core.c revision 5cd038f53ed9ec7a17ab7d536a727363080f4210
1/* 2 * kernel/sched/core.c 3 * 4 * Kernel scheduler and related syscalls 5 * 6 * Copyright (C) 1991-2002 Linus Torvalds 7 * 8 * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and 9 * make semaphores SMP safe 10 * 1998-11-19 Implemented schedule_timeout() and related stuff 11 * by Andrea Arcangeli 12 * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar: 13 * hybrid priority-list and round-robin design with 14 * an array-switch method of distributing timeslices 15 * and per-CPU runqueues. Cleanups and useful suggestions 16 * by Davide Libenzi, preemptible kernel bits by Robert Love. 17 * 2003-09-03 Interactivity tuning by Con Kolivas. 18 * 2004-04-02 Scheduler domains code by Nick Piggin 19 * 2007-04-15 Work begun on replacing all interactivity tuning with a 20 * fair scheduling design by Con Kolivas. 21 * 2007-05-05 Load balancing (smp-nice) and other improvements 22 * by Peter Williams 23 * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith 24 * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri 25 * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins, 26 * Thomas Gleixner, Mike Kravetz 27 */ 28 29#include <linux/mm.h> 30#include <linux/module.h> 31#include <linux/nmi.h> 32#include <linux/init.h> 33#include <linux/uaccess.h> 34#include <linux/highmem.h> 35#include <asm/mmu_context.h> 36#include <linux/interrupt.h> 37#include <linux/capability.h> 38#include <linux/completion.h> 39#include <linux/kernel_stat.h> 40#include <linux/debug_locks.h> 41#include <linux/perf_event.h> 42#include <linux/security.h> 43#include <linux/notifier.h> 44#include <linux/profile.h> 45#include <linux/freezer.h> 46#include <linux/vmalloc.h> 47#include <linux/blkdev.h> 48#include <linux/delay.h> 49#include <linux/pid_namespace.h> 50#include <linux/smp.h> 51#include <linux/threads.h> 52#include <linux/timer.h> 53#include <linux/rcupdate.h> 54#include <linux/cpu.h> 55#include <linux/cpuset.h> 56#include <linux/percpu.h> 57#include <linux/proc_fs.h> 58#include <linux/seq_file.h> 59#include <linux/sysctl.h> 60#include <linux/syscalls.h> 61#include <linux/times.h> 62#include <linux/tsacct_kern.h> 63#include <linux/kprobes.h> 64#include <linux/delayacct.h> 65#include <linux/unistd.h> 66#include <linux/pagemap.h> 67#include <linux/hrtimer.h> 68#include <linux/tick.h> 69#include <linux/debugfs.h> 70#include <linux/ctype.h> 71#include <linux/ftrace.h> 72#include <linux/slab.h> 73#include <linux/init_task.h> 74#include <linux/binfmts.h> 75#include <linux/context_tracking.h> 76#include <linux/compiler.h> 77 78#include <asm/switch_to.h> 79#include <asm/tlb.h> 80#include <asm/irq_regs.h> 81#include <asm/mutex.h> 82#ifdef CONFIG_PARAVIRT 83#include <asm/paravirt.h> 84#endif 85 86#include "sched.h" 87#include "../workqueue_internal.h" 88#include "../smpboot.h" 89 90#define CREATE_TRACE_POINTS 91#include <trace/events/sched.h> 92 93#ifdef smp_mb__before_atomic 94void __smp_mb__before_atomic(void) 95{ 96 smp_mb__before_atomic(); 97} 98EXPORT_SYMBOL(__smp_mb__before_atomic); 99#endif 100 101#ifdef smp_mb__after_atomic 102void __smp_mb__after_atomic(void) 103{ 104 smp_mb__after_atomic(); 105} 106EXPORT_SYMBOL(__smp_mb__after_atomic); 107#endif 108 109void start_bandwidth_timer(struct hrtimer *period_timer, ktime_t period) 110{ 111 unsigned long delta; 112 ktime_t soft, hard, now; 113 114 for (;;) { 115 if (hrtimer_active(period_timer)) 116 break; 117 118 now = hrtimer_cb_get_time(period_timer); 119 hrtimer_forward(period_timer, now, period); 120 121 soft = hrtimer_get_softexpires(period_timer); 122 hard = hrtimer_get_expires(period_timer); 123 delta = ktime_to_ns(ktime_sub(hard, soft)); 124 __hrtimer_start_range_ns(period_timer, soft, delta, 125 HRTIMER_MODE_ABS_PINNED, 0); 126 } 127} 128 129DEFINE_MUTEX(sched_domains_mutex); 130DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); 131 132static void update_rq_clock_task(struct rq *rq, s64 delta); 133 134void update_rq_clock(struct rq *rq) 135{ 136 s64 delta; 137 138 if (rq->skip_clock_update > 0) 139 return; 140 141 delta = sched_clock_cpu(cpu_of(rq)) - rq->clock; 142 if (delta < 0) 143 return; 144 rq->clock += delta; 145 update_rq_clock_task(rq, delta); 146} 147 148/* 149 * Debugging: various feature bits 150 */ 151 152#define SCHED_FEAT(name, enabled) \ 153 (1UL << __SCHED_FEAT_##name) * enabled | 154 155const_debug unsigned int sysctl_sched_features = 156#include "features.h" 157 0; 158 159#undef SCHED_FEAT 160 161#ifdef CONFIG_SCHED_DEBUG 162#define SCHED_FEAT(name, enabled) \ 163 #name , 164 165static const char * const sched_feat_names[] = { 166#include "features.h" 167}; 168 169#undef SCHED_FEAT 170 171static int sched_feat_show(struct seq_file *m, void *v) 172{ 173 int i; 174 175 for (i = 0; i < __SCHED_FEAT_NR; i++) { 176 if (!(sysctl_sched_features & (1UL << i))) 177 seq_puts(m, "NO_"); 178 seq_printf(m, "%s ", sched_feat_names[i]); 179 } 180 seq_puts(m, "\n"); 181 182 return 0; 183} 184 185#ifdef HAVE_JUMP_LABEL 186 187#define jump_label_key__true STATIC_KEY_INIT_TRUE 188#define jump_label_key__false STATIC_KEY_INIT_FALSE 189 190#define SCHED_FEAT(name, enabled) \ 191 jump_label_key__##enabled , 192 193struct static_key sched_feat_keys[__SCHED_FEAT_NR] = { 194#include "features.h" 195}; 196 197#undef SCHED_FEAT 198 199static void sched_feat_disable(int i) 200{ 201 if (static_key_enabled(&sched_feat_keys[i])) 202 static_key_slow_dec(&sched_feat_keys[i]); 203} 204 205static void sched_feat_enable(int i) 206{ 207 if (!static_key_enabled(&sched_feat_keys[i])) 208 static_key_slow_inc(&sched_feat_keys[i]); 209} 210#else 211static void sched_feat_disable(int i) { }; 212static void sched_feat_enable(int i) { }; 213#endif /* HAVE_JUMP_LABEL */ 214 215static int sched_feat_set(char *cmp) 216{ 217 int i; 218 int neg = 0; 219 220 if (strncmp(cmp, "NO_", 3) == 0) { 221 neg = 1; 222 cmp += 3; 223 } 224 225 for (i = 0; i < __SCHED_FEAT_NR; i++) { 226 if (strcmp(cmp, sched_feat_names[i]) == 0) { 227 if (neg) { 228 sysctl_sched_features &= ~(1UL << i); 229 sched_feat_disable(i); 230 } else { 231 sysctl_sched_features |= (1UL << i); 232 sched_feat_enable(i); 233 } 234 break; 235 } 236 } 237 238 return i; 239} 240 241static ssize_t 242sched_feat_write(struct file *filp, const char __user *ubuf, 243 size_t cnt, loff_t *ppos) 244{ 245 char buf[64]; 246 char *cmp; 247 int i; 248 struct inode *inode; 249 250 if (cnt > 63) 251 cnt = 63; 252 253 if (copy_from_user(&buf, ubuf, cnt)) 254 return -EFAULT; 255 256 buf[cnt] = 0; 257 cmp = strstrip(buf); 258 259 /* Ensure the static_key remains in a consistent state */ 260 inode = file_inode(filp); 261 mutex_lock(&inode->i_mutex); 262 i = sched_feat_set(cmp); 263 mutex_unlock(&inode->i_mutex); 264 if (i == __SCHED_FEAT_NR) 265 return -EINVAL; 266 267 *ppos += cnt; 268 269 return cnt; 270} 271 272static int sched_feat_open(struct inode *inode, struct file *filp) 273{ 274 return single_open(filp, sched_feat_show, NULL); 275} 276 277static const struct file_operations sched_feat_fops = { 278 .open = sched_feat_open, 279 .write = sched_feat_write, 280 .read = seq_read, 281 .llseek = seq_lseek, 282 .release = single_release, 283}; 284 285static __init int sched_init_debug(void) 286{ 287 debugfs_create_file("sched_features", 0644, NULL, NULL, 288 &sched_feat_fops); 289 290 return 0; 291} 292late_initcall(sched_init_debug); 293#endif /* CONFIG_SCHED_DEBUG */ 294 295/* 296 * Number of tasks to iterate in a single balance run. 297 * Limited because this is done with IRQs disabled. 298 */ 299const_debug unsigned int sysctl_sched_nr_migrate = 32; 300 301/* 302 * period over which we average the RT time consumption, measured 303 * in ms. 304 * 305 * default: 1s 306 */ 307const_debug unsigned int sysctl_sched_time_avg = MSEC_PER_SEC; 308 309/* 310 * period over which we measure -rt task cpu usage in us. 311 * default: 1s 312 */ 313unsigned int sysctl_sched_rt_period = 1000000; 314 315__read_mostly int scheduler_running; 316 317/* 318 * part of the period that we allow rt tasks to run in us. 319 * default: 0.95s 320 */ 321int sysctl_sched_rt_runtime = 950000; 322 323/* 324 * __task_rq_lock - lock the rq @p resides on. 325 */ 326static inline struct rq *__task_rq_lock(struct task_struct *p) 327 __acquires(rq->lock) 328{ 329 struct rq *rq; 330 331 lockdep_assert_held(&p->pi_lock); 332 333 for (;;) { 334 rq = task_rq(p); 335 raw_spin_lock(&rq->lock); 336 if (likely(rq == task_rq(p) && !task_on_rq_migrating(p))) 337 return rq; 338 raw_spin_unlock(&rq->lock); 339 340 while (unlikely(task_on_rq_migrating(p))) 341 cpu_relax(); 342 } 343} 344 345/* 346 * task_rq_lock - lock p->pi_lock and lock the rq @p resides on. 347 */ 348static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags) 349 __acquires(p->pi_lock) 350 __acquires(rq->lock) 351{ 352 struct rq *rq; 353 354 for (;;) { 355 raw_spin_lock_irqsave(&p->pi_lock, *flags); 356 rq = task_rq(p); 357 raw_spin_lock(&rq->lock); 358 if (likely(rq == task_rq(p) && !task_on_rq_migrating(p))) 359 return rq; 360 raw_spin_unlock(&rq->lock); 361 raw_spin_unlock_irqrestore(&p->pi_lock, *flags); 362 363 while (unlikely(task_on_rq_migrating(p))) 364 cpu_relax(); 365 } 366} 367 368static void __task_rq_unlock(struct rq *rq) 369 __releases(rq->lock) 370{ 371 raw_spin_unlock(&rq->lock); 372} 373 374static inline void 375task_rq_unlock(struct rq *rq, struct task_struct *p, unsigned long *flags) 376 __releases(rq->lock) 377 __releases(p->pi_lock) 378{ 379 raw_spin_unlock(&rq->lock); 380 raw_spin_unlock_irqrestore(&p->pi_lock, *flags); 381} 382 383/* 384 * this_rq_lock - lock this runqueue and disable interrupts. 385 */ 386static struct rq *this_rq_lock(void) 387 __acquires(rq->lock) 388{ 389 struct rq *rq; 390 391 local_irq_disable(); 392 rq = this_rq(); 393 raw_spin_lock(&rq->lock); 394 395 return rq; 396} 397 398#ifdef CONFIG_SCHED_HRTICK 399/* 400 * Use HR-timers to deliver accurate preemption points. 401 */ 402 403static void hrtick_clear(struct rq *rq) 404{ 405 if (hrtimer_active(&rq->hrtick_timer)) 406 hrtimer_cancel(&rq->hrtick_timer); 407} 408 409/* 410 * High-resolution timer tick. 411 * Runs from hardirq context with interrupts disabled. 412 */ 413static enum hrtimer_restart hrtick(struct hrtimer *timer) 414{ 415 struct rq *rq = container_of(timer, struct rq, hrtick_timer); 416 417 WARN_ON_ONCE(cpu_of(rq) != smp_processor_id()); 418 419 raw_spin_lock(&rq->lock); 420 update_rq_clock(rq); 421 rq->curr->sched_class->task_tick(rq, rq->curr, 1); 422 raw_spin_unlock(&rq->lock); 423 424 return HRTIMER_NORESTART; 425} 426 427#ifdef CONFIG_SMP 428 429static int __hrtick_restart(struct rq *rq) 430{ 431 struct hrtimer *timer = &rq->hrtick_timer; 432 ktime_t time = hrtimer_get_softexpires(timer); 433 434 return __hrtimer_start_range_ns(timer, time, 0, HRTIMER_MODE_ABS_PINNED, 0); 435} 436 437/* 438 * called from hardirq (IPI) context 439 */ 440static void __hrtick_start(void *arg) 441{ 442 struct rq *rq = arg; 443 444 raw_spin_lock(&rq->lock); 445 __hrtick_restart(rq); 446 rq->hrtick_csd_pending = 0; 447 raw_spin_unlock(&rq->lock); 448} 449 450/* 451 * Called to set the hrtick timer state. 452 * 453 * called with rq->lock held and irqs disabled 454 */ 455void hrtick_start(struct rq *rq, u64 delay) 456{ 457 struct hrtimer *timer = &rq->hrtick_timer; 458 ktime_t time; 459 s64 delta; 460 461 /* 462 * Don't schedule slices shorter than 10000ns, that just 463 * doesn't make sense and can cause timer DoS. 464 */ 465 delta = max_t(s64, delay, 10000LL); 466 time = ktime_add_ns(timer->base->get_time(), delta); 467 468 hrtimer_set_expires(timer, time); 469 470 if (rq == this_rq()) { 471 __hrtick_restart(rq); 472 } else if (!rq->hrtick_csd_pending) { 473 smp_call_function_single_async(cpu_of(rq), &rq->hrtick_csd); 474 rq->hrtick_csd_pending = 1; 475 } 476} 477 478static int 479hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu) 480{ 481 int cpu = (int)(long)hcpu; 482 483 switch (action) { 484 case CPU_UP_CANCELED: 485 case CPU_UP_CANCELED_FROZEN: 486 case CPU_DOWN_PREPARE: 487 case CPU_DOWN_PREPARE_FROZEN: 488 case CPU_DEAD: 489 case CPU_DEAD_FROZEN: 490 hrtick_clear(cpu_rq(cpu)); 491 return NOTIFY_OK; 492 } 493 494 return NOTIFY_DONE; 495} 496 497static __init void init_hrtick(void) 498{ 499 hotcpu_notifier(hotplug_hrtick, 0); 500} 501#else 502/* 503 * Called to set the hrtick timer state. 504 * 505 * called with rq->lock held and irqs disabled 506 */ 507void hrtick_start(struct rq *rq, u64 delay) 508{ 509 __hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0, 510 HRTIMER_MODE_REL_PINNED, 0); 511} 512 513static inline void init_hrtick(void) 514{ 515} 516#endif /* CONFIG_SMP */ 517 518static void init_rq_hrtick(struct rq *rq) 519{ 520#ifdef CONFIG_SMP 521 rq->hrtick_csd_pending = 0; 522 523 rq->hrtick_csd.flags = 0; 524 rq->hrtick_csd.func = __hrtick_start; 525 rq->hrtick_csd.info = rq; 526#endif 527 528 hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 529 rq->hrtick_timer.function = hrtick; 530} 531#else /* CONFIG_SCHED_HRTICK */ 532static inline void hrtick_clear(struct rq *rq) 533{ 534} 535 536static inline void init_rq_hrtick(struct rq *rq) 537{ 538} 539 540static inline void init_hrtick(void) 541{ 542} 543#endif /* CONFIG_SCHED_HRTICK */ 544 545/* 546 * cmpxchg based fetch_or, macro so it works for different integer types 547 */ 548#define fetch_or(ptr, val) \ 549({ typeof(*(ptr)) __old, __val = *(ptr); \ 550 for (;;) { \ 551 __old = cmpxchg((ptr), __val, __val | (val)); \ 552 if (__old == __val) \ 553 break; \ 554 __val = __old; \ 555 } \ 556 __old; \ 557}) 558 559#if defined(CONFIG_SMP) && defined(TIF_POLLING_NRFLAG) 560/* 561 * Atomically set TIF_NEED_RESCHED and test for TIF_POLLING_NRFLAG, 562 * this avoids any races wrt polling state changes and thereby avoids 563 * spurious IPIs. 564 */ 565static bool set_nr_and_not_polling(struct task_struct *p) 566{ 567 struct thread_info *ti = task_thread_info(p); 568 return !(fetch_or(&ti->flags, _TIF_NEED_RESCHED) & _TIF_POLLING_NRFLAG); 569} 570 571/* 572 * Atomically set TIF_NEED_RESCHED if TIF_POLLING_NRFLAG is set. 573 * 574 * If this returns true, then the idle task promises to call 575 * sched_ttwu_pending() and reschedule soon. 576 */ 577static bool set_nr_if_polling(struct task_struct *p) 578{ 579 struct thread_info *ti = task_thread_info(p); 580 typeof(ti->flags) old, val = ACCESS_ONCE(ti->flags); 581 582 for (;;) { 583 if (!(val & _TIF_POLLING_NRFLAG)) 584 return false; 585 if (val & _TIF_NEED_RESCHED) 586 return true; 587 old = cmpxchg(&ti->flags, val, val | _TIF_NEED_RESCHED); 588 if (old == val) 589 break; 590 val = old; 591 } 592 return true; 593} 594 595#else 596static bool set_nr_and_not_polling(struct task_struct *p) 597{ 598 set_tsk_need_resched(p); 599 return true; 600} 601 602#ifdef CONFIG_SMP 603static bool set_nr_if_polling(struct task_struct *p) 604{ 605 return false; 606} 607#endif 608#endif 609 610/* 611 * resched_curr - mark rq's current task 'to be rescheduled now'. 612 * 613 * On UP this means the setting of the need_resched flag, on SMP it 614 * might also involve a cross-CPU call to trigger the scheduler on 615 * the target CPU. 616 */ 617void resched_curr(struct rq *rq) 618{ 619 struct task_struct *curr = rq->curr; 620 int cpu; 621 622 lockdep_assert_held(&rq->lock); 623 624 if (test_tsk_need_resched(curr)) 625 return; 626 627 cpu = cpu_of(rq); 628 629 if (cpu == smp_processor_id()) { 630 set_tsk_need_resched(curr); 631 set_preempt_need_resched(); 632 return; 633 } 634 635 if (set_nr_and_not_polling(curr)) 636 smp_send_reschedule(cpu); 637 else 638 trace_sched_wake_idle_without_ipi(cpu); 639} 640 641void resched_cpu(int cpu) 642{ 643 struct rq *rq = cpu_rq(cpu); 644 unsigned long flags; 645 646 if (!raw_spin_trylock_irqsave(&rq->lock, flags)) 647 return; 648 resched_curr(rq); 649 raw_spin_unlock_irqrestore(&rq->lock, flags); 650} 651 652#ifdef CONFIG_SMP 653#ifdef CONFIG_NO_HZ_COMMON 654/* 655 * In the semi idle case, use the nearest busy cpu for migrating timers 656 * from an idle cpu. This is good for power-savings. 657 * 658 * We don't do similar optimization for completely idle system, as 659 * selecting an idle cpu will add more delays to the timers than intended 660 * (as that cpu's timer base may not be uptodate wrt jiffies etc). 661 */ 662int get_nohz_timer_target(int pinned) 663{ 664 int cpu = smp_processor_id(); 665 int i; 666 struct sched_domain *sd; 667 668 if (pinned || !get_sysctl_timer_migration() || !idle_cpu(cpu)) 669 return cpu; 670 671 rcu_read_lock(); 672 for_each_domain(cpu, sd) { 673 for_each_cpu(i, sched_domain_span(sd)) { 674 if (!idle_cpu(i)) { 675 cpu = i; 676 goto unlock; 677 } 678 } 679 } 680unlock: 681 rcu_read_unlock(); 682 return cpu; 683} 684/* 685 * When add_timer_on() enqueues a timer into the timer wheel of an 686 * idle CPU then this timer might expire before the next timer event 687 * which is scheduled to wake up that CPU. In case of a completely 688 * idle system the next event might even be infinite time into the 689 * future. wake_up_idle_cpu() ensures that the CPU is woken up and 690 * leaves the inner idle loop so the newly added timer is taken into 691 * account when the CPU goes back to idle and evaluates the timer 692 * wheel for the next timer event. 693 */ 694static void wake_up_idle_cpu(int cpu) 695{ 696 struct rq *rq = cpu_rq(cpu); 697 698 if (cpu == smp_processor_id()) 699 return; 700 701 if (set_nr_and_not_polling(rq->idle)) 702 smp_send_reschedule(cpu); 703 else 704 trace_sched_wake_idle_without_ipi(cpu); 705} 706 707static bool wake_up_full_nohz_cpu(int cpu) 708{ 709 /* 710 * We just need the target to call irq_exit() and re-evaluate 711 * the next tick. The nohz full kick at least implies that. 712 * If needed we can still optimize that later with an 713 * empty IRQ. 714 */ 715 if (tick_nohz_full_cpu(cpu)) { 716 if (cpu != smp_processor_id() || 717 tick_nohz_tick_stopped()) 718 tick_nohz_full_kick_cpu(cpu); 719 return true; 720 } 721 722 return false; 723} 724 725void wake_up_nohz_cpu(int cpu) 726{ 727 if (!wake_up_full_nohz_cpu(cpu)) 728 wake_up_idle_cpu(cpu); 729} 730 731static inline bool got_nohz_idle_kick(void) 732{ 733 int cpu = smp_processor_id(); 734 735 if (!test_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu))) 736 return false; 737 738 if (idle_cpu(cpu) && !need_resched()) 739 return true; 740 741 /* 742 * We can't run Idle Load Balance on this CPU for this time so we 743 * cancel it and clear NOHZ_BALANCE_KICK 744 */ 745 clear_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu)); 746 return false; 747} 748 749#else /* CONFIG_NO_HZ_COMMON */ 750 751static inline bool got_nohz_idle_kick(void) 752{ 753 return false; 754} 755 756#endif /* CONFIG_NO_HZ_COMMON */ 757 758#ifdef CONFIG_NO_HZ_FULL 759bool sched_can_stop_tick(void) 760{ 761 /* 762 * More than one running task need preemption. 763 * nr_running update is assumed to be visible 764 * after IPI is sent from wakers. 765 */ 766 if (this_rq()->nr_running > 1) 767 return false; 768 769 return true; 770} 771#endif /* CONFIG_NO_HZ_FULL */ 772 773void sched_avg_update(struct rq *rq) 774{ 775 s64 period = sched_avg_period(); 776 777 while ((s64)(rq_clock(rq) - rq->age_stamp) > period) { 778 /* 779 * Inline assembly required to prevent the compiler 780 * optimising this loop into a divmod call. 781 * See __iter_div_u64_rem() for another example of this. 782 */ 783 asm("" : "+rm" (rq->age_stamp)); 784 rq->age_stamp += period; 785 rq->rt_avg /= 2; 786 } 787} 788 789#endif /* CONFIG_SMP */ 790 791#if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \ 792 (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH))) 793/* 794 * Iterate task_group tree rooted at *from, calling @down when first entering a 795 * node and @up when leaving it for the final time. 796 * 797 * Caller must hold rcu_lock or sufficient equivalent. 798 */ 799int walk_tg_tree_from(struct task_group *from, 800 tg_visitor down, tg_visitor up, void *data) 801{ 802 struct task_group *parent, *child; 803 int ret; 804 805 parent = from; 806 807down: 808 ret = (*down)(parent, data); 809 if (ret) 810 goto out; 811 list_for_each_entry_rcu(child, &parent->children, siblings) { 812 parent = child; 813 goto down; 814 815up: 816 continue; 817 } 818 ret = (*up)(parent, data); 819 if (ret || parent == from) 820 goto out; 821 822 child = parent; 823 parent = parent->parent; 824 if (parent) 825 goto up; 826out: 827 return ret; 828} 829 830int tg_nop(struct task_group *tg, void *data) 831{ 832 return 0; 833} 834#endif 835 836static void set_load_weight(struct task_struct *p) 837{ 838 int prio = p->static_prio - MAX_RT_PRIO; 839 struct load_weight *load = &p->se.load; 840 841 /* 842 * SCHED_IDLE tasks get minimal weight: 843 */ 844 if (p->policy == SCHED_IDLE) { 845 load->weight = scale_load(WEIGHT_IDLEPRIO); 846 load->inv_weight = WMULT_IDLEPRIO; 847 return; 848 } 849 850 load->weight = scale_load(prio_to_weight[prio]); 851 load->inv_weight = prio_to_wmult[prio]; 852} 853 854static void enqueue_task(struct rq *rq, struct task_struct *p, int flags) 855{ 856 update_rq_clock(rq); 857 sched_info_queued(rq, p); 858 p->sched_class->enqueue_task(rq, p, flags); 859} 860 861static void dequeue_task(struct rq *rq, struct task_struct *p, int flags) 862{ 863 update_rq_clock(rq); 864 sched_info_dequeued(rq, p); 865 p->sched_class->dequeue_task(rq, p, flags); 866} 867 868void activate_task(struct rq *rq, struct task_struct *p, int flags) 869{ 870 if (task_contributes_to_load(p)) 871 rq->nr_uninterruptible--; 872 873 enqueue_task(rq, p, flags); 874} 875 876void deactivate_task(struct rq *rq, struct task_struct *p, int flags) 877{ 878 if (task_contributes_to_load(p)) 879 rq->nr_uninterruptible++; 880 881 dequeue_task(rq, p, flags); 882} 883 884static void update_rq_clock_task(struct rq *rq, s64 delta) 885{ 886/* 887 * In theory, the compile should just see 0 here, and optimize out the call 888 * to sched_rt_avg_update. But I don't trust it... 889 */ 890#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) 891 s64 steal = 0, irq_delta = 0; 892#endif 893#ifdef CONFIG_IRQ_TIME_ACCOUNTING 894 irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time; 895 896 /* 897 * Since irq_time is only updated on {soft,}irq_exit, we might run into 898 * this case when a previous update_rq_clock() happened inside a 899 * {soft,}irq region. 900 * 901 * When this happens, we stop ->clock_task and only update the 902 * prev_irq_time stamp to account for the part that fit, so that a next 903 * update will consume the rest. This ensures ->clock_task is 904 * monotonic. 905 * 906 * It does however cause some slight miss-attribution of {soft,}irq 907 * time, a more accurate solution would be to update the irq_time using 908 * the current rq->clock timestamp, except that would require using 909 * atomic ops. 910 */ 911 if (irq_delta > delta) 912 irq_delta = delta; 913 914 rq->prev_irq_time += irq_delta; 915 delta -= irq_delta; 916#endif 917#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING 918 if (static_key_false((¶virt_steal_rq_enabled))) { 919 steal = paravirt_steal_clock(cpu_of(rq)); 920 steal -= rq->prev_steal_time_rq; 921 922 if (unlikely(steal > delta)) 923 steal = delta; 924 925 rq->prev_steal_time_rq += steal; 926 delta -= steal; 927 } 928#endif 929 930 rq->clock_task += delta; 931 932#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) 933 if ((irq_delta + steal) && sched_feat(NONTASK_CAPACITY)) 934 sched_rt_avg_update(rq, irq_delta + steal); 935#endif 936} 937 938void sched_set_stop_task(int cpu, struct task_struct *stop) 939{ 940 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 }; 941 struct task_struct *old_stop = cpu_rq(cpu)->stop; 942 943 if (stop) { 944 /* 945 * Make it appear like a SCHED_FIFO task, its something 946 * userspace knows about and won't get confused about. 947 * 948 * Also, it will make PI more or less work without too 949 * much confusion -- but then, stop work should not 950 * rely on PI working anyway. 951 */ 952 sched_setscheduler_nocheck(stop, SCHED_FIFO, ¶m); 953 954 stop->sched_class = &stop_sched_class; 955 } 956 957 cpu_rq(cpu)->stop = stop; 958 959 if (old_stop) { 960 /* 961 * Reset it back to a normal scheduling class so that 962 * it can die in pieces. 963 */ 964 old_stop->sched_class = &rt_sched_class; 965 } 966} 967 968/* 969 * __normal_prio - return the priority that is based on the static prio 970 */ 971static inline int __normal_prio(struct task_struct *p) 972{ 973 return p->static_prio; 974} 975 976/* 977 * Calculate the expected normal priority: i.e. priority 978 * without taking RT-inheritance into account. Might be 979 * boosted by interactivity modifiers. Changes upon fork, 980 * setprio syscalls, and whenever the interactivity 981 * estimator recalculates. 982 */ 983static inline int normal_prio(struct task_struct *p) 984{ 985 int prio; 986 987 if (task_has_dl_policy(p)) 988 prio = MAX_DL_PRIO-1; 989 else if (task_has_rt_policy(p)) 990 prio = MAX_RT_PRIO-1 - p->rt_priority; 991 else 992 prio = __normal_prio(p); 993 return prio; 994} 995 996/* 997 * Calculate the current priority, i.e. the priority 998 * taken into account by the scheduler. This value might 999 * be boosted by RT tasks, or might be boosted by 1000 * interactivity modifiers. Will be RT if the task got 1001 * RT-boosted. If not then it returns p->normal_prio. 1002 */ 1003static int effective_prio(struct task_struct *p) 1004{ 1005 p->normal_prio = normal_prio(p); 1006 /* 1007 * If we are RT tasks or we were boosted to RT priority, 1008 * keep the priority unchanged. Otherwise, update priority 1009 * to the normal priority: 1010 */ 1011 if (!rt_prio(p->prio)) 1012 return p->normal_prio; 1013 return p->prio; 1014} 1015 1016/** 1017 * task_curr - is this task currently executing on a CPU? 1018 * @p: the task in question. 1019 * 1020 * Return: 1 if the task is currently executing. 0 otherwise. 1021 */ 1022inline int task_curr(const struct task_struct *p) 1023{ 1024 return cpu_curr(task_cpu(p)) == p; 1025} 1026 1027static inline void check_class_changed(struct rq *rq, struct task_struct *p, 1028 const struct sched_class *prev_class, 1029 int oldprio) 1030{ 1031 if (prev_class != p->sched_class) { 1032 if (prev_class->switched_from) 1033 prev_class->switched_from(rq, p); 1034 p->sched_class->switched_to(rq, p); 1035 } else if (oldprio != p->prio || dl_task(p)) 1036 p->sched_class->prio_changed(rq, p, oldprio); 1037} 1038 1039void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags) 1040{ 1041 const struct sched_class *class; 1042 1043 if (p->sched_class == rq->curr->sched_class) { 1044 rq->curr->sched_class->check_preempt_curr(rq, p, flags); 1045 } else { 1046 for_each_class(class) { 1047 if (class == rq->curr->sched_class) 1048 break; 1049 if (class == p->sched_class) { 1050 resched_curr(rq); 1051 break; 1052 } 1053 } 1054 } 1055 1056 /* 1057 * A queue event has occurred, and we're going to schedule. In 1058 * this case, we can save a useless back to back clock update. 1059 */ 1060 if (task_on_rq_queued(rq->curr) && test_tsk_need_resched(rq->curr)) 1061 rq->skip_clock_update = 1; 1062} 1063 1064#ifdef CONFIG_SMP 1065void set_task_cpu(struct task_struct *p, unsigned int new_cpu) 1066{ 1067#ifdef CONFIG_SCHED_DEBUG 1068 /* 1069 * We should never call set_task_cpu() on a blocked task, 1070 * ttwu() will sort out the placement. 1071 */ 1072 WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING && 1073 !(task_preempt_count(p) & PREEMPT_ACTIVE)); 1074 1075#ifdef CONFIG_LOCKDEP 1076 /* 1077 * The caller should hold either p->pi_lock or rq->lock, when changing 1078 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks. 1079 * 1080 * sched_move_task() holds both and thus holding either pins the cgroup, 1081 * see task_group(). 1082 * 1083 * Furthermore, all task_rq users should acquire both locks, see 1084 * task_rq_lock(). 1085 */ 1086 WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) || 1087 lockdep_is_held(&task_rq(p)->lock))); 1088#endif 1089#endif 1090 1091 trace_sched_migrate_task(p, new_cpu); 1092 1093 if (task_cpu(p) != new_cpu) { 1094 if (p->sched_class->migrate_task_rq) 1095 p->sched_class->migrate_task_rq(p, new_cpu); 1096 p->se.nr_migrations++; 1097 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, 1, NULL, 0); 1098 } 1099 1100 __set_task_cpu(p, new_cpu); 1101} 1102 1103static void __migrate_swap_task(struct task_struct *p, int cpu) 1104{ 1105 if (task_on_rq_queued(p)) { 1106 struct rq *src_rq, *dst_rq; 1107 1108 src_rq = task_rq(p); 1109 dst_rq = cpu_rq(cpu); 1110 1111 deactivate_task(src_rq, p, 0); 1112 set_task_cpu(p, cpu); 1113 activate_task(dst_rq, p, 0); 1114 check_preempt_curr(dst_rq, p, 0); 1115 } else { 1116 /* 1117 * Task isn't running anymore; make it appear like we migrated 1118 * it before it went to sleep. This means on wakeup we make the 1119 * previous cpu our targer instead of where it really is. 1120 */ 1121 p->wake_cpu = cpu; 1122 } 1123} 1124 1125struct migration_swap_arg { 1126 struct task_struct *src_task, *dst_task; 1127 int src_cpu, dst_cpu; 1128}; 1129 1130static int migrate_swap_stop(void *data) 1131{ 1132 struct migration_swap_arg *arg = data; 1133 struct rq *src_rq, *dst_rq; 1134 int ret = -EAGAIN; 1135 1136 src_rq = cpu_rq(arg->src_cpu); 1137 dst_rq = cpu_rq(arg->dst_cpu); 1138 1139 double_raw_lock(&arg->src_task->pi_lock, 1140 &arg->dst_task->pi_lock); 1141 double_rq_lock(src_rq, dst_rq); 1142 if (task_cpu(arg->dst_task) != arg->dst_cpu) 1143 goto unlock; 1144 1145 if (task_cpu(arg->src_task) != arg->src_cpu) 1146 goto unlock; 1147 1148 if (!cpumask_test_cpu(arg->dst_cpu, tsk_cpus_allowed(arg->src_task))) 1149 goto unlock; 1150 1151 if (!cpumask_test_cpu(arg->src_cpu, tsk_cpus_allowed(arg->dst_task))) 1152 goto unlock; 1153 1154 __migrate_swap_task(arg->src_task, arg->dst_cpu); 1155 __migrate_swap_task(arg->dst_task, arg->src_cpu); 1156 1157 ret = 0; 1158 1159unlock: 1160 double_rq_unlock(src_rq, dst_rq); 1161 raw_spin_unlock(&arg->dst_task->pi_lock); 1162 raw_spin_unlock(&arg->src_task->pi_lock); 1163 1164 return ret; 1165} 1166 1167/* 1168 * Cross migrate two tasks 1169 */ 1170int migrate_swap(struct task_struct *cur, struct task_struct *p) 1171{ 1172 struct migration_swap_arg arg; 1173 int ret = -EINVAL; 1174 1175 arg = (struct migration_swap_arg){ 1176 .src_task = cur, 1177 .src_cpu = task_cpu(cur), 1178 .dst_task = p, 1179 .dst_cpu = task_cpu(p), 1180 }; 1181 1182 if (arg.src_cpu == arg.dst_cpu) 1183 goto out; 1184 1185 /* 1186 * These three tests are all lockless; this is OK since all of them 1187 * will be re-checked with proper locks held further down the line. 1188 */ 1189 if (!cpu_active(arg.src_cpu) || !cpu_active(arg.dst_cpu)) 1190 goto out; 1191 1192 if (!cpumask_test_cpu(arg.dst_cpu, tsk_cpus_allowed(arg.src_task))) 1193 goto out; 1194 1195 if (!cpumask_test_cpu(arg.src_cpu, tsk_cpus_allowed(arg.dst_task))) 1196 goto out; 1197 1198 trace_sched_swap_numa(cur, arg.src_cpu, p, arg.dst_cpu); 1199 ret = stop_two_cpus(arg.dst_cpu, arg.src_cpu, migrate_swap_stop, &arg); 1200 1201out: 1202 return ret; 1203} 1204 1205struct migration_arg { 1206 struct task_struct *task; 1207 int dest_cpu; 1208}; 1209 1210static int migration_cpu_stop(void *data); 1211 1212/* 1213 * wait_task_inactive - wait for a thread to unschedule. 1214 * 1215 * If @match_state is nonzero, it's the @p->state value just checked and 1216 * not expected to change. If it changes, i.e. @p might have woken up, 1217 * then return zero. When we succeed in waiting for @p to be off its CPU, 1218 * we return a positive number (its total switch count). If a second call 1219 * a short while later returns the same number, the caller can be sure that 1220 * @p has remained unscheduled the whole time. 1221 * 1222 * The caller must ensure that the task *will* unschedule sometime soon, 1223 * else this function might spin for a *long* time. This function can't 1224 * be called with interrupts off, or it may introduce deadlock with 1225 * smp_call_function() if an IPI is sent by the same process we are 1226 * waiting to become inactive. 1227 */ 1228unsigned long wait_task_inactive(struct task_struct *p, long match_state) 1229{ 1230 unsigned long flags; 1231 int running, queued; 1232 unsigned long ncsw; 1233 struct rq *rq; 1234 1235 for (;;) { 1236 /* 1237 * We do the initial early heuristics without holding 1238 * any task-queue locks at all. We'll only try to get 1239 * the runqueue lock when things look like they will 1240 * work out! 1241 */ 1242 rq = task_rq(p); 1243 1244 /* 1245 * If the task is actively running on another CPU 1246 * still, just relax and busy-wait without holding 1247 * any locks. 1248 * 1249 * NOTE! Since we don't hold any locks, it's not 1250 * even sure that "rq" stays as the right runqueue! 1251 * But we don't care, since "task_running()" will 1252 * return false if the runqueue has changed and p 1253 * is actually now running somewhere else! 1254 */ 1255 while (task_running(rq, p)) { 1256 if (match_state && unlikely(p->state != match_state)) 1257 return 0; 1258 cpu_relax(); 1259 } 1260 1261 /* 1262 * Ok, time to look more closely! We need the rq 1263 * lock now, to be *sure*. If we're wrong, we'll 1264 * just go back and repeat. 1265 */ 1266 rq = task_rq_lock(p, &flags); 1267 trace_sched_wait_task(p); 1268 running = task_running(rq, p); 1269 queued = task_on_rq_queued(p); 1270 ncsw = 0; 1271 if (!match_state || p->state == match_state) 1272 ncsw = p->nvcsw | LONG_MIN; /* sets MSB */ 1273 task_rq_unlock(rq, p, &flags); 1274 1275 /* 1276 * If it changed from the expected state, bail out now. 1277 */ 1278 if (unlikely(!ncsw)) 1279 break; 1280 1281 /* 1282 * Was it really running after all now that we 1283 * checked with the proper locks actually held? 1284 * 1285 * Oops. Go back and try again.. 1286 */ 1287 if (unlikely(running)) { 1288 cpu_relax(); 1289 continue; 1290 } 1291 1292 /* 1293 * It's not enough that it's not actively running, 1294 * it must be off the runqueue _entirely_, and not 1295 * preempted! 1296 * 1297 * So if it was still runnable (but just not actively 1298 * running right now), it's preempted, and we should 1299 * yield - it could be a while. 1300 */ 1301 if (unlikely(queued)) { 1302 ktime_t to = ktime_set(0, NSEC_PER_SEC/HZ); 1303 1304 set_current_state(TASK_UNINTERRUPTIBLE); 1305 schedule_hrtimeout(&to, HRTIMER_MODE_REL); 1306 continue; 1307 } 1308 1309 /* 1310 * Ahh, all good. It wasn't running, and it wasn't 1311 * runnable, which means that it will never become 1312 * running in the future either. We're all done! 1313 */ 1314 break; 1315 } 1316 1317 return ncsw; 1318} 1319 1320/*** 1321 * kick_process - kick a running thread to enter/exit the kernel 1322 * @p: the to-be-kicked thread 1323 * 1324 * Cause a process which is running on another CPU to enter 1325 * kernel-mode, without any delay. (to get signals handled.) 1326 * 1327 * NOTE: this function doesn't have to take the runqueue lock, 1328 * because all it wants to ensure is that the remote task enters 1329 * the kernel. If the IPI races and the task has been migrated 1330 * to another CPU then no harm is done and the purpose has been 1331 * achieved as well. 1332 */ 1333void kick_process(struct task_struct *p) 1334{ 1335 int cpu; 1336 1337 preempt_disable(); 1338 cpu = task_cpu(p); 1339 if ((cpu != smp_processor_id()) && task_curr(p)) 1340 smp_send_reschedule(cpu); 1341 preempt_enable(); 1342} 1343EXPORT_SYMBOL_GPL(kick_process); 1344#endif /* CONFIG_SMP */ 1345 1346#ifdef CONFIG_SMP 1347/* 1348 * ->cpus_allowed is protected by both rq->lock and p->pi_lock 1349 */ 1350static int select_fallback_rq(int cpu, struct task_struct *p) 1351{ 1352 int nid = cpu_to_node(cpu); 1353 const struct cpumask *nodemask = NULL; 1354 enum { cpuset, possible, fail } state = cpuset; 1355 int dest_cpu; 1356 1357 /* 1358 * If the node that the cpu is on has been offlined, cpu_to_node() 1359 * will return -1. There is no cpu on the node, and we should 1360 * select the cpu on the other node. 1361 */ 1362 if (nid != -1) { 1363 nodemask = cpumask_of_node(nid); 1364 1365 /* Look for allowed, online CPU in same node. */ 1366 for_each_cpu(dest_cpu, nodemask) { 1367 if (!cpu_online(dest_cpu)) 1368 continue; 1369 if (!cpu_active(dest_cpu)) 1370 continue; 1371 if (cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) 1372 return dest_cpu; 1373 } 1374 } 1375 1376 for (;;) { 1377 /* Any allowed, online CPU? */ 1378 for_each_cpu(dest_cpu, tsk_cpus_allowed(p)) { 1379 if (!cpu_online(dest_cpu)) 1380 continue; 1381 if (!cpu_active(dest_cpu)) 1382 continue; 1383 goto out; 1384 } 1385 1386 switch (state) { 1387 case cpuset: 1388 /* No more Mr. Nice Guy. */ 1389 cpuset_cpus_allowed_fallback(p); 1390 state = possible; 1391 break; 1392 1393 case possible: 1394 do_set_cpus_allowed(p, cpu_possible_mask); 1395 state = fail; 1396 break; 1397 1398 case fail: 1399 BUG(); 1400 break; 1401 } 1402 } 1403 1404out: 1405 if (state != cpuset) { 1406 /* 1407 * Don't tell them about moving exiting tasks or 1408 * kernel threads (both mm NULL), since they never 1409 * leave kernel. 1410 */ 1411 if (p->mm && printk_ratelimit()) { 1412 printk_deferred("process %d (%s) no longer affine to cpu%d\n", 1413 task_pid_nr(p), p->comm, cpu); 1414 } 1415 } 1416 1417 return dest_cpu; 1418} 1419 1420/* 1421 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable. 1422 */ 1423static inline 1424int select_task_rq(struct task_struct *p, int cpu, int sd_flags, int wake_flags) 1425{ 1426 cpu = p->sched_class->select_task_rq(p, cpu, sd_flags, wake_flags); 1427 1428 /* 1429 * In order not to call set_task_cpu() on a blocking task we need 1430 * to rely on ttwu() to place the task on a valid ->cpus_allowed 1431 * cpu. 1432 * 1433 * Since this is common to all placement strategies, this lives here. 1434 * 1435 * [ this allows ->select_task() to simply return task_cpu(p) and 1436 * not worry about this generic constraint ] 1437 */ 1438 if (unlikely(!cpumask_test_cpu(cpu, tsk_cpus_allowed(p)) || 1439 !cpu_online(cpu))) 1440 cpu = select_fallback_rq(task_cpu(p), p); 1441 1442 return cpu; 1443} 1444 1445static void update_avg(u64 *avg, u64 sample) 1446{ 1447 s64 diff = sample - *avg; 1448 *avg += diff >> 3; 1449} 1450#endif 1451 1452static void 1453ttwu_stat(struct task_struct *p, int cpu, int wake_flags) 1454{ 1455#ifdef CONFIG_SCHEDSTATS 1456 struct rq *rq = this_rq(); 1457 1458#ifdef CONFIG_SMP 1459 int this_cpu = smp_processor_id(); 1460 1461 if (cpu == this_cpu) { 1462 schedstat_inc(rq, ttwu_local); 1463 schedstat_inc(p, se.statistics.nr_wakeups_local); 1464 } else { 1465 struct sched_domain *sd; 1466 1467 schedstat_inc(p, se.statistics.nr_wakeups_remote); 1468 rcu_read_lock(); 1469 for_each_domain(this_cpu, sd) { 1470 if (cpumask_test_cpu(cpu, sched_domain_span(sd))) { 1471 schedstat_inc(sd, ttwu_wake_remote); 1472 break; 1473 } 1474 } 1475 rcu_read_unlock(); 1476 } 1477 1478 if (wake_flags & WF_MIGRATED) 1479 schedstat_inc(p, se.statistics.nr_wakeups_migrate); 1480 1481#endif /* CONFIG_SMP */ 1482 1483 schedstat_inc(rq, ttwu_count); 1484 schedstat_inc(p, se.statistics.nr_wakeups); 1485 1486 if (wake_flags & WF_SYNC) 1487 schedstat_inc(p, se.statistics.nr_wakeups_sync); 1488 1489#endif /* CONFIG_SCHEDSTATS */ 1490} 1491 1492static void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags) 1493{ 1494 activate_task(rq, p, en_flags); 1495 p->on_rq = TASK_ON_RQ_QUEUED; 1496 1497 /* if a worker is waking up, notify workqueue */ 1498 if (p->flags & PF_WQ_WORKER) 1499 wq_worker_waking_up(p, cpu_of(rq)); 1500} 1501 1502/* 1503 * Mark the task runnable and perform wakeup-preemption. 1504 */ 1505static void 1506ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags) 1507{ 1508 check_preempt_curr(rq, p, wake_flags); 1509 trace_sched_wakeup(p, true); 1510 1511 p->state = TASK_RUNNING; 1512#ifdef CONFIG_SMP 1513 if (p->sched_class->task_woken) 1514 p->sched_class->task_woken(rq, p); 1515 1516 if (rq->idle_stamp) { 1517 u64 delta = rq_clock(rq) - rq->idle_stamp; 1518 u64 max = 2*rq->max_idle_balance_cost; 1519 1520 update_avg(&rq->avg_idle, delta); 1521 1522 if (rq->avg_idle > max) 1523 rq->avg_idle = max; 1524 1525 rq->idle_stamp = 0; 1526 } 1527#endif 1528} 1529 1530static void 1531ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags) 1532{ 1533#ifdef CONFIG_SMP 1534 if (p->sched_contributes_to_load) 1535 rq->nr_uninterruptible--; 1536#endif 1537 1538 ttwu_activate(rq, p, ENQUEUE_WAKEUP | ENQUEUE_WAKING); 1539 ttwu_do_wakeup(rq, p, wake_flags); 1540} 1541 1542/* 1543 * Called in case the task @p isn't fully descheduled from its runqueue, 1544 * in this case we must do a remote wakeup. Its a 'light' wakeup though, 1545 * since all we need to do is flip p->state to TASK_RUNNING, since 1546 * the task is still ->on_rq. 1547 */ 1548static int ttwu_remote(struct task_struct *p, int wake_flags) 1549{ 1550 struct rq *rq; 1551 int ret = 0; 1552 1553 rq = __task_rq_lock(p); 1554 if (task_on_rq_queued(p)) { 1555 /* check_preempt_curr() may use rq clock */ 1556 update_rq_clock(rq); 1557 ttwu_do_wakeup(rq, p, wake_flags); 1558 ret = 1; 1559 } 1560 __task_rq_unlock(rq); 1561 1562 return ret; 1563} 1564 1565#ifdef CONFIG_SMP 1566void sched_ttwu_pending(void) 1567{ 1568 struct rq *rq = this_rq(); 1569 struct llist_node *llist = llist_del_all(&rq->wake_list); 1570 struct task_struct *p; 1571 unsigned long flags; 1572 1573 if (!llist) 1574 return; 1575 1576 raw_spin_lock_irqsave(&rq->lock, flags); 1577 1578 while (llist) { 1579 p = llist_entry(llist, struct task_struct, wake_entry); 1580 llist = llist_next(llist); 1581 ttwu_do_activate(rq, p, 0); 1582 } 1583 1584 raw_spin_unlock_irqrestore(&rq->lock, flags); 1585} 1586 1587void scheduler_ipi(void) 1588{ 1589 /* 1590 * Fold TIF_NEED_RESCHED into the preempt_count; anybody setting 1591 * TIF_NEED_RESCHED remotely (for the first time) will also send 1592 * this IPI. 1593 */ 1594 preempt_fold_need_resched(); 1595 1596 if (llist_empty(&this_rq()->wake_list) && !got_nohz_idle_kick()) 1597 return; 1598 1599 /* 1600 * Not all reschedule IPI handlers call irq_enter/irq_exit, since 1601 * traditionally all their work was done from the interrupt return 1602 * path. Now that we actually do some work, we need to make sure 1603 * we do call them. 1604 * 1605 * Some archs already do call them, luckily irq_enter/exit nest 1606 * properly. 1607 * 1608 * Arguably we should visit all archs and update all handlers, 1609 * however a fair share of IPIs are still resched only so this would 1610 * somewhat pessimize the simple resched case. 1611 */ 1612 irq_enter(); 1613 sched_ttwu_pending(); 1614 1615 /* 1616 * Check if someone kicked us for doing the nohz idle load balance. 1617 */ 1618 if (unlikely(got_nohz_idle_kick())) { 1619 this_rq()->idle_balance = 1; 1620 raise_softirq_irqoff(SCHED_SOFTIRQ); 1621 } 1622 irq_exit(); 1623} 1624 1625static void ttwu_queue_remote(struct task_struct *p, int cpu) 1626{ 1627 struct rq *rq = cpu_rq(cpu); 1628 1629 if (llist_add(&p->wake_entry, &cpu_rq(cpu)->wake_list)) { 1630 if (!set_nr_if_polling(rq->idle)) 1631 smp_send_reschedule(cpu); 1632 else 1633 trace_sched_wake_idle_without_ipi(cpu); 1634 } 1635} 1636 1637bool cpus_share_cache(int this_cpu, int that_cpu) 1638{ 1639 return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu); 1640} 1641#endif /* CONFIG_SMP */ 1642 1643static void ttwu_queue(struct task_struct *p, int cpu) 1644{ 1645 struct rq *rq = cpu_rq(cpu); 1646 1647#if defined(CONFIG_SMP) 1648 if (sched_feat(TTWU_QUEUE) && !cpus_share_cache(smp_processor_id(), cpu)) { 1649 sched_clock_cpu(cpu); /* sync clocks x-cpu */ 1650 ttwu_queue_remote(p, cpu); 1651 return; 1652 } 1653#endif 1654 1655 raw_spin_lock(&rq->lock); 1656 ttwu_do_activate(rq, p, 0); 1657 raw_spin_unlock(&rq->lock); 1658} 1659 1660/** 1661 * try_to_wake_up - wake up a thread 1662 * @p: the thread to be awakened 1663 * @state: the mask of task states that can be woken 1664 * @wake_flags: wake modifier flags (WF_*) 1665 * 1666 * Put it on the run-queue if it's not already there. The "current" 1667 * thread is always on the run-queue (except when the actual 1668 * re-schedule is in progress), and as such you're allowed to do 1669 * the simpler "current->state = TASK_RUNNING" to mark yourself 1670 * runnable without the overhead of this. 1671 * 1672 * Return: %true if @p was woken up, %false if it was already running. 1673 * or @state didn't match @p's state. 1674 */ 1675static int 1676try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) 1677{ 1678 unsigned long flags; 1679 int cpu, success = 0; 1680 1681 /* 1682 * If we are going to wake up a thread waiting for CONDITION we 1683 * need to ensure that CONDITION=1 done by the caller can not be 1684 * reordered with p->state check below. This pairs with mb() in 1685 * set_current_state() the waiting thread does. 1686 */ 1687 smp_mb__before_spinlock(); 1688 raw_spin_lock_irqsave(&p->pi_lock, flags); 1689 if (!(p->state & state)) 1690 goto out; 1691 1692 success = 1; /* we're going to change ->state */ 1693 cpu = task_cpu(p); 1694 1695 if (p->on_rq && ttwu_remote(p, wake_flags)) 1696 goto stat; 1697 1698#ifdef CONFIG_SMP 1699 /* 1700 * If the owning (remote) cpu is still in the middle of schedule() with 1701 * this task as prev, wait until its done referencing the task. 1702 */ 1703 while (p->on_cpu) 1704 cpu_relax(); 1705 /* 1706 * Pairs with the smp_wmb() in finish_lock_switch(). 1707 */ 1708 smp_rmb(); 1709 1710 p->sched_contributes_to_load = !!task_contributes_to_load(p); 1711 p->state = TASK_WAKING; 1712 1713 if (p->sched_class->task_waking) 1714 p->sched_class->task_waking(p); 1715 1716 cpu = select_task_rq(p, p->wake_cpu, SD_BALANCE_WAKE, wake_flags); 1717 if (task_cpu(p) != cpu) { 1718 wake_flags |= WF_MIGRATED; 1719 set_task_cpu(p, cpu); 1720 } 1721#endif /* CONFIG_SMP */ 1722 1723 ttwu_queue(p, cpu); 1724stat: 1725 ttwu_stat(p, cpu, wake_flags); 1726out: 1727 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 1728 1729 return success; 1730} 1731 1732/** 1733 * try_to_wake_up_local - try to wake up a local task with rq lock held 1734 * @p: the thread to be awakened 1735 * 1736 * Put @p on the run-queue if it's not already there. The caller must 1737 * ensure that this_rq() is locked, @p is bound to this_rq() and not 1738 * the current task. 1739 */ 1740static void try_to_wake_up_local(struct task_struct *p) 1741{ 1742 struct rq *rq = task_rq(p); 1743 1744 if (WARN_ON_ONCE(rq != this_rq()) || 1745 WARN_ON_ONCE(p == current)) 1746 return; 1747 1748 lockdep_assert_held(&rq->lock); 1749 1750 if (!raw_spin_trylock(&p->pi_lock)) { 1751 raw_spin_unlock(&rq->lock); 1752 raw_spin_lock(&p->pi_lock); 1753 raw_spin_lock(&rq->lock); 1754 } 1755 1756 if (!(p->state & TASK_NORMAL)) 1757 goto out; 1758 1759 if (!task_on_rq_queued(p)) 1760 ttwu_activate(rq, p, ENQUEUE_WAKEUP); 1761 1762 ttwu_do_wakeup(rq, p, 0); 1763 ttwu_stat(p, smp_processor_id(), 0); 1764out: 1765 raw_spin_unlock(&p->pi_lock); 1766} 1767 1768/** 1769 * wake_up_process - Wake up a specific process 1770 * @p: The process to be woken up. 1771 * 1772 * Attempt to wake up the nominated process and move it to the set of runnable 1773 * processes. 1774 * 1775 * Return: 1 if the process was woken up, 0 if it was already running. 1776 * 1777 * It may be assumed that this function implies a write memory barrier before 1778 * changing the task state if and only if any tasks are woken up. 1779 */ 1780int wake_up_process(struct task_struct *p) 1781{ 1782 WARN_ON(task_is_stopped_or_traced(p)); 1783 return try_to_wake_up(p, TASK_NORMAL, 0); 1784} 1785EXPORT_SYMBOL(wake_up_process); 1786 1787int wake_up_state(struct task_struct *p, unsigned int state) 1788{ 1789 return try_to_wake_up(p, state, 0); 1790} 1791 1792/* 1793 * Perform scheduler related setup for a newly forked process p. 1794 * p is forked by current. 1795 * 1796 * __sched_fork() is basic setup used by init_idle() too: 1797 */ 1798static void __sched_fork(unsigned long clone_flags, struct task_struct *p) 1799{ 1800 p->on_rq = 0; 1801 1802 p->se.on_rq = 0; 1803 p->se.exec_start = 0; 1804 p->se.sum_exec_runtime = 0; 1805 p->se.prev_sum_exec_runtime = 0; 1806 p->se.nr_migrations = 0; 1807 p->se.vruntime = 0; 1808 INIT_LIST_HEAD(&p->se.group_node); 1809 1810#ifdef CONFIG_SCHEDSTATS 1811 memset(&p->se.statistics, 0, sizeof(p->se.statistics)); 1812#endif 1813 1814 RB_CLEAR_NODE(&p->dl.rb_node); 1815 hrtimer_init(&p->dl.dl_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 1816 p->dl.dl_runtime = p->dl.runtime = 0; 1817 p->dl.dl_deadline = p->dl.deadline = 0; 1818 p->dl.dl_period = 0; 1819 p->dl.flags = 0; 1820 1821 INIT_LIST_HEAD(&p->rt.run_list); 1822 1823#ifdef CONFIG_PREEMPT_NOTIFIERS 1824 INIT_HLIST_HEAD(&p->preempt_notifiers); 1825#endif 1826 1827#ifdef CONFIG_NUMA_BALANCING 1828 if (p->mm && atomic_read(&p->mm->mm_users) == 1) { 1829 p->mm->numa_next_scan = jiffies + msecs_to_jiffies(sysctl_numa_balancing_scan_delay); 1830 p->mm->numa_scan_seq = 0; 1831 } 1832 1833 if (clone_flags & CLONE_VM) 1834 p->numa_preferred_nid = current->numa_preferred_nid; 1835 else 1836 p->numa_preferred_nid = -1; 1837 1838 p->node_stamp = 0ULL; 1839 p->numa_scan_seq = p->mm ? p->mm->numa_scan_seq : 0; 1840 p->numa_scan_period = sysctl_numa_balancing_scan_delay; 1841 p->numa_work.next = &p->numa_work; 1842 p->numa_faults_memory = NULL; 1843 p->numa_faults_buffer_memory = NULL; 1844 p->last_task_numa_placement = 0; 1845 p->last_sum_exec_runtime = 0; 1846 1847 INIT_LIST_HEAD(&p->numa_entry); 1848 p->numa_group = NULL; 1849#endif /* CONFIG_NUMA_BALANCING */ 1850} 1851 1852#ifdef CONFIG_NUMA_BALANCING 1853#ifdef CONFIG_SCHED_DEBUG 1854void set_numabalancing_state(bool enabled) 1855{ 1856 if (enabled) 1857 sched_feat_set("NUMA"); 1858 else 1859 sched_feat_set("NO_NUMA"); 1860} 1861#else 1862__read_mostly bool numabalancing_enabled; 1863 1864void set_numabalancing_state(bool enabled) 1865{ 1866 numabalancing_enabled = enabled; 1867} 1868#endif /* CONFIG_SCHED_DEBUG */ 1869 1870#ifdef CONFIG_PROC_SYSCTL 1871int sysctl_numa_balancing(struct ctl_table *table, int write, 1872 void __user *buffer, size_t *lenp, loff_t *ppos) 1873{ 1874 struct ctl_table t; 1875 int err; 1876 int state = numabalancing_enabled; 1877 1878 if (write && !capable(CAP_SYS_ADMIN)) 1879 return -EPERM; 1880 1881 t = *table; 1882 t.data = &state; 1883 err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos); 1884 if (err < 0) 1885 return err; 1886 if (write) 1887 set_numabalancing_state(state); 1888 return err; 1889} 1890#endif 1891#endif 1892 1893/* 1894 * fork()/clone()-time setup: 1895 */ 1896int sched_fork(unsigned long clone_flags, struct task_struct *p) 1897{ 1898 unsigned long flags; 1899 int cpu = get_cpu(); 1900 1901 __sched_fork(clone_flags, p); 1902 /* 1903 * We mark the process as running here. This guarantees that 1904 * nobody will actually run it, and a signal or other external 1905 * event cannot wake it up and insert it on the runqueue either. 1906 */ 1907 p->state = TASK_RUNNING; 1908 1909 /* 1910 * Make sure we do not leak PI boosting priority to the child. 1911 */ 1912 p->prio = current->normal_prio; 1913 1914 /* 1915 * Revert to default priority/policy on fork if requested. 1916 */ 1917 if (unlikely(p->sched_reset_on_fork)) { 1918 if (task_has_dl_policy(p) || task_has_rt_policy(p)) { 1919 p->policy = SCHED_NORMAL; 1920 p->static_prio = NICE_TO_PRIO(0); 1921 p->rt_priority = 0; 1922 } else if (PRIO_TO_NICE(p->static_prio) < 0) 1923 p->static_prio = NICE_TO_PRIO(0); 1924 1925 p->prio = p->normal_prio = __normal_prio(p); 1926 set_load_weight(p); 1927 1928 /* 1929 * We don't need the reset flag anymore after the fork. It has 1930 * fulfilled its duty: 1931 */ 1932 p->sched_reset_on_fork = 0; 1933 } 1934 1935 if (dl_prio(p->prio)) { 1936 put_cpu(); 1937 return -EAGAIN; 1938 } else if (rt_prio(p->prio)) { 1939 p->sched_class = &rt_sched_class; 1940 } else { 1941 p->sched_class = &fair_sched_class; 1942 } 1943 1944 if (p->sched_class->task_fork) 1945 p->sched_class->task_fork(p); 1946 1947 /* 1948 * The child is not yet in the pid-hash so no cgroup attach races, 1949 * and the cgroup is pinned to this child due to cgroup_fork() 1950 * is ran before sched_fork(). 1951 * 1952 * Silence PROVE_RCU. 1953 */ 1954 raw_spin_lock_irqsave(&p->pi_lock, flags); 1955 set_task_cpu(p, cpu); 1956 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 1957 1958#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) 1959 if (likely(sched_info_on())) 1960 memset(&p->sched_info, 0, sizeof(p->sched_info)); 1961#endif 1962#if defined(CONFIG_SMP) 1963 p->on_cpu = 0; 1964#endif 1965 init_task_preempt_count(p); 1966#ifdef CONFIG_SMP 1967 plist_node_init(&p->pushable_tasks, MAX_PRIO); 1968 RB_CLEAR_NODE(&p->pushable_dl_tasks); 1969#endif 1970 1971 put_cpu(); 1972 return 0; 1973} 1974 1975unsigned long to_ratio(u64 period, u64 runtime) 1976{ 1977 if (runtime == RUNTIME_INF) 1978 return 1ULL << 20; 1979 1980 /* 1981 * Doing this here saves a lot of checks in all 1982 * the calling paths, and returning zero seems 1983 * safe for them anyway. 1984 */ 1985 if (period == 0) 1986 return 0; 1987 1988 return div64_u64(runtime << 20, period); 1989} 1990 1991#ifdef CONFIG_SMP 1992inline struct dl_bw *dl_bw_of(int i) 1993{ 1994 return &cpu_rq(i)->rd->dl_bw; 1995} 1996 1997static inline int dl_bw_cpus(int i) 1998{ 1999 struct root_domain *rd = cpu_rq(i)->rd; 2000 int cpus = 0; 2001 2002 for_each_cpu_and(i, rd->span, cpu_active_mask) 2003 cpus++; 2004 2005 return cpus; 2006} 2007#else 2008inline struct dl_bw *dl_bw_of(int i) 2009{ 2010 return &cpu_rq(i)->dl.dl_bw; 2011} 2012 2013static inline int dl_bw_cpus(int i) 2014{ 2015 return 1; 2016} 2017#endif 2018 2019static inline 2020void __dl_clear(struct dl_bw *dl_b, u64 tsk_bw) 2021{ 2022 dl_b->total_bw -= tsk_bw; 2023} 2024 2025static inline 2026void __dl_add(struct dl_bw *dl_b, u64 tsk_bw) 2027{ 2028 dl_b->total_bw += tsk_bw; 2029} 2030 2031static inline 2032bool __dl_overflow(struct dl_bw *dl_b, int cpus, u64 old_bw, u64 new_bw) 2033{ 2034 return dl_b->bw != -1 && 2035 dl_b->bw * cpus < dl_b->total_bw - old_bw + new_bw; 2036} 2037 2038/* 2039 * We must be sure that accepting a new task (or allowing changing the 2040 * parameters of an existing one) is consistent with the bandwidth 2041 * constraints. If yes, this function also accordingly updates the currently 2042 * allocated bandwidth to reflect the new situation. 2043 * 2044 * This function is called while holding p's rq->lock. 2045 */ 2046static int dl_overflow(struct task_struct *p, int policy, 2047 const struct sched_attr *attr) 2048{ 2049 2050 struct dl_bw *dl_b = dl_bw_of(task_cpu(p)); 2051 u64 period = attr->sched_period ?: attr->sched_deadline; 2052 u64 runtime = attr->sched_runtime; 2053 u64 new_bw = dl_policy(policy) ? to_ratio(period, runtime) : 0; 2054 int cpus, err = -1; 2055 2056 if (new_bw == p->dl.dl_bw) 2057 return 0; 2058 2059 /* 2060 * Either if a task, enters, leave, or stays -deadline but changes 2061 * its parameters, we may need to update accordingly the total 2062 * allocated bandwidth of the container. 2063 */ 2064 raw_spin_lock(&dl_b->lock); 2065 cpus = dl_bw_cpus(task_cpu(p)); 2066 if (dl_policy(policy) && !task_has_dl_policy(p) && 2067 !__dl_overflow(dl_b, cpus, 0, new_bw)) { 2068 __dl_add(dl_b, new_bw); 2069 err = 0; 2070 } else if (dl_policy(policy) && task_has_dl_policy(p) && 2071 !__dl_overflow(dl_b, cpus, p->dl.dl_bw, new_bw)) { 2072 __dl_clear(dl_b, p->dl.dl_bw); 2073 __dl_add(dl_b, new_bw); 2074 err = 0; 2075 } else if (!dl_policy(policy) && task_has_dl_policy(p)) { 2076 __dl_clear(dl_b, p->dl.dl_bw); 2077 err = 0; 2078 } 2079 raw_spin_unlock(&dl_b->lock); 2080 2081 return err; 2082} 2083 2084extern void init_dl_bw(struct dl_bw *dl_b); 2085 2086/* 2087 * wake_up_new_task - wake up a newly created task for the first time. 2088 * 2089 * This function will do some initial scheduler statistics housekeeping 2090 * that must be done for every newly created context, then puts the task 2091 * on the runqueue and wakes it. 2092 */ 2093void wake_up_new_task(struct task_struct *p) 2094{ 2095 unsigned long flags; 2096 struct rq *rq; 2097 2098 raw_spin_lock_irqsave(&p->pi_lock, flags); 2099#ifdef CONFIG_SMP 2100 /* 2101 * Fork balancing, do it here and not earlier because: 2102 * - cpus_allowed can change in the fork path 2103 * - any previously selected cpu might disappear through hotplug 2104 */ 2105 set_task_cpu(p, select_task_rq(p, task_cpu(p), SD_BALANCE_FORK, 0)); 2106#endif 2107 2108 /* Initialize new task's runnable average */ 2109 init_task_runnable_average(p); 2110 rq = __task_rq_lock(p); 2111 activate_task(rq, p, 0); 2112 p->on_rq = TASK_ON_RQ_QUEUED; 2113 trace_sched_wakeup_new(p, true); 2114 check_preempt_curr(rq, p, WF_FORK); 2115#ifdef CONFIG_SMP 2116 if (p->sched_class->task_woken) 2117 p->sched_class->task_woken(rq, p); 2118#endif 2119 task_rq_unlock(rq, p, &flags); 2120} 2121 2122#ifdef CONFIG_PREEMPT_NOTIFIERS 2123 2124/** 2125 * preempt_notifier_register - tell me when current is being preempted & rescheduled 2126 * @notifier: notifier struct to register 2127 */ 2128void preempt_notifier_register(struct preempt_notifier *notifier) 2129{ 2130 hlist_add_head(¬ifier->link, ¤t->preempt_notifiers); 2131} 2132EXPORT_SYMBOL_GPL(preempt_notifier_register); 2133 2134/** 2135 * preempt_notifier_unregister - no longer interested in preemption notifications 2136 * @notifier: notifier struct to unregister 2137 * 2138 * This is safe to call from within a preemption notifier. 2139 */ 2140void preempt_notifier_unregister(struct preempt_notifier *notifier) 2141{ 2142 hlist_del(¬ifier->link); 2143} 2144EXPORT_SYMBOL_GPL(preempt_notifier_unregister); 2145 2146static void fire_sched_in_preempt_notifiers(struct task_struct *curr) 2147{ 2148 struct preempt_notifier *notifier; 2149 2150 hlist_for_each_entry(notifier, &curr->preempt_notifiers, link) 2151 notifier->ops->sched_in(notifier, raw_smp_processor_id()); 2152} 2153 2154static void 2155fire_sched_out_preempt_notifiers(struct task_struct *curr, 2156 struct task_struct *next) 2157{ 2158 struct preempt_notifier *notifier; 2159 2160 hlist_for_each_entry(notifier, &curr->preempt_notifiers, link) 2161 notifier->ops->sched_out(notifier, next); 2162} 2163 2164#else /* !CONFIG_PREEMPT_NOTIFIERS */ 2165 2166static void fire_sched_in_preempt_notifiers(struct task_struct *curr) 2167{ 2168} 2169 2170static void 2171fire_sched_out_preempt_notifiers(struct task_struct *curr, 2172 struct task_struct *next) 2173{ 2174} 2175 2176#endif /* CONFIG_PREEMPT_NOTIFIERS */ 2177 2178/** 2179 * prepare_task_switch - prepare to switch tasks 2180 * @rq: the runqueue preparing to switch 2181 * @prev: the current task that is being switched out 2182 * @next: the task we are going to switch to. 2183 * 2184 * This is called with the rq lock held and interrupts off. It must 2185 * be paired with a subsequent finish_task_switch after the context 2186 * switch. 2187 * 2188 * prepare_task_switch sets up locking and calls architecture specific 2189 * hooks. 2190 */ 2191static inline void 2192prepare_task_switch(struct rq *rq, struct task_struct *prev, 2193 struct task_struct *next) 2194{ 2195 trace_sched_switch(prev, next); 2196 sched_info_switch(rq, prev, next); 2197 perf_event_task_sched_out(prev, next); 2198 fire_sched_out_preempt_notifiers(prev, next); 2199 prepare_lock_switch(rq, next); 2200 prepare_arch_switch(next); 2201} 2202 2203/** 2204 * finish_task_switch - clean up after a task-switch 2205 * @rq: runqueue associated with task-switch 2206 * @prev: the thread we just switched away from. 2207 * 2208 * finish_task_switch must be called after the context switch, paired 2209 * with a prepare_task_switch call before the context switch. 2210 * finish_task_switch will reconcile locking set up by prepare_task_switch, 2211 * and do any other architecture-specific cleanup actions. 2212 * 2213 * Note that we may have delayed dropping an mm in context_switch(). If 2214 * so, we finish that here outside of the runqueue lock. (Doing it 2215 * with the lock held can cause deadlocks; see schedule() for 2216 * details.) 2217 */ 2218static void finish_task_switch(struct rq *rq, struct task_struct *prev) 2219 __releases(rq->lock) 2220{ 2221 struct mm_struct *mm = rq->prev_mm; 2222 long prev_state; 2223 2224 rq->prev_mm = NULL; 2225 2226 /* 2227 * A task struct has one reference for the use as "current". 2228 * If a task dies, then it sets TASK_DEAD in tsk->state and calls 2229 * schedule one last time. The schedule call will never return, and 2230 * the scheduled task must drop that reference. 2231 * The test for TASK_DEAD must occur while the runqueue locks are 2232 * still held, otherwise prev could be scheduled on another cpu, die 2233 * there before we look at prev->state, and then the reference would 2234 * be dropped twice. 2235 * Manfred Spraul <manfred@colorfullife.com> 2236 */ 2237 prev_state = prev->state; 2238 vtime_task_switch(prev); 2239 finish_arch_switch(prev); 2240 perf_event_task_sched_in(prev, current); 2241 finish_lock_switch(rq, prev); 2242 finish_arch_post_lock_switch(); 2243 2244 fire_sched_in_preempt_notifiers(current); 2245 if (mm) 2246 mmdrop(mm); 2247 if (unlikely(prev_state == TASK_DEAD)) { 2248 if (prev->sched_class->task_dead) 2249 prev->sched_class->task_dead(prev); 2250 2251 /* 2252 * Remove function-return probe instances associated with this 2253 * task and put them back on the free list. 2254 */ 2255 kprobe_flush_task(prev); 2256 put_task_struct(prev); 2257 } 2258 2259 tick_nohz_task_switch(current); 2260} 2261 2262#ifdef CONFIG_SMP 2263 2264/* rq->lock is NOT held, but preemption is disabled */ 2265static inline void post_schedule(struct rq *rq) 2266{ 2267 if (rq->post_schedule) { 2268 unsigned long flags; 2269 2270 raw_spin_lock_irqsave(&rq->lock, flags); 2271 if (rq->curr->sched_class->post_schedule) 2272 rq->curr->sched_class->post_schedule(rq); 2273 raw_spin_unlock_irqrestore(&rq->lock, flags); 2274 2275 rq->post_schedule = 0; 2276 } 2277} 2278 2279#else 2280 2281static inline void post_schedule(struct rq *rq) 2282{ 2283} 2284 2285#endif 2286 2287/** 2288 * schedule_tail - first thing a freshly forked thread must call. 2289 * @prev: the thread we just switched away from. 2290 */ 2291asmlinkage __visible void schedule_tail(struct task_struct *prev) 2292 __releases(rq->lock) 2293{ 2294 struct rq *rq = this_rq(); 2295 2296 finish_task_switch(rq, prev); 2297 2298 /* 2299 * FIXME: do we need to worry about rq being invalidated by the 2300 * task_switch? 2301 */ 2302 post_schedule(rq); 2303 2304#ifdef __ARCH_WANT_UNLOCKED_CTXSW 2305 /* In this case, finish_task_switch does not reenable preemption */ 2306 preempt_enable(); 2307#endif 2308 if (current->set_child_tid) 2309 put_user(task_pid_vnr(current), current->set_child_tid); 2310} 2311 2312/* 2313 * context_switch - switch to the new MM and the new 2314 * thread's register state. 2315 */ 2316static inline void 2317context_switch(struct rq *rq, struct task_struct *prev, 2318 struct task_struct *next) 2319{ 2320 struct mm_struct *mm, *oldmm; 2321 2322 prepare_task_switch(rq, prev, next); 2323 2324 mm = next->mm; 2325 oldmm = prev->active_mm; 2326 /* 2327 * For paravirt, this is coupled with an exit in switch_to to 2328 * combine the page table reload and the switch backend into 2329 * one hypercall. 2330 */ 2331 arch_start_context_switch(prev); 2332 2333 if (!mm) { 2334 next->active_mm = oldmm; 2335 atomic_inc(&oldmm->mm_count); 2336 enter_lazy_tlb(oldmm, next); 2337 } else 2338 switch_mm(oldmm, mm, next); 2339 2340 if (!prev->mm) { 2341 prev->active_mm = NULL; 2342 rq->prev_mm = oldmm; 2343 } 2344 /* 2345 * Since the runqueue lock will be released by the next 2346 * task (which is an invalid locking op but in the case 2347 * of the scheduler it's an obvious special-case), so we 2348 * do an early lockdep release here: 2349 */ 2350#ifndef __ARCH_WANT_UNLOCKED_CTXSW 2351 spin_release(&rq->lock.dep_map, 1, _THIS_IP_); 2352#endif 2353 2354 context_tracking_task_switch(prev, next); 2355 /* Here we just switch the register state and the stack. */ 2356 switch_to(prev, next, prev); 2357 2358 barrier(); 2359 /* 2360 * this_rq must be evaluated again because prev may have moved 2361 * CPUs since it called schedule(), thus the 'rq' on its stack 2362 * frame will be invalid. 2363 */ 2364 finish_task_switch(this_rq(), prev); 2365} 2366 2367/* 2368 * nr_running and nr_context_switches: 2369 * 2370 * externally visible scheduler statistics: current number of runnable 2371 * threads, total number of context switches performed since bootup. 2372 */ 2373unsigned long nr_running(void) 2374{ 2375 unsigned long i, sum = 0; 2376 2377 for_each_online_cpu(i) 2378 sum += cpu_rq(i)->nr_running; 2379 2380 return sum; 2381} 2382 2383unsigned long long nr_context_switches(void) 2384{ 2385 int i; 2386 unsigned long long sum = 0; 2387 2388 for_each_possible_cpu(i) 2389 sum += cpu_rq(i)->nr_switches; 2390 2391 return sum; 2392} 2393 2394unsigned long nr_iowait(void) 2395{ 2396 unsigned long i, sum = 0; 2397 2398 for_each_possible_cpu(i) 2399 sum += atomic_read(&cpu_rq(i)->nr_iowait); 2400 2401 return sum; 2402} 2403 2404unsigned long nr_iowait_cpu(int cpu) 2405{ 2406 struct rq *this = cpu_rq(cpu); 2407 return atomic_read(&this->nr_iowait); 2408} 2409 2410void get_iowait_load(unsigned long *nr_waiters, unsigned long *load) 2411{ 2412 struct rq *this = this_rq(); 2413 *nr_waiters = atomic_read(&this->nr_iowait); 2414 *load = this->cpu_load[0]; 2415} 2416 2417#ifdef CONFIG_SMP 2418 2419/* 2420 * sched_exec - execve() is a valuable balancing opportunity, because at 2421 * this point the task has the smallest effective memory and cache footprint. 2422 */ 2423void sched_exec(void) 2424{ 2425 struct task_struct *p = current; 2426 unsigned long flags; 2427 int dest_cpu; 2428 2429 raw_spin_lock_irqsave(&p->pi_lock, flags); 2430 dest_cpu = p->sched_class->select_task_rq(p, task_cpu(p), SD_BALANCE_EXEC, 0); 2431 if (dest_cpu == smp_processor_id()) 2432 goto unlock; 2433 2434 if (likely(cpu_active(dest_cpu))) { 2435 struct migration_arg arg = { p, dest_cpu }; 2436 2437 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 2438 stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg); 2439 return; 2440 } 2441unlock: 2442 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 2443} 2444 2445#endif 2446 2447DEFINE_PER_CPU(struct kernel_stat, kstat); 2448DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat); 2449 2450EXPORT_PER_CPU_SYMBOL(kstat); 2451EXPORT_PER_CPU_SYMBOL(kernel_cpustat); 2452 2453/* 2454 * Return any ns on the sched_clock that have not yet been accounted in 2455 * @p in case that task is currently running. 2456 * 2457 * Called with task_rq_lock() held on @rq. 2458 */ 2459static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq) 2460{ 2461 u64 ns = 0; 2462 2463 /* 2464 * Must be ->curr _and_ ->on_rq. If dequeued, we would 2465 * project cycles that may never be accounted to this 2466 * thread, breaking clock_gettime(). 2467 */ 2468 if (task_current(rq, p) && task_on_rq_queued(p)) { 2469 update_rq_clock(rq); 2470 ns = rq_clock_task(rq) - p->se.exec_start; 2471 if ((s64)ns < 0) 2472 ns = 0; 2473 } 2474 2475 return ns; 2476} 2477 2478unsigned long long task_delta_exec(struct task_struct *p) 2479{ 2480 unsigned long flags; 2481 struct rq *rq; 2482 u64 ns = 0; 2483 2484 rq = task_rq_lock(p, &flags); 2485 ns = do_task_delta_exec(p, rq); 2486 task_rq_unlock(rq, p, &flags); 2487 2488 return ns; 2489} 2490 2491/* 2492 * Return accounted runtime for the task. 2493 * In case the task is currently running, return the runtime plus current's 2494 * pending runtime that have not been accounted yet. 2495 */ 2496unsigned long long task_sched_runtime(struct task_struct *p) 2497{ 2498 unsigned long flags; 2499 struct rq *rq; 2500 u64 ns = 0; 2501 2502#if defined(CONFIG_64BIT) && defined(CONFIG_SMP) 2503 /* 2504 * 64-bit doesn't need locks to atomically read a 64bit value. 2505 * So we have a optimization chance when the task's delta_exec is 0. 2506 * Reading ->on_cpu is racy, but this is ok. 2507 * 2508 * If we race with it leaving cpu, we'll take a lock. So we're correct. 2509 * If we race with it entering cpu, unaccounted time is 0. This is 2510 * indistinguishable from the read occurring a few cycles earlier. 2511 * If we see ->on_cpu without ->on_rq, the task is leaving, and has 2512 * been accounted, so we're correct here as well. 2513 */ 2514 if (!p->on_cpu || !task_on_rq_queued(p)) 2515 return p->se.sum_exec_runtime; 2516#endif 2517 2518 rq = task_rq_lock(p, &flags); 2519 ns = p->se.sum_exec_runtime + do_task_delta_exec(p, rq); 2520 task_rq_unlock(rq, p, &flags); 2521 2522 return ns; 2523} 2524 2525/* 2526 * This function gets called by the timer code, with HZ frequency. 2527 * We call it with interrupts disabled. 2528 */ 2529void scheduler_tick(void) 2530{ 2531 int cpu = smp_processor_id(); 2532 struct rq *rq = cpu_rq(cpu); 2533 struct task_struct *curr = rq->curr; 2534 2535 sched_clock_tick(); 2536 2537 raw_spin_lock(&rq->lock); 2538 update_rq_clock(rq); 2539 curr->sched_class->task_tick(rq, curr, 0); 2540 update_cpu_load_active(rq); 2541 raw_spin_unlock(&rq->lock); 2542 2543 perf_event_task_tick(); 2544 2545#ifdef CONFIG_SMP 2546 rq->idle_balance = idle_cpu(cpu); 2547 trigger_load_balance(rq); 2548#endif 2549 rq_last_tick_reset(rq); 2550} 2551 2552#ifdef CONFIG_NO_HZ_FULL 2553/** 2554 * scheduler_tick_max_deferment 2555 * 2556 * Keep at least one tick per second when a single 2557 * active task is running because the scheduler doesn't 2558 * yet completely support full dynticks environment. 2559 * 2560 * This makes sure that uptime, CFS vruntime, load 2561 * balancing, etc... continue to move forward, even 2562 * with a very low granularity. 2563 * 2564 * Return: Maximum deferment in nanoseconds. 2565 */ 2566u64 scheduler_tick_max_deferment(void) 2567{ 2568 struct rq *rq = this_rq(); 2569 unsigned long next, now = ACCESS_ONCE(jiffies); 2570 2571 next = rq->last_sched_tick + HZ; 2572 2573 if (time_before_eq(next, now)) 2574 return 0; 2575 2576 return jiffies_to_nsecs(next - now); 2577} 2578#endif 2579 2580notrace unsigned long get_parent_ip(unsigned long addr) 2581{ 2582 if (in_lock_functions(addr)) { 2583 addr = CALLER_ADDR2; 2584 if (in_lock_functions(addr)) 2585 addr = CALLER_ADDR3; 2586 } 2587 return addr; 2588} 2589 2590#if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \ 2591 defined(CONFIG_PREEMPT_TRACER)) 2592 2593void preempt_count_add(int val) 2594{ 2595#ifdef CONFIG_DEBUG_PREEMPT 2596 /* 2597 * Underflow? 2598 */ 2599 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) 2600 return; 2601#endif 2602 __preempt_count_add(val); 2603#ifdef CONFIG_DEBUG_PREEMPT 2604 /* 2605 * Spinlock count overflowing soon? 2606 */ 2607 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= 2608 PREEMPT_MASK - 10); 2609#endif 2610 if (preempt_count() == val) { 2611 unsigned long ip = get_parent_ip(CALLER_ADDR1); 2612#ifdef CONFIG_DEBUG_PREEMPT 2613 current->preempt_disable_ip = ip; 2614#endif 2615 trace_preempt_off(CALLER_ADDR0, ip); 2616 } 2617} 2618EXPORT_SYMBOL(preempt_count_add); 2619NOKPROBE_SYMBOL(preempt_count_add); 2620 2621void preempt_count_sub(int val) 2622{ 2623#ifdef CONFIG_DEBUG_PREEMPT 2624 /* 2625 * Underflow? 2626 */ 2627 if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) 2628 return; 2629 /* 2630 * Is the spinlock portion underflowing? 2631 */ 2632 if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && 2633 !(preempt_count() & PREEMPT_MASK))) 2634 return; 2635#endif 2636 2637 if (preempt_count() == val) 2638 trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); 2639 __preempt_count_sub(val); 2640} 2641EXPORT_SYMBOL(preempt_count_sub); 2642NOKPROBE_SYMBOL(preempt_count_sub); 2643 2644#endif 2645 2646/* 2647 * Print scheduling while atomic bug: 2648 */ 2649static noinline void __schedule_bug(struct task_struct *prev) 2650{ 2651 if (oops_in_progress) 2652 return; 2653 2654 printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n", 2655 prev->comm, prev->pid, preempt_count()); 2656 2657 debug_show_held_locks(prev); 2658 print_modules(); 2659 if (irqs_disabled()) 2660 print_irqtrace_events(prev); 2661#ifdef CONFIG_DEBUG_PREEMPT 2662 if (in_atomic_preempt_off()) { 2663 pr_err("Preemption disabled at:"); 2664 print_ip_sym(current->preempt_disable_ip); 2665 pr_cont("\n"); 2666 } 2667#endif 2668 dump_stack(); 2669 add_taint(TAINT_WARN, LOCKDEP_STILL_OK); 2670} 2671 2672/* 2673 * Various schedule()-time debugging checks and statistics: 2674 */ 2675static inline void schedule_debug(struct task_struct *prev) 2676{ 2677 /* 2678 * Test if we are atomic. Since do_exit() needs to call into 2679 * schedule() atomically, we ignore that path. Otherwise whine 2680 * if we are scheduling when we should not. 2681 */ 2682 if (unlikely(in_atomic_preempt_off() && prev->state != TASK_DEAD)) 2683 __schedule_bug(prev); 2684 rcu_sleep_check(); 2685 2686 profile_hit(SCHED_PROFILING, __builtin_return_address(0)); 2687 2688 schedstat_inc(this_rq(), sched_count); 2689} 2690 2691/* 2692 * Pick up the highest-prio task: 2693 */ 2694static inline struct task_struct * 2695pick_next_task(struct rq *rq, struct task_struct *prev) 2696{ 2697 const struct sched_class *class = &fair_sched_class; 2698 struct task_struct *p; 2699 2700 /* 2701 * Optimization: we know that if all tasks are in 2702 * the fair class we can call that function directly: 2703 */ 2704 if (likely(prev->sched_class == class && 2705 rq->nr_running == rq->cfs.h_nr_running)) { 2706 p = fair_sched_class.pick_next_task(rq, prev); 2707 if (unlikely(p == RETRY_TASK)) 2708 goto again; 2709 2710 /* assumes fair_sched_class->next == idle_sched_class */ 2711 if (unlikely(!p)) 2712 p = idle_sched_class.pick_next_task(rq, prev); 2713 2714 return p; 2715 } 2716 2717again: 2718 for_each_class(class) { 2719 p = class->pick_next_task(rq, prev); 2720 if (p) { 2721 if (unlikely(p == RETRY_TASK)) 2722 goto again; 2723 return p; 2724 } 2725 } 2726 2727 BUG(); /* the idle class will always have a runnable task */ 2728} 2729 2730/* 2731 * __schedule() is the main scheduler function. 2732 * 2733 * The main means of driving the scheduler and thus entering this function are: 2734 * 2735 * 1. Explicit blocking: mutex, semaphore, waitqueue, etc. 2736 * 2737 * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return 2738 * paths. For example, see arch/x86/entry_64.S. 2739 * 2740 * To drive preemption between tasks, the scheduler sets the flag in timer 2741 * interrupt handler scheduler_tick(). 2742 * 2743 * 3. Wakeups don't really cause entry into schedule(). They add a 2744 * task to the run-queue and that's it. 2745 * 2746 * Now, if the new task added to the run-queue preempts the current 2747 * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets 2748 * called on the nearest possible occasion: 2749 * 2750 * - If the kernel is preemptible (CONFIG_PREEMPT=y): 2751 * 2752 * - in syscall or exception context, at the next outmost 2753 * preempt_enable(). (this might be as soon as the wake_up()'s 2754 * spin_unlock()!) 2755 * 2756 * - in IRQ context, return from interrupt-handler to 2757 * preemptible context 2758 * 2759 * - If the kernel is not preemptible (CONFIG_PREEMPT is not set) 2760 * then at the next: 2761 * 2762 * - cond_resched() call 2763 * - explicit schedule() call 2764 * - return from syscall or exception to user-space 2765 * - return from interrupt-handler to user-space 2766 */ 2767static void __sched __schedule(void) 2768{ 2769 struct task_struct *prev, *next; 2770 unsigned long *switch_count; 2771 struct rq *rq; 2772 int cpu; 2773 2774need_resched: 2775 preempt_disable(); 2776 cpu = smp_processor_id(); 2777 rq = cpu_rq(cpu); 2778 rcu_note_context_switch(cpu); 2779 prev = rq->curr; 2780 2781 schedule_debug(prev); 2782 2783 if (sched_feat(HRTICK)) 2784 hrtick_clear(rq); 2785 2786 /* 2787 * Make sure that signal_pending_state()->signal_pending() below 2788 * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE) 2789 * done by the caller to avoid the race with signal_wake_up(). 2790 */ 2791 smp_mb__before_spinlock(); 2792 raw_spin_lock_irq(&rq->lock); 2793 2794 switch_count = &prev->nivcsw; 2795 if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { 2796 if (unlikely(signal_pending_state(prev->state, prev))) { 2797 prev->state = TASK_RUNNING; 2798 } else { 2799 deactivate_task(rq, prev, DEQUEUE_SLEEP); 2800 prev->on_rq = 0; 2801 2802 /* 2803 * If a worker went to sleep, notify and ask workqueue 2804 * whether it wants to wake up a task to maintain 2805 * concurrency. 2806 */ 2807 if (prev->flags & PF_WQ_WORKER) { 2808 struct task_struct *to_wakeup; 2809 2810 to_wakeup = wq_worker_sleeping(prev, cpu); 2811 if (to_wakeup) 2812 try_to_wake_up_local(to_wakeup); 2813 } 2814 } 2815 switch_count = &prev->nvcsw; 2816 } 2817 2818 if (task_on_rq_queued(prev) || rq->skip_clock_update < 0) 2819 update_rq_clock(rq); 2820 2821 next = pick_next_task(rq, prev); 2822 clear_tsk_need_resched(prev); 2823 clear_preempt_need_resched(); 2824 rq->skip_clock_update = 0; 2825 2826 if (likely(prev != next)) { 2827 rq->nr_switches++; 2828 rq->curr = next; 2829 ++*switch_count; 2830 2831 context_switch(rq, prev, next); /* unlocks the rq */ 2832 /* 2833 * The context switch have flipped the stack from under us 2834 * and restored the local variables which were saved when 2835 * this task called schedule() in the past. prev == current 2836 * is still correct, but it can be moved to another cpu/rq. 2837 */ 2838 cpu = smp_processor_id(); 2839 rq = cpu_rq(cpu); 2840 } else 2841 raw_spin_unlock_irq(&rq->lock); 2842 2843 post_schedule(rq); 2844 2845 sched_preempt_enable_no_resched(); 2846 if (need_resched()) 2847 goto need_resched; 2848} 2849 2850static inline void sched_submit_work(struct task_struct *tsk) 2851{ 2852 if (!tsk->state || tsk_is_pi_blocked(tsk)) 2853 return; 2854 /* 2855 * If we are going to sleep and we have plugged IO queued, 2856 * make sure to submit it to avoid deadlocks. 2857 */ 2858 if (blk_needs_flush_plug(tsk)) 2859 blk_schedule_flush_plug(tsk); 2860} 2861 2862asmlinkage __visible void __sched schedule(void) 2863{ 2864 struct task_struct *tsk = current; 2865 2866 sched_submit_work(tsk); 2867 __schedule(); 2868} 2869EXPORT_SYMBOL(schedule); 2870 2871#ifdef CONFIG_CONTEXT_TRACKING 2872asmlinkage __visible void __sched schedule_user(void) 2873{ 2874 /* 2875 * If we come here after a random call to set_need_resched(), 2876 * or we have been woken up remotely but the IPI has not yet arrived, 2877 * we haven't yet exited the RCU idle mode. Do it here manually until 2878 * we find a better solution. 2879 */ 2880 user_exit(); 2881 schedule(); 2882 user_enter(); 2883} 2884#endif 2885 2886/** 2887 * schedule_preempt_disabled - called with preemption disabled 2888 * 2889 * Returns with preemption disabled. Note: preempt_count must be 1 2890 */ 2891void __sched schedule_preempt_disabled(void) 2892{ 2893 sched_preempt_enable_no_resched(); 2894 schedule(); 2895 preempt_disable(); 2896} 2897 2898#ifdef CONFIG_PREEMPT 2899/* 2900 * this is the entry point to schedule() from in-kernel preemption 2901 * off of preempt_enable. Kernel preemptions off return from interrupt 2902 * occur there and call schedule directly. 2903 */ 2904asmlinkage __visible void __sched notrace preempt_schedule(void) 2905{ 2906 /* 2907 * If there is a non-zero preempt_count or interrupts are disabled, 2908 * we do not want to preempt the current task. Just return.. 2909 */ 2910 if (likely(!preemptible())) 2911 return; 2912 2913 do { 2914 __preempt_count_add(PREEMPT_ACTIVE); 2915 __schedule(); 2916 __preempt_count_sub(PREEMPT_ACTIVE); 2917 2918 /* 2919 * Check again in case we missed a preemption opportunity 2920 * between schedule and now. 2921 */ 2922 barrier(); 2923 } while (need_resched()); 2924} 2925NOKPROBE_SYMBOL(preempt_schedule); 2926EXPORT_SYMBOL(preempt_schedule); 2927#endif /* CONFIG_PREEMPT */ 2928 2929/* 2930 * this is the entry point to schedule() from kernel preemption 2931 * off of irq context. 2932 * Note, that this is called and return with irqs disabled. This will 2933 * protect us against recursive calling from irq. 2934 */ 2935asmlinkage __visible void __sched preempt_schedule_irq(void) 2936{ 2937 enum ctx_state prev_state; 2938 2939 /* Catch callers which need to be fixed */ 2940 BUG_ON(preempt_count() || !irqs_disabled()); 2941 2942 prev_state = exception_enter(); 2943 2944 do { 2945 __preempt_count_add(PREEMPT_ACTIVE); 2946 local_irq_enable(); 2947 __schedule(); 2948 local_irq_disable(); 2949 __preempt_count_sub(PREEMPT_ACTIVE); 2950 2951 /* 2952 * Check again in case we missed a preemption opportunity 2953 * between schedule and now. 2954 */ 2955 barrier(); 2956 } while (need_resched()); 2957 2958 exception_exit(prev_state); 2959} 2960 2961int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags, 2962 void *key) 2963{ 2964 return try_to_wake_up(curr->private, mode, wake_flags); 2965} 2966EXPORT_SYMBOL(default_wake_function); 2967 2968#ifdef CONFIG_RT_MUTEXES 2969 2970/* 2971 * rt_mutex_setprio - set the current priority of a task 2972 * @p: task 2973 * @prio: prio value (kernel-internal form) 2974 * 2975 * This function changes the 'effective' priority of a task. It does 2976 * not touch ->normal_prio like __setscheduler(). 2977 * 2978 * Used by the rt_mutex code to implement priority inheritance 2979 * logic. Call site only calls if the priority of the task changed. 2980 */ 2981void rt_mutex_setprio(struct task_struct *p, int prio) 2982{ 2983 int oldprio, queued, running, enqueue_flag = 0; 2984 struct rq *rq; 2985 const struct sched_class *prev_class; 2986 2987 BUG_ON(prio > MAX_PRIO); 2988 2989 rq = __task_rq_lock(p); 2990 2991 /* 2992 * Idle task boosting is a nono in general. There is one 2993 * exception, when PREEMPT_RT and NOHZ is active: 2994 * 2995 * The idle task calls get_next_timer_interrupt() and holds 2996 * the timer wheel base->lock on the CPU and another CPU wants 2997 * to access the timer (probably to cancel it). We can safely 2998 * ignore the boosting request, as the idle CPU runs this code 2999 * with interrupts disabled and will complete the lock 3000 * protected section without being interrupted. So there is no 3001 * real need to boost. 3002 */ 3003 if (unlikely(p == rq->idle)) { 3004 WARN_ON(p != rq->curr); 3005 WARN_ON(p->pi_blocked_on); 3006 goto out_unlock; 3007 } 3008 3009 trace_sched_pi_setprio(p, prio); 3010 oldprio = p->prio; 3011 prev_class = p->sched_class; 3012 queued = task_on_rq_queued(p); 3013 running = task_current(rq, p); 3014 if (queued) 3015 dequeue_task(rq, p, 0); 3016 if (running) 3017 p->sched_class->put_prev_task(rq, p); 3018 3019 /* 3020 * Boosting condition are: 3021 * 1. -rt task is running and holds mutex A 3022 * --> -dl task blocks on mutex A 3023 * 3024 * 2. -dl task is running and holds mutex A 3025 * --> -dl task blocks on mutex A and could preempt the 3026 * running task 3027 */ 3028 if (dl_prio(prio)) { 3029 struct task_struct *pi_task = rt_mutex_get_top_task(p); 3030 if (!dl_prio(p->normal_prio) || 3031 (pi_task && dl_entity_preempt(&pi_task->dl, &p->dl))) { 3032 p->dl.dl_boosted = 1; 3033 p->dl.dl_throttled = 0; 3034 enqueue_flag = ENQUEUE_REPLENISH; 3035 } else 3036 p->dl.dl_boosted = 0; 3037 p->sched_class = &dl_sched_class; 3038 } else if (rt_prio(prio)) { 3039 if (dl_prio(oldprio)) 3040 p->dl.dl_boosted = 0; 3041 if (oldprio < prio) 3042 enqueue_flag = ENQUEUE_HEAD; 3043 p->sched_class = &rt_sched_class; 3044 } else { 3045 if (dl_prio(oldprio)) 3046 p->dl.dl_boosted = 0; 3047 p->sched_class = &fair_sched_class; 3048 } 3049 3050 p->prio = prio; 3051 3052 if (running) 3053 p->sched_class->set_curr_task(rq); 3054 if (queued) 3055 enqueue_task(rq, p, enqueue_flag); 3056 3057 check_class_changed(rq, p, prev_class, oldprio); 3058out_unlock: 3059 __task_rq_unlock(rq); 3060} 3061#endif 3062 3063void set_user_nice(struct task_struct *p, long nice) 3064{ 3065 int old_prio, delta, queued; 3066 unsigned long flags; 3067 struct rq *rq; 3068 3069 if (task_nice(p) == nice || nice < MIN_NICE || nice > MAX_NICE) 3070 return; 3071 /* 3072 * We have to be careful, if called from sys_setpriority(), 3073 * the task might be in the middle of scheduling on another CPU. 3074 */ 3075 rq = task_rq_lock(p, &flags); 3076 /* 3077 * The RT priorities are set via sched_setscheduler(), but we still 3078 * allow the 'normal' nice value to be set - but as expected 3079 * it wont have any effect on scheduling until the task is 3080 * SCHED_DEADLINE, SCHED_FIFO or SCHED_RR: 3081 */ 3082 if (task_has_dl_policy(p) || task_has_rt_policy(p)) { 3083 p->static_prio = NICE_TO_PRIO(nice); 3084 goto out_unlock; 3085 } 3086 queued = task_on_rq_queued(p); 3087 if (queued) 3088 dequeue_task(rq, p, 0); 3089 3090 p->static_prio = NICE_TO_PRIO(nice); 3091 set_load_weight(p); 3092 old_prio = p->prio; 3093 p->prio = effective_prio(p); 3094 delta = p->prio - old_prio; 3095 3096 if (queued) { 3097 enqueue_task(rq, p, 0); 3098 /* 3099 * If the task increased its priority or is running and 3100 * lowered its priority, then reschedule its CPU: 3101 */ 3102 if (delta < 0 || (delta > 0 && task_running(rq, p))) 3103 resched_curr(rq); 3104 } 3105out_unlock: 3106 task_rq_unlock(rq, p, &flags); 3107} 3108EXPORT_SYMBOL(set_user_nice); 3109 3110/* 3111 * can_nice - check if a task can reduce its nice value 3112 * @p: task 3113 * @nice: nice value 3114 */ 3115int can_nice(const struct task_struct *p, const int nice) 3116{ 3117 /* convert nice value [19,-20] to rlimit style value [1,40] */ 3118 int nice_rlim = nice_to_rlimit(nice); 3119 3120 return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) || 3121 capable(CAP_SYS_NICE)); 3122} 3123 3124#ifdef __ARCH_WANT_SYS_NICE 3125 3126/* 3127 * sys_nice - change the priority of the current process. 3128 * @increment: priority increment 3129 * 3130 * sys_setpriority is a more generic, but much slower function that 3131 * does similar things. 3132 */ 3133SYSCALL_DEFINE1(nice, int, increment) 3134{ 3135 long nice, retval; 3136 3137 /* 3138 * Setpriority might change our priority at the same moment. 3139 * We don't have to worry. Conceptually one call occurs first 3140 * and we have a single winner. 3141 */ 3142 increment = clamp(increment, -NICE_WIDTH, NICE_WIDTH); 3143 nice = task_nice(current) + increment; 3144 3145 nice = clamp_val(nice, MIN_NICE, MAX_NICE); 3146 if (increment < 0 && !can_nice(current, nice)) 3147 return -EPERM; 3148 3149 retval = security_task_setnice(current, nice); 3150 if (retval) 3151 return retval; 3152 3153 set_user_nice(current, nice); 3154 return 0; 3155} 3156 3157#endif 3158 3159/** 3160 * task_prio - return the priority value of a given task. 3161 * @p: the task in question. 3162 * 3163 * Return: The priority value as seen by users in /proc. 3164 * RT tasks are offset by -200. Normal tasks are centered 3165 * around 0, value goes from -16 to +15. 3166 */ 3167int task_prio(const struct task_struct *p) 3168{ 3169 return p->prio - MAX_RT_PRIO; 3170} 3171 3172/** 3173 * idle_cpu - is a given cpu idle currently? 3174 * @cpu: the processor in question. 3175 * 3176 * Return: 1 if the CPU is currently idle. 0 otherwise. 3177 */ 3178int idle_cpu(int cpu) 3179{ 3180 struct rq *rq = cpu_rq(cpu); 3181 3182 if (rq->curr != rq->idle) 3183 return 0; 3184 3185 if (rq->nr_running) 3186 return 0; 3187 3188#ifdef CONFIG_SMP 3189 if (!llist_empty(&rq->wake_list)) 3190 return 0; 3191#endif 3192 3193 return 1; 3194} 3195 3196/** 3197 * idle_task - return the idle task for a given cpu. 3198 * @cpu: the processor in question. 3199 * 3200 * Return: The idle task for the cpu @cpu. 3201 */ 3202struct task_struct *idle_task(int cpu) 3203{ 3204 return cpu_rq(cpu)->idle; 3205} 3206 3207/** 3208 * find_process_by_pid - find a process with a matching PID value. 3209 * @pid: the pid in question. 3210 * 3211 * The task of @pid, if found. %NULL otherwise. 3212 */ 3213static struct task_struct *find_process_by_pid(pid_t pid) 3214{ 3215 return pid ? find_task_by_vpid(pid) : current; 3216} 3217 3218/* 3219 * This function initializes the sched_dl_entity of a newly becoming 3220 * SCHED_DEADLINE task. 3221 * 3222 * Only the static values are considered here, the actual runtime and the 3223 * absolute deadline will be properly calculated when the task is enqueued 3224 * for the first time with its new policy. 3225 */ 3226static void 3227__setparam_dl(struct task_struct *p, const struct sched_attr *attr) 3228{ 3229 struct sched_dl_entity *dl_se = &p->dl; 3230 3231 init_dl_task_timer(dl_se); 3232 dl_se->dl_runtime = attr->sched_runtime; 3233 dl_se->dl_deadline = attr->sched_deadline; 3234 dl_se->dl_period = attr->sched_period ?: dl_se->dl_deadline; 3235 dl_se->flags = attr->sched_flags; 3236 dl_se->dl_bw = to_ratio(dl_se->dl_period, dl_se->dl_runtime); 3237 dl_se->dl_throttled = 0; 3238 dl_se->dl_new = 1; 3239 dl_se->dl_yielded = 0; 3240} 3241 3242/* 3243 * sched_setparam() passes in -1 for its policy, to let the functions 3244 * it calls know not to change it. 3245 */ 3246#define SETPARAM_POLICY -1 3247 3248static void __setscheduler_params(struct task_struct *p, 3249 const struct sched_attr *attr) 3250{ 3251 int policy = attr->sched_policy; 3252 3253 if (policy == SETPARAM_POLICY) 3254 policy = p->policy; 3255 3256 p->policy = policy; 3257 3258 if (dl_policy(policy)) 3259 __setparam_dl(p, attr); 3260 else if (fair_policy(policy)) 3261 p->static_prio = NICE_TO_PRIO(attr->sched_nice); 3262 3263 /* 3264 * __sched_setscheduler() ensures attr->sched_priority == 0 when 3265 * !rt_policy. Always setting this ensures that things like 3266 * getparam()/getattr() don't report silly values for !rt tasks. 3267 */ 3268 p->rt_priority = attr->sched_priority; 3269 p->normal_prio = normal_prio(p); 3270 set_load_weight(p); 3271} 3272 3273/* Actually do priority change: must hold pi & rq lock. */ 3274static void __setscheduler(struct rq *rq, struct task_struct *p, 3275 const struct sched_attr *attr) 3276{ 3277 __setscheduler_params(p, attr); 3278 3279 /* 3280 * If we get here, there was no pi waiters boosting the 3281 * task. It is safe to use the normal prio. 3282 */ 3283 p->prio = normal_prio(p); 3284 3285 if (dl_prio(p->prio)) 3286 p->sched_class = &dl_sched_class; 3287 else if (rt_prio(p->prio)) 3288 p->sched_class = &rt_sched_class; 3289 else 3290 p->sched_class = &fair_sched_class; 3291} 3292 3293static void 3294__getparam_dl(struct task_struct *p, struct sched_attr *attr) 3295{ 3296 struct sched_dl_entity *dl_se = &p->dl; 3297 3298 attr->sched_priority = p->rt_priority; 3299 attr->sched_runtime = dl_se->dl_runtime; 3300 attr->sched_deadline = dl_se->dl_deadline; 3301 attr->sched_period = dl_se->dl_period; 3302 attr->sched_flags = dl_se->flags; 3303} 3304 3305/* 3306 * This function validates the new parameters of a -deadline task. 3307 * We ask for the deadline not being zero, and greater or equal 3308 * than the runtime, as well as the period of being zero or 3309 * greater than deadline. Furthermore, we have to be sure that 3310 * user parameters are above the internal resolution of 1us (we 3311 * check sched_runtime only since it is always the smaller one) and 3312 * below 2^63 ns (we have to check both sched_deadline and 3313 * sched_period, as the latter can be zero). 3314 */ 3315static bool 3316__checkparam_dl(const struct sched_attr *attr) 3317{ 3318 /* deadline != 0 */ 3319 if (attr->sched_deadline == 0) 3320 return false; 3321 3322 /* 3323 * Since we truncate DL_SCALE bits, make sure we're at least 3324 * that big. 3325 */ 3326 if (attr->sched_runtime < (1ULL << DL_SCALE)) 3327 return false; 3328 3329 /* 3330 * Since we use the MSB for wrap-around and sign issues, make 3331 * sure it's not set (mind that period can be equal to zero). 3332 */ 3333 if (attr->sched_deadline & (1ULL << 63) || 3334 attr->sched_period & (1ULL << 63)) 3335 return false; 3336 3337 /* runtime <= deadline <= period (if period != 0) */ 3338 if ((attr->sched_period != 0 && 3339 attr->sched_period < attr->sched_deadline) || 3340 attr->sched_deadline < attr->sched_runtime) 3341 return false; 3342 3343 return true; 3344} 3345 3346/* 3347 * check the target process has a UID that matches the current process's 3348 */ 3349static bool check_same_owner(struct task_struct *p) 3350{ 3351 const struct cred *cred = current_cred(), *pcred; 3352 bool match; 3353 3354 rcu_read_lock(); 3355 pcred = __task_cred(p); 3356 match = (uid_eq(cred->euid, pcred->euid) || 3357 uid_eq(cred->euid, pcred->uid)); 3358 rcu_read_unlock(); 3359 return match; 3360} 3361 3362static int __sched_setscheduler(struct task_struct *p, 3363 const struct sched_attr *attr, 3364 bool user) 3365{ 3366 int newprio = dl_policy(attr->sched_policy) ? MAX_DL_PRIO - 1 : 3367 MAX_RT_PRIO - 1 - attr->sched_priority; 3368 int retval, oldprio, oldpolicy = -1, queued, running; 3369 int policy = attr->sched_policy; 3370 unsigned long flags; 3371 const struct sched_class *prev_class; 3372 struct rq *rq; 3373 int reset_on_fork; 3374 3375 /* may grab non-irq protected spin_locks */ 3376 BUG_ON(in_interrupt()); 3377recheck: 3378 /* double check policy once rq lock held */ 3379 if (policy < 0) { 3380 reset_on_fork = p->sched_reset_on_fork; 3381 policy = oldpolicy = p->policy; 3382 } else { 3383 reset_on_fork = !!(attr->sched_flags & SCHED_FLAG_RESET_ON_FORK); 3384 3385 if (policy != SCHED_DEADLINE && 3386 policy != SCHED_FIFO && policy != SCHED_RR && 3387 policy != SCHED_NORMAL && policy != SCHED_BATCH && 3388 policy != SCHED_IDLE) 3389 return -EINVAL; 3390 } 3391 3392 if (attr->sched_flags & ~(SCHED_FLAG_RESET_ON_FORK)) 3393 return -EINVAL; 3394 3395 /* 3396 * Valid priorities for SCHED_FIFO and SCHED_RR are 3397 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL, 3398 * SCHED_BATCH and SCHED_IDLE is 0. 3399 */ 3400 if ((p->mm && attr->sched_priority > MAX_USER_RT_PRIO-1) || 3401 (!p->mm && attr->sched_priority > MAX_RT_PRIO-1)) 3402 return -EINVAL; 3403 if ((dl_policy(policy) && !__checkparam_dl(attr)) || 3404 (rt_policy(policy) != (attr->sched_priority != 0))) 3405 return -EINVAL; 3406 3407 /* 3408 * Allow unprivileged RT tasks to decrease priority: 3409 */ 3410 if (user && !capable(CAP_SYS_NICE)) { 3411 if (fair_policy(policy)) { 3412 if (attr->sched_nice < task_nice(p) && 3413 !can_nice(p, attr->sched_nice)) 3414 return -EPERM; 3415 } 3416 3417 if (rt_policy(policy)) { 3418 unsigned long rlim_rtprio = 3419 task_rlimit(p, RLIMIT_RTPRIO); 3420 3421 /* can't set/change the rt policy */ 3422 if (policy != p->policy && !rlim_rtprio) 3423 return -EPERM; 3424 3425 /* can't increase priority */ 3426 if (attr->sched_priority > p->rt_priority && 3427 attr->sched_priority > rlim_rtprio) 3428 return -EPERM; 3429 } 3430 3431 /* 3432 * Can't set/change SCHED_DEADLINE policy at all for now 3433 * (safest behavior); in the future we would like to allow 3434 * unprivileged DL tasks to increase their relative deadline 3435 * or reduce their runtime (both ways reducing utilization) 3436 */ 3437 if (dl_policy(policy)) 3438 return -EPERM; 3439 3440 /* 3441 * Treat SCHED_IDLE as nice 20. Only allow a switch to 3442 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it. 3443 */ 3444 if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) { 3445 if (!can_nice(p, task_nice(p))) 3446 return -EPERM; 3447 } 3448 3449 /* can't change other user's priorities */ 3450 if (!check_same_owner(p)) 3451 return -EPERM; 3452 3453 /* Normal users shall not reset the sched_reset_on_fork flag */ 3454 if (p->sched_reset_on_fork && !reset_on_fork) 3455 return -EPERM; 3456 } 3457 3458 if (user) { 3459 retval = security_task_setscheduler(p); 3460 if (retval) 3461 return retval; 3462 } 3463 3464 /* 3465 * make sure no PI-waiters arrive (or leave) while we are 3466 * changing the priority of the task: 3467 * 3468 * To be able to change p->policy safely, the appropriate 3469 * runqueue lock must be held. 3470 */ 3471 rq = task_rq_lock(p, &flags); 3472 3473 /* 3474 * Changing the policy of the stop threads its a very bad idea 3475 */ 3476 if (p == rq->stop) { 3477 task_rq_unlock(rq, p, &flags); 3478 return -EINVAL; 3479 } 3480 3481 /* 3482 * If not changing anything there's no need to proceed further, 3483 * but store a possible modification of reset_on_fork. 3484 */ 3485 if (unlikely(policy == p->policy)) { 3486 if (fair_policy(policy) && attr->sched_nice != task_nice(p)) 3487 goto change; 3488 if (rt_policy(policy) && attr->sched_priority != p->rt_priority) 3489 goto change; 3490 if (dl_policy(policy)) 3491 goto change; 3492 3493 p->sched_reset_on_fork = reset_on_fork; 3494 task_rq_unlock(rq, p, &flags); 3495 return 0; 3496 } 3497change: 3498 3499 if (user) { 3500#ifdef CONFIG_RT_GROUP_SCHED 3501 /* 3502 * Do not allow realtime tasks into groups that have no runtime 3503 * assigned. 3504 */ 3505 if (rt_bandwidth_enabled() && rt_policy(policy) && 3506 task_group(p)->rt_bandwidth.rt_runtime == 0 && 3507 !task_group_is_autogroup(task_group(p))) { 3508 task_rq_unlock(rq, p, &flags); 3509 return -EPERM; 3510 } 3511#endif 3512#ifdef CONFIG_SMP 3513 if (dl_bandwidth_enabled() && dl_policy(policy)) { 3514 cpumask_t *span = rq->rd->span; 3515 3516 /* 3517 * Don't allow tasks with an affinity mask smaller than 3518 * the entire root_domain to become SCHED_DEADLINE. We 3519 * will also fail if there's no bandwidth available. 3520 */ 3521 if (!cpumask_subset(span, &p->cpus_allowed) || 3522 rq->rd->dl_bw.bw == 0) { 3523 task_rq_unlock(rq, p, &flags); 3524 return -EPERM; 3525 } 3526 } 3527#endif 3528 } 3529 3530 /* recheck policy now with rq lock held */ 3531 if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { 3532 policy = oldpolicy = -1; 3533 task_rq_unlock(rq, p, &flags); 3534 goto recheck; 3535 } 3536 3537 /* 3538 * If setscheduling to SCHED_DEADLINE (or changing the parameters 3539 * of a SCHED_DEADLINE task) we need to check if enough bandwidth 3540 * is available. 3541 */ 3542 if ((dl_policy(policy) || dl_task(p)) && dl_overflow(p, policy, attr)) { 3543 task_rq_unlock(rq, p, &flags); 3544 return -EBUSY; 3545 } 3546 3547 p->sched_reset_on_fork = reset_on_fork; 3548 oldprio = p->prio; 3549 3550 /* 3551 * Special case for priority boosted tasks. 3552 * 3553 * If the new priority is lower or equal (user space view) 3554 * than the current (boosted) priority, we just store the new 3555 * normal parameters and do not touch the scheduler class and 3556 * the runqueue. This will be done when the task deboost 3557 * itself. 3558 */ 3559 if (rt_mutex_check_prio(p, newprio)) { 3560 __setscheduler_params(p, attr); 3561 task_rq_unlock(rq, p, &flags); 3562 return 0; 3563 } 3564 3565 queued = task_on_rq_queued(p); 3566 running = task_current(rq, p); 3567 if (queued) 3568 dequeue_task(rq, p, 0); 3569 if (running) 3570 p->sched_class->put_prev_task(rq, p); 3571 3572 prev_class = p->sched_class; 3573 __setscheduler(rq, p, attr); 3574 3575 if (running) 3576 p->sched_class->set_curr_task(rq); 3577 if (queued) { 3578 /* 3579 * We enqueue to tail when the priority of a task is 3580 * increased (user space view). 3581 */ 3582 enqueue_task(rq, p, oldprio <= p->prio ? ENQUEUE_HEAD : 0); 3583 } 3584 3585 check_class_changed(rq, p, prev_class, oldprio); 3586 task_rq_unlock(rq, p, &flags); 3587 3588 rt_mutex_adjust_pi(p); 3589 3590 return 0; 3591} 3592 3593static int _sched_setscheduler(struct task_struct *p, int policy, 3594 const struct sched_param *param, bool check) 3595{ 3596 struct sched_attr attr = { 3597 .sched_policy = policy, 3598 .sched_priority = param->sched_priority, 3599 .sched_nice = PRIO_TO_NICE(p->static_prio), 3600 }; 3601 3602 /* Fixup the legacy SCHED_RESET_ON_FORK hack. */ 3603 if ((policy != SETPARAM_POLICY) && (policy & SCHED_RESET_ON_FORK)) { 3604 attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK; 3605 policy &= ~SCHED_RESET_ON_FORK; 3606 attr.sched_policy = policy; 3607 } 3608 3609 return __sched_setscheduler(p, &attr, check); 3610} 3611/** 3612 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. 3613 * @p: the task in question. 3614 * @policy: new policy. 3615 * @param: structure containing the new RT priority. 3616 * 3617 * Return: 0 on success. An error code otherwise. 3618 * 3619 * NOTE that the task may be already dead. 3620 */ 3621int sched_setscheduler(struct task_struct *p, int policy, 3622 const struct sched_param *param) 3623{ 3624 return _sched_setscheduler(p, policy, param, true); 3625} 3626EXPORT_SYMBOL_GPL(sched_setscheduler); 3627 3628int sched_setattr(struct task_struct *p, const struct sched_attr *attr) 3629{ 3630 return __sched_setscheduler(p, attr, true); 3631} 3632EXPORT_SYMBOL_GPL(sched_setattr); 3633 3634/** 3635 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace. 3636 * @p: the task in question. 3637 * @policy: new policy. 3638 * @param: structure containing the new RT priority. 3639 * 3640 * Just like sched_setscheduler, only don't bother checking if the 3641 * current context has permission. For example, this is needed in 3642 * stop_machine(): we create temporary high priority worker threads, 3643 * but our caller might not have that capability. 3644 * 3645 * Return: 0 on success. An error code otherwise. 3646 */ 3647int sched_setscheduler_nocheck(struct task_struct *p, int policy, 3648 const struct sched_param *param) 3649{ 3650 return _sched_setscheduler(p, policy, param, false); 3651} 3652 3653static int 3654do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) 3655{ 3656 struct sched_param lparam; 3657 struct task_struct *p; 3658 int retval; 3659 3660 if (!param || pid < 0) 3661 return -EINVAL; 3662 if (copy_from_user(&lparam, param, sizeof(struct sched_param))) 3663 return -EFAULT; 3664 3665 rcu_read_lock(); 3666 retval = -ESRCH; 3667 p = find_process_by_pid(pid); 3668 if (p != NULL) 3669 retval = sched_setscheduler(p, policy, &lparam); 3670 rcu_read_unlock(); 3671 3672 return retval; 3673} 3674 3675/* 3676 * Mimics kernel/events/core.c perf_copy_attr(). 3677 */ 3678static int sched_copy_attr(struct sched_attr __user *uattr, 3679 struct sched_attr *attr) 3680{ 3681 u32 size; 3682 int ret; 3683 3684 if (!access_ok(VERIFY_WRITE, uattr, SCHED_ATTR_SIZE_VER0)) 3685 return -EFAULT; 3686 3687 /* 3688 * zero the full structure, so that a short copy will be nice. 3689 */ 3690 memset(attr, 0, sizeof(*attr)); 3691 3692 ret = get_user(size, &uattr->size); 3693 if (ret) 3694 return ret; 3695 3696 if (size > PAGE_SIZE) /* silly large */ 3697 goto err_size; 3698 3699 if (!size) /* abi compat */ 3700 size = SCHED_ATTR_SIZE_VER0; 3701 3702 if (size < SCHED_ATTR_SIZE_VER0) 3703 goto err_size; 3704 3705 /* 3706 * If we're handed a bigger struct than we know of, 3707 * ensure all the unknown bits are 0 - i.e. new 3708 * user-space does not rely on any kernel feature 3709 * extensions we dont know about yet. 3710 */ 3711 if (size > sizeof(*attr)) { 3712 unsigned char __user *addr; 3713 unsigned char __user *end; 3714 unsigned char val; 3715 3716 addr = (void __user *)uattr + sizeof(*attr); 3717 end = (void __user *)uattr + size; 3718 3719 for (; addr < end; addr++) { 3720 ret = get_user(val, addr); 3721 if (ret) 3722 return ret; 3723 if (val) 3724 goto err_size; 3725 } 3726 size = sizeof(*attr); 3727 } 3728 3729 ret = copy_from_user(attr, uattr, size); 3730 if (ret) 3731 return -EFAULT; 3732 3733 /* 3734 * XXX: do we want to be lenient like existing syscalls; or do we want 3735 * to be strict and return an error on out-of-bounds values? 3736 */ 3737 attr->sched_nice = clamp(attr->sched_nice, MIN_NICE, MAX_NICE); 3738 3739 return 0; 3740 3741err_size: 3742 put_user(sizeof(*attr), &uattr->size); 3743 return -E2BIG; 3744} 3745 3746/** 3747 * sys_sched_setscheduler - set/change the scheduler policy and RT priority 3748 * @pid: the pid in question. 3749 * @policy: new policy. 3750 * @param: structure containing the new RT priority. 3751 * 3752 * Return: 0 on success. An error code otherwise. 3753 */ 3754SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy, 3755 struct sched_param __user *, param) 3756{ 3757 /* negative values for policy are not valid */ 3758 if (policy < 0) 3759 return -EINVAL; 3760 3761 return do_sched_setscheduler(pid, policy, param); 3762} 3763 3764/** 3765 * sys_sched_setparam - set/change the RT priority of a thread 3766 * @pid: the pid in question. 3767 * @param: structure containing the new RT priority. 3768 * 3769 * Return: 0 on success. An error code otherwise. 3770 */ 3771SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param) 3772{ 3773 return do_sched_setscheduler(pid, SETPARAM_POLICY, param); 3774} 3775 3776/** 3777 * sys_sched_setattr - same as above, but with extended sched_attr 3778 * @pid: the pid in question. 3779 * @uattr: structure containing the extended parameters. 3780 * @flags: for future extension. 3781 */ 3782SYSCALL_DEFINE3(sched_setattr, pid_t, pid, struct sched_attr __user *, uattr, 3783 unsigned int, flags) 3784{ 3785 struct sched_attr attr; 3786 struct task_struct *p; 3787 int retval; 3788 3789 if (!uattr || pid < 0 || flags) 3790 return -EINVAL; 3791 3792 retval = sched_copy_attr(uattr, &attr); 3793 if (retval) 3794 return retval; 3795 3796 if ((int)attr.sched_policy < 0) 3797 return -EINVAL; 3798 3799 rcu_read_lock(); 3800 retval = -ESRCH; 3801 p = find_process_by_pid(pid); 3802 if (p != NULL) 3803 retval = sched_setattr(p, &attr); 3804 rcu_read_unlock(); 3805 3806 return retval; 3807} 3808 3809/** 3810 * sys_sched_getscheduler - get the policy (scheduling class) of a thread 3811 * @pid: the pid in question. 3812 * 3813 * Return: On success, the policy of the thread. Otherwise, a negative error 3814 * code. 3815 */ 3816SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid) 3817{ 3818 struct task_struct *p; 3819 int retval; 3820 3821 if (pid < 0) 3822 return -EINVAL; 3823 3824 retval = -ESRCH; 3825 rcu_read_lock(); 3826 p = find_process_by_pid(pid); 3827 if (p) { 3828 retval = security_task_getscheduler(p); 3829 if (!retval) 3830 retval = p->policy 3831 | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0); 3832 } 3833 rcu_read_unlock(); 3834 return retval; 3835} 3836 3837/** 3838 * sys_sched_getparam - get the RT priority of a thread 3839 * @pid: the pid in question. 3840 * @param: structure containing the RT priority. 3841 * 3842 * Return: On success, 0 and the RT priority is in @param. Otherwise, an error 3843 * code. 3844 */ 3845SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param) 3846{ 3847 struct sched_param lp = { .sched_priority = 0 }; 3848 struct task_struct *p; 3849 int retval; 3850 3851 if (!param || pid < 0) 3852 return -EINVAL; 3853 3854 rcu_read_lock(); 3855 p = find_process_by_pid(pid); 3856 retval = -ESRCH; 3857 if (!p) 3858 goto out_unlock; 3859 3860 retval = security_task_getscheduler(p); 3861 if (retval) 3862 goto out_unlock; 3863 3864 if (task_has_rt_policy(p)) 3865 lp.sched_priority = p->rt_priority; 3866 rcu_read_unlock(); 3867 3868 /* 3869 * This one might sleep, we cannot do it with a spinlock held ... 3870 */ 3871 retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; 3872 3873 return retval; 3874 3875out_unlock: 3876 rcu_read_unlock(); 3877 return retval; 3878} 3879 3880static int sched_read_attr(struct sched_attr __user *uattr, 3881 struct sched_attr *attr, 3882 unsigned int usize) 3883{ 3884 int ret; 3885 3886 if (!access_ok(VERIFY_WRITE, uattr, usize)) 3887 return -EFAULT; 3888 3889 /* 3890 * If we're handed a smaller struct than we know of, 3891 * ensure all the unknown bits are 0 - i.e. old 3892 * user-space does not get uncomplete information. 3893 */ 3894 if (usize < sizeof(*attr)) { 3895 unsigned char *addr; 3896 unsigned char *end; 3897 3898 addr = (void *)attr + usize; 3899 end = (void *)attr + sizeof(*attr); 3900 3901 for (; addr < end; addr++) { 3902 if (*addr) 3903 return -EFBIG; 3904 } 3905 3906 attr->size = usize; 3907 } 3908 3909 ret = copy_to_user(uattr, attr, attr->size); 3910 if (ret) 3911 return -EFAULT; 3912 3913 return 0; 3914} 3915 3916/** 3917 * sys_sched_getattr - similar to sched_getparam, but with sched_attr 3918 * @pid: the pid in question. 3919 * @uattr: structure containing the extended parameters. 3920 * @size: sizeof(attr) for fwd/bwd comp. 3921 * @flags: for future extension. 3922 */ 3923SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr, 3924 unsigned int, size, unsigned int, flags) 3925{ 3926 struct sched_attr attr = { 3927 .size = sizeof(struct sched_attr), 3928 }; 3929 struct task_struct *p; 3930 int retval; 3931 3932 if (!uattr || pid < 0 || size > PAGE_SIZE || 3933 size < SCHED_ATTR_SIZE_VER0 || flags) 3934 return -EINVAL; 3935 3936 rcu_read_lock(); 3937 p = find_process_by_pid(pid); 3938 retval = -ESRCH; 3939 if (!p) 3940 goto out_unlock; 3941 3942 retval = security_task_getscheduler(p); 3943 if (retval) 3944 goto out_unlock; 3945 3946 attr.sched_policy = p->policy; 3947 if (p->sched_reset_on_fork) 3948 attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK; 3949 if (task_has_dl_policy(p)) 3950 __getparam_dl(p, &attr); 3951 else if (task_has_rt_policy(p)) 3952 attr.sched_priority = p->rt_priority; 3953 else 3954 attr.sched_nice = task_nice(p); 3955 3956 rcu_read_unlock(); 3957 3958 retval = sched_read_attr(uattr, &attr, size); 3959 return retval; 3960 3961out_unlock: 3962 rcu_read_unlock(); 3963 return retval; 3964} 3965 3966long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) 3967{ 3968 cpumask_var_t cpus_allowed, new_mask; 3969 struct task_struct *p; 3970 int retval; 3971 3972 rcu_read_lock(); 3973 3974 p = find_process_by_pid(pid); 3975 if (!p) { 3976 rcu_read_unlock(); 3977 return -ESRCH; 3978 } 3979 3980 /* Prevent p going away */ 3981 get_task_struct(p); 3982 rcu_read_unlock(); 3983 3984 if (p->flags & PF_NO_SETAFFINITY) { 3985 retval = -EINVAL; 3986 goto out_put_task; 3987 } 3988 if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) { 3989 retval = -ENOMEM; 3990 goto out_put_task; 3991 } 3992 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) { 3993 retval = -ENOMEM; 3994 goto out_free_cpus_allowed; 3995 } 3996 retval = -EPERM; 3997 if (!check_same_owner(p)) { 3998 rcu_read_lock(); 3999 if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) { 4000 rcu_read_unlock(); 4001 goto out_unlock; 4002 } 4003 rcu_read_unlock(); 4004 } 4005 4006 retval = security_task_setscheduler(p); 4007 if (retval) 4008 goto out_unlock; 4009 4010 4011 cpuset_cpus_allowed(p, cpus_allowed); 4012 cpumask_and(new_mask, in_mask, cpus_allowed); 4013 4014 /* 4015 * Since bandwidth control happens on root_domain basis, 4016 * if admission test is enabled, we only admit -deadline 4017 * tasks allowed to run on all the CPUs in the task's 4018 * root_domain. 4019 */ 4020#ifdef CONFIG_SMP 4021 if (task_has_dl_policy(p)) { 4022 const struct cpumask *span = task_rq(p)->rd->span; 4023 4024 if (dl_bandwidth_enabled() && !cpumask_subset(span, new_mask)) { 4025 retval = -EBUSY; 4026 goto out_unlock; 4027 } 4028 } 4029#endif 4030again: 4031 retval = set_cpus_allowed_ptr(p, new_mask); 4032 4033 if (!retval) { 4034 cpuset_cpus_allowed(p, cpus_allowed); 4035 if (!cpumask_subset(new_mask, cpus_allowed)) { 4036 /* 4037 * We must have raced with a concurrent cpuset 4038 * update. Just reset the cpus_allowed to the 4039 * cpuset's cpus_allowed 4040 */ 4041 cpumask_copy(new_mask, cpus_allowed); 4042 goto again; 4043 } 4044 } 4045out_unlock: 4046 free_cpumask_var(new_mask); 4047out_free_cpus_allowed: 4048 free_cpumask_var(cpus_allowed); 4049out_put_task: 4050 put_task_struct(p); 4051 return retval; 4052} 4053 4054static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, 4055 struct cpumask *new_mask) 4056{ 4057 if (len < cpumask_size()) 4058 cpumask_clear(new_mask); 4059 else if (len > cpumask_size()) 4060 len = cpumask_size(); 4061 4062 return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; 4063} 4064 4065/** 4066 * sys_sched_setaffinity - set the cpu affinity of a process 4067 * @pid: pid of the process 4068 * @len: length in bytes of the bitmask pointed to by user_mask_ptr 4069 * @user_mask_ptr: user-space pointer to the new cpu mask 4070 * 4071 * Return: 0 on success. An error code otherwise. 4072 */ 4073SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len, 4074 unsigned long __user *, user_mask_ptr) 4075{ 4076 cpumask_var_t new_mask; 4077 int retval; 4078 4079 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) 4080 return -ENOMEM; 4081 4082 retval = get_user_cpu_mask(user_mask_ptr, len, new_mask); 4083 if (retval == 0) 4084 retval = sched_setaffinity(pid, new_mask); 4085 free_cpumask_var(new_mask); 4086 return retval; 4087} 4088 4089long sched_getaffinity(pid_t pid, struct cpumask *mask) 4090{ 4091 struct task_struct *p; 4092 unsigned long flags; 4093 int retval; 4094 4095 rcu_read_lock(); 4096 4097 retval = -ESRCH; 4098 p = find_process_by_pid(pid); 4099 if (!p) 4100 goto out_unlock; 4101 4102 retval = security_task_getscheduler(p); 4103 if (retval) 4104 goto out_unlock; 4105 4106 raw_spin_lock_irqsave(&p->pi_lock, flags); 4107 cpumask_and(mask, &p->cpus_allowed, cpu_active_mask); 4108 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 4109 4110out_unlock: 4111 rcu_read_unlock(); 4112 4113 return retval; 4114} 4115 4116/** 4117 * sys_sched_getaffinity - get the cpu affinity of a process 4118 * @pid: pid of the process 4119 * @len: length in bytes of the bitmask pointed to by user_mask_ptr 4120 * @user_mask_ptr: user-space pointer to hold the current cpu mask 4121 * 4122 * Return: 0 on success. An error code otherwise. 4123 */ 4124SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len, 4125 unsigned long __user *, user_mask_ptr) 4126{ 4127 int ret; 4128 cpumask_var_t mask; 4129 4130 if ((len * BITS_PER_BYTE) < nr_cpu_ids) 4131 return -EINVAL; 4132 if (len & (sizeof(unsigned long)-1)) 4133 return -EINVAL; 4134 4135 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) 4136 return -ENOMEM; 4137 4138 ret = sched_getaffinity(pid, mask); 4139 if (ret == 0) { 4140 size_t retlen = min_t(size_t, len, cpumask_size()); 4141 4142 if (copy_to_user(user_mask_ptr, mask, retlen)) 4143 ret = -EFAULT; 4144 else 4145 ret = retlen; 4146 } 4147 free_cpumask_var(mask); 4148 4149 return ret; 4150} 4151 4152/** 4153 * sys_sched_yield - yield the current processor to other threads. 4154 * 4155 * This function yields the current CPU to other tasks. If there are no 4156 * other threads running on this CPU then this function will return. 4157 * 4158 * Return: 0. 4159 */ 4160SYSCALL_DEFINE0(sched_yield) 4161{ 4162 struct rq *rq = this_rq_lock(); 4163 4164 schedstat_inc(rq, yld_count); 4165 current->sched_class->yield_task(rq); 4166 4167 /* 4168 * Since we are going to call schedule() anyway, there's 4169 * no need to preempt or enable interrupts: 4170 */ 4171 __release(rq->lock); 4172 spin_release(&rq->lock.dep_map, 1, _THIS_IP_); 4173 do_raw_spin_unlock(&rq->lock); 4174 sched_preempt_enable_no_resched(); 4175 4176 schedule(); 4177 4178 return 0; 4179} 4180 4181static void __cond_resched(void) 4182{ 4183 __preempt_count_add(PREEMPT_ACTIVE); 4184 __schedule(); 4185 __preempt_count_sub(PREEMPT_ACTIVE); 4186} 4187 4188int __sched _cond_resched(void) 4189{ 4190 if (should_resched()) { 4191 __cond_resched(); 4192 return 1; 4193 } 4194 return 0; 4195} 4196EXPORT_SYMBOL(_cond_resched); 4197 4198/* 4199 * __cond_resched_lock() - if a reschedule is pending, drop the given lock, 4200 * call schedule, and on return reacquire the lock. 4201 * 4202 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level 4203 * operations here to prevent schedule() from being called twice (once via 4204 * spin_unlock(), once by hand). 4205 */ 4206int __cond_resched_lock(spinlock_t *lock) 4207{ 4208 int resched = should_resched(); 4209 int ret = 0; 4210 4211 lockdep_assert_held(lock); 4212 4213 if (spin_needbreak(lock) || resched) { 4214 spin_unlock(lock); 4215 if (resched) 4216 __cond_resched(); 4217 else 4218 cpu_relax(); 4219 ret = 1; 4220 spin_lock(lock); 4221 } 4222 return ret; 4223} 4224EXPORT_SYMBOL(__cond_resched_lock); 4225 4226int __sched __cond_resched_softirq(void) 4227{ 4228 BUG_ON(!in_softirq()); 4229 4230 if (should_resched()) { 4231 local_bh_enable(); 4232 __cond_resched(); 4233 local_bh_disable(); 4234 return 1; 4235 } 4236 return 0; 4237} 4238EXPORT_SYMBOL(__cond_resched_softirq); 4239 4240/** 4241 * yield - yield the current processor to other threads. 4242 * 4243 * Do not ever use this function, there's a 99% chance you're doing it wrong. 4244 * 4245 * The scheduler is at all times free to pick the calling task as the most 4246 * eligible task to run, if removing the yield() call from your code breaks 4247 * it, its already broken. 4248 * 4249 * Typical broken usage is: 4250 * 4251 * while (!event) 4252 * yield(); 4253 * 4254 * where one assumes that yield() will let 'the other' process run that will 4255 * make event true. If the current task is a SCHED_FIFO task that will never 4256 * happen. Never use yield() as a progress guarantee!! 4257 * 4258 * If you want to use yield() to wait for something, use wait_event(). 4259 * If you want to use yield() to be 'nice' for others, use cond_resched(). 4260 * If you still want to use yield(), do not! 4261 */ 4262void __sched yield(void) 4263{ 4264 set_current_state(TASK_RUNNING); 4265 sys_sched_yield(); 4266} 4267EXPORT_SYMBOL(yield); 4268 4269/** 4270 * yield_to - yield the current processor to another thread in 4271 * your thread group, or accelerate that thread toward the 4272 * processor it's on. 4273 * @p: target task 4274 * @preempt: whether task preemption is allowed or not 4275 * 4276 * It's the caller's job to ensure that the target task struct 4277 * can't go away on us before we can do any checks. 4278 * 4279 * Return: 4280 * true (>0) if we indeed boosted the target task. 4281 * false (0) if we failed to boost the target. 4282 * -ESRCH if there's no task to yield to. 4283 */ 4284int __sched yield_to(struct task_struct *p, bool preempt) 4285{ 4286 struct task_struct *curr = current; 4287 struct rq *rq, *p_rq; 4288 unsigned long flags; 4289 int yielded = 0; 4290 4291 local_irq_save(flags); 4292 rq = this_rq(); 4293 4294again: 4295 p_rq = task_rq(p); 4296 /* 4297 * If we're the only runnable task on the rq and target rq also 4298 * has only one task, there's absolutely no point in yielding. 4299 */ 4300 if (rq->nr_running == 1 && p_rq->nr_running == 1) { 4301 yielded = -ESRCH; 4302 goto out_irq; 4303 } 4304 4305 double_rq_lock(rq, p_rq); 4306 if (task_rq(p) != p_rq) { 4307 double_rq_unlock(rq, p_rq); 4308 goto again; 4309 } 4310 4311 if (!curr->sched_class->yield_to_task) 4312 goto out_unlock; 4313 4314 if (curr->sched_class != p->sched_class) 4315 goto out_unlock; 4316 4317 if (task_running(p_rq, p) || p->state) 4318 goto out_unlock; 4319 4320 yielded = curr->sched_class->yield_to_task(rq, p, preempt); 4321 if (yielded) { 4322 schedstat_inc(rq, yld_count); 4323 /* 4324 * Make p's CPU reschedule; pick_next_entity takes care of 4325 * fairness. 4326 */ 4327 if (preempt && rq != p_rq) 4328 resched_curr(p_rq); 4329 } 4330 4331out_unlock: 4332 double_rq_unlock(rq, p_rq); 4333out_irq: 4334 local_irq_restore(flags); 4335 4336 if (yielded > 0) 4337 schedule(); 4338 4339 return yielded; 4340} 4341EXPORT_SYMBOL_GPL(yield_to); 4342 4343/* 4344 * This task is about to go to sleep on IO. Increment rq->nr_iowait so 4345 * that process accounting knows that this is a task in IO wait state. 4346 */ 4347void __sched io_schedule(void) 4348{ 4349 struct rq *rq = raw_rq(); 4350 4351 delayacct_blkio_start(); 4352 atomic_inc(&rq->nr_iowait); 4353 blk_flush_plug(current); 4354 current->in_iowait = 1; 4355 schedule(); 4356 current->in_iowait = 0; 4357 atomic_dec(&rq->nr_iowait); 4358 delayacct_blkio_end(); 4359} 4360EXPORT_SYMBOL(io_schedule); 4361 4362long __sched io_schedule_timeout(long timeout) 4363{ 4364 struct rq *rq = raw_rq(); 4365 long ret; 4366 4367 delayacct_blkio_start(); 4368 atomic_inc(&rq->nr_iowait); 4369 blk_flush_plug(current); 4370 current->in_iowait = 1; 4371 ret = schedule_timeout(timeout); 4372 current->in_iowait = 0; 4373 atomic_dec(&rq->nr_iowait); 4374 delayacct_blkio_end(); 4375 return ret; 4376} 4377 4378/** 4379 * sys_sched_get_priority_max - return maximum RT priority. 4380 * @policy: scheduling class. 4381 * 4382 * Return: On success, this syscall returns the maximum 4383 * rt_priority that can be used by a given scheduling class. 4384 * On failure, a negative error code is returned. 4385 */ 4386SYSCALL_DEFINE1(sched_get_priority_max, int, policy) 4387{ 4388 int ret = -EINVAL; 4389 4390 switch (policy) { 4391 case SCHED_FIFO: 4392 case SCHED_RR: 4393 ret = MAX_USER_RT_PRIO-1; 4394 break; 4395 case SCHED_DEADLINE: 4396 case SCHED_NORMAL: 4397 case SCHED_BATCH: 4398 case SCHED_IDLE: 4399 ret = 0; 4400 break; 4401 } 4402 return ret; 4403} 4404 4405/** 4406 * sys_sched_get_priority_min - return minimum RT priority. 4407 * @policy: scheduling class. 4408 * 4409 * Return: On success, this syscall returns the minimum 4410 * rt_priority that can be used by a given scheduling class. 4411 * On failure, a negative error code is returned. 4412 */ 4413SYSCALL_DEFINE1(sched_get_priority_min, int, policy) 4414{ 4415 int ret = -EINVAL; 4416 4417 switch (policy) { 4418 case SCHED_FIFO: 4419 case SCHED_RR: 4420 ret = 1; 4421 break; 4422 case SCHED_DEADLINE: 4423 case SCHED_NORMAL: 4424 case SCHED_BATCH: 4425 case SCHED_IDLE: 4426 ret = 0; 4427 } 4428 return ret; 4429} 4430 4431/** 4432 * sys_sched_rr_get_interval - return the default timeslice of a process. 4433 * @pid: pid of the process. 4434 * @interval: userspace pointer to the timeslice value. 4435 * 4436 * this syscall writes the default timeslice value of a given process 4437 * into the user-space timespec buffer. A value of '0' means infinity. 4438 * 4439 * Return: On success, 0 and the timeslice is in @interval. Otherwise, 4440 * an error code. 4441 */ 4442SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid, 4443 struct timespec __user *, interval) 4444{ 4445 struct task_struct *p; 4446 unsigned int time_slice; 4447 unsigned long flags; 4448 struct rq *rq; 4449 int retval; 4450 struct timespec t; 4451 4452 if (pid < 0) 4453 return -EINVAL; 4454 4455 retval = -ESRCH; 4456 rcu_read_lock(); 4457 p = find_process_by_pid(pid); 4458 if (!p) 4459 goto out_unlock; 4460 4461 retval = security_task_getscheduler(p); 4462 if (retval) 4463 goto out_unlock; 4464 4465 rq = task_rq_lock(p, &flags); 4466 time_slice = 0; 4467 if (p->sched_class->get_rr_interval) 4468 time_slice = p->sched_class->get_rr_interval(rq, p); 4469 task_rq_unlock(rq, p, &flags); 4470 4471 rcu_read_unlock(); 4472 jiffies_to_timespec(time_slice, &t); 4473 retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; 4474 return retval; 4475 4476out_unlock: 4477 rcu_read_unlock(); 4478 return retval; 4479} 4480 4481static const char stat_nam[] = TASK_STATE_TO_CHAR_STR; 4482 4483void sched_show_task(struct task_struct *p) 4484{ 4485 unsigned long free = 0; 4486 int ppid; 4487 unsigned state; 4488 4489 state = p->state ? __ffs(p->state) + 1 : 0; 4490 printk(KERN_INFO "%-15.15s %c", p->comm, 4491 state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); 4492#if BITS_PER_LONG == 32 4493 if (state == TASK_RUNNING) 4494 printk(KERN_CONT " running "); 4495 else 4496 printk(KERN_CONT " %08lx ", thread_saved_pc(p)); 4497#else 4498 if (state == TASK_RUNNING) 4499 printk(KERN_CONT " running task "); 4500 else 4501 printk(KERN_CONT " %016lx ", thread_saved_pc(p)); 4502#endif 4503#ifdef CONFIG_DEBUG_STACK_USAGE 4504 free = stack_not_used(p); 4505#endif 4506 rcu_read_lock(); 4507 ppid = task_pid_nr(rcu_dereference(p->real_parent)); 4508 rcu_read_unlock(); 4509 printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free, 4510 task_pid_nr(p), ppid, 4511 (unsigned long)task_thread_info(p)->flags); 4512 4513 print_worker_info(KERN_INFO, p); 4514 show_stack(p, NULL); 4515} 4516 4517void show_state_filter(unsigned long state_filter) 4518{ 4519 struct task_struct *g, *p; 4520 4521#if BITS_PER_LONG == 32 4522 printk(KERN_INFO 4523 " task PC stack pid father\n"); 4524#else 4525 printk(KERN_INFO 4526 " task PC stack pid father\n"); 4527#endif 4528 rcu_read_lock(); 4529 for_each_process_thread(g, p) { 4530 /* 4531 * reset the NMI-timeout, listing all files on a slow 4532 * console might take a lot of time: 4533 */ 4534 touch_nmi_watchdog(); 4535 if (!state_filter || (p->state & state_filter)) 4536 sched_show_task(p); 4537 } 4538 4539 touch_all_softlockup_watchdogs(); 4540 4541#ifdef CONFIG_SCHED_DEBUG 4542 sysrq_sched_debug_show(); 4543#endif 4544 rcu_read_unlock(); 4545 /* 4546 * Only show locks if all tasks are dumped: 4547 */ 4548 if (!state_filter) 4549 debug_show_all_locks(); 4550} 4551 4552void init_idle_bootup_task(struct task_struct *idle) 4553{ 4554 idle->sched_class = &idle_sched_class; 4555} 4556 4557/** 4558 * init_idle - set up an idle thread for a given CPU 4559 * @idle: task in question 4560 * @cpu: cpu the idle task belongs to 4561 * 4562 * NOTE: this function does not set the idle thread's NEED_RESCHED 4563 * flag, to make booting more robust. 4564 */ 4565void init_idle(struct task_struct *idle, int cpu) 4566{ 4567 struct rq *rq = cpu_rq(cpu); 4568 unsigned long flags; 4569 4570 raw_spin_lock_irqsave(&rq->lock, flags); 4571 4572 __sched_fork(0, idle); 4573 idle->state = TASK_RUNNING; 4574 idle->se.exec_start = sched_clock(); 4575 4576 do_set_cpus_allowed(idle, cpumask_of(cpu)); 4577 /* 4578 * We're having a chicken and egg problem, even though we are 4579 * holding rq->lock, the cpu isn't yet set to this cpu so the 4580 * lockdep check in task_group() will fail. 4581 * 4582 * Similar case to sched_fork(). / Alternatively we could 4583 * use task_rq_lock() here and obtain the other rq->lock. 4584 * 4585 * Silence PROVE_RCU 4586 */ 4587 rcu_read_lock(); 4588 __set_task_cpu(idle, cpu); 4589 rcu_read_unlock(); 4590 4591 rq->curr = rq->idle = idle; 4592 idle->on_rq = TASK_ON_RQ_QUEUED; 4593#if defined(CONFIG_SMP) 4594 idle->on_cpu = 1; 4595#endif 4596 raw_spin_unlock_irqrestore(&rq->lock, flags); 4597 4598 /* Set the preempt count _outside_ the spinlocks! */ 4599 init_idle_preempt_count(idle, cpu); 4600 4601 /* 4602 * The idle tasks have their own, simple scheduling class: 4603 */ 4604 idle->sched_class = &idle_sched_class; 4605 ftrace_graph_init_idle_task(idle, cpu); 4606 vtime_init_idle(idle, cpu); 4607#if defined(CONFIG_SMP) 4608 sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu); 4609#endif 4610} 4611 4612#ifdef CONFIG_SMP 4613void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) 4614{ 4615 if (p->sched_class && p->sched_class->set_cpus_allowed) 4616 p->sched_class->set_cpus_allowed(p, new_mask); 4617 4618 cpumask_copy(&p->cpus_allowed, new_mask); 4619 p->nr_cpus_allowed = cpumask_weight(new_mask); 4620} 4621 4622/* 4623 * This is how migration works: 4624 * 4625 * 1) we invoke migration_cpu_stop() on the target CPU using 4626 * stop_one_cpu(). 4627 * 2) stopper starts to run (implicitly forcing the migrated thread 4628 * off the CPU) 4629 * 3) it checks whether the migrated task is still in the wrong runqueue. 4630 * 4) if it's in the wrong runqueue then the migration thread removes 4631 * it and puts it into the right queue. 4632 * 5) stopper completes and stop_one_cpu() returns and the migration 4633 * is done. 4634 */ 4635 4636/* 4637 * Change a given task's CPU affinity. Migrate the thread to a 4638 * proper CPU and schedule it away if the CPU it's executing on 4639 * is removed from the allowed bitmask. 4640 * 4641 * NOTE: the caller must have a valid reference to the task, the 4642 * task must not exit() & deallocate itself prematurely. The 4643 * call is not atomic; no spinlocks may be held. 4644 */ 4645int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) 4646{ 4647 unsigned long flags; 4648 struct rq *rq; 4649 unsigned int dest_cpu; 4650 int ret = 0; 4651 4652 rq = task_rq_lock(p, &flags); 4653 4654 if (cpumask_equal(&p->cpus_allowed, new_mask)) 4655 goto out; 4656 4657 if (!cpumask_intersects(new_mask, cpu_active_mask)) { 4658 ret = -EINVAL; 4659 goto out; 4660 } 4661 4662 do_set_cpus_allowed(p, new_mask); 4663 4664 /* Can the task run on the task's current CPU? If so, we're done */ 4665 if (cpumask_test_cpu(task_cpu(p), new_mask)) 4666 goto out; 4667 4668 dest_cpu = cpumask_any_and(cpu_active_mask, new_mask); 4669 if (task_on_rq_queued(p) || p->state == TASK_WAKING) { 4670 struct migration_arg arg = { p, dest_cpu }; 4671 /* Need help from migration thread: drop lock and wait. */ 4672 task_rq_unlock(rq, p, &flags); 4673 stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg); 4674 tlb_migrate_finish(p->mm); 4675 return 0; 4676 } 4677out: 4678 task_rq_unlock(rq, p, &flags); 4679 4680 return ret; 4681} 4682EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr); 4683 4684/* 4685 * Move (not current) task off this cpu, onto dest cpu. We're doing 4686 * this because either it can't run here any more (set_cpus_allowed() 4687 * away from this CPU, or CPU going down), or because we're 4688 * attempting to rebalance this task on exec (sched_exec). 4689 * 4690 * So we race with normal scheduler movements, but that's OK, as long 4691 * as the task is no longer on this CPU. 4692 * 4693 * Returns non-zero if task was successfully migrated. 4694 */ 4695static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) 4696{ 4697 struct rq *rq; 4698 int ret = 0; 4699 4700 if (unlikely(!cpu_active(dest_cpu))) 4701 return ret; 4702 4703 rq = cpu_rq(src_cpu); 4704 4705 raw_spin_lock(&p->pi_lock); 4706 raw_spin_lock(&rq->lock); 4707 /* Already moved. */ 4708 if (task_cpu(p) != src_cpu) 4709 goto done; 4710 4711 /* Affinity changed (again). */ 4712 if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) 4713 goto fail; 4714 4715 /* 4716 * If we're not on a rq, the next wake-up will ensure we're 4717 * placed properly. 4718 */ 4719 if (task_on_rq_queued(p)) { 4720 dequeue_task(rq, p, 0); 4721 p->on_rq = TASK_ON_RQ_MIGRATING; 4722 set_task_cpu(p, dest_cpu); 4723 raw_spin_unlock(&rq->lock); 4724 4725 rq = cpu_rq(dest_cpu); 4726 raw_spin_lock(&rq->lock); 4727 BUG_ON(task_rq(p) != rq); 4728 p->on_rq = TASK_ON_RQ_QUEUED; 4729 enqueue_task(rq, p, 0); 4730 check_preempt_curr(rq, p, 0); 4731 } 4732done: 4733 ret = 1; 4734fail: 4735 raw_spin_unlock(&rq->lock); 4736 raw_spin_unlock(&p->pi_lock); 4737 return ret; 4738} 4739 4740#ifdef CONFIG_NUMA_BALANCING 4741/* Migrate current task p to target_cpu */ 4742int migrate_task_to(struct task_struct *p, int target_cpu) 4743{ 4744 struct migration_arg arg = { p, target_cpu }; 4745 int curr_cpu = task_cpu(p); 4746 4747 if (curr_cpu == target_cpu) 4748 return 0; 4749 4750 if (!cpumask_test_cpu(target_cpu, tsk_cpus_allowed(p))) 4751 return -EINVAL; 4752 4753 /* TODO: This is not properly updating schedstats */ 4754 4755 trace_sched_move_numa(p, curr_cpu, target_cpu); 4756 return stop_one_cpu(curr_cpu, migration_cpu_stop, &arg); 4757} 4758 4759/* 4760 * Requeue a task on a given node and accurately track the number of NUMA 4761 * tasks on the runqueues 4762 */ 4763void sched_setnuma(struct task_struct *p, int nid) 4764{ 4765 struct rq *rq; 4766 unsigned long flags; 4767 bool queued, running; 4768 4769 rq = task_rq_lock(p, &flags); 4770 queued = task_on_rq_queued(p); 4771 running = task_current(rq, p); 4772 4773 if (queued) 4774 dequeue_task(rq, p, 0); 4775 if (running) 4776 p->sched_class->put_prev_task(rq, p); 4777 4778 p->numa_preferred_nid = nid; 4779 4780 if (running) 4781 p->sched_class->set_curr_task(rq); 4782 if (queued) 4783 enqueue_task(rq, p, 0); 4784 task_rq_unlock(rq, p, &flags); 4785} 4786#endif 4787 4788/* 4789 * migration_cpu_stop - this will be executed by a highprio stopper thread 4790 * and performs thread migration by bumping thread off CPU then 4791 * 'pushing' onto another runqueue. 4792 */ 4793static int migration_cpu_stop(void *data) 4794{ 4795 struct migration_arg *arg = data; 4796 4797 /* 4798 * The original target cpu might have gone down and we might 4799 * be on another cpu but it doesn't matter. 4800 */ 4801 local_irq_disable(); 4802 /* 4803 * We need to explicitly wake pending tasks before running 4804 * __migrate_task() such that we will not miss enforcing cpus_allowed 4805 * during wakeups, see set_cpus_allowed_ptr()'s TASK_WAKING test. 4806 */ 4807 sched_ttwu_pending(); 4808 __migrate_task(arg->task, raw_smp_processor_id(), arg->dest_cpu); 4809 local_irq_enable(); 4810 return 0; 4811} 4812 4813#ifdef CONFIG_HOTPLUG_CPU 4814 4815/* 4816 * Ensures that the idle task is using init_mm right before its cpu goes 4817 * offline. 4818 */ 4819void idle_task_exit(void) 4820{ 4821 struct mm_struct *mm = current->active_mm; 4822 4823 BUG_ON(cpu_online(smp_processor_id())); 4824 4825 if (mm != &init_mm) { 4826 switch_mm(mm, &init_mm, current); 4827 finish_arch_post_lock_switch(); 4828 } 4829 mmdrop(mm); 4830} 4831 4832/* 4833 * Since this CPU is going 'away' for a while, fold any nr_active delta 4834 * we might have. Assumes we're called after migrate_tasks() so that the 4835 * nr_active count is stable. 4836 * 4837 * Also see the comment "Global load-average calculations". 4838 */ 4839static void calc_load_migrate(struct rq *rq) 4840{ 4841 long delta = calc_load_fold_active(rq); 4842 if (delta) 4843 atomic_long_add(delta, &calc_load_tasks); 4844} 4845 4846static void put_prev_task_fake(struct rq *rq, struct task_struct *prev) 4847{ 4848} 4849 4850static const struct sched_class fake_sched_class = { 4851 .put_prev_task = put_prev_task_fake, 4852}; 4853 4854static struct task_struct fake_task = { 4855 /* 4856 * Avoid pull_{rt,dl}_task() 4857 */ 4858 .prio = MAX_PRIO + 1, 4859 .sched_class = &fake_sched_class, 4860}; 4861 4862/* 4863 * Migrate all tasks from the rq, sleeping tasks will be migrated by 4864 * try_to_wake_up()->select_task_rq(). 4865 * 4866 * Called with rq->lock held even though we'er in stop_machine() and 4867 * there's no concurrency possible, we hold the required locks anyway 4868 * because of lock validation efforts. 4869 */ 4870static void migrate_tasks(unsigned int dead_cpu) 4871{ 4872 struct rq *rq = cpu_rq(dead_cpu); 4873 struct task_struct *next, *stop = rq->stop; 4874 int dest_cpu; 4875 4876 /* 4877 * Fudge the rq selection such that the below task selection loop 4878 * doesn't get stuck on the currently eligible stop task. 4879 * 4880 * We're currently inside stop_machine() and the rq is either stuck 4881 * in the stop_machine_cpu_stop() loop, or we're executing this code, 4882 * either way we should never end up calling schedule() until we're 4883 * done here. 4884 */ 4885 rq->stop = NULL; 4886 4887 /* 4888 * put_prev_task() and pick_next_task() sched 4889 * class method both need to have an up-to-date 4890 * value of rq->clock[_task] 4891 */ 4892 update_rq_clock(rq); 4893 4894 for ( ; ; ) { 4895 /* 4896 * There's this thread running, bail when that's the only 4897 * remaining thread. 4898 */ 4899 if (rq->nr_running == 1) 4900 break; 4901 4902 next = pick_next_task(rq, &fake_task); 4903 BUG_ON(!next); 4904 next->sched_class->put_prev_task(rq, next); 4905 4906 /* Find suitable destination for @next, with force if needed. */ 4907 dest_cpu = select_fallback_rq(dead_cpu, next); 4908 raw_spin_unlock(&rq->lock); 4909 4910 __migrate_task(next, dead_cpu, dest_cpu); 4911 4912 raw_spin_lock(&rq->lock); 4913 } 4914 4915 rq->stop = stop; 4916} 4917 4918#endif /* CONFIG_HOTPLUG_CPU */ 4919 4920#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL) 4921 4922static struct ctl_table sd_ctl_dir[] = { 4923 { 4924 .procname = "sched_domain", 4925 .mode = 0555, 4926 }, 4927 {} 4928}; 4929 4930static struct ctl_table sd_ctl_root[] = { 4931 { 4932 .procname = "kernel", 4933 .mode = 0555, 4934 .child = sd_ctl_dir, 4935 }, 4936 {} 4937}; 4938 4939static struct ctl_table *sd_alloc_ctl_entry(int n) 4940{ 4941 struct ctl_table *entry = 4942 kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL); 4943 4944 return entry; 4945} 4946 4947static void sd_free_ctl_entry(struct ctl_table **tablep) 4948{ 4949 struct ctl_table *entry; 4950 4951 /* 4952 * In the intermediate directories, both the child directory and 4953 * procname are dynamically allocated and could fail but the mode 4954 * will always be set. In the lowest directory the names are 4955 * static strings and all have proc handlers. 4956 */ 4957 for (entry = *tablep; entry->mode; entry++) { 4958 if (entry->child) 4959 sd_free_ctl_entry(&entry->child); 4960 if (entry->proc_handler == NULL) 4961 kfree(entry->procname); 4962 } 4963 4964 kfree(*tablep); 4965 *tablep = NULL; 4966} 4967 4968static int min_load_idx = 0; 4969static int max_load_idx = CPU_LOAD_IDX_MAX-1; 4970 4971static void 4972set_table_entry(struct ctl_table *entry, 4973 const char *procname, void *data, int maxlen, 4974 umode_t mode, proc_handler *proc_handler, 4975 bool load_idx) 4976{ 4977 entry->procname = procname; 4978 entry->data = data; 4979 entry->maxlen = maxlen; 4980 entry->mode = mode; 4981 entry->proc_handler = proc_handler; 4982 4983 if (load_idx) { 4984 entry->extra1 = &min_load_idx; 4985 entry->extra2 = &max_load_idx; 4986 } 4987} 4988 4989static struct ctl_table * 4990sd_alloc_ctl_domain_table(struct sched_domain *sd) 4991{ 4992 struct ctl_table *table = sd_alloc_ctl_entry(14); 4993 4994 if (table == NULL) 4995 return NULL; 4996 4997 set_table_entry(&table[0], "min_interval", &sd->min_interval, 4998 sizeof(long), 0644, proc_doulongvec_minmax, false); 4999 set_table_entry(&table[1], "max_interval", &sd->max_interval, 5000 sizeof(long), 0644, proc_doulongvec_minmax, false); 5001 set_table_entry(&table[2], "busy_idx", &sd->busy_idx, 5002 sizeof(int), 0644, proc_dointvec_minmax, true); 5003 set_table_entry(&table[3], "idle_idx", &sd->idle_idx, 5004 sizeof(int), 0644, proc_dointvec_minmax, true); 5005 set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx, 5006 sizeof(int), 0644, proc_dointvec_minmax, true); 5007 set_table_entry(&table[5], "wake_idx", &sd->wake_idx, 5008 sizeof(int), 0644, proc_dointvec_minmax, true); 5009 set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx, 5010 sizeof(int), 0644, proc_dointvec_minmax, true); 5011 set_table_entry(&table[7], "busy_factor", &sd->busy_factor, 5012 sizeof(int), 0644, proc_dointvec_minmax, false); 5013 set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct, 5014 sizeof(int), 0644, proc_dointvec_minmax, false); 5015 set_table_entry(&table[9], "cache_nice_tries", 5016 &sd->cache_nice_tries, 5017 sizeof(int), 0644, proc_dointvec_minmax, false); 5018 set_table_entry(&table[10], "flags", &sd->flags, 5019 sizeof(int), 0644, proc_dointvec_minmax, false); 5020 set_table_entry(&table[11], "max_newidle_lb_cost", 5021 &sd->max_newidle_lb_cost, 5022 sizeof(long), 0644, proc_doulongvec_minmax, false); 5023 set_table_entry(&table[12], "name", sd->name, 5024 CORENAME_MAX_SIZE, 0444, proc_dostring, false); 5025 /* &table[13] is terminator */ 5026 5027 return table; 5028} 5029 5030static struct ctl_table *sd_alloc_ctl_cpu_table(int cpu) 5031{ 5032 struct ctl_table *entry, *table; 5033 struct sched_domain *sd; 5034 int domain_num = 0, i; 5035 char buf[32]; 5036 5037 for_each_domain(cpu, sd) 5038 domain_num++; 5039 entry = table = sd_alloc_ctl_entry(domain_num + 1); 5040 if (table == NULL) 5041 return NULL; 5042 5043 i = 0; 5044 for_each_domain(cpu, sd) { 5045 snprintf(buf, 32, "domain%d", i); 5046 entry->procname = kstrdup(buf, GFP_KERNEL); 5047 entry->mode = 0555; 5048 entry->child = sd_alloc_ctl_domain_table(sd); 5049 entry++; 5050 i++; 5051 } 5052 return table; 5053} 5054 5055static struct ctl_table_header *sd_sysctl_header; 5056static void register_sched_domain_sysctl(void) 5057{ 5058 int i, cpu_num = num_possible_cpus(); 5059 struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1); 5060 char buf[32]; 5061 5062 WARN_ON(sd_ctl_dir[0].child); 5063 sd_ctl_dir[0].child = entry; 5064 5065 if (entry == NULL) 5066 return; 5067 5068 for_each_possible_cpu(i) { 5069 snprintf(buf, 32, "cpu%d", i); 5070 entry->procname = kstrdup(buf, GFP_KERNEL); 5071 entry->mode = 0555; 5072 entry->child = sd_alloc_ctl_cpu_table(i); 5073 entry++; 5074 } 5075 5076 WARN_ON(sd_sysctl_header); 5077 sd_sysctl_header = register_sysctl_table(sd_ctl_root); 5078} 5079 5080/* may be called multiple times per register */ 5081static void unregister_sched_domain_sysctl(void) 5082{ 5083 if (sd_sysctl_header) 5084 unregister_sysctl_table(sd_sysctl_header); 5085 sd_sysctl_header = NULL; 5086 if (sd_ctl_dir[0].child) 5087 sd_free_ctl_entry(&sd_ctl_dir[0].child); 5088} 5089#else 5090static void register_sched_domain_sysctl(void) 5091{ 5092} 5093static void unregister_sched_domain_sysctl(void) 5094{ 5095} 5096#endif 5097 5098static void set_rq_online(struct rq *rq) 5099{ 5100 if (!rq->online) { 5101 const struct sched_class *class; 5102 5103 cpumask_set_cpu(rq->cpu, rq->rd->online); 5104 rq->online = 1; 5105 5106 for_each_class(class) { 5107 if (class->rq_online) 5108 class->rq_online(rq); 5109 } 5110 } 5111} 5112 5113static void set_rq_offline(struct rq *rq) 5114{ 5115 if (rq->online) { 5116 const struct sched_class *class; 5117 5118 for_each_class(class) { 5119 if (class->rq_offline) 5120 class->rq_offline(rq); 5121 } 5122 5123 cpumask_clear_cpu(rq->cpu, rq->rd->online); 5124 rq->online = 0; 5125 } 5126} 5127 5128/* 5129 * migration_call - callback that gets triggered when a CPU is added. 5130 * Here we can start up the necessary migration thread for the new CPU. 5131 */ 5132static int 5133migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) 5134{ 5135 int cpu = (long)hcpu; 5136 unsigned long flags; 5137 struct rq *rq = cpu_rq(cpu); 5138 5139 switch (action & ~CPU_TASKS_FROZEN) { 5140 5141 case CPU_UP_PREPARE: 5142 rq->calc_load_update = calc_load_update; 5143 break; 5144 5145 case CPU_ONLINE: 5146 /* Update our root-domain */ 5147 raw_spin_lock_irqsave(&rq->lock, flags); 5148 if (rq->rd) { 5149 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); 5150 5151 set_rq_online(rq); 5152 } 5153 raw_spin_unlock_irqrestore(&rq->lock, flags); 5154 break; 5155 5156#ifdef CONFIG_HOTPLUG_CPU 5157 case CPU_DYING: 5158 sched_ttwu_pending(); 5159 /* Update our root-domain */ 5160 raw_spin_lock_irqsave(&rq->lock, flags); 5161 if (rq->rd) { 5162 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); 5163 set_rq_offline(rq); 5164 } 5165 migrate_tasks(cpu); 5166 BUG_ON(rq->nr_running != 1); /* the migration thread */ 5167 raw_spin_unlock_irqrestore(&rq->lock, flags); 5168 break; 5169 5170 case CPU_DEAD: 5171 calc_load_migrate(rq); 5172 break; 5173#endif 5174 } 5175 5176 update_max_interval(); 5177 5178 return NOTIFY_OK; 5179} 5180 5181/* 5182 * Register at high priority so that task migration (migrate_all_tasks) 5183 * happens before everything else. This has to be lower priority than 5184 * the notifier in the perf_event subsystem, though. 5185 */ 5186static struct notifier_block migration_notifier = { 5187 .notifier_call = migration_call, 5188 .priority = CPU_PRI_MIGRATION, 5189}; 5190 5191static void __cpuinit set_cpu_rq_start_time(void) 5192{ 5193 int cpu = smp_processor_id(); 5194 struct rq *rq = cpu_rq(cpu); 5195 rq->age_stamp = sched_clock_cpu(cpu); 5196} 5197 5198static int sched_cpu_active(struct notifier_block *nfb, 5199 unsigned long action, void *hcpu) 5200{ 5201 switch (action & ~CPU_TASKS_FROZEN) { 5202 case CPU_STARTING: 5203 set_cpu_rq_start_time(); 5204 return NOTIFY_OK; 5205 case CPU_DOWN_FAILED: 5206 set_cpu_active((long)hcpu, true); 5207 return NOTIFY_OK; 5208 default: 5209 return NOTIFY_DONE; 5210 } 5211} 5212 5213static int sched_cpu_inactive(struct notifier_block *nfb, 5214 unsigned long action, void *hcpu) 5215{ 5216 unsigned long flags; 5217 long cpu = (long)hcpu; 5218 5219 switch (action & ~CPU_TASKS_FROZEN) { 5220 case CPU_DOWN_PREPARE: 5221 set_cpu_active(cpu, false); 5222 5223 /* explicitly allow suspend */ 5224 if (!(action & CPU_TASKS_FROZEN)) { 5225 struct dl_bw *dl_b = dl_bw_of(cpu); 5226 bool overflow; 5227 int cpus; 5228 5229 raw_spin_lock_irqsave(&dl_b->lock, flags); 5230 cpus = dl_bw_cpus(cpu); 5231 overflow = __dl_overflow(dl_b, cpus, 0, 0); 5232 raw_spin_unlock_irqrestore(&dl_b->lock, flags); 5233 5234 if (overflow) 5235 return notifier_from_errno(-EBUSY); 5236 } 5237 return NOTIFY_OK; 5238 } 5239 5240 return NOTIFY_DONE; 5241} 5242 5243static int __init migration_init(void) 5244{ 5245 void *cpu = (void *)(long)smp_processor_id(); 5246 int err; 5247 5248 /* Initialize migration for the boot CPU */ 5249 err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); 5250 BUG_ON(err == NOTIFY_BAD); 5251 migration_call(&migration_notifier, CPU_ONLINE, cpu); 5252 register_cpu_notifier(&migration_notifier); 5253 5254 /* Register cpu active notifiers */ 5255 cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE); 5256 cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE); 5257 5258 return 0; 5259} 5260early_initcall(migration_init); 5261#endif 5262 5263#ifdef CONFIG_SMP 5264 5265static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */ 5266 5267#ifdef CONFIG_SCHED_DEBUG 5268 5269static __read_mostly int sched_debug_enabled; 5270 5271static int __init sched_debug_setup(char *str) 5272{ 5273 sched_debug_enabled = 1; 5274 5275 return 0; 5276} 5277early_param("sched_debug", sched_debug_setup); 5278 5279static inline bool sched_debug(void) 5280{ 5281 return sched_debug_enabled; 5282} 5283 5284static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, 5285 struct cpumask *groupmask) 5286{ 5287 struct sched_group *group = sd->groups; 5288 char str[256]; 5289 5290 cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd)); 5291 cpumask_clear(groupmask); 5292 5293 printk(KERN_DEBUG "%*s domain %d: ", level, "", level); 5294 5295 if (!(sd->flags & SD_LOAD_BALANCE)) { 5296 printk("does not load-balance\n"); 5297 if (sd->parent) 5298 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain" 5299 " has parent"); 5300 return -1; 5301 } 5302 5303 printk(KERN_CONT "span %s level %s\n", str, sd->name); 5304 5305 if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) { 5306 printk(KERN_ERR "ERROR: domain->span does not contain " 5307 "CPU%d\n", cpu); 5308 } 5309 if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) { 5310 printk(KERN_ERR "ERROR: domain->groups does not contain" 5311 " CPU%d\n", cpu); 5312 } 5313 5314 printk(KERN_DEBUG "%*s groups:", level + 1, ""); 5315 do { 5316 if (!group) { 5317 printk("\n"); 5318 printk(KERN_ERR "ERROR: group is NULL\n"); 5319 break; 5320 } 5321 5322 /* 5323 * Even though we initialize ->capacity to something semi-sane, 5324 * we leave capacity_orig unset. This allows us to detect if 5325 * domain iteration is still funny without causing /0 traps. 5326 */ 5327 if (!group->sgc->capacity_orig) { 5328 printk(KERN_CONT "\n"); 5329 printk(KERN_ERR "ERROR: domain->cpu_capacity not set\n"); 5330 break; 5331 } 5332 5333 if (!cpumask_weight(sched_group_cpus(group))) { 5334 printk(KERN_CONT "\n"); 5335 printk(KERN_ERR "ERROR: empty group\n"); 5336 break; 5337 } 5338 5339 if (!(sd->flags & SD_OVERLAP) && 5340 cpumask_intersects(groupmask, sched_group_cpus(group))) { 5341 printk(KERN_CONT "\n"); 5342 printk(KERN_ERR "ERROR: repeated CPUs\n"); 5343 break; 5344 } 5345 5346 cpumask_or(groupmask, groupmask, sched_group_cpus(group)); 5347 5348 cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group)); 5349 5350 printk(KERN_CONT " %s", str); 5351 if (group->sgc->capacity != SCHED_CAPACITY_SCALE) { 5352 printk(KERN_CONT " (cpu_capacity = %d)", 5353 group->sgc->capacity); 5354 } 5355 5356 group = group->next; 5357 } while (group != sd->groups); 5358 printk(KERN_CONT "\n"); 5359 5360 if (!cpumask_equal(sched_domain_span(sd), groupmask)) 5361 printk(KERN_ERR "ERROR: groups don't span domain->span\n"); 5362 5363 if (sd->parent && 5364 !cpumask_subset(groupmask, sched_domain_span(sd->parent))) 5365 printk(KERN_ERR "ERROR: parent span is not a superset " 5366 "of domain->span\n"); 5367 return 0; 5368} 5369 5370static void sched_domain_debug(struct sched_domain *sd, int cpu) 5371{ 5372 int level = 0; 5373 5374 if (!sched_debug_enabled) 5375 return; 5376 5377 if (!sd) { 5378 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); 5379 return; 5380 } 5381 5382 printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); 5383 5384 for (;;) { 5385 if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask)) 5386 break; 5387 level++; 5388 sd = sd->parent; 5389 if (!sd) 5390 break; 5391 } 5392} 5393#else /* !CONFIG_SCHED_DEBUG */ 5394# define sched_domain_debug(sd, cpu) do { } while (0) 5395static inline bool sched_debug(void) 5396{ 5397 return false; 5398} 5399#endif /* CONFIG_SCHED_DEBUG */ 5400 5401static int sd_degenerate(struct sched_domain *sd) 5402{ 5403 if (cpumask_weight(sched_domain_span(sd)) == 1) 5404 return 1; 5405 5406 /* Following flags need at least 2 groups */ 5407 if (sd->flags & (SD_LOAD_BALANCE | 5408 SD_BALANCE_NEWIDLE | 5409 SD_BALANCE_FORK | 5410 SD_BALANCE_EXEC | 5411 SD_SHARE_CPUCAPACITY | 5412 SD_SHARE_PKG_RESOURCES | 5413 SD_SHARE_POWERDOMAIN)) { 5414 if (sd->groups != sd->groups->next) 5415 return 0; 5416 } 5417 5418 /* Following flags don't use groups */ 5419 if (sd->flags & (SD_WAKE_AFFINE)) 5420 return 0; 5421 5422 return 1; 5423} 5424 5425static int 5426sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) 5427{ 5428 unsigned long cflags = sd->flags, pflags = parent->flags; 5429 5430 if (sd_degenerate(parent)) 5431 return 1; 5432 5433 if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent))) 5434 return 0; 5435 5436 /* Flags needing groups don't count if only 1 group in parent */ 5437 if (parent->groups == parent->groups->next) { 5438 pflags &= ~(SD_LOAD_BALANCE | 5439 SD_BALANCE_NEWIDLE | 5440 SD_BALANCE_FORK | 5441 SD_BALANCE_EXEC | 5442 SD_SHARE_CPUCAPACITY | 5443 SD_SHARE_PKG_RESOURCES | 5444 SD_PREFER_SIBLING | 5445 SD_SHARE_POWERDOMAIN); 5446 if (nr_node_ids == 1) 5447 pflags &= ~SD_SERIALIZE; 5448 } 5449 if (~cflags & pflags) 5450 return 0; 5451 5452 return 1; 5453} 5454 5455static void free_rootdomain(struct rcu_head *rcu) 5456{ 5457 struct root_domain *rd = container_of(rcu, struct root_domain, rcu); 5458 5459 cpupri_cleanup(&rd->cpupri); 5460 cpudl_cleanup(&rd->cpudl); 5461 free_cpumask_var(rd->dlo_mask); 5462 free_cpumask_var(rd->rto_mask); 5463 free_cpumask_var(rd->online); 5464 free_cpumask_var(rd->span); 5465 kfree(rd); 5466} 5467 5468static void rq_attach_root(struct rq *rq, struct root_domain *rd) 5469{ 5470 struct root_domain *old_rd = NULL; 5471 unsigned long flags; 5472 5473 raw_spin_lock_irqsave(&rq->lock, flags); 5474 5475 if (rq->rd) { 5476 old_rd = rq->rd; 5477 5478 if (cpumask_test_cpu(rq->cpu, old_rd->online)) 5479 set_rq_offline(rq); 5480 5481 cpumask_clear_cpu(rq->cpu, old_rd->span); 5482 5483 /* 5484 * If we dont want to free the old_rd yet then 5485 * set old_rd to NULL to skip the freeing later 5486 * in this function: 5487 */ 5488 if (!atomic_dec_and_test(&old_rd->refcount)) 5489 old_rd = NULL; 5490 } 5491 5492 atomic_inc(&rd->refcount); 5493 rq->rd = rd; 5494 5495 cpumask_set_cpu(rq->cpu, rd->span); 5496 if (cpumask_test_cpu(rq->cpu, cpu_active_mask)) 5497 set_rq_online(rq); 5498 5499 raw_spin_unlock_irqrestore(&rq->lock, flags); 5500 5501 if (old_rd) 5502 call_rcu_sched(&old_rd->rcu, free_rootdomain); 5503} 5504 5505static int init_rootdomain(struct root_domain *rd) 5506{ 5507 memset(rd, 0, sizeof(*rd)); 5508 5509 if (!alloc_cpumask_var(&rd->span, GFP_KERNEL)) 5510 goto out; 5511 if (!alloc_cpumask_var(&rd->online, GFP_KERNEL)) 5512 goto free_span; 5513 if (!alloc_cpumask_var(&rd->dlo_mask, GFP_KERNEL)) 5514 goto free_online; 5515 if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL)) 5516 goto free_dlo_mask; 5517 5518 init_dl_bw(&rd->dl_bw); 5519 if (cpudl_init(&rd->cpudl) != 0) 5520 goto free_dlo_mask; 5521 5522 if (cpupri_init(&rd->cpupri) != 0) 5523 goto free_rto_mask; 5524 return 0; 5525 5526free_rto_mask: 5527 free_cpumask_var(rd->rto_mask); 5528free_dlo_mask: 5529 free_cpumask_var(rd->dlo_mask); 5530free_online: 5531 free_cpumask_var(rd->online); 5532free_span: 5533 free_cpumask_var(rd->span); 5534out: 5535 return -ENOMEM; 5536} 5537 5538/* 5539 * By default the system creates a single root-domain with all cpus as 5540 * members (mimicking the global state we have today). 5541 */ 5542struct root_domain def_root_domain; 5543 5544static void init_defrootdomain(void) 5545{ 5546 init_rootdomain(&def_root_domain); 5547 5548 atomic_set(&def_root_domain.refcount, 1); 5549} 5550 5551static struct root_domain *alloc_rootdomain(void) 5552{ 5553 struct root_domain *rd; 5554 5555 rd = kmalloc(sizeof(*rd), GFP_KERNEL); 5556 if (!rd) 5557 return NULL; 5558 5559 if (init_rootdomain(rd) != 0) { 5560 kfree(rd); 5561 return NULL; 5562 } 5563 5564 return rd; 5565} 5566 5567static void free_sched_groups(struct sched_group *sg, int free_sgc) 5568{ 5569 struct sched_group *tmp, *first; 5570 5571 if (!sg) 5572 return; 5573 5574 first = sg; 5575 do { 5576 tmp = sg->next; 5577 5578 if (free_sgc && atomic_dec_and_test(&sg->sgc->ref)) 5579 kfree(sg->sgc); 5580 5581 kfree(sg); 5582 sg = tmp; 5583 } while (sg != first); 5584} 5585 5586static void free_sched_domain(struct rcu_head *rcu) 5587{ 5588 struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu); 5589 5590 /* 5591 * If its an overlapping domain it has private groups, iterate and 5592 * nuke them all. 5593 */ 5594 if (sd->flags & SD_OVERLAP) { 5595 free_sched_groups(sd->groups, 1); 5596 } else if (atomic_dec_and_test(&sd->groups->ref)) { 5597 kfree(sd->groups->sgc); 5598 kfree(sd->groups); 5599 } 5600 kfree(sd); 5601} 5602 5603static void destroy_sched_domain(struct sched_domain *sd, int cpu) 5604{ 5605 call_rcu(&sd->rcu, free_sched_domain); 5606} 5607 5608static void destroy_sched_domains(struct sched_domain *sd, int cpu) 5609{ 5610 for (; sd; sd = sd->parent) 5611 destroy_sched_domain(sd, cpu); 5612} 5613 5614/* 5615 * Keep a special pointer to the highest sched_domain that has 5616 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this 5617 * allows us to avoid some pointer chasing select_idle_sibling(). 5618 * 5619 * Also keep a unique ID per domain (we use the first cpu number in 5620 * the cpumask of the domain), this allows us to quickly tell if 5621 * two cpus are in the same cache domain, see cpus_share_cache(). 5622 */ 5623DEFINE_PER_CPU(struct sched_domain *, sd_llc); 5624DEFINE_PER_CPU(int, sd_llc_size); 5625DEFINE_PER_CPU(int, sd_llc_id); 5626DEFINE_PER_CPU(struct sched_domain *, sd_numa); 5627DEFINE_PER_CPU(struct sched_domain *, sd_busy); 5628DEFINE_PER_CPU(struct sched_domain *, sd_asym); 5629 5630static void update_top_cache_domain(int cpu) 5631{ 5632 struct sched_domain *sd; 5633 struct sched_domain *busy_sd = NULL; 5634 int id = cpu; 5635 int size = 1; 5636 5637 sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES); 5638 if (sd) { 5639 id = cpumask_first(sched_domain_span(sd)); 5640 size = cpumask_weight(sched_domain_span(sd)); 5641 busy_sd = sd->parent; /* sd_busy */ 5642 } 5643 rcu_assign_pointer(per_cpu(sd_busy, cpu), busy_sd); 5644 5645 rcu_assign_pointer(per_cpu(sd_llc, cpu), sd); 5646 per_cpu(sd_llc_size, cpu) = size; 5647 per_cpu(sd_llc_id, cpu) = id; 5648 5649 sd = lowest_flag_domain(cpu, SD_NUMA); 5650 rcu_assign_pointer(per_cpu(sd_numa, cpu), sd); 5651 5652 sd = highest_flag_domain(cpu, SD_ASYM_PACKING); 5653 rcu_assign_pointer(per_cpu(sd_asym, cpu), sd); 5654} 5655 5656/* 5657 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must 5658 * hold the hotplug lock. 5659 */ 5660static void 5661cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) 5662{ 5663 struct rq *rq = cpu_rq(cpu); 5664 struct sched_domain *tmp; 5665 5666 /* Remove the sched domains which do not contribute to scheduling. */ 5667 for (tmp = sd; tmp; ) { 5668 struct sched_domain *parent = tmp->parent; 5669 if (!parent) 5670 break; 5671 5672 if (sd_parent_degenerate(tmp, parent)) { 5673 tmp->parent = parent->parent; 5674 if (parent->parent) 5675 parent->parent->child = tmp; 5676 /* 5677 * Transfer SD_PREFER_SIBLING down in case of a 5678 * degenerate parent; the spans match for this 5679 * so the property transfers. 5680 */ 5681 if (parent->flags & SD_PREFER_SIBLING) 5682 tmp->flags |= SD_PREFER_SIBLING; 5683 destroy_sched_domain(parent, cpu); 5684 } else 5685 tmp = tmp->parent; 5686 } 5687 5688 if (sd && sd_degenerate(sd)) { 5689 tmp = sd; 5690 sd = sd->parent; 5691 destroy_sched_domain(tmp, cpu); 5692 if (sd) 5693 sd->child = NULL; 5694 } 5695 5696 sched_domain_debug(sd, cpu); 5697 5698 rq_attach_root(rq, rd); 5699 tmp = rq->sd; 5700 rcu_assign_pointer(rq->sd, sd); 5701 destroy_sched_domains(tmp, cpu); 5702 5703 update_top_cache_domain(cpu); 5704} 5705 5706/* cpus with isolated domains */ 5707static cpumask_var_t cpu_isolated_map; 5708 5709/* Setup the mask of cpus configured for isolated domains */ 5710static int __init isolated_cpu_setup(char *str) 5711{ 5712 alloc_bootmem_cpumask_var(&cpu_isolated_map); 5713 cpulist_parse(str, cpu_isolated_map); 5714 return 1; 5715} 5716 5717__setup("isolcpus=", isolated_cpu_setup); 5718 5719struct s_data { 5720 struct sched_domain ** __percpu sd; 5721 struct root_domain *rd; 5722}; 5723 5724enum s_alloc { 5725 sa_rootdomain, 5726 sa_sd, 5727 sa_sd_storage, 5728 sa_none, 5729}; 5730 5731/* 5732 * Build an iteration mask that can exclude certain CPUs from the upwards 5733 * domain traversal. 5734 * 5735 * Asymmetric node setups can result in situations where the domain tree is of 5736 * unequal depth, make sure to skip domains that already cover the entire 5737 * range. 5738 * 5739 * In that case build_sched_domains() will have terminated the iteration early 5740 * and our sibling sd spans will be empty. Domains should always include the 5741 * cpu they're built on, so check that. 5742 * 5743 */ 5744static void build_group_mask(struct sched_domain *sd, struct sched_group *sg) 5745{ 5746 const struct cpumask *span = sched_domain_span(sd); 5747 struct sd_data *sdd = sd->private; 5748 struct sched_domain *sibling; 5749 int i; 5750 5751 for_each_cpu(i, span) { 5752 sibling = *per_cpu_ptr(sdd->sd, i); 5753 if (!cpumask_test_cpu(i, sched_domain_span(sibling))) 5754 continue; 5755 5756 cpumask_set_cpu(i, sched_group_mask(sg)); 5757 } 5758} 5759 5760/* 5761 * Return the canonical balance cpu for this group, this is the first cpu 5762 * of this group that's also in the iteration mask. 5763 */ 5764int group_balance_cpu(struct sched_group *sg) 5765{ 5766 return cpumask_first_and(sched_group_cpus(sg), sched_group_mask(sg)); 5767} 5768 5769static int 5770build_overlap_sched_groups(struct sched_domain *sd, int cpu) 5771{ 5772 struct sched_group *first = NULL, *last = NULL, *groups = NULL, *sg; 5773 const struct cpumask *span = sched_domain_span(sd); 5774 struct cpumask *covered = sched_domains_tmpmask; 5775 struct sd_data *sdd = sd->private; 5776 struct sched_domain *sibling; 5777 int i; 5778 5779 cpumask_clear(covered); 5780 5781 for_each_cpu(i, span) { 5782 struct cpumask *sg_span; 5783 5784 if (cpumask_test_cpu(i, covered)) 5785 continue; 5786 5787 sibling = *per_cpu_ptr(sdd->sd, i); 5788 5789 /* See the comment near build_group_mask(). */ 5790 if (!cpumask_test_cpu(i, sched_domain_span(sibling))) 5791 continue; 5792 5793 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), 5794 GFP_KERNEL, cpu_to_node(cpu)); 5795 5796 if (!sg) 5797 goto fail; 5798 5799 sg_span = sched_group_cpus(sg); 5800 if (sibling->child) 5801 cpumask_copy(sg_span, sched_domain_span(sibling->child)); 5802 else 5803 cpumask_set_cpu(i, sg_span); 5804 5805 cpumask_or(covered, covered, sg_span); 5806 5807 sg->sgc = *per_cpu_ptr(sdd->sgc, i); 5808 if (atomic_inc_return(&sg->sgc->ref) == 1) 5809 build_group_mask(sd, sg); 5810 5811 /* 5812 * Initialize sgc->capacity such that even if we mess up the 5813 * domains and no possible iteration will get us here, we won't 5814 * die on a /0 trap. 5815 */ 5816 sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sg_span); 5817 sg->sgc->capacity_orig = sg->sgc->capacity; 5818 5819 /* 5820 * Make sure the first group of this domain contains the 5821 * canonical balance cpu. Otherwise the sched_domain iteration 5822 * breaks. See update_sg_lb_stats(). 5823 */ 5824 if ((!groups && cpumask_test_cpu(cpu, sg_span)) || 5825 group_balance_cpu(sg) == cpu) 5826 groups = sg; 5827 5828 if (!first) 5829 first = sg; 5830 if (last) 5831 last->next = sg; 5832 last = sg; 5833 last->next = first; 5834 } 5835 sd->groups = groups; 5836 5837 return 0; 5838 5839fail: 5840 free_sched_groups(first, 0); 5841 5842 return -ENOMEM; 5843} 5844 5845static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg) 5846{ 5847 struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu); 5848 struct sched_domain *child = sd->child; 5849 5850 if (child) 5851 cpu = cpumask_first(sched_domain_span(child)); 5852 5853 if (sg) { 5854 *sg = *per_cpu_ptr(sdd->sg, cpu); 5855 (*sg)->sgc = *per_cpu_ptr(sdd->sgc, cpu); 5856 atomic_set(&(*sg)->sgc->ref, 1); /* for claim_allocations */ 5857 } 5858 5859 return cpu; 5860} 5861 5862/* 5863 * build_sched_groups will build a circular linked list of the groups 5864 * covered by the given span, and will set each group's ->cpumask correctly, 5865 * and ->cpu_capacity to 0. 5866 * 5867 * Assumes the sched_domain tree is fully constructed 5868 */ 5869static int 5870build_sched_groups(struct sched_domain *sd, int cpu) 5871{ 5872 struct sched_group *first = NULL, *last = NULL; 5873 struct sd_data *sdd = sd->private; 5874 const struct cpumask *span = sched_domain_span(sd); 5875 struct cpumask *covered; 5876 int i; 5877 5878 get_group(cpu, sdd, &sd->groups); 5879 atomic_inc(&sd->groups->ref); 5880 5881 if (cpu != cpumask_first(span)) 5882 return 0; 5883 5884 lockdep_assert_held(&sched_domains_mutex); 5885 covered = sched_domains_tmpmask; 5886 5887 cpumask_clear(covered); 5888 5889 for_each_cpu(i, span) { 5890 struct sched_group *sg; 5891 int group, j; 5892 5893 if (cpumask_test_cpu(i, covered)) 5894 continue; 5895 5896 group = get_group(i, sdd, &sg); 5897 cpumask_setall(sched_group_mask(sg)); 5898 5899 for_each_cpu(j, span) { 5900 if (get_group(j, sdd, NULL) != group) 5901 continue; 5902 5903 cpumask_set_cpu(j, covered); 5904 cpumask_set_cpu(j, sched_group_cpus(sg)); 5905 } 5906 5907 if (!first) 5908 first = sg; 5909 if (last) 5910 last->next = sg; 5911 last = sg; 5912 } 5913 last->next = first; 5914 5915 return 0; 5916} 5917 5918/* 5919 * Initialize sched groups cpu_capacity. 5920 * 5921 * cpu_capacity indicates the capacity of sched group, which is used while 5922 * distributing the load between different sched groups in a sched domain. 5923 * Typically cpu_capacity for all the groups in a sched domain will be same 5924 * unless there are asymmetries in the topology. If there are asymmetries, 5925 * group having more cpu_capacity will pickup more load compared to the 5926 * group having less cpu_capacity. 5927 */ 5928static void init_sched_groups_capacity(int cpu, struct sched_domain *sd) 5929{ 5930 struct sched_group *sg = sd->groups; 5931 5932 WARN_ON(!sg); 5933 5934 do { 5935 sg->group_weight = cpumask_weight(sched_group_cpus(sg)); 5936 sg = sg->next; 5937 } while (sg != sd->groups); 5938 5939 if (cpu != group_balance_cpu(sg)) 5940 return; 5941 5942 update_group_capacity(sd, cpu); 5943 atomic_set(&sg->sgc->nr_busy_cpus, sg->group_weight); 5944} 5945 5946/* 5947 * Initializers for schedule domains 5948 * Non-inlined to reduce accumulated stack pressure in build_sched_domains() 5949 */ 5950 5951static int default_relax_domain_level = -1; 5952int sched_domain_level_max; 5953 5954static int __init setup_relax_domain_level(char *str) 5955{ 5956 if (kstrtoint(str, 0, &default_relax_domain_level)) 5957 pr_warn("Unable to set relax_domain_level\n"); 5958 5959 return 1; 5960} 5961__setup("relax_domain_level=", setup_relax_domain_level); 5962 5963static void set_domain_attribute(struct sched_domain *sd, 5964 struct sched_domain_attr *attr) 5965{ 5966 int request; 5967 5968 if (!attr || attr->relax_domain_level < 0) { 5969 if (default_relax_domain_level < 0) 5970 return; 5971 else 5972 request = default_relax_domain_level; 5973 } else 5974 request = attr->relax_domain_level; 5975 if (request < sd->level) { 5976 /* turn off idle balance on this domain */ 5977 sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); 5978 } else { 5979 /* turn on idle balance on this domain */ 5980 sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); 5981 } 5982} 5983 5984static void __sdt_free(const struct cpumask *cpu_map); 5985static int __sdt_alloc(const struct cpumask *cpu_map); 5986 5987static void __free_domain_allocs(struct s_data *d, enum s_alloc what, 5988 const struct cpumask *cpu_map) 5989{ 5990 switch (what) { 5991 case sa_rootdomain: 5992 if (!atomic_read(&d->rd->refcount)) 5993 free_rootdomain(&d->rd->rcu); /* fall through */ 5994 case sa_sd: 5995 free_percpu(d->sd); /* fall through */ 5996 case sa_sd_storage: 5997 __sdt_free(cpu_map); /* fall through */ 5998 case sa_none: 5999 break; 6000 } 6001} 6002 6003static enum s_alloc __visit_domain_allocation_hell(struct s_data *d, 6004 const struct cpumask *cpu_map) 6005{ 6006 memset(d, 0, sizeof(*d)); 6007 6008 if (__sdt_alloc(cpu_map)) 6009 return sa_sd_storage; 6010 d->sd = alloc_percpu(struct sched_domain *); 6011 if (!d->sd) 6012 return sa_sd_storage; 6013 d->rd = alloc_rootdomain(); 6014 if (!d->rd) 6015 return sa_sd; 6016 return sa_rootdomain; 6017} 6018 6019/* 6020 * NULL the sd_data elements we've used to build the sched_domain and 6021 * sched_group structure so that the subsequent __free_domain_allocs() 6022 * will not free the data we're using. 6023 */ 6024static void claim_allocations(int cpu, struct sched_domain *sd) 6025{ 6026 struct sd_data *sdd = sd->private; 6027 6028 WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd); 6029 *per_cpu_ptr(sdd->sd, cpu) = NULL; 6030 6031 if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref)) 6032 *per_cpu_ptr(sdd->sg, cpu) = NULL; 6033 6034 if (atomic_read(&(*per_cpu_ptr(sdd->sgc, cpu))->ref)) 6035 *per_cpu_ptr(sdd->sgc, cpu) = NULL; 6036} 6037 6038#ifdef CONFIG_NUMA 6039static int sched_domains_numa_levels; 6040static int *sched_domains_numa_distance; 6041static struct cpumask ***sched_domains_numa_masks; 6042static int sched_domains_curr_level; 6043#endif 6044 6045/* 6046 * SD_flags allowed in topology descriptions. 6047 * 6048 * SD_SHARE_CPUCAPACITY - describes SMT topologies 6049 * SD_SHARE_PKG_RESOURCES - describes shared caches 6050 * SD_NUMA - describes NUMA topologies 6051 * SD_SHARE_POWERDOMAIN - describes shared power domain 6052 * 6053 * Odd one out: 6054 * SD_ASYM_PACKING - describes SMT quirks 6055 */ 6056#define TOPOLOGY_SD_FLAGS \ 6057 (SD_SHARE_CPUCAPACITY | \ 6058 SD_SHARE_PKG_RESOURCES | \ 6059 SD_NUMA | \ 6060 SD_ASYM_PACKING | \ 6061 SD_SHARE_POWERDOMAIN) 6062 6063static struct sched_domain * 6064sd_init(struct sched_domain_topology_level *tl, int cpu) 6065{ 6066 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); 6067 int sd_weight, sd_flags = 0; 6068 6069#ifdef CONFIG_NUMA 6070 /* 6071 * Ugly hack to pass state to sd_numa_mask()... 6072 */ 6073 sched_domains_curr_level = tl->numa_level; 6074#endif 6075 6076 sd_weight = cpumask_weight(tl->mask(cpu)); 6077 6078 if (tl->sd_flags) 6079 sd_flags = (*tl->sd_flags)(); 6080 if (WARN_ONCE(sd_flags & ~TOPOLOGY_SD_FLAGS, 6081 "wrong sd_flags in topology description\n")) 6082 sd_flags &= ~TOPOLOGY_SD_FLAGS; 6083 6084 *sd = (struct sched_domain){ 6085 .min_interval = sd_weight, 6086 .max_interval = 2*sd_weight, 6087 .busy_factor = 32, 6088 .imbalance_pct = 125, 6089 6090 .cache_nice_tries = 0, 6091 .busy_idx = 0, 6092 .idle_idx = 0, 6093 .newidle_idx = 0, 6094 .wake_idx = 0, 6095 .forkexec_idx = 0, 6096 6097 .flags = 1*SD_LOAD_BALANCE 6098 | 1*SD_BALANCE_NEWIDLE 6099 | 1*SD_BALANCE_EXEC 6100 | 1*SD_BALANCE_FORK 6101 | 0*SD_BALANCE_WAKE 6102 | 1*SD_WAKE_AFFINE 6103 | 0*SD_SHARE_CPUCAPACITY 6104 | 0*SD_SHARE_PKG_RESOURCES 6105 | 0*SD_SERIALIZE 6106 | 0*SD_PREFER_SIBLING 6107 | 0*SD_NUMA 6108 | sd_flags 6109 , 6110 6111 .last_balance = jiffies, 6112 .balance_interval = sd_weight, 6113 .smt_gain = 0, 6114 .max_newidle_lb_cost = 0, 6115 .next_decay_max_lb_cost = jiffies, 6116#ifdef CONFIG_SCHED_DEBUG 6117 .name = tl->name, 6118#endif 6119 }; 6120 6121 /* 6122 * Convert topological properties into behaviour. 6123 */ 6124 6125 if (sd->flags & SD_SHARE_CPUCAPACITY) { 6126 sd->imbalance_pct = 110; 6127 sd->smt_gain = 1178; /* ~15% */ 6128 6129 } else if (sd->flags & SD_SHARE_PKG_RESOURCES) { 6130 sd->imbalance_pct = 117; 6131 sd->cache_nice_tries = 1; 6132 sd->busy_idx = 2; 6133 6134#ifdef CONFIG_NUMA 6135 } else if (sd->flags & SD_NUMA) { 6136 sd->cache_nice_tries = 2; 6137 sd->busy_idx = 3; 6138 sd->idle_idx = 2; 6139 6140 sd->flags |= SD_SERIALIZE; 6141 if (sched_domains_numa_distance[tl->numa_level] > RECLAIM_DISTANCE) { 6142 sd->flags &= ~(SD_BALANCE_EXEC | 6143 SD_BALANCE_FORK | 6144 SD_WAKE_AFFINE); 6145 } 6146 6147#endif 6148 } else { 6149 sd->flags |= SD_PREFER_SIBLING; 6150 sd->cache_nice_tries = 1; 6151 sd->busy_idx = 2; 6152 sd->idle_idx = 1; 6153 } 6154 6155 sd->private = &tl->data; 6156 6157 return sd; 6158} 6159 6160/* 6161 * Topology list, bottom-up. 6162 */ 6163static struct sched_domain_topology_level default_topology[] = { 6164#ifdef CONFIG_SCHED_SMT 6165 { cpu_smt_mask, cpu_smt_flags, SD_INIT_NAME(SMT) }, 6166#endif 6167#ifdef CONFIG_SCHED_MC 6168 { cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) }, 6169#endif 6170 { cpu_cpu_mask, SD_INIT_NAME(DIE) }, 6171 { NULL, }, 6172}; 6173 6174struct sched_domain_topology_level *sched_domain_topology = default_topology; 6175 6176#define for_each_sd_topology(tl) \ 6177 for (tl = sched_domain_topology; tl->mask; tl++) 6178 6179void set_sched_topology(struct sched_domain_topology_level *tl) 6180{ 6181 sched_domain_topology = tl; 6182} 6183 6184#ifdef CONFIG_NUMA 6185 6186static const struct cpumask *sd_numa_mask(int cpu) 6187{ 6188 return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)]; 6189} 6190 6191static void sched_numa_warn(const char *str) 6192{ 6193 static int done = false; 6194 int i,j; 6195 6196 if (done) 6197 return; 6198 6199 done = true; 6200 6201 printk(KERN_WARNING "ERROR: %s\n\n", str); 6202 6203 for (i = 0; i < nr_node_ids; i++) { 6204 printk(KERN_WARNING " "); 6205 for (j = 0; j < nr_node_ids; j++) 6206 printk(KERN_CONT "%02d ", node_distance(i,j)); 6207 printk(KERN_CONT "\n"); 6208 } 6209 printk(KERN_WARNING "\n"); 6210} 6211 6212static bool find_numa_distance(int distance) 6213{ 6214 int i; 6215 6216 if (distance == node_distance(0, 0)) 6217 return true; 6218 6219 for (i = 0; i < sched_domains_numa_levels; i++) { 6220 if (sched_domains_numa_distance[i] == distance) 6221 return true; 6222 } 6223 6224 return false; 6225} 6226 6227static void sched_init_numa(void) 6228{ 6229 int next_distance, curr_distance = node_distance(0, 0); 6230 struct sched_domain_topology_level *tl; 6231 int level = 0; 6232 int i, j, k; 6233 6234 sched_domains_numa_distance = kzalloc(sizeof(int) * nr_node_ids, GFP_KERNEL); 6235 if (!sched_domains_numa_distance) 6236 return; 6237 6238 /* 6239 * O(nr_nodes^2) deduplicating selection sort -- in order to find the 6240 * unique distances in the node_distance() table. 6241 * 6242 * Assumes node_distance(0,j) includes all distances in 6243 * node_distance(i,j) in order to avoid cubic time. 6244 */ 6245 next_distance = curr_distance; 6246 for (i = 0; i < nr_node_ids; i++) { 6247 for (j = 0; j < nr_node_ids; j++) { 6248 for (k = 0; k < nr_node_ids; k++) { 6249 int distance = node_distance(i, k); 6250 6251 if (distance > curr_distance && 6252 (distance < next_distance || 6253 next_distance == curr_distance)) 6254 next_distance = distance; 6255 6256 /* 6257 * While not a strong assumption it would be nice to know 6258 * about cases where if node A is connected to B, B is not 6259 * equally connected to A. 6260 */ 6261 if (sched_debug() && node_distance(k, i) != distance) 6262 sched_numa_warn("Node-distance not symmetric"); 6263 6264 if (sched_debug() && i && !find_numa_distance(distance)) 6265 sched_numa_warn("Node-0 not representative"); 6266 } 6267 if (next_distance != curr_distance) { 6268 sched_domains_numa_distance[level++] = next_distance; 6269 sched_domains_numa_levels = level; 6270 curr_distance = next_distance; 6271 } else break; 6272 } 6273 6274 /* 6275 * In case of sched_debug() we verify the above assumption. 6276 */ 6277 if (!sched_debug()) 6278 break; 6279 } 6280 /* 6281 * 'level' contains the number of unique distances, excluding the 6282 * identity distance node_distance(i,i). 6283 * 6284 * The sched_domains_numa_distance[] array includes the actual distance 6285 * numbers. 6286 */ 6287 6288 /* 6289 * Here, we should temporarily reset sched_domains_numa_levels to 0. 6290 * If it fails to allocate memory for array sched_domains_numa_masks[][], 6291 * the array will contain less then 'level' members. This could be 6292 * dangerous when we use it to iterate array sched_domains_numa_masks[][] 6293 * in other functions. 6294 * 6295 * We reset it to 'level' at the end of this function. 6296 */ 6297 sched_domains_numa_levels = 0; 6298 6299 sched_domains_numa_masks = kzalloc(sizeof(void *) * level, GFP_KERNEL); 6300 if (!sched_domains_numa_masks) 6301 return; 6302 6303 /* 6304 * Now for each level, construct a mask per node which contains all 6305 * cpus of nodes that are that many hops away from us. 6306 */ 6307 for (i = 0; i < level; i++) { 6308 sched_domains_numa_masks[i] = 6309 kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL); 6310 if (!sched_domains_numa_masks[i]) 6311 return; 6312 6313 for (j = 0; j < nr_node_ids; j++) { 6314 struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL); 6315 if (!mask) 6316 return; 6317 6318 sched_domains_numa_masks[i][j] = mask; 6319 6320 for (k = 0; k < nr_node_ids; k++) { 6321 if (node_distance(j, k) > sched_domains_numa_distance[i]) 6322 continue; 6323 6324 cpumask_or(mask, mask, cpumask_of_node(k)); 6325 } 6326 } 6327 } 6328 6329 /* Compute default topology size */ 6330 for (i = 0; sched_domain_topology[i].mask; i++); 6331 6332 tl = kzalloc((i + level + 1) * 6333 sizeof(struct sched_domain_topology_level), GFP_KERNEL); 6334 if (!tl) 6335 return; 6336 6337 /* 6338 * Copy the default topology bits.. 6339 */ 6340 for (i = 0; sched_domain_topology[i].mask; i++) 6341 tl[i] = sched_domain_topology[i]; 6342 6343 /* 6344 * .. and append 'j' levels of NUMA goodness. 6345 */ 6346 for (j = 0; j < level; i++, j++) { 6347 tl[i] = (struct sched_domain_topology_level){ 6348 .mask = sd_numa_mask, 6349 .sd_flags = cpu_numa_flags, 6350 .flags = SDTL_OVERLAP, 6351 .numa_level = j, 6352 SD_INIT_NAME(NUMA) 6353 }; 6354 } 6355 6356 sched_domain_topology = tl; 6357 6358 sched_domains_numa_levels = level; 6359} 6360 6361static void sched_domains_numa_masks_set(int cpu) 6362{ 6363 int i, j; 6364 int node = cpu_to_node(cpu); 6365 6366 for (i = 0; i < sched_domains_numa_levels; i++) { 6367 for (j = 0; j < nr_node_ids; j++) { 6368 if (node_distance(j, node) <= sched_domains_numa_distance[i]) 6369 cpumask_set_cpu(cpu, sched_domains_numa_masks[i][j]); 6370 } 6371 } 6372} 6373 6374static void sched_domains_numa_masks_clear(int cpu) 6375{ 6376 int i, j; 6377 for (i = 0; i < sched_domains_numa_levels; i++) { 6378 for (j = 0; j < nr_node_ids; j++) 6379 cpumask_clear_cpu(cpu, sched_domains_numa_masks[i][j]); 6380 } 6381} 6382 6383/* 6384 * Update sched_domains_numa_masks[level][node] array when new cpus 6385 * are onlined. 6386 */ 6387static int sched_domains_numa_masks_update(struct notifier_block *nfb, 6388 unsigned long action, 6389 void *hcpu) 6390{ 6391 int cpu = (long)hcpu; 6392 6393 switch (action & ~CPU_TASKS_FROZEN) { 6394 case CPU_ONLINE: 6395 sched_domains_numa_masks_set(cpu); 6396 break; 6397 6398 case CPU_DEAD: 6399 sched_domains_numa_masks_clear(cpu); 6400 break; 6401 6402 default: 6403 return NOTIFY_DONE; 6404 } 6405 6406 return NOTIFY_OK; 6407} 6408#else 6409static inline void sched_init_numa(void) 6410{ 6411} 6412 6413static int sched_domains_numa_masks_update(struct notifier_block *nfb, 6414 unsigned long action, 6415 void *hcpu) 6416{ 6417 return 0; 6418} 6419#endif /* CONFIG_NUMA */ 6420 6421static int __sdt_alloc(const struct cpumask *cpu_map) 6422{ 6423 struct sched_domain_topology_level *tl; 6424 int j; 6425 6426 for_each_sd_topology(tl) { 6427 struct sd_data *sdd = &tl->data; 6428 6429 sdd->sd = alloc_percpu(struct sched_domain *); 6430 if (!sdd->sd) 6431 return -ENOMEM; 6432 6433 sdd->sg = alloc_percpu(struct sched_group *); 6434 if (!sdd->sg) 6435 return -ENOMEM; 6436 6437 sdd->sgc = alloc_percpu(struct sched_group_capacity *); 6438 if (!sdd->sgc) 6439 return -ENOMEM; 6440 6441 for_each_cpu(j, cpu_map) { 6442 struct sched_domain *sd; 6443 struct sched_group *sg; 6444 struct sched_group_capacity *sgc; 6445 6446 sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(), 6447 GFP_KERNEL, cpu_to_node(j)); 6448 if (!sd) 6449 return -ENOMEM; 6450 6451 *per_cpu_ptr(sdd->sd, j) = sd; 6452 6453 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), 6454 GFP_KERNEL, cpu_to_node(j)); 6455 if (!sg) 6456 return -ENOMEM; 6457 6458 sg->next = sg; 6459 6460 *per_cpu_ptr(sdd->sg, j) = sg; 6461 6462 sgc = kzalloc_node(sizeof(struct sched_group_capacity) + cpumask_size(), 6463 GFP_KERNEL, cpu_to_node(j)); 6464 if (!sgc) 6465 return -ENOMEM; 6466 6467 *per_cpu_ptr(sdd->sgc, j) = sgc; 6468 } 6469 } 6470 6471 return 0; 6472} 6473 6474static void __sdt_free(const struct cpumask *cpu_map) 6475{ 6476 struct sched_domain_topology_level *tl; 6477 int j; 6478 6479 for_each_sd_topology(tl) { 6480 struct sd_data *sdd = &tl->data; 6481 6482 for_each_cpu(j, cpu_map) { 6483 struct sched_domain *sd; 6484 6485 if (sdd->sd) { 6486 sd = *per_cpu_ptr(sdd->sd, j); 6487 if (sd && (sd->flags & SD_OVERLAP)) 6488 free_sched_groups(sd->groups, 0); 6489 kfree(*per_cpu_ptr(sdd->sd, j)); 6490 } 6491 6492 if (sdd->sg) 6493 kfree(*per_cpu_ptr(sdd->sg, j)); 6494 if (sdd->sgc) 6495 kfree(*per_cpu_ptr(sdd->sgc, j)); 6496 } 6497 free_percpu(sdd->sd); 6498 sdd->sd = NULL; 6499 free_percpu(sdd->sg); 6500 sdd->sg = NULL; 6501 free_percpu(sdd->sgc); 6502 sdd->sgc = NULL; 6503 } 6504} 6505 6506struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl, 6507 const struct cpumask *cpu_map, struct sched_domain_attr *attr, 6508 struct sched_domain *child, int cpu) 6509{ 6510 struct sched_domain *sd = sd_init(tl, cpu); 6511 if (!sd) 6512 return child; 6513 6514 cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu)); 6515 if (child) { 6516 sd->level = child->level + 1; 6517 sched_domain_level_max = max(sched_domain_level_max, sd->level); 6518 child->parent = sd; 6519 sd->child = child; 6520 6521 if (!cpumask_subset(sched_domain_span(child), 6522 sched_domain_span(sd))) { 6523 pr_err("BUG: arch topology borken\n"); 6524#ifdef CONFIG_SCHED_DEBUG 6525 pr_err(" the %s domain not a subset of the %s domain\n", 6526 child->name, sd->name); 6527#endif 6528 /* Fixup, ensure @sd has at least @child cpus. */ 6529 cpumask_or(sched_domain_span(sd), 6530 sched_domain_span(sd), 6531 sched_domain_span(child)); 6532 } 6533 6534 } 6535 set_domain_attribute(sd, attr); 6536 6537 return sd; 6538} 6539 6540/* 6541 * Build sched domains for a given set of cpus and attach the sched domains 6542 * to the individual cpus 6543 */ 6544static int build_sched_domains(const struct cpumask *cpu_map, 6545 struct sched_domain_attr *attr) 6546{ 6547 enum s_alloc alloc_state; 6548 struct sched_domain *sd; 6549 struct s_data d; 6550 int i, ret = -ENOMEM; 6551 6552 alloc_state = __visit_domain_allocation_hell(&d, cpu_map); 6553 if (alloc_state != sa_rootdomain) 6554 goto error; 6555 6556 /* Set up domains for cpus specified by the cpu_map. */ 6557 for_each_cpu(i, cpu_map) { 6558 struct sched_domain_topology_level *tl; 6559 6560 sd = NULL; 6561 for_each_sd_topology(tl) { 6562 sd = build_sched_domain(tl, cpu_map, attr, sd, i); 6563 if (tl == sched_domain_topology) 6564 *per_cpu_ptr(d.sd, i) = sd; 6565 if (tl->flags & SDTL_OVERLAP || sched_feat(FORCE_SD_OVERLAP)) 6566 sd->flags |= SD_OVERLAP; 6567 if (cpumask_equal(cpu_map, sched_domain_span(sd))) 6568 break; 6569 } 6570 } 6571 6572 /* Build the groups for the domains */ 6573 for_each_cpu(i, cpu_map) { 6574 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { 6575 sd->span_weight = cpumask_weight(sched_domain_span(sd)); 6576 if (sd->flags & SD_OVERLAP) { 6577 if (build_overlap_sched_groups(sd, i)) 6578 goto error; 6579 } else { 6580 if (build_sched_groups(sd, i)) 6581 goto error; 6582 } 6583 } 6584 } 6585 6586 /* Calculate CPU capacity for physical packages and nodes */ 6587 for (i = nr_cpumask_bits-1; i >= 0; i--) { 6588 if (!cpumask_test_cpu(i, cpu_map)) 6589 continue; 6590 6591 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { 6592 claim_allocations(i, sd); 6593 init_sched_groups_capacity(i, sd); 6594 } 6595 } 6596 6597 /* Attach the domains */ 6598 rcu_read_lock(); 6599 for_each_cpu(i, cpu_map) { 6600 sd = *per_cpu_ptr(d.sd, i); 6601 cpu_attach_domain(sd, d.rd, i); 6602 } 6603 rcu_read_unlock(); 6604 6605 ret = 0; 6606error: 6607 __free_domain_allocs(&d, alloc_state, cpu_map); 6608 return ret; 6609} 6610 6611static cpumask_var_t *doms_cur; /* current sched domains */ 6612static int ndoms_cur; /* number of sched domains in 'doms_cur' */ 6613static struct sched_domain_attr *dattr_cur; 6614 /* attribues of custom domains in 'doms_cur' */ 6615 6616/* 6617 * Special case: If a kmalloc of a doms_cur partition (array of 6618 * cpumask) fails, then fallback to a single sched domain, 6619 * as determined by the single cpumask fallback_doms. 6620 */ 6621static cpumask_var_t fallback_doms; 6622 6623/* 6624 * arch_update_cpu_topology lets virtualized architectures update the 6625 * cpu core maps. It is supposed to return 1 if the topology changed 6626 * or 0 if it stayed the same. 6627 */ 6628int __weak arch_update_cpu_topology(void) 6629{ 6630 return 0; 6631} 6632 6633cpumask_var_t *alloc_sched_domains(unsigned int ndoms) 6634{ 6635 int i; 6636 cpumask_var_t *doms; 6637 6638 doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL); 6639 if (!doms) 6640 return NULL; 6641 for (i = 0; i < ndoms; i++) { 6642 if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) { 6643 free_sched_domains(doms, i); 6644 return NULL; 6645 } 6646 } 6647 return doms; 6648} 6649 6650void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms) 6651{ 6652 unsigned int i; 6653 for (i = 0; i < ndoms; i++) 6654 free_cpumask_var(doms[i]); 6655 kfree(doms); 6656} 6657 6658/* 6659 * Set up scheduler domains and groups. Callers must hold the hotplug lock. 6660 * For now this just excludes isolated cpus, but could be used to 6661 * exclude other special cases in the future. 6662 */ 6663static int init_sched_domains(const struct cpumask *cpu_map) 6664{ 6665 int err; 6666 6667 arch_update_cpu_topology(); 6668 ndoms_cur = 1; 6669 doms_cur = alloc_sched_domains(ndoms_cur); 6670 if (!doms_cur) 6671 doms_cur = &fallback_doms; 6672 cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map); 6673 err = build_sched_domains(doms_cur[0], NULL); 6674 register_sched_domain_sysctl(); 6675 6676 return err; 6677} 6678 6679/* 6680 * Detach sched domains from a group of cpus specified in cpu_map 6681 * These cpus will now be attached to the NULL domain 6682 */ 6683static void detach_destroy_domains(const struct cpumask *cpu_map) 6684{ 6685 int i; 6686 6687 rcu_read_lock(); 6688 for_each_cpu(i, cpu_map) 6689 cpu_attach_domain(NULL, &def_root_domain, i); 6690 rcu_read_unlock(); 6691} 6692 6693/* handle null as "default" */ 6694static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur, 6695 struct sched_domain_attr *new, int idx_new) 6696{ 6697 struct sched_domain_attr tmp; 6698 6699 /* fast path */ 6700 if (!new && !cur) 6701 return 1; 6702 6703 tmp = SD_ATTR_INIT; 6704 return !memcmp(cur ? (cur + idx_cur) : &tmp, 6705 new ? (new + idx_new) : &tmp, 6706 sizeof(struct sched_domain_attr)); 6707} 6708 6709/* 6710 * Partition sched domains as specified by the 'ndoms_new' 6711 * cpumasks in the array doms_new[] of cpumasks. This compares 6712 * doms_new[] to the current sched domain partitioning, doms_cur[]. 6713 * It destroys each deleted domain and builds each new domain. 6714 * 6715 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'. 6716 * The masks don't intersect (don't overlap.) We should setup one 6717 * sched domain for each mask. CPUs not in any of the cpumasks will 6718 * not be load balanced. If the same cpumask appears both in the 6719 * current 'doms_cur' domains and in the new 'doms_new', we can leave 6720 * it as it is. 6721 * 6722 * The passed in 'doms_new' should be allocated using 6723 * alloc_sched_domains. This routine takes ownership of it and will 6724 * free_sched_domains it when done with it. If the caller failed the 6725 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1, 6726 * and partition_sched_domains() will fallback to the single partition 6727 * 'fallback_doms', it also forces the domains to be rebuilt. 6728 * 6729 * If doms_new == NULL it will be replaced with cpu_online_mask. 6730 * ndoms_new == 0 is a special case for destroying existing domains, 6731 * and it will not create the default domain. 6732 * 6733 * Call with hotplug lock held 6734 */ 6735void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[], 6736 struct sched_domain_attr *dattr_new) 6737{ 6738 int i, j, n; 6739 int new_topology; 6740 6741 mutex_lock(&sched_domains_mutex); 6742 6743 /* always unregister in case we don't destroy any domains */ 6744 unregister_sched_domain_sysctl(); 6745 6746 /* Let architecture update cpu core mappings. */ 6747 new_topology = arch_update_cpu_topology(); 6748 6749 n = doms_new ? ndoms_new : 0; 6750 6751 /* Destroy deleted domains */ 6752 for (i = 0; i < ndoms_cur; i++) { 6753 for (j = 0; j < n && !new_topology; j++) { 6754 if (cpumask_equal(doms_cur[i], doms_new[j]) 6755 && dattrs_equal(dattr_cur, i, dattr_new, j)) 6756 goto match1; 6757 } 6758 /* no match - a current sched domain not in new doms_new[] */ 6759 detach_destroy_domains(doms_cur[i]); 6760match1: 6761 ; 6762 } 6763 6764 n = ndoms_cur; 6765 if (doms_new == NULL) { 6766 n = 0; 6767 doms_new = &fallback_doms; 6768 cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map); 6769 WARN_ON_ONCE(dattr_new); 6770 } 6771 6772 /* Build new domains */ 6773 for (i = 0; i < ndoms_new; i++) { 6774 for (j = 0; j < n && !new_topology; j++) { 6775 if (cpumask_equal(doms_new[i], doms_cur[j]) 6776 && dattrs_equal(dattr_new, i, dattr_cur, j)) 6777 goto match2; 6778 } 6779 /* no match - add a new doms_new */ 6780 build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL); 6781match2: 6782 ; 6783 } 6784 6785 /* Remember the new sched domains */ 6786 if (doms_cur != &fallback_doms) 6787 free_sched_domains(doms_cur, ndoms_cur); 6788 kfree(dattr_cur); /* kfree(NULL) is safe */ 6789 doms_cur = doms_new; 6790 dattr_cur = dattr_new; 6791 ndoms_cur = ndoms_new; 6792 6793 register_sched_domain_sysctl(); 6794 6795 mutex_unlock(&sched_domains_mutex); 6796} 6797 6798static int num_cpus_frozen; /* used to mark begin/end of suspend/resume */ 6799 6800/* 6801 * Update cpusets according to cpu_active mask. If cpusets are 6802 * disabled, cpuset_update_active_cpus() becomes a simple wrapper 6803 * around partition_sched_domains(). 6804 * 6805 * If we come here as part of a suspend/resume, don't touch cpusets because we 6806 * want to restore it back to its original state upon resume anyway. 6807 */ 6808static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action, 6809 void *hcpu) 6810{ 6811 switch (action) { 6812 case CPU_ONLINE_FROZEN: 6813 case CPU_DOWN_FAILED_FROZEN: 6814 6815 /* 6816 * num_cpus_frozen tracks how many CPUs are involved in suspend 6817 * resume sequence. As long as this is not the last online 6818 * operation in the resume sequence, just build a single sched 6819 * domain, ignoring cpusets. 6820 */ 6821 num_cpus_frozen--; 6822 if (likely(num_cpus_frozen)) { 6823 partition_sched_domains(1, NULL, NULL); 6824 break; 6825 } 6826 6827 /* 6828 * This is the last CPU online operation. So fall through and 6829 * restore the original sched domains by considering the 6830 * cpuset configurations. 6831 */ 6832 6833 case CPU_ONLINE: 6834 case CPU_DOWN_FAILED: 6835 cpuset_update_active_cpus(true); 6836 break; 6837 default: 6838 return NOTIFY_DONE; 6839 } 6840 return NOTIFY_OK; 6841} 6842 6843static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action, 6844 void *hcpu) 6845{ 6846 switch (action) { 6847 case CPU_DOWN_PREPARE: 6848 cpuset_update_active_cpus(false); 6849 break; 6850 case CPU_DOWN_PREPARE_FROZEN: 6851 num_cpus_frozen++; 6852 partition_sched_domains(1, NULL, NULL); 6853 break; 6854 default: 6855 return NOTIFY_DONE; 6856 } 6857 return NOTIFY_OK; 6858} 6859 6860void __init sched_init_smp(void) 6861{ 6862 cpumask_var_t non_isolated_cpus; 6863 6864 alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL); 6865 alloc_cpumask_var(&fallback_doms, GFP_KERNEL); 6866 6867 sched_init_numa(); 6868 6869 /* 6870 * There's no userspace yet to cause hotplug operations; hence all the 6871 * cpu masks are stable and all blatant races in the below code cannot 6872 * happen. 6873 */ 6874 mutex_lock(&sched_domains_mutex); 6875 init_sched_domains(cpu_active_mask); 6876 cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map); 6877 if (cpumask_empty(non_isolated_cpus)) 6878 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus); 6879 mutex_unlock(&sched_domains_mutex); 6880 6881 hotcpu_notifier(sched_domains_numa_masks_update, CPU_PRI_SCHED_ACTIVE); 6882 hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE); 6883 hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE); 6884 6885 init_hrtick(); 6886 6887 /* Move init over to a non-isolated CPU */ 6888 if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0) 6889 BUG(); 6890 sched_init_granularity(); 6891 free_cpumask_var(non_isolated_cpus); 6892 6893 init_sched_rt_class(); 6894 init_sched_dl_class(); 6895} 6896#else 6897void __init sched_init_smp(void) 6898{ 6899 sched_init_granularity(); 6900} 6901#endif /* CONFIG_SMP */ 6902 6903const_debug unsigned int sysctl_timer_migration = 1; 6904 6905int in_sched_functions(unsigned long addr) 6906{ 6907 return in_lock_functions(addr) || 6908 (addr >= (unsigned long)__sched_text_start 6909 && addr < (unsigned long)__sched_text_end); 6910} 6911 6912#ifdef CONFIG_CGROUP_SCHED 6913/* 6914 * Default task group. 6915 * Every task in system belongs to this group at bootup. 6916 */ 6917struct task_group root_task_group; 6918LIST_HEAD(task_groups); 6919#endif 6920 6921DECLARE_PER_CPU(cpumask_var_t, load_balance_mask); 6922 6923void __init sched_init(void) 6924{ 6925 int i, j; 6926 unsigned long alloc_size = 0, ptr; 6927 6928#ifdef CONFIG_FAIR_GROUP_SCHED 6929 alloc_size += 2 * nr_cpu_ids * sizeof(void **); 6930#endif 6931#ifdef CONFIG_RT_GROUP_SCHED 6932 alloc_size += 2 * nr_cpu_ids * sizeof(void **); 6933#endif 6934#ifdef CONFIG_CPUMASK_OFFSTACK 6935 alloc_size += num_possible_cpus() * cpumask_size(); 6936#endif 6937 if (alloc_size) { 6938 ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT); 6939 6940#ifdef CONFIG_FAIR_GROUP_SCHED 6941 root_task_group.se = (struct sched_entity **)ptr; 6942 ptr += nr_cpu_ids * sizeof(void **); 6943 6944 root_task_group.cfs_rq = (struct cfs_rq **)ptr; 6945 ptr += nr_cpu_ids * sizeof(void **); 6946 6947#endif /* CONFIG_FAIR_GROUP_SCHED */ 6948#ifdef CONFIG_RT_GROUP_SCHED 6949 root_task_group.rt_se = (struct sched_rt_entity **)ptr; 6950 ptr += nr_cpu_ids * sizeof(void **); 6951 6952 root_task_group.rt_rq = (struct rt_rq **)ptr; 6953 ptr += nr_cpu_ids * sizeof(void **); 6954 6955#endif /* CONFIG_RT_GROUP_SCHED */ 6956#ifdef CONFIG_CPUMASK_OFFSTACK 6957 for_each_possible_cpu(i) { 6958 per_cpu(load_balance_mask, i) = (void *)ptr; 6959 ptr += cpumask_size(); 6960 } 6961#endif /* CONFIG_CPUMASK_OFFSTACK */ 6962 } 6963 6964 init_rt_bandwidth(&def_rt_bandwidth, 6965 global_rt_period(), global_rt_runtime()); 6966 init_dl_bandwidth(&def_dl_bandwidth, 6967 global_rt_period(), global_rt_runtime()); 6968 6969#ifdef CONFIG_SMP 6970 init_defrootdomain(); 6971#endif 6972 6973#ifdef CONFIG_RT_GROUP_SCHED 6974 init_rt_bandwidth(&root_task_group.rt_bandwidth, 6975 global_rt_period(), global_rt_runtime()); 6976#endif /* CONFIG_RT_GROUP_SCHED */ 6977 6978#ifdef CONFIG_CGROUP_SCHED 6979 list_add(&root_task_group.list, &task_groups); 6980 INIT_LIST_HEAD(&root_task_group.children); 6981 INIT_LIST_HEAD(&root_task_group.siblings); 6982 autogroup_init(&init_task); 6983 6984#endif /* CONFIG_CGROUP_SCHED */ 6985 6986 for_each_possible_cpu(i) { 6987 struct rq *rq; 6988 6989 rq = cpu_rq(i); 6990 raw_spin_lock_init(&rq->lock); 6991 rq->nr_running = 0; 6992 rq->calc_load_active = 0; 6993 rq->calc_load_update = jiffies + LOAD_FREQ; 6994 init_cfs_rq(&rq->cfs); 6995 init_rt_rq(&rq->rt, rq); 6996 init_dl_rq(&rq->dl, rq); 6997#ifdef CONFIG_FAIR_GROUP_SCHED 6998 root_task_group.shares = ROOT_TASK_GROUP_LOAD; 6999 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list); 7000 /* 7001 * How much cpu bandwidth does root_task_group get? 7002 * 7003 * In case of task-groups formed thr' the cgroup filesystem, it 7004 * gets 100% of the cpu resources in the system. This overall 7005 * system cpu resource is divided among the tasks of 7006 * root_task_group and its child task-groups in a fair manner, 7007 * based on each entity's (task or task-group's) weight 7008 * (se->load.weight). 7009 * 7010 * In other words, if root_task_group has 10 tasks of weight 7011 * 1024) and two child groups A0 and A1 (of weight 1024 each), 7012 * then A0's share of the cpu resource is: 7013 * 7014 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33% 7015 * 7016 * We achieve this by letting root_task_group's tasks sit 7017 * directly in rq->cfs (i.e root_task_group->se[] = NULL). 7018 */ 7019 init_cfs_bandwidth(&root_task_group.cfs_bandwidth); 7020 init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL); 7021#endif /* CONFIG_FAIR_GROUP_SCHED */ 7022 7023 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime; 7024#ifdef CONFIG_RT_GROUP_SCHED 7025 init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL); 7026#endif 7027 7028 for (j = 0; j < CPU_LOAD_IDX_MAX; j++) 7029 rq->cpu_load[j] = 0; 7030 7031 rq->last_load_update_tick = jiffies; 7032 7033#ifdef CONFIG_SMP 7034 rq->sd = NULL; 7035 rq->rd = NULL; 7036 rq->cpu_capacity = SCHED_CAPACITY_SCALE; 7037 rq->post_schedule = 0; 7038 rq->active_balance = 0; 7039 rq->next_balance = jiffies; 7040 rq->push_cpu = 0; 7041 rq->cpu = i; 7042 rq->online = 0; 7043 rq->idle_stamp = 0; 7044 rq->avg_idle = 2*sysctl_sched_migration_cost; 7045 rq->max_idle_balance_cost = sysctl_sched_migration_cost; 7046 7047 INIT_LIST_HEAD(&rq->cfs_tasks); 7048 7049 rq_attach_root(rq, &def_root_domain); 7050#ifdef CONFIG_NO_HZ_COMMON 7051 rq->nohz_flags = 0; 7052#endif 7053#ifdef CONFIG_NO_HZ_FULL 7054 rq->last_sched_tick = 0; 7055#endif 7056#endif 7057 init_rq_hrtick(rq); 7058 atomic_set(&rq->nr_iowait, 0); 7059 } 7060 7061 set_load_weight(&init_task); 7062 7063#ifdef CONFIG_PREEMPT_NOTIFIERS 7064 INIT_HLIST_HEAD(&init_task.preempt_notifiers); 7065#endif 7066 7067 /* 7068 * The boot idle thread does lazy MMU switching as well: 7069 */ 7070 atomic_inc(&init_mm.mm_count); 7071 enter_lazy_tlb(&init_mm, current); 7072 7073 /* 7074 * Make us the idle thread. Technically, schedule() should not be 7075 * called from this thread, however somewhere below it might be, 7076 * but because we are the idle thread, we just pick up running again 7077 * when this runqueue becomes "idle". 7078 */ 7079 init_idle(current, smp_processor_id()); 7080 7081 calc_load_update = jiffies + LOAD_FREQ; 7082 7083 /* 7084 * During early bootup we pretend to be a normal task: 7085 */ 7086 current->sched_class = &fair_sched_class; 7087 7088#ifdef CONFIG_SMP 7089 zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT); 7090 /* May be allocated at isolcpus cmdline parse time */ 7091 if (cpu_isolated_map == NULL) 7092 zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT); 7093 idle_thread_set_boot_cpu(); 7094 set_cpu_rq_start_time(); 7095#endif 7096 init_sched_fair_class(); 7097 7098 scheduler_running = 1; 7099} 7100 7101#ifdef CONFIG_DEBUG_ATOMIC_SLEEP 7102static inline int preempt_count_equals(int preempt_offset) 7103{ 7104 int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth(); 7105 7106 return (nested == preempt_offset); 7107} 7108 7109void __might_sleep(const char *file, int line, int preempt_offset) 7110{ 7111 static unsigned long prev_jiffy; /* ratelimiting */ 7112 7113 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */ 7114 if ((preempt_count_equals(preempt_offset) && !irqs_disabled() && 7115 !is_idle_task(current)) || 7116 system_state != SYSTEM_RUNNING || oops_in_progress) 7117 return; 7118 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) 7119 return; 7120 prev_jiffy = jiffies; 7121 7122 printk(KERN_ERR 7123 "BUG: sleeping function called from invalid context at %s:%d\n", 7124 file, line); 7125 printk(KERN_ERR 7126 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n", 7127 in_atomic(), irqs_disabled(), 7128 current->pid, current->comm); 7129 7130 debug_show_held_locks(current); 7131 if (irqs_disabled()) 7132 print_irqtrace_events(current); 7133#ifdef CONFIG_DEBUG_PREEMPT 7134 if (!preempt_count_equals(preempt_offset)) { 7135 pr_err("Preemption disabled at:"); 7136 print_ip_sym(current->preempt_disable_ip); 7137 pr_cont("\n"); 7138 } 7139#endif 7140 dump_stack(); 7141} 7142EXPORT_SYMBOL(__might_sleep); 7143#endif 7144 7145#ifdef CONFIG_MAGIC_SYSRQ 7146static void normalize_task(struct rq *rq, struct task_struct *p) 7147{ 7148 const struct sched_class *prev_class = p->sched_class; 7149 struct sched_attr attr = { 7150 .sched_policy = SCHED_NORMAL, 7151 }; 7152 int old_prio = p->prio; 7153 int queued; 7154 7155 queued = task_on_rq_queued(p); 7156 if (queued) 7157 dequeue_task(rq, p, 0); 7158 __setscheduler(rq, p, &attr); 7159 if (queued) { 7160 enqueue_task(rq, p, 0); 7161 resched_curr(rq); 7162 } 7163 7164 check_class_changed(rq, p, prev_class, old_prio); 7165} 7166 7167void normalize_rt_tasks(void) 7168{ 7169 struct task_struct *g, *p; 7170 unsigned long flags; 7171 struct rq *rq; 7172 7173 read_lock_irqsave(&tasklist_lock, flags); 7174 for_each_process_thread(g, p) { 7175 /* 7176 * Only normalize user tasks: 7177 */ 7178 if (!p->mm) 7179 continue; 7180 7181 p->se.exec_start = 0; 7182#ifdef CONFIG_SCHEDSTATS 7183 p->se.statistics.wait_start = 0; 7184 p->se.statistics.sleep_start = 0; 7185 p->se.statistics.block_start = 0; 7186#endif 7187 7188 if (!dl_task(p) && !rt_task(p)) { 7189 /* 7190 * Renice negative nice level userspace 7191 * tasks back to 0: 7192 */ 7193 if (task_nice(p) < 0 && p->mm) 7194 set_user_nice(p, 0); 7195 continue; 7196 } 7197 7198 raw_spin_lock(&p->pi_lock); 7199 rq = __task_rq_lock(p); 7200 7201 normalize_task(rq, p); 7202 7203 __task_rq_unlock(rq); 7204 raw_spin_unlock(&p->pi_lock); 7205 } 7206 read_unlock_irqrestore(&tasklist_lock, flags); 7207} 7208 7209#endif /* CONFIG_MAGIC_SYSRQ */ 7210 7211#if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) 7212/* 7213 * These functions are only useful for the IA64 MCA handling, or kdb. 7214 * 7215 * They can only be called when the whole system has been 7216 * stopped - every CPU needs to be quiescent, and no scheduling 7217 * activity can take place. Using them for anything else would 7218 * be a serious bug, and as a result, they aren't even visible 7219 * under any other configuration. 7220 */ 7221 7222/** 7223 * curr_task - return the current task for a given cpu. 7224 * @cpu: the processor in question. 7225 * 7226 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! 7227 * 7228 * Return: The current task for @cpu. 7229 */ 7230struct task_struct *curr_task(int cpu) 7231{ 7232 return cpu_curr(cpu); 7233} 7234 7235#endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */ 7236 7237#ifdef CONFIG_IA64 7238/** 7239 * set_curr_task - set the current task for a given cpu. 7240 * @cpu: the processor in question. 7241 * @p: the task pointer to set. 7242 * 7243 * Description: This function must only be used when non-maskable interrupts 7244 * are serviced on a separate stack. It allows the architecture to switch the 7245 * notion of the current task on a cpu in a non-blocking manner. This function 7246 * must be called with all CPU's synchronized, and interrupts disabled, the 7247 * and caller must save the original value of the current task (see 7248 * curr_task() above) and restore that value before reenabling interrupts and 7249 * re-starting the system. 7250 * 7251 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! 7252 */ 7253void set_curr_task(int cpu, struct task_struct *p) 7254{ 7255 cpu_curr(cpu) = p; 7256} 7257 7258#endif 7259 7260#ifdef CONFIG_CGROUP_SCHED 7261/* task_group_lock serializes the addition/removal of task groups */ 7262static DEFINE_SPINLOCK(task_group_lock); 7263 7264static void free_sched_group(struct task_group *tg) 7265{ 7266 free_fair_sched_group(tg); 7267 free_rt_sched_group(tg); 7268 autogroup_free(tg); 7269 kfree(tg); 7270} 7271 7272/* allocate runqueue etc for a new task group */ 7273struct task_group *sched_create_group(struct task_group *parent) 7274{ 7275 struct task_group *tg; 7276 7277 tg = kzalloc(sizeof(*tg), GFP_KERNEL); 7278 if (!tg) 7279 return ERR_PTR(-ENOMEM); 7280 7281 if (!alloc_fair_sched_group(tg, parent)) 7282 goto err; 7283 7284 if (!alloc_rt_sched_group(tg, parent)) 7285 goto err; 7286 7287 return tg; 7288 7289err: 7290 free_sched_group(tg); 7291 return ERR_PTR(-ENOMEM); 7292} 7293 7294void sched_online_group(struct task_group *tg, struct task_group *parent) 7295{ 7296 unsigned long flags; 7297 7298 spin_lock_irqsave(&task_group_lock, flags); 7299 list_add_rcu(&tg->list, &task_groups); 7300 7301 WARN_ON(!parent); /* root should already exist */ 7302 7303 tg->parent = parent; 7304 INIT_LIST_HEAD(&tg->children); 7305 list_add_rcu(&tg->siblings, &parent->children); 7306 spin_unlock_irqrestore(&task_group_lock, flags); 7307} 7308 7309/* rcu callback to free various structures associated with a task group */ 7310static void free_sched_group_rcu(struct rcu_head *rhp) 7311{ 7312 /* now it should be safe to free those cfs_rqs */ 7313 free_sched_group(container_of(rhp, struct task_group, rcu)); 7314} 7315 7316/* Destroy runqueue etc associated with a task group */ 7317void sched_destroy_group(struct task_group *tg) 7318{ 7319 /* wait for possible concurrent references to cfs_rqs complete */ 7320 call_rcu(&tg->rcu, free_sched_group_rcu); 7321} 7322 7323void sched_offline_group(struct task_group *tg) 7324{ 7325 unsigned long flags; 7326 int i; 7327 7328 /* end participation in shares distribution */ 7329 for_each_possible_cpu(i) 7330 unregister_fair_sched_group(tg, i); 7331 7332 spin_lock_irqsave(&task_group_lock, flags); 7333 list_del_rcu(&tg->list); 7334 list_del_rcu(&tg->siblings); 7335 spin_unlock_irqrestore(&task_group_lock, flags); 7336} 7337 7338/* change task's runqueue when it moves between groups. 7339 * The caller of this function should have put the task in its new group 7340 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to 7341 * reflect its new group. 7342 */ 7343void sched_move_task(struct task_struct *tsk) 7344{ 7345 struct task_group *tg; 7346 int queued, running; 7347 unsigned long flags; 7348 struct rq *rq; 7349 7350 rq = task_rq_lock(tsk, &flags); 7351 7352 running = task_current(rq, tsk); 7353 queued = task_on_rq_queued(tsk); 7354 7355 if (queued) 7356 dequeue_task(rq, tsk, 0); 7357 if (unlikely(running)) 7358 tsk->sched_class->put_prev_task(rq, tsk); 7359 7360 tg = container_of(task_css_check(tsk, cpu_cgrp_id, 7361 lockdep_is_held(&tsk->sighand->siglock)), 7362 struct task_group, css); 7363 tg = autogroup_task_group(tsk, tg); 7364 tsk->sched_task_group = tg; 7365 7366#ifdef CONFIG_FAIR_GROUP_SCHED 7367 if (tsk->sched_class->task_move_group) 7368 tsk->sched_class->task_move_group(tsk, queued); 7369 else 7370#endif 7371 set_task_rq(tsk, task_cpu(tsk)); 7372 7373 if (unlikely(running)) 7374 tsk->sched_class->set_curr_task(rq); 7375 if (queued) 7376 enqueue_task(rq, tsk, 0); 7377 7378 task_rq_unlock(rq, tsk, &flags); 7379} 7380#endif /* CONFIG_CGROUP_SCHED */ 7381 7382#ifdef CONFIG_RT_GROUP_SCHED 7383/* 7384 * Ensure that the real time constraints are schedulable. 7385 */ 7386static DEFINE_MUTEX(rt_constraints_mutex); 7387 7388/* Must be called with tasklist_lock held */ 7389static inline int tg_has_rt_tasks(struct task_group *tg) 7390{ 7391 struct task_struct *g, *p; 7392 7393 for_each_process_thread(g, p) { 7394 if (rt_task(p) && task_rq(p)->rt.tg == tg) 7395 return 1; 7396 } 7397 7398 return 0; 7399} 7400 7401struct rt_schedulable_data { 7402 struct task_group *tg; 7403 u64 rt_period; 7404 u64 rt_runtime; 7405}; 7406 7407static int tg_rt_schedulable(struct task_group *tg, void *data) 7408{ 7409 struct rt_schedulable_data *d = data; 7410 struct task_group *child; 7411 unsigned long total, sum = 0; 7412 u64 period, runtime; 7413 7414 period = ktime_to_ns(tg->rt_bandwidth.rt_period); 7415 runtime = tg->rt_bandwidth.rt_runtime; 7416 7417 if (tg == d->tg) { 7418 period = d->rt_period; 7419 runtime = d->rt_runtime; 7420 } 7421 7422 /* 7423 * Cannot have more runtime than the period. 7424 */ 7425 if (runtime > period && runtime != RUNTIME_INF) 7426 return -EINVAL; 7427 7428 /* 7429 * Ensure we don't starve existing RT tasks. 7430 */ 7431 if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg)) 7432 return -EBUSY; 7433 7434 total = to_ratio(period, runtime); 7435 7436 /* 7437 * Nobody can have more than the global setting allows. 7438 */ 7439 if (total > to_ratio(global_rt_period(), global_rt_runtime())) 7440 return -EINVAL; 7441 7442 /* 7443 * The sum of our children's runtime should not exceed our own. 7444 */ 7445 list_for_each_entry_rcu(child, &tg->children, siblings) { 7446 period = ktime_to_ns(child->rt_bandwidth.rt_period); 7447 runtime = child->rt_bandwidth.rt_runtime; 7448 7449 if (child == d->tg) { 7450 period = d->rt_period; 7451 runtime = d->rt_runtime; 7452 } 7453 7454 sum += to_ratio(period, runtime); 7455 } 7456 7457 if (sum > total) 7458 return -EINVAL; 7459 7460 return 0; 7461} 7462 7463static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime) 7464{ 7465 int ret; 7466 7467 struct rt_schedulable_data data = { 7468 .tg = tg, 7469 .rt_period = period, 7470 .rt_runtime = runtime, 7471 }; 7472 7473 rcu_read_lock(); 7474 ret = walk_tg_tree(tg_rt_schedulable, tg_nop, &data); 7475 rcu_read_unlock(); 7476 7477 return ret; 7478} 7479 7480static int tg_set_rt_bandwidth(struct task_group *tg, 7481 u64 rt_period, u64 rt_runtime) 7482{ 7483 int i, err = 0; 7484 7485 mutex_lock(&rt_constraints_mutex); 7486 read_lock(&tasklist_lock); 7487 err = __rt_schedulable(tg, rt_period, rt_runtime); 7488 if (err) 7489 goto unlock; 7490 7491 raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock); 7492 tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period); 7493 tg->rt_bandwidth.rt_runtime = rt_runtime; 7494 7495 for_each_possible_cpu(i) { 7496 struct rt_rq *rt_rq = tg->rt_rq[i]; 7497 7498 raw_spin_lock(&rt_rq->rt_runtime_lock); 7499 rt_rq->rt_runtime = rt_runtime; 7500 raw_spin_unlock(&rt_rq->rt_runtime_lock); 7501 } 7502 raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock); 7503unlock: 7504 read_unlock(&tasklist_lock); 7505 mutex_unlock(&rt_constraints_mutex); 7506 7507 return err; 7508} 7509 7510static int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us) 7511{ 7512 u64 rt_runtime, rt_period; 7513 7514 rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period); 7515 rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC; 7516 if (rt_runtime_us < 0) 7517 rt_runtime = RUNTIME_INF; 7518 7519 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); 7520} 7521 7522static long sched_group_rt_runtime(struct task_group *tg) 7523{ 7524 u64 rt_runtime_us; 7525 7526 if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF) 7527 return -1; 7528 7529 rt_runtime_us = tg->rt_bandwidth.rt_runtime; 7530 do_div(rt_runtime_us, NSEC_PER_USEC); 7531 return rt_runtime_us; 7532} 7533 7534static int sched_group_set_rt_period(struct task_group *tg, long rt_period_us) 7535{ 7536 u64 rt_runtime, rt_period; 7537 7538 rt_period = (u64)rt_period_us * NSEC_PER_USEC; 7539 rt_runtime = tg->rt_bandwidth.rt_runtime; 7540 7541 if (rt_period == 0) 7542 return -EINVAL; 7543 7544 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); 7545} 7546 7547static long sched_group_rt_period(struct task_group *tg) 7548{ 7549 u64 rt_period_us; 7550 7551 rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period); 7552 do_div(rt_period_us, NSEC_PER_USEC); 7553 return rt_period_us; 7554} 7555#endif /* CONFIG_RT_GROUP_SCHED */ 7556 7557#ifdef CONFIG_RT_GROUP_SCHED 7558static int sched_rt_global_constraints(void) 7559{ 7560 int ret = 0; 7561 7562 mutex_lock(&rt_constraints_mutex); 7563 read_lock(&tasklist_lock); 7564 ret = __rt_schedulable(NULL, 0, 0); 7565 read_unlock(&tasklist_lock); 7566 mutex_unlock(&rt_constraints_mutex); 7567 7568 return ret; 7569} 7570 7571static int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk) 7572{ 7573 /* Don't accept realtime tasks when there is no way for them to run */ 7574 if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0) 7575 return 0; 7576 7577 return 1; 7578} 7579 7580#else /* !CONFIG_RT_GROUP_SCHED */ 7581static int sched_rt_global_constraints(void) 7582{ 7583 unsigned long flags; 7584 int i, ret = 0; 7585 7586 raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags); 7587 for_each_possible_cpu(i) { 7588 struct rt_rq *rt_rq = &cpu_rq(i)->rt; 7589 7590 raw_spin_lock(&rt_rq->rt_runtime_lock); 7591 rt_rq->rt_runtime = global_rt_runtime(); 7592 raw_spin_unlock(&rt_rq->rt_runtime_lock); 7593 } 7594 raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags); 7595 7596 return ret; 7597} 7598#endif /* CONFIG_RT_GROUP_SCHED */ 7599 7600static int sched_dl_global_constraints(void) 7601{ 7602 u64 runtime = global_rt_runtime(); 7603 u64 period = global_rt_period(); 7604 u64 new_bw = to_ratio(period, runtime); 7605 int cpu, ret = 0; 7606 unsigned long flags; 7607 7608 /* 7609 * Here we want to check the bandwidth not being set to some 7610 * value smaller than the currently allocated bandwidth in 7611 * any of the root_domains. 7612 * 7613 * FIXME: Cycling on all the CPUs is overdoing, but simpler than 7614 * cycling on root_domains... Discussion on different/better 7615 * solutions is welcome! 7616 */ 7617 for_each_possible_cpu(cpu) { 7618 struct dl_bw *dl_b = dl_bw_of(cpu); 7619 7620 raw_spin_lock_irqsave(&dl_b->lock, flags); 7621 if (new_bw < dl_b->total_bw) 7622 ret = -EBUSY; 7623 raw_spin_unlock_irqrestore(&dl_b->lock, flags); 7624 7625 if (ret) 7626 break; 7627 } 7628 7629 return ret; 7630} 7631 7632static void sched_dl_do_global(void) 7633{ 7634 u64 new_bw = -1; 7635 int cpu; 7636 unsigned long flags; 7637 7638 def_dl_bandwidth.dl_period = global_rt_period(); 7639 def_dl_bandwidth.dl_runtime = global_rt_runtime(); 7640 7641 if (global_rt_runtime() != RUNTIME_INF) 7642 new_bw = to_ratio(global_rt_period(), global_rt_runtime()); 7643 7644 /* 7645 * FIXME: As above... 7646 */ 7647 for_each_possible_cpu(cpu) { 7648 struct dl_bw *dl_b = dl_bw_of(cpu); 7649 7650 raw_spin_lock_irqsave(&dl_b->lock, flags); 7651 dl_b->bw = new_bw; 7652 raw_spin_unlock_irqrestore(&dl_b->lock, flags); 7653 } 7654} 7655 7656static int sched_rt_global_validate(void) 7657{ 7658 if (sysctl_sched_rt_period <= 0) 7659 return -EINVAL; 7660 7661 if ((sysctl_sched_rt_runtime != RUNTIME_INF) && 7662 (sysctl_sched_rt_runtime > sysctl_sched_rt_period)) 7663 return -EINVAL; 7664 7665 return 0; 7666} 7667 7668static void sched_rt_do_global(void) 7669{ 7670 def_rt_bandwidth.rt_runtime = global_rt_runtime(); 7671 def_rt_bandwidth.rt_period = ns_to_ktime(global_rt_period()); 7672} 7673 7674int sched_rt_handler(struct ctl_table *table, int write, 7675 void __user *buffer, size_t *lenp, 7676 loff_t *ppos) 7677{ 7678 int old_period, old_runtime; 7679 static DEFINE_MUTEX(mutex); 7680 int ret; 7681 7682 mutex_lock(&mutex); 7683 old_period = sysctl_sched_rt_period; 7684 old_runtime = sysctl_sched_rt_runtime; 7685 7686 ret = proc_dointvec(table, write, buffer, lenp, ppos); 7687 7688 if (!ret && write) { 7689 ret = sched_rt_global_validate(); 7690 if (ret) 7691 goto undo; 7692 7693 ret = sched_rt_global_constraints(); 7694 if (ret) 7695 goto undo; 7696 7697 ret = sched_dl_global_constraints(); 7698 if (ret) 7699 goto undo; 7700 7701 sched_rt_do_global(); 7702 sched_dl_do_global(); 7703 } 7704 if (0) { 7705undo: 7706 sysctl_sched_rt_period = old_period; 7707 sysctl_sched_rt_runtime = old_runtime; 7708 } 7709 mutex_unlock(&mutex); 7710 7711 return ret; 7712} 7713 7714int sched_rr_handler(struct ctl_table *table, int write, 7715 void __user *buffer, size_t *lenp, 7716 loff_t *ppos) 7717{ 7718 int ret; 7719 static DEFINE_MUTEX(mutex); 7720 7721 mutex_lock(&mutex); 7722 ret = proc_dointvec(table, write, buffer, lenp, ppos); 7723 /* make sure that internally we keep jiffies */ 7724 /* also, writing zero resets timeslice to default */ 7725 if (!ret && write) { 7726 sched_rr_timeslice = sched_rr_timeslice <= 0 ? 7727 RR_TIMESLICE : msecs_to_jiffies(sched_rr_timeslice); 7728 } 7729 mutex_unlock(&mutex); 7730 return ret; 7731} 7732 7733#ifdef CONFIG_CGROUP_SCHED 7734 7735static inline struct task_group *css_tg(struct cgroup_subsys_state *css) 7736{ 7737 return css ? container_of(css, struct task_group, css) : NULL; 7738} 7739 7740static struct cgroup_subsys_state * 7741cpu_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) 7742{ 7743 struct task_group *parent = css_tg(parent_css); 7744 struct task_group *tg; 7745 7746 if (!parent) { 7747 /* This is early initialization for the top cgroup */ 7748 return &root_task_group.css; 7749 } 7750 7751 tg = sched_create_group(parent); 7752 if (IS_ERR(tg)) 7753 return ERR_PTR(-ENOMEM); 7754 7755 return &tg->css; 7756} 7757 7758static int cpu_cgroup_css_online(struct cgroup_subsys_state *css) 7759{ 7760 struct task_group *tg = css_tg(css); 7761 struct task_group *parent = css_tg(css->parent); 7762 7763 if (parent) 7764 sched_online_group(tg, parent); 7765 return 0; 7766} 7767 7768static void cpu_cgroup_css_free(struct cgroup_subsys_state *css) 7769{ 7770 struct task_group *tg = css_tg(css); 7771 7772 sched_destroy_group(tg); 7773} 7774 7775static void cpu_cgroup_css_offline(struct cgroup_subsys_state *css) 7776{ 7777 struct task_group *tg = css_tg(css); 7778 7779 sched_offline_group(tg); 7780} 7781 7782static int cpu_cgroup_can_attach(struct cgroup_subsys_state *css, 7783 struct cgroup_taskset *tset) 7784{ 7785 struct task_struct *task; 7786 7787 cgroup_taskset_for_each(task, tset) { 7788#ifdef CONFIG_RT_GROUP_SCHED 7789 if (!sched_rt_can_attach(css_tg(css), task)) 7790 return -EINVAL; 7791#else 7792 /* We don't support RT-tasks being in separate groups */ 7793 if (task->sched_class != &fair_sched_class) 7794 return -EINVAL; 7795#endif 7796 } 7797 return 0; 7798} 7799 7800static void cpu_cgroup_attach(struct cgroup_subsys_state *css, 7801 struct cgroup_taskset *tset) 7802{ 7803 struct task_struct *task; 7804 7805 cgroup_taskset_for_each(task, tset) 7806 sched_move_task(task); 7807} 7808 7809static void cpu_cgroup_exit(struct cgroup_subsys_state *css, 7810 struct cgroup_subsys_state *old_css, 7811 struct task_struct *task) 7812{ 7813 /* 7814 * cgroup_exit() is called in the copy_process() failure path. 7815 * Ignore this case since the task hasn't ran yet, this avoids 7816 * trying to poke a half freed task state from generic code. 7817 */ 7818 if (!(task->flags & PF_EXITING)) 7819 return; 7820 7821 sched_move_task(task); 7822} 7823 7824#ifdef CONFIG_FAIR_GROUP_SCHED 7825static int cpu_shares_write_u64(struct cgroup_subsys_state *css, 7826 struct cftype *cftype, u64 shareval) 7827{ 7828 return sched_group_set_shares(css_tg(css), scale_load(shareval)); 7829} 7830 7831static u64 cpu_shares_read_u64(struct cgroup_subsys_state *css, 7832 struct cftype *cft) 7833{ 7834 struct task_group *tg = css_tg(css); 7835 7836 return (u64) scale_load_down(tg->shares); 7837} 7838 7839#ifdef CONFIG_CFS_BANDWIDTH 7840static DEFINE_MUTEX(cfs_constraints_mutex); 7841 7842const u64 max_cfs_quota_period = 1 * NSEC_PER_SEC; /* 1s */ 7843const u64 min_cfs_quota_period = 1 * NSEC_PER_MSEC; /* 1ms */ 7844 7845static int __cfs_schedulable(struct task_group *tg, u64 period, u64 runtime); 7846 7847static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota) 7848{ 7849 int i, ret = 0, runtime_enabled, runtime_was_enabled; 7850 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 7851 7852 if (tg == &root_task_group) 7853 return -EINVAL; 7854 7855 /* 7856 * Ensure we have at some amount of bandwidth every period. This is 7857 * to prevent reaching a state of large arrears when throttled via 7858 * entity_tick() resulting in prolonged exit starvation. 7859 */ 7860 if (quota < min_cfs_quota_period || period < min_cfs_quota_period) 7861 return -EINVAL; 7862 7863 /* 7864 * Likewise, bound things on the otherside by preventing insane quota 7865 * periods. This also allows us to normalize in computing quota 7866 * feasibility. 7867 */ 7868 if (period > max_cfs_quota_period) 7869 return -EINVAL; 7870 7871 /* 7872 * Prevent race between setting of cfs_rq->runtime_enabled and 7873 * unthrottle_offline_cfs_rqs(). 7874 */ 7875 get_online_cpus(); 7876 mutex_lock(&cfs_constraints_mutex); 7877 ret = __cfs_schedulable(tg, period, quota); 7878 if (ret) 7879 goto out_unlock; 7880 7881 runtime_enabled = quota != RUNTIME_INF; 7882 runtime_was_enabled = cfs_b->quota != RUNTIME_INF; 7883 /* 7884 * If we need to toggle cfs_bandwidth_used, off->on must occur 7885 * before making related changes, and on->off must occur afterwards 7886 */ 7887 if (runtime_enabled && !runtime_was_enabled) 7888 cfs_bandwidth_usage_inc(); 7889 raw_spin_lock_irq(&cfs_b->lock); 7890 cfs_b->period = ns_to_ktime(period); 7891 cfs_b->quota = quota; 7892 7893 __refill_cfs_bandwidth_runtime(cfs_b); 7894 /* restart the period timer (if active) to handle new period expiry */ 7895 if (runtime_enabled && cfs_b->timer_active) { 7896 /* force a reprogram */ 7897 __start_cfs_bandwidth(cfs_b, true); 7898 } 7899 raw_spin_unlock_irq(&cfs_b->lock); 7900 7901 for_each_online_cpu(i) { 7902 struct cfs_rq *cfs_rq = tg->cfs_rq[i]; 7903 struct rq *rq = cfs_rq->rq; 7904 7905 raw_spin_lock_irq(&rq->lock); 7906 cfs_rq->runtime_enabled = runtime_enabled; 7907 cfs_rq->runtime_remaining = 0; 7908 7909 if (cfs_rq->throttled) 7910 unthrottle_cfs_rq(cfs_rq); 7911 raw_spin_unlock_irq(&rq->lock); 7912 } 7913 if (runtime_was_enabled && !runtime_enabled) 7914 cfs_bandwidth_usage_dec(); 7915out_unlock: 7916 mutex_unlock(&cfs_constraints_mutex); 7917 put_online_cpus(); 7918 7919 return ret; 7920} 7921 7922int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us) 7923{ 7924 u64 quota, period; 7925 7926 period = ktime_to_ns(tg->cfs_bandwidth.period); 7927 if (cfs_quota_us < 0) 7928 quota = RUNTIME_INF; 7929 else 7930 quota = (u64)cfs_quota_us * NSEC_PER_USEC; 7931 7932 return tg_set_cfs_bandwidth(tg, period, quota); 7933} 7934 7935long tg_get_cfs_quota(struct task_group *tg) 7936{ 7937 u64 quota_us; 7938 7939 if (tg->cfs_bandwidth.quota == RUNTIME_INF) 7940 return -1; 7941 7942 quota_us = tg->cfs_bandwidth.quota; 7943 do_div(quota_us, NSEC_PER_USEC); 7944 7945 return quota_us; 7946} 7947 7948int tg_set_cfs_period(struct task_group *tg, long cfs_period_us) 7949{ 7950 u64 quota, period; 7951 7952 period = (u64)cfs_period_us * NSEC_PER_USEC; 7953 quota = tg->cfs_bandwidth.quota; 7954 7955 return tg_set_cfs_bandwidth(tg, period, quota); 7956} 7957 7958long tg_get_cfs_period(struct task_group *tg) 7959{ 7960 u64 cfs_period_us; 7961 7962 cfs_period_us = ktime_to_ns(tg->cfs_bandwidth.period); 7963 do_div(cfs_period_us, NSEC_PER_USEC); 7964 7965 return cfs_period_us; 7966} 7967 7968static s64 cpu_cfs_quota_read_s64(struct cgroup_subsys_state *css, 7969 struct cftype *cft) 7970{ 7971 return tg_get_cfs_quota(css_tg(css)); 7972} 7973 7974static int cpu_cfs_quota_write_s64(struct cgroup_subsys_state *css, 7975 struct cftype *cftype, s64 cfs_quota_us) 7976{ 7977 return tg_set_cfs_quota(css_tg(css), cfs_quota_us); 7978} 7979 7980static u64 cpu_cfs_period_read_u64(struct cgroup_subsys_state *css, 7981 struct cftype *cft) 7982{ 7983 return tg_get_cfs_period(css_tg(css)); 7984} 7985 7986static int cpu_cfs_period_write_u64(struct cgroup_subsys_state *css, 7987 struct cftype *cftype, u64 cfs_period_us) 7988{ 7989 return tg_set_cfs_period(css_tg(css), cfs_period_us); 7990} 7991 7992struct cfs_schedulable_data { 7993 struct task_group *tg; 7994 u64 period, quota; 7995}; 7996 7997/* 7998 * normalize group quota/period to be quota/max_period 7999 * note: units are usecs 8000 */ 8001static u64 normalize_cfs_quota(struct task_group *tg, 8002 struct cfs_schedulable_data *d) 8003{ 8004 u64 quota, period; 8005 8006 if (tg == d->tg) { 8007 period = d->period; 8008 quota = d->quota; 8009 } else { 8010 period = tg_get_cfs_period(tg); 8011 quota = tg_get_cfs_quota(tg); 8012 } 8013 8014 /* note: these should typically be equivalent */ 8015 if (quota == RUNTIME_INF || quota == -1) 8016 return RUNTIME_INF; 8017 8018 return to_ratio(period, quota); 8019} 8020 8021static int tg_cfs_schedulable_down(struct task_group *tg, void *data) 8022{ 8023 struct cfs_schedulable_data *d = data; 8024 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 8025 s64 quota = 0, parent_quota = -1; 8026 8027 if (!tg->parent) { 8028 quota = RUNTIME_INF; 8029 } else { 8030 struct cfs_bandwidth *parent_b = &tg->parent->cfs_bandwidth; 8031 8032 quota = normalize_cfs_quota(tg, d); 8033 parent_quota = parent_b->hierarchal_quota; 8034 8035 /* 8036 * ensure max(child_quota) <= parent_quota, inherit when no 8037 * limit is set 8038 */ 8039 if (quota == RUNTIME_INF) 8040 quota = parent_quota; 8041 else if (parent_quota != RUNTIME_INF && quota > parent_quota) 8042 return -EINVAL; 8043 } 8044 cfs_b->hierarchal_quota = quota; 8045 8046 return 0; 8047} 8048 8049static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota) 8050{ 8051 int ret; 8052 struct cfs_schedulable_data data = { 8053 .tg = tg, 8054 .period = period, 8055 .quota = quota, 8056 }; 8057 8058 if (quota != RUNTIME_INF) { 8059 do_div(data.period, NSEC_PER_USEC); 8060 do_div(data.quota, NSEC_PER_USEC); 8061 } 8062 8063 rcu_read_lock(); 8064 ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data); 8065 rcu_read_unlock(); 8066 8067 return ret; 8068} 8069 8070static int cpu_stats_show(struct seq_file *sf, void *v) 8071{ 8072 struct task_group *tg = css_tg(seq_css(sf)); 8073 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 8074 8075 seq_printf(sf, "nr_periods %d\n", cfs_b->nr_periods); 8076 seq_printf(sf, "nr_throttled %d\n", cfs_b->nr_throttled); 8077 seq_printf(sf, "throttled_time %llu\n", cfs_b->throttled_time); 8078 8079 return 0; 8080} 8081#endif /* CONFIG_CFS_BANDWIDTH */ 8082#endif /* CONFIG_FAIR_GROUP_SCHED */ 8083 8084#ifdef CONFIG_RT_GROUP_SCHED 8085static int cpu_rt_runtime_write(struct cgroup_subsys_state *css, 8086 struct cftype *cft, s64 val) 8087{ 8088 return sched_group_set_rt_runtime(css_tg(css), val); 8089} 8090 8091static s64 cpu_rt_runtime_read(struct cgroup_subsys_state *css, 8092 struct cftype *cft) 8093{ 8094 return sched_group_rt_runtime(css_tg(css)); 8095} 8096 8097static int cpu_rt_period_write_uint(struct cgroup_subsys_state *css, 8098 struct cftype *cftype, u64 rt_period_us) 8099{ 8100 return sched_group_set_rt_period(css_tg(css), rt_period_us); 8101} 8102 8103static u64 cpu_rt_period_read_uint(struct cgroup_subsys_state *css, 8104 struct cftype *cft) 8105{ 8106 return sched_group_rt_period(css_tg(css)); 8107} 8108#endif /* CONFIG_RT_GROUP_SCHED */ 8109 8110static struct cftype cpu_files[] = { 8111#ifdef CONFIG_FAIR_GROUP_SCHED 8112 { 8113 .name = "shares", 8114 .read_u64 = cpu_shares_read_u64, 8115 .write_u64 = cpu_shares_write_u64, 8116 }, 8117#endif 8118#ifdef CONFIG_CFS_BANDWIDTH 8119 { 8120 .name = "cfs_quota_us", 8121 .read_s64 = cpu_cfs_quota_read_s64, 8122 .write_s64 = cpu_cfs_quota_write_s64, 8123 }, 8124 { 8125 .name = "cfs_period_us", 8126 .read_u64 = cpu_cfs_period_read_u64, 8127 .write_u64 = cpu_cfs_period_write_u64, 8128 }, 8129 { 8130 .name = "stat", 8131 .seq_show = cpu_stats_show, 8132 }, 8133#endif 8134#ifdef CONFIG_RT_GROUP_SCHED 8135 { 8136 .name = "rt_runtime_us", 8137 .read_s64 = cpu_rt_runtime_read, 8138 .write_s64 = cpu_rt_runtime_write, 8139 }, 8140 { 8141 .name = "rt_period_us", 8142 .read_u64 = cpu_rt_period_read_uint, 8143 .write_u64 = cpu_rt_period_write_uint, 8144 }, 8145#endif 8146 { } /* terminate */ 8147}; 8148 8149struct cgroup_subsys cpu_cgrp_subsys = { 8150 .css_alloc = cpu_cgroup_css_alloc, 8151 .css_free = cpu_cgroup_css_free, 8152 .css_online = cpu_cgroup_css_online, 8153 .css_offline = cpu_cgroup_css_offline, 8154 .can_attach = cpu_cgroup_can_attach, 8155 .attach = cpu_cgroup_attach, 8156 .exit = cpu_cgroup_exit, 8157 .legacy_cftypes = cpu_files, 8158 .early_init = 1, 8159}; 8160 8161#endif /* CONFIG_CGROUP_SCHED */ 8162 8163void dump_cpu_task(int cpu) 8164{ 8165 pr_info("Task dump for CPU %d:\n", cpu); 8166 sched_show_task(cpu_curr(cpu)); 8167} 8168