core.c revision 895dd92c032e1604aa0d7afaef7716e058343b67
1/* 2 * kernel/sched/core.c 3 * 4 * Kernel scheduler and related syscalls 5 * 6 * Copyright (C) 1991-2002 Linus Torvalds 7 * 8 * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and 9 * make semaphores SMP safe 10 * 1998-11-19 Implemented schedule_timeout() and related stuff 11 * by Andrea Arcangeli 12 * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar: 13 * hybrid priority-list and round-robin design with 14 * an array-switch method of distributing timeslices 15 * and per-CPU runqueues. Cleanups and useful suggestions 16 * by Davide Libenzi, preemptible kernel bits by Robert Love. 17 * 2003-09-03 Interactivity tuning by Con Kolivas. 18 * 2004-04-02 Scheduler domains code by Nick Piggin 19 * 2007-04-15 Work begun on replacing all interactivity tuning with a 20 * fair scheduling design by Con Kolivas. 21 * 2007-05-05 Load balancing (smp-nice) and other improvements 22 * by Peter Williams 23 * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith 24 * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri 25 * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins, 26 * Thomas Gleixner, Mike Kravetz 27 */ 28 29#include <linux/mm.h> 30#include <linux/module.h> 31#include <linux/nmi.h> 32#include <linux/init.h> 33#include <linux/uaccess.h> 34#include <linux/highmem.h> 35#include <asm/mmu_context.h> 36#include <linux/interrupt.h> 37#include <linux/capability.h> 38#include <linux/completion.h> 39#include <linux/kernel_stat.h> 40#include <linux/debug_locks.h> 41#include <linux/perf_event.h> 42#include <linux/security.h> 43#include <linux/notifier.h> 44#include <linux/profile.h> 45#include <linux/freezer.h> 46#include <linux/vmalloc.h> 47#include <linux/blkdev.h> 48#include <linux/delay.h> 49#include <linux/pid_namespace.h> 50#include <linux/smp.h> 51#include <linux/threads.h> 52#include <linux/timer.h> 53#include <linux/rcupdate.h> 54#include <linux/cpu.h> 55#include <linux/cpuset.h> 56#include <linux/percpu.h> 57#include <linux/proc_fs.h> 58#include <linux/seq_file.h> 59#include <linux/sysctl.h> 60#include <linux/syscalls.h> 61#include <linux/times.h> 62#include <linux/tsacct_kern.h> 63#include <linux/kprobes.h> 64#include <linux/delayacct.h> 65#include <linux/unistd.h> 66#include <linux/pagemap.h> 67#include <linux/hrtimer.h> 68#include <linux/tick.h> 69#include <linux/debugfs.h> 70#include <linux/ctype.h> 71#include <linux/ftrace.h> 72#include <linux/slab.h> 73#include <linux/init_task.h> 74#include <linux/binfmts.h> 75 76#include <asm/switch_to.h> 77#include <asm/tlb.h> 78#include <asm/irq_regs.h> 79#include <asm/mutex.h> 80#ifdef CONFIG_PARAVIRT 81#include <asm/paravirt.h> 82#endif 83 84#include "sched.h" 85#include "../workqueue_sched.h" 86#include "../smpboot.h" 87 88#define CREATE_TRACE_POINTS 89#include <trace/events/sched.h> 90 91void start_bandwidth_timer(struct hrtimer *period_timer, ktime_t period) 92{ 93 unsigned long delta; 94 ktime_t soft, hard, now; 95 96 for (;;) { 97 if (hrtimer_active(period_timer)) 98 break; 99 100 now = hrtimer_cb_get_time(period_timer); 101 hrtimer_forward(period_timer, now, period); 102 103 soft = hrtimer_get_softexpires(period_timer); 104 hard = hrtimer_get_expires(period_timer); 105 delta = ktime_to_ns(ktime_sub(hard, soft)); 106 __hrtimer_start_range_ns(period_timer, soft, delta, 107 HRTIMER_MODE_ABS_PINNED, 0); 108 } 109} 110 111DEFINE_MUTEX(sched_domains_mutex); 112DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); 113 114static void update_rq_clock_task(struct rq *rq, s64 delta); 115 116void update_rq_clock(struct rq *rq) 117{ 118 s64 delta; 119 120 if (rq->skip_clock_update > 0) 121 return; 122 123 delta = sched_clock_cpu(cpu_of(rq)) - rq->clock; 124 rq->clock += delta; 125 update_rq_clock_task(rq, delta); 126} 127 128/* 129 * Debugging: various feature bits 130 */ 131 132#define SCHED_FEAT(name, enabled) \ 133 (1UL << __SCHED_FEAT_##name) * enabled | 134 135const_debug unsigned int sysctl_sched_features = 136#include "features.h" 137 0; 138 139#undef SCHED_FEAT 140 141#ifdef CONFIG_SCHED_DEBUG 142#define SCHED_FEAT(name, enabled) \ 143 #name , 144 145static const char * const sched_feat_names[] = { 146#include "features.h" 147}; 148 149#undef SCHED_FEAT 150 151static int sched_feat_show(struct seq_file *m, void *v) 152{ 153 int i; 154 155 for (i = 0; i < __SCHED_FEAT_NR; i++) { 156 if (!(sysctl_sched_features & (1UL << i))) 157 seq_puts(m, "NO_"); 158 seq_printf(m, "%s ", sched_feat_names[i]); 159 } 160 seq_puts(m, "\n"); 161 162 return 0; 163} 164 165#ifdef HAVE_JUMP_LABEL 166 167#define jump_label_key__true STATIC_KEY_INIT_TRUE 168#define jump_label_key__false STATIC_KEY_INIT_FALSE 169 170#define SCHED_FEAT(name, enabled) \ 171 jump_label_key__##enabled , 172 173struct static_key sched_feat_keys[__SCHED_FEAT_NR] = { 174#include "features.h" 175}; 176 177#undef SCHED_FEAT 178 179static void sched_feat_disable(int i) 180{ 181 if (static_key_enabled(&sched_feat_keys[i])) 182 static_key_slow_dec(&sched_feat_keys[i]); 183} 184 185static void sched_feat_enable(int i) 186{ 187 if (!static_key_enabled(&sched_feat_keys[i])) 188 static_key_slow_inc(&sched_feat_keys[i]); 189} 190#else 191static void sched_feat_disable(int i) { }; 192static void sched_feat_enable(int i) { }; 193#endif /* HAVE_JUMP_LABEL */ 194 195static ssize_t 196sched_feat_write(struct file *filp, const char __user *ubuf, 197 size_t cnt, loff_t *ppos) 198{ 199 char buf[64]; 200 char *cmp; 201 int neg = 0; 202 int i; 203 204 if (cnt > 63) 205 cnt = 63; 206 207 if (copy_from_user(&buf, ubuf, cnt)) 208 return -EFAULT; 209 210 buf[cnt] = 0; 211 cmp = strstrip(buf); 212 213 if (strncmp(cmp, "NO_", 3) == 0) { 214 neg = 1; 215 cmp += 3; 216 } 217 218 for (i = 0; i < __SCHED_FEAT_NR; i++) { 219 if (strcmp(cmp, sched_feat_names[i]) == 0) { 220 if (neg) { 221 sysctl_sched_features &= ~(1UL << i); 222 sched_feat_disable(i); 223 } else { 224 sysctl_sched_features |= (1UL << i); 225 sched_feat_enable(i); 226 } 227 break; 228 } 229 } 230 231 if (i == __SCHED_FEAT_NR) 232 return -EINVAL; 233 234 *ppos += cnt; 235 236 return cnt; 237} 238 239static int sched_feat_open(struct inode *inode, struct file *filp) 240{ 241 return single_open(filp, sched_feat_show, NULL); 242} 243 244static const struct file_operations sched_feat_fops = { 245 .open = sched_feat_open, 246 .write = sched_feat_write, 247 .read = seq_read, 248 .llseek = seq_lseek, 249 .release = single_release, 250}; 251 252static __init int sched_init_debug(void) 253{ 254 debugfs_create_file("sched_features", 0644, NULL, NULL, 255 &sched_feat_fops); 256 257 return 0; 258} 259late_initcall(sched_init_debug); 260#endif /* CONFIG_SCHED_DEBUG */ 261 262/* 263 * Number of tasks to iterate in a single balance run. 264 * Limited because this is done with IRQs disabled. 265 */ 266const_debug unsigned int sysctl_sched_nr_migrate = 32; 267 268/* 269 * period over which we average the RT time consumption, measured 270 * in ms. 271 * 272 * default: 1s 273 */ 274const_debug unsigned int sysctl_sched_time_avg = MSEC_PER_SEC; 275 276/* 277 * period over which we measure -rt task cpu usage in us. 278 * default: 1s 279 */ 280unsigned int sysctl_sched_rt_period = 1000000; 281 282__read_mostly int scheduler_running; 283 284/* 285 * part of the period that we allow rt tasks to run in us. 286 * default: 0.95s 287 */ 288int sysctl_sched_rt_runtime = 950000; 289 290 291 292/* 293 * __task_rq_lock - lock the rq @p resides on. 294 */ 295static inline struct rq *__task_rq_lock(struct task_struct *p) 296 __acquires(rq->lock) 297{ 298 struct rq *rq; 299 300 lockdep_assert_held(&p->pi_lock); 301 302 for (;;) { 303 rq = task_rq(p); 304 raw_spin_lock(&rq->lock); 305 if (likely(rq == task_rq(p))) 306 return rq; 307 raw_spin_unlock(&rq->lock); 308 } 309} 310 311/* 312 * task_rq_lock - lock p->pi_lock and lock the rq @p resides on. 313 */ 314static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags) 315 __acquires(p->pi_lock) 316 __acquires(rq->lock) 317{ 318 struct rq *rq; 319 320 for (;;) { 321 raw_spin_lock_irqsave(&p->pi_lock, *flags); 322 rq = task_rq(p); 323 raw_spin_lock(&rq->lock); 324 if (likely(rq == task_rq(p))) 325 return rq; 326 raw_spin_unlock(&rq->lock); 327 raw_spin_unlock_irqrestore(&p->pi_lock, *flags); 328 } 329} 330 331static void __task_rq_unlock(struct rq *rq) 332 __releases(rq->lock) 333{ 334 raw_spin_unlock(&rq->lock); 335} 336 337static inline void 338task_rq_unlock(struct rq *rq, struct task_struct *p, unsigned long *flags) 339 __releases(rq->lock) 340 __releases(p->pi_lock) 341{ 342 raw_spin_unlock(&rq->lock); 343 raw_spin_unlock_irqrestore(&p->pi_lock, *flags); 344} 345 346/* 347 * this_rq_lock - lock this runqueue and disable interrupts. 348 */ 349static struct rq *this_rq_lock(void) 350 __acquires(rq->lock) 351{ 352 struct rq *rq; 353 354 local_irq_disable(); 355 rq = this_rq(); 356 raw_spin_lock(&rq->lock); 357 358 return rq; 359} 360 361#ifdef CONFIG_SCHED_HRTICK 362/* 363 * Use HR-timers to deliver accurate preemption points. 364 * 365 * Its all a bit involved since we cannot program an hrt while holding the 366 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a 367 * reschedule event. 368 * 369 * When we get rescheduled we reprogram the hrtick_timer outside of the 370 * rq->lock. 371 */ 372 373static void hrtick_clear(struct rq *rq) 374{ 375 if (hrtimer_active(&rq->hrtick_timer)) 376 hrtimer_cancel(&rq->hrtick_timer); 377} 378 379/* 380 * High-resolution timer tick. 381 * Runs from hardirq context with interrupts disabled. 382 */ 383static enum hrtimer_restart hrtick(struct hrtimer *timer) 384{ 385 struct rq *rq = container_of(timer, struct rq, hrtick_timer); 386 387 WARN_ON_ONCE(cpu_of(rq) != smp_processor_id()); 388 389 raw_spin_lock(&rq->lock); 390 update_rq_clock(rq); 391 rq->curr->sched_class->task_tick(rq, rq->curr, 1); 392 raw_spin_unlock(&rq->lock); 393 394 return HRTIMER_NORESTART; 395} 396 397#ifdef CONFIG_SMP 398/* 399 * called from hardirq (IPI) context 400 */ 401static void __hrtick_start(void *arg) 402{ 403 struct rq *rq = arg; 404 405 raw_spin_lock(&rq->lock); 406 hrtimer_restart(&rq->hrtick_timer); 407 rq->hrtick_csd_pending = 0; 408 raw_spin_unlock(&rq->lock); 409} 410 411/* 412 * Called to set the hrtick timer state. 413 * 414 * called with rq->lock held and irqs disabled 415 */ 416void hrtick_start(struct rq *rq, u64 delay) 417{ 418 struct hrtimer *timer = &rq->hrtick_timer; 419 ktime_t time = ktime_add_ns(timer->base->get_time(), delay); 420 421 hrtimer_set_expires(timer, time); 422 423 if (rq == this_rq()) { 424 hrtimer_restart(timer); 425 } else if (!rq->hrtick_csd_pending) { 426 __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd, 0); 427 rq->hrtick_csd_pending = 1; 428 } 429} 430 431static int 432hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu) 433{ 434 int cpu = (int)(long)hcpu; 435 436 switch (action) { 437 case CPU_UP_CANCELED: 438 case CPU_UP_CANCELED_FROZEN: 439 case CPU_DOWN_PREPARE: 440 case CPU_DOWN_PREPARE_FROZEN: 441 case CPU_DEAD: 442 case CPU_DEAD_FROZEN: 443 hrtick_clear(cpu_rq(cpu)); 444 return NOTIFY_OK; 445 } 446 447 return NOTIFY_DONE; 448} 449 450static __init void init_hrtick(void) 451{ 452 hotcpu_notifier(hotplug_hrtick, 0); 453} 454#else 455/* 456 * Called to set the hrtick timer state. 457 * 458 * called with rq->lock held and irqs disabled 459 */ 460void hrtick_start(struct rq *rq, u64 delay) 461{ 462 __hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0, 463 HRTIMER_MODE_REL_PINNED, 0); 464} 465 466static inline void init_hrtick(void) 467{ 468} 469#endif /* CONFIG_SMP */ 470 471static void init_rq_hrtick(struct rq *rq) 472{ 473#ifdef CONFIG_SMP 474 rq->hrtick_csd_pending = 0; 475 476 rq->hrtick_csd.flags = 0; 477 rq->hrtick_csd.func = __hrtick_start; 478 rq->hrtick_csd.info = rq; 479#endif 480 481 hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 482 rq->hrtick_timer.function = hrtick; 483} 484#else /* CONFIG_SCHED_HRTICK */ 485static inline void hrtick_clear(struct rq *rq) 486{ 487} 488 489static inline void init_rq_hrtick(struct rq *rq) 490{ 491} 492 493static inline void init_hrtick(void) 494{ 495} 496#endif /* CONFIG_SCHED_HRTICK */ 497 498/* 499 * resched_task - mark a task 'to be rescheduled now'. 500 * 501 * On UP this means the setting of the need_resched flag, on SMP it 502 * might also involve a cross-CPU call to trigger the scheduler on 503 * the target CPU. 504 */ 505#ifdef CONFIG_SMP 506 507#ifndef tsk_is_polling 508#define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG) 509#endif 510 511void resched_task(struct task_struct *p) 512{ 513 int cpu; 514 515 assert_raw_spin_locked(&task_rq(p)->lock); 516 517 if (test_tsk_need_resched(p)) 518 return; 519 520 set_tsk_need_resched(p); 521 522 cpu = task_cpu(p); 523 if (cpu == smp_processor_id()) 524 return; 525 526 /* NEED_RESCHED must be visible before we test polling */ 527 smp_mb(); 528 if (!tsk_is_polling(p)) 529 smp_send_reschedule(cpu); 530} 531 532void resched_cpu(int cpu) 533{ 534 struct rq *rq = cpu_rq(cpu); 535 unsigned long flags; 536 537 if (!raw_spin_trylock_irqsave(&rq->lock, flags)) 538 return; 539 resched_task(cpu_curr(cpu)); 540 raw_spin_unlock_irqrestore(&rq->lock, flags); 541} 542 543#ifdef CONFIG_NO_HZ 544/* 545 * In the semi idle case, use the nearest busy cpu for migrating timers 546 * from an idle cpu. This is good for power-savings. 547 * 548 * We don't do similar optimization for completely idle system, as 549 * selecting an idle cpu will add more delays to the timers than intended 550 * (as that cpu's timer base may not be uptodate wrt jiffies etc). 551 */ 552int get_nohz_timer_target(void) 553{ 554 int cpu = smp_processor_id(); 555 int i; 556 struct sched_domain *sd; 557 558 rcu_read_lock(); 559 for_each_domain(cpu, sd) { 560 for_each_cpu(i, sched_domain_span(sd)) { 561 if (!idle_cpu(i)) { 562 cpu = i; 563 goto unlock; 564 } 565 } 566 } 567unlock: 568 rcu_read_unlock(); 569 return cpu; 570} 571/* 572 * When add_timer_on() enqueues a timer into the timer wheel of an 573 * idle CPU then this timer might expire before the next timer event 574 * which is scheduled to wake up that CPU. In case of a completely 575 * idle system the next event might even be infinite time into the 576 * future. wake_up_idle_cpu() ensures that the CPU is woken up and 577 * leaves the inner idle loop so the newly added timer is taken into 578 * account when the CPU goes back to idle and evaluates the timer 579 * wheel for the next timer event. 580 */ 581void wake_up_idle_cpu(int cpu) 582{ 583 struct rq *rq = cpu_rq(cpu); 584 585 if (cpu == smp_processor_id()) 586 return; 587 588 /* 589 * This is safe, as this function is called with the timer 590 * wheel base lock of (cpu) held. When the CPU is on the way 591 * to idle and has not yet set rq->curr to idle then it will 592 * be serialized on the timer wheel base lock and take the new 593 * timer into account automatically. 594 */ 595 if (rq->curr != rq->idle) 596 return; 597 598 /* 599 * We can set TIF_RESCHED on the idle task of the other CPU 600 * lockless. The worst case is that the other CPU runs the 601 * idle task through an additional NOOP schedule() 602 */ 603 set_tsk_need_resched(rq->idle); 604 605 /* NEED_RESCHED must be visible before we test polling */ 606 smp_mb(); 607 if (!tsk_is_polling(rq->idle)) 608 smp_send_reschedule(cpu); 609} 610 611static inline bool got_nohz_idle_kick(void) 612{ 613 int cpu = smp_processor_id(); 614 return idle_cpu(cpu) && test_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu)); 615} 616 617#else /* CONFIG_NO_HZ */ 618 619static inline bool got_nohz_idle_kick(void) 620{ 621 return false; 622} 623 624#endif /* CONFIG_NO_HZ */ 625 626void sched_avg_update(struct rq *rq) 627{ 628 s64 period = sched_avg_period(); 629 630 while ((s64)(rq->clock - rq->age_stamp) > period) { 631 /* 632 * Inline assembly required to prevent the compiler 633 * optimising this loop into a divmod call. 634 * See __iter_div_u64_rem() for another example of this. 635 */ 636 asm("" : "+rm" (rq->age_stamp)); 637 rq->age_stamp += period; 638 rq->rt_avg /= 2; 639 } 640} 641 642#else /* !CONFIG_SMP */ 643void resched_task(struct task_struct *p) 644{ 645 assert_raw_spin_locked(&task_rq(p)->lock); 646 set_tsk_need_resched(p); 647} 648#endif /* CONFIG_SMP */ 649 650#if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \ 651 (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH))) 652/* 653 * Iterate task_group tree rooted at *from, calling @down when first entering a 654 * node and @up when leaving it for the final time. 655 * 656 * Caller must hold rcu_lock or sufficient equivalent. 657 */ 658int walk_tg_tree_from(struct task_group *from, 659 tg_visitor down, tg_visitor up, void *data) 660{ 661 struct task_group *parent, *child; 662 int ret; 663 664 parent = from; 665 666down: 667 ret = (*down)(parent, data); 668 if (ret) 669 goto out; 670 list_for_each_entry_rcu(child, &parent->children, siblings) { 671 parent = child; 672 goto down; 673 674up: 675 continue; 676 } 677 ret = (*up)(parent, data); 678 if (ret || parent == from) 679 goto out; 680 681 child = parent; 682 parent = parent->parent; 683 if (parent) 684 goto up; 685out: 686 return ret; 687} 688 689int tg_nop(struct task_group *tg, void *data) 690{ 691 return 0; 692} 693#endif 694 695static void set_load_weight(struct task_struct *p) 696{ 697 int prio = p->static_prio - MAX_RT_PRIO; 698 struct load_weight *load = &p->se.load; 699 700 /* 701 * SCHED_IDLE tasks get minimal weight: 702 */ 703 if (p->policy == SCHED_IDLE) { 704 load->weight = scale_load(WEIGHT_IDLEPRIO); 705 load->inv_weight = WMULT_IDLEPRIO; 706 return; 707 } 708 709 load->weight = scale_load(prio_to_weight[prio]); 710 load->inv_weight = prio_to_wmult[prio]; 711} 712 713static void enqueue_task(struct rq *rq, struct task_struct *p, int flags) 714{ 715 update_rq_clock(rq); 716 sched_info_queued(p); 717 p->sched_class->enqueue_task(rq, p, flags); 718} 719 720static void dequeue_task(struct rq *rq, struct task_struct *p, int flags) 721{ 722 update_rq_clock(rq); 723 sched_info_dequeued(p); 724 p->sched_class->dequeue_task(rq, p, flags); 725} 726 727void activate_task(struct rq *rq, struct task_struct *p, int flags) 728{ 729 if (task_contributes_to_load(p)) 730 rq->nr_uninterruptible--; 731 732 enqueue_task(rq, p, flags); 733} 734 735void deactivate_task(struct rq *rq, struct task_struct *p, int flags) 736{ 737 if (task_contributes_to_load(p)) 738 rq->nr_uninterruptible++; 739 740 dequeue_task(rq, p, flags); 741} 742 743#ifdef CONFIG_IRQ_TIME_ACCOUNTING 744 745/* 746 * There are no locks covering percpu hardirq/softirq time. 747 * They are only modified in account_system_vtime, on corresponding CPU 748 * with interrupts disabled. So, writes are safe. 749 * They are read and saved off onto struct rq in update_rq_clock(). 750 * This may result in other CPU reading this CPU's irq time and can 751 * race with irq/account_system_vtime on this CPU. We would either get old 752 * or new value with a side effect of accounting a slice of irq time to wrong 753 * task when irq is in progress while we read rq->clock. That is a worthy 754 * compromise in place of having locks on each irq in account_system_time. 755 */ 756static DEFINE_PER_CPU(u64, cpu_hardirq_time); 757static DEFINE_PER_CPU(u64, cpu_softirq_time); 758 759static DEFINE_PER_CPU(u64, irq_start_time); 760static int sched_clock_irqtime; 761 762void enable_sched_clock_irqtime(void) 763{ 764 sched_clock_irqtime = 1; 765} 766 767void disable_sched_clock_irqtime(void) 768{ 769 sched_clock_irqtime = 0; 770} 771 772#ifndef CONFIG_64BIT 773static DEFINE_PER_CPU(seqcount_t, irq_time_seq); 774 775static inline void irq_time_write_begin(void) 776{ 777 __this_cpu_inc(irq_time_seq.sequence); 778 smp_wmb(); 779} 780 781static inline void irq_time_write_end(void) 782{ 783 smp_wmb(); 784 __this_cpu_inc(irq_time_seq.sequence); 785} 786 787static inline u64 irq_time_read(int cpu) 788{ 789 u64 irq_time; 790 unsigned seq; 791 792 do { 793 seq = read_seqcount_begin(&per_cpu(irq_time_seq, cpu)); 794 irq_time = per_cpu(cpu_softirq_time, cpu) + 795 per_cpu(cpu_hardirq_time, cpu); 796 } while (read_seqcount_retry(&per_cpu(irq_time_seq, cpu), seq)); 797 798 return irq_time; 799} 800#else /* CONFIG_64BIT */ 801static inline void irq_time_write_begin(void) 802{ 803} 804 805static inline void irq_time_write_end(void) 806{ 807} 808 809static inline u64 irq_time_read(int cpu) 810{ 811 return per_cpu(cpu_softirq_time, cpu) + per_cpu(cpu_hardirq_time, cpu); 812} 813#endif /* CONFIG_64BIT */ 814 815/* 816 * Called before incrementing preempt_count on {soft,}irq_enter 817 * and before decrementing preempt_count on {soft,}irq_exit. 818 */ 819void account_system_vtime(struct task_struct *curr) 820{ 821 unsigned long flags; 822 s64 delta; 823 int cpu; 824 825 if (!sched_clock_irqtime) 826 return; 827 828 local_irq_save(flags); 829 830 cpu = smp_processor_id(); 831 delta = sched_clock_cpu(cpu) - __this_cpu_read(irq_start_time); 832 __this_cpu_add(irq_start_time, delta); 833 834 irq_time_write_begin(); 835 /* 836 * We do not account for softirq time from ksoftirqd here. 837 * We want to continue accounting softirq time to ksoftirqd thread 838 * in that case, so as not to confuse scheduler with a special task 839 * that do not consume any time, but still wants to run. 840 */ 841 if (hardirq_count()) 842 __this_cpu_add(cpu_hardirq_time, delta); 843 else if (in_serving_softirq() && curr != this_cpu_ksoftirqd()) 844 __this_cpu_add(cpu_softirq_time, delta); 845 846 irq_time_write_end(); 847 local_irq_restore(flags); 848} 849EXPORT_SYMBOL_GPL(account_system_vtime); 850 851#endif /* CONFIG_IRQ_TIME_ACCOUNTING */ 852 853#ifdef CONFIG_PARAVIRT 854static inline u64 steal_ticks(u64 steal) 855{ 856 if (unlikely(steal > NSEC_PER_SEC)) 857 return div_u64(steal, TICK_NSEC); 858 859 return __iter_div_u64_rem(steal, TICK_NSEC, &steal); 860} 861#endif 862 863static void update_rq_clock_task(struct rq *rq, s64 delta) 864{ 865/* 866 * In theory, the compile should just see 0 here, and optimize out the call 867 * to sched_rt_avg_update. But I don't trust it... 868 */ 869#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) 870 s64 steal = 0, irq_delta = 0; 871#endif 872#ifdef CONFIG_IRQ_TIME_ACCOUNTING 873 irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time; 874 875 /* 876 * Since irq_time is only updated on {soft,}irq_exit, we might run into 877 * this case when a previous update_rq_clock() happened inside a 878 * {soft,}irq region. 879 * 880 * When this happens, we stop ->clock_task and only update the 881 * prev_irq_time stamp to account for the part that fit, so that a next 882 * update will consume the rest. This ensures ->clock_task is 883 * monotonic. 884 * 885 * It does however cause some slight miss-attribution of {soft,}irq 886 * time, a more accurate solution would be to update the irq_time using 887 * the current rq->clock timestamp, except that would require using 888 * atomic ops. 889 */ 890 if (irq_delta > delta) 891 irq_delta = delta; 892 893 rq->prev_irq_time += irq_delta; 894 delta -= irq_delta; 895#endif 896#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING 897 if (static_key_false((¶virt_steal_rq_enabled))) { 898 u64 st; 899 900 steal = paravirt_steal_clock(cpu_of(rq)); 901 steal -= rq->prev_steal_time_rq; 902 903 if (unlikely(steal > delta)) 904 steal = delta; 905 906 st = steal_ticks(steal); 907 steal = st * TICK_NSEC; 908 909 rq->prev_steal_time_rq += steal; 910 911 delta -= steal; 912 } 913#endif 914 915 rq->clock_task += delta; 916 917#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) 918 if ((irq_delta + steal) && sched_feat(NONTASK_POWER)) 919 sched_rt_avg_update(rq, irq_delta + steal); 920#endif 921} 922 923#ifdef CONFIG_IRQ_TIME_ACCOUNTING 924static int irqtime_account_hi_update(void) 925{ 926 u64 *cpustat = kcpustat_this_cpu->cpustat; 927 unsigned long flags; 928 u64 latest_ns; 929 int ret = 0; 930 931 local_irq_save(flags); 932 latest_ns = this_cpu_read(cpu_hardirq_time); 933 if (nsecs_to_cputime64(latest_ns) > cpustat[CPUTIME_IRQ]) 934 ret = 1; 935 local_irq_restore(flags); 936 return ret; 937} 938 939static int irqtime_account_si_update(void) 940{ 941 u64 *cpustat = kcpustat_this_cpu->cpustat; 942 unsigned long flags; 943 u64 latest_ns; 944 int ret = 0; 945 946 local_irq_save(flags); 947 latest_ns = this_cpu_read(cpu_softirq_time); 948 if (nsecs_to_cputime64(latest_ns) > cpustat[CPUTIME_SOFTIRQ]) 949 ret = 1; 950 local_irq_restore(flags); 951 return ret; 952} 953 954#else /* CONFIG_IRQ_TIME_ACCOUNTING */ 955 956#define sched_clock_irqtime (0) 957 958#endif 959 960void sched_set_stop_task(int cpu, struct task_struct *stop) 961{ 962 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 }; 963 struct task_struct *old_stop = cpu_rq(cpu)->stop; 964 965 if (stop) { 966 /* 967 * Make it appear like a SCHED_FIFO task, its something 968 * userspace knows about and won't get confused about. 969 * 970 * Also, it will make PI more or less work without too 971 * much confusion -- but then, stop work should not 972 * rely on PI working anyway. 973 */ 974 sched_setscheduler_nocheck(stop, SCHED_FIFO, ¶m); 975 976 stop->sched_class = &stop_sched_class; 977 } 978 979 cpu_rq(cpu)->stop = stop; 980 981 if (old_stop) { 982 /* 983 * Reset it back to a normal scheduling class so that 984 * it can die in pieces. 985 */ 986 old_stop->sched_class = &rt_sched_class; 987 } 988} 989 990/* 991 * __normal_prio - return the priority that is based on the static prio 992 */ 993static inline int __normal_prio(struct task_struct *p) 994{ 995 return p->static_prio; 996} 997 998/* 999 * Calculate the expected normal priority: i.e. priority 1000 * without taking RT-inheritance into account. Might be 1001 * boosted by interactivity modifiers. Changes upon fork, 1002 * setprio syscalls, and whenever the interactivity 1003 * estimator recalculates. 1004 */ 1005static inline int normal_prio(struct task_struct *p) 1006{ 1007 int prio; 1008 1009 if (task_has_rt_policy(p)) 1010 prio = MAX_RT_PRIO-1 - p->rt_priority; 1011 else 1012 prio = __normal_prio(p); 1013 return prio; 1014} 1015 1016/* 1017 * Calculate the current priority, i.e. the priority 1018 * taken into account by the scheduler. This value might 1019 * be boosted by RT tasks, or might be boosted by 1020 * interactivity modifiers. Will be RT if the task got 1021 * RT-boosted. If not then it returns p->normal_prio. 1022 */ 1023static int effective_prio(struct task_struct *p) 1024{ 1025 p->normal_prio = normal_prio(p); 1026 /* 1027 * If we are RT tasks or we were boosted to RT priority, 1028 * keep the priority unchanged. Otherwise, update priority 1029 * to the normal priority: 1030 */ 1031 if (!rt_prio(p->prio)) 1032 return p->normal_prio; 1033 return p->prio; 1034} 1035 1036/** 1037 * task_curr - is this task currently executing on a CPU? 1038 * @p: the task in question. 1039 */ 1040inline int task_curr(const struct task_struct *p) 1041{ 1042 return cpu_curr(task_cpu(p)) == p; 1043} 1044 1045static inline void check_class_changed(struct rq *rq, struct task_struct *p, 1046 const struct sched_class *prev_class, 1047 int oldprio) 1048{ 1049 if (prev_class != p->sched_class) { 1050 if (prev_class->switched_from) 1051 prev_class->switched_from(rq, p); 1052 p->sched_class->switched_to(rq, p); 1053 } else if (oldprio != p->prio) 1054 p->sched_class->prio_changed(rq, p, oldprio); 1055} 1056 1057void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags) 1058{ 1059 const struct sched_class *class; 1060 1061 if (p->sched_class == rq->curr->sched_class) { 1062 rq->curr->sched_class->check_preempt_curr(rq, p, flags); 1063 } else { 1064 for_each_class(class) { 1065 if (class == rq->curr->sched_class) 1066 break; 1067 if (class == p->sched_class) { 1068 resched_task(rq->curr); 1069 break; 1070 } 1071 } 1072 } 1073 1074 /* 1075 * A queue event has occurred, and we're going to schedule. In 1076 * this case, we can save a useless back to back clock update. 1077 */ 1078 if (rq->curr->on_rq && test_tsk_need_resched(rq->curr)) 1079 rq->skip_clock_update = 1; 1080} 1081 1082#ifdef CONFIG_SMP 1083void set_task_cpu(struct task_struct *p, unsigned int new_cpu) 1084{ 1085#ifdef CONFIG_SCHED_DEBUG 1086 /* 1087 * We should never call set_task_cpu() on a blocked task, 1088 * ttwu() will sort out the placement. 1089 */ 1090 WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING && 1091 !(task_thread_info(p)->preempt_count & PREEMPT_ACTIVE)); 1092 1093#ifdef CONFIG_LOCKDEP 1094 /* 1095 * The caller should hold either p->pi_lock or rq->lock, when changing 1096 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks. 1097 * 1098 * sched_move_task() holds both and thus holding either pins the cgroup, 1099 * see set_task_rq(). 1100 * 1101 * Furthermore, all task_rq users should acquire both locks, see 1102 * task_rq_lock(). 1103 */ 1104 WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) || 1105 lockdep_is_held(&task_rq(p)->lock))); 1106#endif 1107#endif 1108 1109 trace_sched_migrate_task(p, new_cpu); 1110 1111 if (task_cpu(p) != new_cpu) { 1112 p->se.nr_migrations++; 1113 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, 1, NULL, 0); 1114 } 1115 1116 __set_task_cpu(p, new_cpu); 1117} 1118 1119struct migration_arg { 1120 struct task_struct *task; 1121 int dest_cpu; 1122}; 1123 1124static int migration_cpu_stop(void *data); 1125 1126/* 1127 * wait_task_inactive - wait for a thread to unschedule. 1128 * 1129 * If @match_state is nonzero, it's the @p->state value just checked and 1130 * not expected to change. If it changes, i.e. @p might have woken up, 1131 * then return zero. When we succeed in waiting for @p to be off its CPU, 1132 * we return a positive number (its total switch count). If a second call 1133 * a short while later returns the same number, the caller can be sure that 1134 * @p has remained unscheduled the whole time. 1135 * 1136 * The caller must ensure that the task *will* unschedule sometime soon, 1137 * else this function might spin for a *long* time. This function can't 1138 * be called with interrupts off, or it may introduce deadlock with 1139 * smp_call_function() if an IPI is sent by the same process we are 1140 * waiting to become inactive. 1141 */ 1142unsigned long wait_task_inactive(struct task_struct *p, long match_state) 1143{ 1144 unsigned long flags; 1145 int running, on_rq; 1146 unsigned long ncsw; 1147 struct rq *rq; 1148 1149 for (;;) { 1150 /* 1151 * We do the initial early heuristics without holding 1152 * any task-queue locks at all. We'll only try to get 1153 * the runqueue lock when things look like they will 1154 * work out! 1155 */ 1156 rq = task_rq(p); 1157 1158 /* 1159 * If the task is actively running on another CPU 1160 * still, just relax and busy-wait without holding 1161 * any locks. 1162 * 1163 * NOTE! Since we don't hold any locks, it's not 1164 * even sure that "rq" stays as the right runqueue! 1165 * But we don't care, since "task_running()" will 1166 * return false if the runqueue has changed and p 1167 * is actually now running somewhere else! 1168 */ 1169 while (task_running(rq, p)) { 1170 if (match_state && unlikely(p->state != match_state)) 1171 return 0; 1172 cpu_relax(); 1173 } 1174 1175 /* 1176 * Ok, time to look more closely! We need the rq 1177 * lock now, to be *sure*. If we're wrong, we'll 1178 * just go back and repeat. 1179 */ 1180 rq = task_rq_lock(p, &flags); 1181 trace_sched_wait_task(p); 1182 running = task_running(rq, p); 1183 on_rq = p->on_rq; 1184 ncsw = 0; 1185 if (!match_state || p->state == match_state) 1186 ncsw = p->nvcsw | LONG_MIN; /* sets MSB */ 1187 task_rq_unlock(rq, p, &flags); 1188 1189 /* 1190 * If it changed from the expected state, bail out now. 1191 */ 1192 if (unlikely(!ncsw)) 1193 break; 1194 1195 /* 1196 * Was it really running after all now that we 1197 * checked with the proper locks actually held? 1198 * 1199 * Oops. Go back and try again.. 1200 */ 1201 if (unlikely(running)) { 1202 cpu_relax(); 1203 continue; 1204 } 1205 1206 /* 1207 * It's not enough that it's not actively running, 1208 * it must be off the runqueue _entirely_, and not 1209 * preempted! 1210 * 1211 * So if it was still runnable (but just not actively 1212 * running right now), it's preempted, and we should 1213 * yield - it could be a while. 1214 */ 1215 if (unlikely(on_rq)) { 1216 ktime_t to = ktime_set(0, NSEC_PER_SEC/HZ); 1217 1218 set_current_state(TASK_UNINTERRUPTIBLE); 1219 schedule_hrtimeout(&to, HRTIMER_MODE_REL); 1220 continue; 1221 } 1222 1223 /* 1224 * Ahh, all good. It wasn't running, and it wasn't 1225 * runnable, which means that it will never become 1226 * running in the future either. We're all done! 1227 */ 1228 break; 1229 } 1230 1231 return ncsw; 1232} 1233 1234/*** 1235 * kick_process - kick a running thread to enter/exit the kernel 1236 * @p: the to-be-kicked thread 1237 * 1238 * Cause a process which is running on another CPU to enter 1239 * kernel-mode, without any delay. (to get signals handled.) 1240 * 1241 * NOTE: this function doesn't have to take the runqueue lock, 1242 * because all it wants to ensure is that the remote task enters 1243 * the kernel. If the IPI races and the task has been migrated 1244 * to another CPU then no harm is done and the purpose has been 1245 * achieved as well. 1246 */ 1247void kick_process(struct task_struct *p) 1248{ 1249 int cpu; 1250 1251 preempt_disable(); 1252 cpu = task_cpu(p); 1253 if ((cpu != smp_processor_id()) && task_curr(p)) 1254 smp_send_reschedule(cpu); 1255 preempt_enable(); 1256} 1257EXPORT_SYMBOL_GPL(kick_process); 1258#endif /* CONFIG_SMP */ 1259 1260#ifdef CONFIG_SMP 1261/* 1262 * ->cpus_allowed is protected by both rq->lock and p->pi_lock 1263 */ 1264static int select_fallback_rq(int cpu, struct task_struct *p) 1265{ 1266 const struct cpumask *nodemask = cpumask_of_node(cpu_to_node(cpu)); 1267 enum { cpuset, possible, fail } state = cpuset; 1268 int dest_cpu; 1269 1270 /* Look for allowed, online CPU in same node. */ 1271 for_each_cpu(dest_cpu, nodemask) { 1272 if (!cpu_online(dest_cpu)) 1273 continue; 1274 if (!cpu_active(dest_cpu)) 1275 continue; 1276 if (cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) 1277 return dest_cpu; 1278 } 1279 1280 for (;;) { 1281 /* Any allowed, online CPU? */ 1282 for_each_cpu(dest_cpu, tsk_cpus_allowed(p)) { 1283 if (!cpu_online(dest_cpu)) 1284 continue; 1285 if (!cpu_active(dest_cpu)) 1286 continue; 1287 goto out; 1288 } 1289 1290 switch (state) { 1291 case cpuset: 1292 /* No more Mr. Nice Guy. */ 1293 cpuset_cpus_allowed_fallback(p); 1294 state = possible; 1295 break; 1296 1297 case possible: 1298 do_set_cpus_allowed(p, cpu_possible_mask); 1299 state = fail; 1300 break; 1301 1302 case fail: 1303 BUG(); 1304 break; 1305 } 1306 } 1307 1308out: 1309 if (state != cpuset) { 1310 /* 1311 * Don't tell them about moving exiting tasks or 1312 * kernel threads (both mm NULL), since they never 1313 * leave kernel. 1314 */ 1315 if (p->mm && printk_ratelimit()) { 1316 printk_sched("process %d (%s) no longer affine to cpu%d\n", 1317 task_pid_nr(p), p->comm, cpu); 1318 } 1319 } 1320 1321 return dest_cpu; 1322} 1323 1324/* 1325 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable. 1326 */ 1327static inline 1328int select_task_rq(struct task_struct *p, int sd_flags, int wake_flags) 1329{ 1330 int cpu = p->sched_class->select_task_rq(p, sd_flags, wake_flags); 1331 1332 /* 1333 * In order not to call set_task_cpu() on a blocking task we need 1334 * to rely on ttwu() to place the task on a valid ->cpus_allowed 1335 * cpu. 1336 * 1337 * Since this is common to all placement strategies, this lives here. 1338 * 1339 * [ this allows ->select_task() to simply return task_cpu(p) and 1340 * not worry about this generic constraint ] 1341 */ 1342 if (unlikely(!cpumask_test_cpu(cpu, tsk_cpus_allowed(p)) || 1343 !cpu_online(cpu))) 1344 cpu = select_fallback_rq(task_cpu(p), p); 1345 1346 return cpu; 1347} 1348 1349static void update_avg(u64 *avg, u64 sample) 1350{ 1351 s64 diff = sample - *avg; 1352 *avg += diff >> 3; 1353} 1354#endif 1355 1356static void 1357ttwu_stat(struct task_struct *p, int cpu, int wake_flags) 1358{ 1359#ifdef CONFIG_SCHEDSTATS 1360 struct rq *rq = this_rq(); 1361 1362#ifdef CONFIG_SMP 1363 int this_cpu = smp_processor_id(); 1364 1365 if (cpu == this_cpu) { 1366 schedstat_inc(rq, ttwu_local); 1367 schedstat_inc(p, se.statistics.nr_wakeups_local); 1368 } else { 1369 struct sched_domain *sd; 1370 1371 schedstat_inc(p, se.statistics.nr_wakeups_remote); 1372 rcu_read_lock(); 1373 for_each_domain(this_cpu, sd) { 1374 if (cpumask_test_cpu(cpu, sched_domain_span(sd))) { 1375 schedstat_inc(sd, ttwu_wake_remote); 1376 break; 1377 } 1378 } 1379 rcu_read_unlock(); 1380 } 1381 1382 if (wake_flags & WF_MIGRATED) 1383 schedstat_inc(p, se.statistics.nr_wakeups_migrate); 1384 1385#endif /* CONFIG_SMP */ 1386 1387 schedstat_inc(rq, ttwu_count); 1388 schedstat_inc(p, se.statistics.nr_wakeups); 1389 1390 if (wake_flags & WF_SYNC) 1391 schedstat_inc(p, se.statistics.nr_wakeups_sync); 1392 1393#endif /* CONFIG_SCHEDSTATS */ 1394} 1395 1396static void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags) 1397{ 1398 activate_task(rq, p, en_flags); 1399 p->on_rq = 1; 1400 1401 /* if a worker is waking up, notify workqueue */ 1402 if (p->flags & PF_WQ_WORKER) 1403 wq_worker_waking_up(p, cpu_of(rq)); 1404} 1405 1406/* 1407 * Mark the task runnable and perform wakeup-preemption. 1408 */ 1409static void 1410ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags) 1411{ 1412 trace_sched_wakeup(p, true); 1413 check_preempt_curr(rq, p, wake_flags); 1414 1415 p->state = TASK_RUNNING; 1416#ifdef CONFIG_SMP 1417 if (p->sched_class->task_woken) 1418 p->sched_class->task_woken(rq, p); 1419 1420 if (rq->idle_stamp) { 1421 u64 delta = rq->clock - rq->idle_stamp; 1422 u64 max = 2*sysctl_sched_migration_cost; 1423 1424 if (delta > max) 1425 rq->avg_idle = max; 1426 else 1427 update_avg(&rq->avg_idle, delta); 1428 rq->idle_stamp = 0; 1429 } 1430#endif 1431} 1432 1433static void 1434ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags) 1435{ 1436#ifdef CONFIG_SMP 1437 if (p->sched_contributes_to_load) 1438 rq->nr_uninterruptible--; 1439#endif 1440 1441 ttwu_activate(rq, p, ENQUEUE_WAKEUP | ENQUEUE_WAKING); 1442 ttwu_do_wakeup(rq, p, wake_flags); 1443} 1444 1445/* 1446 * Called in case the task @p isn't fully descheduled from its runqueue, 1447 * in this case we must do a remote wakeup. Its a 'light' wakeup though, 1448 * since all we need to do is flip p->state to TASK_RUNNING, since 1449 * the task is still ->on_rq. 1450 */ 1451static int ttwu_remote(struct task_struct *p, int wake_flags) 1452{ 1453 struct rq *rq; 1454 int ret = 0; 1455 1456 rq = __task_rq_lock(p); 1457 if (p->on_rq) { 1458 ttwu_do_wakeup(rq, p, wake_flags); 1459 ret = 1; 1460 } 1461 __task_rq_unlock(rq); 1462 1463 return ret; 1464} 1465 1466#ifdef CONFIG_SMP 1467static void sched_ttwu_pending(void) 1468{ 1469 struct rq *rq = this_rq(); 1470 struct llist_node *llist = llist_del_all(&rq->wake_list); 1471 struct task_struct *p; 1472 1473 raw_spin_lock(&rq->lock); 1474 1475 while (llist) { 1476 p = llist_entry(llist, struct task_struct, wake_entry); 1477 llist = llist_next(llist); 1478 ttwu_do_activate(rq, p, 0); 1479 } 1480 1481 raw_spin_unlock(&rq->lock); 1482} 1483 1484void scheduler_ipi(void) 1485{ 1486 if (llist_empty(&this_rq()->wake_list) && !got_nohz_idle_kick()) 1487 return; 1488 1489 /* 1490 * Not all reschedule IPI handlers call irq_enter/irq_exit, since 1491 * traditionally all their work was done from the interrupt return 1492 * path. Now that we actually do some work, we need to make sure 1493 * we do call them. 1494 * 1495 * Some archs already do call them, luckily irq_enter/exit nest 1496 * properly. 1497 * 1498 * Arguably we should visit all archs and update all handlers, 1499 * however a fair share of IPIs are still resched only so this would 1500 * somewhat pessimize the simple resched case. 1501 */ 1502 irq_enter(); 1503 sched_ttwu_pending(); 1504 1505 /* 1506 * Check if someone kicked us for doing the nohz idle load balance. 1507 */ 1508 if (unlikely(got_nohz_idle_kick() && !need_resched())) { 1509 this_rq()->idle_balance = 1; 1510 raise_softirq_irqoff(SCHED_SOFTIRQ); 1511 } 1512 irq_exit(); 1513} 1514 1515static void ttwu_queue_remote(struct task_struct *p, int cpu) 1516{ 1517 if (llist_add(&p->wake_entry, &cpu_rq(cpu)->wake_list)) 1518 smp_send_reschedule(cpu); 1519} 1520 1521#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW 1522static int ttwu_activate_remote(struct task_struct *p, int wake_flags) 1523{ 1524 struct rq *rq; 1525 int ret = 0; 1526 1527 rq = __task_rq_lock(p); 1528 if (p->on_cpu) { 1529 ttwu_activate(rq, p, ENQUEUE_WAKEUP); 1530 ttwu_do_wakeup(rq, p, wake_flags); 1531 ret = 1; 1532 } 1533 __task_rq_unlock(rq); 1534 1535 return ret; 1536 1537} 1538#endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */ 1539 1540bool cpus_share_cache(int this_cpu, int that_cpu) 1541{ 1542 return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu); 1543} 1544#endif /* CONFIG_SMP */ 1545 1546static void ttwu_queue(struct task_struct *p, int cpu) 1547{ 1548 struct rq *rq = cpu_rq(cpu); 1549 1550#if defined(CONFIG_SMP) 1551 if (sched_feat(TTWU_QUEUE) && !cpus_share_cache(smp_processor_id(), cpu)) { 1552 sched_clock_cpu(cpu); /* sync clocks x-cpu */ 1553 ttwu_queue_remote(p, cpu); 1554 return; 1555 } 1556#endif 1557 1558 raw_spin_lock(&rq->lock); 1559 ttwu_do_activate(rq, p, 0); 1560 raw_spin_unlock(&rq->lock); 1561} 1562 1563/** 1564 * try_to_wake_up - wake up a thread 1565 * @p: the thread to be awakened 1566 * @state: the mask of task states that can be woken 1567 * @wake_flags: wake modifier flags (WF_*) 1568 * 1569 * Put it on the run-queue if it's not already there. The "current" 1570 * thread is always on the run-queue (except when the actual 1571 * re-schedule is in progress), and as such you're allowed to do 1572 * the simpler "current->state = TASK_RUNNING" to mark yourself 1573 * runnable without the overhead of this. 1574 * 1575 * Returns %true if @p was woken up, %false if it was already running 1576 * or @state didn't match @p's state. 1577 */ 1578static int 1579try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) 1580{ 1581 unsigned long flags; 1582 int cpu, success = 0; 1583 1584 smp_wmb(); 1585 raw_spin_lock_irqsave(&p->pi_lock, flags); 1586 if (!(p->state & state)) 1587 goto out; 1588 1589 success = 1; /* we're going to change ->state */ 1590 cpu = task_cpu(p); 1591 1592 if (p->on_rq && ttwu_remote(p, wake_flags)) 1593 goto stat; 1594 1595#ifdef CONFIG_SMP 1596 /* 1597 * If the owning (remote) cpu is still in the middle of schedule() with 1598 * this task as prev, wait until its done referencing the task. 1599 */ 1600 while (p->on_cpu) { 1601#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW 1602 /* 1603 * In case the architecture enables interrupts in 1604 * context_switch(), we cannot busy wait, since that 1605 * would lead to deadlocks when an interrupt hits and 1606 * tries to wake up @prev. So bail and do a complete 1607 * remote wakeup. 1608 */ 1609 if (ttwu_activate_remote(p, wake_flags)) 1610 goto stat; 1611#else 1612 cpu_relax(); 1613#endif 1614 } 1615 /* 1616 * Pairs with the smp_wmb() in finish_lock_switch(). 1617 */ 1618 smp_rmb(); 1619 1620 p->sched_contributes_to_load = !!task_contributes_to_load(p); 1621 p->state = TASK_WAKING; 1622 1623 if (p->sched_class->task_waking) 1624 p->sched_class->task_waking(p); 1625 1626 cpu = select_task_rq(p, SD_BALANCE_WAKE, wake_flags); 1627 if (task_cpu(p) != cpu) { 1628 wake_flags |= WF_MIGRATED; 1629 set_task_cpu(p, cpu); 1630 } 1631#endif /* CONFIG_SMP */ 1632 1633 ttwu_queue(p, cpu); 1634stat: 1635 ttwu_stat(p, cpu, wake_flags); 1636out: 1637 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 1638 1639 return success; 1640} 1641 1642/** 1643 * try_to_wake_up_local - try to wake up a local task with rq lock held 1644 * @p: the thread to be awakened 1645 * 1646 * Put @p on the run-queue if it's not already there. The caller must 1647 * ensure that this_rq() is locked, @p is bound to this_rq() and not 1648 * the current task. 1649 */ 1650static void try_to_wake_up_local(struct task_struct *p) 1651{ 1652 struct rq *rq = task_rq(p); 1653 1654 BUG_ON(rq != this_rq()); 1655 BUG_ON(p == current); 1656 lockdep_assert_held(&rq->lock); 1657 1658 if (!raw_spin_trylock(&p->pi_lock)) { 1659 raw_spin_unlock(&rq->lock); 1660 raw_spin_lock(&p->pi_lock); 1661 raw_spin_lock(&rq->lock); 1662 } 1663 1664 if (!(p->state & TASK_NORMAL)) 1665 goto out; 1666 1667 if (!p->on_rq) 1668 ttwu_activate(rq, p, ENQUEUE_WAKEUP); 1669 1670 ttwu_do_wakeup(rq, p, 0); 1671 ttwu_stat(p, smp_processor_id(), 0); 1672out: 1673 raw_spin_unlock(&p->pi_lock); 1674} 1675 1676/** 1677 * wake_up_process - Wake up a specific process 1678 * @p: The process to be woken up. 1679 * 1680 * Attempt to wake up the nominated process and move it to the set of runnable 1681 * processes. Returns 1 if the process was woken up, 0 if it was already 1682 * running. 1683 * 1684 * It may be assumed that this function implies a write memory barrier before 1685 * changing the task state if and only if any tasks are woken up. 1686 */ 1687int wake_up_process(struct task_struct *p) 1688{ 1689 return try_to_wake_up(p, TASK_ALL, 0); 1690} 1691EXPORT_SYMBOL(wake_up_process); 1692 1693int wake_up_state(struct task_struct *p, unsigned int state) 1694{ 1695 return try_to_wake_up(p, state, 0); 1696} 1697 1698/* 1699 * Perform scheduler related setup for a newly forked process p. 1700 * p is forked by current. 1701 * 1702 * __sched_fork() is basic setup used by init_idle() too: 1703 */ 1704static void __sched_fork(struct task_struct *p) 1705{ 1706 p->on_rq = 0; 1707 1708 p->se.on_rq = 0; 1709 p->se.exec_start = 0; 1710 p->se.sum_exec_runtime = 0; 1711 p->se.prev_sum_exec_runtime = 0; 1712 p->se.nr_migrations = 0; 1713 p->se.vruntime = 0; 1714 INIT_LIST_HEAD(&p->se.group_node); 1715 1716#ifdef CONFIG_SCHEDSTATS 1717 memset(&p->se.statistics, 0, sizeof(p->se.statistics)); 1718#endif 1719 1720 INIT_LIST_HEAD(&p->rt.run_list); 1721 1722#ifdef CONFIG_PREEMPT_NOTIFIERS 1723 INIT_HLIST_HEAD(&p->preempt_notifiers); 1724#endif 1725} 1726 1727/* 1728 * fork()/clone()-time setup: 1729 */ 1730void sched_fork(struct task_struct *p) 1731{ 1732 unsigned long flags; 1733 int cpu = get_cpu(); 1734 1735 __sched_fork(p); 1736 /* 1737 * We mark the process as running here. This guarantees that 1738 * nobody will actually run it, and a signal or other external 1739 * event cannot wake it up and insert it on the runqueue either. 1740 */ 1741 p->state = TASK_RUNNING; 1742 1743 /* 1744 * Make sure we do not leak PI boosting priority to the child. 1745 */ 1746 p->prio = current->normal_prio; 1747 1748 /* 1749 * Revert to default priority/policy on fork if requested. 1750 */ 1751 if (unlikely(p->sched_reset_on_fork)) { 1752 if (task_has_rt_policy(p)) { 1753 p->policy = SCHED_NORMAL; 1754 p->static_prio = NICE_TO_PRIO(0); 1755 p->rt_priority = 0; 1756 } else if (PRIO_TO_NICE(p->static_prio) < 0) 1757 p->static_prio = NICE_TO_PRIO(0); 1758 1759 p->prio = p->normal_prio = __normal_prio(p); 1760 set_load_weight(p); 1761 1762 /* 1763 * We don't need the reset flag anymore after the fork. It has 1764 * fulfilled its duty: 1765 */ 1766 p->sched_reset_on_fork = 0; 1767 } 1768 1769 if (!rt_prio(p->prio)) 1770 p->sched_class = &fair_sched_class; 1771 1772 if (p->sched_class->task_fork) 1773 p->sched_class->task_fork(p); 1774 1775 /* 1776 * The child is not yet in the pid-hash so no cgroup attach races, 1777 * and the cgroup is pinned to this child due to cgroup_fork() 1778 * is ran before sched_fork(). 1779 * 1780 * Silence PROVE_RCU. 1781 */ 1782 raw_spin_lock_irqsave(&p->pi_lock, flags); 1783 set_task_cpu(p, cpu); 1784 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 1785 1786#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) 1787 if (likely(sched_info_on())) 1788 memset(&p->sched_info, 0, sizeof(p->sched_info)); 1789#endif 1790#if defined(CONFIG_SMP) 1791 p->on_cpu = 0; 1792#endif 1793#ifdef CONFIG_PREEMPT_COUNT 1794 /* Want to start with kernel preemption disabled. */ 1795 task_thread_info(p)->preempt_count = 1; 1796#endif 1797#ifdef CONFIG_SMP 1798 plist_node_init(&p->pushable_tasks, MAX_PRIO); 1799#endif 1800 1801 put_cpu(); 1802} 1803 1804/* 1805 * wake_up_new_task - wake up a newly created task for the first time. 1806 * 1807 * This function will do some initial scheduler statistics housekeeping 1808 * that must be done for every newly created context, then puts the task 1809 * on the runqueue and wakes it. 1810 */ 1811void wake_up_new_task(struct task_struct *p) 1812{ 1813 unsigned long flags; 1814 struct rq *rq; 1815 1816 raw_spin_lock_irqsave(&p->pi_lock, flags); 1817#ifdef CONFIG_SMP 1818 /* 1819 * Fork balancing, do it here and not earlier because: 1820 * - cpus_allowed can change in the fork path 1821 * - any previously selected cpu might disappear through hotplug 1822 */ 1823 set_task_cpu(p, select_task_rq(p, SD_BALANCE_FORK, 0)); 1824#endif 1825 1826 rq = __task_rq_lock(p); 1827 activate_task(rq, p, 0); 1828 p->on_rq = 1; 1829 trace_sched_wakeup_new(p, true); 1830 check_preempt_curr(rq, p, WF_FORK); 1831#ifdef CONFIG_SMP 1832 if (p->sched_class->task_woken) 1833 p->sched_class->task_woken(rq, p); 1834#endif 1835 task_rq_unlock(rq, p, &flags); 1836} 1837 1838#ifdef CONFIG_PREEMPT_NOTIFIERS 1839 1840/** 1841 * preempt_notifier_register - tell me when current is being preempted & rescheduled 1842 * @notifier: notifier struct to register 1843 */ 1844void preempt_notifier_register(struct preempt_notifier *notifier) 1845{ 1846 hlist_add_head(¬ifier->link, ¤t->preempt_notifiers); 1847} 1848EXPORT_SYMBOL_GPL(preempt_notifier_register); 1849 1850/** 1851 * preempt_notifier_unregister - no longer interested in preemption notifications 1852 * @notifier: notifier struct to unregister 1853 * 1854 * This is safe to call from within a preemption notifier. 1855 */ 1856void preempt_notifier_unregister(struct preempt_notifier *notifier) 1857{ 1858 hlist_del(¬ifier->link); 1859} 1860EXPORT_SYMBOL_GPL(preempt_notifier_unregister); 1861 1862static void fire_sched_in_preempt_notifiers(struct task_struct *curr) 1863{ 1864 struct preempt_notifier *notifier; 1865 struct hlist_node *node; 1866 1867 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link) 1868 notifier->ops->sched_in(notifier, raw_smp_processor_id()); 1869} 1870 1871static void 1872fire_sched_out_preempt_notifiers(struct task_struct *curr, 1873 struct task_struct *next) 1874{ 1875 struct preempt_notifier *notifier; 1876 struct hlist_node *node; 1877 1878 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link) 1879 notifier->ops->sched_out(notifier, next); 1880} 1881 1882#else /* !CONFIG_PREEMPT_NOTIFIERS */ 1883 1884static void fire_sched_in_preempt_notifiers(struct task_struct *curr) 1885{ 1886} 1887 1888static void 1889fire_sched_out_preempt_notifiers(struct task_struct *curr, 1890 struct task_struct *next) 1891{ 1892} 1893 1894#endif /* CONFIG_PREEMPT_NOTIFIERS */ 1895 1896/** 1897 * prepare_task_switch - prepare to switch tasks 1898 * @rq: the runqueue preparing to switch 1899 * @prev: the current task that is being switched out 1900 * @next: the task we are going to switch to. 1901 * 1902 * This is called with the rq lock held and interrupts off. It must 1903 * be paired with a subsequent finish_task_switch after the context 1904 * switch. 1905 * 1906 * prepare_task_switch sets up locking and calls architecture specific 1907 * hooks. 1908 */ 1909static inline void 1910prepare_task_switch(struct rq *rq, struct task_struct *prev, 1911 struct task_struct *next) 1912{ 1913 trace_sched_switch(prev, next); 1914 sched_info_switch(prev, next); 1915 perf_event_task_sched_out(prev, next); 1916 fire_sched_out_preempt_notifiers(prev, next); 1917 prepare_lock_switch(rq, next); 1918 prepare_arch_switch(next); 1919} 1920 1921/** 1922 * finish_task_switch - clean up after a task-switch 1923 * @rq: runqueue associated with task-switch 1924 * @prev: the thread we just switched away from. 1925 * 1926 * finish_task_switch must be called after the context switch, paired 1927 * with a prepare_task_switch call before the context switch. 1928 * finish_task_switch will reconcile locking set up by prepare_task_switch, 1929 * and do any other architecture-specific cleanup actions. 1930 * 1931 * Note that we may have delayed dropping an mm in context_switch(). If 1932 * so, we finish that here outside of the runqueue lock. (Doing it 1933 * with the lock held can cause deadlocks; see schedule() for 1934 * details.) 1935 */ 1936static void finish_task_switch(struct rq *rq, struct task_struct *prev) 1937 __releases(rq->lock) 1938{ 1939 struct mm_struct *mm = rq->prev_mm; 1940 long prev_state; 1941 1942 rq->prev_mm = NULL; 1943 1944 /* 1945 * A task struct has one reference for the use as "current". 1946 * If a task dies, then it sets TASK_DEAD in tsk->state and calls 1947 * schedule one last time. The schedule call will never return, and 1948 * the scheduled task must drop that reference. 1949 * The test for TASK_DEAD must occur while the runqueue locks are 1950 * still held, otherwise prev could be scheduled on another cpu, die 1951 * there before we look at prev->state, and then the reference would 1952 * be dropped twice. 1953 * Manfred Spraul <manfred@colorfullife.com> 1954 */ 1955 prev_state = prev->state; 1956 finish_arch_switch(prev); 1957#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW 1958 local_irq_disable(); 1959#endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */ 1960 perf_event_task_sched_in(prev, current); 1961#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW 1962 local_irq_enable(); 1963#endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */ 1964 finish_lock_switch(rq, prev); 1965 finish_arch_post_lock_switch(); 1966 1967 fire_sched_in_preempt_notifiers(current); 1968 if (mm) 1969 mmdrop(mm); 1970 if (unlikely(prev_state == TASK_DEAD)) { 1971 /* 1972 * Remove function-return probe instances associated with this 1973 * task and put them back on the free list. 1974 */ 1975 kprobe_flush_task(prev); 1976 put_task_struct(prev); 1977 } 1978} 1979 1980#ifdef CONFIG_SMP 1981 1982/* assumes rq->lock is held */ 1983static inline void pre_schedule(struct rq *rq, struct task_struct *prev) 1984{ 1985 if (prev->sched_class->pre_schedule) 1986 prev->sched_class->pre_schedule(rq, prev); 1987} 1988 1989/* rq->lock is NOT held, but preemption is disabled */ 1990static inline void post_schedule(struct rq *rq) 1991{ 1992 if (rq->post_schedule) { 1993 unsigned long flags; 1994 1995 raw_spin_lock_irqsave(&rq->lock, flags); 1996 if (rq->curr->sched_class->post_schedule) 1997 rq->curr->sched_class->post_schedule(rq); 1998 raw_spin_unlock_irqrestore(&rq->lock, flags); 1999 2000 rq->post_schedule = 0; 2001 } 2002} 2003 2004#else 2005 2006static inline void pre_schedule(struct rq *rq, struct task_struct *p) 2007{ 2008} 2009 2010static inline void post_schedule(struct rq *rq) 2011{ 2012} 2013 2014#endif 2015 2016/** 2017 * schedule_tail - first thing a freshly forked thread must call. 2018 * @prev: the thread we just switched away from. 2019 */ 2020asmlinkage void schedule_tail(struct task_struct *prev) 2021 __releases(rq->lock) 2022{ 2023 struct rq *rq = this_rq(); 2024 2025 finish_task_switch(rq, prev); 2026 2027 /* 2028 * FIXME: do we need to worry about rq being invalidated by the 2029 * task_switch? 2030 */ 2031 post_schedule(rq); 2032 2033#ifdef __ARCH_WANT_UNLOCKED_CTXSW 2034 /* In this case, finish_task_switch does not reenable preemption */ 2035 preempt_enable(); 2036#endif 2037 if (current->set_child_tid) 2038 put_user(task_pid_vnr(current), current->set_child_tid); 2039} 2040 2041/* 2042 * context_switch - switch to the new MM and the new 2043 * thread's register state. 2044 */ 2045static inline void 2046context_switch(struct rq *rq, struct task_struct *prev, 2047 struct task_struct *next) 2048{ 2049 struct mm_struct *mm, *oldmm; 2050 2051 prepare_task_switch(rq, prev, next); 2052 2053 mm = next->mm; 2054 oldmm = prev->active_mm; 2055 /* 2056 * For paravirt, this is coupled with an exit in switch_to to 2057 * combine the page table reload and the switch backend into 2058 * one hypercall. 2059 */ 2060 arch_start_context_switch(prev); 2061 2062 if (!mm) { 2063 next->active_mm = oldmm; 2064 atomic_inc(&oldmm->mm_count); 2065 enter_lazy_tlb(oldmm, next); 2066 } else 2067 switch_mm(oldmm, mm, next); 2068 2069 if (!prev->mm) { 2070 prev->active_mm = NULL; 2071 rq->prev_mm = oldmm; 2072 } 2073 /* 2074 * Since the runqueue lock will be released by the next 2075 * task (which is an invalid locking op but in the case 2076 * of the scheduler it's an obvious special-case), so we 2077 * do an early lockdep release here: 2078 */ 2079#ifndef __ARCH_WANT_UNLOCKED_CTXSW 2080 spin_release(&rq->lock.dep_map, 1, _THIS_IP_); 2081#endif 2082 2083 /* Here we just switch the register state and the stack. */ 2084 switch_to(prev, next, prev); 2085 2086 barrier(); 2087 /* 2088 * this_rq must be evaluated again because prev may have moved 2089 * CPUs since it called schedule(), thus the 'rq' on its stack 2090 * frame will be invalid. 2091 */ 2092 finish_task_switch(this_rq(), prev); 2093} 2094 2095/* 2096 * nr_running, nr_uninterruptible and nr_context_switches: 2097 * 2098 * externally visible scheduler statistics: current number of runnable 2099 * threads, current number of uninterruptible-sleeping threads, total 2100 * number of context switches performed since bootup. 2101 */ 2102unsigned long nr_running(void) 2103{ 2104 unsigned long i, sum = 0; 2105 2106 for_each_online_cpu(i) 2107 sum += cpu_rq(i)->nr_running; 2108 2109 return sum; 2110} 2111 2112unsigned long nr_uninterruptible(void) 2113{ 2114 unsigned long i, sum = 0; 2115 2116 for_each_possible_cpu(i) 2117 sum += cpu_rq(i)->nr_uninterruptible; 2118 2119 /* 2120 * Since we read the counters lockless, it might be slightly 2121 * inaccurate. Do not allow it to go below zero though: 2122 */ 2123 if (unlikely((long)sum < 0)) 2124 sum = 0; 2125 2126 return sum; 2127} 2128 2129unsigned long long nr_context_switches(void) 2130{ 2131 int i; 2132 unsigned long long sum = 0; 2133 2134 for_each_possible_cpu(i) 2135 sum += cpu_rq(i)->nr_switches; 2136 2137 return sum; 2138} 2139 2140unsigned long nr_iowait(void) 2141{ 2142 unsigned long i, sum = 0; 2143 2144 for_each_possible_cpu(i) 2145 sum += atomic_read(&cpu_rq(i)->nr_iowait); 2146 2147 return sum; 2148} 2149 2150unsigned long nr_iowait_cpu(int cpu) 2151{ 2152 struct rq *this = cpu_rq(cpu); 2153 return atomic_read(&this->nr_iowait); 2154} 2155 2156unsigned long this_cpu_load(void) 2157{ 2158 struct rq *this = this_rq(); 2159 return this->cpu_load[0]; 2160} 2161 2162 2163/* 2164 * Global load-average calculations 2165 * 2166 * We take a distributed and async approach to calculating the global load-avg 2167 * in order to minimize overhead. 2168 * 2169 * The global load average is an exponentially decaying average of nr_running + 2170 * nr_uninterruptible. 2171 * 2172 * Once every LOAD_FREQ: 2173 * 2174 * nr_active = 0; 2175 * for_each_possible_cpu(cpu) 2176 * nr_active += cpu_of(cpu)->nr_running + cpu_of(cpu)->nr_uninterruptible; 2177 * 2178 * avenrun[n] = avenrun[0] * exp_n + nr_active * (1 - exp_n) 2179 * 2180 * Due to a number of reasons the above turns in the mess below: 2181 * 2182 * - for_each_possible_cpu() is prohibitively expensive on machines with 2183 * serious number of cpus, therefore we need to take a distributed approach 2184 * to calculating nr_active. 2185 * 2186 * \Sum_i x_i(t) = \Sum_i x_i(t) - x_i(t_0) | x_i(t_0) := 0 2187 * = \Sum_i { \Sum_j=1 x_i(t_j) - x_i(t_j-1) } 2188 * 2189 * So assuming nr_active := 0 when we start out -- true per definition, we 2190 * can simply take per-cpu deltas and fold those into a global accumulate 2191 * to obtain the same result. See calc_load_fold_active(). 2192 * 2193 * Furthermore, in order to avoid synchronizing all per-cpu delta folding 2194 * across the machine, we assume 10 ticks is sufficient time for every 2195 * cpu to have completed this task. 2196 * 2197 * This places an upper-bound on the IRQ-off latency of the machine. Then 2198 * again, being late doesn't loose the delta, just wrecks the sample. 2199 * 2200 * - cpu_rq()->nr_uninterruptible isn't accurately tracked per-cpu because 2201 * this would add another cross-cpu cacheline miss and atomic operation 2202 * to the wakeup path. Instead we increment on whatever cpu the task ran 2203 * when it went into uninterruptible state and decrement on whatever cpu 2204 * did the wakeup. This means that only the sum of nr_uninterruptible over 2205 * all cpus yields the correct result. 2206 * 2207 * This covers the NO_HZ=n code, for extra head-aches, see the comment below. 2208 */ 2209 2210/* Variables and functions for calc_load */ 2211static atomic_long_t calc_load_tasks; 2212static unsigned long calc_load_update; 2213unsigned long avenrun[3]; 2214EXPORT_SYMBOL(avenrun); /* should be removed */ 2215 2216/** 2217 * get_avenrun - get the load average array 2218 * @loads: pointer to dest load array 2219 * @offset: offset to add 2220 * @shift: shift count to shift the result left 2221 * 2222 * These values are estimates at best, so no need for locking. 2223 */ 2224void get_avenrun(unsigned long *loads, unsigned long offset, int shift) 2225{ 2226 loads[0] = (avenrun[0] + offset) << shift; 2227 loads[1] = (avenrun[1] + offset) << shift; 2228 loads[2] = (avenrun[2] + offset) << shift; 2229} 2230 2231static long calc_load_fold_active(struct rq *this_rq) 2232{ 2233 long nr_active, delta = 0; 2234 2235 nr_active = this_rq->nr_running; 2236 nr_active += (long) this_rq->nr_uninterruptible; 2237 2238 if (nr_active != this_rq->calc_load_active) { 2239 delta = nr_active - this_rq->calc_load_active; 2240 this_rq->calc_load_active = nr_active; 2241 } 2242 2243 return delta; 2244} 2245 2246/* 2247 * a1 = a0 * e + a * (1 - e) 2248 */ 2249static unsigned long 2250calc_load(unsigned long load, unsigned long exp, unsigned long active) 2251{ 2252 load *= exp; 2253 load += active * (FIXED_1 - exp); 2254 load += 1UL << (FSHIFT - 1); 2255 return load >> FSHIFT; 2256} 2257 2258#ifdef CONFIG_NO_HZ 2259/* 2260 * Handle NO_HZ for the global load-average. 2261 * 2262 * Since the above described distributed algorithm to compute the global 2263 * load-average relies on per-cpu sampling from the tick, it is affected by 2264 * NO_HZ. 2265 * 2266 * The basic idea is to fold the nr_active delta into a global idle-delta upon 2267 * entering NO_HZ state such that we can include this as an 'extra' cpu delta 2268 * when we read the global state. 2269 * 2270 * Obviously reality has to ruin such a delightfully simple scheme: 2271 * 2272 * - When we go NO_HZ idle during the window, we can negate our sample 2273 * contribution, causing under-accounting. 2274 * 2275 * We avoid this by keeping two idle-delta counters and flipping them 2276 * when the window starts, thus separating old and new NO_HZ load. 2277 * 2278 * The only trick is the slight shift in index flip for read vs write. 2279 * 2280 * 0s 5s 10s 15s 2281 * +10 +10 +10 +10 2282 * |-|-----------|-|-----------|-|-----------|-| 2283 * r:0 0 1 1 0 0 1 1 0 2284 * w:0 1 1 0 0 1 1 0 0 2285 * 2286 * This ensures we'll fold the old idle contribution in this window while 2287 * accumlating the new one. 2288 * 2289 * - When we wake up from NO_HZ idle during the window, we push up our 2290 * contribution, since we effectively move our sample point to a known 2291 * busy state. 2292 * 2293 * This is solved by pushing the window forward, and thus skipping the 2294 * sample, for this cpu (effectively using the idle-delta for this cpu which 2295 * was in effect at the time the window opened). This also solves the issue 2296 * of having to deal with a cpu having been in NOHZ idle for multiple 2297 * LOAD_FREQ intervals. 2298 * 2299 * When making the ILB scale, we should try to pull this in as well. 2300 */ 2301static atomic_long_t calc_load_idle[2]; 2302static int calc_load_idx; 2303 2304static inline int calc_load_write_idx(void) 2305{ 2306 int idx = calc_load_idx; 2307 2308 /* 2309 * See calc_global_nohz(), if we observe the new index, we also 2310 * need to observe the new update time. 2311 */ 2312 smp_rmb(); 2313 2314 /* 2315 * If the folding window started, make sure we start writing in the 2316 * next idle-delta. 2317 */ 2318 if (!time_before(jiffies, calc_load_update)) 2319 idx++; 2320 2321 return idx & 1; 2322} 2323 2324static inline int calc_load_read_idx(void) 2325{ 2326 return calc_load_idx & 1; 2327} 2328 2329void calc_load_enter_idle(void) 2330{ 2331 struct rq *this_rq = this_rq(); 2332 long delta; 2333 2334 /* 2335 * We're going into NOHZ mode, if there's any pending delta, fold it 2336 * into the pending idle delta. 2337 */ 2338 delta = calc_load_fold_active(this_rq); 2339 if (delta) { 2340 int idx = calc_load_write_idx(); 2341 atomic_long_add(delta, &calc_load_idle[idx]); 2342 } 2343} 2344 2345void calc_load_exit_idle(void) 2346{ 2347 struct rq *this_rq = this_rq(); 2348 2349 /* 2350 * If we're still before the sample window, we're done. 2351 */ 2352 if (time_before(jiffies, this_rq->calc_load_update)) 2353 return; 2354 2355 /* 2356 * We woke inside or after the sample window, this means we're already 2357 * accounted through the nohz accounting, so skip the entire deal and 2358 * sync up for the next window. 2359 */ 2360 this_rq->calc_load_update = calc_load_update; 2361 if (time_before(jiffies, this_rq->calc_load_update + 10)) 2362 this_rq->calc_load_update += LOAD_FREQ; 2363} 2364 2365static long calc_load_fold_idle(void) 2366{ 2367 int idx = calc_load_read_idx(); 2368 long delta = 0; 2369 2370 if (atomic_long_read(&calc_load_idle[idx])) 2371 delta = atomic_long_xchg(&calc_load_idle[idx], 0); 2372 2373 return delta; 2374} 2375 2376/** 2377 * fixed_power_int - compute: x^n, in O(log n) time 2378 * 2379 * @x: base of the power 2380 * @frac_bits: fractional bits of @x 2381 * @n: power to raise @x to. 2382 * 2383 * By exploiting the relation between the definition of the natural power 2384 * function: x^n := x*x*...*x (x multiplied by itself for n times), and 2385 * the binary encoding of numbers used by computers: n := \Sum n_i * 2^i, 2386 * (where: n_i \elem {0, 1}, the binary vector representing n), 2387 * we find: x^n := x^(\Sum n_i * 2^i) := \Prod x^(n_i * 2^i), which is 2388 * of course trivially computable in O(log_2 n), the length of our binary 2389 * vector. 2390 */ 2391static unsigned long 2392fixed_power_int(unsigned long x, unsigned int frac_bits, unsigned int n) 2393{ 2394 unsigned long result = 1UL << frac_bits; 2395 2396 if (n) for (;;) { 2397 if (n & 1) { 2398 result *= x; 2399 result += 1UL << (frac_bits - 1); 2400 result >>= frac_bits; 2401 } 2402 n >>= 1; 2403 if (!n) 2404 break; 2405 x *= x; 2406 x += 1UL << (frac_bits - 1); 2407 x >>= frac_bits; 2408 } 2409 2410 return result; 2411} 2412 2413/* 2414 * a1 = a0 * e + a * (1 - e) 2415 * 2416 * a2 = a1 * e + a * (1 - e) 2417 * = (a0 * e + a * (1 - e)) * e + a * (1 - e) 2418 * = a0 * e^2 + a * (1 - e) * (1 + e) 2419 * 2420 * a3 = a2 * e + a * (1 - e) 2421 * = (a0 * e^2 + a * (1 - e) * (1 + e)) * e + a * (1 - e) 2422 * = a0 * e^3 + a * (1 - e) * (1 + e + e^2) 2423 * 2424 * ... 2425 * 2426 * an = a0 * e^n + a * (1 - e) * (1 + e + ... + e^n-1) [1] 2427 * = a0 * e^n + a * (1 - e) * (1 - e^n)/(1 - e) 2428 * = a0 * e^n + a * (1 - e^n) 2429 * 2430 * [1] application of the geometric series: 2431 * 2432 * n 1 - x^(n+1) 2433 * S_n := \Sum x^i = ------------- 2434 * i=0 1 - x 2435 */ 2436static unsigned long 2437calc_load_n(unsigned long load, unsigned long exp, 2438 unsigned long active, unsigned int n) 2439{ 2440 2441 return calc_load(load, fixed_power_int(exp, FSHIFT, n), active); 2442} 2443 2444/* 2445 * NO_HZ can leave us missing all per-cpu ticks calling 2446 * calc_load_account_active(), but since an idle CPU folds its delta into 2447 * calc_load_tasks_idle per calc_load_account_idle(), all we need to do is fold 2448 * in the pending idle delta if our idle period crossed a load cycle boundary. 2449 * 2450 * Once we've updated the global active value, we need to apply the exponential 2451 * weights adjusted to the number of cycles missed. 2452 */ 2453static void calc_global_nohz(void) 2454{ 2455 long delta, active, n; 2456 2457 if (!time_before(jiffies, calc_load_update + 10)) { 2458 /* 2459 * Catch-up, fold however many we are behind still 2460 */ 2461 delta = jiffies - calc_load_update - 10; 2462 n = 1 + (delta / LOAD_FREQ); 2463 2464 active = atomic_long_read(&calc_load_tasks); 2465 active = active > 0 ? active * FIXED_1 : 0; 2466 2467 avenrun[0] = calc_load_n(avenrun[0], EXP_1, active, n); 2468 avenrun[1] = calc_load_n(avenrun[1], EXP_5, active, n); 2469 avenrun[2] = calc_load_n(avenrun[2], EXP_15, active, n); 2470 2471 calc_load_update += n * LOAD_FREQ; 2472 } 2473 2474 /* 2475 * Flip the idle index... 2476 * 2477 * Make sure we first write the new time then flip the index, so that 2478 * calc_load_write_idx() will see the new time when it reads the new 2479 * index, this avoids a double flip messing things up. 2480 */ 2481 smp_wmb(); 2482 calc_load_idx++; 2483} 2484#else /* !CONFIG_NO_HZ */ 2485 2486static inline long calc_load_fold_idle(void) { return 0; } 2487static inline void calc_global_nohz(void) { } 2488 2489#endif /* CONFIG_NO_HZ */ 2490 2491/* 2492 * calc_load - update the avenrun load estimates 10 ticks after the 2493 * CPUs have updated calc_load_tasks. 2494 */ 2495void calc_global_load(unsigned long ticks) 2496{ 2497 long active, delta; 2498 2499 if (time_before(jiffies, calc_load_update + 10)) 2500 return; 2501 2502 /* 2503 * Fold the 'old' idle-delta to include all NO_HZ cpus. 2504 */ 2505 delta = calc_load_fold_idle(); 2506 if (delta) 2507 atomic_long_add(delta, &calc_load_tasks); 2508 2509 active = atomic_long_read(&calc_load_tasks); 2510 active = active > 0 ? active * FIXED_1 : 0; 2511 2512 avenrun[0] = calc_load(avenrun[0], EXP_1, active); 2513 avenrun[1] = calc_load(avenrun[1], EXP_5, active); 2514 avenrun[2] = calc_load(avenrun[2], EXP_15, active); 2515 2516 calc_load_update += LOAD_FREQ; 2517 2518 /* 2519 * In case we idled for multiple LOAD_FREQ intervals, catch up in bulk. 2520 */ 2521 calc_global_nohz(); 2522} 2523 2524/* 2525 * Called from update_cpu_load() to periodically update this CPU's 2526 * active count. 2527 */ 2528static void calc_load_account_active(struct rq *this_rq) 2529{ 2530 long delta; 2531 2532 if (time_before(jiffies, this_rq->calc_load_update)) 2533 return; 2534 2535 delta = calc_load_fold_active(this_rq); 2536 if (delta) 2537 atomic_long_add(delta, &calc_load_tasks); 2538 2539 this_rq->calc_load_update += LOAD_FREQ; 2540} 2541 2542/* 2543 * End of global load-average stuff 2544 */ 2545 2546/* 2547 * The exact cpuload at various idx values, calculated at every tick would be 2548 * load = (2^idx - 1) / 2^idx * load + 1 / 2^idx * cur_load 2549 * 2550 * If a cpu misses updates for n-1 ticks (as it was idle) and update gets called 2551 * on nth tick when cpu may be busy, then we have: 2552 * load = ((2^idx - 1) / 2^idx)^(n-1) * load 2553 * load = (2^idx - 1) / 2^idx) * load + 1 / 2^idx * cur_load 2554 * 2555 * decay_load_missed() below does efficient calculation of 2556 * load = ((2^idx - 1) / 2^idx)^(n-1) * load 2557 * avoiding 0..n-1 loop doing load = ((2^idx - 1) / 2^idx) * load 2558 * 2559 * The calculation is approximated on a 128 point scale. 2560 * degrade_zero_ticks is the number of ticks after which load at any 2561 * particular idx is approximated to be zero. 2562 * degrade_factor is a precomputed table, a row for each load idx. 2563 * Each column corresponds to degradation factor for a power of two ticks, 2564 * based on 128 point scale. 2565 * Example: 2566 * row 2, col 3 (=12) says that the degradation at load idx 2 after 2567 * 8 ticks is 12/128 (which is an approximation of exact factor 3^8/4^8). 2568 * 2569 * With this power of 2 load factors, we can degrade the load n times 2570 * by looking at 1 bits in n and doing as many mult/shift instead of 2571 * n mult/shifts needed by the exact degradation. 2572 */ 2573#define DEGRADE_SHIFT 7 2574static const unsigned char 2575 degrade_zero_ticks[CPU_LOAD_IDX_MAX] = {0, 8, 32, 64, 128}; 2576static const unsigned char 2577 degrade_factor[CPU_LOAD_IDX_MAX][DEGRADE_SHIFT + 1] = { 2578 {0, 0, 0, 0, 0, 0, 0, 0}, 2579 {64, 32, 8, 0, 0, 0, 0, 0}, 2580 {96, 72, 40, 12, 1, 0, 0}, 2581 {112, 98, 75, 43, 15, 1, 0}, 2582 {120, 112, 98, 76, 45, 16, 2} }; 2583 2584/* 2585 * Update cpu_load for any missed ticks, due to tickless idle. The backlog 2586 * would be when CPU is idle and so we just decay the old load without 2587 * adding any new load. 2588 */ 2589static unsigned long 2590decay_load_missed(unsigned long load, unsigned long missed_updates, int idx) 2591{ 2592 int j = 0; 2593 2594 if (!missed_updates) 2595 return load; 2596 2597 if (missed_updates >= degrade_zero_ticks[idx]) 2598 return 0; 2599 2600 if (idx == 1) 2601 return load >> missed_updates; 2602 2603 while (missed_updates) { 2604 if (missed_updates % 2) 2605 load = (load * degrade_factor[idx][j]) >> DEGRADE_SHIFT; 2606 2607 missed_updates >>= 1; 2608 j++; 2609 } 2610 return load; 2611} 2612 2613/* 2614 * Update rq->cpu_load[] statistics. This function is usually called every 2615 * scheduler tick (TICK_NSEC). With tickless idle this will not be called 2616 * every tick. We fix it up based on jiffies. 2617 */ 2618static void __update_cpu_load(struct rq *this_rq, unsigned long this_load, 2619 unsigned long pending_updates) 2620{ 2621 int i, scale; 2622 2623 this_rq->nr_load_updates++; 2624 2625 /* Update our load: */ 2626 this_rq->cpu_load[0] = this_load; /* Fasttrack for idx 0 */ 2627 for (i = 1, scale = 2; i < CPU_LOAD_IDX_MAX; i++, scale += scale) { 2628 unsigned long old_load, new_load; 2629 2630 /* scale is effectively 1 << i now, and >> i divides by scale */ 2631 2632 old_load = this_rq->cpu_load[i]; 2633 old_load = decay_load_missed(old_load, pending_updates - 1, i); 2634 new_load = this_load; 2635 /* 2636 * Round up the averaging division if load is increasing. This 2637 * prevents us from getting stuck on 9 if the load is 10, for 2638 * example. 2639 */ 2640 if (new_load > old_load) 2641 new_load += scale - 1; 2642 2643 this_rq->cpu_load[i] = (old_load * (scale - 1) + new_load) >> i; 2644 } 2645 2646 sched_avg_update(this_rq); 2647} 2648 2649#ifdef CONFIG_NO_HZ 2650/* 2651 * There is no sane way to deal with nohz on smp when using jiffies because the 2652 * cpu doing the jiffies update might drift wrt the cpu doing the jiffy reading 2653 * causing off-by-one errors in observed deltas; {0,2} instead of {1,1}. 2654 * 2655 * Therefore we cannot use the delta approach from the regular tick since that 2656 * would seriously skew the load calculation. However we'll make do for those 2657 * updates happening while idle (nohz_idle_balance) or coming out of idle 2658 * (tick_nohz_idle_exit). 2659 * 2660 * This means we might still be one tick off for nohz periods. 2661 */ 2662 2663/* 2664 * Called from nohz_idle_balance() to update the load ratings before doing the 2665 * idle balance. 2666 */ 2667void update_idle_cpu_load(struct rq *this_rq) 2668{ 2669 unsigned long curr_jiffies = ACCESS_ONCE(jiffies); 2670 unsigned long load = this_rq->load.weight; 2671 unsigned long pending_updates; 2672 2673 /* 2674 * bail if there's load or we're actually up-to-date. 2675 */ 2676 if (load || curr_jiffies == this_rq->last_load_update_tick) 2677 return; 2678 2679 pending_updates = curr_jiffies - this_rq->last_load_update_tick; 2680 this_rq->last_load_update_tick = curr_jiffies; 2681 2682 __update_cpu_load(this_rq, load, pending_updates); 2683} 2684 2685/* 2686 * Called from tick_nohz_idle_exit() -- try and fix up the ticks we missed. 2687 */ 2688void update_cpu_load_nohz(void) 2689{ 2690 struct rq *this_rq = this_rq(); 2691 unsigned long curr_jiffies = ACCESS_ONCE(jiffies); 2692 unsigned long pending_updates; 2693 2694 if (curr_jiffies == this_rq->last_load_update_tick) 2695 return; 2696 2697 raw_spin_lock(&this_rq->lock); 2698 pending_updates = curr_jiffies - this_rq->last_load_update_tick; 2699 if (pending_updates) { 2700 this_rq->last_load_update_tick = curr_jiffies; 2701 /* 2702 * We were idle, this means load 0, the current load might be 2703 * !0 due to remote wakeups and the sort. 2704 */ 2705 __update_cpu_load(this_rq, 0, pending_updates); 2706 } 2707 raw_spin_unlock(&this_rq->lock); 2708} 2709#endif /* CONFIG_NO_HZ */ 2710 2711/* 2712 * Called from scheduler_tick() 2713 */ 2714static void update_cpu_load_active(struct rq *this_rq) 2715{ 2716 /* 2717 * See the mess around update_idle_cpu_load() / update_cpu_load_nohz(). 2718 */ 2719 this_rq->last_load_update_tick = jiffies; 2720 __update_cpu_load(this_rq, this_rq->load.weight, 1); 2721 2722 calc_load_account_active(this_rq); 2723} 2724 2725#ifdef CONFIG_SMP 2726 2727/* 2728 * sched_exec - execve() is a valuable balancing opportunity, because at 2729 * this point the task has the smallest effective memory and cache footprint. 2730 */ 2731void sched_exec(void) 2732{ 2733 struct task_struct *p = current; 2734 unsigned long flags; 2735 int dest_cpu; 2736 2737 raw_spin_lock_irqsave(&p->pi_lock, flags); 2738 dest_cpu = p->sched_class->select_task_rq(p, SD_BALANCE_EXEC, 0); 2739 if (dest_cpu == smp_processor_id()) 2740 goto unlock; 2741 2742 if (likely(cpu_active(dest_cpu))) { 2743 struct migration_arg arg = { p, dest_cpu }; 2744 2745 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 2746 stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg); 2747 return; 2748 } 2749unlock: 2750 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 2751} 2752 2753#endif 2754 2755DEFINE_PER_CPU(struct kernel_stat, kstat); 2756DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat); 2757 2758EXPORT_PER_CPU_SYMBOL(kstat); 2759EXPORT_PER_CPU_SYMBOL(kernel_cpustat); 2760 2761/* 2762 * Return any ns on the sched_clock that have not yet been accounted in 2763 * @p in case that task is currently running. 2764 * 2765 * Called with task_rq_lock() held on @rq. 2766 */ 2767static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq) 2768{ 2769 u64 ns = 0; 2770 2771 if (task_current(rq, p)) { 2772 update_rq_clock(rq); 2773 ns = rq->clock_task - p->se.exec_start; 2774 if ((s64)ns < 0) 2775 ns = 0; 2776 } 2777 2778 return ns; 2779} 2780 2781unsigned long long task_delta_exec(struct task_struct *p) 2782{ 2783 unsigned long flags; 2784 struct rq *rq; 2785 u64 ns = 0; 2786 2787 rq = task_rq_lock(p, &flags); 2788 ns = do_task_delta_exec(p, rq); 2789 task_rq_unlock(rq, p, &flags); 2790 2791 return ns; 2792} 2793 2794/* 2795 * Return accounted runtime for the task. 2796 * In case the task is currently running, return the runtime plus current's 2797 * pending runtime that have not been accounted yet. 2798 */ 2799unsigned long long task_sched_runtime(struct task_struct *p) 2800{ 2801 unsigned long flags; 2802 struct rq *rq; 2803 u64 ns = 0; 2804 2805 rq = task_rq_lock(p, &flags); 2806 ns = p->se.sum_exec_runtime + do_task_delta_exec(p, rq); 2807 task_rq_unlock(rq, p, &flags); 2808 2809 return ns; 2810} 2811 2812#ifdef CONFIG_CGROUP_CPUACCT 2813struct cgroup_subsys cpuacct_subsys; 2814struct cpuacct root_cpuacct; 2815#endif 2816 2817static inline void task_group_account_field(struct task_struct *p, int index, 2818 u64 tmp) 2819{ 2820#ifdef CONFIG_CGROUP_CPUACCT 2821 struct kernel_cpustat *kcpustat; 2822 struct cpuacct *ca; 2823#endif 2824 /* 2825 * Since all updates are sure to touch the root cgroup, we 2826 * get ourselves ahead and touch it first. If the root cgroup 2827 * is the only cgroup, then nothing else should be necessary. 2828 * 2829 */ 2830 __get_cpu_var(kernel_cpustat).cpustat[index] += tmp; 2831 2832#ifdef CONFIG_CGROUP_CPUACCT 2833 if (unlikely(!cpuacct_subsys.active)) 2834 return; 2835 2836 rcu_read_lock(); 2837 ca = task_ca(p); 2838 while (ca && (ca != &root_cpuacct)) { 2839 kcpustat = this_cpu_ptr(ca->cpustat); 2840 kcpustat->cpustat[index] += tmp; 2841 ca = parent_ca(ca); 2842 } 2843 rcu_read_unlock(); 2844#endif 2845} 2846 2847 2848/* 2849 * Account user cpu time to a process. 2850 * @p: the process that the cpu time gets accounted to 2851 * @cputime: the cpu time spent in user space since the last update 2852 * @cputime_scaled: cputime scaled by cpu frequency 2853 */ 2854void account_user_time(struct task_struct *p, cputime_t cputime, 2855 cputime_t cputime_scaled) 2856{ 2857 int index; 2858 2859 /* Add user time to process. */ 2860 p->utime += cputime; 2861 p->utimescaled += cputime_scaled; 2862 account_group_user_time(p, cputime); 2863 2864 index = (TASK_NICE(p) > 0) ? CPUTIME_NICE : CPUTIME_USER; 2865 2866 /* Add user time to cpustat. */ 2867 task_group_account_field(p, index, (__force u64) cputime); 2868 2869 /* Account for user time used */ 2870 acct_update_integrals(p); 2871} 2872 2873/* 2874 * Account guest cpu time to a process. 2875 * @p: the process that the cpu time gets accounted to 2876 * @cputime: the cpu time spent in virtual machine since the last update 2877 * @cputime_scaled: cputime scaled by cpu frequency 2878 */ 2879static void account_guest_time(struct task_struct *p, cputime_t cputime, 2880 cputime_t cputime_scaled) 2881{ 2882 u64 *cpustat = kcpustat_this_cpu->cpustat; 2883 2884 /* Add guest time to process. */ 2885 p->utime += cputime; 2886 p->utimescaled += cputime_scaled; 2887 account_group_user_time(p, cputime); 2888 p->gtime += cputime; 2889 2890 /* Add guest time to cpustat. */ 2891 if (TASK_NICE(p) > 0) { 2892 cpustat[CPUTIME_NICE] += (__force u64) cputime; 2893 cpustat[CPUTIME_GUEST_NICE] += (__force u64) cputime; 2894 } else { 2895 cpustat[CPUTIME_USER] += (__force u64) cputime; 2896 cpustat[CPUTIME_GUEST] += (__force u64) cputime; 2897 } 2898} 2899 2900/* 2901 * Account system cpu time to a process and desired cpustat field 2902 * @p: the process that the cpu time gets accounted to 2903 * @cputime: the cpu time spent in kernel space since the last update 2904 * @cputime_scaled: cputime scaled by cpu frequency 2905 * @target_cputime64: pointer to cpustat field that has to be updated 2906 */ 2907static inline 2908void __account_system_time(struct task_struct *p, cputime_t cputime, 2909 cputime_t cputime_scaled, int index) 2910{ 2911 /* Add system time to process. */ 2912 p->stime += cputime; 2913 p->stimescaled += cputime_scaled; 2914 account_group_system_time(p, cputime); 2915 2916 /* Add system time to cpustat. */ 2917 task_group_account_field(p, index, (__force u64) cputime); 2918 2919 /* Account for system time used */ 2920 acct_update_integrals(p); 2921} 2922 2923/* 2924 * Account system cpu time to a process. 2925 * @p: the process that the cpu time gets accounted to 2926 * @hardirq_offset: the offset to subtract from hardirq_count() 2927 * @cputime: the cpu time spent in kernel space since the last update 2928 * @cputime_scaled: cputime scaled by cpu frequency 2929 */ 2930void account_system_time(struct task_struct *p, int hardirq_offset, 2931 cputime_t cputime, cputime_t cputime_scaled) 2932{ 2933 int index; 2934 2935 if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) { 2936 account_guest_time(p, cputime, cputime_scaled); 2937 return; 2938 } 2939 2940 if (hardirq_count() - hardirq_offset) 2941 index = CPUTIME_IRQ; 2942 else if (in_serving_softirq()) 2943 index = CPUTIME_SOFTIRQ; 2944 else 2945 index = CPUTIME_SYSTEM; 2946 2947 __account_system_time(p, cputime, cputime_scaled, index); 2948} 2949 2950/* 2951 * Account for involuntary wait time. 2952 * @cputime: the cpu time spent in involuntary wait 2953 */ 2954void account_steal_time(cputime_t cputime) 2955{ 2956 u64 *cpustat = kcpustat_this_cpu->cpustat; 2957 2958 cpustat[CPUTIME_STEAL] += (__force u64) cputime; 2959} 2960 2961/* 2962 * Account for idle time. 2963 * @cputime: the cpu time spent in idle wait 2964 */ 2965void account_idle_time(cputime_t cputime) 2966{ 2967 u64 *cpustat = kcpustat_this_cpu->cpustat; 2968 struct rq *rq = this_rq(); 2969 2970 if (atomic_read(&rq->nr_iowait) > 0) 2971 cpustat[CPUTIME_IOWAIT] += (__force u64) cputime; 2972 else 2973 cpustat[CPUTIME_IDLE] += (__force u64) cputime; 2974} 2975 2976static __always_inline bool steal_account_process_tick(void) 2977{ 2978#ifdef CONFIG_PARAVIRT 2979 if (static_key_false(¶virt_steal_enabled)) { 2980 u64 steal, st = 0; 2981 2982 steal = paravirt_steal_clock(smp_processor_id()); 2983 steal -= this_rq()->prev_steal_time; 2984 2985 st = steal_ticks(steal); 2986 this_rq()->prev_steal_time += st * TICK_NSEC; 2987 2988 account_steal_time(st); 2989 return st; 2990 } 2991#endif 2992 return false; 2993} 2994 2995#ifndef CONFIG_VIRT_CPU_ACCOUNTING 2996 2997#ifdef CONFIG_IRQ_TIME_ACCOUNTING 2998/* 2999 * Account a tick to a process and cpustat 3000 * @p: the process that the cpu time gets accounted to 3001 * @user_tick: is the tick from userspace 3002 * @rq: the pointer to rq 3003 * 3004 * Tick demultiplexing follows the order 3005 * - pending hardirq update 3006 * - pending softirq update 3007 * - user_time 3008 * - idle_time 3009 * - system time 3010 * - check for guest_time 3011 * - else account as system_time 3012 * 3013 * Check for hardirq is done both for system and user time as there is 3014 * no timer going off while we are on hardirq and hence we may never get an 3015 * opportunity to update it solely in system time. 3016 * p->stime and friends are only updated on system time and not on irq 3017 * softirq as those do not count in task exec_runtime any more. 3018 */ 3019static void irqtime_account_process_tick(struct task_struct *p, int user_tick, 3020 struct rq *rq) 3021{ 3022 cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy); 3023 u64 *cpustat = kcpustat_this_cpu->cpustat; 3024 3025 if (steal_account_process_tick()) 3026 return; 3027 3028 if (irqtime_account_hi_update()) { 3029 cpustat[CPUTIME_IRQ] += (__force u64) cputime_one_jiffy; 3030 } else if (irqtime_account_si_update()) { 3031 cpustat[CPUTIME_SOFTIRQ] += (__force u64) cputime_one_jiffy; 3032 } else if (this_cpu_ksoftirqd() == p) { 3033 /* 3034 * ksoftirqd time do not get accounted in cpu_softirq_time. 3035 * So, we have to handle it separately here. 3036 * Also, p->stime needs to be updated for ksoftirqd. 3037 */ 3038 __account_system_time(p, cputime_one_jiffy, one_jiffy_scaled, 3039 CPUTIME_SOFTIRQ); 3040 } else if (user_tick) { 3041 account_user_time(p, cputime_one_jiffy, one_jiffy_scaled); 3042 } else if (p == rq->idle) { 3043 account_idle_time(cputime_one_jiffy); 3044 } else if (p->flags & PF_VCPU) { /* System time or guest time */ 3045 account_guest_time(p, cputime_one_jiffy, one_jiffy_scaled); 3046 } else { 3047 __account_system_time(p, cputime_one_jiffy, one_jiffy_scaled, 3048 CPUTIME_SYSTEM); 3049 } 3050} 3051 3052static void irqtime_account_idle_ticks(int ticks) 3053{ 3054 int i; 3055 struct rq *rq = this_rq(); 3056 3057 for (i = 0; i < ticks; i++) 3058 irqtime_account_process_tick(current, 0, rq); 3059} 3060#else /* CONFIG_IRQ_TIME_ACCOUNTING */ 3061static void irqtime_account_idle_ticks(int ticks) {} 3062static void irqtime_account_process_tick(struct task_struct *p, int user_tick, 3063 struct rq *rq) {} 3064#endif /* CONFIG_IRQ_TIME_ACCOUNTING */ 3065 3066/* 3067 * Account a single tick of cpu time. 3068 * @p: the process that the cpu time gets accounted to 3069 * @user_tick: indicates if the tick is a user or a system tick 3070 */ 3071void account_process_tick(struct task_struct *p, int user_tick) 3072{ 3073 cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy); 3074 struct rq *rq = this_rq(); 3075 3076 if (sched_clock_irqtime) { 3077 irqtime_account_process_tick(p, user_tick, rq); 3078 return; 3079 } 3080 3081 if (steal_account_process_tick()) 3082 return; 3083 3084 if (user_tick) 3085 account_user_time(p, cputime_one_jiffy, one_jiffy_scaled); 3086 else if ((p != rq->idle) || (irq_count() != HARDIRQ_OFFSET)) 3087 account_system_time(p, HARDIRQ_OFFSET, cputime_one_jiffy, 3088 one_jiffy_scaled); 3089 else 3090 account_idle_time(cputime_one_jiffy); 3091} 3092 3093/* 3094 * Account multiple ticks of steal time. 3095 * @p: the process from which the cpu time has been stolen 3096 * @ticks: number of stolen ticks 3097 */ 3098void account_steal_ticks(unsigned long ticks) 3099{ 3100 account_steal_time(jiffies_to_cputime(ticks)); 3101} 3102 3103/* 3104 * Account multiple ticks of idle time. 3105 * @ticks: number of stolen ticks 3106 */ 3107void account_idle_ticks(unsigned long ticks) 3108{ 3109 3110 if (sched_clock_irqtime) { 3111 irqtime_account_idle_ticks(ticks); 3112 return; 3113 } 3114 3115 account_idle_time(jiffies_to_cputime(ticks)); 3116} 3117 3118#endif 3119 3120/* 3121 * Use precise platform statistics if available: 3122 */ 3123#ifdef CONFIG_VIRT_CPU_ACCOUNTING 3124void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st) 3125{ 3126 *ut = p->utime; 3127 *st = p->stime; 3128} 3129 3130void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st) 3131{ 3132 struct task_cputime cputime; 3133 3134 thread_group_cputime(p, &cputime); 3135 3136 *ut = cputime.utime; 3137 *st = cputime.stime; 3138} 3139#else 3140 3141#ifndef nsecs_to_cputime 3142# define nsecs_to_cputime(__nsecs) nsecs_to_jiffies(__nsecs) 3143#endif 3144 3145void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st) 3146{ 3147 cputime_t rtime, utime = p->utime, total = utime + p->stime; 3148 3149 /* 3150 * Use CFS's precise accounting: 3151 */ 3152 rtime = nsecs_to_cputime(p->se.sum_exec_runtime); 3153 3154 if (total) { 3155 u64 temp = (__force u64) rtime; 3156 3157 temp *= (__force u64) utime; 3158 do_div(temp, (__force u32) total); 3159 utime = (__force cputime_t) temp; 3160 } else 3161 utime = rtime; 3162 3163 /* 3164 * Compare with previous values, to keep monotonicity: 3165 */ 3166 p->prev_utime = max(p->prev_utime, utime); 3167 p->prev_stime = max(p->prev_stime, rtime - p->prev_utime); 3168 3169 *ut = p->prev_utime; 3170 *st = p->prev_stime; 3171} 3172 3173/* 3174 * Must be called with siglock held. 3175 */ 3176void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st) 3177{ 3178 struct signal_struct *sig = p->signal; 3179 struct task_cputime cputime; 3180 cputime_t rtime, utime, total; 3181 3182 thread_group_cputime(p, &cputime); 3183 3184 total = cputime.utime + cputime.stime; 3185 rtime = nsecs_to_cputime(cputime.sum_exec_runtime); 3186 3187 if (total) { 3188 u64 temp = (__force u64) rtime; 3189 3190 temp *= (__force u64) cputime.utime; 3191 do_div(temp, (__force u32) total); 3192 utime = (__force cputime_t) temp; 3193 } else 3194 utime = rtime; 3195 3196 sig->prev_utime = max(sig->prev_utime, utime); 3197 sig->prev_stime = max(sig->prev_stime, rtime - sig->prev_utime); 3198 3199 *ut = sig->prev_utime; 3200 *st = sig->prev_stime; 3201} 3202#endif 3203 3204/* 3205 * This function gets called by the timer code, with HZ frequency. 3206 * We call it with interrupts disabled. 3207 */ 3208void scheduler_tick(void) 3209{ 3210 int cpu = smp_processor_id(); 3211 struct rq *rq = cpu_rq(cpu); 3212 struct task_struct *curr = rq->curr; 3213 3214 sched_clock_tick(); 3215 3216 raw_spin_lock(&rq->lock); 3217 update_rq_clock(rq); 3218 update_cpu_load_active(rq); 3219 curr->sched_class->task_tick(rq, curr, 0); 3220 raw_spin_unlock(&rq->lock); 3221 3222 perf_event_task_tick(); 3223 3224#ifdef CONFIG_SMP 3225 rq->idle_balance = idle_cpu(cpu); 3226 trigger_load_balance(rq, cpu); 3227#endif 3228} 3229 3230notrace unsigned long get_parent_ip(unsigned long addr) 3231{ 3232 if (in_lock_functions(addr)) { 3233 addr = CALLER_ADDR2; 3234 if (in_lock_functions(addr)) 3235 addr = CALLER_ADDR3; 3236 } 3237 return addr; 3238} 3239 3240#if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \ 3241 defined(CONFIG_PREEMPT_TRACER)) 3242 3243void __kprobes add_preempt_count(int val) 3244{ 3245#ifdef CONFIG_DEBUG_PREEMPT 3246 /* 3247 * Underflow? 3248 */ 3249 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) 3250 return; 3251#endif 3252 preempt_count() += val; 3253#ifdef CONFIG_DEBUG_PREEMPT 3254 /* 3255 * Spinlock count overflowing soon? 3256 */ 3257 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= 3258 PREEMPT_MASK - 10); 3259#endif 3260 if (preempt_count() == val) 3261 trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); 3262} 3263EXPORT_SYMBOL(add_preempt_count); 3264 3265void __kprobes sub_preempt_count(int val) 3266{ 3267#ifdef CONFIG_DEBUG_PREEMPT 3268 /* 3269 * Underflow? 3270 */ 3271 if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) 3272 return; 3273 /* 3274 * Is the spinlock portion underflowing? 3275 */ 3276 if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && 3277 !(preempt_count() & PREEMPT_MASK))) 3278 return; 3279#endif 3280 3281 if (preempt_count() == val) 3282 trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); 3283 preempt_count() -= val; 3284} 3285EXPORT_SYMBOL(sub_preempt_count); 3286 3287#endif 3288 3289/* 3290 * Print scheduling while atomic bug: 3291 */ 3292static noinline void __schedule_bug(struct task_struct *prev) 3293{ 3294 if (oops_in_progress) 3295 return; 3296 3297 printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n", 3298 prev->comm, prev->pid, preempt_count()); 3299 3300 debug_show_held_locks(prev); 3301 print_modules(); 3302 if (irqs_disabled()) 3303 print_irqtrace_events(prev); 3304 dump_stack(); 3305 add_taint(TAINT_WARN); 3306} 3307 3308/* 3309 * Various schedule()-time debugging checks and statistics: 3310 */ 3311static inline void schedule_debug(struct task_struct *prev) 3312{ 3313 /* 3314 * Test if we are atomic. Since do_exit() needs to call into 3315 * schedule() atomically, we ignore that path for now. 3316 * Otherwise, whine if we are scheduling when we should not be. 3317 */ 3318 if (unlikely(in_atomic_preempt_off() && !prev->exit_state)) 3319 __schedule_bug(prev); 3320 rcu_sleep_check(); 3321 3322 profile_hit(SCHED_PROFILING, __builtin_return_address(0)); 3323 3324 schedstat_inc(this_rq(), sched_count); 3325} 3326 3327static void put_prev_task(struct rq *rq, struct task_struct *prev) 3328{ 3329 if (prev->on_rq || rq->skip_clock_update < 0) 3330 update_rq_clock(rq); 3331 prev->sched_class->put_prev_task(rq, prev); 3332} 3333 3334/* 3335 * Pick up the highest-prio task: 3336 */ 3337static inline struct task_struct * 3338pick_next_task(struct rq *rq) 3339{ 3340 const struct sched_class *class; 3341 struct task_struct *p; 3342 3343 /* 3344 * Optimization: we know that if all tasks are in 3345 * the fair class we can call that function directly: 3346 */ 3347 if (likely(rq->nr_running == rq->cfs.h_nr_running)) { 3348 p = fair_sched_class.pick_next_task(rq); 3349 if (likely(p)) 3350 return p; 3351 } 3352 3353 for_each_class(class) { 3354 p = class->pick_next_task(rq); 3355 if (p) 3356 return p; 3357 } 3358 3359 BUG(); /* the idle class will always have a runnable task */ 3360} 3361 3362/* 3363 * __schedule() is the main scheduler function. 3364 */ 3365static void __sched __schedule(void) 3366{ 3367 struct task_struct *prev, *next; 3368 unsigned long *switch_count; 3369 struct rq *rq; 3370 int cpu; 3371 3372need_resched: 3373 preempt_disable(); 3374 cpu = smp_processor_id(); 3375 rq = cpu_rq(cpu); 3376 rcu_note_context_switch(cpu); 3377 prev = rq->curr; 3378 3379 schedule_debug(prev); 3380 3381 if (sched_feat(HRTICK)) 3382 hrtick_clear(rq); 3383 3384 raw_spin_lock_irq(&rq->lock); 3385 3386 switch_count = &prev->nivcsw; 3387 if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { 3388 if (unlikely(signal_pending_state(prev->state, prev))) { 3389 prev->state = TASK_RUNNING; 3390 } else { 3391 deactivate_task(rq, prev, DEQUEUE_SLEEP); 3392 prev->on_rq = 0; 3393 3394 /* 3395 * If a worker went to sleep, notify and ask workqueue 3396 * whether it wants to wake up a task to maintain 3397 * concurrency. 3398 */ 3399 if (prev->flags & PF_WQ_WORKER) { 3400 struct task_struct *to_wakeup; 3401 3402 to_wakeup = wq_worker_sleeping(prev, cpu); 3403 if (to_wakeup) 3404 try_to_wake_up_local(to_wakeup); 3405 } 3406 } 3407 switch_count = &prev->nvcsw; 3408 } 3409 3410 pre_schedule(rq, prev); 3411 3412 if (unlikely(!rq->nr_running)) 3413 idle_balance(cpu, rq); 3414 3415 put_prev_task(rq, prev); 3416 next = pick_next_task(rq); 3417 clear_tsk_need_resched(prev); 3418 rq->skip_clock_update = 0; 3419 3420 if (likely(prev != next)) { 3421 rq->nr_switches++; 3422 rq->curr = next; 3423 ++*switch_count; 3424 3425 context_switch(rq, prev, next); /* unlocks the rq */ 3426 /* 3427 * The context switch have flipped the stack from under us 3428 * and restored the local variables which were saved when 3429 * this task called schedule() in the past. prev == current 3430 * is still correct, but it can be moved to another cpu/rq. 3431 */ 3432 cpu = smp_processor_id(); 3433 rq = cpu_rq(cpu); 3434 } else 3435 raw_spin_unlock_irq(&rq->lock); 3436 3437 post_schedule(rq); 3438 3439 sched_preempt_enable_no_resched(); 3440 if (need_resched()) 3441 goto need_resched; 3442} 3443 3444static inline void sched_submit_work(struct task_struct *tsk) 3445{ 3446 if (!tsk->state || tsk_is_pi_blocked(tsk)) 3447 return; 3448 /* 3449 * If we are going to sleep and we have plugged IO queued, 3450 * make sure to submit it to avoid deadlocks. 3451 */ 3452 if (blk_needs_flush_plug(tsk)) 3453 blk_schedule_flush_plug(tsk); 3454} 3455 3456asmlinkage void __sched schedule(void) 3457{ 3458 struct task_struct *tsk = current; 3459 3460 sched_submit_work(tsk); 3461 __schedule(); 3462} 3463EXPORT_SYMBOL(schedule); 3464 3465/** 3466 * schedule_preempt_disabled - called with preemption disabled 3467 * 3468 * Returns with preemption disabled. Note: preempt_count must be 1 3469 */ 3470void __sched schedule_preempt_disabled(void) 3471{ 3472 sched_preempt_enable_no_resched(); 3473 schedule(); 3474 preempt_disable(); 3475} 3476 3477#ifdef CONFIG_MUTEX_SPIN_ON_OWNER 3478 3479static inline bool owner_running(struct mutex *lock, struct task_struct *owner) 3480{ 3481 if (lock->owner != owner) 3482 return false; 3483 3484 /* 3485 * Ensure we emit the owner->on_cpu, dereference _after_ checking 3486 * lock->owner still matches owner, if that fails, owner might 3487 * point to free()d memory, if it still matches, the rcu_read_lock() 3488 * ensures the memory stays valid. 3489 */ 3490 barrier(); 3491 3492 return owner->on_cpu; 3493} 3494 3495/* 3496 * Look out! "owner" is an entirely speculative pointer 3497 * access and not reliable. 3498 */ 3499int mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner) 3500{ 3501 if (!sched_feat(OWNER_SPIN)) 3502 return 0; 3503 3504 rcu_read_lock(); 3505 while (owner_running(lock, owner)) { 3506 if (need_resched()) 3507 break; 3508 3509 arch_mutex_cpu_relax(); 3510 } 3511 rcu_read_unlock(); 3512 3513 /* 3514 * We break out the loop above on need_resched() and when the 3515 * owner changed, which is a sign for heavy contention. Return 3516 * success only when lock->owner is NULL. 3517 */ 3518 return lock->owner == NULL; 3519} 3520#endif 3521 3522#ifdef CONFIG_PREEMPT 3523/* 3524 * this is the entry point to schedule() from in-kernel preemption 3525 * off of preempt_enable. Kernel preemptions off return from interrupt 3526 * occur there and call schedule directly. 3527 */ 3528asmlinkage void __sched notrace preempt_schedule(void) 3529{ 3530 struct thread_info *ti = current_thread_info(); 3531 3532 /* 3533 * If there is a non-zero preempt_count or interrupts are disabled, 3534 * we do not want to preempt the current task. Just return.. 3535 */ 3536 if (likely(ti->preempt_count || irqs_disabled())) 3537 return; 3538 3539 do { 3540 add_preempt_count_notrace(PREEMPT_ACTIVE); 3541 __schedule(); 3542 sub_preempt_count_notrace(PREEMPT_ACTIVE); 3543 3544 /* 3545 * Check again in case we missed a preemption opportunity 3546 * between schedule and now. 3547 */ 3548 barrier(); 3549 } while (need_resched()); 3550} 3551EXPORT_SYMBOL(preempt_schedule); 3552 3553/* 3554 * this is the entry point to schedule() from kernel preemption 3555 * off of irq context. 3556 * Note, that this is called and return with irqs disabled. This will 3557 * protect us against recursive calling from irq. 3558 */ 3559asmlinkage void __sched preempt_schedule_irq(void) 3560{ 3561 struct thread_info *ti = current_thread_info(); 3562 3563 /* Catch callers which need to be fixed */ 3564 BUG_ON(ti->preempt_count || !irqs_disabled()); 3565 3566 do { 3567 add_preempt_count(PREEMPT_ACTIVE); 3568 local_irq_enable(); 3569 __schedule(); 3570 local_irq_disable(); 3571 sub_preempt_count(PREEMPT_ACTIVE); 3572 3573 /* 3574 * Check again in case we missed a preemption opportunity 3575 * between schedule and now. 3576 */ 3577 barrier(); 3578 } while (need_resched()); 3579} 3580 3581#endif /* CONFIG_PREEMPT */ 3582 3583int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags, 3584 void *key) 3585{ 3586 return try_to_wake_up(curr->private, mode, wake_flags); 3587} 3588EXPORT_SYMBOL(default_wake_function); 3589 3590/* 3591 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just 3592 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve 3593 * number) then we wake all the non-exclusive tasks and one exclusive task. 3594 * 3595 * There are circumstances in which we can try to wake a task which has already 3596 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns 3597 * zero in this (rare) case, and we handle it by continuing to scan the queue. 3598 */ 3599static void __wake_up_common(wait_queue_head_t *q, unsigned int mode, 3600 int nr_exclusive, int wake_flags, void *key) 3601{ 3602 wait_queue_t *curr, *next; 3603 3604 list_for_each_entry_safe(curr, next, &q->task_list, task_list) { 3605 unsigned flags = curr->flags; 3606 3607 if (curr->func(curr, mode, wake_flags, key) && 3608 (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive) 3609 break; 3610 } 3611} 3612 3613/** 3614 * __wake_up - wake up threads blocked on a waitqueue. 3615 * @q: the waitqueue 3616 * @mode: which threads 3617 * @nr_exclusive: how many wake-one or wake-many threads to wake up 3618 * @key: is directly passed to the wakeup function 3619 * 3620 * It may be assumed that this function implies a write memory barrier before 3621 * changing the task state if and only if any tasks are woken up. 3622 */ 3623void __wake_up(wait_queue_head_t *q, unsigned int mode, 3624 int nr_exclusive, void *key) 3625{ 3626 unsigned long flags; 3627 3628 spin_lock_irqsave(&q->lock, flags); 3629 __wake_up_common(q, mode, nr_exclusive, 0, key); 3630 spin_unlock_irqrestore(&q->lock, flags); 3631} 3632EXPORT_SYMBOL(__wake_up); 3633 3634/* 3635 * Same as __wake_up but called with the spinlock in wait_queue_head_t held. 3636 */ 3637void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr) 3638{ 3639 __wake_up_common(q, mode, nr, 0, NULL); 3640} 3641EXPORT_SYMBOL_GPL(__wake_up_locked); 3642 3643void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key) 3644{ 3645 __wake_up_common(q, mode, 1, 0, key); 3646} 3647EXPORT_SYMBOL_GPL(__wake_up_locked_key); 3648 3649/** 3650 * __wake_up_sync_key - wake up threads blocked on a waitqueue. 3651 * @q: the waitqueue 3652 * @mode: which threads 3653 * @nr_exclusive: how many wake-one or wake-many threads to wake up 3654 * @key: opaque value to be passed to wakeup targets 3655 * 3656 * The sync wakeup differs that the waker knows that it will schedule 3657 * away soon, so while the target thread will be woken up, it will not 3658 * be migrated to another CPU - ie. the two threads are 'synchronized' 3659 * with each other. This can prevent needless bouncing between CPUs. 3660 * 3661 * On UP it can prevent extra preemption. 3662 * 3663 * It may be assumed that this function implies a write memory barrier before 3664 * changing the task state if and only if any tasks are woken up. 3665 */ 3666void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, 3667 int nr_exclusive, void *key) 3668{ 3669 unsigned long flags; 3670 int wake_flags = WF_SYNC; 3671 3672 if (unlikely(!q)) 3673 return; 3674 3675 if (unlikely(!nr_exclusive)) 3676 wake_flags = 0; 3677 3678 spin_lock_irqsave(&q->lock, flags); 3679 __wake_up_common(q, mode, nr_exclusive, wake_flags, key); 3680 spin_unlock_irqrestore(&q->lock, flags); 3681} 3682EXPORT_SYMBOL_GPL(__wake_up_sync_key); 3683 3684/* 3685 * __wake_up_sync - see __wake_up_sync_key() 3686 */ 3687void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive) 3688{ 3689 __wake_up_sync_key(q, mode, nr_exclusive, NULL); 3690} 3691EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */ 3692 3693/** 3694 * complete: - signals a single thread waiting on this completion 3695 * @x: holds the state of this particular completion 3696 * 3697 * This will wake up a single thread waiting on this completion. Threads will be 3698 * awakened in the same order in which they were queued. 3699 * 3700 * See also complete_all(), wait_for_completion() and related routines. 3701 * 3702 * It may be assumed that this function implies a write memory barrier before 3703 * changing the task state if and only if any tasks are woken up. 3704 */ 3705void complete(struct completion *x) 3706{ 3707 unsigned long flags; 3708 3709 spin_lock_irqsave(&x->wait.lock, flags); 3710 x->done++; 3711 __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL); 3712 spin_unlock_irqrestore(&x->wait.lock, flags); 3713} 3714EXPORT_SYMBOL(complete); 3715 3716/** 3717 * complete_all: - signals all threads waiting on this completion 3718 * @x: holds the state of this particular completion 3719 * 3720 * This will wake up all threads waiting on this particular completion event. 3721 * 3722 * It may be assumed that this function implies a write memory barrier before 3723 * changing the task state if and only if any tasks are woken up. 3724 */ 3725void complete_all(struct completion *x) 3726{ 3727 unsigned long flags; 3728 3729 spin_lock_irqsave(&x->wait.lock, flags); 3730 x->done += UINT_MAX/2; 3731 __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL); 3732 spin_unlock_irqrestore(&x->wait.lock, flags); 3733} 3734EXPORT_SYMBOL(complete_all); 3735 3736static inline long __sched 3737do_wait_for_common(struct completion *x, long timeout, int state) 3738{ 3739 if (!x->done) { 3740 DECLARE_WAITQUEUE(wait, current); 3741 3742 __add_wait_queue_tail_exclusive(&x->wait, &wait); 3743 do { 3744 if (signal_pending_state(state, current)) { 3745 timeout = -ERESTARTSYS; 3746 break; 3747 } 3748 __set_current_state(state); 3749 spin_unlock_irq(&x->wait.lock); 3750 timeout = schedule_timeout(timeout); 3751 spin_lock_irq(&x->wait.lock); 3752 } while (!x->done && timeout); 3753 __remove_wait_queue(&x->wait, &wait); 3754 if (!x->done) 3755 return timeout; 3756 } 3757 x->done--; 3758 return timeout ?: 1; 3759} 3760 3761static long __sched 3762wait_for_common(struct completion *x, long timeout, int state) 3763{ 3764 might_sleep(); 3765 3766 spin_lock_irq(&x->wait.lock); 3767 timeout = do_wait_for_common(x, timeout, state); 3768 spin_unlock_irq(&x->wait.lock); 3769 return timeout; 3770} 3771 3772/** 3773 * wait_for_completion: - waits for completion of a task 3774 * @x: holds the state of this particular completion 3775 * 3776 * This waits to be signaled for completion of a specific task. It is NOT 3777 * interruptible and there is no timeout. 3778 * 3779 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout 3780 * and interrupt capability. Also see complete(). 3781 */ 3782void __sched wait_for_completion(struct completion *x) 3783{ 3784 wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE); 3785} 3786EXPORT_SYMBOL(wait_for_completion); 3787 3788/** 3789 * wait_for_completion_timeout: - waits for completion of a task (w/timeout) 3790 * @x: holds the state of this particular completion 3791 * @timeout: timeout value in jiffies 3792 * 3793 * This waits for either a completion of a specific task to be signaled or for a 3794 * specified timeout to expire. The timeout is in jiffies. It is not 3795 * interruptible. 3796 * 3797 * The return value is 0 if timed out, and positive (at least 1, or number of 3798 * jiffies left till timeout) if completed. 3799 */ 3800unsigned long __sched 3801wait_for_completion_timeout(struct completion *x, unsigned long timeout) 3802{ 3803 return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE); 3804} 3805EXPORT_SYMBOL(wait_for_completion_timeout); 3806 3807/** 3808 * wait_for_completion_interruptible: - waits for completion of a task (w/intr) 3809 * @x: holds the state of this particular completion 3810 * 3811 * This waits for completion of a specific task to be signaled. It is 3812 * interruptible. 3813 * 3814 * The return value is -ERESTARTSYS if interrupted, 0 if completed. 3815 */ 3816int __sched wait_for_completion_interruptible(struct completion *x) 3817{ 3818 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE); 3819 if (t == -ERESTARTSYS) 3820 return t; 3821 return 0; 3822} 3823EXPORT_SYMBOL(wait_for_completion_interruptible); 3824 3825/** 3826 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr)) 3827 * @x: holds the state of this particular completion 3828 * @timeout: timeout value in jiffies 3829 * 3830 * This waits for either a completion of a specific task to be signaled or for a 3831 * specified timeout to expire. It is interruptible. The timeout is in jiffies. 3832 * 3833 * The return value is -ERESTARTSYS if interrupted, 0 if timed out, 3834 * positive (at least 1, or number of jiffies left till timeout) if completed. 3835 */ 3836long __sched 3837wait_for_completion_interruptible_timeout(struct completion *x, 3838 unsigned long timeout) 3839{ 3840 return wait_for_common(x, timeout, TASK_INTERRUPTIBLE); 3841} 3842EXPORT_SYMBOL(wait_for_completion_interruptible_timeout); 3843 3844/** 3845 * wait_for_completion_killable: - waits for completion of a task (killable) 3846 * @x: holds the state of this particular completion 3847 * 3848 * This waits to be signaled for completion of a specific task. It can be 3849 * interrupted by a kill signal. 3850 * 3851 * The return value is -ERESTARTSYS if interrupted, 0 if completed. 3852 */ 3853int __sched wait_for_completion_killable(struct completion *x) 3854{ 3855 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE); 3856 if (t == -ERESTARTSYS) 3857 return t; 3858 return 0; 3859} 3860EXPORT_SYMBOL(wait_for_completion_killable); 3861 3862/** 3863 * wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable)) 3864 * @x: holds the state of this particular completion 3865 * @timeout: timeout value in jiffies 3866 * 3867 * This waits for either a completion of a specific task to be 3868 * signaled or for a specified timeout to expire. It can be 3869 * interrupted by a kill signal. The timeout is in jiffies. 3870 * 3871 * The return value is -ERESTARTSYS if interrupted, 0 if timed out, 3872 * positive (at least 1, or number of jiffies left till timeout) if completed. 3873 */ 3874long __sched 3875wait_for_completion_killable_timeout(struct completion *x, 3876 unsigned long timeout) 3877{ 3878 return wait_for_common(x, timeout, TASK_KILLABLE); 3879} 3880EXPORT_SYMBOL(wait_for_completion_killable_timeout); 3881 3882/** 3883 * try_wait_for_completion - try to decrement a completion without blocking 3884 * @x: completion structure 3885 * 3886 * Returns: 0 if a decrement cannot be done without blocking 3887 * 1 if a decrement succeeded. 3888 * 3889 * If a completion is being used as a counting completion, 3890 * attempt to decrement the counter without blocking. This 3891 * enables us to avoid waiting if the resource the completion 3892 * is protecting is not available. 3893 */ 3894bool try_wait_for_completion(struct completion *x) 3895{ 3896 unsigned long flags; 3897 int ret = 1; 3898 3899 spin_lock_irqsave(&x->wait.lock, flags); 3900 if (!x->done) 3901 ret = 0; 3902 else 3903 x->done--; 3904 spin_unlock_irqrestore(&x->wait.lock, flags); 3905 return ret; 3906} 3907EXPORT_SYMBOL(try_wait_for_completion); 3908 3909/** 3910 * completion_done - Test to see if a completion has any waiters 3911 * @x: completion structure 3912 * 3913 * Returns: 0 if there are waiters (wait_for_completion() in progress) 3914 * 1 if there are no waiters. 3915 * 3916 */ 3917bool completion_done(struct completion *x) 3918{ 3919 unsigned long flags; 3920 int ret = 1; 3921 3922 spin_lock_irqsave(&x->wait.lock, flags); 3923 if (!x->done) 3924 ret = 0; 3925 spin_unlock_irqrestore(&x->wait.lock, flags); 3926 return ret; 3927} 3928EXPORT_SYMBOL(completion_done); 3929 3930static long __sched 3931sleep_on_common(wait_queue_head_t *q, int state, long timeout) 3932{ 3933 unsigned long flags; 3934 wait_queue_t wait; 3935 3936 init_waitqueue_entry(&wait, current); 3937 3938 __set_current_state(state); 3939 3940 spin_lock_irqsave(&q->lock, flags); 3941 __add_wait_queue(q, &wait); 3942 spin_unlock(&q->lock); 3943 timeout = schedule_timeout(timeout); 3944 spin_lock_irq(&q->lock); 3945 __remove_wait_queue(q, &wait); 3946 spin_unlock_irqrestore(&q->lock, flags); 3947 3948 return timeout; 3949} 3950 3951void __sched interruptible_sleep_on(wait_queue_head_t *q) 3952{ 3953 sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); 3954} 3955EXPORT_SYMBOL(interruptible_sleep_on); 3956 3957long __sched 3958interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout) 3959{ 3960 return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout); 3961} 3962EXPORT_SYMBOL(interruptible_sleep_on_timeout); 3963 3964void __sched sleep_on(wait_queue_head_t *q) 3965{ 3966 sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); 3967} 3968EXPORT_SYMBOL(sleep_on); 3969 3970long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout) 3971{ 3972 return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout); 3973} 3974EXPORT_SYMBOL(sleep_on_timeout); 3975 3976#ifdef CONFIG_RT_MUTEXES 3977 3978/* 3979 * rt_mutex_setprio - set the current priority of a task 3980 * @p: task 3981 * @prio: prio value (kernel-internal form) 3982 * 3983 * This function changes the 'effective' priority of a task. It does 3984 * not touch ->normal_prio like __setscheduler(). 3985 * 3986 * Used by the rt_mutex code to implement priority inheritance logic. 3987 */ 3988void rt_mutex_setprio(struct task_struct *p, int prio) 3989{ 3990 int oldprio, on_rq, running; 3991 struct rq *rq; 3992 const struct sched_class *prev_class; 3993 3994 BUG_ON(prio < 0 || prio > MAX_PRIO); 3995 3996 rq = __task_rq_lock(p); 3997 3998 /* 3999 * Idle task boosting is a nono in general. There is one 4000 * exception, when PREEMPT_RT and NOHZ is active: 4001 * 4002 * The idle task calls get_next_timer_interrupt() and holds 4003 * the timer wheel base->lock on the CPU and another CPU wants 4004 * to access the timer (probably to cancel it). We can safely 4005 * ignore the boosting request, as the idle CPU runs this code 4006 * with interrupts disabled and will complete the lock 4007 * protected section without being interrupted. So there is no 4008 * real need to boost. 4009 */ 4010 if (unlikely(p == rq->idle)) { 4011 WARN_ON(p != rq->curr); 4012 WARN_ON(p->pi_blocked_on); 4013 goto out_unlock; 4014 } 4015 4016 trace_sched_pi_setprio(p, prio); 4017 oldprio = p->prio; 4018 prev_class = p->sched_class; 4019 on_rq = p->on_rq; 4020 running = task_current(rq, p); 4021 if (on_rq) 4022 dequeue_task(rq, p, 0); 4023 if (running) 4024 p->sched_class->put_prev_task(rq, p); 4025 4026 if (rt_prio(prio)) 4027 p->sched_class = &rt_sched_class; 4028 else 4029 p->sched_class = &fair_sched_class; 4030 4031 p->prio = prio; 4032 4033 if (running) 4034 p->sched_class->set_curr_task(rq); 4035 if (on_rq) 4036 enqueue_task(rq, p, oldprio < prio ? ENQUEUE_HEAD : 0); 4037 4038 check_class_changed(rq, p, prev_class, oldprio); 4039out_unlock: 4040 __task_rq_unlock(rq); 4041} 4042#endif 4043void set_user_nice(struct task_struct *p, long nice) 4044{ 4045 int old_prio, delta, on_rq; 4046 unsigned long flags; 4047 struct rq *rq; 4048 4049 if (TASK_NICE(p) == nice || nice < -20 || nice > 19) 4050 return; 4051 /* 4052 * We have to be careful, if called from sys_setpriority(), 4053 * the task might be in the middle of scheduling on another CPU. 4054 */ 4055 rq = task_rq_lock(p, &flags); 4056 /* 4057 * The RT priorities are set via sched_setscheduler(), but we still 4058 * allow the 'normal' nice value to be set - but as expected 4059 * it wont have any effect on scheduling until the task is 4060 * SCHED_FIFO/SCHED_RR: 4061 */ 4062 if (task_has_rt_policy(p)) { 4063 p->static_prio = NICE_TO_PRIO(nice); 4064 goto out_unlock; 4065 } 4066 on_rq = p->on_rq; 4067 if (on_rq) 4068 dequeue_task(rq, p, 0); 4069 4070 p->static_prio = NICE_TO_PRIO(nice); 4071 set_load_weight(p); 4072 old_prio = p->prio; 4073 p->prio = effective_prio(p); 4074 delta = p->prio - old_prio; 4075 4076 if (on_rq) { 4077 enqueue_task(rq, p, 0); 4078 /* 4079 * If the task increased its priority or is running and 4080 * lowered its priority, then reschedule its CPU: 4081 */ 4082 if (delta < 0 || (delta > 0 && task_running(rq, p))) 4083 resched_task(rq->curr); 4084 } 4085out_unlock: 4086 task_rq_unlock(rq, p, &flags); 4087} 4088EXPORT_SYMBOL(set_user_nice); 4089 4090/* 4091 * can_nice - check if a task can reduce its nice value 4092 * @p: task 4093 * @nice: nice value 4094 */ 4095int can_nice(const struct task_struct *p, const int nice) 4096{ 4097 /* convert nice value [19,-20] to rlimit style value [1,40] */ 4098 int nice_rlim = 20 - nice; 4099 4100 return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) || 4101 capable(CAP_SYS_NICE)); 4102} 4103 4104#ifdef __ARCH_WANT_SYS_NICE 4105 4106/* 4107 * sys_nice - change the priority of the current process. 4108 * @increment: priority increment 4109 * 4110 * sys_setpriority is a more generic, but much slower function that 4111 * does similar things. 4112 */ 4113SYSCALL_DEFINE1(nice, int, increment) 4114{ 4115 long nice, retval; 4116 4117 /* 4118 * Setpriority might change our priority at the same moment. 4119 * We don't have to worry. Conceptually one call occurs first 4120 * and we have a single winner. 4121 */ 4122 if (increment < -40) 4123 increment = -40; 4124 if (increment > 40) 4125 increment = 40; 4126 4127 nice = TASK_NICE(current) + increment; 4128 if (nice < -20) 4129 nice = -20; 4130 if (nice > 19) 4131 nice = 19; 4132 4133 if (increment < 0 && !can_nice(current, nice)) 4134 return -EPERM; 4135 4136 retval = security_task_setnice(current, nice); 4137 if (retval) 4138 return retval; 4139 4140 set_user_nice(current, nice); 4141 return 0; 4142} 4143 4144#endif 4145 4146/** 4147 * task_prio - return the priority value of a given task. 4148 * @p: the task in question. 4149 * 4150 * This is the priority value as seen by users in /proc. 4151 * RT tasks are offset by -200. Normal tasks are centered 4152 * around 0, value goes from -16 to +15. 4153 */ 4154int task_prio(const struct task_struct *p) 4155{ 4156 return p->prio - MAX_RT_PRIO; 4157} 4158 4159/** 4160 * task_nice - return the nice value of a given task. 4161 * @p: the task in question. 4162 */ 4163int task_nice(const struct task_struct *p) 4164{ 4165 return TASK_NICE(p); 4166} 4167EXPORT_SYMBOL(task_nice); 4168 4169/** 4170 * idle_cpu - is a given cpu idle currently? 4171 * @cpu: the processor in question. 4172 */ 4173int idle_cpu(int cpu) 4174{ 4175 struct rq *rq = cpu_rq(cpu); 4176 4177 if (rq->curr != rq->idle) 4178 return 0; 4179 4180 if (rq->nr_running) 4181 return 0; 4182 4183#ifdef CONFIG_SMP 4184 if (!llist_empty(&rq->wake_list)) 4185 return 0; 4186#endif 4187 4188 return 1; 4189} 4190 4191/** 4192 * idle_task - return the idle task for a given cpu. 4193 * @cpu: the processor in question. 4194 */ 4195struct task_struct *idle_task(int cpu) 4196{ 4197 return cpu_rq(cpu)->idle; 4198} 4199 4200/** 4201 * find_process_by_pid - find a process with a matching PID value. 4202 * @pid: the pid in question. 4203 */ 4204static struct task_struct *find_process_by_pid(pid_t pid) 4205{ 4206 return pid ? find_task_by_vpid(pid) : current; 4207} 4208 4209/* Actually do priority change: must hold rq lock. */ 4210static void 4211__setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio) 4212{ 4213 p->policy = policy; 4214 p->rt_priority = prio; 4215 p->normal_prio = normal_prio(p); 4216 /* we are holding p->pi_lock already */ 4217 p->prio = rt_mutex_getprio(p); 4218 if (rt_prio(p->prio)) 4219 p->sched_class = &rt_sched_class; 4220 else 4221 p->sched_class = &fair_sched_class; 4222 set_load_weight(p); 4223} 4224 4225/* 4226 * check the target process has a UID that matches the current process's 4227 */ 4228static bool check_same_owner(struct task_struct *p) 4229{ 4230 const struct cred *cred = current_cred(), *pcred; 4231 bool match; 4232 4233 rcu_read_lock(); 4234 pcred = __task_cred(p); 4235 match = (uid_eq(cred->euid, pcred->euid) || 4236 uid_eq(cred->euid, pcred->uid)); 4237 rcu_read_unlock(); 4238 return match; 4239} 4240 4241static int __sched_setscheduler(struct task_struct *p, int policy, 4242 const struct sched_param *param, bool user) 4243{ 4244 int retval, oldprio, oldpolicy = -1, on_rq, running; 4245 unsigned long flags; 4246 const struct sched_class *prev_class; 4247 struct rq *rq; 4248 int reset_on_fork; 4249 4250 /* may grab non-irq protected spin_locks */ 4251 BUG_ON(in_interrupt()); 4252recheck: 4253 /* double check policy once rq lock held */ 4254 if (policy < 0) { 4255 reset_on_fork = p->sched_reset_on_fork; 4256 policy = oldpolicy = p->policy; 4257 } else { 4258 reset_on_fork = !!(policy & SCHED_RESET_ON_FORK); 4259 policy &= ~SCHED_RESET_ON_FORK; 4260 4261 if (policy != SCHED_FIFO && policy != SCHED_RR && 4262 policy != SCHED_NORMAL && policy != SCHED_BATCH && 4263 policy != SCHED_IDLE) 4264 return -EINVAL; 4265 } 4266 4267 /* 4268 * Valid priorities for SCHED_FIFO and SCHED_RR are 4269 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL, 4270 * SCHED_BATCH and SCHED_IDLE is 0. 4271 */ 4272 if (param->sched_priority < 0 || 4273 (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) || 4274 (!p->mm && param->sched_priority > MAX_RT_PRIO-1)) 4275 return -EINVAL; 4276 if (rt_policy(policy) != (param->sched_priority != 0)) 4277 return -EINVAL; 4278 4279 /* 4280 * Allow unprivileged RT tasks to decrease priority: 4281 */ 4282 if (user && !capable(CAP_SYS_NICE)) { 4283 if (rt_policy(policy)) { 4284 unsigned long rlim_rtprio = 4285 task_rlimit(p, RLIMIT_RTPRIO); 4286 4287 /* can't set/change the rt policy */ 4288 if (policy != p->policy && !rlim_rtprio) 4289 return -EPERM; 4290 4291 /* can't increase priority */ 4292 if (param->sched_priority > p->rt_priority && 4293 param->sched_priority > rlim_rtprio) 4294 return -EPERM; 4295 } 4296 4297 /* 4298 * Treat SCHED_IDLE as nice 20. Only allow a switch to 4299 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it. 4300 */ 4301 if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) { 4302 if (!can_nice(p, TASK_NICE(p))) 4303 return -EPERM; 4304 } 4305 4306 /* can't change other user's priorities */ 4307 if (!check_same_owner(p)) 4308 return -EPERM; 4309 4310 /* Normal users shall not reset the sched_reset_on_fork flag */ 4311 if (p->sched_reset_on_fork && !reset_on_fork) 4312 return -EPERM; 4313 } 4314 4315 if (user) { 4316 retval = security_task_setscheduler(p); 4317 if (retval) 4318 return retval; 4319 } 4320 4321 /* 4322 * make sure no PI-waiters arrive (or leave) while we are 4323 * changing the priority of the task: 4324 * 4325 * To be able to change p->policy safely, the appropriate 4326 * runqueue lock must be held. 4327 */ 4328 rq = task_rq_lock(p, &flags); 4329 4330 /* 4331 * Changing the policy of the stop threads its a very bad idea 4332 */ 4333 if (p == rq->stop) { 4334 task_rq_unlock(rq, p, &flags); 4335 return -EINVAL; 4336 } 4337 4338 /* 4339 * If not changing anything there's no need to proceed further: 4340 */ 4341 if (unlikely(policy == p->policy && (!rt_policy(policy) || 4342 param->sched_priority == p->rt_priority))) { 4343 4344 __task_rq_unlock(rq); 4345 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 4346 return 0; 4347 } 4348 4349#ifdef CONFIG_RT_GROUP_SCHED 4350 if (user) { 4351 /* 4352 * Do not allow realtime tasks into groups that have no runtime 4353 * assigned. 4354 */ 4355 if (rt_bandwidth_enabled() && rt_policy(policy) && 4356 task_group(p)->rt_bandwidth.rt_runtime == 0 && 4357 !task_group_is_autogroup(task_group(p))) { 4358 task_rq_unlock(rq, p, &flags); 4359 return -EPERM; 4360 } 4361 } 4362#endif 4363 4364 /* recheck policy now with rq lock held */ 4365 if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { 4366 policy = oldpolicy = -1; 4367 task_rq_unlock(rq, p, &flags); 4368 goto recheck; 4369 } 4370 on_rq = p->on_rq; 4371 running = task_current(rq, p); 4372 if (on_rq) 4373 dequeue_task(rq, p, 0); 4374 if (running) 4375 p->sched_class->put_prev_task(rq, p); 4376 4377 p->sched_reset_on_fork = reset_on_fork; 4378 4379 oldprio = p->prio; 4380 prev_class = p->sched_class; 4381 __setscheduler(rq, p, policy, param->sched_priority); 4382 4383 if (running) 4384 p->sched_class->set_curr_task(rq); 4385 if (on_rq) 4386 enqueue_task(rq, p, 0); 4387 4388 check_class_changed(rq, p, prev_class, oldprio); 4389 task_rq_unlock(rq, p, &flags); 4390 4391 rt_mutex_adjust_pi(p); 4392 4393 return 0; 4394} 4395 4396/** 4397 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. 4398 * @p: the task in question. 4399 * @policy: new policy. 4400 * @param: structure containing the new RT priority. 4401 * 4402 * NOTE that the task may be already dead. 4403 */ 4404int sched_setscheduler(struct task_struct *p, int policy, 4405 const struct sched_param *param) 4406{ 4407 return __sched_setscheduler(p, policy, param, true); 4408} 4409EXPORT_SYMBOL_GPL(sched_setscheduler); 4410 4411/** 4412 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace. 4413 * @p: the task in question. 4414 * @policy: new policy. 4415 * @param: structure containing the new RT priority. 4416 * 4417 * Just like sched_setscheduler, only don't bother checking if the 4418 * current context has permission. For example, this is needed in 4419 * stop_machine(): we create temporary high priority worker threads, 4420 * but our caller might not have that capability. 4421 */ 4422int sched_setscheduler_nocheck(struct task_struct *p, int policy, 4423 const struct sched_param *param) 4424{ 4425 return __sched_setscheduler(p, policy, param, false); 4426} 4427 4428static int 4429do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) 4430{ 4431 struct sched_param lparam; 4432 struct task_struct *p; 4433 int retval; 4434 4435 if (!param || pid < 0) 4436 return -EINVAL; 4437 if (copy_from_user(&lparam, param, sizeof(struct sched_param))) 4438 return -EFAULT; 4439 4440 rcu_read_lock(); 4441 retval = -ESRCH; 4442 p = find_process_by_pid(pid); 4443 if (p != NULL) 4444 retval = sched_setscheduler(p, policy, &lparam); 4445 rcu_read_unlock(); 4446 4447 return retval; 4448} 4449 4450/** 4451 * sys_sched_setscheduler - set/change the scheduler policy and RT priority 4452 * @pid: the pid in question. 4453 * @policy: new policy. 4454 * @param: structure containing the new RT priority. 4455 */ 4456SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy, 4457 struct sched_param __user *, param) 4458{ 4459 /* negative values for policy are not valid */ 4460 if (policy < 0) 4461 return -EINVAL; 4462 4463 return do_sched_setscheduler(pid, policy, param); 4464} 4465 4466/** 4467 * sys_sched_setparam - set/change the RT priority of a thread 4468 * @pid: the pid in question. 4469 * @param: structure containing the new RT priority. 4470 */ 4471SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param) 4472{ 4473 return do_sched_setscheduler(pid, -1, param); 4474} 4475 4476/** 4477 * sys_sched_getscheduler - get the policy (scheduling class) of a thread 4478 * @pid: the pid in question. 4479 */ 4480SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid) 4481{ 4482 struct task_struct *p; 4483 int retval; 4484 4485 if (pid < 0) 4486 return -EINVAL; 4487 4488 retval = -ESRCH; 4489 rcu_read_lock(); 4490 p = find_process_by_pid(pid); 4491 if (p) { 4492 retval = security_task_getscheduler(p); 4493 if (!retval) 4494 retval = p->policy 4495 | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0); 4496 } 4497 rcu_read_unlock(); 4498 return retval; 4499} 4500 4501/** 4502 * sys_sched_getparam - get the RT priority of a thread 4503 * @pid: the pid in question. 4504 * @param: structure containing the RT priority. 4505 */ 4506SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param) 4507{ 4508 struct sched_param lp; 4509 struct task_struct *p; 4510 int retval; 4511 4512 if (!param || pid < 0) 4513 return -EINVAL; 4514 4515 rcu_read_lock(); 4516 p = find_process_by_pid(pid); 4517 retval = -ESRCH; 4518 if (!p) 4519 goto out_unlock; 4520 4521 retval = security_task_getscheduler(p); 4522 if (retval) 4523 goto out_unlock; 4524 4525 lp.sched_priority = p->rt_priority; 4526 rcu_read_unlock(); 4527 4528 /* 4529 * This one might sleep, we cannot do it with a spinlock held ... 4530 */ 4531 retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; 4532 4533 return retval; 4534 4535out_unlock: 4536 rcu_read_unlock(); 4537 return retval; 4538} 4539 4540long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) 4541{ 4542 cpumask_var_t cpus_allowed, new_mask; 4543 struct task_struct *p; 4544 int retval; 4545 4546 get_online_cpus(); 4547 rcu_read_lock(); 4548 4549 p = find_process_by_pid(pid); 4550 if (!p) { 4551 rcu_read_unlock(); 4552 put_online_cpus(); 4553 return -ESRCH; 4554 } 4555 4556 /* Prevent p going away */ 4557 get_task_struct(p); 4558 rcu_read_unlock(); 4559 4560 if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) { 4561 retval = -ENOMEM; 4562 goto out_put_task; 4563 } 4564 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) { 4565 retval = -ENOMEM; 4566 goto out_free_cpus_allowed; 4567 } 4568 retval = -EPERM; 4569 if (!check_same_owner(p) && !ns_capable(task_user_ns(p), CAP_SYS_NICE)) 4570 goto out_unlock; 4571 4572 retval = security_task_setscheduler(p); 4573 if (retval) 4574 goto out_unlock; 4575 4576 cpuset_cpus_allowed(p, cpus_allowed); 4577 cpumask_and(new_mask, in_mask, cpus_allowed); 4578again: 4579 retval = set_cpus_allowed_ptr(p, new_mask); 4580 4581 if (!retval) { 4582 cpuset_cpus_allowed(p, cpus_allowed); 4583 if (!cpumask_subset(new_mask, cpus_allowed)) { 4584 /* 4585 * We must have raced with a concurrent cpuset 4586 * update. Just reset the cpus_allowed to the 4587 * cpuset's cpus_allowed 4588 */ 4589 cpumask_copy(new_mask, cpus_allowed); 4590 goto again; 4591 } 4592 } 4593out_unlock: 4594 free_cpumask_var(new_mask); 4595out_free_cpus_allowed: 4596 free_cpumask_var(cpus_allowed); 4597out_put_task: 4598 put_task_struct(p); 4599 put_online_cpus(); 4600 return retval; 4601} 4602 4603static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, 4604 struct cpumask *new_mask) 4605{ 4606 if (len < cpumask_size()) 4607 cpumask_clear(new_mask); 4608 else if (len > cpumask_size()) 4609 len = cpumask_size(); 4610 4611 return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; 4612} 4613 4614/** 4615 * sys_sched_setaffinity - set the cpu affinity of a process 4616 * @pid: pid of the process 4617 * @len: length in bytes of the bitmask pointed to by user_mask_ptr 4618 * @user_mask_ptr: user-space pointer to the new cpu mask 4619 */ 4620SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len, 4621 unsigned long __user *, user_mask_ptr) 4622{ 4623 cpumask_var_t new_mask; 4624 int retval; 4625 4626 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) 4627 return -ENOMEM; 4628 4629 retval = get_user_cpu_mask(user_mask_ptr, len, new_mask); 4630 if (retval == 0) 4631 retval = sched_setaffinity(pid, new_mask); 4632 free_cpumask_var(new_mask); 4633 return retval; 4634} 4635 4636long sched_getaffinity(pid_t pid, struct cpumask *mask) 4637{ 4638 struct task_struct *p; 4639 unsigned long flags; 4640 int retval; 4641 4642 get_online_cpus(); 4643 rcu_read_lock(); 4644 4645 retval = -ESRCH; 4646 p = find_process_by_pid(pid); 4647 if (!p) 4648 goto out_unlock; 4649 4650 retval = security_task_getscheduler(p); 4651 if (retval) 4652 goto out_unlock; 4653 4654 raw_spin_lock_irqsave(&p->pi_lock, flags); 4655 cpumask_and(mask, &p->cpus_allowed, cpu_online_mask); 4656 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 4657 4658out_unlock: 4659 rcu_read_unlock(); 4660 put_online_cpus(); 4661 4662 return retval; 4663} 4664 4665/** 4666 * sys_sched_getaffinity - get the cpu affinity of a process 4667 * @pid: pid of the process 4668 * @len: length in bytes of the bitmask pointed to by user_mask_ptr 4669 * @user_mask_ptr: user-space pointer to hold the current cpu mask 4670 */ 4671SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len, 4672 unsigned long __user *, user_mask_ptr) 4673{ 4674 int ret; 4675 cpumask_var_t mask; 4676 4677 if ((len * BITS_PER_BYTE) < nr_cpu_ids) 4678 return -EINVAL; 4679 if (len & (sizeof(unsigned long)-1)) 4680 return -EINVAL; 4681 4682 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) 4683 return -ENOMEM; 4684 4685 ret = sched_getaffinity(pid, mask); 4686 if (ret == 0) { 4687 size_t retlen = min_t(size_t, len, cpumask_size()); 4688 4689 if (copy_to_user(user_mask_ptr, mask, retlen)) 4690 ret = -EFAULT; 4691 else 4692 ret = retlen; 4693 } 4694 free_cpumask_var(mask); 4695 4696 return ret; 4697} 4698 4699/** 4700 * sys_sched_yield - yield the current processor to other threads. 4701 * 4702 * This function yields the current CPU to other tasks. If there are no 4703 * other threads running on this CPU then this function will return. 4704 */ 4705SYSCALL_DEFINE0(sched_yield) 4706{ 4707 struct rq *rq = this_rq_lock(); 4708 4709 schedstat_inc(rq, yld_count); 4710 current->sched_class->yield_task(rq); 4711 4712 /* 4713 * Since we are going to call schedule() anyway, there's 4714 * no need to preempt or enable interrupts: 4715 */ 4716 __release(rq->lock); 4717 spin_release(&rq->lock.dep_map, 1, _THIS_IP_); 4718 do_raw_spin_unlock(&rq->lock); 4719 sched_preempt_enable_no_resched(); 4720 4721 schedule(); 4722 4723 return 0; 4724} 4725 4726static inline int should_resched(void) 4727{ 4728 return need_resched() && !(preempt_count() & PREEMPT_ACTIVE); 4729} 4730 4731static void __cond_resched(void) 4732{ 4733 add_preempt_count(PREEMPT_ACTIVE); 4734 __schedule(); 4735 sub_preempt_count(PREEMPT_ACTIVE); 4736} 4737 4738int __sched _cond_resched(void) 4739{ 4740 if (should_resched()) { 4741 __cond_resched(); 4742 return 1; 4743 } 4744 return 0; 4745} 4746EXPORT_SYMBOL(_cond_resched); 4747 4748/* 4749 * __cond_resched_lock() - if a reschedule is pending, drop the given lock, 4750 * call schedule, and on return reacquire the lock. 4751 * 4752 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level 4753 * operations here to prevent schedule() from being called twice (once via 4754 * spin_unlock(), once by hand). 4755 */ 4756int __cond_resched_lock(spinlock_t *lock) 4757{ 4758 int resched = should_resched(); 4759 int ret = 0; 4760 4761 lockdep_assert_held(lock); 4762 4763 if (spin_needbreak(lock) || resched) { 4764 spin_unlock(lock); 4765 if (resched) 4766 __cond_resched(); 4767 else 4768 cpu_relax(); 4769 ret = 1; 4770 spin_lock(lock); 4771 } 4772 return ret; 4773} 4774EXPORT_SYMBOL(__cond_resched_lock); 4775 4776int __sched __cond_resched_softirq(void) 4777{ 4778 BUG_ON(!in_softirq()); 4779 4780 if (should_resched()) { 4781 local_bh_enable(); 4782 __cond_resched(); 4783 local_bh_disable(); 4784 return 1; 4785 } 4786 return 0; 4787} 4788EXPORT_SYMBOL(__cond_resched_softirq); 4789 4790/** 4791 * yield - yield the current processor to other threads. 4792 * 4793 * Do not ever use this function, there's a 99% chance you're doing it wrong. 4794 * 4795 * The scheduler is at all times free to pick the calling task as the most 4796 * eligible task to run, if removing the yield() call from your code breaks 4797 * it, its already broken. 4798 * 4799 * Typical broken usage is: 4800 * 4801 * while (!event) 4802 * yield(); 4803 * 4804 * where one assumes that yield() will let 'the other' process run that will 4805 * make event true. If the current task is a SCHED_FIFO task that will never 4806 * happen. Never use yield() as a progress guarantee!! 4807 * 4808 * If you want to use yield() to wait for something, use wait_event(). 4809 * If you want to use yield() to be 'nice' for others, use cond_resched(). 4810 * If you still want to use yield(), do not! 4811 */ 4812void __sched yield(void) 4813{ 4814 set_current_state(TASK_RUNNING); 4815 sys_sched_yield(); 4816} 4817EXPORT_SYMBOL(yield); 4818 4819/** 4820 * yield_to - yield the current processor to another thread in 4821 * your thread group, or accelerate that thread toward the 4822 * processor it's on. 4823 * @p: target task 4824 * @preempt: whether task preemption is allowed or not 4825 * 4826 * It's the caller's job to ensure that the target task struct 4827 * can't go away on us before we can do any checks. 4828 * 4829 * Returns true if we indeed boosted the target task. 4830 */ 4831bool __sched yield_to(struct task_struct *p, bool preempt) 4832{ 4833 struct task_struct *curr = current; 4834 struct rq *rq, *p_rq; 4835 unsigned long flags; 4836 bool yielded = 0; 4837 4838 local_irq_save(flags); 4839 rq = this_rq(); 4840 4841again: 4842 p_rq = task_rq(p); 4843 double_rq_lock(rq, p_rq); 4844 while (task_rq(p) != p_rq) { 4845 double_rq_unlock(rq, p_rq); 4846 goto again; 4847 } 4848 4849 if (!curr->sched_class->yield_to_task) 4850 goto out; 4851 4852 if (curr->sched_class != p->sched_class) 4853 goto out; 4854 4855 if (task_running(p_rq, p) || p->state) 4856 goto out; 4857 4858 yielded = curr->sched_class->yield_to_task(rq, p, preempt); 4859 if (yielded) { 4860 schedstat_inc(rq, yld_count); 4861 /* 4862 * Make p's CPU reschedule; pick_next_entity takes care of 4863 * fairness. 4864 */ 4865 if (preempt && rq != p_rq) 4866 resched_task(p_rq->curr); 4867 } else { 4868 /* 4869 * We might have set it in task_yield_fair(), but are 4870 * not going to schedule(), so don't want to skip 4871 * the next update. 4872 */ 4873 rq->skip_clock_update = 0; 4874 } 4875 4876out: 4877 double_rq_unlock(rq, p_rq); 4878 local_irq_restore(flags); 4879 4880 if (yielded) 4881 schedule(); 4882 4883 return yielded; 4884} 4885EXPORT_SYMBOL_GPL(yield_to); 4886 4887/* 4888 * This task is about to go to sleep on IO. Increment rq->nr_iowait so 4889 * that process accounting knows that this is a task in IO wait state. 4890 */ 4891void __sched io_schedule(void) 4892{ 4893 struct rq *rq = raw_rq(); 4894 4895 delayacct_blkio_start(); 4896 atomic_inc(&rq->nr_iowait); 4897 blk_flush_plug(current); 4898 current->in_iowait = 1; 4899 schedule(); 4900 current->in_iowait = 0; 4901 atomic_dec(&rq->nr_iowait); 4902 delayacct_blkio_end(); 4903} 4904EXPORT_SYMBOL(io_schedule); 4905 4906long __sched io_schedule_timeout(long timeout) 4907{ 4908 struct rq *rq = raw_rq(); 4909 long ret; 4910 4911 delayacct_blkio_start(); 4912 atomic_inc(&rq->nr_iowait); 4913 blk_flush_plug(current); 4914 current->in_iowait = 1; 4915 ret = schedule_timeout(timeout); 4916 current->in_iowait = 0; 4917 atomic_dec(&rq->nr_iowait); 4918 delayacct_blkio_end(); 4919 return ret; 4920} 4921 4922/** 4923 * sys_sched_get_priority_max - return maximum RT priority. 4924 * @policy: scheduling class. 4925 * 4926 * this syscall returns the maximum rt_priority that can be used 4927 * by a given scheduling class. 4928 */ 4929SYSCALL_DEFINE1(sched_get_priority_max, int, policy) 4930{ 4931 int ret = -EINVAL; 4932 4933 switch (policy) { 4934 case SCHED_FIFO: 4935 case SCHED_RR: 4936 ret = MAX_USER_RT_PRIO-1; 4937 break; 4938 case SCHED_NORMAL: 4939 case SCHED_BATCH: 4940 case SCHED_IDLE: 4941 ret = 0; 4942 break; 4943 } 4944 return ret; 4945} 4946 4947/** 4948 * sys_sched_get_priority_min - return minimum RT priority. 4949 * @policy: scheduling class. 4950 * 4951 * this syscall returns the minimum rt_priority that can be used 4952 * by a given scheduling class. 4953 */ 4954SYSCALL_DEFINE1(sched_get_priority_min, int, policy) 4955{ 4956 int ret = -EINVAL; 4957 4958 switch (policy) { 4959 case SCHED_FIFO: 4960 case SCHED_RR: 4961 ret = 1; 4962 break; 4963 case SCHED_NORMAL: 4964 case SCHED_BATCH: 4965 case SCHED_IDLE: 4966 ret = 0; 4967 } 4968 return ret; 4969} 4970 4971/** 4972 * sys_sched_rr_get_interval - return the default timeslice of a process. 4973 * @pid: pid of the process. 4974 * @interval: userspace pointer to the timeslice value. 4975 * 4976 * this syscall writes the default timeslice value of a given process 4977 * into the user-space timespec buffer. A value of '0' means infinity. 4978 */ 4979SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid, 4980 struct timespec __user *, interval) 4981{ 4982 struct task_struct *p; 4983 unsigned int time_slice; 4984 unsigned long flags; 4985 struct rq *rq; 4986 int retval; 4987 struct timespec t; 4988 4989 if (pid < 0) 4990 return -EINVAL; 4991 4992 retval = -ESRCH; 4993 rcu_read_lock(); 4994 p = find_process_by_pid(pid); 4995 if (!p) 4996 goto out_unlock; 4997 4998 retval = security_task_getscheduler(p); 4999 if (retval) 5000 goto out_unlock; 5001 5002 rq = task_rq_lock(p, &flags); 5003 time_slice = p->sched_class->get_rr_interval(rq, p); 5004 task_rq_unlock(rq, p, &flags); 5005 5006 rcu_read_unlock(); 5007 jiffies_to_timespec(time_slice, &t); 5008 retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; 5009 return retval; 5010 5011out_unlock: 5012 rcu_read_unlock(); 5013 return retval; 5014} 5015 5016static const char stat_nam[] = TASK_STATE_TO_CHAR_STR; 5017 5018void sched_show_task(struct task_struct *p) 5019{ 5020 unsigned long free = 0; 5021 unsigned state; 5022 5023 state = p->state ? __ffs(p->state) + 1 : 0; 5024 printk(KERN_INFO "%-15.15s %c", p->comm, 5025 state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); 5026#if BITS_PER_LONG == 32 5027 if (state == TASK_RUNNING) 5028 printk(KERN_CONT " running "); 5029 else 5030 printk(KERN_CONT " %08lx ", thread_saved_pc(p)); 5031#else 5032 if (state == TASK_RUNNING) 5033 printk(KERN_CONT " running task "); 5034 else 5035 printk(KERN_CONT " %016lx ", thread_saved_pc(p)); 5036#endif 5037#ifdef CONFIG_DEBUG_STACK_USAGE 5038 free = stack_not_used(p); 5039#endif 5040 printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free, 5041 task_pid_nr(p), task_pid_nr(rcu_dereference(p->real_parent)), 5042 (unsigned long)task_thread_info(p)->flags); 5043 5044 show_stack(p, NULL); 5045} 5046 5047void show_state_filter(unsigned long state_filter) 5048{ 5049 struct task_struct *g, *p; 5050 5051#if BITS_PER_LONG == 32 5052 printk(KERN_INFO 5053 " task PC stack pid father\n"); 5054#else 5055 printk(KERN_INFO 5056 " task PC stack pid father\n"); 5057#endif 5058 rcu_read_lock(); 5059 do_each_thread(g, p) { 5060 /* 5061 * reset the NMI-timeout, listing all files on a slow 5062 * console might take a lot of time: 5063 */ 5064 touch_nmi_watchdog(); 5065 if (!state_filter || (p->state & state_filter)) 5066 sched_show_task(p); 5067 } while_each_thread(g, p); 5068 5069 touch_all_softlockup_watchdogs(); 5070 5071#ifdef CONFIG_SCHED_DEBUG 5072 sysrq_sched_debug_show(); 5073#endif 5074 rcu_read_unlock(); 5075 /* 5076 * Only show locks if all tasks are dumped: 5077 */ 5078 if (!state_filter) 5079 debug_show_all_locks(); 5080} 5081 5082void __cpuinit init_idle_bootup_task(struct task_struct *idle) 5083{ 5084 idle->sched_class = &idle_sched_class; 5085} 5086 5087/** 5088 * init_idle - set up an idle thread for a given CPU 5089 * @idle: task in question 5090 * @cpu: cpu the idle task belongs to 5091 * 5092 * NOTE: this function does not set the idle thread's NEED_RESCHED 5093 * flag, to make booting more robust. 5094 */ 5095void __cpuinit init_idle(struct task_struct *idle, int cpu) 5096{ 5097 struct rq *rq = cpu_rq(cpu); 5098 unsigned long flags; 5099 5100 raw_spin_lock_irqsave(&rq->lock, flags); 5101 5102 __sched_fork(idle); 5103 idle->state = TASK_RUNNING; 5104 idle->se.exec_start = sched_clock(); 5105 5106 do_set_cpus_allowed(idle, cpumask_of(cpu)); 5107 /* 5108 * We're having a chicken and egg problem, even though we are 5109 * holding rq->lock, the cpu isn't yet set to this cpu so the 5110 * lockdep check in task_group() will fail. 5111 * 5112 * Similar case to sched_fork(). / Alternatively we could 5113 * use task_rq_lock() here and obtain the other rq->lock. 5114 * 5115 * Silence PROVE_RCU 5116 */ 5117 rcu_read_lock(); 5118 __set_task_cpu(idle, cpu); 5119 rcu_read_unlock(); 5120 5121 rq->curr = rq->idle = idle; 5122#if defined(CONFIG_SMP) 5123 idle->on_cpu = 1; 5124#endif 5125 raw_spin_unlock_irqrestore(&rq->lock, flags); 5126 5127 /* Set the preempt count _outside_ the spinlocks! */ 5128 task_thread_info(idle)->preempt_count = 0; 5129 5130 /* 5131 * The idle tasks have their own, simple scheduling class: 5132 */ 5133 idle->sched_class = &idle_sched_class; 5134 ftrace_graph_init_idle_task(idle, cpu); 5135#if defined(CONFIG_SMP) 5136 sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu); 5137#endif 5138} 5139 5140#ifdef CONFIG_SMP 5141void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) 5142{ 5143 if (p->sched_class && p->sched_class->set_cpus_allowed) 5144 p->sched_class->set_cpus_allowed(p, new_mask); 5145 5146 cpumask_copy(&p->cpus_allowed, new_mask); 5147 p->nr_cpus_allowed = cpumask_weight(new_mask); 5148} 5149 5150/* 5151 * This is how migration works: 5152 * 5153 * 1) we invoke migration_cpu_stop() on the target CPU using 5154 * stop_one_cpu(). 5155 * 2) stopper starts to run (implicitly forcing the migrated thread 5156 * off the CPU) 5157 * 3) it checks whether the migrated task is still in the wrong runqueue. 5158 * 4) if it's in the wrong runqueue then the migration thread removes 5159 * it and puts it into the right queue. 5160 * 5) stopper completes and stop_one_cpu() returns and the migration 5161 * is done. 5162 */ 5163 5164/* 5165 * Change a given task's CPU affinity. Migrate the thread to a 5166 * proper CPU and schedule it away if the CPU it's executing on 5167 * is removed from the allowed bitmask. 5168 * 5169 * NOTE: the caller must have a valid reference to the task, the 5170 * task must not exit() & deallocate itself prematurely. The 5171 * call is not atomic; no spinlocks may be held. 5172 */ 5173int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) 5174{ 5175 unsigned long flags; 5176 struct rq *rq; 5177 unsigned int dest_cpu; 5178 int ret = 0; 5179 5180 rq = task_rq_lock(p, &flags); 5181 5182 if (cpumask_equal(&p->cpus_allowed, new_mask)) 5183 goto out; 5184 5185 if (!cpumask_intersects(new_mask, cpu_active_mask)) { 5186 ret = -EINVAL; 5187 goto out; 5188 } 5189 5190 if (unlikely((p->flags & PF_THREAD_BOUND) && p != current)) { 5191 ret = -EINVAL; 5192 goto out; 5193 } 5194 5195 do_set_cpus_allowed(p, new_mask); 5196 5197 /* Can the task run on the task's current CPU? If so, we're done */ 5198 if (cpumask_test_cpu(task_cpu(p), new_mask)) 5199 goto out; 5200 5201 dest_cpu = cpumask_any_and(cpu_active_mask, new_mask); 5202 if (p->on_rq) { 5203 struct migration_arg arg = { p, dest_cpu }; 5204 /* Need help from migration thread: drop lock and wait. */ 5205 task_rq_unlock(rq, p, &flags); 5206 stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg); 5207 tlb_migrate_finish(p->mm); 5208 return 0; 5209 } 5210out: 5211 task_rq_unlock(rq, p, &flags); 5212 5213 return ret; 5214} 5215EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr); 5216 5217/* 5218 * Move (not current) task off this cpu, onto dest cpu. We're doing 5219 * this because either it can't run here any more (set_cpus_allowed() 5220 * away from this CPU, or CPU going down), or because we're 5221 * attempting to rebalance this task on exec (sched_exec). 5222 * 5223 * So we race with normal scheduler movements, but that's OK, as long 5224 * as the task is no longer on this CPU. 5225 * 5226 * Returns non-zero if task was successfully migrated. 5227 */ 5228static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) 5229{ 5230 struct rq *rq_dest, *rq_src; 5231 int ret = 0; 5232 5233 if (unlikely(!cpu_active(dest_cpu))) 5234 return ret; 5235 5236 rq_src = cpu_rq(src_cpu); 5237 rq_dest = cpu_rq(dest_cpu); 5238 5239 raw_spin_lock(&p->pi_lock); 5240 double_rq_lock(rq_src, rq_dest); 5241 /* Already moved. */ 5242 if (task_cpu(p) != src_cpu) 5243 goto done; 5244 /* Affinity changed (again). */ 5245 if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) 5246 goto fail; 5247 5248 /* 5249 * If we're not on a rq, the next wake-up will ensure we're 5250 * placed properly. 5251 */ 5252 if (p->on_rq) { 5253 dequeue_task(rq_src, p, 0); 5254 set_task_cpu(p, dest_cpu); 5255 enqueue_task(rq_dest, p, 0); 5256 check_preempt_curr(rq_dest, p, 0); 5257 } 5258done: 5259 ret = 1; 5260fail: 5261 double_rq_unlock(rq_src, rq_dest); 5262 raw_spin_unlock(&p->pi_lock); 5263 return ret; 5264} 5265 5266/* 5267 * migration_cpu_stop - this will be executed by a highprio stopper thread 5268 * and performs thread migration by bumping thread off CPU then 5269 * 'pushing' onto another runqueue. 5270 */ 5271static int migration_cpu_stop(void *data) 5272{ 5273 struct migration_arg *arg = data; 5274 5275 /* 5276 * The original target cpu might have gone down and we might 5277 * be on another cpu but it doesn't matter. 5278 */ 5279 local_irq_disable(); 5280 __migrate_task(arg->task, raw_smp_processor_id(), arg->dest_cpu); 5281 local_irq_enable(); 5282 return 0; 5283} 5284 5285#ifdef CONFIG_HOTPLUG_CPU 5286 5287/* 5288 * Ensures that the idle task is using init_mm right before its cpu goes 5289 * offline. 5290 */ 5291void idle_task_exit(void) 5292{ 5293 struct mm_struct *mm = current->active_mm; 5294 5295 BUG_ON(cpu_online(smp_processor_id())); 5296 5297 if (mm != &init_mm) 5298 switch_mm(mm, &init_mm, current); 5299 mmdrop(mm); 5300} 5301 5302/* 5303 * While a dead CPU has no uninterruptible tasks queued at this point, 5304 * it might still have a nonzero ->nr_uninterruptible counter, because 5305 * for performance reasons the counter is not stricly tracking tasks to 5306 * their home CPUs. So we just add the counter to another CPU's counter, 5307 * to keep the global sum constant after CPU-down: 5308 */ 5309static void migrate_nr_uninterruptible(struct rq *rq_src) 5310{ 5311 struct rq *rq_dest = cpu_rq(cpumask_any(cpu_active_mask)); 5312 5313 rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible; 5314 rq_src->nr_uninterruptible = 0; 5315} 5316 5317/* 5318 * remove the tasks which were accounted by rq from calc_load_tasks. 5319 */ 5320static void calc_global_load_remove(struct rq *rq) 5321{ 5322 atomic_long_sub(rq->calc_load_active, &calc_load_tasks); 5323 rq->calc_load_active = 0; 5324} 5325 5326/* 5327 * Migrate all tasks from the rq, sleeping tasks will be migrated by 5328 * try_to_wake_up()->select_task_rq(). 5329 * 5330 * Called with rq->lock held even though we'er in stop_machine() and 5331 * there's no concurrency possible, we hold the required locks anyway 5332 * because of lock validation efforts. 5333 */ 5334static void migrate_tasks(unsigned int dead_cpu) 5335{ 5336 struct rq *rq = cpu_rq(dead_cpu); 5337 struct task_struct *next, *stop = rq->stop; 5338 int dest_cpu; 5339 5340 /* 5341 * Fudge the rq selection such that the below task selection loop 5342 * doesn't get stuck on the currently eligible stop task. 5343 * 5344 * We're currently inside stop_machine() and the rq is either stuck 5345 * in the stop_machine_cpu_stop() loop, or we're executing this code, 5346 * either way we should never end up calling schedule() until we're 5347 * done here. 5348 */ 5349 rq->stop = NULL; 5350 5351 /* Ensure any throttled groups are reachable by pick_next_task */ 5352 unthrottle_offline_cfs_rqs(rq); 5353 5354 for ( ; ; ) { 5355 /* 5356 * There's this thread running, bail when that's the only 5357 * remaining thread. 5358 */ 5359 if (rq->nr_running == 1) 5360 break; 5361 5362 next = pick_next_task(rq); 5363 BUG_ON(!next); 5364 next->sched_class->put_prev_task(rq, next); 5365 5366 /* Find suitable destination for @next, with force if needed. */ 5367 dest_cpu = select_fallback_rq(dead_cpu, next); 5368 raw_spin_unlock(&rq->lock); 5369 5370 __migrate_task(next, dead_cpu, dest_cpu); 5371 5372 raw_spin_lock(&rq->lock); 5373 } 5374 5375 rq->stop = stop; 5376} 5377 5378#endif /* CONFIG_HOTPLUG_CPU */ 5379 5380#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL) 5381 5382static struct ctl_table sd_ctl_dir[] = { 5383 { 5384 .procname = "sched_domain", 5385 .mode = 0555, 5386 }, 5387 {} 5388}; 5389 5390static struct ctl_table sd_ctl_root[] = { 5391 { 5392 .procname = "kernel", 5393 .mode = 0555, 5394 .child = sd_ctl_dir, 5395 }, 5396 {} 5397}; 5398 5399static struct ctl_table *sd_alloc_ctl_entry(int n) 5400{ 5401 struct ctl_table *entry = 5402 kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL); 5403 5404 return entry; 5405} 5406 5407static void sd_free_ctl_entry(struct ctl_table **tablep) 5408{ 5409 struct ctl_table *entry; 5410 5411 /* 5412 * In the intermediate directories, both the child directory and 5413 * procname are dynamically allocated and could fail but the mode 5414 * will always be set. In the lowest directory the names are 5415 * static strings and all have proc handlers. 5416 */ 5417 for (entry = *tablep; entry->mode; entry++) { 5418 if (entry->child) 5419 sd_free_ctl_entry(&entry->child); 5420 if (entry->proc_handler == NULL) 5421 kfree(entry->procname); 5422 } 5423 5424 kfree(*tablep); 5425 *tablep = NULL; 5426} 5427 5428static void 5429set_table_entry(struct ctl_table *entry, 5430 const char *procname, void *data, int maxlen, 5431 umode_t mode, proc_handler *proc_handler) 5432{ 5433 entry->procname = procname; 5434 entry->data = data; 5435 entry->maxlen = maxlen; 5436 entry->mode = mode; 5437 entry->proc_handler = proc_handler; 5438} 5439 5440static struct ctl_table * 5441sd_alloc_ctl_domain_table(struct sched_domain *sd) 5442{ 5443 struct ctl_table *table = sd_alloc_ctl_entry(13); 5444 5445 if (table == NULL) 5446 return NULL; 5447 5448 set_table_entry(&table[0], "min_interval", &sd->min_interval, 5449 sizeof(long), 0644, proc_doulongvec_minmax); 5450 set_table_entry(&table[1], "max_interval", &sd->max_interval, 5451 sizeof(long), 0644, proc_doulongvec_minmax); 5452 set_table_entry(&table[2], "busy_idx", &sd->busy_idx, 5453 sizeof(int), 0644, proc_dointvec_minmax); 5454 set_table_entry(&table[3], "idle_idx", &sd->idle_idx, 5455 sizeof(int), 0644, proc_dointvec_minmax); 5456 set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx, 5457 sizeof(int), 0644, proc_dointvec_minmax); 5458 set_table_entry(&table[5], "wake_idx", &sd->wake_idx, 5459 sizeof(int), 0644, proc_dointvec_minmax); 5460 set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx, 5461 sizeof(int), 0644, proc_dointvec_minmax); 5462 set_table_entry(&table[7], "busy_factor", &sd->busy_factor, 5463 sizeof(int), 0644, proc_dointvec_minmax); 5464 set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct, 5465 sizeof(int), 0644, proc_dointvec_minmax); 5466 set_table_entry(&table[9], "cache_nice_tries", 5467 &sd->cache_nice_tries, 5468 sizeof(int), 0644, proc_dointvec_minmax); 5469 set_table_entry(&table[10], "flags", &sd->flags, 5470 sizeof(int), 0644, proc_dointvec_minmax); 5471 set_table_entry(&table[11], "name", sd->name, 5472 CORENAME_MAX_SIZE, 0444, proc_dostring); 5473 /* &table[12] is terminator */ 5474 5475 return table; 5476} 5477 5478static ctl_table *sd_alloc_ctl_cpu_table(int cpu) 5479{ 5480 struct ctl_table *entry, *table; 5481 struct sched_domain *sd; 5482 int domain_num = 0, i; 5483 char buf[32]; 5484 5485 for_each_domain(cpu, sd) 5486 domain_num++; 5487 entry = table = sd_alloc_ctl_entry(domain_num + 1); 5488 if (table == NULL) 5489 return NULL; 5490 5491 i = 0; 5492 for_each_domain(cpu, sd) { 5493 snprintf(buf, 32, "domain%d", i); 5494 entry->procname = kstrdup(buf, GFP_KERNEL); 5495 entry->mode = 0555; 5496 entry->child = sd_alloc_ctl_domain_table(sd); 5497 entry++; 5498 i++; 5499 } 5500 return table; 5501} 5502 5503static struct ctl_table_header *sd_sysctl_header; 5504static void register_sched_domain_sysctl(void) 5505{ 5506 int i, cpu_num = num_possible_cpus(); 5507 struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1); 5508 char buf[32]; 5509 5510 WARN_ON(sd_ctl_dir[0].child); 5511 sd_ctl_dir[0].child = entry; 5512 5513 if (entry == NULL) 5514 return; 5515 5516 for_each_possible_cpu(i) { 5517 snprintf(buf, 32, "cpu%d", i); 5518 entry->procname = kstrdup(buf, GFP_KERNEL); 5519 entry->mode = 0555; 5520 entry->child = sd_alloc_ctl_cpu_table(i); 5521 entry++; 5522 } 5523 5524 WARN_ON(sd_sysctl_header); 5525 sd_sysctl_header = register_sysctl_table(sd_ctl_root); 5526} 5527 5528/* may be called multiple times per register */ 5529static void unregister_sched_domain_sysctl(void) 5530{ 5531 if (sd_sysctl_header) 5532 unregister_sysctl_table(sd_sysctl_header); 5533 sd_sysctl_header = NULL; 5534 if (sd_ctl_dir[0].child) 5535 sd_free_ctl_entry(&sd_ctl_dir[0].child); 5536} 5537#else 5538static void register_sched_domain_sysctl(void) 5539{ 5540} 5541static void unregister_sched_domain_sysctl(void) 5542{ 5543} 5544#endif 5545 5546static void set_rq_online(struct rq *rq) 5547{ 5548 if (!rq->online) { 5549 const struct sched_class *class; 5550 5551 cpumask_set_cpu(rq->cpu, rq->rd->online); 5552 rq->online = 1; 5553 5554 for_each_class(class) { 5555 if (class->rq_online) 5556 class->rq_online(rq); 5557 } 5558 } 5559} 5560 5561static void set_rq_offline(struct rq *rq) 5562{ 5563 if (rq->online) { 5564 const struct sched_class *class; 5565 5566 for_each_class(class) { 5567 if (class->rq_offline) 5568 class->rq_offline(rq); 5569 } 5570 5571 cpumask_clear_cpu(rq->cpu, rq->rd->online); 5572 rq->online = 0; 5573 } 5574} 5575 5576/* 5577 * migration_call - callback that gets triggered when a CPU is added. 5578 * Here we can start up the necessary migration thread for the new CPU. 5579 */ 5580static int __cpuinit 5581migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) 5582{ 5583 int cpu = (long)hcpu; 5584 unsigned long flags; 5585 struct rq *rq = cpu_rq(cpu); 5586 5587 switch (action & ~CPU_TASKS_FROZEN) { 5588 5589 case CPU_UP_PREPARE: 5590 rq->calc_load_update = calc_load_update; 5591 break; 5592 5593 case CPU_ONLINE: 5594 /* Update our root-domain */ 5595 raw_spin_lock_irqsave(&rq->lock, flags); 5596 if (rq->rd) { 5597 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); 5598 5599 set_rq_online(rq); 5600 } 5601 raw_spin_unlock_irqrestore(&rq->lock, flags); 5602 break; 5603 5604#ifdef CONFIG_HOTPLUG_CPU 5605 case CPU_DYING: 5606 sched_ttwu_pending(); 5607 /* Update our root-domain */ 5608 raw_spin_lock_irqsave(&rq->lock, flags); 5609 if (rq->rd) { 5610 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); 5611 set_rq_offline(rq); 5612 } 5613 migrate_tasks(cpu); 5614 BUG_ON(rq->nr_running != 1); /* the migration thread */ 5615 raw_spin_unlock_irqrestore(&rq->lock, flags); 5616 5617 migrate_nr_uninterruptible(rq); 5618 calc_global_load_remove(rq); 5619 break; 5620#endif 5621 } 5622 5623 update_max_interval(); 5624 5625 return NOTIFY_OK; 5626} 5627 5628/* 5629 * Register at high priority so that task migration (migrate_all_tasks) 5630 * happens before everything else. This has to be lower priority than 5631 * the notifier in the perf_event subsystem, though. 5632 */ 5633static struct notifier_block __cpuinitdata migration_notifier = { 5634 .notifier_call = migration_call, 5635 .priority = CPU_PRI_MIGRATION, 5636}; 5637 5638static int __cpuinit sched_cpu_active(struct notifier_block *nfb, 5639 unsigned long action, void *hcpu) 5640{ 5641 switch (action & ~CPU_TASKS_FROZEN) { 5642 case CPU_STARTING: 5643 case CPU_DOWN_FAILED: 5644 set_cpu_active((long)hcpu, true); 5645 return NOTIFY_OK; 5646 default: 5647 return NOTIFY_DONE; 5648 } 5649} 5650 5651static int __cpuinit sched_cpu_inactive(struct notifier_block *nfb, 5652 unsigned long action, void *hcpu) 5653{ 5654 switch (action & ~CPU_TASKS_FROZEN) { 5655 case CPU_DOWN_PREPARE: 5656 set_cpu_active((long)hcpu, false); 5657 return NOTIFY_OK; 5658 default: 5659 return NOTIFY_DONE; 5660 } 5661} 5662 5663static int __init migration_init(void) 5664{ 5665 void *cpu = (void *)(long)smp_processor_id(); 5666 int err; 5667 5668 /* Initialize migration for the boot CPU */ 5669 err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); 5670 BUG_ON(err == NOTIFY_BAD); 5671 migration_call(&migration_notifier, CPU_ONLINE, cpu); 5672 register_cpu_notifier(&migration_notifier); 5673 5674 /* Register cpu active notifiers */ 5675 cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE); 5676 cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE); 5677 5678 return 0; 5679} 5680early_initcall(migration_init); 5681#endif 5682 5683#ifdef CONFIG_SMP 5684 5685static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */ 5686 5687#ifdef CONFIG_SCHED_DEBUG 5688 5689static __read_mostly int sched_debug_enabled; 5690 5691static int __init sched_debug_setup(char *str) 5692{ 5693 sched_debug_enabled = 1; 5694 5695 return 0; 5696} 5697early_param("sched_debug", sched_debug_setup); 5698 5699static inline bool sched_debug(void) 5700{ 5701 return sched_debug_enabled; 5702} 5703 5704static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, 5705 struct cpumask *groupmask) 5706{ 5707 struct sched_group *group = sd->groups; 5708 char str[256]; 5709 5710 cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd)); 5711 cpumask_clear(groupmask); 5712 5713 printk(KERN_DEBUG "%*s domain %d: ", level, "", level); 5714 5715 if (!(sd->flags & SD_LOAD_BALANCE)) { 5716 printk("does not load-balance\n"); 5717 if (sd->parent) 5718 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain" 5719 " has parent"); 5720 return -1; 5721 } 5722 5723 printk(KERN_CONT "span %s level %s\n", str, sd->name); 5724 5725 if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) { 5726 printk(KERN_ERR "ERROR: domain->span does not contain " 5727 "CPU%d\n", cpu); 5728 } 5729 if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) { 5730 printk(KERN_ERR "ERROR: domain->groups does not contain" 5731 " CPU%d\n", cpu); 5732 } 5733 5734 printk(KERN_DEBUG "%*s groups:", level + 1, ""); 5735 do { 5736 if (!group) { 5737 printk("\n"); 5738 printk(KERN_ERR "ERROR: group is NULL\n"); 5739 break; 5740 } 5741 5742 /* 5743 * Even though we initialize ->power to something semi-sane, 5744 * we leave power_orig unset. This allows us to detect if 5745 * domain iteration is still funny without causing /0 traps. 5746 */ 5747 if (!group->sgp->power_orig) { 5748 printk(KERN_CONT "\n"); 5749 printk(KERN_ERR "ERROR: domain->cpu_power not " 5750 "set\n"); 5751 break; 5752 } 5753 5754 if (!cpumask_weight(sched_group_cpus(group))) { 5755 printk(KERN_CONT "\n"); 5756 printk(KERN_ERR "ERROR: empty group\n"); 5757 break; 5758 } 5759 5760 if (!(sd->flags & SD_OVERLAP) && 5761 cpumask_intersects(groupmask, sched_group_cpus(group))) { 5762 printk(KERN_CONT "\n"); 5763 printk(KERN_ERR "ERROR: repeated CPUs\n"); 5764 break; 5765 } 5766 5767 cpumask_or(groupmask, groupmask, sched_group_cpus(group)); 5768 5769 cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group)); 5770 5771 printk(KERN_CONT " %s", str); 5772 if (group->sgp->power != SCHED_POWER_SCALE) { 5773 printk(KERN_CONT " (cpu_power = %d)", 5774 group->sgp->power); 5775 } 5776 5777 group = group->next; 5778 } while (group != sd->groups); 5779 printk(KERN_CONT "\n"); 5780 5781 if (!cpumask_equal(sched_domain_span(sd), groupmask)) 5782 printk(KERN_ERR "ERROR: groups don't span domain->span\n"); 5783 5784 if (sd->parent && 5785 !cpumask_subset(groupmask, sched_domain_span(sd->parent))) 5786 printk(KERN_ERR "ERROR: parent span is not a superset " 5787 "of domain->span\n"); 5788 return 0; 5789} 5790 5791static void sched_domain_debug(struct sched_domain *sd, int cpu) 5792{ 5793 int level = 0; 5794 5795 if (!sched_debug_enabled) 5796 return; 5797 5798 if (!sd) { 5799 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); 5800 return; 5801 } 5802 5803 printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); 5804 5805 for (;;) { 5806 if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask)) 5807 break; 5808 level++; 5809 sd = sd->parent; 5810 if (!sd) 5811 break; 5812 } 5813} 5814#else /* !CONFIG_SCHED_DEBUG */ 5815# define sched_domain_debug(sd, cpu) do { } while (0) 5816static inline bool sched_debug(void) 5817{ 5818 return false; 5819} 5820#endif /* CONFIG_SCHED_DEBUG */ 5821 5822static int sd_degenerate(struct sched_domain *sd) 5823{ 5824 if (cpumask_weight(sched_domain_span(sd)) == 1) 5825 return 1; 5826 5827 /* Following flags need at least 2 groups */ 5828 if (sd->flags & (SD_LOAD_BALANCE | 5829 SD_BALANCE_NEWIDLE | 5830 SD_BALANCE_FORK | 5831 SD_BALANCE_EXEC | 5832 SD_SHARE_CPUPOWER | 5833 SD_SHARE_PKG_RESOURCES)) { 5834 if (sd->groups != sd->groups->next) 5835 return 0; 5836 } 5837 5838 /* Following flags don't use groups */ 5839 if (sd->flags & (SD_WAKE_AFFINE)) 5840 return 0; 5841 5842 return 1; 5843} 5844 5845static int 5846sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) 5847{ 5848 unsigned long cflags = sd->flags, pflags = parent->flags; 5849 5850 if (sd_degenerate(parent)) 5851 return 1; 5852 5853 if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent))) 5854 return 0; 5855 5856 /* Flags needing groups don't count if only 1 group in parent */ 5857 if (parent->groups == parent->groups->next) { 5858 pflags &= ~(SD_LOAD_BALANCE | 5859 SD_BALANCE_NEWIDLE | 5860 SD_BALANCE_FORK | 5861 SD_BALANCE_EXEC | 5862 SD_SHARE_CPUPOWER | 5863 SD_SHARE_PKG_RESOURCES); 5864 if (nr_node_ids == 1) 5865 pflags &= ~SD_SERIALIZE; 5866 } 5867 if (~cflags & pflags) 5868 return 0; 5869 5870 return 1; 5871} 5872 5873static void free_rootdomain(struct rcu_head *rcu) 5874{ 5875 struct root_domain *rd = container_of(rcu, struct root_domain, rcu); 5876 5877 cpupri_cleanup(&rd->cpupri); 5878 free_cpumask_var(rd->rto_mask); 5879 free_cpumask_var(rd->online); 5880 free_cpumask_var(rd->span); 5881 kfree(rd); 5882} 5883 5884static void rq_attach_root(struct rq *rq, struct root_domain *rd) 5885{ 5886 struct root_domain *old_rd = NULL; 5887 unsigned long flags; 5888 5889 raw_spin_lock_irqsave(&rq->lock, flags); 5890 5891 if (rq->rd) { 5892 old_rd = rq->rd; 5893 5894 if (cpumask_test_cpu(rq->cpu, old_rd->online)) 5895 set_rq_offline(rq); 5896 5897 cpumask_clear_cpu(rq->cpu, old_rd->span); 5898 5899 /* 5900 * If we dont want to free the old_rt yet then 5901 * set old_rd to NULL to skip the freeing later 5902 * in this function: 5903 */ 5904 if (!atomic_dec_and_test(&old_rd->refcount)) 5905 old_rd = NULL; 5906 } 5907 5908 atomic_inc(&rd->refcount); 5909 rq->rd = rd; 5910 5911 cpumask_set_cpu(rq->cpu, rd->span); 5912 if (cpumask_test_cpu(rq->cpu, cpu_active_mask)) 5913 set_rq_online(rq); 5914 5915 raw_spin_unlock_irqrestore(&rq->lock, flags); 5916 5917 if (old_rd) 5918 call_rcu_sched(&old_rd->rcu, free_rootdomain); 5919} 5920 5921static int init_rootdomain(struct root_domain *rd) 5922{ 5923 memset(rd, 0, sizeof(*rd)); 5924 5925 if (!alloc_cpumask_var(&rd->span, GFP_KERNEL)) 5926 goto out; 5927 if (!alloc_cpumask_var(&rd->online, GFP_KERNEL)) 5928 goto free_span; 5929 if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL)) 5930 goto free_online; 5931 5932 if (cpupri_init(&rd->cpupri) != 0) 5933 goto free_rto_mask; 5934 return 0; 5935 5936free_rto_mask: 5937 free_cpumask_var(rd->rto_mask); 5938free_online: 5939 free_cpumask_var(rd->online); 5940free_span: 5941 free_cpumask_var(rd->span); 5942out: 5943 return -ENOMEM; 5944} 5945 5946/* 5947 * By default the system creates a single root-domain with all cpus as 5948 * members (mimicking the global state we have today). 5949 */ 5950struct root_domain def_root_domain; 5951 5952static void init_defrootdomain(void) 5953{ 5954 init_rootdomain(&def_root_domain); 5955 5956 atomic_set(&def_root_domain.refcount, 1); 5957} 5958 5959static struct root_domain *alloc_rootdomain(void) 5960{ 5961 struct root_domain *rd; 5962 5963 rd = kmalloc(sizeof(*rd), GFP_KERNEL); 5964 if (!rd) 5965 return NULL; 5966 5967 if (init_rootdomain(rd) != 0) { 5968 kfree(rd); 5969 return NULL; 5970 } 5971 5972 return rd; 5973} 5974 5975static void free_sched_groups(struct sched_group *sg, int free_sgp) 5976{ 5977 struct sched_group *tmp, *first; 5978 5979 if (!sg) 5980 return; 5981 5982 first = sg; 5983 do { 5984 tmp = sg->next; 5985 5986 if (free_sgp && atomic_dec_and_test(&sg->sgp->ref)) 5987 kfree(sg->sgp); 5988 5989 kfree(sg); 5990 sg = tmp; 5991 } while (sg != first); 5992} 5993 5994static void free_sched_domain(struct rcu_head *rcu) 5995{ 5996 struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu); 5997 5998 /* 5999 * If its an overlapping domain it has private groups, iterate and 6000 * nuke them all. 6001 */ 6002 if (sd->flags & SD_OVERLAP) { 6003 free_sched_groups(sd->groups, 1); 6004 } else if (atomic_dec_and_test(&sd->groups->ref)) { 6005 kfree(sd->groups->sgp); 6006 kfree(sd->groups); 6007 } 6008 kfree(sd); 6009} 6010 6011static void destroy_sched_domain(struct sched_domain *sd, int cpu) 6012{ 6013 call_rcu(&sd->rcu, free_sched_domain); 6014} 6015 6016static void destroy_sched_domains(struct sched_domain *sd, int cpu) 6017{ 6018 for (; sd; sd = sd->parent) 6019 destroy_sched_domain(sd, cpu); 6020} 6021 6022/* 6023 * Keep a special pointer to the highest sched_domain that has 6024 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this 6025 * allows us to avoid some pointer chasing select_idle_sibling(). 6026 * 6027 * Also keep a unique ID per domain (we use the first cpu number in 6028 * the cpumask of the domain), this allows us to quickly tell if 6029 * two cpus are in the same cache domain, see cpus_share_cache(). 6030 */ 6031DEFINE_PER_CPU(struct sched_domain *, sd_llc); 6032DEFINE_PER_CPU(int, sd_llc_id); 6033 6034static void update_top_cache_domain(int cpu) 6035{ 6036 struct sched_domain *sd; 6037 int id = cpu; 6038 6039 sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES); 6040 if (sd) 6041 id = cpumask_first(sched_domain_span(sd)); 6042 6043 rcu_assign_pointer(per_cpu(sd_llc, cpu), sd); 6044 per_cpu(sd_llc_id, cpu) = id; 6045} 6046 6047/* 6048 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must 6049 * hold the hotplug lock. 6050 */ 6051static void 6052cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) 6053{ 6054 struct rq *rq = cpu_rq(cpu); 6055 struct sched_domain *tmp; 6056 6057 /* Remove the sched domains which do not contribute to scheduling. */ 6058 for (tmp = sd; tmp; ) { 6059 struct sched_domain *parent = tmp->parent; 6060 if (!parent) 6061 break; 6062 6063 if (sd_parent_degenerate(tmp, parent)) { 6064 tmp->parent = parent->parent; 6065 if (parent->parent) 6066 parent->parent->child = tmp; 6067 destroy_sched_domain(parent, cpu); 6068 } else 6069 tmp = tmp->parent; 6070 } 6071 6072 if (sd && sd_degenerate(sd)) { 6073 tmp = sd; 6074 sd = sd->parent; 6075 destroy_sched_domain(tmp, cpu); 6076 if (sd) 6077 sd->child = NULL; 6078 } 6079 6080 sched_domain_debug(sd, cpu); 6081 6082 rq_attach_root(rq, rd); 6083 tmp = rq->sd; 6084 rcu_assign_pointer(rq->sd, sd); 6085 destroy_sched_domains(tmp, cpu); 6086 6087 update_top_cache_domain(cpu); 6088} 6089 6090/* cpus with isolated domains */ 6091static cpumask_var_t cpu_isolated_map; 6092 6093/* Setup the mask of cpus configured for isolated domains */ 6094static int __init isolated_cpu_setup(char *str) 6095{ 6096 alloc_bootmem_cpumask_var(&cpu_isolated_map); 6097 cpulist_parse(str, cpu_isolated_map); 6098 return 1; 6099} 6100 6101__setup("isolcpus=", isolated_cpu_setup); 6102 6103static const struct cpumask *cpu_cpu_mask(int cpu) 6104{ 6105 return cpumask_of_node(cpu_to_node(cpu)); 6106} 6107 6108struct sd_data { 6109 struct sched_domain **__percpu sd; 6110 struct sched_group **__percpu sg; 6111 struct sched_group_power **__percpu sgp; 6112}; 6113 6114struct s_data { 6115 struct sched_domain ** __percpu sd; 6116 struct root_domain *rd; 6117}; 6118 6119enum s_alloc { 6120 sa_rootdomain, 6121 sa_sd, 6122 sa_sd_storage, 6123 sa_none, 6124}; 6125 6126struct sched_domain_topology_level; 6127 6128typedef struct sched_domain *(*sched_domain_init_f)(struct sched_domain_topology_level *tl, int cpu); 6129typedef const struct cpumask *(*sched_domain_mask_f)(int cpu); 6130 6131#define SDTL_OVERLAP 0x01 6132 6133struct sched_domain_topology_level { 6134 sched_domain_init_f init; 6135 sched_domain_mask_f mask; 6136 int flags; 6137 int numa_level; 6138 struct sd_data data; 6139}; 6140 6141/* 6142 * Build an iteration mask that can exclude certain CPUs from the upwards 6143 * domain traversal. 6144 * 6145 * Asymmetric node setups can result in situations where the domain tree is of 6146 * unequal depth, make sure to skip domains that already cover the entire 6147 * range. 6148 * 6149 * In that case build_sched_domains() will have terminated the iteration early 6150 * and our sibling sd spans will be empty. Domains should always include the 6151 * cpu they're built on, so check that. 6152 * 6153 */ 6154static void build_group_mask(struct sched_domain *sd, struct sched_group *sg) 6155{ 6156 const struct cpumask *span = sched_domain_span(sd); 6157 struct sd_data *sdd = sd->private; 6158 struct sched_domain *sibling; 6159 int i; 6160 6161 for_each_cpu(i, span) { 6162 sibling = *per_cpu_ptr(sdd->sd, i); 6163 if (!cpumask_test_cpu(i, sched_domain_span(sibling))) 6164 continue; 6165 6166 cpumask_set_cpu(i, sched_group_mask(sg)); 6167 } 6168} 6169 6170/* 6171 * Return the canonical balance cpu for this group, this is the first cpu 6172 * of this group that's also in the iteration mask. 6173 */ 6174int group_balance_cpu(struct sched_group *sg) 6175{ 6176 return cpumask_first_and(sched_group_cpus(sg), sched_group_mask(sg)); 6177} 6178 6179static int 6180build_overlap_sched_groups(struct sched_domain *sd, int cpu) 6181{ 6182 struct sched_group *first = NULL, *last = NULL, *groups = NULL, *sg; 6183 const struct cpumask *span = sched_domain_span(sd); 6184 struct cpumask *covered = sched_domains_tmpmask; 6185 struct sd_data *sdd = sd->private; 6186 struct sched_domain *child; 6187 int i; 6188 6189 cpumask_clear(covered); 6190 6191 for_each_cpu(i, span) { 6192 struct cpumask *sg_span; 6193 6194 if (cpumask_test_cpu(i, covered)) 6195 continue; 6196 6197 child = *per_cpu_ptr(sdd->sd, i); 6198 6199 /* See the comment near build_group_mask(). */ 6200 if (!cpumask_test_cpu(i, sched_domain_span(child))) 6201 continue; 6202 6203 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), 6204 GFP_KERNEL, cpu_to_node(cpu)); 6205 6206 if (!sg) 6207 goto fail; 6208 6209 sg_span = sched_group_cpus(sg); 6210 if (child->child) { 6211 child = child->child; 6212 cpumask_copy(sg_span, sched_domain_span(child)); 6213 } else 6214 cpumask_set_cpu(i, sg_span); 6215 6216 cpumask_or(covered, covered, sg_span); 6217 6218 sg->sgp = *per_cpu_ptr(sdd->sgp, i); 6219 if (atomic_inc_return(&sg->sgp->ref) == 1) 6220 build_group_mask(sd, sg); 6221 6222 /* 6223 * Initialize sgp->power such that even if we mess up the 6224 * domains and no possible iteration will get us here, we won't 6225 * die on a /0 trap. 6226 */ 6227 sg->sgp->power = SCHED_POWER_SCALE * cpumask_weight(sg_span); 6228 6229 /* 6230 * Make sure the first group of this domain contains the 6231 * canonical balance cpu. Otherwise the sched_domain iteration 6232 * breaks. See update_sg_lb_stats(). 6233 */ 6234 if ((!groups && cpumask_test_cpu(cpu, sg_span)) || 6235 group_balance_cpu(sg) == cpu) 6236 groups = sg; 6237 6238 if (!first) 6239 first = sg; 6240 if (last) 6241 last->next = sg; 6242 last = sg; 6243 last->next = first; 6244 } 6245 sd->groups = groups; 6246 6247 return 0; 6248 6249fail: 6250 free_sched_groups(first, 0); 6251 6252 return -ENOMEM; 6253} 6254 6255static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg) 6256{ 6257 struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu); 6258 struct sched_domain *child = sd->child; 6259 6260 if (child) 6261 cpu = cpumask_first(sched_domain_span(child)); 6262 6263 if (sg) { 6264 *sg = *per_cpu_ptr(sdd->sg, cpu); 6265 (*sg)->sgp = *per_cpu_ptr(sdd->sgp, cpu); 6266 atomic_set(&(*sg)->sgp->ref, 1); /* for claim_allocations */ 6267 } 6268 6269 return cpu; 6270} 6271 6272/* 6273 * build_sched_groups will build a circular linked list of the groups 6274 * covered by the given span, and will set each group's ->cpumask correctly, 6275 * and ->cpu_power to 0. 6276 * 6277 * Assumes the sched_domain tree is fully constructed 6278 */ 6279static int 6280build_sched_groups(struct sched_domain *sd, int cpu) 6281{ 6282 struct sched_group *first = NULL, *last = NULL; 6283 struct sd_data *sdd = sd->private; 6284 const struct cpumask *span = sched_domain_span(sd); 6285 struct cpumask *covered; 6286 int i; 6287 6288 get_group(cpu, sdd, &sd->groups); 6289 atomic_inc(&sd->groups->ref); 6290 6291 if (cpu != cpumask_first(sched_domain_span(sd))) 6292 return 0; 6293 6294 lockdep_assert_held(&sched_domains_mutex); 6295 covered = sched_domains_tmpmask; 6296 6297 cpumask_clear(covered); 6298 6299 for_each_cpu(i, span) { 6300 struct sched_group *sg; 6301 int group = get_group(i, sdd, &sg); 6302 int j; 6303 6304 if (cpumask_test_cpu(i, covered)) 6305 continue; 6306 6307 cpumask_clear(sched_group_cpus(sg)); 6308 sg->sgp->power = 0; 6309 cpumask_setall(sched_group_mask(sg)); 6310 6311 for_each_cpu(j, span) { 6312 if (get_group(j, sdd, NULL) != group) 6313 continue; 6314 6315 cpumask_set_cpu(j, covered); 6316 cpumask_set_cpu(j, sched_group_cpus(sg)); 6317 } 6318 6319 if (!first) 6320 first = sg; 6321 if (last) 6322 last->next = sg; 6323 last = sg; 6324 } 6325 last->next = first; 6326 6327 return 0; 6328} 6329 6330/* 6331 * Initialize sched groups cpu_power. 6332 * 6333 * cpu_power indicates the capacity of sched group, which is used while 6334 * distributing the load between different sched groups in a sched domain. 6335 * Typically cpu_power for all the groups in a sched domain will be same unless 6336 * there are asymmetries in the topology. If there are asymmetries, group 6337 * having more cpu_power will pickup more load compared to the group having 6338 * less cpu_power. 6339 */ 6340static void init_sched_groups_power(int cpu, struct sched_domain *sd) 6341{ 6342 struct sched_group *sg = sd->groups; 6343 6344 WARN_ON(!sd || !sg); 6345 6346 do { 6347 sg->group_weight = cpumask_weight(sched_group_cpus(sg)); 6348 sg = sg->next; 6349 } while (sg != sd->groups); 6350 6351 if (cpu != group_balance_cpu(sg)) 6352 return; 6353 6354 update_group_power(sd, cpu); 6355 atomic_set(&sg->sgp->nr_busy_cpus, sg->group_weight); 6356} 6357 6358int __weak arch_sd_sibling_asym_packing(void) 6359{ 6360 return 0*SD_ASYM_PACKING; 6361} 6362 6363/* 6364 * Initializers for schedule domains 6365 * Non-inlined to reduce accumulated stack pressure in build_sched_domains() 6366 */ 6367 6368#ifdef CONFIG_SCHED_DEBUG 6369# define SD_INIT_NAME(sd, type) sd->name = #type 6370#else 6371# define SD_INIT_NAME(sd, type) do { } while (0) 6372#endif 6373 6374#define SD_INIT_FUNC(type) \ 6375static noinline struct sched_domain * \ 6376sd_init_##type(struct sched_domain_topology_level *tl, int cpu) \ 6377{ \ 6378 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); \ 6379 *sd = SD_##type##_INIT; \ 6380 SD_INIT_NAME(sd, type); \ 6381 sd->private = &tl->data; \ 6382 return sd; \ 6383} 6384 6385SD_INIT_FUNC(CPU) 6386#ifdef CONFIG_SCHED_SMT 6387 SD_INIT_FUNC(SIBLING) 6388#endif 6389#ifdef CONFIG_SCHED_MC 6390 SD_INIT_FUNC(MC) 6391#endif 6392#ifdef CONFIG_SCHED_BOOK 6393 SD_INIT_FUNC(BOOK) 6394#endif 6395 6396static int default_relax_domain_level = -1; 6397int sched_domain_level_max; 6398 6399static int __init setup_relax_domain_level(char *str) 6400{ 6401 if (kstrtoint(str, 0, &default_relax_domain_level)) 6402 pr_warn("Unable to set relax_domain_level\n"); 6403 6404 return 1; 6405} 6406__setup("relax_domain_level=", setup_relax_domain_level); 6407 6408static void set_domain_attribute(struct sched_domain *sd, 6409 struct sched_domain_attr *attr) 6410{ 6411 int request; 6412 6413 if (!attr || attr->relax_domain_level < 0) { 6414 if (default_relax_domain_level < 0) 6415 return; 6416 else 6417 request = default_relax_domain_level; 6418 } else 6419 request = attr->relax_domain_level; 6420 if (request < sd->level) { 6421 /* turn off idle balance on this domain */ 6422 sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); 6423 } else { 6424 /* turn on idle balance on this domain */ 6425 sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); 6426 } 6427} 6428 6429static void __sdt_free(const struct cpumask *cpu_map); 6430static int __sdt_alloc(const struct cpumask *cpu_map); 6431 6432static void __free_domain_allocs(struct s_data *d, enum s_alloc what, 6433 const struct cpumask *cpu_map) 6434{ 6435 switch (what) { 6436 case sa_rootdomain: 6437 if (!atomic_read(&d->rd->refcount)) 6438 free_rootdomain(&d->rd->rcu); /* fall through */ 6439 case sa_sd: 6440 free_percpu(d->sd); /* fall through */ 6441 case sa_sd_storage: 6442 __sdt_free(cpu_map); /* fall through */ 6443 case sa_none: 6444 break; 6445 } 6446} 6447 6448static enum s_alloc __visit_domain_allocation_hell(struct s_data *d, 6449 const struct cpumask *cpu_map) 6450{ 6451 memset(d, 0, sizeof(*d)); 6452 6453 if (__sdt_alloc(cpu_map)) 6454 return sa_sd_storage; 6455 d->sd = alloc_percpu(struct sched_domain *); 6456 if (!d->sd) 6457 return sa_sd_storage; 6458 d->rd = alloc_rootdomain(); 6459 if (!d->rd) 6460 return sa_sd; 6461 return sa_rootdomain; 6462} 6463 6464/* 6465 * NULL the sd_data elements we've used to build the sched_domain and 6466 * sched_group structure so that the subsequent __free_domain_allocs() 6467 * will not free the data we're using. 6468 */ 6469static void claim_allocations(int cpu, struct sched_domain *sd) 6470{ 6471 struct sd_data *sdd = sd->private; 6472 6473 WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd); 6474 *per_cpu_ptr(sdd->sd, cpu) = NULL; 6475 6476 if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref)) 6477 *per_cpu_ptr(sdd->sg, cpu) = NULL; 6478 6479 if (atomic_read(&(*per_cpu_ptr(sdd->sgp, cpu))->ref)) 6480 *per_cpu_ptr(sdd->sgp, cpu) = NULL; 6481} 6482 6483#ifdef CONFIG_SCHED_SMT 6484static const struct cpumask *cpu_smt_mask(int cpu) 6485{ 6486 return topology_thread_cpumask(cpu); 6487} 6488#endif 6489 6490/* 6491 * Topology list, bottom-up. 6492 */ 6493static struct sched_domain_topology_level default_topology[] = { 6494#ifdef CONFIG_SCHED_SMT 6495 { sd_init_SIBLING, cpu_smt_mask, }, 6496#endif 6497#ifdef CONFIG_SCHED_MC 6498 { sd_init_MC, cpu_coregroup_mask, }, 6499#endif 6500#ifdef CONFIG_SCHED_BOOK 6501 { sd_init_BOOK, cpu_book_mask, }, 6502#endif 6503 { sd_init_CPU, cpu_cpu_mask, }, 6504 { NULL, }, 6505}; 6506 6507static struct sched_domain_topology_level *sched_domain_topology = default_topology; 6508 6509#ifdef CONFIG_NUMA 6510 6511static int sched_domains_numa_levels; 6512static int *sched_domains_numa_distance; 6513static struct cpumask ***sched_domains_numa_masks; 6514static int sched_domains_curr_level; 6515 6516static inline int sd_local_flags(int level) 6517{ 6518 if (sched_domains_numa_distance[level] > RECLAIM_DISTANCE) 6519 return 0; 6520 6521 return SD_BALANCE_EXEC | SD_BALANCE_FORK | SD_WAKE_AFFINE; 6522} 6523 6524static struct sched_domain * 6525sd_numa_init(struct sched_domain_topology_level *tl, int cpu) 6526{ 6527 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); 6528 int level = tl->numa_level; 6529 int sd_weight = cpumask_weight( 6530 sched_domains_numa_masks[level][cpu_to_node(cpu)]); 6531 6532 *sd = (struct sched_domain){ 6533 .min_interval = sd_weight, 6534 .max_interval = 2*sd_weight, 6535 .busy_factor = 32, 6536 .imbalance_pct = 125, 6537 .cache_nice_tries = 2, 6538 .busy_idx = 3, 6539 .idle_idx = 2, 6540 .newidle_idx = 0, 6541 .wake_idx = 0, 6542 .forkexec_idx = 0, 6543 6544 .flags = 1*SD_LOAD_BALANCE 6545 | 1*SD_BALANCE_NEWIDLE 6546 | 0*SD_BALANCE_EXEC 6547 | 0*SD_BALANCE_FORK 6548 | 0*SD_BALANCE_WAKE 6549 | 0*SD_WAKE_AFFINE 6550 | 0*SD_PREFER_LOCAL 6551 | 0*SD_SHARE_CPUPOWER 6552 | 0*SD_SHARE_PKG_RESOURCES 6553 | 1*SD_SERIALIZE 6554 | 0*SD_PREFER_SIBLING 6555 | sd_local_flags(level) 6556 , 6557 .last_balance = jiffies, 6558 .balance_interval = sd_weight, 6559 }; 6560 SD_INIT_NAME(sd, NUMA); 6561 sd->private = &tl->data; 6562 6563 /* 6564 * Ugly hack to pass state to sd_numa_mask()... 6565 */ 6566 sched_domains_curr_level = tl->numa_level; 6567 6568 return sd; 6569} 6570 6571static const struct cpumask *sd_numa_mask(int cpu) 6572{ 6573 return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)]; 6574} 6575 6576static void sched_numa_warn(const char *str) 6577{ 6578 static int done = false; 6579 int i,j; 6580 6581 if (done) 6582 return; 6583 6584 done = true; 6585 6586 printk(KERN_WARNING "ERROR: %s\n\n", str); 6587 6588 for (i = 0; i < nr_node_ids; i++) { 6589 printk(KERN_WARNING " "); 6590 for (j = 0; j < nr_node_ids; j++) 6591 printk(KERN_CONT "%02d ", node_distance(i,j)); 6592 printk(KERN_CONT "\n"); 6593 } 6594 printk(KERN_WARNING "\n"); 6595} 6596 6597static bool find_numa_distance(int distance) 6598{ 6599 int i; 6600 6601 if (distance == node_distance(0, 0)) 6602 return true; 6603 6604 for (i = 0; i < sched_domains_numa_levels; i++) { 6605 if (sched_domains_numa_distance[i] == distance) 6606 return true; 6607 } 6608 6609 return false; 6610} 6611 6612static void sched_init_numa(void) 6613{ 6614 int next_distance, curr_distance = node_distance(0, 0); 6615 struct sched_domain_topology_level *tl; 6616 int level = 0; 6617 int i, j, k; 6618 6619 sched_domains_numa_distance = kzalloc(sizeof(int) * nr_node_ids, GFP_KERNEL); 6620 if (!sched_domains_numa_distance) 6621 return; 6622 6623 /* 6624 * O(nr_nodes^2) deduplicating selection sort -- in order to find the 6625 * unique distances in the node_distance() table. 6626 * 6627 * Assumes node_distance(0,j) includes all distances in 6628 * node_distance(i,j) in order to avoid cubic time. 6629 */ 6630 next_distance = curr_distance; 6631 for (i = 0; i < nr_node_ids; i++) { 6632 for (j = 0; j < nr_node_ids; j++) { 6633 for (k = 0; k < nr_node_ids; k++) { 6634 int distance = node_distance(i, k); 6635 6636 if (distance > curr_distance && 6637 (distance < next_distance || 6638 next_distance == curr_distance)) 6639 next_distance = distance; 6640 6641 /* 6642 * While not a strong assumption it would be nice to know 6643 * about cases where if node A is connected to B, B is not 6644 * equally connected to A. 6645 */ 6646 if (sched_debug() && node_distance(k, i) != distance) 6647 sched_numa_warn("Node-distance not symmetric"); 6648 6649 if (sched_debug() && i && !find_numa_distance(distance)) 6650 sched_numa_warn("Node-0 not representative"); 6651 } 6652 if (next_distance != curr_distance) { 6653 sched_domains_numa_distance[level++] = next_distance; 6654 sched_domains_numa_levels = level; 6655 curr_distance = next_distance; 6656 } else break; 6657 } 6658 6659 /* 6660 * In case of sched_debug() we verify the above assumption. 6661 */ 6662 if (!sched_debug()) 6663 break; 6664 } 6665 /* 6666 * 'level' contains the number of unique distances, excluding the 6667 * identity distance node_distance(i,i). 6668 * 6669 * The sched_domains_nume_distance[] array includes the actual distance 6670 * numbers. 6671 */ 6672 6673 sched_domains_numa_masks = kzalloc(sizeof(void *) * level, GFP_KERNEL); 6674 if (!sched_domains_numa_masks) 6675 return; 6676 6677 /* 6678 * Now for each level, construct a mask per node which contains all 6679 * cpus of nodes that are that many hops away from us. 6680 */ 6681 for (i = 0; i < level; i++) { 6682 sched_domains_numa_masks[i] = 6683 kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL); 6684 if (!sched_domains_numa_masks[i]) 6685 return; 6686 6687 for (j = 0; j < nr_node_ids; j++) { 6688 struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL); 6689 if (!mask) 6690 return; 6691 6692 sched_domains_numa_masks[i][j] = mask; 6693 6694 for (k = 0; k < nr_node_ids; k++) { 6695 if (node_distance(j, k) > sched_domains_numa_distance[i]) 6696 continue; 6697 6698 cpumask_or(mask, mask, cpumask_of_node(k)); 6699 } 6700 } 6701 } 6702 6703 tl = kzalloc((ARRAY_SIZE(default_topology) + level) * 6704 sizeof(struct sched_domain_topology_level), GFP_KERNEL); 6705 if (!tl) 6706 return; 6707 6708 /* 6709 * Copy the default topology bits.. 6710 */ 6711 for (i = 0; default_topology[i].init; i++) 6712 tl[i] = default_topology[i]; 6713 6714 /* 6715 * .. and append 'j' levels of NUMA goodness. 6716 */ 6717 for (j = 0; j < level; i++, j++) { 6718 tl[i] = (struct sched_domain_topology_level){ 6719 .init = sd_numa_init, 6720 .mask = sd_numa_mask, 6721 .flags = SDTL_OVERLAP, 6722 .numa_level = j, 6723 }; 6724 } 6725 6726 sched_domain_topology = tl; 6727} 6728#else 6729static inline void sched_init_numa(void) 6730{ 6731} 6732#endif /* CONFIG_NUMA */ 6733 6734static int __sdt_alloc(const struct cpumask *cpu_map) 6735{ 6736 struct sched_domain_topology_level *tl; 6737 int j; 6738 6739 for (tl = sched_domain_topology; tl->init; tl++) { 6740 struct sd_data *sdd = &tl->data; 6741 6742 sdd->sd = alloc_percpu(struct sched_domain *); 6743 if (!sdd->sd) 6744 return -ENOMEM; 6745 6746 sdd->sg = alloc_percpu(struct sched_group *); 6747 if (!sdd->sg) 6748 return -ENOMEM; 6749 6750 sdd->sgp = alloc_percpu(struct sched_group_power *); 6751 if (!sdd->sgp) 6752 return -ENOMEM; 6753 6754 for_each_cpu(j, cpu_map) { 6755 struct sched_domain *sd; 6756 struct sched_group *sg; 6757 struct sched_group_power *sgp; 6758 6759 sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(), 6760 GFP_KERNEL, cpu_to_node(j)); 6761 if (!sd) 6762 return -ENOMEM; 6763 6764 *per_cpu_ptr(sdd->sd, j) = sd; 6765 6766 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), 6767 GFP_KERNEL, cpu_to_node(j)); 6768 if (!sg) 6769 return -ENOMEM; 6770 6771 sg->next = sg; 6772 6773 *per_cpu_ptr(sdd->sg, j) = sg; 6774 6775 sgp = kzalloc_node(sizeof(struct sched_group_power) + cpumask_size(), 6776 GFP_KERNEL, cpu_to_node(j)); 6777 if (!sgp) 6778 return -ENOMEM; 6779 6780 *per_cpu_ptr(sdd->sgp, j) = sgp; 6781 } 6782 } 6783 6784 return 0; 6785} 6786 6787static void __sdt_free(const struct cpumask *cpu_map) 6788{ 6789 struct sched_domain_topology_level *tl; 6790 int j; 6791 6792 for (tl = sched_domain_topology; tl->init; tl++) { 6793 struct sd_data *sdd = &tl->data; 6794 6795 for_each_cpu(j, cpu_map) { 6796 struct sched_domain *sd; 6797 6798 if (sdd->sd) { 6799 sd = *per_cpu_ptr(sdd->sd, j); 6800 if (sd && (sd->flags & SD_OVERLAP)) 6801 free_sched_groups(sd->groups, 0); 6802 kfree(*per_cpu_ptr(sdd->sd, j)); 6803 } 6804 6805 if (sdd->sg) 6806 kfree(*per_cpu_ptr(sdd->sg, j)); 6807 if (sdd->sgp) 6808 kfree(*per_cpu_ptr(sdd->sgp, j)); 6809 } 6810 free_percpu(sdd->sd); 6811 sdd->sd = NULL; 6812 free_percpu(sdd->sg); 6813 sdd->sg = NULL; 6814 free_percpu(sdd->sgp); 6815 sdd->sgp = NULL; 6816 } 6817} 6818 6819struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl, 6820 struct s_data *d, const struct cpumask *cpu_map, 6821 struct sched_domain_attr *attr, struct sched_domain *child, 6822 int cpu) 6823{ 6824 struct sched_domain *sd = tl->init(tl, cpu); 6825 if (!sd) 6826 return child; 6827 6828 cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu)); 6829 if (child) { 6830 sd->level = child->level + 1; 6831 sched_domain_level_max = max(sched_domain_level_max, sd->level); 6832 child->parent = sd; 6833 } 6834 sd->child = child; 6835 set_domain_attribute(sd, attr); 6836 6837 return sd; 6838} 6839 6840/* 6841 * Build sched domains for a given set of cpus and attach the sched domains 6842 * to the individual cpus 6843 */ 6844static int build_sched_domains(const struct cpumask *cpu_map, 6845 struct sched_domain_attr *attr) 6846{ 6847 enum s_alloc alloc_state = sa_none; 6848 struct sched_domain *sd; 6849 struct s_data d; 6850 int i, ret = -ENOMEM; 6851 6852 alloc_state = __visit_domain_allocation_hell(&d, cpu_map); 6853 if (alloc_state != sa_rootdomain) 6854 goto error; 6855 6856 /* Set up domains for cpus specified by the cpu_map. */ 6857 for_each_cpu(i, cpu_map) { 6858 struct sched_domain_topology_level *tl; 6859 6860 sd = NULL; 6861 for (tl = sched_domain_topology; tl->init; tl++) { 6862 sd = build_sched_domain(tl, &d, cpu_map, attr, sd, i); 6863 if (tl->flags & SDTL_OVERLAP || sched_feat(FORCE_SD_OVERLAP)) 6864 sd->flags |= SD_OVERLAP; 6865 if (cpumask_equal(cpu_map, sched_domain_span(sd))) 6866 break; 6867 } 6868 6869 while (sd->child) 6870 sd = sd->child; 6871 6872 *per_cpu_ptr(d.sd, i) = sd; 6873 } 6874 6875 /* Build the groups for the domains */ 6876 for_each_cpu(i, cpu_map) { 6877 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { 6878 sd->span_weight = cpumask_weight(sched_domain_span(sd)); 6879 if (sd->flags & SD_OVERLAP) { 6880 if (build_overlap_sched_groups(sd, i)) 6881 goto error; 6882 } else { 6883 if (build_sched_groups(sd, i)) 6884 goto error; 6885 } 6886 } 6887 } 6888 6889 /* Calculate CPU power for physical packages and nodes */ 6890 for (i = nr_cpumask_bits-1; i >= 0; i--) { 6891 if (!cpumask_test_cpu(i, cpu_map)) 6892 continue; 6893 6894 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { 6895 claim_allocations(i, sd); 6896 init_sched_groups_power(i, sd); 6897 } 6898 } 6899 6900 /* Attach the domains */ 6901 rcu_read_lock(); 6902 for_each_cpu(i, cpu_map) { 6903 sd = *per_cpu_ptr(d.sd, i); 6904 cpu_attach_domain(sd, d.rd, i); 6905 } 6906 rcu_read_unlock(); 6907 6908 ret = 0; 6909error: 6910 __free_domain_allocs(&d, alloc_state, cpu_map); 6911 return ret; 6912} 6913 6914static cpumask_var_t *doms_cur; /* current sched domains */ 6915static int ndoms_cur; /* number of sched domains in 'doms_cur' */ 6916static struct sched_domain_attr *dattr_cur; 6917 /* attribues of custom domains in 'doms_cur' */ 6918 6919/* 6920 * Special case: If a kmalloc of a doms_cur partition (array of 6921 * cpumask) fails, then fallback to a single sched domain, 6922 * as determined by the single cpumask fallback_doms. 6923 */ 6924static cpumask_var_t fallback_doms; 6925 6926/* 6927 * arch_update_cpu_topology lets virtualized architectures update the 6928 * cpu core maps. It is supposed to return 1 if the topology changed 6929 * or 0 if it stayed the same. 6930 */ 6931int __attribute__((weak)) arch_update_cpu_topology(void) 6932{ 6933 return 0; 6934} 6935 6936cpumask_var_t *alloc_sched_domains(unsigned int ndoms) 6937{ 6938 int i; 6939 cpumask_var_t *doms; 6940 6941 doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL); 6942 if (!doms) 6943 return NULL; 6944 for (i = 0; i < ndoms; i++) { 6945 if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) { 6946 free_sched_domains(doms, i); 6947 return NULL; 6948 } 6949 } 6950 return doms; 6951} 6952 6953void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms) 6954{ 6955 unsigned int i; 6956 for (i = 0; i < ndoms; i++) 6957 free_cpumask_var(doms[i]); 6958 kfree(doms); 6959} 6960 6961/* 6962 * Set up scheduler domains and groups. Callers must hold the hotplug lock. 6963 * For now this just excludes isolated cpus, but could be used to 6964 * exclude other special cases in the future. 6965 */ 6966static int init_sched_domains(const struct cpumask *cpu_map) 6967{ 6968 int err; 6969 6970 arch_update_cpu_topology(); 6971 ndoms_cur = 1; 6972 doms_cur = alloc_sched_domains(ndoms_cur); 6973 if (!doms_cur) 6974 doms_cur = &fallback_doms; 6975 cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map); 6976 err = build_sched_domains(doms_cur[0], NULL); 6977 register_sched_domain_sysctl(); 6978 6979 return err; 6980} 6981 6982/* 6983 * Detach sched domains from a group of cpus specified in cpu_map 6984 * These cpus will now be attached to the NULL domain 6985 */ 6986static void detach_destroy_domains(const struct cpumask *cpu_map) 6987{ 6988 int i; 6989 6990 rcu_read_lock(); 6991 for_each_cpu(i, cpu_map) 6992 cpu_attach_domain(NULL, &def_root_domain, i); 6993 rcu_read_unlock(); 6994} 6995 6996/* handle null as "default" */ 6997static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur, 6998 struct sched_domain_attr *new, int idx_new) 6999{ 7000 struct sched_domain_attr tmp; 7001 7002 /* fast path */ 7003 if (!new && !cur) 7004 return 1; 7005 7006 tmp = SD_ATTR_INIT; 7007 return !memcmp(cur ? (cur + idx_cur) : &tmp, 7008 new ? (new + idx_new) : &tmp, 7009 sizeof(struct sched_domain_attr)); 7010} 7011 7012/* 7013 * Partition sched domains as specified by the 'ndoms_new' 7014 * cpumasks in the array doms_new[] of cpumasks. This compares 7015 * doms_new[] to the current sched domain partitioning, doms_cur[]. 7016 * It destroys each deleted domain and builds each new domain. 7017 * 7018 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'. 7019 * The masks don't intersect (don't overlap.) We should setup one 7020 * sched domain for each mask. CPUs not in any of the cpumasks will 7021 * not be load balanced. If the same cpumask appears both in the 7022 * current 'doms_cur' domains and in the new 'doms_new', we can leave 7023 * it as it is. 7024 * 7025 * The passed in 'doms_new' should be allocated using 7026 * alloc_sched_domains. This routine takes ownership of it and will 7027 * free_sched_domains it when done with it. If the caller failed the 7028 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1, 7029 * and partition_sched_domains() will fallback to the single partition 7030 * 'fallback_doms', it also forces the domains to be rebuilt. 7031 * 7032 * If doms_new == NULL it will be replaced with cpu_online_mask. 7033 * ndoms_new == 0 is a special case for destroying existing domains, 7034 * and it will not create the default domain. 7035 * 7036 * Call with hotplug lock held 7037 */ 7038void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[], 7039 struct sched_domain_attr *dattr_new) 7040{ 7041 int i, j, n; 7042 int new_topology; 7043 7044 mutex_lock(&sched_domains_mutex); 7045 7046 /* always unregister in case we don't destroy any domains */ 7047 unregister_sched_domain_sysctl(); 7048 7049 /* Let architecture update cpu core mappings. */ 7050 new_topology = arch_update_cpu_topology(); 7051 7052 n = doms_new ? ndoms_new : 0; 7053 7054 /* Destroy deleted domains */ 7055 for (i = 0; i < ndoms_cur; i++) { 7056 for (j = 0; j < n && !new_topology; j++) { 7057 if (cpumask_equal(doms_cur[i], doms_new[j]) 7058 && dattrs_equal(dattr_cur, i, dattr_new, j)) 7059 goto match1; 7060 } 7061 /* no match - a current sched domain not in new doms_new[] */ 7062 detach_destroy_domains(doms_cur[i]); 7063match1: 7064 ; 7065 } 7066 7067 if (doms_new == NULL) { 7068 ndoms_cur = 0; 7069 doms_new = &fallback_doms; 7070 cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map); 7071 WARN_ON_ONCE(dattr_new); 7072 } 7073 7074 /* Build new domains */ 7075 for (i = 0; i < ndoms_new; i++) { 7076 for (j = 0; j < ndoms_cur && !new_topology; j++) { 7077 if (cpumask_equal(doms_new[i], doms_cur[j]) 7078 && dattrs_equal(dattr_new, i, dattr_cur, j)) 7079 goto match2; 7080 } 7081 /* no match - add a new doms_new */ 7082 build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL); 7083match2: 7084 ; 7085 } 7086 7087 /* Remember the new sched domains */ 7088 if (doms_cur != &fallback_doms) 7089 free_sched_domains(doms_cur, ndoms_cur); 7090 kfree(dattr_cur); /* kfree(NULL) is safe */ 7091 doms_cur = doms_new; 7092 dattr_cur = dattr_new; 7093 ndoms_cur = ndoms_new; 7094 7095 register_sched_domain_sysctl(); 7096 7097 mutex_unlock(&sched_domains_mutex); 7098} 7099 7100/* 7101 * Update cpusets according to cpu_active mask. If cpusets are 7102 * disabled, cpuset_update_active_cpus() becomes a simple wrapper 7103 * around partition_sched_domains(). 7104 */ 7105static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action, 7106 void *hcpu) 7107{ 7108 switch (action & ~CPU_TASKS_FROZEN) { 7109 case CPU_ONLINE: 7110 case CPU_DOWN_FAILED: 7111 cpuset_update_active_cpus(); 7112 return NOTIFY_OK; 7113 default: 7114 return NOTIFY_DONE; 7115 } 7116} 7117 7118static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action, 7119 void *hcpu) 7120{ 7121 switch (action & ~CPU_TASKS_FROZEN) { 7122 case CPU_DOWN_PREPARE: 7123 cpuset_update_active_cpus(); 7124 return NOTIFY_OK; 7125 default: 7126 return NOTIFY_DONE; 7127 } 7128} 7129 7130void __init sched_init_smp(void) 7131{ 7132 cpumask_var_t non_isolated_cpus; 7133 7134 alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL); 7135 alloc_cpumask_var(&fallback_doms, GFP_KERNEL); 7136 7137 sched_init_numa(); 7138 7139 get_online_cpus(); 7140 mutex_lock(&sched_domains_mutex); 7141 init_sched_domains(cpu_active_mask); 7142 cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map); 7143 if (cpumask_empty(non_isolated_cpus)) 7144 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus); 7145 mutex_unlock(&sched_domains_mutex); 7146 put_online_cpus(); 7147 7148 hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE); 7149 hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE); 7150 7151 /* RT runtime code needs to handle some hotplug events */ 7152 hotcpu_notifier(update_runtime, 0); 7153 7154 init_hrtick(); 7155 7156 /* Move init over to a non-isolated CPU */ 7157 if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0) 7158 BUG(); 7159 sched_init_granularity(); 7160 free_cpumask_var(non_isolated_cpus); 7161 7162 init_sched_rt_class(); 7163} 7164#else 7165void __init sched_init_smp(void) 7166{ 7167 sched_init_granularity(); 7168} 7169#endif /* CONFIG_SMP */ 7170 7171const_debug unsigned int sysctl_timer_migration = 1; 7172 7173int in_sched_functions(unsigned long addr) 7174{ 7175 return in_lock_functions(addr) || 7176 (addr >= (unsigned long)__sched_text_start 7177 && addr < (unsigned long)__sched_text_end); 7178} 7179 7180#ifdef CONFIG_CGROUP_SCHED 7181struct task_group root_task_group; 7182#endif 7183 7184DECLARE_PER_CPU(cpumask_var_t, load_balance_tmpmask); 7185 7186void __init sched_init(void) 7187{ 7188 int i, j; 7189 unsigned long alloc_size = 0, ptr; 7190 7191#ifdef CONFIG_FAIR_GROUP_SCHED 7192 alloc_size += 2 * nr_cpu_ids * sizeof(void **); 7193#endif 7194#ifdef CONFIG_RT_GROUP_SCHED 7195 alloc_size += 2 * nr_cpu_ids * sizeof(void **); 7196#endif 7197#ifdef CONFIG_CPUMASK_OFFSTACK 7198 alloc_size += num_possible_cpus() * cpumask_size(); 7199#endif 7200 if (alloc_size) { 7201 ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT); 7202 7203#ifdef CONFIG_FAIR_GROUP_SCHED 7204 root_task_group.se = (struct sched_entity **)ptr; 7205 ptr += nr_cpu_ids * sizeof(void **); 7206 7207 root_task_group.cfs_rq = (struct cfs_rq **)ptr; 7208 ptr += nr_cpu_ids * sizeof(void **); 7209 7210#endif /* CONFIG_FAIR_GROUP_SCHED */ 7211#ifdef CONFIG_RT_GROUP_SCHED 7212 root_task_group.rt_se = (struct sched_rt_entity **)ptr; 7213 ptr += nr_cpu_ids * sizeof(void **); 7214 7215 root_task_group.rt_rq = (struct rt_rq **)ptr; 7216 ptr += nr_cpu_ids * sizeof(void **); 7217 7218#endif /* CONFIG_RT_GROUP_SCHED */ 7219#ifdef CONFIG_CPUMASK_OFFSTACK 7220 for_each_possible_cpu(i) { 7221 per_cpu(load_balance_tmpmask, i) = (void *)ptr; 7222 ptr += cpumask_size(); 7223 } 7224#endif /* CONFIG_CPUMASK_OFFSTACK */ 7225 } 7226 7227#ifdef CONFIG_SMP 7228 init_defrootdomain(); 7229#endif 7230 7231 init_rt_bandwidth(&def_rt_bandwidth, 7232 global_rt_period(), global_rt_runtime()); 7233 7234#ifdef CONFIG_RT_GROUP_SCHED 7235 init_rt_bandwidth(&root_task_group.rt_bandwidth, 7236 global_rt_period(), global_rt_runtime()); 7237#endif /* CONFIG_RT_GROUP_SCHED */ 7238 7239#ifdef CONFIG_CGROUP_SCHED 7240 list_add(&root_task_group.list, &task_groups); 7241 INIT_LIST_HEAD(&root_task_group.children); 7242 INIT_LIST_HEAD(&root_task_group.siblings); 7243 autogroup_init(&init_task); 7244 7245#endif /* CONFIG_CGROUP_SCHED */ 7246 7247#ifdef CONFIG_CGROUP_CPUACCT 7248 root_cpuacct.cpustat = &kernel_cpustat; 7249 root_cpuacct.cpuusage = alloc_percpu(u64); 7250 /* Too early, not expected to fail */ 7251 BUG_ON(!root_cpuacct.cpuusage); 7252#endif 7253 for_each_possible_cpu(i) { 7254 struct rq *rq; 7255 7256 rq = cpu_rq(i); 7257 raw_spin_lock_init(&rq->lock); 7258 rq->nr_running = 0; 7259 rq->calc_load_active = 0; 7260 rq->calc_load_update = jiffies + LOAD_FREQ; 7261 init_cfs_rq(&rq->cfs); 7262 init_rt_rq(&rq->rt, rq); 7263#ifdef CONFIG_FAIR_GROUP_SCHED 7264 root_task_group.shares = ROOT_TASK_GROUP_LOAD; 7265 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list); 7266 /* 7267 * How much cpu bandwidth does root_task_group get? 7268 * 7269 * In case of task-groups formed thr' the cgroup filesystem, it 7270 * gets 100% of the cpu resources in the system. This overall 7271 * system cpu resource is divided among the tasks of 7272 * root_task_group and its child task-groups in a fair manner, 7273 * based on each entity's (task or task-group's) weight 7274 * (se->load.weight). 7275 * 7276 * In other words, if root_task_group has 10 tasks of weight 7277 * 1024) and two child groups A0 and A1 (of weight 1024 each), 7278 * then A0's share of the cpu resource is: 7279 * 7280 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33% 7281 * 7282 * We achieve this by letting root_task_group's tasks sit 7283 * directly in rq->cfs (i.e root_task_group->se[] = NULL). 7284 */ 7285 init_cfs_bandwidth(&root_task_group.cfs_bandwidth); 7286 init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL); 7287#endif /* CONFIG_FAIR_GROUP_SCHED */ 7288 7289 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime; 7290#ifdef CONFIG_RT_GROUP_SCHED 7291 INIT_LIST_HEAD(&rq->leaf_rt_rq_list); 7292 init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL); 7293#endif 7294 7295 for (j = 0; j < CPU_LOAD_IDX_MAX; j++) 7296 rq->cpu_load[j] = 0; 7297 7298 rq->last_load_update_tick = jiffies; 7299 7300#ifdef CONFIG_SMP 7301 rq->sd = NULL; 7302 rq->rd = NULL; 7303 rq->cpu_power = SCHED_POWER_SCALE; 7304 rq->post_schedule = 0; 7305 rq->active_balance = 0; 7306 rq->next_balance = jiffies; 7307 rq->push_cpu = 0; 7308 rq->cpu = i; 7309 rq->online = 0; 7310 rq->idle_stamp = 0; 7311 rq->avg_idle = 2*sysctl_sched_migration_cost; 7312 7313 INIT_LIST_HEAD(&rq->cfs_tasks); 7314 7315 rq_attach_root(rq, &def_root_domain); 7316#ifdef CONFIG_NO_HZ 7317 rq->nohz_flags = 0; 7318#endif 7319#endif 7320 init_rq_hrtick(rq); 7321 atomic_set(&rq->nr_iowait, 0); 7322 } 7323 7324 set_load_weight(&init_task); 7325 7326#ifdef CONFIG_PREEMPT_NOTIFIERS 7327 INIT_HLIST_HEAD(&init_task.preempt_notifiers); 7328#endif 7329 7330#ifdef CONFIG_RT_MUTEXES 7331 plist_head_init(&init_task.pi_waiters); 7332#endif 7333 7334 /* 7335 * The boot idle thread does lazy MMU switching as well: 7336 */ 7337 atomic_inc(&init_mm.mm_count); 7338 enter_lazy_tlb(&init_mm, current); 7339 7340 /* 7341 * Make us the idle thread. Technically, schedule() should not be 7342 * called from this thread, however somewhere below it might be, 7343 * but because we are the idle thread, we just pick up running again 7344 * when this runqueue becomes "idle". 7345 */ 7346 init_idle(current, smp_processor_id()); 7347 7348 calc_load_update = jiffies + LOAD_FREQ; 7349 7350 /* 7351 * During early bootup we pretend to be a normal task: 7352 */ 7353 current->sched_class = &fair_sched_class; 7354 7355#ifdef CONFIG_SMP 7356 zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT); 7357 /* May be allocated at isolcpus cmdline parse time */ 7358 if (cpu_isolated_map == NULL) 7359 zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT); 7360 idle_thread_set_boot_cpu(); 7361#endif 7362 init_sched_fair_class(); 7363 7364 scheduler_running = 1; 7365} 7366 7367#ifdef CONFIG_DEBUG_ATOMIC_SLEEP 7368static inline int preempt_count_equals(int preempt_offset) 7369{ 7370 int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth(); 7371 7372 return (nested == preempt_offset); 7373} 7374 7375void __might_sleep(const char *file, int line, int preempt_offset) 7376{ 7377 static unsigned long prev_jiffy; /* ratelimiting */ 7378 7379 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */ 7380 if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) || 7381 system_state != SYSTEM_RUNNING || oops_in_progress) 7382 return; 7383 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) 7384 return; 7385 prev_jiffy = jiffies; 7386 7387 printk(KERN_ERR 7388 "BUG: sleeping function called from invalid context at %s:%d\n", 7389 file, line); 7390 printk(KERN_ERR 7391 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n", 7392 in_atomic(), irqs_disabled(), 7393 current->pid, current->comm); 7394 7395 debug_show_held_locks(current); 7396 if (irqs_disabled()) 7397 print_irqtrace_events(current); 7398 dump_stack(); 7399} 7400EXPORT_SYMBOL(__might_sleep); 7401#endif 7402 7403#ifdef CONFIG_MAGIC_SYSRQ 7404static void normalize_task(struct rq *rq, struct task_struct *p) 7405{ 7406 const struct sched_class *prev_class = p->sched_class; 7407 int old_prio = p->prio; 7408 int on_rq; 7409 7410 on_rq = p->on_rq; 7411 if (on_rq) 7412 dequeue_task(rq, p, 0); 7413 __setscheduler(rq, p, SCHED_NORMAL, 0); 7414 if (on_rq) { 7415 enqueue_task(rq, p, 0); 7416 resched_task(rq->curr); 7417 } 7418 7419 check_class_changed(rq, p, prev_class, old_prio); 7420} 7421 7422void normalize_rt_tasks(void) 7423{ 7424 struct task_struct *g, *p; 7425 unsigned long flags; 7426 struct rq *rq; 7427 7428 read_lock_irqsave(&tasklist_lock, flags); 7429 do_each_thread(g, p) { 7430 /* 7431 * Only normalize user tasks: 7432 */ 7433 if (!p->mm) 7434 continue; 7435 7436 p->se.exec_start = 0; 7437#ifdef CONFIG_SCHEDSTATS 7438 p->se.statistics.wait_start = 0; 7439 p->se.statistics.sleep_start = 0; 7440 p->se.statistics.block_start = 0; 7441#endif 7442 7443 if (!rt_task(p)) { 7444 /* 7445 * Renice negative nice level userspace 7446 * tasks back to 0: 7447 */ 7448 if (TASK_NICE(p) < 0 && p->mm) 7449 set_user_nice(p, 0); 7450 continue; 7451 } 7452 7453 raw_spin_lock(&p->pi_lock); 7454 rq = __task_rq_lock(p); 7455 7456 normalize_task(rq, p); 7457 7458 __task_rq_unlock(rq); 7459 raw_spin_unlock(&p->pi_lock); 7460 } while_each_thread(g, p); 7461 7462 read_unlock_irqrestore(&tasklist_lock, flags); 7463} 7464 7465#endif /* CONFIG_MAGIC_SYSRQ */ 7466 7467#if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) 7468/* 7469 * These functions are only useful for the IA64 MCA handling, or kdb. 7470 * 7471 * They can only be called when the whole system has been 7472 * stopped - every CPU needs to be quiescent, and no scheduling 7473 * activity can take place. Using them for anything else would 7474 * be a serious bug, and as a result, they aren't even visible 7475 * under any other configuration. 7476 */ 7477 7478/** 7479 * curr_task - return the current task for a given cpu. 7480 * @cpu: the processor in question. 7481 * 7482 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! 7483 */ 7484struct task_struct *curr_task(int cpu) 7485{ 7486 return cpu_curr(cpu); 7487} 7488 7489#endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */ 7490 7491#ifdef CONFIG_IA64 7492/** 7493 * set_curr_task - set the current task for a given cpu. 7494 * @cpu: the processor in question. 7495 * @p: the task pointer to set. 7496 * 7497 * Description: This function must only be used when non-maskable interrupts 7498 * are serviced on a separate stack. It allows the architecture to switch the 7499 * notion of the current task on a cpu in a non-blocking manner. This function 7500 * must be called with all CPU's synchronized, and interrupts disabled, the 7501 * and caller must save the original value of the current task (see 7502 * curr_task() above) and restore that value before reenabling interrupts and 7503 * re-starting the system. 7504 * 7505 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! 7506 */ 7507void set_curr_task(int cpu, struct task_struct *p) 7508{ 7509 cpu_curr(cpu) = p; 7510} 7511 7512#endif 7513 7514#ifdef CONFIG_CGROUP_SCHED 7515/* task_group_lock serializes the addition/removal of task groups */ 7516static DEFINE_SPINLOCK(task_group_lock); 7517 7518static void free_sched_group(struct task_group *tg) 7519{ 7520 free_fair_sched_group(tg); 7521 free_rt_sched_group(tg); 7522 autogroup_free(tg); 7523 kfree(tg); 7524} 7525 7526/* allocate runqueue etc for a new task group */ 7527struct task_group *sched_create_group(struct task_group *parent) 7528{ 7529 struct task_group *tg; 7530 unsigned long flags; 7531 7532 tg = kzalloc(sizeof(*tg), GFP_KERNEL); 7533 if (!tg) 7534 return ERR_PTR(-ENOMEM); 7535 7536 if (!alloc_fair_sched_group(tg, parent)) 7537 goto err; 7538 7539 if (!alloc_rt_sched_group(tg, parent)) 7540 goto err; 7541 7542 spin_lock_irqsave(&task_group_lock, flags); 7543 list_add_rcu(&tg->list, &task_groups); 7544 7545 WARN_ON(!parent); /* root should already exist */ 7546 7547 tg->parent = parent; 7548 INIT_LIST_HEAD(&tg->children); 7549 list_add_rcu(&tg->siblings, &parent->children); 7550 spin_unlock_irqrestore(&task_group_lock, flags); 7551 7552 return tg; 7553 7554err: 7555 free_sched_group(tg); 7556 return ERR_PTR(-ENOMEM); 7557} 7558 7559/* rcu callback to free various structures associated with a task group */ 7560static void free_sched_group_rcu(struct rcu_head *rhp) 7561{ 7562 /* now it should be safe to free those cfs_rqs */ 7563 free_sched_group(container_of(rhp, struct task_group, rcu)); 7564} 7565 7566/* Destroy runqueue etc associated with a task group */ 7567void sched_destroy_group(struct task_group *tg) 7568{ 7569 unsigned long flags; 7570 int i; 7571 7572 /* end participation in shares distribution */ 7573 for_each_possible_cpu(i) 7574 unregister_fair_sched_group(tg, i); 7575 7576 spin_lock_irqsave(&task_group_lock, flags); 7577 list_del_rcu(&tg->list); 7578 list_del_rcu(&tg->siblings); 7579 spin_unlock_irqrestore(&task_group_lock, flags); 7580 7581 /* wait for possible concurrent references to cfs_rqs complete */ 7582 call_rcu(&tg->rcu, free_sched_group_rcu); 7583} 7584 7585/* change task's runqueue when it moves between groups. 7586 * The caller of this function should have put the task in its new group 7587 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to 7588 * reflect its new group. 7589 */ 7590void sched_move_task(struct task_struct *tsk) 7591{ 7592 int on_rq, running; 7593 unsigned long flags; 7594 struct rq *rq; 7595 7596 rq = task_rq_lock(tsk, &flags); 7597 7598 running = task_current(rq, tsk); 7599 on_rq = tsk->on_rq; 7600 7601 if (on_rq) 7602 dequeue_task(rq, tsk, 0); 7603 if (unlikely(running)) 7604 tsk->sched_class->put_prev_task(rq, tsk); 7605 7606#ifdef CONFIG_FAIR_GROUP_SCHED 7607 if (tsk->sched_class->task_move_group) 7608 tsk->sched_class->task_move_group(tsk, on_rq); 7609 else 7610#endif 7611 set_task_rq(tsk, task_cpu(tsk)); 7612 7613 if (unlikely(running)) 7614 tsk->sched_class->set_curr_task(rq); 7615 if (on_rq) 7616 enqueue_task(rq, tsk, 0); 7617 7618 task_rq_unlock(rq, tsk, &flags); 7619} 7620#endif /* CONFIG_CGROUP_SCHED */ 7621 7622#if defined(CONFIG_RT_GROUP_SCHED) || defined(CONFIG_CFS_BANDWIDTH) 7623static unsigned long to_ratio(u64 period, u64 runtime) 7624{ 7625 if (runtime == RUNTIME_INF) 7626 return 1ULL << 20; 7627 7628 return div64_u64(runtime << 20, period); 7629} 7630#endif 7631 7632#ifdef CONFIG_RT_GROUP_SCHED 7633/* 7634 * Ensure that the real time constraints are schedulable. 7635 */ 7636static DEFINE_MUTEX(rt_constraints_mutex); 7637 7638/* Must be called with tasklist_lock held */ 7639static inline int tg_has_rt_tasks(struct task_group *tg) 7640{ 7641 struct task_struct *g, *p; 7642 7643 do_each_thread(g, p) { 7644 if (rt_task(p) && task_rq(p)->rt.tg == tg) 7645 return 1; 7646 } while_each_thread(g, p); 7647 7648 return 0; 7649} 7650 7651struct rt_schedulable_data { 7652 struct task_group *tg; 7653 u64 rt_period; 7654 u64 rt_runtime; 7655}; 7656 7657static int tg_rt_schedulable(struct task_group *tg, void *data) 7658{ 7659 struct rt_schedulable_data *d = data; 7660 struct task_group *child; 7661 unsigned long total, sum = 0; 7662 u64 period, runtime; 7663 7664 period = ktime_to_ns(tg->rt_bandwidth.rt_period); 7665 runtime = tg->rt_bandwidth.rt_runtime; 7666 7667 if (tg == d->tg) { 7668 period = d->rt_period; 7669 runtime = d->rt_runtime; 7670 } 7671 7672 /* 7673 * Cannot have more runtime than the period. 7674 */ 7675 if (runtime > period && runtime != RUNTIME_INF) 7676 return -EINVAL; 7677 7678 /* 7679 * Ensure we don't starve existing RT tasks. 7680 */ 7681 if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg)) 7682 return -EBUSY; 7683 7684 total = to_ratio(period, runtime); 7685 7686 /* 7687 * Nobody can have more than the global setting allows. 7688 */ 7689 if (total > to_ratio(global_rt_period(), global_rt_runtime())) 7690 return -EINVAL; 7691 7692 /* 7693 * The sum of our children's runtime should not exceed our own. 7694 */ 7695 list_for_each_entry_rcu(child, &tg->children, siblings) { 7696 period = ktime_to_ns(child->rt_bandwidth.rt_period); 7697 runtime = child->rt_bandwidth.rt_runtime; 7698 7699 if (child == d->tg) { 7700 period = d->rt_period; 7701 runtime = d->rt_runtime; 7702 } 7703 7704 sum += to_ratio(period, runtime); 7705 } 7706 7707 if (sum > total) 7708 return -EINVAL; 7709 7710 return 0; 7711} 7712 7713static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime) 7714{ 7715 int ret; 7716 7717 struct rt_schedulable_data data = { 7718 .tg = tg, 7719 .rt_period = period, 7720 .rt_runtime = runtime, 7721 }; 7722 7723 rcu_read_lock(); 7724 ret = walk_tg_tree(tg_rt_schedulable, tg_nop, &data); 7725 rcu_read_unlock(); 7726 7727 return ret; 7728} 7729 7730static int tg_set_rt_bandwidth(struct task_group *tg, 7731 u64 rt_period, u64 rt_runtime) 7732{ 7733 int i, err = 0; 7734 7735 mutex_lock(&rt_constraints_mutex); 7736 read_lock(&tasklist_lock); 7737 err = __rt_schedulable(tg, rt_period, rt_runtime); 7738 if (err) 7739 goto unlock; 7740 7741 raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock); 7742 tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period); 7743 tg->rt_bandwidth.rt_runtime = rt_runtime; 7744 7745 for_each_possible_cpu(i) { 7746 struct rt_rq *rt_rq = tg->rt_rq[i]; 7747 7748 raw_spin_lock(&rt_rq->rt_runtime_lock); 7749 rt_rq->rt_runtime = rt_runtime; 7750 raw_spin_unlock(&rt_rq->rt_runtime_lock); 7751 } 7752 raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock); 7753unlock: 7754 read_unlock(&tasklist_lock); 7755 mutex_unlock(&rt_constraints_mutex); 7756 7757 return err; 7758} 7759 7760int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us) 7761{ 7762 u64 rt_runtime, rt_period; 7763 7764 rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period); 7765 rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC; 7766 if (rt_runtime_us < 0) 7767 rt_runtime = RUNTIME_INF; 7768 7769 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); 7770} 7771 7772long sched_group_rt_runtime(struct task_group *tg) 7773{ 7774 u64 rt_runtime_us; 7775 7776 if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF) 7777 return -1; 7778 7779 rt_runtime_us = tg->rt_bandwidth.rt_runtime; 7780 do_div(rt_runtime_us, NSEC_PER_USEC); 7781 return rt_runtime_us; 7782} 7783 7784int sched_group_set_rt_period(struct task_group *tg, long rt_period_us) 7785{ 7786 u64 rt_runtime, rt_period; 7787 7788 rt_period = (u64)rt_period_us * NSEC_PER_USEC; 7789 rt_runtime = tg->rt_bandwidth.rt_runtime; 7790 7791 if (rt_period == 0) 7792 return -EINVAL; 7793 7794 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); 7795} 7796 7797long sched_group_rt_period(struct task_group *tg) 7798{ 7799 u64 rt_period_us; 7800 7801 rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period); 7802 do_div(rt_period_us, NSEC_PER_USEC); 7803 return rt_period_us; 7804} 7805 7806static int sched_rt_global_constraints(void) 7807{ 7808 u64 runtime, period; 7809 int ret = 0; 7810 7811 if (sysctl_sched_rt_period <= 0) 7812 return -EINVAL; 7813 7814 runtime = global_rt_runtime(); 7815 period = global_rt_period(); 7816 7817 /* 7818 * Sanity check on the sysctl variables. 7819 */ 7820 if (runtime > period && runtime != RUNTIME_INF) 7821 return -EINVAL; 7822 7823 mutex_lock(&rt_constraints_mutex); 7824 read_lock(&tasklist_lock); 7825 ret = __rt_schedulable(NULL, 0, 0); 7826 read_unlock(&tasklist_lock); 7827 mutex_unlock(&rt_constraints_mutex); 7828 7829 return ret; 7830} 7831 7832int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk) 7833{ 7834 /* Don't accept realtime tasks when there is no way for them to run */ 7835 if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0) 7836 return 0; 7837 7838 return 1; 7839} 7840 7841#else /* !CONFIG_RT_GROUP_SCHED */ 7842static int sched_rt_global_constraints(void) 7843{ 7844 unsigned long flags; 7845 int i; 7846 7847 if (sysctl_sched_rt_period <= 0) 7848 return -EINVAL; 7849 7850 /* 7851 * There's always some RT tasks in the root group 7852 * -- migration, kstopmachine etc.. 7853 */ 7854 if (sysctl_sched_rt_runtime == 0) 7855 return -EBUSY; 7856 7857 raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags); 7858 for_each_possible_cpu(i) { 7859 struct rt_rq *rt_rq = &cpu_rq(i)->rt; 7860 7861 raw_spin_lock(&rt_rq->rt_runtime_lock); 7862 rt_rq->rt_runtime = global_rt_runtime(); 7863 raw_spin_unlock(&rt_rq->rt_runtime_lock); 7864 } 7865 raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags); 7866 7867 return 0; 7868} 7869#endif /* CONFIG_RT_GROUP_SCHED */ 7870 7871int sched_rt_handler(struct ctl_table *table, int write, 7872 void __user *buffer, size_t *lenp, 7873 loff_t *ppos) 7874{ 7875 int ret; 7876 int old_period, old_runtime; 7877 static DEFINE_MUTEX(mutex); 7878 7879 mutex_lock(&mutex); 7880 old_period = sysctl_sched_rt_period; 7881 old_runtime = sysctl_sched_rt_runtime; 7882 7883 ret = proc_dointvec(table, write, buffer, lenp, ppos); 7884 7885 if (!ret && write) { 7886 ret = sched_rt_global_constraints(); 7887 if (ret) { 7888 sysctl_sched_rt_period = old_period; 7889 sysctl_sched_rt_runtime = old_runtime; 7890 } else { 7891 def_rt_bandwidth.rt_runtime = global_rt_runtime(); 7892 def_rt_bandwidth.rt_period = 7893 ns_to_ktime(global_rt_period()); 7894 } 7895 } 7896 mutex_unlock(&mutex); 7897 7898 return ret; 7899} 7900 7901#ifdef CONFIG_CGROUP_SCHED 7902 7903/* return corresponding task_group object of a cgroup */ 7904static inline struct task_group *cgroup_tg(struct cgroup *cgrp) 7905{ 7906 return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id), 7907 struct task_group, css); 7908} 7909 7910static struct cgroup_subsys_state *cpu_cgroup_create(struct cgroup *cgrp) 7911{ 7912 struct task_group *tg, *parent; 7913 7914 if (!cgrp->parent) { 7915 /* This is early initialization for the top cgroup */ 7916 return &root_task_group.css; 7917 } 7918 7919 parent = cgroup_tg(cgrp->parent); 7920 tg = sched_create_group(parent); 7921 if (IS_ERR(tg)) 7922 return ERR_PTR(-ENOMEM); 7923 7924 return &tg->css; 7925} 7926 7927static void cpu_cgroup_destroy(struct cgroup *cgrp) 7928{ 7929 struct task_group *tg = cgroup_tg(cgrp); 7930 7931 sched_destroy_group(tg); 7932} 7933 7934static int cpu_cgroup_can_attach(struct cgroup *cgrp, 7935 struct cgroup_taskset *tset) 7936{ 7937 struct task_struct *task; 7938 7939 cgroup_taskset_for_each(task, cgrp, tset) { 7940#ifdef CONFIG_RT_GROUP_SCHED 7941 if (!sched_rt_can_attach(cgroup_tg(cgrp), task)) 7942 return -EINVAL; 7943#else 7944 /* We don't support RT-tasks being in separate groups */ 7945 if (task->sched_class != &fair_sched_class) 7946 return -EINVAL; 7947#endif 7948 } 7949 return 0; 7950} 7951 7952static void cpu_cgroup_attach(struct cgroup *cgrp, 7953 struct cgroup_taskset *tset) 7954{ 7955 struct task_struct *task; 7956 7957 cgroup_taskset_for_each(task, cgrp, tset) 7958 sched_move_task(task); 7959} 7960 7961static void 7962cpu_cgroup_exit(struct cgroup *cgrp, struct cgroup *old_cgrp, 7963 struct task_struct *task) 7964{ 7965 /* 7966 * cgroup_exit() is called in the copy_process() failure path. 7967 * Ignore this case since the task hasn't ran yet, this avoids 7968 * trying to poke a half freed task state from generic code. 7969 */ 7970 if (!(task->flags & PF_EXITING)) 7971 return; 7972 7973 sched_move_task(task); 7974} 7975 7976#ifdef CONFIG_FAIR_GROUP_SCHED 7977static int cpu_shares_write_u64(struct cgroup *cgrp, struct cftype *cftype, 7978 u64 shareval) 7979{ 7980 return sched_group_set_shares(cgroup_tg(cgrp), scale_load(shareval)); 7981} 7982 7983static u64 cpu_shares_read_u64(struct cgroup *cgrp, struct cftype *cft) 7984{ 7985 struct task_group *tg = cgroup_tg(cgrp); 7986 7987 return (u64) scale_load_down(tg->shares); 7988} 7989 7990#ifdef CONFIG_CFS_BANDWIDTH 7991static DEFINE_MUTEX(cfs_constraints_mutex); 7992 7993const u64 max_cfs_quota_period = 1 * NSEC_PER_SEC; /* 1s */ 7994const u64 min_cfs_quota_period = 1 * NSEC_PER_MSEC; /* 1ms */ 7995 7996static int __cfs_schedulable(struct task_group *tg, u64 period, u64 runtime); 7997 7998static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota) 7999{ 8000 int i, ret = 0, runtime_enabled, runtime_was_enabled; 8001 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 8002 8003 if (tg == &root_task_group) 8004 return -EINVAL; 8005 8006 /* 8007 * Ensure we have at some amount of bandwidth every period. This is 8008 * to prevent reaching a state of large arrears when throttled via 8009 * entity_tick() resulting in prolonged exit starvation. 8010 */ 8011 if (quota < min_cfs_quota_period || period < min_cfs_quota_period) 8012 return -EINVAL; 8013 8014 /* 8015 * Likewise, bound things on the otherside by preventing insane quota 8016 * periods. This also allows us to normalize in computing quota 8017 * feasibility. 8018 */ 8019 if (period > max_cfs_quota_period) 8020 return -EINVAL; 8021 8022 mutex_lock(&cfs_constraints_mutex); 8023 ret = __cfs_schedulable(tg, period, quota); 8024 if (ret) 8025 goto out_unlock; 8026 8027 runtime_enabled = quota != RUNTIME_INF; 8028 runtime_was_enabled = cfs_b->quota != RUNTIME_INF; 8029 account_cfs_bandwidth_used(runtime_enabled, runtime_was_enabled); 8030 raw_spin_lock_irq(&cfs_b->lock); 8031 cfs_b->period = ns_to_ktime(period); 8032 cfs_b->quota = quota; 8033 8034 __refill_cfs_bandwidth_runtime(cfs_b); 8035 /* restart the period timer (if active) to handle new period expiry */ 8036 if (runtime_enabled && cfs_b->timer_active) { 8037 /* force a reprogram */ 8038 cfs_b->timer_active = 0; 8039 __start_cfs_bandwidth(cfs_b); 8040 } 8041 raw_spin_unlock_irq(&cfs_b->lock); 8042 8043 for_each_possible_cpu(i) { 8044 struct cfs_rq *cfs_rq = tg->cfs_rq[i]; 8045 struct rq *rq = cfs_rq->rq; 8046 8047 raw_spin_lock_irq(&rq->lock); 8048 cfs_rq->runtime_enabled = runtime_enabled; 8049 cfs_rq->runtime_remaining = 0; 8050 8051 if (cfs_rq->throttled) 8052 unthrottle_cfs_rq(cfs_rq); 8053 raw_spin_unlock_irq(&rq->lock); 8054 } 8055out_unlock: 8056 mutex_unlock(&cfs_constraints_mutex); 8057 8058 return ret; 8059} 8060 8061int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us) 8062{ 8063 u64 quota, period; 8064 8065 period = ktime_to_ns(tg->cfs_bandwidth.period); 8066 if (cfs_quota_us < 0) 8067 quota = RUNTIME_INF; 8068 else 8069 quota = (u64)cfs_quota_us * NSEC_PER_USEC; 8070 8071 return tg_set_cfs_bandwidth(tg, period, quota); 8072} 8073 8074long tg_get_cfs_quota(struct task_group *tg) 8075{ 8076 u64 quota_us; 8077 8078 if (tg->cfs_bandwidth.quota == RUNTIME_INF) 8079 return -1; 8080 8081 quota_us = tg->cfs_bandwidth.quota; 8082 do_div(quota_us, NSEC_PER_USEC); 8083 8084 return quota_us; 8085} 8086 8087int tg_set_cfs_period(struct task_group *tg, long cfs_period_us) 8088{ 8089 u64 quota, period; 8090 8091 period = (u64)cfs_period_us * NSEC_PER_USEC; 8092 quota = tg->cfs_bandwidth.quota; 8093 8094 return tg_set_cfs_bandwidth(tg, period, quota); 8095} 8096 8097long tg_get_cfs_period(struct task_group *tg) 8098{ 8099 u64 cfs_period_us; 8100 8101 cfs_period_us = ktime_to_ns(tg->cfs_bandwidth.period); 8102 do_div(cfs_period_us, NSEC_PER_USEC); 8103 8104 return cfs_period_us; 8105} 8106 8107static s64 cpu_cfs_quota_read_s64(struct cgroup *cgrp, struct cftype *cft) 8108{ 8109 return tg_get_cfs_quota(cgroup_tg(cgrp)); 8110} 8111 8112static int cpu_cfs_quota_write_s64(struct cgroup *cgrp, struct cftype *cftype, 8113 s64 cfs_quota_us) 8114{ 8115 return tg_set_cfs_quota(cgroup_tg(cgrp), cfs_quota_us); 8116} 8117 8118static u64 cpu_cfs_period_read_u64(struct cgroup *cgrp, struct cftype *cft) 8119{ 8120 return tg_get_cfs_period(cgroup_tg(cgrp)); 8121} 8122 8123static int cpu_cfs_period_write_u64(struct cgroup *cgrp, struct cftype *cftype, 8124 u64 cfs_period_us) 8125{ 8126 return tg_set_cfs_period(cgroup_tg(cgrp), cfs_period_us); 8127} 8128 8129struct cfs_schedulable_data { 8130 struct task_group *tg; 8131 u64 period, quota; 8132}; 8133 8134/* 8135 * normalize group quota/period to be quota/max_period 8136 * note: units are usecs 8137 */ 8138static u64 normalize_cfs_quota(struct task_group *tg, 8139 struct cfs_schedulable_data *d) 8140{ 8141 u64 quota, period; 8142 8143 if (tg == d->tg) { 8144 period = d->period; 8145 quota = d->quota; 8146 } else { 8147 period = tg_get_cfs_period(tg); 8148 quota = tg_get_cfs_quota(tg); 8149 } 8150 8151 /* note: these should typically be equivalent */ 8152 if (quota == RUNTIME_INF || quota == -1) 8153 return RUNTIME_INF; 8154 8155 return to_ratio(period, quota); 8156} 8157 8158static int tg_cfs_schedulable_down(struct task_group *tg, void *data) 8159{ 8160 struct cfs_schedulable_data *d = data; 8161 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 8162 s64 quota = 0, parent_quota = -1; 8163 8164 if (!tg->parent) { 8165 quota = RUNTIME_INF; 8166 } else { 8167 struct cfs_bandwidth *parent_b = &tg->parent->cfs_bandwidth; 8168 8169 quota = normalize_cfs_quota(tg, d); 8170 parent_quota = parent_b->hierarchal_quota; 8171 8172 /* 8173 * ensure max(child_quota) <= parent_quota, inherit when no 8174 * limit is set 8175 */ 8176 if (quota == RUNTIME_INF) 8177 quota = parent_quota; 8178 else if (parent_quota != RUNTIME_INF && quota > parent_quota) 8179 return -EINVAL; 8180 } 8181 cfs_b->hierarchal_quota = quota; 8182 8183 return 0; 8184} 8185 8186static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota) 8187{ 8188 int ret; 8189 struct cfs_schedulable_data data = { 8190 .tg = tg, 8191 .period = period, 8192 .quota = quota, 8193 }; 8194 8195 if (quota != RUNTIME_INF) { 8196 do_div(data.period, NSEC_PER_USEC); 8197 do_div(data.quota, NSEC_PER_USEC); 8198 } 8199 8200 rcu_read_lock(); 8201 ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data); 8202 rcu_read_unlock(); 8203 8204 return ret; 8205} 8206 8207static int cpu_stats_show(struct cgroup *cgrp, struct cftype *cft, 8208 struct cgroup_map_cb *cb) 8209{ 8210 struct task_group *tg = cgroup_tg(cgrp); 8211 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 8212 8213 cb->fill(cb, "nr_periods", cfs_b->nr_periods); 8214 cb->fill(cb, "nr_throttled", cfs_b->nr_throttled); 8215 cb->fill(cb, "throttled_time", cfs_b->throttled_time); 8216 8217 return 0; 8218} 8219#endif /* CONFIG_CFS_BANDWIDTH */ 8220#endif /* CONFIG_FAIR_GROUP_SCHED */ 8221 8222#ifdef CONFIG_RT_GROUP_SCHED 8223static int cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft, 8224 s64 val) 8225{ 8226 return sched_group_set_rt_runtime(cgroup_tg(cgrp), val); 8227} 8228 8229static s64 cpu_rt_runtime_read(struct cgroup *cgrp, struct cftype *cft) 8230{ 8231 return sched_group_rt_runtime(cgroup_tg(cgrp)); 8232} 8233 8234static int cpu_rt_period_write_uint(struct cgroup *cgrp, struct cftype *cftype, 8235 u64 rt_period_us) 8236{ 8237 return sched_group_set_rt_period(cgroup_tg(cgrp), rt_period_us); 8238} 8239 8240static u64 cpu_rt_period_read_uint(struct cgroup *cgrp, struct cftype *cft) 8241{ 8242 return sched_group_rt_period(cgroup_tg(cgrp)); 8243} 8244#endif /* CONFIG_RT_GROUP_SCHED */ 8245 8246static struct cftype cpu_files[] = { 8247#ifdef CONFIG_FAIR_GROUP_SCHED 8248 { 8249 .name = "shares", 8250 .read_u64 = cpu_shares_read_u64, 8251 .write_u64 = cpu_shares_write_u64, 8252 }, 8253#endif 8254#ifdef CONFIG_CFS_BANDWIDTH 8255 { 8256 .name = "cfs_quota_us", 8257 .read_s64 = cpu_cfs_quota_read_s64, 8258 .write_s64 = cpu_cfs_quota_write_s64, 8259 }, 8260 { 8261 .name = "cfs_period_us", 8262 .read_u64 = cpu_cfs_period_read_u64, 8263 .write_u64 = cpu_cfs_period_write_u64, 8264 }, 8265 { 8266 .name = "stat", 8267 .read_map = cpu_stats_show, 8268 }, 8269#endif 8270#ifdef CONFIG_RT_GROUP_SCHED 8271 { 8272 .name = "rt_runtime_us", 8273 .read_s64 = cpu_rt_runtime_read, 8274 .write_s64 = cpu_rt_runtime_write, 8275 }, 8276 { 8277 .name = "rt_period_us", 8278 .read_u64 = cpu_rt_period_read_uint, 8279 .write_u64 = cpu_rt_period_write_uint, 8280 }, 8281#endif 8282 { } /* terminate */ 8283}; 8284 8285struct cgroup_subsys cpu_cgroup_subsys = { 8286 .name = "cpu", 8287 .create = cpu_cgroup_create, 8288 .destroy = cpu_cgroup_destroy, 8289 .can_attach = cpu_cgroup_can_attach, 8290 .attach = cpu_cgroup_attach, 8291 .exit = cpu_cgroup_exit, 8292 .subsys_id = cpu_cgroup_subsys_id, 8293 .base_cftypes = cpu_files, 8294 .early_init = 1, 8295}; 8296 8297#endif /* CONFIG_CGROUP_SCHED */ 8298 8299#ifdef CONFIG_CGROUP_CPUACCT 8300 8301/* 8302 * CPU accounting code for task groups. 8303 * 8304 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh 8305 * (balbir@in.ibm.com). 8306 */ 8307 8308/* create a new cpu accounting group */ 8309static struct cgroup_subsys_state *cpuacct_create(struct cgroup *cgrp) 8310{ 8311 struct cpuacct *ca; 8312 8313 if (!cgrp->parent) 8314 return &root_cpuacct.css; 8315 8316 ca = kzalloc(sizeof(*ca), GFP_KERNEL); 8317 if (!ca) 8318 goto out; 8319 8320 ca->cpuusage = alloc_percpu(u64); 8321 if (!ca->cpuusage) 8322 goto out_free_ca; 8323 8324 ca->cpustat = alloc_percpu(struct kernel_cpustat); 8325 if (!ca->cpustat) 8326 goto out_free_cpuusage; 8327 8328 return &ca->css; 8329 8330out_free_cpuusage: 8331 free_percpu(ca->cpuusage); 8332out_free_ca: 8333 kfree(ca); 8334out: 8335 return ERR_PTR(-ENOMEM); 8336} 8337 8338/* destroy an existing cpu accounting group */ 8339static void cpuacct_destroy(struct cgroup *cgrp) 8340{ 8341 struct cpuacct *ca = cgroup_ca(cgrp); 8342 8343 free_percpu(ca->cpustat); 8344 free_percpu(ca->cpuusage); 8345 kfree(ca); 8346} 8347 8348static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu) 8349{ 8350 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); 8351 u64 data; 8352 8353#ifndef CONFIG_64BIT 8354 /* 8355 * Take rq->lock to make 64-bit read safe on 32-bit platforms. 8356 */ 8357 raw_spin_lock_irq(&cpu_rq(cpu)->lock); 8358 data = *cpuusage; 8359 raw_spin_unlock_irq(&cpu_rq(cpu)->lock); 8360#else 8361 data = *cpuusage; 8362#endif 8363 8364 return data; 8365} 8366 8367static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val) 8368{ 8369 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); 8370 8371#ifndef CONFIG_64BIT 8372 /* 8373 * Take rq->lock to make 64-bit write safe on 32-bit platforms. 8374 */ 8375 raw_spin_lock_irq(&cpu_rq(cpu)->lock); 8376 *cpuusage = val; 8377 raw_spin_unlock_irq(&cpu_rq(cpu)->lock); 8378#else 8379 *cpuusage = val; 8380#endif 8381} 8382 8383/* return total cpu usage (in nanoseconds) of a group */ 8384static u64 cpuusage_read(struct cgroup *cgrp, struct cftype *cft) 8385{ 8386 struct cpuacct *ca = cgroup_ca(cgrp); 8387 u64 totalcpuusage = 0; 8388 int i; 8389 8390 for_each_present_cpu(i) 8391 totalcpuusage += cpuacct_cpuusage_read(ca, i); 8392 8393 return totalcpuusage; 8394} 8395 8396static int cpuusage_write(struct cgroup *cgrp, struct cftype *cftype, 8397 u64 reset) 8398{ 8399 struct cpuacct *ca = cgroup_ca(cgrp); 8400 int err = 0; 8401 int i; 8402 8403 if (reset) { 8404 err = -EINVAL; 8405 goto out; 8406 } 8407 8408 for_each_present_cpu(i) 8409 cpuacct_cpuusage_write(ca, i, 0); 8410 8411out: 8412 return err; 8413} 8414 8415static int cpuacct_percpu_seq_read(struct cgroup *cgroup, struct cftype *cft, 8416 struct seq_file *m) 8417{ 8418 struct cpuacct *ca = cgroup_ca(cgroup); 8419 u64 percpu; 8420 int i; 8421 8422 for_each_present_cpu(i) { 8423 percpu = cpuacct_cpuusage_read(ca, i); 8424 seq_printf(m, "%llu ", (unsigned long long) percpu); 8425 } 8426 seq_printf(m, "\n"); 8427 return 0; 8428} 8429 8430static const char *cpuacct_stat_desc[] = { 8431 [CPUACCT_STAT_USER] = "user", 8432 [CPUACCT_STAT_SYSTEM] = "system", 8433}; 8434 8435static int cpuacct_stats_show(struct cgroup *cgrp, struct cftype *cft, 8436 struct cgroup_map_cb *cb) 8437{ 8438 struct cpuacct *ca = cgroup_ca(cgrp); 8439 int cpu; 8440 s64 val = 0; 8441 8442 for_each_online_cpu(cpu) { 8443 struct kernel_cpustat *kcpustat = per_cpu_ptr(ca->cpustat, cpu); 8444 val += kcpustat->cpustat[CPUTIME_USER]; 8445 val += kcpustat->cpustat[CPUTIME_NICE]; 8446 } 8447 val = cputime64_to_clock_t(val); 8448 cb->fill(cb, cpuacct_stat_desc[CPUACCT_STAT_USER], val); 8449 8450 val = 0; 8451 for_each_online_cpu(cpu) { 8452 struct kernel_cpustat *kcpustat = per_cpu_ptr(ca->cpustat, cpu); 8453 val += kcpustat->cpustat[CPUTIME_SYSTEM]; 8454 val += kcpustat->cpustat[CPUTIME_IRQ]; 8455 val += kcpustat->cpustat[CPUTIME_SOFTIRQ]; 8456 } 8457 8458 val = cputime64_to_clock_t(val); 8459 cb->fill(cb, cpuacct_stat_desc[CPUACCT_STAT_SYSTEM], val); 8460 8461 return 0; 8462} 8463 8464static struct cftype files[] = { 8465 { 8466 .name = "usage", 8467 .read_u64 = cpuusage_read, 8468 .write_u64 = cpuusage_write, 8469 }, 8470 { 8471 .name = "usage_percpu", 8472 .read_seq_string = cpuacct_percpu_seq_read, 8473 }, 8474 { 8475 .name = "stat", 8476 .read_map = cpuacct_stats_show, 8477 }, 8478 { } /* terminate */ 8479}; 8480 8481/* 8482 * charge this task's execution time to its accounting group. 8483 * 8484 * called with rq->lock held. 8485 */ 8486void cpuacct_charge(struct task_struct *tsk, u64 cputime) 8487{ 8488 struct cpuacct *ca; 8489 int cpu; 8490 8491 if (unlikely(!cpuacct_subsys.active)) 8492 return; 8493 8494 cpu = task_cpu(tsk); 8495 8496 rcu_read_lock(); 8497 8498 ca = task_ca(tsk); 8499 8500 for (; ca; ca = parent_ca(ca)) { 8501 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); 8502 *cpuusage += cputime; 8503 } 8504 8505 rcu_read_unlock(); 8506} 8507 8508struct cgroup_subsys cpuacct_subsys = { 8509 .name = "cpuacct", 8510 .create = cpuacct_create, 8511 .destroy = cpuacct_destroy, 8512 .subsys_id = cpuacct_subsys_id, 8513 .base_cftypes = files, 8514}; 8515#endif /* CONFIG_CGROUP_CPUACCT */ 8516