core.c revision de212f18e92c952533d57c5510d2790199c75734
1/* 2 * kernel/sched/core.c 3 * 4 * Kernel scheduler and related syscalls 5 * 6 * Copyright (C) 1991-2002 Linus Torvalds 7 * 8 * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and 9 * make semaphores SMP safe 10 * 1998-11-19 Implemented schedule_timeout() and related stuff 11 * by Andrea Arcangeli 12 * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar: 13 * hybrid priority-list and round-robin design with 14 * an array-switch method of distributing timeslices 15 * and per-CPU runqueues. Cleanups and useful suggestions 16 * by Davide Libenzi, preemptible kernel bits by Robert Love. 17 * 2003-09-03 Interactivity tuning by Con Kolivas. 18 * 2004-04-02 Scheduler domains code by Nick Piggin 19 * 2007-04-15 Work begun on replacing all interactivity tuning with a 20 * fair scheduling design by Con Kolivas. 21 * 2007-05-05 Load balancing (smp-nice) and other improvements 22 * by Peter Williams 23 * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith 24 * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri 25 * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins, 26 * Thomas Gleixner, Mike Kravetz 27 */ 28 29#include <linux/mm.h> 30#include <linux/module.h> 31#include <linux/nmi.h> 32#include <linux/init.h> 33#include <linux/uaccess.h> 34#include <linux/highmem.h> 35#include <asm/mmu_context.h> 36#include <linux/interrupt.h> 37#include <linux/capability.h> 38#include <linux/completion.h> 39#include <linux/kernel_stat.h> 40#include <linux/debug_locks.h> 41#include <linux/perf_event.h> 42#include <linux/security.h> 43#include <linux/notifier.h> 44#include <linux/profile.h> 45#include <linux/freezer.h> 46#include <linux/vmalloc.h> 47#include <linux/blkdev.h> 48#include <linux/delay.h> 49#include <linux/pid_namespace.h> 50#include <linux/smp.h> 51#include <linux/threads.h> 52#include <linux/timer.h> 53#include <linux/rcupdate.h> 54#include <linux/cpu.h> 55#include <linux/cpuset.h> 56#include <linux/percpu.h> 57#include <linux/proc_fs.h> 58#include <linux/seq_file.h> 59#include <linux/sysctl.h> 60#include <linux/syscalls.h> 61#include <linux/times.h> 62#include <linux/tsacct_kern.h> 63#include <linux/kprobes.h> 64#include <linux/delayacct.h> 65#include <linux/unistd.h> 66#include <linux/pagemap.h> 67#include <linux/hrtimer.h> 68#include <linux/tick.h> 69#include <linux/debugfs.h> 70#include <linux/ctype.h> 71#include <linux/ftrace.h> 72#include <linux/slab.h> 73#include <linux/init_task.h> 74#include <linux/binfmts.h> 75#include <linux/context_tracking.h> 76 77#include <asm/switch_to.h> 78#include <asm/tlb.h> 79#include <asm/irq_regs.h> 80#include <asm/mutex.h> 81#ifdef CONFIG_PARAVIRT 82#include <asm/paravirt.h> 83#endif 84 85#include "sched.h" 86#include "../workqueue_internal.h" 87#include "../smpboot.h" 88 89#define CREATE_TRACE_POINTS 90#include <trace/events/sched.h> 91 92void start_bandwidth_timer(struct hrtimer *period_timer, ktime_t period) 93{ 94 unsigned long delta; 95 ktime_t soft, hard, now; 96 97 for (;;) { 98 if (hrtimer_active(period_timer)) 99 break; 100 101 now = hrtimer_cb_get_time(period_timer); 102 hrtimer_forward(period_timer, now, period); 103 104 soft = hrtimer_get_softexpires(period_timer); 105 hard = hrtimer_get_expires(period_timer); 106 delta = ktime_to_ns(ktime_sub(hard, soft)); 107 __hrtimer_start_range_ns(period_timer, soft, delta, 108 HRTIMER_MODE_ABS_PINNED, 0); 109 } 110} 111 112DEFINE_MUTEX(sched_domains_mutex); 113DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); 114 115static void update_rq_clock_task(struct rq *rq, s64 delta); 116 117void update_rq_clock(struct rq *rq) 118{ 119 s64 delta; 120 121 if (rq->skip_clock_update > 0) 122 return; 123 124 delta = sched_clock_cpu(cpu_of(rq)) - rq->clock; 125 rq->clock += delta; 126 update_rq_clock_task(rq, delta); 127} 128 129/* 130 * Debugging: various feature bits 131 */ 132 133#define SCHED_FEAT(name, enabled) \ 134 (1UL << __SCHED_FEAT_##name) * enabled | 135 136const_debug unsigned int sysctl_sched_features = 137#include "features.h" 138 0; 139 140#undef SCHED_FEAT 141 142#ifdef CONFIG_SCHED_DEBUG 143#define SCHED_FEAT(name, enabled) \ 144 #name , 145 146static const char * const sched_feat_names[] = { 147#include "features.h" 148}; 149 150#undef SCHED_FEAT 151 152static int sched_feat_show(struct seq_file *m, void *v) 153{ 154 int i; 155 156 for (i = 0; i < __SCHED_FEAT_NR; i++) { 157 if (!(sysctl_sched_features & (1UL << i))) 158 seq_puts(m, "NO_"); 159 seq_printf(m, "%s ", sched_feat_names[i]); 160 } 161 seq_puts(m, "\n"); 162 163 return 0; 164} 165 166#ifdef HAVE_JUMP_LABEL 167 168#define jump_label_key__true STATIC_KEY_INIT_TRUE 169#define jump_label_key__false STATIC_KEY_INIT_FALSE 170 171#define SCHED_FEAT(name, enabled) \ 172 jump_label_key__##enabled , 173 174struct static_key sched_feat_keys[__SCHED_FEAT_NR] = { 175#include "features.h" 176}; 177 178#undef SCHED_FEAT 179 180static void sched_feat_disable(int i) 181{ 182 if (static_key_enabled(&sched_feat_keys[i])) 183 static_key_slow_dec(&sched_feat_keys[i]); 184} 185 186static void sched_feat_enable(int i) 187{ 188 if (!static_key_enabled(&sched_feat_keys[i])) 189 static_key_slow_inc(&sched_feat_keys[i]); 190} 191#else 192static void sched_feat_disable(int i) { }; 193static void sched_feat_enable(int i) { }; 194#endif /* HAVE_JUMP_LABEL */ 195 196static int sched_feat_set(char *cmp) 197{ 198 int i; 199 int neg = 0; 200 201 if (strncmp(cmp, "NO_", 3) == 0) { 202 neg = 1; 203 cmp += 3; 204 } 205 206 for (i = 0; i < __SCHED_FEAT_NR; i++) { 207 if (strcmp(cmp, sched_feat_names[i]) == 0) { 208 if (neg) { 209 sysctl_sched_features &= ~(1UL << i); 210 sched_feat_disable(i); 211 } else { 212 sysctl_sched_features |= (1UL << i); 213 sched_feat_enable(i); 214 } 215 break; 216 } 217 } 218 219 return i; 220} 221 222static ssize_t 223sched_feat_write(struct file *filp, const char __user *ubuf, 224 size_t cnt, loff_t *ppos) 225{ 226 char buf[64]; 227 char *cmp; 228 int i; 229 230 if (cnt > 63) 231 cnt = 63; 232 233 if (copy_from_user(&buf, ubuf, cnt)) 234 return -EFAULT; 235 236 buf[cnt] = 0; 237 cmp = strstrip(buf); 238 239 i = sched_feat_set(cmp); 240 if (i == __SCHED_FEAT_NR) 241 return -EINVAL; 242 243 *ppos += cnt; 244 245 return cnt; 246} 247 248static int sched_feat_open(struct inode *inode, struct file *filp) 249{ 250 return single_open(filp, sched_feat_show, NULL); 251} 252 253static const struct file_operations sched_feat_fops = { 254 .open = sched_feat_open, 255 .write = sched_feat_write, 256 .read = seq_read, 257 .llseek = seq_lseek, 258 .release = single_release, 259}; 260 261static __init int sched_init_debug(void) 262{ 263 debugfs_create_file("sched_features", 0644, NULL, NULL, 264 &sched_feat_fops); 265 266 return 0; 267} 268late_initcall(sched_init_debug); 269#endif /* CONFIG_SCHED_DEBUG */ 270 271/* 272 * Number of tasks to iterate in a single balance run. 273 * Limited because this is done with IRQs disabled. 274 */ 275const_debug unsigned int sysctl_sched_nr_migrate = 32; 276 277/* 278 * period over which we average the RT time consumption, measured 279 * in ms. 280 * 281 * default: 1s 282 */ 283const_debug unsigned int sysctl_sched_time_avg = MSEC_PER_SEC; 284 285/* 286 * period over which we measure -rt task cpu usage in us. 287 * default: 1s 288 */ 289unsigned int sysctl_sched_rt_period = 1000000; 290 291__read_mostly int scheduler_running; 292 293/* 294 * part of the period that we allow rt tasks to run in us. 295 * default: 0.95s 296 */ 297int sysctl_sched_rt_runtime = 950000; 298 299/* 300 * Maximum bandwidth available for all -deadline tasks and groups 301 * (if group scheduling is configured) on each CPU. 302 * 303 * default: 5% 304 */ 305unsigned int sysctl_sched_dl_period = 1000000; 306int sysctl_sched_dl_runtime = 50000; 307 308 309 310/* 311 * __task_rq_lock - lock the rq @p resides on. 312 */ 313static inline struct rq *__task_rq_lock(struct task_struct *p) 314 __acquires(rq->lock) 315{ 316 struct rq *rq; 317 318 lockdep_assert_held(&p->pi_lock); 319 320 for (;;) { 321 rq = task_rq(p); 322 raw_spin_lock(&rq->lock); 323 if (likely(rq == task_rq(p))) 324 return rq; 325 raw_spin_unlock(&rq->lock); 326 } 327} 328 329/* 330 * task_rq_lock - lock p->pi_lock and lock the rq @p resides on. 331 */ 332static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags) 333 __acquires(p->pi_lock) 334 __acquires(rq->lock) 335{ 336 struct rq *rq; 337 338 for (;;) { 339 raw_spin_lock_irqsave(&p->pi_lock, *flags); 340 rq = task_rq(p); 341 raw_spin_lock(&rq->lock); 342 if (likely(rq == task_rq(p))) 343 return rq; 344 raw_spin_unlock(&rq->lock); 345 raw_spin_unlock_irqrestore(&p->pi_lock, *flags); 346 } 347} 348 349static void __task_rq_unlock(struct rq *rq) 350 __releases(rq->lock) 351{ 352 raw_spin_unlock(&rq->lock); 353} 354 355static inline void 356task_rq_unlock(struct rq *rq, struct task_struct *p, unsigned long *flags) 357 __releases(rq->lock) 358 __releases(p->pi_lock) 359{ 360 raw_spin_unlock(&rq->lock); 361 raw_spin_unlock_irqrestore(&p->pi_lock, *flags); 362} 363 364/* 365 * this_rq_lock - lock this runqueue and disable interrupts. 366 */ 367static struct rq *this_rq_lock(void) 368 __acquires(rq->lock) 369{ 370 struct rq *rq; 371 372 local_irq_disable(); 373 rq = this_rq(); 374 raw_spin_lock(&rq->lock); 375 376 return rq; 377} 378 379#ifdef CONFIG_SCHED_HRTICK 380/* 381 * Use HR-timers to deliver accurate preemption points. 382 */ 383 384static void hrtick_clear(struct rq *rq) 385{ 386 if (hrtimer_active(&rq->hrtick_timer)) 387 hrtimer_cancel(&rq->hrtick_timer); 388} 389 390/* 391 * High-resolution timer tick. 392 * Runs from hardirq context with interrupts disabled. 393 */ 394static enum hrtimer_restart hrtick(struct hrtimer *timer) 395{ 396 struct rq *rq = container_of(timer, struct rq, hrtick_timer); 397 398 WARN_ON_ONCE(cpu_of(rq) != smp_processor_id()); 399 400 raw_spin_lock(&rq->lock); 401 update_rq_clock(rq); 402 rq->curr->sched_class->task_tick(rq, rq->curr, 1); 403 raw_spin_unlock(&rq->lock); 404 405 return HRTIMER_NORESTART; 406} 407 408#ifdef CONFIG_SMP 409 410static int __hrtick_restart(struct rq *rq) 411{ 412 struct hrtimer *timer = &rq->hrtick_timer; 413 ktime_t time = hrtimer_get_softexpires(timer); 414 415 return __hrtimer_start_range_ns(timer, time, 0, HRTIMER_MODE_ABS_PINNED, 0); 416} 417 418/* 419 * called from hardirq (IPI) context 420 */ 421static void __hrtick_start(void *arg) 422{ 423 struct rq *rq = arg; 424 425 raw_spin_lock(&rq->lock); 426 __hrtick_restart(rq); 427 rq->hrtick_csd_pending = 0; 428 raw_spin_unlock(&rq->lock); 429} 430 431/* 432 * Called to set the hrtick timer state. 433 * 434 * called with rq->lock held and irqs disabled 435 */ 436void hrtick_start(struct rq *rq, u64 delay) 437{ 438 struct hrtimer *timer = &rq->hrtick_timer; 439 ktime_t time = ktime_add_ns(timer->base->get_time(), delay); 440 441 hrtimer_set_expires(timer, time); 442 443 if (rq == this_rq()) { 444 __hrtick_restart(rq); 445 } else if (!rq->hrtick_csd_pending) { 446 __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd, 0); 447 rq->hrtick_csd_pending = 1; 448 } 449} 450 451static int 452hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu) 453{ 454 int cpu = (int)(long)hcpu; 455 456 switch (action) { 457 case CPU_UP_CANCELED: 458 case CPU_UP_CANCELED_FROZEN: 459 case CPU_DOWN_PREPARE: 460 case CPU_DOWN_PREPARE_FROZEN: 461 case CPU_DEAD: 462 case CPU_DEAD_FROZEN: 463 hrtick_clear(cpu_rq(cpu)); 464 return NOTIFY_OK; 465 } 466 467 return NOTIFY_DONE; 468} 469 470static __init void init_hrtick(void) 471{ 472 hotcpu_notifier(hotplug_hrtick, 0); 473} 474#else 475/* 476 * Called to set the hrtick timer state. 477 * 478 * called with rq->lock held and irqs disabled 479 */ 480void hrtick_start(struct rq *rq, u64 delay) 481{ 482 __hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0, 483 HRTIMER_MODE_REL_PINNED, 0); 484} 485 486static inline void init_hrtick(void) 487{ 488} 489#endif /* CONFIG_SMP */ 490 491static void init_rq_hrtick(struct rq *rq) 492{ 493#ifdef CONFIG_SMP 494 rq->hrtick_csd_pending = 0; 495 496 rq->hrtick_csd.flags = 0; 497 rq->hrtick_csd.func = __hrtick_start; 498 rq->hrtick_csd.info = rq; 499#endif 500 501 hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 502 rq->hrtick_timer.function = hrtick; 503} 504#else /* CONFIG_SCHED_HRTICK */ 505static inline void hrtick_clear(struct rq *rq) 506{ 507} 508 509static inline void init_rq_hrtick(struct rq *rq) 510{ 511} 512 513static inline void init_hrtick(void) 514{ 515} 516#endif /* CONFIG_SCHED_HRTICK */ 517 518/* 519 * resched_task - mark a task 'to be rescheduled now'. 520 * 521 * On UP this means the setting of the need_resched flag, on SMP it 522 * might also involve a cross-CPU call to trigger the scheduler on 523 * the target CPU. 524 */ 525void resched_task(struct task_struct *p) 526{ 527 int cpu; 528 529 lockdep_assert_held(&task_rq(p)->lock); 530 531 if (test_tsk_need_resched(p)) 532 return; 533 534 set_tsk_need_resched(p); 535 536 cpu = task_cpu(p); 537 if (cpu == smp_processor_id()) { 538 set_preempt_need_resched(); 539 return; 540 } 541 542 /* NEED_RESCHED must be visible before we test polling */ 543 smp_mb(); 544 if (!tsk_is_polling(p)) 545 smp_send_reschedule(cpu); 546} 547 548void resched_cpu(int cpu) 549{ 550 struct rq *rq = cpu_rq(cpu); 551 unsigned long flags; 552 553 if (!raw_spin_trylock_irqsave(&rq->lock, flags)) 554 return; 555 resched_task(cpu_curr(cpu)); 556 raw_spin_unlock_irqrestore(&rq->lock, flags); 557} 558 559#ifdef CONFIG_SMP 560#ifdef CONFIG_NO_HZ_COMMON 561/* 562 * In the semi idle case, use the nearest busy cpu for migrating timers 563 * from an idle cpu. This is good for power-savings. 564 * 565 * We don't do similar optimization for completely idle system, as 566 * selecting an idle cpu will add more delays to the timers than intended 567 * (as that cpu's timer base may not be uptodate wrt jiffies etc). 568 */ 569int get_nohz_timer_target(void) 570{ 571 int cpu = smp_processor_id(); 572 int i; 573 struct sched_domain *sd; 574 575 rcu_read_lock(); 576 for_each_domain(cpu, sd) { 577 for_each_cpu(i, sched_domain_span(sd)) { 578 if (!idle_cpu(i)) { 579 cpu = i; 580 goto unlock; 581 } 582 } 583 } 584unlock: 585 rcu_read_unlock(); 586 return cpu; 587} 588/* 589 * When add_timer_on() enqueues a timer into the timer wheel of an 590 * idle CPU then this timer might expire before the next timer event 591 * which is scheduled to wake up that CPU. In case of a completely 592 * idle system the next event might even be infinite time into the 593 * future. wake_up_idle_cpu() ensures that the CPU is woken up and 594 * leaves the inner idle loop so the newly added timer is taken into 595 * account when the CPU goes back to idle and evaluates the timer 596 * wheel for the next timer event. 597 */ 598static void wake_up_idle_cpu(int cpu) 599{ 600 struct rq *rq = cpu_rq(cpu); 601 602 if (cpu == smp_processor_id()) 603 return; 604 605 /* 606 * This is safe, as this function is called with the timer 607 * wheel base lock of (cpu) held. When the CPU is on the way 608 * to idle and has not yet set rq->curr to idle then it will 609 * be serialized on the timer wheel base lock and take the new 610 * timer into account automatically. 611 */ 612 if (rq->curr != rq->idle) 613 return; 614 615 /* 616 * We can set TIF_RESCHED on the idle task of the other CPU 617 * lockless. The worst case is that the other CPU runs the 618 * idle task through an additional NOOP schedule() 619 */ 620 set_tsk_need_resched(rq->idle); 621 622 /* NEED_RESCHED must be visible before we test polling */ 623 smp_mb(); 624 if (!tsk_is_polling(rq->idle)) 625 smp_send_reschedule(cpu); 626} 627 628static bool wake_up_full_nohz_cpu(int cpu) 629{ 630 if (tick_nohz_full_cpu(cpu)) { 631 if (cpu != smp_processor_id() || 632 tick_nohz_tick_stopped()) 633 smp_send_reschedule(cpu); 634 return true; 635 } 636 637 return false; 638} 639 640void wake_up_nohz_cpu(int cpu) 641{ 642 if (!wake_up_full_nohz_cpu(cpu)) 643 wake_up_idle_cpu(cpu); 644} 645 646static inline bool got_nohz_idle_kick(void) 647{ 648 int cpu = smp_processor_id(); 649 650 if (!test_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu))) 651 return false; 652 653 if (idle_cpu(cpu) && !need_resched()) 654 return true; 655 656 /* 657 * We can't run Idle Load Balance on this CPU for this time so we 658 * cancel it and clear NOHZ_BALANCE_KICK 659 */ 660 clear_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu)); 661 return false; 662} 663 664#else /* CONFIG_NO_HZ_COMMON */ 665 666static inline bool got_nohz_idle_kick(void) 667{ 668 return false; 669} 670 671#endif /* CONFIG_NO_HZ_COMMON */ 672 673#ifdef CONFIG_NO_HZ_FULL 674bool sched_can_stop_tick(void) 675{ 676 struct rq *rq; 677 678 rq = this_rq(); 679 680 /* Make sure rq->nr_running update is visible after the IPI */ 681 smp_rmb(); 682 683 /* More than one running task need preemption */ 684 if (rq->nr_running > 1) 685 return false; 686 687 return true; 688} 689#endif /* CONFIG_NO_HZ_FULL */ 690 691void sched_avg_update(struct rq *rq) 692{ 693 s64 period = sched_avg_period(); 694 695 while ((s64)(rq_clock(rq) - rq->age_stamp) > period) { 696 /* 697 * Inline assembly required to prevent the compiler 698 * optimising this loop into a divmod call. 699 * See __iter_div_u64_rem() for another example of this. 700 */ 701 asm("" : "+rm" (rq->age_stamp)); 702 rq->age_stamp += period; 703 rq->rt_avg /= 2; 704 } 705} 706 707#endif /* CONFIG_SMP */ 708 709#if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \ 710 (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH))) 711/* 712 * Iterate task_group tree rooted at *from, calling @down when first entering a 713 * node and @up when leaving it for the final time. 714 * 715 * Caller must hold rcu_lock or sufficient equivalent. 716 */ 717int walk_tg_tree_from(struct task_group *from, 718 tg_visitor down, tg_visitor up, void *data) 719{ 720 struct task_group *parent, *child; 721 int ret; 722 723 parent = from; 724 725down: 726 ret = (*down)(parent, data); 727 if (ret) 728 goto out; 729 list_for_each_entry_rcu(child, &parent->children, siblings) { 730 parent = child; 731 goto down; 732 733up: 734 continue; 735 } 736 ret = (*up)(parent, data); 737 if (ret || parent == from) 738 goto out; 739 740 child = parent; 741 parent = parent->parent; 742 if (parent) 743 goto up; 744out: 745 return ret; 746} 747 748int tg_nop(struct task_group *tg, void *data) 749{ 750 return 0; 751} 752#endif 753 754static void set_load_weight(struct task_struct *p) 755{ 756 int prio = p->static_prio - MAX_RT_PRIO; 757 struct load_weight *load = &p->se.load; 758 759 /* 760 * SCHED_IDLE tasks get minimal weight: 761 */ 762 if (p->policy == SCHED_IDLE) { 763 load->weight = scale_load(WEIGHT_IDLEPRIO); 764 load->inv_weight = WMULT_IDLEPRIO; 765 return; 766 } 767 768 load->weight = scale_load(prio_to_weight[prio]); 769 load->inv_weight = prio_to_wmult[prio]; 770} 771 772static void enqueue_task(struct rq *rq, struct task_struct *p, int flags) 773{ 774 update_rq_clock(rq); 775 sched_info_queued(rq, p); 776 p->sched_class->enqueue_task(rq, p, flags); 777} 778 779static void dequeue_task(struct rq *rq, struct task_struct *p, int flags) 780{ 781 update_rq_clock(rq); 782 sched_info_dequeued(rq, p); 783 p->sched_class->dequeue_task(rq, p, flags); 784} 785 786void activate_task(struct rq *rq, struct task_struct *p, int flags) 787{ 788 if (task_contributes_to_load(p)) 789 rq->nr_uninterruptible--; 790 791 enqueue_task(rq, p, flags); 792} 793 794void deactivate_task(struct rq *rq, struct task_struct *p, int flags) 795{ 796 if (task_contributes_to_load(p)) 797 rq->nr_uninterruptible++; 798 799 dequeue_task(rq, p, flags); 800} 801 802static void update_rq_clock_task(struct rq *rq, s64 delta) 803{ 804/* 805 * In theory, the compile should just see 0 here, and optimize out the call 806 * to sched_rt_avg_update. But I don't trust it... 807 */ 808#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) 809 s64 steal = 0, irq_delta = 0; 810#endif 811#ifdef CONFIG_IRQ_TIME_ACCOUNTING 812 irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time; 813 814 /* 815 * Since irq_time is only updated on {soft,}irq_exit, we might run into 816 * this case when a previous update_rq_clock() happened inside a 817 * {soft,}irq region. 818 * 819 * When this happens, we stop ->clock_task and only update the 820 * prev_irq_time stamp to account for the part that fit, so that a next 821 * update will consume the rest. This ensures ->clock_task is 822 * monotonic. 823 * 824 * It does however cause some slight miss-attribution of {soft,}irq 825 * time, a more accurate solution would be to update the irq_time using 826 * the current rq->clock timestamp, except that would require using 827 * atomic ops. 828 */ 829 if (irq_delta > delta) 830 irq_delta = delta; 831 832 rq->prev_irq_time += irq_delta; 833 delta -= irq_delta; 834#endif 835#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING 836 if (static_key_false((¶virt_steal_rq_enabled))) { 837 u64 st; 838 839 steal = paravirt_steal_clock(cpu_of(rq)); 840 steal -= rq->prev_steal_time_rq; 841 842 if (unlikely(steal > delta)) 843 steal = delta; 844 845 st = steal_ticks(steal); 846 steal = st * TICK_NSEC; 847 848 rq->prev_steal_time_rq += steal; 849 850 delta -= steal; 851 } 852#endif 853 854 rq->clock_task += delta; 855 856#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) 857 if ((irq_delta + steal) && sched_feat(NONTASK_POWER)) 858 sched_rt_avg_update(rq, irq_delta + steal); 859#endif 860} 861 862void sched_set_stop_task(int cpu, struct task_struct *stop) 863{ 864 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 }; 865 struct task_struct *old_stop = cpu_rq(cpu)->stop; 866 867 if (stop) { 868 /* 869 * Make it appear like a SCHED_FIFO task, its something 870 * userspace knows about and won't get confused about. 871 * 872 * Also, it will make PI more or less work without too 873 * much confusion -- but then, stop work should not 874 * rely on PI working anyway. 875 */ 876 sched_setscheduler_nocheck(stop, SCHED_FIFO, ¶m); 877 878 stop->sched_class = &stop_sched_class; 879 } 880 881 cpu_rq(cpu)->stop = stop; 882 883 if (old_stop) { 884 /* 885 * Reset it back to a normal scheduling class so that 886 * it can die in pieces. 887 */ 888 old_stop->sched_class = &rt_sched_class; 889 } 890} 891 892/* 893 * __normal_prio - return the priority that is based on the static prio 894 */ 895static inline int __normal_prio(struct task_struct *p) 896{ 897 return p->static_prio; 898} 899 900/* 901 * Calculate the expected normal priority: i.e. priority 902 * without taking RT-inheritance into account. Might be 903 * boosted by interactivity modifiers. Changes upon fork, 904 * setprio syscalls, and whenever the interactivity 905 * estimator recalculates. 906 */ 907static inline int normal_prio(struct task_struct *p) 908{ 909 int prio; 910 911 if (task_has_dl_policy(p)) 912 prio = MAX_DL_PRIO-1; 913 else if (task_has_rt_policy(p)) 914 prio = MAX_RT_PRIO-1 - p->rt_priority; 915 else 916 prio = __normal_prio(p); 917 return prio; 918} 919 920/* 921 * Calculate the current priority, i.e. the priority 922 * taken into account by the scheduler. This value might 923 * be boosted by RT tasks, or might be boosted by 924 * interactivity modifiers. Will be RT if the task got 925 * RT-boosted. If not then it returns p->normal_prio. 926 */ 927static int effective_prio(struct task_struct *p) 928{ 929 p->normal_prio = normal_prio(p); 930 /* 931 * If we are RT tasks or we were boosted to RT priority, 932 * keep the priority unchanged. Otherwise, update priority 933 * to the normal priority: 934 */ 935 if (!rt_prio(p->prio)) 936 return p->normal_prio; 937 return p->prio; 938} 939 940/** 941 * task_curr - is this task currently executing on a CPU? 942 * @p: the task in question. 943 * 944 * Return: 1 if the task is currently executing. 0 otherwise. 945 */ 946inline int task_curr(const struct task_struct *p) 947{ 948 return cpu_curr(task_cpu(p)) == p; 949} 950 951static inline void check_class_changed(struct rq *rq, struct task_struct *p, 952 const struct sched_class *prev_class, 953 int oldprio) 954{ 955 if (prev_class != p->sched_class) { 956 if (prev_class->switched_from) 957 prev_class->switched_from(rq, p); 958 p->sched_class->switched_to(rq, p); 959 } else if (oldprio != p->prio || dl_task(p)) 960 p->sched_class->prio_changed(rq, p, oldprio); 961} 962 963void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags) 964{ 965 const struct sched_class *class; 966 967 if (p->sched_class == rq->curr->sched_class) { 968 rq->curr->sched_class->check_preempt_curr(rq, p, flags); 969 } else { 970 for_each_class(class) { 971 if (class == rq->curr->sched_class) 972 break; 973 if (class == p->sched_class) { 974 resched_task(rq->curr); 975 break; 976 } 977 } 978 } 979 980 /* 981 * A queue event has occurred, and we're going to schedule. In 982 * this case, we can save a useless back to back clock update. 983 */ 984 if (rq->curr->on_rq && test_tsk_need_resched(rq->curr)) 985 rq->skip_clock_update = 1; 986} 987 988#ifdef CONFIG_SMP 989void set_task_cpu(struct task_struct *p, unsigned int new_cpu) 990{ 991#ifdef CONFIG_SCHED_DEBUG 992 /* 993 * We should never call set_task_cpu() on a blocked task, 994 * ttwu() will sort out the placement. 995 */ 996 WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING && 997 !(task_preempt_count(p) & PREEMPT_ACTIVE)); 998 999#ifdef CONFIG_LOCKDEP 1000 /* 1001 * The caller should hold either p->pi_lock or rq->lock, when changing 1002 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks. 1003 * 1004 * sched_move_task() holds both and thus holding either pins the cgroup, 1005 * see task_group(). 1006 * 1007 * Furthermore, all task_rq users should acquire both locks, see 1008 * task_rq_lock(). 1009 */ 1010 WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) || 1011 lockdep_is_held(&task_rq(p)->lock))); 1012#endif 1013#endif 1014 1015 trace_sched_migrate_task(p, new_cpu); 1016 1017 if (task_cpu(p) != new_cpu) { 1018 if (p->sched_class->migrate_task_rq) 1019 p->sched_class->migrate_task_rq(p, new_cpu); 1020 p->se.nr_migrations++; 1021 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, 1, NULL, 0); 1022 } 1023 1024 __set_task_cpu(p, new_cpu); 1025} 1026 1027static void __migrate_swap_task(struct task_struct *p, int cpu) 1028{ 1029 if (p->on_rq) { 1030 struct rq *src_rq, *dst_rq; 1031 1032 src_rq = task_rq(p); 1033 dst_rq = cpu_rq(cpu); 1034 1035 deactivate_task(src_rq, p, 0); 1036 set_task_cpu(p, cpu); 1037 activate_task(dst_rq, p, 0); 1038 check_preempt_curr(dst_rq, p, 0); 1039 } else { 1040 /* 1041 * Task isn't running anymore; make it appear like we migrated 1042 * it before it went to sleep. This means on wakeup we make the 1043 * previous cpu our targer instead of where it really is. 1044 */ 1045 p->wake_cpu = cpu; 1046 } 1047} 1048 1049struct migration_swap_arg { 1050 struct task_struct *src_task, *dst_task; 1051 int src_cpu, dst_cpu; 1052}; 1053 1054static int migrate_swap_stop(void *data) 1055{ 1056 struct migration_swap_arg *arg = data; 1057 struct rq *src_rq, *dst_rq; 1058 int ret = -EAGAIN; 1059 1060 src_rq = cpu_rq(arg->src_cpu); 1061 dst_rq = cpu_rq(arg->dst_cpu); 1062 1063 double_raw_lock(&arg->src_task->pi_lock, 1064 &arg->dst_task->pi_lock); 1065 double_rq_lock(src_rq, dst_rq); 1066 if (task_cpu(arg->dst_task) != arg->dst_cpu) 1067 goto unlock; 1068 1069 if (task_cpu(arg->src_task) != arg->src_cpu) 1070 goto unlock; 1071 1072 if (!cpumask_test_cpu(arg->dst_cpu, tsk_cpus_allowed(arg->src_task))) 1073 goto unlock; 1074 1075 if (!cpumask_test_cpu(arg->src_cpu, tsk_cpus_allowed(arg->dst_task))) 1076 goto unlock; 1077 1078 __migrate_swap_task(arg->src_task, arg->dst_cpu); 1079 __migrate_swap_task(arg->dst_task, arg->src_cpu); 1080 1081 ret = 0; 1082 1083unlock: 1084 double_rq_unlock(src_rq, dst_rq); 1085 raw_spin_unlock(&arg->dst_task->pi_lock); 1086 raw_spin_unlock(&arg->src_task->pi_lock); 1087 1088 return ret; 1089} 1090 1091/* 1092 * Cross migrate two tasks 1093 */ 1094int migrate_swap(struct task_struct *cur, struct task_struct *p) 1095{ 1096 struct migration_swap_arg arg; 1097 int ret = -EINVAL; 1098 1099 arg = (struct migration_swap_arg){ 1100 .src_task = cur, 1101 .src_cpu = task_cpu(cur), 1102 .dst_task = p, 1103 .dst_cpu = task_cpu(p), 1104 }; 1105 1106 if (arg.src_cpu == arg.dst_cpu) 1107 goto out; 1108 1109 /* 1110 * These three tests are all lockless; this is OK since all of them 1111 * will be re-checked with proper locks held further down the line. 1112 */ 1113 if (!cpu_active(arg.src_cpu) || !cpu_active(arg.dst_cpu)) 1114 goto out; 1115 1116 if (!cpumask_test_cpu(arg.dst_cpu, tsk_cpus_allowed(arg.src_task))) 1117 goto out; 1118 1119 if (!cpumask_test_cpu(arg.src_cpu, tsk_cpus_allowed(arg.dst_task))) 1120 goto out; 1121 1122 ret = stop_two_cpus(arg.dst_cpu, arg.src_cpu, migrate_swap_stop, &arg); 1123 1124out: 1125 return ret; 1126} 1127 1128struct migration_arg { 1129 struct task_struct *task; 1130 int dest_cpu; 1131}; 1132 1133static int migration_cpu_stop(void *data); 1134 1135/* 1136 * wait_task_inactive - wait for a thread to unschedule. 1137 * 1138 * If @match_state is nonzero, it's the @p->state value just checked and 1139 * not expected to change. If it changes, i.e. @p might have woken up, 1140 * then return zero. When we succeed in waiting for @p to be off its CPU, 1141 * we return a positive number (its total switch count). If a second call 1142 * a short while later returns the same number, the caller can be sure that 1143 * @p has remained unscheduled the whole time. 1144 * 1145 * The caller must ensure that the task *will* unschedule sometime soon, 1146 * else this function might spin for a *long* time. This function can't 1147 * be called with interrupts off, or it may introduce deadlock with 1148 * smp_call_function() if an IPI is sent by the same process we are 1149 * waiting to become inactive. 1150 */ 1151unsigned long wait_task_inactive(struct task_struct *p, long match_state) 1152{ 1153 unsigned long flags; 1154 int running, on_rq; 1155 unsigned long ncsw; 1156 struct rq *rq; 1157 1158 for (;;) { 1159 /* 1160 * We do the initial early heuristics without holding 1161 * any task-queue locks at all. We'll only try to get 1162 * the runqueue lock when things look like they will 1163 * work out! 1164 */ 1165 rq = task_rq(p); 1166 1167 /* 1168 * If the task is actively running on another CPU 1169 * still, just relax and busy-wait without holding 1170 * any locks. 1171 * 1172 * NOTE! Since we don't hold any locks, it's not 1173 * even sure that "rq" stays as the right runqueue! 1174 * But we don't care, since "task_running()" will 1175 * return false if the runqueue has changed and p 1176 * is actually now running somewhere else! 1177 */ 1178 while (task_running(rq, p)) { 1179 if (match_state && unlikely(p->state != match_state)) 1180 return 0; 1181 cpu_relax(); 1182 } 1183 1184 /* 1185 * Ok, time to look more closely! We need the rq 1186 * lock now, to be *sure*. If we're wrong, we'll 1187 * just go back and repeat. 1188 */ 1189 rq = task_rq_lock(p, &flags); 1190 trace_sched_wait_task(p); 1191 running = task_running(rq, p); 1192 on_rq = p->on_rq; 1193 ncsw = 0; 1194 if (!match_state || p->state == match_state) 1195 ncsw = p->nvcsw | LONG_MIN; /* sets MSB */ 1196 task_rq_unlock(rq, p, &flags); 1197 1198 /* 1199 * If it changed from the expected state, bail out now. 1200 */ 1201 if (unlikely(!ncsw)) 1202 break; 1203 1204 /* 1205 * Was it really running after all now that we 1206 * checked with the proper locks actually held? 1207 * 1208 * Oops. Go back and try again.. 1209 */ 1210 if (unlikely(running)) { 1211 cpu_relax(); 1212 continue; 1213 } 1214 1215 /* 1216 * It's not enough that it's not actively running, 1217 * it must be off the runqueue _entirely_, and not 1218 * preempted! 1219 * 1220 * So if it was still runnable (but just not actively 1221 * running right now), it's preempted, and we should 1222 * yield - it could be a while. 1223 */ 1224 if (unlikely(on_rq)) { 1225 ktime_t to = ktime_set(0, NSEC_PER_SEC/HZ); 1226 1227 set_current_state(TASK_UNINTERRUPTIBLE); 1228 schedule_hrtimeout(&to, HRTIMER_MODE_REL); 1229 continue; 1230 } 1231 1232 /* 1233 * Ahh, all good. It wasn't running, and it wasn't 1234 * runnable, which means that it will never become 1235 * running in the future either. We're all done! 1236 */ 1237 break; 1238 } 1239 1240 return ncsw; 1241} 1242 1243/*** 1244 * kick_process - kick a running thread to enter/exit the kernel 1245 * @p: the to-be-kicked thread 1246 * 1247 * Cause a process which is running on another CPU to enter 1248 * kernel-mode, without any delay. (to get signals handled.) 1249 * 1250 * NOTE: this function doesn't have to take the runqueue lock, 1251 * because all it wants to ensure is that the remote task enters 1252 * the kernel. If the IPI races and the task has been migrated 1253 * to another CPU then no harm is done and the purpose has been 1254 * achieved as well. 1255 */ 1256void kick_process(struct task_struct *p) 1257{ 1258 int cpu; 1259 1260 preempt_disable(); 1261 cpu = task_cpu(p); 1262 if ((cpu != smp_processor_id()) && task_curr(p)) 1263 smp_send_reschedule(cpu); 1264 preempt_enable(); 1265} 1266EXPORT_SYMBOL_GPL(kick_process); 1267#endif /* CONFIG_SMP */ 1268 1269#ifdef CONFIG_SMP 1270/* 1271 * ->cpus_allowed is protected by both rq->lock and p->pi_lock 1272 */ 1273static int select_fallback_rq(int cpu, struct task_struct *p) 1274{ 1275 int nid = cpu_to_node(cpu); 1276 const struct cpumask *nodemask = NULL; 1277 enum { cpuset, possible, fail } state = cpuset; 1278 int dest_cpu; 1279 1280 /* 1281 * If the node that the cpu is on has been offlined, cpu_to_node() 1282 * will return -1. There is no cpu on the node, and we should 1283 * select the cpu on the other node. 1284 */ 1285 if (nid != -1) { 1286 nodemask = cpumask_of_node(nid); 1287 1288 /* Look for allowed, online CPU in same node. */ 1289 for_each_cpu(dest_cpu, nodemask) { 1290 if (!cpu_online(dest_cpu)) 1291 continue; 1292 if (!cpu_active(dest_cpu)) 1293 continue; 1294 if (cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) 1295 return dest_cpu; 1296 } 1297 } 1298 1299 for (;;) { 1300 /* Any allowed, online CPU? */ 1301 for_each_cpu(dest_cpu, tsk_cpus_allowed(p)) { 1302 if (!cpu_online(dest_cpu)) 1303 continue; 1304 if (!cpu_active(dest_cpu)) 1305 continue; 1306 goto out; 1307 } 1308 1309 switch (state) { 1310 case cpuset: 1311 /* No more Mr. Nice Guy. */ 1312 cpuset_cpus_allowed_fallback(p); 1313 state = possible; 1314 break; 1315 1316 case possible: 1317 do_set_cpus_allowed(p, cpu_possible_mask); 1318 state = fail; 1319 break; 1320 1321 case fail: 1322 BUG(); 1323 break; 1324 } 1325 } 1326 1327out: 1328 if (state != cpuset) { 1329 /* 1330 * Don't tell them about moving exiting tasks or 1331 * kernel threads (both mm NULL), since they never 1332 * leave kernel. 1333 */ 1334 if (p->mm && printk_ratelimit()) { 1335 printk_sched("process %d (%s) no longer affine to cpu%d\n", 1336 task_pid_nr(p), p->comm, cpu); 1337 } 1338 } 1339 1340 return dest_cpu; 1341} 1342 1343/* 1344 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable. 1345 */ 1346static inline 1347int select_task_rq(struct task_struct *p, int cpu, int sd_flags, int wake_flags) 1348{ 1349 cpu = p->sched_class->select_task_rq(p, cpu, sd_flags, wake_flags); 1350 1351 /* 1352 * In order not to call set_task_cpu() on a blocking task we need 1353 * to rely on ttwu() to place the task on a valid ->cpus_allowed 1354 * cpu. 1355 * 1356 * Since this is common to all placement strategies, this lives here. 1357 * 1358 * [ this allows ->select_task() to simply return task_cpu(p) and 1359 * not worry about this generic constraint ] 1360 */ 1361 if (unlikely(!cpumask_test_cpu(cpu, tsk_cpus_allowed(p)) || 1362 !cpu_online(cpu))) 1363 cpu = select_fallback_rq(task_cpu(p), p); 1364 1365 return cpu; 1366} 1367 1368static void update_avg(u64 *avg, u64 sample) 1369{ 1370 s64 diff = sample - *avg; 1371 *avg += diff >> 3; 1372} 1373#endif 1374 1375static void 1376ttwu_stat(struct task_struct *p, int cpu, int wake_flags) 1377{ 1378#ifdef CONFIG_SCHEDSTATS 1379 struct rq *rq = this_rq(); 1380 1381#ifdef CONFIG_SMP 1382 int this_cpu = smp_processor_id(); 1383 1384 if (cpu == this_cpu) { 1385 schedstat_inc(rq, ttwu_local); 1386 schedstat_inc(p, se.statistics.nr_wakeups_local); 1387 } else { 1388 struct sched_domain *sd; 1389 1390 schedstat_inc(p, se.statistics.nr_wakeups_remote); 1391 rcu_read_lock(); 1392 for_each_domain(this_cpu, sd) { 1393 if (cpumask_test_cpu(cpu, sched_domain_span(sd))) { 1394 schedstat_inc(sd, ttwu_wake_remote); 1395 break; 1396 } 1397 } 1398 rcu_read_unlock(); 1399 } 1400 1401 if (wake_flags & WF_MIGRATED) 1402 schedstat_inc(p, se.statistics.nr_wakeups_migrate); 1403 1404#endif /* CONFIG_SMP */ 1405 1406 schedstat_inc(rq, ttwu_count); 1407 schedstat_inc(p, se.statistics.nr_wakeups); 1408 1409 if (wake_flags & WF_SYNC) 1410 schedstat_inc(p, se.statistics.nr_wakeups_sync); 1411 1412#endif /* CONFIG_SCHEDSTATS */ 1413} 1414 1415static void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags) 1416{ 1417 activate_task(rq, p, en_flags); 1418 p->on_rq = 1; 1419 1420 /* if a worker is waking up, notify workqueue */ 1421 if (p->flags & PF_WQ_WORKER) 1422 wq_worker_waking_up(p, cpu_of(rq)); 1423} 1424 1425/* 1426 * Mark the task runnable and perform wakeup-preemption. 1427 */ 1428static void 1429ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags) 1430{ 1431 check_preempt_curr(rq, p, wake_flags); 1432 trace_sched_wakeup(p, true); 1433 1434 p->state = TASK_RUNNING; 1435#ifdef CONFIG_SMP 1436 if (p->sched_class->task_woken) 1437 p->sched_class->task_woken(rq, p); 1438 1439 if (rq->idle_stamp) { 1440 u64 delta = rq_clock(rq) - rq->idle_stamp; 1441 u64 max = 2*rq->max_idle_balance_cost; 1442 1443 update_avg(&rq->avg_idle, delta); 1444 1445 if (rq->avg_idle > max) 1446 rq->avg_idle = max; 1447 1448 rq->idle_stamp = 0; 1449 } 1450#endif 1451} 1452 1453static void 1454ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags) 1455{ 1456#ifdef CONFIG_SMP 1457 if (p->sched_contributes_to_load) 1458 rq->nr_uninterruptible--; 1459#endif 1460 1461 ttwu_activate(rq, p, ENQUEUE_WAKEUP | ENQUEUE_WAKING); 1462 ttwu_do_wakeup(rq, p, wake_flags); 1463} 1464 1465/* 1466 * Called in case the task @p isn't fully descheduled from its runqueue, 1467 * in this case we must do a remote wakeup. Its a 'light' wakeup though, 1468 * since all we need to do is flip p->state to TASK_RUNNING, since 1469 * the task is still ->on_rq. 1470 */ 1471static int ttwu_remote(struct task_struct *p, int wake_flags) 1472{ 1473 struct rq *rq; 1474 int ret = 0; 1475 1476 rq = __task_rq_lock(p); 1477 if (p->on_rq) { 1478 /* check_preempt_curr() may use rq clock */ 1479 update_rq_clock(rq); 1480 ttwu_do_wakeup(rq, p, wake_flags); 1481 ret = 1; 1482 } 1483 __task_rq_unlock(rq); 1484 1485 return ret; 1486} 1487 1488#ifdef CONFIG_SMP 1489static void sched_ttwu_pending(void) 1490{ 1491 struct rq *rq = this_rq(); 1492 struct llist_node *llist = llist_del_all(&rq->wake_list); 1493 struct task_struct *p; 1494 1495 raw_spin_lock(&rq->lock); 1496 1497 while (llist) { 1498 p = llist_entry(llist, struct task_struct, wake_entry); 1499 llist = llist_next(llist); 1500 ttwu_do_activate(rq, p, 0); 1501 } 1502 1503 raw_spin_unlock(&rq->lock); 1504} 1505 1506void scheduler_ipi(void) 1507{ 1508 /* 1509 * Fold TIF_NEED_RESCHED into the preempt_count; anybody setting 1510 * TIF_NEED_RESCHED remotely (for the first time) will also send 1511 * this IPI. 1512 */ 1513 if (tif_need_resched()) 1514 set_preempt_need_resched(); 1515 1516 if (llist_empty(&this_rq()->wake_list) 1517 && !tick_nohz_full_cpu(smp_processor_id()) 1518 && !got_nohz_idle_kick()) 1519 return; 1520 1521 /* 1522 * Not all reschedule IPI handlers call irq_enter/irq_exit, since 1523 * traditionally all their work was done from the interrupt return 1524 * path. Now that we actually do some work, we need to make sure 1525 * we do call them. 1526 * 1527 * Some archs already do call them, luckily irq_enter/exit nest 1528 * properly. 1529 * 1530 * Arguably we should visit all archs and update all handlers, 1531 * however a fair share of IPIs are still resched only so this would 1532 * somewhat pessimize the simple resched case. 1533 */ 1534 irq_enter(); 1535 tick_nohz_full_check(); 1536 sched_ttwu_pending(); 1537 1538 /* 1539 * Check if someone kicked us for doing the nohz idle load balance. 1540 */ 1541 if (unlikely(got_nohz_idle_kick())) { 1542 this_rq()->idle_balance = 1; 1543 raise_softirq_irqoff(SCHED_SOFTIRQ); 1544 } 1545 irq_exit(); 1546} 1547 1548static void ttwu_queue_remote(struct task_struct *p, int cpu) 1549{ 1550 if (llist_add(&p->wake_entry, &cpu_rq(cpu)->wake_list)) 1551 smp_send_reschedule(cpu); 1552} 1553 1554bool cpus_share_cache(int this_cpu, int that_cpu) 1555{ 1556 return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu); 1557} 1558#endif /* CONFIG_SMP */ 1559 1560static void ttwu_queue(struct task_struct *p, int cpu) 1561{ 1562 struct rq *rq = cpu_rq(cpu); 1563 1564#if defined(CONFIG_SMP) 1565 if (sched_feat(TTWU_QUEUE) && !cpus_share_cache(smp_processor_id(), cpu)) { 1566 sched_clock_cpu(cpu); /* sync clocks x-cpu */ 1567 ttwu_queue_remote(p, cpu); 1568 return; 1569 } 1570#endif 1571 1572 raw_spin_lock(&rq->lock); 1573 ttwu_do_activate(rq, p, 0); 1574 raw_spin_unlock(&rq->lock); 1575} 1576 1577/** 1578 * try_to_wake_up - wake up a thread 1579 * @p: the thread to be awakened 1580 * @state: the mask of task states that can be woken 1581 * @wake_flags: wake modifier flags (WF_*) 1582 * 1583 * Put it on the run-queue if it's not already there. The "current" 1584 * thread is always on the run-queue (except when the actual 1585 * re-schedule is in progress), and as such you're allowed to do 1586 * the simpler "current->state = TASK_RUNNING" to mark yourself 1587 * runnable without the overhead of this. 1588 * 1589 * Return: %true if @p was woken up, %false if it was already running. 1590 * or @state didn't match @p's state. 1591 */ 1592static int 1593try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) 1594{ 1595 unsigned long flags; 1596 int cpu, success = 0; 1597 1598 /* 1599 * If we are going to wake up a thread waiting for CONDITION we 1600 * need to ensure that CONDITION=1 done by the caller can not be 1601 * reordered with p->state check below. This pairs with mb() in 1602 * set_current_state() the waiting thread does. 1603 */ 1604 smp_mb__before_spinlock(); 1605 raw_spin_lock_irqsave(&p->pi_lock, flags); 1606 if (!(p->state & state)) 1607 goto out; 1608 1609 success = 1; /* we're going to change ->state */ 1610 cpu = task_cpu(p); 1611 1612 if (p->on_rq && ttwu_remote(p, wake_flags)) 1613 goto stat; 1614 1615#ifdef CONFIG_SMP 1616 /* 1617 * If the owning (remote) cpu is still in the middle of schedule() with 1618 * this task as prev, wait until its done referencing the task. 1619 */ 1620 while (p->on_cpu) 1621 cpu_relax(); 1622 /* 1623 * Pairs with the smp_wmb() in finish_lock_switch(). 1624 */ 1625 smp_rmb(); 1626 1627 p->sched_contributes_to_load = !!task_contributes_to_load(p); 1628 p->state = TASK_WAKING; 1629 1630 if (p->sched_class->task_waking) 1631 p->sched_class->task_waking(p); 1632 1633 cpu = select_task_rq(p, p->wake_cpu, SD_BALANCE_WAKE, wake_flags); 1634 if (task_cpu(p) != cpu) { 1635 wake_flags |= WF_MIGRATED; 1636 set_task_cpu(p, cpu); 1637 } 1638#endif /* CONFIG_SMP */ 1639 1640 ttwu_queue(p, cpu); 1641stat: 1642 ttwu_stat(p, cpu, wake_flags); 1643out: 1644 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 1645 1646 return success; 1647} 1648 1649/** 1650 * try_to_wake_up_local - try to wake up a local task with rq lock held 1651 * @p: the thread to be awakened 1652 * 1653 * Put @p on the run-queue if it's not already there. The caller must 1654 * ensure that this_rq() is locked, @p is bound to this_rq() and not 1655 * the current task. 1656 */ 1657static void try_to_wake_up_local(struct task_struct *p) 1658{ 1659 struct rq *rq = task_rq(p); 1660 1661 if (WARN_ON_ONCE(rq != this_rq()) || 1662 WARN_ON_ONCE(p == current)) 1663 return; 1664 1665 lockdep_assert_held(&rq->lock); 1666 1667 if (!raw_spin_trylock(&p->pi_lock)) { 1668 raw_spin_unlock(&rq->lock); 1669 raw_spin_lock(&p->pi_lock); 1670 raw_spin_lock(&rq->lock); 1671 } 1672 1673 if (!(p->state & TASK_NORMAL)) 1674 goto out; 1675 1676 if (!p->on_rq) 1677 ttwu_activate(rq, p, ENQUEUE_WAKEUP); 1678 1679 ttwu_do_wakeup(rq, p, 0); 1680 ttwu_stat(p, smp_processor_id(), 0); 1681out: 1682 raw_spin_unlock(&p->pi_lock); 1683} 1684 1685/** 1686 * wake_up_process - Wake up a specific process 1687 * @p: The process to be woken up. 1688 * 1689 * Attempt to wake up the nominated process and move it to the set of runnable 1690 * processes. 1691 * 1692 * Return: 1 if the process was woken up, 0 if it was already running. 1693 * 1694 * It may be assumed that this function implies a write memory barrier before 1695 * changing the task state if and only if any tasks are woken up. 1696 */ 1697int wake_up_process(struct task_struct *p) 1698{ 1699 WARN_ON(task_is_stopped_or_traced(p)); 1700 return try_to_wake_up(p, TASK_NORMAL, 0); 1701} 1702EXPORT_SYMBOL(wake_up_process); 1703 1704int wake_up_state(struct task_struct *p, unsigned int state) 1705{ 1706 return try_to_wake_up(p, state, 0); 1707} 1708 1709/* 1710 * Perform scheduler related setup for a newly forked process p. 1711 * p is forked by current. 1712 * 1713 * __sched_fork() is basic setup used by init_idle() too: 1714 */ 1715static void __sched_fork(unsigned long clone_flags, struct task_struct *p) 1716{ 1717 p->on_rq = 0; 1718 1719 p->se.on_rq = 0; 1720 p->se.exec_start = 0; 1721 p->se.sum_exec_runtime = 0; 1722 p->se.prev_sum_exec_runtime = 0; 1723 p->se.nr_migrations = 0; 1724 p->se.vruntime = 0; 1725 INIT_LIST_HEAD(&p->se.group_node); 1726 1727#ifdef CONFIG_SCHEDSTATS 1728 memset(&p->se.statistics, 0, sizeof(p->se.statistics)); 1729#endif 1730 1731 RB_CLEAR_NODE(&p->dl.rb_node); 1732 hrtimer_init(&p->dl.dl_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 1733 p->dl.dl_runtime = p->dl.runtime = 0; 1734 p->dl.dl_deadline = p->dl.deadline = 0; 1735 p->dl.dl_period = 0; 1736 p->dl.flags = 0; 1737 1738 INIT_LIST_HEAD(&p->rt.run_list); 1739 1740#ifdef CONFIG_PREEMPT_NOTIFIERS 1741 INIT_HLIST_HEAD(&p->preempt_notifiers); 1742#endif 1743 1744#ifdef CONFIG_NUMA_BALANCING 1745 if (p->mm && atomic_read(&p->mm->mm_users) == 1) { 1746 p->mm->numa_next_scan = jiffies + msecs_to_jiffies(sysctl_numa_balancing_scan_delay); 1747 p->mm->numa_scan_seq = 0; 1748 } 1749 1750 if (clone_flags & CLONE_VM) 1751 p->numa_preferred_nid = current->numa_preferred_nid; 1752 else 1753 p->numa_preferred_nid = -1; 1754 1755 p->node_stamp = 0ULL; 1756 p->numa_scan_seq = p->mm ? p->mm->numa_scan_seq : 0; 1757 p->numa_scan_period = sysctl_numa_balancing_scan_delay; 1758 p->numa_work.next = &p->numa_work; 1759 p->numa_faults = NULL; 1760 p->numa_faults_buffer = NULL; 1761 1762 INIT_LIST_HEAD(&p->numa_entry); 1763 p->numa_group = NULL; 1764#endif /* CONFIG_NUMA_BALANCING */ 1765} 1766 1767#ifdef CONFIG_NUMA_BALANCING 1768#ifdef CONFIG_SCHED_DEBUG 1769void set_numabalancing_state(bool enabled) 1770{ 1771 if (enabled) 1772 sched_feat_set("NUMA"); 1773 else 1774 sched_feat_set("NO_NUMA"); 1775} 1776#else 1777__read_mostly bool numabalancing_enabled; 1778 1779void set_numabalancing_state(bool enabled) 1780{ 1781 numabalancing_enabled = enabled; 1782} 1783#endif /* CONFIG_SCHED_DEBUG */ 1784#endif /* CONFIG_NUMA_BALANCING */ 1785 1786/* 1787 * fork()/clone()-time setup: 1788 */ 1789int sched_fork(unsigned long clone_flags, struct task_struct *p) 1790{ 1791 unsigned long flags; 1792 int cpu = get_cpu(); 1793 1794 __sched_fork(clone_flags, p); 1795 /* 1796 * We mark the process as running here. This guarantees that 1797 * nobody will actually run it, and a signal or other external 1798 * event cannot wake it up and insert it on the runqueue either. 1799 */ 1800 p->state = TASK_RUNNING; 1801 1802 /* 1803 * Make sure we do not leak PI boosting priority to the child. 1804 */ 1805 p->prio = current->normal_prio; 1806 1807 /* 1808 * Revert to default priority/policy on fork if requested. 1809 */ 1810 if (unlikely(p->sched_reset_on_fork)) { 1811 if (task_has_dl_policy(p) || task_has_rt_policy(p)) { 1812 p->policy = SCHED_NORMAL; 1813 p->static_prio = NICE_TO_PRIO(0); 1814 p->rt_priority = 0; 1815 } else if (PRIO_TO_NICE(p->static_prio) < 0) 1816 p->static_prio = NICE_TO_PRIO(0); 1817 1818 p->prio = p->normal_prio = __normal_prio(p); 1819 set_load_weight(p); 1820 1821 /* 1822 * We don't need the reset flag anymore after the fork. It has 1823 * fulfilled its duty: 1824 */ 1825 p->sched_reset_on_fork = 0; 1826 } 1827 1828 if (dl_prio(p->prio)) { 1829 put_cpu(); 1830 return -EAGAIN; 1831 } else if (rt_prio(p->prio)) { 1832 p->sched_class = &rt_sched_class; 1833 } else { 1834 p->sched_class = &fair_sched_class; 1835 } 1836 1837 if (p->sched_class->task_fork) 1838 p->sched_class->task_fork(p); 1839 1840 /* 1841 * The child is not yet in the pid-hash so no cgroup attach races, 1842 * and the cgroup is pinned to this child due to cgroup_fork() 1843 * is ran before sched_fork(). 1844 * 1845 * Silence PROVE_RCU. 1846 */ 1847 raw_spin_lock_irqsave(&p->pi_lock, flags); 1848 set_task_cpu(p, cpu); 1849 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 1850 1851#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) 1852 if (likely(sched_info_on())) 1853 memset(&p->sched_info, 0, sizeof(p->sched_info)); 1854#endif 1855#if defined(CONFIG_SMP) 1856 p->on_cpu = 0; 1857#endif 1858 init_task_preempt_count(p); 1859#ifdef CONFIG_SMP 1860 plist_node_init(&p->pushable_tasks, MAX_PRIO); 1861 RB_CLEAR_NODE(&p->pushable_dl_tasks); 1862#endif 1863 1864 put_cpu(); 1865 return 0; 1866} 1867 1868unsigned long to_ratio(u64 period, u64 runtime) 1869{ 1870 if (runtime == RUNTIME_INF) 1871 return 1ULL << 20; 1872 1873 /* 1874 * Doing this here saves a lot of checks in all 1875 * the calling paths, and returning zero seems 1876 * safe for them anyway. 1877 */ 1878 if (period == 0) 1879 return 0; 1880 1881 return div64_u64(runtime << 20, period); 1882} 1883 1884#ifdef CONFIG_SMP 1885inline struct dl_bw *dl_bw_of(int i) 1886{ 1887 return &cpu_rq(i)->rd->dl_bw; 1888} 1889 1890static inline int dl_bw_cpus(int i) 1891{ 1892 struct root_domain *rd = cpu_rq(i)->rd; 1893 int cpus = 0; 1894 1895 for_each_cpu_and(i, rd->span, cpu_active_mask) 1896 cpus++; 1897 1898 return cpus; 1899} 1900#else 1901inline struct dl_bw *dl_bw_of(int i) 1902{ 1903 return &cpu_rq(i)->dl.dl_bw; 1904} 1905 1906static inline int dl_bw_cpus(int i) 1907{ 1908 return 1; 1909} 1910#endif 1911 1912static inline 1913void __dl_clear(struct dl_bw *dl_b, u64 tsk_bw) 1914{ 1915 dl_b->total_bw -= tsk_bw; 1916} 1917 1918static inline 1919void __dl_add(struct dl_bw *dl_b, u64 tsk_bw) 1920{ 1921 dl_b->total_bw += tsk_bw; 1922} 1923 1924static inline 1925bool __dl_overflow(struct dl_bw *dl_b, int cpus, u64 old_bw, u64 new_bw) 1926{ 1927 return dl_b->bw != -1 && 1928 dl_b->bw * cpus < dl_b->total_bw - old_bw + new_bw; 1929} 1930 1931/* 1932 * We must be sure that accepting a new task (or allowing changing the 1933 * parameters of an existing one) is consistent with the bandwidth 1934 * constraints. If yes, this function also accordingly updates the currently 1935 * allocated bandwidth to reflect the new situation. 1936 * 1937 * This function is called while holding p's rq->lock. 1938 */ 1939static int dl_overflow(struct task_struct *p, int policy, 1940 const struct sched_attr *attr) 1941{ 1942 1943 struct dl_bw *dl_b = dl_bw_of(task_cpu(p)); 1944 u64 period = attr->sched_period; 1945 u64 runtime = attr->sched_runtime; 1946 u64 new_bw = dl_policy(policy) ? to_ratio(period, runtime) : 0; 1947 int cpus, err = -1; 1948 1949 if (new_bw == p->dl.dl_bw) 1950 return 0; 1951 1952 /* 1953 * Either if a task, enters, leave, or stays -deadline but changes 1954 * its parameters, we may need to update accordingly the total 1955 * allocated bandwidth of the container. 1956 */ 1957 raw_spin_lock(&dl_b->lock); 1958 cpus = dl_bw_cpus(task_cpu(p)); 1959 if (dl_policy(policy) && !task_has_dl_policy(p) && 1960 !__dl_overflow(dl_b, cpus, 0, new_bw)) { 1961 __dl_add(dl_b, new_bw); 1962 err = 0; 1963 } else if (dl_policy(policy) && task_has_dl_policy(p) && 1964 !__dl_overflow(dl_b, cpus, p->dl.dl_bw, new_bw)) { 1965 __dl_clear(dl_b, p->dl.dl_bw); 1966 __dl_add(dl_b, new_bw); 1967 err = 0; 1968 } else if (!dl_policy(policy) && task_has_dl_policy(p)) { 1969 __dl_clear(dl_b, p->dl.dl_bw); 1970 err = 0; 1971 } 1972 raw_spin_unlock(&dl_b->lock); 1973 1974 return err; 1975} 1976 1977extern void init_dl_bw(struct dl_bw *dl_b); 1978 1979/* 1980 * wake_up_new_task - wake up a newly created task for the first time. 1981 * 1982 * This function will do some initial scheduler statistics housekeeping 1983 * that must be done for every newly created context, then puts the task 1984 * on the runqueue and wakes it. 1985 */ 1986void wake_up_new_task(struct task_struct *p) 1987{ 1988 unsigned long flags; 1989 struct rq *rq; 1990 1991 raw_spin_lock_irqsave(&p->pi_lock, flags); 1992#ifdef CONFIG_SMP 1993 /* 1994 * Fork balancing, do it here and not earlier because: 1995 * - cpus_allowed can change in the fork path 1996 * - any previously selected cpu might disappear through hotplug 1997 */ 1998 set_task_cpu(p, select_task_rq(p, task_cpu(p), SD_BALANCE_FORK, 0)); 1999#endif 2000 2001 /* Initialize new task's runnable average */ 2002 init_task_runnable_average(p); 2003 rq = __task_rq_lock(p); 2004 activate_task(rq, p, 0); 2005 p->on_rq = 1; 2006 trace_sched_wakeup_new(p, true); 2007 check_preempt_curr(rq, p, WF_FORK); 2008#ifdef CONFIG_SMP 2009 if (p->sched_class->task_woken) 2010 p->sched_class->task_woken(rq, p); 2011#endif 2012 task_rq_unlock(rq, p, &flags); 2013} 2014 2015#ifdef CONFIG_PREEMPT_NOTIFIERS 2016 2017/** 2018 * preempt_notifier_register - tell me when current is being preempted & rescheduled 2019 * @notifier: notifier struct to register 2020 */ 2021void preempt_notifier_register(struct preempt_notifier *notifier) 2022{ 2023 hlist_add_head(¬ifier->link, ¤t->preempt_notifiers); 2024} 2025EXPORT_SYMBOL_GPL(preempt_notifier_register); 2026 2027/** 2028 * preempt_notifier_unregister - no longer interested in preemption notifications 2029 * @notifier: notifier struct to unregister 2030 * 2031 * This is safe to call from within a preemption notifier. 2032 */ 2033void preempt_notifier_unregister(struct preempt_notifier *notifier) 2034{ 2035 hlist_del(¬ifier->link); 2036} 2037EXPORT_SYMBOL_GPL(preempt_notifier_unregister); 2038 2039static void fire_sched_in_preempt_notifiers(struct task_struct *curr) 2040{ 2041 struct preempt_notifier *notifier; 2042 2043 hlist_for_each_entry(notifier, &curr->preempt_notifiers, link) 2044 notifier->ops->sched_in(notifier, raw_smp_processor_id()); 2045} 2046 2047static void 2048fire_sched_out_preempt_notifiers(struct task_struct *curr, 2049 struct task_struct *next) 2050{ 2051 struct preempt_notifier *notifier; 2052 2053 hlist_for_each_entry(notifier, &curr->preempt_notifiers, link) 2054 notifier->ops->sched_out(notifier, next); 2055} 2056 2057#else /* !CONFIG_PREEMPT_NOTIFIERS */ 2058 2059static void fire_sched_in_preempt_notifiers(struct task_struct *curr) 2060{ 2061} 2062 2063static void 2064fire_sched_out_preempt_notifiers(struct task_struct *curr, 2065 struct task_struct *next) 2066{ 2067} 2068 2069#endif /* CONFIG_PREEMPT_NOTIFIERS */ 2070 2071/** 2072 * prepare_task_switch - prepare to switch tasks 2073 * @rq: the runqueue preparing to switch 2074 * @prev: the current task that is being switched out 2075 * @next: the task we are going to switch to. 2076 * 2077 * This is called with the rq lock held and interrupts off. It must 2078 * be paired with a subsequent finish_task_switch after the context 2079 * switch. 2080 * 2081 * prepare_task_switch sets up locking and calls architecture specific 2082 * hooks. 2083 */ 2084static inline void 2085prepare_task_switch(struct rq *rq, struct task_struct *prev, 2086 struct task_struct *next) 2087{ 2088 trace_sched_switch(prev, next); 2089 sched_info_switch(rq, prev, next); 2090 perf_event_task_sched_out(prev, next); 2091 fire_sched_out_preempt_notifiers(prev, next); 2092 prepare_lock_switch(rq, next); 2093 prepare_arch_switch(next); 2094} 2095 2096/** 2097 * finish_task_switch - clean up after a task-switch 2098 * @rq: runqueue associated with task-switch 2099 * @prev: the thread we just switched away from. 2100 * 2101 * finish_task_switch must be called after the context switch, paired 2102 * with a prepare_task_switch call before the context switch. 2103 * finish_task_switch will reconcile locking set up by prepare_task_switch, 2104 * and do any other architecture-specific cleanup actions. 2105 * 2106 * Note that we may have delayed dropping an mm in context_switch(). If 2107 * so, we finish that here outside of the runqueue lock. (Doing it 2108 * with the lock held can cause deadlocks; see schedule() for 2109 * details.) 2110 */ 2111static void finish_task_switch(struct rq *rq, struct task_struct *prev) 2112 __releases(rq->lock) 2113{ 2114 struct mm_struct *mm = rq->prev_mm; 2115 long prev_state; 2116 2117 rq->prev_mm = NULL; 2118 2119 /* 2120 * A task struct has one reference for the use as "current". 2121 * If a task dies, then it sets TASK_DEAD in tsk->state and calls 2122 * schedule one last time. The schedule call will never return, and 2123 * the scheduled task must drop that reference. 2124 * The test for TASK_DEAD must occur while the runqueue locks are 2125 * still held, otherwise prev could be scheduled on another cpu, die 2126 * there before we look at prev->state, and then the reference would 2127 * be dropped twice. 2128 * Manfred Spraul <manfred@colorfullife.com> 2129 */ 2130 prev_state = prev->state; 2131 vtime_task_switch(prev); 2132 finish_arch_switch(prev); 2133 perf_event_task_sched_in(prev, current); 2134 finish_lock_switch(rq, prev); 2135 finish_arch_post_lock_switch(); 2136 2137 fire_sched_in_preempt_notifiers(current); 2138 if (mm) 2139 mmdrop(mm); 2140 if (unlikely(prev_state == TASK_DEAD)) { 2141 task_numa_free(prev); 2142 2143 if (prev->sched_class->task_dead) 2144 prev->sched_class->task_dead(prev); 2145 2146 /* 2147 * Remove function-return probe instances associated with this 2148 * task and put them back on the free list. 2149 */ 2150 kprobe_flush_task(prev); 2151 put_task_struct(prev); 2152 } 2153 2154 tick_nohz_task_switch(current); 2155} 2156 2157#ifdef CONFIG_SMP 2158 2159/* assumes rq->lock is held */ 2160static inline void pre_schedule(struct rq *rq, struct task_struct *prev) 2161{ 2162 if (prev->sched_class->pre_schedule) 2163 prev->sched_class->pre_schedule(rq, prev); 2164} 2165 2166/* rq->lock is NOT held, but preemption is disabled */ 2167static inline void post_schedule(struct rq *rq) 2168{ 2169 if (rq->post_schedule) { 2170 unsigned long flags; 2171 2172 raw_spin_lock_irqsave(&rq->lock, flags); 2173 if (rq->curr->sched_class->post_schedule) 2174 rq->curr->sched_class->post_schedule(rq); 2175 raw_spin_unlock_irqrestore(&rq->lock, flags); 2176 2177 rq->post_schedule = 0; 2178 } 2179} 2180 2181#else 2182 2183static inline void pre_schedule(struct rq *rq, struct task_struct *p) 2184{ 2185} 2186 2187static inline void post_schedule(struct rq *rq) 2188{ 2189} 2190 2191#endif 2192 2193/** 2194 * schedule_tail - first thing a freshly forked thread must call. 2195 * @prev: the thread we just switched away from. 2196 */ 2197asmlinkage void schedule_tail(struct task_struct *prev) 2198 __releases(rq->lock) 2199{ 2200 struct rq *rq = this_rq(); 2201 2202 finish_task_switch(rq, prev); 2203 2204 /* 2205 * FIXME: do we need to worry about rq being invalidated by the 2206 * task_switch? 2207 */ 2208 post_schedule(rq); 2209 2210#ifdef __ARCH_WANT_UNLOCKED_CTXSW 2211 /* In this case, finish_task_switch does not reenable preemption */ 2212 preempt_enable(); 2213#endif 2214 if (current->set_child_tid) 2215 put_user(task_pid_vnr(current), current->set_child_tid); 2216} 2217 2218/* 2219 * context_switch - switch to the new MM and the new 2220 * thread's register state. 2221 */ 2222static inline void 2223context_switch(struct rq *rq, struct task_struct *prev, 2224 struct task_struct *next) 2225{ 2226 struct mm_struct *mm, *oldmm; 2227 2228 prepare_task_switch(rq, prev, next); 2229 2230 mm = next->mm; 2231 oldmm = prev->active_mm; 2232 /* 2233 * For paravirt, this is coupled with an exit in switch_to to 2234 * combine the page table reload and the switch backend into 2235 * one hypercall. 2236 */ 2237 arch_start_context_switch(prev); 2238 2239 if (!mm) { 2240 next->active_mm = oldmm; 2241 atomic_inc(&oldmm->mm_count); 2242 enter_lazy_tlb(oldmm, next); 2243 } else 2244 switch_mm(oldmm, mm, next); 2245 2246 if (!prev->mm) { 2247 prev->active_mm = NULL; 2248 rq->prev_mm = oldmm; 2249 } 2250 /* 2251 * Since the runqueue lock will be released by the next 2252 * task (which is an invalid locking op but in the case 2253 * of the scheduler it's an obvious special-case), so we 2254 * do an early lockdep release here: 2255 */ 2256#ifndef __ARCH_WANT_UNLOCKED_CTXSW 2257 spin_release(&rq->lock.dep_map, 1, _THIS_IP_); 2258#endif 2259 2260 context_tracking_task_switch(prev, next); 2261 /* Here we just switch the register state and the stack. */ 2262 switch_to(prev, next, prev); 2263 2264 barrier(); 2265 /* 2266 * this_rq must be evaluated again because prev may have moved 2267 * CPUs since it called schedule(), thus the 'rq' on its stack 2268 * frame will be invalid. 2269 */ 2270 finish_task_switch(this_rq(), prev); 2271} 2272 2273/* 2274 * nr_running and nr_context_switches: 2275 * 2276 * externally visible scheduler statistics: current number of runnable 2277 * threads, total number of context switches performed since bootup. 2278 */ 2279unsigned long nr_running(void) 2280{ 2281 unsigned long i, sum = 0; 2282 2283 for_each_online_cpu(i) 2284 sum += cpu_rq(i)->nr_running; 2285 2286 return sum; 2287} 2288 2289unsigned long long nr_context_switches(void) 2290{ 2291 int i; 2292 unsigned long long sum = 0; 2293 2294 for_each_possible_cpu(i) 2295 sum += cpu_rq(i)->nr_switches; 2296 2297 return sum; 2298} 2299 2300unsigned long nr_iowait(void) 2301{ 2302 unsigned long i, sum = 0; 2303 2304 for_each_possible_cpu(i) 2305 sum += atomic_read(&cpu_rq(i)->nr_iowait); 2306 2307 return sum; 2308} 2309 2310unsigned long nr_iowait_cpu(int cpu) 2311{ 2312 struct rq *this = cpu_rq(cpu); 2313 return atomic_read(&this->nr_iowait); 2314} 2315 2316#ifdef CONFIG_SMP 2317 2318/* 2319 * sched_exec - execve() is a valuable balancing opportunity, because at 2320 * this point the task has the smallest effective memory and cache footprint. 2321 */ 2322void sched_exec(void) 2323{ 2324 struct task_struct *p = current; 2325 unsigned long flags; 2326 int dest_cpu; 2327 2328 raw_spin_lock_irqsave(&p->pi_lock, flags); 2329 dest_cpu = p->sched_class->select_task_rq(p, task_cpu(p), SD_BALANCE_EXEC, 0); 2330 if (dest_cpu == smp_processor_id()) 2331 goto unlock; 2332 2333 if (likely(cpu_active(dest_cpu))) { 2334 struct migration_arg arg = { p, dest_cpu }; 2335 2336 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 2337 stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg); 2338 return; 2339 } 2340unlock: 2341 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 2342} 2343 2344#endif 2345 2346DEFINE_PER_CPU(struct kernel_stat, kstat); 2347DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat); 2348 2349EXPORT_PER_CPU_SYMBOL(kstat); 2350EXPORT_PER_CPU_SYMBOL(kernel_cpustat); 2351 2352/* 2353 * Return any ns on the sched_clock that have not yet been accounted in 2354 * @p in case that task is currently running. 2355 * 2356 * Called with task_rq_lock() held on @rq. 2357 */ 2358static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq) 2359{ 2360 u64 ns = 0; 2361 2362 if (task_current(rq, p)) { 2363 update_rq_clock(rq); 2364 ns = rq_clock_task(rq) - p->se.exec_start; 2365 if ((s64)ns < 0) 2366 ns = 0; 2367 } 2368 2369 return ns; 2370} 2371 2372unsigned long long task_delta_exec(struct task_struct *p) 2373{ 2374 unsigned long flags; 2375 struct rq *rq; 2376 u64 ns = 0; 2377 2378 rq = task_rq_lock(p, &flags); 2379 ns = do_task_delta_exec(p, rq); 2380 task_rq_unlock(rq, p, &flags); 2381 2382 return ns; 2383} 2384 2385/* 2386 * Return accounted runtime for the task. 2387 * In case the task is currently running, return the runtime plus current's 2388 * pending runtime that have not been accounted yet. 2389 */ 2390unsigned long long task_sched_runtime(struct task_struct *p) 2391{ 2392 unsigned long flags; 2393 struct rq *rq; 2394 u64 ns = 0; 2395 2396#if defined(CONFIG_64BIT) && defined(CONFIG_SMP) 2397 /* 2398 * 64-bit doesn't need locks to atomically read a 64bit value. 2399 * So we have a optimization chance when the task's delta_exec is 0. 2400 * Reading ->on_cpu is racy, but this is ok. 2401 * 2402 * If we race with it leaving cpu, we'll take a lock. So we're correct. 2403 * If we race with it entering cpu, unaccounted time is 0. This is 2404 * indistinguishable from the read occurring a few cycles earlier. 2405 */ 2406 if (!p->on_cpu) 2407 return p->se.sum_exec_runtime; 2408#endif 2409 2410 rq = task_rq_lock(p, &flags); 2411 ns = p->se.sum_exec_runtime + do_task_delta_exec(p, rq); 2412 task_rq_unlock(rq, p, &flags); 2413 2414 return ns; 2415} 2416 2417/* 2418 * This function gets called by the timer code, with HZ frequency. 2419 * We call it with interrupts disabled. 2420 */ 2421void scheduler_tick(void) 2422{ 2423 int cpu = smp_processor_id(); 2424 struct rq *rq = cpu_rq(cpu); 2425 struct task_struct *curr = rq->curr; 2426 2427 sched_clock_tick(); 2428 2429 raw_spin_lock(&rq->lock); 2430 update_rq_clock(rq); 2431 curr->sched_class->task_tick(rq, curr, 0); 2432 update_cpu_load_active(rq); 2433 raw_spin_unlock(&rq->lock); 2434 2435 perf_event_task_tick(); 2436 2437#ifdef CONFIG_SMP 2438 rq->idle_balance = idle_cpu(cpu); 2439 trigger_load_balance(rq, cpu); 2440#endif 2441 rq_last_tick_reset(rq); 2442} 2443 2444#ifdef CONFIG_NO_HZ_FULL 2445/** 2446 * scheduler_tick_max_deferment 2447 * 2448 * Keep at least one tick per second when a single 2449 * active task is running because the scheduler doesn't 2450 * yet completely support full dynticks environment. 2451 * 2452 * This makes sure that uptime, CFS vruntime, load 2453 * balancing, etc... continue to move forward, even 2454 * with a very low granularity. 2455 * 2456 * Return: Maximum deferment in nanoseconds. 2457 */ 2458u64 scheduler_tick_max_deferment(void) 2459{ 2460 struct rq *rq = this_rq(); 2461 unsigned long next, now = ACCESS_ONCE(jiffies); 2462 2463 next = rq->last_sched_tick + HZ; 2464 2465 if (time_before_eq(next, now)) 2466 return 0; 2467 2468 return jiffies_to_usecs(next - now) * NSEC_PER_USEC; 2469} 2470#endif 2471 2472notrace unsigned long get_parent_ip(unsigned long addr) 2473{ 2474 if (in_lock_functions(addr)) { 2475 addr = CALLER_ADDR2; 2476 if (in_lock_functions(addr)) 2477 addr = CALLER_ADDR3; 2478 } 2479 return addr; 2480} 2481 2482#if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \ 2483 defined(CONFIG_PREEMPT_TRACER)) 2484 2485void __kprobes preempt_count_add(int val) 2486{ 2487#ifdef CONFIG_DEBUG_PREEMPT 2488 /* 2489 * Underflow? 2490 */ 2491 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) 2492 return; 2493#endif 2494 __preempt_count_add(val); 2495#ifdef CONFIG_DEBUG_PREEMPT 2496 /* 2497 * Spinlock count overflowing soon? 2498 */ 2499 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= 2500 PREEMPT_MASK - 10); 2501#endif 2502 if (preempt_count() == val) 2503 trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); 2504} 2505EXPORT_SYMBOL(preempt_count_add); 2506 2507void __kprobes preempt_count_sub(int val) 2508{ 2509#ifdef CONFIG_DEBUG_PREEMPT 2510 /* 2511 * Underflow? 2512 */ 2513 if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) 2514 return; 2515 /* 2516 * Is the spinlock portion underflowing? 2517 */ 2518 if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && 2519 !(preempt_count() & PREEMPT_MASK))) 2520 return; 2521#endif 2522 2523 if (preempt_count() == val) 2524 trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); 2525 __preempt_count_sub(val); 2526} 2527EXPORT_SYMBOL(preempt_count_sub); 2528 2529#endif 2530 2531/* 2532 * Print scheduling while atomic bug: 2533 */ 2534static noinline void __schedule_bug(struct task_struct *prev) 2535{ 2536 if (oops_in_progress) 2537 return; 2538 2539 printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n", 2540 prev->comm, prev->pid, preempt_count()); 2541 2542 debug_show_held_locks(prev); 2543 print_modules(); 2544 if (irqs_disabled()) 2545 print_irqtrace_events(prev); 2546 dump_stack(); 2547 add_taint(TAINT_WARN, LOCKDEP_STILL_OK); 2548} 2549 2550/* 2551 * Various schedule()-time debugging checks and statistics: 2552 */ 2553static inline void schedule_debug(struct task_struct *prev) 2554{ 2555 /* 2556 * Test if we are atomic. Since do_exit() needs to call into 2557 * schedule() atomically, we ignore that path. Otherwise whine 2558 * if we are scheduling when we should not. 2559 */ 2560 if (unlikely(in_atomic_preempt_off() && prev->state != TASK_DEAD)) 2561 __schedule_bug(prev); 2562 rcu_sleep_check(); 2563 2564 profile_hit(SCHED_PROFILING, __builtin_return_address(0)); 2565 2566 schedstat_inc(this_rq(), sched_count); 2567} 2568 2569static void put_prev_task(struct rq *rq, struct task_struct *prev) 2570{ 2571 if (prev->on_rq || rq->skip_clock_update < 0) 2572 update_rq_clock(rq); 2573 prev->sched_class->put_prev_task(rq, prev); 2574} 2575 2576/* 2577 * Pick up the highest-prio task: 2578 */ 2579static inline struct task_struct * 2580pick_next_task(struct rq *rq) 2581{ 2582 const struct sched_class *class; 2583 struct task_struct *p; 2584 2585 /* 2586 * Optimization: we know that if all tasks are in 2587 * the fair class we can call that function directly: 2588 */ 2589 if (likely(rq->nr_running == rq->cfs.h_nr_running)) { 2590 p = fair_sched_class.pick_next_task(rq); 2591 if (likely(p)) 2592 return p; 2593 } 2594 2595 for_each_class(class) { 2596 p = class->pick_next_task(rq); 2597 if (p) 2598 return p; 2599 } 2600 2601 BUG(); /* the idle class will always have a runnable task */ 2602} 2603 2604/* 2605 * __schedule() is the main scheduler function. 2606 * 2607 * The main means of driving the scheduler and thus entering this function are: 2608 * 2609 * 1. Explicit blocking: mutex, semaphore, waitqueue, etc. 2610 * 2611 * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return 2612 * paths. For example, see arch/x86/entry_64.S. 2613 * 2614 * To drive preemption between tasks, the scheduler sets the flag in timer 2615 * interrupt handler scheduler_tick(). 2616 * 2617 * 3. Wakeups don't really cause entry into schedule(). They add a 2618 * task to the run-queue and that's it. 2619 * 2620 * Now, if the new task added to the run-queue preempts the current 2621 * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets 2622 * called on the nearest possible occasion: 2623 * 2624 * - If the kernel is preemptible (CONFIG_PREEMPT=y): 2625 * 2626 * - in syscall or exception context, at the next outmost 2627 * preempt_enable(). (this might be as soon as the wake_up()'s 2628 * spin_unlock()!) 2629 * 2630 * - in IRQ context, return from interrupt-handler to 2631 * preemptible context 2632 * 2633 * - If the kernel is not preemptible (CONFIG_PREEMPT is not set) 2634 * then at the next: 2635 * 2636 * - cond_resched() call 2637 * - explicit schedule() call 2638 * - return from syscall or exception to user-space 2639 * - return from interrupt-handler to user-space 2640 */ 2641static void __sched __schedule(void) 2642{ 2643 struct task_struct *prev, *next; 2644 unsigned long *switch_count; 2645 struct rq *rq; 2646 int cpu; 2647 2648need_resched: 2649 preempt_disable(); 2650 cpu = smp_processor_id(); 2651 rq = cpu_rq(cpu); 2652 rcu_note_context_switch(cpu); 2653 prev = rq->curr; 2654 2655 schedule_debug(prev); 2656 2657 if (sched_feat(HRTICK)) 2658 hrtick_clear(rq); 2659 2660 /* 2661 * Make sure that signal_pending_state()->signal_pending() below 2662 * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE) 2663 * done by the caller to avoid the race with signal_wake_up(). 2664 */ 2665 smp_mb__before_spinlock(); 2666 raw_spin_lock_irq(&rq->lock); 2667 2668 switch_count = &prev->nivcsw; 2669 if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { 2670 if (unlikely(signal_pending_state(prev->state, prev))) { 2671 prev->state = TASK_RUNNING; 2672 } else { 2673 deactivate_task(rq, prev, DEQUEUE_SLEEP); 2674 prev->on_rq = 0; 2675 2676 /* 2677 * If a worker went to sleep, notify and ask workqueue 2678 * whether it wants to wake up a task to maintain 2679 * concurrency. 2680 */ 2681 if (prev->flags & PF_WQ_WORKER) { 2682 struct task_struct *to_wakeup; 2683 2684 to_wakeup = wq_worker_sleeping(prev, cpu); 2685 if (to_wakeup) 2686 try_to_wake_up_local(to_wakeup); 2687 } 2688 } 2689 switch_count = &prev->nvcsw; 2690 } 2691 2692 pre_schedule(rq, prev); 2693 2694 if (unlikely(!rq->nr_running)) 2695 idle_balance(cpu, rq); 2696 2697 put_prev_task(rq, prev); 2698 next = pick_next_task(rq); 2699 clear_tsk_need_resched(prev); 2700 clear_preempt_need_resched(); 2701 rq->skip_clock_update = 0; 2702 2703 if (likely(prev != next)) { 2704 rq->nr_switches++; 2705 rq->curr = next; 2706 ++*switch_count; 2707 2708 context_switch(rq, prev, next); /* unlocks the rq */ 2709 /* 2710 * The context switch have flipped the stack from under us 2711 * and restored the local variables which were saved when 2712 * this task called schedule() in the past. prev == current 2713 * is still correct, but it can be moved to another cpu/rq. 2714 */ 2715 cpu = smp_processor_id(); 2716 rq = cpu_rq(cpu); 2717 } else 2718 raw_spin_unlock_irq(&rq->lock); 2719 2720 post_schedule(rq); 2721 2722 sched_preempt_enable_no_resched(); 2723 if (need_resched()) 2724 goto need_resched; 2725} 2726 2727static inline void sched_submit_work(struct task_struct *tsk) 2728{ 2729 if (!tsk->state || tsk_is_pi_blocked(tsk)) 2730 return; 2731 /* 2732 * If we are going to sleep and we have plugged IO queued, 2733 * make sure to submit it to avoid deadlocks. 2734 */ 2735 if (blk_needs_flush_plug(tsk)) 2736 blk_schedule_flush_plug(tsk); 2737} 2738 2739asmlinkage void __sched schedule(void) 2740{ 2741 struct task_struct *tsk = current; 2742 2743 sched_submit_work(tsk); 2744 __schedule(); 2745} 2746EXPORT_SYMBOL(schedule); 2747 2748#ifdef CONFIG_CONTEXT_TRACKING 2749asmlinkage void __sched schedule_user(void) 2750{ 2751 /* 2752 * If we come here after a random call to set_need_resched(), 2753 * or we have been woken up remotely but the IPI has not yet arrived, 2754 * we haven't yet exited the RCU idle mode. Do it here manually until 2755 * we find a better solution. 2756 */ 2757 user_exit(); 2758 schedule(); 2759 user_enter(); 2760} 2761#endif 2762 2763/** 2764 * schedule_preempt_disabled - called with preemption disabled 2765 * 2766 * Returns with preemption disabled. Note: preempt_count must be 1 2767 */ 2768void __sched schedule_preempt_disabled(void) 2769{ 2770 sched_preempt_enable_no_resched(); 2771 schedule(); 2772 preempt_disable(); 2773} 2774 2775#ifdef CONFIG_PREEMPT 2776/* 2777 * this is the entry point to schedule() from in-kernel preemption 2778 * off of preempt_enable. Kernel preemptions off return from interrupt 2779 * occur there and call schedule directly. 2780 */ 2781asmlinkage void __sched notrace preempt_schedule(void) 2782{ 2783 /* 2784 * If there is a non-zero preempt_count or interrupts are disabled, 2785 * we do not want to preempt the current task. Just return.. 2786 */ 2787 if (likely(!preemptible())) 2788 return; 2789 2790 do { 2791 __preempt_count_add(PREEMPT_ACTIVE); 2792 __schedule(); 2793 __preempt_count_sub(PREEMPT_ACTIVE); 2794 2795 /* 2796 * Check again in case we missed a preemption opportunity 2797 * between schedule and now. 2798 */ 2799 barrier(); 2800 } while (need_resched()); 2801} 2802EXPORT_SYMBOL(preempt_schedule); 2803#endif /* CONFIG_PREEMPT */ 2804 2805/* 2806 * this is the entry point to schedule() from kernel preemption 2807 * off of irq context. 2808 * Note, that this is called and return with irqs disabled. This will 2809 * protect us against recursive calling from irq. 2810 */ 2811asmlinkage void __sched preempt_schedule_irq(void) 2812{ 2813 enum ctx_state prev_state; 2814 2815 /* Catch callers which need to be fixed */ 2816 BUG_ON(preempt_count() || !irqs_disabled()); 2817 2818 prev_state = exception_enter(); 2819 2820 do { 2821 __preempt_count_add(PREEMPT_ACTIVE); 2822 local_irq_enable(); 2823 __schedule(); 2824 local_irq_disable(); 2825 __preempt_count_sub(PREEMPT_ACTIVE); 2826 2827 /* 2828 * Check again in case we missed a preemption opportunity 2829 * between schedule and now. 2830 */ 2831 barrier(); 2832 } while (need_resched()); 2833 2834 exception_exit(prev_state); 2835} 2836 2837int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags, 2838 void *key) 2839{ 2840 return try_to_wake_up(curr->private, mode, wake_flags); 2841} 2842EXPORT_SYMBOL(default_wake_function); 2843 2844static long __sched 2845sleep_on_common(wait_queue_head_t *q, int state, long timeout) 2846{ 2847 unsigned long flags; 2848 wait_queue_t wait; 2849 2850 init_waitqueue_entry(&wait, current); 2851 2852 __set_current_state(state); 2853 2854 spin_lock_irqsave(&q->lock, flags); 2855 __add_wait_queue(q, &wait); 2856 spin_unlock(&q->lock); 2857 timeout = schedule_timeout(timeout); 2858 spin_lock_irq(&q->lock); 2859 __remove_wait_queue(q, &wait); 2860 spin_unlock_irqrestore(&q->lock, flags); 2861 2862 return timeout; 2863} 2864 2865void __sched interruptible_sleep_on(wait_queue_head_t *q) 2866{ 2867 sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); 2868} 2869EXPORT_SYMBOL(interruptible_sleep_on); 2870 2871long __sched 2872interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout) 2873{ 2874 return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout); 2875} 2876EXPORT_SYMBOL(interruptible_sleep_on_timeout); 2877 2878void __sched sleep_on(wait_queue_head_t *q) 2879{ 2880 sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); 2881} 2882EXPORT_SYMBOL(sleep_on); 2883 2884long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout) 2885{ 2886 return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout); 2887} 2888EXPORT_SYMBOL(sleep_on_timeout); 2889 2890#ifdef CONFIG_RT_MUTEXES 2891 2892/* 2893 * rt_mutex_setprio - set the current priority of a task 2894 * @p: task 2895 * @prio: prio value (kernel-internal form) 2896 * 2897 * This function changes the 'effective' priority of a task. It does 2898 * not touch ->normal_prio like __setscheduler(). 2899 * 2900 * Used by the rt_mutex code to implement priority inheritance logic. 2901 */ 2902void rt_mutex_setprio(struct task_struct *p, int prio) 2903{ 2904 int oldprio, on_rq, running, enqueue_flag = 0; 2905 struct rq *rq; 2906 const struct sched_class *prev_class; 2907 2908 BUG_ON(prio > MAX_PRIO); 2909 2910 rq = __task_rq_lock(p); 2911 2912 /* 2913 * Idle task boosting is a nono in general. There is one 2914 * exception, when PREEMPT_RT and NOHZ is active: 2915 * 2916 * The idle task calls get_next_timer_interrupt() and holds 2917 * the timer wheel base->lock on the CPU and another CPU wants 2918 * to access the timer (probably to cancel it). We can safely 2919 * ignore the boosting request, as the idle CPU runs this code 2920 * with interrupts disabled and will complete the lock 2921 * protected section without being interrupted. So there is no 2922 * real need to boost. 2923 */ 2924 if (unlikely(p == rq->idle)) { 2925 WARN_ON(p != rq->curr); 2926 WARN_ON(p->pi_blocked_on); 2927 goto out_unlock; 2928 } 2929 2930 trace_sched_pi_setprio(p, prio); 2931 p->pi_top_task = rt_mutex_get_top_task(p); 2932 oldprio = p->prio; 2933 prev_class = p->sched_class; 2934 on_rq = p->on_rq; 2935 running = task_current(rq, p); 2936 if (on_rq) 2937 dequeue_task(rq, p, 0); 2938 if (running) 2939 p->sched_class->put_prev_task(rq, p); 2940 2941 /* 2942 * Boosting condition are: 2943 * 1. -rt task is running and holds mutex A 2944 * --> -dl task blocks on mutex A 2945 * 2946 * 2. -dl task is running and holds mutex A 2947 * --> -dl task blocks on mutex A and could preempt the 2948 * running task 2949 */ 2950 if (dl_prio(prio)) { 2951 if (!dl_prio(p->normal_prio) || (p->pi_top_task && 2952 dl_entity_preempt(&p->pi_top_task->dl, &p->dl))) { 2953 p->dl.dl_boosted = 1; 2954 p->dl.dl_throttled = 0; 2955 enqueue_flag = ENQUEUE_REPLENISH; 2956 } else 2957 p->dl.dl_boosted = 0; 2958 p->sched_class = &dl_sched_class; 2959 } else if (rt_prio(prio)) { 2960 if (dl_prio(oldprio)) 2961 p->dl.dl_boosted = 0; 2962 if (oldprio < prio) 2963 enqueue_flag = ENQUEUE_HEAD; 2964 p->sched_class = &rt_sched_class; 2965 } else { 2966 if (dl_prio(oldprio)) 2967 p->dl.dl_boosted = 0; 2968 p->sched_class = &fair_sched_class; 2969 } 2970 2971 p->prio = prio; 2972 2973 if (running) 2974 p->sched_class->set_curr_task(rq); 2975 if (on_rq) 2976 enqueue_task(rq, p, enqueue_flag); 2977 2978 check_class_changed(rq, p, prev_class, oldprio); 2979out_unlock: 2980 __task_rq_unlock(rq); 2981} 2982#endif 2983 2984void set_user_nice(struct task_struct *p, long nice) 2985{ 2986 int old_prio, delta, on_rq; 2987 unsigned long flags; 2988 struct rq *rq; 2989 2990 if (TASK_NICE(p) == nice || nice < -20 || nice > 19) 2991 return; 2992 /* 2993 * We have to be careful, if called from sys_setpriority(), 2994 * the task might be in the middle of scheduling on another CPU. 2995 */ 2996 rq = task_rq_lock(p, &flags); 2997 /* 2998 * The RT priorities are set via sched_setscheduler(), but we still 2999 * allow the 'normal' nice value to be set - but as expected 3000 * it wont have any effect on scheduling until the task is 3001 * SCHED_DEADLINE, SCHED_FIFO or SCHED_RR: 3002 */ 3003 if (task_has_dl_policy(p) || task_has_rt_policy(p)) { 3004 p->static_prio = NICE_TO_PRIO(nice); 3005 goto out_unlock; 3006 } 3007 on_rq = p->on_rq; 3008 if (on_rq) 3009 dequeue_task(rq, p, 0); 3010 3011 p->static_prio = NICE_TO_PRIO(nice); 3012 set_load_weight(p); 3013 old_prio = p->prio; 3014 p->prio = effective_prio(p); 3015 delta = p->prio - old_prio; 3016 3017 if (on_rq) { 3018 enqueue_task(rq, p, 0); 3019 /* 3020 * If the task increased its priority or is running and 3021 * lowered its priority, then reschedule its CPU: 3022 */ 3023 if (delta < 0 || (delta > 0 && task_running(rq, p))) 3024 resched_task(rq->curr); 3025 } 3026out_unlock: 3027 task_rq_unlock(rq, p, &flags); 3028} 3029EXPORT_SYMBOL(set_user_nice); 3030 3031/* 3032 * can_nice - check if a task can reduce its nice value 3033 * @p: task 3034 * @nice: nice value 3035 */ 3036int can_nice(const struct task_struct *p, const int nice) 3037{ 3038 /* convert nice value [19,-20] to rlimit style value [1,40] */ 3039 int nice_rlim = 20 - nice; 3040 3041 return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) || 3042 capable(CAP_SYS_NICE)); 3043} 3044 3045#ifdef __ARCH_WANT_SYS_NICE 3046 3047/* 3048 * sys_nice - change the priority of the current process. 3049 * @increment: priority increment 3050 * 3051 * sys_setpriority is a more generic, but much slower function that 3052 * does similar things. 3053 */ 3054SYSCALL_DEFINE1(nice, int, increment) 3055{ 3056 long nice, retval; 3057 3058 /* 3059 * Setpriority might change our priority at the same moment. 3060 * We don't have to worry. Conceptually one call occurs first 3061 * and we have a single winner. 3062 */ 3063 if (increment < -40) 3064 increment = -40; 3065 if (increment > 40) 3066 increment = 40; 3067 3068 nice = TASK_NICE(current) + increment; 3069 if (nice < -20) 3070 nice = -20; 3071 if (nice > 19) 3072 nice = 19; 3073 3074 if (increment < 0 && !can_nice(current, nice)) 3075 return -EPERM; 3076 3077 retval = security_task_setnice(current, nice); 3078 if (retval) 3079 return retval; 3080 3081 set_user_nice(current, nice); 3082 return 0; 3083} 3084 3085#endif 3086 3087/** 3088 * task_prio - return the priority value of a given task. 3089 * @p: the task in question. 3090 * 3091 * Return: The priority value as seen by users in /proc. 3092 * RT tasks are offset by -200. Normal tasks are centered 3093 * around 0, value goes from -16 to +15. 3094 */ 3095int task_prio(const struct task_struct *p) 3096{ 3097 return p->prio - MAX_RT_PRIO; 3098} 3099 3100/** 3101 * task_nice - return the nice value of a given task. 3102 * @p: the task in question. 3103 * 3104 * Return: The nice value [ -20 ... 0 ... 19 ]. 3105 */ 3106int task_nice(const struct task_struct *p) 3107{ 3108 return TASK_NICE(p); 3109} 3110EXPORT_SYMBOL(task_nice); 3111 3112/** 3113 * idle_cpu - is a given cpu idle currently? 3114 * @cpu: the processor in question. 3115 * 3116 * Return: 1 if the CPU is currently idle. 0 otherwise. 3117 */ 3118int idle_cpu(int cpu) 3119{ 3120 struct rq *rq = cpu_rq(cpu); 3121 3122 if (rq->curr != rq->idle) 3123 return 0; 3124 3125 if (rq->nr_running) 3126 return 0; 3127 3128#ifdef CONFIG_SMP 3129 if (!llist_empty(&rq->wake_list)) 3130 return 0; 3131#endif 3132 3133 return 1; 3134} 3135 3136/** 3137 * idle_task - return the idle task for a given cpu. 3138 * @cpu: the processor in question. 3139 * 3140 * Return: The idle task for the cpu @cpu. 3141 */ 3142struct task_struct *idle_task(int cpu) 3143{ 3144 return cpu_rq(cpu)->idle; 3145} 3146 3147/** 3148 * find_process_by_pid - find a process with a matching PID value. 3149 * @pid: the pid in question. 3150 * 3151 * The task of @pid, if found. %NULL otherwise. 3152 */ 3153static struct task_struct *find_process_by_pid(pid_t pid) 3154{ 3155 return pid ? find_task_by_vpid(pid) : current; 3156} 3157 3158/* 3159 * This function initializes the sched_dl_entity of a newly becoming 3160 * SCHED_DEADLINE task. 3161 * 3162 * Only the static values are considered here, the actual runtime and the 3163 * absolute deadline will be properly calculated when the task is enqueued 3164 * for the first time with its new policy. 3165 */ 3166static void 3167__setparam_dl(struct task_struct *p, const struct sched_attr *attr) 3168{ 3169 struct sched_dl_entity *dl_se = &p->dl; 3170 3171 init_dl_task_timer(dl_se); 3172 dl_se->dl_runtime = attr->sched_runtime; 3173 dl_se->dl_deadline = attr->sched_deadline; 3174 dl_se->dl_period = attr->sched_period ?: dl_se->dl_deadline; 3175 dl_se->flags = attr->sched_flags; 3176 dl_se->dl_bw = to_ratio(dl_se->dl_period, dl_se->dl_runtime); 3177 dl_se->dl_throttled = 0; 3178 dl_se->dl_new = 1; 3179} 3180 3181/* Actually do priority change: must hold pi & rq lock. */ 3182static void __setscheduler(struct rq *rq, struct task_struct *p, 3183 const struct sched_attr *attr) 3184{ 3185 int policy = attr->sched_policy; 3186 3187 p->policy = policy; 3188 3189 if (dl_policy(policy)) 3190 __setparam_dl(p, attr); 3191 else if (rt_policy(policy)) 3192 p->rt_priority = attr->sched_priority; 3193 else 3194 p->static_prio = NICE_TO_PRIO(attr->sched_nice); 3195 3196 p->normal_prio = normal_prio(p); 3197 p->prio = rt_mutex_getprio(p); 3198 3199 if (dl_prio(p->prio)) 3200 p->sched_class = &dl_sched_class; 3201 else if (rt_prio(p->prio)) 3202 p->sched_class = &rt_sched_class; 3203 else 3204 p->sched_class = &fair_sched_class; 3205 3206 set_load_weight(p); 3207} 3208 3209static void 3210__getparam_dl(struct task_struct *p, struct sched_attr *attr) 3211{ 3212 struct sched_dl_entity *dl_se = &p->dl; 3213 3214 attr->sched_priority = p->rt_priority; 3215 attr->sched_runtime = dl_se->dl_runtime; 3216 attr->sched_deadline = dl_se->dl_deadline; 3217 attr->sched_period = dl_se->dl_period; 3218 attr->sched_flags = dl_se->flags; 3219} 3220 3221/* 3222 * This function validates the new parameters of a -deadline task. 3223 * We ask for the deadline not being zero, and greater or equal 3224 * than the runtime, as well as the period of being zero or 3225 * greater than deadline. Furthermore, we have to be sure that 3226 * user parameters are above the internal resolution (1us); we 3227 * check sched_runtime only since it is always the smaller one. 3228 */ 3229static bool 3230__checkparam_dl(const struct sched_attr *attr) 3231{ 3232 return attr && attr->sched_deadline != 0 && 3233 (attr->sched_period == 0 || 3234 (s64)(attr->sched_period - attr->sched_deadline) >= 0) && 3235 (s64)(attr->sched_deadline - attr->sched_runtime ) >= 0 && 3236 attr->sched_runtime >= (2 << (DL_SCALE - 1)); 3237} 3238 3239/* 3240 * check the target process has a UID that matches the current process's 3241 */ 3242static bool check_same_owner(struct task_struct *p) 3243{ 3244 const struct cred *cred = current_cred(), *pcred; 3245 bool match; 3246 3247 rcu_read_lock(); 3248 pcred = __task_cred(p); 3249 match = (uid_eq(cred->euid, pcred->euid) || 3250 uid_eq(cred->euid, pcred->uid)); 3251 rcu_read_unlock(); 3252 return match; 3253} 3254 3255static int __sched_setscheduler(struct task_struct *p, 3256 const struct sched_attr *attr, 3257 bool user) 3258{ 3259 int retval, oldprio, oldpolicy = -1, on_rq, running; 3260 int policy = attr->sched_policy; 3261 unsigned long flags; 3262 const struct sched_class *prev_class; 3263 struct rq *rq; 3264 int reset_on_fork; 3265 3266 /* may grab non-irq protected spin_locks */ 3267 BUG_ON(in_interrupt()); 3268recheck: 3269 /* double check policy once rq lock held */ 3270 if (policy < 0) { 3271 reset_on_fork = p->sched_reset_on_fork; 3272 policy = oldpolicy = p->policy; 3273 } else { 3274 reset_on_fork = !!(policy & SCHED_RESET_ON_FORK); 3275 policy &= ~SCHED_RESET_ON_FORK; 3276 3277 if (policy != SCHED_DEADLINE && 3278 policy != SCHED_FIFO && policy != SCHED_RR && 3279 policy != SCHED_NORMAL && policy != SCHED_BATCH && 3280 policy != SCHED_IDLE) 3281 return -EINVAL; 3282 } 3283 3284 /* 3285 * Valid priorities for SCHED_FIFO and SCHED_RR are 3286 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL, 3287 * SCHED_BATCH and SCHED_IDLE is 0. 3288 */ 3289 if (attr->sched_priority < 0 || 3290 (p->mm && attr->sched_priority > MAX_USER_RT_PRIO-1) || 3291 (!p->mm && attr->sched_priority > MAX_RT_PRIO-1)) 3292 return -EINVAL; 3293 if ((dl_policy(policy) && !__checkparam_dl(attr)) || 3294 (rt_policy(policy) != (attr->sched_priority != 0))) 3295 return -EINVAL; 3296 3297 /* 3298 * Allow unprivileged RT tasks to decrease priority: 3299 */ 3300 if (user && !capable(CAP_SYS_NICE)) { 3301 if (fair_policy(policy)) { 3302 if (!can_nice(p, attr->sched_nice)) 3303 return -EPERM; 3304 } 3305 3306 if (rt_policy(policy)) { 3307 unsigned long rlim_rtprio = 3308 task_rlimit(p, RLIMIT_RTPRIO); 3309 3310 /* can't set/change the rt policy */ 3311 if (policy != p->policy && !rlim_rtprio) 3312 return -EPERM; 3313 3314 /* can't increase priority */ 3315 if (attr->sched_priority > p->rt_priority && 3316 attr->sched_priority > rlim_rtprio) 3317 return -EPERM; 3318 } 3319 3320 /* 3321 * Treat SCHED_IDLE as nice 20. Only allow a switch to 3322 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it. 3323 */ 3324 if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) { 3325 if (!can_nice(p, TASK_NICE(p))) 3326 return -EPERM; 3327 } 3328 3329 /* can't change other user's priorities */ 3330 if (!check_same_owner(p)) 3331 return -EPERM; 3332 3333 /* Normal users shall not reset the sched_reset_on_fork flag */ 3334 if (p->sched_reset_on_fork && !reset_on_fork) 3335 return -EPERM; 3336 } 3337 3338 if (user) { 3339 retval = security_task_setscheduler(p); 3340 if (retval) 3341 return retval; 3342 } 3343 3344 /* 3345 * make sure no PI-waiters arrive (or leave) while we are 3346 * changing the priority of the task: 3347 * 3348 * To be able to change p->policy safely, the appropriate 3349 * runqueue lock must be held. 3350 */ 3351 rq = task_rq_lock(p, &flags); 3352 3353 /* 3354 * Changing the policy of the stop threads its a very bad idea 3355 */ 3356 if (p == rq->stop) { 3357 task_rq_unlock(rq, p, &flags); 3358 return -EINVAL; 3359 } 3360 3361 /* 3362 * If not changing anything there's no need to proceed further: 3363 */ 3364 if (unlikely(policy == p->policy)) { 3365 if (fair_policy(policy) && attr->sched_nice != TASK_NICE(p)) 3366 goto change; 3367 if (rt_policy(policy) && attr->sched_priority != p->rt_priority) 3368 goto change; 3369 if (dl_policy(policy)) 3370 goto change; 3371 3372 task_rq_unlock(rq, p, &flags); 3373 return 0; 3374 } 3375change: 3376 3377 if (user) { 3378#ifdef CONFIG_RT_GROUP_SCHED 3379 /* 3380 * Do not allow realtime tasks into groups that have no runtime 3381 * assigned. 3382 */ 3383 if (rt_bandwidth_enabled() && rt_policy(policy) && 3384 task_group(p)->rt_bandwidth.rt_runtime == 0 && 3385 !task_group_is_autogroup(task_group(p))) { 3386 task_rq_unlock(rq, p, &flags); 3387 return -EPERM; 3388 } 3389#endif 3390#ifdef CONFIG_SMP 3391 if (dl_bandwidth_enabled() && dl_policy(policy)) { 3392 cpumask_t *span = rq->rd->span; 3393 3394 /* 3395 * Don't allow tasks with an affinity mask smaller than 3396 * the entire root_domain to become SCHED_DEADLINE. We 3397 * will also fail if there's no bandwidth available. 3398 */ 3399 if (!cpumask_subset(span, &p->cpus_allowed) || 3400 rq->rd->dl_bw.bw == 0) { 3401 task_rq_unlock(rq, p, &flags); 3402 return -EPERM; 3403 } 3404 } 3405#endif 3406 } 3407 3408 /* recheck policy now with rq lock held */ 3409 if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { 3410 policy = oldpolicy = -1; 3411 task_rq_unlock(rq, p, &flags); 3412 goto recheck; 3413 } 3414 3415 /* 3416 * If setscheduling to SCHED_DEADLINE (or changing the parameters 3417 * of a SCHED_DEADLINE task) we need to check if enough bandwidth 3418 * is available. 3419 */ 3420 if ((dl_policy(policy) || dl_task(p)) && dl_overflow(p, policy, attr)) { 3421 task_rq_unlock(rq, p, &flags); 3422 return -EBUSY; 3423 } 3424 3425 on_rq = p->on_rq; 3426 running = task_current(rq, p); 3427 if (on_rq) 3428 dequeue_task(rq, p, 0); 3429 if (running) 3430 p->sched_class->put_prev_task(rq, p); 3431 3432 p->sched_reset_on_fork = reset_on_fork; 3433 3434 oldprio = p->prio; 3435 prev_class = p->sched_class; 3436 __setscheduler(rq, p, attr); 3437 3438 if (running) 3439 p->sched_class->set_curr_task(rq); 3440 if (on_rq) 3441 enqueue_task(rq, p, 0); 3442 3443 check_class_changed(rq, p, prev_class, oldprio); 3444 task_rq_unlock(rq, p, &flags); 3445 3446 rt_mutex_adjust_pi(p); 3447 3448 return 0; 3449} 3450 3451/** 3452 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. 3453 * @p: the task in question. 3454 * @policy: new policy. 3455 * @param: structure containing the new RT priority. 3456 * 3457 * Return: 0 on success. An error code otherwise. 3458 * 3459 * NOTE that the task may be already dead. 3460 */ 3461int sched_setscheduler(struct task_struct *p, int policy, 3462 const struct sched_param *param) 3463{ 3464 struct sched_attr attr = { 3465 .sched_policy = policy, 3466 .sched_priority = param->sched_priority 3467 }; 3468 return __sched_setscheduler(p, &attr, true); 3469} 3470EXPORT_SYMBOL_GPL(sched_setscheduler); 3471 3472int sched_setattr(struct task_struct *p, const struct sched_attr *attr) 3473{ 3474 return __sched_setscheduler(p, attr, true); 3475} 3476EXPORT_SYMBOL_GPL(sched_setattr); 3477 3478/** 3479 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace. 3480 * @p: the task in question. 3481 * @policy: new policy. 3482 * @param: structure containing the new RT priority. 3483 * 3484 * Just like sched_setscheduler, only don't bother checking if the 3485 * current context has permission. For example, this is needed in 3486 * stop_machine(): we create temporary high priority worker threads, 3487 * but our caller might not have that capability. 3488 * 3489 * Return: 0 on success. An error code otherwise. 3490 */ 3491int sched_setscheduler_nocheck(struct task_struct *p, int policy, 3492 const struct sched_param *param) 3493{ 3494 struct sched_attr attr = { 3495 .sched_policy = policy, 3496 .sched_priority = param->sched_priority 3497 }; 3498 return __sched_setscheduler(p, &attr, false); 3499} 3500 3501static int 3502do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) 3503{ 3504 struct sched_param lparam; 3505 struct task_struct *p; 3506 int retval; 3507 3508 if (!param || pid < 0) 3509 return -EINVAL; 3510 if (copy_from_user(&lparam, param, sizeof(struct sched_param))) 3511 return -EFAULT; 3512 3513 rcu_read_lock(); 3514 retval = -ESRCH; 3515 p = find_process_by_pid(pid); 3516 if (p != NULL) 3517 retval = sched_setscheduler(p, policy, &lparam); 3518 rcu_read_unlock(); 3519 3520 return retval; 3521} 3522 3523/* 3524 * Mimics kernel/events/core.c perf_copy_attr(). 3525 */ 3526static int sched_copy_attr(struct sched_attr __user *uattr, 3527 struct sched_attr *attr) 3528{ 3529 u32 size; 3530 int ret; 3531 3532 if (!access_ok(VERIFY_WRITE, uattr, SCHED_ATTR_SIZE_VER0)) 3533 return -EFAULT; 3534 3535 /* 3536 * zero the full structure, so that a short copy will be nice. 3537 */ 3538 memset(attr, 0, sizeof(*attr)); 3539 3540 ret = get_user(size, &uattr->size); 3541 if (ret) 3542 return ret; 3543 3544 if (size > PAGE_SIZE) /* silly large */ 3545 goto err_size; 3546 3547 if (!size) /* abi compat */ 3548 size = SCHED_ATTR_SIZE_VER0; 3549 3550 if (size < SCHED_ATTR_SIZE_VER0) 3551 goto err_size; 3552 3553 /* 3554 * If we're handed a bigger struct than we know of, 3555 * ensure all the unknown bits are 0 - i.e. new 3556 * user-space does not rely on any kernel feature 3557 * extensions we dont know about yet. 3558 */ 3559 if (size > sizeof(*attr)) { 3560 unsigned char __user *addr; 3561 unsigned char __user *end; 3562 unsigned char val; 3563 3564 addr = (void __user *)uattr + sizeof(*attr); 3565 end = (void __user *)uattr + size; 3566 3567 for (; addr < end; addr++) { 3568 ret = get_user(val, addr); 3569 if (ret) 3570 return ret; 3571 if (val) 3572 goto err_size; 3573 } 3574 size = sizeof(*attr); 3575 } 3576 3577 ret = copy_from_user(attr, uattr, size); 3578 if (ret) 3579 return -EFAULT; 3580 3581 /* 3582 * XXX: do we want to be lenient like existing syscalls; or do we want 3583 * to be strict and return an error on out-of-bounds values? 3584 */ 3585 attr->sched_nice = clamp(attr->sched_nice, -20, 19); 3586 3587out: 3588 return ret; 3589 3590err_size: 3591 put_user(sizeof(*attr), &uattr->size); 3592 ret = -E2BIG; 3593 goto out; 3594} 3595 3596/** 3597 * sys_sched_setscheduler - set/change the scheduler policy and RT priority 3598 * @pid: the pid in question. 3599 * @policy: new policy. 3600 * @param: structure containing the new RT priority. 3601 * 3602 * Return: 0 on success. An error code otherwise. 3603 */ 3604SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy, 3605 struct sched_param __user *, param) 3606{ 3607 /* negative values for policy are not valid */ 3608 if (policy < 0) 3609 return -EINVAL; 3610 3611 return do_sched_setscheduler(pid, policy, param); 3612} 3613 3614/** 3615 * sys_sched_setparam - set/change the RT priority of a thread 3616 * @pid: the pid in question. 3617 * @param: structure containing the new RT priority. 3618 * 3619 * Return: 0 on success. An error code otherwise. 3620 */ 3621SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param) 3622{ 3623 return do_sched_setscheduler(pid, -1, param); 3624} 3625 3626/** 3627 * sys_sched_setattr - same as above, but with extended sched_attr 3628 * @pid: the pid in question. 3629 * @attr: structure containing the extended parameters. 3630 */ 3631SYSCALL_DEFINE2(sched_setattr, pid_t, pid, struct sched_attr __user *, uattr) 3632{ 3633 struct sched_attr attr; 3634 struct task_struct *p; 3635 int retval; 3636 3637 if (!uattr || pid < 0) 3638 return -EINVAL; 3639 3640 if (sched_copy_attr(uattr, &attr)) 3641 return -EFAULT; 3642 3643 rcu_read_lock(); 3644 retval = -ESRCH; 3645 p = find_process_by_pid(pid); 3646 if (p != NULL) 3647 retval = sched_setattr(p, &attr); 3648 rcu_read_unlock(); 3649 3650 return retval; 3651} 3652 3653/** 3654 * sys_sched_getscheduler - get the policy (scheduling class) of a thread 3655 * @pid: the pid in question. 3656 * 3657 * Return: On success, the policy of the thread. Otherwise, a negative error 3658 * code. 3659 */ 3660SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid) 3661{ 3662 struct task_struct *p; 3663 int retval; 3664 3665 if (pid < 0) 3666 return -EINVAL; 3667 3668 retval = -ESRCH; 3669 rcu_read_lock(); 3670 p = find_process_by_pid(pid); 3671 if (p) { 3672 retval = security_task_getscheduler(p); 3673 if (!retval) 3674 retval = p->policy 3675 | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0); 3676 } 3677 rcu_read_unlock(); 3678 return retval; 3679} 3680 3681/** 3682 * sys_sched_getparam - get the RT priority of a thread 3683 * @pid: the pid in question. 3684 * @param: structure containing the RT priority. 3685 * 3686 * Return: On success, 0 and the RT priority is in @param. Otherwise, an error 3687 * code. 3688 */ 3689SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param) 3690{ 3691 struct sched_param lp; 3692 struct task_struct *p; 3693 int retval; 3694 3695 if (!param || pid < 0) 3696 return -EINVAL; 3697 3698 rcu_read_lock(); 3699 p = find_process_by_pid(pid); 3700 retval = -ESRCH; 3701 if (!p) 3702 goto out_unlock; 3703 3704 retval = security_task_getscheduler(p); 3705 if (retval) 3706 goto out_unlock; 3707 3708 if (task_has_dl_policy(p)) { 3709 retval = -EINVAL; 3710 goto out_unlock; 3711 } 3712 lp.sched_priority = p->rt_priority; 3713 rcu_read_unlock(); 3714 3715 /* 3716 * This one might sleep, we cannot do it with a spinlock held ... 3717 */ 3718 retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; 3719 3720 return retval; 3721 3722out_unlock: 3723 rcu_read_unlock(); 3724 return retval; 3725} 3726 3727static int sched_read_attr(struct sched_attr __user *uattr, 3728 struct sched_attr *attr, 3729 unsigned int usize) 3730{ 3731 int ret; 3732 3733 if (!access_ok(VERIFY_WRITE, uattr, usize)) 3734 return -EFAULT; 3735 3736 /* 3737 * If we're handed a smaller struct than we know of, 3738 * ensure all the unknown bits are 0 - i.e. old 3739 * user-space does not get uncomplete information. 3740 */ 3741 if (usize < sizeof(*attr)) { 3742 unsigned char *addr; 3743 unsigned char *end; 3744 3745 addr = (void *)attr + usize; 3746 end = (void *)attr + sizeof(*attr); 3747 3748 for (; addr < end; addr++) { 3749 if (*addr) 3750 goto err_size; 3751 } 3752 3753 attr->size = usize; 3754 } 3755 3756 ret = copy_to_user(uattr, attr, usize); 3757 if (ret) 3758 return -EFAULT; 3759 3760out: 3761 return ret; 3762 3763err_size: 3764 ret = -E2BIG; 3765 goto out; 3766} 3767 3768/** 3769 * sys_sched_getattr - similar to sched_getparam, but with sched_attr 3770 * @pid: the pid in question. 3771 * @attr: structure containing the extended parameters. 3772 * @size: sizeof(attr) for fwd/bwd comp. 3773 */ 3774SYSCALL_DEFINE3(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr, 3775 unsigned int, size) 3776{ 3777 struct sched_attr attr = { 3778 .size = sizeof(struct sched_attr), 3779 }; 3780 struct task_struct *p; 3781 int retval; 3782 3783 if (!uattr || pid < 0 || size > PAGE_SIZE || 3784 size < SCHED_ATTR_SIZE_VER0) 3785 return -EINVAL; 3786 3787 rcu_read_lock(); 3788 p = find_process_by_pid(pid); 3789 retval = -ESRCH; 3790 if (!p) 3791 goto out_unlock; 3792 3793 retval = security_task_getscheduler(p); 3794 if (retval) 3795 goto out_unlock; 3796 3797 attr.sched_policy = p->policy; 3798 if (task_has_dl_policy(p)) 3799 __getparam_dl(p, &attr); 3800 else if (task_has_rt_policy(p)) 3801 attr.sched_priority = p->rt_priority; 3802 else 3803 attr.sched_nice = TASK_NICE(p); 3804 3805 rcu_read_unlock(); 3806 3807 retval = sched_read_attr(uattr, &attr, size); 3808 return retval; 3809 3810out_unlock: 3811 rcu_read_unlock(); 3812 return retval; 3813} 3814 3815long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) 3816{ 3817 cpumask_var_t cpus_allowed, new_mask; 3818 struct task_struct *p; 3819 int retval; 3820 3821 rcu_read_lock(); 3822 3823 p = find_process_by_pid(pid); 3824 if (!p) { 3825 rcu_read_unlock(); 3826 return -ESRCH; 3827 } 3828 3829 /* Prevent p going away */ 3830 get_task_struct(p); 3831 rcu_read_unlock(); 3832 3833 if (p->flags & PF_NO_SETAFFINITY) { 3834 retval = -EINVAL; 3835 goto out_put_task; 3836 } 3837 if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) { 3838 retval = -ENOMEM; 3839 goto out_put_task; 3840 } 3841 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) { 3842 retval = -ENOMEM; 3843 goto out_free_cpus_allowed; 3844 } 3845 retval = -EPERM; 3846 if (!check_same_owner(p)) { 3847 rcu_read_lock(); 3848 if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) { 3849 rcu_read_unlock(); 3850 goto out_unlock; 3851 } 3852 rcu_read_unlock(); 3853 } 3854 3855 retval = security_task_setscheduler(p); 3856 if (retval) 3857 goto out_unlock; 3858 3859 3860 cpuset_cpus_allowed(p, cpus_allowed); 3861 cpumask_and(new_mask, in_mask, cpus_allowed); 3862 3863 /* 3864 * Since bandwidth control happens on root_domain basis, 3865 * if admission test is enabled, we only admit -deadline 3866 * tasks allowed to run on all the CPUs in the task's 3867 * root_domain. 3868 */ 3869#ifdef CONFIG_SMP 3870 if (task_has_dl_policy(p)) { 3871 const struct cpumask *span = task_rq(p)->rd->span; 3872 3873 if (dl_bandwidth_enabled() && !cpumask_subset(span, new_mask)) { 3874 retval = -EBUSY; 3875 goto out_unlock; 3876 } 3877 } 3878#endif 3879again: 3880 retval = set_cpus_allowed_ptr(p, new_mask); 3881 3882 if (!retval) { 3883 cpuset_cpus_allowed(p, cpus_allowed); 3884 if (!cpumask_subset(new_mask, cpus_allowed)) { 3885 /* 3886 * We must have raced with a concurrent cpuset 3887 * update. Just reset the cpus_allowed to the 3888 * cpuset's cpus_allowed 3889 */ 3890 cpumask_copy(new_mask, cpus_allowed); 3891 goto again; 3892 } 3893 } 3894out_unlock: 3895 free_cpumask_var(new_mask); 3896out_free_cpus_allowed: 3897 free_cpumask_var(cpus_allowed); 3898out_put_task: 3899 put_task_struct(p); 3900 return retval; 3901} 3902 3903static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, 3904 struct cpumask *new_mask) 3905{ 3906 if (len < cpumask_size()) 3907 cpumask_clear(new_mask); 3908 else if (len > cpumask_size()) 3909 len = cpumask_size(); 3910 3911 return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; 3912} 3913 3914/** 3915 * sys_sched_setaffinity - set the cpu affinity of a process 3916 * @pid: pid of the process 3917 * @len: length in bytes of the bitmask pointed to by user_mask_ptr 3918 * @user_mask_ptr: user-space pointer to the new cpu mask 3919 * 3920 * Return: 0 on success. An error code otherwise. 3921 */ 3922SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len, 3923 unsigned long __user *, user_mask_ptr) 3924{ 3925 cpumask_var_t new_mask; 3926 int retval; 3927 3928 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) 3929 return -ENOMEM; 3930 3931 retval = get_user_cpu_mask(user_mask_ptr, len, new_mask); 3932 if (retval == 0) 3933 retval = sched_setaffinity(pid, new_mask); 3934 free_cpumask_var(new_mask); 3935 return retval; 3936} 3937 3938long sched_getaffinity(pid_t pid, struct cpumask *mask) 3939{ 3940 struct task_struct *p; 3941 unsigned long flags; 3942 int retval; 3943 3944 rcu_read_lock(); 3945 3946 retval = -ESRCH; 3947 p = find_process_by_pid(pid); 3948 if (!p) 3949 goto out_unlock; 3950 3951 retval = security_task_getscheduler(p); 3952 if (retval) 3953 goto out_unlock; 3954 3955 raw_spin_lock_irqsave(&p->pi_lock, flags); 3956 cpumask_and(mask, &p->cpus_allowed, cpu_active_mask); 3957 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 3958 3959out_unlock: 3960 rcu_read_unlock(); 3961 3962 return retval; 3963} 3964 3965/** 3966 * sys_sched_getaffinity - get the cpu affinity of a process 3967 * @pid: pid of the process 3968 * @len: length in bytes of the bitmask pointed to by user_mask_ptr 3969 * @user_mask_ptr: user-space pointer to hold the current cpu mask 3970 * 3971 * Return: 0 on success. An error code otherwise. 3972 */ 3973SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len, 3974 unsigned long __user *, user_mask_ptr) 3975{ 3976 int ret; 3977 cpumask_var_t mask; 3978 3979 if ((len * BITS_PER_BYTE) < nr_cpu_ids) 3980 return -EINVAL; 3981 if (len & (sizeof(unsigned long)-1)) 3982 return -EINVAL; 3983 3984 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) 3985 return -ENOMEM; 3986 3987 ret = sched_getaffinity(pid, mask); 3988 if (ret == 0) { 3989 size_t retlen = min_t(size_t, len, cpumask_size()); 3990 3991 if (copy_to_user(user_mask_ptr, mask, retlen)) 3992 ret = -EFAULT; 3993 else 3994 ret = retlen; 3995 } 3996 free_cpumask_var(mask); 3997 3998 return ret; 3999} 4000 4001/** 4002 * sys_sched_yield - yield the current processor to other threads. 4003 * 4004 * This function yields the current CPU to other tasks. If there are no 4005 * other threads running on this CPU then this function will return. 4006 * 4007 * Return: 0. 4008 */ 4009SYSCALL_DEFINE0(sched_yield) 4010{ 4011 struct rq *rq = this_rq_lock(); 4012 4013 schedstat_inc(rq, yld_count); 4014 current->sched_class->yield_task(rq); 4015 4016 /* 4017 * Since we are going to call schedule() anyway, there's 4018 * no need to preempt or enable interrupts: 4019 */ 4020 __release(rq->lock); 4021 spin_release(&rq->lock.dep_map, 1, _THIS_IP_); 4022 do_raw_spin_unlock(&rq->lock); 4023 sched_preempt_enable_no_resched(); 4024 4025 schedule(); 4026 4027 return 0; 4028} 4029 4030static void __cond_resched(void) 4031{ 4032 __preempt_count_add(PREEMPT_ACTIVE); 4033 __schedule(); 4034 __preempt_count_sub(PREEMPT_ACTIVE); 4035} 4036 4037int __sched _cond_resched(void) 4038{ 4039 if (should_resched()) { 4040 __cond_resched(); 4041 return 1; 4042 } 4043 return 0; 4044} 4045EXPORT_SYMBOL(_cond_resched); 4046 4047/* 4048 * __cond_resched_lock() - if a reschedule is pending, drop the given lock, 4049 * call schedule, and on return reacquire the lock. 4050 * 4051 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level 4052 * operations here to prevent schedule() from being called twice (once via 4053 * spin_unlock(), once by hand). 4054 */ 4055int __cond_resched_lock(spinlock_t *lock) 4056{ 4057 int resched = should_resched(); 4058 int ret = 0; 4059 4060 lockdep_assert_held(lock); 4061 4062 if (spin_needbreak(lock) || resched) { 4063 spin_unlock(lock); 4064 if (resched) 4065 __cond_resched(); 4066 else 4067 cpu_relax(); 4068 ret = 1; 4069 spin_lock(lock); 4070 } 4071 return ret; 4072} 4073EXPORT_SYMBOL(__cond_resched_lock); 4074 4075int __sched __cond_resched_softirq(void) 4076{ 4077 BUG_ON(!in_softirq()); 4078 4079 if (should_resched()) { 4080 local_bh_enable(); 4081 __cond_resched(); 4082 local_bh_disable(); 4083 return 1; 4084 } 4085 return 0; 4086} 4087EXPORT_SYMBOL(__cond_resched_softirq); 4088 4089/** 4090 * yield - yield the current processor to other threads. 4091 * 4092 * Do not ever use this function, there's a 99% chance you're doing it wrong. 4093 * 4094 * The scheduler is at all times free to pick the calling task as the most 4095 * eligible task to run, if removing the yield() call from your code breaks 4096 * it, its already broken. 4097 * 4098 * Typical broken usage is: 4099 * 4100 * while (!event) 4101 * yield(); 4102 * 4103 * where one assumes that yield() will let 'the other' process run that will 4104 * make event true. If the current task is a SCHED_FIFO task that will never 4105 * happen. Never use yield() as a progress guarantee!! 4106 * 4107 * If you want to use yield() to wait for something, use wait_event(). 4108 * If you want to use yield() to be 'nice' for others, use cond_resched(). 4109 * If you still want to use yield(), do not! 4110 */ 4111void __sched yield(void) 4112{ 4113 set_current_state(TASK_RUNNING); 4114 sys_sched_yield(); 4115} 4116EXPORT_SYMBOL(yield); 4117 4118/** 4119 * yield_to - yield the current processor to another thread in 4120 * your thread group, or accelerate that thread toward the 4121 * processor it's on. 4122 * @p: target task 4123 * @preempt: whether task preemption is allowed or not 4124 * 4125 * It's the caller's job to ensure that the target task struct 4126 * can't go away on us before we can do any checks. 4127 * 4128 * Return: 4129 * true (>0) if we indeed boosted the target task. 4130 * false (0) if we failed to boost the target. 4131 * -ESRCH if there's no task to yield to. 4132 */ 4133bool __sched yield_to(struct task_struct *p, bool preempt) 4134{ 4135 struct task_struct *curr = current; 4136 struct rq *rq, *p_rq; 4137 unsigned long flags; 4138 int yielded = 0; 4139 4140 local_irq_save(flags); 4141 rq = this_rq(); 4142 4143again: 4144 p_rq = task_rq(p); 4145 /* 4146 * If we're the only runnable task on the rq and target rq also 4147 * has only one task, there's absolutely no point in yielding. 4148 */ 4149 if (rq->nr_running == 1 && p_rq->nr_running == 1) { 4150 yielded = -ESRCH; 4151 goto out_irq; 4152 } 4153 4154 double_rq_lock(rq, p_rq); 4155 if (task_rq(p) != p_rq) { 4156 double_rq_unlock(rq, p_rq); 4157 goto again; 4158 } 4159 4160 if (!curr->sched_class->yield_to_task) 4161 goto out_unlock; 4162 4163 if (curr->sched_class != p->sched_class) 4164 goto out_unlock; 4165 4166 if (task_running(p_rq, p) || p->state) 4167 goto out_unlock; 4168 4169 yielded = curr->sched_class->yield_to_task(rq, p, preempt); 4170 if (yielded) { 4171 schedstat_inc(rq, yld_count); 4172 /* 4173 * Make p's CPU reschedule; pick_next_entity takes care of 4174 * fairness. 4175 */ 4176 if (preempt && rq != p_rq) 4177 resched_task(p_rq->curr); 4178 } 4179 4180out_unlock: 4181 double_rq_unlock(rq, p_rq); 4182out_irq: 4183 local_irq_restore(flags); 4184 4185 if (yielded > 0) 4186 schedule(); 4187 4188 return yielded; 4189} 4190EXPORT_SYMBOL_GPL(yield_to); 4191 4192/* 4193 * This task is about to go to sleep on IO. Increment rq->nr_iowait so 4194 * that process accounting knows that this is a task in IO wait state. 4195 */ 4196void __sched io_schedule(void) 4197{ 4198 struct rq *rq = raw_rq(); 4199 4200 delayacct_blkio_start(); 4201 atomic_inc(&rq->nr_iowait); 4202 blk_flush_plug(current); 4203 current->in_iowait = 1; 4204 schedule(); 4205 current->in_iowait = 0; 4206 atomic_dec(&rq->nr_iowait); 4207 delayacct_blkio_end(); 4208} 4209EXPORT_SYMBOL(io_schedule); 4210 4211long __sched io_schedule_timeout(long timeout) 4212{ 4213 struct rq *rq = raw_rq(); 4214 long ret; 4215 4216 delayacct_blkio_start(); 4217 atomic_inc(&rq->nr_iowait); 4218 blk_flush_plug(current); 4219 current->in_iowait = 1; 4220 ret = schedule_timeout(timeout); 4221 current->in_iowait = 0; 4222 atomic_dec(&rq->nr_iowait); 4223 delayacct_blkio_end(); 4224 return ret; 4225} 4226 4227/** 4228 * sys_sched_get_priority_max - return maximum RT priority. 4229 * @policy: scheduling class. 4230 * 4231 * Return: On success, this syscall returns the maximum 4232 * rt_priority that can be used by a given scheduling class. 4233 * On failure, a negative error code is returned. 4234 */ 4235SYSCALL_DEFINE1(sched_get_priority_max, int, policy) 4236{ 4237 int ret = -EINVAL; 4238 4239 switch (policy) { 4240 case SCHED_FIFO: 4241 case SCHED_RR: 4242 ret = MAX_USER_RT_PRIO-1; 4243 break; 4244 case SCHED_DEADLINE: 4245 case SCHED_NORMAL: 4246 case SCHED_BATCH: 4247 case SCHED_IDLE: 4248 ret = 0; 4249 break; 4250 } 4251 return ret; 4252} 4253 4254/** 4255 * sys_sched_get_priority_min - return minimum RT priority. 4256 * @policy: scheduling class. 4257 * 4258 * Return: On success, this syscall returns the minimum 4259 * rt_priority that can be used by a given scheduling class. 4260 * On failure, a negative error code is returned. 4261 */ 4262SYSCALL_DEFINE1(sched_get_priority_min, int, policy) 4263{ 4264 int ret = -EINVAL; 4265 4266 switch (policy) { 4267 case SCHED_FIFO: 4268 case SCHED_RR: 4269 ret = 1; 4270 break; 4271 case SCHED_DEADLINE: 4272 case SCHED_NORMAL: 4273 case SCHED_BATCH: 4274 case SCHED_IDLE: 4275 ret = 0; 4276 } 4277 return ret; 4278} 4279 4280/** 4281 * sys_sched_rr_get_interval - return the default timeslice of a process. 4282 * @pid: pid of the process. 4283 * @interval: userspace pointer to the timeslice value. 4284 * 4285 * this syscall writes the default timeslice value of a given process 4286 * into the user-space timespec buffer. A value of '0' means infinity. 4287 * 4288 * Return: On success, 0 and the timeslice is in @interval. Otherwise, 4289 * an error code. 4290 */ 4291SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid, 4292 struct timespec __user *, interval) 4293{ 4294 struct task_struct *p; 4295 unsigned int time_slice; 4296 unsigned long flags; 4297 struct rq *rq; 4298 int retval; 4299 struct timespec t; 4300 4301 if (pid < 0) 4302 return -EINVAL; 4303 4304 retval = -ESRCH; 4305 rcu_read_lock(); 4306 p = find_process_by_pid(pid); 4307 if (!p) 4308 goto out_unlock; 4309 4310 retval = security_task_getscheduler(p); 4311 if (retval) 4312 goto out_unlock; 4313 4314 rq = task_rq_lock(p, &flags); 4315 time_slice = p->sched_class->get_rr_interval(rq, p); 4316 task_rq_unlock(rq, p, &flags); 4317 4318 rcu_read_unlock(); 4319 jiffies_to_timespec(time_slice, &t); 4320 retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; 4321 return retval; 4322 4323out_unlock: 4324 rcu_read_unlock(); 4325 return retval; 4326} 4327 4328static const char stat_nam[] = TASK_STATE_TO_CHAR_STR; 4329 4330void sched_show_task(struct task_struct *p) 4331{ 4332 unsigned long free = 0; 4333 int ppid; 4334 unsigned state; 4335 4336 state = p->state ? __ffs(p->state) + 1 : 0; 4337 printk(KERN_INFO "%-15.15s %c", p->comm, 4338 state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); 4339#if BITS_PER_LONG == 32 4340 if (state == TASK_RUNNING) 4341 printk(KERN_CONT " running "); 4342 else 4343 printk(KERN_CONT " %08lx ", thread_saved_pc(p)); 4344#else 4345 if (state == TASK_RUNNING) 4346 printk(KERN_CONT " running task "); 4347 else 4348 printk(KERN_CONT " %016lx ", thread_saved_pc(p)); 4349#endif 4350#ifdef CONFIG_DEBUG_STACK_USAGE 4351 free = stack_not_used(p); 4352#endif 4353 rcu_read_lock(); 4354 ppid = task_pid_nr(rcu_dereference(p->real_parent)); 4355 rcu_read_unlock(); 4356 printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free, 4357 task_pid_nr(p), ppid, 4358 (unsigned long)task_thread_info(p)->flags); 4359 4360 print_worker_info(KERN_INFO, p); 4361 show_stack(p, NULL); 4362} 4363 4364void show_state_filter(unsigned long state_filter) 4365{ 4366 struct task_struct *g, *p; 4367 4368#if BITS_PER_LONG == 32 4369 printk(KERN_INFO 4370 " task PC stack pid father\n"); 4371#else 4372 printk(KERN_INFO 4373 " task PC stack pid father\n"); 4374#endif 4375 rcu_read_lock(); 4376 do_each_thread(g, p) { 4377 /* 4378 * reset the NMI-timeout, listing all files on a slow 4379 * console might take a lot of time: 4380 */ 4381 touch_nmi_watchdog(); 4382 if (!state_filter || (p->state & state_filter)) 4383 sched_show_task(p); 4384 } while_each_thread(g, p); 4385 4386 touch_all_softlockup_watchdogs(); 4387 4388#ifdef CONFIG_SCHED_DEBUG 4389 sysrq_sched_debug_show(); 4390#endif 4391 rcu_read_unlock(); 4392 /* 4393 * Only show locks if all tasks are dumped: 4394 */ 4395 if (!state_filter) 4396 debug_show_all_locks(); 4397} 4398 4399void init_idle_bootup_task(struct task_struct *idle) 4400{ 4401 idle->sched_class = &idle_sched_class; 4402} 4403 4404/** 4405 * init_idle - set up an idle thread for a given CPU 4406 * @idle: task in question 4407 * @cpu: cpu the idle task belongs to 4408 * 4409 * NOTE: this function does not set the idle thread's NEED_RESCHED 4410 * flag, to make booting more robust. 4411 */ 4412void init_idle(struct task_struct *idle, int cpu) 4413{ 4414 struct rq *rq = cpu_rq(cpu); 4415 unsigned long flags; 4416 4417 raw_spin_lock_irqsave(&rq->lock, flags); 4418 4419 __sched_fork(0, idle); 4420 idle->state = TASK_RUNNING; 4421 idle->se.exec_start = sched_clock(); 4422 4423 do_set_cpus_allowed(idle, cpumask_of(cpu)); 4424 /* 4425 * We're having a chicken and egg problem, even though we are 4426 * holding rq->lock, the cpu isn't yet set to this cpu so the 4427 * lockdep check in task_group() will fail. 4428 * 4429 * Similar case to sched_fork(). / Alternatively we could 4430 * use task_rq_lock() here and obtain the other rq->lock. 4431 * 4432 * Silence PROVE_RCU 4433 */ 4434 rcu_read_lock(); 4435 __set_task_cpu(idle, cpu); 4436 rcu_read_unlock(); 4437 4438 rq->curr = rq->idle = idle; 4439#if defined(CONFIG_SMP) 4440 idle->on_cpu = 1; 4441#endif 4442 raw_spin_unlock_irqrestore(&rq->lock, flags); 4443 4444 /* Set the preempt count _outside_ the spinlocks! */ 4445 init_idle_preempt_count(idle, cpu); 4446 4447 /* 4448 * The idle tasks have their own, simple scheduling class: 4449 */ 4450 idle->sched_class = &idle_sched_class; 4451 ftrace_graph_init_idle_task(idle, cpu); 4452 vtime_init_idle(idle, cpu); 4453#if defined(CONFIG_SMP) 4454 sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu); 4455#endif 4456} 4457 4458#ifdef CONFIG_SMP 4459void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) 4460{ 4461 if (p->sched_class && p->sched_class->set_cpus_allowed) 4462 p->sched_class->set_cpus_allowed(p, new_mask); 4463 4464 cpumask_copy(&p->cpus_allowed, new_mask); 4465 p->nr_cpus_allowed = cpumask_weight(new_mask); 4466} 4467 4468/* 4469 * This is how migration works: 4470 * 4471 * 1) we invoke migration_cpu_stop() on the target CPU using 4472 * stop_one_cpu(). 4473 * 2) stopper starts to run (implicitly forcing the migrated thread 4474 * off the CPU) 4475 * 3) it checks whether the migrated task is still in the wrong runqueue. 4476 * 4) if it's in the wrong runqueue then the migration thread removes 4477 * it and puts it into the right queue. 4478 * 5) stopper completes and stop_one_cpu() returns and the migration 4479 * is done. 4480 */ 4481 4482/* 4483 * Change a given task's CPU affinity. Migrate the thread to a 4484 * proper CPU and schedule it away if the CPU it's executing on 4485 * is removed from the allowed bitmask. 4486 * 4487 * NOTE: the caller must have a valid reference to the task, the 4488 * task must not exit() & deallocate itself prematurely. The 4489 * call is not atomic; no spinlocks may be held. 4490 */ 4491int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) 4492{ 4493 unsigned long flags; 4494 struct rq *rq; 4495 unsigned int dest_cpu; 4496 int ret = 0; 4497 4498 rq = task_rq_lock(p, &flags); 4499 4500 if (cpumask_equal(&p->cpus_allowed, new_mask)) 4501 goto out; 4502 4503 if (!cpumask_intersects(new_mask, cpu_active_mask)) { 4504 ret = -EINVAL; 4505 goto out; 4506 } 4507 4508 do_set_cpus_allowed(p, new_mask); 4509 4510 /* Can the task run on the task's current CPU? If so, we're done */ 4511 if (cpumask_test_cpu(task_cpu(p), new_mask)) 4512 goto out; 4513 4514 dest_cpu = cpumask_any_and(cpu_active_mask, new_mask); 4515 if (p->on_rq) { 4516 struct migration_arg arg = { p, dest_cpu }; 4517 /* Need help from migration thread: drop lock and wait. */ 4518 task_rq_unlock(rq, p, &flags); 4519 stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg); 4520 tlb_migrate_finish(p->mm); 4521 return 0; 4522 } 4523out: 4524 task_rq_unlock(rq, p, &flags); 4525 4526 return ret; 4527} 4528EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr); 4529 4530/* 4531 * Move (not current) task off this cpu, onto dest cpu. We're doing 4532 * this because either it can't run here any more (set_cpus_allowed() 4533 * away from this CPU, or CPU going down), or because we're 4534 * attempting to rebalance this task on exec (sched_exec). 4535 * 4536 * So we race with normal scheduler movements, but that's OK, as long 4537 * as the task is no longer on this CPU. 4538 * 4539 * Returns non-zero if task was successfully migrated. 4540 */ 4541static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) 4542{ 4543 struct rq *rq_dest, *rq_src; 4544 int ret = 0; 4545 4546 if (unlikely(!cpu_active(dest_cpu))) 4547 return ret; 4548 4549 rq_src = cpu_rq(src_cpu); 4550 rq_dest = cpu_rq(dest_cpu); 4551 4552 raw_spin_lock(&p->pi_lock); 4553 double_rq_lock(rq_src, rq_dest); 4554 /* Already moved. */ 4555 if (task_cpu(p) != src_cpu) 4556 goto done; 4557 /* Affinity changed (again). */ 4558 if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) 4559 goto fail; 4560 4561 /* 4562 * If we're not on a rq, the next wake-up will ensure we're 4563 * placed properly. 4564 */ 4565 if (p->on_rq) { 4566 dequeue_task(rq_src, p, 0); 4567 set_task_cpu(p, dest_cpu); 4568 enqueue_task(rq_dest, p, 0); 4569 check_preempt_curr(rq_dest, p, 0); 4570 } 4571done: 4572 ret = 1; 4573fail: 4574 double_rq_unlock(rq_src, rq_dest); 4575 raw_spin_unlock(&p->pi_lock); 4576 return ret; 4577} 4578 4579#ifdef CONFIG_NUMA_BALANCING 4580/* Migrate current task p to target_cpu */ 4581int migrate_task_to(struct task_struct *p, int target_cpu) 4582{ 4583 struct migration_arg arg = { p, target_cpu }; 4584 int curr_cpu = task_cpu(p); 4585 4586 if (curr_cpu == target_cpu) 4587 return 0; 4588 4589 if (!cpumask_test_cpu(target_cpu, tsk_cpus_allowed(p))) 4590 return -EINVAL; 4591 4592 /* TODO: This is not properly updating schedstats */ 4593 4594 return stop_one_cpu(curr_cpu, migration_cpu_stop, &arg); 4595} 4596 4597/* 4598 * Requeue a task on a given node and accurately track the number of NUMA 4599 * tasks on the runqueues 4600 */ 4601void sched_setnuma(struct task_struct *p, int nid) 4602{ 4603 struct rq *rq; 4604 unsigned long flags; 4605 bool on_rq, running; 4606 4607 rq = task_rq_lock(p, &flags); 4608 on_rq = p->on_rq; 4609 running = task_current(rq, p); 4610 4611 if (on_rq) 4612 dequeue_task(rq, p, 0); 4613 if (running) 4614 p->sched_class->put_prev_task(rq, p); 4615 4616 p->numa_preferred_nid = nid; 4617 4618 if (running) 4619 p->sched_class->set_curr_task(rq); 4620 if (on_rq) 4621 enqueue_task(rq, p, 0); 4622 task_rq_unlock(rq, p, &flags); 4623} 4624#endif 4625 4626/* 4627 * migration_cpu_stop - this will be executed by a highprio stopper thread 4628 * and performs thread migration by bumping thread off CPU then 4629 * 'pushing' onto another runqueue. 4630 */ 4631static int migration_cpu_stop(void *data) 4632{ 4633 struct migration_arg *arg = data; 4634 4635 /* 4636 * The original target cpu might have gone down and we might 4637 * be on another cpu but it doesn't matter. 4638 */ 4639 local_irq_disable(); 4640 __migrate_task(arg->task, raw_smp_processor_id(), arg->dest_cpu); 4641 local_irq_enable(); 4642 return 0; 4643} 4644 4645#ifdef CONFIG_HOTPLUG_CPU 4646 4647/* 4648 * Ensures that the idle task is using init_mm right before its cpu goes 4649 * offline. 4650 */ 4651void idle_task_exit(void) 4652{ 4653 struct mm_struct *mm = current->active_mm; 4654 4655 BUG_ON(cpu_online(smp_processor_id())); 4656 4657 if (mm != &init_mm) 4658 switch_mm(mm, &init_mm, current); 4659 mmdrop(mm); 4660} 4661 4662/* 4663 * Since this CPU is going 'away' for a while, fold any nr_active delta 4664 * we might have. Assumes we're called after migrate_tasks() so that the 4665 * nr_active count is stable. 4666 * 4667 * Also see the comment "Global load-average calculations". 4668 */ 4669static void calc_load_migrate(struct rq *rq) 4670{ 4671 long delta = calc_load_fold_active(rq); 4672 if (delta) 4673 atomic_long_add(delta, &calc_load_tasks); 4674} 4675 4676/* 4677 * Migrate all tasks from the rq, sleeping tasks will be migrated by 4678 * try_to_wake_up()->select_task_rq(). 4679 * 4680 * Called with rq->lock held even though we'er in stop_machine() and 4681 * there's no concurrency possible, we hold the required locks anyway 4682 * because of lock validation efforts. 4683 */ 4684static void migrate_tasks(unsigned int dead_cpu) 4685{ 4686 struct rq *rq = cpu_rq(dead_cpu); 4687 struct task_struct *next, *stop = rq->stop; 4688 int dest_cpu; 4689 4690 /* 4691 * Fudge the rq selection such that the below task selection loop 4692 * doesn't get stuck on the currently eligible stop task. 4693 * 4694 * We're currently inside stop_machine() and the rq is either stuck 4695 * in the stop_machine_cpu_stop() loop, or we're executing this code, 4696 * either way we should never end up calling schedule() until we're 4697 * done here. 4698 */ 4699 rq->stop = NULL; 4700 4701 /* 4702 * put_prev_task() and pick_next_task() sched 4703 * class method both need to have an up-to-date 4704 * value of rq->clock[_task] 4705 */ 4706 update_rq_clock(rq); 4707 4708 for ( ; ; ) { 4709 /* 4710 * There's this thread running, bail when that's the only 4711 * remaining thread. 4712 */ 4713 if (rq->nr_running == 1) 4714 break; 4715 4716 next = pick_next_task(rq); 4717 BUG_ON(!next); 4718 next->sched_class->put_prev_task(rq, next); 4719 4720 /* Find suitable destination for @next, with force if needed. */ 4721 dest_cpu = select_fallback_rq(dead_cpu, next); 4722 raw_spin_unlock(&rq->lock); 4723 4724 __migrate_task(next, dead_cpu, dest_cpu); 4725 4726 raw_spin_lock(&rq->lock); 4727 } 4728 4729 rq->stop = stop; 4730} 4731 4732#endif /* CONFIG_HOTPLUG_CPU */ 4733 4734#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL) 4735 4736static struct ctl_table sd_ctl_dir[] = { 4737 { 4738 .procname = "sched_domain", 4739 .mode = 0555, 4740 }, 4741 {} 4742}; 4743 4744static struct ctl_table sd_ctl_root[] = { 4745 { 4746 .procname = "kernel", 4747 .mode = 0555, 4748 .child = sd_ctl_dir, 4749 }, 4750 {} 4751}; 4752 4753static struct ctl_table *sd_alloc_ctl_entry(int n) 4754{ 4755 struct ctl_table *entry = 4756 kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL); 4757 4758 return entry; 4759} 4760 4761static void sd_free_ctl_entry(struct ctl_table **tablep) 4762{ 4763 struct ctl_table *entry; 4764 4765 /* 4766 * In the intermediate directories, both the child directory and 4767 * procname are dynamically allocated and could fail but the mode 4768 * will always be set. In the lowest directory the names are 4769 * static strings and all have proc handlers. 4770 */ 4771 for (entry = *tablep; entry->mode; entry++) { 4772 if (entry->child) 4773 sd_free_ctl_entry(&entry->child); 4774 if (entry->proc_handler == NULL) 4775 kfree(entry->procname); 4776 } 4777 4778 kfree(*tablep); 4779 *tablep = NULL; 4780} 4781 4782static int min_load_idx = 0; 4783static int max_load_idx = CPU_LOAD_IDX_MAX-1; 4784 4785static void 4786set_table_entry(struct ctl_table *entry, 4787 const char *procname, void *data, int maxlen, 4788 umode_t mode, proc_handler *proc_handler, 4789 bool load_idx) 4790{ 4791 entry->procname = procname; 4792 entry->data = data; 4793 entry->maxlen = maxlen; 4794 entry->mode = mode; 4795 entry->proc_handler = proc_handler; 4796 4797 if (load_idx) { 4798 entry->extra1 = &min_load_idx; 4799 entry->extra2 = &max_load_idx; 4800 } 4801} 4802 4803static struct ctl_table * 4804sd_alloc_ctl_domain_table(struct sched_domain *sd) 4805{ 4806 struct ctl_table *table = sd_alloc_ctl_entry(13); 4807 4808 if (table == NULL) 4809 return NULL; 4810 4811 set_table_entry(&table[0], "min_interval", &sd->min_interval, 4812 sizeof(long), 0644, proc_doulongvec_minmax, false); 4813 set_table_entry(&table[1], "max_interval", &sd->max_interval, 4814 sizeof(long), 0644, proc_doulongvec_minmax, false); 4815 set_table_entry(&table[2], "busy_idx", &sd->busy_idx, 4816 sizeof(int), 0644, proc_dointvec_minmax, true); 4817 set_table_entry(&table[3], "idle_idx", &sd->idle_idx, 4818 sizeof(int), 0644, proc_dointvec_minmax, true); 4819 set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx, 4820 sizeof(int), 0644, proc_dointvec_minmax, true); 4821 set_table_entry(&table[5], "wake_idx", &sd->wake_idx, 4822 sizeof(int), 0644, proc_dointvec_minmax, true); 4823 set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx, 4824 sizeof(int), 0644, proc_dointvec_minmax, true); 4825 set_table_entry(&table[7], "busy_factor", &sd->busy_factor, 4826 sizeof(int), 0644, proc_dointvec_minmax, false); 4827 set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct, 4828 sizeof(int), 0644, proc_dointvec_minmax, false); 4829 set_table_entry(&table[9], "cache_nice_tries", 4830 &sd->cache_nice_tries, 4831 sizeof(int), 0644, proc_dointvec_minmax, false); 4832 set_table_entry(&table[10], "flags", &sd->flags, 4833 sizeof(int), 0644, proc_dointvec_minmax, false); 4834 set_table_entry(&table[11], "name", sd->name, 4835 CORENAME_MAX_SIZE, 0444, proc_dostring, false); 4836 /* &table[12] is terminator */ 4837 4838 return table; 4839} 4840 4841static struct ctl_table *sd_alloc_ctl_cpu_table(int cpu) 4842{ 4843 struct ctl_table *entry, *table; 4844 struct sched_domain *sd; 4845 int domain_num = 0, i; 4846 char buf[32]; 4847 4848 for_each_domain(cpu, sd) 4849 domain_num++; 4850 entry = table = sd_alloc_ctl_entry(domain_num + 1); 4851 if (table == NULL) 4852 return NULL; 4853 4854 i = 0; 4855 for_each_domain(cpu, sd) { 4856 snprintf(buf, 32, "domain%d", i); 4857 entry->procname = kstrdup(buf, GFP_KERNEL); 4858 entry->mode = 0555; 4859 entry->child = sd_alloc_ctl_domain_table(sd); 4860 entry++; 4861 i++; 4862 } 4863 return table; 4864} 4865 4866static struct ctl_table_header *sd_sysctl_header; 4867static void register_sched_domain_sysctl(void) 4868{ 4869 int i, cpu_num = num_possible_cpus(); 4870 struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1); 4871 char buf[32]; 4872 4873 WARN_ON(sd_ctl_dir[0].child); 4874 sd_ctl_dir[0].child = entry; 4875 4876 if (entry == NULL) 4877 return; 4878 4879 for_each_possible_cpu(i) { 4880 snprintf(buf, 32, "cpu%d", i); 4881 entry->procname = kstrdup(buf, GFP_KERNEL); 4882 entry->mode = 0555; 4883 entry->child = sd_alloc_ctl_cpu_table(i); 4884 entry++; 4885 } 4886 4887 WARN_ON(sd_sysctl_header); 4888 sd_sysctl_header = register_sysctl_table(sd_ctl_root); 4889} 4890 4891/* may be called multiple times per register */ 4892static void unregister_sched_domain_sysctl(void) 4893{ 4894 if (sd_sysctl_header) 4895 unregister_sysctl_table(sd_sysctl_header); 4896 sd_sysctl_header = NULL; 4897 if (sd_ctl_dir[0].child) 4898 sd_free_ctl_entry(&sd_ctl_dir[0].child); 4899} 4900#else 4901static void register_sched_domain_sysctl(void) 4902{ 4903} 4904static void unregister_sched_domain_sysctl(void) 4905{ 4906} 4907#endif 4908 4909static void set_rq_online(struct rq *rq) 4910{ 4911 if (!rq->online) { 4912 const struct sched_class *class; 4913 4914 cpumask_set_cpu(rq->cpu, rq->rd->online); 4915 rq->online = 1; 4916 4917 for_each_class(class) { 4918 if (class->rq_online) 4919 class->rq_online(rq); 4920 } 4921 } 4922} 4923 4924static void set_rq_offline(struct rq *rq) 4925{ 4926 if (rq->online) { 4927 const struct sched_class *class; 4928 4929 for_each_class(class) { 4930 if (class->rq_offline) 4931 class->rq_offline(rq); 4932 } 4933 4934 cpumask_clear_cpu(rq->cpu, rq->rd->online); 4935 rq->online = 0; 4936 } 4937} 4938 4939/* 4940 * migration_call - callback that gets triggered when a CPU is added. 4941 * Here we can start up the necessary migration thread for the new CPU. 4942 */ 4943static int 4944migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) 4945{ 4946 int cpu = (long)hcpu; 4947 unsigned long flags; 4948 struct rq *rq = cpu_rq(cpu); 4949 4950 switch (action & ~CPU_TASKS_FROZEN) { 4951 4952 case CPU_UP_PREPARE: 4953 rq->calc_load_update = calc_load_update; 4954 break; 4955 4956 case CPU_ONLINE: 4957 /* Update our root-domain */ 4958 raw_spin_lock_irqsave(&rq->lock, flags); 4959 if (rq->rd) { 4960 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); 4961 4962 set_rq_online(rq); 4963 } 4964 raw_spin_unlock_irqrestore(&rq->lock, flags); 4965 break; 4966 4967#ifdef CONFIG_HOTPLUG_CPU 4968 case CPU_DYING: 4969 sched_ttwu_pending(); 4970 /* Update our root-domain */ 4971 raw_spin_lock_irqsave(&rq->lock, flags); 4972 if (rq->rd) { 4973 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); 4974 set_rq_offline(rq); 4975 } 4976 migrate_tasks(cpu); 4977 BUG_ON(rq->nr_running != 1); /* the migration thread */ 4978 raw_spin_unlock_irqrestore(&rq->lock, flags); 4979 break; 4980 4981 case CPU_DEAD: 4982 calc_load_migrate(rq); 4983 break; 4984#endif 4985 } 4986 4987 update_max_interval(); 4988 4989 return NOTIFY_OK; 4990} 4991 4992/* 4993 * Register at high priority so that task migration (migrate_all_tasks) 4994 * happens before everything else. This has to be lower priority than 4995 * the notifier in the perf_event subsystem, though. 4996 */ 4997static struct notifier_block migration_notifier = { 4998 .notifier_call = migration_call, 4999 .priority = CPU_PRI_MIGRATION, 5000}; 5001 5002static int sched_cpu_active(struct notifier_block *nfb, 5003 unsigned long action, void *hcpu) 5004{ 5005 switch (action & ~CPU_TASKS_FROZEN) { 5006 case CPU_STARTING: 5007 case CPU_DOWN_FAILED: 5008 set_cpu_active((long)hcpu, true); 5009 return NOTIFY_OK; 5010 default: 5011 return NOTIFY_DONE; 5012 } 5013} 5014 5015static int sched_cpu_inactive(struct notifier_block *nfb, 5016 unsigned long action, void *hcpu) 5017{ 5018 unsigned long flags; 5019 long cpu = (long)hcpu; 5020 5021 switch (action & ~CPU_TASKS_FROZEN) { 5022 case CPU_DOWN_PREPARE: 5023 set_cpu_active(cpu, false); 5024 5025 /* explicitly allow suspend */ 5026 if (!(action & CPU_TASKS_FROZEN)) { 5027 struct dl_bw *dl_b = dl_bw_of(cpu); 5028 bool overflow; 5029 int cpus; 5030 5031 raw_spin_lock_irqsave(&dl_b->lock, flags); 5032 cpus = dl_bw_cpus(cpu); 5033 overflow = __dl_overflow(dl_b, cpus, 0, 0); 5034 raw_spin_unlock_irqrestore(&dl_b->lock, flags); 5035 5036 if (overflow) 5037 return notifier_from_errno(-EBUSY); 5038 } 5039 return NOTIFY_OK; 5040 } 5041 5042 return NOTIFY_DONE; 5043} 5044 5045static int __init migration_init(void) 5046{ 5047 void *cpu = (void *)(long)smp_processor_id(); 5048 int err; 5049 5050 /* Initialize migration for the boot CPU */ 5051 err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); 5052 BUG_ON(err == NOTIFY_BAD); 5053 migration_call(&migration_notifier, CPU_ONLINE, cpu); 5054 register_cpu_notifier(&migration_notifier); 5055 5056 /* Register cpu active notifiers */ 5057 cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE); 5058 cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE); 5059 5060 return 0; 5061} 5062early_initcall(migration_init); 5063#endif 5064 5065#ifdef CONFIG_SMP 5066 5067static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */ 5068 5069#ifdef CONFIG_SCHED_DEBUG 5070 5071static __read_mostly int sched_debug_enabled; 5072 5073static int __init sched_debug_setup(char *str) 5074{ 5075 sched_debug_enabled = 1; 5076 5077 return 0; 5078} 5079early_param("sched_debug", sched_debug_setup); 5080 5081static inline bool sched_debug(void) 5082{ 5083 return sched_debug_enabled; 5084} 5085 5086static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, 5087 struct cpumask *groupmask) 5088{ 5089 struct sched_group *group = sd->groups; 5090 char str[256]; 5091 5092 cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd)); 5093 cpumask_clear(groupmask); 5094 5095 printk(KERN_DEBUG "%*s domain %d: ", level, "", level); 5096 5097 if (!(sd->flags & SD_LOAD_BALANCE)) { 5098 printk("does not load-balance\n"); 5099 if (sd->parent) 5100 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain" 5101 " has parent"); 5102 return -1; 5103 } 5104 5105 printk(KERN_CONT "span %s level %s\n", str, sd->name); 5106 5107 if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) { 5108 printk(KERN_ERR "ERROR: domain->span does not contain " 5109 "CPU%d\n", cpu); 5110 } 5111 if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) { 5112 printk(KERN_ERR "ERROR: domain->groups does not contain" 5113 " CPU%d\n", cpu); 5114 } 5115 5116 printk(KERN_DEBUG "%*s groups:", level + 1, ""); 5117 do { 5118 if (!group) { 5119 printk("\n"); 5120 printk(KERN_ERR "ERROR: group is NULL\n"); 5121 break; 5122 } 5123 5124 /* 5125 * Even though we initialize ->power to something semi-sane, 5126 * we leave power_orig unset. This allows us to detect if 5127 * domain iteration is still funny without causing /0 traps. 5128 */ 5129 if (!group->sgp->power_orig) { 5130 printk(KERN_CONT "\n"); 5131 printk(KERN_ERR "ERROR: domain->cpu_power not " 5132 "set\n"); 5133 break; 5134 } 5135 5136 if (!cpumask_weight(sched_group_cpus(group))) { 5137 printk(KERN_CONT "\n"); 5138 printk(KERN_ERR "ERROR: empty group\n"); 5139 break; 5140 } 5141 5142 if (!(sd->flags & SD_OVERLAP) && 5143 cpumask_intersects(groupmask, sched_group_cpus(group))) { 5144 printk(KERN_CONT "\n"); 5145 printk(KERN_ERR "ERROR: repeated CPUs\n"); 5146 break; 5147 } 5148 5149 cpumask_or(groupmask, groupmask, sched_group_cpus(group)); 5150 5151 cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group)); 5152 5153 printk(KERN_CONT " %s", str); 5154 if (group->sgp->power != SCHED_POWER_SCALE) { 5155 printk(KERN_CONT " (cpu_power = %d)", 5156 group->sgp->power); 5157 } 5158 5159 group = group->next; 5160 } while (group != sd->groups); 5161 printk(KERN_CONT "\n"); 5162 5163 if (!cpumask_equal(sched_domain_span(sd), groupmask)) 5164 printk(KERN_ERR "ERROR: groups don't span domain->span\n"); 5165 5166 if (sd->parent && 5167 !cpumask_subset(groupmask, sched_domain_span(sd->parent))) 5168 printk(KERN_ERR "ERROR: parent span is not a superset " 5169 "of domain->span\n"); 5170 return 0; 5171} 5172 5173static void sched_domain_debug(struct sched_domain *sd, int cpu) 5174{ 5175 int level = 0; 5176 5177 if (!sched_debug_enabled) 5178 return; 5179 5180 if (!sd) { 5181 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); 5182 return; 5183 } 5184 5185 printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); 5186 5187 for (;;) { 5188 if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask)) 5189 break; 5190 level++; 5191 sd = sd->parent; 5192 if (!sd) 5193 break; 5194 } 5195} 5196#else /* !CONFIG_SCHED_DEBUG */ 5197# define sched_domain_debug(sd, cpu) do { } while (0) 5198static inline bool sched_debug(void) 5199{ 5200 return false; 5201} 5202#endif /* CONFIG_SCHED_DEBUG */ 5203 5204static int sd_degenerate(struct sched_domain *sd) 5205{ 5206 if (cpumask_weight(sched_domain_span(sd)) == 1) 5207 return 1; 5208 5209 /* Following flags need at least 2 groups */ 5210 if (sd->flags & (SD_LOAD_BALANCE | 5211 SD_BALANCE_NEWIDLE | 5212 SD_BALANCE_FORK | 5213 SD_BALANCE_EXEC | 5214 SD_SHARE_CPUPOWER | 5215 SD_SHARE_PKG_RESOURCES)) { 5216 if (sd->groups != sd->groups->next) 5217 return 0; 5218 } 5219 5220 /* Following flags don't use groups */ 5221 if (sd->flags & (SD_WAKE_AFFINE)) 5222 return 0; 5223 5224 return 1; 5225} 5226 5227static int 5228sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) 5229{ 5230 unsigned long cflags = sd->flags, pflags = parent->flags; 5231 5232 if (sd_degenerate(parent)) 5233 return 1; 5234 5235 if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent))) 5236 return 0; 5237 5238 /* Flags needing groups don't count if only 1 group in parent */ 5239 if (parent->groups == parent->groups->next) { 5240 pflags &= ~(SD_LOAD_BALANCE | 5241 SD_BALANCE_NEWIDLE | 5242 SD_BALANCE_FORK | 5243 SD_BALANCE_EXEC | 5244 SD_SHARE_CPUPOWER | 5245 SD_SHARE_PKG_RESOURCES | 5246 SD_PREFER_SIBLING); 5247 if (nr_node_ids == 1) 5248 pflags &= ~SD_SERIALIZE; 5249 } 5250 if (~cflags & pflags) 5251 return 0; 5252 5253 return 1; 5254} 5255 5256static void free_rootdomain(struct rcu_head *rcu) 5257{ 5258 struct root_domain *rd = container_of(rcu, struct root_domain, rcu); 5259 5260 cpupri_cleanup(&rd->cpupri); 5261 cpudl_cleanup(&rd->cpudl); 5262 free_cpumask_var(rd->dlo_mask); 5263 free_cpumask_var(rd->rto_mask); 5264 free_cpumask_var(rd->online); 5265 free_cpumask_var(rd->span); 5266 kfree(rd); 5267} 5268 5269static void rq_attach_root(struct rq *rq, struct root_domain *rd) 5270{ 5271 struct root_domain *old_rd = NULL; 5272 unsigned long flags; 5273 5274 raw_spin_lock_irqsave(&rq->lock, flags); 5275 5276 if (rq->rd) { 5277 old_rd = rq->rd; 5278 5279 if (cpumask_test_cpu(rq->cpu, old_rd->online)) 5280 set_rq_offline(rq); 5281 5282 cpumask_clear_cpu(rq->cpu, old_rd->span); 5283 5284 /* 5285 * If we dont want to free the old_rd yet then 5286 * set old_rd to NULL to skip the freeing later 5287 * in this function: 5288 */ 5289 if (!atomic_dec_and_test(&old_rd->refcount)) 5290 old_rd = NULL; 5291 } 5292 5293 atomic_inc(&rd->refcount); 5294 rq->rd = rd; 5295 5296 cpumask_set_cpu(rq->cpu, rd->span); 5297 if (cpumask_test_cpu(rq->cpu, cpu_active_mask)) 5298 set_rq_online(rq); 5299 5300 raw_spin_unlock_irqrestore(&rq->lock, flags); 5301 5302 if (old_rd) 5303 call_rcu_sched(&old_rd->rcu, free_rootdomain); 5304} 5305 5306static int init_rootdomain(struct root_domain *rd) 5307{ 5308 memset(rd, 0, sizeof(*rd)); 5309 5310 if (!alloc_cpumask_var(&rd->span, GFP_KERNEL)) 5311 goto out; 5312 if (!alloc_cpumask_var(&rd->online, GFP_KERNEL)) 5313 goto free_span; 5314 if (!alloc_cpumask_var(&rd->dlo_mask, GFP_KERNEL)) 5315 goto free_online; 5316 if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL)) 5317 goto free_dlo_mask; 5318 5319 init_dl_bw(&rd->dl_bw); 5320 if (cpudl_init(&rd->cpudl) != 0) 5321 goto free_dlo_mask; 5322 5323 if (cpupri_init(&rd->cpupri) != 0) 5324 goto free_rto_mask; 5325 return 0; 5326 5327free_rto_mask: 5328 free_cpumask_var(rd->rto_mask); 5329free_dlo_mask: 5330 free_cpumask_var(rd->dlo_mask); 5331free_online: 5332 free_cpumask_var(rd->online); 5333free_span: 5334 free_cpumask_var(rd->span); 5335out: 5336 return -ENOMEM; 5337} 5338 5339/* 5340 * By default the system creates a single root-domain with all cpus as 5341 * members (mimicking the global state we have today). 5342 */ 5343struct root_domain def_root_domain; 5344 5345static void init_defrootdomain(void) 5346{ 5347 init_rootdomain(&def_root_domain); 5348 5349 atomic_set(&def_root_domain.refcount, 1); 5350} 5351 5352static struct root_domain *alloc_rootdomain(void) 5353{ 5354 struct root_domain *rd; 5355 5356 rd = kmalloc(sizeof(*rd), GFP_KERNEL); 5357 if (!rd) 5358 return NULL; 5359 5360 if (init_rootdomain(rd) != 0) { 5361 kfree(rd); 5362 return NULL; 5363 } 5364 5365 return rd; 5366} 5367 5368static void free_sched_groups(struct sched_group *sg, int free_sgp) 5369{ 5370 struct sched_group *tmp, *first; 5371 5372 if (!sg) 5373 return; 5374 5375 first = sg; 5376 do { 5377 tmp = sg->next; 5378 5379 if (free_sgp && atomic_dec_and_test(&sg->sgp->ref)) 5380 kfree(sg->sgp); 5381 5382 kfree(sg); 5383 sg = tmp; 5384 } while (sg != first); 5385} 5386 5387static void free_sched_domain(struct rcu_head *rcu) 5388{ 5389 struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu); 5390 5391 /* 5392 * If its an overlapping domain it has private groups, iterate and 5393 * nuke them all. 5394 */ 5395 if (sd->flags & SD_OVERLAP) { 5396 free_sched_groups(sd->groups, 1); 5397 } else if (atomic_dec_and_test(&sd->groups->ref)) { 5398 kfree(sd->groups->sgp); 5399 kfree(sd->groups); 5400 } 5401 kfree(sd); 5402} 5403 5404static void destroy_sched_domain(struct sched_domain *sd, int cpu) 5405{ 5406 call_rcu(&sd->rcu, free_sched_domain); 5407} 5408 5409static void destroy_sched_domains(struct sched_domain *sd, int cpu) 5410{ 5411 for (; sd; sd = sd->parent) 5412 destroy_sched_domain(sd, cpu); 5413} 5414 5415/* 5416 * Keep a special pointer to the highest sched_domain that has 5417 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this 5418 * allows us to avoid some pointer chasing select_idle_sibling(). 5419 * 5420 * Also keep a unique ID per domain (we use the first cpu number in 5421 * the cpumask of the domain), this allows us to quickly tell if 5422 * two cpus are in the same cache domain, see cpus_share_cache(). 5423 */ 5424DEFINE_PER_CPU(struct sched_domain *, sd_llc); 5425DEFINE_PER_CPU(int, sd_llc_size); 5426DEFINE_PER_CPU(int, sd_llc_id); 5427DEFINE_PER_CPU(struct sched_domain *, sd_numa); 5428DEFINE_PER_CPU(struct sched_domain *, sd_busy); 5429DEFINE_PER_CPU(struct sched_domain *, sd_asym); 5430 5431static void update_top_cache_domain(int cpu) 5432{ 5433 struct sched_domain *sd; 5434 struct sched_domain *busy_sd = NULL; 5435 int id = cpu; 5436 int size = 1; 5437 5438 sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES); 5439 if (sd) { 5440 id = cpumask_first(sched_domain_span(sd)); 5441 size = cpumask_weight(sched_domain_span(sd)); 5442 busy_sd = sd->parent; /* sd_busy */ 5443 } 5444 rcu_assign_pointer(per_cpu(sd_busy, cpu), busy_sd); 5445 5446 rcu_assign_pointer(per_cpu(sd_llc, cpu), sd); 5447 per_cpu(sd_llc_size, cpu) = size; 5448 per_cpu(sd_llc_id, cpu) = id; 5449 5450 sd = lowest_flag_domain(cpu, SD_NUMA); 5451 rcu_assign_pointer(per_cpu(sd_numa, cpu), sd); 5452 5453 sd = highest_flag_domain(cpu, SD_ASYM_PACKING); 5454 rcu_assign_pointer(per_cpu(sd_asym, cpu), sd); 5455} 5456 5457/* 5458 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must 5459 * hold the hotplug lock. 5460 */ 5461static void 5462cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) 5463{ 5464 struct rq *rq = cpu_rq(cpu); 5465 struct sched_domain *tmp; 5466 5467 /* Remove the sched domains which do not contribute to scheduling. */ 5468 for (tmp = sd; tmp; ) { 5469 struct sched_domain *parent = tmp->parent; 5470 if (!parent) 5471 break; 5472 5473 if (sd_parent_degenerate(tmp, parent)) { 5474 tmp->parent = parent->parent; 5475 if (parent->parent) 5476 parent->parent->child = tmp; 5477 /* 5478 * Transfer SD_PREFER_SIBLING down in case of a 5479 * degenerate parent; the spans match for this 5480 * so the property transfers. 5481 */ 5482 if (parent->flags & SD_PREFER_SIBLING) 5483 tmp->flags |= SD_PREFER_SIBLING; 5484 destroy_sched_domain(parent, cpu); 5485 } else 5486 tmp = tmp->parent; 5487 } 5488 5489 if (sd && sd_degenerate(sd)) { 5490 tmp = sd; 5491 sd = sd->parent; 5492 destroy_sched_domain(tmp, cpu); 5493 if (sd) 5494 sd->child = NULL; 5495 } 5496 5497 sched_domain_debug(sd, cpu); 5498 5499 rq_attach_root(rq, rd); 5500 tmp = rq->sd; 5501 rcu_assign_pointer(rq->sd, sd); 5502 destroy_sched_domains(tmp, cpu); 5503 5504 update_top_cache_domain(cpu); 5505} 5506 5507/* cpus with isolated domains */ 5508static cpumask_var_t cpu_isolated_map; 5509 5510/* Setup the mask of cpus configured for isolated domains */ 5511static int __init isolated_cpu_setup(char *str) 5512{ 5513 alloc_bootmem_cpumask_var(&cpu_isolated_map); 5514 cpulist_parse(str, cpu_isolated_map); 5515 return 1; 5516} 5517 5518__setup("isolcpus=", isolated_cpu_setup); 5519 5520static const struct cpumask *cpu_cpu_mask(int cpu) 5521{ 5522 return cpumask_of_node(cpu_to_node(cpu)); 5523} 5524 5525struct sd_data { 5526 struct sched_domain **__percpu sd; 5527 struct sched_group **__percpu sg; 5528 struct sched_group_power **__percpu sgp; 5529}; 5530 5531struct s_data { 5532 struct sched_domain ** __percpu sd; 5533 struct root_domain *rd; 5534}; 5535 5536enum s_alloc { 5537 sa_rootdomain, 5538 sa_sd, 5539 sa_sd_storage, 5540 sa_none, 5541}; 5542 5543struct sched_domain_topology_level; 5544 5545typedef struct sched_domain *(*sched_domain_init_f)(struct sched_domain_topology_level *tl, int cpu); 5546typedef const struct cpumask *(*sched_domain_mask_f)(int cpu); 5547 5548#define SDTL_OVERLAP 0x01 5549 5550struct sched_domain_topology_level { 5551 sched_domain_init_f init; 5552 sched_domain_mask_f mask; 5553 int flags; 5554 int numa_level; 5555 struct sd_data data; 5556}; 5557 5558/* 5559 * Build an iteration mask that can exclude certain CPUs from the upwards 5560 * domain traversal. 5561 * 5562 * Asymmetric node setups can result in situations where the domain tree is of 5563 * unequal depth, make sure to skip domains that already cover the entire 5564 * range. 5565 * 5566 * In that case build_sched_domains() will have terminated the iteration early 5567 * and our sibling sd spans will be empty. Domains should always include the 5568 * cpu they're built on, so check that. 5569 * 5570 */ 5571static void build_group_mask(struct sched_domain *sd, struct sched_group *sg) 5572{ 5573 const struct cpumask *span = sched_domain_span(sd); 5574 struct sd_data *sdd = sd->private; 5575 struct sched_domain *sibling; 5576 int i; 5577 5578 for_each_cpu(i, span) { 5579 sibling = *per_cpu_ptr(sdd->sd, i); 5580 if (!cpumask_test_cpu(i, sched_domain_span(sibling))) 5581 continue; 5582 5583 cpumask_set_cpu(i, sched_group_mask(sg)); 5584 } 5585} 5586 5587/* 5588 * Return the canonical balance cpu for this group, this is the first cpu 5589 * of this group that's also in the iteration mask. 5590 */ 5591int group_balance_cpu(struct sched_group *sg) 5592{ 5593 return cpumask_first_and(sched_group_cpus(sg), sched_group_mask(sg)); 5594} 5595 5596static int 5597build_overlap_sched_groups(struct sched_domain *sd, int cpu) 5598{ 5599 struct sched_group *first = NULL, *last = NULL, *groups = NULL, *sg; 5600 const struct cpumask *span = sched_domain_span(sd); 5601 struct cpumask *covered = sched_domains_tmpmask; 5602 struct sd_data *sdd = sd->private; 5603 struct sched_domain *child; 5604 int i; 5605 5606 cpumask_clear(covered); 5607 5608 for_each_cpu(i, span) { 5609 struct cpumask *sg_span; 5610 5611 if (cpumask_test_cpu(i, covered)) 5612 continue; 5613 5614 child = *per_cpu_ptr(sdd->sd, i); 5615 5616 /* See the comment near build_group_mask(). */ 5617 if (!cpumask_test_cpu(i, sched_domain_span(child))) 5618 continue; 5619 5620 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), 5621 GFP_KERNEL, cpu_to_node(cpu)); 5622 5623 if (!sg) 5624 goto fail; 5625 5626 sg_span = sched_group_cpus(sg); 5627 if (child->child) { 5628 child = child->child; 5629 cpumask_copy(sg_span, sched_domain_span(child)); 5630 } else 5631 cpumask_set_cpu(i, sg_span); 5632 5633 cpumask_or(covered, covered, sg_span); 5634 5635 sg->sgp = *per_cpu_ptr(sdd->sgp, i); 5636 if (atomic_inc_return(&sg->sgp->ref) == 1) 5637 build_group_mask(sd, sg); 5638 5639 /* 5640 * Initialize sgp->power such that even if we mess up the 5641 * domains and no possible iteration will get us here, we won't 5642 * die on a /0 trap. 5643 */ 5644 sg->sgp->power = SCHED_POWER_SCALE * cpumask_weight(sg_span); 5645 sg->sgp->power_orig = sg->sgp->power; 5646 5647 /* 5648 * Make sure the first group of this domain contains the 5649 * canonical balance cpu. Otherwise the sched_domain iteration 5650 * breaks. See update_sg_lb_stats(). 5651 */ 5652 if ((!groups && cpumask_test_cpu(cpu, sg_span)) || 5653 group_balance_cpu(sg) == cpu) 5654 groups = sg; 5655 5656 if (!first) 5657 first = sg; 5658 if (last) 5659 last->next = sg; 5660 last = sg; 5661 last->next = first; 5662 } 5663 sd->groups = groups; 5664 5665 return 0; 5666 5667fail: 5668 free_sched_groups(first, 0); 5669 5670 return -ENOMEM; 5671} 5672 5673static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg) 5674{ 5675 struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu); 5676 struct sched_domain *child = sd->child; 5677 5678 if (child) 5679 cpu = cpumask_first(sched_domain_span(child)); 5680 5681 if (sg) { 5682 *sg = *per_cpu_ptr(sdd->sg, cpu); 5683 (*sg)->sgp = *per_cpu_ptr(sdd->sgp, cpu); 5684 atomic_set(&(*sg)->sgp->ref, 1); /* for claim_allocations */ 5685 } 5686 5687 return cpu; 5688} 5689 5690/* 5691 * build_sched_groups will build a circular linked list of the groups 5692 * covered by the given span, and will set each group's ->cpumask correctly, 5693 * and ->cpu_power to 0. 5694 * 5695 * Assumes the sched_domain tree is fully constructed 5696 */ 5697static int 5698build_sched_groups(struct sched_domain *sd, int cpu) 5699{ 5700 struct sched_group *first = NULL, *last = NULL; 5701 struct sd_data *sdd = sd->private; 5702 const struct cpumask *span = sched_domain_span(sd); 5703 struct cpumask *covered; 5704 int i; 5705 5706 get_group(cpu, sdd, &sd->groups); 5707 atomic_inc(&sd->groups->ref); 5708 5709 if (cpu != cpumask_first(span)) 5710 return 0; 5711 5712 lockdep_assert_held(&sched_domains_mutex); 5713 covered = sched_domains_tmpmask; 5714 5715 cpumask_clear(covered); 5716 5717 for_each_cpu(i, span) { 5718 struct sched_group *sg; 5719 int group, j; 5720 5721 if (cpumask_test_cpu(i, covered)) 5722 continue; 5723 5724 group = get_group(i, sdd, &sg); 5725 cpumask_clear(sched_group_cpus(sg)); 5726 sg->sgp->power = 0; 5727 cpumask_setall(sched_group_mask(sg)); 5728 5729 for_each_cpu(j, span) { 5730 if (get_group(j, sdd, NULL) != group) 5731 continue; 5732 5733 cpumask_set_cpu(j, covered); 5734 cpumask_set_cpu(j, sched_group_cpus(sg)); 5735 } 5736 5737 if (!first) 5738 first = sg; 5739 if (last) 5740 last->next = sg; 5741 last = sg; 5742 } 5743 last->next = first; 5744 5745 return 0; 5746} 5747 5748/* 5749 * Initialize sched groups cpu_power. 5750 * 5751 * cpu_power indicates the capacity of sched group, which is used while 5752 * distributing the load between different sched groups in a sched domain. 5753 * Typically cpu_power for all the groups in a sched domain will be same unless 5754 * there are asymmetries in the topology. If there are asymmetries, group 5755 * having more cpu_power will pickup more load compared to the group having 5756 * less cpu_power. 5757 */ 5758static void init_sched_groups_power(int cpu, struct sched_domain *sd) 5759{ 5760 struct sched_group *sg = sd->groups; 5761 5762 WARN_ON(!sg); 5763 5764 do { 5765 sg->group_weight = cpumask_weight(sched_group_cpus(sg)); 5766 sg = sg->next; 5767 } while (sg != sd->groups); 5768 5769 if (cpu != group_balance_cpu(sg)) 5770 return; 5771 5772 update_group_power(sd, cpu); 5773 atomic_set(&sg->sgp->nr_busy_cpus, sg->group_weight); 5774} 5775 5776int __weak arch_sd_sibling_asym_packing(void) 5777{ 5778 return 0*SD_ASYM_PACKING; 5779} 5780 5781/* 5782 * Initializers for schedule domains 5783 * Non-inlined to reduce accumulated stack pressure in build_sched_domains() 5784 */ 5785 5786#ifdef CONFIG_SCHED_DEBUG 5787# define SD_INIT_NAME(sd, type) sd->name = #type 5788#else 5789# define SD_INIT_NAME(sd, type) do { } while (0) 5790#endif 5791 5792#define SD_INIT_FUNC(type) \ 5793static noinline struct sched_domain * \ 5794sd_init_##type(struct sched_domain_topology_level *tl, int cpu) \ 5795{ \ 5796 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); \ 5797 *sd = SD_##type##_INIT; \ 5798 SD_INIT_NAME(sd, type); \ 5799 sd->private = &tl->data; \ 5800 return sd; \ 5801} 5802 5803SD_INIT_FUNC(CPU) 5804#ifdef CONFIG_SCHED_SMT 5805 SD_INIT_FUNC(SIBLING) 5806#endif 5807#ifdef CONFIG_SCHED_MC 5808 SD_INIT_FUNC(MC) 5809#endif 5810#ifdef CONFIG_SCHED_BOOK 5811 SD_INIT_FUNC(BOOK) 5812#endif 5813 5814static int default_relax_domain_level = -1; 5815int sched_domain_level_max; 5816 5817static int __init setup_relax_domain_level(char *str) 5818{ 5819 if (kstrtoint(str, 0, &default_relax_domain_level)) 5820 pr_warn("Unable to set relax_domain_level\n"); 5821 5822 return 1; 5823} 5824__setup("relax_domain_level=", setup_relax_domain_level); 5825 5826static void set_domain_attribute(struct sched_domain *sd, 5827 struct sched_domain_attr *attr) 5828{ 5829 int request; 5830 5831 if (!attr || attr->relax_domain_level < 0) { 5832 if (default_relax_domain_level < 0) 5833 return; 5834 else 5835 request = default_relax_domain_level; 5836 } else 5837 request = attr->relax_domain_level; 5838 if (request < sd->level) { 5839 /* turn off idle balance on this domain */ 5840 sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); 5841 } else { 5842 /* turn on idle balance on this domain */ 5843 sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); 5844 } 5845} 5846 5847static void __sdt_free(const struct cpumask *cpu_map); 5848static int __sdt_alloc(const struct cpumask *cpu_map); 5849 5850static void __free_domain_allocs(struct s_data *d, enum s_alloc what, 5851 const struct cpumask *cpu_map) 5852{ 5853 switch (what) { 5854 case sa_rootdomain: 5855 if (!atomic_read(&d->rd->refcount)) 5856 free_rootdomain(&d->rd->rcu); /* fall through */ 5857 case sa_sd: 5858 free_percpu(d->sd); /* fall through */ 5859 case sa_sd_storage: 5860 __sdt_free(cpu_map); /* fall through */ 5861 case sa_none: 5862 break; 5863 } 5864} 5865 5866static enum s_alloc __visit_domain_allocation_hell(struct s_data *d, 5867 const struct cpumask *cpu_map) 5868{ 5869 memset(d, 0, sizeof(*d)); 5870 5871 if (__sdt_alloc(cpu_map)) 5872 return sa_sd_storage; 5873 d->sd = alloc_percpu(struct sched_domain *); 5874 if (!d->sd) 5875 return sa_sd_storage; 5876 d->rd = alloc_rootdomain(); 5877 if (!d->rd) 5878 return sa_sd; 5879 return sa_rootdomain; 5880} 5881 5882/* 5883 * NULL the sd_data elements we've used to build the sched_domain and 5884 * sched_group structure so that the subsequent __free_domain_allocs() 5885 * will not free the data we're using. 5886 */ 5887static void claim_allocations(int cpu, struct sched_domain *sd) 5888{ 5889 struct sd_data *sdd = sd->private; 5890 5891 WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd); 5892 *per_cpu_ptr(sdd->sd, cpu) = NULL; 5893 5894 if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref)) 5895 *per_cpu_ptr(sdd->sg, cpu) = NULL; 5896 5897 if (atomic_read(&(*per_cpu_ptr(sdd->sgp, cpu))->ref)) 5898 *per_cpu_ptr(sdd->sgp, cpu) = NULL; 5899} 5900 5901#ifdef CONFIG_SCHED_SMT 5902static const struct cpumask *cpu_smt_mask(int cpu) 5903{ 5904 return topology_thread_cpumask(cpu); 5905} 5906#endif 5907 5908/* 5909 * Topology list, bottom-up. 5910 */ 5911static struct sched_domain_topology_level default_topology[] = { 5912#ifdef CONFIG_SCHED_SMT 5913 { sd_init_SIBLING, cpu_smt_mask, }, 5914#endif 5915#ifdef CONFIG_SCHED_MC 5916 { sd_init_MC, cpu_coregroup_mask, }, 5917#endif 5918#ifdef CONFIG_SCHED_BOOK 5919 { sd_init_BOOK, cpu_book_mask, }, 5920#endif 5921 { sd_init_CPU, cpu_cpu_mask, }, 5922 { NULL, }, 5923}; 5924 5925static struct sched_domain_topology_level *sched_domain_topology = default_topology; 5926 5927#define for_each_sd_topology(tl) \ 5928 for (tl = sched_domain_topology; tl->init; tl++) 5929 5930#ifdef CONFIG_NUMA 5931 5932static int sched_domains_numa_levels; 5933static int *sched_domains_numa_distance; 5934static struct cpumask ***sched_domains_numa_masks; 5935static int sched_domains_curr_level; 5936 5937static inline int sd_local_flags(int level) 5938{ 5939 if (sched_domains_numa_distance[level] > RECLAIM_DISTANCE) 5940 return 0; 5941 5942 return SD_BALANCE_EXEC | SD_BALANCE_FORK | SD_WAKE_AFFINE; 5943} 5944 5945static struct sched_domain * 5946sd_numa_init(struct sched_domain_topology_level *tl, int cpu) 5947{ 5948 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); 5949 int level = tl->numa_level; 5950 int sd_weight = cpumask_weight( 5951 sched_domains_numa_masks[level][cpu_to_node(cpu)]); 5952 5953 *sd = (struct sched_domain){ 5954 .min_interval = sd_weight, 5955 .max_interval = 2*sd_weight, 5956 .busy_factor = 32, 5957 .imbalance_pct = 125, 5958 .cache_nice_tries = 2, 5959 .busy_idx = 3, 5960 .idle_idx = 2, 5961 .newidle_idx = 0, 5962 .wake_idx = 0, 5963 .forkexec_idx = 0, 5964 5965 .flags = 1*SD_LOAD_BALANCE 5966 | 1*SD_BALANCE_NEWIDLE 5967 | 0*SD_BALANCE_EXEC 5968 | 0*SD_BALANCE_FORK 5969 | 0*SD_BALANCE_WAKE 5970 | 0*SD_WAKE_AFFINE 5971 | 0*SD_SHARE_CPUPOWER 5972 | 0*SD_SHARE_PKG_RESOURCES 5973 | 1*SD_SERIALIZE 5974 | 0*SD_PREFER_SIBLING 5975 | 1*SD_NUMA 5976 | sd_local_flags(level) 5977 , 5978 .last_balance = jiffies, 5979 .balance_interval = sd_weight, 5980 }; 5981 SD_INIT_NAME(sd, NUMA); 5982 sd->private = &tl->data; 5983 5984 /* 5985 * Ugly hack to pass state to sd_numa_mask()... 5986 */ 5987 sched_domains_curr_level = tl->numa_level; 5988 5989 return sd; 5990} 5991 5992static const struct cpumask *sd_numa_mask(int cpu) 5993{ 5994 return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)]; 5995} 5996 5997static void sched_numa_warn(const char *str) 5998{ 5999 static int done = false; 6000 int i,j; 6001 6002 if (done) 6003 return; 6004 6005 done = true; 6006 6007 printk(KERN_WARNING "ERROR: %s\n\n", str); 6008 6009 for (i = 0; i < nr_node_ids; i++) { 6010 printk(KERN_WARNING " "); 6011 for (j = 0; j < nr_node_ids; j++) 6012 printk(KERN_CONT "%02d ", node_distance(i,j)); 6013 printk(KERN_CONT "\n"); 6014 } 6015 printk(KERN_WARNING "\n"); 6016} 6017 6018static bool find_numa_distance(int distance) 6019{ 6020 int i; 6021 6022 if (distance == node_distance(0, 0)) 6023 return true; 6024 6025 for (i = 0; i < sched_domains_numa_levels; i++) { 6026 if (sched_domains_numa_distance[i] == distance) 6027 return true; 6028 } 6029 6030 return false; 6031} 6032 6033static void sched_init_numa(void) 6034{ 6035 int next_distance, curr_distance = node_distance(0, 0); 6036 struct sched_domain_topology_level *tl; 6037 int level = 0; 6038 int i, j, k; 6039 6040 sched_domains_numa_distance = kzalloc(sizeof(int) * nr_node_ids, GFP_KERNEL); 6041 if (!sched_domains_numa_distance) 6042 return; 6043 6044 /* 6045 * O(nr_nodes^2) deduplicating selection sort -- in order to find the 6046 * unique distances in the node_distance() table. 6047 * 6048 * Assumes node_distance(0,j) includes all distances in 6049 * node_distance(i,j) in order to avoid cubic time. 6050 */ 6051 next_distance = curr_distance; 6052 for (i = 0; i < nr_node_ids; i++) { 6053 for (j = 0; j < nr_node_ids; j++) { 6054 for (k = 0; k < nr_node_ids; k++) { 6055 int distance = node_distance(i, k); 6056 6057 if (distance > curr_distance && 6058 (distance < next_distance || 6059 next_distance == curr_distance)) 6060 next_distance = distance; 6061 6062 /* 6063 * While not a strong assumption it would be nice to know 6064 * about cases where if node A is connected to B, B is not 6065 * equally connected to A. 6066 */ 6067 if (sched_debug() && node_distance(k, i) != distance) 6068 sched_numa_warn("Node-distance not symmetric"); 6069 6070 if (sched_debug() && i && !find_numa_distance(distance)) 6071 sched_numa_warn("Node-0 not representative"); 6072 } 6073 if (next_distance != curr_distance) { 6074 sched_domains_numa_distance[level++] = next_distance; 6075 sched_domains_numa_levels = level; 6076 curr_distance = next_distance; 6077 } else break; 6078 } 6079 6080 /* 6081 * In case of sched_debug() we verify the above assumption. 6082 */ 6083 if (!sched_debug()) 6084 break; 6085 } 6086 /* 6087 * 'level' contains the number of unique distances, excluding the 6088 * identity distance node_distance(i,i). 6089 * 6090 * The sched_domains_numa_distance[] array includes the actual distance 6091 * numbers. 6092 */ 6093 6094 /* 6095 * Here, we should temporarily reset sched_domains_numa_levels to 0. 6096 * If it fails to allocate memory for array sched_domains_numa_masks[][], 6097 * the array will contain less then 'level' members. This could be 6098 * dangerous when we use it to iterate array sched_domains_numa_masks[][] 6099 * in other functions. 6100 * 6101 * We reset it to 'level' at the end of this function. 6102 */ 6103 sched_domains_numa_levels = 0; 6104 6105 sched_domains_numa_masks = kzalloc(sizeof(void *) * level, GFP_KERNEL); 6106 if (!sched_domains_numa_masks) 6107 return; 6108 6109 /* 6110 * Now for each level, construct a mask per node which contains all 6111 * cpus of nodes that are that many hops away from us. 6112 */ 6113 for (i = 0; i < level; i++) { 6114 sched_domains_numa_masks[i] = 6115 kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL); 6116 if (!sched_domains_numa_masks[i]) 6117 return; 6118 6119 for (j = 0; j < nr_node_ids; j++) { 6120 struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL); 6121 if (!mask) 6122 return; 6123 6124 sched_domains_numa_masks[i][j] = mask; 6125 6126 for (k = 0; k < nr_node_ids; k++) { 6127 if (node_distance(j, k) > sched_domains_numa_distance[i]) 6128 continue; 6129 6130 cpumask_or(mask, mask, cpumask_of_node(k)); 6131 } 6132 } 6133 } 6134 6135 tl = kzalloc((ARRAY_SIZE(default_topology) + level) * 6136 sizeof(struct sched_domain_topology_level), GFP_KERNEL); 6137 if (!tl) 6138 return; 6139 6140 /* 6141 * Copy the default topology bits.. 6142 */ 6143 for (i = 0; default_topology[i].init; i++) 6144 tl[i] = default_topology[i]; 6145 6146 /* 6147 * .. and append 'j' levels of NUMA goodness. 6148 */ 6149 for (j = 0; j < level; i++, j++) { 6150 tl[i] = (struct sched_domain_topology_level){ 6151 .init = sd_numa_init, 6152 .mask = sd_numa_mask, 6153 .flags = SDTL_OVERLAP, 6154 .numa_level = j, 6155 }; 6156 } 6157 6158 sched_domain_topology = tl; 6159 6160 sched_domains_numa_levels = level; 6161} 6162 6163static void sched_domains_numa_masks_set(int cpu) 6164{ 6165 int i, j; 6166 int node = cpu_to_node(cpu); 6167 6168 for (i = 0; i < sched_domains_numa_levels; i++) { 6169 for (j = 0; j < nr_node_ids; j++) { 6170 if (node_distance(j, node) <= sched_domains_numa_distance[i]) 6171 cpumask_set_cpu(cpu, sched_domains_numa_masks[i][j]); 6172 } 6173 } 6174} 6175 6176static void sched_domains_numa_masks_clear(int cpu) 6177{ 6178 int i, j; 6179 for (i = 0; i < sched_domains_numa_levels; i++) { 6180 for (j = 0; j < nr_node_ids; j++) 6181 cpumask_clear_cpu(cpu, sched_domains_numa_masks[i][j]); 6182 } 6183} 6184 6185/* 6186 * Update sched_domains_numa_masks[level][node] array when new cpus 6187 * are onlined. 6188 */ 6189static int sched_domains_numa_masks_update(struct notifier_block *nfb, 6190 unsigned long action, 6191 void *hcpu) 6192{ 6193 int cpu = (long)hcpu; 6194 6195 switch (action & ~CPU_TASKS_FROZEN) { 6196 case CPU_ONLINE: 6197 sched_domains_numa_masks_set(cpu); 6198 break; 6199 6200 case CPU_DEAD: 6201 sched_domains_numa_masks_clear(cpu); 6202 break; 6203 6204 default: 6205 return NOTIFY_DONE; 6206 } 6207 6208 return NOTIFY_OK; 6209} 6210#else 6211static inline void sched_init_numa(void) 6212{ 6213} 6214 6215static int sched_domains_numa_masks_update(struct notifier_block *nfb, 6216 unsigned long action, 6217 void *hcpu) 6218{ 6219 return 0; 6220} 6221#endif /* CONFIG_NUMA */ 6222 6223static int __sdt_alloc(const struct cpumask *cpu_map) 6224{ 6225 struct sched_domain_topology_level *tl; 6226 int j; 6227 6228 for_each_sd_topology(tl) { 6229 struct sd_data *sdd = &tl->data; 6230 6231 sdd->sd = alloc_percpu(struct sched_domain *); 6232 if (!sdd->sd) 6233 return -ENOMEM; 6234 6235 sdd->sg = alloc_percpu(struct sched_group *); 6236 if (!sdd->sg) 6237 return -ENOMEM; 6238 6239 sdd->sgp = alloc_percpu(struct sched_group_power *); 6240 if (!sdd->sgp) 6241 return -ENOMEM; 6242 6243 for_each_cpu(j, cpu_map) { 6244 struct sched_domain *sd; 6245 struct sched_group *sg; 6246 struct sched_group_power *sgp; 6247 6248 sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(), 6249 GFP_KERNEL, cpu_to_node(j)); 6250 if (!sd) 6251 return -ENOMEM; 6252 6253 *per_cpu_ptr(sdd->sd, j) = sd; 6254 6255 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), 6256 GFP_KERNEL, cpu_to_node(j)); 6257 if (!sg) 6258 return -ENOMEM; 6259 6260 sg->next = sg; 6261 6262 *per_cpu_ptr(sdd->sg, j) = sg; 6263 6264 sgp = kzalloc_node(sizeof(struct sched_group_power) + cpumask_size(), 6265 GFP_KERNEL, cpu_to_node(j)); 6266 if (!sgp) 6267 return -ENOMEM; 6268 6269 *per_cpu_ptr(sdd->sgp, j) = sgp; 6270 } 6271 } 6272 6273 return 0; 6274} 6275 6276static void __sdt_free(const struct cpumask *cpu_map) 6277{ 6278 struct sched_domain_topology_level *tl; 6279 int j; 6280 6281 for_each_sd_topology(tl) { 6282 struct sd_data *sdd = &tl->data; 6283 6284 for_each_cpu(j, cpu_map) { 6285 struct sched_domain *sd; 6286 6287 if (sdd->sd) { 6288 sd = *per_cpu_ptr(sdd->sd, j); 6289 if (sd && (sd->flags & SD_OVERLAP)) 6290 free_sched_groups(sd->groups, 0); 6291 kfree(*per_cpu_ptr(sdd->sd, j)); 6292 } 6293 6294 if (sdd->sg) 6295 kfree(*per_cpu_ptr(sdd->sg, j)); 6296 if (sdd->sgp) 6297 kfree(*per_cpu_ptr(sdd->sgp, j)); 6298 } 6299 free_percpu(sdd->sd); 6300 sdd->sd = NULL; 6301 free_percpu(sdd->sg); 6302 sdd->sg = NULL; 6303 free_percpu(sdd->sgp); 6304 sdd->sgp = NULL; 6305 } 6306} 6307 6308struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl, 6309 const struct cpumask *cpu_map, struct sched_domain_attr *attr, 6310 struct sched_domain *child, int cpu) 6311{ 6312 struct sched_domain *sd = tl->init(tl, cpu); 6313 if (!sd) 6314 return child; 6315 6316 cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu)); 6317 if (child) { 6318 sd->level = child->level + 1; 6319 sched_domain_level_max = max(sched_domain_level_max, sd->level); 6320 child->parent = sd; 6321 sd->child = child; 6322 } 6323 set_domain_attribute(sd, attr); 6324 6325 return sd; 6326} 6327 6328/* 6329 * Build sched domains for a given set of cpus and attach the sched domains 6330 * to the individual cpus 6331 */ 6332static int build_sched_domains(const struct cpumask *cpu_map, 6333 struct sched_domain_attr *attr) 6334{ 6335 enum s_alloc alloc_state; 6336 struct sched_domain *sd; 6337 struct s_data d; 6338 int i, ret = -ENOMEM; 6339 6340 alloc_state = __visit_domain_allocation_hell(&d, cpu_map); 6341 if (alloc_state != sa_rootdomain) 6342 goto error; 6343 6344 /* Set up domains for cpus specified by the cpu_map. */ 6345 for_each_cpu(i, cpu_map) { 6346 struct sched_domain_topology_level *tl; 6347 6348 sd = NULL; 6349 for_each_sd_topology(tl) { 6350 sd = build_sched_domain(tl, cpu_map, attr, sd, i); 6351 if (tl == sched_domain_topology) 6352 *per_cpu_ptr(d.sd, i) = sd; 6353 if (tl->flags & SDTL_OVERLAP || sched_feat(FORCE_SD_OVERLAP)) 6354 sd->flags |= SD_OVERLAP; 6355 if (cpumask_equal(cpu_map, sched_domain_span(sd))) 6356 break; 6357 } 6358 } 6359 6360 /* Build the groups for the domains */ 6361 for_each_cpu(i, cpu_map) { 6362 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { 6363 sd->span_weight = cpumask_weight(sched_domain_span(sd)); 6364 if (sd->flags & SD_OVERLAP) { 6365 if (build_overlap_sched_groups(sd, i)) 6366 goto error; 6367 } else { 6368 if (build_sched_groups(sd, i)) 6369 goto error; 6370 } 6371 } 6372 } 6373 6374 /* Calculate CPU power for physical packages and nodes */ 6375 for (i = nr_cpumask_bits-1; i >= 0; i--) { 6376 if (!cpumask_test_cpu(i, cpu_map)) 6377 continue; 6378 6379 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { 6380 claim_allocations(i, sd); 6381 init_sched_groups_power(i, sd); 6382 } 6383 } 6384 6385 /* Attach the domains */ 6386 rcu_read_lock(); 6387 for_each_cpu(i, cpu_map) { 6388 sd = *per_cpu_ptr(d.sd, i); 6389 cpu_attach_domain(sd, d.rd, i); 6390 } 6391 rcu_read_unlock(); 6392 6393 ret = 0; 6394error: 6395 __free_domain_allocs(&d, alloc_state, cpu_map); 6396 return ret; 6397} 6398 6399static cpumask_var_t *doms_cur; /* current sched domains */ 6400static int ndoms_cur; /* number of sched domains in 'doms_cur' */ 6401static struct sched_domain_attr *dattr_cur; 6402 /* attribues of custom domains in 'doms_cur' */ 6403 6404/* 6405 * Special case: If a kmalloc of a doms_cur partition (array of 6406 * cpumask) fails, then fallback to a single sched domain, 6407 * as determined by the single cpumask fallback_doms. 6408 */ 6409static cpumask_var_t fallback_doms; 6410 6411/* 6412 * arch_update_cpu_topology lets virtualized architectures update the 6413 * cpu core maps. It is supposed to return 1 if the topology changed 6414 * or 0 if it stayed the same. 6415 */ 6416int __attribute__((weak)) arch_update_cpu_topology(void) 6417{ 6418 return 0; 6419} 6420 6421cpumask_var_t *alloc_sched_domains(unsigned int ndoms) 6422{ 6423 int i; 6424 cpumask_var_t *doms; 6425 6426 doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL); 6427 if (!doms) 6428 return NULL; 6429 for (i = 0; i < ndoms; i++) { 6430 if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) { 6431 free_sched_domains(doms, i); 6432 return NULL; 6433 } 6434 } 6435 return doms; 6436} 6437 6438void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms) 6439{ 6440 unsigned int i; 6441 for (i = 0; i < ndoms; i++) 6442 free_cpumask_var(doms[i]); 6443 kfree(doms); 6444} 6445 6446/* 6447 * Set up scheduler domains and groups. Callers must hold the hotplug lock. 6448 * For now this just excludes isolated cpus, but could be used to 6449 * exclude other special cases in the future. 6450 */ 6451static int init_sched_domains(const struct cpumask *cpu_map) 6452{ 6453 int err; 6454 6455 arch_update_cpu_topology(); 6456 ndoms_cur = 1; 6457 doms_cur = alloc_sched_domains(ndoms_cur); 6458 if (!doms_cur) 6459 doms_cur = &fallback_doms; 6460 cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map); 6461 err = build_sched_domains(doms_cur[0], NULL); 6462 register_sched_domain_sysctl(); 6463 6464 return err; 6465} 6466 6467/* 6468 * Detach sched domains from a group of cpus specified in cpu_map 6469 * These cpus will now be attached to the NULL domain 6470 */ 6471static void detach_destroy_domains(const struct cpumask *cpu_map) 6472{ 6473 int i; 6474 6475 rcu_read_lock(); 6476 for_each_cpu(i, cpu_map) 6477 cpu_attach_domain(NULL, &def_root_domain, i); 6478 rcu_read_unlock(); 6479} 6480 6481/* handle null as "default" */ 6482static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur, 6483 struct sched_domain_attr *new, int idx_new) 6484{ 6485 struct sched_domain_attr tmp; 6486 6487 /* fast path */ 6488 if (!new && !cur) 6489 return 1; 6490 6491 tmp = SD_ATTR_INIT; 6492 return !memcmp(cur ? (cur + idx_cur) : &tmp, 6493 new ? (new + idx_new) : &tmp, 6494 sizeof(struct sched_domain_attr)); 6495} 6496 6497/* 6498 * Partition sched domains as specified by the 'ndoms_new' 6499 * cpumasks in the array doms_new[] of cpumasks. This compares 6500 * doms_new[] to the current sched domain partitioning, doms_cur[]. 6501 * It destroys each deleted domain and builds each new domain. 6502 * 6503 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'. 6504 * The masks don't intersect (don't overlap.) We should setup one 6505 * sched domain for each mask. CPUs not in any of the cpumasks will 6506 * not be load balanced. If the same cpumask appears both in the 6507 * current 'doms_cur' domains and in the new 'doms_new', we can leave 6508 * it as it is. 6509 * 6510 * The passed in 'doms_new' should be allocated using 6511 * alloc_sched_domains. This routine takes ownership of it and will 6512 * free_sched_domains it when done with it. If the caller failed the 6513 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1, 6514 * and partition_sched_domains() will fallback to the single partition 6515 * 'fallback_doms', it also forces the domains to be rebuilt. 6516 * 6517 * If doms_new == NULL it will be replaced with cpu_online_mask. 6518 * ndoms_new == 0 is a special case for destroying existing domains, 6519 * and it will not create the default domain. 6520 * 6521 * Call with hotplug lock held 6522 */ 6523void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[], 6524 struct sched_domain_attr *dattr_new) 6525{ 6526 int i, j, n; 6527 int new_topology; 6528 6529 mutex_lock(&sched_domains_mutex); 6530 6531 /* always unregister in case we don't destroy any domains */ 6532 unregister_sched_domain_sysctl(); 6533 6534 /* Let architecture update cpu core mappings. */ 6535 new_topology = arch_update_cpu_topology(); 6536 6537 n = doms_new ? ndoms_new : 0; 6538 6539 /* Destroy deleted domains */ 6540 for (i = 0; i < ndoms_cur; i++) { 6541 for (j = 0; j < n && !new_topology; j++) { 6542 if (cpumask_equal(doms_cur[i], doms_new[j]) 6543 && dattrs_equal(dattr_cur, i, dattr_new, j)) 6544 goto match1; 6545 } 6546 /* no match - a current sched domain not in new doms_new[] */ 6547 detach_destroy_domains(doms_cur[i]); 6548match1: 6549 ; 6550 } 6551 6552 n = ndoms_cur; 6553 if (doms_new == NULL) { 6554 n = 0; 6555 doms_new = &fallback_doms; 6556 cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map); 6557 WARN_ON_ONCE(dattr_new); 6558 } 6559 6560 /* Build new domains */ 6561 for (i = 0; i < ndoms_new; i++) { 6562 for (j = 0; j < n && !new_topology; j++) { 6563 if (cpumask_equal(doms_new[i], doms_cur[j]) 6564 && dattrs_equal(dattr_new, i, dattr_cur, j)) 6565 goto match2; 6566 } 6567 /* no match - add a new doms_new */ 6568 build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL); 6569match2: 6570 ; 6571 } 6572 6573 /* Remember the new sched domains */ 6574 if (doms_cur != &fallback_doms) 6575 free_sched_domains(doms_cur, ndoms_cur); 6576 kfree(dattr_cur); /* kfree(NULL) is safe */ 6577 doms_cur = doms_new; 6578 dattr_cur = dattr_new; 6579 ndoms_cur = ndoms_new; 6580 6581 register_sched_domain_sysctl(); 6582 6583 mutex_unlock(&sched_domains_mutex); 6584} 6585 6586static int num_cpus_frozen; /* used to mark begin/end of suspend/resume */ 6587 6588/* 6589 * Update cpusets according to cpu_active mask. If cpusets are 6590 * disabled, cpuset_update_active_cpus() becomes a simple wrapper 6591 * around partition_sched_domains(). 6592 * 6593 * If we come here as part of a suspend/resume, don't touch cpusets because we 6594 * want to restore it back to its original state upon resume anyway. 6595 */ 6596static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action, 6597 void *hcpu) 6598{ 6599 switch (action) { 6600 case CPU_ONLINE_FROZEN: 6601 case CPU_DOWN_FAILED_FROZEN: 6602 6603 /* 6604 * num_cpus_frozen tracks how many CPUs are involved in suspend 6605 * resume sequence. As long as this is not the last online 6606 * operation in the resume sequence, just build a single sched 6607 * domain, ignoring cpusets. 6608 */ 6609 num_cpus_frozen--; 6610 if (likely(num_cpus_frozen)) { 6611 partition_sched_domains(1, NULL, NULL); 6612 break; 6613 } 6614 6615 /* 6616 * This is the last CPU online operation. So fall through and 6617 * restore the original sched domains by considering the 6618 * cpuset configurations. 6619 */ 6620 6621 case CPU_ONLINE: 6622 case CPU_DOWN_FAILED: 6623 cpuset_update_active_cpus(true); 6624 break; 6625 default: 6626 return NOTIFY_DONE; 6627 } 6628 return NOTIFY_OK; 6629} 6630 6631static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action, 6632 void *hcpu) 6633{ 6634 switch (action) { 6635 case CPU_DOWN_PREPARE: 6636 cpuset_update_active_cpus(false); 6637 break; 6638 case CPU_DOWN_PREPARE_FROZEN: 6639 num_cpus_frozen++; 6640 partition_sched_domains(1, NULL, NULL); 6641 break; 6642 default: 6643 return NOTIFY_DONE; 6644 } 6645 return NOTIFY_OK; 6646} 6647 6648void __init sched_init_smp(void) 6649{ 6650 cpumask_var_t non_isolated_cpus; 6651 6652 alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL); 6653 alloc_cpumask_var(&fallback_doms, GFP_KERNEL); 6654 6655 sched_init_numa(); 6656 6657 /* 6658 * There's no userspace yet to cause hotplug operations; hence all the 6659 * cpu masks are stable and all blatant races in the below code cannot 6660 * happen. 6661 */ 6662 mutex_lock(&sched_domains_mutex); 6663 init_sched_domains(cpu_active_mask); 6664 cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map); 6665 if (cpumask_empty(non_isolated_cpus)) 6666 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus); 6667 mutex_unlock(&sched_domains_mutex); 6668 6669 hotcpu_notifier(sched_domains_numa_masks_update, CPU_PRI_SCHED_ACTIVE); 6670 hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE); 6671 hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE); 6672 6673 init_hrtick(); 6674 6675 /* Move init over to a non-isolated CPU */ 6676 if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0) 6677 BUG(); 6678 sched_init_granularity(); 6679 free_cpumask_var(non_isolated_cpus); 6680 6681 init_sched_rt_class(); 6682 init_sched_dl_class(); 6683} 6684#else 6685void __init sched_init_smp(void) 6686{ 6687 sched_init_granularity(); 6688} 6689#endif /* CONFIG_SMP */ 6690 6691const_debug unsigned int sysctl_timer_migration = 1; 6692 6693int in_sched_functions(unsigned long addr) 6694{ 6695 return in_lock_functions(addr) || 6696 (addr >= (unsigned long)__sched_text_start 6697 && addr < (unsigned long)__sched_text_end); 6698} 6699 6700#ifdef CONFIG_CGROUP_SCHED 6701/* 6702 * Default task group. 6703 * Every task in system belongs to this group at bootup. 6704 */ 6705struct task_group root_task_group; 6706LIST_HEAD(task_groups); 6707#endif 6708 6709DECLARE_PER_CPU(cpumask_var_t, load_balance_mask); 6710 6711void __init sched_init(void) 6712{ 6713 int i, j; 6714 unsigned long alloc_size = 0, ptr; 6715 6716#ifdef CONFIG_FAIR_GROUP_SCHED 6717 alloc_size += 2 * nr_cpu_ids * sizeof(void **); 6718#endif 6719#ifdef CONFIG_RT_GROUP_SCHED 6720 alloc_size += 2 * nr_cpu_ids * sizeof(void **); 6721#endif 6722#ifdef CONFIG_CPUMASK_OFFSTACK 6723 alloc_size += num_possible_cpus() * cpumask_size(); 6724#endif 6725 if (alloc_size) { 6726 ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT); 6727 6728#ifdef CONFIG_FAIR_GROUP_SCHED 6729 root_task_group.se = (struct sched_entity **)ptr; 6730 ptr += nr_cpu_ids * sizeof(void **); 6731 6732 root_task_group.cfs_rq = (struct cfs_rq **)ptr; 6733 ptr += nr_cpu_ids * sizeof(void **); 6734 6735#endif /* CONFIG_FAIR_GROUP_SCHED */ 6736#ifdef CONFIG_RT_GROUP_SCHED 6737 root_task_group.rt_se = (struct sched_rt_entity **)ptr; 6738 ptr += nr_cpu_ids * sizeof(void **); 6739 6740 root_task_group.rt_rq = (struct rt_rq **)ptr; 6741 ptr += nr_cpu_ids * sizeof(void **); 6742 6743#endif /* CONFIG_RT_GROUP_SCHED */ 6744#ifdef CONFIG_CPUMASK_OFFSTACK 6745 for_each_possible_cpu(i) { 6746 per_cpu(load_balance_mask, i) = (void *)ptr; 6747 ptr += cpumask_size(); 6748 } 6749#endif /* CONFIG_CPUMASK_OFFSTACK */ 6750 } 6751 6752 init_rt_bandwidth(&def_rt_bandwidth, 6753 global_rt_period(), global_rt_runtime()); 6754 init_dl_bandwidth(&def_dl_bandwidth, 6755 global_rt_period(), global_rt_runtime()); 6756 6757#ifdef CONFIG_SMP 6758 init_defrootdomain(); 6759#endif 6760 6761#ifdef CONFIG_RT_GROUP_SCHED 6762 init_rt_bandwidth(&root_task_group.rt_bandwidth, 6763 global_rt_period(), global_rt_runtime()); 6764#endif /* CONFIG_RT_GROUP_SCHED */ 6765 6766#ifdef CONFIG_CGROUP_SCHED 6767 list_add(&root_task_group.list, &task_groups); 6768 INIT_LIST_HEAD(&root_task_group.children); 6769 INIT_LIST_HEAD(&root_task_group.siblings); 6770 autogroup_init(&init_task); 6771 6772#endif /* CONFIG_CGROUP_SCHED */ 6773 6774 for_each_possible_cpu(i) { 6775 struct rq *rq; 6776 6777 rq = cpu_rq(i); 6778 raw_spin_lock_init(&rq->lock); 6779 rq->nr_running = 0; 6780 rq->calc_load_active = 0; 6781 rq->calc_load_update = jiffies + LOAD_FREQ; 6782 init_cfs_rq(&rq->cfs); 6783 init_rt_rq(&rq->rt, rq); 6784 init_dl_rq(&rq->dl, rq); 6785#ifdef CONFIG_FAIR_GROUP_SCHED 6786 root_task_group.shares = ROOT_TASK_GROUP_LOAD; 6787 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list); 6788 /* 6789 * How much cpu bandwidth does root_task_group get? 6790 * 6791 * In case of task-groups formed thr' the cgroup filesystem, it 6792 * gets 100% of the cpu resources in the system. This overall 6793 * system cpu resource is divided among the tasks of 6794 * root_task_group and its child task-groups in a fair manner, 6795 * based on each entity's (task or task-group's) weight 6796 * (se->load.weight). 6797 * 6798 * In other words, if root_task_group has 10 tasks of weight 6799 * 1024) and two child groups A0 and A1 (of weight 1024 each), 6800 * then A0's share of the cpu resource is: 6801 * 6802 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33% 6803 * 6804 * We achieve this by letting root_task_group's tasks sit 6805 * directly in rq->cfs (i.e root_task_group->se[] = NULL). 6806 */ 6807 init_cfs_bandwidth(&root_task_group.cfs_bandwidth); 6808 init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL); 6809#endif /* CONFIG_FAIR_GROUP_SCHED */ 6810 6811 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime; 6812#ifdef CONFIG_RT_GROUP_SCHED 6813 INIT_LIST_HEAD(&rq->leaf_rt_rq_list); 6814 init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL); 6815#endif 6816 6817 for (j = 0; j < CPU_LOAD_IDX_MAX; j++) 6818 rq->cpu_load[j] = 0; 6819 6820 rq->last_load_update_tick = jiffies; 6821 6822#ifdef CONFIG_SMP 6823 rq->sd = NULL; 6824 rq->rd = NULL; 6825 rq->cpu_power = SCHED_POWER_SCALE; 6826 rq->post_schedule = 0; 6827 rq->active_balance = 0; 6828 rq->next_balance = jiffies; 6829 rq->push_cpu = 0; 6830 rq->cpu = i; 6831 rq->online = 0; 6832 rq->idle_stamp = 0; 6833 rq->avg_idle = 2*sysctl_sched_migration_cost; 6834 rq->max_idle_balance_cost = sysctl_sched_migration_cost; 6835 6836 INIT_LIST_HEAD(&rq->cfs_tasks); 6837 6838 rq_attach_root(rq, &def_root_domain); 6839#ifdef CONFIG_NO_HZ_COMMON 6840 rq->nohz_flags = 0; 6841#endif 6842#ifdef CONFIG_NO_HZ_FULL 6843 rq->last_sched_tick = 0; 6844#endif 6845#endif 6846 init_rq_hrtick(rq); 6847 atomic_set(&rq->nr_iowait, 0); 6848 } 6849 6850 set_load_weight(&init_task); 6851 6852#ifdef CONFIG_PREEMPT_NOTIFIERS 6853 INIT_HLIST_HEAD(&init_task.preempt_notifiers); 6854#endif 6855 6856 /* 6857 * The boot idle thread does lazy MMU switching as well: 6858 */ 6859 atomic_inc(&init_mm.mm_count); 6860 enter_lazy_tlb(&init_mm, current); 6861 6862 /* 6863 * Make us the idle thread. Technically, schedule() should not be 6864 * called from this thread, however somewhere below it might be, 6865 * but because we are the idle thread, we just pick up running again 6866 * when this runqueue becomes "idle". 6867 */ 6868 init_idle(current, smp_processor_id()); 6869 6870 calc_load_update = jiffies + LOAD_FREQ; 6871 6872 /* 6873 * During early bootup we pretend to be a normal task: 6874 */ 6875 current->sched_class = &fair_sched_class; 6876 6877#ifdef CONFIG_SMP 6878 zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT); 6879 /* May be allocated at isolcpus cmdline parse time */ 6880 if (cpu_isolated_map == NULL) 6881 zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT); 6882 idle_thread_set_boot_cpu(); 6883#endif 6884 init_sched_fair_class(); 6885 6886 scheduler_running = 1; 6887} 6888 6889#ifdef CONFIG_DEBUG_ATOMIC_SLEEP 6890static inline int preempt_count_equals(int preempt_offset) 6891{ 6892 int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth(); 6893 6894 return (nested == preempt_offset); 6895} 6896 6897void __might_sleep(const char *file, int line, int preempt_offset) 6898{ 6899 static unsigned long prev_jiffy; /* ratelimiting */ 6900 6901 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */ 6902 if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) || 6903 system_state != SYSTEM_RUNNING || oops_in_progress) 6904 return; 6905 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) 6906 return; 6907 prev_jiffy = jiffies; 6908 6909 printk(KERN_ERR 6910 "BUG: sleeping function called from invalid context at %s:%d\n", 6911 file, line); 6912 printk(KERN_ERR 6913 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n", 6914 in_atomic(), irqs_disabled(), 6915 current->pid, current->comm); 6916 6917 debug_show_held_locks(current); 6918 if (irqs_disabled()) 6919 print_irqtrace_events(current); 6920 dump_stack(); 6921} 6922EXPORT_SYMBOL(__might_sleep); 6923#endif 6924 6925#ifdef CONFIG_MAGIC_SYSRQ 6926static void normalize_task(struct rq *rq, struct task_struct *p) 6927{ 6928 const struct sched_class *prev_class = p->sched_class; 6929 struct sched_attr attr = { 6930 .sched_policy = SCHED_NORMAL, 6931 }; 6932 int old_prio = p->prio; 6933 int on_rq; 6934 6935 on_rq = p->on_rq; 6936 if (on_rq) 6937 dequeue_task(rq, p, 0); 6938 __setscheduler(rq, p, &attr); 6939 if (on_rq) { 6940 enqueue_task(rq, p, 0); 6941 resched_task(rq->curr); 6942 } 6943 6944 check_class_changed(rq, p, prev_class, old_prio); 6945} 6946 6947void normalize_rt_tasks(void) 6948{ 6949 struct task_struct *g, *p; 6950 unsigned long flags; 6951 struct rq *rq; 6952 6953 read_lock_irqsave(&tasklist_lock, flags); 6954 do_each_thread(g, p) { 6955 /* 6956 * Only normalize user tasks: 6957 */ 6958 if (!p->mm) 6959 continue; 6960 6961 p->se.exec_start = 0; 6962#ifdef CONFIG_SCHEDSTATS 6963 p->se.statistics.wait_start = 0; 6964 p->se.statistics.sleep_start = 0; 6965 p->se.statistics.block_start = 0; 6966#endif 6967 6968 if (!dl_task(p) && !rt_task(p)) { 6969 /* 6970 * Renice negative nice level userspace 6971 * tasks back to 0: 6972 */ 6973 if (TASK_NICE(p) < 0 && p->mm) 6974 set_user_nice(p, 0); 6975 continue; 6976 } 6977 6978 raw_spin_lock(&p->pi_lock); 6979 rq = __task_rq_lock(p); 6980 6981 normalize_task(rq, p); 6982 6983 __task_rq_unlock(rq); 6984 raw_spin_unlock(&p->pi_lock); 6985 } while_each_thread(g, p); 6986 6987 read_unlock_irqrestore(&tasklist_lock, flags); 6988} 6989 6990#endif /* CONFIG_MAGIC_SYSRQ */ 6991 6992#if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) 6993/* 6994 * These functions are only useful for the IA64 MCA handling, or kdb. 6995 * 6996 * They can only be called when the whole system has been 6997 * stopped - every CPU needs to be quiescent, and no scheduling 6998 * activity can take place. Using them for anything else would 6999 * be a serious bug, and as a result, they aren't even visible 7000 * under any other configuration. 7001 */ 7002 7003/** 7004 * curr_task - return the current task for a given cpu. 7005 * @cpu: the processor in question. 7006 * 7007 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! 7008 * 7009 * Return: The current task for @cpu. 7010 */ 7011struct task_struct *curr_task(int cpu) 7012{ 7013 return cpu_curr(cpu); 7014} 7015 7016#endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */ 7017 7018#ifdef CONFIG_IA64 7019/** 7020 * set_curr_task - set the current task for a given cpu. 7021 * @cpu: the processor in question. 7022 * @p: the task pointer to set. 7023 * 7024 * Description: This function must only be used when non-maskable interrupts 7025 * are serviced on a separate stack. It allows the architecture to switch the 7026 * notion of the current task on a cpu in a non-blocking manner. This function 7027 * must be called with all CPU's synchronized, and interrupts disabled, the 7028 * and caller must save the original value of the current task (see 7029 * curr_task() above) and restore that value before reenabling interrupts and 7030 * re-starting the system. 7031 * 7032 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! 7033 */ 7034void set_curr_task(int cpu, struct task_struct *p) 7035{ 7036 cpu_curr(cpu) = p; 7037} 7038 7039#endif 7040 7041#ifdef CONFIG_CGROUP_SCHED 7042/* task_group_lock serializes the addition/removal of task groups */ 7043static DEFINE_SPINLOCK(task_group_lock); 7044 7045static void free_sched_group(struct task_group *tg) 7046{ 7047 free_fair_sched_group(tg); 7048 free_rt_sched_group(tg); 7049 autogroup_free(tg); 7050 kfree(tg); 7051} 7052 7053/* allocate runqueue etc for a new task group */ 7054struct task_group *sched_create_group(struct task_group *parent) 7055{ 7056 struct task_group *tg; 7057 7058 tg = kzalloc(sizeof(*tg), GFP_KERNEL); 7059 if (!tg) 7060 return ERR_PTR(-ENOMEM); 7061 7062 if (!alloc_fair_sched_group(tg, parent)) 7063 goto err; 7064 7065 if (!alloc_rt_sched_group(tg, parent)) 7066 goto err; 7067 7068 return tg; 7069 7070err: 7071 free_sched_group(tg); 7072 return ERR_PTR(-ENOMEM); 7073} 7074 7075void sched_online_group(struct task_group *tg, struct task_group *parent) 7076{ 7077 unsigned long flags; 7078 7079 spin_lock_irqsave(&task_group_lock, flags); 7080 list_add_rcu(&tg->list, &task_groups); 7081 7082 WARN_ON(!parent); /* root should already exist */ 7083 7084 tg->parent = parent; 7085 INIT_LIST_HEAD(&tg->children); 7086 list_add_rcu(&tg->siblings, &parent->children); 7087 spin_unlock_irqrestore(&task_group_lock, flags); 7088} 7089 7090/* rcu callback to free various structures associated with a task group */ 7091static void free_sched_group_rcu(struct rcu_head *rhp) 7092{ 7093 /* now it should be safe to free those cfs_rqs */ 7094 free_sched_group(container_of(rhp, struct task_group, rcu)); 7095} 7096 7097/* Destroy runqueue etc associated with a task group */ 7098void sched_destroy_group(struct task_group *tg) 7099{ 7100 /* wait for possible concurrent references to cfs_rqs complete */ 7101 call_rcu(&tg->rcu, free_sched_group_rcu); 7102} 7103 7104void sched_offline_group(struct task_group *tg) 7105{ 7106 unsigned long flags; 7107 int i; 7108 7109 /* end participation in shares distribution */ 7110 for_each_possible_cpu(i) 7111 unregister_fair_sched_group(tg, i); 7112 7113 spin_lock_irqsave(&task_group_lock, flags); 7114 list_del_rcu(&tg->list); 7115 list_del_rcu(&tg->siblings); 7116 spin_unlock_irqrestore(&task_group_lock, flags); 7117} 7118 7119/* change task's runqueue when it moves between groups. 7120 * The caller of this function should have put the task in its new group 7121 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to 7122 * reflect its new group. 7123 */ 7124void sched_move_task(struct task_struct *tsk) 7125{ 7126 struct task_group *tg; 7127 int on_rq, running; 7128 unsigned long flags; 7129 struct rq *rq; 7130 7131 rq = task_rq_lock(tsk, &flags); 7132 7133 running = task_current(rq, tsk); 7134 on_rq = tsk->on_rq; 7135 7136 if (on_rq) 7137 dequeue_task(rq, tsk, 0); 7138 if (unlikely(running)) 7139 tsk->sched_class->put_prev_task(rq, tsk); 7140 7141 tg = container_of(task_css_check(tsk, cpu_cgroup_subsys_id, 7142 lockdep_is_held(&tsk->sighand->siglock)), 7143 struct task_group, css); 7144 tg = autogroup_task_group(tsk, tg); 7145 tsk->sched_task_group = tg; 7146 7147#ifdef CONFIG_FAIR_GROUP_SCHED 7148 if (tsk->sched_class->task_move_group) 7149 tsk->sched_class->task_move_group(tsk, on_rq); 7150 else 7151#endif 7152 set_task_rq(tsk, task_cpu(tsk)); 7153 7154 if (unlikely(running)) 7155 tsk->sched_class->set_curr_task(rq); 7156 if (on_rq) 7157 enqueue_task(rq, tsk, 0); 7158 7159 task_rq_unlock(rq, tsk, &flags); 7160} 7161#endif /* CONFIG_CGROUP_SCHED */ 7162 7163#ifdef CONFIG_RT_GROUP_SCHED 7164/* 7165 * Ensure that the real time constraints are schedulable. 7166 */ 7167static DEFINE_MUTEX(rt_constraints_mutex); 7168 7169/* Must be called with tasklist_lock held */ 7170static inline int tg_has_rt_tasks(struct task_group *tg) 7171{ 7172 struct task_struct *g, *p; 7173 7174 do_each_thread(g, p) { 7175 if (rt_task(p) && task_rq(p)->rt.tg == tg) 7176 return 1; 7177 } while_each_thread(g, p); 7178 7179 return 0; 7180} 7181 7182struct rt_schedulable_data { 7183 struct task_group *tg; 7184 u64 rt_period; 7185 u64 rt_runtime; 7186}; 7187 7188static int tg_rt_schedulable(struct task_group *tg, void *data) 7189{ 7190 struct rt_schedulable_data *d = data; 7191 struct task_group *child; 7192 unsigned long total, sum = 0; 7193 u64 period, runtime; 7194 7195 period = ktime_to_ns(tg->rt_bandwidth.rt_period); 7196 runtime = tg->rt_bandwidth.rt_runtime; 7197 7198 if (tg == d->tg) { 7199 period = d->rt_period; 7200 runtime = d->rt_runtime; 7201 } 7202 7203 /* 7204 * Cannot have more runtime than the period. 7205 */ 7206 if (runtime > period && runtime != RUNTIME_INF) 7207 return -EINVAL; 7208 7209 /* 7210 * Ensure we don't starve existing RT tasks. 7211 */ 7212 if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg)) 7213 return -EBUSY; 7214 7215 total = to_ratio(period, runtime); 7216 7217 /* 7218 * Nobody can have more than the global setting allows. 7219 */ 7220 if (total > to_ratio(global_rt_period(), global_rt_runtime())) 7221 return -EINVAL; 7222 7223 /* 7224 * The sum of our children's runtime should not exceed our own. 7225 */ 7226 list_for_each_entry_rcu(child, &tg->children, siblings) { 7227 period = ktime_to_ns(child->rt_bandwidth.rt_period); 7228 runtime = child->rt_bandwidth.rt_runtime; 7229 7230 if (child == d->tg) { 7231 period = d->rt_period; 7232 runtime = d->rt_runtime; 7233 } 7234 7235 sum += to_ratio(period, runtime); 7236 } 7237 7238 if (sum > total) 7239 return -EINVAL; 7240 7241 return 0; 7242} 7243 7244static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime) 7245{ 7246 int ret; 7247 7248 struct rt_schedulable_data data = { 7249 .tg = tg, 7250 .rt_period = period, 7251 .rt_runtime = runtime, 7252 }; 7253 7254 rcu_read_lock(); 7255 ret = walk_tg_tree(tg_rt_schedulable, tg_nop, &data); 7256 rcu_read_unlock(); 7257 7258 return ret; 7259} 7260 7261static int tg_set_rt_bandwidth(struct task_group *tg, 7262 u64 rt_period, u64 rt_runtime) 7263{ 7264 int i, err = 0; 7265 7266 mutex_lock(&rt_constraints_mutex); 7267 read_lock(&tasklist_lock); 7268 err = __rt_schedulable(tg, rt_period, rt_runtime); 7269 if (err) 7270 goto unlock; 7271 7272 raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock); 7273 tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period); 7274 tg->rt_bandwidth.rt_runtime = rt_runtime; 7275 7276 for_each_possible_cpu(i) { 7277 struct rt_rq *rt_rq = tg->rt_rq[i]; 7278 7279 raw_spin_lock(&rt_rq->rt_runtime_lock); 7280 rt_rq->rt_runtime = rt_runtime; 7281 raw_spin_unlock(&rt_rq->rt_runtime_lock); 7282 } 7283 raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock); 7284unlock: 7285 read_unlock(&tasklist_lock); 7286 mutex_unlock(&rt_constraints_mutex); 7287 7288 return err; 7289} 7290 7291static int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us) 7292{ 7293 u64 rt_runtime, rt_period; 7294 7295 rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period); 7296 rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC; 7297 if (rt_runtime_us < 0) 7298 rt_runtime = RUNTIME_INF; 7299 7300 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); 7301} 7302 7303static long sched_group_rt_runtime(struct task_group *tg) 7304{ 7305 u64 rt_runtime_us; 7306 7307 if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF) 7308 return -1; 7309 7310 rt_runtime_us = tg->rt_bandwidth.rt_runtime; 7311 do_div(rt_runtime_us, NSEC_PER_USEC); 7312 return rt_runtime_us; 7313} 7314 7315static int sched_group_set_rt_period(struct task_group *tg, long rt_period_us) 7316{ 7317 u64 rt_runtime, rt_period; 7318 7319 rt_period = (u64)rt_period_us * NSEC_PER_USEC; 7320 rt_runtime = tg->rt_bandwidth.rt_runtime; 7321 7322 if (rt_period == 0) 7323 return -EINVAL; 7324 7325 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); 7326} 7327 7328static long sched_group_rt_period(struct task_group *tg) 7329{ 7330 u64 rt_period_us; 7331 7332 rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period); 7333 do_div(rt_period_us, NSEC_PER_USEC); 7334 return rt_period_us; 7335} 7336#endif /* CONFIG_RT_GROUP_SCHED */ 7337 7338#ifdef CONFIG_RT_GROUP_SCHED 7339static int sched_rt_global_constraints(void) 7340{ 7341 int ret = 0; 7342 7343 mutex_lock(&rt_constraints_mutex); 7344 read_lock(&tasklist_lock); 7345 ret = __rt_schedulable(NULL, 0, 0); 7346 read_unlock(&tasklist_lock); 7347 mutex_unlock(&rt_constraints_mutex); 7348 7349 return ret; 7350} 7351 7352static int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk) 7353{ 7354 /* Don't accept realtime tasks when there is no way for them to run */ 7355 if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0) 7356 return 0; 7357 7358 return 1; 7359} 7360 7361#else /* !CONFIG_RT_GROUP_SCHED */ 7362static int sched_rt_global_constraints(void) 7363{ 7364 unsigned long flags; 7365 int i, ret = 0; 7366 7367 raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags); 7368 for_each_possible_cpu(i) { 7369 struct rt_rq *rt_rq = &cpu_rq(i)->rt; 7370 7371 raw_spin_lock(&rt_rq->rt_runtime_lock); 7372 rt_rq->rt_runtime = global_rt_runtime(); 7373 raw_spin_unlock(&rt_rq->rt_runtime_lock); 7374 } 7375 raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags); 7376 7377 return ret; 7378} 7379#endif /* CONFIG_RT_GROUP_SCHED */ 7380 7381static int sched_dl_global_constraints(void) 7382{ 7383 u64 runtime = global_rt_runtime(); 7384 u64 period = global_rt_period(); 7385 u64 new_bw = to_ratio(period, runtime); 7386 int cpu, ret = 0; 7387 7388 /* 7389 * Here we want to check the bandwidth not being set to some 7390 * value smaller than the currently allocated bandwidth in 7391 * any of the root_domains. 7392 * 7393 * FIXME: Cycling on all the CPUs is overdoing, but simpler than 7394 * cycling on root_domains... Discussion on different/better 7395 * solutions is welcome! 7396 */ 7397 for_each_possible_cpu(cpu) { 7398 struct dl_bw *dl_b = dl_bw_of(cpu); 7399 7400 raw_spin_lock(&dl_b->lock); 7401 if (new_bw < dl_b->total_bw) 7402 ret = -EBUSY; 7403 raw_spin_unlock(&dl_b->lock); 7404 7405 if (ret) 7406 break; 7407 } 7408 7409 return ret; 7410} 7411 7412static void sched_dl_do_global(void) 7413{ 7414 u64 new_bw = -1; 7415 int cpu; 7416 7417 def_dl_bandwidth.dl_period = global_rt_period(); 7418 def_dl_bandwidth.dl_runtime = global_rt_runtime(); 7419 7420 if (global_rt_runtime() != RUNTIME_INF) 7421 new_bw = to_ratio(global_rt_period(), global_rt_runtime()); 7422 7423 /* 7424 * FIXME: As above... 7425 */ 7426 for_each_possible_cpu(cpu) { 7427 struct dl_bw *dl_b = dl_bw_of(cpu); 7428 7429 raw_spin_lock(&dl_b->lock); 7430 dl_b->bw = new_bw; 7431 raw_spin_unlock(&dl_b->lock); 7432 } 7433} 7434 7435static int sched_rt_global_validate(void) 7436{ 7437 if (sysctl_sched_rt_period <= 0) 7438 return -EINVAL; 7439 7440 if (sysctl_sched_rt_runtime > sysctl_sched_rt_period) 7441 return -EINVAL; 7442 7443 return 0; 7444} 7445 7446static void sched_rt_do_global(void) 7447{ 7448 def_rt_bandwidth.rt_runtime = global_rt_runtime(); 7449 def_rt_bandwidth.rt_period = ns_to_ktime(global_rt_period()); 7450} 7451 7452int sched_rt_handler(struct ctl_table *table, int write, 7453 void __user *buffer, size_t *lenp, 7454 loff_t *ppos) 7455{ 7456 int old_period, old_runtime; 7457 static DEFINE_MUTEX(mutex); 7458 int ret; 7459 7460 mutex_lock(&mutex); 7461 old_period = sysctl_sched_rt_period; 7462 old_runtime = sysctl_sched_rt_runtime; 7463 7464 ret = proc_dointvec(table, write, buffer, lenp, ppos); 7465 7466 if (!ret && write) { 7467 ret = sched_rt_global_validate(); 7468 if (ret) 7469 goto undo; 7470 7471 ret = sched_rt_global_constraints(); 7472 if (ret) 7473 goto undo; 7474 7475 ret = sched_dl_global_constraints(); 7476 if (ret) 7477 goto undo; 7478 7479 sched_rt_do_global(); 7480 sched_dl_do_global(); 7481 } 7482 if (0) { 7483undo: 7484 sysctl_sched_rt_period = old_period; 7485 sysctl_sched_rt_runtime = old_runtime; 7486 } 7487 mutex_unlock(&mutex); 7488 7489 return ret; 7490} 7491 7492int sched_rr_handler(struct ctl_table *table, int write, 7493 void __user *buffer, size_t *lenp, 7494 loff_t *ppos) 7495{ 7496 int ret; 7497 static DEFINE_MUTEX(mutex); 7498 7499 mutex_lock(&mutex); 7500 ret = proc_dointvec(table, write, buffer, lenp, ppos); 7501 /* make sure that internally we keep jiffies */ 7502 /* also, writing zero resets timeslice to default */ 7503 if (!ret && write) { 7504 sched_rr_timeslice = sched_rr_timeslice <= 0 ? 7505 RR_TIMESLICE : msecs_to_jiffies(sched_rr_timeslice); 7506 } 7507 mutex_unlock(&mutex); 7508 return ret; 7509} 7510 7511#ifdef CONFIG_CGROUP_SCHED 7512 7513static inline struct task_group *css_tg(struct cgroup_subsys_state *css) 7514{ 7515 return css ? container_of(css, struct task_group, css) : NULL; 7516} 7517 7518static struct cgroup_subsys_state * 7519cpu_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) 7520{ 7521 struct task_group *parent = css_tg(parent_css); 7522 struct task_group *tg; 7523 7524 if (!parent) { 7525 /* This is early initialization for the top cgroup */ 7526 return &root_task_group.css; 7527 } 7528 7529 tg = sched_create_group(parent); 7530 if (IS_ERR(tg)) 7531 return ERR_PTR(-ENOMEM); 7532 7533 return &tg->css; 7534} 7535 7536static int cpu_cgroup_css_online(struct cgroup_subsys_state *css) 7537{ 7538 struct task_group *tg = css_tg(css); 7539 struct task_group *parent = css_tg(css_parent(css)); 7540 7541 if (parent) 7542 sched_online_group(tg, parent); 7543 return 0; 7544} 7545 7546static void cpu_cgroup_css_free(struct cgroup_subsys_state *css) 7547{ 7548 struct task_group *tg = css_tg(css); 7549 7550 sched_destroy_group(tg); 7551} 7552 7553static void cpu_cgroup_css_offline(struct cgroup_subsys_state *css) 7554{ 7555 struct task_group *tg = css_tg(css); 7556 7557 sched_offline_group(tg); 7558} 7559 7560static int cpu_cgroup_can_attach(struct cgroup_subsys_state *css, 7561 struct cgroup_taskset *tset) 7562{ 7563 struct task_struct *task; 7564 7565 cgroup_taskset_for_each(task, css, tset) { 7566#ifdef CONFIG_RT_GROUP_SCHED 7567 if (!sched_rt_can_attach(css_tg(css), task)) 7568 return -EINVAL; 7569#else 7570 /* We don't support RT-tasks being in separate groups */ 7571 if (task->sched_class != &fair_sched_class) 7572 return -EINVAL; 7573#endif 7574 } 7575 return 0; 7576} 7577 7578static void cpu_cgroup_attach(struct cgroup_subsys_state *css, 7579 struct cgroup_taskset *tset) 7580{ 7581 struct task_struct *task; 7582 7583 cgroup_taskset_for_each(task, css, tset) 7584 sched_move_task(task); 7585} 7586 7587static void cpu_cgroup_exit(struct cgroup_subsys_state *css, 7588 struct cgroup_subsys_state *old_css, 7589 struct task_struct *task) 7590{ 7591 /* 7592 * cgroup_exit() is called in the copy_process() failure path. 7593 * Ignore this case since the task hasn't ran yet, this avoids 7594 * trying to poke a half freed task state from generic code. 7595 */ 7596 if (!(task->flags & PF_EXITING)) 7597 return; 7598 7599 sched_move_task(task); 7600} 7601 7602#ifdef CONFIG_FAIR_GROUP_SCHED 7603static int cpu_shares_write_u64(struct cgroup_subsys_state *css, 7604 struct cftype *cftype, u64 shareval) 7605{ 7606 return sched_group_set_shares(css_tg(css), scale_load(shareval)); 7607} 7608 7609static u64 cpu_shares_read_u64(struct cgroup_subsys_state *css, 7610 struct cftype *cft) 7611{ 7612 struct task_group *tg = css_tg(css); 7613 7614 return (u64) scale_load_down(tg->shares); 7615} 7616 7617#ifdef CONFIG_CFS_BANDWIDTH 7618static DEFINE_MUTEX(cfs_constraints_mutex); 7619 7620const u64 max_cfs_quota_period = 1 * NSEC_PER_SEC; /* 1s */ 7621const u64 min_cfs_quota_period = 1 * NSEC_PER_MSEC; /* 1ms */ 7622 7623static int __cfs_schedulable(struct task_group *tg, u64 period, u64 runtime); 7624 7625static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota) 7626{ 7627 int i, ret = 0, runtime_enabled, runtime_was_enabled; 7628 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 7629 7630 if (tg == &root_task_group) 7631 return -EINVAL; 7632 7633 /* 7634 * Ensure we have at some amount of bandwidth every period. This is 7635 * to prevent reaching a state of large arrears when throttled via 7636 * entity_tick() resulting in prolonged exit starvation. 7637 */ 7638 if (quota < min_cfs_quota_period || period < min_cfs_quota_period) 7639 return -EINVAL; 7640 7641 /* 7642 * Likewise, bound things on the otherside by preventing insane quota 7643 * periods. This also allows us to normalize in computing quota 7644 * feasibility. 7645 */ 7646 if (period > max_cfs_quota_period) 7647 return -EINVAL; 7648 7649 mutex_lock(&cfs_constraints_mutex); 7650 ret = __cfs_schedulable(tg, period, quota); 7651 if (ret) 7652 goto out_unlock; 7653 7654 runtime_enabled = quota != RUNTIME_INF; 7655 runtime_was_enabled = cfs_b->quota != RUNTIME_INF; 7656 /* 7657 * If we need to toggle cfs_bandwidth_used, off->on must occur 7658 * before making related changes, and on->off must occur afterwards 7659 */ 7660 if (runtime_enabled && !runtime_was_enabled) 7661 cfs_bandwidth_usage_inc(); 7662 raw_spin_lock_irq(&cfs_b->lock); 7663 cfs_b->period = ns_to_ktime(period); 7664 cfs_b->quota = quota; 7665 7666 __refill_cfs_bandwidth_runtime(cfs_b); 7667 /* restart the period timer (if active) to handle new period expiry */ 7668 if (runtime_enabled && cfs_b->timer_active) { 7669 /* force a reprogram */ 7670 cfs_b->timer_active = 0; 7671 __start_cfs_bandwidth(cfs_b); 7672 } 7673 raw_spin_unlock_irq(&cfs_b->lock); 7674 7675 for_each_possible_cpu(i) { 7676 struct cfs_rq *cfs_rq = tg->cfs_rq[i]; 7677 struct rq *rq = cfs_rq->rq; 7678 7679 raw_spin_lock_irq(&rq->lock); 7680 cfs_rq->runtime_enabled = runtime_enabled; 7681 cfs_rq->runtime_remaining = 0; 7682 7683 if (cfs_rq->throttled) 7684 unthrottle_cfs_rq(cfs_rq); 7685 raw_spin_unlock_irq(&rq->lock); 7686 } 7687 if (runtime_was_enabled && !runtime_enabled) 7688 cfs_bandwidth_usage_dec(); 7689out_unlock: 7690 mutex_unlock(&cfs_constraints_mutex); 7691 7692 return ret; 7693} 7694 7695int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us) 7696{ 7697 u64 quota, period; 7698 7699 period = ktime_to_ns(tg->cfs_bandwidth.period); 7700 if (cfs_quota_us < 0) 7701 quota = RUNTIME_INF; 7702 else 7703 quota = (u64)cfs_quota_us * NSEC_PER_USEC; 7704 7705 return tg_set_cfs_bandwidth(tg, period, quota); 7706} 7707 7708long tg_get_cfs_quota(struct task_group *tg) 7709{ 7710 u64 quota_us; 7711 7712 if (tg->cfs_bandwidth.quota == RUNTIME_INF) 7713 return -1; 7714 7715 quota_us = tg->cfs_bandwidth.quota; 7716 do_div(quota_us, NSEC_PER_USEC); 7717 7718 return quota_us; 7719} 7720 7721int tg_set_cfs_period(struct task_group *tg, long cfs_period_us) 7722{ 7723 u64 quota, period; 7724 7725 period = (u64)cfs_period_us * NSEC_PER_USEC; 7726 quota = tg->cfs_bandwidth.quota; 7727 7728 return tg_set_cfs_bandwidth(tg, period, quota); 7729} 7730 7731long tg_get_cfs_period(struct task_group *tg) 7732{ 7733 u64 cfs_period_us; 7734 7735 cfs_period_us = ktime_to_ns(tg->cfs_bandwidth.period); 7736 do_div(cfs_period_us, NSEC_PER_USEC); 7737 7738 return cfs_period_us; 7739} 7740 7741static s64 cpu_cfs_quota_read_s64(struct cgroup_subsys_state *css, 7742 struct cftype *cft) 7743{ 7744 return tg_get_cfs_quota(css_tg(css)); 7745} 7746 7747static int cpu_cfs_quota_write_s64(struct cgroup_subsys_state *css, 7748 struct cftype *cftype, s64 cfs_quota_us) 7749{ 7750 return tg_set_cfs_quota(css_tg(css), cfs_quota_us); 7751} 7752 7753static u64 cpu_cfs_period_read_u64(struct cgroup_subsys_state *css, 7754 struct cftype *cft) 7755{ 7756 return tg_get_cfs_period(css_tg(css)); 7757} 7758 7759static int cpu_cfs_period_write_u64(struct cgroup_subsys_state *css, 7760 struct cftype *cftype, u64 cfs_period_us) 7761{ 7762 return tg_set_cfs_period(css_tg(css), cfs_period_us); 7763} 7764 7765struct cfs_schedulable_data { 7766 struct task_group *tg; 7767 u64 period, quota; 7768}; 7769 7770/* 7771 * normalize group quota/period to be quota/max_period 7772 * note: units are usecs 7773 */ 7774static u64 normalize_cfs_quota(struct task_group *tg, 7775 struct cfs_schedulable_data *d) 7776{ 7777 u64 quota, period; 7778 7779 if (tg == d->tg) { 7780 period = d->period; 7781 quota = d->quota; 7782 } else { 7783 period = tg_get_cfs_period(tg); 7784 quota = tg_get_cfs_quota(tg); 7785 } 7786 7787 /* note: these should typically be equivalent */ 7788 if (quota == RUNTIME_INF || quota == -1) 7789 return RUNTIME_INF; 7790 7791 return to_ratio(period, quota); 7792} 7793 7794static int tg_cfs_schedulable_down(struct task_group *tg, void *data) 7795{ 7796 struct cfs_schedulable_data *d = data; 7797 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 7798 s64 quota = 0, parent_quota = -1; 7799 7800 if (!tg->parent) { 7801 quota = RUNTIME_INF; 7802 } else { 7803 struct cfs_bandwidth *parent_b = &tg->parent->cfs_bandwidth; 7804 7805 quota = normalize_cfs_quota(tg, d); 7806 parent_quota = parent_b->hierarchal_quota; 7807 7808 /* 7809 * ensure max(child_quota) <= parent_quota, inherit when no 7810 * limit is set 7811 */ 7812 if (quota == RUNTIME_INF) 7813 quota = parent_quota; 7814 else if (parent_quota != RUNTIME_INF && quota > parent_quota) 7815 return -EINVAL; 7816 } 7817 cfs_b->hierarchal_quota = quota; 7818 7819 return 0; 7820} 7821 7822static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota) 7823{ 7824 int ret; 7825 struct cfs_schedulable_data data = { 7826 .tg = tg, 7827 .period = period, 7828 .quota = quota, 7829 }; 7830 7831 if (quota != RUNTIME_INF) { 7832 do_div(data.period, NSEC_PER_USEC); 7833 do_div(data.quota, NSEC_PER_USEC); 7834 } 7835 7836 rcu_read_lock(); 7837 ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data); 7838 rcu_read_unlock(); 7839 7840 return ret; 7841} 7842 7843static int cpu_stats_show(struct cgroup_subsys_state *css, struct cftype *cft, 7844 struct cgroup_map_cb *cb) 7845{ 7846 struct task_group *tg = css_tg(css); 7847 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 7848 7849 cb->fill(cb, "nr_periods", cfs_b->nr_periods); 7850 cb->fill(cb, "nr_throttled", cfs_b->nr_throttled); 7851 cb->fill(cb, "throttled_time", cfs_b->throttled_time); 7852 7853 return 0; 7854} 7855#endif /* CONFIG_CFS_BANDWIDTH */ 7856#endif /* CONFIG_FAIR_GROUP_SCHED */ 7857 7858#ifdef CONFIG_RT_GROUP_SCHED 7859static int cpu_rt_runtime_write(struct cgroup_subsys_state *css, 7860 struct cftype *cft, s64 val) 7861{ 7862 return sched_group_set_rt_runtime(css_tg(css), val); 7863} 7864 7865static s64 cpu_rt_runtime_read(struct cgroup_subsys_state *css, 7866 struct cftype *cft) 7867{ 7868 return sched_group_rt_runtime(css_tg(css)); 7869} 7870 7871static int cpu_rt_period_write_uint(struct cgroup_subsys_state *css, 7872 struct cftype *cftype, u64 rt_period_us) 7873{ 7874 return sched_group_set_rt_period(css_tg(css), rt_period_us); 7875} 7876 7877static u64 cpu_rt_period_read_uint(struct cgroup_subsys_state *css, 7878 struct cftype *cft) 7879{ 7880 return sched_group_rt_period(css_tg(css)); 7881} 7882#endif /* CONFIG_RT_GROUP_SCHED */ 7883 7884static struct cftype cpu_files[] = { 7885#ifdef CONFIG_FAIR_GROUP_SCHED 7886 { 7887 .name = "shares", 7888 .read_u64 = cpu_shares_read_u64, 7889 .write_u64 = cpu_shares_write_u64, 7890 }, 7891#endif 7892#ifdef CONFIG_CFS_BANDWIDTH 7893 { 7894 .name = "cfs_quota_us", 7895 .read_s64 = cpu_cfs_quota_read_s64, 7896 .write_s64 = cpu_cfs_quota_write_s64, 7897 }, 7898 { 7899 .name = "cfs_period_us", 7900 .read_u64 = cpu_cfs_period_read_u64, 7901 .write_u64 = cpu_cfs_period_write_u64, 7902 }, 7903 { 7904 .name = "stat", 7905 .read_map = cpu_stats_show, 7906 }, 7907#endif 7908#ifdef CONFIG_RT_GROUP_SCHED 7909 { 7910 .name = "rt_runtime_us", 7911 .read_s64 = cpu_rt_runtime_read, 7912 .write_s64 = cpu_rt_runtime_write, 7913 }, 7914 { 7915 .name = "rt_period_us", 7916 .read_u64 = cpu_rt_period_read_uint, 7917 .write_u64 = cpu_rt_period_write_uint, 7918 }, 7919#endif 7920 { } /* terminate */ 7921}; 7922 7923struct cgroup_subsys cpu_cgroup_subsys = { 7924 .name = "cpu", 7925 .css_alloc = cpu_cgroup_css_alloc, 7926 .css_free = cpu_cgroup_css_free, 7927 .css_online = cpu_cgroup_css_online, 7928 .css_offline = cpu_cgroup_css_offline, 7929 .can_attach = cpu_cgroup_can_attach, 7930 .attach = cpu_cgroup_attach, 7931 .exit = cpu_cgroup_exit, 7932 .subsys_id = cpu_cgroup_subsys_id, 7933 .base_cftypes = cpu_files, 7934 .early_init = 1, 7935}; 7936 7937#endif /* CONFIG_CGROUP_SCHED */ 7938 7939void dump_cpu_task(int cpu) 7940{ 7941 pr_info("Task dump for CPU %d:\n", cpu); 7942 sched_show_task(cpu_curr(cpu)); 7943} 7944