core.c revision a15b12ac36ad4e7b856a4ae54937ae26a51aebad
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 1637void wake_up_if_idle(int cpu) 1638{ 1639 struct rq *rq = cpu_rq(cpu); 1640 unsigned long flags; 1641 1642 if (!is_idle_task(rq->curr)) 1643 return; 1644 1645 if (set_nr_if_polling(rq->idle)) { 1646 trace_sched_wake_idle_without_ipi(cpu); 1647 } else { 1648 raw_spin_lock_irqsave(&rq->lock, flags); 1649 if (is_idle_task(rq->curr)) 1650 smp_send_reschedule(cpu); 1651 /* Else cpu is not in idle, do nothing here */ 1652 raw_spin_unlock_irqrestore(&rq->lock, flags); 1653 } 1654} 1655 1656bool cpus_share_cache(int this_cpu, int that_cpu) 1657{ 1658 return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu); 1659} 1660#endif /* CONFIG_SMP */ 1661 1662static void ttwu_queue(struct task_struct *p, int cpu) 1663{ 1664 struct rq *rq = cpu_rq(cpu); 1665 1666#if defined(CONFIG_SMP) 1667 if (sched_feat(TTWU_QUEUE) && !cpus_share_cache(smp_processor_id(), cpu)) { 1668 sched_clock_cpu(cpu); /* sync clocks x-cpu */ 1669 ttwu_queue_remote(p, cpu); 1670 return; 1671 } 1672#endif 1673 1674 raw_spin_lock(&rq->lock); 1675 ttwu_do_activate(rq, p, 0); 1676 raw_spin_unlock(&rq->lock); 1677} 1678 1679/** 1680 * try_to_wake_up - wake up a thread 1681 * @p: the thread to be awakened 1682 * @state: the mask of task states that can be woken 1683 * @wake_flags: wake modifier flags (WF_*) 1684 * 1685 * Put it on the run-queue if it's not already there. The "current" 1686 * thread is always on the run-queue (except when the actual 1687 * re-schedule is in progress), and as such you're allowed to do 1688 * the simpler "current->state = TASK_RUNNING" to mark yourself 1689 * runnable without the overhead of this. 1690 * 1691 * Return: %true if @p was woken up, %false if it was already running. 1692 * or @state didn't match @p's state. 1693 */ 1694static int 1695try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) 1696{ 1697 unsigned long flags; 1698 int cpu, success = 0; 1699 1700 /* 1701 * If we are going to wake up a thread waiting for CONDITION we 1702 * need to ensure that CONDITION=1 done by the caller can not be 1703 * reordered with p->state check below. This pairs with mb() in 1704 * set_current_state() the waiting thread does. 1705 */ 1706 smp_mb__before_spinlock(); 1707 raw_spin_lock_irqsave(&p->pi_lock, flags); 1708 if (!(p->state & state)) 1709 goto out; 1710 1711 success = 1; /* we're going to change ->state */ 1712 cpu = task_cpu(p); 1713 1714 if (p->on_rq && ttwu_remote(p, wake_flags)) 1715 goto stat; 1716 1717#ifdef CONFIG_SMP 1718 /* 1719 * If the owning (remote) cpu is still in the middle of schedule() with 1720 * this task as prev, wait until its done referencing the task. 1721 */ 1722 while (p->on_cpu) 1723 cpu_relax(); 1724 /* 1725 * Pairs with the smp_wmb() in finish_lock_switch(). 1726 */ 1727 smp_rmb(); 1728 1729 p->sched_contributes_to_load = !!task_contributes_to_load(p); 1730 p->state = TASK_WAKING; 1731 1732 if (p->sched_class->task_waking) 1733 p->sched_class->task_waking(p); 1734 1735 cpu = select_task_rq(p, p->wake_cpu, SD_BALANCE_WAKE, wake_flags); 1736 if (task_cpu(p) != cpu) { 1737 wake_flags |= WF_MIGRATED; 1738 set_task_cpu(p, cpu); 1739 } 1740#endif /* CONFIG_SMP */ 1741 1742 ttwu_queue(p, cpu); 1743stat: 1744 ttwu_stat(p, cpu, wake_flags); 1745out: 1746 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 1747 1748 return success; 1749} 1750 1751/** 1752 * try_to_wake_up_local - try to wake up a local task with rq lock held 1753 * @p: the thread to be awakened 1754 * 1755 * Put @p on the run-queue if it's not already there. The caller must 1756 * ensure that this_rq() is locked, @p is bound to this_rq() and not 1757 * the current task. 1758 */ 1759static void try_to_wake_up_local(struct task_struct *p) 1760{ 1761 struct rq *rq = task_rq(p); 1762 1763 if (WARN_ON_ONCE(rq != this_rq()) || 1764 WARN_ON_ONCE(p == current)) 1765 return; 1766 1767 lockdep_assert_held(&rq->lock); 1768 1769 if (!raw_spin_trylock(&p->pi_lock)) { 1770 raw_spin_unlock(&rq->lock); 1771 raw_spin_lock(&p->pi_lock); 1772 raw_spin_lock(&rq->lock); 1773 } 1774 1775 if (!(p->state & TASK_NORMAL)) 1776 goto out; 1777 1778 if (!task_on_rq_queued(p)) 1779 ttwu_activate(rq, p, ENQUEUE_WAKEUP); 1780 1781 ttwu_do_wakeup(rq, p, 0); 1782 ttwu_stat(p, smp_processor_id(), 0); 1783out: 1784 raw_spin_unlock(&p->pi_lock); 1785} 1786 1787/** 1788 * wake_up_process - Wake up a specific process 1789 * @p: The process to be woken up. 1790 * 1791 * Attempt to wake up the nominated process and move it to the set of runnable 1792 * processes. 1793 * 1794 * Return: 1 if the process was woken up, 0 if it was already running. 1795 * 1796 * It may be assumed that this function implies a write memory barrier before 1797 * changing the task state if and only if any tasks are woken up. 1798 */ 1799int wake_up_process(struct task_struct *p) 1800{ 1801 WARN_ON(task_is_stopped_or_traced(p)); 1802 return try_to_wake_up(p, TASK_NORMAL, 0); 1803} 1804EXPORT_SYMBOL(wake_up_process); 1805 1806int wake_up_state(struct task_struct *p, unsigned int state) 1807{ 1808 return try_to_wake_up(p, state, 0); 1809} 1810 1811/* 1812 * Perform scheduler related setup for a newly forked process p. 1813 * p is forked by current. 1814 * 1815 * __sched_fork() is basic setup used by init_idle() too: 1816 */ 1817static void __sched_fork(unsigned long clone_flags, struct task_struct *p) 1818{ 1819 p->on_rq = 0; 1820 1821 p->se.on_rq = 0; 1822 p->se.exec_start = 0; 1823 p->se.sum_exec_runtime = 0; 1824 p->se.prev_sum_exec_runtime = 0; 1825 p->se.nr_migrations = 0; 1826 p->se.vruntime = 0; 1827 INIT_LIST_HEAD(&p->se.group_node); 1828 1829#ifdef CONFIG_SCHEDSTATS 1830 memset(&p->se.statistics, 0, sizeof(p->se.statistics)); 1831#endif 1832 1833 RB_CLEAR_NODE(&p->dl.rb_node); 1834 hrtimer_init(&p->dl.dl_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 1835 p->dl.dl_runtime = p->dl.runtime = 0; 1836 p->dl.dl_deadline = p->dl.deadline = 0; 1837 p->dl.dl_period = 0; 1838 p->dl.flags = 0; 1839 1840 INIT_LIST_HEAD(&p->rt.run_list); 1841 1842#ifdef CONFIG_PREEMPT_NOTIFIERS 1843 INIT_HLIST_HEAD(&p->preempt_notifiers); 1844#endif 1845 1846#ifdef CONFIG_NUMA_BALANCING 1847 if (p->mm && atomic_read(&p->mm->mm_users) == 1) { 1848 p->mm->numa_next_scan = jiffies + msecs_to_jiffies(sysctl_numa_balancing_scan_delay); 1849 p->mm->numa_scan_seq = 0; 1850 } 1851 1852 if (clone_flags & CLONE_VM) 1853 p->numa_preferred_nid = current->numa_preferred_nid; 1854 else 1855 p->numa_preferred_nid = -1; 1856 1857 p->node_stamp = 0ULL; 1858 p->numa_scan_seq = p->mm ? p->mm->numa_scan_seq : 0; 1859 p->numa_scan_period = sysctl_numa_balancing_scan_delay; 1860 p->numa_work.next = &p->numa_work; 1861 p->numa_faults_memory = NULL; 1862 p->numa_faults_buffer_memory = NULL; 1863 p->last_task_numa_placement = 0; 1864 p->last_sum_exec_runtime = 0; 1865 1866 INIT_LIST_HEAD(&p->numa_entry); 1867 p->numa_group = NULL; 1868#endif /* CONFIG_NUMA_BALANCING */ 1869} 1870 1871#ifdef CONFIG_NUMA_BALANCING 1872#ifdef CONFIG_SCHED_DEBUG 1873void set_numabalancing_state(bool enabled) 1874{ 1875 if (enabled) 1876 sched_feat_set("NUMA"); 1877 else 1878 sched_feat_set("NO_NUMA"); 1879} 1880#else 1881__read_mostly bool numabalancing_enabled; 1882 1883void set_numabalancing_state(bool enabled) 1884{ 1885 numabalancing_enabled = enabled; 1886} 1887#endif /* CONFIG_SCHED_DEBUG */ 1888 1889#ifdef CONFIG_PROC_SYSCTL 1890int sysctl_numa_balancing(struct ctl_table *table, int write, 1891 void __user *buffer, size_t *lenp, loff_t *ppos) 1892{ 1893 struct ctl_table t; 1894 int err; 1895 int state = numabalancing_enabled; 1896 1897 if (write && !capable(CAP_SYS_ADMIN)) 1898 return -EPERM; 1899 1900 t = *table; 1901 t.data = &state; 1902 err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos); 1903 if (err < 0) 1904 return err; 1905 if (write) 1906 set_numabalancing_state(state); 1907 return err; 1908} 1909#endif 1910#endif 1911 1912/* 1913 * fork()/clone()-time setup: 1914 */ 1915int sched_fork(unsigned long clone_flags, struct task_struct *p) 1916{ 1917 unsigned long flags; 1918 int cpu = get_cpu(); 1919 1920 __sched_fork(clone_flags, p); 1921 /* 1922 * We mark the process as running here. This guarantees that 1923 * nobody will actually run it, and a signal or other external 1924 * event cannot wake it up and insert it on the runqueue either. 1925 */ 1926 p->state = TASK_RUNNING; 1927 1928 /* 1929 * Make sure we do not leak PI boosting priority to the child. 1930 */ 1931 p->prio = current->normal_prio; 1932 1933 /* 1934 * Revert to default priority/policy on fork if requested. 1935 */ 1936 if (unlikely(p->sched_reset_on_fork)) { 1937 if (task_has_dl_policy(p) || task_has_rt_policy(p)) { 1938 p->policy = SCHED_NORMAL; 1939 p->static_prio = NICE_TO_PRIO(0); 1940 p->rt_priority = 0; 1941 } else if (PRIO_TO_NICE(p->static_prio) < 0) 1942 p->static_prio = NICE_TO_PRIO(0); 1943 1944 p->prio = p->normal_prio = __normal_prio(p); 1945 set_load_weight(p); 1946 1947 /* 1948 * We don't need the reset flag anymore after the fork. It has 1949 * fulfilled its duty: 1950 */ 1951 p->sched_reset_on_fork = 0; 1952 } 1953 1954 if (dl_prio(p->prio)) { 1955 put_cpu(); 1956 return -EAGAIN; 1957 } else if (rt_prio(p->prio)) { 1958 p->sched_class = &rt_sched_class; 1959 } else { 1960 p->sched_class = &fair_sched_class; 1961 } 1962 1963 if (p->sched_class->task_fork) 1964 p->sched_class->task_fork(p); 1965 1966 /* 1967 * The child is not yet in the pid-hash so no cgroup attach races, 1968 * and the cgroup is pinned to this child due to cgroup_fork() 1969 * is ran before sched_fork(). 1970 * 1971 * Silence PROVE_RCU. 1972 */ 1973 raw_spin_lock_irqsave(&p->pi_lock, flags); 1974 set_task_cpu(p, cpu); 1975 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 1976 1977#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) 1978 if (likely(sched_info_on())) 1979 memset(&p->sched_info, 0, sizeof(p->sched_info)); 1980#endif 1981#if defined(CONFIG_SMP) 1982 p->on_cpu = 0; 1983#endif 1984 init_task_preempt_count(p); 1985#ifdef CONFIG_SMP 1986 plist_node_init(&p->pushable_tasks, MAX_PRIO); 1987 RB_CLEAR_NODE(&p->pushable_dl_tasks); 1988#endif 1989 1990 put_cpu(); 1991 return 0; 1992} 1993 1994unsigned long to_ratio(u64 period, u64 runtime) 1995{ 1996 if (runtime == RUNTIME_INF) 1997 return 1ULL << 20; 1998 1999 /* 2000 * Doing this here saves a lot of checks in all 2001 * the calling paths, and returning zero seems 2002 * safe for them anyway. 2003 */ 2004 if (period == 0) 2005 return 0; 2006 2007 return div64_u64(runtime << 20, period); 2008} 2009 2010#ifdef CONFIG_SMP 2011inline struct dl_bw *dl_bw_of(int i) 2012{ 2013 return &cpu_rq(i)->rd->dl_bw; 2014} 2015 2016static inline int dl_bw_cpus(int i) 2017{ 2018 struct root_domain *rd = cpu_rq(i)->rd; 2019 int cpus = 0; 2020 2021 for_each_cpu_and(i, rd->span, cpu_active_mask) 2022 cpus++; 2023 2024 return cpus; 2025} 2026#else 2027inline struct dl_bw *dl_bw_of(int i) 2028{ 2029 return &cpu_rq(i)->dl.dl_bw; 2030} 2031 2032static inline int dl_bw_cpus(int i) 2033{ 2034 return 1; 2035} 2036#endif 2037 2038static inline 2039void __dl_clear(struct dl_bw *dl_b, u64 tsk_bw) 2040{ 2041 dl_b->total_bw -= tsk_bw; 2042} 2043 2044static inline 2045void __dl_add(struct dl_bw *dl_b, u64 tsk_bw) 2046{ 2047 dl_b->total_bw += tsk_bw; 2048} 2049 2050static inline 2051bool __dl_overflow(struct dl_bw *dl_b, int cpus, u64 old_bw, u64 new_bw) 2052{ 2053 return dl_b->bw != -1 && 2054 dl_b->bw * cpus < dl_b->total_bw - old_bw + new_bw; 2055} 2056 2057/* 2058 * We must be sure that accepting a new task (or allowing changing the 2059 * parameters of an existing one) is consistent with the bandwidth 2060 * constraints. If yes, this function also accordingly updates the currently 2061 * allocated bandwidth to reflect the new situation. 2062 * 2063 * This function is called while holding p's rq->lock. 2064 */ 2065static int dl_overflow(struct task_struct *p, int policy, 2066 const struct sched_attr *attr) 2067{ 2068 2069 struct dl_bw *dl_b = dl_bw_of(task_cpu(p)); 2070 u64 period = attr->sched_period ?: attr->sched_deadline; 2071 u64 runtime = attr->sched_runtime; 2072 u64 new_bw = dl_policy(policy) ? to_ratio(period, runtime) : 0; 2073 int cpus, err = -1; 2074 2075 if (new_bw == p->dl.dl_bw) 2076 return 0; 2077 2078 /* 2079 * Either if a task, enters, leave, or stays -deadline but changes 2080 * its parameters, we may need to update accordingly the total 2081 * allocated bandwidth of the container. 2082 */ 2083 raw_spin_lock(&dl_b->lock); 2084 cpus = dl_bw_cpus(task_cpu(p)); 2085 if (dl_policy(policy) && !task_has_dl_policy(p) && 2086 !__dl_overflow(dl_b, cpus, 0, new_bw)) { 2087 __dl_add(dl_b, new_bw); 2088 err = 0; 2089 } else if (dl_policy(policy) && task_has_dl_policy(p) && 2090 !__dl_overflow(dl_b, cpus, p->dl.dl_bw, new_bw)) { 2091 __dl_clear(dl_b, p->dl.dl_bw); 2092 __dl_add(dl_b, new_bw); 2093 err = 0; 2094 } else if (!dl_policy(policy) && task_has_dl_policy(p)) { 2095 __dl_clear(dl_b, p->dl.dl_bw); 2096 err = 0; 2097 } 2098 raw_spin_unlock(&dl_b->lock); 2099 2100 return err; 2101} 2102 2103extern void init_dl_bw(struct dl_bw *dl_b); 2104 2105/* 2106 * wake_up_new_task - wake up a newly created task for the first time. 2107 * 2108 * This function will do some initial scheduler statistics housekeeping 2109 * that must be done for every newly created context, then puts the task 2110 * on the runqueue and wakes it. 2111 */ 2112void wake_up_new_task(struct task_struct *p) 2113{ 2114 unsigned long flags; 2115 struct rq *rq; 2116 2117 raw_spin_lock_irqsave(&p->pi_lock, flags); 2118#ifdef CONFIG_SMP 2119 /* 2120 * Fork balancing, do it here and not earlier because: 2121 * - cpus_allowed can change in the fork path 2122 * - any previously selected cpu might disappear through hotplug 2123 */ 2124 set_task_cpu(p, select_task_rq(p, task_cpu(p), SD_BALANCE_FORK, 0)); 2125#endif 2126 2127 /* Initialize new task's runnable average */ 2128 init_task_runnable_average(p); 2129 rq = __task_rq_lock(p); 2130 activate_task(rq, p, 0); 2131 p->on_rq = TASK_ON_RQ_QUEUED; 2132 trace_sched_wakeup_new(p, true); 2133 check_preempt_curr(rq, p, WF_FORK); 2134#ifdef CONFIG_SMP 2135 if (p->sched_class->task_woken) 2136 p->sched_class->task_woken(rq, p); 2137#endif 2138 task_rq_unlock(rq, p, &flags); 2139} 2140 2141#ifdef CONFIG_PREEMPT_NOTIFIERS 2142 2143/** 2144 * preempt_notifier_register - tell me when current is being preempted & rescheduled 2145 * @notifier: notifier struct to register 2146 */ 2147void preempt_notifier_register(struct preempt_notifier *notifier) 2148{ 2149 hlist_add_head(¬ifier->link, ¤t->preempt_notifiers); 2150} 2151EXPORT_SYMBOL_GPL(preempt_notifier_register); 2152 2153/** 2154 * preempt_notifier_unregister - no longer interested in preemption notifications 2155 * @notifier: notifier struct to unregister 2156 * 2157 * This is safe to call from within a preemption notifier. 2158 */ 2159void preempt_notifier_unregister(struct preempt_notifier *notifier) 2160{ 2161 hlist_del(¬ifier->link); 2162} 2163EXPORT_SYMBOL_GPL(preempt_notifier_unregister); 2164 2165static void fire_sched_in_preempt_notifiers(struct task_struct *curr) 2166{ 2167 struct preempt_notifier *notifier; 2168 2169 hlist_for_each_entry(notifier, &curr->preempt_notifiers, link) 2170 notifier->ops->sched_in(notifier, raw_smp_processor_id()); 2171} 2172 2173static void 2174fire_sched_out_preempt_notifiers(struct task_struct *curr, 2175 struct task_struct *next) 2176{ 2177 struct preempt_notifier *notifier; 2178 2179 hlist_for_each_entry(notifier, &curr->preempt_notifiers, link) 2180 notifier->ops->sched_out(notifier, next); 2181} 2182 2183#else /* !CONFIG_PREEMPT_NOTIFIERS */ 2184 2185static void fire_sched_in_preempt_notifiers(struct task_struct *curr) 2186{ 2187} 2188 2189static void 2190fire_sched_out_preempt_notifiers(struct task_struct *curr, 2191 struct task_struct *next) 2192{ 2193} 2194 2195#endif /* CONFIG_PREEMPT_NOTIFIERS */ 2196 2197/** 2198 * prepare_task_switch - prepare to switch tasks 2199 * @rq: the runqueue preparing to switch 2200 * @prev: the current task that is being switched out 2201 * @next: the task we are going to switch to. 2202 * 2203 * This is called with the rq lock held and interrupts off. It must 2204 * be paired with a subsequent finish_task_switch after the context 2205 * switch. 2206 * 2207 * prepare_task_switch sets up locking and calls architecture specific 2208 * hooks. 2209 */ 2210static inline void 2211prepare_task_switch(struct rq *rq, struct task_struct *prev, 2212 struct task_struct *next) 2213{ 2214 trace_sched_switch(prev, next); 2215 sched_info_switch(rq, prev, next); 2216 perf_event_task_sched_out(prev, next); 2217 fire_sched_out_preempt_notifiers(prev, next); 2218 prepare_lock_switch(rq, next); 2219 prepare_arch_switch(next); 2220} 2221 2222/** 2223 * finish_task_switch - clean up after a task-switch 2224 * @rq: runqueue associated with task-switch 2225 * @prev: the thread we just switched away from. 2226 * 2227 * finish_task_switch must be called after the context switch, paired 2228 * with a prepare_task_switch call before the context switch. 2229 * finish_task_switch will reconcile locking set up by prepare_task_switch, 2230 * and do any other architecture-specific cleanup actions. 2231 * 2232 * Note that we may have delayed dropping an mm in context_switch(). If 2233 * so, we finish that here outside of the runqueue lock. (Doing it 2234 * with the lock held can cause deadlocks; see schedule() for 2235 * details.) 2236 */ 2237static void finish_task_switch(struct rq *rq, struct task_struct *prev) 2238 __releases(rq->lock) 2239{ 2240 struct mm_struct *mm = rq->prev_mm; 2241 long prev_state; 2242 2243 rq->prev_mm = NULL; 2244 2245 /* 2246 * A task struct has one reference for the use as "current". 2247 * If a task dies, then it sets TASK_DEAD in tsk->state and calls 2248 * schedule one last time. The schedule call will never return, and 2249 * the scheduled task must drop that reference. 2250 * The test for TASK_DEAD must occur while the runqueue locks are 2251 * still held, otherwise prev could be scheduled on another cpu, die 2252 * there before we look at prev->state, and then the reference would 2253 * be dropped twice. 2254 * Manfred Spraul <manfred@colorfullife.com> 2255 */ 2256 prev_state = prev->state; 2257 vtime_task_switch(prev); 2258 finish_arch_switch(prev); 2259 perf_event_task_sched_in(prev, current); 2260 finish_lock_switch(rq, prev); 2261 finish_arch_post_lock_switch(); 2262 2263 fire_sched_in_preempt_notifiers(current); 2264 if (mm) 2265 mmdrop(mm); 2266 if (unlikely(prev_state == TASK_DEAD)) { 2267 if (prev->sched_class->task_dead) 2268 prev->sched_class->task_dead(prev); 2269 2270 /* 2271 * Remove function-return probe instances associated with this 2272 * task and put them back on the free list. 2273 */ 2274 kprobe_flush_task(prev); 2275 put_task_struct(prev); 2276 } 2277 2278 tick_nohz_task_switch(current); 2279} 2280 2281#ifdef CONFIG_SMP 2282 2283/* rq->lock is NOT held, but preemption is disabled */ 2284static inline void post_schedule(struct rq *rq) 2285{ 2286 if (rq->post_schedule) { 2287 unsigned long flags; 2288 2289 raw_spin_lock_irqsave(&rq->lock, flags); 2290 if (rq->curr->sched_class->post_schedule) 2291 rq->curr->sched_class->post_schedule(rq); 2292 raw_spin_unlock_irqrestore(&rq->lock, flags); 2293 2294 rq->post_schedule = 0; 2295 } 2296} 2297 2298#else 2299 2300static inline void post_schedule(struct rq *rq) 2301{ 2302} 2303 2304#endif 2305 2306/** 2307 * schedule_tail - first thing a freshly forked thread must call. 2308 * @prev: the thread we just switched away from. 2309 */ 2310asmlinkage __visible void schedule_tail(struct task_struct *prev) 2311 __releases(rq->lock) 2312{ 2313 struct rq *rq = this_rq(); 2314 2315 finish_task_switch(rq, prev); 2316 2317 /* 2318 * FIXME: do we need to worry about rq being invalidated by the 2319 * task_switch? 2320 */ 2321 post_schedule(rq); 2322 2323#ifdef __ARCH_WANT_UNLOCKED_CTXSW 2324 /* In this case, finish_task_switch does not reenable preemption */ 2325 preempt_enable(); 2326#endif 2327 if (current->set_child_tid) 2328 put_user(task_pid_vnr(current), current->set_child_tid); 2329} 2330 2331/* 2332 * context_switch - switch to the new MM and the new 2333 * thread's register state. 2334 */ 2335static inline void 2336context_switch(struct rq *rq, struct task_struct *prev, 2337 struct task_struct *next) 2338{ 2339 struct mm_struct *mm, *oldmm; 2340 2341 prepare_task_switch(rq, prev, next); 2342 2343 mm = next->mm; 2344 oldmm = prev->active_mm; 2345 /* 2346 * For paravirt, this is coupled with an exit in switch_to to 2347 * combine the page table reload and the switch backend into 2348 * one hypercall. 2349 */ 2350 arch_start_context_switch(prev); 2351 2352 if (!mm) { 2353 next->active_mm = oldmm; 2354 atomic_inc(&oldmm->mm_count); 2355 enter_lazy_tlb(oldmm, next); 2356 } else 2357 switch_mm(oldmm, mm, next); 2358 2359 if (!prev->mm) { 2360 prev->active_mm = NULL; 2361 rq->prev_mm = oldmm; 2362 } 2363 /* 2364 * Since the runqueue lock will be released by the next 2365 * task (which is an invalid locking op but in the case 2366 * of the scheduler it's an obvious special-case), so we 2367 * do an early lockdep release here: 2368 */ 2369#ifndef __ARCH_WANT_UNLOCKED_CTXSW 2370 spin_release(&rq->lock.dep_map, 1, _THIS_IP_); 2371#endif 2372 2373 context_tracking_task_switch(prev, next); 2374 /* Here we just switch the register state and the stack. */ 2375 switch_to(prev, next, prev); 2376 2377 barrier(); 2378 /* 2379 * this_rq must be evaluated again because prev may have moved 2380 * CPUs since it called schedule(), thus the 'rq' on its stack 2381 * frame will be invalid. 2382 */ 2383 finish_task_switch(this_rq(), prev); 2384} 2385 2386/* 2387 * nr_running and nr_context_switches: 2388 * 2389 * externally visible scheduler statistics: current number of runnable 2390 * threads, total number of context switches performed since bootup. 2391 */ 2392unsigned long nr_running(void) 2393{ 2394 unsigned long i, sum = 0; 2395 2396 for_each_online_cpu(i) 2397 sum += cpu_rq(i)->nr_running; 2398 2399 return sum; 2400} 2401 2402unsigned long long nr_context_switches(void) 2403{ 2404 int i; 2405 unsigned long long sum = 0; 2406 2407 for_each_possible_cpu(i) 2408 sum += cpu_rq(i)->nr_switches; 2409 2410 return sum; 2411} 2412 2413unsigned long nr_iowait(void) 2414{ 2415 unsigned long i, sum = 0; 2416 2417 for_each_possible_cpu(i) 2418 sum += atomic_read(&cpu_rq(i)->nr_iowait); 2419 2420 return sum; 2421} 2422 2423unsigned long nr_iowait_cpu(int cpu) 2424{ 2425 struct rq *this = cpu_rq(cpu); 2426 return atomic_read(&this->nr_iowait); 2427} 2428 2429void get_iowait_load(unsigned long *nr_waiters, unsigned long *load) 2430{ 2431 struct rq *this = this_rq(); 2432 *nr_waiters = atomic_read(&this->nr_iowait); 2433 *load = this->cpu_load[0]; 2434} 2435 2436#ifdef CONFIG_SMP 2437 2438/* 2439 * sched_exec - execve() is a valuable balancing opportunity, because at 2440 * this point the task has the smallest effective memory and cache footprint. 2441 */ 2442void sched_exec(void) 2443{ 2444 struct task_struct *p = current; 2445 unsigned long flags; 2446 int dest_cpu; 2447 2448 raw_spin_lock_irqsave(&p->pi_lock, flags); 2449 dest_cpu = p->sched_class->select_task_rq(p, task_cpu(p), SD_BALANCE_EXEC, 0); 2450 if (dest_cpu == smp_processor_id()) 2451 goto unlock; 2452 2453 if (likely(cpu_active(dest_cpu))) { 2454 struct migration_arg arg = { p, dest_cpu }; 2455 2456 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 2457 stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg); 2458 return; 2459 } 2460unlock: 2461 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 2462} 2463 2464#endif 2465 2466DEFINE_PER_CPU(struct kernel_stat, kstat); 2467DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat); 2468 2469EXPORT_PER_CPU_SYMBOL(kstat); 2470EXPORT_PER_CPU_SYMBOL(kernel_cpustat); 2471 2472/* 2473 * Return any ns on the sched_clock that have not yet been accounted in 2474 * @p in case that task is currently running. 2475 * 2476 * Called with task_rq_lock() held on @rq. 2477 */ 2478static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq) 2479{ 2480 u64 ns = 0; 2481 2482 /* 2483 * Must be ->curr _and_ ->on_rq. If dequeued, we would 2484 * project cycles that may never be accounted to this 2485 * thread, breaking clock_gettime(). 2486 */ 2487 if (task_current(rq, p) && task_on_rq_queued(p)) { 2488 update_rq_clock(rq); 2489 ns = rq_clock_task(rq) - p->se.exec_start; 2490 if ((s64)ns < 0) 2491 ns = 0; 2492 } 2493 2494 return ns; 2495} 2496 2497unsigned long long task_delta_exec(struct task_struct *p) 2498{ 2499 unsigned long flags; 2500 struct rq *rq; 2501 u64 ns = 0; 2502 2503 rq = task_rq_lock(p, &flags); 2504 ns = do_task_delta_exec(p, rq); 2505 task_rq_unlock(rq, p, &flags); 2506 2507 return ns; 2508} 2509 2510/* 2511 * Return accounted runtime for the task. 2512 * In case the task is currently running, return the runtime plus current's 2513 * pending runtime that have not been accounted yet. 2514 */ 2515unsigned long long task_sched_runtime(struct task_struct *p) 2516{ 2517 unsigned long flags; 2518 struct rq *rq; 2519 u64 ns = 0; 2520 2521#if defined(CONFIG_64BIT) && defined(CONFIG_SMP) 2522 /* 2523 * 64-bit doesn't need locks to atomically read a 64bit value. 2524 * So we have a optimization chance when the task's delta_exec is 0. 2525 * Reading ->on_cpu is racy, but this is ok. 2526 * 2527 * If we race with it leaving cpu, we'll take a lock. So we're correct. 2528 * If we race with it entering cpu, unaccounted time is 0. This is 2529 * indistinguishable from the read occurring a few cycles earlier. 2530 * If we see ->on_cpu without ->on_rq, the task is leaving, and has 2531 * been accounted, so we're correct here as well. 2532 */ 2533 if (!p->on_cpu || !task_on_rq_queued(p)) 2534 return p->se.sum_exec_runtime; 2535#endif 2536 2537 rq = task_rq_lock(p, &flags); 2538 ns = p->se.sum_exec_runtime + do_task_delta_exec(p, rq); 2539 task_rq_unlock(rq, p, &flags); 2540 2541 return ns; 2542} 2543 2544/* 2545 * This function gets called by the timer code, with HZ frequency. 2546 * We call it with interrupts disabled. 2547 */ 2548void scheduler_tick(void) 2549{ 2550 int cpu = smp_processor_id(); 2551 struct rq *rq = cpu_rq(cpu); 2552 struct task_struct *curr = rq->curr; 2553 2554 sched_clock_tick(); 2555 2556 raw_spin_lock(&rq->lock); 2557 update_rq_clock(rq); 2558 curr->sched_class->task_tick(rq, curr, 0); 2559 update_cpu_load_active(rq); 2560 raw_spin_unlock(&rq->lock); 2561 2562 perf_event_task_tick(); 2563 2564#ifdef CONFIG_SMP 2565 rq->idle_balance = idle_cpu(cpu); 2566 trigger_load_balance(rq); 2567#endif 2568 rq_last_tick_reset(rq); 2569} 2570 2571#ifdef CONFIG_NO_HZ_FULL 2572/** 2573 * scheduler_tick_max_deferment 2574 * 2575 * Keep at least one tick per second when a single 2576 * active task is running because the scheduler doesn't 2577 * yet completely support full dynticks environment. 2578 * 2579 * This makes sure that uptime, CFS vruntime, load 2580 * balancing, etc... continue to move forward, even 2581 * with a very low granularity. 2582 * 2583 * Return: Maximum deferment in nanoseconds. 2584 */ 2585u64 scheduler_tick_max_deferment(void) 2586{ 2587 struct rq *rq = this_rq(); 2588 unsigned long next, now = ACCESS_ONCE(jiffies); 2589 2590 next = rq->last_sched_tick + HZ; 2591 2592 if (time_before_eq(next, now)) 2593 return 0; 2594 2595 return jiffies_to_nsecs(next - now); 2596} 2597#endif 2598 2599notrace unsigned long get_parent_ip(unsigned long addr) 2600{ 2601 if (in_lock_functions(addr)) { 2602 addr = CALLER_ADDR2; 2603 if (in_lock_functions(addr)) 2604 addr = CALLER_ADDR3; 2605 } 2606 return addr; 2607} 2608 2609#if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \ 2610 defined(CONFIG_PREEMPT_TRACER)) 2611 2612void preempt_count_add(int val) 2613{ 2614#ifdef CONFIG_DEBUG_PREEMPT 2615 /* 2616 * Underflow? 2617 */ 2618 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) 2619 return; 2620#endif 2621 __preempt_count_add(val); 2622#ifdef CONFIG_DEBUG_PREEMPT 2623 /* 2624 * Spinlock count overflowing soon? 2625 */ 2626 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= 2627 PREEMPT_MASK - 10); 2628#endif 2629 if (preempt_count() == val) { 2630 unsigned long ip = get_parent_ip(CALLER_ADDR1); 2631#ifdef CONFIG_DEBUG_PREEMPT 2632 current->preempt_disable_ip = ip; 2633#endif 2634 trace_preempt_off(CALLER_ADDR0, ip); 2635 } 2636} 2637EXPORT_SYMBOL(preempt_count_add); 2638NOKPROBE_SYMBOL(preempt_count_add); 2639 2640void preempt_count_sub(int val) 2641{ 2642#ifdef CONFIG_DEBUG_PREEMPT 2643 /* 2644 * Underflow? 2645 */ 2646 if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) 2647 return; 2648 /* 2649 * Is the spinlock portion underflowing? 2650 */ 2651 if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && 2652 !(preempt_count() & PREEMPT_MASK))) 2653 return; 2654#endif 2655 2656 if (preempt_count() == val) 2657 trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); 2658 __preempt_count_sub(val); 2659} 2660EXPORT_SYMBOL(preempt_count_sub); 2661NOKPROBE_SYMBOL(preempt_count_sub); 2662 2663#endif 2664 2665/* 2666 * Print scheduling while atomic bug: 2667 */ 2668static noinline void __schedule_bug(struct task_struct *prev) 2669{ 2670 if (oops_in_progress) 2671 return; 2672 2673 printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n", 2674 prev->comm, prev->pid, preempt_count()); 2675 2676 debug_show_held_locks(prev); 2677 print_modules(); 2678 if (irqs_disabled()) 2679 print_irqtrace_events(prev); 2680#ifdef CONFIG_DEBUG_PREEMPT 2681 if (in_atomic_preempt_off()) { 2682 pr_err("Preemption disabled at:"); 2683 print_ip_sym(current->preempt_disable_ip); 2684 pr_cont("\n"); 2685 } 2686#endif 2687 dump_stack(); 2688 add_taint(TAINT_WARN, LOCKDEP_STILL_OK); 2689} 2690 2691/* 2692 * Various schedule()-time debugging checks and statistics: 2693 */ 2694static inline void schedule_debug(struct task_struct *prev) 2695{ 2696 /* 2697 * Test if we are atomic. Since do_exit() needs to call into 2698 * schedule() atomically, we ignore that path. Otherwise whine 2699 * if we are scheduling when we should not. 2700 */ 2701 if (unlikely(in_atomic_preempt_off() && prev->state != TASK_DEAD)) 2702 __schedule_bug(prev); 2703 rcu_sleep_check(); 2704 2705 profile_hit(SCHED_PROFILING, __builtin_return_address(0)); 2706 2707 schedstat_inc(this_rq(), sched_count); 2708} 2709 2710/* 2711 * Pick up the highest-prio task: 2712 */ 2713static inline struct task_struct * 2714pick_next_task(struct rq *rq, struct task_struct *prev) 2715{ 2716 const struct sched_class *class = &fair_sched_class; 2717 struct task_struct *p; 2718 2719 /* 2720 * Optimization: we know that if all tasks are in 2721 * the fair class we can call that function directly: 2722 */ 2723 if (likely(prev->sched_class == class && 2724 rq->nr_running == rq->cfs.h_nr_running)) { 2725 p = fair_sched_class.pick_next_task(rq, prev); 2726 if (unlikely(p == RETRY_TASK)) 2727 goto again; 2728 2729 /* assumes fair_sched_class->next == idle_sched_class */ 2730 if (unlikely(!p)) 2731 p = idle_sched_class.pick_next_task(rq, prev); 2732 2733 return p; 2734 } 2735 2736again: 2737 for_each_class(class) { 2738 p = class->pick_next_task(rq, prev); 2739 if (p) { 2740 if (unlikely(p == RETRY_TASK)) 2741 goto again; 2742 return p; 2743 } 2744 } 2745 2746 BUG(); /* the idle class will always have a runnable task */ 2747} 2748 2749/* 2750 * __schedule() is the main scheduler function. 2751 * 2752 * The main means of driving the scheduler and thus entering this function are: 2753 * 2754 * 1. Explicit blocking: mutex, semaphore, waitqueue, etc. 2755 * 2756 * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return 2757 * paths. For example, see arch/x86/entry_64.S. 2758 * 2759 * To drive preemption between tasks, the scheduler sets the flag in timer 2760 * interrupt handler scheduler_tick(). 2761 * 2762 * 3. Wakeups don't really cause entry into schedule(). They add a 2763 * task to the run-queue and that's it. 2764 * 2765 * Now, if the new task added to the run-queue preempts the current 2766 * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets 2767 * called on the nearest possible occasion: 2768 * 2769 * - If the kernel is preemptible (CONFIG_PREEMPT=y): 2770 * 2771 * - in syscall or exception context, at the next outmost 2772 * preempt_enable(). (this might be as soon as the wake_up()'s 2773 * spin_unlock()!) 2774 * 2775 * - in IRQ context, return from interrupt-handler to 2776 * preemptible context 2777 * 2778 * - If the kernel is not preemptible (CONFIG_PREEMPT is not set) 2779 * then at the next: 2780 * 2781 * - cond_resched() call 2782 * - explicit schedule() call 2783 * - return from syscall or exception to user-space 2784 * - return from interrupt-handler to user-space 2785 */ 2786static void __sched __schedule(void) 2787{ 2788 struct task_struct *prev, *next; 2789 unsigned long *switch_count; 2790 struct rq *rq; 2791 int cpu; 2792 2793need_resched: 2794 preempt_disable(); 2795 cpu = smp_processor_id(); 2796 rq = cpu_rq(cpu); 2797 rcu_note_context_switch(cpu); 2798 prev = rq->curr; 2799 2800 schedule_debug(prev); 2801 2802 if (sched_feat(HRTICK)) 2803 hrtick_clear(rq); 2804 2805 /* 2806 * Make sure that signal_pending_state()->signal_pending() below 2807 * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE) 2808 * done by the caller to avoid the race with signal_wake_up(). 2809 */ 2810 smp_mb__before_spinlock(); 2811 raw_spin_lock_irq(&rq->lock); 2812 2813 switch_count = &prev->nivcsw; 2814 if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { 2815 if (unlikely(signal_pending_state(prev->state, prev))) { 2816 prev->state = TASK_RUNNING; 2817 } else { 2818 deactivate_task(rq, prev, DEQUEUE_SLEEP); 2819 prev->on_rq = 0; 2820 2821 /* 2822 * If a worker went to sleep, notify and ask workqueue 2823 * whether it wants to wake up a task to maintain 2824 * concurrency. 2825 */ 2826 if (prev->flags & PF_WQ_WORKER) { 2827 struct task_struct *to_wakeup; 2828 2829 to_wakeup = wq_worker_sleeping(prev, cpu); 2830 if (to_wakeup) 2831 try_to_wake_up_local(to_wakeup); 2832 } 2833 } 2834 switch_count = &prev->nvcsw; 2835 } 2836 2837 if (task_on_rq_queued(prev) || rq->skip_clock_update < 0) 2838 update_rq_clock(rq); 2839 2840 next = pick_next_task(rq, prev); 2841 clear_tsk_need_resched(prev); 2842 clear_preempt_need_resched(); 2843 rq->skip_clock_update = 0; 2844 2845 if (likely(prev != next)) { 2846 rq->nr_switches++; 2847 rq->curr = next; 2848 ++*switch_count; 2849 2850 context_switch(rq, prev, next); /* unlocks the rq */ 2851 /* 2852 * The context switch have flipped the stack from under us 2853 * and restored the local variables which were saved when 2854 * this task called schedule() in the past. prev == current 2855 * is still correct, but it can be moved to another cpu/rq. 2856 */ 2857 cpu = smp_processor_id(); 2858 rq = cpu_rq(cpu); 2859 } else 2860 raw_spin_unlock_irq(&rq->lock); 2861 2862 post_schedule(rq); 2863 2864 sched_preempt_enable_no_resched(); 2865 if (need_resched()) 2866 goto need_resched; 2867} 2868 2869static inline void sched_submit_work(struct task_struct *tsk) 2870{ 2871 if (!tsk->state || tsk_is_pi_blocked(tsk)) 2872 return; 2873 /* 2874 * If we are going to sleep and we have plugged IO queued, 2875 * make sure to submit it to avoid deadlocks. 2876 */ 2877 if (blk_needs_flush_plug(tsk)) 2878 blk_schedule_flush_plug(tsk); 2879} 2880 2881asmlinkage __visible void __sched schedule(void) 2882{ 2883 struct task_struct *tsk = current; 2884 2885 sched_submit_work(tsk); 2886 __schedule(); 2887} 2888EXPORT_SYMBOL(schedule); 2889 2890#ifdef CONFIG_CONTEXT_TRACKING 2891asmlinkage __visible void __sched schedule_user(void) 2892{ 2893 /* 2894 * If we come here after a random call to set_need_resched(), 2895 * or we have been woken up remotely but the IPI has not yet arrived, 2896 * we haven't yet exited the RCU idle mode. Do it here manually until 2897 * we find a better solution. 2898 */ 2899 user_exit(); 2900 schedule(); 2901 user_enter(); 2902} 2903#endif 2904 2905/** 2906 * schedule_preempt_disabled - called with preemption disabled 2907 * 2908 * Returns with preemption disabled. Note: preempt_count must be 1 2909 */ 2910void __sched schedule_preempt_disabled(void) 2911{ 2912 sched_preempt_enable_no_resched(); 2913 schedule(); 2914 preempt_disable(); 2915} 2916 2917#ifdef CONFIG_PREEMPT 2918/* 2919 * this is the entry point to schedule() from in-kernel preemption 2920 * off of preempt_enable. Kernel preemptions off return from interrupt 2921 * occur there and call schedule directly. 2922 */ 2923asmlinkage __visible void __sched notrace preempt_schedule(void) 2924{ 2925 /* 2926 * If there is a non-zero preempt_count or interrupts are disabled, 2927 * we do not want to preempt the current task. Just return.. 2928 */ 2929 if (likely(!preemptible())) 2930 return; 2931 2932 do { 2933 __preempt_count_add(PREEMPT_ACTIVE); 2934 __schedule(); 2935 __preempt_count_sub(PREEMPT_ACTIVE); 2936 2937 /* 2938 * Check again in case we missed a preemption opportunity 2939 * between schedule and now. 2940 */ 2941 barrier(); 2942 } while (need_resched()); 2943} 2944NOKPROBE_SYMBOL(preempt_schedule); 2945EXPORT_SYMBOL(preempt_schedule); 2946#endif /* CONFIG_PREEMPT */ 2947 2948/* 2949 * this is the entry point to schedule() from kernel preemption 2950 * off of irq context. 2951 * Note, that this is called and return with irqs disabled. This will 2952 * protect us against recursive calling from irq. 2953 */ 2954asmlinkage __visible void __sched preempt_schedule_irq(void) 2955{ 2956 enum ctx_state prev_state; 2957 2958 /* Catch callers which need to be fixed */ 2959 BUG_ON(preempt_count() || !irqs_disabled()); 2960 2961 prev_state = exception_enter(); 2962 2963 do { 2964 __preempt_count_add(PREEMPT_ACTIVE); 2965 local_irq_enable(); 2966 __schedule(); 2967 local_irq_disable(); 2968 __preempt_count_sub(PREEMPT_ACTIVE); 2969 2970 /* 2971 * Check again in case we missed a preemption opportunity 2972 * between schedule and now. 2973 */ 2974 barrier(); 2975 } while (need_resched()); 2976 2977 exception_exit(prev_state); 2978} 2979 2980int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags, 2981 void *key) 2982{ 2983 return try_to_wake_up(curr->private, mode, wake_flags); 2984} 2985EXPORT_SYMBOL(default_wake_function); 2986 2987#ifdef CONFIG_RT_MUTEXES 2988 2989/* 2990 * rt_mutex_setprio - set the current priority of a task 2991 * @p: task 2992 * @prio: prio value (kernel-internal form) 2993 * 2994 * This function changes the 'effective' priority of a task. It does 2995 * not touch ->normal_prio like __setscheduler(). 2996 * 2997 * Used by the rt_mutex code to implement priority inheritance 2998 * logic. Call site only calls if the priority of the task changed. 2999 */ 3000void rt_mutex_setprio(struct task_struct *p, int prio) 3001{ 3002 int oldprio, queued, running, enqueue_flag = 0; 3003 struct rq *rq; 3004 const struct sched_class *prev_class; 3005 3006 BUG_ON(prio > MAX_PRIO); 3007 3008 rq = __task_rq_lock(p); 3009 3010 /* 3011 * Idle task boosting is a nono in general. There is one 3012 * exception, when PREEMPT_RT and NOHZ is active: 3013 * 3014 * The idle task calls get_next_timer_interrupt() and holds 3015 * the timer wheel base->lock on the CPU and another CPU wants 3016 * to access the timer (probably to cancel it). We can safely 3017 * ignore the boosting request, as the idle CPU runs this code 3018 * with interrupts disabled and will complete the lock 3019 * protected section without being interrupted. So there is no 3020 * real need to boost. 3021 */ 3022 if (unlikely(p == rq->idle)) { 3023 WARN_ON(p != rq->curr); 3024 WARN_ON(p->pi_blocked_on); 3025 goto out_unlock; 3026 } 3027 3028 trace_sched_pi_setprio(p, prio); 3029 oldprio = p->prio; 3030 prev_class = p->sched_class; 3031 queued = task_on_rq_queued(p); 3032 running = task_current(rq, p); 3033 if (queued) 3034 dequeue_task(rq, p, 0); 3035 if (running) 3036 put_prev_task(rq, p); 3037 3038 /* 3039 * Boosting condition are: 3040 * 1. -rt task is running and holds mutex A 3041 * --> -dl task blocks on mutex A 3042 * 3043 * 2. -dl task is running and holds mutex A 3044 * --> -dl task blocks on mutex A and could preempt the 3045 * running task 3046 */ 3047 if (dl_prio(prio)) { 3048 struct task_struct *pi_task = rt_mutex_get_top_task(p); 3049 if (!dl_prio(p->normal_prio) || 3050 (pi_task && dl_entity_preempt(&pi_task->dl, &p->dl))) { 3051 p->dl.dl_boosted = 1; 3052 p->dl.dl_throttled = 0; 3053 enqueue_flag = ENQUEUE_REPLENISH; 3054 } else 3055 p->dl.dl_boosted = 0; 3056 p->sched_class = &dl_sched_class; 3057 } else if (rt_prio(prio)) { 3058 if (dl_prio(oldprio)) 3059 p->dl.dl_boosted = 0; 3060 if (oldprio < prio) 3061 enqueue_flag = ENQUEUE_HEAD; 3062 p->sched_class = &rt_sched_class; 3063 } else { 3064 if (dl_prio(oldprio)) 3065 p->dl.dl_boosted = 0; 3066 p->sched_class = &fair_sched_class; 3067 } 3068 3069 p->prio = prio; 3070 3071 if (running) 3072 p->sched_class->set_curr_task(rq); 3073 if (queued) 3074 enqueue_task(rq, p, enqueue_flag); 3075 3076 check_class_changed(rq, p, prev_class, oldprio); 3077out_unlock: 3078 __task_rq_unlock(rq); 3079} 3080#endif 3081 3082void set_user_nice(struct task_struct *p, long nice) 3083{ 3084 int old_prio, delta, queued; 3085 unsigned long flags; 3086 struct rq *rq; 3087 3088 if (task_nice(p) == nice || nice < MIN_NICE || nice > MAX_NICE) 3089 return; 3090 /* 3091 * We have to be careful, if called from sys_setpriority(), 3092 * the task might be in the middle of scheduling on another CPU. 3093 */ 3094 rq = task_rq_lock(p, &flags); 3095 /* 3096 * The RT priorities are set via sched_setscheduler(), but we still 3097 * allow the 'normal' nice value to be set - but as expected 3098 * it wont have any effect on scheduling until the task is 3099 * SCHED_DEADLINE, SCHED_FIFO or SCHED_RR: 3100 */ 3101 if (task_has_dl_policy(p) || task_has_rt_policy(p)) { 3102 p->static_prio = NICE_TO_PRIO(nice); 3103 goto out_unlock; 3104 } 3105 queued = task_on_rq_queued(p); 3106 if (queued) 3107 dequeue_task(rq, p, 0); 3108 3109 p->static_prio = NICE_TO_PRIO(nice); 3110 set_load_weight(p); 3111 old_prio = p->prio; 3112 p->prio = effective_prio(p); 3113 delta = p->prio - old_prio; 3114 3115 if (queued) { 3116 enqueue_task(rq, p, 0); 3117 /* 3118 * If the task increased its priority or is running and 3119 * lowered its priority, then reschedule its CPU: 3120 */ 3121 if (delta < 0 || (delta > 0 && task_running(rq, p))) 3122 resched_curr(rq); 3123 } 3124out_unlock: 3125 task_rq_unlock(rq, p, &flags); 3126} 3127EXPORT_SYMBOL(set_user_nice); 3128 3129/* 3130 * can_nice - check if a task can reduce its nice value 3131 * @p: task 3132 * @nice: nice value 3133 */ 3134int can_nice(const struct task_struct *p, const int nice) 3135{ 3136 /* convert nice value [19,-20] to rlimit style value [1,40] */ 3137 int nice_rlim = nice_to_rlimit(nice); 3138 3139 return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) || 3140 capable(CAP_SYS_NICE)); 3141} 3142 3143#ifdef __ARCH_WANT_SYS_NICE 3144 3145/* 3146 * sys_nice - change the priority of the current process. 3147 * @increment: priority increment 3148 * 3149 * sys_setpriority is a more generic, but much slower function that 3150 * does similar things. 3151 */ 3152SYSCALL_DEFINE1(nice, int, increment) 3153{ 3154 long nice, retval; 3155 3156 /* 3157 * Setpriority might change our priority at the same moment. 3158 * We don't have to worry. Conceptually one call occurs first 3159 * and we have a single winner. 3160 */ 3161 increment = clamp(increment, -NICE_WIDTH, NICE_WIDTH); 3162 nice = task_nice(current) + increment; 3163 3164 nice = clamp_val(nice, MIN_NICE, MAX_NICE); 3165 if (increment < 0 && !can_nice(current, nice)) 3166 return -EPERM; 3167 3168 retval = security_task_setnice(current, nice); 3169 if (retval) 3170 return retval; 3171 3172 set_user_nice(current, nice); 3173 return 0; 3174} 3175 3176#endif 3177 3178/** 3179 * task_prio - return the priority value of a given task. 3180 * @p: the task in question. 3181 * 3182 * Return: The priority value as seen by users in /proc. 3183 * RT tasks are offset by -200. Normal tasks are centered 3184 * around 0, value goes from -16 to +15. 3185 */ 3186int task_prio(const struct task_struct *p) 3187{ 3188 return p->prio - MAX_RT_PRIO; 3189} 3190 3191/** 3192 * idle_cpu - is a given cpu idle currently? 3193 * @cpu: the processor in question. 3194 * 3195 * Return: 1 if the CPU is currently idle. 0 otherwise. 3196 */ 3197int idle_cpu(int cpu) 3198{ 3199 struct rq *rq = cpu_rq(cpu); 3200 3201 if (rq->curr != rq->idle) 3202 return 0; 3203 3204 if (rq->nr_running) 3205 return 0; 3206 3207#ifdef CONFIG_SMP 3208 if (!llist_empty(&rq->wake_list)) 3209 return 0; 3210#endif 3211 3212 return 1; 3213} 3214 3215/** 3216 * idle_task - return the idle task for a given cpu. 3217 * @cpu: the processor in question. 3218 * 3219 * Return: The idle task for the cpu @cpu. 3220 */ 3221struct task_struct *idle_task(int cpu) 3222{ 3223 return cpu_rq(cpu)->idle; 3224} 3225 3226/** 3227 * find_process_by_pid - find a process with a matching PID value. 3228 * @pid: the pid in question. 3229 * 3230 * The task of @pid, if found. %NULL otherwise. 3231 */ 3232static struct task_struct *find_process_by_pid(pid_t pid) 3233{ 3234 return pid ? find_task_by_vpid(pid) : current; 3235} 3236 3237/* 3238 * This function initializes the sched_dl_entity of a newly becoming 3239 * SCHED_DEADLINE task. 3240 * 3241 * Only the static values are considered here, the actual runtime and the 3242 * absolute deadline will be properly calculated when the task is enqueued 3243 * for the first time with its new policy. 3244 */ 3245static void 3246__setparam_dl(struct task_struct *p, const struct sched_attr *attr) 3247{ 3248 struct sched_dl_entity *dl_se = &p->dl; 3249 3250 init_dl_task_timer(dl_se); 3251 dl_se->dl_runtime = attr->sched_runtime; 3252 dl_se->dl_deadline = attr->sched_deadline; 3253 dl_se->dl_period = attr->sched_period ?: dl_se->dl_deadline; 3254 dl_se->flags = attr->sched_flags; 3255 dl_se->dl_bw = to_ratio(dl_se->dl_period, dl_se->dl_runtime); 3256 dl_se->dl_throttled = 0; 3257 dl_se->dl_new = 1; 3258 dl_se->dl_yielded = 0; 3259} 3260 3261/* 3262 * sched_setparam() passes in -1 for its policy, to let the functions 3263 * it calls know not to change it. 3264 */ 3265#define SETPARAM_POLICY -1 3266 3267static void __setscheduler_params(struct task_struct *p, 3268 const struct sched_attr *attr) 3269{ 3270 int policy = attr->sched_policy; 3271 3272 if (policy == SETPARAM_POLICY) 3273 policy = p->policy; 3274 3275 p->policy = policy; 3276 3277 if (dl_policy(policy)) 3278 __setparam_dl(p, attr); 3279 else if (fair_policy(policy)) 3280 p->static_prio = NICE_TO_PRIO(attr->sched_nice); 3281 3282 /* 3283 * __sched_setscheduler() ensures attr->sched_priority == 0 when 3284 * !rt_policy. Always setting this ensures that things like 3285 * getparam()/getattr() don't report silly values for !rt tasks. 3286 */ 3287 p->rt_priority = attr->sched_priority; 3288 p->normal_prio = normal_prio(p); 3289 set_load_weight(p); 3290} 3291 3292/* Actually do priority change: must hold pi & rq lock. */ 3293static void __setscheduler(struct rq *rq, struct task_struct *p, 3294 const struct sched_attr *attr) 3295{ 3296 __setscheduler_params(p, attr); 3297 3298 /* 3299 * If we get here, there was no pi waiters boosting the 3300 * task. It is safe to use the normal prio. 3301 */ 3302 p->prio = normal_prio(p); 3303 3304 if (dl_prio(p->prio)) 3305 p->sched_class = &dl_sched_class; 3306 else if (rt_prio(p->prio)) 3307 p->sched_class = &rt_sched_class; 3308 else 3309 p->sched_class = &fair_sched_class; 3310} 3311 3312static void 3313__getparam_dl(struct task_struct *p, struct sched_attr *attr) 3314{ 3315 struct sched_dl_entity *dl_se = &p->dl; 3316 3317 attr->sched_priority = p->rt_priority; 3318 attr->sched_runtime = dl_se->dl_runtime; 3319 attr->sched_deadline = dl_se->dl_deadline; 3320 attr->sched_period = dl_se->dl_period; 3321 attr->sched_flags = dl_se->flags; 3322} 3323 3324/* 3325 * This function validates the new parameters of a -deadline task. 3326 * We ask for the deadline not being zero, and greater or equal 3327 * than the runtime, as well as the period of being zero or 3328 * greater than deadline. Furthermore, we have to be sure that 3329 * user parameters are above the internal resolution of 1us (we 3330 * check sched_runtime only since it is always the smaller one) and 3331 * below 2^63 ns (we have to check both sched_deadline and 3332 * sched_period, as the latter can be zero). 3333 */ 3334static bool 3335__checkparam_dl(const struct sched_attr *attr) 3336{ 3337 /* deadline != 0 */ 3338 if (attr->sched_deadline == 0) 3339 return false; 3340 3341 /* 3342 * Since we truncate DL_SCALE bits, make sure we're at least 3343 * that big. 3344 */ 3345 if (attr->sched_runtime < (1ULL << DL_SCALE)) 3346 return false; 3347 3348 /* 3349 * Since we use the MSB for wrap-around and sign issues, make 3350 * sure it's not set (mind that period can be equal to zero). 3351 */ 3352 if (attr->sched_deadline & (1ULL << 63) || 3353 attr->sched_period & (1ULL << 63)) 3354 return false; 3355 3356 /* runtime <= deadline <= period (if period != 0) */ 3357 if ((attr->sched_period != 0 && 3358 attr->sched_period < attr->sched_deadline) || 3359 attr->sched_deadline < attr->sched_runtime) 3360 return false; 3361 3362 return true; 3363} 3364 3365/* 3366 * check the target process has a UID that matches the current process's 3367 */ 3368static bool check_same_owner(struct task_struct *p) 3369{ 3370 const struct cred *cred = current_cred(), *pcred; 3371 bool match; 3372 3373 rcu_read_lock(); 3374 pcred = __task_cred(p); 3375 match = (uid_eq(cred->euid, pcred->euid) || 3376 uid_eq(cred->euid, pcred->uid)); 3377 rcu_read_unlock(); 3378 return match; 3379} 3380 3381static int __sched_setscheduler(struct task_struct *p, 3382 const struct sched_attr *attr, 3383 bool user) 3384{ 3385 int newprio = dl_policy(attr->sched_policy) ? MAX_DL_PRIO - 1 : 3386 MAX_RT_PRIO - 1 - attr->sched_priority; 3387 int retval, oldprio, oldpolicy = -1, queued, running; 3388 int policy = attr->sched_policy; 3389 unsigned long flags; 3390 const struct sched_class *prev_class; 3391 struct rq *rq; 3392 int reset_on_fork; 3393 3394 /* may grab non-irq protected spin_locks */ 3395 BUG_ON(in_interrupt()); 3396recheck: 3397 /* double check policy once rq lock held */ 3398 if (policy < 0) { 3399 reset_on_fork = p->sched_reset_on_fork; 3400 policy = oldpolicy = p->policy; 3401 } else { 3402 reset_on_fork = !!(attr->sched_flags & SCHED_FLAG_RESET_ON_FORK); 3403 3404 if (policy != SCHED_DEADLINE && 3405 policy != SCHED_FIFO && policy != SCHED_RR && 3406 policy != SCHED_NORMAL && policy != SCHED_BATCH && 3407 policy != SCHED_IDLE) 3408 return -EINVAL; 3409 } 3410 3411 if (attr->sched_flags & ~(SCHED_FLAG_RESET_ON_FORK)) 3412 return -EINVAL; 3413 3414 /* 3415 * Valid priorities for SCHED_FIFO and SCHED_RR are 3416 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL, 3417 * SCHED_BATCH and SCHED_IDLE is 0. 3418 */ 3419 if ((p->mm && attr->sched_priority > MAX_USER_RT_PRIO-1) || 3420 (!p->mm && attr->sched_priority > MAX_RT_PRIO-1)) 3421 return -EINVAL; 3422 if ((dl_policy(policy) && !__checkparam_dl(attr)) || 3423 (rt_policy(policy) != (attr->sched_priority != 0))) 3424 return -EINVAL; 3425 3426 /* 3427 * Allow unprivileged RT tasks to decrease priority: 3428 */ 3429 if (user && !capable(CAP_SYS_NICE)) { 3430 if (fair_policy(policy)) { 3431 if (attr->sched_nice < task_nice(p) && 3432 !can_nice(p, attr->sched_nice)) 3433 return -EPERM; 3434 } 3435 3436 if (rt_policy(policy)) { 3437 unsigned long rlim_rtprio = 3438 task_rlimit(p, RLIMIT_RTPRIO); 3439 3440 /* can't set/change the rt policy */ 3441 if (policy != p->policy && !rlim_rtprio) 3442 return -EPERM; 3443 3444 /* can't increase priority */ 3445 if (attr->sched_priority > p->rt_priority && 3446 attr->sched_priority > rlim_rtprio) 3447 return -EPERM; 3448 } 3449 3450 /* 3451 * Can't set/change SCHED_DEADLINE policy at all for now 3452 * (safest behavior); in the future we would like to allow 3453 * unprivileged DL tasks to increase their relative deadline 3454 * or reduce their runtime (both ways reducing utilization) 3455 */ 3456 if (dl_policy(policy)) 3457 return -EPERM; 3458 3459 /* 3460 * Treat SCHED_IDLE as nice 20. Only allow a switch to 3461 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it. 3462 */ 3463 if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) { 3464 if (!can_nice(p, task_nice(p))) 3465 return -EPERM; 3466 } 3467 3468 /* can't change other user's priorities */ 3469 if (!check_same_owner(p)) 3470 return -EPERM; 3471 3472 /* Normal users shall not reset the sched_reset_on_fork flag */ 3473 if (p->sched_reset_on_fork && !reset_on_fork) 3474 return -EPERM; 3475 } 3476 3477 if (user) { 3478 retval = security_task_setscheduler(p); 3479 if (retval) 3480 return retval; 3481 } 3482 3483 /* 3484 * make sure no PI-waiters arrive (or leave) while we are 3485 * changing the priority of the task: 3486 * 3487 * To be able to change p->policy safely, the appropriate 3488 * runqueue lock must be held. 3489 */ 3490 rq = task_rq_lock(p, &flags); 3491 3492 /* 3493 * Changing the policy of the stop threads its a very bad idea 3494 */ 3495 if (p == rq->stop) { 3496 task_rq_unlock(rq, p, &flags); 3497 return -EINVAL; 3498 } 3499 3500 /* 3501 * If not changing anything there's no need to proceed further, 3502 * but store a possible modification of reset_on_fork. 3503 */ 3504 if (unlikely(policy == p->policy)) { 3505 if (fair_policy(policy) && attr->sched_nice != task_nice(p)) 3506 goto change; 3507 if (rt_policy(policy) && attr->sched_priority != p->rt_priority) 3508 goto change; 3509 if (dl_policy(policy)) 3510 goto change; 3511 3512 p->sched_reset_on_fork = reset_on_fork; 3513 task_rq_unlock(rq, p, &flags); 3514 return 0; 3515 } 3516change: 3517 3518 if (user) { 3519#ifdef CONFIG_RT_GROUP_SCHED 3520 /* 3521 * Do not allow realtime tasks into groups that have no runtime 3522 * assigned. 3523 */ 3524 if (rt_bandwidth_enabled() && rt_policy(policy) && 3525 task_group(p)->rt_bandwidth.rt_runtime == 0 && 3526 !task_group_is_autogroup(task_group(p))) { 3527 task_rq_unlock(rq, p, &flags); 3528 return -EPERM; 3529 } 3530#endif 3531#ifdef CONFIG_SMP 3532 if (dl_bandwidth_enabled() && dl_policy(policy)) { 3533 cpumask_t *span = rq->rd->span; 3534 3535 /* 3536 * Don't allow tasks with an affinity mask smaller than 3537 * the entire root_domain to become SCHED_DEADLINE. We 3538 * will also fail if there's no bandwidth available. 3539 */ 3540 if (!cpumask_subset(span, &p->cpus_allowed) || 3541 rq->rd->dl_bw.bw == 0) { 3542 task_rq_unlock(rq, p, &flags); 3543 return -EPERM; 3544 } 3545 } 3546#endif 3547 } 3548 3549 /* recheck policy now with rq lock held */ 3550 if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { 3551 policy = oldpolicy = -1; 3552 task_rq_unlock(rq, p, &flags); 3553 goto recheck; 3554 } 3555 3556 /* 3557 * If setscheduling to SCHED_DEADLINE (or changing the parameters 3558 * of a SCHED_DEADLINE task) we need to check if enough bandwidth 3559 * is available. 3560 */ 3561 if ((dl_policy(policy) || dl_task(p)) && dl_overflow(p, policy, attr)) { 3562 task_rq_unlock(rq, p, &flags); 3563 return -EBUSY; 3564 } 3565 3566 p->sched_reset_on_fork = reset_on_fork; 3567 oldprio = p->prio; 3568 3569 /* 3570 * Special case for priority boosted tasks. 3571 * 3572 * If the new priority is lower or equal (user space view) 3573 * than the current (boosted) priority, we just store the new 3574 * normal parameters and do not touch the scheduler class and 3575 * the runqueue. This will be done when the task deboost 3576 * itself. 3577 */ 3578 if (rt_mutex_check_prio(p, newprio)) { 3579 __setscheduler_params(p, attr); 3580 task_rq_unlock(rq, p, &flags); 3581 return 0; 3582 } 3583 3584 queued = task_on_rq_queued(p); 3585 running = task_current(rq, p); 3586 if (queued) 3587 dequeue_task(rq, p, 0); 3588 if (running) 3589 put_prev_task(rq, p); 3590 3591 prev_class = p->sched_class; 3592 __setscheduler(rq, p, attr); 3593 3594 if (running) 3595 p->sched_class->set_curr_task(rq); 3596 if (queued) { 3597 /* 3598 * We enqueue to tail when the priority of a task is 3599 * increased (user space view). 3600 */ 3601 enqueue_task(rq, p, oldprio <= p->prio ? ENQUEUE_HEAD : 0); 3602 } 3603 3604 check_class_changed(rq, p, prev_class, oldprio); 3605 task_rq_unlock(rq, p, &flags); 3606 3607 rt_mutex_adjust_pi(p); 3608 3609 return 0; 3610} 3611 3612static int _sched_setscheduler(struct task_struct *p, int policy, 3613 const struct sched_param *param, bool check) 3614{ 3615 struct sched_attr attr = { 3616 .sched_policy = policy, 3617 .sched_priority = param->sched_priority, 3618 .sched_nice = PRIO_TO_NICE(p->static_prio), 3619 }; 3620 3621 /* Fixup the legacy SCHED_RESET_ON_FORK hack. */ 3622 if ((policy != SETPARAM_POLICY) && (policy & SCHED_RESET_ON_FORK)) { 3623 attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK; 3624 policy &= ~SCHED_RESET_ON_FORK; 3625 attr.sched_policy = policy; 3626 } 3627 3628 return __sched_setscheduler(p, &attr, check); 3629} 3630/** 3631 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. 3632 * @p: the task in question. 3633 * @policy: new policy. 3634 * @param: structure containing the new RT priority. 3635 * 3636 * Return: 0 on success. An error code otherwise. 3637 * 3638 * NOTE that the task may be already dead. 3639 */ 3640int sched_setscheduler(struct task_struct *p, int policy, 3641 const struct sched_param *param) 3642{ 3643 return _sched_setscheduler(p, policy, param, true); 3644} 3645EXPORT_SYMBOL_GPL(sched_setscheduler); 3646 3647int sched_setattr(struct task_struct *p, const struct sched_attr *attr) 3648{ 3649 return __sched_setscheduler(p, attr, true); 3650} 3651EXPORT_SYMBOL_GPL(sched_setattr); 3652 3653/** 3654 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace. 3655 * @p: the task in question. 3656 * @policy: new policy. 3657 * @param: structure containing the new RT priority. 3658 * 3659 * Just like sched_setscheduler, only don't bother checking if the 3660 * current context has permission. For example, this is needed in 3661 * stop_machine(): we create temporary high priority worker threads, 3662 * but our caller might not have that capability. 3663 * 3664 * Return: 0 on success. An error code otherwise. 3665 */ 3666int sched_setscheduler_nocheck(struct task_struct *p, int policy, 3667 const struct sched_param *param) 3668{ 3669 return _sched_setscheduler(p, policy, param, false); 3670} 3671 3672static int 3673do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) 3674{ 3675 struct sched_param lparam; 3676 struct task_struct *p; 3677 int retval; 3678 3679 if (!param || pid < 0) 3680 return -EINVAL; 3681 if (copy_from_user(&lparam, param, sizeof(struct sched_param))) 3682 return -EFAULT; 3683 3684 rcu_read_lock(); 3685 retval = -ESRCH; 3686 p = find_process_by_pid(pid); 3687 if (p != NULL) 3688 retval = sched_setscheduler(p, policy, &lparam); 3689 rcu_read_unlock(); 3690 3691 return retval; 3692} 3693 3694/* 3695 * Mimics kernel/events/core.c perf_copy_attr(). 3696 */ 3697static int sched_copy_attr(struct sched_attr __user *uattr, 3698 struct sched_attr *attr) 3699{ 3700 u32 size; 3701 int ret; 3702 3703 if (!access_ok(VERIFY_WRITE, uattr, SCHED_ATTR_SIZE_VER0)) 3704 return -EFAULT; 3705 3706 /* 3707 * zero the full structure, so that a short copy will be nice. 3708 */ 3709 memset(attr, 0, sizeof(*attr)); 3710 3711 ret = get_user(size, &uattr->size); 3712 if (ret) 3713 return ret; 3714 3715 if (size > PAGE_SIZE) /* silly large */ 3716 goto err_size; 3717 3718 if (!size) /* abi compat */ 3719 size = SCHED_ATTR_SIZE_VER0; 3720 3721 if (size < SCHED_ATTR_SIZE_VER0) 3722 goto err_size; 3723 3724 /* 3725 * If we're handed a bigger struct than we know of, 3726 * ensure all the unknown bits are 0 - i.e. new 3727 * user-space does not rely on any kernel feature 3728 * extensions we dont know about yet. 3729 */ 3730 if (size > sizeof(*attr)) { 3731 unsigned char __user *addr; 3732 unsigned char __user *end; 3733 unsigned char val; 3734 3735 addr = (void __user *)uattr + sizeof(*attr); 3736 end = (void __user *)uattr + size; 3737 3738 for (; addr < end; addr++) { 3739 ret = get_user(val, addr); 3740 if (ret) 3741 return ret; 3742 if (val) 3743 goto err_size; 3744 } 3745 size = sizeof(*attr); 3746 } 3747 3748 ret = copy_from_user(attr, uattr, size); 3749 if (ret) 3750 return -EFAULT; 3751 3752 /* 3753 * XXX: do we want to be lenient like existing syscalls; or do we want 3754 * to be strict and return an error on out-of-bounds values? 3755 */ 3756 attr->sched_nice = clamp(attr->sched_nice, MIN_NICE, MAX_NICE); 3757 3758 return 0; 3759 3760err_size: 3761 put_user(sizeof(*attr), &uattr->size); 3762 return -E2BIG; 3763} 3764 3765/** 3766 * sys_sched_setscheduler - set/change the scheduler policy and RT priority 3767 * @pid: the pid in question. 3768 * @policy: new policy. 3769 * @param: structure containing the new RT priority. 3770 * 3771 * Return: 0 on success. An error code otherwise. 3772 */ 3773SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy, 3774 struct sched_param __user *, param) 3775{ 3776 /* negative values for policy are not valid */ 3777 if (policy < 0) 3778 return -EINVAL; 3779 3780 return do_sched_setscheduler(pid, policy, param); 3781} 3782 3783/** 3784 * sys_sched_setparam - set/change the RT priority of a thread 3785 * @pid: the pid in question. 3786 * @param: structure containing the new RT priority. 3787 * 3788 * Return: 0 on success. An error code otherwise. 3789 */ 3790SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param) 3791{ 3792 return do_sched_setscheduler(pid, SETPARAM_POLICY, param); 3793} 3794 3795/** 3796 * sys_sched_setattr - same as above, but with extended sched_attr 3797 * @pid: the pid in question. 3798 * @uattr: structure containing the extended parameters. 3799 * @flags: for future extension. 3800 */ 3801SYSCALL_DEFINE3(sched_setattr, pid_t, pid, struct sched_attr __user *, uattr, 3802 unsigned int, flags) 3803{ 3804 struct sched_attr attr; 3805 struct task_struct *p; 3806 int retval; 3807 3808 if (!uattr || pid < 0 || flags) 3809 return -EINVAL; 3810 3811 retval = sched_copy_attr(uattr, &attr); 3812 if (retval) 3813 return retval; 3814 3815 if ((int)attr.sched_policy < 0) 3816 return -EINVAL; 3817 3818 rcu_read_lock(); 3819 retval = -ESRCH; 3820 p = find_process_by_pid(pid); 3821 if (p != NULL) 3822 retval = sched_setattr(p, &attr); 3823 rcu_read_unlock(); 3824 3825 return retval; 3826} 3827 3828/** 3829 * sys_sched_getscheduler - get the policy (scheduling class) of a thread 3830 * @pid: the pid in question. 3831 * 3832 * Return: On success, the policy of the thread. Otherwise, a negative error 3833 * code. 3834 */ 3835SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid) 3836{ 3837 struct task_struct *p; 3838 int retval; 3839 3840 if (pid < 0) 3841 return -EINVAL; 3842 3843 retval = -ESRCH; 3844 rcu_read_lock(); 3845 p = find_process_by_pid(pid); 3846 if (p) { 3847 retval = security_task_getscheduler(p); 3848 if (!retval) 3849 retval = p->policy 3850 | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0); 3851 } 3852 rcu_read_unlock(); 3853 return retval; 3854} 3855 3856/** 3857 * sys_sched_getparam - get the RT priority of a thread 3858 * @pid: the pid in question. 3859 * @param: structure containing the RT priority. 3860 * 3861 * Return: On success, 0 and the RT priority is in @param. Otherwise, an error 3862 * code. 3863 */ 3864SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param) 3865{ 3866 struct sched_param lp = { .sched_priority = 0 }; 3867 struct task_struct *p; 3868 int retval; 3869 3870 if (!param || pid < 0) 3871 return -EINVAL; 3872 3873 rcu_read_lock(); 3874 p = find_process_by_pid(pid); 3875 retval = -ESRCH; 3876 if (!p) 3877 goto out_unlock; 3878 3879 retval = security_task_getscheduler(p); 3880 if (retval) 3881 goto out_unlock; 3882 3883 if (task_has_rt_policy(p)) 3884 lp.sched_priority = p->rt_priority; 3885 rcu_read_unlock(); 3886 3887 /* 3888 * This one might sleep, we cannot do it with a spinlock held ... 3889 */ 3890 retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; 3891 3892 return retval; 3893 3894out_unlock: 3895 rcu_read_unlock(); 3896 return retval; 3897} 3898 3899static int sched_read_attr(struct sched_attr __user *uattr, 3900 struct sched_attr *attr, 3901 unsigned int usize) 3902{ 3903 int ret; 3904 3905 if (!access_ok(VERIFY_WRITE, uattr, usize)) 3906 return -EFAULT; 3907 3908 /* 3909 * If we're handed a smaller struct than we know of, 3910 * ensure all the unknown bits are 0 - i.e. old 3911 * user-space does not get uncomplete information. 3912 */ 3913 if (usize < sizeof(*attr)) { 3914 unsigned char *addr; 3915 unsigned char *end; 3916 3917 addr = (void *)attr + usize; 3918 end = (void *)attr + sizeof(*attr); 3919 3920 for (; addr < end; addr++) { 3921 if (*addr) 3922 return -EFBIG; 3923 } 3924 3925 attr->size = usize; 3926 } 3927 3928 ret = copy_to_user(uattr, attr, attr->size); 3929 if (ret) 3930 return -EFAULT; 3931 3932 return 0; 3933} 3934 3935/** 3936 * sys_sched_getattr - similar to sched_getparam, but with sched_attr 3937 * @pid: the pid in question. 3938 * @uattr: structure containing the extended parameters. 3939 * @size: sizeof(attr) for fwd/bwd comp. 3940 * @flags: for future extension. 3941 */ 3942SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr, 3943 unsigned int, size, unsigned int, flags) 3944{ 3945 struct sched_attr attr = { 3946 .size = sizeof(struct sched_attr), 3947 }; 3948 struct task_struct *p; 3949 int retval; 3950 3951 if (!uattr || pid < 0 || size > PAGE_SIZE || 3952 size < SCHED_ATTR_SIZE_VER0 || flags) 3953 return -EINVAL; 3954 3955 rcu_read_lock(); 3956 p = find_process_by_pid(pid); 3957 retval = -ESRCH; 3958 if (!p) 3959 goto out_unlock; 3960 3961 retval = security_task_getscheduler(p); 3962 if (retval) 3963 goto out_unlock; 3964 3965 attr.sched_policy = p->policy; 3966 if (p->sched_reset_on_fork) 3967 attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK; 3968 if (task_has_dl_policy(p)) 3969 __getparam_dl(p, &attr); 3970 else if (task_has_rt_policy(p)) 3971 attr.sched_priority = p->rt_priority; 3972 else 3973 attr.sched_nice = task_nice(p); 3974 3975 rcu_read_unlock(); 3976 3977 retval = sched_read_attr(uattr, &attr, size); 3978 return retval; 3979 3980out_unlock: 3981 rcu_read_unlock(); 3982 return retval; 3983} 3984 3985long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) 3986{ 3987 cpumask_var_t cpus_allowed, new_mask; 3988 struct task_struct *p; 3989 int retval; 3990 3991 rcu_read_lock(); 3992 3993 p = find_process_by_pid(pid); 3994 if (!p) { 3995 rcu_read_unlock(); 3996 return -ESRCH; 3997 } 3998 3999 /* Prevent p going away */ 4000 get_task_struct(p); 4001 rcu_read_unlock(); 4002 4003 if (p->flags & PF_NO_SETAFFINITY) { 4004 retval = -EINVAL; 4005 goto out_put_task; 4006 } 4007 if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) { 4008 retval = -ENOMEM; 4009 goto out_put_task; 4010 } 4011 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) { 4012 retval = -ENOMEM; 4013 goto out_free_cpus_allowed; 4014 } 4015 retval = -EPERM; 4016 if (!check_same_owner(p)) { 4017 rcu_read_lock(); 4018 if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) { 4019 rcu_read_unlock(); 4020 goto out_unlock; 4021 } 4022 rcu_read_unlock(); 4023 } 4024 4025 retval = security_task_setscheduler(p); 4026 if (retval) 4027 goto out_unlock; 4028 4029 4030 cpuset_cpus_allowed(p, cpus_allowed); 4031 cpumask_and(new_mask, in_mask, cpus_allowed); 4032 4033 /* 4034 * Since bandwidth control happens on root_domain basis, 4035 * if admission test is enabled, we only admit -deadline 4036 * tasks allowed to run on all the CPUs in the task's 4037 * root_domain. 4038 */ 4039#ifdef CONFIG_SMP 4040 if (task_has_dl_policy(p)) { 4041 const struct cpumask *span = task_rq(p)->rd->span; 4042 4043 if (dl_bandwidth_enabled() && !cpumask_subset(span, new_mask)) { 4044 retval = -EBUSY; 4045 goto out_unlock; 4046 } 4047 } 4048#endif 4049again: 4050 retval = set_cpus_allowed_ptr(p, new_mask); 4051 4052 if (!retval) { 4053 cpuset_cpus_allowed(p, cpus_allowed); 4054 if (!cpumask_subset(new_mask, cpus_allowed)) { 4055 /* 4056 * We must have raced with a concurrent cpuset 4057 * update. Just reset the cpus_allowed to the 4058 * cpuset's cpus_allowed 4059 */ 4060 cpumask_copy(new_mask, cpus_allowed); 4061 goto again; 4062 } 4063 } 4064out_unlock: 4065 free_cpumask_var(new_mask); 4066out_free_cpus_allowed: 4067 free_cpumask_var(cpus_allowed); 4068out_put_task: 4069 put_task_struct(p); 4070 return retval; 4071} 4072 4073static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, 4074 struct cpumask *new_mask) 4075{ 4076 if (len < cpumask_size()) 4077 cpumask_clear(new_mask); 4078 else if (len > cpumask_size()) 4079 len = cpumask_size(); 4080 4081 return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; 4082} 4083 4084/** 4085 * sys_sched_setaffinity - set the cpu affinity of a process 4086 * @pid: pid of the process 4087 * @len: length in bytes of the bitmask pointed to by user_mask_ptr 4088 * @user_mask_ptr: user-space pointer to the new cpu mask 4089 * 4090 * Return: 0 on success. An error code otherwise. 4091 */ 4092SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len, 4093 unsigned long __user *, user_mask_ptr) 4094{ 4095 cpumask_var_t new_mask; 4096 int retval; 4097 4098 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) 4099 return -ENOMEM; 4100 4101 retval = get_user_cpu_mask(user_mask_ptr, len, new_mask); 4102 if (retval == 0) 4103 retval = sched_setaffinity(pid, new_mask); 4104 free_cpumask_var(new_mask); 4105 return retval; 4106} 4107 4108long sched_getaffinity(pid_t pid, struct cpumask *mask) 4109{ 4110 struct task_struct *p; 4111 unsigned long flags; 4112 int retval; 4113 4114 rcu_read_lock(); 4115 4116 retval = -ESRCH; 4117 p = find_process_by_pid(pid); 4118 if (!p) 4119 goto out_unlock; 4120 4121 retval = security_task_getscheduler(p); 4122 if (retval) 4123 goto out_unlock; 4124 4125 raw_spin_lock_irqsave(&p->pi_lock, flags); 4126 cpumask_and(mask, &p->cpus_allowed, cpu_active_mask); 4127 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 4128 4129out_unlock: 4130 rcu_read_unlock(); 4131 4132 return retval; 4133} 4134 4135/** 4136 * sys_sched_getaffinity - get the cpu affinity of a process 4137 * @pid: pid of the process 4138 * @len: length in bytes of the bitmask pointed to by user_mask_ptr 4139 * @user_mask_ptr: user-space pointer to hold the current cpu mask 4140 * 4141 * Return: 0 on success. An error code otherwise. 4142 */ 4143SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len, 4144 unsigned long __user *, user_mask_ptr) 4145{ 4146 int ret; 4147 cpumask_var_t mask; 4148 4149 if ((len * BITS_PER_BYTE) < nr_cpu_ids) 4150 return -EINVAL; 4151 if (len & (sizeof(unsigned long)-1)) 4152 return -EINVAL; 4153 4154 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) 4155 return -ENOMEM; 4156 4157 ret = sched_getaffinity(pid, mask); 4158 if (ret == 0) { 4159 size_t retlen = min_t(size_t, len, cpumask_size()); 4160 4161 if (copy_to_user(user_mask_ptr, mask, retlen)) 4162 ret = -EFAULT; 4163 else 4164 ret = retlen; 4165 } 4166 free_cpumask_var(mask); 4167 4168 return ret; 4169} 4170 4171/** 4172 * sys_sched_yield - yield the current processor to other threads. 4173 * 4174 * This function yields the current CPU to other tasks. If there are no 4175 * other threads running on this CPU then this function will return. 4176 * 4177 * Return: 0. 4178 */ 4179SYSCALL_DEFINE0(sched_yield) 4180{ 4181 struct rq *rq = this_rq_lock(); 4182 4183 schedstat_inc(rq, yld_count); 4184 current->sched_class->yield_task(rq); 4185 4186 /* 4187 * Since we are going to call schedule() anyway, there's 4188 * no need to preempt or enable interrupts: 4189 */ 4190 __release(rq->lock); 4191 spin_release(&rq->lock.dep_map, 1, _THIS_IP_); 4192 do_raw_spin_unlock(&rq->lock); 4193 sched_preempt_enable_no_resched(); 4194 4195 schedule(); 4196 4197 return 0; 4198} 4199 4200static void __cond_resched(void) 4201{ 4202 __preempt_count_add(PREEMPT_ACTIVE); 4203 __schedule(); 4204 __preempt_count_sub(PREEMPT_ACTIVE); 4205} 4206 4207int __sched _cond_resched(void) 4208{ 4209 if (should_resched()) { 4210 __cond_resched(); 4211 return 1; 4212 } 4213 return 0; 4214} 4215EXPORT_SYMBOL(_cond_resched); 4216 4217/* 4218 * __cond_resched_lock() - if a reschedule is pending, drop the given lock, 4219 * call schedule, and on return reacquire the lock. 4220 * 4221 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level 4222 * operations here to prevent schedule() from being called twice (once via 4223 * spin_unlock(), once by hand). 4224 */ 4225int __cond_resched_lock(spinlock_t *lock) 4226{ 4227 int resched = should_resched(); 4228 int ret = 0; 4229 4230 lockdep_assert_held(lock); 4231 4232 if (spin_needbreak(lock) || resched) { 4233 spin_unlock(lock); 4234 if (resched) 4235 __cond_resched(); 4236 else 4237 cpu_relax(); 4238 ret = 1; 4239 spin_lock(lock); 4240 } 4241 return ret; 4242} 4243EXPORT_SYMBOL(__cond_resched_lock); 4244 4245int __sched __cond_resched_softirq(void) 4246{ 4247 BUG_ON(!in_softirq()); 4248 4249 if (should_resched()) { 4250 local_bh_enable(); 4251 __cond_resched(); 4252 local_bh_disable(); 4253 return 1; 4254 } 4255 return 0; 4256} 4257EXPORT_SYMBOL(__cond_resched_softirq); 4258 4259/** 4260 * yield - yield the current processor to other threads. 4261 * 4262 * Do not ever use this function, there's a 99% chance you're doing it wrong. 4263 * 4264 * The scheduler is at all times free to pick the calling task as the most 4265 * eligible task to run, if removing the yield() call from your code breaks 4266 * it, its already broken. 4267 * 4268 * Typical broken usage is: 4269 * 4270 * while (!event) 4271 * yield(); 4272 * 4273 * where one assumes that yield() will let 'the other' process run that will 4274 * make event true. If the current task is a SCHED_FIFO task that will never 4275 * happen. Never use yield() as a progress guarantee!! 4276 * 4277 * If you want to use yield() to wait for something, use wait_event(). 4278 * If you want to use yield() to be 'nice' for others, use cond_resched(). 4279 * If you still want to use yield(), do not! 4280 */ 4281void __sched yield(void) 4282{ 4283 set_current_state(TASK_RUNNING); 4284 sys_sched_yield(); 4285} 4286EXPORT_SYMBOL(yield); 4287 4288/** 4289 * yield_to - yield the current processor to another thread in 4290 * your thread group, or accelerate that thread toward the 4291 * processor it's on. 4292 * @p: target task 4293 * @preempt: whether task preemption is allowed or not 4294 * 4295 * It's the caller's job to ensure that the target task struct 4296 * can't go away on us before we can do any checks. 4297 * 4298 * Return: 4299 * true (>0) if we indeed boosted the target task. 4300 * false (0) if we failed to boost the target. 4301 * -ESRCH if there's no task to yield to. 4302 */ 4303int __sched yield_to(struct task_struct *p, bool preempt) 4304{ 4305 struct task_struct *curr = current; 4306 struct rq *rq, *p_rq; 4307 unsigned long flags; 4308 int yielded = 0; 4309 4310 local_irq_save(flags); 4311 rq = this_rq(); 4312 4313again: 4314 p_rq = task_rq(p); 4315 /* 4316 * If we're the only runnable task on the rq and target rq also 4317 * has only one task, there's absolutely no point in yielding. 4318 */ 4319 if (rq->nr_running == 1 && p_rq->nr_running == 1) { 4320 yielded = -ESRCH; 4321 goto out_irq; 4322 } 4323 4324 double_rq_lock(rq, p_rq); 4325 if (task_rq(p) != p_rq) { 4326 double_rq_unlock(rq, p_rq); 4327 goto again; 4328 } 4329 4330 if (!curr->sched_class->yield_to_task) 4331 goto out_unlock; 4332 4333 if (curr->sched_class != p->sched_class) 4334 goto out_unlock; 4335 4336 if (task_running(p_rq, p) || p->state) 4337 goto out_unlock; 4338 4339 yielded = curr->sched_class->yield_to_task(rq, p, preempt); 4340 if (yielded) { 4341 schedstat_inc(rq, yld_count); 4342 /* 4343 * Make p's CPU reschedule; pick_next_entity takes care of 4344 * fairness. 4345 */ 4346 if (preempt && rq != p_rq) 4347 resched_curr(p_rq); 4348 } 4349 4350out_unlock: 4351 double_rq_unlock(rq, p_rq); 4352out_irq: 4353 local_irq_restore(flags); 4354 4355 if (yielded > 0) 4356 schedule(); 4357 4358 return yielded; 4359} 4360EXPORT_SYMBOL_GPL(yield_to); 4361 4362/* 4363 * This task is about to go to sleep on IO. Increment rq->nr_iowait so 4364 * that process accounting knows that this is a task in IO wait state. 4365 */ 4366void __sched io_schedule(void) 4367{ 4368 struct rq *rq = raw_rq(); 4369 4370 delayacct_blkio_start(); 4371 atomic_inc(&rq->nr_iowait); 4372 blk_flush_plug(current); 4373 current->in_iowait = 1; 4374 schedule(); 4375 current->in_iowait = 0; 4376 atomic_dec(&rq->nr_iowait); 4377 delayacct_blkio_end(); 4378} 4379EXPORT_SYMBOL(io_schedule); 4380 4381long __sched io_schedule_timeout(long timeout) 4382{ 4383 struct rq *rq = raw_rq(); 4384 long ret; 4385 4386 delayacct_blkio_start(); 4387 atomic_inc(&rq->nr_iowait); 4388 blk_flush_plug(current); 4389 current->in_iowait = 1; 4390 ret = schedule_timeout(timeout); 4391 current->in_iowait = 0; 4392 atomic_dec(&rq->nr_iowait); 4393 delayacct_blkio_end(); 4394 return ret; 4395} 4396 4397/** 4398 * sys_sched_get_priority_max - return maximum RT priority. 4399 * @policy: scheduling class. 4400 * 4401 * Return: On success, this syscall returns the maximum 4402 * rt_priority that can be used by a given scheduling class. 4403 * On failure, a negative error code is returned. 4404 */ 4405SYSCALL_DEFINE1(sched_get_priority_max, int, policy) 4406{ 4407 int ret = -EINVAL; 4408 4409 switch (policy) { 4410 case SCHED_FIFO: 4411 case SCHED_RR: 4412 ret = MAX_USER_RT_PRIO-1; 4413 break; 4414 case SCHED_DEADLINE: 4415 case SCHED_NORMAL: 4416 case SCHED_BATCH: 4417 case SCHED_IDLE: 4418 ret = 0; 4419 break; 4420 } 4421 return ret; 4422} 4423 4424/** 4425 * sys_sched_get_priority_min - return minimum RT priority. 4426 * @policy: scheduling class. 4427 * 4428 * Return: On success, this syscall returns the minimum 4429 * rt_priority that can be used by a given scheduling class. 4430 * On failure, a negative error code is returned. 4431 */ 4432SYSCALL_DEFINE1(sched_get_priority_min, int, policy) 4433{ 4434 int ret = -EINVAL; 4435 4436 switch (policy) { 4437 case SCHED_FIFO: 4438 case SCHED_RR: 4439 ret = 1; 4440 break; 4441 case SCHED_DEADLINE: 4442 case SCHED_NORMAL: 4443 case SCHED_BATCH: 4444 case SCHED_IDLE: 4445 ret = 0; 4446 } 4447 return ret; 4448} 4449 4450/** 4451 * sys_sched_rr_get_interval - return the default timeslice of a process. 4452 * @pid: pid of the process. 4453 * @interval: userspace pointer to the timeslice value. 4454 * 4455 * this syscall writes the default timeslice value of a given process 4456 * into the user-space timespec buffer. A value of '0' means infinity. 4457 * 4458 * Return: On success, 0 and the timeslice is in @interval. Otherwise, 4459 * an error code. 4460 */ 4461SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid, 4462 struct timespec __user *, interval) 4463{ 4464 struct task_struct *p; 4465 unsigned int time_slice; 4466 unsigned long flags; 4467 struct rq *rq; 4468 int retval; 4469 struct timespec t; 4470 4471 if (pid < 0) 4472 return -EINVAL; 4473 4474 retval = -ESRCH; 4475 rcu_read_lock(); 4476 p = find_process_by_pid(pid); 4477 if (!p) 4478 goto out_unlock; 4479 4480 retval = security_task_getscheduler(p); 4481 if (retval) 4482 goto out_unlock; 4483 4484 rq = task_rq_lock(p, &flags); 4485 time_slice = 0; 4486 if (p->sched_class->get_rr_interval) 4487 time_slice = p->sched_class->get_rr_interval(rq, p); 4488 task_rq_unlock(rq, p, &flags); 4489 4490 rcu_read_unlock(); 4491 jiffies_to_timespec(time_slice, &t); 4492 retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; 4493 return retval; 4494 4495out_unlock: 4496 rcu_read_unlock(); 4497 return retval; 4498} 4499 4500static const char stat_nam[] = TASK_STATE_TO_CHAR_STR; 4501 4502void sched_show_task(struct task_struct *p) 4503{ 4504 unsigned long free = 0; 4505 int ppid; 4506 unsigned state; 4507 4508 state = p->state ? __ffs(p->state) + 1 : 0; 4509 printk(KERN_INFO "%-15.15s %c", p->comm, 4510 state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); 4511#if BITS_PER_LONG == 32 4512 if (state == TASK_RUNNING) 4513 printk(KERN_CONT " running "); 4514 else 4515 printk(KERN_CONT " %08lx ", thread_saved_pc(p)); 4516#else 4517 if (state == TASK_RUNNING) 4518 printk(KERN_CONT " running task "); 4519 else 4520 printk(KERN_CONT " %016lx ", thread_saved_pc(p)); 4521#endif 4522#ifdef CONFIG_DEBUG_STACK_USAGE 4523 free = stack_not_used(p); 4524#endif 4525 rcu_read_lock(); 4526 ppid = task_pid_nr(rcu_dereference(p->real_parent)); 4527 rcu_read_unlock(); 4528 printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free, 4529 task_pid_nr(p), ppid, 4530 (unsigned long)task_thread_info(p)->flags); 4531 4532 print_worker_info(KERN_INFO, p); 4533 show_stack(p, NULL); 4534} 4535 4536void show_state_filter(unsigned long state_filter) 4537{ 4538 struct task_struct *g, *p; 4539 4540#if BITS_PER_LONG == 32 4541 printk(KERN_INFO 4542 " task PC stack pid father\n"); 4543#else 4544 printk(KERN_INFO 4545 " task PC stack pid father\n"); 4546#endif 4547 rcu_read_lock(); 4548 for_each_process_thread(g, p) { 4549 /* 4550 * reset the NMI-timeout, listing all files on a slow 4551 * console might take a lot of time: 4552 */ 4553 touch_nmi_watchdog(); 4554 if (!state_filter || (p->state & state_filter)) 4555 sched_show_task(p); 4556 } 4557 4558 touch_all_softlockup_watchdogs(); 4559 4560#ifdef CONFIG_SCHED_DEBUG 4561 sysrq_sched_debug_show(); 4562#endif 4563 rcu_read_unlock(); 4564 /* 4565 * Only show locks if all tasks are dumped: 4566 */ 4567 if (!state_filter) 4568 debug_show_all_locks(); 4569} 4570 4571void init_idle_bootup_task(struct task_struct *idle) 4572{ 4573 idle->sched_class = &idle_sched_class; 4574} 4575 4576/** 4577 * init_idle - set up an idle thread for a given CPU 4578 * @idle: task in question 4579 * @cpu: cpu the idle task belongs to 4580 * 4581 * NOTE: this function does not set the idle thread's NEED_RESCHED 4582 * flag, to make booting more robust. 4583 */ 4584void init_idle(struct task_struct *idle, int cpu) 4585{ 4586 struct rq *rq = cpu_rq(cpu); 4587 unsigned long flags; 4588 4589 raw_spin_lock_irqsave(&rq->lock, flags); 4590 4591 __sched_fork(0, idle); 4592 idle->state = TASK_RUNNING; 4593 idle->se.exec_start = sched_clock(); 4594 4595 do_set_cpus_allowed(idle, cpumask_of(cpu)); 4596 /* 4597 * We're having a chicken and egg problem, even though we are 4598 * holding rq->lock, the cpu isn't yet set to this cpu so the 4599 * lockdep check in task_group() will fail. 4600 * 4601 * Similar case to sched_fork(). / Alternatively we could 4602 * use task_rq_lock() here and obtain the other rq->lock. 4603 * 4604 * Silence PROVE_RCU 4605 */ 4606 rcu_read_lock(); 4607 __set_task_cpu(idle, cpu); 4608 rcu_read_unlock(); 4609 4610 rq->curr = rq->idle = idle; 4611 idle->on_rq = TASK_ON_RQ_QUEUED; 4612#if defined(CONFIG_SMP) 4613 idle->on_cpu = 1; 4614#endif 4615 raw_spin_unlock_irqrestore(&rq->lock, flags); 4616 4617 /* Set the preempt count _outside_ the spinlocks! */ 4618 init_idle_preempt_count(idle, cpu); 4619 4620 /* 4621 * The idle tasks have their own, simple scheduling class: 4622 */ 4623 idle->sched_class = &idle_sched_class; 4624 ftrace_graph_init_idle_task(idle, cpu); 4625 vtime_init_idle(idle, cpu); 4626#if defined(CONFIG_SMP) 4627 sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu); 4628#endif 4629} 4630 4631#ifdef CONFIG_SMP 4632/* 4633 * move_queued_task - move a queued task to new rq. 4634 * 4635 * Returns (locked) new rq. Old rq's lock is released. 4636 */ 4637static struct rq *move_queued_task(struct task_struct *p, int new_cpu) 4638{ 4639 struct rq *rq = task_rq(p); 4640 4641 lockdep_assert_held(&rq->lock); 4642 4643 dequeue_task(rq, p, 0); 4644 p->on_rq = TASK_ON_RQ_MIGRATING; 4645 set_task_cpu(p, new_cpu); 4646 raw_spin_unlock(&rq->lock); 4647 4648 rq = cpu_rq(new_cpu); 4649 4650 raw_spin_lock(&rq->lock); 4651 BUG_ON(task_cpu(p) != new_cpu); 4652 p->on_rq = TASK_ON_RQ_QUEUED; 4653 enqueue_task(rq, p, 0); 4654 check_preempt_curr(rq, p, 0); 4655 4656 return rq; 4657} 4658 4659void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) 4660{ 4661 if (p->sched_class && p->sched_class->set_cpus_allowed) 4662 p->sched_class->set_cpus_allowed(p, new_mask); 4663 4664 cpumask_copy(&p->cpus_allowed, new_mask); 4665 p->nr_cpus_allowed = cpumask_weight(new_mask); 4666} 4667 4668/* 4669 * This is how migration works: 4670 * 4671 * 1) we invoke migration_cpu_stop() on the target CPU using 4672 * stop_one_cpu(). 4673 * 2) stopper starts to run (implicitly forcing the migrated thread 4674 * off the CPU) 4675 * 3) it checks whether the migrated task is still in the wrong runqueue. 4676 * 4) if it's in the wrong runqueue then the migration thread removes 4677 * it and puts it into the right queue. 4678 * 5) stopper completes and stop_one_cpu() returns and the migration 4679 * is done. 4680 */ 4681 4682/* 4683 * Change a given task's CPU affinity. Migrate the thread to a 4684 * proper CPU and schedule it away if the CPU it's executing on 4685 * is removed from the allowed bitmask. 4686 * 4687 * NOTE: the caller must have a valid reference to the task, the 4688 * task must not exit() & deallocate itself prematurely. The 4689 * call is not atomic; no spinlocks may be held. 4690 */ 4691int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) 4692{ 4693 unsigned long flags; 4694 struct rq *rq; 4695 unsigned int dest_cpu; 4696 int ret = 0; 4697 4698 rq = task_rq_lock(p, &flags); 4699 4700 if (cpumask_equal(&p->cpus_allowed, new_mask)) 4701 goto out; 4702 4703 if (!cpumask_intersects(new_mask, cpu_active_mask)) { 4704 ret = -EINVAL; 4705 goto out; 4706 } 4707 4708 do_set_cpus_allowed(p, new_mask); 4709 4710 /* Can the task run on the task's current CPU? If so, we're done */ 4711 if (cpumask_test_cpu(task_cpu(p), new_mask)) 4712 goto out; 4713 4714 dest_cpu = cpumask_any_and(cpu_active_mask, new_mask); 4715 if (task_running(rq, p) || p->state == TASK_WAKING) { 4716 struct migration_arg arg = { p, dest_cpu }; 4717 /* Need help from migration thread: drop lock and wait. */ 4718 task_rq_unlock(rq, p, &flags); 4719 stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg); 4720 tlb_migrate_finish(p->mm); 4721 return 0; 4722 } else if (task_on_rq_queued(p)) 4723 rq = move_queued_task(p, dest_cpu); 4724out: 4725 task_rq_unlock(rq, p, &flags); 4726 4727 return ret; 4728} 4729EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr); 4730 4731/* 4732 * Move (not current) task off this cpu, onto dest cpu. We're doing 4733 * this because either it can't run here any more (set_cpus_allowed() 4734 * away from this CPU, or CPU going down), or because we're 4735 * attempting to rebalance this task on exec (sched_exec). 4736 * 4737 * So we race with normal scheduler movements, but that's OK, as long 4738 * as the task is no longer on this CPU. 4739 * 4740 * Returns non-zero if task was successfully migrated. 4741 */ 4742static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) 4743{ 4744 struct rq *rq; 4745 int ret = 0; 4746 4747 if (unlikely(!cpu_active(dest_cpu))) 4748 return ret; 4749 4750 rq = cpu_rq(src_cpu); 4751 4752 raw_spin_lock(&p->pi_lock); 4753 raw_spin_lock(&rq->lock); 4754 /* Already moved. */ 4755 if (task_cpu(p) != src_cpu) 4756 goto done; 4757 4758 /* Affinity changed (again). */ 4759 if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) 4760 goto fail; 4761 4762 /* 4763 * If we're not on a rq, the next wake-up will ensure we're 4764 * placed properly. 4765 */ 4766 if (task_on_rq_queued(p)) 4767 rq = move_queued_task(p, dest_cpu); 4768done: 4769 ret = 1; 4770fail: 4771 raw_spin_unlock(&rq->lock); 4772 raw_spin_unlock(&p->pi_lock); 4773 return ret; 4774} 4775 4776#ifdef CONFIG_NUMA_BALANCING 4777/* Migrate current task p to target_cpu */ 4778int migrate_task_to(struct task_struct *p, int target_cpu) 4779{ 4780 struct migration_arg arg = { p, target_cpu }; 4781 int curr_cpu = task_cpu(p); 4782 4783 if (curr_cpu == target_cpu) 4784 return 0; 4785 4786 if (!cpumask_test_cpu(target_cpu, tsk_cpus_allowed(p))) 4787 return -EINVAL; 4788 4789 /* TODO: This is not properly updating schedstats */ 4790 4791 trace_sched_move_numa(p, curr_cpu, target_cpu); 4792 return stop_one_cpu(curr_cpu, migration_cpu_stop, &arg); 4793} 4794 4795/* 4796 * Requeue a task on a given node and accurately track the number of NUMA 4797 * tasks on the runqueues 4798 */ 4799void sched_setnuma(struct task_struct *p, int nid) 4800{ 4801 struct rq *rq; 4802 unsigned long flags; 4803 bool queued, running; 4804 4805 rq = task_rq_lock(p, &flags); 4806 queued = task_on_rq_queued(p); 4807 running = task_current(rq, p); 4808 4809 if (queued) 4810 dequeue_task(rq, p, 0); 4811 if (running) 4812 put_prev_task(rq, p); 4813 4814 p->numa_preferred_nid = nid; 4815 4816 if (running) 4817 p->sched_class->set_curr_task(rq); 4818 if (queued) 4819 enqueue_task(rq, p, 0); 4820 task_rq_unlock(rq, p, &flags); 4821} 4822#endif 4823 4824/* 4825 * migration_cpu_stop - this will be executed by a highprio stopper thread 4826 * and performs thread migration by bumping thread off CPU then 4827 * 'pushing' onto another runqueue. 4828 */ 4829static int migration_cpu_stop(void *data) 4830{ 4831 struct migration_arg *arg = data; 4832 4833 /* 4834 * The original target cpu might have gone down and we might 4835 * be on another cpu but it doesn't matter. 4836 */ 4837 local_irq_disable(); 4838 /* 4839 * We need to explicitly wake pending tasks before running 4840 * __migrate_task() such that we will not miss enforcing cpus_allowed 4841 * during wakeups, see set_cpus_allowed_ptr()'s TASK_WAKING test. 4842 */ 4843 sched_ttwu_pending(); 4844 __migrate_task(arg->task, raw_smp_processor_id(), arg->dest_cpu); 4845 local_irq_enable(); 4846 return 0; 4847} 4848 4849#ifdef CONFIG_HOTPLUG_CPU 4850 4851/* 4852 * Ensures that the idle task is using init_mm right before its cpu goes 4853 * offline. 4854 */ 4855void idle_task_exit(void) 4856{ 4857 struct mm_struct *mm = current->active_mm; 4858 4859 BUG_ON(cpu_online(smp_processor_id())); 4860 4861 if (mm != &init_mm) { 4862 switch_mm(mm, &init_mm, current); 4863 finish_arch_post_lock_switch(); 4864 } 4865 mmdrop(mm); 4866} 4867 4868/* 4869 * Since this CPU is going 'away' for a while, fold any nr_active delta 4870 * we might have. Assumes we're called after migrate_tasks() so that the 4871 * nr_active count is stable. 4872 * 4873 * Also see the comment "Global load-average calculations". 4874 */ 4875static void calc_load_migrate(struct rq *rq) 4876{ 4877 long delta = calc_load_fold_active(rq); 4878 if (delta) 4879 atomic_long_add(delta, &calc_load_tasks); 4880} 4881 4882static void put_prev_task_fake(struct rq *rq, struct task_struct *prev) 4883{ 4884} 4885 4886static const struct sched_class fake_sched_class = { 4887 .put_prev_task = put_prev_task_fake, 4888}; 4889 4890static struct task_struct fake_task = { 4891 /* 4892 * Avoid pull_{rt,dl}_task() 4893 */ 4894 .prio = MAX_PRIO + 1, 4895 .sched_class = &fake_sched_class, 4896}; 4897 4898/* 4899 * Migrate all tasks from the rq, sleeping tasks will be migrated by 4900 * try_to_wake_up()->select_task_rq(). 4901 * 4902 * Called with rq->lock held even though we'er in stop_machine() and 4903 * there's no concurrency possible, we hold the required locks anyway 4904 * because of lock validation efforts. 4905 */ 4906static void migrate_tasks(unsigned int dead_cpu) 4907{ 4908 struct rq *rq = cpu_rq(dead_cpu); 4909 struct task_struct *next, *stop = rq->stop; 4910 int dest_cpu; 4911 4912 /* 4913 * Fudge the rq selection such that the below task selection loop 4914 * doesn't get stuck on the currently eligible stop task. 4915 * 4916 * We're currently inside stop_machine() and the rq is either stuck 4917 * in the stop_machine_cpu_stop() loop, or we're executing this code, 4918 * either way we should never end up calling schedule() until we're 4919 * done here. 4920 */ 4921 rq->stop = NULL; 4922 4923 /* 4924 * put_prev_task() and pick_next_task() sched 4925 * class method both need to have an up-to-date 4926 * value of rq->clock[_task] 4927 */ 4928 update_rq_clock(rq); 4929 4930 for ( ; ; ) { 4931 /* 4932 * There's this thread running, bail when that's the only 4933 * remaining thread. 4934 */ 4935 if (rq->nr_running == 1) 4936 break; 4937 4938 next = pick_next_task(rq, &fake_task); 4939 BUG_ON(!next); 4940 next->sched_class->put_prev_task(rq, next); 4941 4942 /* Find suitable destination for @next, with force if needed. */ 4943 dest_cpu = select_fallback_rq(dead_cpu, next); 4944 raw_spin_unlock(&rq->lock); 4945 4946 __migrate_task(next, dead_cpu, dest_cpu); 4947 4948 raw_spin_lock(&rq->lock); 4949 } 4950 4951 rq->stop = stop; 4952} 4953 4954#endif /* CONFIG_HOTPLUG_CPU */ 4955 4956#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL) 4957 4958static struct ctl_table sd_ctl_dir[] = { 4959 { 4960 .procname = "sched_domain", 4961 .mode = 0555, 4962 }, 4963 {} 4964}; 4965 4966static struct ctl_table sd_ctl_root[] = { 4967 { 4968 .procname = "kernel", 4969 .mode = 0555, 4970 .child = sd_ctl_dir, 4971 }, 4972 {} 4973}; 4974 4975static struct ctl_table *sd_alloc_ctl_entry(int n) 4976{ 4977 struct ctl_table *entry = 4978 kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL); 4979 4980 return entry; 4981} 4982 4983static void sd_free_ctl_entry(struct ctl_table **tablep) 4984{ 4985 struct ctl_table *entry; 4986 4987 /* 4988 * In the intermediate directories, both the child directory and 4989 * procname are dynamically allocated and could fail but the mode 4990 * will always be set. In the lowest directory the names are 4991 * static strings and all have proc handlers. 4992 */ 4993 for (entry = *tablep; entry->mode; entry++) { 4994 if (entry->child) 4995 sd_free_ctl_entry(&entry->child); 4996 if (entry->proc_handler == NULL) 4997 kfree(entry->procname); 4998 } 4999 5000 kfree(*tablep); 5001 *tablep = NULL; 5002} 5003 5004static int min_load_idx = 0; 5005static int max_load_idx = CPU_LOAD_IDX_MAX-1; 5006 5007static void 5008set_table_entry(struct ctl_table *entry, 5009 const char *procname, void *data, int maxlen, 5010 umode_t mode, proc_handler *proc_handler, 5011 bool load_idx) 5012{ 5013 entry->procname = procname; 5014 entry->data = data; 5015 entry->maxlen = maxlen; 5016 entry->mode = mode; 5017 entry->proc_handler = proc_handler; 5018 5019 if (load_idx) { 5020 entry->extra1 = &min_load_idx; 5021 entry->extra2 = &max_load_idx; 5022 } 5023} 5024 5025static struct ctl_table * 5026sd_alloc_ctl_domain_table(struct sched_domain *sd) 5027{ 5028 struct ctl_table *table = sd_alloc_ctl_entry(14); 5029 5030 if (table == NULL) 5031 return NULL; 5032 5033 set_table_entry(&table[0], "min_interval", &sd->min_interval, 5034 sizeof(long), 0644, proc_doulongvec_minmax, false); 5035 set_table_entry(&table[1], "max_interval", &sd->max_interval, 5036 sizeof(long), 0644, proc_doulongvec_minmax, false); 5037 set_table_entry(&table[2], "busy_idx", &sd->busy_idx, 5038 sizeof(int), 0644, proc_dointvec_minmax, true); 5039 set_table_entry(&table[3], "idle_idx", &sd->idle_idx, 5040 sizeof(int), 0644, proc_dointvec_minmax, true); 5041 set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx, 5042 sizeof(int), 0644, proc_dointvec_minmax, true); 5043 set_table_entry(&table[5], "wake_idx", &sd->wake_idx, 5044 sizeof(int), 0644, proc_dointvec_minmax, true); 5045 set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx, 5046 sizeof(int), 0644, proc_dointvec_minmax, true); 5047 set_table_entry(&table[7], "busy_factor", &sd->busy_factor, 5048 sizeof(int), 0644, proc_dointvec_minmax, false); 5049 set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct, 5050 sizeof(int), 0644, proc_dointvec_minmax, false); 5051 set_table_entry(&table[9], "cache_nice_tries", 5052 &sd->cache_nice_tries, 5053 sizeof(int), 0644, proc_dointvec_minmax, false); 5054 set_table_entry(&table[10], "flags", &sd->flags, 5055 sizeof(int), 0644, proc_dointvec_minmax, false); 5056 set_table_entry(&table[11], "max_newidle_lb_cost", 5057 &sd->max_newidle_lb_cost, 5058 sizeof(long), 0644, proc_doulongvec_minmax, false); 5059 set_table_entry(&table[12], "name", sd->name, 5060 CORENAME_MAX_SIZE, 0444, proc_dostring, false); 5061 /* &table[13] is terminator */ 5062 5063 return table; 5064} 5065 5066static struct ctl_table *sd_alloc_ctl_cpu_table(int cpu) 5067{ 5068 struct ctl_table *entry, *table; 5069 struct sched_domain *sd; 5070 int domain_num = 0, i; 5071 char buf[32]; 5072 5073 for_each_domain(cpu, sd) 5074 domain_num++; 5075 entry = table = sd_alloc_ctl_entry(domain_num + 1); 5076 if (table == NULL) 5077 return NULL; 5078 5079 i = 0; 5080 for_each_domain(cpu, sd) { 5081 snprintf(buf, 32, "domain%d", i); 5082 entry->procname = kstrdup(buf, GFP_KERNEL); 5083 entry->mode = 0555; 5084 entry->child = sd_alloc_ctl_domain_table(sd); 5085 entry++; 5086 i++; 5087 } 5088 return table; 5089} 5090 5091static struct ctl_table_header *sd_sysctl_header; 5092static void register_sched_domain_sysctl(void) 5093{ 5094 int i, cpu_num = num_possible_cpus(); 5095 struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1); 5096 char buf[32]; 5097 5098 WARN_ON(sd_ctl_dir[0].child); 5099 sd_ctl_dir[0].child = entry; 5100 5101 if (entry == NULL) 5102 return; 5103 5104 for_each_possible_cpu(i) { 5105 snprintf(buf, 32, "cpu%d", i); 5106 entry->procname = kstrdup(buf, GFP_KERNEL); 5107 entry->mode = 0555; 5108 entry->child = sd_alloc_ctl_cpu_table(i); 5109 entry++; 5110 } 5111 5112 WARN_ON(sd_sysctl_header); 5113 sd_sysctl_header = register_sysctl_table(sd_ctl_root); 5114} 5115 5116/* may be called multiple times per register */ 5117static void unregister_sched_domain_sysctl(void) 5118{ 5119 if (sd_sysctl_header) 5120 unregister_sysctl_table(sd_sysctl_header); 5121 sd_sysctl_header = NULL; 5122 if (sd_ctl_dir[0].child) 5123 sd_free_ctl_entry(&sd_ctl_dir[0].child); 5124} 5125#else 5126static void register_sched_domain_sysctl(void) 5127{ 5128} 5129static void unregister_sched_domain_sysctl(void) 5130{ 5131} 5132#endif 5133 5134static void set_rq_online(struct rq *rq) 5135{ 5136 if (!rq->online) { 5137 const struct sched_class *class; 5138 5139 cpumask_set_cpu(rq->cpu, rq->rd->online); 5140 rq->online = 1; 5141 5142 for_each_class(class) { 5143 if (class->rq_online) 5144 class->rq_online(rq); 5145 } 5146 } 5147} 5148 5149static void set_rq_offline(struct rq *rq) 5150{ 5151 if (rq->online) { 5152 const struct sched_class *class; 5153 5154 for_each_class(class) { 5155 if (class->rq_offline) 5156 class->rq_offline(rq); 5157 } 5158 5159 cpumask_clear_cpu(rq->cpu, rq->rd->online); 5160 rq->online = 0; 5161 } 5162} 5163 5164/* 5165 * migration_call - callback that gets triggered when a CPU is added. 5166 * Here we can start up the necessary migration thread for the new CPU. 5167 */ 5168static int 5169migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) 5170{ 5171 int cpu = (long)hcpu; 5172 unsigned long flags; 5173 struct rq *rq = cpu_rq(cpu); 5174 5175 switch (action & ~CPU_TASKS_FROZEN) { 5176 5177 case CPU_UP_PREPARE: 5178 rq->calc_load_update = calc_load_update; 5179 break; 5180 5181 case CPU_ONLINE: 5182 /* Update our root-domain */ 5183 raw_spin_lock_irqsave(&rq->lock, flags); 5184 if (rq->rd) { 5185 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); 5186 5187 set_rq_online(rq); 5188 } 5189 raw_spin_unlock_irqrestore(&rq->lock, flags); 5190 break; 5191 5192#ifdef CONFIG_HOTPLUG_CPU 5193 case CPU_DYING: 5194 sched_ttwu_pending(); 5195 /* Update our root-domain */ 5196 raw_spin_lock_irqsave(&rq->lock, flags); 5197 if (rq->rd) { 5198 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); 5199 set_rq_offline(rq); 5200 } 5201 migrate_tasks(cpu); 5202 BUG_ON(rq->nr_running != 1); /* the migration thread */ 5203 raw_spin_unlock_irqrestore(&rq->lock, flags); 5204 break; 5205 5206 case CPU_DEAD: 5207 calc_load_migrate(rq); 5208 break; 5209#endif 5210 } 5211 5212 update_max_interval(); 5213 5214 return NOTIFY_OK; 5215} 5216 5217/* 5218 * Register at high priority so that task migration (migrate_all_tasks) 5219 * happens before everything else. This has to be lower priority than 5220 * the notifier in the perf_event subsystem, though. 5221 */ 5222static struct notifier_block migration_notifier = { 5223 .notifier_call = migration_call, 5224 .priority = CPU_PRI_MIGRATION, 5225}; 5226 5227static void __cpuinit set_cpu_rq_start_time(void) 5228{ 5229 int cpu = smp_processor_id(); 5230 struct rq *rq = cpu_rq(cpu); 5231 rq->age_stamp = sched_clock_cpu(cpu); 5232} 5233 5234static int sched_cpu_active(struct notifier_block *nfb, 5235 unsigned long action, void *hcpu) 5236{ 5237 switch (action & ~CPU_TASKS_FROZEN) { 5238 case CPU_STARTING: 5239 set_cpu_rq_start_time(); 5240 return NOTIFY_OK; 5241 case CPU_DOWN_FAILED: 5242 set_cpu_active((long)hcpu, true); 5243 return NOTIFY_OK; 5244 default: 5245 return NOTIFY_DONE; 5246 } 5247} 5248 5249static int sched_cpu_inactive(struct notifier_block *nfb, 5250 unsigned long action, void *hcpu) 5251{ 5252 unsigned long flags; 5253 long cpu = (long)hcpu; 5254 5255 switch (action & ~CPU_TASKS_FROZEN) { 5256 case CPU_DOWN_PREPARE: 5257 set_cpu_active(cpu, false); 5258 5259 /* explicitly allow suspend */ 5260 if (!(action & CPU_TASKS_FROZEN)) { 5261 struct dl_bw *dl_b = dl_bw_of(cpu); 5262 bool overflow; 5263 int cpus; 5264 5265 raw_spin_lock_irqsave(&dl_b->lock, flags); 5266 cpus = dl_bw_cpus(cpu); 5267 overflow = __dl_overflow(dl_b, cpus, 0, 0); 5268 raw_spin_unlock_irqrestore(&dl_b->lock, flags); 5269 5270 if (overflow) 5271 return notifier_from_errno(-EBUSY); 5272 } 5273 return NOTIFY_OK; 5274 } 5275 5276 return NOTIFY_DONE; 5277} 5278 5279static int __init migration_init(void) 5280{ 5281 void *cpu = (void *)(long)smp_processor_id(); 5282 int err; 5283 5284 /* Initialize migration for the boot CPU */ 5285 err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); 5286 BUG_ON(err == NOTIFY_BAD); 5287 migration_call(&migration_notifier, CPU_ONLINE, cpu); 5288 register_cpu_notifier(&migration_notifier); 5289 5290 /* Register cpu active notifiers */ 5291 cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE); 5292 cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE); 5293 5294 return 0; 5295} 5296early_initcall(migration_init); 5297#endif 5298 5299#ifdef CONFIG_SMP 5300 5301static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */ 5302 5303#ifdef CONFIG_SCHED_DEBUG 5304 5305static __read_mostly int sched_debug_enabled; 5306 5307static int __init sched_debug_setup(char *str) 5308{ 5309 sched_debug_enabled = 1; 5310 5311 return 0; 5312} 5313early_param("sched_debug", sched_debug_setup); 5314 5315static inline bool sched_debug(void) 5316{ 5317 return sched_debug_enabled; 5318} 5319 5320static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, 5321 struct cpumask *groupmask) 5322{ 5323 struct sched_group *group = sd->groups; 5324 char str[256]; 5325 5326 cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd)); 5327 cpumask_clear(groupmask); 5328 5329 printk(KERN_DEBUG "%*s domain %d: ", level, "", level); 5330 5331 if (!(sd->flags & SD_LOAD_BALANCE)) { 5332 printk("does not load-balance\n"); 5333 if (sd->parent) 5334 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain" 5335 " has parent"); 5336 return -1; 5337 } 5338 5339 printk(KERN_CONT "span %s level %s\n", str, sd->name); 5340 5341 if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) { 5342 printk(KERN_ERR "ERROR: domain->span does not contain " 5343 "CPU%d\n", cpu); 5344 } 5345 if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) { 5346 printk(KERN_ERR "ERROR: domain->groups does not contain" 5347 " CPU%d\n", cpu); 5348 } 5349 5350 printk(KERN_DEBUG "%*s groups:", level + 1, ""); 5351 do { 5352 if (!group) { 5353 printk("\n"); 5354 printk(KERN_ERR "ERROR: group is NULL\n"); 5355 break; 5356 } 5357 5358 /* 5359 * Even though we initialize ->capacity to something semi-sane, 5360 * we leave capacity_orig unset. This allows us to detect if 5361 * domain iteration is still funny without causing /0 traps. 5362 */ 5363 if (!group->sgc->capacity_orig) { 5364 printk(KERN_CONT "\n"); 5365 printk(KERN_ERR "ERROR: domain->cpu_capacity not set\n"); 5366 break; 5367 } 5368 5369 if (!cpumask_weight(sched_group_cpus(group))) { 5370 printk(KERN_CONT "\n"); 5371 printk(KERN_ERR "ERROR: empty group\n"); 5372 break; 5373 } 5374 5375 if (!(sd->flags & SD_OVERLAP) && 5376 cpumask_intersects(groupmask, sched_group_cpus(group))) { 5377 printk(KERN_CONT "\n"); 5378 printk(KERN_ERR "ERROR: repeated CPUs\n"); 5379 break; 5380 } 5381 5382 cpumask_or(groupmask, groupmask, sched_group_cpus(group)); 5383 5384 cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group)); 5385 5386 printk(KERN_CONT " %s", str); 5387 if (group->sgc->capacity != SCHED_CAPACITY_SCALE) { 5388 printk(KERN_CONT " (cpu_capacity = %d)", 5389 group->sgc->capacity); 5390 } 5391 5392 group = group->next; 5393 } while (group != sd->groups); 5394 printk(KERN_CONT "\n"); 5395 5396 if (!cpumask_equal(sched_domain_span(sd), groupmask)) 5397 printk(KERN_ERR "ERROR: groups don't span domain->span\n"); 5398 5399 if (sd->parent && 5400 !cpumask_subset(groupmask, sched_domain_span(sd->parent))) 5401 printk(KERN_ERR "ERROR: parent span is not a superset " 5402 "of domain->span\n"); 5403 return 0; 5404} 5405 5406static void sched_domain_debug(struct sched_domain *sd, int cpu) 5407{ 5408 int level = 0; 5409 5410 if (!sched_debug_enabled) 5411 return; 5412 5413 if (!sd) { 5414 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); 5415 return; 5416 } 5417 5418 printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); 5419 5420 for (;;) { 5421 if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask)) 5422 break; 5423 level++; 5424 sd = sd->parent; 5425 if (!sd) 5426 break; 5427 } 5428} 5429#else /* !CONFIG_SCHED_DEBUG */ 5430# define sched_domain_debug(sd, cpu) do { } while (0) 5431static inline bool sched_debug(void) 5432{ 5433 return false; 5434} 5435#endif /* CONFIG_SCHED_DEBUG */ 5436 5437static int sd_degenerate(struct sched_domain *sd) 5438{ 5439 if (cpumask_weight(sched_domain_span(sd)) == 1) 5440 return 1; 5441 5442 /* Following flags need at least 2 groups */ 5443 if (sd->flags & (SD_LOAD_BALANCE | 5444 SD_BALANCE_NEWIDLE | 5445 SD_BALANCE_FORK | 5446 SD_BALANCE_EXEC | 5447 SD_SHARE_CPUCAPACITY | 5448 SD_SHARE_PKG_RESOURCES | 5449 SD_SHARE_POWERDOMAIN)) { 5450 if (sd->groups != sd->groups->next) 5451 return 0; 5452 } 5453 5454 /* Following flags don't use groups */ 5455 if (sd->flags & (SD_WAKE_AFFINE)) 5456 return 0; 5457 5458 return 1; 5459} 5460 5461static int 5462sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) 5463{ 5464 unsigned long cflags = sd->flags, pflags = parent->flags; 5465 5466 if (sd_degenerate(parent)) 5467 return 1; 5468 5469 if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent))) 5470 return 0; 5471 5472 /* Flags needing groups don't count if only 1 group in parent */ 5473 if (parent->groups == parent->groups->next) { 5474 pflags &= ~(SD_LOAD_BALANCE | 5475 SD_BALANCE_NEWIDLE | 5476 SD_BALANCE_FORK | 5477 SD_BALANCE_EXEC | 5478 SD_SHARE_CPUCAPACITY | 5479 SD_SHARE_PKG_RESOURCES | 5480 SD_PREFER_SIBLING | 5481 SD_SHARE_POWERDOMAIN); 5482 if (nr_node_ids == 1) 5483 pflags &= ~SD_SERIALIZE; 5484 } 5485 if (~cflags & pflags) 5486 return 0; 5487 5488 return 1; 5489} 5490 5491static void free_rootdomain(struct rcu_head *rcu) 5492{ 5493 struct root_domain *rd = container_of(rcu, struct root_domain, rcu); 5494 5495 cpupri_cleanup(&rd->cpupri); 5496 cpudl_cleanup(&rd->cpudl); 5497 free_cpumask_var(rd->dlo_mask); 5498 free_cpumask_var(rd->rto_mask); 5499 free_cpumask_var(rd->online); 5500 free_cpumask_var(rd->span); 5501 kfree(rd); 5502} 5503 5504static void rq_attach_root(struct rq *rq, struct root_domain *rd) 5505{ 5506 struct root_domain *old_rd = NULL; 5507 unsigned long flags; 5508 5509 raw_spin_lock_irqsave(&rq->lock, flags); 5510 5511 if (rq->rd) { 5512 old_rd = rq->rd; 5513 5514 if (cpumask_test_cpu(rq->cpu, old_rd->online)) 5515 set_rq_offline(rq); 5516 5517 cpumask_clear_cpu(rq->cpu, old_rd->span); 5518 5519 /* 5520 * If we dont want to free the old_rd yet then 5521 * set old_rd to NULL to skip the freeing later 5522 * in this function: 5523 */ 5524 if (!atomic_dec_and_test(&old_rd->refcount)) 5525 old_rd = NULL; 5526 } 5527 5528 atomic_inc(&rd->refcount); 5529 rq->rd = rd; 5530 5531 cpumask_set_cpu(rq->cpu, rd->span); 5532 if (cpumask_test_cpu(rq->cpu, cpu_active_mask)) 5533 set_rq_online(rq); 5534 5535 raw_spin_unlock_irqrestore(&rq->lock, flags); 5536 5537 if (old_rd) 5538 call_rcu_sched(&old_rd->rcu, free_rootdomain); 5539} 5540 5541static int init_rootdomain(struct root_domain *rd) 5542{ 5543 memset(rd, 0, sizeof(*rd)); 5544 5545 if (!alloc_cpumask_var(&rd->span, GFP_KERNEL)) 5546 goto out; 5547 if (!alloc_cpumask_var(&rd->online, GFP_KERNEL)) 5548 goto free_span; 5549 if (!alloc_cpumask_var(&rd->dlo_mask, GFP_KERNEL)) 5550 goto free_online; 5551 if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL)) 5552 goto free_dlo_mask; 5553 5554 init_dl_bw(&rd->dl_bw); 5555 if (cpudl_init(&rd->cpudl) != 0) 5556 goto free_dlo_mask; 5557 5558 if (cpupri_init(&rd->cpupri) != 0) 5559 goto free_rto_mask; 5560 return 0; 5561 5562free_rto_mask: 5563 free_cpumask_var(rd->rto_mask); 5564free_dlo_mask: 5565 free_cpumask_var(rd->dlo_mask); 5566free_online: 5567 free_cpumask_var(rd->online); 5568free_span: 5569 free_cpumask_var(rd->span); 5570out: 5571 return -ENOMEM; 5572} 5573 5574/* 5575 * By default the system creates a single root-domain with all cpus as 5576 * members (mimicking the global state we have today). 5577 */ 5578struct root_domain def_root_domain; 5579 5580static void init_defrootdomain(void) 5581{ 5582 init_rootdomain(&def_root_domain); 5583 5584 atomic_set(&def_root_domain.refcount, 1); 5585} 5586 5587static struct root_domain *alloc_rootdomain(void) 5588{ 5589 struct root_domain *rd; 5590 5591 rd = kmalloc(sizeof(*rd), GFP_KERNEL); 5592 if (!rd) 5593 return NULL; 5594 5595 if (init_rootdomain(rd) != 0) { 5596 kfree(rd); 5597 return NULL; 5598 } 5599 5600 return rd; 5601} 5602 5603static void free_sched_groups(struct sched_group *sg, int free_sgc) 5604{ 5605 struct sched_group *tmp, *first; 5606 5607 if (!sg) 5608 return; 5609 5610 first = sg; 5611 do { 5612 tmp = sg->next; 5613 5614 if (free_sgc && atomic_dec_and_test(&sg->sgc->ref)) 5615 kfree(sg->sgc); 5616 5617 kfree(sg); 5618 sg = tmp; 5619 } while (sg != first); 5620} 5621 5622static void free_sched_domain(struct rcu_head *rcu) 5623{ 5624 struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu); 5625 5626 /* 5627 * If its an overlapping domain it has private groups, iterate and 5628 * nuke them all. 5629 */ 5630 if (sd->flags & SD_OVERLAP) { 5631 free_sched_groups(sd->groups, 1); 5632 } else if (atomic_dec_and_test(&sd->groups->ref)) { 5633 kfree(sd->groups->sgc); 5634 kfree(sd->groups); 5635 } 5636 kfree(sd); 5637} 5638 5639static void destroy_sched_domain(struct sched_domain *sd, int cpu) 5640{ 5641 call_rcu(&sd->rcu, free_sched_domain); 5642} 5643 5644static void destroy_sched_domains(struct sched_domain *sd, int cpu) 5645{ 5646 for (; sd; sd = sd->parent) 5647 destroy_sched_domain(sd, cpu); 5648} 5649 5650/* 5651 * Keep a special pointer to the highest sched_domain that has 5652 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this 5653 * allows us to avoid some pointer chasing select_idle_sibling(). 5654 * 5655 * Also keep a unique ID per domain (we use the first cpu number in 5656 * the cpumask of the domain), this allows us to quickly tell if 5657 * two cpus are in the same cache domain, see cpus_share_cache(). 5658 */ 5659DEFINE_PER_CPU(struct sched_domain *, sd_llc); 5660DEFINE_PER_CPU(int, sd_llc_size); 5661DEFINE_PER_CPU(int, sd_llc_id); 5662DEFINE_PER_CPU(struct sched_domain *, sd_numa); 5663DEFINE_PER_CPU(struct sched_domain *, sd_busy); 5664DEFINE_PER_CPU(struct sched_domain *, sd_asym); 5665 5666static void update_top_cache_domain(int cpu) 5667{ 5668 struct sched_domain *sd; 5669 struct sched_domain *busy_sd = NULL; 5670 int id = cpu; 5671 int size = 1; 5672 5673 sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES); 5674 if (sd) { 5675 id = cpumask_first(sched_domain_span(sd)); 5676 size = cpumask_weight(sched_domain_span(sd)); 5677 busy_sd = sd->parent; /* sd_busy */ 5678 } 5679 rcu_assign_pointer(per_cpu(sd_busy, cpu), busy_sd); 5680 5681 rcu_assign_pointer(per_cpu(sd_llc, cpu), sd); 5682 per_cpu(sd_llc_size, cpu) = size; 5683 per_cpu(sd_llc_id, cpu) = id; 5684 5685 sd = lowest_flag_domain(cpu, SD_NUMA); 5686 rcu_assign_pointer(per_cpu(sd_numa, cpu), sd); 5687 5688 sd = highest_flag_domain(cpu, SD_ASYM_PACKING); 5689 rcu_assign_pointer(per_cpu(sd_asym, cpu), sd); 5690} 5691 5692/* 5693 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must 5694 * hold the hotplug lock. 5695 */ 5696static void 5697cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) 5698{ 5699 struct rq *rq = cpu_rq(cpu); 5700 struct sched_domain *tmp; 5701 5702 /* Remove the sched domains which do not contribute to scheduling. */ 5703 for (tmp = sd; tmp; ) { 5704 struct sched_domain *parent = tmp->parent; 5705 if (!parent) 5706 break; 5707 5708 if (sd_parent_degenerate(tmp, parent)) { 5709 tmp->parent = parent->parent; 5710 if (parent->parent) 5711 parent->parent->child = tmp; 5712 /* 5713 * Transfer SD_PREFER_SIBLING down in case of a 5714 * degenerate parent; the spans match for this 5715 * so the property transfers. 5716 */ 5717 if (parent->flags & SD_PREFER_SIBLING) 5718 tmp->flags |= SD_PREFER_SIBLING; 5719 destroy_sched_domain(parent, cpu); 5720 } else 5721 tmp = tmp->parent; 5722 } 5723 5724 if (sd && sd_degenerate(sd)) { 5725 tmp = sd; 5726 sd = sd->parent; 5727 destroy_sched_domain(tmp, cpu); 5728 if (sd) 5729 sd->child = NULL; 5730 } 5731 5732 sched_domain_debug(sd, cpu); 5733 5734 rq_attach_root(rq, rd); 5735 tmp = rq->sd; 5736 rcu_assign_pointer(rq->sd, sd); 5737 destroy_sched_domains(tmp, cpu); 5738 5739 update_top_cache_domain(cpu); 5740} 5741 5742/* cpus with isolated domains */ 5743static cpumask_var_t cpu_isolated_map; 5744 5745/* Setup the mask of cpus configured for isolated domains */ 5746static int __init isolated_cpu_setup(char *str) 5747{ 5748 alloc_bootmem_cpumask_var(&cpu_isolated_map); 5749 cpulist_parse(str, cpu_isolated_map); 5750 return 1; 5751} 5752 5753__setup("isolcpus=", isolated_cpu_setup); 5754 5755struct s_data { 5756 struct sched_domain ** __percpu sd; 5757 struct root_domain *rd; 5758}; 5759 5760enum s_alloc { 5761 sa_rootdomain, 5762 sa_sd, 5763 sa_sd_storage, 5764 sa_none, 5765}; 5766 5767/* 5768 * Build an iteration mask that can exclude certain CPUs from the upwards 5769 * domain traversal. 5770 * 5771 * Asymmetric node setups can result in situations where the domain tree is of 5772 * unequal depth, make sure to skip domains that already cover the entire 5773 * range. 5774 * 5775 * In that case build_sched_domains() will have terminated the iteration early 5776 * and our sibling sd spans will be empty. Domains should always include the 5777 * cpu they're built on, so check that. 5778 * 5779 */ 5780static void build_group_mask(struct sched_domain *sd, struct sched_group *sg) 5781{ 5782 const struct cpumask *span = sched_domain_span(sd); 5783 struct sd_data *sdd = sd->private; 5784 struct sched_domain *sibling; 5785 int i; 5786 5787 for_each_cpu(i, span) { 5788 sibling = *per_cpu_ptr(sdd->sd, i); 5789 if (!cpumask_test_cpu(i, sched_domain_span(sibling))) 5790 continue; 5791 5792 cpumask_set_cpu(i, sched_group_mask(sg)); 5793 } 5794} 5795 5796/* 5797 * Return the canonical balance cpu for this group, this is the first cpu 5798 * of this group that's also in the iteration mask. 5799 */ 5800int group_balance_cpu(struct sched_group *sg) 5801{ 5802 return cpumask_first_and(sched_group_cpus(sg), sched_group_mask(sg)); 5803} 5804 5805static int 5806build_overlap_sched_groups(struct sched_domain *sd, int cpu) 5807{ 5808 struct sched_group *first = NULL, *last = NULL, *groups = NULL, *sg; 5809 const struct cpumask *span = sched_domain_span(sd); 5810 struct cpumask *covered = sched_domains_tmpmask; 5811 struct sd_data *sdd = sd->private; 5812 struct sched_domain *sibling; 5813 int i; 5814 5815 cpumask_clear(covered); 5816 5817 for_each_cpu(i, span) { 5818 struct cpumask *sg_span; 5819 5820 if (cpumask_test_cpu(i, covered)) 5821 continue; 5822 5823 sibling = *per_cpu_ptr(sdd->sd, i); 5824 5825 /* See the comment near build_group_mask(). */ 5826 if (!cpumask_test_cpu(i, sched_domain_span(sibling))) 5827 continue; 5828 5829 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), 5830 GFP_KERNEL, cpu_to_node(cpu)); 5831 5832 if (!sg) 5833 goto fail; 5834 5835 sg_span = sched_group_cpus(sg); 5836 if (sibling->child) 5837 cpumask_copy(sg_span, sched_domain_span(sibling->child)); 5838 else 5839 cpumask_set_cpu(i, sg_span); 5840 5841 cpumask_or(covered, covered, sg_span); 5842 5843 sg->sgc = *per_cpu_ptr(sdd->sgc, i); 5844 if (atomic_inc_return(&sg->sgc->ref) == 1) 5845 build_group_mask(sd, sg); 5846 5847 /* 5848 * Initialize sgc->capacity such that even if we mess up the 5849 * domains and no possible iteration will get us here, we won't 5850 * die on a /0 trap. 5851 */ 5852 sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sg_span); 5853 sg->sgc->capacity_orig = sg->sgc->capacity; 5854 5855 /* 5856 * Make sure the first group of this domain contains the 5857 * canonical balance cpu. Otherwise the sched_domain iteration 5858 * breaks. See update_sg_lb_stats(). 5859 */ 5860 if ((!groups && cpumask_test_cpu(cpu, sg_span)) || 5861 group_balance_cpu(sg) == cpu) 5862 groups = sg; 5863 5864 if (!first) 5865 first = sg; 5866 if (last) 5867 last->next = sg; 5868 last = sg; 5869 last->next = first; 5870 } 5871 sd->groups = groups; 5872 5873 return 0; 5874 5875fail: 5876 free_sched_groups(first, 0); 5877 5878 return -ENOMEM; 5879} 5880 5881static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg) 5882{ 5883 struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu); 5884 struct sched_domain *child = sd->child; 5885 5886 if (child) 5887 cpu = cpumask_first(sched_domain_span(child)); 5888 5889 if (sg) { 5890 *sg = *per_cpu_ptr(sdd->sg, cpu); 5891 (*sg)->sgc = *per_cpu_ptr(sdd->sgc, cpu); 5892 atomic_set(&(*sg)->sgc->ref, 1); /* for claim_allocations */ 5893 } 5894 5895 return cpu; 5896} 5897 5898/* 5899 * build_sched_groups will build a circular linked list of the groups 5900 * covered by the given span, and will set each group's ->cpumask correctly, 5901 * and ->cpu_capacity to 0. 5902 * 5903 * Assumes the sched_domain tree is fully constructed 5904 */ 5905static int 5906build_sched_groups(struct sched_domain *sd, int cpu) 5907{ 5908 struct sched_group *first = NULL, *last = NULL; 5909 struct sd_data *sdd = sd->private; 5910 const struct cpumask *span = sched_domain_span(sd); 5911 struct cpumask *covered; 5912 int i; 5913 5914 get_group(cpu, sdd, &sd->groups); 5915 atomic_inc(&sd->groups->ref); 5916 5917 if (cpu != cpumask_first(span)) 5918 return 0; 5919 5920 lockdep_assert_held(&sched_domains_mutex); 5921 covered = sched_domains_tmpmask; 5922 5923 cpumask_clear(covered); 5924 5925 for_each_cpu(i, span) { 5926 struct sched_group *sg; 5927 int group, j; 5928 5929 if (cpumask_test_cpu(i, covered)) 5930 continue; 5931 5932 group = get_group(i, sdd, &sg); 5933 cpumask_setall(sched_group_mask(sg)); 5934 5935 for_each_cpu(j, span) { 5936 if (get_group(j, sdd, NULL) != group) 5937 continue; 5938 5939 cpumask_set_cpu(j, covered); 5940 cpumask_set_cpu(j, sched_group_cpus(sg)); 5941 } 5942 5943 if (!first) 5944 first = sg; 5945 if (last) 5946 last->next = sg; 5947 last = sg; 5948 } 5949 last->next = first; 5950 5951 return 0; 5952} 5953 5954/* 5955 * Initialize sched groups cpu_capacity. 5956 * 5957 * cpu_capacity indicates the capacity of sched group, which is used while 5958 * distributing the load between different sched groups in a sched domain. 5959 * Typically cpu_capacity for all the groups in a sched domain will be same 5960 * unless there are asymmetries in the topology. If there are asymmetries, 5961 * group having more cpu_capacity will pickup more load compared to the 5962 * group having less cpu_capacity. 5963 */ 5964static void init_sched_groups_capacity(int cpu, struct sched_domain *sd) 5965{ 5966 struct sched_group *sg = sd->groups; 5967 5968 WARN_ON(!sg); 5969 5970 do { 5971 sg->group_weight = cpumask_weight(sched_group_cpus(sg)); 5972 sg = sg->next; 5973 } while (sg != sd->groups); 5974 5975 if (cpu != group_balance_cpu(sg)) 5976 return; 5977 5978 update_group_capacity(sd, cpu); 5979 atomic_set(&sg->sgc->nr_busy_cpus, sg->group_weight); 5980} 5981 5982/* 5983 * Initializers for schedule domains 5984 * Non-inlined to reduce accumulated stack pressure in build_sched_domains() 5985 */ 5986 5987static int default_relax_domain_level = -1; 5988int sched_domain_level_max; 5989 5990static int __init setup_relax_domain_level(char *str) 5991{ 5992 if (kstrtoint(str, 0, &default_relax_domain_level)) 5993 pr_warn("Unable to set relax_domain_level\n"); 5994 5995 return 1; 5996} 5997__setup("relax_domain_level=", setup_relax_domain_level); 5998 5999static void set_domain_attribute(struct sched_domain *sd, 6000 struct sched_domain_attr *attr) 6001{ 6002 int request; 6003 6004 if (!attr || attr->relax_domain_level < 0) { 6005 if (default_relax_domain_level < 0) 6006 return; 6007 else 6008 request = default_relax_domain_level; 6009 } else 6010 request = attr->relax_domain_level; 6011 if (request < sd->level) { 6012 /* turn off idle balance on this domain */ 6013 sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); 6014 } else { 6015 /* turn on idle balance on this domain */ 6016 sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); 6017 } 6018} 6019 6020static void __sdt_free(const struct cpumask *cpu_map); 6021static int __sdt_alloc(const struct cpumask *cpu_map); 6022 6023static void __free_domain_allocs(struct s_data *d, enum s_alloc what, 6024 const struct cpumask *cpu_map) 6025{ 6026 switch (what) { 6027 case sa_rootdomain: 6028 if (!atomic_read(&d->rd->refcount)) 6029 free_rootdomain(&d->rd->rcu); /* fall through */ 6030 case sa_sd: 6031 free_percpu(d->sd); /* fall through */ 6032 case sa_sd_storage: 6033 __sdt_free(cpu_map); /* fall through */ 6034 case sa_none: 6035 break; 6036 } 6037} 6038 6039static enum s_alloc __visit_domain_allocation_hell(struct s_data *d, 6040 const struct cpumask *cpu_map) 6041{ 6042 memset(d, 0, sizeof(*d)); 6043 6044 if (__sdt_alloc(cpu_map)) 6045 return sa_sd_storage; 6046 d->sd = alloc_percpu(struct sched_domain *); 6047 if (!d->sd) 6048 return sa_sd_storage; 6049 d->rd = alloc_rootdomain(); 6050 if (!d->rd) 6051 return sa_sd; 6052 return sa_rootdomain; 6053} 6054 6055/* 6056 * NULL the sd_data elements we've used to build the sched_domain and 6057 * sched_group structure so that the subsequent __free_domain_allocs() 6058 * will not free the data we're using. 6059 */ 6060static void claim_allocations(int cpu, struct sched_domain *sd) 6061{ 6062 struct sd_data *sdd = sd->private; 6063 6064 WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd); 6065 *per_cpu_ptr(sdd->sd, cpu) = NULL; 6066 6067 if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref)) 6068 *per_cpu_ptr(sdd->sg, cpu) = NULL; 6069 6070 if (atomic_read(&(*per_cpu_ptr(sdd->sgc, cpu))->ref)) 6071 *per_cpu_ptr(sdd->sgc, cpu) = NULL; 6072} 6073 6074#ifdef CONFIG_NUMA 6075static int sched_domains_numa_levels; 6076static int *sched_domains_numa_distance; 6077static struct cpumask ***sched_domains_numa_masks; 6078static int sched_domains_curr_level; 6079#endif 6080 6081/* 6082 * SD_flags allowed in topology descriptions. 6083 * 6084 * SD_SHARE_CPUCAPACITY - describes SMT topologies 6085 * SD_SHARE_PKG_RESOURCES - describes shared caches 6086 * SD_NUMA - describes NUMA topologies 6087 * SD_SHARE_POWERDOMAIN - describes shared power domain 6088 * 6089 * Odd one out: 6090 * SD_ASYM_PACKING - describes SMT quirks 6091 */ 6092#define TOPOLOGY_SD_FLAGS \ 6093 (SD_SHARE_CPUCAPACITY | \ 6094 SD_SHARE_PKG_RESOURCES | \ 6095 SD_NUMA | \ 6096 SD_ASYM_PACKING | \ 6097 SD_SHARE_POWERDOMAIN) 6098 6099static struct sched_domain * 6100sd_init(struct sched_domain_topology_level *tl, int cpu) 6101{ 6102 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); 6103 int sd_weight, sd_flags = 0; 6104 6105#ifdef CONFIG_NUMA 6106 /* 6107 * Ugly hack to pass state to sd_numa_mask()... 6108 */ 6109 sched_domains_curr_level = tl->numa_level; 6110#endif 6111 6112 sd_weight = cpumask_weight(tl->mask(cpu)); 6113 6114 if (tl->sd_flags) 6115 sd_flags = (*tl->sd_flags)(); 6116 if (WARN_ONCE(sd_flags & ~TOPOLOGY_SD_FLAGS, 6117 "wrong sd_flags in topology description\n")) 6118 sd_flags &= ~TOPOLOGY_SD_FLAGS; 6119 6120 *sd = (struct sched_domain){ 6121 .min_interval = sd_weight, 6122 .max_interval = 2*sd_weight, 6123 .busy_factor = 32, 6124 .imbalance_pct = 125, 6125 6126 .cache_nice_tries = 0, 6127 .busy_idx = 0, 6128 .idle_idx = 0, 6129 .newidle_idx = 0, 6130 .wake_idx = 0, 6131 .forkexec_idx = 0, 6132 6133 .flags = 1*SD_LOAD_BALANCE 6134 | 1*SD_BALANCE_NEWIDLE 6135 | 1*SD_BALANCE_EXEC 6136 | 1*SD_BALANCE_FORK 6137 | 0*SD_BALANCE_WAKE 6138 | 1*SD_WAKE_AFFINE 6139 | 0*SD_SHARE_CPUCAPACITY 6140 | 0*SD_SHARE_PKG_RESOURCES 6141 | 0*SD_SERIALIZE 6142 | 0*SD_PREFER_SIBLING 6143 | 0*SD_NUMA 6144 | sd_flags 6145 , 6146 6147 .last_balance = jiffies, 6148 .balance_interval = sd_weight, 6149 .smt_gain = 0, 6150 .max_newidle_lb_cost = 0, 6151 .next_decay_max_lb_cost = jiffies, 6152#ifdef CONFIG_SCHED_DEBUG 6153 .name = tl->name, 6154#endif 6155 }; 6156 6157 /* 6158 * Convert topological properties into behaviour. 6159 */ 6160 6161 if (sd->flags & SD_SHARE_CPUCAPACITY) { 6162 sd->imbalance_pct = 110; 6163 sd->smt_gain = 1178; /* ~15% */ 6164 6165 } else if (sd->flags & SD_SHARE_PKG_RESOURCES) { 6166 sd->imbalance_pct = 117; 6167 sd->cache_nice_tries = 1; 6168 sd->busy_idx = 2; 6169 6170#ifdef CONFIG_NUMA 6171 } else if (sd->flags & SD_NUMA) { 6172 sd->cache_nice_tries = 2; 6173 sd->busy_idx = 3; 6174 sd->idle_idx = 2; 6175 6176 sd->flags |= SD_SERIALIZE; 6177 if (sched_domains_numa_distance[tl->numa_level] > RECLAIM_DISTANCE) { 6178 sd->flags &= ~(SD_BALANCE_EXEC | 6179 SD_BALANCE_FORK | 6180 SD_WAKE_AFFINE); 6181 } 6182 6183#endif 6184 } else { 6185 sd->flags |= SD_PREFER_SIBLING; 6186 sd->cache_nice_tries = 1; 6187 sd->busy_idx = 2; 6188 sd->idle_idx = 1; 6189 } 6190 6191 sd->private = &tl->data; 6192 6193 return sd; 6194} 6195 6196/* 6197 * Topology list, bottom-up. 6198 */ 6199static struct sched_domain_topology_level default_topology[] = { 6200#ifdef CONFIG_SCHED_SMT 6201 { cpu_smt_mask, cpu_smt_flags, SD_INIT_NAME(SMT) }, 6202#endif 6203#ifdef CONFIG_SCHED_MC 6204 { cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) }, 6205#endif 6206 { cpu_cpu_mask, SD_INIT_NAME(DIE) }, 6207 { NULL, }, 6208}; 6209 6210struct sched_domain_topology_level *sched_domain_topology = default_topology; 6211 6212#define for_each_sd_topology(tl) \ 6213 for (tl = sched_domain_topology; tl->mask; tl++) 6214 6215void set_sched_topology(struct sched_domain_topology_level *tl) 6216{ 6217 sched_domain_topology = tl; 6218} 6219 6220#ifdef CONFIG_NUMA 6221 6222static const struct cpumask *sd_numa_mask(int cpu) 6223{ 6224 return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)]; 6225} 6226 6227static void sched_numa_warn(const char *str) 6228{ 6229 static int done = false; 6230 int i,j; 6231 6232 if (done) 6233 return; 6234 6235 done = true; 6236 6237 printk(KERN_WARNING "ERROR: %s\n\n", str); 6238 6239 for (i = 0; i < nr_node_ids; i++) { 6240 printk(KERN_WARNING " "); 6241 for (j = 0; j < nr_node_ids; j++) 6242 printk(KERN_CONT "%02d ", node_distance(i,j)); 6243 printk(KERN_CONT "\n"); 6244 } 6245 printk(KERN_WARNING "\n"); 6246} 6247 6248static bool find_numa_distance(int distance) 6249{ 6250 int i; 6251 6252 if (distance == node_distance(0, 0)) 6253 return true; 6254 6255 for (i = 0; i < sched_domains_numa_levels; i++) { 6256 if (sched_domains_numa_distance[i] == distance) 6257 return true; 6258 } 6259 6260 return false; 6261} 6262 6263static void sched_init_numa(void) 6264{ 6265 int next_distance, curr_distance = node_distance(0, 0); 6266 struct sched_domain_topology_level *tl; 6267 int level = 0; 6268 int i, j, k; 6269 6270 sched_domains_numa_distance = kzalloc(sizeof(int) * nr_node_ids, GFP_KERNEL); 6271 if (!sched_domains_numa_distance) 6272 return; 6273 6274 /* 6275 * O(nr_nodes^2) deduplicating selection sort -- in order to find the 6276 * unique distances in the node_distance() table. 6277 * 6278 * Assumes node_distance(0,j) includes all distances in 6279 * node_distance(i,j) in order to avoid cubic time. 6280 */ 6281 next_distance = curr_distance; 6282 for (i = 0; i < nr_node_ids; i++) { 6283 for (j = 0; j < nr_node_ids; j++) { 6284 for (k = 0; k < nr_node_ids; k++) { 6285 int distance = node_distance(i, k); 6286 6287 if (distance > curr_distance && 6288 (distance < next_distance || 6289 next_distance == curr_distance)) 6290 next_distance = distance; 6291 6292 /* 6293 * While not a strong assumption it would be nice to know 6294 * about cases where if node A is connected to B, B is not 6295 * equally connected to A. 6296 */ 6297 if (sched_debug() && node_distance(k, i) != distance) 6298 sched_numa_warn("Node-distance not symmetric"); 6299 6300 if (sched_debug() && i && !find_numa_distance(distance)) 6301 sched_numa_warn("Node-0 not representative"); 6302 } 6303 if (next_distance != curr_distance) { 6304 sched_domains_numa_distance[level++] = next_distance; 6305 sched_domains_numa_levels = level; 6306 curr_distance = next_distance; 6307 } else break; 6308 } 6309 6310 /* 6311 * In case of sched_debug() we verify the above assumption. 6312 */ 6313 if (!sched_debug()) 6314 break; 6315 } 6316 /* 6317 * 'level' contains the number of unique distances, excluding the 6318 * identity distance node_distance(i,i). 6319 * 6320 * The sched_domains_numa_distance[] array includes the actual distance 6321 * numbers. 6322 */ 6323 6324 /* 6325 * Here, we should temporarily reset sched_domains_numa_levels to 0. 6326 * If it fails to allocate memory for array sched_domains_numa_masks[][], 6327 * the array will contain less then 'level' members. This could be 6328 * dangerous when we use it to iterate array sched_domains_numa_masks[][] 6329 * in other functions. 6330 * 6331 * We reset it to 'level' at the end of this function. 6332 */ 6333 sched_domains_numa_levels = 0; 6334 6335 sched_domains_numa_masks = kzalloc(sizeof(void *) * level, GFP_KERNEL); 6336 if (!sched_domains_numa_masks) 6337 return; 6338 6339 /* 6340 * Now for each level, construct a mask per node which contains all 6341 * cpus of nodes that are that many hops away from us. 6342 */ 6343 for (i = 0; i < level; i++) { 6344 sched_domains_numa_masks[i] = 6345 kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL); 6346 if (!sched_domains_numa_masks[i]) 6347 return; 6348 6349 for (j = 0; j < nr_node_ids; j++) { 6350 struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL); 6351 if (!mask) 6352 return; 6353 6354 sched_domains_numa_masks[i][j] = mask; 6355 6356 for (k = 0; k < nr_node_ids; k++) { 6357 if (node_distance(j, k) > sched_domains_numa_distance[i]) 6358 continue; 6359 6360 cpumask_or(mask, mask, cpumask_of_node(k)); 6361 } 6362 } 6363 } 6364 6365 /* Compute default topology size */ 6366 for (i = 0; sched_domain_topology[i].mask; i++); 6367 6368 tl = kzalloc((i + level + 1) * 6369 sizeof(struct sched_domain_topology_level), GFP_KERNEL); 6370 if (!tl) 6371 return; 6372 6373 /* 6374 * Copy the default topology bits.. 6375 */ 6376 for (i = 0; sched_domain_topology[i].mask; i++) 6377 tl[i] = sched_domain_topology[i]; 6378 6379 /* 6380 * .. and append 'j' levels of NUMA goodness. 6381 */ 6382 for (j = 0; j < level; i++, j++) { 6383 tl[i] = (struct sched_domain_topology_level){ 6384 .mask = sd_numa_mask, 6385 .sd_flags = cpu_numa_flags, 6386 .flags = SDTL_OVERLAP, 6387 .numa_level = j, 6388 SD_INIT_NAME(NUMA) 6389 }; 6390 } 6391 6392 sched_domain_topology = tl; 6393 6394 sched_domains_numa_levels = level; 6395} 6396 6397static void sched_domains_numa_masks_set(int cpu) 6398{ 6399 int i, j; 6400 int node = cpu_to_node(cpu); 6401 6402 for (i = 0; i < sched_domains_numa_levels; i++) { 6403 for (j = 0; j < nr_node_ids; j++) { 6404 if (node_distance(j, node) <= sched_domains_numa_distance[i]) 6405 cpumask_set_cpu(cpu, sched_domains_numa_masks[i][j]); 6406 } 6407 } 6408} 6409 6410static void sched_domains_numa_masks_clear(int cpu) 6411{ 6412 int i, j; 6413 for (i = 0; i < sched_domains_numa_levels; i++) { 6414 for (j = 0; j < nr_node_ids; j++) 6415 cpumask_clear_cpu(cpu, sched_domains_numa_masks[i][j]); 6416 } 6417} 6418 6419/* 6420 * Update sched_domains_numa_masks[level][node] array when new cpus 6421 * are onlined. 6422 */ 6423static int sched_domains_numa_masks_update(struct notifier_block *nfb, 6424 unsigned long action, 6425 void *hcpu) 6426{ 6427 int cpu = (long)hcpu; 6428 6429 switch (action & ~CPU_TASKS_FROZEN) { 6430 case CPU_ONLINE: 6431 sched_domains_numa_masks_set(cpu); 6432 break; 6433 6434 case CPU_DEAD: 6435 sched_domains_numa_masks_clear(cpu); 6436 break; 6437 6438 default: 6439 return NOTIFY_DONE; 6440 } 6441 6442 return NOTIFY_OK; 6443} 6444#else 6445static inline void sched_init_numa(void) 6446{ 6447} 6448 6449static int sched_domains_numa_masks_update(struct notifier_block *nfb, 6450 unsigned long action, 6451 void *hcpu) 6452{ 6453 return 0; 6454} 6455#endif /* CONFIG_NUMA */ 6456 6457static int __sdt_alloc(const struct cpumask *cpu_map) 6458{ 6459 struct sched_domain_topology_level *tl; 6460 int j; 6461 6462 for_each_sd_topology(tl) { 6463 struct sd_data *sdd = &tl->data; 6464 6465 sdd->sd = alloc_percpu(struct sched_domain *); 6466 if (!sdd->sd) 6467 return -ENOMEM; 6468 6469 sdd->sg = alloc_percpu(struct sched_group *); 6470 if (!sdd->sg) 6471 return -ENOMEM; 6472 6473 sdd->sgc = alloc_percpu(struct sched_group_capacity *); 6474 if (!sdd->sgc) 6475 return -ENOMEM; 6476 6477 for_each_cpu(j, cpu_map) { 6478 struct sched_domain *sd; 6479 struct sched_group *sg; 6480 struct sched_group_capacity *sgc; 6481 6482 sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(), 6483 GFP_KERNEL, cpu_to_node(j)); 6484 if (!sd) 6485 return -ENOMEM; 6486 6487 *per_cpu_ptr(sdd->sd, j) = sd; 6488 6489 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), 6490 GFP_KERNEL, cpu_to_node(j)); 6491 if (!sg) 6492 return -ENOMEM; 6493 6494 sg->next = sg; 6495 6496 *per_cpu_ptr(sdd->sg, j) = sg; 6497 6498 sgc = kzalloc_node(sizeof(struct sched_group_capacity) + cpumask_size(), 6499 GFP_KERNEL, cpu_to_node(j)); 6500 if (!sgc) 6501 return -ENOMEM; 6502 6503 *per_cpu_ptr(sdd->sgc, j) = sgc; 6504 } 6505 } 6506 6507 return 0; 6508} 6509 6510static void __sdt_free(const struct cpumask *cpu_map) 6511{ 6512 struct sched_domain_topology_level *tl; 6513 int j; 6514 6515 for_each_sd_topology(tl) { 6516 struct sd_data *sdd = &tl->data; 6517 6518 for_each_cpu(j, cpu_map) { 6519 struct sched_domain *sd; 6520 6521 if (sdd->sd) { 6522 sd = *per_cpu_ptr(sdd->sd, j); 6523 if (sd && (sd->flags & SD_OVERLAP)) 6524 free_sched_groups(sd->groups, 0); 6525 kfree(*per_cpu_ptr(sdd->sd, j)); 6526 } 6527 6528 if (sdd->sg) 6529 kfree(*per_cpu_ptr(sdd->sg, j)); 6530 if (sdd->sgc) 6531 kfree(*per_cpu_ptr(sdd->sgc, j)); 6532 } 6533 free_percpu(sdd->sd); 6534 sdd->sd = NULL; 6535 free_percpu(sdd->sg); 6536 sdd->sg = NULL; 6537 free_percpu(sdd->sgc); 6538 sdd->sgc = NULL; 6539 } 6540} 6541 6542struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl, 6543 const struct cpumask *cpu_map, struct sched_domain_attr *attr, 6544 struct sched_domain *child, int cpu) 6545{ 6546 struct sched_domain *sd = sd_init(tl, cpu); 6547 if (!sd) 6548 return child; 6549 6550 cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu)); 6551 if (child) { 6552 sd->level = child->level + 1; 6553 sched_domain_level_max = max(sched_domain_level_max, sd->level); 6554 child->parent = sd; 6555 sd->child = child; 6556 6557 if (!cpumask_subset(sched_domain_span(child), 6558 sched_domain_span(sd))) { 6559 pr_err("BUG: arch topology borken\n"); 6560#ifdef CONFIG_SCHED_DEBUG 6561 pr_err(" the %s domain not a subset of the %s domain\n", 6562 child->name, sd->name); 6563#endif 6564 /* Fixup, ensure @sd has at least @child cpus. */ 6565 cpumask_or(sched_domain_span(sd), 6566 sched_domain_span(sd), 6567 sched_domain_span(child)); 6568 } 6569 6570 } 6571 set_domain_attribute(sd, attr); 6572 6573 return sd; 6574} 6575 6576/* 6577 * Build sched domains for a given set of cpus and attach the sched domains 6578 * to the individual cpus 6579 */ 6580static int build_sched_domains(const struct cpumask *cpu_map, 6581 struct sched_domain_attr *attr) 6582{ 6583 enum s_alloc alloc_state; 6584 struct sched_domain *sd; 6585 struct s_data d; 6586 int i, ret = -ENOMEM; 6587 6588 alloc_state = __visit_domain_allocation_hell(&d, cpu_map); 6589 if (alloc_state != sa_rootdomain) 6590 goto error; 6591 6592 /* Set up domains for cpus specified by the cpu_map. */ 6593 for_each_cpu(i, cpu_map) { 6594 struct sched_domain_topology_level *tl; 6595 6596 sd = NULL; 6597 for_each_sd_topology(tl) { 6598 sd = build_sched_domain(tl, cpu_map, attr, sd, i); 6599 if (tl == sched_domain_topology) 6600 *per_cpu_ptr(d.sd, i) = sd; 6601 if (tl->flags & SDTL_OVERLAP || sched_feat(FORCE_SD_OVERLAP)) 6602 sd->flags |= SD_OVERLAP; 6603 if (cpumask_equal(cpu_map, sched_domain_span(sd))) 6604 break; 6605 } 6606 } 6607 6608 /* Build the groups for the domains */ 6609 for_each_cpu(i, cpu_map) { 6610 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { 6611 sd->span_weight = cpumask_weight(sched_domain_span(sd)); 6612 if (sd->flags & SD_OVERLAP) { 6613 if (build_overlap_sched_groups(sd, i)) 6614 goto error; 6615 } else { 6616 if (build_sched_groups(sd, i)) 6617 goto error; 6618 } 6619 } 6620 } 6621 6622 /* Calculate CPU capacity for physical packages and nodes */ 6623 for (i = nr_cpumask_bits-1; i >= 0; i--) { 6624 if (!cpumask_test_cpu(i, cpu_map)) 6625 continue; 6626 6627 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { 6628 claim_allocations(i, sd); 6629 init_sched_groups_capacity(i, sd); 6630 } 6631 } 6632 6633 /* Attach the domains */ 6634 rcu_read_lock(); 6635 for_each_cpu(i, cpu_map) { 6636 sd = *per_cpu_ptr(d.sd, i); 6637 cpu_attach_domain(sd, d.rd, i); 6638 } 6639 rcu_read_unlock(); 6640 6641 ret = 0; 6642error: 6643 __free_domain_allocs(&d, alloc_state, cpu_map); 6644 return ret; 6645} 6646 6647static cpumask_var_t *doms_cur; /* current sched domains */ 6648static int ndoms_cur; /* number of sched domains in 'doms_cur' */ 6649static struct sched_domain_attr *dattr_cur; 6650 /* attribues of custom domains in 'doms_cur' */ 6651 6652/* 6653 * Special case: If a kmalloc of a doms_cur partition (array of 6654 * cpumask) fails, then fallback to a single sched domain, 6655 * as determined by the single cpumask fallback_doms. 6656 */ 6657static cpumask_var_t fallback_doms; 6658 6659/* 6660 * arch_update_cpu_topology lets virtualized architectures update the 6661 * cpu core maps. It is supposed to return 1 if the topology changed 6662 * or 0 if it stayed the same. 6663 */ 6664int __weak arch_update_cpu_topology(void) 6665{ 6666 return 0; 6667} 6668 6669cpumask_var_t *alloc_sched_domains(unsigned int ndoms) 6670{ 6671 int i; 6672 cpumask_var_t *doms; 6673 6674 doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL); 6675 if (!doms) 6676 return NULL; 6677 for (i = 0; i < ndoms; i++) { 6678 if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) { 6679 free_sched_domains(doms, i); 6680 return NULL; 6681 } 6682 } 6683 return doms; 6684} 6685 6686void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms) 6687{ 6688 unsigned int i; 6689 for (i = 0; i < ndoms; i++) 6690 free_cpumask_var(doms[i]); 6691 kfree(doms); 6692} 6693 6694/* 6695 * Set up scheduler domains and groups. Callers must hold the hotplug lock. 6696 * For now this just excludes isolated cpus, but could be used to 6697 * exclude other special cases in the future. 6698 */ 6699static int init_sched_domains(const struct cpumask *cpu_map) 6700{ 6701 int err; 6702 6703 arch_update_cpu_topology(); 6704 ndoms_cur = 1; 6705 doms_cur = alloc_sched_domains(ndoms_cur); 6706 if (!doms_cur) 6707 doms_cur = &fallback_doms; 6708 cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map); 6709 err = build_sched_domains(doms_cur[0], NULL); 6710 register_sched_domain_sysctl(); 6711 6712 return err; 6713} 6714 6715/* 6716 * Detach sched domains from a group of cpus specified in cpu_map 6717 * These cpus will now be attached to the NULL domain 6718 */ 6719static void detach_destroy_domains(const struct cpumask *cpu_map) 6720{ 6721 int i; 6722 6723 rcu_read_lock(); 6724 for_each_cpu(i, cpu_map) 6725 cpu_attach_domain(NULL, &def_root_domain, i); 6726 rcu_read_unlock(); 6727} 6728 6729/* handle null as "default" */ 6730static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur, 6731 struct sched_domain_attr *new, int idx_new) 6732{ 6733 struct sched_domain_attr tmp; 6734 6735 /* fast path */ 6736 if (!new && !cur) 6737 return 1; 6738 6739 tmp = SD_ATTR_INIT; 6740 return !memcmp(cur ? (cur + idx_cur) : &tmp, 6741 new ? (new + idx_new) : &tmp, 6742 sizeof(struct sched_domain_attr)); 6743} 6744 6745/* 6746 * Partition sched domains as specified by the 'ndoms_new' 6747 * cpumasks in the array doms_new[] of cpumasks. This compares 6748 * doms_new[] to the current sched domain partitioning, doms_cur[]. 6749 * It destroys each deleted domain and builds each new domain. 6750 * 6751 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'. 6752 * The masks don't intersect (don't overlap.) We should setup one 6753 * sched domain for each mask. CPUs not in any of the cpumasks will 6754 * not be load balanced. If the same cpumask appears both in the 6755 * current 'doms_cur' domains and in the new 'doms_new', we can leave 6756 * it as it is. 6757 * 6758 * The passed in 'doms_new' should be allocated using 6759 * alloc_sched_domains. This routine takes ownership of it and will 6760 * free_sched_domains it when done with it. If the caller failed the 6761 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1, 6762 * and partition_sched_domains() will fallback to the single partition 6763 * 'fallback_doms', it also forces the domains to be rebuilt. 6764 * 6765 * If doms_new == NULL it will be replaced with cpu_online_mask. 6766 * ndoms_new == 0 is a special case for destroying existing domains, 6767 * and it will not create the default domain. 6768 * 6769 * Call with hotplug lock held 6770 */ 6771void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[], 6772 struct sched_domain_attr *dattr_new) 6773{ 6774 int i, j, n; 6775 int new_topology; 6776 6777 mutex_lock(&sched_domains_mutex); 6778 6779 /* always unregister in case we don't destroy any domains */ 6780 unregister_sched_domain_sysctl(); 6781 6782 /* Let architecture update cpu core mappings. */ 6783 new_topology = arch_update_cpu_topology(); 6784 6785 n = doms_new ? ndoms_new : 0; 6786 6787 /* Destroy deleted domains */ 6788 for (i = 0; i < ndoms_cur; i++) { 6789 for (j = 0; j < n && !new_topology; j++) { 6790 if (cpumask_equal(doms_cur[i], doms_new[j]) 6791 && dattrs_equal(dattr_cur, i, dattr_new, j)) 6792 goto match1; 6793 } 6794 /* no match - a current sched domain not in new doms_new[] */ 6795 detach_destroy_domains(doms_cur[i]); 6796match1: 6797 ; 6798 } 6799 6800 n = ndoms_cur; 6801 if (doms_new == NULL) { 6802 n = 0; 6803 doms_new = &fallback_doms; 6804 cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map); 6805 WARN_ON_ONCE(dattr_new); 6806 } 6807 6808 /* Build new domains */ 6809 for (i = 0; i < ndoms_new; i++) { 6810 for (j = 0; j < n && !new_topology; j++) { 6811 if (cpumask_equal(doms_new[i], doms_cur[j]) 6812 && dattrs_equal(dattr_new, i, dattr_cur, j)) 6813 goto match2; 6814 } 6815 /* no match - add a new doms_new */ 6816 build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL); 6817match2: 6818 ; 6819 } 6820 6821 /* Remember the new sched domains */ 6822 if (doms_cur != &fallback_doms) 6823 free_sched_domains(doms_cur, ndoms_cur); 6824 kfree(dattr_cur); /* kfree(NULL) is safe */ 6825 doms_cur = doms_new; 6826 dattr_cur = dattr_new; 6827 ndoms_cur = ndoms_new; 6828 6829 register_sched_domain_sysctl(); 6830 6831 mutex_unlock(&sched_domains_mutex); 6832} 6833 6834static int num_cpus_frozen; /* used to mark begin/end of suspend/resume */ 6835 6836/* 6837 * Update cpusets according to cpu_active mask. If cpusets are 6838 * disabled, cpuset_update_active_cpus() becomes a simple wrapper 6839 * around partition_sched_domains(). 6840 * 6841 * If we come here as part of a suspend/resume, don't touch cpusets because we 6842 * want to restore it back to its original state upon resume anyway. 6843 */ 6844static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action, 6845 void *hcpu) 6846{ 6847 switch (action) { 6848 case CPU_ONLINE_FROZEN: 6849 case CPU_DOWN_FAILED_FROZEN: 6850 6851 /* 6852 * num_cpus_frozen tracks how many CPUs are involved in suspend 6853 * resume sequence. As long as this is not the last online 6854 * operation in the resume sequence, just build a single sched 6855 * domain, ignoring cpusets. 6856 */ 6857 num_cpus_frozen--; 6858 if (likely(num_cpus_frozen)) { 6859 partition_sched_domains(1, NULL, NULL); 6860 break; 6861 } 6862 6863 /* 6864 * This is the last CPU online operation. So fall through and 6865 * restore the original sched domains by considering the 6866 * cpuset configurations. 6867 */ 6868 6869 case CPU_ONLINE: 6870 case CPU_DOWN_FAILED: 6871 cpuset_update_active_cpus(true); 6872 break; 6873 default: 6874 return NOTIFY_DONE; 6875 } 6876 return NOTIFY_OK; 6877} 6878 6879static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action, 6880 void *hcpu) 6881{ 6882 switch (action) { 6883 case CPU_DOWN_PREPARE: 6884 cpuset_update_active_cpus(false); 6885 break; 6886 case CPU_DOWN_PREPARE_FROZEN: 6887 num_cpus_frozen++; 6888 partition_sched_domains(1, NULL, NULL); 6889 break; 6890 default: 6891 return NOTIFY_DONE; 6892 } 6893 return NOTIFY_OK; 6894} 6895 6896void __init sched_init_smp(void) 6897{ 6898 cpumask_var_t non_isolated_cpus; 6899 6900 alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL); 6901 alloc_cpumask_var(&fallback_doms, GFP_KERNEL); 6902 6903 sched_init_numa(); 6904 6905 /* 6906 * There's no userspace yet to cause hotplug operations; hence all the 6907 * cpu masks are stable and all blatant races in the below code cannot 6908 * happen. 6909 */ 6910 mutex_lock(&sched_domains_mutex); 6911 init_sched_domains(cpu_active_mask); 6912 cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map); 6913 if (cpumask_empty(non_isolated_cpus)) 6914 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus); 6915 mutex_unlock(&sched_domains_mutex); 6916 6917 hotcpu_notifier(sched_domains_numa_masks_update, CPU_PRI_SCHED_ACTIVE); 6918 hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE); 6919 hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE); 6920 6921 init_hrtick(); 6922 6923 /* Move init over to a non-isolated CPU */ 6924 if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0) 6925 BUG(); 6926 sched_init_granularity(); 6927 free_cpumask_var(non_isolated_cpus); 6928 6929 init_sched_rt_class(); 6930 init_sched_dl_class(); 6931} 6932#else 6933void __init sched_init_smp(void) 6934{ 6935 sched_init_granularity(); 6936} 6937#endif /* CONFIG_SMP */ 6938 6939const_debug unsigned int sysctl_timer_migration = 1; 6940 6941int in_sched_functions(unsigned long addr) 6942{ 6943 return in_lock_functions(addr) || 6944 (addr >= (unsigned long)__sched_text_start 6945 && addr < (unsigned long)__sched_text_end); 6946} 6947 6948#ifdef CONFIG_CGROUP_SCHED 6949/* 6950 * Default task group. 6951 * Every task in system belongs to this group at bootup. 6952 */ 6953struct task_group root_task_group; 6954LIST_HEAD(task_groups); 6955#endif 6956 6957DECLARE_PER_CPU(cpumask_var_t, load_balance_mask); 6958 6959void __init sched_init(void) 6960{ 6961 int i, j; 6962 unsigned long alloc_size = 0, ptr; 6963 6964#ifdef CONFIG_FAIR_GROUP_SCHED 6965 alloc_size += 2 * nr_cpu_ids * sizeof(void **); 6966#endif 6967#ifdef CONFIG_RT_GROUP_SCHED 6968 alloc_size += 2 * nr_cpu_ids * sizeof(void **); 6969#endif 6970#ifdef CONFIG_CPUMASK_OFFSTACK 6971 alloc_size += num_possible_cpus() * cpumask_size(); 6972#endif 6973 if (alloc_size) { 6974 ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT); 6975 6976#ifdef CONFIG_FAIR_GROUP_SCHED 6977 root_task_group.se = (struct sched_entity **)ptr; 6978 ptr += nr_cpu_ids * sizeof(void **); 6979 6980 root_task_group.cfs_rq = (struct cfs_rq **)ptr; 6981 ptr += nr_cpu_ids * sizeof(void **); 6982 6983#endif /* CONFIG_FAIR_GROUP_SCHED */ 6984#ifdef CONFIG_RT_GROUP_SCHED 6985 root_task_group.rt_se = (struct sched_rt_entity **)ptr; 6986 ptr += nr_cpu_ids * sizeof(void **); 6987 6988 root_task_group.rt_rq = (struct rt_rq **)ptr; 6989 ptr += nr_cpu_ids * sizeof(void **); 6990 6991#endif /* CONFIG_RT_GROUP_SCHED */ 6992#ifdef CONFIG_CPUMASK_OFFSTACK 6993 for_each_possible_cpu(i) { 6994 per_cpu(load_balance_mask, i) = (void *)ptr; 6995 ptr += cpumask_size(); 6996 } 6997#endif /* CONFIG_CPUMASK_OFFSTACK */ 6998 } 6999 7000 init_rt_bandwidth(&def_rt_bandwidth, 7001 global_rt_period(), global_rt_runtime()); 7002 init_dl_bandwidth(&def_dl_bandwidth, 7003 global_rt_period(), global_rt_runtime()); 7004 7005#ifdef CONFIG_SMP 7006 init_defrootdomain(); 7007#endif 7008 7009#ifdef CONFIG_RT_GROUP_SCHED 7010 init_rt_bandwidth(&root_task_group.rt_bandwidth, 7011 global_rt_period(), global_rt_runtime()); 7012#endif /* CONFIG_RT_GROUP_SCHED */ 7013 7014#ifdef CONFIG_CGROUP_SCHED 7015 list_add(&root_task_group.list, &task_groups); 7016 INIT_LIST_HEAD(&root_task_group.children); 7017 INIT_LIST_HEAD(&root_task_group.siblings); 7018 autogroup_init(&init_task); 7019 7020#endif /* CONFIG_CGROUP_SCHED */ 7021 7022 for_each_possible_cpu(i) { 7023 struct rq *rq; 7024 7025 rq = cpu_rq(i); 7026 raw_spin_lock_init(&rq->lock); 7027 rq->nr_running = 0; 7028 rq->calc_load_active = 0; 7029 rq->calc_load_update = jiffies + LOAD_FREQ; 7030 init_cfs_rq(&rq->cfs); 7031 init_rt_rq(&rq->rt, rq); 7032 init_dl_rq(&rq->dl, rq); 7033#ifdef CONFIG_FAIR_GROUP_SCHED 7034 root_task_group.shares = ROOT_TASK_GROUP_LOAD; 7035 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list); 7036 /* 7037 * How much cpu bandwidth does root_task_group get? 7038 * 7039 * In case of task-groups formed thr' the cgroup filesystem, it 7040 * gets 100% of the cpu resources in the system. This overall 7041 * system cpu resource is divided among the tasks of 7042 * root_task_group and its child task-groups in a fair manner, 7043 * based on each entity's (task or task-group's) weight 7044 * (se->load.weight). 7045 * 7046 * In other words, if root_task_group has 10 tasks of weight 7047 * 1024) and two child groups A0 and A1 (of weight 1024 each), 7048 * then A0's share of the cpu resource is: 7049 * 7050 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33% 7051 * 7052 * We achieve this by letting root_task_group's tasks sit 7053 * directly in rq->cfs (i.e root_task_group->se[] = NULL). 7054 */ 7055 init_cfs_bandwidth(&root_task_group.cfs_bandwidth); 7056 init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL); 7057#endif /* CONFIG_FAIR_GROUP_SCHED */ 7058 7059 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime; 7060#ifdef CONFIG_RT_GROUP_SCHED 7061 init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL); 7062#endif 7063 7064 for (j = 0; j < CPU_LOAD_IDX_MAX; j++) 7065 rq->cpu_load[j] = 0; 7066 7067 rq->last_load_update_tick = jiffies; 7068 7069#ifdef CONFIG_SMP 7070 rq->sd = NULL; 7071 rq->rd = NULL; 7072 rq->cpu_capacity = SCHED_CAPACITY_SCALE; 7073 rq->post_schedule = 0; 7074 rq->active_balance = 0; 7075 rq->next_balance = jiffies; 7076 rq->push_cpu = 0; 7077 rq->cpu = i; 7078 rq->online = 0; 7079 rq->idle_stamp = 0; 7080 rq->avg_idle = 2*sysctl_sched_migration_cost; 7081 rq->max_idle_balance_cost = sysctl_sched_migration_cost; 7082 7083 INIT_LIST_HEAD(&rq->cfs_tasks); 7084 7085 rq_attach_root(rq, &def_root_domain); 7086#ifdef CONFIG_NO_HZ_COMMON 7087 rq->nohz_flags = 0; 7088#endif 7089#ifdef CONFIG_NO_HZ_FULL 7090 rq->last_sched_tick = 0; 7091#endif 7092#endif 7093 init_rq_hrtick(rq); 7094 atomic_set(&rq->nr_iowait, 0); 7095 } 7096 7097 set_load_weight(&init_task); 7098 7099#ifdef CONFIG_PREEMPT_NOTIFIERS 7100 INIT_HLIST_HEAD(&init_task.preempt_notifiers); 7101#endif 7102 7103 /* 7104 * The boot idle thread does lazy MMU switching as well: 7105 */ 7106 atomic_inc(&init_mm.mm_count); 7107 enter_lazy_tlb(&init_mm, current); 7108 7109 /* 7110 * Make us the idle thread. Technically, schedule() should not be 7111 * called from this thread, however somewhere below it might be, 7112 * but because we are the idle thread, we just pick up running again 7113 * when this runqueue becomes "idle". 7114 */ 7115 init_idle(current, smp_processor_id()); 7116 7117 calc_load_update = jiffies + LOAD_FREQ; 7118 7119 /* 7120 * During early bootup we pretend to be a normal task: 7121 */ 7122 current->sched_class = &fair_sched_class; 7123 7124#ifdef CONFIG_SMP 7125 zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT); 7126 /* May be allocated at isolcpus cmdline parse time */ 7127 if (cpu_isolated_map == NULL) 7128 zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT); 7129 idle_thread_set_boot_cpu(); 7130 set_cpu_rq_start_time(); 7131#endif 7132 init_sched_fair_class(); 7133 7134 scheduler_running = 1; 7135} 7136 7137#ifdef CONFIG_DEBUG_ATOMIC_SLEEP 7138static inline int preempt_count_equals(int preempt_offset) 7139{ 7140 int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth(); 7141 7142 return (nested == preempt_offset); 7143} 7144 7145void __might_sleep(const char *file, int line, int preempt_offset) 7146{ 7147 static unsigned long prev_jiffy; /* ratelimiting */ 7148 7149 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */ 7150 if ((preempt_count_equals(preempt_offset) && !irqs_disabled() && 7151 !is_idle_task(current)) || 7152 system_state != SYSTEM_RUNNING || oops_in_progress) 7153 return; 7154 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) 7155 return; 7156 prev_jiffy = jiffies; 7157 7158 printk(KERN_ERR 7159 "BUG: sleeping function called from invalid context at %s:%d\n", 7160 file, line); 7161 printk(KERN_ERR 7162 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n", 7163 in_atomic(), irqs_disabled(), 7164 current->pid, current->comm); 7165 7166 debug_show_held_locks(current); 7167 if (irqs_disabled()) 7168 print_irqtrace_events(current); 7169#ifdef CONFIG_DEBUG_PREEMPT 7170 if (!preempt_count_equals(preempt_offset)) { 7171 pr_err("Preemption disabled at:"); 7172 print_ip_sym(current->preempt_disable_ip); 7173 pr_cont("\n"); 7174 } 7175#endif 7176 dump_stack(); 7177} 7178EXPORT_SYMBOL(__might_sleep); 7179#endif 7180 7181#ifdef CONFIG_MAGIC_SYSRQ 7182static void normalize_task(struct rq *rq, struct task_struct *p) 7183{ 7184 const struct sched_class *prev_class = p->sched_class; 7185 struct sched_attr attr = { 7186 .sched_policy = SCHED_NORMAL, 7187 }; 7188 int old_prio = p->prio; 7189 int queued; 7190 7191 queued = task_on_rq_queued(p); 7192 if (queued) 7193 dequeue_task(rq, p, 0); 7194 __setscheduler(rq, p, &attr); 7195 if (queued) { 7196 enqueue_task(rq, p, 0); 7197 resched_curr(rq); 7198 } 7199 7200 check_class_changed(rq, p, prev_class, old_prio); 7201} 7202 7203void normalize_rt_tasks(void) 7204{ 7205 struct task_struct *g, *p; 7206 unsigned long flags; 7207 struct rq *rq; 7208 7209 read_lock_irqsave(&tasklist_lock, flags); 7210 for_each_process_thread(g, p) { 7211 /* 7212 * Only normalize user tasks: 7213 */ 7214 if (!p->mm) 7215 continue; 7216 7217 p->se.exec_start = 0; 7218#ifdef CONFIG_SCHEDSTATS 7219 p->se.statistics.wait_start = 0; 7220 p->se.statistics.sleep_start = 0; 7221 p->se.statistics.block_start = 0; 7222#endif 7223 7224 if (!dl_task(p) && !rt_task(p)) { 7225 /* 7226 * Renice negative nice level userspace 7227 * tasks back to 0: 7228 */ 7229 if (task_nice(p) < 0 && p->mm) 7230 set_user_nice(p, 0); 7231 continue; 7232 } 7233 7234 raw_spin_lock(&p->pi_lock); 7235 rq = __task_rq_lock(p); 7236 7237 normalize_task(rq, p); 7238 7239 __task_rq_unlock(rq); 7240 raw_spin_unlock(&p->pi_lock); 7241 } 7242 read_unlock_irqrestore(&tasklist_lock, flags); 7243} 7244 7245#endif /* CONFIG_MAGIC_SYSRQ */ 7246 7247#if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) 7248/* 7249 * These functions are only useful for the IA64 MCA handling, or kdb. 7250 * 7251 * They can only be called when the whole system has been 7252 * stopped - every CPU needs to be quiescent, and no scheduling 7253 * activity can take place. Using them for anything else would 7254 * be a serious bug, and as a result, they aren't even visible 7255 * under any other configuration. 7256 */ 7257 7258/** 7259 * curr_task - return the current task for a given cpu. 7260 * @cpu: the processor in question. 7261 * 7262 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! 7263 * 7264 * Return: The current task for @cpu. 7265 */ 7266struct task_struct *curr_task(int cpu) 7267{ 7268 return cpu_curr(cpu); 7269} 7270 7271#endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */ 7272 7273#ifdef CONFIG_IA64 7274/** 7275 * set_curr_task - set the current task for a given cpu. 7276 * @cpu: the processor in question. 7277 * @p: the task pointer to set. 7278 * 7279 * Description: This function must only be used when non-maskable interrupts 7280 * are serviced on a separate stack. It allows the architecture to switch the 7281 * notion of the current task on a cpu in a non-blocking manner. This function 7282 * must be called with all CPU's synchronized, and interrupts disabled, the 7283 * and caller must save the original value of the current task (see 7284 * curr_task() above) and restore that value before reenabling interrupts and 7285 * re-starting the system. 7286 * 7287 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! 7288 */ 7289void set_curr_task(int cpu, struct task_struct *p) 7290{ 7291 cpu_curr(cpu) = p; 7292} 7293 7294#endif 7295 7296#ifdef CONFIG_CGROUP_SCHED 7297/* task_group_lock serializes the addition/removal of task groups */ 7298static DEFINE_SPINLOCK(task_group_lock); 7299 7300static void free_sched_group(struct task_group *tg) 7301{ 7302 free_fair_sched_group(tg); 7303 free_rt_sched_group(tg); 7304 autogroup_free(tg); 7305 kfree(tg); 7306} 7307 7308/* allocate runqueue etc for a new task group */ 7309struct task_group *sched_create_group(struct task_group *parent) 7310{ 7311 struct task_group *tg; 7312 7313 tg = kzalloc(sizeof(*tg), GFP_KERNEL); 7314 if (!tg) 7315 return ERR_PTR(-ENOMEM); 7316 7317 if (!alloc_fair_sched_group(tg, parent)) 7318 goto err; 7319 7320 if (!alloc_rt_sched_group(tg, parent)) 7321 goto err; 7322 7323 return tg; 7324 7325err: 7326 free_sched_group(tg); 7327 return ERR_PTR(-ENOMEM); 7328} 7329 7330void sched_online_group(struct task_group *tg, struct task_group *parent) 7331{ 7332 unsigned long flags; 7333 7334 spin_lock_irqsave(&task_group_lock, flags); 7335 list_add_rcu(&tg->list, &task_groups); 7336 7337 WARN_ON(!parent); /* root should already exist */ 7338 7339 tg->parent = parent; 7340 INIT_LIST_HEAD(&tg->children); 7341 list_add_rcu(&tg->siblings, &parent->children); 7342 spin_unlock_irqrestore(&task_group_lock, flags); 7343} 7344 7345/* rcu callback to free various structures associated with a task group */ 7346static void free_sched_group_rcu(struct rcu_head *rhp) 7347{ 7348 /* now it should be safe to free those cfs_rqs */ 7349 free_sched_group(container_of(rhp, struct task_group, rcu)); 7350} 7351 7352/* Destroy runqueue etc associated with a task group */ 7353void sched_destroy_group(struct task_group *tg) 7354{ 7355 /* wait for possible concurrent references to cfs_rqs complete */ 7356 call_rcu(&tg->rcu, free_sched_group_rcu); 7357} 7358 7359void sched_offline_group(struct task_group *tg) 7360{ 7361 unsigned long flags; 7362 int i; 7363 7364 /* end participation in shares distribution */ 7365 for_each_possible_cpu(i) 7366 unregister_fair_sched_group(tg, i); 7367 7368 spin_lock_irqsave(&task_group_lock, flags); 7369 list_del_rcu(&tg->list); 7370 list_del_rcu(&tg->siblings); 7371 spin_unlock_irqrestore(&task_group_lock, flags); 7372} 7373 7374/* change task's runqueue when it moves between groups. 7375 * The caller of this function should have put the task in its new group 7376 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to 7377 * reflect its new group. 7378 */ 7379void sched_move_task(struct task_struct *tsk) 7380{ 7381 struct task_group *tg; 7382 int queued, running; 7383 unsigned long flags; 7384 struct rq *rq; 7385 7386 rq = task_rq_lock(tsk, &flags); 7387 7388 running = task_current(rq, tsk); 7389 queued = task_on_rq_queued(tsk); 7390 7391 if (queued) 7392 dequeue_task(rq, tsk, 0); 7393 if (unlikely(running)) 7394 put_prev_task(rq, tsk); 7395 7396 tg = container_of(task_css_check(tsk, cpu_cgrp_id, 7397 lockdep_is_held(&tsk->sighand->siglock)), 7398 struct task_group, css); 7399 tg = autogroup_task_group(tsk, tg); 7400 tsk->sched_task_group = tg; 7401 7402#ifdef CONFIG_FAIR_GROUP_SCHED 7403 if (tsk->sched_class->task_move_group) 7404 tsk->sched_class->task_move_group(tsk, queued); 7405 else 7406#endif 7407 set_task_rq(tsk, task_cpu(tsk)); 7408 7409 if (unlikely(running)) 7410 tsk->sched_class->set_curr_task(rq); 7411 if (queued) 7412 enqueue_task(rq, tsk, 0); 7413 7414 task_rq_unlock(rq, tsk, &flags); 7415} 7416#endif /* CONFIG_CGROUP_SCHED */ 7417 7418#ifdef CONFIG_RT_GROUP_SCHED 7419/* 7420 * Ensure that the real time constraints are schedulable. 7421 */ 7422static DEFINE_MUTEX(rt_constraints_mutex); 7423 7424/* Must be called with tasklist_lock held */ 7425static inline int tg_has_rt_tasks(struct task_group *tg) 7426{ 7427 struct task_struct *g, *p; 7428 7429 for_each_process_thread(g, p) { 7430 if (rt_task(p) && task_rq(p)->rt.tg == tg) 7431 return 1; 7432 } 7433 7434 return 0; 7435} 7436 7437struct rt_schedulable_data { 7438 struct task_group *tg; 7439 u64 rt_period; 7440 u64 rt_runtime; 7441}; 7442 7443static int tg_rt_schedulable(struct task_group *tg, void *data) 7444{ 7445 struct rt_schedulable_data *d = data; 7446 struct task_group *child; 7447 unsigned long total, sum = 0; 7448 u64 period, runtime; 7449 7450 period = ktime_to_ns(tg->rt_bandwidth.rt_period); 7451 runtime = tg->rt_bandwidth.rt_runtime; 7452 7453 if (tg == d->tg) { 7454 period = d->rt_period; 7455 runtime = d->rt_runtime; 7456 } 7457 7458 /* 7459 * Cannot have more runtime than the period. 7460 */ 7461 if (runtime > period && runtime != RUNTIME_INF) 7462 return -EINVAL; 7463 7464 /* 7465 * Ensure we don't starve existing RT tasks. 7466 */ 7467 if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg)) 7468 return -EBUSY; 7469 7470 total = to_ratio(period, runtime); 7471 7472 /* 7473 * Nobody can have more than the global setting allows. 7474 */ 7475 if (total > to_ratio(global_rt_period(), global_rt_runtime())) 7476 return -EINVAL; 7477 7478 /* 7479 * The sum of our children's runtime should not exceed our own. 7480 */ 7481 list_for_each_entry_rcu(child, &tg->children, siblings) { 7482 period = ktime_to_ns(child->rt_bandwidth.rt_period); 7483 runtime = child->rt_bandwidth.rt_runtime; 7484 7485 if (child == d->tg) { 7486 period = d->rt_period; 7487 runtime = d->rt_runtime; 7488 } 7489 7490 sum += to_ratio(period, runtime); 7491 } 7492 7493 if (sum > total) 7494 return -EINVAL; 7495 7496 return 0; 7497} 7498 7499static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime) 7500{ 7501 int ret; 7502 7503 struct rt_schedulable_data data = { 7504 .tg = tg, 7505 .rt_period = period, 7506 .rt_runtime = runtime, 7507 }; 7508 7509 rcu_read_lock(); 7510 ret = walk_tg_tree(tg_rt_schedulable, tg_nop, &data); 7511 rcu_read_unlock(); 7512 7513 return ret; 7514} 7515 7516static int tg_set_rt_bandwidth(struct task_group *tg, 7517 u64 rt_period, u64 rt_runtime) 7518{ 7519 int i, err = 0; 7520 7521 mutex_lock(&rt_constraints_mutex); 7522 read_lock(&tasklist_lock); 7523 err = __rt_schedulable(tg, rt_period, rt_runtime); 7524 if (err) 7525 goto unlock; 7526 7527 raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock); 7528 tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period); 7529 tg->rt_bandwidth.rt_runtime = rt_runtime; 7530 7531 for_each_possible_cpu(i) { 7532 struct rt_rq *rt_rq = tg->rt_rq[i]; 7533 7534 raw_spin_lock(&rt_rq->rt_runtime_lock); 7535 rt_rq->rt_runtime = rt_runtime; 7536 raw_spin_unlock(&rt_rq->rt_runtime_lock); 7537 } 7538 raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock); 7539unlock: 7540 read_unlock(&tasklist_lock); 7541 mutex_unlock(&rt_constraints_mutex); 7542 7543 return err; 7544} 7545 7546static int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us) 7547{ 7548 u64 rt_runtime, rt_period; 7549 7550 rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period); 7551 rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC; 7552 if (rt_runtime_us < 0) 7553 rt_runtime = RUNTIME_INF; 7554 7555 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); 7556} 7557 7558static long sched_group_rt_runtime(struct task_group *tg) 7559{ 7560 u64 rt_runtime_us; 7561 7562 if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF) 7563 return -1; 7564 7565 rt_runtime_us = tg->rt_bandwidth.rt_runtime; 7566 do_div(rt_runtime_us, NSEC_PER_USEC); 7567 return rt_runtime_us; 7568} 7569 7570static int sched_group_set_rt_period(struct task_group *tg, long rt_period_us) 7571{ 7572 u64 rt_runtime, rt_period; 7573 7574 rt_period = (u64)rt_period_us * NSEC_PER_USEC; 7575 rt_runtime = tg->rt_bandwidth.rt_runtime; 7576 7577 if (rt_period == 0) 7578 return -EINVAL; 7579 7580 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); 7581} 7582 7583static long sched_group_rt_period(struct task_group *tg) 7584{ 7585 u64 rt_period_us; 7586 7587 rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period); 7588 do_div(rt_period_us, NSEC_PER_USEC); 7589 return rt_period_us; 7590} 7591#endif /* CONFIG_RT_GROUP_SCHED */ 7592 7593#ifdef CONFIG_RT_GROUP_SCHED 7594static int sched_rt_global_constraints(void) 7595{ 7596 int ret = 0; 7597 7598 mutex_lock(&rt_constraints_mutex); 7599 read_lock(&tasklist_lock); 7600 ret = __rt_schedulable(NULL, 0, 0); 7601 read_unlock(&tasklist_lock); 7602 mutex_unlock(&rt_constraints_mutex); 7603 7604 return ret; 7605} 7606 7607static int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk) 7608{ 7609 /* Don't accept realtime tasks when there is no way for them to run */ 7610 if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0) 7611 return 0; 7612 7613 return 1; 7614} 7615 7616#else /* !CONFIG_RT_GROUP_SCHED */ 7617static int sched_rt_global_constraints(void) 7618{ 7619 unsigned long flags; 7620 int i, ret = 0; 7621 7622 raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags); 7623 for_each_possible_cpu(i) { 7624 struct rt_rq *rt_rq = &cpu_rq(i)->rt; 7625 7626 raw_spin_lock(&rt_rq->rt_runtime_lock); 7627 rt_rq->rt_runtime = global_rt_runtime(); 7628 raw_spin_unlock(&rt_rq->rt_runtime_lock); 7629 } 7630 raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags); 7631 7632 return ret; 7633} 7634#endif /* CONFIG_RT_GROUP_SCHED */ 7635 7636static int sched_dl_global_constraints(void) 7637{ 7638 u64 runtime = global_rt_runtime(); 7639 u64 period = global_rt_period(); 7640 u64 new_bw = to_ratio(period, runtime); 7641 int cpu, ret = 0; 7642 unsigned long flags; 7643 7644 /* 7645 * Here we want to check the bandwidth not being set to some 7646 * value smaller than the currently allocated bandwidth in 7647 * any of the root_domains. 7648 * 7649 * FIXME: Cycling on all the CPUs is overdoing, but simpler than 7650 * cycling on root_domains... Discussion on different/better 7651 * solutions is welcome! 7652 */ 7653 for_each_possible_cpu(cpu) { 7654 struct dl_bw *dl_b = dl_bw_of(cpu); 7655 7656 raw_spin_lock_irqsave(&dl_b->lock, flags); 7657 if (new_bw < dl_b->total_bw) 7658 ret = -EBUSY; 7659 raw_spin_unlock_irqrestore(&dl_b->lock, flags); 7660 7661 if (ret) 7662 break; 7663 } 7664 7665 return ret; 7666} 7667 7668static void sched_dl_do_global(void) 7669{ 7670 u64 new_bw = -1; 7671 int cpu; 7672 unsigned long flags; 7673 7674 def_dl_bandwidth.dl_period = global_rt_period(); 7675 def_dl_bandwidth.dl_runtime = global_rt_runtime(); 7676 7677 if (global_rt_runtime() != RUNTIME_INF) 7678 new_bw = to_ratio(global_rt_period(), global_rt_runtime()); 7679 7680 /* 7681 * FIXME: As above... 7682 */ 7683 for_each_possible_cpu(cpu) { 7684 struct dl_bw *dl_b = dl_bw_of(cpu); 7685 7686 raw_spin_lock_irqsave(&dl_b->lock, flags); 7687 dl_b->bw = new_bw; 7688 raw_spin_unlock_irqrestore(&dl_b->lock, flags); 7689 } 7690} 7691 7692static int sched_rt_global_validate(void) 7693{ 7694 if (sysctl_sched_rt_period <= 0) 7695 return -EINVAL; 7696 7697 if ((sysctl_sched_rt_runtime != RUNTIME_INF) && 7698 (sysctl_sched_rt_runtime > sysctl_sched_rt_period)) 7699 return -EINVAL; 7700 7701 return 0; 7702} 7703 7704static void sched_rt_do_global(void) 7705{ 7706 def_rt_bandwidth.rt_runtime = global_rt_runtime(); 7707 def_rt_bandwidth.rt_period = ns_to_ktime(global_rt_period()); 7708} 7709 7710int sched_rt_handler(struct ctl_table *table, int write, 7711 void __user *buffer, size_t *lenp, 7712 loff_t *ppos) 7713{ 7714 int old_period, old_runtime; 7715 static DEFINE_MUTEX(mutex); 7716 int ret; 7717 7718 mutex_lock(&mutex); 7719 old_period = sysctl_sched_rt_period; 7720 old_runtime = sysctl_sched_rt_runtime; 7721 7722 ret = proc_dointvec(table, write, buffer, lenp, ppos); 7723 7724 if (!ret && write) { 7725 ret = sched_rt_global_validate(); 7726 if (ret) 7727 goto undo; 7728 7729 ret = sched_rt_global_constraints(); 7730 if (ret) 7731 goto undo; 7732 7733 ret = sched_dl_global_constraints(); 7734 if (ret) 7735 goto undo; 7736 7737 sched_rt_do_global(); 7738 sched_dl_do_global(); 7739 } 7740 if (0) { 7741undo: 7742 sysctl_sched_rt_period = old_period; 7743 sysctl_sched_rt_runtime = old_runtime; 7744 } 7745 mutex_unlock(&mutex); 7746 7747 return ret; 7748} 7749 7750int sched_rr_handler(struct ctl_table *table, int write, 7751 void __user *buffer, size_t *lenp, 7752 loff_t *ppos) 7753{ 7754 int ret; 7755 static DEFINE_MUTEX(mutex); 7756 7757 mutex_lock(&mutex); 7758 ret = proc_dointvec(table, write, buffer, lenp, ppos); 7759 /* make sure that internally we keep jiffies */ 7760 /* also, writing zero resets timeslice to default */ 7761 if (!ret && write) { 7762 sched_rr_timeslice = sched_rr_timeslice <= 0 ? 7763 RR_TIMESLICE : msecs_to_jiffies(sched_rr_timeslice); 7764 } 7765 mutex_unlock(&mutex); 7766 return ret; 7767} 7768 7769#ifdef CONFIG_CGROUP_SCHED 7770 7771static inline struct task_group *css_tg(struct cgroup_subsys_state *css) 7772{ 7773 return css ? container_of(css, struct task_group, css) : NULL; 7774} 7775 7776static struct cgroup_subsys_state * 7777cpu_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) 7778{ 7779 struct task_group *parent = css_tg(parent_css); 7780 struct task_group *tg; 7781 7782 if (!parent) { 7783 /* This is early initialization for the top cgroup */ 7784 return &root_task_group.css; 7785 } 7786 7787 tg = sched_create_group(parent); 7788 if (IS_ERR(tg)) 7789 return ERR_PTR(-ENOMEM); 7790 7791 return &tg->css; 7792} 7793 7794static int cpu_cgroup_css_online(struct cgroup_subsys_state *css) 7795{ 7796 struct task_group *tg = css_tg(css); 7797 struct task_group *parent = css_tg(css->parent); 7798 7799 if (parent) 7800 sched_online_group(tg, parent); 7801 return 0; 7802} 7803 7804static void cpu_cgroup_css_free(struct cgroup_subsys_state *css) 7805{ 7806 struct task_group *tg = css_tg(css); 7807 7808 sched_destroy_group(tg); 7809} 7810 7811static void cpu_cgroup_css_offline(struct cgroup_subsys_state *css) 7812{ 7813 struct task_group *tg = css_tg(css); 7814 7815 sched_offline_group(tg); 7816} 7817 7818static int cpu_cgroup_can_attach(struct cgroup_subsys_state *css, 7819 struct cgroup_taskset *tset) 7820{ 7821 struct task_struct *task; 7822 7823 cgroup_taskset_for_each(task, tset) { 7824#ifdef CONFIG_RT_GROUP_SCHED 7825 if (!sched_rt_can_attach(css_tg(css), task)) 7826 return -EINVAL; 7827#else 7828 /* We don't support RT-tasks being in separate groups */ 7829 if (task->sched_class != &fair_sched_class) 7830 return -EINVAL; 7831#endif 7832 } 7833 return 0; 7834} 7835 7836static void cpu_cgroup_attach(struct cgroup_subsys_state *css, 7837 struct cgroup_taskset *tset) 7838{ 7839 struct task_struct *task; 7840 7841 cgroup_taskset_for_each(task, tset) 7842 sched_move_task(task); 7843} 7844 7845static void cpu_cgroup_exit(struct cgroup_subsys_state *css, 7846 struct cgroup_subsys_state *old_css, 7847 struct task_struct *task) 7848{ 7849 /* 7850 * cgroup_exit() is called in the copy_process() failure path. 7851 * Ignore this case since the task hasn't ran yet, this avoids 7852 * trying to poke a half freed task state from generic code. 7853 */ 7854 if (!(task->flags & PF_EXITING)) 7855 return; 7856 7857 sched_move_task(task); 7858} 7859 7860#ifdef CONFIG_FAIR_GROUP_SCHED 7861static int cpu_shares_write_u64(struct cgroup_subsys_state *css, 7862 struct cftype *cftype, u64 shareval) 7863{ 7864 return sched_group_set_shares(css_tg(css), scale_load(shareval)); 7865} 7866 7867static u64 cpu_shares_read_u64(struct cgroup_subsys_state *css, 7868 struct cftype *cft) 7869{ 7870 struct task_group *tg = css_tg(css); 7871 7872 return (u64) scale_load_down(tg->shares); 7873} 7874 7875#ifdef CONFIG_CFS_BANDWIDTH 7876static DEFINE_MUTEX(cfs_constraints_mutex); 7877 7878const u64 max_cfs_quota_period = 1 * NSEC_PER_SEC; /* 1s */ 7879const u64 min_cfs_quota_period = 1 * NSEC_PER_MSEC; /* 1ms */ 7880 7881static int __cfs_schedulable(struct task_group *tg, u64 period, u64 runtime); 7882 7883static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota) 7884{ 7885 int i, ret = 0, runtime_enabled, runtime_was_enabled; 7886 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 7887 7888 if (tg == &root_task_group) 7889 return -EINVAL; 7890 7891 /* 7892 * Ensure we have at some amount of bandwidth every period. This is 7893 * to prevent reaching a state of large arrears when throttled via 7894 * entity_tick() resulting in prolonged exit starvation. 7895 */ 7896 if (quota < min_cfs_quota_period || period < min_cfs_quota_period) 7897 return -EINVAL; 7898 7899 /* 7900 * Likewise, bound things on the otherside by preventing insane quota 7901 * periods. This also allows us to normalize in computing quota 7902 * feasibility. 7903 */ 7904 if (period > max_cfs_quota_period) 7905 return -EINVAL; 7906 7907 /* 7908 * Prevent race between setting of cfs_rq->runtime_enabled and 7909 * unthrottle_offline_cfs_rqs(). 7910 */ 7911 get_online_cpus(); 7912 mutex_lock(&cfs_constraints_mutex); 7913 ret = __cfs_schedulable(tg, period, quota); 7914 if (ret) 7915 goto out_unlock; 7916 7917 runtime_enabled = quota != RUNTIME_INF; 7918 runtime_was_enabled = cfs_b->quota != RUNTIME_INF; 7919 /* 7920 * If we need to toggle cfs_bandwidth_used, off->on must occur 7921 * before making related changes, and on->off must occur afterwards 7922 */ 7923 if (runtime_enabled && !runtime_was_enabled) 7924 cfs_bandwidth_usage_inc(); 7925 raw_spin_lock_irq(&cfs_b->lock); 7926 cfs_b->period = ns_to_ktime(period); 7927 cfs_b->quota = quota; 7928 7929 __refill_cfs_bandwidth_runtime(cfs_b); 7930 /* restart the period timer (if active) to handle new period expiry */ 7931 if (runtime_enabled && cfs_b->timer_active) { 7932 /* force a reprogram */ 7933 __start_cfs_bandwidth(cfs_b, true); 7934 } 7935 raw_spin_unlock_irq(&cfs_b->lock); 7936 7937 for_each_online_cpu(i) { 7938 struct cfs_rq *cfs_rq = tg->cfs_rq[i]; 7939 struct rq *rq = cfs_rq->rq; 7940 7941 raw_spin_lock_irq(&rq->lock); 7942 cfs_rq->runtime_enabled = runtime_enabled; 7943 cfs_rq->runtime_remaining = 0; 7944 7945 if (cfs_rq->throttled) 7946 unthrottle_cfs_rq(cfs_rq); 7947 raw_spin_unlock_irq(&rq->lock); 7948 } 7949 if (runtime_was_enabled && !runtime_enabled) 7950 cfs_bandwidth_usage_dec(); 7951out_unlock: 7952 mutex_unlock(&cfs_constraints_mutex); 7953 put_online_cpus(); 7954 7955 return ret; 7956} 7957 7958int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us) 7959{ 7960 u64 quota, period; 7961 7962 period = ktime_to_ns(tg->cfs_bandwidth.period); 7963 if (cfs_quota_us < 0) 7964 quota = RUNTIME_INF; 7965 else 7966 quota = (u64)cfs_quota_us * NSEC_PER_USEC; 7967 7968 return tg_set_cfs_bandwidth(tg, period, quota); 7969} 7970 7971long tg_get_cfs_quota(struct task_group *tg) 7972{ 7973 u64 quota_us; 7974 7975 if (tg->cfs_bandwidth.quota == RUNTIME_INF) 7976 return -1; 7977 7978 quota_us = tg->cfs_bandwidth.quota; 7979 do_div(quota_us, NSEC_PER_USEC); 7980 7981 return quota_us; 7982} 7983 7984int tg_set_cfs_period(struct task_group *tg, long cfs_period_us) 7985{ 7986 u64 quota, period; 7987 7988 period = (u64)cfs_period_us * NSEC_PER_USEC; 7989 quota = tg->cfs_bandwidth.quota; 7990 7991 return tg_set_cfs_bandwidth(tg, period, quota); 7992} 7993 7994long tg_get_cfs_period(struct task_group *tg) 7995{ 7996 u64 cfs_period_us; 7997 7998 cfs_period_us = ktime_to_ns(tg->cfs_bandwidth.period); 7999 do_div(cfs_period_us, NSEC_PER_USEC); 8000 8001 return cfs_period_us; 8002} 8003 8004static s64 cpu_cfs_quota_read_s64(struct cgroup_subsys_state *css, 8005 struct cftype *cft) 8006{ 8007 return tg_get_cfs_quota(css_tg(css)); 8008} 8009 8010static int cpu_cfs_quota_write_s64(struct cgroup_subsys_state *css, 8011 struct cftype *cftype, s64 cfs_quota_us) 8012{ 8013 return tg_set_cfs_quota(css_tg(css), cfs_quota_us); 8014} 8015 8016static u64 cpu_cfs_period_read_u64(struct cgroup_subsys_state *css, 8017 struct cftype *cft) 8018{ 8019 return tg_get_cfs_period(css_tg(css)); 8020} 8021 8022static int cpu_cfs_period_write_u64(struct cgroup_subsys_state *css, 8023 struct cftype *cftype, u64 cfs_period_us) 8024{ 8025 return tg_set_cfs_period(css_tg(css), cfs_period_us); 8026} 8027 8028struct cfs_schedulable_data { 8029 struct task_group *tg; 8030 u64 period, quota; 8031}; 8032 8033/* 8034 * normalize group quota/period to be quota/max_period 8035 * note: units are usecs 8036 */ 8037static u64 normalize_cfs_quota(struct task_group *tg, 8038 struct cfs_schedulable_data *d) 8039{ 8040 u64 quota, period; 8041 8042 if (tg == d->tg) { 8043 period = d->period; 8044 quota = d->quota; 8045 } else { 8046 period = tg_get_cfs_period(tg); 8047 quota = tg_get_cfs_quota(tg); 8048 } 8049 8050 /* note: these should typically be equivalent */ 8051 if (quota == RUNTIME_INF || quota == -1) 8052 return RUNTIME_INF; 8053 8054 return to_ratio(period, quota); 8055} 8056 8057static int tg_cfs_schedulable_down(struct task_group *tg, void *data) 8058{ 8059 struct cfs_schedulable_data *d = data; 8060 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 8061 s64 quota = 0, parent_quota = -1; 8062 8063 if (!tg->parent) { 8064 quota = RUNTIME_INF; 8065 } else { 8066 struct cfs_bandwidth *parent_b = &tg->parent->cfs_bandwidth; 8067 8068 quota = normalize_cfs_quota(tg, d); 8069 parent_quota = parent_b->hierarchal_quota; 8070 8071 /* 8072 * ensure max(child_quota) <= parent_quota, inherit when no 8073 * limit is set 8074 */ 8075 if (quota == RUNTIME_INF) 8076 quota = parent_quota; 8077 else if (parent_quota != RUNTIME_INF && quota > parent_quota) 8078 return -EINVAL; 8079 } 8080 cfs_b->hierarchal_quota = quota; 8081 8082 return 0; 8083} 8084 8085static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota) 8086{ 8087 int ret; 8088 struct cfs_schedulable_data data = { 8089 .tg = tg, 8090 .period = period, 8091 .quota = quota, 8092 }; 8093 8094 if (quota != RUNTIME_INF) { 8095 do_div(data.period, NSEC_PER_USEC); 8096 do_div(data.quota, NSEC_PER_USEC); 8097 } 8098 8099 rcu_read_lock(); 8100 ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data); 8101 rcu_read_unlock(); 8102 8103 return ret; 8104} 8105 8106static int cpu_stats_show(struct seq_file *sf, void *v) 8107{ 8108 struct task_group *tg = css_tg(seq_css(sf)); 8109 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 8110 8111 seq_printf(sf, "nr_periods %d\n", cfs_b->nr_periods); 8112 seq_printf(sf, "nr_throttled %d\n", cfs_b->nr_throttled); 8113 seq_printf(sf, "throttled_time %llu\n", cfs_b->throttled_time); 8114 8115 return 0; 8116} 8117#endif /* CONFIG_CFS_BANDWIDTH */ 8118#endif /* CONFIG_FAIR_GROUP_SCHED */ 8119 8120#ifdef CONFIG_RT_GROUP_SCHED 8121static int cpu_rt_runtime_write(struct cgroup_subsys_state *css, 8122 struct cftype *cft, s64 val) 8123{ 8124 return sched_group_set_rt_runtime(css_tg(css), val); 8125} 8126 8127static s64 cpu_rt_runtime_read(struct cgroup_subsys_state *css, 8128 struct cftype *cft) 8129{ 8130 return sched_group_rt_runtime(css_tg(css)); 8131} 8132 8133static int cpu_rt_period_write_uint(struct cgroup_subsys_state *css, 8134 struct cftype *cftype, u64 rt_period_us) 8135{ 8136 return sched_group_set_rt_period(css_tg(css), rt_period_us); 8137} 8138 8139static u64 cpu_rt_period_read_uint(struct cgroup_subsys_state *css, 8140 struct cftype *cft) 8141{ 8142 return sched_group_rt_period(css_tg(css)); 8143} 8144#endif /* CONFIG_RT_GROUP_SCHED */ 8145 8146static struct cftype cpu_files[] = { 8147#ifdef CONFIG_FAIR_GROUP_SCHED 8148 { 8149 .name = "shares", 8150 .read_u64 = cpu_shares_read_u64, 8151 .write_u64 = cpu_shares_write_u64, 8152 }, 8153#endif 8154#ifdef CONFIG_CFS_BANDWIDTH 8155 { 8156 .name = "cfs_quota_us", 8157 .read_s64 = cpu_cfs_quota_read_s64, 8158 .write_s64 = cpu_cfs_quota_write_s64, 8159 }, 8160 { 8161 .name = "cfs_period_us", 8162 .read_u64 = cpu_cfs_period_read_u64, 8163 .write_u64 = cpu_cfs_period_write_u64, 8164 }, 8165 { 8166 .name = "stat", 8167 .seq_show = cpu_stats_show, 8168 }, 8169#endif 8170#ifdef CONFIG_RT_GROUP_SCHED 8171 { 8172 .name = "rt_runtime_us", 8173 .read_s64 = cpu_rt_runtime_read, 8174 .write_s64 = cpu_rt_runtime_write, 8175 }, 8176 { 8177 .name = "rt_period_us", 8178 .read_u64 = cpu_rt_period_read_uint, 8179 .write_u64 = cpu_rt_period_write_uint, 8180 }, 8181#endif 8182 { } /* terminate */ 8183}; 8184 8185struct cgroup_subsys cpu_cgrp_subsys = { 8186 .css_alloc = cpu_cgroup_css_alloc, 8187 .css_free = cpu_cgroup_css_free, 8188 .css_online = cpu_cgroup_css_online, 8189 .css_offline = cpu_cgroup_css_offline, 8190 .can_attach = cpu_cgroup_can_attach, 8191 .attach = cpu_cgroup_attach, 8192 .exit = cpu_cgroup_exit, 8193 .legacy_cftypes = cpu_files, 8194 .early_init = 1, 8195}; 8196 8197#endif /* CONFIG_CGROUP_SCHED */ 8198 8199void dump_cpu_task(int cpu) 8200{ 8201 pr_info("Task dump for CPU %d:\n", cpu); 8202 sched_show_task(cpu_curr(cpu)); 8203} 8204