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/mutex.h>
  24 #include <linux/sched.h>
  25 #include <linux/sched/rt.h>
  26 #include <linux/tick.h>
  27 #include <linux/time.h>
  28 #include <linux/timer.h>
  29 #include <linux/workqueue.h>
  30 #include <linux/kthread.h>
  31 #include <linux/mutex.h>
  32 #include <linux/slab.h>
  33 #include <asm/cputime.h>
  34
  35 #define CREATE_TRACE_POINTS
  36 #include <trace/events/cpufreq_interactive.h>
  37
  38 static atomic_t active_count = ATOMIC_INIT(0);
  39
  40 struct cpufreq_interactive_cpuinfo {
  41         struct timer_list cpu_timer;
  42         int timer_idlecancel;
  43         u64 time_in_idle;
  44         u64 idle_exit_time;
  45         u64 timer_run_time;
  46         int idling;
  47         u64 target_set_time;
  48         u64 target_set_time_in_idle;
  49         struct cpufreq_policy *policy;
  50         struct cpufreq_frequency_table *freq_table;
  51         unsigned int target_freq;
  52         unsigned int floor_freq;
  53         u64 floor_validate_time;
  54         u64 hispeed_validate_time;
  55         int governor_enabled;
  56 };
  57
  58 static DEFINE_PER_CPU(struct cpufreq_interactive_cpuinfo, cpuinfo);
  59
  60 /* realtime thread handles frequency scaling */
  61 static struct task_struct *speedchange_task;
  62 static cpumask_t speedchange_cpumask;
  63 static spinlock_t speedchange_cpumask_lock;
  64
  65 /* Hi speed to bump to from lo speed when load burst (default max) */
  66 static u64 hispeed_freq;
  67
  68 /* Go to hi speed when CPU load at or above this value. */
  69 #define DEFAULT_GO_HISPEED_LOAD 85
  70 static unsigned long go_hispeed_load;
  71
  72 /*
  73  * The minimum amount of time to spend at a frequency before we can ramp down.
  74  */
  75 #define DEFAULT_MIN_SAMPLE_TIME (80 * USEC_PER_MSEC)
  76 static unsigned long min_sample_time;
  77
  78 /*
  79  * The sample rate of the timer used to increase frequency
  80  */
  81 #define DEFAULT_TIMER_RATE (20 * USEC_PER_MSEC)
  82 static unsigned long timer_rate;
  83
  84 /*
  85  * Wait this long before raising speed above hispeed, by default a single
  86  * timer interval.
  87  */
  88 #define DEFAULT_ABOVE_HISPEED_DELAY DEFAULT_TIMER_RATE
  89 static unsigned long above_hispeed_delay_val;
  90
  91 /*
  92  * Non-zero means longer-term speed boost active.
  93  */
  94
  95 static int boost_val;
  96
  97 static int cpufreq_governor_interactive(struct cpufreq_policy *policy,
  98                 unsigned int event);
  99
 100 #ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_INTERACTIVE
 101 static
 102 #endif
 103 struct cpufreq_governor cpufreq_gov_interactive = {
 104         .name = "interactive",
 105         .governor = cpufreq_governor_interactive,
 106         .max_transition_latency = 10000000,
 107         .owner = THIS_MODULE,
 108 };
 109
 110 static void cpufreq_interactive_timer(unsigned long data)
 111 {
 112         unsigned int delta_idle;
 113         unsigned int delta_time;
 114         int cpu_load;
 115         int load_since_change;
 116         u64 time_in_idle;
 117         u64 idle_exit_time;
 118         struct cpufreq_interactive_cpuinfo *pcpu =
 119                 &per_cpu(cpuinfo, data);
 120         u64 now_idle;
 121         unsigned int new_freq;
 122         unsigned int index;
 123         unsigned long flags;
 124
 125         smp_rmb();
 126
 127         if (!pcpu->governor_enabled)
 128                 goto exit;
 129
 130         /*
 131          * Once pcpu->timer_run_time is updated to >= pcpu->idle_exit_time,
 132          * this lets idle exit know the current idle time sample has
 133          * been processed, and idle exit can generate a new sample and
 134          * re-arm the timer.  This prevents a concurrent idle
 135          * exit on that CPU from writing a new set of info at the same time
 136          * the timer function runs (the timer function can't use that info
 137          * until more time passes).
 138          */
 139         time_in_idle = pcpu->time_in_idle;
 140         idle_exit_time = pcpu->idle_exit_time;
 141         now_idle = get_cpu_idle_time_us(data, &pcpu->timer_run_time);
 142         smp_wmb();
 143
 144         /* If we raced with cancelling a timer, skip. */
 145         if (!idle_exit_time)
 146                 goto exit;
 147
 148         delta_idle = (unsigned int)(now_idle - time_in_idle);
 149         delta_time = (unsigned int)(pcpu->timer_run_time - idle_exit_time);
 150
 151         /*
 152          * If timer ran less than 1ms after short-term sample started, retry.
 153          */
 154         if (delta_time < 1000)
 155                 goto rearm;
 156
 157         if (delta_idle > delta_time)
 158                 cpu_load = 0;
 159         else
 160                 cpu_load = 100 * (delta_time - delta_idle) / delta_time;
 161
 162         delta_idle = (unsigned int)(now_idle - pcpu->target_set_time_in_idle);
 163         delta_time = (unsigned int)(pcpu->timer_run_time -
 164                                     pcpu->target_set_time);
 165
 166         if ((delta_time == 0) || (delta_idle > delta_time))
 167                 load_since_change = 0;
 168         else
 169                 load_since_change =
 170                         100 * (delta_time - delta_idle) / delta_time;
 171
 172         /*
 173          * Choose greater of short-term load (since last idle timer
 174          * started or timer function re-armed itself) or long-term load
 175          * (since last frequency change).
 176          */
 177         if (load_since_change > cpu_load)
 178                 cpu_load = load_since_change;
 179
 180         if (cpu_load >= go_hispeed_load || boost_val) {
 181                 if (pcpu->target_freq <= pcpu->policy->min) {
 182                         new_freq = hispeed_freq;
 183                 } else {
 184                         new_freq = pcpu->policy->max * cpu_load / 100;
 185
 186                         if (new_freq < hispeed_freq)
 187                                 new_freq = hispeed_freq;
 188
 189                         if (pcpu->target_freq == hispeed_freq &&
 190                             new_freq > hispeed_freq &&
 191                             pcpu->timer_run_time - pcpu->hispeed_validate_time
 192                             < above_hispeed_delay_val) {
 193                                 trace_cpufreq_interactive_notyet(data, cpu_load,
 194                                                                  pcpu->target_freq,
 195                                                                  new_freq);
 196                                 goto rearm;
 197                         }
 198                 }
 199         } else {
 200                 new_freq = pcpu->policy->max * cpu_load / 100;
 201         }
 202
 203         if (new_freq <= hispeed_freq)
 204                 pcpu->hispeed_validate_time = pcpu->timer_run_time;
 205
 206         if (cpufreq_frequency_table_target(pcpu->policy, pcpu->freq_table,
 207                                            new_freq, CPUFREQ_RELATION_H,
 208                                            &index)) {
 209                 pr_warn_once("timer %d: cpufreq_frequency_table_target error\n",
 210                              (int) data);
 211                 goto rearm;
 212         }
 213
 214         new_freq = pcpu->freq_table[index].frequency;
 215
 216         /*
 217          * Do not scale below floor_freq unless we have been at or above the
 218          * floor frequency for the minimum sample time since last validated.
 219          */
 220         if (new_freq < pcpu->floor_freq) {
 221                 if (pcpu->timer_run_time - pcpu->floor_validate_time
 222                     < min_sample_time) {
 223                         trace_cpufreq_interactive_notyet(data, cpu_load,
 224                                          pcpu->target_freq, new_freq);
 225                         goto rearm;
 226                 }
 227         }
 228
 229         pcpu->floor_freq = new_freq;
 230         pcpu->floor_validate_time = pcpu->timer_run_time;
 231
 232         if (pcpu->target_freq == new_freq) {
 233                 trace_cpufreq_interactive_already(data, cpu_load,
 234                                                   pcpu->target_freq, new_freq);
 235                 goto rearm_if_notmax;
 236         }
 237
 238         trace_cpufreq_interactive_target(data, cpu_load, pcpu->target_freq,
 239                                          new_freq);
 240         pcpu->target_set_time_in_idle = now_idle;
 241         pcpu->target_set_time = pcpu->timer_run_time;
 242
 243         pcpu->target_freq = new_freq;
 244         spin_lock_irqsave(&speedchange_cpumask_lock, flags);
 245         cpumask_set_cpu(data, &speedchange_cpumask);
 246         spin_unlock_irqrestore(&speedchange_cpumask_lock, flags);
 247         wake_up_process(speedchange_task);
 248
 249 rearm_if_notmax:
 250         /*
 251          * Already set max speed and don't see a need to change that,
 252          * wait until next idle to re-evaluate, don't need timer.
 253          */
 254         if (pcpu->target_freq == pcpu->policy->max)
 255                 goto exit;
 256
 257 rearm:
 258         if (!timer_pending(&pcpu->cpu_timer)) {
 259                 /*
 260                  * If already at min: if that CPU is idle, don't set timer.
 261                  * Else cancel the timer if that CPU goes idle.  We don't
 262                  * need to re-evaluate speed until the next idle exit.
 263                  */
 264                 if (pcpu->target_freq == pcpu->policy->min) {
 265                         smp_rmb();
 266
 267                         if (pcpu->idling)
 268                                 goto exit;
 269
 270                         pcpu->timer_idlecancel = 1;
 271                 }
 272
 273                 pcpu->time_in_idle = get_cpu_idle_time_us(
 274                         data, &pcpu->idle_exit_time);
 275                 mod_timer(&pcpu->cpu_timer,
 276                           jiffies + usecs_to_jiffies(timer_rate));
 277         }
 278
 279 exit:
 280         return;
 281 }
 282
 283 static void cpufreq_interactive_idle_start(void)
 284 {
 285         struct cpufreq_interactive_cpuinfo *pcpu =
 286                 &per_cpu(cpuinfo, smp_processor_id());
 287         int pending;
 288
 289         if (!pcpu->governor_enabled)
 290                 return;
 291
 292         pcpu->idling = 1;
 293         smp_wmb();
 294         pending = timer_pending(&pcpu->cpu_timer);
 295
 296         if (pcpu->target_freq != pcpu->policy->min) {
 297 #ifdef CONFIG_SMP
 298                 /*
 299                  * Entering idle while not at lowest speed.  On some
 300                  * platforms this can hold the other CPU(s) at that speed
 301                  * even though the CPU is idle. Set a timer to re-evaluate
 302                  * speed so this idle CPU doesn't hold the other CPUs above
 303                  * min indefinitely.  This should probably be a quirk of
 304                  * the CPUFreq driver.
 305                  */
 306                 if (!pending) {
 307                         pcpu->time_in_idle = get_cpu_idle_time_us(
 308                                 smp_processor_id(), &pcpu->idle_exit_time);
 309                         pcpu->timer_idlecancel = 0;
 310                         mod_timer(&pcpu->cpu_timer,
 311                                   jiffies + usecs_to_jiffies(timer_rate));
 312                 }
 313 #endif
 314         } else {
 315                 /*
 316                  * If at min speed and entering idle after load has
 317                  * already been evaluated, and a timer has been set just in
 318                  * case the CPU suddenly goes busy, cancel that timer.  The
 319                  * CPU didn't go busy; we'll recheck things upon idle exit.
 320                  */
 321                 if (pending && pcpu->timer_idlecancel) {
 322                         del_timer(&pcpu->cpu_timer);
 323                         /*
 324                          * Ensure last timer run time is after current idle
 325                          * sample start time, so next idle exit will always
 326                          * start a new idle sampling period.
 327                          */
 328                         pcpu->idle_exit_time = 0;
 329                         pcpu->timer_idlecancel = 0;
 330                 }
 331         }
 332
 333 }
 334
 335 static void cpufreq_interactive_idle_end(void)
 336 {
 337         struct cpufreq_interactive_cpuinfo *pcpu =
 338                 &per_cpu(cpuinfo, smp_processor_id());
 339
 340         if (!pcpu->governor_enabled)
 341                 return;
 342
 343         pcpu->idling = 0;
 344         smp_wmb();
 345
 346         /*
 347          * Arm the timer for 1-2 ticks later if not already, and if the timer
 348          * function has already processed the previous load sampling
 349          * interval.  (If the timer is not pending but has not processed
 350          * the previous interval, it is probably racing with us on another
 351          * CPU.  Let it compute load based on the previous sample and then
 352          * re-arm the timer for another interval when it's done, rather
 353          * than updating the interval start time to be "now", which doesn't
 354          * give the timer function enough time to make a decision on this
 355          * run.)
 356          */
 357         if (timer_pending(&pcpu->cpu_timer) == 0 &&
 358             pcpu->timer_run_time >= pcpu->idle_exit_time &&
 359             pcpu->governor_enabled) {
 360                 pcpu->time_in_idle =
 361                         get_cpu_idle_time_us(smp_processor_id(),
 362                                              &pcpu->idle_exit_time);
 363                 pcpu->timer_idlecancel = 0;
 364                 mod_timer(&pcpu->cpu_timer,
 365                           jiffies + usecs_to_jiffies(timer_rate));
 366         }
 367
 368 }
 369
 370 static int cpufreq_interactive_speedchange_task(void *data)
 371 {
 372         unsigned int cpu;
 373         cpumask_t tmp_mask;
 374         unsigned long flags;
 375         struct cpufreq_interactive_cpuinfo *pcpu;
 376
 377         while (1) {
 378                 set_current_state(TASK_INTERRUPTIBLE);
 379                 spin_lock_irqsave(&speedchange_cpumask_lock, flags);
 380
 381                 if (cpumask_empty(&speedchange_cpumask)) {
 382                         spin_unlock_irqrestore(&speedchange_cpumask_lock,
 383                                                flags);
 384                         schedule();
 385
 386                         if (kthread_should_stop())
 387                                 break;
 388
 389                         spin_lock_irqsave(&speedchange_cpumask_lock, flags);
 390                 }
 391
 392                 set_current_state(TASK_RUNNING);
 393                 tmp_mask = speedchange_cpumask;
 394                 cpumask_clear(&speedchange_cpumask);
 395                 spin_unlock_irqrestore(&speedchange_cpumask_lock, flags);
 396
 397                 for_each_cpu(cpu, &tmp_mask) {
 398                         unsigned int j;
 399                         unsigned int max_freq = 0;
 400
 401                         pcpu = &per_cpu(cpuinfo, cpu);
 402                         smp_rmb();
 403
 404                         if (!pcpu->governor_enabled)
 405                                 continue;
 406
 407                         for_each_cpu(j, pcpu->policy->cpus) {
 408                                 struct cpufreq_interactive_cpuinfo *pjcpu =
 409                                         &per_cpu(cpuinfo, j);
 410
 411                                 if (pjcpu->target_freq > max_freq)
 412                                         max_freq = pjcpu->target_freq;
 413                         }
 414
 415                         if (max_freq != pcpu->policy->cur)
 416                                 __cpufreq_driver_target(pcpu->policy,
 417                                                         max_freq,
 418                                                         CPUFREQ_RELATION_H);
 419                         trace_cpufreq_interactive_setspeed(cpu,
 420                                                      pcpu->target_freq,
 421                                                      pcpu->policy->cur);
 422                 }
 423         }
 424
 425         return 0;
 426 }
 427
 428 static void cpufreq_interactive_boost(void)
 429 {
 430         int i;
 431         int anyboost = 0;
 432         unsigned long flags;
 433         struct cpufreq_interactive_cpuinfo *pcpu;
 434
 435         spin_lock_irqsave(&speedchange_cpumask_lock, flags);
 436
 437         for_each_online_cpu(i) {
 438                 pcpu = &per_cpu(cpuinfo, i);
 439
 440                 if (pcpu->target_freq < hispeed_freq) {
 441                         pcpu->target_freq = hispeed_freq;
 442                         cpumask_set_cpu(i, &speedchange_cpumask);
 443                         pcpu->target_set_time_in_idle =
 444                                 get_cpu_idle_time_us(i, &pcpu->target_set_time);
 445                         pcpu->hispeed_validate_time = pcpu->target_set_time;
 446                         anyboost = 1;
 447                 }
 448
 449                 /*
 450                  * Set floor freq and (re)start timer for when last
 451                  * validated.
 452                  */
 453
 454                 pcpu->floor_freq = hispeed_freq;
 455                 pcpu->floor_validate_time = ktime_to_us(ktime_get());
 456         }
 457
 458         spin_unlock_irqrestore(&speedchange_cpumask_lock, flags);
 459
 460         if (anyboost)
 461                 wake_up_process(speedchange_task);
 462 }
 463
 464 static ssize_t show_hispeed_freq(struct kobject *kobj,
 465                                  struct attribute *attr, char *buf)
 466 {
 467         return sprintf(buf, "%llu\n", hispeed_freq);
 468 }
 469
 470 static ssize_t store_hispeed_freq(struct kobject *kobj,
 471                                   struct attribute *attr, const char *buf,
 472                                   size_t count)
 473 {
 474         int ret;
 475         u64 val;
 476
 477         ret = strict_strtoull(buf, 0, &val);
 478         if (ret < 0)
 479                 return ret;
 480         hispeed_freq = val;
 481         return count;
 482 }
 483
 484 static struct global_attr hispeed_freq_attr = __ATTR(hispeed_freq, 0644,
 485                 show_hispeed_freq, store_hispeed_freq);
 486
 487
 488 static ssize_t show_go_hispeed_load(struct kobject *kobj,
 489                                      struct attribute *attr, char *buf)
 490 {
 491         return sprintf(buf, "%lu\n", go_hispeed_load);
 492 }
 493
 494 static ssize_t store_go_hispeed_load(struct kobject *kobj,
 495                         struct attribute *attr, const char *buf, size_t count)
 496 {
 497         int ret;
 498         unsigned long val;
 499
 500         ret = strict_strtoul(buf, 0, &val);
 501         if (ret < 0)
 502                 return ret;
 503         go_hispeed_load = val;
 504         return count;
 505 }
 506
 507 static struct global_attr go_hispeed_load_attr = __ATTR(go_hispeed_load, 0644,
 508                 show_go_hispeed_load, store_go_hispeed_load);
 509
 510 static ssize_t show_min_sample_time(struct kobject *kobj,
 511                                 struct attribute *attr, char *buf)
 512 {
 513         return sprintf(buf, "%lu\n", min_sample_time);
 514 }
 515
 516 static ssize_t store_min_sample_time(struct kobject *kobj,
 517                         struct attribute *attr, const char *buf, size_t count)
 518 {
 519         int ret;
 520         unsigned long val;
 521
 522         ret = strict_strtoul(buf, 0, &val);
 523         if (ret < 0)
 524                 return ret;
 525         min_sample_time = val;
 526         return count;
 527 }
 528
 529 static struct global_attr min_sample_time_attr = __ATTR(min_sample_time, 0644,
 530                 show_min_sample_time, store_min_sample_time);
 531
 532 static ssize_t show_above_hispeed_delay(struct kobject *kobj,
 533                                         struct attribute *attr, char *buf)
 534 {
 535         return sprintf(buf, "%lu\n", above_hispeed_delay_val);
 536 }
 537
 538 static ssize_t store_above_hispeed_delay(struct kobject *kobj,
 539                                          struct attribute *attr,
 540                                          const char *buf, size_t count)
 541 {
 542         int ret;
 543         unsigned long val;
 544
 545         ret = strict_strtoul(buf, 0, &val);
 546         if (ret < 0)
 547                 return ret;
 548         above_hispeed_delay_val = val;
 549         return count;
 550 }
 551
 552 define_one_global_rw(above_hispeed_delay);
 553
 554 static ssize_t show_timer_rate(struct kobject *kobj,
 555                         struct attribute *attr, char *buf)
 556 {
 557         return sprintf(buf, "%lu\n", timer_rate);
 558 }
 559
 560 static ssize_t store_timer_rate(struct kobject *kobj,
 561                         struct attribute *attr, const char *buf, size_t count)
 562 {
 563         int ret;
 564         unsigned long val;
 565
 566         ret = strict_strtoul(buf, 0, &val);
 567         if (ret < 0)
 568                 return ret;
 569         timer_rate = val;
 570         return count;
 571 }
 572
 573 static struct global_attr timer_rate_attr = __ATTR(timer_rate, 0644,
 574                 show_timer_rate, store_timer_rate);
 575
 576 static ssize_t show_boost(struct kobject *kobj, struct attribute *attr,
 577                           char *buf)
 578 {
 579         return sprintf(buf, "%d\n", boost_val);
 580 }
 581
 582 static ssize_t store_boost(struct kobject *kobj, struct attribute *attr,
 583                            const char *buf, size_t count)
 584 {
 585         int ret;
 586         unsigned long val;
 587
 588         ret = kstrtoul(buf, 0, &val);
 589         if (ret < 0)
 590                 return ret;
 591
 592         boost_val = val;
 593
 594         if (boost_val) {
 595                 trace_cpufreq_interactive_boost("on");
 596                 cpufreq_interactive_boost();
 597         } else {
 598                 trace_cpufreq_interactive_unboost("off");
 599         }
 600
 601         return count;
 602 }
 603
 604 define_one_global_rw(boost);
 605
 606 static ssize_t store_boostpulse(struct kobject *kobj, struct attribute *attr,
 607                                 const char *buf, size_t count)
 608 {
 609         int ret;
 610         unsigned long val;
 611
 612         ret = kstrtoul(buf, 0, &val);
 613         if (ret < 0)
 614                 return ret;
 615
 616         trace_cpufreq_interactive_boost("pulse");
 617         cpufreq_interactive_boost();
 618         return count;
 619 }
 620
 621 static struct global_attr boostpulse =
 622         __ATTR(boostpulse, 0200, NULL, store_boostpulse);
 623
 624 static struct attribute *interactive_attributes[] = {
 625         &hispeed_freq_attr.attr,
 626         &go_hispeed_load_attr.attr,
 627         &above_hispeed_delay.attr,
 628         &min_sample_time_attr.attr,
 629         &timer_rate_attr.attr,
 630         &boost.attr,
 631         &boostpulse.attr,
 632         NULL,
 633 };
 634
 635 static struct attribute_group interactive_attr_group = {
 636         .attrs = interactive_attributes,
 637         .name = "interactive",
 638 };
 639
 640 static int cpufreq_interactive_idle_notifier(struct notifier_block *nb,
 641                                              unsigned long val,
 642                                              void *data)
 643 {
 644         switch (val) {
 645         case IDLE_START:
 646                 cpufreq_interactive_idle_start();
 647                 break;
 648         case IDLE_END:
 649                 cpufreq_interactive_idle_end();
 650                 break;
 651         }
 652
 653         return 0;
 654 }
 655
 656 static struct notifier_block cpufreq_interactive_idle_nb = {
 657         .notifier_call = cpufreq_interactive_idle_notifier,
 658 };
 659
 660 static int cpufreq_governor_interactive(struct cpufreq_policy *policy,
 661                 unsigned int event)
 662 {
 663         int rc;
 664         unsigned int j;
 665         struct cpufreq_interactive_cpuinfo *pcpu;
 666         struct cpufreq_frequency_table *freq_table;
 667
 668         switch (event) {
 669         case CPUFREQ_GOV_START:
 670                 if (!cpu_online(policy->cpu))
 671                         return -EINVAL;
 672
 673                 freq_table =
 674                         cpufreq_frequency_get_table(policy->cpu);
 675
 676                 for_each_cpu(j, policy->cpus) {
 677                         pcpu = &per_cpu(cpuinfo, j);
 678                         pcpu->policy = policy;
 679                         pcpu->target_freq = policy->cur;
 680                         pcpu->freq_table = freq_table;
 681                         pcpu->target_set_time_in_idle =
 682                                 get_cpu_idle_time_us(j,
 683                                              &pcpu->target_set_time);
 684                         pcpu->floor_freq = pcpu->target_freq;
 685                         pcpu->floor_validate_time =
 686                                 pcpu->target_set_time;
 687                         pcpu->hispeed_validate_time =
 688                                 pcpu->target_set_time;
 689                         pcpu->governor_enabled = 1;
 690                         smp_wmb();
 691                 }
 692
 693                 if (!hispeed_freq)
 694                         hispeed_freq = policy->max;
 695
 696                 /*
 697                  * Do not register the idle hook and create sysfs
 698                  * entries if we have already done so.
 699                  */
 700                 if (atomic_inc_return(&active_count) > 1)
 701                         return 0;
 702
 703                 rc = sysfs_create_group(cpufreq_global_kobject,
 704                                 &interactive_attr_group);
 705                 if (rc)
 706                         return rc;
 707
 708                 idle_notifier_register(&cpufreq_interactive_idle_nb);
 709                 break;
 710
 711         case CPUFREQ_GOV_STOP:
 712                 for_each_cpu(j, policy->cpus) {
 713                         pcpu = &per_cpu(cpuinfo, j);
 714                         pcpu->governor_enabled = 0;
 715                         smp_wmb();
 716                         del_timer_sync(&pcpu->cpu_timer);
 717
 718                         /*
 719                          * Reset idle exit time since we may cancel the timer
 720                          * before it can run after the last idle exit time,
 721                          * to avoid tripping the check in idle exit for a timer
 722                          * that is trying to run.
 723                          */
 724                         pcpu->idle_exit_time = 0;
 725                 }
 726
 727                 if (atomic_dec_return(&active_count) > 0)
 728                         return 0;
 729
 730                 idle_notifier_unregister(&cpufreq_interactive_idle_nb);
 731                 sysfs_remove_group(cpufreq_global_kobject,
 732                                 &interactive_attr_group);
 733
 734                 break;
 735
 736         case CPUFREQ_GOV_LIMITS:
 737                 if (policy->max < policy->cur)
 738                         __cpufreq_driver_target(policy,
 739                                         policy->max, CPUFREQ_RELATION_H);
 740                 else if (policy->min > policy->cur)
 741                         __cpufreq_driver_target(policy,
 742                                         policy->min, CPUFREQ_RELATION_L);
 743                 break;
 744         }
 745         return 0;
 746 }
 747
 748 static int __init cpufreq_interactive_init(void)
 749 {
 750         unsigned int i;
 751         struct cpufreq_interactive_cpuinfo *pcpu;
 752         struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
 753
 754         go_hispeed_load = DEFAULT_GO_HISPEED_LOAD;
 755         min_sample_time = DEFAULT_MIN_SAMPLE_TIME;
 756         above_hispeed_delay_val = DEFAULT_ABOVE_HISPEED_DELAY;
 757         timer_rate = DEFAULT_TIMER_RATE;
 758
 759         /* Initalize per-cpu timers */
 760         for_each_possible_cpu(i) {
 761                 pcpu = &per_cpu(cpuinfo, i);
 762                 init_timer(&pcpu->cpu_timer);
 763                 pcpu->cpu_timer.function = cpufreq_interactive_timer;
 764                 pcpu->cpu_timer.data = i;
 765         }
 766
 767         spin_lock_init(&speedchange_cpumask_lock);
 768         speedchange_task =
 769                 kthread_create(cpufreq_interactive_speedchange_task, NULL,
 770                                "cfinteractive");
 771         if (IS_ERR(speedchange_task))
 772                 return PTR_ERR(speedchange_task);
 773
 774         sched_setscheduler_nocheck(speedchange_task, SCHED_FIFO, &param);
 775         get_task_struct(speedchange_task);
 776
 777         /* NB: wake up so the thread does not look hung to the freezer */
 778         wake_up_process(speedchange_task);
 779
 780         return cpufreq_register_governor(&cpufreq_gov_interactive);
 781 }
 782
 783 #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_INTERACTIVE
 784 fs_initcall(cpufreq_interactive_init);
 785 #else
 786 module_init(cpufreq_interactive_init);
 787 #endif
 788
 789 static void __exit cpufreq_interactive_exit(void)
 790 {
 791         cpufreq_unregister_governor(&cpufreq_gov_interactive);
 792         kthread_stop(speedchange_task);
 793         put_task_struct(speedchange_task);
 794 }
 795
 796 module_exit(cpufreq_interactive_exit);
 797
 798 MODULE_AUTHOR("Mike Chan <mike@android.com>");
 799 MODULE_DESCRIPTION("'cpufreq_interactive' - A cpufreq governor for "
 800         "Latency sensitive workloads");
 801 MODULE_LICENSE("GPL");