1 /* 2 * CPUFreq governor based on scheduler-provided CPU utilization data. 3 * 4 * Copyright (C) 2016, Intel Corporation 5 * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 */ 11 12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 13 14 #include <linux/cpufreq.h> 15 #include <linux/kthread.h> 16 #include <uapi/linux/sched/types.h> 17 #include <linux/slab.h> 18 #include <trace/events/power.h> 19 20 #include "sched.h" 21 22 #define SUGOV_KTHREAD_PRIORITY 50 23 24 struct sugov_tunables { 25 struct gov_attr_set attr_set; 26 unsigned int rate_limit_us; 27 }; 28 29 struct sugov_policy { 30 struct cpufreq_policy *policy; 31 32 struct sugov_tunables *tunables; 33 struct list_head tunables_hook; 34 35 raw_spinlock_t update_lock; /* For shared policies */ 36 u64 last_freq_update_time; 37 s64 freq_update_delay_ns; 38 unsigned int next_freq; 39 unsigned int cached_raw_freq; 40 41 /* The next fields are only needed if fast switch cannot be used. */ 42 struct irq_work irq_work; 43 struct kthread_work work; 44 struct mutex work_lock; 45 struct kthread_worker worker; 46 struct task_struct *thread; 47 bool work_in_progress; 48 49 bool need_freq_update; 50 }; 51 52 struct sugov_cpu { 53 struct update_util_data update_util; 54 struct sugov_policy *sg_policy; 55 unsigned int cpu; 56 57 bool iowait_boost_pending; 58 unsigned int iowait_boost; 59 unsigned int iowait_boost_max; 60 u64 last_update; 61 62 /* The fields below are only needed when sharing a policy. */ 63 unsigned long util; 64 unsigned long max; 65 unsigned int flags; 66 67 /* The field below is for single-CPU policies only. */ 68 #ifdef CONFIG_NO_HZ_COMMON 69 unsigned long saved_idle_calls; 70 #endif 71 }; 72 73 static DEFINE_PER_CPU(struct sugov_cpu, sugov_cpu); 74 75 /************************ Governor internals ***********************/ 76 77 static bool sugov_should_update_freq(struct sugov_policy *sg_policy, u64 time) 78 { 79 s64 delta_ns; 80 81 /* 82 * Since cpufreq_update_util() is called with rq->lock held for 83 * the @target_cpu, our per-cpu data is fully serialized. 84 * 85 * However, drivers cannot in general deal with cross-cpu 86 * requests, so while get_next_freq() will work, our 87 * sugov_update_commit() call may not for the fast switching platforms. 88 * 89 * Hence stop here for remote requests if they aren't supported 90 * by the hardware, as calculating the frequency is pointless if 91 * we cannot in fact act on it. 92 * 93 * For the slow switching platforms, the kthread is always scheduled on 94 * the right set of CPUs and any CPU can find the next frequency and 95 * schedule the kthread. 96 */ 97 if (sg_policy->policy->fast_switch_enabled && 98 !cpufreq_can_do_remote_dvfs(sg_policy->policy)) 99 return false; 100 101 if (sg_policy->work_in_progress) 102 return false; 103 104 if (unlikely(sg_policy->need_freq_update)) { 105 sg_policy->need_freq_update = false; 106 /* 107 * This happens when limits change, so forget the previous 108 * next_freq value and force an update. 109 */ 110 sg_policy->next_freq = UINT_MAX; 111 return true; 112 } 113 114 delta_ns = time - sg_policy->last_freq_update_time; 115 return delta_ns >= sg_policy->freq_update_delay_ns; 116 } 117 118 static void sugov_update_commit(struct sugov_policy *sg_policy, u64 time, 119 unsigned int next_freq) 120 { 121 struct cpufreq_policy *policy = sg_policy->policy; 122 123 if (sg_policy->next_freq == next_freq) 124 return; 125 126 sg_policy->next_freq = next_freq; 127 sg_policy->last_freq_update_time = time; 128 129 if (policy->fast_switch_enabled) { 130 next_freq = cpufreq_driver_fast_switch(policy, next_freq); 131 if (!next_freq) 132 return; 133 134 policy->cur = next_freq; 135 trace_cpu_frequency(next_freq, smp_processor_id()); 136 } else { 137 sg_policy->work_in_progress = true; 138 irq_work_queue(&sg_policy->irq_work); 139 } 140 } 141 142 /** 143 * get_next_freq - Compute a new frequency for a given cpufreq policy. 144 * @sg_policy: schedutil policy object to compute the new frequency for. 145 * @util: Current CPU utilization. 146 * @max: CPU capacity. 147 * 148 * If the utilization is frequency-invariant, choose the new frequency to be 149 * proportional to it, that is 150 * 151 * next_freq = C * max_freq * util / max 152 * 153 * Otherwise, approximate the would-be frequency-invariant utilization by 154 * util_raw * (curr_freq / max_freq) which leads to 155 * 156 * next_freq = C * curr_freq * util_raw / max 157 * 158 * Take C = 1.25 for the frequency tipping point at (util / max) = 0.8. 159 * 160 * The lowest driver-supported frequency which is equal or greater than the raw 161 * next_freq (as calculated above) is returned, subject to policy min/max and 162 * cpufreq driver limitations. 163 */ 164 static unsigned int get_next_freq(struct sugov_policy *sg_policy, 165 unsigned long util, unsigned long max) 166 { 167 struct cpufreq_policy *policy = sg_policy->policy; 168 unsigned int freq = arch_scale_freq_invariant() ? 169 policy->cpuinfo.max_freq : policy->cur; 170 171 freq = (freq + (freq >> 2)) * util / max; 172 173 if (freq == sg_policy->cached_raw_freq && sg_policy->next_freq != UINT_MAX) 174 return sg_policy->next_freq; 175 sg_policy->cached_raw_freq = freq; 176 return cpufreq_driver_resolve_freq(policy, freq); 177 } 178 179 static void sugov_get_util(unsigned long *util, unsigned long *max, int cpu) 180 { 181 struct rq *rq = cpu_rq(cpu); 182 unsigned long cfs_max; 183 184 cfs_max = arch_scale_cpu_capacity(NULL, cpu); 185 186 *util = min(rq->cfs.avg.util_avg, cfs_max); 187 *max = cfs_max; 188 } 189 190 static void sugov_set_iowait_boost(struct sugov_cpu *sg_cpu, u64 time, 191 unsigned int flags) 192 { 193 if (flags & SCHED_CPUFREQ_IOWAIT) { 194 if (sg_cpu->iowait_boost_pending) 195 return; 196 197 sg_cpu->iowait_boost_pending = true; 198 199 if (sg_cpu->iowait_boost) { 200 sg_cpu->iowait_boost <<= 1; 201 if (sg_cpu->iowait_boost > sg_cpu->iowait_boost_max) 202 sg_cpu->iowait_boost = sg_cpu->iowait_boost_max; 203 } else { 204 sg_cpu->iowait_boost = sg_cpu->sg_policy->policy->min; 205 } 206 } else if (sg_cpu->iowait_boost) { 207 s64 delta_ns = time - sg_cpu->last_update; 208 209 /* Clear iowait_boost if the CPU apprears to have been idle. */ 210 if (delta_ns > TICK_NSEC) { 211 sg_cpu->iowait_boost = 0; 212 sg_cpu->iowait_boost_pending = false; 213 } 214 } 215 } 216 217 static void sugov_iowait_boost(struct sugov_cpu *sg_cpu, unsigned long *util, 218 unsigned long *max) 219 { 220 unsigned int boost_util, boost_max; 221 222 if (!sg_cpu->iowait_boost) 223 return; 224 225 if (sg_cpu->iowait_boost_pending) { 226 sg_cpu->iowait_boost_pending = false; 227 } else { 228 sg_cpu->iowait_boost >>= 1; 229 if (sg_cpu->iowait_boost < sg_cpu->sg_policy->policy->min) { 230 sg_cpu->iowait_boost = 0; 231 return; 232 } 233 } 234 235 boost_util = sg_cpu->iowait_boost; 236 boost_max = sg_cpu->iowait_boost_max; 237 238 if (*util * boost_max < *max * boost_util) { 239 *util = boost_util; 240 *max = boost_max; 241 } 242 } 243 244 #ifdef CONFIG_NO_HZ_COMMON 245 static bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu) 246 { 247 unsigned long idle_calls = tick_nohz_get_idle_calls(); 248 bool ret = idle_calls == sg_cpu->saved_idle_calls; 249 250 sg_cpu->saved_idle_calls = idle_calls; 251 return ret; 252 } 253 #else 254 static inline bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu) { return false; } 255 #endif /* CONFIG_NO_HZ_COMMON */ 256 257 static void sugov_update_single(struct update_util_data *hook, u64 time, 258 unsigned int flags) 259 { 260 struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util); 261 struct sugov_policy *sg_policy = sg_cpu->sg_policy; 262 struct cpufreq_policy *policy = sg_policy->policy; 263 unsigned long util, max; 264 unsigned int next_f; 265 bool busy; 266 267 sugov_set_iowait_boost(sg_cpu, time, flags); 268 sg_cpu->last_update = time; 269 270 if (!sugov_should_update_freq(sg_policy, time)) 271 return; 272 273 busy = sugov_cpu_is_busy(sg_cpu); 274 275 if (flags & SCHED_CPUFREQ_RT_DL) { 276 next_f = policy->cpuinfo.max_freq; 277 } else { 278 sugov_get_util(&util, &max, sg_cpu->cpu); 279 sugov_iowait_boost(sg_cpu, &util, &max); 280 next_f = get_next_freq(sg_policy, util, max); 281 /* 282 * Do not reduce the frequency if the CPU has not been idle 283 * recently, as the reduction is likely to be premature then. 284 */ 285 if (busy && next_f < sg_policy->next_freq) 286 next_f = sg_policy->next_freq; 287 } 288 sugov_update_commit(sg_policy, time, next_f); 289 } 290 291 static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu, u64 time) 292 { 293 struct sugov_policy *sg_policy = sg_cpu->sg_policy; 294 struct cpufreq_policy *policy = sg_policy->policy; 295 unsigned long util = 0, max = 1; 296 unsigned int j; 297 298 for_each_cpu(j, policy->cpus) { 299 struct sugov_cpu *j_sg_cpu = &per_cpu(sugov_cpu, j); 300 unsigned long j_util, j_max; 301 s64 delta_ns; 302 303 /* 304 * If the CPU utilization was last updated before the previous 305 * frequency update and the time elapsed between the last update 306 * of the CPU utilization and the last frequency update is long 307 * enough, don't take the CPU into account as it probably is 308 * idle now (and clear iowait_boost for it). 309 */ 310 delta_ns = time - j_sg_cpu->last_update; 311 if (delta_ns > TICK_NSEC) { 312 j_sg_cpu->iowait_boost = 0; 313 j_sg_cpu->iowait_boost_pending = false; 314 continue; 315 } 316 if (j_sg_cpu->flags & SCHED_CPUFREQ_RT_DL) 317 return policy->cpuinfo.max_freq; 318 319 j_util = j_sg_cpu->util; 320 j_max = j_sg_cpu->max; 321 if (j_util * max > j_max * util) { 322 util = j_util; 323 max = j_max; 324 } 325 326 sugov_iowait_boost(j_sg_cpu, &util, &max); 327 } 328 329 return get_next_freq(sg_policy, util, max); 330 } 331 332 static void sugov_update_shared(struct update_util_data *hook, u64 time, 333 unsigned int flags) 334 { 335 struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util); 336 struct sugov_policy *sg_policy = sg_cpu->sg_policy; 337 unsigned long util, max; 338 unsigned int next_f; 339 340 sugov_get_util(&util, &max, sg_cpu->cpu); 341 342 raw_spin_lock(&sg_policy->update_lock); 343 344 sg_cpu->util = util; 345 sg_cpu->max = max; 346 sg_cpu->flags = flags; 347 348 sugov_set_iowait_boost(sg_cpu, time, flags); 349 sg_cpu->last_update = time; 350 351 if (sugov_should_update_freq(sg_policy, time)) { 352 if (flags & SCHED_CPUFREQ_RT_DL) 353 next_f = sg_policy->policy->cpuinfo.max_freq; 354 else 355 next_f = sugov_next_freq_shared(sg_cpu, time); 356 357 sugov_update_commit(sg_policy, time, next_f); 358 } 359 360 raw_spin_unlock(&sg_policy->update_lock); 361 } 362 363 static void sugov_work(struct kthread_work *work) 364 { 365 struct sugov_policy *sg_policy = container_of(work, struct sugov_policy, work); 366 367 mutex_lock(&sg_policy->work_lock); 368 __cpufreq_driver_target(sg_policy->policy, sg_policy->next_freq, 369 CPUFREQ_RELATION_L); 370 mutex_unlock(&sg_policy->work_lock); 371 372 sg_policy->work_in_progress = false; 373 } 374 375 static void sugov_irq_work(struct irq_work *irq_work) 376 { 377 struct sugov_policy *sg_policy; 378 379 sg_policy = container_of(irq_work, struct sugov_policy, irq_work); 380 381 /* 382 * For RT and deadline tasks, the schedutil governor shoots the 383 * frequency to maximum. Special care must be taken to ensure that this 384 * kthread doesn't result in the same behavior. 385 * 386 * This is (mostly) guaranteed by the work_in_progress flag. The flag is 387 * updated only at the end of the sugov_work() function and before that 388 * the schedutil governor rejects all other frequency scaling requests. 389 * 390 * There is a very rare case though, where the RT thread yields right 391 * after the work_in_progress flag is cleared. The effects of that are 392 * neglected for now. 393 */ 394 kthread_queue_work(&sg_policy->worker, &sg_policy->work); 395 } 396 397 /************************** sysfs interface ************************/ 398 399 static struct sugov_tunables *global_tunables; 400 static DEFINE_MUTEX(global_tunables_lock); 401 402 static inline struct sugov_tunables *to_sugov_tunables(struct gov_attr_set *attr_set) 403 { 404 return container_of(attr_set, struct sugov_tunables, attr_set); 405 } 406 407 static ssize_t rate_limit_us_show(struct gov_attr_set *attr_set, char *buf) 408 { 409 struct sugov_tunables *tunables = to_sugov_tunables(attr_set); 410 411 return sprintf(buf, "%u\n", tunables->rate_limit_us); 412 } 413 414 static ssize_t rate_limit_us_store(struct gov_attr_set *attr_set, const char *buf, 415 size_t count) 416 { 417 struct sugov_tunables *tunables = to_sugov_tunables(attr_set); 418 struct sugov_policy *sg_policy; 419 unsigned int rate_limit_us; 420 421 if (kstrtouint(buf, 10, &rate_limit_us)) 422 return -EINVAL; 423 424 tunables->rate_limit_us = rate_limit_us; 425 426 list_for_each_entry(sg_policy, &attr_set->policy_list, tunables_hook) 427 sg_policy->freq_update_delay_ns = rate_limit_us * NSEC_PER_USEC; 428 429 return count; 430 } 431 432 static struct governor_attr rate_limit_us = __ATTR_RW(rate_limit_us); 433 434 static struct attribute *sugov_attributes[] = { 435 &rate_limit_us.attr, 436 NULL 437 }; 438 439 static struct kobj_type sugov_tunables_ktype = { 440 .default_attrs = sugov_attributes, 441 .sysfs_ops = &governor_sysfs_ops, 442 }; 443 444 /********************** cpufreq governor interface *********************/ 445 446 static struct cpufreq_governor schedutil_gov; 447 448 static struct sugov_policy *sugov_policy_alloc(struct cpufreq_policy *policy) 449 { 450 struct sugov_policy *sg_policy; 451 452 sg_policy = kzalloc(sizeof(*sg_policy), GFP_KERNEL); 453 if (!sg_policy) 454 return NULL; 455 456 sg_policy->policy = policy; 457 raw_spin_lock_init(&sg_policy->update_lock); 458 return sg_policy; 459 } 460 461 static void sugov_policy_free(struct sugov_policy *sg_policy) 462 { 463 kfree(sg_policy); 464 } 465 466 static int sugov_kthread_create(struct sugov_policy *sg_policy) 467 { 468 struct task_struct *thread; 469 struct sched_param param = { .sched_priority = MAX_USER_RT_PRIO / 2 }; 470 struct cpufreq_policy *policy = sg_policy->policy; 471 int ret; 472 473 /* kthread only required for slow path */ 474 if (policy->fast_switch_enabled) 475 return 0; 476 477 kthread_init_work(&sg_policy->work, sugov_work); 478 kthread_init_worker(&sg_policy->worker); 479 thread = kthread_create(kthread_worker_fn, &sg_policy->worker, 480 "sugov:%d", 481 cpumask_first(policy->related_cpus)); 482 if (IS_ERR(thread)) { 483 pr_err("failed to create sugov thread: %ld\n", PTR_ERR(thread)); 484 return PTR_ERR(thread); 485 } 486 487 ret = sched_setscheduler_nocheck(thread, SCHED_FIFO, ¶m); 488 if (ret) { 489 kthread_stop(thread); 490 pr_warn("%s: failed to set SCHED_FIFO\n", __func__); 491 return ret; 492 } 493 494 sg_policy->thread = thread; 495 496 /* Kthread is bound to all CPUs by default */ 497 if (!policy->dvfs_possible_from_any_cpu) 498 kthread_bind_mask(thread, policy->related_cpus); 499 500 init_irq_work(&sg_policy->irq_work, sugov_irq_work); 501 mutex_init(&sg_policy->work_lock); 502 503 wake_up_process(thread); 504 505 return 0; 506 } 507 508 static void sugov_kthread_stop(struct sugov_policy *sg_policy) 509 { 510 /* kthread only required for slow path */ 511 if (sg_policy->policy->fast_switch_enabled) 512 return; 513 514 kthread_flush_worker(&sg_policy->worker); 515 kthread_stop(sg_policy->thread); 516 mutex_destroy(&sg_policy->work_lock); 517 } 518 519 static struct sugov_tunables *sugov_tunables_alloc(struct sugov_policy *sg_policy) 520 { 521 struct sugov_tunables *tunables; 522 523 tunables = kzalloc(sizeof(*tunables), GFP_KERNEL); 524 if (tunables) { 525 gov_attr_set_init(&tunables->attr_set, &sg_policy->tunables_hook); 526 if (!have_governor_per_policy()) 527 global_tunables = tunables; 528 } 529 return tunables; 530 } 531 532 static void sugov_tunables_free(struct sugov_tunables *tunables) 533 { 534 if (!have_governor_per_policy()) 535 global_tunables = NULL; 536 537 kfree(tunables); 538 } 539 540 static int sugov_init(struct cpufreq_policy *policy) 541 { 542 struct sugov_policy *sg_policy; 543 struct sugov_tunables *tunables; 544 int ret = 0; 545 546 /* State should be equivalent to EXIT */ 547 if (policy->governor_data) 548 return -EBUSY; 549 550 cpufreq_enable_fast_switch(policy); 551 552 sg_policy = sugov_policy_alloc(policy); 553 if (!sg_policy) { 554 ret = -ENOMEM; 555 goto disable_fast_switch; 556 } 557 558 ret = sugov_kthread_create(sg_policy); 559 if (ret) 560 goto free_sg_policy; 561 562 mutex_lock(&global_tunables_lock); 563 564 if (global_tunables) { 565 if (WARN_ON(have_governor_per_policy())) { 566 ret = -EINVAL; 567 goto stop_kthread; 568 } 569 policy->governor_data = sg_policy; 570 sg_policy->tunables = global_tunables; 571 572 gov_attr_set_get(&global_tunables->attr_set, &sg_policy->tunables_hook); 573 goto out; 574 } 575 576 tunables = sugov_tunables_alloc(sg_policy); 577 if (!tunables) { 578 ret = -ENOMEM; 579 goto stop_kthread; 580 } 581 582 tunables->rate_limit_us = cpufreq_policy_transition_delay_us(policy); 583 584 policy->governor_data = sg_policy; 585 sg_policy->tunables = tunables; 586 587 ret = kobject_init_and_add(&tunables->attr_set.kobj, &sugov_tunables_ktype, 588 get_governor_parent_kobj(policy), "%s", 589 schedutil_gov.name); 590 if (ret) 591 goto fail; 592 593 out: 594 mutex_unlock(&global_tunables_lock); 595 return 0; 596 597 fail: 598 policy->governor_data = NULL; 599 sugov_tunables_free(tunables); 600 601 stop_kthread: 602 sugov_kthread_stop(sg_policy); 603 604 free_sg_policy: 605 mutex_unlock(&global_tunables_lock); 606 607 sugov_policy_free(sg_policy); 608 609 disable_fast_switch: 610 cpufreq_disable_fast_switch(policy); 611 612 pr_err("initialization failed (error %d)\n", ret); 613 return ret; 614 } 615 616 static void sugov_exit(struct cpufreq_policy *policy) 617 { 618 struct sugov_policy *sg_policy = policy->governor_data; 619 struct sugov_tunables *tunables = sg_policy->tunables; 620 unsigned int count; 621 622 mutex_lock(&global_tunables_lock); 623 624 count = gov_attr_set_put(&tunables->attr_set, &sg_policy->tunables_hook); 625 policy->governor_data = NULL; 626 if (!count) 627 sugov_tunables_free(tunables); 628 629 mutex_unlock(&global_tunables_lock); 630 631 sugov_kthread_stop(sg_policy); 632 sugov_policy_free(sg_policy); 633 cpufreq_disable_fast_switch(policy); 634 } 635 636 static int sugov_start(struct cpufreq_policy *policy) 637 { 638 struct sugov_policy *sg_policy = policy->governor_data; 639 unsigned int cpu; 640 641 sg_policy->freq_update_delay_ns = sg_policy->tunables->rate_limit_us * NSEC_PER_USEC; 642 sg_policy->last_freq_update_time = 0; 643 sg_policy->next_freq = UINT_MAX; 644 sg_policy->work_in_progress = false; 645 sg_policy->need_freq_update = false; 646 sg_policy->cached_raw_freq = 0; 647 648 for_each_cpu(cpu, policy->cpus) { 649 struct sugov_cpu *sg_cpu = &per_cpu(sugov_cpu, cpu); 650 651 memset(sg_cpu, 0, sizeof(*sg_cpu)); 652 sg_cpu->sg_policy = sg_policy; 653 sg_cpu->flags = SCHED_CPUFREQ_RT; 654 sg_cpu->iowait_boost_max = policy->cpuinfo.max_freq; 655 } 656 657 for_each_cpu(cpu, policy->cpus) { 658 struct sugov_cpu *sg_cpu = &per_cpu(sugov_cpu, cpu); 659 660 cpufreq_add_update_util_hook(cpu, &sg_cpu->update_util, 661 policy_is_shared(policy) ? 662 sugov_update_shared : 663 sugov_update_single); 664 } 665 return 0; 666 } 667 668 static void sugov_stop(struct cpufreq_policy *policy) 669 { 670 struct sugov_policy *sg_policy = policy->governor_data; 671 unsigned int cpu; 672 673 for_each_cpu(cpu, policy->cpus) 674 cpufreq_remove_update_util_hook(cpu); 675 676 synchronize_sched(); 677 678 if (!policy->fast_switch_enabled) { 679 irq_work_sync(&sg_policy->irq_work); 680 kthread_cancel_work_sync(&sg_policy->work); 681 } 682 } 683 684 static void sugov_limits(struct cpufreq_policy *policy) 685 { 686 struct sugov_policy *sg_policy = policy->governor_data; 687 688 if (!policy->fast_switch_enabled) { 689 mutex_lock(&sg_policy->work_lock); 690 cpufreq_policy_apply_limits(policy); 691 mutex_unlock(&sg_policy->work_lock); 692 } 693 694 sg_policy->need_freq_update = true; 695 } 696 697 static struct cpufreq_governor schedutil_gov = { 698 .name = "schedutil", 699 .owner = THIS_MODULE, 700 .dynamic_switching = true, 701 .init = sugov_init, 702 .exit = sugov_exit, 703 .start = sugov_start, 704 .stop = sugov_stop, 705 .limits = sugov_limits, 706 }; 707 708 #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_SCHEDUTIL 709 struct cpufreq_governor *cpufreq_default_governor(void) 710 { 711 return &schedutil_gov; 712 } 713 #endif 714 715 static int __init sugov_register(void) 716 { 717 int cpu; 718 719 for_each_possible_cpu(cpu) 720 per_cpu(sugov_cpu, cpu).cpu = cpu; 721 722 return cpufreq_register_governor(&schedutil_gov); 723 } 724 fs_initcall(sugov_register); 725