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1/*
2 * CPUFreq governor based on scheduler-provided CPU utilization data.
3 *
4 * Copyright (C) 2016, Intel Corporation
5 * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 */
11
12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14#include "sched.h"
15
16#include <trace/events/power.h>
17
18struct sugov_tunables {
19 struct gov_attr_set attr_set;
20 unsigned int rate_limit_us;
21};
22
23struct sugov_policy {
24 struct cpufreq_policy *policy;
25
26 struct sugov_tunables *tunables;
27 struct list_head tunables_hook;
28
29 raw_spinlock_t update_lock; /* For shared policies */
30 u64 last_freq_update_time;
31 s64 freq_update_delay_ns;
32 unsigned int next_freq;
33 unsigned int cached_raw_freq;
34
35 /* The next fields are only needed if fast switch cannot be used: */
36 struct irq_work irq_work;
37 struct kthread_work work;
38 struct mutex work_lock;
39 struct kthread_worker worker;
40 struct task_struct *thread;
41 bool work_in_progress;
42
43 bool need_freq_update;
44};
45
46struct sugov_cpu {
47 struct update_util_data update_util;
48 struct sugov_policy *sg_policy;
49 unsigned int cpu;
50
51 bool iowait_boost_pending;
52 unsigned int iowait_boost;
53 unsigned int iowait_boost_max;
54 u64 last_update;
55
56 /* The fields below are only needed when sharing a policy: */
57 unsigned long util_cfs;
58 unsigned long util_dl;
59 unsigned long max;
60
61 /* The field below is for single-CPU policies only: */
62#ifdef CONFIG_NO_HZ_COMMON
63 unsigned long saved_idle_calls;
64#endif
65};
66
67static DEFINE_PER_CPU(struct sugov_cpu, sugov_cpu);
68
69/************************ Governor internals ***********************/
70
71static bool sugov_should_update_freq(struct sugov_policy *sg_policy, u64 time)
72{
73 s64 delta_ns;
74
75 /*
76 * Since cpufreq_update_util() is called with rq->lock held for
77 * the @target_cpu, our per-CPU data is fully serialized.
78 *
79 * However, drivers cannot in general deal with cross-CPU
80 * requests, so while get_next_freq() will work, our
81 * sugov_update_commit() call may not for the fast switching platforms.
82 *
83 * Hence stop here for remote requests if they aren't supported
84 * by the hardware, as calculating the frequency is pointless if
85 * we cannot in fact act on it.
86 *
87 * For the slow switching platforms, the kthread is always scheduled on
88 * the right set of CPUs and any CPU can find the next frequency and
89 * schedule the kthread.
90 */
91 if (sg_policy->policy->fast_switch_enabled &&
92 !cpufreq_can_do_remote_dvfs(sg_policy->policy))
93 return false;
94
95 if (sg_policy->work_in_progress)
96 return false;
97
98 if (unlikely(sg_policy->need_freq_update)) {
99 sg_policy->need_freq_update = false;
100 /*
101 * This happens when limits change, so forget the previous
102 * next_freq value and force an update.
103 */
104 sg_policy->next_freq = UINT_MAX;
105 return true;
106 }
107
108 delta_ns = time - sg_policy->last_freq_update_time;
109
110 return delta_ns >= sg_policy->freq_update_delay_ns;
111}
112
113static void sugov_update_commit(struct sugov_policy *sg_policy, u64 time,
114 unsigned int next_freq)
115{
116 struct cpufreq_policy *policy = sg_policy->policy;
117
118 if (sg_policy->next_freq == next_freq)
119 return;
120
121 sg_policy->next_freq = next_freq;
122 sg_policy->last_freq_update_time = time;
123
124 if (policy->fast_switch_enabled) {
125 next_freq = cpufreq_driver_fast_switch(policy, next_freq);
126 if (!next_freq)
127 return;
128
129 policy->cur = next_freq;
130 trace_cpu_frequency(next_freq, smp_processor_id());
131 } else {
132 sg_policy->work_in_progress = true;
133 irq_work_queue(&sg_policy->irq_work);
134 }
135}
136
137/**
138 * get_next_freq - Compute a new frequency for a given cpufreq policy.
139 * @sg_policy: schedutil policy object to compute the new frequency for.
140 * @util: Current CPU utilization.
141 * @max: CPU capacity.
142 *
143 * If the utilization is frequency-invariant, choose the new frequency to be
144 * proportional to it, that is
145 *
146 * next_freq = C * max_freq * util / max
147 *
148 * Otherwise, approximate the would-be frequency-invariant utilization by
149 * util_raw * (curr_freq / max_freq) which leads to
150 *
151 * next_freq = C * curr_freq * util_raw / max
152 *
153 * Take C = 1.25 for the frequency tipping point at (util / max) = 0.8.
154 *
155 * The lowest driver-supported frequency which is equal or greater than the raw
156 * next_freq (as calculated above) is returned, subject to policy min/max and
157 * cpufreq driver limitations.
158 */
159static unsigned int get_next_freq(struct sugov_policy *sg_policy,
160 unsigned long util, unsigned long max)
161{
162 struct cpufreq_policy *policy = sg_policy->policy;
163 unsigned int freq = arch_scale_freq_invariant() ?
164 policy->cpuinfo.max_freq : policy->cur;
165
166 freq = (freq + (freq >> 2)) * util / max;
167
168 if (freq == sg_policy->cached_raw_freq && sg_policy->next_freq != UINT_MAX)
169 return sg_policy->next_freq;
170 sg_policy->cached_raw_freq = freq;
171 return cpufreq_driver_resolve_freq(policy, freq);
172}
173
174static void sugov_get_util(struct sugov_cpu *sg_cpu)
175{
176 struct rq *rq = cpu_rq(sg_cpu->cpu);
177
178 sg_cpu->max = arch_scale_cpu_capacity(NULL, sg_cpu->cpu);
179 sg_cpu->util_cfs = cpu_util_cfs(rq);
180 sg_cpu->util_dl = cpu_util_dl(rq);
181}
182
183static unsigned long sugov_aggregate_util(struct sugov_cpu *sg_cpu)
184{
185 struct rq *rq = cpu_rq(sg_cpu->cpu);
186 unsigned long util;
187
188 if (rq->rt.rt_nr_running) {
189 util = sg_cpu->max;
190 } else {
191 util = sg_cpu->util_dl;
192 if (rq->cfs.h_nr_running)
193 util += sg_cpu->util_cfs;
194 }
195
196 /*
197 * Ideally we would like to set util_dl as min/guaranteed freq and
198 * util_cfs + util_dl as requested freq. However, cpufreq is not yet
199 * ready for such an interface. So, we only do the latter for now.
200 */
201 return min(util, sg_cpu->max);
202}
203
204static void sugov_set_iowait_boost(struct sugov_cpu *sg_cpu, u64 time, unsigned int flags)
205{
206 if (flags & SCHED_CPUFREQ_IOWAIT) {
207 if (sg_cpu->iowait_boost_pending)
208 return;
209
210 sg_cpu->iowait_boost_pending = true;
211
212 if (sg_cpu->iowait_boost) {
213 sg_cpu->iowait_boost <<= 1;
214 if (sg_cpu->iowait_boost > sg_cpu->iowait_boost_max)
215 sg_cpu->iowait_boost = sg_cpu->iowait_boost_max;
216 } else {
217 sg_cpu->iowait_boost = sg_cpu->sg_policy->policy->min;
218 }
219 } else if (sg_cpu->iowait_boost) {
220 s64 delta_ns = time - sg_cpu->last_update;
221
222 /* Clear iowait_boost if the CPU apprears to have been idle. */
223 if (delta_ns > TICK_NSEC) {
224 sg_cpu->iowait_boost = 0;
225 sg_cpu->iowait_boost_pending = false;
226 }
227 }
228}
229
230static void sugov_iowait_boost(struct sugov_cpu *sg_cpu, unsigned long *util,
231 unsigned long *max)
232{
233 unsigned int boost_util, boost_max;
234
235 if (!sg_cpu->iowait_boost)
236 return;
237
238 if (sg_cpu->iowait_boost_pending) {
239 sg_cpu->iowait_boost_pending = false;
240 } else {
241 sg_cpu->iowait_boost >>= 1;
242 if (sg_cpu->iowait_boost < sg_cpu->sg_policy->policy->min) {
243 sg_cpu->iowait_boost = 0;
244 return;
245 }
246 }
247
248 boost_util = sg_cpu->iowait_boost;
249 boost_max = sg_cpu->iowait_boost_max;
250
251 if (*util * boost_max < *max * boost_util) {
252 *util = boost_util;
253 *max = boost_max;
254 }
255}
256
257#ifdef CONFIG_NO_HZ_COMMON
258static bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu)
259{
260 unsigned long idle_calls = tick_nohz_get_idle_calls_cpu(sg_cpu->cpu);
261 bool ret = idle_calls == sg_cpu->saved_idle_calls;
262
263 sg_cpu->saved_idle_calls = idle_calls;
264 return ret;
265}
266#else
267static inline bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu) { return false; }
268#endif /* CONFIG_NO_HZ_COMMON */
269
270/*
271 * Make sugov_should_update_freq() ignore the rate limit when DL
272 * has increased the utilization.
273 */
274static inline void ignore_dl_rate_limit(struct sugov_cpu *sg_cpu, struct sugov_policy *sg_policy)
275{
276 if (cpu_util_dl(cpu_rq(sg_cpu->cpu)) > sg_cpu->util_dl)
277 sg_policy->need_freq_update = true;
278}
279
280static void sugov_update_single(struct update_util_data *hook, u64 time,
281 unsigned int flags)
282{
283 struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
284 struct sugov_policy *sg_policy = sg_cpu->sg_policy;
285 unsigned long util, max;
286 unsigned int next_f;
287 bool busy;
288
289 sugov_set_iowait_boost(sg_cpu, time, flags);
290 sg_cpu->last_update = time;
291
292 ignore_dl_rate_limit(sg_cpu, sg_policy);
293
294 if (!sugov_should_update_freq(sg_policy, time))
295 return;
296
297 busy = sugov_cpu_is_busy(sg_cpu);
298
299 sugov_get_util(sg_cpu);
300 max = sg_cpu->max;
301 util = sugov_aggregate_util(sg_cpu);
302 sugov_iowait_boost(sg_cpu, &util, &max);
303 next_f = get_next_freq(sg_policy, util, max);
304 /*
305 * Do not reduce the frequency if the CPU has not been idle
306 * recently, as the reduction is likely to be premature then.
307 */
308 if (busy && next_f < sg_policy->next_freq &&
309 sg_policy->next_freq != UINT_MAX) {
310 next_f = sg_policy->next_freq;
311
312 /* Reset cached freq as next_freq has changed */
313 sg_policy->cached_raw_freq = 0;
314 }
315
316 sugov_update_commit(sg_policy, time, next_f);
317}
318
319static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu, u64 time)
320{
321 struct sugov_policy *sg_policy = sg_cpu->sg_policy;
322 struct cpufreq_policy *policy = sg_policy->policy;
323 unsigned long util = 0, max = 1;
324 unsigned int j;
325
326 for_each_cpu(j, policy->cpus) {
327 struct sugov_cpu *j_sg_cpu = &per_cpu(sugov_cpu, j);
328 unsigned long j_util, j_max;
329 s64 delta_ns;
330
331 sugov_get_util(j_sg_cpu);
332
333 /*
334 * If the CFS CPU utilization was last updated before the
335 * previous frequency update and the time elapsed between the
336 * last update of the CPU utilization and the last frequency
337 * update is long enough, reset iowait_boost and util_cfs, as
338 * they are now probably stale. However, still consider the
339 * CPU contribution if it has some DEADLINE utilization
340 * (util_dl).
341 */
342 delta_ns = time - j_sg_cpu->last_update;
343 if (delta_ns > TICK_NSEC) {
344 j_sg_cpu->iowait_boost = 0;
345 j_sg_cpu->iowait_boost_pending = false;
346 }
347
348 j_max = j_sg_cpu->max;
349 j_util = sugov_aggregate_util(j_sg_cpu);
350 sugov_iowait_boost(j_sg_cpu, &j_util, &j_max);
351 if (j_util * max > j_max * util) {
352 util = j_util;
353 max = j_max;
354 }
355 }
356
357 return get_next_freq(sg_policy, util, max);
358}
359
360static void
361sugov_update_shared(struct update_util_data *hook, u64 time, unsigned int flags)
362{
363 struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
364 struct sugov_policy *sg_policy = sg_cpu->sg_policy;
365 unsigned int next_f;
366
367 raw_spin_lock(&sg_policy->update_lock);
368
369 sugov_set_iowait_boost(sg_cpu, time, flags);
370 sg_cpu->last_update = time;
371
372 ignore_dl_rate_limit(sg_cpu, sg_policy);
373
374 if (sugov_should_update_freq(sg_policy, time)) {
375 next_f = sugov_next_freq_shared(sg_cpu, time);
376 sugov_update_commit(sg_policy, time, next_f);
377 }
378
379 raw_spin_unlock(&sg_policy->update_lock);
380}
381
382static void sugov_work(struct kthread_work *work)
383{
384 struct sugov_policy *sg_policy = container_of(work, struct sugov_policy, work);
385
386 mutex_lock(&sg_policy->work_lock);
387 __cpufreq_driver_target(sg_policy->policy, sg_policy->next_freq,
388 CPUFREQ_RELATION_L);
389 mutex_unlock(&sg_policy->work_lock);
390
391 sg_policy->work_in_progress = false;
392}
393
394static void sugov_irq_work(struct irq_work *irq_work)
395{
396 struct sugov_policy *sg_policy;
397
398 sg_policy = container_of(irq_work, struct sugov_policy, irq_work);
399
400 kthread_queue_work(&sg_policy->worker, &sg_policy->work);
401}
402
403/************************** sysfs interface ************************/
404
405static struct sugov_tunables *global_tunables;
406static DEFINE_MUTEX(global_tunables_lock);
407
408static inline struct sugov_tunables *to_sugov_tunables(struct gov_attr_set *attr_set)
409{
410 return container_of(attr_set, struct sugov_tunables, attr_set);
411}
412
413static ssize_t rate_limit_us_show(struct gov_attr_set *attr_set, char *buf)
414{
415 struct sugov_tunables *tunables = to_sugov_tunables(attr_set);
416
417 return sprintf(buf, "%u\n", tunables->rate_limit_us);
418}
419
420static ssize_t
421rate_limit_us_store(struct gov_attr_set *attr_set, const char *buf, size_t count)
422{
423 struct sugov_tunables *tunables = to_sugov_tunables(attr_set);
424 struct sugov_policy *sg_policy;
425 unsigned int rate_limit_us;
426
427 if (kstrtouint(buf, 10, &rate_limit_us))
428 return -EINVAL;
429
430 tunables->rate_limit_us = rate_limit_us;
431
432 list_for_each_entry(sg_policy, &attr_set->policy_list, tunables_hook)
433 sg_policy->freq_update_delay_ns = rate_limit_us * NSEC_PER_USEC;
434
435 return count;
436}
437
438static struct governor_attr rate_limit_us = __ATTR_RW(rate_limit_us);
439
440static struct attribute *sugov_attributes[] = {
441 &rate_limit_us.attr,
442 NULL
443};
444
445static struct kobj_type sugov_tunables_ktype = {
446 .default_attrs = sugov_attributes,
447 .sysfs_ops = &governor_sysfs_ops,
448};
449
450/********************** cpufreq governor interface *********************/
451
452static struct cpufreq_governor schedutil_gov;
453
454static struct sugov_policy *sugov_policy_alloc(struct cpufreq_policy *policy)
455{
456 struct sugov_policy *sg_policy;
457
458 sg_policy = kzalloc(sizeof(*sg_policy), GFP_KERNEL);
459 if (!sg_policy)
460 return NULL;
461
462 sg_policy->policy = policy;
463 raw_spin_lock_init(&sg_policy->update_lock);
464 return sg_policy;
465}
466
467static void sugov_policy_free(struct sugov_policy *sg_policy)
468{
469 kfree(sg_policy);
470}
471
472static int sugov_kthread_create(struct sugov_policy *sg_policy)
473{
474 struct task_struct *thread;
475 struct sched_attr attr = {
476 .size = sizeof(struct sched_attr),
477 .sched_policy = SCHED_DEADLINE,
478 .sched_flags = SCHED_FLAG_SUGOV,
479 .sched_nice = 0,
480 .sched_priority = 0,
481 /*
482 * Fake (unused) bandwidth; workaround to "fix"
483 * priority inheritance.
484 */
485 .sched_runtime = 1000000,
486 .sched_deadline = 10000000,
487 .sched_period = 10000000,
488 };
489 struct cpufreq_policy *policy = sg_policy->policy;
490 int ret;
491
492 /* kthread only required for slow path */
493 if (policy->fast_switch_enabled)
494 return 0;
495
496 kthread_init_work(&sg_policy->work, sugov_work);
497 kthread_init_worker(&sg_policy->worker);
498 thread = kthread_create(kthread_worker_fn, &sg_policy->worker,
499 "sugov:%d",
500 cpumask_first(policy->related_cpus));
501 if (IS_ERR(thread)) {
502 pr_err("failed to create sugov thread: %ld\n", PTR_ERR(thread));
503 return PTR_ERR(thread);
504 }
505
506 ret = sched_setattr_nocheck(thread, &attr);
507 if (ret) {
508 kthread_stop(thread);
509 pr_warn("%s: failed to set SCHED_DEADLINE\n", __func__);
510 return ret;
511 }
512
513 sg_policy->thread = thread;
514
515 /* Kthread is bound to all CPUs by default */
516 if (!policy->dvfs_possible_from_any_cpu)
517 kthread_bind_mask(thread, policy->related_cpus);
518
519 init_irq_work(&sg_policy->irq_work, sugov_irq_work);
520 mutex_init(&sg_policy->work_lock);
521
522 wake_up_process(thread);
523
524 return 0;
525}
526
527static void sugov_kthread_stop(struct sugov_policy *sg_policy)
528{
529 /* kthread only required for slow path */
530 if (sg_policy->policy->fast_switch_enabled)
531 return;
532
533 kthread_flush_worker(&sg_policy->worker);
534 kthread_stop(sg_policy->thread);
535 mutex_destroy(&sg_policy->work_lock);
536}
537
538static struct sugov_tunables *sugov_tunables_alloc(struct sugov_policy *sg_policy)
539{
540 struct sugov_tunables *tunables;
541
542 tunables = kzalloc(sizeof(*tunables), GFP_KERNEL);
543 if (tunables) {
544 gov_attr_set_init(&tunables->attr_set, &sg_policy->tunables_hook);
545 if (!have_governor_per_policy())
546 global_tunables = tunables;
547 }
548 return tunables;
549}
550
551static void sugov_tunables_free(struct sugov_tunables *tunables)
552{
553 if (!have_governor_per_policy())
554 global_tunables = NULL;
555
556 kfree(tunables);
557}
558
559static int sugov_init(struct cpufreq_policy *policy)
560{
561 struct sugov_policy *sg_policy;
562 struct sugov_tunables *tunables;
563 int ret = 0;
564
565 /* State should be equivalent to EXIT */
566 if (policy->governor_data)
567 return -EBUSY;
568
569 cpufreq_enable_fast_switch(policy);
570
571 sg_policy = sugov_policy_alloc(policy);
572 if (!sg_policy) {
573 ret = -ENOMEM;
574 goto disable_fast_switch;
575 }
576
577 ret = sugov_kthread_create(sg_policy);
578 if (ret)
579 goto free_sg_policy;
580
581 mutex_lock(&global_tunables_lock);
582
583 if (global_tunables) {
584 if (WARN_ON(have_governor_per_policy())) {
585 ret = -EINVAL;
586 goto stop_kthread;
587 }
588 policy->governor_data = sg_policy;
589 sg_policy->tunables = global_tunables;
590
591 gov_attr_set_get(&global_tunables->attr_set, &sg_policy->tunables_hook);
592 goto out;
593 }
594
595 tunables = sugov_tunables_alloc(sg_policy);
596 if (!tunables) {
597 ret = -ENOMEM;
598 goto stop_kthread;
599 }
600
601 tunables->rate_limit_us = cpufreq_policy_transition_delay_us(policy);
602
603 policy->governor_data = sg_policy;
604 sg_policy->tunables = tunables;
605
606 ret = kobject_init_and_add(&tunables->attr_set.kobj, &sugov_tunables_ktype,
607 get_governor_parent_kobj(policy), "%s",
608 schedutil_gov.name);
609 if (ret)
610 goto fail;
611
612out:
613 mutex_unlock(&global_tunables_lock);
614 return 0;
615
616fail:
617 policy->governor_data = NULL;
618 sugov_tunables_free(tunables);
619
620stop_kthread:
621 sugov_kthread_stop(sg_policy);
622 mutex_unlock(&global_tunables_lock);
623
624free_sg_policy:
625 sugov_policy_free(sg_policy);
626
627disable_fast_switch:
628 cpufreq_disable_fast_switch(policy);
629
630 pr_err("initialization failed (error %d)\n", ret);
631 return ret;
632}
633
634static void sugov_exit(struct cpufreq_policy *policy)
635{
636 struct sugov_policy *sg_policy = policy->governor_data;
637 struct sugov_tunables *tunables = sg_policy->tunables;
638 unsigned int count;
639
640 mutex_lock(&global_tunables_lock);
641
642 count = gov_attr_set_put(&tunables->attr_set, &sg_policy->tunables_hook);
643 policy->governor_data = NULL;
644 if (!count)
645 sugov_tunables_free(tunables);
646
647 mutex_unlock(&global_tunables_lock);
648
649 sugov_kthread_stop(sg_policy);
650 sugov_policy_free(sg_policy);
651 cpufreq_disable_fast_switch(policy);
652}
653
654static int sugov_start(struct cpufreq_policy *policy)
655{
656 struct sugov_policy *sg_policy = policy->governor_data;
657 unsigned int cpu;
658
659 sg_policy->freq_update_delay_ns = sg_policy->tunables->rate_limit_us * NSEC_PER_USEC;
660 sg_policy->last_freq_update_time = 0;
661 sg_policy->next_freq = UINT_MAX;
662 sg_policy->work_in_progress = false;
663 sg_policy->need_freq_update = false;
664 sg_policy->cached_raw_freq = 0;
665
666 for_each_cpu(cpu, policy->cpus) {
667 struct sugov_cpu *sg_cpu = &per_cpu(sugov_cpu, cpu);
668
669 memset(sg_cpu, 0, sizeof(*sg_cpu));
670 sg_cpu->cpu = cpu;
671 sg_cpu->sg_policy = sg_policy;
672 sg_cpu->iowait_boost_max = policy->cpuinfo.max_freq;
673 }
674
675 for_each_cpu(cpu, policy->cpus) {
676 struct sugov_cpu *sg_cpu = &per_cpu(sugov_cpu, cpu);
677
678 cpufreq_add_update_util_hook(cpu, &sg_cpu->update_util,
679 policy_is_shared(policy) ?
680 sugov_update_shared :
681 sugov_update_single);
682 }
683 return 0;
684}
685
686static void sugov_stop(struct cpufreq_policy *policy)
687{
688 struct sugov_policy *sg_policy = policy->governor_data;
689 unsigned int cpu;
690
691 for_each_cpu(cpu, policy->cpus)
692 cpufreq_remove_update_util_hook(cpu);
693
694 synchronize_sched();
695
696 if (!policy->fast_switch_enabled) {
697 irq_work_sync(&sg_policy->irq_work);
698 kthread_cancel_work_sync(&sg_policy->work);
699 }
700}
701
702static void sugov_limits(struct cpufreq_policy *policy)
703{
704 struct sugov_policy *sg_policy = policy->governor_data;
705
706 if (!policy->fast_switch_enabled) {
707 mutex_lock(&sg_policy->work_lock);
708 cpufreq_policy_apply_limits(policy);
709 mutex_unlock(&sg_policy->work_lock);
710 }
711
712 sg_policy->need_freq_update = true;
713}
714
715static struct cpufreq_governor schedutil_gov = {
716 .name = "schedutil",
717 .owner = THIS_MODULE,
718 .dynamic_switching = true,
719 .init = sugov_init,
720 .exit = sugov_exit,
721 .start = sugov_start,
722 .stop = sugov_stop,
723 .limits = sugov_limits,
724};
725
726#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_SCHEDUTIL
727struct cpufreq_governor *cpufreq_default_governor(void)
728{
729 return &schedutil_gov;
730}
731#endif
732
733static int __init sugov_register(void)
734{
735 return cpufreq_register_governor(&schedutil_gov);
736}
737fs_initcall(sugov_register);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * CPUFreq governor based on scheduler-provided CPU utilization data.
4 *
5 * Copyright (C) 2016, Intel Corporation
6 * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
7 */
8
9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
11#include "sched.h"
12
13#include <linux/sched/cpufreq.h>
14#include <trace/events/power.h>
15
16#define IOWAIT_BOOST_MIN (SCHED_CAPACITY_SCALE / 8)
17
18struct sugov_tunables {
19 struct gov_attr_set attr_set;
20 unsigned int rate_limit_us;
21};
22
23struct sugov_policy {
24 struct cpufreq_policy *policy;
25
26 struct sugov_tunables *tunables;
27 struct list_head tunables_hook;
28
29 raw_spinlock_t update_lock;
30 u64 last_freq_update_time;
31 s64 freq_update_delay_ns;
32 unsigned int next_freq;
33 unsigned int cached_raw_freq;
34
35 /* The next fields are only needed if fast switch cannot be used: */
36 struct irq_work irq_work;
37 struct kthread_work work;
38 struct mutex work_lock;
39 struct kthread_worker worker;
40 struct task_struct *thread;
41 bool work_in_progress;
42
43 bool limits_changed;
44 bool need_freq_update;
45};
46
47struct sugov_cpu {
48 struct update_util_data update_util;
49 struct sugov_policy *sg_policy;
50 unsigned int cpu;
51
52 bool iowait_boost_pending;
53 unsigned int iowait_boost;
54 u64 last_update;
55
56 unsigned long util;
57 unsigned long bw_dl;
58 unsigned long max;
59
60 /* The field below is for single-CPU policies only: */
61#ifdef CONFIG_NO_HZ_COMMON
62 unsigned long saved_idle_calls;
63#endif
64};
65
66static DEFINE_PER_CPU(struct sugov_cpu, sugov_cpu);
67
68/************************ Governor internals ***********************/
69
70static bool sugov_should_update_freq(struct sugov_policy *sg_policy, u64 time)
71{
72 s64 delta_ns;
73
74 /*
75 * Since cpufreq_update_util() is called with rq->lock held for
76 * the @target_cpu, our per-CPU data is fully serialized.
77 *
78 * However, drivers cannot in general deal with cross-CPU
79 * requests, so while get_next_freq() will work, our
80 * sugov_update_commit() call may not for the fast switching platforms.
81 *
82 * Hence stop here for remote requests if they aren't supported
83 * by the hardware, as calculating the frequency is pointless if
84 * we cannot in fact act on it.
85 *
86 * This is needed on the slow switching platforms too to prevent CPUs
87 * going offline from leaving stale IRQ work items behind.
88 */
89 if (!cpufreq_this_cpu_can_update(sg_policy->policy))
90 return false;
91
92 if (unlikely(sg_policy->limits_changed)) {
93 sg_policy->limits_changed = false;
94 sg_policy->need_freq_update = true;
95 return true;
96 }
97
98 delta_ns = time - sg_policy->last_freq_update_time;
99
100 return delta_ns >= sg_policy->freq_update_delay_ns;
101}
102
103static bool sugov_update_next_freq(struct sugov_policy *sg_policy, u64 time,
104 unsigned int next_freq)
105{
106 if (sg_policy->need_freq_update)
107 sg_policy->need_freq_update = cpufreq_driver_test_flags(CPUFREQ_NEED_UPDATE_LIMITS);
108 else if (sg_policy->next_freq == next_freq)
109 return false;
110
111 sg_policy->next_freq = next_freq;
112 sg_policy->last_freq_update_time = time;
113
114 return true;
115}
116
117static void sugov_deferred_update(struct sugov_policy *sg_policy)
118{
119 if (!sg_policy->work_in_progress) {
120 sg_policy->work_in_progress = true;
121 irq_work_queue(&sg_policy->irq_work);
122 }
123}
124
125/**
126 * get_next_freq - Compute a new frequency for a given cpufreq policy.
127 * @sg_policy: schedutil policy object to compute the new frequency for.
128 * @util: Current CPU utilization.
129 * @max: CPU capacity.
130 *
131 * If the utilization is frequency-invariant, choose the new frequency to be
132 * proportional to it, that is
133 *
134 * next_freq = C * max_freq * util / max
135 *
136 * Otherwise, approximate the would-be frequency-invariant utilization by
137 * util_raw * (curr_freq / max_freq) which leads to
138 *
139 * next_freq = C * curr_freq * util_raw / max
140 *
141 * Take C = 1.25 for the frequency tipping point at (util / max) = 0.8.
142 *
143 * The lowest driver-supported frequency which is equal or greater than the raw
144 * next_freq (as calculated above) is returned, subject to policy min/max and
145 * cpufreq driver limitations.
146 */
147static unsigned int get_next_freq(struct sugov_policy *sg_policy,
148 unsigned long util, unsigned long max)
149{
150 struct cpufreq_policy *policy = sg_policy->policy;
151 unsigned int freq = arch_scale_freq_invariant() ?
152 policy->cpuinfo.max_freq : policy->cur;
153
154 util = map_util_perf(util);
155 freq = map_util_freq(util, freq, max);
156
157 if (freq == sg_policy->cached_raw_freq && !sg_policy->need_freq_update)
158 return sg_policy->next_freq;
159
160 sg_policy->cached_raw_freq = freq;
161 return cpufreq_driver_resolve_freq(policy, freq);
162}
163
164static void sugov_get_util(struct sugov_cpu *sg_cpu)
165{
166 struct rq *rq = cpu_rq(sg_cpu->cpu);
167 unsigned long max = arch_scale_cpu_capacity(sg_cpu->cpu);
168
169 sg_cpu->max = max;
170 sg_cpu->bw_dl = cpu_bw_dl(rq);
171 sg_cpu->util = effective_cpu_util(sg_cpu->cpu, cpu_util_cfs(rq), max,
172 FREQUENCY_UTIL, NULL);
173}
174
175/**
176 * sugov_iowait_reset() - Reset the IO boost status of a CPU.
177 * @sg_cpu: the sugov data for the CPU to boost
178 * @time: the update time from the caller
179 * @set_iowait_boost: true if an IO boost has been requested
180 *
181 * The IO wait boost of a task is disabled after a tick since the last update
182 * of a CPU. If a new IO wait boost is requested after more then a tick, then
183 * we enable the boost starting from IOWAIT_BOOST_MIN, which improves energy
184 * efficiency by ignoring sporadic wakeups from IO.
185 */
186static bool sugov_iowait_reset(struct sugov_cpu *sg_cpu, u64 time,
187 bool set_iowait_boost)
188{
189 s64 delta_ns = time - sg_cpu->last_update;
190
191 /* Reset boost only if a tick has elapsed since last request */
192 if (delta_ns <= TICK_NSEC)
193 return false;
194
195 sg_cpu->iowait_boost = set_iowait_boost ? IOWAIT_BOOST_MIN : 0;
196 sg_cpu->iowait_boost_pending = set_iowait_boost;
197
198 return true;
199}
200
201/**
202 * sugov_iowait_boost() - Updates the IO boost status of a CPU.
203 * @sg_cpu: the sugov data for the CPU to boost
204 * @time: the update time from the caller
205 * @flags: SCHED_CPUFREQ_IOWAIT if the task is waking up after an IO wait
206 *
207 * Each time a task wakes up after an IO operation, the CPU utilization can be
208 * boosted to a certain utilization which doubles at each "frequent and
209 * successive" wakeup from IO, ranging from IOWAIT_BOOST_MIN to the utilization
210 * of the maximum OPP.
211 *
212 * To keep doubling, an IO boost has to be requested at least once per tick,
213 * otherwise we restart from the utilization of the minimum OPP.
214 */
215static void sugov_iowait_boost(struct sugov_cpu *sg_cpu, u64 time,
216 unsigned int flags)
217{
218 bool set_iowait_boost = flags & SCHED_CPUFREQ_IOWAIT;
219
220 /* Reset boost if the CPU appears to have been idle enough */
221 if (sg_cpu->iowait_boost &&
222 sugov_iowait_reset(sg_cpu, time, set_iowait_boost))
223 return;
224
225 /* Boost only tasks waking up after IO */
226 if (!set_iowait_boost)
227 return;
228
229 /* Ensure boost doubles only one time at each request */
230 if (sg_cpu->iowait_boost_pending)
231 return;
232 sg_cpu->iowait_boost_pending = true;
233
234 /* Double the boost at each request */
235 if (sg_cpu->iowait_boost) {
236 sg_cpu->iowait_boost =
237 min_t(unsigned int, sg_cpu->iowait_boost << 1, SCHED_CAPACITY_SCALE);
238 return;
239 }
240
241 /* First wakeup after IO: start with minimum boost */
242 sg_cpu->iowait_boost = IOWAIT_BOOST_MIN;
243}
244
245/**
246 * sugov_iowait_apply() - Apply the IO boost to a CPU.
247 * @sg_cpu: the sugov data for the cpu to boost
248 * @time: the update time from the caller
249 *
250 * A CPU running a task which woken up after an IO operation can have its
251 * utilization boosted to speed up the completion of those IO operations.
252 * The IO boost value is increased each time a task wakes up from IO, in
253 * sugov_iowait_apply(), and it's instead decreased by this function,
254 * each time an increase has not been requested (!iowait_boost_pending).
255 *
256 * A CPU which also appears to have been idle for at least one tick has also
257 * its IO boost utilization reset.
258 *
259 * This mechanism is designed to boost high frequently IO waiting tasks, while
260 * being more conservative on tasks which does sporadic IO operations.
261 */
262static void sugov_iowait_apply(struct sugov_cpu *sg_cpu, u64 time)
263{
264 unsigned long boost;
265
266 /* No boost currently required */
267 if (!sg_cpu->iowait_boost)
268 return;
269
270 /* Reset boost if the CPU appears to have been idle enough */
271 if (sugov_iowait_reset(sg_cpu, time, false))
272 return;
273
274 if (!sg_cpu->iowait_boost_pending) {
275 /*
276 * No boost pending; reduce the boost value.
277 */
278 sg_cpu->iowait_boost >>= 1;
279 if (sg_cpu->iowait_boost < IOWAIT_BOOST_MIN) {
280 sg_cpu->iowait_boost = 0;
281 return;
282 }
283 }
284
285 sg_cpu->iowait_boost_pending = false;
286
287 /*
288 * sg_cpu->util is already in capacity scale; convert iowait_boost
289 * into the same scale so we can compare.
290 */
291 boost = (sg_cpu->iowait_boost * sg_cpu->max) >> SCHED_CAPACITY_SHIFT;
292 if (sg_cpu->util < boost)
293 sg_cpu->util = boost;
294}
295
296#ifdef CONFIG_NO_HZ_COMMON
297static bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu)
298{
299 unsigned long idle_calls = tick_nohz_get_idle_calls_cpu(sg_cpu->cpu);
300 bool ret = idle_calls == sg_cpu->saved_idle_calls;
301
302 sg_cpu->saved_idle_calls = idle_calls;
303 return ret;
304}
305#else
306static inline bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu) { return false; }
307#endif /* CONFIG_NO_HZ_COMMON */
308
309/*
310 * Make sugov_should_update_freq() ignore the rate limit when DL
311 * has increased the utilization.
312 */
313static inline void ignore_dl_rate_limit(struct sugov_cpu *sg_cpu)
314{
315 if (cpu_bw_dl(cpu_rq(sg_cpu->cpu)) > sg_cpu->bw_dl)
316 sg_cpu->sg_policy->limits_changed = true;
317}
318
319static inline bool sugov_update_single_common(struct sugov_cpu *sg_cpu,
320 u64 time, unsigned int flags)
321{
322 sugov_iowait_boost(sg_cpu, time, flags);
323 sg_cpu->last_update = time;
324
325 ignore_dl_rate_limit(sg_cpu);
326
327 if (!sugov_should_update_freq(sg_cpu->sg_policy, time))
328 return false;
329
330 sugov_get_util(sg_cpu);
331 sugov_iowait_apply(sg_cpu, time);
332
333 return true;
334}
335
336static void sugov_update_single_freq(struct update_util_data *hook, u64 time,
337 unsigned int flags)
338{
339 struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
340 struct sugov_policy *sg_policy = sg_cpu->sg_policy;
341 unsigned int cached_freq = sg_policy->cached_raw_freq;
342 unsigned int next_f;
343
344 if (!sugov_update_single_common(sg_cpu, time, flags))
345 return;
346
347 next_f = get_next_freq(sg_policy, sg_cpu->util, sg_cpu->max);
348 /*
349 * Do not reduce the frequency if the CPU has not been idle
350 * recently, as the reduction is likely to be premature then.
351 */
352 if (sugov_cpu_is_busy(sg_cpu) && next_f < sg_policy->next_freq) {
353 next_f = sg_policy->next_freq;
354
355 /* Restore cached freq as next_freq has changed */
356 sg_policy->cached_raw_freq = cached_freq;
357 }
358
359 if (!sugov_update_next_freq(sg_policy, time, next_f))
360 return;
361
362 /*
363 * This code runs under rq->lock for the target CPU, so it won't run
364 * concurrently on two different CPUs for the same target and it is not
365 * necessary to acquire the lock in the fast switch case.
366 */
367 if (sg_policy->policy->fast_switch_enabled) {
368 cpufreq_driver_fast_switch(sg_policy->policy, next_f);
369 } else {
370 raw_spin_lock(&sg_policy->update_lock);
371 sugov_deferred_update(sg_policy);
372 raw_spin_unlock(&sg_policy->update_lock);
373 }
374}
375
376static void sugov_update_single_perf(struct update_util_data *hook, u64 time,
377 unsigned int flags)
378{
379 struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
380 unsigned long prev_util = sg_cpu->util;
381
382 /*
383 * Fall back to the "frequency" path if frequency invariance is not
384 * supported, because the direct mapping between the utilization and
385 * the performance levels depends on the frequency invariance.
386 */
387 if (!arch_scale_freq_invariant()) {
388 sugov_update_single_freq(hook, time, flags);
389 return;
390 }
391
392 if (!sugov_update_single_common(sg_cpu, time, flags))
393 return;
394
395 /*
396 * Do not reduce the target performance level if the CPU has not been
397 * idle recently, as the reduction is likely to be premature then.
398 */
399 if (sugov_cpu_is_busy(sg_cpu) && sg_cpu->util < prev_util)
400 sg_cpu->util = prev_util;
401
402 cpufreq_driver_adjust_perf(sg_cpu->cpu, map_util_perf(sg_cpu->bw_dl),
403 map_util_perf(sg_cpu->util), sg_cpu->max);
404
405 sg_cpu->sg_policy->last_freq_update_time = time;
406}
407
408static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu, u64 time)
409{
410 struct sugov_policy *sg_policy = sg_cpu->sg_policy;
411 struct cpufreq_policy *policy = sg_policy->policy;
412 unsigned long util = 0, max = 1;
413 unsigned int j;
414
415 for_each_cpu(j, policy->cpus) {
416 struct sugov_cpu *j_sg_cpu = &per_cpu(sugov_cpu, j);
417 unsigned long j_util, j_max;
418
419 sugov_get_util(j_sg_cpu);
420 sugov_iowait_apply(j_sg_cpu, time);
421 j_util = j_sg_cpu->util;
422 j_max = j_sg_cpu->max;
423
424 if (j_util * max > j_max * util) {
425 util = j_util;
426 max = j_max;
427 }
428 }
429
430 return get_next_freq(sg_policy, util, max);
431}
432
433static void
434sugov_update_shared(struct update_util_data *hook, u64 time, unsigned int flags)
435{
436 struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
437 struct sugov_policy *sg_policy = sg_cpu->sg_policy;
438 unsigned int next_f;
439
440 raw_spin_lock(&sg_policy->update_lock);
441
442 sugov_iowait_boost(sg_cpu, time, flags);
443 sg_cpu->last_update = time;
444
445 ignore_dl_rate_limit(sg_cpu);
446
447 if (sugov_should_update_freq(sg_policy, time)) {
448 next_f = sugov_next_freq_shared(sg_cpu, time);
449
450 if (!sugov_update_next_freq(sg_policy, time, next_f))
451 goto unlock;
452
453 if (sg_policy->policy->fast_switch_enabled)
454 cpufreq_driver_fast_switch(sg_policy->policy, next_f);
455 else
456 sugov_deferred_update(sg_policy);
457 }
458unlock:
459 raw_spin_unlock(&sg_policy->update_lock);
460}
461
462static void sugov_work(struct kthread_work *work)
463{
464 struct sugov_policy *sg_policy = container_of(work, struct sugov_policy, work);
465 unsigned int freq;
466 unsigned long flags;
467
468 /*
469 * Hold sg_policy->update_lock shortly to handle the case where:
470 * in case sg_policy->next_freq is read here, and then updated by
471 * sugov_deferred_update() just before work_in_progress is set to false
472 * here, we may miss queueing the new update.
473 *
474 * Note: If a work was queued after the update_lock is released,
475 * sugov_work() will just be called again by kthread_work code; and the
476 * request will be proceed before the sugov thread sleeps.
477 */
478 raw_spin_lock_irqsave(&sg_policy->update_lock, flags);
479 freq = sg_policy->next_freq;
480 sg_policy->work_in_progress = false;
481 raw_spin_unlock_irqrestore(&sg_policy->update_lock, flags);
482
483 mutex_lock(&sg_policy->work_lock);
484 __cpufreq_driver_target(sg_policy->policy, freq, CPUFREQ_RELATION_L);
485 mutex_unlock(&sg_policy->work_lock);
486}
487
488static void sugov_irq_work(struct irq_work *irq_work)
489{
490 struct sugov_policy *sg_policy;
491
492 sg_policy = container_of(irq_work, struct sugov_policy, irq_work);
493
494 kthread_queue_work(&sg_policy->worker, &sg_policy->work);
495}
496
497/************************** sysfs interface ************************/
498
499static struct sugov_tunables *global_tunables;
500static DEFINE_MUTEX(global_tunables_lock);
501
502static inline struct sugov_tunables *to_sugov_tunables(struct gov_attr_set *attr_set)
503{
504 return container_of(attr_set, struct sugov_tunables, attr_set);
505}
506
507static ssize_t rate_limit_us_show(struct gov_attr_set *attr_set, char *buf)
508{
509 struct sugov_tunables *tunables = to_sugov_tunables(attr_set);
510
511 return sprintf(buf, "%u\n", tunables->rate_limit_us);
512}
513
514static ssize_t
515rate_limit_us_store(struct gov_attr_set *attr_set, const char *buf, size_t count)
516{
517 struct sugov_tunables *tunables = to_sugov_tunables(attr_set);
518 struct sugov_policy *sg_policy;
519 unsigned int rate_limit_us;
520
521 if (kstrtouint(buf, 10, &rate_limit_us))
522 return -EINVAL;
523
524 tunables->rate_limit_us = rate_limit_us;
525
526 list_for_each_entry(sg_policy, &attr_set->policy_list, tunables_hook)
527 sg_policy->freq_update_delay_ns = rate_limit_us * NSEC_PER_USEC;
528
529 return count;
530}
531
532static struct governor_attr rate_limit_us = __ATTR_RW(rate_limit_us);
533
534static struct attribute *sugov_attrs[] = {
535 &rate_limit_us.attr,
536 NULL
537};
538ATTRIBUTE_GROUPS(sugov);
539
540static void sugov_tunables_free(struct kobject *kobj)
541{
542 struct gov_attr_set *attr_set = container_of(kobj, struct gov_attr_set, kobj);
543
544 kfree(to_sugov_tunables(attr_set));
545}
546
547static struct kobj_type sugov_tunables_ktype = {
548 .default_groups = sugov_groups,
549 .sysfs_ops = &governor_sysfs_ops,
550 .release = &sugov_tunables_free,
551};
552
553/********************** cpufreq governor interface *********************/
554
555struct cpufreq_governor schedutil_gov;
556
557static struct sugov_policy *sugov_policy_alloc(struct cpufreq_policy *policy)
558{
559 struct sugov_policy *sg_policy;
560
561 sg_policy = kzalloc(sizeof(*sg_policy), GFP_KERNEL);
562 if (!sg_policy)
563 return NULL;
564
565 sg_policy->policy = policy;
566 raw_spin_lock_init(&sg_policy->update_lock);
567 return sg_policy;
568}
569
570static void sugov_policy_free(struct sugov_policy *sg_policy)
571{
572 kfree(sg_policy);
573}
574
575static int sugov_kthread_create(struct sugov_policy *sg_policy)
576{
577 struct task_struct *thread;
578 struct sched_attr attr = {
579 .size = sizeof(struct sched_attr),
580 .sched_policy = SCHED_DEADLINE,
581 .sched_flags = SCHED_FLAG_SUGOV,
582 .sched_nice = 0,
583 .sched_priority = 0,
584 /*
585 * Fake (unused) bandwidth; workaround to "fix"
586 * priority inheritance.
587 */
588 .sched_runtime = 1000000,
589 .sched_deadline = 10000000,
590 .sched_period = 10000000,
591 };
592 struct cpufreq_policy *policy = sg_policy->policy;
593 int ret;
594
595 /* kthread only required for slow path */
596 if (policy->fast_switch_enabled)
597 return 0;
598
599 kthread_init_work(&sg_policy->work, sugov_work);
600 kthread_init_worker(&sg_policy->worker);
601 thread = kthread_create(kthread_worker_fn, &sg_policy->worker,
602 "sugov:%d",
603 cpumask_first(policy->related_cpus));
604 if (IS_ERR(thread)) {
605 pr_err("failed to create sugov thread: %ld\n", PTR_ERR(thread));
606 return PTR_ERR(thread);
607 }
608
609 ret = sched_setattr_nocheck(thread, &attr);
610 if (ret) {
611 kthread_stop(thread);
612 pr_warn("%s: failed to set SCHED_DEADLINE\n", __func__);
613 return ret;
614 }
615
616 sg_policy->thread = thread;
617 kthread_bind_mask(thread, policy->related_cpus);
618 init_irq_work(&sg_policy->irq_work, sugov_irq_work);
619 mutex_init(&sg_policy->work_lock);
620
621 wake_up_process(thread);
622
623 return 0;
624}
625
626static void sugov_kthread_stop(struct sugov_policy *sg_policy)
627{
628 /* kthread only required for slow path */
629 if (sg_policy->policy->fast_switch_enabled)
630 return;
631
632 kthread_flush_worker(&sg_policy->worker);
633 kthread_stop(sg_policy->thread);
634 mutex_destroy(&sg_policy->work_lock);
635}
636
637static struct sugov_tunables *sugov_tunables_alloc(struct sugov_policy *sg_policy)
638{
639 struct sugov_tunables *tunables;
640
641 tunables = kzalloc(sizeof(*tunables), GFP_KERNEL);
642 if (tunables) {
643 gov_attr_set_init(&tunables->attr_set, &sg_policy->tunables_hook);
644 if (!have_governor_per_policy())
645 global_tunables = tunables;
646 }
647 return tunables;
648}
649
650static void sugov_clear_global_tunables(void)
651{
652 if (!have_governor_per_policy())
653 global_tunables = NULL;
654}
655
656static int sugov_init(struct cpufreq_policy *policy)
657{
658 struct sugov_policy *sg_policy;
659 struct sugov_tunables *tunables;
660 int ret = 0;
661
662 /* State should be equivalent to EXIT */
663 if (policy->governor_data)
664 return -EBUSY;
665
666 cpufreq_enable_fast_switch(policy);
667
668 sg_policy = sugov_policy_alloc(policy);
669 if (!sg_policy) {
670 ret = -ENOMEM;
671 goto disable_fast_switch;
672 }
673
674 ret = sugov_kthread_create(sg_policy);
675 if (ret)
676 goto free_sg_policy;
677
678 mutex_lock(&global_tunables_lock);
679
680 if (global_tunables) {
681 if (WARN_ON(have_governor_per_policy())) {
682 ret = -EINVAL;
683 goto stop_kthread;
684 }
685 policy->governor_data = sg_policy;
686 sg_policy->tunables = global_tunables;
687
688 gov_attr_set_get(&global_tunables->attr_set, &sg_policy->tunables_hook);
689 goto out;
690 }
691
692 tunables = sugov_tunables_alloc(sg_policy);
693 if (!tunables) {
694 ret = -ENOMEM;
695 goto stop_kthread;
696 }
697
698 tunables->rate_limit_us = cpufreq_policy_transition_delay_us(policy);
699
700 policy->governor_data = sg_policy;
701 sg_policy->tunables = tunables;
702
703 ret = kobject_init_and_add(&tunables->attr_set.kobj, &sugov_tunables_ktype,
704 get_governor_parent_kobj(policy), "%s",
705 schedutil_gov.name);
706 if (ret)
707 goto fail;
708
709out:
710 mutex_unlock(&global_tunables_lock);
711 return 0;
712
713fail:
714 kobject_put(&tunables->attr_set.kobj);
715 policy->governor_data = NULL;
716 sugov_clear_global_tunables();
717
718stop_kthread:
719 sugov_kthread_stop(sg_policy);
720 mutex_unlock(&global_tunables_lock);
721
722free_sg_policy:
723 sugov_policy_free(sg_policy);
724
725disable_fast_switch:
726 cpufreq_disable_fast_switch(policy);
727
728 pr_err("initialization failed (error %d)\n", ret);
729 return ret;
730}
731
732static void sugov_exit(struct cpufreq_policy *policy)
733{
734 struct sugov_policy *sg_policy = policy->governor_data;
735 struct sugov_tunables *tunables = sg_policy->tunables;
736 unsigned int count;
737
738 mutex_lock(&global_tunables_lock);
739
740 count = gov_attr_set_put(&tunables->attr_set, &sg_policy->tunables_hook);
741 policy->governor_data = NULL;
742 if (!count)
743 sugov_clear_global_tunables();
744
745 mutex_unlock(&global_tunables_lock);
746
747 sugov_kthread_stop(sg_policy);
748 sugov_policy_free(sg_policy);
749 cpufreq_disable_fast_switch(policy);
750}
751
752static int sugov_start(struct cpufreq_policy *policy)
753{
754 struct sugov_policy *sg_policy = policy->governor_data;
755 void (*uu)(struct update_util_data *data, u64 time, unsigned int flags);
756 unsigned int cpu;
757
758 sg_policy->freq_update_delay_ns = sg_policy->tunables->rate_limit_us * NSEC_PER_USEC;
759 sg_policy->last_freq_update_time = 0;
760 sg_policy->next_freq = 0;
761 sg_policy->work_in_progress = false;
762 sg_policy->limits_changed = false;
763 sg_policy->cached_raw_freq = 0;
764
765 sg_policy->need_freq_update = cpufreq_driver_test_flags(CPUFREQ_NEED_UPDATE_LIMITS);
766
767 for_each_cpu(cpu, policy->cpus) {
768 struct sugov_cpu *sg_cpu = &per_cpu(sugov_cpu, cpu);
769
770 memset(sg_cpu, 0, sizeof(*sg_cpu));
771 sg_cpu->cpu = cpu;
772 sg_cpu->sg_policy = sg_policy;
773 }
774
775 if (policy_is_shared(policy))
776 uu = sugov_update_shared;
777 else if (policy->fast_switch_enabled && cpufreq_driver_has_adjust_perf())
778 uu = sugov_update_single_perf;
779 else
780 uu = sugov_update_single_freq;
781
782 for_each_cpu(cpu, policy->cpus) {
783 struct sugov_cpu *sg_cpu = &per_cpu(sugov_cpu, cpu);
784
785 cpufreq_add_update_util_hook(cpu, &sg_cpu->update_util, uu);
786 }
787 return 0;
788}
789
790static void sugov_stop(struct cpufreq_policy *policy)
791{
792 struct sugov_policy *sg_policy = policy->governor_data;
793 unsigned int cpu;
794
795 for_each_cpu(cpu, policy->cpus)
796 cpufreq_remove_update_util_hook(cpu);
797
798 synchronize_rcu();
799
800 if (!policy->fast_switch_enabled) {
801 irq_work_sync(&sg_policy->irq_work);
802 kthread_cancel_work_sync(&sg_policy->work);
803 }
804}
805
806static void sugov_limits(struct cpufreq_policy *policy)
807{
808 struct sugov_policy *sg_policy = policy->governor_data;
809
810 if (!policy->fast_switch_enabled) {
811 mutex_lock(&sg_policy->work_lock);
812 cpufreq_policy_apply_limits(policy);
813 mutex_unlock(&sg_policy->work_lock);
814 }
815
816 sg_policy->limits_changed = true;
817}
818
819struct cpufreq_governor schedutil_gov = {
820 .name = "schedutil",
821 .owner = THIS_MODULE,
822 .flags = CPUFREQ_GOV_DYNAMIC_SWITCHING,
823 .init = sugov_init,
824 .exit = sugov_exit,
825 .start = sugov_start,
826 .stop = sugov_stop,
827 .limits = sugov_limits,
828};
829
830#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_SCHEDUTIL
831struct cpufreq_governor *cpufreq_default_governor(void)
832{
833 return &schedutil_gov;
834}
835#endif
836
837cpufreq_governor_init(schedutil_gov);
838
839#ifdef CONFIG_ENERGY_MODEL
840static void rebuild_sd_workfn(struct work_struct *work)
841{
842 rebuild_sched_domains_energy();
843}
844static DECLARE_WORK(rebuild_sd_work, rebuild_sd_workfn);
845
846/*
847 * EAS shouldn't be attempted without sugov, so rebuild the sched_domains
848 * on governor changes to make sure the scheduler knows about it.
849 */
850void sched_cpufreq_governor_change(struct cpufreq_policy *policy,
851 struct cpufreq_governor *old_gov)
852{
853 if (old_gov == &schedutil_gov || policy->governor == &schedutil_gov) {
854 /*
855 * When called from the cpufreq_register_driver() path, the
856 * cpu_hotplug_lock is already held, so use a work item to
857 * avoid nested locking in rebuild_sched_domains().
858 */
859 schedule_work(&rebuild_sd_work);
860 }
861
862}
863#endif