drivers/cpufreq/cpufreq_governor.c

   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 <asm/cputime.h>
  20 #include <linux/cpufreq.h>
  21 #include <linux/cpumask.h>
  22 #include <linux/export.h>
  23 #include <linux/kernel_stat.h>
  24 #include <linux/mutex.h>
  25 #include <linux/slab.h>
  26 #include <linux/tick.h>
  27 #include <linux/types.h>
  28 #include <linux/workqueue.h>
  29
  30 #include "cpufreq_governor.h"
  31
  32 static struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy)
  33 {
  34         if (have_governor_per_policy())
  35                 return &policy->kobj;
  36         else
  37                 return cpufreq_global_kobject;
  38 }
  39
  40 static struct attribute_group *get_sysfs_attr(struct dbs_data *dbs_data)
  41 {
  42         if (have_governor_per_policy())
  43                 return dbs_data->cdata->attr_group_gov_pol;
  44         else
  45                 return dbs_data->cdata->attr_group_gov_sys;
  46 }
  47
  48 static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
  49 {
  50         u64 idle_time;
  51         u64 cur_wall_time;
  52         u64 busy_time;
  53
  54         cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
  55
  56         busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
  57         busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM];
  58         busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
  59         busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
  60         busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
  61         busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
  62
  63         idle_time = cur_wall_time - busy_time;
  64         if (wall)
  65                 *wall = cputime_to_usecs(cur_wall_time);
  66
  67         return cputime_to_usecs(idle_time);
  68 }
  69
  70 u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy)
  71 {
  72         u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL);
  73
  74         if (idle_time == -1ULL)
  75                 return get_cpu_idle_time_jiffy(cpu, wall);
  76         else if (!io_busy)
  77                 idle_time += get_cpu_iowait_time_us(cpu, wall);
  78
  79         return idle_time;
  80 }
  81 EXPORT_SYMBOL_GPL(get_cpu_idle_time);
  82
  83 void dbs_check_cpu(struct dbs_data *dbs_data, int cpu)
  84 {
  85         struct cpu_dbs_common_info *cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
  86         struct od_dbs_tuners *od_tuners = dbs_data->tuners;
  87         struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
  88         struct cpufreq_policy *policy;
  89         unsigned int max_load = 0;
  90         unsigned int ignore_nice;
  91         unsigned int j;
  92
  93         if (dbs_data->cdata->governor == GOV_ONDEMAND)
  94                 ignore_nice = od_tuners->ignore_nice;
  95         else
  96                 ignore_nice = cs_tuners->ignore_nice;
  97
  98         policy = cdbs->cur_policy;
  99
 100         /* Get Absolute Load (in terms of freq for ondemand gov) */
 101         for_each_cpu(j, policy->cpus) {
 102                 struct cpu_dbs_common_info *j_cdbs;
 103                 u64 cur_wall_time, cur_idle_time;
 104                 unsigned int idle_time, wall_time;
 105                 unsigned int load;
 106                 int io_busy = 0;
 107
 108                 j_cdbs = dbs_data->cdata->get_cpu_cdbs(j);
 109
 110                 /*
 111                  * For the purpose of ondemand, waiting for disk IO is
 112                  * an indication that you're performance critical, and
 113                  * not that the system is actually idle. So do not add
 114                  * the iowait time to the cpu idle time.
 115                  */
 116                 if (dbs_data->cdata->governor == GOV_ONDEMAND)
 117                         io_busy = od_tuners->io_is_busy;
 118                 cur_idle_time = get_cpu_idle_time(j, &cur_wall_time, io_busy);
 119
 120                 wall_time = (unsigned int)
 121                         (cur_wall_time - j_cdbs->prev_cpu_wall);
 122                 j_cdbs->prev_cpu_wall = cur_wall_time;
 123
 124                 idle_time = (unsigned int)
 125                         (cur_idle_time - j_cdbs->prev_cpu_idle);
 126                 j_cdbs->prev_cpu_idle = cur_idle_time;
 127
 128                 if (ignore_nice) {
 129                         u64 cur_nice;
 130                         unsigned long cur_nice_jiffies;
 131
 132                         cur_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE] -
 133                                          cdbs->prev_cpu_nice;
 134                         /*
 135                          * Assumption: nice time between sampling periods will
 136                          * be less than 2^32 jiffies for 32 bit sys
 137                          */
 138                         cur_nice_jiffies = (unsigned long)
 139                                         cputime64_to_jiffies64(cur_nice);
 140
 141                         cdbs->prev_cpu_nice =
 142                                 kcpustat_cpu(j).cpustat[CPUTIME_NICE];
 143                         idle_time += jiffies_to_usecs(cur_nice_jiffies);
 144                 }
 145
 146                 if (unlikely(!wall_time || wall_time < idle_time))
 147                         continue;
 148
 149                 load = 100 * (wall_time - idle_time) / wall_time;
 150
 151                 if (dbs_data->cdata->governor == GOV_ONDEMAND) {
 152                         int freq_avg = __cpufreq_driver_getavg(policy, j);
 153                         if (freq_avg <= 0)
 154                                 freq_avg = policy->cur;
 155
 156                         load *= freq_avg;
 157                 }
 158
 159                 if (load > max_load)
 160                         max_load = load;
 161         }
 162
 163         dbs_data->cdata->gov_check_cpu(cpu, max_load);
 164 }
 165 EXPORT_SYMBOL_GPL(dbs_check_cpu);
 166
 167 static inline void __gov_queue_work(int cpu, struct dbs_data *dbs_data,
 168                 unsigned int delay)
 169 {
 170         struct cpu_dbs_common_info *cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
 171
 172         mod_delayed_work_on(cpu, system_wq, &cdbs->work, delay);
 173 }
 174
 175 void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy,
 176                 unsigned int delay, bool all_cpus)
 177 {
 178         int i;
 179
 180         if (!all_cpus) {
 181                 __gov_queue_work(smp_processor_id(), dbs_data, delay);
 182         } else {
 183                 for_each_cpu(i, policy->cpus)
 184                         __gov_queue_work(i, dbs_data, delay);
 185         }
 186 }
 187 EXPORT_SYMBOL_GPL(gov_queue_work);
 188
 189 static inline void gov_cancel_work(struct dbs_data *dbs_data,
 190                 struct cpufreq_policy *policy)
 191 {
 192         struct cpu_dbs_common_info *cdbs;
 193         int i;
 194
 195         for_each_cpu(i, policy->cpus) {
 196                 cdbs = dbs_data->cdata->get_cpu_cdbs(i);
 197                 cancel_delayed_work_sync(&cdbs->work);
 198         }
 199 }
 200
 201 /* Will return if we need to evaluate cpu load again or not */
 202 bool need_load_eval(struct cpu_dbs_common_info *cdbs,
 203                 unsigned int sampling_rate)
 204 {
 205         if (policy_is_shared(cdbs->cur_policy)) {
 206                 ktime_t time_now = ktime_get();
 207                 s64 delta_us = ktime_us_delta(time_now, cdbs->time_stamp);
 208
 209                 /* Do nothing if we recently have sampled */
 210                 if (delta_us < (s64)(sampling_rate / 2))
 211                         return false;
 212                 else
 213                         cdbs->time_stamp = time_now;
 214         }
 215
 216         return true;
 217 }
 218 EXPORT_SYMBOL_GPL(need_load_eval);
 219
 220 static void set_sampling_rate(struct dbs_data *dbs_data,
 221                 unsigned int sampling_rate)
 222 {
 223         if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
 224                 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
 225                 cs_tuners->sampling_rate = sampling_rate;
 226         } else {
 227                 struct od_dbs_tuners *od_tuners = dbs_data->tuners;
 228                 od_tuners->sampling_rate = sampling_rate;
 229         }
 230 }
 231
 232 int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 233                 struct common_dbs_data *cdata, unsigned int event)
 234 {
 235         struct dbs_data *dbs_data;
 236         struct od_cpu_dbs_info_s *od_dbs_info = NULL;
 237         struct cs_cpu_dbs_info_s *cs_dbs_info = NULL;
 238         struct od_ops *od_ops = NULL;
 239         struct od_dbs_tuners *od_tuners = NULL;
 240         struct cs_dbs_tuners *cs_tuners = NULL;
 241         struct cpu_dbs_common_info *cpu_cdbs;
 242         unsigned int sampling_rate, latency, ignore_nice, j, cpu = policy->cpu;
 243         int io_busy = 0;
 244         int rc;
 245
 246         if (have_governor_per_policy())
 247                 dbs_data = policy->governor_data;
 248         else
 249                 dbs_data = cdata->gdbs_data;
 250
 251         WARN_ON(!dbs_data && (event != CPUFREQ_GOV_POLICY_INIT));
 252
 253         switch (event) {
 254         case CPUFREQ_GOV_POLICY_INIT:
 255                 if (have_governor_per_policy()) {
 256                         WARN_ON(dbs_data);
 257                 } else if (dbs_data) {
 258                         policy->governor_data = dbs_data;
 259                         return 0;
 260                 }
 261
 262                 dbs_data = kzalloc(sizeof(*dbs_data), GFP_KERNEL);
 263                 if (!dbs_data) {
 264                         pr_err("%s: POLICY_INIT: kzalloc failed\n", __func__);
 265                         return -ENOMEM;
 266                 }
 267
 268                 dbs_data->cdata = cdata;
 269                 rc = cdata->init(dbs_data);
 270                 if (rc) {
 271                         pr_err("%s: POLICY_INIT: init() failed\n", __func__);
 272                         kfree(dbs_data);
 273                         return rc;
 274                 }
 275
 276                 rc = sysfs_create_group(get_governor_parent_kobj(policy),
 277                                 get_sysfs_attr(dbs_data));
 278                 if (rc) {
 279                         cdata->exit(dbs_data);
 280                         kfree(dbs_data);
 281                         return rc;
 282                 }
 283
 284                 policy->governor_data = dbs_data;
 285
 286                 /* policy latency is in nS. Convert it to uS first */
 287                 latency = policy->cpuinfo.transition_latency / 1000;
 288                 if (latency == 0)
 289                         latency = 1;
 290
 291                 /* Bring kernel and HW constraints together */
 292                 dbs_data->min_sampling_rate = max(dbs_data->min_sampling_rate,
 293                                 MIN_LATENCY_MULTIPLIER * latency);
 294                 set_sampling_rate(dbs_data, max(dbs_data->min_sampling_rate,
 295                                         latency * LATENCY_MULTIPLIER));
 296
 297                 if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
 298                         struct cs_ops *cs_ops = dbs_data->cdata->gov_ops;
 299
 300                         cpufreq_register_notifier(cs_ops->notifier_block,
 301                                         CPUFREQ_TRANSITION_NOTIFIER);
 302                 }
 303
 304                 if (!have_governor_per_policy())
 305                         cdata->gdbs_data = dbs_data;
 306
 307                 return 0;
 308         case CPUFREQ_GOV_POLICY_EXIT:
 309                 if ((policy->governor->initialized == 1) ||
 310                                 have_governor_per_policy()) {
 311                         sysfs_remove_group(get_governor_parent_kobj(policy),
 312                                         get_sysfs_attr(dbs_data));
 313
 314                         if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
 315                                 struct cs_ops *cs_ops = dbs_data->cdata->gov_ops;
 316
 317                                 cpufreq_unregister_notifier(cs_ops->notifier_block,
 318                                                 CPUFREQ_TRANSITION_NOTIFIER);
 319                         }
 320
 321                         cdata->exit(dbs_data);
 322                         kfree(dbs_data);
 323                         cdata->gdbs_data = NULL;
 324                 }
 325
 326                 policy->governor_data = NULL;
 327                 return 0;
 328         }
 329
 330         cpu_cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
 331
 332         if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
 333                 cs_tuners = dbs_data->tuners;
 334                 cs_dbs_info = dbs_data->cdata->get_cpu_dbs_info_s(cpu);
 335                 sampling_rate = cs_tuners->sampling_rate;
 336                 ignore_nice = cs_tuners->ignore_nice;
 337         } else {
 338                 od_tuners = dbs_data->tuners;
 339                 od_dbs_info = dbs_data->cdata->get_cpu_dbs_info_s(cpu);
 340                 sampling_rate = od_tuners->sampling_rate;
 341                 ignore_nice = od_tuners->ignore_nice;
 342                 od_ops = dbs_data->cdata->gov_ops;
 343                 io_busy = od_tuners->io_is_busy;
 344         }
 345
 346         switch (event) {
 347         case CPUFREQ_GOV_START:
 348                 if (!policy->cur)
 349                         return -EINVAL;
 350
 351                 mutex_lock(&dbs_data->mutex);
 352
 353                 for_each_cpu(j, policy->cpus) {
 354                         struct cpu_dbs_common_info *j_cdbs =
 355                                 dbs_data->cdata->get_cpu_cdbs(j);
 356
 357                         j_cdbs->cpu = j;
 358                         j_cdbs->cur_policy = policy;
 359                         j_cdbs->prev_cpu_idle = get_cpu_idle_time(j,
 360                                                &j_cdbs->prev_cpu_wall, io_busy);
 361                         if (ignore_nice)
 362                                 j_cdbs->prev_cpu_nice =
 363                                         kcpustat_cpu(j).cpustat[CPUTIME_NICE];
 364
 365                         mutex_init(&j_cdbs->timer_mutex);
 366                         INIT_DEFERRABLE_WORK(&j_cdbs->work,
 367                                              dbs_data->cdata->gov_dbs_timer);
 368                 }
 369
 370                 /*
 371                  * conservative does not implement micro like ondemand
 372                  * governor, thus we are bound to jiffes/HZ
 373                  */
 374                 if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
 375                         cs_dbs_info->down_skip = 0;
 376                         cs_dbs_info->enable = 1;
 377                         cs_dbs_info->requested_freq = policy->cur;
 378                 } else {
 379                         od_dbs_info->rate_mult = 1;
 380                         od_dbs_info->sample_type = OD_NORMAL_SAMPLE;
 381                         od_ops->powersave_bias_init_cpu(cpu);
 382                 }
 383
 384                 mutex_unlock(&dbs_data->mutex);
 385
 386                 /* Initiate timer time stamp */
 387                 cpu_cdbs->time_stamp = ktime_get();
 388
 389                 gov_queue_work(dbs_data, policy,
 390                                 delay_for_sampling_rate(sampling_rate), true);
 391                 break;
 392
 393         case CPUFREQ_GOV_STOP:
 394                 if (dbs_data->cdata->governor == GOV_CONSERVATIVE)
 395                         cs_dbs_info->enable = 0;
 396
 397                 gov_cancel_work(dbs_data, policy);
 398
 399                 mutex_lock(&dbs_data->mutex);
 400                 mutex_destroy(&cpu_cdbs->timer_mutex);
 401
 402                 mutex_unlock(&dbs_data->mutex);
 403
 404                 break;
 405
 406         case CPUFREQ_GOV_LIMITS:
 407                 mutex_lock(&cpu_cdbs->timer_mutex);
 408                 if (policy->max < cpu_cdbs->cur_policy->cur)
 409                         __cpufreq_driver_target(cpu_cdbs->cur_policy,
 410                                         policy->max, CPUFREQ_RELATION_H);
 411                 else if (policy->min > cpu_cdbs->cur_policy->cur)
 412                         __cpufreq_driver_target(cpu_cdbs->cur_policy,
 413                                         policy->min, CPUFREQ_RELATION_L);
 414                 dbs_check_cpu(dbs_data, cpu);
 415                 mutex_unlock(&cpu_cdbs->timer_mutex);
 416                 break;
 417         }
 418         return 0;
 419 }
 420 EXPORT_SYMBOL_GPL(cpufreq_governor_dbs);