drivers/cpufreq/cpufreq_interactive.c

   1 /*
   2  * drivers/cpufreq/cpufreq_interactive.c
   3  *
   4  * Copyright (C) 2010 Google, Inc.
   5  *
   6  * This software is licensed under the terms of the GNU General Public
   7  * License version 2, as published by the Free Software Foundation, and
   8  * may be copied, distributed, and modified under those terms.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * Author: Mike Chan (mike@android.com)
  16  *
  17  */
  18
  19 #include <linux/cpu.h>
  20 #include <linux/cpumask.h>
  21 #include <linux/cpufreq.h>
  22 #include <linux/mutex.h>
  23 #include <linux/sched.h>
  24 #include <linux/tick.h>
  25 #include <linux/time.h>
  26 #include <linux/timer.h>
  27 #include <linux/workqueue.h>
  28 #include <linux/kthread.h>
  29 #include <linux/mutex.h>
  30
  31 #include <asm/cputime.h>
  32
  33 static atomic_t active_count = ATOMIC_INIT(0);
  34
  35 struct cpufreq_interactive_cpuinfo {
  36         struct timer_list cpu_timer;
  37         int timer_idlecancel;
  38         u64 time_in_idle;
  39         u64 idle_exit_time;
  40         u64 timer_run_time;
  41         int idling;
  42         u64 freq_change_time;
  43         u64 freq_change_time_in_idle;
  44         struct cpufreq_policy *policy;
  45         struct cpufreq_frequency_table *freq_table;
  46         unsigned int target_freq;
  47         int governor_enabled;
  48 };
  49
  50 static DEFINE_PER_CPU(struct cpufreq_interactive_cpuinfo, cpuinfo);
  51
  52 /* Workqueues handle frequency scaling */
  53 static struct task_struct *up_task;
  54 static struct workqueue_struct *down_wq;
  55 static struct work_struct freq_scale_down_work;
  56 static cpumask_t up_cpumask;
  57 static spinlock_t up_cpumask_lock;
  58 static cpumask_t down_cpumask;
  59 static spinlock_t down_cpumask_lock;
  60 static struct mutex set_speed_lock;
  61
  62 /* Hi speed to bump to from lo speed when load burst (default max) */
  63 static u64 hispeed_freq;
  64
  65 /* Go to hi speed when CPU load at or above this value. */
  66 #define DEFAULT_GO_HISPEED_LOAD 95
  67 static unsigned long go_hispeed_load;
  68
  69 /*
  70  * The minimum amount of time to spend at a frequency before we can ramp down.
  71  */
  72 #define DEFAULT_MIN_SAMPLE_TIME 20 * USEC_PER_MSEC
  73 static unsigned long min_sample_time;
  74
  75 /*
  76  * The sample rate of the timer used to increase frequency
  77  */
  78 #define DEFAULT_TIMER_RATE 20 * USEC_PER_MSEC
  79 static unsigned long timer_rate;
  80
  81 static int cpufreq_governor_interactive(struct cpufreq_policy *policy,
  82                 unsigned int event);
  83
  84 #ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_INTERACTIVE
  85 static
  86 #endif
  87 struct cpufreq_governor cpufreq_gov_interactive = {
  88         .name = "interactive",
  89         .governor = cpufreq_governor_interactive,
  90         .max_transition_latency = 10000000,
  91         .owner = THIS_MODULE,
  92 };
  93
  94 static void cpufreq_interactive_timer(unsigned long data)
  95 {
  96         unsigned int delta_idle;
  97         unsigned int delta_time;
  98         int cpu_load;
  99         int load_since_change;
 100         u64 time_in_idle;
 101         u64 idle_exit_time;
 102         struct cpufreq_interactive_cpuinfo *pcpu =
 103                 &per_cpu(cpuinfo, data);
 104         u64 now_idle;
 105         unsigned int new_freq;
 106         unsigned int index;
 107         unsigned long flags;
 108
 109         smp_rmb();
 110
 111         if (!pcpu->governor_enabled)
 112                 goto exit;
 113
 114         /*
 115          * Once pcpu->timer_run_time is updated to >= pcpu->idle_exit_time,
 116          * this lets idle exit know the current idle time sample has
 117          * been processed, and idle exit can generate a new sample and
 118          * re-arm the timer.  This prevents a concurrent idle
 119          * exit on that CPU from writing a new set of info at the same time
 120          * the timer function runs (the timer function can't use that info
 121          * until more time passes).
 122          */
 123         time_in_idle = pcpu->time_in_idle;
 124         idle_exit_time = pcpu->idle_exit_time;
 125         now_idle = get_cpu_idle_time_us(data, &pcpu->timer_run_time);
 126         smp_wmb();
 127
 128         /* If we raced with cancelling a timer, skip. */
 129         if (!idle_exit_time)
 130                 goto exit;
 131
 132         delta_idle = (unsigned int) cputime64_sub(now_idle, time_in_idle);
 133         delta_time = (unsigned int) cputime64_sub(pcpu->timer_run_time,
 134                                                   idle_exit_time);
 135
 136         /*
 137          * If timer ran less than 1ms after short-term sample started, retry.
 138          */
 139         if (delta_time < 1000)
 140                 goto rearm;
 141
 142         if (delta_idle > delta_time)
 143                 cpu_load = 0;
 144         else
 145                 cpu_load = 100 * (delta_time - delta_idle) / delta_time;
 146
 147         delta_idle = (unsigned int) cputime64_sub(now_idle,
 148                                                 pcpu->freq_change_time_in_idle);
 149         delta_time = (unsigned int) cputime64_sub(pcpu->timer_run_time,
 150                                                   pcpu->freq_change_time);
 151
 152         if ((delta_time == 0) || (delta_idle > delta_time))
 153                 load_since_change = 0;
 154         else
 155                 load_since_change =
 156                         100 * (delta_time - delta_idle) / delta_time;
 157
 158         /*
 159          * Choose greater of short-term load (since last idle timer
 160          * started or timer function re-armed itself) or long-term load
 161          * (since last frequency change).
 162          */
 163         if (load_since_change > cpu_load)
 164                 cpu_load = load_since_change;
 165
 166         if (cpu_load >= go_hispeed_load) {
 167                 if (pcpu->policy->cur == pcpu->policy->min)
 168                         new_freq = hispeed_freq;
 169                 else
 170                         new_freq = pcpu->policy->max * cpu_load / 100;
 171         } else {
 172                 new_freq = pcpu->policy->cur * cpu_load / 100;
 173         }
 174
 175         if (cpufreq_frequency_table_target(pcpu->policy, pcpu->freq_table,
 176                                            new_freq, CPUFREQ_RELATION_H,
 177                                            &index)) {
 178                 pr_warn_once("timer %d: cpufreq_frequency_table_target error\n",
 179                              (int) data);
 180                 goto rearm;
 181         }
 182
 183         new_freq = pcpu->freq_table[index].frequency;
 184
 185         if (pcpu->target_freq == new_freq)
 186                 goto rearm_if_notmax;
 187
 188         /*
 189          * Do not scale down unless we have been at this frequency for the
 190          * minimum sample time.
 191          */
 192         if (new_freq < pcpu->target_freq) {
 193                 if (cputime64_sub(pcpu->timer_run_time, pcpu->freq_change_time)
 194                     < min_sample_time)
 195                         goto rearm;
 196         }
 197
 198         if (new_freq < pcpu->target_freq) {
 199                 pcpu->target_freq = new_freq;
 200                 spin_lock_irqsave(&down_cpumask_lock, flags);
 201                 cpumask_set_cpu(data, &down_cpumask);
 202                 spin_unlock_irqrestore(&down_cpumask_lock, flags);
 203                 queue_work(down_wq, &freq_scale_down_work);
 204         } else {
 205                 pcpu->target_freq = new_freq;
 206                 spin_lock_irqsave(&up_cpumask_lock, flags);
 207                 cpumask_set_cpu(data, &up_cpumask);
 208                 spin_unlock_irqrestore(&up_cpumask_lock, flags);
 209                 wake_up_process(up_task);
 210         }
 211
 212 rearm_if_notmax:
 213         /*
 214          * Already set max speed and don't see a need to change that,
 215          * wait until next idle to re-evaluate, don't need timer.
 216          */
 217         if (pcpu->target_freq == pcpu->policy->max)
 218                 goto exit;
 219
 220 rearm:
 221         if (!timer_pending(&pcpu->cpu_timer)) {
 222                 /*
 223                  * If already at min: if that CPU is idle, don't set timer.
 224                  * Else cancel the timer if that CPU goes idle.  We don't
 225                  * need to re-evaluate speed until the next idle exit.
 226                  */
 227                 if (pcpu->target_freq == pcpu->policy->min) {
 228                         smp_rmb();
 229
 230                         if (pcpu->idling)
 231                                 goto exit;
 232
 233                         pcpu->timer_idlecancel = 1;
 234                 }
 235
 236                 pcpu->time_in_idle = get_cpu_idle_time_us(
 237                         data, &pcpu->idle_exit_time);
 238                 mod_timer(&pcpu->cpu_timer,
 239                           jiffies + usecs_to_jiffies(timer_rate));
 240         }
 241
 242 exit:
 243         return;
 244 }
 245
 246 static void cpufreq_interactive_idle_start(void)
 247 {
 248         struct cpufreq_interactive_cpuinfo *pcpu =
 249                 &per_cpu(cpuinfo, smp_processor_id());
 250         int pending;
 251
 252         if (!pcpu->governor_enabled)
 253                 return;
 254
 255         pcpu->idling = 1;
 256         smp_wmb();
 257         pending = timer_pending(&pcpu->cpu_timer);
 258
 259         if (pcpu->target_freq != pcpu->policy->min) {
 260 #ifdef CONFIG_SMP
 261                 /*
 262                  * Entering idle while not at lowest speed.  On some
 263                  * platforms this can hold the other CPU(s) at that speed
 264                  * even though the CPU is idle. Set a timer to re-evaluate
 265                  * speed so this idle CPU doesn't hold the other CPUs above
 266                  * min indefinitely.  This should probably be a quirk of
 267                  * the CPUFreq driver.
 268                  */
 269                 if (!pending) {
 270                         pcpu->time_in_idle = get_cpu_idle_time_us(
 271                                 smp_processor_id(), &pcpu->idle_exit_time);
 272                         pcpu->timer_idlecancel = 0;
 273                         mod_timer(&pcpu->cpu_timer,
 274                                   jiffies + usecs_to_jiffies(timer_rate));
 275                 }
 276 #endif
 277         } else {
 278                 /*
 279                  * If at min speed and entering idle after load has
 280                  * already been evaluated, and a timer has been set just in
 281                  * case the CPU suddenly goes busy, cancel that timer.  The
 282                  * CPU didn't go busy; we'll recheck things upon idle exit.
 283                  */
 284                 if (pending && pcpu->timer_idlecancel) {
 285                         del_timer(&pcpu->cpu_timer);
 286                         /*
 287                          * Ensure last timer run time is after current idle
 288                          * sample start time, so next idle exit will always
 289                          * start a new idle sampling period.
 290                          */
 291                         pcpu->idle_exit_time = 0;
 292                         pcpu->timer_idlecancel = 0;
 293                 }
 294         }
 295
 296 }
 297
 298 static void cpufreq_interactive_idle_end(void)
 299 {
 300         struct cpufreq_interactive_cpuinfo *pcpu =
 301                 &per_cpu(cpuinfo, smp_processor_id());
 302
 303         pcpu->idling = 0;
 304         smp_wmb();
 305
 306         /*
 307          * Arm the timer for 1-2 ticks later if not already, and if the timer
 308          * function has already processed the previous load sampling
 309          * interval.  (If the timer is not pending but has not processed
 310          * the previous interval, it is probably racing with us on another
 311          * CPU.  Let it compute load based on the previous sample and then
 312          * re-arm the timer for another interval when it's done, rather
 313          * than updating the interval start time to be "now", which doesn't
 314          * give the timer function enough time to make a decision on this
 315          * run.)
 316          */
 317         if (timer_pending(&pcpu->cpu_timer) == 0 &&
 318             pcpu->timer_run_time >= pcpu->idle_exit_time &&
 319             pcpu->governor_enabled) {
 320                 pcpu->time_in_idle =
 321                         get_cpu_idle_time_us(smp_processor_id(),
 322                                              &pcpu->idle_exit_time);
 323                 pcpu->timer_idlecancel = 0;
 324                 mod_timer(&pcpu->cpu_timer,
 325                           jiffies + usecs_to_jiffies(timer_rate));
 326         }
 327
 328 }
 329
 330 static int cpufreq_interactive_up_task(void *data)
 331 {
 332         unsigned int cpu;
 333         cpumask_t tmp_mask;
 334         unsigned long flags;
 335         struct cpufreq_interactive_cpuinfo *pcpu;
 336
 337         while (1) {
 338                 set_current_state(TASK_INTERRUPTIBLE);
 339                 spin_lock_irqsave(&up_cpumask_lock, flags);
 340
 341                 if (cpumask_empty(&up_cpumask)) {
 342                         spin_unlock_irqrestore(&up_cpumask_lock, flags);
 343                         schedule();
 344
 345                         if (kthread_should_stop())
 346                                 break;
 347
 348                         spin_lock_irqsave(&up_cpumask_lock, flags);
 349                 }
 350
 351                 set_current_state(TASK_RUNNING);
 352                 tmp_mask = up_cpumask;
 353                 cpumask_clear(&up_cpumask);
 354                 spin_unlock_irqrestore(&up_cpumask_lock, flags);
 355
 356                 for_each_cpu(cpu, &tmp_mask) {
 357                         unsigned int j;
 358                         unsigned int max_freq = 0;
 359
 360                         pcpu = &per_cpu(cpuinfo, cpu);
 361                         smp_rmb();
 362
 363                         if (!pcpu->governor_enabled)
 364                                 continue;
 365
 366                         mutex_lock(&set_speed_lock);
 367
 368                         for_each_cpu(j, pcpu->policy->cpus) {
 369                                 struct cpufreq_interactive_cpuinfo *pjcpu =
 370                                         &per_cpu(cpuinfo, j);
 371
 372                                 if (pjcpu->target_freq > max_freq)
 373                                         max_freq = pjcpu->target_freq;
 374                         }
 375
 376                         if (max_freq != pcpu->policy->cur)
 377                                 __cpufreq_driver_target(pcpu->policy,
 378                                                         max_freq,
 379                                                         CPUFREQ_RELATION_H);
 380                         mutex_unlock(&set_speed_lock);
 381
 382                         pcpu->freq_change_time_in_idle =
 383                                 get_cpu_idle_time_us(cpu,
 384                                                      &pcpu->freq_change_time);
 385                 }
 386         }
 387
 388         return 0;
 389 }
 390
 391 static void cpufreq_interactive_freq_down(struct work_struct *work)
 392 {
 393         unsigned int cpu;
 394         cpumask_t tmp_mask;
 395         unsigned long flags;
 396         struct cpufreq_interactive_cpuinfo *pcpu;
 397
 398         spin_lock_irqsave(&down_cpumask_lock, flags);
 399         tmp_mask = down_cpumask;
 400         cpumask_clear(&down_cpumask);
 401         spin_unlock_irqrestore(&down_cpumask_lock, flags);
 402
 403         for_each_cpu(cpu, &tmp_mask) {
 404                 unsigned int j;
 405                 unsigned int max_freq = 0;
 406
 407                 pcpu = &per_cpu(cpuinfo, cpu);
 408                 smp_rmb();
 409
 410                 if (!pcpu->governor_enabled)
 411                         continue;
 412
 413                 mutex_lock(&set_speed_lock);
 414
 415                 for_each_cpu(j, pcpu->policy->cpus) {
 416                         struct cpufreq_interactive_cpuinfo *pjcpu =
 417                                 &per_cpu(cpuinfo, j);
 418
 419                         if (pjcpu->target_freq > max_freq)
 420                                 max_freq = pjcpu->target_freq;
 421                 }
 422
 423                 if (max_freq != pcpu->policy->cur)
 424                         __cpufreq_driver_target(pcpu->policy, max_freq,
 425                                                 CPUFREQ_RELATION_H);
 426
 427                 mutex_unlock(&set_speed_lock);
 428                 pcpu->freq_change_time_in_idle =
 429                         get_cpu_idle_time_us(cpu,
 430                                              &pcpu->freq_change_time);
 431         }
 432 }
 433
 434 static ssize_t show_hispeed_freq(struct kobject *kobj,
 435                                  struct attribute *attr, char *buf)
 436 {
 437         return sprintf(buf, "%llu\n", hispeed_freq);
 438 }
 439
 440 static ssize_t store_hispeed_freq(struct kobject *kobj,
 441                                   struct attribute *attr, const char *buf,
 442                                   size_t count)
 443 {
 444         int ret;
 445         u64 val;
 446
 447         ret = strict_strtoull(buf, 0, &val);
 448         if (ret < 0)
 449                 return ret;
 450         hispeed_freq = val;
 451         return count;
 452 }
 453
 454 static struct global_attr hispeed_freq_attr = __ATTR(hispeed_freq, 0644,
 455                 show_hispeed_freq, store_hispeed_freq);
 456
 457
 458 static ssize_t show_go_hispeed_load(struct kobject *kobj,
 459                                      struct attribute *attr, char *buf)
 460 {
 461         return sprintf(buf, "%lu\n", go_hispeed_load);
 462 }
 463
 464 static ssize_t store_go_hispeed_load(struct kobject *kobj,
 465                         struct attribute *attr, const char *buf, size_t count)
 466 {
 467         int ret;
 468         unsigned long val;
 469
 470         ret = strict_strtoul(buf, 0, &val);
 471         if (ret < 0)
 472                 return ret;
 473         go_hispeed_load = val;
 474         return count;
 475 }
 476
 477 static struct global_attr go_hispeed_load_attr = __ATTR(go_hispeed_load, 0644,
 478                 show_go_hispeed_load, store_go_hispeed_load);
 479
 480 static ssize_t show_min_sample_time(struct kobject *kobj,
 481                                 struct attribute *attr, char *buf)
 482 {
 483         return sprintf(buf, "%lu\n", min_sample_time);
 484 }
 485
 486 static ssize_t store_min_sample_time(struct kobject *kobj,
 487                         struct attribute *attr, const char *buf, size_t count)
 488 {
 489         int ret;
 490         unsigned long val;
 491
 492         ret = strict_strtoul(buf, 0, &val);
 493         if (ret < 0)
 494                 return ret;
 495         min_sample_time = val;
 496         return count;
 497 }
 498
 499 static struct global_attr min_sample_time_attr = __ATTR(min_sample_time, 0644,
 500                 show_min_sample_time, store_min_sample_time);
 501
 502 static ssize_t show_timer_rate(struct kobject *kobj,
 503                         struct attribute *attr, char *buf)
 504 {
 505         return sprintf(buf, "%lu\n", timer_rate);
 506 }
 507
 508 static ssize_t store_timer_rate(struct kobject *kobj,
 509                         struct attribute *attr, const char *buf, size_t count)
 510 {
 511         int ret;
 512         unsigned long val;
 513
 514         ret = strict_strtoul(buf, 0, &val);
 515         if (ret < 0)
 516                 return ret;
 517         timer_rate = val;
 518         return count;
 519 }
 520
 521 static struct global_attr timer_rate_attr = __ATTR(timer_rate, 0644,
 522                 show_timer_rate, store_timer_rate);
 523
 524 static struct attribute *interactive_attributes[] = {
 525         &hispeed_freq_attr.attr,
 526         &go_hispeed_load_attr.attr,
 527         &min_sample_time_attr.attr,
 528         &timer_rate_attr.attr,
 529         NULL,
 530 };
 531
 532 static struct attribute_group interactive_attr_group = {
 533         .attrs = interactive_attributes,
 534         .name = "interactive",
 535 };
 536
 537 static int cpufreq_governor_interactive(struct cpufreq_policy *policy,
 538                 unsigned int event)
 539 {
 540         int rc;
 541         unsigned int j;
 542         struct cpufreq_interactive_cpuinfo *pcpu;
 543         struct cpufreq_frequency_table *freq_table;
 544
 545         switch (event) {
 546         case CPUFREQ_GOV_START:
 547                 if (!cpu_online(policy->cpu))
 548                         return -EINVAL;
 549
 550                 freq_table =
 551                         cpufreq_frequency_get_table(policy->cpu);
 552
 553                 for_each_cpu(j, policy->cpus) {
 554                         pcpu = &per_cpu(cpuinfo, j);
 555                         pcpu->policy = policy;
 556                         pcpu->target_freq = policy->cur;
 557                         pcpu->freq_table = freq_table;
 558                         pcpu->freq_change_time_in_idle =
 559                                 get_cpu_idle_time_us(j,
 560                                              &pcpu->freq_change_time);
 561                         pcpu->governor_enabled = 1;
 562                         smp_wmb();
 563                 }
 564
 565                 if (!hispeed_freq)
 566                         hispeed_freq = policy->max;
 567
 568                 /*
 569                  * Do not register the idle hook and create sysfs
 570                  * entries if we have already done so.
 571                  */
 572                 if (atomic_inc_return(&active_count) > 1)
 573                         return 0;
 574
 575                 rc = sysfs_create_group(cpufreq_global_kobject,
 576                                 &interactive_attr_group);
 577                 if (rc)
 578                         return rc;
 579
 580                 break;
 581
 582         case CPUFREQ_GOV_STOP:
 583                 for_each_cpu(j, policy->cpus) {
 584                         pcpu = &per_cpu(cpuinfo, j);
 585                         pcpu->governor_enabled = 0;
 586                         smp_wmb();
 587                         del_timer_sync(&pcpu->cpu_timer);
 588
 589                         /*
 590                          * Reset idle exit time since we may cancel the timer
 591                          * before it can run after the last idle exit time,
 592                          * to avoid tripping the check in idle exit for a timer
 593                          * that is trying to run.
 594                          */
 595                         pcpu->idle_exit_time = 0;
 596                 }
 597
 598                 flush_work(&freq_scale_down_work);
 599                 if (atomic_dec_return(&active_count) > 0)
 600                         return 0;
 601
 602                 sysfs_remove_group(cpufreq_global_kobject,
 603                                 &interactive_attr_group);
 604
 605                 break;
 606
 607         case CPUFREQ_GOV_LIMITS:
 608                 if (policy->max < policy->cur)
 609                         __cpufreq_driver_target(policy,
 610                                         policy->max, CPUFREQ_RELATION_H);
 611                 else if (policy->min > policy->cur)
 612                         __cpufreq_driver_target(policy,
 613                                         policy->min, CPUFREQ_RELATION_L);
 614                 break;
 615         }
 616         return 0;
 617 }
 618
 619 static int cpufreq_interactive_idle_notifier(struct notifier_block *nb,
 620                                              unsigned long val,
 621                                              void *data)
 622 {
 623         switch (val) {
 624         case IDLE_START:
 625                 cpufreq_interactive_idle_start();
 626                 break;
 627         case IDLE_END:
 628                 cpufreq_interactive_idle_end();
 629                 break;
 630         }
 631
 632         return 0;
 633 }
 634
 635 static struct notifier_block cpufreq_interactive_idle_nb = {
 636         .notifier_call = cpufreq_interactive_idle_notifier,
 637 };
 638
 639 static int __init cpufreq_interactive_init(void)
 640 {
 641         unsigned int i;
 642         struct cpufreq_interactive_cpuinfo *pcpu;
 643         struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
 644
 645         go_hispeed_load = DEFAULT_GO_HISPEED_LOAD;
 646         min_sample_time = DEFAULT_MIN_SAMPLE_TIME;
 647         timer_rate = DEFAULT_TIMER_RATE;
 648
 649         /* Initalize per-cpu timers */
 650         for_each_possible_cpu(i) {
 651                 pcpu = &per_cpu(cpuinfo, i);
 652                 init_timer(&pcpu->cpu_timer);
 653                 pcpu->cpu_timer.function = cpufreq_interactive_timer;
 654                 pcpu->cpu_timer.data = i;
 655         }
 656
 657         up_task = kthread_create(cpufreq_interactive_up_task, NULL,
 658                                  "kinteractiveup");
 659         if (IS_ERR(up_task))
 660                 return PTR_ERR(up_task);
 661
 662         sched_setscheduler_nocheck(up_task, SCHED_FIFO, &param);
 663         get_task_struct(up_task);
 664
 665         /* No rescuer thread, bind to CPU queuing the work for possibly
 666            warm cache (probably doesn't matter much). */
 667         down_wq = alloc_workqueue("knteractive_down", 0, 1);
 668
 669         if (!down_wq)
 670                 goto err_freeuptask;
 671
 672         INIT_WORK(&freq_scale_down_work,
 673                   cpufreq_interactive_freq_down);
 674
 675         spin_lock_init(&up_cpumask_lock);
 676         spin_lock_init(&down_cpumask_lock);
 677         mutex_init(&set_speed_lock);
 678
 679         idle_notifier_register(&cpufreq_interactive_idle_nb);
 680
 681         return cpufreq_register_governor(&cpufreq_gov_interactive);
 682
 683 err_freeuptask:
 684         put_task_struct(up_task);
 685         return -ENOMEM;
 686 }
 687
 688 #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_INTERACTIVE
 689 fs_initcall(cpufreq_interactive_init);
 690 #else
 691 module_init(cpufreq_interactive_init);
 692 #endif
 693
 694 static void __exit cpufreq_interactive_exit(void)
 695 {
 696         cpufreq_unregister_governor(&cpufreq_gov_interactive);
 697         kthread_stop(up_task);
 698         put_task_struct(up_task);
 699         destroy_workqueue(down_wq);
 700 }
 701
 702 module_exit(cpufreq_interactive_exit);
 703
 704 MODULE_AUTHOR("Mike Chan <mike@android.com>");
 705 MODULE_DESCRIPTION("'cpufreq_interactive' - A cpufreq governor for "
 706         "Latency sensitive workloads");
 707 MODULE_LICENSE("GPL");