1 // SPDX-License-Identifier: GPL-2.0
3 * CPUFreq governor based on scheduler-provided CPU utilization data.
5 * Copyright (C) 2016, Intel Corporation
6 * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13 #include <linux/sched/cpufreq.h>
14 #include <trace/events/power.h>
16 #define IOWAIT_BOOST_MIN (SCHED_CAPACITY_SCALE / 8)
18 struct sugov_tunables
{
19 struct gov_attr_set attr_set
;
20 unsigned int rate_limit_us
;
24 struct cpufreq_policy
*policy
;
26 struct sugov_tunables
*tunables
;
27 struct list_head tunables_hook
;
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
;
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
;
44 bool need_freq_update
;
48 struct update_util_data update_util
;
49 struct sugov_policy
*sg_policy
;
52 bool iowait_boost_pending
;
53 unsigned int iowait_boost
;
59 /* The field below is for single-CPU policies only: */
60 #ifdef CONFIG_NO_HZ_COMMON
61 unsigned long saved_idle_calls
;
65 static DEFINE_PER_CPU(struct sugov_cpu
, sugov_cpu
);
67 /************************ Governor internals ***********************/
69 static bool sugov_should_update_freq(struct sugov_policy
*sg_policy
, u64 time
)
74 * Since cpufreq_update_util() is called with rq->lock held for
75 * the @target_cpu, our per-CPU data is fully serialized.
77 * However, drivers cannot in general deal with cross-CPU
78 * requests, so while get_next_freq() will work, our
79 * sugov_update_commit() call may not for the fast switching platforms.
81 * Hence stop here for remote requests if they aren't supported
82 * by the hardware, as calculating the frequency is pointless if
83 * we cannot in fact act on it.
85 * This is needed on the slow switching platforms too to prevent CPUs
86 * going offline from leaving stale IRQ work items behind.
88 if (!cpufreq_this_cpu_can_update(sg_policy
->policy
))
91 if (unlikely(sg_policy
->limits_changed
)) {
92 sg_policy
->limits_changed
= false;
93 sg_policy
->need_freq_update
= true;
97 delta_ns
= time
- sg_policy
->last_freq_update_time
;
99 return delta_ns
>= sg_policy
->freq_update_delay_ns
;
102 static bool sugov_update_next_freq(struct sugov_policy
*sg_policy
, u64 time
,
103 unsigned int next_freq
)
105 if (!sg_policy
->need_freq_update
) {
106 if (sg_policy
->next_freq
== next_freq
)
109 sg_policy
->need_freq_update
= cpufreq_driver_test_flags(CPUFREQ_NEED_UPDATE_LIMITS
);
112 sg_policy
->next_freq
= next_freq
;
113 sg_policy
->last_freq_update_time
= time
;
118 static void sugov_fast_switch(struct sugov_policy
*sg_policy
, u64 time
,
119 unsigned int next_freq
)
121 if (sugov_update_next_freq(sg_policy
, time
, next_freq
))
122 cpufreq_driver_fast_switch(sg_policy
->policy
, next_freq
);
125 static void sugov_deferred_update(struct sugov_policy
*sg_policy
, u64 time
,
126 unsigned int next_freq
)
128 if (!sugov_update_next_freq(sg_policy
, time
, next_freq
))
131 if (!sg_policy
->work_in_progress
) {
132 sg_policy
->work_in_progress
= true;
133 irq_work_queue(&sg_policy
->irq_work
);
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.
143 * If the utilization is frequency-invariant, choose the new frequency to be
144 * proportional to it, that is
146 * next_freq = C * max_freq * util / max
148 * Otherwise, approximate the would-be frequency-invariant utilization by
149 * util_raw * (curr_freq / max_freq) which leads to
151 * next_freq = C * curr_freq * util_raw / max
153 * Take C = 1.25 for the frequency tipping point at (util / max) = 0.8.
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.
159 static unsigned int get_next_freq(struct sugov_policy
*sg_policy
,
160 unsigned long util
, unsigned long max
)
162 struct cpufreq_policy
*policy
= sg_policy
->policy
;
163 unsigned int freq
= arch_scale_freq_invariant() ?
164 policy
->cpuinfo
.max_freq
: policy
->cur
;
166 freq
= map_util_freq(util
, freq
, max
);
168 if (freq
== sg_policy
->cached_raw_freq
&& !sg_policy
->need_freq_update
)
169 return sg_policy
->next_freq
;
171 sg_policy
->cached_raw_freq
= freq
;
172 return cpufreq_driver_resolve_freq(policy
, freq
);
176 * This function computes an effective utilization for the given CPU, to be
177 * used for frequency selection given the linear relation: f = u * f_max.
179 * The scheduler tracks the following metrics:
181 * cpu_util_{cfs,rt,dl,irq}()
184 * Where the cfs,rt and dl util numbers are tracked with the same metric and
185 * synchronized windows and are thus directly comparable.
187 * The cfs,rt,dl utilization are the running times measured with rq->clock_task
188 * which excludes things like IRQ and steal-time. These latter are then accrued
189 * in the irq utilization.
191 * The DL bandwidth number otoh is not a measured metric but a value computed
192 * based on the task model parameters and gives the minimal utilization
193 * required to meet deadlines.
195 unsigned long schedutil_cpu_util(int cpu
, unsigned long util_cfs
,
196 unsigned long max
, enum schedutil_type type
,
197 struct task_struct
*p
)
199 unsigned long dl_util
, util
, irq
;
200 struct rq
*rq
= cpu_rq(cpu
);
202 if (!uclamp_is_used() &&
203 type
== FREQUENCY_UTIL
&& rt_rq_is_runnable(&rq
->rt
)) {
208 * Early check to see if IRQ/steal time saturates the CPU, can be
209 * because of inaccuracies in how we track these -- see
210 * update_irq_load_avg().
212 irq
= cpu_util_irq(rq
);
213 if (unlikely(irq
>= max
))
217 * Because the time spend on RT/DL tasks is visible as 'lost' time to
218 * CFS tasks and we use the same metric to track the effective
219 * utilization (PELT windows are synchronized) we can directly add them
220 * to obtain the CPU's actual utilization.
222 * CFS and RT utilization can be boosted or capped, depending on
223 * utilization clamp constraints requested by currently RUNNABLE
225 * When there are no CFS RUNNABLE tasks, clamps are released and
226 * frequency will be gracefully reduced with the utilization decay.
228 util
= util_cfs
+ cpu_util_rt(rq
);
229 if (type
== FREQUENCY_UTIL
)
230 util
= uclamp_rq_util_with(rq
, util
, p
);
232 dl_util
= cpu_util_dl(rq
);
235 * For frequency selection we do not make cpu_util_dl() a permanent part
236 * of this sum because we want to use cpu_bw_dl() later on, but we need
237 * to check if the CFS+RT+DL sum is saturated (ie. no idle time) such
238 * that we select f_max when there is no idle time.
240 * NOTE: numerical errors or stop class might cause us to not quite hit
241 * saturation when we should -- something for later.
243 if (util
+ dl_util
>= max
)
247 * OTOH, for energy computation we need the estimated running time, so
248 * include util_dl and ignore dl_bw.
250 if (type
== ENERGY_UTIL
)
254 * There is still idle time; further improve the number by using the
255 * irq metric. Because IRQ/steal time is hidden from the task clock we
256 * need to scale the task numbers:
259 * U' = irq + --------- * U
262 util
= scale_irq_capacity(util
, irq
, max
);
266 * Bandwidth required by DEADLINE must always be granted while, for
267 * FAIR and RT, we use blocked utilization of IDLE CPUs as a mechanism
268 * to gracefully reduce the frequency when no tasks show up for longer
271 * Ideally we would like to set bw_dl as min/guaranteed freq and util +
272 * bw_dl as requested freq. However, cpufreq is not yet ready for such
273 * an interface. So, we only do the latter for now.
275 if (type
== FREQUENCY_UTIL
)
276 util
+= cpu_bw_dl(rq
);
278 return min(max
, util
);
281 static unsigned long sugov_get_util(struct sugov_cpu
*sg_cpu
)
283 struct rq
*rq
= cpu_rq(sg_cpu
->cpu
);
284 unsigned long util
= cpu_util_cfs(rq
);
285 unsigned long max
= arch_scale_cpu_capacity(sg_cpu
->cpu
);
288 sg_cpu
->bw_dl
= cpu_bw_dl(rq
);
290 return schedutil_cpu_util(sg_cpu
->cpu
, util
, max
, FREQUENCY_UTIL
, NULL
);
294 * sugov_iowait_reset() - Reset the IO boost status of a CPU.
295 * @sg_cpu: the sugov data for the CPU to boost
296 * @time: the update time from the caller
297 * @set_iowait_boost: true if an IO boost has been requested
299 * The IO wait boost of a task is disabled after a tick since the last update
300 * of a CPU. If a new IO wait boost is requested after more then a tick, then
301 * we enable the boost starting from IOWAIT_BOOST_MIN, which improves energy
302 * efficiency by ignoring sporadic wakeups from IO.
304 static bool sugov_iowait_reset(struct sugov_cpu
*sg_cpu
, u64 time
,
305 bool set_iowait_boost
)
307 s64 delta_ns
= time
- sg_cpu
->last_update
;
309 /* Reset boost only if a tick has elapsed since last request */
310 if (delta_ns
<= TICK_NSEC
)
313 sg_cpu
->iowait_boost
= set_iowait_boost
? IOWAIT_BOOST_MIN
: 0;
314 sg_cpu
->iowait_boost_pending
= set_iowait_boost
;
320 * sugov_iowait_boost() - Updates the IO boost status of a CPU.
321 * @sg_cpu: the sugov data for the CPU to boost
322 * @time: the update time from the caller
323 * @flags: SCHED_CPUFREQ_IOWAIT if the task is waking up after an IO wait
325 * Each time a task wakes up after an IO operation, the CPU utilization can be
326 * boosted to a certain utilization which doubles at each "frequent and
327 * successive" wakeup from IO, ranging from IOWAIT_BOOST_MIN to the utilization
328 * of the maximum OPP.
330 * To keep doubling, an IO boost has to be requested at least once per tick,
331 * otherwise we restart from the utilization of the minimum OPP.
333 static void sugov_iowait_boost(struct sugov_cpu
*sg_cpu
, u64 time
,
336 bool set_iowait_boost
= flags
& SCHED_CPUFREQ_IOWAIT
;
338 /* Reset boost if the CPU appears to have been idle enough */
339 if (sg_cpu
->iowait_boost
&&
340 sugov_iowait_reset(sg_cpu
, time
, set_iowait_boost
))
343 /* Boost only tasks waking up after IO */
344 if (!set_iowait_boost
)
347 /* Ensure boost doubles only one time at each request */
348 if (sg_cpu
->iowait_boost_pending
)
350 sg_cpu
->iowait_boost_pending
= true;
352 /* Double the boost at each request */
353 if (sg_cpu
->iowait_boost
) {
354 sg_cpu
->iowait_boost
=
355 min_t(unsigned int, sg_cpu
->iowait_boost
<< 1, SCHED_CAPACITY_SCALE
);
359 /* First wakeup after IO: start with minimum boost */
360 sg_cpu
->iowait_boost
= IOWAIT_BOOST_MIN
;
364 * sugov_iowait_apply() - Apply the IO boost to a CPU.
365 * @sg_cpu: the sugov data for the cpu to boost
366 * @time: the update time from the caller
367 * @util: the utilization to (eventually) boost
368 * @max: the maximum value the utilization can be boosted to
370 * A CPU running a task which woken up after an IO operation can have its
371 * utilization boosted to speed up the completion of those IO operations.
372 * The IO boost value is increased each time a task wakes up from IO, in
373 * sugov_iowait_apply(), and it's instead decreased by this function,
374 * each time an increase has not been requested (!iowait_boost_pending).
376 * A CPU which also appears to have been idle for at least one tick has also
377 * its IO boost utilization reset.
379 * This mechanism is designed to boost high frequently IO waiting tasks, while
380 * being more conservative on tasks which does sporadic IO operations.
382 static unsigned long sugov_iowait_apply(struct sugov_cpu
*sg_cpu
, u64 time
,
383 unsigned long util
, unsigned long max
)
387 /* No boost currently required */
388 if (!sg_cpu
->iowait_boost
)
391 /* Reset boost if the CPU appears to have been idle enough */
392 if (sugov_iowait_reset(sg_cpu
, time
, false))
395 if (!sg_cpu
->iowait_boost_pending
) {
397 * No boost pending; reduce the boost value.
399 sg_cpu
->iowait_boost
>>= 1;
400 if (sg_cpu
->iowait_boost
< IOWAIT_BOOST_MIN
) {
401 sg_cpu
->iowait_boost
= 0;
406 sg_cpu
->iowait_boost_pending
= false;
409 * @util is already in capacity scale; convert iowait_boost
410 * into the same scale so we can compare.
412 boost
= (sg_cpu
->iowait_boost
* max
) >> SCHED_CAPACITY_SHIFT
;
413 return max(boost
, util
);
416 #ifdef CONFIG_NO_HZ_COMMON
417 static bool sugov_cpu_is_busy(struct sugov_cpu
*sg_cpu
)
419 unsigned long idle_calls
= tick_nohz_get_idle_calls_cpu(sg_cpu
->cpu
);
420 bool ret
= idle_calls
== sg_cpu
->saved_idle_calls
;
422 sg_cpu
->saved_idle_calls
= idle_calls
;
426 static inline bool sugov_cpu_is_busy(struct sugov_cpu
*sg_cpu
) { return false; }
427 #endif /* CONFIG_NO_HZ_COMMON */
430 * Make sugov_should_update_freq() ignore the rate limit when DL
431 * has increased the utilization.
433 static inline void ignore_dl_rate_limit(struct sugov_cpu
*sg_cpu
, struct sugov_policy
*sg_policy
)
435 if (cpu_bw_dl(cpu_rq(sg_cpu
->cpu
)) > sg_cpu
->bw_dl
)
436 sg_policy
->limits_changed
= true;
439 static void sugov_update_single(struct update_util_data
*hook
, u64 time
,
442 struct sugov_cpu
*sg_cpu
= container_of(hook
, struct sugov_cpu
, update_util
);
443 struct sugov_policy
*sg_policy
= sg_cpu
->sg_policy
;
444 unsigned long util
, max
;
446 unsigned int cached_freq
= sg_policy
->cached_raw_freq
;
448 sugov_iowait_boost(sg_cpu
, time
, flags
);
449 sg_cpu
->last_update
= time
;
451 ignore_dl_rate_limit(sg_cpu
, sg_policy
);
453 if (!sugov_should_update_freq(sg_policy
, time
))
456 util
= sugov_get_util(sg_cpu
);
458 util
= sugov_iowait_apply(sg_cpu
, time
, util
, max
);
459 next_f
= get_next_freq(sg_policy
, util
, max
);
461 * Do not reduce the frequency if the CPU has not been idle
462 * recently, as the reduction is likely to be premature then.
464 if (sugov_cpu_is_busy(sg_cpu
) && next_f
< sg_policy
->next_freq
) {
465 next_f
= sg_policy
->next_freq
;
467 /* Restore cached freq as next_freq has changed */
468 sg_policy
->cached_raw_freq
= cached_freq
;
472 * This code runs under rq->lock for the target CPU, so it won't run
473 * concurrently on two different CPUs for the same target and it is not
474 * necessary to acquire the lock in the fast switch case.
476 if (sg_policy
->policy
->fast_switch_enabled
) {
477 sugov_fast_switch(sg_policy
, time
, next_f
);
479 raw_spin_lock(&sg_policy
->update_lock
);
480 sugov_deferred_update(sg_policy
, time
, next_f
);
481 raw_spin_unlock(&sg_policy
->update_lock
);
485 static unsigned int sugov_next_freq_shared(struct sugov_cpu
*sg_cpu
, u64 time
)
487 struct sugov_policy
*sg_policy
= sg_cpu
->sg_policy
;
488 struct cpufreq_policy
*policy
= sg_policy
->policy
;
489 unsigned long util
= 0, max
= 1;
492 for_each_cpu(j
, policy
->cpus
) {
493 struct sugov_cpu
*j_sg_cpu
= &per_cpu(sugov_cpu
, j
);
494 unsigned long j_util
, j_max
;
496 j_util
= sugov_get_util(j_sg_cpu
);
497 j_max
= j_sg_cpu
->max
;
498 j_util
= sugov_iowait_apply(j_sg_cpu
, time
, j_util
, j_max
);
500 if (j_util
* max
> j_max
* util
) {
506 return get_next_freq(sg_policy
, util
, max
);
510 sugov_update_shared(struct update_util_data
*hook
, u64 time
, unsigned int flags
)
512 struct sugov_cpu
*sg_cpu
= container_of(hook
, struct sugov_cpu
, update_util
);
513 struct sugov_policy
*sg_policy
= sg_cpu
->sg_policy
;
516 raw_spin_lock(&sg_policy
->update_lock
);
518 sugov_iowait_boost(sg_cpu
, time
, flags
);
519 sg_cpu
->last_update
= time
;
521 ignore_dl_rate_limit(sg_cpu
, sg_policy
);
523 if (sugov_should_update_freq(sg_policy
, time
)) {
524 next_f
= sugov_next_freq_shared(sg_cpu
, time
);
526 if (sg_policy
->policy
->fast_switch_enabled
)
527 sugov_fast_switch(sg_policy
, time
, next_f
);
529 sugov_deferred_update(sg_policy
, time
, next_f
);
532 raw_spin_unlock(&sg_policy
->update_lock
);
535 static void sugov_work(struct kthread_work
*work
)
537 struct sugov_policy
*sg_policy
= container_of(work
, struct sugov_policy
, work
);
542 * Hold sg_policy->update_lock shortly to handle the case where:
543 * incase sg_policy->next_freq is read here, and then updated by
544 * sugov_deferred_update() just before work_in_progress is set to false
545 * here, we may miss queueing the new update.
547 * Note: If a work was queued after the update_lock is released,
548 * sugov_work() will just be called again by kthread_work code; and the
549 * request will be proceed before the sugov thread sleeps.
551 raw_spin_lock_irqsave(&sg_policy
->update_lock
, flags
);
552 freq
= sg_policy
->next_freq
;
553 sg_policy
->work_in_progress
= false;
554 raw_spin_unlock_irqrestore(&sg_policy
->update_lock
, flags
);
556 mutex_lock(&sg_policy
->work_lock
);
557 __cpufreq_driver_target(sg_policy
->policy
, freq
, CPUFREQ_RELATION_L
);
558 mutex_unlock(&sg_policy
->work_lock
);
561 static void sugov_irq_work(struct irq_work
*irq_work
)
563 struct sugov_policy
*sg_policy
;
565 sg_policy
= container_of(irq_work
, struct sugov_policy
, irq_work
);
567 kthread_queue_work(&sg_policy
->worker
, &sg_policy
->work
);
570 /************************** sysfs interface ************************/
572 static struct sugov_tunables
*global_tunables
;
573 static DEFINE_MUTEX(global_tunables_lock
);
575 static inline struct sugov_tunables
*to_sugov_tunables(struct gov_attr_set
*attr_set
)
577 return container_of(attr_set
, struct sugov_tunables
, attr_set
);
580 static ssize_t
rate_limit_us_show(struct gov_attr_set
*attr_set
, char *buf
)
582 struct sugov_tunables
*tunables
= to_sugov_tunables(attr_set
);
584 return sprintf(buf
, "%u\n", tunables
->rate_limit_us
);
588 rate_limit_us_store(struct gov_attr_set
*attr_set
, const char *buf
, size_t count
)
590 struct sugov_tunables
*tunables
= to_sugov_tunables(attr_set
);
591 struct sugov_policy
*sg_policy
;
592 unsigned int rate_limit_us
;
594 if (kstrtouint(buf
, 10, &rate_limit_us
))
597 tunables
->rate_limit_us
= rate_limit_us
;
599 list_for_each_entry(sg_policy
, &attr_set
->policy_list
, tunables_hook
)
600 sg_policy
->freq_update_delay_ns
= rate_limit_us
* NSEC_PER_USEC
;
605 static struct governor_attr rate_limit_us
= __ATTR_RW(rate_limit_us
);
607 static struct attribute
*sugov_attrs
[] = {
611 ATTRIBUTE_GROUPS(sugov
);
613 static struct kobj_type sugov_tunables_ktype
= {
614 .default_groups
= sugov_groups
,
615 .sysfs_ops
= &governor_sysfs_ops
,
618 /********************** cpufreq governor interface *********************/
620 struct cpufreq_governor schedutil_gov
;
622 static struct sugov_policy
*sugov_policy_alloc(struct cpufreq_policy
*policy
)
624 struct sugov_policy
*sg_policy
;
626 sg_policy
= kzalloc(sizeof(*sg_policy
), GFP_KERNEL
);
630 sg_policy
->policy
= policy
;
631 raw_spin_lock_init(&sg_policy
->update_lock
);
635 static void sugov_policy_free(struct sugov_policy
*sg_policy
)
640 static int sugov_kthread_create(struct sugov_policy
*sg_policy
)
642 struct task_struct
*thread
;
643 struct sched_attr attr
= {
644 .size
= sizeof(struct sched_attr
),
645 .sched_policy
= SCHED_DEADLINE
,
646 .sched_flags
= SCHED_FLAG_SUGOV
,
650 * Fake (unused) bandwidth; workaround to "fix"
651 * priority inheritance.
653 .sched_runtime
= 1000000,
654 .sched_deadline
= 10000000,
655 .sched_period
= 10000000,
657 struct cpufreq_policy
*policy
= sg_policy
->policy
;
660 /* kthread only required for slow path */
661 if (policy
->fast_switch_enabled
)
664 kthread_init_work(&sg_policy
->work
, sugov_work
);
665 kthread_init_worker(&sg_policy
->worker
);
666 thread
= kthread_create(kthread_worker_fn
, &sg_policy
->worker
,
668 cpumask_first(policy
->related_cpus
));
669 if (IS_ERR(thread
)) {
670 pr_err("failed to create sugov thread: %ld\n", PTR_ERR(thread
));
671 return PTR_ERR(thread
);
674 ret
= sched_setattr_nocheck(thread
, &attr
);
676 kthread_stop(thread
);
677 pr_warn("%s: failed to set SCHED_DEADLINE\n", __func__
);
681 sg_policy
->thread
= thread
;
682 kthread_bind_mask(thread
, policy
->related_cpus
);
683 init_irq_work(&sg_policy
->irq_work
, sugov_irq_work
);
684 mutex_init(&sg_policy
->work_lock
);
686 wake_up_process(thread
);
691 static void sugov_kthread_stop(struct sugov_policy
*sg_policy
)
693 /* kthread only required for slow path */
694 if (sg_policy
->policy
->fast_switch_enabled
)
697 kthread_flush_worker(&sg_policy
->worker
);
698 kthread_stop(sg_policy
->thread
);
699 mutex_destroy(&sg_policy
->work_lock
);
702 static struct sugov_tunables
*sugov_tunables_alloc(struct sugov_policy
*sg_policy
)
704 struct sugov_tunables
*tunables
;
706 tunables
= kzalloc(sizeof(*tunables
), GFP_KERNEL
);
708 gov_attr_set_init(&tunables
->attr_set
, &sg_policy
->tunables_hook
);
709 if (!have_governor_per_policy())
710 global_tunables
= tunables
;
715 static void sugov_tunables_free(struct sugov_tunables
*tunables
)
717 if (!have_governor_per_policy())
718 global_tunables
= NULL
;
723 static int sugov_init(struct cpufreq_policy
*policy
)
725 struct sugov_policy
*sg_policy
;
726 struct sugov_tunables
*tunables
;
729 /* State should be equivalent to EXIT */
730 if (policy
->governor_data
)
733 cpufreq_enable_fast_switch(policy
);
735 sg_policy
= sugov_policy_alloc(policy
);
738 goto disable_fast_switch
;
741 ret
= sugov_kthread_create(sg_policy
);
745 mutex_lock(&global_tunables_lock
);
747 if (global_tunables
) {
748 if (WARN_ON(have_governor_per_policy())) {
752 policy
->governor_data
= sg_policy
;
753 sg_policy
->tunables
= global_tunables
;
755 gov_attr_set_get(&global_tunables
->attr_set
, &sg_policy
->tunables_hook
);
759 tunables
= sugov_tunables_alloc(sg_policy
);
765 tunables
->rate_limit_us
= cpufreq_policy_transition_delay_us(policy
);
767 policy
->governor_data
= sg_policy
;
768 sg_policy
->tunables
= tunables
;
770 ret
= kobject_init_and_add(&tunables
->attr_set
.kobj
, &sugov_tunables_ktype
,
771 get_governor_parent_kobj(policy
), "%s",
777 mutex_unlock(&global_tunables_lock
);
781 kobject_put(&tunables
->attr_set
.kobj
);
782 policy
->governor_data
= NULL
;
783 sugov_tunables_free(tunables
);
786 sugov_kthread_stop(sg_policy
);
787 mutex_unlock(&global_tunables_lock
);
790 sugov_policy_free(sg_policy
);
793 cpufreq_disable_fast_switch(policy
);
795 pr_err("initialization failed (error %d)\n", ret
);
799 static void sugov_exit(struct cpufreq_policy
*policy
)
801 struct sugov_policy
*sg_policy
= policy
->governor_data
;
802 struct sugov_tunables
*tunables
= sg_policy
->tunables
;
805 mutex_lock(&global_tunables_lock
);
807 count
= gov_attr_set_put(&tunables
->attr_set
, &sg_policy
->tunables_hook
);
808 policy
->governor_data
= NULL
;
810 sugov_tunables_free(tunables
);
812 mutex_unlock(&global_tunables_lock
);
814 sugov_kthread_stop(sg_policy
);
815 sugov_policy_free(sg_policy
);
816 cpufreq_disable_fast_switch(policy
);
819 static int sugov_start(struct cpufreq_policy
*policy
)
821 struct sugov_policy
*sg_policy
= policy
->governor_data
;
824 sg_policy
->freq_update_delay_ns
= sg_policy
->tunables
->rate_limit_us
* NSEC_PER_USEC
;
825 sg_policy
->last_freq_update_time
= 0;
826 sg_policy
->next_freq
= 0;
827 sg_policy
->work_in_progress
= false;
828 sg_policy
->limits_changed
= false;
829 sg_policy
->cached_raw_freq
= 0;
831 sg_policy
->need_freq_update
= cpufreq_driver_test_flags(CPUFREQ_NEED_UPDATE_LIMITS
);
833 for_each_cpu(cpu
, policy
->cpus
) {
834 struct sugov_cpu
*sg_cpu
= &per_cpu(sugov_cpu
, cpu
);
836 memset(sg_cpu
, 0, sizeof(*sg_cpu
));
838 sg_cpu
->sg_policy
= sg_policy
;
841 for_each_cpu(cpu
, policy
->cpus
) {
842 struct sugov_cpu
*sg_cpu
= &per_cpu(sugov_cpu
, cpu
);
844 cpufreq_add_update_util_hook(cpu
, &sg_cpu
->update_util
,
845 policy_is_shared(policy
) ?
846 sugov_update_shared
:
847 sugov_update_single
);
852 static void sugov_stop(struct cpufreq_policy
*policy
)
854 struct sugov_policy
*sg_policy
= policy
->governor_data
;
857 for_each_cpu(cpu
, policy
->cpus
)
858 cpufreq_remove_update_util_hook(cpu
);
862 if (!policy
->fast_switch_enabled
) {
863 irq_work_sync(&sg_policy
->irq_work
);
864 kthread_cancel_work_sync(&sg_policy
->work
);
868 static void sugov_limits(struct cpufreq_policy
*policy
)
870 struct sugov_policy
*sg_policy
= policy
->governor_data
;
872 if (!policy
->fast_switch_enabled
) {
873 mutex_lock(&sg_policy
->work_lock
);
874 cpufreq_policy_apply_limits(policy
);
875 mutex_unlock(&sg_policy
->work_lock
);
878 sg_policy
->limits_changed
= true;
881 struct cpufreq_governor schedutil_gov
= {
883 .owner
= THIS_MODULE
,
884 .flags
= CPUFREQ_GOV_DYNAMIC_SWITCHING
,
887 .start
= sugov_start
,
889 .limits
= sugov_limits
,
892 #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_SCHEDUTIL
893 struct cpufreq_governor
*cpufreq_default_governor(void)
895 return &schedutil_gov
;
899 cpufreq_governor_init(schedutil_gov
);
901 #ifdef CONFIG_ENERGY_MODEL
902 extern bool sched_energy_update
;
903 extern struct mutex sched_energy_mutex
;
905 static void rebuild_sd_workfn(struct work_struct
*work
)
907 mutex_lock(&sched_energy_mutex
);
908 sched_energy_update
= true;
909 rebuild_sched_domains();
910 sched_energy_update
= false;
911 mutex_unlock(&sched_energy_mutex
);
913 static DECLARE_WORK(rebuild_sd_work
, rebuild_sd_workfn
);
916 * EAS shouldn't be attempted without sugov, so rebuild the sched_domains
917 * on governor changes to make sure the scheduler knows about it.
919 void sched_cpufreq_governor_change(struct cpufreq_policy
*policy
,
920 struct cpufreq_governor
*old_gov
)
922 if (old_gov
== &schedutil_gov
|| policy
->governor
== &schedutil_gov
) {
924 * When called from the cpufreq_register_driver() path, the
925 * cpu_hotplug_lock is already held, so use a work item to
926 * avoid nested locking in rebuild_sched_domains().
928 schedule_work(&rebuild_sd_work
);