core.c revision 2d3d891d3344159d5b452a645e355bbe29591e8b
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 77#include <asm/switch_to.h> 78#include <asm/tlb.h> 79#include <asm/irq_regs.h> 80#include <asm/mutex.h> 81#ifdef CONFIG_PARAVIRT 82#include <asm/paravirt.h> 83#endif 84 85#include "sched.h" 86#include "../workqueue_internal.h" 87#include "../smpboot.h" 88 89#define CREATE_TRACE_POINTS 90#include <trace/events/sched.h> 91 92void start_bandwidth_timer(struct hrtimer *period_timer, ktime_t period) 93{ 94 unsigned long delta; 95 ktime_t soft, hard, now; 96 97 for (;;) { 98 if (hrtimer_active(period_timer)) 99 break; 100 101 now = hrtimer_cb_get_time(period_timer); 102 hrtimer_forward(period_timer, now, period); 103 104 soft = hrtimer_get_softexpires(period_timer); 105 hard = hrtimer_get_expires(period_timer); 106 delta = ktime_to_ns(ktime_sub(hard, soft)); 107 __hrtimer_start_range_ns(period_timer, soft, delta, 108 HRTIMER_MODE_ABS_PINNED, 0); 109 } 110} 111 112DEFINE_MUTEX(sched_domains_mutex); 113DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); 114 115static void update_rq_clock_task(struct rq *rq, s64 delta); 116 117void update_rq_clock(struct rq *rq) 118{ 119 s64 delta; 120 121 if (rq->skip_clock_update > 0) 122 return; 123 124 delta = sched_clock_cpu(cpu_of(rq)) - rq->clock; 125 rq->clock += delta; 126 update_rq_clock_task(rq, delta); 127} 128 129/* 130 * Debugging: various feature bits 131 */ 132 133#define SCHED_FEAT(name, enabled) \ 134 (1UL << __SCHED_FEAT_##name) * enabled | 135 136const_debug unsigned int sysctl_sched_features = 137#include "features.h" 138 0; 139 140#undef SCHED_FEAT 141 142#ifdef CONFIG_SCHED_DEBUG 143#define SCHED_FEAT(name, enabled) \ 144 #name , 145 146static const char * const sched_feat_names[] = { 147#include "features.h" 148}; 149 150#undef SCHED_FEAT 151 152static int sched_feat_show(struct seq_file *m, void *v) 153{ 154 int i; 155 156 for (i = 0; i < __SCHED_FEAT_NR; i++) { 157 if (!(sysctl_sched_features & (1UL << i))) 158 seq_puts(m, "NO_"); 159 seq_printf(m, "%s ", sched_feat_names[i]); 160 } 161 seq_puts(m, "\n"); 162 163 return 0; 164} 165 166#ifdef HAVE_JUMP_LABEL 167 168#define jump_label_key__true STATIC_KEY_INIT_TRUE 169#define jump_label_key__false STATIC_KEY_INIT_FALSE 170 171#define SCHED_FEAT(name, enabled) \ 172 jump_label_key__##enabled , 173 174struct static_key sched_feat_keys[__SCHED_FEAT_NR] = { 175#include "features.h" 176}; 177 178#undef SCHED_FEAT 179 180static void sched_feat_disable(int i) 181{ 182 if (static_key_enabled(&sched_feat_keys[i])) 183 static_key_slow_dec(&sched_feat_keys[i]); 184} 185 186static void sched_feat_enable(int i) 187{ 188 if (!static_key_enabled(&sched_feat_keys[i])) 189 static_key_slow_inc(&sched_feat_keys[i]); 190} 191#else 192static void sched_feat_disable(int i) { }; 193static void sched_feat_enable(int i) { }; 194#endif /* HAVE_JUMP_LABEL */ 195 196static int sched_feat_set(char *cmp) 197{ 198 int i; 199 int neg = 0; 200 201 if (strncmp(cmp, "NO_", 3) == 0) { 202 neg = 1; 203 cmp += 3; 204 } 205 206 for (i = 0; i < __SCHED_FEAT_NR; i++) { 207 if (strcmp(cmp, sched_feat_names[i]) == 0) { 208 if (neg) { 209 sysctl_sched_features &= ~(1UL << i); 210 sched_feat_disable(i); 211 } else { 212 sysctl_sched_features |= (1UL << i); 213 sched_feat_enable(i); 214 } 215 break; 216 } 217 } 218 219 return i; 220} 221 222static ssize_t 223sched_feat_write(struct file *filp, const char __user *ubuf, 224 size_t cnt, loff_t *ppos) 225{ 226 char buf[64]; 227 char *cmp; 228 int i; 229 230 if (cnt > 63) 231 cnt = 63; 232 233 if (copy_from_user(&buf, ubuf, cnt)) 234 return -EFAULT; 235 236 buf[cnt] = 0; 237 cmp = strstrip(buf); 238 239 i = sched_feat_set(cmp); 240 if (i == __SCHED_FEAT_NR) 241 return -EINVAL; 242 243 *ppos += cnt; 244 245 return cnt; 246} 247 248static int sched_feat_open(struct inode *inode, struct file *filp) 249{ 250 return single_open(filp, sched_feat_show, NULL); 251} 252 253static const struct file_operations sched_feat_fops = { 254 .open = sched_feat_open, 255 .write = sched_feat_write, 256 .read = seq_read, 257 .llseek = seq_lseek, 258 .release = single_release, 259}; 260 261static __init int sched_init_debug(void) 262{ 263 debugfs_create_file("sched_features", 0644, NULL, NULL, 264 &sched_feat_fops); 265 266 return 0; 267} 268late_initcall(sched_init_debug); 269#endif /* CONFIG_SCHED_DEBUG */ 270 271/* 272 * Number of tasks to iterate in a single balance run. 273 * Limited because this is done with IRQs disabled. 274 */ 275const_debug unsigned int sysctl_sched_nr_migrate = 32; 276 277/* 278 * period over which we average the RT time consumption, measured 279 * in ms. 280 * 281 * default: 1s 282 */ 283const_debug unsigned int sysctl_sched_time_avg = MSEC_PER_SEC; 284 285/* 286 * period over which we measure -rt task cpu usage in us. 287 * default: 1s 288 */ 289unsigned int sysctl_sched_rt_period = 1000000; 290 291__read_mostly int scheduler_running; 292 293/* 294 * part of the period that we allow rt tasks to run in us. 295 * default: 0.95s 296 */ 297int sysctl_sched_rt_runtime = 950000; 298 299 300 301/* 302 * __task_rq_lock - lock the rq @p resides on. 303 */ 304static inline struct rq *__task_rq_lock(struct task_struct *p) 305 __acquires(rq->lock) 306{ 307 struct rq *rq; 308 309 lockdep_assert_held(&p->pi_lock); 310 311 for (;;) { 312 rq = task_rq(p); 313 raw_spin_lock(&rq->lock); 314 if (likely(rq == task_rq(p))) 315 return rq; 316 raw_spin_unlock(&rq->lock); 317 } 318} 319 320/* 321 * task_rq_lock - lock p->pi_lock and lock the rq @p resides on. 322 */ 323static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags) 324 __acquires(p->pi_lock) 325 __acquires(rq->lock) 326{ 327 struct rq *rq; 328 329 for (;;) { 330 raw_spin_lock_irqsave(&p->pi_lock, *flags); 331 rq = task_rq(p); 332 raw_spin_lock(&rq->lock); 333 if (likely(rq == task_rq(p))) 334 return rq; 335 raw_spin_unlock(&rq->lock); 336 raw_spin_unlock_irqrestore(&p->pi_lock, *flags); 337 } 338} 339 340static void __task_rq_unlock(struct rq *rq) 341 __releases(rq->lock) 342{ 343 raw_spin_unlock(&rq->lock); 344} 345 346static inline void 347task_rq_unlock(struct rq *rq, struct task_struct *p, unsigned long *flags) 348 __releases(rq->lock) 349 __releases(p->pi_lock) 350{ 351 raw_spin_unlock(&rq->lock); 352 raw_spin_unlock_irqrestore(&p->pi_lock, *flags); 353} 354 355/* 356 * this_rq_lock - lock this runqueue and disable interrupts. 357 */ 358static struct rq *this_rq_lock(void) 359 __acquires(rq->lock) 360{ 361 struct rq *rq; 362 363 local_irq_disable(); 364 rq = this_rq(); 365 raw_spin_lock(&rq->lock); 366 367 return rq; 368} 369 370#ifdef CONFIG_SCHED_HRTICK 371/* 372 * Use HR-timers to deliver accurate preemption points. 373 */ 374 375static void hrtick_clear(struct rq *rq) 376{ 377 if (hrtimer_active(&rq->hrtick_timer)) 378 hrtimer_cancel(&rq->hrtick_timer); 379} 380 381/* 382 * High-resolution timer tick. 383 * Runs from hardirq context with interrupts disabled. 384 */ 385static enum hrtimer_restart hrtick(struct hrtimer *timer) 386{ 387 struct rq *rq = container_of(timer, struct rq, hrtick_timer); 388 389 WARN_ON_ONCE(cpu_of(rq) != smp_processor_id()); 390 391 raw_spin_lock(&rq->lock); 392 update_rq_clock(rq); 393 rq->curr->sched_class->task_tick(rq, rq->curr, 1); 394 raw_spin_unlock(&rq->lock); 395 396 return HRTIMER_NORESTART; 397} 398 399#ifdef CONFIG_SMP 400 401static int __hrtick_restart(struct rq *rq) 402{ 403 struct hrtimer *timer = &rq->hrtick_timer; 404 ktime_t time = hrtimer_get_softexpires(timer); 405 406 return __hrtimer_start_range_ns(timer, time, 0, HRTIMER_MODE_ABS_PINNED, 0); 407} 408 409/* 410 * called from hardirq (IPI) context 411 */ 412static void __hrtick_start(void *arg) 413{ 414 struct rq *rq = arg; 415 416 raw_spin_lock(&rq->lock); 417 __hrtick_restart(rq); 418 rq->hrtick_csd_pending = 0; 419 raw_spin_unlock(&rq->lock); 420} 421 422/* 423 * Called to set the hrtick timer state. 424 * 425 * called with rq->lock held and irqs disabled 426 */ 427void hrtick_start(struct rq *rq, u64 delay) 428{ 429 struct hrtimer *timer = &rq->hrtick_timer; 430 ktime_t time = ktime_add_ns(timer->base->get_time(), delay); 431 432 hrtimer_set_expires(timer, time); 433 434 if (rq == this_rq()) { 435 __hrtick_restart(rq); 436 } else if (!rq->hrtick_csd_pending) { 437 __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd, 0); 438 rq->hrtick_csd_pending = 1; 439 } 440} 441 442static int 443hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu) 444{ 445 int cpu = (int)(long)hcpu; 446 447 switch (action) { 448 case CPU_UP_CANCELED: 449 case CPU_UP_CANCELED_FROZEN: 450 case CPU_DOWN_PREPARE: 451 case CPU_DOWN_PREPARE_FROZEN: 452 case CPU_DEAD: 453 case CPU_DEAD_FROZEN: 454 hrtick_clear(cpu_rq(cpu)); 455 return NOTIFY_OK; 456 } 457 458 return NOTIFY_DONE; 459} 460 461static __init void init_hrtick(void) 462{ 463 hotcpu_notifier(hotplug_hrtick, 0); 464} 465#else 466/* 467 * Called to set the hrtick timer state. 468 * 469 * called with rq->lock held and irqs disabled 470 */ 471void hrtick_start(struct rq *rq, u64 delay) 472{ 473 __hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0, 474 HRTIMER_MODE_REL_PINNED, 0); 475} 476 477static inline void init_hrtick(void) 478{ 479} 480#endif /* CONFIG_SMP */ 481 482static void init_rq_hrtick(struct rq *rq) 483{ 484#ifdef CONFIG_SMP 485 rq->hrtick_csd_pending = 0; 486 487 rq->hrtick_csd.flags = 0; 488 rq->hrtick_csd.func = __hrtick_start; 489 rq->hrtick_csd.info = rq; 490#endif 491 492 hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 493 rq->hrtick_timer.function = hrtick; 494} 495#else /* CONFIG_SCHED_HRTICK */ 496static inline void hrtick_clear(struct rq *rq) 497{ 498} 499 500static inline void init_rq_hrtick(struct rq *rq) 501{ 502} 503 504static inline void init_hrtick(void) 505{ 506} 507#endif /* CONFIG_SCHED_HRTICK */ 508 509/* 510 * resched_task - mark a task 'to be rescheduled now'. 511 * 512 * On UP this means the setting of the need_resched flag, on SMP it 513 * might also involve a cross-CPU call to trigger the scheduler on 514 * the target CPU. 515 */ 516void resched_task(struct task_struct *p) 517{ 518 int cpu; 519 520 lockdep_assert_held(&task_rq(p)->lock); 521 522 if (test_tsk_need_resched(p)) 523 return; 524 525 set_tsk_need_resched(p); 526 527 cpu = task_cpu(p); 528 if (cpu == smp_processor_id()) { 529 set_preempt_need_resched(); 530 return; 531 } 532 533 /* NEED_RESCHED must be visible before we test polling */ 534 smp_mb(); 535 if (!tsk_is_polling(p)) 536 smp_send_reschedule(cpu); 537} 538 539void resched_cpu(int cpu) 540{ 541 struct rq *rq = cpu_rq(cpu); 542 unsigned long flags; 543 544 if (!raw_spin_trylock_irqsave(&rq->lock, flags)) 545 return; 546 resched_task(cpu_curr(cpu)); 547 raw_spin_unlock_irqrestore(&rq->lock, flags); 548} 549 550#ifdef CONFIG_SMP 551#ifdef CONFIG_NO_HZ_COMMON 552/* 553 * In the semi idle case, use the nearest busy cpu for migrating timers 554 * from an idle cpu. This is good for power-savings. 555 * 556 * We don't do similar optimization for completely idle system, as 557 * selecting an idle cpu will add more delays to the timers than intended 558 * (as that cpu's timer base may not be uptodate wrt jiffies etc). 559 */ 560int get_nohz_timer_target(void) 561{ 562 int cpu = smp_processor_id(); 563 int i; 564 struct sched_domain *sd; 565 566 rcu_read_lock(); 567 for_each_domain(cpu, sd) { 568 for_each_cpu(i, sched_domain_span(sd)) { 569 if (!idle_cpu(i)) { 570 cpu = i; 571 goto unlock; 572 } 573 } 574 } 575unlock: 576 rcu_read_unlock(); 577 return cpu; 578} 579/* 580 * When add_timer_on() enqueues a timer into the timer wheel of an 581 * idle CPU then this timer might expire before the next timer event 582 * which is scheduled to wake up that CPU. In case of a completely 583 * idle system the next event might even be infinite time into the 584 * future. wake_up_idle_cpu() ensures that the CPU is woken up and 585 * leaves the inner idle loop so the newly added timer is taken into 586 * account when the CPU goes back to idle and evaluates the timer 587 * wheel for the next timer event. 588 */ 589static void wake_up_idle_cpu(int cpu) 590{ 591 struct rq *rq = cpu_rq(cpu); 592 593 if (cpu == smp_processor_id()) 594 return; 595 596 /* 597 * This is safe, as this function is called with the timer 598 * wheel base lock of (cpu) held. When the CPU is on the way 599 * to idle and has not yet set rq->curr to idle then it will 600 * be serialized on the timer wheel base lock and take the new 601 * timer into account automatically. 602 */ 603 if (rq->curr != rq->idle) 604 return; 605 606 /* 607 * We can set TIF_RESCHED on the idle task of the other CPU 608 * lockless. The worst case is that the other CPU runs the 609 * idle task through an additional NOOP schedule() 610 */ 611 set_tsk_need_resched(rq->idle); 612 613 /* NEED_RESCHED must be visible before we test polling */ 614 smp_mb(); 615 if (!tsk_is_polling(rq->idle)) 616 smp_send_reschedule(cpu); 617} 618 619static bool wake_up_full_nohz_cpu(int cpu) 620{ 621 if (tick_nohz_full_cpu(cpu)) { 622 if (cpu != smp_processor_id() || 623 tick_nohz_tick_stopped()) 624 smp_send_reschedule(cpu); 625 return true; 626 } 627 628 return false; 629} 630 631void wake_up_nohz_cpu(int cpu) 632{ 633 if (!wake_up_full_nohz_cpu(cpu)) 634 wake_up_idle_cpu(cpu); 635} 636 637static inline bool got_nohz_idle_kick(void) 638{ 639 int cpu = smp_processor_id(); 640 641 if (!test_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu))) 642 return false; 643 644 if (idle_cpu(cpu) && !need_resched()) 645 return true; 646 647 /* 648 * We can't run Idle Load Balance on this CPU for this time so we 649 * cancel it and clear NOHZ_BALANCE_KICK 650 */ 651 clear_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu)); 652 return false; 653} 654 655#else /* CONFIG_NO_HZ_COMMON */ 656 657static inline bool got_nohz_idle_kick(void) 658{ 659 return false; 660} 661 662#endif /* CONFIG_NO_HZ_COMMON */ 663 664#ifdef CONFIG_NO_HZ_FULL 665bool sched_can_stop_tick(void) 666{ 667 struct rq *rq; 668 669 rq = this_rq(); 670 671 /* Make sure rq->nr_running update is visible after the IPI */ 672 smp_rmb(); 673 674 /* More than one running task need preemption */ 675 if (rq->nr_running > 1) 676 return false; 677 678 return true; 679} 680#endif /* CONFIG_NO_HZ_FULL */ 681 682void sched_avg_update(struct rq *rq) 683{ 684 s64 period = sched_avg_period(); 685 686 while ((s64)(rq_clock(rq) - rq->age_stamp) > period) { 687 /* 688 * Inline assembly required to prevent the compiler 689 * optimising this loop into a divmod call. 690 * See __iter_div_u64_rem() for another example of this. 691 */ 692 asm("" : "+rm" (rq->age_stamp)); 693 rq->age_stamp += period; 694 rq->rt_avg /= 2; 695 } 696} 697 698#endif /* CONFIG_SMP */ 699 700#if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \ 701 (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH))) 702/* 703 * Iterate task_group tree rooted at *from, calling @down when first entering a 704 * node and @up when leaving it for the final time. 705 * 706 * Caller must hold rcu_lock or sufficient equivalent. 707 */ 708int walk_tg_tree_from(struct task_group *from, 709 tg_visitor down, tg_visitor up, void *data) 710{ 711 struct task_group *parent, *child; 712 int ret; 713 714 parent = from; 715 716down: 717 ret = (*down)(parent, data); 718 if (ret) 719 goto out; 720 list_for_each_entry_rcu(child, &parent->children, siblings) { 721 parent = child; 722 goto down; 723 724up: 725 continue; 726 } 727 ret = (*up)(parent, data); 728 if (ret || parent == from) 729 goto out; 730 731 child = parent; 732 parent = parent->parent; 733 if (parent) 734 goto up; 735out: 736 return ret; 737} 738 739int tg_nop(struct task_group *tg, void *data) 740{ 741 return 0; 742} 743#endif 744 745static void set_load_weight(struct task_struct *p) 746{ 747 int prio = p->static_prio - MAX_RT_PRIO; 748 struct load_weight *load = &p->se.load; 749 750 /* 751 * SCHED_IDLE tasks get minimal weight: 752 */ 753 if (p->policy == SCHED_IDLE) { 754 load->weight = scale_load(WEIGHT_IDLEPRIO); 755 load->inv_weight = WMULT_IDLEPRIO; 756 return; 757 } 758 759 load->weight = scale_load(prio_to_weight[prio]); 760 load->inv_weight = prio_to_wmult[prio]; 761} 762 763static void enqueue_task(struct rq *rq, struct task_struct *p, int flags) 764{ 765 update_rq_clock(rq); 766 sched_info_queued(rq, p); 767 p->sched_class->enqueue_task(rq, p, flags); 768} 769 770static void dequeue_task(struct rq *rq, struct task_struct *p, int flags) 771{ 772 update_rq_clock(rq); 773 sched_info_dequeued(rq, p); 774 p->sched_class->dequeue_task(rq, p, flags); 775} 776 777void activate_task(struct rq *rq, struct task_struct *p, int flags) 778{ 779 if (task_contributes_to_load(p)) 780 rq->nr_uninterruptible--; 781 782 enqueue_task(rq, p, flags); 783} 784 785void deactivate_task(struct rq *rq, struct task_struct *p, int flags) 786{ 787 if (task_contributes_to_load(p)) 788 rq->nr_uninterruptible++; 789 790 dequeue_task(rq, p, flags); 791} 792 793static void update_rq_clock_task(struct rq *rq, s64 delta) 794{ 795/* 796 * In theory, the compile should just see 0 here, and optimize out the call 797 * to sched_rt_avg_update. But I don't trust it... 798 */ 799#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) 800 s64 steal = 0, irq_delta = 0; 801#endif 802#ifdef CONFIG_IRQ_TIME_ACCOUNTING 803 irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time; 804 805 /* 806 * Since irq_time is only updated on {soft,}irq_exit, we might run into 807 * this case when a previous update_rq_clock() happened inside a 808 * {soft,}irq region. 809 * 810 * When this happens, we stop ->clock_task and only update the 811 * prev_irq_time stamp to account for the part that fit, so that a next 812 * update will consume the rest. This ensures ->clock_task is 813 * monotonic. 814 * 815 * It does however cause some slight miss-attribution of {soft,}irq 816 * time, a more accurate solution would be to update the irq_time using 817 * the current rq->clock timestamp, except that would require using 818 * atomic ops. 819 */ 820 if (irq_delta > delta) 821 irq_delta = delta; 822 823 rq->prev_irq_time += irq_delta; 824 delta -= irq_delta; 825#endif 826#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING 827 if (static_key_false((¶virt_steal_rq_enabled))) { 828 u64 st; 829 830 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 st = steal_ticks(steal); 837 steal = st * TICK_NSEC; 838 839 rq->prev_steal_time_rq += steal; 840 841 delta -= steal; 842 } 843#endif 844 845 rq->clock_task += delta; 846 847#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) 848 if ((irq_delta + steal) && sched_feat(NONTASK_POWER)) 849 sched_rt_avg_update(rq, irq_delta + steal); 850#endif 851} 852 853void sched_set_stop_task(int cpu, struct task_struct *stop) 854{ 855 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 }; 856 struct task_struct *old_stop = cpu_rq(cpu)->stop; 857 858 if (stop) { 859 /* 860 * Make it appear like a SCHED_FIFO task, its something 861 * userspace knows about and won't get confused about. 862 * 863 * Also, it will make PI more or less work without too 864 * much confusion -- but then, stop work should not 865 * rely on PI working anyway. 866 */ 867 sched_setscheduler_nocheck(stop, SCHED_FIFO, ¶m); 868 869 stop->sched_class = &stop_sched_class; 870 } 871 872 cpu_rq(cpu)->stop = stop; 873 874 if (old_stop) { 875 /* 876 * Reset it back to a normal scheduling class so that 877 * it can die in pieces. 878 */ 879 old_stop->sched_class = &rt_sched_class; 880 } 881} 882 883/* 884 * __normal_prio - return the priority that is based on the static prio 885 */ 886static inline int __normal_prio(struct task_struct *p) 887{ 888 return p->static_prio; 889} 890 891/* 892 * Calculate the expected normal priority: i.e. priority 893 * without taking RT-inheritance into account. Might be 894 * boosted by interactivity modifiers. Changes upon fork, 895 * setprio syscalls, and whenever the interactivity 896 * estimator recalculates. 897 */ 898static inline int normal_prio(struct task_struct *p) 899{ 900 int prio; 901 902 if (task_has_dl_policy(p)) 903 prio = MAX_DL_PRIO-1; 904 else if (task_has_rt_policy(p)) 905 prio = MAX_RT_PRIO-1 - p->rt_priority; 906 else 907 prio = __normal_prio(p); 908 return prio; 909} 910 911/* 912 * Calculate the current priority, i.e. the priority 913 * taken into account by the scheduler. This value might 914 * be boosted by RT tasks, or might be boosted by 915 * interactivity modifiers. Will be RT if the task got 916 * RT-boosted. If not then it returns p->normal_prio. 917 */ 918static int effective_prio(struct task_struct *p) 919{ 920 p->normal_prio = normal_prio(p); 921 /* 922 * If we are RT tasks or we were boosted to RT priority, 923 * keep the priority unchanged. Otherwise, update priority 924 * to the normal priority: 925 */ 926 if (!rt_prio(p->prio)) 927 return p->normal_prio; 928 return p->prio; 929} 930 931/** 932 * task_curr - is this task currently executing on a CPU? 933 * @p: the task in question. 934 * 935 * Return: 1 if the task is currently executing. 0 otherwise. 936 */ 937inline int task_curr(const struct task_struct *p) 938{ 939 return cpu_curr(task_cpu(p)) == p; 940} 941 942static inline void check_class_changed(struct rq *rq, struct task_struct *p, 943 const struct sched_class *prev_class, 944 int oldprio) 945{ 946 if (prev_class != p->sched_class) { 947 if (prev_class->switched_from) 948 prev_class->switched_from(rq, p); 949 p->sched_class->switched_to(rq, p); 950 } else if (oldprio != p->prio || dl_task(p)) 951 p->sched_class->prio_changed(rq, p, oldprio); 952} 953 954void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags) 955{ 956 const struct sched_class *class; 957 958 if (p->sched_class == rq->curr->sched_class) { 959 rq->curr->sched_class->check_preempt_curr(rq, p, flags); 960 } else { 961 for_each_class(class) { 962 if (class == rq->curr->sched_class) 963 break; 964 if (class == p->sched_class) { 965 resched_task(rq->curr); 966 break; 967 } 968 } 969 } 970 971 /* 972 * A queue event has occurred, and we're going to schedule. In 973 * this case, we can save a useless back to back clock update. 974 */ 975 if (rq->curr->on_rq && test_tsk_need_resched(rq->curr)) 976 rq->skip_clock_update = 1; 977} 978 979#ifdef CONFIG_SMP 980void set_task_cpu(struct task_struct *p, unsigned int new_cpu) 981{ 982#ifdef CONFIG_SCHED_DEBUG 983 /* 984 * We should never call set_task_cpu() on a blocked task, 985 * ttwu() will sort out the placement. 986 */ 987 WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING && 988 !(task_preempt_count(p) & PREEMPT_ACTIVE)); 989 990#ifdef CONFIG_LOCKDEP 991 /* 992 * The caller should hold either p->pi_lock or rq->lock, when changing 993 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks. 994 * 995 * sched_move_task() holds both and thus holding either pins the cgroup, 996 * see task_group(). 997 * 998 * Furthermore, all task_rq users should acquire both locks, see 999 * task_rq_lock(). 1000 */ 1001 WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) || 1002 lockdep_is_held(&task_rq(p)->lock))); 1003#endif 1004#endif 1005 1006 trace_sched_migrate_task(p, new_cpu); 1007 1008 if (task_cpu(p) != new_cpu) { 1009 if (p->sched_class->migrate_task_rq) 1010 p->sched_class->migrate_task_rq(p, new_cpu); 1011 p->se.nr_migrations++; 1012 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, 1, NULL, 0); 1013 } 1014 1015 __set_task_cpu(p, new_cpu); 1016} 1017 1018static void __migrate_swap_task(struct task_struct *p, int cpu) 1019{ 1020 if (p->on_rq) { 1021 struct rq *src_rq, *dst_rq; 1022 1023 src_rq = task_rq(p); 1024 dst_rq = cpu_rq(cpu); 1025 1026 deactivate_task(src_rq, p, 0); 1027 set_task_cpu(p, cpu); 1028 activate_task(dst_rq, p, 0); 1029 check_preempt_curr(dst_rq, p, 0); 1030 } else { 1031 /* 1032 * Task isn't running anymore; make it appear like we migrated 1033 * it before it went to sleep. This means on wakeup we make the 1034 * previous cpu our targer instead of where it really is. 1035 */ 1036 p->wake_cpu = cpu; 1037 } 1038} 1039 1040struct migration_swap_arg { 1041 struct task_struct *src_task, *dst_task; 1042 int src_cpu, dst_cpu; 1043}; 1044 1045static int migrate_swap_stop(void *data) 1046{ 1047 struct migration_swap_arg *arg = data; 1048 struct rq *src_rq, *dst_rq; 1049 int ret = -EAGAIN; 1050 1051 src_rq = cpu_rq(arg->src_cpu); 1052 dst_rq = cpu_rq(arg->dst_cpu); 1053 1054 double_raw_lock(&arg->src_task->pi_lock, 1055 &arg->dst_task->pi_lock); 1056 double_rq_lock(src_rq, dst_rq); 1057 if (task_cpu(arg->dst_task) != arg->dst_cpu) 1058 goto unlock; 1059 1060 if (task_cpu(arg->src_task) != arg->src_cpu) 1061 goto unlock; 1062 1063 if (!cpumask_test_cpu(arg->dst_cpu, tsk_cpus_allowed(arg->src_task))) 1064 goto unlock; 1065 1066 if (!cpumask_test_cpu(arg->src_cpu, tsk_cpus_allowed(arg->dst_task))) 1067 goto unlock; 1068 1069 __migrate_swap_task(arg->src_task, arg->dst_cpu); 1070 __migrate_swap_task(arg->dst_task, arg->src_cpu); 1071 1072 ret = 0; 1073 1074unlock: 1075 double_rq_unlock(src_rq, dst_rq); 1076 raw_spin_unlock(&arg->dst_task->pi_lock); 1077 raw_spin_unlock(&arg->src_task->pi_lock); 1078 1079 return ret; 1080} 1081 1082/* 1083 * Cross migrate two tasks 1084 */ 1085int migrate_swap(struct task_struct *cur, struct task_struct *p) 1086{ 1087 struct migration_swap_arg arg; 1088 int ret = -EINVAL; 1089 1090 arg = (struct migration_swap_arg){ 1091 .src_task = cur, 1092 .src_cpu = task_cpu(cur), 1093 .dst_task = p, 1094 .dst_cpu = task_cpu(p), 1095 }; 1096 1097 if (arg.src_cpu == arg.dst_cpu) 1098 goto out; 1099 1100 /* 1101 * These three tests are all lockless; this is OK since all of them 1102 * will be re-checked with proper locks held further down the line. 1103 */ 1104 if (!cpu_active(arg.src_cpu) || !cpu_active(arg.dst_cpu)) 1105 goto out; 1106 1107 if (!cpumask_test_cpu(arg.dst_cpu, tsk_cpus_allowed(arg.src_task))) 1108 goto out; 1109 1110 if (!cpumask_test_cpu(arg.src_cpu, tsk_cpus_allowed(arg.dst_task))) 1111 goto out; 1112 1113 ret = stop_two_cpus(arg.dst_cpu, arg.src_cpu, migrate_swap_stop, &arg); 1114 1115out: 1116 return ret; 1117} 1118 1119struct migration_arg { 1120 struct task_struct *task; 1121 int dest_cpu; 1122}; 1123 1124static int migration_cpu_stop(void *data); 1125 1126/* 1127 * wait_task_inactive - wait for a thread to unschedule. 1128 * 1129 * If @match_state is nonzero, it's the @p->state value just checked and 1130 * not expected to change. If it changes, i.e. @p might have woken up, 1131 * then return zero. When we succeed in waiting for @p to be off its CPU, 1132 * we return a positive number (its total switch count). If a second call 1133 * a short while later returns the same number, the caller can be sure that 1134 * @p has remained unscheduled the whole time. 1135 * 1136 * The caller must ensure that the task *will* unschedule sometime soon, 1137 * else this function might spin for a *long* time. This function can't 1138 * be called with interrupts off, or it may introduce deadlock with 1139 * smp_call_function() if an IPI is sent by the same process we are 1140 * waiting to become inactive. 1141 */ 1142unsigned long wait_task_inactive(struct task_struct *p, long match_state) 1143{ 1144 unsigned long flags; 1145 int running, on_rq; 1146 unsigned long ncsw; 1147 struct rq *rq; 1148 1149 for (;;) { 1150 /* 1151 * We do the initial early heuristics without holding 1152 * any task-queue locks at all. We'll only try to get 1153 * the runqueue lock when things look like they will 1154 * work out! 1155 */ 1156 rq = task_rq(p); 1157 1158 /* 1159 * If the task is actively running on another CPU 1160 * still, just relax and busy-wait without holding 1161 * any locks. 1162 * 1163 * NOTE! Since we don't hold any locks, it's not 1164 * even sure that "rq" stays as the right runqueue! 1165 * But we don't care, since "task_running()" will 1166 * return false if the runqueue has changed and p 1167 * is actually now running somewhere else! 1168 */ 1169 while (task_running(rq, p)) { 1170 if (match_state && unlikely(p->state != match_state)) 1171 return 0; 1172 cpu_relax(); 1173 } 1174 1175 /* 1176 * Ok, time to look more closely! We need the rq 1177 * lock now, to be *sure*. If we're wrong, we'll 1178 * just go back and repeat. 1179 */ 1180 rq = task_rq_lock(p, &flags); 1181 trace_sched_wait_task(p); 1182 running = task_running(rq, p); 1183 on_rq = p->on_rq; 1184 ncsw = 0; 1185 if (!match_state || p->state == match_state) 1186 ncsw = p->nvcsw | LONG_MIN; /* sets MSB */ 1187 task_rq_unlock(rq, p, &flags); 1188 1189 /* 1190 * If it changed from the expected state, bail out now. 1191 */ 1192 if (unlikely(!ncsw)) 1193 break; 1194 1195 /* 1196 * Was it really running after all now that we 1197 * checked with the proper locks actually held? 1198 * 1199 * Oops. Go back and try again.. 1200 */ 1201 if (unlikely(running)) { 1202 cpu_relax(); 1203 continue; 1204 } 1205 1206 /* 1207 * It's not enough that it's not actively running, 1208 * it must be off the runqueue _entirely_, and not 1209 * preempted! 1210 * 1211 * So if it was still runnable (but just not actively 1212 * running right now), it's preempted, and we should 1213 * yield - it could be a while. 1214 */ 1215 if (unlikely(on_rq)) { 1216 ktime_t to = ktime_set(0, NSEC_PER_SEC/HZ); 1217 1218 set_current_state(TASK_UNINTERRUPTIBLE); 1219 schedule_hrtimeout(&to, HRTIMER_MODE_REL); 1220 continue; 1221 } 1222 1223 /* 1224 * Ahh, all good. It wasn't running, and it wasn't 1225 * runnable, which means that it will never become 1226 * running in the future either. We're all done! 1227 */ 1228 break; 1229 } 1230 1231 return ncsw; 1232} 1233 1234/*** 1235 * kick_process - kick a running thread to enter/exit the kernel 1236 * @p: the to-be-kicked thread 1237 * 1238 * Cause a process which is running on another CPU to enter 1239 * kernel-mode, without any delay. (to get signals handled.) 1240 * 1241 * NOTE: this function doesn't have to take the runqueue lock, 1242 * because all it wants to ensure is that the remote task enters 1243 * the kernel. If the IPI races and the task has been migrated 1244 * to another CPU then no harm is done and the purpose has been 1245 * achieved as well. 1246 */ 1247void kick_process(struct task_struct *p) 1248{ 1249 int cpu; 1250 1251 preempt_disable(); 1252 cpu = task_cpu(p); 1253 if ((cpu != smp_processor_id()) && task_curr(p)) 1254 smp_send_reschedule(cpu); 1255 preempt_enable(); 1256} 1257EXPORT_SYMBOL_GPL(kick_process); 1258#endif /* CONFIG_SMP */ 1259 1260#ifdef CONFIG_SMP 1261/* 1262 * ->cpus_allowed is protected by both rq->lock and p->pi_lock 1263 */ 1264static int select_fallback_rq(int cpu, struct task_struct *p) 1265{ 1266 int nid = cpu_to_node(cpu); 1267 const struct cpumask *nodemask = NULL; 1268 enum { cpuset, possible, fail } state = cpuset; 1269 int dest_cpu; 1270 1271 /* 1272 * If the node that the cpu is on has been offlined, cpu_to_node() 1273 * will return -1. There is no cpu on the node, and we should 1274 * select the cpu on the other node. 1275 */ 1276 if (nid != -1) { 1277 nodemask = cpumask_of_node(nid); 1278 1279 /* Look for allowed, online CPU in same node. */ 1280 for_each_cpu(dest_cpu, nodemask) { 1281 if (!cpu_online(dest_cpu)) 1282 continue; 1283 if (!cpu_active(dest_cpu)) 1284 continue; 1285 if (cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) 1286 return dest_cpu; 1287 } 1288 } 1289 1290 for (;;) { 1291 /* Any allowed, online CPU? */ 1292 for_each_cpu(dest_cpu, tsk_cpus_allowed(p)) { 1293 if (!cpu_online(dest_cpu)) 1294 continue; 1295 if (!cpu_active(dest_cpu)) 1296 continue; 1297 goto out; 1298 } 1299 1300 switch (state) { 1301 case cpuset: 1302 /* No more Mr. Nice Guy. */ 1303 cpuset_cpus_allowed_fallback(p); 1304 state = possible; 1305 break; 1306 1307 case possible: 1308 do_set_cpus_allowed(p, cpu_possible_mask); 1309 state = fail; 1310 break; 1311 1312 case fail: 1313 BUG(); 1314 break; 1315 } 1316 } 1317 1318out: 1319 if (state != cpuset) { 1320 /* 1321 * Don't tell them about moving exiting tasks or 1322 * kernel threads (both mm NULL), since they never 1323 * leave kernel. 1324 */ 1325 if (p->mm && printk_ratelimit()) { 1326 printk_sched("process %d (%s) no longer affine to cpu%d\n", 1327 task_pid_nr(p), p->comm, cpu); 1328 } 1329 } 1330 1331 return dest_cpu; 1332} 1333 1334/* 1335 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable. 1336 */ 1337static inline 1338int select_task_rq(struct task_struct *p, int cpu, int sd_flags, int wake_flags) 1339{ 1340 cpu = p->sched_class->select_task_rq(p, cpu, sd_flags, wake_flags); 1341 1342 /* 1343 * In order not to call set_task_cpu() on a blocking task we need 1344 * to rely on ttwu() to place the task on a valid ->cpus_allowed 1345 * cpu. 1346 * 1347 * Since this is common to all placement strategies, this lives here. 1348 * 1349 * [ this allows ->select_task() to simply return task_cpu(p) and 1350 * not worry about this generic constraint ] 1351 */ 1352 if (unlikely(!cpumask_test_cpu(cpu, tsk_cpus_allowed(p)) || 1353 !cpu_online(cpu))) 1354 cpu = select_fallback_rq(task_cpu(p), p); 1355 1356 return cpu; 1357} 1358 1359static void update_avg(u64 *avg, u64 sample) 1360{ 1361 s64 diff = sample - *avg; 1362 *avg += diff >> 3; 1363} 1364#endif 1365 1366static void 1367ttwu_stat(struct task_struct *p, int cpu, int wake_flags) 1368{ 1369#ifdef CONFIG_SCHEDSTATS 1370 struct rq *rq = this_rq(); 1371 1372#ifdef CONFIG_SMP 1373 int this_cpu = smp_processor_id(); 1374 1375 if (cpu == this_cpu) { 1376 schedstat_inc(rq, ttwu_local); 1377 schedstat_inc(p, se.statistics.nr_wakeups_local); 1378 } else { 1379 struct sched_domain *sd; 1380 1381 schedstat_inc(p, se.statistics.nr_wakeups_remote); 1382 rcu_read_lock(); 1383 for_each_domain(this_cpu, sd) { 1384 if (cpumask_test_cpu(cpu, sched_domain_span(sd))) { 1385 schedstat_inc(sd, ttwu_wake_remote); 1386 break; 1387 } 1388 } 1389 rcu_read_unlock(); 1390 } 1391 1392 if (wake_flags & WF_MIGRATED) 1393 schedstat_inc(p, se.statistics.nr_wakeups_migrate); 1394 1395#endif /* CONFIG_SMP */ 1396 1397 schedstat_inc(rq, ttwu_count); 1398 schedstat_inc(p, se.statistics.nr_wakeups); 1399 1400 if (wake_flags & WF_SYNC) 1401 schedstat_inc(p, se.statistics.nr_wakeups_sync); 1402 1403#endif /* CONFIG_SCHEDSTATS */ 1404} 1405 1406static void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags) 1407{ 1408 activate_task(rq, p, en_flags); 1409 p->on_rq = 1; 1410 1411 /* if a worker is waking up, notify workqueue */ 1412 if (p->flags & PF_WQ_WORKER) 1413 wq_worker_waking_up(p, cpu_of(rq)); 1414} 1415 1416/* 1417 * Mark the task runnable and perform wakeup-preemption. 1418 */ 1419static void 1420ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags) 1421{ 1422 check_preempt_curr(rq, p, wake_flags); 1423 trace_sched_wakeup(p, true); 1424 1425 p->state = TASK_RUNNING; 1426#ifdef CONFIG_SMP 1427 if (p->sched_class->task_woken) 1428 p->sched_class->task_woken(rq, p); 1429 1430 if (rq->idle_stamp) { 1431 u64 delta = rq_clock(rq) - rq->idle_stamp; 1432 u64 max = 2*rq->max_idle_balance_cost; 1433 1434 update_avg(&rq->avg_idle, delta); 1435 1436 if (rq->avg_idle > max) 1437 rq->avg_idle = max; 1438 1439 rq->idle_stamp = 0; 1440 } 1441#endif 1442} 1443 1444static void 1445ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags) 1446{ 1447#ifdef CONFIG_SMP 1448 if (p->sched_contributes_to_load) 1449 rq->nr_uninterruptible--; 1450#endif 1451 1452 ttwu_activate(rq, p, ENQUEUE_WAKEUP | ENQUEUE_WAKING); 1453 ttwu_do_wakeup(rq, p, wake_flags); 1454} 1455 1456/* 1457 * Called in case the task @p isn't fully descheduled from its runqueue, 1458 * in this case we must do a remote wakeup. Its a 'light' wakeup though, 1459 * since all we need to do is flip p->state to TASK_RUNNING, since 1460 * the task is still ->on_rq. 1461 */ 1462static int ttwu_remote(struct task_struct *p, int wake_flags) 1463{ 1464 struct rq *rq; 1465 int ret = 0; 1466 1467 rq = __task_rq_lock(p); 1468 if (p->on_rq) { 1469 /* check_preempt_curr() may use rq clock */ 1470 update_rq_clock(rq); 1471 ttwu_do_wakeup(rq, p, wake_flags); 1472 ret = 1; 1473 } 1474 __task_rq_unlock(rq); 1475 1476 return ret; 1477} 1478 1479#ifdef CONFIG_SMP 1480static void sched_ttwu_pending(void) 1481{ 1482 struct rq *rq = this_rq(); 1483 struct llist_node *llist = llist_del_all(&rq->wake_list); 1484 struct task_struct *p; 1485 1486 raw_spin_lock(&rq->lock); 1487 1488 while (llist) { 1489 p = llist_entry(llist, struct task_struct, wake_entry); 1490 llist = llist_next(llist); 1491 ttwu_do_activate(rq, p, 0); 1492 } 1493 1494 raw_spin_unlock(&rq->lock); 1495} 1496 1497void scheduler_ipi(void) 1498{ 1499 /* 1500 * Fold TIF_NEED_RESCHED into the preempt_count; anybody setting 1501 * TIF_NEED_RESCHED remotely (for the first time) will also send 1502 * this IPI. 1503 */ 1504 if (tif_need_resched()) 1505 set_preempt_need_resched(); 1506 1507 if (llist_empty(&this_rq()->wake_list) 1508 && !tick_nohz_full_cpu(smp_processor_id()) 1509 && !got_nohz_idle_kick()) 1510 return; 1511 1512 /* 1513 * Not all reschedule IPI handlers call irq_enter/irq_exit, since 1514 * traditionally all their work was done from the interrupt return 1515 * path. Now that we actually do some work, we need to make sure 1516 * we do call them. 1517 * 1518 * Some archs already do call them, luckily irq_enter/exit nest 1519 * properly. 1520 * 1521 * Arguably we should visit all archs and update all handlers, 1522 * however a fair share of IPIs are still resched only so this would 1523 * somewhat pessimize the simple resched case. 1524 */ 1525 irq_enter(); 1526 tick_nohz_full_check(); 1527 sched_ttwu_pending(); 1528 1529 /* 1530 * Check if someone kicked us for doing the nohz idle load balance. 1531 */ 1532 if (unlikely(got_nohz_idle_kick())) { 1533 this_rq()->idle_balance = 1; 1534 raise_softirq_irqoff(SCHED_SOFTIRQ); 1535 } 1536 irq_exit(); 1537} 1538 1539static void ttwu_queue_remote(struct task_struct *p, int cpu) 1540{ 1541 if (llist_add(&p->wake_entry, &cpu_rq(cpu)->wake_list)) 1542 smp_send_reschedule(cpu); 1543} 1544 1545bool cpus_share_cache(int this_cpu, int that_cpu) 1546{ 1547 return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu); 1548} 1549#endif /* CONFIG_SMP */ 1550 1551static void ttwu_queue(struct task_struct *p, int cpu) 1552{ 1553 struct rq *rq = cpu_rq(cpu); 1554 1555#if defined(CONFIG_SMP) 1556 if (sched_feat(TTWU_QUEUE) && !cpus_share_cache(smp_processor_id(), cpu)) { 1557 sched_clock_cpu(cpu); /* sync clocks x-cpu */ 1558 ttwu_queue_remote(p, cpu); 1559 return; 1560 } 1561#endif 1562 1563 raw_spin_lock(&rq->lock); 1564 ttwu_do_activate(rq, p, 0); 1565 raw_spin_unlock(&rq->lock); 1566} 1567 1568/** 1569 * try_to_wake_up - wake up a thread 1570 * @p: the thread to be awakened 1571 * @state: the mask of task states that can be woken 1572 * @wake_flags: wake modifier flags (WF_*) 1573 * 1574 * Put it on the run-queue if it's not already there. The "current" 1575 * thread is always on the run-queue (except when the actual 1576 * re-schedule is in progress), and as such you're allowed to do 1577 * the simpler "current->state = TASK_RUNNING" to mark yourself 1578 * runnable without the overhead of this. 1579 * 1580 * Return: %true if @p was woken up, %false if it was already running. 1581 * or @state didn't match @p's state. 1582 */ 1583static int 1584try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) 1585{ 1586 unsigned long flags; 1587 int cpu, success = 0; 1588 1589 /* 1590 * If we are going to wake up a thread waiting for CONDITION we 1591 * need to ensure that CONDITION=1 done by the caller can not be 1592 * reordered with p->state check below. This pairs with mb() in 1593 * set_current_state() the waiting thread does. 1594 */ 1595 smp_mb__before_spinlock(); 1596 raw_spin_lock_irqsave(&p->pi_lock, flags); 1597 if (!(p->state & state)) 1598 goto out; 1599 1600 success = 1; /* we're going to change ->state */ 1601 cpu = task_cpu(p); 1602 1603 if (p->on_rq && ttwu_remote(p, wake_flags)) 1604 goto stat; 1605 1606#ifdef CONFIG_SMP 1607 /* 1608 * If the owning (remote) cpu is still in the middle of schedule() with 1609 * this task as prev, wait until its done referencing the task. 1610 */ 1611 while (p->on_cpu) 1612 cpu_relax(); 1613 /* 1614 * Pairs with the smp_wmb() in finish_lock_switch(). 1615 */ 1616 smp_rmb(); 1617 1618 p->sched_contributes_to_load = !!task_contributes_to_load(p); 1619 p->state = TASK_WAKING; 1620 1621 if (p->sched_class->task_waking) 1622 p->sched_class->task_waking(p); 1623 1624 cpu = select_task_rq(p, p->wake_cpu, SD_BALANCE_WAKE, wake_flags); 1625 if (task_cpu(p) != cpu) { 1626 wake_flags |= WF_MIGRATED; 1627 set_task_cpu(p, cpu); 1628 } 1629#endif /* CONFIG_SMP */ 1630 1631 ttwu_queue(p, cpu); 1632stat: 1633 ttwu_stat(p, cpu, wake_flags); 1634out: 1635 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 1636 1637 return success; 1638} 1639 1640/** 1641 * try_to_wake_up_local - try to wake up a local task with rq lock held 1642 * @p: the thread to be awakened 1643 * 1644 * Put @p on the run-queue if it's not already there. The caller must 1645 * ensure that this_rq() is locked, @p is bound to this_rq() and not 1646 * the current task. 1647 */ 1648static void try_to_wake_up_local(struct task_struct *p) 1649{ 1650 struct rq *rq = task_rq(p); 1651 1652 if (WARN_ON_ONCE(rq != this_rq()) || 1653 WARN_ON_ONCE(p == current)) 1654 return; 1655 1656 lockdep_assert_held(&rq->lock); 1657 1658 if (!raw_spin_trylock(&p->pi_lock)) { 1659 raw_spin_unlock(&rq->lock); 1660 raw_spin_lock(&p->pi_lock); 1661 raw_spin_lock(&rq->lock); 1662 } 1663 1664 if (!(p->state & TASK_NORMAL)) 1665 goto out; 1666 1667 if (!p->on_rq) 1668 ttwu_activate(rq, p, ENQUEUE_WAKEUP); 1669 1670 ttwu_do_wakeup(rq, p, 0); 1671 ttwu_stat(p, smp_processor_id(), 0); 1672out: 1673 raw_spin_unlock(&p->pi_lock); 1674} 1675 1676/** 1677 * wake_up_process - Wake up a specific process 1678 * @p: The process to be woken up. 1679 * 1680 * Attempt to wake up the nominated process and move it to the set of runnable 1681 * processes. 1682 * 1683 * Return: 1 if the process was woken up, 0 if it was already running. 1684 * 1685 * It may be assumed that this function implies a write memory barrier before 1686 * changing the task state if and only if any tasks are woken up. 1687 */ 1688int wake_up_process(struct task_struct *p) 1689{ 1690 WARN_ON(task_is_stopped_or_traced(p)); 1691 return try_to_wake_up(p, TASK_NORMAL, 0); 1692} 1693EXPORT_SYMBOL(wake_up_process); 1694 1695int wake_up_state(struct task_struct *p, unsigned int state) 1696{ 1697 return try_to_wake_up(p, state, 0); 1698} 1699 1700/* 1701 * Perform scheduler related setup for a newly forked process p. 1702 * p is forked by current. 1703 * 1704 * __sched_fork() is basic setup used by init_idle() too: 1705 */ 1706static void __sched_fork(unsigned long clone_flags, struct task_struct *p) 1707{ 1708 p->on_rq = 0; 1709 1710 p->se.on_rq = 0; 1711 p->se.exec_start = 0; 1712 p->se.sum_exec_runtime = 0; 1713 p->se.prev_sum_exec_runtime = 0; 1714 p->se.nr_migrations = 0; 1715 p->se.vruntime = 0; 1716 INIT_LIST_HEAD(&p->se.group_node); 1717 1718#ifdef CONFIG_SCHEDSTATS 1719 memset(&p->se.statistics, 0, sizeof(p->se.statistics)); 1720#endif 1721 1722 RB_CLEAR_NODE(&p->dl.rb_node); 1723 hrtimer_init(&p->dl.dl_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 1724 p->dl.dl_runtime = p->dl.runtime = 0; 1725 p->dl.dl_deadline = p->dl.deadline = 0; 1726 p->dl.dl_period = 0; 1727 p->dl.flags = 0; 1728 1729 INIT_LIST_HEAD(&p->rt.run_list); 1730 1731#ifdef CONFIG_PREEMPT_NOTIFIERS 1732 INIT_HLIST_HEAD(&p->preempt_notifiers); 1733#endif 1734 1735#ifdef CONFIG_NUMA_BALANCING 1736 if (p->mm && atomic_read(&p->mm->mm_users) == 1) { 1737 p->mm->numa_next_scan = jiffies + msecs_to_jiffies(sysctl_numa_balancing_scan_delay); 1738 p->mm->numa_scan_seq = 0; 1739 } 1740 1741 if (clone_flags & CLONE_VM) 1742 p->numa_preferred_nid = current->numa_preferred_nid; 1743 else 1744 p->numa_preferred_nid = -1; 1745 1746 p->node_stamp = 0ULL; 1747 p->numa_scan_seq = p->mm ? p->mm->numa_scan_seq : 0; 1748 p->numa_scan_period = sysctl_numa_balancing_scan_delay; 1749 p->numa_work.next = &p->numa_work; 1750 p->numa_faults = NULL; 1751 p->numa_faults_buffer = NULL; 1752 1753 INIT_LIST_HEAD(&p->numa_entry); 1754 p->numa_group = NULL; 1755#endif /* CONFIG_NUMA_BALANCING */ 1756} 1757 1758#ifdef CONFIG_NUMA_BALANCING 1759#ifdef CONFIG_SCHED_DEBUG 1760void set_numabalancing_state(bool enabled) 1761{ 1762 if (enabled) 1763 sched_feat_set("NUMA"); 1764 else 1765 sched_feat_set("NO_NUMA"); 1766} 1767#else 1768__read_mostly bool numabalancing_enabled; 1769 1770void set_numabalancing_state(bool enabled) 1771{ 1772 numabalancing_enabled = enabled; 1773} 1774#endif /* CONFIG_SCHED_DEBUG */ 1775#endif /* CONFIG_NUMA_BALANCING */ 1776 1777/* 1778 * fork()/clone()-time setup: 1779 */ 1780int sched_fork(unsigned long clone_flags, struct task_struct *p) 1781{ 1782 unsigned long flags; 1783 int cpu = get_cpu(); 1784 1785 __sched_fork(clone_flags, p); 1786 /* 1787 * We mark the process as running here. This guarantees that 1788 * nobody will actually run it, and a signal or other external 1789 * event cannot wake it up and insert it on the runqueue either. 1790 */ 1791 p->state = TASK_RUNNING; 1792 1793 /* 1794 * Make sure we do not leak PI boosting priority to the child. 1795 */ 1796 p->prio = current->normal_prio; 1797 1798 /* 1799 * Revert to default priority/policy on fork if requested. 1800 */ 1801 if (unlikely(p->sched_reset_on_fork)) { 1802 if (task_has_dl_policy(p) || task_has_rt_policy(p)) { 1803 p->policy = SCHED_NORMAL; 1804 p->static_prio = NICE_TO_PRIO(0); 1805 p->rt_priority = 0; 1806 } else if (PRIO_TO_NICE(p->static_prio) < 0) 1807 p->static_prio = NICE_TO_PRIO(0); 1808 1809 p->prio = p->normal_prio = __normal_prio(p); 1810 set_load_weight(p); 1811 1812 /* 1813 * We don't need the reset flag anymore after the fork. It has 1814 * fulfilled its duty: 1815 */ 1816 p->sched_reset_on_fork = 0; 1817 } 1818 1819 if (dl_prio(p->prio)) { 1820 put_cpu(); 1821 return -EAGAIN; 1822 } else if (rt_prio(p->prio)) { 1823 p->sched_class = &rt_sched_class; 1824 } else { 1825 p->sched_class = &fair_sched_class; 1826 } 1827 1828 if (p->sched_class->task_fork) 1829 p->sched_class->task_fork(p); 1830 1831 /* 1832 * The child is not yet in the pid-hash so no cgroup attach races, 1833 * and the cgroup is pinned to this child due to cgroup_fork() 1834 * is ran before sched_fork(). 1835 * 1836 * Silence PROVE_RCU. 1837 */ 1838 raw_spin_lock_irqsave(&p->pi_lock, flags); 1839 set_task_cpu(p, cpu); 1840 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 1841 1842#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) 1843 if (likely(sched_info_on())) 1844 memset(&p->sched_info, 0, sizeof(p->sched_info)); 1845#endif 1846#if defined(CONFIG_SMP) 1847 p->on_cpu = 0; 1848#endif 1849 init_task_preempt_count(p); 1850#ifdef CONFIG_SMP 1851 plist_node_init(&p->pushable_tasks, MAX_PRIO); 1852 RB_CLEAR_NODE(&p->pushable_dl_tasks); 1853#endif 1854 1855 put_cpu(); 1856 return 0; 1857} 1858 1859/* 1860 * wake_up_new_task - wake up a newly created task for the first time. 1861 * 1862 * This function will do some initial scheduler statistics housekeeping 1863 * that must be done for every newly created context, then puts the task 1864 * on the runqueue and wakes it. 1865 */ 1866void wake_up_new_task(struct task_struct *p) 1867{ 1868 unsigned long flags; 1869 struct rq *rq; 1870 1871 raw_spin_lock_irqsave(&p->pi_lock, flags); 1872#ifdef CONFIG_SMP 1873 /* 1874 * Fork balancing, do it here and not earlier because: 1875 * - cpus_allowed can change in the fork path 1876 * - any previously selected cpu might disappear through hotplug 1877 */ 1878 set_task_cpu(p, select_task_rq(p, task_cpu(p), SD_BALANCE_FORK, 0)); 1879#endif 1880 1881 /* Initialize new task's runnable average */ 1882 init_task_runnable_average(p); 1883 rq = __task_rq_lock(p); 1884 activate_task(rq, p, 0); 1885 p->on_rq = 1; 1886 trace_sched_wakeup_new(p, true); 1887 check_preempt_curr(rq, p, WF_FORK); 1888#ifdef CONFIG_SMP 1889 if (p->sched_class->task_woken) 1890 p->sched_class->task_woken(rq, p); 1891#endif 1892 task_rq_unlock(rq, p, &flags); 1893} 1894 1895#ifdef CONFIG_PREEMPT_NOTIFIERS 1896 1897/** 1898 * preempt_notifier_register - tell me when current is being preempted & rescheduled 1899 * @notifier: notifier struct to register 1900 */ 1901void preempt_notifier_register(struct preempt_notifier *notifier) 1902{ 1903 hlist_add_head(¬ifier->link, ¤t->preempt_notifiers); 1904} 1905EXPORT_SYMBOL_GPL(preempt_notifier_register); 1906 1907/** 1908 * preempt_notifier_unregister - no longer interested in preemption notifications 1909 * @notifier: notifier struct to unregister 1910 * 1911 * This is safe to call from within a preemption notifier. 1912 */ 1913void preempt_notifier_unregister(struct preempt_notifier *notifier) 1914{ 1915 hlist_del(¬ifier->link); 1916} 1917EXPORT_SYMBOL_GPL(preempt_notifier_unregister); 1918 1919static void fire_sched_in_preempt_notifiers(struct task_struct *curr) 1920{ 1921 struct preempt_notifier *notifier; 1922 1923 hlist_for_each_entry(notifier, &curr->preempt_notifiers, link) 1924 notifier->ops->sched_in(notifier, raw_smp_processor_id()); 1925} 1926 1927static void 1928fire_sched_out_preempt_notifiers(struct task_struct *curr, 1929 struct task_struct *next) 1930{ 1931 struct preempt_notifier *notifier; 1932 1933 hlist_for_each_entry(notifier, &curr->preempt_notifiers, link) 1934 notifier->ops->sched_out(notifier, next); 1935} 1936 1937#else /* !CONFIG_PREEMPT_NOTIFIERS */ 1938 1939static void fire_sched_in_preempt_notifiers(struct task_struct *curr) 1940{ 1941} 1942 1943static void 1944fire_sched_out_preempt_notifiers(struct task_struct *curr, 1945 struct task_struct *next) 1946{ 1947} 1948 1949#endif /* CONFIG_PREEMPT_NOTIFIERS */ 1950 1951/** 1952 * prepare_task_switch - prepare to switch tasks 1953 * @rq: the runqueue preparing to switch 1954 * @prev: the current task that is being switched out 1955 * @next: the task we are going to switch to. 1956 * 1957 * This is called with the rq lock held and interrupts off. It must 1958 * be paired with a subsequent finish_task_switch after the context 1959 * switch. 1960 * 1961 * prepare_task_switch sets up locking and calls architecture specific 1962 * hooks. 1963 */ 1964static inline void 1965prepare_task_switch(struct rq *rq, struct task_struct *prev, 1966 struct task_struct *next) 1967{ 1968 trace_sched_switch(prev, next); 1969 sched_info_switch(rq, prev, next); 1970 perf_event_task_sched_out(prev, next); 1971 fire_sched_out_preempt_notifiers(prev, next); 1972 prepare_lock_switch(rq, next); 1973 prepare_arch_switch(next); 1974} 1975 1976/** 1977 * finish_task_switch - clean up after a task-switch 1978 * @rq: runqueue associated with task-switch 1979 * @prev: the thread we just switched away from. 1980 * 1981 * finish_task_switch must be called after the context switch, paired 1982 * with a prepare_task_switch call before the context switch. 1983 * finish_task_switch will reconcile locking set up by prepare_task_switch, 1984 * and do any other architecture-specific cleanup actions. 1985 * 1986 * Note that we may have delayed dropping an mm in context_switch(). If 1987 * so, we finish that here outside of the runqueue lock. (Doing it 1988 * with the lock held can cause deadlocks; see schedule() for 1989 * details.) 1990 */ 1991static void finish_task_switch(struct rq *rq, struct task_struct *prev) 1992 __releases(rq->lock) 1993{ 1994 struct mm_struct *mm = rq->prev_mm; 1995 long prev_state; 1996 1997 rq->prev_mm = NULL; 1998 1999 /* 2000 * A task struct has one reference for the use as "current". 2001 * If a task dies, then it sets TASK_DEAD in tsk->state and calls 2002 * schedule one last time. The schedule call will never return, and 2003 * the scheduled task must drop that reference. 2004 * The test for TASK_DEAD must occur while the runqueue locks are 2005 * still held, otherwise prev could be scheduled on another cpu, die 2006 * there before we look at prev->state, and then the reference would 2007 * be dropped twice. 2008 * Manfred Spraul <manfred@colorfullife.com> 2009 */ 2010 prev_state = prev->state; 2011 vtime_task_switch(prev); 2012 finish_arch_switch(prev); 2013 perf_event_task_sched_in(prev, current); 2014 finish_lock_switch(rq, prev); 2015 finish_arch_post_lock_switch(); 2016 2017 fire_sched_in_preempt_notifiers(current); 2018 if (mm) 2019 mmdrop(mm); 2020 if (unlikely(prev_state == TASK_DEAD)) { 2021 task_numa_free(prev); 2022 2023 if (prev->sched_class->task_dead) 2024 prev->sched_class->task_dead(prev); 2025 2026 /* 2027 * Remove function-return probe instances associated with this 2028 * task and put them back on the free list. 2029 */ 2030 kprobe_flush_task(prev); 2031 put_task_struct(prev); 2032 } 2033 2034 tick_nohz_task_switch(current); 2035} 2036 2037#ifdef CONFIG_SMP 2038 2039/* assumes rq->lock is held */ 2040static inline void pre_schedule(struct rq *rq, struct task_struct *prev) 2041{ 2042 if (prev->sched_class->pre_schedule) 2043 prev->sched_class->pre_schedule(rq, prev); 2044} 2045 2046/* rq->lock is NOT held, but preemption is disabled */ 2047static inline void post_schedule(struct rq *rq) 2048{ 2049 if (rq->post_schedule) { 2050 unsigned long flags; 2051 2052 raw_spin_lock_irqsave(&rq->lock, flags); 2053 if (rq->curr->sched_class->post_schedule) 2054 rq->curr->sched_class->post_schedule(rq); 2055 raw_spin_unlock_irqrestore(&rq->lock, flags); 2056 2057 rq->post_schedule = 0; 2058 } 2059} 2060 2061#else 2062 2063static inline void pre_schedule(struct rq *rq, struct task_struct *p) 2064{ 2065} 2066 2067static inline void post_schedule(struct rq *rq) 2068{ 2069} 2070 2071#endif 2072 2073/** 2074 * schedule_tail - first thing a freshly forked thread must call. 2075 * @prev: the thread we just switched away from. 2076 */ 2077asmlinkage void schedule_tail(struct task_struct *prev) 2078 __releases(rq->lock) 2079{ 2080 struct rq *rq = this_rq(); 2081 2082 finish_task_switch(rq, prev); 2083 2084 /* 2085 * FIXME: do we need to worry about rq being invalidated by the 2086 * task_switch? 2087 */ 2088 post_schedule(rq); 2089 2090#ifdef __ARCH_WANT_UNLOCKED_CTXSW 2091 /* In this case, finish_task_switch does not reenable preemption */ 2092 preempt_enable(); 2093#endif 2094 if (current->set_child_tid) 2095 put_user(task_pid_vnr(current), current->set_child_tid); 2096} 2097 2098/* 2099 * context_switch - switch to the new MM and the new 2100 * thread's register state. 2101 */ 2102static inline void 2103context_switch(struct rq *rq, struct task_struct *prev, 2104 struct task_struct *next) 2105{ 2106 struct mm_struct *mm, *oldmm; 2107 2108 prepare_task_switch(rq, prev, next); 2109 2110 mm = next->mm; 2111 oldmm = prev->active_mm; 2112 /* 2113 * For paravirt, this is coupled with an exit in switch_to to 2114 * combine the page table reload and the switch backend into 2115 * one hypercall. 2116 */ 2117 arch_start_context_switch(prev); 2118 2119 if (!mm) { 2120 next->active_mm = oldmm; 2121 atomic_inc(&oldmm->mm_count); 2122 enter_lazy_tlb(oldmm, next); 2123 } else 2124 switch_mm(oldmm, mm, next); 2125 2126 if (!prev->mm) { 2127 prev->active_mm = NULL; 2128 rq->prev_mm = oldmm; 2129 } 2130 /* 2131 * Since the runqueue lock will be released by the next 2132 * task (which is an invalid locking op but in the case 2133 * of the scheduler it's an obvious special-case), so we 2134 * do an early lockdep release here: 2135 */ 2136#ifndef __ARCH_WANT_UNLOCKED_CTXSW 2137 spin_release(&rq->lock.dep_map, 1, _THIS_IP_); 2138#endif 2139 2140 context_tracking_task_switch(prev, next); 2141 /* Here we just switch the register state and the stack. */ 2142 switch_to(prev, next, prev); 2143 2144 barrier(); 2145 /* 2146 * this_rq must be evaluated again because prev may have moved 2147 * CPUs since it called schedule(), thus the 'rq' on its stack 2148 * frame will be invalid. 2149 */ 2150 finish_task_switch(this_rq(), prev); 2151} 2152 2153/* 2154 * nr_running and nr_context_switches: 2155 * 2156 * externally visible scheduler statistics: current number of runnable 2157 * threads, total number of context switches performed since bootup. 2158 */ 2159unsigned long nr_running(void) 2160{ 2161 unsigned long i, sum = 0; 2162 2163 for_each_online_cpu(i) 2164 sum += cpu_rq(i)->nr_running; 2165 2166 return sum; 2167} 2168 2169unsigned long long nr_context_switches(void) 2170{ 2171 int i; 2172 unsigned long long sum = 0; 2173 2174 for_each_possible_cpu(i) 2175 sum += cpu_rq(i)->nr_switches; 2176 2177 return sum; 2178} 2179 2180unsigned long nr_iowait(void) 2181{ 2182 unsigned long i, sum = 0; 2183 2184 for_each_possible_cpu(i) 2185 sum += atomic_read(&cpu_rq(i)->nr_iowait); 2186 2187 return sum; 2188} 2189 2190unsigned long nr_iowait_cpu(int cpu) 2191{ 2192 struct rq *this = cpu_rq(cpu); 2193 return atomic_read(&this->nr_iowait); 2194} 2195 2196#ifdef CONFIG_SMP 2197 2198/* 2199 * sched_exec - execve() is a valuable balancing opportunity, because at 2200 * this point the task has the smallest effective memory and cache footprint. 2201 */ 2202void sched_exec(void) 2203{ 2204 struct task_struct *p = current; 2205 unsigned long flags; 2206 int dest_cpu; 2207 2208 raw_spin_lock_irqsave(&p->pi_lock, flags); 2209 dest_cpu = p->sched_class->select_task_rq(p, task_cpu(p), SD_BALANCE_EXEC, 0); 2210 if (dest_cpu == smp_processor_id()) 2211 goto unlock; 2212 2213 if (likely(cpu_active(dest_cpu))) { 2214 struct migration_arg arg = { p, dest_cpu }; 2215 2216 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 2217 stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg); 2218 return; 2219 } 2220unlock: 2221 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 2222} 2223 2224#endif 2225 2226DEFINE_PER_CPU(struct kernel_stat, kstat); 2227DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat); 2228 2229EXPORT_PER_CPU_SYMBOL(kstat); 2230EXPORT_PER_CPU_SYMBOL(kernel_cpustat); 2231 2232/* 2233 * Return any ns on the sched_clock that have not yet been accounted in 2234 * @p in case that task is currently running. 2235 * 2236 * Called with task_rq_lock() held on @rq. 2237 */ 2238static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq) 2239{ 2240 u64 ns = 0; 2241 2242 if (task_current(rq, p)) { 2243 update_rq_clock(rq); 2244 ns = rq_clock_task(rq) - p->se.exec_start; 2245 if ((s64)ns < 0) 2246 ns = 0; 2247 } 2248 2249 return ns; 2250} 2251 2252unsigned long long task_delta_exec(struct task_struct *p) 2253{ 2254 unsigned long flags; 2255 struct rq *rq; 2256 u64 ns = 0; 2257 2258 rq = task_rq_lock(p, &flags); 2259 ns = do_task_delta_exec(p, rq); 2260 task_rq_unlock(rq, p, &flags); 2261 2262 return ns; 2263} 2264 2265/* 2266 * Return accounted runtime for the task. 2267 * In case the task is currently running, return the runtime plus current's 2268 * pending runtime that have not been accounted yet. 2269 */ 2270unsigned long long task_sched_runtime(struct task_struct *p) 2271{ 2272 unsigned long flags; 2273 struct rq *rq; 2274 u64 ns = 0; 2275 2276#if defined(CONFIG_64BIT) && defined(CONFIG_SMP) 2277 /* 2278 * 64-bit doesn't need locks to atomically read a 64bit value. 2279 * So we have a optimization chance when the task's delta_exec is 0. 2280 * Reading ->on_cpu is racy, but this is ok. 2281 * 2282 * If we race with it leaving cpu, we'll take a lock. So we're correct. 2283 * If we race with it entering cpu, unaccounted time is 0. This is 2284 * indistinguishable from the read occurring a few cycles earlier. 2285 */ 2286 if (!p->on_cpu) 2287 return p->se.sum_exec_runtime; 2288#endif 2289 2290 rq = task_rq_lock(p, &flags); 2291 ns = p->se.sum_exec_runtime + do_task_delta_exec(p, rq); 2292 task_rq_unlock(rq, p, &flags); 2293 2294 return ns; 2295} 2296 2297/* 2298 * This function gets called by the timer code, with HZ frequency. 2299 * We call it with interrupts disabled. 2300 */ 2301void scheduler_tick(void) 2302{ 2303 int cpu = smp_processor_id(); 2304 struct rq *rq = cpu_rq(cpu); 2305 struct task_struct *curr = rq->curr; 2306 2307 sched_clock_tick(); 2308 2309 raw_spin_lock(&rq->lock); 2310 update_rq_clock(rq); 2311 curr->sched_class->task_tick(rq, curr, 0); 2312 update_cpu_load_active(rq); 2313 raw_spin_unlock(&rq->lock); 2314 2315 perf_event_task_tick(); 2316 2317#ifdef CONFIG_SMP 2318 rq->idle_balance = idle_cpu(cpu); 2319 trigger_load_balance(rq, cpu); 2320#endif 2321 rq_last_tick_reset(rq); 2322} 2323 2324#ifdef CONFIG_NO_HZ_FULL 2325/** 2326 * scheduler_tick_max_deferment 2327 * 2328 * Keep at least one tick per second when a single 2329 * active task is running because the scheduler doesn't 2330 * yet completely support full dynticks environment. 2331 * 2332 * This makes sure that uptime, CFS vruntime, load 2333 * balancing, etc... continue to move forward, even 2334 * with a very low granularity. 2335 * 2336 * Return: Maximum deferment in nanoseconds. 2337 */ 2338u64 scheduler_tick_max_deferment(void) 2339{ 2340 struct rq *rq = this_rq(); 2341 unsigned long next, now = ACCESS_ONCE(jiffies); 2342 2343 next = rq->last_sched_tick + HZ; 2344 2345 if (time_before_eq(next, now)) 2346 return 0; 2347 2348 return jiffies_to_usecs(next - now) * NSEC_PER_USEC; 2349} 2350#endif 2351 2352notrace unsigned long get_parent_ip(unsigned long addr) 2353{ 2354 if (in_lock_functions(addr)) { 2355 addr = CALLER_ADDR2; 2356 if (in_lock_functions(addr)) 2357 addr = CALLER_ADDR3; 2358 } 2359 return addr; 2360} 2361 2362#if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \ 2363 defined(CONFIG_PREEMPT_TRACER)) 2364 2365void __kprobes preempt_count_add(int val) 2366{ 2367#ifdef CONFIG_DEBUG_PREEMPT 2368 /* 2369 * Underflow? 2370 */ 2371 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) 2372 return; 2373#endif 2374 __preempt_count_add(val); 2375#ifdef CONFIG_DEBUG_PREEMPT 2376 /* 2377 * Spinlock count overflowing soon? 2378 */ 2379 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= 2380 PREEMPT_MASK - 10); 2381#endif 2382 if (preempt_count() == val) 2383 trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); 2384} 2385EXPORT_SYMBOL(preempt_count_add); 2386 2387void __kprobes preempt_count_sub(int val) 2388{ 2389#ifdef CONFIG_DEBUG_PREEMPT 2390 /* 2391 * Underflow? 2392 */ 2393 if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) 2394 return; 2395 /* 2396 * Is the spinlock portion underflowing? 2397 */ 2398 if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && 2399 !(preempt_count() & PREEMPT_MASK))) 2400 return; 2401#endif 2402 2403 if (preempt_count() == val) 2404 trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); 2405 __preempt_count_sub(val); 2406} 2407EXPORT_SYMBOL(preempt_count_sub); 2408 2409#endif 2410 2411/* 2412 * Print scheduling while atomic bug: 2413 */ 2414static noinline void __schedule_bug(struct task_struct *prev) 2415{ 2416 if (oops_in_progress) 2417 return; 2418 2419 printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n", 2420 prev->comm, prev->pid, preempt_count()); 2421 2422 debug_show_held_locks(prev); 2423 print_modules(); 2424 if (irqs_disabled()) 2425 print_irqtrace_events(prev); 2426 dump_stack(); 2427 add_taint(TAINT_WARN, LOCKDEP_STILL_OK); 2428} 2429 2430/* 2431 * Various schedule()-time debugging checks and statistics: 2432 */ 2433static inline void schedule_debug(struct task_struct *prev) 2434{ 2435 /* 2436 * Test if we are atomic. Since do_exit() needs to call into 2437 * schedule() atomically, we ignore that path. Otherwise whine 2438 * if we are scheduling when we should not. 2439 */ 2440 if (unlikely(in_atomic_preempt_off() && prev->state != TASK_DEAD)) 2441 __schedule_bug(prev); 2442 rcu_sleep_check(); 2443 2444 profile_hit(SCHED_PROFILING, __builtin_return_address(0)); 2445 2446 schedstat_inc(this_rq(), sched_count); 2447} 2448 2449static void put_prev_task(struct rq *rq, struct task_struct *prev) 2450{ 2451 if (prev->on_rq || rq->skip_clock_update < 0) 2452 update_rq_clock(rq); 2453 prev->sched_class->put_prev_task(rq, prev); 2454} 2455 2456/* 2457 * Pick up the highest-prio task: 2458 */ 2459static inline struct task_struct * 2460pick_next_task(struct rq *rq) 2461{ 2462 const struct sched_class *class; 2463 struct task_struct *p; 2464 2465 /* 2466 * Optimization: we know that if all tasks are in 2467 * the fair class we can call that function directly: 2468 */ 2469 if (likely(rq->nr_running == rq->cfs.h_nr_running)) { 2470 p = fair_sched_class.pick_next_task(rq); 2471 if (likely(p)) 2472 return p; 2473 } 2474 2475 for_each_class(class) { 2476 p = class->pick_next_task(rq); 2477 if (p) 2478 return p; 2479 } 2480 2481 BUG(); /* the idle class will always have a runnable task */ 2482} 2483 2484/* 2485 * __schedule() is the main scheduler function. 2486 * 2487 * The main means of driving the scheduler and thus entering this function are: 2488 * 2489 * 1. Explicit blocking: mutex, semaphore, waitqueue, etc. 2490 * 2491 * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return 2492 * paths. For example, see arch/x86/entry_64.S. 2493 * 2494 * To drive preemption between tasks, the scheduler sets the flag in timer 2495 * interrupt handler scheduler_tick(). 2496 * 2497 * 3. Wakeups don't really cause entry into schedule(). They add a 2498 * task to the run-queue and that's it. 2499 * 2500 * Now, if the new task added to the run-queue preempts the current 2501 * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets 2502 * called on the nearest possible occasion: 2503 * 2504 * - If the kernel is preemptible (CONFIG_PREEMPT=y): 2505 * 2506 * - in syscall or exception context, at the next outmost 2507 * preempt_enable(). (this might be as soon as the wake_up()'s 2508 * spin_unlock()!) 2509 * 2510 * - in IRQ context, return from interrupt-handler to 2511 * preemptible context 2512 * 2513 * - If the kernel is not preemptible (CONFIG_PREEMPT is not set) 2514 * then at the next: 2515 * 2516 * - cond_resched() call 2517 * - explicit schedule() call 2518 * - return from syscall or exception to user-space 2519 * - return from interrupt-handler to user-space 2520 */ 2521static void __sched __schedule(void) 2522{ 2523 struct task_struct *prev, *next; 2524 unsigned long *switch_count; 2525 struct rq *rq; 2526 int cpu; 2527 2528need_resched: 2529 preempt_disable(); 2530 cpu = smp_processor_id(); 2531 rq = cpu_rq(cpu); 2532 rcu_note_context_switch(cpu); 2533 prev = rq->curr; 2534 2535 schedule_debug(prev); 2536 2537 if (sched_feat(HRTICK)) 2538 hrtick_clear(rq); 2539 2540 /* 2541 * Make sure that signal_pending_state()->signal_pending() below 2542 * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE) 2543 * done by the caller to avoid the race with signal_wake_up(). 2544 */ 2545 smp_mb__before_spinlock(); 2546 raw_spin_lock_irq(&rq->lock); 2547 2548 switch_count = &prev->nivcsw; 2549 if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { 2550 if (unlikely(signal_pending_state(prev->state, prev))) { 2551 prev->state = TASK_RUNNING; 2552 } else { 2553 deactivate_task(rq, prev, DEQUEUE_SLEEP); 2554 prev->on_rq = 0; 2555 2556 /* 2557 * If a worker went to sleep, notify and ask workqueue 2558 * whether it wants to wake up a task to maintain 2559 * concurrency. 2560 */ 2561 if (prev->flags & PF_WQ_WORKER) { 2562 struct task_struct *to_wakeup; 2563 2564 to_wakeup = wq_worker_sleeping(prev, cpu); 2565 if (to_wakeup) 2566 try_to_wake_up_local(to_wakeup); 2567 } 2568 } 2569 switch_count = &prev->nvcsw; 2570 } 2571 2572 pre_schedule(rq, prev); 2573 2574 if (unlikely(!rq->nr_running)) 2575 idle_balance(cpu, rq); 2576 2577 put_prev_task(rq, prev); 2578 next = pick_next_task(rq); 2579 clear_tsk_need_resched(prev); 2580 clear_preempt_need_resched(); 2581 rq->skip_clock_update = 0; 2582 2583 if (likely(prev != next)) { 2584 rq->nr_switches++; 2585 rq->curr = next; 2586 ++*switch_count; 2587 2588 context_switch(rq, prev, next); /* unlocks the rq */ 2589 /* 2590 * The context switch have flipped the stack from under us 2591 * and restored the local variables which were saved when 2592 * this task called schedule() in the past. prev == current 2593 * is still correct, but it can be moved to another cpu/rq. 2594 */ 2595 cpu = smp_processor_id(); 2596 rq = cpu_rq(cpu); 2597 } else 2598 raw_spin_unlock_irq(&rq->lock); 2599 2600 post_schedule(rq); 2601 2602 sched_preempt_enable_no_resched(); 2603 if (need_resched()) 2604 goto need_resched; 2605} 2606 2607static inline void sched_submit_work(struct task_struct *tsk) 2608{ 2609 if (!tsk->state || tsk_is_pi_blocked(tsk)) 2610 return; 2611 /* 2612 * If we are going to sleep and we have plugged IO queued, 2613 * make sure to submit it to avoid deadlocks. 2614 */ 2615 if (blk_needs_flush_plug(tsk)) 2616 blk_schedule_flush_plug(tsk); 2617} 2618 2619asmlinkage void __sched schedule(void) 2620{ 2621 struct task_struct *tsk = current; 2622 2623 sched_submit_work(tsk); 2624 __schedule(); 2625} 2626EXPORT_SYMBOL(schedule); 2627 2628#ifdef CONFIG_CONTEXT_TRACKING 2629asmlinkage void __sched schedule_user(void) 2630{ 2631 /* 2632 * If we come here after a random call to set_need_resched(), 2633 * or we have been woken up remotely but the IPI has not yet arrived, 2634 * we haven't yet exited the RCU idle mode. Do it here manually until 2635 * we find a better solution. 2636 */ 2637 user_exit(); 2638 schedule(); 2639 user_enter(); 2640} 2641#endif 2642 2643/** 2644 * schedule_preempt_disabled - called with preemption disabled 2645 * 2646 * Returns with preemption disabled. Note: preempt_count must be 1 2647 */ 2648void __sched schedule_preempt_disabled(void) 2649{ 2650 sched_preempt_enable_no_resched(); 2651 schedule(); 2652 preempt_disable(); 2653} 2654 2655#ifdef CONFIG_PREEMPT 2656/* 2657 * this is the entry point to schedule() from in-kernel preemption 2658 * off of preempt_enable. Kernel preemptions off return from interrupt 2659 * occur there and call schedule directly. 2660 */ 2661asmlinkage void __sched notrace preempt_schedule(void) 2662{ 2663 /* 2664 * If there is a non-zero preempt_count or interrupts are disabled, 2665 * we do not want to preempt the current task. Just return.. 2666 */ 2667 if (likely(!preemptible())) 2668 return; 2669 2670 do { 2671 __preempt_count_add(PREEMPT_ACTIVE); 2672 __schedule(); 2673 __preempt_count_sub(PREEMPT_ACTIVE); 2674 2675 /* 2676 * Check again in case we missed a preemption opportunity 2677 * between schedule and now. 2678 */ 2679 barrier(); 2680 } while (need_resched()); 2681} 2682EXPORT_SYMBOL(preempt_schedule); 2683#endif /* CONFIG_PREEMPT */ 2684 2685/* 2686 * this is the entry point to schedule() from kernel preemption 2687 * off of irq context. 2688 * Note, that this is called and return with irqs disabled. This will 2689 * protect us against recursive calling from irq. 2690 */ 2691asmlinkage void __sched preempt_schedule_irq(void) 2692{ 2693 enum ctx_state prev_state; 2694 2695 /* Catch callers which need to be fixed */ 2696 BUG_ON(preempt_count() || !irqs_disabled()); 2697 2698 prev_state = exception_enter(); 2699 2700 do { 2701 __preempt_count_add(PREEMPT_ACTIVE); 2702 local_irq_enable(); 2703 __schedule(); 2704 local_irq_disable(); 2705 __preempt_count_sub(PREEMPT_ACTIVE); 2706 2707 /* 2708 * Check again in case we missed a preemption opportunity 2709 * between schedule and now. 2710 */ 2711 barrier(); 2712 } while (need_resched()); 2713 2714 exception_exit(prev_state); 2715} 2716 2717int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags, 2718 void *key) 2719{ 2720 return try_to_wake_up(curr->private, mode, wake_flags); 2721} 2722EXPORT_SYMBOL(default_wake_function); 2723 2724static long __sched 2725sleep_on_common(wait_queue_head_t *q, int state, long timeout) 2726{ 2727 unsigned long flags; 2728 wait_queue_t wait; 2729 2730 init_waitqueue_entry(&wait, current); 2731 2732 __set_current_state(state); 2733 2734 spin_lock_irqsave(&q->lock, flags); 2735 __add_wait_queue(q, &wait); 2736 spin_unlock(&q->lock); 2737 timeout = schedule_timeout(timeout); 2738 spin_lock_irq(&q->lock); 2739 __remove_wait_queue(q, &wait); 2740 spin_unlock_irqrestore(&q->lock, flags); 2741 2742 return timeout; 2743} 2744 2745void __sched interruptible_sleep_on(wait_queue_head_t *q) 2746{ 2747 sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); 2748} 2749EXPORT_SYMBOL(interruptible_sleep_on); 2750 2751long __sched 2752interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout) 2753{ 2754 return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout); 2755} 2756EXPORT_SYMBOL(interruptible_sleep_on_timeout); 2757 2758void __sched sleep_on(wait_queue_head_t *q) 2759{ 2760 sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); 2761} 2762EXPORT_SYMBOL(sleep_on); 2763 2764long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout) 2765{ 2766 return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout); 2767} 2768EXPORT_SYMBOL(sleep_on_timeout); 2769 2770#ifdef CONFIG_RT_MUTEXES 2771 2772/* 2773 * rt_mutex_setprio - set the current priority of a task 2774 * @p: task 2775 * @prio: prio value (kernel-internal form) 2776 * 2777 * This function changes the 'effective' priority of a task. It does 2778 * not touch ->normal_prio like __setscheduler(). 2779 * 2780 * Used by the rt_mutex code to implement priority inheritance logic. 2781 */ 2782void rt_mutex_setprio(struct task_struct *p, int prio) 2783{ 2784 int oldprio, on_rq, running, enqueue_flag = 0; 2785 struct rq *rq; 2786 const struct sched_class *prev_class; 2787 2788 BUG_ON(prio > MAX_PRIO); 2789 2790 rq = __task_rq_lock(p); 2791 2792 /* 2793 * Idle task boosting is a nono in general. There is one 2794 * exception, when PREEMPT_RT and NOHZ is active: 2795 * 2796 * The idle task calls get_next_timer_interrupt() and holds 2797 * the timer wheel base->lock on the CPU and another CPU wants 2798 * to access the timer (probably to cancel it). We can safely 2799 * ignore the boosting request, as the idle CPU runs this code 2800 * with interrupts disabled and will complete the lock 2801 * protected section without being interrupted. So there is no 2802 * real need to boost. 2803 */ 2804 if (unlikely(p == rq->idle)) { 2805 WARN_ON(p != rq->curr); 2806 WARN_ON(p->pi_blocked_on); 2807 goto out_unlock; 2808 } 2809 2810 trace_sched_pi_setprio(p, prio); 2811 p->pi_top_task = rt_mutex_get_top_task(p); 2812 oldprio = p->prio; 2813 prev_class = p->sched_class; 2814 on_rq = p->on_rq; 2815 running = task_current(rq, p); 2816 if (on_rq) 2817 dequeue_task(rq, p, 0); 2818 if (running) 2819 p->sched_class->put_prev_task(rq, p); 2820 2821 /* 2822 * Boosting condition are: 2823 * 1. -rt task is running and holds mutex A 2824 * --> -dl task blocks on mutex A 2825 * 2826 * 2. -dl task is running and holds mutex A 2827 * --> -dl task blocks on mutex A and could preempt the 2828 * running task 2829 */ 2830 if (dl_prio(prio)) { 2831 if (!dl_prio(p->normal_prio) || (p->pi_top_task && 2832 dl_entity_preempt(&p->pi_top_task->dl, &p->dl))) { 2833 p->dl.dl_boosted = 1; 2834 p->dl.dl_throttled = 0; 2835 enqueue_flag = ENQUEUE_REPLENISH; 2836 } else 2837 p->dl.dl_boosted = 0; 2838 p->sched_class = &dl_sched_class; 2839 } else if (rt_prio(prio)) { 2840 if (dl_prio(oldprio)) 2841 p->dl.dl_boosted = 0; 2842 if (oldprio < prio) 2843 enqueue_flag = ENQUEUE_HEAD; 2844 p->sched_class = &rt_sched_class; 2845 } else { 2846 if (dl_prio(oldprio)) 2847 p->dl.dl_boosted = 0; 2848 p->sched_class = &fair_sched_class; 2849 } 2850 2851 p->prio = prio; 2852 2853 if (running) 2854 p->sched_class->set_curr_task(rq); 2855 if (on_rq) 2856 enqueue_task(rq, p, enqueue_flag); 2857 2858 check_class_changed(rq, p, prev_class, oldprio); 2859out_unlock: 2860 __task_rq_unlock(rq); 2861} 2862#endif 2863 2864void set_user_nice(struct task_struct *p, long nice) 2865{ 2866 int old_prio, delta, on_rq; 2867 unsigned long flags; 2868 struct rq *rq; 2869 2870 if (TASK_NICE(p) == nice || nice < -20 || nice > 19) 2871 return; 2872 /* 2873 * We have to be careful, if called from sys_setpriority(), 2874 * the task might be in the middle of scheduling on another CPU. 2875 */ 2876 rq = task_rq_lock(p, &flags); 2877 /* 2878 * The RT priorities are set via sched_setscheduler(), but we still 2879 * allow the 'normal' nice value to be set - but as expected 2880 * it wont have any effect on scheduling until the task is 2881 * SCHED_DEADLINE, SCHED_FIFO or SCHED_RR: 2882 */ 2883 if (task_has_dl_policy(p) || task_has_rt_policy(p)) { 2884 p->static_prio = NICE_TO_PRIO(nice); 2885 goto out_unlock; 2886 } 2887 on_rq = p->on_rq; 2888 if (on_rq) 2889 dequeue_task(rq, p, 0); 2890 2891 p->static_prio = NICE_TO_PRIO(nice); 2892 set_load_weight(p); 2893 old_prio = p->prio; 2894 p->prio = effective_prio(p); 2895 delta = p->prio - old_prio; 2896 2897 if (on_rq) { 2898 enqueue_task(rq, p, 0); 2899 /* 2900 * If the task increased its priority or is running and 2901 * lowered its priority, then reschedule its CPU: 2902 */ 2903 if (delta < 0 || (delta > 0 && task_running(rq, p))) 2904 resched_task(rq->curr); 2905 } 2906out_unlock: 2907 task_rq_unlock(rq, p, &flags); 2908} 2909EXPORT_SYMBOL(set_user_nice); 2910 2911/* 2912 * can_nice - check if a task can reduce its nice value 2913 * @p: task 2914 * @nice: nice value 2915 */ 2916int can_nice(const struct task_struct *p, const int nice) 2917{ 2918 /* convert nice value [19,-20] to rlimit style value [1,40] */ 2919 int nice_rlim = 20 - nice; 2920 2921 return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) || 2922 capable(CAP_SYS_NICE)); 2923} 2924 2925#ifdef __ARCH_WANT_SYS_NICE 2926 2927/* 2928 * sys_nice - change the priority of the current process. 2929 * @increment: priority increment 2930 * 2931 * sys_setpriority is a more generic, but much slower function that 2932 * does similar things. 2933 */ 2934SYSCALL_DEFINE1(nice, int, increment) 2935{ 2936 long nice, retval; 2937 2938 /* 2939 * Setpriority might change our priority at the same moment. 2940 * We don't have to worry. Conceptually one call occurs first 2941 * and we have a single winner. 2942 */ 2943 if (increment < -40) 2944 increment = -40; 2945 if (increment > 40) 2946 increment = 40; 2947 2948 nice = TASK_NICE(current) + increment; 2949 if (nice < -20) 2950 nice = -20; 2951 if (nice > 19) 2952 nice = 19; 2953 2954 if (increment < 0 && !can_nice(current, nice)) 2955 return -EPERM; 2956 2957 retval = security_task_setnice(current, nice); 2958 if (retval) 2959 return retval; 2960 2961 set_user_nice(current, nice); 2962 return 0; 2963} 2964 2965#endif 2966 2967/** 2968 * task_prio - return the priority value of a given task. 2969 * @p: the task in question. 2970 * 2971 * Return: The priority value as seen by users in /proc. 2972 * RT tasks are offset by -200. Normal tasks are centered 2973 * around 0, value goes from -16 to +15. 2974 */ 2975int task_prio(const struct task_struct *p) 2976{ 2977 return p->prio - MAX_RT_PRIO; 2978} 2979 2980/** 2981 * task_nice - return the nice value of a given task. 2982 * @p: the task in question. 2983 * 2984 * Return: The nice value [ -20 ... 0 ... 19 ]. 2985 */ 2986int task_nice(const struct task_struct *p) 2987{ 2988 return TASK_NICE(p); 2989} 2990EXPORT_SYMBOL(task_nice); 2991 2992/** 2993 * idle_cpu - is a given cpu idle currently? 2994 * @cpu: the processor in question. 2995 * 2996 * Return: 1 if the CPU is currently idle. 0 otherwise. 2997 */ 2998int idle_cpu(int cpu) 2999{ 3000 struct rq *rq = cpu_rq(cpu); 3001 3002 if (rq->curr != rq->idle) 3003 return 0; 3004 3005 if (rq->nr_running) 3006 return 0; 3007 3008#ifdef CONFIG_SMP 3009 if (!llist_empty(&rq->wake_list)) 3010 return 0; 3011#endif 3012 3013 return 1; 3014} 3015 3016/** 3017 * idle_task - return the idle task for a given cpu. 3018 * @cpu: the processor in question. 3019 * 3020 * Return: The idle task for the cpu @cpu. 3021 */ 3022struct task_struct *idle_task(int cpu) 3023{ 3024 return cpu_rq(cpu)->idle; 3025} 3026 3027/** 3028 * find_process_by_pid - find a process with a matching PID value. 3029 * @pid: the pid in question. 3030 * 3031 * The task of @pid, if found. %NULL otherwise. 3032 */ 3033static struct task_struct *find_process_by_pid(pid_t pid) 3034{ 3035 return pid ? find_task_by_vpid(pid) : current; 3036} 3037 3038/* 3039 * This function initializes the sched_dl_entity of a newly becoming 3040 * SCHED_DEADLINE task. 3041 * 3042 * Only the static values are considered here, the actual runtime and the 3043 * absolute deadline will be properly calculated when the task is enqueued 3044 * for the first time with its new policy. 3045 */ 3046static void 3047__setparam_dl(struct task_struct *p, const struct sched_attr *attr) 3048{ 3049 struct sched_dl_entity *dl_se = &p->dl; 3050 3051 init_dl_task_timer(dl_se); 3052 dl_se->dl_runtime = attr->sched_runtime; 3053 dl_se->dl_deadline = attr->sched_deadline; 3054 dl_se->dl_period = attr->sched_period ?: dl_se->dl_deadline; 3055 dl_se->flags = attr->sched_flags; 3056 dl_se->dl_throttled = 0; 3057 dl_se->dl_new = 1; 3058} 3059 3060/* Actually do priority change: must hold pi & rq lock. */ 3061static void __setscheduler(struct rq *rq, struct task_struct *p, 3062 const struct sched_attr *attr) 3063{ 3064 int policy = attr->sched_policy; 3065 3066 p->policy = policy; 3067 3068 if (dl_policy(policy)) 3069 __setparam_dl(p, attr); 3070 else if (rt_policy(policy)) 3071 p->rt_priority = attr->sched_priority; 3072 else 3073 p->static_prio = NICE_TO_PRIO(attr->sched_nice); 3074 3075 p->normal_prio = normal_prio(p); 3076 p->prio = rt_mutex_getprio(p); 3077 3078 if (dl_prio(p->prio)) 3079 p->sched_class = &dl_sched_class; 3080 else if (rt_prio(p->prio)) 3081 p->sched_class = &rt_sched_class; 3082 else 3083 p->sched_class = &fair_sched_class; 3084 3085 set_load_weight(p); 3086} 3087 3088static void 3089__getparam_dl(struct task_struct *p, struct sched_attr *attr) 3090{ 3091 struct sched_dl_entity *dl_se = &p->dl; 3092 3093 attr->sched_priority = p->rt_priority; 3094 attr->sched_runtime = dl_se->dl_runtime; 3095 attr->sched_deadline = dl_se->dl_deadline; 3096 attr->sched_period = dl_se->dl_period; 3097 attr->sched_flags = dl_se->flags; 3098} 3099 3100/* 3101 * This function validates the new parameters of a -deadline task. 3102 * We ask for the deadline not being zero, and greater or equal 3103 * than the runtime, as well as the period of being zero or 3104 * greater than deadline. 3105 */ 3106static bool 3107__checkparam_dl(const struct sched_attr *attr) 3108{ 3109 return attr && attr->sched_deadline != 0 && 3110 (attr->sched_period == 0 || 3111 (s64)(attr->sched_period - attr->sched_deadline) >= 0) && 3112 (s64)(attr->sched_deadline - attr->sched_runtime ) >= 0; 3113} 3114 3115/* 3116 * check the target process has a UID that matches the current process's 3117 */ 3118static bool check_same_owner(struct task_struct *p) 3119{ 3120 const struct cred *cred = current_cred(), *pcred; 3121 bool match; 3122 3123 rcu_read_lock(); 3124 pcred = __task_cred(p); 3125 match = (uid_eq(cred->euid, pcred->euid) || 3126 uid_eq(cred->euid, pcred->uid)); 3127 rcu_read_unlock(); 3128 return match; 3129} 3130 3131static int __sched_setscheduler(struct task_struct *p, 3132 const struct sched_attr *attr, 3133 bool user) 3134{ 3135 int retval, oldprio, oldpolicy = -1, on_rq, running; 3136 int policy = attr->sched_policy; 3137 unsigned long flags; 3138 const struct sched_class *prev_class; 3139 struct rq *rq; 3140 int reset_on_fork; 3141 3142 /* may grab non-irq protected spin_locks */ 3143 BUG_ON(in_interrupt()); 3144recheck: 3145 /* double check policy once rq lock held */ 3146 if (policy < 0) { 3147 reset_on_fork = p->sched_reset_on_fork; 3148 policy = oldpolicy = p->policy; 3149 } else { 3150 reset_on_fork = !!(policy & SCHED_RESET_ON_FORK); 3151 policy &= ~SCHED_RESET_ON_FORK; 3152 3153 if (policy != SCHED_DEADLINE && 3154 policy != SCHED_FIFO && policy != SCHED_RR && 3155 policy != SCHED_NORMAL && policy != SCHED_BATCH && 3156 policy != SCHED_IDLE) 3157 return -EINVAL; 3158 } 3159 3160 /* 3161 * Valid priorities for SCHED_FIFO and SCHED_RR are 3162 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL, 3163 * SCHED_BATCH and SCHED_IDLE is 0. 3164 */ 3165 if (attr->sched_priority < 0 || 3166 (p->mm && attr->sched_priority > MAX_USER_RT_PRIO-1) || 3167 (!p->mm && attr->sched_priority > MAX_RT_PRIO-1)) 3168 return -EINVAL; 3169 if ((dl_policy(policy) && !__checkparam_dl(attr)) || 3170 (rt_policy(policy) != (attr->sched_priority != 0))) 3171 return -EINVAL; 3172 3173 /* 3174 * Allow unprivileged RT tasks to decrease priority: 3175 */ 3176 if (user && !capable(CAP_SYS_NICE)) { 3177 if (fair_policy(policy)) { 3178 if (!can_nice(p, attr->sched_nice)) 3179 return -EPERM; 3180 } 3181 3182 if (rt_policy(policy)) { 3183 unsigned long rlim_rtprio = 3184 task_rlimit(p, RLIMIT_RTPRIO); 3185 3186 /* can't set/change the rt policy */ 3187 if (policy != p->policy && !rlim_rtprio) 3188 return -EPERM; 3189 3190 /* can't increase priority */ 3191 if (attr->sched_priority > p->rt_priority && 3192 attr->sched_priority > rlim_rtprio) 3193 return -EPERM; 3194 } 3195 3196 /* 3197 * Treat SCHED_IDLE as nice 20. Only allow a switch to 3198 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it. 3199 */ 3200 if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) { 3201 if (!can_nice(p, TASK_NICE(p))) 3202 return -EPERM; 3203 } 3204 3205 /* can't change other user's priorities */ 3206 if (!check_same_owner(p)) 3207 return -EPERM; 3208 3209 /* Normal users shall not reset the sched_reset_on_fork flag */ 3210 if (p->sched_reset_on_fork && !reset_on_fork) 3211 return -EPERM; 3212 } 3213 3214 if (user) { 3215 retval = security_task_setscheduler(p); 3216 if (retval) 3217 return retval; 3218 } 3219 3220 /* 3221 * make sure no PI-waiters arrive (or leave) while we are 3222 * changing the priority of the task: 3223 * 3224 * To be able to change p->policy safely, the appropriate 3225 * runqueue lock must be held. 3226 */ 3227 rq = task_rq_lock(p, &flags); 3228 3229 /* 3230 * Changing the policy of the stop threads its a very bad idea 3231 */ 3232 if (p == rq->stop) { 3233 task_rq_unlock(rq, p, &flags); 3234 return -EINVAL; 3235 } 3236 3237 /* 3238 * If not changing anything there's no need to proceed further: 3239 */ 3240 if (unlikely(policy == p->policy)) { 3241 if (fair_policy(policy) && attr->sched_nice != TASK_NICE(p)) 3242 goto change; 3243 if (rt_policy(policy) && attr->sched_priority != p->rt_priority) 3244 goto change; 3245 if (dl_policy(policy)) 3246 goto change; 3247 3248 task_rq_unlock(rq, p, &flags); 3249 return 0; 3250 } 3251change: 3252 3253#ifdef CONFIG_RT_GROUP_SCHED 3254 if (user) { 3255 /* 3256 * Do not allow realtime tasks into groups that have no runtime 3257 * assigned. 3258 */ 3259 if (rt_bandwidth_enabled() && rt_policy(policy) && 3260 task_group(p)->rt_bandwidth.rt_runtime == 0 && 3261 !task_group_is_autogroup(task_group(p))) { 3262 task_rq_unlock(rq, p, &flags); 3263 return -EPERM; 3264 } 3265 } 3266#endif 3267 3268 /* recheck policy now with rq lock held */ 3269 if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { 3270 policy = oldpolicy = -1; 3271 task_rq_unlock(rq, p, &flags); 3272 goto recheck; 3273 } 3274 on_rq = p->on_rq; 3275 running = task_current(rq, p); 3276 if (on_rq) 3277 dequeue_task(rq, p, 0); 3278 if (running) 3279 p->sched_class->put_prev_task(rq, p); 3280 3281 p->sched_reset_on_fork = reset_on_fork; 3282 3283 oldprio = p->prio; 3284 prev_class = p->sched_class; 3285 __setscheduler(rq, p, attr); 3286 3287 if (running) 3288 p->sched_class->set_curr_task(rq); 3289 if (on_rq) 3290 enqueue_task(rq, p, 0); 3291 3292 check_class_changed(rq, p, prev_class, oldprio); 3293 task_rq_unlock(rq, p, &flags); 3294 3295 rt_mutex_adjust_pi(p); 3296 3297 return 0; 3298} 3299 3300/** 3301 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. 3302 * @p: the task in question. 3303 * @policy: new policy. 3304 * @param: structure containing the new RT priority. 3305 * 3306 * Return: 0 on success. An error code otherwise. 3307 * 3308 * NOTE that the task may be already dead. 3309 */ 3310int sched_setscheduler(struct task_struct *p, int policy, 3311 const struct sched_param *param) 3312{ 3313 struct sched_attr attr = { 3314 .sched_policy = policy, 3315 .sched_priority = param->sched_priority 3316 }; 3317 return __sched_setscheduler(p, &attr, true); 3318} 3319EXPORT_SYMBOL_GPL(sched_setscheduler); 3320 3321int sched_setattr(struct task_struct *p, const struct sched_attr *attr) 3322{ 3323 return __sched_setscheduler(p, attr, true); 3324} 3325EXPORT_SYMBOL_GPL(sched_setattr); 3326 3327/** 3328 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace. 3329 * @p: the task in question. 3330 * @policy: new policy. 3331 * @param: structure containing the new RT priority. 3332 * 3333 * Just like sched_setscheduler, only don't bother checking if the 3334 * current context has permission. For example, this is needed in 3335 * stop_machine(): we create temporary high priority worker threads, 3336 * but our caller might not have that capability. 3337 * 3338 * Return: 0 on success. An error code otherwise. 3339 */ 3340int sched_setscheduler_nocheck(struct task_struct *p, int policy, 3341 const struct sched_param *param) 3342{ 3343 struct sched_attr attr = { 3344 .sched_policy = policy, 3345 .sched_priority = param->sched_priority 3346 }; 3347 return __sched_setscheduler(p, &attr, false); 3348} 3349 3350static int 3351do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) 3352{ 3353 struct sched_param lparam; 3354 struct task_struct *p; 3355 int retval; 3356 3357 if (!param || pid < 0) 3358 return -EINVAL; 3359 if (copy_from_user(&lparam, param, sizeof(struct sched_param))) 3360 return -EFAULT; 3361 3362 rcu_read_lock(); 3363 retval = -ESRCH; 3364 p = find_process_by_pid(pid); 3365 if (p != NULL) 3366 retval = sched_setscheduler(p, policy, &lparam); 3367 rcu_read_unlock(); 3368 3369 return retval; 3370} 3371 3372/* 3373 * Mimics kernel/events/core.c perf_copy_attr(). 3374 */ 3375static int sched_copy_attr(struct sched_attr __user *uattr, 3376 struct sched_attr *attr) 3377{ 3378 u32 size; 3379 int ret; 3380 3381 if (!access_ok(VERIFY_WRITE, uattr, SCHED_ATTR_SIZE_VER0)) 3382 return -EFAULT; 3383 3384 /* 3385 * zero the full structure, so that a short copy will be nice. 3386 */ 3387 memset(attr, 0, sizeof(*attr)); 3388 3389 ret = get_user(size, &uattr->size); 3390 if (ret) 3391 return ret; 3392 3393 if (size > PAGE_SIZE) /* silly large */ 3394 goto err_size; 3395 3396 if (!size) /* abi compat */ 3397 size = SCHED_ATTR_SIZE_VER0; 3398 3399 if (size < SCHED_ATTR_SIZE_VER0) 3400 goto err_size; 3401 3402 /* 3403 * If we're handed a bigger struct than we know of, 3404 * ensure all the unknown bits are 0 - i.e. new 3405 * user-space does not rely on any kernel feature 3406 * extensions we dont know about yet. 3407 */ 3408 if (size > sizeof(*attr)) { 3409 unsigned char __user *addr; 3410 unsigned char __user *end; 3411 unsigned char val; 3412 3413 addr = (void __user *)uattr + sizeof(*attr); 3414 end = (void __user *)uattr + size; 3415 3416 for (; addr < end; addr++) { 3417 ret = get_user(val, addr); 3418 if (ret) 3419 return ret; 3420 if (val) 3421 goto err_size; 3422 } 3423 size = sizeof(*attr); 3424 } 3425 3426 ret = copy_from_user(attr, uattr, size); 3427 if (ret) 3428 return -EFAULT; 3429 3430 /* 3431 * XXX: do we want to be lenient like existing syscalls; or do we want 3432 * to be strict and return an error on out-of-bounds values? 3433 */ 3434 attr->sched_nice = clamp(attr->sched_nice, -20, 19); 3435 3436out: 3437 return ret; 3438 3439err_size: 3440 put_user(sizeof(*attr), &uattr->size); 3441 ret = -E2BIG; 3442 goto out; 3443} 3444 3445/** 3446 * sys_sched_setscheduler - set/change the scheduler policy and RT priority 3447 * @pid: the pid in question. 3448 * @policy: new policy. 3449 * @param: structure containing the new RT priority. 3450 * 3451 * Return: 0 on success. An error code otherwise. 3452 */ 3453SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy, 3454 struct sched_param __user *, param) 3455{ 3456 /* negative values for policy are not valid */ 3457 if (policy < 0) 3458 return -EINVAL; 3459 3460 return do_sched_setscheduler(pid, policy, param); 3461} 3462 3463/** 3464 * sys_sched_setparam - set/change the RT priority of a thread 3465 * @pid: the pid in question. 3466 * @param: structure containing the new RT priority. 3467 * 3468 * Return: 0 on success. An error code otherwise. 3469 */ 3470SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param) 3471{ 3472 return do_sched_setscheduler(pid, -1, param); 3473} 3474 3475/** 3476 * sys_sched_setattr - same as above, but with extended sched_attr 3477 * @pid: the pid in question. 3478 * @attr: structure containing the extended parameters. 3479 */ 3480SYSCALL_DEFINE2(sched_setattr, pid_t, pid, struct sched_attr __user *, uattr) 3481{ 3482 struct sched_attr attr; 3483 struct task_struct *p; 3484 int retval; 3485 3486 if (!uattr || pid < 0) 3487 return -EINVAL; 3488 3489 if (sched_copy_attr(uattr, &attr)) 3490 return -EFAULT; 3491 3492 rcu_read_lock(); 3493 retval = -ESRCH; 3494 p = find_process_by_pid(pid); 3495 if (p != NULL) 3496 retval = sched_setattr(p, &attr); 3497 rcu_read_unlock(); 3498 3499 return retval; 3500} 3501 3502/** 3503 * sys_sched_getscheduler - get the policy (scheduling class) of a thread 3504 * @pid: the pid in question. 3505 * 3506 * Return: On success, the policy of the thread. Otherwise, a negative error 3507 * code. 3508 */ 3509SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid) 3510{ 3511 struct task_struct *p; 3512 int retval; 3513 3514 if (pid < 0) 3515 return -EINVAL; 3516 3517 retval = -ESRCH; 3518 rcu_read_lock(); 3519 p = find_process_by_pid(pid); 3520 if (p) { 3521 retval = security_task_getscheduler(p); 3522 if (!retval) 3523 retval = p->policy 3524 | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0); 3525 } 3526 rcu_read_unlock(); 3527 return retval; 3528} 3529 3530/** 3531 * sys_sched_getparam - get the RT priority of a thread 3532 * @pid: the pid in question. 3533 * @param: structure containing the RT priority. 3534 * 3535 * Return: On success, 0 and the RT priority is in @param. Otherwise, an error 3536 * code. 3537 */ 3538SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param) 3539{ 3540 struct sched_param lp; 3541 struct task_struct *p; 3542 int retval; 3543 3544 if (!param || pid < 0) 3545 return -EINVAL; 3546 3547 rcu_read_lock(); 3548 p = find_process_by_pid(pid); 3549 retval = -ESRCH; 3550 if (!p) 3551 goto out_unlock; 3552 3553 retval = security_task_getscheduler(p); 3554 if (retval) 3555 goto out_unlock; 3556 3557 if (task_has_dl_policy(p)) { 3558 retval = -EINVAL; 3559 goto out_unlock; 3560 } 3561 lp.sched_priority = p->rt_priority; 3562 rcu_read_unlock(); 3563 3564 /* 3565 * This one might sleep, we cannot do it with a spinlock held ... 3566 */ 3567 retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; 3568 3569 return retval; 3570 3571out_unlock: 3572 rcu_read_unlock(); 3573 return retval; 3574} 3575 3576static int sched_read_attr(struct sched_attr __user *uattr, 3577 struct sched_attr *attr, 3578 unsigned int usize) 3579{ 3580 int ret; 3581 3582 if (!access_ok(VERIFY_WRITE, uattr, usize)) 3583 return -EFAULT; 3584 3585 /* 3586 * If we're handed a smaller struct than we know of, 3587 * ensure all the unknown bits are 0 - i.e. old 3588 * user-space does not get uncomplete information. 3589 */ 3590 if (usize < sizeof(*attr)) { 3591 unsigned char *addr; 3592 unsigned char *end; 3593 3594 addr = (void *)attr + usize; 3595 end = (void *)attr + sizeof(*attr); 3596 3597 for (; addr < end; addr++) { 3598 if (*addr) 3599 goto err_size; 3600 } 3601 3602 attr->size = usize; 3603 } 3604 3605 ret = copy_to_user(uattr, attr, usize); 3606 if (ret) 3607 return -EFAULT; 3608 3609out: 3610 return ret; 3611 3612err_size: 3613 ret = -E2BIG; 3614 goto out; 3615} 3616 3617/** 3618 * sys_sched_getattr - similar to sched_getparam, but with sched_attr 3619 * @pid: the pid in question. 3620 * @attr: structure containing the extended parameters. 3621 * @size: sizeof(attr) for fwd/bwd comp. 3622 */ 3623SYSCALL_DEFINE3(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr, 3624 unsigned int, size) 3625{ 3626 struct sched_attr attr = { 3627 .size = sizeof(struct sched_attr), 3628 }; 3629 struct task_struct *p; 3630 int retval; 3631 3632 if (!uattr || pid < 0 || size > PAGE_SIZE || 3633 size < SCHED_ATTR_SIZE_VER0) 3634 return -EINVAL; 3635 3636 rcu_read_lock(); 3637 p = find_process_by_pid(pid); 3638 retval = -ESRCH; 3639 if (!p) 3640 goto out_unlock; 3641 3642 retval = security_task_getscheduler(p); 3643 if (retval) 3644 goto out_unlock; 3645 3646 attr.sched_policy = p->policy; 3647 if (task_has_dl_policy(p)) 3648 __getparam_dl(p, &attr); 3649 else if (task_has_rt_policy(p)) 3650 attr.sched_priority = p->rt_priority; 3651 else 3652 attr.sched_nice = TASK_NICE(p); 3653 3654 rcu_read_unlock(); 3655 3656 retval = sched_read_attr(uattr, &attr, size); 3657 return retval; 3658 3659out_unlock: 3660 rcu_read_unlock(); 3661 return retval; 3662} 3663 3664long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) 3665{ 3666 cpumask_var_t cpus_allowed, new_mask; 3667 struct task_struct *p; 3668 int retval; 3669 3670 rcu_read_lock(); 3671 3672 p = find_process_by_pid(pid); 3673 if (!p) { 3674 rcu_read_unlock(); 3675 return -ESRCH; 3676 } 3677 3678 /* Prevent p going away */ 3679 get_task_struct(p); 3680 rcu_read_unlock(); 3681 3682 if (p->flags & PF_NO_SETAFFINITY) { 3683 retval = -EINVAL; 3684 goto out_put_task; 3685 } 3686 if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) { 3687 retval = -ENOMEM; 3688 goto out_put_task; 3689 } 3690 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) { 3691 retval = -ENOMEM; 3692 goto out_free_cpus_allowed; 3693 } 3694 retval = -EPERM; 3695 if (!check_same_owner(p)) { 3696 rcu_read_lock(); 3697 if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) { 3698 rcu_read_unlock(); 3699 goto out_unlock; 3700 } 3701 rcu_read_unlock(); 3702 } 3703 3704 retval = security_task_setscheduler(p); 3705 if (retval) 3706 goto out_unlock; 3707 3708 cpuset_cpus_allowed(p, cpus_allowed); 3709 cpumask_and(new_mask, in_mask, cpus_allowed); 3710again: 3711 retval = set_cpus_allowed_ptr(p, new_mask); 3712 3713 if (!retval) { 3714 cpuset_cpus_allowed(p, cpus_allowed); 3715 if (!cpumask_subset(new_mask, cpus_allowed)) { 3716 /* 3717 * We must have raced with a concurrent cpuset 3718 * update. Just reset the cpus_allowed to the 3719 * cpuset's cpus_allowed 3720 */ 3721 cpumask_copy(new_mask, cpus_allowed); 3722 goto again; 3723 } 3724 } 3725out_unlock: 3726 free_cpumask_var(new_mask); 3727out_free_cpus_allowed: 3728 free_cpumask_var(cpus_allowed); 3729out_put_task: 3730 put_task_struct(p); 3731 return retval; 3732} 3733 3734static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, 3735 struct cpumask *new_mask) 3736{ 3737 if (len < cpumask_size()) 3738 cpumask_clear(new_mask); 3739 else if (len > cpumask_size()) 3740 len = cpumask_size(); 3741 3742 return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; 3743} 3744 3745/** 3746 * sys_sched_setaffinity - set the cpu affinity of a process 3747 * @pid: pid of the process 3748 * @len: length in bytes of the bitmask pointed to by user_mask_ptr 3749 * @user_mask_ptr: user-space pointer to the new cpu mask 3750 * 3751 * Return: 0 on success. An error code otherwise. 3752 */ 3753SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len, 3754 unsigned long __user *, user_mask_ptr) 3755{ 3756 cpumask_var_t new_mask; 3757 int retval; 3758 3759 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) 3760 return -ENOMEM; 3761 3762 retval = get_user_cpu_mask(user_mask_ptr, len, new_mask); 3763 if (retval == 0) 3764 retval = sched_setaffinity(pid, new_mask); 3765 free_cpumask_var(new_mask); 3766 return retval; 3767} 3768 3769long sched_getaffinity(pid_t pid, struct cpumask *mask) 3770{ 3771 struct task_struct *p; 3772 unsigned long flags; 3773 int retval; 3774 3775 rcu_read_lock(); 3776 3777 retval = -ESRCH; 3778 p = find_process_by_pid(pid); 3779 if (!p) 3780 goto out_unlock; 3781 3782 retval = security_task_getscheduler(p); 3783 if (retval) 3784 goto out_unlock; 3785 3786 raw_spin_lock_irqsave(&p->pi_lock, flags); 3787 cpumask_and(mask, &p->cpus_allowed, cpu_active_mask); 3788 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 3789 3790out_unlock: 3791 rcu_read_unlock(); 3792 3793 return retval; 3794} 3795 3796/** 3797 * sys_sched_getaffinity - get the cpu affinity of a process 3798 * @pid: pid of the process 3799 * @len: length in bytes of the bitmask pointed to by user_mask_ptr 3800 * @user_mask_ptr: user-space pointer to hold the current cpu mask 3801 * 3802 * Return: 0 on success. An error code otherwise. 3803 */ 3804SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len, 3805 unsigned long __user *, user_mask_ptr) 3806{ 3807 int ret; 3808 cpumask_var_t mask; 3809 3810 if ((len * BITS_PER_BYTE) < nr_cpu_ids) 3811 return -EINVAL; 3812 if (len & (sizeof(unsigned long)-1)) 3813 return -EINVAL; 3814 3815 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) 3816 return -ENOMEM; 3817 3818 ret = sched_getaffinity(pid, mask); 3819 if (ret == 0) { 3820 size_t retlen = min_t(size_t, len, cpumask_size()); 3821 3822 if (copy_to_user(user_mask_ptr, mask, retlen)) 3823 ret = -EFAULT; 3824 else 3825 ret = retlen; 3826 } 3827 free_cpumask_var(mask); 3828 3829 return ret; 3830} 3831 3832/** 3833 * sys_sched_yield - yield the current processor to other threads. 3834 * 3835 * This function yields the current CPU to other tasks. If there are no 3836 * other threads running on this CPU then this function will return. 3837 * 3838 * Return: 0. 3839 */ 3840SYSCALL_DEFINE0(sched_yield) 3841{ 3842 struct rq *rq = this_rq_lock(); 3843 3844 schedstat_inc(rq, yld_count); 3845 current->sched_class->yield_task(rq); 3846 3847 /* 3848 * Since we are going to call schedule() anyway, there's 3849 * no need to preempt or enable interrupts: 3850 */ 3851 __release(rq->lock); 3852 spin_release(&rq->lock.dep_map, 1, _THIS_IP_); 3853 do_raw_spin_unlock(&rq->lock); 3854 sched_preempt_enable_no_resched(); 3855 3856 schedule(); 3857 3858 return 0; 3859} 3860 3861static void __cond_resched(void) 3862{ 3863 __preempt_count_add(PREEMPT_ACTIVE); 3864 __schedule(); 3865 __preempt_count_sub(PREEMPT_ACTIVE); 3866} 3867 3868int __sched _cond_resched(void) 3869{ 3870 if (should_resched()) { 3871 __cond_resched(); 3872 return 1; 3873 } 3874 return 0; 3875} 3876EXPORT_SYMBOL(_cond_resched); 3877 3878/* 3879 * __cond_resched_lock() - if a reschedule is pending, drop the given lock, 3880 * call schedule, and on return reacquire the lock. 3881 * 3882 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level 3883 * operations here to prevent schedule() from being called twice (once via 3884 * spin_unlock(), once by hand). 3885 */ 3886int __cond_resched_lock(spinlock_t *lock) 3887{ 3888 int resched = should_resched(); 3889 int ret = 0; 3890 3891 lockdep_assert_held(lock); 3892 3893 if (spin_needbreak(lock) || resched) { 3894 spin_unlock(lock); 3895 if (resched) 3896 __cond_resched(); 3897 else 3898 cpu_relax(); 3899 ret = 1; 3900 spin_lock(lock); 3901 } 3902 return ret; 3903} 3904EXPORT_SYMBOL(__cond_resched_lock); 3905 3906int __sched __cond_resched_softirq(void) 3907{ 3908 BUG_ON(!in_softirq()); 3909 3910 if (should_resched()) { 3911 local_bh_enable(); 3912 __cond_resched(); 3913 local_bh_disable(); 3914 return 1; 3915 } 3916 return 0; 3917} 3918EXPORT_SYMBOL(__cond_resched_softirq); 3919 3920/** 3921 * yield - yield the current processor to other threads. 3922 * 3923 * Do not ever use this function, there's a 99% chance you're doing it wrong. 3924 * 3925 * The scheduler is at all times free to pick the calling task as the most 3926 * eligible task to run, if removing the yield() call from your code breaks 3927 * it, its already broken. 3928 * 3929 * Typical broken usage is: 3930 * 3931 * while (!event) 3932 * yield(); 3933 * 3934 * where one assumes that yield() will let 'the other' process run that will 3935 * make event true. If the current task is a SCHED_FIFO task that will never 3936 * happen. Never use yield() as a progress guarantee!! 3937 * 3938 * If you want to use yield() to wait for something, use wait_event(). 3939 * If you want to use yield() to be 'nice' for others, use cond_resched(). 3940 * If you still want to use yield(), do not! 3941 */ 3942void __sched yield(void) 3943{ 3944 set_current_state(TASK_RUNNING); 3945 sys_sched_yield(); 3946} 3947EXPORT_SYMBOL(yield); 3948 3949/** 3950 * yield_to - yield the current processor to another thread in 3951 * your thread group, or accelerate that thread toward the 3952 * processor it's on. 3953 * @p: target task 3954 * @preempt: whether task preemption is allowed or not 3955 * 3956 * It's the caller's job to ensure that the target task struct 3957 * can't go away on us before we can do any checks. 3958 * 3959 * Return: 3960 * true (>0) if we indeed boosted the target task. 3961 * false (0) if we failed to boost the target. 3962 * -ESRCH if there's no task to yield to. 3963 */ 3964bool __sched yield_to(struct task_struct *p, bool preempt) 3965{ 3966 struct task_struct *curr = current; 3967 struct rq *rq, *p_rq; 3968 unsigned long flags; 3969 int yielded = 0; 3970 3971 local_irq_save(flags); 3972 rq = this_rq(); 3973 3974again: 3975 p_rq = task_rq(p); 3976 /* 3977 * If we're the only runnable task on the rq and target rq also 3978 * has only one task, there's absolutely no point in yielding. 3979 */ 3980 if (rq->nr_running == 1 && p_rq->nr_running == 1) { 3981 yielded = -ESRCH; 3982 goto out_irq; 3983 } 3984 3985 double_rq_lock(rq, p_rq); 3986 if (task_rq(p) != p_rq) { 3987 double_rq_unlock(rq, p_rq); 3988 goto again; 3989 } 3990 3991 if (!curr->sched_class->yield_to_task) 3992 goto out_unlock; 3993 3994 if (curr->sched_class != p->sched_class) 3995 goto out_unlock; 3996 3997 if (task_running(p_rq, p) || p->state) 3998 goto out_unlock; 3999 4000 yielded = curr->sched_class->yield_to_task(rq, p, preempt); 4001 if (yielded) { 4002 schedstat_inc(rq, yld_count); 4003 /* 4004 * Make p's CPU reschedule; pick_next_entity takes care of 4005 * fairness. 4006 */ 4007 if (preempt && rq != p_rq) 4008 resched_task(p_rq->curr); 4009 } 4010 4011out_unlock: 4012 double_rq_unlock(rq, p_rq); 4013out_irq: 4014 local_irq_restore(flags); 4015 4016 if (yielded > 0) 4017 schedule(); 4018 4019 return yielded; 4020} 4021EXPORT_SYMBOL_GPL(yield_to); 4022 4023/* 4024 * This task is about to go to sleep on IO. Increment rq->nr_iowait so 4025 * that process accounting knows that this is a task in IO wait state. 4026 */ 4027void __sched io_schedule(void) 4028{ 4029 struct rq *rq = raw_rq(); 4030 4031 delayacct_blkio_start(); 4032 atomic_inc(&rq->nr_iowait); 4033 blk_flush_plug(current); 4034 current->in_iowait = 1; 4035 schedule(); 4036 current->in_iowait = 0; 4037 atomic_dec(&rq->nr_iowait); 4038 delayacct_blkio_end(); 4039} 4040EXPORT_SYMBOL(io_schedule); 4041 4042long __sched io_schedule_timeout(long timeout) 4043{ 4044 struct rq *rq = raw_rq(); 4045 long ret; 4046 4047 delayacct_blkio_start(); 4048 atomic_inc(&rq->nr_iowait); 4049 blk_flush_plug(current); 4050 current->in_iowait = 1; 4051 ret = schedule_timeout(timeout); 4052 current->in_iowait = 0; 4053 atomic_dec(&rq->nr_iowait); 4054 delayacct_blkio_end(); 4055 return ret; 4056} 4057 4058/** 4059 * sys_sched_get_priority_max - return maximum RT priority. 4060 * @policy: scheduling class. 4061 * 4062 * Return: On success, this syscall returns the maximum 4063 * rt_priority that can be used by a given scheduling class. 4064 * On failure, a negative error code is returned. 4065 */ 4066SYSCALL_DEFINE1(sched_get_priority_max, int, policy) 4067{ 4068 int ret = -EINVAL; 4069 4070 switch (policy) { 4071 case SCHED_FIFO: 4072 case SCHED_RR: 4073 ret = MAX_USER_RT_PRIO-1; 4074 break; 4075 case SCHED_DEADLINE: 4076 case SCHED_NORMAL: 4077 case SCHED_BATCH: 4078 case SCHED_IDLE: 4079 ret = 0; 4080 break; 4081 } 4082 return ret; 4083} 4084 4085/** 4086 * sys_sched_get_priority_min - return minimum RT priority. 4087 * @policy: scheduling class. 4088 * 4089 * Return: On success, this syscall returns the minimum 4090 * rt_priority that can be used by a given scheduling class. 4091 * On failure, a negative error code is returned. 4092 */ 4093SYSCALL_DEFINE1(sched_get_priority_min, int, policy) 4094{ 4095 int ret = -EINVAL; 4096 4097 switch (policy) { 4098 case SCHED_FIFO: 4099 case SCHED_RR: 4100 ret = 1; 4101 break; 4102 case SCHED_DEADLINE: 4103 case SCHED_NORMAL: 4104 case SCHED_BATCH: 4105 case SCHED_IDLE: 4106 ret = 0; 4107 } 4108 return ret; 4109} 4110 4111/** 4112 * sys_sched_rr_get_interval - return the default timeslice of a process. 4113 * @pid: pid of the process. 4114 * @interval: userspace pointer to the timeslice value. 4115 * 4116 * this syscall writes the default timeslice value of a given process 4117 * into the user-space timespec buffer. A value of '0' means infinity. 4118 * 4119 * Return: On success, 0 and the timeslice is in @interval. Otherwise, 4120 * an error code. 4121 */ 4122SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid, 4123 struct timespec __user *, interval) 4124{ 4125 struct task_struct *p; 4126 unsigned int time_slice; 4127 unsigned long flags; 4128 struct rq *rq; 4129 int retval; 4130 struct timespec t; 4131 4132 if (pid < 0) 4133 return -EINVAL; 4134 4135 retval = -ESRCH; 4136 rcu_read_lock(); 4137 p = find_process_by_pid(pid); 4138 if (!p) 4139 goto out_unlock; 4140 4141 retval = security_task_getscheduler(p); 4142 if (retval) 4143 goto out_unlock; 4144 4145 rq = task_rq_lock(p, &flags); 4146 time_slice = p->sched_class->get_rr_interval(rq, p); 4147 task_rq_unlock(rq, p, &flags); 4148 4149 rcu_read_unlock(); 4150 jiffies_to_timespec(time_slice, &t); 4151 retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; 4152 return retval; 4153 4154out_unlock: 4155 rcu_read_unlock(); 4156 return retval; 4157} 4158 4159static const char stat_nam[] = TASK_STATE_TO_CHAR_STR; 4160 4161void sched_show_task(struct task_struct *p) 4162{ 4163 unsigned long free = 0; 4164 int ppid; 4165 unsigned state; 4166 4167 state = p->state ? __ffs(p->state) + 1 : 0; 4168 printk(KERN_INFO "%-15.15s %c", p->comm, 4169 state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); 4170#if BITS_PER_LONG == 32 4171 if (state == TASK_RUNNING) 4172 printk(KERN_CONT " running "); 4173 else 4174 printk(KERN_CONT " %08lx ", thread_saved_pc(p)); 4175#else 4176 if (state == TASK_RUNNING) 4177 printk(KERN_CONT " running task "); 4178 else 4179 printk(KERN_CONT " %016lx ", thread_saved_pc(p)); 4180#endif 4181#ifdef CONFIG_DEBUG_STACK_USAGE 4182 free = stack_not_used(p); 4183#endif 4184 rcu_read_lock(); 4185 ppid = task_pid_nr(rcu_dereference(p->real_parent)); 4186 rcu_read_unlock(); 4187 printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free, 4188 task_pid_nr(p), ppid, 4189 (unsigned long)task_thread_info(p)->flags); 4190 4191 print_worker_info(KERN_INFO, p); 4192 show_stack(p, NULL); 4193} 4194 4195void show_state_filter(unsigned long state_filter) 4196{ 4197 struct task_struct *g, *p; 4198 4199#if BITS_PER_LONG == 32 4200 printk(KERN_INFO 4201 " task PC stack pid father\n"); 4202#else 4203 printk(KERN_INFO 4204 " task PC stack pid father\n"); 4205#endif 4206 rcu_read_lock(); 4207 do_each_thread(g, p) { 4208 /* 4209 * reset the NMI-timeout, listing all files on a slow 4210 * console might take a lot of time: 4211 */ 4212 touch_nmi_watchdog(); 4213 if (!state_filter || (p->state & state_filter)) 4214 sched_show_task(p); 4215 } while_each_thread(g, p); 4216 4217 touch_all_softlockup_watchdogs(); 4218 4219#ifdef CONFIG_SCHED_DEBUG 4220 sysrq_sched_debug_show(); 4221#endif 4222 rcu_read_unlock(); 4223 /* 4224 * Only show locks if all tasks are dumped: 4225 */ 4226 if (!state_filter) 4227 debug_show_all_locks(); 4228} 4229 4230void init_idle_bootup_task(struct task_struct *idle) 4231{ 4232 idle->sched_class = &idle_sched_class; 4233} 4234 4235/** 4236 * init_idle - set up an idle thread for a given CPU 4237 * @idle: task in question 4238 * @cpu: cpu the idle task belongs to 4239 * 4240 * NOTE: this function does not set the idle thread's NEED_RESCHED 4241 * flag, to make booting more robust. 4242 */ 4243void init_idle(struct task_struct *idle, int cpu) 4244{ 4245 struct rq *rq = cpu_rq(cpu); 4246 unsigned long flags; 4247 4248 raw_spin_lock_irqsave(&rq->lock, flags); 4249 4250 __sched_fork(0, idle); 4251 idle->state = TASK_RUNNING; 4252 idle->se.exec_start = sched_clock(); 4253 4254 do_set_cpus_allowed(idle, cpumask_of(cpu)); 4255 /* 4256 * We're having a chicken and egg problem, even though we are 4257 * holding rq->lock, the cpu isn't yet set to this cpu so the 4258 * lockdep check in task_group() will fail. 4259 * 4260 * Similar case to sched_fork(). / Alternatively we could 4261 * use task_rq_lock() here and obtain the other rq->lock. 4262 * 4263 * Silence PROVE_RCU 4264 */ 4265 rcu_read_lock(); 4266 __set_task_cpu(idle, cpu); 4267 rcu_read_unlock(); 4268 4269 rq->curr = rq->idle = idle; 4270#if defined(CONFIG_SMP) 4271 idle->on_cpu = 1; 4272#endif 4273 raw_spin_unlock_irqrestore(&rq->lock, flags); 4274 4275 /* Set the preempt count _outside_ the spinlocks! */ 4276 init_idle_preempt_count(idle, cpu); 4277 4278 /* 4279 * The idle tasks have their own, simple scheduling class: 4280 */ 4281 idle->sched_class = &idle_sched_class; 4282 ftrace_graph_init_idle_task(idle, cpu); 4283 vtime_init_idle(idle, cpu); 4284#if defined(CONFIG_SMP) 4285 sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu); 4286#endif 4287} 4288 4289#ifdef CONFIG_SMP 4290void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) 4291{ 4292 if (p->sched_class && p->sched_class->set_cpus_allowed) 4293 p->sched_class->set_cpus_allowed(p, new_mask); 4294 4295 cpumask_copy(&p->cpus_allowed, new_mask); 4296 p->nr_cpus_allowed = cpumask_weight(new_mask); 4297} 4298 4299/* 4300 * This is how migration works: 4301 * 4302 * 1) we invoke migration_cpu_stop() on the target CPU using 4303 * stop_one_cpu(). 4304 * 2) stopper starts to run (implicitly forcing the migrated thread 4305 * off the CPU) 4306 * 3) it checks whether the migrated task is still in the wrong runqueue. 4307 * 4) if it's in the wrong runqueue then the migration thread removes 4308 * it and puts it into the right queue. 4309 * 5) stopper completes and stop_one_cpu() returns and the migration 4310 * is done. 4311 */ 4312 4313/* 4314 * Change a given task's CPU affinity. Migrate the thread to a 4315 * proper CPU and schedule it away if the CPU it's executing on 4316 * is removed from the allowed bitmask. 4317 * 4318 * NOTE: the caller must have a valid reference to the task, the 4319 * task must not exit() & deallocate itself prematurely. The 4320 * call is not atomic; no spinlocks may be held. 4321 */ 4322int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) 4323{ 4324 unsigned long flags; 4325 struct rq *rq; 4326 unsigned int dest_cpu; 4327 int ret = 0; 4328 4329 rq = task_rq_lock(p, &flags); 4330 4331 if (cpumask_equal(&p->cpus_allowed, new_mask)) 4332 goto out; 4333 4334 if (!cpumask_intersects(new_mask, cpu_active_mask)) { 4335 ret = -EINVAL; 4336 goto out; 4337 } 4338 4339 do_set_cpus_allowed(p, new_mask); 4340 4341 /* Can the task run on the task's current CPU? If so, we're done */ 4342 if (cpumask_test_cpu(task_cpu(p), new_mask)) 4343 goto out; 4344 4345 dest_cpu = cpumask_any_and(cpu_active_mask, new_mask); 4346 if (p->on_rq) { 4347 struct migration_arg arg = { p, dest_cpu }; 4348 /* Need help from migration thread: drop lock and wait. */ 4349 task_rq_unlock(rq, p, &flags); 4350 stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg); 4351 tlb_migrate_finish(p->mm); 4352 return 0; 4353 } 4354out: 4355 task_rq_unlock(rq, p, &flags); 4356 4357 return ret; 4358} 4359EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr); 4360 4361/* 4362 * Move (not current) task off this cpu, onto dest cpu. We're doing 4363 * this because either it can't run here any more (set_cpus_allowed() 4364 * away from this CPU, or CPU going down), or because we're 4365 * attempting to rebalance this task on exec (sched_exec). 4366 * 4367 * So we race with normal scheduler movements, but that's OK, as long 4368 * as the task is no longer on this CPU. 4369 * 4370 * Returns non-zero if task was successfully migrated. 4371 */ 4372static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) 4373{ 4374 struct rq *rq_dest, *rq_src; 4375 int ret = 0; 4376 4377 if (unlikely(!cpu_active(dest_cpu))) 4378 return ret; 4379 4380 rq_src = cpu_rq(src_cpu); 4381 rq_dest = cpu_rq(dest_cpu); 4382 4383 raw_spin_lock(&p->pi_lock); 4384 double_rq_lock(rq_src, rq_dest); 4385 /* Already moved. */ 4386 if (task_cpu(p) != src_cpu) 4387 goto done; 4388 /* Affinity changed (again). */ 4389 if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) 4390 goto fail; 4391 4392 /* 4393 * If we're not on a rq, the next wake-up will ensure we're 4394 * placed properly. 4395 */ 4396 if (p->on_rq) { 4397 dequeue_task(rq_src, p, 0); 4398 set_task_cpu(p, dest_cpu); 4399 enqueue_task(rq_dest, p, 0); 4400 check_preempt_curr(rq_dest, p, 0); 4401 } 4402done: 4403 ret = 1; 4404fail: 4405 double_rq_unlock(rq_src, rq_dest); 4406 raw_spin_unlock(&p->pi_lock); 4407 return ret; 4408} 4409 4410#ifdef CONFIG_NUMA_BALANCING 4411/* Migrate current task p to target_cpu */ 4412int migrate_task_to(struct task_struct *p, int target_cpu) 4413{ 4414 struct migration_arg arg = { p, target_cpu }; 4415 int curr_cpu = task_cpu(p); 4416 4417 if (curr_cpu == target_cpu) 4418 return 0; 4419 4420 if (!cpumask_test_cpu(target_cpu, tsk_cpus_allowed(p))) 4421 return -EINVAL; 4422 4423 /* TODO: This is not properly updating schedstats */ 4424 4425 return stop_one_cpu(curr_cpu, migration_cpu_stop, &arg); 4426} 4427 4428/* 4429 * Requeue a task on a given node and accurately track the number of NUMA 4430 * tasks on the runqueues 4431 */ 4432void sched_setnuma(struct task_struct *p, int nid) 4433{ 4434 struct rq *rq; 4435 unsigned long flags; 4436 bool on_rq, running; 4437 4438 rq = task_rq_lock(p, &flags); 4439 on_rq = p->on_rq; 4440 running = task_current(rq, p); 4441 4442 if (on_rq) 4443 dequeue_task(rq, p, 0); 4444 if (running) 4445 p->sched_class->put_prev_task(rq, p); 4446 4447 p->numa_preferred_nid = nid; 4448 4449 if (running) 4450 p->sched_class->set_curr_task(rq); 4451 if (on_rq) 4452 enqueue_task(rq, p, 0); 4453 task_rq_unlock(rq, p, &flags); 4454} 4455#endif 4456 4457/* 4458 * migration_cpu_stop - this will be executed by a highprio stopper thread 4459 * and performs thread migration by bumping thread off CPU then 4460 * 'pushing' onto another runqueue. 4461 */ 4462static int migration_cpu_stop(void *data) 4463{ 4464 struct migration_arg *arg = data; 4465 4466 /* 4467 * The original target cpu might have gone down and we might 4468 * be on another cpu but it doesn't matter. 4469 */ 4470 local_irq_disable(); 4471 __migrate_task(arg->task, raw_smp_processor_id(), arg->dest_cpu); 4472 local_irq_enable(); 4473 return 0; 4474} 4475 4476#ifdef CONFIG_HOTPLUG_CPU 4477 4478/* 4479 * Ensures that the idle task is using init_mm right before its cpu goes 4480 * offline. 4481 */ 4482void idle_task_exit(void) 4483{ 4484 struct mm_struct *mm = current->active_mm; 4485 4486 BUG_ON(cpu_online(smp_processor_id())); 4487 4488 if (mm != &init_mm) 4489 switch_mm(mm, &init_mm, current); 4490 mmdrop(mm); 4491} 4492 4493/* 4494 * Since this CPU is going 'away' for a while, fold any nr_active delta 4495 * we might have. Assumes we're called after migrate_tasks() so that the 4496 * nr_active count is stable. 4497 * 4498 * Also see the comment "Global load-average calculations". 4499 */ 4500static void calc_load_migrate(struct rq *rq) 4501{ 4502 long delta = calc_load_fold_active(rq); 4503 if (delta) 4504 atomic_long_add(delta, &calc_load_tasks); 4505} 4506 4507/* 4508 * Migrate all tasks from the rq, sleeping tasks will be migrated by 4509 * try_to_wake_up()->select_task_rq(). 4510 * 4511 * Called with rq->lock held even though we'er in stop_machine() and 4512 * there's no concurrency possible, we hold the required locks anyway 4513 * because of lock validation efforts. 4514 */ 4515static void migrate_tasks(unsigned int dead_cpu) 4516{ 4517 struct rq *rq = cpu_rq(dead_cpu); 4518 struct task_struct *next, *stop = rq->stop; 4519 int dest_cpu; 4520 4521 /* 4522 * Fudge the rq selection such that the below task selection loop 4523 * doesn't get stuck on the currently eligible stop task. 4524 * 4525 * We're currently inside stop_machine() and the rq is either stuck 4526 * in the stop_machine_cpu_stop() loop, or we're executing this code, 4527 * either way we should never end up calling schedule() until we're 4528 * done here. 4529 */ 4530 rq->stop = NULL; 4531 4532 /* 4533 * put_prev_task() and pick_next_task() sched 4534 * class method both need to have an up-to-date 4535 * value of rq->clock[_task] 4536 */ 4537 update_rq_clock(rq); 4538 4539 for ( ; ; ) { 4540 /* 4541 * There's this thread running, bail when that's the only 4542 * remaining thread. 4543 */ 4544 if (rq->nr_running == 1) 4545 break; 4546 4547 next = pick_next_task(rq); 4548 BUG_ON(!next); 4549 next->sched_class->put_prev_task(rq, next); 4550 4551 /* Find suitable destination for @next, with force if needed. */ 4552 dest_cpu = select_fallback_rq(dead_cpu, next); 4553 raw_spin_unlock(&rq->lock); 4554 4555 __migrate_task(next, dead_cpu, dest_cpu); 4556 4557 raw_spin_lock(&rq->lock); 4558 } 4559 4560 rq->stop = stop; 4561} 4562 4563#endif /* CONFIG_HOTPLUG_CPU */ 4564 4565#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL) 4566 4567static struct ctl_table sd_ctl_dir[] = { 4568 { 4569 .procname = "sched_domain", 4570 .mode = 0555, 4571 }, 4572 {} 4573}; 4574 4575static struct ctl_table sd_ctl_root[] = { 4576 { 4577 .procname = "kernel", 4578 .mode = 0555, 4579 .child = sd_ctl_dir, 4580 }, 4581 {} 4582}; 4583 4584static struct ctl_table *sd_alloc_ctl_entry(int n) 4585{ 4586 struct ctl_table *entry = 4587 kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL); 4588 4589 return entry; 4590} 4591 4592static void sd_free_ctl_entry(struct ctl_table **tablep) 4593{ 4594 struct ctl_table *entry; 4595 4596 /* 4597 * In the intermediate directories, both the child directory and 4598 * procname are dynamically allocated and could fail but the mode 4599 * will always be set. In the lowest directory the names are 4600 * static strings and all have proc handlers. 4601 */ 4602 for (entry = *tablep; entry->mode; entry++) { 4603 if (entry->child) 4604 sd_free_ctl_entry(&entry->child); 4605 if (entry->proc_handler == NULL) 4606 kfree(entry->procname); 4607 } 4608 4609 kfree(*tablep); 4610 *tablep = NULL; 4611} 4612 4613static int min_load_idx = 0; 4614static int max_load_idx = CPU_LOAD_IDX_MAX-1; 4615 4616static void 4617set_table_entry(struct ctl_table *entry, 4618 const char *procname, void *data, int maxlen, 4619 umode_t mode, proc_handler *proc_handler, 4620 bool load_idx) 4621{ 4622 entry->procname = procname; 4623 entry->data = data; 4624 entry->maxlen = maxlen; 4625 entry->mode = mode; 4626 entry->proc_handler = proc_handler; 4627 4628 if (load_idx) { 4629 entry->extra1 = &min_load_idx; 4630 entry->extra2 = &max_load_idx; 4631 } 4632} 4633 4634static struct ctl_table * 4635sd_alloc_ctl_domain_table(struct sched_domain *sd) 4636{ 4637 struct ctl_table *table = sd_alloc_ctl_entry(13); 4638 4639 if (table == NULL) 4640 return NULL; 4641 4642 set_table_entry(&table[0], "min_interval", &sd->min_interval, 4643 sizeof(long), 0644, proc_doulongvec_minmax, false); 4644 set_table_entry(&table[1], "max_interval", &sd->max_interval, 4645 sizeof(long), 0644, proc_doulongvec_minmax, false); 4646 set_table_entry(&table[2], "busy_idx", &sd->busy_idx, 4647 sizeof(int), 0644, proc_dointvec_minmax, true); 4648 set_table_entry(&table[3], "idle_idx", &sd->idle_idx, 4649 sizeof(int), 0644, proc_dointvec_minmax, true); 4650 set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx, 4651 sizeof(int), 0644, proc_dointvec_minmax, true); 4652 set_table_entry(&table[5], "wake_idx", &sd->wake_idx, 4653 sizeof(int), 0644, proc_dointvec_minmax, true); 4654 set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx, 4655 sizeof(int), 0644, proc_dointvec_minmax, true); 4656 set_table_entry(&table[7], "busy_factor", &sd->busy_factor, 4657 sizeof(int), 0644, proc_dointvec_minmax, false); 4658 set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct, 4659 sizeof(int), 0644, proc_dointvec_minmax, false); 4660 set_table_entry(&table[9], "cache_nice_tries", 4661 &sd->cache_nice_tries, 4662 sizeof(int), 0644, proc_dointvec_minmax, false); 4663 set_table_entry(&table[10], "flags", &sd->flags, 4664 sizeof(int), 0644, proc_dointvec_minmax, false); 4665 set_table_entry(&table[11], "name", sd->name, 4666 CORENAME_MAX_SIZE, 0444, proc_dostring, false); 4667 /* &table[12] is terminator */ 4668 4669 return table; 4670} 4671 4672static struct ctl_table *sd_alloc_ctl_cpu_table(int cpu) 4673{ 4674 struct ctl_table *entry, *table; 4675 struct sched_domain *sd; 4676 int domain_num = 0, i; 4677 char buf[32]; 4678 4679 for_each_domain(cpu, sd) 4680 domain_num++; 4681 entry = table = sd_alloc_ctl_entry(domain_num + 1); 4682 if (table == NULL) 4683 return NULL; 4684 4685 i = 0; 4686 for_each_domain(cpu, sd) { 4687 snprintf(buf, 32, "domain%d", i); 4688 entry->procname = kstrdup(buf, GFP_KERNEL); 4689 entry->mode = 0555; 4690 entry->child = sd_alloc_ctl_domain_table(sd); 4691 entry++; 4692 i++; 4693 } 4694 return table; 4695} 4696 4697static struct ctl_table_header *sd_sysctl_header; 4698static void register_sched_domain_sysctl(void) 4699{ 4700 int i, cpu_num = num_possible_cpus(); 4701 struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1); 4702 char buf[32]; 4703 4704 WARN_ON(sd_ctl_dir[0].child); 4705 sd_ctl_dir[0].child = entry; 4706 4707 if (entry == NULL) 4708 return; 4709 4710 for_each_possible_cpu(i) { 4711 snprintf(buf, 32, "cpu%d", i); 4712 entry->procname = kstrdup(buf, GFP_KERNEL); 4713 entry->mode = 0555; 4714 entry->child = sd_alloc_ctl_cpu_table(i); 4715 entry++; 4716 } 4717 4718 WARN_ON(sd_sysctl_header); 4719 sd_sysctl_header = register_sysctl_table(sd_ctl_root); 4720} 4721 4722/* may be called multiple times per register */ 4723static void unregister_sched_domain_sysctl(void) 4724{ 4725 if (sd_sysctl_header) 4726 unregister_sysctl_table(sd_sysctl_header); 4727 sd_sysctl_header = NULL; 4728 if (sd_ctl_dir[0].child) 4729 sd_free_ctl_entry(&sd_ctl_dir[0].child); 4730} 4731#else 4732static void register_sched_domain_sysctl(void) 4733{ 4734} 4735static void unregister_sched_domain_sysctl(void) 4736{ 4737} 4738#endif 4739 4740static void set_rq_online(struct rq *rq) 4741{ 4742 if (!rq->online) { 4743 const struct sched_class *class; 4744 4745 cpumask_set_cpu(rq->cpu, rq->rd->online); 4746 rq->online = 1; 4747 4748 for_each_class(class) { 4749 if (class->rq_online) 4750 class->rq_online(rq); 4751 } 4752 } 4753} 4754 4755static void set_rq_offline(struct rq *rq) 4756{ 4757 if (rq->online) { 4758 const struct sched_class *class; 4759 4760 for_each_class(class) { 4761 if (class->rq_offline) 4762 class->rq_offline(rq); 4763 } 4764 4765 cpumask_clear_cpu(rq->cpu, rq->rd->online); 4766 rq->online = 0; 4767 } 4768} 4769 4770/* 4771 * migration_call - callback that gets triggered when a CPU is added. 4772 * Here we can start up the necessary migration thread for the new CPU. 4773 */ 4774static int 4775migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) 4776{ 4777 int cpu = (long)hcpu; 4778 unsigned long flags; 4779 struct rq *rq = cpu_rq(cpu); 4780 4781 switch (action & ~CPU_TASKS_FROZEN) { 4782 4783 case CPU_UP_PREPARE: 4784 rq->calc_load_update = calc_load_update; 4785 break; 4786 4787 case CPU_ONLINE: 4788 /* Update our root-domain */ 4789 raw_spin_lock_irqsave(&rq->lock, flags); 4790 if (rq->rd) { 4791 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); 4792 4793 set_rq_online(rq); 4794 } 4795 raw_spin_unlock_irqrestore(&rq->lock, flags); 4796 break; 4797 4798#ifdef CONFIG_HOTPLUG_CPU 4799 case CPU_DYING: 4800 sched_ttwu_pending(); 4801 /* Update our root-domain */ 4802 raw_spin_lock_irqsave(&rq->lock, flags); 4803 if (rq->rd) { 4804 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); 4805 set_rq_offline(rq); 4806 } 4807 migrate_tasks(cpu); 4808 BUG_ON(rq->nr_running != 1); /* the migration thread */ 4809 raw_spin_unlock_irqrestore(&rq->lock, flags); 4810 break; 4811 4812 case CPU_DEAD: 4813 calc_load_migrate(rq); 4814 break; 4815#endif 4816 } 4817 4818 update_max_interval(); 4819 4820 return NOTIFY_OK; 4821} 4822 4823/* 4824 * Register at high priority so that task migration (migrate_all_tasks) 4825 * happens before everything else. This has to be lower priority than 4826 * the notifier in the perf_event subsystem, though. 4827 */ 4828static struct notifier_block migration_notifier = { 4829 .notifier_call = migration_call, 4830 .priority = CPU_PRI_MIGRATION, 4831}; 4832 4833static int sched_cpu_active(struct notifier_block *nfb, 4834 unsigned long action, void *hcpu) 4835{ 4836 switch (action & ~CPU_TASKS_FROZEN) { 4837 case CPU_STARTING: 4838 case CPU_DOWN_FAILED: 4839 set_cpu_active((long)hcpu, true); 4840 return NOTIFY_OK; 4841 default: 4842 return NOTIFY_DONE; 4843 } 4844} 4845 4846static int sched_cpu_inactive(struct notifier_block *nfb, 4847 unsigned long action, void *hcpu) 4848{ 4849 switch (action & ~CPU_TASKS_FROZEN) { 4850 case CPU_DOWN_PREPARE: 4851 set_cpu_active((long)hcpu, false); 4852 return NOTIFY_OK; 4853 default: 4854 return NOTIFY_DONE; 4855 } 4856} 4857 4858static int __init migration_init(void) 4859{ 4860 void *cpu = (void *)(long)smp_processor_id(); 4861 int err; 4862 4863 /* Initialize migration for the boot CPU */ 4864 err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); 4865 BUG_ON(err == NOTIFY_BAD); 4866 migration_call(&migration_notifier, CPU_ONLINE, cpu); 4867 register_cpu_notifier(&migration_notifier); 4868 4869 /* Register cpu active notifiers */ 4870 cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE); 4871 cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE); 4872 4873 return 0; 4874} 4875early_initcall(migration_init); 4876#endif 4877 4878#ifdef CONFIG_SMP 4879 4880static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */ 4881 4882#ifdef CONFIG_SCHED_DEBUG 4883 4884static __read_mostly int sched_debug_enabled; 4885 4886static int __init sched_debug_setup(char *str) 4887{ 4888 sched_debug_enabled = 1; 4889 4890 return 0; 4891} 4892early_param("sched_debug", sched_debug_setup); 4893 4894static inline bool sched_debug(void) 4895{ 4896 return sched_debug_enabled; 4897} 4898 4899static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, 4900 struct cpumask *groupmask) 4901{ 4902 struct sched_group *group = sd->groups; 4903 char str[256]; 4904 4905 cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd)); 4906 cpumask_clear(groupmask); 4907 4908 printk(KERN_DEBUG "%*s domain %d: ", level, "", level); 4909 4910 if (!(sd->flags & SD_LOAD_BALANCE)) { 4911 printk("does not load-balance\n"); 4912 if (sd->parent) 4913 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain" 4914 " has parent"); 4915 return -1; 4916 } 4917 4918 printk(KERN_CONT "span %s level %s\n", str, sd->name); 4919 4920 if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) { 4921 printk(KERN_ERR "ERROR: domain->span does not contain " 4922 "CPU%d\n", cpu); 4923 } 4924 if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) { 4925 printk(KERN_ERR "ERROR: domain->groups does not contain" 4926 " CPU%d\n", cpu); 4927 } 4928 4929 printk(KERN_DEBUG "%*s groups:", level + 1, ""); 4930 do { 4931 if (!group) { 4932 printk("\n"); 4933 printk(KERN_ERR "ERROR: group is NULL\n"); 4934 break; 4935 } 4936 4937 /* 4938 * Even though we initialize ->power to something semi-sane, 4939 * we leave power_orig unset. This allows us to detect if 4940 * domain iteration is still funny without causing /0 traps. 4941 */ 4942 if (!group->sgp->power_orig) { 4943 printk(KERN_CONT "\n"); 4944 printk(KERN_ERR "ERROR: domain->cpu_power not " 4945 "set\n"); 4946 break; 4947 } 4948 4949 if (!cpumask_weight(sched_group_cpus(group))) { 4950 printk(KERN_CONT "\n"); 4951 printk(KERN_ERR "ERROR: empty group\n"); 4952 break; 4953 } 4954 4955 if (!(sd->flags & SD_OVERLAP) && 4956 cpumask_intersects(groupmask, sched_group_cpus(group))) { 4957 printk(KERN_CONT "\n"); 4958 printk(KERN_ERR "ERROR: repeated CPUs\n"); 4959 break; 4960 } 4961 4962 cpumask_or(groupmask, groupmask, sched_group_cpus(group)); 4963 4964 cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group)); 4965 4966 printk(KERN_CONT " %s", str); 4967 if (group->sgp->power != SCHED_POWER_SCALE) { 4968 printk(KERN_CONT " (cpu_power = %d)", 4969 group->sgp->power); 4970 } 4971 4972 group = group->next; 4973 } while (group != sd->groups); 4974 printk(KERN_CONT "\n"); 4975 4976 if (!cpumask_equal(sched_domain_span(sd), groupmask)) 4977 printk(KERN_ERR "ERROR: groups don't span domain->span\n"); 4978 4979 if (sd->parent && 4980 !cpumask_subset(groupmask, sched_domain_span(sd->parent))) 4981 printk(KERN_ERR "ERROR: parent span is not a superset " 4982 "of domain->span\n"); 4983 return 0; 4984} 4985 4986static void sched_domain_debug(struct sched_domain *sd, int cpu) 4987{ 4988 int level = 0; 4989 4990 if (!sched_debug_enabled) 4991 return; 4992 4993 if (!sd) { 4994 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); 4995 return; 4996 } 4997 4998 printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); 4999 5000 for (;;) { 5001 if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask)) 5002 break; 5003 level++; 5004 sd = sd->parent; 5005 if (!sd) 5006 break; 5007 } 5008} 5009#else /* !CONFIG_SCHED_DEBUG */ 5010# define sched_domain_debug(sd, cpu) do { } while (0) 5011static inline bool sched_debug(void) 5012{ 5013 return false; 5014} 5015#endif /* CONFIG_SCHED_DEBUG */ 5016 5017static int sd_degenerate(struct sched_domain *sd) 5018{ 5019 if (cpumask_weight(sched_domain_span(sd)) == 1) 5020 return 1; 5021 5022 /* Following flags need at least 2 groups */ 5023 if (sd->flags & (SD_LOAD_BALANCE | 5024 SD_BALANCE_NEWIDLE | 5025 SD_BALANCE_FORK | 5026 SD_BALANCE_EXEC | 5027 SD_SHARE_CPUPOWER | 5028 SD_SHARE_PKG_RESOURCES)) { 5029 if (sd->groups != sd->groups->next) 5030 return 0; 5031 } 5032 5033 /* Following flags don't use groups */ 5034 if (sd->flags & (SD_WAKE_AFFINE)) 5035 return 0; 5036 5037 return 1; 5038} 5039 5040static int 5041sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) 5042{ 5043 unsigned long cflags = sd->flags, pflags = parent->flags; 5044 5045 if (sd_degenerate(parent)) 5046 return 1; 5047 5048 if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent))) 5049 return 0; 5050 5051 /* Flags needing groups don't count if only 1 group in parent */ 5052 if (parent->groups == parent->groups->next) { 5053 pflags &= ~(SD_LOAD_BALANCE | 5054 SD_BALANCE_NEWIDLE | 5055 SD_BALANCE_FORK | 5056 SD_BALANCE_EXEC | 5057 SD_SHARE_CPUPOWER | 5058 SD_SHARE_PKG_RESOURCES | 5059 SD_PREFER_SIBLING); 5060 if (nr_node_ids == 1) 5061 pflags &= ~SD_SERIALIZE; 5062 } 5063 if (~cflags & pflags) 5064 return 0; 5065 5066 return 1; 5067} 5068 5069static void free_rootdomain(struct rcu_head *rcu) 5070{ 5071 struct root_domain *rd = container_of(rcu, struct root_domain, rcu); 5072 5073 cpupri_cleanup(&rd->cpupri); 5074 free_cpumask_var(rd->dlo_mask); 5075 free_cpumask_var(rd->rto_mask); 5076 free_cpumask_var(rd->online); 5077 free_cpumask_var(rd->span); 5078 kfree(rd); 5079} 5080 5081static void rq_attach_root(struct rq *rq, struct root_domain *rd) 5082{ 5083 struct root_domain *old_rd = NULL; 5084 unsigned long flags; 5085 5086 raw_spin_lock_irqsave(&rq->lock, flags); 5087 5088 if (rq->rd) { 5089 old_rd = rq->rd; 5090 5091 if (cpumask_test_cpu(rq->cpu, old_rd->online)) 5092 set_rq_offline(rq); 5093 5094 cpumask_clear_cpu(rq->cpu, old_rd->span); 5095 5096 /* 5097 * If we dont want to free the old_rd yet then 5098 * set old_rd to NULL to skip the freeing later 5099 * in this function: 5100 */ 5101 if (!atomic_dec_and_test(&old_rd->refcount)) 5102 old_rd = NULL; 5103 } 5104 5105 atomic_inc(&rd->refcount); 5106 rq->rd = rd; 5107 5108 cpumask_set_cpu(rq->cpu, rd->span); 5109 if (cpumask_test_cpu(rq->cpu, cpu_active_mask)) 5110 set_rq_online(rq); 5111 5112 raw_spin_unlock_irqrestore(&rq->lock, flags); 5113 5114 if (old_rd) 5115 call_rcu_sched(&old_rd->rcu, free_rootdomain); 5116} 5117 5118static int init_rootdomain(struct root_domain *rd) 5119{ 5120 memset(rd, 0, sizeof(*rd)); 5121 5122 if (!alloc_cpumask_var(&rd->span, GFP_KERNEL)) 5123 goto out; 5124 if (!alloc_cpumask_var(&rd->online, GFP_KERNEL)) 5125 goto free_span; 5126 if (!alloc_cpumask_var(&rd->dlo_mask, GFP_KERNEL)) 5127 goto free_online; 5128 if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL)) 5129 goto free_dlo_mask; 5130 5131 if (cpupri_init(&rd->cpupri) != 0) 5132 goto free_rto_mask; 5133 return 0; 5134 5135free_rto_mask: 5136 free_cpumask_var(rd->rto_mask); 5137free_dlo_mask: 5138 free_cpumask_var(rd->dlo_mask); 5139free_online: 5140 free_cpumask_var(rd->online); 5141free_span: 5142 free_cpumask_var(rd->span); 5143out: 5144 return -ENOMEM; 5145} 5146 5147/* 5148 * By default the system creates a single root-domain with all cpus as 5149 * members (mimicking the global state we have today). 5150 */ 5151struct root_domain def_root_domain; 5152 5153static void init_defrootdomain(void) 5154{ 5155 init_rootdomain(&def_root_domain); 5156 5157 atomic_set(&def_root_domain.refcount, 1); 5158} 5159 5160static struct root_domain *alloc_rootdomain(void) 5161{ 5162 struct root_domain *rd; 5163 5164 rd = kmalloc(sizeof(*rd), GFP_KERNEL); 5165 if (!rd) 5166 return NULL; 5167 5168 if (init_rootdomain(rd) != 0) { 5169 kfree(rd); 5170 return NULL; 5171 } 5172 5173 return rd; 5174} 5175 5176static void free_sched_groups(struct sched_group *sg, int free_sgp) 5177{ 5178 struct sched_group *tmp, *first; 5179 5180 if (!sg) 5181 return; 5182 5183 first = sg; 5184 do { 5185 tmp = sg->next; 5186 5187 if (free_sgp && atomic_dec_and_test(&sg->sgp->ref)) 5188 kfree(sg->sgp); 5189 5190 kfree(sg); 5191 sg = tmp; 5192 } while (sg != first); 5193} 5194 5195static void free_sched_domain(struct rcu_head *rcu) 5196{ 5197 struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu); 5198 5199 /* 5200 * If its an overlapping domain it has private groups, iterate and 5201 * nuke them all. 5202 */ 5203 if (sd->flags & SD_OVERLAP) { 5204 free_sched_groups(sd->groups, 1); 5205 } else if (atomic_dec_and_test(&sd->groups->ref)) { 5206 kfree(sd->groups->sgp); 5207 kfree(sd->groups); 5208 } 5209 kfree(sd); 5210} 5211 5212static void destroy_sched_domain(struct sched_domain *sd, int cpu) 5213{ 5214 call_rcu(&sd->rcu, free_sched_domain); 5215} 5216 5217static void destroy_sched_domains(struct sched_domain *sd, int cpu) 5218{ 5219 for (; sd; sd = sd->parent) 5220 destroy_sched_domain(sd, cpu); 5221} 5222 5223/* 5224 * Keep a special pointer to the highest sched_domain that has 5225 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this 5226 * allows us to avoid some pointer chasing select_idle_sibling(). 5227 * 5228 * Also keep a unique ID per domain (we use the first cpu number in 5229 * the cpumask of the domain), this allows us to quickly tell if 5230 * two cpus are in the same cache domain, see cpus_share_cache(). 5231 */ 5232DEFINE_PER_CPU(struct sched_domain *, sd_llc); 5233DEFINE_PER_CPU(int, sd_llc_size); 5234DEFINE_PER_CPU(int, sd_llc_id); 5235DEFINE_PER_CPU(struct sched_domain *, sd_numa); 5236DEFINE_PER_CPU(struct sched_domain *, sd_busy); 5237DEFINE_PER_CPU(struct sched_domain *, sd_asym); 5238 5239static void update_top_cache_domain(int cpu) 5240{ 5241 struct sched_domain *sd; 5242 struct sched_domain *busy_sd = NULL; 5243 int id = cpu; 5244 int size = 1; 5245 5246 sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES); 5247 if (sd) { 5248 id = cpumask_first(sched_domain_span(sd)); 5249 size = cpumask_weight(sched_domain_span(sd)); 5250 busy_sd = sd->parent; /* sd_busy */ 5251 } 5252 rcu_assign_pointer(per_cpu(sd_busy, cpu), busy_sd); 5253 5254 rcu_assign_pointer(per_cpu(sd_llc, cpu), sd); 5255 per_cpu(sd_llc_size, cpu) = size; 5256 per_cpu(sd_llc_id, cpu) = id; 5257 5258 sd = lowest_flag_domain(cpu, SD_NUMA); 5259 rcu_assign_pointer(per_cpu(sd_numa, cpu), sd); 5260 5261 sd = highest_flag_domain(cpu, SD_ASYM_PACKING); 5262 rcu_assign_pointer(per_cpu(sd_asym, cpu), sd); 5263} 5264 5265/* 5266 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must 5267 * hold the hotplug lock. 5268 */ 5269static void 5270cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) 5271{ 5272 struct rq *rq = cpu_rq(cpu); 5273 struct sched_domain *tmp; 5274 5275 /* Remove the sched domains which do not contribute to scheduling. */ 5276 for (tmp = sd; tmp; ) { 5277 struct sched_domain *parent = tmp->parent; 5278 if (!parent) 5279 break; 5280 5281 if (sd_parent_degenerate(tmp, parent)) { 5282 tmp->parent = parent->parent; 5283 if (parent->parent) 5284 parent->parent->child = tmp; 5285 /* 5286 * Transfer SD_PREFER_SIBLING down in case of a 5287 * degenerate parent; the spans match for this 5288 * so the property transfers. 5289 */ 5290 if (parent->flags & SD_PREFER_SIBLING) 5291 tmp->flags |= SD_PREFER_SIBLING; 5292 destroy_sched_domain(parent, cpu); 5293 } else 5294 tmp = tmp->parent; 5295 } 5296 5297 if (sd && sd_degenerate(sd)) { 5298 tmp = sd; 5299 sd = sd->parent; 5300 destroy_sched_domain(tmp, cpu); 5301 if (sd) 5302 sd->child = NULL; 5303 } 5304 5305 sched_domain_debug(sd, cpu); 5306 5307 rq_attach_root(rq, rd); 5308 tmp = rq->sd; 5309 rcu_assign_pointer(rq->sd, sd); 5310 destroy_sched_domains(tmp, cpu); 5311 5312 update_top_cache_domain(cpu); 5313} 5314 5315/* cpus with isolated domains */ 5316static cpumask_var_t cpu_isolated_map; 5317 5318/* Setup the mask of cpus configured for isolated domains */ 5319static int __init isolated_cpu_setup(char *str) 5320{ 5321 alloc_bootmem_cpumask_var(&cpu_isolated_map); 5322 cpulist_parse(str, cpu_isolated_map); 5323 return 1; 5324} 5325 5326__setup("isolcpus=", isolated_cpu_setup); 5327 5328static const struct cpumask *cpu_cpu_mask(int cpu) 5329{ 5330 return cpumask_of_node(cpu_to_node(cpu)); 5331} 5332 5333struct sd_data { 5334 struct sched_domain **__percpu sd; 5335 struct sched_group **__percpu sg; 5336 struct sched_group_power **__percpu sgp; 5337}; 5338 5339struct s_data { 5340 struct sched_domain ** __percpu sd; 5341 struct root_domain *rd; 5342}; 5343 5344enum s_alloc { 5345 sa_rootdomain, 5346 sa_sd, 5347 sa_sd_storage, 5348 sa_none, 5349}; 5350 5351struct sched_domain_topology_level; 5352 5353typedef struct sched_domain *(*sched_domain_init_f)(struct sched_domain_topology_level *tl, int cpu); 5354typedef const struct cpumask *(*sched_domain_mask_f)(int cpu); 5355 5356#define SDTL_OVERLAP 0x01 5357 5358struct sched_domain_topology_level { 5359 sched_domain_init_f init; 5360 sched_domain_mask_f mask; 5361 int flags; 5362 int numa_level; 5363 struct sd_data data; 5364}; 5365 5366/* 5367 * Build an iteration mask that can exclude certain CPUs from the upwards 5368 * domain traversal. 5369 * 5370 * Asymmetric node setups can result in situations where the domain tree is of 5371 * unequal depth, make sure to skip domains that already cover the entire 5372 * range. 5373 * 5374 * In that case build_sched_domains() will have terminated the iteration early 5375 * and our sibling sd spans will be empty. Domains should always include the 5376 * cpu they're built on, so check that. 5377 * 5378 */ 5379static void build_group_mask(struct sched_domain *sd, struct sched_group *sg) 5380{ 5381 const struct cpumask *span = sched_domain_span(sd); 5382 struct sd_data *sdd = sd->private; 5383 struct sched_domain *sibling; 5384 int i; 5385 5386 for_each_cpu(i, span) { 5387 sibling = *per_cpu_ptr(sdd->sd, i); 5388 if (!cpumask_test_cpu(i, sched_domain_span(sibling))) 5389 continue; 5390 5391 cpumask_set_cpu(i, sched_group_mask(sg)); 5392 } 5393} 5394 5395/* 5396 * Return the canonical balance cpu for this group, this is the first cpu 5397 * of this group that's also in the iteration mask. 5398 */ 5399int group_balance_cpu(struct sched_group *sg) 5400{ 5401 return cpumask_first_and(sched_group_cpus(sg), sched_group_mask(sg)); 5402} 5403 5404static int 5405build_overlap_sched_groups(struct sched_domain *sd, int cpu) 5406{ 5407 struct sched_group *first = NULL, *last = NULL, *groups = NULL, *sg; 5408 const struct cpumask *span = sched_domain_span(sd); 5409 struct cpumask *covered = sched_domains_tmpmask; 5410 struct sd_data *sdd = sd->private; 5411 struct sched_domain *child; 5412 int i; 5413 5414 cpumask_clear(covered); 5415 5416 for_each_cpu(i, span) { 5417 struct cpumask *sg_span; 5418 5419 if (cpumask_test_cpu(i, covered)) 5420 continue; 5421 5422 child = *per_cpu_ptr(sdd->sd, i); 5423 5424 /* See the comment near build_group_mask(). */ 5425 if (!cpumask_test_cpu(i, sched_domain_span(child))) 5426 continue; 5427 5428 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), 5429 GFP_KERNEL, cpu_to_node(cpu)); 5430 5431 if (!sg) 5432 goto fail; 5433 5434 sg_span = sched_group_cpus(sg); 5435 if (child->child) { 5436 child = child->child; 5437 cpumask_copy(sg_span, sched_domain_span(child)); 5438 } else 5439 cpumask_set_cpu(i, sg_span); 5440 5441 cpumask_or(covered, covered, sg_span); 5442 5443 sg->sgp = *per_cpu_ptr(sdd->sgp, i); 5444 if (atomic_inc_return(&sg->sgp->ref) == 1) 5445 build_group_mask(sd, sg); 5446 5447 /* 5448 * Initialize sgp->power such that even if we mess up the 5449 * domains and no possible iteration will get us here, we won't 5450 * die on a /0 trap. 5451 */ 5452 sg->sgp->power = SCHED_POWER_SCALE * cpumask_weight(sg_span); 5453 sg->sgp->power_orig = sg->sgp->power; 5454 5455 /* 5456 * Make sure the first group of this domain contains the 5457 * canonical balance cpu. Otherwise the sched_domain iteration 5458 * breaks. See update_sg_lb_stats(). 5459 */ 5460 if ((!groups && cpumask_test_cpu(cpu, sg_span)) || 5461 group_balance_cpu(sg) == cpu) 5462 groups = sg; 5463 5464 if (!first) 5465 first = sg; 5466 if (last) 5467 last->next = sg; 5468 last = sg; 5469 last->next = first; 5470 } 5471 sd->groups = groups; 5472 5473 return 0; 5474 5475fail: 5476 free_sched_groups(first, 0); 5477 5478 return -ENOMEM; 5479} 5480 5481static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg) 5482{ 5483 struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu); 5484 struct sched_domain *child = sd->child; 5485 5486 if (child) 5487 cpu = cpumask_first(sched_domain_span(child)); 5488 5489 if (sg) { 5490 *sg = *per_cpu_ptr(sdd->sg, cpu); 5491 (*sg)->sgp = *per_cpu_ptr(sdd->sgp, cpu); 5492 atomic_set(&(*sg)->sgp->ref, 1); /* for claim_allocations */ 5493 } 5494 5495 return cpu; 5496} 5497 5498/* 5499 * build_sched_groups will build a circular linked list of the groups 5500 * covered by the given span, and will set each group's ->cpumask correctly, 5501 * and ->cpu_power to 0. 5502 * 5503 * Assumes the sched_domain tree is fully constructed 5504 */ 5505static int 5506build_sched_groups(struct sched_domain *sd, int cpu) 5507{ 5508 struct sched_group *first = NULL, *last = NULL; 5509 struct sd_data *sdd = sd->private; 5510 const struct cpumask *span = sched_domain_span(sd); 5511 struct cpumask *covered; 5512 int i; 5513 5514 get_group(cpu, sdd, &sd->groups); 5515 atomic_inc(&sd->groups->ref); 5516 5517 if (cpu != cpumask_first(span)) 5518 return 0; 5519 5520 lockdep_assert_held(&sched_domains_mutex); 5521 covered = sched_domains_tmpmask; 5522 5523 cpumask_clear(covered); 5524 5525 for_each_cpu(i, span) { 5526 struct sched_group *sg; 5527 int group, j; 5528 5529 if (cpumask_test_cpu(i, covered)) 5530 continue; 5531 5532 group = get_group(i, sdd, &sg); 5533 cpumask_clear(sched_group_cpus(sg)); 5534 sg->sgp->power = 0; 5535 cpumask_setall(sched_group_mask(sg)); 5536 5537 for_each_cpu(j, span) { 5538 if (get_group(j, sdd, NULL) != group) 5539 continue; 5540 5541 cpumask_set_cpu(j, covered); 5542 cpumask_set_cpu(j, sched_group_cpus(sg)); 5543 } 5544 5545 if (!first) 5546 first = sg; 5547 if (last) 5548 last->next = sg; 5549 last = sg; 5550 } 5551 last->next = first; 5552 5553 return 0; 5554} 5555 5556/* 5557 * Initialize sched groups cpu_power. 5558 * 5559 * cpu_power indicates the capacity of sched group, which is used while 5560 * distributing the load between different sched groups in a sched domain. 5561 * Typically cpu_power for all the groups in a sched domain will be same unless 5562 * there are asymmetries in the topology. If there are asymmetries, group 5563 * having more cpu_power will pickup more load compared to the group having 5564 * less cpu_power. 5565 */ 5566static void init_sched_groups_power(int cpu, struct sched_domain *sd) 5567{ 5568 struct sched_group *sg = sd->groups; 5569 5570 WARN_ON(!sg); 5571 5572 do { 5573 sg->group_weight = cpumask_weight(sched_group_cpus(sg)); 5574 sg = sg->next; 5575 } while (sg != sd->groups); 5576 5577 if (cpu != group_balance_cpu(sg)) 5578 return; 5579 5580 update_group_power(sd, cpu); 5581 atomic_set(&sg->sgp->nr_busy_cpus, sg->group_weight); 5582} 5583 5584int __weak arch_sd_sibling_asym_packing(void) 5585{ 5586 return 0*SD_ASYM_PACKING; 5587} 5588 5589/* 5590 * Initializers for schedule domains 5591 * Non-inlined to reduce accumulated stack pressure in build_sched_domains() 5592 */ 5593 5594#ifdef CONFIG_SCHED_DEBUG 5595# define SD_INIT_NAME(sd, type) sd->name = #type 5596#else 5597# define SD_INIT_NAME(sd, type) do { } while (0) 5598#endif 5599 5600#define SD_INIT_FUNC(type) \ 5601static noinline struct sched_domain * \ 5602sd_init_##type(struct sched_domain_topology_level *tl, int cpu) \ 5603{ \ 5604 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); \ 5605 *sd = SD_##type##_INIT; \ 5606 SD_INIT_NAME(sd, type); \ 5607 sd->private = &tl->data; \ 5608 return sd; \ 5609} 5610 5611SD_INIT_FUNC(CPU) 5612#ifdef CONFIG_SCHED_SMT 5613 SD_INIT_FUNC(SIBLING) 5614#endif 5615#ifdef CONFIG_SCHED_MC 5616 SD_INIT_FUNC(MC) 5617#endif 5618#ifdef CONFIG_SCHED_BOOK 5619 SD_INIT_FUNC(BOOK) 5620#endif 5621 5622static int default_relax_domain_level = -1; 5623int sched_domain_level_max; 5624 5625static int __init setup_relax_domain_level(char *str) 5626{ 5627 if (kstrtoint(str, 0, &default_relax_domain_level)) 5628 pr_warn("Unable to set relax_domain_level\n"); 5629 5630 return 1; 5631} 5632__setup("relax_domain_level=", setup_relax_domain_level); 5633 5634static void set_domain_attribute(struct sched_domain *sd, 5635 struct sched_domain_attr *attr) 5636{ 5637 int request; 5638 5639 if (!attr || attr->relax_domain_level < 0) { 5640 if (default_relax_domain_level < 0) 5641 return; 5642 else 5643 request = default_relax_domain_level; 5644 } else 5645 request = attr->relax_domain_level; 5646 if (request < sd->level) { 5647 /* turn off idle balance on this domain */ 5648 sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); 5649 } else { 5650 /* turn on idle balance on this domain */ 5651 sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); 5652 } 5653} 5654 5655static void __sdt_free(const struct cpumask *cpu_map); 5656static int __sdt_alloc(const struct cpumask *cpu_map); 5657 5658static void __free_domain_allocs(struct s_data *d, enum s_alloc what, 5659 const struct cpumask *cpu_map) 5660{ 5661 switch (what) { 5662 case sa_rootdomain: 5663 if (!atomic_read(&d->rd->refcount)) 5664 free_rootdomain(&d->rd->rcu); /* fall through */ 5665 case sa_sd: 5666 free_percpu(d->sd); /* fall through */ 5667 case sa_sd_storage: 5668 __sdt_free(cpu_map); /* fall through */ 5669 case sa_none: 5670 break; 5671 } 5672} 5673 5674static enum s_alloc __visit_domain_allocation_hell(struct s_data *d, 5675 const struct cpumask *cpu_map) 5676{ 5677 memset(d, 0, sizeof(*d)); 5678 5679 if (__sdt_alloc(cpu_map)) 5680 return sa_sd_storage; 5681 d->sd = alloc_percpu(struct sched_domain *); 5682 if (!d->sd) 5683 return sa_sd_storage; 5684 d->rd = alloc_rootdomain(); 5685 if (!d->rd) 5686 return sa_sd; 5687 return sa_rootdomain; 5688} 5689 5690/* 5691 * NULL the sd_data elements we've used to build the sched_domain and 5692 * sched_group structure so that the subsequent __free_domain_allocs() 5693 * will not free the data we're using. 5694 */ 5695static void claim_allocations(int cpu, struct sched_domain *sd) 5696{ 5697 struct sd_data *sdd = sd->private; 5698 5699 WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd); 5700 *per_cpu_ptr(sdd->sd, cpu) = NULL; 5701 5702 if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref)) 5703 *per_cpu_ptr(sdd->sg, cpu) = NULL; 5704 5705 if (atomic_read(&(*per_cpu_ptr(sdd->sgp, cpu))->ref)) 5706 *per_cpu_ptr(sdd->sgp, cpu) = NULL; 5707} 5708 5709#ifdef CONFIG_SCHED_SMT 5710static const struct cpumask *cpu_smt_mask(int cpu) 5711{ 5712 return topology_thread_cpumask(cpu); 5713} 5714#endif 5715 5716/* 5717 * Topology list, bottom-up. 5718 */ 5719static struct sched_domain_topology_level default_topology[] = { 5720#ifdef CONFIG_SCHED_SMT 5721 { sd_init_SIBLING, cpu_smt_mask, }, 5722#endif 5723#ifdef CONFIG_SCHED_MC 5724 { sd_init_MC, cpu_coregroup_mask, }, 5725#endif 5726#ifdef CONFIG_SCHED_BOOK 5727 { sd_init_BOOK, cpu_book_mask, }, 5728#endif 5729 { sd_init_CPU, cpu_cpu_mask, }, 5730 { NULL, }, 5731}; 5732 5733static struct sched_domain_topology_level *sched_domain_topology = default_topology; 5734 5735#define for_each_sd_topology(tl) \ 5736 for (tl = sched_domain_topology; tl->init; tl++) 5737 5738#ifdef CONFIG_NUMA 5739 5740static int sched_domains_numa_levels; 5741static int *sched_domains_numa_distance; 5742static struct cpumask ***sched_domains_numa_masks; 5743static int sched_domains_curr_level; 5744 5745static inline int sd_local_flags(int level) 5746{ 5747 if (sched_domains_numa_distance[level] > RECLAIM_DISTANCE) 5748 return 0; 5749 5750 return SD_BALANCE_EXEC | SD_BALANCE_FORK | SD_WAKE_AFFINE; 5751} 5752 5753static struct sched_domain * 5754sd_numa_init(struct sched_domain_topology_level *tl, int cpu) 5755{ 5756 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); 5757 int level = tl->numa_level; 5758 int sd_weight = cpumask_weight( 5759 sched_domains_numa_masks[level][cpu_to_node(cpu)]); 5760 5761 *sd = (struct sched_domain){ 5762 .min_interval = sd_weight, 5763 .max_interval = 2*sd_weight, 5764 .busy_factor = 32, 5765 .imbalance_pct = 125, 5766 .cache_nice_tries = 2, 5767 .busy_idx = 3, 5768 .idle_idx = 2, 5769 .newidle_idx = 0, 5770 .wake_idx = 0, 5771 .forkexec_idx = 0, 5772 5773 .flags = 1*SD_LOAD_BALANCE 5774 | 1*SD_BALANCE_NEWIDLE 5775 | 0*SD_BALANCE_EXEC 5776 | 0*SD_BALANCE_FORK 5777 | 0*SD_BALANCE_WAKE 5778 | 0*SD_WAKE_AFFINE 5779 | 0*SD_SHARE_CPUPOWER 5780 | 0*SD_SHARE_PKG_RESOURCES 5781 | 1*SD_SERIALIZE 5782 | 0*SD_PREFER_SIBLING 5783 | 1*SD_NUMA 5784 | sd_local_flags(level) 5785 , 5786 .last_balance = jiffies, 5787 .balance_interval = sd_weight, 5788 }; 5789 SD_INIT_NAME(sd, NUMA); 5790 sd->private = &tl->data; 5791 5792 /* 5793 * Ugly hack to pass state to sd_numa_mask()... 5794 */ 5795 sched_domains_curr_level = tl->numa_level; 5796 5797 return sd; 5798} 5799 5800static const struct cpumask *sd_numa_mask(int cpu) 5801{ 5802 return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)]; 5803} 5804 5805static void sched_numa_warn(const char *str) 5806{ 5807 static int done = false; 5808 int i,j; 5809 5810 if (done) 5811 return; 5812 5813 done = true; 5814 5815 printk(KERN_WARNING "ERROR: %s\n\n", str); 5816 5817 for (i = 0; i < nr_node_ids; i++) { 5818 printk(KERN_WARNING " "); 5819 for (j = 0; j < nr_node_ids; j++) 5820 printk(KERN_CONT "%02d ", node_distance(i,j)); 5821 printk(KERN_CONT "\n"); 5822 } 5823 printk(KERN_WARNING "\n"); 5824} 5825 5826static bool find_numa_distance(int distance) 5827{ 5828 int i; 5829 5830 if (distance == node_distance(0, 0)) 5831 return true; 5832 5833 for (i = 0; i < sched_domains_numa_levels; i++) { 5834 if (sched_domains_numa_distance[i] == distance) 5835 return true; 5836 } 5837 5838 return false; 5839} 5840 5841static void sched_init_numa(void) 5842{ 5843 int next_distance, curr_distance = node_distance(0, 0); 5844 struct sched_domain_topology_level *tl; 5845 int level = 0; 5846 int i, j, k; 5847 5848 sched_domains_numa_distance = kzalloc(sizeof(int) * nr_node_ids, GFP_KERNEL); 5849 if (!sched_domains_numa_distance) 5850 return; 5851 5852 /* 5853 * O(nr_nodes^2) deduplicating selection sort -- in order to find the 5854 * unique distances in the node_distance() table. 5855 * 5856 * Assumes node_distance(0,j) includes all distances in 5857 * node_distance(i,j) in order to avoid cubic time. 5858 */ 5859 next_distance = curr_distance; 5860 for (i = 0; i < nr_node_ids; i++) { 5861 for (j = 0; j < nr_node_ids; j++) { 5862 for (k = 0; k < nr_node_ids; k++) { 5863 int distance = node_distance(i, k); 5864 5865 if (distance > curr_distance && 5866 (distance < next_distance || 5867 next_distance == curr_distance)) 5868 next_distance = distance; 5869 5870 /* 5871 * While not a strong assumption it would be nice to know 5872 * about cases where if node A is connected to B, B is not 5873 * equally connected to A. 5874 */ 5875 if (sched_debug() && node_distance(k, i) != distance) 5876 sched_numa_warn("Node-distance not symmetric"); 5877 5878 if (sched_debug() && i && !find_numa_distance(distance)) 5879 sched_numa_warn("Node-0 not representative"); 5880 } 5881 if (next_distance != curr_distance) { 5882 sched_domains_numa_distance[level++] = next_distance; 5883 sched_domains_numa_levels = level; 5884 curr_distance = next_distance; 5885 } else break; 5886 } 5887 5888 /* 5889 * In case of sched_debug() we verify the above assumption. 5890 */ 5891 if (!sched_debug()) 5892 break; 5893 } 5894 /* 5895 * 'level' contains the number of unique distances, excluding the 5896 * identity distance node_distance(i,i). 5897 * 5898 * The sched_domains_numa_distance[] array includes the actual distance 5899 * numbers. 5900 */ 5901 5902 /* 5903 * Here, we should temporarily reset sched_domains_numa_levels to 0. 5904 * If it fails to allocate memory for array sched_domains_numa_masks[][], 5905 * the array will contain less then 'level' members. This could be 5906 * dangerous when we use it to iterate array sched_domains_numa_masks[][] 5907 * in other functions. 5908 * 5909 * We reset it to 'level' at the end of this function. 5910 */ 5911 sched_domains_numa_levels = 0; 5912 5913 sched_domains_numa_masks = kzalloc(sizeof(void *) * level, GFP_KERNEL); 5914 if (!sched_domains_numa_masks) 5915 return; 5916 5917 /* 5918 * Now for each level, construct a mask per node which contains all 5919 * cpus of nodes that are that many hops away from us. 5920 */ 5921 for (i = 0; i < level; i++) { 5922 sched_domains_numa_masks[i] = 5923 kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL); 5924 if (!sched_domains_numa_masks[i]) 5925 return; 5926 5927 for (j = 0; j < nr_node_ids; j++) { 5928 struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL); 5929 if (!mask) 5930 return; 5931 5932 sched_domains_numa_masks[i][j] = mask; 5933 5934 for (k = 0; k < nr_node_ids; k++) { 5935 if (node_distance(j, k) > sched_domains_numa_distance[i]) 5936 continue; 5937 5938 cpumask_or(mask, mask, cpumask_of_node(k)); 5939 } 5940 } 5941 } 5942 5943 tl = kzalloc((ARRAY_SIZE(default_topology) + level) * 5944 sizeof(struct sched_domain_topology_level), GFP_KERNEL); 5945 if (!tl) 5946 return; 5947 5948 /* 5949 * Copy the default topology bits.. 5950 */ 5951 for (i = 0; default_topology[i].init; i++) 5952 tl[i] = default_topology[i]; 5953 5954 /* 5955 * .. and append 'j' levels of NUMA goodness. 5956 */ 5957 for (j = 0; j < level; i++, j++) { 5958 tl[i] = (struct sched_domain_topology_level){ 5959 .init = sd_numa_init, 5960 .mask = sd_numa_mask, 5961 .flags = SDTL_OVERLAP, 5962 .numa_level = j, 5963 }; 5964 } 5965 5966 sched_domain_topology = tl; 5967 5968 sched_domains_numa_levels = level; 5969} 5970 5971static void sched_domains_numa_masks_set(int cpu) 5972{ 5973 int i, j; 5974 int node = cpu_to_node(cpu); 5975 5976 for (i = 0; i < sched_domains_numa_levels; i++) { 5977 for (j = 0; j < nr_node_ids; j++) { 5978 if (node_distance(j, node) <= sched_domains_numa_distance[i]) 5979 cpumask_set_cpu(cpu, sched_domains_numa_masks[i][j]); 5980 } 5981 } 5982} 5983 5984static void sched_domains_numa_masks_clear(int cpu) 5985{ 5986 int i, j; 5987 for (i = 0; i < sched_domains_numa_levels; i++) { 5988 for (j = 0; j < nr_node_ids; j++) 5989 cpumask_clear_cpu(cpu, sched_domains_numa_masks[i][j]); 5990 } 5991} 5992 5993/* 5994 * Update sched_domains_numa_masks[level][node] array when new cpus 5995 * are onlined. 5996 */ 5997static int sched_domains_numa_masks_update(struct notifier_block *nfb, 5998 unsigned long action, 5999 void *hcpu) 6000{ 6001 int cpu = (long)hcpu; 6002 6003 switch (action & ~CPU_TASKS_FROZEN) { 6004 case CPU_ONLINE: 6005 sched_domains_numa_masks_set(cpu); 6006 break; 6007 6008 case CPU_DEAD: 6009 sched_domains_numa_masks_clear(cpu); 6010 break; 6011 6012 default: 6013 return NOTIFY_DONE; 6014 } 6015 6016 return NOTIFY_OK; 6017} 6018#else 6019static inline void sched_init_numa(void) 6020{ 6021} 6022 6023static int sched_domains_numa_masks_update(struct notifier_block *nfb, 6024 unsigned long action, 6025 void *hcpu) 6026{ 6027 return 0; 6028} 6029#endif /* CONFIG_NUMA */ 6030 6031static int __sdt_alloc(const struct cpumask *cpu_map) 6032{ 6033 struct sched_domain_topology_level *tl; 6034 int j; 6035 6036 for_each_sd_topology(tl) { 6037 struct sd_data *sdd = &tl->data; 6038 6039 sdd->sd = alloc_percpu(struct sched_domain *); 6040 if (!sdd->sd) 6041 return -ENOMEM; 6042 6043 sdd->sg = alloc_percpu(struct sched_group *); 6044 if (!sdd->sg) 6045 return -ENOMEM; 6046 6047 sdd->sgp = alloc_percpu(struct sched_group_power *); 6048 if (!sdd->sgp) 6049 return -ENOMEM; 6050 6051 for_each_cpu(j, cpu_map) { 6052 struct sched_domain *sd; 6053 struct sched_group *sg; 6054 struct sched_group_power *sgp; 6055 6056 sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(), 6057 GFP_KERNEL, cpu_to_node(j)); 6058 if (!sd) 6059 return -ENOMEM; 6060 6061 *per_cpu_ptr(sdd->sd, j) = sd; 6062 6063 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), 6064 GFP_KERNEL, cpu_to_node(j)); 6065 if (!sg) 6066 return -ENOMEM; 6067 6068 sg->next = sg; 6069 6070 *per_cpu_ptr(sdd->sg, j) = sg; 6071 6072 sgp = kzalloc_node(sizeof(struct sched_group_power) + cpumask_size(), 6073 GFP_KERNEL, cpu_to_node(j)); 6074 if (!sgp) 6075 return -ENOMEM; 6076 6077 *per_cpu_ptr(sdd->sgp, j) = sgp; 6078 } 6079 } 6080 6081 return 0; 6082} 6083 6084static void __sdt_free(const struct cpumask *cpu_map) 6085{ 6086 struct sched_domain_topology_level *tl; 6087 int j; 6088 6089 for_each_sd_topology(tl) { 6090 struct sd_data *sdd = &tl->data; 6091 6092 for_each_cpu(j, cpu_map) { 6093 struct sched_domain *sd; 6094 6095 if (sdd->sd) { 6096 sd = *per_cpu_ptr(sdd->sd, j); 6097 if (sd && (sd->flags & SD_OVERLAP)) 6098 free_sched_groups(sd->groups, 0); 6099 kfree(*per_cpu_ptr(sdd->sd, j)); 6100 } 6101 6102 if (sdd->sg) 6103 kfree(*per_cpu_ptr(sdd->sg, j)); 6104 if (sdd->sgp) 6105 kfree(*per_cpu_ptr(sdd->sgp, j)); 6106 } 6107 free_percpu(sdd->sd); 6108 sdd->sd = NULL; 6109 free_percpu(sdd->sg); 6110 sdd->sg = NULL; 6111 free_percpu(sdd->sgp); 6112 sdd->sgp = NULL; 6113 } 6114} 6115 6116struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl, 6117 const struct cpumask *cpu_map, struct sched_domain_attr *attr, 6118 struct sched_domain *child, int cpu) 6119{ 6120 struct sched_domain *sd = tl->init(tl, cpu); 6121 if (!sd) 6122 return child; 6123 6124 cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu)); 6125 if (child) { 6126 sd->level = child->level + 1; 6127 sched_domain_level_max = max(sched_domain_level_max, sd->level); 6128 child->parent = sd; 6129 sd->child = child; 6130 } 6131 set_domain_attribute(sd, attr); 6132 6133 return sd; 6134} 6135 6136/* 6137 * Build sched domains for a given set of cpus and attach the sched domains 6138 * to the individual cpus 6139 */ 6140static int build_sched_domains(const struct cpumask *cpu_map, 6141 struct sched_domain_attr *attr) 6142{ 6143 enum s_alloc alloc_state; 6144 struct sched_domain *sd; 6145 struct s_data d; 6146 int i, ret = -ENOMEM; 6147 6148 alloc_state = __visit_domain_allocation_hell(&d, cpu_map); 6149 if (alloc_state != sa_rootdomain) 6150 goto error; 6151 6152 /* Set up domains for cpus specified by the cpu_map. */ 6153 for_each_cpu(i, cpu_map) { 6154 struct sched_domain_topology_level *tl; 6155 6156 sd = NULL; 6157 for_each_sd_topology(tl) { 6158 sd = build_sched_domain(tl, cpu_map, attr, sd, i); 6159 if (tl == sched_domain_topology) 6160 *per_cpu_ptr(d.sd, i) = sd; 6161 if (tl->flags & SDTL_OVERLAP || sched_feat(FORCE_SD_OVERLAP)) 6162 sd->flags |= SD_OVERLAP; 6163 if (cpumask_equal(cpu_map, sched_domain_span(sd))) 6164 break; 6165 } 6166 } 6167 6168 /* Build the groups for the domains */ 6169 for_each_cpu(i, cpu_map) { 6170 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { 6171 sd->span_weight = cpumask_weight(sched_domain_span(sd)); 6172 if (sd->flags & SD_OVERLAP) { 6173 if (build_overlap_sched_groups(sd, i)) 6174 goto error; 6175 } else { 6176 if (build_sched_groups(sd, i)) 6177 goto error; 6178 } 6179 } 6180 } 6181 6182 /* Calculate CPU power for physical packages and nodes */ 6183 for (i = nr_cpumask_bits-1; i >= 0; i--) { 6184 if (!cpumask_test_cpu(i, cpu_map)) 6185 continue; 6186 6187 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { 6188 claim_allocations(i, sd); 6189 init_sched_groups_power(i, sd); 6190 } 6191 } 6192 6193 /* Attach the domains */ 6194 rcu_read_lock(); 6195 for_each_cpu(i, cpu_map) { 6196 sd = *per_cpu_ptr(d.sd, i); 6197 cpu_attach_domain(sd, d.rd, i); 6198 } 6199 rcu_read_unlock(); 6200 6201 ret = 0; 6202error: 6203 __free_domain_allocs(&d, alloc_state, cpu_map); 6204 return ret; 6205} 6206 6207static cpumask_var_t *doms_cur; /* current sched domains */ 6208static int ndoms_cur; /* number of sched domains in 'doms_cur' */ 6209static struct sched_domain_attr *dattr_cur; 6210 /* attribues of custom domains in 'doms_cur' */ 6211 6212/* 6213 * Special case: If a kmalloc of a doms_cur partition (array of 6214 * cpumask) fails, then fallback to a single sched domain, 6215 * as determined by the single cpumask fallback_doms. 6216 */ 6217static cpumask_var_t fallback_doms; 6218 6219/* 6220 * arch_update_cpu_topology lets virtualized architectures update the 6221 * cpu core maps. It is supposed to return 1 if the topology changed 6222 * or 0 if it stayed the same. 6223 */ 6224int __attribute__((weak)) arch_update_cpu_topology(void) 6225{ 6226 return 0; 6227} 6228 6229cpumask_var_t *alloc_sched_domains(unsigned int ndoms) 6230{ 6231 int i; 6232 cpumask_var_t *doms; 6233 6234 doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL); 6235 if (!doms) 6236 return NULL; 6237 for (i = 0; i < ndoms; i++) { 6238 if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) { 6239 free_sched_domains(doms, i); 6240 return NULL; 6241 } 6242 } 6243 return doms; 6244} 6245 6246void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms) 6247{ 6248 unsigned int i; 6249 for (i = 0; i < ndoms; i++) 6250 free_cpumask_var(doms[i]); 6251 kfree(doms); 6252} 6253 6254/* 6255 * Set up scheduler domains and groups. Callers must hold the hotplug lock. 6256 * For now this just excludes isolated cpus, but could be used to 6257 * exclude other special cases in the future. 6258 */ 6259static int init_sched_domains(const struct cpumask *cpu_map) 6260{ 6261 int err; 6262 6263 arch_update_cpu_topology(); 6264 ndoms_cur = 1; 6265 doms_cur = alloc_sched_domains(ndoms_cur); 6266 if (!doms_cur) 6267 doms_cur = &fallback_doms; 6268 cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map); 6269 err = build_sched_domains(doms_cur[0], NULL); 6270 register_sched_domain_sysctl(); 6271 6272 return err; 6273} 6274 6275/* 6276 * Detach sched domains from a group of cpus specified in cpu_map 6277 * These cpus will now be attached to the NULL domain 6278 */ 6279static void detach_destroy_domains(const struct cpumask *cpu_map) 6280{ 6281 int i; 6282 6283 rcu_read_lock(); 6284 for_each_cpu(i, cpu_map) 6285 cpu_attach_domain(NULL, &def_root_domain, i); 6286 rcu_read_unlock(); 6287} 6288 6289/* handle null as "default" */ 6290static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur, 6291 struct sched_domain_attr *new, int idx_new) 6292{ 6293 struct sched_domain_attr tmp; 6294 6295 /* fast path */ 6296 if (!new && !cur) 6297 return 1; 6298 6299 tmp = SD_ATTR_INIT; 6300 return !memcmp(cur ? (cur + idx_cur) : &tmp, 6301 new ? (new + idx_new) : &tmp, 6302 sizeof(struct sched_domain_attr)); 6303} 6304 6305/* 6306 * Partition sched domains as specified by the 'ndoms_new' 6307 * cpumasks in the array doms_new[] of cpumasks. This compares 6308 * doms_new[] to the current sched domain partitioning, doms_cur[]. 6309 * It destroys each deleted domain and builds each new domain. 6310 * 6311 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'. 6312 * The masks don't intersect (don't overlap.) We should setup one 6313 * sched domain for each mask. CPUs not in any of the cpumasks will 6314 * not be load balanced. If the same cpumask appears both in the 6315 * current 'doms_cur' domains and in the new 'doms_new', we can leave 6316 * it as it is. 6317 * 6318 * The passed in 'doms_new' should be allocated using 6319 * alloc_sched_domains. This routine takes ownership of it and will 6320 * free_sched_domains it when done with it. If the caller failed the 6321 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1, 6322 * and partition_sched_domains() will fallback to the single partition 6323 * 'fallback_doms', it also forces the domains to be rebuilt. 6324 * 6325 * If doms_new == NULL it will be replaced with cpu_online_mask. 6326 * ndoms_new == 0 is a special case for destroying existing domains, 6327 * and it will not create the default domain. 6328 * 6329 * Call with hotplug lock held 6330 */ 6331void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[], 6332 struct sched_domain_attr *dattr_new) 6333{ 6334 int i, j, n; 6335 int new_topology; 6336 6337 mutex_lock(&sched_domains_mutex); 6338 6339 /* always unregister in case we don't destroy any domains */ 6340 unregister_sched_domain_sysctl(); 6341 6342 /* Let architecture update cpu core mappings. */ 6343 new_topology = arch_update_cpu_topology(); 6344 6345 n = doms_new ? ndoms_new : 0; 6346 6347 /* Destroy deleted domains */ 6348 for (i = 0; i < ndoms_cur; i++) { 6349 for (j = 0; j < n && !new_topology; j++) { 6350 if (cpumask_equal(doms_cur[i], doms_new[j]) 6351 && dattrs_equal(dattr_cur, i, dattr_new, j)) 6352 goto match1; 6353 } 6354 /* no match - a current sched domain not in new doms_new[] */ 6355 detach_destroy_domains(doms_cur[i]); 6356match1: 6357 ; 6358 } 6359 6360 n = ndoms_cur; 6361 if (doms_new == NULL) { 6362 n = 0; 6363 doms_new = &fallback_doms; 6364 cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map); 6365 WARN_ON_ONCE(dattr_new); 6366 } 6367 6368 /* Build new domains */ 6369 for (i = 0; i < ndoms_new; i++) { 6370 for (j = 0; j < n && !new_topology; j++) { 6371 if (cpumask_equal(doms_new[i], doms_cur[j]) 6372 && dattrs_equal(dattr_new, i, dattr_cur, j)) 6373 goto match2; 6374 } 6375 /* no match - add a new doms_new */ 6376 build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL); 6377match2: 6378 ; 6379 } 6380 6381 /* Remember the new sched domains */ 6382 if (doms_cur != &fallback_doms) 6383 free_sched_domains(doms_cur, ndoms_cur); 6384 kfree(dattr_cur); /* kfree(NULL) is safe */ 6385 doms_cur = doms_new; 6386 dattr_cur = dattr_new; 6387 ndoms_cur = ndoms_new; 6388 6389 register_sched_domain_sysctl(); 6390 6391 mutex_unlock(&sched_domains_mutex); 6392} 6393 6394static int num_cpus_frozen; /* used to mark begin/end of suspend/resume */ 6395 6396/* 6397 * Update cpusets according to cpu_active mask. If cpusets are 6398 * disabled, cpuset_update_active_cpus() becomes a simple wrapper 6399 * around partition_sched_domains(). 6400 * 6401 * If we come here as part of a suspend/resume, don't touch cpusets because we 6402 * want to restore it back to its original state upon resume anyway. 6403 */ 6404static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action, 6405 void *hcpu) 6406{ 6407 switch (action) { 6408 case CPU_ONLINE_FROZEN: 6409 case CPU_DOWN_FAILED_FROZEN: 6410 6411 /* 6412 * num_cpus_frozen tracks how many CPUs are involved in suspend 6413 * resume sequence. As long as this is not the last online 6414 * operation in the resume sequence, just build a single sched 6415 * domain, ignoring cpusets. 6416 */ 6417 num_cpus_frozen--; 6418 if (likely(num_cpus_frozen)) { 6419 partition_sched_domains(1, NULL, NULL); 6420 break; 6421 } 6422 6423 /* 6424 * This is the last CPU online operation. So fall through and 6425 * restore the original sched domains by considering the 6426 * cpuset configurations. 6427 */ 6428 6429 case CPU_ONLINE: 6430 case CPU_DOWN_FAILED: 6431 cpuset_update_active_cpus(true); 6432 break; 6433 default: 6434 return NOTIFY_DONE; 6435 } 6436 return NOTIFY_OK; 6437} 6438 6439static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action, 6440 void *hcpu) 6441{ 6442 switch (action) { 6443 case CPU_DOWN_PREPARE: 6444 cpuset_update_active_cpus(false); 6445 break; 6446 case CPU_DOWN_PREPARE_FROZEN: 6447 num_cpus_frozen++; 6448 partition_sched_domains(1, NULL, NULL); 6449 break; 6450 default: 6451 return NOTIFY_DONE; 6452 } 6453 return NOTIFY_OK; 6454} 6455 6456void __init sched_init_smp(void) 6457{ 6458 cpumask_var_t non_isolated_cpus; 6459 6460 alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL); 6461 alloc_cpumask_var(&fallback_doms, GFP_KERNEL); 6462 6463 sched_init_numa(); 6464 6465 /* 6466 * There's no userspace yet to cause hotplug operations; hence all the 6467 * cpu masks are stable and all blatant races in the below code cannot 6468 * happen. 6469 */ 6470 mutex_lock(&sched_domains_mutex); 6471 init_sched_domains(cpu_active_mask); 6472 cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map); 6473 if (cpumask_empty(non_isolated_cpus)) 6474 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus); 6475 mutex_unlock(&sched_domains_mutex); 6476 6477 hotcpu_notifier(sched_domains_numa_masks_update, CPU_PRI_SCHED_ACTIVE); 6478 hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE); 6479 hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE); 6480 6481 init_hrtick(); 6482 6483 /* Move init over to a non-isolated CPU */ 6484 if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0) 6485 BUG(); 6486 sched_init_granularity(); 6487 free_cpumask_var(non_isolated_cpus); 6488 6489 init_sched_rt_class(); 6490 init_sched_dl_class(); 6491} 6492#else 6493void __init sched_init_smp(void) 6494{ 6495 sched_init_granularity(); 6496} 6497#endif /* CONFIG_SMP */ 6498 6499const_debug unsigned int sysctl_timer_migration = 1; 6500 6501int in_sched_functions(unsigned long addr) 6502{ 6503 return in_lock_functions(addr) || 6504 (addr >= (unsigned long)__sched_text_start 6505 && addr < (unsigned long)__sched_text_end); 6506} 6507 6508#ifdef CONFIG_CGROUP_SCHED 6509/* 6510 * Default task group. 6511 * Every task in system belongs to this group at bootup. 6512 */ 6513struct task_group root_task_group; 6514LIST_HEAD(task_groups); 6515#endif 6516 6517DECLARE_PER_CPU(cpumask_var_t, load_balance_mask); 6518 6519void __init sched_init(void) 6520{ 6521 int i, j; 6522 unsigned long alloc_size = 0, ptr; 6523 6524#ifdef CONFIG_FAIR_GROUP_SCHED 6525 alloc_size += 2 * nr_cpu_ids * sizeof(void **); 6526#endif 6527#ifdef CONFIG_RT_GROUP_SCHED 6528 alloc_size += 2 * nr_cpu_ids * sizeof(void **); 6529#endif 6530#ifdef CONFIG_CPUMASK_OFFSTACK 6531 alloc_size += num_possible_cpus() * cpumask_size(); 6532#endif 6533 if (alloc_size) { 6534 ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT); 6535 6536#ifdef CONFIG_FAIR_GROUP_SCHED 6537 root_task_group.se = (struct sched_entity **)ptr; 6538 ptr += nr_cpu_ids * sizeof(void **); 6539 6540 root_task_group.cfs_rq = (struct cfs_rq **)ptr; 6541 ptr += nr_cpu_ids * sizeof(void **); 6542 6543#endif /* CONFIG_FAIR_GROUP_SCHED */ 6544#ifdef CONFIG_RT_GROUP_SCHED 6545 root_task_group.rt_se = (struct sched_rt_entity **)ptr; 6546 ptr += nr_cpu_ids * sizeof(void **); 6547 6548 root_task_group.rt_rq = (struct rt_rq **)ptr; 6549 ptr += nr_cpu_ids * sizeof(void **); 6550 6551#endif /* CONFIG_RT_GROUP_SCHED */ 6552#ifdef CONFIG_CPUMASK_OFFSTACK 6553 for_each_possible_cpu(i) { 6554 per_cpu(load_balance_mask, i) = (void *)ptr; 6555 ptr += cpumask_size(); 6556 } 6557#endif /* CONFIG_CPUMASK_OFFSTACK */ 6558 } 6559 6560#ifdef CONFIG_SMP 6561 init_defrootdomain(); 6562#endif 6563 6564 init_rt_bandwidth(&def_rt_bandwidth, 6565 global_rt_period(), global_rt_runtime()); 6566 6567#ifdef CONFIG_RT_GROUP_SCHED 6568 init_rt_bandwidth(&root_task_group.rt_bandwidth, 6569 global_rt_period(), global_rt_runtime()); 6570#endif /* CONFIG_RT_GROUP_SCHED */ 6571 6572#ifdef CONFIG_CGROUP_SCHED 6573 list_add(&root_task_group.list, &task_groups); 6574 INIT_LIST_HEAD(&root_task_group.children); 6575 INIT_LIST_HEAD(&root_task_group.siblings); 6576 autogroup_init(&init_task); 6577 6578#endif /* CONFIG_CGROUP_SCHED */ 6579 6580 for_each_possible_cpu(i) { 6581 struct rq *rq; 6582 6583 rq = cpu_rq(i); 6584 raw_spin_lock_init(&rq->lock); 6585 rq->nr_running = 0; 6586 rq->calc_load_active = 0; 6587 rq->calc_load_update = jiffies + LOAD_FREQ; 6588 init_cfs_rq(&rq->cfs); 6589 init_rt_rq(&rq->rt, rq); 6590 init_dl_rq(&rq->dl, rq); 6591#ifdef CONFIG_FAIR_GROUP_SCHED 6592 root_task_group.shares = ROOT_TASK_GROUP_LOAD; 6593 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list); 6594 /* 6595 * How much cpu bandwidth does root_task_group get? 6596 * 6597 * In case of task-groups formed thr' the cgroup filesystem, it 6598 * gets 100% of the cpu resources in the system. This overall 6599 * system cpu resource is divided among the tasks of 6600 * root_task_group and its child task-groups in a fair manner, 6601 * based on each entity's (task or task-group's) weight 6602 * (se->load.weight). 6603 * 6604 * In other words, if root_task_group has 10 tasks of weight 6605 * 1024) and two child groups A0 and A1 (of weight 1024 each), 6606 * then A0's share of the cpu resource is: 6607 * 6608 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33% 6609 * 6610 * We achieve this by letting root_task_group's tasks sit 6611 * directly in rq->cfs (i.e root_task_group->se[] = NULL). 6612 */ 6613 init_cfs_bandwidth(&root_task_group.cfs_bandwidth); 6614 init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL); 6615#endif /* CONFIG_FAIR_GROUP_SCHED */ 6616 6617 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime; 6618#ifdef CONFIG_RT_GROUP_SCHED 6619 INIT_LIST_HEAD(&rq->leaf_rt_rq_list); 6620 init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL); 6621#endif 6622 6623 for (j = 0; j < CPU_LOAD_IDX_MAX; j++) 6624 rq->cpu_load[j] = 0; 6625 6626 rq->last_load_update_tick = jiffies; 6627 6628#ifdef CONFIG_SMP 6629 rq->sd = NULL; 6630 rq->rd = NULL; 6631 rq->cpu_power = SCHED_POWER_SCALE; 6632 rq->post_schedule = 0; 6633 rq->active_balance = 0; 6634 rq->next_balance = jiffies; 6635 rq->push_cpu = 0; 6636 rq->cpu = i; 6637 rq->online = 0; 6638 rq->idle_stamp = 0; 6639 rq->avg_idle = 2*sysctl_sched_migration_cost; 6640 rq->max_idle_balance_cost = sysctl_sched_migration_cost; 6641 6642 INIT_LIST_HEAD(&rq->cfs_tasks); 6643 6644 rq_attach_root(rq, &def_root_domain); 6645#ifdef CONFIG_NO_HZ_COMMON 6646 rq->nohz_flags = 0; 6647#endif 6648#ifdef CONFIG_NO_HZ_FULL 6649 rq->last_sched_tick = 0; 6650#endif 6651#endif 6652 init_rq_hrtick(rq); 6653 atomic_set(&rq->nr_iowait, 0); 6654 } 6655 6656 set_load_weight(&init_task); 6657 6658#ifdef CONFIG_PREEMPT_NOTIFIERS 6659 INIT_HLIST_HEAD(&init_task.preempt_notifiers); 6660#endif 6661 6662 /* 6663 * The boot idle thread does lazy MMU switching as well: 6664 */ 6665 atomic_inc(&init_mm.mm_count); 6666 enter_lazy_tlb(&init_mm, current); 6667 6668 /* 6669 * Make us the idle thread. Technically, schedule() should not be 6670 * called from this thread, however somewhere below it might be, 6671 * but because we are the idle thread, we just pick up running again 6672 * when this runqueue becomes "idle". 6673 */ 6674 init_idle(current, smp_processor_id()); 6675 6676 calc_load_update = jiffies + LOAD_FREQ; 6677 6678 /* 6679 * During early bootup we pretend to be a normal task: 6680 */ 6681 current->sched_class = &fair_sched_class; 6682 6683#ifdef CONFIG_SMP 6684 zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT); 6685 /* May be allocated at isolcpus cmdline parse time */ 6686 if (cpu_isolated_map == NULL) 6687 zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT); 6688 idle_thread_set_boot_cpu(); 6689#endif 6690 init_sched_fair_class(); 6691 6692 scheduler_running = 1; 6693} 6694 6695#ifdef CONFIG_DEBUG_ATOMIC_SLEEP 6696static inline int preempt_count_equals(int preempt_offset) 6697{ 6698 int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth(); 6699 6700 return (nested == preempt_offset); 6701} 6702 6703void __might_sleep(const char *file, int line, int preempt_offset) 6704{ 6705 static unsigned long prev_jiffy; /* ratelimiting */ 6706 6707 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */ 6708 if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) || 6709 system_state != SYSTEM_RUNNING || oops_in_progress) 6710 return; 6711 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) 6712 return; 6713 prev_jiffy = jiffies; 6714 6715 printk(KERN_ERR 6716 "BUG: sleeping function called from invalid context at %s:%d\n", 6717 file, line); 6718 printk(KERN_ERR 6719 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n", 6720 in_atomic(), irqs_disabled(), 6721 current->pid, current->comm); 6722 6723 debug_show_held_locks(current); 6724 if (irqs_disabled()) 6725 print_irqtrace_events(current); 6726 dump_stack(); 6727} 6728EXPORT_SYMBOL(__might_sleep); 6729#endif 6730 6731#ifdef CONFIG_MAGIC_SYSRQ 6732static void normalize_task(struct rq *rq, struct task_struct *p) 6733{ 6734 const struct sched_class *prev_class = p->sched_class; 6735 struct sched_attr attr = { 6736 .sched_policy = SCHED_NORMAL, 6737 }; 6738 int old_prio = p->prio; 6739 int on_rq; 6740 6741 on_rq = p->on_rq; 6742 if (on_rq) 6743 dequeue_task(rq, p, 0); 6744 __setscheduler(rq, p, &attr); 6745 if (on_rq) { 6746 enqueue_task(rq, p, 0); 6747 resched_task(rq->curr); 6748 } 6749 6750 check_class_changed(rq, p, prev_class, old_prio); 6751} 6752 6753void normalize_rt_tasks(void) 6754{ 6755 struct task_struct *g, *p; 6756 unsigned long flags; 6757 struct rq *rq; 6758 6759 read_lock_irqsave(&tasklist_lock, flags); 6760 do_each_thread(g, p) { 6761 /* 6762 * Only normalize user tasks: 6763 */ 6764 if (!p->mm) 6765 continue; 6766 6767 p->se.exec_start = 0; 6768#ifdef CONFIG_SCHEDSTATS 6769 p->se.statistics.wait_start = 0; 6770 p->se.statistics.sleep_start = 0; 6771 p->se.statistics.block_start = 0; 6772#endif 6773 6774 if (!dl_task(p) && !rt_task(p)) { 6775 /* 6776 * Renice negative nice level userspace 6777 * tasks back to 0: 6778 */ 6779 if (TASK_NICE(p) < 0 && p->mm) 6780 set_user_nice(p, 0); 6781 continue; 6782 } 6783 6784 raw_spin_lock(&p->pi_lock); 6785 rq = __task_rq_lock(p); 6786 6787 normalize_task(rq, p); 6788 6789 __task_rq_unlock(rq); 6790 raw_spin_unlock(&p->pi_lock); 6791 } while_each_thread(g, p); 6792 6793 read_unlock_irqrestore(&tasklist_lock, flags); 6794} 6795 6796#endif /* CONFIG_MAGIC_SYSRQ */ 6797 6798#if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) 6799/* 6800 * These functions are only useful for the IA64 MCA handling, or kdb. 6801 * 6802 * They can only be called when the whole system has been 6803 * stopped - every CPU needs to be quiescent, and no scheduling 6804 * activity can take place. Using them for anything else would 6805 * be a serious bug, and as a result, they aren't even visible 6806 * under any other configuration. 6807 */ 6808 6809/** 6810 * curr_task - return the current task for a given cpu. 6811 * @cpu: the processor in question. 6812 * 6813 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! 6814 * 6815 * Return: The current task for @cpu. 6816 */ 6817struct task_struct *curr_task(int cpu) 6818{ 6819 return cpu_curr(cpu); 6820} 6821 6822#endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */ 6823 6824#ifdef CONFIG_IA64 6825/** 6826 * set_curr_task - set the current task for a given cpu. 6827 * @cpu: the processor in question. 6828 * @p: the task pointer to set. 6829 * 6830 * Description: This function must only be used when non-maskable interrupts 6831 * are serviced on a separate stack. It allows the architecture to switch the 6832 * notion of the current task on a cpu in a non-blocking manner. This function 6833 * must be called with all CPU's synchronized, and interrupts disabled, the 6834 * and caller must save the original value of the current task (see 6835 * curr_task() above) and restore that value before reenabling interrupts and 6836 * re-starting the system. 6837 * 6838 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! 6839 */ 6840void set_curr_task(int cpu, struct task_struct *p) 6841{ 6842 cpu_curr(cpu) = p; 6843} 6844 6845#endif 6846 6847#ifdef CONFIG_CGROUP_SCHED 6848/* task_group_lock serializes the addition/removal of task groups */ 6849static DEFINE_SPINLOCK(task_group_lock); 6850 6851static void free_sched_group(struct task_group *tg) 6852{ 6853 free_fair_sched_group(tg); 6854 free_rt_sched_group(tg); 6855 autogroup_free(tg); 6856 kfree(tg); 6857} 6858 6859/* allocate runqueue etc for a new task group */ 6860struct task_group *sched_create_group(struct task_group *parent) 6861{ 6862 struct task_group *tg; 6863 6864 tg = kzalloc(sizeof(*tg), GFP_KERNEL); 6865 if (!tg) 6866 return ERR_PTR(-ENOMEM); 6867 6868 if (!alloc_fair_sched_group(tg, parent)) 6869 goto err; 6870 6871 if (!alloc_rt_sched_group(tg, parent)) 6872 goto err; 6873 6874 return tg; 6875 6876err: 6877 free_sched_group(tg); 6878 return ERR_PTR(-ENOMEM); 6879} 6880 6881void sched_online_group(struct task_group *tg, struct task_group *parent) 6882{ 6883 unsigned long flags; 6884 6885 spin_lock_irqsave(&task_group_lock, flags); 6886 list_add_rcu(&tg->list, &task_groups); 6887 6888 WARN_ON(!parent); /* root should already exist */ 6889 6890 tg->parent = parent; 6891 INIT_LIST_HEAD(&tg->children); 6892 list_add_rcu(&tg->siblings, &parent->children); 6893 spin_unlock_irqrestore(&task_group_lock, flags); 6894} 6895 6896/* rcu callback to free various structures associated with a task group */ 6897static void free_sched_group_rcu(struct rcu_head *rhp) 6898{ 6899 /* now it should be safe to free those cfs_rqs */ 6900 free_sched_group(container_of(rhp, struct task_group, rcu)); 6901} 6902 6903/* Destroy runqueue etc associated with a task group */ 6904void sched_destroy_group(struct task_group *tg) 6905{ 6906 /* wait for possible concurrent references to cfs_rqs complete */ 6907 call_rcu(&tg->rcu, free_sched_group_rcu); 6908} 6909 6910void sched_offline_group(struct task_group *tg) 6911{ 6912 unsigned long flags; 6913 int i; 6914 6915 /* end participation in shares distribution */ 6916 for_each_possible_cpu(i) 6917 unregister_fair_sched_group(tg, i); 6918 6919 spin_lock_irqsave(&task_group_lock, flags); 6920 list_del_rcu(&tg->list); 6921 list_del_rcu(&tg->siblings); 6922 spin_unlock_irqrestore(&task_group_lock, flags); 6923} 6924 6925/* change task's runqueue when it moves between groups. 6926 * The caller of this function should have put the task in its new group 6927 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to 6928 * reflect its new group. 6929 */ 6930void sched_move_task(struct task_struct *tsk) 6931{ 6932 struct task_group *tg; 6933 int on_rq, running; 6934 unsigned long flags; 6935 struct rq *rq; 6936 6937 rq = task_rq_lock(tsk, &flags); 6938 6939 running = task_current(rq, tsk); 6940 on_rq = tsk->on_rq; 6941 6942 if (on_rq) 6943 dequeue_task(rq, tsk, 0); 6944 if (unlikely(running)) 6945 tsk->sched_class->put_prev_task(rq, tsk); 6946 6947 tg = container_of(task_css_check(tsk, cpu_cgroup_subsys_id, 6948 lockdep_is_held(&tsk->sighand->siglock)), 6949 struct task_group, css); 6950 tg = autogroup_task_group(tsk, tg); 6951 tsk->sched_task_group = tg; 6952 6953#ifdef CONFIG_FAIR_GROUP_SCHED 6954 if (tsk->sched_class->task_move_group) 6955 tsk->sched_class->task_move_group(tsk, on_rq); 6956 else 6957#endif 6958 set_task_rq(tsk, task_cpu(tsk)); 6959 6960 if (unlikely(running)) 6961 tsk->sched_class->set_curr_task(rq); 6962 if (on_rq) 6963 enqueue_task(rq, tsk, 0); 6964 6965 task_rq_unlock(rq, tsk, &flags); 6966} 6967#endif /* CONFIG_CGROUP_SCHED */ 6968 6969#if defined(CONFIG_RT_GROUP_SCHED) || defined(CONFIG_CFS_BANDWIDTH) 6970static unsigned long to_ratio(u64 period, u64 runtime) 6971{ 6972 if (runtime == RUNTIME_INF) 6973 return 1ULL << 20; 6974 6975 return div64_u64(runtime << 20, period); 6976} 6977#endif 6978 6979#ifdef CONFIG_RT_GROUP_SCHED 6980/* 6981 * Ensure that the real time constraints are schedulable. 6982 */ 6983static DEFINE_MUTEX(rt_constraints_mutex); 6984 6985/* Must be called with tasklist_lock held */ 6986static inline int tg_has_rt_tasks(struct task_group *tg) 6987{ 6988 struct task_struct *g, *p; 6989 6990 do_each_thread(g, p) { 6991 if (rt_task(p) && task_rq(p)->rt.tg == tg) 6992 return 1; 6993 } while_each_thread(g, p); 6994 6995 return 0; 6996} 6997 6998struct rt_schedulable_data { 6999 struct task_group *tg; 7000 u64 rt_period; 7001 u64 rt_runtime; 7002}; 7003 7004static int tg_rt_schedulable(struct task_group *tg, void *data) 7005{ 7006 struct rt_schedulable_data *d = data; 7007 struct task_group *child; 7008 unsigned long total, sum = 0; 7009 u64 period, runtime; 7010 7011 period = ktime_to_ns(tg->rt_bandwidth.rt_period); 7012 runtime = tg->rt_bandwidth.rt_runtime; 7013 7014 if (tg == d->tg) { 7015 period = d->rt_period; 7016 runtime = d->rt_runtime; 7017 } 7018 7019 /* 7020 * Cannot have more runtime than the period. 7021 */ 7022 if (runtime > period && runtime != RUNTIME_INF) 7023 return -EINVAL; 7024 7025 /* 7026 * Ensure we don't starve existing RT tasks. 7027 */ 7028 if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg)) 7029 return -EBUSY; 7030 7031 total = to_ratio(period, runtime); 7032 7033 /* 7034 * Nobody can have more than the global setting allows. 7035 */ 7036 if (total > to_ratio(global_rt_period(), global_rt_runtime())) 7037 return -EINVAL; 7038 7039 /* 7040 * The sum of our children's runtime should not exceed our own. 7041 */ 7042 list_for_each_entry_rcu(child, &tg->children, siblings) { 7043 period = ktime_to_ns(child->rt_bandwidth.rt_period); 7044 runtime = child->rt_bandwidth.rt_runtime; 7045 7046 if (child == d->tg) { 7047 period = d->rt_period; 7048 runtime = d->rt_runtime; 7049 } 7050 7051 sum += to_ratio(period, runtime); 7052 } 7053 7054 if (sum > total) 7055 return -EINVAL; 7056 7057 return 0; 7058} 7059 7060static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime) 7061{ 7062 int ret; 7063 7064 struct rt_schedulable_data data = { 7065 .tg = tg, 7066 .rt_period = period, 7067 .rt_runtime = runtime, 7068 }; 7069 7070 rcu_read_lock(); 7071 ret = walk_tg_tree(tg_rt_schedulable, tg_nop, &data); 7072 rcu_read_unlock(); 7073 7074 return ret; 7075} 7076 7077static int tg_set_rt_bandwidth(struct task_group *tg, 7078 u64 rt_period, u64 rt_runtime) 7079{ 7080 int i, err = 0; 7081 7082 mutex_lock(&rt_constraints_mutex); 7083 read_lock(&tasklist_lock); 7084 err = __rt_schedulable(tg, rt_period, rt_runtime); 7085 if (err) 7086 goto unlock; 7087 7088 raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock); 7089 tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period); 7090 tg->rt_bandwidth.rt_runtime = rt_runtime; 7091 7092 for_each_possible_cpu(i) { 7093 struct rt_rq *rt_rq = tg->rt_rq[i]; 7094 7095 raw_spin_lock(&rt_rq->rt_runtime_lock); 7096 rt_rq->rt_runtime = rt_runtime; 7097 raw_spin_unlock(&rt_rq->rt_runtime_lock); 7098 } 7099 raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock); 7100unlock: 7101 read_unlock(&tasklist_lock); 7102 mutex_unlock(&rt_constraints_mutex); 7103 7104 return err; 7105} 7106 7107static int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us) 7108{ 7109 u64 rt_runtime, rt_period; 7110 7111 rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period); 7112 rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC; 7113 if (rt_runtime_us < 0) 7114 rt_runtime = RUNTIME_INF; 7115 7116 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); 7117} 7118 7119static long sched_group_rt_runtime(struct task_group *tg) 7120{ 7121 u64 rt_runtime_us; 7122 7123 if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF) 7124 return -1; 7125 7126 rt_runtime_us = tg->rt_bandwidth.rt_runtime; 7127 do_div(rt_runtime_us, NSEC_PER_USEC); 7128 return rt_runtime_us; 7129} 7130 7131static int sched_group_set_rt_period(struct task_group *tg, long rt_period_us) 7132{ 7133 u64 rt_runtime, rt_period; 7134 7135 rt_period = (u64)rt_period_us * NSEC_PER_USEC; 7136 rt_runtime = tg->rt_bandwidth.rt_runtime; 7137 7138 if (rt_period == 0) 7139 return -EINVAL; 7140 7141 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); 7142} 7143 7144static long sched_group_rt_period(struct task_group *tg) 7145{ 7146 u64 rt_period_us; 7147 7148 rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period); 7149 do_div(rt_period_us, NSEC_PER_USEC); 7150 return rt_period_us; 7151} 7152 7153static int sched_rt_global_constraints(void) 7154{ 7155 u64 runtime, period; 7156 int ret = 0; 7157 7158 if (sysctl_sched_rt_period <= 0) 7159 return -EINVAL; 7160 7161 runtime = global_rt_runtime(); 7162 period = global_rt_period(); 7163 7164 /* 7165 * Sanity check on the sysctl variables. 7166 */ 7167 if (runtime > period && runtime != RUNTIME_INF) 7168 return -EINVAL; 7169 7170 mutex_lock(&rt_constraints_mutex); 7171 read_lock(&tasklist_lock); 7172 ret = __rt_schedulable(NULL, 0, 0); 7173 read_unlock(&tasklist_lock); 7174 mutex_unlock(&rt_constraints_mutex); 7175 7176 return ret; 7177} 7178 7179static int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk) 7180{ 7181 /* Don't accept realtime tasks when there is no way for them to run */ 7182 if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0) 7183 return 0; 7184 7185 return 1; 7186} 7187 7188#else /* !CONFIG_RT_GROUP_SCHED */ 7189static int sched_rt_global_constraints(void) 7190{ 7191 unsigned long flags; 7192 int i; 7193 7194 if (sysctl_sched_rt_period <= 0) 7195 return -EINVAL; 7196 7197 /* 7198 * There's always some RT tasks in the root group 7199 * -- migration, kstopmachine etc.. 7200 */ 7201 if (sysctl_sched_rt_runtime == 0) 7202 return -EBUSY; 7203 7204 raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags); 7205 for_each_possible_cpu(i) { 7206 struct rt_rq *rt_rq = &cpu_rq(i)->rt; 7207 7208 raw_spin_lock(&rt_rq->rt_runtime_lock); 7209 rt_rq->rt_runtime = global_rt_runtime(); 7210 raw_spin_unlock(&rt_rq->rt_runtime_lock); 7211 } 7212 raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags); 7213 7214 return 0; 7215} 7216#endif /* CONFIG_RT_GROUP_SCHED */ 7217 7218int sched_rr_handler(struct ctl_table *table, int write, 7219 void __user *buffer, size_t *lenp, 7220 loff_t *ppos) 7221{ 7222 int ret; 7223 static DEFINE_MUTEX(mutex); 7224 7225 mutex_lock(&mutex); 7226 ret = proc_dointvec(table, write, buffer, lenp, ppos); 7227 /* make sure that internally we keep jiffies */ 7228 /* also, writing zero resets timeslice to default */ 7229 if (!ret && write) { 7230 sched_rr_timeslice = sched_rr_timeslice <= 0 ? 7231 RR_TIMESLICE : msecs_to_jiffies(sched_rr_timeslice); 7232 } 7233 mutex_unlock(&mutex); 7234 return ret; 7235} 7236 7237int sched_rt_handler(struct ctl_table *table, int write, 7238 void __user *buffer, size_t *lenp, 7239 loff_t *ppos) 7240{ 7241 int ret; 7242 int old_period, old_runtime; 7243 static DEFINE_MUTEX(mutex); 7244 7245 mutex_lock(&mutex); 7246 old_period = sysctl_sched_rt_period; 7247 old_runtime = sysctl_sched_rt_runtime; 7248 7249 ret = proc_dointvec(table, write, buffer, lenp, ppos); 7250 7251 if (!ret && write) { 7252 ret = sched_rt_global_constraints(); 7253 if (ret) { 7254 sysctl_sched_rt_period = old_period; 7255 sysctl_sched_rt_runtime = old_runtime; 7256 } else { 7257 def_rt_bandwidth.rt_runtime = global_rt_runtime(); 7258 def_rt_bandwidth.rt_period = 7259 ns_to_ktime(global_rt_period()); 7260 } 7261 } 7262 mutex_unlock(&mutex); 7263 7264 return ret; 7265} 7266 7267#ifdef CONFIG_CGROUP_SCHED 7268 7269static inline struct task_group *css_tg(struct cgroup_subsys_state *css) 7270{ 7271 return css ? container_of(css, struct task_group, css) : NULL; 7272} 7273 7274static struct cgroup_subsys_state * 7275cpu_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) 7276{ 7277 struct task_group *parent = css_tg(parent_css); 7278 struct task_group *tg; 7279 7280 if (!parent) { 7281 /* This is early initialization for the top cgroup */ 7282 return &root_task_group.css; 7283 } 7284 7285 tg = sched_create_group(parent); 7286 if (IS_ERR(tg)) 7287 return ERR_PTR(-ENOMEM); 7288 7289 return &tg->css; 7290} 7291 7292static int cpu_cgroup_css_online(struct cgroup_subsys_state *css) 7293{ 7294 struct task_group *tg = css_tg(css); 7295 struct task_group *parent = css_tg(css_parent(css)); 7296 7297 if (parent) 7298 sched_online_group(tg, parent); 7299 return 0; 7300} 7301 7302static void cpu_cgroup_css_free(struct cgroup_subsys_state *css) 7303{ 7304 struct task_group *tg = css_tg(css); 7305 7306 sched_destroy_group(tg); 7307} 7308 7309static void cpu_cgroup_css_offline(struct cgroup_subsys_state *css) 7310{ 7311 struct task_group *tg = css_tg(css); 7312 7313 sched_offline_group(tg); 7314} 7315 7316static int cpu_cgroup_can_attach(struct cgroup_subsys_state *css, 7317 struct cgroup_taskset *tset) 7318{ 7319 struct task_struct *task; 7320 7321 cgroup_taskset_for_each(task, css, tset) { 7322#ifdef CONFIG_RT_GROUP_SCHED 7323 if (!sched_rt_can_attach(css_tg(css), task)) 7324 return -EINVAL; 7325#else 7326 /* We don't support RT-tasks being in separate groups */ 7327 if (task->sched_class != &fair_sched_class) 7328 return -EINVAL; 7329#endif 7330 } 7331 return 0; 7332} 7333 7334static void cpu_cgroup_attach(struct cgroup_subsys_state *css, 7335 struct cgroup_taskset *tset) 7336{ 7337 struct task_struct *task; 7338 7339 cgroup_taskset_for_each(task, css, tset) 7340 sched_move_task(task); 7341} 7342 7343static void cpu_cgroup_exit(struct cgroup_subsys_state *css, 7344 struct cgroup_subsys_state *old_css, 7345 struct task_struct *task) 7346{ 7347 /* 7348 * cgroup_exit() is called in the copy_process() failure path. 7349 * Ignore this case since the task hasn't ran yet, this avoids 7350 * trying to poke a half freed task state from generic code. 7351 */ 7352 if (!(task->flags & PF_EXITING)) 7353 return; 7354 7355 sched_move_task(task); 7356} 7357 7358#ifdef CONFIG_FAIR_GROUP_SCHED 7359static int cpu_shares_write_u64(struct cgroup_subsys_state *css, 7360 struct cftype *cftype, u64 shareval) 7361{ 7362 return sched_group_set_shares(css_tg(css), scale_load(shareval)); 7363} 7364 7365static u64 cpu_shares_read_u64(struct cgroup_subsys_state *css, 7366 struct cftype *cft) 7367{ 7368 struct task_group *tg = css_tg(css); 7369 7370 return (u64) scale_load_down(tg->shares); 7371} 7372 7373#ifdef CONFIG_CFS_BANDWIDTH 7374static DEFINE_MUTEX(cfs_constraints_mutex); 7375 7376const u64 max_cfs_quota_period = 1 * NSEC_PER_SEC; /* 1s */ 7377const u64 min_cfs_quota_period = 1 * NSEC_PER_MSEC; /* 1ms */ 7378 7379static int __cfs_schedulable(struct task_group *tg, u64 period, u64 runtime); 7380 7381static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota) 7382{ 7383 int i, ret = 0, runtime_enabled, runtime_was_enabled; 7384 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 7385 7386 if (tg == &root_task_group) 7387 return -EINVAL; 7388 7389 /* 7390 * Ensure we have at some amount of bandwidth every period. This is 7391 * to prevent reaching a state of large arrears when throttled via 7392 * entity_tick() resulting in prolonged exit starvation. 7393 */ 7394 if (quota < min_cfs_quota_period || period < min_cfs_quota_period) 7395 return -EINVAL; 7396 7397 /* 7398 * Likewise, bound things on the otherside by preventing insane quota 7399 * periods. This also allows us to normalize in computing quota 7400 * feasibility. 7401 */ 7402 if (period > max_cfs_quota_period) 7403 return -EINVAL; 7404 7405 mutex_lock(&cfs_constraints_mutex); 7406 ret = __cfs_schedulable(tg, period, quota); 7407 if (ret) 7408 goto out_unlock; 7409 7410 runtime_enabled = quota != RUNTIME_INF; 7411 runtime_was_enabled = cfs_b->quota != RUNTIME_INF; 7412 /* 7413 * If we need to toggle cfs_bandwidth_used, off->on must occur 7414 * before making related changes, and on->off must occur afterwards 7415 */ 7416 if (runtime_enabled && !runtime_was_enabled) 7417 cfs_bandwidth_usage_inc(); 7418 raw_spin_lock_irq(&cfs_b->lock); 7419 cfs_b->period = ns_to_ktime(period); 7420 cfs_b->quota = quota; 7421 7422 __refill_cfs_bandwidth_runtime(cfs_b); 7423 /* restart the period timer (if active) to handle new period expiry */ 7424 if (runtime_enabled && cfs_b->timer_active) { 7425 /* force a reprogram */ 7426 cfs_b->timer_active = 0; 7427 __start_cfs_bandwidth(cfs_b); 7428 } 7429 raw_spin_unlock_irq(&cfs_b->lock); 7430 7431 for_each_possible_cpu(i) { 7432 struct cfs_rq *cfs_rq = tg->cfs_rq[i]; 7433 struct rq *rq = cfs_rq->rq; 7434 7435 raw_spin_lock_irq(&rq->lock); 7436 cfs_rq->runtime_enabled = runtime_enabled; 7437 cfs_rq->runtime_remaining = 0; 7438 7439 if (cfs_rq->throttled) 7440 unthrottle_cfs_rq(cfs_rq); 7441 raw_spin_unlock_irq(&rq->lock); 7442 } 7443 if (runtime_was_enabled && !runtime_enabled) 7444 cfs_bandwidth_usage_dec(); 7445out_unlock: 7446 mutex_unlock(&cfs_constraints_mutex); 7447 7448 return ret; 7449} 7450 7451int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us) 7452{ 7453 u64 quota, period; 7454 7455 period = ktime_to_ns(tg->cfs_bandwidth.period); 7456 if (cfs_quota_us < 0) 7457 quota = RUNTIME_INF; 7458 else 7459 quota = (u64)cfs_quota_us * NSEC_PER_USEC; 7460 7461 return tg_set_cfs_bandwidth(tg, period, quota); 7462} 7463 7464long tg_get_cfs_quota(struct task_group *tg) 7465{ 7466 u64 quota_us; 7467 7468 if (tg->cfs_bandwidth.quota == RUNTIME_INF) 7469 return -1; 7470 7471 quota_us = tg->cfs_bandwidth.quota; 7472 do_div(quota_us, NSEC_PER_USEC); 7473 7474 return quota_us; 7475} 7476 7477int tg_set_cfs_period(struct task_group *tg, long cfs_period_us) 7478{ 7479 u64 quota, period; 7480 7481 period = (u64)cfs_period_us * NSEC_PER_USEC; 7482 quota = tg->cfs_bandwidth.quota; 7483 7484 return tg_set_cfs_bandwidth(tg, period, quota); 7485} 7486 7487long tg_get_cfs_period(struct task_group *tg) 7488{ 7489 u64 cfs_period_us; 7490 7491 cfs_period_us = ktime_to_ns(tg->cfs_bandwidth.period); 7492 do_div(cfs_period_us, NSEC_PER_USEC); 7493 7494 return cfs_period_us; 7495} 7496 7497static s64 cpu_cfs_quota_read_s64(struct cgroup_subsys_state *css, 7498 struct cftype *cft) 7499{ 7500 return tg_get_cfs_quota(css_tg(css)); 7501} 7502 7503static int cpu_cfs_quota_write_s64(struct cgroup_subsys_state *css, 7504 struct cftype *cftype, s64 cfs_quota_us) 7505{ 7506 return tg_set_cfs_quota(css_tg(css), cfs_quota_us); 7507} 7508 7509static u64 cpu_cfs_period_read_u64(struct cgroup_subsys_state *css, 7510 struct cftype *cft) 7511{ 7512 return tg_get_cfs_period(css_tg(css)); 7513} 7514 7515static int cpu_cfs_period_write_u64(struct cgroup_subsys_state *css, 7516 struct cftype *cftype, u64 cfs_period_us) 7517{ 7518 return tg_set_cfs_period(css_tg(css), cfs_period_us); 7519} 7520 7521struct cfs_schedulable_data { 7522 struct task_group *tg; 7523 u64 period, quota; 7524}; 7525 7526/* 7527 * normalize group quota/period to be quota/max_period 7528 * note: units are usecs 7529 */ 7530static u64 normalize_cfs_quota(struct task_group *tg, 7531 struct cfs_schedulable_data *d) 7532{ 7533 u64 quota, period; 7534 7535 if (tg == d->tg) { 7536 period = d->period; 7537 quota = d->quota; 7538 } else { 7539 period = tg_get_cfs_period(tg); 7540 quota = tg_get_cfs_quota(tg); 7541 } 7542 7543 /* note: these should typically be equivalent */ 7544 if (quota == RUNTIME_INF || quota == -1) 7545 return RUNTIME_INF; 7546 7547 return to_ratio(period, quota); 7548} 7549 7550static int tg_cfs_schedulable_down(struct task_group *tg, void *data) 7551{ 7552 struct cfs_schedulable_data *d = data; 7553 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 7554 s64 quota = 0, parent_quota = -1; 7555 7556 if (!tg->parent) { 7557 quota = RUNTIME_INF; 7558 } else { 7559 struct cfs_bandwidth *parent_b = &tg->parent->cfs_bandwidth; 7560 7561 quota = normalize_cfs_quota(tg, d); 7562 parent_quota = parent_b->hierarchal_quota; 7563 7564 /* 7565 * ensure max(child_quota) <= parent_quota, inherit when no 7566 * limit is set 7567 */ 7568 if (quota == RUNTIME_INF) 7569 quota = parent_quota; 7570 else if (parent_quota != RUNTIME_INF && quota > parent_quota) 7571 return -EINVAL; 7572 } 7573 cfs_b->hierarchal_quota = quota; 7574 7575 return 0; 7576} 7577 7578static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota) 7579{ 7580 int ret; 7581 struct cfs_schedulable_data data = { 7582 .tg = tg, 7583 .period = period, 7584 .quota = quota, 7585 }; 7586 7587 if (quota != RUNTIME_INF) { 7588 do_div(data.period, NSEC_PER_USEC); 7589 do_div(data.quota, NSEC_PER_USEC); 7590 } 7591 7592 rcu_read_lock(); 7593 ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data); 7594 rcu_read_unlock(); 7595 7596 return ret; 7597} 7598 7599static int cpu_stats_show(struct cgroup_subsys_state *css, struct cftype *cft, 7600 struct cgroup_map_cb *cb) 7601{ 7602 struct task_group *tg = css_tg(css); 7603 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 7604 7605 cb->fill(cb, "nr_periods", cfs_b->nr_periods); 7606 cb->fill(cb, "nr_throttled", cfs_b->nr_throttled); 7607 cb->fill(cb, "throttled_time", cfs_b->throttled_time); 7608 7609 return 0; 7610} 7611#endif /* CONFIG_CFS_BANDWIDTH */ 7612#endif /* CONFIG_FAIR_GROUP_SCHED */ 7613 7614#ifdef CONFIG_RT_GROUP_SCHED 7615static int cpu_rt_runtime_write(struct cgroup_subsys_state *css, 7616 struct cftype *cft, s64 val) 7617{ 7618 return sched_group_set_rt_runtime(css_tg(css), val); 7619} 7620 7621static s64 cpu_rt_runtime_read(struct cgroup_subsys_state *css, 7622 struct cftype *cft) 7623{ 7624 return sched_group_rt_runtime(css_tg(css)); 7625} 7626 7627static int cpu_rt_period_write_uint(struct cgroup_subsys_state *css, 7628 struct cftype *cftype, u64 rt_period_us) 7629{ 7630 return sched_group_set_rt_period(css_tg(css), rt_period_us); 7631} 7632 7633static u64 cpu_rt_period_read_uint(struct cgroup_subsys_state *css, 7634 struct cftype *cft) 7635{ 7636 return sched_group_rt_period(css_tg(css)); 7637} 7638#endif /* CONFIG_RT_GROUP_SCHED */ 7639 7640static struct cftype cpu_files[] = { 7641#ifdef CONFIG_FAIR_GROUP_SCHED 7642 { 7643 .name = "shares", 7644 .read_u64 = cpu_shares_read_u64, 7645 .write_u64 = cpu_shares_write_u64, 7646 }, 7647#endif 7648#ifdef CONFIG_CFS_BANDWIDTH 7649 { 7650 .name = "cfs_quota_us", 7651 .read_s64 = cpu_cfs_quota_read_s64, 7652 .write_s64 = cpu_cfs_quota_write_s64, 7653 }, 7654 { 7655 .name = "cfs_period_us", 7656 .read_u64 = cpu_cfs_period_read_u64, 7657 .write_u64 = cpu_cfs_period_write_u64, 7658 }, 7659 { 7660 .name = "stat", 7661 .read_map = cpu_stats_show, 7662 }, 7663#endif 7664#ifdef CONFIG_RT_GROUP_SCHED 7665 { 7666 .name = "rt_runtime_us", 7667 .read_s64 = cpu_rt_runtime_read, 7668 .write_s64 = cpu_rt_runtime_write, 7669 }, 7670 { 7671 .name = "rt_period_us", 7672 .read_u64 = cpu_rt_period_read_uint, 7673 .write_u64 = cpu_rt_period_write_uint, 7674 }, 7675#endif 7676 { } /* terminate */ 7677}; 7678 7679struct cgroup_subsys cpu_cgroup_subsys = { 7680 .name = "cpu", 7681 .css_alloc = cpu_cgroup_css_alloc, 7682 .css_free = cpu_cgroup_css_free, 7683 .css_online = cpu_cgroup_css_online, 7684 .css_offline = cpu_cgroup_css_offline, 7685 .can_attach = cpu_cgroup_can_attach, 7686 .attach = cpu_cgroup_attach, 7687 .exit = cpu_cgroup_exit, 7688 .subsys_id = cpu_cgroup_subsys_id, 7689 .base_cftypes = cpu_files, 7690 .early_init = 1, 7691}; 7692 7693#endif /* CONFIG_CGROUP_SCHED */ 7694 7695void dump_cpu_task(int cpu) 7696{ 7697 pr_info("Task dump for CPU %d:\n", cpu); 7698 sched_show_task(cpu_curr(cpu)); 7699} 7700