_wake_up()->select_task_rq().
5265 *
5266 * Called with rq->lock held even though we'er in stop_machine() and
5267 * there's no concurrency possible, we hold the required locks anyway
5268 * because of lock validation efforts.
5269 */
5270static void migrate_tasks(struct rq *dead_rq)
5271{
5272 struct rq *rq = dead_rq;
5273 struct task_struct *next, *stop = rq->stop;
5274 int dest_cpu;
5275
5276 /*
5277 * Fudge the rq selection such that the below task selection loop
5278 * doesn't get stuck on the currently eligible stop task.
5279 *
5280 * We're currently inside stop_machine() and the rq is either stuck
5281 * in the stop_machine_cpu_stop() loop, or we're executing this code,
5282 * either way we should never end up calling schedule() until we're
5283 * done here.
5284 */
5285 rq->stop = NULL;
5286
5287 /*
5288 * put_prev_task() and pick_next_task() sched
5289 * class method both need to have an up-to-date
5290 * value of rq->clock[_task]
5291 */
5292 update_rq_clock(rq);
5293
5294 for (;;) {
5295 /*
5296 * There's this thread running, bail when that's the only
5297 * remaining thread.
5298 */
5299 if (rq->nr_running == 1)
5300 break;
5301
5302 /*
5303 * pick_next_task assumes pinned rq->lock.
5304 */
5305 lockdep_pin_lock(&rq->lock);
5306 next = pick_next_task(rq, &fake_task);
5307 BUG_ON(!next);
5308 next->sched_class->put_prev_task(rq, next);
5309
5310 /*
5311 * Rules for changing task_struct::cpus_allowed are holding
5312 * both pi_lock and rq->lock, such that holding either
5313 * stabilizes the mask.
5314 *
5315 * Drop rq->lock is not quite as disastrous as it usually is
5316 * because !cpu_active at this point, which means load-balance
5317 * will not interfere. Also, stop-machine.
5318 */
5319 lockdep_unpin_lock(&rq->lock);
5320 raw_spin_unlock(&rq->lock);
5321 raw_spin_lock(&next->pi_lock);
5322 raw_spin_lock(&rq->lock);
5323
5324 /*
5325 * Since we're inside stop-machine, _nothing_ should have
5326 * changed the task, WARN if weird stuff happened, because in
5327 * that case the above rq->lock drop is a fail too.
5328 */
5329 if (WARN_ON(task_rq(next) != rq || !task_on_rq_queued(next))) {
5330 raw_spin_unlock(&next->pi_lock);
5331 continue;
5332 }
5333
5334 /* Find suitable destination for @next, with force if needed. */
5335 dest_cpu = select_fallback_rq(dead_rq->cpu, next);
5336
5337 rq = __migrate_task(rq, next, dest_cpu);
5338 if (rq != dead_rq) {
5339 raw_spin_unlock(&rq->lock);
5340 rq = dead_rq;
5341 raw_spin_lock(&rq->lock);
5342 }
5343 raw_spin_unlock(&next->pi_lock);
5344 }
5345
5346 rq->stop = stop;
5347}
5348#endif /* CONFIG_HOTPLUG_CPU */
5349
5350static void set_rq_online(struct rq *rq)
5351{
5352 if (!rq->online) {
5353 const struct sched_class *class;
5354
5355 cpumask_set_cpu(rq->cpu, rq->rd->online);
5356 rq->online = 1;
5357
5358 for_each_class(class) {
5359 if (class->rq_online)
5360 class->rq_online(rq);
5361 }
5362 }
5363}
5364
5365static void set_rq_offline(struct rq *rq)
5366{
5367 if (rq->online) {
5368 const struct sched_class *class;
5369
5370 for_each_class(class) {
5371 if (class->rq_offline)
5372 class->rq_offline(rq);
5373 }
5374
5375 cpumask_clear_cpu(rq->cpu, rq->rd->online);
5376 rq->online = 0;
5377 }
5378}
5379
5380/*
5381 * migration_call - callback that gets triggered when a CPU is added.
5382 * Here we can start up the necessary migration thread for the new CPU.
5383 */
5384static int
5385migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
5386{
5387 int cpu = (long)hcpu;
5388 unsigned long flags;
5389 struct rq *rq = cpu_rq(cpu);
5390
5391 switch (action & ~CPU_TASKS_FROZEN) {
5392
5393 case CPU_UP_PREPARE:
5394 rq->calc_load_update = calc_load_update;
5395 account_reset_rq(rq);
5396 break;
5397
5398 case CPU_ONLINE:
5399 /* Update our root-domain */
5400 raw_spin_lock_irqsave(&rq->lock, flags);
5401 if (rq->rd) {
5402 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
5403
5404 set_rq_online(rq);
5405 }
5406 raw_spin_unlock_irqrestore(&rq->lock, flags);
5407 break;
5408
5409#ifdef CONFIG_HOTPLUG_CPU
5410 case CPU_DYING:
5411 sched_ttwu_pending();
5412 /* Update our root-domain */
5413 raw_spin_lock_irqsave(&rq->lock, flags);
5414 if (rq->rd) {
5415 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
5416 set_rq_offline(rq);
5417 }
5418 migrate_tasks(rq);
5419 BUG_ON(rq->nr_running != 1); /* the migration thread */
5420 raw_spin_unlock_irqrestore(&rq->lock, flags);
5421 break;
5422
5423 case CPU_DEAD:
5424 calc_load_migrate(rq);
5425 break;
5426#endif
5427 }
5428
5429 update_max_interval();
5430
5431 return NOTIFY_OK;
5432}
5433
5434/*
5435 * Register at high priority so that task migration (migrate_all_tasks)
5436 * happens before everything else. This has to be lower priority than
5437 * the notifier in the perf_event subsystem, though.
5438 */
5439static struct notifier_block migration_notifier = {
5440 .notifier_call = migration_call,
5441 .priority = CPU_PRI_MIGRATION,
5442};
5443
5444static void set_cpu_rq_start_time(void)
5445{
5446 int cpu = smp_processor_id();
5447 struct rq *rq = cpu_rq(cpu);
5448 rq->age_stamp = sched_clock_cpu(cpu);
5449}
5450
5451static int sched_cpu_active(struct notifier_block *nfb,
5452 unsigned long action, void *hcpu)
5453{
5454 int cpu = (long)hcpu;
5455
5456 switch (action & ~CPU_TASKS_FROZEN) {
5457 case CPU_STARTING:
5458 set_cpu_rq_start_time();
5459 return NOTIFY_OK;
5460
5461 case CPU_DOWN_FAILED:
5462 set_cpu_active(cpu, true);
5463 return NOTIFY_OK;
5464
5465 default:
5466 return NOTIFY_DONE;
5467 }
5468}
5469
5470static int sched_cpu_inactive(struct notifier_block *nfb,
5471 unsigned long action, void *hcpu)
5472{
5473 switch (action & ~CPU_TASKS_FROZEN) {
5474 case CPU_DOWN_PREPARE:
5475 set_cpu_active((long)hcpu, false);
5476 return NOTIFY_OK;
5477 default:
5478 return NOTIFY_DONE;
5479 }
5480}
5481
5482static int __init migration_init(void)
5483{
5484 void *cpu = (void *)(long)smp_processor_id();
5485 int err;
5486
5487 /* Initialize migration for the boot CPU */
5488 err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
5489 BUG_ON(err == NOTIFY_BAD);
5490 migration_call(&migration_notifier, CPU_ONLINE, cpu);
5491 register_cpu_notifier(&migration_notifier);
5492
5493 /* Register cpu active notifiers */
5494 cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE);
5495 cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE);
5496
5497 return 0;
5498}
5499early_initcall(migration_init);
5500
5501static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */
5502
5503#ifdef CONFIG_SCHED_DEBUG
5504
5505static __read_mostly int sched_debug_enabled;
5506
5507static int __init sched_debug_setup(char *str)
5508{
5509 sched_debug_enabled = 1;
5510
5511 return 0;
5512}
5513early_param("sched_debug", sched_debug_setup);
5514
5515static inline bool sched_debug(void)
5516{
5517 return sched_debug_enabled;
5518}
5519
5520static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
5521 struct cpumask *groupmask)
5522{
5523 struct sched_group *group = sd->groups;
5524
5525 cpumask_clear(groupmask);
5526
5527 printk(KERN_DEBUG "%*s domain %d: ", level, "", level);
5528
5529 if (!(sd->flags & SD_LOAD_BALANCE)) {
5530 printk("does not load-balance\n");
5531 if (sd->parent)
5532 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain"
5533 " has parent");
5534 return -1;
5535 }
5536
5537 printk(KERN_CONT "span %*pbl level %s\n",
5538 cpumask_pr_args(sched_domain_span(sd)), sd->name);
5539
5540 if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) {
5541 printk(KERN_ERR "ERROR: domain->span does not contain "
5542 "CPU%d\n", cpu);
5543 }
5544 if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) {
5545 printk(KERN_ERR "ERROR: domain->groups does not contain"
5546 " CPU%d\n", cpu);
5547 }
5548
5549 printk(KERN_DEBUG "%*s groups:", level + 1, "");
5550 do {
5551 if (!group) {
5552 printk("\n");
5553 printk(KERN_ERR "ERROR: group is NULL\n");
5554 break;
5555 }
5556
5557 if (!cpumask_weight(sched_group_cpus(group))) {
5558 printk(KERN_CONT "\n");
5559 printk(KERN_ERR "ERROR: empty group\n");
5560 break;
5561 }
5562
5563 if (!(sd->flags & SD_OVERLAP) &&
5564 cpumask_intersects(groupmask, sched_group_cpus(group))) {
5565 printk(KERN_CONT "\n");
5566 printk(KERN_ERR "ERROR: repeated CPUs\n");
5567 break;
5568 }
5569
5570 cpumask_or(groupmask, groupmask, sched_group_cpus(group));
5571
5572 printk(KERN_CONT " %*pbl",
5573 cpumask_pr_args(sched_group_cpus(group)));
5574 if (group->sgc->capacity != SCHED_CAPACITY_SCALE) {
5575 printk(KERN_CONT " (cpu_capacity = %d)",
5576 group->sgc->capacity);
5577 }
5578
5579 group = group->next;
5580 } while (group != sd->groups);
5581 printk(KERN_CONT "\n");
5582
5583 if (!cpumask_equal(sched_domain_span(sd), groupmask))
5584 printk(KERN_ERR "ERROR: groups don't span domain->span\n");
5585
5586 if (sd->parent &&
5587 !cpumask_subset(groupmask, sched_domain_span(sd->parent)))
5588 printk(KERN_ERR "ERROR: parent span is not a superset "
5589 "of domain->span\n");
5590 return 0;
5591}
5592
5593static void sched_domain_debug(struct sched_domain *sd, int cpu)
5594{
5595 int level = 0;
5596
5597 if (!sched_debug_enabled)
5598 return;
5599
5600 if (!sd) {
5601 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
5602 return;
5603 }
5604
5605 printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu);
5606
5607 for (;;) {
5608 if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask))
5609 break;
5610 level++;
5611 sd = sd->parent;
5612 if (!sd)
5613 break;
5614 }
5615}
5616#else /* !CONFIG_SCHED_DEBUG */
5617# define sched_domain_debug(sd, cpu) do { } while (0)
5618static inline bool sched_debug(void)
5619{
5620 return false;
5621}
5622#endif /* CONFIG_SCHED_DEBUG */
5623
5624static int sd_degenerate(struct sched_domain *sd)
5625{
5626 if (cpumask_weight(sched_domain_span(sd)) == 1)
5627 return 1;
5628
5629 /* Following flags need at least 2 groups */
5630 if (sd->flags & (SD_LOAD_BALANCE |
5631 SD_BALANCE_NEWIDLE |
5632 SD_BALANCE_FORK |
5633 SD_BALANCE_EXEC |
5634 SD_SHARE_CPUCAPACITY |
5635 SD_SHARE_PKG_RESOURCES |
5636 SD_SHARE_POWERDOMAIN)) {
5637 if (sd->groups != sd->groups->next)
5638 return 0;
5639 }
5640
5641 /* Following flags don't use groups */
5642 if (sd->flags & (SD_WAKE_AFFINE))
5643 return 0;
5644
5645 return 1;
5646}
5647
5648static int
5649sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
5650{
5651 unsigned long cflags = sd->flags, pflags = parent->flags;
5652
5653 if (sd_degenerate(parent))
5654 return 1;
5655
5656 if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent)))
5657 return 0;
5658
5659 /* Flags needing groups don't count if only 1 group in parent */
5660 if (parent->groups == parent->groups->next) {
5661 pflags &= ~(SD_LOAD_BALANCE |
5662 SD_BALANCE_NEWIDLE |
5663 SD_BALANCE_FORK |
5664 SD_BALANCE_EXEC |
5665 SD_SHARE_CPUCAPACITY |
5666 SD_SHARE_PKG_RESOURCES |
5667 SD_PREFER_SIBLING |
5668 SD_SHARE_POWERDOMAIN);
5669 if (nr_node_ids == 1)
5670 pflags &= ~SD_SERIALIZE;
5671 }
5672 if (~cflags & pflags)
5673 return 0;
5674
5675 return 1;
5676}
5677
5678static void free_rootdomain(struct rcu_head *rcu)
5679{
5680 struct root_domain *rd = container_of(rcu, struct root_domain, rcu);
5681
5682 cpupri_cleanup(&rd->cpupri);
5683 cpudl_cleanup(&rd->cpudl);
5684 free_cpumask_var(rd->dlo_mask);
5685 free_cpumask_var(rd->rto_mask);
5686 free_cpumask_var(rd->online);
5687 free_cpumask_var(rd->span);
5688 kfree(rd);
5689}
5690
5691static void rq_attach_root(struct rq *rq, struct root_domain *rd)
5692{
5693 struct root_domain *old_rd = NULL;
5694 unsigned long flags;
5695
5696 raw_spin_lock_irqsave(&rq->lock, flags);
5697
5698 if (rq->rd) {
5699 old_rd = rq->rd;
5700
5701 if (cpumask_test_cpu(rq->cpu, old_rd->online))
5702 set_rq_offline(rq);
5703
5704 cpumask_clear_cpu(rq->cpu, old_rd->span);
5705
5706 /*
5707 * If we dont want to free the old_rd yet then
5708 * set old_rd to NULL to skip the freeing later
5709 * in this function:
5710 */
5711 if (!atomic_dec_and_test(&old_rd->refcount))
5712 old_rd = NULL;
5713 }
5714
5715 atomic_inc(&rd->refcount);
5716 rq->rd = rd;
5717
5718 cpumask_set_cpu(rq->cpu, rd->span);
5719 if (cpumask_test_cpu(rq->cpu, cpu_active_mask))
5720 set_rq_online(rq);
5721
5722 raw_spin_unlock_irqrestore(&rq->lock, flags);
5723
5724 if (old_rd)
5725 call_rcu_sched(&old_rd->rcu, free_rootdomain);
5726}
5727
5728static int init_rootdomain(struct root_domain *rd)
5729{
5730 memset(rd, 0, sizeof(*rd));
5731
5732 if (!zalloc_cpumask_var(&rd->span, GFP_KERNEL))
5733 goto out;
5734 if (!zalloc_cpumask_var(&rd->online, GFP_KERNEL))
5735 goto free_span;
5736 if (!zalloc_cpumask_var(&rd->dlo_mask, GFP_KERNEL))
5737 goto free_online;
5738 if (!zalloc_cpumask_var(&rd->rto_mask, GFP_KERNEL))
5739 goto free_dlo_mask;
5740
5741 init_dl_bw(&rd->dl_bw);
5742 if (cpudl_init(&rd->cpudl) != 0)
5743 goto free_dlo_mask;
5744
5745 if (cpupri_init(&rd->cpupri) != 0)
5746 goto free_rto_mask;
5747 return 0;
5748
5749free_rto_mask:
5750 free_cpumask_var(rd->rto_mask);
5751free_dlo_mask:
5752 free_cpumask_var(rd->dlo_mask);
5753free_online:
5754 free_cpumask_var(rd->online);
5755free_span:
5756 free_cpumask_var(rd->span);
5757out:
5758 return -ENOMEM;
5759}
5760
5761/*
5762 * By default the system creates a single root-domain with all cpus as
5763 * members (mimicking the global state we have today).
5764 */
5765struct root_domain def_root_domain;
5766
5767static void init_defrootdomain(void)
5768{
5769 init_rootdomain(&def_root_domain);
5770
5771 atomic_set(&def_root_domain.refcount, 1);
5772}
5773
5774static struct root_domain *alloc_rootdomain(void)
5775{
5776 struct root_domain *rd;
5777
5778 rd = kmalloc(sizeof(*rd), GFP_KERNEL);
5779 if (!rd)
5780 return NULL;
5781
5782 if (init_rootdomain(rd) != 0) {
5783 kfree(rd);
5784 return NULL;
5785 }
5786
5787 return rd;
5788}
5789
5790static void free_sched_groups(struct sched_group *sg, int free_sgc)
5791{
5792 struct sched_group *tmp, *first;
5793
5794 if (!sg)
5795 return;
5796
5797 first = sg;
5798 do {
5799 tmp = sg->next;
5800
5801 if (free_sgc && atomic_dec_and_test(&sg->sgc->ref))
5802 kfree(sg->sgc);
5803
5804 kfree(sg);
5805 sg = tmp;
5806 } while (sg != first);
5807}
5808
5809static void free_sched_domain(struct rcu_head *rcu)
5810{
5811 struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu);
5812
5813 /*
5814 * If its an overlapping domain it has private groups, iterate and
5815 * nuke them all.
5816 */
5817 if (sd->flags & SD_OVERLAP) {
5818 free_sched_groups(sd->groups, 1);
5819 } else if (atomic_dec_and_test(&sd->groups->ref)) {
5820 kfree(sd->groups->sgc);
5821 kfree(sd->groups);
5822 }
5823 kfree(sd);
5824}
5825
5826static void destroy_sched_domain(struct sched_domain *sd, int cpu)
5827{
5828 call_rcu(&sd->rcu, free_sched_domain);
5829}
5830
5831static void destroy_sched_domains(struct sched_domain *sd, int cpu)
5832{
5833 for (; sd; sd = sd->parent)
5834 destroy_sched_domain(sd, cpu);
5835}
5836
5837/*
5838 * Keep a special pointer to the highest sched_domain that has
5839 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this
5840 * allows us to avoid some pointer chasing select_idle_sibling().
5841 *
5842 * Also keep a unique ID per domain (we use the first cpu number in
5843 * the cpumask of the domain), this allows us to quickly tell if
5844 * two cpus are in the same cache domain, see cpus_share_cache().
5845 */
5846DEFINE_PER_CPU(struct sched_domain *, sd_llc);
5847DEFINE_PER_CPU(int, sd_llc_size);
5848DEFINE_PER_CPU(int, sd_llc_id);
5849DEFINE_PER_CPU(struct sched_domain *, sd_numa);
5850DEFINE_PER_CPU(struct sched_domain *, sd_busy);
5851DEFINE_PER_CPU(struct sched_domain *, sd_asym);
5852
5853static void update_top_cache_domain(int cpu)
5854{
5855 struct sched_domain *sd;
5856 struct sched_domain *busy_sd = NULL;
5857 int id = cpu;
5858 int size = 1;
5859
5860 sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES);
5861 if (sd) {
5862 id = cpumask_first(sched_domain_span(sd));
5863 size = cpumask_weight(sched_domain_span(sd));
5864 busy_sd = sd->parent; /* sd_busy */
5865 }
5866 rcu_assign_pointer(per_cpu(sd_busy, cpu), busy_sd);
5867
5868 rcu_assign_pointer(per_cpu(sd_llc, cpu), sd);
5869 per_cpu(sd_llc_size, cpu) = size;
5870 per_cpu(sd_llc_id, cpu) = id;
5871
5872 sd = lowest_flag_domain(cpu, SD_NUMA);
5873 rcu_assign_pointer(per_cpu(sd_numa, cpu), sd);
5874
5875 sd = highest_flag_domain(cpu, SD_ASYM_PACKING);
5876 rcu_assign_pointer(per_cpu(sd_asym, cpu), sd);
5877}
5878
5879/*
5880 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
5881 * hold the hotplug lock.
5882 */
5883static void
5884cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
5885{
5886 struct rq *rq = cpu_rq(cpu);
5887 struct sched_domain *tmp;
5888
5889 /* Remove the sched domains which do not contribute to scheduling. */
5890 for (tmp = sd; tmp; ) {
5891 struct sched_domain *parent = tmp->parent;
5892 if (!parent)
5893 break;
5894
5895 if (sd_parent_degenerate(tmp, parent)) {
5896 tmp->parent = parent->parent;
5897 if (parent->parent)
5898 parent->parent->child = tmp;
5899 /*
5900 * Transfer SD_PREFER_SIBLING down in case of a
5901 * degenerate parent; the spans match for this
5902 * so the property transfers.
5903 */
5904 if (parent->flags & SD_PREFER_SIBLING)
5905 tmp->flags |= SD_PREFER_SIBLING;
5906 destroy_sched_domain(parent, cpu);
5907 } else
5908 tmp = tmp->parent;
5909 }
5910
5911 if (sd && sd_degenerate(sd)) {
5912 tmp = sd;
5913 sd = sd->parent;
5914 destroy_sched_domain(tmp, cpu);
5915 if (sd)
5916 sd->child = NULL;
5917 }
5918
5919 sched_domain_debug(sd, cpu);
5920
5921 rq_attach_root(rq, rd);
5922 tmp = rq->sd;
5923 rcu_assign_pointer(rq->sd, sd);
5924 destroy_sched_domains(tmp, cpu);
5925
5926 update_top_cache_domain(cpu);
5927}
5928
5929/* Setup the mask of cpus configured for isolated domains */
5930static int __init isolated_cpu_setup(char *str)
5931{
5932 int ret;
5933
5934 alloc_bootmem_cpumask_var(&cpu_isolated_map);
5935 ret = cpulist_parse(str, cpu_isolated_map);
5936 if (ret) {
5937 pr_err("sched: Error, all isolcpus= values must be between 0 and %d\n", nr_cpu_ids);
5938 return 0;
5939 }
5940 return 1;
5941}
5942__setup("isolcpus=", isolated_cpu_setup);
5943
5944struct s_data {
5945 struct sched_domain ** __percpu sd;
5946 struct root_domain *rd;
5947};
5948
5949enum s_alloc {
5950 sa_rootdomain,
5951 sa_sd,
5952 sa_sd_storage,
5953 sa_none,
5954};
5955
5956/*
5957 * Build an iteration mask that can exclude certain CPUs from the upwards
5958 * domain traversal.
5959 *
5960 * Asymmetric node setups can result in situations where the domain tree is of
5961 * unequal depth, make sure to skip domains that already cover the entire
5962 * range.
5963 *
5964 * In that case build_sched_domains() will have terminated the iteration early
5965 * and our sibling sd spans will be empty. Domains should always include the
5966 * cpu they're built on, so check that.
5967 *
5968 */
5969static void build_group_mask(struct sched_domain *sd, struct sched_group *sg)
5970{
5971 const struct cpumask *span = sched_domain_span(sd);
5972 struct sd_data *sdd = sd->private;
5973 struct sched_domain *sibling;
5974 int i;
5975
5976 for_each_cpu(i, span) {
5977 sibling = *per_cpu_ptr(sdd->sd, i);
5978 if (!cpumask_test_cpu(i, sched_domain_span(sibling)))
5979 continue;
5980
5981 cpumask_set_cpu(i, sched_group_mask(sg));
5982 }
5983}
5984
5985/*
5986 * Return the canonical balance cpu for this group, this is the first cpu
5987 * of this group that's also in the iteration mask.
5988 */
5989int group_balance_cpu(struct sched_group *sg)
5990{
5991 return cpumask_first_and(sched_group_cpus(sg), sched_group_mask(sg));
5992}
5993
5994static int
5995build_overlap_sched_groups(struct sched_domain *sd, int cpu)
5996{
5997 struct sched_group *first = NULL, *last = NULL, *groups = NULL, *sg;
5998 const struct cpumask *span = sched_domain_span(sd);
5999 struct cpumask *covered = sched_domains_tmpmask;
6000 struct sd_data *sdd = sd->private;
6001 struct sched_domain *sibling;
6002 int i;
6003
6004 cpumask_clear(covered);
6005
6006 for_each_cpu(i, span) {
6007 struct cpumask *sg_span;
6008
6009 if (cpumask_test_cpu(i, covered))
6010 continue;
6011
6012 sibling = *per_cpu_ptr(sdd->sd, i);
6013
6014 /* See the comment near build_group_mask(). */
6015 if (!cpumask_test_cpu(i, sched_domain_span(sibling)))
6016 continue;
6017
6018 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
6019 GFP_KERNEL, cpu_to_node(cpu));
6020
6021 if (!sg)
6022 goto fail;
6023
6024 sg_span = sched_group_cpus(sg);
6025 if (sibling->child)
6026 cpumask_copy(sg_span, sched_domain_span(sibling->child));
6027 else
6028 cpumask_set_cpu(i, sg_span);
6029
6030 cpumask_or(covered, covered, sg_span);
6031
6032 sg->sgc = *per_cpu_ptr(sdd->sgc, i);
6033 if (atomic_inc_return(&sg->sgc->ref) == 1)
6034 build_group_mask(sd, sg);
6035
6036 /*
6037 * Initialize sgc->capacity such that even if we mess up the
6038 * domains and no possible iteration will get us here, we won't
6039 * die on a /0 trap.
6040 */
6041 sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sg_span);
6042
6043 /*
6044 * Make sure the first group of this domain contains the
6045 * canonical balance cpu. Otherwise the sched_domain iteration
6046 * breaks. See update_sg_lb_stats().
6047 */
6048 if ((!groups && cpumask_test_cpu(cpu, sg_span)) ||
6049 group_balance_cpu(sg) == cpu)
6050 groups = sg;
6051
6052 if (!first)
6053 first = sg;
6054 if (last)
6055 last->next = sg;
6056 last = sg;
6057 last->next = first;
6058 }
6059 sd->groups = groups;
6060
6061 return 0;
6062
6063fail:
6064 free_sched_groups(first, 0);
6065
6066 return -ENOMEM;
6067}
6068
6069static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg)
6070{
6071 struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu);
6072 struct sched_domain *child = sd->child;
6073
6074 if (child)
6075 cpu = cpumask_first(sched_domain_span(child));
6076
6077 if (sg) {
6078 *sg = *per_cpu_ptr(sdd->sg, cpu);
6079 (*sg)->sgc = *per_cpu_ptr(sdd->sgc, cpu);
6080 atomic_set(&(*sg)->sgc->ref, 1); /* for claim_allocations */
6081 }
6082
6083 return cpu;
6084}
6085
6086/*
6087 * build_sched_groups will build a circular linked list of the groups
6088 * covered by the given span, and will set each group's ->cpumask correctly,
6089 * and ->cpu_capacity to 0.
6090 *
6091 * Assumes the sched_domain tree is fully constructed
6092 */
6093static int
6094build_sched_groups(struct sched_domain *sd, int cpu)
6095{
6096 struct sched_group *first = NULL, *last = NULL;
6097 struct sd_data *sdd = sd->private;
6098 const struct cpumask *span = sched_domain_span(sd);
6099 struct cpumask *covered;
6100 int i;
6101
6102 get_group(cpu, sdd, &sd->groups);
6103 atomic_inc(&sd->groups->ref);
6104
6105 if (cpu != cpumask_first(span))
6106 return 0;
6107
6108 lockdep_assert_held(&sched_domains_mutex);
6109 covered = sched_domains_tmpmask;
6110
6111 cpumask_clear(covered);
6112
6113 for_each_cpu(i, span) {
6114 struct sched_group *sg;
6115 int group, j;
6116
6117 if (cpumask_test_cpu(i, covered))
6118 continue;
6119
6120 group = get_group(i, sdd, &sg);
6121 cpumask_setall(sched_group_mask(sg));
6122
6123 for_each_cpu(j, span) {
6124 if (get_group(j, sdd, NULL) != group)
6125 continue;
6126
6127 cpumask_set_cpu(j, covered);
6128 cpumask_set_cpu(j, sched_group_cpus(sg));
6129 }
6130
6131 if (!first)
6132 first = sg;
6133 if (last)
6134 last->next = sg;
6135 last = sg;
6136 }
6137 last->next = first;
6138
6139 return 0;
6140}
6141
6142/*
6143 * Initialize sched groups cpu_capacity.
6144 *
6145 * cpu_capacity indicates the capacity of sched group, which is used while
6146 * distributing the load between different sched groups in a sched domain.
6147 * Typically cpu_capacity for all the groups in a sched domain will be same
6148 * unless there are asymmetries in the topology. If there are asymmetries,
6149 * group having more cpu_capacity will pickup more load compared to the
6150 * group having less cpu_capacity.
6151 */
6152static void init_sched_groups_capacity(int cpu, struct sched_domain *sd)
6153{
6154 struct sched_group *sg = sd->groups;
6155
6156 WARN_ON(!sg);
6157
6158 do {
6159 sg->group_weight = cpumask_weight(sched_group_cpus(sg));
6160 sg = sg->next;
6161 } while (sg != sd->groups);
6162
6163 if (cpu != group_balance_cpu(sg))
6164 return;
6165
6166 update_group_capacity(sd, cpu);
6167 atomic_set(&sg->sgc->nr_busy_cpus, sg->group_weight);
6168}
6169
6170/*
6171 * Initializers for schedule domains
6172 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
6173 */
6174
6175static int default_relax_domain_level = -1;
6176int sched_domain_level_max;
6177
6178static int __init setup_relax_domain_level(char *str)
6179{
6180 if (kstrtoint(str, 0, &default_relax_domain_level))
6181 pr_warn("Unable to set relax_domain_level\n");
6182
6183 return 1;
6184}
6185__setup("relax_domain_level=", setup_relax_domain_level);
6186
6187static void set_domain_attribute(struct sched_domain *sd,
6188 struct sched_domain_attr *attr)
6189{
6190 int request;
6191
6192 if (!attr || attr->relax_domain_level < 0) {
6193 if (default_relax_domain_level < 0)
6194 return;
6195 else
6196 request = default_relax_domain_level;
6197 } else
6198 request = attr->relax_domain_level;
6199 if (request < sd->level) {
6200 /* turn off idle balance on this domain */
6201 sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
6202 } else {
6203 /* turn on idle balance on this domain */
6204 sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
6205 }
6206}
6207
6208static void __sdt_free(const struct cpumask *cpu_map);
6209static int __sdt_alloc(const struct cpumask *cpu_map);
6210
6211static void __free_domain_allocs(struct s_data *d, enum s_alloc what,
6212 const struct cpumask *cpu_map)
6213{
6214 switch (what) {
6215 case sa_rootdomain:
6216 if (!atomic_read(&d->rd->refcount))
6217 free_rootdomain(&d->rd->rcu); /* fall through */
6218 case sa_sd:
6219 free_percpu(d->sd); /* fall through */
6220 case sa_sd_storage:
6221 __sdt_free(cpu_map); /* fall through */
6222 case sa_none:
6223 break;
6224 }
6225}
6226
6227static enum s_alloc __visit_domain_allocation_hell(struct s_data *d,
6228 const struct cpumask *cpu_map)
6229{
6230 memset(d, 0, sizeof(*d));
6231
6232 if (__sdt_alloc(cpu_map))
6233 return sa_sd_storage;
6234 d->sd = alloc_percpu(struct sched_domain *);
6235 if (!d->sd)
6236 return sa_sd_storage;
6237 d->rd = alloc_rootdomain();
6238 if (!d->rd)
6239 return sa_sd;
6240 return sa_rootdomain;
6241}
6242
6243/*
6244 * NULL the sd_data elements we've used to build the sched_domain and
6245 * sched_group structure so that the subsequent __free_domain_allocs()
6246 * will not free the data we're using.
6247 */
6248static void claim_allocations(int cpu, struct sched_domain *sd)
6249{
6250 struct sd_data *sdd = sd->private;
6251
6252 WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd);
6253 *per_cpu_ptr(sdd->sd, cpu) = NULL;
6254
6255 if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref))
6256 *per_cpu_ptr(sdd->sg, cpu) = NULL;
6257
6258 if (atomic_read(&(*per_cpu_ptr(sdd->sgc, cpu))->ref))
6259 *per_cpu_ptr(sdd->sgc, cpu) = NULL;
6260}
6261
6262#ifdef CONFIG_NUMA
6263static int sched_domains_numa_levels;
6264enum numa_topology_type sched_numa_topology_type;
6265static int *sched_domains_numa_distance;
6266int sched_max_numa_distance;
6267static struct cpumask ***sched_domains_numa_masks;
6268static int sched_domains_curr_level;
6269#endif
6270
6271/*
6272 * SD_flags allowed in topology descriptions.
6273 *
6274 * SD_SHARE_CPUCAPACITY - describes SMT topologies
6275 * SD_SHARE_PKG_RESOURCES - describes shared caches
6276 * SD_NUMA - describes NUMA topologies
6277 * SD_SHARE_POWERDOMAIN - describes shared power domain
6278 *
6279 * Odd one out:
6280 * SD_ASYM_PACKING - describes SMT quirks
6281 */
6282#define TOPOLOGY_SD_FLAGS \
6283 (SD_SHARE_CPUCAPACITY | \
6284 SD_SHARE_PKG_RESOURCES | \
6285 SD_NUMA | \
6286 SD_ASYM_PACKING | \
6287 SD_SHARE_POWERDOMAIN)
6288
6289static struct sched_domain *
6290sd_init(struct sched_domain_topology_level *tl, int cpu)
6291{
6292 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu);
6293 int sd_weight, sd_flags = 0;
6294
6295#ifdef CONFIG_NUMA
6296 /*
6297 * Ugly hack to pass state to sd_numa_mask()...
6298 */
6299 sched_domains_curr_level = tl->numa_level;
6300#endif
6301
6302 sd_weight = cpumask_weight(tl->mask(cpu));
6303
6304 if (tl->sd_flags)
6305 sd_flags = (*tl->sd_flags)();
6306 if (WARN_ONCE(sd_flags & ~TOPOLOGY_SD_FLAGS,
6307 "wrong sd_flags in topology description\n"))
6308 sd_flags &= ~TOPOLOGY_SD_FLAGS;
6309
6310 *sd = (struct sched_domain){
6311 .min_interval = sd_weight,
6312 .max_interval = 2*sd_weight,
6313 .busy_factor = 32,
6314 .imbalance_pct = 125,
6315
6316 .cache_nice_tries = 0,
6317 .busy_idx = 0,
6318 .idle_idx = 0,
6319 .newidle_idx = 0,
6320 .wake_idx = 0,
6321 .forkexec_idx = 0,
6322
6323 .flags = 1*SD_LOAD_BALANCE
6324 | 1*SD_BALANCE_NEWIDLE
6325 | 1*SD_BALANCE_EXEC
6326 | 1*SD_BALANCE_FORK
6327 | 0*SD_BALANCE_WAKE
6328 | 1*SD_WAKE_AFFINE
6329 | 0*SD_SHARE_CPUCAPACITY
6330 | 0*SD_SHARE_PKG_RESOURCES
6331 | 0*SD_SERIALIZE
6332 | 0*SD_PREFER_SIBLING
6333 | 0*SD_NUMA
6334 | sd_flags
6335 ,
6336
6337 .last_balance = jiffies,
6338 .balance_interval = sd_weight,
6339 .smt_gain = 0,
6340 .max_newidle_lb_cost = 0,
6341 .next_decay_max_lb_cost = jiffies,
6342#ifdef CONFIG_SCHED_DEBUG
6343 .name = tl->name,
6344#endif
6345 };
6346
6347 /*
6348 * Convert topological properties into behaviour.
6349 */
6350
6351 if (sd->flags & SD_SHARE_CPUCAPACITY) {
6352 sd->flags |= SD_PREFER_SIBLING;
6353 sd->imbalance_pct = 110;
6354 sd->smt_gain = 1178; /* ~15% */
6355
6356 } else if (sd->flags & SD_SHARE_PKG_RESOURCES) {
6357 sd->imbalance_pct = 117;
6358 sd->cache_nice_tries = 1;
6359 sd->busy_idx = 2;
6360
6361#ifdef CONFIG_NUMA
6362 } else if (sd->flags & SD_NUMA) {
6363 sd->cache_nice_tries = 2;
6364 sd->busy_idx = 3;
6365 sd->idle_idx = 2;
6366
6367 sd->flags |= SD_SERIALIZE;
6368 if (sched_domains_numa_distance[tl->numa_level] > RECLAIM_DISTANCE) {
6369 sd->flags &= ~(SD_BALANCE_EXEC |
6370 SD_BALANCE_FORK |
6371 SD_WAKE_AFFINE);
6372 }
6373
6374#endif
6375 } else {
6376 sd->flags |= SD_PREFER_SIBLING;
6377 sd->cache_nice_tries = 1;
6378 sd->busy_idx = 2;
6379 sd->idle_idx = 1;
6380 }
6381
6382 sd->private = &tl->data;
6383
6384 return sd;
6385}
6386
6387/*
6388 * Topology list, bottom-up.
6389 */
6390static struct sched_domain_topology_level default_topology[] = {
6391#ifdef CONFIG_SCHED_SMT
6392 { cpu_smt_mask, cpu_smt_flags, SD_INIT_NAME(SMT) },
6393#endif
6394#ifdef CONFIG_SCHED_MC
6395 { cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) },
6396#endif
6397 { cpu_cpu_mask, SD_INIT_NAME(DIE) },
6398 { NULL, },
6399};
6400
6401static struct sched_domain_topology_level *sched_domain_topology =
6402 default_topology;
6403
6404#define for_each_sd_topology(tl) \
6405 for (tl = sched_domain_topology; tl->mask; tl++)
6406
6407void set_sched_topology(struct sched_domain_topology_level *tl)
6408{
6409 sched_domain_topology = tl;
6410}
6411
6412#ifdef CONFIG_NUMA
6413
6414static const struct cpumask *sd_numa_mask(int cpu)
6415{
6416 return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)];
6417}
6418
6419static void sched_numa_warn(const char *str)
6420{
6421 static int done = false;
6422 int i,j;
6423
6424 if (done)
6425 return;
6426
6427 done = true;
6428
6429 printk(KERN_WARNING "ERROR: %s\n\n", str);
6430
6431 for (i = 0; i < nr_node_ids; i++) {
6432 printk(KERN_WARNING " ");
6433 for (j = 0; j < nr_node_ids; j++)
6434 printk(KERN_CONT "%02d ", node_distance(i,j));
6435 printk(KERN_CONT "\n");
6436 }
6437 printk(KERN_WARNING "\n");
6438}
6439
6440bool find_numa_distance(int distance)
6441{
6442 int i;
6443
6444 if (distance == node_distance(0, 0))
6445 return true;
6446
6447 for (i = 0; i < sched_domains_numa_levels; i++) {
6448 if (sched_domains_numa_distance[i] == distance)
6449 return true;
6450 }
6451
6452 return false;
6453}
6454
6455/*
6456 * A system can have three types of NUMA topology:
6457 * NUMA_DIRECT: all nodes are directly connected, or not a NUMA system
6458 * NUMA_GLUELESS_MESH: some nodes reachable through intermediary nodes
6459 * NUMA_BACKPLANE: nodes can reach other nodes through a backplane
6460 *
6461 * The difference between a glueless mesh topology and a backplane
6462 * topology lies in whether communication between not directly
6463 * connected nodes goes through intermediary nodes (where programs
6464 * could run), or through backplane controllers. This affects
6465 * placement of programs.
6466 *
6467 * The type of topology can be discerned with the following tests:
6468 * - If the maximum distance between any nodes is 1 hop, the system
6469 * is directly connected.
6470 * - If for two nodes A and B, located N > 1 hops away from each other,
6471 * there is an intermediary node C, which is < N hops away from both
6472 * nodes A and B, the system is a glueless mesh.
6473 */
6474static void init_numa_topology_type(void)
6475{
6476 int a, b, c, n;
6477
6478 n = sched_max_numa_distance;
6479
6480 if (sched_domains_numa_levels <= 1) {
6481 sched_numa_topology_type = NUMA_DIRECT;
6482 return;
6483 }
6484
6485 for_each_online_node(a) {
6486 for_each_online_node(b) {
6487 /* Find two nodes furthest removed from each other. */
6488 if (node_distance(a, b) < n)
6489 continue;
6490
6491 /* Is there an intermediary node between a and b? */
6492 for_each_online_node(c) {
6493 if (node_distance(a, c) < n &&
6494 node_distance(b, c) < n) {
6495 sched_numa_topology_type =
6496 NUMA_GLUELESS_MESH;
6497 return;
6498 }
6499 }
6500
6501 sched_numa_topology_type = NUMA_BACKPLANE;
6502 return;
6503 }
6504 }
6505}
6506
6507static void sched_init_numa(void)
6508{
6509 int next_distance, curr_distance = node_distance(0, 0);
6510 struct sched_domain_topology_level *tl;
6511 int level = 0;
6512 int i, j, k;
6513
6514 sched_domains_numa_distance = kzalloc(sizeof(int) * nr_node_ids, GFP_KERNEL);
6515 if (!sched_domains_numa_distance)
6516 return;
6517
6518 /*
6519 * O(nr_nodes^2) deduplicating selection sort -- in order to find the
6520 * unique distances in the node_distance() table.
6521 *
6522 * Assumes node_distance(0,j) includes all distances in
6523 * node_distance(i,j) in order to avoid cubic time.
6524 */
6525 next_distance = curr_distance;
6526 for (i = 0; i < nr_node_ids; i++) {
6527 for (j = 0; j < nr_node_ids; j++) {
6528 for (k = 0; k < nr_node_ids; k++) {
6529 int distance = node_distance(i, k);
6530
6531 if (distance > curr_distance &&
6532 (distance < next_distance ||
6533 next_distance == curr_distance))
6534 next_distance = distance;
6535
6536 /*
6537 * While not a strong assumption it would be nice to know
6538 * about cases where if node A is connected to B, B is not
6539 * equally connected to A.
6540 */
6541 if (sched_debug() && node_distance(k, i) != distance)
6542 sched_numa_warn("Node-distance not symmetric");
6543
6544 if (sched_debug() && i && !find_numa_distance(distance))
6545 sched_numa_warn("Node-0 not representative");
6546 }
6547 if (next_distance != curr_distance) {
6548 sched_domains_numa_distance[level++] = next_distance;
6549 sched_domains_numa_levels = level;
6550 curr_distance = next_distance;
6551 } else break;
6552 }
6553
6554 /*
6555 * In case of sched_debug() we verify the above assumption.
6556 */
6557 if (!sched_debug())
6558 break;
6559 }
6560
6561 if (!level)
6562 return;
6563
6564 /*
6565 * 'level' contains the number of unique distances, excluding the
6566 * identity distance node_distance(i,i).
6567 *
6568 * The sched_domains_numa_distance[] array includes the actual distance
6569 * numbers.
6570 */
6571
6572 /*
6573 * Here, we should temporarily reset sched_domains_numa_levels to 0.
6574 * If it fails to allocate memory for array sched_domains_numa_masks[][],
6575 * the array will contain less then 'level' members. This could be
6576 * dangerous when we use it to iterate array sched_domains_numa_masks[][]
6577 * in other functions.
6578 *
6579 * We reset it to 'level' at the end of this function.
6580 */
6581 sched_domains_numa_levels = 0;
6582
6583 sched_domains_numa_masks = kzalloc(sizeof(void *) * level, GFP_KERNEL);
6584 if (!sched_domains_numa_masks)
6585 return;
6586
6587 /*
6588 * Now for each level, construct a mask per node which contains all
6589 * cpus of nodes that are that many hops away from us.
6590 */
6591 for (i = 0; i < level; i++) {
6592 sched_domains_numa_masks[i] =
6593 kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL);
6594 if (!sched_domains_numa_masks[i])
6595 return;
6596
6597 for (j = 0; j < nr_node_ids; j++) {
6598 struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL);
6599 if (!mask)
6600 return;
6601
6602 sched_domains_numa_masks[i][j] = mask;
6603
6604 for_each_node(k) {
6605 if (node_distance(j, k) > sched_domains_numa_distance[i])
6606 continue;
6607
6608 cpumask_or(mask, mask, cpumask_of_node(k));
6609 }
6610 }
6611 }
6612
6613 /* Compute default topology size */
6614 for (i = 0; sched_domain_topology[i].mask; i++);
6615
6616 tl = kzalloc((i + level + 1) *
6617 sizeof(struct sched_domain_topology_level), GFP_KERNEL);
6618 if (!tl)
6619 return;
6620
6621 /*
6622 * Copy the default topology bits..
6623 */
6624 for (i = 0; sched_domain_topology[i].mask; i++)
6625 tl[i] = sched_domain_topology[i];
6626
6627 /*
6628 * .. and append 'j' levels of NUMA goodness.
6629 */
6630 for (j = 0; j < level; i++, j++) {
6631 tl[i] = (struct sched_domain_topology_level){
6632 .mask = sd_numa_mask,
6633 .sd_flags = cpu_numa_flags,
6634 .flags = SDTL_OVERLAP,
6635 .numa_level = j,
6636 SD_INIT_NAME(NUMA)
6637 };
6638 }
6639
6640 sched_domain_topology = tl;
6641
6642 sched_domains_numa_levels = level;
6643 sched_max_numa_distance = sched_domains_numa_distance[level - 1];
6644
6645 init_numa_topology_type();
6646}
6647
6648static void sched_domains_numa_masks_set(int cpu)
6649{
6650 int i, j;
6651 int node = cpu_to_node(cpu);
6652
6653 for (i = 0; i < sched_domains_numa_levels; i++) {
6654 for (j = 0; j < nr_node_ids; j++) {
6655 if (node_distance(j, node) <= sched_domains_numa_distance[i])
6656 cpumask_set_cpu(cpu, sched_domains_numa_masks[i][j]);
6657 }
6658 }
6659}
6660
6661static void sched_domains_numa_masks_clear(int cpu)
6662{
6663 int i, j;
6664 for (i = 0; i < sched_domains_numa_levels; i++) {
6665 for (j = 0; j < nr_node_ids; j++)
6666 cpumask_clear_cpu(cpu, sched_domains_numa_masks[i][j]);
6667 }
6668}
6669
6670/*
6671 * Update sched_domains_numa_masks[level][node] array when new cpus
6672 * are onlined.
6673 */
6674static int sched_domains_numa_masks_update(struct notifier_block *nfb,
6675 unsigned long action,
6676 void *hcpu)
6677{
6678 int cpu = (long)hcpu;
6679
6680 switch (action & ~CPU_TASKS_FROZEN) {
6681 case CPU_ONLINE:
6682 sched_domains_numa_masks_set(cpu);
6683 break;
6684
6685 case CPU_DEAD:
6686 sched_domains_numa_masks_clear(cpu);
6687 break;
6688
6689 default:
6690 return NOTIFY_DONE;
6691 }
6692
6693 return NOTIFY_OK;
6694}
6695#else
6696static inline void sched_init_numa(void)
6697{
6698}
6699
6700static int sched_domains_numa_masks_update(struct notifier_block *nfb,
6701 unsigned long action,
6702 void *hcpu)
6703{
6704 return 0;
6705}
6706#endif /* CONFIG_NUMA */
6707
6708static int __sdt_alloc(const struct cpumask *cpu_map)
6709{
6710 struct sched_domain_topology_level *tl;
6711 int j;
6712
6713 for_each_sd_topology(tl) {
6714 struct sd_data *sdd = &tl->data;
6715
6716 sdd->sd = alloc_percpu(struct sched_domain *);
6717 if (!sdd->sd)
6718 return -ENOMEM;
6719
6720 sdd->sg = alloc_percpu(struct sched_group *);
6721 if (!sdd->sg)
6722 return -ENOMEM;
6723
6724 sdd->sgc = alloc_percpu(struct sched_group_capacity *);
6725 if (!sdd->sgc)
6726 return -ENOMEM;
6727
6728 for_each_cpu(j, cpu_map) {
6729 struct sched_domain *sd;
6730 struct sched_group *sg;
6731 struct sched_group_capacity *sgc;
6732
6733 sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(),
6734 GFP_KERNEL, cpu_to_node(j));
6735 if (!sd)
6736 return -ENOMEM;
6737
6738 *per_cpu_ptr(sdd->sd, j) = sd;
6739
6740 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
6741 GFP_KERNEL, cpu_to_node(j));
6742 if (!sg)
6743 return -ENOMEM;
6744
6745 sg->next = sg;
6746
6747 *per_cpu_ptr(sdd->sg, j) = sg;
6748
6749 sgc = kzalloc_node(sizeof(struct sched_group_capacity) + cpumask_size(),
6750 GFP_KERNEL, cpu_to_node(j));
6751 if (!sgc)
6752 return -ENOMEM;
6753
6754 *per_cpu_ptr(sdd->sgc, j) = sgc;
6755 }
6756 }
6757
6758 return 0;
6759}
6760
6761static void __sdt_free(const struct cpumask *cpu_map)
6762{
6763 struct sched_domain_topology_level *tl;
6764 int j;
6765
6766 for_each_sd_topology(tl) {
6767 struct sd_data *sdd = &tl->data;
6768
6769 for_each_cpu(j, cpu_map) {
6770 struct sched_domain *sd;
6771
6772 if (sdd->sd) {
6773 sd = *per_cpu_ptr(sdd->sd, j);
6774 if (sd && (sd->flags & SD_OVERLAP))
6775 free_sched_groups(sd->groups, 0);
6776 kfree(*per_cpu_ptr(sdd->sd, j));
6777 }
6778
6779 if (sdd->sg)
6780 kfree(*per_cpu_ptr(sdd->sg, j));
6781 if (sdd->sgc)
6782 kfree(*per_cpu_ptr(sdd->sgc, j));
6783 }
6784 free_percpu(sdd->sd);
6785 sdd->sd = NULL;
6786 free_percpu(sdd->sg);
6787 sdd->sg = NULL;
6788 free_percpu(sdd->sgc);
6789 sdd->sgc = NULL;
6790 }
6791}
6792
6793struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl,
6794 const struct cpumask *cpu_map, struct sched_domain_attr *attr,
6795 struct sched_domain *child, int cpu)
6796{
6797 struct sched_domain *sd = sd_init(tl, cpu);
6798 if (!sd)
6799 return child;
6800
6801 cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu));
6802 if (child) {
6803 sd->level = child->level + 1;
6804 sched_domain_level_max = max(sched_domain_level_max, sd->level);
6805 child->parent = sd;
6806 sd->child = child;
6807
6808 if (!cpumask_subset(sched_domain_span(child),
6809 sched_domain_span(sd))) {
6810 pr_err("BUG: arch topology borken\n");
6811#ifdef CONFIG_SCHED_DEBUG
6812 pr_err(" the %s domain not a subset of the %s domain\n",
6813 child->name, sd->name);
6814#endif
6815 /* Fixup, ensure @sd has at least @child cpus. */
6816 cpumask_or(sched_domain_span(sd),
6817 sched_domain_span(sd),
6818 sched_domain_span(child));
6819 }
6820
6821 }
6822 set_domain_attribute(sd, attr);
6823
6824 return sd;
6825}
6826
6827/*
6828 * Build sched domains for a given set of cpus and attach the sched domains
6829 * to the individual cpus
6830 */
6831static int build_sched_domains(const struct cpumask *cpu_map,
6832 struct sched_domain_attr *attr)
6833{
6834 enum s_alloc alloc_state;
6835 struct sched_domain *sd;
6836 struct s_data d;
6837 int i, ret = -ENOMEM;
6838
6839 alloc_state = __visit_domain_allocation_hell(&d, cpu_map);
6840 if (alloc_state != sa_rootdomain)
6841 goto error;
6842
6843 /* Set up domains for cpus specified by the cpu_map. */
6844 for_each_cpu(i, cpu_map) {
6845 struct sched_domain_topology_level *tl;
6846
6847 sd = NULL;
6848 for_each_sd_topology(tl) {
6849 sd = build_sched_domain(tl, cpu_map, attr, sd, i);
6850 if (tl == sched_domain_topology)
6851 *per_cpu_ptr(d.sd, i) = sd;
6852 if (tl->flags & SDTL_OVERLAP || sched_feat(FORCE_SD_OVERLAP))
6853 sd->flags |= SD_OVERLAP;
6854 if (cpumask_equal(cpu_map, sched_domain_span(sd)))
6855 break;
6856 }
6857 }
6858
6859 /* Build the groups for the domains */
6860 for_each_cpu(i, cpu_map) {
6861 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
6862 sd->span_weight = cpumask_weight(sched_domain_span(sd));
6863 if (sd->flags & SD_OVERLAP) {
6864 if (build_overlap_sched_groups(sd, i))
6865 goto error;
6866 } else {
6867 if (build_sched_groups(sd, i))
6868 goto error;
6869 }
6870 }
6871 }
6872
6873 /* Calculate CPU capacity for physical packages and nodes */
6874 for (i = nr_cpumask_bits-1; i >= 0; i--) {
6875 if (!cpumask_test_cpu(i, cpu_map))
6876 continue;
6877
6878 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
6879 claim_allocations(i, sd);
6880 init_sched_groups_capacity(i, sd);
6881 }
6882 }
6883
6884 /* Attach the domains */
6885 rcu_read_lock();
6886 for_each_cpu(i, cpu_map) {
6887 sd = *per_cpu_ptr(d.sd, i);
6888 cpu_attach_domain(sd, d.rd, i);
6889 }
6890 rcu_read_unlock();
6891
6892 ret = 0;
6893error:
6894 __free_domain_allocs(&d, alloc_state, cpu_map);
6895 return ret;
6896}
6897
6898static cpumask_var_t *doms_cur; /* current sched domains */
6899static int ndoms_cur; /* number of sched domains in 'doms_cur' */
6900static struct sched_domain_attr *dattr_cur;
6901 /* attribues of custom domains in 'doms_cur' */
6902
6903/*
6904 * Special case: If a kmalloc of a doms_cur partition (array of
6905 * cpumask) fails, then fallback to a single sched domain,
6906 * as determined by the single cpumask fallback_doms.
6907 */
6908static cpumask_var_t fallback_doms;
6909
6910/*
6911 * arch_update_cpu_topology lets virtualized architectures update the
6912 * cpu core maps. It is supposed to return 1 if the topology changed
6913 * or 0 if it stayed the same.
6914 */
6915int __weak arch_update_cpu_topology(void)
6916{
6917 return 0;
6918}
6919
6920cpumask_var_t *alloc_sched_domains(unsigned int ndoms)
6921{
6922 int i;
6923 cpumask_var_t *doms;
6924
6925 doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL);
6926 if (!doms)
6927 return NULL;
6928 for (i = 0; i < ndoms; i++) {
6929 if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) {
6930 free_sched_domains(doms, i);
6931 return NULL;
6932 }
6933 }
6934 return doms;
6935}
6936
6937void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms)
6938{
6939 unsigned int i;
6940 for (i = 0; i < ndoms; i++)
6941 free_cpumask_var(doms[i]);
6942 kfree(doms);
6943}
6944
6945/*
6946 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
6947 * For now this just excludes isolated cpus, but could be used to
6948 * exclude other special cases in the future.
6949 */
6950static int init_sched_domains(const struct cpumask *cpu_map)
6951{
6952 int err;
6953
6954 arch_update_cpu_topology();
6955 ndoms_cur = 1;
6956 doms_cur = alloc_sched_domains(ndoms_cur);
6957 if (!doms_cur)
6958 doms_cur = &fallback_doms;
6959 cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map);
6960 err = build_sched_domains(doms_cur[0], NULL);
6961 register_sched_domain_sysctl();
6962
6963 return err;
6964}
6965
6966/*
6967 * Detach sched domains from a group of cpus specified in cpu_map
6968 * These cpus will now be attached to the NULL domain
6969 */
6970static void detach_destroy_domains(const struct cpumask *cpu_map)
6971{
6972 int i;
6973
6974 rcu_read_lock();
6975 for_each_cpu(i, cpu_map)
6976 cpu_attach_domain(NULL, &def_root_domain, i);
6977 rcu_read_unlock();
6978}
6979
6980/* handle null as "default" */
6981static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
6982 struct sched_domain_attr *new, int idx_new)
6983{
6984 struct sched_domain_attr tmp;
6985
6986 /* fast path */
6987 if (!new && !cur)
6988 return 1;
6989
6990 tmp = SD_ATTR_INIT;
6991 return !memcmp(cur ? (cur + idx_cur) : &tmp,
6992 new ? (new + idx_new) : &tmp,
6993 sizeof(struct sched_domain_attr));
6994}
6995
6996/*
6997 * Partition sched domains as specified by the 'ndoms_new'
6998 * cpumasks in the array doms_new[] of cpumasks. This compares
6999 * doms_new[] to the current sched domain partitioning, doms_cur[].
7000 * It destroys each deleted domain and builds each new domain.
7001 *
7002 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
7003 * The masks don't intersect (don't overlap.) We should setup one
7004 * sched domain for each mask. CPUs not in any of the cpumasks will
7005 * not be load balanced. If the same cpumask appears both in the
7006 * current 'doms_cur' domains and in the new 'doms_new', we can leave
7007 * it as it is.
7008 *
7009 * The passed in 'doms_new' should be allocated using
7010 * alloc_sched_domains. This routine takes ownership of it and will
7011 * free_sched_domains it when done with it. If the caller failed the
7012 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
7013 * and partition_sched_domains() will fallback to the single partition
7014 * 'fallback_doms', it also forces the domains to be rebuilt.
7015 *
7016 * If doms_new == NULL it will be replaced with cpu_online_mask.
7017 * ndoms_new == 0 is a special case for destroying existing domains,
7018 * and it will not create the default domain.
7019 *
7020 * Call with hotplug lock held
7021 */
7022void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
7023 struct sched_domain_attr *dattr_new)
7024{
7025 int i, j, n;
7026 int new_topology;
7027
7028 mutex_lock(&sched_domains_mutex);
7029
7030 /* always unregister in case we don't destroy any domains */
7031 unregister_sched_domain_sysctl();
7032
7033 /* Let architecture update cpu core mappings. */
7034 new_topology = arch_update_cpu_topology();
7035
7036 n = doms_new ? ndoms_new : 0;
7037
7038 /* Destroy deleted domains */
7039 for (i = 0; i < ndoms_cur; i++) {
7040 for (j = 0; j < n && !new_topology; j++) {
7041 if (cpumask_equal(doms_cur[i], doms_new[j])
7042 && dattrs_equal(dattr_cur, i, dattr_new, j))
7043 goto match1;
7044 }
7045 /* no match - a current sched domain not in new doms_new[] */
7046 detach_destroy_domains(doms_cur[i]);
7047match1:
7048 ;
7049 }
7050
7051 n = ndoms_cur;
7052 if (doms_new == NULL) {
7053 n = 0;
7054 doms_new = &fallback_doms;
7055 cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map);
7056 WARN_ON_ONCE(dattr_new);
7057 }
7058
7059 /* Build new domains */
7060 for (i = 0; i < ndoms_new; i++) {
7061 for (j = 0; j < n && !new_topology; j++) {
7062 if (cpumask_equal(doms_new[i], doms_cur[j])
7063 && dattrs_equal(dattr_new, i, dattr_cur, j))
7064 goto match2;
7065 }
7066 /* no match - add a new doms_new */
7067 build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL);
7068match2:
7069 ;
7070 }
7071
7072 /* Remember the new sched domains */
7073 if (doms_cur != &fallback_doms)
7074 free_sched_domains(doms_cur, ndoms_cur);
7075 kfree(dattr_cur); /* kfree(NULL) is safe */
7076 doms_cur = doms_new;
7077 dattr_cur = dattr_new;
7078 ndoms_cur = ndoms_new;
7079
7080 register_sched_domain_sysctl();
7081
7082 mutex_unlock(&sched_domains_mutex);
7083}
7084
7085static int num_cpus_frozen; /* used to mark begin/end of suspend/resume */
7086
7087/*
7088 * Update cpusets according to cpu_active mask. If cpusets are
7089 * disabled, cpuset_update_active_cpus() becomes a simple wrapper
7090 * around partition_sched_domains().
7091 *
7092 * If we come here as part of a suspend/resume, don't touch cpusets because we
7093 * want to restore it back to its original state upon resume anyway.
7094 */
7095static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action,
7096 void *hcpu)
7097{
7098 switch (action) {
7099 case CPU_ONLINE_FROZEN:
7100 case CPU_DOWN_FAILED_FROZEN:
7101
7102 /*
7103 * num_cpus_frozen tracks how many CPUs are involved in suspend
7104 * resume sequence. As long as this is not the last online
7105 * operation in the resume sequence, just build a single sched
7106 * domain, ignoring cpusets.
7107 */
7108 num_cpus_frozen--;
7109 if (likely(num_cpus_frozen)) {
7110 partition_sched_domains(1, NULL, NULL);
7111 break;
7112 }
7113
7114 /*
7115 * This is the last CPU online operation. So fall through and
7116 * restore the original sched domains by considering the
7117 * cpuset configurations.
7118 */
7119
7120 case CPU_ONLINE:
7121 cpuset_update_active_cpus(true);
7122 break;
7123 default:
7124 return NOTIFY_DONE;
7125 }
7126 return NOTIFY_OK;
7127}
7128
7129static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action,
7130 void *hcpu)
7131{
7132 unsigned long flags;
7133 long cpu = (long)hcpu;
7134 struct dl_bw *dl_b;
7135 bool overflow;
7136 int cpus;
7137
7138 switch (action) {
7139 case CPU_DOWN_PREPARE:
7140 rcu_read_lock_sched();
7141 dl_b = dl_bw_of(cpu);
7142
7143 raw_spin_lock_irqsave(&dl_b->lock, flags);
7144 cpus = dl_bw_cpus(cpu);
7145 overflow = __dl_overflow(dl_b, cpus, 0, 0);
7146 raw_spin_unlock_irqrestore(&dl_b->lock, flags);
7147
7148 rcu_read_unlock_sched();
7149
7150 if (overflow)
7151 return notifier_from_errno(-EBUSY);
7152 cpuset_update_active_cpus(false);
7153 break;
7154 case CPU_DOWN_PREPARE_FROZEN:
7155 num_cpus_frozen++;
7156 partition_sched_domains(1, NULL, NULL);
7157 break;
7158 default:
7159 return NOTIFY_DONE;
7160 }
7161 return NOTIFY_OK;
7162}
7163
7164void __init sched_init_smp(void)
7165{
7166 cpumask_var_t non_isolated_cpus;
7167
7168 alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL);
7169 alloc_cpumask_var(&fallback_doms, GFP_KERNEL);
7170
7171 sched_init_numa();
7172
7173 /*
7174 * There's no userspace yet to cause hotplug operations; hence all the
7175 * cpu masks are stable and all blatant races in the below code cannot
7176 * happen.
7177 */
7178 mutex_lock(&sched_domains_mutex);
7179 init_sched_domains(cpu_active_mask);
7180 cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map);
7181 if (cpumask_empty(non_isolated_cpus))
7182 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus);
7183 mutex_unlock(&sched_domains_mutex);
7184
7185 hotcpu_notifier(sched_domains_numa_masks_update, CPU_PRI_SCHED_ACTIVE);
7186 hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE);
7187 hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE);
7188
7189 init_hrtick();
7190
7191 /* Move init over to a non-isolated CPU */
7192 if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0)
7193 BUG();
7194 sched_init_granularity();
7195 free_cpumask_var(non_isolated_cpus);
7196
7197 init_sched_rt_class();
7198 init_sched_dl_class();
7199}
7200#else
7201void __init sched_init_smp(void)
7202{
7203 sched_init_granularity();
7204}
7205#endif /* CONFIG_SMP */
7206
7207int in_sched_functions(unsigned long addr)
7208{
7209 return in_lock_functions(addr) ||
7210 (addr >= (unsigned long)__sched_text_start
7211 && addr < (unsigned long)__sched_text_end);
7212}
7213
7214#ifdef CONFIG_CGROUP_SCHED
7215/*
7216 * Default task group.
7217 * Every task in system belongs to this group at bootup.
7218 */
7219struct task_group root_task_group;
7220LIST_HEAD(task_groups);
7221
7222/* Cacheline aligned slab cache for task_group */
7223static struct kmem_cache *task_group_cache __read_mostly;
7224#endif
7225
7226DECLARE_PER_CPU(cpumask_var_t, load_balance_mask);
7227
7228void __init sched_init(void)
7229{
7230 int i, j;
7231 unsigned long alloc_size = 0, ptr;
7232
7233#ifdef CONFIG_FAIR_GROUP_SCHED
7234 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
7235#endif
7236#ifdef CONFIG_RT_GROUP_SCHED
7237 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
7238#endif
7239 if (alloc_size) {
7240 ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT);
7241
7242#ifdef CONFIG_FAIR_GROUP_SCHED
7243 root_task_group.se = (struct sched_entity **)ptr;
7244 ptr += nr_cpu_ids * sizeof(void **);
7245
7246 root_task_group.cfs_rq = (struct cfs_rq **)ptr;
7247 ptr += nr_cpu_ids * sizeof(void **);
7248
7249#endif /* CONFIG_FAIR_GROUP_SCHED */
7250#ifdef CONFIG_RT_GROUP_SCHED
7251 root_task_group.rt_se = (struct sched_rt_entity **)ptr;
7252 ptr += nr_cpu_ids * sizeof(void **);
7253
7254 root_task_group.rt_rq = (struct rt_rq **)ptr;
7255 ptr += nr_cpu_ids * sizeof(void **);
7256
7257#endif /* CONFIG_RT_GROUP_SCHED */
7258 }
7259#ifdef CONFIG_CPUMASK_OFFSTACK
7260 for_each_possible_cpu(i) {
7261 per_cpu(load_balance_mask, i) = (cpumask_var_t)kzalloc_node(
7262 cpumask_size(), GFP_KERNEL, cpu_to_node(i));
7263 }
7264#endif /* CONFIG_CPUMASK_OFFSTACK */
7265
7266 init_rt_bandwidth(&def_rt_bandwidth,
7267 global_rt_period(), global_rt_runtime());
7268 init_dl_bandwidth(&def_dl_bandwidth,
7269 global_rt_period(), global_rt_runtime());
7270
7271#ifdef CONFIG_SMP
7272 init_defrootdomain();
7273#endif
7274
7275#ifdef CONFIG_RT_GROUP_SCHED
7276 init_rt_bandwidth(&root_task_group.rt_bandwidth,
7277 global_rt_period(), global_rt_runtime());
7278#endif /* CONFIG_RT_GROUP_SCHED */
7279
7280#ifdef CONFIG_CGROUP_SCHED
7281 task_group_cache = KMEM_CACHE(task_group, 0);
7282
7283 list_add(&root_task_group.list, &task_groups);
7284 INIT_LIST_HEAD(&root_task_group.children);
7285 INIT_LIST_HEAD(&root_task_group.siblings);
7286 autogroup_init(&init_task);
7287#endif /* CONFIG_CGROUP_SCHED */
7288
7289 for_each_possible_cpu(i) {
7290 struct rq *rq;
7291
7292 rq = cpu_rq(i);
7293 raw_spin_lock_init(&rq->lock);
7294 rq->nr_running = 0;
7295 rq->calc_load_active = 0;
7296 rq->calc_load_update = jiffies + LOAD_FREQ;
7297 init_cfs_rq(&rq->cfs);
7298 init_rt_rq(&rq->rt);
7299 init_dl_rq(&rq->dl);
7300#ifdef CONFIG_FAIR_GROUP_SCHED
7301 root_task_group.shares = ROOT_TASK_GROUP_LOAD;
7302 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
7303 /*
7304 * How much cpu bandwidth does root_task_group get?
7305 *
7306 * In case of task-groups formed thr' the cgroup filesystem, it
7307 * gets 100% of the cpu resources in the system. This overall
7308 * system cpu resource is divided among the tasks of
7309 * root_task_group and its child task-groups in a fair manner,
7310 * based on each entity's (task or task-group's) weight
7311 * (se->load.weight).
7312 *
7313 * In other words, if root_task_group has 10 tasks of weight
7314 * 1024) and two child groups A0 and A1 (of weight 1024 each),
7315 * then A0's share of the cpu resource is:
7316 *
7317 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
7318 *
7319 * We achieve this by letting root_task_group's tasks sit
7320 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
7321 */
7322 init_cfs_bandwidth(&root_task_group.cfs_bandwidth);
7323 init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL);
7324#endif /* CONFIG_FAIR_GROUP_SCHED */
7325
7326 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime;
7327#ifdef CONFIG_RT_GROUP_SCHED
7328 init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL);
7329#endif
7330
7331 for (j = 0; j < CPU_LOAD_IDX_MAX; j++)
7332 rq->cpu_load[j] = 0;
7333
7334 rq->last_load_update_tick = jiffies;
7335
7336#ifdef CONFIG_SMP
7337 rq->sd = NULL;
7338 rq->rd = NULL;
7339 rq->cpu_capacity = rq->cpu_capacity_orig = SCHED_CAPACITY_SCALE;
7340 rq->balance_callback = NULL;
7341 rq->active_balance = 0;
7342 rq->next_balance = jiffies;
7343 rq->push_cpu = 0;
7344 rq->cpu = i;
7345 rq->online = 0;
7346 rq->idle_stamp = 0;
7347 rq->avg_idle = 2*sysctl_sched_migration_cost;
7348 rq->max_idle_balance_cost = sysctl_sched_migration_cost;
7349
7350 INIT_LIST_HEAD(&rq->cfs_tasks);
7351
7352 rq_attach_root(rq, &def_root_domain);
7353#ifdef CONFIG_NO_HZ_COMMON
7354 rq->nohz_flags = 0;
7355#endif
7356#ifdef CONFIG_NO_HZ_FULL
7357 rq->last_sched_tick = 0;
7358#endif
7359#endif
7360 init_rq_hrtick(rq);
7361 atomic_set(&rq->nr_iowait, 0);
7362 }
7363
7364 set_load_weight(&init_task);
7365
7366#ifdef CONFIG_PREEMPT_NOTIFIERS
7367 INIT_HLIST_HEAD(&init_task.preempt_notifiers);
7368#endif
7369
7370 /*
7371 * The boot idle thread does lazy MMU switching as well:
7372 */
7373 atomic_inc(&init_mm.mm_count);
7374 enter_lazy_tlb(&init_mm, current);
7375
7376 /*
7377 * During early bootup we pretend to be a normal task:
7378 */
7379 current->sched_class = &fair_sched_class;
7380
7381 /*
7382 * Make us the idle thread. Technically, schedule() should not be
7383 * called from this thread, however somewhere below it might be,
7384 * but because we are the idle thread, we just pick up running again
7385 * when this runqueue becomes "idle".
7386 */
7387 init_idle(current, smp_processor_id());
7388
7389 calc_load_update = jiffies + LOAD_FREQ;
7390
7391#ifdef CONFIG_SMP
7392 zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT);
7393 /* May be allocated at isolcpus cmdline parse time */
7394 if (cpu_isolated_map == NULL)
7395 zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
7396 idle_thread_set_boot_cpu();
7397 set_cpu_rq_start_time();
7398#endif
7399 init_sched_fair_class();
7400
7401 scheduler_running = 1;
7402}
7403
7404#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
7405static inline int preempt_count_equals(int preempt_offset)
7406{
7407 int nested = preempt_count() + rcu_preempt_depth();
7408
7409 return (nested == preempt_offset);
7410}
7411
7412void __might_sleep(const char *file, int line, int preempt_offset)
7413{
7414 /*
7415 * Blocking primitives will set (and therefore destroy) current->state,
7416 * since we will exit with TASK_RUNNING make sure we enter with it,
7417 * otherwise we will destroy state.
7418 */
7419 WARN_ONCE(current->state != TASK_RUNNING && current->task_state_change,
7420 "do not call blocking ops when !TASK_RUNNING; "
7421 "state=%lx set at [<%p>] %pS\n",
7422 current->state,
7423 (void *)current->task_state_change,
7424 (void *)current->task_state_change);
7425
7426 ___might_sleep(file, line, preempt_offset);
7427}
7428EXPORT_SYMBOL(__might_sleep);
7429
7430void ___might_sleep(const char *file, int line, int preempt_offset)
7431{
7432 static unsigned long prev_jiffy; /* ratelimiting */
7433
7434 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */
7435 if ((preempt_count_equals(preempt_offset) && !irqs_disabled() &&
7436 !is_idle_task(current)) ||
7437 system_state != SYSTEM_RUNNING || oops_in_progress)
7438 return;
7439 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
7440 return;
7441 prev_jiffy = jiffies;
7442
7443 printk(KERN_ERR
7444 "BUG: sleeping function called from invalid context at %s:%d\n",
7445 file, line);
7446 printk(KERN_ERR
7447 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
7448 in_atomic(), irqs_disabled(),
7449 current->pid, current->comm);
7450
7451 if (task_stack_end_corrupted(current))
7452 printk(KERN_EMERG "Thread overran stack, or stack corrupted\n");
7453
7454 debug_show_held_locks(current);
7455 if (irqs_disabled())
7456 print_irqtrace_events(current);
7457#ifdef CONFIG_DEBUG_PREEMPT
7458 if (!preempt_count_equals(preempt_offset)) {
7459 pr_err("Preemption disabled at:");
7460 print_ip_sym(current->preempt_disable_ip);
7461 pr_cont("\n");
7462 }
7463#endif
7464 dump_stack();
7465}
7466EXPORT_SYMBOL(___might_sleep);
7467#endif
7468
7469#ifdef CONFIG_MAGIC_SYSRQ
7470void normalize_rt_tasks(void)
7471{
7472 struct task_struct *g, *p;
7473 struct sched_attr attr = {
7474 .sched_policy = SCHED_NORMAL,
7475 };
7476
7477 read_lock(&tasklist_lock);
7478 for_each_process_thread(g, p) {
7479 /*
7480 * Only normalize user tasks:
7481 */
7482 if (p->flags & PF_KTHREAD)
7483 continue;
7484
7485 p->se.exec_start = 0;
7486#ifdef CONFIG_SCHEDSTATS
7487 p->se.statistics.wait_start = 0;
7488 p->se.statistics.sleep_start = 0;
7489 p->se.statistics.block_start = 0;
7490#endif
7491
7492 if (!dl_task(p) && !rt_task(p)) {
7493 /*
7494 * Renice negative nice level userspace
7495 * tasks back to 0:
7496 */
7497 if (task_nice(p) < 0)
7498 set_user_nice(p, 0);
7499 continue;
7500 }
7501
7502 __sched_setscheduler(p, &attr, false, false);
7503 }
7504 read_unlock(&tasklist_lock);
7505}
7506
7507#endif /* CONFIG_MAGIC_SYSRQ */
7508
7509#if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
7510/*
7511 * These functions are only useful for the IA64 MCA handling, or kdb.
7512 *
7513 * They can only be called when the whole system has been
7514 * stopped - every CPU needs to be quiescent, and no scheduling
7515 * activity can take place. Using them for anything else would
7516 * be a serious bug, and as a result, they aren't even visible
7517 * under any other configuration.
7518 */
7519
7520/**
7521 * curr_task - return the current task for a given cpu.
7522 * @cpu: the processor in question.
7523 *
7524 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7525 *
7526 * Return: The current task for @cpu.
7527 */
7528struct task_struct *curr_task(int cpu)
7529{
7530 return cpu_curr(cpu);
7531}
7532
7533#endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
7534
7535#ifdef CONFIG_IA64
7536/**
7537 * set_curr_task - set the current task for a given cpu.
7538 * @cpu: the processor in question.
7539 * @p: the task pointer to set.
7540 *
7541 * Description: This function must only be used when non-maskable interrupts
7542 * are serviced on a separate stack. It allows the architecture to switch the
7543 * notion of the current task on a cpu in a non-blocking manner. This function
7544 * must be called with all CPU's synchronized, and interrupts disabled, the
7545 * and caller must save the original value of the current task (see
7546 * curr_task() above) and restore that value before reenabling interrupts and
7547 * re-starting the system.
7548 *
7549 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7550 */
7551void set_curr_task(int cpu, struct task_struct *p)
7552{
7553 cpu_curr(cpu) = p;
7554}
7555
7556#endif
7557
7558#ifdef CONFIG_CGROUP_SCHED
7559/* task_group_lock serializes the addition/removal of task groups */
7560static DEFINE_SPINLOCK(task_group_lock);
7561
7562static void sched_free_group(struct task_group *tg)
7563{
7564 free_fair_sched_group(tg);
7565 free_rt_sched_group(tg);
7566 autogroup_free(tg);
7567 kmem_cache_free(task_group_cache, tg);
7568}
7569
7570/* allocate runqueue etc for a new task group */
7571struct task_group *sched_create_group(struct task_group *parent)
7572{
7573 struct task_group *tg;
7574
7575 tg = kmem_cache_alloc(task_group_cache, GFP_KERNEL | __GFP_ZERO);
7576 if (!tg)
7577 return ERR_PTR(-ENOMEM);
7578
7579 if (!alloc_fair_sched_group(tg, parent))
7580 goto err;
7581
7582 if (!alloc_rt_sched_group(tg, parent))
7583 goto err;
7584
7585 return tg;
7586
7587err:
7588 sched_free_group(tg);
7589 return ERR_PTR(-ENOMEM);
7590}
7591
7592void sched_online_group(struct task_group *tg, struct task_group *parent)
7593{
7594 unsigned long flags;
7595
7596 spin_lock_irqsave(&task_group_lock, flags);
7597 list_add_rcu(&tg->list, &task_groups);
7598
7599 WARN_ON(!parent); /* root should already exist */
7600
7601 tg->parent = parent;
7602 INIT_LIST_HEAD(&tg->children);
7603 list_add_rcu(&tg->siblings, &parent->children);
7604 spin_unlock_irqrestore(&task_group_lock, flags);
7605}
7606
7607/* rcu callback to free various structures associated with a task group */
7608static void sched_free_group_rcu(struct rcu_head *rhp)
7609{
7610 /* now it should be safe to free those cfs_rqs */
7611 sched_free_group(container_of(rhp, struct task_group, rcu));
7612}
7613
7614void sched_destroy_group(struct task_group *tg)
7615{
7616 /* wait for possible concurrent references to cfs_rqs complete */
7617 call_rcu(&tg->rcu, sched_free_group_rcu);
7618}
7619
7620void sched_offline_group(struct task_group *tg)
7621{
7622 unsigned long flags;
7623
7624 /* end participation in shares distribution */
7625 unregister_fair_sched_group(tg);
7626
7627 spin_lock_irqsave(&task_group_lock, flags);
7628 list_del_rcu(&tg->list);
7629 list_del_rcu(&tg->siblings);
7630 spin_unlock_irqrestore(&task_group_lock, flags);
7631}
7632
7633/* change task's runqueue when it moves between groups.
7634 * The caller of this function should have put the task in its new group
7635 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
7636 * reflect its new group.
7637 */
7638void sched_move_task(struct task_struct *tsk)
7639{
7640 struct task_group *tg;
7641 int queued, running;
7642 unsigned long flags;
7643 struct rq *rq;
7644
7645 rq = task_rq_lock(tsk, &flags);
7646
7647 running = task_current(rq, tsk);
7648 queued = task_on_rq_queued(tsk);
7649
7650 if (queued)
7651 dequeue_task(rq, tsk, DEQUEUE_SAVE | DEQUEUE_MOVE);
7652 if (unlikely(running))
7653 put_prev_task(rq, tsk);
7654
7655 /*
7656 * All callers are synchronized by task_rq_lock(); we do not use RCU
7657 * which is pointless here. Thus, we pass "true" to task_css_check()
7658 * to prevent lockdep warnings.
7659 */
7660 tg = container_of(task_css_check(tsk, cpu_cgrp_id, true),
7661 struct task_group, css);
7662 tg = autogroup_task_group(tsk, tg);
7663 tsk->sched_task_group = tg;
7664
7665#ifdef CONFIG_FAIR_GROUP_SCHED
7666 if (tsk->sched_class->task_move_group)
7667 tsk->sched_class->task_move_group(tsk);
7668 else
7669#endif
7670 set_task_rq(tsk, task_cpu(tsk));
7671
7672 if (unlikely(running))
7673 tsk->sched_class->set_curr_task(rq);
7674 if (queued)
7675 enqueue_task(rq, tsk, ENQUEUE_RESTORE | ENQUEUE_MOVE);
7676
7677 task_rq_unlock(rq, tsk, &flags);
7678}
7679#endif /* CONFIG_CGROUP_SCHED */
7680
7681#ifdef CONFIG_RT_GROUP_SCHED
7682/*
7683 * Ensure that the real time constraints are schedulable.
7684 */
7685static DEFINE_MUTEX(rt_constraints_mutex);
7686
7687/* Must be called with tasklist_lock held */
7688static inline int tg_has_rt_tasks(struct task_group *tg)
7689{
7690 struct task_struct *g, *p;
7691
7692 /*
7693 * Autogroups do not have RT tasks; see autogroup_create().
7694 */
7695 if (task_group_is_autogroup(tg))
7696 return 0;
7697
7698 for_each_process_thread(g, p) {
7699 if (rt_task(p) && task_group(p) == tg)
7700 return 1;
7701 }
7702
7703 return 0;
7704}
7705
7706struct rt_schedulable_data {
7707 struct task_group *tg;
7708 u64 rt_period;
7709 u64 rt_runtime;
7710};
7711
7712static int tg_rt_schedulable(struct task_group *tg, void *data)
7713{
7714 struct rt_schedulable_data *d = data;
7715 struct task_group *child;
7716 unsigned long total, sum = 0;
7717 u64 period, runtime;
7718
7719 period = ktime_to_ns(tg->rt_bandwidth.rt_period);
7720 runtime = tg->rt_bandwidth.rt_runtime;
7721
7722 if (tg == d->tg) {
7723 period = d->rt_period;
7724 runtime = d->rt_runtime;
7725 }
7726
7727 /*
7728 * Cannot have more runtime than the period.
7729 */
7730 if (runtime > period && runtime != RUNTIME_INF)
7731 return -EINVAL;
7732
7733 /*
7734 * Ensure we don't starve existing RT tasks.
7735 */
7736 if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg))
7737 return -EBUSY;
7738
7739 total = to_ratio(period, runtime);
7740
7741 /*
7742 * Nobody can have more than the global setting allows.
7743 */
7744 if (total > to_ratio(global_rt_period(), global_rt_runtime()))
7745 return -EINVAL;
7746
7747 /*
7748 * The sum of our children's runtime should not exceed our own.
7749 */
7750 list_for_each_entry_rcu(child, &tg->children, siblings) {
7751 period = ktime_to_ns(child->rt_bandwidth.rt_period);
7752 runtime = child->rt_bandwidth.rt_runtime;
7753
7754 if (child == d->tg) {
7755 period = d->rt_period;
7756 runtime = d->rt_runtime;
7757 }
7758
7759 sum += to_ratio(period, runtime);
7760 }
7761
7762 if (sum > total)
7763 return -EINVAL;
7764
7765 return 0;
7766}
7767
7768static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
7769{
7770 int ret;
7771
7772 struct rt_schedulable_data data = {
7773 .tg = tg,
7774 .rt_period = period,
7775 .rt_runtime = runtime,
7776 };
7777
7778 rcu_read_lock();
7779 ret = walk_tg_tree(tg_rt_schedulable, tg_nop, &data);
7780 rcu_read_unlock();
7781
7782 return ret;
7783}
7784
7785static int tg_set_rt_bandwidth(struct task_group *tg,
7786 u64 rt_period, u64 rt_runtime)
7787{
7788 int i, err = 0;
7789
7790 /*
7791 * Disallowing the root group RT runtime is BAD, it would disallow the
7792 * kernel creating (and or operating) RT threads.
7793 */
7794 if (tg == &root_task_group && rt_runtime == 0)
7795 return -EINVAL;
7796
7797 /* No period doesn't make any sense. */
7798 if (rt_period == 0)
7799 return -EINVAL;
7800
7801 mutex_lock(&rt_constraints_mutex);
7802 read_lock(&tasklist_lock);
7803 err = __rt_schedulable(tg, rt_period, rt_runtime);
7804 if (err)
7805 goto unlock;
7806
7807 raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock);
7808 tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period);
7809 tg->rt_bandwidth.rt_runtime = rt_runtime;
7810
7811 for_each_possible_cpu(i) {
7812 struct rt_rq *rt_rq = tg->rt_rq[i];
7813
7814 raw_spin_lock(&rt_rq->rt_runtime_lock);
7815 rt_rq->rt_runtime = rt_runtime;
7816 raw_spin_unlock(&rt_rq->rt_runtime_lock);
7817 }
7818 raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock);
7819unlock:
7820 read_unlock(&tasklist_lock);
7821 mutex_unlock(&rt_constraints_mutex);
7822
7823 return err;
7824}
7825
7826static int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us)
7827{
7828 u64 rt_runtime, rt_period;
7829
7830 rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period);
7831 rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC;
7832 if (rt_runtime_us < 0)
7833 rt_runtime = RUNTIME_INF;
7834
7835 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime);
7836}
7837
7838static long sched_group_rt_runtime(struct task_group *tg)
7839{
7840 u64 rt_runtime_us;
7841
7842 if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF)
7843 return -1;
7844
7845 rt_runtime_us = tg->rt_bandwidth.rt_runtime;
7846 do_div(rt_runtime_us, NSEC_PER_USEC);
7847 return rt_runtime_us;
7848}
7849
7850static int sched_group_set_rt_period(struct task_group *tg, u64 rt_period_us)
7851{
7852 u64 rt_runtime, rt_period;
7853
7854 rt_period = rt_period_us * NSEC_PER_USEC;
7855 rt_runtime = tg->rt_bandwidth.rt_runtime;
7856
7857 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime);
7858}
7859
7860static long sched_group_rt_period(struct task_group *tg)
7861{
7862 u64 rt_period_us;
7863
7864 rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period);
7865 do_div(rt_period_us, NSEC_PER_USEC);
7866 return rt_period_us;
7867}
7868#endif /* CONFIG_RT_GROUP_SCHED */
7869
7870#ifdef CONFIG_RT_GROUP_SCHED
7871static int sched_rt_global_constraints(void)
7872{
7873 int ret = 0;
7874
7875 mutex_lock(&rt_constraints_mutex);
7876 read_lock(&tasklist_lock);
7877 ret = __rt_schedulable(NULL, 0, 0);
7878 read_unlock(&tasklist_lock);
7879 mutex_unlock(&rt_constraints_mutex);
7880
7881 return ret;
7882}
7883
7884static int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk)
7885{
7886 /* Don't accept realtime tasks when there is no way for them to run */
7887 if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0)
7888 return 0;
7889
7890 return 1;
7891}
7892
7893#else /* !CONFIG_RT_GROUP_SCHED */
7894static int sched_rt_global_constraints(void)
7895{
7896 unsigned long flags;
7897 int i, ret = 0;
7898
7899 raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
7900 for_each_possible_cpu(i) {
7901 struct rt_rq *rt_rq = &cpu_rq(i)->rt;
7902
7903 raw_spin_lock(&rt_rq->rt_runtime_lock);
7904 rt_rq->rt_runtime = global_rt_runtime();
7905 raw_spin_unlock(&rt_rq->rt_runtime_lock);
7906 }
7907 raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags);
7908
7909 return ret;
7910}
7911#endif /* CONFIG_RT_GROUP_SCHED */
7912
7913static int sched_dl_global_validate(void)
7914{
7915 u64 runtime = global_rt_runtime();
7916 u64 period = global_rt_period();
7917 u64 new_bw = to_ratio(period, runtime);
7918 struct dl_bw *dl_b;
7919 int cpu, ret = 0;
7920 unsigned long flags;
7921
7922 /*
7923 * Here we want to check the bandwidth not being set to some
7924 * value smaller than the currently allocated bandwidth in
7925 * any of the root_domains.
7926 *
7927 * FIXME: Cycling on all the CPUs is overdoing, but simpler than
7928 * cycling on root_domains... Discussion on different/better
7929 * solutions is welcome!
7930 */
7931 for_each_possible_cpu(cpu) {
7932 rcu_read_lock_sched();
7933 dl_b = dl_bw_of(cpu);
7934
7935 raw_spin_lock_irqsave(&dl_b->lock, flags);
7936 if (new_bw < dl_b->total_bw)
7937 ret = -EBUSY;
7938 raw_spin_unlock_irqrestore(&dl_b->lock, flags);
7939
7940 rcu_read_unlock_sched();
7941
7942 if (ret)
7943 break;
7944 }
7945
7946 return ret;
7947}
7948
7949static void sched_dl_do_global(void)
7950{
7951 u64 new_bw = -1;
7952 struct dl_bw *dl_b;
7953 int cpu;
7954 unsigned long flags;
7955
7956 def_dl_bandwidth.dl_period = global_rt_period();
7957 def_dl_bandwidth.dl_runtime = global_rt_runtime();
7958
7959 if (global_rt_runtime() != RUNTIME_INF)
7960 new_bw = to_ratio(global_rt_period(), global_rt_runtime());
7961
7962 /*
7963 * FIXME: As above...
7964 */
7965 for_each_possible_cpu(cpu) {
7966 rcu_read_lock_sched();
7967 dl_b = dl_bw_of(cpu);
7968
7969 raw_spin_lock_irqsave(&dl_b->lock, flags);
7970 dl_b->bw = new_bw;
7971 raw_spin_unlock_irqrestore(&dl_b->lock, flags);
7972
7973 rcu_read_unlock_sched();
7974 }
7975}
7976
7977static int sched_rt_global_validate(void)
7978{
7979 if (sysctl_sched_rt_period <= 0)
7980 return -EINVAL;
7981
7982 if ((sysctl_sched_rt_runtime != RUNTIME_INF) &&
7983 (sysctl_sched_rt_runtime > sysctl_sched_rt_period))
7984 return -EINVAL;
7985
7986 return 0;
7987}
7988
7989static void sched_rt_do_global(void)
7990{
7991 def_rt_bandwidth.rt_runtime = global_rt_runtime();
7992 def_rt_bandwidth.rt_period = ns_to_ktime(global_rt_period());
7993}
7994
7995int sched_rt_handler(struct ctl_table *table, int write,
7996 void __user *buffer, size_t *lenp,
7997 loff_t *ppos)
7998{
7999 int old_period, old_runtime;
8000 static DEFINE_MUTEX(mutex);
8001 int ret;
8002
8003 mutex_lock(&mutex);
8004 old_period = sysctl_sched_rt_period;
8005 old_runtime = sysctl_sched_rt_runtime;
8006
8007 ret = proc_dointvec(table, write, buffer, lenp, ppos);
8008
8009 if (!ret && write) {
8010 ret = sched_rt_global_validate();
8011 if (ret)
8012 goto undo;
8013
8014 ret = sched_dl_global_validate();
8015 if (ret)
8016 goto undo;
8017
8018 ret = sched_rt_global_constraints();
8019 if (ret)
8020 goto undo;
8021
8022 sched_rt_do_global();
8023 sched_dl_do_global();
8024 }
8025 if (0) {
8026undo:
8027 sysctl_sched_rt_period = old_period;
8028 sysctl_sched_rt_runtime = old_runtime;
8029 }
8030 mutex_unlock(&mutex);
8031
8032 return ret;
8033}
8034
8035int sched_rr_handler(struct ctl_table *table, int write,
8036 void __user *buffer, size_t *lenp,
8037 loff_t *ppos)
8038{
8039 int ret;
8040 static DEFINE_MUTEX(mutex);
8041
8042 mutex_lock(&mutex);
8043 ret = proc_dointvec(table, write, buffer, lenp, ppos);
8044 /* make sure that internally we keep jiffies */
8045 /* also, writing zero resets timeslice to default */
8046 if (!ret && write) {
8047 sched_rr_timeslice = sched_rr_timeslice <= 0 ?
8048 RR_TIMESLICE : msecs_to_jiffies(sched_rr_timeslice);
8049 }
8050 mutex_unlock(&mutex);
8051 return ret;
8052}
8053
8054#ifdef CONFIG_CGROUP_SCHED
8055
8056static inline struct task_group *css_tg(struct cgroup_subsys_state *css)
8057{
8058 return css ? container_of(css, struct task_group, css) : NULL;
8059}
8060
8061static struct cgroup_subsys_state *
8062cpu_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
8063{
8064 struct task_group *parent = css_tg(parent_css);
8065 struct task_group *tg;
8066
8067 if (!parent) {
8068 /* This is early initialization for the top cgroup */
8069 return &root_task_group.css;
8070 }
8071
8072 tg = sched_create_group(parent);
8073 if (IS_ERR(tg))
8074 return ERR_PTR(-ENOMEM);
8075
8076 sched_online_group(tg, parent);
8077
8078 return &tg->css;
8079}
8080
8081static void cpu_cgroup_css_released(struct cgroup_subsys_state *css)
8082{
8083 struct task_group *tg = css_tg(css);
8084
8085 sched_offline_group(tg);
8086}
8087
8088static void cpu_cgroup_css_free(struct cgroup_subsys_state *css)
8089{
8090 struct task_group *tg = css_tg(css);
8091
8092 /*
8093 * Relies on the RCU grace period between css_released() and this.
8094 */
8095 sched_free_group(tg);
8096}
8097
8098static void cpu_cgroup_fork(struct task_struct *task)
8099{
8100 sched_move_task(task);
8101}
8102
8103static int cpu_cgroup_can_attach(struct cgroup_taskset *tset)
8104{
8105 struct task_struct *task;
8106 struct cgroup_subsys_state *css;
8107
8108 cgroup_taskset_for_each(task, css, tset) {
8109#ifdef CONFIG_RT_GROUP_SCHED
8110 if (!sched_rt_can_attach(css_tg(css), task))
8111 return -EINVAL;
8112#else
8113 /* We don't support RT-tasks being in separate groups */
8114 if (task->sched_class != &fair_sched_class)
8115 return -EINVAL;
8116#endif
8117 }
8118 return 0;
8119}
8120
8121static void cpu_cgroup_attach(struct cgroup_taskset *tset)
8122{
8123 struct task_struct *task;
8124 struct cgroup_subsys_state *css;
8125
8126 cgroup_taskset_for_each(task, css, tset)
8127 sched_move_task(task);
8128}
8129
8130#ifdef CONFIG_FAIR_GROUP_SCHED
8131static int cpu_shares_write_u64(struct cgroup_subsys_state *css,
8132 struct cftype *cftype, u64 shareval)
8133{
8134 return sched_group_set_shares(css_tg(css), scale_load(shareval));
8135}
8136
8137static u64 cpu_shares_read_u64(struct cgroup_subsys_state *css,
8138 struct cftype *cft)
8139{
8140 struct task_group *tg = css_tg(css);
8141
8142 return (u64) scale_load_down(tg->shares);
8143}
8144
8145#ifdef CONFIG_CFS_BANDWIDTH
8146static DEFINE_MUTEX(cfs_constraints_mutex);
8147
8148const u64 max_cfs_quota_period = 1 * NSEC_PER_SEC; /* 1s */
8149const u64 min_cfs_quota_period = 1 * NSEC_PER_MSEC; /* 1ms */
8150
8151static int __cfs_schedulable(struct task_group *tg, u64 period, u64 runtime);
8152
8153static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota)
8154{
8155 int i, ret = 0, runtime_enabled, runtime_was_enabled;
8156 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
8157
8158 if (tg == &root_task_group)
8159 return -EINVAL;
8160
8161 /*
8162 * Ensure we have at some amount of bandwidth every period. This is
8163 * to prevent reaching a state of large arrears when throttled via
8164 * entity_tick() resulting in prolonged exit starvation.
8165 */
8166 if (quota < min_cfs_quota_period || period < min_cfs_quota_period)
8167 return -EINVAL;
8168
8169 /*
8170 * Likewise, bound things on the otherside by preventing insane quota
8171 * periods. This also allows us to normalize in computing quota
8172 * feasibility.
8173 */
8174 if (period > max_cfs_quota_period)
8175 return -EINVAL;
8176
8177 /*
8178 * Prevent race between setting of cfs_rq->runtime_enabled and
8179 * unthrottle_offline_cfs_rqs().
8180 */
8181 get_online_cpus();
8182 mutex_lock(&cfs_constraints_mutex);
8183 ret = __cfs_schedulable(tg, period, quota);
8184 if (ret)
8185 goto out_unlock;
8186
8187 runtime_enabled = quota != RUNTIME_INF;
8188 runtime_was_enabled = cfs_b->quota != RUNTIME_INF;
8189 /*
8190 * If we need to toggle cfs_bandwidth_used, off->on must occur
8191 * before making related changes, and on->off must occur afterwards
8192 */
8193 if (runtime_enabled && !runtime_was_enabled)
8194 cfs_bandwidth_usage_inc();
8195 raw_spin_lock_irq(&cfs_b->lock);
8196 cfs_b->period = ns_to_ktime(period);
8197 cfs_b->quota = quota;
8198
8199 __refill_cfs_bandwidth_runtime(cfs_b);
8200 /* restart the period timer (if active) to handle new period expiry */
8201 if (runtime_enabled)
8202 start_cfs_bandwidth(cfs_b);
8203 raw_spin_unlock_irq(&cfs_b->lock);
8204
8205 for_each_online_cpu(i) {
8206 struct cfs_rq *cfs_rq = tg->cfs_rq[i];
8207 struct rq *rq = cfs_rq->rq;
8208
8209 raw_spin_lock_irq(&rq->lock);
8210 cfs_rq->runtime_enabled = runtime_enabled;
8211 cfs_rq->runtime_remaining = 0;
8212
8213 if (cfs_rq->throttled)
8214 unthrottle_cfs_rq(cfs_rq);
8215 raw_spin_unlock_irq(&rq->lock);
8216 }
8217 if (runtime_was_enabled && !runtime_enabled)
8218 cfs_bandwidth_usage_dec();
8219out_unlock:
8220 mutex_unlock(&cfs_constraints_mutex);
8221 put_online_cpus();
8222
8223 return ret;
8224}
8225
8226int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us)
8227{
8228 u64 quota, period;
8229
8230 period = ktime_to_ns(tg->cfs_bandwidth.period);
8231 if (cfs_quota_us < 0)
8232 quota = RUNTIME_INF;
8233 else
8234 quota = (u64)cfs_quota_us * NSEC_PER_USEC;
8235
8236 return tg_set_cfs_bandwidth(tg, period, quota);
8237}
8238
8239long tg_get_cfs_quota(struct task_group *tg)
8240{
8241 u64 quota_us;
8242
8243 if (tg->cfs_bandwidth.quota == RUNTIME_INF)
8244 return -1;
8245
8246 quota_us = tg->cfs_bandwidth.quota;
8247 do_div(quota_us, NSEC_PER_USEC);
8248
8249 return quota_us;
8250}
8251
8252int tg_set_cfs_period(struct task_group *tg, long cfs_period_us)
8253{
8254 u64 quota, period;
8255
8256 period = (u64)cfs_period_us * NSEC_PER_USEC;
8257 quota = tg->cfs_bandwidth.quota;
8258
8259 return tg_set_cfs_bandwidth(tg, period, quota);
8260}
8261
8262long tg_get_cfs_period(struct task_group *tg)
8263{
8264 u64 cfs_period_us;
8265
8266 cfs_period_us = ktime_to_ns(tg->cfs_bandwidth.period);
8267 do_div(cfs_period_us, NSEC_PER_USEC);
8268
8269 return cfs_period_us;
8270}
8271
8272static s64 cpu_cfs_quota_read_s64(struct cgroup_subsys_state *css,
8273 struct cftype *cft)
8274{
8275 return tg_get_cfs_quota(css_tg(css));
8276}
8277
8278static int cpu_cfs_quota_write_s64(struct cgroup_subsys_state *css,
8279 struct cftype *cftype, s64 cfs_quota_us)
8280{
8281 return tg_set_cfs_quota(css_tg(css), cfs_quota_us);
8282}
8283
8284static u64 cpu_cfs_period_read_u64(struct cgroup_subsys_state *css,
8285 struct cftype *cft)
8286{
8287 return tg_get_cfs_period(css_tg(css));
8288}
8289
8290static int cpu_cfs_period_write_u64(struct cgroup_subsys_state *css,
8291 struct cftype *cftype, u64 cfs_period_us)
8292{
8293 return tg_set_cfs_period(css_tg(css), cfs_period_us);
8294}
8295
8296struct cfs_schedulable_data {
8297 struct task_group *tg;
8298 u64 period, quota;
8299};
8300
8301/*
8302 * normalize group quota/period to be quota/max_period
8303 * note: units are usecs
8304 */
8305static u64 normalize_cfs_quota(struct task_group *tg,
8306 struct cfs_schedulable_data *d)
8307{
8308 u64 quota, period;
8309
8310 if (tg == d->tg) {
8311 period = d->period;
8312 quota = d->quota;
8313 } else {
8314 period = tg_get_cfs_period(tg);
8315 quota = tg_get_cfs_quota(tg);
8316 }
8317
8318 /* note: these should typically be equivalent */
8319 if (quota == RUNTIME_INF || quota == -1)
8320 return RUNTIME_INF;
8321
8322 return to_ratio(period, quota);
8323}
8324
8325static int tg_cfs_schedulable_down(struct task_group *tg, void *data)
8326{
8327 struct cfs_schedulable_data *d = data;
8328 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
8329 s64 quota = 0, parent_quota = -1;
8330
8331 if (!tg->parent) {
8332 quota = RUNTIME_INF;
8333 } else {
8334 struct cfs_bandwidth *parent_b = &tg->parent->cfs_bandwidth;
8335
8336 quota = normalize_cfs_quota(tg, d);
8337 parent_quota = parent_b->hierarchical_quota;
8338
8339 /*
8340 * ensure max(child_quota) <= parent_quota, inherit when no
8341 * limit is set
8342 */
8343 if (quota == RUNTIME_INF)
8344 quota = parent_quota;
8345 else if (parent_quota != RUNTIME_INF && quota > parent_quota)
8346 return -EINVAL;
8347 }
8348 cfs_b->hierarchical_quota = quota;
8349
8350 return 0;
8351}
8352
8353static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota)
8354{
8355 int ret;
8356 struct cfs_schedulable_data data = {
8357 .tg = tg,
8358 .period = period,
8359 .quota = quota,
8360 };
8361
8362 if (quota != RUNTIME_INF) {
8363 do_div(data.period, NSEC_PER_USEC);
8364 do_div(data.quota, NSEC_PER_USEC);
8365 }
8366
8367 rcu_read_lock();
8368 ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data);
8369 rcu_read_unlock();
8370
8371 return ret;
8372}
8373
8374static int cpu_stats_show(struct seq_file *sf, void *v)
8375{
8376 struct task_group *tg = css_tg(seq_css(sf));
8377 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
8378
8379 seq_printf(sf, "nr_periods %d\n", cfs_b->nr_periods);
8380 seq_printf(sf, "nr_throttled %d\n", cfs_b->nr_throttled);
8381 seq_printf(sf, "throttled_time %llu\n", cfs_b->throttled_time);
8382
8383 return 0;
8384}
8385#endif /* CONFIG_CFS_BANDWIDTH */
8386#endif /* CONFIG_FAIR_GROUP_SCHED */
8387
8388#ifdef CONFIG_RT_GROUP_SCHED
8389static int cpu_rt_runtime_write(struct cgroup_subsys_state *css,
8390 struct cftype *cft, s64 val)
8391{
8392 return sched_group_set_rt_runtime(css_tg(css), val);
8393}
8394
8395static s64 cpu_rt_runtime_read(struct cgroup_subsys_state *css,
8396 struct cftype *cft)
8397{
8398 return sched_group_rt_runtime(css_tg(css));
8399}
8400
8401static int cpu_rt_period_write_uint(struct cgroup_subsys_state *css,
8402 struct cftype *cftype, u64 rt_period_us)
8403{
8404 return sched_group_set_rt_period(css_tg(css), rt_period_us);
8405}
8406
8407static u64 cpu_rt_period_read_uint(struct cgroup_subsys_state *css,
8408 struct cftype *cft)
8409{
8410 return sched_group_rt_period(css_tg(css));
8411}
8412#endif /* CONFIG_RT_GROUP_SCHED */
8413
8414static struct cftype cpu_files[] = {
8415#ifdef CONFIG_FAIR_GROUP_SCHED
8416 {
8417 .name = "shares",
8418 .read_u64 = cpu_shares_read_u64,
8419 .write_u64 = cpu_shares_write_u64,
8420 },
8421#endif
8422#ifdef CONFIG_CFS_BANDWIDTH
8423 {
8424 .name = "cfs_quota_us",
8425 .read_s64 = cpu_cfs_quota_read_s64,
8426 .write_s64 = cpu_cfs_quota_write_s64,
8427 },
8428 {
8429 .name = "cfs_period_us",
8430 .read_u64 = cpu_cfs_period_read_u64,
8431 .write_u64 = cpu_cfs_period_write_u64,
8432 },
8433 {
8434 .name = "stat",
8435 .seq_show = cpu_stats_show,
8436 },
8437#endif
8438#ifdef CONFIG_RT_GROUP_SCHED
8439 {
8440 .name = "rt_runtime_us",
8441 .read_s64 = cpu_rt_runtime_read,
8442 .write_s64 = cpu_rt_runtime_write,
8443 },
8444 {
8445 .name = "rt_period_us",
8446 .read_u64 = cpu_rt_period_read_uint,
8447 .write_u64 = cpu_rt_period_write_uint,
8448 },
8449#endif
8450 { } /* terminate */
8451};
8452
8453struct cgroup_subsys cpu_cgrp_subsys = {
8454 .css_alloc = cpu_cgroup_css_alloc,
8455 .css_released = cpu_cgroup_css_released,
8456 .css_free = cpu_cgroup_css_free,
8457 .fork = cpu_cgroup_fork,
8458 .can_attach = cpu_cgroup_can_attach,
8459 .attach = cpu_cgroup_attach,
8460 .legacy_cftypes = cpu_files,
8461 .early_init = true,
8462};
8463
8464#endif /* CONFIG_CGROUP_SCHED */
8465
8466void dump_cpu_task(int cpu)
8467{
8468 pr_info("Task dump for CPU %d:\n", cpu);
8469 sched_show_task(cpu_curr(cpu));
8470}
8471
8472/*
8473 * Nice levels are multiplicative, with a gentle 10% change for every
8474 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
8475 * nice 1, it will get ~10% less CPU time than another CPU-bound task
8476 * that remained on nice 0.
8477 *
8478 * The "10% effect" is relative and cumulative: from _any_ nice level,
8479 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
8480 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
8481 * If a task goes up by ~10% and another task goes down by ~10% then
8482 * the relative distance between them is ~25%.)
8483 */
8484const int sched_prio_to_weight[40] = {
8485 /* -20 */ 88761, 71755, 56483, 46273, 36291,
8486 /* -15 */ 29154, 23254, 18705, 14949, 11916,
8487 /* -10 */ 9548, 7620, 6100, 4904, 3906,
8488 /* -5 */ 3121, 2501, 1991, 1586, 1277,
8489 /* 0 */ 1024, 820, 655, 526, 423,
8490 /* 5 */ 335, 272, 215, 172, 137,
8491 /* 10 */ 110, 87, 70, 56, 45,
8492 /* 15 */ 36, 29, 23, 18, 15,
8493};
8494
8495/*
8496 * Inverse (2^32/x) values of the sched_prio_to_weight[] array, precalculated.
8497 *
8498 * In cases where the weight does not change often, we can use the
8499 * precalculated inverse to speed up arithmetics by turning divisions
8500 * into multiplications:
8501 */
8502const u32 sched_prio_to_wmult[40] = {
8503 /* -20 */ 48388, 59856, 76040, 92818, 118348,
8504 /* -15 */ 147320, 184698, 229616, 287308, 360437,
8505 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
8506 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
8507 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
8508 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
8509 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
8510 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
8511};
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * kernel/sched/core.c
4 *
5 * Core kernel scheduler code and related syscalls
6 *
7 * Copyright (C) 1991-2002 Linus Torvalds
8 */
9#include "sched.h"
10
11#include <linux/nospec.h>
12
13#include <linux/kcov.h>
14
15#include <asm/switch_to.h>
16#include <asm/tlb.h>
17
18#include "../workqueue_internal.h"
19#include "../smpboot.h"
20
21#include "pelt.h"
22
23#define CREATE_TRACE_POINTS
24#include <trace/events/sched.h>
25
26/*
27 * Export tracepoints that act as a bare tracehook (ie: have no trace event
28 * associated with them) to allow external modules to probe them.
29 */
30EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_cfs_tp);
31EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_rt_tp);
32EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_dl_tp);
33EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_irq_tp);
34EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_se_tp);
35EXPORT_TRACEPOINT_SYMBOL_GPL(sched_overutilized_tp);
36
37DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
38
39#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_JUMP_LABEL)
40/*
41 * Debugging: various feature bits
42 *
43 * If SCHED_DEBUG is disabled, each compilation unit has its own copy of
44 * sysctl_sched_features, defined in sched.h, to allow constants propagation
45 * at compile time and compiler optimization based on features default.
46 */
47#define SCHED_FEAT(name, enabled) \
48 (1UL << __SCHED_FEAT_##name) * enabled |
49const_debug unsigned int sysctl_sched_features =
50#include "features.h"
51 0;
52#undef SCHED_FEAT
53#endif
54
55/*
56 * Number of tasks to iterate in a single balance run.
57 * Limited because this is done with IRQs disabled.
58 */
59const_debug unsigned int sysctl_sched_nr_migrate = 32;
60
61/*
62 * period over which we measure -rt task CPU usage in us.
63 * default: 1s
64 */
65unsigned int sysctl_sched_rt_period = 1000000;
66
67__read_mostly int scheduler_running;
68
69/*
70 * part of the period that we allow rt tasks to run in us.
71 * default: 0.95s
72 */
73int sysctl_sched_rt_runtime = 950000;
74
75/*
76 * __task_rq_lock - lock the rq @p resides on.
77 */
78struct rq *__task_rq_lock(struct task_struct *p, struct rq_flags *rf)
79 __acquires(rq->lock)
80{
81 struct rq *rq;
82
83 lockdep_assert_held(&p->pi_lock);
84
85 for (;;) {
86 rq = task_rq(p);
87 raw_spin_lock(&rq->lock);
88 if (likely(rq == task_rq(p) && !task_on_rq_migrating(p))) {
89 rq_pin_lock(rq, rf);
90 return rq;
91 }
92 raw_spin_unlock(&rq->lock);
93
94 while (unlikely(task_on_rq_migrating(p)))
95 cpu_relax();
96 }
97}
98
99/*
100 * task_rq_lock - lock p->pi_lock and lock the rq @p resides on.
101 */
102struct rq *task_rq_lock(struct task_struct *p, struct rq_flags *rf)
103 __acquires(p->pi_lock)
104 __acquires(rq->lock)
105{
106 struct rq *rq;
107
108 for (;;) {
109 raw_spin_lock_irqsave(&p->pi_lock, rf->flags);
110 rq = task_rq(p);
111 raw_spin_lock(&rq->lock);
112 /*
113 * move_queued_task() task_rq_lock()
114 *
115 * ACQUIRE (rq->lock)
116 * [S] ->on_rq = MIGRATING [L] rq = task_rq()
117 * WMB (__set_task_cpu()) ACQUIRE (rq->lock);
118 * [S] ->cpu = new_cpu [L] task_rq()
119 * [L] ->on_rq
120 * RELEASE (rq->lock)
121 *
122 * If we observe the old CPU in task_rq_lock(), the acquire of
123 * the old rq->lock will fully serialize against the stores.
124 *
125 * If we observe the new CPU in task_rq_lock(), the address
126 * dependency headed by '[L] rq = task_rq()' and the acquire
127 * will pair with the WMB to ensure we then also see migrating.
128 */
129 if (likely(rq == task_rq(p) && !task_on_rq_migrating(p))) {
130 rq_pin_lock(rq, rf);
131 return rq;
132 }
133 raw_spin_unlock(&rq->lock);
134 raw_spin_unlock_irqrestore(&p->pi_lock, rf->flags);
135
136 while (unlikely(task_on_rq_migrating(p)))
137 cpu_relax();
138 }
139}
140
141/*
142 * RQ-clock updating methods:
143 */
144
145static void update_rq_clock_task(struct rq *rq, s64 delta)
146{
147/*
148 * In theory, the compile should just see 0 here, and optimize out the call
149 * to sched_rt_avg_update. But I don't trust it...
150 */
151 s64 __maybe_unused steal = 0, irq_delta = 0;
152
153#ifdef CONFIG_IRQ_TIME_ACCOUNTING
154 irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time;
155
156 /*
157 * Since irq_time is only updated on {soft,}irq_exit, we might run into
158 * this case when a previous update_rq_clock() happened inside a
159 * {soft,}irq region.
160 *
161 * When this happens, we stop ->clock_task and only update the
162 * prev_irq_time stamp to account for the part that fit, so that a next
163 * update will consume the rest. This ensures ->clock_task is
164 * monotonic.
165 *
166 * It does however cause some slight miss-attribution of {soft,}irq
167 * time, a more accurate solution would be to update the irq_time using
168 * the current rq->clock timestamp, except that would require using
169 * atomic ops.
170 */
171 if (irq_delta > delta)
172 irq_delta = delta;
173
174 rq->prev_irq_time += irq_delta;
175 delta -= irq_delta;
176#endif
177#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
178 if (static_key_false((¶virt_steal_rq_enabled))) {
179 steal = paravirt_steal_clock(cpu_of(rq));
180 steal -= rq->prev_steal_time_rq;
181
182 if (unlikely(steal > delta))
183 steal = delta;
184
185 rq->prev_steal_time_rq += steal;
186 delta -= steal;
187 }
188#endif
189
190 rq->clock_task += delta;
191
192#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
193 if ((irq_delta + steal) && sched_feat(NONTASK_CAPACITY))
194 update_irq_load_avg(rq, irq_delta + steal);
195#endif
196 update_rq_clock_pelt(rq, delta);
197}
198
199void update_rq_clock(struct rq *rq)
200{
201 s64 delta;
202
203 lockdep_assert_held(&rq->lock);
204
205 if (rq->clock_update_flags & RQCF_ACT_SKIP)
206 return;
207
208#ifdef CONFIG_SCHED_DEBUG
209 if (sched_feat(WARN_DOUBLE_CLOCK))
210 SCHED_WARN_ON(rq->clock_update_flags & RQCF_UPDATED);
211 rq->clock_update_flags |= RQCF_UPDATED;
212#endif
213
214 delta = sched_clock_cpu(cpu_of(rq)) - rq->clock;
215 if (delta < 0)
216 return;
217 rq->clock += delta;
218 update_rq_clock_task(rq, delta);
219}
220
221
222#ifdef CONFIG_SCHED_HRTICK
223/*
224 * Use HR-timers to deliver accurate preemption points.
225 */
226
227static void hrtick_clear(struct rq *rq)
228{
229 if (hrtimer_active(&rq->hrtick_timer))
230 hrtimer_cancel(&rq->hrtick_timer);
231}
232
233/*
234 * High-resolution timer tick.
235 * Runs from hardirq context with interrupts disabled.
236 */
237static enum hrtimer_restart hrtick(struct hrtimer *timer)
238{
239 struct rq *rq = container_of(timer, struct rq, hrtick_timer);
240 struct rq_flags rf;
241
242 WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
243
244 rq_lock(rq, &rf);
245 update_rq_clock(rq);
246 rq->curr->sched_class->task_tick(rq, rq->curr, 1);
247 rq_unlock(rq, &rf);
248
249 return HRTIMER_NORESTART;
250}
251
252#ifdef CONFIG_SMP
253
254static void __hrtick_restart(struct rq *rq)
255{
256 struct hrtimer *timer = &rq->hrtick_timer;
257
258 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED_HARD);
259}
260
261/*
262 * called from hardirq (IPI) context
263 */
264static void __hrtick_start(void *arg)
265{
266 struct rq *rq = arg;
267 struct rq_flags rf;
268
269 rq_lock(rq, &rf);
270 __hrtick_restart(rq);
271 rq->hrtick_csd_pending = 0;
272 rq_unlock(rq, &rf);
273}
274
275/*
276 * Called to set the hrtick timer state.
277 *
278 * called with rq->lock held and irqs disabled
279 */
280void hrtick_start(struct rq *rq, u64 delay)
281{
282 struct hrtimer *timer = &rq->hrtick_timer;
283 ktime_t time;
284 s64 delta;
285
286 /*
287 * Don't schedule slices shorter than 10000ns, that just
288 * doesn't make sense and can cause timer DoS.
289 */
290 delta = max_t(s64, delay, 10000LL);
291 time = ktime_add_ns(timer->base->get_time(), delta);
292
293 hrtimer_set_expires(timer, time);
294
295 if (rq == this_rq()) {
296 __hrtick_restart(rq);
297 } else if (!rq->hrtick_csd_pending) {
298 smp_call_function_single_async(cpu_of(rq), &rq->hrtick_csd);
299 rq->hrtick_csd_pending = 1;
300 }
301}
302
303#else
304/*
305 * Called to set the hrtick timer state.
306 *
307 * called with rq->lock held and irqs disabled
308 */
309void hrtick_start(struct rq *rq, u64 delay)
310{
311 /*
312 * Don't schedule slices shorter than 10000ns, that just
313 * doesn't make sense. Rely on vruntime for fairness.
314 */
315 delay = max_t(u64, delay, 10000LL);
316 hrtimer_start(&rq->hrtick_timer, ns_to_ktime(delay),
317 HRTIMER_MODE_REL_PINNED_HARD);
318}
319#endif /* CONFIG_SMP */
320
321static void hrtick_rq_init(struct rq *rq)
322{
323#ifdef CONFIG_SMP
324 rq->hrtick_csd_pending = 0;
325
326 rq->hrtick_csd.flags = 0;
327 rq->hrtick_csd.func = __hrtick_start;
328 rq->hrtick_csd.info = rq;
329#endif
330
331 hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
332 rq->hrtick_timer.function = hrtick;
333}
334#else /* CONFIG_SCHED_HRTICK */
335static inline void hrtick_clear(struct rq *rq)
336{
337}
338
339static inline void hrtick_rq_init(struct rq *rq)
340{
341}
342#endif /* CONFIG_SCHED_HRTICK */
343
344/*
345 * cmpxchg based fetch_or, macro so it works for different integer types
346 */
347#define fetch_or(ptr, mask) \
348 ({ \
349 typeof(ptr) _ptr = (ptr); \
350 typeof(mask) _mask = (mask); \
351 typeof(*_ptr) _old, _val = *_ptr; \
352 \
353 for (;;) { \
354 _old = cmpxchg(_ptr, _val, _val | _mask); \
355 if (_old == _val) \
356 break; \
357 _val = _old; \
358 } \
359 _old; \
360})
361
362#if defined(CONFIG_SMP) && defined(TIF_POLLING_NRFLAG)
363/*
364 * Atomically set TIF_NEED_RESCHED and test for TIF_POLLING_NRFLAG,
365 * this avoids any races wrt polling state changes and thereby avoids
366 * spurious IPIs.
367 */
368static bool set_nr_and_not_polling(struct task_struct *p)
369{
370 struct thread_info *ti = task_thread_info(p);
371 return !(fetch_or(&ti->flags, _TIF_NEED_RESCHED) & _TIF_POLLING_NRFLAG);
372}
373
374/*
375 * Atomically set TIF_NEED_RESCHED if TIF_POLLING_NRFLAG is set.
376 *
377 * If this returns true, then the idle task promises to call
378 * sched_ttwu_pending() and reschedule soon.
379 */
380static bool set_nr_if_polling(struct task_struct *p)
381{
382 struct thread_info *ti = task_thread_info(p);
383 typeof(ti->flags) old, val = READ_ONCE(ti->flags);
384
385 for (;;) {
386 if (!(val & _TIF_POLLING_NRFLAG))
387 return false;
388 if (val & _TIF_NEED_RESCHED)
389 return true;
390 old = cmpxchg(&ti->flags, val, val | _TIF_NEED_RESCHED);
391 if (old == val)
392 break;
393 val = old;
394 }
395 return true;
396}
397
398#else
399static bool set_nr_and_not_polling(struct task_struct *p)
400{
401 set_tsk_need_resched(p);
402 return true;
403}
404
405#ifdef CONFIG_SMP
406static bool set_nr_if_polling(struct task_struct *p)
407{
408 return false;
409}
410#endif
411#endif
412
413static bool __wake_q_add(struct wake_q_head *head, struct task_struct *task)
414{
415 struct wake_q_node *node = &task->wake_q;
416
417 /*
418 * Atomically grab the task, if ->wake_q is !nil already it means
419 * its already queued (either by us or someone else) and will get the
420 * wakeup due to that.
421 *
422 * In order to ensure that a pending wakeup will observe our pending
423 * state, even in the failed case, an explicit smp_mb() must be used.
424 */
425 smp_mb__before_atomic();
426 if (unlikely(cmpxchg_relaxed(&node->next, NULL, WAKE_Q_TAIL)))
427 return false;
428
429 /*
430 * The head is context local, there can be no concurrency.
431 */
432 *head->lastp = node;
433 head->lastp = &node->next;
434 return true;
435}
436
437/**
438 * wake_q_add() - queue a wakeup for 'later' waking.
439 * @head: the wake_q_head to add @task to
440 * @task: the task to queue for 'later' wakeup
441 *
442 * Queue a task for later wakeup, most likely by the wake_up_q() call in the
443 * same context, _HOWEVER_ this is not guaranteed, the wakeup can come
444 * instantly.
445 *
446 * This function must be used as-if it were wake_up_process(); IOW the task
447 * must be ready to be woken at this location.
448 */
449void wake_q_add(struct wake_q_head *head, struct task_struct *task)
450{
451 if (__wake_q_add(head, task))
452 get_task_struct(task);
453}
454
455/**
456 * wake_q_add_safe() - safely queue a wakeup for 'later' waking.
457 * @head: the wake_q_head to add @task to
458 * @task: the task to queue for 'later' wakeup
459 *
460 * Queue a task for later wakeup, most likely by the wake_up_q() call in the
461 * same context, _HOWEVER_ this is not guaranteed, the wakeup can come
462 * instantly.
463 *
464 * This function must be used as-if it were wake_up_process(); IOW the task
465 * must be ready to be woken at this location.
466 *
467 * This function is essentially a task-safe equivalent to wake_q_add(). Callers
468 * that already hold reference to @task can call the 'safe' version and trust
469 * wake_q to do the right thing depending whether or not the @task is already
470 * queued for wakeup.
471 */
472void wake_q_add_safe(struct wake_q_head *head, struct task_struct *task)
473{
474 if (!__wake_q_add(head, task))
475 put_task_struct(task);
476}
477
478void wake_up_q(struct wake_q_head *head)
479{
480 struct wake_q_node *node = head->first;
481
482 while (node != WAKE_Q_TAIL) {
483 struct task_struct *task;
484
485 task = container_of(node, struct task_struct, wake_q);
486 BUG_ON(!task);
487 /* Task can safely be re-inserted now: */
488 node = node->next;
489 task->wake_q.next = NULL;
490
491 /*
492 * wake_up_process() executes a full barrier, which pairs with
493 * the queueing in wake_q_add() so as not to miss wakeups.
494 */
495 wake_up_process(task);
496 put_task_struct(task);
497 }
498}
499
500/*
501 * resched_curr - mark rq's current task 'to be rescheduled now'.
502 *
503 * On UP this means the setting of the need_resched flag, on SMP it
504 * might also involve a cross-CPU call to trigger the scheduler on
505 * the target CPU.
506 */
507void resched_curr(struct rq *rq)
508{
509 struct task_struct *curr = rq->curr;
510 int cpu;
511
512 lockdep_assert_held(&rq->lock);
513
514 if (test_tsk_need_resched(curr))
515 return;
516
517 cpu = cpu_of(rq);
518
519 if (cpu == smp_processor_id()) {
520 set_tsk_need_resched(curr);
521 set_preempt_need_resched();
522 return;
523 }
524
525 if (set_nr_and_not_polling(curr))
526 smp_send_reschedule(cpu);
527 else
528 trace_sched_wake_idle_without_ipi(cpu);
529}
530
531void resched_cpu(int cpu)
532{
533 struct rq *rq = cpu_rq(cpu);
534 unsigned long flags;
535
536 raw_spin_lock_irqsave(&rq->lock, flags);
537 if (cpu_online(cpu) || cpu == smp_processor_id())
538 resched_curr(rq);
539 raw_spin_unlock_irqrestore(&rq->lock, flags);
540}
541
542#ifdef CONFIG_SMP
543#ifdef CONFIG_NO_HZ_COMMON
544/*
545 * In the semi idle case, use the nearest busy CPU for migrating timers
546 * from an idle CPU. This is good for power-savings.
547 *
548 * We don't do similar optimization for completely idle system, as
549 * selecting an idle CPU will add more delays to the timers than intended
550 * (as that CPU's timer base may not be uptodate wrt jiffies etc).
551 */
552int get_nohz_timer_target(void)
553{
554 int i, cpu = smp_processor_id();
555 struct sched_domain *sd;
556
557 if (!idle_cpu(cpu) && housekeeping_cpu(cpu, HK_FLAG_TIMER))
558 return cpu;
559
560 rcu_read_lock();
561 for_each_domain(cpu, sd) {
562 for_each_cpu(i, sched_domain_span(sd)) {
563 if (cpu == i)
564 continue;
565
566 if (!idle_cpu(i) && housekeeping_cpu(i, HK_FLAG_TIMER)) {
567 cpu = i;
568 goto unlock;
569 }
570 }
571 }
572
573 if (!housekeeping_cpu(cpu, HK_FLAG_TIMER))
574 cpu = housekeeping_any_cpu(HK_FLAG_TIMER);
575unlock:
576 rcu_read_unlock();
577 return cpu;
578}
579
580/*
581 * When add_timer_on() enqueues a timer into the timer wheel of an
582 * idle CPU then this timer might expire before the next timer event
583 * which is scheduled to wake up that CPU. In case of a completely
584 * idle system the next event might even be infinite time into the
585 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
586 * leaves the inner idle loop so the newly added timer is taken into
587 * account when the CPU goes back to idle and evaluates the timer
588 * wheel for the next timer event.
589 */
590static void wake_up_idle_cpu(int cpu)
591{
592 struct rq *rq = cpu_rq(cpu);
593
594 if (cpu == smp_processor_id())
595 return;
596
597 if (set_nr_and_not_polling(rq->idle))
598 smp_send_reschedule(cpu);
599 else
600 trace_sched_wake_idle_without_ipi(cpu);
601}
602
603static bool wake_up_full_nohz_cpu(int cpu)
604{
605 /*
606 * We just need the target to call irq_exit() and re-evaluate
607 * the next tick. The nohz full kick at least implies that.
608 * If needed we can still optimize that later with an
609 * empty IRQ.
610 */
611 if (cpu_is_offline(cpu))
612 return true; /* Don't try to wake offline CPUs. */
613 if (tick_nohz_full_cpu(cpu)) {
614 if (cpu != smp_processor_id() ||
615 tick_nohz_tick_stopped())
616 tick_nohz_full_kick_cpu(cpu);
617 return true;
618 }
619
620 return false;
621}
622
623/*
624 * Wake up the specified CPU. If the CPU is going offline, it is the
625 * caller's responsibility to deal with the lost wakeup, for example,
626 * by hooking into the CPU_DEAD notifier like timers and hrtimers do.
627 */
628void wake_up_nohz_cpu(int cpu)
629{
630 if (!wake_up_full_nohz_cpu(cpu))
631 wake_up_idle_cpu(cpu);
632}
633
634static inline bool got_nohz_idle_kick(void)
635{
636 int cpu = smp_processor_id();
637
638 if (!(atomic_read(nohz_flags(cpu)) & NOHZ_KICK_MASK))
639 return false;
640
641 if (idle_cpu(cpu) && !need_resched())
642 return true;
643
644 /*
645 * We can't run Idle Load Balance on this CPU for this time so we
646 * cancel it and clear NOHZ_BALANCE_KICK
647 */
648 atomic_andnot(NOHZ_KICK_MASK, nohz_flags(cpu));
649 return false;
650}
651
652#else /* CONFIG_NO_HZ_COMMON */
653
654static inline bool got_nohz_idle_kick(void)
655{
656 return false;
657}
658
659#endif /* CONFIG_NO_HZ_COMMON */
660
661#ifdef CONFIG_NO_HZ_FULL
662bool sched_can_stop_tick(struct rq *rq)
663{
664 int fifo_nr_running;
665
666 /* Deadline tasks, even if single, need the tick */
667 if (rq->dl.dl_nr_running)
668 return false;
669
670 /*
671 * If there are more than one RR tasks, we need the tick to effect the
672 * actual RR behaviour.
673 */
674 if (rq->rt.rr_nr_running) {
675 if (rq->rt.rr_nr_running == 1)
676 return true;
677 else
678 return false;
679 }
680
681 /*
682 * If there's no RR tasks, but FIFO tasks, we can skip the tick, no
683 * forced preemption between FIFO tasks.
684 */
685 fifo_nr_running = rq->rt.rt_nr_running - rq->rt.rr_nr_running;
686 if (fifo_nr_running)
687 return true;
688
689 /*
690 * If there are no DL,RR/FIFO tasks, there must only be CFS tasks left;
691 * if there's more than one we need the tick for involuntary
692 * preemption.
693 */
694 if (rq->nr_running > 1)
695 return false;
696
697 return true;
698}
699#endif /* CONFIG_NO_HZ_FULL */
700#endif /* CONFIG_SMP */
701
702#if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \
703 (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH)))
704/*
705 * Iterate task_group tree rooted at *from, calling @down when first entering a
706 * node and @up when leaving it for the final time.
707 *
708 * Caller must hold rcu_lock or sufficient equivalent.
709 */
710int walk_tg_tree_from(struct task_group *from,
711 tg_visitor down, tg_visitor up, void *data)
712{
713 struct task_group *parent, *child;
714 int ret;
715
716 parent = from;
717
718down:
719 ret = (*down)(parent, data);
720 if (ret)
721 goto out;
722 list_for_each_entry_rcu(child, &parent->children, siblings) {
723 parent = child;
724 goto down;
725
726up:
727 continue;
728 }
729 ret = (*up)(parent, data);
730 if (ret || parent == from)
731 goto out;
732
733 child = parent;
734 parent = parent->parent;
735 if (parent)
736 goto up;
737out:
738 return ret;
739}
740
741int tg_nop(struct task_group *tg, void *data)
742{
743 return 0;
744}
745#endif
746
747static void set_load_weight(struct task_struct *p, bool update_load)
748{
749 int prio = p->static_prio - MAX_RT_PRIO;
750 struct load_weight *load = &p->se.load;
751
752 /*
753 * SCHED_IDLE tasks get minimal weight:
754 */
755 if (task_has_idle_policy(p)) {
756 load->weight = scale_load(WEIGHT_IDLEPRIO);
757 load->inv_weight = WMULT_IDLEPRIO;
758 p->se.runnable_weight = load->weight;
759 return;
760 }
761
762 /*
763 * SCHED_OTHER tasks have to update their load when changing their
764 * weight
765 */
766 if (update_load && p->sched_class == &fair_sched_class) {
767 reweight_task(p, prio);
768 } else {
769 load->weight = scale_load(sched_prio_to_weight[prio]);
770 load->inv_weight = sched_prio_to_wmult[prio];
771 p->se.runnable_weight = load->weight;
772 }
773}
774
775#ifdef CONFIG_UCLAMP_TASK
776/*
777 * Serializes updates of utilization clamp values
778 *
779 * The (slow-path) user-space triggers utilization clamp value updates which
780 * can require updates on (fast-path) scheduler's data structures used to
781 * support enqueue/dequeue operations.
782 * While the per-CPU rq lock protects fast-path update operations, user-space
783 * requests are serialized using a mutex to reduce the risk of conflicting
784 * updates or API abuses.
785 */
786static DEFINE_MUTEX(uclamp_mutex);
787
788/* Max allowed minimum utilization */
789unsigned int sysctl_sched_uclamp_util_min = SCHED_CAPACITY_SCALE;
790
791/* Max allowed maximum utilization */
792unsigned int sysctl_sched_uclamp_util_max = SCHED_CAPACITY_SCALE;
793
794/* All clamps are required to be less or equal than these values */
795static struct uclamp_se uclamp_default[UCLAMP_CNT];
796
797/* Integer rounded range for each bucket */
798#define UCLAMP_BUCKET_DELTA DIV_ROUND_CLOSEST(SCHED_CAPACITY_SCALE, UCLAMP_BUCKETS)
799
800#define for_each_clamp_id(clamp_id) \
801 for ((clamp_id) = 0; (clamp_id) < UCLAMP_CNT; (clamp_id)++)
802
803static inline unsigned int uclamp_bucket_id(unsigned int clamp_value)
804{
805 return clamp_value / UCLAMP_BUCKET_DELTA;
806}
807
808static inline unsigned int uclamp_bucket_base_value(unsigned int clamp_value)
809{
810 return UCLAMP_BUCKET_DELTA * uclamp_bucket_id(clamp_value);
811}
812
813static inline enum uclamp_id uclamp_none(enum uclamp_id clamp_id)
814{
815 if (clamp_id == UCLAMP_MIN)
816 return 0;
817 return SCHED_CAPACITY_SCALE;
818}
819
820static inline void uclamp_se_set(struct uclamp_se *uc_se,
821 unsigned int value, bool user_defined)
822{
823 uc_se->value = value;
824 uc_se->bucket_id = uclamp_bucket_id(value);
825 uc_se->user_defined = user_defined;
826}
827
828static inline unsigned int
829uclamp_idle_value(struct rq *rq, enum uclamp_id clamp_id,
830 unsigned int clamp_value)
831{
832 /*
833 * Avoid blocked utilization pushing up the frequency when we go
834 * idle (which drops the max-clamp) by retaining the last known
835 * max-clamp.
836 */
837 if (clamp_id == UCLAMP_MAX) {
838 rq->uclamp_flags |= UCLAMP_FLAG_IDLE;
839 return clamp_value;
840 }
841
842 return uclamp_none(UCLAMP_MIN);
843}
844
845static inline void uclamp_idle_reset(struct rq *rq, enum uclamp_id clamp_id,
846 unsigned int clamp_value)
847{
848 /* Reset max-clamp retention only on idle exit */
849 if (!(rq->uclamp_flags & UCLAMP_FLAG_IDLE))
850 return;
851
852 WRITE_ONCE(rq->uclamp[clamp_id].value, clamp_value);
853}
854
855static inline
856enum uclamp_id uclamp_rq_max_value(struct rq *rq, enum uclamp_id clamp_id,
857 unsigned int clamp_value)
858{
859 struct uclamp_bucket *bucket = rq->uclamp[clamp_id].bucket;
860 int bucket_id = UCLAMP_BUCKETS - 1;
861
862 /*
863 * Since both min and max clamps are max aggregated, find the
864 * top most bucket with tasks in.
865 */
866 for ( ; bucket_id >= 0; bucket_id--) {
867 if (!bucket[bucket_id].tasks)
868 continue;
869 return bucket[bucket_id].value;
870 }
871
872 /* No tasks -- default clamp values */
873 return uclamp_idle_value(rq, clamp_id, clamp_value);
874}
875
876static inline struct uclamp_se
877uclamp_tg_restrict(struct task_struct *p, enum uclamp_id clamp_id)
878{
879 struct uclamp_se uc_req = p->uclamp_req[clamp_id];
880#ifdef CONFIG_UCLAMP_TASK_GROUP
881 struct uclamp_se uc_max;
882
883 /*
884 * Tasks in autogroups or root task group will be
885 * restricted by system defaults.
886 */
887 if (task_group_is_autogroup(task_group(p)))
888 return uc_req;
889 if (task_group(p) == &root_task_group)
890 return uc_req;
891
892 uc_max = task_group(p)->uclamp[clamp_id];
893 if (uc_req.value > uc_max.value || !uc_req.user_defined)
894 return uc_max;
895#endif
896
897 return uc_req;
898}
899
900/*
901 * The effective clamp bucket index of a task depends on, by increasing
902 * priority:
903 * - the task specific clamp value, when explicitly requested from userspace
904 * - the task group effective clamp value, for tasks not either in the root
905 * group or in an autogroup
906 * - the system default clamp value, defined by the sysadmin
907 */
908static inline struct uclamp_se
909uclamp_eff_get(struct task_struct *p, enum uclamp_id clamp_id)
910{
911 struct uclamp_se uc_req = uclamp_tg_restrict(p, clamp_id);
912 struct uclamp_se uc_max = uclamp_default[clamp_id];
913
914 /* System default restrictions always apply */
915 if (unlikely(uc_req.value > uc_max.value))
916 return uc_max;
917
918 return uc_req;
919}
920
921enum uclamp_id uclamp_eff_value(struct task_struct *p, enum uclamp_id clamp_id)
922{
923 struct uclamp_se uc_eff;
924
925 /* Task currently refcounted: use back-annotated (effective) value */
926 if (p->uclamp[clamp_id].active)
927 return p->uclamp[clamp_id].value;
928
929 uc_eff = uclamp_eff_get(p, clamp_id);
930
931 return uc_eff.value;
932}
933
934/*
935 * When a task is enqueued on a rq, the clamp bucket currently defined by the
936 * task's uclamp::bucket_id is refcounted on that rq. This also immediately
937 * updates the rq's clamp value if required.
938 *
939 * Tasks can have a task-specific value requested from user-space, track
940 * within each bucket the maximum value for tasks refcounted in it.
941 * This "local max aggregation" allows to track the exact "requested" value
942 * for each bucket when all its RUNNABLE tasks require the same clamp.
943 */
944static inline void uclamp_rq_inc_id(struct rq *rq, struct task_struct *p,
945 enum uclamp_id clamp_id)
946{
947 struct uclamp_rq *uc_rq = &rq->uclamp[clamp_id];
948 struct uclamp_se *uc_se = &p->uclamp[clamp_id];
949 struct uclamp_bucket *bucket;
950
951 lockdep_assert_held(&rq->lock);
952
953 /* Update task effective clamp */
954 p->uclamp[clamp_id] = uclamp_eff_get(p, clamp_id);
955
956 bucket = &uc_rq->bucket[uc_se->bucket_id];
957 bucket->tasks++;
958 uc_se->active = true;
959
960 uclamp_idle_reset(rq, clamp_id, uc_se->value);
961
962 /*
963 * Local max aggregation: rq buckets always track the max
964 * "requested" clamp value of its RUNNABLE tasks.
965 */
966 if (bucket->tasks == 1 || uc_se->value > bucket->value)
967 bucket->value = uc_se->value;
968
969 if (uc_se->value > READ_ONCE(uc_rq->value))
970 WRITE_ONCE(uc_rq->value, uc_se->value);
971}
972
973/*
974 * When a task is dequeued from a rq, the clamp bucket refcounted by the task
975 * is released. If this is the last task reference counting the rq's max
976 * active clamp value, then the rq's clamp value is updated.
977 *
978 * Both refcounted tasks and rq's cached clamp values are expected to be
979 * always valid. If it's detected they are not, as defensive programming,
980 * enforce the expected state and warn.
981 */
982static inline void uclamp_rq_dec_id(struct rq *rq, struct task_struct *p,
983 enum uclamp_id clamp_id)
984{
985 struct uclamp_rq *uc_rq = &rq->uclamp[clamp_id];
986 struct uclamp_se *uc_se = &p->uclamp[clamp_id];
987 struct uclamp_bucket *bucket;
988 unsigned int bkt_clamp;
989 unsigned int rq_clamp;
990
991 lockdep_assert_held(&rq->lock);
992
993 bucket = &uc_rq->bucket[uc_se->bucket_id];
994 SCHED_WARN_ON(!bucket->tasks);
995 if (likely(bucket->tasks))
996 bucket->tasks--;
997 uc_se->active = false;
998
999 /*
1000 * Keep "local max aggregation" simple and accept to (possibly)
1001 * overboost some RUNNABLE tasks in the same bucket.
1002 * The rq clamp bucket value is reset to its base value whenever
1003 * there are no more RUNNABLE tasks refcounting it.
1004 */
1005 if (likely(bucket->tasks))
1006 return;
1007
1008 rq_clamp = READ_ONCE(uc_rq->value);
1009 /*
1010 * Defensive programming: this should never happen. If it happens,
1011 * e.g. due to future modification, warn and fixup the expected value.
1012 */
1013 SCHED_WARN_ON(bucket->value > rq_clamp);
1014 if (bucket->value >= rq_clamp) {
1015 bkt_clamp = uclamp_rq_max_value(rq, clamp_id, uc_se->value);
1016 WRITE_ONCE(uc_rq->value, bkt_clamp);
1017 }
1018}
1019
1020static inline void uclamp_rq_inc(struct rq *rq, struct task_struct *p)
1021{
1022 enum uclamp_id clamp_id;
1023
1024 if (unlikely(!p->sched_class->uclamp_enabled))
1025 return;
1026
1027 for_each_clamp_id(clamp_id)
1028 uclamp_rq_inc_id(rq, p, clamp_id);
1029
1030 /* Reset clamp idle holding when there is one RUNNABLE task */
1031 if (rq->uclamp_flags & UCLAMP_FLAG_IDLE)
1032 rq->uclamp_flags &= ~UCLAMP_FLAG_IDLE;
1033}
1034
1035static inline void uclamp_rq_dec(struct rq *rq, struct task_struct *p)
1036{
1037 enum uclamp_id clamp_id;
1038
1039 if (unlikely(!p->sched_class->uclamp_enabled))
1040 return;
1041
1042 for_each_clamp_id(clamp_id)
1043 uclamp_rq_dec_id(rq, p, clamp_id);
1044}
1045
1046static inline void
1047uclamp_update_active(struct task_struct *p, enum uclamp_id clamp_id)
1048{
1049 struct rq_flags rf;
1050 struct rq *rq;
1051
1052 /*
1053 * Lock the task and the rq where the task is (or was) queued.
1054 *
1055 * We might lock the (previous) rq of a !RUNNABLE task, but that's the
1056 * price to pay to safely serialize util_{min,max} updates with
1057 * enqueues, dequeues and migration operations.
1058 * This is the same locking schema used by __set_cpus_allowed_ptr().
1059 */
1060 rq = task_rq_lock(p, &rf);
1061
1062 /*
1063 * Setting the clamp bucket is serialized by task_rq_lock().
1064 * If the task is not yet RUNNABLE and its task_struct is not
1065 * affecting a valid clamp bucket, the next time it's enqueued,
1066 * it will already see the updated clamp bucket value.
1067 */
1068 if (p->uclamp[clamp_id].active) {
1069 uclamp_rq_dec_id(rq, p, clamp_id);
1070 uclamp_rq_inc_id(rq, p, clamp_id);
1071 }
1072
1073 task_rq_unlock(rq, p, &rf);
1074}
1075
1076#ifdef CONFIG_UCLAMP_TASK_GROUP
1077static inline void
1078uclamp_update_active_tasks(struct cgroup_subsys_state *css,
1079 unsigned int clamps)
1080{
1081 enum uclamp_id clamp_id;
1082 struct css_task_iter it;
1083 struct task_struct *p;
1084
1085 css_task_iter_start(css, 0, &it);
1086 while ((p = css_task_iter_next(&it))) {
1087 for_each_clamp_id(clamp_id) {
1088 if ((0x1 << clamp_id) & clamps)
1089 uclamp_update_active(p, clamp_id);
1090 }
1091 }
1092 css_task_iter_end(&it);
1093}
1094
1095static void cpu_util_update_eff(struct cgroup_subsys_state *css);
1096static void uclamp_update_root_tg(void)
1097{
1098 struct task_group *tg = &root_task_group;
1099
1100 uclamp_se_set(&tg->uclamp_req[UCLAMP_MIN],
1101 sysctl_sched_uclamp_util_min, false);
1102 uclamp_se_set(&tg->uclamp_req[UCLAMP_MAX],
1103 sysctl_sched_uclamp_util_max, false);
1104
1105 rcu_read_lock();
1106 cpu_util_update_eff(&root_task_group.css);
1107 rcu_read_unlock();
1108}
1109#else
1110static void uclamp_update_root_tg(void) { }
1111#endif
1112
1113int sysctl_sched_uclamp_handler(struct ctl_table *table, int write,
1114 void __user *buffer, size_t *lenp,
1115 loff_t *ppos)
1116{
1117 bool update_root_tg = false;
1118 int old_min, old_max;
1119 int result;
1120
1121 mutex_lock(&uclamp_mutex);
1122 old_min = sysctl_sched_uclamp_util_min;
1123 old_max = sysctl_sched_uclamp_util_max;
1124
1125 result = proc_dointvec(table, write, buffer, lenp, ppos);
1126 if (result)
1127 goto undo;
1128 if (!write)
1129 goto done;
1130
1131 if (sysctl_sched_uclamp_util_min > sysctl_sched_uclamp_util_max ||
1132 sysctl_sched_uclamp_util_max > SCHED_CAPACITY_SCALE) {
1133 result = -EINVAL;
1134 goto undo;
1135 }
1136
1137 if (old_min != sysctl_sched_uclamp_util_min) {
1138 uclamp_se_set(&uclamp_default[UCLAMP_MIN],
1139 sysctl_sched_uclamp_util_min, false);
1140 update_root_tg = true;
1141 }
1142 if (old_max != sysctl_sched_uclamp_util_max) {
1143 uclamp_se_set(&uclamp_default[UCLAMP_MAX],
1144 sysctl_sched_uclamp_util_max, false);
1145 update_root_tg = true;
1146 }
1147
1148 if (update_root_tg)
1149 uclamp_update_root_tg();
1150
1151 /*
1152 * We update all RUNNABLE tasks only when task groups are in use.
1153 * Otherwise, keep it simple and do just a lazy update at each next
1154 * task enqueue time.
1155 */
1156
1157 goto done;
1158
1159undo:
1160 sysctl_sched_uclamp_util_min = old_min;
1161 sysctl_sched_uclamp_util_max = old_max;
1162done:
1163 mutex_unlock(&uclamp_mutex);
1164
1165 return result;
1166}
1167
1168static int uclamp_validate(struct task_struct *p,
1169 const struct sched_attr *attr)
1170{
1171 unsigned int lower_bound = p->uclamp_req[UCLAMP_MIN].value;
1172 unsigned int upper_bound = p->uclamp_req[UCLAMP_MAX].value;
1173
1174 if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MIN)
1175 lower_bound = attr->sched_util_min;
1176 if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MAX)
1177 upper_bound = attr->sched_util_max;
1178
1179 if (lower_bound > upper_bound)
1180 return -EINVAL;
1181 if (upper_bound > SCHED_CAPACITY_SCALE)
1182 return -EINVAL;
1183
1184 return 0;
1185}
1186
1187static void __setscheduler_uclamp(struct task_struct *p,
1188 const struct sched_attr *attr)
1189{
1190 enum uclamp_id clamp_id;
1191
1192 /*
1193 * On scheduling class change, reset to default clamps for tasks
1194 * without a task-specific value.
1195 */
1196 for_each_clamp_id(clamp_id) {
1197 struct uclamp_se *uc_se = &p->uclamp_req[clamp_id];
1198 unsigned int clamp_value = uclamp_none(clamp_id);
1199
1200 /* Keep using defined clamps across class changes */
1201 if (uc_se->user_defined)
1202 continue;
1203
1204 /* By default, RT tasks always get 100% boost */
1205 if (unlikely(rt_task(p) && clamp_id == UCLAMP_MIN))
1206 clamp_value = uclamp_none(UCLAMP_MAX);
1207
1208 uclamp_se_set(uc_se, clamp_value, false);
1209 }
1210
1211 if (likely(!(attr->sched_flags & SCHED_FLAG_UTIL_CLAMP)))
1212 return;
1213
1214 if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MIN) {
1215 uclamp_se_set(&p->uclamp_req[UCLAMP_MIN],
1216 attr->sched_util_min, true);
1217 }
1218
1219 if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MAX) {
1220 uclamp_se_set(&p->uclamp_req[UCLAMP_MAX],
1221 attr->sched_util_max, true);
1222 }
1223}
1224
1225static void uclamp_fork(struct task_struct *p)
1226{
1227 enum uclamp_id clamp_id;
1228
1229 for_each_clamp_id(clamp_id)
1230 p->uclamp[clamp_id].active = false;
1231
1232 if (likely(!p->sched_reset_on_fork))
1233 return;
1234
1235 for_each_clamp_id(clamp_id) {
1236 unsigned int clamp_value = uclamp_none(clamp_id);
1237
1238 /* By default, RT tasks always get 100% boost */
1239 if (unlikely(rt_task(p) && clamp_id == UCLAMP_MIN))
1240 clamp_value = uclamp_none(UCLAMP_MAX);
1241
1242 uclamp_se_set(&p->uclamp_req[clamp_id], clamp_value, false);
1243 }
1244}
1245
1246static void __init init_uclamp(void)
1247{
1248 struct uclamp_se uc_max = {};
1249 enum uclamp_id clamp_id;
1250 int cpu;
1251
1252 mutex_init(&uclamp_mutex);
1253
1254 for_each_possible_cpu(cpu) {
1255 memset(&cpu_rq(cpu)->uclamp, 0, sizeof(struct uclamp_rq));
1256 cpu_rq(cpu)->uclamp_flags = 0;
1257 }
1258
1259 for_each_clamp_id(clamp_id) {
1260 uclamp_se_set(&init_task.uclamp_req[clamp_id],
1261 uclamp_none(clamp_id), false);
1262 }
1263
1264 /* System defaults allow max clamp values for both indexes */
1265 uclamp_se_set(&uc_max, uclamp_none(UCLAMP_MAX), false);
1266 for_each_clamp_id(clamp_id) {
1267 uclamp_default[clamp_id] = uc_max;
1268#ifdef CONFIG_UCLAMP_TASK_GROUP
1269 root_task_group.uclamp_req[clamp_id] = uc_max;
1270 root_task_group.uclamp[clamp_id] = uc_max;
1271#endif
1272 }
1273}
1274
1275#else /* CONFIG_UCLAMP_TASK */
1276static inline void uclamp_rq_inc(struct rq *rq, struct task_struct *p) { }
1277static inline void uclamp_rq_dec(struct rq *rq, struct task_struct *p) { }
1278static inline int uclamp_validate(struct task_struct *p,
1279 const struct sched_attr *attr)
1280{
1281 return -EOPNOTSUPP;
1282}
1283static void __setscheduler_uclamp(struct task_struct *p,
1284 const struct sched_attr *attr) { }
1285static inline void uclamp_fork(struct task_struct *p) { }
1286static inline void init_uclamp(void) { }
1287#endif /* CONFIG_UCLAMP_TASK */
1288
1289static inline void enqueue_task(struct rq *rq, struct task_struct *p, int flags)
1290{
1291 if (!(flags & ENQUEUE_NOCLOCK))
1292 update_rq_clock(rq);
1293
1294 if (!(flags & ENQUEUE_RESTORE)) {
1295 sched_info_queued(rq, p);
1296 psi_enqueue(p, flags & ENQUEUE_WAKEUP);
1297 }
1298
1299 uclamp_rq_inc(rq, p);
1300 p->sched_class->enqueue_task(rq, p, flags);
1301}
1302
1303static inline void dequeue_task(struct rq *rq, struct task_struct *p, int flags)
1304{
1305 if (!(flags & DEQUEUE_NOCLOCK))
1306 update_rq_clock(rq);
1307
1308 if (!(flags & DEQUEUE_SAVE)) {
1309 sched_info_dequeued(rq, p);
1310 psi_dequeue(p, flags & DEQUEUE_SLEEP);
1311 }
1312
1313 uclamp_rq_dec(rq, p);
1314 p->sched_class->dequeue_task(rq, p, flags);
1315}
1316
1317void activate_task(struct rq *rq, struct task_struct *p, int flags)
1318{
1319 if (task_contributes_to_load(p))
1320 rq->nr_uninterruptible--;
1321
1322 enqueue_task(rq, p, flags);
1323
1324 p->on_rq = TASK_ON_RQ_QUEUED;
1325}
1326
1327void deactivate_task(struct rq *rq, struct task_struct *p, int flags)
1328{
1329 p->on_rq = (flags & DEQUEUE_SLEEP) ? 0 : TASK_ON_RQ_MIGRATING;
1330
1331 if (task_contributes_to_load(p))
1332 rq->nr_uninterruptible++;
1333
1334 dequeue_task(rq, p, flags);
1335}
1336
1337/*
1338 * __normal_prio - return the priority that is based on the static prio
1339 */
1340static inline int __normal_prio(struct task_struct *p)
1341{
1342 return p->static_prio;
1343}
1344
1345/*
1346 * Calculate the expected normal priority: i.e. priority
1347 * without taking RT-inheritance into account. Might be
1348 * boosted by interactivity modifiers. Changes upon fork,
1349 * setprio syscalls, and whenever the interactivity
1350 * estimator recalculates.
1351 */
1352static inline int normal_prio(struct task_struct *p)
1353{
1354 int prio;
1355
1356 if (task_has_dl_policy(p))
1357 prio = MAX_DL_PRIO-1;
1358 else if (task_has_rt_policy(p))
1359 prio = MAX_RT_PRIO-1 - p->rt_priority;
1360 else
1361 prio = __normal_prio(p);
1362 return prio;
1363}
1364
1365/*
1366 * Calculate the current priority, i.e. the priority
1367 * taken into account by the scheduler. This value might
1368 * be boosted by RT tasks, or might be boosted by
1369 * interactivity modifiers. Will be RT if the task got
1370 * RT-boosted. If not then it returns p->normal_prio.
1371 */
1372static int effective_prio(struct task_struct *p)
1373{
1374 p->normal_prio = normal_prio(p);
1375 /*
1376 * If we are RT tasks or we were boosted to RT priority,
1377 * keep the priority unchanged. Otherwise, update priority
1378 * to the normal priority:
1379 */
1380 if (!rt_prio(p->prio))
1381 return p->normal_prio;
1382 return p->prio;
1383}
1384
1385/**
1386 * task_curr - is this task currently executing on a CPU?
1387 * @p: the task in question.
1388 *
1389 * Return: 1 if the task is currently executing. 0 otherwise.
1390 */
1391inline int task_curr(const struct task_struct *p)
1392{
1393 return cpu_curr(task_cpu(p)) == p;
1394}
1395
1396/*
1397 * switched_from, switched_to and prio_changed must _NOT_ drop rq->lock,
1398 * use the balance_callback list if you want balancing.
1399 *
1400 * this means any call to check_class_changed() must be followed by a call to
1401 * balance_callback().
1402 */
1403static inline void check_class_changed(struct rq *rq, struct task_struct *p,
1404 const struct sched_class *prev_class,
1405 int oldprio)
1406{
1407 if (prev_class != p->sched_class) {
1408 if (prev_class->switched_from)
1409 prev_class->switched_from(rq, p);
1410
1411 p->sched_class->switched_to(rq, p);
1412 } else if (oldprio != p->prio || dl_task(p))
1413 p->sched_class->prio_changed(rq, p, oldprio);
1414}
1415
1416void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags)
1417{
1418 const struct sched_class *class;
1419
1420 if (p->sched_class == rq->curr->sched_class) {
1421 rq->curr->sched_class->check_preempt_curr(rq, p, flags);
1422 } else {
1423 for_each_class(class) {
1424 if (class == rq->curr->sched_class)
1425 break;
1426 if (class == p->sched_class) {
1427 resched_curr(rq);
1428 break;
1429 }
1430 }
1431 }
1432
1433 /*
1434 * A queue event has occurred, and we're going to schedule. In
1435 * this case, we can save a useless back to back clock update.
1436 */
1437 if (task_on_rq_queued(rq->curr) && test_tsk_need_resched(rq->curr))
1438 rq_clock_skip_update(rq);
1439}
1440
1441#ifdef CONFIG_SMP
1442
1443static inline bool is_per_cpu_kthread(struct task_struct *p)
1444{
1445 if (!(p->flags & PF_KTHREAD))
1446 return false;
1447
1448 if (p->nr_cpus_allowed != 1)
1449 return false;
1450
1451 return true;
1452}
1453
1454/*
1455 * Per-CPU kthreads are allowed to run on !active && online CPUs, see
1456 * __set_cpus_allowed_ptr() and select_fallback_rq().
1457 */
1458static inline bool is_cpu_allowed(struct task_struct *p, int cpu)
1459{
1460 if (!cpumask_test_cpu(cpu, p->cpus_ptr))
1461 return false;
1462
1463 if (is_per_cpu_kthread(p))
1464 return cpu_online(cpu);
1465
1466 return cpu_active(cpu);
1467}
1468
1469/*
1470 * This is how migration works:
1471 *
1472 * 1) we invoke migration_cpu_stop() on the target CPU using
1473 * stop_one_cpu().
1474 * 2) stopper starts to run (implicitly forcing the migrated thread
1475 * off the CPU)
1476 * 3) it checks whether the migrated task is still in the wrong runqueue.
1477 * 4) if it's in the wrong runqueue then the migration thread removes
1478 * it and puts it into the right queue.
1479 * 5) stopper completes and stop_one_cpu() returns and the migration
1480 * is done.
1481 */
1482
1483/*
1484 * move_queued_task - move a queued task to new rq.
1485 *
1486 * Returns (locked) new rq. Old rq's lock is released.
1487 */
1488static struct rq *move_queued_task(struct rq *rq, struct rq_flags *rf,
1489 struct task_struct *p, int new_cpu)
1490{
1491 lockdep_assert_held(&rq->lock);
1492
1493 WRITE_ONCE(p->on_rq, TASK_ON_RQ_MIGRATING);
1494 dequeue_task(rq, p, DEQUEUE_NOCLOCK);
1495 set_task_cpu(p, new_cpu);
1496 rq_unlock(rq, rf);
1497
1498 rq = cpu_rq(new_cpu);
1499
1500 rq_lock(rq, rf);
1501 BUG_ON(task_cpu(p) != new_cpu);
1502 enqueue_task(rq, p, 0);
1503 p->on_rq = TASK_ON_RQ_QUEUED;
1504 check_preempt_curr(rq, p, 0);
1505
1506 return rq;
1507}
1508
1509struct migration_arg {
1510 struct task_struct *task;
1511 int dest_cpu;
1512};
1513
1514/*
1515 * Move (not current) task off this CPU, onto the destination CPU. We're doing
1516 * this because either it can't run here any more (set_cpus_allowed()
1517 * away from this CPU, or CPU going down), or because we're
1518 * attempting to rebalance this task on exec (sched_exec).
1519 *
1520 * So we race with normal scheduler movements, but that's OK, as long
1521 * as the task is no longer on this CPU.
1522 */
1523static struct rq *__migrate_task(struct rq *rq, struct rq_flags *rf,
1524 struct task_struct *p, int dest_cpu)
1525{
1526 /* Affinity changed (again). */
1527 if (!is_cpu_allowed(p, dest_cpu))
1528 return rq;
1529
1530 update_rq_clock(rq);
1531 rq = move_queued_task(rq, rf, p, dest_cpu);
1532
1533 return rq;
1534}
1535
1536/*
1537 * migration_cpu_stop - this will be executed by a highprio stopper thread
1538 * and performs thread migration by bumping thread off CPU then
1539 * 'pushing' onto another runqueue.
1540 */
1541static int migration_cpu_stop(void *data)
1542{
1543 struct migration_arg *arg = data;
1544 struct task_struct *p = arg->task;
1545 struct rq *rq = this_rq();
1546 struct rq_flags rf;
1547
1548 /*
1549 * The original target CPU might have gone down and we might
1550 * be on another CPU but it doesn't matter.
1551 */
1552 local_irq_disable();
1553 /*
1554 * We need to explicitly wake pending tasks before running
1555 * __migrate_task() such that we will not miss enforcing cpus_ptr
1556 * during wakeups, see set_cpus_allowed_ptr()'s TASK_WAKING test.
1557 */
1558 sched_ttwu_pending();
1559
1560 raw_spin_lock(&p->pi_lock);
1561 rq_lock(rq, &rf);
1562 /*
1563 * If task_rq(p) != rq, it cannot be migrated here, because we're
1564 * holding rq->lock, if p->on_rq == 0 it cannot get enqueued because
1565 * we're holding p->pi_lock.
1566 */
1567 if (task_rq(p) == rq) {
1568 if (task_on_rq_queued(p))
1569 rq = __migrate_task(rq, &rf, p, arg->dest_cpu);
1570 else
1571 p->wake_cpu = arg->dest_cpu;
1572 }
1573 rq_unlock(rq, &rf);
1574 raw_spin_unlock(&p->pi_lock);
1575
1576 local_irq_enable();
1577 return 0;
1578}
1579
1580/*
1581 * sched_class::set_cpus_allowed must do the below, but is not required to
1582 * actually call this function.
1583 */
1584void set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_mask)
1585{
1586 cpumask_copy(&p->cpus_mask, new_mask);
1587 p->nr_cpus_allowed = cpumask_weight(new_mask);
1588}
1589
1590void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
1591{
1592 struct rq *rq = task_rq(p);
1593 bool queued, running;
1594
1595 lockdep_assert_held(&p->pi_lock);
1596
1597 queued = task_on_rq_queued(p);
1598 running = task_current(rq, p);
1599
1600 if (queued) {
1601 /*
1602 * Because __kthread_bind() calls this on blocked tasks without
1603 * holding rq->lock.
1604 */
1605 lockdep_assert_held(&rq->lock);
1606 dequeue_task(rq, p, DEQUEUE_SAVE | DEQUEUE_NOCLOCK);
1607 }
1608 if (running)
1609 put_prev_task(rq, p);
1610
1611 p->sched_class->set_cpus_allowed(p, new_mask);
1612
1613 if (queued)
1614 enqueue_task(rq, p, ENQUEUE_RESTORE | ENQUEUE_NOCLOCK);
1615 if (running)
1616 set_next_task(rq, p);
1617}
1618
1619/*
1620 * Change a given task's CPU affinity. Migrate the thread to a
1621 * proper CPU and schedule it away if the CPU it's executing on
1622 * is removed from the allowed bitmask.
1623 *
1624 * NOTE: the caller must have a valid reference to the task, the
1625 * task must not exit() & deallocate itself prematurely. The
1626 * call is not atomic; no spinlocks may be held.
1627 */
1628static int __set_cpus_allowed_ptr(struct task_struct *p,
1629 const struct cpumask *new_mask, bool check)
1630{
1631 const struct cpumask *cpu_valid_mask = cpu_active_mask;
1632 unsigned int dest_cpu;
1633 struct rq_flags rf;
1634 struct rq *rq;
1635 int ret = 0;
1636
1637 rq = task_rq_lock(p, &rf);
1638 update_rq_clock(rq);
1639
1640 if (p->flags & PF_KTHREAD) {
1641 /*
1642 * Kernel threads are allowed on online && !active CPUs
1643 */
1644 cpu_valid_mask = cpu_online_mask;
1645 }
1646
1647 /*
1648 * Must re-check here, to close a race against __kthread_bind(),
1649 * sched_setaffinity() is not guaranteed to observe the flag.
1650 */
1651 if (check && (p->flags & PF_NO_SETAFFINITY)) {
1652 ret = -EINVAL;
1653 goto out;
1654 }
1655
1656 if (cpumask_equal(p->cpus_ptr, new_mask))
1657 goto out;
1658
1659 dest_cpu = cpumask_any_and(cpu_valid_mask, new_mask);
1660 if (dest_cpu >= nr_cpu_ids) {
1661 ret = -EINVAL;
1662 goto out;
1663 }
1664
1665 do_set_cpus_allowed(p, new_mask);
1666
1667 if (p->flags & PF_KTHREAD) {
1668 /*
1669 * For kernel threads that do indeed end up on online &&
1670 * !active we want to ensure they are strict per-CPU threads.
1671 */
1672 WARN_ON(cpumask_intersects(new_mask, cpu_online_mask) &&
1673 !cpumask_intersects(new_mask, cpu_active_mask) &&
1674 p->nr_cpus_allowed != 1);
1675 }
1676
1677 /* Can the task run on the task's current CPU? If so, we're done */
1678 if (cpumask_test_cpu(task_cpu(p), new_mask))
1679 goto out;
1680
1681 if (task_running(rq, p) || p->state == TASK_WAKING) {
1682 struct migration_arg arg = { p, dest_cpu };
1683 /* Need help from migration thread: drop lock and wait. */
1684 task_rq_unlock(rq, p, &rf);
1685 stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg);
1686 return 0;
1687 } else if (task_on_rq_queued(p)) {
1688 /*
1689 * OK, since we're going to drop the lock immediately
1690 * afterwards anyway.
1691 */
1692 rq = move_queued_task(rq, &rf, p, dest_cpu);
1693 }
1694out:
1695 task_rq_unlock(rq, p, &rf);
1696
1697 return ret;
1698}
1699
1700int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
1701{
1702 return __set_cpus_allowed_ptr(p, new_mask, false);
1703}
1704EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
1705
1706void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
1707{
1708#ifdef CONFIG_SCHED_DEBUG
1709 /*
1710 * We should never call set_task_cpu() on a blocked task,
1711 * ttwu() will sort out the placement.
1712 */
1713 WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING &&
1714 !p->on_rq);
1715
1716 /*
1717 * Migrating fair class task must have p->on_rq = TASK_ON_RQ_MIGRATING,
1718 * because schedstat_wait_{start,end} rebase migrating task's wait_start
1719 * time relying on p->on_rq.
1720 */
1721 WARN_ON_ONCE(p->state == TASK_RUNNING &&
1722 p->sched_class == &fair_sched_class &&
1723 (p->on_rq && !task_on_rq_migrating(p)));
1724
1725#ifdef CONFIG_LOCKDEP
1726 /*
1727 * The caller should hold either p->pi_lock or rq->lock, when changing
1728 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
1729 *
1730 * sched_move_task() holds both and thus holding either pins the cgroup,
1731 * see task_group().
1732 *
1733 * Furthermore, all task_rq users should acquire both locks, see
1734 * task_rq_lock().
1735 */
1736 WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) ||
1737 lockdep_is_held(&task_rq(p)->lock)));
1738#endif
1739 /*
1740 * Clearly, migrating tasks to offline CPUs is a fairly daft thing.
1741 */
1742 WARN_ON_ONCE(!cpu_online(new_cpu));
1743#endif
1744
1745 trace_sched_migrate_task(p, new_cpu);
1746
1747 if (task_cpu(p) != new_cpu) {
1748 if (p->sched_class->migrate_task_rq)
1749 p->sched_class->migrate_task_rq(p, new_cpu);
1750 p->se.nr_migrations++;
1751 rseq_migrate(p);
1752 perf_event_task_migrate(p);
1753 }
1754
1755 __set_task_cpu(p, new_cpu);
1756}
1757
1758#ifdef CONFIG_NUMA_BALANCING
1759static void __migrate_swap_task(struct task_struct *p, int cpu)
1760{
1761 if (task_on_rq_queued(p)) {
1762 struct rq *src_rq, *dst_rq;
1763 struct rq_flags srf, drf;
1764
1765 src_rq = task_rq(p);
1766 dst_rq = cpu_rq(cpu);
1767
1768 rq_pin_lock(src_rq, &srf);
1769 rq_pin_lock(dst_rq, &drf);
1770
1771 deactivate_task(src_rq, p, 0);
1772 set_task_cpu(p, cpu);
1773 activate_task(dst_rq, p, 0);
1774 check_preempt_curr(dst_rq, p, 0);
1775
1776 rq_unpin_lock(dst_rq, &drf);
1777 rq_unpin_lock(src_rq, &srf);
1778
1779 } else {
1780 /*
1781 * Task isn't running anymore; make it appear like we migrated
1782 * it before it went to sleep. This means on wakeup we make the
1783 * previous CPU our target instead of where it really is.
1784 */
1785 p->wake_cpu = cpu;
1786 }
1787}
1788
1789struct migration_swap_arg {
1790 struct task_struct *src_task, *dst_task;
1791 int src_cpu, dst_cpu;
1792};
1793
1794static int migrate_swap_stop(void *data)
1795{
1796 struct migration_swap_arg *arg = data;
1797 struct rq *src_rq, *dst_rq;
1798 int ret = -EAGAIN;
1799
1800 if (!cpu_active(arg->src_cpu) || !cpu_active(arg->dst_cpu))
1801 return -EAGAIN;
1802
1803 src_rq = cpu_rq(arg->src_cpu);
1804 dst_rq = cpu_rq(arg->dst_cpu);
1805
1806 double_raw_lock(&arg->src_task->pi_lock,
1807 &arg->dst_task->pi_lock);
1808 double_rq_lock(src_rq, dst_rq);
1809
1810 if (task_cpu(arg->dst_task) != arg->dst_cpu)
1811 goto unlock;
1812
1813 if (task_cpu(arg->src_task) != arg->src_cpu)
1814 goto unlock;
1815
1816 if (!cpumask_test_cpu(arg->dst_cpu, arg->src_task->cpus_ptr))
1817 goto unlock;
1818
1819 if (!cpumask_test_cpu(arg->src_cpu, arg->dst_task->cpus_ptr))
1820 goto unlock;
1821
1822 __migrate_swap_task(arg->src_task, arg->dst_cpu);
1823 __migrate_swap_task(arg->dst_task, arg->src_cpu);
1824
1825 ret = 0;
1826
1827unlock:
1828 double_rq_unlock(src_rq, dst_rq);
1829 raw_spin_unlock(&arg->dst_task->pi_lock);
1830 raw_spin_unlock(&arg->src_task->pi_lock);
1831
1832 return ret;
1833}
1834
1835/*
1836 * Cross migrate two tasks
1837 */
1838int migrate_swap(struct task_struct *cur, struct task_struct *p,
1839 int target_cpu, int curr_cpu)
1840{
1841 struct migration_swap_arg arg;
1842 int ret = -EINVAL;
1843
1844 arg = (struct migration_swap_arg){
1845 .src_task = cur,
1846 .src_cpu = curr_cpu,
1847 .dst_task = p,
1848 .dst_cpu = target_cpu,
1849 };
1850
1851 if (arg.src_cpu == arg.dst_cpu)
1852 goto out;
1853
1854 /*
1855 * These three tests are all lockless; this is OK since all of them
1856 * will be re-checked with proper locks held further down the line.
1857 */
1858 if (!cpu_active(arg.src_cpu) || !cpu_active(arg.dst_cpu))
1859 goto out;
1860
1861 if (!cpumask_test_cpu(arg.dst_cpu, arg.src_task->cpus_ptr))
1862 goto out;
1863
1864 if (!cpumask_test_cpu(arg.src_cpu, arg.dst_task->cpus_ptr))
1865 goto out;
1866
1867 trace_sched_swap_numa(cur, arg.src_cpu, p, arg.dst_cpu);
1868 ret = stop_two_cpus(arg.dst_cpu, arg.src_cpu, migrate_swap_stop, &arg);
1869
1870out:
1871 return ret;
1872}
1873#endif /* CONFIG_NUMA_BALANCING */
1874
1875/*
1876 * wait_task_inactive - wait for a thread to unschedule.
1877 *
1878 * If @match_state is nonzero, it's the @p->state value just checked and
1879 * not expected to change. If it changes, i.e. @p might have woken up,
1880 * then return zero. When we succeed in waiting for @p to be off its CPU,
1881 * we return a positive number (its total switch count). If a second call
1882 * a short while later returns the same number, the caller can be sure that
1883 * @p has remained unscheduled the whole time.
1884 *
1885 * The caller must ensure that the task *will* unschedule sometime soon,
1886 * else this function might spin for a *long* time. This function can't
1887 * be called with interrupts off, or it may introduce deadlock with
1888 * smp_call_function() if an IPI is sent by the same process we are
1889 * waiting to become inactive.
1890 */
1891unsigned long wait_task_inactive(struct task_struct *p, long match_state)
1892{
1893 int running, queued;
1894 struct rq_flags rf;
1895 unsigned long ncsw;
1896 struct rq *rq;
1897
1898 for (;;) {
1899 /*
1900 * We do the initial early heuristics without holding
1901 * any task-queue locks at all. We'll only try to get
1902 * the runqueue lock when things look like they will
1903 * work out!
1904 */
1905 rq = task_rq(p);
1906
1907 /*
1908 * If the task is actively running on another CPU
1909 * still, just relax and busy-wait without holding
1910 * any locks.
1911 *
1912 * NOTE! Since we don't hold any locks, it's not
1913 * even sure that "rq" stays as the right runqueue!
1914 * But we don't care, since "task_running()" will
1915 * return false if the runqueue has changed and p
1916 * is actually now running somewhere else!
1917 */
1918 while (task_running(rq, p)) {
1919 if (match_state && unlikely(p->state != match_state))
1920 return 0;
1921 cpu_relax();
1922 }
1923
1924 /*
1925 * Ok, time to look more closely! We need the rq
1926 * lock now, to be *sure*. If we're wrong, we'll
1927 * just go back and repeat.
1928 */
1929 rq = task_rq_lock(p, &rf);
1930 trace_sched_wait_task(p);
1931 running = task_running(rq, p);
1932 queued = task_on_rq_queued(p);
1933 ncsw = 0;
1934 if (!match_state || p->state == match_state)
1935 ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
1936 task_rq_unlock(rq, p, &rf);
1937
1938 /*
1939 * If it changed from the expected state, bail out now.
1940 */
1941 if (unlikely(!ncsw))
1942 break;
1943
1944 /*
1945 * Was it really running after all now that we
1946 * checked with the proper locks actually held?
1947 *
1948 * Oops. Go back and try again..
1949 */
1950 if (unlikely(running)) {
1951 cpu_relax();
1952 continue;
1953 }
1954
1955 /*
1956 * It's not enough that it's not actively running,
1957 * it must be off the runqueue _entirely_, and not
1958 * preempted!
1959 *
1960 * So if it was still runnable (but just not actively
1961 * running right now), it's preempted, and we should
1962 * yield - it could be a while.
1963 */
1964 if (unlikely(queued)) {
1965 ktime_t to = NSEC_PER_SEC / HZ;
1966
1967 set_current_state(TASK_UNINTERRUPTIBLE);
1968 schedule_hrtimeout(&to, HRTIMER_MODE_REL);
1969 continue;
1970 }
1971
1972 /*
1973 * Ahh, all good. It wasn't running, and it wasn't
1974 * runnable, which means that it will never become
1975 * running in the future either. We're all done!
1976 */
1977 break;
1978 }
1979
1980 return ncsw;
1981}
1982
1983/***
1984 * kick_process - kick a running thread to enter/exit the kernel
1985 * @p: the to-be-kicked thread
1986 *
1987 * Cause a process which is running on another CPU to enter
1988 * kernel-mode, without any delay. (to get signals handled.)
1989 *
1990 * NOTE: this function doesn't have to take the runqueue lock,
1991 * because all it wants to ensure is that the remote task enters
1992 * the kernel. If the IPI races and the task has been migrated
1993 * to another CPU then no harm is done and the purpose has been
1994 * achieved as well.
1995 */
1996void kick_process(struct task_struct *p)
1997{
1998 int cpu;
1999
2000 preempt_disable();
2001 cpu = task_cpu(p);
2002 if ((cpu != smp_processor_id()) && task_curr(p))
2003 smp_send_reschedule(cpu);
2004 preempt_enable();
2005}
2006EXPORT_SYMBOL_GPL(kick_process);
2007
2008/*
2009 * ->cpus_ptr is protected by both rq->lock and p->pi_lock
2010 *
2011 * A few notes on cpu_active vs cpu_online:
2012 *
2013 * - cpu_active must be a subset of cpu_online
2014 *
2015 * - on CPU-up we allow per-CPU kthreads on the online && !active CPU,
2016 * see __set_cpus_allowed_ptr(). At this point the newly online
2017 * CPU isn't yet part of the sched domains, and balancing will not
2018 * see it.
2019 *
2020 * - on CPU-down we clear cpu_active() to mask the sched domains and
2021 * avoid the load balancer to place new tasks on the to be removed
2022 * CPU. Existing tasks will remain running there and will be taken
2023 * off.
2024 *
2025 * This means that fallback selection must not select !active CPUs.
2026 * And can assume that any active CPU must be online. Conversely
2027 * select_task_rq() below may allow selection of !active CPUs in order
2028 * to satisfy the above rules.
2029 */
2030static int select_fallback_rq(int cpu, struct task_struct *p)
2031{
2032 int nid = cpu_to_node(cpu);
2033 const struct cpumask *nodemask = NULL;
2034 enum { cpuset, possible, fail } state = cpuset;
2035 int dest_cpu;
2036
2037 /*
2038 * If the node that the CPU is on has been offlined, cpu_to_node()
2039 * will return -1. There is no CPU on the node, and we should
2040 * select the CPU on the other node.
2041 */
2042 if (nid != -1) {
2043 nodemask = cpumask_of_node(nid);
2044
2045 /* Look for allowed, online CPU in same node. */
2046 for_each_cpu(dest_cpu, nodemask) {
2047 if (!cpu_active(dest_cpu))
2048 continue;
2049 if (cpumask_test_cpu(dest_cpu, p->cpus_ptr))
2050 return dest_cpu;
2051 }
2052 }
2053
2054 for (;;) {
2055 /* Any allowed, online CPU? */
2056 for_each_cpu(dest_cpu, p->cpus_ptr) {
2057 if (!is_cpu_allowed(p, dest_cpu))
2058 continue;
2059
2060 goto out;
2061 }
2062
2063 /* No more Mr. Nice Guy. */
2064 switch (state) {
2065 case cpuset:
2066 if (IS_ENABLED(CONFIG_CPUSETS)) {
2067 cpuset_cpus_allowed_fallback(p);
2068 state = possible;
2069 break;
2070 }
2071 /* Fall-through */
2072 case possible:
2073 do_set_cpus_allowed(p, cpu_possible_mask);
2074 state = fail;
2075 break;
2076
2077 case fail:
2078 BUG();
2079 break;
2080 }
2081 }
2082
2083out:
2084 if (state != cpuset) {
2085 /*
2086 * Don't tell them about moving exiting tasks or
2087 * kernel threads (both mm NULL), since they never
2088 * leave kernel.
2089 */
2090 if (p->mm && printk_ratelimit()) {
2091 printk_deferred("process %d (%s) no longer affine to cpu%d\n",
2092 task_pid_nr(p), p->comm, cpu);
2093 }
2094 }
2095
2096 return dest_cpu;
2097}
2098
2099/*
2100 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_ptr is stable.
2101 */
2102static inline
2103int select_task_rq(struct task_struct *p, int cpu, int sd_flags, int wake_flags)
2104{
2105 lockdep_assert_held(&p->pi_lock);
2106
2107 if (p->nr_cpus_allowed > 1)
2108 cpu = p->sched_class->select_task_rq(p, cpu, sd_flags, wake_flags);
2109 else
2110 cpu = cpumask_any(p->cpus_ptr);
2111
2112 /*
2113 * In order not to call set_task_cpu() on a blocking task we need
2114 * to rely on ttwu() to place the task on a valid ->cpus_ptr
2115 * CPU.
2116 *
2117 * Since this is common to all placement strategies, this lives here.
2118 *
2119 * [ this allows ->select_task() to simply return task_cpu(p) and
2120 * not worry about this generic constraint ]
2121 */
2122 if (unlikely(!is_cpu_allowed(p, cpu)))
2123 cpu = select_fallback_rq(task_cpu(p), p);
2124
2125 return cpu;
2126}
2127
2128static void update_avg(u64 *avg, u64 sample)
2129{
2130 s64 diff = sample - *avg;
2131 *avg += diff >> 3;
2132}
2133
2134void sched_set_stop_task(int cpu, struct task_struct *stop)
2135{
2136 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
2137 struct task_struct *old_stop = cpu_rq(cpu)->stop;
2138
2139 if (stop) {
2140 /*
2141 * Make it appear like a SCHED_FIFO task, its something
2142 * userspace knows about and won't get confused about.
2143 *
2144 * Also, it will make PI more or less work without too
2145 * much confusion -- but then, stop work should not
2146 * rely on PI working anyway.
2147 */
2148 sched_setscheduler_nocheck(stop, SCHED_FIFO, ¶m);
2149
2150 stop->sched_class = &stop_sched_class;
2151 }
2152
2153 cpu_rq(cpu)->stop = stop;
2154
2155 if (old_stop) {
2156 /*
2157 * Reset it back to a normal scheduling class so that
2158 * it can die in pieces.
2159 */
2160 old_stop->sched_class = &rt_sched_class;
2161 }
2162}
2163
2164#else
2165
2166static inline int __set_cpus_allowed_ptr(struct task_struct *p,
2167 const struct cpumask *new_mask, bool check)
2168{
2169 return set_cpus_allowed_ptr(p, new_mask);
2170}
2171
2172#endif /* CONFIG_SMP */
2173
2174static void
2175ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
2176{
2177 struct rq *rq;
2178
2179 if (!schedstat_enabled())
2180 return;
2181
2182 rq = this_rq();
2183
2184#ifdef CONFIG_SMP
2185 if (cpu == rq->cpu) {
2186 __schedstat_inc(rq->ttwu_local);
2187 __schedstat_inc(p->se.statistics.nr_wakeups_local);
2188 } else {
2189 struct sched_domain *sd;
2190
2191 __schedstat_inc(p->se.statistics.nr_wakeups_remote);
2192 rcu_read_lock();
2193 for_each_domain(rq->cpu, sd) {
2194 if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
2195 __schedstat_inc(sd->ttwu_wake_remote);
2196 break;
2197 }
2198 }
2199 rcu_read_unlock();
2200 }
2201
2202 if (wake_flags & WF_MIGRATED)
2203 __schedstat_inc(p->se.statistics.nr_wakeups_migrate);
2204#endif /* CONFIG_SMP */
2205
2206 __schedstat_inc(rq->ttwu_count);
2207 __schedstat_inc(p->se.statistics.nr_wakeups);
2208
2209 if (wake_flags & WF_SYNC)
2210 __schedstat_inc(p->se.statistics.nr_wakeups_sync);
2211}
2212
2213/*
2214 * Mark the task runnable and perform wakeup-preemption.
2215 */
2216static void ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags,
2217 struct rq_flags *rf)
2218{
2219 check_preempt_curr(rq, p, wake_flags);
2220 p->state = TASK_RUNNING;
2221 trace_sched_wakeup(p);
2222
2223#ifdef CONFIG_SMP
2224 if (p->sched_class->task_woken) {
2225 /*
2226 * Our task @p is fully woken up and running; so its safe to
2227 * drop the rq->lock, hereafter rq is only used for statistics.
2228 */
2229 rq_unpin_lock(rq, rf);
2230 p->sched_class->task_woken(rq, p);
2231 rq_repin_lock(rq, rf);
2232 }
2233
2234 if (rq->idle_stamp) {
2235 u64 delta = rq_clock(rq) - rq->idle_stamp;
2236 u64 max = 2*rq->max_idle_balance_cost;
2237
2238 update_avg(&rq->avg_idle, delta);
2239
2240 if (rq->avg_idle > max)
2241 rq->avg_idle = max;
2242
2243 rq->idle_stamp = 0;
2244 }
2245#endif
2246}
2247
2248static void
2249ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags,
2250 struct rq_flags *rf)
2251{
2252 int en_flags = ENQUEUE_WAKEUP | ENQUEUE_NOCLOCK;
2253
2254 lockdep_assert_held(&rq->lock);
2255
2256#ifdef CONFIG_SMP
2257 if (p->sched_contributes_to_load)
2258 rq->nr_uninterruptible--;
2259
2260 if (wake_flags & WF_MIGRATED)
2261 en_flags |= ENQUEUE_MIGRATED;
2262#endif
2263
2264 activate_task(rq, p, en_flags);
2265 ttwu_do_wakeup(rq, p, wake_flags, rf);
2266}
2267
2268/*
2269 * Called in case the task @p isn't fully descheduled from its runqueue,
2270 * in this case we must do a remote wakeup. Its a 'light' wakeup though,
2271 * since all we need to do is flip p->state to TASK_RUNNING, since
2272 * the task is still ->on_rq.
2273 */
2274static int ttwu_remote(struct task_struct *p, int wake_flags)
2275{
2276 struct rq_flags rf;
2277 struct rq *rq;
2278 int ret = 0;
2279
2280 rq = __task_rq_lock(p, &rf);
2281 if (task_on_rq_queued(p)) {
2282 /* check_preempt_curr() may use rq clock */
2283 update_rq_clock(rq);
2284 ttwu_do_wakeup(rq, p, wake_flags, &rf);
2285 ret = 1;
2286 }
2287 __task_rq_unlock(rq, &rf);
2288
2289 return ret;
2290}
2291
2292#ifdef CONFIG_SMP
2293void sched_ttwu_pending(void)
2294{
2295 struct rq *rq = this_rq();
2296 struct llist_node *llist = llist_del_all(&rq->wake_list);
2297 struct task_struct *p, *t;
2298 struct rq_flags rf;
2299
2300 if (!llist)
2301 return;
2302
2303 rq_lock_irqsave(rq, &rf);
2304 update_rq_clock(rq);
2305
2306 llist_for_each_entry_safe(p, t, llist, wake_entry)
2307 ttwu_do_activate(rq, p, p->sched_remote_wakeup ? WF_MIGRATED : 0, &rf);
2308
2309 rq_unlock_irqrestore(rq, &rf);
2310}
2311
2312void scheduler_ipi(void)
2313{
2314 /*
2315 * Fold TIF_NEED_RESCHED into the preempt_count; anybody setting
2316 * TIF_NEED_RESCHED remotely (for the first time) will also send
2317 * this IPI.
2318 */
2319 preempt_fold_need_resched();
2320
2321 if (llist_empty(&this_rq()->wake_list) && !got_nohz_idle_kick())
2322 return;
2323
2324 /*
2325 * Not all reschedule IPI handlers call irq_enter/irq_exit, since
2326 * traditionally all their work was done from the interrupt return
2327 * path. Now that we actually do some work, we need to make sure
2328 * we do call them.
2329 *
2330 * Some archs already do call them, luckily irq_enter/exit nest
2331 * properly.
2332 *
2333 * Arguably we should visit all archs and update all handlers,
2334 * however a fair share of IPIs are still resched only so this would
2335 * somewhat pessimize the simple resched case.
2336 */
2337 irq_enter();
2338 sched_ttwu_pending();
2339
2340 /*
2341 * Check if someone kicked us for doing the nohz idle load balance.
2342 */
2343 if (unlikely(got_nohz_idle_kick())) {
2344 this_rq()->idle_balance = 1;
2345 raise_softirq_irqoff(SCHED_SOFTIRQ);
2346 }
2347 irq_exit();
2348}
2349
2350static void ttwu_queue_remote(struct task_struct *p, int cpu, int wake_flags)
2351{
2352 struct rq *rq = cpu_rq(cpu);
2353
2354 p->sched_remote_wakeup = !!(wake_flags & WF_MIGRATED);
2355
2356 if (llist_add(&p->wake_entry, &cpu_rq(cpu)->wake_list)) {
2357 if (!set_nr_if_polling(rq->idle))
2358 smp_send_reschedule(cpu);
2359 else
2360 trace_sched_wake_idle_without_ipi(cpu);
2361 }
2362}
2363
2364void wake_up_if_idle(int cpu)
2365{
2366 struct rq *rq = cpu_rq(cpu);
2367 struct rq_flags rf;
2368
2369 rcu_read_lock();
2370
2371 if (!is_idle_task(rcu_dereference(rq->curr)))
2372 goto out;
2373
2374 if (set_nr_if_polling(rq->idle)) {
2375 trace_sched_wake_idle_without_ipi(cpu);
2376 } else {
2377 rq_lock_irqsave(rq, &rf);
2378 if (is_idle_task(rq->curr))
2379 smp_send_reschedule(cpu);
2380 /* Else CPU is not idle, do nothing here: */
2381 rq_unlock_irqrestore(rq, &rf);
2382 }
2383
2384out:
2385 rcu_read_unlock();
2386}
2387
2388bool cpus_share_cache(int this_cpu, int that_cpu)
2389{
2390 return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu);
2391}
2392#endif /* CONFIG_SMP */
2393
2394static void ttwu_queue(struct task_struct *p, int cpu, int wake_flags)
2395{
2396 struct rq *rq = cpu_rq(cpu);
2397 struct rq_flags rf;
2398
2399#if defined(CONFIG_SMP)
2400 if (sched_feat(TTWU_QUEUE) && !cpus_share_cache(smp_processor_id(), cpu)) {
2401 sched_clock_cpu(cpu); /* Sync clocks across CPUs */
2402 ttwu_queue_remote(p, cpu, wake_flags);
2403 return;
2404 }
2405#endif
2406
2407 rq_lock(rq, &rf);
2408 update_rq_clock(rq);
2409 ttwu_do_activate(rq, p, wake_flags, &rf);
2410 rq_unlock(rq, &rf);
2411}
2412
2413/*
2414 * Notes on Program-Order guarantees on SMP systems.
2415 *
2416 * MIGRATION
2417 *
2418 * The basic program-order guarantee on SMP systems is that when a task [t]
2419 * migrates, all its activity on its old CPU [c0] happens-before any subsequent
2420 * execution on its new CPU [c1].
2421 *
2422 * For migration (of runnable tasks) this is provided by the following means:
2423 *
2424 * A) UNLOCK of the rq(c0)->lock scheduling out task t
2425 * B) migration for t is required to synchronize *both* rq(c0)->lock and
2426 * rq(c1)->lock (if not at the same time, then in that order).
2427 * C) LOCK of the rq(c1)->lock scheduling in task
2428 *
2429 * Release/acquire chaining guarantees that B happens after A and C after B.
2430 * Note: the CPU doing B need not be c0 or c1
2431 *
2432 * Example:
2433 *
2434 * CPU0 CPU1 CPU2
2435 *
2436 * LOCK rq(0)->lock
2437 * sched-out X
2438 * sched-in Y
2439 * UNLOCK rq(0)->lock
2440 *
2441 * LOCK rq(0)->lock // orders against CPU0
2442 * dequeue X
2443 * UNLOCK rq(0)->lock
2444 *
2445 * LOCK rq(1)->lock
2446 * enqueue X
2447 * UNLOCK rq(1)->lock
2448 *
2449 * LOCK rq(1)->lock // orders against CPU2
2450 * sched-out Z
2451 * sched-in X
2452 * UNLOCK rq(1)->lock
2453 *
2454 *
2455 * BLOCKING -- aka. SLEEP + WAKEUP
2456 *
2457 * For blocking we (obviously) need to provide the same guarantee as for
2458 * migration. However the means are completely different as there is no lock
2459 * chain to provide order. Instead we do:
2460 *
2461 * 1) smp_store_release(X->on_cpu, 0)
2462 * 2) smp_cond_load_acquire(!X->on_cpu)
2463 *
2464 * Example:
2465 *
2466 * CPU0 (schedule) CPU1 (try_to_wake_up) CPU2 (schedule)
2467 *
2468 * LOCK rq(0)->lock LOCK X->pi_lock
2469 * dequeue X
2470 * sched-out X
2471 * smp_store_release(X->on_cpu, 0);
2472 *
2473 * smp_cond_load_acquire(&X->on_cpu, !VAL);
2474 * X->state = WAKING
2475 * set_task_cpu(X,2)
2476 *
2477 * LOCK rq(2)->lock
2478 * enqueue X
2479 * X->state = RUNNING
2480 * UNLOCK rq(2)->lock
2481 *
2482 * LOCK rq(2)->lock // orders against CPU1
2483 * sched-out Z
2484 * sched-in X
2485 * UNLOCK rq(2)->lock
2486 *
2487 * UNLOCK X->pi_lock
2488 * UNLOCK rq(0)->lock
2489 *
2490 *
2491 * However, for wakeups there is a second guarantee we must provide, namely we
2492 * must ensure that CONDITION=1 done by the caller can not be reordered with
2493 * accesses to the task state; see try_to_wake_up() and set_current_state().
2494 */
2495
2496/**
2497 * try_to_wake_up - wake up a thread
2498 * @p: the thread to be awakened
2499 * @state: the mask of task states that can be woken
2500 * @wake_flags: wake modifier flags (WF_*)
2501 *
2502 * If (@state & @p->state) @p->state = TASK_RUNNING.
2503 *
2504 * If the task was not queued/runnable, also place it back on a runqueue.
2505 *
2506 * Atomic against schedule() which would dequeue a task, also see
2507 * set_current_state().
2508 *
2509 * This function executes a full memory barrier before accessing the task
2510 * state; see set_current_state().
2511 *
2512 * Return: %true if @p->state changes (an actual wakeup was done),
2513 * %false otherwise.
2514 */
2515static int
2516try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
2517{
2518 unsigned long flags;
2519 int cpu, success = 0;
2520
2521 preempt_disable();
2522 if (p == current) {
2523 /*
2524 * We're waking current, this means 'p->on_rq' and 'task_cpu(p)
2525 * == smp_processor_id()'. Together this means we can special
2526 * case the whole 'p->on_rq && ttwu_remote()' case below
2527 * without taking any locks.
2528 *
2529 * In particular:
2530 * - we rely on Program-Order guarantees for all the ordering,
2531 * - we're serialized against set_special_state() by virtue of
2532 * it disabling IRQs (this allows not taking ->pi_lock).
2533 */
2534 if (!(p->state & state))
2535 goto out;
2536
2537 success = 1;
2538 cpu = task_cpu(p);
2539 trace_sched_waking(p);
2540 p->state = TASK_RUNNING;
2541 trace_sched_wakeup(p);
2542 goto out;
2543 }
2544
2545 /*
2546 * If we are going to wake up a thread waiting for CONDITION we
2547 * need to ensure that CONDITION=1 done by the caller can not be
2548 * reordered with p->state check below. This pairs with mb() in
2549 * set_current_state() the waiting thread does.
2550 */
2551 raw_spin_lock_irqsave(&p->pi_lock, flags);
2552 smp_mb__after_spinlock();
2553 if (!(p->state & state))
2554 goto unlock;
2555
2556 trace_sched_waking(p);
2557
2558 /* We're going to change ->state: */
2559 success = 1;
2560 cpu = task_cpu(p);
2561
2562 /*
2563 * Ensure we load p->on_rq _after_ p->state, otherwise it would
2564 * be possible to, falsely, observe p->on_rq == 0 and get stuck
2565 * in smp_cond_load_acquire() below.
2566 *
2567 * sched_ttwu_pending() try_to_wake_up()
2568 * STORE p->on_rq = 1 LOAD p->state
2569 * UNLOCK rq->lock
2570 *
2571 * __schedule() (switch to task 'p')
2572 * LOCK rq->lock smp_rmb();
2573 * smp_mb__after_spinlock();
2574 * UNLOCK rq->lock
2575 *
2576 * [task p]
2577 * STORE p->state = UNINTERRUPTIBLE LOAD p->on_rq
2578 *
2579 * Pairs with the LOCK+smp_mb__after_spinlock() on rq->lock in
2580 * __schedule(). See the comment for smp_mb__after_spinlock().
2581 */
2582 smp_rmb();
2583 if (p->on_rq && ttwu_remote(p, wake_flags))
2584 goto unlock;
2585
2586#ifdef CONFIG_SMP
2587 /*
2588 * Ensure we load p->on_cpu _after_ p->on_rq, otherwise it would be
2589 * possible to, falsely, observe p->on_cpu == 0.
2590 *
2591 * One must be running (->on_cpu == 1) in order to remove oneself
2592 * from the runqueue.
2593 *
2594 * __schedule() (switch to task 'p') try_to_wake_up()
2595 * STORE p->on_cpu = 1 LOAD p->on_rq
2596 * UNLOCK rq->lock
2597 *
2598 * __schedule() (put 'p' to sleep)
2599 * LOCK rq->lock smp_rmb();
2600 * smp_mb__after_spinlock();
2601 * STORE p->on_rq = 0 LOAD p->on_cpu
2602 *
2603 * Pairs with the LOCK+smp_mb__after_spinlock() on rq->lock in
2604 * __schedule(). See the comment for smp_mb__after_spinlock().
2605 */
2606 smp_rmb();
2607
2608 /*
2609 * If the owning (remote) CPU is still in the middle of schedule() with
2610 * this task as prev, wait until its done referencing the task.
2611 *
2612 * Pairs with the smp_store_release() in finish_task().
2613 *
2614 * This ensures that tasks getting woken will be fully ordered against
2615 * their previous state and preserve Program Order.
2616 */
2617 smp_cond_load_acquire(&p->on_cpu, !VAL);
2618
2619 p->sched_contributes_to_load = !!task_contributes_to_load(p);
2620 p->state = TASK_WAKING;
2621
2622 if (p->in_iowait) {
2623 delayacct_blkio_end(p);
2624 atomic_dec(&task_rq(p)->nr_iowait);
2625 }
2626
2627 cpu = select_task_rq(p, p->wake_cpu, SD_BALANCE_WAKE, wake_flags);
2628 if (task_cpu(p) != cpu) {
2629 wake_flags |= WF_MIGRATED;
2630 psi_ttwu_dequeue(p);
2631 set_task_cpu(p, cpu);
2632 }
2633
2634#else /* CONFIG_SMP */
2635
2636 if (p->in_iowait) {
2637 delayacct_blkio_end(p);
2638 atomic_dec(&task_rq(p)->nr_iowait);
2639 }
2640
2641#endif /* CONFIG_SMP */
2642
2643 ttwu_queue(p, cpu, wake_flags);
2644unlock:
2645 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
2646out:
2647 if (success)
2648 ttwu_stat(p, cpu, wake_flags);
2649 preempt_enable();
2650
2651 return success;
2652}
2653
2654/**
2655 * wake_up_process - Wake up a specific process
2656 * @p: The process to be woken up.
2657 *
2658 * Attempt to wake up the nominated process and move it to the set of runnable
2659 * processes.
2660 *
2661 * Return: 1 if the process was woken up, 0 if it was already running.
2662 *
2663 * This function executes a full memory barrier before accessing the task state.
2664 */
2665int wake_up_process(struct task_struct *p)
2666{
2667 return try_to_wake_up(p, TASK_NORMAL, 0);
2668}
2669EXPORT_SYMBOL(wake_up_process);
2670
2671int wake_up_state(struct task_struct *p, unsigned int state)
2672{
2673 return try_to_wake_up(p, state, 0);
2674}
2675
2676/*
2677 * Perform scheduler related setup for a newly forked process p.
2678 * p is forked by current.
2679 *
2680 * __sched_fork() is basic setup used by init_idle() too:
2681 */
2682static void __sched_fork(unsigned long clone_flags, struct task_struct *p)
2683{
2684 p->on_rq = 0;
2685
2686 p->se.on_rq = 0;
2687 p->se.exec_start = 0;
2688 p->se.sum_exec_runtime = 0;
2689 p->se.prev_sum_exec_runtime = 0;
2690 p->se.nr_migrations = 0;
2691 p->se.vruntime = 0;
2692 INIT_LIST_HEAD(&p->se.group_node);
2693
2694#ifdef CONFIG_FAIR_GROUP_SCHED
2695 p->se.cfs_rq = NULL;
2696#endif
2697
2698#ifdef CONFIG_SCHEDSTATS
2699 /* Even if schedstat is disabled, there should not be garbage */
2700 memset(&p->se.statistics, 0, sizeof(p->se.statistics));
2701#endif
2702
2703 RB_CLEAR_NODE(&p->dl.rb_node);
2704 init_dl_task_timer(&p->dl);
2705 init_dl_inactive_task_timer(&p->dl);
2706 __dl_clear_params(p);
2707
2708 INIT_LIST_HEAD(&p->rt.run_list);
2709 p->rt.timeout = 0;
2710 p->rt.time_slice = sched_rr_timeslice;
2711 p->rt.on_rq = 0;
2712 p->rt.on_list = 0;
2713
2714#ifdef CONFIG_PREEMPT_NOTIFIERS
2715 INIT_HLIST_HEAD(&p->preempt_notifiers);
2716#endif
2717
2718#ifdef CONFIG_COMPACTION
2719 p->capture_control = NULL;
2720#endif
2721 init_numa_balancing(clone_flags, p);
2722}
2723
2724DEFINE_STATIC_KEY_FALSE(sched_numa_balancing);
2725
2726#ifdef CONFIG_NUMA_BALANCING
2727
2728void set_numabalancing_state(bool enabled)
2729{
2730 if (enabled)
2731 static_branch_enable(&sched_numa_balancing);
2732 else
2733 static_branch_disable(&sched_numa_balancing);
2734}
2735
2736#ifdef CONFIG_PROC_SYSCTL
2737int sysctl_numa_balancing(struct ctl_table *table, int write,
2738 void __user *buffer, size_t *lenp, loff_t *ppos)
2739{
2740 struct ctl_table t;
2741 int err;
2742 int state = static_branch_likely(&sched_numa_balancing);
2743
2744 if (write && !capable(CAP_SYS_ADMIN))
2745 return -EPERM;
2746
2747 t = *table;
2748 t.data = &state;
2749 err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos);
2750 if (err < 0)
2751 return err;
2752 if (write)
2753 set_numabalancing_state(state);
2754 return err;
2755}
2756#endif
2757#endif
2758
2759#ifdef CONFIG_SCHEDSTATS
2760
2761DEFINE_STATIC_KEY_FALSE(sched_schedstats);
2762static bool __initdata __sched_schedstats = false;
2763
2764static void set_schedstats(bool enabled)
2765{
2766 if (enabled)
2767 static_branch_enable(&sched_schedstats);
2768 else
2769 static_branch_disable(&sched_schedstats);
2770}
2771
2772void force_schedstat_enabled(void)
2773{
2774 if (!schedstat_enabled()) {
2775 pr_info("kernel profiling enabled schedstats, disable via kernel.sched_schedstats.\n");
2776 static_branch_enable(&sched_schedstats);
2777 }
2778}
2779
2780static int __init setup_schedstats(char *str)
2781{
2782 int ret = 0;
2783 if (!str)
2784 goto out;
2785
2786 /*
2787 * This code is called before jump labels have been set up, so we can't
2788 * change the static branch directly just yet. Instead set a temporary
2789 * variable so init_schedstats() can do it later.
2790 */
2791 if (!strcmp(str, "enable")) {
2792 __sched_schedstats = true;
2793 ret = 1;
2794 } else if (!strcmp(str, "disable")) {
2795 __sched_schedstats = false;
2796 ret = 1;
2797 }
2798out:
2799 if (!ret)
2800 pr_warn("Unable to parse schedstats=\n");
2801
2802 return ret;
2803}
2804__setup("schedstats=", setup_schedstats);
2805
2806static void __init init_schedstats(void)
2807{
2808 set_schedstats(__sched_schedstats);
2809}
2810
2811#ifdef CONFIG_PROC_SYSCTL
2812int sysctl_schedstats(struct ctl_table *table, int write,
2813 void __user *buffer, size_t *lenp, loff_t *ppos)
2814{
2815 struct ctl_table t;
2816 int err;
2817 int state = static_branch_likely(&sched_schedstats);
2818
2819 if (write && !capable(CAP_SYS_ADMIN))
2820 return -EPERM;
2821
2822 t = *table;
2823 t.data = &state;
2824 err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos);
2825 if (err < 0)
2826 return err;
2827 if (write)
2828 set_schedstats(state);
2829 return err;
2830}
2831#endif /* CONFIG_PROC_SYSCTL */
2832#else /* !CONFIG_SCHEDSTATS */
2833static inline void init_schedstats(void) {}
2834#endif /* CONFIG_SCHEDSTATS */
2835
2836/*
2837 * fork()/clone()-time setup:
2838 */
2839int sched_fork(unsigned long clone_flags, struct task_struct *p)
2840{
2841 unsigned long flags;
2842
2843 __sched_fork(clone_flags, p);
2844 /*
2845 * We mark the process as NEW here. This guarantees that
2846 * nobody will actually run it, and a signal or other external
2847 * event cannot wake it up and insert it on the runqueue either.
2848 */
2849 p->state = TASK_NEW;
2850
2851 /*
2852 * Make sure we do not leak PI boosting priority to the child.
2853 */
2854 p->prio = current->normal_prio;
2855
2856 uclamp_fork(p);
2857
2858 /*
2859 * Revert to default priority/policy on fork if requested.
2860 */
2861 if (unlikely(p->sched_reset_on_fork)) {
2862 if (task_has_dl_policy(p) || task_has_rt_policy(p)) {
2863 p->policy = SCHED_NORMAL;
2864 p->static_prio = NICE_TO_PRIO(0);
2865 p->rt_priority = 0;
2866 } else if (PRIO_TO_NICE(p->static_prio) < 0)
2867 p->static_prio = NICE_TO_PRIO(0);
2868
2869 p->prio = p->normal_prio = __normal_prio(p);
2870 set_load_weight(p, false);
2871
2872 /*
2873 * We don't need the reset flag anymore after the fork. It has
2874 * fulfilled its duty:
2875 */
2876 p->sched_reset_on_fork = 0;
2877 }
2878
2879 if (dl_prio(p->prio))
2880 return -EAGAIN;
2881 else if (rt_prio(p->prio))
2882 p->sched_class = &rt_sched_class;
2883 else
2884 p->sched_class = &fair_sched_class;
2885
2886 init_entity_runnable_average(&p->se);
2887
2888 /*
2889 * The child is not yet in the pid-hash so no cgroup attach races,
2890 * and the cgroup is pinned to this child due to cgroup_fork()
2891 * is ran before sched_fork().
2892 *
2893 * Silence PROVE_RCU.
2894 */
2895 raw_spin_lock_irqsave(&p->pi_lock, flags);
2896 /*
2897 * We're setting the CPU for the first time, we don't migrate,
2898 * so use __set_task_cpu().
2899 */
2900 __set_task_cpu(p, smp_processor_id());
2901 if (p->sched_class->task_fork)
2902 p->sched_class->task_fork(p);
2903 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
2904
2905#ifdef CONFIG_SCHED_INFO
2906 if (likely(sched_info_on()))
2907 memset(&p->sched_info, 0, sizeof(p->sched_info));
2908#endif
2909#if defined(CONFIG_SMP)
2910 p->on_cpu = 0;
2911#endif
2912 init_task_preempt_count(p);
2913#ifdef CONFIG_SMP
2914 plist_node_init(&p->pushable_tasks, MAX_PRIO);
2915 RB_CLEAR_NODE(&p->pushable_dl_tasks);
2916#endif
2917 return 0;
2918}
2919
2920unsigned long to_ratio(u64 period, u64 runtime)
2921{
2922 if (runtime == RUNTIME_INF)
2923 return BW_UNIT;
2924
2925 /*
2926 * Doing this here saves a lot of checks in all
2927 * the calling paths, and returning zero seems
2928 * safe for them anyway.
2929 */
2930 if (period == 0)
2931 return 0;
2932
2933 return div64_u64(runtime << BW_SHIFT, period);
2934}
2935
2936/*
2937 * wake_up_new_task - wake up a newly created task for the first time.
2938 *
2939 * This function will do some initial scheduler statistics housekeeping
2940 * that must be done for every newly created context, then puts the task
2941 * on the runqueue and wakes it.
2942 */
2943void wake_up_new_task(struct task_struct *p)
2944{
2945 struct rq_flags rf;
2946 struct rq *rq;
2947
2948 raw_spin_lock_irqsave(&p->pi_lock, rf.flags);
2949 p->state = TASK_RUNNING;
2950#ifdef CONFIG_SMP
2951 /*
2952 * Fork balancing, do it here and not earlier because:
2953 * - cpus_ptr can change in the fork path
2954 * - any previously selected CPU might disappear through hotplug
2955 *
2956 * Use __set_task_cpu() to avoid calling sched_class::migrate_task_rq,
2957 * as we're not fully set-up yet.
2958 */
2959 p->recent_used_cpu = task_cpu(p);
2960 __set_task_cpu(p, select_task_rq(p, task_cpu(p), SD_BALANCE_FORK, 0));
2961#endif
2962 rq = __task_rq_lock(p, &rf);
2963 update_rq_clock(rq);
2964 post_init_entity_util_avg(p);
2965
2966 activate_task(rq, p, ENQUEUE_NOCLOCK);
2967 trace_sched_wakeup_new(p);
2968 check_preempt_curr(rq, p, WF_FORK);
2969#ifdef CONFIG_SMP
2970 if (p->sched_class->task_woken) {
2971 /*
2972 * Nothing relies on rq->lock after this, so its fine to
2973 * drop it.
2974 */
2975 rq_unpin_lock(rq, &rf);
2976 p->sched_class->task_woken(rq, p);
2977 rq_repin_lock(rq, &rf);
2978 }
2979#endif
2980 task_rq_unlock(rq, p, &rf);
2981}
2982
2983#ifdef CONFIG_PREEMPT_NOTIFIERS
2984
2985static DEFINE_STATIC_KEY_FALSE(preempt_notifier_key);
2986
2987void preempt_notifier_inc(void)
2988{
2989 static_branch_inc(&preempt_notifier_key);
2990}
2991EXPORT_SYMBOL_GPL(preempt_notifier_inc);
2992
2993void preempt_notifier_dec(void)
2994{
2995 static_branch_dec(&preempt_notifier_key);
2996}
2997EXPORT_SYMBOL_GPL(preempt_notifier_dec);
2998
2999/**
3000 * preempt_notifier_register - tell me when current is being preempted & rescheduled
3001 * @notifier: notifier struct to register
3002 */
3003void preempt_notifier_register(struct preempt_notifier *notifier)
3004{
3005 if (!static_branch_unlikely(&preempt_notifier_key))
3006 WARN(1, "registering preempt_notifier while notifiers disabled\n");
3007
3008 hlist_add_head(¬ifier->link, ¤t->preempt_notifiers);
3009}
3010EXPORT_SYMBOL_GPL(preempt_notifier_register);
3011
3012/**
3013 * preempt_notifier_unregister - no longer interested in preemption notifications
3014 * @notifier: notifier struct to unregister
3015 *
3016 * This is *not* safe to call from within a preemption notifier.
3017 */
3018void preempt_notifier_unregister(struct preempt_notifier *notifier)
3019{
3020 hlist_del(¬ifier->link);
3021}
3022EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
3023
3024static void __fire_sched_in_preempt_notifiers(struct task_struct *curr)
3025{
3026 struct preempt_notifier *notifier;
3027
3028 hlist_for_each_entry(notifier, &curr->preempt_notifiers, link)
3029 notifier->ops->sched_in(notifier, raw_smp_processor_id());
3030}
3031
3032static __always_inline void fire_sched_in_preempt_notifiers(struct task_struct *curr)
3033{
3034 if (static_branch_unlikely(&preempt_notifier_key))
3035 __fire_sched_in_preempt_notifiers(curr);
3036}
3037
3038static void
3039__fire_sched_out_preempt_notifiers(struct task_struct *curr,
3040 struct task_struct *next)
3041{
3042 struct preempt_notifier *notifier;
3043
3044 hlist_for_each_entry(notifier, &curr->preempt_notifiers, link)
3045 notifier->ops->sched_out(notifier, next);
3046}
3047
3048static __always_inline void
3049fire_sched_out_preempt_notifiers(struct task_struct *curr,
3050 struct task_struct *next)
3051{
3052 if (static_branch_unlikely(&preempt_notifier_key))
3053 __fire_sched_out_preempt_notifiers(curr, next);
3054}
3055
3056#else /* !CONFIG_PREEMPT_NOTIFIERS */
3057
3058static inline void fire_sched_in_preempt_notifiers(struct task_struct *curr)
3059{
3060}
3061
3062static inline void
3063fire_sched_out_preempt_notifiers(struct task_struct *curr,
3064 struct task_struct *next)
3065{
3066}
3067
3068#endif /* CONFIG_PREEMPT_NOTIFIERS */
3069
3070static inline void prepare_task(struct task_struct *next)
3071{
3072#ifdef CONFIG_SMP
3073 /*
3074 * Claim the task as running, we do this before switching to it
3075 * such that any running task will have this set.
3076 */
3077 next->on_cpu = 1;
3078#endif
3079}
3080
3081static inline void finish_task(struct task_struct *prev)
3082{
3083#ifdef CONFIG_SMP
3084 /*
3085 * After ->on_cpu is cleared, the task can be moved to a different CPU.
3086 * We must ensure this doesn't happen until the switch is completely
3087 * finished.
3088 *
3089 * In particular, the load of prev->state in finish_task_switch() must
3090 * happen before this.
3091 *
3092 * Pairs with the smp_cond_load_acquire() in try_to_wake_up().
3093 */
3094 smp_store_release(&prev->on_cpu, 0);
3095#endif
3096}
3097
3098static inline void
3099prepare_lock_switch(struct rq *rq, struct task_struct *next, struct rq_flags *rf)
3100{
3101 /*
3102 * Since the runqueue lock will be released by the next
3103 * task (which is an invalid locking op but in the case
3104 * of the scheduler it's an obvious special-case), so we
3105 * do an early lockdep release here:
3106 */
3107 rq_unpin_lock(rq, rf);
3108 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
3109#ifdef CONFIG_DEBUG_SPINLOCK
3110 /* this is a valid case when another task releases the spinlock */
3111 rq->lock.owner = next;
3112#endif
3113}
3114
3115static inline void finish_lock_switch(struct rq *rq)
3116{
3117 /*
3118 * If we are tracking spinlock dependencies then we have to
3119 * fix up the runqueue lock - which gets 'carried over' from
3120 * prev into current:
3121 */
3122 spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_);
3123 raw_spin_unlock_irq(&rq->lock);
3124}
3125
3126/*
3127 * NOP if the arch has not defined these:
3128 */
3129
3130#ifndef prepare_arch_switch
3131# define prepare_arch_switch(next) do { } while (0)
3132#endif
3133
3134#ifndef finish_arch_post_lock_switch
3135# define finish_arch_post_lock_switch() do { } while (0)
3136#endif
3137
3138/**
3139 * prepare_task_switch - prepare to switch tasks
3140 * @rq: the runqueue preparing to switch
3141 * @prev: the current task that is being switched out
3142 * @next: the task we are going to switch to.
3143 *
3144 * This is called with the rq lock held and interrupts off. It must
3145 * be paired with a subsequent finish_task_switch after the context
3146 * switch.
3147 *
3148 * prepare_task_switch sets up locking and calls architecture specific
3149 * hooks.
3150 */
3151static inline void
3152prepare_task_switch(struct rq *rq, struct task_struct *prev,
3153 struct task_struct *next)
3154{
3155 kcov_prepare_switch(prev);
3156 sched_info_switch(rq, prev, next);
3157 perf_event_task_sched_out(prev, next);
3158 rseq_preempt(prev);
3159 fire_sched_out_preempt_notifiers(prev, next);
3160 prepare_task(next);
3161 prepare_arch_switch(next);
3162}
3163
3164/**
3165 * finish_task_switch - clean up after a task-switch
3166 * @prev: the thread we just switched away from.
3167 *
3168 * finish_task_switch must be called after the context switch, paired
3169 * with a prepare_task_switch call before the context switch.
3170 * finish_task_switch will reconcile locking set up by prepare_task_switch,
3171 * and do any other architecture-specific cleanup actions.
3172 *
3173 * Note that we may have delayed dropping an mm in context_switch(). If
3174 * so, we finish that here outside of the runqueue lock. (Doing it
3175 * with the lock held can cause deadlocks; see schedule() for
3176 * details.)
3177 *
3178 * The context switch have flipped the stack from under us and restored the
3179 * local variables which were saved when this task called schedule() in the
3180 * past. prev == current is still correct but we need to recalculate this_rq
3181 * because prev may have moved to another CPU.
3182 */
3183static struct rq *finish_task_switch(struct task_struct *prev)
3184 __releases(rq->lock)
3185{
3186 struct rq *rq = this_rq();
3187 struct mm_struct *mm = rq->prev_mm;
3188 long prev_state;
3189
3190 /*
3191 * The previous task will have left us with a preempt_count of 2
3192 * because it left us after:
3193 *
3194 * schedule()
3195 * preempt_disable(); // 1
3196 * __schedule()
3197 * raw_spin_lock_irq(&rq->lock) // 2
3198 *
3199 * Also, see FORK_PREEMPT_COUNT.
3200 */
3201 if (WARN_ONCE(preempt_count() != 2*PREEMPT_DISABLE_OFFSET,
3202 "corrupted preempt_count: %s/%d/0x%x\n",
3203 current->comm, current->pid, preempt_count()))
3204 preempt_count_set(FORK_PREEMPT_COUNT);
3205
3206 rq->prev_mm = NULL;
3207
3208 /*
3209 * A task struct has one reference for the use as "current".
3210 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
3211 * schedule one last time. The schedule call will never return, and
3212 * the scheduled task must drop that reference.
3213 *
3214 * We must observe prev->state before clearing prev->on_cpu (in
3215 * finish_task), otherwise a concurrent wakeup can get prev
3216 * running on another CPU and we could rave with its RUNNING -> DEAD
3217 * transition, resulting in a double drop.
3218 */
3219 prev_state = prev->state;
3220 vtime_task_switch(prev);
3221 perf_event_task_sched_in(prev, current);
3222 finish_task(prev);
3223 finish_lock_switch(rq);
3224 finish_arch_post_lock_switch();
3225 kcov_finish_switch(current);
3226
3227 fire_sched_in_preempt_notifiers(current);
3228 /*
3229 * When switching through a kernel thread, the loop in
3230 * membarrier_{private,global}_expedited() may have observed that
3231 * kernel thread and not issued an IPI. It is therefore possible to
3232 * schedule between user->kernel->user threads without passing though
3233 * switch_mm(). Membarrier requires a barrier after storing to
3234 * rq->curr, before returning to userspace, so provide them here:
3235 *
3236 * - a full memory barrier for {PRIVATE,GLOBAL}_EXPEDITED, implicitly
3237 * provided by mmdrop(),
3238 * - a sync_core for SYNC_CORE.
3239 */
3240 if (mm) {
3241 membarrier_mm_sync_core_before_usermode(mm);
3242 mmdrop(mm);
3243 }
3244 if (unlikely(prev_state == TASK_DEAD)) {
3245 if (prev->sched_class->task_dead)
3246 prev->sched_class->task_dead(prev);
3247
3248 /*
3249 * Remove function-return probe instances associated with this
3250 * task and put them back on the free list.
3251 */
3252 kprobe_flush_task(prev);
3253
3254 /* Task is done with its stack. */
3255 put_task_stack(prev);
3256
3257 put_task_struct_rcu_user(prev);
3258 }
3259
3260 tick_nohz_task_switch();
3261 return rq;
3262}
3263
3264#ifdef CONFIG_SMP
3265
3266/* rq->lock is NOT held, but preemption is disabled */
3267static void __balance_callback(struct rq *rq)
3268{
3269 struct callback_head *head, *next;
3270 void (*func)(struct rq *rq);
3271 unsigned long flags;
3272
3273 raw_spin_lock_irqsave(&rq->lock, flags);
3274 head = rq->balance_callback;
3275 rq->balance_callback = NULL;
3276 while (head) {
3277 func = (void (*)(struct rq *))head->func;
3278 next = head->next;
3279 head->next = NULL;
3280 head = next;
3281
3282 func(rq);
3283 }
3284 raw_spin_unlock_irqrestore(&rq->lock, flags);
3285}
3286
3287static inline void balance_callback(struct rq *rq)
3288{
3289 if (unlikely(rq->balance_callback))
3290 __balance_callback(rq);
3291}
3292
3293#else
3294
3295static inline void balance_callback(struct rq *rq)
3296{
3297}
3298
3299#endif
3300
3301/**
3302 * schedule_tail - first thing a freshly forked thread must call.
3303 * @prev: the thread we just switched away from.
3304 */
3305asmlinkage __visible void schedule_tail(struct task_struct *prev)
3306 __releases(rq->lock)
3307{
3308 struct rq *rq;
3309
3310 /*
3311 * New tasks start with FORK_PREEMPT_COUNT, see there and
3312 * finish_task_switch() for details.
3313 *
3314 * finish_task_switch() will drop rq->lock() and lower preempt_count
3315 * and the preempt_enable() will end up enabling preemption (on
3316 * PREEMPT_COUNT kernels).
3317 */
3318
3319 rq = finish_task_switch(prev);
3320 balance_callback(rq);
3321 preempt_enable();
3322
3323 if (current->set_child_tid)
3324 put_user(task_pid_vnr(current), current->set_child_tid);
3325
3326 calculate_sigpending();
3327}
3328
3329/*
3330 * context_switch - switch to the new MM and the new thread's register state.
3331 */
3332static __always_inline struct rq *
3333context_switch(struct rq *rq, struct task_struct *prev,
3334 struct task_struct *next, struct rq_flags *rf)
3335{
3336 prepare_task_switch(rq, prev, next);
3337
3338 /*
3339 * For paravirt, this is coupled with an exit in switch_to to
3340 * combine the page table reload and the switch backend into
3341 * one hypercall.
3342 */
3343 arch_start_context_switch(prev);
3344
3345 /*
3346 * kernel -> kernel lazy + transfer active
3347 * user -> kernel lazy + mmgrab() active
3348 *
3349 * kernel -> user switch + mmdrop() active
3350 * user -> user switch
3351 */
3352 if (!next->mm) { // to kernel
3353 enter_lazy_tlb(prev->active_mm, next);
3354
3355 next->active_mm = prev->active_mm;
3356 if (prev->mm) // from user
3357 mmgrab(prev->active_mm);
3358 else
3359 prev->active_mm = NULL;
3360 } else { // to user
3361 membarrier_switch_mm(rq, prev->active_mm, next->mm);
3362 /*
3363 * sys_membarrier() requires an smp_mb() between setting
3364 * rq->curr / membarrier_switch_mm() and returning to userspace.
3365 *
3366 * The below provides this either through switch_mm(), or in
3367 * case 'prev->active_mm == next->mm' through
3368 * finish_task_switch()'s mmdrop().
3369 */
3370 switch_mm_irqs_off(prev->active_mm, next->mm, next);
3371
3372 if (!prev->mm) { // from kernel
3373 /* will mmdrop() in finish_task_switch(). */
3374 rq->prev_mm = prev->active_mm;
3375 prev->active_mm = NULL;
3376 }
3377 }
3378
3379 rq->clock_update_flags &= ~(RQCF_ACT_SKIP|RQCF_REQ_SKIP);
3380
3381 prepare_lock_switch(rq, next, rf);
3382
3383 /* Here we just switch the register state and the stack. */
3384 switch_to(prev, next, prev);
3385 barrier();
3386
3387 return finish_task_switch(prev);
3388}
3389
3390/*
3391 * nr_running and nr_context_switches:
3392 *
3393 * externally visible scheduler statistics: current number of runnable
3394 * threads, total number of context switches performed since bootup.
3395 */
3396unsigned long nr_running(void)
3397{
3398 unsigned long i, sum = 0;
3399
3400 for_each_online_cpu(i)
3401 sum += cpu_rq(i)->nr_running;
3402
3403 return sum;
3404}
3405
3406/*
3407 * Check if only the current task is running on the CPU.
3408 *
3409 * Caution: this function does not check that the caller has disabled
3410 * preemption, thus the result might have a time-of-check-to-time-of-use
3411 * race. The caller is responsible to use it correctly, for example:
3412 *
3413 * - from a non-preemptible section (of course)
3414 *
3415 * - from a thread that is bound to a single CPU
3416 *
3417 * - in a loop with very short iterations (e.g. a polling loop)
3418 */
3419bool single_task_running(void)
3420{
3421 return raw_rq()->nr_running == 1;
3422}
3423EXPORT_SYMBOL(single_task_running);
3424
3425unsigned long long nr_context_switches(void)
3426{
3427 int i;
3428 unsigned long long sum = 0;
3429
3430 for_each_possible_cpu(i)
3431 sum += cpu_rq(i)->nr_switches;
3432
3433 return sum;
3434}
3435
3436/*
3437 * Consumers of these two interfaces, like for example the cpuidle menu
3438 * governor, are using nonsensical data. Preferring shallow idle state selection
3439 * for a CPU that has IO-wait which might not even end up running the task when
3440 * it does become runnable.
3441 */
3442
3443unsigned long nr_iowait_cpu(int cpu)
3444{
3445 return atomic_read(&cpu_rq(cpu)->nr_iowait);
3446}
3447
3448/*
3449 * IO-wait accounting, and how its mostly bollocks (on SMP).
3450 *
3451 * The idea behind IO-wait account is to account the idle time that we could
3452 * have spend running if it were not for IO. That is, if we were to improve the
3453 * storage performance, we'd have a proportional reduction in IO-wait time.
3454 *
3455 * This all works nicely on UP, where, when a task blocks on IO, we account
3456 * idle time as IO-wait, because if the storage were faster, it could've been
3457 * running and we'd not be idle.
3458 *
3459 * This has been extended to SMP, by doing the same for each CPU. This however
3460 * is broken.
3461 *
3462 * Imagine for instance the case where two tasks block on one CPU, only the one
3463 * CPU will have IO-wait accounted, while the other has regular idle. Even
3464 * though, if the storage were faster, both could've ran at the same time,
3465 * utilising both CPUs.
3466 *
3467 * This means, that when looking globally, the current IO-wait accounting on
3468 * SMP is a lower bound, by reason of under accounting.
3469 *
3470 * Worse, since the numbers are provided per CPU, they are sometimes
3471 * interpreted per CPU, and that is nonsensical. A blocked task isn't strictly
3472 * associated with any one particular CPU, it can wake to another CPU than it
3473 * blocked on. This means the per CPU IO-wait number is meaningless.
3474 *
3475 * Task CPU affinities can make all that even more 'interesting'.
3476 */
3477
3478unsigned long nr_iowait(void)
3479{
3480 unsigned long i, sum = 0;
3481
3482 for_each_possible_cpu(i)
3483 sum += nr_iowait_cpu(i);
3484
3485 return sum;
3486}
3487
3488#ifdef CONFIG_SMP
3489
3490/*
3491 * sched_exec - execve() is a valuable balancing opportunity, because at
3492 * this point the task has the smallest effective memory and cache footprint.
3493 */
3494void sched_exec(void)
3495{
3496 struct task_struct *p = current;
3497 unsigned long flags;
3498 int dest_cpu;
3499
3500 raw_spin_lock_irqsave(&p->pi_lock, flags);
3501 dest_cpu = p->sched_class->select_task_rq(p, task_cpu(p), SD_BALANCE_EXEC, 0);
3502 if (dest_cpu == smp_processor_id())
3503 goto unlock;
3504
3505 if (likely(cpu_active(dest_cpu))) {
3506 struct migration_arg arg = { p, dest_cpu };
3507
3508 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
3509 stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg);
3510 return;
3511 }
3512unlock:
3513 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
3514}
3515
3516#endif
3517
3518DEFINE_PER_CPU(struct kernel_stat, kstat);
3519DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat);
3520
3521EXPORT_PER_CPU_SYMBOL(kstat);
3522EXPORT_PER_CPU_SYMBOL(kernel_cpustat);
3523
3524/*
3525 * The function fair_sched_class.update_curr accesses the struct curr
3526 * and its field curr->exec_start; when called from task_sched_runtime(),
3527 * we observe a high rate of cache misses in practice.
3528 * Prefetching this data results in improved performance.
3529 */
3530static inline void prefetch_curr_exec_start(struct task_struct *p)
3531{
3532#ifdef CONFIG_FAIR_GROUP_SCHED
3533 struct sched_entity *curr = (&p->se)->cfs_rq->curr;
3534#else
3535 struct sched_entity *curr = (&task_rq(p)->cfs)->curr;
3536#endif
3537 prefetch(curr);
3538 prefetch(&curr->exec_start);
3539}
3540
3541/*
3542 * Return accounted runtime for the task.
3543 * In case the task is currently running, return the runtime plus current's
3544 * pending runtime that have not been accounted yet.
3545 */
3546unsigned long long task_sched_runtime(struct task_struct *p)
3547{
3548 struct rq_flags rf;
3549 struct rq *rq;
3550 u64 ns;
3551
3552#if defined(CONFIG_64BIT) && defined(CONFIG_SMP)
3553 /*
3554 * 64-bit doesn't need locks to atomically read a 64-bit value.
3555 * So we have a optimization chance when the task's delta_exec is 0.
3556 * Reading ->on_cpu is racy, but this is ok.
3557 *
3558 * If we race with it leaving CPU, we'll take a lock. So we're correct.
3559 * If we race with it entering CPU, unaccounted time is 0. This is
3560 * indistinguishable from the read occurring a few cycles earlier.
3561 * If we see ->on_cpu without ->on_rq, the task is leaving, and has
3562 * been accounted, so we're correct here as well.
3563 */
3564 if (!p->on_cpu || !task_on_rq_queued(p))
3565 return p->se.sum_exec_runtime;
3566#endif
3567
3568 rq = task_rq_lock(p, &rf);
3569 /*
3570 * Must be ->curr _and_ ->on_rq. If dequeued, we would
3571 * project cycles that may never be accounted to this
3572 * thread, breaking clock_gettime().
3573 */
3574 if (task_current(rq, p) && task_on_rq_queued(p)) {
3575 prefetch_curr_exec_start(p);
3576 update_rq_clock(rq);
3577 p->sched_class->update_curr(rq);
3578 }
3579 ns = p->se.sum_exec_runtime;
3580 task_rq_unlock(rq, p, &rf);
3581
3582 return ns;
3583}
3584
3585/*
3586 * This function gets called by the timer code, with HZ frequency.
3587 * We call it with interrupts disabled.
3588 */
3589void scheduler_tick(void)
3590{
3591 int cpu = smp_processor_id();
3592 struct rq *rq = cpu_rq(cpu);
3593 struct task_struct *curr = rq->curr;
3594 struct rq_flags rf;
3595
3596 sched_clock_tick();
3597
3598 rq_lock(rq, &rf);
3599
3600 update_rq_clock(rq);
3601 curr->sched_class->task_tick(rq, curr, 0);
3602 calc_global_load_tick(rq);
3603 psi_task_tick(rq);
3604
3605 rq_unlock(rq, &rf);
3606
3607 perf_event_task_tick();
3608
3609#ifdef CONFIG_SMP
3610 rq->idle_balance = idle_cpu(cpu);
3611 trigger_load_balance(rq);
3612#endif
3613}
3614
3615#ifdef CONFIG_NO_HZ_FULL
3616
3617struct tick_work {
3618 int cpu;
3619 atomic_t state;
3620 struct delayed_work work;
3621};
3622/* Values for ->state, see diagram below. */
3623#define TICK_SCHED_REMOTE_OFFLINE 0
3624#define TICK_SCHED_REMOTE_OFFLINING 1
3625#define TICK_SCHED_REMOTE_RUNNING 2
3626
3627/*
3628 * State diagram for ->state:
3629 *
3630 *
3631 * TICK_SCHED_REMOTE_OFFLINE
3632 * | ^
3633 * | |
3634 * | | sched_tick_remote()
3635 * | |
3636 * | |
3637 * +--TICK_SCHED_REMOTE_OFFLINING
3638 * | ^
3639 * | |
3640 * sched_tick_start() | | sched_tick_stop()
3641 * | |
3642 * V |
3643 * TICK_SCHED_REMOTE_RUNNING
3644 *
3645 *
3646 * Other transitions get WARN_ON_ONCE(), except that sched_tick_remote()
3647 * and sched_tick_start() are happy to leave the state in RUNNING.
3648 */
3649
3650static struct tick_work __percpu *tick_work_cpu;
3651
3652static void sched_tick_remote(struct work_struct *work)
3653{
3654 struct delayed_work *dwork = to_delayed_work(work);
3655 struct tick_work *twork = container_of(dwork, struct tick_work, work);
3656 int cpu = twork->cpu;
3657 struct rq *rq = cpu_rq(cpu);
3658 struct task_struct *curr;
3659 struct rq_flags rf;
3660 u64 delta;
3661 int os;
3662
3663 /*
3664 * Handle the tick only if it appears the remote CPU is running in full
3665 * dynticks mode. The check is racy by nature, but missing a tick or
3666 * having one too much is no big deal because the scheduler tick updates
3667 * statistics and checks timeslices in a time-independent way, regardless
3668 * of when exactly it is running.
3669 */
3670 if (idle_cpu(cpu) || !tick_nohz_tick_stopped_cpu(cpu))
3671 goto out_requeue;
3672
3673 rq_lock_irq(rq, &rf);
3674 curr = rq->curr;
3675 if (is_idle_task(curr) || cpu_is_offline(cpu))
3676 goto out_unlock;
3677
3678 update_rq_clock(rq);
3679 delta = rq_clock_task(rq) - curr->se.exec_start;
3680
3681 /*
3682 * Make sure the next tick runs within a reasonable
3683 * amount of time.
3684 */
3685 WARN_ON_ONCE(delta > (u64)NSEC_PER_SEC * 3);
3686 curr->sched_class->task_tick(rq, curr, 0);
3687
3688out_unlock:
3689 rq_unlock_irq(rq, &rf);
3690
3691out_requeue:
3692 /*
3693 * Run the remote tick once per second (1Hz). This arbitrary
3694 * frequency is large enough to avoid overload but short enough
3695 * to keep scheduler internal stats reasonably up to date. But
3696 * first update state to reflect hotplug activity if required.
3697 */
3698 os = atomic_fetch_add_unless(&twork->state, -1, TICK_SCHED_REMOTE_RUNNING);
3699 WARN_ON_ONCE(os == TICK_SCHED_REMOTE_OFFLINE);
3700 if (os == TICK_SCHED_REMOTE_RUNNING)
3701 queue_delayed_work(system_unbound_wq, dwork, HZ);
3702}
3703
3704static void sched_tick_start(int cpu)
3705{
3706 int os;
3707 struct tick_work *twork;
3708
3709 if (housekeeping_cpu(cpu, HK_FLAG_TICK))
3710 return;
3711
3712 WARN_ON_ONCE(!tick_work_cpu);
3713
3714 twork = per_cpu_ptr(tick_work_cpu, cpu);
3715 os = atomic_xchg(&twork->state, TICK_SCHED_REMOTE_RUNNING);
3716 WARN_ON_ONCE(os == TICK_SCHED_REMOTE_RUNNING);
3717 if (os == TICK_SCHED_REMOTE_OFFLINE) {
3718 twork->cpu = cpu;
3719 INIT_DELAYED_WORK(&twork->work, sched_tick_remote);
3720 queue_delayed_work(system_unbound_wq, &twork->work, HZ);
3721 }
3722}
3723
3724#ifdef CONFIG_HOTPLUG_CPU
3725static void sched_tick_stop(int cpu)
3726{
3727 struct tick_work *twork;
3728 int os;
3729
3730 if (housekeeping_cpu(cpu, HK_FLAG_TICK))
3731 return;
3732
3733 WARN_ON_ONCE(!tick_work_cpu);
3734
3735 twork = per_cpu_ptr(tick_work_cpu, cpu);
3736 /* There cannot be competing actions, but don't rely on stop-machine. */
3737 os = atomic_xchg(&twork->state, TICK_SCHED_REMOTE_OFFLINING);
3738 WARN_ON_ONCE(os != TICK_SCHED_REMOTE_RUNNING);
3739 /* Don't cancel, as this would mess up the state machine. */
3740}
3741#endif /* CONFIG_HOTPLUG_CPU */
3742
3743int __init sched_tick_offload_init(void)
3744{
3745 tick_work_cpu = alloc_percpu(struct tick_work);
3746 BUG_ON(!tick_work_cpu);
3747 return 0;
3748}
3749
3750#else /* !CONFIG_NO_HZ_FULL */
3751static inline void sched_tick_start(int cpu) { }
3752static inline void sched_tick_stop(int cpu) { }
3753#endif
3754
3755#if defined(CONFIG_PREEMPTION) && (defined(CONFIG_DEBUG_PREEMPT) || \
3756 defined(CONFIG_TRACE_PREEMPT_TOGGLE))
3757/*
3758 * If the value passed in is equal to the current preempt count
3759 * then we just disabled preemption. Start timing the latency.
3760 */
3761static inline void preempt_latency_start(int val)
3762{
3763 if (preempt_count() == val) {
3764 unsigned long ip = get_lock_parent_ip();
3765#ifdef CONFIG_DEBUG_PREEMPT
3766 current->preempt_disable_ip = ip;
3767#endif
3768 trace_preempt_off(CALLER_ADDR0, ip);
3769 }
3770}
3771
3772void preempt_count_add(int val)
3773{
3774#ifdef CONFIG_DEBUG_PREEMPT
3775 /*
3776 * Underflow?
3777 */
3778 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
3779 return;
3780#endif
3781 __preempt_count_add(val);
3782#ifdef CONFIG_DEBUG_PREEMPT
3783 /*
3784 * Spinlock count overflowing soon?
3785 */
3786 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
3787 PREEMPT_MASK - 10);
3788#endif
3789 preempt_latency_start(val);
3790}
3791EXPORT_SYMBOL(preempt_count_add);
3792NOKPROBE_SYMBOL(preempt_count_add);
3793
3794/*
3795 * If the value passed in equals to the current preempt count
3796 * then we just enabled preemption. Stop timing the latency.
3797 */
3798static inline void preempt_latency_stop(int val)
3799{
3800 if (preempt_count() == val)
3801 trace_preempt_on(CALLER_ADDR0, get_lock_parent_ip());
3802}
3803
3804void preempt_count_sub(int val)
3805{
3806#ifdef CONFIG_DEBUG_PREEMPT
3807 /*
3808 * Underflow?
3809 */
3810 if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
3811 return;
3812 /*
3813 * Is the spinlock portion underflowing?
3814 */
3815 if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
3816 !(preempt_count() & PREEMPT_MASK)))
3817 return;
3818#endif
3819
3820 preempt_latency_stop(val);
3821 __preempt_count_sub(val);
3822}
3823EXPORT_SYMBOL(preempt_count_sub);
3824NOKPROBE_SYMBOL(preempt_count_sub);
3825
3826#else
3827static inline void preempt_latency_start(int val) { }
3828static inline void preempt_latency_stop(int val) { }
3829#endif
3830
3831static inline unsigned long get_preempt_disable_ip(struct task_struct *p)
3832{
3833#ifdef CONFIG_DEBUG_PREEMPT
3834 return p->preempt_disable_ip;
3835#else
3836 return 0;
3837#endif
3838}
3839
3840/*
3841 * Print scheduling while atomic bug:
3842 */
3843static noinline void __schedule_bug(struct task_struct *prev)
3844{
3845 /* Save this before calling printk(), since that will clobber it */
3846 unsigned long preempt_disable_ip = get_preempt_disable_ip(current);
3847
3848 if (oops_in_progress)
3849 return;
3850
3851 printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
3852 prev->comm, prev->pid, preempt_count());
3853
3854 debug_show_held_locks(prev);
3855 print_modules();
3856 if (irqs_disabled())
3857 print_irqtrace_events(prev);
3858 if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)
3859 && in_atomic_preempt_off()) {
3860 pr_err("Preemption disabled at:");
3861 print_ip_sym(preempt_disable_ip);
3862 pr_cont("\n");
3863 }
3864 if (panic_on_warn)
3865 panic("scheduling while atomic\n");
3866
3867 dump_stack();
3868 add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
3869}
3870
3871/*
3872 * Various schedule()-time debugging checks and statistics:
3873 */
3874static inline void schedule_debug(struct task_struct *prev, bool preempt)
3875{
3876#ifdef CONFIG_SCHED_STACK_END_CHECK
3877 if (task_stack_end_corrupted(prev))
3878 panic("corrupted stack end detected inside scheduler\n");
3879#endif
3880
3881#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
3882 if (!preempt && prev->state && prev->non_block_count) {
3883 printk(KERN_ERR "BUG: scheduling in a non-blocking section: %s/%d/%i\n",
3884 prev->comm, prev->pid, prev->non_block_count);
3885 dump_stack();
3886 add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
3887 }
3888#endif
3889
3890 if (unlikely(in_atomic_preempt_off())) {
3891 __schedule_bug(prev);
3892 preempt_count_set(PREEMPT_DISABLED);
3893 }
3894 rcu_sleep_check();
3895
3896 profile_hit(SCHED_PROFILING, __builtin_return_address(0));
3897
3898 schedstat_inc(this_rq()->sched_count);
3899}
3900
3901/*
3902 * Pick up the highest-prio task:
3903 */
3904static inline struct task_struct *
3905pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
3906{
3907 const struct sched_class *class;
3908 struct task_struct *p;
3909
3910 /*
3911 * Optimization: we know that if all tasks are in the fair class we can
3912 * call that function directly, but only if the @prev task wasn't of a
3913 * higher scheduling class, because otherwise those loose the
3914 * opportunity to pull in more work from other CPUs.
3915 */
3916 if (likely((prev->sched_class == &idle_sched_class ||
3917 prev->sched_class == &fair_sched_class) &&
3918 rq->nr_running == rq->cfs.h_nr_running)) {
3919
3920 p = fair_sched_class.pick_next_task(rq, prev, rf);
3921 if (unlikely(p == RETRY_TASK))
3922 goto restart;
3923
3924 /* Assumes fair_sched_class->next == idle_sched_class */
3925 if (unlikely(!p))
3926 p = idle_sched_class.pick_next_task(rq, prev, rf);
3927
3928 return p;
3929 }
3930
3931restart:
3932#ifdef CONFIG_SMP
3933 /*
3934 * We must do the balancing pass before put_next_task(), such
3935 * that when we release the rq->lock the task is in the same
3936 * state as before we took rq->lock.
3937 *
3938 * We can terminate the balance pass as soon as we know there is
3939 * a runnable task of @class priority or higher.
3940 */
3941 for_class_range(class, prev->sched_class, &idle_sched_class) {
3942 if (class->balance(rq, prev, rf))
3943 break;
3944 }
3945#endif
3946
3947 put_prev_task(rq, prev);
3948
3949 for_each_class(class) {
3950 p = class->pick_next_task(rq, NULL, NULL);
3951 if (p)
3952 return p;
3953 }
3954
3955 /* The idle class should always have a runnable task: */
3956 BUG();
3957}
3958
3959/*
3960 * __schedule() is the main scheduler function.
3961 *
3962 * The main means of driving the scheduler and thus entering this function are:
3963 *
3964 * 1. Explicit blocking: mutex, semaphore, waitqueue, etc.
3965 *
3966 * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return
3967 * paths. For example, see arch/x86/entry_64.S.
3968 *
3969 * To drive preemption between tasks, the scheduler sets the flag in timer
3970 * interrupt handler scheduler_tick().
3971 *
3972 * 3. Wakeups don't really cause entry into schedule(). They add a
3973 * task to the run-queue and that's it.
3974 *
3975 * Now, if the new task added to the run-queue preempts the current
3976 * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets
3977 * called on the nearest possible occasion:
3978 *
3979 * - If the kernel is preemptible (CONFIG_PREEMPTION=y):
3980 *
3981 * - in syscall or exception context, at the next outmost
3982 * preempt_enable(). (this might be as soon as the wake_up()'s
3983 * spin_unlock()!)
3984 *
3985 * - in IRQ context, return from interrupt-handler to
3986 * preemptible context
3987 *
3988 * - If the kernel is not preemptible (CONFIG_PREEMPTION is not set)
3989 * then at the next:
3990 *
3991 * - cond_resched() call
3992 * - explicit schedule() call
3993 * - return from syscall or exception to user-space
3994 * - return from interrupt-handler to user-space
3995 *
3996 * WARNING: must be called with preemption disabled!
3997 */
3998static void __sched notrace __schedule(bool preempt)
3999{
4000 struct task_struct *prev, *next;
4001 unsigned long *switch_count;
4002 struct rq_flags rf;
4003 struct rq *rq;
4004 int cpu;
4005
4006 cpu = smp_processor_id();
4007 rq = cpu_rq(cpu);
4008 prev = rq->curr;
4009
4010 schedule_debug(prev, preempt);
4011
4012 if (sched_feat(HRTICK))
4013 hrtick_clear(rq);
4014
4015 local_irq_disable();
4016 rcu_note_context_switch(preempt);
4017
4018 /*
4019 * Make sure that signal_pending_state()->signal_pending() below
4020 * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE)
4021 * done by the caller to avoid the race with signal_wake_up().
4022 *
4023 * The membarrier system call requires a full memory barrier
4024 * after coming from user-space, before storing to rq->curr.
4025 */
4026 rq_lock(rq, &rf);
4027 smp_mb__after_spinlock();
4028
4029 /* Promote REQ to ACT */
4030 rq->clock_update_flags <<= 1;
4031 update_rq_clock(rq);
4032
4033 switch_count = &prev->nivcsw;
4034 if (!preempt && prev->state) {
4035 if (signal_pending_state(prev->state, prev)) {
4036 prev->state = TASK_RUNNING;
4037 } else {
4038 deactivate_task(rq, prev, DEQUEUE_SLEEP | DEQUEUE_NOCLOCK);
4039
4040 if (prev->in_iowait) {
4041 atomic_inc(&rq->nr_iowait);
4042 delayacct_blkio_start();
4043 }
4044 }
4045 switch_count = &prev->nvcsw;
4046 }
4047
4048 next = pick_next_task(rq, prev, &rf);
4049 clear_tsk_need_resched(prev);
4050 clear_preempt_need_resched();
4051
4052 if (likely(prev != next)) {
4053 rq->nr_switches++;
4054 /*
4055 * RCU users of rcu_dereference(rq->curr) may not see
4056 * changes to task_struct made by pick_next_task().
4057 */
4058 RCU_INIT_POINTER(rq->curr, next);
4059 /*
4060 * The membarrier system call requires each architecture
4061 * to have a full memory barrier after updating
4062 * rq->curr, before returning to user-space.
4063 *
4064 * Here are the schemes providing that barrier on the
4065 * various architectures:
4066 * - mm ? switch_mm() : mmdrop() for x86, s390, sparc, PowerPC.
4067 * switch_mm() rely on membarrier_arch_switch_mm() on PowerPC.
4068 * - finish_lock_switch() for weakly-ordered
4069 * architectures where spin_unlock is a full barrier,
4070 * - switch_to() for arm64 (weakly-ordered, spin_unlock
4071 * is a RELEASE barrier),
4072 */
4073 ++*switch_count;
4074
4075 trace_sched_switch(preempt, prev, next);
4076
4077 /* Also unlocks the rq: */
4078 rq = context_switch(rq, prev, next, &rf);
4079 } else {
4080 rq->clock_update_flags &= ~(RQCF_ACT_SKIP|RQCF_REQ_SKIP);
4081 rq_unlock_irq(rq, &rf);
4082 }
4083
4084 balance_callback(rq);
4085}
4086
4087void __noreturn do_task_dead(void)
4088{
4089 /* Causes final put_task_struct in finish_task_switch(): */
4090 set_special_state(TASK_DEAD);
4091
4092 /* Tell freezer to ignore us: */
4093 current->flags |= PF_NOFREEZE;
4094
4095 __schedule(false);
4096 BUG();
4097
4098 /* Avoid "noreturn function does return" - but don't continue if BUG() is a NOP: */
4099 for (;;)
4100 cpu_relax();
4101}
4102
4103static inline void sched_submit_work(struct task_struct *tsk)
4104{
4105 if (!tsk->state)
4106 return;
4107
4108 /*
4109 * If a worker went to sleep, notify and ask workqueue whether
4110 * it wants to wake up a task to maintain concurrency.
4111 * As this function is called inside the schedule() context,
4112 * we disable preemption to avoid it calling schedule() again
4113 * in the possible wakeup of a kworker.
4114 */
4115 if (tsk->flags & PF_WQ_WORKER) {
4116 preempt_disable();
4117 wq_worker_sleeping(tsk);
4118 preempt_enable_no_resched();
4119 }
4120
4121 if (tsk_is_pi_blocked(tsk))
4122 return;
4123
4124 /*
4125 * If we are going to sleep and we have plugged IO queued,
4126 * make sure to submit it to avoid deadlocks.
4127 */
4128 if (blk_needs_flush_plug(tsk))
4129 blk_schedule_flush_plug(tsk);
4130}
4131
4132static void sched_update_worker(struct task_struct *tsk)
4133{
4134 if (tsk->flags & PF_WQ_WORKER)
4135 wq_worker_running(tsk);
4136}
4137
4138asmlinkage __visible void __sched schedule(void)
4139{
4140 struct task_struct *tsk = current;
4141
4142 sched_submit_work(tsk);
4143 do {
4144 preempt_disable();
4145 __schedule(false);
4146 sched_preempt_enable_no_resched();
4147 } while (need_resched());
4148 sched_update_worker(tsk);
4149}
4150EXPORT_SYMBOL(schedule);
4151
4152/*
4153 * synchronize_rcu_tasks() makes sure that no task is stuck in preempted
4154 * state (have scheduled out non-voluntarily) by making sure that all
4155 * tasks have either left the run queue or have gone into user space.
4156 * As idle tasks do not do either, they must not ever be preempted
4157 * (schedule out non-voluntarily).
4158 *
4159 * schedule_idle() is similar to schedule_preempt_disable() except that it
4160 * never enables preemption because it does not call sched_submit_work().
4161 */
4162void __sched schedule_idle(void)
4163{
4164 /*
4165 * As this skips calling sched_submit_work(), which the idle task does
4166 * regardless because that function is a nop when the task is in a
4167 * TASK_RUNNING state, make sure this isn't used someplace that the
4168 * current task can be in any other state. Note, idle is always in the
4169 * TASK_RUNNING state.
4170 */
4171 WARN_ON_ONCE(current->state);
4172 do {
4173 __schedule(false);
4174 } while (need_resched());
4175}
4176
4177#ifdef CONFIG_CONTEXT_TRACKING
4178asmlinkage __visible void __sched schedule_user(void)
4179{
4180 /*
4181 * If we come here after a random call to set_need_resched(),
4182 * or we have been woken up remotely but the IPI has not yet arrived,
4183 * we haven't yet exited the RCU idle mode. Do it here manually until
4184 * we find a better solution.
4185 *
4186 * NB: There are buggy callers of this function. Ideally we
4187 * should warn if prev_state != CONTEXT_USER, but that will trigger
4188 * too frequently to make sense yet.
4189 */
4190 enum ctx_state prev_state = exception_enter();
4191 schedule();
4192 exception_exit(prev_state);
4193}
4194#endif
4195
4196/**
4197 * schedule_preempt_disabled - called with preemption disabled
4198 *
4199 * Returns with preemption disabled. Note: preempt_count must be 1
4200 */
4201void __sched schedule_preempt_disabled(void)
4202{
4203 sched_preempt_enable_no_resched();
4204 schedule();
4205 preempt_disable();
4206}
4207
4208static void __sched notrace preempt_schedule_common(void)
4209{
4210 do {
4211 /*
4212 * Because the function tracer can trace preempt_count_sub()
4213 * and it also uses preempt_enable/disable_notrace(), if
4214 * NEED_RESCHED is set, the preempt_enable_notrace() called
4215 * by the function tracer will call this function again and
4216 * cause infinite recursion.
4217 *
4218 * Preemption must be disabled here before the function
4219 * tracer can trace. Break up preempt_disable() into two
4220 * calls. One to disable preemption without fear of being
4221 * traced. The other to still record the preemption latency,
4222 * which can also be traced by the function tracer.
4223 */
4224 preempt_disable_notrace();
4225 preempt_latency_start(1);
4226 __schedule(true);
4227 preempt_latency_stop(1);
4228 preempt_enable_no_resched_notrace();
4229
4230 /*
4231 * Check again in case we missed a preemption opportunity
4232 * between schedule and now.
4233 */
4234 } while (need_resched());
4235}
4236
4237#ifdef CONFIG_PREEMPTION
4238/*
4239 * This is the entry point to schedule() from in-kernel preemption
4240 * off of preempt_enable.
4241 */
4242asmlinkage __visible void __sched notrace preempt_schedule(void)
4243{
4244 /*
4245 * If there is a non-zero preempt_count or interrupts are disabled,
4246 * we do not want to preempt the current task. Just return..
4247 */
4248 if (likely(!preemptible()))
4249 return;
4250
4251 preempt_schedule_common();
4252}
4253NOKPROBE_SYMBOL(preempt_schedule);
4254EXPORT_SYMBOL(preempt_schedule);
4255
4256/**
4257 * preempt_schedule_notrace - preempt_schedule called by tracing
4258 *
4259 * The tracing infrastructure uses preempt_enable_notrace to prevent
4260 * recursion and tracing preempt enabling caused by the tracing
4261 * infrastructure itself. But as tracing can happen in areas coming
4262 * from userspace or just about to enter userspace, a preempt enable
4263 * can occur before user_exit() is called. This will cause the scheduler
4264 * to be called when the system is still in usermode.
4265 *
4266 * To prevent this, the preempt_enable_notrace will use this function
4267 * instead of preempt_schedule() to exit user context if needed before
4268 * calling the scheduler.
4269 */
4270asmlinkage __visible void __sched notrace preempt_schedule_notrace(void)
4271{
4272 enum ctx_state prev_ctx;
4273
4274 if (likely(!preemptible()))
4275 return;
4276
4277 do {
4278 /*
4279 * Because the function tracer can trace preempt_count_sub()
4280 * and it also uses preempt_enable/disable_notrace(), if
4281 * NEED_RESCHED is set, the preempt_enable_notrace() called
4282 * by the function tracer will call this function again and
4283 * cause infinite recursion.
4284 *
4285 * Preemption must be disabled here before the function
4286 * tracer can trace. Break up preempt_disable() into two
4287 * calls. One to disable preemption without fear of being
4288 * traced. The other to still record the preemption latency,
4289 * which can also be traced by the function tracer.
4290 */
4291 preempt_disable_notrace();
4292 preempt_latency_start(1);
4293 /*
4294 * Needs preempt disabled in case user_exit() is traced
4295 * and the tracer calls preempt_enable_notrace() causing
4296 * an infinite recursion.
4297 */
4298 prev_ctx = exception_enter();
4299 __schedule(true);
4300 exception_exit(prev_ctx);
4301
4302 preempt_latency_stop(1);
4303 preempt_enable_no_resched_notrace();
4304 } while (need_resched());
4305}
4306EXPORT_SYMBOL_GPL(preempt_schedule_notrace);
4307
4308#endif /* CONFIG_PREEMPTION */
4309
4310/*
4311 * This is the entry point to schedule() from kernel preemption
4312 * off of irq context.
4313 * Note, that this is called and return with irqs disabled. This will
4314 * protect us against recursive calling from irq.
4315 */
4316asmlinkage __visible void __sched preempt_schedule_irq(void)
4317{
4318 enum ctx_state prev_state;
4319
4320 /* Catch callers which need to be fixed */
4321 BUG_ON(preempt_count() || !irqs_disabled());
4322
4323 prev_state = exception_enter();
4324
4325 do {
4326 preempt_disable();
4327 local_irq_enable();
4328 __schedule(true);
4329 local_irq_disable();
4330 sched_preempt_enable_no_resched();
4331 } while (need_resched());
4332
4333 exception_exit(prev_state);
4334}
4335
4336int default_wake_function(wait_queue_entry_t *curr, unsigned mode, int wake_flags,
4337 void *key)
4338{
4339 return try_to_wake_up(curr->private, mode, wake_flags);
4340}
4341EXPORT_SYMBOL(default_wake_function);
4342
4343#ifdef CONFIG_RT_MUTEXES
4344
4345static inline int __rt_effective_prio(struct task_struct *pi_task, int prio)
4346{
4347 if (pi_task)
4348 prio = min(prio, pi_task->prio);
4349
4350 return prio;
4351}
4352
4353static inline int rt_effective_prio(struct task_struct *p, int prio)
4354{
4355 struct task_struct *pi_task = rt_mutex_get_top_task(p);
4356
4357 return __rt_effective_prio(pi_task, prio);
4358}
4359
4360/*
4361 * rt_mutex_setprio - set the current priority of a task
4362 * @p: task to boost
4363 * @pi_task: donor task
4364 *
4365 * This function changes the 'effective' priority of a task. It does
4366 * not touch ->normal_prio like __setscheduler().
4367 *
4368 * Used by the rt_mutex code to implement priority inheritance
4369 * logic. Call site only calls if the priority of the task changed.
4370 */
4371void rt_mutex_setprio(struct task_struct *p, struct task_struct *pi_task)
4372{
4373 int prio, oldprio, queued, running, queue_flag =
4374 DEQUEUE_SAVE | DEQUEUE_MOVE | DEQUEUE_NOCLOCK;
4375 const struct sched_class *prev_class;
4376 struct rq_flags rf;
4377 struct rq *rq;
4378
4379 /* XXX used to be waiter->prio, not waiter->task->prio */
4380 prio = __rt_effective_prio(pi_task, p->normal_prio);
4381
4382 /*
4383 * If nothing changed; bail early.
4384 */
4385 if (p->pi_top_task == pi_task && prio == p->prio && !dl_prio(prio))
4386 return;
4387
4388 rq = __task_rq_lock(p, &rf);
4389 update_rq_clock(rq);
4390 /*
4391 * Set under pi_lock && rq->lock, such that the value can be used under
4392 * either lock.
4393 *
4394 * Note that there is loads of tricky to make this pointer cache work
4395 * right. rt_mutex_slowunlock()+rt_mutex_postunlock() work together to
4396 * ensure a task is de-boosted (pi_task is set to NULL) before the
4397 * task is allowed to run again (and can exit). This ensures the pointer
4398 * points to a blocked task -- which guaratees the task is present.
4399 */
4400 p->pi_top_task = pi_task;
4401
4402 /*
4403 * For FIFO/RR we only need to set prio, if that matches we're done.
4404 */
4405 if (prio == p->prio && !dl_prio(prio))
4406 goto out_unlock;
4407
4408 /*
4409 * Idle task boosting is a nono in general. There is one
4410 * exception, when PREEMPT_RT and NOHZ is active:
4411 *
4412 * The idle task calls get_next_timer_interrupt() and holds
4413 * the timer wheel base->lock on the CPU and another CPU wants
4414 * to access the timer (probably to cancel it). We can safely
4415 * ignore the boosting request, as the idle CPU runs this code
4416 * with interrupts disabled and will complete the lock
4417 * protected section without being interrupted. So there is no
4418 * real need to boost.
4419 */
4420 if (unlikely(p == rq->idle)) {
4421 WARN_ON(p != rq->curr);
4422 WARN_ON(p->pi_blocked_on);
4423 goto out_unlock;
4424 }
4425
4426 trace_sched_pi_setprio(p, pi_task);
4427 oldprio = p->prio;
4428
4429 if (oldprio == prio)
4430 queue_flag &= ~DEQUEUE_MOVE;
4431
4432 prev_class = p->sched_class;
4433 queued = task_on_rq_queued(p);
4434 running = task_current(rq, p);
4435 if (queued)
4436 dequeue_task(rq, p, queue_flag);
4437 if (running)
4438 put_prev_task(rq, p);
4439
4440 /*
4441 * Boosting condition are:
4442 * 1. -rt task is running and holds mutex A
4443 * --> -dl task blocks on mutex A
4444 *
4445 * 2. -dl task is running and holds mutex A
4446 * --> -dl task blocks on mutex A and could preempt the
4447 * running task
4448 */
4449 if (dl_prio(prio)) {
4450 if (!dl_prio(p->normal_prio) ||
4451 (pi_task && dl_entity_preempt(&pi_task->dl, &p->dl))) {
4452 p->dl.dl_boosted = 1;
4453 queue_flag |= ENQUEUE_REPLENISH;
4454 } else
4455 p->dl.dl_boosted = 0;
4456 p->sched_class = &dl_sched_class;
4457 } else if (rt_prio(prio)) {
4458 if (dl_prio(oldprio))
4459 p->dl.dl_boosted = 0;
4460 if (oldprio < prio)
4461 queue_flag |= ENQUEUE_HEAD;
4462 p->sched_class = &rt_sched_class;
4463 } else {
4464 if (dl_prio(oldprio))
4465 p->dl.dl_boosted = 0;
4466 if (rt_prio(oldprio))
4467 p->rt.timeout = 0;
4468 p->sched_class = &fair_sched_class;
4469 }
4470
4471 p->prio = prio;
4472
4473 if (queued)
4474 enqueue_task(rq, p, queue_flag);
4475 if (running)
4476 set_next_task(rq, p);
4477
4478 check_class_changed(rq, p, prev_class, oldprio);
4479out_unlock:
4480 /* Avoid rq from going away on us: */
4481 preempt_disable();
4482 __task_rq_unlock(rq, &rf);
4483
4484 balance_callback(rq);
4485 preempt_enable();
4486}
4487#else
4488static inline int rt_effective_prio(struct task_struct *p, int prio)
4489{
4490 return prio;
4491}
4492#endif
4493
4494void set_user_nice(struct task_struct *p, long nice)
4495{
4496 bool queued, running;
4497 int old_prio, delta;
4498 struct rq_flags rf;
4499 struct rq *rq;
4500
4501 if (task_nice(p) == nice || nice < MIN_NICE || nice > MAX_NICE)
4502 return;
4503 /*
4504 * We have to be careful, if called from sys_setpriority(),
4505 * the task might be in the middle of scheduling on another CPU.
4506 */
4507 rq = task_rq_lock(p, &rf);
4508 update_rq_clock(rq);
4509
4510 /*
4511 * The RT priorities are set via sched_setscheduler(), but we still
4512 * allow the 'normal' nice value to be set - but as expected
4513 * it wont have any effect on scheduling until the task is
4514 * SCHED_DEADLINE, SCHED_FIFO or SCHED_RR:
4515 */
4516 if (task_has_dl_policy(p) || task_has_rt_policy(p)) {
4517 p->static_prio = NICE_TO_PRIO(nice);
4518 goto out_unlock;
4519 }
4520 queued = task_on_rq_queued(p);
4521 running = task_current(rq, p);
4522 if (queued)
4523 dequeue_task(rq, p, DEQUEUE_SAVE | DEQUEUE_NOCLOCK);
4524 if (running)
4525 put_prev_task(rq, p);
4526
4527 p->static_prio = NICE_TO_PRIO(nice);
4528 set_load_weight(p, true);
4529 old_prio = p->prio;
4530 p->prio = effective_prio(p);
4531 delta = p->prio - old_prio;
4532
4533 if (queued) {
4534 enqueue_task(rq, p, ENQUEUE_RESTORE | ENQUEUE_NOCLOCK);
4535 /*
4536 * If the task increased its priority or is running and
4537 * lowered its priority, then reschedule its CPU:
4538 */
4539 if (delta < 0 || (delta > 0 && task_running(rq, p)))
4540 resched_curr(rq);
4541 }
4542 if (running)
4543 set_next_task(rq, p);
4544out_unlock:
4545 task_rq_unlock(rq, p, &rf);
4546}
4547EXPORT_SYMBOL(set_user_nice);
4548
4549/*
4550 * can_nice - check if a task can reduce its nice value
4551 * @p: task
4552 * @nice: nice value
4553 */
4554int can_nice(const struct task_struct *p, const int nice)
4555{
4556 /* Convert nice value [19,-20] to rlimit style value [1,40]: */
4557 int nice_rlim = nice_to_rlimit(nice);
4558
4559 return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) ||
4560 capable(CAP_SYS_NICE));
4561}
4562
4563#ifdef __ARCH_WANT_SYS_NICE
4564
4565/*
4566 * sys_nice - change the priority of the current process.
4567 * @increment: priority increment
4568 *
4569 * sys_setpriority is a more generic, but much slower function that
4570 * does similar things.
4571 */
4572SYSCALL_DEFINE1(nice, int, increment)
4573{
4574 long nice, retval;
4575
4576 /*
4577 * Setpriority might change our priority at the same moment.
4578 * We don't have to worry. Conceptually one call occurs first
4579 * and we have a single winner.
4580 */
4581 increment = clamp(increment, -NICE_WIDTH, NICE_WIDTH);
4582 nice = task_nice(current) + increment;
4583
4584 nice = clamp_val(nice, MIN_NICE, MAX_NICE);
4585 if (increment < 0 && !can_nice(current, nice))
4586 return -EPERM;
4587
4588 retval = security_task_setnice(current, nice);
4589 if (retval)
4590 return retval;
4591
4592 set_user_nice(current, nice);
4593 return 0;
4594}
4595
4596#endif
4597
4598/**
4599 * task_prio - return the priority value of a given task.
4600 * @p: the task in question.
4601 *
4602 * Return: The priority value as seen by users in /proc.
4603 * RT tasks are offset by -200. Normal tasks are centered
4604 * around 0, value goes from -16 to +15.
4605 */
4606int task_prio(const struct task_struct *p)
4607{
4608 return p->prio - MAX_RT_PRIO;
4609}
4610
4611/**
4612 * idle_cpu - is a given CPU idle currently?
4613 * @cpu: the processor in question.
4614 *
4615 * Return: 1 if the CPU is currently idle. 0 otherwise.
4616 */
4617int idle_cpu(int cpu)
4618{
4619 struct rq *rq = cpu_rq(cpu);
4620
4621 if (rq->curr != rq->idle)
4622 return 0;
4623
4624 if (rq->nr_running)
4625 return 0;
4626
4627#ifdef CONFIG_SMP
4628 if (!llist_empty(&rq->wake_list))
4629 return 0;
4630#endif
4631
4632 return 1;
4633}
4634
4635/**
4636 * available_idle_cpu - is a given CPU idle for enqueuing work.
4637 * @cpu: the CPU in question.
4638 *
4639 * Return: 1 if the CPU is currently idle. 0 otherwise.
4640 */
4641int available_idle_cpu(int cpu)
4642{
4643 if (!idle_cpu(cpu))
4644 return 0;
4645
4646 if (vcpu_is_preempted(cpu))
4647 return 0;
4648
4649 return 1;
4650}
4651
4652/**
4653 * idle_task - return the idle task for a given CPU.
4654 * @cpu: the processor in question.
4655 *
4656 * Return: The idle task for the CPU @cpu.
4657 */
4658struct task_struct *idle_task(int cpu)
4659{
4660 return cpu_rq(cpu)->idle;
4661}
4662
4663/**
4664 * find_process_by_pid - find a process with a matching PID value.
4665 * @pid: the pid in question.
4666 *
4667 * The task of @pid, if found. %NULL otherwise.
4668 */
4669static struct task_struct *find_process_by_pid(pid_t pid)
4670{
4671 return pid ? find_task_by_vpid(pid) : current;
4672}
4673
4674/*
4675 * sched_setparam() passes in -1 for its policy, to let the functions
4676 * it calls know not to change it.
4677 */
4678#define SETPARAM_POLICY -1
4679
4680static void __setscheduler_params(struct task_struct *p,
4681 const struct sched_attr *attr)
4682{
4683 int policy = attr->sched_policy;
4684
4685 if (policy == SETPARAM_POLICY)
4686 policy = p->policy;
4687
4688 p->policy = policy;
4689
4690 if (dl_policy(policy))
4691 __setparam_dl(p, attr);
4692 else if (fair_policy(policy))
4693 p->static_prio = NICE_TO_PRIO(attr->sched_nice);
4694
4695 /*
4696 * __sched_setscheduler() ensures attr->sched_priority == 0 when
4697 * !rt_policy. Always setting this ensures that things like
4698 * getparam()/getattr() don't report silly values for !rt tasks.
4699 */
4700 p->rt_priority = attr->sched_priority;
4701 p->normal_prio = normal_prio(p);
4702 set_load_weight(p, true);
4703}
4704
4705/* Actually do priority change: must hold pi & rq lock. */
4706static void __setscheduler(struct rq *rq, struct task_struct *p,
4707 const struct sched_attr *attr, bool keep_boost)
4708{
4709 /*
4710 * If params can't change scheduling class changes aren't allowed
4711 * either.
4712 */
4713 if (attr->sched_flags & SCHED_FLAG_KEEP_PARAMS)
4714 return;
4715
4716 __setscheduler_params(p, attr);
4717
4718 /*
4719 * Keep a potential priority boosting if called from
4720 * sched_setscheduler().
4721 */
4722 p->prio = normal_prio(p);
4723 if (keep_boost)
4724 p->prio = rt_effective_prio(p, p->prio);
4725
4726 if (dl_prio(p->prio))
4727 p->sched_class = &dl_sched_class;
4728 else if (rt_prio(p->prio))
4729 p->sched_class = &rt_sched_class;
4730 else
4731 p->sched_class = &fair_sched_class;
4732}
4733
4734/*
4735 * Check the target process has a UID that matches the current process's:
4736 */
4737static bool check_same_owner(struct task_struct *p)
4738{
4739 const struct cred *cred = current_cred(), *pcred;
4740 bool match;
4741
4742 rcu_read_lock();
4743 pcred = __task_cred(p);
4744 match = (uid_eq(cred->euid, pcred->euid) ||
4745 uid_eq(cred->euid, pcred->uid));
4746 rcu_read_unlock();
4747 return match;
4748}
4749
4750static int __sched_setscheduler(struct task_struct *p,
4751 const struct sched_attr *attr,
4752 bool user, bool pi)
4753{
4754 int newprio = dl_policy(attr->sched_policy) ? MAX_DL_PRIO - 1 :
4755 MAX_RT_PRIO - 1 - attr->sched_priority;
4756 int retval, oldprio, oldpolicy = -1, queued, running;
4757 int new_effective_prio, policy = attr->sched_policy;
4758 const struct sched_class *prev_class;
4759 struct rq_flags rf;
4760 int reset_on_fork;
4761 int queue_flags = DEQUEUE_SAVE | DEQUEUE_MOVE | DEQUEUE_NOCLOCK;
4762 struct rq *rq;
4763
4764 /* The pi code expects interrupts enabled */
4765 BUG_ON(pi && in_interrupt());
4766recheck:
4767 /* Double check policy once rq lock held: */
4768 if (policy < 0) {
4769 reset_on_fork = p->sched_reset_on_fork;
4770 policy = oldpolicy = p->policy;
4771 } else {
4772 reset_on_fork = !!(attr->sched_flags & SCHED_FLAG_RESET_ON_FORK);
4773
4774 if (!valid_policy(policy))
4775 return -EINVAL;
4776 }
4777
4778 if (attr->sched_flags & ~(SCHED_FLAG_ALL | SCHED_FLAG_SUGOV))
4779 return -EINVAL;
4780
4781 /*
4782 * Valid priorities for SCHED_FIFO and SCHED_RR are
4783 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
4784 * SCHED_BATCH and SCHED_IDLE is 0.
4785 */
4786 if ((p->mm && attr->sched_priority > MAX_USER_RT_PRIO-1) ||
4787 (!p->mm && attr->sched_priority > MAX_RT_PRIO-1))
4788 return -EINVAL;
4789 if ((dl_policy(policy) && !__checkparam_dl(attr)) ||
4790 (rt_policy(policy) != (attr->sched_priority != 0)))
4791 return -EINVAL;
4792
4793 /*
4794 * Allow unprivileged RT tasks to decrease priority:
4795 */
4796 if (user && !capable(CAP_SYS_NICE)) {
4797 if (fair_policy(policy)) {
4798 if (attr->sched_nice < task_nice(p) &&
4799 !can_nice(p, attr->sched_nice))
4800 return -EPERM;
4801 }
4802
4803 if (rt_policy(policy)) {
4804 unsigned long rlim_rtprio =
4805 task_rlimit(p, RLIMIT_RTPRIO);
4806
4807 /* Can't set/change the rt policy: */
4808 if (policy != p->policy && !rlim_rtprio)
4809 return -EPERM;
4810
4811 /* Can't increase priority: */
4812 if (attr->sched_priority > p->rt_priority &&
4813 attr->sched_priority > rlim_rtprio)
4814 return -EPERM;
4815 }
4816
4817 /*
4818 * Can't set/change SCHED_DEADLINE policy at all for now
4819 * (safest behavior); in the future we would like to allow
4820 * unprivileged DL tasks to increase their relative deadline
4821 * or reduce their runtime (both ways reducing utilization)
4822 */
4823 if (dl_policy(policy))
4824 return -EPERM;
4825
4826 /*
4827 * Treat SCHED_IDLE as nice 20. Only allow a switch to
4828 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
4829 */
4830 if (task_has_idle_policy(p) && !idle_policy(policy)) {
4831 if (!can_nice(p, task_nice(p)))
4832 return -EPERM;
4833 }
4834
4835 /* Can't change other user's priorities: */
4836 if (!check_same_owner(p))
4837 return -EPERM;
4838
4839 /* Normal users shall not reset the sched_reset_on_fork flag: */
4840 if (p->sched_reset_on_fork && !reset_on_fork)
4841 return -EPERM;
4842 }
4843
4844 if (user) {
4845 if (attr->sched_flags & SCHED_FLAG_SUGOV)
4846 return -EINVAL;
4847
4848 retval = security_task_setscheduler(p);
4849 if (retval)
4850 return retval;
4851 }
4852
4853 /* Update task specific "requested" clamps */
4854 if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP) {
4855 retval = uclamp_validate(p, attr);
4856 if (retval)
4857 return retval;
4858 }
4859
4860 if (pi)
4861 cpuset_read_lock();
4862
4863 /*
4864 * Make sure no PI-waiters arrive (or leave) while we are
4865 * changing the priority of the task:
4866 *
4867 * To be able to change p->policy safely, the appropriate
4868 * runqueue lock must be held.
4869 */
4870 rq = task_rq_lock(p, &rf);
4871 update_rq_clock(rq);
4872
4873 /*
4874 * Changing the policy of the stop threads its a very bad idea:
4875 */
4876 if (p == rq->stop) {
4877 retval = -EINVAL;
4878 goto unlock;
4879 }
4880
4881 /*
4882 * If not changing anything there's no need to proceed further,
4883 * but store a possible modification of reset_on_fork.
4884 */
4885 if (unlikely(policy == p->policy)) {
4886 if (fair_policy(policy) && attr->sched_nice != task_nice(p))
4887 goto change;
4888 if (rt_policy(policy) && attr->sched_priority != p->rt_priority)
4889 goto change;
4890 if (dl_policy(policy) && dl_param_changed(p, attr))
4891 goto change;
4892 if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP)
4893 goto change;
4894
4895 p->sched_reset_on_fork = reset_on_fork;
4896 retval = 0;
4897 goto unlock;
4898 }
4899change:
4900
4901 if (user) {
4902#ifdef CONFIG_RT_GROUP_SCHED
4903 /*
4904 * Do not allow realtime tasks into groups that have no runtime
4905 * assigned.
4906 */
4907 if (rt_bandwidth_enabled() && rt_policy(policy) &&
4908 task_group(p)->rt_bandwidth.rt_runtime == 0 &&
4909 !task_group_is_autogroup(task_group(p))) {
4910 retval = -EPERM;
4911 goto unlock;
4912 }
4913#endif
4914#ifdef CONFIG_SMP
4915 if (dl_bandwidth_enabled() && dl_policy(policy) &&
4916 !(attr->sched_flags & SCHED_FLAG_SUGOV)) {
4917 cpumask_t *span = rq->rd->span;
4918
4919 /*
4920 * Don't allow tasks with an affinity mask smaller than
4921 * the entire root_domain to become SCHED_DEADLINE. We
4922 * will also fail if there's no bandwidth available.
4923 */
4924 if (!cpumask_subset(span, p->cpus_ptr) ||
4925 rq->rd->dl_bw.bw == 0) {
4926 retval = -EPERM;
4927 goto unlock;
4928 }
4929 }
4930#endif
4931 }
4932
4933 /* Re-check policy now with rq lock held: */
4934 if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
4935 policy = oldpolicy = -1;
4936 task_rq_unlock(rq, p, &rf);
4937 if (pi)
4938 cpuset_read_unlock();
4939 goto recheck;
4940 }
4941
4942 /*
4943 * If setscheduling to SCHED_DEADLINE (or changing the parameters
4944 * of a SCHED_DEADLINE task) we need to check if enough bandwidth
4945 * is available.
4946 */
4947 if ((dl_policy(policy) || dl_task(p)) && sched_dl_overflow(p, policy, attr)) {
4948 retval = -EBUSY;
4949 goto unlock;
4950 }
4951
4952 p->sched_reset_on_fork = reset_on_fork;
4953 oldprio = p->prio;
4954
4955 if (pi) {
4956 /*
4957 * Take priority boosted tasks into account. If the new
4958 * effective priority is unchanged, we just store the new
4959 * normal parameters and do not touch the scheduler class and
4960 * the runqueue. This will be done when the task deboost
4961 * itself.
4962 */
4963 new_effective_prio = rt_effective_prio(p, newprio);
4964 if (new_effective_prio == oldprio)
4965 queue_flags &= ~DEQUEUE_MOVE;
4966 }
4967
4968 queued = task_on_rq_queued(p);
4969 running = task_current(rq, p);
4970 if (queued)
4971 dequeue_task(rq, p, queue_flags);
4972 if (running)
4973 put_prev_task(rq, p);
4974
4975 prev_class = p->sched_class;
4976
4977 __setscheduler(rq, p, attr, pi);
4978 __setscheduler_uclamp(p, attr);
4979
4980 if (queued) {
4981 /*
4982 * We enqueue to tail when the priority of a task is
4983 * increased (user space view).
4984 */
4985 if (oldprio < p->prio)
4986 queue_flags |= ENQUEUE_HEAD;
4987
4988 enqueue_task(rq, p, queue_flags);
4989 }
4990 if (running)
4991 set_next_task(rq, p);
4992
4993 check_class_changed(rq, p, prev_class, oldprio);
4994
4995 /* Avoid rq from going away on us: */
4996 preempt_disable();
4997 task_rq_unlock(rq, p, &rf);
4998
4999 if (pi) {
5000 cpuset_read_unlock();
5001 rt_mutex_adjust_pi(p);
5002 }
5003
5004 /* Run balance callbacks after we've adjusted the PI chain: */
5005 balance_callback(rq);
5006 preempt_enable();
5007
5008 return 0;
5009
5010unlock:
5011 task_rq_unlock(rq, p, &rf);
5012 if (pi)
5013 cpuset_read_unlock();
5014 return retval;
5015}
5016
5017static int _sched_setscheduler(struct task_struct *p, int policy,
5018 const struct sched_param *param, bool check)
5019{
5020 struct sched_attr attr = {
5021 .sched_policy = policy,
5022 .sched_priority = param->sched_priority,
5023 .sched_nice = PRIO_TO_NICE(p->static_prio),
5024 };
5025
5026 /* Fixup the legacy SCHED_RESET_ON_FORK hack. */
5027 if ((policy != SETPARAM_POLICY) && (policy & SCHED_RESET_ON_FORK)) {
5028 attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK;
5029 policy &= ~SCHED_RESET_ON_FORK;
5030 attr.sched_policy = policy;
5031 }
5032
5033 return __sched_setscheduler(p, &attr, check, true);
5034}
5035/**
5036 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
5037 * @p: the task in question.
5038 * @policy: new policy.
5039 * @param: structure containing the new RT priority.
5040 *
5041 * Return: 0 on success. An error code otherwise.
5042 *
5043 * NOTE that the task may be already dead.
5044 */
5045int sched_setscheduler(struct task_struct *p, int policy,
5046 const struct sched_param *param)
5047{
5048 return _sched_setscheduler(p, policy, param, true);
5049}
5050EXPORT_SYMBOL_GPL(sched_setscheduler);
5051
5052int sched_setattr(struct task_struct *p, const struct sched_attr *attr)
5053{
5054 return __sched_setscheduler(p, attr, true, true);
5055}
5056EXPORT_SYMBOL_GPL(sched_setattr);
5057
5058int sched_setattr_nocheck(struct task_struct *p, const struct sched_attr *attr)
5059{
5060 return __sched_setscheduler(p, attr, false, true);
5061}
5062
5063/**
5064 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
5065 * @p: the task in question.
5066 * @policy: new policy.
5067 * @param: structure containing the new RT priority.
5068 *
5069 * Just like sched_setscheduler, only don't bother checking if the
5070 * current context has permission. For example, this is needed in
5071 * stop_machine(): we create temporary high priority worker threads,
5072 * but our caller might not have that capability.
5073 *
5074 * Return: 0 on success. An error code otherwise.
5075 */
5076int sched_setscheduler_nocheck(struct task_struct *p, int policy,
5077 const struct sched_param *param)
5078{
5079 return _sched_setscheduler(p, policy, param, false);
5080}
5081EXPORT_SYMBOL_GPL(sched_setscheduler_nocheck);
5082
5083static int
5084do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
5085{
5086 struct sched_param lparam;
5087 struct task_struct *p;
5088 int retval;
5089
5090 if (!param || pid < 0)
5091 return -EINVAL;
5092 if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
5093 return -EFAULT;
5094
5095 rcu_read_lock();
5096 retval = -ESRCH;
5097 p = find_process_by_pid(pid);
5098 if (likely(p))
5099 get_task_struct(p);
5100 rcu_read_unlock();
5101
5102 if (likely(p)) {
5103 retval = sched_setscheduler(p, policy, &lparam);
5104 put_task_struct(p);
5105 }
5106
5107 return retval;
5108}
5109
5110/*
5111 * Mimics kernel/events/core.c perf_copy_attr().
5112 */
5113static int sched_copy_attr(struct sched_attr __user *uattr, struct sched_attr *attr)
5114{
5115 u32 size;
5116 int ret;
5117
5118 /* Zero the full structure, so that a short copy will be nice: */
5119 memset(attr, 0, sizeof(*attr));
5120
5121 ret = get_user(size, &uattr->size);
5122 if (ret)
5123 return ret;
5124
5125 /* ABI compatibility quirk: */
5126 if (!size)
5127 size = SCHED_ATTR_SIZE_VER0;
5128 if (size < SCHED_ATTR_SIZE_VER0 || size > PAGE_SIZE)
5129 goto err_size;
5130
5131 ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
5132 if (ret) {
5133 if (ret == -E2BIG)
5134 goto err_size;
5135 return ret;
5136 }
5137
5138 if ((attr->sched_flags & SCHED_FLAG_UTIL_CLAMP) &&
5139 size < SCHED_ATTR_SIZE_VER1)
5140 return -EINVAL;
5141
5142 /*
5143 * XXX: Do we want to be lenient like existing syscalls; or do we want
5144 * to be strict and return an error on out-of-bounds values?
5145 */
5146 attr->sched_nice = clamp(attr->sched_nice, MIN_NICE, MAX_NICE);
5147
5148 return 0;
5149
5150err_size:
5151 put_user(sizeof(*attr), &uattr->size);
5152 return -E2BIG;
5153}
5154
5155/**
5156 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
5157 * @pid: the pid in question.
5158 * @policy: new policy.
5159 * @param: structure containing the new RT priority.
5160 *
5161 * Return: 0 on success. An error code otherwise.
5162 */
5163SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy, struct sched_param __user *, param)
5164{
5165 if (policy < 0)
5166 return -EINVAL;
5167
5168 return do_sched_setscheduler(pid, policy, param);
5169}
5170
5171/**
5172 * sys_sched_setparam - set/change the RT priority of a thread
5173 * @pid: the pid in question.
5174 * @param: structure containing the new RT priority.
5175 *
5176 * Return: 0 on success. An error code otherwise.
5177 */
5178SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param)
5179{
5180 return do_sched_setscheduler(pid, SETPARAM_POLICY, param);
5181}
5182
5183/**
5184 * sys_sched_setattr - same as above, but with extended sched_attr
5185 * @pid: the pid in question.
5186 * @uattr: structure containing the extended parameters.
5187 * @flags: for future extension.
5188 */
5189SYSCALL_DEFINE3(sched_setattr, pid_t, pid, struct sched_attr __user *, uattr,
5190 unsigned int, flags)
5191{
5192 struct sched_attr attr;
5193 struct task_struct *p;
5194 int retval;
5195
5196 if (!uattr || pid < 0 || flags)
5197 return -EINVAL;
5198
5199 retval = sched_copy_attr(uattr, &attr);
5200 if (retval)
5201 return retval;
5202
5203 if ((int)attr.sched_policy < 0)
5204 return -EINVAL;
5205 if (attr.sched_flags & SCHED_FLAG_KEEP_POLICY)
5206 attr.sched_policy = SETPARAM_POLICY;
5207
5208 rcu_read_lock();
5209 retval = -ESRCH;
5210 p = find_process_by_pid(pid);
5211 if (likely(p))
5212 get_task_struct(p);
5213 rcu_read_unlock();
5214
5215 if (likely(p)) {
5216 retval = sched_setattr(p, &attr);
5217 put_task_struct(p);
5218 }
5219
5220 return retval;
5221}
5222
5223/**
5224 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
5225 * @pid: the pid in question.
5226 *
5227 * Return: On success, the policy of the thread. Otherwise, a negative error
5228 * code.
5229 */
5230SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid)
5231{
5232 struct task_struct *p;
5233 int retval;
5234
5235 if (pid < 0)
5236 return -EINVAL;
5237
5238 retval = -ESRCH;
5239 rcu_read_lock();
5240 p = find_process_by_pid(pid);
5241 if (p) {
5242 retval = security_task_getscheduler(p);
5243 if (!retval)
5244 retval = p->policy
5245 | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0);
5246 }
5247 rcu_read_unlock();
5248 return retval;
5249}
5250
5251/**
5252 * sys_sched_getparam - get the RT priority of a thread
5253 * @pid: the pid in question.
5254 * @param: structure containing the RT priority.
5255 *
5256 * Return: On success, 0 and the RT priority is in @param. Otherwise, an error
5257 * code.
5258 */
5259SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param)
5260{
5261 struct sched_param lp = { .sched_priority = 0 };
5262 struct task_struct *p;
5263 int retval;
5264
5265 if (!param || pid < 0)
5266 return -EINVAL;
5267
5268 rcu_read_lock();
5269 p = find_process_by_pid(pid);
5270 retval = -ESRCH;
5271 if (!p)
5272 goto out_unlock;
5273
5274 retval = security_task_getscheduler(p);
5275 if (retval)
5276 goto out_unlock;
5277
5278 if (task_has_rt_policy(p))
5279 lp.sched_priority = p->rt_priority;
5280 rcu_read_unlock();
5281
5282 /*
5283 * This one might sleep, we cannot do it with a spinlock held ...
5284 */
5285 retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;
5286
5287 return retval;
5288
5289out_unlock:
5290 rcu_read_unlock();
5291 return retval;
5292}
5293
5294/*
5295 * Copy the kernel size attribute structure (which might be larger
5296 * than what user-space knows about) to user-space.
5297 *
5298 * Note that all cases are valid: user-space buffer can be larger or
5299 * smaller than the kernel-space buffer. The usual case is that both
5300 * have the same size.
5301 */
5302static int
5303sched_attr_copy_to_user(struct sched_attr __user *uattr,
5304 struct sched_attr *kattr,
5305 unsigned int usize)
5306{
5307 unsigned int ksize = sizeof(*kattr);
5308
5309 if (!access_ok(uattr, usize))
5310 return -EFAULT;
5311
5312 /*
5313 * sched_getattr() ABI forwards and backwards compatibility:
5314 *
5315 * If usize == ksize then we just copy everything to user-space and all is good.
5316 *
5317 * If usize < ksize then we only copy as much as user-space has space for,
5318 * this keeps ABI compatibility as well. We skip the rest.
5319 *
5320 * If usize > ksize then user-space is using a newer version of the ABI,
5321 * which part the kernel doesn't know about. Just ignore it - tooling can
5322 * detect the kernel's knowledge of attributes from the attr->size value
5323 * which is set to ksize in this case.
5324 */
5325 kattr->size = min(usize, ksize);
5326
5327 if (copy_to_user(uattr, kattr, kattr->size))
5328 return -EFAULT;
5329
5330 return 0;
5331}
5332
5333/**
5334 * sys_sched_getattr - similar to sched_getparam, but with sched_attr
5335 * @pid: the pid in question.
5336 * @uattr: structure containing the extended parameters.
5337 * @usize: sizeof(attr) for fwd/bwd comp.
5338 * @flags: for future extension.
5339 */
5340SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr,
5341 unsigned int, usize, unsigned int, flags)
5342{
5343 struct sched_attr kattr = { };
5344 struct task_struct *p;
5345 int retval;
5346
5347 if (!uattr || pid < 0 || usize > PAGE_SIZE ||
5348 usize < SCHED_ATTR_SIZE_VER0 || flags)
5349 return -EINVAL;
5350
5351 rcu_read_lock();
5352 p = find_process_by_pid(pid);
5353 retval = -ESRCH;
5354 if (!p)
5355 goto out_unlock;
5356
5357 retval = security_task_getscheduler(p);
5358 if (retval)
5359 goto out_unlock;
5360
5361 kattr.sched_policy = p->policy;
5362 if (p->sched_reset_on_fork)
5363 kattr.sched_flags |= SCHED_FLAG_RESET_ON_FORK;
5364 if (task_has_dl_policy(p))
5365 __getparam_dl(p, &kattr);
5366 else if (task_has_rt_policy(p))
5367 kattr.sched_priority = p->rt_priority;
5368 else
5369 kattr.sched_nice = task_nice(p);
5370
5371#ifdef CONFIG_UCLAMP_TASK
5372 kattr.sched_util_min = p->uclamp_req[UCLAMP_MIN].value;
5373 kattr.sched_util_max = p->uclamp_req[UCLAMP_MAX].value;
5374#endif
5375
5376 rcu_read_unlock();
5377
5378 return sched_attr_copy_to_user(uattr, &kattr, usize);
5379
5380out_unlock:
5381 rcu_read_unlock();
5382 return retval;
5383}
5384
5385long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
5386{
5387 cpumask_var_t cpus_allowed, new_mask;
5388 struct task_struct *p;
5389 int retval;
5390
5391 rcu_read_lock();
5392
5393 p = find_process_by_pid(pid);
5394 if (!p) {
5395 rcu_read_unlock();
5396 return -ESRCH;
5397 }
5398
5399 /* Prevent p going away */
5400 get_task_struct(p);
5401 rcu_read_unlock();
5402
5403 if (p->flags & PF_NO_SETAFFINITY) {
5404 retval = -EINVAL;
5405 goto out_put_task;
5406 }
5407 if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) {
5408 retval = -ENOMEM;
5409 goto out_put_task;
5410 }
5411 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
5412 retval = -ENOMEM;
5413 goto out_free_cpus_allowed;
5414 }
5415 retval = -EPERM;
5416 if (!check_same_owner(p)) {
5417 rcu_read_lock();
5418 if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) {
5419 rcu_read_unlock();
5420 goto out_free_new_mask;
5421 }
5422 rcu_read_unlock();
5423 }
5424
5425 retval = security_task_setscheduler(p);
5426 if (retval)
5427 goto out_free_new_mask;
5428
5429
5430 cpuset_cpus_allowed(p, cpus_allowed);
5431 cpumask_and(new_mask, in_mask, cpus_allowed);
5432
5433 /*
5434 * Since bandwidth control happens on root_domain basis,
5435 * if admission test is enabled, we only admit -deadline
5436 * tasks allowed to run on all the CPUs in the task's
5437 * root_domain.
5438 */
5439#ifdef CONFIG_SMP
5440 if (task_has_dl_policy(p) && dl_bandwidth_enabled()) {
5441 rcu_read_lock();
5442 if (!cpumask_subset(task_rq(p)->rd->span, new_mask)) {
5443 retval = -EBUSY;
5444 rcu_read_unlock();
5445 goto out_free_new_mask;
5446 }
5447 rcu_read_unlock();
5448 }
5449#endif
5450again:
5451 retval = __set_cpus_allowed_ptr(p, new_mask, true);
5452
5453 if (!retval) {
5454 cpuset_cpus_allowed(p, cpus_allowed);
5455 if (!cpumask_subset(new_mask, cpus_allowed)) {
5456 /*
5457 * We must have raced with a concurrent cpuset
5458 * update. Just reset the cpus_allowed to the
5459 * cpuset's cpus_allowed
5460 */
5461 cpumask_copy(new_mask, cpus_allowed);
5462 goto again;
5463 }
5464 }
5465out_free_new_mask:
5466 free_cpumask_var(new_mask);
5467out_free_cpus_allowed:
5468 free_cpumask_var(cpus_allowed);
5469out_put_task:
5470 put_task_struct(p);
5471 return retval;
5472}
5473
5474static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
5475 struct cpumask *new_mask)
5476{
5477 if (len < cpumask_size())
5478 cpumask_clear(new_mask);
5479 else if (len > cpumask_size())
5480 len = cpumask_size();
5481
5482 return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
5483}
5484
5485/**
5486 * sys_sched_setaffinity - set the CPU affinity of a process
5487 * @pid: pid of the process
5488 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5489 * @user_mask_ptr: user-space pointer to the new CPU mask
5490 *
5491 * Return: 0 on success. An error code otherwise.
5492 */
5493SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len,
5494 unsigned long __user *, user_mask_ptr)
5495{
5496 cpumask_var_t new_mask;
5497 int retval;
5498
5499 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
5500 return -ENOMEM;
5501
5502 retval = get_user_cpu_mask(user_mask_ptr, len, new_mask);
5503 if (retval == 0)
5504 retval = sched_setaffinity(pid, new_mask);
5505 free_cpumask_var(new_mask);
5506 return retval;
5507}
5508
5509long sched_getaffinity(pid_t pid, struct cpumask *mask)
5510{
5511 struct task_struct *p;
5512 unsigned long flags;
5513 int retval;
5514
5515 rcu_read_lock();
5516
5517 retval = -ESRCH;
5518 p = find_process_by_pid(pid);
5519 if (!p)
5520 goto out_unlock;
5521
5522 retval = security_task_getscheduler(p);
5523 if (retval)
5524 goto out_unlock;
5525
5526 raw_spin_lock_irqsave(&p->pi_lock, flags);
5527 cpumask_and(mask, &p->cpus_mask, cpu_active_mask);
5528 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
5529
5530out_unlock:
5531 rcu_read_unlock();
5532
5533 return retval;
5534}
5535
5536/**
5537 * sys_sched_getaffinity - get the CPU affinity of a process
5538 * @pid: pid of the process
5539 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5540 * @user_mask_ptr: user-space pointer to hold the current CPU mask
5541 *
5542 * Return: size of CPU mask copied to user_mask_ptr on success. An
5543 * error code otherwise.
5544 */
5545SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
5546 unsigned long __user *, user_mask_ptr)
5547{
5548 int ret;
5549 cpumask_var_t mask;
5550
5551 if ((len * BITS_PER_BYTE) < nr_cpu_ids)
5552 return -EINVAL;
5553 if (len & (sizeof(unsigned long)-1))
5554 return -EINVAL;
5555
5556 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
5557 return -ENOMEM;
5558
5559 ret = sched_getaffinity(pid, mask);
5560 if (ret == 0) {
5561 unsigned int retlen = min(len, cpumask_size());
5562
5563 if (copy_to_user(user_mask_ptr, mask, retlen))
5564 ret = -EFAULT;
5565 else
5566 ret = retlen;
5567 }
5568 free_cpumask_var(mask);
5569
5570 return ret;
5571}
5572
5573/**
5574 * sys_sched_yield - yield the current processor to other threads.
5575 *
5576 * This function yields the current CPU to other tasks. If there are no
5577 * other threads running on this CPU then this function will return.
5578 *
5579 * Return: 0.
5580 */
5581static void do_sched_yield(void)
5582{
5583 struct rq_flags rf;
5584 struct rq *rq;
5585
5586 rq = this_rq_lock_irq(&rf);
5587
5588 schedstat_inc(rq->yld_count);
5589 current->sched_class->yield_task(rq);
5590
5591 /*
5592 * Since we are going to call schedule() anyway, there's
5593 * no need to preempt or enable interrupts:
5594 */
5595 preempt_disable();
5596 rq_unlock(rq, &rf);
5597 sched_preempt_enable_no_resched();
5598
5599 schedule();
5600}
5601
5602SYSCALL_DEFINE0(sched_yield)
5603{
5604 do_sched_yield();
5605 return 0;
5606}
5607
5608#ifndef CONFIG_PREEMPTION
5609int __sched _cond_resched(void)
5610{
5611 if (should_resched(0)) {
5612 preempt_schedule_common();
5613 return 1;
5614 }
5615 rcu_all_qs();
5616 return 0;
5617}
5618EXPORT_SYMBOL(_cond_resched);
5619#endif
5620
5621/*
5622 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
5623 * call schedule, and on return reacquire the lock.
5624 *
5625 * This works OK both with and without CONFIG_PREEMPTION. We do strange low-level
5626 * operations here to prevent schedule() from being called twice (once via
5627 * spin_unlock(), once by hand).
5628 */
5629int __cond_resched_lock(spinlock_t *lock)
5630{
5631 int resched = should_resched(PREEMPT_LOCK_OFFSET);
5632 int ret = 0;
5633
5634 lockdep_assert_held(lock);
5635
5636 if (spin_needbreak(lock) || resched) {
5637 spin_unlock(lock);
5638 if (resched)
5639 preempt_schedule_common();
5640 else
5641 cpu_relax();
5642 ret = 1;
5643 spin_lock(lock);
5644 }
5645 return ret;
5646}
5647EXPORT_SYMBOL(__cond_resched_lock);
5648
5649/**
5650 * yield - yield the current processor to other threads.
5651 *
5652 * Do not ever use this function, there's a 99% chance you're doing it wrong.
5653 *
5654 * The scheduler is at all times free to pick the calling task as the most
5655 * eligible task to run, if removing the yield() call from your code breaks
5656 * it, its already broken.
5657 *
5658 * Typical broken usage is:
5659 *
5660 * while (!event)
5661 * yield();
5662 *
5663 * where one assumes that yield() will let 'the other' process run that will
5664 * make event true. If the current task is a SCHED_FIFO task that will never
5665 * happen. Never use yield() as a progress guarantee!!
5666 *
5667 * If you want to use yield() to wait for something, use wait_event().
5668 * If you want to use yield() to be 'nice' for others, use cond_resched().
5669 * If you still want to use yield(), do not!
5670 */
5671void __sched yield(void)
5672{
5673 set_current_state(TASK_RUNNING);
5674 do_sched_yield();
5675}
5676EXPORT_SYMBOL(yield);
5677
5678/**
5679 * yield_to - yield the current processor to another thread in
5680 * your thread group, or accelerate that thread toward the
5681 * processor it's on.
5682 * @p: target task
5683 * @preempt: whether task preemption is allowed or not
5684 *
5685 * It's the caller's job to ensure that the target task struct
5686 * can't go away on us before we can do any checks.
5687 *
5688 * Return:
5689 * true (>0) if we indeed boosted the target task.
5690 * false (0) if we failed to boost the target.
5691 * -ESRCH if there's no task to yield to.
5692 */
5693int __sched yield_to(struct task_struct *p, bool preempt)
5694{
5695 struct task_struct *curr = current;
5696 struct rq *rq, *p_rq;
5697 unsigned long flags;
5698 int yielded = 0;
5699
5700 local_irq_save(flags);
5701 rq = this_rq();
5702
5703again:
5704 p_rq = task_rq(p);
5705 /*
5706 * If we're the only runnable task on the rq and target rq also
5707 * has only one task, there's absolutely no point in yielding.
5708 */
5709 if (rq->nr_running == 1 && p_rq->nr_running == 1) {
5710 yielded = -ESRCH;
5711 goto out_irq;
5712 }
5713
5714 double_rq_lock(rq, p_rq);
5715 if (task_rq(p) != p_rq) {
5716 double_rq_unlock(rq, p_rq);
5717 goto again;
5718 }
5719
5720 if (!curr->sched_class->yield_to_task)
5721 goto out_unlock;
5722
5723 if (curr->sched_class != p->sched_class)
5724 goto out_unlock;
5725
5726 if (task_running(p_rq, p) || p->state)
5727 goto out_unlock;
5728
5729 yielded = curr->sched_class->yield_to_task(rq, p, preempt);
5730 if (yielded) {
5731 schedstat_inc(rq->yld_count);
5732 /*
5733 * Make p's CPU reschedule; pick_next_entity takes care of
5734 * fairness.
5735 */
5736 if (preempt && rq != p_rq)
5737 resched_curr(p_rq);
5738 }
5739
5740out_unlock:
5741 double_rq_unlock(rq, p_rq);
5742out_irq:
5743 local_irq_restore(flags);
5744
5745 if (yielded > 0)
5746 schedule();
5747
5748 return yielded;
5749}
5750EXPORT_SYMBOL_GPL(yield_to);
5751
5752int io_schedule_prepare(void)
5753{
5754 int old_iowait = current->in_iowait;
5755
5756 current->in_iowait = 1;
5757 blk_schedule_flush_plug(current);
5758
5759 return old_iowait;
5760}
5761
5762void io_schedule_finish(int token)
5763{
5764 current->in_iowait = token;
5765}
5766
5767/*
5768 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
5769 * that process accounting knows that this is a task in IO wait state.
5770 */
5771long __sched io_schedule_timeout(long timeout)
5772{
5773 int token;
5774 long ret;
5775
5776 token = io_schedule_prepare();
5777 ret = schedule_timeout(timeout);
5778 io_schedule_finish(token);
5779
5780 return ret;
5781}
5782EXPORT_SYMBOL(io_schedule_timeout);
5783
5784void __sched io_schedule(void)
5785{
5786 int token;
5787
5788 token = io_schedule_prepare();
5789 schedule();
5790 io_schedule_finish(token);
5791}
5792EXPORT_SYMBOL(io_schedule);
5793
5794/**
5795 * sys_sched_get_priority_max - return maximum RT priority.
5796 * @policy: scheduling class.
5797 *
5798 * Return: On success, this syscall returns the maximum
5799 * rt_priority that can be used by a given scheduling class.
5800 * On failure, a negative error code is returned.
5801 */
5802SYSCALL_DEFINE1(sched_get_priority_max, int, policy)
5803{
5804 int ret = -EINVAL;
5805
5806 switch (policy) {
5807 case SCHED_FIFO:
5808 case SCHED_RR:
5809 ret = MAX_USER_RT_PRIO-1;
5810 break;
5811 case SCHED_DEADLINE:
5812 case SCHED_NORMAL:
5813 case SCHED_BATCH:
5814 case SCHED_IDLE:
5815 ret = 0;
5816 break;
5817 }
5818 return ret;
5819}
5820
5821/**
5822 * sys_sched_get_priority_min - return minimum RT priority.
5823 * @policy: scheduling class.
5824 *
5825 * Return: On success, this syscall returns the minimum
5826 * rt_priority that can be used by a given scheduling class.
5827 * On failure, a negative error code is returned.
5828 */
5829SYSCALL_DEFINE1(sched_get_priority_min, int, policy)
5830{
5831 int ret = -EINVAL;
5832
5833 switch (policy) {
5834 case SCHED_FIFO:
5835 case SCHED_RR:
5836 ret = 1;
5837 break;
5838 case SCHED_DEADLINE:
5839 case SCHED_NORMAL:
5840 case SCHED_BATCH:
5841 case SCHED_IDLE:
5842 ret = 0;
5843 }
5844 return ret;
5845}
5846
5847static int sched_rr_get_interval(pid_t pid, struct timespec64 *t)
5848{
5849 struct task_struct *p;
5850 unsigned int time_slice;
5851 struct rq_flags rf;
5852 struct rq *rq;
5853 int retval;
5854
5855 if (pid < 0)
5856 return -EINVAL;
5857
5858 retval = -ESRCH;
5859 rcu_read_lock();
5860 p = find_process_by_pid(pid);
5861 if (!p)
5862 goto out_unlock;
5863
5864 retval = security_task_getscheduler(p);
5865 if (retval)
5866 goto out_unlock;
5867
5868 rq = task_rq_lock(p, &rf);
5869 time_slice = 0;
5870 if (p->sched_class->get_rr_interval)
5871 time_slice = p->sched_class->get_rr_interval(rq, p);
5872 task_rq_unlock(rq, p, &rf);
5873
5874 rcu_read_unlock();
5875 jiffies_to_timespec64(time_slice, t);
5876 return 0;
5877
5878out_unlock:
5879 rcu_read_unlock();
5880 return retval;
5881}
5882
5883/**
5884 * sys_sched_rr_get_interval - return the default timeslice of a process.
5885 * @pid: pid of the process.
5886 * @interval: userspace pointer to the timeslice value.
5887 *
5888 * this syscall writes the default timeslice value of a given process
5889 * into the user-space timespec buffer. A value of '0' means infinity.
5890 *
5891 * Return: On success, 0 and the timeslice is in @interval. Otherwise,
5892 * an error code.
5893 */
5894SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid,
5895 struct __kernel_timespec __user *, interval)
5896{
5897 struct timespec64 t;
5898 int retval = sched_rr_get_interval(pid, &t);
5899
5900 if (retval == 0)
5901 retval = put_timespec64(&t, interval);
5902
5903 return retval;
5904}
5905
5906#ifdef CONFIG_COMPAT_32BIT_TIME
5907SYSCALL_DEFINE2(sched_rr_get_interval_time32, pid_t, pid,
5908 struct old_timespec32 __user *, interval)
5909{
5910 struct timespec64 t;
5911 int retval = sched_rr_get_interval(pid, &t);
5912
5913 if (retval == 0)
5914 retval = put_old_timespec32(&t, interval);
5915 return retval;
5916}
5917#endif
5918
5919void sched_show_task(struct task_struct *p)
5920{
5921 unsigned long free = 0;
5922 int ppid;
5923
5924 if (!try_get_task_stack(p))
5925 return;
5926
5927 printk(KERN_INFO "%-15.15s %c", p->comm, task_state_to_char(p));
5928
5929 if (p->state == TASK_RUNNING)
5930 printk(KERN_CONT " running task ");
5931#ifdef CONFIG_DEBUG_STACK_USAGE
5932 free = stack_not_used(p);
5933#endif
5934 ppid = 0;
5935 rcu_read_lock();
5936 if (pid_alive(p))
5937 ppid = task_pid_nr(rcu_dereference(p->real_parent));
5938 rcu_read_unlock();
5939 printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free,
5940 task_pid_nr(p), ppid,
5941 (unsigned long)task_thread_info(p)->flags);
5942
5943 print_worker_info(KERN_INFO, p);
5944 show_stack(p, NULL);
5945 put_task_stack(p);
5946}
5947EXPORT_SYMBOL_GPL(sched_show_task);
5948
5949static inline bool
5950state_filter_match(unsigned long state_filter, struct task_struct *p)
5951{
5952 /* no filter, everything matches */
5953 if (!state_filter)
5954 return true;
5955
5956 /* filter, but doesn't match */
5957 if (!(p->state & state_filter))
5958 return false;
5959
5960 /*
5961 * When looking for TASK_UNINTERRUPTIBLE skip TASK_IDLE (allows
5962 * TASK_KILLABLE).
5963 */
5964 if (state_filter == TASK_UNINTERRUPTIBLE && p->state == TASK_IDLE)
5965 return false;
5966
5967 return true;
5968}
5969
5970
5971void show_state_filter(unsigned long state_filter)
5972{
5973 struct task_struct *g, *p;
5974
5975#if BITS_PER_LONG == 32
5976 printk(KERN_INFO
5977 " task PC stack pid father\n");
5978#else
5979 printk(KERN_INFO
5980 " task PC stack pid father\n");
5981#endif
5982 rcu_read_lock();
5983 for_each_process_thread(g, p) {
5984 /*
5985 * reset the NMI-timeout, listing all files on a slow
5986 * console might take a lot of time:
5987 * Also, reset softlockup watchdogs on all CPUs, because
5988 * another CPU might be blocked waiting for us to process
5989 * an IPI.
5990 */
5991 touch_nmi_watchdog();
5992 touch_all_softlockup_watchdogs();
5993 if (state_filter_match(state_filter, p))
5994 sched_show_task(p);
5995 }
5996
5997#ifdef CONFIG_SCHED_DEBUG
5998 if (!state_filter)
5999 sysrq_sched_debug_show();
6000#endif
6001 rcu_read_unlock();
6002 /*
6003 * Only show locks if all tasks are dumped:
6004 */
6005 if (!state_filter)
6006 debug_show_all_locks();
6007}
6008
6009/**
6010 * init_idle - set up an idle thread for a given CPU
6011 * @idle: task in question
6012 * @cpu: CPU the idle task belongs to
6013 *
6014 * NOTE: this function does not set the idle thread's NEED_RESCHED
6015 * flag, to make booting more robust.
6016 */
6017void init_idle(struct task_struct *idle, int cpu)
6018{
6019 struct rq *rq = cpu_rq(cpu);
6020 unsigned long flags;
6021
6022 __sched_fork(0, idle);
6023
6024 raw_spin_lock_irqsave(&idle->pi_lock, flags);
6025 raw_spin_lock(&rq->lock);
6026
6027 idle->state = TASK_RUNNING;
6028 idle->se.exec_start = sched_clock();
6029 idle->flags |= PF_IDLE;
6030
6031 kasan_unpoison_task_stack(idle);
6032
6033#ifdef CONFIG_SMP
6034 /*
6035 * Its possible that init_idle() gets called multiple times on a task,
6036 * in that case do_set_cpus_allowed() will not do the right thing.
6037 *
6038 * And since this is boot we can forgo the serialization.
6039 */
6040 set_cpus_allowed_common(idle, cpumask_of(cpu));
6041#endif
6042 /*
6043 * We're having a chicken and egg problem, even though we are
6044 * holding rq->lock, the CPU isn't yet set to this CPU so the
6045 * lockdep check in task_group() will fail.
6046 *
6047 * Similar case to sched_fork(). / Alternatively we could
6048 * use task_rq_lock() here and obtain the other rq->lock.
6049 *
6050 * Silence PROVE_RCU
6051 */
6052 rcu_read_lock();
6053 __set_task_cpu(idle, cpu);
6054 rcu_read_unlock();
6055
6056 rq->idle = idle;
6057 rcu_assign_pointer(rq->curr, idle);
6058 idle->on_rq = TASK_ON_RQ_QUEUED;
6059#ifdef CONFIG_SMP
6060 idle->on_cpu = 1;
6061#endif
6062 raw_spin_unlock(&rq->lock);
6063 raw_spin_unlock_irqrestore(&idle->pi_lock, flags);
6064
6065 /* Set the preempt count _outside_ the spinlocks! */
6066 init_idle_preempt_count(idle, cpu);
6067
6068 /*
6069 * The idle tasks have their own, simple scheduling class:
6070 */
6071 idle->sched_class = &idle_sched_class;
6072 ftrace_graph_init_idle_task(idle, cpu);
6073 vtime_init_idle(idle, cpu);
6074#ifdef CONFIG_SMP
6075 sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu);
6076#endif
6077}
6078
6079#ifdef CONFIG_SMP
6080
6081int cpuset_cpumask_can_shrink(const struct cpumask *cur,
6082 const struct cpumask *trial)
6083{
6084 int ret = 1;
6085
6086 if (!cpumask_weight(cur))
6087 return ret;
6088
6089 ret = dl_cpuset_cpumask_can_shrink(cur, trial);
6090
6091 return ret;
6092}
6093
6094int task_can_attach(struct task_struct *p,
6095 const struct cpumask *cs_cpus_allowed)
6096{
6097 int ret = 0;
6098
6099 /*
6100 * Kthreads which disallow setaffinity shouldn't be moved
6101 * to a new cpuset; we don't want to change their CPU
6102 * affinity and isolating such threads by their set of
6103 * allowed nodes is unnecessary. Thus, cpusets are not
6104 * applicable for such threads. This prevents checking for
6105 * success of set_cpus_allowed_ptr() on all attached tasks
6106 * before cpus_mask may be changed.
6107 */
6108 if (p->flags & PF_NO_SETAFFINITY) {
6109 ret = -EINVAL;
6110 goto out;
6111 }
6112
6113 if (dl_task(p) && !cpumask_intersects(task_rq(p)->rd->span,
6114 cs_cpus_allowed))
6115 ret = dl_task_can_attach(p, cs_cpus_allowed);
6116
6117out:
6118 return ret;
6119}
6120
6121bool sched_smp_initialized __read_mostly;
6122
6123#ifdef CONFIG_NUMA_BALANCING
6124/* Migrate current task p to target_cpu */
6125int migrate_task_to(struct task_struct *p, int target_cpu)
6126{
6127 struct migration_arg arg = { p, target_cpu };
6128 int curr_cpu = task_cpu(p);
6129
6130 if (curr_cpu == target_cpu)
6131 return 0;
6132
6133 if (!cpumask_test_cpu(target_cpu, p->cpus_ptr))
6134 return -EINVAL;
6135
6136 /* TODO: This is not properly updating schedstats */
6137
6138 trace_sched_move_numa(p, curr_cpu, target_cpu);
6139 return stop_one_cpu(curr_cpu, migration_cpu_stop, &arg);
6140}
6141
6142/*
6143 * Requeue a task on a given node and accurately track the number of NUMA
6144 * tasks on the runqueues
6145 */
6146void sched_setnuma(struct task_struct *p, int nid)
6147{
6148 bool queued, running;
6149 struct rq_flags rf;
6150 struct rq *rq;
6151
6152 rq = task_rq_lock(p, &rf);
6153 queued = task_on_rq_queued(p);
6154 running = task_current(rq, p);
6155
6156 if (queued)
6157 dequeue_task(rq, p, DEQUEUE_SAVE);
6158 if (running)
6159 put_prev_task(rq, p);
6160
6161 p->numa_preferred_nid = nid;
6162
6163 if (queued)
6164 enqueue_task(rq, p, ENQUEUE_RESTORE | ENQUEUE_NOCLOCK);
6165 if (running)
6166 set_next_task(rq, p);
6167 task_rq_unlock(rq, p, &rf);
6168}
6169#endif /* CONFIG_NUMA_BALANCING */
6170
6171#ifdef CONFIG_HOTPLUG_CPU
6172/*
6173 * Ensure that the idle task is using init_mm right before its CPU goes
6174 * offline.
6175 */
6176void idle_task_exit(void)
6177{
6178 struct mm_struct *mm = current->active_mm;
6179
6180 BUG_ON(cpu_online(smp_processor_id()));
6181
6182 if (mm != &init_mm) {
6183 switch_mm(mm, &init_mm, current);
6184 current->active_mm = &init_mm;
6185 finish_arch_post_lock_switch();
6186 }
6187 mmdrop(mm);
6188}
6189
6190/*
6191 * Since this CPU is going 'away' for a while, fold any nr_active delta
6192 * we might have. Assumes we're called after migrate_tasks() so that the
6193 * nr_active count is stable. We need to take the teardown thread which
6194 * is calling this into account, so we hand in adjust = 1 to the load
6195 * calculation.
6196 *
6197 * Also see the comment "Global load-average calculations".
6198 */
6199static void calc_load_migrate(struct rq *rq)
6200{
6201 long delta = calc_load_fold_active(rq, 1);
6202 if (delta)
6203 atomic_long_add(delta, &calc_load_tasks);
6204}
6205
6206static struct task_struct *__pick_migrate_task(struct rq *rq)
6207{
6208 const struct sched_class *class;
6209 struct task_struct *next;
6210
6211 for_each_class(class) {
6212 next = class->pick_next_task(rq, NULL, NULL);
6213 if (next) {
6214 next->sched_class->put_prev_task(rq, next);
6215 return next;
6216 }
6217 }
6218
6219 /* The idle class should always have a runnable task */
6220 BUG();
6221}
6222
6223/*
6224 * Migrate all tasks from the rq, sleeping tasks will be migrated by
6225 * try_to_wake_up()->select_task_rq().
6226 *
6227 * Called with rq->lock held even though we'er in stop_machine() and
6228 * there's no concurrency possible, we hold the required locks anyway
6229 * because of lock validation efforts.
6230 */
6231static void migrate_tasks(struct rq *dead_rq, struct rq_flags *rf)
6232{
6233 struct rq *rq = dead_rq;
6234 struct task_struct *next, *stop = rq->stop;
6235 struct rq_flags orf = *rf;
6236 int dest_cpu;
6237
6238 /*
6239 * Fudge the rq selection such that the below task selection loop
6240 * doesn't get stuck on the currently eligible stop task.
6241 *
6242 * We're currently inside stop_machine() and the rq is either stuck
6243 * in the stop_machine_cpu_stop() loop, or we're executing this code,
6244 * either way we should never end up calling schedule() until we're
6245 * done here.
6246 */
6247 rq->stop = NULL;
6248
6249 /*
6250 * put_prev_task() and pick_next_task() sched
6251 * class method both need to have an up-to-date
6252 * value of rq->clock[_task]
6253 */
6254 update_rq_clock(rq);
6255
6256 for (;;) {
6257 /*
6258 * There's this thread running, bail when that's the only
6259 * remaining thread:
6260 */
6261 if (rq->nr_running == 1)
6262 break;
6263
6264 next = __pick_migrate_task(rq);
6265
6266 /*
6267 * Rules for changing task_struct::cpus_mask are holding
6268 * both pi_lock and rq->lock, such that holding either
6269 * stabilizes the mask.
6270 *
6271 * Drop rq->lock is not quite as disastrous as it usually is
6272 * because !cpu_active at this point, which means load-balance
6273 * will not interfere. Also, stop-machine.
6274 */
6275 rq_unlock(rq, rf);
6276 raw_spin_lock(&next->pi_lock);
6277 rq_relock(rq, rf);
6278
6279 /*
6280 * Since we're inside stop-machine, _nothing_ should have
6281 * changed the task, WARN if weird stuff happened, because in
6282 * that case the above rq->lock drop is a fail too.
6283 */
6284 if (WARN_ON(task_rq(next) != rq || !task_on_rq_queued(next))) {
6285 raw_spin_unlock(&next->pi_lock);
6286 continue;
6287 }
6288
6289 /* Find suitable destination for @next, with force if needed. */
6290 dest_cpu = select_fallback_rq(dead_rq->cpu, next);
6291 rq = __migrate_task(rq, rf, next, dest_cpu);
6292 if (rq != dead_rq) {
6293 rq_unlock(rq, rf);
6294 rq = dead_rq;
6295 *rf = orf;
6296 rq_relock(rq, rf);
6297 }
6298 raw_spin_unlock(&next->pi_lock);
6299 }
6300
6301 rq->stop = stop;
6302}
6303#endif /* CONFIG_HOTPLUG_CPU */
6304
6305void set_rq_online(struct rq *rq)
6306{
6307 if (!rq->online) {
6308 const struct sched_class *class;
6309
6310 cpumask_set_cpu(rq->cpu, rq->rd->online);
6311 rq->online = 1;
6312
6313 for_each_class(class) {
6314 if (class->rq_online)
6315 class->rq_online(rq);
6316 }
6317 }
6318}
6319
6320void set_rq_offline(struct rq *rq)
6321{
6322 if (rq->online) {
6323 const struct sched_class *class;
6324
6325 for_each_class(class) {
6326 if (class->rq_offline)
6327 class->rq_offline(rq);
6328 }
6329
6330 cpumask_clear_cpu(rq->cpu, rq->rd->online);
6331 rq->online = 0;
6332 }
6333}
6334
6335/*
6336 * used to mark begin/end of suspend/resume:
6337 */
6338static int num_cpus_frozen;
6339
6340/*
6341 * Update cpusets according to cpu_active mask. If cpusets are
6342 * disabled, cpuset_update_active_cpus() becomes a simple wrapper
6343 * around partition_sched_domains().
6344 *
6345 * If we come here as part of a suspend/resume, don't touch cpusets because we
6346 * want to restore it back to its original state upon resume anyway.
6347 */
6348static void cpuset_cpu_active(void)
6349{
6350 if (cpuhp_tasks_frozen) {
6351 /*
6352 * num_cpus_frozen tracks how many CPUs are involved in suspend
6353 * resume sequence. As long as this is not the last online
6354 * operation in the resume sequence, just build a single sched
6355 * domain, ignoring cpusets.
6356 */
6357 partition_sched_domains(1, NULL, NULL);
6358 if (--num_cpus_frozen)
6359 return;
6360 /*
6361 * This is the last CPU online operation. So fall through and
6362 * restore the original sched domains by considering the
6363 * cpuset configurations.
6364 */
6365 cpuset_force_rebuild();
6366 }
6367 cpuset_update_active_cpus();
6368}
6369
6370static int cpuset_cpu_inactive(unsigned int cpu)
6371{
6372 if (!cpuhp_tasks_frozen) {
6373 if (dl_cpu_busy(cpu))
6374 return -EBUSY;
6375 cpuset_update_active_cpus();
6376 } else {
6377 num_cpus_frozen++;
6378 partition_sched_domains(1, NULL, NULL);
6379 }
6380 return 0;
6381}
6382
6383int sched_cpu_activate(unsigned int cpu)
6384{
6385 struct rq *rq = cpu_rq(cpu);
6386 struct rq_flags rf;
6387
6388#ifdef CONFIG_SCHED_SMT
6389 /*
6390 * When going up, increment the number of cores with SMT present.
6391 */
6392 if (cpumask_weight(cpu_smt_mask(cpu)) == 2)
6393 static_branch_inc_cpuslocked(&sched_smt_present);
6394#endif
6395 set_cpu_active(cpu, true);
6396
6397 if (sched_smp_initialized) {
6398 sched_domains_numa_masks_set(cpu);
6399 cpuset_cpu_active();
6400 }
6401
6402 /*
6403 * Put the rq online, if not already. This happens:
6404 *
6405 * 1) In the early boot process, because we build the real domains
6406 * after all CPUs have been brought up.
6407 *
6408 * 2) At runtime, if cpuset_cpu_active() fails to rebuild the
6409 * domains.
6410 */
6411 rq_lock_irqsave(rq, &rf);
6412 if (rq->rd) {
6413 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
6414 set_rq_online(rq);
6415 }
6416 rq_unlock_irqrestore(rq, &rf);
6417
6418 return 0;
6419}
6420
6421int sched_cpu_deactivate(unsigned int cpu)
6422{
6423 int ret;
6424
6425 set_cpu_active(cpu, false);
6426 /*
6427 * We've cleared cpu_active_mask, wait for all preempt-disabled and RCU
6428 * users of this state to go away such that all new such users will
6429 * observe it.
6430 *
6431 * Do sync before park smpboot threads to take care the rcu boost case.
6432 */
6433 synchronize_rcu();
6434
6435#ifdef CONFIG_SCHED_SMT
6436 /*
6437 * When going down, decrement the number of cores with SMT present.
6438 */
6439 if (cpumask_weight(cpu_smt_mask(cpu)) == 2)
6440 static_branch_dec_cpuslocked(&sched_smt_present);
6441#endif
6442
6443 if (!sched_smp_initialized)
6444 return 0;
6445
6446 ret = cpuset_cpu_inactive(cpu);
6447 if (ret) {
6448 set_cpu_active(cpu, true);
6449 return ret;
6450 }
6451 sched_domains_numa_masks_clear(cpu);
6452 return 0;
6453}
6454
6455static void sched_rq_cpu_starting(unsigned int cpu)
6456{
6457 struct rq *rq = cpu_rq(cpu);
6458
6459 rq->calc_load_update = calc_load_update;
6460 update_max_interval();
6461}
6462
6463int sched_cpu_starting(unsigned int cpu)
6464{
6465 sched_rq_cpu_starting(cpu);
6466 sched_tick_start(cpu);
6467 return 0;
6468}
6469
6470#ifdef CONFIG_HOTPLUG_CPU
6471int sched_cpu_dying(unsigned int cpu)
6472{
6473 struct rq *rq = cpu_rq(cpu);
6474 struct rq_flags rf;
6475
6476 /* Handle pending wakeups and then migrate everything off */
6477 sched_ttwu_pending();
6478 sched_tick_stop(cpu);
6479
6480 rq_lock_irqsave(rq, &rf);
6481 if (rq->rd) {
6482 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
6483 set_rq_offline(rq);
6484 }
6485 migrate_tasks(rq, &rf);
6486 BUG_ON(rq->nr_running != 1);
6487 rq_unlock_irqrestore(rq, &rf);
6488
6489 calc_load_migrate(rq);
6490 update_max_interval();
6491 nohz_balance_exit_idle(rq);
6492 hrtick_clear(rq);
6493 return 0;
6494}
6495#endif
6496
6497void __init sched_init_smp(void)
6498{
6499 sched_init_numa();
6500
6501 /*
6502 * There's no userspace yet to cause hotplug operations; hence all the
6503 * CPU masks are stable and all blatant races in the below code cannot
6504 * happen.
6505 */
6506 mutex_lock(&sched_domains_mutex);
6507 sched_init_domains(cpu_active_mask);
6508 mutex_unlock(&sched_domains_mutex);
6509
6510 /* Move init over to a non-isolated CPU */
6511 if (set_cpus_allowed_ptr(current, housekeeping_cpumask(HK_FLAG_DOMAIN)) < 0)
6512 BUG();
6513 sched_init_granularity();
6514
6515 init_sched_rt_class();
6516 init_sched_dl_class();
6517
6518 sched_smp_initialized = true;
6519}
6520
6521static int __init migration_init(void)
6522{
6523 sched_cpu_starting(smp_processor_id());
6524 return 0;
6525}
6526early_initcall(migration_init);
6527
6528#else
6529void __init sched_init_smp(void)
6530{
6531 sched_init_granularity();
6532}
6533#endif /* CONFIG_SMP */
6534
6535int in_sched_functions(unsigned long addr)
6536{
6537 return in_lock_functions(addr) ||
6538 (addr >= (unsigned long)__sched_text_start
6539 && addr < (unsigned long)__sched_text_end);
6540}
6541
6542#ifdef CONFIG_CGROUP_SCHED
6543/*
6544 * Default task group.
6545 * Every task in system belongs to this group at bootup.
6546 */
6547struct task_group root_task_group;
6548LIST_HEAD(task_groups);
6549
6550/* Cacheline aligned slab cache for task_group */
6551static struct kmem_cache *task_group_cache __read_mostly;
6552#endif
6553
6554DECLARE_PER_CPU(cpumask_var_t, load_balance_mask);
6555DECLARE_PER_CPU(cpumask_var_t, select_idle_mask);
6556
6557void __init sched_init(void)
6558{
6559 unsigned long ptr = 0;
6560 int i;
6561
6562 wait_bit_init();
6563
6564#ifdef CONFIG_FAIR_GROUP_SCHED
6565 ptr += 2 * nr_cpu_ids * sizeof(void **);
6566#endif
6567#ifdef CONFIG_RT_GROUP_SCHED
6568 ptr += 2 * nr_cpu_ids * sizeof(void **);
6569#endif
6570 if (ptr) {
6571 ptr = (unsigned long)kzalloc(ptr, GFP_NOWAIT);
6572
6573#ifdef CONFIG_FAIR_GROUP_SCHED
6574 root_task_group.se = (struct sched_entity **)ptr;
6575 ptr += nr_cpu_ids * sizeof(void **);
6576
6577 root_task_group.cfs_rq = (struct cfs_rq **)ptr;
6578 ptr += nr_cpu_ids * sizeof(void **);
6579
6580#endif /* CONFIG_FAIR_GROUP_SCHED */
6581#ifdef CONFIG_RT_GROUP_SCHED
6582 root_task_group.rt_se = (struct sched_rt_entity **)ptr;
6583 ptr += nr_cpu_ids * sizeof(void **);
6584
6585 root_task_group.rt_rq = (struct rt_rq **)ptr;
6586 ptr += nr_cpu_ids * sizeof(void **);
6587
6588#endif /* CONFIG_RT_GROUP_SCHED */
6589 }
6590#ifdef CONFIG_CPUMASK_OFFSTACK
6591 for_each_possible_cpu(i) {
6592 per_cpu(load_balance_mask, i) = (cpumask_var_t)kzalloc_node(
6593 cpumask_size(), GFP_KERNEL, cpu_to_node(i));
6594 per_cpu(select_idle_mask, i) = (cpumask_var_t)kzalloc_node(
6595 cpumask_size(), GFP_KERNEL, cpu_to_node(i));
6596 }
6597#endif /* CONFIG_CPUMASK_OFFSTACK */
6598
6599 init_rt_bandwidth(&def_rt_bandwidth, global_rt_period(), global_rt_runtime());
6600 init_dl_bandwidth(&def_dl_bandwidth, global_rt_period(), global_rt_runtime());
6601
6602#ifdef CONFIG_SMP
6603 init_defrootdomain();
6604#endif
6605
6606#ifdef CONFIG_RT_GROUP_SCHED
6607 init_rt_bandwidth(&root_task_group.rt_bandwidth,
6608 global_rt_period(), global_rt_runtime());
6609#endif /* CONFIG_RT_GROUP_SCHED */
6610
6611#ifdef CONFIG_CGROUP_SCHED
6612 task_group_cache = KMEM_CACHE(task_group, 0);
6613
6614 list_add(&root_task_group.list, &task_groups);
6615 INIT_LIST_HEAD(&root_task_group.children);
6616 INIT_LIST_HEAD(&root_task_group.siblings);
6617 autogroup_init(&init_task);
6618#endif /* CONFIG_CGROUP_SCHED */
6619
6620 for_each_possible_cpu(i) {
6621 struct rq *rq;
6622
6623 rq = cpu_rq(i);
6624 raw_spin_lock_init(&rq->lock);
6625 rq->nr_running = 0;
6626 rq->calc_load_active = 0;
6627 rq->calc_load_update = jiffies + LOAD_FREQ;
6628 init_cfs_rq(&rq->cfs);
6629 init_rt_rq(&rq->rt);
6630 init_dl_rq(&rq->dl);
6631#ifdef CONFIG_FAIR_GROUP_SCHED
6632 root_task_group.shares = ROOT_TASK_GROUP_LOAD;
6633 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
6634 rq->tmp_alone_branch = &rq->leaf_cfs_rq_list;
6635 /*
6636 * How much CPU bandwidth does root_task_group get?
6637 *
6638 * In case of task-groups formed thr' the cgroup filesystem, it
6639 * gets 100% of the CPU resources in the system. This overall
6640 * system CPU resource is divided among the tasks of
6641 * root_task_group and its child task-groups in a fair manner,
6642 * based on each entity's (task or task-group's) weight
6643 * (se->load.weight).
6644 *
6645 * In other words, if root_task_group has 10 tasks of weight
6646 * 1024) and two child groups A0 and A1 (of weight 1024 each),
6647 * then A0's share of the CPU resource is:
6648 *
6649 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
6650 *
6651 * We achieve this by letting root_task_group's tasks sit
6652 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
6653 */
6654 init_cfs_bandwidth(&root_task_group.cfs_bandwidth);
6655 init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL);
6656#endif /* CONFIG_FAIR_GROUP_SCHED */
6657
6658 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime;
6659#ifdef CONFIG_RT_GROUP_SCHED
6660 init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL);
6661#endif
6662#ifdef CONFIG_SMP
6663 rq->sd = NULL;
6664 rq->rd = NULL;
6665 rq->cpu_capacity = rq->cpu_capacity_orig = SCHED_CAPACITY_SCALE;
6666 rq->balance_callback = NULL;
6667 rq->active_balance = 0;
6668 rq->next_balance = jiffies;
6669 rq->push_cpu = 0;
6670 rq->cpu = i;
6671 rq->online = 0;
6672 rq->idle_stamp = 0;
6673 rq->avg_idle = 2*sysctl_sched_migration_cost;
6674 rq->max_idle_balance_cost = sysctl_sched_migration_cost;
6675
6676 INIT_LIST_HEAD(&rq->cfs_tasks);
6677
6678 rq_attach_root(rq, &def_root_domain);
6679#ifdef CONFIG_NO_HZ_COMMON
6680 rq->last_load_update_tick = jiffies;
6681 rq->last_blocked_load_update_tick = jiffies;
6682 atomic_set(&rq->nohz_flags, 0);
6683#endif
6684#endif /* CONFIG_SMP */
6685 hrtick_rq_init(rq);
6686 atomic_set(&rq->nr_iowait, 0);
6687 }
6688
6689 set_load_weight(&init_task, false);
6690
6691 /*
6692 * The boot idle thread does lazy MMU switching as well:
6693 */
6694 mmgrab(&init_mm);
6695 enter_lazy_tlb(&init_mm, current);
6696
6697 /*
6698 * Make us the idle thread. Technically, schedule() should not be
6699 * called from this thread, however somewhere below it might be,
6700 * but because we are the idle thread, we just pick up running again
6701 * when this runqueue becomes "idle".
6702 */
6703 init_idle(current, smp_processor_id());
6704
6705 calc_load_update = jiffies + LOAD_FREQ;
6706
6707#ifdef CONFIG_SMP
6708 idle_thread_set_boot_cpu();
6709#endif
6710 init_sched_fair_class();
6711
6712 init_schedstats();
6713
6714 psi_init();
6715
6716 init_uclamp();
6717
6718 scheduler_running = 1;
6719}
6720
6721#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
6722static inline int preempt_count_equals(int preempt_offset)
6723{
6724 int nested = preempt_count() + rcu_preempt_depth();
6725
6726 return (nested == preempt_offset);
6727}
6728
6729void __might_sleep(const char *file, int line, int preempt_offset)
6730{
6731 /*
6732 * Blocking primitives will set (and therefore destroy) current->state,
6733 * since we will exit with TASK_RUNNING make sure we enter with it,
6734 * otherwise we will destroy state.
6735 */
6736 WARN_ONCE(current->state != TASK_RUNNING && current->task_state_change,
6737 "do not call blocking ops when !TASK_RUNNING; "
6738 "state=%lx set at [<%p>] %pS\n",
6739 current->state,
6740 (void *)current->task_state_change,
6741 (void *)current->task_state_change);
6742
6743 ___might_sleep(file, line, preempt_offset);
6744}
6745EXPORT_SYMBOL(__might_sleep);
6746
6747void ___might_sleep(const char *file, int line, int preempt_offset)
6748{
6749 /* Ratelimiting timestamp: */
6750 static unsigned long prev_jiffy;
6751
6752 unsigned long preempt_disable_ip;
6753
6754 /* WARN_ON_ONCE() by default, no rate limit required: */
6755 rcu_sleep_check();
6756
6757 if ((preempt_count_equals(preempt_offset) && !irqs_disabled() &&
6758 !is_idle_task(current) && !current->non_block_count) ||
6759 system_state == SYSTEM_BOOTING || system_state > SYSTEM_RUNNING ||
6760 oops_in_progress)
6761 return;
6762
6763 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
6764 return;
6765 prev_jiffy = jiffies;
6766
6767 /* Save this before calling printk(), since that will clobber it: */
6768 preempt_disable_ip = get_preempt_disable_ip(current);
6769
6770 printk(KERN_ERR
6771 "BUG: sleeping function called from invalid context at %s:%d\n",
6772 file, line);
6773 printk(KERN_ERR
6774 "in_atomic(): %d, irqs_disabled(): %d, non_block: %d, pid: %d, name: %s\n",
6775 in_atomic(), irqs_disabled(), current->non_block_count,
6776 current->pid, current->comm);
6777
6778 if (task_stack_end_corrupted(current))
6779 printk(KERN_EMERG "Thread overran stack, or stack corrupted\n");
6780
6781 debug_show_held_locks(current);
6782 if (irqs_disabled())
6783 print_irqtrace_events(current);
6784 if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)
6785 && !preempt_count_equals(preempt_offset)) {
6786 pr_err("Preemption disabled at:");
6787 print_ip_sym(preempt_disable_ip);
6788 pr_cont("\n");
6789 }
6790 dump_stack();
6791 add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
6792}
6793EXPORT_SYMBOL(___might_sleep);
6794
6795void __cant_sleep(const char *file, int line, int preempt_offset)
6796{
6797 static unsigned long prev_jiffy;
6798
6799 if (irqs_disabled())
6800 return;
6801
6802 if (!IS_ENABLED(CONFIG_PREEMPT_COUNT))
6803 return;
6804
6805 if (preempt_count() > preempt_offset)
6806 return;
6807
6808 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
6809 return;
6810 prev_jiffy = jiffies;
6811
6812 printk(KERN_ERR "BUG: assuming atomic context at %s:%d\n", file, line);
6813 printk(KERN_ERR "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
6814 in_atomic(), irqs_disabled(),
6815 current->pid, current->comm);
6816
6817 debug_show_held_locks(current);
6818 dump_stack();
6819 add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
6820}
6821EXPORT_SYMBOL_GPL(__cant_sleep);
6822#endif
6823
6824#ifdef CONFIG_MAGIC_SYSRQ
6825void normalize_rt_tasks(void)
6826{
6827 struct task_struct *g, *p;
6828 struct sched_attr attr = {
6829 .sched_policy = SCHED_NORMAL,
6830 };
6831
6832 read_lock(&tasklist_lock);
6833 for_each_process_thread(g, p) {
6834 /*
6835 * Only normalize user tasks:
6836 */
6837 if (p->flags & PF_KTHREAD)
6838 continue;
6839
6840 p->se.exec_start = 0;
6841 schedstat_set(p->se.statistics.wait_start, 0);
6842 schedstat_set(p->se.statistics.sleep_start, 0);
6843 schedstat_set(p->se.statistics.block_start, 0);
6844
6845 if (!dl_task(p) && !rt_task(p)) {
6846 /*
6847 * Renice negative nice level userspace
6848 * tasks back to 0:
6849 */
6850 if (task_nice(p) < 0)
6851 set_user_nice(p, 0);
6852 continue;
6853 }
6854
6855 __sched_setscheduler(p, &attr, false, false);
6856 }
6857 read_unlock(&tasklist_lock);
6858}
6859
6860#endif /* CONFIG_MAGIC_SYSRQ */
6861
6862#if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
6863/*
6864 * These functions are only useful for the IA64 MCA handling, or kdb.
6865 *
6866 * They can only be called when the whole system has been
6867 * stopped - every CPU needs to be quiescent, and no scheduling
6868 * activity can take place. Using them for anything else would
6869 * be a serious bug, and as a result, they aren't even visible
6870 * under any other configuration.
6871 */
6872
6873/**
6874 * curr_task - return the current task for a given CPU.
6875 * @cpu: the processor in question.
6876 *
6877 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
6878 *
6879 * Return: The current task for @cpu.
6880 */
6881struct task_struct *curr_task(int cpu)
6882{
6883 return cpu_curr(cpu);
6884}
6885
6886#endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
6887
6888#ifdef CONFIG_IA64
6889/**
6890 * ia64_set_curr_task - set the current task for a given CPU.
6891 * @cpu: the processor in question.
6892 * @p: the task pointer to set.
6893 *
6894 * Description: This function must only be used when non-maskable interrupts
6895 * are serviced on a separate stack. It allows the architecture to switch the
6896 * notion of the current task on a CPU in a non-blocking manner. This function
6897 * must be called with all CPU's synchronized, and interrupts disabled, the
6898 * and caller must save the original value of the current task (see
6899 * curr_task() above) and restore that value before reenabling interrupts and
6900 * re-starting the system.
6901 *
6902 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
6903 */
6904void ia64_set_curr_task(int cpu, struct task_struct *p)
6905{
6906 cpu_curr(cpu) = p;
6907}
6908
6909#endif
6910
6911#ifdef CONFIG_CGROUP_SCHED
6912/* task_group_lock serializes the addition/removal of task groups */
6913static DEFINE_SPINLOCK(task_group_lock);
6914
6915static inline void alloc_uclamp_sched_group(struct task_group *tg,
6916 struct task_group *parent)
6917{
6918#ifdef CONFIG_UCLAMP_TASK_GROUP
6919 enum uclamp_id clamp_id;
6920
6921 for_each_clamp_id(clamp_id) {
6922 uclamp_se_set(&tg->uclamp_req[clamp_id],
6923 uclamp_none(clamp_id), false);
6924 tg->uclamp[clamp_id] = parent->uclamp[clamp_id];
6925 }
6926#endif
6927}
6928
6929static void sched_free_group(struct task_group *tg)
6930{
6931 free_fair_sched_group(tg);
6932 free_rt_sched_group(tg);
6933 autogroup_free(tg);
6934 kmem_cache_free(task_group_cache, tg);
6935}
6936
6937/* allocate runqueue etc for a new task group */
6938struct task_group *sched_create_group(struct task_group *parent)
6939{
6940 struct task_group *tg;
6941
6942 tg = kmem_cache_alloc(task_group_cache, GFP_KERNEL | __GFP_ZERO);
6943 if (!tg)
6944 return ERR_PTR(-ENOMEM);
6945
6946 if (!alloc_fair_sched_group(tg, parent))
6947 goto err;
6948
6949 if (!alloc_rt_sched_group(tg, parent))
6950 goto err;
6951
6952 alloc_uclamp_sched_group(tg, parent);
6953
6954 return tg;
6955
6956err:
6957 sched_free_group(tg);
6958 return ERR_PTR(-ENOMEM);
6959}
6960
6961void sched_online_group(struct task_group *tg, struct task_group *parent)
6962{
6963 unsigned long flags;
6964
6965 spin_lock_irqsave(&task_group_lock, flags);
6966 list_add_rcu(&tg->list, &task_groups);
6967
6968 /* Root should already exist: */
6969 WARN_ON(!parent);
6970
6971 tg->parent = parent;
6972 INIT_LIST_HEAD(&tg->children);
6973 list_add_rcu(&tg->siblings, &parent->children);
6974 spin_unlock_irqrestore(&task_group_lock, flags);
6975
6976 online_fair_sched_group(tg);
6977}
6978
6979/* rcu callback to free various structures associated with a task group */
6980static void sched_free_group_rcu(struct rcu_head *rhp)
6981{
6982 /* Now it should be safe to free those cfs_rqs: */
6983 sched_free_group(container_of(rhp, struct task_group, rcu));
6984}
6985
6986void sched_destroy_group(struct task_group *tg)
6987{
6988 /* Wait for possible concurrent references to cfs_rqs complete: */
6989 call_rcu(&tg->rcu, sched_free_group_rcu);
6990}
6991
6992void sched_offline_group(struct task_group *tg)
6993{
6994 unsigned long flags;
6995
6996 /* End participation in shares distribution: */
6997 unregister_fair_sched_group(tg);
6998
6999 spin_lock_irqsave(&task_group_lock, flags);
7000 list_del_rcu(&tg->list);
7001 list_del_rcu(&tg->siblings);
7002 spin_unlock_irqrestore(&task_group_lock, flags);
7003}
7004
7005static void sched_change_group(struct task_struct *tsk, int type)
7006{
7007 struct task_group *tg;
7008
7009 /*
7010 * All callers are synchronized by task_rq_lock(); we do not use RCU
7011 * which is pointless here. Thus, we pass "true" to task_css_check()
7012 * to prevent lockdep warnings.
7013 */
7014 tg = container_of(task_css_check(tsk, cpu_cgrp_id, true),
7015 struct task_group, css);
7016 tg = autogroup_task_group(tsk, tg);
7017 tsk->sched_task_group = tg;
7018
7019#ifdef CONFIG_FAIR_GROUP_SCHED
7020 if (tsk->sched_class->task_change_group)
7021 tsk->sched_class->task_change_group(tsk, type);
7022 else
7023#endif
7024 set_task_rq(tsk, task_cpu(tsk));
7025}
7026
7027/*
7028 * Change task's runqueue when it moves between groups.
7029 *
7030 * The caller of this function should have put the task in its new group by
7031 * now. This function just updates tsk->se.cfs_rq and tsk->se.parent to reflect
7032 * its new group.
7033 */
7034void sched_move_task(struct task_struct *tsk)
7035{
7036 int queued, running, queue_flags =
7037 DEQUEUE_SAVE | DEQUEUE_MOVE | DEQUEUE_NOCLOCK;
7038 struct rq_flags rf;
7039 struct rq *rq;
7040
7041 rq = task_rq_lock(tsk, &rf);
7042 update_rq_clock(rq);
7043
7044 running = task_current(rq, tsk);
7045 queued = task_on_rq_queued(tsk);
7046
7047 if (queued)
7048 dequeue_task(rq, tsk, queue_flags);
7049 if (running)
7050 put_prev_task(rq, tsk);
7051
7052 sched_change_group(tsk, TASK_MOVE_GROUP);
7053
7054 if (queued)
7055 enqueue_task(rq, tsk, queue_flags);
7056 if (running)
7057 set_next_task(rq, tsk);
7058
7059 task_rq_unlock(rq, tsk, &rf);
7060}
7061
7062static inline struct task_group *css_tg(struct cgroup_subsys_state *css)
7063{
7064 return css ? container_of(css, struct task_group, css) : NULL;
7065}
7066
7067static struct cgroup_subsys_state *
7068cpu_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
7069{
7070 struct task_group *parent = css_tg(parent_css);
7071 struct task_group *tg;
7072
7073 if (!parent) {
7074 /* This is early initialization for the top cgroup */
7075 return &root_task_group.css;
7076 }
7077
7078 tg = sched_create_group(parent);
7079 if (IS_ERR(tg))
7080 return ERR_PTR(-ENOMEM);
7081
7082 return &tg->css;
7083}
7084
7085/* Expose task group only after completing cgroup initialization */
7086static int cpu_cgroup_css_online(struct cgroup_subsys_state *css)
7087{
7088 struct task_group *tg = css_tg(css);
7089 struct task_group *parent = css_tg(css->parent);
7090
7091 if (parent)
7092 sched_online_group(tg, parent);
7093 return 0;
7094}
7095
7096static void cpu_cgroup_css_released(struct cgroup_subsys_state *css)
7097{
7098 struct task_group *tg = css_tg(css);
7099
7100 sched_offline_group(tg);
7101}
7102
7103static void cpu_cgroup_css_free(struct cgroup_subsys_state *css)
7104{
7105 struct task_group *tg = css_tg(css);
7106
7107 /*
7108 * Relies on the RCU grace period between css_released() and this.
7109 */
7110 sched_free_group(tg);
7111}
7112
7113/*
7114 * This is called before wake_up_new_task(), therefore we really only
7115 * have to set its group bits, all the other stuff does not apply.
7116 */
7117static void cpu_cgroup_fork(struct task_struct *task)
7118{
7119 struct rq_flags rf;
7120 struct rq *rq;
7121
7122 rq = task_rq_lock(task, &rf);
7123
7124 update_rq_clock(rq);
7125 sched_change_group(task, TASK_SET_GROUP);
7126
7127 task_rq_unlock(rq, task, &rf);
7128}
7129
7130static int cpu_cgroup_can_attach(struct cgroup_taskset *tset)
7131{
7132 struct task_struct *task;
7133 struct cgroup_subsys_state *css;
7134 int ret = 0;
7135
7136 cgroup_taskset_for_each(task, css, tset) {
7137#ifdef CONFIG_RT_GROUP_SCHED
7138 if (!sched_rt_can_attach(css_tg(css), task))
7139 return -EINVAL;
7140#endif
7141 /*
7142 * Serialize against wake_up_new_task() such that if its
7143 * running, we're sure to observe its full state.
7144 */
7145 raw_spin_lock_irq(&task->pi_lock);
7146 /*
7147 * Avoid calling sched_move_task() before wake_up_new_task()
7148 * has happened. This would lead to problems with PELT, due to
7149 * move wanting to detach+attach while we're not attached yet.
7150 */
7151 if (task->state == TASK_NEW)
7152 ret = -EINVAL;
7153 raw_spin_unlock_irq(&task->pi_lock);
7154
7155 if (ret)
7156 break;
7157 }
7158 return ret;
7159}
7160
7161static void cpu_cgroup_attach(struct cgroup_taskset *tset)
7162{
7163 struct task_struct *task;
7164 struct cgroup_subsys_state *css;
7165
7166 cgroup_taskset_for_each(task, css, tset)
7167 sched_move_task(task);
7168}
7169
7170#ifdef CONFIG_UCLAMP_TASK_GROUP
7171static void cpu_util_update_eff(struct cgroup_subsys_state *css)
7172{
7173 struct cgroup_subsys_state *top_css = css;
7174 struct uclamp_se *uc_parent = NULL;
7175 struct uclamp_se *uc_se = NULL;
7176 unsigned int eff[UCLAMP_CNT];
7177 enum uclamp_id clamp_id;
7178 unsigned int clamps;
7179
7180 css_for_each_descendant_pre(css, top_css) {
7181 uc_parent = css_tg(css)->parent
7182 ? css_tg(css)->parent->uclamp : NULL;
7183
7184 for_each_clamp_id(clamp_id) {
7185 /* Assume effective clamps matches requested clamps */
7186 eff[clamp_id] = css_tg(css)->uclamp_req[clamp_id].value;
7187 /* Cap effective clamps with parent's effective clamps */
7188 if (uc_parent &&
7189 eff[clamp_id] > uc_parent[clamp_id].value) {
7190 eff[clamp_id] = uc_parent[clamp_id].value;
7191 }
7192 }
7193 /* Ensure protection is always capped by limit */
7194 eff[UCLAMP_MIN] = min(eff[UCLAMP_MIN], eff[UCLAMP_MAX]);
7195
7196 /* Propagate most restrictive effective clamps */
7197 clamps = 0x0;
7198 uc_se = css_tg(css)->uclamp;
7199 for_each_clamp_id(clamp_id) {
7200 if (eff[clamp_id] == uc_se[clamp_id].value)
7201 continue;
7202 uc_se[clamp_id].value = eff[clamp_id];
7203 uc_se[clamp_id].bucket_id = uclamp_bucket_id(eff[clamp_id]);
7204 clamps |= (0x1 << clamp_id);
7205 }
7206 if (!clamps) {
7207 css = css_rightmost_descendant(css);
7208 continue;
7209 }
7210
7211 /* Immediately update descendants RUNNABLE tasks */
7212 uclamp_update_active_tasks(css, clamps);
7213 }
7214}
7215
7216/*
7217 * Integer 10^N with a given N exponent by casting to integer the literal "1eN"
7218 * C expression. Since there is no way to convert a macro argument (N) into a
7219 * character constant, use two levels of macros.
7220 */
7221#define _POW10(exp) ((unsigned int)1e##exp)
7222#define POW10(exp) _POW10(exp)
7223
7224struct uclamp_request {
7225#define UCLAMP_PERCENT_SHIFT 2
7226#define UCLAMP_PERCENT_SCALE (100 * POW10(UCLAMP_PERCENT_SHIFT))
7227 s64 percent;
7228 u64 util;
7229 int ret;
7230};
7231
7232static inline struct uclamp_request
7233capacity_from_percent(char *buf)
7234{
7235 struct uclamp_request req = {
7236 .percent = UCLAMP_PERCENT_SCALE,
7237 .util = SCHED_CAPACITY_SCALE,
7238 .ret = 0,
7239 };
7240
7241 buf = strim(buf);
7242 if (strcmp(buf, "max")) {
7243 req.ret = cgroup_parse_float(buf, UCLAMP_PERCENT_SHIFT,
7244 &req.percent);
7245 if (req.ret)
7246 return req;
7247 if (req.percent > UCLAMP_PERCENT_SCALE) {
7248 req.ret = -ERANGE;
7249 return req;
7250 }
7251
7252 req.util = req.percent << SCHED_CAPACITY_SHIFT;
7253 req.util = DIV_ROUND_CLOSEST_ULL(req.util, UCLAMP_PERCENT_SCALE);
7254 }
7255
7256 return req;
7257}
7258
7259static ssize_t cpu_uclamp_write(struct kernfs_open_file *of, char *buf,
7260 size_t nbytes, loff_t off,
7261 enum uclamp_id clamp_id)
7262{
7263 struct uclamp_request req;
7264 struct task_group *tg;
7265
7266 req = capacity_from_percent(buf);
7267 if (req.ret)
7268 return req.ret;
7269
7270 mutex_lock(&uclamp_mutex);
7271 rcu_read_lock();
7272
7273 tg = css_tg(of_css(of));
7274 if (tg->uclamp_req[clamp_id].value != req.util)
7275 uclamp_se_set(&tg->uclamp_req[clamp_id], req.util, false);
7276
7277 /*
7278 * Because of not recoverable conversion rounding we keep track of the
7279 * exact requested value
7280 */
7281 tg->uclamp_pct[clamp_id] = req.percent;
7282
7283 /* Update effective clamps to track the most restrictive value */
7284 cpu_util_update_eff(of_css(of));
7285
7286 rcu_read_unlock();
7287 mutex_unlock(&uclamp_mutex);
7288
7289 return nbytes;
7290}
7291
7292static ssize_t cpu_uclamp_min_write(struct kernfs_open_file *of,
7293 char *buf, size_t nbytes,
7294 loff_t off)
7295{
7296 return cpu_uclamp_write(of, buf, nbytes, off, UCLAMP_MIN);
7297}
7298
7299static ssize_t cpu_uclamp_max_write(struct kernfs_open_file *of,
7300 char *buf, size_t nbytes,
7301 loff_t off)
7302{
7303 return cpu_uclamp_write(of, buf, nbytes, off, UCLAMP_MAX);
7304}
7305
7306static inline void cpu_uclamp_print(struct seq_file *sf,
7307 enum uclamp_id clamp_id)
7308{
7309 struct task_group *tg;
7310 u64 util_clamp;
7311 u64 percent;
7312 u32 rem;
7313
7314 rcu_read_lock();
7315 tg = css_tg(seq_css(sf));
7316 util_clamp = tg->uclamp_req[clamp_id].value;
7317 rcu_read_unlock();
7318
7319 if (util_clamp == SCHED_CAPACITY_SCALE) {
7320 seq_puts(sf, "max\n");
7321 return;
7322 }
7323
7324 percent = tg->uclamp_pct[clamp_id];
7325 percent = div_u64_rem(percent, POW10(UCLAMP_PERCENT_SHIFT), &rem);
7326 seq_printf(sf, "%llu.%0*u\n", percent, UCLAMP_PERCENT_SHIFT, rem);
7327}
7328
7329static int cpu_uclamp_min_show(struct seq_file *sf, void *v)
7330{
7331 cpu_uclamp_print(sf, UCLAMP_MIN);
7332 return 0;
7333}
7334
7335static int cpu_uclamp_max_show(struct seq_file *sf, void *v)
7336{
7337 cpu_uclamp_print(sf, UCLAMP_MAX);
7338 return 0;
7339}
7340#endif /* CONFIG_UCLAMP_TASK_GROUP */
7341
7342#ifdef CONFIG_FAIR_GROUP_SCHED
7343static int cpu_shares_write_u64(struct cgroup_subsys_state *css,
7344 struct cftype *cftype, u64 shareval)
7345{
7346 if (shareval > scale_load_down(ULONG_MAX))
7347 shareval = MAX_SHARES;
7348 return sched_group_set_shares(css_tg(css), scale_load(shareval));
7349}
7350
7351static u64 cpu_shares_read_u64(struct cgroup_subsys_state *css,
7352 struct cftype *cft)
7353{
7354 struct task_group *tg = css_tg(css);
7355
7356 return (u64) scale_load_down(tg->shares);
7357}
7358
7359#ifdef CONFIG_CFS_BANDWIDTH
7360static DEFINE_MUTEX(cfs_constraints_mutex);
7361
7362const u64 max_cfs_quota_period = 1 * NSEC_PER_SEC; /* 1s */
7363static const u64 min_cfs_quota_period = 1 * NSEC_PER_MSEC; /* 1ms */
7364
7365static int __cfs_schedulable(struct task_group *tg, u64 period, u64 runtime);
7366
7367static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota)
7368{
7369 int i, ret = 0, runtime_enabled, runtime_was_enabled;
7370 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
7371
7372 if (tg == &root_task_group)
7373 return -EINVAL;
7374
7375 /*
7376 * Ensure we have at some amount of bandwidth every period. This is
7377 * to prevent reaching a state of large arrears when throttled via
7378 * entity_tick() resulting in prolonged exit starvation.
7379 */
7380 if (quota < min_cfs_quota_period || period < min_cfs_quota_period)
7381 return -EINVAL;
7382
7383 /*
7384 * Likewise, bound things on the otherside by preventing insane quota
7385 * periods. This also allows us to normalize in computing quota
7386 * feasibility.
7387 */
7388 if (period > max_cfs_quota_period)
7389 return -EINVAL;
7390
7391 /*
7392 * Prevent race between setting of cfs_rq->runtime_enabled and
7393 * unthrottle_offline_cfs_rqs().
7394 */
7395 get_online_cpus();
7396 mutex_lock(&cfs_constraints_mutex);
7397 ret = __cfs_schedulable(tg, period, quota);
7398 if (ret)
7399 goto out_unlock;
7400
7401 runtime_enabled = quota != RUNTIME_INF;
7402 runtime_was_enabled = cfs_b->quota != RUNTIME_INF;
7403 /*
7404 * If we need to toggle cfs_bandwidth_used, off->on must occur
7405 * before making related changes, and on->off must occur afterwards
7406 */
7407 if (runtime_enabled && !runtime_was_enabled)
7408 cfs_bandwidth_usage_inc();
7409 raw_spin_lock_irq(&cfs_b->lock);
7410 cfs_b->period = ns_to_ktime(period);
7411 cfs_b->quota = quota;
7412
7413 __refill_cfs_bandwidth_runtime(cfs_b);
7414
7415 /* Restart the period timer (if active) to handle new period expiry: */
7416 if (runtime_enabled)
7417 start_cfs_bandwidth(cfs_b);
7418
7419 raw_spin_unlock_irq(&cfs_b->lock);
7420
7421 for_each_online_cpu(i) {
7422 struct cfs_rq *cfs_rq = tg->cfs_rq[i];
7423 struct rq *rq = cfs_rq->rq;
7424 struct rq_flags rf;
7425
7426 rq_lock_irq(rq, &rf);
7427 cfs_rq->runtime_enabled = runtime_enabled;
7428 cfs_rq->runtime_remaining = 0;
7429
7430 if (cfs_rq->throttled)
7431 unthrottle_cfs_rq(cfs_rq);
7432 rq_unlock_irq(rq, &rf);
7433 }
7434 if (runtime_was_enabled && !runtime_enabled)
7435 cfs_bandwidth_usage_dec();
7436out_unlock:
7437 mutex_unlock(&cfs_constraints_mutex);
7438 put_online_cpus();
7439
7440 return ret;
7441}
7442
7443static int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us)
7444{
7445 u64 quota, period;
7446
7447 period = ktime_to_ns(tg->cfs_bandwidth.period);
7448 if (cfs_quota_us < 0)
7449 quota = RUNTIME_INF;
7450 else if ((u64)cfs_quota_us <= U64_MAX / NSEC_PER_USEC)
7451 quota = (u64)cfs_quota_us * NSEC_PER_USEC;
7452 else
7453 return -EINVAL;
7454
7455 return tg_set_cfs_bandwidth(tg, period, quota);
7456}
7457
7458static long tg_get_cfs_quota(struct task_group *tg)
7459{
7460 u64 quota_us;
7461
7462 if (tg->cfs_bandwidth.quota == RUNTIME_INF)
7463 return -1;
7464
7465 quota_us = tg->cfs_bandwidth.quota;
7466 do_div(quota_us, NSEC_PER_USEC);
7467
7468 return quota_us;
7469}
7470
7471static int tg_set_cfs_period(struct task_group *tg, long cfs_period_us)
7472{
7473 u64 quota, period;
7474
7475 if ((u64)cfs_period_us > U64_MAX / NSEC_PER_USEC)
7476 return -EINVAL;
7477
7478 period = (u64)cfs_period_us * NSEC_PER_USEC;
7479 quota = tg->cfs_bandwidth.quota;
7480
7481 return tg_set_cfs_bandwidth(tg, period, quota);
7482}
7483
7484static long tg_get_cfs_period(struct task_group *tg)
7485{
7486 u64 cfs_period_us;
7487
7488 cfs_period_us = ktime_to_ns(tg->cfs_bandwidth.period);
7489 do_div(cfs_period_us, NSEC_PER_USEC);
7490
7491 return cfs_period_us;
7492}
7493
7494static s64 cpu_cfs_quota_read_s64(struct cgroup_subsys_state *css,
7495 struct cftype *cft)
7496{
7497 return tg_get_cfs_quota(css_tg(css));
7498}
7499
7500static int cpu_cfs_quota_write_s64(struct cgroup_subsys_state *css,
7501 struct cftype *cftype, s64 cfs_quota_us)
7502{
7503 return tg_set_cfs_quota(css_tg(css), cfs_quota_us);
7504}
7505
7506static u64 cpu_cfs_period_read_u64(struct cgroup_subsys_state *css,
7507 struct cftype *cft)
7508{
7509 return tg_get_cfs_period(css_tg(css));
7510}
7511
7512static int cpu_cfs_period_write_u64(struct cgroup_subsys_state *css,
7513 struct cftype *cftype, u64 cfs_period_us)
7514{
7515 return tg_set_cfs_period(css_tg(css), cfs_period_us);
7516}
7517
7518struct cfs_schedulable_data {
7519 struct task_group *tg;
7520 u64 period, quota;
7521};
7522
7523/*
7524 * normalize group quota/period to be quota/max_period
7525 * note: units are usecs
7526 */
7527static u64 normalize_cfs_quota(struct task_group *tg,
7528 struct cfs_schedulable_data *d)
7529{
7530 u64 quota, period;
7531
7532 if (tg == d->tg) {
7533 period = d->period;
7534 quota = d->quota;
7535 } else {
7536 period = tg_get_cfs_period(tg);
7537 quota = tg_get_cfs_quota(tg);
7538 }
7539
7540 /* note: these should typically be equivalent */
7541 if (quota == RUNTIME_INF || quota == -1)
7542 return RUNTIME_INF;
7543
7544 return to_ratio(period, quota);
7545}
7546
7547static int tg_cfs_schedulable_down(struct task_group *tg, void *data)
7548{
7549 struct cfs_schedulable_data *d = data;
7550 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
7551 s64 quota = 0, parent_quota = -1;
7552
7553 if (!tg->parent) {
7554 quota = RUNTIME_INF;
7555 } else {
7556 struct cfs_bandwidth *parent_b = &tg->parent->cfs_bandwidth;
7557
7558 quota = normalize_cfs_quota(tg, d);
7559 parent_quota = parent_b->hierarchical_quota;
7560
7561 /*
7562 * Ensure max(child_quota) <= parent_quota. On cgroup2,
7563 * always take the min. On cgroup1, only inherit when no
7564 * limit is set:
7565 */
7566 if (cgroup_subsys_on_dfl(cpu_cgrp_subsys)) {
7567 quota = min(quota, parent_quota);
7568 } else {
7569 if (quota == RUNTIME_INF)
7570 quota = parent_quota;
7571 else if (parent_quota != RUNTIME_INF && quota > parent_quota)
7572 return -EINVAL;
7573 }
7574 }
7575 cfs_b->hierarchical_quota = quota;
7576
7577 return 0;
7578}
7579
7580static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota)
7581{
7582 int ret;
7583 struct cfs_schedulable_data data = {
7584 .tg = tg,
7585 .period = period,
7586 .quota = quota,
7587 };
7588
7589 if (quota != RUNTIME_INF) {
7590 do_div(data.period, NSEC_PER_USEC);
7591 do_div(data.quota, NSEC_PER_USEC);
7592 }
7593
7594 rcu_read_lock();
7595 ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data);
7596 rcu_read_unlock();
7597
7598 return ret;
7599}
7600
7601static int cpu_cfs_stat_show(struct seq_file *sf, void *v)
7602{
7603 struct task_group *tg = css_tg(seq_css(sf));
7604 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
7605
7606 seq_printf(sf, "nr_periods %d\n", cfs_b->nr_periods);
7607 seq_printf(sf, "nr_throttled %d\n", cfs_b->nr_throttled);
7608 seq_printf(sf, "throttled_time %llu\n", cfs_b->throttled_time);
7609
7610 if (schedstat_enabled() && tg != &root_task_group) {
7611 u64 ws = 0;
7612 int i;
7613
7614 for_each_possible_cpu(i)
7615 ws += schedstat_val(tg->se[i]->statistics.wait_sum);
7616
7617 seq_printf(sf, "wait_sum %llu\n", ws);
7618 }
7619
7620 return 0;
7621}
7622#endif /* CONFIG_CFS_BANDWIDTH */
7623#endif /* CONFIG_FAIR_GROUP_SCHED */
7624
7625#ifdef CONFIG_RT_GROUP_SCHED
7626static int cpu_rt_runtime_write(struct cgroup_subsys_state *css,
7627 struct cftype *cft, s64 val)
7628{
7629 return sched_group_set_rt_runtime(css_tg(css), val);
7630}
7631
7632static s64 cpu_rt_runtime_read(struct cgroup_subsys_state *css,
7633 struct cftype *cft)
7634{
7635 return sched_group_rt_runtime(css_tg(css));
7636}
7637
7638static int cpu_rt_period_write_uint(struct cgroup_subsys_state *css,
7639 struct cftype *cftype, u64 rt_period_us)
7640{
7641 return sched_group_set_rt_period(css_tg(css), rt_period_us);
7642}
7643
7644static u64 cpu_rt_period_read_uint(struct cgroup_subsys_state *css,
7645 struct cftype *cft)
7646{
7647 return sched_group_rt_period(css_tg(css));
7648}
7649#endif /* CONFIG_RT_GROUP_SCHED */
7650
7651static struct cftype cpu_legacy_files[] = {
7652#ifdef CONFIG_FAIR_GROUP_SCHED
7653 {
7654 .name = "shares",
7655 .read_u64 = cpu_shares_read_u64,
7656 .write_u64 = cpu_shares_write_u64,
7657 },
7658#endif
7659#ifdef CONFIG_CFS_BANDWIDTH
7660 {
7661 .name = "cfs_quota_us",
7662 .read_s64 = cpu_cfs_quota_read_s64,
7663 .write_s64 = cpu_cfs_quota_write_s64,
7664 },
7665 {
7666 .name = "cfs_period_us",
7667 .read_u64 = cpu_cfs_period_read_u64,
7668 .write_u64 = cpu_cfs_period_write_u64,
7669 },
7670 {
7671 .name = "stat",
7672 .seq_show = cpu_cfs_stat_show,
7673 },
7674#endif
7675#ifdef CONFIG_RT_GROUP_SCHED
7676 {
7677 .name = "rt_runtime_us",
7678 .read_s64 = cpu_rt_runtime_read,
7679 .write_s64 = cpu_rt_runtime_write,
7680 },
7681 {
7682 .name = "rt_period_us",
7683 .read_u64 = cpu_rt_period_read_uint,
7684 .write_u64 = cpu_rt_period_write_uint,
7685 },
7686#endif
7687#ifdef CONFIG_UCLAMP_TASK_GROUP
7688 {
7689 .name = "uclamp.min",
7690 .flags = CFTYPE_NOT_ON_ROOT,
7691 .seq_show = cpu_uclamp_min_show,
7692 .write = cpu_uclamp_min_write,
7693 },
7694 {
7695 .name = "uclamp.max",
7696 .flags = CFTYPE_NOT_ON_ROOT,
7697 .seq_show = cpu_uclamp_max_show,
7698 .write = cpu_uclamp_max_write,
7699 },
7700#endif
7701 { } /* Terminate */
7702};
7703
7704static int cpu_extra_stat_show(struct seq_file *sf,
7705 struct cgroup_subsys_state *css)
7706{
7707#ifdef CONFIG_CFS_BANDWIDTH
7708 {
7709 struct task_group *tg = css_tg(css);
7710 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
7711 u64 throttled_usec;
7712
7713 throttled_usec = cfs_b->throttled_time;
7714 do_div(throttled_usec, NSEC_PER_USEC);
7715
7716 seq_printf(sf, "nr_periods %d\n"
7717 "nr_throttled %d\n"
7718 "throttled_usec %llu\n",
7719 cfs_b->nr_periods, cfs_b->nr_throttled,
7720 throttled_usec);
7721 }
7722#endif
7723 return 0;
7724}
7725
7726#ifdef CONFIG_FAIR_GROUP_SCHED
7727static u64 cpu_weight_read_u64(struct cgroup_subsys_state *css,
7728 struct cftype *cft)
7729{
7730 struct task_group *tg = css_tg(css);
7731 u64 weight = scale_load_down(tg->shares);
7732
7733 return DIV_ROUND_CLOSEST_ULL(weight * CGROUP_WEIGHT_DFL, 1024);
7734}
7735
7736static int cpu_weight_write_u64(struct cgroup_subsys_state *css,
7737 struct cftype *cft, u64 weight)
7738{
7739 /*
7740 * cgroup weight knobs should use the common MIN, DFL and MAX
7741 * values which are 1, 100 and 10000 respectively. While it loses
7742 * a bit of range on both ends, it maps pretty well onto the shares
7743 * value used by scheduler and the round-trip conversions preserve
7744 * the original value over the entire range.
7745 */
7746 if (weight < CGROUP_WEIGHT_MIN || weight > CGROUP_WEIGHT_MAX)
7747 return -ERANGE;
7748
7749 weight = DIV_ROUND_CLOSEST_ULL(weight * 1024, CGROUP_WEIGHT_DFL);
7750
7751 return sched_group_set_shares(css_tg(css), scale_load(weight));
7752}
7753
7754static s64 cpu_weight_nice_read_s64(struct cgroup_subsys_state *css,
7755 struct cftype *cft)
7756{
7757 unsigned long weight = scale_load_down(css_tg(css)->shares);
7758 int last_delta = INT_MAX;
7759 int prio, delta;
7760
7761 /* find the closest nice value to the current weight */
7762 for (prio = 0; prio < ARRAY_SIZE(sched_prio_to_weight); prio++) {
7763 delta = abs(sched_prio_to_weight[prio] - weight);
7764 if (delta >= last_delta)
7765 break;
7766 last_delta = delta;
7767 }
7768
7769 return PRIO_TO_NICE(prio - 1 + MAX_RT_PRIO);
7770}
7771
7772static int cpu_weight_nice_write_s64(struct cgroup_subsys_state *css,
7773 struct cftype *cft, s64 nice)
7774{
7775 unsigned long weight;
7776 int idx;
7777
7778 if (nice < MIN_NICE || nice > MAX_NICE)
7779 return -ERANGE;
7780
7781 idx = NICE_TO_PRIO(nice) - MAX_RT_PRIO;
7782 idx = array_index_nospec(idx, 40);
7783 weight = sched_prio_to_weight[idx];
7784
7785 return sched_group_set_shares(css_tg(css), scale_load(weight));
7786}
7787#endif
7788
7789static void __maybe_unused cpu_period_quota_print(struct seq_file *sf,
7790 long period, long quota)
7791{
7792 if (quota < 0)
7793 seq_puts(sf, "max");
7794 else
7795 seq_printf(sf, "%ld", quota);
7796
7797 seq_printf(sf, " %ld\n", period);
7798}
7799
7800/* caller should put the current value in *@periodp before calling */
7801static int __maybe_unused cpu_period_quota_parse(char *buf,
7802 u64 *periodp, u64 *quotap)
7803{
7804 char tok[21]; /* U64_MAX */
7805
7806 if (sscanf(buf, "%20s %llu", tok, periodp) < 1)
7807 return -EINVAL;
7808
7809 *periodp *= NSEC_PER_USEC;
7810
7811 if (sscanf(tok, "%llu", quotap))
7812 *quotap *= NSEC_PER_USEC;
7813 else if (!strcmp(tok, "max"))
7814 *quotap = RUNTIME_INF;
7815 else
7816 return -EINVAL;
7817
7818 return 0;
7819}
7820
7821#ifdef CONFIG_CFS_BANDWIDTH
7822static int cpu_max_show(struct seq_file *sf, void *v)
7823{
7824 struct task_group *tg = css_tg(seq_css(sf));
7825
7826 cpu_period_quota_print(sf, tg_get_cfs_period(tg), tg_get_cfs_quota(tg));
7827 return 0;
7828}
7829
7830static ssize_t cpu_max_write(struct kernfs_open_file *of,
7831 char *buf, size_t nbytes, loff_t off)
7832{
7833 struct task_group *tg = css_tg(of_css(of));
7834 u64 period = tg_get_cfs_period(tg);
7835 u64 quota;
7836 int ret;
7837
7838 ret = cpu_period_quota_parse(buf, &period, "a);
7839 if (!ret)
7840 ret = tg_set_cfs_bandwidth(tg, period, quota);
7841 return ret ?: nbytes;
7842}
7843#endif
7844
7845static struct cftype cpu_files[] = {
7846#ifdef CONFIG_FAIR_GROUP_SCHED
7847 {
7848 .name = "weight",
7849 .flags = CFTYPE_NOT_ON_ROOT,
7850 .read_u64 = cpu_weight_read_u64,
7851 .write_u64 = cpu_weight_write_u64,
7852 },
7853 {
7854 .name = "weight.nice",
7855 .flags = CFTYPE_NOT_ON_ROOT,
7856 .read_s64 = cpu_weight_nice_read_s64,
7857 .write_s64 = cpu_weight_nice_write_s64,
7858 },
7859#endif
7860#ifdef CONFIG_CFS_BANDWIDTH
7861 {
7862 .name = "max",
7863 .flags = CFTYPE_NOT_ON_ROOT,
7864 .seq_show = cpu_max_show,
7865 .write = cpu_max_write,
7866 },
7867#endif
7868#ifdef CONFIG_UCLAMP_TASK_GROUP
7869 {
7870 .name = "uclamp.min",
7871 .flags = CFTYPE_NOT_ON_ROOT,
7872 .seq_show = cpu_uclamp_min_show,
7873 .write = cpu_uclamp_min_write,
7874 },
7875 {
7876 .name = "uclamp.max",
7877 .flags = CFTYPE_NOT_ON_ROOT,
7878 .seq_show = cpu_uclamp_max_show,
7879 .write = cpu_uclamp_max_write,
7880 },
7881#endif
7882 { } /* terminate */
7883};
7884
7885struct cgroup_subsys cpu_cgrp_subsys = {
7886 .css_alloc = cpu_cgroup_css_alloc,
7887 .css_online = cpu_cgroup_css_online,
7888 .css_released = cpu_cgroup_css_released,
7889 .css_free = cpu_cgroup_css_free,
7890 .css_extra_stat_show = cpu_extra_stat_show,
7891 .fork = cpu_cgroup_fork,
7892 .can_attach = cpu_cgroup_can_attach,
7893 .attach = cpu_cgroup_attach,
7894 .legacy_cftypes = cpu_legacy_files,
7895 .dfl_cftypes = cpu_files,
7896 .early_init = true,
7897 .threaded = true,
7898};
7899
7900#endif /* CONFIG_CGROUP_SCHED */
7901
7902void dump_cpu_task(int cpu)
7903{
7904 pr_info("Task dump for CPU %d:\n", cpu);
7905 sched_show_task(cpu_curr(cpu));
7906}
7907
7908/*
7909 * Nice levels are multiplicative, with a gentle 10% change for every
7910 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
7911 * nice 1, it will get ~10% less CPU time than another CPU-bound task
7912 * that remained on nice 0.
7913 *
7914 * The "10% effect" is relative and cumulative: from _any_ nice level,
7915 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
7916 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
7917 * If a task goes up by ~10% and another task goes down by ~10% then
7918 * the relative distance between them is ~25%.)
7919 */
7920const int sched_prio_to_weight[40] = {
7921 /* -20 */ 88761, 71755, 56483, 46273, 36291,
7922 /* -15 */ 29154, 23254, 18705, 14949, 11916,
7923 /* -10 */ 9548, 7620, 6100, 4904, 3906,
7924 /* -5 */ 3121, 2501, 1991, 1586, 1277,
7925 /* 0 */ 1024, 820, 655, 526, 423,
7926 /* 5 */ 335, 272, 215, 172, 137,
7927 /* 10 */ 110, 87, 70, 56, 45,
7928 /* 15 */ 36, 29, 23, 18, 15,
7929};
7930
7931/*
7932 * Inverse (2^32/x) values of the sched_prio_to_weight[] array, precalculated.
7933 *
7934 * In cases where the weight does not change often, we can use the
7935 * precalculated inverse to speed up arithmetics by turning divisions
7936 * into multiplications:
7937 */
7938const u32 sched_prio_to_wmult[40] = {
7939 /* -20 */ 48388, 59856, 76040, 92818, 118348,
7940 /* -15 */ 147320, 184698, 229616, 287308, 360437,
7941 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
7942 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
7943 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
7944 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
7945 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
7946 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
7947};
7948
7949#undef CREATE_TRACE_POINTS