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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
24static DEFINE_PER_CPU(struct cpu_dbs_info, cpu_dbs);
25
26static DEFINE_MUTEX(gov_dbs_data_mutex);
27
28/* Common sysfs tunables */
29/*
30 * sampling_rate_store - 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 */
44ssize_t sampling_rate_store(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 ret = sscanf(buf, "%u", &sampling_interval);
53 if (ret != 1 || sampling_interval < CPUFREQ_DBS_MIN_SAMPLING_INTERVAL)
54 return -EINVAL;
55
56 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 list_for_each_entry(policy_dbs, &attr_set->policy_list, list) {
63 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 mutex_unlock(&policy_dbs->update_mutex);
79 }
80
81 return count;
82}
83EXPORT_SYMBOL_GPL(sampling_rate_store);
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 */
95void gov_update_cpu_data(struct dbs_data *dbs_data)
96{
97 struct policy_dbs_info *policy_dbs;
98
99 list_for_each_entry(policy_dbs, &dbs_data->attr_set.policy_list, list) {
100 unsigned int j;
101
102 for_each_cpu(j, policy_dbs->policy->cpus) {
103 struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j);
104
105 j_cdbs->prev_cpu_idle = get_cpu_idle_time(j, &j_cdbs->prev_update_time,
106 dbs_data->io_is_busy);
107 if (dbs_data->ignore_nice_load)
108 j_cdbs->prev_cpu_nice = kcpustat_field(&kcpustat_cpu(j), CPUTIME_NICE, j);
109 }
110 }
111}
112EXPORT_SYMBOL_GPL(gov_update_cpu_data);
113
114unsigned int dbs_update(struct cpufreq_policy *policy)
115{
116 struct policy_dbs_info *policy_dbs = policy->governor_data;
117 struct dbs_data *dbs_data = policy_dbs->dbs_data;
118 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 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 io_busy = dbs_data->io_is_busy;
135
136 /* Get Absolute Load */
137 for_each_cpu(j, policy->cpus) {
138 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 cur_idle_time = get_cpu_idle_time(j, &update_time, io_busy);
144
145 time_elapsed = update_time - j_cdbs->prev_update_time;
146 j_cdbs->prev_update_time = update_time;
147
148 idle_time = cur_idle_time - j_cdbs->prev_cpu_idle;
149 j_cdbs->prev_cpu_idle = cur_idle_time;
150
151 if (ignore_nice) {
152 u64 cur_nice = kcpustat_field(&kcpustat_cpu(j), CPUTIME_NICE, j);
153
154 idle_time += div_u64(cur_nice - j_cdbs->prev_cpu_nice, NSEC_PER_USEC);
155 j_cdbs->prev_cpu_nice = cur_nice;
156 }
157
158 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 load = j_cdbs->prev_load;
165 } 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 j_cdbs->prev_load = 0;
191 } else {
192 if (time_elapsed >= idle_time) {
193 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 load = (int)idle_time < 0 ? 100 : 0;
211 }
212 j_cdbs->prev_load = load;
213 }
214
215 if (unlikely((int)idle_time > 2 * sampling_rate)) {
216 unsigned int periods = idle_time / sampling_rate;
217
218 if (periods < idle_periods)
219 idle_periods = periods;
220 }
221
222 if (load > max_load)
223 max_load = load;
224 }
225
226 policy_dbs->idle_periods = idle_periods;
227
228 return max_load;
229}
230EXPORT_SYMBOL_GPL(dbs_update);
231
232static 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 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 mutex_lock(&policy_dbs->update_mutex);
247 gov_update_sample_delay(policy_dbs, gov->gov_dbs_update(policy));
248 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 smp_wmb();
258 policy_dbs->work_in_progress = false;
259}
260
261static 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 schedule_work_on(smp_processor_id(), &policy_dbs->work);
267}
268
269static 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 struct policy_dbs_info *policy_dbs = cdbs->policy_dbs;
274 u64 delta_ns, lst;
275
276 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 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 smp_rmb();
293 lst = READ_ONCE(policy_dbs->last_sample_time);
294 delta_ns = time - lst;
295 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 if (policy_dbs->is_shared) {
304 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 if (unlikely(lst != READ_ONCE(policy_dbs->last_sample_time))) {
312 atomic_set(&policy_dbs->work_count, 0);
313 return;
314 }
315 }
316
317 policy_dbs->last_sample_time = time;
318 policy_dbs->work_in_progress = true;
319 irq_work_queue(&policy_dbs->irq_work);
320}
321
322static void gov_set_update_util(struct policy_dbs_info *policy_dbs,
323 unsigned int delay_us)
324{
325 struct cpufreq_policy *policy = policy_dbs->policy;
326 int cpu;
327
328 gov_update_sample_delay(policy_dbs, delay_us);
329 policy_dbs->last_sample_time = 0;
330
331 for_each_cpu(cpu, policy->cpus) {
332 struct cpu_dbs_info *cdbs = &per_cpu(cpu_dbs, cpu);
333
334 cpufreq_add_update_util_hook(cpu, &cdbs->update_util,
335 dbs_update_util_handler);
336 }
337}
338
339static inline void gov_clear_update_util(struct cpufreq_policy *policy)
340{
341 int i;
342
343 for_each_cpu(i, policy->cpus)
344 cpufreq_remove_update_util_hook(i);
345
346 synchronize_rcu();
347}
348
349static 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 policy_dbs = gov->alloc();
357 if (!policy_dbs)
358 return NULL;
359
360 policy_dbs->policy = policy;
361 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 INIT_WORK(&policy_dbs->work, dbs_work_handler);
365
366 /* Set policy_dbs for all CPUs, online+offline */
367 for_each_cpu(j, policy->related_cpus) {
368 struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j);
369
370 j_cdbs->policy_dbs = policy_dbs;
371 }
372 return policy_dbs;
373}
374
375static 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 for_each_cpu(j, policy_dbs->policy->related_cpus) {
383 struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j);
384
385 j_cdbs->policy_dbs = NULL;
386 j_cdbs->update_util.func = NULL;
387 }
388 gov->free(policy_dbs);
389}
390
391static void cpufreq_dbs_data_release(struct kobject *kobj)
392{
393 struct dbs_data *dbs_data = to_dbs_data(to_gov_attr_set(kobj));
394 struct dbs_governor *gov = dbs_data->gov;
395
396 gov->exit(dbs_data);
397 kfree(dbs_data);
398}
399
400int cpufreq_dbs_governor_init(struct cpufreq_policy *policy)
401{
402 struct dbs_governor *gov = dbs_governor_of(policy);
403 struct dbs_data *dbs_data;
404 struct policy_dbs_info *policy_dbs;
405 int ret = 0;
406
407 /* State should be equivalent to EXIT */
408 if (policy->governor_data)
409 return -EBUSY;
410
411 policy_dbs = alloc_policy_dbs_info(policy, gov);
412 if (!policy_dbs)
413 return -ENOMEM;
414
415 /* Protect gov->gdbs_data against concurrent updates. */
416 mutex_lock(&gov_dbs_data_mutex);
417
418 dbs_data = gov->gdbs_data;
419 if (dbs_data) {
420 if (WARN_ON(have_governor_per_policy())) {
421 ret = -EINVAL;
422 goto free_policy_dbs_info;
423 }
424 policy_dbs->dbs_data = dbs_data;
425 policy->governor_data = policy_dbs;
426
427 gov_attr_set_get(&dbs_data->attr_set, &policy_dbs->list);
428 goto out;
429 }
430
431 dbs_data = kzalloc(sizeof(*dbs_data), GFP_KERNEL);
432 if (!dbs_data) {
433 ret = -ENOMEM;
434 goto free_policy_dbs_info;
435 }
436
437 dbs_data->gov = gov;
438 gov_attr_set_init(&dbs_data->attr_set, &policy_dbs->list);
439
440 ret = gov->init(dbs_data);
441 if (ret)
442 goto free_dbs_data;
443
444 /*
445 * The sampling interval should not be less than the transition latency
446 * of the CPU and it also cannot be too small for dbs_update() to work
447 * correctly.
448 */
449 dbs_data->sampling_rate = max_t(unsigned int,
450 CPUFREQ_DBS_MIN_SAMPLING_INTERVAL,
451 cpufreq_policy_transition_delay_us(policy));
452
453 if (!have_governor_per_policy())
454 gov->gdbs_data = dbs_data;
455
456 policy_dbs->dbs_data = dbs_data;
457 policy->governor_data = policy_dbs;
458
459 gov->kobj_type.sysfs_ops = &governor_sysfs_ops;
460 gov->kobj_type.release = cpufreq_dbs_data_release;
461 ret = kobject_init_and_add(&dbs_data->attr_set.kobj, &gov->kobj_type,
462 get_governor_parent_kobj(policy),
463 "%s", gov->gov.name);
464 if (!ret)
465 goto out;
466
467 /* Failure, so roll back. */
468 pr_err("initialization failed (dbs_data kobject init error %d)\n", ret);
469
470 kobject_put(&dbs_data->attr_set.kobj);
471
472 policy->governor_data = NULL;
473
474 if (!have_governor_per_policy())
475 gov->gdbs_data = NULL;
476 gov->exit(dbs_data);
477
478free_dbs_data:
479 kfree(dbs_data);
480
481free_policy_dbs_info:
482 free_policy_dbs_info(policy_dbs, gov);
483
484out:
485 mutex_unlock(&gov_dbs_data_mutex);
486 return ret;
487}
488EXPORT_SYMBOL_GPL(cpufreq_dbs_governor_init);
489
490void cpufreq_dbs_governor_exit(struct cpufreq_policy *policy)
491{
492 struct dbs_governor *gov = dbs_governor_of(policy);
493 struct policy_dbs_info *policy_dbs = policy->governor_data;
494 struct dbs_data *dbs_data = policy_dbs->dbs_data;
495 unsigned int count;
496
497 /* Protect gov->gdbs_data against concurrent updates. */
498 mutex_lock(&gov_dbs_data_mutex);
499
500 count = gov_attr_set_put(&dbs_data->attr_set, &policy_dbs->list);
501
502 policy->governor_data = NULL;
503
504 if (!count && !have_governor_per_policy())
505 gov->gdbs_data = NULL;
506
507 free_policy_dbs_info(policy_dbs, gov);
508
509 mutex_unlock(&gov_dbs_data_mutex);
510}
511EXPORT_SYMBOL_GPL(cpufreq_dbs_governor_exit);
512
513int cpufreq_dbs_governor_start(struct cpufreq_policy *policy)
514{
515 struct dbs_governor *gov = dbs_governor_of(policy);
516 struct policy_dbs_info *policy_dbs = policy->governor_data;
517 struct dbs_data *dbs_data = policy_dbs->dbs_data;
518 unsigned int sampling_rate, ignore_nice, j;
519 unsigned int io_busy;
520
521 if (!policy->cur)
522 return -EINVAL;
523
524 policy_dbs->is_shared = policy_is_shared(policy);
525 policy_dbs->rate_mult = 1;
526
527 sampling_rate = dbs_data->sampling_rate;
528 ignore_nice = dbs_data->ignore_nice_load;
529 io_busy = dbs_data->io_is_busy;
530
531 for_each_cpu(j, policy->cpus) {
532 struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j);
533
534 j_cdbs->prev_cpu_idle = get_cpu_idle_time(j, &j_cdbs->prev_update_time, io_busy);
535 /*
536 * Make the first invocation of dbs_update() compute the load.
537 */
538 j_cdbs->prev_load = 0;
539
540 if (ignore_nice)
541 j_cdbs->prev_cpu_nice = kcpustat_field(&kcpustat_cpu(j), CPUTIME_NICE, j);
542 }
543
544 gov->start(policy);
545
546 gov_set_update_util(policy_dbs, sampling_rate);
547 return 0;
548}
549EXPORT_SYMBOL_GPL(cpufreq_dbs_governor_start);
550
551void cpufreq_dbs_governor_stop(struct cpufreq_policy *policy)
552{
553 struct policy_dbs_info *policy_dbs = policy->governor_data;
554
555 gov_clear_update_util(policy_dbs->policy);
556 irq_work_sync(&policy_dbs->irq_work);
557 cancel_work_sync(&policy_dbs->work);
558 atomic_set(&policy_dbs->work_count, 0);
559 policy_dbs->work_in_progress = false;
560}
561EXPORT_SYMBOL_GPL(cpufreq_dbs_governor_stop);
562
563void cpufreq_dbs_governor_limits(struct cpufreq_policy *policy)
564{
565 struct policy_dbs_info *policy_dbs;
566
567 /* Protect gov->gdbs_data against cpufreq_dbs_governor_exit() */
568 mutex_lock(&gov_dbs_data_mutex);
569 policy_dbs = policy->governor_data;
570 if (!policy_dbs)
571 goto out;
572
573 mutex_lock(&policy_dbs->update_mutex);
574 cpufreq_policy_apply_limits(policy);
575 gov_update_sample_delay(policy_dbs, 0);
576 mutex_unlock(&policy_dbs->update_mutex);
577
578out:
579 mutex_unlock(&gov_dbs_data_mutex);
580}
581EXPORT_SYMBOL_GPL(cpufreq_dbs_governor_limits);
1/*
2 * drivers/cpufreq/cpufreq_governor.c
3 *
4 * CPUFREQ governors common code
5 *
6 * Copyright (C) 2001 Russell King
7 * (C) 2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
8 * (C) 2003 Jun Nakajima <jun.nakajima@intel.com>
9 * (C) 2009 Alexander Clouter <alex@digriz.org.uk>
10 * (c) 2012 Viresh Kumar <viresh.kumar@linaro.org>
11 *
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License version 2 as
14 * published by the Free Software Foundation.
15 */
16
17#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
18
19#include <linux/export.h>
20#include <linux/kernel_stat.h>
21#include <linux/slab.h>
22
23#include "cpufreq_governor.h"
24
25static struct attribute_group *get_sysfs_attr(struct dbs_data *dbs_data)
26{
27 if (have_governor_per_policy())
28 return dbs_data->cdata->attr_group_gov_pol;
29 else
30 return dbs_data->cdata->attr_group_gov_sys;
31}
32
33void dbs_check_cpu(struct dbs_data *dbs_data, int cpu)
34{
35 struct cpu_dbs_common_info *cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
36 struct od_dbs_tuners *od_tuners = dbs_data->tuners;
37 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
38 struct cpufreq_policy *policy;
39 unsigned int max_load = 0;
40 unsigned int ignore_nice;
41 unsigned int j;
42
43 if (dbs_data->cdata->governor == GOV_ONDEMAND)
44 ignore_nice = od_tuners->ignore_nice_load;
45 else
46 ignore_nice = cs_tuners->ignore_nice_load;
47
48 policy = cdbs->cur_policy;
49
50 /* Get Absolute Load */
51 for_each_cpu(j, policy->cpus) {
52 struct cpu_dbs_common_info *j_cdbs;
53 u64 cur_wall_time, cur_idle_time;
54 unsigned int idle_time, wall_time;
55 unsigned int load;
56 int io_busy = 0;
57
58 j_cdbs = dbs_data->cdata->get_cpu_cdbs(j);
59
60 /*
61 * For the purpose of ondemand, waiting for disk IO is
62 * an indication that you're performance critical, and
63 * not that the system is actually idle. So do not add
64 * the iowait time to the cpu idle time.
65 */
66 if (dbs_data->cdata->governor == GOV_ONDEMAND)
67 io_busy = od_tuners->io_is_busy;
68 cur_idle_time = get_cpu_idle_time(j, &cur_wall_time, io_busy);
69
70 wall_time = (unsigned int)
71 (cur_wall_time - j_cdbs->prev_cpu_wall);
72 j_cdbs->prev_cpu_wall = cur_wall_time;
73
74 idle_time = (unsigned int)
75 (cur_idle_time - j_cdbs->prev_cpu_idle);
76 j_cdbs->prev_cpu_idle = cur_idle_time;
77
78 if (ignore_nice) {
79 u64 cur_nice;
80 unsigned long cur_nice_jiffies;
81
82 cur_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE] -
83 cdbs->prev_cpu_nice;
84 /*
85 * Assumption: nice time between sampling periods will
86 * be less than 2^32 jiffies for 32 bit sys
87 */
88 cur_nice_jiffies = (unsigned long)
89 cputime64_to_jiffies64(cur_nice);
90
91 cdbs->prev_cpu_nice =
92 kcpustat_cpu(j).cpustat[CPUTIME_NICE];
93 idle_time += jiffies_to_usecs(cur_nice_jiffies);
94 }
95
96 if (unlikely(!wall_time || wall_time < idle_time))
97 continue;
98
99 load = 100 * (wall_time - idle_time) / wall_time;
100
101 if (load > max_load)
102 max_load = load;
103 }
104
105 dbs_data->cdata->gov_check_cpu(cpu, max_load);
106}
107EXPORT_SYMBOL_GPL(dbs_check_cpu);
108
109static inline void __gov_queue_work(int cpu, struct dbs_data *dbs_data,
110 unsigned int delay)
111{
112 struct cpu_dbs_common_info *cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
113
114 mod_delayed_work_on(cpu, system_wq, &cdbs->work, delay);
115}
116
117void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy,
118 unsigned int delay, bool all_cpus)
119{
120 int i;
121
122 mutex_lock(&cpufreq_governor_lock);
123 if (!policy->governor_enabled)
124 goto out_unlock;
125
126 if (!all_cpus) {
127 /*
128 * Use raw_smp_processor_id() to avoid preemptible warnings.
129 * We know that this is only called with all_cpus == false from
130 * works that have been queued with *_work_on() functions and
131 * those works are canceled during CPU_DOWN_PREPARE so they
132 * can't possibly run on any other CPU.
133 */
134 __gov_queue_work(raw_smp_processor_id(), dbs_data, delay);
135 } else {
136 for_each_cpu(i, policy->cpus)
137 __gov_queue_work(i, dbs_data, delay);
138 }
139
140out_unlock:
141 mutex_unlock(&cpufreq_governor_lock);
142}
143EXPORT_SYMBOL_GPL(gov_queue_work);
144
145static inline void gov_cancel_work(struct dbs_data *dbs_data,
146 struct cpufreq_policy *policy)
147{
148 struct cpu_dbs_common_info *cdbs;
149 int i;
150
151 for_each_cpu(i, policy->cpus) {
152 cdbs = dbs_data->cdata->get_cpu_cdbs(i);
153 cancel_delayed_work_sync(&cdbs->work);
154 }
155}
156
157/* Will return if we need to evaluate cpu load again or not */
158bool need_load_eval(struct cpu_dbs_common_info *cdbs,
159 unsigned int sampling_rate)
160{
161 if (policy_is_shared(cdbs->cur_policy)) {
162 ktime_t time_now = ktime_get();
163 s64 delta_us = ktime_us_delta(time_now, cdbs->time_stamp);
164
165 /* Do nothing if we recently have sampled */
166 if (delta_us < (s64)(sampling_rate / 2))
167 return false;
168 else
169 cdbs->time_stamp = time_now;
170 }
171
172 return true;
173}
174EXPORT_SYMBOL_GPL(need_load_eval);
175
176static void set_sampling_rate(struct dbs_data *dbs_data,
177 unsigned int sampling_rate)
178{
179 if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
180 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
181 cs_tuners->sampling_rate = sampling_rate;
182 } else {
183 struct od_dbs_tuners *od_tuners = dbs_data->tuners;
184 od_tuners->sampling_rate = sampling_rate;
185 }
186}
187
188int cpufreq_governor_dbs(struct cpufreq_policy *policy,
189 struct common_dbs_data *cdata, unsigned int event)
190{
191 struct dbs_data *dbs_data;
192 struct od_cpu_dbs_info_s *od_dbs_info = NULL;
193 struct cs_cpu_dbs_info_s *cs_dbs_info = NULL;
194 struct od_ops *od_ops = NULL;
195 struct od_dbs_tuners *od_tuners = NULL;
196 struct cs_dbs_tuners *cs_tuners = NULL;
197 struct cpu_dbs_common_info *cpu_cdbs;
198 unsigned int sampling_rate, latency, ignore_nice, j, cpu = policy->cpu;
199 int io_busy = 0;
200 int rc;
201
202 if (have_governor_per_policy())
203 dbs_data = policy->governor_data;
204 else
205 dbs_data = cdata->gdbs_data;
206
207 WARN_ON(!dbs_data && (event != CPUFREQ_GOV_POLICY_INIT));
208
209 switch (event) {
210 case CPUFREQ_GOV_POLICY_INIT:
211 if (have_governor_per_policy()) {
212 WARN_ON(dbs_data);
213 } else if (dbs_data) {
214 dbs_data->usage_count++;
215 policy->governor_data = dbs_data;
216 return 0;
217 }
218
219 dbs_data = kzalloc(sizeof(*dbs_data), GFP_KERNEL);
220 if (!dbs_data) {
221 pr_err("%s: POLICY_INIT: kzalloc failed\n", __func__);
222 return -ENOMEM;
223 }
224
225 dbs_data->cdata = cdata;
226 dbs_data->usage_count = 1;
227 rc = cdata->init(dbs_data);
228 if (rc) {
229 pr_err("%s: POLICY_INIT: init() failed\n", __func__);
230 kfree(dbs_data);
231 return rc;
232 }
233
234 if (!have_governor_per_policy())
235 WARN_ON(cpufreq_get_global_kobject());
236
237 rc = sysfs_create_group(get_governor_parent_kobj(policy),
238 get_sysfs_attr(dbs_data));
239 if (rc) {
240 cdata->exit(dbs_data);
241 kfree(dbs_data);
242 return rc;
243 }
244
245 policy->governor_data = dbs_data;
246
247 /* policy latency is in ns. Convert it to us first */
248 latency = policy->cpuinfo.transition_latency / 1000;
249 if (latency == 0)
250 latency = 1;
251
252 /* Bring kernel and HW constraints together */
253 dbs_data->min_sampling_rate = max(dbs_data->min_sampling_rate,
254 MIN_LATENCY_MULTIPLIER * latency);
255 set_sampling_rate(dbs_data, max(dbs_data->min_sampling_rate,
256 latency * LATENCY_MULTIPLIER));
257
258 if ((cdata->governor == GOV_CONSERVATIVE) &&
259 (!policy->governor->initialized)) {
260 struct cs_ops *cs_ops = dbs_data->cdata->gov_ops;
261
262 cpufreq_register_notifier(cs_ops->notifier_block,
263 CPUFREQ_TRANSITION_NOTIFIER);
264 }
265
266 if (!have_governor_per_policy())
267 cdata->gdbs_data = dbs_data;
268
269 return 0;
270 case CPUFREQ_GOV_POLICY_EXIT:
271 if (!--dbs_data->usage_count) {
272 sysfs_remove_group(get_governor_parent_kobj(policy),
273 get_sysfs_attr(dbs_data));
274
275 if (!have_governor_per_policy())
276 cpufreq_put_global_kobject();
277
278 if ((dbs_data->cdata->governor == GOV_CONSERVATIVE) &&
279 (policy->governor->initialized == 1)) {
280 struct cs_ops *cs_ops = dbs_data->cdata->gov_ops;
281
282 cpufreq_unregister_notifier(cs_ops->notifier_block,
283 CPUFREQ_TRANSITION_NOTIFIER);
284 }
285
286 cdata->exit(dbs_data);
287 kfree(dbs_data);
288 cdata->gdbs_data = NULL;
289 }
290
291 policy->governor_data = NULL;
292 return 0;
293 }
294
295 cpu_cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
296
297 if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
298 cs_tuners = dbs_data->tuners;
299 cs_dbs_info = dbs_data->cdata->get_cpu_dbs_info_s(cpu);
300 sampling_rate = cs_tuners->sampling_rate;
301 ignore_nice = cs_tuners->ignore_nice_load;
302 } else {
303 od_tuners = dbs_data->tuners;
304 od_dbs_info = dbs_data->cdata->get_cpu_dbs_info_s(cpu);
305 sampling_rate = od_tuners->sampling_rate;
306 ignore_nice = od_tuners->ignore_nice_load;
307 od_ops = dbs_data->cdata->gov_ops;
308 io_busy = od_tuners->io_is_busy;
309 }
310
311 switch (event) {
312 case CPUFREQ_GOV_START:
313 if (!policy->cur)
314 return -EINVAL;
315
316 mutex_lock(&dbs_data->mutex);
317
318 for_each_cpu(j, policy->cpus) {
319 struct cpu_dbs_common_info *j_cdbs =
320 dbs_data->cdata->get_cpu_cdbs(j);
321
322 j_cdbs->cpu = j;
323 j_cdbs->cur_policy = policy;
324 j_cdbs->prev_cpu_idle = get_cpu_idle_time(j,
325 &j_cdbs->prev_cpu_wall, io_busy);
326 if (ignore_nice)
327 j_cdbs->prev_cpu_nice =
328 kcpustat_cpu(j).cpustat[CPUTIME_NICE];
329
330 mutex_init(&j_cdbs->timer_mutex);
331 INIT_DEFERRABLE_WORK(&j_cdbs->work,
332 dbs_data->cdata->gov_dbs_timer);
333 }
334
335 if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
336 cs_dbs_info->down_skip = 0;
337 cs_dbs_info->enable = 1;
338 cs_dbs_info->requested_freq = policy->cur;
339 } else {
340 od_dbs_info->rate_mult = 1;
341 od_dbs_info->sample_type = OD_NORMAL_SAMPLE;
342 od_ops->powersave_bias_init_cpu(cpu);
343 }
344
345 mutex_unlock(&dbs_data->mutex);
346
347 /* Initiate timer time stamp */
348 cpu_cdbs->time_stamp = ktime_get();
349
350 gov_queue_work(dbs_data, policy,
351 delay_for_sampling_rate(sampling_rate), true);
352 break;
353
354 case CPUFREQ_GOV_STOP:
355 if (dbs_data->cdata->governor == GOV_CONSERVATIVE)
356 cs_dbs_info->enable = 0;
357
358 gov_cancel_work(dbs_data, policy);
359
360 mutex_lock(&dbs_data->mutex);
361 mutex_destroy(&cpu_cdbs->timer_mutex);
362 cpu_cdbs->cur_policy = NULL;
363
364 mutex_unlock(&dbs_data->mutex);
365
366 break;
367
368 case CPUFREQ_GOV_LIMITS:
369 mutex_lock(&dbs_data->mutex);
370 if (!cpu_cdbs->cur_policy) {
371 mutex_unlock(&dbs_data->mutex);
372 break;
373 }
374 mutex_lock(&cpu_cdbs->timer_mutex);
375 if (policy->max < cpu_cdbs->cur_policy->cur)
376 __cpufreq_driver_target(cpu_cdbs->cur_policy,
377 policy->max, CPUFREQ_RELATION_H);
378 else if (policy->min > cpu_cdbs->cur_policy->cur)
379 __cpufreq_driver_target(cpu_cdbs->cur_policy,
380 policy->min, CPUFREQ_RELATION_L);
381 dbs_check_cpu(dbs_data, cpu);
382 mutex_unlock(&cpu_cdbs->timer_mutex);
383 mutex_unlock(&dbs_data->mutex);
384 break;
385 }
386 return 0;
387}
388EXPORT_SYMBOL_GPL(cpufreq_governor_dbs);