dd062a1c8cf043a26882e3b694d7c15588a2718c
[sfrench/cifs-2.6.git] / kernel / sched / cpufreq_schedutil.c
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 <linux/cpufreq.h>
15 #include <linux/kthread.h>
16 #include <uapi/linux/sched/types.h>
17 #include <linux/slab.h>
18 #include <trace/events/power.h>
19
20 #include "sched.h"
21
22 #define SUGOV_KTHREAD_PRIORITY  50
23
24 struct sugov_tunables {
25         struct gov_attr_set attr_set;
26         unsigned int rate_limit_us;
27 };
28
29 struct sugov_policy {
30         struct cpufreq_policy *policy;
31
32         struct sugov_tunables *tunables;
33         struct list_head tunables_hook;
34
35         raw_spinlock_t update_lock;  /* For shared policies */
36         u64 last_freq_update_time;
37         s64 freq_update_delay_ns;
38         unsigned int next_freq;
39         unsigned int cached_raw_freq;
40
41         /* The next fields are only needed if fast switch cannot be used. */
42         struct irq_work irq_work;
43         struct kthread_work work;
44         struct mutex work_lock;
45         struct kthread_worker worker;
46         struct task_struct *thread;
47         bool work_in_progress;
48
49         bool need_freq_update;
50 };
51
52 struct sugov_cpu {
53         struct update_util_data update_util;
54         struct sugov_policy *sg_policy;
55         unsigned int cpu;
56
57         bool iowait_boost_pending;
58         unsigned int iowait_boost;
59         unsigned int iowait_boost_max;
60         u64 last_update;
61
62         /* The fields below are only needed when sharing a policy. */
63         unsigned long util_cfs;
64         unsigned long util_dl;
65         unsigned long max;
66         unsigned int flags;
67
68         /* The field below is for single-CPU policies only. */
69 #ifdef CONFIG_NO_HZ_COMMON
70         unsigned long saved_idle_calls;
71 #endif
72 };
73
74 static DEFINE_PER_CPU(struct sugov_cpu, sugov_cpu);
75
76 /************************ Governor internals ***********************/
77
78 static bool sugov_should_update_freq(struct sugov_policy *sg_policy, u64 time)
79 {
80         s64 delta_ns;
81
82         /*
83          * Since cpufreq_update_util() is called with rq->lock held for
84          * the @target_cpu, our per-cpu data is fully serialized.
85          *
86          * However, drivers cannot in general deal with cross-cpu
87          * requests, so while get_next_freq() will work, our
88          * sugov_update_commit() call may not for the fast switching platforms.
89          *
90          * Hence stop here for remote requests if they aren't supported
91          * by the hardware, as calculating the frequency is pointless if
92          * we cannot in fact act on it.
93          *
94          * For the slow switching platforms, the kthread is always scheduled on
95          * the right set of CPUs and any CPU can find the next frequency and
96          * schedule the kthread.
97          */
98         if (sg_policy->policy->fast_switch_enabled &&
99             !cpufreq_can_do_remote_dvfs(sg_policy->policy))
100                 return false;
101
102         if (sg_policy->work_in_progress)
103                 return false;
104
105         if (unlikely(sg_policy->need_freq_update)) {
106                 sg_policy->need_freq_update = false;
107                 /*
108                  * This happens when limits change, so forget the previous
109                  * next_freq value and force an update.
110                  */
111                 sg_policy->next_freq = UINT_MAX;
112                 return true;
113         }
114
115         delta_ns = time - sg_policy->last_freq_update_time;
116         return delta_ns >= sg_policy->freq_update_delay_ns;
117 }
118
119 static void sugov_update_commit(struct sugov_policy *sg_policy, u64 time,
120                                 unsigned int next_freq)
121 {
122         struct cpufreq_policy *policy = sg_policy->policy;
123
124         if (sg_policy->next_freq == next_freq)
125                 return;
126
127         sg_policy->next_freq = next_freq;
128         sg_policy->last_freq_update_time = time;
129
130         if (policy->fast_switch_enabled) {
131                 next_freq = cpufreq_driver_fast_switch(policy, next_freq);
132                 if (!next_freq)
133                         return;
134
135                 policy->cur = next_freq;
136                 trace_cpu_frequency(next_freq, smp_processor_id());
137         } else {
138                 sg_policy->work_in_progress = true;
139                 irq_work_queue(&sg_policy->irq_work);
140         }
141 }
142
143 /**
144  * get_next_freq - Compute a new frequency for a given cpufreq policy.
145  * @sg_policy: schedutil policy object to compute the new frequency for.
146  * @util: Current CPU utilization.
147  * @max: CPU capacity.
148  *
149  * If the utilization is frequency-invariant, choose the new frequency to be
150  * proportional to it, that is
151  *
152  * next_freq = C * max_freq * util / max
153  *
154  * Otherwise, approximate the would-be frequency-invariant utilization by
155  * util_raw * (curr_freq / max_freq) which leads to
156  *
157  * next_freq = C * curr_freq * util_raw / max
158  *
159  * Take C = 1.25 for the frequency tipping point at (util / max) = 0.8.
160  *
161  * The lowest driver-supported frequency which is equal or greater than the raw
162  * next_freq (as calculated above) is returned, subject to policy min/max and
163  * cpufreq driver limitations.
164  */
165 static unsigned int get_next_freq(struct sugov_policy *sg_policy,
166                                   unsigned long util, unsigned long max)
167 {
168         struct cpufreq_policy *policy = sg_policy->policy;
169         unsigned int freq = arch_scale_freq_invariant() ?
170                                 policy->cpuinfo.max_freq : policy->cur;
171
172         freq = (freq + (freq >> 2)) * util / max;
173
174         if (freq == sg_policy->cached_raw_freq && sg_policy->next_freq != UINT_MAX)
175                 return sg_policy->next_freq;
176         sg_policy->cached_raw_freq = freq;
177         return cpufreq_driver_resolve_freq(policy, freq);
178 }
179
180 static void sugov_get_util(struct sugov_cpu *sg_cpu)
181 {
182         struct rq *rq = cpu_rq(sg_cpu->cpu);
183
184         sg_cpu->max = arch_scale_cpu_capacity(NULL, sg_cpu->cpu);
185         sg_cpu->util_cfs = cpu_util_cfs(rq);
186         sg_cpu->util_dl  = cpu_util_dl(rq);
187 }
188
189 static unsigned long sugov_aggregate_util(struct sugov_cpu *sg_cpu)
190 {
191         /*
192          * Ideally we would like to set util_dl as min/guaranteed freq and
193          * util_cfs + util_dl as requested freq. However, cpufreq is not yet
194          * ready for such an interface. So, we only do the latter for now.
195          */
196         return min(sg_cpu->util_cfs + sg_cpu->util_dl, sg_cpu->max);
197 }
198
199 static void sugov_set_iowait_boost(struct sugov_cpu *sg_cpu, u64 time)
200 {
201         if (sg_cpu->flags & SCHED_CPUFREQ_IOWAIT) {
202                 if (sg_cpu->iowait_boost_pending)
203                         return;
204
205                 sg_cpu->iowait_boost_pending = true;
206
207                 if (sg_cpu->iowait_boost) {
208                         sg_cpu->iowait_boost <<= 1;
209                         if (sg_cpu->iowait_boost > sg_cpu->iowait_boost_max)
210                                 sg_cpu->iowait_boost = sg_cpu->iowait_boost_max;
211                 } else {
212                         sg_cpu->iowait_boost = sg_cpu->sg_policy->policy->min;
213                 }
214         } else if (sg_cpu->iowait_boost) {
215                 s64 delta_ns = time - sg_cpu->last_update;
216
217                 /* Clear iowait_boost if the CPU apprears to have been idle. */
218                 if (delta_ns > TICK_NSEC) {
219                         sg_cpu->iowait_boost = 0;
220                         sg_cpu->iowait_boost_pending = false;
221                 }
222         }
223 }
224
225 static void sugov_iowait_boost(struct sugov_cpu *sg_cpu, unsigned long *util,
226                                unsigned long *max)
227 {
228         unsigned int boost_util, boost_max;
229
230         if (!sg_cpu->iowait_boost)
231                 return;
232
233         if (sg_cpu->iowait_boost_pending) {
234                 sg_cpu->iowait_boost_pending = false;
235         } else {
236                 sg_cpu->iowait_boost >>= 1;
237                 if (sg_cpu->iowait_boost < sg_cpu->sg_policy->policy->min) {
238                         sg_cpu->iowait_boost = 0;
239                         return;
240                 }
241         }
242
243         boost_util = sg_cpu->iowait_boost;
244         boost_max = sg_cpu->iowait_boost_max;
245
246         if (*util * boost_max < *max * boost_util) {
247                 *util = boost_util;
248                 *max = boost_max;
249         }
250 }
251
252 #ifdef CONFIG_NO_HZ_COMMON
253 static bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu)
254 {
255         unsigned long idle_calls = tick_nohz_get_idle_calls_cpu(sg_cpu->cpu);
256         bool ret = idle_calls == sg_cpu->saved_idle_calls;
257
258         sg_cpu->saved_idle_calls = idle_calls;
259         return ret;
260 }
261 #else
262 static inline bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu) { return false; }
263 #endif /* CONFIG_NO_HZ_COMMON */
264
265 static void sugov_update_single(struct update_util_data *hook, u64 time,
266                                 unsigned int flags)
267 {
268         struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
269         struct sugov_policy *sg_policy = sg_cpu->sg_policy;
270         struct cpufreq_policy *policy = sg_policy->policy;
271         unsigned long util, max;
272         unsigned int next_f;
273         bool busy;
274
275         sugov_set_iowait_boost(sg_cpu, time);
276         sg_cpu->last_update = time;
277
278         if (!sugov_should_update_freq(sg_policy, time))
279                 return;
280
281         busy = sugov_cpu_is_busy(sg_cpu);
282
283         if (flags & SCHED_CPUFREQ_RT) {
284                 next_f = policy->cpuinfo.max_freq;
285         } else {
286                 sugov_get_util(sg_cpu);
287                 max = sg_cpu->max;
288                 util = sugov_aggregate_util(sg_cpu);
289                 sugov_iowait_boost(sg_cpu, &util, &max);
290                 next_f = get_next_freq(sg_policy, util, max);
291                 /*
292                  * Do not reduce the frequency if the CPU has not been idle
293                  * recently, as the reduction is likely to be premature then.
294                  */
295                 if (busy && next_f < sg_policy->next_freq) {
296                         next_f = sg_policy->next_freq;
297
298                         /* Reset cached freq as next_freq has changed */
299                         sg_policy->cached_raw_freq = 0;
300                 }
301         }
302         sugov_update_commit(sg_policy, time, next_f);
303 }
304
305 static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu, u64 time)
306 {
307         struct sugov_policy *sg_policy = sg_cpu->sg_policy;
308         struct cpufreq_policy *policy = sg_policy->policy;
309         unsigned long util = 0, max = 1;
310         unsigned int j;
311
312         for_each_cpu(j, policy->cpus) {
313                 struct sugov_cpu *j_sg_cpu = &per_cpu(sugov_cpu, j);
314                 unsigned long j_util, j_max;
315                 s64 delta_ns;
316
317                 /*
318                  * If the CFS CPU utilization was last updated before the
319                  * previous frequency update and the time elapsed between the
320                  * last update of the CPU utilization and the last frequency
321                  * update is long enough, reset iowait_boost and util_cfs, as
322                  * they are now probably stale. However, still consider the
323                  * CPU contribution if it has some DEADLINE utilization
324                  * (util_dl).
325                  */
326                 delta_ns = time - j_sg_cpu->last_update;
327                 if (delta_ns > TICK_NSEC) {
328                         j_sg_cpu->iowait_boost = 0;
329                         j_sg_cpu->iowait_boost_pending = false;
330                         j_sg_cpu->util_cfs = 0;
331                         if (j_sg_cpu->util_dl == 0)
332                                 continue;
333                 }
334                 if (j_sg_cpu->flags & SCHED_CPUFREQ_RT)
335                         return policy->cpuinfo.max_freq;
336
337                 j_max = j_sg_cpu->max;
338                 j_util = sugov_aggregate_util(j_sg_cpu);
339                 if (j_util * max > j_max * util) {
340                         util = j_util;
341                         max = j_max;
342                 }
343
344                 sugov_iowait_boost(j_sg_cpu, &util, &max);
345         }
346
347         return get_next_freq(sg_policy, util, max);
348 }
349
350 static void sugov_update_shared(struct update_util_data *hook, u64 time,
351                                 unsigned int flags)
352 {
353         struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
354         struct sugov_policy *sg_policy = sg_cpu->sg_policy;
355         unsigned int next_f;
356
357         raw_spin_lock(&sg_policy->update_lock);
358
359         sugov_get_util(sg_cpu);
360         sg_cpu->flags = flags;
361
362         sugov_set_iowait_boost(sg_cpu, time);
363         sg_cpu->last_update = time;
364
365         if (sugov_should_update_freq(sg_policy, time)) {
366                 if (flags & SCHED_CPUFREQ_RT)
367                         next_f = sg_policy->policy->cpuinfo.max_freq;
368                 else
369                         next_f = sugov_next_freq_shared(sg_cpu, time);
370
371                 sugov_update_commit(sg_policy, time, next_f);
372         }
373
374         raw_spin_unlock(&sg_policy->update_lock);
375 }
376
377 static void sugov_work(struct kthread_work *work)
378 {
379         struct sugov_policy *sg_policy = container_of(work, struct sugov_policy, work);
380
381         mutex_lock(&sg_policy->work_lock);
382         __cpufreq_driver_target(sg_policy->policy, sg_policy->next_freq,
383                                 CPUFREQ_RELATION_L);
384         mutex_unlock(&sg_policy->work_lock);
385
386         sg_policy->work_in_progress = false;
387 }
388
389 static void sugov_irq_work(struct irq_work *irq_work)
390 {
391         struct sugov_policy *sg_policy;
392
393         sg_policy = container_of(irq_work, struct sugov_policy, irq_work);
394
395         /*
396          * For RT tasks, the schedutil governor shoots the frequency to maximum.
397          * Special care must be taken to ensure that this kthread doesn't result
398          * in the same behavior.
399          *
400          * This is (mostly) guaranteed by the work_in_progress flag. The flag is
401          * updated only at the end of the sugov_work() function and before that
402          * the schedutil governor rejects all other frequency scaling requests.
403          *
404          * There is a very rare case though, where the RT thread yields right
405          * after the work_in_progress flag is cleared. The effects of that are
406          * neglected for now.
407          */
408         kthread_queue_work(&sg_policy->worker, &sg_policy->work);
409 }
410
411 /************************** sysfs interface ************************/
412
413 static struct sugov_tunables *global_tunables;
414 static DEFINE_MUTEX(global_tunables_lock);
415
416 static inline struct sugov_tunables *to_sugov_tunables(struct gov_attr_set *attr_set)
417 {
418         return container_of(attr_set, struct sugov_tunables, attr_set);
419 }
420
421 static ssize_t rate_limit_us_show(struct gov_attr_set *attr_set, char *buf)
422 {
423         struct sugov_tunables *tunables = to_sugov_tunables(attr_set);
424
425         return sprintf(buf, "%u\n", tunables->rate_limit_us);
426 }
427
428 static ssize_t rate_limit_us_store(struct gov_attr_set *attr_set, const char *buf,
429                                    size_t count)
430 {
431         struct sugov_tunables *tunables = to_sugov_tunables(attr_set);
432         struct sugov_policy *sg_policy;
433         unsigned int rate_limit_us;
434
435         if (kstrtouint(buf, 10, &rate_limit_us))
436                 return -EINVAL;
437
438         tunables->rate_limit_us = rate_limit_us;
439
440         list_for_each_entry(sg_policy, &attr_set->policy_list, tunables_hook)
441                 sg_policy->freq_update_delay_ns = rate_limit_us * NSEC_PER_USEC;
442
443         return count;
444 }
445
446 static struct governor_attr rate_limit_us = __ATTR_RW(rate_limit_us);
447
448 static struct attribute *sugov_attributes[] = {
449         &rate_limit_us.attr,
450         NULL
451 };
452
453 static struct kobj_type sugov_tunables_ktype = {
454         .default_attrs = sugov_attributes,
455         .sysfs_ops = &governor_sysfs_ops,
456 };
457
458 /********************** cpufreq governor interface *********************/
459
460 static struct cpufreq_governor schedutil_gov;
461
462 static struct sugov_policy *sugov_policy_alloc(struct cpufreq_policy *policy)
463 {
464         struct sugov_policy *sg_policy;
465
466         sg_policy = kzalloc(sizeof(*sg_policy), GFP_KERNEL);
467         if (!sg_policy)
468                 return NULL;
469
470         sg_policy->policy = policy;
471         raw_spin_lock_init(&sg_policy->update_lock);
472         return sg_policy;
473 }
474
475 static void sugov_policy_free(struct sugov_policy *sg_policy)
476 {
477         kfree(sg_policy);
478 }
479
480 static int sugov_kthread_create(struct sugov_policy *sg_policy)
481 {
482         struct task_struct *thread;
483         struct sched_attr attr = {
484                 .size = sizeof(struct sched_attr),
485                 .sched_policy = SCHED_DEADLINE,
486                 .sched_flags = SCHED_FLAG_SUGOV,
487                 .sched_nice = 0,
488                 .sched_priority = 0,
489                 /*
490                  * Fake (unused) bandwidth; workaround to "fix"
491                  * priority inheritance.
492                  */
493                 .sched_runtime  =  1000000,
494                 .sched_deadline = 10000000,
495                 .sched_period   = 10000000,
496         };
497         struct cpufreq_policy *policy = sg_policy->policy;
498         int ret;
499
500         /* kthread only required for slow path */
501         if (policy->fast_switch_enabled)
502                 return 0;
503
504         kthread_init_work(&sg_policy->work, sugov_work);
505         kthread_init_worker(&sg_policy->worker);
506         thread = kthread_create(kthread_worker_fn, &sg_policy->worker,
507                                 "sugov:%d",
508                                 cpumask_first(policy->related_cpus));
509         if (IS_ERR(thread)) {
510                 pr_err("failed to create sugov thread: %ld\n", PTR_ERR(thread));
511                 return PTR_ERR(thread);
512         }
513
514         ret = sched_setattr_nocheck(thread, &attr);
515         if (ret) {
516                 kthread_stop(thread);
517                 pr_warn("%s: failed to set SCHED_DEADLINE\n", __func__);
518                 return ret;
519         }
520
521         sg_policy->thread = thread;
522
523         /* Kthread is bound to all CPUs by default */
524         if (!policy->dvfs_possible_from_any_cpu)
525                 kthread_bind_mask(thread, policy->related_cpus);
526
527         init_irq_work(&sg_policy->irq_work, sugov_irq_work);
528         mutex_init(&sg_policy->work_lock);
529
530         wake_up_process(thread);
531
532         return 0;
533 }
534
535 static void sugov_kthread_stop(struct sugov_policy *sg_policy)
536 {
537         /* kthread only required for slow path */
538         if (sg_policy->policy->fast_switch_enabled)
539                 return;
540
541         kthread_flush_worker(&sg_policy->worker);
542         kthread_stop(sg_policy->thread);
543         mutex_destroy(&sg_policy->work_lock);
544 }
545
546 static struct sugov_tunables *sugov_tunables_alloc(struct sugov_policy *sg_policy)
547 {
548         struct sugov_tunables *tunables;
549
550         tunables = kzalloc(sizeof(*tunables), GFP_KERNEL);
551         if (tunables) {
552                 gov_attr_set_init(&tunables->attr_set, &sg_policy->tunables_hook);
553                 if (!have_governor_per_policy())
554                         global_tunables = tunables;
555         }
556         return tunables;
557 }
558
559 static void sugov_tunables_free(struct sugov_tunables *tunables)
560 {
561         if (!have_governor_per_policy())
562                 global_tunables = NULL;
563
564         kfree(tunables);
565 }
566
567 static int sugov_init(struct cpufreq_policy *policy)
568 {
569         struct sugov_policy *sg_policy;
570         struct sugov_tunables *tunables;
571         int ret = 0;
572
573         /* State should be equivalent to EXIT */
574         if (policy->governor_data)
575                 return -EBUSY;
576
577         cpufreq_enable_fast_switch(policy);
578
579         sg_policy = sugov_policy_alloc(policy);
580         if (!sg_policy) {
581                 ret = -ENOMEM;
582                 goto disable_fast_switch;
583         }
584
585         ret = sugov_kthread_create(sg_policy);
586         if (ret)
587                 goto free_sg_policy;
588
589         mutex_lock(&global_tunables_lock);
590
591         if (global_tunables) {
592                 if (WARN_ON(have_governor_per_policy())) {
593                         ret = -EINVAL;
594                         goto stop_kthread;
595                 }
596                 policy->governor_data = sg_policy;
597                 sg_policy->tunables = global_tunables;
598
599                 gov_attr_set_get(&global_tunables->attr_set, &sg_policy->tunables_hook);
600                 goto out;
601         }
602
603         tunables = sugov_tunables_alloc(sg_policy);
604         if (!tunables) {
605                 ret = -ENOMEM;
606                 goto stop_kthread;
607         }
608
609         tunables->rate_limit_us = cpufreq_policy_transition_delay_us(policy);
610
611         policy->governor_data = sg_policy;
612         sg_policy->tunables = tunables;
613
614         ret = kobject_init_and_add(&tunables->attr_set.kobj, &sugov_tunables_ktype,
615                                    get_governor_parent_kobj(policy), "%s",
616                                    schedutil_gov.name);
617         if (ret)
618                 goto fail;
619
620 out:
621         mutex_unlock(&global_tunables_lock);
622         return 0;
623
624 fail:
625         policy->governor_data = NULL;
626         sugov_tunables_free(tunables);
627
628 stop_kthread:
629         sugov_kthread_stop(sg_policy);
630
631 free_sg_policy:
632         mutex_unlock(&global_tunables_lock);
633
634         sugov_policy_free(sg_policy);
635
636 disable_fast_switch:
637         cpufreq_disable_fast_switch(policy);
638
639         pr_err("initialization failed (error %d)\n", ret);
640         return ret;
641 }
642
643 static void sugov_exit(struct cpufreq_policy *policy)
644 {
645         struct sugov_policy *sg_policy = policy->governor_data;
646         struct sugov_tunables *tunables = sg_policy->tunables;
647         unsigned int count;
648
649         mutex_lock(&global_tunables_lock);
650
651         count = gov_attr_set_put(&tunables->attr_set, &sg_policy->tunables_hook);
652         policy->governor_data = NULL;
653         if (!count)
654                 sugov_tunables_free(tunables);
655
656         mutex_unlock(&global_tunables_lock);
657
658         sugov_kthread_stop(sg_policy);
659         sugov_policy_free(sg_policy);
660         cpufreq_disable_fast_switch(policy);
661 }
662
663 static int sugov_start(struct cpufreq_policy *policy)
664 {
665         struct sugov_policy *sg_policy = policy->governor_data;
666         unsigned int cpu;
667
668         sg_policy->freq_update_delay_ns = sg_policy->tunables->rate_limit_us * NSEC_PER_USEC;
669         sg_policy->last_freq_update_time = 0;
670         sg_policy->next_freq = UINT_MAX;
671         sg_policy->work_in_progress = false;
672         sg_policy->need_freq_update = false;
673         sg_policy->cached_raw_freq = 0;
674
675         for_each_cpu(cpu, policy->cpus) {
676                 struct sugov_cpu *sg_cpu = &per_cpu(sugov_cpu, cpu);
677
678                 memset(sg_cpu, 0, sizeof(*sg_cpu));
679                 sg_cpu->cpu = cpu;
680                 sg_cpu->sg_policy = sg_policy;
681                 sg_cpu->flags = 0;
682                 sg_cpu->iowait_boost_max = policy->cpuinfo.max_freq;
683         }
684
685         for_each_cpu(cpu, policy->cpus) {
686                 struct sugov_cpu *sg_cpu = &per_cpu(sugov_cpu, cpu);
687
688                 cpufreq_add_update_util_hook(cpu, &sg_cpu->update_util,
689                                              policy_is_shared(policy) ?
690                                                         sugov_update_shared :
691                                                         sugov_update_single);
692         }
693         return 0;
694 }
695
696 static void sugov_stop(struct cpufreq_policy *policy)
697 {
698         struct sugov_policy *sg_policy = policy->governor_data;
699         unsigned int cpu;
700
701         for_each_cpu(cpu, policy->cpus)
702                 cpufreq_remove_update_util_hook(cpu);
703
704         synchronize_sched();
705
706         if (!policy->fast_switch_enabled) {
707                 irq_work_sync(&sg_policy->irq_work);
708                 kthread_cancel_work_sync(&sg_policy->work);
709         }
710 }
711
712 static void sugov_limits(struct cpufreq_policy *policy)
713 {
714         struct sugov_policy *sg_policy = policy->governor_data;
715
716         if (!policy->fast_switch_enabled) {
717                 mutex_lock(&sg_policy->work_lock);
718                 cpufreq_policy_apply_limits(policy);
719                 mutex_unlock(&sg_policy->work_lock);
720         }
721
722         sg_policy->need_freq_update = true;
723 }
724
725 static struct cpufreq_governor schedutil_gov = {
726         .name = "schedutil",
727         .owner = THIS_MODULE,
728         .dynamic_switching = true,
729         .init = sugov_init,
730         .exit = sugov_exit,
731         .start = sugov_start,
732         .stop = sugov_stop,
733         .limits = sugov_limits,
734 };
735
736 #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_SCHEDUTIL
737 struct cpufreq_governor *cpufreq_default_governor(void)
738 {
739         return &schedutil_gov;
740 }
741 #endif
742
743 static int __init sugov_register(void)
744 {
745         return cpufreq_register_governor(&schedutil_gov);
746 }
747 fs_initcall(sugov_register);