core.c revision 9c806aa06f8e121c6058db8e8073798aa5c4355b
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 87#define CREATE_TRACE_POINTS 88#include <trace/events/sched.h> 89 90void start_bandwidth_timer(struct hrtimer *period_timer, ktime_t period) 91{ 92 unsigned long delta; 93 ktime_t soft, hard, now; 94 95 for (;;) { 96 if (hrtimer_active(period_timer)) 97 break; 98 99 now = hrtimer_cb_get_time(period_timer); 100 hrtimer_forward(period_timer, now, period); 101 102 soft = hrtimer_get_softexpires(period_timer); 103 hard = hrtimer_get_expires(period_timer); 104 delta = ktime_to_ns(ktime_sub(hard, soft)); 105 __hrtimer_start_range_ns(period_timer, soft, delta, 106 HRTIMER_MODE_ABS_PINNED, 0); 107 } 108} 109 110DEFINE_MUTEX(sched_domains_mutex); 111DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); 112 113static void update_rq_clock_task(struct rq *rq, s64 delta); 114 115void update_rq_clock(struct rq *rq) 116{ 117 s64 delta; 118 119 if (rq->skip_clock_update > 0) 120 return; 121 122 delta = sched_clock_cpu(cpu_of(rq)) - rq->clock; 123 rq->clock += delta; 124 update_rq_clock_task(rq, delta); 125} 126 127/* 128 * Debugging: various feature bits 129 */ 130 131#define SCHED_FEAT(name, enabled) \ 132 (1UL << __SCHED_FEAT_##name) * enabled | 133 134const_debug unsigned int sysctl_sched_features = 135#include "features.h" 136 0; 137 138#undef SCHED_FEAT 139 140#ifdef CONFIG_SCHED_DEBUG 141#define SCHED_FEAT(name, enabled) \ 142 #name , 143 144static __read_mostly char *sched_feat_names[] = { 145#include "features.h" 146 NULL 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) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG) 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 695void update_cpu_load(struct rq *this_rq); 696 697static void set_load_weight(struct task_struct *p) 698{ 699 int prio = p->static_prio - MAX_RT_PRIO; 700 struct load_weight *load = &p->se.load; 701 702 /* 703 * SCHED_IDLE tasks get minimal weight: 704 */ 705 if (p->policy == SCHED_IDLE) { 706 load->weight = scale_load(WEIGHT_IDLEPRIO); 707 load->inv_weight = WMULT_IDLEPRIO; 708 return; 709 } 710 711 load->weight = scale_load(prio_to_weight[prio]); 712 load->inv_weight = prio_to_wmult[prio]; 713} 714 715static void enqueue_task(struct rq *rq, struct task_struct *p, int flags) 716{ 717 update_rq_clock(rq); 718 sched_info_queued(p); 719 p->sched_class->enqueue_task(rq, p, flags); 720} 721 722static void dequeue_task(struct rq *rq, struct task_struct *p, int flags) 723{ 724 update_rq_clock(rq); 725 sched_info_dequeued(p); 726 p->sched_class->dequeue_task(rq, p, flags); 727} 728 729void activate_task(struct rq *rq, struct task_struct *p, int flags) 730{ 731 if (task_contributes_to_load(p)) 732 rq->nr_uninterruptible--; 733 734 enqueue_task(rq, p, flags); 735} 736 737void deactivate_task(struct rq *rq, struct task_struct *p, int flags) 738{ 739 if (task_contributes_to_load(p)) 740 rq->nr_uninterruptible++; 741 742 dequeue_task(rq, p, flags); 743} 744 745#ifdef CONFIG_IRQ_TIME_ACCOUNTING 746 747/* 748 * There are no locks covering percpu hardirq/softirq time. 749 * They are only modified in account_system_vtime, on corresponding CPU 750 * with interrupts disabled. So, writes are safe. 751 * They are read and saved off onto struct rq in update_rq_clock(). 752 * This may result in other CPU reading this CPU's irq time and can 753 * race with irq/account_system_vtime on this CPU. We would either get old 754 * or new value with a side effect of accounting a slice of irq time to wrong 755 * task when irq is in progress while we read rq->clock. That is a worthy 756 * compromise in place of having locks on each irq in account_system_time. 757 */ 758static DEFINE_PER_CPU(u64, cpu_hardirq_time); 759static DEFINE_PER_CPU(u64, cpu_softirq_time); 760 761static DEFINE_PER_CPU(u64, irq_start_time); 762static int sched_clock_irqtime; 763 764void enable_sched_clock_irqtime(void) 765{ 766 sched_clock_irqtime = 1; 767} 768 769void disable_sched_clock_irqtime(void) 770{ 771 sched_clock_irqtime = 0; 772} 773 774#ifndef CONFIG_64BIT 775static DEFINE_PER_CPU(seqcount_t, irq_time_seq); 776 777static inline void irq_time_write_begin(void) 778{ 779 __this_cpu_inc(irq_time_seq.sequence); 780 smp_wmb(); 781} 782 783static inline void irq_time_write_end(void) 784{ 785 smp_wmb(); 786 __this_cpu_inc(irq_time_seq.sequence); 787} 788 789static inline u64 irq_time_read(int cpu) 790{ 791 u64 irq_time; 792 unsigned seq; 793 794 do { 795 seq = read_seqcount_begin(&per_cpu(irq_time_seq, cpu)); 796 irq_time = per_cpu(cpu_softirq_time, cpu) + 797 per_cpu(cpu_hardirq_time, cpu); 798 } while (read_seqcount_retry(&per_cpu(irq_time_seq, cpu), seq)); 799 800 return irq_time; 801} 802#else /* CONFIG_64BIT */ 803static inline void irq_time_write_begin(void) 804{ 805} 806 807static inline void irq_time_write_end(void) 808{ 809} 810 811static inline u64 irq_time_read(int cpu) 812{ 813 return per_cpu(cpu_softirq_time, cpu) + per_cpu(cpu_hardirq_time, cpu); 814} 815#endif /* CONFIG_64BIT */ 816 817/* 818 * Called before incrementing preempt_count on {soft,}irq_enter 819 * and before decrementing preempt_count on {soft,}irq_exit. 820 */ 821void account_system_vtime(struct task_struct *curr) 822{ 823 unsigned long flags; 824 s64 delta; 825 int cpu; 826 827 if (!sched_clock_irqtime) 828 return; 829 830 local_irq_save(flags); 831 832 cpu = smp_processor_id(); 833 delta = sched_clock_cpu(cpu) - __this_cpu_read(irq_start_time); 834 __this_cpu_add(irq_start_time, delta); 835 836 irq_time_write_begin(); 837 /* 838 * We do not account for softirq time from ksoftirqd here. 839 * We want to continue accounting softirq time to ksoftirqd thread 840 * in that case, so as not to confuse scheduler with a special task 841 * that do not consume any time, but still wants to run. 842 */ 843 if (hardirq_count()) 844 __this_cpu_add(cpu_hardirq_time, delta); 845 else if (in_serving_softirq() && curr != this_cpu_ksoftirqd()) 846 __this_cpu_add(cpu_softirq_time, delta); 847 848 irq_time_write_end(); 849 local_irq_restore(flags); 850} 851EXPORT_SYMBOL_GPL(account_system_vtime); 852 853#endif /* CONFIG_IRQ_TIME_ACCOUNTING */ 854 855#ifdef CONFIG_PARAVIRT 856static inline u64 steal_ticks(u64 steal) 857{ 858 if (unlikely(steal > NSEC_PER_SEC)) 859 return div_u64(steal, TICK_NSEC); 860 861 return __iter_div_u64_rem(steal, TICK_NSEC, &steal); 862} 863#endif 864 865static void update_rq_clock_task(struct rq *rq, s64 delta) 866{ 867/* 868 * In theory, the compile should just see 0 here, and optimize out the call 869 * to sched_rt_avg_update. But I don't trust it... 870 */ 871#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) 872 s64 steal = 0, irq_delta = 0; 873#endif 874#ifdef CONFIG_IRQ_TIME_ACCOUNTING 875 irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time; 876 877 /* 878 * Since irq_time is only updated on {soft,}irq_exit, we might run into 879 * this case when a previous update_rq_clock() happened inside a 880 * {soft,}irq region. 881 * 882 * When this happens, we stop ->clock_task and only update the 883 * prev_irq_time stamp to account for the part that fit, so that a next 884 * update will consume the rest. This ensures ->clock_task is 885 * monotonic. 886 * 887 * It does however cause some slight miss-attribution of {soft,}irq 888 * time, a more accurate solution would be to update the irq_time using 889 * the current rq->clock timestamp, except that would require using 890 * atomic ops. 891 */ 892 if (irq_delta > delta) 893 irq_delta = delta; 894 895 rq->prev_irq_time += irq_delta; 896 delta -= irq_delta; 897#endif 898#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING 899 if (static_key_false((¶virt_steal_rq_enabled))) { 900 u64 st; 901 902 steal = paravirt_steal_clock(cpu_of(rq)); 903 steal -= rq->prev_steal_time_rq; 904 905 if (unlikely(steal > delta)) 906 steal = delta; 907 908 st = steal_ticks(steal); 909 steal = st * TICK_NSEC; 910 911 rq->prev_steal_time_rq += steal; 912 913 delta -= steal; 914 } 915#endif 916 917 rq->clock_task += delta; 918 919#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) 920 if ((irq_delta + steal) && sched_feat(NONTASK_POWER)) 921 sched_rt_avg_update(rq, irq_delta + steal); 922#endif 923} 924 925#ifdef CONFIG_IRQ_TIME_ACCOUNTING 926static int irqtime_account_hi_update(void) 927{ 928 u64 *cpustat = kcpustat_this_cpu->cpustat; 929 unsigned long flags; 930 u64 latest_ns; 931 int ret = 0; 932 933 local_irq_save(flags); 934 latest_ns = this_cpu_read(cpu_hardirq_time); 935 if (nsecs_to_cputime64(latest_ns) > cpustat[CPUTIME_IRQ]) 936 ret = 1; 937 local_irq_restore(flags); 938 return ret; 939} 940 941static int irqtime_account_si_update(void) 942{ 943 u64 *cpustat = kcpustat_this_cpu->cpustat; 944 unsigned long flags; 945 u64 latest_ns; 946 int ret = 0; 947 948 local_irq_save(flags); 949 latest_ns = this_cpu_read(cpu_softirq_time); 950 if (nsecs_to_cputime64(latest_ns) > cpustat[CPUTIME_SOFTIRQ]) 951 ret = 1; 952 local_irq_restore(flags); 953 return ret; 954} 955 956#else /* CONFIG_IRQ_TIME_ACCOUNTING */ 957 958#define sched_clock_irqtime (0) 959 960#endif 961 962void sched_set_stop_task(int cpu, struct task_struct *stop) 963{ 964 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 }; 965 struct task_struct *old_stop = cpu_rq(cpu)->stop; 966 967 if (stop) { 968 /* 969 * Make it appear like a SCHED_FIFO task, its something 970 * userspace knows about and won't get confused about. 971 * 972 * Also, it will make PI more or less work without too 973 * much confusion -- but then, stop work should not 974 * rely on PI working anyway. 975 */ 976 sched_setscheduler_nocheck(stop, SCHED_FIFO, ¶m); 977 978 stop->sched_class = &stop_sched_class; 979 } 980 981 cpu_rq(cpu)->stop = stop; 982 983 if (old_stop) { 984 /* 985 * Reset it back to a normal scheduling class so that 986 * it can die in pieces. 987 */ 988 old_stop->sched_class = &rt_sched_class; 989 } 990} 991 992/* 993 * __normal_prio - return the priority that is based on the static prio 994 */ 995static inline int __normal_prio(struct task_struct *p) 996{ 997 return p->static_prio; 998} 999 1000/* 1001 * Calculate the expected normal priority: i.e. priority 1002 * without taking RT-inheritance into account. Might be 1003 * boosted by interactivity modifiers. Changes upon fork, 1004 * setprio syscalls, and whenever the interactivity 1005 * estimator recalculates. 1006 */ 1007static inline int normal_prio(struct task_struct *p) 1008{ 1009 int prio; 1010 1011 if (task_has_rt_policy(p)) 1012 prio = MAX_RT_PRIO-1 - p->rt_priority; 1013 else 1014 prio = __normal_prio(p); 1015 return prio; 1016} 1017 1018/* 1019 * Calculate the current priority, i.e. the priority 1020 * taken into account by the scheduler. This value might 1021 * be boosted by RT tasks, or might be boosted by 1022 * interactivity modifiers. Will be RT if the task got 1023 * RT-boosted. If not then it returns p->normal_prio. 1024 */ 1025static int effective_prio(struct task_struct *p) 1026{ 1027 p->normal_prio = normal_prio(p); 1028 /* 1029 * If we are RT tasks or we were boosted to RT priority, 1030 * keep the priority unchanged. Otherwise, update priority 1031 * to the normal priority: 1032 */ 1033 if (!rt_prio(p->prio)) 1034 return p->normal_prio; 1035 return p->prio; 1036} 1037 1038/** 1039 * task_curr - is this task currently executing on a CPU? 1040 * @p: the task in question. 1041 */ 1042inline int task_curr(const struct task_struct *p) 1043{ 1044 return cpu_curr(task_cpu(p)) == p; 1045} 1046 1047static inline void check_class_changed(struct rq *rq, struct task_struct *p, 1048 const struct sched_class *prev_class, 1049 int oldprio) 1050{ 1051 if (prev_class != p->sched_class) { 1052 if (prev_class->switched_from) 1053 prev_class->switched_from(rq, p); 1054 p->sched_class->switched_to(rq, p); 1055 } else if (oldprio != p->prio) 1056 p->sched_class->prio_changed(rq, p, oldprio); 1057} 1058 1059void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags) 1060{ 1061 const struct sched_class *class; 1062 1063 if (p->sched_class == rq->curr->sched_class) { 1064 rq->curr->sched_class->check_preempt_curr(rq, p, flags); 1065 } else { 1066 for_each_class(class) { 1067 if (class == rq->curr->sched_class) 1068 break; 1069 if (class == p->sched_class) { 1070 resched_task(rq->curr); 1071 break; 1072 } 1073 } 1074 } 1075 1076 /* 1077 * A queue event has occurred, and we're going to schedule. In 1078 * this case, we can save a useless back to back clock update. 1079 */ 1080 if (rq->curr->on_rq && test_tsk_need_resched(rq->curr)) 1081 rq->skip_clock_update = 1; 1082} 1083 1084#ifdef CONFIG_SMP 1085void set_task_cpu(struct task_struct *p, unsigned int new_cpu) 1086{ 1087#ifdef CONFIG_SCHED_DEBUG 1088 /* 1089 * We should never call set_task_cpu() on a blocked task, 1090 * ttwu() will sort out the placement. 1091 */ 1092 WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING && 1093 !(task_thread_info(p)->preempt_count & PREEMPT_ACTIVE)); 1094 1095#ifdef CONFIG_LOCKDEP 1096 /* 1097 * The caller should hold either p->pi_lock or rq->lock, when changing 1098 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks. 1099 * 1100 * sched_move_task() holds both and thus holding either pins the cgroup, 1101 * see set_task_rq(). 1102 * 1103 * Furthermore, all task_rq users should acquire both locks, see 1104 * task_rq_lock(). 1105 */ 1106 WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) || 1107 lockdep_is_held(&task_rq(p)->lock))); 1108#endif 1109#endif 1110 1111 trace_sched_migrate_task(p, new_cpu); 1112 1113 if (task_cpu(p) != new_cpu) { 1114 p->se.nr_migrations++; 1115 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, 1, NULL, 0); 1116 } 1117 1118 __set_task_cpu(p, new_cpu); 1119} 1120 1121struct migration_arg { 1122 struct task_struct *task; 1123 int dest_cpu; 1124}; 1125 1126static int migration_cpu_stop(void *data); 1127 1128/* 1129 * wait_task_inactive - wait for a thread to unschedule. 1130 * 1131 * If @match_state is nonzero, it's the @p->state value just checked and 1132 * not expected to change. If it changes, i.e. @p might have woken up, 1133 * then return zero. When we succeed in waiting for @p to be off its CPU, 1134 * we return a positive number (its total switch count). If a second call 1135 * a short while later returns the same number, the caller can be sure that 1136 * @p has remained unscheduled the whole time. 1137 * 1138 * The caller must ensure that the task *will* unschedule sometime soon, 1139 * else this function might spin for a *long* time. This function can't 1140 * be called with interrupts off, or it may introduce deadlock with 1141 * smp_call_function() if an IPI is sent by the same process we are 1142 * waiting to become inactive. 1143 */ 1144unsigned long wait_task_inactive(struct task_struct *p, long match_state) 1145{ 1146 unsigned long flags; 1147 int running, on_rq; 1148 unsigned long ncsw; 1149 struct rq *rq; 1150 1151 for (;;) { 1152 /* 1153 * We do the initial early heuristics without holding 1154 * any task-queue locks at all. We'll only try to get 1155 * the runqueue lock when things look like they will 1156 * work out! 1157 */ 1158 rq = task_rq(p); 1159 1160 /* 1161 * If the task is actively running on another CPU 1162 * still, just relax and busy-wait without holding 1163 * any locks. 1164 * 1165 * NOTE! Since we don't hold any locks, it's not 1166 * even sure that "rq" stays as the right runqueue! 1167 * But we don't care, since "task_running()" will 1168 * return false if the runqueue has changed and p 1169 * is actually now running somewhere else! 1170 */ 1171 while (task_running(rq, p)) { 1172 if (match_state && unlikely(p->state != match_state)) 1173 return 0; 1174 cpu_relax(); 1175 } 1176 1177 /* 1178 * Ok, time to look more closely! We need the rq 1179 * lock now, to be *sure*. If we're wrong, we'll 1180 * just go back and repeat. 1181 */ 1182 rq = task_rq_lock(p, &flags); 1183 trace_sched_wait_task(p); 1184 running = task_running(rq, p); 1185 on_rq = p->on_rq; 1186 ncsw = 0; 1187 if (!match_state || p->state == match_state) 1188 ncsw = p->nvcsw | LONG_MIN; /* sets MSB */ 1189 task_rq_unlock(rq, p, &flags); 1190 1191 /* 1192 * If it changed from the expected state, bail out now. 1193 */ 1194 if (unlikely(!ncsw)) 1195 break; 1196 1197 /* 1198 * Was it really running after all now that we 1199 * checked with the proper locks actually held? 1200 * 1201 * Oops. Go back and try again.. 1202 */ 1203 if (unlikely(running)) { 1204 cpu_relax(); 1205 continue; 1206 } 1207 1208 /* 1209 * It's not enough that it's not actively running, 1210 * it must be off the runqueue _entirely_, and not 1211 * preempted! 1212 * 1213 * So if it was still runnable (but just not actively 1214 * running right now), it's preempted, and we should 1215 * yield - it could be a while. 1216 */ 1217 if (unlikely(on_rq)) { 1218 ktime_t to = ktime_set(0, NSEC_PER_SEC/HZ); 1219 1220 set_current_state(TASK_UNINTERRUPTIBLE); 1221 schedule_hrtimeout(&to, HRTIMER_MODE_REL); 1222 continue; 1223 } 1224 1225 /* 1226 * Ahh, all good. It wasn't running, and it wasn't 1227 * runnable, which means that it will never become 1228 * running in the future either. We're all done! 1229 */ 1230 break; 1231 } 1232 1233 return ncsw; 1234} 1235 1236/*** 1237 * kick_process - kick a running thread to enter/exit the kernel 1238 * @p: the to-be-kicked thread 1239 * 1240 * Cause a process which is running on another CPU to enter 1241 * kernel-mode, without any delay. (to get signals handled.) 1242 * 1243 * NOTE: this function doesn't have to take the runqueue lock, 1244 * because all it wants to ensure is that the remote task enters 1245 * the kernel. If the IPI races and the task has been migrated 1246 * to another CPU then no harm is done and the purpose has been 1247 * achieved as well. 1248 */ 1249void kick_process(struct task_struct *p) 1250{ 1251 int cpu; 1252 1253 preempt_disable(); 1254 cpu = task_cpu(p); 1255 if ((cpu != smp_processor_id()) && task_curr(p)) 1256 smp_send_reschedule(cpu); 1257 preempt_enable(); 1258} 1259EXPORT_SYMBOL_GPL(kick_process); 1260#endif /* CONFIG_SMP */ 1261 1262#ifdef CONFIG_SMP 1263/* 1264 * ->cpus_allowed is protected by both rq->lock and p->pi_lock 1265 */ 1266static int select_fallback_rq(int cpu, struct task_struct *p) 1267{ 1268 const struct cpumask *nodemask = cpumask_of_node(cpu_to_node(cpu)); 1269 enum { cpuset, possible, fail } state = cpuset; 1270 int dest_cpu; 1271 1272 /* Look for allowed, online CPU in same node. */ 1273 for_each_cpu(dest_cpu, nodemask) { 1274 if (!cpu_online(dest_cpu)) 1275 continue; 1276 if (!cpu_active(dest_cpu)) 1277 continue; 1278 if (cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) 1279 return dest_cpu; 1280 } 1281 1282 for (;;) { 1283 /* Any allowed, online CPU? */ 1284 for_each_cpu(dest_cpu, tsk_cpus_allowed(p)) { 1285 if (!cpu_online(dest_cpu)) 1286 continue; 1287 if (!cpu_active(dest_cpu)) 1288 continue; 1289 goto out; 1290 } 1291 1292 switch (state) { 1293 case cpuset: 1294 /* No more Mr. Nice Guy. */ 1295 cpuset_cpus_allowed_fallback(p); 1296 state = possible; 1297 break; 1298 1299 case possible: 1300 do_set_cpus_allowed(p, cpu_possible_mask); 1301 state = fail; 1302 break; 1303 1304 case fail: 1305 BUG(); 1306 break; 1307 } 1308 } 1309 1310out: 1311 if (state != cpuset) { 1312 /* 1313 * Don't tell them about moving exiting tasks or 1314 * kernel threads (both mm NULL), since they never 1315 * leave kernel. 1316 */ 1317 if (p->mm && printk_ratelimit()) { 1318 printk_sched("process %d (%s) no longer affine to cpu%d\n", 1319 task_pid_nr(p), p->comm, cpu); 1320 } 1321 } 1322 1323 return dest_cpu; 1324} 1325 1326/* 1327 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable. 1328 */ 1329static inline 1330int select_task_rq(struct task_struct *p, int sd_flags, int wake_flags) 1331{ 1332 int cpu = p->sched_class->select_task_rq(p, sd_flags, wake_flags); 1333 1334 /* 1335 * In order not to call set_task_cpu() on a blocking task we need 1336 * to rely on ttwu() to place the task on a valid ->cpus_allowed 1337 * cpu. 1338 * 1339 * Since this is common to all placement strategies, this lives here. 1340 * 1341 * [ this allows ->select_task() to simply return task_cpu(p) and 1342 * not worry about this generic constraint ] 1343 */ 1344 if (unlikely(!cpumask_test_cpu(cpu, tsk_cpus_allowed(p)) || 1345 !cpu_online(cpu))) 1346 cpu = select_fallback_rq(task_cpu(p), p); 1347 1348 return cpu; 1349} 1350 1351static void update_avg(u64 *avg, u64 sample) 1352{ 1353 s64 diff = sample - *avg; 1354 *avg += diff >> 3; 1355} 1356#endif 1357 1358static void 1359ttwu_stat(struct task_struct *p, int cpu, int wake_flags) 1360{ 1361#ifdef CONFIG_SCHEDSTATS 1362 struct rq *rq = this_rq(); 1363 1364#ifdef CONFIG_SMP 1365 int this_cpu = smp_processor_id(); 1366 1367 if (cpu == this_cpu) { 1368 schedstat_inc(rq, ttwu_local); 1369 schedstat_inc(p, se.statistics.nr_wakeups_local); 1370 } else { 1371 struct sched_domain *sd; 1372 1373 schedstat_inc(p, se.statistics.nr_wakeups_remote); 1374 rcu_read_lock(); 1375 for_each_domain(this_cpu, sd) { 1376 if (cpumask_test_cpu(cpu, sched_domain_span(sd))) { 1377 schedstat_inc(sd, ttwu_wake_remote); 1378 break; 1379 } 1380 } 1381 rcu_read_unlock(); 1382 } 1383 1384 if (wake_flags & WF_MIGRATED) 1385 schedstat_inc(p, se.statistics.nr_wakeups_migrate); 1386 1387#endif /* CONFIG_SMP */ 1388 1389 schedstat_inc(rq, ttwu_count); 1390 schedstat_inc(p, se.statistics.nr_wakeups); 1391 1392 if (wake_flags & WF_SYNC) 1393 schedstat_inc(p, se.statistics.nr_wakeups_sync); 1394 1395#endif /* CONFIG_SCHEDSTATS */ 1396} 1397 1398static void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags) 1399{ 1400 activate_task(rq, p, en_flags); 1401 p->on_rq = 1; 1402 1403 /* if a worker is waking up, notify workqueue */ 1404 if (p->flags & PF_WQ_WORKER) 1405 wq_worker_waking_up(p, cpu_of(rq)); 1406} 1407 1408/* 1409 * Mark the task runnable and perform wakeup-preemption. 1410 */ 1411static void 1412ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags) 1413{ 1414 trace_sched_wakeup(p, true); 1415 check_preempt_curr(rq, p, wake_flags); 1416 1417 p->state = TASK_RUNNING; 1418#ifdef CONFIG_SMP 1419 if (p->sched_class->task_woken) 1420 p->sched_class->task_woken(rq, p); 1421 1422 if (rq->idle_stamp) { 1423 u64 delta = rq->clock - rq->idle_stamp; 1424 u64 max = 2*sysctl_sched_migration_cost; 1425 1426 if (delta > max) 1427 rq->avg_idle = max; 1428 else 1429 update_avg(&rq->avg_idle, delta); 1430 rq->idle_stamp = 0; 1431 } 1432#endif 1433} 1434 1435static void 1436ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags) 1437{ 1438#ifdef CONFIG_SMP 1439 if (p->sched_contributes_to_load) 1440 rq->nr_uninterruptible--; 1441#endif 1442 1443 ttwu_activate(rq, p, ENQUEUE_WAKEUP | ENQUEUE_WAKING); 1444 ttwu_do_wakeup(rq, p, wake_flags); 1445} 1446 1447/* 1448 * Called in case the task @p isn't fully descheduled from its runqueue, 1449 * in this case we must do a remote wakeup. Its a 'light' wakeup though, 1450 * since all we need to do is flip p->state to TASK_RUNNING, since 1451 * the task is still ->on_rq. 1452 */ 1453static int ttwu_remote(struct task_struct *p, int wake_flags) 1454{ 1455 struct rq *rq; 1456 int ret = 0; 1457 1458 rq = __task_rq_lock(p); 1459 if (p->on_rq) { 1460 ttwu_do_wakeup(rq, p, wake_flags); 1461 ret = 1; 1462 } 1463 __task_rq_unlock(rq); 1464 1465 return ret; 1466} 1467 1468#ifdef CONFIG_SMP 1469static void sched_ttwu_pending(void) 1470{ 1471 struct rq *rq = this_rq(); 1472 struct llist_node *llist = llist_del_all(&rq->wake_list); 1473 struct task_struct *p; 1474 1475 raw_spin_lock(&rq->lock); 1476 1477 while (llist) { 1478 p = llist_entry(llist, struct task_struct, wake_entry); 1479 llist = llist_next(llist); 1480 ttwu_do_activate(rq, p, 0); 1481 } 1482 1483 raw_spin_unlock(&rq->lock); 1484} 1485 1486void scheduler_ipi(void) 1487{ 1488 if (llist_empty(&this_rq()->wake_list) && !got_nohz_idle_kick()) 1489 return; 1490 1491 /* 1492 * Not all reschedule IPI handlers call irq_enter/irq_exit, since 1493 * traditionally all their work was done from the interrupt return 1494 * path. Now that we actually do some work, we need to make sure 1495 * we do call them. 1496 * 1497 * Some archs already do call them, luckily irq_enter/exit nest 1498 * properly. 1499 * 1500 * Arguably we should visit all archs and update all handlers, 1501 * however a fair share of IPIs are still resched only so this would 1502 * somewhat pessimize the simple resched case. 1503 */ 1504 irq_enter(); 1505 sched_ttwu_pending(); 1506 1507 /* 1508 * Check if someone kicked us for doing the nohz idle load balance. 1509 */ 1510 if (unlikely(got_nohz_idle_kick() && !need_resched())) { 1511 this_rq()->idle_balance = 1; 1512 raise_softirq_irqoff(SCHED_SOFTIRQ); 1513 } 1514 irq_exit(); 1515} 1516 1517static void ttwu_queue_remote(struct task_struct *p, int cpu) 1518{ 1519 if (llist_add(&p->wake_entry, &cpu_rq(cpu)->wake_list)) 1520 smp_send_reschedule(cpu); 1521} 1522 1523#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW 1524static int ttwu_activate_remote(struct task_struct *p, int wake_flags) 1525{ 1526 struct rq *rq; 1527 int ret = 0; 1528 1529 rq = __task_rq_lock(p); 1530 if (p->on_cpu) { 1531 ttwu_activate(rq, p, ENQUEUE_WAKEUP); 1532 ttwu_do_wakeup(rq, p, wake_flags); 1533 ret = 1; 1534 } 1535 __task_rq_unlock(rq); 1536 1537 return ret; 1538 1539} 1540#endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */ 1541 1542bool cpus_share_cache(int this_cpu, int that_cpu) 1543{ 1544 return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu); 1545} 1546#endif /* CONFIG_SMP */ 1547 1548static void ttwu_queue(struct task_struct *p, int cpu) 1549{ 1550 struct rq *rq = cpu_rq(cpu); 1551 1552#if defined(CONFIG_SMP) 1553 if (sched_feat(TTWU_QUEUE) && !cpus_share_cache(smp_processor_id(), cpu)) { 1554 sched_clock_cpu(cpu); /* sync clocks x-cpu */ 1555 ttwu_queue_remote(p, cpu); 1556 return; 1557 } 1558#endif 1559 1560 raw_spin_lock(&rq->lock); 1561 ttwu_do_activate(rq, p, 0); 1562 raw_spin_unlock(&rq->lock); 1563} 1564 1565/** 1566 * try_to_wake_up - wake up a thread 1567 * @p: the thread to be awakened 1568 * @state: the mask of task states that can be woken 1569 * @wake_flags: wake modifier flags (WF_*) 1570 * 1571 * Put it on the run-queue if it's not already there. The "current" 1572 * thread is always on the run-queue (except when the actual 1573 * re-schedule is in progress), and as such you're allowed to do 1574 * the simpler "current->state = TASK_RUNNING" to mark yourself 1575 * runnable without the overhead of this. 1576 * 1577 * Returns %true if @p was woken up, %false if it was already running 1578 * or @state didn't match @p's state. 1579 */ 1580static int 1581try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) 1582{ 1583 unsigned long flags; 1584 int cpu, success = 0; 1585 1586 smp_wmb(); 1587 raw_spin_lock_irqsave(&p->pi_lock, flags); 1588 if (!(p->state & state)) 1589 goto out; 1590 1591 success = 1; /* we're going to change ->state */ 1592 cpu = task_cpu(p); 1593 1594 if (p->on_rq && ttwu_remote(p, wake_flags)) 1595 goto stat; 1596 1597#ifdef CONFIG_SMP 1598 /* 1599 * If the owning (remote) cpu is still in the middle of schedule() with 1600 * this task as prev, wait until its done referencing the task. 1601 */ 1602 while (p->on_cpu) { 1603#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW 1604 /* 1605 * In case the architecture enables interrupts in 1606 * context_switch(), we cannot busy wait, since that 1607 * would lead to deadlocks when an interrupt hits and 1608 * tries to wake up @prev. So bail and do a complete 1609 * remote wakeup. 1610 */ 1611 if (ttwu_activate_remote(p, wake_flags)) 1612 goto stat; 1613#else 1614 cpu_relax(); 1615#endif 1616 } 1617 /* 1618 * Pairs with the smp_wmb() in finish_lock_switch(). 1619 */ 1620 smp_rmb(); 1621 1622 p->sched_contributes_to_load = !!task_contributes_to_load(p); 1623 p->state = TASK_WAKING; 1624 1625 if (p->sched_class->task_waking) 1626 p->sched_class->task_waking(p); 1627 1628 cpu = select_task_rq(p, SD_BALANCE_WAKE, wake_flags); 1629 if (task_cpu(p) != cpu) { 1630 wake_flags |= WF_MIGRATED; 1631 set_task_cpu(p, cpu); 1632 } 1633#endif /* CONFIG_SMP */ 1634 1635 ttwu_queue(p, cpu); 1636stat: 1637 ttwu_stat(p, cpu, wake_flags); 1638out: 1639 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 1640 1641 return success; 1642} 1643 1644/** 1645 * try_to_wake_up_local - try to wake up a local task with rq lock held 1646 * @p: the thread to be awakened 1647 * 1648 * Put @p on the run-queue if it's not already there. The caller must 1649 * ensure that this_rq() is locked, @p is bound to this_rq() and not 1650 * the current task. 1651 */ 1652static void try_to_wake_up_local(struct task_struct *p) 1653{ 1654 struct rq *rq = task_rq(p); 1655 1656 BUG_ON(rq != this_rq()); 1657 BUG_ON(p == current); 1658 lockdep_assert_held(&rq->lock); 1659 1660 if (!raw_spin_trylock(&p->pi_lock)) { 1661 raw_spin_unlock(&rq->lock); 1662 raw_spin_lock(&p->pi_lock); 1663 raw_spin_lock(&rq->lock); 1664 } 1665 1666 if (!(p->state & TASK_NORMAL)) 1667 goto out; 1668 1669 if (!p->on_rq) 1670 ttwu_activate(rq, p, ENQUEUE_WAKEUP); 1671 1672 ttwu_do_wakeup(rq, p, 0); 1673 ttwu_stat(p, smp_processor_id(), 0); 1674out: 1675 raw_spin_unlock(&p->pi_lock); 1676} 1677 1678/** 1679 * wake_up_process - Wake up a specific process 1680 * @p: The process to be woken up. 1681 * 1682 * Attempt to wake up the nominated process and move it to the set of runnable 1683 * processes. Returns 1 if the process was woken up, 0 if it was already 1684 * running. 1685 * 1686 * It may be assumed that this function implies a write memory barrier before 1687 * changing the task state if and only if any tasks are woken up. 1688 */ 1689int wake_up_process(struct task_struct *p) 1690{ 1691 return try_to_wake_up(p, TASK_ALL, 0); 1692} 1693EXPORT_SYMBOL(wake_up_process); 1694 1695int wake_up_state(struct task_struct *p, unsigned int state) 1696{ 1697 return try_to_wake_up(p, state, 0); 1698} 1699 1700/* 1701 * Perform scheduler related setup for a newly forked process p. 1702 * p is forked by current. 1703 * 1704 * __sched_fork() is basic setup used by init_idle() too: 1705 */ 1706static void __sched_fork(struct task_struct *p) 1707{ 1708 p->on_rq = 0; 1709 1710 p->se.on_rq = 0; 1711 p->se.exec_start = 0; 1712 p->se.sum_exec_runtime = 0; 1713 p->se.prev_sum_exec_runtime = 0; 1714 p->se.nr_migrations = 0; 1715 p->se.vruntime = 0; 1716 INIT_LIST_HEAD(&p->se.group_node); 1717 1718#ifdef CONFIG_SCHEDSTATS 1719 memset(&p->se.statistics, 0, sizeof(p->se.statistics)); 1720#endif 1721 1722 INIT_LIST_HEAD(&p->rt.run_list); 1723 1724#ifdef CONFIG_PREEMPT_NOTIFIERS 1725 INIT_HLIST_HEAD(&p->preempt_notifiers); 1726#endif 1727} 1728 1729/* 1730 * fork()/clone()-time setup: 1731 */ 1732void sched_fork(struct task_struct *p) 1733{ 1734 unsigned long flags; 1735 int cpu = get_cpu(); 1736 1737 __sched_fork(p); 1738 /* 1739 * We mark the process as running here. This guarantees that 1740 * nobody will actually run it, and a signal or other external 1741 * event cannot wake it up and insert it on the runqueue either. 1742 */ 1743 p->state = TASK_RUNNING; 1744 1745 /* 1746 * Make sure we do not leak PI boosting priority to the child. 1747 */ 1748 p->prio = current->normal_prio; 1749 1750 /* 1751 * Revert to default priority/policy on fork if requested. 1752 */ 1753 if (unlikely(p->sched_reset_on_fork)) { 1754 if (task_has_rt_policy(p)) { 1755 p->policy = SCHED_NORMAL; 1756 p->static_prio = NICE_TO_PRIO(0); 1757 p->rt_priority = 0; 1758 } else if (PRIO_TO_NICE(p->static_prio) < 0) 1759 p->static_prio = NICE_TO_PRIO(0); 1760 1761 p->prio = p->normal_prio = __normal_prio(p); 1762 set_load_weight(p); 1763 1764 /* 1765 * We don't need the reset flag anymore after the fork. It has 1766 * fulfilled its duty: 1767 */ 1768 p->sched_reset_on_fork = 0; 1769 } 1770 1771 if (!rt_prio(p->prio)) 1772 p->sched_class = &fair_sched_class; 1773 1774 if (p->sched_class->task_fork) 1775 p->sched_class->task_fork(p); 1776 1777 /* 1778 * The child is not yet in the pid-hash so no cgroup attach races, 1779 * and the cgroup is pinned to this child due to cgroup_fork() 1780 * is ran before sched_fork(). 1781 * 1782 * Silence PROVE_RCU. 1783 */ 1784 raw_spin_lock_irqsave(&p->pi_lock, flags); 1785 set_task_cpu(p, cpu); 1786 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 1787 1788#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) 1789 if (likely(sched_info_on())) 1790 memset(&p->sched_info, 0, sizeof(p->sched_info)); 1791#endif 1792#if defined(CONFIG_SMP) 1793 p->on_cpu = 0; 1794#endif 1795#ifdef CONFIG_PREEMPT_COUNT 1796 /* Want to start with kernel preemption disabled. */ 1797 task_thread_info(p)->preempt_count = 1; 1798#endif 1799#ifdef CONFIG_SMP 1800 plist_node_init(&p->pushable_tasks, MAX_PRIO); 1801#endif 1802 1803 put_cpu(); 1804} 1805 1806/* 1807 * wake_up_new_task - wake up a newly created task for the first time. 1808 * 1809 * This function will do some initial scheduler statistics housekeeping 1810 * that must be done for every newly created context, then puts the task 1811 * on the runqueue and wakes it. 1812 */ 1813void wake_up_new_task(struct task_struct *p) 1814{ 1815 unsigned long flags; 1816 struct rq *rq; 1817 1818 raw_spin_lock_irqsave(&p->pi_lock, flags); 1819#ifdef CONFIG_SMP 1820 /* 1821 * Fork balancing, do it here and not earlier because: 1822 * - cpus_allowed can change in the fork path 1823 * - any previously selected cpu might disappear through hotplug 1824 */ 1825 set_task_cpu(p, select_task_rq(p, SD_BALANCE_FORK, 0)); 1826#endif 1827 1828 rq = __task_rq_lock(p); 1829 activate_task(rq, p, 0); 1830 p->on_rq = 1; 1831 trace_sched_wakeup_new(p, true); 1832 check_preempt_curr(rq, p, WF_FORK); 1833#ifdef CONFIG_SMP 1834 if (p->sched_class->task_woken) 1835 p->sched_class->task_woken(rq, p); 1836#endif 1837 task_rq_unlock(rq, p, &flags); 1838} 1839 1840#ifdef CONFIG_PREEMPT_NOTIFIERS 1841 1842/** 1843 * preempt_notifier_register - tell me when current is being preempted & rescheduled 1844 * @notifier: notifier struct to register 1845 */ 1846void preempt_notifier_register(struct preempt_notifier *notifier) 1847{ 1848 hlist_add_head(¬ifier->link, ¤t->preempt_notifiers); 1849} 1850EXPORT_SYMBOL_GPL(preempt_notifier_register); 1851 1852/** 1853 * preempt_notifier_unregister - no longer interested in preemption notifications 1854 * @notifier: notifier struct to unregister 1855 * 1856 * This is safe to call from within a preemption notifier. 1857 */ 1858void preempt_notifier_unregister(struct preempt_notifier *notifier) 1859{ 1860 hlist_del(¬ifier->link); 1861} 1862EXPORT_SYMBOL_GPL(preempt_notifier_unregister); 1863 1864static void fire_sched_in_preempt_notifiers(struct task_struct *curr) 1865{ 1866 struct preempt_notifier *notifier; 1867 struct hlist_node *node; 1868 1869 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link) 1870 notifier->ops->sched_in(notifier, raw_smp_processor_id()); 1871} 1872 1873static void 1874fire_sched_out_preempt_notifiers(struct task_struct *curr, 1875 struct task_struct *next) 1876{ 1877 struct preempt_notifier *notifier; 1878 struct hlist_node *node; 1879 1880 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link) 1881 notifier->ops->sched_out(notifier, next); 1882} 1883 1884#else /* !CONFIG_PREEMPT_NOTIFIERS */ 1885 1886static void fire_sched_in_preempt_notifiers(struct task_struct *curr) 1887{ 1888} 1889 1890static void 1891fire_sched_out_preempt_notifiers(struct task_struct *curr, 1892 struct task_struct *next) 1893{ 1894} 1895 1896#endif /* CONFIG_PREEMPT_NOTIFIERS */ 1897 1898/** 1899 * prepare_task_switch - prepare to switch tasks 1900 * @rq: the runqueue preparing to switch 1901 * @prev: the current task that is being switched out 1902 * @next: the task we are going to switch to. 1903 * 1904 * This is called with the rq lock held and interrupts off. It must 1905 * be paired with a subsequent finish_task_switch after the context 1906 * switch. 1907 * 1908 * prepare_task_switch sets up locking and calls architecture specific 1909 * hooks. 1910 */ 1911static inline void 1912prepare_task_switch(struct rq *rq, struct task_struct *prev, 1913 struct task_struct *next) 1914{ 1915 sched_info_switch(prev, next); 1916 perf_event_task_sched_out(prev, next); 1917 fire_sched_out_preempt_notifiers(prev, next); 1918 prepare_lock_switch(rq, next); 1919 prepare_arch_switch(next); 1920 trace_sched_switch(prev, next); 1921} 1922 1923/** 1924 * finish_task_switch - clean up after a task-switch 1925 * @rq: runqueue associated with task-switch 1926 * @prev: the thread we just switched away from. 1927 * 1928 * finish_task_switch must be called after the context switch, paired 1929 * with a prepare_task_switch call before the context switch. 1930 * finish_task_switch will reconcile locking set up by prepare_task_switch, 1931 * and do any other architecture-specific cleanup actions. 1932 * 1933 * Note that we may have delayed dropping an mm in context_switch(). If 1934 * so, we finish that here outside of the runqueue lock. (Doing it 1935 * with the lock held can cause deadlocks; see schedule() for 1936 * details.) 1937 */ 1938static void finish_task_switch(struct rq *rq, struct task_struct *prev) 1939 __releases(rq->lock) 1940{ 1941 struct mm_struct *mm = rq->prev_mm; 1942 long prev_state; 1943 1944 rq->prev_mm = NULL; 1945 1946 /* 1947 * A task struct has one reference for the use as "current". 1948 * If a task dies, then it sets TASK_DEAD in tsk->state and calls 1949 * schedule one last time. The schedule call will never return, and 1950 * the scheduled task must drop that reference. 1951 * The test for TASK_DEAD must occur while the runqueue locks are 1952 * still held, otherwise prev could be scheduled on another cpu, die 1953 * there before we look at prev->state, and then the reference would 1954 * be dropped twice. 1955 * Manfred Spraul <manfred@colorfullife.com> 1956 */ 1957 prev_state = prev->state; 1958 finish_arch_switch(prev); 1959#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW 1960 local_irq_disable(); 1961#endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */ 1962 perf_event_task_sched_in(prev, current); 1963#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW 1964 local_irq_enable(); 1965#endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */ 1966 finish_lock_switch(rq, prev); 1967 finish_arch_post_lock_switch(); 1968 1969 fire_sched_in_preempt_notifiers(current); 1970 if (mm) 1971 mmdrop(mm); 1972 if (unlikely(prev_state == TASK_DEAD)) { 1973 /* 1974 * Remove function-return probe instances associated with this 1975 * task and put them back on the free list. 1976 */ 1977 kprobe_flush_task(prev); 1978 put_task_struct(prev); 1979 } 1980} 1981 1982#ifdef CONFIG_SMP 1983 1984/* assumes rq->lock is held */ 1985static inline void pre_schedule(struct rq *rq, struct task_struct *prev) 1986{ 1987 if (prev->sched_class->pre_schedule) 1988 prev->sched_class->pre_schedule(rq, prev); 1989} 1990 1991/* rq->lock is NOT held, but preemption is disabled */ 1992static inline void post_schedule(struct rq *rq) 1993{ 1994 if (rq->post_schedule) { 1995 unsigned long flags; 1996 1997 raw_spin_lock_irqsave(&rq->lock, flags); 1998 if (rq->curr->sched_class->post_schedule) 1999 rq->curr->sched_class->post_schedule(rq); 2000 raw_spin_unlock_irqrestore(&rq->lock, flags); 2001 2002 rq->post_schedule = 0; 2003 } 2004} 2005 2006#else 2007 2008static inline void pre_schedule(struct rq *rq, struct task_struct *p) 2009{ 2010} 2011 2012static inline void post_schedule(struct rq *rq) 2013{ 2014} 2015 2016#endif 2017 2018/** 2019 * schedule_tail - first thing a freshly forked thread must call. 2020 * @prev: the thread we just switched away from. 2021 */ 2022asmlinkage void schedule_tail(struct task_struct *prev) 2023 __releases(rq->lock) 2024{ 2025 struct rq *rq = this_rq(); 2026 2027 finish_task_switch(rq, prev); 2028 2029 /* 2030 * FIXME: do we need to worry about rq being invalidated by the 2031 * task_switch? 2032 */ 2033 post_schedule(rq); 2034 2035#ifdef __ARCH_WANT_UNLOCKED_CTXSW 2036 /* In this case, finish_task_switch does not reenable preemption */ 2037 preempt_enable(); 2038#endif 2039 if (current->set_child_tid) 2040 put_user(task_pid_vnr(current), current->set_child_tid); 2041} 2042 2043/* 2044 * context_switch - switch to the new MM and the new 2045 * thread's register state. 2046 */ 2047static inline void 2048context_switch(struct rq *rq, struct task_struct *prev, 2049 struct task_struct *next) 2050{ 2051 struct mm_struct *mm, *oldmm; 2052 2053 prepare_task_switch(rq, prev, next); 2054 2055 mm = next->mm; 2056 oldmm = prev->active_mm; 2057 /* 2058 * For paravirt, this is coupled with an exit in switch_to to 2059 * combine the page table reload and the switch backend into 2060 * one hypercall. 2061 */ 2062 arch_start_context_switch(prev); 2063 2064 if (!mm) { 2065 next->active_mm = oldmm; 2066 atomic_inc(&oldmm->mm_count); 2067 enter_lazy_tlb(oldmm, next); 2068 } else 2069 switch_mm(oldmm, mm, next); 2070 2071 if (!prev->mm) { 2072 prev->active_mm = NULL; 2073 rq->prev_mm = oldmm; 2074 } 2075 /* 2076 * Since the runqueue lock will be released by the next 2077 * task (which is an invalid locking op but in the case 2078 * of the scheduler it's an obvious special-case), so we 2079 * do an early lockdep release here: 2080 */ 2081#ifndef __ARCH_WANT_UNLOCKED_CTXSW 2082 spin_release(&rq->lock.dep_map, 1, _THIS_IP_); 2083#endif 2084 2085 /* Here we just switch the register state and the stack. */ 2086 switch_to(prev, next, prev); 2087 2088 barrier(); 2089 /* 2090 * this_rq must be evaluated again because prev may have moved 2091 * CPUs since it called schedule(), thus the 'rq' on its stack 2092 * frame will be invalid. 2093 */ 2094 finish_task_switch(this_rq(), prev); 2095} 2096 2097/* 2098 * nr_running, nr_uninterruptible and nr_context_switches: 2099 * 2100 * externally visible scheduler statistics: current number of runnable 2101 * threads, current number of uninterruptible-sleeping threads, total 2102 * number of context switches performed since bootup. 2103 */ 2104unsigned long nr_running(void) 2105{ 2106 unsigned long i, sum = 0; 2107 2108 for_each_online_cpu(i) 2109 sum += cpu_rq(i)->nr_running; 2110 2111 return sum; 2112} 2113 2114unsigned long nr_uninterruptible(void) 2115{ 2116 unsigned long i, sum = 0; 2117 2118 for_each_possible_cpu(i) 2119 sum += cpu_rq(i)->nr_uninterruptible; 2120 2121 /* 2122 * Since we read the counters lockless, it might be slightly 2123 * inaccurate. Do not allow it to go below zero though: 2124 */ 2125 if (unlikely((long)sum < 0)) 2126 sum = 0; 2127 2128 return sum; 2129} 2130 2131unsigned long long nr_context_switches(void) 2132{ 2133 int i; 2134 unsigned long long sum = 0; 2135 2136 for_each_possible_cpu(i) 2137 sum += cpu_rq(i)->nr_switches; 2138 2139 return sum; 2140} 2141 2142unsigned long nr_iowait(void) 2143{ 2144 unsigned long i, sum = 0; 2145 2146 for_each_possible_cpu(i) 2147 sum += atomic_read(&cpu_rq(i)->nr_iowait); 2148 2149 return sum; 2150} 2151 2152unsigned long nr_iowait_cpu(int cpu) 2153{ 2154 struct rq *this = cpu_rq(cpu); 2155 return atomic_read(&this->nr_iowait); 2156} 2157 2158unsigned long this_cpu_load(void) 2159{ 2160 struct rq *this = this_rq(); 2161 return this->cpu_load[0]; 2162} 2163 2164 2165/* Variables and functions for calc_load */ 2166static atomic_long_t calc_load_tasks; 2167static unsigned long calc_load_update; 2168unsigned long avenrun[3]; 2169EXPORT_SYMBOL(avenrun); 2170 2171static long calc_load_fold_active(struct rq *this_rq) 2172{ 2173 long nr_active, delta = 0; 2174 2175 nr_active = this_rq->nr_running; 2176 nr_active += (long) this_rq->nr_uninterruptible; 2177 2178 if (nr_active != this_rq->calc_load_active) { 2179 delta = nr_active - this_rq->calc_load_active; 2180 this_rq->calc_load_active = nr_active; 2181 } 2182 2183 return delta; 2184} 2185 2186static unsigned long 2187calc_load(unsigned long load, unsigned long exp, unsigned long active) 2188{ 2189 load *= exp; 2190 load += active * (FIXED_1 - exp); 2191 load += 1UL << (FSHIFT - 1); 2192 return load >> FSHIFT; 2193} 2194 2195#ifdef CONFIG_NO_HZ 2196/* 2197 * For NO_HZ we delay the active fold to the next LOAD_FREQ update. 2198 * 2199 * When making the ILB scale, we should try to pull this in as well. 2200 */ 2201static atomic_long_t calc_load_tasks_idle; 2202 2203void calc_load_account_idle(struct rq *this_rq) 2204{ 2205 long delta; 2206 2207 delta = calc_load_fold_active(this_rq); 2208 if (delta) 2209 atomic_long_add(delta, &calc_load_tasks_idle); 2210} 2211 2212static long calc_load_fold_idle(void) 2213{ 2214 long delta = 0; 2215 2216 /* 2217 * Its got a race, we don't care... 2218 */ 2219 if (atomic_long_read(&calc_load_tasks_idle)) 2220 delta = atomic_long_xchg(&calc_load_tasks_idle, 0); 2221 2222 return delta; 2223} 2224 2225/** 2226 * fixed_power_int - compute: x^n, in O(log n) time 2227 * 2228 * @x: base of the power 2229 * @frac_bits: fractional bits of @x 2230 * @n: power to raise @x to. 2231 * 2232 * By exploiting the relation between the definition of the natural power 2233 * function: x^n := x*x*...*x (x multiplied by itself for n times), and 2234 * the binary encoding of numbers used by computers: n := \Sum n_i * 2^i, 2235 * (where: n_i \elem {0, 1}, the binary vector representing n), 2236 * we find: x^n := x^(\Sum n_i * 2^i) := \Prod x^(n_i * 2^i), which is 2237 * of course trivially computable in O(log_2 n), the length of our binary 2238 * vector. 2239 */ 2240static unsigned long 2241fixed_power_int(unsigned long x, unsigned int frac_bits, unsigned int n) 2242{ 2243 unsigned long result = 1UL << frac_bits; 2244 2245 if (n) for (;;) { 2246 if (n & 1) { 2247 result *= x; 2248 result += 1UL << (frac_bits - 1); 2249 result >>= frac_bits; 2250 } 2251 n >>= 1; 2252 if (!n) 2253 break; 2254 x *= x; 2255 x += 1UL << (frac_bits - 1); 2256 x >>= frac_bits; 2257 } 2258 2259 return result; 2260} 2261 2262/* 2263 * a1 = a0 * e + a * (1 - e) 2264 * 2265 * a2 = a1 * e + a * (1 - e) 2266 * = (a0 * e + a * (1 - e)) * e + a * (1 - e) 2267 * = a0 * e^2 + a * (1 - e) * (1 + e) 2268 * 2269 * a3 = a2 * e + a * (1 - e) 2270 * = (a0 * e^2 + a * (1 - e) * (1 + e)) * e + a * (1 - e) 2271 * = a0 * e^3 + a * (1 - e) * (1 + e + e^2) 2272 * 2273 * ... 2274 * 2275 * an = a0 * e^n + a * (1 - e) * (1 + e + ... + e^n-1) [1] 2276 * = a0 * e^n + a * (1 - e) * (1 - e^n)/(1 - e) 2277 * = a0 * e^n + a * (1 - e^n) 2278 * 2279 * [1] application of the geometric series: 2280 * 2281 * n 1 - x^(n+1) 2282 * S_n := \Sum x^i = ------------- 2283 * i=0 1 - x 2284 */ 2285static unsigned long 2286calc_load_n(unsigned long load, unsigned long exp, 2287 unsigned long active, unsigned int n) 2288{ 2289 2290 return calc_load(load, fixed_power_int(exp, FSHIFT, n), active); 2291} 2292 2293/* 2294 * NO_HZ can leave us missing all per-cpu ticks calling 2295 * calc_load_account_active(), but since an idle CPU folds its delta into 2296 * calc_load_tasks_idle per calc_load_account_idle(), all we need to do is fold 2297 * in the pending idle delta if our idle period crossed a load cycle boundary. 2298 * 2299 * Once we've updated the global active value, we need to apply the exponential 2300 * weights adjusted to the number of cycles missed. 2301 */ 2302static void calc_global_nohz(void) 2303{ 2304 long delta, active, n; 2305 2306 /* 2307 * If we crossed a calc_load_update boundary, make sure to fold 2308 * any pending idle changes, the respective CPUs might have 2309 * missed the tick driven calc_load_account_active() update 2310 * due to NO_HZ. 2311 */ 2312 delta = calc_load_fold_idle(); 2313 if (delta) 2314 atomic_long_add(delta, &calc_load_tasks); 2315 2316 /* 2317 * It could be the one fold was all it took, we done! 2318 */ 2319 if (time_before(jiffies, calc_load_update + 10)) 2320 return; 2321 2322 /* 2323 * Catch-up, fold however many we are behind still 2324 */ 2325 delta = jiffies - calc_load_update - 10; 2326 n = 1 + (delta / LOAD_FREQ); 2327 2328 active = atomic_long_read(&calc_load_tasks); 2329 active = active > 0 ? active * FIXED_1 : 0; 2330 2331 avenrun[0] = calc_load_n(avenrun[0], EXP_1, active, n); 2332 avenrun[1] = calc_load_n(avenrun[1], EXP_5, active, n); 2333 avenrun[2] = calc_load_n(avenrun[2], EXP_15, active, n); 2334 2335 calc_load_update += n * LOAD_FREQ; 2336} 2337#else 2338void calc_load_account_idle(struct rq *this_rq) 2339{ 2340} 2341 2342static inline long calc_load_fold_idle(void) 2343{ 2344 return 0; 2345} 2346 2347static void calc_global_nohz(void) 2348{ 2349} 2350#endif 2351 2352/** 2353 * get_avenrun - get the load average array 2354 * @loads: pointer to dest load array 2355 * @offset: offset to add 2356 * @shift: shift count to shift the result left 2357 * 2358 * These values are estimates at best, so no need for locking. 2359 */ 2360void get_avenrun(unsigned long *loads, unsigned long offset, int shift) 2361{ 2362 loads[0] = (avenrun[0] + offset) << shift; 2363 loads[1] = (avenrun[1] + offset) << shift; 2364 loads[2] = (avenrun[2] + offset) << shift; 2365} 2366 2367/* 2368 * calc_load - update the avenrun load estimates 10 ticks after the 2369 * CPUs have updated calc_load_tasks. 2370 */ 2371void calc_global_load(unsigned long ticks) 2372{ 2373 long active; 2374 2375 if (time_before(jiffies, calc_load_update + 10)) 2376 return; 2377 2378 active = atomic_long_read(&calc_load_tasks); 2379 active = active > 0 ? active * FIXED_1 : 0; 2380 2381 avenrun[0] = calc_load(avenrun[0], EXP_1, active); 2382 avenrun[1] = calc_load(avenrun[1], EXP_5, active); 2383 avenrun[2] = calc_load(avenrun[2], EXP_15, active); 2384 2385 calc_load_update += LOAD_FREQ; 2386 2387 /* 2388 * Account one period with whatever state we found before 2389 * folding in the nohz state and ageing the entire idle period. 2390 * 2391 * This avoids loosing a sample when we go idle between 2392 * calc_load_account_active() (10 ticks ago) and now and thus 2393 * under-accounting. 2394 */ 2395 calc_global_nohz(); 2396} 2397 2398/* 2399 * Called from update_cpu_load() to periodically update this CPU's 2400 * active count. 2401 */ 2402static void calc_load_account_active(struct rq *this_rq) 2403{ 2404 long delta; 2405 2406 if (time_before(jiffies, this_rq->calc_load_update)) 2407 return; 2408 2409 delta = calc_load_fold_active(this_rq); 2410 delta += calc_load_fold_idle(); 2411 if (delta) 2412 atomic_long_add(delta, &calc_load_tasks); 2413 2414 this_rq->calc_load_update += LOAD_FREQ; 2415} 2416 2417/* 2418 * The exact cpuload at various idx values, calculated at every tick would be 2419 * load = (2^idx - 1) / 2^idx * load + 1 / 2^idx * cur_load 2420 * 2421 * If a cpu misses updates for n-1 ticks (as it was idle) and update gets called 2422 * on nth tick when cpu may be busy, then we have: 2423 * load = ((2^idx - 1) / 2^idx)^(n-1) * load 2424 * load = (2^idx - 1) / 2^idx) * load + 1 / 2^idx * cur_load 2425 * 2426 * decay_load_missed() below does efficient calculation of 2427 * load = ((2^idx - 1) / 2^idx)^(n-1) * load 2428 * avoiding 0..n-1 loop doing load = ((2^idx - 1) / 2^idx) * load 2429 * 2430 * The calculation is approximated on a 128 point scale. 2431 * degrade_zero_ticks is the number of ticks after which load at any 2432 * particular idx is approximated to be zero. 2433 * degrade_factor is a precomputed table, a row for each load idx. 2434 * Each column corresponds to degradation factor for a power of two ticks, 2435 * based on 128 point scale. 2436 * Example: 2437 * row 2, col 3 (=12) says that the degradation at load idx 2 after 2438 * 8 ticks is 12/128 (which is an approximation of exact factor 3^8/4^8). 2439 * 2440 * With this power of 2 load factors, we can degrade the load n times 2441 * by looking at 1 bits in n and doing as many mult/shift instead of 2442 * n mult/shifts needed by the exact degradation. 2443 */ 2444#define DEGRADE_SHIFT 7 2445static const unsigned char 2446 degrade_zero_ticks[CPU_LOAD_IDX_MAX] = {0, 8, 32, 64, 128}; 2447static const unsigned char 2448 degrade_factor[CPU_LOAD_IDX_MAX][DEGRADE_SHIFT + 1] = { 2449 {0, 0, 0, 0, 0, 0, 0, 0}, 2450 {64, 32, 8, 0, 0, 0, 0, 0}, 2451 {96, 72, 40, 12, 1, 0, 0}, 2452 {112, 98, 75, 43, 15, 1, 0}, 2453 {120, 112, 98, 76, 45, 16, 2} }; 2454 2455/* 2456 * Update cpu_load for any missed ticks, due to tickless idle. The backlog 2457 * would be when CPU is idle and so we just decay the old load without 2458 * adding any new load. 2459 */ 2460static unsigned long 2461decay_load_missed(unsigned long load, unsigned long missed_updates, int idx) 2462{ 2463 int j = 0; 2464 2465 if (!missed_updates) 2466 return load; 2467 2468 if (missed_updates >= degrade_zero_ticks[idx]) 2469 return 0; 2470 2471 if (idx == 1) 2472 return load >> missed_updates; 2473 2474 while (missed_updates) { 2475 if (missed_updates % 2) 2476 load = (load * degrade_factor[idx][j]) >> DEGRADE_SHIFT; 2477 2478 missed_updates >>= 1; 2479 j++; 2480 } 2481 return load; 2482} 2483 2484/* 2485 * Update rq->cpu_load[] statistics. This function is usually called every 2486 * scheduler tick (TICK_NSEC). With tickless idle this will not be called 2487 * every tick. We fix it up based on jiffies. 2488 */ 2489void update_cpu_load(struct rq *this_rq) 2490{ 2491 unsigned long this_load = this_rq->load.weight; 2492 unsigned long curr_jiffies = jiffies; 2493 unsigned long pending_updates; 2494 int i, scale; 2495 2496 this_rq->nr_load_updates++; 2497 2498 /* Avoid repeated calls on same jiffy, when moving in and out of idle */ 2499 if (curr_jiffies == this_rq->last_load_update_tick) 2500 return; 2501 2502 pending_updates = curr_jiffies - this_rq->last_load_update_tick; 2503 this_rq->last_load_update_tick = curr_jiffies; 2504 2505 /* Update our load: */ 2506 this_rq->cpu_load[0] = this_load; /* Fasttrack for idx 0 */ 2507 for (i = 1, scale = 2; i < CPU_LOAD_IDX_MAX; i++, scale += scale) { 2508 unsigned long old_load, new_load; 2509 2510 /* scale is effectively 1 << i now, and >> i divides by scale */ 2511 2512 old_load = this_rq->cpu_load[i]; 2513 old_load = decay_load_missed(old_load, pending_updates - 1, i); 2514 new_load = this_load; 2515 /* 2516 * Round up the averaging division if load is increasing. This 2517 * prevents us from getting stuck on 9 if the load is 10, for 2518 * example. 2519 */ 2520 if (new_load > old_load) 2521 new_load += scale - 1; 2522 2523 this_rq->cpu_load[i] = (old_load * (scale - 1) + new_load) >> i; 2524 } 2525 2526 sched_avg_update(this_rq); 2527} 2528 2529static void update_cpu_load_active(struct rq *this_rq) 2530{ 2531 update_cpu_load(this_rq); 2532 2533 calc_load_account_active(this_rq); 2534} 2535 2536#ifdef CONFIG_SMP 2537 2538/* 2539 * sched_exec - execve() is a valuable balancing opportunity, because at 2540 * this point the task has the smallest effective memory and cache footprint. 2541 */ 2542void sched_exec(void) 2543{ 2544 struct task_struct *p = current; 2545 unsigned long flags; 2546 int dest_cpu; 2547 2548 raw_spin_lock_irqsave(&p->pi_lock, flags); 2549 dest_cpu = p->sched_class->select_task_rq(p, SD_BALANCE_EXEC, 0); 2550 if (dest_cpu == smp_processor_id()) 2551 goto unlock; 2552 2553 if (likely(cpu_active(dest_cpu))) { 2554 struct migration_arg arg = { p, dest_cpu }; 2555 2556 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 2557 stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg); 2558 return; 2559 } 2560unlock: 2561 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 2562} 2563 2564#endif 2565 2566DEFINE_PER_CPU(struct kernel_stat, kstat); 2567DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat); 2568 2569EXPORT_PER_CPU_SYMBOL(kstat); 2570EXPORT_PER_CPU_SYMBOL(kernel_cpustat); 2571 2572/* 2573 * Return any ns on the sched_clock that have not yet been accounted in 2574 * @p in case that task is currently running. 2575 * 2576 * Called with task_rq_lock() held on @rq. 2577 */ 2578static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq) 2579{ 2580 u64 ns = 0; 2581 2582 if (task_current(rq, p)) { 2583 update_rq_clock(rq); 2584 ns = rq->clock_task - p->se.exec_start; 2585 if ((s64)ns < 0) 2586 ns = 0; 2587 } 2588 2589 return ns; 2590} 2591 2592unsigned long long task_delta_exec(struct task_struct *p) 2593{ 2594 unsigned long flags; 2595 struct rq *rq; 2596 u64 ns = 0; 2597 2598 rq = task_rq_lock(p, &flags); 2599 ns = do_task_delta_exec(p, rq); 2600 task_rq_unlock(rq, p, &flags); 2601 2602 return ns; 2603} 2604 2605/* 2606 * Return accounted runtime for the task. 2607 * In case the task is currently running, return the runtime plus current's 2608 * pending runtime that have not been accounted yet. 2609 */ 2610unsigned long long task_sched_runtime(struct task_struct *p) 2611{ 2612 unsigned long flags; 2613 struct rq *rq; 2614 u64 ns = 0; 2615 2616 rq = task_rq_lock(p, &flags); 2617 ns = p->se.sum_exec_runtime + do_task_delta_exec(p, rq); 2618 task_rq_unlock(rq, p, &flags); 2619 2620 return ns; 2621} 2622 2623#ifdef CONFIG_CGROUP_CPUACCT 2624struct cgroup_subsys cpuacct_subsys; 2625struct cpuacct root_cpuacct; 2626#endif 2627 2628static inline void task_group_account_field(struct task_struct *p, int index, 2629 u64 tmp) 2630{ 2631#ifdef CONFIG_CGROUP_CPUACCT 2632 struct kernel_cpustat *kcpustat; 2633 struct cpuacct *ca; 2634#endif 2635 /* 2636 * Since all updates are sure to touch the root cgroup, we 2637 * get ourselves ahead and touch it first. If the root cgroup 2638 * is the only cgroup, then nothing else should be necessary. 2639 * 2640 */ 2641 __get_cpu_var(kernel_cpustat).cpustat[index] += tmp; 2642 2643#ifdef CONFIG_CGROUP_CPUACCT 2644 if (unlikely(!cpuacct_subsys.active)) 2645 return; 2646 2647 rcu_read_lock(); 2648 ca = task_ca(p); 2649 while (ca && (ca != &root_cpuacct)) { 2650 kcpustat = this_cpu_ptr(ca->cpustat); 2651 kcpustat->cpustat[index] += tmp; 2652 ca = parent_ca(ca); 2653 } 2654 rcu_read_unlock(); 2655#endif 2656} 2657 2658 2659/* 2660 * Account user cpu time to a process. 2661 * @p: the process that the cpu time gets accounted to 2662 * @cputime: the cpu time spent in user space since the last update 2663 * @cputime_scaled: cputime scaled by cpu frequency 2664 */ 2665void account_user_time(struct task_struct *p, cputime_t cputime, 2666 cputime_t cputime_scaled) 2667{ 2668 int index; 2669 2670 /* Add user time to process. */ 2671 p->utime += cputime; 2672 p->utimescaled += cputime_scaled; 2673 account_group_user_time(p, cputime); 2674 2675 index = (TASK_NICE(p) > 0) ? CPUTIME_NICE : CPUTIME_USER; 2676 2677 /* Add user time to cpustat. */ 2678 task_group_account_field(p, index, (__force u64) cputime); 2679 2680 /* Account for user time used */ 2681 acct_update_integrals(p); 2682} 2683 2684/* 2685 * Account guest cpu time to a process. 2686 * @p: the process that the cpu time gets accounted to 2687 * @cputime: the cpu time spent in virtual machine since the last update 2688 * @cputime_scaled: cputime scaled by cpu frequency 2689 */ 2690static void account_guest_time(struct task_struct *p, cputime_t cputime, 2691 cputime_t cputime_scaled) 2692{ 2693 u64 *cpustat = kcpustat_this_cpu->cpustat; 2694 2695 /* Add guest time to process. */ 2696 p->utime += cputime; 2697 p->utimescaled += cputime_scaled; 2698 account_group_user_time(p, cputime); 2699 p->gtime += cputime; 2700 2701 /* Add guest time to cpustat. */ 2702 if (TASK_NICE(p) > 0) { 2703 cpustat[CPUTIME_NICE] += (__force u64) cputime; 2704 cpustat[CPUTIME_GUEST_NICE] += (__force u64) cputime; 2705 } else { 2706 cpustat[CPUTIME_USER] += (__force u64) cputime; 2707 cpustat[CPUTIME_GUEST] += (__force u64) cputime; 2708 } 2709} 2710 2711/* 2712 * Account system cpu time to a process and desired cpustat field 2713 * @p: the process that the cpu time gets accounted to 2714 * @cputime: the cpu time spent in kernel space since the last update 2715 * @cputime_scaled: cputime scaled by cpu frequency 2716 * @target_cputime64: pointer to cpustat field that has to be updated 2717 */ 2718static inline 2719void __account_system_time(struct task_struct *p, cputime_t cputime, 2720 cputime_t cputime_scaled, int index) 2721{ 2722 /* Add system time to process. */ 2723 p->stime += cputime; 2724 p->stimescaled += cputime_scaled; 2725 account_group_system_time(p, cputime); 2726 2727 /* Add system time to cpustat. */ 2728 task_group_account_field(p, index, (__force u64) cputime); 2729 2730 /* Account for system time used */ 2731 acct_update_integrals(p); 2732} 2733 2734/* 2735 * Account system cpu time to a process. 2736 * @p: the process that the cpu time gets accounted to 2737 * @hardirq_offset: the offset to subtract from hardirq_count() 2738 * @cputime: the cpu time spent in kernel space since the last update 2739 * @cputime_scaled: cputime scaled by cpu frequency 2740 */ 2741void account_system_time(struct task_struct *p, int hardirq_offset, 2742 cputime_t cputime, cputime_t cputime_scaled) 2743{ 2744 int index; 2745 2746 if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) { 2747 account_guest_time(p, cputime, cputime_scaled); 2748 return; 2749 } 2750 2751 if (hardirq_count() - hardirq_offset) 2752 index = CPUTIME_IRQ; 2753 else if (in_serving_softirq()) 2754 index = CPUTIME_SOFTIRQ; 2755 else 2756 index = CPUTIME_SYSTEM; 2757 2758 __account_system_time(p, cputime, cputime_scaled, index); 2759} 2760 2761/* 2762 * Account for involuntary wait time. 2763 * @cputime: the cpu time spent in involuntary wait 2764 */ 2765void account_steal_time(cputime_t cputime) 2766{ 2767 u64 *cpustat = kcpustat_this_cpu->cpustat; 2768 2769 cpustat[CPUTIME_STEAL] += (__force u64) cputime; 2770} 2771 2772/* 2773 * Account for idle time. 2774 * @cputime: the cpu time spent in idle wait 2775 */ 2776void account_idle_time(cputime_t cputime) 2777{ 2778 u64 *cpustat = kcpustat_this_cpu->cpustat; 2779 struct rq *rq = this_rq(); 2780 2781 if (atomic_read(&rq->nr_iowait) > 0) 2782 cpustat[CPUTIME_IOWAIT] += (__force u64) cputime; 2783 else 2784 cpustat[CPUTIME_IDLE] += (__force u64) cputime; 2785} 2786 2787static __always_inline bool steal_account_process_tick(void) 2788{ 2789#ifdef CONFIG_PARAVIRT 2790 if (static_key_false(¶virt_steal_enabled)) { 2791 u64 steal, st = 0; 2792 2793 steal = paravirt_steal_clock(smp_processor_id()); 2794 steal -= this_rq()->prev_steal_time; 2795 2796 st = steal_ticks(steal); 2797 this_rq()->prev_steal_time += st * TICK_NSEC; 2798 2799 account_steal_time(st); 2800 return st; 2801 } 2802#endif 2803 return false; 2804} 2805 2806#ifndef CONFIG_VIRT_CPU_ACCOUNTING 2807 2808#ifdef CONFIG_IRQ_TIME_ACCOUNTING 2809/* 2810 * Account a tick to a process and cpustat 2811 * @p: the process that the cpu time gets accounted to 2812 * @user_tick: is the tick from userspace 2813 * @rq: the pointer to rq 2814 * 2815 * Tick demultiplexing follows the order 2816 * - pending hardirq update 2817 * - pending softirq update 2818 * - user_time 2819 * - idle_time 2820 * - system time 2821 * - check for guest_time 2822 * - else account as system_time 2823 * 2824 * Check for hardirq is done both for system and user time as there is 2825 * no timer going off while we are on hardirq and hence we may never get an 2826 * opportunity to update it solely in system time. 2827 * p->stime and friends are only updated on system time and not on irq 2828 * softirq as those do not count in task exec_runtime any more. 2829 */ 2830static void irqtime_account_process_tick(struct task_struct *p, int user_tick, 2831 struct rq *rq) 2832{ 2833 cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy); 2834 u64 *cpustat = kcpustat_this_cpu->cpustat; 2835 2836 if (steal_account_process_tick()) 2837 return; 2838 2839 if (irqtime_account_hi_update()) { 2840 cpustat[CPUTIME_IRQ] += (__force u64) cputime_one_jiffy; 2841 } else if (irqtime_account_si_update()) { 2842 cpustat[CPUTIME_SOFTIRQ] += (__force u64) cputime_one_jiffy; 2843 } else if (this_cpu_ksoftirqd() == p) { 2844 /* 2845 * ksoftirqd time do not get accounted in cpu_softirq_time. 2846 * So, we have to handle it separately here. 2847 * Also, p->stime needs to be updated for ksoftirqd. 2848 */ 2849 __account_system_time(p, cputime_one_jiffy, one_jiffy_scaled, 2850 CPUTIME_SOFTIRQ); 2851 } else if (user_tick) { 2852 account_user_time(p, cputime_one_jiffy, one_jiffy_scaled); 2853 } else if (p == rq->idle) { 2854 account_idle_time(cputime_one_jiffy); 2855 } else if (p->flags & PF_VCPU) { /* System time or guest time */ 2856 account_guest_time(p, cputime_one_jiffy, one_jiffy_scaled); 2857 } else { 2858 __account_system_time(p, cputime_one_jiffy, one_jiffy_scaled, 2859 CPUTIME_SYSTEM); 2860 } 2861} 2862 2863static void irqtime_account_idle_ticks(int ticks) 2864{ 2865 int i; 2866 struct rq *rq = this_rq(); 2867 2868 for (i = 0; i < ticks; i++) 2869 irqtime_account_process_tick(current, 0, rq); 2870} 2871#else /* CONFIG_IRQ_TIME_ACCOUNTING */ 2872static void irqtime_account_idle_ticks(int ticks) {} 2873static void irqtime_account_process_tick(struct task_struct *p, int user_tick, 2874 struct rq *rq) {} 2875#endif /* CONFIG_IRQ_TIME_ACCOUNTING */ 2876 2877/* 2878 * Account a single tick of cpu time. 2879 * @p: the process that the cpu time gets accounted to 2880 * @user_tick: indicates if the tick is a user or a system tick 2881 */ 2882void account_process_tick(struct task_struct *p, int user_tick) 2883{ 2884 cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy); 2885 struct rq *rq = this_rq(); 2886 2887 if (sched_clock_irqtime) { 2888 irqtime_account_process_tick(p, user_tick, rq); 2889 return; 2890 } 2891 2892 if (steal_account_process_tick()) 2893 return; 2894 2895 if (user_tick) 2896 account_user_time(p, cputime_one_jiffy, one_jiffy_scaled); 2897 else if ((p != rq->idle) || (irq_count() != HARDIRQ_OFFSET)) 2898 account_system_time(p, HARDIRQ_OFFSET, cputime_one_jiffy, 2899 one_jiffy_scaled); 2900 else 2901 account_idle_time(cputime_one_jiffy); 2902} 2903 2904/* 2905 * Account multiple ticks of steal time. 2906 * @p: the process from which the cpu time has been stolen 2907 * @ticks: number of stolen ticks 2908 */ 2909void account_steal_ticks(unsigned long ticks) 2910{ 2911 account_steal_time(jiffies_to_cputime(ticks)); 2912} 2913 2914/* 2915 * Account multiple ticks of idle time. 2916 * @ticks: number of stolen ticks 2917 */ 2918void account_idle_ticks(unsigned long ticks) 2919{ 2920 2921 if (sched_clock_irqtime) { 2922 irqtime_account_idle_ticks(ticks); 2923 return; 2924 } 2925 2926 account_idle_time(jiffies_to_cputime(ticks)); 2927} 2928 2929#endif 2930 2931/* 2932 * Use precise platform statistics if available: 2933 */ 2934#ifdef CONFIG_VIRT_CPU_ACCOUNTING 2935void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st) 2936{ 2937 *ut = p->utime; 2938 *st = p->stime; 2939} 2940 2941void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st) 2942{ 2943 struct task_cputime cputime; 2944 2945 thread_group_cputime(p, &cputime); 2946 2947 *ut = cputime.utime; 2948 *st = cputime.stime; 2949} 2950#else 2951 2952#ifndef nsecs_to_cputime 2953# define nsecs_to_cputime(__nsecs) nsecs_to_jiffies(__nsecs) 2954#endif 2955 2956void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st) 2957{ 2958 cputime_t rtime, utime = p->utime, total = utime + p->stime; 2959 2960 /* 2961 * Use CFS's precise accounting: 2962 */ 2963 rtime = nsecs_to_cputime(p->se.sum_exec_runtime); 2964 2965 if (total) { 2966 u64 temp = (__force u64) rtime; 2967 2968 temp *= (__force u64) utime; 2969 do_div(temp, (__force u32) total); 2970 utime = (__force cputime_t) temp; 2971 } else 2972 utime = rtime; 2973 2974 /* 2975 * Compare with previous values, to keep monotonicity: 2976 */ 2977 p->prev_utime = max(p->prev_utime, utime); 2978 p->prev_stime = max(p->prev_stime, rtime - p->prev_utime); 2979 2980 *ut = p->prev_utime; 2981 *st = p->prev_stime; 2982} 2983 2984/* 2985 * Must be called with siglock held. 2986 */ 2987void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st) 2988{ 2989 struct signal_struct *sig = p->signal; 2990 struct task_cputime cputime; 2991 cputime_t rtime, utime, total; 2992 2993 thread_group_cputime(p, &cputime); 2994 2995 total = cputime.utime + cputime.stime; 2996 rtime = nsecs_to_cputime(cputime.sum_exec_runtime); 2997 2998 if (total) { 2999 u64 temp = (__force u64) rtime; 3000 3001 temp *= (__force u64) cputime.utime; 3002 do_div(temp, (__force u32) total); 3003 utime = (__force cputime_t) temp; 3004 } else 3005 utime = rtime; 3006 3007 sig->prev_utime = max(sig->prev_utime, utime); 3008 sig->prev_stime = max(sig->prev_stime, rtime - sig->prev_utime); 3009 3010 *ut = sig->prev_utime; 3011 *st = sig->prev_stime; 3012} 3013#endif 3014 3015/* 3016 * This function gets called by the timer code, with HZ frequency. 3017 * We call it with interrupts disabled. 3018 */ 3019void scheduler_tick(void) 3020{ 3021 int cpu = smp_processor_id(); 3022 struct rq *rq = cpu_rq(cpu); 3023 struct task_struct *curr = rq->curr; 3024 3025 sched_clock_tick(); 3026 3027 raw_spin_lock(&rq->lock); 3028 update_rq_clock(rq); 3029 update_cpu_load_active(rq); 3030 curr->sched_class->task_tick(rq, curr, 0); 3031 raw_spin_unlock(&rq->lock); 3032 3033 perf_event_task_tick(); 3034 3035#ifdef CONFIG_SMP 3036 rq->idle_balance = idle_cpu(cpu); 3037 trigger_load_balance(rq, cpu); 3038#endif 3039} 3040 3041notrace unsigned long get_parent_ip(unsigned long addr) 3042{ 3043 if (in_lock_functions(addr)) { 3044 addr = CALLER_ADDR2; 3045 if (in_lock_functions(addr)) 3046 addr = CALLER_ADDR3; 3047 } 3048 return addr; 3049} 3050 3051#if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \ 3052 defined(CONFIG_PREEMPT_TRACER)) 3053 3054void __kprobes add_preempt_count(int val) 3055{ 3056#ifdef CONFIG_DEBUG_PREEMPT 3057 /* 3058 * Underflow? 3059 */ 3060 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) 3061 return; 3062#endif 3063 preempt_count() += val; 3064#ifdef CONFIG_DEBUG_PREEMPT 3065 /* 3066 * Spinlock count overflowing soon? 3067 */ 3068 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= 3069 PREEMPT_MASK - 10); 3070#endif 3071 if (preempt_count() == val) 3072 trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); 3073} 3074EXPORT_SYMBOL(add_preempt_count); 3075 3076void __kprobes sub_preempt_count(int val) 3077{ 3078#ifdef CONFIG_DEBUG_PREEMPT 3079 /* 3080 * Underflow? 3081 */ 3082 if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) 3083 return; 3084 /* 3085 * Is the spinlock portion underflowing? 3086 */ 3087 if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && 3088 !(preempt_count() & PREEMPT_MASK))) 3089 return; 3090#endif 3091 3092 if (preempt_count() == val) 3093 trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); 3094 preempt_count() -= val; 3095} 3096EXPORT_SYMBOL(sub_preempt_count); 3097 3098#endif 3099 3100/* 3101 * Print scheduling while atomic bug: 3102 */ 3103static noinline void __schedule_bug(struct task_struct *prev) 3104{ 3105 if (oops_in_progress) 3106 return; 3107 3108 printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n", 3109 prev->comm, prev->pid, preempt_count()); 3110 3111 debug_show_held_locks(prev); 3112 print_modules(); 3113 if (irqs_disabled()) 3114 print_irqtrace_events(prev); 3115 dump_stack(); 3116} 3117 3118/* 3119 * Various schedule()-time debugging checks and statistics: 3120 */ 3121static inline void schedule_debug(struct task_struct *prev) 3122{ 3123 /* 3124 * Test if we are atomic. Since do_exit() needs to call into 3125 * schedule() atomically, we ignore that path for now. 3126 * Otherwise, whine if we are scheduling when we should not be. 3127 */ 3128 if (unlikely(in_atomic_preempt_off() && !prev->exit_state)) 3129 __schedule_bug(prev); 3130 rcu_sleep_check(); 3131 3132 profile_hit(SCHED_PROFILING, __builtin_return_address(0)); 3133 3134 schedstat_inc(this_rq(), sched_count); 3135} 3136 3137static void put_prev_task(struct rq *rq, struct task_struct *prev) 3138{ 3139 if (prev->on_rq || rq->skip_clock_update < 0) 3140 update_rq_clock(rq); 3141 prev->sched_class->put_prev_task(rq, prev); 3142} 3143 3144/* 3145 * Pick up the highest-prio task: 3146 */ 3147static inline struct task_struct * 3148pick_next_task(struct rq *rq) 3149{ 3150 const struct sched_class *class; 3151 struct task_struct *p; 3152 3153 /* 3154 * Optimization: we know that if all tasks are in 3155 * the fair class we can call that function directly: 3156 */ 3157 if (likely(rq->nr_running == rq->cfs.h_nr_running)) { 3158 p = fair_sched_class.pick_next_task(rq); 3159 if (likely(p)) 3160 return p; 3161 } 3162 3163 for_each_class(class) { 3164 p = class->pick_next_task(rq); 3165 if (p) 3166 return p; 3167 } 3168 3169 BUG(); /* the idle class will always have a runnable task */ 3170} 3171 3172/* 3173 * __schedule() is the main scheduler function. 3174 */ 3175static void __sched __schedule(void) 3176{ 3177 struct task_struct *prev, *next; 3178 unsigned long *switch_count; 3179 struct rq *rq; 3180 int cpu; 3181 3182need_resched: 3183 preempt_disable(); 3184 cpu = smp_processor_id(); 3185 rq = cpu_rq(cpu); 3186 rcu_note_context_switch(cpu); 3187 prev = rq->curr; 3188 3189 schedule_debug(prev); 3190 3191 if (sched_feat(HRTICK)) 3192 hrtick_clear(rq); 3193 3194 raw_spin_lock_irq(&rq->lock); 3195 3196 switch_count = &prev->nivcsw; 3197 if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { 3198 if (unlikely(signal_pending_state(prev->state, prev))) { 3199 prev->state = TASK_RUNNING; 3200 } else { 3201 deactivate_task(rq, prev, DEQUEUE_SLEEP); 3202 prev->on_rq = 0; 3203 3204 /* 3205 * If a worker went to sleep, notify and ask workqueue 3206 * whether it wants to wake up a task to maintain 3207 * concurrency. 3208 */ 3209 if (prev->flags & PF_WQ_WORKER) { 3210 struct task_struct *to_wakeup; 3211 3212 to_wakeup = wq_worker_sleeping(prev, cpu); 3213 if (to_wakeup) 3214 try_to_wake_up_local(to_wakeup); 3215 } 3216 } 3217 switch_count = &prev->nvcsw; 3218 } 3219 3220 pre_schedule(rq, prev); 3221 3222 if (unlikely(!rq->nr_running)) 3223 idle_balance(cpu, rq); 3224 3225 put_prev_task(rq, prev); 3226 next = pick_next_task(rq); 3227 clear_tsk_need_resched(prev); 3228 rq->skip_clock_update = 0; 3229 3230 if (likely(prev != next)) { 3231 rq->nr_switches++; 3232 rq->curr = next; 3233 ++*switch_count; 3234 3235 context_switch(rq, prev, next); /* unlocks the rq */ 3236 /* 3237 * The context switch have flipped the stack from under us 3238 * and restored the local variables which were saved when 3239 * this task called schedule() in the past. prev == current 3240 * is still correct, but it can be moved to another cpu/rq. 3241 */ 3242 cpu = smp_processor_id(); 3243 rq = cpu_rq(cpu); 3244 } else 3245 raw_spin_unlock_irq(&rq->lock); 3246 3247 post_schedule(rq); 3248 3249 sched_preempt_enable_no_resched(); 3250 if (need_resched()) 3251 goto need_resched; 3252} 3253 3254static inline void sched_submit_work(struct task_struct *tsk) 3255{ 3256 if (!tsk->state || tsk_is_pi_blocked(tsk)) 3257 return; 3258 /* 3259 * If we are going to sleep and we have plugged IO queued, 3260 * make sure to submit it to avoid deadlocks. 3261 */ 3262 if (blk_needs_flush_plug(tsk)) 3263 blk_schedule_flush_plug(tsk); 3264} 3265 3266asmlinkage void __sched schedule(void) 3267{ 3268 struct task_struct *tsk = current; 3269 3270 sched_submit_work(tsk); 3271 __schedule(); 3272} 3273EXPORT_SYMBOL(schedule); 3274 3275/** 3276 * schedule_preempt_disabled - called with preemption disabled 3277 * 3278 * Returns with preemption disabled. Note: preempt_count must be 1 3279 */ 3280void __sched schedule_preempt_disabled(void) 3281{ 3282 sched_preempt_enable_no_resched(); 3283 schedule(); 3284 preempt_disable(); 3285} 3286 3287#ifdef CONFIG_MUTEX_SPIN_ON_OWNER 3288 3289static inline bool owner_running(struct mutex *lock, struct task_struct *owner) 3290{ 3291 if (lock->owner != owner) 3292 return false; 3293 3294 /* 3295 * Ensure we emit the owner->on_cpu, dereference _after_ checking 3296 * lock->owner still matches owner, if that fails, owner might 3297 * point to free()d memory, if it still matches, the rcu_read_lock() 3298 * ensures the memory stays valid. 3299 */ 3300 barrier(); 3301 3302 return owner->on_cpu; 3303} 3304 3305/* 3306 * Look out! "owner" is an entirely speculative pointer 3307 * access and not reliable. 3308 */ 3309int mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner) 3310{ 3311 if (!sched_feat(OWNER_SPIN)) 3312 return 0; 3313 3314 rcu_read_lock(); 3315 while (owner_running(lock, owner)) { 3316 if (need_resched()) 3317 break; 3318 3319 arch_mutex_cpu_relax(); 3320 } 3321 rcu_read_unlock(); 3322 3323 /* 3324 * We break out the loop above on need_resched() and when the 3325 * owner changed, which is a sign for heavy contention. Return 3326 * success only when lock->owner is NULL. 3327 */ 3328 return lock->owner == NULL; 3329} 3330#endif 3331 3332#ifdef CONFIG_PREEMPT 3333/* 3334 * this is the entry point to schedule() from in-kernel preemption 3335 * off of preempt_enable. Kernel preemptions off return from interrupt 3336 * occur there and call schedule directly. 3337 */ 3338asmlinkage void __sched notrace preempt_schedule(void) 3339{ 3340 struct thread_info *ti = current_thread_info(); 3341 3342 /* 3343 * If there is a non-zero preempt_count or interrupts are disabled, 3344 * we do not want to preempt the current task. Just return.. 3345 */ 3346 if (likely(ti->preempt_count || irqs_disabled())) 3347 return; 3348 3349 do { 3350 add_preempt_count_notrace(PREEMPT_ACTIVE); 3351 __schedule(); 3352 sub_preempt_count_notrace(PREEMPT_ACTIVE); 3353 3354 /* 3355 * Check again in case we missed a preemption opportunity 3356 * between schedule and now. 3357 */ 3358 barrier(); 3359 } while (need_resched()); 3360} 3361EXPORT_SYMBOL(preempt_schedule); 3362 3363/* 3364 * this is the entry point to schedule() from kernel preemption 3365 * off of irq context. 3366 * Note, that this is called and return with irqs disabled. This will 3367 * protect us against recursive calling from irq. 3368 */ 3369asmlinkage void __sched preempt_schedule_irq(void) 3370{ 3371 struct thread_info *ti = current_thread_info(); 3372 3373 /* Catch callers which need to be fixed */ 3374 BUG_ON(ti->preempt_count || !irqs_disabled()); 3375 3376 do { 3377 add_preempt_count(PREEMPT_ACTIVE); 3378 local_irq_enable(); 3379 __schedule(); 3380 local_irq_disable(); 3381 sub_preempt_count(PREEMPT_ACTIVE); 3382 3383 /* 3384 * Check again in case we missed a preemption opportunity 3385 * between schedule and now. 3386 */ 3387 barrier(); 3388 } while (need_resched()); 3389} 3390 3391#endif /* CONFIG_PREEMPT */ 3392 3393int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags, 3394 void *key) 3395{ 3396 return try_to_wake_up(curr->private, mode, wake_flags); 3397} 3398EXPORT_SYMBOL(default_wake_function); 3399 3400/* 3401 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just 3402 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve 3403 * number) then we wake all the non-exclusive tasks and one exclusive task. 3404 * 3405 * There are circumstances in which we can try to wake a task which has already 3406 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns 3407 * zero in this (rare) case, and we handle it by continuing to scan the queue. 3408 */ 3409static void __wake_up_common(wait_queue_head_t *q, unsigned int mode, 3410 int nr_exclusive, int wake_flags, void *key) 3411{ 3412 wait_queue_t *curr, *next; 3413 3414 list_for_each_entry_safe(curr, next, &q->task_list, task_list) { 3415 unsigned flags = curr->flags; 3416 3417 if (curr->func(curr, mode, wake_flags, key) && 3418 (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive) 3419 break; 3420 } 3421} 3422 3423/** 3424 * __wake_up - wake up threads blocked on a waitqueue. 3425 * @q: the waitqueue 3426 * @mode: which threads 3427 * @nr_exclusive: how many wake-one or wake-many threads to wake up 3428 * @key: is directly passed to the wakeup function 3429 * 3430 * It may be assumed that this function implies a write memory barrier before 3431 * changing the task state if and only if any tasks are woken up. 3432 */ 3433void __wake_up(wait_queue_head_t *q, unsigned int mode, 3434 int nr_exclusive, void *key) 3435{ 3436 unsigned long flags; 3437 3438 spin_lock_irqsave(&q->lock, flags); 3439 __wake_up_common(q, mode, nr_exclusive, 0, key); 3440 spin_unlock_irqrestore(&q->lock, flags); 3441} 3442EXPORT_SYMBOL(__wake_up); 3443 3444/* 3445 * Same as __wake_up but called with the spinlock in wait_queue_head_t held. 3446 */ 3447void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr) 3448{ 3449 __wake_up_common(q, mode, nr, 0, NULL); 3450} 3451EXPORT_SYMBOL_GPL(__wake_up_locked); 3452 3453void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key) 3454{ 3455 __wake_up_common(q, mode, 1, 0, key); 3456} 3457EXPORT_SYMBOL_GPL(__wake_up_locked_key); 3458 3459/** 3460 * __wake_up_sync_key - wake up threads blocked on a waitqueue. 3461 * @q: the waitqueue 3462 * @mode: which threads 3463 * @nr_exclusive: how many wake-one or wake-many threads to wake up 3464 * @key: opaque value to be passed to wakeup targets 3465 * 3466 * The sync wakeup differs that the waker knows that it will schedule 3467 * away soon, so while the target thread will be woken up, it will not 3468 * be migrated to another CPU - ie. the two threads are 'synchronized' 3469 * with each other. This can prevent needless bouncing between CPUs. 3470 * 3471 * On UP it can prevent extra preemption. 3472 * 3473 * It may be assumed that this function implies a write memory barrier before 3474 * changing the task state if and only if any tasks are woken up. 3475 */ 3476void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, 3477 int nr_exclusive, void *key) 3478{ 3479 unsigned long flags; 3480 int wake_flags = WF_SYNC; 3481 3482 if (unlikely(!q)) 3483 return; 3484 3485 if (unlikely(!nr_exclusive)) 3486 wake_flags = 0; 3487 3488 spin_lock_irqsave(&q->lock, flags); 3489 __wake_up_common(q, mode, nr_exclusive, wake_flags, key); 3490 spin_unlock_irqrestore(&q->lock, flags); 3491} 3492EXPORT_SYMBOL_GPL(__wake_up_sync_key); 3493 3494/* 3495 * __wake_up_sync - see __wake_up_sync_key() 3496 */ 3497void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive) 3498{ 3499 __wake_up_sync_key(q, mode, nr_exclusive, NULL); 3500} 3501EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */ 3502 3503/** 3504 * complete: - signals a single thread waiting on this completion 3505 * @x: holds the state of this particular completion 3506 * 3507 * This will wake up a single thread waiting on this completion. Threads will be 3508 * awakened in the same order in which they were queued. 3509 * 3510 * See also complete_all(), wait_for_completion() and related routines. 3511 * 3512 * It may be assumed that this function implies a write memory barrier before 3513 * changing the task state if and only if any tasks are woken up. 3514 */ 3515void complete(struct completion *x) 3516{ 3517 unsigned long flags; 3518 3519 spin_lock_irqsave(&x->wait.lock, flags); 3520 x->done++; 3521 __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL); 3522 spin_unlock_irqrestore(&x->wait.lock, flags); 3523} 3524EXPORT_SYMBOL(complete); 3525 3526/** 3527 * complete_all: - signals all threads waiting on this completion 3528 * @x: holds the state of this particular completion 3529 * 3530 * This will wake up all threads waiting on this particular completion event. 3531 * 3532 * It may be assumed that this function implies a write memory barrier before 3533 * changing the task state if and only if any tasks are woken up. 3534 */ 3535void complete_all(struct completion *x) 3536{ 3537 unsigned long flags; 3538 3539 spin_lock_irqsave(&x->wait.lock, flags); 3540 x->done += UINT_MAX/2; 3541 __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL); 3542 spin_unlock_irqrestore(&x->wait.lock, flags); 3543} 3544EXPORT_SYMBOL(complete_all); 3545 3546static inline long __sched 3547do_wait_for_common(struct completion *x, long timeout, int state) 3548{ 3549 if (!x->done) { 3550 DECLARE_WAITQUEUE(wait, current); 3551 3552 __add_wait_queue_tail_exclusive(&x->wait, &wait); 3553 do { 3554 if (signal_pending_state(state, current)) { 3555 timeout = -ERESTARTSYS; 3556 break; 3557 } 3558 __set_current_state(state); 3559 spin_unlock_irq(&x->wait.lock); 3560 timeout = schedule_timeout(timeout); 3561 spin_lock_irq(&x->wait.lock); 3562 } while (!x->done && timeout); 3563 __remove_wait_queue(&x->wait, &wait); 3564 if (!x->done) 3565 return timeout; 3566 } 3567 x->done--; 3568 return timeout ?: 1; 3569} 3570 3571static long __sched 3572wait_for_common(struct completion *x, long timeout, int state) 3573{ 3574 might_sleep(); 3575 3576 spin_lock_irq(&x->wait.lock); 3577 timeout = do_wait_for_common(x, timeout, state); 3578 spin_unlock_irq(&x->wait.lock); 3579 return timeout; 3580} 3581 3582/** 3583 * wait_for_completion: - waits for completion of a task 3584 * @x: holds the state of this particular completion 3585 * 3586 * This waits to be signaled for completion of a specific task. It is NOT 3587 * interruptible and there is no timeout. 3588 * 3589 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout 3590 * and interrupt capability. Also see complete(). 3591 */ 3592void __sched wait_for_completion(struct completion *x) 3593{ 3594 wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE); 3595} 3596EXPORT_SYMBOL(wait_for_completion); 3597 3598/** 3599 * wait_for_completion_timeout: - waits for completion of a task (w/timeout) 3600 * @x: holds the state of this particular completion 3601 * @timeout: timeout value in jiffies 3602 * 3603 * This waits for either a completion of a specific task to be signaled or for a 3604 * specified timeout to expire. The timeout is in jiffies. It is not 3605 * interruptible. 3606 * 3607 * The return value is 0 if timed out, and positive (at least 1, or number of 3608 * jiffies left till timeout) if completed. 3609 */ 3610unsigned long __sched 3611wait_for_completion_timeout(struct completion *x, unsigned long timeout) 3612{ 3613 return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE); 3614} 3615EXPORT_SYMBOL(wait_for_completion_timeout); 3616 3617/** 3618 * wait_for_completion_interruptible: - waits for completion of a task (w/intr) 3619 * @x: holds the state of this particular completion 3620 * 3621 * This waits for completion of a specific task to be signaled. It is 3622 * interruptible. 3623 * 3624 * The return value is -ERESTARTSYS if interrupted, 0 if completed. 3625 */ 3626int __sched wait_for_completion_interruptible(struct completion *x) 3627{ 3628 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE); 3629 if (t == -ERESTARTSYS) 3630 return t; 3631 return 0; 3632} 3633EXPORT_SYMBOL(wait_for_completion_interruptible); 3634 3635/** 3636 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr)) 3637 * @x: holds the state of this particular completion 3638 * @timeout: timeout value in jiffies 3639 * 3640 * This waits for either a completion of a specific task to be signaled or for a 3641 * specified timeout to expire. It is interruptible. The timeout is in jiffies. 3642 * 3643 * The return value is -ERESTARTSYS if interrupted, 0 if timed out, 3644 * positive (at least 1, or number of jiffies left till timeout) if completed. 3645 */ 3646long __sched 3647wait_for_completion_interruptible_timeout(struct completion *x, 3648 unsigned long timeout) 3649{ 3650 return wait_for_common(x, timeout, TASK_INTERRUPTIBLE); 3651} 3652EXPORT_SYMBOL(wait_for_completion_interruptible_timeout); 3653 3654/** 3655 * wait_for_completion_killable: - waits for completion of a task (killable) 3656 * @x: holds the state of this particular completion 3657 * 3658 * This waits to be signaled for completion of a specific task. It can be 3659 * interrupted by a kill signal. 3660 * 3661 * The return value is -ERESTARTSYS if interrupted, 0 if completed. 3662 */ 3663int __sched wait_for_completion_killable(struct completion *x) 3664{ 3665 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE); 3666 if (t == -ERESTARTSYS) 3667 return t; 3668 return 0; 3669} 3670EXPORT_SYMBOL(wait_for_completion_killable); 3671 3672/** 3673 * wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable)) 3674 * @x: holds the state of this particular completion 3675 * @timeout: timeout value in jiffies 3676 * 3677 * This waits for either a completion of a specific task to be 3678 * signaled or for a specified timeout to expire. It can be 3679 * interrupted by a kill signal. The timeout is in jiffies. 3680 * 3681 * The return value is -ERESTARTSYS if interrupted, 0 if timed out, 3682 * positive (at least 1, or number of jiffies left till timeout) if completed. 3683 */ 3684long __sched 3685wait_for_completion_killable_timeout(struct completion *x, 3686 unsigned long timeout) 3687{ 3688 return wait_for_common(x, timeout, TASK_KILLABLE); 3689} 3690EXPORT_SYMBOL(wait_for_completion_killable_timeout); 3691 3692/** 3693 * try_wait_for_completion - try to decrement a completion without blocking 3694 * @x: completion structure 3695 * 3696 * Returns: 0 if a decrement cannot be done without blocking 3697 * 1 if a decrement succeeded. 3698 * 3699 * If a completion is being used as a counting completion, 3700 * attempt to decrement the counter without blocking. This 3701 * enables us to avoid waiting if the resource the completion 3702 * is protecting is not available. 3703 */ 3704bool try_wait_for_completion(struct completion *x) 3705{ 3706 unsigned long flags; 3707 int ret = 1; 3708 3709 spin_lock_irqsave(&x->wait.lock, flags); 3710 if (!x->done) 3711 ret = 0; 3712 else 3713 x->done--; 3714 spin_unlock_irqrestore(&x->wait.lock, flags); 3715 return ret; 3716} 3717EXPORT_SYMBOL(try_wait_for_completion); 3718 3719/** 3720 * completion_done - Test to see if a completion has any waiters 3721 * @x: completion structure 3722 * 3723 * Returns: 0 if there are waiters (wait_for_completion() in progress) 3724 * 1 if there are no waiters. 3725 * 3726 */ 3727bool completion_done(struct completion *x) 3728{ 3729 unsigned long flags; 3730 int ret = 1; 3731 3732 spin_lock_irqsave(&x->wait.lock, flags); 3733 if (!x->done) 3734 ret = 0; 3735 spin_unlock_irqrestore(&x->wait.lock, flags); 3736 return ret; 3737} 3738EXPORT_SYMBOL(completion_done); 3739 3740static long __sched 3741sleep_on_common(wait_queue_head_t *q, int state, long timeout) 3742{ 3743 unsigned long flags; 3744 wait_queue_t wait; 3745 3746 init_waitqueue_entry(&wait, current); 3747 3748 __set_current_state(state); 3749 3750 spin_lock_irqsave(&q->lock, flags); 3751 __add_wait_queue(q, &wait); 3752 spin_unlock(&q->lock); 3753 timeout = schedule_timeout(timeout); 3754 spin_lock_irq(&q->lock); 3755 __remove_wait_queue(q, &wait); 3756 spin_unlock_irqrestore(&q->lock, flags); 3757 3758 return timeout; 3759} 3760 3761void __sched interruptible_sleep_on(wait_queue_head_t *q) 3762{ 3763 sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); 3764} 3765EXPORT_SYMBOL(interruptible_sleep_on); 3766 3767long __sched 3768interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout) 3769{ 3770 return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout); 3771} 3772EXPORT_SYMBOL(interruptible_sleep_on_timeout); 3773 3774void __sched sleep_on(wait_queue_head_t *q) 3775{ 3776 sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); 3777} 3778EXPORT_SYMBOL(sleep_on); 3779 3780long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout) 3781{ 3782 return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout); 3783} 3784EXPORT_SYMBOL(sleep_on_timeout); 3785 3786#ifdef CONFIG_RT_MUTEXES 3787 3788/* 3789 * rt_mutex_setprio - set the current priority of a task 3790 * @p: task 3791 * @prio: prio value (kernel-internal form) 3792 * 3793 * This function changes the 'effective' priority of a task. It does 3794 * not touch ->normal_prio like __setscheduler(). 3795 * 3796 * Used by the rt_mutex code to implement priority inheritance logic. 3797 */ 3798void rt_mutex_setprio(struct task_struct *p, int prio) 3799{ 3800 int oldprio, on_rq, running; 3801 struct rq *rq; 3802 const struct sched_class *prev_class; 3803 3804 BUG_ON(prio < 0 || prio > MAX_PRIO); 3805 3806 rq = __task_rq_lock(p); 3807 3808 /* 3809 * Idle task boosting is a nono in general. There is one 3810 * exception, when PREEMPT_RT and NOHZ is active: 3811 * 3812 * The idle task calls get_next_timer_interrupt() and holds 3813 * the timer wheel base->lock on the CPU and another CPU wants 3814 * to access the timer (probably to cancel it). We can safely 3815 * ignore the boosting request, as the idle CPU runs this code 3816 * with interrupts disabled and will complete the lock 3817 * protected section without being interrupted. So there is no 3818 * real need to boost. 3819 */ 3820 if (unlikely(p == rq->idle)) { 3821 WARN_ON(p != rq->curr); 3822 WARN_ON(p->pi_blocked_on); 3823 goto out_unlock; 3824 } 3825 3826 trace_sched_pi_setprio(p, prio); 3827 oldprio = p->prio; 3828 prev_class = p->sched_class; 3829 on_rq = p->on_rq; 3830 running = task_current(rq, p); 3831 if (on_rq) 3832 dequeue_task(rq, p, 0); 3833 if (running) 3834 p->sched_class->put_prev_task(rq, p); 3835 3836 if (rt_prio(prio)) 3837 p->sched_class = &rt_sched_class; 3838 else 3839 p->sched_class = &fair_sched_class; 3840 3841 p->prio = prio; 3842 3843 if (running) 3844 p->sched_class->set_curr_task(rq); 3845 if (on_rq) 3846 enqueue_task(rq, p, oldprio < prio ? ENQUEUE_HEAD : 0); 3847 3848 check_class_changed(rq, p, prev_class, oldprio); 3849out_unlock: 3850 __task_rq_unlock(rq); 3851} 3852#endif 3853void set_user_nice(struct task_struct *p, long nice) 3854{ 3855 int old_prio, delta, on_rq; 3856 unsigned long flags; 3857 struct rq *rq; 3858 3859 if (TASK_NICE(p) == nice || nice < -20 || nice > 19) 3860 return; 3861 /* 3862 * We have to be careful, if called from sys_setpriority(), 3863 * the task might be in the middle of scheduling on another CPU. 3864 */ 3865 rq = task_rq_lock(p, &flags); 3866 /* 3867 * The RT priorities are set via sched_setscheduler(), but we still 3868 * allow the 'normal' nice value to be set - but as expected 3869 * it wont have any effect on scheduling until the task is 3870 * SCHED_FIFO/SCHED_RR: 3871 */ 3872 if (task_has_rt_policy(p)) { 3873 p->static_prio = NICE_TO_PRIO(nice); 3874 goto out_unlock; 3875 } 3876 on_rq = p->on_rq; 3877 if (on_rq) 3878 dequeue_task(rq, p, 0); 3879 3880 p->static_prio = NICE_TO_PRIO(nice); 3881 set_load_weight(p); 3882 old_prio = p->prio; 3883 p->prio = effective_prio(p); 3884 delta = p->prio - old_prio; 3885 3886 if (on_rq) { 3887 enqueue_task(rq, p, 0); 3888 /* 3889 * If the task increased its priority or is running and 3890 * lowered its priority, then reschedule its CPU: 3891 */ 3892 if (delta < 0 || (delta > 0 && task_running(rq, p))) 3893 resched_task(rq->curr); 3894 } 3895out_unlock: 3896 task_rq_unlock(rq, p, &flags); 3897} 3898EXPORT_SYMBOL(set_user_nice); 3899 3900/* 3901 * can_nice - check if a task can reduce its nice value 3902 * @p: task 3903 * @nice: nice value 3904 */ 3905int can_nice(const struct task_struct *p, const int nice) 3906{ 3907 /* convert nice value [19,-20] to rlimit style value [1,40] */ 3908 int nice_rlim = 20 - nice; 3909 3910 return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) || 3911 capable(CAP_SYS_NICE)); 3912} 3913 3914#ifdef __ARCH_WANT_SYS_NICE 3915 3916/* 3917 * sys_nice - change the priority of the current process. 3918 * @increment: priority increment 3919 * 3920 * sys_setpriority is a more generic, but much slower function that 3921 * does similar things. 3922 */ 3923SYSCALL_DEFINE1(nice, int, increment) 3924{ 3925 long nice, retval; 3926 3927 /* 3928 * Setpriority might change our priority at the same moment. 3929 * We don't have to worry. Conceptually one call occurs first 3930 * and we have a single winner. 3931 */ 3932 if (increment < -40) 3933 increment = -40; 3934 if (increment > 40) 3935 increment = 40; 3936 3937 nice = TASK_NICE(current) + increment; 3938 if (nice < -20) 3939 nice = -20; 3940 if (nice > 19) 3941 nice = 19; 3942 3943 if (increment < 0 && !can_nice(current, nice)) 3944 return -EPERM; 3945 3946 retval = security_task_setnice(current, nice); 3947 if (retval) 3948 return retval; 3949 3950 set_user_nice(current, nice); 3951 return 0; 3952} 3953 3954#endif 3955 3956/** 3957 * task_prio - return the priority value of a given task. 3958 * @p: the task in question. 3959 * 3960 * This is the priority value as seen by users in /proc. 3961 * RT tasks are offset by -200. Normal tasks are centered 3962 * around 0, value goes from -16 to +15. 3963 */ 3964int task_prio(const struct task_struct *p) 3965{ 3966 return p->prio - MAX_RT_PRIO; 3967} 3968 3969/** 3970 * task_nice - return the nice value of a given task. 3971 * @p: the task in question. 3972 */ 3973int task_nice(const struct task_struct *p) 3974{ 3975 return TASK_NICE(p); 3976} 3977EXPORT_SYMBOL(task_nice); 3978 3979/** 3980 * idle_cpu - is a given cpu idle currently? 3981 * @cpu: the processor in question. 3982 */ 3983int idle_cpu(int cpu) 3984{ 3985 struct rq *rq = cpu_rq(cpu); 3986 3987 if (rq->curr != rq->idle) 3988 return 0; 3989 3990 if (rq->nr_running) 3991 return 0; 3992 3993#ifdef CONFIG_SMP 3994 if (!llist_empty(&rq->wake_list)) 3995 return 0; 3996#endif 3997 3998 return 1; 3999} 4000 4001/** 4002 * idle_task - return the idle task for a given cpu. 4003 * @cpu: the processor in question. 4004 */ 4005struct task_struct *idle_task(int cpu) 4006{ 4007 return cpu_rq(cpu)->idle; 4008} 4009 4010/** 4011 * find_process_by_pid - find a process with a matching PID value. 4012 * @pid: the pid in question. 4013 */ 4014static struct task_struct *find_process_by_pid(pid_t pid) 4015{ 4016 return pid ? find_task_by_vpid(pid) : current; 4017} 4018 4019/* Actually do priority change: must hold rq lock. */ 4020static void 4021__setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio) 4022{ 4023 p->policy = policy; 4024 p->rt_priority = prio; 4025 p->normal_prio = normal_prio(p); 4026 /* we are holding p->pi_lock already */ 4027 p->prio = rt_mutex_getprio(p); 4028 if (rt_prio(p->prio)) 4029 p->sched_class = &rt_sched_class; 4030 else 4031 p->sched_class = &fair_sched_class; 4032 set_load_weight(p); 4033} 4034 4035/* 4036 * check the target process has a UID that matches the current process's 4037 */ 4038static bool check_same_owner(struct task_struct *p) 4039{ 4040 const struct cred *cred = current_cred(), *pcred; 4041 bool match; 4042 4043 rcu_read_lock(); 4044 pcred = __task_cred(p); 4045 match = (uid_eq(cred->euid, pcred->euid) || 4046 uid_eq(cred->euid, pcred->uid)); 4047 rcu_read_unlock(); 4048 return match; 4049} 4050 4051static int __sched_setscheduler(struct task_struct *p, int policy, 4052 const struct sched_param *param, bool user) 4053{ 4054 int retval, oldprio, oldpolicy = -1, on_rq, running; 4055 unsigned long flags; 4056 const struct sched_class *prev_class; 4057 struct rq *rq; 4058 int reset_on_fork; 4059 4060 /* may grab non-irq protected spin_locks */ 4061 BUG_ON(in_interrupt()); 4062recheck: 4063 /* double check policy once rq lock held */ 4064 if (policy < 0) { 4065 reset_on_fork = p->sched_reset_on_fork; 4066 policy = oldpolicy = p->policy; 4067 } else { 4068 reset_on_fork = !!(policy & SCHED_RESET_ON_FORK); 4069 policy &= ~SCHED_RESET_ON_FORK; 4070 4071 if (policy != SCHED_FIFO && policy != SCHED_RR && 4072 policy != SCHED_NORMAL && policy != SCHED_BATCH && 4073 policy != SCHED_IDLE) 4074 return -EINVAL; 4075 } 4076 4077 /* 4078 * Valid priorities for SCHED_FIFO and SCHED_RR are 4079 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL, 4080 * SCHED_BATCH and SCHED_IDLE is 0. 4081 */ 4082 if (param->sched_priority < 0 || 4083 (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) || 4084 (!p->mm && param->sched_priority > MAX_RT_PRIO-1)) 4085 return -EINVAL; 4086 if (rt_policy(policy) != (param->sched_priority != 0)) 4087 return -EINVAL; 4088 4089 /* 4090 * Allow unprivileged RT tasks to decrease priority: 4091 */ 4092 if (user && !capable(CAP_SYS_NICE)) { 4093 if (rt_policy(policy)) { 4094 unsigned long rlim_rtprio = 4095 task_rlimit(p, RLIMIT_RTPRIO); 4096 4097 /* can't set/change the rt policy */ 4098 if (policy != p->policy && !rlim_rtprio) 4099 return -EPERM; 4100 4101 /* can't increase priority */ 4102 if (param->sched_priority > p->rt_priority && 4103 param->sched_priority > rlim_rtprio) 4104 return -EPERM; 4105 } 4106 4107 /* 4108 * Treat SCHED_IDLE as nice 20. Only allow a switch to 4109 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it. 4110 */ 4111 if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) { 4112 if (!can_nice(p, TASK_NICE(p))) 4113 return -EPERM; 4114 } 4115 4116 /* can't change other user's priorities */ 4117 if (!check_same_owner(p)) 4118 return -EPERM; 4119 4120 /* Normal users shall not reset the sched_reset_on_fork flag */ 4121 if (p->sched_reset_on_fork && !reset_on_fork) 4122 return -EPERM; 4123 } 4124 4125 if (user) { 4126 retval = security_task_setscheduler(p); 4127 if (retval) 4128 return retval; 4129 } 4130 4131 /* 4132 * make sure no PI-waiters arrive (or leave) while we are 4133 * changing the priority of the task: 4134 * 4135 * To be able to change p->policy safely, the appropriate 4136 * runqueue lock must be held. 4137 */ 4138 rq = task_rq_lock(p, &flags); 4139 4140 /* 4141 * Changing the policy of the stop threads its a very bad idea 4142 */ 4143 if (p == rq->stop) { 4144 task_rq_unlock(rq, p, &flags); 4145 return -EINVAL; 4146 } 4147 4148 /* 4149 * If not changing anything there's no need to proceed further: 4150 */ 4151 if (unlikely(policy == p->policy && (!rt_policy(policy) || 4152 param->sched_priority == p->rt_priority))) { 4153 4154 __task_rq_unlock(rq); 4155 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 4156 return 0; 4157 } 4158 4159#ifdef CONFIG_RT_GROUP_SCHED 4160 if (user) { 4161 /* 4162 * Do not allow realtime tasks into groups that have no runtime 4163 * assigned. 4164 */ 4165 if (rt_bandwidth_enabled() && rt_policy(policy) && 4166 task_group(p)->rt_bandwidth.rt_runtime == 0 && 4167 !task_group_is_autogroup(task_group(p))) { 4168 task_rq_unlock(rq, p, &flags); 4169 return -EPERM; 4170 } 4171 } 4172#endif 4173 4174 /* recheck policy now with rq lock held */ 4175 if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { 4176 policy = oldpolicy = -1; 4177 task_rq_unlock(rq, p, &flags); 4178 goto recheck; 4179 } 4180 on_rq = p->on_rq; 4181 running = task_current(rq, p); 4182 if (on_rq) 4183 dequeue_task(rq, p, 0); 4184 if (running) 4185 p->sched_class->put_prev_task(rq, p); 4186 4187 p->sched_reset_on_fork = reset_on_fork; 4188 4189 oldprio = p->prio; 4190 prev_class = p->sched_class; 4191 __setscheduler(rq, p, policy, param->sched_priority); 4192 4193 if (running) 4194 p->sched_class->set_curr_task(rq); 4195 if (on_rq) 4196 enqueue_task(rq, p, 0); 4197 4198 check_class_changed(rq, p, prev_class, oldprio); 4199 task_rq_unlock(rq, p, &flags); 4200 4201 rt_mutex_adjust_pi(p); 4202 4203 return 0; 4204} 4205 4206/** 4207 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. 4208 * @p: the task in question. 4209 * @policy: new policy. 4210 * @param: structure containing the new RT priority. 4211 * 4212 * NOTE that the task may be already dead. 4213 */ 4214int sched_setscheduler(struct task_struct *p, int policy, 4215 const struct sched_param *param) 4216{ 4217 return __sched_setscheduler(p, policy, param, true); 4218} 4219EXPORT_SYMBOL_GPL(sched_setscheduler); 4220 4221/** 4222 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace. 4223 * @p: the task in question. 4224 * @policy: new policy. 4225 * @param: structure containing the new RT priority. 4226 * 4227 * Just like sched_setscheduler, only don't bother checking if the 4228 * current context has permission. For example, this is needed in 4229 * stop_machine(): we create temporary high priority worker threads, 4230 * but our caller might not have that capability. 4231 */ 4232int sched_setscheduler_nocheck(struct task_struct *p, int policy, 4233 const struct sched_param *param) 4234{ 4235 return __sched_setscheduler(p, policy, param, false); 4236} 4237 4238static int 4239do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) 4240{ 4241 struct sched_param lparam; 4242 struct task_struct *p; 4243 int retval; 4244 4245 if (!param || pid < 0) 4246 return -EINVAL; 4247 if (copy_from_user(&lparam, param, sizeof(struct sched_param))) 4248 return -EFAULT; 4249 4250 rcu_read_lock(); 4251 retval = -ESRCH; 4252 p = find_process_by_pid(pid); 4253 if (p != NULL) 4254 retval = sched_setscheduler(p, policy, &lparam); 4255 rcu_read_unlock(); 4256 4257 return retval; 4258} 4259 4260/** 4261 * sys_sched_setscheduler - set/change the scheduler policy and RT priority 4262 * @pid: the pid in question. 4263 * @policy: new policy. 4264 * @param: structure containing the new RT priority. 4265 */ 4266SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy, 4267 struct sched_param __user *, param) 4268{ 4269 /* negative values for policy are not valid */ 4270 if (policy < 0) 4271 return -EINVAL; 4272 4273 return do_sched_setscheduler(pid, policy, param); 4274} 4275 4276/** 4277 * sys_sched_setparam - set/change the RT priority of a thread 4278 * @pid: the pid in question. 4279 * @param: structure containing the new RT priority. 4280 */ 4281SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param) 4282{ 4283 return do_sched_setscheduler(pid, -1, param); 4284} 4285 4286/** 4287 * sys_sched_getscheduler - get the policy (scheduling class) of a thread 4288 * @pid: the pid in question. 4289 */ 4290SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid) 4291{ 4292 struct task_struct *p; 4293 int retval; 4294 4295 if (pid < 0) 4296 return -EINVAL; 4297 4298 retval = -ESRCH; 4299 rcu_read_lock(); 4300 p = find_process_by_pid(pid); 4301 if (p) { 4302 retval = security_task_getscheduler(p); 4303 if (!retval) 4304 retval = p->policy 4305 | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0); 4306 } 4307 rcu_read_unlock(); 4308 return retval; 4309} 4310 4311/** 4312 * sys_sched_getparam - get the RT priority of a thread 4313 * @pid: the pid in question. 4314 * @param: structure containing the RT priority. 4315 */ 4316SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param) 4317{ 4318 struct sched_param lp; 4319 struct task_struct *p; 4320 int retval; 4321 4322 if (!param || pid < 0) 4323 return -EINVAL; 4324 4325 rcu_read_lock(); 4326 p = find_process_by_pid(pid); 4327 retval = -ESRCH; 4328 if (!p) 4329 goto out_unlock; 4330 4331 retval = security_task_getscheduler(p); 4332 if (retval) 4333 goto out_unlock; 4334 4335 lp.sched_priority = p->rt_priority; 4336 rcu_read_unlock(); 4337 4338 /* 4339 * This one might sleep, we cannot do it with a spinlock held ... 4340 */ 4341 retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; 4342 4343 return retval; 4344 4345out_unlock: 4346 rcu_read_unlock(); 4347 return retval; 4348} 4349 4350long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) 4351{ 4352 cpumask_var_t cpus_allowed, new_mask; 4353 struct task_struct *p; 4354 int retval; 4355 4356 get_online_cpus(); 4357 rcu_read_lock(); 4358 4359 p = find_process_by_pid(pid); 4360 if (!p) { 4361 rcu_read_unlock(); 4362 put_online_cpus(); 4363 return -ESRCH; 4364 } 4365 4366 /* Prevent p going away */ 4367 get_task_struct(p); 4368 rcu_read_unlock(); 4369 4370 if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) { 4371 retval = -ENOMEM; 4372 goto out_put_task; 4373 } 4374 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) { 4375 retval = -ENOMEM; 4376 goto out_free_cpus_allowed; 4377 } 4378 retval = -EPERM; 4379 if (!check_same_owner(p) && !ns_capable(task_user_ns(p), CAP_SYS_NICE)) 4380 goto out_unlock; 4381 4382 retval = security_task_setscheduler(p); 4383 if (retval) 4384 goto out_unlock; 4385 4386 cpuset_cpus_allowed(p, cpus_allowed); 4387 cpumask_and(new_mask, in_mask, cpus_allowed); 4388again: 4389 retval = set_cpus_allowed_ptr(p, new_mask); 4390 4391 if (!retval) { 4392 cpuset_cpus_allowed(p, cpus_allowed); 4393 if (!cpumask_subset(new_mask, cpus_allowed)) { 4394 /* 4395 * We must have raced with a concurrent cpuset 4396 * update. Just reset the cpus_allowed to the 4397 * cpuset's cpus_allowed 4398 */ 4399 cpumask_copy(new_mask, cpus_allowed); 4400 goto again; 4401 } 4402 } 4403out_unlock: 4404 free_cpumask_var(new_mask); 4405out_free_cpus_allowed: 4406 free_cpumask_var(cpus_allowed); 4407out_put_task: 4408 put_task_struct(p); 4409 put_online_cpus(); 4410 return retval; 4411} 4412 4413static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, 4414 struct cpumask *new_mask) 4415{ 4416 if (len < cpumask_size()) 4417 cpumask_clear(new_mask); 4418 else if (len > cpumask_size()) 4419 len = cpumask_size(); 4420 4421 return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; 4422} 4423 4424/** 4425 * sys_sched_setaffinity - set the cpu affinity of a process 4426 * @pid: pid of the process 4427 * @len: length in bytes of the bitmask pointed to by user_mask_ptr 4428 * @user_mask_ptr: user-space pointer to the new cpu mask 4429 */ 4430SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len, 4431 unsigned long __user *, user_mask_ptr) 4432{ 4433 cpumask_var_t new_mask; 4434 int retval; 4435 4436 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) 4437 return -ENOMEM; 4438 4439 retval = get_user_cpu_mask(user_mask_ptr, len, new_mask); 4440 if (retval == 0) 4441 retval = sched_setaffinity(pid, new_mask); 4442 free_cpumask_var(new_mask); 4443 return retval; 4444} 4445 4446long sched_getaffinity(pid_t pid, struct cpumask *mask) 4447{ 4448 struct task_struct *p; 4449 unsigned long flags; 4450 int retval; 4451 4452 get_online_cpus(); 4453 rcu_read_lock(); 4454 4455 retval = -ESRCH; 4456 p = find_process_by_pid(pid); 4457 if (!p) 4458 goto out_unlock; 4459 4460 retval = security_task_getscheduler(p); 4461 if (retval) 4462 goto out_unlock; 4463 4464 raw_spin_lock_irqsave(&p->pi_lock, flags); 4465 cpumask_and(mask, &p->cpus_allowed, cpu_online_mask); 4466 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 4467 4468out_unlock: 4469 rcu_read_unlock(); 4470 put_online_cpus(); 4471 4472 return retval; 4473} 4474 4475/** 4476 * sys_sched_getaffinity - get the cpu affinity of a process 4477 * @pid: pid of the process 4478 * @len: length in bytes of the bitmask pointed to by user_mask_ptr 4479 * @user_mask_ptr: user-space pointer to hold the current cpu mask 4480 */ 4481SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len, 4482 unsigned long __user *, user_mask_ptr) 4483{ 4484 int ret; 4485 cpumask_var_t mask; 4486 4487 if ((len * BITS_PER_BYTE) < nr_cpu_ids) 4488 return -EINVAL; 4489 if (len & (sizeof(unsigned long)-1)) 4490 return -EINVAL; 4491 4492 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) 4493 return -ENOMEM; 4494 4495 ret = sched_getaffinity(pid, mask); 4496 if (ret == 0) { 4497 size_t retlen = min_t(size_t, len, cpumask_size()); 4498 4499 if (copy_to_user(user_mask_ptr, mask, retlen)) 4500 ret = -EFAULT; 4501 else 4502 ret = retlen; 4503 } 4504 free_cpumask_var(mask); 4505 4506 return ret; 4507} 4508 4509/** 4510 * sys_sched_yield - yield the current processor to other threads. 4511 * 4512 * This function yields the current CPU to other tasks. If there are no 4513 * other threads running on this CPU then this function will return. 4514 */ 4515SYSCALL_DEFINE0(sched_yield) 4516{ 4517 struct rq *rq = this_rq_lock(); 4518 4519 schedstat_inc(rq, yld_count); 4520 current->sched_class->yield_task(rq); 4521 4522 /* 4523 * Since we are going to call schedule() anyway, there's 4524 * no need to preempt or enable interrupts: 4525 */ 4526 __release(rq->lock); 4527 spin_release(&rq->lock.dep_map, 1, _THIS_IP_); 4528 do_raw_spin_unlock(&rq->lock); 4529 sched_preempt_enable_no_resched(); 4530 4531 schedule(); 4532 4533 return 0; 4534} 4535 4536static inline int should_resched(void) 4537{ 4538 return need_resched() && !(preempt_count() & PREEMPT_ACTIVE); 4539} 4540 4541static void __cond_resched(void) 4542{ 4543 add_preempt_count(PREEMPT_ACTIVE); 4544 __schedule(); 4545 sub_preempt_count(PREEMPT_ACTIVE); 4546} 4547 4548int __sched _cond_resched(void) 4549{ 4550 if (should_resched()) { 4551 __cond_resched(); 4552 return 1; 4553 } 4554 return 0; 4555} 4556EXPORT_SYMBOL(_cond_resched); 4557 4558/* 4559 * __cond_resched_lock() - if a reschedule is pending, drop the given lock, 4560 * call schedule, and on return reacquire the lock. 4561 * 4562 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level 4563 * operations here to prevent schedule() from being called twice (once via 4564 * spin_unlock(), once by hand). 4565 */ 4566int __cond_resched_lock(spinlock_t *lock) 4567{ 4568 int resched = should_resched(); 4569 int ret = 0; 4570 4571 lockdep_assert_held(lock); 4572 4573 if (spin_needbreak(lock) || resched) { 4574 spin_unlock(lock); 4575 if (resched) 4576 __cond_resched(); 4577 else 4578 cpu_relax(); 4579 ret = 1; 4580 spin_lock(lock); 4581 } 4582 return ret; 4583} 4584EXPORT_SYMBOL(__cond_resched_lock); 4585 4586int __sched __cond_resched_softirq(void) 4587{ 4588 BUG_ON(!in_softirq()); 4589 4590 if (should_resched()) { 4591 local_bh_enable(); 4592 __cond_resched(); 4593 local_bh_disable(); 4594 return 1; 4595 } 4596 return 0; 4597} 4598EXPORT_SYMBOL(__cond_resched_softirq); 4599 4600/** 4601 * yield - yield the current processor to other threads. 4602 * 4603 * Do not ever use this function, there's a 99% chance you're doing it wrong. 4604 * 4605 * The scheduler is at all times free to pick the calling task as the most 4606 * eligible task to run, if removing the yield() call from your code breaks 4607 * it, its already broken. 4608 * 4609 * Typical broken usage is: 4610 * 4611 * while (!event) 4612 * yield(); 4613 * 4614 * where one assumes that yield() will let 'the other' process run that will 4615 * make event true. If the current task is a SCHED_FIFO task that will never 4616 * happen. Never use yield() as a progress guarantee!! 4617 * 4618 * If you want to use yield() to wait for something, use wait_event(). 4619 * If you want to use yield() to be 'nice' for others, use cond_resched(). 4620 * If you still want to use yield(), do not! 4621 */ 4622void __sched yield(void) 4623{ 4624 set_current_state(TASK_RUNNING); 4625 sys_sched_yield(); 4626} 4627EXPORT_SYMBOL(yield); 4628 4629/** 4630 * yield_to - yield the current processor to another thread in 4631 * your thread group, or accelerate that thread toward the 4632 * processor it's on. 4633 * @p: target task 4634 * @preempt: whether task preemption is allowed or not 4635 * 4636 * It's the caller's job to ensure that the target task struct 4637 * can't go away on us before we can do any checks. 4638 * 4639 * Returns true if we indeed boosted the target task. 4640 */ 4641bool __sched yield_to(struct task_struct *p, bool preempt) 4642{ 4643 struct task_struct *curr = current; 4644 struct rq *rq, *p_rq; 4645 unsigned long flags; 4646 bool yielded = 0; 4647 4648 local_irq_save(flags); 4649 rq = this_rq(); 4650 4651again: 4652 p_rq = task_rq(p); 4653 double_rq_lock(rq, p_rq); 4654 while (task_rq(p) != p_rq) { 4655 double_rq_unlock(rq, p_rq); 4656 goto again; 4657 } 4658 4659 if (!curr->sched_class->yield_to_task) 4660 goto out; 4661 4662 if (curr->sched_class != p->sched_class) 4663 goto out; 4664 4665 if (task_running(p_rq, p) || p->state) 4666 goto out; 4667 4668 yielded = curr->sched_class->yield_to_task(rq, p, preempt); 4669 if (yielded) { 4670 schedstat_inc(rq, yld_count); 4671 /* 4672 * Make p's CPU reschedule; pick_next_entity takes care of 4673 * fairness. 4674 */ 4675 if (preempt && rq != p_rq) 4676 resched_task(p_rq->curr); 4677 } else { 4678 /* 4679 * We might have set it in task_yield_fair(), but are 4680 * not going to schedule(), so don't want to skip 4681 * the next update. 4682 */ 4683 rq->skip_clock_update = 0; 4684 } 4685 4686out: 4687 double_rq_unlock(rq, p_rq); 4688 local_irq_restore(flags); 4689 4690 if (yielded) 4691 schedule(); 4692 4693 return yielded; 4694} 4695EXPORT_SYMBOL_GPL(yield_to); 4696 4697/* 4698 * This task is about to go to sleep on IO. Increment rq->nr_iowait so 4699 * that process accounting knows that this is a task in IO wait state. 4700 */ 4701void __sched io_schedule(void) 4702{ 4703 struct rq *rq = raw_rq(); 4704 4705 delayacct_blkio_start(); 4706 atomic_inc(&rq->nr_iowait); 4707 blk_flush_plug(current); 4708 current->in_iowait = 1; 4709 schedule(); 4710 current->in_iowait = 0; 4711 atomic_dec(&rq->nr_iowait); 4712 delayacct_blkio_end(); 4713} 4714EXPORT_SYMBOL(io_schedule); 4715 4716long __sched io_schedule_timeout(long timeout) 4717{ 4718 struct rq *rq = raw_rq(); 4719 long ret; 4720 4721 delayacct_blkio_start(); 4722 atomic_inc(&rq->nr_iowait); 4723 blk_flush_plug(current); 4724 current->in_iowait = 1; 4725 ret = schedule_timeout(timeout); 4726 current->in_iowait = 0; 4727 atomic_dec(&rq->nr_iowait); 4728 delayacct_blkio_end(); 4729 return ret; 4730} 4731 4732/** 4733 * sys_sched_get_priority_max - return maximum RT priority. 4734 * @policy: scheduling class. 4735 * 4736 * this syscall returns the maximum rt_priority that can be used 4737 * by a given scheduling class. 4738 */ 4739SYSCALL_DEFINE1(sched_get_priority_max, int, policy) 4740{ 4741 int ret = -EINVAL; 4742 4743 switch (policy) { 4744 case SCHED_FIFO: 4745 case SCHED_RR: 4746 ret = MAX_USER_RT_PRIO-1; 4747 break; 4748 case SCHED_NORMAL: 4749 case SCHED_BATCH: 4750 case SCHED_IDLE: 4751 ret = 0; 4752 break; 4753 } 4754 return ret; 4755} 4756 4757/** 4758 * sys_sched_get_priority_min - return minimum RT priority. 4759 * @policy: scheduling class. 4760 * 4761 * this syscall returns the minimum rt_priority that can be used 4762 * by a given scheduling class. 4763 */ 4764SYSCALL_DEFINE1(sched_get_priority_min, int, policy) 4765{ 4766 int ret = -EINVAL; 4767 4768 switch (policy) { 4769 case SCHED_FIFO: 4770 case SCHED_RR: 4771 ret = 1; 4772 break; 4773 case SCHED_NORMAL: 4774 case SCHED_BATCH: 4775 case SCHED_IDLE: 4776 ret = 0; 4777 } 4778 return ret; 4779} 4780 4781/** 4782 * sys_sched_rr_get_interval - return the default timeslice of a process. 4783 * @pid: pid of the process. 4784 * @interval: userspace pointer to the timeslice value. 4785 * 4786 * this syscall writes the default timeslice value of a given process 4787 * into the user-space timespec buffer. A value of '0' means infinity. 4788 */ 4789SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid, 4790 struct timespec __user *, interval) 4791{ 4792 struct task_struct *p; 4793 unsigned int time_slice; 4794 unsigned long flags; 4795 struct rq *rq; 4796 int retval; 4797 struct timespec t; 4798 4799 if (pid < 0) 4800 return -EINVAL; 4801 4802 retval = -ESRCH; 4803 rcu_read_lock(); 4804 p = find_process_by_pid(pid); 4805 if (!p) 4806 goto out_unlock; 4807 4808 retval = security_task_getscheduler(p); 4809 if (retval) 4810 goto out_unlock; 4811 4812 rq = task_rq_lock(p, &flags); 4813 time_slice = p->sched_class->get_rr_interval(rq, p); 4814 task_rq_unlock(rq, p, &flags); 4815 4816 rcu_read_unlock(); 4817 jiffies_to_timespec(time_slice, &t); 4818 retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; 4819 return retval; 4820 4821out_unlock: 4822 rcu_read_unlock(); 4823 return retval; 4824} 4825 4826static const char stat_nam[] = TASK_STATE_TO_CHAR_STR; 4827 4828void sched_show_task(struct task_struct *p) 4829{ 4830 unsigned long free = 0; 4831 unsigned state; 4832 4833 state = p->state ? __ffs(p->state) + 1 : 0; 4834 printk(KERN_INFO "%-15.15s %c", p->comm, 4835 state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); 4836#if BITS_PER_LONG == 32 4837 if (state == TASK_RUNNING) 4838 printk(KERN_CONT " running "); 4839 else 4840 printk(KERN_CONT " %08lx ", thread_saved_pc(p)); 4841#else 4842 if (state == TASK_RUNNING) 4843 printk(KERN_CONT " running task "); 4844 else 4845 printk(KERN_CONT " %016lx ", thread_saved_pc(p)); 4846#endif 4847#ifdef CONFIG_DEBUG_STACK_USAGE 4848 free = stack_not_used(p); 4849#endif 4850 printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free, 4851 task_pid_nr(p), task_pid_nr(rcu_dereference(p->real_parent)), 4852 (unsigned long)task_thread_info(p)->flags); 4853 4854 show_stack(p, NULL); 4855} 4856 4857void show_state_filter(unsigned long state_filter) 4858{ 4859 struct task_struct *g, *p; 4860 4861#if BITS_PER_LONG == 32 4862 printk(KERN_INFO 4863 " task PC stack pid father\n"); 4864#else 4865 printk(KERN_INFO 4866 " task PC stack pid father\n"); 4867#endif 4868 rcu_read_lock(); 4869 do_each_thread(g, p) { 4870 /* 4871 * reset the NMI-timeout, listing all files on a slow 4872 * console might take a lot of time: 4873 */ 4874 touch_nmi_watchdog(); 4875 if (!state_filter || (p->state & state_filter)) 4876 sched_show_task(p); 4877 } while_each_thread(g, p); 4878 4879 touch_all_softlockup_watchdogs(); 4880 4881#ifdef CONFIG_SCHED_DEBUG 4882 sysrq_sched_debug_show(); 4883#endif 4884 rcu_read_unlock(); 4885 /* 4886 * Only show locks if all tasks are dumped: 4887 */ 4888 if (!state_filter) 4889 debug_show_all_locks(); 4890} 4891 4892void __cpuinit init_idle_bootup_task(struct task_struct *idle) 4893{ 4894 idle->sched_class = &idle_sched_class; 4895} 4896 4897/** 4898 * init_idle - set up an idle thread for a given CPU 4899 * @idle: task in question 4900 * @cpu: cpu the idle task belongs to 4901 * 4902 * NOTE: this function does not set the idle thread's NEED_RESCHED 4903 * flag, to make booting more robust. 4904 */ 4905void __cpuinit init_idle(struct task_struct *idle, int cpu) 4906{ 4907 struct rq *rq = cpu_rq(cpu); 4908 unsigned long flags; 4909 4910 raw_spin_lock_irqsave(&rq->lock, flags); 4911 4912 __sched_fork(idle); 4913 idle->state = TASK_RUNNING; 4914 idle->se.exec_start = sched_clock(); 4915 4916 do_set_cpus_allowed(idle, cpumask_of(cpu)); 4917 /* 4918 * We're having a chicken and egg problem, even though we are 4919 * holding rq->lock, the cpu isn't yet set to this cpu so the 4920 * lockdep check in task_group() will fail. 4921 * 4922 * Similar case to sched_fork(). / Alternatively we could 4923 * use task_rq_lock() here and obtain the other rq->lock. 4924 * 4925 * Silence PROVE_RCU 4926 */ 4927 rcu_read_lock(); 4928 __set_task_cpu(idle, cpu); 4929 rcu_read_unlock(); 4930 4931 rq->curr = rq->idle = idle; 4932#if defined(CONFIG_SMP) 4933 idle->on_cpu = 1; 4934#endif 4935 raw_spin_unlock_irqrestore(&rq->lock, flags); 4936 4937 /* Set the preempt count _outside_ the spinlocks! */ 4938 task_thread_info(idle)->preempt_count = 0; 4939 4940 /* 4941 * The idle tasks have their own, simple scheduling class: 4942 */ 4943 idle->sched_class = &idle_sched_class; 4944 ftrace_graph_init_idle_task(idle, cpu); 4945#if defined(CONFIG_SMP) 4946 sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu); 4947#endif 4948} 4949 4950#ifdef CONFIG_SMP 4951void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) 4952{ 4953 if (p->sched_class && p->sched_class->set_cpus_allowed) 4954 p->sched_class->set_cpus_allowed(p, new_mask); 4955 4956 cpumask_copy(&p->cpus_allowed, new_mask); 4957 p->rt.nr_cpus_allowed = cpumask_weight(new_mask); 4958} 4959 4960/* 4961 * This is how migration works: 4962 * 4963 * 1) we invoke migration_cpu_stop() on the target CPU using 4964 * stop_one_cpu(). 4965 * 2) stopper starts to run (implicitly forcing the migrated thread 4966 * off the CPU) 4967 * 3) it checks whether the migrated task is still in the wrong runqueue. 4968 * 4) if it's in the wrong runqueue then the migration thread removes 4969 * it and puts it into the right queue. 4970 * 5) stopper completes and stop_one_cpu() returns and the migration 4971 * is done. 4972 */ 4973 4974/* 4975 * Change a given task's CPU affinity. Migrate the thread to a 4976 * proper CPU and schedule it away if the CPU it's executing on 4977 * is removed from the allowed bitmask. 4978 * 4979 * NOTE: the caller must have a valid reference to the task, the 4980 * task must not exit() & deallocate itself prematurely. The 4981 * call is not atomic; no spinlocks may be held. 4982 */ 4983int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) 4984{ 4985 unsigned long flags; 4986 struct rq *rq; 4987 unsigned int dest_cpu; 4988 int ret = 0; 4989 4990 rq = task_rq_lock(p, &flags); 4991 4992 if (cpumask_equal(&p->cpus_allowed, new_mask)) 4993 goto out; 4994 4995 if (!cpumask_intersects(new_mask, cpu_active_mask)) { 4996 ret = -EINVAL; 4997 goto out; 4998 } 4999 5000 if (unlikely((p->flags & PF_THREAD_BOUND) && p != current)) { 5001 ret = -EINVAL; 5002 goto out; 5003 } 5004 5005 do_set_cpus_allowed(p, new_mask); 5006 5007 /* Can the task run on the task's current CPU? If so, we're done */ 5008 if (cpumask_test_cpu(task_cpu(p), new_mask)) 5009 goto out; 5010 5011 dest_cpu = cpumask_any_and(cpu_active_mask, new_mask); 5012 if (p->on_rq) { 5013 struct migration_arg arg = { p, dest_cpu }; 5014 /* Need help from migration thread: drop lock and wait. */ 5015 task_rq_unlock(rq, p, &flags); 5016 stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg); 5017 tlb_migrate_finish(p->mm); 5018 return 0; 5019 } 5020out: 5021 task_rq_unlock(rq, p, &flags); 5022 5023 return ret; 5024} 5025EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr); 5026 5027/* 5028 * Move (not current) task off this cpu, onto dest cpu. We're doing 5029 * this because either it can't run here any more (set_cpus_allowed() 5030 * away from this CPU, or CPU going down), or because we're 5031 * attempting to rebalance this task on exec (sched_exec). 5032 * 5033 * So we race with normal scheduler movements, but that's OK, as long 5034 * as the task is no longer on this CPU. 5035 * 5036 * Returns non-zero if task was successfully migrated. 5037 */ 5038static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) 5039{ 5040 struct rq *rq_dest, *rq_src; 5041 int ret = 0; 5042 5043 if (unlikely(!cpu_active(dest_cpu))) 5044 return ret; 5045 5046 rq_src = cpu_rq(src_cpu); 5047 rq_dest = cpu_rq(dest_cpu); 5048 5049 raw_spin_lock(&p->pi_lock); 5050 double_rq_lock(rq_src, rq_dest); 5051 /* Already moved. */ 5052 if (task_cpu(p) != src_cpu) 5053 goto done; 5054 /* Affinity changed (again). */ 5055 if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) 5056 goto fail; 5057 5058 /* 5059 * If we're not on a rq, the next wake-up will ensure we're 5060 * placed properly. 5061 */ 5062 if (p->on_rq) { 5063 dequeue_task(rq_src, p, 0); 5064 set_task_cpu(p, dest_cpu); 5065 enqueue_task(rq_dest, p, 0); 5066 check_preempt_curr(rq_dest, p, 0); 5067 } 5068done: 5069 ret = 1; 5070fail: 5071 double_rq_unlock(rq_src, rq_dest); 5072 raw_spin_unlock(&p->pi_lock); 5073 return ret; 5074} 5075 5076/* 5077 * migration_cpu_stop - this will be executed by a highprio stopper thread 5078 * and performs thread migration by bumping thread off CPU then 5079 * 'pushing' onto another runqueue. 5080 */ 5081static int migration_cpu_stop(void *data) 5082{ 5083 struct migration_arg *arg = data; 5084 5085 /* 5086 * The original target cpu might have gone down and we might 5087 * be on another cpu but it doesn't matter. 5088 */ 5089 local_irq_disable(); 5090 __migrate_task(arg->task, raw_smp_processor_id(), arg->dest_cpu); 5091 local_irq_enable(); 5092 return 0; 5093} 5094 5095#ifdef CONFIG_HOTPLUG_CPU 5096 5097/* 5098 * Ensures that the idle task is using init_mm right before its cpu goes 5099 * offline. 5100 */ 5101void idle_task_exit(void) 5102{ 5103 struct mm_struct *mm = current->active_mm; 5104 5105 BUG_ON(cpu_online(smp_processor_id())); 5106 5107 if (mm != &init_mm) 5108 switch_mm(mm, &init_mm, current); 5109 mmdrop(mm); 5110} 5111 5112/* 5113 * While a dead CPU has no uninterruptible tasks queued at this point, 5114 * it might still have a nonzero ->nr_uninterruptible counter, because 5115 * for performance reasons the counter is not stricly tracking tasks to 5116 * their home CPUs. So we just add the counter to another CPU's counter, 5117 * to keep the global sum constant after CPU-down: 5118 */ 5119static void migrate_nr_uninterruptible(struct rq *rq_src) 5120{ 5121 struct rq *rq_dest = cpu_rq(cpumask_any(cpu_active_mask)); 5122 5123 rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible; 5124 rq_src->nr_uninterruptible = 0; 5125} 5126 5127/* 5128 * remove the tasks which were accounted by rq from calc_load_tasks. 5129 */ 5130static void calc_global_load_remove(struct rq *rq) 5131{ 5132 atomic_long_sub(rq->calc_load_active, &calc_load_tasks); 5133 rq->calc_load_active = 0; 5134} 5135 5136/* 5137 * Migrate all tasks from the rq, sleeping tasks will be migrated by 5138 * try_to_wake_up()->select_task_rq(). 5139 * 5140 * Called with rq->lock held even though we'er in stop_machine() and 5141 * there's no concurrency possible, we hold the required locks anyway 5142 * because of lock validation efforts. 5143 */ 5144static void migrate_tasks(unsigned int dead_cpu) 5145{ 5146 struct rq *rq = cpu_rq(dead_cpu); 5147 struct task_struct *next, *stop = rq->stop; 5148 int dest_cpu; 5149 5150 /* 5151 * Fudge the rq selection such that the below task selection loop 5152 * doesn't get stuck on the currently eligible stop task. 5153 * 5154 * We're currently inside stop_machine() and the rq is either stuck 5155 * in the stop_machine_cpu_stop() loop, or we're executing this code, 5156 * either way we should never end up calling schedule() until we're 5157 * done here. 5158 */ 5159 rq->stop = NULL; 5160 5161 /* Ensure any throttled groups are reachable by pick_next_task */ 5162 unthrottle_offline_cfs_rqs(rq); 5163 5164 for ( ; ; ) { 5165 /* 5166 * There's this thread running, bail when that's the only 5167 * remaining thread. 5168 */ 5169 if (rq->nr_running == 1) 5170 break; 5171 5172 next = pick_next_task(rq); 5173 BUG_ON(!next); 5174 next->sched_class->put_prev_task(rq, next); 5175 5176 /* Find suitable destination for @next, with force if needed. */ 5177 dest_cpu = select_fallback_rq(dead_cpu, next); 5178 raw_spin_unlock(&rq->lock); 5179 5180 __migrate_task(next, dead_cpu, dest_cpu); 5181 5182 raw_spin_lock(&rq->lock); 5183 } 5184 5185 rq->stop = stop; 5186} 5187 5188#endif /* CONFIG_HOTPLUG_CPU */ 5189 5190#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL) 5191 5192static struct ctl_table sd_ctl_dir[] = { 5193 { 5194 .procname = "sched_domain", 5195 .mode = 0555, 5196 }, 5197 {} 5198}; 5199 5200static struct ctl_table sd_ctl_root[] = { 5201 { 5202 .procname = "kernel", 5203 .mode = 0555, 5204 .child = sd_ctl_dir, 5205 }, 5206 {} 5207}; 5208 5209static struct ctl_table *sd_alloc_ctl_entry(int n) 5210{ 5211 struct ctl_table *entry = 5212 kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL); 5213 5214 return entry; 5215} 5216 5217static void sd_free_ctl_entry(struct ctl_table **tablep) 5218{ 5219 struct ctl_table *entry; 5220 5221 /* 5222 * In the intermediate directories, both the child directory and 5223 * procname are dynamically allocated and could fail but the mode 5224 * will always be set. In the lowest directory the names are 5225 * static strings and all have proc handlers. 5226 */ 5227 for (entry = *tablep; entry->mode; entry++) { 5228 if (entry->child) 5229 sd_free_ctl_entry(&entry->child); 5230 if (entry->proc_handler == NULL) 5231 kfree(entry->procname); 5232 } 5233 5234 kfree(*tablep); 5235 *tablep = NULL; 5236} 5237 5238static void 5239set_table_entry(struct ctl_table *entry, 5240 const char *procname, void *data, int maxlen, 5241 umode_t mode, proc_handler *proc_handler) 5242{ 5243 entry->procname = procname; 5244 entry->data = data; 5245 entry->maxlen = maxlen; 5246 entry->mode = mode; 5247 entry->proc_handler = proc_handler; 5248} 5249 5250static struct ctl_table * 5251sd_alloc_ctl_domain_table(struct sched_domain *sd) 5252{ 5253 struct ctl_table *table = sd_alloc_ctl_entry(13); 5254 5255 if (table == NULL) 5256 return NULL; 5257 5258 set_table_entry(&table[0], "min_interval", &sd->min_interval, 5259 sizeof(long), 0644, proc_doulongvec_minmax); 5260 set_table_entry(&table[1], "max_interval", &sd->max_interval, 5261 sizeof(long), 0644, proc_doulongvec_minmax); 5262 set_table_entry(&table[2], "busy_idx", &sd->busy_idx, 5263 sizeof(int), 0644, proc_dointvec_minmax); 5264 set_table_entry(&table[3], "idle_idx", &sd->idle_idx, 5265 sizeof(int), 0644, proc_dointvec_minmax); 5266 set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx, 5267 sizeof(int), 0644, proc_dointvec_minmax); 5268 set_table_entry(&table[5], "wake_idx", &sd->wake_idx, 5269 sizeof(int), 0644, proc_dointvec_minmax); 5270 set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx, 5271 sizeof(int), 0644, proc_dointvec_minmax); 5272 set_table_entry(&table[7], "busy_factor", &sd->busy_factor, 5273 sizeof(int), 0644, proc_dointvec_minmax); 5274 set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct, 5275 sizeof(int), 0644, proc_dointvec_minmax); 5276 set_table_entry(&table[9], "cache_nice_tries", 5277 &sd->cache_nice_tries, 5278 sizeof(int), 0644, proc_dointvec_minmax); 5279 set_table_entry(&table[10], "flags", &sd->flags, 5280 sizeof(int), 0644, proc_dointvec_minmax); 5281 set_table_entry(&table[11], "name", sd->name, 5282 CORENAME_MAX_SIZE, 0444, proc_dostring); 5283 /* &table[12] is terminator */ 5284 5285 return table; 5286} 5287 5288static ctl_table *sd_alloc_ctl_cpu_table(int cpu) 5289{ 5290 struct ctl_table *entry, *table; 5291 struct sched_domain *sd; 5292 int domain_num = 0, i; 5293 char buf[32]; 5294 5295 for_each_domain(cpu, sd) 5296 domain_num++; 5297 entry = table = sd_alloc_ctl_entry(domain_num + 1); 5298 if (table == NULL) 5299 return NULL; 5300 5301 i = 0; 5302 for_each_domain(cpu, sd) { 5303 snprintf(buf, 32, "domain%d", i); 5304 entry->procname = kstrdup(buf, GFP_KERNEL); 5305 entry->mode = 0555; 5306 entry->child = sd_alloc_ctl_domain_table(sd); 5307 entry++; 5308 i++; 5309 } 5310 return table; 5311} 5312 5313static struct ctl_table_header *sd_sysctl_header; 5314static void register_sched_domain_sysctl(void) 5315{ 5316 int i, cpu_num = num_possible_cpus(); 5317 struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1); 5318 char buf[32]; 5319 5320 WARN_ON(sd_ctl_dir[0].child); 5321 sd_ctl_dir[0].child = entry; 5322 5323 if (entry == NULL) 5324 return; 5325 5326 for_each_possible_cpu(i) { 5327 snprintf(buf, 32, "cpu%d", i); 5328 entry->procname = kstrdup(buf, GFP_KERNEL); 5329 entry->mode = 0555; 5330 entry->child = sd_alloc_ctl_cpu_table(i); 5331 entry++; 5332 } 5333 5334 WARN_ON(sd_sysctl_header); 5335 sd_sysctl_header = register_sysctl_table(sd_ctl_root); 5336} 5337 5338/* may be called multiple times per register */ 5339static void unregister_sched_domain_sysctl(void) 5340{ 5341 if (sd_sysctl_header) 5342 unregister_sysctl_table(sd_sysctl_header); 5343 sd_sysctl_header = NULL; 5344 if (sd_ctl_dir[0].child) 5345 sd_free_ctl_entry(&sd_ctl_dir[0].child); 5346} 5347#else 5348static void register_sched_domain_sysctl(void) 5349{ 5350} 5351static void unregister_sched_domain_sysctl(void) 5352{ 5353} 5354#endif 5355 5356static void set_rq_online(struct rq *rq) 5357{ 5358 if (!rq->online) { 5359 const struct sched_class *class; 5360 5361 cpumask_set_cpu(rq->cpu, rq->rd->online); 5362 rq->online = 1; 5363 5364 for_each_class(class) { 5365 if (class->rq_online) 5366 class->rq_online(rq); 5367 } 5368 } 5369} 5370 5371static void set_rq_offline(struct rq *rq) 5372{ 5373 if (rq->online) { 5374 const struct sched_class *class; 5375 5376 for_each_class(class) { 5377 if (class->rq_offline) 5378 class->rq_offline(rq); 5379 } 5380 5381 cpumask_clear_cpu(rq->cpu, rq->rd->online); 5382 rq->online = 0; 5383 } 5384} 5385 5386/* 5387 * migration_call - callback that gets triggered when a CPU is added. 5388 * Here we can start up the necessary migration thread for the new CPU. 5389 */ 5390static int __cpuinit 5391migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) 5392{ 5393 int cpu = (long)hcpu; 5394 unsigned long flags; 5395 struct rq *rq = cpu_rq(cpu); 5396 5397 switch (action & ~CPU_TASKS_FROZEN) { 5398 5399 case CPU_UP_PREPARE: 5400 rq->calc_load_update = calc_load_update; 5401 break; 5402 5403 case CPU_ONLINE: 5404 /* Update our root-domain */ 5405 raw_spin_lock_irqsave(&rq->lock, flags); 5406 if (rq->rd) { 5407 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); 5408 5409 set_rq_online(rq); 5410 } 5411 raw_spin_unlock_irqrestore(&rq->lock, flags); 5412 break; 5413 5414#ifdef CONFIG_HOTPLUG_CPU 5415 case CPU_DYING: 5416 sched_ttwu_pending(); 5417 /* Update our root-domain */ 5418 raw_spin_lock_irqsave(&rq->lock, flags); 5419 if (rq->rd) { 5420 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); 5421 set_rq_offline(rq); 5422 } 5423 migrate_tasks(cpu); 5424 BUG_ON(rq->nr_running != 1); /* the migration thread */ 5425 raw_spin_unlock_irqrestore(&rq->lock, flags); 5426 5427 migrate_nr_uninterruptible(rq); 5428 calc_global_load_remove(rq); 5429 break; 5430#endif 5431 } 5432 5433 update_max_interval(); 5434 5435 return NOTIFY_OK; 5436} 5437 5438/* 5439 * Register at high priority so that task migration (migrate_all_tasks) 5440 * happens before everything else. This has to be lower priority than 5441 * the notifier in the perf_event subsystem, though. 5442 */ 5443static struct notifier_block __cpuinitdata migration_notifier = { 5444 .notifier_call = migration_call, 5445 .priority = CPU_PRI_MIGRATION, 5446}; 5447 5448static int __cpuinit sched_cpu_active(struct notifier_block *nfb, 5449 unsigned long action, void *hcpu) 5450{ 5451 switch (action & ~CPU_TASKS_FROZEN) { 5452 case CPU_STARTING: 5453 case CPU_DOWN_FAILED: 5454 set_cpu_active((long)hcpu, true); 5455 return NOTIFY_OK; 5456 default: 5457 return NOTIFY_DONE; 5458 } 5459} 5460 5461static int __cpuinit sched_cpu_inactive(struct notifier_block *nfb, 5462 unsigned long action, void *hcpu) 5463{ 5464 switch (action & ~CPU_TASKS_FROZEN) { 5465 case CPU_DOWN_PREPARE: 5466 set_cpu_active((long)hcpu, false); 5467 return NOTIFY_OK; 5468 default: 5469 return NOTIFY_DONE; 5470 } 5471} 5472 5473static int __init migration_init(void) 5474{ 5475 void *cpu = (void *)(long)smp_processor_id(); 5476 int err; 5477 5478 /* Initialize migration for the boot CPU */ 5479 err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); 5480 BUG_ON(err == NOTIFY_BAD); 5481 migration_call(&migration_notifier, CPU_ONLINE, cpu); 5482 register_cpu_notifier(&migration_notifier); 5483 5484 /* Register cpu active notifiers */ 5485 cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE); 5486 cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE); 5487 5488 return 0; 5489} 5490early_initcall(migration_init); 5491#endif 5492 5493#ifdef CONFIG_SMP 5494 5495static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */ 5496 5497#ifdef CONFIG_SCHED_DEBUG 5498 5499static __read_mostly int sched_domain_debug_enabled; 5500 5501static int __init sched_domain_debug_setup(char *str) 5502{ 5503 sched_domain_debug_enabled = 1; 5504 5505 return 0; 5506} 5507early_param("sched_debug", sched_domain_debug_setup); 5508 5509static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, 5510 struct cpumask *groupmask) 5511{ 5512 struct sched_group *group = sd->groups; 5513 char str[256]; 5514 5515 cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd)); 5516 cpumask_clear(groupmask); 5517 5518 printk(KERN_DEBUG "%*s domain %d: ", level, "", level); 5519 5520 if (!(sd->flags & SD_LOAD_BALANCE)) { 5521 printk("does not load-balance\n"); 5522 if (sd->parent) 5523 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain" 5524 " has parent"); 5525 return -1; 5526 } 5527 5528 printk(KERN_CONT "span %s level %s\n", str, sd->name); 5529 5530 if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) { 5531 printk(KERN_ERR "ERROR: domain->span does not contain " 5532 "CPU%d\n", cpu); 5533 } 5534 if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) { 5535 printk(KERN_ERR "ERROR: domain->groups does not contain" 5536 " CPU%d\n", cpu); 5537 } 5538 5539 printk(KERN_DEBUG "%*s groups:", level + 1, ""); 5540 do { 5541 if (!group) { 5542 printk("\n"); 5543 printk(KERN_ERR "ERROR: group is NULL\n"); 5544 break; 5545 } 5546 5547 if (!group->sgp->power) { 5548 printk(KERN_CONT "\n"); 5549 printk(KERN_ERR "ERROR: domain->cpu_power not " 5550 "set\n"); 5551 break; 5552 } 5553 5554 if (!cpumask_weight(sched_group_cpus(group))) { 5555 printk(KERN_CONT "\n"); 5556 printk(KERN_ERR "ERROR: empty group\n"); 5557 break; 5558 } 5559 5560 if (cpumask_intersects(groupmask, sched_group_cpus(group))) { 5561 printk(KERN_CONT "\n"); 5562 printk(KERN_ERR "ERROR: repeated CPUs\n"); 5563 break; 5564 } 5565 5566 cpumask_or(groupmask, groupmask, sched_group_cpus(group)); 5567 5568 cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group)); 5569 5570 printk(KERN_CONT " %s", str); 5571 if (group->sgp->power != SCHED_POWER_SCALE) { 5572 printk(KERN_CONT " (cpu_power = %d)", 5573 group->sgp->power); 5574 } 5575 5576 group = group->next; 5577 } while (group != sd->groups); 5578 printk(KERN_CONT "\n"); 5579 5580 if (!cpumask_equal(sched_domain_span(sd), groupmask)) 5581 printk(KERN_ERR "ERROR: groups don't span domain->span\n"); 5582 5583 if (sd->parent && 5584 !cpumask_subset(groupmask, sched_domain_span(sd->parent))) 5585 printk(KERN_ERR "ERROR: parent span is not a superset " 5586 "of domain->span\n"); 5587 return 0; 5588} 5589 5590static void sched_domain_debug(struct sched_domain *sd, int cpu) 5591{ 5592 int level = 0; 5593 5594 if (!sched_domain_debug_enabled) 5595 return; 5596 5597 if (!sd) { 5598 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); 5599 return; 5600 } 5601 5602 printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); 5603 5604 for (;;) { 5605 if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask)) 5606 break; 5607 level++; 5608 sd = sd->parent; 5609 if (!sd) 5610 break; 5611 } 5612} 5613#else /* !CONFIG_SCHED_DEBUG */ 5614# define sched_domain_debug(sd, cpu) do { } while (0) 5615#endif /* CONFIG_SCHED_DEBUG */ 5616 5617static int sd_degenerate(struct sched_domain *sd) 5618{ 5619 if (cpumask_weight(sched_domain_span(sd)) == 1) 5620 return 1; 5621 5622 /* Following flags need at least 2 groups */ 5623 if (sd->flags & (SD_LOAD_BALANCE | 5624 SD_BALANCE_NEWIDLE | 5625 SD_BALANCE_FORK | 5626 SD_BALANCE_EXEC | 5627 SD_SHARE_CPUPOWER | 5628 SD_SHARE_PKG_RESOURCES)) { 5629 if (sd->groups != sd->groups->next) 5630 return 0; 5631 } 5632 5633 /* Following flags don't use groups */ 5634 if (sd->flags & (SD_WAKE_AFFINE)) 5635 return 0; 5636 5637 return 1; 5638} 5639 5640static int 5641sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) 5642{ 5643 unsigned long cflags = sd->flags, pflags = parent->flags; 5644 5645 if (sd_degenerate(parent)) 5646 return 1; 5647 5648 if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent))) 5649 return 0; 5650 5651 /* Flags needing groups don't count if only 1 group in parent */ 5652 if (parent->groups == parent->groups->next) { 5653 pflags &= ~(SD_LOAD_BALANCE | 5654 SD_BALANCE_NEWIDLE | 5655 SD_BALANCE_FORK | 5656 SD_BALANCE_EXEC | 5657 SD_SHARE_CPUPOWER | 5658 SD_SHARE_PKG_RESOURCES); 5659 if (nr_node_ids == 1) 5660 pflags &= ~SD_SERIALIZE; 5661 } 5662 if (~cflags & pflags) 5663 return 0; 5664 5665 return 1; 5666} 5667 5668static void free_rootdomain(struct rcu_head *rcu) 5669{ 5670 struct root_domain *rd = container_of(rcu, struct root_domain, rcu); 5671 5672 cpupri_cleanup(&rd->cpupri); 5673 free_cpumask_var(rd->rto_mask); 5674 free_cpumask_var(rd->online); 5675 free_cpumask_var(rd->span); 5676 kfree(rd); 5677} 5678 5679static void rq_attach_root(struct rq *rq, struct root_domain *rd) 5680{ 5681 struct root_domain *old_rd = NULL; 5682 unsigned long flags; 5683 5684 raw_spin_lock_irqsave(&rq->lock, flags); 5685 5686 if (rq->rd) { 5687 old_rd = rq->rd; 5688 5689 if (cpumask_test_cpu(rq->cpu, old_rd->online)) 5690 set_rq_offline(rq); 5691 5692 cpumask_clear_cpu(rq->cpu, old_rd->span); 5693 5694 /* 5695 * If we dont want to free the old_rt yet then 5696 * set old_rd to NULL to skip the freeing later 5697 * in this function: 5698 */ 5699 if (!atomic_dec_and_test(&old_rd->refcount)) 5700 old_rd = NULL; 5701 } 5702 5703 atomic_inc(&rd->refcount); 5704 rq->rd = rd; 5705 5706 cpumask_set_cpu(rq->cpu, rd->span); 5707 if (cpumask_test_cpu(rq->cpu, cpu_active_mask)) 5708 set_rq_online(rq); 5709 5710 raw_spin_unlock_irqrestore(&rq->lock, flags); 5711 5712 if (old_rd) 5713 call_rcu_sched(&old_rd->rcu, free_rootdomain); 5714} 5715 5716static int init_rootdomain(struct root_domain *rd) 5717{ 5718 memset(rd, 0, sizeof(*rd)); 5719 5720 if (!alloc_cpumask_var(&rd->span, GFP_KERNEL)) 5721 goto out; 5722 if (!alloc_cpumask_var(&rd->online, GFP_KERNEL)) 5723 goto free_span; 5724 if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL)) 5725 goto free_online; 5726 5727 if (cpupri_init(&rd->cpupri) != 0) 5728 goto free_rto_mask; 5729 return 0; 5730 5731free_rto_mask: 5732 free_cpumask_var(rd->rto_mask); 5733free_online: 5734 free_cpumask_var(rd->online); 5735free_span: 5736 free_cpumask_var(rd->span); 5737out: 5738 return -ENOMEM; 5739} 5740 5741/* 5742 * By default the system creates a single root-domain with all cpus as 5743 * members (mimicking the global state we have today). 5744 */ 5745struct root_domain def_root_domain; 5746 5747static void init_defrootdomain(void) 5748{ 5749 init_rootdomain(&def_root_domain); 5750 5751 atomic_set(&def_root_domain.refcount, 1); 5752} 5753 5754static struct root_domain *alloc_rootdomain(void) 5755{ 5756 struct root_domain *rd; 5757 5758 rd = kmalloc(sizeof(*rd), GFP_KERNEL); 5759 if (!rd) 5760 return NULL; 5761 5762 if (init_rootdomain(rd) != 0) { 5763 kfree(rd); 5764 return NULL; 5765 } 5766 5767 return rd; 5768} 5769 5770static void free_sched_groups(struct sched_group *sg, int free_sgp) 5771{ 5772 struct sched_group *tmp, *first; 5773 5774 if (!sg) 5775 return; 5776 5777 first = sg; 5778 do { 5779 tmp = sg->next; 5780 5781 if (free_sgp && atomic_dec_and_test(&sg->sgp->ref)) 5782 kfree(sg->sgp); 5783 5784 kfree(sg); 5785 sg = tmp; 5786 } while (sg != first); 5787} 5788 5789static void free_sched_domain(struct rcu_head *rcu) 5790{ 5791 struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu); 5792 5793 /* 5794 * If its an overlapping domain it has private groups, iterate and 5795 * nuke them all. 5796 */ 5797 if (sd->flags & SD_OVERLAP) { 5798 free_sched_groups(sd->groups, 1); 5799 } else if (atomic_dec_and_test(&sd->groups->ref)) { 5800 kfree(sd->groups->sgp); 5801 kfree(sd->groups); 5802 } 5803 kfree(sd); 5804} 5805 5806static void destroy_sched_domain(struct sched_domain *sd, int cpu) 5807{ 5808 call_rcu(&sd->rcu, free_sched_domain); 5809} 5810 5811static void destroy_sched_domains(struct sched_domain *sd, int cpu) 5812{ 5813 for (; sd; sd = sd->parent) 5814 destroy_sched_domain(sd, cpu); 5815} 5816 5817/* 5818 * Keep a special pointer to the highest sched_domain that has 5819 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this 5820 * allows us to avoid some pointer chasing select_idle_sibling(). 5821 * 5822 * Also keep a unique ID per domain (we use the first cpu number in 5823 * the cpumask of the domain), this allows us to quickly tell if 5824 * two cpus are in the same cache domain, see cpus_share_cache(). 5825 */ 5826DEFINE_PER_CPU(struct sched_domain *, sd_llc); 5827DEFINE_PER_CPU(int, sd_llc_id); 5828 5829static void update_top_cache_domain(int cpu) 5830{ 5831 struct sched_domain *sd; 5832 int id = cpu; 5833 5834 sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES); 5835 if (sd) 5836 id = cpumask_first(sched_domain_span(sd)); 5837 5838 rcu_assign_pointer(per_cpu(sd_llc, cpu), sd); 5839 per_cpu(sd_llc_id, cpu) = id; 5840} 5841 5842/* 5843 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must 5844 * hold the hotplug lock. 5845 */ 5846static void 5847cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) 5848{ 5849 struct rq *rq = cpu_rq(cpu); 5850 struct sched_domain *tmp; 5851 5852 /* Remove the sched domains which do not contribute to scheduling. */ 5853 for (tmp = sd; tmp; ) { 5854 struct sched_domain *parent = tmp->parent; 5855 if (!parent) 5856 break; 5857 5858 if (sd_parent_degenerate(tmp, parent)) { 5859 tmp->parent = parent->parent; 5860 if (parent->parent) 5861 parent->parent->child = tmp; 5862 destroy_sched_domain(parent, cpu); 5863 } else 5864 tmp = tmp->parent; 5865 } 5866 5867 if (sd && sd_degenerate(sd)) { 5868 tmp = sd; 5869 sd = sd->parent; 5870 destroy_sched_domain(tmp, cpu); 5871 if (sd) 5872 sd->child = NULL; 5873 } 5874 5875 sched_domain_debug(sd, cpu); 5876 5877 rq_attach_root(rq, rd); 5878 tmp = rq->sd; 5879 rcu_assign_pointer(rq->sd, sd); 5880 destroy_sched_domains(tmp, cpu); 5881 5882 update_top_cache_domain(cpu); 5883} 5884 5885/* cpus with isolated domains */ 5886static cpumask_var_t cpu_isolated_map; 5887 5888/* Setup the mask of cpus configured for isolated domains */ 5889static int __init isolated_cpu_setup(char *str) 5890{ 5891 alloc_bootmem_cpumask_var(&cpu_isolated_map); 5892 cpulist_parse(str, cpu_isolated_map); 5893 return 1; 5894} 5895 5896__setup("isolcpus=", isolated_cpu_setup); 5897 5898#ifdef CONFIG_NUMA 5899 5900/** 5901 * find_next_best_node - find the next node to include in a sched_domain 5902 * @node: node whose sched_domain we're building 5903 * @used_nodes: nodes already in the sched_domain 5904 * 5905 * Find the next node to include in a given scheduling domain. Simply 5906 * finds the closest node not already in the @used_nodes map. 5907 * 5908 * Should use nodemask_t. 5909 */ 5910static int find_next_best_node(int node, nodemask_t *used_nodes) 5911{ 5912 int i, n, val, min_val, best_node = -1; 5913 5914 min_val = INT_MAX; 5915 5916 for (i = 0; i < nr_node_ids; i++) { 5917 /* Start at @node */ 5918 n = (node + i) % nr_node_ids; 5919 5920 if (!nr_cpus_node(n)) 5921 continue; 5922 5923 /* Skip already used nodes */ 5924 if (node_isset(n, *used_nodes)) 5925 continue; 5926 5927 /* Simple min distance search */ 5928 val = node_distance(node, n); 5929 5930 if (val < min_val) { 5931 min_val = val; 5932 best_node = n; 5933 } 5934 } 5935 5936 if (best_node != -1) 5937 node_set(best_node, *used_nodes); 5938 return best_node; 5939} 5940 5941/** 5942 * sched_domain_node_span - get a cpumask for a node's sched_domain 5943 * @node: node whose cpumask we're constructing 5944 * @span: resulting cpumask 5945 * 5946 * Given a node, construct a good cpumask for its sched_domain to span. It 5947 * should be one that prevents unnecessary balancing, but also spreads tasks 5948 * out optimally. 5949 */ 5950static void sched_domain_node_span(int node, struct cpumask *span) 5951{ 5952 nodemask_t used_nodes; 5953 int i; 5954 5955 cpumask_clear(span); 5956 nodes_clear(used_nodes); 5957 5958 cpumask_or(span, span, cpumask_of_node(node)); 5959 node_set(node, used_nodes); 5960 5961 for (i = 1; i < SD_NODES_PER_DOMAIN; i++) { 5962 int next_node = find_next_best_node(node, &used_nodes); 5963 if (next_node < 0) 5964 break; 5965 cpumask_or(span, span, cpumask_of_node(next_node)); 5966 } 5967} 5968 5969static const struct cpumask *cpu_node_mask(int cpu) 5970{ 5971 lockdep_assert_held(&sched_domains_mutex); 5972 5973 sched_domain_node_span(cpu_to_node(cpu), sched_domains_tmpmask); 5974 5975 return sched_domains_tmpmask; 5976} 5977 5978static const struct cpumask *cpu_allnodes_mask(int cpu) 5979{ 5980 return cpu_possible_mask; 5981} 5982#endif /* CONFIG_NUMA */ 5983 5984static const struct cpumask *cpu_cpu_mask(int cpu) 5985{ 5986 return cpumask_of_node(cpu_to_node(cpu)); 5987} 5988 5989int sched_smt_power_savings = 0, sched_mc_power_savings = 0; 5990 5991struct sd_data { 5992 struct sched_domain **__percpu sd; 5993 struct sched_group **__percpu sg; 5994 struct sched_group_power **__percpu sgp; 5995}; 5996 5997struct s_data { 5998 struct sched_domain ** __percpu sd; 5999 struct root_domain *rd; 6000}; 6001 6002enum s_alloc { 6003 sa_rootdomain, 6004 sa_sd, 6005 sa_sd_storage, 6006 sa_none, 6007}; 6008 6009struct sched_domain_topology_level; 6010 6011typedef struct sched_domain *(*sched_domain_init_f)(struct sched_domain_topology_level *tl, int cpu); 6012typedef const struct cpumask *(*sched_domain_mask_f)(int cpu); 6013 6014#define SDTL_OVERLAP 0x01 6015 6016struct sched_domain_topology_level { 6017 sched_domain_init_f init; 6018 sched_domain_mask_f mask; 6019 int flags; 6020 struct sd_data data; 6021}; 6022 6023static int 6024build_overlap_sched_groups(struct sched_domain *sd, int cpu) 6025{ 6026 struct sched_group *first = NULL, *last = NULL, *groups = NULL, *sg; 6027 const struct cpumask *span = sched_domain_span(sd); 6028 struct cpumask *covered = sched_domains_tmpmask; 6029 struct sd_data *sdd = sd->private; 6030 struct sched_domain *child; 6031 int i; 6032 6033 cpumask_clear(covered); 6034 6035 for_each_cpu(i, span) { 6036 struct cpumask *sg_span; 6037 6038 if (cpumask_test_cpu(i, covered)) 6039 continue; 6040 6041 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), 6042 GFP_KERNEL, cpu_to_node(cpu)); 6043 6044 if (!sg) 6045 goto fail; 6046 6047 sg_span = sched_group_cpus(sg); 6048 6049 child = *per_cpu_ptr(sdd->sd, i); 6050 if (child->child) { 6051 child = child->child; 6052 cpumask_copy(sg_span, sched_domain_span(child)); 6053 } else 6054 cpumask_set_cpu(i, sg_span); 6055 6056 cpumask_or(covered, covered, sg_span); 6057 6058 sg->sgp = *per_cpu_ptr(sdd->sgp, cpumask_first(sg_span)); 6059 atomic_inc(&sg->sgp->ref); 6060 6061 if (cpumask_test_cpu(cpu, sg_span)) 6062 groups = sg; 6063 6064 if (!first) 6065 first = sg; 6066 if (last) 6067 last->next = sg; 6068 last = sg; 6069 last->next = first; 6070 } 6071 sd->groups = groups; 6072 6073 return 0; 6074 6075fail: 6076 free_sched_groups(first, 0); 6077 6078 return -ENOMEM; 6079} 6080 6081static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg) 6082{ 6083 struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu); 6084 struct sched_domain *child = sd->child; 6085 6086 if (child) 6087 cpu = cpumask_first(sched_domain_span(child)); 6088 6089 if (sg) { 6090 *sg = *per_cpu_ptr(sdd->sg, cpu); 6091 (*sg)->sgp = *per_cpu_ptr(sdd->sgp, cpu); 6092 atomic_set(&(*sg)->sgp->ref, 1); /* for claim_allocations */ 6093 } 6094 6095 return cpu; 6096} 6097 6098/* 6099 * build_sched_groups will build a circular linked list of the groups 6100 * covered by the given span, and will set each group's ->cpumask correctly, 6101 * and ->cpu_power to 0. 6102 * 6103 * Assumes the sched_domain tree is fully constructed 6104 */ 6105static int 6106build_sched_groups(struct sched_domain *sd, int cpu) 6107{ 6108 struct sched_group *first = NULL, *last = NULL; 6109 struct sd_data *sdd = sd->private; 6110 const struct cpumask *span = sched_domain_span(sd); 6111 struct cpumask *covered; 6112 int i; 6113 6114 get_group(cpu, sdd, &sd->groups); 6115 atomic_inc(&sd->groups->ref); 6116 6117 if (cpu != cpumask_first(sched_domain_span(sd))) 6118 return 0; 6119 6120 lockdep_assert_held(&sched_domains_mutex); 6121 covered = sched_domains_tmpmask; 6122 6123 cpumask_clear(covered); 6124 6125 for_each_cpu(i, span) { 6126 struct sched_group *sg; 6127 int group = get_group(i, sdd, &sg); 6128 int j; 6129 6130 if (cpumask_test_cpu(i, covered)) 6131 continue; 6132 6133 cpumask_clear(sched_group_cpus(sg)); 6134 sg->sgp->power = 0; 6135 6136 for_each_cpu(j, span) { 6137 if (get_group(j, sdd, NULL) != group) 6138 continue; 6139 6140 cpumask_set_cpu(j, covered); 6141 cpumask_set_cpu(j, sched_group_cpus(sg)); 6142 } 6143 6144 if (!first) 6145 first = sg; 6146 if (last) 6147 last->next = sg; 6148 last = sg; 6149 } 6150 last->next = first; 6151 6152 return 0; 6153} 6154 6155/* 6156 * Initialize sched groups cpu_power. 6157 * 6158 * cpu_power indicates the capacity of sched group, which is used while 6159 * distributing the load between different sched groups in a sched domain. 6160 * Typically cpu_power for all the groups in a sched domain will be same unless 6161 * there are asymmetries in the topology. If there are asymmetries, group 6162 * having more cpu_power will pickup more load compared to the group having 6163 * less cpu_power. 6164 */ 6165static void init_sched_groups_power(int cpu, struct sched_domain *sd) 6166{ 6167 struct sched_group *sg = sd->groups; 6168 6169 WARN_ON(!sd || !sg); 6170 6171 do { 6172 sg->group_weight = cpumask_weight(sched_group_cpus(sg)); 6173 sg = sg->next; 6174 } while (sg != sd->groups); 6175 6176 if (cpu != group_first_cpu(sg)) 6177 return; 6178 6179 update_group_power(sd, cpu); 6180 atomic_set(&sg->sgp->nr_busy_cpus, sg->group_weight); 6181} 6182 6183int __weak arch_sd_sibling_asym_packing(void) 6184{ 6185 return 0*SD_ASYM_PACKING; 6186} 6187 6188/* 6189 * Initializers for schedule domains 6190 * Non-inlined to reduce accumulated stack pressure in build_sched_domains() 6191 */ 6192 6193#ifdef CONFIG_SCHED_DEBUG 6194# define SD_INIT_NAME(sd, type) sd->name = #type 6195#else 6196# define SD_INIT_NAME(sd, type) do { } while (0) 6197#endif 6198 6199#define SD_INIT_FUNC(type) \ 6200static noinline struct sched_domain * \ 6201sd_init_##type(struct sched_domain_topology_level *tl, int cpu) \ 6202{ \ 6203 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); \ 6204 *sd = SD_##type##_INIT; \ 6205 SD_INIT_NAME(sd, type); \ 6206 sd->private = &tl->data; \ 6207 return sd; \ 6208} 6209 6210SD_INIT_FUNC(CPU) 6211#ifdef CONFIG_NUMA 6212 SD_INIT_FUNC(ALLNODES) 6213 SD_INIT_FUNC(NODE) 6214#endif 6215#ifdef CONFIG_SCHED_SMT 6216 SD_INIT_FUNC(SIBLING) 6217#endif 6218#ifdef CONFIG_SCHED_MC 6219 SD_INIT_FUNC(MC) 6220#endif 6221#ifdef CONFIG_SCHED_BOOK 6222 SD_INIT_FUNC(BOOK) 6223#endif 6224 6225static int default_relax_domain_level = -1; 6226int sched_domain_level_max; 6227 6228static int __init setup_relax_domain_level(char *str) 6229{ 6230 unsigned long val; 6231 6232 val = simple_strtoul(str, NULL, 0); 6233 if (val < sched_domain_level_max) 6234 default_relax_domain_level = val; 6235 6236 return 1; 6237} 6238__setup("relax_domain_level=", setup_relax_domain_level); 6239 6240static void set_domain_attribute(struct sched_domain *sd, 6241 struct sched_domain_attr *attr) 6242{ 6243 int request; 6244 6245 if (!attr || attr->relax_domain_level < 0) { 6246 if (default_relax_domain_level < 0) 6247 return; 6248 else 6249 request = default_relax_domain_level; 6250 } else 6251 request = attr->relax_domain_level; 6252 if (request < sd->level) { 6253 /* turn off idle balance on this domain */ 6254 sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); 6255 } else { 6256 /* turn on idle balance on this domain */ 6257 sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); 6258 } 6259} 6260 6261static void __sdt_free(const struct cpumask *cpu_map); 6262static int __sdt_alloc(const struct cpumask *cpu_map); 6263 6264static void __free_domain_allocs(struct s_data *d, enum s_alloc what, 6265 const struct cpumask *cpu_map) 6266{ 6267 switch (what) { 6268 case sa_rootdomain: 6269 if (!atomic_read(&d->rd->refcount)) 6270 free_rootdomain(&d->rd->rcu); /* fall through */ 6271 case sa_sd: 6272 free_percpu(d->sd); /* fall through */ 6273 case sa_sd_storage: 6274 __sdt_free(cpu_map); /* fall through */ 6275 case sa_none: 6276 break; 6277 } 6278} 6279 6280static enum s_alloc __visit_domain_allocation_hell(struct s_data *d, 6281 const struct cpumask *cpu_map) 6282{ 6283 memset(d, 0, sizeof(*d)); 6284 6285 if (__sdt_alloc(cpu_map)) 6286 return sa_sd_storage; 6287 d->sd = alloc_percpu(struct sched_domain *); 6288 if (!d->sd) 6289 return sa_sd_storage; 6290 d->rd = alloc_rootdomain(); 6291 if (!d->rd) 6292 return sa_sd; 6293 return sa_rootdomain; 6294} 6295 6296/* 6297 * NULL the sd_data elements we've used to build the sched_domain and 6298 * sched_group structure so that the subsequent __free_domain_allocs() 6299 * will not free the data we're using. 6300 */ 6301static void claim_allocations(int cpu, struct sched_domain *sd) 6302{ 6303 struct sd_data *sdd = sd->private; 6304 6305 WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd); 6306 *per_cpu_ptr(sdd->sd, cpu) = NULL; 6307 6308 if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref)) 6309 *per_cpu_ptr(sdd->sg, cpu) = NULL; 6310 6311 if (atomic_read(&(*per_cpu_ptr(sdd->sgp, cpu))->ref)) 6312 *per_cpu_ptr(sdd->sgp, cpu) = NULL; 6313} 6314 6315#ifdef CONFIG_SCHED_SMT 6316static const struct cpumask *cpu_smt_mask(int cpu) 6317{ 6318 return topology_thread_cpumask(cpu); 6319} 6320#endif 6321 6322/* 6323 * Topology list, bottom-up. 6324 */ 6325static struct sched_domain_topology_level default_topology[] = { 6326#ifdef CONFIG_SCHED_SMT 6327 { sd_init_SIBLING, cpu_smt_mask, }, 6328#endif 6329#ifdef CONFIG_SCHED_MC 6330 { sd_init_MC, cpu_coregroup_mask, }, 6331#endif 6332#ifdef CONFIG_SCHED_BOOK 6333 { sd_init_BOOK, cpu_book_mask, }, 6334#endif 6335 { sd_init_CPU, cpu_cpu_mask, }, 6336#ifdef CONFIG_NUMA 6337 { sd_init_NODE, cpu_node_mask, SDTL_OVERLAP, }, 6338 { sd_init_ALLNODES, cpu_allnodes_mask, }, 6339#endif 6340 { NULL, }, 6341}; 6342 6343static struct sched_domain_topology_level *sched_domain_topology = default_topology; 6344 6345static int __sdt_alloc(const struct cpumask *cpu_map) 6346{ 6347 struct sched_domain_topology_level *tl; 6348 int j; 6349 6350 for (tl = sched_domain_topology; tl->init; tl++) { 6351 struct sd_data *sdd = &tl->data; 6352 6353 sdd->sd = alloc_percpu(struct sched_domain *); 6354 if (!sdd->sd) 6355 return -ENOMEM; 6356 6357 sdd->sg = alloc_percpu(struct sched_group *); 6358 if (!sdd->sg) 6359 return -ENOMEM; 6360 6361 sdd->sgp = alloc_percpu(struct sched_group_power *); 6362 if (!sdd->sgp) 6363 return -ENOMEM; 6364 6365 for_each_cpu(j, cpu_map) { 6366 struct sched_domain *sd; 6367 struct sched_group *sg; 6368 struct sched_group_power *sgp; 6369 6370 sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(), 6371 GFP_KERNEL, cpu_to_node(j)); 6372 if (!sd) 6373 return -ENOMEM; 6374 6375 *per_cpu_ptr(sdd->sd, j) = sd; 6376 6377 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), 6378 GFP_KERNEL, cpu_to_node(j)); 6379 if (!sg) 6380 return -ENOMEM; 6381 6382 *per_cpu_ptr(sdd->sg, j) = sg; 6383 6384 sgp = kzalloc_node(sizeof(struct sched_group_power), 6385 GFP_KERNEL, cpu_to_node(j)); 6386 if (!sgp) 6387 return -ENOMEM; 6388 6389 *per_cpu_ptr(sdd->sgp, j) = sgp; 6390 } 6391 } 6392 6393 return 0; 6394} 6395 6396static void __sdt_free(const struct cpumask *cpu_map) 6397{ 6398 struct sched_domain_topology_level *tl; 6399 int j; 6400 6401 for (tl = sched_domain_topology; tl->init; tl++) { 6402 struct sd_data *sdd = &tl->data; 6403 6404 for_each_cpu(j, cpu_map) { 6405 struct sched_domain *sd = *per_cpu_ptr(sdd->sd, j); 6406 if (sd && (sd->flags & SD_OVERLAP)) 6407 free_sched_groups(sd->groups, 0); 6408 kfree(*per_cpu_ptr(sdd->sd, j)); 6409 kfree(*per_cpu_ptr(sdd->sg, j)); 6410 kfree(*per_cpu_ptr(sdd->sgp, j)); 6411 } 6412 free_percpu(sdd->sd); 6413 free_percpu(sdd->sg); 6414 free_percpu(sdd->sgp); 6415 } 6416} 6417 6418struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl, 6419 struct s_data *d, const struct cpumask *cpu_map, 6420 struct sched_domain_attr *attr, struct sched_domain *child, 6421 int cpu) 6422{ 6423 struct sched_domain *sd = tl->init(tl, cpu); 6424 if (!sd) 6425 return child; 6426 6427 set_domain_attribute(sd, attr); 6428 cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu)); 6429 if (child) { 6430 sd->level = child->level + 1; 6431 sched_domain_level_max = max(sched_domain_level_max, sd->level); 6432 child->parent = sd; 6433 } 6434 sd->child = child; 6435 6436 return sd; 6437} 6438 6439/* 6440 * Build sched domains for a given set of cpus and attach the sched domains 6441 * to the individual cpus 6442 */ 6443static int build_sched_domains(const struct cpumask *cpu_map, 6444 struct sched_domain_attr *attr) 6445{ 6446 enum s_alloc alloc_state = sa_none; 6447 struct sched_domain *sd; 6448 struct s_data d; 6449 int i, ret = -ENOMEM; 6450 6451 alloc_state = __visit_domain_allocation_hell(&d, cpu_map); 6452 if (alloc_state != sa_rootdomain) 6453 goto error; 6454 6455 /* Set up domains for cpus specified by the cpu_map. */ 6456 for_each_cpu(i, cpu_map) { 6457 struct sched_domain_topology_level *tl; 6458 6459 sd = NULL; 6460 for (tl = sched_domain_topology; tl->init; tl++) { 6461 sd = build_sched_domain(tl, &d, cpu_map, attr, sd, i); 6462 if (tl->flags & SDTL_OVERLAP || sched_feat(FORCE_SD_OVERLAP)) 6463 sd->flags |= SD_OVERLAP; 6464 if (cpumask_equal(cpu_map, sched_domain_span(sd))) 6465 break; 6466 } 6467 6468 while (sd->child) 6469 sd = sd->child; 6470 6471 *per_cpu_ptr(d.sd, i) = sd; 6472 } 6473 6474 /* Build the groups for the domains */ 6475 for_each_cpu(i, cpu_map) { 6476 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { 6477 sd->span_weight = cpumask_weight(sched_domain_span(sd)); 6478 if (sd->flags & SD_OVERLAP) { 6479 if (build_overlap_sched_groups(sd, i)) 6480 goto error; 6481 } else { 6482 if (build_sched_groups(sd, i)) 6483 goto error; 6484 } 6485 } 6486 } 6487 6488 /* Calculate CPU power for physical packages and nodes */ 6489 for (i = nr_cpumask_bits-1; i >= 0; i--) { 6490 if (!cpumask_test_cpu(i, cpu_map)) 6491 continue; 6492 6493 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { 6494 claim_allocations(i, sd); 6495 init_sched_groups_power(i, sd); 6496 } 6497 } 6498 6499 /* Attach the domains */ 6500 rcu_read_lock(); 6501 for_each_cpu(i, cpu_map) { 6502 sd = *per_cpu_ptr(d.sd, i); 6503 cpu_attach_domain(sd, d.rd, i); 6504 } 6505 rcu_read_unlock(); 6506 6507 ret = 0; 6508error: 6509 __free_domain_allocs(&d, alloc_state, cpu_map); 6510 return ret; 6511} 6512 6513static cpumask_var_t *doms_cur; /* current sched domains */ 6514static int ndoms_cur; /* number of sched domains in 'doms_cur' */ 6515static struct sched_domain_attr *dattr_cur; 6516 /* attribues of custom domains in 'doms_cur' */ 6517 6518/* 6519 * Special case: If a kmalloc of a doms_cur partition (array of 6520 * cpumask) fails, then fallback to a single sched domain, 6521 * as determined by the single cpumask fallback_doms. 6522 */ 6523static cpumask_var_t fallback_doms; 6524 6525/* 6526 * arch_update_cpu_topology lets virtualized architectures update the 6527 * cpu core maps. It is supposed to return 1 if the topology changed 6528 * or 0 if it stayed the same. 6529 */ 6530int __attribute__((weak)) arch_update_cpu_topology(void) 6531{ 6532 return 0; 6533} 6534 6535cpumask_var_t *alloc_sched_domains(unsigned int ndoms) 6536{ 6537 int i; 6538 cpumask_var_t *doms; 6539 6540 doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL); 6541 if (!doms) 6542 return NULL; 6543 for (i = 0; i < ndoms; i++) { 6544 if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) { 6545 free_sched_domains(doms, i); 6546 return NULL; 6547 } 6548 } 6549 return doms; 6550} 6551 6552void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms) 6553{ 6554 unsigned int i; 6555 for (i = 0; i < ndoms; i++) 6556 free_cpumask_var(doms[i]); 6557 kfree(doms); 6558} 6559 6560/* 6561 * Set up scheduler domains and groups. Callers must hold the hotplug lock. 6562 * For now this just excludes isolated cpus, but could be used to 6563 * exclude other special cases in the future. 6564 */ 6565static int init_sched_domains(const struct cpumask *cpu_map) 6566{ 6567 int err; 6568 6569 arch_update_cpu_topology(); 6570 ndoms_cur = 1; 6571 doms_cur = alloc_sched_domains(ndoms_cur); 6572 if (!doms_cur) 6573 doms_cur = &fallback_doms; 6574 cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map); 6575 dattr_cur = NULL; 6576 err = build_sched_domains(doms_cur[0], NULL); 6577 register_sched_domain_sysctl(); 6578 6579 return err; 6580} 6581 6582/* 6583 * Detach sched domains from a group of cpus specified in cpu_map 6584 * These cpus will now be attached to the NULL domain 6585 */ 6586static void detach_destroy_domains(const struct cpumask *cpu_map) 6587{ 6588 int i; 6589 6590 rcu_read_lock(); 6591 for_each_cpu(i, cpu_map) 6592 cpu_attach_domain(NULL, &def_root_domain, i); 6593 rcu_read_unlock(); 6594} 6595 6596/* handle null as "default" */ 6597static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur, 6598 struct sched_domain_attr *new, int idx_new) 6599{ 6600 struct sched_domain_attr tmp; 6601 6602 /* fast path */ 6603 if (!new && !cur) 6604 return 1; 6605 6606 tmp = SD_ATTR_INIT; 6607 return !memcmp(cur ? (cur + idx_cur) : &tmp, 6608 new ? (new + idx_new) : &tmp, 6609 sizeof(struct sched_domain_attr)); 6610} 6611 6612/* 6613 * Partition sched domains as specified by the 'ndoms_new' 6614 * cpumasks in the array doms_new[] of cpumasks. This compares 6615 * doms_new[] to the current sched domain partitioning, doms_cur[]. 6616 * It destroys each deleted domain and builds each new domain. 6617 * 6618 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'. 6619 * The masks don't intersect (don't overlap.) We should setup one 6620 * sched domain for each mask. CPUs not in any of the cpumasks will 6621 * not be load balanced. If the same cpumask appears both in the 6622 * current 'doms_cur' domains and in the new 'doms_new', we can leave 6623 * it as it is. 6624 * 6625 * The passed in 'doms_new' should be allocated using 6626 * alloc_sched_domains. This routine takes ownership of it and will 6627 * free_sched_domains it when done with it. If the caller failed the 6628 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1, 6629 * and partition_sched_domains() will fallback to the single partition 6630 * 'fallback_doms', it also forces the domains to be rebuilt. 6631 * 6632 * If doms_new == NULL it will be replaced with cpu_online_mask. 6633 * ndoms_new == 0 is a special case for destroying existing domains, 6634 * and it will not create the default domain. 6635 * 6636 * Call with hotplug lock held 6637 */ 6638void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[], 6639 struct sched_domain_attr *dattr_new) 6640{ 6641 int i, j, n; 6642 int new_topology; 6643 6644 mutex_lock(&sched_domains_mutex); 6645 6646 /* always unregister in case we don't destroy any domains */ 6647 unregister_sched_domain_sysctl(); 6648 6649 /* Let architecture update cpu core mappings. */ 6650 new_topology = arch_update_cpu_topology(); 6651 6652 n = doms_new ? ndoms_new : 0; 6653 6654 /* Destroy deleted domains */ 6655 for (i = 0; i < ndoms_cur; i++) { 6656 for (j = 0; j < n && !new_topology; j++) { 6657 if (cpumask_equal(doms_cur[i], doms_new[j]) 6658 && dattrs_equal(dattr_cur, i, dattr_new, j)) 6659 goto match1; 6660 } 6661 /* no match - a current sched domain not in new doms_new[] */ 6662 detach_destroy_domains(doms_cur[i]); 6663match1: 6664 ; 6665 } 6666 6667 if (doms_new == NULL) { 6668 ndoms_cur = 0; 6669 doms_new = &fallback_doms; 6670 cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map); 6671 WARN_ON_ONCE(dattr_new); 6672 } 6673 6674 /* Build new domains */ 6675 for (i = 0; i < ndoms_new; i++) { 6676 for (j = 0; j < ndoms_cur && !new_topology; j++) { 6677 if (cpumask_equal(doms_new[i], doms_cur[j]) 6678 && dattrs_equal(dattr_new, i, dattr_cur, j)) 6679 goto match2; 6680 } 6681 /* no match - add a new doms_new */ 6682 build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL); 6683match2: 6684 ; 6685 } 6686 6687 /* Remember the new sched domains */ 6688 if (doms_cur != &fallback_doms) 6689 free_sched_domains(doms_cur, ndoms_cur); 6690 kfree(dattr_cur); /* kfree(NULL) is safe */ 6691 doms_cur = doms_new; 6692 dattr_cur = dattr_new; 6693 ndoms_cur = ndoms_new; 6694 6695 register_sched_domain_sysctl(); 6696 6697 mutex_unlock(&sched_domains_mutex); 6698} 6699 6700#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) 6701static void reinit_sched_domains(void) 6702{ 6703 get_online_cpus(); 6704 6705 /* Destroy domains first to force the rebuild */ 6706 partition_sched_domains(0, NULL, NULL); 6707 6708 rebuild_sched_domains(); 6709 put_online_cpus(); 6710} 6711 6712static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt) 6713{ 6714 unsigned int level = 0; 6715 6716 if (sscanf(buf, "%u", &level) != 1) 6717 return -EINVAL; 6718 6719 /* 6720 * level is always be positive so don't check for 6721 * level < POWERSAVINGS_BALANCE_NONE which is 0 6722 * What happens on 0 or 1 byte write, 6723 * need to check for count as well? 6724 */ 6725 6726 if (level >= MAX_POWERSAVINGS_BALANCE_LEVELS) 6727 return -EINVAL; 6728 6729 if (smt) 6730 sched_smt_power_savings = level; 6731 else 6732 sched_mc_power_savings = level; 6733 6734 reinit_sched_domains(); 6735 6736 return count; 6737} 6738 6739#ifdef CONFIG_SCHED_MC 6740static ssize_t sched_mc_power_savings_show(struct device *dev, 6741 struct device_attribute *attr, 6742 char *buf) 6743{ 6744 return sprintf(buf, "%u\n", sched_mc_power_savings); 6745} 6746static ssize_t sched_mc_power_savings_store(struct device *dev, 6747 struct device_attribute *attr, 6748 const char *buf, size_t count) 6749{ 6750 return sched_power_savings_store(buf, count, 0); 6751} 6752static DEVICE_ATTR(sched_mc_power_savings, 0644, 6753 sched_mc_power_savings_show, 6754 sched_mc_power_savings_store); 6755#endif 6756 6757#ifdef CONFIG_SCHED_SMT 6758static ssize_t sched_smt_power_savings_show(struct device *dev, 6759 struct device_attribute *attr, 6760 char *buf) 6761{ 6762 return sprintf(buf, "%u\n", sched_smt_power_savings); 6763} 6764static ssize_t sched_smt_power_savings_store(struct device *dev, 6765 struct device_attribute *attr, 6766 const char *buf, size_t count) 6767{ 6768 return sched_power_savings_store(buf, count, 1); 6769} 6770static DEVICE_ATTR(sched_smt_power_savings, 0644, 6771 sched_smt_power_savings_show, 6772 sched_smt_power_savings_store); 6773#endif 6774 6775int __init sched_create_sysfs_power_savings_entries(struct device *dev) 6776{ 6777 int err = 0; 6778 6779#ifdef CONFIG_SCHED_SMT 6780 if (smt_capable()) 6781 err = device_create_file(dev, &dev_attr_sched_smt_power_savings); 6782#endif 6783#ifdef CONFIG_SCHED_MC 6784 if (!err && mc_capable()) 6785 err = device_create_file(dev, &dev_attr_sched_mc_power_savings); 6786#endif 6787 return err; 6788} 6789#endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */ 6790 6791/* 6792 * Update cpusets according to cpu_active mask. If cpusets are 6793 * disabled, cpuset_update_active_cpus() becomes a simple wrapper 6794 * around partition_sched_domains(). 6795 */ 6796static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action, 6797 void *hcpu) 6798{ 6799 switch (action & ~CPU_TASKS_FROZEN) { 6800 case CPU_ONLINE: 6801 case CPU_DOWN_FAILED: 6802 cpuset_update_active_cpus(); 6803 return NOTIFY_OK; 6804 default: 6805 return NOTIFY_DONE; 6806 } 6807} 6808 6809static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action, 6810 void *hcpu) 6811{ 6812 switch (action & ~CPU_TASKS_FROZEN) { 6813 case CPU_DOWN_PREPARE: 6814 cpuset_update_active_cpus(); 6815 return NOTIFY_OK; 6816 default: 6817 return NOTIFY_DONE; 6818 } 6819} 6820 6821void __init sched_init_smp(void) 6822{ 6823 cpumask_var_t non_isolated_cpus; 6824 6825 alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL); 6826 alloc_cpumask_var(&fallback_doms, GFP_KERNEL); 6827 6828 get_online_cpus(); 6829 mutex_lock(&sched_domains_mutex); 6830 init_sched_domains(cpu_active_mask); 6831 cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map); 6832 if (cpumask_empty(non_isolated_cpus)) 6833 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus); 6834 mutex_unlock(&sched_domains_mutex); 6835 put_online_cpus(); 6836 6837 hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE); 6838 hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE); 6839 6840 /* RT runtime code needs to handle some hotplug events */ 6841 hotcpu_notifier(update_runtime, 0); 6842 6843 init_hrtick(); 6844 6845 /* Move init over to a non-isolated CPU */ 6846 if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0) 6847 BUG(); 6848 sched_init_granularity(); 6849 free_cpumask_var(non_isolated_cpus); 6850 6851 init_sched_rt_class(); 6852} 6853#else 6854void __init sched_init_smp(void) 6855{ 6856 sched_init_granularity(); 6857} 6858#endif /* CONFIG_SMP */ 6859 6860const_debug unsigned int sysctl_timer_migration = 1; 6861 6862int in_sched_functions(unsigned long addr) 6863{ 6864 return in_lock_functions(addr) || 6865 (addr >= (unsigned long)__sched_text_start 6866 && addr < (unsigned long)__sched_text_end); 6867} 6868 6869#ifdef CONFIG_CGROUP_SCHED 6870struct task_group root_task_group; 6871#endif 6872 6873DECLARE_PER_CPU(cpumask_var_t, load_balance_tmpmask); 6874 6875void __init sched_init(void) 6876{ 6877 int i, j; 6878 unsigned long alloc_size = 0, ptr; 6879 6880#ifdef CONFIG_FAIR_GROUP_SCHED 6881 alloc_size += 2 * nr_cpu_ids * sizeof(void **); 6882#endif 6883#ifdef CONFIG_RT_GROUP_SCHED 6884 alloc_size += 2 * nr_cpu_ids * sizeof(void **); 6885#endif 6886#ifdef CONFIG_CPUMASK_OFFSTACK 6887 alloc_size += num_possible_cpus() * cpumask_size(); 6888#endif 6889 if (alloc_size) { 6890 ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT); 6891 6892#ifdef CONFIG_FAIR_GROUP_SCHED 6893 root_task_group.se = (struct sched_entity **)ptr; 6894 ptr += nr_cpu_ids * sizeof(void **); 6895 6896 root_task_group.cfs_rq = (struct cfs_rq **)ptr; 6897 ptr += nr_cpu_ids * sizeof(void **); 6898 6899#endif /* CONFIG_FAIR_GROUP_SCHED */ 6900#ifdef CONFIG_RT_GROUP_SCHED 6901 root_task_group.rt_se = (struct sched_rt_entity **)ptr; 6902 ptr += nr_cpu_ids * sizeof(void **); 6903 6904 root_task_group.rt_rq = (struct rt_rq **)ptr; 6905 ptr += nr_cpu_ids * sizeof(void **); 6906 6907#endif /* CONFIG_RT_GROUP_SCHED */ 6908#ifdef CONFIG_CPUMASK_OFFSTACK 6909 for_each_possible_cpu(i) { 6910 per_cpu(load_balance_tmpmask, i) = (void *)ptr; 6911 ptr += cpumask_size(); 6912 } 6913#endif /* CONFIG_CPUMASK_OFFSTACK */ 6914 } 6915 6916#ifdef CONFIG_SMP 6917 init_defrootdomain(); 6918#endif 6919 6920 init_rt_bandwidth(&def_rt_bandwidth, 6921 global_rt_period(), global_rt_runtime()); 6922 6923#ifdef CONFIG_RT_GROUP_SCHED 6924 init_rt_bandwidth(&root_task_group.rt_bandwidth, 6925 global_rt_period(), global_rt_runtime()); 6926#endif /* CONFIG_RT_GROUP_SCHED */ 6927 6928#ifdef CONFIG_CGROUP_SCHED 6929 list_add(&root_task_group.list, &task_groups); 6930 INIT_LIST_HEAD(&root_task_group.children); 6931 INIT_LIST_HEAD(&root_task_group.siblings); 6932 autogroup_init(&init_task); 6933 6934#endif /* CONFIG_CGROUP_SCHED */ 6935 6936#ifdef CONFIG_CGROUP_CPUACCT 6937 root_cpuacct.cpustat = &kernel_cpustat; 6938 root_cpuacct.cpuusage = alloc_percpu(u64); 6939 /* Too early, not expected to fail */ 6940 BUG_ON(!root_cpuacct.cpuusage); 6941#endif 6942 for_each_possible_cpu(i) { 6943 struct rq *rq; 6944 6945 rq = cpu_rq(i); 6946 raw_spin_lock_init(&rq->lock); 6947 rq->nr_running = 0; 6948 rq->calc_load_active = 0; 6949 rq->calc_load_update = jiffies + LOAD_FREQ; 6950 init_cfs_rq(&rq->cfs); 6951 init_rt_rq(&rq->rt, rq); 6952#ifdef CONFIG_FAIR_GROUP_SCHED 6953 root_task_group.shares = ROOT_TASK_GROUP_LOAD; 6954 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list); 6955 /* 6956 * How much cpu bandwidth does root_task_group get? 6957 * 6958 * In case of task-groups formed thr' the cgroup filesystem, it 6959 * gets 100% of the cpu resources in the system. This overall 6960 * system cpu resource is divided among the tasks of 6961 * root_task_group and its child task-groups in a fair manner, 6962 * based on each entity's (task or task-group's) weight 6963 * (se->load.weight). 6964 * 6965 * In other words, if root_task_group has 10 tasks of weight 6966 * 1024) and two child groups A0 and A1 (of weight 1024 each), 6967 * then A0's share of the cpu resource is: 6968 * 6969 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33% 6970 * 6971 * We achieve this by letting root_task_group's tasks sit 6972 * directly in rq->cfs (i.e root_task_group->se[] = NULL). 6973 */ 6974 init_cfs_bandwidth(&root_task_group.cfs_bandwidth); 6975 init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL); 6976#endif /* CONFIG_FAIR_GROUP_SCHED */ 6977 6978 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime; 6979#ifdef CONFIG_RT_GROUP_SCHED 6980 INIT_LIST_HEAD(&rq->leaf_rt_rq_list); 6981 init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL); 6982#endif 6983 6984 for (j = 0; j < CPU_LOAD_IDX_MAX; j++) 6985 rq->cpu_load[j] = 0; 6986 6987 rq->last_load_update_tick = jiffies; 6988 6989#ifdef CONFIG_SMP 6990 rq->sd = NULL; 6991 rq->rd = NULL; 6992 rq->cpu_power = SCHED_POWER_SCALE; 6993 rq->post_schedule = 0; 6994 rq->active_balance = 0; 6995 rq->next_balance = jiffies; 6996 rq->push_cpu = 0; 6997 rq->cpu = i; 6998 rq->online = 0; 6999 rq->idle_stamp = 0; 7000 rq->avg_idle = 2*sysctl_sched_migration_cost; 7001 7002 INIT_LIST_HEAD(&rq->cfs_tasks); 7003 7004 rq_attach_root(rq, &def_root_domain); 7005#ifdef CONFIG_NO_HZ 7006 rq->nohz_flags = 0; 7007#endif 7008#endif 7009 init_rq_hrtick(rq); 7010 atomic_set(&rq->nr_iowait, 0); 7011 } 7012 7013 set_load_weight(&init_task); 7014 7015#ifdef CONFIG_PREEMPT_NOTIFIERS 7016 INIT_HLIST_HEAD(&init_task.preempt_notifiers); 7017#endif 7018 7019#ifdef CONFIG_RT_MUTEXES 7020 plist_head_init(&init_task.pi_waiters); 7021#endif 7022 7023 /* 7024 * The boot idle thread does lazy MMU switching as well: 7025 */ 7026 atomic_inc(&init_mm.mm_count); 7027 enter_lazy_tlb(&init_mm, current); 7028 7029 /* 7030 * Make us the idle thread. Technically, schedule() should not be 7031 * called from this thread, however somewhere below it might be, 7032 * but because we are the idle thread, we just pick up running again 7033 * when this runqueue becomes "idle". 7034 */ 7035 init_idle(current, smp_processor_id()); 7036 7037 calc_load_update = jiffies + LOAD_FREQ; 7038 7039 /* 7040 * During early bootup we pretend to be a normal task: 7041 */ 7042 current->sched_class = &fair_sched_class; 7043 7044#ifdef CONFIG_SMP 7045 zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT); 7046 /* May be allocated at isolcpus cmdline parse time */ 7047 if (cpu_isolated_map == NULL) 7048 zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT); 7049#endif 7050 init_sched_fair_class(); 7051 7052 scheduler_running = 1; 7053} 7054 7055#ifdef CONFIG_DEBUG_ATOMIC_SLEEP 7056static inline int preempt_count_equals(int preempt_offset) 7057{ 7058 int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth(); 7059 7060 return (nested == preempt_offset); 7061} 7062 7063void __might_sleep(const char *file, int line, int preempt_offset) 7064{ 7065 static unsigned long prev_jiffy; /* ratelimiting */ 7066 7067 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */ 7068 if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) || 7069 system_state != SYSTEM_RUNNING || oops_in_progress) 7070 return; 7071 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) 7072 return; 7073 prev_jiffy = jiffies; 7074 7075 printk(KERN_ERR 7076 "BUG: sleeping function called from invalid context at %s:%d\n", 7077 file, line); 7078 printk(KERN_ERR 7079 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n", 7080 in_atomic(), irqs_disabled(), 7081 current->pid, current->comm); 7082 7083 debug_show_held_locks(current); 7084 if (irqs_disabled()) 7085 print_irqtrace_events(current); 7086 dump_stack(); 7087} 7088EXPORT_SYMBOL(__might_sleep); 7089#endif 7090 7091#ifdef CONFIG_MAGIC_SYSRQ 7092static void normalize_task(struct rq *rq, struct task_struct *p) 7093{ 7094 const struct sched_class *prev_class = p->sched_class; 7095 int old_prio = p->prio; 7096 int on_rq; 7097 7098 on_rq = p->on_rq; 7099 if (on_rq) 7100 dequeue_task(rq, p, 0); 7101 __setscheduler(rq, p, SCHED_NORMAL, 0); 7102 if (on_rq) { 7103 enqueue_task(rq, p, 0); 7104 resched_task(rq->curr); 7105 } 7106 7107 check_class_changed(rq, p, prev_class, old_prio); 7108} 7109 7110void normalize_rt_tasks(void) 7111{ 7112 struct task_struct *g, *p; 7113 unsigned long flags; 7114 struct rq *rq; 7115 7116 read_lock_irqsave(&tasklist_lock, flags); 7117 do_each_thread(g, p) { 7118 /* 7119 * Only normalize user tasks: 7120 */ 7121 if (!p->mm) 7122 continue; 7123 7124 p->se.exec_start = 0; 7125#ifdef CONFIG_SCHEDSTATS 7126 p->se.statistics.wait_start = 0; 7127 p->se.statistics.sleep_start = 0; 7128 p->se.statistics.block_start = 0; 7129#endif 7130 7131 if (!rt_task(p)) { 7132 /* 7133 * Renice negative nice level userspace 7134 * tasks back to 0: 7135 */ 7136 if (TASK_NICE(p) < 0 && p->mm) 7137 set_user_nice(p, 0); 7138 continue; 7139 } 7140 7141 raw_spin_lock(&p->pi_lock); 7142 rq = __task_rq_lock(p); 7143 7144 normalize_task(rq, p); 7145 7146 __task_rq_unlock(rq); 7147 raw_spin_unlock(&p->pi_lock); 7148 } while_each_thread(g, p); 7149 7150 read_unlock_irqrestore(&tasklist_lock, flags); 7151} 7152 7153#endif /* CONFIG_MAGIC_SYSRQ */ 7154 7155#if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) 7156/* 7157 * These functions are only useful for the IA64 MCA handling, or kdb. 7158 * 7159 * They can only be called when the whole system has been 7160 * stopped - every CPU needs to be quiescent, and no scheduling 7161 * activity can take place. Using them for anything else would 7162 * be a serious bug, and as a result, they aren't even visible 7163 * under any other configuration. 7164 */ 7165 7166/** 7167 * curr_task - return the current task for a given cpu. 7168 * @cpu: the processor in question. 7169 * 7170 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! 7171 */ 7172struct task_struct *curr_task(int cpu) 7173{ 7174 return cpu_curr(cpu); 7175} 7176 7177#endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */ 7178 7179#ifdef CONFIG_IA64 7180/** 7181 * set_curr_task - set the current task for a given cpu. 7182 * @cpu: the processor in question. 7183 * @p: the task pointer to set. 7184 * 7185 * Description: This function must only be used when non-maskable interrupts 7186 * are serviced on a separate stack. It allows the architecture to switch the 7187 * notion of the current task on a cpu in a non-blocking manner. This function 7188 * must be called with all CPU's synchronized, and interrupts disabled, the 7189 * and caller must save the original value of the current task (see 7190 * curr_task() above) and restore that value before reenabling interrupts and 7191 * re-starting the system. 7192 * 7193 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! 7194 */ 7195void set_curr_task(int cpu, struct task_struct *p) 7196{ 7197 cpu_curr(cpu) = p; 7198} 7199 7200#endif 7201 7202#ifdef CONFIG_CGROUP_SCHED 7203/* task_group_lock serializes the addition/removal of task groups */ 7204static DEFINE_SPINLOCK(task_group_lock); 7205 7206static void free_sched_group(struct task_group *tg) 7207{ 7208 free_fair_sched_group(tg); 7209 free_rt_sched_group(tg); 7210 autogroup_free(tg); 7211 kfree(tg); 7212} 7213 7214/* allocate runqueue etc for a new task group */ 7215struct task_group *sched_create_group(struct task_group *parent) 7216{ 7217 struct task_group *tg; 7218 unsigned long flags; 7219 7220 tg = kzalloc(sizeof(*tg), GFP_KERNEL); 7221 if (!tg) 7222 return ERR_PTR(-ENOMEM); 7223 7224 if (!alloc_fair_sched_group(tg, parent)) 7225 goto err; 7226 7227 if (!alloc_rt_sched_group(tg, parent)) 7228 goto err; 7229 7230 spin_lock_irqsave(&task_group_lock, flags); 7231 list_add_rcu(&tg->list, &task_groups); 7232 7233 WARN_ON(!parent); /* root should already exist */ 7234 7235 tg->parent = parent; 7236 INIT_LIST_HEAD(&tg->children); 7237 list_add_rcu(&tg->siblings, &parent->children); 7238 spin_unlock_irqrestore(&task_group_lock, flags); 7239 7240 return tg; 7241 7242err: 7243 free_sched_group(tg); 7244 return ERR_PTR(-ENOMEM); 7245} 7246 7247/* rcu callback to free various structures associated with a task group */ 7248static void free_sched_group_rcu(struct rcu_head *rhp) 7249{ 7250 /* now it should be safe to free those cfs_rqs */ 7251 free_sched_group(container_of(rhp, struct task_group, rcu)); 7252} 7253 7254/* Destroy runqueue etc associated with a task group */ 7255void sched_destroy_group(struct task_group *tg) 7256{ 7257 unsigned long flags; 7258 int i; 7259 7260 /* end participation in shares distribution */ 7261 for_each_possible_cpu(i) 7262 unregister_fair_sched_group(tg, i); 7263 7264 spin_lock_irqsave(&task_group_lock, flags); 7265 list_del_rcu(&tg->list); 7266 list_del_rcu(&tg->siblings); 7267 spin_unlock_irqrestore(&task_group_lock, flags); 7268 7269 /* wait for possible concurrent references to cfs_rqs complete */ 7270 call_rcu(&tg->rcu, free_sched_group_rcu); 7271} 7272 7273/* change task's runqueue when it moves between groups. 7274 * The caller of this function should have put the task in its new group 7275 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to 7276 * reflect its new group. 7277 */ 7278void sched_move_task(struct task_struct *tsk) 7279{ 7280 int on_rq, running; 7281 unsigned long flags; 7282 struct rq *rq; 7283 7284 rq = task_rq_lock(tsk, &flags); 7285 7286 running = task_current(rq, tsk); 7287 on_rq = tsk->on_rq; 7288 7289 if (on_rq) 7290 dequeue_task(rq, tsk, 0); 7291 if (unlikely(running)) 7292 tsk->sched_class->put_prev_task(rq, tsk); 7293 7294#ifdef CONFIG_FAIR_GROUP_SCHED 7295 if (tsk->sched_class->task_move_group) 7296 tsk->sched_class->task_move_group(tsk, on_rq); 7297 else 7298#endif 7299 set_task_rq(tsk, task_cpu(tsk)); 7300 7301 if (unlikely(running)) 7302 tsk->sched_class->set_curr_task(rq); 7303 if (on_rq) 7304 enqueue_task(rq, tsk, 0); 7305 7306 task_rq_unlock(rq, tsk, &flags); 7307} 7308#endif /* CONFIG_CGROUP_SCHED */ 7309 7310#if defined(CONFIG_RT_GROUP_SCHED) || defined(CONFIG_CFS_BANDWIDTH) 7311static unsigned long to_ratio(u64 period, u64 runtime) 7312{ 7313 if (runtime == RUNTIME_INF) 7314 return 1ULL << 20; 7315 7316 return div64_u64(runtime << 20, period); 7317} 7318#endif 7319 7320#ifdef CONFIG_RT_GROUP_SCHED 7321/* 7322 * Ensure that the real time constraints are schedulable. 7323 */ 7324static DEFINE_MUTEX(rt_constraints_mutex); 7325 7326/* Must be called with tasklist_lock held */ 7327static inline int tg_has_rt_tasks(struct task_group *tg) 7328{ 7329 struct task_struct *g, *p; 7330 7331 do_each_thread(g, p) { 7332 if (rt_task(p) && task_rq(p)->rt.tg == tg) 7333 return 1; 7334 } while_each_thread(g, p); 7335 7336 return 0; 7337} 7338 7339struct rt_schedulable_data { 7340 struct task_group *tg; 7341 u64 rt_period; 7342 u64 rt_runtime; 7343}; 7344 7345static int tg_rt_schedulable(struct task_group *tg, void *data) 7346{ 7347 struct rt_schedulable_data *d = data; 7348 struct task_group *child; 7349 unsigned long total, sum = 0; 7350 u64 period, runtime; 7351 7352 period = ktime_to_ns(tg->rt_bandwidth.rt_period); 7353 runtime = tg->rt_bandwidth.rt_runtime; 7354 7355 if (tg == d->tg) { 7356 period = d->rt_period; 7357 runtime = d->rt_runtime; 7358 } 7359 7360 /* 7361 * Cannot have more runtime than the period. 7362 */ 7363 if (runtime > period && runtime != RUNTIME_INF) 7364 return -EINVAL; 7365 7366 /* 7367 * Ensure we don't starve existing RT tasks. 7368 */ 7369 if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg)) 7370 return -EBUSY; 7371 7372 total = to_ratio(period, runtime); 7373 7374 /* 7375 * Nobody can have more than the global setting allows. 7376 */ 7377 if (total > to_ratio(global_rt_period(), global_rt_runtime())) 7378 return -EINVAL; 7379 7380 /* 7381 * The sum of our children's runtime should not exceed our own. 7382 */ 7383 list_for_each_entry_rcu(child, &tg->children, siblings) { 7384 period = ktime_to_ns(child->rt_bandwidth.rt_period); 7385 runtime = child->rt_bandwidth.rt_runtime; 7386 7387 if (child == d->tg) { 7388 period = d->rt_period; 7389 runtime = d->rt_runtime; 7390 } 7391 7392 sum += to_ratio(period, runtime); 7393 } 7394 7395 if (sum > total) 7396 return -EINVAL; 7397 7398 return 0; 7399} 7400 7401static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime) 7402{ 7403 int ret; 7404 7405 struct rt_schedulable_data data = { 7406 .tg = tg, 7407 .rt_period = period, 7408 .rt_runtime = runtime, 7409 }; 7410 7411 rcu_read_lock(); 7412 ret = walk_tg_tree(tg_rt_schedulable, tg_nop, &data); 7413 rcu_read_unlock(); 7414 7415 return ret; 7416} 7417 7418static int tg_set_rt_bandwidth(struct task_group *tg, 7419 u64 rt_period, u64 rt_runtime) 7420{ 7421 int i, err = 0; 7422 7423 mutex_lock(&rt_constraints_mutex); 7424 read_lock(&tasklist_lock); 7425 err = __rt_schedulable(tg, rt_period, rt_runtime); 7426 if (err) 7427 goto unlock; 7428 7429 raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock); 7430 tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period); 7431 tg->rt_bandwidth.rt_runtime = rt_runtime; 7432 7433 for_each_possible_cpu(i) { 7434 struct rt_rq *rt_rq = tg->rt_rq[i]; 7435 7436 raw_spin_lock(&rt_rq->rt_runtime_lock); 7437 rt_rq->rt_runtime = rt_runtime; 7438 raw_spin_unlock(&rt_rq->rt_runtime_lock); 7439 } 7440 raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock); 7441unlock: 7442 read_unlock(&tasklist_lock); 7443 mutex_unlock(&rt_constraints_mutex); 7444 7445 return err; 7446} 7447 7448int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us) 7449{ 7450 u64 rt_runtime, rt_period; 7451 7452 rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period); 7453 rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC; 7454 if (rt_runtime_us < 0) 7455 rt_runtime = RUNTIME_INF; 7456 7457 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); 7458} 7459 7460long sched_group_rt_runtime(struct task_group *tg) 7461{ 7462 u64 rt_runtime_us; 7463 7464 if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF) 7465 return -1; 7466 7467 rt_runtime_us = tg->rt_bandwidth.rt_runtime; 7468 do_div(rt_runtime_us, NSEC_PER_USEC); 7469 return rt_runtime_us; 7470} 7471 7472int sched_group_set_rt_period(struct task_group *tg, long rt_period_us) 7473{ 7474 u64 rt_runtime, rt_period; 7475 7476 rt_period = (u64)rt_period_us * NSEC_PER_USEC; 7477 rt_runtime = tg->rt_bandwidth.rt_runtime; 7478 7479 if (rt_period == 0) 7480 return -EINVAL; 7481 7482 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); 7483} 7484 7485long sched_group_rt_period(struct task_group *tg) 7486{ 7487 u64 rt_period_us; 7488 7489 rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period); 7490 do_div(rt_period_us, NSEC_PER_USEC); 7491 return rt_period_us; 7492} 7493 7494static int sched_rt_global_constraints(void) 7495{ 7496 u64 runtime, period; 7497 int ret = 0; 7498 7499 if (sysctl_sched_rt_period <= 0) 7500 return -EINVAL; 7501 7502 runtime = global_rt_runtime(); 7503 period = global_rt_period(); 7504 7505 /* 7506 * Sanity check on the sysctl variables. 7507 */ 7508 if (runtime > period && runtime != RUNTIME_INF) 7509 return -EINVAL; 7510 7511 mutex_lock(&rt_constraints_mutex); 7512 read_lock(&tasklist_lock); 7513 ret = __rt_schedulable(NULL, 0, 0); 7514 read_unlock(&tasklist_lock); 7515 mutex_unlock(&rt_constraints_mutex); 7516 7517 return ret; 7518} 7519 7520int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk) 7521{ 7522 /* Don't accept realtime tasks when there is no way for them to run */ 7523 if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0) 7524 return 0; 7525 7526 return 1; 7527} 7528 7529#else /* !CONFIG_RT_GROUP_SCHED */ 7530static int sched_rt_global_constraints(void) 7531{ 7532 unsigned long flags; 7533 int i; 7534 7535 if (sysctl_sched_rt_period <= 0) 7536 return -EINVAL; 7537 7538 /* 7539 * There's always some RT tasks in the root group 7540 * -- migration, kstopmachine etc.. 7541 */ 7542 if (sysctl_sched_rt_runtime == 0) 7543 return -EBUSY; 7544 7545 raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags); 7546 for_each_possible_cpu(i) { 7547 struct rt_rq *rt_rq = &cpu_rq(i)->rt; 7548 7549 raw_spin_lock(&rt_rq->rt_runtime_lock); 7550 rt_rq->rt_runtime = global_rt_runtime(); 7551 raw_spin_unlock(&rt_rq->rt_runtime_lock); 7552 } 7553 raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags); 7554 7555 return 0; 7556} 7557#endif /* CONFIG_RT_GROUP_SCHED */ 7558 7559int sched_rt_handler(struct ctl_table *table, int write, 7560 void __user *buffer, size_t *lenp, 7561 loff_t *ppos) 7562{ 7563 int ret; 7564 int old_period, old_runtime; 7565 static DEFINE_MUTEX(mutex); 7566 7567 mutex_lock(&mutex); 7568 old_period = sysctl_sched_rt_period; 7569 old_runtime = sysctl_sched_rt_runtime; 7570 7571 ret = proc_dointvec(table, write, buffer, lenp, ppos); 7572 7573 if (!ret && write) { 7574 ret = sched_rt_global_constraints(); 7575 if (ret) { 7576 sysctl_sched_rt_period = old_period; 7577 sysctl_sched_rt_runtime = old_runtime; 7578 } else { 7579 def_rt_bandwidth.rt_runtime = global_rt_runtime(); 7580 def_rt_bandwidth.rt_period = 7581 ns_to_ktime(global_rt_period()); 7582 } 7583 } 7584 mutex_unlock(&mutex); 7585 7586 return ret; 7587} 7588 7589#ifdef CONFIG_CGROUP_SCHED 7590 7591/* return corresponding task_group object of a cgroup */ 7592static inline struct task_group *cgroup_tg(struct cgroup *cgrp) 7593{ 7594 return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id), 7595 struct task_group, css); 7596} 7597 7598static struct cgroup_subsys_state *cpu_cgroup_create(struct cgroup *cgrp) 7599{ 7600 struct task_group *tg, *parent; 7601 7602 if (!cgrp->parent) { 7603 /* This is early initialization for the top cgroup */ 7604 return &root_task_group.css; 7605 } 7606 7607 parent = cgroup_tg(cgrp->parent); 7608 tg = sched_create_group(parent); 7609 if (IS_ERR(tg)) 7610 return ERR_PTR(-ENOMEM); 7611 7612 return &tg->css; 7613} 7614 7615static void cpu_cgroup_destroy(struct cgroup *cgrp) 7616{ 7617 struct task_group *tg = cgroup_tg(cgrp); 7618 7619 sched_destroy_group(tg); 7620} 7621 7622static int cpu_cgroup_can_attach(struct cgroup *cgrp, 7623 struct cgroup_taskset *tset) 7624{ 7625 struct task_struct *task; 7626 7627 cgroup_taskset_for_each(task, cgrp, tset) { 7628#ifdef CONFIG_RT_GROUP_SCHED 7629 if (!sched_rt_can_attach(cgroup_tg(cgrp), task)) 7630 return -EINVAL; 7631#else 7632 /* We don't support RT-tasks being in separate groups */ 7633 if (task->sched_class != &fair_sched_class) 7634 return -EINVAL; 7635#endif 7636 } 7637 return 0; 7638} 7639 7640static void cpu_cgroup_attach(struct cgroup *cgrp, 7641 struct cgroup_taskset *tset) 7642{ 7643 struct task_struct *task; 7644 7645 cgroup_taskset_for_each(task, cgrp, tset) 7646 sched_move_task(task); 7647} 7648 7649static void 7650cpu_cgroup_exit(struct cgroup *cgrp, struct cgroup *old_cgrp, 7651 struct task_struct *task) 7652{ 7653 /* 7654 * cgroup_exit() is called in the copy_process() failure path. 7655 * Ignore this case since the task hasn't ran yet, this avoids 7656 * trying to poke a half freed task state from generic code. 7657 */ 7658 if (!(task->flags & PF_EXITING)) 7659 return; 7660 7661 sched_move_task(task); 7662} 7663 7664#ifdef CONFIG_FAIR_GROUP_SCHED 7665static int cpu_shares_write_u64(struct cgroup *cgrp, struct cftype *cftype, 7666 u64 shareval) 7667{ 7668 return sched_group_set_shares(cgroup_tg(cgrp), scale_load(shareval)); 7669} 7670 7671static u64 cpu_shares_read_u64(struct cgroup *cgrp, struct cftype *cft) 7672{ 7673 struct task_group *tg = cgroup_tg(cgrp); 7674 7675 return (u64) scale_load_down(tg->shares); 7676} 7677 7678#ifdef CONFIG_CFS_BANDWIDTH 7679static DEFINE_MUTEX(cfs_constraints_mutex); 7680 7681const u64 max_cfs_quota_period = 1 * NSEC_PER_SEC; /* 1s */ 7682const u64 min_cfs_quota_period = 1 * NSEC_PER_MSEC; /* 1ms */ 7683 7684static int __cfs_schedulable(struct task_group *tg, u64 period, u64 runtime); 7685 7686static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota) 7687{ 7688 int i, ret = 0, runtime_enabled, runtime_was_enabled; 7689 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 7690 7691 if (tg == &root_task_group) 7692 return -EINVAL; 7693 7694 /* 7695 * Ensure we have at some amount of bandwidth every period. This is 7696 * to prevent reaching a state of large arrears when throttled via 7697 * entity_tick() resulting in prolonged exit starvation. 7698 */ 7699 if (quota < min_cfs_quota_period || period < min_cfs_quota_period) 7700 return -EINVAL; 7701 7702 /* 7703 * Likewise, bound things on the otherside by preventing insane quota 7704 * periods. This also allows us to normalize in computing quota 7705 * feasibility. 7706 */ 7707 if (period > max_cfs_quota_period) 7708 return -EINVAL; 7709 7710 mutex_lock(&cfs_constraints_mutex); 7711 ret = __cfs_schedulable(tg, period, quota); 7712 if (ret) 7713 goto out_unlock; 7714 7715 runtime_enabled = quota != RUNTIME_INF; 7716 runtime_was_enabled = cfs_b->quota != RUNTIME_INF; 7717 account_cfs_bandwidth_used(runtime_enabled, runtime_was_enabled); 7718 raw_spin_lock_irq(&cfs_b->lock); 7719 cfs_b->period = ns_to_ktime(period); 7720 cfs_b->quota = quota; 7721 7722 __refill_cfs_bandwidth_runtime(cfs_b); 7723 /* restart the period timer (if active) to handle new period expiry */ 7724 if (runtime_enabled && cfs_b->timer_active) { 7725 /* force a reprogram */ 7726 cfs_b->timer_active = 0; 7727 __start_cfs_bandwidth(cfs_b); 7728 } 7729 raw_spin_unlock_irq(&cfs_b->lock); 7730 7731 for_each_possible_cpu(i) { 7732 struct cfs_rq *cfs_rq = tg->cfs_rq[i]; 7733 struct rq *rq = cfs_rq->rq; 7734 7735 raw_spin_lock_irq(&rq->lock); 7736 cfs_rq->runtime_enabled = runtime_enabled; 7737 cfs_rq->runtime_remaining = 0; 7738 7739 if (cfs_rq->throttled) 7740 unthrottle_cfs_rq(cfs_rq); 7741 raw_spin_unlock_irq(&rq->lock); 7742 } 7743out_unlock: 7744 mutex_unlock(&cfs_constraints_mutex); 7745 7746 return ret; 7747} 7748 7749int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us) 7750{ 7751 u64 quota, period; 7752 7753 period = ktime_to_ns(tg->cfs_bandwidth.period); 7754 if (cfs_quota_us < 0) 7755 quota = RUNTIME_INF; 7756 else 7757 quota = (u64)cfs_quota_us * NSEC_PER_USEC; 7758 7759 return tg_set_cfs_bandwidth(tg, period, quota); 7760} 7761 7762long tg_get_cfs_quota(struct task_group *tg) 7763{ 7764 u64 quota_us; 7765 7766 if (tg->cfs_bandwidth.quota == RUNTIME_INF) 7767 return -1; 7768 7769 quota_us = tg->cfs_bandwidth.quota; 7770 do_div(quota_us, NSEC_PER_USEC); 7771 7772 return quota_us; 7773} 7774 7775int tg_set_cfs_period(struct task_group *tg, long cfs_period_us) 7776{ 7777 u64 quota, period; 7778 7779 period = (u64)cfs_period_us * NSEC_PER_USEC; 7780 quota = tg->cfs_bandwidth.quota; 7781 7782 return tg_set_cfs_bandwidth(tg, period, quota); 7783} 7784 7785long tg_get_cfs_period(struct task_group *tg) 7786{ 7787 u64 cfs_period_us; 7788 7789 cfs_period_us = ktime_to_ns(tg->cfs_bandwidth.period); 7790 do_div(cfs_period_us, NSEC_PER_USEC); 7791 7792 return cfs_period_us; 7793} 7794 7795static s64 cpu_cfs_quota_read_s64(struct cgroup *cgrp, struct cftype *cft) 7796{ 7797 return tg_get_cfs_quota(cgroup_tg(cgrp)); 7798} 7799 7800static int cpu_cfs_quota_write_s64(struct cgroup *cgrp, struct cftype *cftype, 7801 s64 cfs_quota_us) 7802{ 7803 return tg_set_cfs_quota(cgroup_tg(cgrp), cfs_quota_us); 7804} 7805 7806static u64 cpu_cfs_period_read_u64(struct cgroup *cgrp, struct cftype *cft) 7807{ 7808 return tg_get_cfs_period(cgroup_tg(cgrp)); 7809} 7810 7811static int cpu_cfs_period_write_u64(struct cgroup *cgrp, struct cftype *cftype, 7812 u64 cfs_period_us) 7813{ 7814 return tg_set_cfs_period(cgroup_tg(cgrp), cfs_period_us); 7815} 7816 7817struct cfs_schedulable_data { 7818 struct task_group *tg; 7819 u64 period, quota; 7820}; 7821 7822/* 7823 * normalize group quota/period to be quota/max_period 7824 * note: units are usecs 7825 */ 7826static u64 normalize_cfs_quota(struct task_group *tg, 7827 struct cfs_schedulable_data *d) 7828{ 7829 u64 quota, period; 7830 7831 if (tg == d->tg) { 7832 period = d->period; 7833 quota = d->quota; 7834 } else { 7835 period = tg_get_cfs_period(tg); 7836 quota = tg_get_cfs_quota(tg); 7837 } 7838 7839 /* note: these should typically be equivalent */ 7840 if (quota == RUNTIME_INF || quota == -1) 7841 return RUNTIME_INF; 7842 7843 return to_ratio(period, quota); 7844} 7845 7846static int tg_cfs_schedulable_down(struct task_group *tg, void *data) 7847{ 7848 struct cfs_schedulable_data *d = data; 7849 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 7850 s64 quota = 0, parent_quota = -1; 7851 7852 if (!tg->parent) { 7853 quota = RUNTIME_INF; 7854 } else { 7855 struct cfs_bandwidth *parent_b = &tg->parent->cfs_bandwidth; 7856 7857 quota = normalize_cfs_quota(tg, d); 7858 parent_quota = parent_b->hierarchal_quota; 7859 7860 /* 7861 * ensure max(child_quota) <= parent_quota, inherit when no 7862 * limit is set 7863 */ 7864 if (quota == RUNTIME_INF) 7865 quota = parent_quota; 7866 else if (parent_quota != RUNTIME_INF && quota > parent_quota) 7867 return -EINVAL; 7868 } 7869 cfs_b->hierarchal_quota = quota; 7870 7871 return 0; 7872} 7873 7874static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota) 7875{ 7876 int ret; 7877 struct cfs_schedulable_data data = { 7878 .tg = tg, 7879 .period = period, 7880 .quota = quota, 7881 }; 7882 7883 if (quota != RUNTIME_INF) { 7884 do_div(data.period, NSEC_PER_USEC); 7885 do_div(data.quota, NSEC_PER_USEC); 7886 } 7887 7888 rcu_read_lock(); 7889 ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data); 7890 rcu_read_unlock(); 7891 7892 return ret; 7893} 7894 7895static int cpu_stats_show(struct cgroup *cgrp, struct cftype *cft, 7896 struct cgroup_map_cb *cb) 7897{ 7898 struct task_group *tg = cgroup_tg(cgrp); 7899 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 7900 7901 cb->fill(cb, "nr_periods", cfs_b->nr_periods); 7902 cb->fill(cb, "nr_throttled", cfs_b->nr_throttled); 7903 cb->fill(cb, "throttled_time", cfs_b->throttled_time); 7904 7905 return 0; 7906} 7907#endif /* CONFIG_CFS_BANDWIDTH */ 7908#endif /* CONFIG_FAIR_GROUP_SCHED */ 7909 7910#ifdef CONFIG_RT_GROUP_SCHED 7911static int cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft, 7912 s64 val) 7913{ 7914 return sched_group_set_rt_runtime(cgroup_tg(cgrp), val); 7915} 7916 7917static s64 cpu_rt_runtime_read(struct cgroup *cgrp, struct cftype *cft) 7918{ 7919 return sched_group_rt_runtime(cgroup_tg(cgrp)); 7920} 7921 7922static int cpu_rt_period_write_uint(struct cgroup *cgrp, struct cftype *cftype, 7923 u64 rt_period_us) 7924{ 7925 return sched_group_set_rt_period(cgroup_tg(cgrp), rt_period_us); 7926} 7927 7928static u64 cpu_rt_period_read_uint(struct cgroup *cgrp, struct cftype *cft) 7929{ 7930 return sched_group_rt_period(cgroup_tg(cgrp)); 7931} 7932#endif /* CONFIG_RT_GROUP_SCHED */ 7933 7934static struct cftype cpu_files[] = { 7935#ifdef CONFIG_FAIR_GROUP_SCHED 7936 { 7937 .name = "shares", 7938 .read_u64 = cpu_shares_read_u64, 7939 .write_u64 = cpu_shares_write_u64, 7940 }, 7941#endif 7942#ifdef CONFIG_CFS_BANDWIDTH 7943 { 7944 .name = "cfs_quota_us", 7945 .read_s64 = cpu_cfs_quota_read_s64, 7946 .write_s64 = cpu_cfs_quota_write_s64, 7947 }, 7948 { 7949 .name = "cfs_period_us", 7950 .read_u64 = cpu_cfs_period_read_u64, 7951 .write_u64 = cpu_cfs_period_write_u64, 7952 }, 7953 { 7954 .name = "stat", 7955 .read_map = cpu_stats_show, 7956 }, 7957#endif 7958#ifdef CONFIG_RT_GROUP_SCHED 7959 { 7960 .name = "rt_runtime_us", 7961 .read_s64 = cpu_rt_runtime_read, 7962 .write_s64 = cpu_rt_runtime_write, 7963 }, 7964 { 7965 .name = "rt_period_us", 7966 .read_u64 = cpu_rt_period_read_uint, 7967 .write_u64 = cpu_rt_period_write_uint, 7968 }, 7969#endif 7970}; 7971 7972static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont) 7973{ 7974 return cgroup_add_files(cont, ss, cpu_files, ARRAY_SIZE(cpu_files)); 7975} 7976 7977struct cgroup_subsys cpu_cgroup_subsys = { 7978 .name = "cpu", 7979 .create = cpu_cgroup_create, 7980 .destroy = cpu_cgroup_destroy, 7981 .can_attach = cpu_cgroup_can_attach, 7982 .attach = cpu_cgroup_attach, 7983 .exit = cpu_cgroup_exit, 7984 .populate = cpu_cgroup_populate, 7985 .subsys_id = cpu_cgroup_subsys_id, 7986 .early_init = 1, 7987}; 7988 7989#endif /* CONFIG_CGROUP_SCHED */ 7990 7991#ifdef CONFIG_CGROUP_CPUACCT 7992 7993/* 7994 * CPU accounting code for task groups. 7995 * 7996 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh 7997 * (balbir@in.ibm.com). 7998 */ 7999 8000/* create a new cpu accounting group */ 8001static struct cgroup_subsys_state *cpuacct_create(struct cgroup *cgrp) 8002{ 8003 struct cpuacct *ca; 8004 8005 if (!cgrp->parent) 8006 return &root_cpuacct.css; 8007 8008 ca = kzalloc(sizeof(*ca), GFP_KERNEL); 8009 if (!ca) 8010 goto out; 8011 8012 ca->cpuusage = alloc_percpu(u64); 8013 if (!ca->cpuusage) 8014 goto out_free_ca; 8015 8016 ca->cpustat = alloc_percpu(struct kernel_cpustat); 8017 if (!ca->cpustat) 8018 goto out_free_cpuusage; 8019 8020 return &ca->css; 8021 8022out_free_cpuusage: 8023 free_percpu(ca->cpuusage); 8024out_free_ca: 8025 kfree(ca); 8026out: 8027 return ERR_PTR(-ENOMEM); 8028} 8029 8030/* destroy an existing cpu accounting group */ 8031static void cpuacct_destroy(struct cgroup *cgrp) 8032{ 8033 struct cpuacct *ca = cgroup_ca(cgrp); 8034 8035 free_percpu(ca->cpustat); 8036 free_percpu(ca->cpuusage); 8037 kfree(ca); 8038} 8039 8040static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu) 8041{ 8042 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); 8043 u64 data; 8044 8045#ifndef CONFIG_64BIT 8046 /* 8047 * Take rq->lock to make 64-bit read safe on 32-bit platforms. 8048 */ 8049 raw_spin_lock_irq(&cpu_rq(cpu)->lock); 8050 data = *cpuusage; 8051 raw_spin_unlock_irq(&cpu_rq(cpu)->lock); 8052#else 8053 data = *cpuusage; 8054#endif 8055 8056 return data; 8057} 8058 8059static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val) 8060{ 8061 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); 8062 8063#ifndef CONFIG_64BIT 8064 /* 8065 * Take rq->lock to make 64-bit write safe on 32-bit platforms. 8066 */ 8067 raw_spin_lock_irq(&cpu_rq(cpu)->lock); 8068 *cpuusage = val; 8069 raw_spin_unlock_irq(&cpu_rq(cpu)->lock); 8070#else 8071 *cpuusage = val; 8072#endif 8073} 8074 8075/* return total cpu usage (in nanoseconds) of a group */ 8076static u64 cpuusage_read(struct cgroup *cgrp, struct cftype *cft) 8077{ 8078 struct cpuacct *ca = cgroup_ca(cgrp); 8079 u64 totalcpuusage = 0; 8080 int i; 8081 8082 for_each_present_cpu(i) 8083 totalcpuusage += cpuacct_cpuusage_read(ca, i); 8084 8085 return totalcpuusage; 8086} 8087 8088static int cpuusage_write(struct cgroup *cgrp, struct cftype *cftype, 8089 u64 reset) 8090{ 8091 struct cpuacct *ca = cgroup_ca(cgrp); 8092 int err = 0; 8093 int i; 8094 8095 if (reset) { 8096 err = -EINVAL; 8097 goto out; 8098 } 8099 8100 for_each_present_cpu(i) 8101 cpuacct_cpuusage_write(ca, i, 0); 8102 8103out: 8104 return err; 8105} 8106 8107static int cpuacct_percpu_seq_read(struct cgroup *cgroup, struct cftype *cft, 8108 struct seq_file *m) 8109{ 8110 struct cpuacct *ca = cgroup_ca(cgroup); 8111 u64 percpu; 8112 int i; 8113 8114 for_each_present_cpu(i) { 8115 percpu = cpuacct_cpuusage_read(ca, i); 8116 seq_printf(m, "%llu ", (unsigned long long) percpu); 8117 } 8118 seq_printf(m, "\n"); 8119 return 0; 8120} 8121 8122static const char *cpuacct_stat_desc[] = { 8123 [CPUACCT_STAT_USER] = "user", 8124 [CPUACCT_STAT_SYSTEM] = "system", 8125}; 8126 8127static int cpuacct_stats_show(struct cgroup *cgrp, struct cftype *cft, 8128 struct cgroup_map_cb *cb) 8129{ 8130 struct cpuacct *ca = cgroup_ca(cgrp); 8131 int cpu; 8132 s64 val = 0; 8133 8134 for_each_online_cpu(cpu) { 8135 struct kernel_cpustat *kcpustat = per_cpu_ptr(ca->cpustat, cpu); 8136 val += kcpustat->cpustat[CPUTIME_USER]; 8137 val += kcpustat->cpustat[CPUTIME_NICE]; 8138 } 8139 val = cputime64_to_clock_t(val); 8140 cb->fill(cb, cpuacct_stat_desc[CPUACCT_STAT_USER], val); 8141 8142 val = 0; 8143 for_each_online_cpu(cpu) { 8144 struct kernel_cpustat *kcpustat = per_cpu_ptr(ca->cpustat, cpu); 8145 val += kcpustat->cpustat[CPUTIME_SYSTEM]; 8146 val += kcpustat->cpustat[CPUTIME_IRQ]; 8147 val += kcpustat->cpustat[CPUTIME_SOFTIRQ]; 8148 } 8149 8150 val = cputime64_to_clock_t(val); 8151 cb->fill(cb, cpuacct_stat_desc[CPUACCT_STAT_SYSTEM], val); 8152 8153 return 0; 8154} 8155 8156static struct cftype files[] = { 8157 { 8158 .name = "usage", 8159 .read_u64 = cpuusage_read, 8160 .write_u64 = cpuusage_write, 8161 }, 8162 { 8163 .name = "usage_percpu", 8164 .read_seq_string = cpuacct_percpu_seq_read, 8165 }, 8166 { 8167 .name = "stat", 8168 .read_map = cpuacct_stats_show, 8169 }, 8170}; 8171 8172static int cpuacct_populate(struct cgroup_subsys *ss, struct cgroup *cgrp) 8173{ 8174 return cgroup_add_files(cgrp, ss, files, ARRAY_SIZE(files)); 8175} 8176 8177/* 8178 * charge this task's execution time to its accounting group. 8179 * 8180 * called with rq->lock held. 8181 */ 8182void cpuacct_charge(struct task_struct *tsk, u64 cputime) 8183{ 8184 struct cpuacct *ca; 8185 int cpu; 8186 8187 if (unlikely(!cpuacct_subsys.active)) 8188 return; 8189 8190 cpu = task_cpu(tsk); 8191 8192 rcu_read_lock(); 8193 8194 ca = task_ca(tsk); 8195 8196 for (; ca; ca = parent_ca(ca)) { 8197 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); 8198 *cpuusage += cputime; 8199 } 8200 8201 rcu_read_unlock(); 8202} 8203 8204struct cgroup_subsys cpuacct_subsys = { 8205 .name = "cpuacct", 8206 .create = cpuacct_create, 8207 .destroy = cpuacct_destroy, 8208 .populate = cpuacct_populate, 8209 .subsys_id = cpuacct_subsys_id, 8210}; 8211#endif /* CONFIG_CGROUP_CPUACCT */ 8212