core.c revision b8593bfda1652755136333cdd362de125b283a9c
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 76#include <asm/switch_to.h> 77#include <asm/tlb.h> 78#include <asm/irq_regs.h> 79#include <asm/mutex.h> 80#ifdef CONFIG_PARAVIRT 81#include <asm/paravirt.h> 82#endif 83 84#include "sched.h" 85#include "../workqueue_sched.h" 86#include "../smpboot.h" 87 88#define CREATE_TRACE_POINTS 89#include <trace/events/sched.h> 90 91void start_bandwidth_timer(struct hrtimer *period_timer, ktime_t period) 92{ 93 unsigned long delta; 94 ktime_t soft, hard, now; 95 96 for (;;) { 97 if (hrtimer_active(period_timer)) 98 break; 99 100 now = hrtimer_cb_get_time(period_timer); 101 hrtimer_forward(period_timer, now, period); 102 103 soft = hrtimer_get_softexpires(period_timer); 104 hard = hrtimer_get_expires(period_timer); 105 delta = ktime_to_ns(ktime_sub(hard, soft)); 106 __hrtimer_start_range_ns(period_timer, soft, delta, 107 HRTIMER_MODE_ABS_PINNED, 0); 108 } 109} 110 111DEFINE_MUTEX(sched_domains_mutex); 112DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); 113 114static void update_rq_clock_task(struct rq *rq, s64 delta); 115 116void update_rq_clock(struct rq *rq) 117{ 118 s64 delta; 119 120 if (rq->skip_clock_update > 0) 121 return; 122 123 delta = sched_clock_cpu(cpu_of(rq)) - rq->clock; 124 rq->clock += delta; 125 update_rq_clock_task(rq, delta); 126} 127 128/* 129 * Debugging: various feature bits 130 */ 131 132#define SCHED_FEAT(name, enabled) \ 133 (1UL << __SCHED_FEAT_##name) * enabled | 134 135const_debug unsigned int sysctl_sched_features = 136#include "features.h" 137 0; 138 139#undef SCHED_FEAT 140 141#ifdef CONFIG_SCHED_DEBUG 142#define SCHED_FEAT(name, enabled) \ 143 #name , 144 145static const char * const sched_feat_names[] = { 146#include "features.h" 147}; 148 149#undef SCHED_FEAT 150 151static int sched_feat_show(struct seq_file *m, void *v) 152{ 153 int i; 154 155 for (i = 0; i < __SCHED_FEAT_NR; i++) { 156 if (!(sysctl_sched_features & (1UL << i))) 157 seq_puts(m, "NO_"); 158 seq_printf(m, "%s ", sched_feat_names[i]); 159 } 160 seq_puts(m, "\n"); 161 162 return 0; 163} 164 165#ifdef HAVE_JUMP_LABEL 166 167#define jump_label_key__true STATIC_KEY_INIT_TRUE 168#define jump_label_key__false STATIC_KEY_INIT_FALSE 169 170#define SCHED_FEAT(name, enabled) \ 171 jump_label_key__##enabled , 172 173struct static_key sched_feat_keys[__SCHED_FEAT_NR] = { 174#include "features.h" 175}; 176 177#undef SCHED_FEAT 178 179static void sched_feat_disable(int i) 180{ 181 if (static_key_enabled(&sched_feat_keys[i])) 182 static_key_slow_dec(&sched_feat_keys[i]); 183} 184 185static void sched_feat_enable(int i) 186{ 187 if (!static_key_enabled(&sched_feat_keys[i])) 188 static_key_slow_inc(&sched_feat_keys[i]); 189} 190#else 191static void sched_feat_disable(int i) { }; 192static void sched_feat_enable(int i) { }; 193#endif /* HAVE_JUMP_LABEL */ 194 195static ssize_t 196sched_feat_write(struct file *filp, const char __user *ubuf, 197 size_t cnt, loff_t *ppos) 198{ 199 char buf[64]; 200 char *cmp; 201 int neg = 0; 202 int i; 203 204 if (cnt > 63) 205 cnt = 63; 206 207 if (copy_from_user(&buf, ubuf, cnt)) 208 return -EFAULT; 209 210 buf[cnt] = 0; 211 cmp = strstrip(buf); 212 213 if (strncmp(cmp, "NO_", 3) == 0) { 214 neg = 1; 215 cmp += 3; 216 } 217 218 for (i = 0; i < __SCHED_FEAT_NR; i++) { 219 if (strcmp(cmp, sched_feat_names[i]) == 0) { 220 if (neg) { 221 sysctl_sched_features &= ~(1UL << i); 222 sched_feat_disable(i); 223 } else { 224 sysctl_sched_features |= (1UL << i); 225 sched_feat_enable(i); 226 } 227 break; 228 } 229 } 230 231 if (i == __SCHED_FEAT_NR) 232 return -EINVAL; 233 234 *ppos += cnt; 235 236 return cnt; 237} 238 239static int sched_feat_open(struct inode *inode, struct file *filp) 240{ 241 return single_open(filp, sched_feat_show, NULL); 242} 243 244static const struct file_operations sched_feat_fops = { 245 .open = sched_feat_open, 246 .write = sched_feat_write, 247 .read = seq_read, 248 .llseek = seq_lseek, 249 .release = single_release, 250}; 251 252static __init int sched_init_debug(void) 253{ 254 debugfs_create_file("sched_features", 0644, NULL, NULL, 255 &sched_feat_fops); 256 257 return 0; 258} 259late_initcall(sched_init_debug); 260#endif /* CONFIG_SCHED_DEBUG */ 261 262/* 263 * Number of tasks to iterate in a single balance run. 264 * Limited because this is done with IRQs disabled. 265 */ 266const_debug unsigned int sysctl_sched_nr_migrate = 32; 267 268/* 269 * period over which we average the RT time consumption, measured 270 * in ms. 271 * 272 * default: 1s 273 */ 274const_debug unsigned int sysctl_sched_time_avg = MSEC_PER_SEC; 275 276/* 277 * period over which we measure -rt task cpu usage in us. 278 * default: 1s 279 */ 280unsigned int sysctl_sched_rt_period = 1000000; 281 282__read_mostly int scheduler_running; 283 284/* 285 * part of the period that we allow rt tasks to run in us. 286 * default: 0.95s 287 */ 288int sysctl_sched_rt_runtime = 950000; 289 290 291 292/* 293 * __task_rq_lock - lock the rq @p resides on. 294 */ 295static inline struct rq *__task_rq_lock(struct task_struct *p) 296 __acquires(rq->lock) 297{ 298 struct rq *rq; 299 300 lockdep_assert_held(&p->pi_lock); 301 302 for (;;) { 303 rq = task_rq(p); 304 raw_spin_lock(&rq->lock); 305 if (likely(rq == task_rq(p))) 306 return rq; 307 raw_spin_unlock(&rq->lock); 308 } 309} 310 311/* 312 * task_rq_lock - lock p->pi_lock and lock the rq @p resides on. 313 */ 314static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags) 315 __acquires(p->pi_lock) 316 __acquires(rq->lock) 317{ 318 struct rq *rq; 319 320 for (;;) { 321 raw_spin_lock_irqsave(&p->pi_lock, *flags); 322 rq = task_rq(p); 323 raw_spin_lock(&rq->lock); 324 if (likely(rq == task_rq(p))) 325 return rq; 326 raw_spin_unlock(&rq->lock); 327 raw_spin_unlock_irqrestore(&p->pi_lock, *flags); 328 } 329} 330 331static void __task_rq_unlock(struct rq *rq) 332 __releases(rq->lock) 333{ 334 raw_spin_unlock(&rq->lock); 335} 336 337static inline void 338task_rq_unlock(struct rq *rq, struct task_struct *p, unsigned long *flags) 339 __releases(rq->lock) 340 __releases(p->pi_lock) 341{ 342 raw_spin_unlock(&rq->lock); 343 raw_spin_unlock_irqrestore(&p->pi_lock, *flags); 344} 345 346/* 347 * this_rq_lock - lock this runqueue and disable interrupts. 348 */ 349static struct rq *this_rq_lock(void) 350 __acquires(rq->lock) 351{ 352 struct rq *rq; 353 354 local_irq_disable(); 355 rq = this_rq(); 356 raw_spin_lock(&rq->lock); 357 358 return rq; 359} 360 361#ifdef CONFIG_SCHED_HRTICK 362/* 363 * Use HR-timers to deliver accurate preemption points. 364 * 365 * Its all a bit involved since we cannot program an hrt while holding the 366 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a 367 * reschedule event. 368 * 369 * When we get rescheduled we reprogram the hrtick_timer outside of the 370 * rq->lock. 371 */ 372 373static void hrtick_clear(struct rq *rq) 374{ 375 if (hrtimer_active(&rq->hrtick_timer)) 376 hrtimer_cancel(&rq->hrtick_timer); 377} 378 379/* 380 * High-resolution timer tick. 381 * Runs from hardirq context with interrupts disabled. 382 */ 383static enum hrtimer_restart hrtick(struct hrtimer *timer) 384{ 385 struct rq *rq = container_of(timer, struct rq, hrtick_timer); 386 387 WARN_ON_ONCE(cpu_of(rq) != smp_processor_id()); 388 389 raw_spin_lock(&rq->lock); 390 update_rq_clock(rq); 391 rq->curr->sched_class->task_tick(rq, rq->curr, 1); 392 raw_spin_unlock(&rq->lock); 393 394 return HRTIMER_NORESTART; 395} 396 397#ifdef CONFIG_SMP 398/* 399 * called from hardirq (IPI) context 400 */ 401static void __hrtick_start(void *arg) 402{ 403 struct rq *rq = arg; 404 405 raw_spin_lock(&rq->lock); 406 hrtimer_restart(&rq->hrtick_timer); 407 rq->hrtick_csd_pending = 0; 408 raw_spin_unlock(&rq->lock); 409} 410 411/* 412 * Called to set the hrtick timer state. 413 * 414 * called with rq->lock held and irqs disabled 415 */ 416void hrtick_start(struct rq *rq, u64 delay) 417{ 418 struct hrtimer *timer = &rq->hrtick_timer; 419 ktime_t time = ktime_add_ns(timer->base->get_time(), delay); 420 421 hrtimer_set_expires(timer, time); 422 423 if (rq == this_rq()) { 424 hrtimer_restart(timer); 425 } else if (!rq->hrtick_csd_pending) { 426 __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd, 0); 427 rq->hrtick_csd_pending = 1; 428 } 429} 430 431static int 432hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu) 433{ 434 int cpu = (int)(long)hcpu; 435 436 switch (action) { 437 case CPU_UP_CANCELED: 438 case CPU_UP_CANCELED_FROZEN: 439 case CPU_DOWN_PREPARE: 440 case CPU_DOWN_PREPARE_FROZEN: 441 case CPU_DEAD: 442 case CPU_DEAD_FROZEN: 443 hrtick_clear(cpu_rq(cpu)); 444 return NOTIFY_OK; 445 } 446 447 return NOTIFY_DONE; 448} 449 450static __init void init_hrtick(void) 451{ 452 hotcpu_notifier(hotplug_hrtick, 0); 453} 454#else 455/* 456 * Called to set the hrtick timer state. 457 * 458 * called with rq->lock held and irqs disabled 459 */ 460void hrtick_start(struct rq *rq, u64 delay) 461{ 462 __hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0, 463 HRTIMER_MODE_REL_PINNED, 0); 464} 465 466static inline void init_hrtick(void) 467{ 468} 469#endif /* CONFIG_SMP */ 470 471static void init_rq_hrtick(struct rq *rq) 472{ 473#ifdef CONFIG_SMP 474 rq->hrtick_csd_pending = 0; 475 476 rq->hrtick_csd.flags = 0; 477 rq->hrtick_csd.func = __hrtick_start; 478 rq->hrtick_csd.info = rq; 479#endif 480 481 hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 482 rq->hrtick_timer.function = hrtick; 483} 484#else /* CONFIG_SCHED_HRTICK */ 485static inline void hrtick_clear(struct rq *rq) 486{ 487} 488 489static inline void init_rq_hrtick(struct rq *rq) 490{ 491} 492 493static inline void init_hrtick(void) 494{ 495} 496#endif /* CONFIG_SCHED_HRTICK */ 497 498/* 499 * resched_task - mark a task 'to be rescheduled now'. 500 * 501 * On UP this means the setting of the need_resched flag, on SMP it 502 * might also involve a cross-CPU call to trigger the scheduler on 503 * the target CPU. 504 */ 505#ifdef CONFIG_SMP 506 507#ifndef tsk_is_polling 508#define tsk_is_polling(t) 0 509#endif 510 511void resched_task(struct task_struct *p) 512{ 513 int cpu; 514 515 assert_raw_spin_locked(&task_rq(p)->lock); 516 517 if (test_tsk_need_resched(p)) 518 return; 519 520 set_tsk_need_resched(p); 521 522 cpu = task_cpu(p); 523 if (cpu == smp_processor_id()) 524 return; 525 526 /* NEED_RESCHED must be visible before we test polling */ 527 smp_mb(); 528 if (!tsk_is_polling(p)) 529 smp_send_reschedule(cpu); 530} 531 532void resched_cpu(int cpu) 533{ 534 struct rq *rq = cpu_rq(cpu); 535 unsigned long flags; 536 537 if (!raw_spin_trylock_irqsave(&rq->lock, flags)) 538 return; 539 resched_task(cpu_curr(cpu)); 540 raw_spin_unlock_irqrestore(&rq->lock, flags); 541} 542 543#ifdef CONFIG_NO_HZ 544/* 545 * In the semi idle case, use the nearest busy cpu for migrating timers 546 * from an idle cpu. This is good for power-savings. 547 * 548 * We don't do similar optimization for completely idle system, as 549 * selecting an idle cpu will add more delays to the timers than intended 550 * (as that cpu's timer base may not be uptodate wrt jiffies etc). 551 */ 552int get_nohz_timer_target(void) 553{ 554 int cpu = smp_processor_id(); 555 int i; 556 struct sched_domain *sd; 557 558 rcu_read_lock(); 559 for_each_domain(cpu, sd) { 560 for_each_cpu(i, sched_domain_span(sd)) { 561 if (!idle_cpu(i)) { 562 cpu = i; 563 goto unlock; 564 } 565 } 566 } 567unlock: 568 rcu_read_unlock(); 569 return cpu; 570} 571/* 572 * When add_timer_on() enqueues a timer into the timer wheel of an 573 * idle CPU then this timer might expire before the next timer event 574 * which is scheduled to wake up that CPU. In case of a completely 575 * idle system the next event might even be infinite time into the 576 * future. wake_up_idle_cpu() ensures that the CPU is woken up and 577 * leaves the inner idle loop so the newly added timer is taken into 578 * account when the CPU goes back to idle and evaluates the timer 579 * wheel for the next timer event. 580 */ 581void wake_up_idle_cpu(int cpu) 582{ 583 struct rq *rq = cpu_rq(cpu); 584 585 if (cpu == smp_processor_id()) 586 return; 587 588 /* 589 * This is safe, as this function is called with the timer 590 * wheel base lock of (cpu) held. When the CPU is on the way 591 * to idle and has not yet set rq->curr to idle then it will 592 * be serialized on the timer wheel base lock and take the new 593 * timer into account automatically. 594 */ 595 if (rq->curr != rq->idle) 596 return; 597 598 /* 599 * We can set TIF_RESCHED on the idle task of the other CPU 600 * lockless. The worst case is that the other CPU runs the 601 * idle task through an additional NOOP schedule() 602 */ 603 set_tsk_need_resched(rq->idle); 604 605 /* NEED_RESCHED must be visible before we test polling */ 606 smp_mb(); 607 if (!tsk_is_polling(rq->idle)) 608 smp_send_reschedule(cpu); 609} 610 611static inline bool got_nohz_idle_kick(void) 612{ 613 int cpu = smp_processor_id(); 614 return idle_cpu(cpu) && test_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu)); 615} 616 617#else /* CONFIG_NO_HZ */ 618 619static inline bool got_nohz_idle_kick(void) 620{ 621 return false; 622} 623 624#endif /* CONFIG_NO_HZ */ 625 626void sched_avg_update(struct rq *rq) 627{ 628 s64 period = sched_avg_period(); 629 630 while ((s64)(rq->clock - rq->age_stamp) > period) { 631 /* 632 * Inline assembly required to prevent the compiler 633 * optimising this loop into a divmod call. 634 * See __iter_div_u64_rem() for another example of this. 635 */ 636 asm("" : "+rm" (rq->age_stamp)); 637 rq->age_stamp += period; 638 rq->rt_avg /= 2; 639 } 640} 641 642#else /* !CONFIG_SMP */ 643void resched_task(struct task_struct *p) 644{ 645 assert_raw_spin_locked(&task_rq(p)->lock); 646 set_tsk_need_resched(p); 647} 648#endif /* CONFIG_SMP */ 649 650#if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \ 651 (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH))) 652/* 653 * Iterate task_group tree rooted at *from, calling @down when first entering a 654 * node and @up when leaving it for the final time. 655 * 656 * Caller must hold rcu_lock or sufficient equivalent. 657 */ 658int walk_tg_tree_from(struct task_group *from, 659 tg_visitor down, tg_visitor up, void *data) 660{ 661 struct task_group *parent, *child; 662 int ret; 663 664 parent = from; 665 666down: 667 ret = (*down)(parent, data); 668 if (ret) 669 goto out; 670 list_for_each_entry_rcu(child, &parent->children, siblings) { 671 parent = child; 672 goto down; 673 674up: 675 continue; 676 } 677 ret = (*up)(parent, data); 678 if (ret || parent == from) 679 goto out; 680 681 child = parent; 682 parent = parent->parent; 683 if (parent) 684 goto up; 685out: 686 return ret; 687} 688 689int tg_nop(struct task_group *tg, void *data) 690{ 691 return 0; 692} 693#endif 694 695static void set_load_weight(struct task_struct *p) 696{ 697 int prio = p->static_prio - MAX_RT_PRIO; 698 struct load_weight *load = &p->se.load; 699 700 /* 701 * SCHED_IDLE tasks get minimal weight: 702 */ 703 if (p->policy == SCHED_IDLE) { 704 load->weight = scale_load(WEIGHT_IDLEPRIO); 705 load->inv_weight = WMULT_IDLEPRIO; 706 return; 707 } 708 709 load->weight = scale_load(prio_to_weight[prio]); 710 load->inv_weight = prio_to_wmult[prio]; 711} 712 713static void enqueue_task(struct rq *rq, struct task_struct *p, int flags) 714{ 715 update_rq_clock(rq); 716 sched_info_queued(p); 717 p->sched_class->enqueue_task(rq, p, flags); 718} 719 720static void dequeue_task(struct rq *rq, struct task_struct *p, int flags) 721{ 722 update_rq_clock(rq); 723 sched_info_dequeued(p); 724 p->sched_class->dequeue_task(rq, p, flags); 725} 726 727void activate_task(struct rq *rq, struct task_struct *p, int flags) 728{ 729 if (task_contributes_to_load(p)) 730 rq->nr_uninterruptible--; 731 732 enqueue_task(rq, p, flags); 733} 734 735void deactivate_task(struct rq *rq, struct task_struct *p, int flags) 736{ 737 if (task_contributes_to_load(p)) 738 rq->nr_uninterruptible++; 739 740 dequeue_task(rq, p, flags); 741} 742 743static void update_rq_clock_task(struct rq *rq, s64 delta) 744{ 745/* 746 * In theory, the compile should just see 0 here, and optimize out the call 747 * to sched_rt_avg_update. But I don't trust it... 748 */ 749#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) 750 s64 steal = 0, irq_delta = 0; 751#endif 752#ifdef CONFIG_IRQ_TIME_ACCOUNTING 753 irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time; 754 755 /* 756 * Since irq_time is only updated on {soft,}irq_exit, we might run into 757 * this case when a previous update_rq_clock() happened inside a 758 * {soft,}irq region. 759 * 760 * When this happens, we stop ->clock_task and only update the 761 * prev_irq_time stamp to account for the part that fit, so that a next 762 * update will consume the rest. This ensures ->clock_task is 763 * monotonic. 764 * 765 * It does however cause some slight miss-attribution of {soft,}irq 766 * time, a more accurate solution would be to update the irq_time using 767 * the current rq->clock timestamp, except that would require using 768 * atomic ops. 769 */ 770 if (irq_delta > delta) 771 irq_delta = delta; 772 773 rq->prev_irq_time += irq_delta; 774 delta -= irq_delta; 775#endif 776#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING 777 if (static_key_false((¶virt_steal_rq_enabled))) { 778 u64 st; 779 780 steal = paravirt_steal_clock(cpu_of(rq)); 781 steal -= rq->prev_steal_time_rq; 782 783 if (unlikely(steal > delta)) 784 steal = delta; 785 786 st = steal_ticks(steal); 787 steal = st * TICK_NSEC; 788 789 rq->prev_steal_time_rq += steal; 790 791 delta -= steal; 792 } 793#endif 794 795 rq->clock_task += delta; 796 797#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) 798 if ((irq_delta + steal) && sched_feat(NONTASK_POWER)) 799 sched_rt_avg_update(rq, irq_delta + steal); 800#endif 801} 802 803void sched_set_stop_task(int cpu, struct task_struct *stop) 804{ 805 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 }; 806 struct task_struct *old_stop = cpu_rq(cpu)->stop; 807 808 if (stop) { 809 /* 810 * Make it appear like a SCHED_FIFO task, its something 811 * userspace knows about and won't get confused about. 812 * 813 * Also, it will make PI more or less work without too 814 * much confusion -- but then, stop work should not 815 * rely on PI working anyway. 816 */ 817 sched_setscheduler_nocheck(stop, SCHED_FIFO, ¶m); 818 819 stop->sched_class = &stop_sched_class; 820 } 821 822 cpu_rq(cpu)->stop = stop; 823 824 if (old_stop) { 825 /* 826 * Reset it back to a normal scheduling class so that 827 * it can die in pieces. 828 */ 829 old_stop->sched_class = &rt_sched_class; 830 } 831} 832 833/* 834 * __normal_prio - return the priority that is based on the static prio 835 */ 836static inline int __normal_prio(struct task_struct *p) 837{ 838 return p->static_prio; 839} 840 841/* 842 * Calculate the expected normal priority: i.e. priority 843 * without taking RT-inheritance into account. Might be 844 * boosted by interactivity modifiers. Changes upon fork, 845 * setprio syscalls, and whenever the interactivity 846 * estimator recalculates. 847 */ 848static inline int normal_prio(struct task_struct *p) 849{ 850 int prio; 851 852 if (task_has_rt_policy(p)) 853 prio = MAX_RT_PRIO-1 - p->rt_priority; 854 else 855 prio = __normal_prio(p); 856 return prio; 857} 858 859/* 860 * Calculate the current priority, i.e. the priority 861 * taken into account by the scheduler. This value might 862 * be boosted by RT tasks, or might be boosted by 863 * interactivity modifiers. Will be RT if the task got 864 * RT-boosted. If not then it returns p->normal_prio. 865 */ 866static int effective_prio(struct task_struct *p) 867{ 868 p->normal_prio = normal_prio(p); 869 /* 870 * If we are RT tasks or we were boosted to RT priority, 871 * keep the priority unchanged. Otherwise, update priority 872 * to the normal priority: 873 */ 874 if (!rt_prio(p->prio)) 875 return p->normal_prio; 876 return p->prio; 877} 878 879/** 880 * task_curr - is this task currently executing on a CPU? 881 * @p: the task in question. 882 */ 883inline int task_curr(const struct task_struct *p) 884{ 885 return cpu_curr(task_cpu(p)) == p; 886} 887 888static inline void check_class_changed(struct rq *rq, struct task_struct *p, 889 const struct sched_class *prev_class, 890 int oldprio) 891{ 892 if (prev_class != p->sched_class) { 893 if (prev_class->switched_from) 894 prev_class->switched_from(rq, p); 895 p->sched_class->switched_to(rq, p); 896 } else if (oldprio != p->prio) 897 p->sched_class->prio_changed(rq, p, oldprio); 898} 899 900void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags) 901{ 902 const struct sched_class *class; 903 904 if (p->sched_class == rq->curr->sched_class) { 905 rq->curr->sched_class->check_preempt_curr(rq, p, flags); 906 } else { 907 for_each_class(class) { 908 if (class == rq->curr->sched_class) 909 break; 910 if (class == p->sched_class) { 911 resched_task(rq->curr); 912 break; 913 } 914 } 915 } 916 917 /* 918 * A queue event has occurred, and we're going to schedule. In 919 * this case, we can save a useless back to back clock update. 920 */ 921 if (rq->curr->on_rq && test_tsk_need_resched(rq->curr)) 922 rq->skip_clock_update = 1; 923} 924 925#ifdef CONFIG_SMP 926void set_task_cpu(struct task_struct *p, unsigned int new_cpu) 927{ 928#ifdef CONFIG_SCHED_DEBUG 929 /* 930 * We should never call set_task_cpu() on a blocked task, 931 * ttwu() will sort out the placement. 932 */ 933 WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING && 934 !(task_thread_info(p)->preempt_count & PREEMPT_ACTIVE)); 935 936#ifdef CONFIG_LOCKDEP 937 /* 938 * The caller should hold either p->pi_lock or rq->lock, when changing 939 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks. 940 * 941 * sched_move_task() holds both and thus holding either pins the cgroup, 942 * see task_group(). 943 * 944 * Furthermore, all task_rq users should acquire both locks, see 945 * task_rq_lock(). 946 */ 947 WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) || 948 lockdep_is_held(&task_rq(p)->lock))); 949#endif 950#endif 951 952 trace_sched_migrate_task(p, new_cpu); 953 954 if (task_cpu(p) != new_cpu) { 955 p->se.nr_migrations++; 956 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, 1, NULL, 0); 957 } 958 959 __set_task_cpu(p, new_cpu); 960} 961 962struct migration_arg { 963 struct task_struct *task; 964 int dest_cpu; 965}; 966 967static int migration_cpu_stop(void *data); 968 969/* 970 * wait_task_inactive - wait for a thread to unschedule. 971 * 972 * If @match_state is nonzero, it's the @p->state value just checked and 973 * not expected to change. If it changes, i.e. @p might have woken up, 974 * then return zero. When we succeed in waiting for @p to be off its CPU, 975 * we return a positive number (its total switch count). If a second call 976 * a short while later returns the same number, the caller can be sure that 977 * @p has remained unscheduled the whole time. 978 * 979 * The caller must ensure that the task *will* unschedule sometime soon, 980 * else this function might spin for a *long* time. This function can't 981 * be called with interrupts off, or it may introduce deadlock with 982 * smp_call_function() if an IPI is sent by the same process we are 983 * waiting to become inactive. 984 */ 985unsigned long wait_task_inactive(struct task_struct *p, long match_state) 986{ 987 unsigned long flags; 988 int running, on_rq; 989 unsigned long ncsw; 990 struct rq *rq; 991 992 for (;;) { 993 /* 994 * We do the initial early heuristics without holding 995 * any task-queue locks at all. We'll only try to get 996 * the runqueue lock when things look like they will 997 * work out! 998 */ 999 rq = task_rq(p); 1000 1001 /* 1002 * If the task is actively running on another CPU 1003 * still, just relax and busy-wait without holding 1004 * any locks. 1005 * 1006 * NOTE! Since we don't hold any locks, it's not 1007 * even sure that "rq" stays as the right runqueue! 1008 * But we don't care, since "task_running()" will 1009 * return false if the runqueue has changed and p 1010 * is actually now running somewhere else! 1011 */ 1012 while (task_running(rq, p)) { 1013 if (match_state && unlikely(p->state != match_state)) 1014 return 0; 1015 cpu_relax(); 1016 } 1017 1018 /* 1019 * Ok, time to look more closely! We need the rq 1020 * lock now, to be *sure*. If we're wrong, we'll 1021 * just go back and repeat. 1022 */ 1023 rq = task_rq_lock(p, &flags); 1024 trace_sched_wait_task(p); 1025 running = task_running(rq, p); 1026 on_rq = p->on_rq; 1027 ncsw = 0; 1028 if (!match_state || p->state == match_state) 1029 ncsw = p->nvcsw | LONG_MIN; /* sets MSB */ 1030 task_rq_unlock(rq, p, &flags); 1031 1032 /* 1033 * If it changed from the expected state, bail out now. 1034 */ 1035 if (unlikely(!ncsw)) 1036 break; 1037 1038 /* 1039 * Was it really running after all now that we 1040 * checked with the proper locks actually held? 1041 * 1042 * Oops. Go back and try again.. 1043 */ 1044 if (unlikely(running)) { 1045 cpu_relax(); 1046 continue; 1047 } 1048 1049 /* 1050 * It's not enough that it's not actively running, 1051 * it must be off the runqueue _entirely_, and not 1052 * preempted! 1053 * 1054 * So if it was still runnable (but just not actively 1055 * running right now), it's preempted, and we should 1056 * yield - it could be a while. 1057 */ 1058 if (unlikely(on_rq)) { 1059 ktime_t to = ktime_set(0, NSEC_PER_SEC/HZ); 1060 1061 set_current_state(TASK_UNINTERRUPTIBLE); 1062 schedule_hrtimeout(&to, HRTIMER_MODE_REL); 1063 continue; 1064 } 1065 1066 /* 1067 * Ahh, all good. It wasn't running, and it wasn't 1068 * runnable, which means that it will never become 1069 * running in the future either. We're all done! 1070 */ 1071 break; 1072 } 1073 1074 return ncsw; 1075} 1076 1077/*** 1078 * kick_process - kick a running thread to enter/exit the kernel 1079 * @p: the to-be-kicked thread 1080 * 1081 * Cause a process which is running on another CPU to enter 1082 * kernel-mode, without any delay. (to get signals handled.) 1083 * 1084 * NOTE: this function doesn't have to take the runqueue lock, 1085 * because all it wants to ensure is that the remote task enters 1086 * the kernel. If the IPI races and the task has been migrated 1087 * to another CPU then no harm is done and the purpose has been 1088 * achieved as well. 1089 */ 1090void kick_process(struct task_struct *p) 1091{ 1092 int cpu; 1093 1094 preempt_disable(); 1095 cpu = task_cpu(p); 1096 if ((cpu != smp_processor_id()) && task_curr(p)) 1097 smp_send_reschedule(cpu); 1098 preempt_enable(); 1099} 1100EXPORT_SYMBOL_GPL(kick_process); 1101#endif /* CONFIG_SMP */ 1102 1103#ifdef CONFIG_SMP 1104/* 1105 * ->cpus_allowed is protected by both rq->lock and p->pi_lock 1106 */ 1107static int select_fallback_rq(int cpu, struct task_struct *p) 1108{ 1109 const struct cpumask *nodemask = cpumask_of_node(cpu_to_node(cpu)); 1110 enum { cpuset, possible, fail } state = cpuset; 1111 int dest_cpu; 1112 1113 /* Look for allowed, online CPU in same node. */ 1114 for_each_cpu(dest_cpu, nodemask) { 1115 if (!cpu_online(dest_cpu)) 1116 continue; 1117 if (!cpu_active(dest_cpu)) 1118 continue; 1119 if (cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) 1120 return dest_cpu; 1121 } 1122 1123 for (;;) { 1124 /* Any allowed, online CPU? */ 1125 for_each_cpu(dest_cpu, tsk_cpus_allowed(p)) { 1126 if (!cpu_online(dest_cpu)) 1127 continue; 1128 if (!cpu_active(dest_cpu)) 1129 continue; 1130 goto out; 1131 } 1132 1133 switch (state) { 1134 case cpuset: 1135 /* No more Mr. Nice Guy. */ 1136 cpuset_cpus_allowed_fallback(p); 1137 state = possible; 1138 break; 1139 1140 case possible: 1141 do_set_cpus_allowed(p, cpu_possible_mask); 1142 state = fail; 1143 break; 1144 1145 case fail: 1146 BUG(); 1147 break; 1148 } 1149 } 1150 1151out: 1152 if (state != cpuset) { 1153 /* 1154 * Don't tell them about moving exiting tasks or 1155 * kernel threads (both mm NULL), since they never 1156 * leave kernel. 1157 */ 1158 if (p->mm && printk_ratelimit()) { 1159 printk_sched("process %d (%s) no longer affine to cpu%d\n", 1160 task_pid_nr(p), p->comm, cpu); 1161 } 1162 } 1163 1164 return dest_cpu; 1165} 1166 1167/* 1168 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable. 1169 */ 1170static inline 1171int select_task_rq(struct task_struct *p, int sd_flags, int wake_flags) 1172{ 1173 int cpu = p->sched_class->select_task_rq(p, sd_flags, wake_flags); 1174 1175 /* 1176 * In order not to call set_task_cpu() on a blocking task we need 1177 * to rely on ttwu() to place the task on a valid ->cpus_allowed 1178 * cpu. 1179 * 1180 * Since this is common to all placement strategies, this lives here. 1181 * 1182 * [ this allows ->select_task() to simply return task_cpu(p) and 1183 * not worry about this generic constraint ] 1184 */ 1185 if (unlikely(!cpumask_test_cpu(cpu, tsk_cpus_allowed(p)) || 1186 !cpu_online(cpu))) 1187 cpu = select_fallback_rq(task_cpu(p), p); 1188 1189 return cpu; 1190} 1191 1192static void update_avg(u64 *avg, u64 sample) 1193{ 1194 s64 diff = sample - *avg; 1195 *avg += diff >> 3; 1196} 1197#endif 1198 1199static void 1200ttwu_stat(struct task_struct *p, int cpu, int wake_flags) 1201{ 1202#ifdef CONFIG_SCHEDSTATS 1203 struct rq *rq = this_rq(); 1204 1205#ifdef CONFIG_SMP 1206 int this_cpu = smp_processor_id(); 1207 1208 if (cpu == this_cpu) { 1209 schedstat_inc(rq, ttwu_local); 1210 schedstat_inc(p, se.statistics.nr_wakeups_local); 1211 } else { 1212 struct sched_domain *sd; 1213 1214 schedstat_inc(p, se.statistics.nr_wakeups_remote); 1215 rcu_read_lock(); 1216 for_each_domain(this_cpu, sd) { 1217 if (cpumask_test_cpu(cpu, sched_domain_span(sd))) { 1218 schedstat_inc(sd, ttwu_wake_remote); 1219 break; 1220 } 1221 } 1222 rcu_read_unlock(); 1223 } 1224 1225 if (wake_flags & WF_MIGRATED) 1226 schedstat_inc(p, se.statistics.nr_wakeups_migrate); 1227 1228#endif /* CONFIG_SMP */ 1229 1230 schedstat_inc(rq, ttwu_count); 1231 schedstat_inc(p, se.statistics.nr_wakeups); 1232 1233 if (wake_flags & WF_SYNC) 1234 schedstat_inc(p, se.statistics.nr_wakeups_sync); 1235 1236#endif /* CONFIG_SCHEDSTATS */ 1237} 1238 1239static void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags) 1240{ 1241 activate_task(rq, p, en_flags); 1242 p->on_rq = 1; 1243 1244 /* if a worker is waking up, notify workqueue */ 1245 if (p->flags & PF_WQ_WORKER) 1246 wq_worker_waking_up(p, cpu_of(rq)); 1247} 1248 1249/* 1250 * Mark the task runnable and perform wakeup-preemption. 1251 */ 1252static void 1253ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags) 1254{ 1255 trace_sched_wakeup(p, true); 1256 check_preempt_curr(rq, p, wake_flags); 1257 1258 p->state = TASK_RUNNING; 1259#ifdef CONFIG_SMP 1260 if (p->sched_class->task_woken) 1261 p->sched_class->task_woken(rq, p); 1262 1263 if (rq->idle_stamp) { 1264 u64 delta = rq->clock - rq->idle_stamp; 1265 u64 max = 2*sysctl_sched_migration_cost; 1266 1267 if (delta > max) 1268 rq->avg_idle = max; 1269 else 1270 update_avg(&rq->avg_idle, delta); 1271 rq->idle_stamp = 0; 1272 } 1273#endif 1274} 1275 1276static void 1277ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags) 1278{ 1279#ifdef CONFIG_SMP 1280 if (p->sched_contributes_to_load) 1281 rq->nr_uninterruptible--; 1282#endif 1283 1284 ttwu_activate(rq, p, ENQUEUE_WAKEUP | ENQUEUE_WAKING); 1285 ttwu_do_wakeup(rq, p, wake_flags); 1286} 1287 1288/* 1289 * Called in case the task @p isn't fully descheduled from its runqueue, 1290 * in this case we must do a remote wakeup. Its a 'light' wakeup though, 1291 * since all we need to do is flip p->state to TASK_RUNNING, since 1292 * the task is still ->on_rq. 1293 */ 1294static int ttwu_remote(struct task_struct *p, int wake_flags) 1295{ 1296 struct rq *rq; 1297 int ret = 0; 1298 1299 rq = __task_rq_lock(p); 1300 if (p->on_rq) { 1301 ttwu_do_wakeup(rq, p, wake_flags); 1302 ret = 1; 1303 } 1304 __task_rq_unlock(rq); 1305 1306 return ret; 1307} 1308 1309#ifdef CONFIG_SMP 1310static void sched_ttwu_pending(void) 1311{ 1312 struct rq *rq = this_rq(); 1313 struct llist_node *llist = llist_del_all(&rq->wake_list); 1314 struct task_struct *p; 1315 1316 raw_spin_lock(&rq->lock); 1317 1318 while (llist) { 1319 p = llist_entry(llist, struct task_struct, wake_entry); 1320 llist = llist_next(llist); 1321 ttwu_do_activate(rq, p, 0); 1322 } 1323 1324 raw_spin_unlock(&rq->lock); 1325} 1326 1327void scheduler_ipi(void) 1328{ 1329 if (llist_empty(&this_rq()->wake_list) && !got_nohz_idle_kick()) 1330 return; 1331 1332 /* 1333 * Not all reschedule IPI handlers call irq_enter/irq_exit, since 1334 * traditionally all their work was done from the interrupt return 1335 * path. Now that we actually do some work, we need to make sure 1336 * we do call them. 1337 * 1338 * Some archs already do call them, luckily irq_enter/exit nest 1339 * properly. 1340 * 1341 * Arguably we should visit all archs and update all handlers, 1342 * however a fair share of IPIs are still resched only so this would 1343 * somewhat pessimize the simple resched case. 1344 */ 1345 irq_enter(); 1346 sched_ttwu_pending(); 1347 1348 /* 1349 * Check if someone kicked us for doing the nohz idle load balance. 1350 */ 1351 if (unlikely(got_nohz_idle_kick() && !need_resched())) { 1352 this_rq()->idle_balance = 1; 1353 raise_softirq_irqoff(SCHED_SOFTIRQ); 1354 } 1355 irq_exit(); 1356} 1357 1358static void ttwu_queue_remote(struct task_struct *p, int cpu) 1359{ 1360 if (llist_add(&p->wake_entry, &cpu_rq(cpu)->wake_list)) 1361 smp_send_reschedule(cpu); 1362} 1363 1364bool cpus_share_cache(int this_cpu, int that_cpu) 1365{ 1366 return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu); 1367} 1368#endif /* CONFIG_SMP */ 1369 1370static void ttwu_queue(struct task_struct *p, int cpu) 1371{ 1372 struct rq *rq = cpu_rq(cpu); 1373 1374#if defined(CONFIG_SMP) 1375 if (sched_feat(TTWU_QUEUE) && !cpus_share_cache(smp_processor_id(), cpu)) { 1376 sched_clock_cpu(cpu); /* sync clocks x-cpu */ 1377 ttwu_queue_remote(p, cpu); 1378 return; 1379 } 1380#endif 1381 1382 raw_spin_lock(&rq->lock); 1383 ttwu_do_activate(rq, p, 0); 1384 raw_spin_unlock(&rq->lock); 1385} 1386 1387/** 1388 * try_to_wake_up - wake up a thread 1389 * @p: the thread to be awakened 1390 * @state: the mask of task states that can be woken 1391 * @wake_flags: wake modifier flags (WF_*) 1392 * 1393 * Put it on the run-queue if it's not already there. The "current" 1394 * thread is always on the run-queue (except when the actual 1395 * re-schedule is in progress), and as such you're allowed to do 1396 * the simpler "current->state = TASK_RUNNING" to mark yourself 1397 * runnable without the overhead of this. 1398 * 1399 * Returns %true if @p was woken up, %false if it was already running 1400 * or @state didn't match @p's state. 1401 */ 1402static int 1403try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) 1404{ 1405 unsigned long flags; 1406 int cpu, success = 0; 1407 1408 smp_wmb(); 1409 raw_spin_lock_irqsave(&p->pi_lock, flags); 1410 if (!(p->state & state)) 1411 goto out; 1412 1413 success = 1; /* we're going to change ->state */ 1414 cpu = task_cpu(p); 1415 1416 if (p->on_rq && ttwu_remote(p, wake_flags)) 1417 goto stat; 1418 1419#ifdef CONFIG_SMP 1420 /* 1421 * If the owning (remote) cpu is still in the middle of schedule() with 1422 * this task as prev, wait until its done referencing the task. 1423 */ 1424 while (p->on_cpu) 1425 cpu_relax(); 1426 /* 1427 * Pairs with the smp_wmb() in finish_lock_switch(). 1428 */ 1429 smp_rmb(); 1430 1431 p->sched_contributes_to_load = !!task_contributes_to_load(p); 1432 p->state = TASK_WAKING; 1433 1434 if (p->sched_class->task_waking) 1435 p->sched_class->task_waking(p); 1436 1437 cpu = select_task_rq(p, SD_BALANCE_WAKE, wake_flags); 1438 if (task_cpu(p) != cpu) { 1439 wake_flags |= WF_MIGRATED; 1440 set_task_cpu(p, cpu); 1441 } 1442#endif /* CONFIG_SMP */ 1443 1444 ttwu_queue(p, cpu); 1445stat: 1446 ttwu_stat(p, cpu, wake_flags); 1447out: 1448 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 1449 1450 return success; 1451} 1452 1453/** 1454 * try_to_wake_up_local - try to wake up a local task with rq lock held 1455 * @p: the thread to be awakened 1456 * 1457 * Put @p on the run-queue if it's not already there. The caller must 1458 * ensure that this_rq() is locked, @p is bound to this_rq() and not 1459 * the current task. 1460 */ 1461static void try_to_wake_up_local(struct task_struct *p) 1462{ 1463 struct rq *rq = task_rq(p); 1464 1465 BUG_ON(rq != this_rq()); 1466 BUG_ON(p == current); 1467 lockdep_assert_held(&rq->lock); 1468 1469 if (!raw_spin_trylock(&p->pi_lock)) { 1470 raw_spin_unlock(&rq->lock); 1471 raw_spin_lock(&p->pi_lock); 1472 raw_spin_lock(&rq->lock); 1473 } 1474 1475 if (!(p->state & TASK_NORMAL)) 1476 goto out; 1477 1478 if (!p->on_rq) 1479 ttwu_activate(rq, p, ENQUEUE_WAKEUP); 1480 1481 ttwu_do_wakeup(rq, p, 0); 1482 ttwu_stat(p, smp_processor_id(), 0); 1483out: 1484 raw_spin_unlock(&p->pi_lock); 1485} 1486 1487/** 1488 * wake_up_process - Wake up a specific process 1489 * @p: The process to be woken up. 1490 * 1491 * Attempt to wake up the nominated process and move it to the set of runnable 1492 * processes. Returns 1 if the process was woken up, 0 if it was already 1493 * running. 1494 * 1495 * It may be assumed that this function implies a write memory barrier before 1496 * changing the task state if and only if any tasks are woken up. 1497 */ 1498int wake_up_process(struct task_struct *p) 1499{ 1500 return try_to_wake_up(p, TASK_ALL, 0); 1501} 1502EXPORT_SYMBOL(wake_up_process); 1503 1504int wake_up_state(struct task_struct *p, unsigned int state) 1505{ 1506 return try_to_wake_up(p, state, 0); 1507} 1508 1509/* 1510 * Perform scheduler related setup for a newly forked process p. 1511 * p is forked by current. 1512 * 1513 * __sched_fork() is basic setup used by init_idle() too: 1514 */ 1515static void __sched_fork(struct task_struct *p) 1516{ 1517 p->on_rq = 0; 1518 1519 p->se.on_rq = 0; 1520 p->se.exec_start = 0; 1521 p->se.sum_exec_runtime = 0; 1522 p->se.prev_sum_exec_runtime = 0; 1523 p->se.nr_migrations = 0; 1524 p->se.vruntime = 0; 1525 INIT_LIST_HEAD(&p->se.group_node); 1526 1527#ifdef CONFIG_SCHEDSTATS 1528 memset(&p->se.statistics, 0, sizeof(p->se.statistics)); 1529#endif 1530 1531 INIT_LIST_HEAD(&p->rt.run_list); 1532 1533#ifdef CONFIG_PREEMPT_NOTIFIERS 1534 INIT_HLIST_HEAD(&p->preempt_notifiers); 1535#endif 1536 1537#ifdef CONFIG_NUMA_BALANCING 1538 if (p->mm && atomic_read(&p->mm->mm_users) == 1) { 1539 p->mm->numa_next_scan = jiffies; 1540 p->mm->numa_next_reset = jiffies; 1541 p->mm->numa_scan_seq = 0; 1542 } 1543 1544 p->node_stamp = 0ULL; 1545 p->numa_scan_seq = p->mm ? p->mm->numa_scan_seq : 0; 1546 p->numa_migrate_seq = p->mm ? p->mm->numa_scan_seq - 1 : 0; 1547 p->numa_scan_period = sysctl_numa_balancing_scan_delay; 1548 p->numa_work.next = &p->numa_work; 1549#endif /* CONFIG_NUMA_BALANCING */ 1550} 1551 1552/* 1553 * fork()/clone()-time setup: 1554 */ 1555void sched_fork(struct task_struct *p) 1556{ 1557 unsigned long flags; 1558 int cpu = get_cpu(); 1559 1560 __sched_fork(p); 1561 /* 1562 * We mark the process as running here. This guarantees that 1563 * nobody will actually run it, and a signal or other external 1564 * event cannot wake it up and insert it on the runqueue either. 1565 */ 1566 p->state = TASK_RUNNING; 1567 1568 /* 1569 * Make sure we do not leak PI boosting priority to the child. 1570 */ 1571 p->prio = current->normal_prio; 1572 1573 /* 1574 * Revert to default priority/policy on fork if requested. 1575 */ 1576 if (unlikely(p->sched_reset_on_fork)) { 1577 if (task_has_rt_policy(p)) { 1578 p->policy = SCHED_NORMAL; 1579 p->static_prio = NICE_TO_PRIO(0); 1580 p->rt_priority = 0; 1581 } else if (PRIO_TO_NICE(p->static_prio) < 0) 1582 p->static_prio = NICE_TO_PRIO(0); 1583 1584 p->prio = p->normal_prio = __normal_prio(p); 1585 set_load_weight(p); 1586 1587 /* 1588 * We don't need the reset flag anymore after the fork. It has 1589 * fulfilled its duty: 1590 */ 1591 p->sched_reset_on_fork = 0; 1592 } 1593 1594 if (!rt_prio(p->prio)) 1595 p->sched_class = &fair_sched_class; 1596 1597 if (p->sched_class->task_fork) 1598 p->sched_class->task_fork(p); 1599 1600 /* 1601 * The child is not yet in the pid-hash so no cgroup attach races, 1602 * and the cgroup is pinned to this child due to cgroup_fork() 1603 * is ran before sched_fork(). 1604 * 1605 * Silence PROVE_RCU. 1606 */ 1607 raw_spin_lock_irqsave(&p->pi_lock, flags); 1608 set_task_cpu(p, cpu); 1609 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 1610 1611#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) 1612 if (likely(sched_info_on())) 1613 memset(&p->sched_info, 0, sizeof(p->sched_info)); 1614#endif 1615#if defined(CONFIG_SMP) 1616 p->on_cpu = 0; 1617#endif 1618#ifdef CONFIG_PREEMPT_COUNT 1619 /* Want to start with kernel preemption disabled. */ 1620 task_thread_info(p)->preempt_count = 1; 1621#endif 1622#ifdef CONFIG_SMP 1623 plist_node_init(&p->pushable_tasks, MAX_PRIO); 1624#endif 1625 1626 put_cpu(); 1627} 1628 1629/* 1630 * wake_up_new_task - wake up a newly created task for the first time. 1631 * 1632 * This function will do some initial scheduler statistics housekeeping 1633 * that must be done for every newly created context, then puts the task 1634 * on the runqueue and wakes it. 1635 */ 1636void wake_up_new_task(struct task_struct *p) 1637{ 1638 unsigned long flags; 1639 struct rq *rq; 1640 1641 raw_spin_lock_irqsave(&p->pi_lock, flags); 1642#ifdef CONFIG_SMP 1643 /* 1644 * Fork balancing, do it here and not earlier because: 1645 * - cpus_allowed can change in the fork path 1646 * - any previously selected cpu might disappear through hotplug 1647 */ 1648 set_task_cpu(p, select_task_rq(p, SD_BALANCE_FORK, 0)); 1649#endif 1650 1651 rq = __task_rq_lock(p); 1652 activate_task(rq, p, 0); 1653 p->on_rq = 1; 1654 trace_sched_wakeup_new(p, true); 1655 check_preempt_curr(rq, p, WF_FORK); 1656#ifdef CONFIG_SMP 1657 if (p->sched_class->task_woken) 1658 p->sched_class->task_woken(rq, p); 1659#endif 1660 task_rq_unlock(rq, p, &flags); 1661} 1662 1663#ifdef CONFIG_PREEMPT_NOTIFIERS 1664 1665/** 1666 * preempt_notifier_register - tell me when current is being preempted & rescheduled 1667 * @notifier: notifier struct to register 1668 */ 1669void preempt_notifier_register(struct preempt_notifier *notifier) 1670{ 1671 hlist_add_head(¬ifier->link, ¤t->preempt_notifiers); 1672} 1673EXPORT_SYMBOL_GPL(preempt_notifier_register); 1674 1675/** 1676 * preempt_notifier_unregister - no longer interested in preemption notifications 1677 * @notifier: notifier struct to unregister 1678 * 1679 * This is safe to call from within a preemption notifier. 1680 */ 1681void preempt_notifier_unregister(struct preempt_notifier *notifier) 1682{ 1683 hlist_del(¬ifier->link); 1684} 1685EXPORT_SYMBOL_GPL(preempt_notifier_unregister); 1686 1687static void fire_sched_in_preempt_notifiers(struct task_struct *curr) 1688{ 1689 struct preempt_notifier *notifier; 1690 struct hlist_node *node; 1691 1692 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link) 1693 notifier->ops->sched_in(notifier, raw_smp_processor_id()); 1694} 1695 1696static void 1697fire_sched_out_preempt_notifiers(struct task_struct *curr, 1698 struct task_struct *next) 1699{ 1700 struct preempt_notifier *notifier; 1701 struct hlist_node *node; 1702 1703 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link) 1704 notifier->ops->sched_out(notifier, next); 1705} 1706 1707#else /* !CONFIG_PREEMPT_NOTIFIERS */ 1708 1709static void fire_sched_in_preempt_notifiers(struct task_struct *curr) 1710{ 1711} 1712 1713static void 1714fire_sched_out_preempt_notifiers(struct task_struct *curr, 1715 struct task_struct *next) 1716{ 1717} 1718 1719#endif /* CONFIG_PREEMPT_NOTIFIERS */ 1720 1721/** 1722 * prepare_task_switch - prepare to switch tasks 1723 * @rq: the runqueue preparing to switch 1724 * @prev: the current task that is being switched out 1725 * @next: the task we are going to switch to. 1726 * 1727 * This is called with the rq lock held and interrupts off. It must 1728 * be paired with a subsequent finish_task_switch after the context 1729 * switch. 1730 * 1731 * prepare_task_switch sets up locking and calls architecture specific 1732 * hooks. 1733 */ 1734static inline void 1735prepare_task_switch(struct rq *rq, struct task_struct *prev, 1736 struct task_struct *next) 1737{ 1738 trace_sched_switch(prev, next); 1739 sched_info_switch(prev, next); 1740 perf_event_task_sched_out(prev, next); 1741 fire_sched_out_preempt_notifiers(prev, next); 1742 prepare_lock_switch(rq, next); 1743 prepare_arch_switch(next); 1744} 1745 1746/** 1747 * finish_task_switch - clean up after a task-switch 1748 * @rq: runqueue associated with task-switch 1749 * @prev: the thread we just switched away from. 1750 * 1751 * finish_task_switch must be called after the context switch, paired 1752 * with a prepare_task_switch call before the context switch. 1753 * finish_task_switch will reconcile locking set up by prepare_task_switch, 1754 * and do any other architecture-specific cleanup actions. 1755 * 1756 * Note that we may have delayed dropping an mm in context_switch(). If 1757 * so, we finish that here outside of the runqueue lock. (Doing it 1758 * with the lock held can cause deadlocks; see schedule() for 1759 * details.) 1760 */ 1761static void finish_task_switch(struct rq *rq, struct task_struct *prev) 1762 __releases(rq->lock) 1763{ 1764 struct mm_struct *mm = rq->prev_mm; 1765 long prev_state; 1766 1767 rq->prev_mm = NULL; 1768 1769 /* 1770 * A task struct has one reference for the use as "current". 1771 * If a task dies, then it sets TASK_DEAD in tsk->state and calls 1772 * schedule one last time. The schedule call will never return, and 1773 * the scheduled task must drop that reference. 1774 * The test for TASK_DEAD must occur while the runqueue locks are 1775 * still held, otherwise prev could be scheduled on another cpu, die 1776 * there before we look at prev->state, and then the reference would 1777 * be dropped twice. 1778 * Manfred Spraul <manfred@colorfullife.com> 1779 */ 1780 prev_state = prev->state; 1781 vtime_task_switch(prev); 1782 finish_arch_switch(prev); 1783 perf_event_task_sched_in(prev, current); 1784 finish_lock_switch(rq, prev); 1785 finish_arch_post_lock_switch(); 1786 1787 fire_sched_in_preempt_notifiers(current); 1788 if (mm) 1789 mmdrop(mm); 1790 if (unlikely(prev_state == TASK_DEAD)) { 1791 /* 1792 * Remove function-return probe instances associated with this 1793 * task and put them back on the free list. 1794 */ 1795 kprobe_flush_task(prev); 1796 put_task_struct(prev); 1797 } 1798} 1799 1800#ifdef CONFIG_SMP 1801 1802/* assumes rq->lock is held */ 1803static inline void pre_schedule(struct rq *rq, struct task_struct *prev) 1804{ 1805 if (prev->sched_class->pre_schedule) 1806 prev->sched_class->pre_schedule(rq, prev); 1807} 1808 1809/* rq->lock is NOT held, but preemption is disabled */ 1810static inline void post_schedule(struct rq *rq) 1811{ 1812 if (rq->post_schedule) { 1813 unsigned long flags; 1814 1815 raw_spin_lock_irqsave(&rq->lock, flags); 1816 if (rq->curr->sched_class->post_schedule) 1817 rq->curr->sched_class->post_schedule(rq); 1818 raw_spin_unlock_irqrestore(&rq->lock, flags); 1819 1820 rq->post_schedule = 0; 1821 } 1822} 1823 1824#else 1825 1826static inline void pre_schedule(struct rq *rq, struct task_struct *p) 1827{ 1828} 1829 1830static inline void post_schedule(struct rq *rq) 1831{ 1832} 1833 1834#endif 1835 1836/** 1837 * schedule_tail - first thing a freshly forked thread must call. 1838 * @prev: the thread we just switched away from. 1839 */ 1840asmlinkage void schedule_tail(struct task_struct *prev) 1841 __releases(rq->lock) 1842{ 1843 struct rq *rq = this_rq(); 1844 1845 finish_task_switch(rq, prev); 1846 1847 /* 1848 * FIXME: do we need to worry about rq being invalidated by the 1849 * task_switch? 1850 */ 1851 post_schedule(rq); 1852 1853#ifdef __ARCH_WANT_UNLOCKED_CTXSW 1854 /* In this case, finish_task_switch does not reenable preemption */ 1855 preempt_enable(); 1856#endif 1857 if (current->set_child_tid) 1858 put_user(task_pid_vnr(current), current->set_child_tid); 1859} 1860 1861/* 1862 * context_switch - switch to the new MM and the new 1863 * thread's register state. 1864 */ 1865static inline void 1866context_switch(struct rq *rq, struct task_struct *prev, 1867 struct task_struct *next) 1868{ 1869 struct mm_struct *mm, *oldmm; 1870 1871 prepare_task_switch(rq, prev, next); 1872 1873 mm = next->mm; 1874 oldmm = prev->active_mm; 1875 /* 1876 * For paravirt, this is coupled with an exit in switch_to to 1877 * combine the page table reload and the switch backend into 1878 * one hypercall. 1879 */ 1880 arch_start_context_switch(prev); 1881 1882 if (!mm) { 1883 next->active_mm = oldmm; 1884 atomic_inc(&oldmm->mm_count); 1885 enter_lazy_tlb(oldmm, next); 1886 } else 1887 switch_mm(oldmm, mm, next); 1888 1889 if (!prev->mm) { 1890 prev->active_mm = NULL; 1891 rq->prev_mm = oldmm; 1892 } 1893 /* 1894 * Since the runqueue lock will be released by the next 1895 * task (which is an invalid locking op but in the case 1896 * of the scheduler it's an obvious special-case), so we 1897 * do an early lockdep release here: 1898 */ 1899#ifndef __ARCH_WANT_UNLOCKED_CTXSW 1900 spin_release(&rq->lock.dep_map, 1, _THIS_IP_); 1901#endif 1902 1903 /* Here we just switch the register state and the stack. */ 1904 rcu_switch(prev, next); 1905 switch_to(prev, next, prev); 1906 1907 barrier(); 1908 /* 1909 * this_rq must be evaluated again because prev may have moved 1910 * CPUs since it called schedule(), thus the 'rq' on its stack 1911 * frame will be invalid. 1912 */ 1913 finish_task_switch(this_rq(), prev); 1914} 1915 1916/* 1917 * nr_running, nr_uninterruptible and nr_context_switches: 1918 * 1919 * externally visible scheduler statistics: current number of runnable 1920 * threads, current number of uninterruptible-sleeping threads, total 1921 * number of context switches performed since bootup. 1922 */ 1923unsigned long nr_running(void) 1924{ 1925 unsigned long i, sum = 0; 1926 1927 for_each_online_cpu(i) 1928 sum += cpu_rq(i)->nr_running; 1929 1930 return sum; 1931} 1932 1933unsigned long nr_uninterruptible(void) 1934{ 1935 unsigned long i, sum = 0; 1936 1937 for_each_possible_cpu(i) 1938 sum += cpu_rq(i)->nr_uninterruptible; 1939 1940 /* 1941 * Since we read the counters lockless, it might be slightly 1942 * inaccurate. Do not allow it to go below zero though: 1943 */ 1944 if (unlikely((long)sum < 0)) 1945 sum = 0; 1946 1947 return sum; 1948} 1949 1950unsigned long long nr_context_switches(void) 1951{ 1952 int i; 1953 unsigned long long sum = 0; 1954 1955 for_each_possible_cpu(i) 1956 sum += cpu_rq(i)->nr_switches; 1957 1958 return sum; 1959} 1960 1961unsigned long nr_iowait(void) 1962{ 1963 unsigned long i, sum = 0; 1964 1965 for_each_possible_cpu(i) 1966 sum += atomic_read(&cpu_rq(i)->nr_iowait); 1967 1968 return sum; 1969} 1970 1971unsigned long nr_iowait_cpu(int cpu) 1972{ 1973 struct rq *this = cpu_rq(cpu); 1974 return atomic_read(&this->nr_iowait); 1975} 1976 1977unsigned long this_cpu_load(void) 1978{ 1979 struct rq *this = this_rq(); 1980 return this->cpu_load[0]; 1981} 1982 1983 1984/* 1985 * Global load-average calculations 1986 * 1987 * We take a distributed and async approach to calculating the global load-avg 1988 * in order to minimize overhead. 1989 * 1990 * The global load average is an exponentially decaying average of nr_running + 1991 * nr_uninterruptible. 1992 * 1993 * Once every LOAD_FREQ: 1994 * 1995 * nr_active = 0; 1996 * for_each_possible_cpu(cpu) 1997 * nr_active += cpu_of(cpu)->nr_running + cpu_of(cpu)->nr_uninterruptible; 1998 * 1999 * avenrun[n] = avenrun[0] * exp_n + nr_active * (1 - exp_n) 2000 * 2001 * Due to a number of reasons the above turns in the mess below: 2002 * 2003 * - for_each_possible_cpu() is prohibitively expensive on machines with 2004 * serious number of cpus, therefore we need to take a distributed approach 2005 * to calculating nr_active. 2006 * 2007 * \Sum_i x_i(t) = \Sum_i x_i(t) - x_i(t_0) | x_i(t_0) := 0 2008 * = \Sum_i { \Sum_j=1 x_i(t_j) - x_i(t_j-1) } 2009 * 2010 * So assuming nr_active := 0 when we start out -- true per definition, we 2011 * can simply take per-cpu deltas and fold those into a global accumulate 2012 * to obtain the same result. See calc_load_fold_active(). 2013 * 2014 * Furthermore, in order to avoid synchronizing all per-cpu delta folding 2015 * across the machine, we assume 10 ticks is sufficient time for every 2016 * cpu to have completed this task. 2017 * 2018 * This places an upper-bound on the IRQ-off latency of the machine. Then 2019 * again, being late doesn't loose the delta, just wrecks the sample. 2020 * 2021 * - cpu_rq()->nr_uninterruptible isn't accurately tracked per-cpu because 2022 * this would add another cross-cpu cacheline miss and atomic operation 2023 * to the wakeup path. Instead we increment on whatever cpu the task ran 2024 * when it went into uninterruptible state and decrement on whatever cpu 2025 * did the wakeup. This means that only the sum of nr_uninterruptible over 2026 * all cpus yields the correct result. 2027 * 2028 * This covers the NO_HZ=n code, for extra head-aches, see the comment below. 2029 */ 2030 2031/* Variables and functions for calc_load */ 2032static atomic_long_t calc_load_tasks; 2033static unsigned long calc_load_update; 2034unsigned long avenrun[3]; 2035EXPORT_SYMBOL(avenrun); /* should be removed */ 2036 2037/** 2038 * get_avenrun - get the load average array 2039 * @loads: pointer to dest load array 2040 * @offset: offset to add 2041 * @shift: shift count to shift the result left 2042 * 2043 * These values are estimates at best, so no need for locking. 2044 */ 2045void get_avenrun(unsigned long *loads, unsigned long offset, int shift) 2046{ 2047 loads[0] = (avenrun[0] + offset) << shift; 2048 loads[1] = (avenrun[1] + offset) << shift; 2049 loads[2] = (avenrun[2] + offset) << shift; 2050} 2051 2052static long calc_load_fold_active(struct rq *this_rq) 2053{ 2054 long nr_active, delta = 0; 2055 2056 nr_active = this_rq->nr_running; 2057 nr_active += (long) this_rq->nr_uninterruptible; 2058 2059 if (nr_active != this_rq->calc_load_active) { 2060 delta = nr_active - this_rq->calc_load_active; 2061 this_rq->calc_load_active = nr_active; 2062 } 2063 2064 return delta; 2065} 2066 2067/* 2068 * a1 = a0 * e + a * (1 - e) 2069 */ 2070static unsigned long 2071calc_load(unsigned long load, unsigned long exp, unsigned long active) 2072{ 2073 load *= exp; 2074 load += active * (FIXED_1 - exp); 2075 load += 1UL << (FSHIFT - 1); 2076 return load >> FSHIFT; 2077} 2078 2079#ifdef CONFIG_NO_HZ 2080/* 2081 * Handle NO_HZ for the global load-average. 2082 * 2083 * Since the above described distributed algorithm to compute the global 2084 * load-average relies on per-cpu sampling from the tick, it is affected by 2085 * NO_HZ. 2086 * 2087 * The basic idea is to fold the nr_active delta into a global idle-delta upon 2088 * entering NO_HZ state such that we can include this as an 'extra' cpu delta 2089 * when we read the global state. 2090 * 2091 * Obviously reality has to ruin such a delightfully simple scheme: 2092 * 2093 * - When we go NO_HZ idle during the window, we can negate our sample 2094 * contribution, causing under-accounting. 2095 * 2096 * We avoid this by keeping two idle-delta counters and flipping them 2097 * when the window starts, thus separating old and new NO_HZ load. 2098 * 2099 * The only trick is the slight shift in index flip for read vs write. 2100 * 2101 * 0s 5s 10s 15s 2102 * +10 +10 +10 +10 2103 * |-|-----------|-|-----------|-|-----------|-| 2104 * r:0 0 1 1 0 0 1 1 0 2105 * w:0 1 1 0 0 1 1 0 0 2106 * 2107 * This ensures we'll fold the old idle contribution in this window while 2108 * accumlating the new one. 2109 * 2110 * - When we wake up from NO_HZ idle during the window, we push up our 2111 * contribution, since we effectively move our sample point to a known 2112 * busy state. 2113 * 2114 * This is solved by pushing the window forward, and thus skipping the 2115 * sample, for this cpu (effectively using the idle-delta for this cpu which 2116 * was in effect at the time the window opened). This also solves the issue 2117 * of having to deal with a cpu having been in NOHZ idle for multiple 2118 * LOAD_FREQ intervals. 2119 * 2120 * When making the ILB scale, we should try to pull this in as well. 2121 */ 2122static atomic_long_t calc_load_idle[2]; 2123static int calc_load_idx; 2124 2125static inline int calc_load_write_idx(void) 2126{ 2127 int idx = calc_load_idx; 2128 2129 /* 2130 * See calc_global_nohz(), if we observe the new index, we also 2131 * need to observe the new update time. 2132 */ 2133 smp_rmb(); 2134 2135 /* 2136 * If the folding window started, make sure we start writing in the 2137 * next idle-delta. 2138 */ 2139 if (!time_before(jiffies, calc_load_update)) 2140 idx++; 2141 2142 return idx & 1; 2143} 2144 2145static inline int calc_load_read_idx(void) 2146{ 2147 return calc_load_idx & 1; 2148} 2149 2150void calc_load_enter_idle(void) 2151{ 2152 struct rq *this_rq = this_rq(); 2153 long delta; 2154 2155 /* 2156 * We're going into NOHZ mode, if there's any pending delta, fold it 2157 * into the pending idle delta. 2158 */ 2159 delta = calc_load_fold_active(this_rq); 2160 if (delta) { 2161 int idx = calc_load_write_idx(); 2162 atomic_long_add(delta, &calc_load_idle[idx]); 2163 } 2164} 2165 2166void calc_load_exit_idle(void) 2167{ 2168 struct rq *this_rq = this_rq(); 2169 2170 /* 2171 * If we're still before the sample window, we're done. 2172 */ 2173 if (time_before(jiffies, this_rq->calc_load_update)) 2174 return; 2175 2176 /* 2177 * We woke inside or after the sample window, this means we're already 2178 * accounted through the nohz accounting, so skip the entire deal and 2179 * sync up for the next window. 2180 */ 2181 this_rq->calc_load_update = calc_load_update; 2182 if (time_before(jiffies, this_rq->calc_load_update + 10)) 2183 this_rq->calc_load_update += LOAD_FREQ; 2184} 2185 2186static long calc_load_fold_idle(void) 2187{ 2188 int idx = calc_load_read_idx(); 2189 long delta = 0; 2190 2191 if (atomic_long_read(&calc_load_idle[idx])) 2192 delta = atomic_long_xchg(&calc_load_idle[idx], 0); 2193 2194 return delta; 2195} 2196 2197/** 2198 * fixed_power_int - compute: x^n, in O(log n) time 2199 * 2200 * @x: base of the power 2201 * @frac_bits: fractional bits of @x 2202 * @n: power to raise @x to. 2203 * 2204 * By exploiting the relation between the definition of the natural power 2205 * function: x^n := x*x*...*x (x multiplied by itself for n times), and 2206 * the binary encoding of numbers used by computers: n := \Sum n_i * 2^i, 2207 * (where: n_i \elem {0, 1}, the binary vector representing n), 2208 * we find: x^n := x^(\Sum n_i * 2^i) := \Prod x^(n_i * 2^i), which is 2209 * of course trivially computable in O(log_2 n), the length of our binary 2210 * vector. 2211 */ 2212static unsigned long 2213fixed_power_int(unsigned long x, unsigned int frac_bits, unsigned int n) 2214{ 2215 unsigned long result = 1UL << frac_bits; 2216 2217 if (n) for (;;) { 2218 if (n & 1) { 2219 result *= x; 2220 result += 1UL << (frac_bits - 1); 2221 result >>= frac_bits; 2222 } 2223 n >>= 1; 2224 if (!n) 2225 break; 2226 x *= x; 2227 x += 1UL << (frac_bits - 1); 2228 x >>= frac_bits; 2229 } 2230 2231 return result; 2232} 2233 2234/* 2235 * a1 = a0 * e + a * (1 - e) 2236 * 2237 * a2 = a1 * e + a * (1 - e) 2238 * = (a0 * e + a * (1 - e)) * e + a * (1 - e) 2239 * = a0 * e^2 + a * (1 - e) * (1 + e) 2240 * 2241 * a3 = a2 * e + a * (1 - e) 2242 * = (a0 * e^2 + a * (1 - e) * (1 + e)) * e + a * (1 - e) 2243 * = a0 * e^3 + a * (1 - e) * (1 + e + e^2) 2244 * 2245 * ... 2246 * 2247 * an = a0 * e^n + a * (1 - e) * (1 + e + ... + e^n-1) [1] 2248 * = a0 * e^n + a * (1 - e) * (1 - e^n)/(1 - e) 2249 * = a0 * e^n + a * (1 - e^n) 2250 * 2251 * [1] application of the geometric series: 2252 * 2253 * n 1 - x^(n+1) 2254 * S_n := \Sum x^i = ------------- 2255 * i=0 1 - x 2256 */ 2257static unsigned long 2258calc_load_n(unsigned long load, unsigned long exp, 2259 unsigned long active, unsigned int n) 2260{ 2261 2262 return calc_load(load, fixed_power_int(exp, FSHIFT, n), active); 2263} 2264 2265/* 2266 * NO_HZ can leave us missing all per-cpu ticks calling 2267 * calc_load_account_active(), but since an idle CPU folds its delta into 2268 * calc_load_tasks_idle per calc_load_account_idle(), all we need to do is fold 2269 * in the pending idle delta if our idle period crossed a load cycle boundary. 2270 * 2271 * Once we've updated the global active value, we need to apply the exponential 2272 * weights adjusted to the number of cycles missed. 2273 */ 2274static void calc_global_nohz(void) 2275{ 2276 long delta, active, n; 2277 2278 if (!time_before(jiffies, calc_load_update + 10)) { 2279 /* 2280 * Catch-up, fold however many we are behind still 2281 */ 2282 delta = jiffies - calc_load_update - 10; 2283 n = 1 + (delta / LOAD_FREQ); 2284 2285 active = atomic_long_read(&calc_load_tasks); 2286 active = active > 0 ? active * FIXED_1 : 0; 2287 2288 avenrun[0] = calc_load_n(avenrun[0], EXP_1, active, n); 2289 avenrun[1] = calc_load_n(avenrun[1], EXP_5, active, n); 2290 avenrun[2] = calc_load_n(avenrun[2], EXP_15, active, n); 2291 2292 calc_load_update += n * LOAD_FREQ; 2293 } 2294 2295 /* 2296 * Flip the idle index... 2297 * 2298 * Make sure we first write the new time then flip the index, so that 2299 * calc_load_write_idx() will see the new time when it reads the new 2300 * index, this avoids a double flip messing things up. 2301 */ 2302 smp_wmb(); 2303 calc_load_idx++; 2304} 2305#else /* !CONFIG_NO_HZ */ 2306 2307static inline long calc_load_fold_idle(void) { return 0; } 2308static inline void calc_global_nohz(void) { } 2309 2310#endif /* CONFIG_NO_HZ */ 2311 2312/* 2313 * calc_load - update the avenrun load estimates 10 ticks after the 2314 * CPUs have updated calc_load_tasks. 2315 */ 2316void calc_global_load(unsigned long ticks) 2317{ 2318 long active, delta; 2319 2320 if (time_before(jiffies, calc_load_update + 10)) 2321 return; 2322 2323 /* 2324 * Fold the 'old' idle-delta to include all NO_HZ cpus. 2325 */ 2326 delta = calc_load_fold_idle(); 2327 if (delta) 2328 atomic_long_add(delta, &calc_load_tasks); 2329 2330 active = atomic_long_read(&calc_load_tasks); 2331 active = active > 0 ? active * FIXED_1 : 0; 2332 2333 avenrun[0] = calc_load(avenrun[0], EXP_1, active); 2334 avenrun[1] = calc_load(avenrun[1], EXP_5, active); 2335 avenrun[2] = calc_load(avenrun[2], EXP_15, active); 2336 2337 calc_load_update += LOAD_FREQ; 2338 2339 /* 2340 * In case we idled for multiple LOAD_FREQ intervals, catch up in bulk. 2341 */ 2342 calc_global_nohz(); 2343} 2344 2345/* 2346 * Called from update_cpu_load() to periodically update this CPU's 2347 * active count. 2348 */ 2349static void calc_load_account_active(struct rq *this_rq) 2350{ 2351 long delta; 2352 2353 if (time_before(jiffies, this_rq->calc_load_update)) 2354 return; 2355 2356 delta = calc_load_fold_active(this_rq); 2357 if (delta) 2358 atomic_long_add(delta, &calc_load_tasks); 2359 2360 this_rq->calc_load_update += LOAD_FREQ; 2361} 2362 2363/* 2364 * End of global load-average stuff 2365 */ 2366 2367/* 2368 * The exact cpuload at various idx values, calculated at every tick would be 2369 * load = (2^idx - 1) / 2^idx * load + 1 / 2^idx * cur_load 2370 * 2371 * If a cpu misses updates for n-1 ticks (as it was idle) and update gets called 2372 * on nth tick when cpu may be busy, then we have: 2373 * load = ((2^idx - 1) / 2^idx)^(n-1) * load 2374 * load = (2^idx - 1) / 2^idx) * load + 1 / 2^idx * cur_load 2375 * 2376 * decay_load_missed() below does efficient calculation of 2377 * load = ((2^idx - 1) / 2^idx)^(n-1) * load 2378 * avoiding 0..n-1 loop doing load = ((2^idx - 1) / 2^idx) * load 2379 * 2380 * The calculation is approximated on a 128 point scale. 2381 * degrade_zero_ticks is the number of ticks after which load at any 2382 * particular idx is approximated to be zero. 2383 * degrade_factor is a precomputed table, a row for each load idx. 2384 * Each column corresponds to degradation factor for a power of two ticks, 2385 * based on 128 point scale. 2386 * Example: 2387 * row 2, col 3 (=12) says that the degradation at load idx 2 after 2388 * 8 ticks is 12/128 (which is an approximation of exact factor 3^8/4^8). 2389 * 2390 * With this power of 2 load factors, we can degrade the load n times 2391 * by looking at 1 bits in n and doing as many mult/shift instead of 2392 * n mult/shifts needed by the exact degradation. 2393 */ 2394#define DEGRADE_SHIFT 7 2395static const unsigned char 2396 degrade_zero_ticks[CPU_LOAD_IDX_MAX] = {0, 8, 32, 64, 128}; 2397static const unsigned char 2398 degrade_factor[CPU_LOAD_IDX_MAX][DEGRADE_SHIFT + 1] = { 2399 {0, 0, 0, 0, 0, 0, 0, 0}, 2400 {64, 32, 8, 0, 0, 0, 0, 0}, 2401 {96, 72, 40, 12, 1, 0, 0}, 2402 {112, 98, 75, 43, 15, 1, 0}, 2403 {120, 112, 98, 76, 45, 16, 2} }; 2404 2405/* 2406 * Update cpu_load for any missed ticks, due to tickless idle. The backlog 2407 * would be when CPU is idle and so we just decay the old load without 2408 * adding any new load. 2409 */ 2410static unsigned long 2411decay_load_missed(unsigned long load, unsigned long missed_updates, int idx) 2412{ 2413 int j = 0; 2414 2415 if (!missed_updates) 2416 return load; 2417 2418 if (missed_updates >= degrade_zero_ticks[idx]) 2419 return 0; 2420 2421 if (idx == 1) 2422 return load >> missed_updates; 2423 2424 while (missed_updates) { 2425 if (missed_updates % 2) 2426 load = (load * degrade_factor[idx][j]) >> DEGRADE_SHIFT; 2427 2428 missed_updates >>= 1; 2429 j++; 2430 } 2431 return load; 2432} 2433 2434/* 2435 * Update rq->cpu_load[] statistics. This function is usually called every 2436 * scheduler tick (TICK_NSEC). With tickless idle this will not be called 2437 * every tick. We fix it up based on jiffies. 2438 */ 2439static void __update_cpu_load(struct rq *this_rq, unsigned long this_load, 2440 unsigned long pending_updates) 2441{ 2442 int i, scale; 2443 2444 this_rq->nr_load_updates++; 2445 2446 /* Update our load: */ 2447 this_rq->cpu_load[0] = this_load; /* Fasttrack for idx 0 */ 2448 for (i = 1, scale = 2; i < CPU_LOAD_IDX_MAX; i++, scale += scale) { 2449 unsigned long old_load, new_load; 2450 2451 /* scale is effectively 1 << i now, and >> i divides by scale */ 2452 2453 old_load = this_rq->cpu_load[i]; 2454 old_load = decay_load_missed(old_load, pending_updates - 1, i); 2455 new_load = this_load; 2456 /* 2457 * Round up the averaging division if load is increasing. This 2458 * prevents us from getting stuck on 9 if the load is 10, for 2459 * example. 2460 */ 2461 if (new_load > old_load) 2462 new_load += scale - 1; 2463 2464 this_rq->cpu_load[i] = (old_load * (scale - 1) + new_load) >> i; 2465 } 2466 2467 sched_avg_update(this_rq); 2468} 2469 2470#ifdef CONFIG_NO_HZ 2471/* 2472 * There is no sane way to deal with nohz on smp when using jiffies because the 2473 * cpu doing the jiffies update might drift wrt the cpu doing the jiffy reading 2474 * causing off-by-one errors in observed deltas; {0,2} instead of {1,1}. 2475 * 2476 * Therefore we cannot use the delta approach from the regular tick since that 2477 * would seriously skew the load calculation. However we'll make do for those 2478 * updates happening while idle (nohz_idle_balance) or coming out of idle 2479 * (tick_nohz_idle_exit). 2480 * 2481 * This means we might still be one tick off for nohz periods. 2482 */ 2483 2484/* 2485 * Called from nohz_idle_balance() to update the load ratings before doing the 2486 * idle balance. 2487 */ 2488void update_idle_cpu_load(struct rq *this_rq) 2489{ 2490 unsigned long curr_jiffies = ACCESS_ONCE(jiffies); 2491 unsigned long load = this_rq->load.weight; 2492 unsigned long pending_updates; 2493 2494 /* 2495 * bail if there's load or we're actually up-to-date. 2496 */ 2497 if (load || curr_jiffies == this_rq->last_load_update_tick) 2498 return; 2499 2500 pending_updates = curr_jiffies - this_rq->last_load_update_tick; 2501 this_rq->last_load_update_tick = curr_jiffies; 2502 2503 __update_cpu_load(this_rq, load, pending_updates); 2504} 2505 2506/* 2507 * Called from tick_nohz_idle_exit() -- try and fix up the ticks we missed. 2508 */ 2509void update_cpu_load_nohz(void) 2510{ 2511 struct rq *this_rq = this_rq(); 2512 unsigned long curr_jiffies = ACCESS_ONCE(jiffies); 2513 unsigned long pending_updates; 2514 2515 if (curr_jiffies == this_rq->last_load_update_tick) 2516 return; 2517 2518 raw_spin_lock(&this_rq->lock); 2519 pending_updates = curr_jiffies - this_rq->last_load_update_tick; 2520 if (pending_updates) { 2521 this_rq->last_load_update_tick = curr_jiffies; 2522 /* 2523 * We were idle, this means load 0, the current load might be 2524 * !0 due to remote wakeups and the sort. 2525 */ 2526 __update_cpu_load(this_rq, 0, pending_updates); 2527 } 2528 raw_spin_unlock(&this_rq->lock); 2529} 2530#endif /* CONFIG_NO_HZ */ 2531 2532/* 2533 * Called from scheduler_tick() 2534 */ 2535static void update_cpu_load_active(struct rq *this_rq) 2536{ 2537 /* 2538 * See the mess around update_idle_cpu_load() / update_cpu_load_nohz(). 2539 */ 2540 this_rq->last_load_update_tick = jiffies; 2541 __update_cpu_load(this_rq, this_rq->load.weight, 1); 2542 2543 calc_load_account_active(this_rq); 2544} 2545 2546#ifdef CONFIG_SMP 2547 2548/* 2549 * sched_exec - execve() is a valuable balancing opportunity, because at 2550 * this point the task has the smallest effective memory and cache footprint. 2551 */ 2552void sched_exec(void) 2553{ 2554 struct task_struct *p = current; 2555 unsigned long flags; 2556 int dest_cpu; 2557 2558 raw_spin_lock_irqsave(&p->pi_lock, flags); 2559 dest_cpu = p->sched_class->select_task_rq(p, SD_BALANCE_EXEC, 0); 2560 if (dest_cpu == smp_processor_id()) 2561 goto unlock; 2562 2563 if (likely(cpu_active(dest_cpu))) { 2564 struct migration_arg arg = { p, dest_cpu }; 2565 2566 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 2567 stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg); 2568 return; 2569 } 2570unlock: 2571 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 2572} 2573 2574#endif 2575 2576DEFINE_PER_CPU(struct kernel_stat, kstat); 2577DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat); 2578 2579EXPORT_PER_CPU_SYMBOL(kstat); 2580EXPORT_PER_CPU_SYMBOL(kernel_cpustat); 2581 2582/* 2583 * Return any ns on the sched_clock that have not yet been accounted in 2584 * @p in case that task is currently running. 2585 * 2586 * Called with task_rq_lock() held on @rq. 2587 */ 2588static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq) 2589{ 2590 u64 ns = 0; 2591 2592 if (task_current(rq, p)) { 2593 update_rq_clock(rq); 2594 ns = rq->clock_task - p->se.exec_start; 2595 if ((s64)ns < 0) 2596 ns = 0; 2597 } 2598 2599 return ns; 2600} 2601 2602unsigned long long task_delta_exec(struct task_struct *p) 2603{ 2604 unsigned long flags; 2605 struct rq *rq; 2606 u64 ns = 0; 2607 2608 rq = task_rq_lock(p, &flags); 2609 ns = do_task_delta_exec(p, rq); 2610 task_rq_unlock(rq, p, &flags); 2611 2612 return ns; 2613} 2614 2615/* 2616 * Return accounted runtime for the task. 2617 * In case the task is currently running, return the runtime plus current's 2618 * pending runtime that have not been accounted yet. 2619 */ 2620unsigned long long task_sched_runtime(struct task_struct *p) 2621{ 2622 unsigned long flags; 2623 struct rq *rq; 2624 u64 ns = 0; 2625 2626 rq = task_rq_lock(p, &flags); 2627 ns = p->se.sum_exec_runtime + do_task_delta_exec(p, rq); 2628 task_rq_unlock(rq, p, &flags); 2629 2630 return ns; 2631} 2632 2633/* 2634 * This function gets called by the timer code, with HZ frequency. 2635 * We call it with interrupts disabled. 2636 */ 2637void scheduler_tick(void) 2638{ 2639 int cpu = smp_processor_id(); 2640 struct rq *rq = cpu_rq(cpu); 2641 struct task_struct *curr = rq->curr; 2642 2643 sched_clock_tick(); 2644 2645 raw_spin_lock(&rq->lock); 2646 update_rq_clock(rq); 2647 update_cpu_load_active(rq); 2648 curr->sched_class->task_tick(rq, curr, 0); 2649 raw_spin_unlock(&rq->lock); 2650 2651 perf_event_task_tick(); 2652 2653#ifdef CONFIG_SMP 2654 rq->idle_balance = idle_cpu(cpu); 2655 trigger_load_balance(rq, cpu); 2656#endif 2657} 2658 2659notrace unsigned long get_parent_ip(unsigned long addr) 2660{ 2661 if (in_lock_functions(addr)) { 2662 addr = CALLER_ADDR2; 2663 if (in_lock_functions(addr)) 2664 addr = CALLER_ADDR3; 2665 } 2666 return addr; 2667} 2668 2669#if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \ 2670 defined(CONFIG_PREEMPT_TRACER)) 2671 2672void __kprobes add_preempt_count(int val) 2673{ 2674#ifdef CONFIG_DEBUG_PREEMPT 2675 /* 2676 * Underflow? 2677 */ 2678 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) 2679 return; 2680#endif 2681 preempt_count() += val; 2682#ifdef CONFIG_DEBUG_PREEMPT 2683 /* 2684 * Spinlock count overflowing soon? 2685 */ 2686 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= 2687 PREEMPT_MASK - 10); 2688#endif 2689 if (preempt_count() == val) 2690 trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); 2691} 2692EXPORT_SYMBOL(add_preempt_count); 2693 2694void __kprobes sub_preempt_count(int val) 2695{ 2696#ifdef CONFIG_DEBUG_PREEMPT 2697 /* 2698 * Underflow? 2699 */ 2700 if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) 2701 return; 2702 /* 2703 * Is the spinlock portion underflowing? 2704 */ 2705 if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && 2706 !(preempt_count() & PREEMPT_MASK))) 2707 return; 2708#endif 2709 2710 if (preempt_count() == val) 2711 trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); 2712 preempt_count() -= val; 2713} 2714EXPORT_SYMBOL(sub_preempt_count); 2715 2716#endif 2717 2718/* 2719 * Print scheduling while atomic bug: 2720 */ 2721static noinline void __schedule_bug(struct task_struct *prev) 2722{ 2723 if (oops_in_progress) 2724 return; 2725 2726 printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n", 2727 prev->comm, prev->pid, preempt_count()); 2728 2729 debug_show_held_locks(prev); 2730 print_modules(); 2731 if (irqs_disabled()) 2732 print_irqtrace_events(prev); 2733 dump_stack(); 2734 add_taint(TAINT_WARN); 2735} 2736 2737/* 2738 * Various schedule()-time debugging checks and statistics: 2739 */ 2740static inline void schedule_debug(struct task_struct *prev) 2741{ 2742 /* 2743 * Test if we are atomic. Since do_exit() needs to call into 2744 * schedule() atomically, we ignore that path for now. 2745 * Otherwise, whine if we are scheduling when we should not be. 2746 */ 2747 if (unlikely(in_atomic_preempt_off() && !prev->exit_state)) 2748 __schedule_bug(prev); 2749 rcu_sleep_check(); 2750 2751 profile_hit(SCHED_PROFILING, __builtin_return_address(0)); 2752 2753 schedstat_inc(this_rq(), sched_count); 2754} 2755 2756static void put_prev_task(struct rq *rq, struct task_struct *prev) 2757{ 2758 if (prev->on_rq || rq->skip_clock_update < 0) 2759 update_rq_clock(rq); 2760 prev->sched_class->put_prev_task(rq, prev); 2761} 2762 2763/* 2764 * Pick up the highest-prio task: 2765 */ 2766static inline struct task_struct * 2767pick_next_task(struct rq *rq) 2768{ 2769 const struct sched_class *class; 2770 struct task_struct *p; 2771 2772 /* 2773 * Optimization: we know that if all tasks are in 2774 * the fair class we can call that function directly: 2775 */ 2776 if (likely(rq->nr_running == rq->cfs.h_nr_running)) { 2777 p = fair_sched_class.pick_next_task(rq); 2778 if (likely(p)) 2779 return p; 2780 } 2781 2782 for_each_class(class) { 2783 p = class->pick_next_task(rq); 2784 if (p) 2785 return p; 2786 } 2787 2788 BUG(); /* the idle class will always have a runnable task */ 2789} 2790 2791/* 2792 * __schedule() is the main scheduler function. 2793 * 2794 * The main means of driving the scheduler and thus entering this function are: 2795 * 2796 * 1. Explicit blocking: mutex, semaphore, waitqueue, etc. 2797 * 2798 * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return 2799 * paths. For example, see arch/x86/entry_64.S. 2800 * 2801 * To drive preemption between tasks, the scheduler sets the flag in timer 2802 * interrupt handler scheduler_tick(). 2803 * 2804 * 3. Wakeups don't really cause entry into schedule(). They add a 2805 * task to the run-queue and that's it. 2806 * 2807 * Now, if the new task added to the run-queue preempts the current 2808 * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets 2809 * called on the nearest possible occasion: 2810 * 2811 * - If the kernel is preemptible (CONFIG_PREEMPT=y): 2812 * 2813 * - in syscall or exception context, at the next outmost 2814 * preempt_enable(). (this might be as soon as the wake_up()'s 2815 * spin_unlock()!) 2816 * 2817 * - in IRQ context, return from interrupt-handler to 2818 * preemptible context 2819 * 2820 * - If the kernel is not preemptible (CONFIG_PREEMPT is not set) 2821 * then at the next: 2822 * 2823 * - cond_resched() call 2824 * - explicit schedule() call 2825 * - return from syscall or exception to user-space 2826 * - return from interrupt-handler to user-space 2827 */ 2828static void __sched __schedule(void) 2829{ 2830 struct task_struct *prev, *next; 2831 unsigned long *switch_count; 2832 struct rq *rq; 2833 int cpu; 2834 2835need_resched: 2836 preempt_disable(); 2837 cpu = smp_processor_id(); 2838 rq = cpu_rq(cpu); 2839 rcu_note_context_switch(cpu); 2840 prev = rq->curr; 2841 2842 schedule_debug(prev); 2843 2844 if (sched_feat(HRTICK)) 2845 hrtick_clear(rq); 2846 2847 raw_spin_lock_irq(&rq->lock); 2848 2849 switch_count = &prev->nivcsw; 2850 if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { 2851 if (unlikely(signal_pending_state(prev->state, prev))) { 2852 prev->state = TASK_RUNNING; 2853 } else { 2854 deactivate_task(rq, prev, DEQUEUE_SLEEP); 2855 prev->on_rq = 0; 2856 2857 /* 2858 * If a worker went to sleep, notify and ask workqueue 2859 * whether it wants to wake up a task to maintain 2860 * concurrency. 2861 */ 2862 if (prev->flags & PF_WQ_WORKER) { 2863 struct task_struct *to_wakeup; 2864 2865 to_wakeup = wq_worker_sleeping(prev, cpu); 2866 if (to_wakeup) 2867 try_to_wake_up_local(to_wakeup); 2868 } 2869 } 2870 switch_count = &prev->nvcsw; 2871 } 2872 2873 pre_schedule(rq, prev); 2874 2875 if (unlikely(!rq->nr_running)) 2876 idle_balance(cpu, rq); 2877 2878 put_prev_task(rq, prev); 2879 next = pick_next_task(rq); 2880 clear_tsk_need_resched(prev); 2881 rq->skip_clock_update = 0; 2882 2883 if (likely(prev != next)) { 2884 rq->nr_switches++; 2885 rq->curr = next; 2886 ++*switch_count; 2887 2888 context_switch(rq, prev, next); /* unlocks the rq */ 2889 /* 2890 * The context switch have flipped the stack from under us 2891 * and restored the local variables which were saved when 2892 * this task called schedule() in the past. prev == current 2893 * is still correct, but it can be moved to another cpu/rq. 2894 */ 2895 cpu = smp_processor_id(); 2896 rq = cpu_rq(cpu); 2897 } else 2898 raw_spin_unlock_irq(&rq->lock); 2899 2900 post_schedule(rq); 2901 2902 sched_preempt_enable_no_resched(); 2903 if (need_resched()) 2904 goto need_resched; 2905} 2906 2907static inline void sched_submit_work(struct task_struct *tsk) 2908{ 2909 if (!tsk->state || tsk_is_pi_blocked(tsk)) 2910 return; 2911 /* 2912 * If we are going to sleep and we have plugged IO queued, 2913 * make sure to submit it to avoid deadlocks. 2914 */ 2915 if (blk_needs_flush_plug(tsk)) 2916 blk_schedule_flush_plug(tsk); 2917} 2918 2919asmlinkage void __sched schedule(void) 2920{ 2921 struct task_struct *tsk = current; 2922 2923 sched_submit_work(tsk); 2924 __schedule(); 2925} 2926EXPORT_SYMBOL(schedule); 2927 2928#ifdef CONFIG_RCU_USER_QS 2929asmlinkage void __sched schedule_user(void) 2930{ 2931 /* 2932 * If we come here after a random call to set_need_resched(), 2933 * or we have been woken up remotely but the IPI has not yet arrived, 2934 * we haven't yet exited the RCU idle mode. Do it here manually until 2935 * we find a better solution. 2936 */ 2937 rcu_user_exit(); 2938 schedule(); 2939 rcu_user_enter(); 2940} 2941#endif 2942 2943/** 2944 * schedule_preempt_disabled - called with preemption disabled 2945 * 2946 * Returns with preemption disabled. Note: preempt_count must be 1 2947 */ 2948void __sched schedule_preempt_disabled(void) 2949{ 2950 sched_preempt_enable_no_resched(); 2951 schedule(); 2952 preempt_disable(); 2953} 2954 2955#ifdef CONFIG_MUTEX_SPIN_ON_OWNER 2956 2957static inline bool owner_running(struct mutex *lock, struct task_struct *owner) 2958{ 2959 if (lock->owner != owner) 2960 return false; 2961 2962 /* 2963 * Ensure we emit the owner->on_cpu, dereference _after_ checking 2964 * lock->owner still matches owner, if that fails, owner might 2965 * point to free()d memory, if it still matches, the rcu_read_lock() 2966 * ensures the memory stays valid. 2967 */ 2968 barrier(); 2969 2970 return owner->on_cpu; 2971} 2972 2973/* 2974 * Look out! "owner" is an entirely speculative pointer 2975 * access and not reliable. 2976 */ 2977int mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner) 2978{ 2979 if (!sched_feat(OWNER_SPIN)) 2980 return 0; 2981 2982 rcu_read_lock(); 2983 while (owner_running(lock, owner)) { 2984 if (need_resched()) 2985 break; 2986 2987 arch_mutex_cpu_relax(); 2988 } 2989 rcu_read_unlock(); 2990 2991 /* 2992 * We break out the loop above on need_resched() and when the 2993 * owner changed, which is a sign for heavy contention. Return 2994 * success only when lock->owner is NULL. 2995 */ 2996 return lock->owner == NULL; 2997} 2998#endif 2999 3000#ifdef CONFIG_PREEMPT 3001/* 3002 * this is the entry point to schedule() from in-kernel preemption 3003 * off of preempt_enable. Kernel preemptions off return from interrupt 3004 * occur there and call schedule directly. 3005 */ 3006asmlinkage void __sched notrace preempt_schedule(void) 3007{ 3008 struct thread_info *ti = current_thread_info(); 3009 3010 /* 3011 * If there is a non-zero preempt_count or interrupts are disabled, 3012 * we do not want to preempt the current task. Just return.. 3013 */ 3014 if (likely(ti->preempt_count || irqs_disabled())) 3015 return; 3016 3017 do { 3018 add_preempt_count_notrace(PREEMPT_ACTIVE); 3019 __schedule(); 3020 sub_preempt_count_notrace(PREEMPT_ACTIVE); 3021 3022 /* 3023 * Check again in case we missed a preemption opportunity 3024 * between schedule and now. 3025 */ 3026 barrier(); 3027 } while (need_resched()); 3028} 3029EXPORT_SYMBOL(preempt_schedule); 3030 3031/* 3032 * this is the entry point to schedule() from kernel preemption 3033 * off of irq context. 3034 * Note, that this is called and return with irqs disabled. This will 3035 * protect us against recursive calling from irq. 3036 */ 3037asmlinkage void __sched preempt_schedule_irq(void) 3038{ 3039 struct thread_info *ti = current_thread_info(); 3040 3041 /* Catch callers which need to be fixed */ 3042 BUG_ON(ti->preempt_count || !irqs_disabled()); 3043 3044 rcu_user_exit(); 3045 do { 3046 add_preempt_count(PREEMPT_ACTIVE); 3047 local_irq_enable(); 3048 __schedule(); 3049 local_irq_disable(); 3050 sub_preempt_count(PREEMPT_ACTIVE); 3051 3052 /* 3053 * Check again in case we missed a preemption opportunity 3054 * between schedule and now. 3055 */ 3056 barrier(); 3057 } while (need_resched()); 3058} 3059 3060#endif /* CONFIG_PREEMPT */ 3061 3062int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags, 3063 void *key) 3064{ 3065 return try_to_wake_up(curr->private, mode, wake_flags); 3066} 3067EXPORT_SYMBOL(default_wake_function); 3068 3069/* 3070 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just 3071 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve 3072 * number) then we wake all the non-exclusive tasks and one exclusive task. 3073 * 3074 * There are circumstances in which we can try to wake a task which has already 3075 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns 3076 * zero in this (rare) case, and we handle it by continuing to scan the queue. 3077 */ 3078static void __wake_up_common(wait_queue_head_t *q, unsigned int mode, 3079 int nr_exclusive, int wake_flags, void *key) 3080{ 3081 wait_queue_t *curr, *next; 3082 3083 list_for_each_entry_safe(curr, next, &q->task_list, task_list) { 3084 unsigned flags = curr->flags; 3085 3086 if (curr->func(curr, mode, wake_flags, key) && 3087 (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive) 3088 break; 3089 } 3090} 3091 3092/** 3093 * __wake_up - wake up threads blocked on a waitqueue. 3094 * @q: the waitqueue 3095 * @mode: which threads 3096 * @nr_exclusive: how many wake-one or wake-many threads to wake up 3097 * @key: is directly passed to the wakeup function 3098 * 3099 * It may be assumed that this function implies a write memory barrier before 3100 * changing the task state if and only if any tasks are woken up. 3101 */ 3102void __wake_up(wait_queue_head_t *q, unsigned int mode, 3103 int nr_exclusive, void *key) 3104{ 3105 unsigned long flags; 3106 3107 spin_lock_irqsave(&q->lock, flags); 3108 __wake_up_common(q, mode, nr_exclusive, 0, key); 3109 spin_unlock_irqrestore(&q->lock, flags); 3110} 3111EXPORT_SYMBOL(__wake_up); 3112 3113/* 3114 * Same as __wake_up but called with the spinlock in wait_queue_head_t held. 3115 */ 3116void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr) 3117{ 3118 __wake_up_common(q, mode, nr, 0, NULL); 3119} 3120EXPORT_SYMBOL_GPL(__wake_up_locked); 3121 3122void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key) 3123{ 3124 __wake_up_common(q, mode, 1, 0, key); 3125} 3126EXPORT_SYMBOL_GPL(__wake_up_locked_key); 3127 3128/** 3129 * __wake_up_sync_key - wake up threads blocked on a waitqueue. 3130 * @q: the waitqueue 3131 * @mode: which threads 3132 * @nr_exclusive: how many wake-one or wake-many threads to wake up 3133 * @key: opaque value to be passed to wakeup targets 3134 * 3135 * The sync wakeup differs that the waker knows that it will schedule 3136 * away soon, so while the target thread will be woken up, it will not 3137 * be migrated to another CPU - ie. the two threads are 'synchronized' 3138 * with each other. This can prevent needless bouncing between CPUs. 3139 * 3140 * On UP it can prevent extra preemption. 3141 * 3142 * It may be assumed that this function implies a write memory barrier before 3143 * changing the task state if and only if any tasks are woken up. 3144 */ 3145void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, 3146 int nr_exclusive, void *key) 3147{ 3148 unsigned long flags; 3149 int wake_flags = WF_SYNC; 3150 3151 if (unlikely(!q)) 3152 return; 3153 3154 if (unlikely(!nr_exclusive)) 3155 wake_flags = 0; 3156 3157 spin_lock_irqsave(&q->lock, flags); 3158 __wake_up_common(q, mode, nr_exclusive, wake_flags, key); 3159 spin_unlock_irqrestore(&q->lock, flags); 3160} 3161EXPORT_SYMBOL_GPL(__wake_up_sync_key); 3162 3163/* 3164 * __wake_up_sync - see __wake_up_sync_key() 3165 */ 3166void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive) 3167{ 3168 __wake_up_sync_key(q, mode, nr_exclusive, NULL); 3169} 3170EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */ 3171 3172/** 3173 * complete: - signals a single thread waiting on this completion 3174 * @x: holds the state of this particular completion 3175 * 3176 * This will wake up a single thread waiting on this completion. Threads will be 3177 * awakened in the same order in which they were queued. 3178 * 3179 * See also complete_all(), wait_for_completion() and related routines. 3180 * 3181 * It may be assumed that this function implies a write memory barrier before 3182 * changing the task state if and only if any tasks are woken up. 3183 */ 3184void complete(struct completion *x) 3185{ 3186 unsigned long flags; 3187 3188 spin_lock_irqsave(&x->wait.lock, flags); 3189 x->done++; 3190 __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL); 3191 spin_unlock_irqrestore(&x->wait.lock, flags); 3192} 3193EXPORT_SYMBOL(complete); 3194 3195/** 3196 * complete_all: - signals all threads waiting on this completion 3197 * @x: holds the state of this particular completion 3198 * 3199 * This will wake up all threads waiting on this particular completion event. 3200 * 3201 * It may be assumed that this function implies a write memory barrier before 3202 * changing the task state if and only if any tasks are woken up. 3203 */ 3204void complete_all(struct completion *x) 3205{ 3206 unsigned long flags; 3207 3208 spin_lock_irqsave(&x->wait.lock, flags); 3209 x->done += UINT_MAX/2; 3210 __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL); 3211 spin_unlock_irqrestore(&x->wait.lock, flags); 3212} 3213EXPORT_SYMBOL(complete_all); 3214 3215static inline long __sched 3216do_wait_for_common(struct completion *x, long timeout, int state) 3217{ 3218 if (!x->done) { 3219 DECLARE_WAITQUEUE(wait, current); 3220 3221 __add_wait_queue_tail_exclusive(&x->wait, &wait); 3222 do { 3223 if (signal_pending_state(state, current)) { 3224 timeout = -ERESTARTSYS; 3225 break; 3226 } 3227 __set_current_state(state); 3228 spin_unlock_irq(&x->wait.lock); 3229 timeout = schedule_timeout(timeout); 3230 spin_lock_irq(&x->wait.lock); 3231 } while (!x->done && timeout); 3232 __remove_wait_queue(&x->wait, &wait); 3233 if (!x->done) 3234 return timeout; 3235 } 3236 x->done--; 3237 return timeout ?: 1; 3238} 3239 3240static long __sched 3241wait_for_common(struct completion *x, long timeout, int state) 3242{ 3243 might_sleep(); 3244 3245 spin_lock_irq(&x->wait.lock); 3246 timeout = do_wait_for_common(x, timeout, state); 3247 spin_unlock_irq(&x->wait.lock); 3248 return timeout; 3249} 3250 3251/** 3252 * wait_for_completion: - waits for completion of a task 3253 * @x: holds the state of this particular completion 3254 * 3255 * This waits to be signaled for completion of a specific task. It is NOT 3256 * interruptible and there is no timeout. 3257 * 3258 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout 3259 * and interrupt capability. Also see complete(). 3260 */ 3261void __sched wait_for_completion(struct completion *x) 3262{ 3263 wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE); 3264} 3265EXPORT_SYMBOL(wait_for_completion); 3266 3267/** 3268 * wait_for_completion_timeout: - waits for completion of a task (w/timeout) 3269 * @x: holds the state of this particular completion 3270 * @timeout: timeout value in jiffies 3271 * 3272 * This waits for either a completion of a specific task to be signaled or for a 3273 * specified timeout to expire. The timeout is in jiffies. It is not 3274 * interruptible. 3275 * 3276 * The return value is 0 if timed out, and positive (at least 1, or number of 3277 * jiffies left till timeout) if completed. 3278 */ 3279unsigned long __sched 3280wait_for_completion_timeout(struct completion *x, unsigned long timeout) 3281{ 3282 return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE); 3283} 3284EXPORT_SYMBOL(wait_for_completion_timeout); 3285 3286/** 3287 * wait_for_completion_interruptible: - waits for completion of a task (w/intr) 3288 * @x: holds the state of this particular completion 3289 * 3290 * This waits for completion of a specific task to be signaled. It is 3291 * interruptible. 3292 * 3293 * The return value is -ERESTARTSYS if interrupted, 0 if completed. 3294 */ 3295int __sched wait_for_completion_interruptible(struct completion *x) 3296{ 3297 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE); 3298 if (t == -ERESTARTSYS) 3299 return t; 3300 return 0; 3301} 3302EXPORT_SYMBOL(wait_for_completion_interruptible); 3303 3304/** 3305 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr)) 3306 * @x: holds the state of this particular completion 3307 * @timeout: timeout value in jiffies 3308 * 3309 * This waits for either a completion of a specific task to be signaled or for a 3310 * specified timeout to expire. It is interruptible. The timeout is in jiffies. 3311 * 3312 * The return value is -ERESTARTSYS if interrupted, 0 if timed out, 3313 * positive (at least 1, or number of jiffies left till timeout) if completed. 3314 */ 3315long __sched 3316wait_for_completion_interruptible_timeout(struct completion *x, 3317 unsigned long timeout) 3318{ 3319 return wait_for_common(x, timeout, TASK_INTERRUPTIBLE); 3320} 3321EXPORT_SYMBOL(wait_for_completion_interruptible_timeout); 3322 3323/** 3324 * wait_for_completion_killable: - waits for completion of a task (killable) 3325 * @x: holds the state of this particular completion 3326 * 3327 * This waits to be signaled for completion of a specific task. It can be 3328 * interrupted by a kill signal. 3329 * 3330 * The return value is -ERESTARTSYS if interrupted, 0 if completed. 3331 */ 3332int __sched wait_for_completion_killable(struct completion *x) 3333{ 3334 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE); 3335 if (t == -ERESTARTSYS) 3336 return t; 3337 return 0; 3338} 3339EXPORT_SYMBOL(wait_for_completion_killable); 3340 3341/** 3342 * wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable)) 3343 * @x: holds the state of this particular completion 3344 * @timeout: timeout value in jiffies 3345 * 3346 * This waits for either a completion of a specific task to be 3347 * signaled or for a specified timeout to expire. It can be 3348 * interrupted by a kill signal. The timeout is in jiffies. 3349 * 3350 * The return value is -ERESTARTSYS if interrupted, 0 if timed out, 3351 * positive (at least 1, or number of jiffies left till timeout) if completed. 3352 */ 3353long __sched 3354wait_for_completion_killable_timeout(struct completion *x, 3355 unsigned long timeout) 3356{ 3357 return wait_for_common(x, timeout, TASK_KILLABLE); 3358} 3359EXPORT_SYMBOL(wait_for_completion_killable_timeout); 3360 3361/** 3362 * try_wait_for_completion - try to decrement a completion without blocking 3363 * @x: completion structure 3364 * 3365 * Returns: 0 if a decrement cannot be done without blocking 3366 * 1 if a decrement succeeded. 3367 * 3368 * If a completion is being used as a counting completion, 3369 * attempt to decrement the counter without blocking. This 3370 * enables us to avoid waiting if the resource the completion 3371 * is protecting is not available. 3372 */ 3373bool try_wait_for_completion(struct completion *x) 3374{ 3375 unsigned long flags; 3376 int ret = 1; 3377 3378 spin_lock_irqsave(&x->wait.lock, flags); 3379 if (!x->done) 3380 ret = 0; 3381 else 3382 x->done--; 3383 spin_unlock_irqrestore(&x->wait.lock, flags); 3384 return ret; 3385} 3386EXPORT_SYMBOL(try_wait_for_completion); 3387 3388/** 3389 * completion_done - Test to see if a completion has any waiters 3390 * @x: completion structure 3391 * 3392 * Returns: 0 if there are waiters (wait_for_completion() in progress) 3393 * 1 if there are no waiters. 3394 * 3395 */ 3396bool completion_done(struct completion *x) 3397{ 3398 unsigned long flags; 3399 int ret = 1; 3400 3401 spin_lock_irqsave(&x->wait.lock, flags); 3402 if (!x->done) 3403 ret = 0; 3404 spin_unlock_irqrestore(&x->wait.lock, flags); 3405 return ret; 3406} 3407EXPORT_SYMBOL(completion_done); 3408 3409static long __sched 3410sleep_on_common(wait_queue_head_t *q, int state, long timeout) 3411{ 3412 unsigned long flags; 3413 wait_queue_t wait; 3414 3415 init_waitqueue_entry(&wait, current); 3416 3417 __set_current_state(state); 3418 3419 spin_lock_irqsave(&q->lock, flags); 3420 __add_wait_queue(q, &wait); 3421 spin_unlock(&q->lock); 3422 timeout = schedule_timeout(timeout); 3423 spin_lock_irq(&q->lock); 3424 __remove_wait_queue(q, &wait); 3425 spin_unlock_irqrestore(&q->lock, flags); 3426 3427 return timeout; 3428} 3429 3430void __sched interruptible_sleep_on(wait_queue_head_t *q) 3431{ 3432 sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); 3433} 3434EXPORT_SYMBOL(interruptible_sleep_on); 3435 3436long __sched 3437interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout) 3438{ 3439 return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout); 3440} 3441EXPORT_SYMBOL(interruptible_sleep_on_timeout); 3442 3443void __sched sleep_on(wait_queue_head_t *q) 3444{ 3445 sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); 3446} 3447EXPORT_SYMBOL(sleep_on); 3448 3449long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout) 3450{ 3451 return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout); 3452} 3453EXPORT_SYMBOL(sleep_on_timeout); 3454 3455#ifdef CONFIG_RT_MUTEXES 3456 3457/* 3458 * rt_mutex_setprio - set the current priority of a task 3459 * @p: task 3460 * @prio: prio value (kernel-internal form) 3461 * 3462 * This function changes the 'effective' priority of a task. It does 3463 * not touch ->normal_prio like __setscheduler(). 3464 * 3465 * Used by the rt_mutex code to implement priority inheritance logic. 3466 */ 3467void rt_mutex_setprio(struct task_struct *p, int prio) 3468{ 3469 int oldprio, on_rq, running; 3470 struct rq *rq; 3471 const struct sched_class *prev_class; 3472 3473 BUG_ON(prio < 0 || prio > MAX_PRIO); 3474 3475 rq = __task_rq_lock(p); 3476 3477 /* 3478 * Idle task boosting is a nono in general. There is one 3479 * exception, when PREEMPT_RT and NOHZ is active: 3480 * 3481 * The idle task calls get_next_timer_interrupt() and holds 3482 * the timer wheel base->lock on the CPU and another CPU wants 3483 * to access the timer (probably to cancel it). We can safely 3484 * ignore the boosting request, as the idle CPU runs this code 3485 * with interrupts disabled and will complete the lock 3486 * protected section without being interrupted. So there is no 3487 * real need to boost. 3488 */ 3489 if (unlikely(p == rq->idle)) { 3490 WARN_ON(p != rq->curr); 3491 WARN_ON(p->pi_blocked_on); 3492 goto out_unlock; 3493 } 3494 3495 trace_sched_pi_setprio(p, prio); 3496 oldprio = p->prio; 3497 prev_class = p->sched_class; 3498 on_rq = p->on_rq; 3499 running = task_current(rq, p); 3500 if (on_rq) 3501 dequeue_task(rq, p, 0); 3502 if (running) 3503 p->sched_class->put_prev_task(rq, p); 3504 3505 if (rt_prio(prio)) 3506 p->sched_class = &rt_sched_class; 3507 else 3508 p->sched_class = &fair_sched_class; 3509 3510 p->prio = prio; 3511 3512 if (running) 3513 p->sched_class->set_curr_task(rq); 3514 if (on_rq) 3515 enqueue_task(rq, p, oldprio < prio ? ENQUEUE_HEAD : 0); 3516 3517 check_class_changed(rq, p, prev_class, oldprio); 3518out_unlock: 3519 __task_rq_unlock(rq); 3520} 3521#endif 3522void set_user_nice(struct task_struct *p, long nice) 3523{ 3524 int old_prio, delta, on_rq; 3525 unsigned long flags; 3526 struct rq *rq; 3527 3528 if (TASK_NICE(p) == nice || nice < -20 || nice > 19) 3529 return; 3530 /* 3531 * We have to be careful, if called from sys_setpriority(), 3532 * the task might be in the middle of scheduling on another CPU. 3533 */ 3534 rq = task_rq_lock(p, &flags); 3535 /* 3536 * The RT priorities are set via sched_setscheduler(), but we still 3537 * allow the 'normal' nice value to be set - but as expected 3538 * it wont have any effect on scheduling until the task is 3539 * SCHED_FIFO/SCHED_RR: 3540 */ 3541 if (task_has_rt_policy(p)) { 3542 p->static_prio = NICE_TO_PRIO(nice); 3543 goto out_unlock; 3544 } 3545 on_rq = p->on_rq; 3546 if (on_rq) 3547 dequeue_task(rq, p, 0); 3548 3549 p->static_prio = NICE_TO_PRIO(nice); 3550 set_load_weight(p); 3551 old_prio = p->prio; 3552 p->prio = effective_prio(p); 3553 delta = p->prio - old_prio; 3554 3555 if (on_rq) { 3556 enqueue_task(rq, p, 0); 3557 /* 3558 * If the task increased its priority or is running and 3559 * lowered its priority, then reschedule its CPU: 3560 */ 3561 if (delta < 0 || (delta > 0 && task_running(rq, p))) 3562 resched_task(rq->curr); 3563 } 3564out_unlock: 3565 task_rq_unlock(rq, p, &flags); 3566} 3567EXPORT_SYMBOL(set_user_nice); 3568 3569/* 3570 * can_nice - check if a task can reduce its nice value 3571 * @p: task 3572 * @nice: nice value 3573 */ 3574int can_nice(const struct task_struct *p, const int nice) 3575{ 3576 /* convert nice value [19,-20] to rlimit style value [1,40] */ 3577 int nice_rlim = 20 - nice; 3578 3579 return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) || 3580 capable(CAP_SYS_NICE)); 3581} 3582 3583#ifdef __ARCH_WANT_SYS_NICE 3584 3585/* 3586 * sys_nice - change the priority of the current process. 3587 * @increment: priority increment 3588 * 3589 * sys_setpriority is a more generic, but much slower function that 3590 * does similar things. 3591 */ 3592SYSCALL_DEFINE1(nice, int, increment) 3593{ 3594 long nice, retval; 3595 3596 /* 3597 * Setpriority might change our priority at the same moment. 3598 * We don't have to worry. Conceptually one call occurs first 3599 * and we have a single winner. 3600 */ 3601 if (increment < -40) 3602 increment = -40; 3603 if (increment > 40) 3604 increment = 40; 3605 3606 nice = TASK_NICE(current) + increment; 3607 if (nice < -20) 3608 nice = -20; 3609 if (nice > 19) 3610 nice = 19; 3611 3612 if (increment < 0 && !can_nice(current, nice)) 3613 return -EPERM; 3614 3615 retval = security_task_setnice(current, nice); 3616 if (retval) 3617 return retval; 3618 3619 set_user_nice(current, nice); 3620 return 0; 3621} 3622 3623#endif 3624 3625/** 3626 * task_prio - return the priority value of a given task. 3627 * @p: the task in question. 3628 * 3629 * This is the priority value as seen by users in /proc. 3630 * RT tasks are offset by -200. Normal tasks are centered 3631 * around 0, value goes from -16 to +15. 3632 */ 3633int task_prio(const struct task_struct *p) 3634{ 3635 return p->prio - MAX_RT_PRIO; 3636} 3637 3638/** 3639 * task_nice - return the nice value of a given task. 3640 * @p: the task in question. 3641 */ 3642int task_nice(const struct task_struct *p) 3643{ 3644 return TASK_NICE(p); 3645} 3646EXPORT_SYMBOL(task_nice); 3647 3648/** 3649 * idle_cpu - is a given cpu idle currently? 3650 * @cpu: the processor in question. 3651 */ 3652int idle_cpu(int cpu) 3653{ 3654 struct rq *rq = cpu_rq(cpu); 3655 3656 if (rq->curr != rq->idle) 3657 return 0; 3658 3659 if (rq->nr_running) 3660 return 0; 3661 3662#ifdef CONFIG_SMP 3663 if (!llist_empty(&rq->wake_list)) 3664 return 0; 3665#endif 3666 3667 return 1; 3668} 3669 3670/** 3671 * idle_task - return the idle task for a given cpu. 3672 * @cpu: the processor in question. 3673 */ 3674struct task_struct *idle_task(int cpu) 3675{ 3676 return cpu_rq(cpu)->idle; 3677} 3678 3679/** 3680 * find_process_by_pid - find a process with a matching PID value. 3681 * @pid: the pid in question. 3682 */ 3683static struct task_struct *find_process_by_pid(pid_t pid) 3684{ 3685 return pid ? find_task_by_vpid(pid) : current; 3686} 3687 3688/* Actually do priority change: must hold rq lock. */ 3689static void 3690__setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio) 3691{ 3692 p->policy = policy; 3693 p->rt_priority = prio; 3694 p->normal_prio = normal_prio(p); 3695 /* we are holding p->pi_lock already */ 3696 p->prio = rt_mutex_getprio(p); 3697 if (rt_prio(p->prio)) 3698 p->sched_class = &rt_sched_class; 3699 else 3700 p->sched_class = &fair_sched_class; 3701 set_load_weight(p); 3702} 3703 3704/* 3705 * check the target process has a UID that matches the current process's 3706 */ 3707static bool check_same_owner(struct task_struct *p) 3708{ 3709 const struct cred *cred = current_cred(), *pcred; 3710 bool match; 3711 3712 rcu_read_lock(); 3713 pcred = __task_cred(p); 3714 match = (uid_eq(cred->euid, pcred->euid) || 3715 uid_eq(cred->euid, pcred->uid)); 3716 rcu_read_unlock(); 3717 return match; 3718} 3719 3720static int __sched_setscheduler(struct task_struct *p, int policy, 3721 const struct sched_param *param, bool user) 3722{ 3723 int retval, oldprio, oldpolicy = -1, on_rq, running; 3724 unsigned long flags; 3725 const struct sched_class *prev_class; 3726 struct rq *rq; 3727 int reset_on_fork; 3728 3729 /* may grab non-irq protected spin_locks */ 3730 BUG_ON(in_interrupt()); 3731recheck: 3732 /* double check policy once rq lock held */ 3733 if (policy < 0) { 3734 reset_on_fork = p->sched_reset_on_fork; 3735 policy = oldpolicy = p->policy; 3736 } else { 3737 reset_on_fork = !!(policy & SCHED_RESET_ON_FORK); 3738 policy &= ~SCHED_RESET_ON_FORK; 3739 3740 if (policy != SCHED_FIFO && policy != SCHED_RR && 3741 policy != SCHED_NORMAL && policy != SCHED_BATCH && 3742 policy != SCHED_IDLE) 3743 return -EINVAL; 3744 } 3745 3746 /* 3747 * Valid priorities for SCHED_FIFO and SCHED_RR are 3748 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL, 3749 * SCHED_BATCH and SCHED_IDLE is 0. 3750 */ 3751 if (param->sched_priority < 0 || 3752 (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) || 3753 (!p->mm && param->sched_priority > MAX_RT_PRIO-1)) 3754 return -EINVAL; 3755 if (rt_policy(policy) != (param->sched_priority != 0)) 3756 return -EINVAL; 3757 3758 /* 3759 * Allow unprivileged RT tasks to decrease priority: 3760 */ 3761 if (user && !capable(CAP_SYS_NICE)) { 3762 if (rt_policy(policy)) { 3763 unsigned long rlim_rtprio = 3764 task_rlimit(p, RLIMIT_RTPRIO); 3765 3766 /* can't set/change the rt policy */ 3767 if (policy != p->policy && !rlim_rtprio) 3768 return -EPERM; 3769 3770 /* can't increase priority */ 3771 if (param->sched_priority > p->rt_priority && 3772 param->sched_priority > rlim_rtprio) 3773 return -EPERM; 3774 } 3775 3776 /* 3777 * Treat SCHED_IDLE as nice 20. Only allow a switch to 3778 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it. 3779 */ 3780 if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) { 3781 if (!can_nice(p, TASK_NICE(p))) 3782 return -EPERM; 3783 } 3784 3785 /* can't change other user's priorities */ 3786 if (!check_same_owner(p)) 3787 return -EPERM; 3788 3789 /* Normal users shall not reset the sched_reset_on_fork flag */ 3790 if (p->sched_reset_on_fork && !reset_on_fork) 3791 return -EPERM; 3792 } 3793 3794 if (user) { 3795 retval = security_task_setscheduler(p); 3796 if (retval) 3797 return retval; 3798 } 3799 3800 /* 3801 * make sure no PI-waiters arrive (or leave) while we are 3802 * changing the priority of the task: 3803 * 3804 * To be able to change p->policy safely, the appropriate 3805 * runqueue lock must be held. 3806 */ 3807 rq = task_rq_lock(p, &flags); 3808 3809 /* 3810 * Changing the policy of the stop threads its a very bad idea 3811 */ 3812 if (p == rq->stop) { 3813 task_rq_unlock(rq, p, &flags); 3814 return -EINVAL; 3815 } 3816 3817 /* 3818 * If not changing anything there's no need to proceed further: 3819 */ 3820 if (unlikely(policy == p->policy && (!rt_policy(policy) || 3821 param->sched_priority == p->rt_priority))) { 3822 task_rq_unlock(rq, p, &flags); 3823 return 0; 3824 } 3825 3826#ifdef CONFIG_RT_GROUP_SCHED 3827 if (user) { 3828 /* 3829 * Do not allow realtime tasks into groups that have no runtime 3830 * assigned. 3831 */ 3832 if (rt_bandwidth_enabled() && rt_policy(policy) && 3833 task_group(p)->rt_bandwidth.rt_runtime == 0 && 3834 !task_group_is_autogroup(task_group(p))) { 3835 task_rq_unlock(rq, p, &flags); 3836 return -EPERM; 3837 } 3838 } 3839#endif 3840 3841 /* recheck policy now with rq lock held */ 3842 if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { 3843 policy = oldpolicy = -1; 3844 task_rq_unlock(rq, p, &flags); 3845 goto recheck; 3846 } 3847 on_rq = p->on_rq; 3848 running = task_current(rq, p); 3849 if (on_rq) 3850 dequeue_task(rq, p, 0); 3851 if (running) 3852 p->sched_class->put_prev_task(rq, p); 3853 3854 p->sched_reset_on_fork = reset_on_fork; 3855 3856 oldprio = p->prio; 3857 prev_class = p->sched_class; 3858 __setscheduler(rq, p, policy, param->sched_priority); 3859 3860 if (running) 3861 p->sched_class->set_curr_task(rq); 3862 if (on_rq) 3863 enqueue_task(rq, p, 0); 3864 3865 check_class_changed(rq, p, prev_class, oldprio); 3866 task_rq_unlock(rq, p, &flags); 3867 3868 rt_mutex_adjust_pi(p); 3869 3870 return 0; 3871} 3872 3873/** 3874 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. 3875 * @p: the task in question. 3876 * @policy: new policy. 3877 * @param: structure containing the new RT priority. 3878 * 3879 * NOTE that the task may be already dead. 3880 */ 3881int sched_setscheduler(struct task_struct *p, int policy, 3882 const struct sched_param *param) 3883{ 3884 return __sched_setscheduler(p, policy, param, true); 3885} 3886EXPORT_SYMBOL_GPL(sched_setscheduler); 3887 3888/** 3889 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace. 3890 * @p: the task in question. 3891 * @policy: new policy. 3892 * @param: structure containing the new RT priority. 3893 * 3894 * Just like sched_setscheduler, only don't bother checking if the 3895 * current context has permission. For example, this is needed in 3896 * stop_machine(): we create temporary high priority worker threads, 3897 * but our caller might not have that capability. 3898 */ 3899int sched_setscheduler_nocheck(struct task_struct *p, int policy, 3900 const struct sched_param *param) 3901{ 3902 return __sched_setscheduler(p, policy, param, false); 3903} 3904 3905static int 3906do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) 3907{ 3908 struct sched_param lparam; 3909 struct task_struct *p; 3910 int retval; 3911 3912 if (!param || pid < 0) 3913 return -EINVAL; 3914 if (copy_from_user(&lparam, param, sizeof(struct sched_param))) 3915 return -EFAULT; 3916 3917 rcu_read_lock(); 3918 retval = -ESRCH; 3919 p = find_process_by_pid(pid); 3920 if (p != NULL) 3921 retval = sched_setscheduler(p, policy, &lparam); 3922 rcu_read_unlock(); 3923 3924 return retval; 3925} 3926 3927/** 3928 * sys_sched_setscheduler - set/change the scheduler policy and RT priority 3929 * @pid: the pid in question. 3930 * @policy: new policy. 3931 * @param: structure containing the new RT priority. 3932 */ 3933SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy, 3934 struct sched_param __user *, param) 3935{ 3936 /* negative values for policy are not valid */ 3937 if (policy < 0) 3938 return -EINVAL; 3939 3940 return do_sched_setscheduler(pid, policy, param); 3941} 3942 3943/** 3944 * sys_sched_setparam - set/change the RT priority of a thread 3945 * @pid: the pid in question. 3946 * @param: structure containing the new RT priority. 3947 */ 3948SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param) 3949{ 3950 return do_sched_setscheduler(pid, -1, param); 3951} 3952 3953/** 3954 * sys_sched_getscheduler - get the policy (scheduling class) of a thread 3955 * @pid: the pid in question. 3956 */ 3957SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid) 3958{ 3959 struct task_struct *p; 3960 int retval; 3961 3962 if (pid < 0) 3963 return -EINVAL; 3964 3965 retval = -ESRCH; 3966 rcu_read_lock(); 3967 p = find_process_by_pid(pid); 3968 if (p) { 3969 retval = security_task_getscheduler(p); 3970 if (!retval) 3971 retval = p->policy 3972 | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0); 3973 } 3974 rcu_read_unlock(); 3975 return retval; 3976} 3977 3978/** 3979 * sys_sched_getparam - get the RT priority of a thread 3980 * @pid: the pid in question. 3981 * @param: structure containing the RT priority. 3982 */ 3983SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param) 3984{ 3985 struct sched_param lp; 3986 struct task_struct *p; 3987 int retval; 3988 3989 if (!param || pid < 0) 3990 return -EINVAL; 3991 3992 rcu_read_lock(); 3993 p = find_process_by_pid(pid); 3994 retval = -ESRCH; 3995 if (!p) 3996 goto out_unlock; 3997 3998 retval = security_task_getscheduler(p); 3999 if (retval) 4000 goto out_unlock; 4001 4002 lp.sched_priority = p->rt_priority; 4003 rcu_read_unlock(); 4004 4005 /* 4006 * This one might sleep, we cannot do it with a spinlock held ... 4007 */ 4008 retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; 4009 4010 return retval; 4011 4012out_unlock: 4013 rcu_read_unlock(); 4014 return retval; 4015} 4016 4017long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) 4018{ 4019 cpumask_var_t cpus_allowed, new_mask; 4020 struct task_struct *p; 4021 int retval; 4022 4023 get_online_cpus(); 4024 rcu_read_lock(); 4025 4026 p = find_process_by_pid(pid); 4027 if (!p) { 4028 rcu_read_unlock(); 4029 put_online_cpus(); 4030 return -ESRCH; 4031 } 4032 4033 /* Prevent p going away */ 4034 get_task_struct(p); 4035 rcu_read_unlock(); 4036 4037 if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) { 4038 retval = -ENOMEM; 4039 goto out_put_task; 4040 } 4041 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) { 4042 retval = -ENOMEM; 4043 goto out_free_cpus_allowed; 4044 } 4045 retval = -EPERM; 4046 if (!check_same_owner(p) && !ns_capable(task_user_ns(p), CAP_SYS_NICE)) 4047 goto out_unlock; 4048 4049 retval = security_task_setscheduler(p); 4050 if (retval) 4051 goto out_unlock; 4052 4053 cpuset_cpus_allowed(p, cpus_allowed); 4054 cpumask_and(new_mask, in_mask, cpus_allowed); 4055again: 4056 retval = set_cpus_allowed_ptr(p, new_mask); 4057 4058 if (!retval) { 4059 cpuset_cpus_allowed(p, cpus_allowed); 4060 if (!cpumask_subset(new_mask, cpus_allowed)) { 4061 /* 4062 * We must have raced with a concurrent cpuset 4063 * update. Just reset the cpus_allowed to the 4064 * cpuset's cpus_allowed 4065 */ 4066 cpumask_copy(new_mask, cpus_allowed); 4067 goto again; 4068 } 4069 } 4070out_unlock: 4071 free_cpumask_var(new_mask); 4072out_free_cpus_allowed: 4073 free_cpumask_var(cpus_allowed); 4074out_put_task: 4075 put_task_struct(p); 4076 put_online_cpus(); 4077 return retval; 4078} 4079 4080static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, 4081 struct cpumask *new_mask) 4082{ 4083 if (len < cpumask_size()) 4084 cpumask_clear(new_mask); 4085 else if (len > cpumask_size()) 4086 len = cpumask_size(); 4087 4088 return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; 4089} 4090 4091/** 4092 * sys_sched_setaffinity - set the cpu affinity of a process 4093 * @pid: pid of the process 4094 * @len: length in bytes of the bitmask pointed to by user_mask_ptr 4095 * @user_mask_ptr: user-space pointer to the new cpu mask 4096 */ 4097SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len, 4098 unsigned long __user *, user_mask_ptr) 4099{ 4100 cpumask_var_t new_mask; 4101 int retval; 4102 4103 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) 4104 return -ENOMEM; 4105 4106 retval = get_user_cpu_mask(user_mask_ptr, len, new_mask); 4107 if (retval == 0) 4108 retval = sched_setaffinity(pid, new_mask); 4109 free_cpumask_var(new_mask); 4110 return retval; 4111} 4112 4113long sched_getaffinity(pid_t pid, struct cpumask *mask) 4114{ 4115 struct task_struct *p; 4116 unsigned long flags; 4117 int retval; 4118 4119 get_online_cpus(); 4120 rcu_read_lock(); 4121 4122 retval = -ESRCH; 4123 p = find_process_by_pid(pid); 4124 if (!p) 4125 goto out_unlock; 4126 4127 retval = security_task_getscheduler(p); 4128 if (retval) 4129 goto out_unlock; 4130 4131 raw_spin_lock_irqsave(&p->pi_lock, flags); 4132 cpumask_and(mask, &p->cpus_allowed, cpu_online_mask); 4133 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 4134 4135out_unlock: 4136 rcu_read_unlock(); 4137 put_online_cpus(); 4138 4139 return retval; 4140} 4141 4142/** 4143 * sys_sched_getaffinity - get the cpu affinity of a process 4144 * @pid: pid of the process 4145 * @len: length in bytes of the bitmask pointed to by user_mask_ptr 4146 * @user_mask_ptr: user-space pointer to hold the current cpu mask 4147 */ 4148SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len, 4149 unsigned long __user *, user_mask_ptr) 4150{ 4151 int ret; 4152 cpumask_var_t mask; 4153 4154 if ((len * BITS_PER_BYTE) < nr_cpu_ids) 4155 return -EINVAL; 4156 if (len & (sizeof(unsigned long)-1)) 4157 return -EINVAL; 4158 4159 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) 4160 return -ENOMEM; 4161 4162 ret = sched_getaffinity(pid, mask); 4163 if (ret == 0) { 4164 size_t retlen = min_t(size_t, len, cpumask_size()); 4165 4166 if (copy_to_user(user_mask_ptr, mask, retlen)) 4167 ret = -EFAULT; 4168 else 4169 ret = retlen; 4170 } 4171 free_cpumask_var(mask); 4172 4173 return ret; 4174} 4175 4176/** 4177 * sys_sched_yield - yield the current processor to other threads. 4178 * 4179 * This function yields the current CPU to other tasks. If there are no 4180 * other threads running on this CPU then this function will return. 4181 */ 4182SYSCALL_DEFINE0(sched_yield) 4183{ 4184 struct rq *rq = this_rq_lock(); 4185 4186 schedstat_inc(rq, yld_count); 4187 current->sched_class->yield_task(rq); 4188 4189 /* 4190 * Since we are going to call schedule() anyway, there's 4191 * no need to preempt or enable interrupts: 4192 */ 4193 __release(rq->lock); 4194 spin_release(&rq->lock.dep_map, 1, _THIS_IP_); 4195 do_raw_spin_unlock(&rq->lock); 4196 sched_preempt_enable_no_resched(); 4197 4198 schedule(); 4199 4200 return 0; 4201} 4202 4203static inline int should_resched(void) 4204{ 4205 return need_resched() && !(preempt_count() & PREEMPT_ACTIVE); 4206} 4207 4208static void __cond_resched(void) 4209{ 4210 add_preempt_count(PREEMPT_ACTIVE); 4211 __schedule(); 4212 sub_preempt_count(PREEMPT_ACTIVE); 4213} 4214 4215int __sched _cond_resched(void) 4216{ 4217 if (should_resched()) { 4218 __cond_resched(); 4219 return 1; 4220 } 4221 return 0; 4222} 4223EXPORT_SYMBOL(_cond_resched); 4224 4225/* 4226 * __cond_resched_lock() - if a reschedule is pending, drop the given lock, 4227 * call schedule, and on return reacquire the lock. 4228 * 4229 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level 4230 * operations here to prevent schedule() from being called twice (once via 4231 * spin_unlock(), once by hand). 4232 */ 4233int __cond_resched_lock(spinlock_t *lock) 4234{ 4235 int resched = should_resched(); 4236 int ret = 0; 4237 4238 lockdep_assert_held(lock); 4239 4240 if (spin_needbreak(lock) || resched) { 4241 spin_unlock(lock); 4242 if (resched) 4243 __cond_resched(); 4244 else 4245 cpu_relax(); 4246 ret = 1; 4247 spin_lock(lock); 4248 } 4249 return ret; 4250} 4251EXPORT_SYMBOL(__cond_resched_lock); 4252 4253int __sched __cond_resched_softirq(void) 4254{ 4255 BUG_ON(!in_softirq()); 4256 4257 if (should_resched()) { 4258 local_bh_enable(); 4259 __cond_resched(); 4260 local_bh_disable(); 4261 return 1; 4262 } 4263 return 0; 4264} 4265EXPORT_SYMBOL(__cond_resched_softirq); 4266 4267/** 4268 * yield - yield the current processor to other threads. 4269 * 4270 * Do not ever use this function, there's a 99% chance you're doing it wrong. 4271 * 4272 * The scheduler is at all times free to pick the calling task as the most 4273 * eligible task to run, if removing the yield() call from your code breaks 4274 * it, its already broken. 4275 * 4276 * Typical broken usage is: 4277 * 4278 * while (!event) 4279 * yield(); 4280 * 4281 * where one assumes that yield() will let 'the other' process run that will 4282 * make event true. If the current task is a SCHED_FIFO task that will never 4283 * happen. Never use yield() as a progress guarantee!! 4284 * 4285 * If you want to use yield() to wait for something, use wait_event(). 4286 * If you want to use yield() to be 'nice' for others, use cond_resched(). 4287 * If you still want to use yield(), do not! 4288 */ 4289void __sched yield(void) 4290{ 4291 set_current_state(TASK_RUNNING); 4292 sys_sched_yield(); 4293} 4294EXPORT_SYMBOL(yield); 4295 4296/** 4297 * yield_to - yield the current processor to another thread in 4298 * your thread group, or accelerate that thread toward the 4299 * processor it's on. 4300 * @p: target task 4301 * @preempt: whether task preemption is allowed or not 4302 * 4303 * It's the caller's job to ensure that the target task struct 4304 * can't go away on us before we can do any checks. 4305 * 4306 * Returns true if we indeed boosted the target task. 4307 */ 4308bool __sched yield_to(struct task_struct *p, bool preempt) 4309{ 4310 struct task_struct *curr = current; 4311 struct rq *rq, *p_rq; 4312 unsigned long flags; 4313 bool yielded = 0; 4314 4315 local_irq_save(flags); 4316 rq = this_rq(); 4317 4318again: 4319 p_rq = task_rq(p); 4320 double_rq_lock(rq, p_rq); 4321 while (task_rq(p) != p_rq) { 4322 double_rq_unlock(rq, p_rq); 4323 goto again; 4324 } 4325 4326 if (!curr->sched_class->yield_to_task) 4327 goto out; 4328 4329 if (curr->sched_class != p->sched_class) 4330 goto out; 4331 4332 if (task_running(p_rq, p) || p->state) 4333 goto out; 4334 4335 yielded = curr->sched_class->yield_to_task(rq, p, preempt); 4336 if (yielded) { 4337 schedstat_inc(rq, yld_count); 4338 /* 4339 * Make p's CPU reschedule; pick_next_entity takes care of 4340 * fairness. 4341 */ 4342 if (preempt && rq != p_rq) 4343 resched_task(p_rq->curr); 4344 } 4345 4346out: 4347 double_rq_unlock(rq, p_rq); 4348 local_irq_restore(flags); 4349 4350 if (yielded) 4351 schedule(); 4352 4353 return yielded; 4354} 4355EXPORT_SYMBOL_GPL(yield_to); 4356 4357/* 4358 * This task is about to go to sleep on IO. Increment rq->nr_iowait so 4359 * that process accounting knows that this is a task in IO wait state. 4360 */ 4361void __sched io_schedule(void) 4362{ 4363 struct rq *rq = raw_rq(); 4364 4365 delayacct_blkio_start(); 4366 atomic_inc(&rq->nr_iowait); 4367 blk_flush_plug(current); 4368 current->in_iowait = 1; 4369 schedule(); 4370 current->in_iowait = 0; 4371 atomic_dec(&rq->nr_iowait); 4372 delayacct_blkio_end(); 4373} 4374EXPORT_SYMBOL(io_schedule); 4375 4376long __sched io_schedule_timeout(long timeout) 4377{ 4378 struct rq *rq = raw_rq(); 4379 long ret; 4380 4381 delayacct_blkio_start(); 4382 atomic_inc(&rq->nr_iowait); 4383 blk_flush_plug(current); 4384 current->in_iowait = 1; 4385 ret = schedule_timeout(timeout); 4386 current->in_iowait = 0; 4387 atomic_dec(&rq->nr_iowait); 4388 delayacct_blkio_end(); 4389 return ret; 4390} 4391 4392/** 4393 * sys_sched_get_priority_max - return maximum RT priority. 4394 * @policy: scheduling class. 4395 * 4396 * this syscall returns the maximum rt_priority that can be used 4397 * by a given scheduling class. 4398 */ 4399SYSCALL_DEFINE1(sched_get_priority_max, int, policy) 4400{ 4401 int ret = -EINVAL; 4402 4403 switch (policy) { 4404 case SCHED_FIFO: 4405 case SCHED_RR: 4406 ret = MAX_USER_RT_PRIO-1; 4407 break; 4408 case SCHED_NORMAL: 4409 case SCHED_BATCH: 4410 case SCHED_IDLE: 4411 ret = 0; 4412 break; 4413 } 4414 return ret; 4415} 4416 4417/** 4418 * sys_sched_get_priority_min - return minimum RT priority. 4419 * @policy: scheduling class. 4420 * 4421 * this syscall returns the minimum rt_priority that can be used 4422 * by a given scheduling class. 4423 */ 4424SYSCALL_DEFINE1(sched_get_priority_min, int, policy) 4425{ 4426 int ret = -EINVAL; 4427 4428 switch (policy) { 4429 case SCHED_FIFO: 4430 case SCHED_RR: 4431 ret = 1; 4432 break; 4433 case SCHED_NORMAL: 4434 case SCHED_BATCH: 4435 case SCHED_IDLE: 4436 ret = 0; 4437 } 4438 return ret; 4439} 4440 4441/** 4442 * sys_sched_rr_get_interval - return the default timeslice of a process. 4443 * @pid: pid of the process. 4444 * @interval: userspace pointer to the timeslice value. 4445 * 4446 * this syscall writes the default timeslice value of a given process 4447 * into the user-space timespec buffer. A value of '0' means infinity. 4448 */ 4449SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid, 4450 struct timespec __user *, interval) 4451{ 4452 struct task_struct *p; 4453 unsigned int time_slice; 4454 unsigned long flags; 4455 struct rq *rq; 4456 int retval; 4457 struct timespec t; 4458 4459 if (pid < 0) 4460 return -EINVAL; 4461 4462 retval = -ESRCH; 4463 rcu_read_lock(); 4464 p = find_process_by_pid(pid); 4465 if (!p) 4466 goto out_unlock; 4467 4468 retval = security_task_getscheduler(p); 4469 if (retval) 4470 goto out_unlock; 4471 4472 rq = task_rq_lock(p, &flags); 4473 time_slice = p->sched_class->get_rr_interval(rq, p); 4474 task_rq_unlock(rq, p, &flags); 4475 4476 rcu_read_unlock(); 4477 jiffies_to_timespec(time_slice, &t); 4478 retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; 4479 return retval; 4480 4481out_unlock: 4482 rcu_read_unlock(); 4483 return retval; 4484} 4485 4486static const char stat_nam[] = TASK_STATE_TO_CHAR_STR; 4487 4488void sched_show_task(struct task_struct *p) 4489{ 4490 unsigned long free = 0; 4491 unsigned state; 4492 4493 state = p->state ? __ffs(p->state) + 1 : 0; 4494 printk(KERN_INFO "%-15.15s %c", p->comm, 4495 state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); 4496#if BITS_PER_LONG == 32 4497 if (state == TASK_RUNNING) 4498 printk(KERN_CONT " running "); 4499 else 4500 printk(KERN_CONT " %08lx ", thread_saved_pc(p)); 4501#else 4502 if (state == TASK_RUNNING) 4503 printk(KERN_CONT " running task "); 4504 else 4505 printk(KERN_CONT " %016lx ", thread_saved_pc(p)); 4506#endif 4507#ifdef CONFIG_DEBUG_STACK_USAGE 4508 free = stack_not_used(p); 4509#endif 4510 printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free, 4511 task_pid_nr(p), task_pid_nr(rcu_dereference(p->real_parent)), 4512 (unsigned long)task_thread_info(p)->flags); 4513 4514 show_stack(p, NULL); 4515} 4516 4517void show_state_filter(unsigned long state_filter) 4518{ 4519 struct task_struct *g, *p; 4520 4521#if BITS_PER_LONG == 32 4522 printk(KERN_INFO 4523 " task PC stack pid father\n"); 4524#else 4525 printk(KERN_INFO 4526 " task PC stack pid father\n"); 4527#endif 4528 rcu_read_lock(); 4529 do_each_thread(g, p) { 4530 /* 4531 * reset the NMI-timeout, listing all files on a slow 4532 * console might take a lot of time: 4533 */ 4534 touch_nmi_watchdog(); 4535 if (!state_filter || (p->state & state_filter)) 4536 sched_show_task(p); 4537 } while_each_thread(g, p); 4538 4539 touch_all_softlockup_watchdogs(); 4540 4541#ifdef CONFIG_SCHED_DEBUG 4542 sysrq_sched_debug_show(); 4543#endif 4544 rcu_read_unlock(); 4545 /* 4546 * Only show locks if all tasks are dumped: 4547 */ 4548 if (!state_filter) 4549 debug_show_all_locks(); 4550} 4551 4552void __cpuinit init_idle_bootup_task(struct task_struct *idle) 4553{ 4554 idle->sched_class = &idle_sched_class; 4555} 4556 4557/** 4558 * init_idle - set up an idle thread for a given CPU 4559 * @idle: task in question 4560 * @cpu: cpu the idle task belongs to 4561 * 4562 * NOTE: this function does not set the idle thread's NEED_RESCHED 4563 * flag, to make booting more robust. 4564 */ 4565void __cpuinit init_idle(struct task_struct *idle, int cpu) 4566{ 4567 struct rq *rq = cpu_rq(cpu); 4568 unsigned long flags; 4569 4570 raw_spin_lock_irqsave(&rq->lock, flags); 4571 4572 __sched_fork(idle); 4573 idle->state = TASK_RUNNING; 4574 idle->se.exec_start = sched_clock(); 4575 4576 do_set_cpus_allowed(idle, cpumask_of(cpu)); 4577 /* 4578 * We're having a chicken and egg problem, even though we are 4579 * holding rq->lock, the cpu isn't yet set to this cpu so the 4580 * lockdep check in task_group() will fail. 4581 * 4582 * Similar case to sched_fork(). / Alternatively we could 4583 * use task_rq_lock() here and obtain the other rq->lock. 4584 * 4585 * Silence PROVE_RCU 4586 */ 4587 rcu_read_lock(); 4588 __set_task_cpu(idle, cpu); 4589 rcu_read_unlock(); 4590 4591 rq->curr = rq->idle = idle; 4592#if defined(CONFIG_SMP) 4593 idle->on_cpu = 1; 4594#endif 4595 raw_spin_unlock_irqrestore(&rq->lock, flags); 4596 4597 /* Set the preempt count _outside_ the spinlocks! */ 4598 task_thread_info(idle)->preempt_count = 0; 4599 4600 /* 4601 * The idle tasks have their own, simple scheduling class: 4602 */ 4603 idle->sched_class = &idle_sched_class; 4604 ftrace_graph_init_idle_task(idle, cpu); 4605#if defined(CONFIG_SMP) 4606 sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu); 4607#endif 4608} 4609 4610#ifdef CONFIG_SMP 4611void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) 4612{ 4613 if (p->sched_class && p->sched_class->set_cpus_allowed) 4614 p->sched_class->set_cpus_allowed(p, new_mask); 4615 4616 cpumask_copy(&p->cpus_allowed, new_mask); 4617 p->nr_cpus_allowed = cpumask_weight(new_mask); 4618} 4619 4620/* 4621 * This is how migration works: 4622 * 4623 * 1) we invoke migration_cpu_stop() on the target CPU using 4624 * stop_one_cpu(). 4625 * 2) stopper starts to run (implicitly forcing the migrated thread 4626 * off the CPU) 4627 * 3) it checks whether the migrated task is still in the wrong runqueue. 4628 * 4) if it's in the wrong runqueue then the migration thread removes 4629 * it and puts it into the right queue. 4630 * 5) stopper completes and stop_one_cpu() returns and the migration 4631 * is done. 4632 */ 4633 4634/* 4635 * Change a given task's CPU affinity. Migrate the thread to a 4636 * proper CPU and schedule it away if the CPU it's executing on 4637 * is removed from the allowed bitmask. 4638 * 4639 * NOTE: the caller must have a valid reference to the task, the 4640 * task must not exit() & deallocate itself prematurely. The 4641 * call is not atomic; no spinlocks may be held. 4642 */ 4643int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) 4644{ 4645 unsigned long flags; 4646 struct rq *rq; 4647 unsigned int dest_cpu; 4648 int ret = 0; 4649 4650 rq = task_rq_lock(p, &flags); 4651 4652 if (cpumask_equal(&p->cpus_allowed, new_mask)) 4653 goto out; 4654 4655 if (!cpumask_intersects(new_mask, cpu_active_mask)) { 4656 ret = -EINVAL; 4657 goto out; 4658 } 4659 4660 if (unlikely((p->flags & PF_THREAD_BOUND) && p != current)) { 4661 ret = -EINVAL; 4662 goto out; 4663 } 4664 4665 do_set_cpus_allowed(p, new_mask); 4666 4667 /* Can the task run on the task's current CPU? If so, we're done */ 4668 if (cpumask_test_cpu(task_cpu(p), new_mask)) 4669 goto out; 4670 4671 dest_cpu = cpumask_any_and(cpu_active_mask, new_mask); 4672 if (p->on_rq) { 4673 struct migration_arg arg = { p, dest_cpu }; 4674 /* Need help from migration thread: drop lock and wait. */ 4675 task_rq_unlock(rq, p, &flags); 4676 stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg); 4677 tlb_migrate_finish(p->mm); 4678 return 0; 4679 } 4680out: 4681 task_rq_unlock(rq, p, &flags); 4682 4683 return ret; 4684} 4685EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr); 4686 4687/* 4688 * Move (not current) task off this cpu, onto dest cpu. We're doing 4689 * this because either it can't run here any more (set_cpus_allowed() 4690 * away from this CPU, or CPU going down), or because we're 4691 * attempting to rebalance this task on exec (sched_exec). 4692 * 4693 * So we race with normal scheduler movements, but that's OK, as long 4694 * as the task is no longer on this CPU. 4695 * 4696 * Returns non-zero if task was successfully migrated. 4697 */ 4698static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) 4699{ 4700 struct rq *rq_dest, *rq_src; 4701 int ret = 0; 4702 4703 if (unlikely(!cpu_active(dest_cpu))) 4704 return ret; 4705 4706 rq_src = cpu_rq(src_cpu); 4707 rq_dest = cpu_rq(dest_cpu); 4708 4709 raw_spin_lock(&p->pi_lock); 4710 double_rq_lock(rq_src, rq_dest); 4711 /* Already moved. */ 4712 if (task_cpu(p) != src_cpu) 4713 goto done; 4714 /* Affinity changed (again). */ 4715 if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) 4716 goto fail; 4717 4718 /* 4719 * If we're not on a rq, the next wake-up will ensure we're 4720 * placed properly. 4721 */ 4722 if (p->on_rq) { 4723 dequeue_task(rq_src, p, 0); 4724 set_task_cpu(p, dest_cpu); 4725 enqueue_task(rq_dest, p, 0); 4726 check_preempt_curr(rq_dest, p, 0); 4727 } 4728done: 4729 ret = 1; 4730fail: 4731 double_rq_unlock(rq_src, rq_dest); 4732 raw_spin_unlock(&p->pi_lock); 4733 return ret; 4734} 4735 4736/* 4737 * migration_cpu_stop - this will be executed by a highprio stopper thread 4738 * and performs thread migration by bumping thread off CPU then 4739 * 'pushing' onto another runqueue. 4740 */ 4741static int migration_cpu_stop(void *data) 4742{ 4743 struct migration_arg *arg = data; 4744 4745 /* 4746 * The original target cpu might have gone down and we might 4747 * be on another cpu but it doesn't matter. 4748 */ 4749 local_irq_disable(); 4750 __migrate_task(arg->task, raw_smp_processor_id(), arg->dest_cpu); 4751 local_irq_enable(); 4752 return 0; 4753} 4754 4755#ifdef CONFIG_HOTPLUG_CPU 4756 4757/* 4758 * Ensures that the idle task is using init_mm right before its cpu goes 4759 * offline. 4760 */ 4761void idle_task_exit(void) 4762{ 4763 struct mm_struct *mm = current->active_mm; 4764 4765 BUG_ON(cpu_online(smp_processor_id())); 4766 4767 if (mm != &init_mm) 4768 switch_mm(mm, &init_mm, current); 4769 mmdrop(mm); 4770} 4771 4772/* 4773 * Since this CPU is going 'away' for a while, fold any nr_active delta 4774 * we might have. Assumes we're called after migrate_tasks() so that the 4775 * nr_active count is stable. 4776 * 4777 * Also see the comment "Global load-average calculations". 4778 */ 4779static void calc_load_migrate(struct rq *rq) 4780{ 4781 long delta = calc_load_fold_active(rq); 4782 if (delta) 4783 atomic_long_add(delta, &calc_load_tasks); 4784} 4785 4786/* 4787 * Migrate all tasks from the rq, sleeping tasks will be migrated by 4788 * try_to_wake_up()->select_task_rq(). 4789 * 4790 * Called with rq->lock held even though we'er in stop_machine() and 4791 * there's no concurrency possible, we hold the required locks anyway 4792 * because of lock validation efforts. 4793 */ 4794static void migrate_tasks(unsigned int dead_cpu) 4795{ 4796 struct rq *rq = cpu_rq(dead_cpu); 4797 struct task_struct *next, *stop = rq->stop; 4798 int dest_cpu; 4799 4800 /* 4801 * Fudge the rq selection such that the below task selection loop 4802 * doesn't get stuck on the currently eligible stop task. 4803 * 4804 * We're currently inside stop_machine() and the rq is either stuck 4805 * in the stop_machine_cpu_stop() loop, or we're executing this code, 4806 * either way we should never end up calling schedule() until we're 4807 * done here. 4808 */ 4809 rq->stop = NULL; 4810 4811 for ( ; ; ) { 4812 /* 4813 * There's this thread running, bail when that's the only 4814 * remaining thread. 4815 */ 4816 if (rq->nr_running == 1) 4817 break; 4818 4819 next = pick_next_task(rq); 4820 BUG_ON(!next); 4821 next->sched_class->put_prev_task(rq, next); 4822 4823 /* Find suitable destination for @next, with force if needed. */ 4824 dest_cpu = select_fallback_rq(dead_cpu, next); 4825 raw_spin_unlock(&rq->lock); 4826 4827 __migrate_task(next, dead_cpu, dest_cpu); 4828 4829 raw_spin_lock(&rq->lock); 4830 } 4831 4832 rq->stop = stop; 4833} 4834 4835#endif /* CONFIG_HOTPLUG_CPU */ 4836 4837#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL) 4838 4839static struct ctl_table sd_ctl_dir[] = { 4840 { 4841 .procname = "sched_domain", 4842 .mode = 0555, 4843 }, 4844 {} 4845}; 4846 4847static struct ctl_table sd_ctl_root[] = { 4848 { 4849 .procname = "kernel", 4850 .mode = 0555, 4851 .child = sd_ctl_dir, 4852 }, 4853 {} 4854}; 4855 4856static struct ctl_table *sd_alloc_ctl_entry(int n) 4857{ 4858 struct ctl_table *entry = 4859 kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL); 4860 4861 return entry; 4862} 4863 4864static void sd_free_ctl_entry(struct ctl_table **tablep) 4865{ 4866 struct ctl_table *entry; 4867 4868 /* 4869 * In the intermediate directories, both the child directory and 4870 * procname are dynamically allocated and could fail but the mode 4871 * will always be set. In the lowest directory the names are 4872 * static strings and all have proc handlers. 4873 */ 4874 for (entry = *tablep; entry->mode; entry++) { 4875 if (entry->child) 4876 sd_free_ctl_entry(&entry->child); 4877 if (entry->proc_handler == NULL) 4878 kfree(entry->procname); 4879 } 4880 4881 kfree(*tablep); 4882 *tablep = NULL; 4883} 4884 4885static int min_load_idx = 0; 4886static int max_load_idx = CPU_LOAD_IDX_MAX; 4887 4888static void 4889set_table_entry(struct ctl_table *entry, 4890 const char *procname, void *data, int maxlen, 4891 umode_t mode, proc_handler *proc_handler, 4892 bool load_idx) 4893{ 4894 entry->procname = procname; 4895 entry->data = data; 4896 entry->maxlen = maxlen; 4897 entry->mode = mode; 4898 entry->proc_handler = proc_handler; 4899 4900 if (load_idx) { 4901 entry->extra1 = &min_load_idx; 4902 entry->extra2 = &max_load_idx; 4903 } 4904} 4905 4906static struct ctl_table * 4907sd_alloc_ctl_domain_table(struct sched_domain *sd) 4908{ 4909 struct ctl_table *table = sd_alloc_ctl_entry(13); 4910 4911 if (table == NULL) 4912 return NULL; 4913 4914 set_table_entry(&table[0], "min_interval", &sd->min_interval, 4915 sizeof(long), 0644, proc_doulongvec_minmax, false); 4916 set_table_entry(&table[1], "max_interval", &sd->max_interval, 4917 sizeof(long), 0644, proc_doulongvec_minmax, false); 4918 set_table_entry(&table[2], "busy_idx", &sd->busy_idx, 4919 sizeof(int), 0644, proc_dointvec_minmax, true); 4920 set_table_entry(&table[3], "idle_idx", &sd->idle_idx, 4921 sizeof(int), 0644, proc_dointvec_minmax, true); 4922 set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx, 4923 sizeof(int), 0644, proc_dointvec_minmax, true); 4924 set_table_entry(&table[5], "wake_idx", &sd->wake_idx, 4925 sizeof(int), 0644, proc_dointvec_minmax, true); 4926 set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx, 4927 sizeof(int), 0644, proc_dointvec_minmax, true); 4928 set_table_entry(&table[7], "busy_factor", &sd->busy_factor, 4929 sizeof(int), 0644, proc_dointvec_minmax, false); 4930 set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct, 4931 sizeof(int), 0644, proc_dointvec_minmax, false); 4932 set_table_entry(&table[9], "cache_nice_tries", 4933 &sd->cache_nice_tries, 4934 sizeof(int), 0644, proc_dointvec_minmax, false); 4935 set_table_entry(&table[10], "flags", &sd->flags, 4936 sizeof(int), 0644, proc_dointvec_minmax, false); 4937 set_table_entry(&table[11], "name", sd->name, 4938 CORENAME_MAX_SIZE, 0444, proc_dostring, false); 4939 /* &table[12] is terminator */ 4940 4941 return table; 4942} 4943 4944static ctl_table *sd_alloc_ctl_cpu_table(int cpu) 4945{ 4946 struct ctl_table *entry, *table; 4947 struct sched_domain *sd; 4948 int domain_num = 0, i; 4949 char buf[32]; 4950 4951 for_each_domain(cpu, sd) 4952 domain_num++; 4953 entry = table = sd_alloc_ctl_entry(domain_num + 1); 4954 if (table == NULL) 4955 return NULL; 4956 4957 i = 0; 4958 for_each_domain(cpu, sd) { 4959 snprintf(buf, 32, "domain%d", i); 4960 entry->procname = kstrdup(buf, GFP_KERNEL); 4961 entry->mode = 0555; 4962 entry->child = sd_alloc_ctl_domain_table(sd); 4963 entry++; 4964 i++; 4965 } 4966 return table; 4967} 4968 4969static struct ctl_table_header *sd_sysctl_header; 4970static void register_sched_domain_sysctl(void) 4971{ 4972 int i, cpu_num = num_possible_cpus(); 4973 struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1); 4974 char buf[32]; 4975 4976 WARN_ON(sd_ctl_dir[0].child); 4977 sd_ctl_dir[0].child = entry; 4978 4979 if (entry == NULL) 4980 return; 4981 4982 for_each_possible_cpu(i) { 4983 snprintf(buf, 32, "cpu%d", i); 4984 entry->procname = kstrdup(buf, GFP_KERNEL); 4985 entry->mode = 0555; 4986 entry->child = sd_alloc_ctl_cpu_table(i); 4987 entry++; 4988 } 4989 4990 WARN_ON(sd_sysctl_header); 4991 sd_sysctl_header = register_sysctl_table(sd_ctl_root); 4992} 4993 4994/* may be called multiple times per register */ 4995static void unregister_sched_domain_sysctl(void) 4996{ 4997 if (sd_sysctl_header) 4998 unregister_sysctl_table(sd_sysctl_header); 4999 sd_sysctl_header = NULL; 5000 if (sd_ctl_dir[0].child) 5001 sd_free_ctl_entry(&sd_ctl_dir[0].child); 5002} 5003#else 5004static void register_sched_domain_sysctl(void) 5005{ 5006} 5007static void unregister_sched_domain_sysctl(void) 5008{ 5009} 5010#endif 5011 5012static void set_rq_online(struct rq *rq) 5013{ 5014 if (!rq->online) { 5015 const struct sched_class *class; 5016 5017 cpumask_set_cpu(rq->cpu, rq->rd->online); 5018 rq->online = 1; 5019 5020 for_each_class(class) { 5021 if (class->rq_online) 5022 class->rq_online(rq); 5023 } 5024 } 5025} 5026 5027static void set_rq_offline(struct rq *rq) 5028{ 5029 if (rq->online) { 5030 const struct sched_class *class; 5031 5032 for_each_class(class) { 5033 if (class->rq_offline) 5034 class->rq_offline(rq); 5035 } 5036 5037 cpumask_clear_cpu(rq->cpu, rq->rd->online); 5038 rq->online = 0; 5039 } 5040} 5041 5042/* 5043 * migration_call - callback that gets triggered when a CPU is added. 5044 * Here we can start up the necessary migration thread for the new CPU. 5045 */ 5046static int __cpuinit 5047migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) 5048{ 5049 int cpu = (long)hcpu; 5050 unsigned long flags; 5051 struct rq *rq = cpu_rq(cpu); 5052 5053 switch (action & ~CPU_TASKS_FROZEN) { 5054 5055 case CPU_UP_PREPARE: 5056 rq->calc_load_update = calc_load_update; 5057 break; 5058 5059 case CPU_ONLINE: 5060 /* Update our root-domain */ 5061 raw_spin_lock_irqsave(&rq->lock, flags); 5062 if (rq->rd) { 5063 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); 5064 5065 set_rq_online(rq); 5066 } 5067 raw_spin_unlock_irqrestore(&rq->lock, flags); 5068 break; 5069 5070#ifdef CONFIG_HOTPLUG_CPU 5071 case CPU_DYING: 5072 sched_ttwu_pending(); 5073 /* Update our root-domain */ 5074 raw_spin_lock_irqsave(&rq->lock, flags); 5075 if (rq->rd) { 5076 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); 5077 set_rq_offline(rq); 5078 } 5079 migrate_tasks(cpu); 5080 BUG_ON(rq->nr_running != 1); /* the migration thread */ 5081 raw_spin_unlock_irqrestore(&rq->lock, flags); 5082 break; 5083 5084 case CPU_DEAD: 5085 calc_load_migrate(rq); 5086 break; 5087#endif 5088 } 5089 5090 update_max_interval(); 5091 5092 return NOTIFY_OK; 5093} 5094 5095/* 5096 * Register at high priority so that task migration (migrate_all_tasks) 5097 * happens before everything else. This has to be lower priority than 5098 * the notifier in the perf_event subsystem, though. 5099 */ 5100static struct notifier_block __cpuinitdata migration_notifier = { 5101 .notifier_call = migration_call, 5102 .priority = CPU_PRI_MIGRATION, 5103}; 5104 5105static int __cpuinit sched_cpu_active(struct notifier_block *nfb, 5106 unsigned long action, void *hcpu) 5107{ 5108 switch (action & ~CPU_TASKS_FROZEN) { 5109 case CPU_STARTING: 5110 case CPU_DOWN_FAILED: 5111 set_cpu_active((long)hcpu, true); 5112 return NOTIFY_OK; 5113 default: 5114 return NOTIFY_DONE; 5115 } 5116} 5117 5118static int __cpuinit sched_cpu_inactive(struct notifier_block *nfb, 5119 unsigned long action, void *hcpu) 5120{ 5121 switch (action & ~CPU_TASKS_FROZEN) { 5122 case CPU_DOWN_PREPARE: 5123 set_cpu_active((long)hcpu, false); 5124 return NOTIFY_OK; 5125 default: 5126 return NOTIFY_DONE; 5127 } 5128} 5129 5130static int __init migration_init(void) 5131{ 5132 void *cpu = (void *)(long)smp_processor_id(); 5133 int err; 5134 5135 /* Initialize migration for the boot CPU */ 5136 err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); 5137 BUG_ON(err == NOTIFY_BAD); 5138 migration_call(&migration_notifier, CPU_ONLINE, cpu); 5139 register_cpu_notifier(&migration_notifier); 5140 5141 /* Register cpu active notifiers */ 5142 cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE); 5143 cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE); 5144 5145 return 0; 5146} 5147early_initcall(migration_init); 5148#endif 5149 5150#ifdef CONFIG_SMP 5151 5152static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */ 5153 5154#ifdef CONFIG_SCHED_DEBUG 5155 5156static __read_mostly int sched_debug_enabled; 5157 5158static int __init sched_debug_setup(char *str) 5159{ 5160 sched_debug_enabled = 1; 5161 5162 return 0; 5163} 5164early_param("sched_debug", sched_debug_setup); 5165 5166static inline bool sched_debug(void) 5167{ 5168 return sched_debug_enabled; 5169} 5170 5171static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, 5172 struct cpumask *groupmask) 5173{ 5174 struct sched_group *group = sd->groups; 5175 char str[256]; 5176 5177 cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd)); 5178 cpumask_clear(groupmask); 5179 5180 printk(KERN_DEBUG "%*s domain %d: ", level, "", level); 5181 5182 if (!(sd->flags & SD_LOAD_BALANCE)) { 5183 printk("does not load-balance\n"); 5184 if (sd->parent) 5185 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain" 5186 " has parent"); 5187 return -1; 5188 } 5189 5190 printk(KERN_CONT "span %s level %s\n", str, sd->name); 5191 5192 if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) { 5193 printk(KERN_ERR "ERROR: domain->span does not contain " 5194 "CPU%d\n", cpu); 5195 } 5196 if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) { 5197 printk(KERN_ERR "ERROR: domain->groups does not contain" 5198 " CPU%d\n", cpu); 5199 } 5200 5201 printk(KERN_DEBUG "%*s groups:", level + 1, ""); 5202 do { 5203 if (!group) { 5204 printk("\n"); 5205 printk(KERN_ERR "ERROR: group is NULL\n"); 5206 break; 5207 } 5208 5209 /* 5210 * Even though we initialize ->power to something semi-sane, 5211 * we leave power_orig unset. This allows us to detect if 5212 * domain iteration is still funny without causing /0 traps. 5213 */ 5214 if (!group->sgp->power_orig) { 5215 printk(KERN_CONT "\n"); 5216 printk(KERN_ERR "ERROR: domain->cpu_power not " 5217 "set\n"); 5218 break; 5219 } 5220 5221 if (!cpumask_weight(sched_group_cpus(group))) { 5222 printk(KERN_CONT "\n"); 5223 printk(KERN_ERR "ERROR: empty group\n"); 5224 break; 5225 } 5226 5227 if (!(sd->flags & SD_OVERLAP) && 5228 cpumask_intersects(groupmask, sched_group_cpus(group))) { 5229 printk(KERN_CONT "\n"); 5230 printk(KERN_ERR "ERROR: repeated CPUs\n"); 5231 break; 5232 } 5233 5234 cpumask_or(groupmask, groupmask, sched_group_cpus(group)); 5235 5236 cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group)); 5237 5238 printk(KERN_CONT " %s", str); 5239 if (group->sgp->power != SCHED_POWER_SCALE) { 5240 printk(KERN_CONT " (cpu_power = %d)", 5241 group->sgp->power); 5242 } 5243 5244 group = group->next; 5245 } while (group != sd->groups); 5246 printk(KERN_CONT "\n"); 5247 5248 if (!cpumask_equal(sched_domain_span(sd), groupmask)) 5249 printk(KERN_ERR "ERROR: groups don't span domain->span\n"); 5250 5251 if (sd->parent && 5252 !cpumask_subset(groupmask, sched_domain_span(sd->parent))) 5253 printk(KERN_ERR "ERROR: parent span is not a superset " 5254 "of domain->span\n"); 5255 return 0; 5256} 5257 5258static void sched_domain_debug(struct sched_domain *sd, int cpu) 5259{ 5260 int level = 0; 5261 5262 if (!sched_debug_enabled) 5263 return; 5264 5265 if (!sd) { 5266 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); 5267 return; 5268 } 5269 5270 printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); 5271 5272 for (;;) { 5273 if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask)) 5274 break; 5275 level++; 5276 sd = sd->parent; 5277 if (!sd) 5278 break; 5279 } 5280} 5281#else /* !CONFIG_SCHED_DEBUG */ 5282# define sched_domain_debug(sd, cpu) do { } while (0) 5283static inline bool sched_debug(void) 5284{ 5285 return false; 5286} 5287#endif /* CONFIG_SCHED_DEBUG */ 5288 5289static int sd_degenerate(struct sched_domain *sd) 5290{ 5291 if (cpumask_weight(sched_domain_span(sd)) == 1) 5292 return 1; 5293 5294 /* Following flags need at least 2 groups */ 5295 if (sd->flags & (SD_LOAD_BALANCE | 5296 SD_BALANCE_NEWIDLE | 5297 SD_BALANCE_FORK | 5298 SD_BALANCE_EXEC | 5299 SD_SHARE_CPUPOWER | 5300 SD_SHARE_PKG_RESOURCES)) { 5301 if (sd->groups != sd->groups->next) 5302 return 0; 5303 } 5304 5305 /* Following flags don't use groups */ 5306 if (sd->flags & (SD_WAKE_AFFINE)) 5307 return 0; 5308 5309 return 1; 5310} 5311 5312static int 5313sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) 5314{ 5315 unsigned long cflags = sd->flags, pflags = parent->flags; 5316 5317 if (sd_degenerate(parent)) 5318 return 1; 5319 5320 if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent))) 5321 return 0; 5322 5323 /* Flags needing groups don't count if only 1 group in parent */ 5324 if (parent->groups == parent->groups->next) { 5325 pflags &= ~(SD_LOAD_BALANCE | 5326 SD_BALANCE_NEWIDLE | 5327 SD_BALANCE_FORK | 5328 SD_BALANCE_EXEC | 5329 SD_SHARE_CPUPOWER | 5330 SD_SHARE_PKG_RESOURCES); 5331 if (nr_node_ids == 1) 5332 pflags &= ~SD_SERIALIZE; 5333 } 5334 if (~cflags & pflags) 5335 return 0; 5336 5337 return 1; 5338} 5339 5340static void free_rootdomain(struct rcu_head *rcu) 5341{ 5342 struct root_domain *rd = container_of(rcu, struct root_domain, rcu); 5343 5344 cpupri_cleanup(&rd->cpupri); 5345 free_cpumask_var(rd->rto_mask); 5346 free_cpumask_var(rd->online); 5347 free_cpumask_var(rd->span); 5348 kfree(rd); 5349} 5350 5351static void rq_attach_root(struct rq *rq, struct root_domain *rd) 5352{ 5353 struct root_domain *old_rd = NULL; 5354 unsigned long flags; 5355 5356 raw_spin_lock_irqsave(&rq->lock, flags); 5357 5358 if (rq->rd) { 5359 old_rd = rq->rd; 5360 5361 if (cpumask_test_cpu(rq->cpu, old_rd->online)) 5362 set_rq_offline(rq); 5363 5364 cpumask_clear_cpu(rq->cpu, old_rd->span); 5365 5366 /* 5367 * If we dont want to free the old_rt yet then 5368 * set old_rd to NULL to skip the freeing later 5369 * in this function: 5370 */ 5371 if (!atomic_dec_and_test(&old_rd->refcount)) 5372 old_rd = NULL; 5373 } 5374 5375 atomic_inc(&rd->refcount); 5376 rq->rd = rd; 5377 5378 cpumask_set_cpu(rq->cpu, rd->span); 5379 if (cpumask_test_cpu(rq->cpu, cpu_active_mask)) 5380 set_rq_online(rq); 5381 5382 raw_spin_unlock_irqrestore(&rq->lock, flags); 5383 5384 if (old_rd) 5385 call_rcu_sched(&old_rd->rcu, free_rootdomain); 5386} 5387 5388static int init_rootdomain(struct root_domain *rd) 5389{ 5390 memset(rd, 0, sizeof(*rd)); 5391 5392 if (!alloc_cpumask_var(&rd->span, GFP_KERNEL)) 5393 goto out; 5394 if (!alloc_cpumask_var(&rd->online, GFP_KERNEL)) 5395 goto free_span; 5396 if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL)) 5397 goto free_online; 5398 5399 if (cpupri_init(&rd->cpupri) != 0) 5400 goto free_rto_mask; 5401 return 0; 5402 5403free_rto_mask: 5404 free_cpumask_var(rd->rto_mask); 5405free_online: 5406 free_cpumask_var(rd->online); 5407free_span: 5408 free_cpumask_var(rd->span); 5409out: 5410 return -ENOMEM; 5411} 5412 5413/* 5414 * By default the system creates a single root-domain with all cpus as 5415 * members (mimicking the global state we have today). 5416 */ 5417struct root_domain def_root_domain; 5418 5419static void init_defrootdomain(void) 5420{ 5421 init_rootdomain(&def_root_domain); 5422 5423 atomic_set(&def_root_domain.refcount, 1); 5424} 5425 5426static struct root_domain *alloc_rootdomain(void) 5427{ 5428 struct root_domain *rd; 5429 5430 rd = kmalloc(sizeof(*rd), GFP_KERNEL); 5431 if (!rd) 5432 return NULL; 5433 5434 if (init_rootdomain(rd) != 0) { 5435 kfree(rd); 5436 return NULL; 5437 } 5438 5439 return rd; 5440} 5441 5442static void free_sched_groups(struct sched_group *sg, int free_sgp) 5443{ 5444 struct sched_group *tmp, *first; 5445 5446 if (!sg) 5447 return; 5448 5449 first = sg; 5450 do { 5451 tmp = sg->next; 5452 5453 if (free_sgp && atomic_dec_and_test(&sg->sgp->ref)) 5454 kfree(sg->sgp); 5455 5456 kfree(sg); 5457 sg = tmp; 5458 } while (sg != first); 5459} 5460 5461static void free_sched_domain(struct rcu_head *rcu) 5462{ 5463 struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu); 5464 5465 /* 5466 * If its an overlapping domain it has private groups, iterate and 5467 * nuke them all. 5468 */ 5469 if (sd->flags & SD_OVERLAP) { 5470 free_sched_groups(sd->groups, 1); 5471 } else if (atomic_dec_and_test(&sd->groups->ref)) { 5472 kfree(sd->groups->sgp); 5473 kfree(sd->groups); 5474 } 5475 kfree(sd); 5476} 5477 5478static void destroy_sched_domain(struct sched_domain *sd, int cpu) 5479{ 5480 call_rcu(&sd->rcu, free_sched_domain); 5481} 5482 5483static void destroy_sched_domains(struct sched_domain *sd, int cpu) 5484{ 5485 for (; sd; sd = sd->parent) 5486 destroy_sched_domain(sd, cpu); 5487} 5488 5489/* 5490 * Keep a special pointer to the highest sched_domain that has 5491 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this 5492 * allows us to avoid some pointer chasing select_idle_sibling(). 5493 * 5494 * Also keep a unique ID per domain (we use the first cpu number in 5495 * the cpumask of the domain), this allows us to quickly tell if 5496 * two cpus are in the same cache domain, see cpus_share_cache(). 5497 */ 5498DEFINE_PER_CPU(struct sched_domain *, sd_llc); 5499DEFINE_PER_CPU(int, sd_llc_id); 5500 5501static void update_top_cache_domain(int cpu) 5502{ 5503 struct sched_domain *sd; 5504 int id = cpu; 5505 5506 sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES); 5507 if (sd) 5508 id = cpumask_first(sched_domain_span(sd)); 5509 5510 rcu_assign_pointer(per_cpu(sd_llc, cpu), sd); 5511 per_cpu(sd_llc_id, cpu) = id; 5512} 5513 5514/* 5515 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must 5516 * hold the hotplug lock. 5517 */ 5518static void 5519cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) 5520{ 5521 struct rq *rq = cpu_rq(cpu); 5522 struct sched_domain *tmp; 5523 5524 /* Remove the sched domains which do not contribute to scheduling. */ 5525 for (tmp = sd; tmp; ) { 5526 struct sched_domain *parent = tmp->parent; 5527 if (!parent) 5528 break; 5529 5530 if (sd_parent_degenerate(tmp, parent)) { 5531 tmp->parent = parent->parent; 5532 if (parent->parent) 5533 parent->parent->child = tmp; 5534 destroy_sched_domain(parent, cpu); 5535 } else 5536 tmp = tmp->parent; 5537 } 5538 5539 if (sd && sd_degenerate(sd)) { 5540 tmp = sd; 5541 sd = sd->parent; 5542 destroy_sched_domain(tmp, cpu); 5543 if (sd) 5544 sd->child = NULL; 5545 } 5546 5547 sched_domain_debug(sd, cpu); 5548 5549 rq_attach_root(rq, rd); 5550 tmp = rq->sd; 5551 rcu_assign_pointer(rq->sd, sd); 5552 destroy_sched_domains(tmp, cpu); 5553 5554 update_top_cache_domain(cpu); 5555} 5556 5557/* cpus with isolated domains */ 5558static cpumask_var_t cpu_isolated_map; 5559 5560/* Setup the mask of cpus configured for isolated domains */ 5561static int __init isolated_cpu_setup(char *str) 5562{ 5563 alloc_bootmem_cpumask_var(&cpu_isolated_map); 5564 cpulist_parse(str, cpu_isolated_map); 5565 return 1; 5566} 5567 5568__setup("isolcpus=", isolated_cpu_setup); 5569 5570static const struct cpumask *cpu_cpu_mask(int cpu) 5571{ 5572 return cpumask_of_node(cpu_to_node(cpu)); 5573} 5574 5575struct sd_data { 5576 struct sched_domain **__percpu sd; 5577 struct sched_group **__percpu sg; 5578 struct sched_group_power **__percpu sgp; 5579}; 5580 5581struct s_data { 5582 struct sched_domain ** __percpu sd; 5583 struct root_domain *rd; 5584}; 5585 5586enum s_alloc { 5587 sa_rootdomain, 5588 sa_sd, 5589 sa_sd_storage, 5590 sa_none, 5591}; 5592 5593struct sched_domain_topology_level; 5594 5595typedef struct sched_domain *(*sched_domain_init_f)(struct sched_domain_topology_level *tl, int cpu); 5596typedef const struct cpumask *(*sched_domain_mask_f)(int cpu); 5597 5598#define SDTL_OVERLAP 0x01 5599 5600struct sched_domain_topology_level { 5601 sched_domain_init_f init; 5602 sched_domain_mask_f mask; 5603 int flags; 5604 int numa_level; 5605 struct sd_data data; 5606}; 5607 5608/* 5609 * Build an iteration mask that can exclude certain CPUs from the upwards 5610 * domain traversal. 5611 * 5612 * Asymmetric node setups can result in situations where the domain tree is of 5613 * unequal depth, make sure to skip domains that already cover the entire 5614 * range. 5615 * 5616 * In that case build_sched_domains() will have terminated the iteration early 5617 * and our sibling sd spans will be empty. Domains should always include the 5618 * cpu they're built on, so check that. 5619 * 5620 */ 5621static void build_group_mask(struct sched_domain *sd, struct sched_group *sg) 5622{ 5623 const struct cpumask *span = sched_domain_span(sd); 5624 struct sd_data *sdd = sd->private; 5625 struct sched_domain *sibling; 5626 int i; 5627 5628 for_each_cpu(i, span) { 5629 sibling = *per_cpu_ptr(sdd->sd, i); 5630 if (!cpumask_test_cpu(i, sched_domain_span(sibling))) 5631 continue; 5632 5633 cpumask_set_cpu(i, sched_group_mask(sg)); 5634 } 5635} 5636 5637/* 5638 * Return the canonical balance cpu for this group, this is the first cpu 5639 * of this group that's also in the iteration mask. 5640 */ 5641int group_balance_cpu(struct sched_group *sg) 5642{ 5643 return cpumask_first_and(sched_group_cpus(sg), sched_group_mask(sg)); 5644} 5645 5646static int 5647build_overlap_sched_groups(struct sched_domain *sd, int cpu) 5648{ 5649 struct sched_group *first = NULL, *last = NULL, *groups = NULL, *sg; 5650 const struct cpumask *span = sched_domain_span(sd); 5651 struct cpumask *covered = sched_domains_tmpmask; 5652 struct sd_data *sdd = sd->private; 5653 struct sched_domain *child; 5654 int i; 5655 5656 cpumask_clear(covered); 5657 5658 for_each_cpu(i, span) { 5659 struct cpumask *sg_span; 5660 5661 if (cpumask_test_cpu(i, covered)) 5662 continue; 5663 5664 child = *per_cpu_ptr(sdd->sd, i); 5665 5666 /* See the comment near build_group_mask(). */ 5667 if (!cpumask_test_cpu(i, sched_domain_span(child))) 5668 continue; 5669 5670 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), 5671 GFP_KERNEL, cpu_to_node(cpu)); 5672 5673 if (!sg) 5674 goto fail; 5675 5676 sg_span = sched_group_cpus(sg); 5677 if (child->child) { 5678 child = child->child; 5679 cpumask_copy(sg_span, sched_domain_span(child)); 5680 } else 5681 cpumask_set_cpu(i, sg_span); 5682 5683 cpumask_or(covered, covered, sg_span); 5684 5685 sg->sgp = *per_cpu_ptr(sdd->sgp, i); 5686 if (atomic_inc_return(&sg->sgp->ref) == 1) 5687 build_group_mask(sd, sg); 5688 5689 /* 5690 * Initialize sgp->power such that even if we mess up the 5691 * domains and no possible iteration will get us here, we won't 5692 * die on a /0 trap. 5693 */ 5694 sg->sgp->power = SCHED_POWER_SCALE * cpumask_weight(sg_span); 5695 5696 /* 5697 * Make sure the first group of this domain contains the 5698 * canonical balance cpu. Otherwise the sched_domain iteration 5699 * breaks. See update_sg_lb_stats(). 5700 */ 5701 if ((!groups && cpumask_test_cpu(cpu, sg_span)) || 5702 group_balance_cpu(sg) == cpu) 5703 groups = sg; 5704 5705 if (!first) 5706 first = sg; 5707 if (last) 5708 last->next = sg; 5709 last = sg; 5710 last->next = first; 5711 } 5712 sd->groups = groups; 5713 5714 return 0; 5715 5716fail: 5717 free_sched_groups(first, 0); 5718 5719 return -ENOMEM; 5720} 5721 5722static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg) 5723{ 5724 struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu); 5725 struct sched_domain *child = sd->child; 5726 5727 if (child) 5728 cpu = cpumask_first(sched_domain_span(child)); 5729 5730 if (sg) { 5731 *sg = *per_cpu_ptr(sdd->sg, cpu); 5732 (*sg)->sgp = *per_cpu_ptr(sdd->sgp, cpu); 5733 atomic_set(&(*sg)->sgp->ref, 1); /* for claim_allocations */ 5734 } 5735 5736 return cpu; 5737} 5738 5739/* 5740 * build_sched_groups will build a circular linked list of the groups 5741 * covered by the given span, and will set each group's ->cpumask correctly, 5742 * and ->cpu_power to 0. 5743 * 5744 * Assumes the sched_domain tree is fully constructed 5745 */ 5746static int 5747build_sched_groups(struct sched_domain *sd, int cpu) 5748{ 5749 struct sched_group *first = NULL, *last = NULL; 5750 struct sd_data *sdd = sd->private; 5751 const struct cpumask *span = sched_domain_span(sd); 5752 struct cpumask *covered; 5753 int i; 5754 5755 get_group(cpu, sdd, &sd->groups); 5756 atomic_inc(&sd->groups->ref); 5757 5758 if (cpu != cpumask_first(sched_domain_span(sd))) 5759 return 0; 5760 5761 lockdep_assert_held(&sched_domains_mutex); 5762 covered = sched_domains_tmpmask; 5763 5764 cpumask_clear(covered); 5765 5766 for_each_cpu(i, span) { 5767 struct sched_group *sg; 5768 int group = get_group(i, sdd, &sg); 5769 int j; 5770 5771 if (cpumask_test_cpu(i, covered)) 5772 continue; 5773 5774 cpumask_clear(sched_group_cpus(sg)); 5775 sg->sgp->power = 0; 5776 cpumask_setall(sched_group_mask(sg)); 5777 5778 for_each_cpu(j, span) { 5779 if (get_group(j, sdd, NULL) != group) 5780 continue; 5781 5782 cpumask_set_cpu(j, covered); 5783 cpumask_set_cpu(j, sched_group_cpus(sg)); 5784 } 5785 5786 if (!first) 5787 first = sg; 5788 if (last) 5789 last->next = sg; 5790 last = sg; 5791 } 5792 last->next = first; 5793 5794 return 0; 5795} 5796 5797/* 5798 * Initialize sched groups cpu_power. 5799 * 5800 * cpu_power indicates the capacity of sched group, which is used while 5801 * distributing the load between different sched groups in a sched domain. 5802 * Typically cpu_power for all the groups in a sched domain will be same unless 5803 * there are asymmetries in the topology. If there are asymmetries, group 5804 * having more cpu_power will pickup more load compared to the group having 5805 * less cpu_power. 5806 */ 5807static void init_sched_groups_power(int cpu, struct sched_domain *sd) 5808{ 5809 struct sched_group *sg = sd->groups; 5810 5811 WARN_ON(!sd || !sg); 5812 5813 do { 5814 sg->group_weight = cpumask_weight(sched_group_cpus(sg)); 5815 sg = sg->next; 5816 } while (sg != sd->groups); 5817 5818 if (cpu != group_balance_cpu(sg)) 5819 return; 5820 5821 update_group_power(sd, cpu); 5822 atomic_set(&sg->sgp->nr_busy_cpus, sg->group_weight); 5823} 5824 5825int __weak arch_sd_sibling_asym_packing(void) 5826{ 5827 return 0*SD_ASYM_PACKING; 5828} 5829 5830/* 5831 * Initializers for schedule domains 5832 * Non-inlined to reduce accumulated stack pressure in build_sched_domains() 5833 */ 5834 5835#ifdef CONFIG_SCHED_DEBUG 5836# define SD_INIT_NAME(sd, type) sd->name = #type 5837#else 5838# define SD_INIT_NAME(sd, type) do { } while (0) 5839#endif 5840 5841#define SD_INIT_FUNC(type) \ 5842static noinline struct sched_domain * \ 5843sd_init_##type(struct sched_domain_topology_level *tl, int cpu) \ 5844{ \ 5845 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); \ 5846 *sd = SD_##type##_INIT; \ 5847 SD_INIT_NAME(sd, type); \ 5848 sd->private = &tl->data; \ 5849 return sd; \ 5850} 5851 5852SD_INIT_FUNC(CPU) 5853#ifdef CONFIG_SCHED_SMT 5854 SD_INIT_FUNC(SIBLING) 5855#endif 5856#ifdef CONFIG_SCHED_MC 5857 SD_INIT_FUNC(MC) 5858#endif 5859#ifdef CONFIG_SCHED_BOOK 5860 SD_INIT_FUNC(BOOK) 5861#endif 5862 5863static int default_relax_domain_level = -1; 5864int sched_domain_level_max; 5865 5866static int __init setup_relax_domain_level(char *str) 5867{ 5868 if (kstrtoint(str, 0, &default_relax_domain_level)) 5869 pr_warn("Unable to set relax_domain_level\n"); 5870 5871 return 1; 5872} 5873__setup("relax_domain_level=", setup_relax_domain_level); 5874 5875static void set_domain_attribute(struct sched_domain *sd, 5876 struct sched_domain_attr *attr) 5877{ 5878 int request; 5879 5880 if (!attr || attr->relax_domain_level < 0) { 5881 if (default_relax_domain_level < 0) 5882 return; 5883 else 5884 request = default_relax_domain_level; 5885 } else 5886 request = attr->relax_domain_level; 5887 if (request < sd->level) { 5888 /* turn off idle balance on this domain */ 5889 sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); 5890 } else { 5891 /* turn on idle balance on this domain */ 5892 sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); 5893 } 5894} 5895 5896static void __sdt_free(const struct cpumask *cpu_map); 5897static int __sdt_alloc(const struct cpumask *cpu_map); 5898 5899static void __free_domain_allocs(struct s_data *d, enum s_alloc what, 5900 const struct cpumask *cpu_map) 5901{ 5902 switch (what) { 5903 case sa_rootdomain: 5904 if (!atomic_read(&d->rd->refcount)) 5905 free_rootdomain(&d->rd->rcu); /* fall through */ 5906 case sa_sd: 5907 free_percpu(d->sd); /* fall through */ 5908 case sa_sd_storage: 5909 __sdt_free(cpu_map); /* fall through */ 5910 case sa_none: 5911 break; 5912 } 5913} 5914 5915static enum s_alloc __visit_domain_allocation_hell(struct s_data *d, 5916 const struct cpumask *cpu_map) 5917{ 5918 memset(d, 0, sizeof(*d)); 5919 5920 if (__sdt_alloc(cpu_map)) 5921 return sa_sd_storage; 5922 d->sd = alloc_percpu(struct sched_domain *); 5923 if (!d->sd) 5924 return sa_sd_storage; 5925 d->rd = alloc_rootdomain(); 5926 if (!d->rd) 5927 return sa_sd; 5928 return sa_rootdomain; 5929} 5930 5931/* 5932 * NULL the sd_data elements we've used to build the sched_domain and 5933 * sched_group structure so that the subsequent __free_domain_allocs() 5934 * will not free the data we're using. 5935 */ 5936static void claim_allocations(int cpu, struct sched_domain *sd) 5937{ 5938 struct sd_data *sdd = sd->private; 5939 5940 WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd); 5941 *per_cpu_ptr(sdd->sd, cpu) = NULL; 5942 5943 if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref)) 5944 *per_cpu_ptr(sdd->sg, cpu) = NULL; 5945 5946 if (atomic_read(&(*per_cpu_ptr(sdd->sgp, cpu))->ref)) 5947 *per_cpu_ptr(sdd->sgp, cpu) = NULL; 5948} 5949 5950#ifdef CONFIG_SCHED_SMT 5951static const struct cpumask *cpu_smt_mask(int cpu) 5952{ 5953 return topology_thread_cpumask(cpu); 5954} 5955#endif 5956 5957/* 5958 * Topology list, bottom-up. 5959 */ 5960static struct sched_domain_topology_level default_topology[] = { 5961#ifdef CONFIG_SCHED_SMT 5962 { sd_init_SIBLING, cpu_smt_mask, }, 5963#endif 5964#ifdef CONFIG_SCHED_MC 5965 { sd_init_MC, cpu_coregroup_mask, }, 5966#endif 5967#ifdef CONFIG_SCHED_BOOK 5968 { sd_init_BOOK, cpu_book_mask, }, 5969#endif 5970 { sd_init_CPU, cpu_cpu_mask, }, 5971 { NULL, }, 5972}; 5973 5974static struct sched_domain_topology_level *sched_domain_topology = default_topology; 5975 5976#ifdef CONFIG_NUMA 5977 5978static int sched_domains_numa_levels; 5979static int *sched_domains_numa_distance; 5980static struct cpumask ***sched_domains_numa_masks; 5981static int sched_domains_curr_level; 5982 5983static inline int sd_local_flags(int level) 5984{ 5985 if (sched_domains_numa_distance[level] > RECLAIM_DISTANCE) 5986 return 0; 5987 5988 return SD_BALANCE_EXEC | SD_BALANCE_FORK | SD_WAKE_AFFINE; 5989} 5990 5991static struct sched_domain * 5992sd_numa_init(struct sched_domain_topology_level *tl, int cpu) 5993{ 5994 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); 5995 int level = tl->numa_level; 5996 int sd_weight = cpumask_weight( 5997 sched_domains_numa_masks[level][cpu_to_node(cpu)]); 5998 5999 *sd = (struct sched_domain){ 6000 .min_interval = sd_weight, 6001 .max_interval = 2*sd_weight, 6002 .busy_factor = 32, 6003 .imbalance_pct = 125, 6004 .cache_nice_tries = 2, 6005 .busy_idx = 3, 6006 .idle_idx = 2, 6007 .newidle_idx = 0, 6008 .wake_idx = 0, 6009 .forkexec_idx = 0, 6010 6011 .flags = 1*SD_LOAD_BALANCE 6012 | 1*SD_BALANCE_NEWIDLE 6013 | 0*SD_BALANCE_EXEC 6014 | 0*SD_BALANCE_FORK 6015 | 0*SD_BALANCE_WAKE 6016 | 0*SD_WAKE_AFFINE 6017 | 0*SD_SHARE_CPUPOWER 6018 | 0*SD_SHARE_PKG_RESOURCES 6019 | 1*SD_SERIALIZE 6020 | 0*SD_PREFER_SIBLING 6021 | sd_local_flags(level) 6022 , 6023 .last_balance = jiffies, 6024 .balance_interval = sd_weight, 6025 }; 6026 SD_INIT_NAME(sd, NUMA); 6027 sd->private = &tl->data; 6028 6029 /* 6030 * Ugly hack to pass state to sd_numa_mask()... 6031 */ 6032 sched_domains_curr_level = tl->numa_level; 6033 6034 return sd; 6035} 6036 6037static const struct cpumask *sd_numa_mask(int cpu) 6038{ 6039 return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)]; 6040} 6041 6042static void sched_numa_warn(const char *str) 6043{ 6044 static int done = false; 6045 int i,j; 6046 6047 if (done) 6048 return; 6049 6050 done = true; 6051 6052 printk(KERN_WARNING "ERROR: %s\n\n", str); 6053 6054 for (i = 0; i < nr_node_ids; i++) { 6055 printk(KERN_WARNING " "); 6056 for (j = 0; j < nr_node_ids; j++) 6057 printk(KERN_CONT "%02d ", node_distance(i,j)); 6058 printk(KERN_CONT "\n"); 6059 } 6060 printk(KERN_WARNING "\n"); 6061} 6062 6063static bool find_numa_distance(int distance) 6064{ 6065 int i; 6066 6067 if (distance == node_distance(0, 0)) 6068 return true; 6069 6070 for (i = 0; i < sched_domains_numa_levels; i++) { 6071 if (sched_domains_numa_distance[i] == distance) 6072 return true; 6073 } 6074 6075 return false; 6076} 6077 6078static void sched_init_numa(void) 6079{ 6080 int next_distance, curr_distance = node_distance(0, 0); 6081 struct sched_domain_topology_level *tl; 6082 int level = 0; 6083 int i, j, k; 6084 6085 sched_domains_numa_distance = kzalloc(sizeof(int) * nr_node_ids, GFP_KERNEL); 6086 if (!sched_domains_numa_distance) 6087 return; 6088 6089 /* 6090 * O(nr_nodes^2) deduplicating selection sort -- in order to find the 6091 * unique distances in the node_distance() table. 6092 * 6093 * Assumes node_distance(0,j) includes all distances in 6094 * node_distance(i,j) in order to avoid cubic time. 6095 */ 6096 next_distance = curr_distance; 6097 for (i = 0; i < nr_node_ids; i++) { 6098 for (j = 0; j < nr_node_ids; j++) { 6099 for (k = 0; k < nr_node_ids; k++) { 6100 int distance = node_distance(i, k); 6101 6102 if (distance > curr_distance && 6103 (distance < next_distance || 6104 next_distance == curr_distance)) 6105 next_distance = distance; 6106 6107 /* 6108 * While not a strong assumption it would be nice to know 6109 * about cases where if node A is connected to B, B is not 6110 * equally connected to A. 6111 */ 6112 if (sched_debug() && node_distance(k, i) != distance) 6113 sched_numa_warn("Node-distance not symmetric"); 6114 6115 if (sched_debug() && i && !find_numa_distance(distance)) 6116 sched_numa_warn("Node-0 not representative"); 6117 } 6118 if (next_distance != curr_distance) { 6119 sched_domains_numa_distance[level++] = next_distance; 6120 sched_domains_numa_levels = level; 6121 curr_distance = next_distance; 6122 } else break; 6123 } 6124 6125 /* 6126 * In case of sched_debug() we verify the above assumption. 6127 */ 6128 if (!sched_debug()) 6129 break; 6130 } 6131 /* 6132 * 'level' contains the number of unique distances, excluding the 6133 * identity distance node_distance(i,i). 6134 * 6135 * The sched_domains_nume_distance[] array includes the actual distance 6136 * numbers. 6137 */ 6138 6139 /* 6140 * Here, we should temporarily reset sched_domains_numa_levels to 0. 6141 * If it fails to allocate memory for array sched_domains_numa_masks[][], 6142 * the array will contain less then 'level' members. This could be 6143 * dangerous when we use it to iterate array sched_domains_numa_masks[][] 6144 * in other functions. 6145 * 6146 * We reset it to 'level' at the end of this function. 6147 */ 6148 sched_domains_numa_levels = 0; 6149 6150 sched_domains_numa_masks = kzalloc(sizeof(void *) * level, GFP_KERNEL); 6151 if (!sched_domains_numa_masks) 6152 return; 6153 6154 /* 6155 * Now for each level, construct a mask per node which contains all 6156 * cpus of nodes that are that many hops away from us. 6157 */ 6158 for (i = 0; i < level; i++) { 6159 sched_domains_numa_masks[i] = 6160 kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL); 6161 if (!sched_domains_numa_masks[i]) 6162 return; 6163 6164 for (j = 0; j < nr_node_ids; j++) { 6165 struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL); 6166 if (!mask) 6167 return; 6168 6169 sched_domains_numa_masks[i][j] = mask; 6170 6171 for (k = 0; k < nr_node_ids; k++) { 6172 if (node_distance(j, k) > sched_domains_numa_distance[i]) 6173 continue; 6174 6175 cpumask_or(mask, mask, cpumask_of_node(k)); 6176 } 6177 } 6178 } 6179 6180 tl = kzalloc((ARRAY_SIZE(default_topology) + level) * 6181 sizeof(struct sched_domain_topology_level), GFP_KERNEL); 6182 if (!tl) 6183 return; 6184 6185 /* 6186 * Copy the default topology bits.. 6187 */ 6188 for (i = 0; default_topology[i].init; i++) 6189 tl[i] = default_topology[i]; 6190 6191 /* 6192 * .. and append 'j' levels of NUMA goodness. 6193 */ 6194 for (j = 0; j < level; i++, j++) { 6195 tl[i] = (struct sched_domain_topology_level){ 6196 .init = sd_numa_init, 6197 .mask = sd_numa_mask, 6198 .flags = SDTL_OVERLAP, 6199 .numa_level = j, 6200 }; 6201 } 6202 6203 sched_domain_topology = tl; 6204 6205 sched_domains_numa_levels = level; 6206} 6207 6208static void sched_domains_numa_masks_set(int cpu) 6209{ 6210 int i, j; 6211 int node = cpu_to_node(cpu); 6212 6213 for (i = 0; i < sched_domains_numa_levels; i++) { 6214 for (j = 0; j < nr_node_ids; j++) { 6215 if (node_distance(j, node) <= sched_domains_numa_distance[i]) 6216 cpumask_set_cpu(cpu, sched_domains_numa_masks[i][j]); 6217 } 6218 } 6219} 6220 6221static void sched_domains_numa_masks_clear(int cpu) 6222{ 6223 int i, j; 6224 for (i = 0; i < sched_domains_numa_levels; i++) { 6225 for (j = 0; j < nr_node_ids; j++) 6226 cpumask_clear_cpu(cpu, sched_domains_numa_masks[i][j]); 6227 } 6228} 6229 6230/* 6231 * Update sched_domains_numa_masks[level][node] array when new cpus 6232 * are onlined. 6233 */ 6234static int sched_domains_numa_masks_update(struct notifier_block *nfb, 6235 unsigned long action, 6236 void *hcpu) 6237{ 6238 int cpu = (long)hcpu; 6239 6240 switch (action & ~CPU_TASKS_FROZEN) { 6241 case CPU_ONLINE: 6242 sched_domains_numa_masks_set(cpu); 6243 break; 6244 6245 case CPU_DEAD: 6246 sched_domains_numa_masks_clear(cpu); 6247 break; 6248 6249 default: 6250 return NOTIFY_DONE; 6251 } 6252 6253 return NOTIFY_OK; 6254} 6255#else 6256static inline void sched_init_numa(void) 6257{ 6258} 6259 6260static int sched_domains_numa_masks_update(struct notifier_block *nfb, 6261 unsigned long action, 6262 void *hcpu) 6263{ 6264 return 0; 6265} 6266#endif /* CONFIG_NUMA */ 6267 6268static int __sdt_alloc(const struct cpumask *cpu_map) 6269{ 6270 struct sched_domain_topology_level *tl; 6271 int j; 6272 6273 for (tl = sched_domain_topology; tl->init; tl++) { 6274 struct sd_data *sdd = &tl->data; 6275 6276 sdd->sd = alloc_percpu(struct sched_domain *); 6277 if (!sdd->sd) 6278 return -ENOMEM; 6279 6280 sdd->sg = alloc_percpu(struct sched_group *); 6281 if (!sdd->sg) 6282 return -ENOMEM; 6283 6284 sdd->sgp = alloc_percpu(struct sched_group_power *); 6285 if (!sdd->sgp) 6286 return -ENOMEM; 6287 6288 for_each_cpu(j, cpu_map) { 6289 struct sched_domain *sd; 6290 struct sched_group *sg; 6291 struct sched_group_power *sgp; 6292 6293 sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(), 6294 GFP_KERNEL, cpu_to_node(j)); 6295 if (!sd) 6296 return -ENOMEM; 6297 6298 *per_cpu_ptr(sdd->sd, j) = sd; 6299 6300 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), 6301 GFP_KERNEL, cpu_to_node(j)); 6302 if (!sg) 6303 return -ENOMEM; 6304 6305 sg->next = sg; 6306 6307 *per_cpu_ptr(sdd->sg, j) = sg; 6308 6309 sgp = kzalloc_node(sizeof(struct sched_group_power) + cpumask_size(), 6310 GFP_KERNEL, cpu_to_node(j)); 6311 if (!sgp) 6312 return -ENOMEM; 6313 6314 *per_cpu_ptr(sdd->sgp, j) = sgp; 6315 } 6316 } 6317 6318 return 0; 6319} 6320 6321static void __sdt_free(const struct cpumask *cpu_map) 6322{ 6323 struct sched_domain_topology_level *tl; 6324 int j; 6325 6326 for (tl = sched_domain_topology; tl->init; tl++) { 6327 struct sd_data *sdd = &tl->data; 6328 6329 for_each_cpu(j, cpu_map) { 6330 struct sched_domain *sd; 6331 6332 if (sdd->sd) { 6333 sd = *per_cpu_ptr(sdd->sd, j); 6334 if (sd && (sd->flags & SD_OVERLAP)) 6335 free_sched_groups(sd->groups, 0); 6336 kfree(*per_cpu_ptr(sdd->sd, j)); 6337 } 6338 6339 if (sdd->sg) 6340 kfree(*per_cpu_ptr(sdd->sg, j)); 6341 if (sdd->sgp) 6342 kfree(*per_cpu_ptr(sdd->sgp, j)); 6343 } 6344 free_percpu(sdd->sd); 6345 sdd->sd = NULL; 6346 free_percpu(sdd->sg); 6347 sdd->sg = NULL; 6348 free_percpu(sdd->sgp); 6349 sdd->sgp = NULL; 6350 } 6351} 6352 6353struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl, 6354 struct s_data *d, const struct cpumask *cpu_map, 6355 struct sched_domain_attr *attr, struct sched_domain *child, 6356 int cpu) 6357{ 6358 struct sched_domain *sd = tl->init(tl, cpu); 6359 if (!sd) 6360 return child; 6361 6362 cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu)); 6363 if (child) { 6364 sd->level = child->level + 1; 6365 sched_domain_level_max = max(sched_domain_level_max, sd->level); 6366 child->parent = sd; 6367 } 6368 sd->child = child; 6369 set_domain_attribute(sd, attr); 6370 6371 return sd; 6372} 6373 6374/* 6375 * Build sched domains for a given set of cpus and attach the sched domains 6376 * to the individual cpus 6377 */ 6378static int build_sched_domains(const struct cpumask *cpu_map, 6379 struct sched_domain_attr *attr) 6380{ 6381 enum s_alloc alloc_state = sa_none; 6382 struct sched_domain *sd; 6383 struct s_data d; 6384 int i, ret = -ENOMEM; 6385 6386 alloc_state = __visit_domain_allocation_hell(&d, cpu_map); 6387 if (alloc_state != sa_rootdomain) 6388 goto error; 6389 6390 /* Set up domains for cpus specified by the cpu_map. */ 6391 for_each_cpu(i, cpu_map) { 6392 struct sched_domain_topology_level *tl; 6393 6394 sd = NULL; 6395 for (tl = sched_domain_topology; tl->init; tl++) { 6396 sd = build_sched_domain(tl, &d, cpu_map, attr, sd, i); 6397 if (tl->flags & SDTL_OVERLAP || sched_feat(FORCE_SD_OVERLAP)) 6398 sd->flags |= SD_OVERLAP; 6399 if (cpumask_equal(cpu_map, sched_domain_span(sd))) 6400 break; 6401 } 6402 6403 while (sd->child) 6404 sd = sd->child; 6405 6406 *per_cpu_ptr(d.sd, i) = sd; 6407 } 6408 6409 /* Build the groups for the domains */ 6410 for_each_cpu(i, cpu_map) { 6411 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { 6412 sd->span_weight = cpumask_weight(sched_domain_span(sd)); 6413 if (sd->flags & SD_OVERLAP) { 6414 if (build_overlap_sched_groups(sd, i)) 6415 goto error; 6416 } else { 6417 if (build_sched_groups(sd, i)) 6418 goto error; 6419 } 6420 } 6421 } 6422 6423 /* Calculate CPU power for physical packages and nodes */ 6424 for (i = nr_cpumask_bits-1; i >= 0; i--) { 6425 if (!cpumask_test_cpu(i, cpu_map)) 6426 continue; 6427 6428 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { 6429 claim_allocations(i, sd); 6430 init_sched_groups_power(i, sd); 6431 } 6432 } 6433 6434 /* Attach the domains */ 6435 rcu_read_lock(); 6436 for_each_cpu(i, cpu_map) { 6437 sd = *per_cpu_ptr(d.sd, i); 6438 cpu_attach_domain(sd, d.rd, i); 6439 } 6440 rcu_read_unlock(); 6441 6442 ret = 0; 6443error: 6444 __free_domain_allocs(&d, alloc_state, cpu_map); 6445 return ret; 6446} 6447 6448static cpumask_var_t *doms_cur; /* current sched domains */ 6449static int ndoms_cur; /* number of sched domains in 'doms_cur' */ 6450static struct sched_domain_attr *dattr_cur; 6451 /* attribues of custom domains in 'doms_cur' */ 6452 6453/* 6454 * Special case: If a kmalloc of a doms_cur partition (array of 6455 * cpumask) fails, then fallback to a single sched domain, 6456 * as determined by the single cpumask fallback_doms. 6457 */ 6458static cpumask_var_t fallback_doms; 6459 6460/* 6461 * arch_update_cpu_topology lets virtualized architectures update the 6462 * cpu core maps. It is supposed to return 1 if the topology changed 6463 * or 0 if it stayed the same. 6464 */ 6465int __attribute__((weak)) arch_update_cpu_topology(void) 6466{ 6467 return 0; 6468} 6469 6470cpumask_var_t *alloc_sched_domains(unsigned int ndoms) 6471{ 6472 int i; 6473 cpumask_var_t *doms; 6474 6475 doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL); 6476 if (!doms) 6477 return NULL; 6478 for (i = 0; i < ndoms; i++) { 6479 if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) { 6480 free_sched_domains(doms, i); 6481 return NULL; 6482 } 6483 } 6484 return doms; 6485} 6486 6487void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms) 6488{ 6489 unsigned int i; 6490 for (i = 0; i < ndoms; i++) 6491 free_cpumask_var(doms[i]); 6492 kfree(doms); 6493} 6494 6495/* 6496 * Set up scheduler domains and groups. Callers must hold the hotplug lock. 6497 * For now this just excludes isolated cpus, but could be used to 6498 * exclude other special cases in the future. 6499 */ 6500static int init_sched_domains(const struct cpumask *cpu_map) 6501{ 6502 int err; 6503 6504 arch_update_cpu_topology(); 6505 ndoms_cur = 1; 6506 doms_cur = alloc_sched_domains(ndoms_cur); 6507 if (!doms_cur) 6508 doms_cur = &fallback_doms; 6509 cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map); 6510 err = build_sched_domains(doms_cur[0], NULL); 6511 register_sched_domain_sysctl(); 6512 6513 return err; 6514} 6515 6516/* 6517 * Detach sched domains from a group of cpus specified in cpu_map 6518 * These cpus will now be attached to the NULL domain 6519 */ 6520static void detach_destroy_domains(const struct cpumask *cpu_map) 6521{ 6522 int i; 6523 6524 rcu_read_lock(); 6525 for_each_cpu(i, cpu_map) 6526 cpu_attach_domain(NULL, &def_root_domain, i); 6527 rcu_read_unlock(); 6528} 6529 6530/* handle null as "default" */ 6531static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur, 6532 struct sched_domain_attr *new, int idx_new) 6533{ 6534 struct sched_domain_attr tmp; 6535 6536 /* fast path */ 6537 if (!new && !cur) 6538 return 1; 6539 6540 tmp = SD_ATTR_INIT; 6541 return !memcmp(cur ? (cur + idx_cur) : &tmp, 6542 new ? (new + idx_new) : &tmp, 6543 sizeof(struct sched_domain_attr)); 6544} 6545 6546/* 6547 * Partition sched domains as specified by the 'ndoms_new' 6548 * cpumasks in the array doms_new[] of cpumasks. This compares 6549 * doms_new[] to the current sched domain partitioning, doms_cur[]. 6550 * It destroys each deleted domain and builds each new domain. 6551 * 6552 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'. 6553 * The masks don't intersect (don't overlap.) We should setup one 6554 * sched domain for each mask. CPUs not in any of the cpumasks will 6555 * not be load balanced. If the same cpumask appears both in the 6556 * current 'doms_cur' domains and in the new 'doms_new', we can leave 6557 * it as it is. 6558 * 6559 * The passed in 'doms_new' should be allocated using 6560 * alloc_sched_domains. This routine takes ownership of it and will 6561 * free_sched_domains it when done with it. If the caller failed the 6562 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1, 6563 * and partition_sched_domains() will fallback to the single partition 6564 * 'fallback_doms', it also forces the domains to be rebuilt. 6565 * 6566 * If doms_new == NULL it will be replaced with cpu_online_mask. 6567 * ndoms_new == 0 is a special case for destroying existing domains, 6568 * and it will not create the default domain. 6569 * 6570 * Call with hotplug lock held 6571 */ 6572void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[], 6573 struct sched_domain_attr *dattr_new) 6574{ 6575 int i, j, n; 6576 int new_topology; 6577 6578 mutex_lock(&sched_domains_mutex); 6579 6580 /* always unregister in case we don't destroy any domains */ 6581 unregister_sched_domain_sysctl(); 6582 6583 /* Let architecture update cpu core mappings. */ 6584 new_topology = arch_update_cpu_topology(); 6585 6586 n = doms_new ? ndoms_new : 0; 6587 6588 /* Destroy deleted domains */ 6589 for (i = 0; i < ndoms_cur; i++) { 6590 for (j = 0; j < n && !new_topology; j++) { 6591 if (cpumask_equal(doms_cur[i], doms_new[j]) 6592 && dattrs_equal(dattr_cur, i, dattr_new, j)) 6593 goto match1; 6594 } 6595 /* no match - a current sched domain not in new doms_new[] */ 6596 detach_destroy_domains(doms_cur[i]); 6597match1: 6598 ; 6599 } 6600 6601 if (doms_new == NULL) { 6602 ndoms_cur = 0; 6603 doms_new = &fallback_doms; 6604 cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map); 6605 WARN_ON_ONCE(dattr_new); 6606 } 6607 6608 /* Build new domains */ 6609 for (i = 0; i < ndoms_new; i++) { 6610 for (j = 0; j < ndoms_cur && !new_topology; j++) { 6611 if (cpumask_equal(doms_new[i], doms_cur[j]) 6612 && dattrs_equal(dattr_new, i, dattr_cur, j)) 6613 goto match2; 6614 } 6615 /* no match - add a new doms_new */ 6616 build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL); 6617match2: 6618 ; 6619 } 6620 6621 /* Remember the new sched domains */ 6622 if (doms_cur != &fallback_doms) 6623 free_sched_domains(doms_cur, ndoms_cur); 6624 kfree(dattr_cur); /* kfree(NULL) is safe */ 6625 doms_cur = doms_new; 6626 dattr_cur = dattr_new; 6627 ndoms_cur = ndoms_new; 6628 6629 register_sched_domain_sysctl(); 6630 6631 mutex_unlock(&sched_domains_mutex); 6632} 6633 6634static int num_cpus_frozen; /* used to mark begin/end of suspend/resume */ 6635 6636/* 6637 * Update cpusets according to cpu_active mask. If cpusets are 6638 * disabled, cpuset_update_active_cpus() becomes a simple wrapper 6639 * around partition_sched_domains(). 6640 * 6641 * If we come here as part of a suspend/resume, don't touch cpusets because we 6642 * want to restore it back to its original state upon resume anyway. 6643 */ 6644static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action, 6645 void *hcpu) 6646{ 6647 switch (action) { 6648 case CPU_ONLINE_FROZEN: 6649 case CPU_DOWN_FAILED_FROZEN: 6650 6651 /* 6652 * num_cpus_frozen tracks how many CPUs are involved in suspend 6653 * resume sequence. As long as this is not the last online 6654 * operation in the resume sequence, just build a single sched 6655 * domain, ignoring cpusets. 6656 */ 6657 num_cpus_frozen--; 6658 if (likely(num_cpus_frozen)) { 6659 partition_sched_domains(1, NULL, NULL); 6660 break; 6661 } 6662 6663 /* 6664 * This is the last CPU online operation. So fall through and 6665 * restore the original sched domains by considering the 6666 * cpuset configurations. 6667 */ 6668 6669 case CPU_ONLINE: 6670 case CPU_DOWN_FAILED: 6671 cpuset_update_active_cpus(true); 6672 break; 6673 default: 6674 return NOTIFY_DONE; 6675 } 6676 return NOTIFY_OK; 6677} 6678 6679static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action, 6680 void *hcpu) 6681{ 6682 switch (action) { 6683 case CPU_DOWN_PREPARE: 6684 cpuset_update_active_cpus(false); 6685 break; 6686 case CPU_DOWN_PREPARE_FROZEN: 6687 num_cpus_frozen++; 6688 partition_sched_domains(1, NULL, NULL); 6689 break; 6690 default: 6691 return NOTIFY_DONE; 6692 } 6693 return NOTIFY_OK; 6694} 6695 6696void __init sched_init_smp(void) 6697{ 6698 cpumask_var_t non_isolated_cpus; 6699 6700 alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL); 6701 alloc_cpumask_var(&fallback_doms, GFP_KERNEL); 6702 6703 sched_init_numa(); 6704 6705 get_online_cpus(); 6706 mutex_lock(&sched_domains_mutex); 6707 init_sched_domains(cpu_active_mask); 6708 cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map); 6709 if (cpumask_empty(non_isolated_cpus)) 6710 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus); 6711 mutex_unlock(&sched_domains_mutex); 6712 put_online_cpus(); 6713 6714 hotcpu_notifier(sched_domains_numa_masks_update, CPU_PRI_SCHED_ACTIVE); 6715 hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE); 6716 hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE); 6717 6718 /* RT runtime code needs to handle some hotplug events */ 6719 hotcpu_notifier(update_runtime, 0); 6720 6721 init_hrtick(); 6722 6723 /* Move init over to a non-isolated CPU */ 6724 if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0) 6725 BUG(); 6726 sched_init_granularity(); 6727 free_cpumask_var(non_isolated_cpus); 6728 6729 init_sched_rt_class(); 6730} 6731#else 6732void __init sched_init_smp(void) 6733{ 6734 sched_init_granularity(); 6735} 6736#endif /* CONFIG_SMP */ 6737 6738const_debug unsigned int sysctl_timer_migration = 1; 6739 6740int in_sched_functions(unsigned long addr) 6741{ 6742 return in_lock_functions(addr) || 6743 (addr >= (unsigned long)__sched_text_start 6744 && addr < (unsigned long)__sched_text_end); 6745} 6746 6747#ifdef CONFIG_CGROUP_SCHED 6748struct task_group root_task_group; 6749LIST_HEAD(task_groups); 6750#endif 6751 6752DECLARE_PER_CPU(cpumask_var_t, load_balance_tmpmask); 6753 6754void __init sched_init(void) 6755{ 6756 int i, j; 6757 unsigned long alloc_size = 0, ptr; 6758 6759#ifdef CONFIG_FAIR_GROUP_SCHED 6760 alloc_size += 2 * nr_cpu_ids * sizeof(void **); 6761#endif 6762#ifdef CONFIG_RT_GROUP_SCHED 6763 alloc_size += 2 * nr_cpu_ids * sizeof(void **); 6764#endif 6765#ifdef CONFIG_CPUMASK_OFFSTACK 6766 alloc_size += num_possible_cpus() * cpumask_size(); 6767#endif 6768 if (alloc_size) { 6769 ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT); 6770 6771#ifdef CONFIG_FAIR_GROUP_SCHED 6772 root_task_group.se = (struct sched_entity **)ptr; 6773 ptr += nr_cpu_ids * sizeof(void **); 6774 6775 root_task_group.cfs_rq = (struct cfs_rq **)ptr; 6776 ptr += nr_cpu_ids * sizeof(void **); 6777 6778#endif /* CONFIG_FAIR_GROUP_SCHED */ 6779#ifdef CONFIG_RT_GROUP_SCHED 6780 root_task_group.rt_se = (struct sched_rt_entity **)ptr; 6781 ptr += nr_cpu_ids * sizeof(void **); 6782 6783 root_task_group.rt_rq = (struct rt_rq **)ptr; 6784 ptr += nr_cpu_ids * sizeof(void **); 6785 6786#endif /* CONFIG_RT_GROUP_SCHED */ 6787#ifdef CONFIG_CPUMASK_OFFSTACK 6788 for_each_possible_cpu(i) { 6789 per_cpu(load_balance_tmpmask, i) = (void *)ptr; 6790 ptr += cpumask_size(); 6791 } 6792#endif /* CONFIG_CPUMASK_OFFSTACK */ 6793 } 6794 6795#ifdef CONFIG_SMP 6796 init_defrootdomain(); 6797#endif 6798 6799 init_rt_bandwidth(&def_rt_bandwidth, 6800 global_rt_period(), global_rt_runtime()); 6801 6802#ifdef CONFIG_RT_GROUP_SCHED 6803 init_rt_bandwidth(&root_task_group.rt_bandwidth, 6804 global_rt_period(), global_rt_runtime()); 6805#endif /* CONFIG_RT_GROUP_SCHED */ 6806 6807#ifdef CONFIG_CGROUP_SCHED 6808 list_add(&root_task_group.list, &task_groups); 6809 INIT_LIST_HEAD(&root_task_group.children); 6810 INIT_LIST_HEAD(&root_task_group.siblings); 6811 autogroup_init(&init_task); 6812 6813#endif /* CONFIG_CGROUP_SCHED */ 6814 6815#ifdef CONFIG_CGROUP_CPUACCT 6816 root_cpuacct.cpustat = &kernel_cpustat; 6817 root_cpuacct.cpuusage = alloc_percpu(u64); 6818 /* Too early, not expected to fail */ 6819 BUG_ON(!root_cpuacct.cpuusage); 6820#endif 6821 for_each_possible_cpu(i) { 6822 struct rq *rq; 6823 6824 rq = cpu_rq(i); 6825 raw_spin_lock_init(&rq->lock); 6826 rq->nr_running = 0; 6827 rq->calc_load_active = 0; 6828 rq->calc_load_update = jiffies + LOAD_FREQ; 6829 init_cfs_rq(&rq->cfs); 6830 init_rt_rq(&rq->rt, rq); 6831#ifdef CONFIG_FAIR_GROUP_SCHED 6832 root_task_group.shares = ROOT_TASK_GROUP_LOAD; 6833 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list); 6834 /* 6835 * How much cpu bandwidth does root_task_group get? 6836 * 6837 * In case of task-groups formed thr' the cgroup filesystem, it 6838 * gets 100% of the cpu resources in the system. This overall 6839 * system cpu resource is divided among the tasks of 6840 * root_task_group and its child task-groups in a fair manner, 6841 * based on each entity's (task or task-group's) weight 6842 * (se->load.weight). 6843 * 6844 * In other words, if root_task_group has 10 tasks of weight 6845 * 1024) and two child groups A0 and A1 (of weight 1024 each), 6846 * then A0's share of the cpu resource is: 6847 * 6848 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33% 6849 * 6850 * We achieve this by letting root_task_group's tasks sit 6851 * directly in rq->cfs (i.e root_task_group->se[] = NULL). 6852 */ 6853 init_cfs_bandwidth(&root_task_group.cfs_bandwidth); 6854 init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL); 6855#endif /* CONFIG_FAIR_GROUP_SCHED */ 6856 6857 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime; 6858#ifdef CONFIG_RT_GROUP_SCHED 6859 INIT_LIST_HEAD(&rq->leaf_rt_rq_list); 6860 init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL); 6861#endif 6862 6863 for (j = 0; j < CPU_LOAD_IDX_MAX; j++) 6864 rq->cpu_load[j] = 0; 6865 6866 rq->last_load_update_tick = jiffies; 6867 6868#ifdef CONFIG_SMP 6869 rq->sd = NULL; 6870 rq->rd = NULL; 6871 rq->cpu_power = SCHED_POWER_SCALE; 6872 rq->post_schedule = 0; 6873 rq->active_balance = 0; 6874 rq->next_balance = jiffies; 6875 rq->push_cpu = 0; 6876 rq->cpu = i; 6877 rq->online = 0; 6878 rq->idle_stamp = 0; 6879 rq->avg_idle = 2*sysctl_sched_migration_cost; 6880 6881 INIT_LIST_HEAD(&rq->cfs_tasks); 6882 6883 rq_attach_root(rq, &def_root_domain); 6884#ifdef CONFIG_NO_HZ 6885 rq->nohz_flags = 0; 6886#endif 6887#endif 6888 init_rq_hrtick(rq); 6889 atomic_set(&rq->nr_iowait, 0); 6890 } 6891 6892 set_load_weight(&init_task); 6893 6894#ifdef CONFIG_PREEMPT_NOTIFIERS 6895 INIT_HLIST_HEAD(&init_task.preempt_notifiers); 6896#endif 6897 6898#ifdef CONFIG_RT_MUTEXES 6899 plist_head_init(&init_task.pi_waiters); 6900#endif 6901 6902 /* 6903 * The boot idle thread does lazy MMU switching as well: 6904 */ 6905 atomic_inc(&init_mm.mm_count); 6906 enter_lazy_tlb(&init_mm, current); 6907 6908 /* 6909 * Make us the idle thread. Technically, schedule() should not be 6910 * called from this thread, however somewhere below it might be, 6911 * but because we are the idle thread, we just pick up running again 6912 * when this runqueue becomes "idle". 6913 */ 6914 init_idle(current, smp_processor_id()); 6915 6916 calc_load_update = jiffies + LOAD_FREQ; 6917 6918 /* 6919 * During early bootup we pretend to be a normal task: 6920 */ 6921 current->sched_class = &fair_sched_class; 6922 6923#ifdef CONFIG_SMP 6924 zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT); 6925 /* May be allocated at isolcpus cmdline parse time */ 6926 if (cpu_isolated_map == NULL) 6927 zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT); 6928 idle_thread_set_boot_cpu(); 6929#endif 6930 init_sched_fair_class(); 6931 6932 scheduler_running = 1; 6933} 6934 6935#ifdef CONFIG_DEBUG_ATOMIC_SLEEP 6936static inline int preempt_count_equals(int preempt_offset) 6937{ 6938 int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth(); 6939 6940 return (nested == preempt_offset); 6941} 6942 6943void __might_sleep(const char *file, int line, int preempt_offset) 6944{ 6945 static unsigned long prev_jiffy; /* ratelimiting */ 6946 6947 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */ 6948 if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) || 6949 system_state != SYSTEM_RUNNING || oops_in_progress) 6950 return; 6951 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) 6952 return; 6953 prev_jiffy = jiffies; 6954 6955 printk(KERN_ERR 6956 "BUG: sleeping function called from invalid context at %s:%d\n", 6957 file, line); 6958 printk(KERN_ERR 6959 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n", 6960 in_atomic(), irqs_disabled(), 6961 current->pid, current->comm); 6962 6963 debug_show_held_locks(current); 6964 if (irqs_disabled()) 6965 print_irqtrace_events(current); 6966 dump_stack(); 6967} 6968EXPORT_SYMBOL(__might_sleep); 6969#endif 6970 6971#ifdef CONFIG_MAGIC_SYSRQ 6972static void normalize_task(struct rq *rq, struct task_struct *p) 6973{ 6974 const struct sched_class *prev_class = p->sched_class; 6975 int old_prio = p->prio; 6976 int on_rq; 6977 6978 on_rq = p->on_rq; 6979 if (on_rq) 6980 dequeue_task(rq, p, 0); 6981 __setscheduler(rq, p, SCHED_NORMAL, 0); 6982 if (on_rq) { 6983 enqueue_task(rq, p, 0); 6984 resched_task(rq->curr); 6985 } 6986 6987 check_class_changed(rq, p, prev_class, old_prio); 6988} 6989 6990void normalize_rt_tasks(void) 6991{ 6992 struct task_struct *g, *p; 6993 unsigned long flags; 6994 struct rq *rq; 6995 6996 read_lock_irqsave(&tasklist_lock, flags); 6997 do_each_thread(g, p) { 6998 /* 6999 * Only normalize user tasks: 7000 */ 7001 if (!p->mm) 7002 continue; 7003 7004 p->se.exec_start = 0; 7005#ifdef CONFIG_SCHEDSTATS 7006 p->se.statistics.wait_start = 0; 7007 p->se.statistics.sleep_start = 0; 7008 p->se.statistics.block_start = 0; 7009#endif 7010 7011 if (!rt_task(p)) { 7012 /* 7013 * Renice negative nice level userspace 7014 * tasks back to 0: 7015 */ 7016 if (TASK_NICE(p) < 0 && p->mm) 7017 set_user_nice(p, 0); 7018 continue; 7019 } 7020 7021 raw_spin_lock(&p->pi_lock); 7022 rq = __task_rq_lock(p); 7023 7024 normalize_task(rq, p); 7025 7026 __task_rq_unlock(rq); 7027 raw_spin_unlock(&p->pi_lock); 7028 } while_each_thread(g, p); 7029 7030 read_unlock_irqrestore(&tasklist_lock, flags); 7031} 7032 7033#endif /* CONFIG_MAGIC_SYSRQ */ 7034 7035#if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) 7036/* 7037 * These functions are only useful for the IA64 MCA handling, or kdb. 7038 * 7039 * They can only be called when the whole system has been 7040 * stopped - every CPU needs to be quiescent, and no scheduling 7041 * activity can take place. Using them for anything else would 7042 * be a serious bug, and as a result, they aren't even visible 7043 * under any other configuration. 7044 */ 7045 7046/** 7047 * curr_task - return the current task for a given cpu. 7048 * @cpu: the processor in question. 7049 * 7050 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! 7051 */ 7052struct task_struct *curr_task(int cpu) 7053{ 7054 return cpu_curr(cpu); 7055} 7056 7057#endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */ 7058 7059#ifdef CONFIG_IA64 7060/** 7061 * set_curr_task - set the current task for a given cpu. 7062 * @cpu: the processor in question. 7063 * @p: the task pointer to set. 7064 * 7065 * Description: This function must only be used when non-maskable interrupts 7066 * are serviced on a separate stack. It allows the architecture to switch the 7067 * notion of the current task on a cpu in a non-blocking manner. This function 7068 * must be called with all CPU's synchronized, and interrupts disabled, the 7069 * and caller must save the original value of the current task (see 7070 * curr_task() above) and restore that value before reenabling interrupts and 7071 * re-starting the system. 7072 * 7073 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! 7074 */ 7075void set_curr_task(int cpu, struct task_struct *p) 7076{ 7077 cpu_curr(cpu) = p; 7078} 7079 7080#endif 7081 7082#ifdef CONFIG_CGROUP_SCHED 7083/* task_group_lock serializes the addition/removal of task groups */ 7084static DEFINE_SPINLOCK(task_group_lock); 7085 7086static void free_sched_group(struct task_group *tg) 7087{ 7088 free_fair_sched_group(tg); 7089 free_rt_sched_group(tg); 7090 autogroup_free(tg); 7091 kfree(tg); 7092} 7093 7094/* allocate runqueue etc for a new task group */ 7095struct task_group *sched_create_group(struct task_group *parent) 7096{ 7097 struct task_group *tg; 7098 unsigned long flags; 7099 7100 tg = kzalloc(sizeof(*tg), GFP_KERNEL); 7101 if (!tg) 7102 return ERR_PTR(-ENOMEM); 7103 7104 if (!alloc_fair_sched_group(tg, parent)) 7105 goto err; 7106 7107 if (!alloc_rt_sched_group(tg, parent)) 7108 goto err; 7109 7110 spin_lock_irqsave(&task_group_lock, flags); 7111 list_add_rcu(&tg->list, &task_groups); 7112 7113 WARN_ON(!parent); /* root should already exist */ 7114 7115 tg->parent = parent; 7116 INIT_LIST_HEAD(&tg->children); 7117 list_add_rcu(&tg->siblings, &parent->children); 7118 spin_unlock_irqrestore(&task_group_lock, flags); 7119 7120 return tg; 7121 7122err: 7123 free_sched_group(tg); 7124 return ERR_PTR(-ENOMEM); 7125} 7126 7127/* rcu callback to free various structures associated with a task group */ 7128static void free_sched_group_rcu(struct rcu_head *rhp) 7129{ 7130 /* now it should be safe to free those cfs_rqs */ 7131 free_sched_group(container_of(rhp, struct task_group, rcu)); 7132} 7133 7134/* Destroy runqueue etc associated with a task group */ 7135void sched_destroy_group(struct task_group *tg) 7136{ 7137 unsigned long flags; 7138 int i; 7139 7140 /* end participation in shares distribution */ 7141 for_each_possible_cpu(i) 7142 unregister_fair_sched_group(tg, i); 7143 7144 spin_lock_irqsave(&task_group_lock, flags); 7145 list_del_rcu(&tg->list); 7146 list_del_rcu(&tg->siblings); 7147 spin_unlock_irqrestore(&task_group_lock, flags); 7148 7149 /* wait for possible concurrent references to cfs_rqs complete */ 7150 call_rcu(&tg->rcu, free_sched_group_rcu); 7151} 7152 7153/* change task's runqueue when it moves between groups. 7154 * The caller of this function should have put the task in its new group 7155 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to 7156 * reflect its new group. 7157 */ 7158void sched_move_task(struct task_struct *tsk) 7159{ 7160 struct task_group *tg; 7161 int on_rq, running; 7162 unsigned long flags; 7163 struct rq *rq; 7164 7165 rq = task_rq_lock(tsk, &flags); 7166 7167 running = task_current(rq, tsk); 7168 on_rq = tsk->on_rq; 7169 7170 if (on_rq) 7171 dequeue_task(rq, tsk, 0); 7172 if (unlikely(running)) 7173 tsk->sched_class->put_prev_task(rq, tsk); 7174 7175 tg = container_of(task_subsys_state_check(tsk, cpu_cgroup_subsys_id, 7176 lockdep_is_held(&tsk->sighand->siglock)), 7177 struct task_group, css); 7178 tg = autogroup_task_group(tsk, tg); 7179 tsk->sched_task_group = tg; 7180 7181#ifdef CONFIG_FAIR_GROUP_SCHED 7182 if (tsk->sched_class->task_move_group) 7183 tsk->sched_class->task_move_group(tsk, on_rq); 7184 else 7185#endif 7186 set_task_rq(tsk, task_cpu(tsk)); 7187 7188 if (unlikely(running)) 7189 tsk->sched_class->set_curr_task(rq); 7190 if (on_rq) 7191 enqueue_task(rq, tsk, 0); 7192 7193 task_rq_unlock(rq, tsk, &flags); 7194} 7195#endif /* CONFIG_CGROUP_SCHED */ 7196 7197#if defined(CONFIG_RT_GROUP_SCHED) || defined(CONFIG_CFS_BANDWIDTH) 7198static unsigned long to_ratio(u64 period, u64 runtime) 7199{ 7200 if (runtime == RUNTIME_INF) 7201 return 1ULL << 20; 7202 7203 return div64_u64(runtime << 20, period); 7204} 7205#endif 7206 7207#ifdef CONFIG_RT_GROUP_SCHED 7208/* 7209 * Ensure that the real time constraints are schedulable. 7210 */ 7211static DEFINE_MUTEX(rt_constraints_mutex); 7212 7213/* Must be called with tasklist_lock held */ 7214static inline int tg_has_rt_tasks(struct task_group *tg) 7215{ 7216 struct task_struct *g, *p; 7217 7218 do_each_thread(g, p) { 7219 if (rt_task(p) && task_rq(p)->rt.tg == tg) 7220 return 1; 7221 } while_each_thread(g, p); 7222 7223 return 0; 7224} 7225 7226struct rt_schedulable_data { 7227 struct task_group *tg; 7228 u64 rt_period; 7229 u64 rt_runtime; 7230}; 7231 7232static int tg_rt_schedulable(struct task_group *tg, void *data) 7233{ 7234 struct rt_schedulable_data *d = data; 7235 struct task_group *child; 7236 unsigned long total, sum = 0; 7237 u64 period, runtime; 7238 7239 period = ktime_to_ns(tg->rt_bandwidth.rt_period); 7240 runtime = tg->rt_bandwidth.rt_runtime; 7241 7242 if (tg == d->tg) { 7243 period = d->rt_period; 7244 runtime = d->rt_runtime; 7245 } 7246 7247 /* 7248 * Cannot have more runtime than the period. 7249 */ 7250 if (runtime > period && runtime != RUNTIME_INF) 7251 return -EINVAL; 7252 7253 /* 7254 * Ensure we don't starve existing RT tasks. 7255 */ 7256 if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg)) 7257 return -EBUSY; 7258 7259 total = to_ratio(period, runtime); 7260 7261 /* 7262 * Nobody can have more than the global setting allows. 7263 */ 7264 if (total > to_ratio(global_rt_period(), global_rt_runtime())) 7265 return -EINVAL; 7266 7267 /* 7268 * The sum of our children's runtime should not exceed our own. 7269 */ 7270 list_for_each_entry_rcu(child, &tg->children, siblings) { 7271 period = ktime_to_ns(child->rt_bandwidth.rt_period); 7272 runtime = child->rt_bandwidth.rt_runtime; 7273 7274 if (child == d->tg) { 7275 period = d->rt_period; 7276 runtime = d->rt_runtime; 7277 } 7278 7279 sum += to_ratio(period, runtime); 7280 } 7281 7282 if (sum > total) 7283 return -EINVAL; 7284 7285 return 0; 7286} 7287 7288static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime) 7289{ 7290 int ret; 7291 7292 struct rt_schedulable_data data = { 7293 .tg = tg, 7294 .rt_period = period, 7295 .rt_runtime = runtime, 7296 }; 7297 7298 rcu_read_lock(); 7299 ret = walk_tg_tree(tg_rt_schedulable, tg_nop, &data); 7300 rcu_read_unlock(); 7301 7302 return ret; 7303} 7304 7305static int tg_set_rt_bandwidth(struct task_group *tg, 7306 u64 rt_period, u64 rt_runtime) 7307{ 7308 int i, err = 0; 7309 7310 mutex_lock(&rt_constraints_mutex); 7311 read_lock(&tasklist_lock); 7312 err = __rt_schedulable(tg, rt_period, rt_runtime); 7313 if (err) 7314 goto unlock; 7315 7316 raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock); 7317 tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period); 7318 tg->rt_bandwidth.rt_runtime = rt_runtime; 7319 7320 for_each_possible_cpu(i) { 7321 struct rt_rq *rt_rq = tg->rt_rq[i]; 7322 7323 raw_spin_lock(&rt_rq->rt_runtime_lock); 7324 rt_rq->rt_runtime = rt_runtime; 7325 raw_spin_unlock(&rt_rq->rt_runtime_lock); 7326 } 7327 raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock); 7328unlock: 7329 read_unlock(&tasklist_lock); 7330 mutex_unlock(&rt_constraints_mutex); 7331 7332 return err; 7333} 7334 7335int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us) 7336{ 7337 u64 rt_runtime, rt_period; 7338 7339 rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period); 7340 rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC; 7341 if (rt_runtime_us < 0) 7342 rt_runtime = RUNTIME_INF; 7343 7344 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); 7345} 7346 7347long sched_group_rt_runtime(struct task_group *tg) 7348{ 7349 u64 rt_runtime_us; 7350 7351 if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF) 7352 return -1; 7353 7354 rt_runtime_us = tg->rt_bandwidth.rt_runtime; 7355 do_div(rt_runtime_us, NSEC_PER_USEC); 7356 return rt_runtime_us; 7357} 7358 7359int sched_group_set_rt_period(struct task_group *tg, long rt_period_us) 7360{ 7361 u64 rt_runtime, rt_period; 7362 7363 rt_period = (u64)rt_period_us * NSEC_PER_USEC; 7364 rt_runtime = tg->rt_bandwidth.rt_runtime; 7365 7366 if (rt_period == 0) 7367 return -EINVAL; 7368 7369 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); 7370} 7371 7372long sched_group_rt_period(struct task_group *tg) 7373{ 7374 u64 rt_period_us; 7375 7376 rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period); 7377 do_div(rt_period_us, NSEC_PER_USEC); 7378 return rt_period_us; 7379} 7380 7381static int sched_rt_global_constraints(void) 7382{ 7383 u64 runtime, period; 7384 int ret = 0; 7385 7386 if (sysctl_sched_rt_period <= 0) 7387 return -EINVAL; 7388 7389 runtime = global_rt_runtime(); 7390 period = global_rt_period(); 7391 7392 /* 7393 * Sanity check on the sysctl variables. 7394 */ 7395 if (runtime > period && runtime != RUNTIME_INF) 7396 return -EINVAL; 7397 7398 mutex_lock(&rt_constraints_mutex); 7399 read_lock(&tasklist_lock); 7400 ret = __rt_schedulable(NULL, 0, 0); 7401 read_unlock(&tasklist_lock); 7402 mutex_unlock(&rt_constraints_mutex); 7403 7404 return ret; 7405} 7406 7407int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk) 7408{ 7409 /* Don't accept realtime tasks when there is no way for them to run */ 7410 if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0) 7411 return 0; 7412 7413 return 1; 7414} 7415 7416#else /* !CONFIG_RT_GROUP_SCHED */ 7417static int sched_rt_global_constraints(void) 7418{ 7419 unsigned long flags; 7420 int i; 7421 7422 if (sysctl_sched_rt_period <= 0) 7423 return -EINVAL; 7424 7425 /* 7426 * There's always some RT tasks in the root group 7427 * -- migration, kstopmachine etc.. 7428 */ 7429 if (sysctl_sched_rt_runtime == 0) 7430 return -EBUSY; 7431 7432 raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags); 7433 for_each_possible_cpu(i) { 7434 struct rt_rq *rt_rq = &cpu_rq(i)->rt; 7435 7436 raw_spin_lock(&rt_rq->rt_runtime_lock); 7437 rt_rq->rt_runtime = global_rt_runtime(); 7438 raw_spin_unlock(&rt_rq->rt_runtime_lock); 7439 } 7440 raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags); 7441 7442 return 0; 7443} 7444#endif /* CONFIG_RT_GROUP_SCHED */ 7445 7446int sched_rt_handler(struct ctl_table *table, int write, 7447 void __user *buffer, size_t *lenp, 7448 loff_t *ppos) 7449{ 7450 int ret; 7451 int old_period, old_runtime; 7452 static DEFINE_MUTEX(mutex); 7453 7454 mutex_lock(&mutex); 7455 old_period = sysctl_sched_rt_period; 7456 old_runtime = sysctl_sched_rt_runtime; 7457 7458 ret = proc_dointvec(table, write, buffer, lenp, ppos); 7459 7460 if (!ret && write) { 7461 ret = sched_rt_global_constraints(); 7462 if (ret) { 7463 sysctl_sched_rt_period = old_period; 7464 sysctl_sched_rt_runtime = old_runtime; 7465 } else { 7466 def_rt_bandwidth.rt_runtime = global_rt_runtime(); 7467 def_rt_bandwidth.rt_period = 7468 ns_to_ktime(global_rt_period()); 7469 } 7470 } 7471 mutex_unlock(&mutex); 7472 7473 return ret; 7474} 7475 7476#ifdef CONFIG_CGROUP_SCHED 7477 7478/* return corresponding task_group object of a cgroup */ 7479static inline struct task_group *cgroup_tg(struct cgroup *cgrp) 7480{ 7481 return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id), 7482 struct task_group, css); 7483} 7484 7485static struct cgroup_subsys_state *cpu_cgroup_create(struct cgroup *cgrp) 7486{ 7487 struct task_group *tg, *parent; 7488 7489 if (!cgrp->parent) { 7490 /* This is early initialization for the top cgroup */ 7491 return &root_task_group.css; 7492 } 7493 7494 parent = cgroup_tg(cgrp->parent); 7495 tg = sched_create_group(parent); 7496 if (IS_ERR(tg)) 7497 return ERR_PTR(-ENOMEM); 7498 7499 return &tg->css; 7500} 7501 7502static void cpu_cgroup_destroy(struct cgroup *cgrp) 7503{ 7504 struct task_group *tg = cgroup_tg(cgrp); 7505 7506 sched_destroy_group(tg); 7507} 7508 7509static int cpu_cgroup_can_attach(struct cgroup *cgrp, 7510 struct cgroup_taskset *tset) 7511{ 7512 struct task_struct *task; 7513 7514 cgroup_taskset_for_each(task, cgrp, tset) { 7515#ifdef CONFIG_RT_GROUP_SCHED 7516 if (!sched_rt_can_attach(cgroup_tg(cgrp), task)) 7517 return -EINVAL; 7518#else 7519 /* We don't support RT-tasks being in separate groups */ 7520 if (task->sched_class != &fair_sched_class) 7521 return -EINVAL; 7522#endif 7523 } 7524 return 0; 7525} 7526 7527static void cpu_cgroup_attach(struct cgroup *cgrp, 7528 struct cgroup_taskset *tset) 7529{ 7530 struct task_struct *task; 7531 7532 cgroup_taskset_for_each(task, cgrp, tset) 7533 sched_move_task(task); 7534} 7535 7536static void 7537cpu_cgroup_exit(struct cgroup *cgrp, struct cgroup *old_cgrp, 7538 struct task_struct *task) 7539{ 7540 /* 7541 * cgroup_exit() is called in the copy_process() failure path. 7542 * Ignore this case since the task hasn't ran yet, this avoids 7543 * trying to poke a half freed task state from generic code. 7544 */ 7545 if (!(task->flags & PF_EXITING)) 7546 return; 7547 7548 sched_move_task(task); 7549} 7550 7551#ifdef CONFIG_FAIR_GROUP_SCHED 7552static int cpu_shares_write_u64(struct cgroup *cgrp, struct cftype *cftype, 7553 u64 shareval) 7554{ 7555 return sched_group_set_shares(cgroup_tg(cgrp), scale_load(shareval)); 7556} 7557 7558static u64 cpu_shares_read_u64(struct cgroup *cgrp, struct cftype *cft) 7559{ 7560 struct task_group *tg = cgroup_tg(cgrp); 7561 7562 return (u64) scale_load_down(tg->shares); 7563} 7564 7565#ifdef CONFIG_CFS_BANDWIDTH 7566static DEFINE_MUTEX(cfs_constraints_mutex); 7567 7568const u64 max_cfs_quota_period = 1 * NSEC_PER_SEC; /* 1s */ 7569const u64 min_cfs_quota_period = 1 * NSEC_PER_MSEC; /* 1ms */ 7570 7571static int __cfs_schedulable(struct task_group *tg, u64 period, u64 runtime); 7572 7573static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota) 7574{ 7575 int i, ret = 0, runtime_enabled, runtime_was_enabled; 7576 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 7577 7578 if (tg == &root_task_group) 7579 return -EINVAL; 7580 7581 /* 7582 * Ensure we have at some amount of bandwidth every period. This is 7583 * to prevent reaching a state of large arrears when throttled via 7584 * entity_tick() resulting in prolonged exit starvation. 7585 */ 7586 if (quota < min_cfs_quota_period || period < min_cfs_quota_period) 7587 return -EINVAL; 7588 7589 /* 7590 * Likewise, bound things on the otherside by preventing insane quota 7591 * periods. This also allows us to normalize in computing quota 7592 * feasibility. 7593 */ 7594 if (period > max_cfs_quota_period) 7595 return -EINVAL; 7596 7597 mutex_lock(&cfs_constraints_mutex); 7598 ret = __cfs_schedulable(tg, period, quota); 7599 if (ret) 7600 goto out_unlock; 7601 7602 runtime_enabled = quota != RUNTIME_INF; 7603 runtime_was_enabled = cfs_b->quota != RUNTIME_INF; 7604 account_cfs_bandwidth_used(runtime_enabled, runtime_was_enabled); 7605 raw_spin_lock_irq(&cfs_b->lock); 7606 cfs_b->period = ns_to_ktime(period); 7607 cfs_b->quota = quota; 7608 7609 __refill_cfs_bandwidth_runtime(cfs_b); 7610 /* restart the period timer (if active) to handle new period expiry */ 7611 if (runtime_enabled && cfs_b->timer_active) { 7612 /* force a reprogram */ 7613 cfs_b->timer_active = 0; 7614 __start_cfs_bandwidth(cfs_b); 7615 } 7616 raw_spin_unlock_irq(&cfs_b->lock); 7617 7618 for_each_possible_cpu(i) { 7619 struct cfs_rq *cfs_rq = tg->cfs_rq[i]; 7620 struct rq *rq = cfs_rq->rq; 7621 7622 raw_spin_lock_irq(&rq->lock); 7623 cfs_rq->runtime_enabled = runtime_enabled; 7624 cfs_rq->runtime_remaining = 0; 7625 7626 if (cfs_rq->throttled) 7627 unthrottle_cfs_rq(cfs_rq); 7628 raw_spin_unlock_irq(&rq->lock); 7629 } 7630out_unlock: 7631 mutex_unlock(&cfs_constraints_mutex); 7632 7633 return ret; 7634} 7635 7636int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us) 7637{ 7638 u64 quota, period; 7639 7640 period = ktime_to_ns(tg->cfs_bandwidth.period); 7641 if (cfs_quota_us < 0) 7642 quota = RUNTIME_INF; 7643 else 7644 quota = (u64)cfs_quota_us * NSEC_PER_USEC; 7645 7646 return tg_set_cfs_bandwidth(tg, period, quota); 7647} 7648 7649long tg_get_cfs_quota(struct task_group *tg) 7650{ 7651 u64 quota_us; 7652 7653 if (tg->cfs_bandwidth.quota == RUNTIME_INF) 7654 return -1; 7655 7656 quota_us = tg->cfs_bandwidth.quota; 7657 do_div(quota_us, NSEC_PER_USEC); 7658 7659 return quota_us; 7660} 7661 7662int tg_set_cfs_period(struct task_group *tg, long cfs_period_us) 7663{ 7664 u64 quota, period; 7665 7666 period = (u64)cfs_period_us * NSEC_PER_USEC; 7667 quota = tg->cfs_bandwidth.quota; 7668 7669 return tg_set_cfs_bandwidth(tg, period, quota); 7670} 7671 7672long tg_get_cfs_period(struct task_group *tg) 7673{ 7674 u64 cfs_period_us; 7675 7676 cfs_period_us = ktime_to_ns(tg->cfs_bandwidth.period); 7677 do_div(cfs_period_us, NSEC_PER_USEC); 7678 7679 return cfs_period_us; 7680} 7681 7682static s64 cpu_cfs_quota_read_s64(struct cgroup *cgrp, struct cftype *cft) 7683{ 7684 return tg_get_cfs_quota(cgroup_tg(cgrp)); 7685} 7686 7687static int cpu_cfs_quota_write_s64(struct cgroup *cgrp, struct cftype *cftype, 7688 s64 cfs_quota_us) 7689{ 7690 return tg_set_cfs_quota(cgroup_tg(cgrp), cfs_quota_us); 7691} 7692 7693static u64 cpu_cfs_period_read_u64(struct cgroup *cgrp, struct cftype *cft) 7694{ 7695 return tg_get_cfs_period(cgroup_tg(cgrp)); 7696} 7697 7698static int cpu_cfs_period_write_u64(struct cgroup *cgrp, struct cftype *cftype, 7699 u64 cfs_period_us) 7700{ 7701 return tg_set_cfs_period(cgroup_tg(cgrp), cfs_period_us); 7702} 7703 7704struct cfs_schedulable_data { 7705 struct task_group *tg; 7706 u64 period, quota; 7707}; 7708 7709/* 7710 * normalize group quota/period to be quota/max_period 7711 * note: units are usecs 7712 */ 7713static u64 normalize_cfs_quota(struct task_group *tg, 7714 struct cfs_schedulable_data *d) 7715{ 7716 u64 quota, period; 7717 7718 if (tg == d->tg) { 7719 period = d->period; 7720 quota = d->quota; 7721 } else { 7722 period = tg_get_cfs_period(tg); 7723 quota = tg_get_cfs_quota(tg); 7724 } 7725 7726 /* note: these should typically be equivalent */ 7727 if (quota == RUNTIME_INF || quota == -1) 7728 return RUNTIME_INF; 7729 7730 return to_ratio(period, quota); 7731} 7732 7733static int tg_cfs_schedulable_down(struct task_group *tg, void *data) 7734{ 7735 struct cfs_schedulable_data *d = data; 7736 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 7737 s64 quota = 0, parent_quota = -1; 7738 7739 if (!tg->parent) { 7740 quota = RUNTIME_INF; 7741 } else { 7742 struct cfs_bandwidth *parent_b = &tg->parent->cfs_bandwidth; 7743 7744 quota = normalize_cfs_quota(tg, d); 7745 parent_quota = parent_b->hierarchal_quota; 7746 7747 /* 7748 * ensure max(child_quota) <= parent_quota, inherit when no 7749 * limit is set 7750 */ 7751 if (quota == RUNTIME_INF) 7752 quota = parent_quota; 7753 else if (parent_quota != RUNTIME_INF && quota > parent_quota) 7754 return -EINVAL; 7755 } 7756 cfs_b->hierarchal_quota = quota; 7757 7758 return 0; 7759} 7760 7761static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota) 7762{ 7763 int ret; 7764 struct cfs_schedulable_data data = { 7765 .tg = tg, 7766 .period = period, 7767 .quota = quota, 7768 }; 7769 7770 if (quota != RUNTIME_INF) { 7771 do_div(data.period, NSEC_PER_USEC); 7772 do_div(data.quota, NSEC_PER_USEC); 7773 } 7774 7775 rcu_read_lock(); 7776 ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data); 7777 rcu_read_unlock(); 7778 7779 return ret; 7780} 7781 7782static int cpu_stats_show(struct cgroup *cgrp, struct cftype *cft, 7783 struct cgroup_map_cb *cb) 7784{ 7785 struct task_group *tg = cgroup_tg(cgrp); 7786 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 7787 7788 cb->fill(cb, "nr_periods", cfs_b->nr_periods); 7789 cb->fill(cb, "nr_throttled", cfs_b->nr_throttled); 7790 cb->fill(cb, "throttled_time", cfs_b->throttled_time); 7791 7792 return 0; 7793} 7794#endif /* CONFIG_CFS_BANDWIDTH */ 7795#endif /* CONFIG_FAIR_GROUP_SCHED */ 7796 7797#ifdef CONFIG_RT_GROUP_SCHED 7798static int cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft, 7799 s64 val) 7800{ 7801 return sched_group_set_rt_runtime(cgroup_tg(cgrp), val); 7802} 7803 7804static s64 cpu_rt_runtime_read(struct cgroup *cgrp, struct cftype *cft) 7805{ 7806 return sched_group_rt_runtime(cgroup_tg(cgrp)); 7807} 7808 7809static int cpu_rt_period_write_uint(struct cgroup *cgrp, struct cftype *cftype, 7810 u64 rt_period_us) 7811{ 7812 return sched_group_set_rt_period(cgroup_tg(cgrp), rt_period_us); 7813} 7814 7815static u64 cpu_rt_period_read_uint(struct cgroup *cgrp, struct cftype *cft) 7816{ 7817 return sched_group_rt_period(cgroup_tg(cgrp)); 7818} 7819#endif /* CONFIG_RT_GROUP_SCHED */ 7820 7821static struct cftype cpu_files[] = { 7822#ifdef CONFIG_FAIR_GROUP_SCHED 7823 { 7824 .name = "shares", 7825 .read_u64 = cpu_shares_read_u64, 7826 .write_u64 = cpu_shares_write_u64, 7827 }, 7828#endif 7829#ifdef CONFIG_CFS_BANDWIDTH 7830 { 7831 .name = "cfs_quota_us", 7832 .read_s64 = cpu_cfs_quota_read_s64, 7833 .write_s64 = cpu_cfs_quota_write_s64, 7834 }, 7835 { 7836 .name = "cfs_period_us", 7837 .read_u64 = cpu_cfs_period_read_u64, 7838 .write_u64 = cpu_cfs_period_write_u64, 7839 }, 7840 { 7841 .name = "stat", 7842 .read_map = cpu_stats_show, 7843 }, 7844#endif 7845#ifdef CONFIG_RT_GROUP_SCHED 7846 { 7847 .name = "rt_runtime_us", 7848 .read_s64 = cpu_rt_runtime_read, 7849 .write_s64 = cpu_rt_runtime_write, 7850 }, 7851 { 7852 .name = "rt_period_us", 7853 .read_u64 = cpu_rt_period_read_uint, 7854 .write_u64 = cpu_rt_period_write_uint, 7855 }, 7856#endif 7857 { } /* terminate */ 7858}; 7859 7860struct cgroup_subsys cpu_cgroup_subsys = { 7861 .name = "cpu", 7862 .create = cpu_cgroup_create, 7863 .destroy = cpu_cgroup_destroy, 7864 .can_attach = cpu_cgroup_can_attach, 7865 .attach = cpu_cgroup_attach, 7866 .exit = cpu_cgroup_exit, 7867 .subsys_id = cpu_cgroup_subsys_id, 7868 .base_cftypes = cpu_files, 7869 .early_init = 1, 7870}; 7871 7872#endif /* CONFIG_CGROUP_SCHED */ 7873 7874#ifdef CONFIG_CGROUP_CPUACCT 7875 7876/* 7877 * CPU accounting code for task groups. 7878 * 7879 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh 7880 * (balbir@in.ibm.com). 7881 */ 7882 7883struct cpuacct root_cpuacct; 7884 7885/* create a new cpu accounting group */ 7886static struct cgroup_subsys_state *cpuacct_create(struct cgroup *cgrp) 7887{ 7888 struct cpuacct *ca; 7889 7890 if (!cgrp->parent) 7891 return &root_cpuacct.css; 7892 7893 ca = kzalloc(sizeof(*ca), GFP_KERNEL); 7894 if (!ca) 7895 goto out; 7896 7897 ca->cpuusage = alloc_percpu(u64); 7898 if (!ca->cpuusage) 7899 goto out_free_ca; 7900 7901 ca->cpustat = alloc_percpu(struct kernel_cpustat); 7902 if (!ca->cpustat) 7903 goto out_free_cpuusage; 7904 7905 return &ca->css; 7906 7907out_free_cpuusage: 7908 free_percpu(ca->cpuusage); 7909out_free_ca: 7910 kfree(ca); 7911out: 7912 return ERR_PTR(-ENOMEM); 7913} 7914 7915/* destroy an existing cpu accounting group */ 7916static void cpuacct_destroy(struct cgroup *cgrp) 7917{ 7918 struct cpuacct *ca = cgroup_ca(cgrp); 7919 7920 free_percpu(ca->cpustat); 7921 free_percpu(ca->cpuusage); 7922 kfree(ca); 7923} 7924 7925static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu) 7926{ 7927 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); 7928 u64 data; 7929 7930#ifndef CONFIG_64BIT 7931 /* 7932 * Take rq->lock to make 64-bit read safe on 32-bit platforms. 7933 */ 7934 raw_spin_lock_irq(&cpu_rq(cpu)->lock); 7935 data = *cpuusage; 7936 raw_spin_unlock_irq(&cpu_rq(cpu)->lock); 7937#else 7938 data = *cpuusage; 7939#endif 7940 7941 return data; 7942} 7943 7944static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val) 7945{ 7946 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); 7947 7948#ifndef CONFIG_64BIT 7949 /* 7950 * Take rq->lock to make 64-bit write safe on 32-bit platforms. 7951 */ 7952 raw_spin_lock_irq(&cpu_rq(cpu)->lock); 7953 *cpuusage = val; 7954 raw_spin_unlock_irq(&cpu_rq(cpu)->lock); 7955#else 7956 *cpuusage = val; 7957#endif 7958} 7959 7960/* return total cpu usage (in nanoseconds) of a group */ 7961static u64 cpuusage_read(struct cgroup *cgrp, struct cftype *cft) 7962{ 7963 struct cpuacct *ca = cgroup_ca(cgrp); 7964 u64 totalcpuusage = 0; 7965 int i; 7966 7967 for_each_present_cpu(i) 7968 totalcpuusage += cpuacct_cpuusage_read(ca, i); 7969 7970 return totalcpuusage; 7971} 7972 7973static int cpuusage_write(struct cgroup *cgrp, struct cftype *cftype, 7974 u64 reset) 7975{ 7976 struct cpuacct *ca = cgroup_ca(cgrp); 7977 int err = 0; 7978 int i; 7979 7980 if (reset) { 7981 err = -EINVAL; 7982 goto out; 7983 } 7984 7985 for_each_present_cpu(i) 7986 cpuacct_cpuusage_write(ca, i, 0); 7987 7988out: 7989 return err; 7990} 7991 7992static int cpuacct_percpu_seq_read(struct cgroup *cgroup, struct cftype *cft, 7993 struct seq_file *m) 7994{ 7995 struct cpuacct *ca = cgroup_ca(cgroup); 7996 u64 percpu; 7997 int i; 7998 7999 for_each_present_cpu(i) { 8000 percpu = cpuacct_cpuusage_read(ca, i); 8001 seq_printf(m, "%llu ", (unsigned long long) percpu); 8002 } 8003 seq_printf(m, "\n"); 8004 return 0; 8005} 8006 8007static const char *cpuacct_stat_desc[] = { 8008 [CPUACCT_STAT_USER] = "user", 8009 [CPUACCT_STAT_SYSTEM] = "system", 8010}; 8011 8012static int cpuacct_stats_show(struct cgroup *cgrp, struct cftype *cft, 8013 struct cgroup_map_cb *cb) 8014{ 8015 struct cpuacct *ca = cgroup_ca(cgrp); 8016 int cpu; 8017 s64 val = 0; 8018 8019 for_each_online_cpu(cpu) { 8020 struct kernel_cpustat *kcpustat = per_cpu_ptr(ca->cpustat, cpu); 8021 val += kcpustat->cpustat[CPUTIME_USER]; 8022 val += kcpustat->cpustat[CPUTIME_NICE]; 8023 } 8024 val = cputime64_to_clock_t(val); 8025 cb->fill(cb, cpuacct_stat_desc[CPUACCT_STAT_USER], val); 8026 8027 val = 0; 8028 for_each_online_cpu(cpu) { 8029 struct kernel_cpustat *kcpustat = per_cpu_ptr(ca->cpustat, cpu); 8030 val += kcpustat->cpustat[CPUTIME_SYSTEM]; 8031 val += kcpustat->cpustat[CPUTIME_IRQ]; 8032 val += kcpustat->cpustat[CPUTIME_SOFTIRQ]; 8033 } 8034 8035 val = cputime64_to_clock_t(val); 8036 cb->fill(cb, cpuacct_stat_desc[CPUACCT_STAT_SYSTEM], val); 8037 8038 return 0; 8039} 8040 8041static struct cftype files[] = { 8042 { 8043 .name = "usage", 8044 .read_u64 = cpuusage_read, 8045 .write_u64 = cpuusage_write, 8046 }, 8047 { 8048 .name = "usage_percpu", 8049 .read_seq_string = cpuacct_percpu_seq_read, 8050 }, 8051 { 8052 .name = "stat", 8053 .read_map = cpuacct_stats_show, 8054 }, 8055 { } /* terminate */ 8056}; 8057 8058/* 8059 * charge this task's execution time to its accounting group. 8060 * 8061 * called with rq->lock held. 8062 */ 8063void cpuacct_charge(struct task_struct *tsk, u64 cputime) 8064{ 8065 struct cpuacct *ca; 8066 int cpu; 8067 8068 if (unlikely(!cpuacct_subsys.active)) 8069 return; 8070 8071 cpu = task_cpu(tsk); 8072 8073 rcu_read_lock(); 8074 8075 ca = task_ca(tsk); 8076 8077 for (; ca; ca = parent_ca(ca)) { 8078 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); 8079 *cpuusage += cputime; 8080 } 8081 8082 rcu_read_unlock(); 8083} 8084 8085struct cgroup_subsys cpuacct_subsys = { 8086 .name = "cpuacct", 8087 .create = cpuacct_create, 8088 .destroy = cpuacct_destroy, 8089 .subsys_id = cpuacct_subsys_id, 8090 .base_cftypes = files, 8091}; 8092#endif /* CONFIG_CGROUP_CPUACCT */ 8093