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