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/module.h>
  23 #include <linux/moduleparam.h>
  24 #include <linux/mutex.h>
  25 #include <linux/sched.h>
  26 #include <linux/sched/rt.h>
  27 #include <linux/tick.h>
  28 #include <linux/time.h>
  29 #include <linux/timer.h>
  30 #include <linux/workqueue.h>
  31 #include <linux/kthread.h>
  32 #include <linux/mutex.h>
  33 #include <linux/slab.h>
  34 #include <asm/cputime.h>
  35
  36 #define CREATE_TRACE_POINTS
  37 #include <trace/events/cpufreq_interactive.h>
  38
  39 static atomic_t active_count = ATOMIC_INIT(0);
  40
  41 struct cpufreq_interactive_cpuinfo {
  42         struct timer_list cpu_timer;
  43         int timer_idlecancel;
  44         u64 time_in_idle;
  45         u64 idle_exit_time;
  46         u64 target_set_time;
  47         u64 target_set_time_in_idle;
  48         struct cpufreq_policy *policy;
  49         struct cpufreq_frequency_table *freq_table;
  50         unsigned int target_freq;
  51         unsigned int floor_freq;
  52         u64 floor_validate_time;
  53         u64 hispeed_validate_time;
  54         int governor_enabled;
  55 };
  56
  57 static DEFINE_PER_CPU(struct cpufreq_interactive_cpuinfo, cpuinfo);
  58
  59 /* realtime thread handles frequency scaling */
  60 static struct task_struct *speedchange_task;
  61 static cpumask_t speedchange_cpumask;
  62 static spinlock_t speedchange_cpumask_lock;
  63
  64 /* Hi speed to bump to from lo speed when load burst (default max) */
  65 static unsigned int hispeed_freq;
  66
  67 /* Go to hi speed when CPU load at or above this value. */
  68 #define DEFAULT_GO_HISPEED_LOAD 85
  69 static unsigned long go_hispeed_load;
  70
  71 /*
  72  * The minimum amount of time to spend at a frequency before we can ramp down.
  73  */
  74 #define DEFAULT_MIN_SAMPLE_TIME (80 * USEC_PER_MSEC)
  75 static unsigned long min_sample_time;
  76
  77 /*
  78  * The sample rate of the timer used to increase frequency
  79  */
  80 #define DEFAULT_TIMER_RATE (20 * USEC_PER_MSEC)
  81 static unsigned long timer_rate;
  82
  83 /*
  84  * Wait this long before raising speed above hispeed, by default a single
  85  * timer interval.
  86  */
  87 #define DEFAULT_ABOVE_HISPEED_DELAY DEFAULT_TIMER_RATE
  88 static unsigned long above_hispeed_delay_val;
  89
  90 /*
  91  * Non-zero means longer-term speed boost active.
  92  */
  93
  94 static int boost_val;
  95
  96 static bool governidle;
  97 module_param(governidle, bool, S_IWUSR | S_IRUGO);
  98 MODULE_PARM_DESC(governidle,
  99         "Set to 1 to wake up CPUs from idle to reduce speed (default 0)");
 100
 101 static int cpufreq_governor_interactive(struct cpufreq_policy *policy,
 102                 unsigned int event);
 103
 104 #ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_INTERACTIVE
 105 static
 106 #endif
 107 struct cpufreq_governor cpufreq_gov_interactive = {
 108         .name = "interactive",
 109         .governor = cpufreq_governor_interactive,
 110         .max_transition_latency = 10000000,
 111         .owner = THIS_MODULE,
 112 };
 113
 114 static void cpufreq_interactive_timer(unsigned long data)
 115 {
 116         u64 now;
 117         unsigned int delta_idle;
 118         unsigned int delta_time;
 119         int cpu_load;
 120         int load_since_change;
 121         u64 time_in_idle;
 122         u64 idle_exit_time;
 123         struct cpufreq_interactive_cpuinfo *pcpu =
 124                 &per_cpu(cpuinfo, data);
 125         u64 now_idle;
 126         unsigned int new_freq;
 127         unsigned int index;
 128         unsigned long flags;
 129
 130         smp_rmb();
 131
 132         if (!pcpu->governor_enabled)
 133                 goto exit;
 134
 135         time_in_idle = pcpu->time_in_idle;
 136         idle_exit_time = pcpu->idle_exit_time;
 137         now_idle = get_cpu_idle_time_us(data, &now);
 138         delta_idle = (unsigned int)(now_idle - time_in_idle);
 139         delta_time = (unsigned int)(now - idle_exit_time);
 140
 141         /*
 142          * If timer ran less than 1ms after short-term sample started, retry.
 143          */
 144         if (delta_time < 1000)
 145                 goto rearm;
 146
 147         if (delta_idle > delta_time)
 148                 cpu_load = 0;
 149         else
 150                 cpu_load = 100 * (delta_time - delta_idle) / delta_time;
 151
 152         delta_idle = (unsigned int)(now_idle - pcpu->target_set_time_in_idle);
 153         delta_time = (unsigned int)(now - pcpu->target_set_time);
 154
 155         if ((delta_time == 0) || (delta_idle > delta_time))
 156                 load_since_change = 0;
 157         else
 158                 load_since_change =
 159                         100 * (delta_time - delta_idle) / delta_time;
 160
 161         /*
 162          * Choose greater of short-term load (since last idle timer
 163          * started or timer function re-armed itself) or long-term load
 164          * (since last frequency change).
 165          */
 166         if (load_since_change > cpu_load)
 167                 cpu_load = load_since_change;
 168
 169         if (cpu_load >= go_hispeed_load || boost_val) {
 170                 if (pcpu->target_freq < hispeed_freq &&
 171                     hispeed_freq < pcpu->policy->max) {
 172                         new_freq = hispeed_freq;
 173                 } else {
 174                         new_freq = pcpu->policy->max * cpu_load / 100;
 175
 176                         if (new_freq < hispeed_freq)
 177                                 new_freq = hispeed_freq;
 178
 179                         if (pcpu->target_freq == hispeed_freq &&
 180                             new_freq > hispeed_freq &&
 181                             now - pcpu->hispeed_validate_time
 182                             < above_hispeed_delay_val) {
 183                                 trace_cpufreq_interactive_notyet(data, cpu_load,
 184                                                                  pcpu->target_freq,
 185                                                                  new_freq);
 186                                 goto rearm;
 187                         }
 188                 }
 189         } else {
 190                 new_freq = hispeed_freq * cpu_load / 100;
 191         }
 192
 193         if (new_freq <= hispeed_freq)
 194                 pcpu->hispeed_validate_time = now;
 195
 196         if (cpufreq_frequency_table_target(pcpu->policy, pcpu->freq_table,
 197                                            new_freq, CPUFREQ_RELATION_H,
 198                                            &index)) {
 199                 pr_warn_once("timer %d: cpufreq_frequency_table_target error\n",
 200                              (int) data);
 201                 goto rearm;
 202         }
 203
 204         new_freq = pcpu->freq_table[index].frequency;
 205
 206         /*
 207          * Do not scale below floor_freq unless we have been at or above the
 208          * floor frequency for the minimum sample time since last validated.
 209          */
 210         if (new_freq < pcpu->floor_freq) {
 211                 if (now - pcpu->floor_validate_time < min_sample_time) {
 212                         trace_cpufreq_interactive_notyet(data, cpu_load,
 213                                          pcpu->target_freq, new_freq);
 214                         goto rearm;
 215                 }
 216         }
 217
 218         pcpu->floor_freq = new_freq;
 219         pcpu->floor_validate_time = now;
 220
 221         if (pcpu->target_freq == new_freq) {
 222                 trace_cpufreq_interactive_already(data, cpu_load,
 223                                                   pcpu->target_freq, new_freq);
 224                 goto rearm_if_notmax;
 225         }
 226
 227         trace_cpufreq_interactive_target(data, cpu_load, pcpu->target_freq,
 228                                          new_freq);
 229         pcpu->target_set_time_in_idle = now_idle;
 230         pcpu->target_set_time = now;
 231
 232         pcpu->target_freq = new_freq;
 233         spin_lock_irqsave(&speedchange_cpumask_lock, flags);
 234         cpumask_set_cpu(data, &speedchange_cpumask);
 235         spin_unlock_irqrestore(&speedchange_cpumask_lock, flags);
 236         wake_up_process(speedchange_task);
 237
 238 rearm_if_notmax:
 239         /*
 240          * Already set max speed and don't see a need to change that,
 241          * wait until next idle to re-evaluate, don't need timer.
 242          */
 243         if (pcpu->target_freq == pcpu->policy->max)
 244                 goto exit;
 245
 246 rearm:
 247         if (!timer_pending(&pcpu->cpu_timer)) {
 248                 /*
 249                  * If governing speed in idle and already at min, cancel the
 250                  * timer if that CPU goes idle.  We don't need to re-evaluate
 251                  * speed until the next idle exit.
 252                  */
 253                 if (governidle && pcpu->target_freq == pcpu->policy->min)
 254                         pcpu->timer_idlecancel = 1;
 255
 256                 pcpu->time_in_idle = get_cpu_idle_time_us(
 257                         data, &pcpu->idle_exit_time);
 258                 mod_timer_pinned(&pcpu->cpu_timer,
 259                                  jiffies + usecs_to_jiffies(timer_rate));
 260         }
 261
 262 exit:
 263         return;
 264 }
 265
 266 static void cpufreq_interactive_idle_start(void)
 267 {
 268         struct cpufreq_interactive_cpuinfo *pcpu =
 269                 &per_cpu(cpuinfo, smp_processor_id());
 270         int pending;
 271
 272         if (!pcpu->governor_enabled)
 273                 return;
 274
 275         pending = timer_pending(&pcpu->cpu_timer);
 276
 277         if (pcpu->target_freq != pcpu->policy->min) {
 278                 /*
 279                  * Entering idle while not at lowest speed.  On some
 280                  * platforms this can hold the other CPU(s) at that speed
 281                  * even though the CPU is idle. Set a timer to re-evaluate
 282                  * speed so this idle CPU doesn't hold the other CPUs above
 283                  * min indefinitely.  This should probably be a quirk of
 284                  * the CPUFreq driver.
 285                  */
 286                 if (!pending) {
 287                         pcpu->time_in_idle = get_cpu_idle_time_us(
 288                                 smp_processor_id(), &pcpu->idle_exit_time);
 289                         pcpu->timer_idlecancel = 0;
 290                         mod_timer_pinned(
 291                                 &pcpu->cpu_timer,
 292                                 jiffies + usecs_to_jiffies(timer_rate));
 293                 }
 294         } else if (governidle) {
 295                 /*
 296                  * If at min speed and entering idle after load has
 297                  * already been evaluated, and a timer has been set just in
 298                  * case the CPU suddenly goes busy, cancel that timer.  The
 299                  * CPU didn't go busy; we'll recheck things upon idle exit.
 300                  */
 301                 if (pending && pcpu->timer_idlecancel) {
 302                         del_timer(&pcpu->cpu_timer);
 303                         pcpu->timer_idlecancel = 0;
 304                 }
 305         }
 306
 307 }
 308
 309 static void cpufreq_interactive_idle_end(void)
 310 {
 311         struct cpufreq_interactive_cpuinfo *pcpu =
 312                 &per_cpu(cpuinfo, smp_processor_id());
 313
 314         if (!pcpu->governor_enabled)
 315                 return;
 316
 317         /* Arm the timer for 1-2 ticks later if not already. */
 318         if (!timer_pending(&pcpu->cpu_timer)) {
 319                 pcpu->time_in_idle =
 320                         get_cpu_idle_time_us(smp_processor_id(),
 321                                              &pcpu->idle_exit_time);
 322                 pcpu->timer_idlecancel = 0;
 323                 mod_timer_pinned(
 324                         &pcpu->cpu_timer,
 325                         jiffies + usecs_to_jiffies(timer_rate));
 326         }
 327
 328 }
 329
 330 static int cpufreq_interactive_speedchange_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(&speedchange_cpumask_lock, flags);
 340
 341                 if (cpumask_empty(&speedchange_cpumask)) {
 342                         spin_unlock_irqrestore(&speedchange_cpumask_lock,
 343                                                flags);
 344                         schedule();
 345
 346                         if (kthread_should_stop())
 347                                 break;
 348
 349                         spin_lock_irqsave(&speedchange_cpumask_lock, flags);
 350                 }
 351
 352                 set_current_state(TASK_RUNNING);
 353                 tmp_mask = speedchange_cpumask;
 354                 cpumask_clear(&speedchange_cpumask);
 355                 spin_unlock_irqrestore(&speedchange_cpumask_lock, flags);
 356
 357                 for_each_cpu(cpu, &tmp_mask) {
 358                         unsigned int j;
 359                         unsigned int max_freq = 0;
 360
 361                         pcpu = &per_cpu(cpuinfo, cpu);
 362                         smp_rmb();
 363
 364                         if (!pcpu->governor_enabled)
 365                                 continue;
 366
 367                         for_each_cpu(j, pcpu->policy->cpus) {
 368                                 struct cpufreq_interactive_cpuinfo *pjcpu =
 369                                         &per_cpu(cpuinfo, j);
 370
 371                                 if (pjcpu->target_freq > max_freq)
 372                                         max_freq = pjcpu->target_freq;
 373                         }
 374
 375                         if (max_freq != pcpu->policy->cur)
 376                                 __cpufreq_driver_target(pcpu->policy,
 377                                                         max_freq,
 378                                                         CPUFREQ_RELATION_H);
 379                         trace_cpufreq_interactive_setspeed(cpu,
 380                                                      pcpu->target_freq,
 381                                                      pcpu->policy->cur);
 382                 }
 383         }
 384
 385         return 0;
 386 }
 387
 388 static void cpufreq_interactive_boost(void)
 389 {
 390         int i;
 391         int anyboost = 0;
 392         unsigned long flags;
 393         struct cpufreq_interactive_cpuinfo *pcpu;
 394
 395         spin_lock_irqsave(&speedchange_cpumask_lock, flags);
 396
 397         for_each_online_cpu(i) {
 398                 pcpu = &per_cpu(cpuinfo, i);
 399
 400                 if (pcpu->target_freq < hispeed_freq) {
 401                         pcpu->target_freq = hispeed_freq;
 402                         cpumask_set_cpu(i, &speedchange_cpumask);
 403                         pcpu->target_set_time_in_idle =
 404                                 get_cpu_idle_time_us(i, &pcpu->target_set_time);
 405                         pcpu->hispeed_validate_time = pcpu->target_set_time;
 406                         anyboost = 1;
 407                 }
 408
 409                 /*
 410                  * Set floor freq and (re)start timer for when last
 411                  * validated.
 412                  */
 413
 414                 pcpu->floor_freq = hispeed_freq;
 415                 pcpu->floor_validate_time = ktime_to_us(ktime_get());
 416         }
 417
 418         spin_unlock_irqrestore(&speedchange_cpumask_lock, flags);
 419
 420         if (anyboost)
 421                 wake_up_process(speedchange_task);
 422 }
 423
 424 static ssize_t show_hispeed_freq(struct kobject *kobj,
 425                                  struct attribute *attr, char *buf)
 426 {
 427         return sprintf(buf, "%u\n", hispeed_freq);
 428 }
 429
 430 static ssize_t store_hispeed_freq(struct kobject *kobj,
 431                                   struct attribute *attr, const char *buf,
 432                                   size_t count)
 433 {
 434         int ret;
 435         long unsigned int val;
 436
 437         ret = strict_strtoul(buf, 0, &val);
 438         if (ret < 0)
 439                 return ret;
 440         hispeed_freq = val;
 441         return count;
 442 }
 443
 444 static struct global_attr hispeed_freq_attr = __ATTR(hispeed_freq, 0644,
 445                 show_hispeed_freq, store_hispeed_freq);
 446
 447
 448 static ssize_t show_go_hispeed_load(struct kobject *kobj,
 449                                      struct attribute *attr, char *buf)
 450 {
 451         return sprintf(buf, "%lu\n", go_hispeed_load);
 452 }
 453
 454 static ssize_t store_go_hispeed_load(struct kobject *kobj,
 455                         struct attribute *attr, const char *buf, size_t count)
 456 {
 457         int ret;
 458         unsigned long val;
 459
 460         ret = strict_strtoul(buf, 0, &val);
 461         if (ret < 0)
 462                 return ret;
 463         go_hispeed_load = val;
 464         return count;
 465 }
 466
 467 static struct global_attr go_hispeed_load_attr = __ATTR(go_hispeed_load, 0644,
 468                 show_go_hispeed_load, store_go_hispeed_load);
 469
 470 static ssize_t show_min_sample_time(struct kobject *kobj,
 471                                 struct attribute *attr, char *buf)
 472 {
 473         return sprintf(buf, "%lu\n", min_sample_time);
 474 }
 475
 476 static ssize_t store_min_sample_time(struct kobject *kobj,
 477                         struct attribute *attr, const char *buf, size_t count)
 478 {
 479         int ret;
 480         unsigned long val;
 481
 482         ret = strict_strtoul(buf, 0, &val);
 483         if (ret < 0)
 484                 return ret;
 485         min_sample_time = val;
 486         return count;
 487 }
 488
 489 static struct global_attr min_sample_time_attr = __ATTR(min_sample_time, 0644,
 490                 show_min_sample_time, store_min_sample_time);
 491
 492 static ssize_t show_above_hispeed_delay(struct kobject *kobj,
 493                                         struct attribute *attr, char *buf)
 494 {
 495         return sprintf(buf, "%lu\n", above_hispeed_delay_val);
 496 }
 497
 498 static ssize_t store_above_hispeed_delay(struct kobject *kobj,
 499                                          struct attribute *attr,
 500                                          const char *buf, size_t count)
 501 {
 502         int ret;
 503         unsigned long val;
 504
 505         ret = strict_strtoul(buf, 0, &val);
 506         if (ret < 0)
 507                 return ret;
 508         above_hispeed_delay_val = val;
 509         return count;
 510 }
 511
 512 define_one_global_rw(above_hispeed_delay);
 513
 514 static ssize_t show_timer_rate(struct kobject *kobj,
 515                         struct attribute *attr, char *buf)
 516 {
 517         return sprintf(buf, "%lu\n", timer_rate);
 518 }
 519
 520 static ssize_t store_timer_rate(struct kobject *kobj,
 521                         struct attribute *attr, const char *buf, size_t count)
 522 {
 523         int ret;
 524         unsigned long val;
 525
 526         ret = strict_strtoul(buf, 0, &val);
 527         if (ret < 0)
 528                 return ret;
 529         timer_rate = val;
 530         return count;
 531 }
 532
 533 static struct global_attr timer_rate_attr = __ATTR(timer_rate, 0644,
 534                 show_timer_rate, store_timer_rate);
 535
 536 static ssize_t show_boost(struct kobject *kobj, struct attribute *attr,
 537                           char *buf)
 538 {
 539         return sprintf(buf, "%d\n", boost_val);
 540 }
 541
 542 static ssize_t store_boost(struct kobject *kobj, struct attribute *attr,
 543                            const char *buf, size_t count)
 544 {
 545         int ret;
 546         unsigned long val;
 547
 548         ret = kstrtoul(buf, 0, &val);
 549         if (ret < 0)
 550                 return ret;
 551
 552         boost_val = val;
 553
 554         if (boost_val) {
 555                 trace_cpufreq_interactive_boost("on");
 556                 cpufreq_interactive_boost();
 557         } else {
 558                 trace_cpufreq_interactive_unboost("off");
 559         }
 560
 561         return count;
 562 }
 563
 564 define_one_global_rw(boost);
 565
 566 static ssize_t store_boostpulse(struct kobject *kobj, struct attribute *attr,
 567                                 const char *buf, size_t count)
 568 {
 569         int ret;
 570         unsigned long val;
 571
 572         ret = kstrtoul(buf, 0, &val);
 573         if (ret < 0)
 574                 return ret;
 575
 576         trace_cpufreq_interactive_boost("pulse");
 577         cpufreq_interactive_boost();
 578         return count;
 579 }
 580
 581 static struct global_attr boostpulse =
 582         __ATTR(boostpulse, 0200, NULL, store_boostpulse);
 583
 584 static struct attribute *interactive_attributes[] = {
 585         &hispeed_freq_attr.attr,
 586         &go_hispeed_load_attr.attr,
 587         &above_hispeed_delay.attr,
 588         &min_sample_time_attr.attr,
 589         &timer_rate_attr.attr,
 590         &boost.attr,
 591         &boostpulse.attr,
 592         NULL,
 593 };
 594
 595 static struct attribute_group interactive_attr_group = {
 596         .attrs = interactive_attributes,
 597         .name = "interactive",
 598 };
 599
 600 static int cpufreq_interactive_idle_notifier(struct notifier_block *nb,
 601                                              unsigned long val,
 602                                              void *data)
 603 {
 604         switch (val) {
 605         case IDLE_START:
 606                 cpufreq_interactive_idle_start();
 607                 break;
 608         case IDLE_END:
 609                 cpufreq_interactive_idle_end();
 610                 break;
 611         }
 612
 613         return 0;
 614 }
 615
 616 static struct notifier_block cpufreq_interactive_idle_nb = {
 617         .notifier_call = cpufreq_interactive_idle_notifier,
 618 };
 619
 620 static int cpufreq_governor_interactive(struct cpufreq_policy *policy,
 621                 unsigned int event)
 622 {
 623         int rc;
 624         unsigned int j;
 625         struct cpufreq_interactive_cpuinfo *pcpu;
 626         struct cpufreq_frequency_table *freq_table;
 627
 628         switch (event) {
 629         case CPUFREQ_GOV_START:
 630                 if (!cpu_online(policy->cpu))
 631                         return -EINVAL;
 632
 633                 freq_table =
 634                         cpufreq_frequency_get_table(policy->cpu);
 635                 if (!hispeed_freq)
 636                         hispeed_freq = policy->max;
 637
 638                 for_each_cpu(j, policy->cpus) {
 639                         pcpu = &per_cpu(cpuinfo, j);
 640                         pcpu->policy = policy;
 641                         pcpu->target_freq = policy->cur;
 642                         pcpu->freq_table = freq_table;
 643                         pcpu->target_set_time_in_idle =
 644                                 get_cpu_idle_time_us(j,
 645                                              &pcpu->target_set_time);
 646                         pcpu->floor_freq = pcpu->target_freq;
 647                         pcpu->floor_validate_time =
 648                                 pcpu->target_set_time;
 649                         pcpu->hispeed_validate_time =
 650                                 pcpu->target_set_time;
 651                         pcpu->governor_enabled = 1;
 652                         smp_wmb();
 653                         pcpu->cpu_timer.expires =
 654                                 jiffies + usecs_to_jiffies(timer_rate);
 655                         add_timer_on(&pcpu->cpu_timer, j);
 656                 }
 657
 658                 /*
 659                  * Do not register the idle hook and create sysfs
 660                  * entries if we have already done so.
 661                  */
 662                 if (atomic_inc_return(&active_count) > 1)
 663                         return 0;
 664
 665                 rc = sysfs_create_group(cpufreq_global_kobject,
 666                                 &interactive_attr_group);
 667                 if (rc)
 668                         return rc;
 669
 670                 idle_notifier_register(&cpufreq_interactive_idle_nb);
 671                 break;
 672
 673         case CPUFREQ_GOV_STOP:
 674                 for_each_cpu(j, policy->cpus) {
 675                         pcpu = &per_cpu(cpuinfo, j);
 676                         pcpu->governor_enabled = 0;
 677                         smp_wmb();
 678                         del_timer_sync(&pcpu->cpu_timer);
 679                 }
 680
 681                 if (atomic_dec_return(&active_count) > 0)
 682                         return 0;
 683
 684                 idle_notifier_unregister(&cpufreq_interactive_idle_nb);
 685                 sysfs_remove_group(cpufreq_global_kobject,
 686                                 &interactive_attr_group);
 687
 688                 break;
 689
 690         case CPUFREQ_GOV_LIMITS:
 691                 if (policy->max < policy->cur)
 692                         __cpufreq_driver_target(policy,
 693                                         policy->max, CPUFREQ_RELATION_H);
 694                 else if (policy->min > policy->cur)
 695                         __cpufreq_driver_target(policy,
 696                                         policy->min, CPUFREQ_RELATION_L);
 697                 break;
 698         }
 699         return 0;
 700 }
 701
 702 static int __init cpufreq_interactive_init(void)
 703 {
 704         unsigned int i;
 705         struct cpufreq_interactive_cpuinfo *pcpu;
 706         struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
 707
 708         go_hispeed_load = DEFAULT_GO_HISPEED_LOAD;
 709         min_sample_time = DEFAULT_MIN_SAMPLE_TIME;
 710         above_hispeed_delay_val = DEFAULT_ABOVE_HISPEED_DELAY;
 711         timer_rate = DEFAULT_TIMER_RATE;
 712
 713         /* Initalize per-cpu timers */
 714         for_each_possible_cpu(i) {
 715                 pcpu = &per_cpu(cpuinfo, i);
 716                 if (governidle)
 717                         init_timer(&pcpu->cpu_timer);
 718                 else
 719                         init_timer_deferrable(&pcpu->cpu_timer);
 720                 pcpu->cpu_timer.function = cpufreq_interactive_timer;
 721                 pcpu->cpu_timer.data = i;
 722         }
 723
 724         spin_lock_init(&speedchange_cpumask_lock);
 725         speedchange_task =
 726                 kthread_create(cpufreq_interactive_speedchange_task, NULL,
 727                                "cfinteractive");
 728         if (IS_ERR(speedchange_task))
 729                 return PTR_ERR(speedchange_task);
 730
 731         sched_setscheduler_nocheck(speedchange_task, SCHED_FIFO, &param);
 732         get_task_struct(speedchange_task);
 733
 734         /* NB: wake up so the thread does not look hung to the freezer */
 735         wake_up_process(speedchange_task);
 736
 737         return cpufreq_register_governor(&cpufreq_gov_interactive);
 738 }
 739
 740 #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_INTERACTIVE
 741 fs_initcall(cpufreq_interactive_init);
 742 #else
 743 module_init(cpufreq_interactive_init);
 744 #endif
 745
 746 static void __exit cpufreq_interactive_exit(void)
 747 {
 748         cpufreq_unregister_governor(&cpufreq_gov_interactive);
 749         kthread_stop(speedchange_task);
 750         put_task_struct(speedchange_task);
 751 }
 752
 753 module_exit(cpufreq_interactive_exit);
 754
 755 MODULE_AUTHOR("Mike Chan <mike@android.com>");
 756 MODULE_DESCRIPTION("'cpufreq_interactive' - A cpufreq governor for "
 757         "Latency sensitive workloads");
 758 MODULE_LICENSE("GPL");