core.c revision 4ca9b72b71f10147bd21969c1805f5b2c4ca7b7b
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 75#include <asm/tlb.h> 76#include <asm/irq_regs.h> 77#ifdef CONFIG_PARAVIRT 78#include <asm/paravirt.h> 79#endif 80 81#include "sched.h" 82#include "../workqueue_sched.h" 83 84#define CREATE_TRACE_POINTS 85#include <trace/events/sched.h> 86 87void start_bandwidth_timer(struct hrtimer *period_timer, ktime_t period) 88{ 89 unsigned long delta; 90 ktime_t soft, hard, now; 91 92 for (;;) { 93 if (hrtimer_active(period_timer)) 94 break; 95 96 now = hrtimer_cb_get_time(period_timer); 97 hrtimer_forward(period_timer, now, period); 98 99 soft = hrtimer_get_softexpires(period_timer); 100 hard = hrtimer_get_expires(period_timer); 101 delta = ktime_to_ns(ktime_sub(hard, soft)); 102 __hrtimer_start_range_ns(period_timer, soft, delta, 103 HRTIMER_MODE_ABS_PINNED, 0); 104 } 105} 106 107DEFINE_MUTEX(sched_domains_mutex); 108DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); 109 110static void update_rq_clock_task(struct rq *rq, s64 delta); 111 112void update_rq_clock(struct rq *rq) 113{ 114 s64 delta; 115 116 if (rq->skip_clock_update > 0) 117 return; 118 119 delta = sched_clock_cpu(cpu_of(rq)) - rq->clock; 120 rq->clock += delta; 121 update_rq_clock_task(rq, delta); 122} 123 124/* 125 * Debugging: various feature bits 126 */ 127 128#define SCHED_FEAT(name, enabled) \ 129 (1UL << __SCHED_FEAT_##name) * enabled | 130 131const_debug unsigned int sysctl_sched_features = 132#include "features.h" 133 0; 134 135#undef SCHED_FEAT 136 137#ifdef CONFIG_SCHED_DEBUG 138#define SCHED_FEAT(name, enabled) \ 139 #name , 140 141static __read_mostly char *sched_feat_names[] = { 142#include "features.h" 143 NULL 144}; 145 146#undef SCHED_FEAT 147 148static int sched_feat_show(struct seq_file *m, void *v) 149{ 150 int i; 151 152 for (i = 0; i < __SCHED_FEAT_NR; i++) { 153 if (!(sysctl_sched_features & (1UL << i))) 154 seq_puts(m, "NO_"); 155 seq_printf(m, "%s ", sched_feat_names[i]); 156 } 157 seq_puts(m, "\n"); 158 159 return 0; 160} 161 162#ifdef HAVE_JUMP_LABEL 163 164#define jump_label_key__true jump_label_key_enabled 165#define jump_label_key__false jump_label_key_disabled 166 167#define SCHED_FEAT(name, enabled) \ 168 jump_label_key__##enabled , 169 170struct jump_label_key sched_feat_keys[__SCHED_FEAT_NR] = { 171#include "features.h" 172}; 173 174#undef SCHED_FEAT 175 176static void sched_feat_disable(int i) 177{ 178 if (jump_label_enabled(&sched_feat_keys[i])) 179 jump_label_dec(&sched_feat_keys[i]); 180} 181 182static void sched_feat_enable(int i) 183{ 184 if (!jump_label_enabled(&sched_feat_keys[i])) 185 jump_label_inc(&sched_feat_keys[i]); 186} 187#else 188static void sched_feat_disable(int i) { }; 189static void sched_feat_enable(int i) { }; 190#endif /* HAVE_JUMP_LABEL */ 191 192static ssize_t 193sched_feat_write(struct file *filp, const char __user *ubuf, 194 size_t cnt, loff_t *ppos) 195{ 196 char buf[64]; 197 char *cmp; 198 int neg = 0; 199 int i; 200 201 if (cnt > 63) 202 cnt = 63; 203 204 if (copy_from_user(&buf, ubuf, cnt)) 205 return -EFAULT; 206 207 buf[cnt] = 0; 208 cmp = strstrip(buf); 209 210 if (strncmp(cmp, "NO_", 3) == 0) { 211 neg = 1; 212 cmp += 3; 213 } 214 215 for (i = 0; i < __SCHED_FEAT_NR; i++) { 216 if (strcmp(cmp, sched_feat_names[i]) == 0) { 217 if (neg) { 218 sysctl_sched_features &= ~(1UL << i); 219 sched_feat_disable(i); 220 } else { 221 sysctl_sched_features |= (1UL << i); 222 sched_feat_enable(i); 223 } 224 break; 225 } 226 } 227 228 if (i == __SCHED_FEAT_NR) 229 return -EINVAL; 230 231 *ppos += cnt; 232 233 return cnt; 234} 235 236static int sched_feat_open(struct inode *inode, struct file *filp) 237{ 238 return single_open(filp, sched_feat_show, NULL); 239} 240 241static const struct file_operations sched_feat_fops = { 242 .open = sched_feat_open, 243 .write = sched_feat_write, 244 .read = seq_read, 245 .llseek = seq_lseek, 246 .release = single_release, 247}; 248 249static __init int sched_init_debug(void) 250{ 251 debugfs_create_file("sched_features", 0644, NULL, NULL, 252 &sched_feat_fops); 253 254 return 0; 255} 256late_initcall(sched_init_debug); 257#endif /* CONFIG_SCHED_DEBUG */ 258 259/* 260 * Number of tasks to iterate in a single balance run. 261 * Limited because this is done with IRQs disabled. 262 */ 263const_debug unsigned int sysctl_sched_nr_migrate = 32; 264 265/* 266 * period over which we average the RT time consumption, measured 267 * in ms. 268 * 269 * default: 1s 270 */ 271const_debug unsigned int sysctl_sched_time_avg = MSEC_PER_SEC; 272 273/* 274 * period over which we measure -rt task cpu usage in us. 275 * default: 1s 276 */ 277unsigned int sysctl_sched_rt_period = 1000000; 278 279__read_mostly int scheduler_running; 280 281/* 282 * part of the period that we allow rt tasks to run in us. 283 * default: 0.95s 284 */ 285int sysctl_sched_rt_runtime = 950000; 286 287 288 289/* 290 * __task_rq_lock - lock the rq @p resides on. 291 */ 292static inline struct rq *__task_rq_lock(struct task_struct *p) 293 __acquires(rq->lock) 294{ 295 struct rq *rq; 296 297 lockdep_assert_held(&p->pi_lock); 298 299 for (;;) { 300 rq = task_rq(p); 301 raw_spin_lock(&rq->lock); 302 if (likely(rq == task_rq(p))) 303 return rq; 304 raw_spin_unlock(&rq->lock); 305 } 306} 307 308/* 309 * task_rq_lock - lock p->pi_lock and lock the rq @p resides on. 310 */ 311static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags) 312 __acquires(p->pi_lock) 313 __acquires(rq->lock) 314{ 315 struct rq *rq; 316 317 for (;;) { 318 raw_spin_lock_irqsave(&p->pi_lock, *flags); 319 rq = task_rq(p); 320 raw_spin_lock(&rq->lock); 321 if (likely(rq == task_rq(p))) 322 return rq; 323 raw_spin_unlock(&rq->lock); 324 raw_spin_unlock_irqrestore(&p->pi_lock, *flags); 325 } 326} 327 328static void __task_rq_unlock(struct rq *rq) 329 __releases(rq->lock) 330{ 331 raw_spin_unlock(&rq->lock); 332} 333 334static inline void 335task_rq_unlock(struct rq *rq, struct task_struct *p, unsigned long *flags) 336 __releases(rq->lock) 337 __releases(p->pi_lock) 338{ 339 raw_spin_unlock(&rq->lock); 340 raw_spin_unlock_irqrestore(&p->pi_lock, *flags); 341} 342 343/* 344 * this_rq_lock - lock this runqueue and disable interrupts. 345 */ 346static struct rq *this_rq_lock(void) 347 __acquires(rq->lock) 348{ 349 struct rq *rq; 350 351 local_irq_disable(); 352 rq = this_rq(); 353 raw_spin_lock(&rq->lock); 354 355 return rq; 356} 357 358#ifdef CONFIG_SCHED_HRTICK 359/* 360 * Use HR-timers to deliver accurate preemption points. 361 * 362 * Its all a bit involved since we cannot program an hrt while holding the 363 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a 364 * reschedule event. 365 * 366 * When we get rescheduled we reprogram the hrtick_timer outside of the 367 * rq->lock. 368 */ 369 370static void hrtick_clear(struct rq *rq) 371{ 372 if (hrtimer_active(&rq->hrtick_timer)) 373 hrtimer_cancel(&rq->hrtick_timer); 374} 375 376/* 377 * High-resolution timer tick. 378 * Runs from hardirq context with interrupts disabled. 379 */ 380static enum hrtimer_restart hrtick(struct hrtimer *timer) 381{ 382 struct rq *rq = container_of(timer, struct rq, hrtick_timer); 383 384 WARN_ON_ONCE(cpu_of(rq) != smp_processor_id()); 385 386 raw_spin_lock(&rq->lock); 387 update_rq_clock(rq); 388 rq->curr->sched_class->task_tick(rq, rq->curr, 1); 389 raw_spin_unlock(&rq->lock); 390 391 return HRTIMER_NORESTART; 392} 393 394#ifdef CONFIG_SMP 395/* 396 * called from hardirq (IPI) context 397 */ 398static void __hrtick_start(void *arg) 399{ 400 struct rq *rq = arg; 401 402 raw_spin_lock(&rq->lock); 403 hrtimer_restart(&rq->hrtick_timer); 404 rq->hrtick_csd_pending = 0; 405 raw_spin_unlock(&rq->lock); 406} 407 408/* 409 * Called to set the hrtick timer state. 410 * 411 * called with rq->lock held and irqs disabled 412 */ 413void hrtick_start(struct rq *rq, u64 delay) 414{ 415 struct hrtimer *timer = &rq->hrtick_timer; 416 ktime_t time = ktime_add_ns(timer->base->get_time(), delay); 417 418 hrtimer_set_expires(timer, time); 419 420 if (rq == this_rq()) { 421 hrtimer_restart(timer); 422 } else if (!rq->hrtick_csd_pending) { 423 __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd, 0); 424 rq->hrtick_csd_pending = 1; 425 } 426} 427 428static int 429hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu) 430{ 431 int cpu = (int)(long)hcpu; 432 433 switch (action) { 434 case CPU_UP_CANCELED: 435 case CPU_UP_CANCELED_FROZEN: 436 case CPU_DOWN_PREPARE: 437 case CPU_DOWN_PREPARE_FROZEN: 438 case CPU_DEAD: 439 case CPU_DEAD_FROZEN: 440 hrtick_clear(cpu_rq(cpu)); 441 return NOTIFY_OK; 442 } 443 444 return NOTIFY_DONE; 445} 446 447static __init void init_hrtick(void) 448{ 449 hotcpu_notifier(hotplug_hrtick, 0); 450} 451#else 452/* 453 * Called to set the hrtick timer state. 454 * 455 * called with rq->lock held and irqs disabled 456 */ 457void hrtick_start(struct rq *rq, u64 delay) 458{ 459 __hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0, 460 HRTIMER_MODE_REL_PINNED, 0); 461} 462 463static inline void init_hrtick(void) 464{ 465} 466#endif /* CONFIG_SMP */ 467 468static void init_rq_hrtick(struct rq *rq) 469{ 470#ifdef CONFIG_SMP 471 rq->hrtick_csd_pending = 0; 472 473 rq->hrtick_csd.flags = 0; 474 rq->hrtick_csd.func = __hrtick_start; 475 rq->hrtick_csd.info = rq; 476#endif 477 478 hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 479 rq->hrtick_timer.function = hrtick; 480} 481#else /* CONFIG_SCHED_HRTICK */ 482static inline void hrtick_clear(struct rq *rq) 483{ 484} 485 486static inline void init_rq_hrtick(struct rq *rq) 487{ 488} 489 490static inline void init_hrtick(void) 491{ 492} 493#endif /* CONFIG_SCHED_HRTICK */ 494 495/* 496 * resched_task - mark a task 'to be rescheduled now'. 497 * 498 * On UP this means the setting of the need_resched flag, on SMP it 499 * might also involve a cross-CPU call to trigger the scheduler on 500 * the target CPU. 501 */ 502#ifdef CONFIG_SMP 503 504#ifndef tsk_is_polling 505#define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG) 506#endif 507 508void resched_task(struct task_struct *p) 509{ 510 int cpu; 511 512 assert_raw_spin_locked(&task_rq(p)->lock); 513 514 if (test_tsk_need_resched(p)) 515 return; 516 517 set_tsk_need_resched(p); 518 519 cpu = task_cpu(p); 520 if (cpu == smp_processor_id()) 521 return; 522 523 /* NEED_RESCHED must be visible before we test polling */ 524 smp_mb(); 525 if (!tsk_is_polling(p)) 526 smp_send_reschedule(cpu); 527} 528 529void resched_cpu(int cpu) 530{ 531 struct rq *rq = cpu_rq(cpu); 532 unsigned long flags; 533 534 if (!raw_spin_trylock_irqsave(&rq->lock, flags)) 535 return; 536 resched_task(cpu_curr(cpu)); 537 raw_spin_unlock_irqrestore(&rq->lock, flags); 538} 539 540#ifdef CONFIG_NO_HZ 541/* 542 * In the semi idle case, use the nearest busy cpu for migrating timers 543 * from an idle cpu. This is good for power-savings. 544 * 545 * We don't do similar optimization for completely idle system, as 546 * selecting an idle cpu will add more delays to the timers than intended 547 * (as that cpu's timer base may not be uptodate wrt jiffies etc). 548 */ 549int get_nohz_timer_target(void) 550{ 551 int cpu = smp_processor_id(); 552 int i; 553 struct sched_domain *sd; 554 555 rcu_read_lock(); 556 for_each_domain(cpu, sd) { 557 for_each_cpu(i, sched_domain_span(sd)) { 558 if (!idle_cpu(i)) { 559 cpu = i; 560 goto unlock; 561 } 562 } 563 } 564unlock: 565 rcu_read_unlock(); 566 return cpu; 567} 568/* 569 * When add_timer_on() enqueues a timer into the timer wheel of an 570 * idle CPU then this timer might expire before the next timer event 571 * which is scheduled to wake up that CPU. In case of a completely 572 * idle system the next event might even be infinite time into the 573 * future. wake_up_idle_cpu() ensures that the CPU is woken up and 574 * leaves the inner idle loop so the newly added timer is taken into 575 * account when the CPU goes back to idle and evaluates the timer 576 * wheel for the next timer event. 577 */ 578void wake_up_idle_cpu(int cpu) 579{ 580 struct rq *rq = cpu_rq(cpu); 581 582 if (cpu == smp_processor_id()) 583 return; 584 585 /* 586 * This is safe, as this function is called with the timer 587 * wheel base lock of (cpu) held. When the CPU is on the way 588 * to idle and has not yet set rq->curr to idle then it will 589 * be serialized on the timer wheel base lock and take the new 590 * timer into account automatically. 591 */ 592 if (rq->curr != rq->idle) 593 return; 594 595 /* 596 * We can set TIF_RESCHED on the idle task of the other CPU 597 * lockless. The worst case is that the other CPU runs the 598 * idle task through an additional NOOP schedule() 599 */ 600 set_tsk_need_resched(rq->idle); 601 602 /* NEED_RESCHED must be visible before we test polling */ 603 smp_mb(); 604 if (!tsk_is_polling(rq->idle)) 605 smp_send_reschedule(cpu); 606} 607 608static inline bool got_nohz_idle_kick(void) 609{ 610 int cpu = smp_processor_id(); 611 return idle_cpu(cpu) && test_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu)); 612} 613 614#else /* CONFIG_NO_HZ */ 615 616static inline bool got_nohz_idle_kick(void) 617{ 618 return false; 619} 620 621#endif /* CONFIG_NO_HZ */ 622 623void sched_avg_update(struct rq *rq) 624{ 625 s64 period = sched_avg_period(); 626 627 while ((s64)(rq->clock - rq->age_stamp) > period) { 628 /* 629 * Inline assembly required to prevent the compiler 630 * optimising this loop into a divmod call. 631 * See __iter_div_u64_rem() for another example of this. 632 */ 633 asm("" : "+rm" (rq->age_stamp)); 634 rq->age_stamp += period; 635 rq->rt_avg /= 2; 636 } 637} 638 639#else /* !CONFIG_SMP */ 640void resched_task(struct task_struct *p) 641{ 642 assert_raw_spin_locked(&task_rq(p)->lock); 643 set_tsk_need_resched(p); 644} 645#endif /* CONFIG_SMP */ 646 647#if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \ 648 (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH))) 649/* 650 * Iterate task_group tree rooted at *from, calling @down when first entering a 651 * node and @up when leaving it for the final time. 652 * 653 * Caller must hold rcu_lock or sufficient equivalent. 654 */ 655int walk_tg_tree_from(struct task_group *from, 656 tg_visitor down, tg_visitor up, void *data) 657{ 658 struct task_group *parent, *child; 659 int ret; 660 661 parent = from; 662 663down: 664 ret = (*down)(parent, data); 665 if (ret) 666 goto out; 667 list_for_each_entry_rcu(child, &parent->children, siblings) { 668 parent = child; 669 goto down; 670 671up: 672 continue; 673 } 674 ret = (*up)(parent, data); 675 if (ret || parent == from) 676 goto out; 677 678 child = parent; 679 parent = parent->parent; 680 if (parent) 681 goto up; 682out: 683 return ret; 684} 685 686int tg_nop(struct task_group *tg, void *data) 687{ 688 return 0; 689} 690#endif 691 692void update_cpu_load(struct rq *this_rq); 693 694static void set_load_weight(struct task_struct *p) 695{ 696 int prio = p->static_prio - MAX_RT_PRIO; 697 struct load_weight *load = &p->se.load; 698 699 /* 700 * SCHED_IDLE tasks get minimal weight: 701 */ 702 if (p->policy == SCHED_IDLE) { 703 load->weight = scale_load(WEIGHT_IDLEPRIO); 704 load->inv_weight = WMULT_IDLEPRIO; 705 return; 706 } 707 708 load->weight = scale_load(prio_to_weight[prio]); 709 load->inv_weight = prio_to_wmult[prio]; 710} 711 712static void enqueue_task(struct rq *rq, struct task_struct *p, int flags) 713{ 714 update_rq_clock(rq); 715 sched_info_queued(p); 716 p->sched_class->enqueue_task(rq, p, flags); 717} 718 719static void dequeue_task(struct rq *rq, struct task_struct *p, int flags) 720{ 721 update_rq_clock(rq); 722 sched_info_dequeued(p); 723 p->sched_class->dequeue_task(rq, p, flags); 724} 725 726void activate_task(struct rq *rq, struct task_struct *p, int flags) 727{ 728 if (task_contributes_to_load(p)) 729 rq->nr_uninterruptible--; 730 731 enqueue_task(rq, p, flags); 732} 733 734void deactivate_task(struct rq *rq, struct task_struct *p, int flags) 735{ 736 if (task_contributes_to_load(p)) 737 rq->nr_uninterruptible++; 738 739 dequeue_task(rq, p, flags); 740} 741 742#ifdef CONFIG_IRQ_TIME_ACCOUNTING 743 744/* 745 * There are no locks covering percpu hardirq/softirq time. 746 * They are only modified in account_system_vtime, on corresponding CPU 747 * with interrupts disabled. So, writes are safe. 748 * They are read and saved off onto struct rq in update_rq_clock(). 749 * This may result in other CPU reading this CPU's irq time and can 750 * race with irq/account_system_vtime on this CPU. We would either get old 751 * or new value with a side effect of accounting a slice of irq time to wrong 752 * task when irq is in progress while we read rq->clock. That is a worthy 753 * compromise in place of having locks on each irq in account_system_time. 754 */ 755static DEFINE_PER_CPU(u64, cpu_hardirq_time); 756static DEFINE_PER_CPU(u64, cpu_softirq_time); 757 758static DEFINE_PER_CPU(u64, irq_start_time); 759static int sched_clock_irqtime; 760 761void enable_sched_clock_irqtime(void) 762{ 763 sched_clock_irqtime = 1; 764} 765 766void disable_sched_clock_irqtime(void) 767{ 768 sched_clock_irqtime = 0; 769} 770 771#ifndef CONFIG_64BIT 772static DEFINE_PER_CPU(seqcount_t, irq_time_seq); 773 774static inline void irq_time_write_begin(void) 775{ 776 __this_cpu_inc(irq_time_seq.sequence); 777 smp_wmb(); 778} 779 780static inline void irq_time_write_end(void) 781{ 782 smp_wmb(); 783 __this_cpu_inc(irq_time_seq.sequence); 784} 785 786static inline u64 irq_time_read(int cpu) 787{ 788 u64 irq_time; 789 unsigned seq; 790 791 do { 792 seq = read_seqcount_begin(&per_cpu(irq_time_seq, cpu)); 793 irq_time = per_cpu(cpu_softirq_time, cpu) + 794 per_cpu(cpu_hardirq_time, cpu); 795 } while (read_seqcount_retry(&per_cpu(irq_time_seq, cpu), seq)); 796 797 return irq_time; 798} 799#else /* CONFIG_64BIT */ 800static inline void irq_time_write_begin(void) 801{ 802} 803 804static inline void irq_time_write_end(void) 805{ 806} 807 808static inline u64 irq_time_read(int cpu) 809{ 810 return per_cpu(cpu_softirq_time, cpu) + per_cpu(cpu_hardirq_time, cpu); 811} 812#endif /* CONFIG_64BIT */ 813 814/* 815 * Called before incrementing preempt_count on {soft,}irq_enter 816 * and before decrementing preempt_count on {soft,}irq_exit. 817 */ 818void account_system_vtime(struct task_struct *curr) 819{ 820 unsigned long flags; 821 s64 delta; 822 int cpu; 823 824 if (!sched_clock_irqtime) 825 return; 826 827 local_irq_save(flags); 828 829 cpu = smp_processor_id(); 830 delta = sched_clock_cpu(cpu) - __this_cpu_read(irq_start_time); 831 __this_cpu_add(irq_start_time, delta); 832 833 irq_time_write_begin(); 834 /* 835 * We do not account for softirq time from ksoftirqd here. 836 * We want to continue accounting softirq time to ksoftirqd thread 837 * in that case, so as not to confuse scheduler with a special task 838 * that do not consume any time, but still wants to run. 839 */ 840 if (hardirq_count()) 841 __this_cpu_add(cpu_hardirq_time, delta); 842 else if (in_serving_softirq() && curr != this_cpu_ksoftirqd()) 843 __this_cpu_add(cpu_softirq_time, delta); 844 845 irq_time_write_end(); 846 local_irq_restore(flags); 847} 848EXPORT_SYMBOL_GPL(account_system_vtime); 849 850#endif /* CONFIG_IRQ_TIME_ACCOUNTING */ 851 852#ifdef CONFIG_PARAVIRT 853static inline u64 steal_ticks(u64 steal) 854{ 855 if (unlikely(steal > NSEC_PER_SEC)) 856 return div_u64(steal, TICK_NSEC); 857 858 return __iter_div_u64_rem(steal, TICK_NSEC, &steal); 859} 860#endif 861 862static void update_rq_clock_task(struct rq *rq, s64 delta) 863{ 864/* 865 * In theory, the compile should just see 0 here, and optimize out the call 866 * to sched_rt_avg_update. But I don't trust it... 867 */ 868#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) 869 s64 steal = 0, irq_delta = 0; 870#endif 871#ifdef CONFIG_IRQ_TIME_ACCOUNTING 872 irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time; 873 874 /* 875 * Since irq_time is only updated on {soft,}irq_exit, we might run into 876 * this case when a previous update_rq_clock() happened inside a 877 * {soft,}irq region. 878 * 879 * When this happens, we stop ->clock_task and only update the 880 * prev_irq_time stamp to account for the part that fit, so that a next 881 * update will consume the rest. This ensures ->clock_task is 882 * monotonic. 883 * 884 * It does however cause some slight miss-attribution of {soft,}irq 885 * time, a more accurate solution would be to update the irq_time using 886 * the current rq->clock timestamp, except that would require using 887 * atomic ops. 888 */ 889 if (irq_delta > delta) 890 irq_delta = delta; 891 892 rq->prev_irq_time += irq_delta; 893 delta -= irq_delta; 894#endif 895#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING 896 if (static_branch((¶virt_steal_rq_enabled))) { 897 u64 st; 898 899 steal = paravirt_steal_clock(cpu_of(rq)); 900 steal -= rq->prev_steal_time_rq; 901 902 if (unlikely(steal > delta)) 903 steal = delta; 904 905 st = steal_ticks(steal); 906 steal = st * TICK_NSEC; 907 908 rq->prev_steal_time_rq += steal; 909 910 delta -= steal; 911 } 912#endif 913 914 rq->clock_task += delta; 915 916#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) 917 if ((irq_delta + steal) && sched_feat(NONTASK_POWER)) 918 sched_rt_avg_update(rq, irq_delta + steal); 919#endif 920} 921 922#ifdef CONFIG_IRQ_TIME_ACCOUNTING 923static int irqtime_account_hi_update(void) 924{ 925 u64 *cpustat = kcpustat_this_cpu->cpustat; 926 unsigned long flags; 927 u64 latest_ns; 928 int ret = 0; 929 930 local_irq_save(flags); 931 latest_ns = this_cpu_read(cpu_hardirq_time); 932 if (nsecs_to_cputime64(latest_ns) > cpustat[CPUTIME_IRQ]) 933 ret = 1; 934 local_irq_restore(flags); 935 return ret; 936} 937 938static int irqtime_account_si_update(void) 939{ 940 u64 *cpustat = kcpustat_this_cpu->cpustat; 941 unsigned long flags; 942 u64 latest_ns; 943 int ret = 0; 944 945 local_irq_save(flags); 946 latest_ns = this_cpu_read(cpu_softirq_time); 947 if (nsecs_to_cputime64(latest_ns) > cpustat[CPUTIME_SOFTIRQ]) 948 ret = 1; 949 local_irq_restore(flags); 950 return ret; 951} 952 953#else /* CONFIG_IRQ_TIME_ACCOUNTING */ 954 955#define sched_clock_irqtime (0) 956 957#endif 958 959void sched_set_stop_task(int cpu, struct task_struct *stop) 960{ 961 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 }; 962 struct task_struct *old_stop = cpu_rq(cpu)->stop; 963 964 if (stop) { 965 /* 966 * Make it appear like a SCHED_FIFO task, its something 967 * userspace knows about and won't get confused about. 968 * 969 * Also, it will make PI more or less work without too 970 * much confusion -- but then, stop work should not 971 * rely on PI working anyway. 972 */ 973 sched_setscheduler_nocheck(stop, SCHED_FIFO, ¶m); 974 975 stop->sched_class = &stop_sched_class; 976 } 977 978 cpu_rq(cpu)->stop = stop; 979 980 if (old_stop) { 981 /* 982 * Reset it back to a normal scheduling class so that 983 * it can die in pieces. 984 */ 985 old_stop->sched_class = &rt_sched_class; 986 } 987} 988 989/* 990 * __normal_prio - return the priority that is based on the static prio 991 */ 992static inline int __normal_prio(struct task_struct *p) 993{ 994 return p->static_prio; 995} 996 997/* 998 * Calculate the expected normal priority: i.e. priority 999 * without taking RT-inheritance into account. Might be 1000 * boosted by interactivity modifiers. Changes upon fork, 1001 * setprio syscalls, and whenever the interactivity 1002 * estimator recalculates. 1003 */ 1004static inline int normal_prio(struct task_struct *p) 1005{ 1006 int prio; 1007 1008 if (task_has_rt_policy(p)) 1009 prio = MAX_RT_PRIO-1 - p->rt_priority; 1010 else 1011 prio = __normal_prio(p); 1012 return prio; 1013} 1014 1015/* 1016 * Calculate the current priority, i.e. the priority 1017 * taken into account by the scheduler. This value might 1018 * be boosted by RT tasks, or might be boosted by 1019 * interactivity modifiers. Will be RT if the task got 1020 * RT-boosted. If not then it returns p->normal_prio. 1021 */ 1022static int effective_prio(struct task_struct *p) 1023{ 1024 p->normal_prio = normal_prio(p); 1025 /* 1026 * If we are RT tasks or we were boosted to RT priority, 1027 * keep the priority unchanged. Otherwise, update priority 1028 * to the normal priority: 1029 */ 1030 if (!rt_prio(p->prio)) 1031 return p->normal_prio; 1032 return p->prio; 1033} 1034 1035/** 1036 * task_curr - is this task currently executing on a CPU? 1037 * @p: the task in question. 1038 */ 1039inline int task_curr(const struct task_struct *p) 1040{ 1041 return cpu_curr(task_cpu(p)) == p; 1042} 1043 1044static inline void check_class_changed(struct rq *rq, struct task_struct *p, 1045 const struct sched_class *prev_class, 1046 int oldprio) 1047{ 1048 if (prev_class != p->sched_class) { 1049 if (prev_class->switched_from) 1050 prev_class->switched_from(rq, p); 1051 p->sched_class->switched_to(rq, p); 1052 } else if (oldprio != p->prio) 1053 p->sched_class->prio_changed(rq, p, oldprio); 1054} 1055 1056void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags) 1057{ 1058 const struct sched_class *class; 1059 1060 if (p->sched_class == rq->curr->sched_class) { 1061 rq->curr->sched_class->check_preempt_curr(rq, p, flags); 1062 } else { 1063 for_each_class(class) { 1064 if (class == rq->curr->sched_class) 1065 break; 1066 if (class == p->sched_class) { 1067 resched_task(rq->curr); 1068 break; 1069 } 1070 } 1071 } 1072 1073 /* 1074 * A queue event has occurred, and we're going to schedule. In 1075 * this case, we can save a useless back to back clock update. 1076 */ 1077 if (rq->curr->on_rq && test_tsk_need_resched(rq->curr)) 1078 rq->skip_clock_update = 1; 1079} 1080 1081#ifdef CONFIG_SMP 1082void set_task_cpu(struct task_struct *p, unsigned int new_cpu) 1083{ 1084#ifdef CONFIG_SCHED_DEBUG 1085 /* 1086 * We should never call set_task_cpu() on a blocked task, 1087 * ttwu() will sort out the placement. 1088 */ 1089 WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING && 1090 !(task_thread_info(p)->preempt_count & PREEMPT_ACTIVE)); 1091 1092#ifdef CONFIG_LOCKDEP 1093 /* 1094 * The caller should hold either p->pi_lock or rq->lock, when changing 1095 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks. 1096 * 1097 * sched_move_task() holds both and thus holding either pins the cgroup, 1098 * see set_task_rq(). 1099 * 1100 * Furthermore, all task_rq users should acquire both locks, see 1101 * task_rq_lock(). 1102 */ 1103 WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) || 1104 lockdep_is_held(&task_rq(p)->lock))); 1105#endif 1106#endif 1107 1108 trace_sched_migrate_task(p, new_cpu); 1109 1110 if (task_cpu(p) != new_cpu) { 1111 p->se.nr_migrations++; 1112 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, 1, NULL, 0); 1113 } 1114 1115 __set_task_cpu(p, new_cpu); 1116} 1117 1118struct migration_arg { 1119 struct task_struct *task; 1120 int dest_cpu; 1121}; 1122 1123static int migration_cpu_stop(void *data); 1124 1125/* 1126 * wait_task_inactive - wait for a thread to unschedule. 1127 * 1128 * If @match_state is nonzero, it's the @p->state value just checked and 1129 * not expected to change. If it changes, i.e. @p might have woken up, 1130 * then return zero. When we succeed in waiting for @p to be off its CPU, 1131 * we return a positive number (its total switch count). If a second call 1132 * a short while later returns the same number, the caller can be sure that 1133 * @p has remained unscheduled the whole time. 1134 * 1135 * The caller must ensure that the task *will* unschedule sometime soon, 1136 * else this function might spin for a *long* time. This function can't 1137 * be called with interrupts off, or it may introduce deadlock with 1138 * smp_call_function() if an IPI is sent by the same process we are 1139 * waiting to become inactive. 1140 */ 1141unsigned long wait_task_inactive(struct task_struct *p, long match_state) 1142{ 1143 unsigned long flags; 1144 int running, on_rq; 1145 unsigned long ncsw; 1146 struct rq *rq; 1147 1148 for (;;) { 1149 /* 1150 * We do the initial early heuristics without holding 1151 * any task-queue locks at all. We'll only try to get 1152 * the runqueue lock when things look like they will 1153 * work out! 1154 */ 1155 rq = task_rq(p); 1156 1157 /* 1158 * If the task is actively running on another CPU 1159 * still, just relax and busy-wait without holding 1160 * any locks. 1161 * 1162 * NOTE! Since we don't hold any locks, it's not 1163 * even sure that "rq" stays as the right runqueue! 1164 * But we don't care, since "task_running()" will 1165 * return false if the runqueue has changed and p 1166 * is actually now running somewhere else! 1167 */ 1168 while (task_running(rq, p)) { 1169 if (match_state && unlikely(p->state != match_state)) 1170 return 0; 1171 cpu_relax(); 1172 } 1173 1174 /* 1175 * Ok, time to look more closely! We need the rq 1176 * lock now, to be *sure*. If we're wrong, we'll 1177 * just go back and repeat. 1178 */ 1179 rq = task_rq_lock(p, &flags); 1180 trace_sched_wait_task(p); 1181 running = task_running(rq, p); 1182 on_rq = p->on_rq; 1183 ncsw = 0; 1184 if (!match_state || p->state == match_state) 1185 ncsw = p->nvcsw | LONG_MIN; /* sets MSB */ 1186 task_rq_unlock(rq, p, &flags); 1187 1188 /* 1189 * If it changed from the expected state, bail out now. 1190 */ 1191 if (unlikely(!ncsw)) 1192 break; 1193 1194 /* 1195 * Was it really running after all now that we 1196 * checked with the proper locks actually held? 1197 * 1198 * Oops. Go back and try again.. 1199 */ 1200 if (unlikely(running)) { 1201 cpu_relax(); 1202 continue; 1203 } 1204 1205 /* 1206 * It's not enough that it's not actively running, 1207 * it must be off the runqueue _entirely_, and not 1208 * preempted! 1209 * 1210 * So if it was still runnable (but just not actively 1211 * running right now), it's preempted, and we should 1212 * yield - it could be a while. 1213 */ 1214 if (unlikely(on_rq)) { 1215 ktime_t to = ktime_set(0, NSEC_PER_SEC/HZ); 1216 1217 set_current_state(TASK_UNINTERRUPTIBLE); 1218 schedule_hrtimeout(&to, HRTIMER_MODE_REL); 1219 continue; 1220 } 1221 1222 /* 1223 * Ahh, all good. It wasn't running, and it wasn't 1224 * runnable, which means that it will never become 1225 * running in the future either. We're all done! 1226 */ 1227 break; 1228 } 1229 1230 return ncsw; 1231} 1232 1233/*** 1234 * kick_process - kick a running thread to enter/exit the kernel 1235 * @p: the to-be-kicked thread 1236 * 1237 * Cause a process which is running on another CPU to enter 1238 * kernel-mode, without any delay. (to get signals handled.) 1239 * 1240 * NOTE: this function doesn't have to take the runqueue lock, 1241 * because all it wants to ensure is that the remote task enters 1242 * the kernel. If the IPI races and the task has been migrated 1243 * to another CPU then no harm is done and the purpose has been 1244 * achieved as well. 1245 */ 1246void kick_process(struct task_struct *p) 1247{ 1248 int cpu; 1249 1250 preempt_disable(); 1251 cpu = task_cpu(p); 1252 if ((cpu != smp_processor_id()) && task_curr(p)) 1253 smp_send_reschedule(cpu); 1254 preempt_enable(); 1255} 1256EXPORT_SYMBOL_GPL(kick_process); 1257#endif /* CONFIG_SMP */ 1258 1259#ifdef CONFIG_SMP 1260/* 1261 * ->cpus_allowed is protected by both rq->lock and p->pi_lock 1262 */ 1263static int select_fallback_rq(int cpu, struct task_struct *p) 1264{ 1265 int dest_cpu; 1266 const struct cpumask *nodemask = cpumask_of_node(cpu_to_node(cpu)); 1267 1268 /* Look for allowed, online CPU in same node. */ 1269 for_each_cpu_and(dest_cpu, nodemask, cpu_active_mask) 1270 if (cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) 1271 return dest_cpu; 1272 1273 /* Any allowed, online CPU? */ 1274 dest_cpu = cpumask_any_and(tsk_cpus_allowed(p), cpu_active_mask); 1275 if (dest_cpu < nr_cpu_ids) 1276 return dest_cpu; 1277 1278 /* No more Mr. Nice Guy. */ 1279 dest_cpu = cpuset_cpus_allowed_fallback(p); 1280 /* 1281 * Don't tell them about moving exiting tasks or 1282 * kernel threads (both mm NULL), since they never 1283 * leave kernel. 1284 */ 1285 if (p->mm && printk_ratelimit()) { 1286 printk(KERN_INFO "process %d (%s) no longer affine to cpu%d\n", 1287 task_pid_nr(p), p->comm, cpu); 1288 } 1289 1290 return dest_cpu; 1291} 1292 1293/* 1294 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable. 1295 */ 1296static inline 1297int select_task_rq(struct task_struct *p, int sd_flags, int wake_flags) 1298{ 1299 int cpu = p->sched_class->select_task_rq(p, sd_flags, wake_flags); 1300 1301 /* 1302 * In order not to call set_task_cpu() on a blocking task we need 1303 * to rely on ttwu() to place the task on a valid ->cpus_allowed 1304 * cpu. 1305 * 1306 * Since this is common to all placement strategies, this lives here. 1307 * 1308 * [ this allows ->select_task() to simply return task_cpu(p) and 1309 * not worry about this generic constraint ] 1310 */ 1311 if (unlikely(!cpumask_test_cpu(cpu, tsk_cpus_allowed(p)) || 1312 !cpu_online(cpu))) 1313 cpu = select_fallback_rq(task_cpu(p), p); 1314 1315 return cpu; 1316} 1317 1318static void update_avg(u64 *avg, u64 sample) 1319{ 1320 s64 diff = sample - *avg; 1321 *avg += diff >> 3; 1322} 1323#endif 1324 1325static void 1326ttwu_stat(struct task_struct *p, int cpu, int wake_flags) 1327{ 1328#ifdef CONFIG_SCHEDSTATS 1329 struct rq *rq = this_rq(); 1330 1331#ifdef CONFIG_SMP 1332 int this_cpu = smp_processor_id(); 1333 1334 if (cpu == this_cpu) { 1335 schedstat_inc(rq, ttwu_local); 1336 schedstat_inc(p, se.statistics.nr_wakeups_local); 1337 } else { 1338 struct sched_domain *sd; 1339 1340 schedstat_inc(p, se.statistics.nr_wakeups_remote); 1341 rcu_read_lock(); 1342 for_each_domain(this_cpu, sd) { 1343 if (cpumask_test_cpu(cpu, sched_domain_span(sd))) { 1344 schedstat_inc(sd, ttwu_wake_remote); 1345 break; 1346 } 1347 } 1348 rcu_read_unlock(); 1349 } 1350 1351 if (wake_flags & WF_MIGRATED) 1352 schedstat_inc(p, se.statistics.nr_wakeups_migrate); 1353 1354#endif /* CONFIG_SMP */ 1355 1356 schedstat_inc(rq, ttwu_count); 1357 schedstat_inc(p, se.statistics.nr_wakeups); 1358 1359 if (wake_flags & WF_SYNC) 1360 schedstat_inc(p, se.statistics.nr_wakeups_sync); 1361 1362#endif /* CONFIG_SCHEDSTATS */ 1363} 1364 1365static void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags) 1366{ 1367 activate_task(rq, p, en_flags); 1368 p->on_rq = 1; 1369 1370 /* if a worker is waking up, notify workqueue */ 1371 if (p->flags & PF_WQ_WORKER) 1372 wq_worker_waking_up(p, cpu_of(rq)); 1373} 1374 1375/* 1376 * Mark the task runnable and perform wakeup-preemption. 1377 */ 1378static void 1379ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags) 1380{ 1381 trace_sched_wakeup(p, true); 1382 check_preempt_curr(rq, p, wake_flags); 1383 1384 p->state = TASK_RUNNING; 1385#ifdef CONFIG_SMP 1386 if (p->sched_class->task_woken) 1387 p->sched_class->task_woken(rq, p); 1388 1389 if (rq->idle_stamp) { 1390 u64 delta = rq->clock - rq->idle_stamp; 1391 u64 max = 2*sysctl_sched_migration_cost; 1392 1393 if (delta > max) 1394 rq->avg_idle = max; 1395 else 1396 update_avg(&rq->avg_idle, delta); 1397 rq->idle_stamp = 0; 1398 } 1399#endif 1400} 1401 1402static void 1403ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags) 1404{ 1405#ifdef CONFIG_SMP 1406 if (p->sched_contributes_to_load) 1407 rq->nr_uninterruptible--; 1408#endif 1409 1410 ttwu_activate(rq, p, ENQUEUE_WAKEUP | ENQUEUE_WAKING); 1411 ttwu_do_wakeup(rq, p, wake_flags); 1412} 1413 1414/* 1415 * Called in case the task @p isn't fully descheduled from its runqueue, 1416 * in this case we must do a remote wakeup. Its a 'light' wakeup though, 1417 * since all we need to do is flip p->state to TASK_RUNNING, since 1418 * the task is still ->on_rq. 1419 */ 1420static int ttwu_remote(struct task_struct *p, int wake_flags) 1421{ 1422 struct rq *rq; 1423 int ret = 0; 1424 1425 rq = __task_rq_lock(p); 1426 if (p->on_rq) { 1427 ttwu_do_wakeup(rq, p, wake_flags); 1428 ret = 1; 1429 } 1430 __task_rq_unlock(rq); 1431 1432 return ret; 1433} 1434 1435#ifdef CONFIG_SMP 1436static void sched_ttwu_pending(void) 1437{ 1438 struct rq *rq = this_rq(); 1439 struct llist_node *llist = llist_del_all(&rq->wake_list); 1440 struct task_struct *p; 1441 1442 raw_spin_lock(&rq->lock); 1443 1444 while (llist) { 1445 p = llist_entry(llist, struct task_struct, wake_entry); 1446 llist = llist_next(llist); 1447 ttwu_do_activate(rq, p, 0); 1448 } 1449 1450 raw_spin_unlock(&rq->lock); 1451} 1452 1453void scheduler_ipi(void) 1454{ 1455 if (llist_empty(&this_rq()->wake_list) && !got_nohz_idle_kick()) 1456 return; 1457 1458 /* 1459 * Not all reschedule IPI handlers call irq_enter/irq_exit, since 1460 * traditionally all their work was done from the interrupt return 1461 * path. Now that we actually do some work, we need to make sure 1462 * we do call them. 1463 * 1464 * Some archs already do call them, luckily irq_enter/exit nest 1465 * properly. 1466 * 1467 * Arguably we should visit all archs and update all handlers, 1468 * however a fair share of IPIs are still resched only so this would 1469 * somewhat pessimize the simple resched case. 1470 */ 1471 irq_enter(); 1472 sched_ttwu_pending(); 1473 1474 /* 1475 * Check if someone kicked us for doing the nohz idle load balance. 1476 */ 1477 if (unlikely(got_nohz_idle_kick() && !need_resched())) { 1478 this_rq()->idle_balance = 1; 1479 raise_softirq_irqoff(SCHED_SOFTIRQ); 1480 } 1481 irq_exit(); 1482} 1483 1484static void ttwu_queue_remote(struct task_struct *p, int cpu) 1485{ 1486 if (llist_add(&p->wake_entry, &cpu_rq(cpu)->wake_list)) 1487 smp_send_reschedule(cpu); 1488} 1489 1490#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW 1491static int ttwu_activate_remote(struct task_struct *p, int wake_flags) 1492{ 1493 struct rq *rq; 1494 int ret = 0; 1495 1496 rq = __task_rq_lock(p); 1497 if (p->on_cpu) { 1498 ttwu_activate(rq, p, ENQUEUE_WAKEUP); 1499 ttwu_do_wakeup(rq, p, wake_flags); 1500 ret = 1; 1501 } 1502 __task_rq_unlock(rq); 1503 1504 return ret; 1505 1506} 1507#endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */ 1508 1509static inline int ttwu_share_cache(int this_cpu, int that_cpu) 1510{ 1511 return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu); 1512} 1513#endif /* CONFIG_SMP */ 1514 1515static void ttwu_queue(struct task_struct *p, int cpu) 1516{ 1517 struct rq *rq = cpu_rq(cpu); 1518 1519#if defined(CONFIG_SMP) 1520 if (sched_feat(TTWU_QUEUE) && !ttwu_share_cache(smp_processor_id(), cpu)) { 1521 sched_clock_cpu(cpu); /* sync clocks x-cpu */ 1522 ttwu_queue_remote(p, cpu); 1523 return; 1524 } 1525#endif 1526 1527 raw_spin_lock(&rq->lock); 1528 ttwu_do_activate(rq, p, 0); 1529 raw_spin_unlock(&rq->lock); 1530} 1531 1532/** 1533 * try_to_wake_up - wake up a thread 1534 * @p: the thread to be awakened 1535 * @state: the mask of task states that can be woken 1536 * @wake_flags: wake modifier flags (WF_*) 1537 * 1538 * Put it on the run-queue if it's not already there. The "current" 1539 * thread is always on the run-queue (except when the actual 1540 * re-schedule is in progress), and as such you're allowed to do 1541 * the simpler "current->state = TASK_RUNNING" to mark yourself 1542 * runnable without the overhead of this. 1543 * 1544 * Returns %true if @p was woken up, %false if it was already running 1545 * or @state didn't match @p's state. 1546 */ 1547static int 1548try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) 1549{ 1550 unsigned long flags; 1551 int cpu, success = 0; 1552 1553 smp_wmb(); 1554 raw_spin_lock_irqsave(&p->pi_lock, flags); 1555 if (!(p->state & state)) 1556 goto out; 1557 1558 success = 1; /* we're going to change ->state */ 1559 cpu = task_cpu(p); 1560 1561 if (p->on_rq && ttwu_remote(p, wake_flags)) 1562 goto stat; 1563 1564#ifdef CONFIG_SMP 1565 /* 1566 * If the owning (remote) cpu is still in the middle of schedule() with 1567 * this task as prev, wait until its done referencing the task. 1568 */ 1569 while (p->on_cpu) { 1570#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW 1571 /* 1572 * In case the architecture enables interrupts in 1573 * context_switch(), we cannot busy wait, since that 1574 * would lead to deadlocks when an interrupt hits and 1575 * tries to wake up @prev. So bail and do a complete 1576 * remote wakeup. 1577 */ 1578 if (ttwu_activate_remote(p, wake_flags)) 1579 goto stat; 1580#else 1581 cpu_relax(); 1582#endif 1583 } 1584 /* 1585 * Pairs with the smp_wmb() in finish_lock_switch(). 1586 */ 1587 smp_rmb(); 1588 1589 p->sched_contributes_to_load = !!task_contributes_to_load(p); 1590 p->state = TASK_WAKING; 1591 1592 if (p->sched_class->task_waking) 1593 p->sched_class->task_waking(p); 1594 1595 cpu = select_task_rq(p, SD_BALANCE_WAKE, wake_flags); 1596 if (task_cpu(p) != cpu) { 1597 wake_flags |= WF_MIGRATED; 1598 set_task_cpu(p, cpu); 1599 } 1600#endif /* CONFIG_SMP */ 1601 1602 ttwu_queue(p, cpu); 1603stat: 1604 ttwu_stat(p, cpu, wake_flags); 1605out: 1606 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 1607 1608 return success; 1609} 1610 1611/** 1612 * try_to_wake_up_local - try to wake up a local task with rq lock held 1613 * @p: the thread to be awakened 1614 * 1615 * Put @p on the run-queue if it's not already there. The caller must 1616 * ensure that this_rq() is locked, @p is bound to this_rq() and not 1617 * the current task. 1618 */ 1619static void try_to_wake_up_local(struct task_struct *p) 1620{ 1621 struct rq *rq = task_rq(p); 1622 1623 BUG_ON(rq != this_rq()); 1624 BUG_ON(p == current); 1625 lockdep_assert_held(&rq->lock); 1626 1627 if (!raw_spin_trylock(&p->pi_lock)) { 1628 raw_spin_unlock(&rq->lock); 1629 raw_spin_lock(&p->pi_lock); 1630 raw_spin_lock(&rq->lock); 1631 } 1632 1633 if (!(p->state & TASK_NORMAL)) 1634 goto out; 1635 1636 if (!p->on_rq) 1637 ttwu_activate(rq, p, ENQUEUE_WAKEUP); 1638 1639 ttwu_do_wakeup(rq, p, 0); 1640 ttwu_stat(p, smp_processor_id(), 0); 1641out: 1642 raw_spin_unlock(&p->pi_lock); 1643} 1644 1645/** 1646 * wake_up_process - Wake up a specific process 1647 * @p: The process to be woken up. 1648 * 1649 * Attempt to wake up the nominated process and move it to the set of runnable 1650 * processes. Returns 1 if the process was woken up, 0 if it was already 1651 * running. 1652 * 1653 * It may be assumed that this function implies a write memory barrier before 1654 * changing the task state if and only if any tasks are woken up. 1655 */ 1656int wake_up_process(struct task_struct *p) 1657{ 1658 return try_to_wake_up(p, TASK_ALL, 0); 1659} 1660EXPORT_SYMBOL(wake_up_process); 1661 1662int wake_up_state(struct task_struct *p, unsigned int state) 1663{ 1664 return try_to_wake_up(p, state, 0); 1665} 1666 1667/* 1668 * Perform scheduler related setup for a newly forked process p. 1669 * p is forked by current. 1670 * 1671 * __sched_fork() is basic setup used by init_idle() too: 1672 */ 1673static void __sched_fork(struct task_struct *p) 1674{ 1675 p->on_rq = 0; 1676 1677 p->se.on_rq = 0; 1678 p->se.exec_start = 0; 1679 p->se.sum_exec_runtime = 0; 1680 p->se.prev_sum_exec_runtime = 0; 1681 p->se.nr_migrations = 0; 1682 p->se.vruntime = 0; 1683 INIT_LIST_HEAD(&p->se.group_node); 1684 1685#ifdef CONFIG_SCHEDSTATS 1686 memset(&p->se.statistics, 0, sizeof(p->se.statistics)); 1687#endif 1688 1689 INIT_LIST_HEAD(&p->rt.run_list); 1690 1691#ifdef CONFIG_PREEMPT_NOTIFIERS 1692 INIT_HLIST_HEAD(&p->preempt_notifiers); 1693#endif 1694} 1695 1696/* 1697 * fork()/clone()-time setup: 1698 */ 1699void sched_fork(struct task_struct *p) 1700{ 1701 unsigned long flags; 1702 int cpu = get_cpu(); 1703 1704 __sched_fork(p); 1705 /* 1706 * We mark the process as running here. This guarantees that 1707 * nobody will actually run it, and a signal or other external 1708 * event cannot wake it up and insert it on the runqueue either. 1709 */ 1710 p->state = TASK_RUNNING; 1711 1712 /* 1713 * Make sure we do not leak PI boosting priority to the child. 1714 */ 1715 p->prio = current->normal_prio; 1716 1717 /* 1718 * Revert to default priority/policy on fork if requested. 1719 */ 1720 if (unlikely(p->sched_reset_on_fork)) { 1721 if (task_has_rt_policy(p)) { 1722 p->policy = SCHED_NORMAL; 1723 p->static_prio = NICE_TO_PRIO(0); 1724 p->rt_priority = 0; 1725 } else if (PRIO_TO_NICE(p->static_prio) < 0) 1726 p->static_prio = NICE_TO_PRIO(0); 1727 1728 p->prio = p->normal_prio = __normal_prio(p); 1729 set_load_weight(p); 1730 1731 /* 1732 * We don't need the reset flag anymore after the fork. It has 1733 * fulfilled its duty: 1734 */ 1735 p->sched_reset_on_fork = 0; 1736 } 1737 1738 if (!rt_prio(p->prio)) 1739 p->sched_class = &fair_sched_class; 1740 1741 if (p->sched_class->task_fork) 1742 p->sched_class->task_fork(p); 1743 1744 /* 1745 * The child is not yet in the pid-hash so no cgroup attach races, 1746 * and the cgroup is pinned to this child due to cgroup_fork() 1747 * is ran before sched_fork(). 1748 * 1749 * Silence PROVE_RCU. 1750 */ 1751 raw_spin_lock_irqsave(&p->pi_lock, flags); 1752 set_task_cpu(p, cpu); 1753 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 1754 1755#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) 1756 if (likely(sched_info_on())) 1757 memset(&p->sched_info, 0, sizeof(p->sched_info)); 1758#endif 1759#if defined(CONFIG_SMP) 1760 p->on_cpu = 0; 1761#endif 1762#ifdef CONFIG_PREEMPT_COUNT 1763 /* Want to start with kernel preemption disabled. */ 1764 task_thread_info(p)->preempt_count = 1; 1765#endif 1766#ifdef CONFIG_SMP 1767 plist_node_init(&p->pushable_tasks, MAX_PRIO); 1768#endif 1769 1770 put_cpu(); 1771} 1772 1773/* 1774 * wake_up_new_task - wake up a newly created task for the first time. 1775 * 1776 * This function will do some initial scheduler statistics housekeeping 1777 * that must be done for every newly created context, then puts the task 1778 * on the runqueue and wakes it. 1779 */ 1780void wake_up_new_task(struct task_struct *p) 1781{ 1782 unsigned long flags; 1783 struct rq *rq; 1784 1785 raw_spin_lock_irqsave(&p->pi_lock, flags); 1786#ifdef CONFIG_SMP 1787 /* 1788 * Fork balancing, do it here and not earlier because: 1789 * - cpus_allowed can change in the fork path 1790 * - any previously selected cpu might disappear through hotplug 1791 */ 1792 set_task_cpu(p, select_task_rq(p, SD_BALANCE_FORK, 0)); 1793#endif 1794 1795 rq = __task_rq_lock(p); 1796 activate_task(rq, p, 0); 1797 p->on_rq = 1; 1798 trace_sched_wakeup_new(p, true); 1799 check_preempt_curr(rq, p, WF_FORK); 1800#ifdef CONFIG_SMP 1801 if (p->sched_class->task_woken) 1802 p->sched_class->task_woken(rq, p); 1803#endif 1804 task_rq_unlock(rq, p, &flags); 1805} 1806 1807#ifdef CONFIG_PREEMPT_NOTIFIERS 1808 1809/** 1810 * preempt_notifier_register - tell me when current is being preempted & rescheduled 1811 * @notifier: notifier struct to register 1812 */ 1813void preempt_notifier_register(struct preempt_notifier *notifier) 1814{ 1815 hlist_add_head(¬ifier->link, ¤t->preempt_notifiers); 1816} 1817EXPORT_SYMBOL_GPL(preempt_notifier_register); 1818 1819/** 1820 * preempt_notifier_unregister - no longer interested in preemption notifications 1821 * @notifier: notifier struct to unregister 1822 * 1823 * This is safe to call from within a preemption notifier. 1824 */ 1825void preempt_notifier_unregister(struct preempt_notifier *notifier) 1826{ 1827 hlist_del(¬ifier->link); 1828} 1829EXPORT_SYMBOL_GPL(preempt_notifier_unregister); 1830 1831static void fire_sched_in_preempt_notifiers(struct task_struct *curr) 1832{ 1833 struct preempt_notifier *notifier; 1834 struct hlist_node *node; 1835 1836 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link) 1837 notifier->ops->sched_in(notifier, raw_smp_processor_id()); 1838} 1839 1840static void 1841fire_sched_out_preempt_notifiers(struct task_struct *curr, 1842 struct task_struct *next) 1843{ 1844 struct preempt_notifier *notifier; 1845 struct hlist_node *node; 1846 1847 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link) 1848 notifier->ops->sched_out(notifier, next); 1849} 1850 1851#else /* !CONFIG_PREEMPT_NOTIFIERS */ 1852 1853static void fire_sched_in_preempt_notifiers(struct task_struct *curr) 1854{ 1855} 1856 1857static void 1858fire_sched_out_preempt_notifiers(struct task_struct *curr, 1859 struct task_struct *next) 1860{ 1861} 1862 1863#endif /* CONFIG_PREEMPT_NOTIFIERS */ 1864 1865/** 1866 * prepare_task_switch - prepare to switch tasks 1867 * @rq: the runqueue preparing to switch 1868 * @prev: the current task that is being switched out 1869 * @next: the task we are going to switch to. 1870 * 1871 * This is called with the rq lock held and interrupts off. It must 1872 * be paired with a subsequent finish_task_switch after the context 1873 * switch. 1874 * 1875 * prepare_task_switch sets up locking and calls architecture specific 1876 * hooks. 1877 */ 1878static inline void 1879prepare_task_switch(struct rq *rq, struct task_struct *prev, 1880 struct task_struct *next) 1881{ 1882 sched_info_switch(prev, next); 1883 perf_event_task_sched_out(prev, next); 1884 fire_sched_out_preempt_notifiers(prev, next); 1885 prepare_lock_switch(rq, next); 1886 prepare_arch_switch(next); 1887 trace_sched_switch(prev, next); 1888} 1889 1890/** 1891 * finish_task_switch - clean up after a task-switch 1892 * @rq: runqueue associated with task-switch 1893 * @prev: the thread we just switched away from. 1894 * 1895 * finish_task_switch must be called after the context switch, paired 1896 * with a prepare_task_switch call before the context switch. 1897 * finish_task_switch will reconcile locking set up by prepare_task_switch, 1898 * and do any other architecture-specific cleanup actions. 1899 * 1900 * Note that we may have delayed dropping an mm in context_switch(). If 1901 * so, we finish that here outside of the runqueue lock. (Doing it 1902 * with the lock held can cause deadlocks; see schedule() for 1903 * details.) 1904 */ 1905static void finish_task_switch(struct rq *rq, struct task_struct *prev) 1906 __releases(rq->lock) 1907{ 1908 struct mm_struct *mm = rq->prev_mm; 1909 long prev_state; 1910 1911 rq->prev_mm = NULL; 1912 1913 /* 1914 * A task struct has one reference for the use as "current". 1915 * If a task dies, then it sets TASK_DEAD in tsk->state and calls 1916 * schedule one last time. The schedule call will never return, and 1917 * the scheduled task must drop that reference. 1918 * The test for TASK_DEAD must occur while the runqueue locks are 1919 * still held, otherwise prev could be scheduled on another cpu, die 1920 * there before we look at prev->state, and then the reference would 1921 * be dropped twice. 1922 * Manfred Spraul <manfred@colorfullife.com> 1923 */ 1924 prev_state = prev->state; 1925 finish_arch_switch(prev); 1926#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW 1927 local_irq_disable(); 1928#endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */ 1929 perf_event_task_sched_in(prev, current); 1930#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW 1931 local_irq_enable(); 1932#endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */ 1933 finish_lock_switch(rq, prev); 1934 trace_sched_stat_sleeptime(current, rq->clock); 1935 1936 fire_sched_in_preempt_notifiers(current); 1937 if (mm) 1938 mmdrop(mm); 1939 if (unlikely(prev_state == TASK_DEAD)) { 1940 /* 1941 * Remove function-return probe instances associated with this 1942 * task and put them back on the free list. 1943 */ 1944 kprobe_flush_task(prev); 1945 put_task_struct(prev); 1946 } 1947} 1948 1949#ifdef CONFIG_SMP 1950 1951/* assumes rq->lock is held */ 1952static inline void pre_schedule(struct rq *rq, struct task_struct *prev) 1953{ 1954 if (prev->sched_class->pre_schedule) 1955 prev->sched_class->pre_schedule(rq, prev); 1956} 1957 1958/* rq->lock is NOT held, but preemption is disabled */ 1959static inline void post_schedule(struct rq *rq) 1960{ 1961 if (rq->post_schedule) { 1962 unsigned long flags; 1963 1964 raw_spin_lock_irqsave(&rq->lock, flags); 1965 if (rq->curr->sched_class->post_schedule) 1966 rq->curr->sched_class->post_schedule(rq); 1967 raw_spin_unlock_irqrestore(&rq->lock, flags); 1968 1969 rq->post_schedule = 0; 1970 } 1971} 1972 1973#else 1974 1975static inline void pre_schedule(struct rq *rq, struct task_struct *p) 1976{ 1977} 1978 1979static inline void post_schedule(struct rq *rq) 1980{ 1981} 1982 1983#endif 1984 1985/** 1986 * schedule_tail - first thing a freshly forked thread must call. 1987 * @prev: the thread we just switched away from. 1988 */ 1989asmlinkage void schedule_tail(struct task_struct *prev) 1990 __releases(rq->lock) 1991{ 1992 struct rq *rq = this_rq(); 1993 1994 finish_task_switch(rq, prev); 1995 1996 /* 1997 * FIXME: do we need to worry about rq being invalidated by the 1998 * task_switch? 1999 */ 2000 post_schedule(rq); 2001 2002#ifdef __ARCH_WANT_UNLOCKED_CTXSW 2003 /* In this case, finish_task_switch does not reenable preemption */ 2004 preempt_enable(); 2005#endif 2006 if (current->set_child_tid) 2007 put_user(task_pid_vnr(current), current->set_child_tid); 2008} 2009 2010/* 2011 * context_switch - switch to the new MM and the new 2012 * thread's register state. 2013 */ 2014static inline void 2015context_switch(struct rq *rq, struct task_struct *prev, 2016 struct task_struct *next) 2017{ 2018 struct mm_struct *mm, *oldmm; 2019 2020 prepare_task_switch(rq, prev, next); 2021 2022 mm = next->mm; 2023 oldmm = prev->active_mm; 2024 /* 2025 * For paravirt, this is coupled with an exit in switch_to to 2026 * combine the page table reload and the switch backend into 2027 * one hypercall. 2028 */ 2029 arch_start_context_switch(prev); 2030 2031 if (!mm) { 2032 next->active_mm = oldmm; 2033 atomic_inc(&oldmm->mm_count); 2034 enter_lazy_tlb(oldmm, next); 2035 } else 2036 switch_mm(oldmm, mm, next); 2037 2038 if (!prev->mm) { 2039 prev->active_mm = NULL; 2040 rq->prev_mm = oldmm; 2041 } 2042 /* 2043 * Since the runqueue lock will be released by the next 2044 * task (which is an invalid locking op but in the case 2045 * of the scheduler it's an obvious special-case), so we 2046 * do an early lockdep release here: 2047 */ 2048#ifndef __ARCH_WANT_UNLOCKED_CTXSW 2049 spin_release(&rq->lock.dep_map, 1, _THIS_IP_); 2050#endif 2051 2052 /* Here we just switch the register state and the stack. */ 2053 switch_to(prev, next, prev); 2054 2055 barrier(); 2056 /* 2057 * this_rq must be evaluated again because prev may have moved 2058 * CPUs since it called schedule(), thus the 'rq' on its stack 2059 * frame will be invalid. 2060 */ 2061 finish_task_switch(this_rq(), prev); 2062} 2063 2064/* 2065 * nr_running, nr_uninterruptible and nr_context_switches: 2066 * 2067 * externally visible scheduler statistics: current number of runnable 2068 * threads, current number of uninterruptible-sleeping threads, total 2069 * number of context switches performed since bootup. 2070 */ 2071unsigned long nr_running(void) 2072{ 2073 unsigned long i, sum = 0; 2074 2075 for_each_online_cpu(i) 2076 sum += cpu_rq(i)->nr_running; 2077 2078 return sum; 2079} 2080 2081unsigned long nr_uninterruptible(void) 2082{ 2083 unsigned long i, sum = 0; 2084 2085 for_each_possible_cpu(i) 2086 sum += cpu_rq(i)->nr_uninterruptible; 2087 2088 /* 2089 * Since we read the counters lockless, it might be slightly 2090 * inaccurate. Do not allow it to go below zero though: 2091 */ 2092 if (unlikely((long)sum < 0)) 2093 sum = 0; 2094 2095 return sum; 2096} 2097 2098unsigned long long nr_context_switches(void) 2099{ 2100 int i; 2101 unsigned long long sum = 0; 2102 2103 for_each_possible_cpu(i) 2104 sum += cpu_rq(i)->nr_switches; 2105 2106 return sum; 2107} 2108 2109unsigned long nr_iowait(void) 2110{ 2111 unsigned long i, sum = 0; 2112 2113 for_each_possible_cpu(i) 2114 sum += atomic_read(&cpu_rq(i)->nr_iowait); 2115 2116 return sum; 2117} 2118 2119unsigned long nr_iowait_cpu(int cpu) 2120{ 2121 struct rq *this = cpu_rq(cpu); 2122 return atomic_read(&this->nr_iowait); 2123} 2124 2125unsigned long this_cpu_load(void) 2126{ 2127 struct rq *this = this_rq(); 2128 return this->cpu_load[0]; 2129} 2130 2131 2132/* Variables and functions for calc_load */ 2133static atomic_long_t calc_load_tasks; 2134static unsigned long calc_load_update; 2135unsigned long avenrun[3]; 2136EXPORT_SYMBOL(avenrun); 2137 2138static long calc_load_fold_active(struct rq *this_rq) 2139{ 2140 long nr_active, delta = 0; 2141 2142 nr_active = this_rq->nr_running; 2143 nr_active += (long) this_rq->nr_uninterruptible; 2144 2145 if (nr_active != this_rq->calc_load_active) { 2146 delta = nr_active - this_rq->calc_load_active; 2147 this_rq->calc_load_active = nr_active; 2148 } 2149 2150 return delta; 2151} 2152 2153static unsigned long 2154calc_load(unsigned long load, unsigned long exp, unsigned long active) 2155{ 2156 load *= exp; 2157 load += active * (FIXED_1 - exp); 2158 load += 1UL << (FSHIFT - 1); 2159 return load >> FSHIFT; 2160} 2161 2162#ifdef CONFIG_NO_HZ 2163/* 2164 * For NO_HZ we delay the active fold to the next LOAD_FREQ update. 2165 * 2166 * When making the ILB scale, we should try to pull this in as well. 2167 */ 2168static atomic_long_t calc_load_tasks_idle; 2169 2170void calc_load_account_idle(struct rq *this_rq) 2171{ 2172 long delta; 2173 2174 delta = calc_load_fold_active(this_rq); 2175 if (delta) 2176 atomic_long_add(delta, &calc_load_tasks_idle); 2177} 2178 2179static long calc_load_fold_idle(void) 2180{ 2181 long delta = 0; 2182 2183 /* 2184 * Its got a race, we don't care... 2185 */ 2186 if (atomic_long_read(&calc_load_tasks_idle)) 2187 delta = atomic_long_xchg(&calc_load_tasks_idle, 0); 2188 2189 return delta; 2190} 2191 2192/** 2193 * fixed_power_int - compute: x^n, in O(log n) time 2194 * 2195 * @x: base of the power 2196 * @frac_bits: fractional bits of @x 2197 * @n: power to raise @x to. 2198 * 2199 * By exploiting the relation between the definition of the natural power 2200 * function: x^n := x*x*...*x (x multiplied by itself for n times), and 2201 * the binary encoding of numbers used by computers: n := \Sum n_i * 2^i, 2202 * (where: n_i \elem {0, 1}, the binary vector representing n), 2203 * we find: x^n := x^(\Sum n_i * 2^i) := \Prod x^(n_i * 2^i), which is 2204 * of course trivially computable in O(log_2 n), the length of our binary 2205 * vector. 2206 */ 2207static unsigned long 2208fixed_power_int(unsigned long x, unsigned int frac_bits, unsigned int n) 2209{ 2210 unsigned long result = 1UL << frac_bits; 2211 2212 if (n) for (;;) { 2213 if (n & 1) { 2214 result *= x; 2215 result += 1UL << (frac_bits - 1); 2216 result >>= frac_bits; 2217 } 2218 n >>= 1; 2219 if (!n) 2220 break; 2221 x *= x; 2222 x += 1UL << (frac_bits - 1); 2223 x >>= frac_bits; 2224 } 2225 2226 return result; 2227} 2228 2229/* 2230 * a1 = a0 * e + a * (1 - e) 2231 * 2232 * a2 = a1 * e + a * (1 - e) 2233 * = (a0 * e + a * (1 - e)) * e + a * (1 - e) 2234 * = a0 * e^2 + a * (1 - e) * (1 + e) 2235 * 2236 * a3 = a2 * e + a * (1 - e) 2237 * = (a0 * e^2 + a * (1 - e) * (1 + e)) * e + a * (1 - e) 2238 * = a0 * e^3 + a * (1 - e) * (1 + e + e^2) 2239 * 2240 * ... 2241 * 2242 * an = a0 * e^n + a * (1 - e) * (1 + e + ... + e^n-1) [1] 2243 * = a0 * e^n + a * (1 - e) * (1 - e^n)/(1 - e) 2244 * = a0 * e^n + a * (1 - e^n) 2245 * 2246 * [1] application of the geometric series: 2247 * 2248 * n 1 - x^(n+1) 2249 * S_n := \Sum x^i = ------------- 2250 * i=0 1 - x 2251 */ 2252static unsigned long 2253calc_load_n(unsigned long load, unsigned long exp, 2254 unsigned long active, unsigned int n) 2255{ 2256 2257 return calc_load(load, fixed_power_int(exp, FSHIFT, n), active); 2258} 2259 2260/* 2261 * NO_HZ can leave us missing all per-cpu ticks calling 2262 * calc_load_account_active(), but since an idle CPU folds its delta into 2263 * calc_load_tasks_idle per calc_load_account_idle(), all we need to do is fold 2264 * in the pending idle delta if our idle period crossed a load cycle boundary. 2265 * 2266 * Once we've updated the global active value, we need to apply the exponential 2267 * weights adjusted to the number of cycles missed. 2268 */ 2269static void calc_global_nohz(unsigned long ticks) 2270{ 2271 long delta, active, n; 2272 2273 if (time_before(jiffies, calc_load_update)) 2274 return; 2275 2276 /* 2277 * If we crossed a calc_load_update boundary, make sure to fold 2278 * any pending idle changes, the respective CPUs might have 2279 * missed the tick driven calc_load_account_active() update 2280 * due to NO_HZ. 2281 */ 2282 delta = calc_load_fold_idle(); 2283 if (delta) 2284 atomic_long_add(delta, &calc_load_tasks); 2285 2286 /* 2287 * If we were idle for multiple load cycles, apply them. 2288 */ 2289 if (ticks >= LOAD_FREQ) { 2290 n = ticks / LOAD_FREQ; 2291 2292 active = atomic_long_read(&calc_load_tasks); 2293 active = active > 0 ? active * FIXED_1 : 0; 2294 2295 avenrun[0] = calc_load_n(avenrun[0], EXP_1, active, n); 2296 avenrun[1] = calc_load_n(avenrun[1], EXP_5, active, n); 2297 avenrun[2] = calc_load_n(avenrun[2], EXP_15, active, n); 2298 2299 calc_load_update += n * LOAD_FREQ; 2300 } 2301 2302 /* 2303 * Its possible the remainder of the above division also crosses 2304 * a LOAD_FREQ period, the regular check in calc_global_load() 2305 * which comes after this will take care of that. 2306 * 2307 * Consider us being 11 ticks before a cycle completion, and us 2308 * sleeping for 4*LOAD_FREQ + 22 ticks, then the above code will 2309 * age us 4 cycles, and the test in calc_global_load() will 2310 * pick up the final one. 2311 */ 2312} 2313#else 2314void calc_load_account_idle(struct rq *this_rq) 2315{ 2316} 2317 2318static inline long calc_load_fold_idle(void) 2319{ 2320 return 0; 2321} 2322 2323static void calc_global_nohz(unsigned long ticks) 2324{ 2325} 2326#endif 2327 2328/** 2329 * get_avenrun - get the load average array 2330 * @loads: pointer to dest load array 2331 * @offset: offset to add 2332 * @shift: shift count to shift the result left 2333 * 2334 * These values are estimates at best, so no need for locking. 2335 */ 2336void get_avenrun(unsigned long *loads, unsigned long offset, int shift) 2337{ 2338 loads[0] = (avenrun[0] + offset) << shift; 2339 loads[1] = (avenrun[1] + offset) << shift; 2340 loads[2] = (avenrun[2] + offset) << shift; 2341} 2342 2343/* 2344 * calc_load - update the avenrun load estimates 10 ticks after the 2345 * CPUs have updated calc_load_tasks. 2346 */ 2347void calc_global_load(unsigned long ticks) 2348{ 2349 long active; 2350 2351 calc_global_nohz(ticks); 2352 2353 if (time_before(jiffies, calc_load_update + 10)) 2354 return; 2355 2356 active = atomic_long_read(&calc_load_tasks); 2357 active = active > 0 ? active * FIXED_1 : 0; 2358 2359 avenrun[0] = calc_load(avenrun[0], EXP_1, active); 2360 avenrun[1] = calc_load(avenrun[1], EXP_5, active); 2361 avenrun[2] = calc_load(avenrun[2], EXP_15, active); 2362 2363 calc_load_update += LOAD_FREQ; 2364} 2365 2366/* 2367 * Called from update_cpu_load() to periodically update this CPU's 2368 * active count. 2369 */ 2370static void calc_load_account_active(struct rq *this_rq) 2371{ 2372 long delta; 2373 2374 if (time_before(jiffies, this_rq->calc_load_update)) 2375 return; 2376 2377 delta = calc_load_fold_active(this_rq); 2378 delta += calc_load_fold_idle(); 2379 if (delta) 2380 atomic_long_add(delta, &calc_load_tasks); 2381 2382 this_rq->calc_load_update += LOAD_FREQ; 2383} 2384 2385/* 2386 * The exact cpuload at various idx values, calculated at every tick would be 2387 * load = (2^idx - 1) / 2^idx * load + 1 / 2^idx * cur_load 2388 * 2389 * If a cpu misses updates for n-1 ticks (as it was idle) and update gets called 2390 * on nth tick when cpu may be busy, then we have: 2391 * load = ((2^idx - 1) / 2^idx)^(n-1) * load 2392 * load = (2^idx - 1) / 2^idx) * load + 1 / 2^idx * cur_load 2393 * 2394 * decay_load_missed() below does efficient calculation of 2395 * load = ((2^idx - 1) / 2^idx)^(n-1) * load 2396 * avoiding 0..n-1 loop doing load = ((2^idx - 1) / 2^idx) * load 2397 * 2398 * The calculation is approximated on a 128 point scale. 2399 * degrade_zero_ticks is the number of ticks after which load at any 2400 * particular idx is approximated to be zero. 2401 * degrade_factor is a precomputed table, a row for each load idx. 2402 * Each column corresponds to degradation factor for a power of two ticks, 2403 * based on 128 point scale. 2404 * Example: 2405 * row 2, col 3 (=12) says that the degradation at load idx 2 after 2406 * 8 ticks is 12/128 (which is an approximation of exact factor 3^8/4^8). 2407 * 2408 * With this power of 2 load factors, we can degrade the load n times 2409 * by looking at 1 bits in n and doing as many mult/shift instead of 2410 * n mult/shifts needed by the exact degradation. 2411 */ 2412#define DEGRADE_SHIFT 7 2413static const unsigned char 2414 degrade_zero_ticks[CPU_LOAD_IDX_MAX] = {0, 8, 32, 64, 128}; 2415static const unsigned char 2416 degrade_factor[CPU_LOAD_IDX_MAX][DEGRADE_SHIFT + 1] = { 2417 {0, 0, 0, 0, 0, 0, 0, 0}, 2418 {64, 32, 8, 0, 0, 0, 0, 0}, 2419 {96, 72, 40, 12, 1, 0, 0}, 2420 {112, 98, 75, 43, 15, 1, 0}, 2421 {120, 112, 98, 76, 45, 16, 2} }; 2422 2423/* 2424 * Update cpu_load for any missed ticks, due to tickless idle. The backlog 2425 * would be when CPU is idle and so we just decay the old load without 2426 * adding any new load. 2427 */ 2428static unsigned long 2429decay_load_missed(unsigned long load, unsigned long missed_updates, int idx) 2430{ 2431 int j = 0; 2432 2433 if (!missed_updates) 2434 return load; 2435 2436 if (missed_updates >= degrade_zero_ticks[idx]) 2437 return 0; 2438 2439 if (idx == 1) 2440 return load >> missed_updates; 2441 2442 while (missed_updates) { 2443 if (missed_updates % 2) 2444 load = (load * degrade_factor[idx][j]) >> DEGRADE_SHIFT; 2445 2446 missed_updates >>= 1; 2447 j++; 2448 } 2449 return load; 2450} 2451 2452/* 2453 * Update rq->cpu_load[] statistics. This function is usually called every 2454 * scheduler tick (TICK_NSEC). With tickless idle this will not be called 2455 * every tick. We fix it up based on jiffies. 2456 */ 2457void update_cpu_load(struct rq *this_rq) 2458{ 2459 unsigned long this_load = this_rq->load.weight; 2460 unsigned long curr_jiffies = jiffies; 2461 unsigned long pending_updates; 2462 int i, scale; 2463 2464 this_rq->nr_load_updates++; 2465 2466 /* Avoid repeated calls on same jiffy, when moving in and out of idle */ 2467 if (curr_jiffies == this_rq->last_load_update_tick) 2468 return; 2469 2470 pending_updates = curr_jiffies - this_rq->last_load_update_tick; 2471 this_rq->last_load_update_tick = curr_jiffies; 2472 2473 /* Update our load: */ 2474 this_rq->cpu_load[0] = this_load; /* Fasttrack for idx 0 */ 2475 for (i = 1, scale = 2; i < CPU_LOAD_IDX_MAX; i++, scale += scale) { 2476 unsigned long old_load, new_load; 2477 2478 /* scale is effectively 1 << i now, and >> i divides by scale */ 2479 2480 old_load = this_rq->cpu_load[i]; 2481 old_load = decay_load_missed(old_load, pending_updates - 1, i); 2482 new_load = this_load; 2483 /* 2484 * Round up the averaging division if load is increasing. This 2485 * prevents us from getting stuck on 9 if the load is 10, for 2486 * example. 2487 */ 2488 if (new_load > old_load) 2489 new_load += scale - 1; 2490 2491 this_rq->cpu_load[i] = (old_load * (scale - 1) + new_load) >> i; 2492 } 2493 2494 sched_avg_update(this_rq); 2495} 2496 2497static void update_cpu_load_active(struct rq *this_rq) 2498{ 2499 update_cpu_load(this_rq); 2500 2501 calc_load_account_active(this_rq); 2502} 2503 2504#ifdef CONFIG_SMP 2505 2506/* 2507 * sched_exec - execve() is a valuable balancing opportunity, because at 2508 * this point the task has the smallest effective memory and cache footprint. 2509 */ 2510void sched_exec(void) 2511{ 2512 struct task_struct *p = current; 2513 unsigned long flags; 2514 int dest_cpu; 2515 2516 raw_spin_lock_irqsave(&p->pi_lock, flags); 2517 dest_cpu = p->sched_class->select_task_rq(p, SD_BALANCE_EXEC, 0); 2518 if (dest_cpu == smp_processor_id()) 2519 goto unlock; 2520 2521 if (likely(cpu_active(dest_cpu))) { 2522 struct migration_arg arg = { p, dest_cpu }; 2523 2524 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 2525 stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg); 2526 return; 2527 } 2528unlock: 2529 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 2530} 2531 2532#endif 2533 2534DEFINE_PER_CPU(struct kernel_stat, kstat); 2535DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat); 2536 2537EXPORT_PER_CPU_SYMBOL(kstat); 2538EXPORT_PER_CPU_SYMBOL(kernel_cpustat); 2539 2540/* 2541 * Return any ns on the sched_clock that have not yet been accounted in 2542 * @p in case that task is currently running. 2543 * 2544 * Called with task_rq_lock() held on @rq. 2545 */ 2546static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq) 2547{ 2548 u64 ns = 0; 2549 2550 if (task_current(rq, p)) { 2551 update_rq_clock(rq); 2552 ns = rq->clock_task - p->se.exec_start; 2553 if ((s64)ns < 0) 2554 ns = 0; 2555 } 2556 2557 return ns; 2558} 2559 2560unsigned long long task_delta_exec(struct task_struct *p) 2561{ 2562 unsigned long flags; 2563 struct rq *rq; 2564 u64 ns = 0; 2565 2566 rq = task_rq_lock(p, &flags); 2567 ns = do_task_delta_exec(p, rq); 2568 task_rq_unlock(rq, p, &flags); 2569 2570 return ns; 2571} 2572 2573/* 2574 * Return accounted runtime for the task. 2575 * In case the task is currently running, return the runtime plus current's 2576 * pending runtime that have not been accounted yet. 2577 */ 2578unsigned long long task_sched_runtime(struct task_struct *p) 2579{ 2580 unsigned long flags; 2581 struct rq *rq; 2582 u64 ns = 0; 2583 2584 rq = task_rq_lock(p, &flags); 2585 ns = p->se.sum_exec_runtime + do_task_delta_exec(p, rq); 2586 task_rq_unlock(rq, p, &flags); 2587 2588 return ns; 2589} 2590 2591#ifdef CONFIG_CGROUP_CPUACCT 2592struct cgroup_subsys cpuacct_subsys; 2593struct cpuacct root_cpuacct; 2594#endif 2595 2596static inline void task_group_account_field(struct task_struct *p, int index, 2597 u64 tmp) 2598{ 2599#ifdef CONFIG_CGROUP_CPUACCT 2600 struct kernel_cpustat *kcpustat; 2601 struct cpuacct *ca; 2602#endif 2603 /* 2604 * Since all updates are sure to touch the root cgroup, we 2605 * get ourselves ahead and touch it first. If the root cgroup 2606 * is the only cgroup, then nothing else should be necessary. 2607 * 2608 */ 2609 __get_cpu_var(kernel_cpustat).cpustat[index] += tmp; 2610 2611#ifdef CONFIG_CGROUP_CPUACCT 2612 if (unlikely(!cpuacct_subsys.active)) 2613 return; 2614 2615 rcu_read_lock(); 2616 ca = task_ca(p); 2617 while (ca && (ca != &root_cpuacct)) { 2618 kcpustat = this_cpu_ptr(ca->cpustat); 2619 kcpustat->cpustat[index] += tmp; 2620 ca = parent_ca(ca); 2621 } 2622 rcu_read_unlock(); 2623#endif 2624} 2625 2626 2627/* 2628 * Account user cpu time to a process. 2629 * @p: the process that the cpu time gets accounted to 2630 * @cputime: the cpu time spent in user space since the last update 2631 * @cputime_scaled: cputime scaled by cpu frequency 2632 */ 2633void account_user_time(struct task_struct *p, cputime_t cputime, 2634 cputime_t cputime_scaled) 2635{ 2636 int index; 2637 2638 /* Add user time to process. */ 2639 p->utime += cputime; 2640 p->utimescaled += cputime_scaled; 2641 account_group_user_time(p, cputime); 2642 2643 index = (TASK_NICE(p) > 0) ? CPUTIME_NICE : CPUTIME_USER; 2644 2645 /* Add user time to cpustat. */ 2646 task_group_account_field(p, index, (__force u64) cputime); 2647 2648 /* Account for user time used */ 2649 acct_update_integrals(p); 2650} 2651 2652/* 2653 * Account guest cpu time to a process. 2654 * @p: the process that the cpu time gets accounted to 2655 * @cputime: the cpu time spent in virtual machine since the last update 2656 * @cputime_scaled: cputime scaled by cpu frequency 2657 */ 2658static void account_guest_time(struct task_struct *p, cputime_t cputime, 2659 cputime_t cputime_scaled) 2660{ 2661 u64 *cpustat = kcpustat_this_cpu->cpustat; 2662 2663 /* Add guest time to process. */ 2664 p->utime += cputime; 2665 p->utimescaled += cputime_scaled; 2666 account_group_user_time(p, cputime); 2667 p->gtime += cputime; 2668 2669 /* Add guest time to cpustat. */ 2670 if (TASK_NICE(p) > 0) { 2671 cpustat[CPUTIME_NICE] += (__force u64) cputime; 2672 cpustat[CPUTIME_GUEST_NICE] += (__force u64) cputime; 2673 } else { 2674 cpustat[CPUTIME_USER] += (__force u64) cputime; 2675 cpustat[CPUTIME_GUEST] += (__force u64) cputime; 2676 } 2677} 2678 2679/* 2680 * Account system cpu time to a process and desired cpustat field 2681 * @p: the process that the cpu time gets accounted to 2682 * @cputime: the cpu time spent in kernel space since the last update 2683 * @cputime_scaled: cputime scaled by cpu frequency 2684 * @target_cputime64: pointer to cpustat field that has to be updated 2685 */ 2686static inline 2687void __account_system_time(struct task_struct *p, cputime_t cputime, 2688 cputime_t cputime_scaled, int index) 2689{ 2690 /* Add system time to process. */ 2691 p->stime += cputime; 2692 p->stimescaled += cputime_scaled; 2693 account_group_system_time(p, cputime); 2694 2695 /* Add system time to cpustat. */ 2696 task_group_account_field(p, index, (__force u64) cputime); 2697 2698 /* Account for system time used */ 2699 acct_update_integrals(p); 2700} 2701 2702/* 2703 * Account system cpu time to a process. 2704 * @p: the process that the cpu time gets accounted to 2705 * @hardirq_offset: the offset to subtract from hardirq_count() 2706 * @cputime: the cpu time spent in kernel space since the last update 2707 * @cputime_scaled: cputime scaled by cpu frequency 2708 */ 2709void account_system_time(struct task_struct *p, int hardirq_offset, 2710 cputime_t cputime, cputime_t cputime_scaled) 2711{ 2712 int index; 2713 2714 if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) { 2715 account_guest_time(p, cputime, cputime_scaled); 2716 return; 2717 } 2718 2719 if (hardirq_count() - hardirq_offset) 2720 index = CPUTIME_IRQ; 2721 else if (in_serving_softirq()) 2722 index = CPUTIME_SOFTIRQ; 2723 else 2724 index = CPUTIME_SYSTEM; 2725 2726 __account_system_time(p, cputime, cputime_scaled, index); 2727} 2728 2729/* 2730 * Account for involuntary wait time. 2731 * @cputime: the cpu time spent in involuntary wait 2732 */ 2733void account_steal_time(cputime_t cputime) 2734{ 2735 u64 *cpustat = kcpustat_this_cpu->cpustat; 2736 2737 cpustat[CPUTIME_STEAL] += (__force u64) cputime; 2738} 2739 2740/* 2741 * Account for idle time. 2742 * @cputime: the cpu time spent in idle wait 2743 */ 2744void account_idle_time(cputime_t cputime) 2745{ 2746 u64 *cpustat = kcpustat_this_cpu->cpustat; 2747 struct rq *rq = this_rq(); 2748 2749 if (atomic_read(&rq->nr_iowait) > 0) 2750 cpustat[CPUTIME_IOWAIT] += (__force u64) cputime; 2751 else 2752 cpustat[CPUTIME_IDLE] += (__force u64) cputime; 2753} 2754 2755static __always_inline bool steal_account_process_tick(void) 2756{ 2757#ifdef CONFIG_PARAVIRT 2758 if (static_branch(¶virt_steal_enabled)) { 2759 u64 steal, st = 0; 2760 2761 steal = paravirt_steal_clock(smp_processor_id()); 2762 steal -= this_rq()->prev_steal_time; 2763 2764 st = steal_ticks(steal); 2765 this_rq()->prev_steal_time += st * TICK_NSEC; 2766 2767 account_steal_time(st); 2768 return st; 2769 } 2770#endif 2771 return false; 2772} 2773 2774#ifndef CONFIG_VIRT_CPU_ACCOUNTING 2775 2776#ifdef CONFIG_IRQ_TIME_ACCOUNTING 2777/* 2778 * Account a tick to a process and cpustat 2779 * @p: the process that the cpu time gets accounted to 2780 * @user_tick: is the tick from userspace 2781 * @rq: the pointer to rq 2782 * 2783 * Tick demultiplexing follows the order 2784 * - pending hardirq update 2785 * - pending softirq update 2786 * - user_time 2787 * - idle_time 2788 * - system time 2789 * - check for guest_time 2790 * - else account as system_time 2791 * 2792 * Check for hardirq is done both for system and user time as there is 2793 * no timer going off while we are on hardirq and hence we may never get an 2794 * opportunity to update it solely in system time. 2795 * p->stime and friends are only updated on system time and not on irq 2796 * softirq as those do not count in task exec_runtime any more. 2797 */ 2798static void irqtime_account_process_tick(struct task_struct *p, int user_tick, 2799 struct rq *rq) 2800{ 2801 cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy); 2802 u64 *cpustat = kcpustat_this_cpu->cpustat; 2803 2804 if (steal_account_process_tick()) 2805 return; 2806 2807 if (irqtime_account_hi_update()) { 2808 cpustat[CPUTIME_IRQ] += (__force u64) cputime_one_jiffy; 2809 } else if (irqtime_account_si_update()) { 2810 cpustat[CPUTIME_SOFTIRQ] += (__force u64) cputime_one_jiffy; 2811 } else if (this_cpu_ksoftirqd() == p) { 2812 /* 2813 * ksoftirqd time do not get accounted in cpu_softirq_time. 2814 * So, we have to handle it separately here. 2815 * Also, p->stime needs to be updated for ksoftirqd. 2816 */ 2817 __account_system_time(p, cputime_one_jiffy, one_jiffy_scaled, 2818 CPUTIME_SOFTIRQ); 2819 } else if (user_tick) { 2820 account_user_time(p, cputime_one_jiffy, one_jiffy_scaled); 2821 } else if (p == rq->idle) { 2822 account_idle_time(cputime_one_jiffy); 2823 } else if (p->flags & PF_VCPU) { /* System time or guest time */ 2824 account_guest_time(p, cputime_one_jiffy, one_jiffy_scaled); 2825 } else { 2826 __account_system_time(p, cputime_one_jiffy, one_jiffy_scaled, 2827 CPUTIME_SYSTEM); 2828 } 2829} 2830 2831static void irqtime_account_idle_ticks(int ticks) 2832{ 2833 int i; 2834 struct rq *rq = this_rq(); 2835 2836 for (i = 0; i < ticks; i++) 2837 irqtime_account_process_tick(current, 0, rq); 2838} 2839#else /* CONFIG_IRQ_TIME_ACCOUNTING */ 2840static void irqtime_account_idle_ticks(int ticks) {} 2841static void irqtime_account_process_tick(struct task_struct *p, int user_tick, 2842 struct rq *rq) {} 2843#endif /* CONFIG_IRQ_TIME_ACCOUNTING */ 2844 2845/* 2846 * Account a single tick of cpu time. 2847 * @p: the process that the cpu time gets accounted to 2848 * @user_tick: indicates if the tick is a user or a system tick 2849 */ 2850void account_process_tick(struct task_struct *p, int user_tick) 2851{ 2852 cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy); 2853 struct rq *rq = this_rq(); 2854 2855 if (sched_clock_irqtime) { 2856 irqtime_account_process_tick(p, user_tick, rq); 2857 return; 2858 } 2859 2860 if (steal_account_process_tick()) 2861 return; 2862 2863 if (user_tick) 2864 account_user_time(p, cputime_one_jiffy, one_jiffy_scaled); 2865 else if ((p != rq->idle) || (irq_count() != HARDIRQ_OFFSET)) 2866 account_system_time(p, HARDIRQ_OFFSET, cputime_one_jiffy, 2867 one_jiffy_scaled); 2868 else 2869 account_idle_time(cputime_one_jiffy); 2870} 2871 2872/* 2873 * Account multiple ticks of steal time. 2874 * @p: the process from which the cpu time has been stolen 2875 * @ticks: number of stolen ticks 2876 */ 2877void account_steal_ticks(unsigned long ticks) 2878{ 2879 account_steal_time(jiffies_to_cputime(ticks)); 2880} 2881 2882/* 2883 * Account multiple ticks of idle time. 2884 * @ticks: number of stolen ticks 2885 */ 2886void account_idle_ticks(unsigned long ticks) 2887{ 2888 2889 if (sched_clock_irqtime) { 2890 irqtime_account_idle_ticks(ticks); 2891 return; 2892 } 2893 2894 account_idle_time(jiffies_to_cputime(ticks)); 2895} 2896 2897#endif 2898 2899/* 2900 * Use precise platform statistics if available: 2901 */ 2902#ifdef CONFIG_VIRT_CPU_ACCOUNTING 2903void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st) 2904{ 2905 *ut = p->utime; 2906 *st = p->stime; 2907} 2908 2909void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st) 2910{ 2911 struct task_cputime cputime; 2912 2913 thread_group_cputime(p, &cputime); 2914 2915 *ut = cputime.utime; 2916 *st = cputime.stime; 2917} 2918#else 2919 2920#ifndef nsecs_to_cputime 2921# define nsecs_to_cputime(__nsecs) nsecs_to_jiffies(__nsecs) 2922#endif 2923 2924void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st) 2925{ 2926 cputime_t rtime, utime = p->utime, total = utime + p->stime; 2927 2928 /* 2929 * Use CFS's precise accounting: 2930 */ 2931 rtime = nsecs_to_cputime(p->se.sum_exec_runtime); 2932 2933 if (total) { 2934 u64 temp = (__force u64) rtime; 2935 2936 temp *= (__force u64) utime; 2937 do_div(temp, (__force u32) total); 2938 utime = (__force cputime_t) temp; 2939 } else 2940 utime = rtime; 2941 2942 /* 2943 * Compare with previous values, to keep monotonicity: 2944 */ 2945 p->prev_utime = max(p->prev_utime, utime); 2946 p->prev_stime = max(p->prev_stime, rtime - p->prev_utime); 2947 2948 *ut = p->prev_utime; 2949 *st = p->prev_stime; 2950} 2951 2952/* 2953 * Must be called with siglock held. 2954 */ 2955void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st) 2956{ 2957 struct signal_struct *sig = p->signal; 2958 struct task_cputime cputime; 2959 cputime_t rtime, utime, total; 2960 2961 thread_group_cputime(p, &cputime); 2962 2963 total = cputime.utime + cputime.stime; 2964 rtime = nsecs_to_cputime(cputime.sum_exec_runtime); 2965 2966 if (total) { 2967 u64 temp = (__force u64) rtime; 2968 2969 temp *= (__force u64) cputime.utime; 2970 do_div(temp, (__force u32) total); 2971 utime = (__force cputime_t) temp; 2972 } else 2973 utime = rtime; 2974 2975 sig->prev_utime = max(sig->prev_utime, utime); 2976 sig->prev_stime = max(sig->prev_stime, rtime - sig->prev_utime); 2977 2978 *ut = sig->prev_utime; 2979 *st = sig->prev_stime; 2980} 2981#endif 2982 2983/* 2984 * This function gets called by the timer code, with HZ frequency. 2985 * We call it with interrupts disabled. 2986 */ 2987void scheduler_tick(void) 2988{ 2989 int cpu = smp_processor_id(); 2990 struct rq *rq = cpu_rq(cpu); 2991 struct task_struct *curr = rq->curr; 2992 2993 sched_clock_tick(); 2994 2995 raw_spin_lock(&rq->lock); 2996 update_rq_clock(rq); 2997 update_cpu_load_active(rq); 2998 curr->sched_class->task_tick(rq, curr, 0); 2999 raw_spin_unlock(&rq->lock); 3000 3001 perf_event_task_tick(); 3002 3003#ifdef CONFIG_SMP 3004 rq->idle_balance = idle_cpu(cpu); 3005 trigger_load_balance(rq, cpu); 3006#endif 3007} 3008 3009notrace unsigned long get_parent_ip(unsigned long addr) 3010{ 3011 if (in_lock_functions(addr)) { 3012 addr = CALLER_ADDR2; 3013 if (in_lock_functions(addr)) 3014 addr = CALLER_ADDR3; 3015 } 3016 return addr; 3017} 3018 3019#if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \ 3020 defined(CONFIG_PREEMPT_TRACER)) 3021 3022void __kprobes add_preempt_count(int val) 3023{ 3024#ifdef CONFIG_DEBUG_PREEMPT 3025 /* 3026 * Underflow? 3027 */ 3028 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) 3029 return; 3030#endif 3031 preempt_count() += val; 3032#ifdef CONFIG_DEBUG_PREEMPT 3033 /* 3034 * Spinlock count overflowing soon? 3035 */ 3036 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= 3037 PREEMPT_MASK - 10); 3038#endif 3039 if (preempt_count() == val) 3040 trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); 3041} 3042EXPORT_SYMBOL(add_preempt_count); 3043 3044void __kprobes sub_preempt_count(int val) 3045{ 3046#ifdef CONFIG_DEBUG_PREEMPT 3047 /* 3048 * Underflow? 3049 */ 3050 if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) 3051 return; 3052 /* 3053 * Is the spinlock portion underflowing? 3054 */ 3055 if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && 3056 !(preempt_count() & PREEMPT_MASK))) 3057 return; 3058#endif 3059 3060 if (preempt_count() == val) 3061 trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); 3062 preempt_count() -= val; 3063} 3064EXPORT_SYMBOL(sub_preempt_count); 3065 3066#endif 3067 3068/* 3069 * Print scheduling while atomic bug: 3070 */ 3071static noinline void __schedule_bug(struct task_struct *prev) 3072{ 3073 struct pt_regs *regs = get_irq_regs(); 3074 3075 if (oops_in_progress) 3076 return; 3077 3078 printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n", 3079 prev->comm, prev->pid, preempt_count()); 3080 3081 debug_show_held_locks(prev); 3082 print_modules(); 3083 if (irqs_disabled()) 3084 print_irqtrace_events(prev); 3085 3086 if (regs) 3087 show_regs(regs); 3088 else 3089 dump_stack(); 3090} 3091 3092/* 3093 * Various schedule()-time debugging checks and statistics: 3094 */ 3095static inline void schedule_debug(struct task_struct *prev) 3096{ 3097 /* 3098 * Test if we are atomic. Since do_exit() needs to call into 3099 * schedule() atomically, we ignore that path for now. 3100 * Otherwise, whine if we are scheduling when we should not be. 3101 */ 3102 if (unlikely(in_atomic_preempt_off() && !prev->exit_state)) 3103 __schedule_bug(prev); 3104 rcu_sleep_check(); 3105 3106 profile_hit(SCHED_PROFILING, __builtin_return_address(0)); 3107 3108 schedstat_inc(this_rq(), sched_count); 3109} 3110 3111static void put_prev_task(struct rq *rq, struct task_struct *prev) 3112{ 3113 if (prev->on_rq || rq->skip_clock_update < 0) 3114 update_rq_clock(rq); 3115 prev->sched_class->put_prev_task(rq, prev); 3116} 3117 3118/* 3119 * Pick up the highest-prio task: 3120 */ 3121static inline struct task_struct * 3122pick_next_task(struct rq *rq) 3123{ 3124 const struct sched_class *class; 3125 struct task_struct *p; 3126 3127 /* 3128 * Optimization: we know that if all tasks are in 3129 * the fair class we can call that function directly: 3130 */ 3131 if (likely(rq->nr_running == rq->cfs.h_nr_running)) { 3132 p = fair_sched_class.pick_next_task(rq); 3133 if (likely(p)) 3134 return p; 3135 } 3136 3137 for_each_class(class) { 3138 p = class->pick_next_task(rq); 3139 if (p) 3140 return p; 3141 } 3142 3143 BUG(); /* the idle class will always have a runnable task */ 3144} 3145 3146/* 3147 * __schedule() is the main scheduler function. 3148 */ 3149static void __sched __schedule(void) 3150{ 3151 struct task_struct *prev, *next; 3152 unsigned long *switch_count; 3153 struct rq *rq; 3154 int cpu; 3155 3156need_resched: 3157 preempt_disable(); 3158 cpu = smp_processor_id(); 3159 rq = cpu_rq(cpu); 3160 rcu_note_context_switch(cpu); 3161 prev = rq->curr; 3162 3163 schedule_debug(prev); 3164 3165 if (sched_feat(HRTICK)) 3166 hrtick_clear(rq); 3167 3168 raw_spin_lock_irq(&rq->lock); 3169 3170 switch_count = &prev->nivcsw; 3171 if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { 3172 if (unlikely(signal_pending_state(prev->state, prev))) { 3173 prev->state = TASK_RUNNING; 3174 } else { 3175 deactivate_task(rq, prev, DEQUEUE_SLEEP); 3176 prev->on_rq = 0; 3177 3178 /* 3179 * If a worker went to sleep, notify and ask workqueue 3180 * whether it wants to wake up a task to maintain 3181 * concurrency. 3182 */ 3183 if (prev->flags & PF_WQ_WORKER) { 3184 struct task_struct *to_wakeup; 3185 3186 to_wakeup = wq_worker_sleeping(prev, cpu); 3187 if (to_wakeup) 3188 try_to_wake_up_local(to_wakeup); 3189 } 3190 } 3191 switch_count = &prev->nvcsw; 3192 } 3193 3194 pre_schedule(rq, prev); 3195 3196 if (unlikely(!rq->nr_running)) 3197 idle_balance(cpu, rq); 3198 3199 put_prev_task(rq, prev); 3200 next = pick_next_task(rq); 3201 clear_tsk_need_resched(prev); 3202 rq->skip_clock_update = 0; 3203 3204 if (likely(prev != next)) { 3205 rq->nr_switches++; 3206 rq->curr = next; 3207 ++*switch_count; 3208 3209 context_switch(rq, prev, next); /* unlocks the rq */ 3210 /* 3211 * The context switch have flipped the stack from under us 3212 * and restored the local variables which were saved when 3213 * this task called schedule() in the past. prev == current 3214 * is still correct, but it can be moved to another cpu/rq. 3215 */ 3216 cpu = smp_processor_id(); 3217 rq = cpu_rq(cpu); 3218 } else 3219 raw_spin_unlock_irq(&rq->lock); 3220 3221 post_schedule(rq); 3222 3223 preempt_enable_no_resched(); 3224 if (need_resched()) 3225 goto need_resched; 3226} 3227 3228static inline void sched_submit_work(struct task_struct *tsk) 3229{ 3230 if (!tsk->state) 3231 return; 3232 /* 3233 * If we are going to sleep and we have plugged IO queued, 3234 * make sure to submit it to avoid deadlocks. 3235 */ 3236 if (blk_needs_flush_plug(tsk)) 3237 blk_schedule_flush_plug(tsk); 3238} 3239 3240asmlinkage void __sched schedule(void) 3241{ 3242 struct task_struct *tsk = current; 3243 3244 sched_submit_work(tsk); 3245 __schedule(); 3246} 3247EXPORT_SYMBOL(schedule); 3248 3249#ifdef CONFIG_MUTEX_SPIN_ON_OWNER 3250 3251static inline bool owner_running(struct mutex *lock, struct task_struct *owner) 3252{ 3253 if (lock->owner != owner) 3254 return false; 3255 3256 /* 3257 * Ensure we emit the owner->on_cpu, dereference _after_ checking 3258 * lock->owner still matches owner, if that fails, owner might 3259 * point to free()d memory, if it still matches, the rcu_read_lock() 3260 * ensures the memory stays valid. 3261 */ 3262 barrier(); 3263 3264 return owner->on_cpu; 3265} 3266 3267/* 3268 * Look out! "owner" is an entirely speculative pointer 3269 * access and not reliable. 3270 */ 3271int mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner) 3272{ 3273 if (!sched_feat(OWNER_SPIN)) 3274 return 0; 3275 3276 rcu_read_lock(); 3277 while (owner_running(lock, owner)) { 3278 if (need_resched()) 3279 break; 3280 3281 arch_mutex_cpu_relax(); 3282 } 3283 rcu_read_unlock(); 3284 3285 /* 3286 * We break out the loop above on need_resched() and when the 3287 * owner changed, which is a sign for heavy contention. Return 3288 * success only when lock->owner is NULL. 3289 */ 3290 return lock->owner == NULL; 3291} 3292#endif 3293 3294#ifdef CONFIG_PREEMPT 3295/* 3296 * this is the entry point to schedule() from in-kernel preemption 3297 * off of preempt_enable. Kernel preemptions off return from interrupt 3298 * occur there and call schedule directly. 3299 */ 3300asmlinkage void __sched notrace preempt_schedule(void) 3301{ 3302 struct thread_info *ti = current_thread_info(); 3303 3304 /* 3305 * If there is a non-zero preempt_count or interrupts are disabled, 3306 * we do not want to preempt the current task. Just return.. 3307 */ 3308 if (likely(ti->preempt_count || irqs_disabled())) 3309 return; 3310 3311 do { 3312 add_preempt_count_notrace(PREEMPT_ACTIVE); 3313 __schedule(); 3314 sub_preempt_count_notrace(PREEMPT_ACTIVE); 3315 3316 /* 3317 * Check again in case we missed a preemption opportunity 3318 * between schedule and now. 3319 */ 3320 barrier(); 3321 } while (need_resched()); 3322} 3323EXPORT_SYMBOL(preempt_schedule); 3324 3325/* 3326 * this is the entry point to schedule() from kernel preemption 3327 * off of irq context. 3328 * Note, that this is called and return with irqs disabled. This will 3329 * protect us against recursive calling from irq. 3330 */ 3331asmlinkage void __sched preempt_schedule_irq(void) 3332{ 3333 struct thread_info *ti = current_thread_info(); 3334 3335 /* Catch callers which need to be fixed */ 3336 BUG_ON(ti->preempt_count || !irqs_disabled()); 3337 3338 do { 3339 add_preempt_count(PREEMPT_ACTIVE); 3340 local_irq_enable(); 3341 __schedule(); 3342 local_irq_disable(); 3343 sub_preempt_count(PREEMPT_ACTIVE); 3344 3345 /* 3346 * Check again in case we missed a preemption opportunity 3347 * between schedule and now. 3348 */ 3349 barrier(); 3350 } while (need_resched()); 3351} 3352 3353#endif /* CONFIG_PREEMPT */ 3354 3355int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags, 3356 void *key) 3357{ 3358 return try_to_wake_up(curr->private, mode, wake_flags); 3359} 3360EXPORT_SYMBOL(default_wake_function); 3361 3362/* 3363 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just 3364 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve 3365 * number) then we wake all the non-exclusive tasks and one exclusive task. 3366 * 3367 * There are circumstances in which we can try to wake a task which has already 3368 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns 3369 * zero in this (rare) case, and we handle it by continuing to scan the queue. 3370 */ 3371static void __wake_up_common(wait_queue_head_t *q, unsigned int mode, 3372 int nr_exclusive, int wake_flags, void *key) 3373{ 3374 wait_queue_t *curr, *next; 3375 3376 list_for_each_entry_safe(curr, next, &q->task_list, task_list) { 3377 unsigned flags = curr->flags; 3378 3379 if (curr->func(curr, mode, wake_flags, key) && 3380 (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive) 3381 break; 3382 } 3383} 3384 3385/** 3386 * __wake_up - wake up threads blocked on a waitqueue. 3387 * @q: the waitqueue 3388 * @mode: which threads 3389 * @nr_exclusive: how many wake-one or wake-many threads to wake up 3390 * @key: is directly passed to the wakeup function 3391 * 3392 * It may be assumed that this function implies a write memory barrier before 3393 * changing the task state if and only if any tasks are woken up. 3394 */ 3395void __wake_up(wait_queue_head_t *q, unsigned int mode, 3396 int nr_exclusive, void *key) 3397{ 3398 unsigned long flags; 3399 3400 spin_lock_irqsave(&q->lock, flags); 3401 __wake_up_common(q, mode, nr_exclusive, 0, key); 3402 spin_unlock_irqrestore(&q->lock, flags); 3403} 3404EXPORT_SYMBOL(__wake_up); 3405 3406/* 3407 * Same as __wake_up but called with the spinlock in wait_queue_head_t held. 3408 */ 3409void __wake_up_locked(wait_queue_head_t *q, unsigned int mode) 3410{ 3411 __wake_up_common(q, mode, 1, 0, NULL); 3412} 3413EXPORT_SYMBOL_GPL(__wake_up_locked); 3414 3415void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key) 3416{ 3417 __wake_up_common(q, mode, 1, 0, key); 3418} 3419EXPORT_SYMBOL_GPL(__wake_up_locked_key); 3420 3421/** 3422 * __wake_up_sync_key - wake up threads blocked on a waitqueue. 3423 * @q: the waitqueue 3424 * @mode: which threads 3425 * @nr_exclusive: how many wake-one or wake-many threads to wake up 3426 * @key: opaque value to be passed to wakeup targets 3427 * 3428 * The sync wakeup differs that the waker knows that it will schedule 3429 * away soon, so while the target thread will be woken up, it will not 3430 * be migrated to another CPU - ie. the two threads are 'synchronized' 3431 * with each other. This can prevent needless bouncing between CPUs. 3432 * 3433 * On UP it can prevent extra preemption. 3434 * 3435 * It may be assumed that this function implies a write memory barrier before 3436 * changing the task state if and only if any tasks are woken up. 3437 */ 3438void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, 3439 int nr_exclusive, void *key) 3440{ 3441 unsigned long flags; 3442 int wake_flags = WF_SYNC; 3443 3444 if (unlikely(!q)) 3445 return; 3446 3447 if (unlikely(!nr_exclusive)) 3448 wake_flags = 0; 3449 3450 spin_lock_irqsave(&q->lock, flags); 3451 __wake_up_common(q, mode, nr_exclusive, wake_flags, key); 3452 spin_unlock_irqrestore(&q->lock, flags); 3453} 3454EXPORT_SYMBOL_GPL(__wake_up_sync_key); 3455 3456/* 3457 * __wake_up_sync - see __wake_up_sync_key() 3458 */ 3459void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive) 3460{ 3461 __wake_up_sync_key(q, mode, nr_exclusive, NULL); 3462} 3463EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */ 3464 3465/** 3466 * complete: - signals a single thread waiting on this completion 3467 * @x: holds the state of this particular completion 3468 * 3469 * This will wake up a single thread waiting on this completion. Threads will be 3470 * awakened in the same order in which they were queued. 3471 * 3472 * See also complete_all(), wait_for_completion() and related routines. 3473 * 3474 * It may be assumed that this function implies a write memory barrier before 3475 * changing the task state if and only if any tasks are woken up. 3476 */ 3477void complete(struct completion *x) 3478{ 3479 unsigned long flags; 3480 3481 spin_lock_irqsave(&x->wait.lock, flags); 3482 x->done++; 3483 __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL); 3484 spin_unlock_irqrestore(&x->wait.lock, flags); 3485} 3486EXPORT_SYMBOL(complete); 3487 3488/** 3489 * complete_all: - signals all threads waiting on this completion 3490 * @x: holds the state of this particular completion 3491 * 3492 * This will wake up all threads waiting on this particular completion event. 3493 * 3494 * It may be assumed that this function implies a write memory barrier before 3495 * changing the task state if and only if any tasks are woken up. 3496 */ 3497void complete_all(struct completion *x) 3498{ 3499 unsigned long flags; 3500 3501 spin_lock_irqsave(&x->wait.lock, flags); 3502 x->done += UINT_MAX/2; 3503 __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL); 3504 spin_unlock_irqrestore(&x->wait.lock, flags); 3505} 3506EXPORT_SYMBOL(complete_all); 3507 3508static inline long __sched 3509do_wait_for_common(struct completion *x, long timeout, int state) 3510{ 3511 if (!x->done) { 3512 DECLARE_WAITQUEUE(wait, current); 3513 3514 __add_wait_queue_tail_exclusive(&x->wait, &wait); 3515 do { 3516 if (signal_pending_state(state, current)) { 3517 timeout = -ERESTARTSYS; 3518 break; 3519 } 3520 __set_current_state(state); 3521 spin_unlock_irq(&x->wait.lock); 3522 timeout = schedule_timeout(timeout); 3523 spin_lock_irq(&x->wait.lock); 3524 } while (!x->done && timeout); 3525 __remove_wait_queue(&x->wait, &wait); 3526 if (!x->done) 3527 return timeout; 3528 } 3529 x->done--; 3530 return timeout ?: 1; 3531} 3532 3533static long __sched 3534wait_for_common(struct completion *x, long timeout, int state) 3535{ 3536 might_sleep(); 3537 3538 spin_lock_irq(&x->wait.lock); 3539 timeout = do_wait_for_common(x, timeout, state); 3540 spin_unlock_irq(&x->wait.lock); 3541 return timeout; 3542} 3543 3544/** 3545 * wait_for_completion: - waits for completion of a task 3546 * @x: holds the state of this particular completion 3547 * 3548 * This waits to be signaled for completion of a specific task. It is NOT 3549 * interruptible and there is no timeout. 3550 * 3551 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout 3552 * and interrupt capability. Also see complete(). 3553 */ 3554void __sched wait_for_completion(struct completion *x) 3555{ 3556 wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE); 3557} 3558EXPORT_SYMBOL(wait_for_completion); 3559 3560/** 3561 * wait_for_completion_timeout: - waits for completion of a task (w/timeout) 3562 * @x: holds the state of this particular completion 3563 * @timeout: timeout value in jiffies 3564 * 3565 * This waits for either a completion of a specific task to be signaled or for a 3566 * specified timeout to expire. The timeout is in jiffies. It is not 3567 * interruptible. 3568 * 3569 * The return value is 0 if timed out, and positive (at least 1, or number of 3570 * jiffies left till timeout) if completed. 3571 */ 3572unsigned long __sched 3573wait_for_completion_timeout(struct completion *x, unsigned long timeout) 3574{ 3575 return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE); 3576} 3577EXPORT_SYMBOL(wait_for_completion_timeout); 3578 3579/** 3580 * wait_for_completion_interruptible: - waits for completion of a task (w/intr) 3581 * @x: holds the state of this particular completion 3582 * 3583 * This waits for completion of a specific task to be signaled. It is 3584 * interruptible. 3585 * 3586 * The return value is -ERESTARTSYS if interrupted, 0 if completed. 3587 */ 3588int __sched wait_for_completion_interruptible(struct completion *x) 3589{ 3590 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE); 3591 if (t == -ERESTARTSYS) 3592 return t; 3593 return 0; 3594} 3595EXPORT_SYMBOL(wait_for_completion_interruptible); 3596 3597/** 3598 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr)) 3599 * @x: holds the state of this particular completion 3600 * @timeout: timeout value in jiffies 3601 * 3602 * This waits for either a completion of a specific task to be signaled or for a 3603 * specified timeout to expire. It is interruptible. The timeout is in jiffies. 3604 * 3605 * The return value is -ERESTARTSYS if interrupted, 0 if timed out, 3606 * positive (at least 1, or number of jiffies left till timeout) if completed. 3607 */ 3608long __sched 3609wait_for_completion_interruptible_timeout(struct completion *x, 3610 unsigned long timeout) 3611{ 3612 return wait_for_common(x, timeout, TASK_INTERRUPTIBLE); 3613} 3614EXPORT_SYMBOL(wait_for_completion_interruptible_timeout); 3615 3616/** 3617 * wait_for_completion_killable: - waits for completion of a task (killable) 3618 * @x: holds the state of this particular completion 3619 * 3620 * This waits to be signaled for completion of a specific task. It can be 3621 * interrupted by a kill signal. 3622 * 3623 * The return value is -ERESTARTSYS if interrupted, 0 if completed. 3624 */ 3625int __sched wait_for_completion_killable(struct completion *x) 3626{ 3627 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE); 3628 if (t == -ERESTARTSYS) 3629 return t; 3630 return 0; 3631} 3632EXPORT_SYMBOL(wait_for_completion_killable); 3633 3634/** 3635 * wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable)) 3636 * @x: holds the state of this particular completion 3637 * @timeout: timeout value in jiffies 3638 * 3639 * This waits for either a completion of a specific task to be 3640 * signaled or for a specified timeout to expire. It can be 3641 * interrupted by a kill signal. 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_killable_timeout(struct completion *x, 3648 unsigned long timeout) 3649{ 3650 return wait_for_common(x, timeout, TASK_KILLABLE); 3651} 3652EXPORT_SYMBOL(wait_for_completion_killable_timeout); 3653 3654/** 3655 * try_wait_for_completion - try to decrement a completion without blocking 3656 * @x: completion structure 3657 * 3658 * Returns: 0 if a decrement cannot be done without blocking 3659 * 1 if a decrement succeeded. 3660 * 3661 * If a completion is being used as a counting completion, 3662 * attempt to decrement the counter without blocking. This 3663 * enables us to avoid waiting if the resource the completion 3664 * is protecting is not available. 3665 */ 3666bool try_wait_for_completion(struct completion *x) 3667{ 3668 unsigned long flags; 3669 int ret = 1; 3670 3671 spin_lock_irqsave(&x->wait.lock, flags); 3672 if (!x->done) 3673 ret = 0; 3674 else 3675 x->done--; 3676 spin_unlock_irqrestore(&x->wait.lock, flags); 3677 return ret; 3678} 3679EXPORT_SYMBOL(try_wait_for_completion); 3680 3681/** 3682 * completion_done - Test to see if a completion has any waiters 3683 * @x: completion structure 3684 * 3685 * Returns: 0 if there are waiters (wait_for_completion() in progress) 3686 * 1 if there are no waiters. 3687 * 3688 */ 3689bool completion_done(struct completion *x) 3690{ 3691 unsigned long flags; 3692 int ret = 1; 3693 3694 spin_lock_irqsave(&x->wait.lock, flags); 3695 if (!x->done) 3696 ret = 0; 3697 spin_unlock_irqrestore(&x->wait.lock, flags); 3698 return ret; 3699} 3700EXPORT_SYMBOL(completion_done); 3701 3702static long __sched 3703sleep_on_common(wait_queue_head_t *q, int state, long timeout) 3704{ 3705 unsigned long flags; 3706 wait_queue_t wait; 3707 3708 init_waitqueue_entry(&wait, current); 3709 3710 __set_current_state(state); 3711 3712 spin_lock_irqsave(&q->lock, flags); 3713 __add_wait_queue(q, &wait); 3714 spin_unlock(&q->lock); 3715 timeout = schedule_timeout(timeout); 3716 spin_lock_irq(&q->lock); 3717 __remove_wait_queue(q, &wait); 3718 spin_unlock_irqrestore(&q->lock, flags); 3719 3720 return timeout; 3721} 3722 3723void __sched interruptible_sleep_on(wait_queue_head_t *q) 3724{ 3725 sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); 3726} 3727EXPORT_SYMBOL(interruptible_sleep_on); 3728 3729long __sched 3730interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout) 3731{ 3732 return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout); 3733} 3734EXPORT_SYMBOL(interruptible_sleep_on_timeout); 3735 3736void __sched sleep_on(wait_queue_head_t *q) 3737{ 3738 sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); 3739} 3740EXPORT_SYMBOL(sleep_on); 3741 3742long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout) 3743{ 3744 return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout); 3745} 3746EXPORT_SYMBOL(sleep_on_timeout); 3747 3748#ifdef CONFIG_RT_MUTEXES 3749 3750/* 3751 * rt_mutex_setprio - set the current priority of a task 3752 * @p: task 3753 * @prio: prio value (kernel-internal form) 3754 * 3755 * This function changes the 'effective' priority of a task. It does 3756 * not touch ->normal_prio like __setscheduler(). 3757 * 3758 * Used by the rt_mutex code to implement priority inheritance logic. 3759 */ 3760void rt_mutex_setprio(struct task_struct *p, int prio) 3761{ 3762 int oldprio, on_rq, running; 3763 struct rq *rq; 3764 const struct sched_class *prev_class; 3765 3766 BUG_ON(prio < 0 || prio > MAX_PRIO); 3767 3768 rq = __task_rq_lock(p); 3769 3770 trace_sched_pi_setprio(p, prio); 3771 oldprio = p->prio; 3772 prev_class = p->sched_class; 3773 on_rq = p->on_rq; 3774 running = task_current(rq, p); 3775 if (on_rq) 3776 dequeue_task(rq, p, 0); 3777 if (running) 3778 p->sched_class->put_prev_task(rq, p); 3779 3780 if (rt_prio(prio)) 3781 p->sched_class = &rt_sched_class; 3782 else 3783 p->sched_class = &fair_sched_class; 3784 3785 p->prio = prio; 3786 3787 if (running) 3788 p->sched_class->set_curr_task(rq); 3789 if (on_rq) 3790 enqueue_task(rq, p, oldprio < prio ? ENQUEUE_HEAD : 0); 3791 3792 check_class_changed(rq, p, prev_class, oldprio); 3793 __task_rq_unlock(rq); 3794} 3795 3796#endif 3797 3798void set_user_nice(struct task_struct *p, long nice) 3799{ 3800 int old_prio, delta, on_rq; 3801 unsigned long flags; 3802 struct rq *rq; 3803 3804 if (TASK_NICE(p) == nice || nice < -20 || nice > 19) 3805 return; 3806 /* 3807 * We have to be careful, if called from sys_setpriority(), 3808 * the task might be in the middle of scheduling on another CPU. 3809 */ 3810 rq = task_rq_lock(p, &flags); 3811 /* 3812 * The RT priorities are set via sched_setscheduler(), but we still 3813 * allow the 'normal' nice value to be set - but as expected 3814 * it wont have any effect on scheduling until the task is 3815 * SCHED_FIFO/SCHED_RR: 3816 */ 3817 if (task_has_rt_policy(p)) { 3818 p->static_prio = NICE_TO_PRIO(nice); 3819 goto out_unlock; 3820 } 3821 on_rq = p->on_rq; 3822 if (on_rq) 3823 dequeue_task(rq, p, 0); 3824 3825 p->static_prio = NICE_TO_PRIO(nice); 3826 set_load_weight(p); 3827 old_prio = p->prio; 3828 p->prio = effective_prio(p); 3829 delta = p->prio - old_prio; 3830 3831 if (on_rq) { 3832 enqueue_task(rq, p, 0); 3833 /* 3834 * If the task increased its priority or is running and 3835 * lowered its priority, then reschedule its CPU: 3836 */ 3837 if (delta < 0 || (delta > 0 && task_running(rq, p))) 3838 resched_task(rq->curr); 3839 } 3840out_unlock: 3841 task_rq_unlock(rq, p, &flags); 3842} 3843EXPORT_SYMBOL(set_user_nice); 3844 3845/* 3846 * can_nice - check if a task can reduce its nice value 3847 * @p: task 3848 * @nice: nice value 3849 */ 3850int can_nice(const struct task_struct *p, const int nice) 3851{ 3852 /* convert nice value [19,-20] to rlimit style value [1,40] */ 3853 int nice_rlim = 20 - nice; 3854 3855 return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) || 3856 capable(CAP_SYS_NICE)); 3857} 3858 3859#ifdef __ARCH_WANT_SYS_NICE 3860 3861/* 3862 * sys_nice - change the priority of the current process. 3863 * @increment: priority increment 3864 * 3865 * sys_setpriority is a more generic, but much slower function that 3866 * does similar things. 3867 */ 3868SYSCALL_DEFINE1(nice, int, increment) 3869{ 3870 long nice, retval; 3871 3872 /* 3873 * Setpriority might change our priority at the same moment. 3874 * We don't have to worry. Conceptually one call occurs first 3875 * and we have a single winner. 3876 */ 3877 if (increment < -40) 3878 increment = -40; 3879 if (increment > 40) 3880 increment = 40; 3881 3882 nice = TASK_NICE(current) + increment; 3883 if (nice < -20) 3884 nice = -20; 3885 if (nice > 19) 3886 nice = 19; 3887 3888 if (increment < 0 && !can_nice(current, nice)) 3889 return -EPERM; 3890 3891 retval = security_task_setnice(current, nice); 3892 if (retval) 3893 return retval; 3894 3895 set_user_nice(current, nice); 3896 return 0; 3897} 3898 3899#endif 3900 3901/** 3902 * task_prio - return the priority value of a given task. 3903 * @p: the task in question. 3904 * 3905 * This is the priority value as seen by users in /proc. 3906 * RT tasks are offset by -200. Normal tasks are centered 3907 * around 0, value goes from -16 to +15. 3908 */ 3909int task_prio(const struct task_struct *p) 3910{ 3911 return p->prio - MAX_RT_PRIO; 3912} 3913 3914/** 3915 * task_nice - return the nice value of a given task. 3916 * @p: the task in question. 3917 */ 3918int task_nice(const struct task_struct *p) 3919{ 3920 return TASK_NICE(p); 3921} 3922EXPORT_SYMBOL(task_nice); 3923 3924/** 3925 * idle_cpu - is a given cpu idle currently? 3926 * @cpu: the processor in question. 3927 */ 3928int idle_cpu(int cpu) 3929{ 3930 struct rq *rq = cpu_rq(cpu); 3931 3932 if (rq->curr != rq->idle) 3933 return 0; 3934 3935 if (rq->nr_running) 3936 return 0; 3937 3938#ifdef CONFIG_SMP 3939 if (!llist_empty(&rq->wake_list)) 3940 return 0; 3941#endif 3942 3943 return 1; 3944} 3945 3946/** 3947 * idle_task - return the idle task for a given cpu. 3948 * @cpu: the processor in question. 3949 */ 3950struct task_struct *idle_task(int cpu) 3951{ 3952 return cpu_rq(cpu)->idle; 3953} 3954 3955/** 3956 * find_process_by_pid - find a process with a matching PID value. 3957 * @pid: the pid in question. 3958 */ 3959static struct task_struct *find_process_by_pid(pid_t pid) 3960{ 3961 return pid ? find_task_by_vpid(pid) : current; 3962} 3963 3964/* Actually do priority change: must hold rq lock. */ 3965static void 3966__setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio) 3967{ 3968 p->policy = policy; 3969 p->rt_priority = prio; 3970 p->normal_prio = normal_prio(p); 3971 /* we are holding p->pi_lock already */ 3972 p->prio = rt_mutex_getprio(p); 3973 if (rt_prio(p->prio)) 3974 p->sched_class = &rt_sched_class; 3975 else 3976 p->sched_class = &fair_sched_class; 3977 set_load_weight(p); 3978} 3979 3980/* 3981 * check the target process has a UID that matches the current process's 3982 */ 3983static bool check_same_owner(struct task_struct *p) 3984{ 3985 const struct cred *cred = current_cred(), *pcred; 3986 bool match; 3987 3988 rcu_read_lock(); 3989 pcred = __task_cred(p); 3990 if (cred->user->user_ns == pcred->user->user_ns) 3991 match = (cred->euid == pcred->euid || 3992 cred->euid == pcred->uid); 3993 else 3994 match = false; 3995 rcu_read_unlock(); 3996 return match; 3997} 3998 3999static int __sched_setscheduler(struct task_struct *p, int policy, 4000 const struct sched_param *param, bool user) 4001{ 4002 int retval, oldprio, oldpolicy = -1, on_rq, running; 4003 unsigned long flags; 4004 const struct sched_class *prev_class; 4005 struct rq *rq; 4006 int reset_on_fork; 4007 4008 /* may grab non-irq protected spin_locks */ 4009 BUG_ON(in_interrupt()); 4010recheck: 4011 /* double check policy once rq lock held */ 4012 if (policy < 0) { 4013 reset_on_fork = p->sched_reset_on_fork; 4014 policy = oldpolicy = p->policy; 4015 } else { 4016 reset_on_fork = !!(policy & SCHED_RESET_ON_FORK); 4017 policy &= ~SCHED_RESET_ON_FORK; 4018 4019 if (policy != SCHED_FIFO && policy != SCHED_RR && 4020 policy != SCHED_NORMAL && policy != SCHED_BATCH && 4021 policy != SCHED_IDLE) 4022 return -EINVAL; 4023 } 4024 4025 /* 4026 * Valid priorities for SCHED_FIFO and SCHED_RR are 4027 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL, 4028 * SCHED_BATCH and SCHED_IDLE is 0. 4029 */ 4030 if (param->sched_priority < 0 || 4031 (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) || 4032 (!p->mm && param->sched_priority > MAX_RT_PRIO-1)) 4033 return -EINVAL; 4034 if (rt_policy(policy) != (param->sched_priority != 0)) 4035 return -EINVAL; 4036 4037 /* 4038 * Allow unprivileged RT tasks to decrease priority: 4039 */ 4040 if (user && !capable(CAP_SYS_NICE)) { 4041 if (rt_policy(policy)) { 4042 unsigned long rlim_rtprio = 4043 task_rlimit(p, RLIMIT_RTPRIO); 4044 4045 /* can't set/change the rt policy */ 4046 if (policy != p->policy && !rlim_rtprio) 4047 return -EPERM; 4048 4049 /* can't increase priority */ 4050 if (param->sched_priority > p->rt_priority && 4051 param->sched_priority > rlim_rtprio) 4052 return -EPERM; 4053 } 4054 4055 /* 4056 * Treat SCHED_IDLE as nice 20. Only allow a switch to 4057 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it. 4058 */ 4059 if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) { 4060 if (!can_nice(p, TASK_NICE(p))) 4061 return -EPERM; 4062 } 4063 4064 /* can't change other user's priorities */ 4065 if (!check_same_owner(p)) 4066 return -EPERM; 4067 4068 /* Normal users shall not reset the sched_reset_on_fork flag */ 4069 if (p->sched_reset_on_fork && !reset_on_fork) 4070 return -EPERM; 4071 } 4072 4073 if (user) { 4074 retval = security_task_setscheduler(p); 4075 if (retval) 4076 return retval; 4077 } 4078 4079 /* 4080 * make sure no PI-waiters arrive (or leave) while we are 4081 * changing the priority of the task: 4082 * 4083 * To be able to change p->policy safely, the appropriate 4084 * runqueue lock must be held. 4085 */ 4086 rq = task_rq_lock(p, &flags); 4087 4088 /* 4089 * Changing the policy of the stop threads its a very bad idea 4090 */ 4091 if (p == rq->stop) { 4092 task_rq_unlock(rq, p, &flags); 4093 return -EINVAL; 4094 } 4095 4096 /* 4097 * If not changing anything there's no need to proceed further: 4098 */ 4099 if (unlikely(policy == p->policy && (!rt_policy(policy) || 4100 param->sched_priority == p->rt_priority))) { 4101 4102 __task_rq_unlock(rq); 4103 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 4104 return 0; 4105 } 4106 4107#ifdef CONFIG_RT_GROUP_SCHED 4108 if (user) { 4109 /* 4110 * Do not allow realtime tasks into groups that have no runtime 4111 * assigned. 4112 */ 4113 if (rt_bandwidth_enabled() && rt_policy(policy) && 4114 task_group(p)->rt_bandwidth.rt_runtime == 0 && 4115 !task_group_is_autogroup(task_group(p))) { 4116 task_rq_unlock(rq, p, &flags); 4117 return -EPERM; 4118 } 4119 } 4120#endif 4121 4122 /* recheck policy now with rq lock held */ 4123 if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { 4124 policy = oldpolicy = -1; 4125 task_rq_unlock(rq, p, &flags); 4126 goto recheck; 4127 } 4128 on_rq = p->on_rq; 4129 running = task_current(rq, p); 4130 if (on_rq) 4131 dequeue_task(rq, p, 0); 4132 if (running) 4133 p->sched_class->put_prev_task(rq, p); 4134 4135 p->sched_reset_on_fork = reset_on_fork; 4136 4137 oldprio = p->prio; 4138 prev_class = p->sched_class; 4139 __setscheduler(rq, p, policy, param->sched_priority); 4140 4141 if (running) 4142 p->sched_class->set_curr_task(rq); 4143 if (on_rq) 4144 enqueue_task(rq, p, 0); 4145 4146 check_class_changed(rq, p, prev_class, oldprio); 4147 task_rq_unlock(rq, p, &flags); 4148 4149 rt_mutex_adjust_pi(p); 4150 4151 return 0; 4152} 4153 4154/** 4155 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. 4156 * @p: the task in question. 4157 * @policy: new policy. 4158 * @param: structure containing the new RT priority. 4159 * 4160 * NOTE that the task may be already dead. 4161 */ 4162int sched_setscheduler(struct task_struct *p, int policy, 4163 const struct sched_param *param) 4164{ 4165 return __sched_setscheduler(p, policy, param, true); 4166} 4167EXPORT_SYMBOL_GPL(sched_setscheduler); 4168 4169/** 4170 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace. 4171 * @p: the task in question. 4172 * @policy: new policy. 4173 * @param: structure containing the new RT priority. 4174 * 4175 * Just like sched_setscheduler, only don't bother checking if the 4176 * current context has permission. For example, this is needed in 4177 * stop_machine(): we create temporary high priority worker threads, 4178 * but our caller might not have that capability. 4179 */ 4180int sched_setscheduler_nocheck(struct task_struct *p, int policy, 4181 const struct sched_param *param) 4182{ 4183 return __sched_setscheduler(p, policy, param, false); 4184} 4185 4186static int 4187do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) 4188{ 4189 struct sched_param lparam; 4190 struct task_struct *p; 4191 int retval; 4192 4193 if (!param || pid < 0) 4194 return -EINVAL; 4195 if (copy_from_user(&lparam, param, sizeof(struct sched_param))) 4196 return -EFAULT; 4197 4198 rcu_read_lock(); 4199 retval = -ESRCH; 4200 p = find_process_by_pid(pid); 4201 if (p != NULL) 4202 retval = sched_setscheduler(p, policy, &lparam); 4203 rcu_read_unlock(); 4204 4205 return retval; 4206} 4207 4208/** 4209 * sys_sched_setscheduler - set/change the scheduler policy and RT priority 4210 * @pid: the pid in question. 4211 * @policy: new policy. 4212 * @param: structure containing the new RT priority. 4213 */ 4214SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy, 4215 struct sched_param __user *, param) 4216{ 4217 /* negative values for policy are not valid */ 4218 if (policy < 0) 4219 return -EINVAL; 4220 4221 return do_sched_setscheduler(pid, policy, param); 4222} 4223 4224/** 4225 * sys_sched_setparam - set/change the RT priority of a thread 4226 * @pid: the pid in question. 4227 * @param: structure containing the new RT priority. 4228 */ 4229SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param) 4230{ 4231 return do_sched_setscheduler(pid, -1, param); 4232} 4233 4234/** 4235 * sys_sched_getscheduler - get the policy (scheduling class) of a thread 4236 * @pid: the pid in question. 4237 */ 4238SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid) 4239{ 4240 struct task_struct *p; 4241 int retval; 4242 4243 if (pid < 0) 4244 return -EINVAL; 4245 4246 retval = -ESRCH; 4247 rcu_read_lock(); 4248 p = find_process_by_pid(pid); 4249 if (p) { 4250 retval = security_task_getscheduler(p); 4251 if (!retval) 4252 retval = p->policy 4253 | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0); 4254 } 4255 rcu_read_unlock(); 4256 return retval; 4257} 4258 4259/** 4260 * sys_sched_getparam - get the RT priority of a thread 4261 * @pid: the pid in question. 4262 * @param: structure containing the RT priority. 4263 */ 4264SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param) 4265{ 4266 struct sched_param lp; 4267 struct task_struct *p; 4268 int retval; 4269 4270 if (!param || pid < 0) 4271 return -EINVAL; 4272 4273 rcu_read_lock(); 4274 p = find_process_by_pid(pid); 4275 retval = -ESRCH; 4276 if (!p) 4277 goto out_unlock; 4278 4279 retval = security_task_getscheduler(p); 4280 if (retval) 4281 goto out_unlock; 4282 4283 lp.sched_priority = p->rt_priority; 4284 rcu_read_unlock(); 4285 4286 /* 4287 * This one might sleep, we cannot do it with a spinlock held ... 4288 */ 4289 retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; 4290 4291 return retval; 4292 4293out_unlock: 4294 rcu_read_unlock(); 4295 return retval; 4296} 4297 4298long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) 4299{ 4300 cpumask_var_t cpus_allowed, new_mask; 4301 struct task_struct *p; 4302 int retval; 4303 4304 get_online_cpus(); 4305 rcu_read_lock(); 4306 4307 p = find_process_by_pid(pid); 4308 if (!p) { 4309 rcu_read_unlock(); 4310 put_online_cpus(); 4311 return -ESRCH; 4312 } 4313 4314 /* Prevent p going away */ 4315 get_task_struct(p); 4316 rcu_read_unlock(); 4317 4318 if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) { 4319 retval = -ENOMEM; 4320 goto out_put_task; 4321 } 4322 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) { 4323 retval = -ENOMEM; 4324 goto out_free_cpus_allowed; 4325 } 4326 retval = -EPERM; 4327 if (!check_same_owner(p) && !ns_capable(task_user_ns(p), CAP_SYS_NICE)) 4328 goto out_unlock; 4329 4330 retval = security_task_setscheduler(p); 4331 if (retval) 4332 goto out_unlock; 4333 4334 cpuset_cpus_allowed(p, cpus_allowed); 4335 cpumask_and(new_mask, in_mask, cpus_allowed); 4336again: 4337 retval = set_cpus_allowed_ptr(p, new_mask); 4338 4339 if (!retval) { 4340 cpuset_cpus_allowed(p, cpus_allowed); 4341 if (!cpumask_subset(new_mask, cpus_allowed)) { 4342 /* 4343 * We must have raced with a concurrent cpuset 4344 * update. Just reset the cpus_allowed to the 4345 * cpuset's cpus_allowed 4346 */ 4347 cpumask_copy(new_mask, cpus_allowed); 4348 goto again; 4349 } 4350 } 4351out_unlock: 4352 free_cpumask_var(new_mask); 4353out_free_cpus_allowed: 4354 free_cpumask_var(cpus_allowed); 4355out_put_task: 4356 put_task_struct(p); 4357 put_online_cpus(); 4358 return retval; 4359} 4360 4361static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, 4362 struct cpumask *new_mask) 4363{ 4364 if (len < cpumask_size()) 4365 cpumask_clear(new_mask); 4366 else if (len > cpumask_size()) 4367 len = cpumask_size(); 4368 4369 return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; 4370} 4371 4372/** 4373 * sys_sched_setaffinity - set the cpu affinity of a process 4374 * @pid: pid of the process 4375 * @len: length in bytes of the bitmask pointed to by user_mask_ptr 4376 * @user_mask_ptr: user-space pointer to the new cpu mask 4377 */ 4378SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len, 4379 unsigned long __user *, user_mask_ptr) 4380{ 4381 cpumask_var_t new_mask; 4382 int retval; 4383 4384 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) 4385 return -ENOMEM; 4386 4387 retval = get_user_cpu_mask(user_mask_ptr, len, new_mask); 4388 if (retval == 0) 4389 retval = sched_setaffinity(pid, new_mask); 4390 free_cpumask_var(new_mask); 4391 return retval; 4392} 4393 4394long sched_getaffinity(pid_t pid, struct cpumask *mask) 4395{ 4396 struct task_struct *p; 4397 unsigned long flags; 4398 int retval; 4399 4400 get_online_cpus(); 4401 rcu_read_lock(); 4402 4403 retval = -ESRCH; 4404 p = find_process_by_pid(pid); 4405 if (!p) 4406 goto out_unlock; 4407 4408 retval = security_task_getscheduler(p); 4409 if (retval) 4410 goto out_unlock; 4411 4412 raw_spin_lock_irqsave(&p->pi_lock, flags); 4413 cpumask_and(mask, &p->cpus_allowed, cpu_online_mask); 4414 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 4415 4416out_unlock: 4417 rcu_read_unlock(); 4418 put_online_cpus(); 4419 4420 return retval; 4421} 4422 4423/** 4424 * sys_sched_getaffinity - get the cpu affinity of a process 4425 * @pid: pid of the process 4426 * @len: length in bytes of the bitmask pointed to by user_mask_ptr 4427 * @user_mask_ptr: user-space pointer to hold the current cpu mask 4428 */ 4429SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len, 4430 unsigned long __user *, user_mask_ptr) 4431{ 4432 int ret; 4433 cpumask_var_t mask; 4434 4435 if ((len * BITS_PER_BYTE) < nr_cpu_ids) 4436 return -EINVAL; 4437 if (len & (sizeof(unsigned long)-1)) 4438 return -EINVAL; 4439 4440 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) 4441 return -ENOMEM; 4442 4443 ret = sched_getaffinity(pid, mask); 4444 if (ret == 0) { 4445 size_t retlen = min_t(size_t, len, cpumask_size()); 4446 4447 if (copy_to_user(user_mask_ptr, mask, retlen)) 4448 ret = -EFAULT; 4449 else 4450 ret = retlen; 4451 } 4452 free_cpumask_var(mask); 4453 4454 return ret; 4455} 4456 4457/** 4458 * sys_sched_yield - yield the current processor to other threads. 4459 * 4460 * This function yields the current CPU to other tasks. If there are no 4461 * other threads running on this CPU then this function will return. 4462 */ 4463SYSCALL_DEFINE0(sched_yield) 4464{ 4465 struct rq *rq = this_rq_lock(); 4466 4467 schedstat_inc(rq, yld_count); 4468 current->sched_class->yield_task(rq); 4469 4470 /* 4471 * Since we are going to call schedule() anyway, there's 4472 * no need to preempt or enable interrupts: 4473 */ 4474 __release(rq->lock); 4475 spin_release(&rq->lock.dep_map, 1, _THIS_IP_); 4476 do_raw_spin_unlock(&rq->lock); 4477 preempt_enable_no_resched(); 4478 4479 schedule(); 4480 4481 return 0; 4482} 4483 4484static inline int should_resched(void) 4485{ 4486 return need_resched() && !(preempt_count() & PREEMPT_ACTIVE); 4487} 4488 4489static void __cond_resched(void) 4490{ 4491 add_preempt_count(PREEMPT_ACTIVE); 4492 __schedule(); 4493 sub_preempt_count(PREEMPT_ACTIVE); 4494} 4495 4496int __sched _cond_resched(void) 4497{ 4498 if (should_resched()) { 4499 __cond_resched(); 4500 return 1; 4501 } 4502 return 0; 4503} 4504EXPORT_SYMBOL(_cond_resched); 4505 4506/* 4507 * __cond_resched_lock() - if a reschedule is pending, drop the given lock, 4508 * call schedule, and on return reacquire the lock. 4509 * 4510 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level 4511 * operations here to prevent schedule() from being called twice (once via 4512 * spin_unlock(), once by hand). 4513 */ 4514int __cond_resched_lock(spinlock_t *lock) 4515{ 4516 int resched = should_resched(); 4517 int ret = 0; 4518 4519 lockdep_assert_held(lock); 4520 4521 if (spin_needbreak(lock) || resched) { 4522 spin_unlock(lock); 4523 if (resched) 4524 __cond_resched(); 4525 else 4526 cpu_relax(); 4527 ret = 1; 4528 spin_lock(lock); 4529 } 4530 return ret; 4531} 4532EXPORT_SYMBOL(__cond_resched_lock); 4533 4534int __sched __cond_resched_softirq(void) 4535{ 4536 BUG_ON(!in_softirq()); 4537 4538 if (should_resched()) { 4539 local_bh_enable(); 4540 __cond_resched(); 4541 local_bh_disable(); 4542 return 1; 4543 } 4544 return 0; 4545} 4546EXPORT_SYMBOL(__cond_resched_softirq); 4547 4548/** 4549 * yield - yield the current processor to other threads. 4550 * 4551 * This is a shortcut for kernel-space yielding - it marks the 4552 * thread runnable and calls sys_sched_yield(). 4553 */ 4554void __sched yield(void) 4555{ 4556 set_current_state(TASK_RUNNING); 4557 sys_sched_yield(); 4558} 4559EXPORT_SYMBOL(yield); 4560 4561/** 4562 * yield_to - yield the current processor to another thread in 4563 * your thread group, or accelerate that thread toward the 4564 * processor it's on. 4565 * @p: target task 4566 * @preempt: whether task preemption is allowed or not 4567 * 4568 * It's the caller's job to ensure that the target task struct 4569 * can't go away on us before we can do any checks. 4570 * 4571 * Returns true if we indeed boosted the target task. 4572 */ 4573bool __sched yield_to(struct task_struct *p, bool preempt) 4574{ 4575 struct task_struct *curr = current; 4576 struct rq *rq, *p_rq; 4577 unsigned long flags; 4578 bool yielded = 0; 4579 4580 local_irq_save(flags); 4581 rq = this_rq(); 4582 4583again: 4584 p_rq = task_rq(p); 4585 double_rq_lock(rq, p_rq); 4586 while (task_rq(p) != p_rq) { 4587 double_rq_unlock(rq, p_rq); 4588 goto again; 4589 } 4590 4591 if (!curr->sched_class->yield_to_task) 4592 goto out; 4593 4594 if (curr->sched_class != p->sched_class) 4595 goto out; 4596 4597 if (task_running(p_rq, p) || p->state) 4598 goto out; 4599 4600 yielded = curr->sched_class->yield_to_task(rq, p, preempt); 4601 if (yielded) { 4602 schedstat_inc(rq, yld_count); 4603 /* 4604 * Make p's CPU reschedule; pick_next_entity takes care of 4605 * fairness. 4606 */ 4607 if (preempt && rq != p_rq) 4608 resched_task(p_rq->curr); 4609 } else { 4610 /* 4611 * We might have set it in task_yield_fair(), but are 4612 * not going to schedule(), so don't want to skip 4613 * the next update. 4614 */ 4615 rq->skip_clock_update = 0; 4616 } 4617 4618out: 4619 double_rq_unlock(rq, p_rq); 4620 local_irq_restore(flags); 4621 4622 if (yielded) 4623 schedule(); 4624 4625 return yielded; 4626} 4627EXPORT_SYMBOL_GPL(yield_to); 4628 4629/* 4630 * This task is about to go to sleep on IO. Increment rq->nr_iowait so 4631 * that process accounting knows that this is a task in IO wait state. 4632 */ 4633void __sched io_schedule(void) 4634{ 4635 struct rq *rq = raw_rq(); 4636 4637 delayacct_blkio_start(); 4638 atomic_inc(&rq->nr_iowait); 4639 blk_flush_plug(current); 4640 current->in_iowait = 1; 4641 schedule(); 4642 current->in_iowait = 0; 4643 atomic_dec(&rq->nr_iowait); 4644 delayacct_blkio_end(); 4645} 4646EXPORT_SYMBOL(io_schedule); 4647 4648long __sched io_schedule_timeout(long timeout) 4649{ 4650 struct rq *rq = raw_rq(); 4651 long ret; 4652 4653 delayacct_blkio_start(); 4654 atomic_inc(&rq->nr_iowait); 4655 blk_flush_plug(current); 4656 current->in_iowait = 1; 4657 ret = schedule_timeout(timeout); 4658 current->in_iowait = 0; 4659 atomic_dec(&rq->nr_iowait); 4660 delayacct_blkio_end(); 4661 return ret; 4662} 4663 4664/** 4665 * sys_sched_get_priority_max - return maximum RT priority. 4666 * @policy: scheduling class. 4667 * 4668 * this syscall returns the maximum rt_priority that can be used 4669 * by a given scheduling class. 4670 */ 4671SYSCALL_DEFINE1(sched_get_priority_max, int, policy) 4672{ 4673 int ret = -EINVAL; 4674 4675 switch (policy) { 4676 case SCHED_FIFO: 4677 case SCHED_RR: 4678 ret = MAX_USER_RT_PRIO-1; 4679 break; 4680 case SCHED_NORMAL: 4681 case SCHED_BATCH: 4682 case SCHED_IDLE: 4683 ret = 0; 4684 break; 4685 } 4686 return ret; 4687} 4688 4689/** 4690 * sys_sched_get_priority_min - return minimum RT priority. 4691 * @policy: scheduling class. 4692 * 4693 * this syscall returns the minimum rt_priority that can be used 4694 * by a given scheduling class. 4695 */ 4696SYSCALL_DEFINE1(sched_get_priority_min, int, policy) 4697{ 4698 int ret = -EINVAL; 4699 4700 switch (policy) { 4701 case SCHED_FIFO: 4702 case SCHED_RR: 4703 ret = 1; 4704 break; 4705 case SCHED_NORMAL: 4706 case SCHED_BATCH: 4707 case SCHED_IDLE: 4708 ret = 0; 4709 } 4710 return ret; 4711} 4712 4713/** 4714 * sys_sched_rr_get_interval - return the default timeslice of a process. 4715 * @pid: pid of the process. 4716 * @interval: userspace pointer to the timeslice value. 4717 * 4718 * this syscall writes the default timeslice value of a given process 4719 * into the user-space timespec buffer. A value of '0' means infinity. 4720 */ 4721SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid, 4722 struct timespec __user *, interval) 4723{ 4724 struct task_struct *p; 4725 unsigned int time_slice; 4726 unsigned long flags; 4727 struct rq *rq; 4728 int retval; 4729 struct timespec t; 4730 4731 if (pid < 0) 4732 return -EINVAL; 4733 4734 retval = -ESRCH; 4735 rcu_read_lock(); 4736 p = find_process_by_pid(pid); 4737 if (!p) 4738 goto out_unlock; 4739 4740 retval = security_task_getscheduler(p); 4741 if (retval) 4742 goto out_unlock; 4743 4744 rq = task_rq_lock(p, &flags); 4745 time_slice = p->sched_class->get_rr_interval(rq, p); 4746 task_rq_unlock(rq, p, &flags); 4747 4748 rcu_read_unlock(); 4749 jiffies_to_timespec(time_slice, &t); 4750 retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; 4751 return retval; 4752 4753out_unlock: 4754 rcu_read_unlock(); 4755 return retval; 4756} 4757 4758static const char stat_nam[] = TASK_STATE_TO_CHAR_STR; 4759 4760void sched_show_task(struct task_struct *p) 4761{ 4762 unsigned long free = 0; 4763 unsigned state; 4764 4765 state = p->state ? __ffs(p->state) + 1 : 0; 4766 printk(KERN_INFO "%-15.15s %c", p->comm, 4767 state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); 4768#if BITS_PER_LONG == 32 4769 if (state == TASK_RUNNING) 4770 printk(KERN_CONT " running "); 4771 else 4772 printk(KERN_CONT " %08lx ", thread_saved_pc(p)); 4773#else 4774 if (state == TASK_RUNNING) 4775 printk(KERN_CONT " running task "); 4776 else 4777 printk(KERN_CONT " %016lx ", thread_saved_pc(p)); 4778#endif 4779#ifdef CONFIG_DEBUG_STACK_USAGE 4780 free = stack_not_used(p); 4781#endif 4782 printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free, 4783 task_pid_nr(p), task_pid_nr(rcu_dereference(p->real_parent)), 4784 (unsigned long)task_thread_info(p)->flags); 4785 4786 show_stack(p, NULL); 4787} 4788 4789void show_state_filter(unsigned long state_filter) 4790{ 4791 struct task_struct *g, *p; 4792 4793#if BITS_PER_LONG == 32 4794 printk(KERN_INFO 4795 " task PC stack pid father\n"); 4796#else 4797 printk(KERN_INFO 4798 " task PC stack pid father\n"); 4799#endif 4800 rcu_read_lock(); 4801 do_each_thread(g, p) { 4802 /* 4803 * reset the NMI-timeout, listing all files on a slow 4804 * console might take a lot of time: 4805 */ 4806 touch_nmi_watchdog(); 4807 if (!state_filter || (p->state & state_filter)) 4808 sched_show_task(p); 4809 } while_each_thread(g, p); 4810 4811 touch_all_softlockup_watchdogs(); 4812 4813#ifdef CONFIG_SCHED_DEBUG 4814 sysrq_sched_debug_show(); 4815#endif 4816 rcu_read_unlock(); 4817 /* 4818 * Only show locks if all tasks are dumped: 4819 */ 4820 if (!state_filter) 4821 debug_show_all_locks(); 4822} 4823 4824void __cpuinit init_idle_bootup_task(struct task_struct *idle) 4825{ 4826 idle->sched_class = &idle_sched_class; 4827} 4828 4829/** 4830 * init_idle - set up an idle thread for a given CPU 4831 * @idle: task in question 4832 * @cpu: cpu the idle task belongs to 4833 * 4834 * NOTE: this function does not set the idle thread's NEED_RESCHED 4835 * flag, to make booting more robust. 4836 */ 4837void __cpuinit init_idle(struct task_struct *idle, int cpu) 4838{ 4839 struct rq *rq = cpu_rq(cpu); 4840 unsigned long flags; 4841 4842 raw_spin_lock_irqsave(&rq->lock, flags); 4843 4844 __sched_fork(idle); 4845 idle->state = TASK_RUNNING; 4846 idle->se.exec_start = sched_clock(); 4847 4848 do_set_cpus_allowed(idle, cpumask_of(cpu)); 4849 /* 4850 * We're having a chicken and egg problem, even though we are 4851 * holding rq->lock, the cpu isn't yet set to this cpu so the 4852 * lockdep check in task_group() will fail. 4853 * 4854 * Similar case to sched_fork(). / Alternatively we could 4855 * use task_rq_lock() here and obtain the other rq->lock. 4856 * 4857 * Silence PROVE_RCU 4858 */ 4859 rcu_read_lock(); 4860 __set_task_cpu(idle, cpu); 4861 rcu_read_unlock(); 4862 4863 rq->curr = rq->idle = idle; 4864#if defined(CONFIG_SMP) 4865 idle->on_cpu = 1; 4866#endif 4867 raw_spin_unlock_irqrestore(&rq->lock, flags); 4868 4869 /* Set the preempt count _outside_ the spinlocks! */ 4870 task_thread_info(idle)->preempt_count = 0; 4871 4872 /* 4873 * The idle tasks have their own, simple scheduling class: 4874 */ 4875 idle->sched_class = &idle_sched_class; 4876 ftrace_graph_init_idle_task(idle, cpu); 4877#if defined(CONFIG_SMP) 4878 sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu); 4879#endif 4880} 4881 4882#ifdef CONFIG_SMP 4883void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) 4884{ 4885 if (p->sched_class && p->sched_class->set_cpus_allowed) 4886 p->sched_class->set_cpus_allowed(p, new_mask); 4887 4888 cpumask_copy(&p->cpus_allowed, new_mask); 4889 p->rt.nr_cpus_allowed = cpumask_weight(new_mask); 4890} 4891 4892/* 4893 * This is how migration works: 4894 * 4895 * 1) we invoke migration_cpu_stop() on the target CPU using 4896 * stop_one_cpu(). 4897 * 2) stopper starts to run (implicitly forcing the migrated thread 4898 * off the CPU) 4899 * 3) it checks whether the migrated task is still in the wrong runqueue. 4900 * 4) if it's in the wrong runqueue then the migration thread removes 4901 * it and puts it into the right queue. 4902 * 5) stopper completes and stop_one_cpu() returns and the migration 4903 * is done. 4904 */ 4905 4906/* 4907 * Change a given task's CPU affinity. Migrate the thread to a 4908 * proper CPU and schedule it away if the CPU it's executing on 4909 * is removed from the allowed bitmask. 4910 * 4911 * NOTE: the caller must have a valid reference to the task, the 4912 * task must not exit() & deallocate itself prematurely. The 4913 * call is not atomic; no spinlocks may be held. 4914 */ 4915int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) 4916{ 4917 unsigned long flags; 4918 struct rq *rq; 4919 unsigned int dest_cpu; 4920 int ret = 0; 4921 4922 rq = task_rq_lock(p, &flags); 4923 4924 if (cpumask_equal(&p->cpus_allowed, new_mask)) 4925 goto out; 4926 4927 if (!cpumask_intersects(new_mask, cpu_active_mask)) { 4928 ret = -EINVAL; 4929 goto out; 4930 } 4931 4932 if (unlikely((p->flags & PF_THREAD_BOUND) && p != current)) { 4933 ret = -EINVAL; 4934 goto out; 4935 } 4936 4937 do_set_cpus_allowed(p, new_mask); 4938 4939 /* Can the task run on the task's current CPU? If so, we're done */ 4940 if (cpumask_test_cpu(task_cpu(p), new_mask)) 4941 goto out; 4942 4943 dest_cpu = cpumask_any_and(cpu_active_mask, new_mask); 4944 if (p->on_rq) { 4945 struct migration_arg arg = { p, dest_cpu }; 4946 /* Need help from migration thread: drop lock and wait. */ 4947 task_rq_unlock(rq, p, &flags); 4948 stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg); 4949 tlb_migrate_finish(p->mm); 4950 return 0; 4951 } 4952out: 4953 task_rq_unlock(rq, p, &flags); 4954 4955 return ret; 4956} 4957EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr); 4958 4959/* 4960 * Move (not current) task off this cpu, onto dest cpu. We're doing 4961 * this because either it can't run here any more (set_cpus_allowed() 4962 * away from this CPU, or CPU going down), or because we're 4963 * attempting to rebalance this task on exec (sched_exec). 4964 * 4965 * So we race with normal scheduler movements, but that's OK, as long 4966 * as the task is no longer on this CPU. 4967 * 4968 * Returns non-zero if task was successfully migrated. 4969 */ 4970static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) 4971{ 4972 struct rq *rq_dest, *rq_src; 4973 int ret = 0; 4974 4975 if (unlikely(!cpu_active(dest_cpu))) 4976 return ret; 4977 4978 rq_src = cpu_rq(src_cpu); 4979 rq_dest = cpu_rq(dest_cpu); 4980 4981 raw_spin_lock(&p->pi_lock); 4982 double_rq_lock(rq_src, rq_dest); 4983 /* Already moved. */ 4984 if (task_cpu(p) != src_cpu) 4985 goto done; 4986 /* Affinity changed (again). */ 4987 if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) 4988 goto fail; 4989 4990 /* 4991 * If we're not on a rq, the next wake-up will ensure we're 4992 * placed properly. 4993 */ 4994 if (p->on_rq) { 4995 dequeue_task(rq_src, p, 0); 4996 set_task_cpu(p, dest_cpu); 4997 enqueue_task(rq_dest, p, 0); 4998 check_preempt_curr(rq_dest, p, 0); 4999 } 5000done: 5001 ret = 1; 5002fail: 5003 double_rq_unlock(rq_src, rq_dest); 5004 raw_spin_unlock(&p->pi_lock); 5005 return ret; 5006} 5007 5008/* 5009 * migration_cpu_stop - this will be executed by a highprio stopper thread 5010 * and performs thread migration by bumping thread off CPU then 5011 * 'pushing' onto another runqueue. 5012 */ 5013static int migration_cpu_stop(void *data) 5014{ 5015 struct migration_arg *arg = data; 5016 5017 /* 5018 * The original target cpu might have gone down and we might 5019 * be on another cpu but it doesn't matter. 5020 */ 5021 local_irq_disable(); 5022 __migrate_task(arg->task, raw_smp_processor_id(), arg->dest_cpu); 5023 local_irq_enable(); 5024 return 0; 5025} 5026 5027#ifdef CONFIG_HOTPLUG_CPU 5028 5029/* 5030 * Ensures that the idle task is using init_mm right before its cpu goes 5031 * offline. 5032 */ 5033void idle_task_exit(void) 5034{ 5035 struct mm_struct *mm = current->active_mm; 5036 5037 BUG_ON(cpu_online(smp_processor_id())); 5038 5039 if (mm != &init_mm) 5040 switch_mm(mm, &init_mm, current); 5041 mmdrop(mm); 5042} 5043 5044/* 5045 * While a dead CPU has no uninterruptible tasks queued at this point, 5046 * it might still have a nonzero ->nr_uninterruptible counter, because 5047 * for performance reasons the counter is not stricly tracking tasks to 5048 * their home CPUs. So we just add the counter to another CPU's counter, 5049 * to keep the global sum constant after CPU-down: 5050 */ 5051static void migrate_nr_uninterruptible(struct rq *rq_src) 5052{ 5053 struct rq *rq_dest = cpu_rq(cpumask_any(cpu_active_mask)); 5054 5055 rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible; 5056 rq_src->nr_uninterruptible = 0; 5057} 5058 5059/* 5060 * remove the tasks which were accounted by rq from calc_load_tasks. 5061 */ 5062static void calc_global_load_remove(struct rq *rq) 5063{ 5064 atomic_long_sub(rq->calc_load_active, &calc_load_tasks); 5065 rq->calc_load_active = 0; 5066} 5067 5068/* 5069 * Migrate all tasks from the rq, sleeping tasks will be migrated by 5070 * try_to_wake_up()->select_task_rq(). 5071 * 5072 * Called with rq->lock held even though we'er in stop_machine() and 5073 * there's no concurrency possible, we hold the required locks anyway 5074 * because of lock validation efforts. 5075 */ 5076static void migrate_tasks(unsigned int dead_cpu) 5077{ 5078 struct rq *rq = cpu_rq(dead_cpu); 5079 struct task_struct *next, *stop = rq->stop; 5080 int dest_cpu; 5081 5082 /* 5083 * Fudge the rq selection such that the below task selection loop 5084 * doesn't get stuck on the currently eligible stop task. 5085 * 5086 * We're currently inside stop_machine() and the rq is either stuck 5087 * in the stop_machine_cpu_stop() loop, or we're executing this code, 5088 * either way we should never end up calling schedule() until we're 5089 * done here. 5090 */ 5091 rq->stop = NULL; 5092 5093 /* Ensure any throttled groups are reachable by pick_next_task */ 5094 unthrottle_offline_cfs_rqs(rq); 5095 5096 for ( ; ; ) { 5097 /* 5098 * There's this thread running, bail when that's the only 5099 * remaining thread. 5100 */ 5101 if (rq->nr_running == 1) 5102 break; 5103 5104 next = pick_next_task(rq); 5105 BUG_ON(!next); 5106 next->sched_class->put_prev_task(rq, next); 5107 5108 /* Find suitable destination for @next, with force if needed. */ 5109 dest_cpu = select_fallback_rq(dead_cpu, next); 5110 raw_spin_unlock(&rq->lock); 5111 5112 __migrate_task(next, dead_cpu, dest_cpu); 5113 5114 raw_spin_lock(&rq->lock); 5115 } 5116 5117 rq->stop = stop; 5118} 5119 5120#endif /* CONFIG_HOTPLUG_CPU */ 5121 5122#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL) 5123 5124static struct ctl_table sd_ctl_dir[] = { 5125 { 5126 .procname = "sched_domain", 5127 .mode = 0555, 5128 }, 5129 {} 5130}; 5131 5132static struct ctl_table sd_ctl_root[] = { 5133 { 5134 .procname = "kernel", 5135 .mode = 0555, 5136 .child = sd_ctl_dir, 5137 }, 5138 {} 5139}; 5140 5141static struct ctl_table *sd_alloc_ctl_entry(int n) 5142{ 5143 struct ctl_table *entry = 5144 kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL); 5145 5146 return entry; 5147} 5148 5149static void sd_free_ctl_entry(struct ctl_table **tablep) 5150{ 5151 struct ctl_table *entry; 5152 5153 /* 5154 * In the intermediate directories, both the child directory and 5155 * procname are dynamically allocated and could fail but the mode 5156 * will always be set. In the lowest directory the names are 5157 * static strings and all have proc handlers. 5158 */ 5159 for (entry = *tablep; entry->mode; entry++) { 5160 if (entry->child) 5161 sd_free_ctl_entry(&entry->child); 5162 if (entry->proc_handler == NULL) 5163 kfree(entry->procname); 5164 } 5165 5166 kfree(*tablep); 5167 *tablep = NULL; 5168} 5169 5170static void 5171set_table_entry(struct ctl_table *entry, 5172 const char *procname, void *data, int maxlen, 5173 umode_t mode, proc_handler *proc_handler) 5174{ 5175 entry->procname = procname; 5176 entry->data = data; 5177 entry->maxlen = maxlen; 5178 entry->mode = mode; 5179 entry->proc_handler = proc_handler; 5180} 5181 5182static struct ctl_table * 5183sd_alloc_ctl_domain_table(struct sched_domain *sd) 5184{ 5185 struct ctl_table *table = sd_alloc_ctl_entry(13); 5186 5187 if (table == NULL) 5188 return NULL; 5189 5190 set_table_entry(&table[0], "min_interval", &sd->min_interval, 5191 sizeof(long), 0644, proc_doulongvec_minmax); 5192 set_table_entry(&table[1], "max_interval", &sd->max_interval, 5193 sizeof(long), 0644, proc_doulongvec_minmax); 5194 set_table_entry(&table[2], "busy_idx", &sd->busy_idx, 5195 sizeof(int), 0644, proc_dointvec_minmax); 5196 set_table_entry(&table[3], "idle_idx", &sd->idle_idx, 5197 sizeof(int), 0644, proc_dointvec_minmax); 5198 set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx, 5199 sizeof(int), 0644, proc_dointvec_minmax); 5200 set_table_entry(&table[5], "wake_idx", &sd->wake_idx, 5201 sizeof(int), 0644, proc_dointvec_minmax); 5202 set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx, 5203 sizeof(int), 0644, proc_dointvec_minmax); 5204 set_table_entry(&table[7], "busy_factor", &sd->busy_factor, 5205 sizeof(int), 0644, proc_dointvec_minmax); 5206 set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct, 5207 sizeof(int), 0644, proc_dointvec_minmax); 5208 set_table_entry(&table[9], "cache_nice_tries", 5209 &sd->cache_nice_tries, 5210 sizeof(int), 0644, proc_dointvec_minmax); 5211 set_table_entry(&table[10], "flags", &sd->flags, 5212 sizeof(int), 0644, proc_dointvec_minmax); 5213 set_table_entry(&table[11], "name", sd->name, 5214 CORENAME_MAX_SIZE, 0444, proc_dostring); 5215 /* &table[12] is terminator */ 5216 5217 return table; 5218} 5219 5220static ctl_table *sd_alloc_ctl_cpu_table(int cpu) 5221{ 5222 struct ctl_table *entry, *table; 5223 struct sched_domain *sd; 5224 int domain_num = 0, i; 5225 char buf[32]; 5226 5227 for_each_domain(cpu, sd) 5228 domain_num++; 5229 entry = table = sd_alloc_ctl_entry(domain_num + 1); 5230 if (table == NULL) 5231 return NULL; 5232 5233 i = 0; 5234 for_each_domain(cpu, sd) { 5235 snprintf(buf, 32, "domain%d", i); 5236 entry->procname = kstrdup(buf, GFP_KERNEL); 5237 entry->mode = 0555; 5238 entry->child = sd_alloc_ctl_domain_table(sd); 5239 entry++; 5240 i++; 5241 } 5242 return table; 5243} 5244 5245static struct ctl_table_header *sd_sysctl_header; 5246static void register_sched_domain_sysctl(void) 5247{ 5248 int i, cpu_num = num_possible_cpus(); 5249 struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1); 5250 char buf[32]; 5251 5252 WARN_ON(sd_ctl_dir[0].child); 5253 sd_ctl_dir[0].child = entry; 5254 5255 if (entry == NULL) 5256 return; 5257 5258 for_each_possible_cpu(i) { 5259 snprintf(buf, 32, "cpu%d", i); 5260 entry->procname = kstrdup(buf, GFP_KERNEL); 5261 entry->mode = 0555; 5262 entry->child = sd_alloc_ctl_cpu_table(i); 5263 entry++; 5264 } 5265 5266 WARN_ON(sd_sysctl_header); 5267 sd_sysctl_header = register_sysctl_table(sd_ctl_root); 5268} 5269 5270/* may be called multiple times per register */ 5271static void unregister_sched_domain_sysctl(void) 5272{ 5273 if (sd_sysctl_header) 5274 unregister_sysctl_table(sd_sysctl_header); 5275 sd_sysctl_header = NULL; 5276 if (sd_ctl_dir[0].child) 5277 sd_free_ctl_entry(&sd_ctl_dir[0].child); 5278} 5279#else 5280static void register_sched_domain_sysctl(void) 5281{ 5282} 5283static void unregister_sched_domain_sysctl(void) 5284{ 5285} 5286#endif 5287 5288static void set_rq_online(struct rq *rq) 5289{ 5290 if (!rq->online) { 5291 const struct sched_class *class; 5292 5293 cpumask_set_cpu(rq->cpu, rq->rd->online); 5294 rq->online = 1; 5295 5296 for_each_class(class) { 5297 if (class->rq_online) 5298 class->rq_online(rq); 5299 } 5300 } 5301} 5302 5303static void set_rq_offline(struct rq *rq) 5304{ 5305 if (rq->online) { 5306 const struct sched_class *class; 5307 5308 for_each_class(class) { 5309 if (class->rq_offline) 5310 class->rq_offline(rq); 5311 } 5312 5313 cpumask_clear_cpu(rq->cpu, rq->rd->online); 5314 rq->online = 0; 5315 } 5316} 5317 5318/* 5319 * migration_call - callback that gets triggered when a CPU is added. 5320 * Here we can start up the necessary migration thread for the new CPU. 5321 */ 5322static int __cpuinit 5323migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) 5324{ 5325 int cpu = (long)hcpu; 5326 unsigned long flags; 5327 struct rq *rq = cpu_rq(cpu); 5328 5329 switch (action & ~CPU_TASKS_FROZEN) { 5330 5331 case CPU_UP_PREPARE: 5332 rq->calc_load_update = calc_load_update; 5333 break; 5334 5335 case CPU_ONLINE: 5336 /* Update our root-domain */ 5337 raw_spin_lock_irqsave(&rq->lock, flags); 5338 if (rq->rd) { 5339 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); 5340 5341 set_rq_online(rq); 5342 } 5343 raw_spin_unlock_irqrestore(&rq->lock, flags); 5344 break; 5345 5346#ifdef CONFIG_HOTPLUG_CPU 5347 case CPU_DYING: 5348 sched_ttwu_pending(); 5349 /* Update our root-domain */ 5350 raw_spin_lock_irqsave(&rq->lock, flags); 5351 if (rq->rd) { 5352 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); 5353 set_rq_offline(rq); 5354 } 5355 migrate_tasks(cpu); 5356 BUG_ON(rq->nr_running != 1); /* the migration thread */ 5357 raw_spin_unlock_irqrestore(&rq->lock, flags); 5358 5359 migrate_nr_uninterruptible(rq); 5360 calc_global_load_remove(rq); 5361 break; 5362#endif 5363 } 5364 5365 update_max_interval(); 5366 5367 return NOTIFY_OK; 5368} 5369 5370/* 5371 * Register at high priority so that task migration (migrate_all_tasks) 5372 * happens before everything else. This has to be lower priority than 5373 * the notifier in the perf_event subsystem, though. 5374 */ 5375static struct notifier_block __cpuinitdata migration_notifier = { 5376 .notifier_call = migration_call, 5377 .priority = CPU_PRI_MIGRATION, 5378}; 5379 5380static int __cpuinit sched_cpu_active(struct notifier_block *nfb, 5381 unsigned long action, void *hcpu) 5382{ 5383 switch (action & ~CPU_TASKS_FROZEN) { 5384 case CPU_ONLINE: 5385 case CPU_DOWN_FAILED: 5386 set_cpu_active((long)hcpu, true); 5387 return NOTIFY_OK; 5388 default: 5389 return NOTIFY_DONE; 5390 } 5391} 5392 5393static int __cpuinit sched_cpu_inactive(struct notifier_block *nfb, 5394 unsigned long action, void *hcpu) 5395{ 5396 switch (action & ~CPU_TASKS_FROZEN) { 5397 case CPU_DOWN_PREPARE: 5398 set_cpu_active((long)hcpu, false); 5399 return NOTIFY_OK; 5400 default: 5401 return NOTIFY_DONE; 5402 } 5403} 5404 5405static int __init migration_init(void) 5406{ 5407 void *cpu = (void *)(long)smp_processor_id(); 5408 int err; 5409 5410 /* Initialize migration for the boot CPU */ 5411 err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); 5412 BUG_ON(err == NOTIFY_BAD); 5413 migration_call(&migration_notifier, CPU_ONLINE, cpu); 5414 register_cpu_notifier(&migration_notifier); 5415 5416 /* Register cpu active notifiers */ 5417 cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE); 5418 cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE); 5419 5420 return 0; 5421} 5422early_initcall(migration_init); 5423#endif 5424 5425#ifdef CONFIG_SMP 5426 5427static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */ 5428 5429#ifdef CONFIG_SCHED_DEBUG 5430 5431static __read_mostly int sched_domain_debug_enabled; 5432 5433static int __init sched_domain_debug_setup(char *str) 5434{ 5435 sched_domain_debug_enabled = 1; 5436 5437 return 0; 5438} 5439early_param("sched_debug", sched_domain_debug_setup); 5440 5441static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, 5442 struct cpumask *groupmask) 5443{ 5444 struct sched_group *group = sd->groups; 5445 char str[256]; 5446 5447 cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd)); 5448 cpumask_clear(groupmask); 5449 5450 printk(KERN_DEBUG "%*s domain %d: ", level, "", level); 5451 5452 if (!(sd->flags & SD_LOAD_BALANCE)) { 5453 printk("does not load-balance\n"); 5454 if (sd->parent) 5455 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain" 5456 " has parent"); 5457 return -1; 5458 } 5459 5460 printk(KERN_CONT "span %s level %s\n", str, sd->name); 5461 5462 if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) { 5463 printk(KERN_ERR "ERROR: domain->span does not contain " 5464 "CPU%d\n", cpu); 5465 } 5466 if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) { 5467 printk(KERN_ERR "ERROR: domain->groups does not contain" 5468 " CPU%d\n", cpu); 5469 } 5470 5471 printk(KERN_DEBUG "%*s groups:", level + 1, ""); 5472 do { 5473 if (!group) { 5474 printk("\n"); 5475 printk(KERN_ERR "ERROR: group is NULL\n"); 5476 break; 5477 } 5478 5479 if (!group->sgp->power) { 5480 printk(KERN_CONT "\n"); 5481 printk(KERN_ERR "ERROR: domain->cpu_power not " 5482 "set\n"); 5483 break; 5484 } 5485 5486 if (!cpumask_weight(sched_group_cpus(group))) { 5487 printk(KERN_CONT "\n"); 5488 printk(KERN_ERR "ERROR: empty group\n"); 5489 break; 5490 } 5491 5492 if (cpumask_intersects(groupmask, sched_group_cpus(group))) { 5493 printk(KERN_CONT "\n"); 5494 printk(KERN_ERR "ERROR: repeated CPUs\n"); 5495 break; 5496 } 5497 5498 cpumask_or(groupmask, groupmask, sched_group_cpus(group)); 5499 5500 cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group)); 5501 5502 printk(KERN_CONT " %s", str); 5503 if (group->sgp->power != SCHED_POWER_SCALE) { 5504 printk(KERN_CONT " (cpu_power = %d)", 5505 group->sgp->power); 5506 } 5507 5508 group = group->next; 5509 } while (group != sd->groups); 5510 printk(KERN_CONT "\n"); 5511 5512 if (!cpumask_equal(sched_domain_span(sd), groupmask)) 5513 printk(KERN_ERR "ERROR: groups don't span domain->span\n"); 5514 5515 if (sd->parent && 5516 !cpumask_subset(groupmask, sched_domain_span(sd->parent))) 5517 printk(KERN_ERR "ERROR: parent span is not a superset " 5518 "of domain->span\n"); 5519 return 0; 5520} 5521 5522static void sched_domain_debug(struct sched_domain *sd, int cpu) 5523{ 5524 int level = 0; 5525 5526 if (!sched_domain_debug_enabled) 5527 return; 5528 5529 if (!sd) { 5530 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); 5531 return; 5532 } 5533 5534 printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); 5535 5536 for (;;) { 5537 if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask)) 5538 break; 5539 level++; 5540 sd = sd->parent; 5541 if (!sd) 5542 break; 5543 } 5544} 5545#else /* !CONFIG_SCHED_DEBUG */ 5546# define sched_domain_debug(sd, cpu) do { } while (0) 5547#endif /* CONFIG_SCHED_DEBUG */ 5548 5549static int sd_degenerate(struct sched_domain *sd) 5550{ 5551 if (cpumask_weight(sched_domain_span(sd)) == 1) 5552 return 1; 5553 5554 /* Following flags need at least 2 groups */ 5555 if (sd->flags & (SD_LOAD_BALANCE | 5556 SD_BALANCE_NEWIDLE | 5557 SD_BALANCE_FORK | 5558 SD_BALANCE_EXEC | 5559 SD_SHARE_CPUPOWER | 5560 SD_SHARE_PKG_RESOURCES)) { 5561 if (sd->groups != sd->groups->next) 5562 return 0; 5563 } 5564 5565 /* Following flags don't use groups */ 5566 if (sd->flags & (SD_WAKE_AFFINE)) 5567 return 0; 5568 5569 return 1; 5570} 5571 5572static int 5573sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) 5574{ 5575 unsigned long cflags = sd->flags, pflags = parent->flags; 5576 5577 if (sd_degenerate(parent)) 5578 return 1; 5579 5580 if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent))) 5581 return 0; 5582 5583 /* Flags needing groups don't count if only 1 group in parent */ 5584 if (parent->groups == parent->groups->next) { 5585 pflags &= ~(SD_LOAD_BALANCE | 5586 SD_BALANCE_NEWIDLE | 5587 SD_BALANCE_FORK | 5588 SD_BALANCE_EXEC | 5589 SD_SHARE_CPUPOWER | 5590 SD_SHARE_PKG_RESOURCES); 5591 if (nr_node_ids == 1) 5592 pflags &= ~SD_SERIALIZE; 5593 } 5594 if (~cflags & pflags) 5595 return 0; 5596 5597 return 1; 5598} 5599 5600static void free_rootdomain(struct rcu_head *rcu) 5601{ 5602 struct root_domain *rd = container_of(rcu, struct root_domain, rcu); 5603 5604 cpupri_cleanup(&rd->cpupri); 5605 free_cpumask_var(rd->rto_mask); 5606 free_cpumask_var(rd->online); 5607 free_cpumask_var(rd->span); 5608 kfree(rd); 5609} 5610 5611static void rq_attach_root(struct rq *rq, struct root_domain *rd) 5612{ 5613 struct root_domain *old_rd = NULL; 5614 unsigned long flags; 5615 5616 raw_spin_lock_irqsave(&rq->lock, flags); 5617 5618 if (rq->rd) { 5619 old_rd = rq->rd; 5620 5621 if (cpumask_test_cpu(rq->cpu, old_rd->online)) 5622 set_rq_offline(rq); 5623 5624 cpumask_clear_cpu(rq->cpu, old_rd->span); 5625 5626 /* 5627 * If we dont want to free the old_rt yet then 5628 * set old_rd to NULL to skip the freeing later 5629 * in this function: 5630 */ 5631 if (!atomic_dec_and_test(&old_rd->refcount)) 5632 old_rd = NULL; 5633 } 5634 5635 atomic_inc(&rd->refcount); 5636 rq->rd = rd; 5637 5638 cpumask_set_cpu(rq->cpu, rd->span); 5639 if (cpumask_test_cpu(rq->cpu, cpu_active_mask)) 5640 set_rq_online(rq); 5641 5642 raw_spin_unlock_irqrestore(&rq->lock, flags); 5643 5644 if (old_rd) 5645 call_rcu_sched(&old_rd->rcu, free_rootdomain); 5646} 5647 5648static int init_rootdomain(struct root_domain *rd) 5649{ 5650 memset(rd, 0, sizeof(*rd)); 5651 5652 if (!alloc_cpumask_var(&rd->span, GFP_KERNEL)) 5653 goto out; 5654 if (!alloc_cpumask_var(&rd->online, GFP_KERNEL)) 5655 goto free_span; 5656 if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL)) 5657 goto free_online; 5658 5659 if (cpupri_init(&rd->cpupri) != 0) 5660 goto free_rto_mask; 5661 return 0; 5662 5663free_rto_mask: 5664 free_cpumask_var(rd->rto_mask); 5665free_online: 5666 free_cpumask_var(rd->online); 5667free_span: 5668 free_cpumask_var(rd->span); 5669out: 5670 return -ENOMEM; 5671} 5672 5673/* 5674 * By default the system creates a single root-domain with all cpus as 5675 * members (mimicking the global state we have today). 5676 */ 5677struct root_domain def_root_domain; 5678 5679static void init_defrootdomain(void) 5680{ 5681 init_rootdomain(&def_root_domain); 5682 5683 atomic_set(&def_root_domain.refcount, 1); 5684} 5685 5686static struct root_domain *alloc_rootdomain(void) 5687{ 5688 struct root_domain *rd; 5689 5690 rd = kmalloc(sizeof(*rd), GFP_KERNEL); 5691 if (!rd) 5692 return NULL; 5693 5694 if (init_rootdomain(rd) != 0) { 5695 kfree(rd); 5696 return NULL; 5697 } 5698 5699 return rd; 5700} 5701 5702static void free_sched_groups(struct sched_group *sg, int free_sgp) 5703{ 5704 struct sched_group *tmp, *first; 5705 5706 if (!sg) 5707 return; 5708 5709 first = sg; 5710 do { 5711 tmp = sg->next; 5712 5713 if (free_sgp && atomic_dec_and_test(&sg->sgp->ref)) 5714 kfree(sg->sgp); 5715 5716 kfree(sg); 5717 sg = tmp; 5718 } while (sg != first); 5719} 5720 5721static void free_sched_domain(struct rcu_head *rcu) 5722{ 5723 struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu); 5724 5725 /* 5726 * If its an overlapping domain it has private groups, iterate and 5727 * nuke them all. 5728 */ 5729 if (sd->flags & SD_OVERLAP) { 5730 free_sched_groups(sd->groups, 1); 5731 } else if (atomic_dec_and_test(&sd->groups->ref)) { 5732 kfree(sd->groups->sgp); 5733 kfree(sd->groups); 5734 } 5735 kfree(sd); 5736} 5737 5738static void destroy_sched_domain(struct sched_domain *sd, int cpu) 5739{ 5740 call_rcu(&sd->rcu, free_sched_domain); 5741} 5742 5743static void destroy_sched_domains(struct sched_domain *sd, int cpu) 5744{ 5745 for (; sd; sd = sd->parent) 5746 destroy_sched_domain(sd, cpu); 5747} 5748 5749/* 5750 * Keep a special pointer to the highest sched_domain that has 5751 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this 5752 * allows us to avoid some pointer chasing select_idle_sibling(). 5753 * 5754 * Also keep a unique ID per domain (we use the first cpu number in 5755 * the cpumask of the domain), this allows us to quickly tell if 5756 * two cpus are in the same cache domain, see ttwu_share_cache(). 5757 */ 5758DEFINE_PER_CPU(struct sched_domain *, sd_llc); 5759DEFINE_PER_CPU(int, sd_llc_id); 5760 5761static void update_top_cache_domain(int cpu) 5762{ 5763 struct sched_domain *sd; 5764 int id = cpu; 5765 5766 sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES); 5767 if (sd) 5768 id = cpumask_first(sched_domain_span(sd)); 5769 5770 rcu_assign_pointer(per_cpu(sd_llc, cpu), sd); 5771 per_cpu(sd_llc_id, cpu) = id; 5772} 5773 5774/* 5775 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must 5776 * hold the hotplug lock. 5777 */ 5778static void 5779cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) 5780{ 5781 struct rq *rq = cpu_rq(cpu); 5782 struct sched_domain *tmp; 5783 5784 /* Remove the sched domains which do not contribute to scheduling. */ 5785 for (tmp = sd; tmp; ) { 5786 struct sched_domain *parent = tmp->parent; 5787 if (!parent) 5788 break; 5789 5790 if (sd_parent_degenerate(tmp, parent)) { 5791 tmp->parent = parent->parent; 5792 if (parent->parent) 5793 parent->parent->child = tmp; 5794 destroy_sched_domain(parent, cpu); 5795 } else 5796 tmp = tmp->parent; 5797 } 5798 5799 if (sd && sd_degenerate(sd)) { 5800 tmp = sd; 5801 sd = sd->parent; 5802 destroy_sched_domain(tmp, cpu); 5803 if (sd) 5804 sd->child = NULL; 5805 } 5806 5807 sched_domain_debug(sd, cpu); 5808 5809 rq_attach_root(rq, rd); 5810 tmp = rq->sd; 5811 rcu_assign_pointer(rq->sd, sd); 5812 destroy_sched_domains(tmp, cpu); 5813 5814 update_top_cache_domain(cpu); 5815} 5816 5817/* cpus with isolated domains */ 5818static cpumask_var_t cpu_isolated_map; 5819 5820/* Setup the mask of cpus configured for isolated domains */ 5821static int __init isolated_cpu_setup(char *str) 5822{ 5823 alloc_bootmem_cpumask_var(&cpu_isolated_map); 5824 cpulist_parse(str, cpu_isolated_map); 5825 return 1; 5826} 5827 5828__setup("isolcpus=", isolated_cpu_setup); 5829 5830#ifdef CONFIG_NUMA 5831 5832/** 5833 * find_next_best_node - find the next node to include in a sched_domain 5834 * @node: node whose sched_domain we're building 5835 * @used_nodes: nodes already in the sched_domain 5836 * 5837 * Find the next node to include in a given scheduling domain. Simply 5838 * finds the closest node not already in the @used_nodes map. 5839 * 5840 * Should use nodemask_t. 5841 */ 5842static int find_next_best_node(int node, nodemask_t *used_nodes) 5843{ 5844 int i, n, val, min_val, best_node = -1; 5845 5846 min_val = INT_MAX; 5847 5848 for (i = 0; i < nr_node_ids; i++) { 5849 /* Start at @node */ 5850 n = (node + i) % nr_node_ids; 5851 5852 if (!nr_cpus_node(n)) 5853 continue; 5854 5855 /* Skip already used nodes */ 5856 if (node_isset(n, *used_nodes)) 5857 continue; 5858 5859 /* Simple min distance search */ 5860 val = node_distance(node, n); 5861 5862 if (val < min_val) { 5863 min_val = val; 5864 best_node = n; 5865 } 5866 } 5867 5868 if (best_node != -1) 5869 node_set(best_node, *used_nodes); 5870 return best_node; 5871} 5872 5873/** 5874 * sched_domain_node_span - get a cpumask for a node's sched_domain 5875 * @node: node whose cpumask we're constructing 5876 * @span: resulting cpumask 5877 * 5878 * Given a node, construct a good cpumask for its sched_domain to span. It 5879 * should be one that prevents unnecessary balancing, but also spreads tasks 5880 * out optimally. 5881 */ 5882static void sched_domain_node_span(int node, struct cpumask *span) 5883{ 5884 nodemask_t used_nodes; 5885 int i; 5886 5887 cpumask_clear(span); 5888 nodes_clear(used_nodes); 5889 5890 cpumask_or(span, span, cpumask_of_node(node)); 5891 node_set(node, used_nodes); 5892 5893 for (i = 1; i < SD_NODES_PER_DOMAIN; i++) { 5894 int next_node = find_next_best_node(node, &used_nodes); 5895 if (next_node < 0) 5896 break; 5897 cpumask_or(span, span, cpumask_of_node(next_node)); 5898 } 5899} 5900 5901static const struct cpumask *cpu_node_mask(int cpu) 5902{ 5903 lockdep_assert_held(&sched_domains_mutex); 5904 5905 sched_domain_node_span(cpu_to_node(cpu), sched_domains_tmpmask); 5906 5907 return sched_domains_tmpmask; 5908} 5909 5910static const struct cpumask *cpu_allnodes_mask(int cpu) 5911{ 5912 return cpu_possible_mask; 5913} 5914#endif /* CONFIG_NUMA */ 5915 5916static const struct cpumask *cpu_cpu_mask(int cpu) 5917{ 5918 return cpumask_of_node(cpu_to_node(cpu)); 5919} 5920 5921int sched_smt_power_savings = 0, sched_mc_power_savings = 0; 5922 5923struct sd_data { 5924 struct sched_domain **__percpu sd; 5925 struct sched_group **__percpu sg; 5926 struct sched_group_power **__percpu sgp; 5927}; 5928 5929struct s_data { 5930 struct sched_domain ** __percpu sd; 5931 struct root_domain *rd; 5932}; 5933 5934enum s_alloc { 5935 sa_rootdomain, 5936 sa_sd, 5937 sa_sd_storage, 5938 sa_none, 5939}; 5940 5941struct sched_domain_topology_level; 5942 5943typedef struct sched_domain *(*sched_domain_init_f)(struct sched_domain_topology_level *tl, int cpu); 5944typedef const struct cpumask *(*sched_domain_mask_f)(int cpu); 5945 5946#define SDTL_OVERLAP 0x01 5947 5948struct sched_domain_topology_level { 5949 sched_domain_init_f init; 5950 sched_domain_mask_f mask; 5951 int flags; 5952 struct sd_data data; 5953}; 5954 5955static int 5956build_overlap_sched_groups(struct sched_domain *sd, int cpu) 5957{ 5958 struct sched_group *first = NULL, *last = NULL, *groups = NULL, *sg; 5959 const struct cpumask *span = sched_domain_span(sd); 5960 struct cpumask *covered = sched_domains_tmpmask; 5961 struct sd_data *sdd = sd->private; 5962 struct sched_domain *child; 5963 int i; 5964 5965 cpumask_clear(covered); 5966 5967 for_each_cpu(i, span) { 5968 struct cpumask *sg_span; 5969 5970 if (cpumask_test_cpu(i, covered)) 5971 continue; 5972 5973 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), 5974 GFP_KERNEL, cpu_to_node(cpu)); 5975 5976 if (!sg) 5977 goto fail; 5978 5979 sg_span = sched_group_cpus(sg); 5980 5981 child = *per_cpu_ptr(sdd->sd, i); 5982 if (child->child) { 5983 child = child->child; 5984 cpumask_copy(sg_span, sched_domain_span(child)); 5985 } else 5986 cpumask_set_cpu(i, sg_span); 5987 5988 cpumask_or(covered, covered, sg_span); 5989 5990 sg->sgp = *per_cpu_ptr(sdd->sgp, cpumask_first(sg_span)); 5991 atomic_inc(&sg->sgp->ref); 5992 5993 if (cpumask_test_cpu(cpu, sg_span)) 5994 groups = sg; 5995 5996 if (!first) 5997 first = sg; 5998 if (last) 5999 last->next = sg; 6000 last = sg; 6001 last->next = first; 6002 } 6003 sd->groups = groups; 6004 6005 return 0; 6006 6007fail: 6008 free_sched_groups(first, 0); 6009 6010 return -ENOMEM; 6011} 6012 6013static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg) 6014{ 6015 struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu); 6016 struct sched_domain *child = sd->child; 6017 6018 if (child) 6019 cpu = cpumask_first(sched_domain_span(child)); 6020 6021 if (sg) { 6022 *sg = *per_cpu_ptr(sdd->sg, cpu); 6023 (*sg)->sgp = *per_cpu_ptr(sdd->sgp, cpu); 6024 atomic_set(&(*sg)->sgp->ref, 1); /* for claim_allocations */ 6025 } 6026 6027 return cpu; 6028} 6029 6030/* 6031 * build_sched_groups will build a circular linked list of the groups 6032 * covered by the given span, and will set each group's ->cpumask correctly, 6033 * and ->cpu_power to 0. 6034 * 6035 * Assumes the sched_domain tree is fully constructed 6036 */ 6037static int 6038build_sched_groups(struct sched_domain *sd, int cpu) 6039{ 6040 struct sched_group *first = NULL, *last = NULL; 6041 struct sd_data *sdd = sd->private; 6042 const struct cpumask *span = sched_domain_span(sd); 6043 struct cpumask *covered; 6044 int i; 6045 6046 get_group(cpu, sdd, &sd->groups); 6047 atomic_inc(&sd->groups->ref); 6048 6049 if (cpu != cpumask_first(sched_domain_span(sd))) 6050 return 0; 6051 6052 lockdep_assert_held(&sched_domains_mutex); 6053 covered = sched_domains_tmpmask; 6054 6055 cpumask_clear(covered); 6056 6057 for_each_cpu(i, span) { 6058 struct sched_group *sg; 6059 int group = get_group(i, sdd, &sg); 6060 int j; 6061 6062 if (cpumask_test_cpu(i, covered)) 6063 continue; 6064 6065 cpumask_clear(sched_group_cpus(sg)); 6066 sg->sgp->power = 0; 6067 6068 for_each_cpu(j, span) { 6069 if (get_group(j, sdd, NULL) != group) 6070 continue; 6071 6072 cpumask_set_cpu(j, covered); 6073 cpumask_set_cpu(j, sched_group_cpus(sg)); 6074 } 6075 6076 if (!first) 6077 first = sg; 6078 if (last) 6079 last->next = sg; 6080 last = sg; 6081 } 6082 last->next = first; 6083 6084 return 0; 6085} 6086 6087/* 6088 * Initialize sched groups cpu_power. 6089 * 6090 * cpu_power indicates the capacity of sched group, which is used while 6091 * distributing the load between different sched groups in a sched domain. 6092 * Typically cpu_power for all the groups in a sched domain will be same unless 6093 * there are asymmetries in the topology. If there are asymmetries, group 6094 * having more cpu_power will pickup more load compared to the group having 6095 * less cpu_power. 6096 */ 6097static void init_sched_groups_power(int cpu, struct sched_domain *sd) 6098{ 6099 struct sched_group *sg = sd->groups; 6100 6101 WARN_ON(!sd || !sg); 6102 6103 do { 6104 sg->group_weight = cpumask_weight(sched_group_cpus(sg)); 6105 sg = sg->next; 6106 } while (sg != sd->groups); 6107 6108 if (cpu != group_first_cpu(sg)) 6109 return; 6110 6111 update_group_power(sd, cpu); 6112 atomic_set(&sg->sgp->nr_busy_cpus, sg->group_weight); 6113} 6114 6115int __weak arch_sd_sibling_asym_packing(void) 6116{ 6117 return 0*SD_ASYM_PACKING; 6118} 6119 6120/* 6121 * Initializers for schedule domains 6122 * Non-inlined to reduce accumulated stack pressure in build_sched_domains() 6123 */ 6124 6125#ifdef CONFIG_SCHED_DEBUG 6126# define SD_INIT_NAME(sd, type) sd->name = #type 6127#else 6128# define SD_INIT_NAME(sd, type) do { } while (0) 6129#endif 6130 6131#define SD_INIT_FUNC(type) \ 6132static noinline struct sched_domain * \ 6133sd_init_##type(struct sched_domain_topology_level *tl, int cpu) \ 6134{ \ 6135 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); \ 6136 *sd = SD_##type##_INIT; \ 6137 SD_INIT_NAME(sd, type); \ 6138 sd->private = &tl->data; \ 6139 return sd; \ 6140} 6141 6142SD_INIT_FUNC(CPU) 6143#ifdef CONFIG_NUMA 6144 SD_INIT_FUNC(ALLNODES) 6145 SD_INIT_FUNC(NODE) 6146#endif 6147#ifdef CONFIG_SCHED_SMT 6148 SD_INIT_FUNC(SIBLING) 6149#endif 6150#ifdef CONFIG_SCHED_MC 6151 SD_INIT_FUNC(MC) 6152#endif 6153#ifdef CONFIG_SCHED_BOOK 6154 SD_INIT_FUNC(BOOK) 6155#endif 6156 6157static int default_relax_domain_level = -1; 6158int sched_domain_level_max; 6159 6160static int __init setup_relax_domain_level(char *str) 6161{ 6162 unsigned long val; 6163 6164 val = simple_strtoul(str, NULL, 0); 6165 if (val < sched_domain_level_max) 6166 default_relax_domain_level = val; 6167 6168 return 1; 6169} 6170__setup("relax_domain_level=", setup_relax_domain_level); 6171 6172static void set_domain_attribute(struct sched_domain *sd, 6173 struct sched_domain_attr *attr) 6174{ 6175 int request; 6176 6177 if (!attr || attr->relax_domain_level < 0) { 6178 if (default_relax_domain_level < 0) 6179 return; 6180 else 6181 request = default_relax_domain_level; 6182 } else 6183 request = attr->relax_domain_level; 6184 if (request < sd->level) { 6185 /* turn off idle balance on this domain */ 6186 sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); 6187 } else { 6188 /* turn on idle balance on this domain */ 6189 sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); 6190 } 6191} 6192 6193static void __sdt_free(const struct cpumask *cpu_map); 6194static int __sdt_alloc(const struct cpumask *cpu_map); 6195 6196static void __free_domain_allocs(struct s_data *d, enum s_alloc what, 6197 const struct cpumask *cpu_map) 6198{ 6199 switch (what) { 6200 case sa_rootdomain: 6201 if (!atomic_read(&d->rd->refcount)) 6202 free_rootdomain(&d->rd->rcu); /* fall through */ 6203 case sa_sd: 6204 free_percpu(d->sd); /* fall through */ 6205 case sa_sd_storage: 6206 __sdt_free(cpu_map); /* fall through */ 6207 case sa_none: 6208 break; 6209 } 6210} 6211 6212static enum s_alloc __visit_domain_allocation_hell(struct s_data *d, 6213 const struct cpumask *cpu_map) 6214{ 6215 memset(d, 0, sizeof(*d)); 6216 6217 if (__sdt_alloc(cpu_map)) 6218 return sa_sd_storage; 6219 d->sd = alloc_percpu(struct sched_domain *); 6220 if (!d->sd) 6221 return sa_sd_storage; 6222 d->rd = alloc_rootdomain(); 6223 if (!d->rd) 6224 return sa_sd; 6225 return sa_rootdomain; 6226} 6227 6228/* 6229 * NULL the sd_data elements we've used to build the sched_domain and 6230 * sched_group structure so that the subsequent __free_domain_allocs() 6231 * will not free the data we're using. 6232 */ 6233static void claim_allocations(int cpu, struct sched_domain *sd) 6234{ 6235 struct sd_data *sdd = sd->private; 6236 6237 WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd); 6238 *per_cpu_ptr(sdd->sd, cpu) = NULL; 6239 6240 if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref)) 6241 *per_cpu_ptr(sdd->sg, cpu) = NULL; 6242 6243 if (atomic_read(&(*per_cpu_ptr(sdd->sgp, cpu))->ref)) 6244 *per_cpu_ptr(sdd->sgp, cpu) = NULL; 6245} 6246 6247#ifdef CONFIG_SCHED_SMT 6248static const struct cpumask *cpu_smt_mask(int cpu) 6249{ 6250 return topology_thread_cpumask(cpu); 6251} 6252#endif 6253 6254/* 6255 * Topology list, bottom-up. 6256 */ 6257static struct sched_domain_topology_level default_topology[] = { 6258#ifdef CONFIG_SCHED_SMT 6259 { sd_init_SIBLING, cpu_smt_mask, }, 6260#endif 6261#ifdef CONFIG_SCHED_MC 6262 { sd_init_MC, cpu_coregroup_mask, }, 6263#endif 6264#ifdef CONFIG_SCHED_BOOK 6265 { sd_init_BOOK, cpu_book_mask, }, 6266#endif 6267 { sd_init_CPU, cpu_cpu_mask, }, 6268#ifdef CONFIG_NUMA 6269 { sd_init_NODE, cpu_node_mask, SDTL_OVERLAP, }, 6270 { sd_init_ALLNODES, cpu_allnodes_mask, }, 6271#endif 6272 { NULL, }, 6273}; 6274 6275static struct sched_domain_topology_level *sched_domain_topology = default_topology; 6276 6277static int __sdt_alloc(const struct cpumask *cpu_map) 6278{ 6279 struct sched_domain_topology_level *tl; 6280 int j; 6281 6282 for (tl = sched_domain_topology; tl->init; tl++) { 6283 struct sd_data *sdd = &tl->data; 6284 6285 sdd->sd = alloc_percpu(struct sched_domain *); 6286 if (!sdd->sd) 6287 return -ENOMEM; 6288 6289 sdd->sg = alloc_percpu(struct sched_group *); 6290 if (!sdd->sg) 6291 return -ENOMEM; 6292 6293 sdd->sgp = alloc_percpu(struct sched_group_power *); 6294 if (!sdd->sgp) 6295 return -ENOMEM; 6296 6297 for_each_cpu(j, cpu_map) { 6298 struct sched_domain *sd; 6299 struct sched_group *sg; 6300 struct sched_group_power *sgp; 6301 6302 sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(), 6303 GFP_KERNEL, cpu_to_node(j)); 6304 if (!sd) 6305 return -ENOMEM; 6306 6307 *per_cpu_ptr(sdd->sd, j) = sd; 6308 6309 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), 6310 GFP_KERNEL, cpu_to_node(j)); 6311 if (!sg) 6312 return -ENOMEM; 6313 6314 *per_cpu_ptr(sdd->sg, j) = sg; 6315 6316 sgp = kzalloc_node(sizeof(struct sched_group_power), 6317 GFP_KERNEL, cpu_to_node(j)); 6318 if (!sgp) 6319 return -ENOMEM; 6320 6321 *per_cpu_ptr(sdd->sgp, j) = sgp; 6322 } 6323 } 6324 6325 return 0; 6326} 6327 6328static void __sdt_free(const struct cpumask *cpu_map) 6329{ 6330 struct sched_domain_topology_level *tl; 6331 int j; 6332 6333 for (tl = sched_domain_topology; tl->init; tl++) { 6334 struct sd_data *sdd = &tl->data; 6335 6336 for_each_cpu(j, cpu_map) { 6337 struct sched_domain *sd = *per_cpu_ptr(sdd->sd, j); 6338 if (sd && (sd->flags & SD_OVERLAP)) 6339 free_sched_groups(sd->groups, 0); 6340 kfree(*per_cpu_ptr(sdd->sd, j)); 6341 kfree(*per_cpu_ptr(sdd->sg, j)); 6342 kfree(*per_cpu_ptr(sdd->sgp, j)); 6343 } 6344 free_percpu(sdd->sd); 6345 free_percpu(sdd->sg); 6346 free_percpu(sdd->sgp); 6347 } 6348} 6349 6350struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl, 6351 struct s_data *d, const struct cpumask *cpu_map, 6352 struct sched_domain_attr *attr, struct sched_domain *child, 6353 int cpu) 6354{ 6355 struct sched_domain *sd = tl->init(tl, cpu); 6356 if (!sd) 6357 return child; 6358 6359 set_domain_attribute(sd, attr); 6360 cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu)); 6361 if (child) { 6362 sd->level = child->level + 1; 6363 sched_domain_level_max = max(sched_domain_level_max, sd->level); 6364 child->parent = sd; 6365 } 6366 sd->child = child; 6367 6368 return sd; 6369} 6370 6371/* 6372 * Build sched domains for a given set of cpus and attach the sched domains 6373 * to the individual cpus 6374 */ 6375static int build_sched_domains(const struct cpumask *cpu_map, 6376 struct sched_domain_attr *attr) 6377{ 6378 enum s_alloc alloc_state = sa_none; 6379 struct sched_domain *sd; 6380 struct s_data d; 6381 int i, ret = -ENOMEM; 6382 6383 alloc_state = __visit_domain_allocation_hell(&d, cpu_map); 6384 if (alloc_state != sa_rootdomain) 6385 goto error; 6386 6387 /* Set up domains for cpus specified by the cpu_map. */ 6388 for_each_cpu(i, cpu_map) { 6389 struct sched_domain_topology_level *tl; 6390 6391 sd = NULL; 6392 for (tl = sched_domain_topology; tl->init; tl++) { 6393 sd = build_sched_domain(tl, &d, cpu_map, attr, sd, i); 6394 if (tl->flags & SDTL_OVERLAP || sched_feat(FORCE_SD_OVERLAP)) 6395 sd->flags |= SD_OVERLAP; 6396 if (cpumask_equal(cpu_map, sched_domain_span(sd))) 6397 break; 6398 } 6399 6400 while (sd->child) 6401 sd = sd->child; 6402 6403 *per_cpu_ptr(d.sd, i) = sd; 6404 } 6405 6406 /* Build the groups for the domains */ 6407 for_each_cpu(i, cpu_map) { 6408 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { 6409 sd->span_weight = cpumask_weight(sched_domain_span(sd)); 6410 if (sd->flags & SD_OVERLAP) { 6411 if (build_overlap_sched_groups(sd, i)) 6412 goto error; 6413 } else { 6414 if (build_sched_groups(sd, i)) 6415 goto error; 6416 } 6417 } 6418 } 6419 6420 /* Calculate CPU power for physical packages and nodes */ 6421 for (i = nr_cpumask_bits-1; i >= 0; i--) { 6422 if (!cpumask_test_cpu(i, cpu_map)) 6423 continue; 6424 6425 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { 6426 claim_allocations(i, sd); 6427 init_sched_groups_power(i, sd); 6428 } 6429 } 6430 6431 /* Attach the domains */ 6432 rcu_read_lock(); 6433 for_each_cpu(i, cpu_map) { 6434 sd = *per_cpu_ptr(d.sd, i); 6435 cpu_attach_domain(sd, d.rd, i); 6436 } 6437 rcu_read_unlock(); 6438 6439 ret = 0; 6440error: 6441 __free_domain_allocs(&d, alloc_state, cpu_map); 6442 return ret; 6443} 6444 6445static cpumask_var_t *doms_cur; /* current sched domains */ 6446static int ndoms_cur; /* number of sched domains in 'doms_cur' */ 6447static struct sched_domain_attr *dattr_cur; 6448 /* attribues of custom domains in 'doms_cur' */ 6449 6450/* 6451 * Special case: If a kmalloc of a doms_cur partition (array of 6452 * cpumask) fails, then fallback to a single sched domain, 6453 * as determined by the single cpumask fallback_doms. 6454 */ 6455static cpumask_var_t fallback_doms; 6456 6457/* 6458 * arch_update_cpu_topology lets virtualized architectures update the 6459 * cpu core maps. It is supposed to return 1 if the topology changed 6460 * or 0 if it stayed the same. 6461 */ 6462int __attribute__((weak)) arch_update_cpu_topology(void) 6463{ 6464 return 0; 6465} 6466 6467cpumask_var_t *alloc_sched_domains(unsigned int ndoms) 6468{ 6469 int i; 6470 cpumask_var_t *doms; 6471 6472 doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL); 6473 if (!doms) 6474 return NULL; 6475 for (i = 0; i < ndoms; i++) { 6476 if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) { 6477 free_sched_domains(doms, i); 6478 return NULL; 6479 } 6480 } 6481 return doms; 6482} 6483 6484void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms) 6485{ 6486 unsigned int i; 6487 for (i = 0; i < ndoms; i++) 6488 free_cpumask_var(doms[i]); 6489 kfree(doms); 6490} 6491 6492/* 6493 * Set up scheduler domains and groups. Callers must hold the hotplug lock. 6494 * For now this just excludes isolated cpus, but could be used to 6495 * exclude other special cases in the future. 6496 */ 6497static int init_sched_domains(const struct cpumask *cpu_map) 6498{ 6499 int err; 6500 6501 arch_update_cpu_topology(); 6502 ndoms_cur = 1; 6503 doms_cur = alloc_sched_domains(ndoms_cur); 6504 if (!doms_cur) 6505 doms_cur = &fallback_doms; 6506 cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map); 6507 dattr_cur = NULL; 6508 err = build_sched_domains(doms_cur[0], NULL); 6509 register_sched_domain_sysctl(); 6510 6511 return err; 6512} 6513 6514/* 6515 * Detach sched domains from a group of cpus specified in cpu_map 6516 * These cpus will now be attached to the NULL domain 6517 */ 6518static void detach_destroy_domains(const struct cpumask *cpu_map) 6519{ 6520 int i; 6521 6522 rcu_read_lock(); 6523 for_each_cpu(i, cpu_map) 6524 cpu_attach_domain(NULL, &def_root_domain, i); 6525 rcu_read_unlock(); 6526} 6527 6528/* handle null as "default" */ 6529static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur, 6530 struct sched_domain_attr *new, int idx_new) 6531{ 6532 struct sched_domain_attr tmp; 6533 6534 /* fast path */ 6535 if (!new && !cur) 6536 return 1; 6537 6538 tmp = SD_ATTR_INIT; 6539 return !memcmp(cur ? (cur + idx_cur) : &tmp, 6540 new ? (new + idx_new) : &tmp, 6541 sizeof(struct sched_domain_attr)); 6542} 6543 6544/* 6545 * Partition sched domains as specified by the 'ndoms_new' 6546 * cpumasks in the array doms_new[] of cpumasks. This compares 6547 * doms_new[] to the current sched domain partitioning, doms_cur[]. 6548 * It destroys each deleted domain and builds each new domain. 6549 * 6550 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'. 6551 * The masks don't intersect (don't overlap.) We should setup one 6552 * sched domain for each mask. CPUs not in any of the cpumasks will 6553 * not be load balanced. If the same cpumask appears both in the 6554 * current 'doms_cur' domains and in the new 'doms_new', we can leave 6555 * it as it is. 6556 * 6557 * The passed in 'doms_new' should be allocated using 6558 * alloc_sched_domains. This routine takes ownership of it and will 6559 * free_sched_domains it when done with it. If the caller failed the 6560 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1, 6561 * and partition_sched_domains() will fallback to the single partition 6562 * 'fallback_doms', it also forces the domains to be rebuilt. 6563 * 6564 * If doms_new == NULL it will be replaced with cpu_online_mask. 6565 * ndoms_new == 0 is a special case for destroying existing domains, 6566 * and it will not create the default domain. 6567 * 6568 * Call with hotplug lock held 6569 */ 6570void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[], 6571 struct sched_domain_attr *dattr_new) 6572{ 6573 int i, j, n; 6574 int new_topology; 6575 6576 mutex_lock(&sched_domains_mutex); 6577 6578 /* always unregister in case we don't destroy any domains */ 6579 unregister_sched_domain_sysctl(); 6580 6581 /* Let architecture update cpu core mappings. */ 6582 new_topology = arch_update_cpu_topology(); 6583 6584 n = doms_new ? ndoms_new : 0; 6585 6586 /* Destroy deleted domains */ 6587 for (i = 0; i < ndoms_cur; i++) { 6588 for (j = 0; j < n && !new_topology; j++) { 6589 if (cpumask_equal(doms_cur[i], doms_new[j]) 6590 && dattrs_equal(dattr_cur, i, dattr_new, j)) 6591 goto match1; 6592 } 6593 /* no match - a current sched domain not in new doms_new[] */ 6594 detach_destroy_domains(doms_cur[i]); 6595match1: 6596 ; 6597 } 6598 6599 if (doms_new == NULL) { 6600 ndoms_cur = 0; 6601 doms_new = &fallback_doms; 6602 cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map); 6603 WARN_ON_ONCE(dattr_new); 6604 } 6605 6606 /* Build new domains */ 6607 for (i = 0; i < ndoms_new; i++) { 6608 for (j = 0; j < ndoms_cur && !new_topology; j++) { 6609 if (cpumask_equal(doms_new[i], doms_cur[j]) 6610 && dattrs_equal(dattr_new, i, dattr_cur, j)) 6611 goto match2; 6612 } 6613 /* no match - add a new doms_new */ 6614 build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL); 6615match2: 6616 ; 6617 } 6618 6619 /* Remember the new sched domains */ 6620 if (doms_cur != &fallback_doms) 6621 free_sched_domains(doms_cur, ndoms_cur); 6622 kfree(dattr_cur); /* kfree(NULL) is safe */ 6623 doms_cur = doms_new; 6624 dattr_cur = dattr_new; 6625 ndoms_cur = ndoms_new; 6626 6627 register_sched_domain_sysctl(); 6628 6629 mutex_unlock(&sched_domains_mutex); 6630} 6631 6632#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) 6633static void reinit_sched_domains(void) 6634{ 6635 get_online_cpus(); 6636 6637 /* Destroy domains first to force the rebuild */ 6638 partition_sched_domains(0, NULL, NULL); 6639 6640 rebuild_sched_domains(); 6641 put_online_cpus(); 6642} 6643 6644static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt) 6645{ 6646 unsigned int level = 0; 6647 6648 if (sscanf(buf, "%u", &level) != 1) 6649 return -EINVAL; 6650 6651 /* 6652 * level is always be positive so don't check for 6653 * level < POWERSAVINGS_BALANCE_NONE which is 0 6654 * What happens on 0 or 1 byte write, 6655 * need to check for count as well? 6656 */ 6657 6658 if (level >= MAX_POWERSAVINGS_BALANCE_LEVELS) 6659 return -EINVAL; 6660 6661 if (smt) 6662 sched_smt_power_savings = level; 6663 else 6664 sched_mc_power_savings = level; 6665 6666 reinit_sched_domains(); 6667 6668 return count; 6669} 6670 6671#ifdef CONFIG_SCHED_MC 6672static ssize_t sched_mc_power_savings_show(struct device *dev, 6673 struct device_attribute *attr, 6674 char *buf) 6675{ 6676 return sprintf(buf, "%u\n", sched_mc_power_savings); 6677} 6678static ssize_t sched_mc_power_savings_store(struct device *dev, 6679 struct device_attribute *attr, 6680 const char *buf, size_t count) 6681{ 6682 return sched_power_savings_store(buf, count, 0); 6683} 6684static DEVICE_ATTR(sched_mc_power_savings, 0644, 6685 sched_mc_power_savings_show, 6686 sched_mc_power_savings_store); 6687#endif 6688 6689#ifdef CONFIG_SCHED_SMT 6690static ssize_t sched_smt_power_savings_show(struct device *dev, 6691 struct device_attribute *attr, 6692 char *buf) 6693{ 6694 return sprintf(buf, "%u\n", sched_smt_power_savings); 6695} 6696static ssize_t sched_smt_power_savings_store(struct device *dev, 6697 struct device_attribute *attr, 6698 const char *buf, size_t count) 6699{ 6700 return sched_power_savings_store(buf, count, 1); 6701} 6702static DEVICE_ATTR(sched_smt_power_savings, 0644, 6703 sched_smt_power_savings_show, 6704 sched_smt_power_savings_store); 6705#endif 6706 6707int __init sched_create_sysfs_power_savings_entries(struct device *dev) 6708{ 6709 int err = 0; 6710 6711#ifdef CONFIG_SCHED_SMT 6712 if (smt_capable()) 6713 err = device_create_file(dev, &dev_attr_sched_smt_power_savings); 6714#endif 6715#ifdef CONFIG_SCHED_MC 6716 if (!err && mc_capable()) 6717 err = device_create_file(dev, &dev_attr_sched_mc_power_savings); 6718#endif 6719 return err; 6720} 6721#endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */ 6722 6723/* 6724 * Update cpusets according to cpu_active mask. If cpusets are 6725 * disabled, cpuset_update_active_cpus() becomes a simple wrapper 6726 * around partition_sched_domains(). 6727 */ 6728static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action, 6729 void *hcpu) 6730{ 6731 switch (action & ~CPU_TASKS_FROZEN) { 6732 case CPU_ONLINE: 6733 case CPU_DOWN_FAILED: 6734 cpuset_update_active_cpus(); 6735 return NOTIFY_OK; 6736 default: 6737 return NOTIFY_DONE; 6738 } 6739} 6740 6741static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action, 6742 void *hcpu) 6743{ 6744 switch (action & ~CPU_TASKS_FROZEN) { 6745 case CPU_DOWN_PREPARE: 6746 cpuset_update_active_cpus(); 6747 return NOTIFY_OK; 6748 default: 6749 return NOTIFY_DONE; 6750 } 6751} 6752 6753void __init sched_init_smp(void) 6754{ 6755 cpumask_var_t non_isolated_cpus; 6756 6757 alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL); 6758 alloc_cpumask_var(&fallback_doms, GFP_KERNEL); 6759 6760 get_online_cpus(); 6761 mutex_lock(&sched_domains_mutex); 6762 init_sched_domains(cpu_active_mask); 6763 cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map); 6764 if (cpumask_empty(non_isolated_cpus)) 6765 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus); 6766 mutex_unlock(&sched_domains_mutex); 6767 put_online_cpus(); 6768 6769 hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE); 6770 hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE); 6771 6772 /* RT runtime code needs to handle some hotplug events */ 6773 hotcpu_notifier(update_runtime, 0); 6774 6775 init_hrtick(); 6776 6777 /* Move init over to a non-isolated CPU */ 6778 if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0) 6779 BUG(); 6780 sched_init_granularity(); 6781 free_cpumask_var(non_isolated_cpus); 6782 6783 init_sched_rt_class(); 6784} 6785#else 6786void __init sched_init_smp(void) 6787{ 6788 sched_init_granularity(); 6789} 6790#endif /* CONFIG_SMP */ 6791 6792const_debug unsigned int sysctl_timer_migration = 1; 6793 6794int in_sched_functions(unsigned long addr) 6795{ 6796 return in_lock_functions(addr) || 6797 (addr >= (unsigned long)__sched_text_start 6798 && addr < (unsigned long)__sched_text_end); 6799} 6800 6801#ifdef CONFIG_CGROUP_SCHED 6802struct task_group root_task_group; 6803#endif 6804 6805DECLARE_PER_CPU(cpumask_var_t, load_balance_tmpmask); 6806 6807void __init sched_init(void) 6808{ 6809 int i, j; 6810 unsigned long alloc_size = 0, ptr; 6811 6812#ifdef CONFIG_FAIR_GROUP_SCHED 6813 alloc_size += 2 * nr_cpu_ids * sizeof(void **); 6814#endif 6815#ifdef CONFIG_RT_GROUP_SCHED 6816 alloc_size += 2 * nr_cpu_ids * sizeof(void **); 6817#endif 6818#ifdef CONFIG_CPUMASK_OFFSTACK 6819 alloc_size += num_possible_cpus() * cpumask_size(); 6820#endif 6821 if (alloc_size) { 6822 ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT); 6823 6824#ifdef CONFIG_FAIR_GROUP_SCHED 6825 root_task_group.se = (struct sched_entity **)ptr; 6826 ptr += nr_cpu_ids * sizeof(void **); 6827 6828 root_task_group.cfs_rq = (struct cfs_rq **)ptr; 6829 ptr += nr_cpu_ids * sizeof(void **); 6830 6831#endif /* CONFIG_FAIR_GROUP_SCHED */ 6832#ifdef CONFIG_RT_GROUP_SCHED 6833 root_task_group.rt_se = (struct sched_rt_entity **)ptr; 6834 ptr += nr_cpu_ids * sizeof(void **); 6835 6836 root_task_group.rt_rq = (struct rt_rq **)ptr; 6837 ptr += nr_cpu_ids * sizeof(void **); 6838 6839#endif /* CONFIG_RT_GROUP_SCHED */ 6840#ifdef CONFIG_CPUMASK_OFFSTACK 6841 for_each_possible_cpu(i) { 6842 per_cpu(load_balance_tmpmask, i) = (void *)ptr; 6843 ptr += cpumask_size(); 6844 } 6845#endif /* CONFIG_CPUMASK_OFFSTACK */ 6846 } 6847 6848#ifdef CONFIG_SMP 6849 init_defrootdomain(); 6850#endif 6851 6852 init_rt_bandwidth(&def_rt_bandwidth, 6853 global_rt_period(), global_rt_runtime()); 6854 6855#ifdef CONFIG_RT_GROUP_SCHED 6856 init_rt_bandwidth(&root_task_group.rt_bandwidth, 6857 global_rt_period(), global_rt_runtime()); 6858#endif /* CONFIG_RT_GROUP_SCHED */ 6859 6860#ifdef CONFIG_CGROUP_SCHED 6861 list_add(&root_task_group.list, &task_groups); 6862 INIT_LIST_HEAD(&root_task_group.children); 6863 INIT_LIST_HEAD(&root_task_group.siblings); 6864 autogroup_init(&init_task); 6865 6866#endif /* CONFIG_CGROUP_SCHED */ 6867 6868#ifdef CONFIG_CGROUP_CPUACCT 6869 root_cpuacct.cpustat = &kernel_cpustat; 6870 root_cpuacct.cpuusage = alloc_percpu(u64); 6871 /* Too early, not expected to fail */ 6872 BUG_ON(!root_cpuacct.cpuusage); 6873#endif 6874 for_each_possible_cpu(i) { 6875 struct rq *rq; 6876 6877 rq = cpu_rq(i); 6878 raw_spin_lock_init(&rq->lock); 6879 rq->nr_running = 0; 6880 rq->calc_load_active = 0; 6881 rq->calc_load_update = jiffies + LOAD_FREQ; 6882 init_cfs_rq(&rq->cfs); 6883 init_rt_rq(&rq->rt, rq); 6884#ifdef CONFIG_FAIR_GROUP_SCHED 6885 root_task_group.shares = ROOT_TASK_GROUP_LOAD; 6886 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list); 6887 /* 6888 * How much cpu bandwidth does root_task_group get? 6889 * 6890 * In case of task-groups formed thr' the cgroup filesystem, it 6891 * gets 100% of the cpu resources in the system. This overall 6892 * system cpu resource is divided among the tasks of 6893 * root_task_group and its child task-groups in a fair manner, 6894 * based on each entity's (task or task-group's) weight 6895 * (se->load.weight). 6896 * 6897 * In other words, if root_task_group has 10 tasks of weight 6898 * 1024) and two child groups A0 and A1 (of weight 1024 each), 6899 * then A0's share of the cpu resource is: 6900 * 6901 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33% 6902 * 6903 * We achieve this by letting root_task_group's tasks sit 6904 * directly in rq->cfs (i.e root_task_group->se[] = NULL). 6905 */ 6906 init_cfs_bandwidth(&root_task_group.cfs_bandwidth); 6907 init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL); 6908#endif /* CONFIG_FAIR_GROUP_SCHED */ 6909 6910 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime; 6911#ifdef CONFIG_RT_GROUP_SCHED 6912 INIT_LIST_HEAD(&rq->leaf_rt_rq_list); 6913 init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL); 6914#endif 6915 6916 for (j = 0; j < CPU_LOAD_IDX_MAX; j++) 6917 rq->cpu_load[j] = 0; 6918 6919 rq->last_load_update_tick = jiffies; 6920 6921#ifdef CONFIG_SMP 6922 rq->sd = NULL; 6923 rq->rd = NULL; 6924 rq->cpu_power = SCHED_POWER_SCALE; 6925 rq->post_schedule = 0; 6926 rq->active_balance = 0; 6927 rq->next_balance = jiffies; 6928 rq->push_cpu = 0; 6929 rq->cpu = i; 6930 rq->online = 0; 6931 rq->idle_stamp = 0; 6932 rq->avg_idle = 2*sysctl_sched_migration_cost; 6933 rq_attach_root(rq, &def_root_domain); 6934#ifdef CONFIG_NO_HZ 6935 rq->nohz_flags = 0; 6936#endif 6937#endif 6938 init_rq_hrtick(rq); 6939 atomic_set(&rq->nr_iowait, 0); 6940 } 6941 6942 set_load_weight(&init_task); 6943 6944#ifdef CONFIG_PREEMPT_NOTIFIERS 6945 INIT_HLIST_HEAD(&init_task.preempt_notifiers); 6946#endif 6947 6948#ifdef CONFIG_RT_MUTEXES 6949 plist_head_init(&init_task.pi_waiters); 6950#endif 6951 6952 /* 6953 * The boot idle thread does lazy MMU switching as well: 6954 */ 6955 atomic_inc(&init_mm.mm_count); 6956 enter_lazy_tlb(&init_mm, current); 6957 6958 /* 6959 * Make us the idle thread. Technically, schedule() should not be 6960 * called from this thread, however somewhere below it might be, 6961 * but because we are the idle thread, we just pick up running again 6962 * when this runqueue becomes "idle". 6963 */ 6964 init_idle(current, smp_processor_id()); 6965 6966 calc_load_update = jiffies + LOAD_FREQ; 6967 6968 /* 6969 * During early bootup we pretend to be a normal task: 6970 */ 6971 current->sched_class = &fair_sched_class; 6972 6973#ifdef CONFIG_SMP 6974 zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT); 6975 /* May be allocated at isolcpus cmdline parse time */ 6976 if (cpu_isolated_map == NULL) 6977 zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT); 6978#endif 6979 init_sched_fair_class(); 6980 6981 scheduler_running = 1; 6982} 6983 6984#ifdef CONFIG_DEBUG_ATOMIC_SLEEP 6985static inline int preempt_count_equals(int preempt_offset) 6986{ 6987 int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth(); 6988 6989 return (nested == preempt_offset); 6990} 6991 6992void __might_sleep(const char *file, int line, int preempt_offset) 6993{ 6994 static unsigned long prev_jiffy; /* ratelimiting */ 6995 6996 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */ 6997 if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) || 6998 system_state != SYSTEM_RUNNING || oops_in_progress) 6999 return; 7000 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) 7001 return; 7002 prev_jiffy = jiffies; 7003 7004 printk(KERN_ERR 7005 "BUG: sleeping function called from invalid context at %s:%d\n", 7006 file, line); 7007 printk(KERN_ERR 7008 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n", 7009 in_atomic(), irqs_disabled(), 7010 current->pid, current->comm); 7011 7012 debug_show_held_locks(current); 7013 if (irqs_disabled()) 7014 print_irqtrace_events(current); 7015 dump_stack(); 7016} 7017EXPORT_SYMBOL(__might_sleep); 7018#endif 7019 7020#ifdef CONFIG_MAGIC_SYSRQ 7021static void normalize_task(struct rq *rq, struct task_struct *p) 7022{ 7023 const struct sched_class *prev_class = p->sched_class; 7024 int old_prio = p->prio; 7025 int on_rq; 7026 7027 on_rq = p->on_rq; 7028 if (on_rq) 7029 dequeue_task(rq, p, 0); 7030 __setscheduler(rq, p, SCHED_NORMAL, 0); 7031 if (on_rq) { 7032 enqueue_task(rq, p, 0); 7033 resched_task(rq->curr); 7034 } 7035 7036 check_class_changed(rq, p, prev_class, old_prio); 7037} 7038 7039void normalize_rt_tasks(void) 7040{ 7041 struct task_struct *g, *p; 7042 unsigned long flags; 7043 struct rq *rq; 7044 7045 read_lock_irqsave(&tasklist_lock, flags); 7046 do_each_thread(g, p) { 7047 /* 7048 * Only normalize user tasks: 7049 */ 7050 if (!p->mm) 7051 continue; 7052 7053 p->se.exec_start = 0; 7054#ifdef CONFIG_SCHEDSTATS 7055 p->se.statistics.wait_start = 0; 7056 p->se.statistics.sleep_start = 0; 7057 p->se.statistics.block_start = 0; 7058#endif 7059 7060 if (!rt_task(p)) { 7061 /* 7062 * Renice negative nice level userspace 7063 * tasks back to 0: 7064 */ 7065 if (TASK_NICE(p) < 0 && p->mm) 7066 set_user_nice(p, 0); 7067 continue; 7068 } 7069 7070 raw_spin_lock(&p->pi_lock); 7071 rq = __task_rq_lock(p); 7072 7073 normalize_task(rq, p); 7074 7075 __task_rq_unlock(rq); 7076 raw_spin_unlock(&p->pi_lock); 7077 } while_each_thread(g, p); 7078 7079 read_unlock_irqrestore(&tasklist_lock, flags); 7080} 7081 7082#endif /* CONFIG_MAGIC_SYSRQ */ 7083 7084#if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) 7085/* 7086 * These functions are only useful for the IA64 MCA handling, or kdb. 7087 * 7088 * They can only be called when the whole system has been 7089 * stopped - every CPU needs to be quiescent, and no scheduling 7090 * activity can take place. Using them for anything else would 7091 * be a serious bug, and as a result, they aren't even visible 7092 * under any other configuration. 7093 */ 7094 7095/** 7096 * curr_task - return the current task for a given cpu. 7097 * @cpu: the processor in question. 7098 * 7099 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! 7100 */ 7101struct task_struct *curr_task(int cpu) 7102{ 7103 return cpu_curr(cpu); 7104} 7105 7106#endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */ 7107 7108#ifdef CONFIG_IA64 7109/** 7110 * set_curr_task - set the current task for a given cpu. 7111 * @cpu: the processor in question. 7112 * @p: the task pointer to set. 7113 * 7114 * Description: This function must only be used when non-maskable interrupts 7115 * are serviced on a separate stack. It allows the architecture to switch the 7116 * notion of the current task on a cpu in a non-blocking manner. This function 7117 * must be called with all CPU's synchronized, and interrupts disabled, the 7118 * and caller must save the original value of the current task (see 7119 * curr_task() above) and restore that value before reenabling interrupts and 7120 * re-starting the system. 7121 * 7122 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! 7123 */ 7124void set_curr_task(int cpu, struct task_struct *p) 7125{ 7126 cpu_curr(cpu) = p; 7127} 7128 7129#endif 7130 7131#ifdef CONFIG_CGROUP_SCHED 7132/* task_group_lock serializes the addition/removal of task groups */ 7133static DEFINE_SPINLOCK(task_group_lock); 7134 7135static void free_sched_group(struct task_group *tg) 7136{ 7137 free_fair_sched_group(tg); 7138 free_rt_sched_group(tg); 7139 autogroup_free(tg); 7140 kfree(tg); 7141} 7142 7143/* allocate runqueue etc for a new task group */ 7144struct task_group *sched_create_group(struct task_group *parent) 7145{ 7146 struct task_group *tg; 7147 unsigned long flags; 7148 7149 tg = kzalloc(sizeof(*tg), GFP_KERNEL); 7150 if (!tg) 7151 return ERR_PTR(-ENOMEM); 7152 7153 if (!alloc_fair_sched_group(tg, parent)) 7154 goto err; 7155 7156 if (!alloc_rt_sched_group(tg, parent)) 7157 goto err; 7158 7159 spin_lock_irqsave(&task_group_lock, flags); 7160 list_add_rcu(&tg->list, &task_groups); 7161 7162 WARN_ON(!parent); /* root should already exist */ 7163 7164 tg->parent = parent; 7165 INIT_LIST_HEAD(&tg->children); 7166 list_add_rcu(&tg->siblings, &parent->children); 7167 spin_unlock_irqrestore(&task_group_lock, flags); 7168 7169 return tg; 7170 7171err: 7172 free_sched_group(tg); 7173 return ERR_PTR(-ENOMEM); 7174} 7175 7176/* rcu callback to free various structures associated with a task group */ 7177static void free_sched_group_rcu(struct rcu_head *rhp) 7178{ 7179 /* now it should be safe to free those cfs_rqs */ 7180 free_sched_group(container_of(rhp, struct task_group, rcu)); 7181} 7182 7183/* Destroy runqueue etc associated with a task group */ 7184void sched_destroy_group(struct task_group *tg) 7185{ 7186 unsigned long flags; 7187 int i; 7188 7189 /* end participation in shares distribution */ 7190 for_each_possible_cpu(i) 7191 unregister_fair_sched_group(tg, i); 7192 7193 spin_lock_irqsave(&task_group_lock, flags); 7194 list_del_rcu(&tg->list); 7195 list_del_rcu(&tg->siblings); 7196 spin_unlock_irqrestore(&task_group_lock, flags); 7197 7198 /* wait for possible concurrent references to cfs_rqs complete */ 7199 call_rcu(&tg->rcu, free_sched_group_rcu); 7200} 7201 7202/* change task's runqueue when it moves between groups. 7203 * The caller of this function should have put the task in its new group 7204 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to 7205 * reflect its new group. 7206 */ 7207void sched_move_task(struct task_struct *tsk) 7208{ 7209 int on_rq, running; 7210 unsigned long flags; 7211 struct rq *rq; 7212 7213 rq = task_rq_lock(tsk, &flags); 7214 7215 running = task_current(rq, tsk); 7216 on_rq = tsk->on_rq; 7217 7218 if (on_rq) 7219 dequeue_task(rq, tsk, 0); 7220 if (unlikely(running)) 7221 tsk->sched_class->put_prev_task(rq, tsk); 7222 7223#ifdef CONFIG_FAIR_GROUP_SCHED 7224 if (tsk->sched_class->task_move_group) 7225 tsk->sched_class->task_move_group(tsk, on_rq); 7226 else 7227#endif 7228 set_task_rq(tsk, task_cpu(tsk)); 7229 7230 if (unlikely(running)) 7231 tsk->sched_class->set_curr_task(rq); 7232 if (on_rq) 7233 enqueue_task(rq, tsk, 0); 7234 7235 task_rq_unlock(rq, tsk, &flags); 7236} 7237#endif /* CONFIG_CGROUP_SCHED */ 7238 7239#if defined(CONFIG_RT_GROUP_SCHED) || defined(CONFIG_CFS_BANDWIDTH) 7240static unsigned long to_ratio(u64 period, u64 runtime) 7241{ 7242 if (runtime == RUNTIME_INF) 7243 return 1ULL << 20; 7244 7245 return div64_u64(runtime << 20, period); 7246} 7247#endif 7248 7249#ifdef CONFIG_RT_GROUP_SCHED 7250/* 7251 * Ensure that the real time constraints are schedulable. 7252 */ 7253static DEFINE_MUTEX(rt_constraints_mutex); 7254 7255/* Must be called with tasklist_lock held */ 7256static inline int tg_has_rt_tasks(struct task_group *tg) 7257{ 7258 struct task_struct *g, *p; 7259 7260 do_each_thread(g, p) { 7261 if (rt_task(p) && task_rq(p)->rt.tg == tg) 7262 return 1; 7263 } while_each_thread(g, p); 7264 7265 return 0; 7266} 7267 7268struct rt_schedulable_data { 7269 struct task_group *tg; 7270 u64 rt_period; 7271 u64 rt_runtime; 7272}; 7273 7274static int tg_rt_schedulable(struct task_group *tg, void *data) 7275{ 7276 struct rt_schedulable_data *d = data; 7277 struct task_group *child; 7278 unsigned long total, sum = 0; 7279 u64 period, runtime; 7280 7281 period = ktime_to_ns(tg->rt_bandwidth.rt_period); 7282 runtime = tg->rt_bandwidth.rt_runtime; 7283 7284 if (tg == d->tg) { 7285 period = d->rt_period; 7286 runtime = d->rt_runtime; 7287 } 7288 7289 /* 7290 * Cannot have more runtime than the period. 7291 */ 7292 if (runtime > period && runtime != RUNTIME_INF) 7293 return -EINVAL; 7294 7295 /* 7296 * Ensure we don't starve existing RT tasks. 7297 */ 7298 if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg)) 7299 return -EBUSY; 7300 7301 total = to_ratio(period, runtime); 7302 7303 /* 7304 * Nobody can have more than the global setting allows. 7305 */ 7306 if (total > to_ratio(global_rt_period(), global_rt_runtime())) 7307 return -EINVAL; 7308 7309 /* 7310 * The sum of our children's runtime should not exceed our own. 7311 */ 7312 list_for_each_entry_rcu(child, &tg->children, siblings) { 7313 period = ktime_to_ns(child->rt_bandwidth.rt_period); 7314 runtime = child->rt_bandwidth.rt_runtime; 7315 7316 if (child == d->tg) { 7317 period = d->rt_period; 7318 runtime = d->rt_runtime; 7319 } 7320 7321 sum += to_ratio(period, runtime); 7322 } 7323 7324 if (sum > total) 7325 return -EINVAL; 7326 7327 return 0; 7328} 7329 7330static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime) 7331{ 7332 int ret; 7333 7334 struct rt_schedulable_data data = { 7335 .tg = tg, 7336 .rt_period = period, 7337 .rt_runtime = runtime, 7338 }; 7339 7340 rcu_read_lock(); 7341 ret = walk_tg_tree(tg_rt_schedulable, tg_nop, &data); 7342 rcu_read_unlock(); 7343 7344 return ret; 7345} 7346 7347static int tg_set_rt_bandwidth(struct task_group *tg, 7348 u64 rt_period, u64 rt_runtime) 7349{ 7350 int i, err = 0; 7351 7352 mutex_lock(&rt_constraints_mutex); 7353 read_lock(&tasklist_lock); 7354 err = __rt_schedulable(tg, rt_period, rt_runtime); 7355 if (err) 7356 goto unlock; 7357 7358 raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock); 7359 tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period); 7360 tg->rt_bandwidth.rt_runtime = rt_runtime; 7361 7362 for_each_possible_cpu(i) { 7363 struct rt_rq *rt_rq = tg->rt_rq[i]; 7364 7365 raw_spin_lock(&rt_rq->rt_runtime_lock); 7366 rt_rq->rt_runtime = rt_runtime; 7367 raw_spin_unlock(&rt_rq->rt_runtime_lock); 7368 } 7369 raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock); 7370unlock: 7371 read_unlock(&tasklist_lock); 7372 mutex_unlock(&rt_constraints_mutex); 7373 7374 return err; 7375} 7376 7377int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us) 7378{ 7379 u64 rt_runtime, rt_period; 7380 7381 rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period); 7382 rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC; 7383 if (rt_runtime_us < 0) 7384 rt_runtime = RUNTIME_INF; 7385 7386 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); 7387} 7388 7389long sched_group_rt_runtime(struct task_group *tg) 7390{ 7391 u64 rt_runtime_us; 7392 7393 if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF) 7394 return -1; 7395 7396 rt_runtime_us = tg->rt_bandwidth.rt_runtime; 7397 do_div(rt_runtime_us, NSEC_PER_USEC); 7398 return rt_runtime_us; 7399} 7400 7401int sched_group_set_rt_period(struct task_group *tg, long rt_period_us) 7402{ 7403 u64 rt_runtime, rt_period; 7404 7405 rt_period = (u64)rt_period_us * NSEC_PER_USEC; 7406 rt_runtime = tg->rt_bandwidth.rt_runtime; 7407 7408 if (rt_period == 0) 7409 return -EINVAL; 7410 7411 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); 7412} 7413 7414long sched_group_rt_period(struct task_group *tg) 7415{ 7416 u64 rt_period_us; 7417 7418 rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period); 7419 do_div(rt_period_us, NSEC_PER_USEC); 7420 return rt_period_us; 7421} 7422 7423static int sched_rt_global_constraints(void) 7424{ 7425 u64 runtime, period; 7426 int ret = 0; 7427 7428 if (sysctl_sched_rt_period <= 0) 7429 return -EINVAL; 7430 7431 runtime = global_rt_runtime(); 7432 period = global_rt_period(); 7433 7434 /* 7435 * Sanity check on the sysctl variables. 7436 */ 7437 if (runtime > period && runtime != RUNTIME_INF) 7438 return -EINVAL; 7439 7440 mutex_lock(&rt_constraints_mutex); 7441 read_lock(&tasklist_lock); 7442 ret = __rt_schedulable(NULL, 0, 0); 7443 read_unlock(&tasklist_lock); 7444 mutex_unlock(&rt_constraints_mutex); 7445 7446 return ret; 7447} 7448 7449int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk) 7450{ 7451 /* Don't accept realtime tasks when there is no way for them to run */ 7452 if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0) 7453 return 0; 7454 7455 return 1; 7456} 7457 7458#else /* !CONFIG_RT_GROUP_SCHED */ 7459static int sched_rt_global_constraints(void) 7460{ 7461 unsigned long flags; 7462 int i; 7463 7464 if (sysctl_sched_rt_period <= 0) 7465 return -EINVAL; 7466 7467 /* 7468 * There's always some RT tasks in the root group 7469 * -- migration, kstopmachine etc.. 7470 */ 7471 if (sysctl_sched_rt_runtime == 0) 7472 return -EBUSY; 7473 7474 raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags); 7475 for_each_possible_cpu(i) { 7476 struct rt_rq *rt_rq = &cpu_rq(i)->rt; 7477 7478 raw_spin_lock(&rt_rq->rt_runtime_lock); 7479 rt_rq->rt_runtime = global_rt_runtime(); 7480 raw_spin_unlock(&rt_rq->rt_runtime_lock); 7481 } 7482 raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags); 7483 7484 return 0; 7485} 7486#endif /* CONFIG_RT_GROUP_SCHED */ 7487 7488int sched_rt_handler(struct ctl_table *table, int write, 7489 void __user *buffer, size_t *lenp, 7490 loff_t *ppos) 7491{ 7492 int ret; 7493 int old_period, old_runtime; 7494 static DEFINE_MUTEX(mutex); 7495 7496 mutex_lock(&mutex); 7497 old_period = sysctl_sched_rt_period; 7498 old_runtime = sysctl_sched_rt_runtime; 7499 7500 ret = proc_dointvec(table, write, buffer, lenp, ppos); 7501 7502 if (!ret && write) { 7503 ret = sched_rt_global_constraints(); 7504 if (ret) { 7505 sysctl_sched_rt_period = old_period; 7506 sysctl_sched_rt_runtime = old_runtime; 7507 } else { 7508 def_rt_bandwidth.rt_runtime = global_rt_runtime(); 7509 def_rt_bandwidth.rt_period = 7510 ns_to_ktime(global_rt_period()); 7511 } 7512 } 7513 mutex_unlock(&mutex); 7514 7515 return ret; 7516} 7517 7518#ifdef CONFIG_CGROUP_SCHED 7519 7520/* return corresponding task_group object of a cgroup */ 7521static inline struct task_group *cgroup_tg(struct cgroup *cgrp) 7522{ 7523 return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id), 7524 struct task_group, css); 7525} 7526 7527static struct cgroup_subsys_state * 7528cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp) 7529{ 7530 struct task_group *tg, *parent; 7531 7532 if (!cgrp->parent) { 7533 /* This is early initialization for the top cgroup */ 7534 return &root_task_group.css; 7535 } 7536 7537 parent = cgroup_tg(cgrp->parent); 7538 tg = sched_create_group(parent); 7539 if (IS_ERR(tg)) 7540 return ERR_PTR(-ENOMEM); 7541 7542 return &tg->css; 7543} 7544 7545static void 7546cpu_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp) 7547{ 7548 struct task_group *tg = cgroup_tg(cgrp); 7549 7550 sched_destroy_group(tg); 7551} 7552 7553static int cpu_cgroup_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp, 7554 struct cgroup_taskset *tset) 7555{ 7556 struct task_struct *task; 7557 7558 cgroup_taskset_for_each(task, cgrp, tset) { 7559#ifdef CONFIG_RT_GROUP_SCHED 7560 if (!sched_rt_can_attach(cgroup_tg(cgrp), task)) 7561 return -EINVAL; 7562#else 7563 /* We don't support RT-tasks being in separate groups */ 7564 if (task->sched_class != &fair_sched_class) 7565 return -EINVAL; 7566#endif 7567 } 7568 return 0; 7569} 7570 7571static void cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp, 7572 struct cgroup_taskset *tset) 7573{ 7574 struct task_struct *task; 7575 7576 cgroup_taskset_for_each(task, cgrp, tset) 7577 sched_move_task(task); 7578} 7579 7580static void 7581cpu_cgroup_exit(struct cgroup_subsys *ss, struct cgroup *cgrp, 7582 struct cgroup *old_cgrp, struct task_struct *task) 7583{ 7584 /* 7585 * cgroup_exit() is called in the copy_process() failure path. 7586 * Ignore this case since the task hasn't ran yet, this avoids 7587 * trying to poke a half freed task state from generic code. 7588 */ 7589 if (!(task->flags & PF_EXITING)) 7590 return; 7591 7592 sched_move_task(task); 7593} 7594 7595#ifdef CONFIG_FAIR_GROUP_SCHED 7596static int cpu_shares_write_u64(struct cgroup *cgrp, struct cftype *cftype, 7597 u64 shareval) 7598{ 7599 return sched_group_set_shares(cgroup_tg(cgrp), scale_load(shareval)); 7600} 7601 7602static u64 cpu_shares_read_u64(struct cgroup *cgrp, struct cftype *cft) 7603{ 7604 struct task_group *tg = cgroup_tg(cgrp); 7605 7606 return (u64) scale_load_down(tg->shares); 7607} 7608 7609#ifdef CONFIG_CFS_BANDWIDTH 7610static DEFINE_MUTEX(cfs_constraints_mutex); 7611 7612const u64 max_cfs_quota_period = 1 * NSEC_PER_SEC; /* 1s */ 7613const u64 min_cfs_quota_period = 1 * NSEC_PER_MSEC; /* 1ms */ 7614 7615static int __cfs_schedulable(struct task_group *tg, u64 period, u64 runtime); 7616 7617static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota) 7618{ 7619 int i, ret = 0, runtime_enabled, runtime_was_enabled; 7620 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 7621 7622 if (tg == &root_task_group) 7623 return -EINVAL; 7624 7625 /* 7626 * Ensure we have at some amount of bandwidth every period. This is 7627 * to prevent reaching a state of large arrears when throttled via 7628 * entity_tick() resulting in prolonged exit starvation. 7629 */ 7630 if (quota < min_cfs_quota_period || period < min_cfs_quota_period) 7631 return -EINVAL; 7632 7633 /* 7634 * Likewise, bound things on the otherside by preventing insane quota 7635 * periods. This also allows us to normalize in computing quota 7636 * feasibility. 7637 */ 7638 if (period > max_cfs_quota_period) 7639 return -EINVAL; 7640 7641 mutex_lock(&cfs_constraints_mutex); 7642 ret = __cfs_schedulable(tg, period, quota); 7643 if (ret) 7644 goto out_unlock; 7645 7646 runtime_enabled = quota != RUNTIME_INF; 7647 runtime_was_enabled = cfs_b->quota != RUNTIME_INF; 7648 account_cfs_bandwidth_used(runtime_enabled, runtime_was_enabled); 7649 raw_spin_lock_irq(&cfs_b->lock); 7650 cfs_b->period = ns_to_ktime(period); 7651 cfs_b->quota = quota; 7652 7653 __refill_cfs_bandwidth_runtime(cfs_b); 7654 /* restart the period timer (if active) to handle new period expiry */ 7655 if (runtime_enabled && cfs_b->timer_active) { 7656 /* force a reprogram */ 7657 cfs_b->timer_active = 0; 7658 __start_cfs_bandwidth(cfs_b); 7659 } 7660 raw_spin_unlock_irq(&cfs_b->lock); 7661 7662 for_each_possible_cpu(i) { 7663 struct cfs_rq *cfs_rq = tg->cfs_rq[i]; 7664 struct rq *rq = cfs_rq->rq; 7665 7666 raw_spin_lock_irq(&rq->lock); 7667 cfs_rq->runtime_enabled = runtime_enabled; 7668 cfs_rq->runtime_remaining = 0; 7669 7670 if (cfs_rq->throttled) 7671 unthrottle_cfs_rq(cfs_rq); 7672 raw_spin_unlock_irq(&rq->lock); 7673 } 7674out_unlock: 7675 mutex_unlock(&cfs_constraints_mutex); 7676 7677 return ret; 7678} 7679 7680int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us) 7681{ 7682 u64 quota, period; 7683 7684 period = ktime_to_ns(tg->cfs_bandwidth.period); 7685 if (cfs_quota_us < 0) 7686 quota = RUNTIME_INF; 7687 else 7688 quota = (u64)cfs_quota_us * NSEC_PER_USEC; 7689 7690 return tg_set_cfs_bandwidth(tg, period, quota); 7691} 7692 7693long tg_get_cfs_quota(struct task_group *tg) 7694{ 7695 u64 quota_us; 7696 7697 if (tg->cfs_bandwidth.quota == RUNTIME_INF) 7698 return -1; 7699 7700 quota_us = tg->cfs_bandwidth.quota; 7701 do_div(quota_us, NSEC_PER_USEC); 7702 7703 return quota_us; 7704} 7705 7706int tg_set_cfs_period(struct task_group *tg, long cfs_period_us) 7707{ 7708 u64 quota, period; 7709 7710 period = (u64)cfs_period_us * NSEC_PER_USEC; 7711 quota = tg->cfs_bandwidth.quota; 7712 7713 return tg_set_cfs_bandwidth(tg, period, quota); 7714} 7715 7716long tg_get_cfs_period(struct task_group *tg) 7717{ 7718 u64 cfs_period_us; 7719 7720 cfs_period_us = ktime_to_ns(tg->cfs_bandwidth.period); 7721 do_div(cfs_period_us, NSEC_PER_USEC); 7722 7723 return cfs_period_us; 7724} 7725 7726static s64 cpu_cfs_quota_read_s64(struct cgroup *cgrp, struct cftype *cft) 7727{ 7728 return tg_get_cfs_quota(cgroup_tg(cgrp)); 7729} 7730 7731static int cpu_cfs_quota_write_s64(struct cgroup *cgrp, struct cftype *cftype, 7732 s64 cfs_quota_us) 7733{ 7734 return tg_set_cfs_quota(cgroup_tg(cgrp), cfs_quota_us); 7735} 7736 7737static u64 cpu_cfs_period_read_u64(struct cgroup *cgrp, struct cftype *cft) 7738{ 7739 return tg_get_cfs_period(cgroup_tg(cgrp)); 7740} 7741 7742static int cpu_cfs_period_write_u64(struct cgroup *cgrp, struct cftype *cftype, 7743 u64 cfs_period_us) 7744{ 7745 return tg_set_cfs_period(cgroup_tg(cgrp), cfs_period_us); 7746} 7747 7748struct cfs_schedulable_data { 7749 struct task_group *tg; 7750 u64 period, quota; 7751}; 7752 7753/* 7754 * normalize group quota/period to be quota/max_period 7755 * note: units are usecs 7756 */ 7757static u64 normalize_cfs_quota(struct task_group *tg, 7758 struct cfs_schedulable_data *d) 7759{ 7760 u64 quota, period; 7761 7762 if (tg == d->tg) { 7763 period = d->period; 7764 quota = d->quota; 7765 } else { 7766 period = tg_get_cfs_period(tg); 7767 quota = tg_get_cfs_quota(tg); 7768 } 7769 7770 /* note: these should typically be equivalent */ 7771 if (quota == RUNTIME_INF || quota == -1) 7772 return RUNTIME_INF; 7773 7774 return to_ratio(period, quota); 7775} 7776 7777static int tg_cfs_schedulable_down(struct task_group *tg, void *data) 7778{ 7779 struct cfs_schedulable_data *d = data; 7780 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 7781 s64 quota = 0, parent_quota = -1; 7782 7783 if (!tg->parent) { 7784 quota = RUNTIME_INF; 7785 } else { 7786 struct cfs_bandwidth *parent_b = &tg->parent->cfs_bandwidth; 7787 7788 quota = normalize_cfs_quota(tg, d); 7789 parent_quota = parent_b->hierarchal_quota; 7790 7791 /* 7792 * ensure max(child_quota) <= parent_quota, inherit when no 7793 * limit is set 7794 */ 7795 if (quota == RUNTIME_INF) 7796 quota = parent_quota; 7797 else if (parent_quota != RUNTIME_INF && quota > parent_quota) 7798 return -EINVAL; 7799 } 7800 cfs_b->hierarchal_quota = quota; 7801 7802 return 0; 7803} 7804 7805static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota) 7806{ 7807 int ret; 7808 struct cfs_schedulable_data data = { 7809 .tg = tg, 7810 .period = period, 7811 .quota = quota, 7812 }; 7813 7814 if (quota != RUNTIME_INF) { 7815 do_div(data.period, NSEC_PER_USEC); 7816 do_div(data.quota, NSEC_PER_USEC); 7817 } 7818 7819 rcu_read_lock(); 7820 ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data); 7821 rcu_read_unlock(); 7822 7823 return ret; 7824} 7825 7826static int cpu_stats_show(struct cgroup *cgrp, struct cftype *cft, 7827 struct cgroup_map_cb *cb) 7828{ 7829 struct task_group *tg = cgroup_tg(cgrp); 7830 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 7831 7832 cb->fill(cb, "nr_periods", cfs_b->nr_periods); 7833 cb->fill(cb, "nr_throttled", cfs_b->nr_throttled); 7834 cb->fill(cb, "throttled_time", cfs_b->throttled_time); 7835 7836 return 0; 7837} 7838#endif /* CONFIG_CFS_BANDWIDTH */ 7839#endif /* CONFIG_FAIR_GROUP_SCHED */ 7840 7841#ifdef CONFIG_RT_GROUP_SCHED 7842static int cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft, 7843 s64 val) 7844{ 7845 return sched_group_set_rt_runtime(cgroup_tg(cgrp), val); 7846} 7847 7848static s64 cpu_rt_runtime_read(struct cgroup *cgrp, struct cftype *cft) 7849{ 7850 return sched_group_rt_runtime(cgroup_tg(cgrp)); 7851} 7852 7853static int cpu_rt_period_write_uint(struct cgroup *cgrp, struct cftype *cftype, 7854 u64 rt_period_us) 7855{ 7856 return sched_group_set_rt_period(cgroup_tg(cgrp), rt_period_us); 7857} 7858 7859static u64 cpu_rt_period_read_uint(struct cgroup *cgrp, struct cftype *cft) 7860{ 7861 return sched_group_rt_period(cgroup_tg(cgrp)); 7862} 7863#endif /* CONFIG_RT_GROUP_SCHED */ 7864 7865static struct cftype cpu_files[] = { 7866#ifdef CONFIG_FAIR_GROUP_SCHED 7867 { 7868 .name = "shares", 7869 .read_u64 = cpu_shares_read_u64, 7870 .write_u64 = cpu_shares_write_u64, 7871 }, 7872#endif 7873#ifdef CONFIG_CFS_BANDWIDTH 7874 { 7875 .name = "cfs_quota_us", 7876 .read_s64 = cpu_cfs_quota_read_s64, 7877 .write_s64 = cpu_cfs_quota_write_s64, 7878 }, 7879 { 7880 .name = "cfs_period_us", 7881 .read_u64 = cpu_cfs_period_read_u64, 7882 .write_u64 = cpu_cfs_period_write_u64, 7883 }, 7884 { 7885 .name = "stat", 7886 .read_map = cpu_stats_show, 7887 }, 7888#endif 7889#ifdef CONFIG_RT_GROUP_SCHED 7890 { 7891 .name = "rt_runtime_us", 7892 .read_s64 = cpu_rt_runtime_read, 7893 .write_s64 = cpu_rt_runtime_write, 7894 }, 7895 { 7896 .name = "rt_period_us", 7897 .read_u64 = cpu_rt_period_read_uint, 7898 .write_u64 = cpu_rt_period_write_uint, 7899 }, 7900#endif 7901}; 7902 7903static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont) 7904{ 7905 return cgroup_add_files(cont, ss, cpu_files, ARRAY_SIZE(cpu_files)); 7906} 7907 7908struct cgroup_subsys cpu_cgroup_subsys = { 7909 .name = "cpu", 7910 .create = cpu_cgroup_create, 7911 .destroy = cpu_cgroup_destroy, 7912 .can_attach = cpu_cgroup_can_attach, 7913 .attach = cpu_cgroup_attach, 7914 .exit = cpu_cgroup_exit, 7915 .populate = cpu_cgroup_populate, 7916 .subsys_id = cpu_cgroup_subsys_id, 7917 .early_init = 1, 7918}; 7919 7920#endif /* CONFIG_CGROUP_SCHED */ 7921 7922#ifdef CONFIG_CGROUP_CPUACCT 7923 7924/* 7925 * CPU accounting code for task groups. 7926 * 7927 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh 7928 * (balbir@in.ibm.com). 7929 */ 7930 7931/* create a new cpu accounting group */ 7932static struct cgroup_subsys_state *cpuacct_create( 7933 struct cgroup_subsys *ss, struct cgroup *cgrp) 7934{ 7935 struct cpuacct *ca; 7936 7937 if (!cgrp->parent) 7938 return &root_cpuacct.css; 7939 7940 ca = kzalloc(sizeof(*ca), GFP_KERNEL); 7941 if (!ca) 7942 goto out; 7943 7944 ca->cpuusage = alloc_percpu(u64); 7945 if (!ca->cpuusage) 7946 goto out_free_ca; 7947 7948 ca->cpustat = alloc_percpu(struct kernel_cpustat); 7949 if (!ca->cpustat) 7950 goto out_free_cpuusage; 7951 7952 return &ca->css; 7953 7954out_free_cpuusage: 7955 free_percpu(ca->cpuusage); 7956out_free_ca: 7957 kfree(ca); 7958out: 7959 return ERR_PTR(-ENOMEM); 7960} 7961 7962/* destroy an existing cpu accounting group */ 7963static void 7964cpuacct_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp) 7965{ 7966 struct cpuacct *ca = cgroup_ca(cgrp); 7967 7968 free_percpu(ca->cpustat); 7969 free_percpu(ca->cpuusage); 7970 kfree(ca); 7971} 7972 7973static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu) 7974{ 7975 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); 7976 u64 data; 7977 7978#ifndef CONFIG_64BIT 7979 /* 7980 * Take rq->lock to make 64-bit read safe on 32-bit platforms. 7981 */ 7982 raw_spin_lock_irq(&cpu_rq(cpu)->lock); 7983 data = *cpuusage; 7984 raw_spin_unlock_irq(&cpu_rq(cpu)->lock); 7985#else 7986 data = *cpuusage; 7987#endif 7988 7989 return data; 7990} 7991 7992static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val) 7993{ 7994 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); 7995 7996#ifndef CONFIG_64BIT 7997 /* 7998 * Take rq->lock to make 64-bit write safe on 32-bit platforms. 7999 */ 8000 raw_spin_lock_irq(&cpu_rq(cpu)->lock); 8001 *cpuusage = val; 8002 raw_spin_unlock_irq(&cpu_rq(cpu)->lock); 8003#else 8004 *cpuusage = val; 8005#endif 8006} 8007 8008/* return total cpu usage (in nanoseconds) of a group */ 8009static u64 cpuusage_read(struct cgroup *cgrp, struct cftype *cft) 8010{ 8011 struct cpuacct *ca = cgroup_ca(cgrp); 8012 u64 totalcpuusage = 0; 8013 int i; 8014 8015 for_each_present_cpu(i) 8016 totalcpuusage += cpuacct_cpuusage_read(ca, i); 8017 8018 return totalcpuusage; 8019} 8020 8021static int cpuusage_write(struct cgroup *cgrp, struct cftype *cftype, 8022 u64 reset) 8023{ 8024 struct cpuacct *ca = cgroup_ca(cgrp); 8025 int err = 0; 8026 int i; 8027 8028 if (reset) { 8029 err = -EINVAL; 8030 goto out; 8031 } 8032 8033 for_each_present_cpu(i) 8034 cpuacct_cpuusage_write(ca, i, 0); 8035 8036out: 8037 return err; 8038} 8039 8040static int cpuacct_percpu_seq_read(struct cgroup *cgroup, struct cftype *cft, 8041 struct seq_file *m) 8042{ 8043 struct cpuacct *ca = cgroup_ca(cgroup); 8044 u64 percpu; 8045 int i; 8046 8047 for_each_present_cpu(i) { 8048 percpu = cpuacct_cpuusage_read(ca, i); 8049 seq_printf(m, "%llu ", (unsigned long long) percpu); 8050 } 8051 seq_printf(m, "\n"); 8052 return 0; 8053} 8054 8055static const char *cpuacct_stat_desc[] = { 8056 [CPUACCT_STAT_USER] = "user", 8057 [CPUACCT_STAT_SYSTEM] = "system", 8058}; 8059 8060static int cpuacct_stats_show(struct cgroup *cgrp, struct cftype *cft, 8061 struct cgroup_map_cb *cb) 8062{ 8063 struct cpuacct *ca = cgroup_ca(cgrp); 8064 int cpu; 8065 s64 val = 0; 8066 8067 for_each_online_cpu(cpu) { 8068 struct kernel_cpustat *kcpustat = per_cpu_ptr(ca->cpustat, cpu); 8069 val += kcpustat->cpustat[CPUTIME_USER]; 8070 val += kcpustat->cpustat[CPUTIME_NICE]; 8071 } 8072 val = cputime64_to_clock_t(val); 8073 cb->fill(cb, cpuacct_stat_desc[CPUACCT_STAT_USER], val); 8074 8075 val = 0; 8076 for_each_online_cpu(cpu) { 8077 struct kernel_cpustat *kcpustat = per_cpu_ptr(ca->cpustat, cpu); 8078 val += kcpustat->cpustat[CPUTIME_SYSTEM]; 8079 val += kcpustat->cpustat[CPUTIME_IRQ]; 8080 val += kcpustat->cpustat[CPUTIME_SOFTIRQ]; 8081 } 8082 8083 val = cputime64_to_clock_t(val); 8084 cb->fill(cb, cpuacct_stat_desc[CPUACCT_STAT_SYSTEM], val); 8085 8086 return 0; 8087} 8088 8089static struct cftype files[] = { 8090 { 8091 .name = "usage", 8092 .read_u64 = cpuusage_read, 8093 .write_u64 = cpuusage_write, 8094 }, 8095 { 8096 .name = "usage_percpu", 8097 .read_seq_string = cpuacct_percpu_seq_read, 8098 }, 8099 { 8100 .name = "stat", 8101 .read_map = cpuacct_stats_show, 8102 }, 8103}; 8104 8105static int cpuacct_populate(struct cgroup_subsys *ss, struct cgroup *cgrp) 8106{ 8107 return cgroup_add_files(cgrp, ss, files, ARRAY_SIZE(files)); 8108} 8109 8110/* 8111 * charge this task's execution time to its accounting group. 8112 * 8113 * called with rq->lock held. 8114 */ 8115void cpuacct_charge(struct task_struct *tsk, u64 cputime) 8116{ 8117 struct cpuacct *ca; 8118 int cpu; 8119 8120 if (unlikely(!cpuacct_subsys.active)) 8121 return; 8122 8123 cpu = task_cpu(tsk); 8124 8125 rcu_read_lock(); 8126 8127 ca = task_ca(tsk); 8128 8129 for (; ca; ca = parent_ca(ca)) { 8130 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); 8131 *cpuusage += cputime; 8132 } 8133 8134 rcu_read_unlock(); 8135} 8136 8137struct cgroup_subsys cpuacct_subsys = { 8138 .name = "cpuacct", 8139 .create = cpuacct_create, 8140 .destroy = cpuacct_destroy, 8141 .populate = cpuacct_populate, 8142 .subsys_id = cpuacct_subsys_id, 8143}; 8144#endif /* CONFIG_CGROUP_CPUACCT */ 8145