drivers/cpufreq/cpufreq_ondemand.c

   1 /*
   2  *  drivers/cpufreq/cpufreq_ondemand.c
   3  *
   4  *  Copyright (C)  2001 Russell King
   5  *            (C)  2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
   6  *                      Jun Nakajima <jun.nakajima@intel.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14
  15 #include <linux/cpufreq.h>
  16 #include <linux/init.h>
  17 #include <linux/kernel.h>
  18 #include <linux/kernel_stat.h>
  19 #include <linux/kobject.h>
  20 #include <linux/module.h>
  21 #include <linux/mutex.h>
  22 #include <linux/percpu-defs.h>
  23 #include <linux/slab.h>
  24 #include <linux/sysfs.h>
  25 #include <linux/tick.h>
  26 #include <linux/types.h>
  27 #include <linux/cpu.h>
  28
  29 #include "cpufreq_governor.h"
  30
  31 /* On-demand governor macros */
  32 #define DEF_FREQUENCY_DOWN_DIFFERENTIAL         (10)
  33 #define DEF_FREQUENCY_UP_THRESHOLD              (80)
  34 #define DEF_SAMPLING_DOWN_FACTOR                (1)
  35 #define MAX_SAMPLING_DOWN_FACTOR                (100000)
  36 #define MICRO_FREQUENCY_DOWN_DIFFERENTIAL       (3)
  37 #define MICRO_FREQUENCY_UP_THRESHOLD            (95)
  38 #define MICRO_FREQUENCY_MIN_SAMPLE_RATE         (10000)
  39 #define MIN_FREQUENCY_UP_THRESHOLD              (11)
  40 #define MAX_FREQUENCY_UP_THRESHOLD              (100)
  41
  42 static DEFINE_PER_CPU(struct od_cpu_dbs_info_s, od_cpu_dbs_info);
  43
  44 static struct od_ops od_ops;
  45
  46 #ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND
  47 static struct cpufreq_governor cpufreq_gov_ondemand;
  48 #endif
  49
  50 static void ondemand_powersave_bias_init_cpu(int cpu)
  51 {
  52         struct od_cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info, cpu);
  53
  54         dbs_info->freq_table = cpufreq_frequency_get_table(cpu);
  55         dbs_info->freq_lo = 0;
  56 }
  57
  58 /*
  59  * Not all CPUs want IO time to be accounted as busy; this depends on how
  60  * efficient idling at a higher frequency/voltage is.
  61  * Pavel Machek says this is not so for various generations of AMD and old
  62  * Intel systems.
  63  * Mike Chan (android.com) claims this is also not true for ARM.
  64  * Because of this, whitelist specific known (series) of CPUs by default, and
  65  * leave all others up to the user.
  66  */
  67 static int should_io_be_busy(void)
  68 {
  69 #if defined(CONFIG_X86)
  70         /*
  71          * For Intel, Core 2 (model 15) and later have an efficient idle.
  72          */
  73         if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
  74                         boot_cpu_data.x86 == 6 &&
  75                         boot_cpu_data.x86_model >= 15)
  76                 return 1;
  77 #endif
  78         return 0;
  79 }
  80
  81 /*
  82  * Find right freq to be set now with powersave_bias on.
  83  * Returns the freq_hi to be used right now and will set freq_hi_jiffies,
  84  * freq_lo, and freq_lo_jiffies in percpu area for averaging freqs.
  85  */
  86 static unsigned int generic_powersave_bias_target(struct cpufreq_policy *policy,
  87                 unsigned int freq_next, unsigned int relation)
  88 {
  89         unsigned int freq_req, freq_reduc, freq_avg;
  90         unsigned int freq_hi, freq_lo;
  91         unsigned int index = 0;
  92         unsigned int jiffies_total, jiffies_hi, jiffies_lo;
  93         struct od_cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info,
  94                                                    policy->cpu);
  95         struct dbs_data *dbs_data = policy->governor_data;
  96         struct od_dbs_tuners *od_tuners = dbs_data->tuners;
  97
  98         if (!dbs_info->freq_table) {
  99                 dbs_info->freq_lo = 0;
 100                 dbs_info->freq_lo_jiffies = 0;
 101                 return freq_next;
 102         }
 103
 104         cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_next,
 105                         relation, &index);
 106         freq_req = dbs_info->freq_table[index].frequency;
 107         freq_reduc = freq_req * od_tuners->powersave_bias / 1000;
 108         freq_avg = freq_req - freq_reduc;
 109
 110         /* Find freq bounds for freq_avg in freq_table */
 111         index = 0;
 112         cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_avg,
 113                         CPUFREQ_RELATION_H, &index);
 114         freq_lo = dbs_info->freq_table[index].frequency;
 115         index = 0;
 116         cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_avg,
 117                         CPUFREQ_RELATION_L, &index);
 118         freq_hi = dbs_info->freq_table[index].frequency;
 119
 120         /* Find out how long we have to be in hi and lo freqs */
 121         if (freq_hi == freq_lo) {
 122                 dbs_info->freq_lo = 0;
 123                 dbs_info->freq_lo_jiffies = 0;
 124                 return freq_lo;
 125         }
 126         jiffies_total = usecs_to_jiffies(od_tuners->sampling_rate);
 127         jiffies_hi = (freq_avg - freq_lo) * jiffies_total;
 128         jiffies_hi += ((freq_hi - freq_lo) / 2);
 129         jiffies_hi /= (freq_hi - freq_lo);
 130         jiffies_lo = jiffies_total - jiffies_hi;
 131         dbs_info->freq_lo = freq_lo;
 132         dbs_info->freq_lo_jiffies = jiffies_lo;
 133         dbs_info->freq_hi_jiffies = jiffies_hi;
 134         return freq_hi;
 135 }
 136
 137 static void ondemand_powersave_bias_init(void)
 138 {
 139         int i;
 140         for_each_online_cpu(i) {
 141                 ondemand_powersave_bias_init_cpu(i);
 142         }
 143 }
 144
 145 static void dbs_freq_increase(struct cpufreq_policy *p, unsigned int freq)
 146 {
 147         struct dbs_data *dbs_data = p->governor_data;
 148         struct od_dbs_tuners *od_tuners = dbs_data->tuners;
 149
 150         if (od_tuners->powersave_bias)
 151                 freq = od_ops.powersave_bias_target(p, freq,
 152                                 CPUFREQ_RELATION_H);
 153         else if (p->cur == p->max)
 154                 return;
 155
 156         __cpufreq_driver_target(p, freq, od_tuners->powersave_bias ?
 157                         CPUFREQ_RELATION_L : CPUFREQ_RELATION_H);
 158 }
 159
 160 /*
 161  * Every sampling_rate, we check, if current idle time is less than 20%
 162  * (default), then we try to increase frequency. Every sampling_rate, we look
 163  * for the lowest frequency which can sustain the load while keeping idle time
 164  * over 30%. If such a frequency exist, we try to decrease to this frequency.
 165  *
 166  * Any frequency increase takes it to the maximum frequency. Frequency reduction
 167  * happens at minimum steps of 5% (default) of current frequency
 168  */
 169 static void od_check_cpu(int cpu, unsigned int load_freq)
 170 {
 171         struct od_cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info, cpu);
 172         struct cpufreq_policy *policy = dbs_info->cdbs.cur_policy;
 173         struct dbs_data *dbs_data = policy->governor_data;
 174         struct od_dbs_tuners *od_tuners = dbs_data->tuners;
 175
 176         dbs_info->freq_lo = 0;
 177
 178         /* Check for frequency increase */
 179         if (load_freq > od_tuners->up_threshold * policy->cur) {
 180                 /* If switching to max speed, apply sampling_down_factor */
 181                 if (policy->cur < policy->max)
 182                         dbs_info->rate_mult =
 183                                 od_tuners->sampling_down_factor;
 184                 dbs_freq_increase(policy, policy->max);
 185                 return;
 186         }
 187
 188         /* Check for frequency decrease */
 189         /* if we cannot reduce the frequency anymore, break out early */
 190         if (policy->cur == policy->min)
 191                 return;
 192
 193         /*
 194          * The optimal frequency is the frequency that is the lowest that can
 195          * support the current CPU usage without triggering the up policy. To be
 196          * safe, we focus 10 points under the threshold.
 197          */
 198         if (load_freq < od_tuners->adj_up_threshold
 199                         * policy->cur) {
 200                 unsigned int freq_next;
 201                 freq_next = load_freq / od_tuners->adj_up_threshold;
 202
 203                 /* No longer fully busy, reset rate_mult */
 204                 dbs_info->rate_mult = 1;
 205
 206                 if (freq_next < policy->min)
 207                         freq_next = policy->min;
 208
 209                 if (!od_tuners->powersave_bias) {
 210                         __cpufreq_driver_target(policy, freq_next,
 211                                         CPUFREQ_RELATION_L);
 212                         return;
 213                 }
 214
 215                 freq_next = od_ops.powersave_bias_target(policy, freq_next,
 216                                         CPUFREQ_RELATION_L);
 217                 __cpufreq_driver_target(policy, freq_next, CPUFREQ_RELATION_L);
 218         }
 219 }
 220
 221 static void od_dbs_timer(struct work_struct *work)
 222 {
 223         struct od_cpu_dbs_info_s *dbs_info =
 224                 container_of(work, struct od_cpu_dbs_info_s, cdbs.work.work);
 225         unsigned int cpu = dbs_info->cdbs.cur_policy->cpu;
 226         struct od_cpu_dbs_info_s *core_dbs_info = &per_cpu(od_cpu_dbs_info,
 227                         cpu);
 228         struct dbs_data *dbs_data = dbs_info->cdbs.cur_policy->governor_data;
 229         struct od_dbs_tuners *od_tuners = dbs_data->tuners;
 230         int delay = 0, sample_type = core_dbs_info->sample_type;
 231         bool modify_all = true;
 232
 233         mutex_lock(&core_dbs_info->cdbs.timer_mutex);
 234         if (!need_load_eval(&core_dbs_info->cdbs, od_tuners->sampling_rate)) {
 235                 modify_all = false;
 236                 goto max_delay;
 237         }
 238
 239         /* Common NORMAL_SAMPLE setup */
 240         core_dbs_info->sample_type = OD_NORMAL_SAMPLE;
 241         if (sample_type == OD_SUB_SAMPLE) {
 242                 delay = core_dbs_info->freq_lo_jiffies;
 243                 __cpufreq_driver_target(core_dbs_info->cdbs.cur_policy,
 244                                 core_dbs_info->freq_lo, CPUFREQ_RELATION_H);
 245         } else {
 246                 dbs_check_cpu(dbs_data, cpu);
 247                 if (core_dbs_info->freq_lo) {
 248                         /* Setup timer for SUB_SAMPLE */
 249                         core_dbs_info->sample_type = OD_SUB_SAMPLE;
 250                         delay = core_dbs_info->freq_hi_jiffies;
 251                 }
 252         }
 253
 254 max_delay:
 255         if (!delay)
 256                 delay = delay_for_sampling_rate(od_tuners->sampling_rate
 257                                 * core_dbs_info->rate_mult);
 258
 259         gov_queue_work(dbs_data, dbs_info->cdbs.cur_policy, delay, modify_all);
 260         mutex_unlock(&core_dbs_info->cdbs.timer_mutex);
 261 }
 262
 263 /************************** sysfs interface ************************/
 264 static struct common_dbs_data od_dbs_cdata;
 265
 266 /**
 267  * update_sampling_rate - update sampling rate effective immediately if needed.
 268  * @new_rate: new sampling rate
 269  *
 270  * If new rate is smaller than the old, simply updating
 271  * dbs_tuners_int.sampling_rate might not be appropriate. For example, if the
 272  * original sampling_rate was 1 second and the requested new sampling rate is 10
 273  * ms because the user needs immediate reaction from ondemand governor, but not
 274  * sure if higher frequency will be required or not, then, the governor may
 275  * change the sampling rate too late; up to 1 second later. Thus, if we are
 276  * reducing the sampling rate, we need to make the new value effective
 277  * immediately.
 278  */
 279 static void update_sampling_rate(struct dbs_data *dbs_data,
 280                 unsigned int new_rate)
 281 {
 282         struct od_dbs_tuners *od_tuners = dbs_data->tuners;
 283         int cpu;
 284
 285         od_tuners->sampling_rate = new_rate = max(new_rate,
 286                         dbs_data->min_sampling_rate);
 287
 288         for_each_online_cpu(cpu) {
 289                 struct cpufreq_policy *policy;
 290                 struct od_cpu_dbs_info_s *dbs_info;
 291                 unsigned long next_sampling, appointed_at;
 292
 293                 policy = cpufreq_cpu_get(cpu);
 294                 if (!policy)
 295                         continue;
 296                 if (policy->governor != &cpufreq_gov_ondemand) {
 297                         cpufreq_cpu_put(policy);
 298                         continue;
 299                 }
 300                 dbs_info = &per_cpu(od_cpu_dbs_info, cpu);
 301                 cpufreq_cpu_put(policy);
 302
 303                 mutex_lock(&dbs_info->cdbs.timer_mutex);
 304
 305                 if (!delayed_work_pending(&dbs_info->cdbs.work)) {
 306                         mutex_unlock(&dbs_info->cdbs.timer_mutex);
 307                         continue;
 308                 }
 309
 310                 next_sampling = jiffies + usecs_to_jiffies(new_rate);
 311                 appointed_at = dbs_info->cdbs.work.timer.expires;
 312
 313                 if (time_before(next_sampling, appointed_at)) {
 314
 315                         mutex_unlock(&dbs_info->cdbs.timer_mutex);
 316                         cancel_delayed_work_sync(&dbs_info->cdbs.work);
 317                         mutex_lock(&dbs_info->cdbs.timer_mutex);
 318
 319                         gov_queue_work(dbs_data, dbs_info->cdbs.cur_policy,
 320                                         usecs_to_jiffies(new_rate), true);
 321
 322                 }
 323                 mutex_unlock(&dbs_info->cdbs.timer_mutex);
 324         }
 325 }
 326
 327 static ssize_t store_sampling_rate(struct dbs_data *dbs_data, const char *buf,
 328                 size_t count)
 329 {
 330         unsigned int input;
 331         int ret;
 332         ret = sscanf(buf, "%u", &input);
 333         if (ret != 1)
 334                 return -EINVAL;
 335
 336         update_sampling_rate(dbs_data, input);
 337         return count;
 338 }
 339
 340 static ssize_t store_io_is_busy(struct dbs_data *dbs_data, const char *buf,
 341                 size_t count)
 342 {
 343         struct od_dbs_tuners *od_tuners = dbs_data->tuners;
 344         unsigned int input;
 345         int ret;
 346         unsigned int j;
 347
 348         ret = sscanf(buf, "%u", &input);
 349         if (ret != 1)
 350                 return -EINVAL;
 351         od_tuners->io_is_busy = !!input;
 352
 353         /* we need to re-evaluate prev_cpu_idle */
 354         for_each_online_cpu(j) {
 355                 struct od_cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info,
 356                                                                         j);
 357                 dbs_info->cdbs.prev_cpu_idle = get_cpu_idle_time(j,
 358                         &dbs_info->cdbs.prev_cpu_wall, od_tuners->io_is_busy);
 359         }
 360         return count;
 361 }
 362
 363 static ssize_t store_up_threshold(struct dbs_data *dbs_data, const char *buf,
 364                 size_t count)
 365 {
 366         struct od_dbs_tuners *od_tuners = dbs_data->tuners;
 367         unsigned int input;
 368         int ret;
 369         ret = sscanf(buf, "%u", &input);
 370
 371         if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD ||
 372                         input < MIN_FREQUENCY_UP_THRESHOLD) {
 373                 return -EINVAL;
 374         }
 375         /* Calculate the new adj_up_threshold */
 376         od_tuners->adj_up_threshold += input;
 377         od_tuners->adj_up_threshold -= od_tuners->up_threshold;
 378
 379         od_tuners->up_threshold = input;
 380         return count;
 381 }
 382
 383 static ssize_t store_sampling_down_factor(struct dbs_data *dbs_data,
 384                 const char *buf, size_t count)
 385 {
 386         struct od_dbs_tuners *od_tuners = dbs_data->tuners;
 387         unsigned int input, j;
 388         int ret;
 389         ret = sscanf(buf, "%u", &input);
 390
 391         if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1)
 392                 return -EINVAL;
 393         od_tuners->sampling_down_factor = input;
 394
 395         /* Reset down sampling multiplier in case it was active */
 396         for_each_online_cpu(j) {
 397                 struct od_cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info,
 398                                 j);
 399                 dbs_info->rate_mult = 1;
 400         }
 401         return count;
 402 }
 403
 404 static ssize_t store_ignore_nice(struct dbs_data *dbs_data, const char *buf,
 405                 size_t count)
 406 {
 407         struct od_dbs_tuners *od_tuners = dbs_data->tuners;
 408         unsigned int input;
 409         int ret;
 410
 411         unsigned int j;
 412
 413         ret = sscanf(buf, "%u", &input);
 414         if (ret != 1)
 415                 return -EINVAL;
 416
 417         if (input > 1)
 418                 input = 1;
 419
 420         if (input == od_tuners->ignore_nice) { /* nothing to do */
 421                 return count;
 422         }
 423         od_tuners->ignore_nice = input;
 424
 425         /* we need to re-evaluate prev_cpu_idle */
 426         for_each_online_cpu(j) {
 427                 struct od_cpu_dbs_info_s *dbs_info;
 428                 dbs_info = &per_cpu(od_cpu_dbs_info, j);
 429                 dbs_info->cdbs.prev_cpu_idle = get_cpu_idle_time(j,
 430                         &dbs_info->cdbs.prev_cpu_wall, od_tuners->io_is_busy);
 431                 if (od_tuners->ignore_nice)
 432                         dbs_info->cdbs.prev_cpu_nice =
 433                                 kcpustat_cpu(j).cpustat[CPUTIME_NICE];
 434
 435         }
 436         return count;
 437 }
 438
 439 static ssize_t store_powersave_bias(struct dbs_data *dbs_data, const char *buf,
 440                 size_t count)
 441 {
 442         struct od_dbs_tuners *od_tuners = dbs_data->tuners;
 443         unsigned int input;
 444         int ret;
 445         ret = sscanf(buf, "%u", &input);
 446
 447         if (ret != 1)
 448                 return -EINVAL;
 449
 450         if (input > 1000)
 451                 input = 1000;
 452
 453         od_tuners->powersave_bias = input;
 454         ondemand_powersave_bias_init();
 455         return count;
 456 }
 457
 458 show_store_one(od, sampling_rate);
 459 show_store_one(od, io_is_busy);
 460 show_store_one(od, up_threshold);
 461 show_store_one(od, sampling_down_factor);
 462 show_store_one(od, ignore_nice);
 463 show_store_one(od, powersave_bias);
 464 declare_show_sampling_rate_min(od);
 465
 466 gov_sys_pol_attr_rw(sampling_rate);
 467 gov_sys_pol_attr_rw(io_is_busy);
 468 gov_sys_pol_attr_rw(up_threshold);
 469 gov_sys_pol_attr_rw(sampling_down_factor);
 470 gov_sys_pol_attr_rw(ignore_nice);
 471 gov_sys_pol_attr_rw(powersave_bias);
 472 gov_sys_pol_attr_ro(sampling_rate_min);
 473
 474 static struct attribute *dbs_attributes_gov_sys[] = {
 475         &sampling_rate_min_gov_sys.attr,
 476         &sampling_rate_gov_sys.attr,
 477         &up_threshold_gov_sys.attr,
 478         &sampling_down_factor_gov_sys.attr,
 479         &ignore_nice_gov_sys.attr,
 480         &powersave_bias_gov_sys.attr,
 481         &io_is_busy_gov_sys.attr,
 482         NULL
 483 };
 484
 485 static struct attribute_group od_attr_group_gov_sys = {
 486         .attrs = dbs_attributes_gov_sys,
 487         .name = "ondemand",
 488 };
 489
 490 static struct attribute *dbs_attributes_gov_pol[] = {
 491         &sampling_rate_min_gov_pol.attr,
 492         &sampling_rate_gov_pol.attr,
 493         &up_threshold_gov_pol.attr,
 494         &sampling_down_factor_gov_pol.attr,
 495         &ignore_nice_gov_pol.attr,
 496         &powersave_bias_gov_pol.attr,
 497         &io_is_busy_gov_pol.attr,
 498         NULL
 499 };
 500
 501 static struct attribute_group od_attr_group_gov_pol = {
 502         .attrs = dbs_attributes_gov_pol,
 503         .name = "ondemand",
 504 };
 505
 506 /************************** sysfs end ************************/
 507
 508 static int od_init(struct dbs_data *dbs_data)
 509 {
 510         struct od_dbs_tuners *tuners;
 511         u64 idle_time;
 512         int cpu;
 513
 514         tuners = kzalloc(sizeof(struct od_dbs_tuners), GFP_KERNEL);
 515         if (!tuners) {
 516                 pr_err("%s: kzalloc failed\n", __func__);
 517                 return -ENOMEM;
 518         }
 519
 520         cpu = get_cpu();
 521         idle_time = get_cpu_idle_time_us(cpu, NULL);
 522         put_cpu();
 523         if (idle_time != -1ULL) {
 524                 /* Idle micro accounting is supported. Use finer thresholds */
 525                 tuners->up_threshold = MICRO_FREQUENCY_UP_THRESHOLD;
 526                 tuners->adj_up_threshold = MICRO_FREQUENCY_UP_THRESHOLD -
 527                         MICRO_FREQUENCY_DOWN_DIFFERENTIAL;
 528                 /*
 529                  * In nohz/micro accounting case we set the minimum frequency
 530                  * not depending on HZ, but fixed (very low). The deferred
 531                  * timer might skip some samples if idle/sleeping as needed.
 532                 */
 533                 dbs_data->min_sampling_rate = MICRO_FREQUENCY_MIN_SAMPLE_RATE;
 534         } else {
 535                 tuners->up_threshold = DEF_FREQUENCY_UP_THRESHOLD;
 536                 tuners->adj_up_threshold = DEF_FREQUENCY_UP_THRESHOLD -
 537                         DEF_FREQUENCY_DOWN_DIFFERENTIAL;
 538
 539                 /* For correct statistics, we need 10 ticks for each measure */
 540                 dbs_data->min_sampling_rate = MIN_SAMPLING_RATE_RATIO *
 541                         jiffies_to_usecs(10);
 542         }
 543
 544         tuners->sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR;
 545         tuners->ignore_nice = 0;
 546         tuners->powersave_bias = 0;
 547         tuners->io_is_busy = should_io_be_busy();
 548
 549         dbs_data->tuners = tuners;
 550         pr_info("%s: tuners %p\n", __func__, tuners);
 551         mutex_init(&dbs_data->mutex);
 552         return 0;
 553 }
 554
 555 static void od_exit(struct dbs_data *dbs_data)
 556 {
 557         kfree(dbs_data->tuners);
 558 }
 559
 560 define_get_cpu_dbs_routines(od_cpu_dbs_info);
 561
 562 static struct od_ops od_ops = {
 563         .powersave_bias_init_cpu = ondemand_powersave_bias_init_cpu,
 564         .powersave_bias_target = generic_powersave_bias_target,
 565         .freq_increase = dbs_freq_increase,
 566 };
 567
 568 static struct common_dbs_data od_dbs_cdata = {
 569         .governor = GOV_ONDEMAND,
 570         .attr_group_gov_sys = &od_attr_group_gov_sys,
 571         .attr_group_gov_pol = &od_attr_group_gov_pol,
 572         .get_cpu_cdbs = get_cpu_cdbs,
 573         .get_cpu_dbs_info_s = get_cpu_dbs_info_s,
 574         .gov_dbs_timer = od_dbs_timer,
 575         .gov_check_cpu = od_check_cpu,
 576         .gov_ops = &od_ops,
 577         .init = od_init,
 578         .exit = od_exit,
 579 };
 580
 581 static void od_set_powersave_bias(unsigned int powersave_bias)
 582 {
 583         struct cpufreq_policy *policy;
 584         struct dbs_data *dbs_data;
 585         struct od_dbs_tuners *od_tuners;
 586         unsigned int cpu;
 587         cpumask_t done;
 588
 589         cpumask_clear(&done);
 590
 591         get_online_cpus();
 592         for_each_online_cpu(cpu) {
 593                 if (cpumask_test_cpu(cpu, &done))
 594                         continue;
 595
 596                 policy = per_cpu(od_cpu_dbs_info, cpu).cdbs.cur_policy;
 597                 dbs_data = policy->governor_data;
 598                 od_tuners = dbs_data->tuners;
 599                 od_tuners->powersave_bias = powersave_bias;
 600
 601                 cpumask_or(&done, &done, policy->cpus);
 602         }
 603         put_online_cpus();
 604 }
 605
 606 void od_register_powersave_bias_handler(unsigned int (*f)
 607                 (struct cpufreq_policy *, unsigned int, unsigned int),
 608                 unsigned int powersave_bias)
 609 {
 610         od_ops.powersave_bias_target = f;
 611         od_set_powersave_bias(powersave_bias);
 612 }
 613 EXPORT_SYMBOL_GPL(od_register_powersave_bias_handler);
 614
 615 void od_unregister_powersave_bias_handler(void)
 616 {
 617         od_ops.powersave_bias_target = generic_powersave_bias_target;
 618         od_set_powersave_bias(0);
 619 }
 620 EXPORT_SYMBOL_GPL(od_unregister_powersave_bias_handler);
 621
 622 static int od_cpufreq_governor_dbs(struct cpufreq_policy *policy,
 623                 unsigned int event)
 624 {
 625         return cpufreq_governor_dbs(policy, &od_dbs_cdata, event);
 626 }
 627
 628 #ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND
 629 static
 630 #endif
 631 struct cpufreq_governor cpufreq_gov_ondemand = {
 632         .name                   = "ondemand",
 633         .governor               = od_cpufreq_governor_dbs,
 634         .max_transition_latency = TRANSITION_LATENCY_LIMIT,
 635         .owner                  = THIS_MODULE,
 636 };
 637
 638 static int __init cpufreq_gov_dbs_init(void)
 639 {
 640         return cpufreq_register_governor(&cpufreq_gov_ondemand);
 641 }
 642
 643 static void __exit cpufreq_gov_dbs_exit(void)
 644 {
 645         cpufreq_unregister_governor(&cpufreq_gov_ondemand);
 646 }
 647
 648 MODULE_AUTHOR("Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>");
 649 MODULE_AUTHOR("Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>");
 650 MODULE_DESCRIPTION("'cpufreq_ondemand' - A dynamic cpufreq governor for "
 651         "Low Latency Frequency Transition capable processors");
 652 MODULE_LICENSE("GPL");
 653
 654 #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND
 655 fs_initcall(cpufreq_gov_dbs_init);
 656 #else
 657 module_init(cpufreq_gov_dbs_init);
 658 #endif
 659 module_exit(cpufreq_gov_dbs_exit);