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1 : : // SPDX-License-Identifier: GPL-2.0-only
2 : : /*
3 : : * drivers/cpufreq/cpufreq_governor.c
4 : : *
5 : : * CPUFREQ governors common code
6 : : *
7 : : * Copyright (C) 2001 Russell King
8 : : * (C) 2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
9 : : * (C) 2003 Jun Nakajima <jun.nakajima@intel.com>
10 : : * (C) 2009 Alexander Clouter <alex@digriz.org.uk>
11 : : * (c) 2012 Viresh Kumar <viresh.kumar@linaro.org>
12 : : */
13 : :
14 : : #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15 : :
16 : : #include <linux/export.h>
17 : : #include <linux/kernel_stat.h>
18 : : #include <linux/slab.h>
19 : :
20 : : #include "cpufreq_governor.h"
21 : :
22 : : #define CPUFREQ_DBS_MIN_SAMPLING_INTERVAL (2 * TICK_NSEC / NSEC_PER_USEC)
23 : :
24 : : static DEFINE_PER_CPU(struct cpu_dbs_info, cpu_dbs);
25 : :
26 : : static DEFINE_MUTEX(gov_dbs_data_mutex);
27 : :
28 : : /* Common sysfs tunables */
29 : : /**
30 : : * store_sampling_rate - update sampling rate effective immediately if needed.
31 : : *
32 : : * If new rate is smaller than the old, simply updating
33 : : * dbs.sampling_rate might not be appropriate. For example, if the
34 : : * original sampling_rate was 1 second and the requested new sampling rate is 10
35 : : * ms because the user needs immediate reaction from ondemand governor, but not
36 : : * sure if higher frequency will be required or not, then, the governor may
37 : : * change the sampling rate too late; up to 1 second later. Thus, if we are
38 : : * reducing the sampling rate, we need to make the new value effective
39 : : * immediately.
40 : : *
41 : : * This must be called with dbs_data->mutex held, otherwise traversing
42 : : * policy_dbs_list isn't safe.
43 : : */
44 : 2 : ssize_t store_sampling_rate(struct gov_attr_set *attr_set, const char *buf,
45 : : size_t count)
46 : : {
47 : : struct dbs_data *dbs_data = to_dbs_data(attr_set);
48 : : struct policy_dbs_info *policy_dbs;
49 : : unsigned int sampling_interval;
50 : : int ret;
51 : :
52 : 2 : ret = sscanf(buf, "%u", &sampling_interval);
53 : 2 : if (ret != 1 || sampling_interval < CPUFREQ_DBS_MIN_SAMPLING_INTERVAL)
54 : : return -EINVAL;
55 : :
56 : 2 : dbs_data->sampling_rate = sampling_interval;
57 : :
58 : : /*
59 : : * We are operating under dbs_data->mutex and so the list and its
60 : : * entries can't be freed concurrently.
61 : : */
62 : 2 : list_for_each_entry(policy_dbs, &attr_set->policy_list, list) {
63 : 2 : mutex_lock(&policy_dbs->update_mutex);
64 : : /*
65 : : * On 32-bit architectures this may race with the
66 : : * sample_delay_ns read in dbs_update_util_handler(), but that
67 : : * really doesn't matter. If the read returns a value that's
68 : : * too big, the sample will be skipped, but the next invocation
69 : : * of dbs_update_util_handler() (when the update has been
70 : : * completed) will take a sample.
71 : : *
72 : : * If this runs in parallel with dbs_work_handler(), we may end
73 : : * up overwriting the sample_delay_ns value that it has just
74 : : * written, but it will be corrected next time a sample is
75 : : * taken, so it shouldn't be significant.
76 : : */
77 : : gov_update_sample_delay(policy_dbs, 0);
78 : 2 : mutex_unlock(&policy_dbs->update_mutex);
79 : : }
80 : :
81 : 2 : return count;
82 : : }
83 : : EXPORT_SYMBOL_GPL(store_sampling_rate);
84 : :
85 : : /**
86 : : * gov_update_cpu_data - Update CPU load data.
87 : : * @dbs_data: Top-level governor data pointer.
88 : : *
89 : : * Update CPU load data for all CPUs in the domain governed by @dbs_data
90 : : * (that may be a single policy or a bunch of them if governor tunables are
91 : : * system-wide).
92 : : *
93 : : * Call under the @dbs_data mutex.
94 : : */
95 : 0 : void gov_update_cpu_data(struct dbs_data *dbs_data)
96 : : {
97 : : struct policy_dbs_info *policy_dbs;
98 : :
99 : 0 : list_for_each_entry(policy_dbs, &dbs_data->attr_set.policy_list, list) {
100 : : unsigned int j;
101 : :
102 : 0 : for_each_cpu(j, policy_dbs->policy->cpus) {
103 : 0 : struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j);
104 : :
105 : 0 : j_cdbs->prev_cpu_idle = get_cpu_idle_time(j, &j_cdbs->prev_update_time,
106 : 0 : dbs_data->io_is_busy);
107 : 0 : if (dbs_data->ignore_nice_load)
108 : 0 : j_cdbs->prev_cpu_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE];
109 : : }
110 : : }
111 : 0 : }
112 : : EXPORT_SYMBOL_GPL(gov_update_cpu_data);
113 : :
114 : 2 : unsigned int dbs_update(struct cpufreq_policy *policy)
115 : : {
116 : 2 : struct policy_dbs_info *policy_dbs = policy->governor_data;
117 : 2 : struct dbs_data *dbs_data = policy_dbs->dbs_data;
118 : 2 : unsigned int ignore_nice = dbs_data->ignore_nice_load;
119 : : unsigned int max_load = 0, idle_periods = UINT_MAX;
120 : : unsigned int sampling_rate, io_busy, j;
121 : :
122 : : /*
123 : : * Sometimes governors may use an additional multiplier to increase
124 : : * sample delays temporarily. Apply that multiplier to sampling_rate
125 : : * so as to keep the wake-up-from-idle detection logic a bit
126 : : * conservative.
127 : : */
128 : 2 : sampling_rate = dbs_data->sampling_rate * policy_dbs->rate_mult;
129 : : /*
130 : : * For the purpose of ondemand, waiting for disk IO is an indication
131 : : * that you're performance critical, and not that the system is actually
132 : : * idle, so do not add the iowait time to the CPU idle time then.
133 : : */
134 : 2 : io_busy = dbs_data->io_is_busy;
135 : :
136 : : /* Get Absolute Load */
137 : 2 : for_each_cpu(j, policy->cpus) {
138 : 2 : struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j);
139 : : u64 update_time, cur_idle_time;
140 : : unsigned int idle_time, time_elapsed;
141 : : unsigned int load;
142 : :
143 : 2 : cur_idle_time = get_cpu_idle_time(j, &update_time, io_busy);
144 : :
145 : 2 : time_elapsed = update_time - j_cdbs->prev_update_time;
146 : 2 : j_cdbs->prev_update_time = update_time;
147 : :
148 : 2 : idle_time = cur_idle_time - j_cdbs->prev_cpu_idle;
149 : 2 : j_cdbs->prev_cpu_idle = cur_idle_time;
150 : :
151 : 2 : if (ignore_nice) {
152 : 0 : u64 cur_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE];
153 : :
154 : 0 : idle_time += div_u64(cur_nice - j_cdbs->prev_cpu_nice, NSEC_PER_USEC);
155 : 0 : j_cdbs->prev_cpu_nice = cur_nice;
156 : : }
157 : :
158 : 2 : if (unlikely(!time_elapsed)) {
159 : : /*
160 : : * That can only happen when this function is called
161 : : * twice in a row with a very short interval between the
162 : : * calls, so the previous load value can be used then.
163 : : */
164 : 0 : load = j_cdbs->prev_load;
165 : 2 : } else if (unlikely((int)idle_time > 2 * sampling_rate &&
166 : : j_cdbs->prev_load)) {
167 : : /*
168 : : * If the CPU had gone completely idle and a task has
169 : : * just woken up on this CPU now, it would be unfair to
170 : : * calculate 'load' the usual way for this elapsed
171 : : * time-window, because it would show near-zero load,
172 : : * irrespective of how CPU intensive that task actually
173 : : * was. This is undesirable for latency-sensitive bursty
174 : : * workloads.
175 : : *
176 : : * To avoid this, reuse the 'load' from the previous
177 : : * time-window and give this task a chance to start with
178 : : * a reasonably high CPU frequency. However, that
179 : : * shouldn't be over-done, lest we get stuck at a high
180 : : * load (high frequency) for too long, even when the
181 : : * current system load has actually dropped down, so
182 : : * clear prev_load to guarantee that the load will be
183 : : * computed again next time.
184 : : *
185 : : * Detecting this situation is easy: an unusually large
186 : : * 'idle_time' (as compared to the sampling rate)
187 : : * indicates this scenario.
188 : : */
189 : : load = j_cdbs->prev_load;
190 : 2 : j_cdbs->prev_load = 0;
191 : : } else {
192 : 2 : if (time_elapsed >= idle_time) {
193 : 2 : load = 100 * (time_elapsed - idle_time) / time_elapsed;
194 : : } else {
195 : : /*
196 : : * That can happen if idle_time is returned by
197 : : * get_cpu_idle_time_jiffy(). In that case
198 : : * idle_time is roughly equal to the difference
199 : : * between time_elapsed and "busy time" obtained
200 : : * from CPU statistics. Then, the "busy time"
201 : : * can end up being greater than time_elapsed
202 : : * (for example, if jiffies_64 and the CPU
203 : : * statistics are updated by different CPUs),
204 : : * so idle_time may in fact be negative. That
205 : : * means, though, that the CPU was busy all
206 : : * the time (on the rough average) during the
207 : : * last sampling interval and 100 can be
208 : : * returned as the load.
209 : : */
210 : 2 : load = (int)idle_time < 0 ? 100 : 0;
211 : : }
212 : 2 : j_cdbs->prev_load = load;
213 : : }
214 : :
215 : 2 : if (unlikely((int)idle_time > 2 * sampling_rate)) {
216 : 2 : unsigned int periods = idle_time / sampling_rate;
217 : :
218 : 2 : if (periods < idle_periods)
219 : : idle_periods = periods;
220 : : }
221 : :
222 : 2 : if (load > max_load)
223 : : max_load = load;
224 : : }
225 : :
226 : 2 : policy_dbs->idle_periods = idle_periods;
227 : :
228 : 2 : return max_load;
229 : : }
230 : : EXPORT_SYMBOL_GPL(dbs_update);
231 : :
232 : 2 : static void dbs_work_handler(struct work_struct *work)
233 : : {
234 : : struct policy_dbs_info *policy_dbs;
235 : : struct cpufreq_policy *policy;
236 : : struct dbs_governor *gov;
237 : :
238 : : policy_dbs = container_of(work, struct policy_dbs_info, work);
239 : 2 : policy = policy_dbs->policy;
240 : : gov = dbs_governor_of(policy);
241 : :
242 : : /*
243 : : * Make sure cpufreq_governor_limits() isn't evaluating load or the
244 : : * ondemand governor isn't updating the sampling rate in parallel.
245 : : */
246 : 2 : mutex_lock(&policy_dbs->update_mutex);
247 : 2 : gov_update_sample_delay(policy_dbs, gov->gov_dbs_update(policy));
248 : 2 : mutex_unlock(&policy_dbs->update_mutex);
249 : :
250 : : /* Allow the utilization update handler to queue up more work. */
251 : : atomic_set(&policy_dbs->work_count, 0);
252 : : /*
253 : : * If the update below is reordered with respect to the sample delay
254 : : * modification, the utilization update handler may end up using a stale
255 : : * sample delay value.
256 : : */
257 : 2 : smp_wmb();
258 : 2 : policy_dbs->work_in_progress = false;
259 : 2 : }
260 : :
261 : 2 : static void dbs_irq_work(struct irq_work *irq_work)
262 : : {
263 : : struct policy_dbs_info *policy_dbs;
264 : :
265 : : policy_dbs = container_of(irq_work, struct policy_dbs_info, irq_work);
266 : 2 : schedule_work_on(smp_processor_id(), &policy_dbs->work);
267 : 2 : }
268 : :
269 : 2 : static void dbs_update_util_handler(struct update_util_data *data, u64 time,
270 : : unsigned int flags)
271 : : {
272 : : struct cpu_dbs_info *cdbs = container_of(data, struct cpu_dbs_info, update_util);
273 : 2 : struct policy_dbs_info *policy_dbs = cdbs->policy_dbs;
274 : : u64 delta_ns, lst;
275 : :
276 : 2 : if (!cpufreq_this_cpu_can_update(policy_dbs->policy))
277 : : return;
278 : :
279 : : /*
280 : : * The work may not be allowed to be queued up right now.
281 : : * Possible reasons:
282 : : * - Work has already been queued up or is in progress.
283 : : * - It is too early (too little time from the previous sample).
284 : : */
285 : 2 : if (policy_dbs->work_in_progress)
286 : : return;
287 : :
288 : : /*
289 : : * If the reads below are reordered before the check above, the value
290 : : * of sample_delay_ns used in the computation may be stale.
291 : : */
292 : 2 : smp_rmb();
293 : : lst = READ_ONCE(policy_dbs->last_sample_time);
294 : 2 : delta_ns = time - lst;
295 : 2 : if ((s64)delta_ns < policy_dbs->sample_delay_ns)
296 : : return;
297 : :
298 : : /*
299 : : * If the policy is not shared, the irq_work may be queued up right away
300 : : * at this point. Otherwise, we need to ensure that only one of the
301 : : * CPUs sharing the policy will do that.
302 : : */
303 : 2 : if (policy_dbs->is_shared) {
304 : 2 : if (!atomic_add_unless(&policy_dbs->work_count, 1, 1))
305 : : return;
306 : :
307 : : /*
308 : : * If another CPU updated last_sample_time in the meantime, we
309 : : * shouldn't be here, so clear the work counter and bail out.
310 : : */
311 : 2 : if (unlikely(lst != READ_ONCE(policy_dbs->last_sample_time))) {
312 : : atomic_set(&policy_dbs->work_count, 0);
313 : 0 : return;
314 : : }
315 : : }
316 : :
317 : 2 : policy_dbs->last_sample_time = time;
318 : 2 : policy_dbs->work_in_progress = true;
319 : 2 : irq_work_queue(&policy_dbs->irq_work);
320 : : }
321 : :
322 : 2 : static void gov_set_update_util(struct policy_dbs_info *policy_dbs,
323 : : unsigned int delay_us)
324 : : {
325 : 2 : struct cpufreq_policy *policy = policy_dbs->policy;
326 : : int cpu;
327 : :
328 : : gov_update_sample_delay(policy_dbs, delay_us);
329 : 2 : policy_dbs->last_sample_time = 0;
330 : :
331 : 2 : for_each_cpu(cpu, policy->cpus) {
332 : 2 : struct cpu_dbs_info *cdbs = &per_cpu(cpu_dbs, cpu);
333 : :
334 : 2 : cpufreq_add_update_util_hook(cpu, &cdbs->update_util,
335 : : dbs_update_util_handler);
336 : : }
337 : 2 : }
338 : :
339 : 0 : static inline void gov_clear_update_util(struct cpufreq_policy *policy)
340 : : {
341 : : int i;
342 : :
343 : 0 : for_each_cpu(i, policy->cpus)
344 : 0 : cpufreq_remove_update_util_hook(i);
345 : :
346 : 0 : synchronize_rcu();
347 : 0 : }
348 : :
349 : 2 : static struct policy_dbs_info *alloc_policy_dbs_info(struct cpufreq_policy *policy,
350 : : struct dbs_governor *gov)
351 : : {
352 : : struct policy_dbs_info *policy_dbs;
353 : : int j;
354 : :
355 : : /* Allocate memory for per-policy governor data. */
356 : 2 : policy_dbs = gov->alloc();
357 : 2 : if (!policy_dbs)
358 : : return NULL;
359 : :
360 : 2 : policy_dbs->policy = policy;
361 : 2 : mutex_init(&policy_dbs->update_mutex);
362 : : atomic_set(&policy_dbs->work_count, 0);
363 : : init_irq_work(&policy_dbs->irq_work, dbs_irq_work);
364 : 2 : INIT_WORK(&policy_dbs->work, dbs_work_handler);
365 : :
366 : : /* Set policy_dbs for all CPUs, online+offline */
367 : 2 : for_each_cpu(j, policy->related_cpus) {
368 : 2 : struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j);
369 : :
370 : 2 : j_cdbs->policy_dbs = policy_dbs;
371 : : }
372 : : return policy_dbs;
373 : : }
374 : :
375 : 0 : static void free_policy_dbs_info(struct policy_dbs_info *policy_dbs,
376 : : struct dbs_governor *gov)
377 : : {
378 : : int j;
379 : :
380 : : mutex_destroy(&policy_dbs->update_mutex);
381 : :
382 : 0 : for_each_cpu(j, policy_dbs->policy->related_cpus) {
383 : 0 : struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j);
384 : :
385 : 0 : j_cdbs->policy_dbs = NULL;
386 : 0 : j_cdbs->update_util.func = NULL;
387 : : }
388 : 0 : gov->free(policy_dbs);
389 : 0 : }
390 : :
391 : 2 : int cpufreq_dbs_governor_init(struct cpufreq_policy *policy)
392 : : {
393 : : struct dbs_governor *gov = dbs_governor_of(policy);
394 : : struct dbs_data *dbs_data;
395 : : struct policy_dbs_info *policy_dbs;
396 : : int ret = 0;
397 : :
398 : : /* State should be equivalent to EXIT */
399 : 2 : if (policy->governor_data)
400 : : return -EBUSY;
401 : :
402 : 2 : policy_dbs = alloc_policy_dbs_info(policy, gov);
403 : 2 : if (!policy_dbs)
404 : : return -ENOMEM;
405 : :
406 : : /* Protect gov->gdbs_data against concurrent updates. */
407 : 2 : mutex_lock(&gov_dbs_data_mutex);
408 : :
409 : 2 : dbs_data = gov->gdbs_data;
410 : 2 : if (dbs_data) {
411 : 0 : if (WARN_ON(have_governor_per_policy())) {
412 : : ret = -EINVAL;
413 : : goto free_policy_dbs_info;
414 : : }
415 : 0 : policy_dbs->dbs_data = dbs_data;
416 : 0 : policy->governor_data = policy_dbs;
417 : :
418 : 0 : gov_attr_set_get(&dbs_data->attr_set, &policy_dbs->list);
419 : 0 : goto out;
420 : : }
421 : :
422 : 2 : dbs_data = kzalloc(sizeof(*dbs_data), GFP_KERNEL);
423 : 2 : if (!dbs_data) {
424 : : ret = -ENOMEM;
425 : : goto free_policy_dbs_info;
426 : : }
427 : :
428 : 2 : gov_attr_set_init(&dbs_data->attr_set, &policy_dbs->list);
429 : :
430 : 2 : ret = gov->init(dbs_data);
431 : 2 : if (ret)
432 : : goto free_policy_dbs_info;
433 : :
434 : : /*
435 : : * The sampling interval should not be less than the transition latency
436 : : * of the CPU and it also cannot be too small for dbs_update() to work
437 : : * correctly.
438 : : */
439 : 2 : dbs_data->sampling_rate = max_t(unsigned int,
440 : : CPUFREQ_DBS_MIN_SAMPLING_INTERVAL,
441 : : cpufreq_policy_transition_delay_us(policy));
442 : :
443 : 2 : if (!have_governor_per_policy())
444 : 2 : gov->gdbs_data = dbs_data;
445 : :
446 : 2 : policy_dbs->dbs_data = dbs_data;
447 : 2 : policy->governor_data = policy_dbs;
448 : :
449 : 2 : gov->kobj_type.sysfs_ops = &governor_sysfs_ops;
450 : 2 : ret = kobject_init_and_add(&dbs_data->attr_set.kobj, &gov->kobj_type,
451 : : get_governor_parent_kobj(policy),
452 : 2 : "%s", gov->gov.name);
453 : 2 : if (!ret)
454 : : goto out;
455 : :
456 : : /* Failure, so roll back. */
457 : 0 : pr_err("initialization failed (dbs_data kobject init error %d)\n", ret);
458 : :
459 : 0 : kobject_put(&dbs_data->attr_set.kobj);
460 : :
461 : 0 : policy->governor_data = NULL;
462 : :
463 : 0 : if (!have_governor_per_policy())
464 : 0 : gov->gdbs_data = NULL;
465 : 0 : gov->exit(dbs_data);
466 : 0 : kfree(dbs_data);
467 : :
468 : : free_policy_dbs_info:
469 : 0 : free_policy_dbs_info(policy_dbs, gov);
470 : :
471 : : out:
472 : 2 : mutex_unlock(&gov_dbs_data_mutex);
473 : 2 : return ret;
474 : : }
475 : : EXPORT_SYMBOL_GPL(cpufreq_dbs_governor_init);
476 : :
477 : 0 : void cpufreq_dbs_governor_exit(struct cpufreq_policy *policy)
478 : : {
479 : : struct dbs_governor *gov = dbs_governor_of(policy);
480 : 0 : struct policy_dbs_info *policy_dbs = policy->governor_data;
481 : 0 : struct dbs_data *dbs_data = policy_dbs->dbs_data;
482 : : unsigned int count;
483 : :
484 : : /* Protect gov->gdbs_data against concurrent updates. */
485 : 0 : mutex_lock(&gov_dbs_data_mutex);
486 : :
487 : 0 : count = gov_attr_set_put(&dbs_data->attr_set, &policy_dbs->list);
488 : :
489 : 0 : policy->governor_data = NULL;
490 : :
491 : 0 : if (!count) {
492 : 0 : if (!have_governor_per_policy())
493 : 0 : gov->gdbs_data = NULL;
494 : :
495 : 0 : gov->exit(dbs_data);
496 : 0 : kfree(dbs_data);
497 : : }
498 : :
499 : 0 : free_policy_dbs_info(policy_dbs, gov);
500 : :
501 : 0 : mutex_unlock(&gov_dbs_data_mutex);
502 : 0 : }
503 : : EXPORT_SYMBOL_GPL(cpufreq_dbs_governor_exit);
504 : :
505 : 2 : int cpufreq_dbs_governor_start(struct cpufreq_policy *policy)
506 : : {
507 : : struct dbs_governor *gov = dbs_governor_of(policy);
508 : 2 : struct policy_dbs_info *policy_dbs = policy->governor_data;
509 : 2 : struct dbs_data *dbs_data = policy_dbs->dbs_data;
510 : : unsigned int sampling_rate, ignore_nice, j;
511 : : unsigned int io_busy;
512 : :
513 : 2 : if (!policy->cur)
514 : : return -EINVAL;
515 : :
516 : 2 : policy_dbs->is_shared = policy_is_shared(policy);
517 : 2 : policy_dbs->rate_mult = 1;
518 : :
519 : 2 : sampling_rate = dbs_data->sampling_rate;
520 : 2 : ignore_nice = dbs_data->ignore_nice_load;
521 : 2 : io_busy = dbs_data->io_is_busy;
522 : :
523 : 2 : for_each_cpu(j, policy->cpus) {
524 : 2 : struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j);
525 : :
526 : 2 : j_cdbs->prev_cpu_idle = get_cpu_idle_time(j, &j_cdbs->prev_update_time, io_busy);
527 : : /*
528 : : * Make the first invocation of dbs_update() compute the load.
529 : : */
530 : 2 : j_cdbs->prev_load = 0;
531 : :
532 : 2 : if (ignore_nice)
533 : 0 : j_cdbs->prev_cpu_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE];
534 : : }
535 : :
536 : 2 : gov->start(policy);
537 : :
538 : 2 : gov_set_update_util(policy_dbs, sampling_rate);
539 : 2 : return 0;
540 : : }
541 : : EXPORT_SYMBOL_GPL(cpufreq_dbs_governor_start);
542 : :
543 : 0 : void cpufreq_dbs_governor_stop(struct cpufreq_policy *policy)
544 : : {
545 : 0 : struct policy_dbs_info *policy_dbs = policy->governor_data;
546 : :
547 : 0 : gov_clear_update_util(policy_dbs->policy);
548 : 0 : irq_work_sync(&policy_dbs->irq_work);
549 : 0 : cancel_work_sync(&policy_dbs->work);
550 : : atomic_set(&policy_dbs->work_count, 0);
551 : 0 : policy_dbs->work_in_progress = false;
552 : 0 : }
553 : : EXPORT_SYMBOL_GPL(cpufreq_dbs_governor_stop);
554 : :
555 : 2 : void cpufreq_dbs_governor_limits(struct cpufreq_policy *policy)
556 : : {
557 : : struct policy_dbs_info *policy_dbs;
558 : :
559 : : /* Protect gov->gdbs_data against cpufreq_dbs_governor_exit() */
560 : 2 : mutex_lock(&gov_dbs_data_mutex);
561 : 2 : policy_dbs = policy->governor_data;
562 : 2 : if (!policy_dbs)
563 : : goto out;
564 : :
565 : 2 : mutex_lock(&policy_dbs->update_mutex);
566 : 2 : cpufreq_policy_apply_limits(policy);
567 : : gov_update_sample_delay(policy_dbs, 0);
568 : 2 : mutex_unlock(&policy_dbs->update_mutex);
569 : :
570 : : out:
571 : 2 : mutex_unlock(&gov_dbs_data_mutex);
572 : 2 : }
573 : : EXPORT_SYMBOL_GPL(cpufreq_dbs_governor_limits);
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