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