core.c revision b0827819b0da4acfbc1df1e05edcf50efd07cbd1
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 of 1us (we 3199 * check sched_runtime only since it is always the smaller one) and 3200 * below 2^63 ns (we have to check both sched_deadline and 3201 * sched_period, as the latter can be zero). 3202 */ 3203static bool 3204__checkparam_dl(const struct sched_attr *attr) 3205{ 3206 /* deadline != 0 */ 3207 if (attr->sched_deadline == 0) 3208 return false; 3209 3210 /* 3211 * Since we truncate DL_SCALE bits, make sure we're at least 3212 * that big. 3213 */ 3214 if (attr->sched_runtime < (1ULL << DL_SCALE)) 3215 return false; 3216 3217 /* 3218 * Since we use the MSB for wrap-around and sign issues, make 3219 * sure it's not set (mind that period can be equal to zero). 3220 */ 3221 if (attr->sched_deadline & (1ULL << 63) || 3222 attr->sched_period & (1ULL << 63)) 3223 return false; 3224 3225 /* runtime <= deadline <= period (if period != 0) */ 3226 if ((attr->sched_period != 0 && 3227 attr->sched_period < attr->sched_deadline) || 3228 attr->sched_deadline < attr->sched_runtime) 3229 return false; 3230 3231 return true; 3232} 3233 3234/* 3235 * check the target process has a UID that matches the current process's 3236 */ 3237static bool check_same_owner(struct task_struct *p) 3238{ 3239 const struct cred *cred = current_cred(), *pcred; 3240 bool match; 3241 3242 rcu_read_lock(); 3243 pcred = __task_cred(p); 3244 match = (uid_eq(cred->euid, pcred->euid) || 3245 uid_eq(cred->euid, pcred->uid)); 3246 rcu_read_unlock(); 3247 return match; 3248} 3249 3250static int __sched_setscheduler(struct task_struct *p, 3251 const struct sched_attr *attr, 3252 bool user) 3253{ 3254 int newprio = dl_policy(attr->sched_policy) ? MAX_DL_PRIO - 1 : 3255 MAX_RT_PRIO - 1 - attr->sched_priority; 3256 int retval, oldprio, oldpolicy = -1, on_rq, running; 3257 int policy = attr->sched_policy; 3258 unsigned long flags; 3259 const struct sched_class *prev_class; 3260 struct rq *rq; 3261 int reset_on_fork; 3262 3263 /* may grab non-irq protected spin_locks */ 3264 BUG_ON(in_interrupt()); 3265recheck: 3266 /* double check policy once rq lock held */ 3267 if (policy < 0) { 3268 reset_on_fork = p->sched_reset_on_fork; 3269 policy = oldpolicy = p->policy; 3270 } else { 3271 reset_on_fork = !!(attr->sched_flags & SCHED_FLAG_RESET_ON_FORK); 3272 3273 if (policy != SCHED_DEADLINE && 3274 policy != SCHED_FIFO && policy != SCHED_RR && 3275 policy != SCHED_NORMAL && policy != SCHED_BATCH && 3276 policy != SCHED_IDLE) 3277 return -EINVAL; 3278 } 3279 3280 if (attr->sched_flags & ~(SCHED_FLAG_RESET_ON_FORK)) 3281 return -EINVAL; 3282 3283 /* 3284 * Valid priorities for SCHED_FIFO and SCHED_RR are 3285 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL, 3286 * SCHED_BATCH and SCHED_IDLE is 0. 3287 */ 3288 if ((p->mm && attr->sched_priority > MAX_USER_RT_PRIO-1) || 3289 (!p->mm && attr->sched_priority > MAX_RT_PRIO-1)) 3290 return -EINVAL; 3291 if ((dl_policy(policy) && !__checkparam_dl(attr)) || 3292 (rt_policy(policy) != (attr->sched_priority != 0))) 3293 return -EINVAL; 3294 3295 /* 3296 * Allow unprivileged RT tasks to decrease priority: 3297 */ 3298 if (user && !capable(CAP_SYS_NICE)) { 3299 if (fair_policy(policy)) { 3300 if (attr->sched_nice < task_nice(p) && 3301 !can_nice(p, attr->sched_nice)) 3302 return -EPERM; 3303 } 3304 3305 if (rt_policy(policy)) { 3306 unsigned long rlim_rtprio = 3307 task_rlimit(p, RLIMIT_RTPRIO); 3308 3309 /* can't set/change the rt policy */ 3310 if (policy != p->policy && !rlim_rtprio) 3311 return -EPERM; 3312 3313 /* can't increase priority */ 3314 if (attr->sched_priority > p->rt_priority && 3315 attr->sched_priority > rlim_rtprio) 3316 return -EPERM; 3317 } 3318 3319 /* 3320 * Can't set/change SCHED_DEADLINE policy at all for now 3321 * (safest behavior); in the future we would like to allow 3322 * unprivileged DL tasks to increase their relative deadline 3323 * or reduce their runtime (both ways reducing utilization) 3324 */ 3325 if (dl_policy(policy)) 3326 return -EPERM; 3327 3328 /* 3329 * Treat SCHED_IDLE as nice 20. Only allow a switch to 3330 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it. 3331 */ 3332 if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) { 3333 if (!can_nice(p, task_nice(p))) 3334 return -EPERM; 3335 } 3336 3337 /* can't change other user's priorities */ 3338 if (!check_same_owner(p)) 3339 return -EPERM; 3340 3341 /* Normal users shall not reset the sched_reset_on_fork flag */ 3342 if (p->sched_reset_on_fork && !reset_on_fork) 3343 return -EPERM; 3344 } 3345 3346 if (user) { 3347 retval = security_task_setscheduler(p); 3348 if (retval) 3349 return retval; 3350 } 3351 3352 /* 3353 * make sure no PI-waiters arrive (or leave) while we are 3354 * changing the priority of the task: 3355 * 3356 * To be able to change p->policy safely, the appropriate 3357 * runqueue lock must be held. 3358 */ 3359 rq = task_rq_lock(p, &flags); 3360 3361 /* 3362 * Changing the policy of the stop threads its a very bad idea 3363 */ 3364 if (p == rq->stop) { 3365 task_rq_unlock(rq, p, &flags); 3366 return -EINVAL; 3367 } 3368 3369 /* 3370 * If not changing anything there's no need to proceed further, 3371 * but store a possible modification of reset_on_fork. 3372 */ 3373 if (unlikely(policy == p->policy)) { 3374 if (fair_policy(policy) && attr->sched_nice != task_nice(p)) 3375 goto change; 3376 if (rt_policy(policy) && attr->sched_priority != p->rt_priority) 3377 goto change; 3378 if (dl_policy(policy)) 3379 goto change; 3380 3381 p->sched_reset_on_fork = reset_on_fork; 3382 task_rq_unlock(rq, p, &flags); 3383 return 0; 3384 } 3385change: 3386 3387 if (user) { 3388#ifdef CONFIG_RT_GROUP_SCHED 3389 /* 3390 * Do not allow realtime tasks into groups that have no runtime 3391 * assigned. 3392 */ 3393 if (rt_bandwidth_enabled() && rt_policy(policy) && 3394 task_group(p)->rt_bandwidth.rt_runtime == 0 && 3395 !task_group_is_autogroup(task_group(p))) { 3396 task_rq_unlock(rq, p, &flags); 3397 return -EPERM; 3398 } 3399#endif 3400#ifdef CONFIG_SMP 3401 if (dl_bandwidth_enabled() && dl_policy(policy)) { 3402 cpumask_t *span = rq->rd->span; 3403 3404 /* 3405 * Don't allow tasks with an affinity mask smaller than 3406 * the entire root_domain to become SCHED_DEADLINE. We 3407 * will also fail if there's no bandwidth available. 3408 */ 3409 if (!cpumask_subset(span, &p->cpus_allowed) || 3410 rq->rd->dl_bw.bw == 0) { 3411 task_rq_unlock(rq, p, &flags); 3412 return -EPERM; 3413 } 3414 } 3415#endif 3416 } 3417 3418 /* recheck policy now with rq lock held */ 3419 if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { 3420 policy = oldpolicy = -1; 3421 task_rq_unlock(rq, p, &flags); 3422 goto recheck; 3423 } 3424 3425 /* 3426 * If setscheduling to SCHED_DEADLINE (or changing the parameters 3427 * of a SCHED_DEADLINE task) we need to check if enough bandwidth 3428 * is available. 3429 */ 3430 if ((dl_policy(policy) || dl_task(p)) && dl_overflow(p, policy, attr)) { 3431 task_rq_unlock(rq, p, &flags); 3432 return -EBUSY; 3433 } 3434 3435 p->sched_reset_on_fork = reset_on_fork; 3436 oldprio = p->prio; 3437 3438 /* 3439 * Special case for priority boosted tasks. 3440 * 3441 * If the new priority is lower or equal (user space view) 3442 * than the current (boosted) priority, we just store the new 3443 * normal parameters and do not touch the scheduler class and 3444 * the runqueue. This will be done when the task deboost 3445 * itself. 3446 */ 3447 if (rt_mutex_check_prio(p, newprio)) { 3448 __setscheduler_params(p, attr); 3449 task_rq_unlock(rq, p, &flags); 3450 return 0; 3451 } 3452 3453 on_rq = p->on_rq; 3454 running = task_current(rq, p); 3455 if (on_rq) 3456 dequeue_task(rq, p, 0); 3457 if (running) 3458 p->sched_class->put_prev_task(rq, p); 3459 3460 prev_class = p->sched_class; 3461 __setscheduler(rq, p, attr); 3462 3463 if (running) 3464 p->sched_class->set_curr_task(rq); 3465 if (on_rq) { 3466 /* 3467 * We enqueue to tail when the priority of a task is 3468 * increased (user space view). 3469 */ 3470 enqueue_task(rq, p, oldprio <= p->prio ? ENQUEUE_HEAD : 0); 3471 } 3472 3473 check_class_changed(rq, p, prev_class, oldprio); 3474 task_rq_unlock(rq, p, &flags); 3475 3476 rt_mutex_adjust_pi(p); 3477 3478 return 0; 3479} 3480 3481static int _sched_setscheduler(struct task_struct *p, int policy, 3482 const struct sched_param *param, bool check) 3483{ 3484 struct sched_attr attr = { 3485 .sched_policy = policy, 3486 .sched_priority = param->sched_priority, 3487 .sched_nice = PRIO_TO_NICE(p->static_prio), 3488 }; 3489 3490 /* 3491 * Fixup the legacy SCHED_RESET_ON_FORK hack 3492 */ 3493 if (policy & SCHED_RESET_ON_FORK) { 3494 attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK; 3495 policy &= ~SCHED_RESET_ON_FORK; 3496 attr.sched_policy = policy; 3497 } 3498 3499 return __sched_setscheduler(p, &attr, check); 3500} 3501/** 3502 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. 3503 * @p: the task in question. 3504 * @policy: new policy. 3505 * @param: structure containing the new RT priority. 3506 * 3507 * Return: 0 on success. An error code otherwise. 3508 * 3509 * NOTE that the task may be already dead. 3510 */ 3511int sched_setscheduler(struct task_struct *p, int policy, 3512 const struct sched_param *param) 3513{ 3514 return _sched_setscheduler(p, policy, param, true); 3515} 3516EXPORT_SYMBOL_GPL(sched_setscheduler); 3517 3518int sched_setattr(struct task_struct *p, const struct sched_attr *attr) 3519{ 3520 return __sched_setscheduler(p, attr, true); 3521} 3522EXPORT_SYMBOL_GPL(sched_setattr); 3523 3524/** 3525 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace. 3526 * @p: the task in question. 3527 * @policy: new policy. 3528 * @param: structure containing the new RT priority. 3529 * 3530 * Just like sched_setscheduler, only don't bother checking if the 3531 * current context has permission. For example, this is needed in 3532 * stop_machine(): we create temporary high priority worker threads, 3533 * but our caller might not have that capability. 3534 * 3535 * Return: 0 on success. An error code otherwise. 3536 */ 3537int sched_setscheduler_nocheck(struct task_struct *p, int policy, 3538 const struct sched_param *param) 3539{ 3540 return _sched_setscheduler(p, policy, param, false); 3541} 3542 3543static int 3544do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) 3545{ 3546 struct sched_param lparam; 3547 struct task_struct *p; 3548 int retval; 3549 3550 if (!param || pid < 0) 3551 return -EINVAL; 3552 if (copy_from_user(&lparam, param, sizeof(struct sched_param))) 3553 return -EFAULT; 3554 3555 rcu_read_lock(); 3556 retval = -ESRCH; 3557 p = find_process_by_pid(pid); 3558 if (p != NULL) 3559 retval = sched_setscheduler(p, policy, &lparam); 3560 rcu_read_unlock(); 3561 3562 return retval; 3563} 3564 3565/* 3566 * Mimics kernel/events/core.c perf_copy_attr(). 3567 */ 3568static int sched_copy_attr(struct sched_attr __user *uattr, 3569 struct sched_attr *attr) 3570{ 3571 u32 size; 3572 int ret; 3573 3574 if (!access_ok(VERIFY_WRITE, uattr, SCHED_ATTR_SIZE_VER0)) 3575 return -EFAULT; 3576 3577 /* 3578 * zero the full structure, so that a short copy will be nice. 3579 */ 3580 memset(attr, 0, sizeof(*attr)); 3581 3582 ret = get_user(size, &uattr->size); 3583 if (ret) 3584 return ret; 3585 3586 if (size > PAGE_SIZE) /* silly large */ 3587 goto err_size; 3588 3589 if (!size) /* abi compat */ 3590 size = SCHED_ATTR_SIZE_VER0; 3591 3592 if (size < SCHED_ATTR_SIZE_VER0) 3593 goto err_size; 3594 3595 /* 3596 * If we're handed a bigger struct than we know of, 3597 * ensure all the unknown bits are 0 - i.e. new 3598 * user-space does not rely on any kernel feature 3599 * extensions we dont know about yet. 3600 */ 3601 if (size > sizeof(*attr)) { 3602 unsigned char __user *addr; 3603 unsigned char __user *end; 3604 unsigned char val; 3605 3606 addr = (void __user *)uattr + sizeof(*attr); 3607 end = (void __user *)uattr + size; 3608 3609 for (; addr < end; addr++) { 3610 ret = get_user(val, addr); 3611 if (ret) 3612 return ret; 3613 if (val) 3614 goto err_size; 3615 } 3616 size = sizeof(*attr); 3617 } 3618 3619 ret = copy_from_user(attr, uattr, size); 3620 if (ret) 3621 return -EFAULT; 3622 3623 /* 3624 * XXX: do we want to be lenient like existing syscalls; or do we want 3625 * to be strict and return an error on out-of-bounds values? 3626 */ 3627 attr->sched_nice = clamp(attr->sched_nice, MIN_NICE, MAX_NICE); 3628 3629out: 3630 return ret; 3631 3632err_size: 3633 put_user(sizeof(*attr), &uattr->size); 3634 ret = -E2BIG; 3635 goto out; 3636} 3637 3638/** 3639 * sys_sched_setscheduler - set/change the scheduler policy and RT priority 3640 * @pid: the pid in question. 3641 * @policy: new policy. 3642 * @param: structure containing the new RT priority. 3643 * 3644 * Return: 0 on success. An error code otherwise. 3645 */ 3646SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy, 3647 struct sched_param __user *, param) 3648{ 3649 /* negative values for policy are not valid */ 3650 if (policy < 0) 3651 return -EINVAL; 3652 3653 return do_sched_setscheduler(pid, policy, param); 3654} 3655 3656/** 3657 * sys_sched_setparam - set/change the RT priority of a thread 3658 * @pid: the pid in question. 3659 * @param: structure containing the new RT priority. 3660 * 3661 * Return: 0 on success. An error code otherwise. 3662 */ 3663SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param) 3664{ 3665 return do_sched_setscheduler(pid, -1, param); 3666} 3667 3668/** 3669 * sys_sched_setattr - same as above, but with extended sched_attr 3670 * @pid: the pid in question. 3671 * @uattr: structure containing the extended parameters. 3672 * @flags: for future extension. 3673 */ 3674SYSCALL_DEFINE3(sched_setattr, pid_t, pid, struct sched_attr __user *, uattr, 3675 unsigned int, flags) 3676{ 3677 struct sched_attr attr; 3678 struct task_struct *p; 3679 int retval; 3680 3681 if (!uattr || pid < 0 || flags) 3682 return -EINVAL; 3683 3684 retval = sched_copy_attr(uattr, &attr); 3685 if (retval) 3686 return retval; 3687 3688 if (attr.sched_policy < 0) 3689 return -EINVAL; 3690 3691 rcu_read_lock(); 3692 retval = -ESRCH; 3693 p = find_process_by_pid(pid); 3694 if (p != NULL) 3695 retval = sched_setattr(p, &attr); 3696 rcu_read_unlock(); 3697 3698 return retval; 3699} 3700 3701/** 3702 * sys_sched_getscheduler - get the policy (scheduling class) of a thread 3703 * @pid: the pid in question. 3704 * 3705 * Return: On success, the policy of the thread. Otherwise, a negative error 3706 * code. 3707 */ 3708SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid) 3709{ 3710 struct task_struct *p; 3711 int retval; 3712 3713 if (pid < 0) 3714 return -EINVAL; 3715 3716 retval = -ESRCH; 3717 rcu_read_lock(); 3718 p = find_process_by_pid(pid); 3719 if (p) { 3720 retval = security_task_getscheduler(p); 3721 if (!retval) 3722 retval = p->policy 3723 | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0); 3724 } 3725 rcu_read_unlock(); 3726 return retval; 3727} 3728 3729/** 3730 * sys_sched_getparam - get the RT priority of a thread 3731 * @pid: the pid in question. 3732 * @param: structure containing the RT priority. 3733 * 3734 * Return: On success, 0 and the RT priority is in @param. Otherwise, an error 3735 * code. 3736 */ 3737SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param) 3738{ 3739 struct sched_param lp = { .sched_priority = 0 }; 3740 struct task_struct *p; 3741 int retval; 3742 3743 if (!param || pid < 0) 3744 return -EINVAL; 3745 3746 rcu_read_lock(); 3747 p = find_process_by_pid(pid); 3748 retval = -ESRCH; 3749 if (!p) 3750 goto out_unlock; 3751 3752 retval = security_task_getscheduler(p); 3753 if (retval) 3754 goto out_unlock; 3755 3756 if (task_has_rt_policy(p)) 3757 lp.sched_priority = p->rt_priority; 3758 rcu_read_unlock(); 3759 3760 /* 3761 * This one might sleep, we cannot do it with a spinlock held ... 3762 */ 3763 retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; 3764 3765 return retval; 3766 3767out_unlock: 3768 rcu_read_unlock(); 3769 return retval; 3770} 3771 3772static int sched_read_attr(struct sched_attr __user *uattr, 3773 struct sched_attr *attr, 3774 unsigned int usize) 3775{ 3776 int ret; 3777 3778 if (!access_ok(VERIFY_WRITE, uattr, usize)) 3779 return -EFAULT; 3780 3781 /* 3782 * If we're handed a smaller struct than we know of, 3783 * ensure all the unknown bits are 0 - i.e. old 3784 * user-space does not get uncomplete information. 3785 */ 3786 if (usize < sizeof(*attr)) { 3787 unsigned char *addr; 3788 unsigned char *end; 3789 3790 addr = (void *)attr + usize; 3791 end = (void *)attr + sizeof(*attr); 3792 3793 for (; addr < end; addr++) { 3794 if (*addr) 3795 goto err_size; 3796 } 3797 3798 attr->size = usize; 3799 } 3800 3801 ret = copy_to_user(uattr, attr, attr->size); 3802 if (ret) 3803 return -EFAULT; 3804 3805out: 3806 return ret; 3807 3808err_size: 3809 ret = -E2BIG; 3810 goto out; 3811} 3812 3813/** 3814 * sys_sched_getattr - similar to sched_getparam, but with sched_attr 3815 * @pid: the pid in question. 3816 * @uattr: structure containing the extended parameters. 3817 * @size: sizeof(attr) for fwd/bwd comp. 3818 * @flags: for future extension. 3819 */ 3820SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr, 3821 unsigned int, size, unsigned int, flags) 3822{ 3823 struct sched_attr attr = { 3824 .size = sizeof(struct sched_attr), 3825 }; 3826 struct task_struct *p; 3827 int retval; 3828 3829 if (!uattr || pid < 0 || size > PAGE_SIZE || 3830 size < SCHED_ATTR_SIZE_VER0 || flags) 3831 return -EINVAL; 3832 3833 rcu_read_lock(); 3834 p = find_process_by_pid(pid); 3835 retval = -ESRCH; 3836 if (!p) 3837 goto out_unlock; 3838 3839 retval = security_task_getscheduler(p); 3840 if (retval) 3841 goto out_unlock; 3842 3843 attr.sched_policy = p->policy; 3844 if (p->sched_reset_on_fork) 3845 attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK; 3846 if (task_has_dl_policy(p)) 3847 __getparam_dl(p, &attr); 3848 else if (task_has_rt_policy(p)) 3849 attr.sched_priority = p->rt_priority; 3850 else 3851 attr.sched_nice = task_nice(p); 3852 3853 rcu_read_unlock(); 3854 3855 retval = sched_read_attr(uattr, &attr, size); 3856 return retval; 3857 3858out_unlock: 3859 rcu_read_unlock(); 3860 return retval; 3861} 3862 3863long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) 3864{ 3865 cpumask_var_t cpus_allowed, new_mask; 3866 struct task_struct *p; 3867 int retval; 3868 3869 rcu_read_lock(); 3870 3871 p = find_process_by_pid(pid); 3872 if (!p) { 3873 rcu_read_unlock(); 3874 return -ESRCH; 3875 } 3876 3877 /* Prevent p going away */ 3878 get_task_struct(p); 3879 rcu_read_unlock(); 3880 3881 if (p->flags & PF_NO_SETAFFINITY) { 3882 retval = -EINVAL; 3883 goto out_put_task; 3884 } 3885 if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) { 3886 retval = -ENOMEM; 3887 goto out_put_task; 3888 } 3889 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) { 3890 retval = -ENOMEM; 3891 goto out_free_cpus_allowed; 3892 } 3893 retval = -EPERM; 3894 if (!check_same_owner(p)) { 3895 rcu_read_lock(); 3896 if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) { 3897 rcu_read_unlock(); 3898 goto out_unlock; 3899 } 3900 rcu_read_unlock(); 3901 } 3902 3903 retval = security_task_setscheduler(p); 3904 if (retval) 3905 goto out_unlock; 3906 3907 3908 cpuset_cpus_allowed(p, cpus_allowed); 3909 cpumask_and(new_mask, in_mask, cpus_allowed); 3910 3911 /* 3912 * Since bandwidth control happens on root_domain basis, 3913 * if admission test is enabled, we only admit -deadline 3914 * tasks allowed to run on all the CPUs in the task's 3915 * root_domain. 3916 */ 3917#ifdef CONFIG_SMP 3918 if (task_has_dl_policy(p)) { 3919 const struct cpumask *span = task_rq(p)->rd->span; 3920 3921 if (dl_bandwidth_enabled() && !cpumask_subset(span, new_mask)) { 3922 retval = -EBUSY; 3923 goto out_unlock; 3924 } 3925 } 3926#endif 3927again: 3928 retval = set_cpus_allowed_ptr(p, new_mask); 3929 3930 if (!retval) { 3931 cpuset_cpus_allowed(p, cpus_allowed); 3932 if (!cpumask_subset(new_mask, cpus_allowed)) { 3933 /* 3934 * We must have raced with a concurrent cpuset 3935 * update. Just reset the cpus_allowed to the 3936 * cpuset's cpus_allowed 3937 */ 3938 cpumask_copy(new_mask, cpus_allowed); 3939 goto again; 3940 } 3941 } 3942out_unlock: 3943 free_cpumask_var(new_mask); 3944out_free_cpus_allowed: 3945 free_cpumask_var(cpus_allowed); 3946out_put_task: 3947 put_task_struct(p); 3948 return retval; 3949} 3950 3951static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, 3952 struct cpumask *new_mask) 3953{ 3954 if (len < cpumask_size()) 3955 cpumask_clear(new_mask); 3956 else if (len > cpumask_size()) 3957 len = cpumask_size(); 3958 3959 return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; 3960} 3961 3962/** 3963 * sys_sched_setaffinity - set the cpu affinity of a process 3964 * @pid: pid of the process 3965 * @len: length in bytes of the bitmask pointed to by user_mask_ptr 3966 * @user_mask_ptr: user-space pointer to the new cpu mask 3967 * 3968 * Return: 0 on success. An error code otherwise. 3969 */ 3970SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len, 3971 unsigned long __user *, user_mask_ptr) 3972{ 3973 cpumask_var_t new_mask; 3974 int retval; 3975 3976 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) 3977 return -ENOMEM; 3978 3979 retval = get_user_cpu_mask(user_mask_ptr, len, new_mask); 3980 if (retval == 0) 3981 retval = sched_setaffinity(pid, new_mask); 3982 free_cpumask_var(new_mask); 3983 return retval; 3984} 3985 3986long sched_getaffinity(pid_t pid, struct cpumask *mask) 3987{ 3988 struct task_struct *p; 3989 unsigned long flags; 3990 int retval; 3991 3992 rcu_read_lock(); 3993 3994 retval = -ESRCH; 3995 p = find_process_by_pid(pid); 3996 if (!p) 3997 goto out_unlock; 3998 3999 retval = security_task_getscheduler(p); 4000 if (retval) 4001 goto out_unlock; 4002 4003 raw_spin_lock_irqsave(&p->pi_lock, flags); 4004 cpumask_and(mask, &p->cpus_allowed, cpu_active_mask); 4005 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 4006 4007out_unlock: 4008 rcu_read_unlock(); 4009 4010 return retval; 4011} 4012 4013/** 4014 * sys_sched_getaffinity - get the cpu affinity of a process 4015 * @pid: pid of the process 4016 * @len: length in bytes of the bitmask pointed to by user_mask_ptr 4017 * @user_mask_ptr: user-space pointer to hold the current cpu mask 4018 * 4019 * Return: 0 on success. An error code otherwise. 4020 */ 4021SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len, 4022 unsigned long __user *, user_mask_ptr) 4023{ 4024 int ret; 4025 cpumask_var_t mask; 4026 4027 if ((len * BITS_PER_BYTE) < nr_cpu_ids) 4028 return -EINVAL; 4029 if (len & (sizeof(unsigned long)-1)) 4030 return -EINVAL; 4031 4032 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) 4033 return -ENOMEM; 4034 4035 ret = sched_getaffinity(pid, mask); 4036 if (ret == 0) { 4037 size_t retlen = min_t(size_t, len, cpumask_size()); 4038 4039 if (copy_to_user(user_mask_ptr, mask, retlen)) 4040 ret = -EFAULT; 4041 else 4042 ret = retlen; 4043 } 4044 free_cpumask_var(mask); 4045 4046 return ret; 4047} 4048 4049/** 4050 * sys_sched_yield - yield the current processor to other threads. 4051 * 4052 * This function yields the current CPU to other tasks. If there are no 4053 * other threads running on this CPU then this function will return. 4054 * 4055 * Return: 0. 4056 */ 4057SYSCALL_DEFINE0(sched_yield) 4058{ 4059 struct rq *rq = this_rq_lock(); 4060 4061 schedstat_inc(rq, yld_count); 4062 current->sched_class->yield_task(rq); 4063 4064 /* 4065 * Since we are going to call schedule() anyway, there's 4066 * no need to preempt or enable interrupts: 4067 */ 4068 __release(rq->lock); 4069 spin_release(&rq->lock.dep_map, 1, _THIS_IP_); 4070 do_raw_spin_unlock(&rq->lock); 4071 sched_preempt_enable_no_resched(); 4072 4073 schedule(); 4074 4075 return 0; 4076} 4077 4078static void __cond_resched(void) 4079{ 4080 __preempt_count_add(PREEMPT_ACTIVE); 4081 __schedule(); 4082 __preempt_count_sub(PREEMPT_ACTIVE); 4083} 4084 4085int __sched _cond_resched(void) 4086{ 4087 if (should_resched()) { 4088 __cond_resched(); 4089 return 1; 4090 } 4091 return 0; 4092} 4093EXPORT_SYMBOL(_cond_resched); 4094 4095/* 4096 * __cond_resched_lock() - if a reschedule is pending, drop the given lock, 4097 * call schedule, and on return reacquire the lock. 4098 * 4099 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level 4100 * operations here to prevent schedule() from being called twice (once via 4101 * spin_unlock(), once by hand). 4102 */ 4103int __cond_resched_lock(spinlock_t *lock) 4104{ 4105 int resched = should_resched(); 4106 int ret = 0; 4107 4108 lockdep_assert_held(lock); 4109 4110 if (spin_needbreak(lock) || resched) { 4111 spin_unlock(lock); 4112 if (resched) 4113 __cond_resched(); 4114 else 4115 cpu_relax(); 4116 ret = 1; 4117 spin_lock(lock); 4118 } 4119 return ret; 4120} 4121EXPORT_SYMBOL(__cond_resched_lock); 4122 4123int __sched __cond_resched_softirq(void) 4124{ 4125 BUG_ON(!in_softirq()); 4126 4127 if (should_resched()) { 4128 local_bh_enable(); 4129 __cond_resched(); 4130 local_bh_disable(); 4131 return 1; 4132 } 4133 return 0; 4134} 4135EXPORT_SYMBOL(__cond_resched_softirq); 4136 4137/** 4138 * yield - yield the current processor to other threads. 4139 * 4140 * Do not ever use this function, there's a 99% chance you're doing it wrong. 4141 * 4142 * The scheduler is at all times free to pick the calling task as the most 4143 * eligible task to run, if removing the yield() call from your code breaks 4144 * it, its already broken. 4145 * 4146 * Typical broken usage is: 4147 * 4148 * while (!event) 4149 * yield(); 4150 * 4151 * where one assumes that yield() will let 'the other' process run that will 4152 * make event true. If the current task is a SCHED_FIFO task that will never 4153 * happen. Never use yield() as a progress guarantee!! 4154 * 4155 * If you want to use yield() to wait for something, use wait_event(). 4156 * If you want to use yield() to be 'nice' for others, use cond_resched(). 4157 * If you still want to use yield(), do not! 4158 */ 4159void __sched yield(void) 4160{ 4161 set_current_state(TASK_RUNNING); 4162 sys_sched_yield(); 4163} 4164EXPORT_SYMBOL(yield); 4165 4166/** 4167 * yield_to - yield the current processor to another thread in 4168 * your thread group, or accelerate that thread toward the 4169 * processor it's on. 4170 * @p: target task 4171 * @preempt: whether task preemption is allowed or not 4172 * 4173 * It's the caller's job to ensure that the target task struct 4174 * can't go away on us before we can do any checks. 4175 * 4176 * Return: 4177 * true (>0) if we indeed boosted the target task. 4178 * false (0) if we failed to boost the target. 4179 * -ESRCH if there's no task to yield to. 4180 */ 4181bool __sched yield_to(struct task_struct *p, bool preempt) 4182{ 4183 struct task_struct *curr = current; 4184 struct rq *rq, *p_rq; 4185 unsigned long flags; 4186 int yielded = 0; 4187 4188 local_irq_save(flags); 4189 rq = this_rq(); 4190 4191again: 4192 p_rq = task_rq(p); 4193 /* 4194 * If we're the only runnable task on the rq and target rq also 4195 * has only one task, there's absolutely no point in yielding. 4196 */ 4197 if (rq->nr_running == 1 && p_rq->nr_running == 1) { 4198 yielded = -ESRCH; 4199 goto out_irq; 4200 } 4201 4202 double_rq_lock(rq, p_rq); 4203 if (task_rq(p) != p_rq) { 4204 double_rq_unlock(rq, p_rq); 4205 goto again; 4206 } 4207 4208 if (!curr->sched_class->yield_to_task) 4209 goto out_unlock; 4210 4211 if (curr->sched_class != p->sched_class) 4212 goto out_unlock; 4213 4214 if (task_running(p_rq, p) || p->state) 4215 goto out_unlock; 4216 4217 yielded = curr->sched_class->yield_to_task(rq, p, preempt); 4218 if (yielded) { 4219 schedstat_inc(rq, yld_count); 4220 /* 4221 * Make p's CPU reschedule; pick_next_entity takes care of 4222 * fairness. 4223 */ 4224 if (preempt && rq != p_rq) 4225 resched_task(p_rq->curr); 4226 } 4227 4228out_unlock: 4229 double_rq_unlock(rq, p_rq); 4230out_irq: 4231 local_irq_restore(flags); 4232 4233 if (yielded > 0) 4234 schedule(); 4235 4236 return yielded; 4237} 4238EXPORT_SYMBOL_GPL(yield_to); 4239 4240/* 4241 * This task is about to go to sleep on IO. Increment rq->nr_iowait so 4242 * that process accounting knows that this is a task in IO wait state. 4243 */ 4244void __sched io_schedule(void) 4245{ 4246 struct rq *rq = raw_rq(); 4247 4248 delayacct_blkio_start(); 4249 atomic_inc(&rq->nr_iowait); 4250 blk_flush_plug(current); 4251 current->in_iowait = 1; 4252 schedule(); 4253 current->in_iowait = 0; 4254 atomic_dec(&rq->nr_iowait); 4255 delayacct_blkio_end(); 4256} 4257EXPORT_SYMBOL(io_schedule); 4258 4259long __sched io_schedule_timeout(long timeout) 4260{ 4261 struct rq *rq = raw_rq(); 4262 long ret; 4263 4264 delayacct_blkio_start(); 4265 atomic_inc(&rq->nr_iowait); 4266 blk_flush_plug(current); 4267 current->in_iowait = 1; 4268 ret = schedule_timeout(timeout); 4269 current->in_iowait = 0; 4270 atomic_dec(&rq->nr_iowait); 4271 delayacct_blkio_end(); 4272 return ret; 4273} 4274 4275/** 4276 * sys_sched_get_priority_max - return maximum RT priority. 4277 * @policy: scheduling class. 4278 * 4279 * Return: On success, this syscall returns the maximum 4280 * rt_priority that can be used by a given scheduling class. 4281 * On failure, a negative error code is returned. 4282 */ 4283SYSCALL_DEFINE1(sched_get_priority_max, int, policy) 4284{ 4285 int ret = -EINVAL; 4286 4287 switch (policy) { 4288 case SCHED_FIFO: 4289 case SCHED_RR: 4290 ret = MAX_USER_RT_PRIO-1; 4291 break; 4292 case SCHED_DEADLINE: 4293 case SCHED_NORMAL: 4294 case SCHED_BATCH: 4295 case SCHED_IDLE: 4296 ret = 0; 4297 break; 4298 } 4299 return ret; 4300} 4301 4302/** 4303 * sys_sched_get_priority_min - return minimum RT priority. 4304 * @policy: scheduling class. 4305 * 4306 * Return: On success, this syscall returns the minimum 4307 * rt_priority that can be used by a given scheduling class. 4308 * On failure, a negative error code is returned. 4309 */ 4310SYSCALL_DEFINE1(sched_get_priority_min, int, policy) 4311{ 4312 int ret = -EINVAL; 4313 4314 switch (policy) { 4315 case SCHED_FIFO: 4316 case SCHED_RR: 4317 ret = 1; 4318 break; 4319 case SCHED_DEADLINE: 4320 case SCHED_NORMAL: 4321 case SCHED_BATCH: 4322 case SCHED_IDLE: 4323 ret = 0; 4324 } 4325 return ret; 4326} 4327 4328/** 4329 * sys_sched_rr_get_interval - return the default timeslice of a process. 4330 * @pid: pid of the process. 4331 * @interval: userspace pointer to the timeslice value. 4332 * 4333 * this syscall writes the default timeslice value of a given process 4334 * into the user-space timespec buffer. A value of '0' means infinity. 4335 * 4336 * Return: On success, 0 and the timeslice is in @interval. Otherwise, 4337 * an error code. 4338 */ 4339SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid, 4340 struct timespec __user *, interval) 4341{ 4342 struct task_struct *p; 4343 unsigned int time_slice; 4344 unsigned long flags; 4345 struct rq *rq; 4346 int retval; 4347 struct timespec t; 4348 4349 if (pid < 0) 4350 return -EINVAL; 4351 4352 retval = -ESRCH; 4353 rcu_read_lock(); 4354 p = find_process_by_pid(pid); 4355 if (!p) 4356 goto out_unlock; 4357 4358 retval = security_task_getscheduler(p); 4359 if (retval) 4360 goto out_unlock; 4361 4362 rq = task_rq_lock(p, &flags); 4363 time_slice = 0; 4364 if (p->sched_class->get_rr_interval) 4365 time_slice = p->sched_class->get_rr_interval(rq, p); 4366 task_rq_unlock(rq, p, &flags); 4367 4368 rcu_read_unlock(); 4369 jiffies_to_timespec(time_slice, &t); 4370 retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; 4371 return retval; 4372 4373out_unlock: 4374 rcu_read_unlock(); 4375 return retval; 4376} 4377 4378static const char stat_nam[] = TASK_STATE_TO_CHAR_STR; 4379 4380void sched_show_task(struct task_struct *p) 4381{ 4382 unsigned long free = 0; 4383 int ppid; 4384 unsigned state; 4385 4386 state = p->state ? __ffs(p->state) + 1 : 0; 4387 printk(KERN_INFO "%-15.15s %c", p->comm, 4388 state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); 4389#if BITS_PER_LONG == 32 4390 if (state == TASK_RUNNING) 4391 printk(KERN_CONT " running "); 4392 else 4393 printk(KERN_CONT " %08lx ", thread_saved_pc(p)); 4394#else 4395 if (state == TASK_RUNNING) 4396 printk(KERN_CONT " running task "); 4397 else 4398 printk(KERN_CONT " %016lx ", thread_saved_pc(p)); 4399#endif 4400#ifdef CONFIG_DEBUG_STACK_USAGE 4401 free = stack_not_used(p); 4402#endif 4403 rcu_read_lock(); 4404 ppid = task_pid_nr(rcu_dereference(p->real_parent)); 4405 rcu_read_unlock(); 4406 printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free, 4407 task_pid_nr(p), ppid, 4408 (unsigned long)task_thread_info(p)->flags); 4409 4410 print_worker_info(KERN_INFO, p); 4411 show_stack(p, NULL); 4412} 4413 4414void show_state_filter(unsigned long state_filter) 4415{ 4416 struct task_struct *g, *p; 4417 4418#if BITS_PER_LONG == 32 4419 printk(KERN_INFO 4420 " task PC stack pid father\n"); 4421#else 4422 printk(KERN_INFO 4423 " task PC stack pid father\n"); 4424#endif 4425 rcu_read_lock(); 4426 do_each_thread(g, p) { 4427 /* 4428 * reset the NMI-timeout, listing all files on a slow 4429 * console might take a lot of time: 4430 */ 4431 touch_nmi_watchdog(); 4432 if (!state_filter || (p->state & state_filter)) 4433 sched_show_task(p); 4434 } while_each_thread(g, p); 4435 4436 touch_all_softlockup_watchdogs(); 4437 4438#ifdef CONFIG_SCHED_DEBUG 4439 sysrq_sched_debug_show(); 4440#endif 4441 rcu_read_unlock(); 4442 /* 4443 * Only show locks if all tasks are dumped: 4444 */ 4445 if (!state_filter) 4446 debug_show_all_locks(); 4447} 4448 4449void init_idle_bootup_task(struct task_struct *idle) 4450{ 4451 idle->sched_class = &idle_sched_class; 4452} 4453 4454/** 4455 * init_idle - set up an idle thread for a given CPU 4456 * @idle: task in question 4457 * @cpu: cpu the idle task belongs to 4458 * 4459 * NOTE: this function does not set the idle thread's NEED_RESCHED 4460 * flag, to make booting more robust. 4461 */ 4462void init_idle(struct task_struct *idle, int cpu) 4463{ 4464 struct rq *rq = cpu_rq(cpu); 4465 unsigned long flags; 4466 4467 raw_spin_lock_irqsave(&rq->lock, flags); 4468 4469 __sched_fork(0, idle); 4470 idle->state = TASK_RUNNING; 4471 idle->se.exec_start = sched_clock(); 4472 4473 do_set_cpus_allowed(idle, cpumask_of(cpu)); 4474 /* 4475 * We're having a chicken and egg problem, even though we are 4476 * holding rq->lock, the cpu isn't yet set to this cpu so the 4477 * lockdep check in task_group() will fail. 4478 * 4479 * Similar case to sched_fork(). / Alternatively we could 4480 * use task_rq_lock() here and obtain the other rq->lock. 4481 * 4482 * Silence PROVE_RCU 4483 */ 4484 rcu_read_lock(); 4485 __set_task_cpu(idle, cpu); 4486 rcu_read_unlock(); 4487 4488 rq->curr = rq->idle = idle; 4489 idle->on_rq = 1; 4490#if defined(CONFIG_SMP) 4491 idle->on_cpu = 1; 4492#endif 4493 raw_spin_unlock_irqrestore(&rq->lock, flags); 4494 4495 /* Set the preempt count _outside_ the spinlocks! */ 4496 init_idle_preempt_count(idle, cpu); 4497 4498 /* 4499 * The idle tasks have their own, simple scheduling class: 4500 */ 4501 idle->sched_class = &idle_sched_class; 4502 ftrace_graph_init_idle_task(idle, cpu); 4503 vtime_init_idle(idle, cpu); 4504#if defined(CONFIG_SMP) 4505 sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu); 4506#endif 4507} 4508 4509#ifdef CONFIG_SMP 4510void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) 4511{ 4512 if (p->sched_class && p->sched_class->set_cpus_allowed) 4513 p->sched_class->set_cpus_allowed(p, new_mask); 4514 4515 cpumask_copy(&p->cpus_allowed, new_mask); 4516 p->nr_cpus_allowed = cpumask_weight(new_mask); 4517} 4518 4519/* 4520 * This is how migration works: 4521 * 4522 * 1) we invoke migration_cpu_stop() on the target CPU using 4523 * stop_one_cpu(). 4524 * 2) stopper starts to run (implicitly forcing the migrated thread 4525 * off the CPU) 4526 * 3) it checks whether the migrated task is still in the wrong runqueue. 4527 * 4) if it's in the wrong runqueue then the migration thread removes 4528 * it and puts it into the right queue. 4529 * 5) stopper completes and stop_one_cpu() returns and the migration 4530 * is done. 4531 */ 4532 4533/* 4534 * Change a given task's CPU affinity. Migrate the thread to a 4535 * proper CPU and schedule it away if the CPU it's executing on 4536 * is removed from the allowed bitmask. 4537 * 4538 * NOTE: the caller must have a valid reference to the task, the 4539 * task must not exit() & deallocate itself prematurely. The 4540 * call is not atomic; no spinlocks may be held. 4541 */ 4542int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) 4543{ 4544 unsigned long flags; 4545 struct rq *rq; 4546 unsigned int dest_cpu; 4547 int ret = 0; 4548 4549 rq = task_rq_lock(p, &flags); 4550 4551 if (cpumask_equal(&p->cpus_allowed, new_mask)) 4552 goto out; 4553 4554 if (!cpumask_intersects(new_mask, cpu_active_mask)) { 4555 ret = -EINVAL; 4556 goto out; 4557 } 4558 4559 do_set_cpus_allowed(p, new_mask); 4560 4561 /* Can the task run on the task's current CPU? If so, we're done */ 4562 if (cpumask_test_cpu(task_cpu(p), new_mask)) 4563 goto out; 4564 4565 dest_cpu = cpumask_any_and(cpu_active_mask, new_mask); 4566 if (p->on_rq) { 4567 struct migration_arg arg = { p, dest_cpu }; 4568 /* Need help from migration thread: drop lock and wait. */ 4569 task_rq_unlock(rq, p, &flags); 4570 stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg); 4571 tlb_migrate_finish(p->mm); 4572 return 0; 4573 } 4574out: 4575 task_rq_unlock(rq, p, &flags); 4576 4577 return ret; 4578} 4579EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr); 4580 4581/* 4582 * Move (not current) task off this cpu, onto dest cpu. We're doing 4583 * this because either it can't run here any more (set_cpus_allowed() 4584 * away from this CPU, or CPU going down), or because we're 4585 * attempting to rebalance this task on exec (sched_exec). 4586 * 4587 * So we race with normal scheduler movements, but that's OK, as long 4588 * as the task is no longer on this CPU. 4589 * 4590 * Returns non-zero if task was successfully migrated. 4591 */ 4592static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) 4593{ 4594 struct rq *rq_dest, *rq_src; 4595 int ret = 0; 4596 4597 if (unlikely(!cpu_active(dest_cpu))) 4598 return ret; 4599 4600 rq_src = cpu_rq(src_cpu); 4601 rq_dest = cpu_rq(dest_cpu); 4602 4603 raw_spin_lock(&p->pi_lock); 4604 double_rq_lock(rq_src, rq_dest); 4605 /* Already moved. */ 4606 if (task_cpu(p) != src_cpu) 4607 goto done; 4608 /* Affinity changed (again). */ 4609 if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) 4610 goto fail; 4611 4612 /* 4613 * If we're not on a rq, the next wake-up will ensure we're 4614 * placed properly. 4615 */ 4616 if (p->on_rq) { 4617 dequeue_task(rq_src, p, 0); 4618 set_task_cpu(p, dest_cpu); 4619 enqueue_task(rq_dest, p, 0); 4620 check_preempt_curr(rq_dest, p, 0); 4621 } 4622done: 4623 ret = 1; 4624fail: 4625 double_rq_unlock(rq_src, rq_dest); 4626 raw_spin_unlock(&p->pi_lock); 4627 return ret; 4628} 4629 4630#ifdef CONFIG_NUMA_BALANCING 4631/* Migrate current task p to target_cpu */ 4632int migrate_task_to(struct task_struct *p, int target_cpu) 4633{ 4634 struct migration_arg arg = { p, target_cpu }; 4635 int curr_cpu = task_cpu(p); 4636 4637 if (curr_cpu == target_cpu) 4638 return 0; 4639 4640 if (!cpumask_test_cpu(target_cpu, tsk_cpus_allowed(p))) 4641 return -EINVAL; 4642 4643 /* TODO: This is not properly updating schedstats */ 4644 4645 trace_sched_move_numa(p, curr_cpu, target_cpu); 4646 return stop_one_cpu(curr_cpu, migration_cpu_stop, &arg); 4647} 4648 4649/* 4650 * Requeue a task on a given node and accurately track the number of NUMA 4651 * tasks on the runqueues 4652 */ 4653void sched_setnuma(struct task_struct *p, int nid) 4654{ 4655 struct rq *rq; 4656 unsigned long flags; 4657 bool on_rq, running; 4658 4659 rq = task_rq_lock(p, &flags); 4660 on_rq = p->on_rq; 4661 running = task_current(rq, p); 4662 4663 if (on_rq) 4664 dequeue_task(rq, p, 0); 4665 if (running) 4666 p->sched_class->put_prev_task(rq, p); 4667 4668 p->numa_preferred_nid = nid; 4669 4670 if (running) 4671 p->sched_class->set_curr_task(rq); 4672 if (on_rq) 4673 enqueue_task(rq, p, 0); 4674 task_rq_unlock(rq, p, &flags); 4675} 4676#endif 4677 4678/* 4679 * migration_cpu_stop - this will be executed by a highprio stopper thread 4680 * and performs thread migration by bumping thread off CPU then 4681 * 'pushing' onto another runqueue. 4682 */ 4683static int migration_cpu_stop(void *data) 4684{ 4685 struct migration_arg *arg = data; 4686 4687 /* 4688 * The original target cpu might have gone down and we might 4689 * be on another cpu but it doesn't matter. 4690 */ 4691 local_irq_disable(); 4692 __migrate_task(arg->task, raw_smp_processor_id(), arg->dest_cpu); 4693 local_irq_enable(); 4694 return 0; 4695} 4696 4697#ifdef CONFIG_HOTPLUG_CPU 4698 4699/* 4700 * Ensures that the idle task is using init_mm right before its cpu goes 4701 * offline. 4702 */ 4703void idle_task_exit(void) 4704{ 4705 struct mm_struct *mm = current->active_mm; 4706 4707 BUG_ON(cpu_online(smp_processor_id())); 4708 4709 if (mm != &init_mm) { 4710 switch_mm(mm, &init_mm, current); 4711 finish_arch_post_lock_switch(); 4712 } 4713 mmdrop(mm); 4714} 4715 4716/* 4717 * Since this CPU is going 'away' for a while, fold any nr_active delta 4718 * we might have. Assumes we're called after migrate_tasks() so that the 4719 * nr_active count is stable. 4720 * 4721 * Also see the comment "Global load-average calculations". 4722 */ 4723static void calc_load_migrate(struct rq *rq) 4724{ 4725 long delta = calc_load_fold_active(rq); 4726 if (delta) 4727 atomic_long_add(delta, &calc_load_tasks); 4728} 4729 4730static void put_prev_task_fake(struct rq *rq, struct task_struct *prev) 4731{ 4732} 4733 4734static const struct sched_class fake_sched_class = { 4735 .put_prev_task = put_prev_task_fake, 4736}; 4737 4738static struct task_struct fake_task = { 4739 /* 4740 * Avoid pull_{rt,dl}_task() 4741 */ 4742 .prio = MAX_PRIO + 1, 4743 .sched_class = &fake_sched_class, 4744}; 4745 4746/* 4747 * Migrate all tasks from the rq, sleeping tasks will be migrated by 4748 * try_to_wake_up()->select_task_rq(). 4749 * 4750 * Called with rq->lock held even though we'er in stop_machine() and 4751 * there's no concurrency possible, we hold the required locks anyway 4752 * because of lock validation efforts. 4753 */ 4754static void migrate_tasks(unsigned int dead_cpu) 4755{ 4756 struct rq *rq = cpu_rq(dead_cpu); 4757 struct task_struct *next, *stop = rq->stop; 4758 int dest_cpu; 4759 4760 /* 4761 * Fudge the rq selection such that the below task selection loop 4762 * doesn't get stuck on the currently eligible stop task. 4763 * 4764 * We're currently inside stop_machine() and the rq is either stuck 4765 * in the stop_machine_cpu_stop() loop, or we're executing this code, 4766 * either way we should never end up calling schedule() until we're 4767 * done here. 4768 */ 4769 rq->stop = NULL; 4770 4771 /* 4772 * put_prev_task() and pick_next_task() sched 4773 * class method both need to have an up-to-date 4774 * value of rq->clock[_task] 4775 */ 4776 update_rq_clock(rq); 4777 4778 for ( ; ; ) { 4779 /* 4780 * There's this thread running, bail when that's the only 4781 * remaining thread. 4782 */ 4783 if (rq->nr_running == 1) 4784 break; 4785 4786 next = pick_next_task(rq, &fake_task); 4787 BUG_ON(!next); 4788 next->sched_class->put_prev_task(rq, next); 4789 4790 /* Find suitable destination for @next, with force if needed. */ 4791 dest_cpu = select_fallback_rq(dead_cpu, next); 4792 raw_spin_unlock(&rq->lock); 4793 4794 __migrate_task(next, dead_cpu, dest_cpu); 4795 4796 raw_spin_lock(&rq->lock); 4797 } 4798 4799 rq->stop = stop; 4800} 4801 4802#endif /* CONFIG_HOTPLUG_CPU */ 4803 4804#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL) 4805 4806static struct ctl_table sd_ctl_dir[] = { 4807 { 4808 .procname = "sched_domain", 4809 .mode = 0555, 4810 }, 4811 {} 4812}; 4813 4814static struct ctl_table sd_ctl_root[] = { 4815 { 4816 .procname = "kernel", 4817 .mode = 0555, 4818 .child = sd_ctl_dir, 4819 }, 4820 {} 4821}; 4822 4823static struct ctl_table *sd_alloc_ctl_entry(int n) 4824{ 4825 struct ctl_table *entry = 4826 kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL); 4827 4828 return entry; 4829} 4830 4831static void sd_free_ctl_entry(struct ctl_table **tablep) 4832{ 4833 struct ctl_table *entry; 4834 4835 /* 4836 * In the intermediate directories, both the child directory and 4837 * procname are dynamically allocated and could fail but the mode 4838 * will always be set. In the lowest directory the names are 4839 * static strings and all have proc handlers. 4840 */ 4841 for (entry = *tablep; entry->mode; entry++) { 4842 if (entry->child) 4843 sd_free_ctl_entry(&entry->child); 4844 if (entry->proc_handler == NULL) 4845 kfree(entry->procname); 4846 } 4847 4848 kfree(*tablep); 4849 *tablep = NULL; 4850} 4851 4852static int min_load_idx = 0; 4853static int max_load_idx = CPU_LOAD_IDX_MAX-1; 4854 4855static void 4856set_table_entry(struct ctl_table *entry, 4857 const char *procname, void *data, int maxlen, 4858 umode_t mode, proc_handler *proc_handler, 4859 bool load_idx) 4860{ 4861 entry->procname = procname; 4862 entry->data = data; 4863 entry->maxlen = maxlen; 4864 entry->mode = mode; 4865 entry->proc_handler = proc_handler; 4866 4867 if (load_idx) { 4868 entry->extra1 = &min_load_idx; 4869 entry->extra2 = &max_load_idx; 4870 } 4871} 4872 4873static struct ctl_table * 4874sd_alloc_ctl_domain_table(struct sched_domain *sd) 4875{ 4876 struct ctl_table *table = sd_alloc_ctl_entry(14); 4877 4878 if (table == NULL) 4879 return NULL; 4880 4881 set_table_entry(&table[0], "min_interval", &sd->min_interval, 4882 sizeof(long), 0644, proc_doulongvec_minmax, false); 4883 set_table_entry(&table[1], "max_interval", &sd->max_interval, 4884 sizeof(long), 0644, proc_doulongvec_minmax, false); 4885 set_table_entry(&table[2], "busy_idx", &sd->busy_idx, 4886 sizeof(int), 0644, proc_dointvec_minmax, true); 4887 set_table_entry(&table[3], "idle_idx", &sd->idle_idx, 4888 sizeof(int), 0644, proc_dointvec_minmax, true); 4889 set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx, 4890 sizeof(int), 0644, proc_dointvec_minmax, true); 4891 set_table_entry(&table[5], "wake_idx", &sd->wake_idx, 4892 sizeof(int), 0644, proc_dointvec_minmax, true); 4893 set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx, 4894 sizeof(int), 0644, proc_dointvec_minmax, true); 4895 set_table_entry(&table[7], "busy_factor", &sd->busy_factor, 4896 sizeof(int), 0644, proc_dointvec_minmax, false); 4897 set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct, 4898 sizeof(int), 0644, proc_dointvec_minmax, false); 4899 set_table_entry(&table[9], "cache_nice_tries", 4900 &sd->cache_nice_tries, 4901 sizeof(int), 0644, proc_dointvec_minmax, false); 4902 set_table_entry(&table[10], "flags", &sd->flags, 4903 sizeof(int), 0644, proc_dointvec_minmax, false); 4904 set_table_entry(&table[11], "max_newidle_lb_cost", 4905 &sd->max_newidle_lb_cost, 4906 sizeof(long), 0644, proc_doulongvec_minmax, false); 4907 set_table_entry(&table[12], "name", sd->name, 4908 CORENAME_MAX_SIZE, 0444, proc_dostring, false); 4909 /* &table[13] is terminator */ 4910 4911 return table; 4912} 4913 4914static struct ctl_table *sd_alloc_ctl_cpu_table(int cpu) 4915{ 4916 struct ctl_table *entry, *table; 4917 struct sched_domain *sd; 4918 int domain_num = 0, i; 4919 char buf[32]; 4920 4921 for_each_domain(cpu, sd) 4922 domain_num++; 4923 entry = table = sd_alloc_ctl_entry(domain_num + 1); 4924 if (table == NULL) 4925 return NULL; 4926 4927 i = 0; 4928 for_each_domain(cpu, sd) { 4929 snprintf(buf, 32, "domain%d", i); 4930 entry->procname = kstrdup(buf, GFP_KERNEL); 4931 entry->mode = 0555; 4932 entry->child = sd_alloc_ctl_domain_table(sd); 4933 entry++; 4934 i++; 4935 } 4936 return table; 4937} 4938 4939static struct ctl_table_header *sd_sysctl_header; 4940static void register_sched_domain_sysctl(void) 4941{ 4942 int i, cpu_num = num_possible_cpus(); 4943 struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1); 4944 char buf[32]; 4945 4946 WARN_ON(sd_ctl_dir[0].child); 4947 sd_ctl_dir[0].child = entry; 4948 4949 if (entry == NULL) 4950 return; 4951 4952 for_each_possible_cpu(i) { 4953 snprintf(buf, 32, "cpu%d", i); 4954 entry->procname = kstrdup(buf, GFP_KERNEL); 4955 entry->mode = 0555; 4956 entry->child = sd_alloc_ctl_cpu_table(i); 4957 entry++; 4958 } 4959 4960 WARN_ON(sd_sysctl_header); 4961 sd_sysctl_header = register_sysctl_table(sd_ctl_root); 4962} 4963 4964/* may be called multiple times per register */ 4965static void unregister_sched_domain_sysctl(void) 4966{ 4967 if (sd_sysctl_header) 4968 unregister_sysctl_table(sd_sysctl_header); 4969 sd_sysctl_header = NULL; 4970 if (sd_ctl_dir[0].child) 4971 sd_free_ctl_entry(&sd_ctl_dir[0].child); 4972} 4973#else 4974static void register_sched_domain_sysctl(void) 4975{ 4976} 4977static void unregister_sched_domain_sysctl(void) 4978{ 4979} 4980#endif 4981 4982static void set_rq_online(struct rq *rq) 4983{ 4984 if (!rq->online) { 4985 const struct sched_class *class; 4986 4987 cpumask_set_cpu(rq->cpu, rq->rd->online); 4988 rq->online = 1; 4989 4990 for_each_class(class) { 4991 if (class->rq_online) 4992 class->rq_online(rq); 4993 } 4994 } 4995} 4996 4997static void set_rq_offline(struct rq *rq) 4998{ 4999 if (rq->online) { 5000 const struct sched_class *class; 5001 5002 for_each_class(class) { 5003 if (class->rq_offline) 5004 class->rq_offline(rq); 5005 } 5006 5007 cpumask_clear_cpu(rq->cpu, rq->rd->online); 5008 rq->online = 0; 5009 } 5010} 5011 5012/* 5013 * migration_call - callback that gets triggered when a CPU is added. 5014 * Here we can start up the necessary migration thread for the new CPU. 5015 */ 5016static int 5017migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) 5018{ 5019 int cpu = (long)hcpu; 5020 unsigned long flags; 5021 struct rq *rq = cpu_rq(cpu); 5022 5023 switch (action & ~CPU_TASKS_FROZEN) { 5024 5025 case CPU_UP_PREPARE: 5026 rq->calc_load_update = calc_load_update; 5027 break; 5028 5029 case CPU_ONLINE: 5030 /* Update our root-domain */ 5031 raw_spin_lock_irqsave(&rq->lock, flags); 5032 if (rq->rd) { 5033 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); 5034 5035 set_rq_online(rq); 5036 } 5037 raw_spin_unlock_irqrestore(&rq->lock, flags); 5038 break; 5039 5040#ifdef CONFIG_HOTPLUG_CPU 5041 case CPU_DYING: 5042 sched_ttwu_pending(); 5043 /* Update our root-domain */ 5044 raw_spin_lock_irqsave(&rq->lock, flags); 5045 if (rq->rd) { 5046 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); 5047 set_rq_offline(rq); 5048 } 5049 migrate_tasks(cpu); 5050 BUG_ON(rq->nr_running != 1); /* the migration thread */ 5051 raw_spin_unlock_irqrestore(&rq->lock, flags); 5052 break; 5053 5054 case CPU_DEAD: 5055 calc_load_migrate(rq); 5056 break; 5057#endif 5058 } 5059 5060 update_max_interval(); 5061 5062 return NOTIFY_OK; 5063} 5064 5065/* 5066 * Register at high priority so that task migration (migrate_all_tasks) 5067 * happens before everything else. This has to be lower priority than 5068 * the notifier in the perf_event subsystem, though. 5069 */ 5070static struct notifier_block migration_notifier = { 5071 .notifier_call = migration_call, 5072 .priority = CPU_PRI_MIGRATION, 5073}; 5074 5075static int sched_cpu_active(struct notifier_block *nfb, 5076 unsigned long action, void *hcpu) 5077{ 5078 switch (action & ~CPU_TASKS_FROZEN) { 5079 case CPU_STARTING: 5080 case CPU_DOWN_FAILED: 5081 set_cpu_active((long)hcpu, true); 5082 return NOTIFY_OK; 5083 default: 5084 return NOTIFY_DONE; 5085 } 5086} 5087 5088static int sched_cpu_inactive(struct notifier_block *nfb, 5089 unsigned long action, void *hcpu) 5090{ 5091 unsigned long flags; 5092 long cpu = (long)hcpu; 5093 5094 switch (action & ~CPU_TASKS_FROZEN) { 5095 case CPU_DOWN_PREPARE: 5096 set_cpu_active(cpu, false); 5097 5098 /* explicitly allow suspend */ 5099 if (!(action & CPU_TASKS_FROZEN)) { 5100 struct dl_bw *dl_b = dl_bw_of(cpu); 5101 bool overflow; 5102 int cpus; 5103 5104 raw_spin_lock_irqsave(&dl_b->lock, flags); 5105 cpus = dl_bw_cpus(cpu); 5106 overflow = __dl_overflow(dl_b, cpus, 0, 0); 5107 raw_spin_unlock_irqrestore(&dl_b->lock, flags); 5108 5109 if (overflow) 5110 return notifier_from_errno(-EBUSY); 5111 } 5112 return NOTIFY_OK; 5113 } 5114 5115 return NOTIFY_DONE; 5116} 5117 5118static int __init migration_init(void) 5119{ 5120 void *cpu = (void *)(long)smp_processor_id(); 5121 int err; 5122 5123 /* Initialize migration for the boot CPU */ 5124 err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); 5125 BUG_ON(err == NOTIFY_BAD); 5126 migration_call(&migration_notifier, CPU_ONLINE, cpu); 5127 register_cpu_notifier(&migration_notifier); 5128 5129 /* Register cpu active notifiers */ 5130 cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE); 5131 cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE); 5132 5133 return 0; 5134} 5135early_initcall(migration_init); 5136#endif 5137 5138#ifdef CONFIG_SMP 5139 5140static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */ 5141 5142#ifdef CONFIG_SCHED_DEBUG 5143 5144static __read_mostly int sched_debug_enabled; 5145 5146static int __init sched_debug_setup(char *str) 5147{ 5148 sched_debug_enabled = 1; 5149 5150 return 0; 5151} 5152early_param("sched_debug", sched_debug_setup); 5153 5154static inline bool sched_debug(void) 5155{ 5156 return sched_debug_enabled; 5157} 5158 5159static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, 5160 struct cpumask *groupmask) 5161{ 5162 struct sched_group *group = sd->groups; 5163 char str[256]; 5164 5165 cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd)); 5166 cpumask_clear(groupmask); 5167 5168 printk(KERN_DEBUG "%*s domain %d: ", level, "", level); 5169 5170 if (!(sd->flags & SD_LOAD_BALANCE)) { 5171 printk("does not load-balance\n"); 5172 if (sd->parent) 5173 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain" 5174 " has parent"); 5175 return -1; 5176 } 5177 5178 printk(KERN_CONT "span %s level %s\n", str, sd->name); 5179 5180 if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) { 5181 printk(KERN_ERR "ERROR: domain->span does not contain " 5182 "CPU%d\n", cpu); 5183 } 5184 if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) { 5185 printk(KERN_ERR "ERROR: domain->groups does not contain" 5186 " CPU%d\n", cpu); 5187 } 5188 5189 printk(KERN_DEBUG "%*s groups:", level + 1, ""); 5190 do { 5191 if (!group) { 5192 printk("\n"); 5193 printk(KERN_ERR "ERROR: group is NULL\n"); 5194 break; 5195 } 5196 5197 /* 5198 * Even though we initialize ->power to something semi-sane, 5199 * we leave power_orig unset. This allows us to detect if 5200 * domain iteration is still funny without causing /0 traps. 5201 */ 5202 if (!group->sgp->power_orig) { 5203 printk(KERN_CONT "\n"); 5204 printk(KERN_ERR "ERROR: domain->cpu_power not " 5205 "set\n"); 5206 break; 5207 } 5208 5209 if (!cpumask_weight(sched_group_cpus(group))) { 5210 printk(KERN_CONT "\n"); 5211 printk(KERN_ERR "ERROR: empty group\n"); 5212 break; 5213 } 5214 5215 if (!(sd->flags & SD_OVERLAP) && 5216 cpumask_intersects(groupmask, sched_group_cpus(group))) { 5217 printk(KERN_CONT "\n"); 5218 printk(KERN_ERR "ERROR: repeated CPUs\n"); 5219 break; 5220 } 5221 5222 cpumask_or(groupmask, groupmask, sched_group_cpus(group)); 5223 5224 cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group)); 5225 5226 printk(KERN_CONT " %s", str); 5227 if (group->sgp->power != SCHED_POWER_SCALE) { 5228 printk(KERN_CONT " (cpu_power = %d)", 5229 group->sgp->power); 5230 } 5231 5232 group = group->next; 5233 } while (group != sd->groups); 5234 printk(KERN_CONT "\n"); 5235 5236 if (!cpumask_equal(sched_domain_span(sd), groupmask)) 5237 printk(KERN_ERR "ERROR: groups don't span domain->span\n"); 5238 5239 if (sd->parent && 5240 !cpumask_subset(groupmask, sched_domain_span(sd->parent))) 5241 printk(KERN_ERR "ERROR: parent span is not a superset " 5242 "of domain->span\n"); 5243 return 0; 5244} 5245 5246static void sched_domain_debug(struct sched_domain *sd, int cpu) 5247{ 5248 int level = 0; 5249 5250 if (!sched_debug_enabled) 5251 return; 5252 5253 if (!sd) { 5254 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); 5255 return; 5256 } 5257 5258 printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); 5259 5260 for (;;) { 5261 if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask)) 5262 break; 5263 level++; 5264 sd = sd->parent; 5265 if (!sd) 5266 break; 5267 } 5268} 5269#else /* !CONFIG_SCHED_DEBUG */ 5270# define sched_domain_debug(sd, cpu) do { } while (0) 5271static inline bool sched_debug(void) 5272{ 5273 return false; 5274} 5275#endif /* CONFIG_SCHED_DEBUG */ 5276 5277static int sd_degenerate(struct sched_domain *sd) 5278{ 5279 if (cpumask_weight(sched_domain_span(sd)) == 1) 5280 return 1; 5281 5282 /* Following flags need at least 2 groups */ 5283 if (sd->flags & (SD_LOAD_BALANCE | 5284 SD_BALANCE_NEWIDLE | 5285 SD_BALANCE_FORK | 5286 SD_BALANCE_EXEC | 5287 SD_SHARE_CPUPOWER | 5288 SD_SHARE_PKG_RESOURCES)) { 5289 if (sd->groups != sd->groups->next) 5290 return 0; 5291 } 5292 5293 /* Following flags don't use groups */ 5294 if (sd->flags & (SD_WAKE_AFFINE)) 5295 return 0; 5296 5297 return 1; 5298} 5299 5300static int 5301sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) 5302{ 5303 unsigned long cflags = sd->flags, pflags = parent->flags; 5304 5305 if (sd_degenerate(parent)) 5306 return 1; 5307 5308 if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent))) 5309 return 0; 5310 5311 /* Flags needing groups don't count if only 1 group in parent */ 5312 if (parent->groups == parent->groups->next) { 5313 pflags &= ~(SD_LOAD_BALANCE | 5314 SD_BALANCE_NEWIDLE | 5315 SD_BALANCE_FORK | 5316 SD_BALANCE_EXEC | 5317 SD_SHARE_CPUPOWER | 5318 SD_SHARE_PKG_RESOURCES | 5319 SD_PREFER_SIBLING); 5320 if (nr_node_ids == 1) 5321 pflags &= ~SD_SERIALIZE; 5322 } 5323 if (~cflags & pflags) 5324 return 0; 5325 5326 return 1; 5327} 5328 5329static void free_rootdomain(struct rcu_head *rcu) 5330{ 5331 struct root_domain *rd = container_of(rcu, struct root_domain, rcu); 5332 5333 cpupri_cleanup(&rd->cpupri); 5334 cpudl_cleanup(&rd->cpudl); 5335 free_cpumask_var(rd->dlo_mask); 5336 free_cpumask_var(rd->rto_mask); 5337 free_cpumask_var(rd->online); 5338 free_cpumask_var(rd->span); 5339 kfree(rd); 5340} 5341 5342static void rq_attach_root(struct rq *rq, struct root_domain *rd) 5343{ 5344 struct root_domain *old_rd = NULL; 5345 unsigned long flags; 5346 5347 raw_spin_lock_irqsave(&rq->lock, flags); 5348 5349 if (rq->rd) { 5350 old_rd = rq->rd; 5351 5352 if (cpumask_test_cpu(rq->cpu, old_rd->online)) 5353 set_rq_offline(rq); 5354 5355 cpumask_clear_cpu(rq->cpu, old_rd->span); 5356 5357 /* 5358 * If we dont want to free the old_rd yet then 5359 * set old_rd to NULL to skip the freeing later 5360 * in this function: 5361 */ 5362 if (!atomic_dec_and_test(&old_rd->refcount)) 5363 old_rd = NULL; 5364 } 5365 5366 atomic_inc(&rd->refcount); 5367 rq->rd = rd; 5368 5369 cpumask_set_cpu(rq->cpu, rd->span); 5370 if (cpumask_test_cpu(rq->cpu, cpu_active_mask)) 5371 set_rq_online(rq); 5372 5373 raw_spin_unlock_irqrestore(&rq->lock, flags); 5374 5375 if (old_rd) 5376 call_rcu_sched(&old_rd->rcu, free_rootdomain); 5377} 5378 5379static int init_rootdomain(struct root_domain *rd) 5380{ 5381 memset(rd, 0, sizeof(*rd)); 5382 5383 if (!alloc_cpumask_var(&rd->span, GFP_KERNEL)) 5384 goto out; 5385 if (!alloc_cpumask_var(&rd->online, GFP_KERNEL)) 5386 goto free_span; 5387 if (!alloc_cpumask_var(&rd->dlo_mask, GFP_KERNEL)) 5388 goto free_online; 5389 if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL)) 5390 goto free_dlo_mask; 5391 5392 init_dl_bw(&rd->dl_bw); 5393 if (cpudl_init(&rd->cpudl) != 0) 5394 goto free_dlo_mask; 5395 5396 if (cpupri_init(&rd->cpupri) != 0) 5397 goto free_rto_mask; 5398 return 0; 5399 5400free_rto_mask: 5401 free_cpumask_var(rd->rto_mask); 5402free_dlo_mask: 5403 free_cpumask_var(rd->dlo_mask); 5404free_online: 5405 free_cpumask_var(rd->online); 5406free_span: 5407 free_cpumask_var(rd->span); 5408out: 5409 return -ENOMEM; 5410} 5411 5412/* 5413 * By default the system creates a single root-domain with all cpus as 5414 * members (mimicking the global state we have today). 5415 */ 5416struct root_domain def_root_domain; 5417 5418static void init_defrootdomain(void) 5419{ 5420 init_rootdomain(&def_root_domain); 5421 5422 atomic_set(&def_root_domain.refcount, 1); 5423} 5424 5425static struct root_domain *alloc_rootdomain(void) 5426{ 5427 struct root_domain *rd; 5428 5429 rd = kmalloc(sizeof(*rd), GFP_KERNEL); 5430 if (!rd) 5431 return NULL; 5432 5433 if (init_rootdomain(rd) != 0) { 5434 kfree(rd); 5435 return NULL; 5436 } 5437 5438 return rd; 5439} 5440 5441static void free_sched_groups(struct sched_group *sg, int free_sgp) 5442{ 5443 struct sched_group *tmp, *first; 5444 5445 if (!sg) 5446 return; 5447 5448 first = sg; 5449 do { 5450 tmp = sg->next; 5451 5452 if (free_sgp && atomic_dec_and_test(&sg->sgp->ref)) 5453 kfree(sg->sgp); 5454 5455 kfree(sg); 5456 sg = tmp; 5457 } while (sg != first); 5458} 5459 5460static void free_sched_domain(struct rcu_head *rcu) 5461{ 5462 struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu); 5463 5464 /* 5465 * If its an overlapping domain it has private groups, iterate and 5466 * nuke them all. 5467 */ 5468 if (sd->flags & SD_OVERLAP) { 5469 free_sched_groups(sd->groups, 1); 5470 } else if (atomic_dec_and_test(&sd->groups->ref)) { 5471 kfree(sd->groups->sgp); 5472 kfree(sd->groups); 5473 } 5474 kfree(sd); 5475} 5476 5477static void destroy_sched_domain(struct sched_domain *sd, int cpu) 5478{ 5479 call_rcu(&sd->rcu, free_sched_domain); 5480} 5481 5482static void destroy_sched_domains(struct sched_domain *sd, int cpu) 5483{ 5484 for (; sd; sd = sd->parent) 5485 destroy_sched_domain(sd, cpu); 5486} 5487 5488/* 5489 * Keep a special pointer to the highest sched_domain that has 5490 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this 5491 * allows us to avoid some pointer chasing select_idle_sibling(). 5492 * 5493 * Also keep a unique ID per domain (we use the first cpu number in 5494 * the cpumask of the domain), this allows us to quickly tell if 5495 * two cpus are in the same cache domain, see cpus_share_cache(). 5496 */ 5497DEFINE_PER_CPU(struct sched_domain *, sd_llc); 5498DEFINE_PER_CPU(int, sd_llc_size); 5499DEFINE_PER_CPU(int, sd_llc_id); 5500DEFINE_PER_CPU(struct sched_domain *, sd_numa); 5501DEFINE_PER_CPU(struct sched_domain *, sd_busy); 5502DEFINE_PER_CPU(struct sched_domain *, sd_asym); 5503 5504static void update_top_cache_domain(int cpu) 5505{ 5506 struct sched_domain *sd; 5507 struct sched_domain *busy_sd = NULL; 5508 int id = cpu; 5509 int size = 1; 5510 5511 sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES); 5512 if (sd) { 5513 id = cpumask_first(sched_domain_span(sd)); 5514 size = cpumask_weight(sched_domain_span(sd)); 5515 busy_sd = sd->parent; /* sd_busy */ 5516 } 5517 rcu_assign_pointer(per_cpu(sd_busy, cpu), busy_sd); 5518 5519 rcu_assign_pointer(per_cpu(sd_llc, cpu), sd); 5520 per_cpu(sd_llc_size, cpu) = size; 5521 per_cpu(sd_llc_id, cpu) = id; 5522 5523 sd = lowest_flag_domain(cpu, SD_NUMA); 5524 rcu_assign_pointer(per_cpu(sd_numa, cpu), sd); 5525 5526 sd = highest_flag_domain(cpu, SD_ASYM_PACKING); 5527 rcu_assign_pointer(per_cpu(sd_asym, cpu), sd); 5528} 5529 5530/* 5531 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must 5532 * hold the hotplug lock. 5533 */ 5534static void 5535cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) 5536{ 5537 struct rq *rq = cpu_rq(cpu); 5538 struct sched_domain *tmp; 5539 5540 /* Remove the sched domains which do not contribute to scheduling. */ 5541 for (tmp = sd; tmp; ) { 5542 struct sched_domain *parent = tmp->parent; 5543 if (!parent) 5544 break; 5545 5546 if (sd_parent_degenerate(tmp, parent)) { 5547 tmp->parent = parent->parent; 5548 if (parent->parent) 5549 parent->parent->child = tmp; 5550 /* 5551 * Transfer SD_PREFER_SIBLING down in case of a 5552 * degenerate parent; the spans match for this 5553 * so the property transfers. 5554 */ 5555 if (parent->flags & SD_PREFER_SIBLING) 5556 tmp->flags |= SD_PREFER_SIBLING; 5557 destroy_sched_domain(parent, cpu); 5558 } else 5559 tmp = tmp->parent; 5560 } 5561 5562 if (sd && sd_degenerate(sd)) { 5563 tmp = sd; 5564 sd = sd->parent; 5565 destroy_sched_domain(tmp, cpu); 5566 if (sd) 5567 sd->child = NULL; 5568 } 5569 5570 sched_domain_debug(sd, cpu); 5571 5572 rq_attach_root(rq, rd); 5573 tmp = rq->sd; 5574 rcu_assign_pointer(rq->sd, sd); 5575 destroy_sched_domains(tmp, cpu); 5576 5577 update_top_cache_domain(cpu); 5578} 5579 5580/* cpus with isolated domains */ 5581static cpumask_var_t cpu_isolated_map; 5582 5583/* Setup the mask of cpus configured for isolated domains */ 5584static int __init isolated_cpu_setup(char *str) 5585{ 5586 alloc_bootmem_cpumask_var(&cpu_isolated_map); 5587 cpulist_parse(str, cpu_isolated_map); 5588 return 1; 5589} 5590 5591__setup("isolcpus=", isolated_cpu_setup); 5592 5593static const struct cpumask *cpu_cpu_mask(int cpu) 5594{ 5595 return cpumask_of_node(cpu_to_node(cpu)); 5596} 5597 5598struct sd_data { 5599 struct sched_domain **__percpu sd; 5600 struct sched_group **__percpu sg; 5601 struct sched_group_power **__percpu sgp; 5602}; 5603 5604struct s_data { 5605 struct sched_domain ** __percpu sd; 5606 struct root_domain *rd; 5607}; 5608 5609enum s_alloc { 5610 sa_rootdomain, 5611 sa_sd, 5612 sa_sd_storage, 5613 sa_none, 5614}; 5615 5616struct sched_domain_topology_level; 5617 5618typedef struct sched_domain *(*sched_domain_init_f)(struct sched_domain_topology_level *tl, int cpu); 5619typedef const struct cpumask *(*sched_domain_mask_f)(int cpu); 5620 5621#define SDTL_OVERLAP 0x01 5622 5623struct sched_domain_topology_level { 5624 sched_domain_init_f init; 5625 sched_domain_mask_f mask; 5626 int flags; 5627 int numa_level; 5628 struct sd_data data; 5629}; 5630 5631/* 5632 * Build an iteration mask that can exclude certain CPUs from the upwards 5633 * domain traversal. 5634 * 5635 * Asymmetric node setups can result in situations where the domain tree is of 5636 * unequal depth, make sure to skip domains that already cover the entire 5637 * range. 5638 * 5639 * In that case build_sched_domains() will have terminated the iteration early 5640 * and our sibling sd spans will be empty. Domains should always include the 5641 * cpu they're built on, so check that. 5642 * 5643 */ 5644static void build_group_mask(struct sched_domain *sd, struct sched_group *sg) 5645{ 5646 const struct cpumask *span = sched_domain_span(sd); 5647 struct sd_data *sdd = sd->private; 5648 struct sched_domain *sibling; 5649 int i; 5650 5651 for_each_cpu(i, span) { 5652 sibling = *per_cpu_ptr(sdd->sd, i); 5653 if (!cpumask_test_cpu(i, sched_domain_span(sibling))) 5654 continue; 5655 5656 cpumask_set_cpu(i, sched_group_mask(sg)); 5657 } 5658} 5659 5660/* 5661 * Return the canonical balance cpu for this group, this is the first cpu 5662 * of this group that's also in the iteration mask. 5663 */ 5664int group_balance_cpu(struct sched_group *sg) 5665{ 5666 return cpumask_first_and(sched_group_cpus(sg), sched_group_mask(sg)); 5667} 5668 5669static int 5670build_overlap_sched_groups(struct sched_domain *sd, int cpu) 5671{ 5672 struct sched_group *first = NULL, *last = NULL, *groups = NULL, *sg; 5673 const struct cpumask *span = sched_domain_span(sd); 5674 struct cpumask *covered = sched_domains_tmpmask; 5675 struct sd_data *sdd = sd->private; 5676 struct sched_domain *child; 5677 int i; 5678 5679 cpumask_clear(covered); 5680 5681 for_each_cpu(i, span) { 5682 struct cpumask *sg_span; 5683 5684 if (cpumask_test_cpu(i, covered)) 5685 continue; 5686 5687 child = *per_cpu_ptr(sdd->sd, i); 5688 5689 /* See the comment near build_group_mask(). */ 5690 if (!cpumask_test_cpu(i, sched_domain_span(child))) 5691 continue; 5692 5693 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), 5694 GFP_KERNEL, cpu_to_node(cpu)); 5695 5696 if (!sg) 5697 goto fail; 5698 5699 sg_span = sched_group_cpus(sg); 5700 if (child->child) { 5701 child = child->child; 5702 cpumask_copy(sg_span, sched_domain_span(child)); 5703 } else 5704 cpumask_set_cpu(i, sg_span); 5705 5706 cpumask_or(covered, covered, sg_span); 5707 5708 sg->sgp = *per_cpu_ptr(sdd->sgp, i); 5709 if (atomic_inc_return(&sg->sgp->ref) == 1) 5710 build_group_mask(sd, sg); 5711 5712 /* 5713 * Initialize sgp->power such that even if we mess up the 5714 * domains and no possible iteration will get us here, we won't 5715 * die on a /0 trap. 5716 */ 5717 sg->sgp->power = SCHED_POWER_SCALE * cpumask_weight(sg_span); 5718 sg->sgp->power_orig = sg->sgp->power; 5719 5720 /* 5721 * Make sure the first group of this domain contains the 5722 * canonical balance cpu. Otherwise the sched_domain iteration 5723 * breaks. See update_sg_lb_stats(). 5724 */ 5725 if ((!groups && cpumask_test_cpu(cpu, sg_span)) || 5726 group_balance_cpu(sg) == cpu) 5727 groups = sg; 5728 5729 if (!first) 5730 first = sg; 5731 if (last) 5732 last->next = sg; 5733 last = sg; 5734 last->next = first; 5735 } 5736 sd->groups = groups; 5737 5738 return 0; 5739 5740fail: 5741 free_sched_groups(first, 0); 5742 5743 return -ENOMEM; 5744} 5745 5746static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg) 5747{ 5748 struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu); 5749 struct sched_domain *child = sd->child; 5750 5751 if (child) 5752 cpu = cpumask_first(sched_domain_span(child)); 5753 5754 if (sg) { 5755 *sg = *per_cpu_ptr(sdd->sg, cpu); 5756 (*sg)->sgp = *per_cpu_ptr(sdd->sgp, cpu); 5757 atomic_set(&(*sg)->sgp->ref, 1); /* for claim_allocations */ 5758 } 5759 5760 return cpu; 5761} 5762 5763/* 5764 * build_sched_groups will build a circular linked list of the groups 5765 * covered by the given span, and will set each group's ->cpumask correctly, 5766 * and ->cpu_power to 0. 5767 * 5768 * Assumes the sched_domain tree is fully constructed 5769 */ 5770static int 5771build_sched_groups(struct sched_domain *sd, int cpu) 5772{ 5773 struct sched_group *first = NULL, *last = NULL; 5774 struct sd_data *sdd = sd->private; 5775 const struct cpumask *span = sched_domain_span(sd); 5776 struct cpumask *covered; 5777 int i; 5778 5779 get_group(cpu, sdd, &sd->groups); 5780 atomic_inc(&sd->groups->ref); 5781 5782 if (cpu != cpumask_first(span)) 5783 return 0; 5784 5785 lockdep_assert_held(&sched_domains_mutex); 5786 covered = sched_domains_tmpmask; 5787 5788 cpumask_clear(covered); 5789 5790 for_each_cpu(i, span) { 5791 struct sched_group *sg; 5792 int group, j; 5793 5794 if (cpumask_test_cpu(i, covered)) 5795 continue; 5796 5797 group = get_group(i, sdd, &sg); 5798 cpumask_clear(sched_group_cpus(sg)); 5799 sg->sgp->power = 0; 5800 cpumask_setall(sched_group_mask(sg)); 5801 5802 for_each_cpu(j, span) { 5803 if (get_group(j, sdd, NULL) != group) 5804 continue; 5805 5806 cpumask_set_cpu(j, covered); 5807 cpumask_set_cpu(j, sched_group_cpus(sg)); 5808 } 5809 5810 if (!first) 5811 first = sg; 5812 if (last) 5813 last->next = sg; 5814 last = sg; 5815 } 5816 last->next = first; 5817 5818 return 0; 5819} 5820 5821/* 5822 * Initialize sched groups cpu_power. 5823 * 5824 * cpu_power indicates the capacity of sched group, which is used while 5825 * distributing the load between different sched groups in a sched domain. 5826 * Typically cpu_power for all the groups in a sched domain will be same unless 5827 * there are asymmetries in the topology. If there are asymmetries, group 5828 * having more cpu_power will pickup more load compared to the group having 5829 * less cpu_power. 5830 */ 5831static void init_sched_groups_power(int cpu, struct sched_domain *sd) 5832{ 5833 struct sched_group *sg = sd->groups; 5834 5835 WARN_ON(!sg); 5836 5837 do { 5838 sg->group_weight = cpumask_weight(sched_group_cpus(sg)); 5839 sg = sg->next; 5840 } while (sg != sd->groups); 5841 5842 if (cpu != group_balance_cpu(sg)) 5843 return; 5844 5845 update_group_power(sd, cpu); 5846 atomic_set(&sg->sgp->nr_busy_cpus, sg->group_weight); 5847} 5848 5849int __weak arch_sd_sibling_asym_packing(void) 5850{ 5851 return 0*SD_ASYM_PACKING; 5852} 5853 5854/* 5855 * Initializers for schedule domains 5856 * Non-inlined to reduce accumulated stack pressure in build_sched_domains() 5857 */ 5858 5859#ifdef CONFIG_SCHED_DEBUG 5860# define SD_INIT_NAME(sd, type) sd->name = #type 5861#else 5862# define SD_INIT_NAME(sd, type) do { } while (0) 5863#endif 5864 5865#define SD_INIT_FUNC(type) \ 5866static noinline struct sched_domain * \ 5867sd_init_##type(struct sched_domain_topology_level *tl, int cpu) \ 5868{ \ 5869 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); \ 5870 *sd = SD_##type##_INIT; \ 5871 SD_INIT_NAME(sd, type); \ 5872 sd->private = &tl->data; \ 5873 return sd; \ 5874} 5875 5876SD_INIT_FUNC(CPU) 5877#ifdef CONFIG_SCHED_SMT 5878 SD_INIT_FUNC(SIBLING) 5879#endif 5880#ifdef CONFIG_SCHED_MC 5881 SD_INIT_FUNC(MC) 5882#endif 5883#ifdef CONFIG_SCHED_BOOK 5884 SD_INIT_FUNC(BOOK) 5885#endif 5886 5887static int default_relax_domain_level = -1; 5888int sched_domain_level_max; 5889 5890static int __init setup_relax_domain_level(char *str) 5891{ 5892 if (kstrtoint(str, 0, &default_relax_domain_level)) 5893 pr_warn("Unable to set relax_domain_level\n"); 5894 5895 return 1; 5896} 5897__setup("relax_domain_level=", setup_relax_domain_level); 5898 5899static void set_domain_attribute(struct sched_domain *sd, 5900 struct sched_domain_attr *attr) 5901{ 5902 int request; 5903 5904 if (!attr || attr->relax_domain_level < 0) { 5905 if (default_relax_domain_level < 0) 5906 return; 5907 else 5908 request = default_relax_domain_level; 5909 } else 5910 request = attr->relax_domain_level; 5911 if (request < sd->level) { 5912 /* turn off idle balance on this domain */ 5913 sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); 5914 } else { 5915 /* turn on idle balance on this domain */ 5916 sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); 5917 } 5918} 5919 5920static void __sdt_free(const struct cpumask *cpu_map); 5921static int __sdt_alloc(const struct cpumask *cpu_map); 5922 5923static void __free_domain_allocs(struct s_data *d, enum s_alloc what, 5924 const struct cpumask *cpu_map) 5925{ 5926 switch (what) { 5927 case sa_rootdomain: 5928 if (!atomic_read(&d->rd->refcount)) 5929 free_rootdomain(&d->rd->rcu); /* fall through */ 5930 case sa_sd: 5931 free_percpu(d->sd); /* fall through */ 5932 case sa_sd_storage: 5933 __sdt_free(cpu_map); /* fall through */ 5934 case sa_none: 5935 break; 5936 } 5937} 5938 5939static enum s_alloc __visit_domain_allocation_hell(struct s_data *d, 5940 const struct cpumask *cpu_map) 5941{ 5942 memset(d, 0, sizeof(*d)); 5943 5944 if (__sdt_alloc(cpu_map)) 5945 return sa_sd_storage; 5946 d->sd = alloc_percpu(struct sched_domain *); 5947 if (!d->sd) 5948 return sa_sd_storage; 5949 d->rd = alloc_rootdomain(); 5950 if (!d->rd) 5951 return sa_sd; 5952 return sa_rootdomain; 5953} 5954 5955/* 5956 * NULL the sd_data elements we've used to build the sched_domain and 5957 * sched_group structure so that the subsequent __free_domain_allocs() 5958 * will not free the data we're using. 5959 */ 5960static void claim_allocations(int cpu, struct sched_domain *sd) 5961{ 5962 struct sd_data *sdd = sd->private; 5963 5964 WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd); 5965 *per_cpu_ptr(sdd->sd, cpu) = NULL; 5966 5967 if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref)) 5968 *per_cpu_ptr(sdd->sg, cpu) = NULL; 5969 5970 if (atomic_read(&(*per_cpu_ptr(sdd->sgp, cpu))->ref)) 5971 *per_cpu_ptr(sdd->sgp, cpu) = NULL; 5972} 5973 5974#ifdef CONFIG_SCHED_SMT 5975static const struct cpumask *cpu_smt_mask(int cpu) 5976{ 5977 return topology_thread_cpumask(cpu); 5978} 5979#endif 5980 5981/* 5982 * Topology list, bottom-up. 5983 */ 5984static struct sched_domain_topology_level default_topology[] = { 5985#ifdef CONFIG_SCHED_SMT 5986 { sd_init_SIBLING, cpu_smt_mask, }, 5987#endif 5988#ifdef CONFIG_SCHED_MC 5989 { sd_init_MC, cpu_coregroup_mask, }, 5990#endif 5991#ifdef CONFIG_SCHED_BOOK 5992 { sd_init_BOOK, cpu_book_mask, }, 5993#endif 5994 { sd_init_CPU, cpu_cpu_mask, }, 5995 { NULL, }, 5996}; 5997 5998static struct sched_domain_topology_level *sched_domain_topology = default_topology; 5999 6000#define for_each_sd_topology(tl) \ 6001 for (tl = sched_domain_topology; tl->init; tl++) 6002 6003#ifdef CONFIG_NUMA 6004 6005static int sched_domains_numa_levels; 6006static int *sched_domains_numa_distance; 6007static struct cpumask ***sched_domains_numa_masks; 6008static int sched_domains_curr_level; 6009 6010static inline int sd_local_flags(int level) 6011{ 6012 if (sched_domains_numa_distance[level] > RECLAIM_DISTANCE) 6013 return 0; 6014 6015 return SD_BALANCE_EXEC | SD_BALANCE_FORK | SD_WAKE_AFFINE; 6016} 6017 6018static struct sched_domain * 6019sd_numa_init(struct sched_domain_topology_level *tl, int cpu) 6020{ 6021 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); 6022 int level = tl->numa_level; 6023 int sd_weight = cpumask_weight( 6024 sched_domains_numa_masks[level][cpu_to_node(cpu)]); 6025 6026 *sd = (struct sched_domain){ 6027 .min_interval = sd_weight, 6028 .max_interval = 2*sd_weight, 6029 .busy_factor = 32, 6030 .imbalance_pct = 125, 6031 .cache_nice_tries = 2, 6032 .busy_idx = 3, 6033 .idle_idx = 2, 6034 .newidle_idx = 0, 6035 .wake_idx = 0, 6036 .forkexec_idx = 0, 6037 6038 .flags = 1*SD_LOAD_BALANCE 6039 | 1*SD_BALANCE_NEWIDLE 6040 | 0*SD_BALANCE_EXEC 6041 | 0*SD_BALANCE_FORK 6042 | 0*SD_BALANCE_WAKE 6043 | 0*SD_WAKE_AFFINE 6044 | 0*SD_SHARE_CPUPOWER 6045 | 0*SD_SHARE_PKG_RESOURCES 6046 | 1*SD_SERIALIZE 6047 | 0*SD_PREFER_SIBLING 6048 | 1*SD_NUMA 6049 | sd_local_flags(level) 6050 , 6051 .last_balance = jiffies, 6052 .balance_interval = sd_weight, 6053 .max_newidle_lb_cost = 0, 6054 .next_decay_max_lb_cost = jiffies, 6055 }; 6056 SD_INIT_NAME(sd, NUMA); 6057 sd->private = &tl->data; 6058 6059 /* 6060 * Ugly hack to pass state to sd_numa_mask()... 6061 */ 6062 sched_domains_curr_level = tl->numa_level; 6063 6064 return sd; 6065} 6066 6067static const struct cpumask *sd_numa_mask(int cpu) 6068{ 6069 return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)]; 6070} 6071 6072static void sched_numa_warn(const char *str) 6073{ 6074 static int done = false; 6075 int i,j; 6076 6077 if (done) 6078 return; 6079 6080 done = true; 6081 6082 printk(KERN_WARNING "ERROR: %s\n\n", str); 6083 6084 for (i = 0; i < nr_node_ids; i++) { 6085 printk(KERN_WARNING " "); 6086 for (j = 0; j < nr_node_ids; j++) 6087 printk(KERN_CONT "%02d ", node_distance(i,j)); 6088 printk(KERN_CONT "\n"); 6089 } 6090 printk(KERN_WARNING "\n"); 6091} 6092 6093static bool find_numa_distance(int distance) 6094{ 6095 int i; 6096 6097 if (distance == node_distance(0, 0)) 6098 return true; 6099 6100 for (i = 0; i < sched_domains_numa_levels; i++) { 6101 if (sched_domains_numa_distance[i] == distance) 6102 return true; 6103 } 6104 6105 return false; 6106} 6107 6108static void sched_init_numa(void) 6109{ 6110 int next_distance, curr_distance = node_distance(0, 0); 6111 struct sched_domain_topology_level *tl; 6112 int level = 0; 6113 int i, j, k; 6114 6115 sched_domains_numa_distance = kzalloc(sizeof(int) * nr_node_ids, GFP_KERNEL); 6116 if (!sched_domains_numa_distance) 6117 return; 6118 6119 /* 6120 * O(nr_nodes^2) deduplicating selection sort -- in order to find the 6121 * unique distances in the node_distance() table. 6122 * 6123 * Assumes node_distance(0,j) includes all distances in 6124 * node_distance(i,j) in order to avoid cubic time. 6125 */ 6126 next_distance = curr_distance; 6127 for (i = 0; i < nr_node_ids; i++) { 6128 for (j = 0; j < nr_node_ids; j++) { 6129 for (k = 0; k < nr_node_ids; k++) { 6130 int distance = node_distance(i, k); 6131 6132 if (distance > curr_distance && 6133 (distance < next_distance || 6134 next_distance == curr_distance)) 6135 next_distance = distance; 6136 6137 /* 6138 * While not a strong assumption it would be nice to know 6139 * about cases where if node A is connected to B, B is not 6140 * equally connected to A. 6141 */ 6142 if (sched_debug() && node_distance(k, i) != distance) 6143 sched_numa_warn("Node-distance not symmetric"); 6144 6145 if (sched_debug() && i && !find_numa_distance(distance)) 6146 sched_numa_warn("Node-0 not representative"); 6147 } 6148 if (next_distance != curr_distance) { 6149 sched_domains_numa_distance[level++] = next_distance; 6150 sched_domains_numa_levels = level; 6151 curr_distance = next_distance; 6152 } else break; 6153 } 6154 6155 /* 6156 * In case of sched_debug() we verify the above assumption. 6157 */ 6158 if (!sched_debug()) 6159 break; 6160 } 6161 /* 6162 * 'level' contains the number of unique distances, excluding the 6163 * identity distance node_distance(i,i). 6164 * 6165 * The sched_domains_numa_distance[] array includes the actual distance 6166 * numbers. 6167 */ 6168 6169 /* 6170 * Here, we should temporarily reset sched_domains_numa_levels to 0. 6171 * If it fails to allocate memory for array sched_domains_numa_masks[][], 6172 * the array will contain less then 'level' members. This could be 6173 * dangerous when we use it to iterate array sched_domains_numa_masks[][] 6174 * in other functions. 6175 * 6176 * We reset it to 'level' at the end of this function. 6177 */ 6178 sched_domains_numa_levels = 0; 6179 6180 sched_domains_numa_masks = kzalloc(sizeof(void *) * level, GFP_KERNEL); 6181 if (!sched_domains_numa_masks) 6182 return; 6183 6184 /* 6185 * Now for each level, construct a mask per node which contains all 6186 * cpus of nodes that are that many hops away from us. 6187 */ 6188 for (i = 0; i < level; i++) { 6189 sched_domains_numa_masks[i] = 6190 kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL); 6191 if (!sched_domains_numa_masks[i]) 6192 return; 6193 6194 for (j = 0; j < nr_node_ids; j++) { 6195 struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL); 6196 if (!mask) 6197 return; 6198 6199 sched_domains_numa_masks[i][j] = mask; 6200 6201 for (k = 0; k < nr_node_ids; k++) { 6202 if (node_distance(j, k) > sched_domains_numa_distance[i]) 6203 continue; 6204 6205 cpumask_or(mask, mask, cpumask_of_node(k)); 6206 } 6207 } 6208 } 6209 6210 tl = kzalloc((ARRAY_SIZE(default_topology) + level) * 6211 sizeof(struct sched_domain_topology_level), GFP_KERNEL); 6212 if (!tl) 6213 return; 6214 6215 /* 6216 * Copy the default topology bits.. 6217 */ 6218 for (i = 0; default_topology[i].init; i++) 6219 tl[i] = default_topology[i]; 6220 6221 /* 6222 * .. and append 'j' levels of NUMA goodness. 6223 */ 6224 for (j = 0; j < level; i++, j++) { 6225 tl[i] = (struct sched_domain_topology_level){ 6226 .init = sd_numa_init, 6227 .mask = sd_numa_mask, 6228 .flags = SDTL_OVERLAP, 6229 .numa_level = j, 6230 }; 6231 } 6232 6233 sched_domain_topology = tl; 6234 6235 sched_domains_numa_levels = level; 6236} 6237 6238static void sched_domains_numa_masks_set(int cpu) 6239{ 6240 int i, j; 6241 int node = cpu_to_node(cpu); 6242 6243 for (i = 0; i < sched_domains_numa_levels; i++) { 6244 for (j = 0; j < nr_node_ids; j++) { 6245 if (node_distance(j, node) <= sched_domains_numa_distance[i]) 6246 cpumask_set_cpu(cpu, sched_domains_numa_masks[i][j]); 6247 } 6248 } 6249} 6250 6251static void sched_domains_numa_masks_clear(int cpu) 6252{ 6253 int i, j; 6254 for (i = 0; i < sched_domains_numa_levels; i++) { 6255 for (j = 0; j < nr_node_ids; j++) 6256 cpumask_clear_cpu(cpu, sched_domains_numa_masks[i][j]); 6257 } 6258} 6259 6260/* 6261 * Update sched_domains_numa_masks[level][node] array when new cpus 6262 * are onlined. 6263 */ 6264static int sched_domains_numa_masks_update(struct notifier_block *nfb, 6265 unsigned long action, 6266 void *hcpu) 6267{ 6268 int cpu = (long)hcpu; 6269 6270 switch (action & ~CPU_TASKS_FROZEN) { 6271 case CPU_ONLINE: 6272 sched_domains_numa_masks_set(cpu); 6273 break; 6274 6275 case CPU_DEAD: 6276 sched_domains_numa_masks_clear(cpu); 6277 break; 6278 6279 default: 6280 return NOTIFY_DONE; 6281 } 6282 6283 return NOTIFY_OK; 6284} 6285#else 6286static inline void sched_init_numa(void) 6287{ 6288} 6289 6290static int sched_domains_numa_masks_update(struct notifier_block *nfb, 6291 unsigned long action, 6292 void *hcpu) 6293{ 6294 return 0; 6295} 6296#endif /* CONFIG_NUMA */ 6297 6298static int __sdt_alloc(const struct cpumask *cpu_map) 6299{ 6300 struct sched_domain_topology_level *tl; 6301 int j; 6302 6303 for_each_sd_topology(tl) { 6304 struct sd_data *sdd = &tl->data; 6305 6306 sdd->sd = alloc_percpu(struct sched_domain *); 6307 if (!sdd->sd) 6308 return -ENOMEM; 6309 6310 sdd->sg = alloc_percpu(struct sched_group *); 6311 if (!sdd->sg) 6312 return -ENOMEM; 6313 6314 sdd->sgp = alloc_percpu(struct sched_group_power *); 6315 if (!sdd->sgp) 6316 return -ENOMEM; 6317 6318 for_each_cpu(j, cpu_map) { 6319 struct sched_domain *sd; 6320 struct sched_group *sg; 6321 struct sched_group_power *sgp; 6322 6323 sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(), 6324 GFP_KERNEL, cpu_to_node(j)); 6325 if (!sd) 6326 return -ENOMEM; 6327 6328 *per_cpu_ptr(sdd->sd, j) = sd; 6329 6330 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), 6331 GFP_KERNEL, cpu_to_node(j)); 6332 if (!sg) 6333 return -ENOMEM; 6334 6335 sg->next = sg; 6336 6337 *per_cpu_ptr(sdd->sg, j) = sg; 6338 6339 sgp = kzalloc_node(sizeof(struct sched_group_power) + cpumask_size(), 6340 GFP_KERNEL, cpu_to_node(j)); 6341 if (!sgp) 6342 return -ENOMEM; 6343 6344 *per_cpu_ptr(sdd->sgp, j) = sgp; 6345 } 6346 } 6347 6348 return 0; 6349} 6350 6351static void __sdt_free(const struct cpumask *cpu_map) 6352{ 6353 struct sched_domain_topology_level *tl; 6354 int j; 6355 6356 for_each_sd_topology(tl) { 6357 struct sd_data *sdd = &tl->data; 6358 6359 for_each_cpu(j, cpu_map) { 6360 struct sched_domain *sd; 6361 6362 if (sdd->sd) { 6363 sd = *per_cpu_ptr(sdd->sd, j); 6364 if (sd && (sd->flags & SD_OVERLAP)) 6365 free_sched_groups(sd->groups, 0); 6366 kfree(*per_cpu_ptr(sdd->sd, j)); 6367 } 6368 6369 if (sdd->sg) 6370 kfree(*per_cpu_ptr(sdd->sg, j)); 6371 if (sdd->sgp) 6372 kfree(*per_cpu_ptr(sdd->sgp, j)); 6373 } 6374 free_percpu(sdd->sd); 6375 sdd->sd = NULL; 6376 free_percpu(sdd->sg); 6377 sdd->sg = NULL; 6378 free_percpu(sdd->sgp); 6379 sdd->sgp = NULL; 6380 } 6381} 6382 6383struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl, 6384 const struct cpumask *cpu_map, struct sched_domain_attr *attr, 6385 struct sched_domain *child, int cpu) 6386{ 6387 struct sched_domain *sd = tl->init(tl, cpu); 6388 if (!sd) 6389 return child; 6390 6391 cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu)); 6392 if (child) { 6393 sd->level = child->level + 1; 6394 sched_domain_level_max = max(sched_domain_level_max, sd->level); 6395 child->parent = sd; 6396 sd->child = child; 6397 } 6398 set_domain_attribute(sd, attr); 6399 6400 return sd; 6401} 6402 6403/* 6404 * Build sched domains for a given set of cpus and attach the sched domains 6405 * to the individual cpus 6406 */ 6407static int build_sched_domains(const struct cpumask *cpu_map, 6408 struct sched_domain_attr *attr) 6409{ 6410 enum s_alloc alloc_state; 6411 struct sched_domain *sd; 6412 struct s_data d; 6413 int i, ret = -ENOMEM; 6414 6415 alloc_state = __visit_domain_allocation_hell(&d, cpu_map); 6416 if (alloc_state != sa_rootdomain) 6417 goto error; 6418 6419 /* Set up domains for cpus specified by the cpu_map. */ 6420 for_each_cpu(i, cpu_map) { 6421 struct sched_domain_topology_level *tl; 6422 6423 sd = NULL; 6424 for_each_sd_topology(tl) { 6425 sd = build_sched_domain(tl, cpu_map, attr, sd, i); 6426 if (tl == sched_domain_topology) 6427 *per_cpu_ptr(d.sd, i) = sd; 6428 if (tl->flags & SDTL_OVERLAP || sched_feat(FORCE_SD_OVERLAP)) 6429 sd->flags |= SD_OVERLAP; 6430 if (cpumask_equal(cpu_map, sched_domain_span(sd))) 6431 break; 6432 } 6433 } 6434 6435 /* Build the groups for the domains */ 6436 for_each_cpu(i, cpu_map) { 6437 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { 6438 sd->span_weight = cpumask_weight(sched_domain_span(sd)); 6439 if (sd->flags & SD_OVERLAP) { 6440 if (build_overlap_sched_groups(sd, i)) 6441 goto error; 6442 } else { 6443 if (build_sched_groups(sd, i)) 6444 goto error; 6445 } 6446 } 6447 } 6448 6449 /* Calculate CPU power for physical packages and nodes */ 6450 for (i = nr_cpumask_bits-1; i >= 0; i--) { 6451 if (!cpumask_test_cpu(i, cpu_map)) 6452 continue; 6453 6454 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { 6455 claim_allocations(i, sd); 6456 init_sched_groups_power(i, sd); 6457 } 6458 } 6459 6460 /* Attach the domains */ 6461 rcu_read_lock(); 6462 for_each_cpu(i, cpu_map) { 6463 sd = *per_cpu_ptr(d.sd, i); 6464 cpu_attach_domain(sd, d.rd, i); 6465 } 6466 rcu_read_unlock(); 6467 6468 ret = 0; 6469error: 6470 __free_domain_allocs(&d, alloc_state, cpu_map); 6471 return ret; 6472} 6473 6474static cpumask_var_t *doms_cur; /* current sched domains */ 6475static int ndoms_cur; /* number of sched domains in 'doms_cur' */ 6476static struct sched_domain_attr *dattr_cur; 6477 /* attribues of custom domains in 'doms_cur' */ 6478 6479/* 6480 * Special case: If a kmalloc of a doms_cur partition (array of 6481 * cpumask) fails, then fallback to a single sched domain, 6482 * as determined by the single cpumask fallback_doms. 6483 */ 6484static cpumask_var_t fallback_doms; 6485 6486/* 6487 * arch_update_cpu_topology lets virtualized architectures update the 6488 * cpu core maps. It is supposed to return 1 if the topology changed 6489 * or 0 if it stayed the same. 6490 */ 6491int __weak arch_update_cpu_topology(void) 6492{ 6493 return 0; 6494} 6495 6496cpumask_var_t *alloc_sched_domains(unsigned int ndoms) 6497{ 6498 int i; 6499 cpumask_var_t *doms; 6500 6501 doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL); 6502 if (!doms) 6503 return NULL; 6504 for (i = 0; i < ndoms; i++) { 6505 if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) { 6506 free_sched_domains(doms, i); 6507 return NULL; 6508 } 6509 } 6510 return doms; 6511} 6512 6513void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms) 6514{ 6515 unsigned int i; 6516 for (i = 0; i < ndoms; i++) 6517 free_cpumask_var(doms[i]); 6518 kfree(doms); 6519} 6520 6521/* 6522 * Set up scheduler domains and groups. Callers must hold the hotplug lock. 6523 * For now this just excludes isolated cpus, but could be used to 6524 * exclude other special cases in the future. 6525 */ 6526static int init_sched_domains(const struct cpumask *cpu_map) 6527{ 6528 int err; 6529 6530 arch_update_cpu_topology(); 6531 ndoms_cur = 1; 6532 doms_cur = alloc_sched_domains(ndoms_cur); 6533 if (!doms_cur) 6534 doms_cur = &fallback_doms; 6535 cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map); 6536 err = build_sched_domains(doms_cur[0], NULL); 6537 register_sched_domain_sysctl(); 6538 6539 return err; 6540} 6541 6542/* 6543 * Detach sched domains from a group of cpus specified in cpu_map 6544 * These cpus will now be attached to the NULL domain 6545 */ 6546static void detach_destroy_domains(const struct cpumask *cpu_map) 6547{ 6548 int i; 6549 6550 rcu_read_lock(); 6551 for_each_cpu(i, cpu_map) 6552 cpu_attach_domain(NULL, &def_root_domain, i); 6553 rcu_read_unlock(); 6554} 6555 6556/* handle null as "default" */ 6557static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur, 6558 struct sched_domain_attr *new, int idx_new) 6559{ 6560 struct sched_domain_attr tmp; 6561 6562 /* fast path */ 6563 if (!new && !cur) 6564 return 1; 6565 6566 tmp = SD_ATTR_INIT; 6567 return !memcmp(cur ? (cur + idx_cur) : &tmp, 6568 new ? (new + idx_new) : &tmp, 6569 sizeof(struct sched_domain_attr)); 6570} 6571 6572/* 6573 * Partition sched domains as specified by the 'ndoms_new' 6574 * cpumasks in the array doms_new[] of cpumasks. This compares 6575 * doms_new[] to the current sched domain partitioning, doms_cur[]. 6576 * It destroys each deleted domain and builds each new domain. 6577 * 6578 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'. 6579 * The masks don't intersect (don't overlap.) We should setup one 6580 * sched domain for each mask. CPUs not in any of the cpumasks will 6581 * not be load balanced. If the same cpumask appears both in the 6582 * current 'doms_cur' domains and in the new 'doms_new', we can leave 6583 * it as it is. 6584 * 6585 * The passed in 'doms_new' should be allocated using 6586 * alloc_sched_domains. This routine takes ownership of it and will 6587 * free_sched_domains it when done with it. If the caller failed the 6588 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1, 6589 * and partition_sched_domains() will fallback to the single partition 6590 * 'fallback_doms', it also forces the domains to be rebuilt. 6591 * 6592 * If doms_new == NULL it will be replaced with cpu_online_mask. 6593 * ndoms_new == 0 is a special case for destroying existing domains, 6594 * and it will not create the default domain. 6595 * 6596 * Call with hotplug lock held 6597 */ 6598void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[], 6599 struct sched_domain_attr *dattr_new) 6600{ 6601 int i, j, n; 6602 int new_topology; 6603 6604 mutex_lock(&sched_domains_mutex); 6605 6606 /* always unregister in case we don't destroy any domains */ 6607 unregister_sched_domain_sysctl(); 6608 6609 /* Let architecture update cpu core mappings. */ 6610 new_topology = arch_update_cpu_topology(); 6611 6612 n = doms_new ? ndoms_new : 0; 6613 6614 /* Destroy deleted domains */ 6615 for (i = 0; i < ndoms_cur; i++) { 6616 for (j = 0; j < n && !new_topology; j++) { 6617 if (cpumask_equal(doms_cur[i], doms_new[j]) 6618 && dattrs_equal(dattr_cur, i, dattr_new, j)) 6619 goto match1; 6620 } 6621 /* no match - a current sched domain not in new doms_new[] */ 6622 detach_destroy_domains(doms_cur[i]); 6623match1: 6624 ; 6625 } 6626 6627 n = ndoms_cur; 6628 if (doms_new == NULL) { 6629 n = 0; 6630 doms_new = &fallback_doms; 6631 cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map); 6632 WARN_ON_ONCE(dattr_new); 6633 } 6634 6635 /* Build new domains */ 6636 for (i = 0; i < ndoms_new; i++) { 6637 for (j = 0; j < n && !new_topology; j++) { 6638 if (cpumask_equal(doms_new[i], doms_cur[j]) 6639 && dattrs_equal(dattr_new, i, dattr_cur, j)) 6640 goto match2; 6641 } 6642 /* no match - add a new doms_new */ 6643 build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL); 6644match2: 6645 ; 6646 } 6647 6648 /* Remember the new sched domains */ 6649 if (doms_cur != &fallback_doms) 6650 free_sched_domains(doms_cur, ndoms_cur); 6651 kfree(dattr_cur); /* kfree(NULL) is safe */ 6652 doms_cur = doms_new; 6653 dattr_cur = dattr_new; 6654 ndoms_cur = ndoms_new; 6655 6656 register_sched_domain_sysctl(); 6657 6658 mutex_unlock(&sched_domains_mutex); 6659} 6660 6661static int num_cpus_frozen; /* used to mark begin/end of suspend/resume */ 6662 6663/* 6664 * Update cpusets according to cpu_active mask. If cpusets are 6665 * disabled, cpuset_update_active_cpus() becomes a simple wrapper 6666 * around partition_sched_domains(). 6667 * 6668 * If we come here as part of a suspend/resume, don't touch cpusets because we 6669 * want to restore it back to its original state upon resume anyway. 6670 */ 6671static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action, 6672 void *hcpu) 6673{ 6674 switch (action) { 6675 case CPU_ONLINE_FROZEN: 6676 case CPU_DOWN_FAILED_FROZEN: 6677 6678 /* 6679 * num_cpus_frozen tracks how many CPUs are involved in suspend 6680 * resume sequence. As long as this is not the last online 6681 * operation in the resume sequence, just build a single sched 6682 * domain, ignoring cpusets. 6683 */ 6684 num_cpus_frozen--; 6685 if (likely(num_cpus_frozen)) { 6686 partition_sched_domains(1, NULL, NULL); 6687 break; 6688 } 6689 6690 /* 6691 * This is the last CPU online operation. So fall through and 6692 * restore the original sched domains by considering the 6693 * cpuset configurations. 6694 */ 6695 6696 case CPU_ONLINE: 6697 case CPU_DOWN_FAILED: 6698 cpuset_update_active_cpus(true); 6699 break; 6700 default: 6701 return NOTIFY_DONE; 6702 } 6703 return NOTIFY_OK; 6704} 6705 6706static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action, 6707 void *hcpu) 6708{ 6709 switch (action) { 6710 case CPU_DOWN_PREPARE: 6711 cpuset_update_active_cpus(false); 6712 break; 6713 case CPU_DOWN_PREPARE_FROZEN: 6714 num_cpus_frozen++; 6715 partition_sched_domains(1, NULL, NULL); 6716 break; 6717 default: 6718 return NOTIFY_DONE; 6719 } 6720 return NOTIFY_OK; 6721} 6722 6723void __init sched_init_smp(void) 6724{ 6725 cpumask_var_t non_isolated_cpus; 6726 6727 alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL); 6728 alloc_cpumask_var(&fallback_doms, GFP_KERNEL); 6729 6730 sched_init_numa(); 6731 6732 /* 6733 * There's no userspace yet to cause hotplug operations; hence all the 6734 * cpu masks are stable and all blatant races in the below code cannot 6735 * happen. 6736 */ 6737 mutex_lock(&sched_domains_mutex); 6738 init_sched_domains(cpu_active_mask); 6739 cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map); 6740 if (cpumask_empty(non_isolated_cpus)) 6741 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus); 6742 mutex_unlock(&sched_domains_mutex); 6743 6744 hotcpu_notifier(sched_domains_numa_masks_update, CPU_PRI_SCHED_ACTIVE); 6745 hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE); 6746 hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE); 6747 6748 init_hrtick(); 6749 6750 /* Move init over to a non-isolated CPU */ 6751 if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0) 6752 BUG(); 6753 sched_init_granularity(); 6754 free_cpumask_var(non_isolated_cpus); 6755 6756 init_sched_rt_class(); 6757 init_sched_dl_class(); 6758} 6759#else 6760void __init sched_init_smp(void) 6761{ 6762 sched_init_granularity(); 6763} 6764#endif /* CONFIG_SMP */ 6765 6766const_debug unsigned int sysctl_timer_migration = 1; 6767 6768int in_sched_functions(unsigned long addr) 6769{ 6770 return in_lock_functions(addr) || 6771 (addr >= (unsigned long)__sched_text_start 6772 && addr < (unsigned long)__sched_text_end); 6773} 6774 6775#ifdef CONFIG_CGROUP_SCHED 6776/* 6777 * Default task group. 6778 * Every task in system belongs to this group at bootup. 6779 */ 6780struct task_group root_task_group; 6781LIST_HEAD(task_groups); 6782#endif 6783 6784DECLARE_PER_CPU(cpumask_var_t, load_balance_mask); 6785 6786void __init sched_init(void) 6787{ 6788 int i, j; 6789 unsigned long alloc_size = 0, ptr; 6790 6791#ifdef CONFIG_FAIR_GROUP_SCHED 6792 alloc_size += 2 * nr_cpu_ids * sizeof(void **); 6793#endif 6794#ifdef CONFIG_RT_GROUP_SCHED 6795 alloc_size += 2 * nr_cpu_ids * sizeof(void **); 6796#endif 6797#ifdef CONFIG_CPUMASK_OFFSTACK 6798 alloc_size += num_possible_cpus() * cpumask_size(); 6799#endif 6800 if (alloc_size) { 6801 ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT); 6802 6803#ifdef CONFIG_FAIR_GROUP_SCHED 6804 root_task_group.se = (struct sched_entity **)ptr; 6805 ptr += nr_cpu_ids * sizeof(void **); 6806 6807 root_task_group.cfs_rq = (struct cfs_rq **)ptr; 6808 ptr += nr_cpu_ids * sizeof(void **); 6809 6810#endif /* CONFIG_FAIR_GROUP_SCHED */ 6811#ifdef CONFIG_RT_GROUP_SCHED 6812 root_task_group.rt_se = (struct sched_rt_entity **)ptr; 6813 ptr += nr_cpu_ids * sizeof(void **); 6814 6815 root_task_group.rt_rq = (struct rt_rq **)ptr; 6816 ptr += nr_cpu_ids * sizeof(void **); 6817 6818#endif /* CONFIG_RT_GROUP_SCHED */ 6819#ifdef CONFIG_CPUMASK_OFFSTACK 6820 for_each_possible_cpu(i) { 6821 per_cpu(load_balance_mask, i) = (void *)ptr; 6822 ptr += cpumask_size(); 6823 } 6824#endif /* CONFIG_CPUMASK_OFFSTACK */ 6825 } 6826 6827 init_rt_bandwidth(&def_rt_bandwidth, 6828 global_rt_period(), global_rt_runtime()); 6829 init_dl_bandwidth(&def_dl_bandwidth, 6830 global_rt_period(), global_rt_runtime()); 6831 6832#ifdef CONFIG_SMP 6833 init_defrootdomain(); 6834#endif 6835 6836#ifdef CONFIG_RT_GROUP_SCHED 6837 init_rt_bandwidth(&root_task_group.rt_bandwidth, 6838 global_rt_period(), global_rt_runtime()); 6839#endif /* CONFIG_RT_GROUP_SCHED */ 6840 6841#ifdef CONFIG_CGROUP_SCHED 6842 list_add(&root_task_group.list, &task_groups); 6843 INIT_LIST_HEAD(&root_task_group.children); 6844 INIT_LIST_HEAD(&root_task_group.siblings); 6845 autogroup_init(&init_task); 6846 6847#endif /* CONFIG_CGROUP_SCHED */ 6848 6849 for_each_possible_cpu(i) { 6850 struct rq *rq; 6851 6852 rq = cpu_rq(i); 6853 raw_spin_lock_init(&rq->lock); 6854 rq->nr_running = 0; 6855 rq->calc_load_active = 0; 6856 rq->calc_load_update = jiffies + LOAD_FREQ; 6857 init_cfs_rq(&rq->cfs); 6858 init_rt_rq(&rq->rt, rq); 6859 init_dl_rq(&rq->dl, rq); 6860#ifdef CONFIG_FAIR_GROUP_SCHED 6861 root_task_group.shares = ROOT_TASK_GROUP_LOAD; 6862 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list); 6863 /* 6864 * How much cpu bandwidth does root_task_group get? 6865 * 6866 * In case of task-groups formed thr' the cgroup filesystem, it 6867 * gets 100% of the cpu resources in the system. This overall 6868 * system cpu resource is divided among the tasks of 6869 * root_task_group and its child task-groups in a fair manner, 6870 * based on each entity's (task or task-group's) weight 6871 * (se->load.weight). 6872 * 6873 * In other words, if root_task_group has 10 tasks of weight 6874 * 1024) and two child groups A0 and A1 (of weight 1024 each), 6875 * then A0's share of the cpu resource is: 6876 * 6877 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33% 6878 * 6879 * We achieve this by letting root_task_group's tasks sit 6880 * directly in rq->cfs (i.e root_task_group->se[] = NULL). 6881 */ 6882 init_cfs_bandwidth(&root_task_group.cfs_bandwidth); 6883 init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL); 6884#endif /* CONFIG_FAIR_GROUP_SCHED */ 6885 6886 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime; 6887#ifdef CONFIG_RT_GROUP_SCHED 6888 init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL); 6889#endif 6890 6891 for (j = 0; j < CPU_LOAD_IDX_MAX; j++) 6892 rq->cpu_load[j] = 0; 6893 6894 rq->last_load_update_tick = jiffies; 6895 6896#ifdef CONFIG_SMP 6897 rq->sd = NULL; 6898 rq->rd = NULL; 6899 rq->cpu_power = SCHED_POWER_SCALE; 6900 rq->post_schedule = 0; 6901 rq->active_balance = 0; 6902 rq->next_balance = jiffies; 6903 rq->push_cpu = 0; 6904 rq->cpu = i; 6905 rq->online = 0; 6906 rq->idle_stamp = 0; 6907 rq->avg_idle = 2*sysctl_sched_migration_cost; 6908 rq->max_idle_balance_cost = sysctl_sched_migration_cost; 6909 6910 INIT_LIST_HEAD(&rq->cfs_tasks); 6911 6912 rq_attach_root(rq, &def_root_domain); 6913#ifdef CONFIG_NO_HZ_COMMON 6914 rq->nohz_flags = 0; 6915#endif 6916#ifdef CONFIG_NO_HZ_FULL 6917 rq->last_sched_tick = 0; 6918#endif 6919#endif 6920 init_rq_hrtick(rq); 6921 atomic_set(&rq->nr_iowait, 0); 6922 } 6923 6924 set_load_weight(&init_task); 6925 6926#ifdef CONFIG_PREEMPT_NOTIFIERS 6927 INIT_HLIST_HEAD(&init_task.preempt_notifiers); 6928#endif 6929 6930 /* 6931 * The boot idle thread does lazy MMU switching as well: 6932 */ 6933 atomic_inc(&init_mm.mm_count); 6934 enter_lazy_tlb(&init_mm, current); 6935 6936 /* 6937 * Make us the idle thread. Technically, schedule() should not be 6938 * called from this thread, however somewhere below it might be, 6939 * but because we are the idle thread, we just pick up running again 6940 * when this runqueue becomes "idle". 6941 */ 6942 init_idle(current, smp_processor_id()); 6943 6944 calc_load_update = jiffies + LOAD_FREQ; 6945 6946 /* 6947 * During early bootup we pretend to be a normal task: 6948 */ 6949 current->sched_class = &fair_sched_class; 6950 6951#ifdef CONFIG_SMP 6952 zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT); 6953 /* May be allocated at isolcpus cmdline parse time */ 6954 if (cpu_isolated_map == NULL) 6955 zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT); 6956 idle_thread_set_boot_cpu(); 6957#endif 6958 init_sched_fair_class(); 6959 6960 scheduler_running = 1; 6961} 6962 6963#ifdef CONFIG_DEBUG_ATOMIC_SLEEP 6964static inline int preempt_count_equals(int preempt_offset) 6965{ 6966 int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth(); 6967 6968 return (nested == preempt_offset); 6969} 6970 6971void __might_sleep(const char *file, int line, int preempt_offset) 6972{ 6973 static unsigned long prev_jiffy; /* ratelimiting */ 6974 6975 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */ 6976 if ((preempt_count_equals(preempt_offset) && !irqs_disabled() && 6977 !is_idle_task(current)) || 6978 system_state != SYSTEM_RUNNING || oops_in_progress) 6979 return; 6980 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) 6981 return; 6982 prev_jiffy = jiffies; 6983 6984 printk(KERN_ERR 6985 "BUG: sleeping function called from invalid context at %s:%d\n", 6986 file, line); 6987 printk(KERN_ERR 6988 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n", 6989 in_atomic(), irqs_disabled(), 6990 current->pid, current->comm); 6991 6992 debug_show_held_locks(current); 6993 if (irqs_disabled()) 6994 print_irqtrace_events(current); 6995#ifdef CONFIG_DEBUG_PREEMPT 6996 if (!preempt_count_equals(preempt_offset)) { 6997 pr_err("Preemption disabled at:"); 6998 print_ip_sym(current->preempt_disable_ip); 6999 pr_cont("\n"); 7000 } 7001#endif 7002 dump_stack(); 7003} 7004EXPORT_SYMBOL(__might_sleep); 7005#endif 7006 7007#ifdef CONFIG_MAGIC_SYSRQ 7008static void normalize_task(struct rq *rq, struct task_struct *p) 7009{ 7010 const struct sched_class *prev_class = p->sched_class; 7011 struct sched_attr attr = { 7012 .sched_policy = SCHED_NORMAL, 7013 }; 7014 int old_prio = p->prio; 7015 int on_rq; 7016 7017 on_rq = p->on_rq; 7018 if (on_rq) 7019 dequeue_task(rq, p, 0); 7020 __setscheduler(rq, p, &attr); 7021 if (on_rq) { 7022 enqueue_task(rq, p, 0); 7023 resched_task(rq->curr); 7024 } 7025 7026 check_class_changed(rq, p, prev_class, old_prio); 7027} 7028 7029void normalize_rt_tasks(void) 7030{ 7031 struct task_struct *g, *p; 7032 unsigned long flags; 7033 struct rq *rq; 7034 7035 read_lock_irqsave(&tasklist_lock, flags); 7036 do_each_thread(g, p) { 7037 /* 7038 * Only normalize user tasks: 7039 */ 7040 if (!p->mm) 7041 continue; 7042 7043 p->se.exec_start = 0; 7044#ifdef CONFIG_SCHEDSTATS 7045 p->se.statistics.wait_start = 0; 7046 p->se.statistics.sleep_start = 0; 7047 p->se.statistics.block_start = 0; 7048#endif 7049 7050 if (!dl_task(p) && !rt_task(p)) { 7051 /* 7052 * Renice negative nice level userspace 7053 * tasks back to 0: 7054 */ 7055 if (task_nice(p) < 0 && p->mm) 7056 set_user_nice(p, 0); 7057 continue; 7058 } 7059 7060 raw_spin_lock(&p->pi_lock); 7061 rq = __task_rq_lock(p); 7062 7063 normalize_task(rq, p); 7064 7065 __task_rq_unlock(rq); 7066 raw_spin_unlock(&p->pi_lock); 7067 } while_each_thread(g, p); 7068 7069 read_unlock_irqrestore(&tasklist_lock, flags); 7070} 7071 7072#endif /* CONFIG_MAGIC_SYSRQ */ 7073 7074#if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) 7075/* 7076 * These functions are only useful for the IA64 MCA handling, or kdb. 7077 * 7078 * They can only be called when the whole system has been 7079 * stopped - every CPU needs to be quiescent, and no scheduling 7080 * activity can take place. Using them for anything else would 7081 * be a serious bug, and as a result, they aren't even visible 7082 * under any other configuration. 7083 */ 7084 7085/** 7086 * curr_task - return the current task for a given cpu. 7087 * @cpu: the processor in question. 7088 * 7089 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! 7090 * 7091 * Return: The current task for @cpu. 7092 */ 7093struct task_struct *curr_task(int cpu) 7094{ 7095 return cpu_curr(cpu); 7096} 7097 7098#endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */ 7099 7100#ifdef CONFIG_IA64 7101/** 7102 * set_curr_task - set the current task for a given cpu. 7103 * @cpu: the processor in question. 7104 * @p: the task pointer to set. 7105 * 7106 * Description: This function must only be used when non-maskable interrupts 7107 * are serviced on a separate stack. It allows the architecture to switch the 7108 * notion of the current task on a cpu in a non-blocking manner. This function 7109 * must be called with all CPU's synchronized, and interrupts disabled, the 7110 * and caller must save the original value of the current task (see 7111 * curr_task() above) and restore that value before reenabling interrupts and 7112 * re-starting the system. 7113 * 7114 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! 7115 */ 7116void set_curr_task(int cpu, struct task_struct *p) 7117{ 7118 cpu_curr(cpu) = p; 7119} 7120 7121#endif 7122 7123#ifdef CONFIG_CGROUP_SCHED 7124/* task_group_lock serializes the addition/removal of task groups */ 7125static DEFINE_SPINLOCK(task_group_lock); 7126 7127static void free_sched_group(struct task_group *tg) 7128{ 7129 free_fair_sched_group(tg); 7130 free_rt_sched_group(tg); 7131 autogroup_free(tg); 7132 kfree(tg); 7133} 7134 7135/* allocate runqueue etc for a new task group */ 7136struct task_group *sched_create_group(struct task_group *parent) 7137{ 7138 struct task_group *tg; 7139 7140 tg = kzalloc(sizeof(*tg), GFP_KERNEL); 7141 if (!tg) 7142 return ERR_PTR(-ENOMEM); 7143 7144 if (!alloc_fair_sched_group(tg, parent)) 7145 goto err; 7146 7147 if (!alloc_rt_sched_group(tg, parent)) 7148 goto err; 7149 7150 return tg; 7151 7152err: 7153 free_sched_group(tg); 7154 return ERR_PTR(-ENOMEM); 7155} 7156 7157void sched_online_group(struct task_group *tg, struct task_group *parent) 7158{ 7159 unsigned long flags; 7160 7161 spin_lock_irqsave(&task_group_lock, flags); 7162 list_add_rcu(&tg->list, &task_groups); 7163 7164 WARN_ON(!parent); /* root should already exist */ 7165 7166 tg->parent = parent; 7167 INIT_LIST_HEAD(&tg->children); 7168 list_add_rcu(&tg->siblings, &parent->children); 7169 spin_unlock_irqrestore(&task_group_lock, flags); 7170} 7171 7172/* rcu callback to free various structures associated with a task group */ 7173static void free_sched_group_rcu(struct rcu_head *rhp) 7174{ 7175 /* now it should be safe to free those cfs_rqs */ 7176 free_sched_group(container_of(rhp, struct task_group, rcu)); 7177} 7178 7179/* Destroy runqueue etc associated with a task group */ 7180void sched_destroy_group(struct task_group *tg) 7181{ 7182 /* wait for possible concurrent references to cfs_rqs complete */ 7183 call_rcu(&tg->rcu, free_sched_group_rcu); 7184} 7185 7186void sched_offline_group(struct task_group *tg) 7187{ 7188 unsigned long flags; 7189 int i; 7190 7191 /* end participation in shares distribution */ 7192 for_each_possible_cpu(i) 7193 unregister_fair_sched_group(tg, i); 7194 7195 spin_lock_irqsave(&task_group_lock, flags); 7196 list_del_rcu(&tg->list); 7197 list_del_rcu(&tg->siblings); 7198 spin_unlock_irqrestore(&task_group_lock, flags); 7199} 7200 7201/* change task's runqueue when it moves between groups. 7202 * The caller of this function should have put the task in its new group 7203 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to 7204 * reflect its new group. 7205 */ 7206void sched_move_task(struct task_struct *tsk) 7207{ 7208 struct task_group *tg; 7209 int on_rq, running; 7210 unsigned long flags; 7211 struct rq *rq; 7212 7213 rq = task_rq_lock(tsk, &flags); 7214 7215 running = task_current(rq, tsk); 7216 on_rq = tsk->on_rq; 7217 7218 if (on_rq) 7219 dequeue_task(rq, tsk, 0); 7220 if (unlikely(running)) 7221 tsk->sched_class->put_prev_task(rq, tsk); 7222 7223 tg = container_of(task_css_check(tsk, cpu_cgrp_id, 7224 lockdep_is_held(&tsk->sighand->siglock)), 7225 struct task_group, css); 7226 tg = autogroup_task_group(tsk, tg); 7227 tsk->sched_task_group = tg; 7228 7229#ifdef CONFIG_FAIR_GROUP_SCHED 7230 if (tsk->sched_class->task_move_group) 7231 tsk->sched_class->task_move_group(tsk, on_rq); 7232 else 7233#endif 7234 set_task_rq(tsk, task_cpu(tsk)); 7235 7236 if (unlikely(running)) 7237 tsk->sched_class->set_curr_task(rq); 7238 if (on_rq) 7239 enqueue_task(rq, tsk, 0); 7240 7241 task_rq_unlock(rq, tsk, &flags); 7242} 7243#endif /* CONFIG_CGROUP_SCHED */ 7244 7245#ifdef CONFIG_RT_GROUP_SCHED 7246/* 7247 * Ensure that the real time constraints are schedulable. 7248 */ 7249static DEFINE_MUTEX(rt_constraints_mutex); 7250 7251/* Must be called with tasklist_lock held */ 7252static inline int tg_has_rt_tasks(struct task_group *tg) 7253{ 7254 struct task_struct *g, *p; 7255 7256 do_each_thread(g, p) { 7257 if (rt_task(p) && task_rq(p)->rt.tg == tg) 7258 return 1; 7259 } while_each_thread(g, p); 7260 7261 return 0; 7262} 7263 7264struct rt_schedulable_data { 7265 struct task_group *tg; 7266 u64 rt_period; 7267 u64 rt_runtime; 7268}; 7269 7270static int tg_rt_schedulable(struct task_group *tg, void *data) 7271{ 7272 struct rt_schedulable_data *d = data; 7273 struct task_group *child; 7274 unsigned long total, sum = 0; 7275 u64 period, runtime; 7276 7277 period = ktime_to_ns(tg->rt_bandwidth.rt_period); 7278 runtime = tg->rt_bandwidth.rt_runtime; 7279 7280 if (tg == d->tg) { 7281 period = d->rt_period; 7282 runtime = d->rt_runtime; 7283 } 7284 7285 /* 7286 * Cannot have more runtime than the period. 7287 */ 7288 if (runtime > period && runtime != RUNTIME_INF) 7289 return -EINVAL; 7290 7291 /* 7292 * Ensure we don't starve existing RT tasks. 7293 */ 7294 if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg)) 7295 return -EBUSY; 7296 7297 total = to_ratio(period, runtime); 7298 7299 /* 7300 * Nobody can have more than the global setting allows. 7301 */ 7302 if (total > to_ratio(global_rt_period(), global_rt_runtime())) 7303 return -EINVAL; 7304 7305 /* 7306 * The sum of our children's runtime should not exceed our own. 7307 */ 7308 list_for_each_entry_rcu(child, &tg->children, siblings) { 7309 period = ktime_to_ns(child->rt_bandwidth.rt_period); 7310 runtime = child->rt_bandwidth.rt_runtime; 7311 7312 if (child == d->tg) { 7313 period = d->rt_period; 7314 runtime = d->rt_runtime; 7315 } 7316 7317 sum += to_ratio(period, runtime); 7318 } 7319 7320 if (sum > total) 7321 return -EINVAL; 7322 7323 return 0; 7324} 7325 7326static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime) 7327{ 7328 int ret; 7329 7330 struct rt_schedulable_data data = { 7331 .tg = tg, 7332 .rt_period = period, 7333 .rt_runtime = runtime, 7334 }; 7335 7336 rcu_read_lock(); 7337 ret = walk_tg_tree(tg_rt_schedulable, tg_nop, &data); 7338 rcu_read_unlock(); 7339 7340 return ret; 7341} 7342 7343static int tg_set_rt_bandwidth(struct task_group *tg, 7344 u64 rt_period, u64 rt_runtime) 7345{ 7346 int i, err = 0; 7347 7348 mutex_lock(&rt_constraints_mutex); 7349 read_lock(&tasklist_lock); 7350 err = __rt_schedulable(tg, rt_period, rt_runtime); 7351 if (err) 7352 goto unlock; 7353 7354 raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock); 7355 tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period); 7356 tg->rt_bandwidth.rt_runtime = rt_runtime; 7357 7358 for_each_possible_cpu(i) { 7359 struct rt_rq *rt_rq = tg->rt_rq[i]; 7360 7361 raw_spin_lock(&rt_rq->rt_runtime_lock); 7362 rt_rq->rt_runtime = rt_runtime; 7363 raw_spin_unlock(&rt_rq->rt_runtime_lock); 7364 } 7365 raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock); 7366unlock: 7367 read_unlock(&tasklist_lock); 7368 mutex_unlock(&rt_constraints_mutex); 7369 7370 return err; 7371} 7372 7373static int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us) 7374{ 7375 u64 rt_runtime, rt_period; 7376 7377 rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period); 7378 rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC; 7379 if (rt_runtime_us < 0) 7380 rt_runtime = RUNTIME_INF; 7381 7382 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); 7383} 7384 7385static long sched_group_rt_runtime(struct task_group *tg) 7386{ 7387 u64 rt_runtime_us; 7388 7389 if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF) 7390 return -1; 7391 7392 rt_runtime_us = tg->rt_bandwidth.rt_runtime; 7393 do_div(rt_runtime_us, NSEC_PER_USEC); 7394 return rt_runtime_us; 7395} 7396 7397static int sched_group_set_rt_period(struct task_group *tg, long rt_period_us) 7398{ 7399 u64 rt_runtime, rt_period; 7400 7401 rt_period = (u64)rt_period_us * NSEC_PER_USEC; 7402 rt_runtime = tg->rt_bandwidth.rt_runtime; 7403 7404 if (rt_period == 0) 7405 return -EINVAL; 7406 7407 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); 7408} 7409 7410static long sched_group_rt_period(struct task_group *tg) 7411{ 7412 u64 rt_period_us; 7413 7414 rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period); 7415 do_div(rt_period_us, NSEC_PER_USEC); 7416 return rt_period_us; 7417} 7418#endif /* CONFIG_RT_GROUP_SCHED */ 7419 7420#ifdef CONFIG_RT_GROUP_SCHED 7421static int sched_rt_global_constraints(void) 7422{ 7423 int ret = 0; 7424 7425 mutex_lock(&rt_constraints_mutex); 7426 read_lock(&tasklist_lock); 7427 ret = __rt_schedulable(NULL, 0, 0); 7428 read_unlock(&tasklist_lock); 7429 mutex_unlock(&rt_constraints_mutex); 7430 7431 return ret; 7432} 7433 7434static int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk) 7435{ 7436 /* Don't accept realtime tasks when there is no way for them to run */ 7437 if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0) 7438 return 0; 7439 7440 return 1; 7441} 7442 7443#else /* !CONFIG_RT_GROUP_SCHED */ 7444static int sched_rt_global_constraints(void) 7445{ 7446 unsigned long flags; 7447 int i, ret = 0; 7448 7449 raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags); 7450 for_each_possible_cpu(i) { 7451 struct rt_rq *rt_rq = &cpu_rq(i)->rt; 7452 7453 raw_spin_lock(&rt_rq->rt_runtime_lock); 7454 rt_rq->rt_runtime = global_rt_runtime(); 7455 raw_spin_unlock(&rt_rq->rt_runtime_lock); 7456 } 7457 raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags); 7458 7459 return ret; 7460} 7461#endif /* CONFIG_RT_GROUP_SCHED */ 7462 7463static int sched_dl_global_constraints(void) 7464{ 7465 u64 runtime = global_rt_runtime(); 7466 u64 period = global_rt_period(); 7467 u64 new_bw = to_ratio(period, runtime); 7468 int cpu, ret = 0; 7469 unsigned long flags; 7470 7471 /* 7472 * Here we want to check the bandwidth not being set to some 7473 * value smaller than the currently allocated bandwidth in 7474 * any of the root_domains. 7475 * 7476 * FIXME: Cycling on all the CPUs is overdoing, but simpler than 7477 * cycling on root_domains... Discussion on different/better 7478 * solutions is welcome! 7479 */ 7480 for_each_possible_cpu(cpu) { 7481 struct dl_bw *dl_b = dl_bw_of(cpu); 7482 7483 raw_spin_lock_irqsave(&dl_b->lock, flags); 7484 if (new_bw < dl_b->total_bw) 7485 ret = -EBUSY; 7486 raw_spin_unlock_irqrestore(&dl_b->lock, flags); 7487 7488 if (ret) 7489 break; 7490 } 7491 7492 return ret; 7493} 7494 7495static void sched_dl_do_global(void) 7496{ 7497 u64 new_bw = -1; 7498 int cpu; 7499 unsigned long flags; 7500 7501 def_dl_bandwidth.dl_period = global_rt_period(); 7502 def_dl_bandwidth.dl_runtime = global_rt_runtime(); 7503 7504 if (global_rt_runtime() != RUNTIME_INF) 7505 new_bw = to_ratio(global_rt_period(), global_rt_runtime()); 7506 7507 /* 7508 * FIXME: As above... 7509 */ 7510 for_each_possible_cpu(cpu) { 7511 struct dl_bw *dl_b = dl_bw_of(cpu); 7512 7513 raw_spin_lock_irqsave(&dl_b->lock, flags); 7514 dl_b->bw = new_bw; 7515 raw_spin_unlock_irqrestore(&dl_b->lock, flags); 7516 } 7517} 7518 7519static int sched_rt_global_validate(void) 7520{ 7521 if (sysctl_sched_rt_period <= 0) 7522 return -EINVAL; 7523 7524 if ((sysctl_sched_rt_runtime != RUNTIME_INF) && 7525 (sysctl_sched_rt_runtime > sysctl_sched_rt_period)) 7526 return -EINVAL; 7527 7528 return 0; 7529} 7530 7531static void sched_rt_do_global(void) 7532{ 7533 def_rt_bandwidth.rt_runtime = global_rt_runtime(); 7534 def_rt_bandwidth.rt_period = ns_to_ktime(global_rt_period()); 7535} 7536 7537int sched_rt_handler(struct ctl_table *table, int write, 7538 void __user *buffer, size_t *lenp, 7539 loff_t *ppos) 7540{ 7541 int old_period, old_runtime; 7542 static DEFINE_MUTEX(mutex); 7543 int ret; 7544 7545 mutex_lock(&mutex); 7546 old_period = sysctl_sched_rt_period; 7547 old_runtime = sysctl_sched_rt_runtime; 7548 7549 ret = proc_dointvec(table, write, buffer, lenp, ppos); 7550 7551 if (!ret && write) { 7552 ret = sched_rt_global_validate(); 7553 if (ret) 7554 goto undo; 7555 7556 ret = sched_rt_global_constraints(); 7557 if (ret) 7558 goto undo; 7559 7560 ret = sched_dl_global_constraints(); 7561 if (ret) 7562 goto undo; 7563 7564 sched_rt_do_global(); 7565 sched_dl_do_global(); 7566 } 7567 if (0) { 7568undo: 7569 sysctl_sched_rt_period = old_period; 7570 sysctl_sched_rt_runtime = old_runtime; 7571 } 7572 mutex_unlock(&mutex); 7573 7574 return ret; 7575} 7576 7577int sched_rr_handler(struct ctl_table *table, int write, 7578 void __user *buffer, size_t *lenp, 7579 loff_t *ppos) 7580{ 7581 int ret; 7582 static DEFINE_MUTEX(mutex); 7583 7584 mutex_lock(&mutex); 7585 ret = proc_dointvec(table, write, buffer, lenp, ppos); 7586 /* make sure that internally we keep jiffies */ 7587 /* also, writing zero resets timeslice to default */ 7588 if (!ret && write) { 7589 sched_rr_timeslice = sched_rr_timeslice <= 0 ? 7590 RR_TIMESLICE : msecs_to_jiffies(sched_rr_timeslice); 7591 } 7592 mutex_unlock(&mutex); 7593 return ret; 7594} 7595 7596#ifdef CONFIG_CGROUP_SCHED 7597 7598static inline struct task_group *css_tg(struct cgroup_subsys_state *css) 7599{ 7600 return css ? container_of(css, struct task_group, css) : NULL; 7601} 7602 7603static struct cgroup_subsys_state * 7604cpu_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) 7605{ 7606 struct task_group *parent = css_tg(parent_css); 7607 struct task_group *tg; 7608 7609 if (!parent) { 7610 /* This is early initialization for the top cgroup */ 7611 return &root_task_group.css; 7612 } 7613 7614 tg = sched_create_group(parent); 7615 if (IS_ERR(tg)) 7616 return ERR_PTR(-ENOMEM); 7617 7618 return &tg->css; 7619} 7620 7621static int cpu_cgroup_css_online(struct cgroup_subsys_state *css) 7622{ 7623 struct task_group *tg = css_tg(css); 7624 struct task_group *parent = css_tg(css_parent(css)); 7625 7626 if (parent) 7627 sched_online_group(tg, parent); 7628 return 0; 7629} 7630 7631static void cpu_cgroup_css_free(struct cgroup_subsys_state *css) 7632{ 7633 struct task_group *tg = css_tg(css); 7634 7635 sched_destroy_group(tg); 7636} 7637 7638static void cpu_cgroup_css_offline(struct cgroup_subsys_state *css) 7639{ 7640 struct task_group *tg = css_tg(css); 7641 7642 sched_offline_group(tg); 7643} 7644 7645static int cpu_cgroup_can_attach(struct cgroup_subsys_state *css, 7646 struct cgroup_taskset *tset) 7647{ 7648 struct task_struct *task; 7649 7650 cgroup_taskset_for_each(task, tset) { 7651#ifdef CONFIG_RT_GROUP_SCHED 7652 if (!sched_rt_can_attach(css_tg(css), task)) 7653 return -EINVAL; 7654#else 7655 /* We don't support RT-tasks being in separate groups */ 7656 if (task->sched_class != &fair_sched_class) 7657 return -EINVAL; 7658#endif 7659 } 7660 return 0; 7661} 7662 7663static void cpu_cgroup_attach(struct cgroup_subsys_state *css, 7664 struct cgroup_taskset *tset) 7665{ 7666 struct task_struct *task; 7667 7668 cgroup_taskset_for_each(task, tset) 7669 sched_move_task(task); 7670} 7671 7672static void cpu_cgroup_exit(struct cgroup_subsys_state *css, 7673 struct cgroup_subsys_state *old_css, 7674 struct task_struct *task) 7675{ 7676 /* 7677 * cgroup_exit() is called in the copy_process() failure path. 7678 * Ignore this case since the task hasn't ran yet, this avoids 7679 * trying to poke a half freed task state from generic code. 7680 */ 7681 if (!(task->flags & PF_EXITING)) 7682 return; 7683 7684 sched_move_task(task); 7685} 7686 7687#ifdef CONFIG_FAIR_GROUP_SCHED 7688static int cpu_shares_write_u64(struct cgroup_subsys_state *css, 7689 struct cftype *cftype, u64 shareval) 7690{ 7691 return sched_group_set_shares(css_tg(css), scale_load(shareval)); 7692} 7693 7694static u64 cpu_shares_read_u64(struct cgroup_subsys_state *css, 7695 struct cftype *cft) 7696{ 7697 struct task_group *tg = css_tg(css); 7698 7699 return (u64) scale_load_down(tg->shares); 7700} 7701 7702#ifdef CONFIG_CFS_BANDWIDTH 7703static DEFINE_MUTEX(cfs_constraints_mutex); 7704 7705const u64 max_cfs_quota_period = 1 * NSEC_PER_SEC; /* 1s */ 7706const u64 min_cfs_quota_period = 1 * NSEC_PER_MSEC; /* 1ms */ 7707 7708static int __cfs_schedulable(struct task_group *tg, u64 period, u64 runtime); 7709 7710static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota) 7711{ 7712 int i, ret = 0, runtime_enabled, runtime_was_enabled; 7713 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 7714 7715 if (tg == &root_task_group) 7716 return -EINVAL; 7717 7718 /* 7719 * Ensure we have at some amount of bandwidth every period. This is 7720 * to prevent reaching a state of large arrears when throttled via 7721 * entity_tick() resulting in prolonged exit starvation. 7722 */ 7723 if (quota < min_cfs_quota_period || period < min_cfs_quota_period) 7724 return -EINVAL; 7725 7726 /* 7727 * Likewise, bound things on the otherside by preventing insane quota 7728 * periods. This also allows us to normalize in computing quota 7729 * feasibility. 7730 */ 7731 if (period > max_cfs_quota_period) 7732 return -EINVAL; 7733 7734 mutex_lock(&cfs_constraints_mutex); 7735 ret = __cfs_schedulable(tg, period, quota); 7736 if (ret) 7737 goto out_unlock; 7738 7739 runtime_enabled = quota != RUNTIME_INF; 7740 runtime_was_enabled = cfs_b->quota != RUNTIME_INF; 7741 /* 7742 * If we need to toggle cfs_bandwidth_used, off->on must occur 7743 * before making related changes, and on->off must occur afterwards 7744 */ 7745 if (runtime_enabled && !runtime_was_enabled) 7746 cfs_bandwidth_usage_inc(); 7747 raw_spin_lock_irq(&cfs_b->lock); 7748 cfs_b->period = ns_to_ktime(period); 7749 cfs_b->quota = quota; 7750 7751 __refill_cfs_bandwidth_runtime(cfs_b); 7752 /* restart the period timer (if active) to handle new period expiry */ 7753 if (runtime_enabled && cfs_b->timer_active) { 7754 /* force a reprogram */ 7755 cfs_b->timer_active = 0; 7756 __start_cfs_bandwidth(cfs_b); 7757 } 7758 raw_spin_unlock_irq(&cfs_b->lock); 7759 7760 for_each_possible_cpu(i) { 7761 struct cfs_rq *cfs_rq = tg->cfs_rq[i]; 7762 struct rq *rq = cfs_rq->rq; 7763 7764 raw_spin_lock_irq(&rq->lock); 7765 cfs_rq->runtime_enabled = runtime_enabled; 7766 cfs_rq->runtime_remaining = 0; 7767 7768 if (cfs_rq->throttled) 7769 unthrottle_cfs_rq(cfs_rq); 7770 raw_spin_unlock_irq(&rq->lock); 7771 } 7772 if (runtime_was_enabled && !runtime_enabled) 7773 cfs_bandwidth_usage_dec(); 7774out_unlock: 7775 mutex_unlock(&cfs_constraints_mutex); 7776 7777 return ret; 7778} 7779 7780int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us) 7781{ 7782 u64 quota, period; 7783 7784 period = ktime_to_ns(tg->cfs_bandwidth.period); 7785 if (cfs_quota_us < 0) 7786 quota = RUNTIME_INF; 7787 else 7788 quota = (u64)cfs_quota_us * NSEC_PER_USEC; 7789 7790 return tg_set_cfs_bandwidth(tg, period, quota); 7791} 7792 7793long tg_get_cfs_quota(struct task_group *tg) 7794{ 7795 u64 quota_us; 7796 7797 if (tg->cfs_bandwidth.quota == RUNTIME_INF) 7798 return -1; 7799 7800 quota_us = tg->cfs_bandwidth.quota; 7801 do_div(quota_us, NSEC_PER_USEC); 7802 7803 return quota_us; 7804} 7805 7806int tg_set_cfs_period(struct task_group *tg, long cfs_period_us) 7807{ 7808 u64 quota, period; 7809 7810 period = (u64)cfs_period_us * NSEC_PER_USEC; 7811 quota = tg->cfs_bandwidth.quota; 7812 7813 return tg_set_cfs_bandwidth(tg, period, quota); 7814} 7815 7816long tg_get_cfs_period(struct task_group *tg) 7817{ 7818 u64 cfs_period_us; 7819 7820 cfs_period_us = ktime_to_ns(tg->cfs_bandwidth.period); 7821 do_div(cfs_period_us, NSEC_PER_USEC); 7822 7823 return cfs_period_us; 7824} 7825 7826static s64 cpu_cfs_quota_read_s64(struct cgroup_subsys_state *css, 7827 struct cftype *cft) 7828{ 7829 return tg_get_cfs_quota(css_tg(css)); 7830} 7831 7832static int cpu_cfs_quota_write_s64(struct cgroup_subsys_state *css, 7833 struct cftype *cftype, s64 cfs_quota_us) 7834{ 7835 return tg_set_cfs_quota(css_tg(css), cfs_quota_us); 7836} 7837 7838static u64 cpu_cfs_period_read_u64(struct cgroup_subsys_state *css, 7839 struct cftype *cft) 7840{ 7841 return tg_get_cfs_period(css_tg(css)); 7842} 7843 7844static int cpu_cfs_period_write_u64(struct cgroup_subsys_state *css, 7845 struct cftype *cftype, u64 cfs_period_us) 7846{ 7847 return tg_set_cfs_period(css_tg(css), cfs_period_us); 7848} 7849 7850struct cfs_schedulable_data { 7851 struct task_group *tg; 7852 u64 period, quota; 7853}; 7854 7855/* 7856 * normalize group quota/period to be quota/max_period 7857 * note: units are usecs 7858 */ 7859static u64 normalize_cfs_quota(struct task_group *tg, 7860 struct cfs_schedulable_data *d) 7861{ 7862 u64 quota, period; 7863 7864 if (tg == d->tg) { 7865 period = d->period; 7866 quota = d->quota; 7867 } else { 7868 period = tg_get_cfs_period(tg); 7869 quota = tg_get_cfs_quota(tg); 7870 } 7871 7872 /* note: these should typically be equivalent */ 7873 if (quota == RUNTIME_INF || quota == -1) 7874 return RUNTIME_INF; 7875 7876 return to_ratio(period, quota); 7877} 7878 7879static int tg_cfs_schedulable_down(struct task_group *tg, void *data) 7880{ 7881 struct cfs_schedulable_data *d = data; 7882 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 7883 s64 quota = 0, parent_quota = -1; 7884 7885 if (!tg->parent) { 7886 quota = RUNTIME_INF; 7887 } else { 7888 struct cfs_bandwidth *parent_b = &tg->parent->cfs_bandwidth; 7889 7890 quota = normalize_cfs_quota(tg, d); 7891 parent_quota = parent_b->hierarchal_quota; 7892 7893 /* 7894 * ensure max(child_quota) <= parent_quota, inherit when no 7895 * limit is set 7896 */ 7897 if (quota == RUNTIME_INF) 7898 quota = parent_quota; 7899 else if (parent_quota != RUNTIME_INF && quota > parent_quota) 7900 return -EINVAL; 7901 } 7902 cfs_b->hierarchal_quota = quota; 7903 7904 return 0; 7905} 7906 7907static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota) 7908{ 7909 int ret; 7910 struct cfs_schedulable_data data = { 7911 .tg = tg, 7912 .period = period, 7913 .quota = quota, 7914 }; 7915 7916 if (quota != RUNTIME_INF) { 7917 do_div(data.period, NSEC_PER_USEC); 7918 do_div(data.quota, NSEC_PER_USEC); 7919 } 7920 7921 rcu_read_lock(); 7922 ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data); 7923 rcu_read_unlock(); 7924 7925 return ret; 7926} 7927 7928static int cpu_stats_show(struct seq_file *sf, void *v) 7929{ 7930 struct task_group *tg = css_tg(seq_css(sf)); 7931 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 7932 7933 seq_printf(sf, "nr_periods %d\n", cfs_b->nr_periods); 7934 seq_printf(sf, "nr_throttled %d\n", cfs_b->nr_throttled); 7935 seq_printf(sf, "throttled_time %llu\n", cfs_b->throttled_time); 7936 7937 return 0; 7938} 7939#endif /* CONFIG_CFS_BANDWIDTH */ 7940#endif /* CONFIG_FAIR_GROUP_SCHED */ 7941 7942#ifdef CONFIG_RT_GROUP_SCHED 7943static int cpu_rt_runtime_write(struct cgroup_subsys_state *css, 7944 struct cftype *cft, s64 val) 7945{ 7946 return sched_group_set_rt_runtime(css_tg(css), val); 7947} 7948 7949static s64 cpu_rt_runtime_read(struct cgroup_subsys_state *css, 7950 struct cftype *cft) 7951{ 7952 return sched_group_rt_runtime(css_tg(css)); 7953} 7954 7955static int cpu_rt_period_write_uint(struct cgroup_subsys_state *css, 7956 struct cftype *cftype, u64 rt_period_us) 7957{ 7958 return sched_group_set_rt_period(css_tg(css), rt_period_us); 7959} 7960 7961static u64 cpu_rt_period_read_uint(struct cgroup_subsys_state *css, 7962 struct cftype *cft) 7963{ 7964 return sched_group_rt_period(css_tg(css)); 7965} 7966#endif /* CONFIG_RT_GROUP_SCHED */ 7967 7968static struct cftype cpu_files[] = { 7969#ifdef CONFIG_FAIR_GROUP_SCHED 7970 { 7971 .name = "shares", 7972 .read_u64 = cpu_shares_read_u64, 7973 .write_u64 = cpu_shares_write_u64, 7974 }, 7975#endif 7976#ifdef CONFIG_CFS_BANDWIDTH 7977 { 7978 .name = "cfs_quota_us", 7979 .read_s64 = cpu_cfs_quota_read_s64, 7980 .write_s64 = cpu_cfs_quota_write_s64, 7981 }, 7982 { 7983 .name = "cfs_period_us", 7984 .read_u64 = cpu_cfs_period_read_u64, 7985 .write_u64 = cpu_cfs_period_write_u64, 7986 }, 7987 { 7988 .name = "stat", 7989 .seq_show = cpu_stats_show, 7990 }, 7991#endif 7992#ifdef CONFIG_RT_GROUP_SCHED 7993 { 7994 .name = "rt_runtime_us", 7995 .read_s64 = cpu_rt_runtime_read, 7996 .write_s64 = cpu_rt_runtime_write, 7997 }, 7998 { 7999 .name = "rt_period_us", 8000 .read_u64 = cpu_rt_period_read_uint, 8001 .write_u64 = cpu_rt_period_write_uint, 8002 }, 8003#endif 8004 { } /* terminate */ 8005}; 8006 8007struct cgroup_subsys cpu_cgrp_subsys = { 8008 .css_alloc = cpu_cgroup_css_alloc, 8009 .css_free = cpu_cgroup_css_free, 8010 .css_online = cpu_cgroup_css_online, 8011 .css_offline = cpu_cgroup_css_offline, 8012 .can_attach = cpu_cgroup_can_attach, 8013 .attach = cpu_cgroup_attach, 8014 .exit = cpu_cgroup_exit, 8015 .base_cftypes = cpu_files, 8016 .early_init = 1, 8017}; 8018 8019#endif /* CONFIG_CGROUP_SCHED */ 8020 8021void dump_cpu_task(int cpu) 8022{ 8023 pr_info("Task dump for CPU %d:\n", cpu); 8024 sched_show_task(cpu_curr(cpu)); 8025} 8026