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 time_in_idle_timestamp;
  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_resched(
 115         struct cpufreq_interactive_cpuinfo *pcpu)
 116 {
 117         mod_timer_pinned(&pcpu->cpu_timer,
 118                          jiffies + usecs_to_jiffies(timer_rate));
 119         pcpu->time_in_idle =
 120                 get_cpu_idle_time_us(smp_processor_id(),
 121                                      &pcpu->time_in_idle_timestamp);
 122 }
 123
 124 static void cpufreq_interactive_timer(unsigned long data)
 125 {
 126         u64 now;
 127         unsigned int delta_idle;
 128         unsigned int delta_time;
 129         int cpu_load;
 130         int load_since_change;
 131         struct cpufreq_interactive_cpuinfo *pcpu =
 132                 &per_cpu(cpuinfo, data);
 133         u64 now_idle;
 134         unsigned int new_freq;
 135         unsigned int index;
 136         unsigned long flags;
 137
 138         smp_rmb();
 139
 140         if (!pcpu->governor_enabled)
 141                 goto exit;
 142
 143         now_idle = get_cpu_idle_time_us(data, &now);
 144         delta_idle = (unsigned int)(now_idle - pcpu->time_in_idle);
 145         delta_time = (unsigned int)(now - pcpu->time_in_idle_timestamp);
 146
 147         /*
 148          * If timer ran less than 1ms after short-term sample started, retry.
 149          */
 150         if (delta_time < 1000)
 151                 goto rearm;
 152
 153         if (delta_idle > delta_time)
 154                 cpu_load = 0;
 155         else
 156                 cpu_load = 100 * (delta_time - delta_idle) / delta_time;
 157
 158         delta_idle = (unsigned int)(now_idle - pcpu->target_set_time_in_idle);
 159         delta_time = (unsigned int)(now - pcpu->target_set_time);
 160
 161         if ((delta_time == 0) || (delta_idle > delta_time))
 162                 load_since_change = 0;
 163         else
 164                 load_since_change =
 165                         100 * (delta_time - delta_idle) / delta_time;
 166
 167         /*
 168          * Choose greater of short-term load (since last idle timer
 169          * started or timer function re-armed itself) or long-term load
 170          * (since last frequency change).
 171          */
 172         if (load_since_change > cpu_load)
 173                 cpu_load = load_since_change;
 174
 175         if (cpu_load >= go_hispeed_load || boost_val) {
 176                 if (pcpu->target_freq < hispeed_freq &&
 177                     hispeed_freq < pcpu->policy->max) {
 178                         new_freq = hispeed_freq;
 179                 } else {
 180                         new_freq = pcpu->policy->max * cpu_load / 100;
 181
 182                         if (new_freq < hispeed_freq)
 183                                 new_freq = hispeed_freq;
 184
 185                         if (pcpu->target_freq == hispeed_freq &&
 186                             new_freq > hispeed_freq &&
 187                             now - pcpu->hispeed_validate_time
 188                             < above_hispeed_delay_val) {
 189                                 trace_cpufreq_interactive_notyet(
 190                                         data, cpu_load, pcpu->target_freq,
 191                                         pcpu->policy->cur, new_freq);
 192                                 goto rearm;
 193                         }
 194                 }
 195         } else {
 196                 new_freq = hispeed_freq * cpu_load / 100;
 197         }
 198
 199         if (new_freq <= hispeed_freq)
 200                 pcpu->hispeed_validate_time = now;
 201
 202         if (cpufreq_frequency_table_target(pcpu->policy, pcpu->freq_table,
 203                                            new_freq, CPUFREQ_RELATION_H,
 204                                            &index)) {
 205                 pr_warn_once("timer %d: cpufreq_frequency_table_target error\n",
 206                              (int) data);
 207                 goto rearm;
 208         }
 209
 210         new_freq = pcpu->freq_table[index].frequency;
 211
 212         /*
 213          * Do not scale below floor_freq unless we have been at or above the
 214          * floor frequency for the minimum sample time since last validated.
 215          */
 216         if (new_freq < pcpu->floor_freq) {
 217                 if (now - pcpu->floor_validate_time < min_sample_time) {
 218                         trace_cpufreq_interactive_notyet(
 219                                 data, cpu_load, pcpu->target_freq,
 220                                 pcpu->policy->cur, new_freq);
 221                         goto rearm;
 222                 }
 223         }
 224
 225         pcpu->floor_freq = new_freq;
 226         pcpu->floor_validate_time = now;
 227
 228         if (pcpu->target_freq == new_freq) {
 229                 trace_cpufreq_interactive_already(
 230                         data, cpu_load, pcpu->target_freq,
 231                         pcpu->policy->cur, new_freq);
 232                 goto rearm_if_notmax;
 233         }
 234
 235         trace_cpufreq_interactive_target(data, cpu_load, pcpu->target_freq,
 236                                          pcpu->policy->cur, new_freq);
 237         pcpu->target_set_time_in_idle = now_idle;
 238         pcpu->target_set_time = now;
 239
 240         pcpu->target_freq = new_freq;
 241         spin_lock_irqsave(&speedchange_cpumask_lock, flags);
 242         cpumask_set_cpu(data, &speedchange_cpumask);
 243         spin_unlock_irqrestore(&speedchange_cpumask_lock, flags);
 244         wake_up_process(speedchange_task);
 245
 246 rearm_if_notmax:
 247         /*
 248          * Already set max speed and don't see a need to change that,
 249          * wait until next idle to re-evaluate, don't need timer.
 250          */
 251         if (pcpu->target_freq == pcpu->policy->max)
 252                 goto exit;
 253
 254 rearm:
 255         if (!timer_pending(&pcpu->cpu_timer)) {
 256                 /*
 257                  * If governing speed in idle and already at min, cancel the
 258                  * timer if that CPU goes idle.  We don't need to re-evaluate
 259                  * speed until the next idle exit.
 260                  */
 261                 if (governidle && pcpu->target_freq == pcpu->policy->min)
 262                         pcpu->timer_idlecancel = 1;
 263
 264                 cpufreq_interactive_timer_resched(pcpu);
 265         }
 266
 267 exit:
 268         return;
 269 }
 270
 271 static void cpufreq_interactive_idle_start(void)
 272 {
 273         struct cpufreq_interactive_cpuinfo *pcpu =
 274                 &per_cpu(cpuinfo, smp_processor_id());
 275         int pending;
 276
 277         if (!pcpu->governor_enabled)
 278                 return;
 279
 280         pending = timer_pending(&pcpu->cpu_timer);
 281
 282         if (pcpu->target_freq != pcpu->policy->min) {
 283                 /*
 284                  * Entering idle while not at lowest speed.  On some
 285                  * platforms this can hold the other CPU(s) at that speed
 286                  * even though the CPU is idle. Set a timer to re-evaluate
 287                  * speed so this idle CPU doesn't hold the other CPUs above
 288                  * min indefinitely.  This should probably be a quirk of
 289                  * the CPUFreq driver.
 290                  */
 291                 if (!pending) {
 292                         pcpu->timer_idlecancel = 0;
 293                         cpufreq_interactive_timer_resched(pcpu);
 294                 }
 295         } else if (governidle) {
 296                 /*
 297                  * If at min speed and entering idle after load has
 298                  * already been evaluated, and a timer has been set just in
 299                  * case the CPU suddenly goes busy, cancel that timer.  The
 300                  * CPU didn't go busy; we'll recheck things upon idle exit.
 301                  */
 302                 if (pending && pcpu->timer_idlecancel) {
 303                         del_timer(&pcpu->cpu_timer);
 304                         pcpu->timer_idlecancel = 0;
 305                 }
 306         }
 307
 308 }
 309
 310 static void cpufreq_interactive_idle_end(void)
 311 {
 312         struct cpufreq_interactive_cpuinfo *pcpu =
 313                 &per_cpu(cpuinfo, smp_processor_id());
 314
 315         if (!pcpu->governor_enabled)
 316                 return;
 317
 318         /* Arm the timer for 1-2 ticks later if not already. */
 319         if (!timer_pending(&pcpu->cpu_timer)) {
 320                 pcpu->timer_idlecancel = 0;
 321                 cpufreq_interactive_timer_resched(pcpu);
 322         } else if (!governidle &&
 323                    time_after_eq(jiffies, pcpu->cpu_timer.expires)) {
 324                 del_timer(&pcpu->cpu_timer);
 325                 cpufreq_interactive_timer(smp_processor_id());
 326         }
 327 }
 328
 329 static int cpufreq_interactive_speedchange_task(void *data)
 330 {
 331         unsigned int cpu;
 332         cpumask_t tmp_mask;
 333         unsigned long flags;
 334         struct cpufreq_interactive_cpuinfo *pcpu;
 335
 336         while (1) {
 337                 set_current_state(TASK_INTERRUPTIBLE);
 338                 spin_lock_irqsave(&speedchange_cpumask_lock, flags);
 339
 340                 if (cpumask_empty(&speedchange_cpumask)) {
 341                         spin_unlock_irqrestore(&speedchange_cpumask_lock,
 342                                                flags);
 343                         schedule();
 344
 345                         if (kthread_should_stop())
 346                                 break;
 347
 348                         spin_lock_irqsave(&speedchange_cpumask_lock, flags);
 349                 }
 350
 351                 set_current_state(TASK_RUNNING);
 352                 tmp_mask = speedchange_cpumask;
 353                 cpumask_clear(&speedchange_cpumask);
 354                 spin_unlock_irqrestore(&speedchange_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                         for_each_cpu(j, pcpu->policy->cpus) {
 367                                 struct cpufreq_interactive_cpuinfo *pjcpu =
 368                                         &per_cpu(cpuinfo, j);
 369
 370                                 if (pjcpu->target_freq > max_freq)
 371                                         max_freq = pjcpu->target_freq;
 372                         }
 373
 374                         if (max_freq != pcpu->policy->cur)
 375                                 __cpufreq_driver_target(pcpu->policy,
 376                                                         max_freq,
 377                                                         CPUFREQ_RELATION_H);
 378                         trace_cpufreq_interactive_setspeed(cpu,
 379                                                      pcpu->target_freq,
 380                                                      pcpu->policy->cur);
 381                 }
 382         }
 383
 384         return 0;
 385 }
 386
 387 static void cpufreq_interactive_boost(void)
 388 {
 389         int i;
 390         int anyboost = 0;
 391         unsigned long flags;
 392         struct cpufreq_interactive_cpuinfo *pcpu;
 393
 394         spin_lock_irqsave(&speedchange_cpumask_lock, flags);
 395
 396         for_each_online_cpu(i) {
 397                 pcpu = &per_cpu(cpuinfo, i);
 398
 399                 if (pcpu->target_freq < hispeed_freq) {
 400                         pcpu->target_freq = hispeed_freq;
 401                         cpumask_set_cpu(i, &speedchange_cpumask);
 402                         pcpu->target_set_time_in_idle =
 403                                 get_cpu_idle_time_us(i, &pcpu->target_set_time);
 404                         pcpu->hispeed_validate_time = pcpu->target_set_time;
 405                         anyboost = 1;
 406                 }
 407
 408                 /*
 409                  * Set floor freq and (re)start timer for when last
 410                  * validated.
 411                  */
 412
 413                 pcpu->floor_freq = hispeed_freq;
 414                 pcpu->floor_validate_time = ktime_to_us(ktime_get());
 415         }
 416
 417         spin_unlock_irqrestore(&speedchange_cpumask_lock, flags);
 418
 419         if (anyboost)
 420                 wake_up_process(speedchange_task);
 421 }
 422
 423 static ssize_t show_hispeed_freq(struct kobject *kobj,
 424                                  struct attribute *attr, char *buf)
 425 {
 426         return sprintf(buf, "%u\n", hispeed_freq);
 427 }
 428
 429 static ssize_t store_hispeed_freq(struct kobject *kobj,
 430                                   struct attribute *attr, const char *buf,
 431                                   size_t count)
 432 {
 433         int ret;
 434         long unsigned int val;
 435
 436         ret = strict_strtoul(buf, 0, &val);
 437         if (ret < 0)
 438                 return ret;
 439         hispeed_freq = val;
 440         return count;
 441 }
 442
 443 static struct global_attr hispeed_freq_attr = __ATTR(hispeed_freq, 0644,
 444                 show_hispeed_freq, store_hispeed_freq);
 445
 446
 447 static ssize_t show_go_hispeed_load(struct kobject *kobj,
 448                                      struct attribute *attr, char *buf)
 449 {
 450         return sprintf(buf, "%lu\n", go_hispeed_load);
 451 }
 452
 453 static ssize_t store_go_hispeed_load(struct kobject *kobj,
 454                         struct attribute *attr, const char *buf, size_t count)
 455 {
 456         int ret;
 457         unsigned long val;
 458
 459         ret = strict_strtoul(buf, 0, &val);
 460         if (ret < 0)
 461                 return ret;
 462         go_hispeed_load = val;
 463         return count;
 464 }
 465
 466 static struct global_attr go_hispeed_load_attr = __ATTR(go_hispeed_load, 0644,
 467                 show_go_hispeed_load, store_go_hispeed_load);
 468
 469 static ssize_t show_min_sample_time(struct kobject *kobj,
 470                                 struct attribute *attr, char *buf)
 471 {
 472         return sprintf(buf, "%lu\n", min_sample_time);
 473 }
 474
 475 static ssize_t store_min_sample_time(struct kobject *kobj,
 476                         struct attribute *attr, const char *buf, size_t count)
 477 {
 478         int ret;
 479         unsigned long val;
 480
 481         ret = strict_strtoul(buf, 0, &val);
 482         if (ret < 0)
 483                 return ret;
 484         min_sample_time = val;
 485         return count;
 486 }
 487
 488 static struct global_attr min_sample_time_attr = __ATTR(min_sample_time, 0644,
 489                 show_min_sample_time, store_min_sample_time);
 490
 491 static ssize_t show_above_hispeed_delay(struct kobject *kobj,
 492                                         struct attribute *attr, char *buf)
 493 {
 494         return sprintf(buf, "%lu\n", above_hispeed_delay_val);
 495 }
 496
 497 static ssize_t store_above_hispeed_delay(struct kobject *kobj,
 498                                          struct attribute *attr,
 499                                          const char *buf, size_t count)
 500 {
 501         int ret;
 502         unsigned long val;
 503
 504         ret = strict_strtoul(buf, 0, &val);
 505         if (ret < 0)
 506                 return ret;
 507         above_hispeed_delay_val = val;
 508         return count;
 509 }
 510
 511 define_one_global_rw(above_hispeed_delay);
 512
 513 static ssize_t show_timer_rate(struct kobject *kobj,
 514                         struct attribute *attr, char *buf)
 515 {
 516         return sprintf(buf, "%lu\n", timer_rate);
 517 }
 518
 519 static ssize_t store_timer_rate(struct kobject *kobj,
 520                         struct attribute *attr, const char *buf, size_t count)
 521 {
 522         int ret;
 523         unsigned long val;
 524
 525         ret = strict_strtoul(buf, 0, &val);
 526         if (ret < 0)
 527                 return ret;
 528         timer_rate = val;
 529         return count;
 530 }
 531
 532 static struct global_attr timer_rate_attr = __ATTR(timer_rate, 0644,
 533                 show_timer_rate, store_timer_rate);
 534
 535 static ssize_t show_boost(struct kobject *kobj, struct attribute *attr,
 536                           char *buf)
 537 {
 538         return sprintf(buf, "%d\n", boost_val);
 539 }
 540
 541 static ssize_t store_boost(struct kobject *kobj, struct attribute *attr,
 542                            const char *buf, size_t count)
 543 {
 544         int ret;
 545         unsigned long val;
 546
 547         ret = kstrtoul(buf, 0, &val);
 548         if (ret < 0)
 549                 return ret;
 550
 551         boost_val = val;
 552
 553         if (boost_val) {
 554                 trace_cpufreq_interactive_boost("on");
 555                 cpufreq_interactive_boost();
 556         } else {
 557                 trace_cpufreq_interactive_unboost("off");
 558         }
 559
 560         return count;
 561 }
 562
 563 define_one_global_rw(boost);
 564
 565 static ssize_t store_boostpulse(struct kobject *kobj, struct attribute *attr,
 566                                 const char *buf, size_t count)
 567 {
 568         int ret;
 569         unsigned long val;
 570
 571         ret = kstrtoul(buf, 0, &val);
 572         if (ret < 0)
 573                 return ret;
 574
 575         trace_cpufreq_interactive_boost("pulse");
 576         cpufreq_interactive_boost();
 577         return count;
 578 }
 579
 580 static struct global_attr boostpulse =
 581         __ATTR(boostpulse, 0200, NULL, store_boostpulse);
 582
 583 static struct attribute *interactive_attributes[] = {
 584         &hispeed_freq_attr.attr,
 585         &go_hispeed_load_attr.attr,
 586         &above_hispeed_delay.attr,
 587         &min_sample_time_attr.attr,
 588         &timer_rate_attr.attr,
 589         &boost.attr,
 590         &boostpulse.attr,
 591         NULL,
 592 };
 593
 594 static struct attribute_group interactive_attr_group = {
 595         .attrs = interactive_attributes,
 596         .name = "interactive",
 597 };
 598
 599 static int cpufreq_interactive_idle_notifier(struct notifier_block *nb,
 600                                              unsigned long val,
 601                                              void *data)
 602 {
 603         switch (val) {
 604         case IDLE_START:
 605                 cpufreq_interactive_idle_start();
 606                 break;
 607         case IDLE_END:
 608                 cpufreq_interactive_idle_end();
 609                 break;
 610         }
 611
 612         return 0;
 613 }
 614
 615 static struct notifier_block cpufreq_interactive_idle_nb = {
 616         .notifier_call = cpufreq_interactive_idle_notifier,
 617 };
 618
 619 static int cpufreq_governor_interactive(struct cpufreq_policy *policy,
 620                 unsigned int event)
 621 {
 622         int rc;
 623         unsigned int j;
 624         struct cpufreq_interactive_cpuinfo *pcpu;
 625         struct cpufreq_frequency_table *freq_table;
 626
 627         switch (event) {
 628         case CPUFREQ_GOV_START:
 629                 if (!cpu_online(policy->cpu))
 630                         return -EINVAL;
 631
 632                 freq_table =
 633                         cpufreq_frequency_get_table(policy->cpu);
 634                 if (!hispeed_freq)
 635                         hispeed_freq = policy->max;
 636
 637                 for_each_cpu(j, policy->cpus) {
 638                         pcpu = &per_cpu(cpuinfo, j);
 639                         pcpu->policy = policy;
 640                         pcpu->target_freq = policy->cur;
 641                         pcpu->freq_table = freq_table;
 642                         pcpu->target_set_time_in_idle =
 643                                 get_cpu_idle_time_us(j,
 644                                              &pcpu->target_set_time);
 645                         pcpu->floor_freq = pcpu->target_freq;
 646                         pcpu->floor_validate_time =
 647                                 pcpu->target_set_time;
 648                         pcpu->hispeed_validate_time =
 649                                 pcpu->target_set_time;
 650                         pcpu->governor_enabled = 1;
 651                         smp_wmb();
 652                         pcpu->cpu_timer.expires =
 653                                 jiffies + usecs_to_jiffies(timer_rate);
 654                         add_timer_on(&pcpu->cpu_timer, j);
 655                 }
 656
 657                 /*
 658                  * Do not register the idle hook and create sysfs
 659                  * entries if we have already done so.
 660                  */
 661                 if (atomic_inc_return(&active_count) > 1)
 662                         return 0;
 663
 664                 rc = sysfs_create_group(cpufreq_global_kobject,
 665                                 &interactive_attr_group);
 666                 if (rc)
 667                         return rc;
 668
 669                 idle_notifier_register(&cpufreq_interactive_idle_nb);
 670                 break;
 671
 672         case CPUFREQ_GOV_STOP:
 673                 for_each_cpu(j, policy->cpus) {
 674                         pcpu = &per_cpu(cpuinfo, j);
 675                         pcpu->governor_enabled = 0;
 676                         smp_wmb();
 677                         del_timer_sync(&pcpu->cpu_timer);
 678                 }
 679
 680                 if (atomic_dec_return(&active_count) > 0)
 681                         return 0;
 682
 683                 idle_notifier_unregister(&cpufreq_interactive_idle_nb);
 684                 sysfs_remove_group(cpufreq_global_kobject,
 685                                 &interactive_attr_group);
 686
 687                 break;
 688
 689         case CPUFREQ_GOV_LIMITS:
 690                 if (policy->max < policy->cur)
 691                         __cpufreq_driver_target(policy,
 692                                         policy->max, CPUFREQ_RELATION_H);
 693                 else if (policy->min > policy->cur)
 694                         __cpufreq_driver_target(policy,
 695                                         policy->min, CPUFREQ_RELATION_L);
 696                 break;
 697         }
 698         return 0;
 699 }
 700
 701 static int __init cpufreq_interactive_init(void)
 702 {
 703         unsigned int i;
 704         struct cpufreq_interactive_cpuinfo *pcpu;
 705         struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
 706
 707         go_hispeed_load = DEFAULT_GO_HISPEED_LOAD;
 708         min_sample_time = DEFAULT_MIN_SAMPLE_TIME;
 709         above_hispeed_delay_val = DEFAULT_ABOVE_HISPEED_DELAY;
 710         timer_rate = DEFAULT_TIMER_RATE;
 711
 712         /* Initalize per-cpu timers */
 713         for_each_possible_cpu(i) {
 714                 pcpu = &per_cpu(cpuinfo, i);
 715                 if (governidle)
 716                         init_timer(&pcpu->cpu_timer);
 717                 else
 718                         init_timer_deferrable(&pcpu->cpu_timer);
 719                 pcpu->cpu_timer.function = cpufreq_interactive_timer;
 720                 pcpu->cpu_timer.data = i;
 721         }
 722
 723         spin_lock_init(&speedchange_cpumask_lock);
 724         speedchange_task =
 725                 kthread_create(cpufreq_interactive_speedchange_task, NULL,
 726                                "cfinteractive");
 727         if (IS_ERR(speedchange_task))
 728                 return PTR_ERR(speedchange_task);
 729
 730         sched_setscheduler_nocheck(speedchange_task, SCHED_FIFO, &param);
 731         get_task_struct(speedchange_task);
 732
 733         /* NB: wake up so the thread does not look hung to the freezer */
 734         wake_up_process(speedchange_task);
 735
 736         return cpufreq_register_governor(&cpufreq_gov_interactive);
 737 }
 738
 739 #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_INTERACTIVE
 740 fs_initcall(cpufreq_interactive_init);
 741 #else
 742 module_init(cpufreq_interactive_init);
 743 #endif
 744
 745 static void __exit cpufreq_interactive_exit(void)
 746 {
 747         cpufreq_unregister_governor(&cpufreq_gov_interactive);
 748         kthread_stop(speedchange_task);
 749         put_task_struct(speedchange_task);
 750 }
 751
 752 module_exit(cpufreq_interactive_exit);
 753
 754 MODULE_AUTHOR("Mike Chan <mike@android.com>");
 755 MODULE_DESCRIPTION("'cpufreq_interactive' - A cpufreq governor for "
 756         "Latency sensitive workloads");
 757 MODULE_LICENSE("GPL");