drivers/cpufreq/cpufreq_conservative.c

   1 /*
   2  *  drivers/cpufreq/cpufreq_conservative.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  *            (C)  2004 Alexander Clouter <alex-kernel@digriz.org.uk>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/smp.h>
  17 #include <linux/init.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/ctype.h>
  20 #include <linux/cpufreq.h>
  21 #include <linux/sysctl.h>
  22 #include <linux/types.h>
  23 #include <linux/fs.h>
  24 #include <linux/sysfs.h>
  25 #include <linux/cpu.h>
  26 #include <linux/kmod.h>
  27 #include <linux/workqueue.h>
  28 #include <linux/jiffies.h>
  29 #include <linux/kernel_stat.h>
  30 #include <linux/percpu.h>
  31 #include <linux/mutex.h>
  32 /*
  33  * dbs is used in this file as a shortform for demandbased switching
  34  * It helps to keep variable names smaller, simpler
  35  */
  36
  37 #define DEF_FREQUENCY_UP_THRESHOLD              (80)
  38 #define DEF_FREQUENCY_DOWN_THRESHOLD            (20)
  39
  40 /*
  41  * The polling frequency of this governor depends on the capability of
  42  * the processor. Default polling frequency is 1000 times the transition
  43  * latency of the processor. The governor will work on any processor with
  44  * transition latency <= 10mS, using appropriate sampling
  45  * rate.
  46  * For CPUs with transition latency > 10mS (mostly drivers
  47  * with CPUFREQ_ETERNAL), this governor will not work.
  48  * All times here are in uS.
  49  */
  50 static unsigned int def_sampling_rate;
  51 #define MIN_SAMPLING_RATE_RATIO                 (2)
  52 /* for correct statistics, we need at least 10 ticks between each measure */
  53 #define MIN_STAT_SAMPLING_RATE                  \
  54                         (MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10))
  55 #define MIN_SAMPLING_RATE                       \
  56                         (def_sampling_rate / MIN_SAMPLING_RATE_RATIO)
  57 #define MAX_SAMPLING_RATE                       (500 * def_sampling_rate)
  58 #define DEF_SAMPLING_RATE_LATENCY_MULTIPLIER    (1000)
  59 #define DEF_SAMPLING_DOWN_FACTOR                (1)
  60 #define MAX_SAMPLING_DOWN_FACTOR                (10)
  61 #define TRANSITION_LATENCY_LIMIT                (10 * 1000 * 1000)
  62
  63 static void do_dbs_timer(struct work_struct *work);
  64
  65 struct cpu_dbs_info_s {
  66         struct cpufreq_policy *cur_policy;
  67         unsigned int prev_cpu_idle_up;
  68         unsigned int prev_cpu_idle_down;
  69         unsigned int enable;
  70         unsigned int down_skip;
  71         unsigned int requested_freq;
  72 };
  73 static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info);
  74
  75 static unsigned int dbs_enable; /* number of CPUs using this policy */
  76
  77 /*
  78  * DEADLOCK ALERT! There is a ordering requirement between cpu_hotplug
  79  * lock and dbs_mutex. cpu_hotplug lock should always be held before
  80  * dbs_mutex. If any function that can potentially take cpu_hotplug lock
  81  * (like __cpufreq_driver_target()) is being called with dbs_mutex taken, then
  82  * cpu_hotplug lock should be taken before that. Note that cpu_hotplug lock
  83  * is recursive for the same process. -Venki
  84  */
  85 static DEFINE_MUTEX(dbs_mutex);
  86 static DECLARE_DELAYED_WORK(dbs_work, do_dbs_timer);
  87
  88 struct dbs_tuners {
  89         unsigned int sampling_rate;
  90         unsigned int sampling_down_factor;
  91         unsigned int up_threshold;
  92         unsigned int down_threshold;
  93         unsigned int ignore_nice;
  94         unsigned int freq_step;
  95 };
  96
  97 static struct dbs_tuners dbs_tuners_ins = {
  98         .up_threshold = DEF_FREQUENCY_UP_THRESHOLD,
  99         .down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD,
 100         .sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR,
 101         .ignore_nice = 0,
 102         .freq_step = 5,
 103 };
 104
 105 static inline unsigned int get_cpu_idle_time(unsigned int cpu)
 106 {
 107         unsigned int add_nice = 0, ret;
 108
 109         if (dbs_tuners_ins.ignore_nice)
 110                 add_nice = kstat_cpu(cpu).cpustat.nice;
 111
 112         ret = kstat_cpu(cpu).cpustat.idle +
 113                 kstat_cpu(cpu).cpustat.iowait +
 114                 add_nice;
 115
 116         return ret;
 117 }
 118
 119 /* keep track of frequency transitions */
 120 static int
 121 dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
 122                      void *data)
 123 {
 124         struct cpufreq_freqs *freq = data;
 125         struct cpu_dbs_info_s *this_dbs_info = &per_cpu(cpu_dbs_info,
 126                                                         freq->cpu);
 127
 128         if (!this_dbs_info->enable)
 129                 return 0;
 130
 131         this_dbs_info->requested_freq = freq->new;
 132
 133         return 0;
 134 }
 135
 136 static struct notifier_block dbs_cpufreq_notifier_block = {
 137         .notifier_call = dbs_cpufreq_notifier
 138 };
 139
 140 /************************** sysfs interface ************************/
 141 static ssize_t show_sampling_rate_max(struct cpufreq_policy *policy, char *buf)
 142 {
 143         static int print_once;
 144
 145         if (!print_once) {
 146                 printk(KERN_INFO "CPUFREQ: conservative sampling_rate_max "
 147                        "sysfs file is deprecated - used by: %s\n",
 148                        current->comm);
 149                 print_once = 1;
 150         }
 151         return sprintf(buf, "%u\n", MAX_SAMPLING_RATE);
 152 }
 153
 154 static ssize_t show_sampling_rate_min(struct cpufreq_policy *policy, char *buf)
 155 {
 156         static int print_once;
 157
 158         if (!print_once) {
 159                 printk(KERN_INFO "CPUFREQ: conservative sampling_rate_max "
 160                        "sysfs file is deprecated - used by: %s\n", current->comm);
 161                 print_once = 1;
 162         }
 163         return sprintf(buf, "%u\n", MIN_SAMPLING_RATE);
 164 }
 165
 166 #define define_one_ro(_name)                            \
 167 static struct freq_attr _name =                         \
 168 __ATTR(_name, 0444, show_##_name, NULL)
 169
 170 define_one_ro(sampling_rate_max);
 171 define_one_ro(sampling_rate_min);
 172
 173 /* cpufreq_conservative Governor Tunables */
 174 #define show_one(file_name, object)                                     \
 175 static ssize_t show_##file_name                                         \
 176 (struct cpufreq_policy *unused, char *buf)                              \
 177 {                                                                       \
 178         return sprintf(buf, "%u\n", dbs_tuners_ins.object);             \
 179 }
 180 show_one(sampling_rate, sampling_rate);
 181 show_one(sampling_down_factor, sampling_down_factor);
 182 show_one(up_threshold, up_threshold);
 183 show_one(down_threshold, down_threshold);
 184 show_one(ignore_nice_load, ignore_nice);
 185 show_one(freq_step, freq_step);
 186
 187 static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused,
 188                 const char *buf, size_t count)
 189 {
 190         unsigned int input;
 191         int ret;
 192         ret = sscanf(buf, "%u", &input);
 193         if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1)
 194                 return -EINVAL;
 195
 196         mutex_lock(&dbs_mutex);
 197         dbs_tuners_ins.sampling_down_factor = input;
 198         mutex_unlock(&dbs_mutex);
 199
 200         return count;
 201 }
 202
 203 static ssize_t store_sampling_rate(struct cpufreq_policy *unused,
 204                 const char *buf, size_t count)
 205 {
 206         unsigned int input;
 207         int ret;
 208         ret = sscanf(buf, "%u", &input);
 209
 210         mutex_lock(&dbs_mutex);
 211         if (ret != 1 || input > MAX_SAMPLING_RATE ||
 212             input < MIN_SAMPLING_RATE) {
 213                 mutex_unlock(&dbs_mutex);
 214                 return -EINVAL;
 215         }
 216
 217         dbs_tuners_ins.sampling_rate = input;
 218         mutex_unlock(&dbs_mutex);
 219
 220         return count;
 221 }
 222
 223 static ssize_t store_up_threshold(struct cpufreq_policy *unused,
 224                 const char *buf, size_t count)
 225 {
 226         unsigned int input;
 227         int ret;
 228         ret = sscanf(buf, "%u", &input);
 229
 230         mutex_lock(&dbs_mutex);
 231         if (ret != 1 || input > 100 ||
 232             input <= dbs_tuners_ins.down_threshold) {
 233                 mutex_unlock(&dbs_mutex);
 234                 return -EINVAL;
 235         }
 236
 237         dbs_tuners_ins.up_threshold = input;
 238         mutex_unlock(&dbs_mutex);
 239
 240         return count;
 241 }
 242
 243 static ssize_t store_down_threshold(struct cpufreq_policy *unused,
 244                 const char *buf, size_t count)
 245 {
 246         unsigned int input;
 247         int ret;
 248         ret = sscanf(buf, "%u", &input);
 249
 250         mutex_lock(&dbs_mutex);
 251         if (ret != 1 || input > 100 || input >= dbs_tuners_ins.up_threshold) {
 252                 mutex_unlock(&dbs_mutex);
 253                 return -EINVAL;
 254         }
 255
 256         dbs_tuners_ins.down_threshold = input;
 257         mutex_unlock(&dbs_mutex);
 258
 259         return count;
 260 }
 261
 262 static ssize_t store_ignore_nice_load(struct cpufreq_policy *policy,
 263                 const char *buf, size_t count)
 264 {
 265         unsigned int input;
 266         int ret;
 267
 268         unsigned int j;
 269
 270         ret = sscanf(buf, "%u", &input);
 271         if (ret != 1)
 272                 return -EINVAL;
 273
 274         if (input > 1)
 275                 input = 1;
 276
 277         mutex_lock(&dbs_mutex);
 278         if (input == dbs_tuners_ins.ignore_nice) { /* nothing to do */
 279                 mutex_unlock(&dbs_mutex);
 280                 return count;
 281         }
 282         dbs_tuners_ins.ignore_nice = input;
 283
 284         /* we need to re-evaluate prev_cpu_idle_up and prev_cpu_idle_down */
 285         for_each_online_cpu(j) {
 286                 struct cpu_dbs_info_s *j_dbs_info;
 287                 j_dbs_info = &per_cpu(cpu_dbs_info, j);
 288                 j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(j);
 289                 j_dbs_info->prev_cpu_idle_down = j_dbs_info->prev_cpu_idle_up;
 290         }
 291         mutex_unlock(&dbs_mutex);
 292
 293         return count;
 294 }
 295
 296 static ssize_t store_freq_step(struct cpufreq_policy *policy,
 297                 const char *buf, size_t count)
 298 {
 299         unsigned int input;
 300         int ret;
 301
 302         ret = sscanf(buf, "%u", &input);
 303
 304         if (ret != 1)
 305                 return -EINVAL;
 306
 307         if (input > 100)
 308                 input = 100;
 309
 310         /* no need to test here if freq_step is zero as the user might actually
 311          * want this, they would be crazy though :) */
 312         mutex_lock(&dbs_mutex);
 313         dbs_tuners_ins.freq_step = input;
 314         mutex_unlock(&dbs_mutex);
 315
 316         return count;
 317 }
 318
 319 #define define_one_rw(_name) \
 320 static struct freq_attr _name = \
 321 __ATTR(_name, 0644, show_##_name, store_##_name)
 322
 323 define_one_rw(sampling_rate);
 324 define_one_rw(sampling_down_factor);
 325 define_one_rw(up_threshold);
 326 define_one_rw(down_threshold);
 327 define_one_rw(ignore_nice_load);
 328 define_one_rw(freq_step);
 329
 330 static struct attribute *dbs_attributes[] = {
 331         &sampling_rate_max.attr,
 332         &sampling_rate_min.attr,
 333         &sampling_rate.attr,
 334         &sampling_down_factor.attr,
 335         &up_threshold.attr,
 336         &down_threshold.attr,
 337         &ignore_nice_load.attr,
 338         &freq_step.attr,
 339         NULL
 340 };
 341
 342 static struct attribute_group dbs_attr_group = {
 343         .attrs = dbs_attributes,
 344         .name = "conservative",
 345 };
 346
 347 /************************** sysfs end ************************/
 348
 349 static void dbs_check_cpu(int cpu)
 350 {
 351         unsigned int idle_ticks, up_idle_ticks, down_idle_ticks;
 352         unsigned int tmp_idle_ticks, total_idle_ticks;
 353         unsigned int freq_target;
 354         unsigned int freq_down_sampling_rate;
 355         struct cpu_dbs_info_s *this_dbs_info = &per_cpu(cpu_dbs_info, cpu);
 356         struct cpufreq_policy *policy;
 357
 358         if (!this_dbs_info->enable)
 359                 return;
 360
 361         policy = this_dbs_info->cur_policy;
 362
 363         /*
 364          * The default safe range is 20% to 80%
 365          * Every sampling_rate, we check
 366          *      - If current idle time is less than 20%, then we try to
 367          *        increase frequency
 368          * Every sampling_rate*sampling_down_factor, we check
 369          *      - If current idle time is more than 80%, then we try to
 370          *        decrease frequency
 371          *
 372          * Any frequency increase takes it to the maximum frequency.
 373          * Frequency reduction happens at minimum steps of
 374          * 5% (default) of max_frequency
 375          */
 376
 377         /* Check for frequency increase */
 378         idle_ticks = UINT_MAX;
 379
 380         /* Check for frequency increase */
 381         total_idle_ticks = get_cpu_idle_time(cpu);
 382         tmp_idle_ticks = total_idle_ticks -
 383                 this_dbs_info->prev_cpu_idle_up;
 384         this_dbs_info->prev_cpu_idle_up = total_idle_ticks;
 385
 386         if (tmp_idle_ticks < idle_ticks)
 387                 idle_ticks = tmp_idle_ticks;
 388
 389         /* Scale idle ticks by 100 and compare with up and down ticks */
 390         idle_ticks *= 100;
 391         up_idle_ticks = (100 - dbs_tuners_ins.up_threshold) *
 392                         usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
 393
 394         if (idle_ticks < up_idle_ticks) {
 395                 this_dbs_info->down_skip = 0;
 396                 this_dbs_info->prev_cpu_idle_down =
 397                         this_dbs_info->prev_cpu_idle_up;
 398
 399                 /* if we are already at full speed then break out early */
 400                 if (this_dbs_info->requested_freq == policy->max)
 401                         return;
 402
 403                 freq_target = (dbs_tuners_ins.freq_step * policy->max) / 100;
 404
 405                 /* max freq cannot be less than 100. But who knows.... */
 406                 if (unlikely(freq_target == 0))
 407                         freq_target = 5;
 408
 409                 this_dbs_info->requested_freq += freq_target;
 410                 if (this_dbs_info->requested_freq > policy->max)
 411                         this_dbs_info->requested_freq = policy->max;
 412
 413                 __cpufreq_driver_target(policy, this_dbs_info->requested_freq,
 414                         CPUFREQ_RELATION_H);
 415                 return;
 416         }
 417
 418         /* Check for frequency decrease */
 419         this_dbs_info->down_skip++;
 420         if (this_dbs_info->down_skip < dbs_tuners_ins.sampling_down_factor)
 421                 return;
 422
 423         /* Check for frequency decrease */
 424         total_idle_ticks = this_dbs_info->prev_cpu_idle_up;
 425         tmp_idle_ticks = total_idle_ticks -
 426                 this_dbs_info->prev_cpu_idle_down;
 427         this_dbs_info->prev_cpu_idle_down = total_idle_ticks;
 428
 429         if (tmp_idle_ticks < idle_ticks)
 430                 idle_ticks = tmp_idle_ticks;
 431
 432         /* Scale idle ticks by 100 and compare with up and down ticks */
 433         idle_ticks *= 100;
 434         this_dbs_info->down_skip = 0;
 435
 436         freq_down_sampling_rate = dbs_tuners_ins.sampling_rate *
 437                 dbs_tuners_ins.sampling_down_factor;
 438         down_idle_ticks = (100 - dbs_tuners_ins.down_threshold) *
 439                 usecs_to_jiffies(freq_down_sampling_rate);
 440
 441         if (idle_ticks > down_idle_ticks) {
 442                 /*
 443                  * if we are already at the lowest speed then break out early
 444                  * or if we 'cannot' reduce the speed as the user might want
 445                  * freq_target to be zero
 446                  */
 447                 if (this_dbs_info->requested_freq == policy->min
 448                                 || dbs_tuners_ins.freq_step == 0)
 449                         return;
 450
 451                 freq_target = (dbs_tuners_ins.freq_step * policy->max) / 100;
 452
 453                 /* max freq cannot be less than 100. But who knows.... */
 454                 if (unlikely(freq_target == 0))
 455                         freq_target = 5;
 456
 457                 this_dbs_info->requested_freq -= freq_target;
 458                 if (this_dbs_info->requested_freq < policy->min)
 459                         this_dbs_info->requested_freq = policy->min;
 460
 461                 __cpufreq_driver_target(policy, this_dbs_info->requested_freq,
 462                                 CPUFREQ_RELATION_H);
 463                 return;
 464         }
 465 }
 466
 467 static void do_dbs_timer(struct work_struct *work)
 468 {
 469         int i;
 470         mutex_lock(&dbs_mutex);
 471         for_each_online_cpu(i)
 472                 dbs_check_cpu(i);
 473         schedule_delayed_work(&dbs_work,
 474                         usecs_to_jiffies(dbs_tuners_ins.sampling_rate));
 475         mutex_unlock(&dbs_mutex);
 476 }
 477
 478 static inline void dbs_timer_init(void)
 479 {
 480         init_timer_deferrable(&dbs_work.timer);
 481         schedule_delayed_work(&dbs_work,
 482                         usecs_to_jiffies(dbs_tuners_ins.sampling_rate));
 483         return;
 484 }
 485
 486 static inline void dbs_timer_exit(void)
 487 {
 488         cancel_delayed_work(&dbs_work);
 489         return;
 490 }
 491
 492 static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 493                                    unsigned int event)
 494 {
 495         unsigned int cpu = policy->cpu;
 496         struct cpu_dbs_info_s *this_dbs_info;
 497         unsigned int j;
 498         int rc;
 499
 500         this_dbs_info = &per_cpu(cpu_dbs_info, cpu);
 501
 502         switch (event) {
 503         case CPUFREQ_GOV_START:
 504                 if ((!cpu_online(cpu)) || (!policy->cur))
 505                         return -EINVAL;
 506
 507                 if (this_dbs_info->enable) /* Already enabled */
 508                         break;
 509
 510                 mutex_lock(&dbs_mutex);
 511
 512                 rc = sysfs_create_group(&policy->kobj, &dbs_attr_group);
 513                 if (rc) {
 514                         mutex_unlock(&dbs_mutex);
 515                         return rc;
 516                 }
 517
 518                 for_each_cpu(j, policy->cpus) {
 519                         struct cpu_dbs_info_s *j_dbs_info;
 520                         j_dbs_info = &per_cpu(cpu_dbs_info, j);
 521                         j_dbs_info->cur_policy = policy;
 522
 523                         j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(cpu);
 524                         j_dbs_info->prev_cpu_idle_down
 525                                 = j_dbs_info->prev_cpu_idle_up;
 526                 }
 527                 this_dbs_info->enable = 1;
 528                 this_dbs_info->down_skip = 0;
 529                 this_dbs_info->requested_freq = policy->cur;
 530
 531                 dbs_enable++;
 532                 /*
 533                  * Start the timerschedule work, when this governor
 534                  * is used for first time
 535                  */
 536                 if (dbs_enable == 1) {
 537                         unsigned int latency;
 538                         /* policy latency is in nS. Convert it to uS first */
 539                         latency = policy->cpuinfo.transition_latency / 1000;
 540                         if (latency == 0)
 541                                 latency = 1;
 542
 543                         def_sampling_rate = 10 * latency *
 544                                         DEF_SAMPLING_RATE_LATENCY_MULTIPLIER;
 545
 546                         if (def_sampling_rate < MIN_STAT_SAMPLING_RATE)
 547                                 def_sampling_rate = MIN_STAT_SAMPLING_RATE;
 548
 549                         dbs_tuners_ins.sampling_rate = def_sampling_rate;
 550
 551                         dbs_timer_init();
 552                         cpufreq_register_notifier(
 553                                         &dbs_cpufreq_notifier_block,
 554                                         CPUFREQ_TRANSITION_NOTIFIER);
 555                 }
 556
 557                 mutex_unlock(&dbs_mutex);
 558                 break;
 559
 560         case CPUFREQ_GOV_STOP:
 561                 mutex_lock(&dbs_mutex);
 562                 this_dbs_info->enable = 0;
 563                 sysfs_remove_group(&policy->kobj, &dbs_attr_group);
 564                 dbs_enable--;
 565                 /*
 566                  * Stop the timerschedule work, when this governor
 567                  * is used for first time
 568                  */
 569                 if (dbs_enable == 0) {
 570                         dbs_timer_exit();
 571                         cpufreq_unregister_notifier(
 572                                         &dbs_cpufreq_notifier_block,
 573                                         CPUFREQ_TRANSITION_NOTIFIER);
 574                 }
 575
 576                 mutex_unlock(&dbs_mutex);
 577
 578                 break;
 579
 580         case CPUFREQ_GOV_LIMITS:
 581                 mutex_lock(&dbs_mutex);
 582                 if (policy->max < this_dbs_info->cur_policy->cur)
 583                         __cpufreq_driver_target(
 584                                         this_dbs_info->cur_policy,
 585                                         policy->max, CPUFREQ_RELATION_H);
 586                 else if (policy->min > this_dbs_info->cur_policy->cur)
 587                         __cpufreq_driver_target(
 588                                         this_dbs_info->cur_policy,
 589                                         policy->min, CPUFREQ_RELATION_L);
 590                 mutex_unlock(&dbs_mutex);
 591                 break;
 592         }
 593         return 0;
 594 }
 595
 596 #ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
 597 static
 598 #endif
 599 struct cpufreq_governor cpufreq_gov_conservative = {
 600         .name                   = "conservative",
 601         .governor               = cpufreq_governor_dbs,
 602         .max_transition_latency = TRANSITION_LATENCY_LIMIT,
 603         .owner                  = THIS_MODULE,
 604 };
 605
 606 static int __init cpufreq_gov_dbs_init(void)
 607 {
 608         return cpufreq_register_governor(&cpufreq_gov_conservative);
 609 }
 610
 611 static void __exit cpufreq_gov_dbs_exit(void)
 612 {
 613         /* Make sure that the scheduled work is indeed not running */
 614         flush_scheduled_work();
 615
 616         cpufreq_unregister_governor(&cpufreq_gov_conservative);
 617 }
 618
 619
 620 MODULE_AUTHOR("Alexander Clouter <alex-kernel@digriz.org.uk>");
 621 MODULE_DESCRIPTION("'cpufreq_conservative' - A dynamic cpufreq governor for "
 622                 "Low Latency Frequency Transition capable processors "
 623                 "optimised for use in a battery environment");
 624 MODULE_LICENSE("GPL");
 625
 626 #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
 627 fs_initcall(cpufreq_gov_dbs_init);
 628 #else
 629 module_init(cpufreq_gov_dbs_init);
 630 #endif
 631 module_exit(cpufreq_gov_dbs_exit);