Loading...
1/*
2 * Real-Time Scheduling Class (mapped to the SCHED_FIFO and SCHED_RR
3 * policies)
4 */
5
6#include "sched.h"
7
8#include <linux/slab.h>
9
10static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun);
11
12struct rt_bandwidth def_rt_bandwidth;
13
14static enum hrtimer_restart sched_rt_period_timer(struct hrtimer *timer)
15{
16 struct rt_bandwidth *rt_b =
17 container_of(timer, struct rt_bandwidth, rt_period_timer);
18 ktime_t now;
19 int overrun;
20 int idle = 0;
21
22 for (;;) {
23 now = hrtimer_cb_get_time(timer);
24 overrun = hrtimer_forward(timer, now, rt_b->rt_period);
25
26 if (!overrun)
27 break;
28
29 idle = do_sched_rt_period_timer(rt_b, overrun);
30 }
31
32 return idle ? HRTIMER_NORESTART : HRTIMER_RESTART;
33}
34
35void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime)
36{
37 rt_b->rt_period = ns_to_ktime(period);
38 rt_b->rt_runtime = runtime;
39
40 raw_spin_lock_init(&rt_b->rt_runtime_lock);
41
42 hrtimer_init(&rt_b->rt_period_timer,
43 CLOCK_MONOTONIC, HRTIMER_MODE_REL);
44 rt_b->rt_period_timer.function = sched_rt_period_timer;
45}
46
47static void start_rt_bandwidth(struct rt_bandwidth *rt_b)
48{
49 if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)
50 return;
51
52 if (hrtimer_active(&rt_b->rt_period_timer))
53 return;
54
55 raw_spin_lock(&rt_b->rt_runtime_lock);
56 start_bandwidth_timer(&rt_b->rt_period_timer, rt_b->rt_period);
57 raw_spin_unlock(&rt_b->rt_runtime_lock);
58}
59
60void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
61{
62 struct rt_prio_array *array;
63 int i;
64
65 array = &rt_rq->active;
66 for (i = 0; i < MAX_RT_PRIO; i++) {
67 INIT_LIST_HEAD(array->queue + i);
68 __clear_bit(i, array->bitmap);
69 }
70 /* delimiter for bitsearch: */
71 __set_bit(MAX_RT_PRIO, array->bitmap);
72
73#if defined CONFIG_SMP
74 rt_rq->highest_prio.curr = MAX_RT_PRIO;
75 rt_rq->highest_prio.next = MAX_RT_PRIO;
76 rt_rq->rt_nr_migratory = 0;
77 rt_rq->overloaded = 0;
78 plist_head_init(&rt_rq->pushable_tasks);
79#endif
80
81 rt_rq->rt_time = 0;
82 rt_rq->rt_throttled = 0;
83 rt_rq->rt_runtime = 0;
84 raw_spin_lock_init(&rt_rq->rt_runtime_lock);
85}
86
87#ifdef CONFIG_RT_GROUP_SCHED
88static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b)
89{
90 hrtimer_cancel(&rt_b->rt_period_timer);
91}
92
93#define rt_entity_is_task(rt_se) (!(rt_se)->my_q)
94
95static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
96{
97#ifdef CONFIG_SCHED_DEBUG
98 WARN_ON_ONCE(!rt_entity_is_task(rt_se));
99#endif
100 return container_of(rt_se, struct task_struct, rt);
101}
102
103static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
104{
105 return rt_rq->rq;
106}
107
108static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
109{
110 return rt_se->rt_rq;
111}
112
113void free_rt_sched_group(struct task_group *tg)
114{
115 int i;
116
117 if (tg->rt_se)
118 destroy_rt_bandwidth(&tg->rt_bandwidth);
119
120 for_each_possible_cpu(i) {
121 if (tg->rt_rq)
122 kfree(tg->rt_rq[i]);
123 if (tg->rt_se)
124 kfree(tg->rt_se[i]);
125 }
126
127 kfree(tg->rt_rq);
128 kfree(tg->rt_se);
129}
130
131void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
132 struct sched_rt_entity *rt_se, int cpu,
133 struct sched_rt_entity *parent)
134{
135 struct rq *rq = cpu_rq(cpu);
136
137 rt_rq->highest_prio.curr = MAX_RT_PRIO;
138 rt_rq->rt_nr_boosted = 0;
139 rt_rq->rq = rq;
140 rt_rq->tg = tg;
141
142 tg->rt_rq[cpu] = rt_rq;
143 tg->rt_se[cpu] = rt_se;
144
145 if (!rt_se)
146 return;
147
148 if (!parent)
149 rt_se->rt_rq = &rq->rt;
150 else
151 rt_se->rt_rq = parent->my_q;
152
153 rt_se->my_q = rt_rq;
154 rt_se->parent = parent;
155 INIT_LIST_HEAD(&rt_se->run_list);
156}
157
158int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
159{
160 struct rt_rq *rt_rq;
161 struct sched_rt_entity *rt_se;
162 int i;
163
164 tg->rt_rq = kzalloc(sizeof(rt_rq) * nr_cpu_ids, GFP_KERNEL);
165 if (!tg->rt_rq)
166 goto err;
167 tg->rt_se = kzalloc(sizeof(rt_se) * nr_cpu_ids, GFP_KERNEL);
168 if (!tg->rt_se)
169 goto err;
170
171 init_rt_bandwidth(&tg->rt_bandwidth,
172 ktime_to_ns(def_rt_bandwidth.rt_period), 0);
173
174 for_each_possible_cpu(i) {
175 rt_rq = kzalloc_node(sizeof(struct rt_rq),
176 GFP_KERNEL, cpu_to_node(i));
177 if (!rt_rq)
178 goto err;
179
180 rt_se = kzalloc_node(sizeof(struct sched_rt_entity),
181 GFP_KERNEL, cpu_to_node(i));
182 if (!rt_se)
183 goto err_free_rq;
184
185 init_rt_rq(rt_rq, cpu_rq(i));
186 rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime;
187 init_tg_rt_entry(tg, rt_rq, rt_se, i, parent->rt_se[i]);
188 }
189
190 return 1;
191
192err_free_rq:
193 kfree(rt_rq);
194err:
195 return 0;
196}
197
198#else /* CONFIG_RT_GROUP_SCHED */
199
200#define rt_entity_is_task(rt_se) (1)
201
202static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
203{
204 return container_of(rt_se, struct task_struct, rt);
205}
206
207static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
208{
209 return container_of(rt_rq, struct rq, rt);
210}
211
212static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
213{
214 struct task_struct *p = rt_task_of(rt_se);
215 struct rq *rq = task_rq(p);
216
217 return &rq->rt;
218}
219
220void free_rt_sched_group(struct task_group *tg) { }
221
222int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
223{
224 return 1;
225}
226#endif /* CONFIG_RT_GROUP_SCHED */
227
228#ifdef CONFIG_SMP
229
230static inline int rt_overloaded(struct rq *rq)
231{
232 return atomic_read(&rq->rd->rto_count);
233}
234
235static inline void rt_set_overload(struct rq *rq)
236{
237 if (!rq->online)
238 return;
239
240 cpumask_set_cpu(rq->cpu, rq->rd->rto_mask);
241 /*
242 * Make sure the mask is visible before we set
243 * the overload count. That is checked to determine
244 * if we should look at the mask. It would be a shame
245 * if we looked at the mask, but the mask was not
246 * updated yet.
247 */
248 wmb();
249 atomic_inc(&rq->rd->rto_count);
250}
251
252static inline void rt_clear_overload(struct rq *rq)
253{
254 if (!rq->online)
255 return;
256
257 /* the order here really doesn't matter */
258 atomic_dec(&rq->rd->rto_count);
259 cpumask_clear_cpu(rq->cpu, rq->rd->rto_mask);
260}
261
262static void update_rt_migration(struct rt_rq *rt_rq)
263{
264 if (rt_rq->rt_nr_migratory && rt_rq->rt_nr_total > 1) {
265 if (!rt_rq->overloaded) {
266 rt_set_overload(rq_of_rt_rq(rt_rq));
267 rt_rq->overloaded = 1;
268 }
269 } else if (rt_rq->overloaded) {
270 rt_clear_overload(rq_of_rt_rq(rt_rq));
271 rt_rq->overloaded = 0;
272 }
273}
274
275static void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
276{
277 struct task_struct *p;
278
279 if (!rt_entity_is_task(rt_se))
280 return;
281
282 p = rt_task_of(rt_se);
283 rt_rq = &rq_of_rt_rq(rt_rq)->rt;
284
285 rt_rq->rt_nr_total++;
286 if (p->nr_cpus_allowed > 1)
287 rt_rq->rt_nr_migratory++;
288
289 update_rt_migration(rt_rq);
290}
291
292static void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
293{
294 struct task_struct *p;
295
296 if (!rt_entity_is_task(rt_se))
297 return;
298
299 p = rt_task_of(rt_se);
300 rt_rq = &rq_of_rt_rq(rt_rq)->rt;
301
302 rt_rq->rt_nr_total--;
303 if (p->nr_cpus_allowed > 1)
304 rt_rq->rt_nr_migratory--;
305
306 update_rt_migration(rt_rq);
307}
308
309static inline int has_pushable_tasks(struct rq *rq)
310{
311 return !plist_head_empty(&rq->rt.pushable_tasks);
312}
313
314static void enqueue_pushable_task(struct rq *rq, struct task_struct *p)
315{
316 plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks);
317 plist_node_init(&p->pushable_tasks, p->prio);
318 plist_add(&p->pushable_tasks, &rq->rt.pushable_tasks);
319
320 /* Update the highest prio pushable task */
321 if (p->prio < rq->rt.highest_prio.next)
322 rq->rt.highest_prio.next = p->prio;
323}
324
325static void dequeue_pushable_task(struct rq *rq, struct task_struct *p)
326{
327 plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks);
328
329 /* Update the new highest prio pushable task */
330 if (has_pushable_tasks(rq)) {
331 p = plist_first_entry(&rq->rt.pushable_tasks,
332 struct task_struct, pushable_tasks);
333 rq->rt.highest_prio.next = p->prio;
334 } else
335 rq->rt.highest_prio.next = MAX_RT_PRIO;
336}
337
338#else
339
340static inline void enqueue_pushable_task(struct rq *rq, struct task_struct *p)
341{
342}
343
344static inline void dequeue_pushable_task(struct rq *rq, struct task_struct *p)
345{
346}
347
348static inline
349void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
350{
351}
352
353static inline
354void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
355{
356}
357
358#endif /* CONFIG_SMP */
359
360static inline int on_rt_rq(struct sched_rt_entity *rt_se)
361{
362 return !list_empty(&rt_se->run_list);
363}
364
365#ifdef CONFIG_RT_GROUP_SCHED
366
367static inline u64 sched_rt_runtime(struct rt_rq *rt_rq)
368{
369 if (!rt_rq->tg)
370 return RUNTIME_INF;
371
372 return rt_rq->rt_runtime;
373}
374
375static inline u64 sched_rt_period(struct rt_rq *rt_rq)
376{
377 return ktime_to_ns(rt_rq->tg->rt_bandwidth.rt_period);
378}
379
380typedef struct task_group *rt_rq_iter_t;
381
382static inline struct task_group *next_task_group(struct task_group *tg)
383{
384 do {
385 tg = list_entry_rcu(tg->list.next,
386 typeof(struct task_group), list);
387 } while (&tg->list != &task_groups && task_group_is_autogroup(tg));
388
389 if (&tg->list == &task_groups)
390 tg = NULL;
391
392 return tg;
393}
394
395#define for_each_rt_rq(rt_rq, iter, rq) \
396 for (iter = container_of(&task_groups, typeof(*iter), list); \
397 (iter = next_task_group(iter)) && \
398 (rt_rq = iter->rt_rq[cpu_of(rq)]);)
399
400static inline void list_add_leaf_rt_rq(struct rt_rq *rt_rq)
401{
402 list_add_rcu(&rt_rq->leaf_rt_rq_list,
403 &rq_of_rt_rq(rt_rq)->leaf_rt_rq_list);
404}
405
406static inline void list_del_leaf_rt_rq(struct rt_rq *rt_rq)
407{
408 list_del_rcu(&rt_rq->leaf_rt_rq_list);
409}
410
411#define for_each_leaf_rt_rq(rt_rq, rq) \
412 list_for_each_entry_rcu(rt_rq, &rq->leaf_rt_rq_list, leaf_rt_rq_list)
413
414#define for_each_sched_rt_entity(rt_se) \
415 for (; rt_se; rt_se = rt_se->parent)
416
417static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
418{
419 return rt_se->my_q;
420}
421
422static void enqueue_rt_entity(struct sched_rt_entity *rt_se, bool head);
423static void dequeue_rt_entity(struct sched_rt_entity *rt_se);
424
425static void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
426{
427 struct task_struct *curr = rq_of_rt_rq(rt_rq)->curr;
428 struct sched_rt_entity *rt_se;
429
430 int cpu = cpu_of(rq_of_rt_rq(rt_rq));
431
432 rt_se = rt_rq->tg->rt_se[cpu];
433
434 if (rt_rq->rt_nr_running) {
435 if (rt_se && !on_rt_rq(rt_se))
436 enqueue_rt_entity(rt_se, false);
437 if (rt_rq->highest_prio.curr < curr->prio)
438 resched_task(curr);
439 }
440}
441
442static void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
443{
444 struct sched_rt_entity *rt_se;
445 int cpu = cpu_of(rq_of_rt_rq(rt_rq));
446
447 rt_se = rt_rq->tg->rt_se[cpu];
448
449 if (rt_se && on_rt_rq(rt_se))
450 dequeue_rt_entity(rt_se);
451}
452
453static inline int rt_rq_throttled(struct rt_rq *rt_rq)
454{
455 return rt_rq->rt_throttled && !rt_rq->rt_nr_boosted;
456}
457
458static int rt_se_boosted(struct sched_rt_entity *rt_se)
459{
460 struct rt_rq *rt_rq = group_rt_rq(rt_se);
461 struct task_struct *p;
462
463 if (rt_rq)
464 return !!rt_rq->rt_nr_boosted;
465
466 p = rt_task_of(rt_se);
467 return p->prio != p->normal_prio;
468}
469
470#ifdef CONFIG_SMP
471static inline const struct cpumask *sched_rt_period_mask(void)
472{
473 return cpu_rq(smp_processor_id())->rd->span;
474}
475#else
476static inline const struct cpumask *sched_rt_period_mask(void)
477{
478 return cpu_online_mask;
479}
480#endif
481
482static inline
483struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu)
484{
485 return container_of(rt_b, struct task_group, rt_bandwidth)->rt_rq[cpu];
486}
487
488static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
489{
490 return &rt_rq->tg->rt_bandwidth;
491}
492
493#else /* !CONFIG_RT_GROUP_SCHED */
494
495static inline u64 sched_rt_runtime(struct rt_rq *rt_rq)
496{
497 return rt_rq->rt_runtime;
498}
499
500static inline u64 sched_rt_period(struct rt_rq *rt_rq)
501{
502 return ktime_to_ns(def_rt_bandwidth.rt_period);
503}
504
505typedef struct rt_rq *rt_rq_iter_t;
506
507#define for_each_rt_rq(rt_rq, iter, rq) \
508 for ((void) iter, rt_rq = &rq->rt; rt_rq; rt_rq = NULL)
509
510static inline void list_add_leaf_rt_rq(struct rt_rq *rt_rq)
511{
512}
513
514static inline void list_del_leaf_rt_rq(struct rt_rq *rt_rq)
515{
516}
517
518#define for_each_leaf_rt_rq(rt_rq, rq) \
519 for (rt_rq = &rq->rt; rt_rq; rt_rq = NULL)
520
521#define for_each_sched_rt_entity(rt_se) \
522 for (; rt_se; rt_se = NULL)
523
524static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
525{
526 return NULL;
527}
528
529static inline void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
530{
531 if (rt_rq->rt_nr_running)
532 resched_task(rq_of_rt_rq(rt_rq)->curr);
533}
534
535static inline void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
536{
537}
538
539static inline int rt_rq_throttled(struct rt_rq *rt_rq)
540{
541 return rt_rq->rt_throttled;
542}
543
544static inline const struct cpumask *sched_rt_period_mask(void)
545{
546 return cpu_online_mask;
547}
548
549static inline
550struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu)
551{
552 return &cpu_rq(cpu)->rt;
553}
554
555static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
556{
557 return &def_rt_bandwidth;
558}
559
560#endif /* CONFIG_RT_GROUP_SCHED */
561
562#ifdef CONFIG_SMP
563/*
564 * We ran out of runtime, see if we can borrow some from our neighbours.
565 */
566static int do_balance_runtime(struct rt_rq *rt_rq)
567{
568 struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
569 struct root_domain *rd = cpu_rq(smp_processor_id())->rd;
570 int i, weight, more = 0;
571 u64 rt_period;
572
573 weight = cpumask_weight(rd->span);
574
575 raw_spin_lock(&rt_b->rt_runtime_lock);
576 rt_period = ktime_to_ns(rt_b->rt_period);
577 for_each_cpu(i, rd->span) {
578 struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
579 s64 diff;
580
581 if (iter == rt_rq)
582 continue;
583
584 raw_spin_lock(&iter->rt_runtime_lock);
585 /*
586 * Either all rqs have inf runtime and there's nothing to steal
587 * or __disable_runtime() below sets a specific rq to inf to
588 * indicate its been disabled and disalow stealing.
589 */
590 if (iter->rt_runtime == RUNTIME_INF)
591 goto next;
592
593 /*
594 * From runqueues with spare time, take 1/n part of their
595 * spare time, but no more than our period.
596 */
597 diff = iter->rt_runtime - iter->rt_time;
598 if (diff > 0) {
599 diff = div_u64((u64)diff, weight);
600 if (rt_rq->rt_runtime + diff > rt_period)
601 diff = rt_period - rt_rq->rt_runtime;
602 iter->rt_runtime -= diff;
603 rt_rq->rt_runtime += diff;
604 more = 1;
605 if (rt_rq->rt_runtime == rt_period) {
606 raw_spin_unlock(&iter->rt_runtime_lock);
607 break;
608 }
609 }
610next:
611 raw_spin_unlock(&iter->rt_runtime_lock);
612 }
613 raw_spin_unlock(&rt_b->rt_runtime_lock);
614
615 return more;
616}
617
618/*
619 * Ensure this RQ takes back all the runtime it lend to its neighbours.
620 */
621static void __disable_runtime(struct rq *rq)
622{
623 struct root_domain *rd = rq->rd;
624 rt_rq_iter_t iter;
625 struct rt_rq *rt_rq;
626
627 if (unlikely(!scheduler_running))
628 return;
629
630 for_each_rt_rq(rt_rq, iter, rq) {
631 struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
632 s64 want;
633 int i;
634
635 raw_spin_lock(&rt_b->rt_runtime_lock);
636 raw_spin_lock(&rt_rq->rt_runtime_lock);
637 /*
638 * Either we're all inf and nobody needs to borrow, or we're
639 * already disabled and thus have nothing to do, or we have
640 * exactly the right amount of runtime to take out.
641 */
642 if (rt_rq->rt_runtime == RUNTIME_INF ||
643 rt_rq->rt_runtime == rt_b->rt_runtime)
644 goto balanced;
645 raw_spin_unlock(&rt_rq->rt_runtime_lock);
646
647 /*
648 * Calculate the difference between what we started out with
649 * and what we current have, that's the amount of runtime
650 * we lend and now have to reclaim.
651 */
652 want = rt_b->rt_runtime - rt_rq->rt_runtime;
653
654 /*
655 * Greedy reclaim, take back as much as we can.
656 */
657 for_each_cpu(i, rd->span) {
658 struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
659 s64 diff;
660
661 /*
662 * Can't reclaim from ourselves or disabled runqueues.
663 */
664 if (iter == rt_rq || iter->rt_runtime == RUNTIME_INF)
665 continue;
666
667 raw_spin_lock(&iter->rt_runtime_lock);
668 if (want > 0) {
669 diff = min_t(s64, iter->rt_runtime, want);
670 iter->rt_runtime -= diff;
671 want -= diff;
672 } else {
673 iter->rt_runtime -= want;
674 want -= want;
675 }
676 raw_spin_unlock(&iter->rt_runtime_lock);
677
678 if (!want)
679 break;
680 }
681
682 raw_spin_lock(&rt_rq->rt_runtime_lock);
683 /*
684 * We cannot be left wanting - that would mean some runtime
685 * leaked out of the system.
686 */
687 BUG_ON(want);
688balanced:
689 /*
690 * Disable all the borrow logic by pretending we have inf
691 * runtime - in which case borrowing doesn't make sense.
692 */
693 rt_rq->rt_runtime = RUNTIME_INF;
694 raw_spin_unlock(&rt_rq->rt_runtime_lock);
695 raw_spin_unlock(&rt_b->rt_runtime_lock);
696 }
697}
698
699static void disable_runtime(struct rq *rq)
700{
701 unsigned long flags;
702
703 raw_spin_lock_irqsave(&rq->lock, flags);
704 __disable_runtime(rq);
705 raw_spin_unlock_irqrestore(&rq->lock, flags);
706}
707
708static void __enable_runtime(struct rq *rq)
709{
710 rt_rq_iter_t iter;
711 struct rt_rq *rt_rq;
712
713 if (unlikely(!scheduler_running))
714 return;
715
716 /*
717 * Reset each runqueue's bandwidth settings
718 */
719 for_each_rt_rq(rt_rq, iter, rq) {
720 struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
721
722 raw_spin_lock(&rt_b->rt_runtime_lock);
723 raw_spin_lock(&rt_rq->rt_runtime_lock);
724 rt_rq->rt_runtime = rt_b->rt_runtime;
725 rt_rq->rt_time = 0;
726 rt_rq->rt_throttled = 0;
727 raw_spin_unlock(&rt_rq->rt_runtime_lock);
728 raw_spin_unlock(&rt_b->rt_runtime_lock);
729 }
730}
731
732static void enable_runtime(struct rq *rq)
733{
734 unsigned long flags;
735
736 raw_spin_lock_irqsave(&rq->lock, flags);
737 __enable_runtime(rq);
738 raw_spin_unlock_irqrestore(&rq->lock, flags);
739}
740
741int update_runtime(struct notifier_block *nfb, unsigned long action, void *hcpu)
742{
743 int cpu = (int)(long)hcpu;
744
745 switch (action) {
746 case CPU_DOWN_PREPARE:
747 case CPU_DOWN_PREPARE_FROZEN:
748 disable_runtime(cpu_rq(cpu));
749 return NOTIFY_OK;
750
751 case CPU_DOWN_FAILED:
752 case CPU_DOWN_FAILED_FROZEN:
753 case CPU_ONLINE:
754 case CPU_ONLINE_FROZEN:
755 enable_runtime(cpu_rq(cpu));
756 return NOTIFY_OK;
757
758 default:
759 return NOTIFY_DONE;
760 }
761}
762
763static int balance_runtime(struct rt_rq *rt_rq)
764{
765 int more = 0;
766
767 if (!sched_feat(RT_RUNTIME_SHARE))
768 return more;
769
770 if (rt_rq->rt_time > rt_rq->rt_runtime) {
771 raw_spin_unlock(&rt_rq->rt_runtime_lock);
772 more = do_balance_runtime(rt_rq);
773 raw_spin_lock(&rt_rq->rt_runtime_lock);
774 }
775
776 return more;
777}
778#else /* !CONFIG_SMP */
779static inline int balance_runtime(struct rt_rq *rt_rq)
780{
781 return 0;
782}
783#endif /* CONFIG_SMP */
784
785static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
786{
787 int i, idle = 1, throttled = 0;
788 const struct cpumask *span;
789
790 span = sched_rt_period_mask();
791 for_each_cpu(i, span) {
792 int enqueue = 0;
793 struct rt_rq *rt_rq = sched_rt_period_rt_rq(rt_b, i);
794 struct rq *rq = rq_of_rt_rq(rt_rq);
795
796 raw_spin_lock(&rq->lock);
797 if (rt_rq->rt_time) {
798 u64 runtime;
799
800 raw_spin_lock(&rt_rq->rt_runtime_lock);
801 if (rt_rq->rt_throttled)
802 balance_runtime(rt_rq);
803 runtime = rt_rq->rt_runtime;
804 rt_rq->rt_time -= min(rt_rq->rt_time, overrun*runtime);
805 if (rt_rq->rt_throttled && rt_rq->rt_time < runtime) {
806 rt_rq->rt_throttled = 0;
807 enqueue = 1;
808
809 /*
810 * Force a clock update if the CPU was idle,
811 * lest wakeup -> unthrottle time accumulate.
812 */
813 if (rt_rq->rt_nr_running && rq->curr == rq->idle)
814 rq->skip_clock_update = -1;
815 }
816 if (rt_rq->rt_time || rt_rq->rt_nr_running)
817 idle = 0;
818 raw_spin_unlock(&rt_rq->rt_runtime_lock);
819 } else if (rt_rq->rt_nr_running) {
820 idle = 0;
821 if (!rt_rq_throttled(rt_rq))
822 enqueue = 1;
823 }
824 if (rt_rq->rt_throttled)
825 throttled = 1;
826
827 if (enqueue)
828 sched_rt_rq_enqueue(rt_rq);
829 raw_spin_unlock(&rq->lock);
830 }
831
832 if (!throttled && (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF))
833 return 1;
834
835 return idle;
836}
837
838static inline int rt_se_prio(struct sched_rt_entity *rt_se)
839{
840#ifdef CONFIG_RT_GROUP_SCHED
841 struct rt_rq *rt_rq = group_rt_rq(rt_se);
842
843 if (rt_rq)
844 return rt_rq->highest_prio.curr;
845#endif
846
847 return rt_task_of(rt_se)->prio;
848}
849
850static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq)
851{
852 u64 runtime = sched_rt_runtime(rt_rq);
853
854 if (rt_rq->rt_throttled)
855 return rt_rq_throttled(rt_rq);
856
857 if (runtime >= sched_rt_period(rt_rq))
858 return 0;
859
860 balance_runtime(rt_rq);
861 runtime = sched_rt_runtime(rt_rq);
862 if (runtime == RUNTIME_INF)
863 return 0;
864
865 if (rt_rq->rt_time > runtime) {
866 struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
867
868 /*
869 * Don't actually throttle groups that have no runtime assigned
870 * but accrue some time due to boosting.
871 */
872 if (likely(rt_b->rt_runtime)) {
873 static bool once = false;
874
875 rt_rq->rt_throttled = 1;
876
877 if (!once) {
878 once = true;
879 printk_sched("sched: RT throttling activated\n");
880 }
881 } else {
882 /*
883 * In case we did anyway, make it go away,
884 * replenishment is a joke, since it will replenish us
885 * with exactly 0 ns.
886 */
887 rt_rq->rt_time = 0;
888 }
889
890 if (rt_rq_throttled(rt_rq)) {
891 sched_rt_rq_dequeue(rt_rq);
892 return 1;
893 }
894 }
895
896 return 0;
897}
898
899/*
900 * Update the current task's runtime statistics. Skip current tasks that
901 * are not in our scheduling class.
902 */
903static void update_curr_rt(struct rq *rq)
904{
905 struct task_struct *curr = rq->curr;
906 struct sched_rt_entity *rt_se = &curr->rt;
907 struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
908 u64 delta_exec;
909
910 if (curr->sched_class != &rt_sched_class)
911 return;
912
913 delta_exec = rq->clock_task - curr->se.exec_start;
914 if (unlikely((s64)delta_exec < 0))
915 delta_exec = 0;
916
917 schedstat_set(curr->se.statistics.exec_max,
918 max(curr->se.statistics.exec_max, delta_exec));
919
920 curr->se.sum_exec_runtime += delta_exec;
921 account_group_exec_runtime(curr, delta_exec);
922
923 curr->se.exec_start = rq->clock_task;
924 cpuacct_charge(curr, delta_exec);
925
926 sched_rt_avg_update(rq, delta_exec);
927
928 if (!rt_bandwidth_enabled())
929 return;
930
931 for_each_sched_rt_entity(rt_se) {
932 rt_rq = rt_rq_of_se(rt_se);
933
934 if (sched_rt_runtime(rt_rq) != RUNTIME_INF) {
935 raw_spin_lock(&rt_rq->rt_runtime_lock);
936 rt_rq->rt_time += delta_exec;
937 if (sched_rt_runtime_exceeded(rt_rq))
938 resched_task(curr);
939 raw_spin_unlock(&rt_rq->rt_runtime_lock);
940 }
941 }
942}
943
944#if defined CONFIG_SMP
945
946static void
947inc_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio)
948{
949 struct rq *rq = rq_of_rt_rq(rt_rq);
950
951 if (rq->online && prio < prev_prio)
952 cpupri_set(&rq->rd->cpupri, rq->cpu, prio);
953}
954
955static void
956dec_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio)
957{
958 struct rq *rq = rq_of_rt_rq(rt_rq);
959
960 if (rq->online && rt_rq->highest_prio.curr != prev_prio)
961 cpupri_set(&rq->rd->cpupri, rq->cpu, rt_rq->highest_prio.curr);
962}
963
964#else /* CONFIG_SMP */
965
966static inline
967void inc_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio) {}
968static inline
969void dec_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio) {}
970
971#endif /* CONFIG_SMP */
972
973#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
974static void
975inc_rt_prio(struct rt_rq *rt_rq, int prio)
976{
977 int prev_prio = rt_rq->highest_prio.curr;
978
979 if (prio < prev_prio)
980 rt_rq->highest_prio.curr = prio;
981
982 inc_rt_prio_smp(rt_rq, prio, prev_prio);
983}
984
985static void
986dec_rt_prio(struct rt_rq *rt_rq, int prio)
987{
988 int prev_prio = rt_rq->highest_prio.curr;
989
990 if (rt_rq->rt_nr_running) {
991
992 WARN_ON(prio < prev_prio);
993
994 /*
995 * This may have been our highest task, and therefore
996 * we may have some recomputation to do
997 */
998 if (prio == prev_prio) {
999 struct rt_prio_array *array = &rt_rq->active;
1000
1001 rt_rq->highest_prio.curr =
1002 sched_find_first_bit(array->bitmap);
1003 }
1004
1005 } else
1006 rt_rq->highest_prio.curr = MAX_RT_PRIO;
1007
1008 dec_rt_prio_smp(rt_rq, prio, prev_prio);
1009}
1010
1011#else
1012
1013static inline void inc_rt_prio(struct rt_rq *rt_rq, int prio) {}
1014static inline void dec_rt_prio(struct rt_rq *rt_rq, int prio) {}
1015
1016#endif /* CONFIG_SMP || CONFIG_RT_GROUP_SCHED */
1017
1018#ifdef CONFIG_RT_GROUP_SCHED
1019
1020static void
1021inc_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
1022{
1023 if (rt_se_boosted(rt_se))
1024 rt_rq->rt_nr_boosted++;
1025
1026 if (rt_rq->tg)
1027 start_rt_bandwidth(&rt_rq->tg->rt_bandwidth);
1028}
1029
1030static void
1031dec_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
1032{
1033 if (rt_se_boosted(rt_se))
1034 rt_rq->rt_nr_boosted--;
1035
1036 WARN_ON(!rt_rq->rt_nr_running && rt_rq->rt_nr_boosted);
1037}
1038
1039#else /* CONFIG_RT_GROUP_SCHED */
1040
1041static void
1042inc_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
1043{
1044 start_rt_bandwidth(&def_rt_bandwidth);
1045}
1046
1047static inline
1048void dec_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) {}
1049
1050#endif /* CONFIG_RT_GROUP_SCHED */
1051
1052static inline
1053void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
1054{
1055 int prio = rt_se_prio(rt_se);
1056
1057 WARN_ON(!rt_prio(prio));
1058 rt_rq->rt_nr_running++;
1059
1060 inc_rt_prio(rt_rq, prio);
1061 inc_rt_migration(rt_se, rt_rq);
1062 inc_rt_group(rt_se, rt_rq);
1063}
1064
1065static inline
1066void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
1067{
1068 WARN_ON(!rt_prio(rt_se_prio(rt_se)));
1069 WARN_ON(!rt_rq->rt_nr_running);
1070 rt_rq->rt_nr_running--;
1071
1072 dec_rt_prio(rt_rq, rt_se_prio(rt_se));
1073 dec_rt_migration(rt_se, rt_rq);
1074 dec_rt_group(rt_se, rt_rq);
1075}
1076
1077static void __enqueue_rt_entity(struct sched_rt_entity *rt_se, bool head)
1078{
1079 struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
1080 struct rt_prio_array *array = &rt_rq->active;
1081 struct rt_rq *group_rq = group_rt_rq(rt_se);
1082 struct list_head *queue = array->queue + rt_se_prio(rt_se);
1083
1084 /*
1085 * Don't enqueue the group if its throttled, or when empty.
1086 * The latter is a consequence of the former when a child group
1087 * get throttled and the current group doesn't have any other
1088 * active members.
1089 */
1090 if (group_rq && (rt_rq_throttled(group_rq) || !group_rq->rt_nr_running))
1091 return;
1092
1093 if (!rt_rq->rt_nr_running)
1094 list_add_leaf_rt_rq(rt_rq);
1095
1096 if (head)
1097 list_add(&rt_se->run_list, queue);
1098 else
1099 list_add_tail(&rt_se->run_list, queue);
1100 __set_bit(rt_se_prio(rt_se), array->bitmap);
1101
1102 inc_rt_tasks(rt_se, rt_rq);
1103}
1104
1105static void __dequeue_rt_entity(struct sched_rt_entity *rt_se)
1106{
1107 struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
1108 struct rt_prio_array *array = &rt_rq->active;
1109
1110 list_del_init(&rt_se->run_list);
1111 if (list_empty(array->queue + rt_se_prio(rt_se)))
1112 __clear_bit(rt_se_prio(rt_se), array->bitmap);
1113
1114 dec_rt_tasks(rt_se, rt_rq);
1115 if (!rt_rq->rt_nr_running)
1116 list_del_leaf_rt_rq(rt_rq);
1117}
1118
1119/*
1120 * Because the prio of an upper entry depends on the lower
1121 * entries, we must remove entries top - down.
1122 */
1123static void dequeue_rt_stack(struct sched_rt_entity *rt_se)
1124{
1125 struct sched_rt_entity *back = NULL;
1126
1127 for_each_sched_rt_entity(rt_se) {
1128 rt_se->back = back;
1129 back = rt_se;
1130 }
1131
1132 for (rt_se = back; rt_se; rt_se = rt_se->back) {
1133 if (on_rt_rq(rt_se))
1134 __dequeue_rt_entity(rt_se);
1135 }
1136}
1137
1138static void enqueue_rt_entity(struct sched_rt_entity *rt_se, bool head)
1139{
1140 dequeue_rt_stack(rt_se);
1141 for_each_sched_rt_entity(rt_se)
1142 __enqueue_rt_entity(rt_se, head);
1143}
1144
1145static void dequeue_rt_entity(struct sched_rt_entity *rt_se)
1146{
1147 dequeue_rt_stack(rt_se);
1148
1149 for_each_sched_rt_entity(rt_se) {
1150 struct rt_rq *rt_rq = group_rt_rq(rt_se);
1151
1152 if (rt_rq && rt_rq->rt_nr_running)
1153 __enqueue_rt_entity(rt_se, false);
1154 }
1155}
1156
1157/*
1158 * Adding/removing a task to/from a priority array:
1159 */
1160static void
1161enqueue_task_rt(struct rq *rq, struct task_struct *p, int flags)
1162{
1163 struct sched_rt_entity *rt_se = &p->rt;
1164
1165 if (flags & ENQUEUE_WAKEUP)
1166 rt_se->timeout = 0;
1167
1168 enqueue_rt_entity(rt_se, flags & ENQUEUE_HEAD);
1169
1170 if (!task_current(rq, p) && p->nr_cpus_allowed > 1)
1171 enqueue_pushable_task(rq, p);
1172
1173 inc_nr_running(rq);
1174}
1175
1176static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int flags)
1177{
1178 struct sched_rt_entity *rt_se = &p->rt;
1179
1180 update_curr_rt(rq);
1181 dequeue_rt_entity(rt_se);
1182
1183 dequeue_pushable_task(rq, p);
1184
1185 dec_nr_running(rq);
1186}
1187
1188/*
1189 * Put task to the head or the end of the run list without the overhead of
1190 * dequeue followed by enqueue.
1191 */
1192static void
1193requeue_rt_entity(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se, int head)
1194{
1195 if (on_rt_rq(rt_se)) {
1196 struct rt_prio_array *array = &rt_rq->active;
1197 struct list_head *queue = array->queue + rt_se_prio(rt_se);
1198
1199 if (head)
1200 list_move(&rt_se->run_list, queue);
1201 else
1202 list_move_tail(&rt_se->run_list, queue);
1203 }
1204}
1205
1206static void requeue_task_rt(struct rq *rq, struct task_struct *p, int head)
1207{
1208 struct sched_rt_entity *rt_se = &p->rt;
1209 struct rt_rq *rt_rq;
1210
1211 for_each_sched_rt_entity(rt_se) {
1212 rt_rq = rt_rq_of_se(rt_se);
1213 requeue_rt_entity(rt_rq, rt_se, head);
1214 }
1215}
1216
1217static void yield_task_rt(struct rq *rq)
1218{
1219 requeue_task_rt(rq, rq->curr, 0);
1220}
1221
1222#ifdef CONFIG_SMP
1223static int find_lowest_rq(struct task_struct *task);
1224
1225static int
1226select_task_rq_rt(struct task_struct *p, int sd_flag, int flags)
1227{
1228 struct task_struct *curr;
1229 struct rq *rq;
1230 int cpu;
1231
1232 cpu = task_cpu(p);
1233
1234 if (p->nr_cpus_allowed == 1)
1235 goto out;
1236
1237 /* For anything but wake ups, just return the task_cpu */
1238 if (sd_flag != SD_BALANCE_WAKE && sd_flag != SD_BALANCE_FORK)
1239 goto out;
1240
1241 rq = cpu_rq(cpu);
1242
1243 rcu_read_lock();
1244 curr = ACCESS_ONCE(rq->curr); /* unlocked access */
1245
1246 /*
1247 * If the current task on @p's runqueue is an RT task, then
1248 * try to see if we can wake this RT task up on another
1249 * runqueue. Otherwise simply start this RT task
1250 * on its current runqueue.
1251 *
1252 * We want to avoid overloading runqueues. If the woken
1253 * task is a higher priority, then it will stay on this CPU
1254 * and the lower prio task should be moved to another CPU.
1255 * Even though this will probably make the lower prio task
1256 * lose its cache, we do not want to bounce a higher task
1257 * around just because it gave up its CPU, perhaps for a
1258 * lock?
1259 *
1260 * For equal prio tasks, we just let the scheduler sort it out.
1261 *
1262 * Otherwise, just let it ride on the affined RQ and the
1263 * post-schedule router will push the preempted task away
1264 *
1265 * This test is optimistic, if we get it wrong the load-balancer
1266 * will have to sort it out.
1267 */
1268 if (curr && unlikely(rt_task(curr)) &&
1269 (curr->nr_cpus_allowed < 2 ||
1270 curr->prio <= p->prio) &&
1271 (p->nr_cpus_allowed > 1)) {
1272 int target = find_lowest_rq(p);
1273
1274 if (target != -1)
1275 cpu = target;
1276 }
1277 rcu_read_unlock();
1278
1279out:
1280 return cpu;
1281}
1282
1283static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p)
1284{
1285 if (rq->curr->nr_cpus_allowed == 1)
1286 return;
1287
1288 if (p->nr_cpus_allowed != 1
1289 && cpupri_find(&rq->rd->cpupri, p, NULL))
1290 return;
1291
1292 if (!cpupri_find(&rq->rd->cpupri, rq->curr, NULL))
1293 return;
1294
1295 /*
1296 * There appears to be other cpus that can accept
1297 * current and none to run 'p', so lets reschedule
1298 * to try and push current away:
1299 */
1300 requeue_task_rt(rq, p, 1);
1301 resched_task(rq->curr);
1302}
1303
1304#endif /* CONFIG_SMP */
1305
1306/*
1307 * Preempt the current task with a newly woken task if needed:
1308 */
1309static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p, int flags)
1310{
1311 if (p->prio < rq->curr->prio) {
1312 resched_task(rq->curr);
1313 return;
1314 }
1315
1316#ifdef CONFIG_SMP
1317 /*
1318 * If:
1319 *
1320 * - the newly woken task is of equal priority to the current task
1321 * - the newly woken task is non-migratable while current is migratable
1322 * - current will be preempted on the next reschedule
1323 *
1324 * we should check to see if current can readily move to a different
1325 * cpu. If so, we will reschedule to allow the push logic to try
1326 * to move current somewhere else, making room for our non-migratable
1327 * task.
1328 */
1329 if (p->prio == rq->curr->prio && !test_tsk_need_resched(rq->curr))
1330 check_preempt_equal_prio(rq, p);
1331#endif
1332}
1333
1334static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq,
1335 struct rt_rq *rt_rq)
1336{
1337 struct rt_prio_array *array = &rt_rq->active;
1338 struct sched_rt_entity *next = NULL;
1339 struct list_head *queue;
1340 int idx;
1341
1342 idx = sched_find_first_bit(array->bitmap);
1343 BUG_ON(idx >= MAX_RT_PRIO);
1344
1345 queue = array->queue + idx;
1346 next = list_entry(queue->next, struct sched_rt_entity, run_list);
1347
1348 return next;
1349}
1350
1351static struct task_struct *_pick_next_task_rt(struct rq *rq)
1352{
1353 struct sched_rt_entity *rt_se;
1354 struct task_struct *p;
1355 struct rt_rq *rt_rq;
1356
1357 rt_rq = &rq->rt;
1358
1359 if (!rt_rq->rt_nr_running)
1360 return NULL;
1361
1362 if (rt_rq_throttled(rt_rq))
1363 return NULL;
1364
1365 do {
1366 rt_se = pick_next_rt_entity(rq, rt_rq);
1367 BUG_ON(!rt_se);
1368 rt_rq = group_rt_rq(rt_se);
1369 } while (rt_rq);
1370
1371 p = rt_task_of(rt_se);
1372 p->se.exec_start = rq->clock_task;
1373
1374 return p;
1375}
1376
1377static struct task_struct *pick_next_task_rt(struct rq *rq)
1378{
1379 struct task_struct *p = _pick_next_task_rt(rq);
1380
1381 /* The running task is never eligible for pushing */
1382 if (p)
1383 dequeue_pushable_task(rq, p);
1384
1385#ifdef CONFIG_SMP
1386 /*
1387 * We detect this state here so that we can avoid taking the RQ
1388 * lock again later if there is no need to push
1389 */
1390 rq->post_schedule = has_pushable_tasks(rq);
1391#endif
1392
1393 return p;
1394}
1395
1396static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
1397{
1398 update_curr_rt(rq);
1399
1400 /*
1401 * The previous task needs to be made eligible for pushing
1402 * if it is still active
1403 */
1404 if (on_rt_rq(&p->rt) && p->nr_cpus_allowed > 1)
1405 enqueue_pushable_task(rq, p);
1406}
1407
1408#ifdef CONFIG_SMP
1409
1410/* Only try algorithms three times */
1411#define RT_MAX_TRIES 3
1412
1413static int pick_rt_task(struct rq *rq, struct task_struct *p, int cpu)
1414{
1415 if (!task_running(rq, p) &&
1416 (cpu < 0 || cpumask_test_cpu(cpu, tsk_cpus_allowed(p))) &&
1417 (p->nr_cpus_allowed > 1))
1418 return 1;
1419 return 0;
1420}
1421
1422/* Return the second highest RT task, NULL otherwise */
1423static struct task_struct *pick_next_highest_task_rt(struct rq *rq, int cpu)
1424{
1425 struct task_struct *next = NULL;
1426 struct sched_rt_entity *rt_se;
1427 struct rt_prio_array *array;
1428 struct rt_rq *rt_rq;
1429 int idx;
1430
1431 for_each_leaf_rt_rq(rt_rq, rq) {
1432 array = &rt_rq->active;
1433 idx = sched_find_first_bit(array->bitmap);
1434next_idx:
1435 if (idx >= MAX_RT_PRIO)
1436 continue;
1437 if (next && next->prio <= idx)
1438 continue;
1439 list_for_each_entry(rt_se, array->queue + idx, run_list) {
1440 struct task_struct *p;
1441
1442 if (!rt_entity_is_task(rt_se))
1443 continue;
1444
1445 p = rt_task_of(rt_se);
1446 if (pick_rt_task(rq, p, cpu)) {
1447 next = p;
1448 break;
1449 }
1450 }
1451 if (!next) {
1452 idx = find_next_bit(array->bitmap, MAX_RT_PRIO, idx+1);
1453 goto next_idx;
1454 }
1455 }
1456
1457 return next;
1458}
1459
1460static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask);
1461
1462static int find_lowest_rq(struct task_struct *task)
1463{
1464 struct sched_domain *sd;
1465 struct cpumask *lowest_mask = __get_cpu_var(local_cpu_mask);
1466 int this_cpu = smp_processor_id();
1467 int cpu = task_cpu(task);
1468
1469 /* Make sure the mask is initialized first */
1470 if (unlikely(!lowest_mask))
1471 return -1;
1472
1473 if (task->nr_cpus_allowed == 1)
1474 return -1; /* No other targets possible */
1475
1476 if (!cpupri_find(&task_rq(task)->rd->cpupri, task, lowest_mask))
1477 return -1; /* No targets found */
1478
1479 /*
1480 * At this point we have built a mask of cpus representing the
1481 * lowest priority tasks in the system. Now we want to elect
1482 * the best one based on our affinity and topology.
1483 *
1484 * We prioritize the last cpu that the task executed on since
1485 * it is most likely cache-hot in that location.
1486 */
1487 if (cpumask_test_cpu(cpu, lowest_mask))
1488 return cpu;
1489
1490 /*
1491 * Otherwise, we consult the sched_domains span maps to figure
1492 * out which cpu is logically closest to our hot cache data.
1493 */
1494 if (!cpumask_test_cpu(this_cpu, lowest_mask))
1495 this_cpu = -1; /* Skip this_cpu opt if not among lowest */
1496
1497 rcu_read_lock();
1498 for_each_domain(cpu, sd) {
1499 if (sd->flags & SD_WAKE_AFFINE) {
1500 int best_cpu;
1501
1502 /*
1503 * "this_cpu" is cheaper to preempt than a
1504 * remote processor.
1505 */
1506 if (this_cpu != -1 &&
1507 cpumask_test_cpu(this_cpu, sched_domain_span(sd))) {
1508 rcu_read_unlock();
1509 return this_cpu;
1510 }
1511
1512 best_cpu = cpumask_first_and(lowest_mask,
1513 sched_domain_span(sd));
1514 if (best_cpu < nr_cpu_ids) {
1515 rcu_read_unlock();
1516 return best_cpu;
1517 }
1518 }
1519 }
1520 rcu_read_unlock();
1521
1522 /*
1523 * And finally, if there were no matches within the domains
1524 * just give the caller *something* to work with from the compatible
1525 * locations.
1526 */
1527 if (this_cpu != -1)
1528 return this_cpu;
1529
1530 cpu = cpumask_any(lowest_mask);
1531 if (cpu < nr_cpu_ids)
1532 return cpu;
1533 return -1;
1534}
1535
1536/* Will lock the rq it finds */
1537static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq)
1538{
1539 struct rq *lowest_rq = NULL;
1540 int tries;
1541 int cpu;
1542
1543 for (tries = 0; tries < RT_MAX_TRIES; tries++) {
1544 cpu = find_lowest_rq(task);
1545
1546 if ((cpu == -1) || (cpu == rq->cpu))
1547 break;
1548
1549 lowest_rq = cpu_rq(cpu);
1550
1551 /* if the prio of this runqueue changed, try again */
1552 if (double_lock_balance(rq, lowest_rq)) {
1553 /*
1554 * We had to unlock the run queue. In
1555 * the mean time, task could have
1556 * migrated already or had its affinity changed.
1557 * Also make sure that it wasn't scheduled on its rq.
1558 */
1559 if (unlikely(task_rq(task) != rq ||
1560 !cpumask_test_cpu(lowest_rq->cpu,
1561 tsk_cpus_allowed(task)) ||
1562 task_running(rq, task) ||
1563 !task->on_rq)) {
1564
1565 double_unlock_balance(rq, lowest_rq);
1566 lowest_rq = NULL;
1567 break;
1568 }
1569 }
1570
1571 /* If this rq is still suitable use it. */
1572 if (lowest_rq->rt.highest_prio.curr > task->prio)
1573 break;
1574
1575 /* try again */
1576 double_unlock_balance(rq, lowest_rq);
1577 lowest_rq = NULL;
1578 }
1579
1580 return lowest_rq;
1581}
1582
1583static struct task_struct *pick_next_pushable_task(struct rq *rq)
1584{
1585 struct task_struct *p;
1586
1587 if (!has_pushable_tasks(rq))
1588 return NULL;
1589
1590 p = plist_first_entry(&rq->rt.pushable_tasks,
1591 struct task_struct, pushable_tasks);
1592
1593 BUG_ON(rq->cpu != task_cpu(p));
1594 BUG_ON(task_current(rq, p));
1595 BUG_ON(p->nr_cpus_allowed <= 1);
1596
1597 BUG_ON(!p->on_rq);
1598 BUG_ON(!rt_task(p));
1599
1600 return p;
1601}
1602
1603/*
1604 * If the current CPU has more than one RT task, see if the non
1605 * running task can migrate over to a CPU that is running a task
1606 * of lesser priority.
1607 */
1608static int push_rt_task(struct rq *rq)
1609{
1610 struct task_struct *next_task;
1611 struct rq *lowest_rq;
1612 int ret = 0;
1613
1614 if (!rq->rt.overloaded)
1615 return 0;
1616
1617 next_task = pick_next_pushable_task(rq);
1618 if (!next_task)
1619 return 0;
1620
1621#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
1622 if (unlikely(task_running(rq, next_task)))
1623 return 0;
1624#endif
1625
1626retry:
1627 if (unlikely(next_task == rq->curr)) {
1628 WARN_ON(1);
1629 return 0;
1630 }
1631
1632 /*
1633 * It's possible that the next_task slipped in of
1634 * higher priority than current. If that's the case
1635 * just reschedule current.
1636 */
1637 if (unlikely(next_task->prio < rq->curr->prio)) {
1638 resched_task(rq->curr);
1639 return 0;
1640 }
1641
1642 /* We might release rq lock */
1643 get_task_struct(next_task);
1644
1645 /* find_lock_lowest_rq locks the rq if found */
1646 lowest_rq = find_lock_lowest_rq(next_task, rq);
1647 if (!lowest_rq) {
1648 struct task_struct *task;
1649 /*
1650 * find_lock_lowest_rq releases rq->lock
1651 * so it is possible that next_task has migrated.
1652 *
1653 * We need to make sure that the task is still on the same
1654 * run-queue and is also still the next task eligible for
1655 * pushing.
1656 */
1657 task = pick_next_pushable_task(rq);
1658 if (task_cpu(next_task) == rq->cpu && task == next_task) {
1659 /*
1660 * The task hasn't migrated, and is still the next
1661 * eligible task, but we failed to find a run-queue
1662 * to push it to. Do not retry in this case, since
1663 * other cpus will pull from us when ready.
1664 */
1665 goto out;
1666 }
1667
1668 if (!task)
1669 /* No more tasks, just exit */
1670 goto out;
1671
1672 /*
1673 * Something has shifted, try again.
1674 */
1675 put_task_struct(next_task);
1676 next_task = task;
1677 goto retry;
1678 }
1679
1680 deactivate_task(rq, next_task, 0);
1681 set_task_cpu(next_task, lowest_rq->cpu);
1682 activate_task(lowest_rq, next_task, 0);
1683 ret = 1;
1684
1685 resched_task(lowest_rq->curr);
1686
1687 double_unlock_balance(rq, lowest_rq);
1688
1689out:
1690 put_task_struct(next_task);
1691
1692 return ret;
1693}
1694
1695static void push_rt_tasks(struct rq *rq)
1696{
1697 /* push_rt_task will return true if it moved an RT */
1698 while (push_rt_task(rq))
1699 ;
1700}
1701
1702static int pull_rt_task(struct rq *this_rq)
1703{
1704 int this_cpu = this_rq->cpu, ret = 0, cpu;
1705 struct task_struct *p;
1706 struct rq *src_rq;
1707
1708 if (likely(!rt_overloaded(this_rq)))
1709 return 0;
1710
1711 for_each_cpu(cpu, this_rq->rd->rto_mask) {
1712 if (this_cpu == cpu)
1713 continue;
1714
1715 src_rq = cpu_rq(cpu);
1716
1717 /*
1718 * Don't bother taking the src_rq->lock if the next highest
1719 * task is known to be lower-priority than our current task.
1720 * This may look racy, but if this value is about to go
1721 * logically higher, the src_rq will push this task away.
1722 * And if its going logically lower, we do not care
1723 */
1724 if (src_rq->rt.highest_prio.next >=
1725 this_rq->rt.highest_prio.curr)
1726 continue;
1727
1728 /*
1729 * We can potentially drop this_rq's lock in
1730 * double_lock_balance, and another CPU could
1731 * alter this_rq
1732 */
1733 double_lock_balance(this_rq, src_rq);
1734
1735 /*
1736 * Are there still pullable RT tasks?
1737 */
1738 if (src_rq->rt.rt_nr_running <= 1)
1739 goto skip;
1740
1741 p = pick_next_highest_task_rt(src_rq, this_cpu);
1742
1743 /*
1744 * Do we have an RT task that preempts
1745 * the to-be-scheduled task?
1746 */
1747 if (p && (p->prio < this_rq->rt.highest_prio.curr)) {
1748 WARN_ON(p == src_rq->curr);
1749 WARN_ON(!p->on_rq);
1750
1751 /*
1752 * There's a chance that p is higher in priority
1753 * than what's currently running on its cpu.
1754 * This is just that p is wakeing up and hasn't
1755 * had a chance to schedule. We only pull
1756 * p if it is lower in priority than the
1757 * current task on the run queue
1758 */
1759 if (p->prio < src_rq->curr->prio)
1760 goto skip;
1761
1762 ret = 1;
1763
1764 deactivate_task(src_rq, p, 0);
1765 set_task_cpu(p, this_cpu);
1766 activate_task(this_rq, p, 0);
1767 /*
1768 * We continue with the search, just in
1769 * case there's an even higher prio task
1770 * in another runqueue. (low likelihood
1771 * but possible)
1772 */
1773 }
1774skip:
1775 double_unlock_balance(this_rq, src_rq);
1776 }
1777
1778 return ret;
1779}
1780
1781static void pre_schedule_rt(struct rq *rq, struct task_struct *prev)
1782{
1783 /* Try to pull RT tasks here if we lower this rq's prio */
1784 if (rq->rt.highest_prio.curr > prev->prio)
1785 pull_rt_task(rq);
1786}
1787
1788static void post_schedule_rt(struct rq *rq)
1789{
1790 push_rt_tasks(rq);
1791}
1792
1793/*
1794 * If we are not running and we are not going to reschedule soon, we should
1795 * try to push tasks away now
1796 */
1797static void task_woken_rt(struct rq *rq, struct task_struct *p)
1798{
1799 if (!task_running(rq, p) &&
1800 !test_tsk_need_resched(rq->curr) &&
1801 has_pushable_tasks(rq) &&
1802 p->nr_cpus_allowed > 1 &&
1803 rt_task(rq->curr) &&
1804 (rq->curr->nr_cpus_allowed < 2 ||
1805 rq->curr->prio <= p->prio))
1806 push_rt_tasks(rq);
1807}
1808
1809static void set_cpus_allowed_rt(struct task_struct *p,
1810 const struct cpumask *new_mask)
1811{
1812 struct rq *rq;
1813 int weight;
1814
1815 BUG_ON(!rt_task(p));
1816
1817 if (!p->on_rq)
1818 return;
1819
1820 weight = cpumask_weight(new_mask);
1821
1822 /*
1823 * Only update if the process changes its state from whether it
1824 * can migrate or not.
1825 */
1826 if ((p->nr_cpus_allowed > 1) == (weight > 1))
1827 return;
1828
1829 rq = task_rq(p);
1830
1831 /*
1832 * The process used to be able to migrate OR it can now migrate
1833 */
1834 if (weight <= 1) {
1835 if (!task_current(rq, p))
1836 dequeue_pushable_task(rq, p);
1837 BUG_ON(!rq->rt.rt_nr_migratory);
1838 rq->rt.rt_nr_migratory--;
1839 } else {
1840 if (!task_current(rq, p))
1841 enqueue_pushable_task(rq, p);
1842 rq->rt.rt_nr_migratory++;
1843 }
1844
1845 update_rt_migration(&rq->rt);
1846}
1847
1848/* Assumes rq->lock is held */
1849static void rq_online_rt(struct rq *rq)
1850{
1851 if (rq->rt.overloaded)
1852 rt_set_overload(rq);
1853
1854 __enable_runtime(rq);
1855
1856 cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio.curr);
1857}
1858
1859/* Assumes rq->lock is held */
1860static void rq_offline_rt(struct rq *rq)
1861{
1862 if (rq->rt.overloaded)
1863 rt_clear_overload(rq);
1864
1865 __disable_runtime(rq);
1866
1867 cpupri_set(&rq->rd->cpupri, rq->cpu, CPUPRI_INVALID);
1868}
1869
1870/*
1871 * When switch from the rt queue, we bring ourselves to a position
1872 * that we might want to pull RT tasks from other runqueues.
1873 */
1874static void switched_from_rt(struct rq *rq, struct task_struct *p)
1875{
1876 /*
1877 * If there are other RT tasks then we will reschedule
1878 * and the scheduling of the other RT tasks will handle
1879 * the balancing. But if we are the last RT task
1880 * we may need to handle the pulling of RT tasks
1881 * now.
1882 */
1883 if (p->on_rq && !rq->rt.rt_nr_running)
1884 pull_rt_task(rq);
1885}
1886
1887void init_sched_rt_class(void)
1888{
1889 unsigned int i;
1890
1891 for_each_possible_cpu(i) {
1892 zalloc_cpumask_var_node(&per_cpu(local_cpu_mask, i),
1893 GFP_KERNEL, cpu_to_node(i));
1894 }
1895}
1896#endif /* CONFIG_SMP */
1897
1898/*
1899 * When switching a task to RT, we may overload the runqueue
1900 * with RT tasks. In this case we try to push them off to
1901 * other runqueues.
1902 */
1903static void switched_to_rt(struct rq *rq, struct task_struct *p)
1904{
1905 int check_resched = 1;
1906
1907 /*
1908 * If we are already running, then there's nothing
1909 * that needs to be done. But if we are not running
1910 * we may need to preempt the current running task.
1911 * If that current running task is also an RT task
1912 * then see if we can move to another run queue.
1913 */
1914 if (p->on_rq && rq->curr != p) {
1915#ifdef CONFIG_SMP
1916 if (rq->rt.overloaded && push_rt_task(rq) &&
1917 /* Don't resched if we changed runqueues */
1918 rq != task_rq(p))
1919 check_resched = 0;
1920#endif /* CONFIG_SMP */
1921 if (check_resched && p->prio < rq->curr->prio)
1922 resched_task(rq->curr);
1923 }
1924}
1925
1926/*
1927 * Priority of the task has changed. This may cause
1928 * us to initiate a push or pull.
1929 */
1930static void
1931prio_changed_rt(struct rq *rq, struct task_struct *p, int oldprio)
1932{
1933 if (!p->on_rq)
1934 return;
1935
1936 if (rq->curr == p) {
1937#ifdef CONFIG_SMP
1938 /*
1939 * If our priority decreases while running, we
1940 * may need to pull tasks to this runqueue.
1941 */
1942 if (oldprio < p->prio)
1943 pull_rt_task(rq);
1944 /*
1945 * If there's a higher priority task waiting to run
1946 * then reschedule. Note, the above pull_rt_task
1947 * can release the rq lock and p could migrate.
1948 * Only reschedule if p is still on the same runqueue.
1949 */
1950 if (p->prio > rq->rt.highest_prio.curr && rq->curr == p)
1951 resched_task(p);
1952#else
1953 /* For UP simply resched on drop of prio */
1954 if (oldprio < p->prio)
1955 resched_task(p);
1956#endif /* CONFIG_SMP */
1957 } else {
1958 /*
1959 * This task is not running, but if it is
1960 * greater than the current running task
1961 * then reschedule.
1962 */
1963 if (p->prio < rq->curr->prio)
1964 resched_task(rq->curr);
1965 }
1966}
1967
1968static void watchdog(struct rq *rq, struct task_struct *p)
1969{
1970 unsigned long soft, hard;
1971
1972 /* max may change after cur was read, this will be fixed next tick */
1973 soft = task_rlimit(p, RLIMIT_RTTIME);
1974 hard = task_rlimit_max(p, RLIMIT_RTTIME);
1975
1976 if (soft != RLIM_INFINITY) {
1977 unsigned long next;
1978
1979 p->rt.timeout++;
1980 next = DIV_ROUND_UP(min(soft, hard), USEC_PER_SEC/HZ);
1981 if (p->rt.timeout > next)
1982 p->cputime_expires.sched_exp = p->se.sum_exec_runtime;
1983 }
1984}
1985
1986static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued)
1987{
1988 struct sched_rt_entity *rt_se = &p->rt;
1989
1990 update_curr_rt(rq);
1991
1992 watchdog(rq, p);
1993
1994 /*
1995 * RR tasks need a special form of timeslice management.
1996 * FIFO tasks have no timeslices.
1997 */
1998 if (p->policy != SCHED_RR)
1999 return;
2000
2001 if (--p->rt.time_slice)
2002 return;
2003
2004 p->rt.time_slice = RR_TIMESLICE;
2005
2006 /*
2007 * Requeue to the end of queue if we (and all of our ancestors) are the
2008 * only element on the queue
2009 */
2010 for_each_sched_rt_entity(rt_se) {
2011 if (rt_se->run_list.prev != rt_se->run_list.next) {
2012 requeue_task_rt(rq, p, 0);
2013 set_tsk_need_resched(p);
2014 return;
2015 }
2016 }
2017}
2018
2019static void set_curr_task_rt(struct rq *rq)
2020{
2021 struct task_struct *p = rq->curr;
2022
2023 p->se.exec_start = rq->clock_task;
2024
2025 /* The running task is never eligible for pushing */
2026 dequeue_pushable_task(rq, p);
2027}
2028
2029static unsigned int get_rr_interval_rt(struct rq *rq, struct task_struct *task)
2030{
2031 /*
2032 * Time slice is 0 for SCHED_FIFO tasks
2033 */
2034 if (task->policy == SCHED_RR)
2035 return RR_TIMESLICE;
2036 else
2037 return 0;
2038}
2039
2040const struct sched_class rt_sched_class = {
2041 .next = &fair_sched_class,
2042 .enqueue_task = enqueue_task_rt,
2043 .dequeue_task = dequeue_task_rt,
2044 .yield_task = yield_task_rt,
2045
2046 .check_preempt_curr = check_preempt_curr_rt,
2047
2048 .pick_next_task = pick_next_task_rt,
2049 .put_prev_task = put_prev_task_rt,
2050
2051#ifdef CONFIG_SMP
2052 .select_task_rq = select_task_rq_rt,
2053
2054 .set_cpus_allowed = set_cpus_allowed_rt,
2055 .rq_online = rq_online_rt,
2056 .rq_offline = rq_offline_rt,
2057 .pre_schedule = pre_schedule_rt,
2058 .post_schedule = post_schedule_rt,
2059 .task_woken = task_woken_rt,
2060 .switched_from = switched_from_rt,
2061#endif
2062
2063 .set_curr_task = set_curr_task_rt,
2064 .task_tick = task_tick_rt,
2065
2066 .get_rr_interval = get_rr_interval_rt,
2067
2068 .prio_changed = prio_changed_rt,
2069 .switched_to = switched_to_rt,
2070};
2071
2072#ifdef CONFIG_SCHED_DEBUG
2073extern void print_rt_rq(struct seq_file *m, int cpu, struct rt_rq *rt_rq);
2074
2075void print_rt_stats(struct seq_file *m, int cpu)
2076{
2077 rt_rq_iter_t iter;
2078 struct rt_rq *rt_rq;
2079
2080 rcu_read_lock();
2081 for_each_rt_rq(rt_rq, iter, cpu_rq(cpu))
2082 print_rt_rq(m, cpu, rt_rq);
2083 rcu_read_unlock();
2084}
2085#endif /* CONFIG_SCHED_DEBUG */
1/*
2 * Real-Time Scheduling Class (mapped to the SCHED_FIFO and SCHED_RR
3 * policies)
4 */
5
6#include "sched.h"
7
8#include <linux/slab.h>
9#include <linux/irq_work.h>
10
11int sched_rr_timeslice = RR_TIMESLICE;
12
13static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun);
14
15struct rt_bandwidth def_rt_bandwidth;
16
17static enum hrtimer_restart sched_rt_period_timer(struct hrtimer *timer)
18{
19 struct rt_bandwidth *rt_b =
20 container_of(timer, struct rt_bandwidth, rt_period_timer);
21 int idle = 0;
22 int overrun;
23
24 raw_spin_lock(&rt_b->rt_runtime_lock);
25 for (;;) {
26 overrun = hrtimer_forward_now(timer, rt_b->rt_period);
27 if (!overrun)
28 break;
29
30 raw_spin_unlock(&rt_b->rt_runtime_lock);
31 idle = do_sched_rt_period_timer(rt_b, overrun);
32 raw_spin_lock(&rt_b->rt_runtime_lock);
33 }
34 if (idle)
35 rt_b->rt_period_active = 0;
36 raw_spin_unlock(&rt_b->rt_runtime_lock);
37
38 return idle ? HRTIMER_NORESTART : HRTIMER_RESTART;
39}
40
41void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime)
42{
43 rt_b->rt_period = ns_to_ktime(period);
44 rt_b->rt_runtime = runtime;
45
46 raw_spin_lock_init(&rt_b->rt_runtime_lock);
47
48 hrtimer_init(&rt_b->rt_period_timer,
49 CLOCK_MONOTONIC, HRTIMER_MODE_REL);
50 rt_b->rt_period_timer.function = sched_rt_period_timer;
51}
52
53static void start_rt_bandwidth(struct rt_bandwidth *rt_b)
54{
55 if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)
56 return;
57
58 raw_spin_lock(&rt_b->rt_runtime_lock);
59 if (!rt_b->rt_period_active) {
60 rt_b->rt_period_active = 1;
61 /*
62 * SCHED_DEADLINE updates the bandwidth, as a run away
63 * RT task with a DL task could hog a CPU. But DL does
64 * not reset the period. If a deadline task was running
65 * without an RT task running, it can cause RT tasks to
66 * throttle when they start up. Kick the timer right away
67 * to update the period.
68 */
69 hrtimer_forward_now(&rt_b->rt_period_timer, ns_to_ktime(0));
70 hrtimer_start_expires(&rt_b->rt_period_timer, HRTIMER_MODE_ABS_PINNED);
71 }
72 raw_spin_unlock(&rt_b->rt_runtime_lock);
73}
74
75#if defined(CONFIG_SMP) && defined(HAVE_RT_PUSH_IPI)
76static void push_irq_work_func(struct irq_work *work);
77#endif
78
79void init_rt_rq(struct rt_rq *rt_rq)
80{
81 struct rt_prio_array *array;
82 int i;
83
84 array = &rt_rq->active;
85 for (i = 0; i < MAX_RT_PRIO; i++) {
86 INIT_LIST_HEAD(array->queue + i);
87 __clear_bit(i, array->bitmap);
88 }
89 /* delimiter for bitsearch: */
90 __set_bit(MAX_RT_PRIO, array->bitmap);
91
92#if defined CONFIG_SMP
93 rt_rq->highest_prio.curr = MAX_RT_PRIO;
94 rt_rq->highest_prio.next = MAX_RT_PRIO;
95 rt_rq->rt_nr_migratory = 0;
96 rt_rq->overloaded = 0;
97 plist_head_init(&rt_rq->pushable_tasks);
98
99#ifdef HAVE_RT_PUSH_IPI
100 rt_rq->push_flags = 0;
101 rt_rq->push_cpu = nr_cpu_ids;
102 raw_spin_lock_init(&rt_rq->push_lock);
103 init_irq_work(&rt_rq->push_work, push_irq_work_func);
104#endif
105#endif /* CONFIG_SMP */
106 /* We start is dequeued state, because no RT tasks are queued */
107 rt_rq->rt_queued = 0;
108
109 rt_rq->rt_time = 0;
110 rt_rq->rt_throttled = 0;
111 rt_rq->rt_runtime = 0;
112 raw_spin_lock_init(&rt_rq->rt_runtime_lock);
113}
114
115#ifdef CONFIG_RT_GROUP_SCHED
116static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b)
117{
118 hrtimer_cancel(&rt_b->rt_period_timer);
119}
120
121#define rt_entity_is_task(rt_se) (!(rt_se)->my_q)
122
123static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
124{
125#ifdef CONFIG_SCHED_DEBUG
126 WARN_ON_ONCE(!rt_entity_is_task(rt_se));
127#endif
128 return container_of(rt_se, struct task_struct, rt);
129}
130
131static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
132{
133 return rt_rq->rq;
134}
135
136static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
137{
138 return rt_se->rt_rq;
139}
140
141static inline struct rq *rq_of_rt_se(struct sched_rt_entity *rt_se)
142{
143 struct rt_rq *rt_rq = rt_se->rt_rq;
144
145 return rt_rq->rq;
146}
147
148void free_rt_sched_group(struct task_group *tg)
149{
150 int i;
151
152 if (tg->rt_se)
153 destroy_rt_bandwidth(&tg->rt_bandwidth);
154
155 for_each_possible_cpu(i) {
156 if (tg->rt_rq)
157 kfree(tg->rt_rq[i]);
158 if (tg->rt_se)
159 kfree(tg->rt_se[i]);
160 }
161
162 kfree(tg->rt_rq);
163 kfree(tg->rt_se);
164}
165
166void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
167 struct sched_rt_entity *rt_se, int cpu,
168 struct sched_rt_entity *parent)
169{
170 struct rq *rq = cpu_rq(cpu);
171
172 rt_rq->highest_prio.curr = MAX_RT_PRIO;
173 rt_rq->rt_nr_boosted = 0;
174 rt_rq->rq = rq;
175 rt_rq->tg = tg;
176
177 tg->rt_rq[cpu] = rt_rq;
178 tg->rt_se[cpu] = rt_se;
179
180 if (!rt_se)
181 return;
182
183 if (!parent)
184 rt_se->rt_rq = &rq->rt;
185 else
186 rt_se->rt_rq = parent->my_q;
187
188 rt_se->my_q = rt_rq;
189 rt_se->parent = parent;
190 INIT_LIST_HEAD(&rt_se->run_list);
191}
192
193int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
194{
195 struct rt_rq *rt_rq;
196 struct sched_rt_entity *rt_se;
197 int i;
198
199 tg->rt_rq = kzalloc(sizeof(rt_rq) * nr_cpu_ids, GFP_KERNEL);
200 if (!tg->rt_rq)
201 goto err;
202 tg->rt_se = kzalloc(sizeof(rt_se) * nr_cpu_ids, GFP_KERNEL);
203 if (!tg->rt_se)
204 goto err;
205
206 init_rt_bandwidth(&tg->rt_bandwidth,
207 ktime_to_ns(def_rt_bandwidth.rt_period), 0);
208
209 for_each_possible_cpu(i) {
210 rt_rq = kzalloc_node(sizeof(struct rt_rq),
211 GFP_KERNEL, cpu_to_node(i));
212 if (!rt_rq)
213 goto err;
214
215 rt_se = kzalloc_node(sizeof(struct sched_rt_entity),
216 GFP_KERNEL, cpu_to_node(i));
217 if (!rt_se)
218 goto err_free_rq;
219
220 init_rt_rq(rt_rq);
221 rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime;
222 init_tg_rt_entry(tg, rt_rq, rt_se, i, parent->rt_se[i]);
223 }
224
225 return 1;
226
227err_free_rq:
228 kfree(rt_rq);
229err:
230 return 0;
231}
232
233#else /* CONFIG_RT_GROUP_SCHED */
234
235#define rt_entity_is_task(rt_se) (1)
236
237static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
238{
239 return container_of(rt_se, struct task_struct, rt);
240}
241
242static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
243{
244 return container_of(rt_rq, struct rq, rt);
245}
246
247static inline struct rq *rq_of_rt_se(struct sched_rt_entity *rt_se)
248{
249 struct task_struct *p = rt_task_of(rt_se);
250
251 return task_rq(p);
252}
253
254static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
255{
256 struct rq *rq = rq_of_rt_se(rt_se);
257
258 return &rq->rt;
259}
260
261void free_rt_sched_group(struct task_group *tg) { }
262
263int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
264{
265 return 1;
266}
267#endif /* CONFIG_RT_GROUP_SCHED */
268
269#ifdef CONFIG_SMP
270
271static void pull_rt_task(struct rq *this_rq);
272
273static inline bool need_pull_rt_task(struct rq *rq, struct task_struct *prev)
274{
275 /* Try to pull RT tasks here if we lower this rq's prio */
276 return rq->rt.highest_prio.curr > prev->prio;
277}
278
279static inline int rt_overloaded(struct rq *rq)
280{
281 return atomic_read(&rq->rd->rto_count);
282}
283
284static inline void rt_set_overload(struct rq *rq)
285{
286 if (!rq->online)
287 return;
288
289 cpumask_set_cpu(rq->cpu, rq->rd->rto_mask);
290 /*
291 * Make sure the mask is visible before we set
292 * the overload count. That is checked to determine
293 * if we should look at the mask. It would be a shame
294 * if we looked at the mask, but the mask was not
295 * updated yet.
296 *
297 * Matched by the barrier in pull_rt_task().
298 */
299 smp_wmb();
300 atomic_inc(&rq->rd->rto_count);
301}
302
303static inline void rt_clear_overload(struct rq *rq)
304{
305 if (!rq->online)
306 return;
307
308 /* the order here really doesn't matter */
309 atomic_dec(&rq->rd->rto_count);
310 cpumask_clear_cpu(rq->cpu, rq->rd->rto_mask);
311}
312
313static void update_rt_migration(struct rt_rq *rt_rq)
314{
315 if (rt_rq->rt_nr_migratory && rt_rq->rt_nr_total > 1) {
316 if (!rt_rq->overloaded) {
317 rt_set_overload(rq_of_rt_rq(rt_rq));
318 rt_rq->overloaded = 1;
319 }
320 } else if (rt_rq->overloaded) {
321 rt_clear_overload(rq_of_rt_rq(rt_rq));
322 rt_rq->overloaded = 0;
323 }
324}
325
326static void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
327{
328 struct task_struct *p;
329
330 if (!rt_entity_is_task(rt_se))
331 return;
332
333 p = rt_task_of(rt_se);
334 rt_rq = &rq_of_rt_rq(rt_rq)->rt;
335
336 rt_rq->rt_nr_total++;
337 if (p->nr_cpus_allowed > 1)
338 rt_rq->rt_nr_migratory++;
339
340 update_rt_migration(rt_rq);
341}
342
343static void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
344{
345 struct task_struct *p;
346
347 if (!rt_entity_is_task(rt_se))
348 return;
349
350 p = rt_task_of(rt_se);
351 rt_rq = &rq_of_rt_rq(rt_rq)->rt;
352
353 rt_rq->rt_nr_total--;
354 if (p->nr_cpus_allowed > 1)
355 rt_rq->rt_nr_migratory--;
356
357 update_rt_migration(rt_rq);
358}
359
360static inline int has_pushable_tasks(struct rq *rq)
361{
362 return !plist_head_empty(&rq->rt.pushable_tasks);
363}
364
365static DEFINE_PER_CPU(struct callback_head, rt_push_head);
366static DEFINE_PER_CPU(struct callback_head, rt_pull_head);
367
368static void push_rt_tasks(struct rq *);
369static void pull_rt_task(struct rq *);
370
371static inline void queue_push_tasks(struct rq *rq)
372{
373 if (!has_pushable_tasks(rq))
374 return;
375
376 queue_balance_callback(rq, &per_cpu(rt_push_head, rq->cpu), push_rt_tasks);
377}
378
379static inline void queue_pull_task(struct rq *rq)
380{
381 queue_balance_callback(rq, &per_cpu(rt_pull_head, rq->cpu), pull_rt_task);
382}
383
384static void enqueue_pushable_task(struct rq *rq, struct task_struct *p)
385{
386 plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks);
387 plist_node_init(&p->pushable_tasks, p->prio);
388 plist_add(&p->pushable_tasks, &rq->rt.pushable_tasks);
389
390 /* Update the highest prio pushable task */
391 if (p->prio < rq->rt.highest_prio.next)
392 rq->rt.highest_prio.next = p->prio;
393}
394
395static void dequeue_pushable_task(struct rq *rq, struct task_struct *p)
396{
397 plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks);
398
399 /* Update the new highest prio pushable task */
400 if (has_pushable_tasks(rq)) {
401 p = plist_first_entry(&rq->rt.pushable_tasks,
402 struct task_struct, pushable_tasks);
403 rq->rt.highest_prio.next = p->prio;
404 } else
405 rq->rt.highest_prio.next = MAX_RT_PRIO;
406}
407
408#else
409
410static inline void enqueue_pushable_task(struct rq *rq, struct task_struct *p)
411{
412}
413
414static inline void dequeue_pushable_task(struct rq *rq, struct task_struct *p)
415{
416}
417
418static inline
419void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
420{
421}
422
423static inline
424void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
425{
426}
427
428static inline bool need_pull_rt_task(struct rq *rq, struct task_struct *prev)
429{
430 return false;
431}
432
433static inline void pull_rt_task(struct rq *this_rq)
434{
435}
436
437static inline void queue_push_tasks(struct rq *rq)
438{
439}
440#endif /* CONFIG_SMP */
441
442static void enqueue_top_rt_rq(struct rt_rq *rt_rq);
443static void dequeue_top_rt_rq(struct rt_rq *rt_rq);
444
445static inline int on_rt_rq(struct sched_rt_entity *rt_se)
446{
447 return rt_se->on_rq;
448}
449
450#ifdef CONFIG_RT_GROUP_SCHED
451
452static inline u64 sched_rt_runtime(struct rt_rq *rt_rq)
453{
454 if (!rt_rq->tg)
455 return RUNTIME_INF;
456
457 return rt_rq->rt_runtime;
458}
459
460static inline u64 sched_rt_period(struct rt_rq *rt_rq)
461{
462 return ktime_to_ns(rt_rq->tg->rt_bandwidth.rt_period);
463}
464
465typedef struct task_group *rt_rq_iter_t;
466
467static inline struct task_group *next_task_group(struct task_group *tg)
468{
469 do {
470 tg = list_entry_rcu(tg->list.next,
471 typeof(struct task_group), list);
472 } while (&tg->list != &task_groups && task_group_is_autogroup(tg));
473
474 if (&tg->list == &task_groups)
475 tg = NULL;
476
477 return tg;
478}
479
480#define for_each_rt_rq(rt_rq, iter, rq) \
481 for (iter = container_of(&task_groups, typeof(*iter), list); \
482 (iter = next_task_group(iter)) && \
483 (rt_rq = iter->rt_rq[cpu_of(rq)]);)
484
485#define for_each_sched_rt_entity(rt_se) \
486 for (; rt_se; rt_se = rt_se->parent)
487
488static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
489{
490 return rt_se->my_q;
491}
492
493static void enqueue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags);
494static void dequeue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags);
495
496static void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
497{
498 struct task_struct *curr = rq_of_rt_rq(rt_rq)->curr;
499 struct rq *rq = rq_of_rt_rq(rt_rq);
500 struct sched_rt_entity *rt_se;
501
502 int cpu = cpu_of(rq);
503
504 rt_se = rt_rq->tg->rt_se[cpu];
505
506 if (rt_rq->rt_nr_running) {
507 if (!rt_se)
508 enqueue_top_rt_rq(rt_rq);
509 else if (!on_rt_rq(rt_se))
510 enqueue_rt_entity(rt_se, 0);
511
512 if (rt_rq->highest_prio.curr < curr->prio)
513 resched_curr(rq);
514 }
515}
516
517static void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
518{
519 struct sched_rt_entity *rt_se;
520 int cpu = cpu_of(rq_of_rt_rq(rt_rq));
521
522 rt_se = rt_rq->tg->rt_se[cpu];
523
524 if (!rt_se)
525 dequeue_top_rt_rq(rt_rq);
526 else if (on_rt_rq(rt_se))
527 dequeue_rt_entity(rt_se, 0);
528}
529
530static inline int rt_rq_throttled(struct rt_rq *rt_rq)
531{
532 return rt_rq->rt_throttled && !rt_rq->rt_nr_boosted;
533}
534
535static int rt_se_boosted(struct sched_rt_entity *rt_se)
536{
537 struct rt_rq *rt_rq = group_rt_rq(rt_se);
538 struct task_struct *p;
539
540 if (rt_rq)
541 return !!rt_rq->rt_nr_boosted;
542
543 p = rt_task_of(rt_se);
544 return p->prio != p->normal_prio;
545}
546
547#ifdef CONFIG_SMP
548static inline const struct cpumask *sched_rt_period_mask(void)
549{
550 return this_rq()->rd->span;
551}
552#else
553static inline const struct cpumask *sched_rt_period_mask(void)
554{
555 return cpu_online_mask;
556}
557#endif
558
559static inline
560struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu)
561{
562 return container_of(rt_b, struct task_group, rt_bandwidth)->rt_rq[cpu];
563}
564
565static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
566{
567 return &rt_rq->tg->rt_bandwidth;
568}
569
570#else /* !CONFIG_RT_GROUP_SCHED */
571
572static inline u64 sched_rt_runtime(struct rt_rq *rt_rq)
573{
574 return rt_rq->rt_runtime;
575}
576
577static inline u64 sched_rt_period(struct rt_rq *rt_rq)
578{
579 return ktime_to_ns(def_rt_bandwidth.rt_period);
580}
581
582typedef struct rt_rq *rt_rq_iter_t;
583
584#define for_each_rt_rq(rt_rq, iter, rq) \
585 for ((void) iter, rt_rq = &rq->rt; rt_rq; rt_rq = NULL)
586
587#define for_each_sched_rt_entity(rt_se) \
588 for (; rt_se; rt_se = NULL)
589
590static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
591{
592 return NULL;
593}
594
595static inline void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
596{
597 struct rq *rq = rq_of_rt_rq(rt_rq);
598
599 if (!rt_rq->rt_nr_running)
600 return;
601
602 enqueue_top_rt_rq(rt_rq);
603 resched_curr(rq);
604}
605
606static inline void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
607{
608 dequeue_top_rt_rq(rt_rq);
609}
610
611static inline int rt_rq_throttled(struct rt_rq *rt_rq)
612{
613 return rt_rq->rt_throttled;
614}
615
616static inline const struct cpumask *sched_rt_period_mask(void)
617{
618 return cpu_online_mask;
619}
620
621static inline
622struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu)
623{
624 return &cpu_rq(cpu)->rt;
625}
626
627static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
628{
629 return &def_rt_bandwidth;
630}
631
632#endif /* CONFIG_RT_GROUP_SCHED */
633
634bool sched_rt_bandwidth_account(struct rt_rq *rt_rq)
635{
636 struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
637
638 return (hrtimer_active(&rt_b->rt_period_timer) ||
639 rt_rq->rt_time < rt_b->rt_runtime);
640}
641
642#ifdef CONFIG_SMP
643/*
644 * We ran out of runtime, see if we can borrow some from our neighbours.
645 */
646static void do_balance_runtime(struct rt_rq *rt_rq)
647{
648 struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
649 struct root_domain *rd = rq_of_rt_rq(rt_rq)->rd;
650 int i, weight;
651 u64 rt_period;
652
653 weight = cpumask_weight(rd->span);
654
655 raw_spin_lock(&rt_b->rt_runtime_lock);
656 rt_period = ktime_to_ns(rt_b->rt_period);
657 for_each_cpu(i, rd->span) {
658 struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
659 s64 diff;
660
661 if (iter == rt_rq)
662 continue;
663
664 raw_spin_lock(&iter->rt_runtime_lock);
665 /*
666 * Either all rqs have inf runtime and there's nothing to steal
667 * or __disable_runtime() below sets a specific rq to inf to
668 * indicate its been disabled and disalow stealing.
669 */
670 if (iter->rt_runtime == RUNTIME_INF)
671 goto next;
672
673 /*
674 * From runqueues with spare time, take 1/n part of their
675 * spare time, but no more than our period.
676 */
677 diff = iter->rt_runtime - iter->rt_time;
678 if (diff > 0) {
679 diff = div_u64((u64)diff, weight);
680 if (rt_rq->rt_runtime + diff > rt_period)
681 diff = rt_period - rt_rq->rt_runtime;
682 iter->rt_runtime -= diff;
683 rt_rq->rt_runtime += diff;
684 if (rt_rq->rt_runtime == rt_period) {
685 raw_spin_unlock(&iter->rt_runtime_lock);
686 break;
687 }
688 }
689next:
690 raw_spin_unlock(&iter->rt_runtime_lock);
691 }
692 raw_spin_unlock(&rt_b->rt_runtime_lock);
693}
694
695/*
696 * Ensure this RQ takes back all the runtime it lend to its neighbours.
697 */
698static void __disable_runtime(struct rq *rq)
699{
700 struct root_domain *rd = rq->rd;
701 rt_rq_iter_t iter;
702 struct rt_rq *rt_rq;
703
704 if (unlikely(!scheduler_running))
705 return;
706
707 for_each_rt_rq(rt_rq, iter, rq) {
708 struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
709 s64 want;
710 int i;
711
712 raw_spin_lock(&rt_b->rt_runtime_lock);
713 raw_spin_lock(&rt_rq->rt_runtime_lock);
714 /*
715 * Either we're all inf and nobody needs to borrow, or we're
716 * already disabled and thus have nothing to do, or we have
717 * exactly the right amount of runtime to take out.
718 */
719 if (rt_rq->rt_runtime == RUNTIME_INF ||
720 rt_rq->rt_runtime == rt_b->rt_runtime)
721 goto balanced;
722 raw_spin_unlock(&rt_rq->rt_runtime_lock);
723
724 /*
725 * Calculate the difference between what we started out with
726 * and what we current have, that's the amount of runtime
727 * we lend and now have to reclaim.
728 */
729 want = rt_b->rt_runtime - rt_rq->rt_runtime;
730
731 /*
732 * Greedy reclaim, take back as much as we can.
733 */
734 for_each_cpu(i, rd->span) {
735 struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
736 s64 diff;
737
738 /*
739 * Can't reclaim from ourselves or disabled runqueues.
740 */
741 if (iter == rt_rq || iter->rt_runtime == RUNTIME_INF)
742 continue;
743
744 raw_spin_lock(&iter->rt_runtime_lock);
745 if (want > 0) {
746 diff = min_t(s64, iter->rt_runtime, want);
747 iter->rt_runtime -= diff;
748 want -= diff;
749 } else {
750 iter->rt_runtime -= want;
751 want -= want;
752 }
753 raw_spin_unlock(&iter->rt_runtime_lock);
754
755 if (!want)
756 break;
757 }
758
759 raw_spin_lock(&rt_rq->rt_runtime_lock);
760 /*
761 * We cannot be left wanting - that would mean some runtime
762 * leaked out of the system.
763 */
764 BUG_ON(want);
765balanced:
766 /*
767 * Disable all the borrow logic by pretending we have inf
768 * runtime - in which case borrowing doesn't make sense.
769 */
770 rt_rq->rt_runtime = RUNTIME_INF;
771 rt_rq->rt_throttled = 0;
772 raw_spin_unlock(&rt_rq->rt_runtime_lock);
773 raw_spin_unlock(&rt_b->rt_runtime_lock);
774
775 /* Make rt_rq available for pick_next_task() */
776 sched_rt_rq_enqueue(rt_rq);
777 }
778}
779
780static void __enable_runtime(struct rq *rq)
781{
782 rt_rq_iter_t iter;
783 struct rt_rq *rt_rq;
784
785 if (unlikely(!scheduler_running))
786 return;
787
788 /*
789 * Reset each runqueue's bandwidth settings
790 */
791 for_each_rt_rq(rt_rq, iter, rq) {
792 struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
793
794 raw_spin_lock(&rt_b->rt_runtime_lock);
795 raw_spin_lock(&rt_rq->rt_runtime_lock);
796 rt_rq->rt_runtime = rt_b->rt_runtime;
797 rt_rq->rt_time = 0;
798 rt_rq->rt_throttled = 0;
799 raw_spin_unlock(&rt_rq->rt_runtime_lock);
800 raw_spin_unlock(&rt_b->rt_runtime_lock);
801 }
802}
803
804static void balance_runtime(struct rt_rq *rt_rq)
805{
806 if (!sched_feat(RT_RUNTIME_SHARE))
807 return;
808
809 if (rt_rq->rt_time > rt_rq->rt_runtime) {
810 raw_spin_unlock(&rt_rq->rt_runtime_lock);
811 do_balance_runtime(rt_rq);
812 raw_spin_lock(&rt_rq->rt_runtime_lock);
813 }
814}
815#else /* !CONFIG_SMP */
816static inline void balance_runtime(struct rt_rq *rt_rq) {}
817#endif /* CONFIG_SMP */
818
819static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
820{
821 int i, idle = 1, throttled = 0;
822 const struct cpumask *span;
823
824 span = sched_rt_period_mask();
825#ifdef CONFIG_RT_GROUP_SCHED
826 /*
827 * FIXME: isolated CPUs should really leave the root task group,
828 * whether they are isolcpus or were isolated via cpusets, lest
829 * the timer run on a CPU which does not service all runqueues,
830 * potentially leaving other CPUs indefinitely throttled. If
831 * isolation is really required, the user will turn the throttle
832 * off to kill the perturbations it causes anyway. Meanwhile,
833 * this maintains functionality for boot and/or troubleshooting.
834 */
835 if (rt_b == &root_task_group.rt_bandwidth)
836 span = cpu_online_mask;
837#endif
838 for_each_cpu(i, span) {
839 int enqueue = 0;
840 struct rt_rq *rt_rq = sched_rt_period_rt_rq(rt_b, i);
841 struct rq *rq = rq_of_rt_rq(rt_rq);
842
843 raw_spin_lock(&rq->lock);
844 if (rt_rq->rt_time) {
845 u64 runtime;
846
847 raw_spin_lock(&rt_rq->rt_runtime_lock);
848 if (rt_rq->rt_throttled)
849 balance_runtime(rt_rq);
850 runtime = rt_rq->rt_runtime;
851 rt_rq->rt_time -= min(rt_rq->rt_time, overrun*runtime);
852 if (rt_rq->rt_throttled && rt_rq->rt_time < runtime) {
853 rt_rq->rt_throttled = 0;
854 enqueue = 1;
855
856 /*
857 * When we're idle and a woken (rt) task is
858 * throttled check_preempt_curr() will set
859 * skip_update and the time between the wakeup
860 * and this unthrottle will get accounted as
861 * 'runtime'.
862 */
863 if (rt_rq->rt_nr_running && rq->curr == rq->idle)
864 rq_clock_skip_update(rq, false);
865 }
866 if (rt_rq->rt_time || rt_rq->rt_nr_running)
867 idle = 0;
868 raw_spin_unlock(&rt_rq->rt_runtime_lock);
869 } else if (rt_rq->rt_nr_running) {
870 idle = 0;
871 if (!rt_rq_throttled(rt_rq))
872 enqueue = 1;
873 }
874 if (rt_rq->rt_throttled)
875 throttled = 1;
876
877 if (enqueue)
878 sched_rt_rq_enqueue(rt_rq);
879 raw_spin_unlock(&rq->lock);
880 }
881
882 if (!throttled && (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF))
883 return 1;
884
885 return idle;
886}
887
888static inline int rt_se_prio(struct sched_rt_entity *rt_se)
889{
890#ifdef CONFIG_RT_GROUP_SCHED
891 struct rt_rq *rt_rq = group_rt_rq(rt_se);
892
893 if (rt_rq)
894 return rt_rq->highest_prio.curr;
895#endif
896
897 return rt_task_of(rt_se)->prio;
898}
899
900static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq)
901{
902 u64 runtime = sched_rt_runtime(rt_rq);
903
904 if (rt_rq->rt_throttled)
905 return rt_rq_throttled(rt_rq);
906
907 if (runtime >= sched_rt_period(rt_rq))
908 return 0;
909
910 balance_runtime(rt_rq);
911 runtime = sched_rt_runtime(rt_rq);
912 if (runtime == RUNTIME_INF)
913 return 0;
914
915 if (rt_rq->rt_time > runtime) {
916 struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
917
918 /*
919 * Don't actually throttle groups that have no runtime assigned
920 * but accrue some time due to boosting.
921 */
922 if (likely(rt_b->rt_runtime)) {
923 rt_rq->rt_throttled = 1;
924 printk_deferred_once("sched: RT throttling activated\n");
925 } else {
926 /*
927 * In case we did anyway, make it go away,
928 * replenishment is a joke, since it will replenish us
929 * with exactly 0 ns.
930 */
931 rt_rq->rt_time = 0;
932 }
933
934 if (rt_rq_throttled(rt_rq)) {
935 sched_rt_rq_dequeue(rt_rq);
936 return 1;
937 }
938 }
939
940 return 0;
941}
942
943/*
944 * Update the current task's runtime statistics. Skip current tasks that
945 * are not in our scheduling class.
946 */
947static void update_curr_rt(struct rq *rq)
948{
949 struct task_struct *curr = rq->curr;
950 struct sched_rt_entity *rt_se = &curr->rt;
951 u64 delta_exec;
952
953 if (curr->sched_class != &rt_sched_class)
954 return;
955
956 /* Kick cpufreq (see the comment in linux/cpufreq.h). */
957 if (cpu_of(rq) == smp_processor_id())
958 cpufreq_trigger_update(rq_clock(rq));
959
960 delta_exec = rq_clock_task(rq) - curr->se.exec_start;
961 if (unlikely((s64)delta_exec <= 0))
962 return;
963
964 schedstat_set(curr->se.statistics.exec_max,
965 max(curr->se.statistics.exec_max, delta_exec));
966
967 curr->se.sum_exec_runtime += delta_exec;
968 account_group_exec_runtime(curr, delta_exec);
969
970 curr->se.exec_start = rq_clock_task(rq);
971 cpuacct_charge(curr, delta_exec);
972
973 sched_rt_avg_update(rq, delta_exec);
974
975 if (!rt_bandwidth_enabled())
976 return;
977
978 for_each_sched_rt_entity(rt_se) {
979 struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
980
981 if (sched_rt_runtime(rt_rq) != RUNTIME_INF) {
982 raw_spin_lock(&rt_rq->rt_runtime_lock);
983 rt_rq->rt_time += delta_exec;
984 if (sched_rt_runtime_exceeded(rt_rq))
985 resched_curr(rq);
986 raw_spin_unlock(&rt_rq->rt_runtime_lock);
987 }
988 }
989}
990
991static void
992dequeue_top_rt_rq(struct rt_rq *rt_rq)
993{
994 struct rq *rq = rq_of_rt_rq(rt_rq);
995
996 BUG_ON(&rq->rt != rt_rq);
997
998 if (!rt_rq->rt_queued)
999 return;
1000
1001 BUG_ON(!rq->nr_running);
1002
1003 sub_nr_running(rq, rt_rq->rt_nr_running);
1004 rt_rq->rt_queued = 0;
1005}
1006
1007static void
1008enqueue_top_rt_rq(struct rt_rq *rt_rq)
1009{
1010 struct rq *rq = rq_of_rt_rq(rt_rq);
1011
1012 BUG_ON(&rq->rt != rt_rq);
1013
1014 if (rt_rq->rt_queued)
1015 return;
1016 if (rt_rq_throttled(rt_rq) || !rt_rq->rt_nr_running)
1017 return;
1018
1019 add_nr_running(rq, rt_rq->rt_nr_running);
1020 rt_rq->rt_queued = 1;
1021}
1022
1023#if defined CONFIG_SMP
1024
1025static void
1026inc_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio)
1027{
1028 struct rq *rq = rq_of_rt_rq(rt_rq);
1029
1030#ifdef CONFIG_RT_GROUP_SCHED
1031 /*
1032 * Change rq's cpupri only if rt_rq is the top queue.
1033 */
1034 if (&rq->rt != rt_rq)
1035 return;
1036#endif
1037 if (rq->online && prio < prev_prio)
1038 cpupri_set(&rq->rd->cpupri, rq->cpu, prio);
1039}
1040
1041static void
1042dec_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio)
1043{
1044 struct rq *rq = rq_of_rt_rq(rt_rq);
1045
1046#ifdef CONFIG_RT_GROUP_SCHED
1047 /*
1048 * Change rq's cpupri only if rt_rq is the top queue.
1049 */
1050 if (&rq->rt != rt_rq)
1051 return;
1052#endif
1053 if (rq->online && rt_rq->highest_prio.curr != prev_prio)
1054 cpupri_set(&rq->rd->cpupri, rq->cpu, rt_rq->highest_prio.curr);
1055}
1056
1057#else /* CONFIG_SMP */
1058
1059static inline
1060void inc_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio) {}
1061static inline
1062void dec_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio) {}
1063
1064#endif /* CONFIG_SMP */
1065
1066#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
1067static void
1068inc_rt_prio(struct rt_rq *rt_rq, int prio)
1069{
1070 int prev_prio = rt_rq->highest_prio.curr;
1071
1072 if (prio < prev_prio)
1073 rt_rq->highest_prio.curr = prio;
1074
1075 inc_rt_prio_smp(rt_rq, prio, prev_prio);
1076}
1077
1078static void
1079dec_rt_prio(struct rt_rq *rt_rq, int prio)
1080{
1081 int prev_prio = rt_rq->highest_prio.curr;
1082
1083 if (rt_rq->rt_nr_running) {
1084
1085 WARN_ON(prio < prev_prio);
1086
1087 /*
1088 * This may have been our highest task, and therefore
1089 * we may have some recomputation to do
1090 */
1091 if (prio == prev_prio) {
1092 struct rt_prio_array *array = &rt_rq->active;
1093
1094 rt_rq->highest_prio.curr =
1095 sched_find_first_bit(array->bitmap);
1096 }
1097
1098 } else
1099 rt_rq->highest_prio.curr = MAX_RT_PRIO;
1100
1101 dec_rt_prio_smp(rt_rq, prio, prev_prio);
1102}
1103
1104#else
1105
1106static inline void inc_rt_prio(struct rt_rq *rt_rq, int prio) {}
1107static inline void dec_rt_prio(struct rt_rq *rt_rq, int prio) {}
1108
1109#endif /* CONFIG_SMP || CONFIG_RT_GROUP_SCHED */
1110
1111#ifdef CONFIG_RT_GROUP_SCHED
1112
1113static void
1114inc_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
1115{
1116 if (rt_se_boosted(rt_se))
1117 rt_rq->rt_nr_boosted++;
1118
1119 if (rt_rq->tg)
1120 start_rt_bandwidth(&rt_rq->tg->rt_bandwidth);
1121}
1122
1123static void
1124dec_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
1125{
1126 if (rt_se_boosted(rt_se))
1127 rt_rq->rt_nr_boosted--;
1128
1129 WARN_ON(!rt_rq->rt_nr_running && rt_rq->rt_nr_boosted);
1130}
1131
1132#else /* CONFIG_RT_GROUP_SCHED */
1133
1134static void
1135inc_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
1136{
1137 start_rt_bandwidth(&def_rt_bandwidth);
1138}
1139
1140static inline
1141void dec_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) {}
1142
1143#endif /* CONFIG_RT_GROUP_SCHED */
1144
1145static inline
1146unsigned int rt_se_nr_running(struct sched_rt_entity *rt_se)
1147{
1148 struct rt_rq *group_rq = group_rt_rq(rt_se);
1149
1150 if (group_rq)
1151 return group_rq->rt_nr_running;
1152 else
1153 return 1;
1154}
1155
1156static inline
1157unsigned int rt_se_rr_nr_running(struct sched_rt_entity *rt_se)
1158{
1159 struct rt_rq *group_rq = group_rt_rq(rt_se);
1160 struct task_struct *tsk;
1161
1162 if (group_rq)
1163 return group_rq->rr_nr_running;
1164
1165 tsk = rt_task_of(rt_se);
1166
1167 return (tsk->policy == SCHED_RR) ? 1 : 0;
1168}
1169
1170static inline
1171void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
1172{
1173 int prio = rt_se_prio(rt_se);
1174
1175 WARN_ON(!rt_prio(prio));
1176 rt_rq->rt_nr_running += rt_se_nr_running(rt_se);
1177 rt_rq->rr_nr_running += rt_se_rr_nr_running(rt_se);
1178
1179 inc_rt_prio(rt_rq, prio);
1180 inc_rt_migration(rt_se, rt_rq);
1181 inc_rt_group(rt_se, rt_rq);
1182}
1183
1184static inline
1185void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
1186{
1187 WARN_ON(!rt_prio(rt_se_prio(rt_se)));
1188 WARN_ON(!rt_rq->rt_nr_running);
1189 rt_rq->rt_nr_running -= rt_se_nr_running(rt_se);
1190 rt_rq->rr_nr_running -= rt_se_rr_nr_running(rt_se);
1191
1192 dec_rt_prio(rt_rq, rt_se_prio(rt_se));
1193 dec_rt_migration(rt_se, rt_rq);
1194 dec_rt_group(rt_se, rt_rq);
1195}
1196
1197/*
1198 * Change rt_se->run_list location unless SAVE && !MOVE
1199 *
1200 * assumes ENQUEUE/DEQUEUE flags match
1201 */
1202static inline bool move_entity(unsigned int flags)
1203{
1204 if ((flags & (DEQUEUE_SAVE | DEQUEUE_MOVE)) == DEQUEUE_SAVE)
1205 return false;
1206
1207 return true;
1208}
1209
1210static void __delist_rt_entity(struct sched_rt_entity *rt_se, struct rt_prio_array *array)
1211{
1212 list_del_init(&rt_se->run_list);
1213
1214 if (list_empty(array->queue + rt_se_prio(rt_se)))
1215 __clear_bit(rt_se_prio(rt_se), array->bitmap);
1216
1217 rt_se->on_list = 0;
1218}
1219
1220static void __enqueue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags)
1221{
1222 struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
1223 struct rt_prio_array *array = &rt_rq->active;
1224 struct rt_rq *group_rq = group_rt_rq(rt_se);
1225 struct list_head *queue = array->queue + rt_se_prio(rt_se);
1226
1227 /*
1228 * Don't enqueue the group if its throttled, or when empty.
1229 * The latter is a consequence of the former when a child group
1230 * get throttled and the current group doesn't have any other
1231 * active members.
1232 */
1233 if (group_rq && (rt_rq_throttled(group_rq) || !group_rq->rt_nr_running)) {
1234 if (rt_se->on_list)
1235 __delist_rt_entity(rt_se, array);
1236 return;
1237 }
1238
1239 if (move_entity(flags)) {
1240 WARN_ON_ONCE(rt_se->on_list);
1241 if (flags & ENQUEUE_HEAD)
1242 list_add(&rt_se->run_list, queue);
1243 else
1244 list_add_tail(&rt_se->run_list, queue);
1245
1246 __set_bit(rt_se_prio(rt_se), array->bitmap);
1247 rt_se->on_list = 1;
1248 }
1249 rt_se->on_rq = 1;
1250
1251 inc_rt_tasks(rt_se, rt_rq);
1252}
1253
1254static void __dequeue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags)
1255{
1256 struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
1257 struct rt_prio_array *array = &rt_rq->active;
1258
1259 if (move_entity(flags)) {
1260 WARN_ON_ONCE(!rt_se->on_list);
1261 __delist_rt_entity(rt_se, array);
1262 }
1263 rt_se->on_rq = 0;
1264
1265 dec_rt_tasks(rt_se, rt_rq);
1266}
1267
1268/*
1269 * Because the prio of an upper entry depends on the lower
1270 * entries, we must remove entries top - down.
1271 */
1272static void dequeue_rt_stack(struct sched_rt_entity *rt_se, unsigned int flags)
1273{
1274 struct sched_rt_entity *back = NULL;
1275
1276 for_each_sched_rt_entity(rt_se) {
1277 rt_se->back = back;
1278 back = rt_se;
1279 }
1280
1281 dequeue_top_rt_rq(rt_rq_of_se(back));
1282
1283 for (rt_se = back; rt_se; rt_se = rt_se->back) {
1284 if (on_rt_rq(rt_se))
1285 __dequeue_rt_entity(rt_se, flags);
1286 }
1287}
1288
1289static void enqueue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags)
1290{
1291 struct rq *rq = rq_of_rt_se(rt_se);
1292
1293 dequeue_rt_stack(rt_se, flags);
1294 for_each_sched_rt_entity(rt_se)
1295 __enqueue_rt_entity(rt_se, flags);
1296 enqueue_top_rt_rq(&rq->rt);
1297}
1298
1299static void dequeue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags)
1300{
1301 struct rq *rq = rq_of_rt_se(rt_se);
1302
1303 dequeue_rt_stack(rt_se, flags);
1304
1305 for_each_sched_rt_entity(rt_se) {
1306 struct rt_rq *rt_rq = group_rt_rq(rt_se);
1307
1308 if (rt_rq && rt_rq->rt_nr_running)
1309 __enqueue_rt_entity(rt_se, flags);
1310 }
1311 enqueue_top_rt_rq(&rq->rt);
1312}
1313
1314/*
1315 * Adding/removing a task to/from a priority array:
1316 */
1317static void
1318enqueue_task_rt(struct rq *rq, struct task_struct *p, int flags)
1319{
1320 struct sched_rt_entity *rt_se = &p->rt;
1321
1322 if (flags & ENQUEUE_WAKEUP)
1323 rt_se->timeout = 0;
1324
1325 enqueue_rt_entity(rt_se, flags);
1326
1327 if (!task_current(rq, p) && p->nr_cpus_allowed > 1)
1328 enqueue_pushable_task(rq, p);
1329}
1330
1331static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int flags)
1332{
1333 struct sched_rt_entity *rt_se = &p->rt;
1334
1335 update_curr_rt(rq);
1336 dequeue_rt_entity(rt_se, flags);
1337
1338 dequeue_pushable_task(rq, p);
1339}
1340
1341/*
1342 * Put task to the head or the end of the run list without the overhead of
1343 * dequeue followed by enqueue.
1344 */
1345static void
1346requeue_rt_entity(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se, int head)
1347{
1348 if (on_rt_rq(rt_se)) {
1349 struct rt_prio_array *array = &rt_rq->active;
1350 struct list_head *queue = array->queue + rt_se_prio(rt_se);
1351
1352 if (head)
1353 list_move(&rt_se->run_list, queue);
1354 else
1355 list_move_tail(&rt_se->run_list, queue);
1356 }
1357}
1358
1359static void requeue_task_rt(struct rq *rq, struct task_struct *p, int head)
1360{
1361 struct sched_rt_entity *rt_se = &p->rt;
1362 struct rt_rq *rt_rq;
1363
1364 for_each_sched_rt_entity(rt_se) {
1365 rt_rq = rt_rq_of_se(rt_se);
1366 requeue_rt_entity(rt_rq, rt_se, head);
1367 }
1368}
1369
1370static void yield_task_rt(struct rq *rq)
1371{
1372 requeue_task_rt(rq, rq->curr, 0);
1373}
1374
1375#ifdef CONFIG_SMP
1376static int find_lowest_rq(struct task_struct *task);
1377
1378static int
1379select_task_rq_rt(struct task_struct *p, int cpu, int sd_flag, int flags)
1380{
1381 struct task_struct *curr;
1382 struct rq *rq;
1383
1384 /* For anything but wake ups, just return the task_cpu */
1385 if (sd_flag != SD_BALANCE_WAKE && sd_flag != SD_BALANCE_FORK)
1386 goto out;
1387
1388 rq = cpu_rq(cpu);
1389
1390 rcu_read_lock();
1391 curr = READ_ONCE(rq->curr); /* unlocked access */
1392
1393 /*
1394 * If the current task on @p's runqueue is an RT task, then
1395 * try to see if we can wake this RT task up on another
1396 * runqueue. Otherwise simply start this RT task
1397 * on its current runqueue.
1398 *
1399 * We want to avoid overloading runqueues. If the woken
1400 * task is a higher priority, then it will stay on this CPU
1401 * and the lower prio task should be moved to another CPU.
1402 * Even though this will probably make the lower prio task
1403 * lose its cache, we do not want to bounce a higher task
1404 * around just because it gave up its CPU, perhaps for a
1405 * lock?
1406 *
1407 * For equal prio tasks, we just let the scheduler sort it out.
1408 *
1409 * Otherwise, just let it ride on the affined RQ and the
1410 * post-schedule router will push the preempted task away
1411 *
1412 * This test is optimistic, if we get it wrong the load-balancer
1413 * will have to sort it out.
1414 */
1415 if (curr && unlikely(rt_task(curr)) &&
1416 (curr->nr_cpus_allowed < 2 ||
1417 curr->prio <= p->prio)) {
1418 int target = find_lowest_rq(p);
1419
1420 /*
1421 * Don't bother moving it if the destination CPU is
1422 * not running a lower priority task.
1423 */
1424 if (target != -1 &&
1425 p->prio < cpu_rq(target)->rt.highest_prio.curr)
1426 cpu = target;
1427 }
1428 rcu_read_unlock();
1429
1430out:
1431 return cpu;
1432}
1433
1434static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p)
1435{
1436 /*
1437 * Current can't be migrated, useless to reschedule,
1438 * let's hope p can move out.
1439 */
1440 if (rq->curr->nr_cpus_allowed == 1 ||
1441 !cpupri_find(&rq->rd->cpupri, rq->curr, NULL))
1442 return;
1443
1444 /*
1445 * p is migratable, so let's not schedule it and
1446 * see if it is pushed or pulled somewhere else.
1447 */
1448 if (p->nr_cpus_allowed != 1
1449 && cpupri_find(&rq->rd->cpupri, p, NULL))
1450 return;
1451
1452 /*
1453 * There appears to be other cpus that can accept
1454 * current and none to run 'p', so lets reschedule
1455 * to try and push current away:
1456 */
1457 requeue_task_rt(rq, p, 1);
1458 resched_curr(rq);
1459}
1460
1461#endif /* CONFIG_SMP */
1462
1463/*
1464 * Preempt the current task with a newly woken task if needed:
1465 */
1466static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p, int flags)
1467{
1468 if (p->prio < rq->curr->prio) {
1469 resched_curr(rq);
1470 return;
1471 }
1472
1473#ifdef CONFIG_SMP
1474 /*
1475 * If:
1476 *
1477 * - the newly woken task is of equal priority to the current task
1478 * - the newly woken task is non-migratable while current is migratable
1479 * - current will be preempted on the next reschedule
1480 *
1481 * we should check to see if current can readily move to a different
1482 * cpu. If so, we will reschedule to allow the push logic to try
1483 * to move current somewhere else, making room for our non-migratable
1484 * task.
1485 */
1486 if (p->prio == rq->curr->prio && !test_tsk_need_resched(rq->curr))
1487 check_preempt_equal_prio(rq, p);
1488#endif
1489}
1490
1491static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq,
1492 struct rt_rq *rt_rq)
1493{
1494 struct rt_prio_array *array = &rt_rq->active;
1495 struct sched_rt_entity *next = NULL;
1496 struct list_head *queue;
1497 int idx;
1498
1499 idx = sched_find_first_bit(array->bitmap);
1500 BUG_ON(idx >= MAX_RT_PRIO);
1501
1502 queue = array->queue + idx;
1503 next = list_entry(queue->next, struct sched_rt_entity, run_list);
1504
1505 return next;
1506}
1507
1508static struct task_struct *_pick_next_task_rt(struct rq *rq)
1509{
1510 struct sched_rt_entity *rt_se;
1511 struct task_struct *p;
1512 struct rt_rq *rt_rq = &rq->rt;
1513
1514 do {
1515 rt_se = pick_next_rt_entity(rq, rt_rq);
1516 BUG_ON(!rt_se);
1517 rt_rq = group_rt_rq(rt_se);
1518 } while (rt_rq);
1519
1520 p = rt_task_of(rt_se);
1521 p->se.exec_start = rq_clock_task(rq);
1522
1523 return p;
1524}
1525
1526static struct task_struct *
1527pick_next_task_rt(struct rq *rq, struct task_struct *prev)
1528{
1529 struct task_struct *p;
1530 struct rt_rq *rt_rq = &rq->rt;
1531
1532 if (need_pull_rt_task(rq, prev)) {
1533 /*
1534 * This is OK, because current is on_cpu, which avoids it being
1535 * picked for load-balance and preemption/IRQs are still
1536 * disabled avoiding further scheduler activity on it and we're
1537 * being very careful to re-start the picking loop.
1538 */
1539 lockdep_unpin_lock(&rq->lock);
1540 pull_rt_task(rq);
1541 lockdep_pin_lock(&rq->lock);
1542 /*
1543 * pull_rt_task() can drop (and re-acquire) rq->lock; this
1544 * means a dl or stop task can slip in, in which case we need
1545 * to re-start task selection.
1546 */
1547 if (unlikely((rq->stop && task_on_rq_queued(rq->stop)) ||
1548 rq->dl.dl_nr_running))
1549 return RETRY_TASK;
1550 }
1551
1552 /*
1553 * We may dequeue prev's rt_rq in put_prev_task().
1554 * So, we update time before rt_nr_running check.
1555 */
1556 if (prev->sched_class == &rt_sched_class)
1557 update_curr_rt(rq);
1558
1559 if (!rt_rq->rt_queued)
1560 return NULL;
1561
1562 put_prev_task(rq, prev);
1563
1564 p = _pick_next_task_rt(rq);
1565
1566 /* The running task is never eligible for pushing */
1567 dequeue_pushable_task(rq, p);
1568
1569 queue_push_tasks(rq);
1570
1571 return p;
1572}
1573
1574static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
1575{
1576 update_curr_rt(rq);
1577
1578 /*
1579 * The previous task needs to be made eligible for pushing
1580 * if it is still active
1581 */
1582 if (on_rt_rq(&p->rt) && p->nr_cpus_allowed > 1)
1583 enqueue_pushable_task(rq, p);
1584}
1585
1586#ifdef CONFIG_SMP
1587
1588/* Only try algorithms three times */
1589#define RT_MAX_TRIES 3
1590
1591static int pick_rt_task(struct rq *rq, struct task_struct *p, int cpu)
1592{
1593 if (!task_running(rq, p) &&
1594 cpumask_test_cpu(cpu, tsk_cpus_allowed(p)))
1595 return 1;
1596 return 0;
1597}
1598
1599/*
1600 * Return the highest pushable rq's task, which is suitable to be executed
1601 * on the cpu, NULL otherwise
1602 */
1603static struct task_struct *pick_highest_pushable_task(struct rq *rq, int cpu)
1604{
1605 struct plist_head *head = &rq->rt.pushable_tasks;
1606 struct task_struct *p;
1607
1608 if (!has_pushable_tasks(rq))
1609 return NULL;
1610
1611 plist_for_each_entry(p, head, pushable_tasks) {
1612 if (pick_rt_task(rq, p, cpu))
1613 return p;
1614 }
1615
1616 return NULL;
1617}
1618
1619static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask);
1620
1621static int find_lowest_rq(struct task_struct *task)
1622{
1623 struct sched_domain *sd;
1624 struct cpumask *lowest_mask = this_cpu_cpumask_var_ptr(local_cpu_mask);
1625 int this_cpu = smp_processor_id();
1626 int cpu = task_cpu(task);
1627
1628 /* Make sure the mask is initialized first */
1629 if (unlikely(!lowest_mask))
1630 return -1;
1631
1632 if (task->nr_cpus_allowed == 1)
1633 return -1; /* No other targets possible */
1634
1635 if (!cpupri_find(&task_rq(task)->rd->cpupri, task, lowest_mask))
1636 return -1; /* No targets found */
1637
1638 /*
1639 * At this point we have built a mask of cpus representing the
1640 * lowest priority tasks in the system. Now we want to elect
1641 * the best one based on our affinity and topology.
1642 *
1643 * We prioritize the last cpu that the task executed on since
1644 * it is most likely cache-hot in that location.
1645 */
1646 if (cpumask_test_cpu(cpu, lowest_mask))
1647 return cpu;
1648
1649 /*
1650 * Otherwise, we consult the sched_domains span maps to figure
1651 * out which cpu is logically closest to our hot cache data.
1652 */
1653 if (!cpumask_test_cpu(this_cpu, lowest_mask))
1654 this_cpu = -1; /* Skip this_cpu opt if not among lowest */
1655
1656 rcu_read_lock();
1657 for_each_domain(cpu, sd) {
1658 if (sd->flags & SD_WAKE_AFFINE) {
1659 int best_cpu;
1660
1661 /*
1662 * "this_cpu" is cheaper to preempt than a
1663 * remote processor.
1664 */
1665 if (this_cpu != -1 &&
1666 cpumask_test_cpu(this_cpu, sched_domain_span(sd))) {
1667 rcu_read_unlock();
1668 return this_cpu;
1669 }
1670
1671 best_cpu = cpumask_first_and(lowest_mask,
1672 sched_domain_span(sd));
1673 if (best_cpu < nr_cpu_ids) {
1674 rcu_read_unlock();
1675 return best_cpu;
1676 }
1677 }
1678 }
1679 rcu_read_unlock();
1680
1681 /*
1682 * And finally, if there were no matches within the domains
1683 * just give the caller *something* to work with from the compatible
1684 * locations.
1685 */
1686 if (this_cpu != -1)
1687 return this_cpu;
1688
1689 cpu = cpumask_any(lowest_mask);
1690 if (cpu < nr_cpu_ids)
1691 return cpu;
1692 return -1;
1693}
1694
1695/* Will lock the rq it finds */
1696static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq)
1697{
1698 struct rq *lowest_rq = NULL;
1699 int tries;
1700 int cpu;
1701
1702 for (tries = 0; tries < RT_MAX_TRIES; tries++) {
1703 cpu = find_lowest_rq(task);
1704
1705 if ((cpu == -1) || (cpu == rq->cpu))
1706 break;
1707
1708 lowest_rq = cpu_rq(cpu);
1709
1710 if (lowest_rq->rt.highest_prio.curr <= task->prio) {
1711 /*
1712 * Target rq has tasks of equal or higher priority,
1713 * retrying does not release any lock and is unlikely
1714 * to yield a different result.
1715 */
1716 lowest_rq = NULL;
1717 break;
1718 }
1719
1720 /* if the prio of this runqueue changed, try again */
1721 if (double_lock_balance(rq, lowest_rq)) {
1722 /*
1723 * We had to unlock the run queue. In
1724 * the mean time, task could have
1725 * migrated already or had its affinity changed.
1726 * Also make sure that it wasn't scheduled on its rq.
1727 */
1728 if (unlikely(task_rq(task) != rq ||
1729 !cpumask_test_cpu(lowest_rq->cpu,
1730 tsk_cpus_allowed(task)) ||
1731 task_running(rq, task) ||
1732 !rt_task(task) ||
1733 !task_on_rq_queued(task))) {
1734
1735 double_unlock_balance(rq, lowest_rq);
1736 lowest_rq = NULL;
1737 break;
1738 }
1739 }
1740
1741 /* If this rq is still suitable use it. */
1742 if (lowest_rq->rt.highest_prio.curr > task->prio)
1743 break;
1744
1745 /* try again */
1746 double_unlock_balance(rq, lowest_rq);
1747 lowest_rq = NULL;
1748 }
1749
1750 return lowest_rq;
1751}
1752
1753static struct task_struct *pick_next_pushable_task(struct rq *rq)
1754{
1755 struct task_struct *p;
1756
1757 if (!has_pushable_tasks(rq))
1758 return NULL;
1759
1760 p = plist_first_entry(&rq->rt.pushable_tasks,
1761 struct task_struct, pushable_tasks);
1762
1763 BUG_ON(rq->cpu != task_cpu(p));
1764 BUG_ON(task_current(rq, p));
1765 BUG_ON(p->nr_cpus_allowed <= 1);
1766
1767 BUG_ON(!task_on_rq_queued(p));
1768 BUG_ON(!rt_task(p));
1769
1770 return p;
1771}
1772
1773/*
1774 * If the current CPU has more than one RT task, see if the non
1775 * running task can migrate over to a CPU that is running a task
1776 * of lesser priority.
1777 */
1778static int push_rt_task(struct rq *rq)
1779{
1780 struct task_struct *next_task;
1781 struct rq *lowest_rq;
1782 int ret = 0;
1783
1784 if (!rq->rt.overloaded)
1785 return 0;
1786
1787 next_task = pick_next_pushable_task(rq);
1788 if (!next_task)
1789 return 0;
1790
1791retry:
1792 if (unlikely(next_task == rq->curr)) {
1793 WARN_ON(1);
1794 return 0;
1795 }
1796
1797 /*
1798 * It's possible that the next_task slipped in of
1799 * higher priority than current. If that's the case
1800 * just reschedule current.
1801 */
1802 if (unlikely(next_task->prio < rq->curr->prio)) {
1803 resched_curr(rq);
1804 return 0;
1805 }
1806
1807 /* We might release rq lock */
1808 get_task_struct(next_task);
1809
1810 /* find_lock_lowest_rq locks the rq if found */
1811 lowest_rq = find_lock_lowest_rq(next_task, rq);
1812 if (!lowest_rq) {
1813 struct task_struct *task;
1814 /*
1815 * find_lock_lowest_rq releases rq->lock
1816 * so it is possible that next_task has migrated.
1817 *
1818 * We need to make sure that the task is still on the same
1819 * run-queue and is also still the next task eligible for
1820 * pushing.
1821 */
1822 task = pick_next_pushable_task(rq);
1823 if (task_cpu(next_task) == rq->cpu && task == next_task) {
1824 /*
1825 * The task hasn't migrated, and is still the next
1826 * eligible task, but we failed to find a run-queue
1827 * to push it to. Do not retry in this case, since
1828 * other cpus will pull from us when ready.
1829 */
1830 goto out;
1831 }
1832
1833 if (!task)
1834 /* No more tasks, just exit */
1835 goto out;
1836
1837 /*
1838 * Something has shifted, try again.
1839 */
1840 put_task_struct(next_task);
1841 next_task = task;
1842 goto retry;
1843 }
1844
1845 deactivate_task(rq, next_task, 0);
1846 set_task_cpu(next_task, lowest_rq->cpu);
1847 activate_task(lowest_rq, next_task, 0);
1848 ret = 1;
1849
1850 resched_curr(lowest_rq);
1851
1852 double_unlock_balance(rq, lowest_rq);
1853
1854out:
1855 put_task_struct(next_task);
1856
1857 return ret;
1858}
1859
1860static void push_rt_tasks(struct rq *rq)
1861{
1862 /* push_rt_task will return true if it moved an RT */
1863 while (push_rt_task(rq))
1864 ;
1865}
1866
1867#ifdef HAVE_RT_PUSH_IPI
1868/*
1869 * The search for the next cpu always starts at rq->cpu and ends
1870 * when we reach rq->cpu again. It will never return rq->cpu.
1871 * This returns the next cpu to check, or nr_cpu_ids if the loop
1872 * is complete.
1873 *
1874 * rq->rt.push_cpu holds the last cpu returned by this function,
1875 * or if this is the first instance, it must hold rq->cpu.
1876 */
1877static int rto_next_cpu(struct rq *rq)
1878{
1879 int prev_cpu = rq->rt.push_cpu;
1880 int cpu;
1881
1882 cpu = cpumask_next(prev_cpu, rq->rd->rto_mask);
1883
1884 /*
1885 * If the previous cpu is less than the rq's CPU, then it already
1886 * passed the end of the mask, and has started from the beginning.
1887 * We end if the next CPU is greater or equal to rq's CPU.
1888 */
1889 if (prev_cpu < rq->cpu) {
1890 if (cpu >= rq->cpu)
1891 return nr_cpu_ids;
1892
1893 } else if (cpu >= nr_cpu_ids) {
1894 /*
1895 * We passed the end of the mask, start at the beginning.
1896 * If the result is greater or equal to the rq's CPU, then
1897 * the loop is finished.
1898 */
1899 cpu = cpumask_first(rq->rd->rto_mask);
1900 if (cpu >= rq->cpu)
1901 return nr_cpu_ids;
1902 }
1903 rq->rt.push_cpu = cpu;
1904
1905 /* Return cpu to let the caller know if the loop is finished or not */
1906 return cpu;
1907}
1908
1909static int find_next_push_cpu(struct rq *rq)
1910{
1911 struct rq *next_rq;
1912 int cpu;
1913
1914 while (1) {
1915 cpu = rto_next_cpu(rq);
1916 if (cpu >= nr_cpu_ids)
1917 break;
1918 next_rq = cpu_rq(cpu);
1919
1920 /* Make sure the next rq can push to this rq */
1921 if (next_rq->rt.highest_prio.next < rq->rt.highest_prio.curr)
1922 break;
1923 }
1924
1925 return cpu;
1926}
1927
1928#define RT_PUSH_IPI_EXECUTING 1
1929#define RT_PUSH_IPI_RESTART 2
1930
1931static void tell_cpu_to_push(struct rq *rq)
1932{
1933 int cpu;
1934
1935 if (rq->rt.push_flags & RT_PUSH_IPI_EXECUTING) {
1936 raw_spin_lock(&rq->rt.push_lock);
1937 /* Make sure it's still executing */
1938 if (rq->rt.push_flags & RT_PUSH_IPI_EXECUTING) {
1939 /*
1940 * Tell the IPI to restart the loop as things have
1941 * changed since it started.
1942 */
1943 rq->rt.push_flags |= RT_PUSH_IPI_RESTART;
1944 raw_spin_unlock(&rq->rt.push_lock);
1945 return;
1946 }
1947 raw_spin_unlock(&rq->rt.push_lock);
1948 }
1949
1950 /* When here, there's no IPI going around */
1951
1952 rq->rt.push_cpu = rq->cpu;
1953 cpu = find_next_push_cpu(rq);
1954 if (cpu >= nr_cpu_ids)
1955 return;
1956
1957 rq->rt.push_flags = RT_PUSH_IPI_EXECUTING;
1958
1959 irq_work_queue_on(&rq->rt.push_work, cpu);
1960}
1961
1962/* Called from hardirq context */
1963static void try_to_push_tasks(void *arg)
1964{
1965 struct rt_rq *rt_rq = arg;
1966 struct rq *rq, *src_rq;
1967 int this_cpu;
1968 int cpu;
1969
1970 this_cpu = rt_rq->push_cpu;
1971
1972 /* Paranoid check */
1973 BUG_ON(this_cpu != smp_processor_id());
1974
1975 rq = cpu_rq(this_cpu);
1976 src_rq = rq_of_rt_rq(rt_rq);
1977
1978again:
1979 if (has_pushable_tasks(rq)) {
1980 raw_spin_lock(&rq->lock);
1981 push_rt_task(rq);
1982 raw_spin_unlock(&rq->lock);
1983 }
1984
1985 /* Pass the IPI to the next rt overloaded queue */
1986 raw_spin_lock(&rt_rq->push_lock);
1987 /*
1988 * If the source queue changed since the IPI went out,
1989 * we need to restart the search from that CPU again.
1990 */
1991 if (rt_rq->push_flags & RT_PUSH_IPI_RESTART) {
1992 rt_rq->push_flags &= ~RT_PUSH_IPI_RESTART;
1993 rt_rq->push_cpu = src_rq->cpu;
1994 }
1995
1996 cpu = find_next_push_cpu(src_rq);
1997
1998 if (cpu >= nr_cpu_ids)
1999 rt_rq->push_flags &= ~RT_PUSH_IPI_EXECUTING;
2000 raw_spin_unlock(&rt_rq->push_lock);
2001
2002 if (cpu >= nr_cpu_ids)
2003 return;
2004
2005 /*
2006 * It is possible that a restart caused this CPU to be
2007 * chosen again. Don't bother with an IPI, just see if we
2008 * have more to push.
2009 */
2010 if (unlikely(cpu == rq->cpu))
2011 goto again;
2012
2013 /* Try the next RT overloaded CPU */
2014 irq_work_queue_on(&rt_rq->push_work, cpu);
2015}
2016
2017static void push_irq_work_func(struct irq_work *work)
2018{
2019 struct rt_rq *rt_rq = container_of(work, struct rt_rq, push_work);
2020
2021 try_to_push_tasks(rt_rq);
2022}
2023#endif /* HAVE_RT_PUSH_IPI */
2024
2025static void pull_rt_task(struct rq *this_rq)
2026{
2027 int this_cpu = this_rq->cpu, cpu;
2028 bool resched = false;
2029 struct task_struct *p;
2030 struct rq *src_rq;
2031
2032 if (likely(!rt_overloaded(this_rq)))
2033 return;
2034
2035 /*
2036 * Match the barrier from rt_set_overloaded; this guarantees that if we
2037 * see overloaded we must also see the rto_mask bit.
2038 */
2039 smp_rmb();
2040
2041#ifdef HAVE_RT_PUSH_IPI
2042 if (sched_feat(RT_PUSH_IPI)) {
2043 tell_cpu_to_push(this_rq);
2044 return;
2045 }
2046#endif
2047
2048 for_each_cpu(cpu, this_rq->rd->rto_mask) {
2049 if (this_cpu == cpu)
2050 continue;
2051
2052 src_rq = cpu_rq(cpu);
2053
2054 /*
2055 * Don't bother taking the src_rq->lock if the next highest
2056 * task is known to be lower-priority than our current task.
2057 * This may look racy, but if this value is about to go
2058 * logically higher, the src_rq will push this task away.
2059 * And if its going logically lower, we do not care
2060 */
2061 if (src_rq->rt.highest_prio.next >=
2062 this_rq->rt.highest_prio.curr)
2063 continue;
2064
2065 /*
2066 * We can potentially drop this_rq's lock in
2067 * double_lock_balance, and another CPU could
2068 * alter this_rq
2069 */
2070 double_lock_balance(this_rq, src_rq);
2071
2072 /*
2073 * We can pull only a task, which is pushable
2074 * on its rq, and no others.
2075 */
2076 p = pick_highest_pushable_task(src_rq, this_cpu);
2077
2078 /*
2079 * Do we have an RT task that preempts
2080 * the to-be-scheduled task?
2081 */
2082 if (p && (p->prio < this_rq->rt.highest_prio.curr)) {
2083 WARN_ON(p == src_rq->curr);
2084 WARN_ON(!task_on_rq_queued(p));
2085
2086 /*
2087 * There's a chance that p is higher in priority
2088 * than what's currently running on its cpu.
2089 * This is just that p is wakeing up and hasn't
2090 * had a chance to schedule. We only pull
2091 * p if it is lower in priority than the
2092 * current task on the run queue
2093 */
2094 if (p->prio < src_rq->curr->prio)
2095 goto skip;
2096
2097 resched = true;
2098
2099 deactivate_task(src_rq, p, 0);
2100 set_task_cpu(p, this_cpu);
2101 activate_task(this_rq, p, 0);
2102 /*
2103 * We continue with the search, just in
2104 * case there's an even higher prio task
2105 * in another runqueue. (low likelihood
2106 * but possible)
2107 */
2108 }
2109skip:
2110 double_unlock_balance(this_rq, src_rq);
2111 }
2112
2113 if (resched)
2114 resched_curr(this_rq);
2115}
2116
2117/*
2118 * If we are not running and we are not going to reschedule soon, we should
2119 * try to push tasks away now
2120 */
2121static void task_woken_rt(struct rq *rq, struct task_struct *p)
2122{
2123 if (!task_running(rq, p) &&
2124 !test_tsk_need_resched(rq->curr) &&
2125 p->nr_cpus_allowed > 1 &&
2126 (dl_task(rq->curr) || rt_task(rq->curr)) &&
2127 (rq->curr->nr_cpus_allowed < 2 ||
2128 rq->curr->prio <= p->prio))
2129 push_rt_tasks(rq);
2130}
2131
2132/* Assumes rq->lock is held */
2133static void rq_online_rt(struct rq *rq)
2134{
2135 if (rq->rt.overloaded)
2136 rt_set_overload(rq);
2137
2138 __enable_runtime(rq);
2139
2140 cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio.curr);
2141}
2142
2143/* Assumes rq->lock is held */
2144static void rq_offline_rt(struct rq *rq)
2145{
2146 if (rq->rt.overloaded)
2147 rt_clear_overload(rq);
2148
2149 __disable_runtime(rq);
2150
2151 cpupri_set(&rq->rd->cpupri, rq->cpu, CPUPRI_INVALID);
2152}
2153
2154/*
2155 * When switch from the rt queue, we bring ourselves to a position
2156 * that we might want to pull RT tasks from other runqueues.
2157 */
2158static void switched_from_rt(struct rq *rq, struct task_struct *p)
2159{
2160 /*
2161 * If there are other RT tasks then we will reschedule
2162 * and the scheduling of the other RT tasks will handle
2163 * the balancing. But if we are the last RT task
2164 * we may need to handle the pulling of RT tasks
2165 * now.
2166 */
2167 if (!task_on_rq_queued(p) || rq->rt.rt_nr_running)
2168 return;
2169
2170 queue_pull_task(rq);
2171}
2172
2173void __init init_sched_rt_class(void)
2174{
2175 unsigned int i;
2176
2177 for_each_possible_cpu(i) {
2178 zalloc_cpumask_var_node(&per_cpu(local_cpu_mask, i),
2179 GFP_KERNEL, cpu_to_node(i));
2180 }
2181}
2182#endif /* CONFIG_SMP */
2183
2184/*
2185 * When switching a task to RT, we may overload the runqueue
2186 * with RT tasks. In this case we try to push them off to
2187 * other runqueues.
2188 */
2189static void switched_to_rt(struct rq *rq, struct task_struct *p)
2190{
2191 /*
2192 * If we are already running, then there's nothing
2193 * that needs to be done. But if we are not running
2194 * we may need to preempt the current running task.
2195 * If that current running task is also an RT task
2196 * then see if we can move to another run queue.
2197 */
2198 if (task_on_rq_queued(p) && rq->curr != p) {
2199#ifdef CONFIG_SMP
2200 if (p->nr_cpus_allowed > 1 && rq->rt.overloaded)
2201 queue_push_tasks(rq);
2202#else
2203 if (p->prio < rq->curr->prio)
2204 resched_curr(rq);
2205#endif /* CONFIG_SMP */
2206 }
2207}
2208
2209/*
2210 * Priority of the task has changed. This may cause
2211 * us to initiate a push or pull.
2212 */
2213static void
2214prio_changed_rt(struct rq *rq, struct task_struct *p, int oldprio)
2215{
2216 if (!task_on_rq_queued(p))
2217 return;
2218
2219 if (rq->curr == p) {
2220#ifdef CONFIG_SMP
2221 /*
2222 * If our priority decreases while running, we
2223 * may need to pull tasks to this runqueue.
2224 */
2225 if (oldprio < p->prio)
2226 queue_pull_task(rq);
2227
2228 /*
2229 * If there's a higher priority task waiting to run
2230 * then reschedule.
2231 */
2232 if (p->prio > rq->rt.highest_prio.curr)
2233 resched_curr(rq);
2234#else
2235 /* For UP simply resched on drop of prio */
2236 if (oldprio < p->prio)
2237 resched_curr(rq);
2238#endif /* CONFIG_SMP */
2239 } else {
2240 /*
2241 * This task is not running, but if it is
2242 * greater than the current running task
2243 * then reschedule.
2244 */
2245 if (p->prio < rq->curr->prio)
2246 resched_curr(rq);
2247 }
2248}
2249
2250static void watchdog(struct rq *rq, struct task_struct *p)
2251{
2252 unsigned long soft, hard;
2253
2254 /* max may change after cur was read, this will be fixed next tick */
2255 soft = task_rlimit(p, RLIMIT_RTTIME);
2256 hard = task_rlimit_max(p, RLIMIT_RTTIME);
2257
2258 if (soft != RLIM_INFINITY) {
2259 unsigned long next;
2260
2261 if (p->rt.watchdog_stamp != jiffies) {
2262 p->rt.timeout++;
2263 p->rt.watchdog_stamp = jiffies;
2264 }
2265
2266 next = DIV_ROUND_UP(min(soft, hard), USEC_PER_SEC/HZ);
2267 if (p->rt.timeout > next)
2268 p->cputime_expires.sched_exp = p->se.sum_exec_runtime;
2269 }
2270}
2271
2272static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued)
2273{
2274 struct sched_rt_entity *rt_se = &p->rt;
2275
2276 update_curr_rt(rq);
2277
2278 watchdog(rq, p);
2279
2280 /*
2281 * RR tasks need a special form of timeslice management.
2282 * FIFO tasks have no timeslices.
2283 */
2284 if (p->policy != SCHED_RR)
2285 return;
2286
2287 if (--p->rt.time_slice)
2288 return;
2289
2290 p->rt.time_slice = sched_rr_timeslice;
2291
2292 /*
2293 * Requeue to the end of queue if we (and all of our ancestors) are not
2294 * the only element on the queue
2295 */
2296 for_each_sched_rt_entity(rt_se) {
2297 if (rt_se->run_list.prev != rt_se->run_list.next) {
2298 requeue_task_rt(rq, p, 0);
2299 resched_curr(rq);
2300 return;
2301 }
2302 }
2303}
2304
2305static void set_curr_task_rt(struct rq *rq)
2306{
2307 struct task_struct *p = rq->curr;
2308
2309 p->se.exec_start = rq_clock_task(rq);
2310
2311 /* The running task is never eligible for pushing */
2312 dequeue_pushable_task(rq, p);
2313}
2314
2315static unsigned int get_rr_interval_rt(struct rq *rq, struct task_struct *task)
2316{
2317 /*
2318 * Time slice is 0 for SCHED_FIFO tasks
2319 */
2320 if (task->policy == SCHED_RR)
2321 return sched_rr_timeslice;
2322 else
2323 return 0;
2324}
2325
2326const struct sched_class rt_sched_class = {
2327 .next = &fair_sched_class,
2328 .enqueue_task = enqueue_task_rt,
2329 .dequeue_task = dequeue_task_rt,
2330 .yield_task = yield_task_rt,
2331
2332 .check_preempt_curr = check_preempt_curr_rt,
2333
2334 .pick_next_task = pick_next_task_rt,
2335 .put_prev_task = put_prev_task_rt,
2336
2337#ifdef CONFIG_SMP
2338 .select_task_rq = select_task_rq_rt,
2339
2340 .set_cpus_allowed = set_cpus_allowed_common,
2341 .rq_online = rq_online_rt,
2342 .rq_offline = rq_offline_rt,
2343 .task_woken = task_woken_rt,
2344 .switched_from = switched_from_rt,
2345#endif
2346
2347 .set_curr_task = set_curr_task_rt,
2348 .task_tick = task_tick_rt,
2349
2350 .get_rr_interval = get_rr_interval_rt,
2351
2352 .prio_changed = prio_changed_rt,
2353 .switched_to = switched_to_rt,
2354
2355 .update_curr = update_curr_rt,
2356};
2357
2358#ifdef CONFIG_SCHED_DEBUG
2359extern void print_rt_rq(struct seq_file *m, int cpu, struct rt_rq *rt_rq);
2360
2361void print_rt_stats(struct seq_file *m, int cpu)
2362{
2363 rt_rq_iter_t iter;
2364 struct rt_rq *rt_rq;
2365
2366 rcu_read_lock();
2367 for_each_rt_rq(rt_rq, iter, cpu_rq(cpu))
2368 print_rt_rq(m, cpu, rt_rq);
2369 rcu_read_unlock();
2370}
2371#endif /* CONFIG_SCHED_DEBUG */