core.c revision 143cf23df25b7082cd706c3c53188e741e7881c3
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 93void start_bandwidth_timer(struct hrtimer *period_timer, ktime_t period) 94{ 95 unsigned long delta; 96 ktime_t soft, hard, now; 97 98 for (;;) { 99 if (hrtimer_active(period_timer)) 100 break; 101 102 now = hrtimer_cb_get_time(period_timer); 103 hrtimer_forward(period_timer, now, period); 104 105 soft = hrtimer_get_softexpires(period_timer); 106 hard = hrtimer_get_expires(period_timer); 107 delta = ktime_to_ns(ktime_sub(hard, soft)); 108 __hrtimer_start_range_ns(period_timer, soft, delta, 109 HRTIMER_MODE_ABS_PINNED, 0); 110 } 111} 112 113DEFINE_MUTEX(sched_domains_mutex); 114DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); 115 116static void update_rq_clock_task(struct rq *rq, s64 delta); 117 118void update_rq_clock(struct rq *rq) 119{ 120 s64 delta; 121 122 if (rq->skip_clock_update > 0) 123 return; 124 125 delta = sched_clock_cpu(cpu_of(rq)) - rq->clock; 126 rq->clock += delta; 127 update_rq_clock_task(rq, delta); 128} 129 130/* 131 * Debugging: various feature bits 132 */ 133 134#define SCHED_FEAT(name, enabled) \ 135 (1UL << __SCHED_FEAT_##name) * enabled | 136 137const_debug unsigned int sysctl_sched_features = 138#include "features.h" 139 0; 140 141#undef SCHED_FEAT 142 143#ifdef CONFIG_SCHED_DEBUG 144#define SCHED_FEAT(name, enabled) \ 145 #name , 146 147static const char * const sched_feat_names[] = { 148#include "features.h" 149}; 150 151#undef SCHED_FEAT 152 153static int sched_feat_show(struct seq_file *m, void *v) 154{ 155 int i; 156 157 for (i = 0; i < __SCHED_FEAT_NR; i++) { 158 if (!(sysctl_sched_features & (1UL << i))) 159 seq_puts(m, "NO_"); 160 seq_printf(m, "%s ", sched_feat_names[i]); 161 } 162 seq_puts(m, "\n"); 163 164 return 0; 165} 166 167#ifdef HAVE_JUMP_LABEL 168 169#define jump_label_key__true STATIC_KEY_INIT_TRUE 170#define jump_label_key__false STATIC_KEY_INIT_FALSE 171 172#define SCHED_FEAT(name, enabled) \ 173 jump_label_key__##enabled , 174 175struct static_key sched_feat_keys[__SCHED_FEAT_NR] = { 176#include "features.h" 177}; 178 179#undef SCHED_FEAT 180 181static void sched_feat_disable(int i) 182{ 183 if (static_key_enabled(&sched_feat_keys[i])) 184 static_key_slow_dec(&sched_feat_keys[i]); 185} 186 187static void sched_feat_enable(int i) 188{ 189 if (!static_key_enabled(&sched_feat_keys[i])) 190 static_key_slow_inc(&sched_feat_keys[i]); 191} 192#else 193static void sched_feat_disable(int i) { }; 194static void sched_feat_enable(int i) { }; 195#endif /* HAVE_JUMP_LABEL */ 196 197static int sched_feat_set(char *cmp) 198{ 199 int i; 200 int neg = 0; 201 202 if (strncmp(cmp, "NO_", 3) == 0) { 203 neg = 1; 204 cmp += 3; 205 } 206 207 for (i = 0; i < __SCHED_FEAT_NR; i++) { 208 if (strcmp(cmp, sched_feat_names[i]) == 0) { 209 if (neg) { 210 sysctl_sched_features &= ~(1UL << i); 211 sched_feat_disable(i); 212 } else { 213 sysctl_sched_features |= (1UL << i); 214 sched_feat_enable(i); 215 } 216 break; 217 } 218 } 219 220 return i; 221} 222 223static ssize_t 224sched_feat_write(struct file *filp, const char __user *ubuf, 225 size_t cnt, loff_t *ppos) 226{ 227 char buf[64]; 228 char *cmp; 229 int i; 230 231 if (cnt > 63) 232 cnt = 63; 233 234 if (copy_from_user(&buf, ubuf, cnt)) 235 return -EFAULT; 236 237 buf[cnt] = 0; 238 cmp = strstrip(buf); 239 240 i = sched_feat_set(cmp); 241 if (i == __SCHED_FEAT_NR) 242 return -EINVAL; 243 244 *ppos += cnt; 245 246 return cnt; 247} 248 249static int sched_feat_open(struct inode *inode, struct file *filp) 250{ 251 return single_open(filp, sched_feat_show, NULL); 252} 253 254static const struct file_operations sched_feat_fops = { 255 .open = sched_feat_open, 256 .write = sched_feat_write, 257 .read = seq_read, 258 .llseek = seq_lseek, 259 .release = single_release, 260}; 261 262static __init int sched_init_debug(void) 263{ 264 debugfs_create_file("sched_features", 0644, NULL, NULL, 265 &sched_feat_fops); 266 267 return 0; 268} 269late_initcall(sched_init_debug); 270#endif /* CONFIG_SCHED_DEBUG */ 271 272/* 273 * Number of tasks to iterate in a single balance run. 274 * Limited because this is done with IRQs disabled. 275 */ 276const_debug unsigned int sysctl_sched_nr_migrate = 32; 277 278/* 279 * period over which we average the RT time consumption, measured 280 * in ms. 281 * 282 * default: 1s 283 */ 284const_debug unsigned int sysctl_sched_time_avg = MSEC_PER_SEC; 285 286/* 287 * period over which we measure -rt task cpu usage in us. 288 * default: 1s 289 */ 290unsigned int sysctl_sched_rt_period = 1000000; 291 292__read_mostly int scheduler_running; 293 294/* 295 * part of the period that we allow rt tasks to run in us. 296 * default: 0.95s 297 */ 298int sysctl_sched_rt_runtime = 950000; 299 300/* 301 * __task_rq_lock - lock the rq @p resides on. 302 */ 303static inline struct rq *__task_rq_lock(struct task_struct *p) 304 __acquires(rq->lock) 305{ 306 struct rq *rq; 307 308 lockdep_assert_held(&p->pi_lock); 309 310 for (;;) { 311 rq = task_rq(p); 312 raw_spin_lock(&rq->lock); 313 if (likely(rq == task_rq(p))) 314 return rq; 315 raw_spin_unlock(&rq->lock); 316 } 317} 318 319/* 320 * task_rq_lock - lock p->pi_lock and lock the rq @p resides on. 321 */ 322static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags) 323 __acquires(p->pi_lock) 324 __acquires(rq->lock) 325{ 326 struct rq *rq; 327 328 for (;;) { 329 raw_spin_lock_irqsave(&p->pi_lock, *flags); 330 rq = task_rq(p); 331 raw_spin_lock(&rq->lock); 332 if (likely(rq == task_rq(p))) 333 return rq; 334 raw_spin_unlock(&rq->lock); 335 raw_spin_unlock_irqrestore(&p->pi_lock, *flags); 336 } 337} 338 339static void __task_rq_unlock(struct rq *rq) 340 __releases(rq->lock) 341{ 342 raw_spin_unlock(&rq->lock); 343} 344 345static inline void 346task_rq_unlock(struct rq *rq, struct task_struct *p, unsigned long *flags) 347 __releases(rq->lock) 348 __releases(p->pi_lock) 349{ 350 raw_spin_unlock(&rq->lock); 351 raw_spin_unlock_irqrestore(&p->pi_lock, *flags); 352} 353 354/* 355 * this_rq_lock - lock this runqueue and disable interrupts. 356 */ 357static struct rq *this_rq_lock(void) 358 __acquires(rq->lock) 359{ 360 struct rq *rq; 361 362 local_irq_disable(); 363 rq = this_rq(); 364 raw_spin_lock(&rq->lock); 365 366 return rq; 367} 368 369#ifdef CONFIG_SCHED_HRTICK 370/* 371 * Use HR-timers to deliver accurate preemption points. 372 */ 373 374static void hrtick_clear(struct rq *rq) 375{ 376 if (hrtimer_active(&rq->hrtick_timer)) 377 hrtimer_cancel(&rq->hrtick_timer); 378} 379 380/* 381 * High-resolution timer tick. 382 * Runs from hardirq context with interrupts disabled. 383 */ 384static enum hrtimer_restart hrtick(struct hrtimer *timer) 385{ 386 struct rq *rq = container_of(timer, struct rq, hrtick_timer); 387 388 WARN_ON_ONCE(cpu_of(rq) != smp_processor_id()); 389 390 raw_spin_lock(&rq->lock); 391 update_rq_clock(rq); 392 rq->curr->sched_class->task_tick(rq, rq->curr, 1); 393 raw_spin_unlock(&rq->lock); 394 395 return HRTIMER_NORESTART; 396} 397 398#ifdef CONFIG_SMP 399 400static int __hrtick_restart(struct rq *rq) 401{ 402 struct hrtimer *timer = &rq->hrtick_timer; 403 ktime_t time = hrtimer_get_softexpires(timer); 404 405 return __hrtimer_start_range_ns(timer, time, 0, HRTIMER_MODE_ABS_PINNED, 0); 406} 407 408/* 409 * called from hardirq (IPI) context 410 */ 411static void __hrtick_start(void *arg) 412{ 413 struct rq *rq = arg; 414 415 raw_spin_lock(&rq->lock); 416 __hrtick_restart(rq); 417 rq->hrtick_csd_pending = 0; 418 raw_spin_unlock(&rq->lock); 419} 420 421/* 422 * Called to set the hrtick timer state. 423 * 424 * called with rq->lock held and irqs disabled 425 */ 426void hrtick_start(struct rq *rq, u64 delay) 427{ 428 struct hrtimer *timer = &rq->hrtick_timer; 429 ktime_t time = ktime_add_ns(timer->base->get_time(), delay); 430 431 hrtimer_set_expires(timer, time); 432 433 if (rq == this_rq()) { 434 __hrtick_restart(rq); 435 } else if (!rq->hrtick_csd_pending) { 436 smp_call_function_single_async(cpu_of(rq), &rq->hrtick_csd); 437 rq->hrtick_csd_pending = 1; 438 } 439} 440 441static int 442hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu) 443{ 444 int cpu = (int)(long)hcpu; 445 446 switch (action) { 447 case CPU_UP_CANCELED: 448 case CPU_UP_CANCELED_FROZEN: 449 case CPU_DOWN_PREPARE: 450 case CPU_DOWN_PREPARE_FROZEN: 451 case CPU_DEAD: 452 case CPU_DEAD_FROZEN: 453 hrtick_clear(cpu_rq(cpu)); 454 return NOTIFY_OK; 455 } 456 457 return NOTIFY_DONE; 458} 459 460static __init void init_hrtick(void) 461{ 462 hotcpu_notifier(hotplug_hrtick, 0); 463} 464#else 465/* 466 * Called to set the hrtick timer state. 467 * 468 * called with rq->lock held and irqs disabled 469 */ 470void hrtick_start(struct rq *rq, u64 delay) 471{ 472 __hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0, 473 HRTIMER_MODE_REL_PINNED, 0); 474} 475 476static inline void init_hrtick(void) 477{ 478} 479#endif /* CONFIG_SMP */ 480 481static void init_rq_hrtick(struct rq *rq) 482{ 483#ifdef CONFIG_SMP 484 rq->hrtick_csd_pending = 0; 485 486 rq->hrtick_csd.flags = 0; 487 rq->hrtick_csd.func = __hrtick_start; 488 rq->hrtick_csd.info = rq; 489#endif 490 491 hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 492 rq->hrtick_timer.function = hrtick; 493} 494#else /* CONFIG_SCHED_HRTICK */ 495static inline void hrtick_clear(struct rq *rq) 496{ 497} 498 499static inline void init_rq_hrtick(struct rq *rq) 500{ 501} 502 503static inline void init_hrtick(void) 504{ 505} 506#endif /* CONFIG_SCHED_HRTICK */ 507 508/* 509 * resched_task - mark a task 'to be rescheduled now'. 510 * 511 * On UP this means the setting of the need_resched flag, on SMP it 512 * might also involve a cross-CPU call to trigger the scheduler on 513 * the target CPU. 514 */ 515void resched_task(struct task_struct *p) 516{ 517 int cpu; 518 519 lockdep_assert_held(&task_rq(p)->lock); 520 521 if (test_tsk_need_resched(p)) 522 return; 523 524 set_tsk_need_resched(p); 525 526 cpu = task_cpu(p); 527 if (cpu == smp_processor_id()) { 528 set_preempt_need_resched(); 529 return; 530 } 531 532 /* NEED_RESCHED must be visible before we test polling */ 533 smp_mb(); 534 if (!tsk_is_polling(p)) 535 smp_send_reschedule(cpu); 536} 537 538void resched_cpu(int cpu) 539{ 540 struct rq *rq = cpu_rq(cpu); 541 unsigned long flags; 542 543 if (!raw_spin_trylock_irqsave(&rq->lock, flags)) 544 return; 545 resched_task(cpu_curr(cpu)); 546 raw_spin_unlock_irqrestore(&rq->lock, flags); 547} 548 549#ifdef CONFIG_SMP 550#ifdef CONFIG_NO_HZ_COMMON 551/* 552 * In the semi idle case, use the nearest busy cpu for migrating timers 553 * from an idle cpu. This is good for power-savings. 554 * 555 * We don't do similar optimization for completely idle system, as 556 * selecting an idle cpu will add more delays to the timers than intended 557 * (as that cpu's timer base may not be uptodate wrt jiffies etc). 558 */ 559int get_nohz_timer_target(int pinned) 560{ 561 int cpu = smp_processor_id(); 562 int i; 563 struct sched_domain *sd; 564 565 if (pinned || !get_sysctl_timer_migration() || !idle_cpu(cpu)) 566 return cpu; 567 568 rcu_read_lock(); 569 for_each_domain(cpu, sd) { 570 for_each_cpu(i, sched_domain_span(sd)) { 571 if (!idle_cpu(i)) { 572 cpu = i; 573 goto unlock; 574 } 575 } 576 } 577unlock: 578 rcu_read_unlock(); 579 return cpu; 580} 581/* 582 * When add_timer_on() enqueues a timer into the timer wheel of an 583 * idle CPU then this timer might expire before the next timer event 584 * which is scheduled to wake up that CPU. In case of a completely 585 * idle system the next event might even be infinite time into the 586 * future. wake_up_idle_cpu() ensures that the CPU is woken up and 587 * leaves the inner idle loop so the newly added timer is taken into 588 * account when the CPU goes back to idle and evaluates the timer 589 * wheel for the next timer event. 590 */ 591static void wake_up_idle_cpu(int cpu) 592{ 593 struct rq *rq = cpu_rq(cpu); 594 595 if (cpu == smp_processor_id()) 596 return; 597 598 /* 599 * This is safe, as this function is called with the timer 600 * wheel base lock of (cpu) held. When the CPU is on the way 601 * to idle and has not yet set rq->curr to idle then it will 602 * be serialized on the timer wheel base lock and take the new 603 * timer into account automatically. 604 */ 605 if (rq->curr != rq->idle) 606 return; 607 608 /* 609 * We can set TIF_RESCHED on the idle task of the other CPU 610 * lockless. The worst case is that the other CPU runs the 611 * idle task through an additional NOOP schedule() 612 */ 613 set_tsk_need_resched(rq->idle); 614 615 /* NEED_RESCHED must be visible before we test polling */ 616 smp_mb(); 617 if (!tsk_is_polling(rq->idle)) 618 smp_send_reschedule(cpu); 619} 620 621static bool wake_up_full_nohz_cpu(int cpu) 622{ 623 if (tick_nohz_full_cpu(cpu)) { 624 if (cpu != smp_processor_id() || 625 tick_nohz_tick_stopped()) 626 smp_send_reschedule(cpu); 627 return true; 628 } 629 630 return false; 631} 632 633void wake_up_nohz_cpu(int cpu) 634{ 635 if (!wake_up_full_nohz_cpu(cpu)) 636 wake_up_idle_cpu(cpu); 637} 638 639static inline bool got_nohz_idle_kick(void) 640{ 641 int cpu = smp_processor_id(); 642 643 if (!test_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu))) 644 return false; 645 646 if (idle_cpu(cpu) && !need_resched()) 647 return true; 648 649 /* 650 * We can't run Idle Load Balance on this CPU for this time so we 651 * cancel it and clear NOHZ_BALANCE_KICK 652 */ 653 clear_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu)); 654 return false; 655} 656 657#else /* CONFIG_NO_HZ_COMMON */ 658 659static inline bool got_nohz_idle_kick(void) 660{ 661 return false; 662} 663 664#endif /* CONFIG_NO_HZ_COMMON */ 665 666#ifdef CONFIG_NO_HZ_FULL 667bool sched_can_stop_tick(void) 668{ 669 struct rq *rq; 670 671 rq = this_rq(); 672 673 /* Make sure rq->nr_running update is visible after the IPI */ 674 smp_rmb(); 675 676 /* More than one running task need preemption */ 677 if (rq->nr_running > 1) 678 return false; 679 680 return true; 681} 682#endif /* CONFIG_NO_HZ_FULL */ 683 684void sched_avg_update(struct rq *rq) 685{ 686 s64 period = sched_avg_period(); 687 688 while ((s64)(rq_clock(rq) - rq->age_stamp) > period) { 689 /* 690 * Inline assembly required to prevent the compiler 691 * optimising this loop into a divmod call. 692 * See __iter_div_u64_rem() for another example of this. 693 */ 694 asm("" : "+rm" (rq->age_stamp)); 695 rq->age_stamp += period; 696 rq->rt_avg /= 2; 697 } 698} 699 700#endif /* CONFIG_SMP */ 701 702#if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \ 703 (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH))) 704/* 705 * Iterate task_group tree rooted at *from, calling @down when first entering a 706 * node and @up when leaving it for the final time. 707 * 708 * Caller must hold rcu_lock or sufficient equivalent. 709 */ 710int walk_tg_tree_from(struct task_group *from, 711 tg_visitor down, tg_visitor up, void *data) 712{ 713 struct task_group *parent, *child; 714 int ret; 715 716 parent = from; 717 718down: 719 ret = (*down)(parent, data); 720 if (ret) 721 goto out; 722 list_for_each_entry_rcu(child, &parent->children, siblings) { 723 parent = child; 724 goto down; 725 726up: 727 continue; 728 } 729 ret = (*up)(parent, data); 730 if (ret || parent == from) 731 goto out; 732 733 child = parent; 734 parent = parent->parent; 735 if (parent) 736 goto up; 737out: 738 return ret; 739} 740 741int tg_nop(struct task_group *tg, void *data) 742{ 743 return 0; 744} 745#endif 746 747static void set_load_weight(struct task_struct *p) 748{ 749 int prio = p->static_prio - MAX_RT_PRIO; 750 struct load_weight *load = &p->se.load; 751 752 /* 753 * SCHED_IDLE tasks get minimal weight: 754 */ 755 if (p->policy == SCHED_IDLE) { 756 load->weight = scale_load(WEIGHT_IDLEPRIO); 757 load->inv_weight = WMULT_IDLEPRIO; 758 return; 759 } 760 761 load->weight = scale_load(prio_to_weight[prio]); 762 load->inv_weight = prio_to_wmult[prio]; 763} 764 765static void enqueue_task(struct rq *rq, struct task_struct *p, int flags) 766{ 767 update_rq_clock(rq); 768 sched_info_queued(rq, p); 769 p->sched_class->enqueue_task(rq, p, flags); 770} 771 772static void dequeue_task(struct rq *rq, struct task_struct *p, int flags) 773{ 774 update_rq_clock(rq); 775 sched_info_dequeued(rq, p); 776 p->sched_class->dequeue_task(rq, p, flags); 777} 778 779void activate_task(struct rq *rq, struct task_struct *p, int flags) 780{ 781 if (task_contributes_to_load(p)) 782 rq->nr_uninterruptible--; 783 784 enqueue_task(rq, p, flags); 785} 786 787void deactivate_task(struct rq *rq, struct task_struct *p, int flags) 788{ 789 if (task_contributes_to_load(p)) 790 rq->nr_uninterruptible++; 791 792 dequeue_task(rq, p, flags); 793} 794 795static void update_rq_clock_task(struct rq *rq, s64 delta) 796{ 797/* 798 * In theory, the compile should just see 0 here, and optimize out the call 799 * to sched_rt_avg_update. But I don't trust it... 800 */ 801#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) 802 s64 steal = 0, irq_delta = 0; 803#endif 804#ifdef CONFIG_IRQ_TIME_ACCOUNTING 805 irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time; 806 807 /* 808 * Since irq_time is only updated on {soft,}irq_exit, we might run into 809 * this case when a previous update_rq_clock() happened inside a 810 * {soft,}irq region. 811 * 812 * When this happens, we stop ->clock_task and only update the 813 * prev_irq_time stamp to account for the part that fit, so that a next 814 * update will consume the rest. This ensures ->clock_task is 815 * monotonic. 816 * 817 * It does however cause some slight miss-attribution of {soft,}irq 818 * time, a more accurate solution would be to update the irq_time using 819 * the current rq->clock timestamp, except that would require using 820 * atomic ops. 821 */ 822 if (irq_delta > delta) 823 irq_delta = delta; 824 825 rq->prev_irq_time += irq_delta; 826 delta -= irq_delta; 827#endif 828#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING 829 if (static_key_false((¶virt_steal_rq_enabled))) { 830 steal = paravirt_steal_clock(cpu_of(rq)); 831 steal -= rq->prev_steal_time_rq; 832 833 if (unlikely(steal > delta)) 834 steal = delta; 835 836 rq->prev_steal_time_rq += steal; 837 delta -= steal; 838 } 839#endif 840 841 rq->clock_task += delta; 842 843#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) 844 if ((irq_delta + steal) && sched_feat(NONTASK_POWER)) 845 sched_rt_avg_update(rq, irq_delta + steal); 846#endif 847} 848 849void sched_set_stop_task(int cpu, struct task_struct *stop) 850{ 851 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 }; 852 struct task_struct *old_stop = cpu_rq(cpu)->stop; 853 854 if (stop) { 855 /* 856 * Make it appear like a SCHED_FIFO task, its something 857 * userspace knows about and won't get confused about. 858 * 859 * Also, it will make PI more or less work without too 860 * much confusion -- but then, stop work should not 861 * rely on PI working anyway. 862 */ 863 sched_setscheduler_nocheck(stop, SCHED_FIFO, ¶m); 864 865 stop->sched_class = &stop_sched_class; 866 } 867 868 cpu_rq(cpu)->stop = stop; 869 870 if (old_stop) { 871 /* 872 * Reset it back to a normal scheduling class so that 873 * it can die in pieces. 874 */ 875 old_stop->sched_class = &rt_sched_class; 876 } 877} 878 879/* 880 * __normal_prio - return the priority that is based on the static prio 881 */ 882static inline int __normal_prio(struct task_struct *p) 883{ 884 return p->static_prio; 885} 886 887/* 888 * Calculate the expected normal priority: i.e. priority 889 * without taking RT-inheritance into account. Might be 890 * boosted by interactivity modifiers. Changes upon fork, 891 * setprio syscalls, and whenever the interactivity 892 * estimator recalculates. 893 */ 894static inline int normal_prio(struct task_struct *p) 895{ 896 int prio; 897 898 if (task_has_dl_policy(p)) 899 prio = MAX_DL_PRIO-1; 900 else if (task_has_rt_policy(p)) 901 prio = MAX_RT_PRIO-1 - p->rt_priority; 902 else 903 prio = __normal_prio(p); 904 return prio; 905} 906 907/* 908 * Calculate the current priority, i.e. the priority 909 * taken into account by the scheduler. This value might 910 * be boosted by RT tasks, or might be boosted by 911 * interactivity modifiers. Will be RT if the task got 912 * RT-boosted. If not then it returns p->normal_prio. 913 */ 914static int effective_prio(struct task_struct *p) 915{ 916 p->normal_prio = normal_prio(p); 917 /* 918 * If we are RT tasks or we were boosted to RT priority, 919 * keep the priority unchanged. Otherwise, update priority 920 * to the normal priority: 921 */ 922 if (!rt_prio(p->prio)) 923 return p->normal_prio; 924 return p->prio; 925} 926 927/** 928 * task_curr - is this task currently executing on a CPU? 929 * @p: the task in question. 930 * 931 * Return: 1 if the task is currently executing. 0 otherwise. 932 */ 933inline int task_curr(const struct task_struct *p) 934{ 935 return cpu_curr(task_cpu(p)) == p; 936} 937 938static inline void check_class_changed(struct rq *rq, struct task_struct *p, 939 const struct sched_class *prev_class, 940 int oldprio) 941{ 942 if (prev_class != p->sched_class) { 943 if (prev_class->switched_from) 944 prev_class->switched_from(rq, p); 945 p->sched_class->switched_to(rq, p); 946 } else if (oldprio != p->prio || dl_task(p)) 947 p->sched_class->prio_changed(rq, p, oldprio); 948} 949 950void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags) 951{ 952 const struct sched_class *class; 953 954 if (p->sched_class == rq->curr->sched_class) { 955 rq->curr->sched_class->check_preempt_curr(rq, p, flags); 956 } else { 957 for_each_class(class) { 958 if (class == rq->curr->sched_class) 959 break; 960 if (class == p->sched_class) { 961 resched_task(rq->curr); 962 break; 963 } 964 } 965 } 966 967 /* 968 * A queue event has occurred, and we're going to schedule. In 969 * this case, we can save a useless back to back clock update. 970 */ 971 if (rq->curr->on_rq && test_tsk_need_resched(rq->curr)) 972 rq->skip_clock_update = 1; 973} 974 975#ifdef CONFIG_SMP 976void set_task_cpu(struct task_struct *p, unsigned int new_cpu) 977{ 978#ifdef CONFIG_SCHED_DEBUG 979 /* 980 * We should never call set_task_cpu() on a blocked task, 981 * ttwu() will sort out the placement. 982 */ 983 WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING && 984 !(task_preempt_count(p) & PREEMPT_ACTIVE)); 985 986#ifdef CONFIG_LOCKDEP 987 /* 988 * The caller should hold either p->pi_lock or rq->lock, when changing 989 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks. 990 * 991 * sched_move_task() holds both and thus holding either pins the cgroup, 992 * see task_group(). 993 * 994 * Furthermore, all task_rq users should acquire both locks, see 995 * task_rq_lock(). 996 */ 997 WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) || 998 lockdep_is_held(&task_rq(p)->lock))); 999#endif 1000#endif 1001 1002 trace_sched_migrate_task(p, new_cpu); 1003 1004 if (task_cpu(p) != new_cpu) { 1005 if (p->sched_class->migrate_task_rq) 1006 p->sched_class->migrate_task_rq(p, new_cpu); 1007 p->se.nr_migrations++; 1008 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, 1, NULL, 0); 1009 } 1010 1011 __set_task_cpu(p, new_cpu); 1012} 1013 1014static void __migrate_swap_task(struct task_struct *p, int cpu) 1015{ 1016 if (p->on_rq) { 1017 struct rq *src_rq, *dst_rq; 1018 1019 src_rq = task_rq(p); 1020 dst_rq = cpu_rq(cpu); 1021 1022 deactivate_task(src_rq, p, 0); 1023 set_task_cpu(p, cpu); 1024 activate_task(dst_rq, p, 0); 1025 check_preempt_curr(dst_rq, p, 0); 1026 } else { 1027 /* 1028 * Task isn't running anymore; make it appear like we migrated 1029 * it before it went to sleep. This means on wakeup we make the 1030 * previous cpu our targer instead of where it really is. 1031 */ 1032 p->wake_cpu = cpu; 1033 } 1034} 1035 1036struct migration_swap_arg { 1037 struct task_struct *src_task, *dst_task; 1038 int src_cpu, dst_cpu; 1039}; 1040 1041static int migrate_swap_stop(void *data) 1042{ 1043 struct migration_swap_arg *arg = data; 1044 struct rq *src_rq, *dst_rq; 1045 int ret = -EAGAIN; 1046 1047 src_rq = cpu_rq(arg->src_cpu); 1048 dst_rq = cpu_rq(arg->dst_cpu); 1049 1050 double_raw_lock(&arg->src_task->pi_lock, 1051 &arg->dst_task->pi_lock); 1052 double_rq_lock(src_rq, dst_rq); 1053 if (task_cpu(arg->dst_task) != arg->dst_cpu) 1054 goto unlock; 1055 1056 if (task_cpu(arg->src_task) != arg->src_cpu) 1057 goto unlock; 1058 1059 if (!cpumask_test_cpu(arg->dst_cpu, tsk_cpus_allowed(arg->src_task))) 1060 goto unlock; 1061 1062 if (!cpumask_test_cpu(arg->src_cpu, tsk_cpus_allowed(arg->dst_task))) 1063 goto unlock; 1064 1065 __migrate_swap_task(arg->src_task, arg->dst_cpu); 1066 __migrate_swap_task(arg->dst_task, arg->src_cpu); 1067 1068 ret = 0; 1069 1070unlock: 1071 double_rq_unlock(src_rq, dst_rq); 1072 raw_spin_unlock(&arg->dst_task->pi_lock); 1073 raw_spin_unlock(&arg->src_task->pi_lock); 1074 1075 return ret; 1076} 1077 1078/* 1079 * Cross migrate two tasks 1080 */ 1081int migrate_swap(struct task_struct *cur, struct task_struct *p) 1082{ 1083 struct migration_swap_arg arg; 1084 int ret = -EINVAL; 1085 1086 arg = (struct migration_swap_arg){ 1087 .src_task = cur, 1088 .src_cpu = task_cpu(cur), 1089 .dst_task = p, 1090 .dst_cpu = task_cpu(p), 1091 }; 1092 1093 if (arg.src_cpu == arg.dst_cpu) 1094 goto out; 1095 1096 /* 1097 * These three tests are all lockless; this is OK since all of them 1098 * will be re-checked with proper locks held further down the line. 1099 */ 1100 if (!cpu_active(arg.src_cpu) || !cpu_active(arg.dst_cpu)) 1101 goto out; 1102 1103 if (!cpumask_test_cpu(arg.dst_cpu, tsk_cpus_allowed(arg.src_task))) 1104 goto out; 1105 1106 if (!cpumask_test_cpu(arg.src_cpu, tsk_cpus_allowed(arg.dst_task))) 1107 goto out; 1108 1109 trace_sched_swap_numa(cur, arg.src_cpu, p, arg.dst_cpu); 1110 ret = stop_two_cpus(arg.dst_cpu, arg.src_cpu, migrate_swap_stop, &arg); 1111 1112out: 1113 return ret; 1114} 1115 1116struct migration_arg { 1117 struct task_struct *task; 1118 int dest_cpu; 1119}; 1120 1121static int migration_cpu_stop(void *data); 1122 1123/* 1124 * wait_task_inactive - wait for a thread to unschedule. 1125 * 1126 * If @match_state is nonzero, it's the @p->state value just checked and 1127 * not expected to change. If it changes, i.e. @p might have woken up, 1128 * then return zero. When we succeed in waiting for @p to be off its CPU, 1129 * we return a positive number (its total switch count). If a second call 1130 * a short while later returns the same number, the caller can be sure that 1131 * @p has remained unscheduled the whole time. 1132 * 1133 * The caller must ensure that the task *will* unschedule sometime soon, 1134 * else this function might spin for a *long* time. This function can't 1135 * be called with interrupts off, or it may introduce deadlock with 1136 * smp_call_function() if an IPI is sent by the same process we are 1137 * waiting to become inactive. 1138 */ 1139unsigned long wait_task_inactive(struct task_struct *p, long match_state) 1140{ 1141 unsigned long flags; 1142 int running, on_rq; 1143 unsigned long ncsw; 1144 struct rq *rq; 1145 1146 for (;;) { 1147 /* 1148 * We do the initial early heuristics without holding 1149 * any task-queue locks at all. We'll only try to get 1150 * the runqueue lock when things look like they will 1151 * work out! 1152 */ 1153 rq = task_rq(p); 1154 1155 /* 1156 * If the task is actively running on another CPU 1157 * still, just relax and busy-wait without holding 1158 * any locks. 1159 * 1160 * NOTE! Since we don't hold any locks, it's not 1161 * even sure that "rq" stays as the right runqueue! 1162 * But we don't care, since "task_running()" will 1163 * return false if the runqueue has changed and p 1164 * is actually now running somewhere else! 1165 */ 1166 while (task_running(rq, p)) { 1167 if (match_state && unlikely(p->state != match_state)) 1168 return 0; 1169 cpu_relax(); 1170 } 1171 1172 /* 1173 * Ok, time to look more closely! We need the rq 1174 * lock now, to be *sure*. If we're wrong, we'll 1175 * just go back and repeat. 1176 */ 1177 rq = task_rq_lock(p, &flags); 1178 trace_sched_wait_task(p); 1179 running = task_running(rq, p); 1180 on_rq = p->on_rq; 1181 ncsw = 0; 1182 if (!match_state || p->state == match_state) 1183 ncsw = p->nvcsw | LONG_MIN; /* sets MSB */ 1184 task_rq_unlock(rq, p, &flags); 1185 1186 /* 1187 * If it changed from the expected state, bail out now. 1188 */ 1189 if (unlikely(!ncsw)) 1190 break; 1191 1192 /* 1193 * Was it really running after all now that we 1194 * checked with the proper locks actually held? 1195 * 1196 * Oops. Go back and try again.. 1197 */ 1198 if (unlikely(running)) { 1199 cpu_relax(); 1200 continue; 1201 } 1202 1203 /* 1204 * It's not enough that it's not actively running, 1205 * it must be off the runqueue _entirely_, and not 1206 * preempted! 1207 * 1208 * So if it was still runnable (but just not actively 1209 * running right now), it's preempted, and we should 1210 * yield - it could be a while. 1211 */ 1212 if (unlikely(on_rq)) { 1213 ktime_t to = ktime_set(0, NSEC_PER_SEC/HZ); 1214 1215 set_current_state(TASK_UNINTERRUPTIBLE); 1216 schedule_hrtimeout(&to, HRTIMER_MODE_REL); 1217 continue; 1218 } 1219 1220 /* 1221 * Ahh, all good. It wasn't running, and it wasn't 1222 * runnable, which means that it will never become 1223 * running in the future either. We're all done! 1224 */ 1225 break; 1226 } 1227 1228 return ncsw; 1229} 1230 1231/*** 1232 * kick_process - kick a running thread to enter/exit the kernel 1233 * @p: the to-be-kicked thread 1234 * 1235 * Cause a process which is running on another CPU to enter 1236 * kernel-mode, without any delay. (to get signals handled.) 1237 * 1238 * NOTE: this function doesn't have to take the runqueue lock, 1239 * because all it wants to ensure is that the remote task enters 1240 * the kernel. If the IPI races and the task has been migrated 1241 * to another CPU then no harm is done and the purpose has been 1242 * achieved as well. 1243 */ 1244void kick_process(struct task_struct *p) 1245{ 1246 int cpu; 1247 1248 preempt_disable(); 1249 cpu = task_cpu(p); 1250 if ((cpu != smp_processor_id()) && task_curr(p)) 1251 smp_send_reschedule(cpu); 1252 preempt_enable(); 1253} 1254EXPORT_SYMBOL_GPL(kick_process); 1255#endif /* CONFIG_SMP */ 1256 1257#ifdef CONFIG_SMP 1258/* 1259 * ->cpus_allowed is protected by both rq->lock and p->pi_lock 1260 */ 1261static int select_fallback_rq(int cpu, struct task_struct *p) 1262{ 1263 int nid = cpu_to_node(cpu); 1264 const struct cpumask *nodemask = NULL; 1265 enum { cpuset, possible, fail } state = cpuset; 1266 int dest_cpu; 1267 1268 /* 1269 * If the node that the cpu is on has been offlined, cpu_to_node() 1270 * will return -1. There is no cpu on the node, and we should 1271 * select the cpu on the other node. 1272 */ 1273 if (nid != -1) { 1274 nodemask = cpumask_of_node(nid); 1275 1276 /* Look for allowed, online CPU in same node. */ 1277 for_each_cpu(dest_cpu, nodemask) { 1278 if (!cpu_online(dest_cpu)) 1279 continue; 1280 if (!cpu_active(dest_cpu)) 1281 continue; 1282 if (cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) 1283 return dest_cpu; 1284 } 1285 } 1286 1287 for (;;) { 1288 /* Any allowed, online CPU? */ 1289 for_each_cpu(dest_cpu, tsk_cpus_allowed(p)) { 1290 if (!cpu_online(dest_cpu)) 1291 continue; 1292 if (!cpu_active(dest_cpu)) 1293 continue; 1294 goto out; 1295 } 1296 1297 switch (state) { 1298 case cpuset: 1299 /* No more Mr. Nice Guy. */ 1300 cpuset_cpus_allowed_fallback(p); 1301 state = possible; 1302 break; 1303 1304 case possible: 1305 do_set_cpus_allowed(p, cpu_possible_mask); 1306 state = fail; 1307 break; 1308 1309 case fail: 1310 BUG(); 1311 break; 1312 } 1313 } 1314 1315out: 1316 if (state != cpuset) { 1317 /* 1318 * Don't tell them about moving exiting tasks or 1319 * kernel threads (both mm NULL), since they never 1320 * leave kernel. 1321 */ 1322 if (p->mm && printk_ratelimit()) { 1323 printk_sched("process %d (%s) no longer affine to cpu%d\n", 1324 task_pid_nr(p), p->comm, cpu); 1325 } 1326 } 1327 1328 return dest_cpu; 1329} 1330 1331/* 1332 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable. 1333 */ 1334static inline 1335int select_task_rq(struct task_struct *p, int cpu, int sd_flags, int wake_flags) 1336{ 1337 cpu = p->sched_class->select_task_rq(p, cpu, sd_flags, wake_flags); 1338 1339 /* 1340 * In order not to call set_task_cpu() on a blocking task we need 1341 * to rely on ttwu() to place the task on a valid ->cpus_allowed 1342 * cpu. 1343 * 1344 * Since this is common to all placement strategies, this lives here. 1345 * 1346 * [ this allows ->select_task() to simply return task_cpu(p) and 1347 * not worry about this generic constraint ] 1348 */ 1349 if (unlikely(!cpumask_test_cpu(cpu, tsk_cpus_allowed(p)) || 1350 !cpu_online(cpu))) 1351 cpu = select_fallback_rq(task_cpu(p), p); 1352 1353 return cpu; 1354} 1355 1356static void update_avg(u64 *avg, u64 sample) 1357{ 1358 s64 diff = sample - *avg; 1359 *avg += diff >> 3; 1360} 1361#endif 1362 1363static void 1364ttwu_stat(struct task_struct *p, int cpu, int wake_flags) 1365{ 1366#ifdef CONFIG_SCHEDSTATS 1367 struct rq *rq = this_rq(); 1368 1369#ifdef CONFIG_SMP 1370 int this_cpu = smp_processor_id(); 1371 1372 if (cpu == this_cpu) { 1373 schedstat_inc(rq, ttwu_local); 1374 schedstat_inc(p, se.statistics.nr_wakeups_local); 1375 } else { 1376 struct sched_domain *sd; 1377 1378 schedstat_inc(p, se.statistics.nr_wakeups_remote); 1379 rcu_read_lock(); 1380 for_each_domain(this_cpu, sd) { 1381 if (cpumask_test_cpu(cpu, sched_domain_span(sd))) { 1382 schedstat_inc(sd, ttwu_wake_remote); 1383 break; 1384 } 1385 } 1386 rcu_read_unlock(); 1387 } 1388 1389 if (wake_flags & WF_MIGRATED) 1390 schedstat_inc(p, se.statistics.nr_wakeups_migrate); 1391 1392#endif /* CONFIG_SMP */ 1393 1394 schedstat_inc(rq, ttwu_count); 1395 schedstat_inc(p, se.statistics.nr_wakeups); 1396 1397 if (wake_flags & WF_SYNC) 1398 schedstat_inc(p, se.statistics.nr_wakeups_sync); 1399 1400#endif /* CONFIG_SCHEDSTATS */ 1401} 1402 1403static void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags) 1404{ 1405 activate_task(rq, p, en_flags); 1406 p->on_rq = 1; 1407 1408 /* if a worker is waking up, notify workqueue */ 1409 if (p->flags & PF_WQ_WORKER) 1410 wq_worker_waking_up(p, cpu_of(rq)); 1411} 1412 1413/* 1414 * Mark the task runnable and perform wakeup-preemption. 1415 */ 1416static void 1417ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags) 1418{ 1419 check_preempt_curr(rq, p, wake_flags); 1420 trace_sched_wakeup(p, true); 1421 1422 p->state = TASK_RUNNING; 1423#ifdef CONFIG_SMP 1424 if (p->sched_class->task_woken) 1425 p->sched_class->task_woken(rq, p); 1426 1427 if (rq->idle_stamp) { 1428 u64 delta = rq_clock(rq) - rq->idle_stamp; 1429 u64 max = 2*rq->max_idle_balance_cost; 1430 1431 update_avg(&rq->avg_idle, delta); 1432 1433 if (rq->avg_idle > max) 1434 rq->avg_idle = max; 1435 1436 rq->idle_stamp = 0; 1437 } 1438#endif 1439} 1440 1441static void 1442ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags) 1443{ 1444#ifdef CONFIG_SMP 1445 if (p->sched_contributes_to_load) 1446 rq->nr_uninterruptible--; 1447#endif 1448 1449 ttwu_activate(rq, p, ENQUEUE_WAKEUP | ENQUEUE_WAKING); 1450 ttwu_do_wakeup(rq, p, wake_flags); 1451} 1452 1453/* 1454 * Called in case the task @p isn't fully descheduled from its runqueue, 1455 * in this case we must do a remote wakeup. Its a 'light' wakeup though, 1456 * since all we need to do is flip p->state to TASK_RUNNING, since 1457 * the task is still ->on_rq. 1458 */ 1459static int ttwu_remote(struct task_struct *p, int wake_flags) 1460{ 1461 struct rq *rq; 1462 int ret = 0; 1463 1464 rq = __task_rq_lock(p); 1465 if (p->on_rq) { 1466 /* check_preempt_curr() may use rq clock */ 1467 update_rq_clock(rq); 1468 ttwu_do_wakeup(rq, p, wake_flags); 1469 ret = 1; 1470 } 1471 __task_rq_unlock(rq); 1472 1473 return ret; 1474} 1475 1476#ifdef CONFIG_SMP 1477static void sched_ttwu_pending(void) 1478{ 1479 struct rq *rq = this_rq(); 1480 struct llist_node *llist = llist_del_all(&rq->wake_list); 1481 struct task_struct *p; 1482 1483 raw_spin_lock(&rq->lock); 1484 1485 while (llist) { 1486 p = llist_entry(llist, struct task_struct, wake_entry); 1487 llist = llist_next(llist); 1488 ttwu_do_activate(rq, p, 0); 1489 } 1490 1491 raw_spin_unlock(&rq->lock); 1492} 1493 1494void scheduler_ipi(void) 1495{ 1496 /* 1497 * Fold TIF_NEED_RESCHED into the preempt_count; anybody setting 1498 * TIF_NEED_RESCHED remotely (for the first time) will also send 1499 * this IPI. 1500 */ 1501 preempt_fold_need_resched(); 1502 1503 if (llist_empty(&this_rq()->wake_list) 1504 && !tick_nohz_full_cpu(smp_processor_id()) 1505 && !got_nohz_idle_kick()) 1506 return; 1507 1508 /* 1509 * Not all reschedule IPI handlers call irq_enter/irq_exit, since 1510 * traditionally all their work was done from the interrupt return 1511 * path. Now that we actually do some work, we need to make sure 1512 * we do call them. 1513 * 1514 * Some archs already do call them, luckily irq_enter/exit nest 1515 * properly. 1516 * 1517 * Arguably we should visit all archs and update all handlers, 1518 * however a fair share of IPIs are still resched only so this would 1519 * somewhat pessimize the simple resched case. 1520 */ 1521 irq_enter(); 1522 tick_nohz_full_check(); 1523 sched_ttwu_pending(); 1524 1525 /* 1526 * Check if someone kicked us for doing the nohz idle load balance. 1527 */ 1528 if (unlikely(got_nohz_idle_kick())) { 1529 this_rq()->idle_balance = 1; 1530 raise_softirq_irqoff(SCHED_SOFTIRQ); 1531 } 1532 irq_exit(); 1533} 1534 1535static void ttwu_queue_remote(struct task_struct *p, int cpu) 1536{ 1537 if (llist_add(&p->wake_entry, &cpu_rq(cpu)->wake_list)) 1538 smp_send_reschedule(cpu); 1539} 1540 1541bool cpus_share_cache(int this_cpu, int that_cpu) 1542{ 1543 return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu); 1544} 1545#endif /* CONFIG_SMP */ 1546 1547static void ttwu_queue(struct task_struct *p, int cpu) 1548{ 1549 struct rq *rq = cpu_rq(cpu); 1550 1551#if defined(CONFIG_SMP) 1552 if (sched_feat(TTWU_QUEUE) && !cpus_share_cache(smp_processor_id(), cpu)) { 1553 sched_clock_cpu(cpu); /* sync clocks x-cpu */ 1554 ttwu_queue_remote(p, cpu); 1555 return; 1556 } 1557#endif 1558 1559 raw_spin_lock(&rq->lock); 1560 ttwu_do_activate(rq, p, 0); 1561 raw_spin_unlock(&rq->lock); 1562} 1563 1564/** 1565 * try_to_wake_up - wake up a thread 1566 * @p: the thread to be awakened 1567 * @state: the mask of task states that can be woken 1568 * @wake_flags: wake modifier flags (WF_*) 1569 * 1570 * Put it on the run-queue if it's not already there. The "current" 1571 * thread is always on the run-queue (except when the actual 1572 * re-schedule is in progress), and as such you're allowed to do 1573 * the simpler "current->state = TASK_RUNNING" to mark yourself 1574 * runnable without the overhead of this. 1575 * 1576 * Return: %true if @p was woken up, %false if it was already running. 1577 * or @state didn't match @p's state. 1578 */ 1579static int 1580try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) 1581{ 1582 unsigned long flags; 1583 int cpu, success = 0; 1584 1585 /* 1586 * If we are going to wake up a thread waiting for CONDITION we 1587 * need to ensure that CONDITION=1 done by the caller can not be 1588 * reordered with p->state check below. This pairs with mb() in 1589 * set_current_state() the waiting thread does. 1590 */ 1591 smp_mb__before_spinlock(); 1592 raw_spin_lock_irqsave(&p->pi_lock, flags); 1593 if (!(p->state & state)) 1594 goto out; 1595 1596 success = 1; /* we're going to change ->state */ 1597 cpu = task_cpu(p); 1598 1599 if (p->on_rq && ttwu_remote(p, wake_flags)) 1600 goto stat; 1601 1602#ifdef CONFIG_SMP 1603 /* 1604 * If the owning (remote) cpu is still in the middle of schedule() with 1605 * this task as prev, wait until its done referencing the task. 1606 */ 1607 while (p->on_cpu) 1608 cpu_relax(); 1609 /* 1610 * Pairs with the smp_wmb() in finish_lock_switch(). 1611 */ 1612 smp_rmb(); 1613 1614 p->sched_contributes_to_load = !!task_contributes_to_load(p); 1615 p->state = TASK_WAKING; 1616 1617 if (p->sched_class->task_waking) 1618 p->sched_class->task_waking(p); 1619 1620 cpu = select_task_rq(p, p->wake_cpu, SD_BALANCE_WAKE, wake_flags); 1621 if (task_cpu(p) != cpu) { 1622 wake_flags |= WF_MIGRATED; 1623 set_task_cpu(p, cpu); 1624 } 1625#endif /* CONFIG_SMP */ 1626 1627 ttwu_queue(p, cpu); 1628stat: 1629 ttwu_stat(p, cpu, wake_flags); 1630out: 1631 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 1632 1633 return success; 1634} 1635 1636/** 1637 * try_to_wake_up_local - try to wake up a local task with rq lock held 1638 * @p: the thread to be awakened 1639 * 1640 * Put @p on the run-queue if it's not already there. The caller must 1641 * ensure that this_rq() is locked, @p is bound to this_rq() and not 1642 * the current task. 1643 */ 1644static void try_to_wake_up_local(struct task_struct *p) 1645{ 1646 struct rq *rq = task_rq(p); 1647 1648 if (WARN_ON_ONCE(rq != this_rq()) || 1649 WARN_ON_ONCE(p == current)) 1650 return; 1651 1652 lockdep_assert_held(&rq->lock); 1653 1654 if (!raw_spin_trylock(&p->pi_lock)) { 1655 raw_spin_unlock(&rq->lock); 1656 raw_spin_lock(&p->pi_lock); 1657 raw_spin_lock(&rq->lock); 1658 } 1659 1660 if (!(p->state & TASK_NORMAL)) 1661 goto out; 1662 1663 if (!p->on_rq) 1664 ttwu_activate(rq, p, ENQUEUE_WAKEUP); 1665 1666 ttwu_do_wakeup(rq, p, 0); 1667 ttwu_stat(p, smp_processor_id(), 0); 1668out: 1669 raw_spin_unlock(&p->pi_lock); 1670} 1671 1672/** 1673 * wake_up_process - Wake up a specific process 1674 * @p: The process to be woken up. 1675 * 1676 * Attempt to wake up the nominated process and move it to the set of runnable 1677 * processes. 1678 * 1679 * Return: 1 if the process was woken up, 0 if it was already running. 1680 * 1681 * It may be assumed that this function implies a write memory barrier before 1682 * changing the task state if and only if any tasks are woken up. 1683 */ 1684int wake_up_process(struct task_struct *p) 1685{ 1686 WARN_ON(task_is_stopped_or_traced(p)); 1687 return try_to_wake_up(p, TASK_NORMAL, 0); 1688} 1689EXPORT_SYMBOL(wake_up_process); 1690 1691int wake_up_state(struct task_struct *p, unsigned int state) 1692{ 1693 return try_to_wake_up(p, state, 0); 1694} 1695 1696/* 1697 * Perform scheduler related setup for a newly forked process p. 1698 * p is forked by current. 1699 * 1700 * __sched_fork() is basic setup used by init_idle() too: 1701 */ 1702static void __sched_fork(unsigned long clone_flags, struct task_struct *p) 1703{ 1704 p->on_rq = 0; 1705 1706 p->se.on_rq = 0; 1707 p->se.exec_start = 0; 1708 p->se.sum_exec_runtime = 0; 1709 p->se.prev_sum_exec_runtime = 0; 1710 p->se.nr_migrations = 0; 1711 p->se.vruntime = 0; 1712 INIT_LIST_HEAD(&p->se.group_node); 1713 1714#ifdef CONFIG_SCHEDSTATS 1715 memset(&p->se.statistics, 0, sizeof(p->se.statistics)); 1716#endif 1717 1718 RB_CLEAR_NODE(&p->dl.rb_node); 1719 hrtimer_init(&p->dl.dl_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 1720 p->dl.dl_runtime = p->dl.runtime = 0; 1721 p->dl.dl_deadline = p->dl.deadline = 0; 1722 p->dl.dl_period = 0; 1723 p->dl.flags = 0; 1724 1725 INIT_LIST_HEAD(&p->rt.run_list); 1726 1727#ifdef CONFIG_PREEMPT_NOTIFIERS 1728 INIT_HLIST_HEAD(&p->preempt_notifiers); 1729#endif 1730 1731#ifdef CONFIG_NUMA_BALANCING 1732 if (p->mm && atomic_read(&p->mm->mm_users) == 1) { 1733 p->mm->numa_next_scan = jiffies + msecs_to_jiffies(sysctl_numa_balancing_scan_delay); 1734 p->mm->numa_scan_seq = 0; 1735 } 1736 1737 if (clone_flags & CLONE_VM) 1738 p->numa_preferred_nid = current->numa_preferred_nid; 1739 else 1740 p->numa_preferred_nid = -1; 1741 1742 p->node_stamp = 0ULL; 1743 p->numa_scan_seq = p->mm ? p->mm->numa_scan_seq : 0; 1744 p->numa_scan_period = sysctl_numa_balancing_scan_delay; 1745 p->numa_work.next = &p->numa_work; 1746 p->numa_faults_memory = NULL; 1747 p->numa_faults_buffer_memory = NULL; 1748 p->last_task_numa_placement = 0; 1749 p->last_sum_exec_runtime = 0; 1750 1751 INIT_LIST_HEAD(&p->numa_entry); 1752 p->numa_group = NULL; 1753#endif /* CONFIG_NUMA_BALANCING */ 1754} 1755 1756#ifdef CONFIG_NUMA_BALANCING 1757#ifdef CONFIG_SCHED_DEBUG 1758void set_numabalancing_state(bool enabled) 1759{ 1760 if (enabled) 1761 sched_feat_set("NUMA"); 1762 else 1763 sched_feat_set("NO_NUMA"); 1764} 1765#else 1766__read_mostly bool numabalancing_enabled; 1767 1768void set_numabalancing_state(bool enabled) 1769{ 1770 numabalancing_enabled = enabled; 1771} 1772#endif /* CONFIG_SCHED_DEBUG */ 1773 1774#ifdef CONFIG_PROC_SYSCTL 1775int sysctl_numa_balancing(struct ctl_table *table, int write, 1776 void __user *buffer, size_t *lenp, loff_t *ppos) 1777{ 1778 struct ctl_table t; 1779 int err; 1780 int state = numabalancing_enabled; 1781 1782 if (write && !capable(CAP_SYS_ADMIN)) 1783 return -EPERM; 1784 1785 t = *table; 1786 t.data = &state; 1787 err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos); 1788 if (err < 0) 1789 return err; 1790 if (write) 1791 set_numabalancing_state(state); 1792 return err; 1793} 1794#endif 1795#endif 1796 1797/* 1798 * fork()/clone()-time setup: 1799 */ 1800int sched_fork(unsigned long clone_flags, struct task_struct *p) 1801{ 1802 unsigned long flags; 1803 int cpu = get_cpu(); 1804 1805 __sched_fork(clone_flags, p); 1806 /* 1807 * We mark the process as running here. This guarantees that 1808 * nobody will actually run it, and a signal or other external 1809 * event cannot wake it up and insert it on the runqueue either. 1810 */ 1811 p->state = TASK_RUNNING; 1812 1813 /* 1814 * Make sure we do not leak PI boosting priority to the child. 1815 */ 1816 p->prio = current->normal_prio; 1817 1818 /* 1819 * Revert to default priority/policy on fork if requested. 1820 */ 1821 if (unlikely(p->sched_reset_on_fork)) { 1822 if (task_has_dl_policy(p) || task_has_rt_policy(p)) { 1823 p->policy = SCHED_NORMAL; 1824 p->static_prio = NICE_TO_PRIO(0); 1825 p->rt_priority = 0; 1826 } else if (PRIO_TO_NICE(p->static_prio) < 0) 1827 p->static_prio = NICE_TO_PRIO(0); 1828 1829 p->prio = p->normal_prio = __normal_prio(p); 1830 set_load_weight(p); 1831 1832 /* 1833 * We don't need the reset flag anymore after the fork. It has 1834 * fulfilled its duty: 1835 */ 1836 p->sched_reset_on_fork = 0; 1837 } 1838 1839 if (dl_prio(p->prio)) { 1840 put_cpu(); 1841 return -EAGAIN; 1842 } else if (rt_prio(p->prio)) { 1843 p->sched_class = &rt_sched_class; 1844 } else { 1845 p->sched_class = &fair_sched_class; 1846 } 1847 1848 if (p->sched_class->task_fork) 1849 p->sched_class->task_fork(p); 1850 1851 /* 1852 * The child is not yet in the pid-hash so no cgroup attach races, 1853 * and the cgroup is pinned to this child due to cgroup_fork() 1854 * is ran before sched_fork(). 1855 * 1856 * Silence PROVE_RCU. 1857 */ 1858 raw_spin_lock_irqsave(&p->pi_lock, flags); 1859 set_task_cpu(p, cpu); 1860 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 1861 1862#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) 1863 if (likely(sched_info_on())) 1864 memset(&p->sched_info, 0, sizeof(p->sched_info)); 1865#endif 1866#if defined(CONFIG_SMP) 1867 p->on_cpu = 0; 1868#endif 1869 init_task_preempt_count(p); 1870#ifdef CONFIG_SMP 1871 plist_node_init(&p->pushable_tasks, MAX_PRIO); 1872 RB_CLEAR_NODE(&p->pushable_dl_tasks); 1873#endif 1874 1875 put_cpu(); 1876 return 0; 1877} 1878 1879unsigned long to_ratio(u64 period, u64 runtime) 1880{ 1881 if (runtime == RUNTIME_INF) 1882 return 1ULL << 20; 1883 1884 /* 1885 * Doing this here saves a lot of checks in all 1886 * the calling paths, and returning zero seems 1887 * safe for them anyway. 1888 */ 1889 if (period == 0) 1890 return 0; 1891 1892 return div64_u64(runtime << 20, period); 1893} 1894 1895#ifdef CONFIG_SMP 1896inline struct dl_bw *dl_bw_of(int i) 1897{ 1898 return &cpu_rq(i)->rd->dl_bw; 1899} 1900 1901static inline int dl_bw_cpus(int i) 1902{ 1903 struct root_domain *rd = cpu_rq(i)->rd; 1904 int cpus = 0; 1905 1906 for_each_cpu_and(i, rd->span, cpu_active_mask) 1907 cpus++; 1908 1909 return cpus; 1910} 1911#else 1912inline struct dl_bw *dl_bw_of(int i) 1913{ 1914 return &cpu_rq(i)->dl.dl_bw; 1915} 1916 1917static inline int dl_bw_cpus(int i) 1918{ 1919 return 1; 1920} 1921#endif 1922 1923static inline 1924void __dl_clear(struct dl_bw *dl_b, u64 tsk_bw) 1925{ 1926 dl_b->total_bw -= tsk_bw; 1927} 1928 1929static inline 1930void __dl_add(struct dl_bw *dl_b, u64 tsk_bw) 1931{ 1932 dl_b->total_bw += tsk_bw; 1933} 1934 1935static inline 1936bool __dl_overflow(struct dl_bw *dl_b, int cpus, u64 old_bw, u64 new_bw) 1937{ 1938 return dl_b->bw != -1 && 1939 dl_b->bw * cpus < dl_b->total_bw - old_bw + new_bw; 1940} 1941 1942/* 1943 * We must be sure that accepting a new task (or allowing changing the 1944 * parameters of an existing one) is consistent with the bandwidth 1945 * constraints. If yes, this function also accordingly updates the currently 1946 * allocated bandwidth to reflect the new situation. 1947 * 1948 * This function is called while holding p's rq->lock. 1949 */ 1950static int dl_overflow(struct task_struct *p, int policy, 1951 const struct sched_attr *attr) 1952{ 1953 1954 struct dl_bw *dl_b = dl_bw_of(task_cpu(p)); 1955 u64 period = attr->sched_period ?: attr->sched_deadline; 1956 u64 runtime = attr->sched_runtime; 1957 u64 new_bw = dl_policy(policy) ? to_ratio(period, runtime) : 0; 1958 int cpus, err = -1; 1959 1960 if (new_bw == p->dl.dl_bw) 1961 return 0; 1962 1963 /* 1964 * Either if a task, enters, leave, or stays -deadline but changes 1965 * its parameters, we may need to update accordingly the total 1966 * allocated bandwidth of the container. 1967 */ 1968 raw_spin_lock(&dl_b->lock); 1969 cpus = dl_bw_cpus(task_cpu(p)); 1970 if (dl_policy(policy) && !task_has_dl_policy(p) && 1971 !__dl_overflow(dl_b, cpus, 0, new_bw)) { 1972 __dl_add(dl_b, new_bw); 1973 err = 0; 1974 } else if (dl_policy(policy) && task_has_dl_policy(p) && 1975 !__dl_overflow(dl_b, cpus, p->dl.dl_bw, new_bw)) { 1976 __dl_clear(dl_b, p->dl.dl_bw); 1977 __dl_add(dl_b, new_bw); 1978 err = 0; 1979 } else if (!dl_policy(policy) && task_has_dl_policy(p)) { 1980 __dl_clear(dl_b, p->dl.dl_bw); 1981 err = 0; 1982 } 1983 raw_spin_unlock(&dl_b->lock); 1984 1985 return err; 1986} 1987 1988extern void init_dl_bw(struct dl_bw *dl_b); 1989 1990/* 1991 * wake_up_new_task - wake up a newly created task for the first time. 1992 * 1993 * This function will do some initial scheduler statistics housekeeping 1994 * that must be done for every newly created context, then puts the task 1995 * on the runqueue and wakes it. 1996 */ 1997void wake_up_new_task(struct task_struct *p) 1998{ 1999 unsigned long flags; 2000 struct rq *rq; 2001 2002 raw_spin_lock_irqsave(&p->pi_lock, flags); 2003#ifdef CONFIG_SMP 2004 /* 2005 * Fork balancing, do it here and not earlier because: 2006 * - cpus_allowed can change in the fork path 2007 * - any previously selected cpu might disappear through hotplug 2008 */ 2009 set_task_cpu(p, select_task_rq(p, task_cpu(p), SD_BALANCE_FORK, 0)); 2010#endif 2011 2012 /* Initialize new task's runnable average */ 2013 init_task_runnable_average(p); 2014 rq = __task_rq_lock(p); 2015 activate_task(rq, p, 0); 2016 p->on_rq = 1; 2017 trace_sched_wakeup_new(p, true); 2018 check_preempt_curr(rq, p, WF_FORK); 2019#ifdef CONFIG_SMP 2020 if (p->sched_class->task_woken) 2021 p->sched_class->task_woken(rq, p); 2022#endif 2023 task_rq_unlock(rq, p, &flags); 2024} 2025 2026#ifdef CONFIG_PREEMPT_NOTIFIERS 2027 2028/** 2029 * preempt_notifier_register - tell me when current is being preempted & rescheduled 2030 * @notifier: notifier struct to register 2031 */ 2032void preempt_notifier_register(struct preempt_notifier *notifier) 2033{ 2034 hlist_add_head(¬ifier->link, ¤t->preempt_notifiers); 2035} 2036EXPORT_SYMBOL_GPL(preempt_notifier_register); 2037 2038/** 2039 * preempt_notifier_unregister - no longer interested in preemption notifications 2040 * @notifier: notifier struct to unregister 2041 * 2042 * This is safe to call from within a preemption notifier. 2043 */ 2044void preempt_notifier_unregister(struct preempt_notifier *notifier) 2045{ 2046 hlist_del(¬ifier->link); 2047} 2048EXPORT_SYMBOL_GPL(preempt_notifier_unregister); 2049 2050static void fire_sched_in_preempt_notifiers(struct task_struct *curr) 2051{ 2052 struct preempt_notifier *notifier; 2053 2054 hlist_for_each_entry(notifier, &curr->preempt_notifiers, link) 2055 notifier->ops->sched_in(notifier, raw_smp_processor_id()); 2056} 2057 2058static void 2059fire_sched_out_preempt_notifiers(struct task_struct *curr, 2060 struct task_struct *next) 2061{ 2062 struct preempt_notifier *notifier; 2063 2064 hlist_for_each_entry(notifier, &curr->preempt_notifiers, link) 2065 notifier->ops->sched_out(notifier, next); 2066} 2067 2068#else /* !CONFIG_PREEMPT_NOTIFIERS */ 2069 2070static void fire_sched_in_preempt_notifiers(struct task_struct *curr) 2071{ 2072} 2073 2074static void 2075fire_sched_out_preempt_notifiers(struct task_struct *curr, 2076 struct task_struct *next) 2077{ 2078} 2079 2080#endif /* CONFIG_PREEMPT_NOTIFIERS */ 2081 2082/** 2083 * prepare_task_switch - prepare to switch tasks 2084 * @rq: the runqueue preparing to switch 2085 * @prev: the current task that is being switched out 2086 * @next: the task we are going to switch to. 2087 * 2088 * This is called with the rq lock held and interrupts off. It must 2089 * be paired with a subsequent finish_task_switch after the context 2090 * switch. 2091 * 2092 * prepare_task_switch sets up locking and calls architecture specific 2093 * hooks. 2094 */ 2095static inline void 2096prepare_task_switch(struct rq *rq, struct task_struct *prev, 2097 struct task_struct *next) 2098{ 2099 trace_sched_switch(prev, next); 2100 sched_info_switch(rq, prev, next); 2101 perf_event_task_sched_out(prev, next); 2102 fire_sched_out_preempt_notifiers(prev, next); 2103 prepare_lock_switch(rq, next); 2104 prepare_arch_switch(next); 2105} 2106 2107/** 2108 * finish_task_switch - clean up after a task-switch 2109 * @rq: runqueue associated with task-switch 2110 * @prev: the thread we just switched away from. 2111 * 2112 * finish_task_switch must be called after the context switch, paired 2113 * with a prepare_task_switch call before the context switch. 2114 * finish_task_switch will reconcile locking set up by prepare_task_switch, 2115 * and do any other architecture-specific cleanup actions. 2116 * 2117 * Note that we may have delayed dropping an mm in context_switch(). If 2118 * so, we finish that here outside of the runqueue lock. (Doing it 2119 * with the lock held can cause deadlocks; see schedule() for 2120 * details.) 2121 */ 2122static void finish_task_switch(struct rq *rq, struct task_struct *prev) 2123 __releases(rq->lock) 2124{ 2125 struct mm_struct *mm = rq->prev_mm; 2126 long prev_state; 2127 2128 rq->prev_mm = NULL; 2129 2130 /* 2131 * A task struct has one reference for the use as "current". 2132 * If a task dies, then it sets TASK_DEAD in tsk->state and calls 2133 * schedule one last time. The schedule call will never return, and 2134 * the scheduled task must drop that reference. 2135 * The test for TASK_DEAD must occur while the runqueue locks are 2136 * still held, otherwise prev could be scheduled on another cpu, die 2137 * there before we look at prev->state, and then the reference would 2138 * be dropped twice. 2139 * Manfred Spraul <manfred@colorfullife.com> 2140 */ 2141 prev_state = prev->state; 2142 vtime_task_switch(prev); 2143 finish_arch_switch(prev); 2144 perf_event_task_sched_in(prev, current); 2145 finish_lock_switch(rq, prev); 2146 finish_arch_post_lock_switch(); 2147 2148 fire_sched_in_preempt_notifiers(current); 2149 if (mm) 2150 mmdrop(mm); 2151 if (unlikely(prev_state == TASK_DEAD)) { 2152 if (prev->sched_class->task_dead) 2153 prev->sched_class->task_dead(prev); 2154 2155 /* 2156 * Remove function-return probe instances associated with this 2157 * task and put them back on the free list. 2158 */ 2159 kprobe_flush_task(prev); 2160 put_task_struct(prev); 2161 } 2162 2163 tick_nohz_task_switch(current); 2164} 2165 2166#ifdef CONFIG_SMP 2167 2168/* rq->lock is NOT held, but preemption is disabled */ 2169static inline void post_schedule(struct rq *rq) 2170{ 2171 if (rq->post_schedule) { 2172 unsigned long flags; 2173 2174 raw_spin_lock_irqsave(&rq->lock, flags); 2175 if (rq->curr->sched_class->post_schedule) 2176 rq->curr->sched_class->post_schedule(rq); 2177 raw_spin_unlock_irqrestore(&rq->lock, flags); 2178 2179 rq->post_schedule = 0; 2180 } 2181} 2182 2183#else 2184 2185static inline void post_schedule(struct rq *rq) 2186{ 2187} 2188 2189#endif 2190 2191/** 2192 * schedule_tail - first thing a freshly forked thread must call. 2193 * @prev: the thread we just switched away from. 2194 */ 2195asmlinkage void schedule_tail(struct task_struct *prev) 2196 __releases(rq->lock) 2197{ 2198 struct rq *rq = this_rq(); 2199 2200 finish_task_switch(rq, prev); 2201 2202 /* 2203 * FIXME: do we need to worry about rq being invalidated by the 2204 * task_switch? 2205 */ 2206 post_schedule(rq); 2207 2208#ifdef __ARCH_WANT_UNLOCKED_CTXSW 2209 /* In this case, finish_task_switch does not reenable preemption */ 2210 preempt_enable(); 2211#endif 2212 if (current->set_child_tid) 2213 put_user(task_pid_vnr(current), current->set_child_tid); 2214} 2215 2216/* 2217 * context_switch - switch to the new MM and the new 2218 * thread's register state. 2219 */ 2220static inline void 2221context_switch(struct rq *rq, struct task_struct *prev, 2222 struct task_struct *next) 2223{ 2224 struct mm_struct *mm, *oldmm; 2225 2226 prepare_task_switch(rq, prev, next); 2227 2228 mm = next->mm; 2229 oldmm = prev->active_mm; 2230 /* 2231 * For paravirt, this is coupled with an exit in switch_to to 2232 * combine the page table reload and the switch backend into 2233 * one hypercall. 2234 */ 2235 arch_start_context_switch(prev); 2236 2237 if (!mm) { 2238 next->active_mm = oldmm; 2239 atomic_inc(&oldmm->mm_count); 2240 enter_lazy_tlb(oldmm, next); 2241 } else 2242 switch_mm(oldmm, mm, next); 2243 2244 if (!prev->mm) { 2245 prev->active_mm = NULL; 2246 rq->prev_mm = oldmm; 2247 } 2248 /* 2249 * Since the runqueue lock will be released by the next 2250 * task (which is an invalid locking op but in the case 2251 * of the scheduler it's an obvious special-case), so we 2252 * do an early lockdep release here: 2253 */ 2254#ifndef __ARCH_WANT_UNLOCKED_CTXSW 2255 spin_release(&rq->lock.dep_map, 1, _THIS_IP_); 2256#endif 2257 2258 context_tracking_task_switch(prev, next); 2259 /* Here we just switch the register state and the stack. */ 2260 switch_to(prev, next, prev); 2261 2262 barrier(); 2263 /* 2264 * this_rq must be evaluated again because prev may have moved 2265 * CPUs since it called schedule(), thus the 'rq' on its stack 2266 * frame will be invalid. 2267 */ 2268 finish_task_switch(this_rq(), prev); 2269} 2270 2271/* 2272 * nr_running and nr_context_switches: 2273 * 2274 * externally visible scheduler statistics: current number of runnable 2275 * threads, total number of context switches performed since bootup. 2276 */ 2277unsigned long nr_running(void) 2278{ 2279 unsigned long i, sum = 0; 2280 2281 for_each_online_cpu(i) 2282 sum += cpu_rq(i)->nr_running; 2283 2284 return sum; 2285} 2286 2287unsigned long long nr_context_switches(void) 2288{ 2289 int i; 2290 unsigned long long sum = 0; 2291 2292 for_each_possible_cpu(i) 2293 sum += cpu_rq(i)->nr_switches; 2294 2295 return sum; 2296} 2297 2298unsigned long nr_iowait(void) 2299{ 2300 unsigned long i, sum = 0; 2301 2302 for_each_possible_cpu(i) 2303 sum += atomic_read(&cpu_rq(i)->nr_iowait); 2304 2305 return sum; 2306} 2307 2308unsigned long nr_iowait_cpu(int cpu) 2309{ 2310 struct rq *this = cpu_rq(cpu); 2311 return atomic_read(&this->nr_iowait); 2312} 2313 2314#ifdef CONFIG_SMP 2315 2316/* 2317 * sched_exec - execve() is a valuable balancing opportunity, because at 2318 * this point the task has the smallest effective memory and cache footprint. 2319 */ 2320void sched_exec(void) 2321{ 2322 struct task_struct *p = current; 2323 unsigned long flags; 2324 int dest_cpu; 2325 2326 raw_spin_lock_irqsave(&p->pi_lock, flags); 2327 dest_cpu = p->sched_class->select_task_rq(p, task_cpu(p), SD_BALANCE_EXEC, 0); 2328 if (dest_cpu == smp_processor_id()) 2329 goto unlock; 2330 2331 if (likely(cpu_active(dest_cpu))) { 2332 struct migration_arg arg = { p, dest_cpu }; 2333 2334 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 2335 stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg); 2336 return; 2337 } 2338unlock: 2339 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 2340} 2341 2342#endif 2343 2344DEFINE_PER_CPU(struct kernel_stat, kstat); 2345DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat); 2346 2347EXPORT_PER_CPU_SYMBOL(kstat); 2348EXPORT_PER_CPU_SYMBOL(kernel_cpustat); 2349 2350/* 2351 * Return any ns on the sched_clock that have not yet been accounted in 2352 * @p in case that task is currently running. 2353 * 2354 * Called with task_rq_lock() held on @rq. 2355 */ 2356static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq) 2357{ 2358 u64 ns = 0; 2359 2360 if (task_current(rq, p)) { 2361 update_rq_clock(rq); 2362 ns = rq_clock_task(rq) - p->se.exec_start; 2363 if ((s64)ns < 0) 2364 ns = 0; 2365 } 2366 2367 return ns; 2368} 2369 2370unsigned long long task_delta_exec(struct task_struct *p) 2371{ 2372 unsigned long flags; 2373 struct rq *rq; 2374 u64 ns = 0; 2375 2376 rq = task_rq_lock(p, &flags); 2377 ns = do_task_delta_exec(p, rq); 2378 task_rq_unlock(rq, p, &flags); 2379 2380 return ns; 2381} 2382 2383/* 2384 * Return accounted runtime for the task. 2385 * In case the task is currently running, return the runtime plus current's 2386 * pending runtime that have not been accounted yet. 2387 */ 2388unsigned long long task_sched_runtime(struct task_struct *p) 2389{ 2390 unsigned long flags; 2391 struct rq *rq; 2392 u64 ns = 0; 2393 2394#if defined(CONFIG_64BIT) && defined(CONFIG_SMP) 2395 /* 2396 * 64-bit doesn't need locks to atomically read a 64bit value. 2397 * So we have a optimization chance when the task's delta_exec is 0. 2398 * Reading ->on_cpu is racy, but this is ok. 2399 * 2400 * If we race with it leaving cpu, we'll take a lock. So we're correct. 2401 * If we race with it entering cpu, unaccounted time is 0. This is 2402 * indistinguishable from the read occurring a few cycles earlier. 2403 */ 2404 if (!p->on_cpu) 2405 return p->se.sum_exec_runtime; 2406#endif 2407 2408 rq = task_rq_lock(p, &flags); 2409 ns = p->se.sum_exec_runtime + do_task_delta_exec(p, rq); 2410 task_rq_unlock(rq, p, &flags); 2411 2412 return ns; 2413} 2414 2415/* 2416 * This function gets called by the timer code, with HZ frequency. 2417 * We call it with interrupts disabled. 2418 */ 2419void scheduler_tick(void) 2420{ 2421 int cpu = smp_processor_id(); 2422 struct rq *rq = cpu_rq(cpu); 2423 struct task_struct *curr = rq->curr; 2424 2425 sched_clock_tick(); 2426 2427 raw_spin_lock(&rq->lock); 2428 update_rq_clock(rq); 2429 curr->sched_class->task_tick(rq, curr, 0); 2430 update_cpu_load_active(rq); 2431 raw_spin_unlock(&rq->lock); 2432 2433 perf_event_task_tick(); 2434 2435#ifdef CONFIG_SMP 2436 rq->idle_balance = idle_cpu(cpu); 2437 trigger_load_balance(rq); 2438#endif 2439 rq_last_tick_reset(rq); 2440} 2441 2442#ifdef CONFIG_NO_HZ_FULL 2443/** 2444 * scheduler_tick_max_deferment 2445 * 2446 * Keep at least one tick per second when a single 2447 * active task is running because the scheduler doesn't 2448 * yet completely support full dynticks environment. 2449 * 2450 * This makes sure that uptime, CFS vruntime, load 2451 * balancing, etc... continue to move forward, even 2452 * with a very low granularity. 2453 * 2454 * Return: Maximum deferment in nanoseconds. 2455 */ 2456u64 scheduler_tick_max_deferment(void) 2457{ 2458 struct rq *rq = this_rq(); 2459 unsigned long next, now = ACCESS_ONCE(jiffies); 2460 2461 next = rq->last_sched_tick + HZ; 2462 2463 if (time_before_eq(next, now)) 2464 return 0; 2465 2466 return jiffies_to_nsecs(next - now); 2467} 2468#endif 2469 2470notrace unsigned long get_parent_ip(unsigned long addr) 2471{ 2472 if (in_lock_functions(addr)) { 2473 addr = CALLER_ADDR2; 2474 if (in_lock_functions(addr)) 2475 addr = CALLER_ADDR3; 2476 } 2477 return addr; 2478} 2479 2480#if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \ 2481 defined(CONFIG_PREEMPT_TRACER)) 2482 2483void __kprobes preempt_count_add(int val) 2484{ 2485#ifdef CONFIG_DEBUG_PREEMPT 2486 /* 2487 * Underflow? 2488 */ 2489 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) 2490 return; 2491#endif 2492 __preempt_count_add(val); 2493#ifdef CONFIG_DEBUG_PREEMPT 2494 /* 2495 * Spinlock count overflowing soon? 2496 */ 2497 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= 2498 PREEMPT_MASK - 10); 2499#endif 2500 if (preempt_count() == val) { 2501 unsigned long ip = get_parent_ip(CALLER_ADDR1); 2502#ifdef CONFIG_DEBUG_PREEMPT 2503 current->preempt_disable_ip = ip; 2504#endif 2505 trace_preempt_off(CALLER_ADDR0, ip); 2506 } 2507} 2508EXPORT_SYMBOL(preempt_count_add); 2509 2510void __kprobes preempt_count_sub(int val) 2511{ 2512#ifdef CONFIG_DEBUG_PREEMPT 2513 /* 2514 * Underflow? 2515 */ 2516 if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) 2517 return; 2518 /* 2519 * Is the spinlock portion underflowing? 2520 */ 2521 if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && 2522 !(preempt_count() & PREEMPT_MASK))) 2523 return; 2524#endif 2525 2526 if (preempt_count() == val) 2527 trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); 2528 __preempt_count_sub(val); 2529} 2530EXPORT_SYMBOL(preempt_count_sub); 2531 2532#endif 2533 2534/* 2535 * Print scheduling while atomic bug: 2536 */ 2537static noinline void __schedule_bug(struct task_struct *prev) 2538{ 2539 if (oops_in_progress) 2540 return; 2541 2542 printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n", 2543 prev->comm, prev->pid, preempt_count()); 2544 2545 debug_show_held_locks(prev); 2546 print_modules(); 2547 if (irqs_disabled()) 2548 print_irqtrace_events(prev); 2549#ifdef CONFIG_DEBUG_PREEMPT 2550 if (in_atomic_preempt_off()) { 2551 pr_err("Preemption disabled at:"); 2552 print_ip_sym(current->preempt_disable_ip); 2553 pr_cont("\n"); 2554 } 2555#endif 2556 dump_stack(); 2557 add_taint(TAINT_WARN, LOCKDEP_STILL_OK); 2558} 2559 2560/* 2561 * Various schedule()-time debugging checks and statistics: 2562 */ 2563static inline void schedule_debug(struct task_struct *prev) 2564{ 2565 /* 2566 * Test if we are atomic. Since do_exit() needs to call into 2567 * schedule() atomically, we ignore that path. Otherwise whine 2568 * if we are scheduling when we should not. 2569 */ 2570 if (unlikely(in_atomic_preempt_off() && prev->state != TASK_DEAD)) 2571 __schedule_bug(prev); 2572 rcu_sleep_check(); 2573 2574 profile_hit(SCHED_PROFILING, __builtin_return_address(0)); 2575 2576 schedstat_inc(this_rq(), sched_count); 2577} 2578 2579/* 2580 * Pick up the highest-prio task: 2581 */ 2582static inline struct task_struct * 2583pick_next_task(struct rq *rq, struct task_struct *prev) 2584{ 2585 const struct sched_class *class = &fair_sched_class; 2586 struct task_struct *p; 2587 2588 /* 2589 * Optimization: we know that if all tasks are in 2590 * the fair class we can call that function directly: 2591 */ 2592 if (likely(prev->sched_class == class && 2593 rq->nr_running == rq->cfs.h_nr_running)) { 2594 p = fair_sched_class.pick_next_task(rq, prev); 2595 if (unlikely(p == RETRY_TASK)) 2596 goto again; 2597 2598 /* assumes fair_sched_class->next == idle_sched_class */ 2599 if (unlikely(!p)) 2600 p = idle_sched_class.pick_next_task(rq, prev); 2601 2602 return p; 2603 } 2604 2605again: 2606 for_each_class(class) { 2607 p = class->pick_next_task(rq, prev); 2608 if (p) { 2609 if (unlikely(p == RETRY_TASK)) 2610 goto again; 2611 return p; 2612 } 2613 } 2614 2615 BUG(); /* the idle class will always have a runnable task */ 2616} 2617 2618/* 2619 * __schedule() is the main scheduler function. 2620 * 2621 * The main means of driving the scheduler and thus entering this function are: 2622 * 2623 * 1. Explicit blocking: mutex, semaphore, waitqueue, etc. 2624 * 2625 * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return 2626 * paths. For example, see arch/x86/entry_64.S. 2627 * 2628 * To drive preemption between tasks, the scheduler sets the flag in timer 2629 * interrupt handler scheduler_tick(). 2630 * 2631 * 3. Wakeups don't really cause entry into schedule(). They add a 2632 * task to the run-queue and that's it. 2633 * 2634 * Now, if the new task added to the run-queue preempts the current 2635 * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets 2636 * called on the nearest possible occasion: 2637 * 2638 * - If the kernel is preemptible (CONFIG_PREEMPT=y): 2639 * 2640 * - in syscall or exception context, at the next outmost 2641 * preempt_enable(). (this might be as soon as the wake_up()'s 2642 * spin_unlock()!) 2643 * 2644 * - in IRQ context, return from interrupt-handler to 2645 * preemptible context 2646 * 2647 * - If the kernel is not preemptible (CONFIG_PREEMPT is not set) 2648 * then at the next: 2649 * 2650 * - cond_resched() call 2651 * - explicit schedule() call 2652 * - return from syscall or exception to user-space 2653 * - return from interrupt-handler to user-space 2654 */ 2655static void __sched __schedule(void) 2656{ 2657 struct task_struct *prev, *next; 2658 unsigned long *switch_count; 2659 struct rq *rq; 2660 int cpu; 2661 2662need_resched: 2663 preempt_disable(); 2664 cpu = smp_processor_id(); 2665 rq = cpu_rq(cpu); 2666 rcu_note_context_switch(cpu); 2667 prev = rq->curr; 2668 2669 schedule_debug(prev); 2670 2671 if (sched_feat(HRTICK)) 2672 hrtick_clear(rq); 2673 2674 /* 2675 * Make sure that signal_pending_state()->signal_pending() below 2676 * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE) 2677 * done by the caller to avoid the race with signal_wake_up(). 2678 */ 2679 smp_mb__before_spinlock(); 2680 raw_spin_lock_irq(&rq->lock); 2681 2682 switch_count = &prev->nivcsw; 2683 if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { 2684 if (unlikely(signal_pending_state(prev->state, prev))) { 2685 prev->state = TASK_RUNNING; 2686 } else { 2687 deactivate_task(rq, prev, DEQUEUE_SLEEP); 2688 prev->on_rq = 0; 2689 2690 /* 2691 * If a worker went to sleep, notify and ask workqueue 2692 * whether it wants to wake up a task to maintain 2693 * concurrency. 2694 */ 2695 if (prev->flags & PF_WQ_WORKER) { 2696 struct task_struct *to_wakeup; 2697 2698 to_wakeup = wq_worker_sleeping(prev, cpu); 2699 if (to_wakeup) 2700 try_to_wake_up_local(to_wakeup); 2701 } 2702 } 2703 switch_count = &prev->nvcsw; 2704 } 2705 2706 if (prev->on_rq || rq->skip_clock_update < 0) 2707 update_rq_clock(rq); 2708 2709 next = pick_next_task(rq, prev); 2710 clear_tsk_need_resched(prev); 2711 clear_preempt_need_resched(); 2712 rq->skip_clock_update = 0; 2713 2714 if (likely(prev != next)) { 2715 rq->nr_switches++; 2716 rq->curr = next; 2717 ++*switch_count; 2718 2719 context_switch(rq, prev, next); /* unlocks the rq */ 2720 /* 2721 * The context switch have flipped the stack from under us 2722 * and restored the local variables which were saved when 2723 * this task called schedule() in the past. prev == current 2724 * is still correct, but it can be moved to another cpu/rq. 2725 */ 2726 cpu = smp_processor_id(); 2727 rq = cpu_rq(cpu); 2728 } else 2729 raw_spin_unlock_irq(&rq->lock); 2730 2731 post_schedule(rq); 2732 2733 sched_preempt_enable_no_resched(); 2734 if (need_resched()) 2735 goto need_resched; 2736} 2737 2738static inline void sched_submit_work(struct task_struct *tsk) 2739{ 2740 if (!tsk->state || tsk_is_pi_blocked(tsk)) 2741 return; 2742 /* 2743 * If we are going to sleep and we have plugged IO queued, 2744 * make sure to submit it to avoid deadlocks. 2745 */ 2746 if (blk_needs_flush_plug(tsk)) 2747 blk_schedule_flush_plug(tsk); 2748} 2749 2750asmlinkage void __sched schedule(void) 2751{ 2752 struct task_struct *tsk = current; 2753 2754 sched_submit_work(tsk); 2755 __schedule(); 2756} 2757EXPORT_SYMBOL(schedule); 2758 2759#ifdef CONFIG_CONTEXT_TRACKING 2760asmlinkage void __sched schedule_user(void) 2761{ 2762 /* 2763 * If we come here after a random call to set_need_resched(), 2764 * or we have been woken up remotely but the IPI has not yet arrived, 2765 * we haven't yet exited the RCU idle mode. Do it here manually until 2766 * we find a better solution. 2767 */ 2768 user_exit(); 2769 schedule(); 2770 user_enter(); 2771} 2772#endif 2773 2774/** 2775 * schedule_preempt_disabled - called with preemption disabled 2776 * 2777 * Returns with preemption disabled. Note: preempt_count must be 1 2778 */ 2779void __sched schedule_preempt_disabled(void) 2780{ 2781 sched_preempt_enable_no_resched(); 2782 schedule(); 2783 preempt_disable(); 2784} 2785 2786#ifdef CONFIG_PREEMPT 2787/* 2788 * this is the entry point to schedule() from in-kernel preemption 2789 * off of preempt_enable. Kernel preemptions off return from interrupt 2790 * occur there and call schedule directly. 2791 */ 2792asmlinkage void __sched notrace preempt_schedule(void) 2793{ 2794 /* 2795 * If there is a non-zero preempt_count or interrupts are disabled, 2796 * we do not want to preempt the current task. Just return.. 2797 */ 2798 if (likely(!preemptible())) 2799 return; 2800 2801 do { 2802 __preempt_count_add(PREEMPT_ACTIVE); 2803 __schedule(); 2804 __preempt_count_sub(PREEMPT_ACTIVE); 2805 2806 /* 2807 * Check again in case we missed a preemption opportunity 2808 * between schedule and now. 2809 */ 2810 barrier(); 2811 } while (need_resched()); 2812} 2813EXPORT_SYMBOL(preempt_schedule); 2814#endif /* CONFIG_PREEMPT */ 2815 2816/* 2817 * this is the entry point to schedule() from kernel preemption 2818 * off of irq context. 2819 * Note, that this is called and return with irqs disabled. This will 2820 * protect us against recursive calling from irq. 2821 */ 2822asmlinkage void __sched preempt_schedule_irq(void) 2823{ 2824 enum ctx_state prev_state; 2825 2826 /* Catch callers which need to be fixed */ 2827 BUG_ON(preempt_count() || !irqs_disabled()); 2828 2829 prev_state = exception_enter(); 2830 2831 do { 2832 __preempt_count_add(PREEMPT_ACTIVE); 2833 local_irq_enable(); 2834 __schedule(); 2835 local_irq_disable(); 2836 __preempt_count_sub(PREEMPT_ACTIVE); 2837 2838 /* 2839 * Check again in case we missed a preemption opportunity 2840 * between schedule and now. 2841 */ 2842 barrier(); 2843 } while (need_resched()); 2844 2845 exception_exit(prev_state); 2846} 2847 2848int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags, 2849 void *key) 2850{ 2851 return try_to_wake_up(curr->private, mode, wake_flags); 2852} 2853EXPORT_SYMBOL(default_wake_function); 2854 2855#ifdef CONFIG_RT_MUTEXES 2856 2857/* 2858 * rt_mutex_setprio - set the current priority of a task 2859 * @p: task 2860 * @prio: prio value (kernel-internal form) 2861 * 2862 * This function changes the 'effective' priority of a task. It does 2863 * not touch ->normal_prio like __setscheduler(). 2864 * 2865 * Used by the rt_mutex code to implement priority inheritance 2866 * logic. Call site only calls if the priority of the task changed. 2867 */ 2868void rt_mutex_setprio(struct task_struct *p, int prio) 2869{ 2870 int oldprio, on_rq, running, enqueue_flag = 0; 2871 struct rq *rq; 2872 const struct sched_class *prev_class; 2873 2874 BUG_ON(prio > MAX_PRIO); 2875 2876 rq = __task_rq_lock(p); 2877 2878 /* 2879 * Idle task boosting is a nono in general. There is one 2880 * exception, when PREEMPT_RT and NOHZ is active: 2881 * 2882 * The idle task calls get_next_timer_interrupt() and holds 2883 * the timer wheel base->lock on the CPU and another CPU wants 2884 * to access the timer (probably to cancel it). We can safely 2885 * ignore the boosting request, as the idle CPU runs this code 2886 * with interrupts disabled and will complete the lock 2887 * protected section without being interrupted. So there is no 2888 * real need to boost. 2889 */ 2890 if (unlikely(p == rq->idle)) { 2891 WARN_ON(p != rq->curr); 2892 WARN_ON(p->pi_blocked_on); 2893 goto out_unlock; 2894 } 2895 2896 trace_sched_pi_setprio(p, prio); 2897 p->pi_top_task = rt_mutex_get_top_task(p); 2898 oldprio = p->prio; 2899 prev_class = p->sched_class; 2900 on_rq = p->on_rq; 2901 running = task_current(rq, p); 2902 if (on_rq) 2903 dequeue_task(rq, p, 0); 2904 if (running) 2905 p->sched_class->put_prev_task(rq, p); 2906 2907 /* 2908 * Boosting condition are: 2909 * 1. -rt task is running and holds mutex A 2910 * --> -dl task blocks on mutex A 2911 * 2912 * 2. -dl task is running and holds mutex A 2913 * --> -dl task blocks on mutex A and could preempt the 2914 * running task 2915 */ 2916 if (dl_prio(prio)) { 2917 if (!dl_prio(p->normal_prio) || (p->pi_top_task && 2918 dl_entity_preempt(&p->pi_top_task->dl, &p->dl))) { 2919 p->dl.dl_boosted = 1; 2920 p->dl.dl_throttled = 0; 2921 enqueue_flag = ENQUEUE_REPLENISH; 2922 } else 2923 p->dl.dl_boosted = 0; 2924 p->sched_class = &dl_sched_class; 2925 } else if (rt_prio(prio)) { 2926 if (dl_prio(oldprio)) 2927 p->dl.dl_boosted = 0; 2928 if (oldprio < prio) 2929 enqueue_flag = ENQUEUE_HEAD; 2930 p->sched_class = &rt_sched_class; 2931 } else { 2932 if (dl_prio(oldprio)) 2933 p->dl.dl_boosted = 0; 2934 p->sched_class = &fair_sched_class; 2935 } 2936 2937 p->prio = prio; 2938 2939 if (running) 2940 p->sched_class->set_curr_task(rq); 2941 if (on_rq) 2942 enqueue_task(rq, p, enqueue_flag); 2943 2944 check_class_changed(rq, p, prev_class, oldprio); 2945out_unlock: 2946 __task_rq_unlock(rq); 2947} 2948#endif 2949 2950void set_user_nice(struct task_struct *p, long nice) 2951{ 2952 int old_prio, delta, on_rq; 2953 unsigned long flags; 2954 struct rq *rq; 2955 2956 if (task_nice(p) == nice || nice < MIN_NICE || nice > MAX_NICE) 2957 return; 2958 /* 2959 * We have to be careful, if called from sys_setpriority(), 2960 * the task might be in the middle of scheduling on another CPU. 2961 */ 2962 rq = task_rq_lock(p, &flags); 2963 /* 2964 * The RT priorities are set via sched_setscheduler(), but we still 2965 * allow the 'normal' nice value to be set - but as expected 2966 * it wont have any effect on scheduling until the task is 2967 * SCHED_DEADLINE, SCHED_FIFO or SCHED_RR: 2968 */ 2969 if (task_has_dl_policy(p) || task_has_rt_policy(p)) { 2970 p->static_prio = NICE_TO_PRIO(nice); 2971 goto out_unlock; 2972 } 2973 on_rq = p->on_rq; 2974 if (on_rq) 2975 dequeue_task(rq, p, 0); 2976 2977 p->static_prio = NICE_TO_PRIO(nice); 2978 set_load_weight(p); 2979 old_prio = p->prio; 2980 p->prio = effective_prio(p); 2981 delta = p->prio - old_prio; 2982 2983 if (on_rq) { 2984 enqueue_task(rq, p, 0); 2985 /* 2986 * If the task increased its priority or is running and 2987 * lowered its priority, then reschedule its CPU: 2988 */ 2989 if (delta < 0 || (delta > 0 && task_running(rq, p))) 2990 resched_task(rq->curr); 2991 } 2992out_unlock: 2993 task_rq_unlock(rq, p, &flags); 2994} 2995EXPORT_SYMBOL(set_user_nice); 2996 2997/* 2998 * can_nice - check if a task can reduce its nice value 2999 * @p: task 3000 * @nice: nice value 3001 */ 3002int can_nice(const struct task_struct *p, const int nice) 3003{ 3004 /* convert nice value [19,-20] to rlimit style value [1,40] */ 3005 int nice_rlim = 20 - nice; 3006 3007 return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) || 3008 capable(CAP_SYS_NICE)); 3009} 3010 3011#ifdef __ARCH_WANT_SYS_NICE 3012 3013/* 3014 * sys_nice - change the priority of the current process. 3015 * @increment: priority increment 3016 * 3017 * sys_setpriority is a more generic, but much slower function that 3018 * does similar things. 3019 */ 3020SYSCALL_DEFINE1(nice, int, increment) 3021{ 3022 long nice, retval; 3023 3024 /* 3025 * Setpriority might change our priority at the same moment. 3026 * We don't have to worry. Conceptually one call occurs first 3027 * and we have a single winner. 3028 */ 3029 if (increment < -40) 3030 increment = -40; 3031 if (increment > 40) 3032 increment = 40; 3033 3034 nice = task_nice(current) + increment; 3035 if (nice < MIN_NICE) 3036 nice = MIN_NICE; 3037 if (nice > MAX_NICE) 3038 nice = MAX_NICE; 3039 3040 if (increment < 0 && !can_nice(current, nice)) 3041 return -EPERM; 3042 3043 retval = security_task_setnice(current, nice); 3044 if (retval) 3045 return retval; 3046 3047 set_user_nice(current, nice); 3048 return 0; 3049} 3050 3051#endif 3052 3053/** 3054 * task_prio - return the priority value of a given task. 3055 * @p: the task in question. 3056 * 3057 * Return: The priority value as seen by users in /proc. 3058 * RT tasks are offset by -200. Normal tasks are centered 3059 * around 0, value goes from -16 to +15. 3060 */ 3061int task_prio(const struct task_struct *p) 3062{ 3063 return p->prio - MAX_RT_PRIO; 3064} 3065 3066/** 3067 * idle_cpu - is a given cpu idle currently? 3068 * @cpu: the processor in question. 3069 * 3070 * Return: 1 if the CPU is currently idle. 0 otherwise. 3071 */ 3072int idle_cpu(int cpu) 3073{ 3074 struct rq *rq = cpu_rq(cpu); 3075 3076 if (rq->curr != rq->idle) 3077 return 0; 3078 3079 if (rq->nr_running) 3080 return 0; 3081 3082#ifdef CONFIG_SMP 3083 if (!llist_empty(&rq->wake_list)) 3084 return 0; 3085#endif 3086 3087 return 1; 3088} 3089 3090/** 3091 * idle_task - return the idle task for a given cpu. 3092 * @cpu: the processor in question. 3093 * 3094 * Return: The idle task for the cpu @cpu. 3095 */ 3096struct task_struct *idle_task(int cpu) 3097{ 3098 return cpu_rq(cpu)->idle; 3099} 3100 3101/** 3102 * find_process_by_pid - find a process with a matching PID value. 3103 * @pid: the pid in question. 3104 * 3105 * The task of @pid, if found. %NULL otherwise. 3106 */ 3107static struct task_struct *find_process_by_pid(pid_t pid) 3108{ 3109 return pid ? find_task_by_vpid(pid) : current; 3110} 3111 3112/* 3113 * This function initializes the sched_dl_entity of a newly becoming 3114 * SCHED_DEADLINE task. 3115 * 3116 * Only the static values are considered here, the actual runtime and the 3117 * absolute deadline will be properly calculated when the task is enqueued 3118 * for the first time with its new policy. 3119 */ 3120static void 3121__setparam_dl(struct task_struct *p, const struct sched_attr *attr) 3122{ 3123 struct sched_dl_entity *dl_se = &p->dl; 3124 3125 init_dl_task_timer(dl_se); 3126 dl_se->dl_runtime = attr->sched_runtime; 3127 dl_se->dl_deadline = attr->sched_deadline; 3128 dl_se->dl_period = attr->sched_period ?: dl_se->dl_deadline; 3129 dl_se->flags = attr->sched_flags; 3130 dl_se->dl_bw = to_ratio(dl_se->dl_period, dl_se->dl_runtime); 3131 dl_se->dl_throttled = 0; 3132 dl_se->dl_new = 1; 3133 dl_se->dl_yielded = 0; 3134} 3135 3136static void __setscheduler_params(struct task_struct *p, 3137 const struct sched_attr *attr) 3138{ 3139 int policy = attr->sched_policy; 3140 3141 if (policy == -1) /* setparam */ 3142 policy = p->policy; 3143 3144 p->policy = policy; 3145 3146 if (dl_policy(policy)) 3147 __setparam_dl(p, attr); 3148 else if (fair_policy(policy)) 3149 p->static_prio = NICE_TO_PRIO(attr->sched_nice); 3150 3151 /* 3152 * __sched_setscheduler() ensures attr->sched_priority == 0 when 3153 * !rt_policy. Always setting this ensures that things like 3154 * getparam()/getattr() don't report silly values for !rt tasks. 3155 */ 3156 p->rt_priority = attr->sched_priority; 3157 p->normal_prio = normal_prio(p); 3158 set_load_weight(p); 3159} 3160 3161/* Actually do priority change: must hold pi & rq lock. */ 3162static void __setscheduler(struct rq *rq, struct task_struct *p, 3163 const struct sched_attr *attr) 3164{ 3165 __setscheduler_params(p, attr); 3166 3167 /* 3168 * If we get here, there was no pi waiters boosting the 3169 * task. It is safe to use the normal prio. 3170 */ 3171 p->prio = normal_prio(p); 3172 3173 if (dl_prio(p->prio)) 3174 p->sched_class = &dl_sched_class; 3175 else if (rt_prio(p->prio)) 3176 p->sched_class = &rt_sched_class; 3177 else 3178 p->sched_class = &fair_sched_class; 3179} 3180 3181static void 3182__getparam_dl(struct task_struct *p, struct sched_attr *attr) 3183{ 3184 struct sched_dl_entity *dl_se = &p->dl; 3185 3186 attr->sched_priority = p->rt_priority; 3187 attr->sched_runtime = dl_se->dl_runtime; 3188 attr->sched_deadline = dl_se->dl_deadline; 3189 attr->sched_period = dl_se->dl_period; 3190 attr->sched_flags = dl_se->flags; 3191} 3192 3193/* 3194 * This function validates the new parameters of a -deadline task. 3195 * We ask for the deadline not being zero, and greater or equal 3196 * than the runtime, as well as the period of being zero or 3197 * greater than deadline. Furthermore, we have to be sure that 3198 * user parameters are above the internal resolution (1us); we 3199 * check sched_runtime only since it is always the smaller one. 3200 */ 3201static bool 3202__checkparam_dl(const struct sched_attr *attr) 3203{ 3204 return attr && attr->sched_deadline != 0 && 3205 (attr->sched_period == 0 || 3206 (s64)(attr->sched_period - attr->sched_deadline) >= 0) && 3207 (s64)(attr->sched_deadline - attr->sched_runtime ) >= 0 && 3208 attr->sched_runtime >= (2 << (DL_SCALE - 1)); 3209} 3210 3211/* 3212 * check the target process has a UID that matches the current process's 3213 */ 3214static bool check_same_owner(struct task_struct *p) 3215{ 3216 const struct cred *cred = current_cred(), *pcred; 3217 bool match; 3218 3219 rcu_read_lock(); 3220 pcred = __task_cred(p); 3221 match = (uid_eq(cred->euid, pcred->euid) || 3222 uid_eq(cred->euid, pcred->uid)); 3223 rcu_read_unlock(); 3224 return match; 3225} 3226 3227static int __sched_setscheduler(struct task_struct *p, 3228 const struct sched_attr *attr, 3229 bool user) 3230{ 3231 int newprio = dl_policy(attr->sched_policy) ? MAX_DL_PRIO - 1 : 3232 MAX_RT_PRIO - 1 - attr->sched_priority; 3233 int retval, oldprio, oldpolicy = -1, on_rq, running; 3234 int policy = attr->sched_policy; 3235 unsigned long flags; 3236 const struct sched_class *prev_class; 3237 struct rq *rq; 3238 int reset_on_fork; 3239 3240 /* may grab non-irq protected spin_locks */ 3241 BUG_ON(in_interrupt()); 3242recheck: 3243 /* double check policy once rq lock held */ 3244 if (policy < 0) { 3245 reset_on_fork = p->sched_reset_on_fork; 3246 policy = oldpolicy = p->policy; 3247 } else { 3248 reset_on_fork = !!(attr->sched_flags & SCHED_FLAG_RESET_ON_FORK); 3249 3250 if (policy != SCHED_DEADLINE && 3251 policy != SCHED_FIFO && policy != SCHED_RR && 3252 policy != SCHED_NORMAL && policy != SCHED_BATCH && 3253 policy != SCHED_IDLE) 3254 return -EINVAL; 3255 } 3256 3257 if (attr->sched_flags & ~(SCHED_FLAG_RESET_ON_FORK)) 3258 return -EINVAL; 3259 3260 /* 3261 * Valid priorities for SCHED_FIFO and SCHED_RR are 3262 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL, 3263 * SCHED_BATCH and SCHED_IDLE is 0. 3264 */ 3265 if ((p->mm && attr->sched_priority > MAX_USER_RT_PRIO-1) || 3266 (!p->mm && attr->sched_priority > MAX_RT_PRIO-1)) 3267 return -EINVAL; 3268 if ((dl_policy(policy) && !__checkparam_dl(attr)) || 3269 (rt_policy(policy) != (attr->sched_priority != 0))) 3270 return -EINVAL; 3271 3272 /* 3273 * Allow unprivileged RT tasks to decrease priority: 3274 */ 3275 if (user && !capable(CAP_SYS_NICE)) { 3276 if (fair_policy(policy)) { 3277 if (attr->sched_nice < task_nice(p) && 3278 !can_nice(p, attr->sched_nice)) 3279 return -EPERM; 3280 } 3281 3282 if (rt_policy(policy)) { 3283 unsigned long rlim_rtprio = 3284 task_rlimit(p, RLIMIT_RTPRIO); 3285 3286 /* can't set/change the rt policy */ 3287 if (policy != p->policy && !rlim_rtprio) 3288 return -EPERM; 3289 3290 /* can't increase priority */ 3291 if (attr->sched_priority > p->rt_priority && 3292 attr->sched_priority > rlim_rtprio) 3293 return -EPERM; 3294 } 3295 3296 /* 3297 * Can't set/change SCHED_DEADLINE policy at all for now 3298 * (safest behavior); in the future we would like to allow 3299 * unprivileged DL tasks to increase their relative deadline 3300 * or reduce their runtime (both ways reducing utilization) 3301 */ 3302 if (dl_policy(policy)) 3303 return -EPERM; 3304 3305 /* 3306 * Treat SCHED_IDLE as nice 20. Only allow a switch to 3307 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it. 3308 */ 3309 if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) { 3310 if (!can_nice(p, task_nice(p))) 3311 return -EPERM; 3312 } 3313 3314 /* can't change other user's priorities */ 3315 if (!check_same_owner(p)) 3316 return -EPERM; 3317 3318 /* Normal users shall not reset the sched_reset_on_fork flag */ 3319 if (p->sched_reset_on_fork && !reset_on_fork) 3320 return -EPERM; 3321 } 3322 3323 if (user) { 3324 retval = security_task_setscheduler(p); 3325 if (retval) 3326 return retval; 3327 } 3328 3329 /* 3330 * make sure no PI-waiters arrive (or leave) while we are 3331 * changing the priority of the task: 3332 * 3333 * To be able to change p->policy safely, the appropriate 3334 * runqueue lock must be held. 3335 */ 3336 rq = task_rq_lock(p, &flags); 3337 3338 /* 3339 * Changing the policy of the stop threads its a very bad idea 3340 */ 3341 if (p == rq->stop) { 3342 task_rq_unlock(rq, p, &flags); 3343 return -EINVAL; 3344 } 3345 3346 /* 3347 * If not changing anything there's no need to proceed further, 3348 * but store a possible modification of reset_on_fork. 3349 */ 3350 if (unlikely(policy == p->policy)) { 3351 if (fair_policy(policy) && attr->sched_nice != task_nice(p)) 3352 goto change; 3353 if (rt_policy(policy) && attr->sched_priority != p->rt_priority) 3354 goto change; 3355 if (dl_policy(policy)) 3356 goto change; 3357 3358 p->sched_reset_on_fork = reset_on_fork; 3359 task_rq_unlock(rq, p, &flags); 3360 return 0; 3361 } 3362change: 3363 3364 if (user) { 3365#ifdef CONFIG_RT_GROUP_SCHED 3366 /* 3367 * Do not allow realtime tasks into groups that have no runtime 3368 * assigned. 3369 */ 3370 if (rt_bandwidth_enabled() && rt_policy(policy) && 3371 task_group(p)->rt_bandwidth.rt_runtime == 0 && 3372 !task_group_is_autogroup(task_group(p))) { 3373 task_rq_unlock(rq, p, &flags); 3374 return -EPERM; 3375 } 3376#endif 3377#ifdef CONFIG_SMP 3378 if (dl_bandwidth_enabled() && dl_policy(policy)) { 3379 cpumask_t *span = rq->rd->span; 3380 3381 /* 3382 * Don't allow tasks with an affinity mask smaller than 3383 * the entire root_domain to become SCHED_DEADLINE. We 3384 * will also fail if there's no bandwidth available. 3385 */ 3386 if (!cpumask_subset(span, &p->cpus_allowed) || 3387 rq->rd->dl_bw.bw == 0) { 3388 task_rq_unlock(rq, p, &flags); 3389 return -EPERM; 3390 } 3391 } 3392#endif 3393 } 3394 3395 /* recheck policy now with rq lock held */ 3396 if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { 3397 policy = oldpolicy = -1; 3398 task_rq_unlock(rq, p, &flags); 3399 goto recheck; 3400 } 3401 3402 /* 3403 * If setscheduling to SCHED_DEADLINE (or changing the parameters 3404 * of a SCHED_DEADLINE task) we need to check if enough bandwidth 3405 * is available. 3406 */ 3407 if ((dl_policy(policy) || dl_task(p)) && dl_overflow(p, policy, attr)) { 3408 task_rq_unlock(rq, p, &flags); 3409 return -EBUSY; 3410 } 3411 3412 p->sched_reset_on_fork = reset_on_fork; 3413 oldprio = p->prio; 3414 3415 /* 3416 * Special case for priority boosted tasks. 3417 * 3418 * If the new priority is lower or equal (user space view) 3419 * than the current (boosted) priority, we just store the new 3420 * normal parameters and do not touch the scheduler class and 3421 * the runqueue. This will be done when the task deboost 3422 * itself. 3423 */ 3424 if (rt_mutex_check_prio(p, newprio)) { 3425 __setscheduler_params(p, attr); 3426 task_rq_unlock(rq, p, &flags); 3427 return 0; 3428 } 3429 3430 on_rq = p->on_rq; 3431 running = task_current(rq, p); 3432 if (on_rq) 3433 dequeue_task(rq, p, 0); 3434 if (running) 3435 p->sched_class->put_prev_task(rq, p); 3436 3437 prev_class = p->sched_class; 3438 __setscheduler(rq, p, attr); 3439 3440 if (running) 3441 p->sched_class->set_curr_task(rq); 3442 if (on_rq) { 3443 /* 3444 * We enqueue to tail when the priority of a task is 3445 * increased (user space view). 3446 */ 3447 enqueue_task(rq, p, oldprio <= p->prio ? ENQUEUE_HEAD : 0); 3448 } 3449 3450 check_class_changed(rq, p, prev_class, oldprio); 3451 task_rq_unlock(rq, p, &flags); 3452 3453 rt_mutex_adjust_pi(p); 3454 3455 return 0; 3456} 3457 3458static int _sched_setscheduler(struct task_struct *p, int policy, 3459 const struct sched_param *param, bool check) 3460{ 3461 struct sched_attr attr = { 3462 .sched_policy = policy, 3463 .sched_priority = param->sched_priority, 3464 .sched_nice = PRIO_TO_NICE(p->static_prio), 3465 }; 3466 3467 /* 3468 * Fixup the legacy SCHED_RESET_ON_FORK hack 3469 */ 3470 if (policy & SCHED_RESET_ON_FORK) { 3471 attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK; 3472 policy &= ~SCHED_RESET_ON_FORK; 3473 attr.sched_policy = policy; 3474 } 3475 3476 return __sched_setscheduler(p, &attr, check); 3477} 3478/** 3479 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. 3480 * @p: the task in question. 3481 * @policy: new policy. 3482 * @param: structure containing the new RT priority. 3483 * 3484 * Return: 0 on success. An error code otherwise. 3485 * 3486 * NOTE that the task may be already dead. 3487 */ 3488int sched_setscheduler(struct task_struct *p, int policy, 3489 const struct sched_param *param) 3490{ 3491 return _sched_setscheduler(p, policy, param, true); 3492} 3493EXPORT_SYMBOL_GPL(sched_setscheduler); 3494 3495int sched_setattr(struct task_struct *p, const struct sched_attr *attr) 3496{ 3497 return __sched_setscheduler(p, attr, true); 3498} 3499EXPORT_SYMBOL_GPL(sched_setattr); 3500 3501/** 3502 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace. 3503 * @p: the task in question. 3504 * @policy: new policy. 3505 * @param: structure containing the new RT priority. 3506 * 3507 * Just like sched_setscheduler, only don't bother checking if the 3508 * current context has permission. For example, this is needed in 3509 * stop_machine(): we create temporary high priority worker threads, 3510 * but our caller might not have that capability. 3511 * 3512 * Return: 0 on success. An error code otherwise. 3513 */ 3514int sched_setscheduler_nocheck(struct task_struct *p, int policy, 3515 const struct sched_param *param) 3516{ 3517 return _sched_setscheduler(p, policy, param, false); 3518} 3519 3520static int 3521do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) 3522{ 3523 struct sched_param lparam; 3524 struct task_struct *p; 3525 int retval; 3526 3527 if (!param || pid < 0) 3528 return -EINVAL; 3529 if (copy_from_user(&lparam, param, sizeof(struct sched_param))) 3530 return -EFAULT; 3531 3532 rcu_read_lock(); 3533 retval = -ESRCH; 3534 p = find_process_by_pid(pid); 3535 if (p != NULL) 3536 retval = sched_setscheduler(p, policy, &lparam); 3537 rcu_read_unlock(); 3538 3539 return retval; 3540} 3541 3542/* 3543 * Mimics kernel/events/core.c perf_copy_attr(). 3544 */ 3545static int sched_copy_attr(struct sched_attr __user *uattr, 3546 struct sched_attr *attr) 3547{ 3548 u32 size; 3549 int ret; 3550 3551 if (!access_ok(VERIFY_WRITE, uattr, SCHED_ATTR_SIZE_VER0)) 3552 return -EFAULT; 3553 3554 /* 3555 * zero the full structure, so that a short copy will be nice. 3556 */ 3557 memset(attr, 0, sizeof(*attr)); 3558 3559 ret = get_user(size, &uattr->size); 3560 if (ret) 3561 return ret; 3562 3563 if (size > PAGE_SIZE) /* silly large */ 3564 goto err_size; 3565 3566 if (!size) /* abi compat */ 3567 size = SCHED_ATTR_SIZE_VER0; 3568 3569 if (size < SCHED_ATTR_SIZE_VER0) 3570 goto err_size; 3571 3572 /* 3573 * If we're handed a bigger struct than we know of, 3574 * ensure all the unknown bits are 0 - i.e. new 3575 * user-space does not rely on any kernel feature 3576 * extensions we dont know about yet. 3577 */ 3578 if (size > sizeof(*attr)) { 3579 unsigned char __user *addr; 3580 unsigned char __user *end; 3581 unsigned char val; 3582 3583 addr = (void __user *)uattr + sizeof(*attr); 3584 end = (void __user *)uattr + size; 3585 3586 for (; addr < end; addr++) { 3587 ret = get_user(val, addr); 3588 if (ret) 3589 return ret; 3590 if (val) 3591 goto err_size; 3592 } 3593 size = sizeof(*attr); 3594 } 3595 3596 ret = copy_from_user(attr, uattr, size); 3597 if (ret) 3598 return -EFAULT; 3599 3600 /* 3601 * XXX: do we want to be lenient like existing syscalls; or do we want 3602 * to be strict and return an error on out-of-bounds values? 3603 */ 3604 attr->sched_nice = clamp(attr->sched_nice, MIN_NICE, MAX_NICE); 3605 3606out: 3607 return ret; 3608 3609err_size: 3610 put_user(sizeof(*attr), &uattr->size); 3611 ret = -E2BIG; 3612 goto out; 3613} 3614 3615/** 3616 * sys_sched_setscheduler - set/change the scheduler policy and RT priority 3617 * @pid: the pid in question. 3618 * @policy: new policy. 3619 * @param: structure containing the new RT priority. 3620 * 3621 * Return: 0 on success. An error code otherwise. 3622 */ 3623SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy, 3624 struct sched_param __user *, param) 3625{ 3626 /* negative values for policy are not valid */ 3627 if (policy < 0) 3628 return -EINVAL; 3629 3630 return do_sched_setscheduler(pid, policy, param); 3631} 3632 3633/** 3634 * sys_sched_setparam - set/change the RT priority of a thread 3635 * @pid: the pid in question. 3636 * @param: structure containing the new RT priority. 3637 * 3638 * Return: 0 on success. An error code otherwise. 3639 */ 3640SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param) 3641{ 3642 return do_sched_setscheduler(pid, -1, param); 3643} 3644 3645/** 3646 * sys_sched_setattr - same as above, but with extended sched_attr 3647 * @pid: the pid in question. 3648 * @uattr: structure containing the extended parameters. 3649 * @flags: for future extension. 3650 */ 3651SYSCALL_DEFINE3(sched_setattr, pid_t, pid, struct sched_attr __user *, uattr, 3652 unsigned int, flags) 3653{ 3654 struct sched_attr attr; 3655 struct task_struct *p; 3656 int retval; 3657 3658 if (!uattr || pid < 0 || flags) 3659 return -EINVAL; 3660 3661 retval = sched_copy_attr(uattr, &attr); 3662 if (retval) 3663 return retval; 3664 3665 rcu_read_lock(); 3666 retval = -ESRCH; 3667 p = find_process_by_pid(pid); 3668 if (p != NULL) 3669 retval = sched_setattr(p, &attr); 3670 rcu_read_unlock(); 3671 3672 return retval; 3673} 3674 3675/** 3676 * sys_sched_getscheduler - get the policy (scheduling class) of a thread 3677 * @pid: the pid in question. 3678 * 3679 * Return: On success, the policy of the thread. Otherwise, a negative error 3680 * code. 3681 */ 3682SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid) 3683{ 3684 struct task_struct *p; 3685 int retval; 3686 3687 if (pid < 0) 3688 return -EINVAL; 3689 3690 retval = -ESRCH; 3691 rcu_read_lock(); 3692 p = find_process_by_pid(pid); 3693 if (p) { 3694 retval = security_task_getscheduler(p); 3695 if (!retval) 3696 retval = p->policy 3697 | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0); 3698 } 3699 rcu_read_unlock(); 3700 return retval; 3701} 3702 3703/** 3704 * sys_sched_getparam - get the RT priority of a thread 3705 * @pid: the pid in question. 3706 * @param: structure containing the RT priority. 3707 * 3708 * Return: On success, 0 and the RT priority is in @param. Otherwise, an error 3709 * code. 3710 */ 3711SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param) 3712{ 3713 struct sched_param lp; 3714 struct task_struct *p; 3715 int retval; 3716 3717 if (!param || pid < 0) 3718 return -EINVAL; 3719 3720 rcu_read_lock(); 3721 p = find_process_by_pid(pid); 3722 retval = -ESRCH; 3723 if (!p) 3724 goto out_unlock; 3725 3726 retval = security_task_getscheduler(p); 3727 if (retval) 3728 goto out_unlock; 3729 3730 if (task_has_dl_policy(p)) { 3731 retval = -EINVAL; 3732 goto out_unlock; 3733 } 3734 lp.sched_priority = p->rt_priority; 3735 rcu_read_unlock(); 3736 3737 /* 3738 * This one might sleep, we cannot do it with a spinlock held ... 3739 */ 3740 retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; 3741 3742 return retval; 3743 3744out_unlock: 3745 rcu_read_unlock(); 3746 return retval; 3747} 3748 3749static int sched_read_attr(struct sched_attr __user *uattr, 3750 struct sched_attr *attr, 3751 unsigned int usize) 3752{ 3753 int ret; 3754 3755 if (!access_ok(VERIFY_WRITE, uattr, usize)) 3756 return -EFAULT; 3757 3758 /* 3759 * If we're handed a smaller struct than we know of, 3760 * ensure all the unknown bits are 0 - i.e. old 3761 * user-space does not get uncomplete information. 3762 */ 3763 if (usize < sizeof(*attr)) { 3764 unsigned char *addr; 3765 unsigned char *end; 3766 3767 addr = (void *)attr + usize; 3768 end = (void *)attr + sizeof(*attr); 3769 3770 for (; addr < end; addr++) { 3771 if (*addr) 3772 goto err_size; 3773 } 3774 3775 attr->size = usize; 3776 } 3777 3778 ret = copy_to_user(uattr, attr, attr->size); 3779 if (ret) 3780 return -EFAULT; 3781 3782out: 3783 return ret; 3784 3785err_size: 3786 ret = -E2BIG; 3787 goto out; 3788} 3789 3790/** 3791 * sys_sched_getattr - similar to sched_getparam, but with sched_attr 3792 * @pid: the pid in question. 3793 * @uattr: structure containing the extended parameters. 3794 * @size: sizeof(attr) for fwd/bwd comp. 3795 * @flags: for future extension. 3796 */ 3797SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr, 3798 unsigned int, size, unsigned int, flags) 3799{ 3800 struct sched_attr attr = { 3801 .size = sizeof(struct sched_attr), 3802 }; 3803 struct task_struct *p; 3804 int retval; 3805 3806 if (!uattr || pid < 0 || size > PAGE_SIZE || 3807 size < SCHED_ATTR_SIZE_VER0 || flags) 3808 return -EINVAL; 3809 3810 rcu_read_lock(); 3811 p = find_process_by_pid(pid); 3812 retval = -ESRCH; 3813 if (!p) 3814 goto out_unlock; 3815 3816 retval = security_task_getscheduler(p); 3817 if (retval) 3818 goto out_unlock; 3819 3820 attr.sched_policy = p->policy; 3821 if (p->sched_reset_on_fork) 3822 attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK; 3823 if (task_has_dl_policy(p)) 3824 __getparam_dl(p, &attr); 3825 else if (task_has_rt_policy(p)) 3826 attr.sched_priority = p->rt_priority; 3827 else 3828 attr.sched_nice = task_nice(p); 3829 3830 rcu_read_unlock(); 3831 3832 retval = sched_read_attr(uattr, &attr, size); 3833 return retval; 3834 3835out_unlock: 3836 rcu_read_unlock(); 3837 return retval; 3838} 3839 3840long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) 3841{ 3842 cpumask_var_t cpus_allowed, new_mask; 3843 struct task_struct *p; 3844 int retval; 3845 3846 rcu_read_lock(); 3847 3848 p = find_process_by_pid(pid); 3849 if (!p) { 3850 rcu_read_unlock(); 3851 return -ESRCH; 3852 } 3853 3854 /* Prevent p going away */ 3855 get_task_struct(p); 3856 rcu_read_unlock(); 3857 3858 if (p->flags & PF_NO_SETAFFINITY) { 3859 retval = -EINVAL; 3860 goto out_put_task; 3861 } 3862 if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) { 3863 retval = -ENOMEM; 3864 goto out_put_task; 3865 } 3866 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) { 3867 retval = -ENOMEM; 3868 goto out_free_cpus_allowed; 3869 } 3870 retval = -EPERM; 3871 if (!check_same_owner(p)) { 3872 rcu_read_lock(); 3873 if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) { 3874 rcu_read_unlock(); 3875 goto out_unlock; 3876 } 3877 rcu_read_unlock(); 3878 } 3879 3880 retval = security_task_setscheduler(p); 3881 if (retval) 3882 goto out_unlock; 3883 3884 3885 cpuset_cpus_allowed(p, cpus_allowed); 3886 cpumask_and(new_mask, in_mask, cpus_allowed); 3887 3888 /* 3889 * Since bandwidth control happens on root_domain basis, 3890 * if admission test is enabled, we only admit -deadline 3891 * tasks allowed to run on all the CPUs in the task's 3892 * root_domain. 3893 */ 3894#ifdef CONFIG_SMP 3895 if (task_has_dl_policy(p)) { 3896 const struct cpumask *span = task_rq(p)->rd->span; 3897 3898 if (dl_bandwidth_enabled() && !cpumask_subset(span, new_mask)) { 3899 retval = -EBUSY; 3900 goto out_unlock; 3901 } 3902 } 3903#endif 3904again: 3905 retval = set_cpus_allowed_ptr(p, new_mask); 3906 3907 if (!retval) { 3908 cpuset_cpus_allowed(p, cpus_allowed); 3909 if (!cpumask_subset(new_mask, cpus_allowed)) { 3910 /* 3911 * We must have raced with a concurrent cpuset 3912 * update. Just reset the cpus_allowed to the 3913 * cpuset's cpus_allowed 3914 */ 3915 cpumask_copy(new_mask, cpus_allowed); 3916 goto again; 3917 } 3918 } 3919out_unlock: 3920 free_cpumask_var(new_mask); 3921out_free_cpus_allowed: 3922 free_cpumask_var(cpus_allowed); 3923out_put_task: 3924 put_task_struct(p); 3925 return retval; 3926} 3927 3928static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, 3929 struct cpumask *new_mask) 3930{ 3931 if (len < cpumask_size()) 3932 cpumask_clear(new_mask); 3933 else if (len > cpumask_size()) 3934 len = cpumask_size(); 3935 3936 return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; 3937} 3938 3939/** 3940 * sys_sched_setaffinity - set the cpu affinity of a process 3941 * @pid: pid of the process 3942 * @len: length in bytes of the bitmask pointed to by user_mask_ptr 3943 * @user_mask_ptr: user-space pointer to the new cpu mask 3944 * 3945 * Return: 0 on success. An error code otherwise. 3946 */ 3947SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len, 3948 unsigned long __user *, user_mask_ptr) 3949{ 3950 cpumask_var_t new_mask; 3951 int retval; 3952 3953 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) 3954 return -ENOMEM; 3955 3956 retval = get_user_cpu_mask(user_mask_ptr, len, new_mask); 3957 if (retval == 0) 3958 retval = sched_setaffinity(pid, new_mask); 3959 free_cpumask_var(new_mask); 3960 return retval; 3961} 3962 3963long sched_getaffinity(pid_t pid, struct cpumask *mask) 3964{ 3965 struct task_struct *p; 3966 unsigned long flags; 3967 int retval; 3968 3969 rcu_read_lock(); 3970 3971 retval = -ESRCH; 3972 p = find_process_by_pid(pid); 3973 if (!p) 3974 goto out_unlock; 3975 3976 retval = security_task_getscheduler(p); 3977 if (retval) 3978 goto out_unlock; 3979 3980 raw_spin_lock_irqsave(&p->pi_lock, flags); 3981 cpumask_and(mask, &p->cpus_allowed, cpu_active_mask); 3982 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 3983 3984out_unlock: 3985 rcu_read_unlock(); 3986 3987 return retval; 3988} 3989 3990/** 3991 * sys_sched_getaffinity - get the cpu affinity of a process 3992 * @pid: pid of the process 3993 * @len: length in bytes of the bitmask pointed to by user_mask_ptr 3994 * @user_mask_ptr: user-space pointer to hold the current cpu mask 3995 * 3996 * Return: 0 on success. An error code otherwise. 3997 */ 3998SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len, 3999 unsigned long __user *, user_mask_ptr) 4000{ 4001 int ret; 4002 cpumask_var_t mask; 4003 4004 if ((len * BITS_PER_BYTE) < nr_cpu_ids) 4005 return -EINVAL; 4006 if (len & (sizeof(unsigned long)-1)) 4007 return -EINVAL; 4008 4009 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) 4010 return -ENOMEM; 4011 4012 ret = sched_getaffinity(pid, mask); 4013 if (ret == 0) { 4014 size_t retlen = min_t(size_t, len, cpumask_size()); 4015 4016 if (copy_to_user(user_mask_ptr, mask, retlen)) 4017 ret = -EFAULT; 4018 else 4019 ret = retlen; 4020 } 4021 free_cpumask_var(mask); 4022 4023 return ret; 4024} 4025 4026/** 4027 * sys_sched_yield - yield the current processor to other threads. 4028 * 4029 * This function yields the current CPU to other tasks. If there are no 4030 * other threads running on this CPU then this function will return. 4031 * 4032 * Return: 0. 4033 */ 4034SYSCALL_DEFINE0(sched_yield) 4035{ 4036 struct rq *rq = this_rq_lock(); 4037 4038 schedstat_inc(rq, yld_count); 4039 current->sched_class->yield_task(rq); 4040 4041 /* 4042 * Since we are going to call schedule() anyway, there's 4043 * no need to preempt or enable interrupts: 4044 */ 4045 __release(rq->lock); 4046 spin_release(&rq->lock.dep_map, 1, _THIS_IP_); 4047 do_raw_spin_unlock(&rq->lock); 4048 sched_preempt_enable_no_resched(); 4049 4050 schedule(); 4051 4052 return 0; 4053} 4054 4055static void __cond_resched(void) 4056{ 4057 __preempt_count_add(PREEMPT_ACTIVE); 4058 __schedule(); 4059 __preempt_count_sub(PREEMPT_ACTIVE); 4060} 4061 4062int __sched _cond_resched(void) 4063{ 4064 if (should_resched()) { 4065 __cond_resched(); 4066 return 1; 4067 } 4068 return 0; 4069} 4070EXPORT_SYMBOL(_cond_resched); 4071 4072/* 4073 * __cond_resched_lock() - if a reschedule is pending, drop the given lock, 4074 * call schedule, and on return reacquire the lock. 4075 * 4076 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level 4077 * operations here to prevent schedule() from being called twice (once via 4078 * spin_unlock(), once by hand). 4079 */ 4080int __cond_resched_lock(spinlock_t *lock) 4081{ 4082 int resched = should_resched(); 4083 int ret = 0; 4084 4085 lockdep_assert_held(lock); 4086 4087 if (spin_needbreak(lock) || resched) { 4088 spin_unlock(lock); 4089 if (resched) 4090 __cond_resched(); 4091 else 4092 cpu_relax(); 4093 ret = 1; 4094 spin_lock(lock); 4095 } 4096 return ret; 4097} 4098EXPORT_SYMBOL(__cond_resched_lock); 4099 4100int __sched __cond_resched_softirq(void) 4101{ 4102 BUG_ON(!in_softirq()); 4103 4104 if (should_resched()) { 4105 local_bh_enable(); 4106 __cond_resched(); 4107 local_bh_disable(); 4108 return 1; 4109 } 4110 return 0; 4111} 4112EXPORT_SYMBOL(__cond_resched_softirq); 4113 4114/** 4115 * yield - yield the current processor to other threads. 4116 * 4117 * Do not ever use this function, there's a 99% chance you're doing it wrong. 4118 * 4119 * The scheduler is at all times free to pick the calling task as the most 4120 * eligible task to run, if removing the yield() call from your code breaks 4121 * it, its already broken. 4122 * 4123 * Typical broken usage is: 4124 * 4125 * while (!event) 4126 * yield(); 4127 * 4128 * where one assumes that yield() will let 'the other' process run that will 4129 * make event true. If the current task is a SCHED_FIFO task that will never 4130 * happen. Never use yield() as a progress guarantee!! 4131 * 4132 * If you want to use yield() to wait for something, use wait_event(). 4133 * If you want to use yield() to be 'nice' for others, use cond_resched(). 4134 * If you still want to use yield(), do not! 4135 */ 4136void __sched yield(void) 4137{ 4138 set_current_state(TASK_RUNNING); 4139 sys_sched_yield(); 4140} 4141EXPORT_SYMBOL(yield); 4142 4143/** 4144 * yield_to - yield the current processor to another thread in 4145 * your thread group, or accelerate that thread toward the 4146 * processor it's on. 4147 * @p: target task 4148 * @preempt: whether task preemption is allowed or not 4149 * 4150 * It's the caller's job to ensure that the target task struct 4151 * can't go away on us before we can do any checks. 4152 * 4153 * Return: 4154 * true (>0) if we indeed boosted the target task. 4155 * false (0) if we failed to boost the target. 4156 * -ESRCH if there's no task to yield to. 4157 */ 4158bool __sched yield_to(struct task_struct *p, bool preempt) 4159{ 4160 struct task_struct *curr = current; 4161 struct rq *rq, *p_rq; 4162 unsigned long flags; 4163 int yielded = 0; 4164 4165 local_irq_save(flags); 4166 rq = this_rq(); 4167 4168again: 4169 p_rq = task_rq(p); 4170 /* 4171 * If we're the only runnable task on the rq and target rq also 4172 * has only one task, there's absolutely no point in yielding. 4173 */ 4174 if (rq->nr_running == 1 && p_rq->nr_running == 1) { 4175 yielded = -ESRCH; 4176 goto out_irq; 4177 } 4178 4179 double_rq_lock(rq, p_rq); 4180 if (task_rq(p) != p_rq) { 4181 double_rq_unlock(rq, p_rq); 4182 goto again; 4183 } 4184 4185 if (!curr->sched_class->yield_to_task) 4186 goto out_unlock; 4187 4188 if (curr->sched_class != p->sched_class) 4189 goto out_unlock; 4190 4191 if (task_running(p_rq, p) || p->state) 4192 goto out_unlock; 4193 4194 yielded = curr->sched_class->yield_to_task(rq, p, preempt); 4195 if (yielded) { 4196 schedstat_inc(rq, yld_count); 4197 /* 4198 * Make p's CPU reschedule; pick_next_entity takes care of 4199 * fairness. 4200 */ 4201 if (preempt && rq != p_rq) 4202 resched_task(p_rq->curr); 4203 } 4204 4205out_unlock: 4206 double_rq_unlock(rq, p_rq); 4207out_irq: 4208 local_irq_restore(flags); 4209 4210 if (yielded > 0) 4211 schedule(); 4212 4213 return yielded; 4214} 4215EXPORT_SYMBOL_GPL(yield_to); 4216 4217/* 4218 * This task is about to go to sleep on IO. Increment rq->nr_iowait so 4219 * that process accounting knows that this is a task in IO wait state. 4220 */ 4221void __sched io_schedule(void) 4222{ 4223 struct rq *rq = raw_rq(); 4224 4225 delayacct_blkio_start(); 4226 atomic_inc(&rq->nr_iowait); 4227 blk_flush_plug(current); 4228 current->in_iowait = 1; 4229 schedule(); 4230 current->in_iowait = 0; 4231 atomic_dec(&rq->nr_iowait); 4232 delayacct_blkio_end(); 4233} 4234EXPORT_SYMBOL(io_schedule); 4235 4236long __sched io_schedule_timeout(long timeout) 4237{ 4238 struct rq *rq = raw_rq(); 4239 long ret; 4240 4241 delayacct_blkio_start(); 4242 atomic_inc(&rq->nr_iowait); 4243 blk_flush_plug(current); 4244 current->in_iowait = 1; 4245 ret = schedule_timeout(timeout); 4246 current->in_iowait = 0; 4247 atomic_dec(&rq->nr_iowait); 4248 delayacct_blkio_end(); 4249 return ret; 4250} 4251 4252/** 4253 * sys_sched_get_priority_max - return maximum RT priority. 4254 * @policy: scheduling class. 4255 * 4256 * Return: On success, this syscall returns the maximum 4257 * rt_priority that can be used by a given scheduling class. 4258 * On failure, a negative error code is returned. 4259 */ 4260SYSCALL_DEFINE1(sched_get_priority_max, int, policy) 4261{ 4262 int ret = -EINVAL; 4263 4264 switch (policy) { 4265 case SCHED_FIFO: 4266 case SCHED_RR: 4267 ret = MAX_USER_RT_PRIO-1; 4268 break; 4269 case SCHED_DEADLINE: 4270 case SCHED_NORMAL: 4271 case SCHED_BATCH: 4272 case SCHED_IDLE: 4273 ret = 0; 4274 break; 4275 } 4276 return ret; 4277} 4278 4279/** 4280 * sys_sched_get_priority_min - return minimum RT priority. 4281 * @policy: scheduling class. 4282 * 4283 * Return: On success, this syscall returns the minimum 4284 * rt_priority that can be used by a given scheduling class. 4285 * On failure, a negative error code is returned. 4286 */ 4287SYSCALL_DEFINE1(sched_get_priority_min, int, policy) 4288{ 4289 int ret = -EINVAL; 4290 4291 switch (policy) { 4292 case SCHED_FIFO: 4293 case SCHED_RR: 4294 ret = 1; 4295 break; 4296 case SCHED_DEADLINE: 4297 case SCHED_NORMAL: 4298 case SCHED_BATCH: 4299 case SCHED_IDLE: 4300 ret = 0; 4301 } 4302 return ret; 4303} 4304 4305/** 4306 * sys_sched_rr_get_interval - return the default timeslice of a process. 4307 * @pid: pid of the process. 4308 * @interval: userspace pointer to the timeslice value. 4309 * 4310 * this syscall writes the default timeslice value of a given process 4311 * into the user-space timespec buffer. A value of '0' means infinity. 4312 * 4313 * Return: On success, 0 and the timeslice is in @interval. Otherwise, 4314 * an error code. 4315 */ 4316SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid, 4317 struct timespec __user *, interval) 4318{ 4319 struct task_struct *p; 4320 unsigned int time_slice; 4321 unsigned long flags; 4322 struct rq *rq; 4323 int retval; 4324 struct timespec t; 4325 4326 if (pid < 0) 4327 return -EINVAL; 4328 4329 retval = -ESRCH; 4330 rcu_read_lock(); 4331 p = find_process_by_pid(pid); 4332 if (!p) 4333 goto out_unlock; 4334 4335 retval = security_task_getscheduler(p); 4336 if (retval) 4337 goto out_unlock; 4338 4339 rq = task_rq_lock(p, &flags); 4340 time_slice = 0; 4341 if (p->sched_class->get_rr_interval) 4342 time_slice = p->sched_class->get_rr_interval(rq, p); 4343 task_rq_unlock(rq, p, &flags); 4344 4345 rcu_read_unlock(); 4346 jiffies_to_timespec(time_slice, &t); 4347 retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; 4348 return retval; 4349 4350out_unlock: 4351 rcu_read_unlock(); 4352 return retval; 4353} 4354 4355static const char stat_nam[] = TASK_STATE_TO_CHAR_STR; 4356 4357void sched_show_task(struct task_struct *p) 4358{ 4359 unsigned long free = 0; 4360 int ppid; 4361 unsigned state; 4362 4363 state = p->state ? __ffs(p->state) + 1 : 0; 4364 printk(KERN_INFO "%-15.15s %c", p->comm, 4365 state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); 4366#if BITS_PER_LONG == 32 4367 if (state == TASK_RUNNING) 4368 printk(KERN_CONT " running "); 4369 else 4370 printk(KERN_CONT " %08lx ", thread_saved_pc(p)); 4371#else 4372 if (state == TASK_RUNNING) 4373 printk(KERN_CONT " running task "); 4374 else 4375 printk(KERN_CONT " %016lx ", thread_saved_pc(p)); 4376#endif 4377#ifdef CONFIG_DEBUG_STACK_USAGE 4378 free = stack_not_used(p); 4379#endif 4380 rcu_read_lock(); 4381 ppid = task_pid_nr(rcu_dereference(p->real_parent)); 4382 rcu_read_unlock(); 4383 printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free, 4384 task_pid_nr(p), ppid, 4385 (unsigned long)task_thread_info(p)->flags); 4386 4387 print_worker_info(KERN_INFO, p); 4388 show_stack(p, NULL); 4389} 4390 4391void show_state_filter(unsigned long state_filter) 4392{ 4393 struct task_struct *g, *p; 4394 4395#if BITS_PER_LONG == 32 4396 printk(KERN_INFO 4397 " task PC stack pid father\n"); 4398#else 4399 printk(KERN_INFO 4400 " task PC stack pid father\n"); 4401#endif 4402 rcu_read_lock(); 4403 do_each_thread(g, p) { 4404 /* 4405 * reset the NMI-timeout, listing all files on a slow 4406 * console might take a lot of time: 4407 */ 4408 touch_nmi_watchdog(); 4409 if (!state_filter || (p->state & state_filter)) 4410 sched_show_task(p); 4411 } while_each_thread(g, p); 4412 4413 touch_all_softlockup_watchdogs(); 4414 4415#ifdef CONFIG_SCHED_DEBUG 4416 sysrq_sched_debug_show(); 4417#endif 4418 rcu_read_unlock(); 4419 /* 4420 * Only show locks if all tasks are dumped: 4421 */ 4422 if (!state_filter) 4423 debug_show_all_locks(); 4424} 4425 4426void init_idle_bootup_task(struct task_struct *idle) 4427{ 4428 idle->sched_class = &idle_sched_class; 4429} 4430 4431/** 4432 * init_idle - set up an idle thread for a given CPU 4433 * @idle: task in question 4434 * @cpu: cpu the idle task belongs to 4435 * 4436 * NOTE: this function does not set the idle thread's NEED_RESCHED 4437 * flag, to make booting more robust. 4438 */ 4439void init_idle(struct task_struct *idle, int cpu) 4440{ 4441 struct rq *rq = cpu_rq(cpu); 4442 unsigned long flags; 4443 4444 raw_spin_lock_irqsave(&rq->lock, flags); 4445 4446 __sched_fork(0, idle); 4447 idle->state = TASK_RUNNING; 4448 idle->se.exec_start = sched_clock(); 4449 4450 do_set_cpus_allowed(idle, cpumask_of(cpu)); 4451 /* 4452 * We're having a chicken and egg problem, even though we are 4453 * holding rq->lock, the cpu isn't yet set to this cpu so the 4454 * lockdep check in task_group() will fail. 4455 * 4456 * Similar case to sched_fork(). / Alternatively we could 4457 * use task_rq_lock() here and obtain the other rq->lock. 4458 * 4459 * Silence PROVE_RCU 4460 */ 4461 rcu_read_lock(); 4462 __set_task_cpu(idle, cpu); 4463 rcu_read_unlock(); 4464 4465 rq->curr = rq->idle = idle; 4466 idle->on_rq = 1; 4467#if defined(CONFIG_SMP) 4468 idle->on_cpu = 1; 4469#endif 4470 raw_spin_unlock_irqrestore(&rq->lock, flags); 4471 4472 /* Set the preempt count _outside_ the spinlocks! */ 4473 init_idle_preempt_count(idle, cpu); 4474 4475 /* 4476 * The idle tasks have their own, simple scheduling class: 4477 */ 4478 idle->sched_class = &idle_sched_class; 4479 ftrace_graph_init_idle_task(idle, cpu); 4480 vtime_init_idle(idle, cpu); 4481#if defined(CONFIG_SMP) 4482 sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu); 4483#endif 4484} 4485 4486#ifdef CONFIG_SMP 4487void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) 4488{ 4489 if (p->sched_class && p->sched_class->set_cpus_allowed) 4490 p->sched_class->set_cpus_allowed(p, new_mask); 4491 4492 cpumask_copy(&p->cpus_allowed, new_mask); 4493 p->nr_cpus_allowed = cpumask_weight(new_mask); 4494} 4495 4496/* 4497 * This is how migration works: 4498 * 4499 * 1) we invoke migration_cpu_stop() on the target CPU using 4500 * stop_one_cpu(). 4501 * 2) stopper starts to run (implicitly forcing the migrated thread 4502 * off the CPU) 4503 * 3) it checks whether the migrated task is still in the wrong runqueue. 4504 * 4) if it's in the wrong runqueue then the migration thread removes 4505 * it and puts it into the right queue. 4506 * 5) stopper completes and stop_one_cpu() returns and the migration 4507 * is done. 4508 */ 4509 4510/* 4511 * Change a given task's CPU affinity. Migrate the thread to a 4512 * proper CPU and schedule it away if the CPU it's executing on 4513 * is removed from the allowed bitmask. 4514 * 4515 * NOTE: the caller must have a valid reference to the task, the 4516 * task must not exit() & deallocate itself prematurely. The 4517 * call is not atomic; no spinlocks may be held. 4518 */ 4519int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) 4520{ 4521 unsigned long flags; 4522 struct rq *rq; 4523 unsigned int dest_cpu; 4524 int ret = 0; 4525 4526 rq = task_rq_lock(p, &flags); 4527 4528 if (cpumask_equal(&p->cpus_allowed, new_mask)) 4529 goto out; 4530 4531 if (!cpumask_intersects(new_mask, cpu_active_mask)) { 4532 ret = -EINVAL; 4533 goto out; 4534 } 4535 4536 do_set_cpus_allowed(p, new_mask); 4537 4538 /* Can the task run on the task's current CPU? If so, we're done */ 4539 if (cpumask_test_cpu(task_cpu(p), new_mask)) 4540 goto out; 4541 4542 dest_cpu = cpumask_any_and(cpu_active_mask, new_mask); 4543 if (p->on_rq) { 4544 struct migration_arg arg = { p, dest_cpu }; 4545 /* Need help from migration thread: drop lock and wait. */ 4546 task_rq_unlock(rq, p, &flags); 4547 stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg); 4548 tlb_migrate_finish(p->mm); 4549 return 0; 4550 } 4551out: 4552 task_rq_unlock(rq, p, &flags); 4553 4554 return ret; 4555} 4556EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr); 4557 4558/* 4559 * Move (not current) task off this cpu, onto dest cpu. We're doing 4560 * this because either it can't run here any more (set_cpus_allowed() 4561 * away from this CPU, or CPU going down), or because we're 4562 * attempting to rebalance this task on exec (sched_exec). 4563 * 4564 * So we race with normal scheduler movements, but that's OK, as long 4565 * as the task is no longer on this CPU. 4566 * 4567 * Returns non-zero if task was successfully migrated. 4568 */ 4569static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) 4570{ 4571 struct rq *rq_dest, *rq_src; 4572 int ret = 0; 4573 4574 if (unlikely(!cpu_active(dest_cpu))) 4575 return ret; 4576 4577 rq_src = cpu_rq(src_cpu); 4578 rq_dest = cpu_rq(dest_cpu); 4579 4580 raw_spin_lock(&p->pi_lock); 4581 double_rq_lock(rq_src, rq_dest); 4582 /* Already moved. */ 4583 if (task_cpu(p) != src_cpu) 4584 goto done; 4585 /* Affinity changed (again). */ 4586 if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) 4587 goto fail; 4588 4589 /* 4590 * If we're not on a rq, the next wake-up will ensure we're 4591 * placed properly. 4592 */ 4593 if (p->on_rq) { 4594 dequeue_task(rq_src, p, 0); 4595 set_task_cpu(p, dest_cpu); 4596 enqueue_task(rq_dest, p, 0); 4597 check_preempt_curr(rq_dest, p, 0); 4598 } 4599done: 4600 ret = 1; 4601fail: 4602 double_rq_unlock(rq_src, rq_dest); 4603 raw_spin_unlock(&p->pi_lock); 4604 return ret; 4605} 4606 4607#ifdef CONFIG_NUMA_BALANCING 4608/* Migrate current task p to target_cpu */ 4609int migrate_task_to(struct task_struct *p, int target_cpu) 4610{ 4611 struct migration_arg arg = { p, target_cpu }; 4612 int curr_cpu = task_cpu(p); 4613 4614 if (curr_cpu == target_cpu) 4615 return 0; 4616 4617 if (!cpumask_test_cpu(target_cpu, tsk_cpus_allowed(p))) 4618 return -EINVAL; 4619 4620 /* TODO: This is not properly updating schedstats */ 4621 4622 trace_sched_move_numa(p, curr_cpu, target_cpu); 4623 return stop_one_cpu(curr_cpu, migration_cpu_stop, &arg); 4624} 4625 4626/* 4627 * Requeue a task on a given node and accurately track the number of NUMA 4628 * tasks on the runqueues 4629 */ 4630void sched_setnuma(struct task_struct *p, int nid) 4631{ 4632 struct rq *rq; 4633 unsigned long flags; 4634 bool on_rq, running; 4635 4636 rq = task_rq_lock(p, &flags); 4637 on_rq = p->on_rq; 4638 running = task_current(rq, p); 4639 4640 if (on_rq) 4641 dequeue_task(rq, p, 0); 4642 if (running) 4643 p->sched_class->put_prev_task(rq, p); 4644 4645 p->numa_preferred_nid = nid; 4646 4647 if (running) 4648 p->sched_class->set_curr_task(rq); 4649 if (on_rq) 4650 enqueue_task(rq, p, 0); 4651 task_rq_unlock(rq, p, &flags); 4652} 4653#endif 4654 4655/* 4656 * migration_cpu_stop - this will be executed by a highprio stopper thread 4657 * and performs thread migration by bumping thread off CPU then 4658 * 'pushing' onto another runqueue. 4659 */ 4660static int migration_cpu_stop(void *data) 4661{ 4662 struct migration_arg *arg = data; 4663 4664 /* 4665 * The original target cpu might have gone down and we might 4666 * be on another cpu but it doesn't matter. 4667 */ 4668 local_irq_disable(); 4669 __migrate_task(arg->task, raw_smp_processor_id(), arg->dest_cpu); 4670 local_irq_enable(); 4671 return 0; 4672} 4673 4674#ifdef CONFIG_HOTPLUG_CPU 4675 4676/* 4677 * Ensures that the idle task is using init_mm right before its cpu goes 4678 * offline. 4679 */ 4680void idle_task_exit(void) 4681{ 4682 struct mm_struct *mm = current->active_mm; 4683 4684 BUG_ON(cpu_online(smp_processor_id())); 4685 4686 if (mm != &init_mm) { 4687 switch_mm(mm, &init_mm, current); 4688 finish_arch_post_lock_switch(); 4689 } 4690 mmdrop(mm); 4691} 4692 4693/* 4694 * Since this CPU is going 'away' for a while, fold any nr_active delta 4695 * we might have. Assumes we're called after migrate_tasks() so that the 4696 * nr_active count is stable. 4697 * 4698 * Also see the comment "Global load-average calculations". 4699 */ 4700static void calc_load_migrate(struct rq *rq) 4701{ 4702 long delta = calc_load_fold_active(rq); 4703 if (delta) 4704 atomic_long_add(delta, &calc_load_tasks); 4705} 4706 4707static void put_prev_task_fake(struct rq *rq, struct task_struct *prev) 4708{ 4709} 4710 4711static const struct sched_class fake_sched_class = { 4712 .put_prev_task = put_prev_task_fake, 4713}; 4714 4715static struct task_struct fake_task = { 4716 /* 4717 * Avoid pull_{rt,dl}_task() 4718 */ 4719 .prio = MAX_PRIO + 1, 4720 .sched_class = &fake_sched_class, 4721}; 4722 4723/* 4724 * Migrate all tasks from the rq, sleeping tasks will be migrated by 4725 * try_to_wake_up()->select_task_rq(). 4726 * 4727 * Called with rq->lock held even though we'er in stop_machine() and 4728 * there's no concurrency possible, we hold the required locks anyway 4729 * because of lock validation efforts. 4730 */ 4731static void migrate_tasks(unsigned int dead_cpu) 4732{ 4733 struct rq *rq = cpu_rq(dead_cpu); 4734 struct task_struct *next, *stop = rq->stop; 4735 int dest_cpu; 4736 4737 /* 4738 * Fudge the rq selection such that the below task selection loop 4739 * doesn't get stuck on the currently eligible stop task. 4740 * 4741 * We're currently inside stop_machine() and the rq is either stuck 4742 * in the stop_machine_cpu_stop() loop, or we're executing this code, 4743 * either way we should never end up calling schedule() until we're 4744 * done here. 4745 */ 4746 rq->stop = NULL; 4747 4748 /* 4749 * put_prev_task() and pick_next_task() sched 4750 * class method both need to have an up-to-date 4751 * value of rq->clock[_task] 4752 */ 4753 update_rq_clock(rq); 4754 4755 for ( ; ; ) { 4756 /* 4757 * There's this thread running, bail when that's the only 4758 * remaining thread. 4759 */ 4760 if (rq->nr_running == 1) 4761 break; 4762 4763 next = pick_next_task(rq, &fake_task); 4764 BUG_ON(!next); 4765 next->sched_class->put_prev_task(rq, next); 4766 4767 /* Find suitable destination for @next, with force if needed. */ 4768 dest_cpu = select_fallback_rq(dead_cpu, next); 4769 raw_spin_unlock(&rq->lock); 4770 4771 __migrate_task(next, dead_cpu, dest_cpu); 4772 4773 raw_spin_lock(&rq->lock); 4774 } 4775 4776 rq->stop = stop; 4777} 4778 4779#endif /* CONFIG_HOTPLUG_CPU */ 4780 4781#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL) 4782 4783static struct ctl_table sd_ctl_dir[] = { 4784 { 4785 .procname = "sched_domain", 4786 .mode = 0555, 4787 }, 4788 {} 4789}; 4790 4791static struct ctl_table sd_ctl_root[] = { 4792 { 4793 .procname = "kernel", 4794 .mode = 0555, 4795 .child = sd_ctl_dir, 4796 }, 4797 {} 4798}; 4799 4800static struct ctl_table *sd_alloc_ctl_entry(int n) 4801{ 4802 struct ctl_table *entry = 4803 kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL); 4804 4805 return entry; 4806} 4807 4808static void sd_free_ctl_entry(struct ctl_table **tablep) 4809{ 4810 struct ctl_table *entry; 4811 4812 /* 4813 * In the intermediate directories, both the child directory and 4814 * procname are dynamically allocated and could fail but the mode 4815 * will always be set. In the lowest directory the names are 4816 * static strings and all have proc handlers. 4817 */ 4818 for (entry = *tablep; entry->mode; entry++) { 4819 if (entry->child) 4820 sd_free_ctl_entry(&entry->child); 4821 if (entry->proc_handler == NULL) 4822 kfree(entry->procname); 4823 } 4824 4825 kfree(*tablep); 4826 *tablep = NULL; 4827} 4828 4829static int min_load_idx = 0; 4830static int max_load_idx = CPU_LOAD_IDX_MAX-1; 4831 4832static void 4833set_table_entry(struct ctl_table *entry, 4834 const char *procname, void *data, int maxlen, 4835 umode_t mode, proc_handler *proc_handler, 4836 bool load_idx) 4837{ 4838 entry->procname = procname; 4839 entry->data = data; 4840 entry->maxlen = maxlen; 4841 entry->mode = mode; 4842 entry->proc_handler = proc_handler; 4843 4844 if (load_idx) { 4845 entry->extra1 = &min_load_idx; 4846 entry->extra2 = &max_load_idx; 4847 } 4848} 4849 4850static struct ctl_table * 4851sd_alloc_ctl_domain_table(struct sched_domain *sd) 4852{ 4853 struct ctl_table *table = sd_alloc_ctl_entry(14); 4854 4855 if (table == NULL) 4856 return NULL; 4857 4858 set_table_entry(&table[0], "min_interval", &sd->min_interval, 4859 sizeof(long), 0644, proc_doulongvec_minmax, false); 4860 set_table_entry(&table[1], "max_interval", &sd->max_interval, 4861 sizeof(long), 0644, proc_doulongvec_minmax, false); 4862 set_table_entry(&table[2], "busy_idx", &sd->busy_idx, 4863 sizeof(int), 0644, proc_dointvec_minmax, true); 4864 set_table_entry(&table[3], "idle_idx", &sd->idle_idx, 4865 sizeof(int), 0644, proc_dointvec_minmax, true); 4866 set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx, 4867 sizeof(int), 0644, proc_dointvec_minmax, true); 4868 set_table_entry(&table[5], "wake_idx", &sd->wake_idx, 4869 sizeof(int), 0644, proc_dointvec_minmax, true); 4870 set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx, 4871 sizeof(int), 0644, proc_dointvec_minmax, true); 4872 set_table_entry(&table[7], "busy_factor", &sd->busy_factor, 4873 sizeof(int), 0644, proc_dointvec_minmax, false); 4874 set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct, 4875 sizeof(int), 0644, proc_dointvec_minmax, false); 4876 set_table_entry(&table[9], "cache_nice_tries", 4877 &sd->cache_nice_tries, 4878 sizeof(int), 0644, proc_dointvec_minmax, false); 4879 set_table_entry(&table[10], "flags", &sd->flags, 4880 sizeof(int), 0644, proc_dointvec_minmax, false); 4881 set_table_entry(&table[11], "max_newidle_lb_cost", 4882 &sd->max_newidle_lb_cost, 4883 sizeof(long), 0644, proc_doulongvec_minmax, false); 4884 set_table_entry(&table[12], "name", sd->name, 4885 CORENAME_MAX_SIZE, 0444, proc_dostring, false); 4886 /* &table[13] is terminator */ 4887 4888 return table; 4889} 4890 4891static struct ctl_table *sd_alloc_ctl_cpu_table(int cpu) 4892{ 4893 struct ctl_table *entry, *table; 4894 struct sched_domain *sd; 4895 int domain_num = 0, i; 4896 char buf[32]; 4897 4898 for_each_domain(cpu, sd) 4899 domain_num++; 4900 entry = table = sd_alloc_ctl_entry(domain_num + 1); 4901 if (table == NULL) 4902 return NULL; 4903 4904 i = 0; 4905 for_each_domain(cpu, sd) { 4906 snprintf(buf, 32, "domain%d", i); 4907 entry->procname = kstrdup(buf, GFP_KERNEL); 4908 entry->mode = 0555; 4909 entry->child = sd_alloc_ctl_domain_table(sd); 4910 entry++; 4911 i++; 4912 } 4913 return table; 4914} 4915 4916static struct ctl_table_header *sd_sysctl_header; 4917static void register_sched_domain_sysctl(void) 4918{ 4919 int i, cpu_num = num_possible_cpus(); 4920 struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1); 4921 char buf[32]; 4922 4923 WARN_ON(sd_ctl_dir[0].child); 4924 sd_ctl_dir[0].child = entry; 4925 4926 if (entry == NULL) 4927 return; 4928 4929 for_each_possible_cpu(i) { 4930 snprintf(buf, 32, "cpu%d", i); 4931 entry->procname = kstrdup(buf, GFP_KERNEL); 4932 entry->mode = 0555; 4933 entry->child = sd_alloc_ctl_cpu_table(i); 4934 entry++; 4935 } 4936 4937 WARN_ON(sd_sysctl_header); 4938 sd_sysctl_header = register_sysctl_table(sd_ctl_root); 4939} 4940 4941/* may be called multiple times per register */ 4942static void unregister_sched_domain_sysctl(void) 4943{ 4944 if (sd_sysctl_header) 4945 unregister_sysctl_table(sd_sysctl_header); 4946 sd_sysctl_header = NULL; 4947 if (sd_ctl_dir[0].child) 4948 sd_free_ctl_entry(&sd_ctl_dir[0].child); 4949} 4950#else 4951static void register_sched_domain_sysctl(void) 4952{ 4953} 4954static void unregister_sched_domain_sysctl(void) 4955{ 4956} 4957#endif 4958 4959static void set_rq_online(struct rq *rq) 4960{ 4961 if (!rq->online) { 4962 const struct sched_class *class; 4963 4964 cpumask_set_cpu(rq->cpu, rq->rd->online); 4965 rq->online = 1; 4966 4967 for_each_class(class) { 4968 if (class->rq_online) 4969 class->rq_online(rq); 4970 } 4971 } 4972} 4973 4974static void set_rq_offline(struct rq *rq) 4975{ 4976 if (rq->online) { 4977 const struct sched_class *class; 4978 4979 for_each_class(class) { 4980 if (class->rq_offline) 4981 class->rq_offline(rq); 4982 } 4983 4984 cpumask_clear_cpu(rq->cpu, rq->rd->online); 4985 rq->online = 0; 4986 } 4987} 4988 4989/* 4990 * migration_call - callback that gets triggered when a CPU is added. 4991 * Here we can start up the necessary migration thread for the new CPU. 4992 */ 4993static int 4994migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) 4995{ 4996 int cpu = (long)hcpu; 4997 unsigned long flags; 4998 struct rq *rq = cpu_rq(cpu); 4999 5000 switch (action & ~CPU_TASKS_FROZEN) { 5001 5002 case CPU_UP_PREPARE: 5003 rq->calc_load_update = calc_load_update; 5004 break; 5005 5006 case CPU_ONLINE: 5007 /* Update our root-domain */ 5008 raw_spin_lock_irqsave(&rq->lock, flags); 5009 if (rq->rd) { 5010 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); 5011 5012 set_rq_online(rq); 5013 } 5014 raw_spin_unlock_irqrestore(&rq->lock, flags); 5015 break; 5016 5017#ifdef CONFIG_HOTPLUG_CPU 5018 case CPU_DYING: 5019 sched_ttwu_pending(); 5020 /* Update our root-domain */ 5021 raw_spin_lock_irqsave(&rq->lock, flags); 5022 if (rq->rd) { 5023 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); 5024 set_rq_offline(rq); 5025 } 5026 migrate_tasks(cpu); 5027 BUG_ON(rq->nr_running != 1); /* the migration thread */ 5028 raw_spin_unlock_irqrestore(&rq->lock, flags); 5029 break; 5030 5031 case CPU_DEAD: 5032 calc_load_migrate(rq); 5033 break; 5034#endif 5035 } 5036 5037 update_max_interval(); 5038 5039 return NOTIFY_OK; 5040} 5041 5042/* 5043 * Register at high priority so that task migration (migrate_all_tasks) 5044 * happens before everything else. This has to be lower priority than 5045 * the notifier in the perf_event subsystem, though. 5046 */ 5047static struct notifier_block migration_notifier = { 5048 .notifier_call = migration_call, 5049 .priority = CPU_PRI_MIGRATION, 5050}; 5051 5052static int sched_cpu_active(struct notifier_block *nfb, 5053 unsigned long action, void *hcpu) 5054{ 5055 switch (action & ~CPU_TASKS_FROZEN) { 5056 case CPU_STARTING: 5057 case CPU_DOWN_FAILED: 5058 set_cpu_active((long)hcpu, true); 5059 return NOTIFY_OK; 5060 default: 5061 return NOTIFY_DONE; 5062 } 5063} 5064 5065static int sched_cpu_inactive(struct notifier_block *nfb, 5066 unsigned long action, void *hcpu) 5067{ 5068 unsigned long flags; 5069 long cpu = (long)hcpu; 5070 5071 switch (action & ~CPU_TASKS_FROZEN) { 5072 case CPU_DOWN_PREPARE: 5073 set_cpu_active(cpu, false); 5074 5075 /* explicitly allow suspend */ 5076 if (!(action & CPU_TASKS_FROZEN)) { 5077 struct dl_bw *dl_b = dl_bw_of(cpu); 5078 bool overflow; 5079 int cpus; 5080 5081 raw_spin_lock_irqsave(&dl_b->lock, flags); 5082 cpus = dl_bw_cpus(cpu); 5083 overflow = __dl_overflow(dl_b, cpus, 0, 0); 5084 raw_spin_unlock_irqrestore(&dl_b->lock, flags); 5085 5086 if (overflow) 5087 return notifier_from_errno(-EBUSY); 5088 } 5089 return NOTIFY_OK; 5090 } 5091 5092 return NOTIFY_DONE; 5093} 5094 5095static int __init migration_init(void) 5096{ 5097 void *cpu = (void *)(long)smp_processor_id(); 5098 int err; 5099 5100 /* Initialize migration for the boot CPU */ 5101 err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); 5102 BUG_ON(err == NOTIFY_BAD); 5103 migration_call(&migration_notifier, CPU_ONLINE, cpu); 5104 register_cpu_notifier(&migration_notifier); 5105 5106 /* Register cpu active notifiers */ 5107 cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE); 5108 cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE); 5109 5110 return 0; 5111} 5112early_initcall(migration_init); 5113#endif 5114 5115#ifdef CONFIG_SMP 5116 5117static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */ 5118 5119#ifdef CONFIG_SCHED_DEBUG 5120 5121static __read_mostly int sched_debug_enabled; 5122 5123static int __init sched_debug_setup(char *str) 5124{ 5125 sched_debug_enabled = 1; 5126 5127 return 0; 5128} 5129early_param("sched_debug", sched_debug_setup); 5130 5131static inline bool sched_debug(void) 5132{ 5133 return sched_debug_enabled; 5134} 5135 5136static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, 5137 struct cpumask *groupmask) 5138{ 5139 struct sched_group *group = sd->groups; 5140 char str[256]; 5141 5142 cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd)); 5143 cpumask_clear(groupmask); 5144 5145 printk(KERN_DEBUG "%*s domain %d: ", level, "", level); 5146 5147 if (!(sd->flags & SD_LOAD_BALANCE)) { 5148 printk("does not load-balance\n"); 5149 if (sd->parent) 5150 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain" 5151 " has parent"); 5152 return -1; 5153 } 5154 5155 printk(KERN_CONT "span %s level %s\n", str, sd->name); 5156 5157 if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) { 5158 printk(KERN_ERR "ERROR: domain->span does not contain " 5159 "CPU%d\n", cpu); 5160 } 5161 if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) { 5162 printk(KERN_ERR "ERROR: domain->groups does not contain" 5163 " CPU%d\n", cpu); 5164 } 5165 5166 printk(KERN_DEBUG "%*s groups:", level + 1, ""); 5167 do { 5168 if (!group) { 5169 printk("\n"); 5170 printk(KERN_ERR "ERROR: group is NULL\n"); 5171 break; 5172 } 5173 5174 /* 5175 * Even though we initialize ->power to something semi-sane, 5176 * we leave power_orig unset. This allows us to detect if 5177 * domain iteration is still funny without causing /0 traps. 5178 */ 5179 if (!group->sgp->power_orig) { 5180 printk(KERN_CONT "\n"); 5181 printk(KERN_ERR "ERROR: domain->cpu_power not " 5182 "set\n"); 5183 break; 5184 } 5185 5186 if (!cpumask_weight(sched_group_cpus(group))) { 5187 printk(KERN_CONT "\n"); 5188 printk(KERN_ERR "ERROR: empty group\n"); 5189 break; 5190 } 5191 5192 if (!(sd->flags & SD_OVERLAP) && 5193 cpumask_intersects(groupmask, sched_group_cpus(group))) { 5194 printk(KERN_CONT "\n"); 5195 printk(KERN_ERR "ERROR: repeated CPUs\n"); 5196 break; 5197 } 5198 5199 cpumask_or(groupmask, groupmask, sched_group_cpus(group)); 5200 5201 cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group)); 5202 5203 printk(KERN_CONT " %s", str); 5204 if (group->sgp->power != SCHED_POWER_SCALE) { 5205 printk(KERN_CONT " (cpu_power = %d)", 5206 group->sgp->power); 5207 } 5208 5209 group = group->next; 5210 } while (group != sd->groups); 5211 printk(KERN_CONT "\n"); 5212 5213 if (!cpumask_equal(sched_domain_span(sd), groupmask)) 5214 printk(KERN_ERR "ERROR: groups don't span domain->span\n"); 5215 5216 if (sd->parent && 5217 !cpumask_subset(groupmask, sched_domain_span(sd->parent))) 5218 printk(KERN_ERR "ERROR: parent span is not a superset " 5219 "of domain->span\n"); 5220 return 0; 5221} 5222 5223static void sched_domain_debug(struct sched_domain *sd, int cpu) 5224{ 5225 int level = 0; 5226 5227 if (!sched_debug_enabled) 5228 return; 5229 5230 if (!sd) { 5231 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); 5232 return; 5233 } 5234 5235 printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); 5236 5237 for (;;) { 5238 if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask)) 5239 break; 5240 level++; 5241 sd = sd->parent; 5242 if (!sd) 5243 break; 5244 } 5245} 5246#else /* !CONFIG_SCHED_DEBUG */ 5247# define sched_domain_debug(sd, cpu) do { } while (0) 5248static inline bool sched_debug(void) 5249{ 5250 return false; 5251} 5252#endif /* CONFIG_SCHED_DEBUG */ 5253 5254static int sd_degenerate(struct sched_domain *sd) 5255{ 5256 if (cpumask_weight(sched_domain_span(sd)) == 1) 5257 return 1; 5258 5259 /* Following flags need at least 2 groups */ 5260 if (sd->flags & (SD_LOAD_BALANCE | 5261 SD_BALANCE_NEWIDLE | 5262 SD_BALANCE_FORK | 5263 SD_BALANCE_EXEC | 5264 SD_SHARE_CPUPOWER | 5265 SD_SHARE_PKG_RESOURCES)) { 5266 if (sd->groups != sd->groups->next) 5267 return 0; 5268 } 5269 5270 /* Following flags don't use groups */ 5271 if (sd->flags & (SD_WAKE_AFFINE)) 5272 return 0; 5273 5274 return 1; 5275} 5276 5277static int 5278sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) 5279{ 5280 unsigned long cflags = sd->flags, pflags = parent->flags; 5281 5282 if (sd_degenerate(parent)) 5283 return 1; 5284 5285 if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent))) 5286 return 0; 5287 5288 /* Flags needing groups don't count if only 1 group in parent */ 5289 if (parent->groups == parent->groups->next) { 5290 pflags &= ~(SD_LOAD_BALANCE | 5291 SD_BALANCE_NEWIDLE | 5292 SD_BALANCE_FORK | 5293 SD_BALANCE_EXEC | 5294 SD_SHARE_CPUPOWER | 5295 SD_SHARE_PKG_RESOURCES | 5296 SD_PREFER_SIBLING); 5297 if (nr_node_ids == 1) 5298 pflags &= ~SD_SERIALIZE; 5299 } 5300 if (~cflags & pflags) 5301 return 0; 5302 5303 return 1; 5304} 5305 5306static void free_rootdomain(struct rcu_head *rcu) 5307{ 5308 struct root_domain *rd = container_of(rcu, struct root_domain, rcu); 5309 5310 cpupri_cleanup(&rd->cpupri); 5311 cpudl_cleanup(&rd->cpudl); 5312 free_cpumask_var(rd->dlo_mask); 5313 free_cpumask_var(rd->rto_mask); 5314 free_cpumask_var(rd->online); 5315 free_cpumask_var(rd->span); 5316 kfree(rd); 5317} 5318 5319static void rq_attach_root(struct rq *rq, struct root_domain *rd) 5320{ 5321 struct root_domain *old_rd = NULL; 5322 unsigned long flags; 5323 5324 raw_spin_lock_irqsave(&rq->lock, flags); 5325 5326 if (rq->rd) { 5327 old_rd = rq->rd; 5328 5329 if (cpumask_test_cpu(rq->cpu, old_rd->online)) 5330 set_rq_offline(rq); 5331 5332 cpumask_clear_cpu(rq->cpu, old_rd->span); 5333 5334 /* 5335 * If we dont want to free the old_rd yet then 5336 * set old_rd to NULL to skip the freeing later 5337 * in this function: 5338 */ 5339 if (!atomic_dec_and_test(&old_rd->refcount)) 5340 old_rd = NULL; 5341 } 5342 5343 atomic_inc(&rd->refcount); 5344 rq->rd = rd; 5345 5346 cpumask_set_cpu(rq->cpu, rd->span); 5347 if (cpumask_test_cpu(rq->cpu, cpu_active_mask)) 5348 set_rq_online(rq); 5349 5350 raw_spin_unlock_irqrestore(&rq->lock, flags); 5351 5352 if (old_rd) 5353 call_rcu_sched(&old_rd->rcu, free_rootdomain); 5354} 5355 5356static int init_rootdomain(struct root_domain *rd) 5357{ 5358 memset(rd, 0, sizeof(*rd)); 5359 5360 if (!alloc_cpumask_var(&rd->span, GFP_KERNEL)) 5361 goto out; 5362 if (!alloc_cpumask_var(&rd->online, GFP_KERNEL)) 5363 goto free_span; 5364 if (!alloc_cpumask_var(&rd->dlo_mask, GFP_KERNEL)) 5365 goto free_online; 5366 if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL)) 5367 goto free_dlo_mask; 5368 5369 init_dl_bw(&rd->dl_bw); 5370 if (cpudl_init(&rd->cpudl) != 0) 5371 goto free_dlo_mask; 5372 5373 if (cpupri_init(&rd->cpupri) != 0) 5374 goto free_rto_mask; 5375 return 0; 5376 5377free_rto_mask: 5378 free_cpumask_var(rd->rto_mask); 5379free_dlo_mask: 5380 free_cpumask_var(rd->dlo_mask); 5381free_online: 5382 free_cpumask_var(rd->online); 5383free_span: 5384 free_cpumask_var(rd->span); 5385out: 5386 return -ENOMEM; 5387} 5388 5389/* 5390 * By default the system creates a single root-domain with all cpus as 5391 * members (mimicking the global state we have today). 5392 */ 5393struct root_domain def_root_domain; 5394 5395static void init_defrootdomain(void) 5396{ 5397 init_rootdomain(&def_root_domain); 5398 5399 atomic_set(&def_root_domain.refcount, 1); 5400} 5401 5402static struct root_domain *alloc_rootdomain(void) 5403{ 5404 struct root_domain *rd; 5405 5406 rd = kmalloc(sizeof(*rd), GFP_KERNEL); 5407 if (!rd) 5408 return NULL; 5409 5410 if (init_rootdomain(rd) != 0) { 5411 kfree(rd); 5412 return NULL; 5413 } 5414 5415 return rd; 5416} 5417 5418static void free_sched_groups(struct sched_group *sg, int free_sgp) 5419{ 5420 struct sched_group *tmp, *first; 5421 5422 if (!sg) 5423 return; 5424 5425 first = sg; 5426 do { 5427 tmp = sg->next; 5428 5429 if (free_sgp && atomic_dec_and_test(&sg->sgp->ref)) 5430 kfree(sg->sgp); 5431 5432 kfree(sg); 5433 sg = tmp; 5434 } while (sg != first); 5435} 5436 5437static void free_sched_domain(struct rcu_head *rcu) 5438{ 5439 struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu); 5440 5441 /* 5442 * If its an overlapping domain it has private groups, iterate and 5443 * nuke them all. 5444 */ 5445 if (sd->flags & SD_OVERLAP) { 5446 free_sched_groups(sd->groups, 1); 5447 } else if (atomic_dec_and_test(&sd->groups->ref)) { 5448 kfree(sd->groups->sgp); 5449 kfree(sd->groups); 5450 } 5451 kfree(sd); 5452} 5453 5454static void destroy_sched_domain(struct sched_domain *sd, int cpu) 5455{ 5456 call_rcu(&sd->rcu, free_sched_domain); 5457} 5458 5459static void destroy_sched_domains(struct sched_domain *sd, int cpu) 5460{ 5461 for (; sd; sd = sd->parent) 5462 destroy_sched_domain(sd, cpu); 5463} 5464 5465/* 5466 * Keep a special pointer to the highest sched_domain that has 5467 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this 5468 * allows us to avoid some pointer chasing select_idle_sibling(). 5469 * 5470 * Also keep a unique ID per domain (we use the first cpu number in 5471 * the cpumask of the domain), this allows us to quickly tell if 5472 * two cpus are in the same cache domain, see cpus_share_cache(). 5473 */ 5474DEFINE_PER_CPU(struct sched_domain *, sd_llc); 5475DEFINE_PER_CPU(int, sd_llc_size); 5476DEFINE_PER_CPU(int, sd_llc_id); 5477DEFINE_PER_CPU(struct sched_domain *, sd_numa); 5478DEFINE_PER_CPU(struct sched_domain *, sd_busy); 5479DEFINE_PER_CPU(struct sched_domain *, sd_asym); 5480 5481static void update_top_cache_domain(int cpu) 5482{ 5483 struct sched_domain *sd; 5484 struct sched_domain *busy_sd = NULL; 5485 int id = cpu; 5486 int size = 1; 5487 5488 sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES); 5489 if (sd) { 5490 id = cpumask_first(sched_domain_span(sd)); 5491 size = cpumask_weight(sched_domain_span(sd)); 5492 busy_sd = sd->parent; /* sd_busy */ 5493 } 5494 rcu_assign_pointer(per_cpu(sd_busy, cpu), busy_sd); 5495 5496 rcu_assign_pointer(per_cpu(sd_llc, cpu), sd); 5497 per_cpu(sd_llc_size, cpu) = size; 5498 per_cpu(sd_llc_id, cpu) = id; 5499 5500 sd = lowest_flag_domain(cpu, SD_NUMA); 5501 rcu_assign_pointer(per_cpu(sd_numa, cpu), sd); 5502 5503 sd = highest_flag_domain(cpu, SD_ASYM_PACKING); 5504 rcu_assign_pointer(per_cpu(sd_asym, cpu), sd); 5505} 5506 5507/* 5508 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must 5509 * hold the hotplug lock. 5510 */ 5511static void 5512cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) 5513{ 5514 struct rq *rq = cpu_rq(cpu); 5515 struct sched_domain *tmp; 5516 5517 /* Remove the sched domains which do not contribute to scheduling. */ 5518 for (tmp = sd; tmp; ) { 5519 struct sched_domain *parent = tmp->parent; 5520 if (!parent) 5521 break; 5522 5523 if (sd_parent_degenerate(tmp, parent)) { 5524 tmp->parent = parent->parent; 5525 if (parent->parent) 5526 parent->parent->child = tmp; 5527 /* 5528 * Transfer SD_PREFER_SIBLING down in case of a 5529 * degenerate parent; the spans match for this 5530 * so the property transfers. 5531 */ 5532 if (parent->flags & SD_PREFER_SIBLING) 5533 tmp->flags |= SD_PREFER_SIBLING; 5534 destroy_sched_domain(parent, cpu); 5535 } else 5536 tmp = tmp->parent; 5537 } 5538 5539 if (sd && sd_degenerate(sd)) { 5540 tmp = sd; 5541 sd = sd->parent; 5542 destroy_sched_domain(tmp, cpu); 5543 if (sd) 5544 sd->child = NULL; 5545 } 5546 5547 sched_domain_debug(sd, cpu); 5548 5549 rq_attach_root(rq, rd); 5550 tmp = rq->sd; 5551 rcu_assign_pointer(rq->sd, sd); 5552 destroy_sched_domains(tmp, cpu); 5553 5554 update_top_cache_domain(cpu); 5555} 5556 5557/* cpus with isolated domains */ 5558static cpumask_var_t cpu_isolated_map; 5559 5560/* Setup the mask of cpus configured for isolated domains */ 5561static int __init isolated_cpu_setup(char *str) 5562{ 5563 alloc_bootmem_cpumask_var(&cpu_isolated_map); 5564 cpulist_parse(str, cpu_isolated_map); 5565 return 1; 5566} 5567 5568__setup("isolcpus=", isolated_cpu_setup); 5569 5570static const struct cpumask *cpu_cpu_mask(int cpu) 5571{ 5572 return cpumask_of_node(cpu_to_node(cpu)); 5573} 5574 5575struct sd_data { 5576 struct sched_domain **__percpu sd; 5577 struct sched_group **__percpu sg; 5578 struct sched_group_power **__percpu sgp; 5579}; 5580 5581struct s_data { 5582 struct sched_domain ** __percpu sd; 5583 struct root_domain *rd; 5584}; 5585 5586enum s_alloc { 5587 sa_rootdomain, 5588 sa_sd, 5589 sa_sd_storage, 5590 sa_none, 5591}; 5592 5593struct sched_domain_topology_level; 5594 5595typedef struct sched_domain *(*sched_domain_init_f)(struct sched_domain_topology_level *tl, int cpu); 5596typedef const struct cpumask *(*sched_domain_mask_f)(int cpu); 5597 5598#define SDTL_OVERLAP 0x01 5599 5600struct sched_domain_topology_level { 5601 sched_domain_init_f init; 5602 sched_domain_mask_f mask; 5603 int flags; 5604 int numa_level; 5605 struct sd_data data; 5606}; 5607 5608/* 5609 * Build an iteration mask that can exclude certain CPUs from the upwards 5610 * domain traversal. 5611 * 5612 * Asymmetric node setups can result in situations where the domain tree is of 5613 * unequal depth, make sure to skip domains that already cover the entire 5614 * range. 5615 * 5616 * In that case build_sched_domains() will have terminated the iteration early 5617 * and our sibling sd spans will be empty. Domains should always include the 5618 * cpu they're built on, so check that. 5619 * 5620 */ 5621static void build_group_mask(struct sched_domain *sd, struct sched_group *sg) 5622{ 5623 const struct cpumask *span = sched_domain_span(sd); 5624 struct sd_data *sdd = sd->private; 5625 struct sched_domain *sibling; 5626 int i; 5627 5628 for_each_cpu(i, span) { 5629 sibling = *per_cpu_ptr(sdd->sd, i); 5630 if (!cpumask_test_cpu(i, sched_domain_span(sibling))) 5631 continue; 5632 5633 cpumask_set_cpu(i, sched_group_mask(sg)); 5634 } 5635} 5636 5637/* 5638 * Return the canonical balance cpu for this group, this is the first cpu 5639 * of this group that's also in the iteration mask. 5640 */ 5641int group_balance_cpu(struct sched_group *sg) 5642{ 5643 return cpumask_first_and(sched_group_cpus(sg), sched_group_mask(sg)); 5644} 5645 5646static int 5647build_overlap_sched_groups(struct sched_domain *sd, int cpu) 5648{ 5649 struct sched_group *first = NULL, *last = NULL, *groups = NULL, *sg; 5650 const struct cpumask *span = sched_domain_span(sd); 5651 struct cpumask *covered = sched_domains_tmpmask; 5652 struct sd_data *sdd = sd->private; 5653 struct sched_domain *child; 5654 int i; 5655 5656 cpumask_clear(covered); 5657 5658 for_each_cpu(i, span) { 5659 struct cpumask *sg_span; 5660 5661 if (cpumask_test_cpu(i, covered)) 5662 continue; 5663 5664 child = *per_cpu_ptr(sdd->sd, i); 5665 5666 /* See the comment near build_group_mask(). */ 5667 if (!cpumask_test_cpu(i, sched_domain_span(child))) 5668 continue; 5669 5670 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), 5671 GFP_KERNEL, cpu_to_node(cpu)); 5672 5673 if (!sg) 5674 goto fail; 5675 5676 sg_span = sched_group_cpus(sg); 5677 if (child->child) { 5678 child = child->child; 5679 cpumask_copy(sg_span, sched_domain_span(child)); 5680 } else 5681 cpumask_set_cpu(i, sg_span); 5682 5683 cpumask_or(covered, covered, sg_span); 5684 5685 sg->sgp = *per_cpu_ptr(sdd->sgp, i); 5686 if (atomic_inc_return(&sg->sgp->ref) == 1) 5687 build_group_mask(sd, sg); 5688 5689 /* 5690 * Initialize sgp->power such that even if we mess up the 5691 * domains and no possible iteration will get us here, we won't 5692 * die on a /0 trap. 5693 */ 5694 sg->sgp->power = SCHED_POWER_SCALE * cpumask_weight(sg_span); 5695 sg->sgp->power_orig = sg->sgp->power; 5696 5697 /* 5698 * Make sure the first group of this domain contains the 5699 * canonical balance cpu. Otherwise the sched_domain iteration 5700 * breaks. See update_sg_lb_stats(). 5701 */ 5702 if ((!groups && cpumask_test_cpu(cpu, sg_span)) || 5703 group_balance_cpu(sg) == cpu) 5704 groups = sg; 5705 5706 if (!first) 5707 first = sg; 5708 if (last) 5709 last->next = sg; 5710 last = sg; 5711 last->next = first; 5712 } 5713 sd->groups = groups; 5714 5715 return 0; 5716 5717fail: 5718 free_sched_groups(first, 0); 5719 5720 return -ENOMEM; 5721} 5722 5723static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg) 5724{ 5725 struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu); 5726 struct sched_domain *child = sd->child; 5727 5728 if (child) 5729 cpu = cpumask_first(sched_domain_span(child)); 5730 5731 if (sg) { 5732 *sg = *per_cpu_ptr(sdd->sg, cpu); 5733 (*sg)->sgp = *per_cpu_ptr(sdd->sgp, cpu); 5734 atomic_set(&(*sg)->sgp->ref, 1); /* for claim_allocations */ 5735 } 5736 5737 return cpu; 5738} 5739 5740/* 5741 * build_sched_groups will build a circular linked list of the groups 5742 * covered by the given span, and will set each group's ->cpumask correctly, 5743 * and ->cpu_power to 0. 5744 * 5745 * Assumes the sched_domain tree is fully constructed 5746 */ 5747static int 5748build_sched_groups(struct sched_domain *sd, int cpu) 5749{ 5750 struct sched_group *first = NULL, *last = NULL; 5751 struct sd_data *sdd = sd->private; 5752 const struct cpumask *span = sched_domain_span(sd); 5753 struct cpumask *covered; 5754 int i; 5755 5756 get_group(cpu, sdd, &sd->groups); 5757 atomic_inc(&sd->groups->ref); 5758 5759 if (cpu != cpumask_first(span)) 5760 return 0; 5761 5762 lockdep_assert_held(&sched_domains_mutex); 5763 covered = sched_domains_tmpmask; 5764 5765 cpumask_clear(covered); 5766 5767 for_each_cpu(i, span) { 5768 struct sched_group *sg; 5769 int group, j; 5770 5771 if (cpumask_test_cpu(i, covered)) 5772 continue; 5773 5774 group = get_group(i, sdd, &sg); 5775 cpumask_clear(sched_group_cpus(sg)); 5776 sg->sgp->power = 0; 5777 cpumask_setall(sched_group_mask(sg)); 5778 5779 for_each_cpu(j, span) { 5780 if (get_group(j, sdd, NULL) != group) 5781 continue; 5782 5783 cpumask_set_cpu(j, covered); 5784 cpumask_set_cpu(j, sched_group_cpus(sg)); 5785 } 5786 5787 if (!first) 5788 first = sg; 5789 if (last) 5790 last->next = sg; 5791 last = sg; 5792 } 5793 last->next = first; 5794 5795 return 0; 5796} 5797 5798/* 5799 * Initialize sched groups cpu_power. 5800 * 5801 * cpu_power indicates the capacity of sched group, which is used while 5802 * distributing the load between different sched groups in a sched domain. 5803 * Typically cpu_power for all the groups in a sched domain will be same unless 5804 * there are asymmetries in the topology. If there are asymmetries, group 5805 * having more cpu_power will pickup more load compared to the group having 5806 * less cpu_power. 5807 */ 5808static void init_sched_groups_power(int cpu, struct sched_domain *sd) 5809{ 5810 struct sched_group *sg = sd->groups; 5811 5812 WARN_ON(!sg); 5813 5814 do { 5815 sg->group_weight = cpumask_weight(sched_group_cpus(sg)); 5816 sg = sg->next; 5817 } while (sg != sd->groups); 5818 5819 if (cpu != group_balance_cpu(sg)) 5820 return; 5821 5822 update_group_power(sd, cpu); 5823 atomic_set(&sg->sgp->nr_busy_cpus, sg->group_weight); 5824} 5825 5826int __weak arch_sd_sibling_asym_packing(void) 5827{ 5828 return 0*SD_ASYM_PACKING; 5829} 5830 5831/* 5832 * Initializers for schedule domains 5833 * Non-inlined to reduce accumulated stack pressure in build_sched_domains() 5834 */ 5835 5836#ifdef CONFIG_SCHED_DEBUG 5837# define SD_INIT_NAME(sd, type) sd->name = #type 5838#else 5839# define SD_INIT_NAME(sd, type) do { } while (0) 5840#endif 5841 5842#define SD_INIT_FUNC(type) \ 5843static noinline struct sched_domain * \ 5844sd_init_##type(struct sched_domain_topology_level *tl, int cpu) \ 5845{ \ 5846 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); \ 5847 *sd = SD_##type##_INIT; \ 5848 SD_INIT_NAME(sd, type); \ 5849 sd->private = &tl->data; \ 5850 return sd; \ 5851} 5852 5853SD_INIT_FUNC(CPU) 5854#ifdef CONFIG_SCHED_SMT 5855 SD_INIT_FUNC(SIBLING) 5856#endif 5857#ifdef CONFIG_SCHED_MC 5858 SD_INIT_FUNC(MC) 5859#endif 5860#ifdef CONFIG_SCHED_BOOK 5861 SD_INIT_FUNC(BOOK) 5862#endif 5863 5864static int default_relax_domain_level = -1; 5865int sched_domain_level_max; 5866 5867static int __init setup_relax_domain_level(char *str) 5868{ 5869 if (kstrtoint(str, 0, &default_relax_domain_level)) 5870 pr_warn("Unable to set relax_domain_level\n"); 5871 5872 return 1; 5873} 5874__setup("relax_domain_level=", setup_relax_domain_level); 5875 5876static void set_domain_attribute(struct sched_domain *sd, 5877 struct sched_domain_attr *attr) 5878{ 5879 int request; 5880 5881 if (!attr || attr->relax_domain_level < 0) { 5882 if (default_relax_domain_level < 0) 5883 return; 5884 else 5885 request = default_relax_domain_level; 5886 } else 5887 request = attr->relax_domain_level; 5888 if (request < sd->level) { 5889 /* turn off idle balance on this domain */ 5890 sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); 5891 } else { 5892 /* turn on idle balance on this domain */ 5893 sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); 5894 } 5895} 5896 5897static void __sdt_free(const struct cpumask *cpu_map); 5898static int __sdt_alloc(const struct cpumask *cpu_map); 5899 5900static void __free_domain_allocs(struct s_data *d, enum s_alloc what, 5901 const struct cpumask *cpu_map) 5902{ 5903 switch (what) { 5904 case sa_rootdomain: 5905 if (!atomic_read(&d->rd->refcount)) 5906 free_rootdomain(&d->rd->rcu); /* fall through */ 5907 case sa_sd: 5908 free_percpu(d->sd); /* fall through */ 5909 case sa_sd_storage: 5910 __sdt_free(cpu_map); /* fall through */ 5911 case sa_none: 5912 break; 5913 } 5914} 5915 5916static enum s_alloc __visit_domain_allocation_hell(struct s_data *d, 5917 const struct cpumask *cpu_map) 5918{ 5919 memset(d, 0, sizeof(*d)); 5920 5921 if (__sdt_alloc(cpu_map)) 5922 return sa_sd_storage; 5923 d->sd = alloc_percpu(struct sched_domain *); 5924 if (!d->sd) 5925 return sa_sd_storage; 5926 d->rd = alloc_rootdomain(); 5927 if (!d->rd) 5928 return sa_sd; 5929 return sa_rootdomain; 5930} 5931 5932/* 5933 * NULL the sd_data elements we've used to build the sched_domain and 5934 * sched_group structure so that the subsequent __free_domain_allocs() 5935 * will not free the data we're using. 5936 */ 5937static void claim_allocations(int cpu, struct sched_domain *sd) 5938{ 5939 struct sd_data *sdd = sd->private; 5940 5941 WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd); 5942 *per_cpu_ptr(sdd->sd, cpu) = NULL; 5943 5944 if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref)) 5945 *per_cpu_ptr(sdd->sg, cpu) = NULL; 5946 5947 if (atomic_read(&(*per_cpu_ptr(sdd->sgp, cpu))->ref)) 5948 *per_cpu_ptr(sdd->sgp, cpu) = NULL; 5949} 5950 5951#ifdef CONFIG_SCHED_SMT 5952static const struct cpumask *cpu_smt_mask(int cpu) 5953{ 5954 return topology_thread_cpumask(cpu); 5955} 5956#endif 5957 5958/* 5959 * Topology list, bottom-up. 5960 */ 5961static struct sched_domain_topology_level default_topology[] = { 5962#ifdef CONFIG_SCHED_SMT 5963 { sd_init_SIBLING, cpu_smt_mask, }, 5964#endif 5965#ifdef CONFIG_SCHED_MC 5966 { sd_init_MC, cpu_coregroup_mask, }, 5967#endif 5968#ifdef CONFIG_SCHED_BOOK 5969 { sd_init_BOOK, cpu_book_mask, }, 5970#endif 5971 { sd_init_CPU, cpu_cpu_mask, }, 5972 { NULL, }, 5973}; 5974 5975static struct sched_domain_topology_level *sched_domain_topology = default_topology; 5976 5977#define for_each_sd_topology(tl) \ 5978 for (tl = sched_domain_topology; tl->init; tl++) 5979 5980#ifdef CONFIG_NUMA 5981 5982static int sched_domains_numa_levels; 5983static int *sched_domains_numa_distance; 5984static struct cpumask ***sched_domains_numa_masks; 5985static int sched_domains_curr_level; 5986 5987static inline int sd_local_flags(int level) 5988{ 5989 if (sched_domains_numa_distance[level] > RECLAIM_DISTANCE) 5990 return 0; 5991 5992 return SD_BALANCE_EXEC | SD_BALANCE_FORK | SD_WAKE_AFFINE; 5993} 5994 5995static struct sched_domain * 5996sd_numa_init(struct sched_domain_topology_level *tl, int cpu) 5997{ 5998 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); 5999 int level = tl->numa_level; 6000 int sd_weight = cpumask_weight( 6001 sched_domains_numa_masks[level][cpu_to_node(cpu)]); 6002 6003 *sd = (struct sched_domain){ 6004 .min_interval = sd_weight, 6005 .max_interval = 2*sd_weight, 6006 .busy_factor = 32, 6007 .imbalance_pct = 125, 6008 .cache_nice_tries = 2, 6009 .busy_idx = 3, 6010 .idle_idx = 2, 6011 .newidle_idx = 0, 6012 .wake_idx = 0, 6013 .forkexec_idx = 0, 6014 6015 .flags = 1*SD_LOAD_BALANCE 6016 | 1*SD_BALANCE_NEWIDLE 6017 | 0*SD_BALANCE_EXEC 6018 | 0*SD_BALANCE_FORK 6019 | 0*SD_BALANCE_WAKE 6020 | 0*SD_WAKE_AFFINE 6021 | 0*SD_SHARE_CPUPOWER 6022 | 0*SD_SHARE_PKG_RESOURCES 6023 | 1*SD_SERIALIZE 6024 | 0*SD_PREFER_SIBLING 6025 | 1*SD_NUMA 6026 | sd_local_flags(level) 6027 , 6028 .last_balance = jiffies, 6029 .balance_interval = sd_weight, 6030 .max_newidle_lb_cost = 0, 6031 .next_decay_max_lb_cost = jiffies, 6032 }; 6033 SD_INIT_NAME(sd, NUMA); 6034 sd->private = &tl->data; 6035 6036 /* 6037 * Ugly hack to pass state to sd_numa_mask()... 6038 */ 6039 sched_domains_curr_level = tl->numa_level; 6040 6041 return sd; 6042} 6043 6044static const struct cpumask *sd_numa_mask(int cpu) 6045{ 6046 return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)]; 6047} 6048 6049static void sched_numa_warn(const char *str) 6050{ 6051 static int done = false; 6052 int i,j; 6053 6054 if (done) 6055 return; 6056 6057 done = true; 6058 6059 printk(KERN_WARNING "ERROR: %s\n\n", str); 6060 6061 for (i = 0; i < nr_node_ids; i++) { 6062 printk(KERN_WARNING " "); 6063 for (j = 0; j < nr_node_ids; j++) 6064 printk(KERN_CONT "%02d ", node_distance(i,j)); 6065 printk(KERN_CONT "\n"); 6066 } 6067 printk(KERN_WARNING "\n"); 6068} 6069 6070static bool find_numa_distance(int distance) 6071{ 6072 int i; 6073 6074 if (distance == node_distance(0, 0)) 6075 return true; 6076 6077 for (i = 0; i < sched_domains_numa_levels; i++) { 6078 if (sched_domains_numa_distance[i] == distance) 6079 return true; 6080 } 6081 6082 return false; 6083} 6084 6085static void sched_init_numa(void) 6086{ 6087 int next_distance, curr_distance = node_distance(0, 0); 6088 struct sched_domain_topology_level *tl; 6089 int level = 0; 6090 int i, j, k; 6091 6092 sched_domains_numa_distance = kzalloc(sizeof(int) * nr_node_ids, GFP_KERNEL); 6093 if (!sched_domains_numa_distance) 6094 return; 6095 6096 /* 6097 * O(nr_nodes^2) deduplicating selection sort -- in order to find the 6098 * unique distances in the node_distance() table. 6099 * 6100 * Assumes node_distance(0,j) includes all distances in 6101 * node_distance(i,j) in order to avoid cubic time. 6102 */ 6103 next_distance = curr_distance; 6104 for (i = 0; i < nr_node_ids; i++) { 6105 for (j = 0; j < nr_node_ids; j++) { 6106 for (k = 0; k < nr_node_ids; k++) { 6107 int distance = node_distance(i, k); 6108 6109 if (distance > curr_distance && 6110 (distance < next_distance || 6111 next_distance == curr_distance)) 6112 next_distance = distance; 6113 6114 /* 6115 * While not a strong assumption it would be nice to know 6116 * about cases where if node A is connected to B, B is not 6117 * equally connected to A. 6118 */ 6119 if (sched_debug() && node_distance(k, i) != distance) 6120 sched_numa_warn("Node-distance not symmetric"); 6121 6122 if (sched_debug() && i && !find_numa_distance(distance)) 6123 sched_numa_warn("Node-0 not representative"); 6124 } 6125 if (next_distance != curr_distance) { 6126 sched_domains_numa_distance[level++] = next_distance; 6127 sched_domains_numa_levels = level; 6128 curr_distance = next_distance; 6129 } else break; 6130 } 6131 6132 /* 6133 * In case of sched_debug() we verify the above assumption. 6134 */ 6135 if (!sched_debug()) 6136 break; 6137 } 6138 /* 6139 * 'level' contains the number of unique distances, excluding the 6140 * identity distance node_distance(i,i). 6141 * 6142 * The sched_domains_numa_distance[] array includes the actual distance 6143 * numbers. 6144 */ 6145 6146 /* 6147 * Here, we should temporarily reset sched_domains_numa_levels to 0. 6148 * If it fails to allocate memory for array sched_domains_numa_masks[][], 6149 * the array will contain less then 'level' members. This could be 6150 * dangerous when we use it to iterate array sched_domains_numa_masks[][] 6151 * in other functions. 6152 * 6153 * We reset it to 'level' at the end of this function. 6154 */ 6155 sched_domains_numa_levels = 0; 6156 6157 sched_domains_numa_masks = kzalloc(sizeof(void *) * level, GFP_KERNEL); 6158 if (!sched_domains_numa_masks) 6159 return; 6160 6161 /* 6162 * Now for each level, construct a mask per node which contains all 6163 * cpus of nodes that are that many hops away from us. 6164 */ 6165 for (i = 0; i < level; i++) { 6166 sched_domains_numa_masks[i] = 6167 kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL); 6168 if (!sched_domains_numa_masks[i]) 6169 return; 6170 6171 for (j = 0; j < nr_node_ids; j++) { 6172 struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL); 6173 if (!mask) 6174 return; 6175 6176 sched_domains_numa_masks[i][j] = mask; 6177 6178 for (k = 0; k < nr_node_ids; k++) { 6179 if (node_distance(j, k) > sched_domains_numa_distance[i]) 6180 continue; 6181 6182 cpumask_or(mask, mask, cpumask_of_node(k)); 6183 } 6184 } 6185 } 6186 6187 tl = kzalloc((ARRAY_SIZE(default_topology) + level) * 6188 sizeof(struct sched_domain_topology_level), GFP_KERNEL); 6189 if (!tl) 6190 return; 6191 6192 /* 6193 * Copy the default topology bits.. 6194 */ 6195 for (i = 0; default_topology[i].init; i++) 6196 tl[i] = default_topology[i]; 6197 6198 /* 6199 * .. and append 'j' levels of NUMA goodness. 6200 */ 6201 for (j = 0; j < level; i++, j++) { 6202 tl[i] = (struct sched_domain_topology_level){ 6203 .init = sd_numa_init, 6204 .mask = sd_numa_mask, 6205 .flags = SDTL_OVERLAP, 6206 .numa_level = j, 6207 }; 6208 } 6209 6210 sched_domain_topology = tl; 6211 6212 sched_domains_numa_levels = level; 6213} 6214 6215static void sched_domains_numa_masks_set(int cpu) 6216{ 6217 int i, j; 6218 int node = cpu_to_node(cpu); 6219 6220 for (i = 0; i < sched_domains_numa_levels; i++) { 6221 for (j = 0; j < nr_node_ids; j++) { 6222 if (node_distance(j, node) <= sched_domains_numa_distance[i]) 6223 cpumask_set_cpu(cpu, sched_domains_numa_masks[i][j]); 6224 } 6225 } 6226} 6227 6228static void sched_domains_numa_masks_clear(int cpu) 6229{ 6230 int i, j; 6231 for (i = 0; i < sched_domains_numa_levels; i++) { 6232 for (j = 0; j < nr_node_ids; j++) 6233 cpumask_clear_cpu(cpu, sched_domains_numa_masks[i][j]); 6234 } 6235} 6236 6237/* 6238 * Update sched_domains_numa_masks[level][node] array when new cpus 6239 * are onlined. 6240 */ 6241static int sched_domains_numa_masks_update(struct notifier_block *nfb, 6242 unsigned long action, 6243 void *hcpu) 6244{ 6245 int cpu = (long)hcpu; 6246 6247 switch (action & ~CPU_TASKS_FROZEN) { 6248 case CPU_ONLINE: 6249 sched_domains_numa_masks_set(cpu); 6250 break; 6251 6252 case CPU_DEAD: 6253 sched_domains_numa_masks_clear(cpu); 6254 break; 6255 6256 default: 6257 return NOTIFY_DONE; 6258 } 6259 6260 return NOTIFY_OK; 6261} 6262#else 6263static inline void sched_init_numa(void) 6264{ 6265} 6266 6267static int sched_domains_numa_masks_update(struct notifier_block *nfb, 6268 unsigned long action, 6269 void *hcpu) 6270{ 6271 return 0; 6272} 6273#endif /* CONFIG_NUMA */ 6274 6275static int __sdt_alloc(const struct cpumask *cpu_map) 6276{ 6277 struct sched_domain_topology_level *tl; 6278 int j; 6279 6280 for_each_sd_topology(tl) { 6281 struct sd_data *sdd = &tl->data; 6282 6283 sdd->sd = alloc_percpu(struct sched_domain *); 6284 if (!sdd->sd) 6285 return -ENOMEM; 6286 6287 sdd->sg = alloc_percpu(struct sched_group *); 6288 if (!sdd->sg) 6289 return -ENOMEM; 6290 6291 sdd->sgp = alloc_percpu(struct sched_group_power *); 6292 if (!sdd->sgp) 6293 return -ENOMEM; 6294 6295 for_each_cpu(j, cpu_map) { 6296 struct sched_domain *sd; 6297 struct sched_group *sg; 6298 struct sched_group_power *sgp; 6299 6300 sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(), 6301 GFP_KERNEL, cpu_to_node(j)); 6302 if (!sd) 6303 return -ENOMEM; 6304 6305 *per_cpu_ptr(sdd->sd, j) = sd; 6306 6307 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), 6308 GFP_KERNEL, cpu_to_node(j)); 6309 if (!sg) 6310 return -ENOMEM; 6311 6312 sg->next = sg; 6313 6314 *per_cpu_ptr(sdd->sg, j) = sg; 6315 6316 sgp = kzalloc_node(sizeof(struct sched_group_power) + cpumask_size(), 6317 GFP_KERNEL, cpu_to_node(j)); 6318 if (!sgp) 6319 return -ENOMEM; 6320 6321 *per_cpu_ptr(sdd->sgp, j) = sgp; 6322 } 6323 } 6324 6325 return 0; 6326} 6327 6328static void __sdt_free(const struct cpumask *cpu_map) 6329{ 6330 struct sched_domain_topology_level *tl; 6331 int j; 6332 6333 for_each_sd_topology(tl) { 6334 struct sd_data *sdd = &tl->data; 6335 6336 for_each_cpu(j, cpu_map) { 6337 struct sched_domain *sd; 6338 6339 if (sdd->sd) { 6340 sd = *per_cpu_ptr(sdd->sd, j); 6341 if (sd && (sd->flags & SD_OVERLAP)) 6342 free_sched_groups(sd->groups, 0); 6343 kfree(*per_cpu_ptr(sdd->sd, j)); 6344 } 6345 6346 if (sdd->sg) 6347 kfree(*per_cpu_ptr(sdd->sg, j)); 6348 if (sdd->sgp) 6349 kfree(*per_cpu_ptr(sdd->sgp, j)); 6350 } 6351 free_percpu(sdd->sd); 6352 sdd->sd = NULL; 6353 free_percpu(sdd->sg); 6354 sdd->sg = NULL; 6355 free_percpu(sdd->sgp); 6356 sdd->sgp = NULL; 6357 } 6358} 6359 6360struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl, 6361 const struct cpumask *cpu_map, struct sched_domain_attr *attr, 6362 struct sched_domain *child, int cpu) 6363{ 6364 struct sched_domain *sd = tl->init(tl, cpu); 6365 if (!sd) 6366 return child; 6367 6368 cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu)); 6369 if (child) { 6370 sd->level = child->level + 1; 6371 sched_domain_level_max = max(sched_domain_level_max, sd->level); 6372 child->parent = sd; 6373 sd->child = child; 6374 } 6375 set_domain_attribute(sd, attr); 6376 6377 return sd; 6378} 6379 6380/* 6381 * Build sched domains for a given set of cpus and attach the sched domains 6382 * to the individual cpus 6383 */ 6384static int build_sched_domains(const struct cpumask *cpu_map, 6385 struct sched_domain_attr *attr) 6386{ 6387 enum s_alloc alloc_state; 6388 struct sched_domain *sd; 6389 struct s_data d; 6390 int i, ret = -ENOMEM; 6391 6392 alloc_state = __visit_domain_allocation_hell(&d, cpu_map); 6393 if (alloc_state != sa_rootdomain) 6394 goto error; 6395 6396 /* Set up domains for cpus specified by the cpu_map. */ 6397 for_each_cpu(i, cpu_map) { 6398 struct sched_domain_topology_level *tl; 6399 6400 sd = NULL; 6401 for_each_sd_topology(tl) { 6402 sd = build_sched_domain(tl, cpu_map, attr, sd, i); 6403 if (tl == sched_domain_topology) 6404 *per_cpu_ptr(d.sd, i) = sd; 6405 if (tl->flags & SDTL_OVERLAP || sched_feat(FORCE_SD_OVERLAP)) 6406 sd->flags |= SD_OVERLAP; 6407 if (cpumask_equal(cpu_map, sched_domain_span(sd))) 6408 break; 6409 } 6410 } 6411 6412 /* Build the groups for the domains */ 6413 for_each_cpu(i, cpu_map) { 6414 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { 6415 sd->span_weight = cpumask_weight(sched_domain_span(sd)); 6416 if (sd->flags & SD_OVERLAP) { 6417 if (build_overlap_sched_groups(sd, i)) 6418 goto error; 6419 } else { 6420 if (build_sched_groups(sd, i)) 6421 goto error; 6422 } 6423 } 6424 } 6425 6426 /* Calculate CPU power for physical packages and nodes */ 6427 for (i = nr_cpumask_bits-1; i >= 0; i--) { 6428 if (!cpumask_test_cpu(i, cpu_map)) 6429 continue; 6430 6431 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { 6432 claim_allocations(i, sd); 6433 init_sched_groups_power(i, sd); 6434 } 6435 } 6436 6437 /* Attach the domains */ 6438 rcu_read_lock(); 6439 for_each_cpu(i, cpu_map) { 6440 sd = *per_cpu_ptr(d.sd, i); 6441 cpu_attach_domain(sd, d.rd, i); 6442 } 6443 rcu_read_unlock(); 6444 6445 ret = 0; 6446error: 6447 __free_domain_allocs(&d, alloc_state, cpu_map); 6448 return ret; 6449} 6450 6451static cpumask_var_t *doms_cur; /* current sched domains */ 6452static int ndoms_cur; /* number of sched domains in 'doms_cur' */ 6453static struct sched_domain_attr *dattr_cur; 6454 /* attribues of custom domains in 'doms_cur' */ 6455 6456/* 6457 * Special case: If a kmalloc of a doms_cur partition (array of 6458 * cpumask) fails, then fallback to a single sched domain, 6459 * as determined by the single cpumask fallback_doms. 6460 */ 6461static cpumask_var_t fallback_doms; 6462 6463/* 6464 * arch_update_cpu_topology lets virtualized architectures update the 6465 * cpu core maps. It is supposed to return 1 if the topology changed 6466 * or 0 if it stayed the same. 6467 */ 6468int __weak arch_update_cpu_topology(void) 6469{ 6470 return 0; 6471} 6472 6473cpumask_var_t *alloc_sched_domains(unsigned int ndoms) 6474{ 6475 int i; 6476 cpumask_var_t *doms; 6477 6478 doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL); 6479 if (!doms) 6480 return NULL; 6481 for (i = 0; i < ndoms; i++) { 6482 if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) { 6483 free_sched_domains(doms, i); 6484 return NULL; 6485 } 6486 } 6487 return doms; 6488} 6489 6490void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms) 6491{ 6492 unsigned int i; 6493 for (i = 0; i < ndoms; i++) 6494 free_cpumask_var(doms[i]); 6495 kfree(doms); 6496} 6497 6498/* 6499 * Set up scheduler domains and groups. Callers must hold the hotplug lock. 6500 * For now this just excludes isolated cpus, but could be used to 6501 * exclude other special cases in the future. 6502 */ 6503static int init_sched_domains(const struct cpumask *cpu_map) 6504{ 6505 int err; 6506 6507 arch_update_cpu_topology(); 6508 ndoms_cur = 1; 6509 doms_cur = alloc_sched_domains(ndoms_cur); 6510 if (!doms_cur) 6511 doms_cur = &fallback_doms; 6512 cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map); 6513 err = build_sched_domains(doms_cur[0], NULL); 6514 register_sched_domain_sysctl(); 6515 6516 return err; 6517} 6518 6519/* 6520 * Detach sched domains from a group of cpus specified in cpu_map 6521 * These cpus will now be attached to the NULL domain 6522 */ 6523static void detach_destroy_domains(const struct cpumask *cpu_map) 6524{ 6525 int i; 6526 6527 rcu_read_lock(); 6528 for_each_cpu(i, cpu_map) 6529 cpu_attach_domain(NULL, &def_root_domain, i); 6530 rcu_read_unlock(); 6531} 6532 6533/* handle null as "default" */ 6534static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur, 6535 struct sched_domain_attr *new, int idx_new) 6536{ 6537 struct sched_domain_attr tmp; 6538 6539 /* fast path */ 6540 if (!new && !cur) 6541 return 1; 6542 6543 tmp = SD_ATTR_INIT; 6544 return !memcmp(cur ? (cur + idx_cur) : &tmp, 6545 new ? (new + idx_new) : &tmp, 6546 sizeof(struct sched_domain_attr)); 6547} 6548 6549/* 6550 * Partition sched domains as specified by the 'ndoms_new' 6551 * cpumasks in the array doms_new[] of cpumasks. This compares 6552 * doms_new[] to the current sched domain partitioning, doms_cur[]. 6553 * It destroys each deleted domain and builds each new domain. 6554 * 6555 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'. 6556 * The masks don't intersect (don't overlap.) We should setup one 6557 * sched domain for each mask. CPUs not in any of the cpumasks will 6558 * not be load balanced. If the same cpumask appears both in the 6559 * current 'doms_cur' domains and in the new 'doms_new', we can leave 6560 * it as it is. 6561 * 6562 * The passed in 'doms_new' should be allocated using 6563 * alloc_sched_domains. This routine takes ownership of it and will 6564 * free_sched_domains it when done with it. If the caller failed the 6565 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1, 6566 * and partition_sched_domains() will fallback to the single partition 6567 * 'fallback_doms', it also forces the domains to be rebuilt. 6568 * 6569 * If doms_new == NULL it will be replaced with cpu_online_mask. 6570 * ndoms_new == 0 is a special case for destroying existing domains, 6571 * and it will not create the default domain. 6572 * 6573 * Call with hotplug lock held 6574 */ 6575void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[], 6576 struct sched_domain_attr *dattr_new) 6577{ 6578 int i, j, n; 6579 int new_topology; 6580 6581 mutex_lock(&sched_domains_mutex); 6582 6583 /* always unregister in case we don't destroy any domains */ 6584 unregister_sched_domain_sysctl(); 6585 6586 /* Let architecture update cpu core mappings. */ 6587 new_topology = arch_update_cpu_topology(); 6588 6589 n = doms_new ? ndoms_new : 0; 6590 6591 /* Destroy deleted domains */ 6592 for (i = 0; i < ndoms_cur; i++) { 6593 for (j = 0; j < n && !new_topology; j++) { 6594 if (cpumask_equal(doms_cur[i], doms_new[j]) 6595 && dattrs_equal(dattr_cur, i, dattr_new, j)) 6596 goto match1; 6597 } 6598 /* no match - a current sched domain not in new doms_new[] */ 6599 detach_destroy_domains(doms_cur[i]); 6600match1: 6601 ; 6602 } 6603 6604 n = ndoms_cur; 6605 if (doms_new == NULL) { 6606 n = 0; 6607 doms_new = &fallback_doms; 6608 cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map); 6609 WARN_ON_ONCE(dattr_new); 6610 } 6611 6612 /* Build new domains */ 6613 for (i = 0; i < ndoms_new; i++) { 6614 for (j = 0; j < n && !new_topology; j++) { 6615 if (cpumask_equal(doms_new[i], doms_cur[j]) 6616 && dattrs_equal(dattr_new, i, dattr_cur, j)) 6617 goto match2; 6618 } 6619 /* no match - add a new doms_new */ 6620 build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL); 6621match2: 6622 ; 6623 } 6624 6625 /* Remember the new sched domains */ 6626 if (doms_cur != &fallback_doms) 6627 free_sched_domains(doms_cur, ndoms_cur); 6628 kfree(dattr_cur); /* kfree(NULL) is safe */ 6629 doms_cur = doms_new; 6630 dattr_cur = dattr_new; 6631 ndoms_cur = ndoms_new; 6632 6633 register_sched_domain_sysctl(); 6634 6635 mutex_unlock(&sched_domains_mutex); 6636} 6637 6638static int num_cpus_frozen; /* used to mark begin/end of suspend/resume */ 6639 6640/* 6641 * Update cpusets according to cpu_active mask. If cpusets are 6642 * disabled, cpuset_update_active_cpus() becomes a simple wrapper 6643 * around partition_sched_domains(). 6644 * 6645 * If we come here as part of a suspend/resume, don't touch cpusets because we 6646 * want to restore it back to its original state upon resume anyway. 6647 */ 6648static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action, 6649 void *hcpu) 6650{ 6651 switch (action) { 6652 case CPU_ONLINE_FROZEN: 6653 case CPU_DOWN_FAILED_FROZEN: 6654 6655 /* 6656 * num_cpus_frozen tracks how many CPUs are involved in suspend 6657 * resume sequence. As long as this is not the last online 6658 * operation in the resume sequence, just build a single sched 6659 * domain, ignoring cpusets. 6660 */ 6661 num_cpus_frozen--; 6662 if (likely(num_cpus_frozen)) { 6663 partition_sched_domains(1, NULL, NULL); 6664 break; 6665 } 6666 6667 /* 6668 * This is the last CPU online operation. So fall through and 6669 * restore the original sched domains by considering the 6670 * cpuset configurations. 6671 */ 6672 6673 case CPU_ONLINE: 6674 case CPU_DOWN_FAILED: 6675 cpuset_update_active_cpus(true); 6676 break; 6677 default: 6678 return NOTIFY_DONE; 6679 } 6680 return NOTIFY_OK; 6681} 6682 6683static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action, 6684 void *hcpu) 6685{ 6686 switch (action) { 6687 case CPU_DOWN_PREPARE: 6688 cpuset_update_active_cpus(false); 6689 break; 6690 case CPU_DOWN_PREPARE_FROZEN: 6691 num_cpus_frozen++; 6692 partition_sched_domains(1, NULL, NULL); 6693 break; 6694 default: 6695 return NOTIFY_DONE; 6696 } 6697 return NOTIFY_OK; 6698} 6699 6700void __init sched_init_smp(void) 6701{ 6702 cpumask_var_t non_isolated_cpus; 6703 6704 alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL); 6705 alloc_cpumask_var(&fallback_doms, GFP_KERNEL); 6706 6707 sched_init_numa(); 6708 6709 /* 6710 * There's no userspace yet to cause hotplug operations; hence all the 6711 * cpu masks are stable and all blatant races in the below code cannot 6712 * happen. 6713 */ 6714 mutex_lock(&sched_domains_mutex); 6715 init_sched_domains(cpu_active_mask); 6716 cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map); 6717 if (cpumask_empty(non_isolated_cpus)) 6718 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus); 6719 mutex_unlock(&sched_domains_mutex); 6720 6721 hotcpu_notifier(sched_domains_numa_masks_update, CPU_PRI_SCHED_ACTIVE); 6722 hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE); 6723 hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE); 6724 6725 init_hrtick(); 6726 6727 /* Move init over to a non-isolated CPU */ 6728 if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0) 6729 BUG(); 6730 sched_init_granularity(); 6731 free_cpumask_var(non_isolated_cpus); 6732 6733 init_sched_rt_class(); 6734 init_sched_dl_class(); 6735} 6736#else 6737void __init sched_init_smp(void) 6738{ 6739 sched_init_granularity(); 6740} 6741#endif /* CONFIG_SMP */ 6742 6743const_debug unsigned int sysctl_timer_migration = 1; 6744 6745int in_sched_functions(unsigned long addr) 6746{ 6747 return in_lock_functions(addr) || 6748 (addr >= (unsigned long)__sched_text_start 6749 && addr < (unsigned long)__sched_text_end); 6750} 6751 6752#ifdef CONFIG_CGROUP_SCHED 6753/* 6754 * Default task group. 6755 * Every task in system belongs to this group at bootup. 6756 */ 6757struct task_group root_task_group; 6758LIST_HEAD(task_groups); 6759#endif 6760 6761DECLARE_PER_CPU(cpumask_var_t, load_balance_mask); 6762 6763void __init sched_init(void) 6764{ 6765 int i, j; 6766 unsigned long alloc_size = 0, ptr; 6767 6768#ifdef CONFIG_FAIR_GROUP_SCHED 6769 alloc_size += 2 * nr_cpu_ids * sizeof(void **); 6770#endif 6771#ifdef CONFIG_RT_GROUP_SCHED 6772 alloc_size += 2 * nr_cpu_ids * sizeof(void **); 6773#endif 6774#ifdef CONFIG_CPUMASK_OFFSTACK 6775 alloc_size += num_possible_cpus() * cpumask_size(); 6776#endif 6777 if (alloc_size) { 6778 ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT); 6779 6780#ifdef CONFIG_FAIR_GROUP_SCHED 6781 root_task_group.se = (struct sched_entity **)ptr; 6782 ptr += nr_cpu_ids * sizeof(void **); 6783 6784 root_task_group.cfs_rq = (struct cfs_rq **)ptr; 6785 ptr += nr_cpu_ids * sizeof(void **); 6786 6787#endif /* CONFIG_FAIR_GROUP_SCHED */ 6788#ifdef CONFIG_RT_GROUP_SCHED 6789 root_task_group.rt_se = (struct sched_rt_entity **)ptr; 6790 ptr += nr_cpu_ids * sizeof(void **); 6791 6792 root_task_group.rt_rq = (struct rt_rq **)ptr; 6793 ptr += nr_cpu_ids * sizeof(void **); 6794 6795#endif /* CONFIG_RT_GROUP_SCHED */ 6796#ifdef CONFIG_CPUMASK_OFFSTACK 6797 for_each_possible_cpu(i) { 6798 per_cpu(load_balance_mask, i) = (void *)ptr; 6799 ptr += cpumask_size(); 6800 } 6801#endif /* CONFIG_CPUMASK_OFFSTACK */ 6802 } 6803 6804 init_rt_bandwidth(&def_rt_bandwidth, 6805 global_rt_period(), global_rt_runtime()); 6806 init_dl_bandwidth(&def_dl_bandwidth, 6807 global_rt_period(), global_rt_runtime()); 6808 6809#ifdef CONFIG_SMP 6810 init_defrootdomain(); 6811#endif 6812 6813#ifdef CONFIG_RT_GROUP_SCHED 6814 init_rt_bandwidth(&root_task_group.rt_bandwidth, 6815 global_rt_period(), global_rt_runtime()); 6816#endif /* CONFIG_RT_GROUP_SCHED */ 6817 6818#ifdef CONFIG_CGROUP_SCHED 6819 list_add(&root_task_group.list, &task_groups); 6820 INIT_LIST_HEAD(&root_task_group.children); 6821 INIT_LIST_HEAD(&root_task_group.siblings); 6822 autogroup_init(&init_task); 6823 6824#endif /* CONFIG_CGROUP_SCHED */ 6825 6826 for_each_possible_cpu(i) { 6827 struct rq *rq; 6828 6829 rq = cpu_rq(i); 6830 raw_spin_lock_init(&rq->lock); 6831 rq->nr_running = 0; 6832 rq->calc_load_active = 0; 6833 rq->calc_load_update = jiffies + LOAD_FREQ; 6834 init_cfs_rq(&rq->cfs); 6835 init_rt_rq(&rq->rt, rq); 6836 init_dl_rq(&rq->dl, rq); 6837#ifdef CONFIG_FAIR_GROUP_SCHED 6838 root_task_group.shares = ROOT_TASK_GROUP_LOAD; 6839 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list); 6840 /* 6841 * How much cpu bandwidth does root_task_group get? 6842 * 6843 * In case of task-groups formed thr' the cgroup filesystem, it 6844 * gets 100% of the cpu resources in the system. This overall 6845 * system cpu resource is divided among the tasks of 6846 * root_task_group and its child task-groups in a fair manner, 6847 * based on each entity's (task or task-group's) weight 6848 * (se->load.weight). 6849 * 6850 * In other words, if root_task_group has 10 tasks of weight 6851 * 1024) and two child groups A0 and A1 (of weight 1024 each), 6852 * then A0's share of the cpu resource is: 6853 * 6854 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33% 6855 * 6856 * We achieve this by letting root_task_group's tasks sit 6857 * directly in rq->cfs (i.e root_task_group->se[] = NULL). 6858 */ 6859 init_cfs_bandwidth(&root_task_group.cfs_bandwidth); 6860 init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL); 6861#endif /* CONFIG_FAIR_GROUP_SCHED */ 6862 6863 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime; 6864#ifdef CONFIG_RT_GROUP_SCHED 6865 init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL); 6866#endif 6867 6868 for (j = 0; j < CPU_LOAD_IDX_MAX; j++) 6869 rq->cpu_load[j] = 0; 6870 6871 rq->last_load_update_tick = jiffies; 6872 6873#ifdef CONFIG_SMP 6874 rq->sd = NULL; 6875 rq->rd = NULL; 6876 rq->cpu_power = SCHED_POWER_SCALE; 6877 rq->post_schedule = 0; 6878 rq->active_balance = 0; 6879 rq->next_balance = jiffies; 6880 rq->push_cpu = 0; 6881 rq->cpu = i; 6882 rq->online = 0; 6883 rq->idle_stamp = 0; 6884 rq->avg_idle = 2*sysctl_sched_migration_cost; 6885 rq->max_idle_balance_cost = sysctl_sched_migration_cost; 6886 6887 INIT_LIST_HEAD(&rq->cfs_tasks); 6888 6889 rq_attach_root(rq, &def_root_domain); 6890#ifdef CONFIG_NO_HZ_COMMON 6891 rq->nohz_flags = 0; 6892#endif 6893#ifdef CONFIG_NO_HZ_FULL 6894 rq->last_sched_tick = 0; 6895#endif 6896#endif 6897 init_rq_hrtick(rq); 6898 atomic_set(&rq->nr_iowait, 0); 6899 } 6900 6901 set_load_weight(&init_task); 6902 6903#ifdef CONFIG_PREEMPT_NOTIFIERS 6904 INIT_HLIST_HEAD(&init_task.preempt_notifiers); 6905#endif 6906 6907 /* 6908 * The boot idle thread does lazy MMU switching as well: 6909 */ 6910 atomic_inc(&init_mm.mm_count); 6911 enter_lazy_tlb(&init_mm, current); 6912 6913 /* 6914 * Make us the idle thread. Technically, schedule() should not be 6915 * called from this thread, however somewhere below it might be, 6916 * but because we are the idle thread, we just pick up running again 6917 * when this runqueue becomes "idle". 6918 */ 6919 init_idle(current, smp_processor_id()); 6920 6921 calc_load_update = jiffies + LOAD_FREQ; 6922 6923 /* 6924 * During early bootup we pretend to be a normal task: 6925 */ 6926 current->sched_class = &fair_sched_class; 6927 6928#ifdef CONFIG_SMP 6929 zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT); 6930 /* May be allocated at isolcpus cmdline parse time */ 6931 if (cpu_isolated_map == NULL) 6932 zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT); 6933 idle_thread_set_boot_cpu(); 6934#endif 6935 init_sched_fair_class(); 6936 6937 scheduler_running = 1; 6938} 6939 6940#ifdef CONFIG_DEBUG_ATOMIC_SLEEP 6941static inline int preempt_count_equals(int preempt_offset) 6942{ 6943 int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth(); 6944 6945 return (nested == preempt_offset); 6946} 6947 6948void __might_sleep(const char *file, int line, int preempt_offset) 6949{ 6950 static unsigned long prev_jiffy; /* ratelimiting */ 6951 6952 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */ 6953 if ((preempt_count_equals(preempt_offset) && !irqs_disabled() && 6954 !is_idle_task(current)) || 6955 system_state != SYSTEM_RUNNING || oops_in_progress) 6956 return; 6957 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) 6958 return; 6959 prev_jiffy = jiffies; 6960 6961 printk(KERN_ERR 6962 "BUG: sleeping function called from invalid context at %s:%d\n", 6963 file, line); 6964 printk(KERN_ERR 6965 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n", 6966 in_atomic(), irqs_disabled(), 6967 current->pid, current->comm); 6968 6969 debug_show_held_locks(current); 6970 if (irqs_disabled()) 6971 print_irqtrace_events(current); 6972#ifdef CONFIG_DEBUG_PREEMPT 6973 if (!preempt_count_equals(preempt_offset)) { 6974 pr_err("Preemption disabled at:"); 6975 print_ip_sym(current->preempt_disable_ip); 6976 pr_cont("\n"); 6977 } 6978#endif 6979 dump_stack(); 6980} 6981EXPORT_SYMBOL(__might_sleep); 6982#endif 6983 6984#ifdef CONFIG_MAGIC_SYSRQ 6985static void normalize_task(struct rq *rq, struct task_struct *p) 6986{ 6987 const struct sched_class *prev_class = p->sched_class; 6988 struct sched_attr attr = { 6989 .sched_policy = SCHED_NORMAL, 6990 }; 6991 int old_prio = p->prio; 6992 int on_rq; 6993 6994 on_rq = p->on_rq; 6995 if (on_rq) 6996 dequeue_task(rq, p, 0); 6997 __setscheduler(rq, p, &attr); 6998 if (on_rq) { 6999 enqueue_task(rq, p, 0); 7000 resched_task(rq->curr); 7001 } 7002 7003 check_class_changed(rq, p, prev_class, old_prio); 7004} 7005 7006void normalize_rt_tasks(void) 7007{ 7008 struct task_struct *g, *p; 7009 unsigned long flags; 7010 struct rq *rq; 7011 7012 read_lock_irqsave(&tasklist_lock, flags); 7013 do_each_thread(g, p) { 7014 /* 7015 * Only normalize user tasks: 7016 */ 7017 if (!p->mm) 7018 continue; 7019 7020 p->se.exec_start = 0; 7021#ifdef CONFIG_SCHEDSTATS 7022 p->se.statistics.wait_start = 0; 7023 p->se.statistics.sleep_start = 0; 7024 p->se.statistics.block_start = 0; 7025#endif 7026 7027 if (!dl_task(p) && !rt_task(p)) { 7028 /* 7029 * Renice negative nice level userspace 7030 * tasks back to 0: 7031 */ 7032 if (task_nice(p) < 0 && p->mm) 7033 set_user_nice(p, 0); 7034 continue; 7035 } 7036 7037 raw_spin_lock(&p->pi_lock); 7038 rq = __task_rq_lock(p); 7039 7040 normalize_task(rq, p); 7041 7042 __task_rq_unlock(rq); 7043 raw_spin_unlock(&p->pi_lock); 7044 } while_each_thread(g, p); 7045 7046 read_unlock_irqrestore(&tasklist_lock, flags); 7047} 7048 7049#endif /* CONFIG_MAGIC_SYSRQ */ 7050 7051#if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) 7052/* 7053 * These functions are only useful for the IA64 MCA handling, or kdb. 7054 * 7055 * They can only be called when the whole system has been 7056 * stopped - every CPU needs to be quiescent, and no scheduling 7057 * activity can take place. Using them for anything else would 7058 * be a serious bug, and as a result, they aren't even visible 7059 * under any other configuration. 7060 */ 7061 7062/** 7063 * curr_task - return the current task for a given cpu. 7064 * @cpu: the processor in question. 7065 * 7066 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! 7067 * 7068 * Return: The current task for @cpu. 7069 */ 7070struct task_struct *curr_task(int cpu) 7071{ 7072 return cpu_curr(cpu); 7073} 7074 7075#endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */ 7076 7077#ifdef CONFIG_IA64 7078/** 7079 * set_curr_task - set the current task for a given cpu. 7080 * @cpu: the processor in question. 7081 * @p: the task pointer to set. 7082 * 7083 * Description: This function must only be used when non-maskable interrupts 7084 * are serviced on a separate stack. It allows the architecture to switch the 7085 * notion of the current task on a cpu in a non-blocking manner. This function 7086 * must be called with all CPU's synchronized, and interrupts disabled, the 7087 * and caller must save the original value of the current task (see 7088 * curr_task() above) and restore that value before reenabling interrupts and 7089 * re-starting the system. 7090 * 7091 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! 7092 */ 7093void set_curr_task(int cpu, struct task_struct *p) 7094{ 7095 cpu_curr(cpu) = p; 7096} 7097 7098#endif 7099 7100#ifdef CONFIG_CGROUP_SCHED 7101/* task_group_lock serializes the addition/removal of task groups */ 7102static DEFINE_SPINLOCK(task_group_lock); 7103 7104static void free_sched_group(struct task_group *tg) 7105{ 7106 free_fair_sched_group(tg); 7107 free_rt_sched_group(tg); 7108 autogroup_free(tg); 7109 kfree(tg); 7110} 7111 7112/* allocate runqueue etc for a new task group */ 7113struct task_group *sched_create_group(struct task_group *parent) 7114{ 7115 struct task_group *tg; 7116 7117 tg = kzalloc(sizeof(*tg), GFP_KERNEL); 7118 if (!tg) 7119 return ERR_PTR(-ENOMEM); 7120 7121 if (!alloc_fair_sched_group(tg, parent)) 7122 goto err; 7123 7124 if (!alloc_rt_sched_group(tg, parent)) 7125 goto err; 7126 7127 return tg; 7128 7129err: 7130 free_sched_group(tg); 7131 return ERR_PTR(-ENOMEM); 7132} 7133 7134void sched_online_group(struct task_group *tg, struct task_group *parent) 7135{ 7136 unsigned long flags; 7137 7138 spin_lock_irqsave(&task_group_lock, flags); 7139 list_add_rcu(&tg->list, &task_groups); 7140 7141 WARN_ON(!parent); /* root should already exist */ 7142 7143 tg->parent = parent; 7144 INIT_LIST_HEAD(&tg->children); 7145 list_add_rcu(&tg->siblings, &parent->children); 7146 spin_unlock_irqrestore(&task_group_lock, flags); 7147} 7148 7149/* rcu callback to free various structures associated with a task group */ 7150static void free_sched_group_rcu(struct rcu_head *rhp) 7151{ 7152 /* now it should be safe to free those cfs_rqs */ 7153 free_sched_group(container_of(rhp, struct task_group, rcu)); 7154} 7155 7156/* Destroy runqueue etc associated with a task group */ 7157void sched_destroy_group(struct task_group *tg) 7158{ 7159 /* wait for possible concurrent references to cfs_rqs complete */ 7160 call_rcu(&tg->rcu, free_sched_group_rcu); 7161} 7162 7163void sched_offline_group(struct task_group *tg) 7164{ 7165 unsigned long flags; 7166 int i; 7167 7168 /* end participation in shares distribution */ 7169 for_each_possible_cpu(i) 7170 unregister_fair_sched_group(tg, i); 7171 7172 spin_lock_irqsave(&task_group_lock, flags); 7173 list_del_rcu(&tg->list); 7174 list_del_rcu(&tg->siblings); 7175 spin_unlock_irqrestore(&task_group_lock, flags); 7176} 7177 7178/* change task's runqueue when it moves between groups. 7179 * The caller of this function should have put the task in its new group 7180 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to 7181 * reflect its new group. 7182 */ 7183void sched_move_task(struct task_struct *tsk) 7184{ 7185 struct task_group *tg; 7186 int on_rq, running; 7187 unsigned long flags; 7188 struct rq *rq; 7189 7190 rq = task_rq_lock(tsk, &flags); 7191 7192 running = task_current(rq, tsk); 7193 on_rq = tsk->on_rq; 7194 7195 if (on_rq) 7196 dequeue_task(rq, tsk, 0); 7197 if (unlikely(running)) 7198 tsk->sched_class->put_prev_task(rq, tsk); 7199 7200 tg = container_of(task_css_check(tsk, cpu_cgrp_id, 7201 lockdep_is_held(&tsk->sighand->siglock)), 7202 struct task_group, css); 7203 tg = autogroup_task_group(tsk, tg); 7204 tsk->sched_task_group = tg; 7205 7206#ifdef CONFIG_FAIR_GROUP_SCHED 7207 if (tsk->sched_class->task_move_group) 7208 tsk->sched_class->task_move_group(tsk, on_rq); 7209 else 7210#endif 7211 set_task_rq(tsk, task_cpu(tsk)); 7212 7213 if (unlikely(running)) 7214 tsk->sched_class->set_curr_task(rq); 7215 if (on_rq) 7216 enqueue_task(rq, tsk, 0); 7217 7218 task_rq_unlock(rq, tsk, &flags); 7219} 7220#endif /* CONFIG_CGROUP_SCHED */ 7221 7222#ifdef CONFIG_RT_GROUP_SCHED 7223/* 7224 * Ensure that the real time constraints are schedulable. 7225 */ 7226static DEFINE_MUTEX(rt_constraints_mutex); 7227 7228/* Must be called with tasklist_lock held */ 7229static inline int tg_has_rt_tasks(struct task_group *tg) 7230{ 7231 struct task_struct *g, *p; 7232 7233 do_each_thread(g, p) { 7234 if (rt_task(p) && task_rq(p)->rt.tg == tg) 7235 return 1; 7236 } while_each_thread(g, p); 7237 7238 return 0; 7239} 7240 7241struct rt_schedulable_data { 7242 struct task_group *tg; 7243 u64 rt_period; 7244 u64 rt_runtime; 7245}; 7246 7247static int tg_rt_schedulable(struct task_group *tg, void *data) 7248{ 7249 struct rt_schedulable_data *d = data; 7250 struct task_group *child; 7251 unsigned long total, sum = 0; 7252 u64 period, runtime; 7253 7254 period = ktime_to_ns(tg->rt_bandwidth.rt_period); 7255 runtime = tg->rt_bandwidth.rt_runtime; 7256 7257 if (tg == d->tg) { 7258 period = d->rt_period; 7259 runtime = d->rt_runtime; 7260 } 7261 7262 /* 7263 * Cannot have more runtime than the period. 7264 */ 7265 if (runtime > period && runtime != RUNTIME_INF) 7266 return -EINVAL; 7267 7268 /* 7269 * Ensure we don't starve existing RT tasks. 7270 */ 7271 if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg)) 7272 return -EBUSY; 7273 7274 total = to_ratio(period, runtime); 7275 7276 /* 7277 * Nobody can have more than the global setting allows. 7278 */ 7279 if (total > to_ratio(global_rt_period(), global_rt_runtime())) 7280 return -EINVAL; 7281 7282 /* 7283 * The sum of our children's runtime should not exceed our own. 7284 */ 7285 list_for_each_entry_rcu(child, &tg->children, siblings) { 7286 period = ktime_to_ns(child->rt_bandwidth.rt_period); 7287 runtime = child->rt_bandwidth.rt_runtime; 7288 7289 if (child == d->tg) { 7290 period = d->rt_period; 7291 runtime = d->rt_runtime; 7292 } 7293 7294 sum += to_ratio(period, runtime); 7295 } 7296 7297 if (sum > total) 7298 return -EINVAL; 7299 7300 return 0; 7301} 7302 7303static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime) 7304{ 7305 int ret; 7306 7307 struct rt_schedulable_data data = { 7308 .tg = tg, 7309 .rt_period = period, 7310 .rt_runtime = runtime, 7311 }; 7312 7313 rcu_read_lock(); 7314 ret = walk_tg_tree(tg_rt_schedulable, tg_nop, &data); 7315 rcu_read_unlock(); 7316 7317 return ret; 7318} 7319 7320static int tg_set_rt_bandwidth(struct task_group *tg, 7321 u64 rt_period, u64 rt_runtime) 7322{ 7323 int i, err = 0; 7324 7325 mutex_lock(&rt_constraints_mutex); 7326 read_lock(&tasklist_lock); 7327 err = __rt_schedulable(tg, rt_period, rt_runtime); 7328 if (err) 7329 goto unlock; 7330 7331 raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock); 7332 tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period); 7333 tg->rt_bandwidth.rt_runtime = rt_runtime; 7334 7335 for_each_possible_cpu(i) { 7336 struct rt_rq *rt_rq = tg->rt_rq[i]; 7337 7338 raw_spin_lock(&rt_rq->rt_runtime_lock); 7339 rt_rq->rt_runtime = rt_runtime; 7340 raw_spin_unlock(&rt_rq->rt_runtime_lock); 7341 } 7342 raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock); 7343unlock: 7344 read_unlock(&tasklist_lock); 7345 mutex_unlock(&rt_constraints_mutex); 7346 7347 return err; 7348} 7349 7350static int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us) 7351{ 7352 u64 rt_runtime, rt_period; 7353 7354 rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period); 7355 rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC; 7356 if (rt_runtime_us < 0) 7357 rt_runtime = RUNTIME_INF; 7358 7359 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); 7360} 7361 7362static long sched_group_rt_runtime(struct task_group *tg) 7363{ 7364 u64 rt_runtime_us; 7365 7366 if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF) 7367 return -1; 7368 7369 rt_runtime_us = tg->rt_bandwidth.rt_runtime; 7370 do_div(rt_runtime_us, NSEC_PER_USEC); 7371 return rt_runtime_us; 7372} 7373 7374static int sched_group_set_rt_period(struct task_group *tg, long rt_period_us) 7375{ 7376 u64 rt_runtime, rt_period; 7377 7378 rt_period = (u64)rt_period_us * NSEC_PER_USEC; 7379 rt_runtime = tg->rt_bandwidth.rt_runtime; 7380 7381 if (rt_period == 0) 7382 return -EINVAL; 7383 7384 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); 7385} 7386 7387static long sched_group_rt_period(struct task_group *tg) 7388{ 7389 u64 rt_period_us; 7390 7391 rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period); 7392 do_div(rt_period_us, NSEC_PER_USEC); 7393 return rt_period_us; 7394} 7395#endif /* CONFIG_RT_GROUP_SCHED */ 7396 7397#ifdef CONFIG_RT_GROUP_SCHED 7398static int sched_rt_global_constraints(void) 7399{ 7400 int ret = 0; 7401 7402 mutex_lock(&rt_constraints_mutex); 7403 read_lock(&tasklist_lock); 7404 ret = __rt_schedulable(NULL, 0, 0); 7405 read_unlock(&tasklist_lock); 7406 mutex_unlock(&rt_constraints_mutex); 7407 7408 return ret; 7409} 7410 7411static int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk) 7412{ 7413 /* Don't accept realtime tasks when there is no way for them to run */ 7414 if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0) 7415 return 0; 7416 7417 return 1; 7418} 7419 7420#else /* !CONFIG_RT_GROUP_SCHED */ 7421static int sched_rt_global_constraints(void) 7422{ 7423 unsigned long flags; 7424 int i, ret = 0; 7425 7426 raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags); 7427 for_each_possible_cpu(i) { 7428 struct rt_rq *rt_rq = &cpu_rq(i)->rt; 7429 7430 raw_spin_lock(&rt_rq->rt_runtime_lock); 7431 rt_rq->rt_runtime = global_rt_runtime(); 7432 raw_spin_unlock(&rt_rq->rt_runtime_lock); 7433 } 7434 raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags); 7435 7436 return ret; 7437} 7438#endif /* CONFIG_RT_GROUP_SCHED */ 7439 7440static int sched_dl_global_constraints(void) 7441{ 7442 u64 runtime = global_rt_runtime(); 7443 u64 period = global_rt_period(); 7444 u64 new_bw = to_ratio(period, runtime); 7445 int cpu, ret = 0; 7446 unsigned long flags; 7447 7448 /* 7449 * Here we want to check the bandwidth not being set to some 7450 * value smaller than the currently allocated bandwidth in 7451 * any of the root_domains. 7452 * 7453 * FIXME: Cycling on all the CPUs is overdoing, but simpler than 7454 * cycling on root_domains... Discussion on different/better 7455 * solutions is welcome! 7456 */ 7457 for_each_possible_cpu(cpu) { 7458 struct dl_bw *dl_b = dl_bw_of(cpu); 7459 7460 raw_spin_lock_irqsave(&dl_b->lock, flags); 7461 if (new_bw < dl_b->total_bw) 7462 ret = -EBUSY; 7463 raw_spin_unlock_irqrestore(&dl_b->lock, flags); 7464 7465 if (ret) 7466 break; 7467 } 7468 7469 return ret; 7470} 7471 7472static void sched_dl_do_global(void) 7473{ 7474 u64 new_bw = -1; 7475 int cpu; 7476 unsigned long flags; 7477 7478 def_dl_bandwidth.dl_period = global_rt_period(); 7479 def_dl_bandwidth.dl_runtime = global_rt_runtime(); 7480 7481 if (global_rt_runtime() != RUNTIME_INF) 7482 new_bw = to_ratio(global_rt_period(), global_rt_runtime()); 7483 7484 /* 7485 * FIXME: As above... 7486 */ 7487 for_each_possible_cpu(cpu) { 7488 struct dl_bw *dl_b = dl_bw_of(cpu); 7489 7490 raw_spin_lock_irqsave(&dl_b->lock, flags); 7491 dl_b->bw = new_bw; 7492 raw_spin_unlock_irqrestore(&dl_b->lock, flags); 7493 } 7494} 7495 7496static int sched_rt_global_validate(void) 7497{ 7498 if (sysctl_sched_rt_period <= 0) 7499 return -EINVAL; 7500 7501 if ((sysctl_sched_rt_runtime != RUNTIME_INF) && 7502 (sysctl_sched_rt_runtime > sysctl_sched_rt_period)) 7503 return -EINVAL; 7504 7505 return 0; 7506} 7507 7508static void sched_rt_do_global(void) 7509{ 7510 def_rt_bandwidth.rt_runtime = global_rt_runtime(); 7511 def_rt_bandwidth.rt_period = ns_to_ktime(global_rt_period()); 7512} 7513 7514int sched_rt_handler(struct ctl_table *table, int write, 7515 void __user *buffer, size_t *lenp, 7516 loff_t *ppos) 7517{ 7518 int old_period, old_runtime; 7519 static DEFINE_MUTEX(mutex); 7520 int ret; 7521 7522 mutex_lock(&mutex); 7523 old_period = sysctl_sched_rt_period; 7524 old_runtime = sysctl_sched_rt_runtime; 7525 7526 ret = proc_dointvec(table, write, buffer, lenp, ppos); 7527 7528 if (!ret && write) { 7529 ret = sched_rt_global_validate(); 7530 if (ret) 7531 goto undo; 7532 7533 ret = sched_rt_global_constraints(); 7534 if (ret) 7535 goto undo; 7536 7537 ret = sched_dl_global_constraints(); 7538 if (ret) 7539 goto undo; 7540 7541 sched_rt_do_global(); 7542 sched_dl_do_global(); 7543 } 7544 if (0) { 7545undo: 7546 sysctl_sched_rt_period = old_period; 7547 sysctl_sched_rt_runtime = old_runtime; 7548 } 7549 mutex_unlock(&mutex); 7550 7551 return ret; 7552} 7553 7554int sched_rr_handler(struct ctl_table *table, int write, 7555 void __user *buffer, size_t *lenp, 7556 loff_t *ppos) 7557{ 7558 int ret; 7559 static DEFINE_MUTEX(mutex); 7560 7561 mutex_lock(&mutex); 7562 ret = proc_dointvec(table, write, buffer, lenp, ppos); 7563 /* make sure that internally we keep jiffies */ 7564 /* also, writing zero resets timeslice to default */ 7565 if (!ret && write) { 7566 sched_rr_timeslice = sched_rr_timeslice <= 0 ? 7567 RR_TIMESLICE : msecs_to_jiffies(sched_rr_timeslice); 7568 } 7569 mutex_unlock(&mutex); 7570 return ret; 7571} 7572 7573#ifdef CONFIG_CGROUP_SCHED 7574 7575static inline struct task_group *css_tg(struct cgroup_subsys_state *css) 7576{ 7577 return css ? container_of(css, struct task_group, css) : NULL; 7578} 7579 7580static struct cgroup_subsys_state * 7581cpu_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) 7582{ 7583 struct task_group *parent = css_tg(parent_css); 7584 struct task_group *tg; 7585 7586 if (!parent) { 7587 /* This is early initialization for the top cgroup */ 7588 return &root_task_group.css; 7589 } 7590 7591 tg = sched_create_group(parent); 7592 if (IS_ERR(tg)) 7593 return ERR_PTR(-ENOMEM); 7594 7595 return &tg->css; 7596} 7597 7598static int cpu_cgroup_css_online(struct cgroup_subsys_state *css) 7599{ 7600 struct task_group *tg = css_tg(css); 7601 struct task_group *parent = css_tg(css_parent(css)); 7602 7603 if (parent) 7604 sched_online_group(tg, parent); 7605 return 0; 7606} 7607 7608static void cpu_cgroup_css_free(struct cgroup_subsys_state *css) 7609{ 7610 struct task_group *tg = css_tg(css); 7611 7612 sched_destroy_group(tg); 7613} 7614 7615static void cpu_cgroup_css_offline(struct cgroup_subsys_state *css) 7616{ 7617 struct task_group *tg = css_tg(css); 7618 7619 sched_offline_group(tg); 7620} 7621 7622static int cpu_cgroup_can_attach(struct cgroup_subsys_state *css, 7623 struct cgroup_taskset *tset) 7624{ 7625 struct task_struct *task; 7626 7627 cgroup_taskset_for_each(task, tset) { 7628#ifdef CONFIG_RT_GROUP_SCHED 7629 if (!sched_rt_can_attach(css_tg(css), task)) 7630 return -EINVAL; 7631#else 7632 /* We don't support RT-tasks being in separate groups */ 7633 if (task->sched_class != &fair_sched_class) 7634 return -EINVAL; 7635#endif 7636 } 7637 return 0; 7638} 7639 7640static void cpu_cgroup_attach(struct cgroup_subsys_state *css, 7641 struct cgroup_taskset *tset) 7642{ 7643 struct task_struct *task; 7644 7645 cgroup_taskset_for_each(task, tset) 7646 sched_move_task(task); 7647} 7648 7649static void cpu_cgroup_exit(struct cgroup_subsys_state *css, 7650 struct cgroup_subsys_state *old_css, 7651 struct task_struct *task) 7652{ 7653 /* 7654 * cgroup_exit() is called in the copy_process() failure path. 7655 * Ignore this case since the task hasn't ran yet, this avoids 7656 * trying to poke a half freed task state from generic code. 7657 */ 7658 if (!(task->flags & PF_EXITING)) 7659 return; 7660 7661 sched_move_task(task); 7662} 7663 7664#ifdef CONFIG_FAIR_GROUP_SCHED 7665static int cpu_shares_write_u64(struct cgroup_subsys_state *css, 7666 struct cftype *cftype, u64 shareval) 7667{ 7668 return sched_group_set_shares(css_tg(css), scale_load(shareval)); 7669} 7670 7671static u64 cpu_shares_read_u64(struct cgroup_subsys_state *css, 7672 struct cftype *cft) 7673{ 7674 struct task_group *tg = css_tg(css); 7675 7676 return (u64) scale_load_down(tg->shares); 7677} 7678 7679#ifdef CONFIG_CFS_BANDWIDTH 7680static DEFINE_MUTEX(cfs_constraints_mutex); 7681 7682const u64 max_cfs_quota_period = 1 * NSEC_PER_SEC; /* 1s */ 7683const u64 min_cfs_quota_period = 1 * NSEC_PER_MSEC; /* 1ms */ 7684 7685static int __cfs_schedulable(struct task_group *tg, u64 period, u64 runtime); 7686 7687static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota) 7688{ 7689 int i, ret = 0, runtime_enabled, runtime_was_enabled; 7690 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 7691 7692 if (tg == &root_task_group) 7693 return -EINVAL; 7694 7695 /* 7696 * Ensure we have at some amount of bandwidth every period. This is 7697 * to prevent reaching a state of large arrears when throttled via 7698 * entity_tick() resulting in prolonged exit starvation. 7699 */ 7700 if (quota < min_cfs_quota_period || period < min_cfs_quota_period) 7701 return -EINVAL; 7702 7703 /* 7704 * Likewise, bound things on the otherside by preventing insane quota 7705 * periods. This also allows us to normalize in computing quota 7706 * feasibility. 7707 */ 7708 if (period > max_cfs_quota_period) 7709 return -EINVAL; 7710 7711 mutex_lock(&cfs_constraints_mutex); 7712 ret = __cfs_schedulable(tg, period, quota); 7713 if (ret) 7714 goto out_unlock; 7715 7716 runtime_enabled = quota != RUNTIME_INF; 7717 runtime_was_enabled = cfs_b->quota != RUNTIME_INF; 7718 /* 7719 * If we need to toggle cfs_bandwidth_used, off->on must occur 7720 * before making related changes, and on->off must occur afterwards 7721 */ 7722 if (runtime_enabled && !runtime_was_enabled) 7723 cfs_bandwidth_usage_inc(); 7724 raw_spin_lock_irq(&cfs_b->lock); 7725 cfs_b->period = ns_to_ktime(period); 7726 cfs_b->quota = quota; 7727 7728 __refill_cfs_bandwidth_runtime(cfs_b); 7729 /* restart the period timer (if active) to handle new period expiry */ 7730 if (runtime_enabled && cfs_b->timer_active) { 7731 /* force a reprogram */ 7732 cfs_b->timer_active = 0; 7733 __start_cfs_bandwidth(cfs_b); 7734 } 7735 raw_spin_unlock_irq(&cfs_b->lock); 7736 7737 for_each_possible_cpu(i) { 7738 struct cfs_rq *cfs_rq = tg->cfs_rq[i]; 7739 struct rq *rq = cfs_rq->rq; 7740 7741 raw_spin_lock_irq(&rq->lock); 7742 cfs_rq->runtime_enabled = runtime_enabled; 7743 cfs_rq->runtime_remaining = 0; 7744 7745 if (cfs_rq->throttled) 7746 unthrottle_cfs_rq(cfs_rq); 7747 raw_spin_unlock_irq(&rq->lock); 7748 } 7749 if (runtime_was_enabled && !runtime_enabled) 7750 cfs_bandwidth_usage_dec(); 7751out_unlock: 7752 mutex_unlock(&cfs_constraints_mutex); 7753 7754 return ret; 7755} 7756 7757int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us) 7758{ 7759 u64 quota, period; 7760 7761 period = ktime_to_ns(tg->cfs_bandwidth.period); 7762 if (cfs_quota_us < 0) 7763 quota = RUNTIME_INF; 7764 else 7765 quota = (u64)cfs_quota_us * NSEC_PER_USEC; 7766 7767 return tg_set_cfs_bandwidth(tg, period, quota); 7768} 7769 7770long tg_get_cfs_quota(struct task_group *tg) 7771{ 7772 u64 quota_us; 7773 7774 if (tg->cfs_bandwidth.quota == RUNTIME_INF) 7775 return -1; 7776 7777 quota_us = tg->cfs_bandwidth.quota; 7778 do_div(quota_us, NSEC_PER_USEC); 7779 7780 return quota_us; 7781} 7782 7783int tg_set_cfs_period(struct task_group *tg, long cfs_period_us) 7784{ 7785 u64 quota, period; 7786 7787 period = (u64)cfs_period_us * NSEC_PER_USEC; 7788 quota = tg->cfs_bandwidth.quota; 7789 7790 return tg_set_cfs_bandwidth(tg, period, quota); 7791} 7792 7793long tg_get_cfs_period(struct task_group *tg) 7794{ 7795 u64 cfs_period_us; 7796 7797 cfs_period_us = ktime_to_ns(tg->cfs_bandwidth.period); 7798 do_div(cfs_period_us, NSEC_PER_USEC); 7799 7800 return cfs_period_us; 7801} 7802 7803static s64 cpu_cfs_quota_read_s64(struct cgroup_subsys_state *css, 7804 struct cftype *cft) 7805{ 7806 return tg_get_cfs_quota(css_tg(css)); 7807} 7808 7809static int cpu_cfs_quota_write_s64(struct cgroup_subsys_state *css, 7810 struct cftype *cftype, s64 cfs_quota_us) 7811{ 7812 return tg_set_cfs_quota(css_tg(css), cfs_quota_us); 7813} 7814 7815static u64 cpu_cfs_period_read_u64(struct cgroup_subsys_state *css, 7816 struct cftype *cft) 7817{ 7818 return tg_get_cfs_period(css_tg(css)); 7819} 7820 7821static int cpu_cfs_period_write_u64(struct cgroup_subsys_state *css, 7822 struct cftype *cftype, u64 cfs_period_us) 7823{ 7824 return tg_set_cfs_period(css_tg(css), cfs_period_us); 7825} 7826 7827struct cfs_schedulable_data { 7828 struct task_group *tg; 7829 u64 period, quota; 7830}; 7831 7832/* 7833 * normalize group quota/period to be quota/max_period 7834 * note: units are usecs 7835 */ 7836static u64 normalize_cfs_quota(struct task_group *tg, 7837 struct cfs_schedulable_data *d) 7838{ 7839 u64 quota, period; 7840 7841 if (tg == d->tg) { 7842 period = d->period; 7843 quota = d->quota; 7844 } else { 7845 period = tg_get_cfs_period(tg); 7846 quota = tg_get_cfs_quota(tg); 7847 } 7848 7849 /* note: these should typically be equivalent */ 7850 if (quota == RUNTIME_INF || quota == -1) 7851 return RUNTIME_INF; 7852 7853 return to_ratio(period, quota); 7854} 7855 7856static int tg_cfs_schedulable_down(struct task_group *tg, void *data) 7857{ 7858 struct cfs_schedulable_data *d = data; 7859 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 7860 s64 quota = 0, parent_quota = -1; 7861 7862 if (!tg->parent) { 7863 quota = RUNTIME_INF; 7864 } else { 7865 struct cfs_bandwidth *parent_b = &tg->parent->cfs_bandwidth; 7866 7867 quota = normalize_cfs_quota(tg, d); 7868 parent_quota = parent_b->hierarchal_quota; 7869 7870 /* 7871 * ensure max(child_quota) <= parent_quota, inherit when no 7872 * limit is set 7873 */ 7874 if (quota == RUNTIME_INF) 7875 quota = parent_quota; 7876 else if (parent_quota != RUNTIME_INF && quota > parent_quota) 7877 return -EINVAL; 7878 } 7879 cfs_b->hierarchal_quota = quota; 7880 7881 return 0; 7882} 7883 7884static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota) 7885{ 7886 int ret; 7887 struct cfs_schedulable_data data = { 7888 .tg = tg, 7889 .period = period, 7890 .quota = quota, 7891 }; 7892 7893 if (quota != RUNTIME_INF) { 7894 do_div(data.period, NSEC_PER_USEC); 7895 do_div(data.quota, NSEC_PER_USEC); 7896 } 7897 7898 rcu_read_lock(); 7899 ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data); 7900 rcu_read_unlock(); 7901 7902 return ret; 7903} 7904 7905static int cpu_stats_show(struct seq_file *sf, void *v) 7906{ 7907 struct task_group *tg = css_tg(seq_css(sf)); 7908 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 7909 7910 seq_printf(sf, "nr_periods %d\n", cfs_b->nr_periods); 7911 seq_printf(sf, "nr_throttled %d\n", cfs_b->nr_throttled); 7912 seq_printf(sf, "throttled_time %llu\n", cfs_b->throttled_time); 7913 7914 return 0; 7915} 7916#endif /* CONFIG_CFS_BANDWIDTH */ 7917#endif /* CONFIG_FAIR_GROUP_SCHED */ 7918 7919#ifdef CONFIG_RT_GROUP_SCHED 7920static int cpu_rt_runtime_write(struct cgroup_subsys_state *css, 7921 struct cftype *cft, s64 val) 7922{ 7923 return sched_group_set_rt_runtime(css_tg(css), val); 7924} 7925 7926static s64 cpu_rt_runtime_read(struct cgroup_subsys_state *css, 7927 struct cftype *cft) 7928{ 7929 return sched_group_rt_runtime(css_tg(css)); 7930} 7931 7932static int cpu_rt_period_write_uint(struct cgroup_subsys_state *css, 7933 struct cftype *cftype, u64 rt_period_us) 7934{ 7935 return sched_group_set_rt_period(css_tg(css), rt_period_us); 7936} 7937 7938static u64 cpu_rt_period_read_uint(struct cgroup_subsys_state *css, 7939 struct cftype *cft) 7940{ 7941 return sched_group_rt_period(css_tg(css)); 7942} 7943#endif /* CONFIG_RT_GROUP_SCHED */ 7944 7945static struct cftype cpu_files[] = { 7946#ifdef CONFIG_FAIR_GROUP_SCHED 7947 { 7948 .name = "shares", 7949 .read_u64 = cpu_shares_read_u64, 7950 .write_u64 = cpu_shares_write_u64, 7951 }, 7952#endif 7953#ifdef CONFIG_CFS_BANDWIDTH 7954 { 7955 .name = "cfs_quota_us", 7956 .read_s64 = cpu_cfs_quota_read_s64, 7957 .write_s64 = cpu_cfs_quota_write_s64, 7958 }, 7959 { 7960 .name = "cfs_period_us", 7961 .read_u64 = cpu_cfs_period_read_u64, 7962 .write_u64 = cpu_cfs_period_write_u64, 7963 }, 7964 { 7965 .name = "stat", 7966 .seq_show = cpu_stats_show, 7967 }, 7968#endif 7969#ifdef CONFIG_RT_GROUP_SCHED 7970 { 7971 .name = "rt_runtime_us", 7972 .read_s64 = cpu_rt_runtime_read, 7973 .write_s64 = cpu_rt_runtime_write, 7974 }, 7975 { 7976 .name = "rt_period_us", 7977 .read_u64 = cpu_rt_period_read_uint, 7978 .write_u64 = cpu_rt_period_write_uint, 7979 }, 7980#endif 7981 { } /* terminate */ 7982}; 7983 7984struct cgroup_subsys cpu_cgrp_subsys = { 7985 .css_alloc = cpu_cgroup_css_alloc, 7986 .css_free = cpu_cgroup_css_free, 7987 .css_online = cpu_cgroup_css_online, 7988 .css_offline = cpu_cgroup_css_offline, 7989 .can_attach = cpu_cgroup_can_attach, 7990 .attach = cpu_cgroup_attach, 7991 .exit = cpu_cgroup_exit, 7992 .base_cftypes = cpu_files, 7993 .early_init = 1, 7994}; 7995 7996#endif /* CONFIG_CGROUP_SCHED */ 7997 7998void dump_cpu_task(int cpu) 7999{ 8000 pr_info("Task dump for CPU %d:\n", cpu); 8001 sched_show_task(cpu_curr(cpu)); 8002} 8003