core.c revision 383afd0971538b3d77532a56404b24cfe967b5dd
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 * __task_rq_lock - lock the rq @p resides on. 301 */ 302static inline struct rq *__task_rq_lock(struct task_struct *p) 303 __acquires(rq->lock) 304{ 305 struct rq *rq; 306 307 lockdep_assert_held(&p->pi_lock); 308 309 for (;;) { 310 rq = task_rq(p); 311 raw_spin_lock(&rq->lock); 312 if (likely(rq == task_rq(p))) 313 return rq; 314 raw_spin_unlock(&rq->lock); 315 } 316} 317 318/* 319 * task_rq_lock - lock p->pi_lock and lock the rq @p resides on. 320 */ 321static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags) 322 __acquires(p->pi_lock) 323 __acquires(rq->lock) 324{ 325 struct rq *rq; 326 327 for (;;) { 328 raw_spin_lock_irqsave(&p->pi_lock, *flags); 329 rq = task_rq(p); 330 raw_spin_lock(&rq->lock); 331 if (likely(rq == task_rq(p))) 332 return rq; 333 raw_spin_unlock(&rq->lock); 334 raw_spin_unlock_irqrestore(&p->pi_lock, *flags); 335 } 336} 337 338static void __task_rq_unlock(struct rq *rq) 339 __releases(rq->lock) 340{ 341 raw_spin_unlock(&rq->lock); 342} 343 344static inline void 345task_rq_unlock(struct rq *rq, struct task_struct *p, unsigned long *flags) 346 __releases(rq->lock) 347 __releases(p->pi_lock) 348{ 349 raw_spin_unlock(&rq->lock); 350 raw_spin_unlock_irqrestore(&p->pi_lock, *flags); 351} 352 353/* 354 * this_rq_lock - lock this runqueue and disable interrupts. 355 */ 356static struct rq *this_rq_lock(void) 357 __acquires(rq->lock) 358{ 359 struct rq *rq; 360 361 local_irq_disable(); 362 rq = this_rq(); 363 raw_spin_lock(&rq->lock); 364 365 return rq; 366} 367 368#ifdef CONFIG_SCHED_HRTICK 369/* 370 * Use HR-timers to deliver accurate preemption points. 371 */ 372 373static void hrtick_clear(struct rq *rq) 374{ 375 if (hrtimer_active(&rq->hrtick_timer)) 376 hrtimer_cancel(&rq->hrtick_timer); 377} 378 379/* 380 * High-resolution timer tick. 381 * Runs from hardirq context with interrupts disabled. 382 */ 383static enum hrtimer_restart hrtick(struct hrtimer *timer) 384{ 385 struct rq *rq = container_of(timer, struct rq, hrtick_timer); 386 387 WARN_ON_ONCE(cpu_of(rq) != smp_processor_id()); 388 389 raw_spin_lock(&rq->lock); 390 update_rq_clock(rq); 391 rq->curr->sched_class->task_tick(rq, rq->curr, 1); 392 raw_spin_unlock(&rq->lock); 393 394 return HRTIMER_NORESTART; 395} 396 397#ifdef CONFIG_SMP 398 399static int __hrtick_restart(struct rq *rq) 400{ 401 struct hrtimer *timer = &rq->hrtick_timer; 402 ktime_t time = hrtimer_get_softexpires(timer); 403 404 return __hrtimer_start_range_ns(timer, time, 0, HRTIMER_MODE_ABS_PINNED, 0); 405} 406 407/* 408 * called from hardirq (IPI) context 409 */ 410static void __hrtick_start(void *arg) 411{ 412 struct rq *rq = arg; 413 414 raw_spin_lock(&rq->lock); 415 __hrtick_restart(rq); 416 rq->hrtick_csd_pending = 0; 417 raw_spin_unlock(&rq->lock); 418} 419 420/* 421 * Called to set the hrtick timer state. 422 * 423 * called with rq->lock held and irqs disabled 424 */ 425void hrtick_start(struct rq *rq, u64 delay) 426{ 427 struct hrtimer *timer = &rq->hrtick_timer; 428 ktime_t time = ktime_add_ns(timer->base->get_time(), delay); 429 430 hrtimer_set_expires(timer, time); 431 432 if (rq == this_rq()) { 433 __hrtick_restart(rq); 434 } else if (!rq->hrtick_csd_pending) { 435 __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd, 0); 436 rq->hrtick_csd_pending = 1; 437 } 438} 439 440static int 441hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu) 442{ 443 int cpu = (int)(long)hcpu; 444 445 switch (action) { 446 case CPU_UP_CANCELED: 447 case CPU_UP_CANCELED_FROZEN: 448 case CPU_DOWN_PREPARE: 449 case CPU_DOWN_PREPARE_FROZEN: 450 case CPU_DEAD: 451 case CPU_DEAD_FROZEN: 452 hrtick_clear(cpu_rq(cpu)); 453 return NOTIFY_OK; 454 } 455 456 return NOTIFY_DONE; 457} 458 459static __init void init_hrtick(void) 460{ 461 hotcpu_notifier(hotplug_hrtick, 0); 462} 463#else 464/* 465 * Called to set the hrtick timer state. 466 * 467 * called with rq->lock held and irqs disabled 468 */ 469void hrtick_start(struct rq *rq, u64 delay) 470{ 471 __hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0, 472 HRTIMER_MODE_REL_PINNED, 0); 473} 474 475static inline void init_hrtick(void) 476{ 477} 478#endif /* CONFIG_SMP */ 479 480static void init_rq_hrtick(struct rq *rq) 481{ 482#ifdef CONFIG_SMP 483 rq->hrtick_csd_pending = 0; 484 485 rq->hrtick_csd.flags = 0; 486 rq->hrtick_csd.func = __hrtick_start; 487 rq->hrtick_csd.info = rq; 488#endif 489 490 hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 491 rq->hrtick_timer.function = hrtick; 492} 493#else /* CONFIG_SCHED_HRTICK */ 494static inline void hrtick_clear(struct rq *rq) 495{ 496} 497 498static inline void init_rq_hrtick(struct rq *rq) 499{ 500} 501 502static inline void init_hrtick(void) 503{ 504} 505#endif /* CONFIG_SCHED_HRTICK */ 506 507/* 508 * resched_task - mark a task 'to be rescheduled now'. 509 * 510 * On UP this means the setting of the need_resched flag, on SMP it 511 * might also involve a cross-CPU call to trigger the scheduler on 512 * the target CPU. 513 */ 514void resched_task(struct task_struct *p) 515{ 516 int cpu; 517 518 lockdep_assert_held(&task_rq(p)->lock); 519 520 if (test_tsk_need_resched(p)) 521 return; 522 523 set_tsk_need_resched(p); 524 525 cpu = task_cpu(p); 526 if (cpu == smp_processor_id()) { 527 set_preempt_need_resched(); 528 return; 529 } 530 531 /* NEED_RESCHED must be visible before we test polling */ 532 smp_mb(); 533 if (!tsk_is_polling(p)) 534 smp_send_reschedule(cpu); 535} 536 537void resched_cpu(int cpu) 538{ 539 struct rq *rq = cpu_rq(cpu); 540 unsigned long flags; 541 542 if (!raw_spin_trylock_irqsave(&rq->lock, flags)) 543 return; 544 resched_task(cpu_curr(cpu)); 545 raw_spin_unlock_irqrestore(&rq->lock, flags); 546} 547 548#ifdef CONFIG_SMP 549#ifdef CONFIG_NO_HZ_COMMON 550/* 551 * In the semi idle case, use the nearest busy cpu for migrating timers 552 * from an idle cpu. This is good for power-savings. 553 * 554 * We don't do similar optimization for completely idle system, as 555 * selecting an idle cpu will add more delays to the timers than intended 556 * (as that cpu's timer base may not be uptodate wrt jiffies etc). 557 */ 558int get_nohz_timer_target(void) 559{ 560 int cpu = smp_processor_id(); 561 int i; 562 struct sched_domain *sd; 563 564 rcu_read_lock(); 565 for_each_domain(cpu, sd) { 566 for_each_cpu(i, sched_domain_span(sd)) { 567 if (!idle_cpu(i)) { 568 cpu = i; 569 goto unlock; 570 } 571 } 572 } 573unlock: 574 rcu_read_unlock(); 575 return cpu; 576} 577/* 578 * When add_timer_on() enqueues a timer into the timer wheel of an 579 * idle CPU then this timer might expire before the next timer event 580 * which is scheduled to wake up that CPU. In case of a completely 581 * idle system the next event might even be infinite time into the 582 * future. wake_up_idle_cpu() ensures that the CPU is woken up and 583 * leaves the inner idle loop so the newly added timer is taken into 584 * account when the CPU goes back to idle and evaluates the timer 585 * wheel for the next timer event. 586 */ 587static void wake_up_idle_cpu(int cpu) 588{ 589 struct rq *rq = cpu_rq(cpu); 590 591 if (cpu == smp_processor_id()) 592 return; 593 594 /* 595 * This is safe, as this function is called with the timer 596 * wheel base lock of (cpu) held. When the CPU is on the way 597 * to idle and has not yet set rq->curr to idle then it will 598 * be serialized on the timer wheel base lock and take the new 599 * timer into account automatically. 600 */ 601 if (rq->curr != rq->idle) 602 return; 603 604 /* 605 * We can set TIF_RESCHED on the idle task of the other CPU 606 * lockless. The worst case is that the other CPU runs the 607 * idle task through an additional NOOP schedule() 608 */ 609 set_tsk_need_resched(rq->idle); 610 611 /* NEED_RESCHED must be visible before we test polling */ 612 smp_mb(); 613 if (!tsk_is_polling(rq->idle)) 614 smp_send_reschedule(cpu); 615} 616 617static bool wake_up_full_nohz_cpu(int cpu) 618{ 619 if (tick_nohz_full_cpu(cpu)) { 620 if (cpu != smp_processor_id() || 621 tick_nohz_tick_stopped()) 622 smp_send_reschedule(cpu); 623 return true; 624 } 625 626 return false; 627} 628 629void wake_up_nohz_cpu(int cpu) 630{ 631 if (!wake_up_full_nohz_cpu(cpu)) 632 wake_up_idle_cpu(cpu); 633} 634 635static inline bool got_nohz_idle_kick(void) 636{ 637 int cpu = smp_processor_id(); 638 639 if (!test_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu))) 640 return false; 641 642 if (idle_cpu(cpu) && !need_resched()) 643 return true; 644 645 /* 646 * We can't run Idle Load Balance on this CPU for this time so we 647 * cancel it and clear NOHZ_BALANCE_KICK 648 */ 649 clear_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu)); 650 return false; 651} 652 653#else /* CONFIG_NO_HZ_COMMON */ 654 655static inline bool got_nohz_idle_kick(void) 656{ 657 return false; 658} 659 660#endif /* CONFIG_NO_HZ_COMMON */ 661 662#ifdef CONFIG_NO_HZ_FULL 663bool sched_can_stop_tick(void) 664{ 665 struct rq *rq; 666 667 rq = this_rq(); 668 669 /* Make sure rq->nr_running update is visible after the IPI */ 670 smp_rmb(); 671 672 /* More than one running task need preemption */ 673 if (rq->nr_running > 1) 674 return false; 675 676 return true; 677} 678#endif /* CONFIG_NO_HZ_FULL */ 679 680void sched_avg_update(struct rq *rq) 681{ 682 s64 period = sched_avg_period(); 683 684 while ((s64)(rq_clock(rq) - rq->age_stamp) > period) { 685 /* 686 * Inline assembly required to prevent the compiler 687 * optimising this loop into a divmod call. 688 * See __iter_div_u64_rem() for another example of this. 689 */ 690 asm("" : "+rm" (rq->age_stamp)); 691 rq->age_stamp += period; 692 rq->rt_avg /= 2; 693 } 694} 695 696#endif /* CONFIG_SMP */ 697 698#if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \ 699 (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH))) 700/* 701 * Iterate task_group tree rooted at *from, calling @down when first entering a 702 * node and @up when leaving it for the final time. 703 * 704 * Caller must hold rcu_lock or sufficient equivalent. 705 */ 706int walk_tg_tree_from(struct task_group *from, 707 tg_visitor down, tg_visitor up, void *data) 708{ 709 struct task_group *parent, *child; 710 int ret; 711 712 parent = from; 713 714down: 715 ret = (*down)(parent, data); 716 if (ret) 717 goto out; 718 list_for_each_entry_rcu(child, &parent->children, siblings) { 719 parent = child; 720 goto down; 721 722up: 723 continue; 724 } 725 ret = (*up)(parent, data); 726 if (ret || parent == from) 727 goto out; 728 729 child = parent; 730 parent = parent->parent; 731 if (parent) 732 goto up; 733out: 734 return ret; 735} 736 737int tg_nop(struct task_group *tg, void *data) 738{ 739 return 0; 740} 741#endif 742 743static void set_load_weight(struct task_struct *p) 744{ 745 int prio = p->static_prio - MAX_RT_PRIO; 746 struct load_weight *load = &p->se.load; 747 748 /* 749 * SCHED_IDLE tasks get minimal weight: 750 */ 751 if (p->policy == SCHED_IDLE) { 752 load->weight = scale_load(WEIGHT_IDLEPRIO); 753 load->inv_weight = WMULT_IDLEPRIO; 754 return; 755 } 756 757 load->weight = scale_load(prio_to_weight[prio]); 758 load->inv_weight = prio_to_wmult[prio]; 759} 760 761static void enqueue_task(struct rq *rq, struct task_struct *p, int flags) 762{ 763 update_rq_clock(rq); 764 sched_info_queued(rq, p); 765 p->sched_class->enqueue_task(rq, p, flags); 766} 767 768static void dequeue_task(struct rq *rq, struct task_struct *p, int flags) 769{ 770 update_rq_clock(rq); 771 sched_info_dequeued(rq, p); 772 p->sched_class->dequeue_task(rq, p, flags); 773} 774 775void activate_task(struct rq *rq, struct task_struct *p, int flags) 776{ 777 if (task_contributes_to_load(p)) 778 rq->nr_uninterruptible--; 779 780 enqueue_task(rq, p, flags); 781} 782 783void deactivate_task(struct rq *rq, struct task_struct *p, int flags) 784{ 785 if (task_contributes_to_load(p)) 786 rq->nr_uninterruptible++; 787 788 dequeue_task(rq, p, flags); 789} 790 791static void update_rq_clock_task(struct rq *rq, s64 delta) 792{ 793/* 794 * In theory, the compile should just see 0 here, and optimize out the call 795 * to sched_rt_avg_update. But I don't trust it... 796 */ 797#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) 798 s64 steal = 0, irq_delta = 0; 799#endif 800#ifdef CONFIG_IRQ_TIME_ACCOUNTING 801 irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time; 802 803 /* 804 * Since irq_time is only updated on {soft,}irq_exit, we might run into 805 * this case when a previous update_rq_clock() happened inside a 806 * {soft,}irq region. 807 * 808 * When this happens, we stop ->clock_task and only update the 809 * prev_irq_time stamp to account for the part that fit, so that a next 810 * update will consume the rest. This ensures ->clock_task is 811 * monotonic. 812 * 813 * It does however cause some slight miss-attribution of {soft,}irq 814 * time, a more accurate solution would be to update the irq_time using 815 * the current rq->clock timestamp, except that would require using 816 * atomic ops. 817 */ 818 if (irq_delta > delta) 819 irq_delta = delta; 820 821 rq->prev_irq_time += irq_delta; 822 delta -= irq_delta; 823#endif 824#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING 825 if (static_key_false((¶virt_steal_rq_enabled))) { 826 u64 st; 827 828 steal = paravirt_steal_clock(cpu_of(rq)); 829 steal -= rq->prev_steal_time_rq; 830 831 if (unlikely(steal > delta)) 832 steal = delta; 833 834 st = steal_ticks(steal); 835 steal = st * TICK_NSEC; 836 837 rq->prev_steal_time_rq += steal; 838 839 delta -= steal; 840 } 841#endif 842 843 rq->clock_task += delta; 844 845#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) 846 if ((irq_delta + steal) && sched_feat(NONTASK_POWER)) 847 sched_rt_avg_update(rq, irq_delta + steal); 848#endif 849} 850 851void sched_set_stop_task(int cpu, struct task_struct *stop) 852{ 853 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 }; 854 struct task_struct *old_stop = cpu_rq(cpu)->stop; 855 856 if (stop) { 857 /* 858 * Make it appear like a SCHED_FIFO task, its something 859 * userspace knows about and won't get confused about. 860 * 861 * Also, it will make PI more or less work without too 862 * much confusion -- but then, stop work should not 863 * rely on PI working anyway. 864 */ 865 sched_setscheduler_nocheck(stop, SCHED_FIFO, ¶m); 866 867 stop->sched_class = &stop_sched_class; 868 } 869 870 cpu_rq(cpu)->stop = stop; 871 872 if (old_stop) { 873 /* 874 * Reset it back to a normal scheduling class so that 875 * it can die in pieces. 876 */ 877 old_stop->sched_class = &rt_sched_class; 878 } 879} 880 881/* 882 * __normal_prio - return the priority that is based on the static prio 883 */ 884static inline int __normal_prio(struct task_struct *p) 885{ 886 return p->static_prio; 887} 888 889/* 890 * Calculate the expected normal priority: i.e. priority 891 * without taking RT-inheritance into account. Might be 892 * boosted by interactivity modifiers. Changes upon fork, 893 * setprio syscalls, and whenever the interactivity 894 * estimator recalculates. 895 */ 896static inline int normal_prio(struct task_struct *p) 897{ 898 int prio; 899 900 if (task_has_dl_policy(p)) 901 prio = MAX_DL_PRIO-1; 902 else if (task_has_rt_policy(p)) 903 prio = MAX_RT_PRIO-1 - p->rt_priority; 904 else 905 prio = __normal_prio(p); 906 return prio; 907} 908 909/* 910 * Calculate the current priority, i.e. the priority 911 * taken into account by the scheduler. This value might 912 * be boosted by RT tasks, or might be boosted by 913 * interactivity modifiers. Will be RT if the task got 914 * RT-boosted. If not then it returns p->normal_prio. 915 */ 916static int effective_prio(struct task_struct *p) 917{ 918 p->normal_prio = normal_prio(p); 919 /* 920 * If we are RT tasks or we were boosted to RT priority, 921 * keep the priority unchanged. Otherwise, update priority 922 * to the normal priority: 923 */ 924 if (!rt_prio(p->prio)) 925 return p->normal_prio; 926 return p->prio; 927} 928 929/** 930 * task_curr - is this task currently executing on a CPU? 931 * @p: the task in question. 932 * 933 * Return: 1 if the task is currently executing. 0 otherwise. 934 */ 935inline int task_curr(const struct task_struct *p) 936{ 937 return cpu_curr(task_cpu(p)) == p; 938} 939 940static inline void check_class_changed(struct rq *rq, struct task_struct *p, 941 const struct sched_class *prev_class, 942 int oldprio) 943{ 944 if (prev_class != p->sched_class) { 945 if (prev_class->switched_from) 946 prev_class->switched_from(rq, p); 947 p->sched_class->switched_to(rq, p); 948 } else if (oldprio != p->prio || dl_task(p)) 949 p->sched_class->prio_changed(rq, p, oldprio); 950} 951 952void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags) 953{ 954 const struct sched_class *class; 955 956 if (p->sched_class == rq->curr->sched_class) { 957 rq->curr->sched_class->check_preempt_curr(rq, p, flags); 958 } else { 959 for_each_class(class) { 960 if (class == rq->curr->sched_class) 961 break; 962 if (class == p->sched_class) { 963 resched_task(rq->curr); 964 break; 965 } 966 } 967 } 968 969 /* 970 * A queue event has occurred, and we're going to schedule. In 971 * this case, we can save a useless back to back clock update. 972 */ 973 if (rq->curr->on_rq && test_tsk_need_resched(rq->curr)) 974 rq->skip_clock_update = 1; 975} 976 977#ifdef CONFIG_SMP 978void set_task_cpu(struct task_struct *p, unsigned int new_cpu) 979{ 980#ifdef CONFIG_SCHED_DEBUG 981 /* 982 * We should never call set_task_cpu() on a blocked task, 983 * ttwu() will sort out the placement. 984 */ 985 WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING && 986 !(task_preempt_count(p) & PREEMPT_ACTIVE)); 987 988#ifdef CONFIG_LOCKDEP 989 /* 990 * The caller should hold either p->pi_lock or rq->lock, when changing 991 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks. 992 * 993 * sched_move_task() holds both and thus holding either pins the cgroup, 994 * see task_group(). 995 * 996 * Furthermore, all task_rq users should acquire both locks, see 997 * task_rq_lock(). 998 */ 999 WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) || 1000 lockdep_is_held(&task_rq(p)->lock))); 1001#endif 1002#endif 1003 1004 trace_sched_migrate_task(p, new_cpu); 1005 1006 if (task_cpu(p) != new_cpu) { 1007 if (p->sched_class->migrate_task_rq) 1008 p->sched_class->migrate_task_rq(p, new_cpu); 1009 p->se.nr_migrations++; 1010 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, 1, NULL, 0); 1011 } 1012 1013 __set_task_cpu(p, new_cpu); 1014} 1015 1016static void __migrate_swap_task(struct task_struct *p, int cpu) 1017{ 1018 if (p->on_rq) { 1019 struct rq *src_rq, *dst_rq; 1020 1021 src_rq = task_rq(p); 1022 dst_rq = cpu_rq(cpu); 1023 1024 deactivate_task(src_rq, p, 0); 1025 set_task_cpu(p, cpu); 1026 activate_task(dst_rq, p, 0); 1027 check_preempt_curr(dst_rq, p, 0); 1028 } else { 1029 /* 1030 * Task isn't running anymore; make it appear like we migrated 1031 * it before it went to sleep. This means on wakeup we make the 1032 * previous cpu our targer instead of where it really is. 1033 */ 1034 p->wake_cpu = cpu; 1035 } 1036} 1037 1038struct migration_swap_arg { 1039 struct task_struct *src_task, *dst_task; 1040 int src_cpu, dst_cpu; 1041}; 1042 1043static int migrate_swap_stop(void *data) 1044{ 1045 struct migration_swap_arg *arg = data; 1046 struct rq *src_rq, *dst_rq; 1047 int ret = -EAGAIN; 1048 1049 src_rq = cpu_rq(arg->src_cpu); 1050 dst_rq = cpu_rq(arg->dst_cpu); 1051 1052 double_raw_lock(&arg->src_task->pi_lock, 1053 &arg->dst_task->pi_lock); 1054 double_rq_lock(src_rq, dst_rq); 1055 if (task_cpu(arg->dst_task) != arg->dst_cpu) 1056 goto unlock; 1057 1058 if (task_cpu(arg->src_task) != arg->src_cpu) 1059 goto unlock; 1060 1061 if (!cpumask_test_cpu(arg->dst_cpu, tsk_cpus_allowed(arg->src_task))) 1062 goto unlock; 1063 1064 if (!cpumask_test_cpu(arg->src_cpu, tsk_cpus_allowed(arg->dst_task))) 1065 goto unlock; 1066 1067 __migrate_swap_task(arg->src_task, arg->dst_cpu); 1068 __migrate_swap_task(arg->dst_task, arg->src_cpu); 1069 1070 ret = 0; 1071 1072unlock: 1073 double_rq_unlock(src_rq, dst_rq); 1074 raw_spin_unlock(&arg->dst_task->pi_lock); 1075 raw_spin_unlock(&arg->src_task->pi_lock); 1076 1077 return ret; 1078} 1079 1080/* 1081 * Cross migrate two tasks 1082 */ 1083int migrate_swap(struct task_struct *cur, struct task_struct *p) 1084{ 1085 struct migration_swap_arg arg; 1086 int ret = -EINVAL; 1087 1088 arg = (struct migration_swap_arg){ 1089 .src_task = cur, 1090 .src_cpu = task_cpu(cur), 1091 .dst_task = p, 1092 .dst_cpu = task_cpu(p), 1093 }; 1094 1095 if (arg.src_cpu == arg.dst_cpu) 1096 goto out; 1097 1098 /* 1099 * These three tests are all lockless; this is OK since all of them 1100 * will be re-checked with proper locks held further down the line. 1101 */ 1102 if (!cpu_active(arg.src_cpu) || !cpu_active(arg.dst_cpu)) 1103 goto out; 1104 1105 if (!cpumask_test_cpu(arg.dst_cpu, tsk_cpus_allowed(arg.src_task))) 1106 goto out; 1107 1108 if (!cpumask_test_cpu(arg.src_cpu, tsk_cpus_allowed(arg.dst_task))) 1109 goto out; 1110 1111 trace_sched_swap_numa(cur, arg.src_cpu, p, arg.dst_cpu); 1112 ret = stop_two_cpus(arg.dst_cpu, arg.src_cpu, migrate_swap_stop, &arg); 1113 1114out: 1115 return ret; 1116} 1117 1118struct migration_arg { 1119 struct task_struct *task; 1120 int dest_cpu; 1121}; 1122 1123static int migration_cpu_stop(void *data); 1124 1125/* 1126 * wait_task_inactive - wait for a thread to unschedule. 1127 * 1128 * If @match_state is nonzero, it's the @p->state value just checked and 1129 * not expected to change. If it changes, i.e. @p might have woken up, 1130 * then return zero. When we succeed in waiting for @p to be off its CPU, 1131 * we return a positive number (its total switch count). If a second call 1132 * a short while later returns the same number, the caller can be sure that 1133 * @p has remained unscheduled the whole time. 1134 * 1135 * The caller must ensure that the task *will* unschedule sometime soon, 1136 * else this function might spin for a *long* time. This function can't 1137 * be called with interrupts off, or it may introduce deadlock with 1138 * smp_call_function() if an IPI is sent by the same process we are 1139 * waiting to become inactive. 1140 */ 1141unsigned long wait_task_inactive(struct task_struct *p, long match_state) 1142{ 1143 unsigned long flags; 1144 int running, on_rq; 1145 unsigned long ncsw; 1146 struct rq *rq; 1147 1148 for (;;) { 1149 /* 1150 * We do the initial early heuristics without holding 1151 * any task-queue locks at all. We'll only try to get 1152 * the runqueue lock when things look like they will 1153 * work out! 1154 */ 1155 rq = task_rq(p); 1156 1157 /* 1158 * If the task is actively running on another CPU 1159 * still, just relax and busy-wait without holding 1160 * any locks. 1161 * 1162 * NOTE! Since we don't hold any locks, it's not 1163 * even sure that "rq" stays as the right runqueue! 1164 * But we don't care, since "task_running()" will 1165 * return false if the runqueue has changed and p 1166 * is actually now running somewhere else! 1167 */ 1168 while (task_running(rq, p)) { 1169 if (match_state && unlikely(p->state != match_state)) 1170 return 0; 1171 cpu_relax(); 1172 } 1173 1174 /* 1175 * Ok, time to look more closely! We need the rq 1176 * lock now, to be *sure*. If we're wrong, we'll 1177 * just go back and repeat. 1178 */ 1179 rq = task_rq_lock(p, &flags); 1180 trace_sched_wait_task(p); 1181 running = task_running(rq, p); 1182 on_rq = p->on_rq; 1183 ncsw = 0; 1184 if (!match_state || p->state == match_state) 1185 ncsw = p->nvcsw | LONG_MIN; /* sets MSB */ 1186 task_rq_unlock(rq, p, &flags); 1187 1188 /* 1189 * If it changed from the expected state, bail out now. 1190 */ 1191 if (unlikely(!ncsw)) 1192 break; 1193 1194 /* 1195 * Was it really running after all now that we 1196 * checked with the proper locks actually held? 1197 * 1198 * Oops. Go back and try again.. 1199 */ 1200 if (unlikely(running)) { 1201 cpu_relax(); 1202 continue; 1203 } 1204 1205 /* 1206 * It's not enough that it's not actively running, 1207 * it must be off the runqueue _entirely_, and not 1208 * preempted! 1209 * 1210 * So if it was still runnable (but just not actively 1211 * running right now), it's preempted, and we should 1212 * yield - it could be a while. 1213 */ 1214 if (unlikely(on_rq)) { 1215 ktime_t to = ktime_set(0, NSEC_PER_SEC/HZ); 1216 1217 set_current_state(TASK_UNINTERRUPTIBLE); 1218 schedule_hrtimeout(&to, HRTIMER_MODE_REL); 1219 continue; 1220 } 1221 1222 /* 1223 * Ahh, all good. It wasn't running, and it wasn't 1224 * runnable, which means that it will never become 1225 * running in the future either. We're all done! 1226 */ 1227 break; 1228 } 1229 1230 return ncsw; 1231} 1232 1233/*** 1234 * kick_process - kick a running thread to enter/exit the kernel 1235 * @p: the to-be-kicked thread 1236 * 1237 * Cause a process which is running on another CPU to enter 1238 * kernel-mode, without any delay. (to get signals handled.) 1239 * 1240 * NOTE: this function doesn't have to take the runqueue lock, 1241 * because all it wants to ensure is that the remote task enters 1242 * the kernel. If the IPI races and the task has been migrated 1243 * to another CPU then no harm is done and the purpose has been 1244 * achieved as well. 1245 */ 1246void kick_process(struct task_struct *p) 1247{ 1248 int cpu; 1249 1250 preempt_disable(); 1251 cpu = task_cpu(p); 1252 if ((cpu != smp_processor_id()) && task_curr(p)) 1253 smp_send_reschedule(cpu); 1254 preempt_enable(); 1255} 1256EXPORT_SYMBOL_GPL(kick_process); 1257#endif /* CONFIG_SMP */ 1258 1259#ifdef CONFIG_SMP 1260/* 1261 * ->cpus_allowed is protected by both rq->lock and p->pi_lock 1262 */ 1263static int select_fallback_rq(int cpu, struct task_struct *p) 1264{ 1265 int nid = cpu_to_node(cpu); 1266 const struct cpumask *nodemask = NULL; 1267 enum { cpuset, possible, fail } state = cpuset; 1268 int dest_cpu; 1269 1270 /* 1271 * If the node that the cpu is on has been offlined, cpu_to_node() 1272 * will return -1. There is no cpu on the node, and we should 1273 * select the cpu on the other node. 1274 */ 1275 if (nid != -1) { 1276 nodemask = cpumask_of_node(nid); 1277 1278 /* Look for allowed, online CPU in same node. */ 1279 for_each_cpu(dest_cpu, nodemask) { 1280 if (!cpu_online(dest_cpu)) 1281 continue; 1282 if (!cpu_active(dest_cpu)) 1283 continue; 1284 if (cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) 1285 return dest_cpu; 1286 } 1287 } 1288 1289 for (;;) { 1290 /* Any allowed, online CPU? */ 1291 for_each_cpu(dest_cpu, tsk_cpus_allowed(p)) { 1292 if (!cpu_online(dest_cpu)) 1293 continue; 1294 if (!cpu_active(dest_cpu)) 1295 continue; 1296 goto out; 1297 } 1298 1299 switch (state) { 1300 case cpuset: 1301 /* No more Mr. Nice Guy. */ 1302 cpuset_cpus_allowed_fallback(p); 1303 state = possible; 1304 break; 1305 1306 case possible: 1307 do_set_cpus_allowed(p, cpu_possible_mask); 1308 state = fail; 1309 break; 1310 1311 case fail: 1312 BUG(); 1313 break; 1314 } 1315 } 1316 1317out: 1318 if (state != cpuset) { 1319 /* 1320 * Don't tell them about moving exiting tasks or 1321 * kernel threads (both mm NULL), since they never 1322 * leave kernel. 1323 */ 1324 if (p->mm && printk_ratelimit()) { 1325 printk_sched("process %d (%s) no longer affine to cpu%d\n", 1326 task_pid_nr(p), p->comm, cpu); 1327 } 1328 } 1329 1330 return dest_cpu; 1331} 1332 1333/* 1334 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable. 1335 */ 1336static inline 1337int select_task_rq(struct task_struct *p, int cpu, int sd_flags, int wake_flags) 1338{ 1339 cpu = p->sched_class->select_task_rq(p, cpu, sd_flags, wake_flags); 1340 1341 /* 1342 * In order not to call set_task_cpu() on a blocking task we need 1343 * to rely on ttwu() to place the task on a valid ->cpus_allowed 1344 * cpu. 1345 * 1346 * Since this is common to all placement strategies, this lives here. 1347 * 1348 * [ this allows ->select_task() to simply return task_cpu(p) and 1349 * not worry about this generic constraint ] 1350 */ 1351 if (unlikely(!cpumask_test_cpu(cpu, tsk_cpus_allowed(p)) || 1352 !cpu_online(cpu))) 1353 cpu = select_fallback_rq(task_cpu(p), p); 1354 1355 return cpu; 1356} 1357 1358static void update_avg(u64 *avg, u64 sample) 1359{ 1360 s64 diff = sample - *avg; 1361 *avg += diff >> 3; 1362} 1363#endif 1364 1365static void 1366ttwu_stat(struct task_struct *p, int cpu, int wake_flags) 1367{ 1368#ifdef CONFIG_SCHEDSTATS 1369 struct rq *rq = this_rq(); 1370 1371#ifdef CONFIG_SMP 1372 int this_cpu = smp_processor_id(); 1373 1374 if (cpu == this_cpu) { 1375 schedstat_inc(rq, ttwu_local); 1376 schedstat_inc(p, se.statistics.nr_wakeups_local); 1377 } else { 1378 struct sched_domain *sd; 1379 1380 schedstat_inc(p, se.statistics.nr_wakeups_remote); 1381 rcu_read_lock(); 1382 for_each_domain(this_cpu, sd) { 1383 if (cpumask_test_cpu(cpu, sched_domain_span(sd))) { 1384 schedstat_inc(sd, ttwu_wake_remote); 1385 break; 1386 } 1387 } 1388 rcu_read_unlock(); 1389 } 1390 1391 if (wake_flags & WF_MIGRATED) 1392 schedstat_inc(p, se.statistics.nr_wakeups_migrate); 1393 1394#endif /* CONFIG_SMP */ 1395 1396 schedstat_inc(rq, ttwu_count); 1397 schedstat_inc(p, se.statistics.nr_wakeups); 1398 1399 if (wake_flags & WF_SYNC) 1400 schedstat_inc(p, se.statistics.nr_wakeups_sync); 1401 1402#endif /* CONFIG_SCHEDSTATS */ 1403} 1404 1405static void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags) 1406{ 1407 activate_task(rq, p, en_flags); 1408 p->on_rq = 1; 1409 1410 /* if a worker is waking up, notify workqueue */ 1411 if (p->flags & PF_WQ_WORKER) 1412 wq_worker_waking_up(p, cpu_of(rq)); 1413} 1414 1415/* 1416 * Mark the task runnable and perform wakeup-preemption. 1417 */ 1418static void 1419ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags) 1420{ 1421 check_preempt_curr(rq, p, wake_flags); 1422 trace_sched_wakeup(p, true); 1423 1424 p->state = TASK_RUNNING; 1425#ifdef CONFIG_SMP 1426 if (p->sched_class->task_woken) 1427 p->sched_class->task_woken(rq, p); 1428 1429 if (rq->idle_stamp) { 1430 u64 delta = rq_clock(rq) - rq->idle_stamp; 1431 u64 max = 2*rq->max_idle_balance_cost; 1432 1433 update_avg(&rq->avg_idle, delta); 1434 1435 if (rq->avg_idle > max) 1436 rq->avg_idle = max; 1437 1438 rq->idle_stamp = 0; 1439 } 1440#endif 1441} 1442 1443static void 1444ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags) 1445{ 1446#ifdef CONFIG_SMP 1447 if (p->sched_contributes_to_load) 1448 rq->nr_uninterruptible--; 1449#endif 1450 1451 ttwu_activate(rq, p, ENQUEUE_WAKEUP | ENQUEUE_WAKING); 1452 ttwu_do_wakeup(rq, p, wake_flags); 1453} 1454 1455/* 1456 * Called in case the task @p isn't fully descheduled from its runqueue, 1457 * in this case we must do a remote wakeup. Its a 'light' wakeup though, 1458 * since all we need to do is flip p->state to TASK_RUNNING, since 1459 * the task is still ->on_rq. 1460 */ 1461static int ttwu_remote(struct task_struct *p, int wake_flags) 1462{ 1463 struct rq *rq; 1464 int ret = 0; 1465 1466 rq = __task_rq_lock(p); 1467 if (p->on_rq) { 1468 /* check_preempt_curr() may use rq clock */ 1469 update_rq_clock(rq); 1470 ttwu_do_wakeup(rq, p, wake_flags); 1471 ret = 1; 1472 } 1473 __task_rq_unlock(rq); 1474 1475 return ret; 1476} 1477 1478#ifdef CONFIG_SMP 1479static void sched_ttwu_pending(void) 1480{ 1481 struct rq *rq = this_rq(); 1482 struct llist_node *llist = llist_del_all(&rq->wake_list); 1483 struct task_struct *p; 1484 1485 raw_spin_lock(&rq->lock); 1486 1487 while (llist) { 1488 p = llist_entry(llist, struct task_struct, wake_entry); 1489 llist = llist_next(llist); 1490 ttwu_do_activate(rq, p, 0); 1491 } 1492 1493 raw_spin_unlock(&rq->lock); 1494} 1495 1496void scheduler_ipi(void) 1497{ 1498 /* 1499 * Fold TIF_NEED_RESCHED into the preempt_count; anybody setting 1500 * TIF_NEED_RESCHED remotely (for the first time) will also send 1501 * this IPI. 1502 */ 1503 preempt_fold_need_resched(); 1504 1505 if (llist_empty(&this_rq()->wake_list) 1506 && !tick_nohz_full_cpu(smp_processor_id()) 1507 && !got_nohz_idle_kick()) 1508 return; 1509 1510 /* 1511 * Not all reschedule IPI handlers call irq_enter/irq_exit, since 1512 * traditionally all their work was done from the interrupt return 1513 * path. Now that we actually do some work, we need to make sure 1514 * we do call them. 1515 * 1516 * Some archs already do call them, luckily irq_enter/exit nest 1517 * properly. 1518 * 1519 * Arguably we should visit all archs and update all handlers, 1520 * however a fair share of IPIs are still resched only so this would 1521 * somewhat pessimize the simple resched case. 1522 */ 1523 irq_enter(); 1524 tick_nohz_full_check(); 1525 sched_ttwu_pending(); 1526 1527 /* 1528 * Check if someone kicked us for doing the nohz idle load balance. 1529 */ 1530 if (unlikely(got_nohz_idle_kick())) { 1531 this_rq()->idle_balance = 1; 1532 raise_softirq_irqoff(SCHED_SOFTIRQ); 1533 } 1534 irq_exit(); 1535} 1536 1537static void ttwu_queue_remote(struct task_struct *p, int cpu) 1538{ 1539 if (llist_add(&p->wake_entry, &cpu_rq(cpu)->wake_list)) 1540 smp_send_reschedule(cpu); 1541} 1542 1543bool cpus_share_cache(int this_cpu, int that_cpu) 1544{ 1545 return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu); 1546} 1547#endif /* CONFIG_SMP */ 1548 1549static void ttwu_queue(struct task_struct *p, int cpu) 1550{ 1551 struct rq *rq = cpu_rq(cpu); 1552 1553#if defined(CONFIG_SMP) 1554 if (sched_feat(TTWU_QUEUE) && !cpus_share_cache(smp_processor_id(), cpu)) { 1555 sched_clock_cpu(cpu); /* sync clocks x-cpu */ 1556 ttwu_queue_remote(p, cpu); 1557 return; 1558 } 1559#endif 1560 1561 raw_spin_lock(&rq->lock); 1562 ttwu_do_activate(rq, p, 0); 1563 raw_spin_unlock(&rq->lock); 1564} 1565 1566/** 1567 * try_to_wake_up - wake up a thread 1568 * @p: the thread to be awakened 1569 * @state: the mask of task states that can be woken 1570 * @wake_flags: wake modifier flags (WF_*) 1571 * 1572 * Put it on the run-queue if it's not already there. The "current" 1573 * thread is always on the run-queue (except when the actual 1574 * re-schedule is in progress), and as such you're allowed to do 1575 * the simpler "current->state = TASK_RUNNING" to mark yourself 1576 * runnable without the overhead of this. 1577 * 1578 * Return: %true if @p was woken up, %false if it was already running. 1579 * or @state didn't match @p's state. 1580 */ 1581static int 1582try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) 1583{ 1584 unsigned long flags; 1585 int cpu, success = 0; 1586 1587 /* 1588 * If we are going to wake up a thread waiting for CONDITION we 1589 * need to ensure that CONDITION=1 done by the caller can not be 1590 * reordered with p->state check below. This pairs with mb() in 1591 * set_current_state() the waiting thread does. 1592 */ 1593 smp_mb__before_spinlock(); 1594 raw_spin_lock_irqsave(&p->pi_lock, flags); 1595 if (!(p->state & state)) 1596 goto out; 1597 1598 success = 1; /* we're going to change ->state */ 1599 cpu = task_cpu(p); 1600 1601 if (p->on_rq && ttwu_remote(p, wake_flags)) 1602 goto stat; 1603 1604#ifdef CONFIG_SMP 1605 /* 1606 * If the owning (remote) cpu is still in the middle of schedule() with 1607 * this task as prev, wait until its done referencing the task. 1608 */ 1609 while (p->on_cpu) 1610 cpu_relax(); 1611 /* 1612 * Pairs with the smp_wmb() in finish_lock_switch(). 1613 */ 1614 smp_rmb(); 1615 1616 p->sched_contributes_to_load = !!task_contributes_to_load(p); 1617 p->state = TASK_WAKING; 1618 1619 if (p->sched_class->task_waking) 1620 p->sched_class->task_waking(p); 1621 1622 cpu = select_task_rq(p, p->wake_cpu, SD_BALANCE_WAKE, wake_flags); 1623 if (task_cpu(p) != cpu) { 1624 wake_flags |= WF_MIGRATED; 1625 set_task_cpu(p, cpu); 1626 } 1627#endif /* CONFIG_SMP */ 1628 1629 ttwu_queue(p, cpu); 1630stat: 1631 ttwu_stat(p, cpu, wake_flags); 1632out: 1633 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 1634 1635 return success; 1636} 1637 1638/** 1639 * try_to_wake_up_local - try to wake up a local task with rq lock held 1640 * @p: the thread to be awakened 1641 * 1642 * Put @p on the run-queue if it's not already there. The caller must 1643 * ensure that this_rq() is locked, @p is bound to this_rq() and not 1644 * the current task. 1645 */ 1646static void try_to_wake_up_local(struct task_struct *p) 1647{ 1648 struct rq *rq = task_rq(p); 1649 1650 if (WARN_ON_ONCE(rq != this_rq()) || 1651 WARN_ON_ONCE(p == current)) 1652 return; 1653 1654 lockdep_assert_held(&rq->lock); 1655 1656 if (!raw_spin_trylock(&p->pi_lock)) { 1657 raw_spin_unlock(&rq->lock); 1658 raw_spin_lock(&p->pi_lock); 1659 raw_spin_lock(&rq->lock); 1660 } 1661 1662 if (!(p->state & TASK_NORMAL)) 1663 goto out; 1664 1665 if (!p->on_rq) 1666 ttwu_activate(rq, p, ENQUEUE_WAKEUP); 1667 1668 ttwu_do_wakeup(rq, p, 0); 1669 ttwu_stat(p, smp_processor_id(), 0); 1670out: 1671 raw_spin_unlock(&p->pi_lock); 1672} 1673 1674/** 1675 * wake_up_process - Wake up a specific process 1676 * @p: The process to be woken up. 1677 * 1678 * Attempt to wake up the nominated process and move it to the set of runnable 1679 * processes. 1680 * 1681 * Return: 1 if the process was woken up, 0 if it was already running. 1682 * 1683 * It may be assumed that this function implies a write memory barrier before 1684 * changing the task state if and only if any tasks are woken up. 1685 */ 1686int wake_up_process(struct task_struct *p) 1687{ 1688 WARN_ON(task_is_stopped_or_traced(p)); 1689 return try_to_wake_up(p, TASK_NORMAL, 0); 1690} 1691EXPORT_SYMBOL(wake_up_process); 1692 1693int wake_up_state(struct task_struct *p, unsigned int state) 1694{ 1695 return try_to_wake_up(p, state, 0); 1696} 1697 1698/* 1699 * Perform scheduler related setup for a newly forked process p. 1700 * p is forked by current. 1701 * 1702 * __sched_fork() is basic setup used by init_idle() too: 1703 */ 1704static void __sched_fork(unsigned long clone_flags, struct task_struct *p) 1705{ 1706 p->on_rq = 0; 1707 1708 p->se.on_rq = 0; 1709 p->se.exec_start = 0; 1710 p->se.sum_exec_runtime = 0; 1711 p->se.prev_sum_exec_runtime = 0; 1712 p->se.nr_migrations = 0; 1713 p->se.vruntime = 0; 1714 INIT_LIST_HEAD(&p->se.group_node); 1715 1716#ifdef CONFIG_SCHEDSTATS 1717 memset(&p->se.statistics, 0, sizeof(p->se.statistics)); 1718#endif 1719 1720 RB_CLEAR_NODE(&p->dl.rb_node); 1721 hrtimer_init(&p->dl.dl_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 1722 p->dl.dl_runtime = p->dl.runtime = 0; 1723 p->dl.dl_deadline = p->dl.deadline = 0; 1724 p->dl.dl_period = 0; 1725 p->dl.flags = 0; 1726 1727 INIT_LIST_HEAD(&p->rt.run_list); 1728 1729#ifdef CONFIG_PREEMPT_NOTIFIERS 1730 INIT_HLIST_HEAD(&p->preempt_notifiers); 1731#endif 1732 1733#ifdef CONFIG_NUMA_BALANCING 1734 if (p->mm && atomic_read(&p->mm->mm_users) == 1) { 1735 p->mm->numa_next_scan = jiffies + msecs_to_jiffies(sysctl_numa_balancing_scan_delay); 1736 p->mm->numa_scan_seq = 0; 1737 } 1738 1739 if (clone_flags & CLONE_VM) 1740 p->numa_preferred_nid = current->numa_preferred_nid; 1741 else 1742 p->numa_preferred_nid = -1; 1743 1744 p->node_stamp = 0ULL; 1745 p->numa_scan_seq = p->mm ? p->mm->numa_scan_seq : 0; 1746 p->numa_scan_period = sysctl_numa_balancing_scan_delay; 1747 p->numa_work.next = &p->numa_work; 1748 p->numa_faults_memory = NULL; 1749 p->numa_faults_buffer_memory = NULL; 1750 p->last_task_numa_placement = 0; 1751 p->last_sum_exec_runtime = 0; 1752 1753 INIT_LIST_HEAD(&p->numa_entry); 1754 p->numa_group = NULL; 1755#endif /* CONFIG_NUMA_BALANCING */ 1756} 1757 1758#ifdef CONFIG_NUMA_BALANCING 1759#ifdef CONFIG_SCHED_DEBUG 1760void set_numabalancing_state(bool enabled) 1761{ 1762 if (enabled) 1763 sched_feat_set("NUMA"); 1764 else 1765 sched_feat_set("NO_NUMA"); 1766} 1767#else 1768__read_mostly bool numabalancing_enabled; 1769 1770void set_numabalancing_state(bool enabled) 1771{ 1772 numabalancing_enabled = enabled; 1773} 1774#endif /* CONFIG_SCHED_DEBUG */ 1775 1776#ifdef CONFIG_PROC_SYSCTL 1777int sysctl_numa_balancing(struct ctl_table *table, int write, 1778 void __user *buffer, size_t *lenp, loff_t *ppos) 1779{ 1780 struct ctl_table t; 1781 int err; 1782 int state = numabalancing_enabled; 1783 1784 if (write && !capable(CAP_SYS_ADMIN)) 1785 return -EPERM; 1786 1787 t = *table; 1788 t.data = &state; 1789 err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos); 1790 if (err < 0) 1791 return err; 1792 if (write) 1793 set_numabalancing_state(state); 1794 return err; 1795} 1796#endif 1797#endif 1798 1799/* 1800 * fork()/clone()-time setup: 1801 */ 1802int sched_fork(unsigned long clone_flags, struct task_struct *p) 1803{ 1804 unsigned long flags; 1805 int cpu = get_cpu(); 1806 1807 __sched_fork(clone_flags, p); 1808 /* 1809 * We mark the process as running here. This guarantees that 1810 * nobody will actually run it, and a signal or other external 1811 * event cannot wake it up and insert it on the runqueue either. 1812 */ 1813 p->state = TASK_RUNNING; 1814 1815 /* 1816 * Make sure we do not leak PI boosting priority to the child. 1817 */ 1818 p->prio = current->normal_prio; 1819 1820 /* 1821 * Revert to default priority/policy on fork if requested. 1822 */ 1823 if (unlikely(p->sched_reset_on_fork)) { 1824 if (task_has_dl_policy(p) || task_has_rt_policy(p)) { 1825 p->policy = SCHED_NORMAL; 1826 p->static_prio = NICE_TO_PRIO(0); 1827 p->rt_priority = 0; 1828 } else if (PRIO_TO_NICE(p->static_prio) < 0) 1829 p->static_prio = NICE_TO_PRIO(0); 1830 1831 p->prio = p->normal_prio = __normal_prio(p); 1832 set_load_weight(p); 1833 1834 /* 1835 * We don't need the reset flag anymore after the fork. It has 1836 * fulfilled its duty: 1837 */ 1838 p->sched_reset_on_fork = 0; 1839 } 1840 1841 if (dl_prio(p->prio)) { 1842 put_cpu(); 1843 return -EAGAIN; 1844 } else if (rt_prio(p->prio)) { 1845 p->sched_class = &rt_sched_class; 1846 } else { 1847 p->sched_class = &fair_sched_class; 1848 } 1849 1850 if (p->sched_class->task_fork) 1851 p->sched_class->task_fork(p); 1852 1853 /* 1854 * The child is not yet in the pid-hash so no cgroup attach races, 1855 * and the cgroup is pinned to this child due to cgroup_fork() 1856 * is ran before sched_fork(). 1857 * 1858 * Silence PROVE_RCU. 1859 */ 1860 raw_spin_lock_irqsave(&p->pi_lock, flags); 1861 set_task_cpu(p, cpu); 1862 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 1863 1864#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) 1865 if (likely(sched_info_on())) 1866 memset(&p->sched_info, 0, sizeof(p->sched_info)); 1867#endif 1868#if defined(CONFIG_SMP) 1869 p->on_cpu = 0; 1870#endif 1871 init_task_preempt_count(p); 1872#ifdef CONFIG_SMP 1873 plist_node_init(&p->pushable_tasks, MAX_PRIO); 1874 RB_CLEAR_NODE(&p->pushable_dl_tasks); 1875#endif 1876 1877 put_cpu(); 1878 return 0; 1879} 1880 1881unsigned long to_ratio(u64 period, u64 runtime) 1882{ 1883 if (runtime == RUNTIME_INF) 1884 return 1ULL << 20; 1885 1886 /* 1887 * Doing this here saves a lot of checks in all 1888 * the calling paths, and returning zero seems 1889 * safe for them anyway. 1890 */ 1891 if (period == 0) 1892 return 0; 1893 1894 return div64_u64(runtime << 20, period); 1895} 1896 1897#ifdef CONFIG_SMP 1898inline struct dl_bw *dl_bw_of(int i) 1899{ 1900 return &cpu_rq(i)->rd->dl_bw; 1901} 1902 1903static inline int dl_bw_cpus(int i) 1904{ 1905 struct root_domain *rd = cpu_rq(i)->rd; 1906 int cpus = 0; 1907 1908 for_each_cpu_and(i, rd->span, cpu_active_mask) 1909 cpus++; 1910 1911 return cpus; 1912} 1913#else 1914inline struct dl_bw *dl_bw_of(int i) 1915{ 1916 return &cpu_rq(i)->dl.dl_bw; 1917} 1918 1919static inline int dl_bw_cpus(int i) 1920{ 1921 return 1; 1922} 1923#endif 1924 1925static inline 1926void __dl_clear(struct dl_bw *dl_b, u64 tsk_bw) 1927{ 1928 dl_b->total_bw -= tsk_bw; 1929} 1930 1931static inline 1932void __dl_add(struct dl_bw *dl_b, u64 tsk_bw) 1933{ 1934 dl_b->total_bw += tsk_bw; 1935} 1936 1937static inline 1938bool __dl_overflow(struct dl_bw *dl_b, int cpus, u64 old_bw, u64 new_bw) 1939{ 1940 return dl_b->bw != -1 && 1941 dl_b->bw * cpus < dl_b->total_bw - old_bw + new_bw; 1942} 1943 1944/* 1945 * We must be sure that accepting a new task (or allowing changing the 1946 * parameters of an existing one) is consistent with the bandwidth 1947 * constraints. If yes, this function also accordingly updates the currently 1948 * allocated bandwidth to reflect the new situation. 1949 * 1950 * This function is called while holding p's rq->lock. 1951 */ 1952static int dl_overflow(struct task_struct *p, int policy, 1953 const struct sched_attr *attr) 1954{ 1955 1956 struct dl_bw *dl_b = dl_bw_of(task_cpu(p)); 1957 u64 period = attr->sched_period ?: attr->sched_deadline; 1958 u64 runtime = attr->sched_runtime; 1959 u64 new_bw = dl_policy(policy) ? to_ratio(period, runtime) : 0; 1960 int cpus, err = -1; 1961 1962 if (new_bw == p->dl.dl_bw) 1963 return 0; 1964 1965 /* 1966 * Either if a task, enters, leave, or stays -deadline but changes 1967 * its parameters, we may need to update accordingly the total 1968 * allocated bandwidth of the container. 1969 */ 1970 raw_spin_lock(&dl_b->lock); 1971 cpus = dl_bw_cpus(task_cpu(p)); 1972 if (dl_policy(policy) && !task_has_dl_policy(p) && 1973 !__dl_overflow(dl_b, cpus, 0, new_bw)) { 1974 __dl_add(dl_b, new_bw); 1975 err = 0; 1976 } else if (dl_policy(policy) && task_has_dl_policy(p) && 1977 !__dl_overflow(dl_b, cpus, p->dl.dl_bw, new_bw)) { 1978 __dl_clear(dl_b, p->dl.dl_bw); 1979 __dl_add(dl_b, new_bw); 1980 err = 0; 1981 } else if (!dl_policy(policy) && task_has_dl_policy(p)) { 1982 __dl_clear(dl_b, p->dl.dl_bw); 1983 err = 0; 1984 } 1985 raw_spin_unlock(&dl_b->lock); 1986 1987 return err; 1988} 1989 1990extern void init_dl_bw(struct dl_bw *dl_b); 1991 1992/* 1993 * wake_up_new_task - wake up a newly created task for the first time. 1994 * 1995 * This function will do some initial scheduler statistics housekeeping 1996 * that must be done for every newly created context, then puts the task 1997 * on the runqueue and wakes it. 1998 */ 1999void wake_up_new_task(struct task_struct *p) 2000{ 2001 unsigned long flags; 2002 struct rq *rq; 2003 2004 raw_spin_lock_irqsave(&p->pi_lock, flags); 2005#ifdef CONFIG_SMP 2006 /* 2007 * Fork balancing, do it here and not earlier because: 2008 * - cpus_allowed can change in the fork path 2009 * - any previously selected cpu might disappear through hotplug 2010 */ 2011 set_task_cpu(p, select_task_rq(p, task_cpu(p), SD_BALANCE_FORK, 0)); 2012#endif 2013 2014 /* Initialize new task's runnable average */ 2015 init_task_runnable_average(p); 2016 rq = __task_rq_lock(p); 2017 activate_task(rq, p, 0); 2018 p->on_rq = 1; 2019 trace_sched_wakeup_new(p, true); 2020 check_preempt_curr(rq, p, WF_FORK); 2021#ifdef CONFIG_SMP 2022 if (p->sched_class->task_woken) 2023 p->sched_class->task_woken(rq, p); 2024#endif 2025 task_rq_unlock(rq, p, &flags); 2026} 2027 2028#ifdef CONFIG_PREEMPT_NOTIFIERS 2029 2030/** 2031 * preempt_notifier_register - tell me when current is being preempted & rescheduled 2032 * @notifier: notifier struct to register 2033 */ 2034void preempt_notifier_register(struct preempt_notifier *notifier) 2035{ 2036 hlist_add_head(¬ifier->link, ¤t->preempt_notifiers); 2037} 2038EXPORT_SYMBOL_GPL(preempt_notifier_register); 2039 2040/** 2041 * preempt_notifier_unregister - no longer interested in preemption notifications 2042 * @notifier: notifier struct to unregister 2043 * 2044 * This is safe to call from within a preemption notifier. 2045 */ 2046void preempt_notifier_unregister(struct preempt_notifier *notifier) 2047{ 2048 hlist_del(¬ifier->link); 2049} 2050EXPORT_SYMBOL_GPL(preempt_notifier_unregister); 2051 2052static void fire_sched_in_preempt_notifiers(struct task_struct *curr) 2053{ 2054 struct preempt_notifier *notifier; 2055 2056 hlist_for_each_entry(notifier, &curr->preempt_notifiers, link) 2057 notifier->ops->sched_in(notifier, raw_smp_processor_id()); 2058} 2059 2060static void 2061fire_sched_out_preempt_notifiers(struct task_struct *curr, 2062 struct task_struct *next) 2063{ 2064 struct preempt_notifier *notifier; 2065 2066 hlist_for_each_entry(notifier, &curr->preempt_notifiers, link) 2067 notifier->ops->sched_out(notifier, next); 2068} 2069 2070#else /* !CONFIG_PREEMPT_NOTIFIERS */ 2071 2072static void fire_sched_in_preempt_notifiers(struct task_struct *curr) 2073{ 2074} 2075 2076static void 2077fire_sched_out_preempt_notifiers(struct task_struct *curr, 2078 struct task_struct *next) 2079{ 2080} 2081 2082#endif /* CONFIG_PREEMPT_NOTIFIERS */ 2083 2084/** 2085 * prepare_task_switch - prepare to switch tasks 2086 * @rq: the runqueue preparing to switch 2087 * @prev: the current task that is being switched out 2088 * @next: the task we are going to switch to. 2089 * 2090 * This is called with the rq lock held and interrupts off. It must 2091 * be paired with a subsequent finish_task_switch after the context 2092 * switch. 2093 * 2094 * prepare_task_switch sets up locking and calls architecture specific 2095 * hooks. 2096 */ 2097static inline void 2098prepare_task_switch(struct rq *rq, struct task_struct *prev, 2099 struct task_struct *next) 2100{ 2101 trace_sched_switch(prev, next); 2102 sched_info_switch(rq, prev, next); 2103 perf_event_task_sched_out(prev, next); 2104 fire_sched_out_preempt_notifiers(prev, next); 2105 prepare_lock_switch(rq, next); 2106 prepare_arch_switch(next); 2107} 2108 2109/** 2110 * finish_task_switch - clean up after a task-switch 2111 * @rq: runqueue associated with task-switch 2112 * @prev: the thread we just switched away from. 2113 * 2114 * finish_task_switch must be called after the context switch, paired 2115 * with a prepare_task_switch call before the context switch. 2116 * finish_task_switch will reconcile locking set up by prepare_task_switch, 2117 * and do any other architecture-specific cleanup actions. 2118 * 2119 * Note that we may have delayed dropping an mm in context_switch(). If 2120 * so, we finish that here outside of the runqueue lock. (Doing it 2121 * with the lock held can cause deadlocks; see schedule() for 2122 * details.) 2123 */ 2124static void finish_task_switch(struct rq *rq, struct task_struct *prev) 2125 __releases(rq->lock) 2126{ 2127 struct mm_struct *mm = rq->prev_mm; 2128 long prev_state; 2129 2130 rq->prev_mm = NULL; 2131 2132 /* 2133 * A task struct has one reference for the use as "current". 2134 * If a task dies, then it sets TASK_DEAD in tsk->state and calls 2135 * schedule one last time. The schedule call will never return, and 2136 * the scheduled task must drop that reference. 2137 * The test for TASK_DEAD must occur while the runqueue locks are 2138 * still held, otherwise prev could be scheduled on another cpu, die 2139 * there before we look at prev->state, and then the reference would 2140 * be dropped twice. 2141 * Manfred Spraul <manfred@colorfullife.com> 2142 */ 2143 prev_state = prev->state; 2144 vtime_task_switch(prev); 2145 finish_arch_switch(prev); 2146 perf_event_task_sched_in(prev, current); 2147 finish_lock_switch(rq, prev); 2148 finish_arch_post_lock_switch(); 2149 2150 fire_sched_in_preempt_notifiers(current); 2151 if (mm) 2152 mmdrop(mm); 2153 if (unlikely(prev_state == TASK_DEAD)) { 2154 if (prev->sched_class->task_dead) 2155 prev->sched_class->task_dead(prev); 2156 2157 /* 2158 * Remove function-return probe instances associated with this 2159 * task and put them back on the free list. 2160 */ 2161 kprobe_flush_task(prev); 2162 put_task_struct(prev); 2163 } 2164 2165 tick_nohz_task_switch(current); 2166} 2167 2168#ifdef CONFIG_SMP 2169 2170/* rq->lock is NOT held, but preemption is disabled */ 2171static inline void post_schedule(struct rq *rq) 2172{ 2173 if (rq->post_schedule) { 2174 unsigned long flags; 2175 2176 raw_spin_lock_irqsave(&rq->lock, flags); 2177 if (rq->curr->sched_class->post_schedule) 2178 rq->curr->sched_class->post_schedule(rq); 2179 raw_spin_unlock_irqrestore(&rq->lock, flags); 2180 2181 rq->post_schedule = 0; 2182 } 2183} 2184 2185#else 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); 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_nsecs(next - now); 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 unsigned long ip = get_parent_ip(CALLER_ADDR1); 2504#ifdef CONFIG_DEBUG_PREEMPT 2505 current->preempt_disable_ip = ip; 2506#endif 2507 trace_preempt_off(CALLER_ADDR0, ip); 2508 } 2509} 2510EXPORT_SYMBOL(preempt_count_add); 2511 2512void __kprobes preempt_count_sub(int val) 2513{ 2514#ifdef CONFIG_DEBUG_PREEMPT 2515 /* 2516 * Underflow? 2517 */ 2518 if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) 2519 return; 2520 /* 2521 * Is the spinlock portion underflowing? 2522 */ 2523 if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && 2524 !(preempt_count() & PREEMPT_MASK))) 2525 return; 2526#endif 2527 2528 if (preempt_count() == val) 2529 trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); 2530 __preempt_count_sub(val); 2531} 2532EXPORT_SYMBOL(preempt_count_sub); 2533 2534#endif 2535 2536/* 2537 * Print scheduling while atomic bug: 2538 */ 2539static noinline void __schedule_bug(struct task_struct *prev) 2540{ 2541 if (oops_in_progress) 2542 return; 2543 2544 printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n", 2545 prev->comm, prev->pid, preempt_count()); 2546 2547 debug_show_held_locks(prev); 2548 print_modules(); 2549 if (irqs_disabled()) 2550 print_irqtrace_events(prev); 2551#ifdef CONFIG_DEBUG_PREEMPT 2552 if (in_atomic_preempt_off()) { 2553 pr_err("Preemption disabled at:"); 2554 print_ip_sym(current->preempt_disable_ip); 2555 pr_cont("\n"); 2556 } 2557#endif 2558 dump_stack(); 2559 add_taint(TAINT_WARN, LOCKDEP_STILL_OK); 2560} 2561 2562/* 2563 * Various schedule()-time debugging checks and statistics: 2564 */ 2565static inline void schedule_debug(struct task_struct *prev) 2566{ 2567 /* 2568 * Test if we are atomic. Since do_exit() needs to call into 2569 * schedule() atomically, we ignore that path. Otherwise whine 2570 * if we are scheduling when we should not. 2571 */ 2572 if (unlikely(in_atomic_preempt_off() && prev->state != TASK_DEAD)) 2573 __schedule_bug(prev); 2574 rcu_sleep_check(); 2575 2576 profile_hit(SCHED_PROFILING, __builtin_return_address(0)); 2577 2578 schedstat_inc(this_rq(), sched_count); 2579} 2580 2581/* 2582 * Pick up the highest-prio task: 2583 */ 2584static inline struct task_struct * 2585pick_next_task(struct rq *rq, struct task_struct *prev) 2586{ 2587 const struct sched_class *class = &fair_sched_class; 2588 struct task_struct *p; 2589 2590 /* 2591 * Optimization: we know that if all tasks are in 2592 * the fair class we can call that function directly: 2593 */ 2594 if (likely(prev->sched_class == class && 2595 rq->nr_running == rq->cfs.h_nr_running)) { 2596 p = fair_sched_class.pick_next_task(rq, prev); 2597 if (likely(p && p != RETRY_TASK)) 2598 return p; 2599 } 2600 2601again: 2602 for_each_class(class) { 2603 p = class->pick_next_task(rq, prev); 2604 if (p) { 2605 if (unlikely(p == RETRY_TASK)) 2606 goto again; 2607 return p; 2608 } 2609 } 2610 2611 BUG(); /* the idle class will always have a runnable task */ 2612} 2613 2614/* 2615 * __schedule() is the main scheduler function. 2616 * 2617 * The main means of driving the scheduler and thus entering this function are: 2618 * 2619 * 1. Explicit blocking: mutex, semaphore, waitqueue, etc. 2620 * 2621 * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return 2622 * paths. For example, see arch/x86/entry_64.S. 2623 * 2624 * To drive preemption between tasks, the scheduler sets the flag in timer 2625 * interrupt handler scheduler_tick(). 2626 * 2627 * 3. Wakeups don't really cause entry into schedule(). They add a 2628 * task to the run-queue and that's it. 2629 * 2630 * Now, if the new task added to the run-queue preempts the current 2631 * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets 2632 * called on the nearest possible occasion: 2633 * 2634 * - If the kernel is preemptible (CONFIG_PREEMPT=y): 2635 * 2636 * - in syscall or exception context, at the next outmost 2637 * preempt_enable(). (this might be as soon as the wake_up()'s 2638 * spin_unlock()!) 2639 * 2640 * - in IRQ context, return from interrupt-handler to 2641 * preemptible context 2642 * 2643 * - If the kernel is not preemptible (CONFIG_PREEMPT is not set) 2644 * then at the next: 2645 * 2646 * - cond_resched() call 2647 * - explicit schedule() call 2648 * - return from syscall or exception to user-space 2649 * - return from interrupt-handler to user-space 2650 */ 2651static void __sched __schedule(void) 2652{ 2653 struct task_struct *prev, *next; 2654 unsigned long *switch_count; 2655 struct rq *rq; 2656 int cpu; 2657 2658need_resched: 2659 preempt_disable(); 2660 cpu = smp_processor_id(); 2661 rq = cpu_rq(cpu); 2662 rcu_note_context_switch(cpu); 2663 prev = rq->curr; 2664 2665 schedule_debug(prev); 2666 2667 if (sched_feat(HRTICK)) 2668 hrtick_clear(rq); 2669 2670 /* 2671 * Make sure that signal_pending_state()->signal_pending() below 2672 * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE) 2673 * done by the caller to avoid the race with signal_wake_up(). 2674 */ 2675 smp_mb__before_spinlock(); 2676 raw_spin_lock_irq(&rq->lock); 2677 2678 switch_count = &prev->nivcsw; 2679 if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { 2680 if (unlikely(signal_pending_state(prev->state, prev))) { 2681 prev->state = TASK_RUNNING; 2682 } else { 2683 deactivate_task(rq, prev, DEQUEUE_SLEEP); 2684 prev->on_rq = 0; 2685 2686 /* 2687 * If a worker went to sleep, notify and ask workqueue 2688 * whether it wants to wake up a task to maintain 2689 * concurrency. 2690 */ 2691 if (prev->flags & PF_WQ_WORKER) { 2692 struct task_struct *to_wakeup; 2693 2694 to_wakeup = wq_worker_sleeping(prev, cpu); 2695 if (to_wakeup) 2696 try_to_wake_up_local(to_wakeup); 2697 } 2698 } 2699 switch_count = &prev->nvcsw; 2700 } 2701 2702 if (prev->on_rq || rq->skip_clock_update < 0) 2703 update_rq_clock(rq); 2704 2705 next = pick_next_task(rq, prev); 2706 clear_tsk_need_resched(prev); 2707 clear_preempt_need_resched(); 2708 rq->skip_clock_update = 0; 2709 2710 if (likely(prev != next)) { 2711 rq->nr_switches++; 2712 rq->curr = next; 2713 ++*switch_count; 2714 2715 context_switch(rq, prev, next); /* unlocks the rq */ 2716 /* 2717 * The context switch have flipped the stack from under us 2718 * and restored the local variables which were saved when 2719 * this task called schedule() in the past. prev == current 2720 * is still correct, but it can be moved to another cpu/rq. 2721 */ 2722 cpu = smp_processor_id(); 2723 rq = cpu_rq(cpu); 2724 } else 2725 raw_spin_unlock_irq(&rq->lock); 2726 2727 post_schedule(rq); 2728 2729 sched_preempt_enable_no_resched(); 2730 if (need_resched()) 2731 goto need_resched; 2732} 2733 2734static inline void sched_submit_work(struct task_struct *tsk) 2735{ 2736 if (!tsk->state || tsk_is_pi_blocked(tsk)) 2737 return; 2738 /* 2739 * If we are going to sleep and we have plugged IO queued, 2740 * make sure to submit it to avoid deadlocks. 2741 */ 2742 if (blk_needs_flush_plug(tsk)) 2743 blk_schedule_flush_plug(tsk); 2744} 2745 2746asmlinkage void __sched schedule(void) 2747{ 2748 struct task_struct *tsk = current; 2749 2750 sched_submit_work(tsk); 2751 __schedule(); 2752} 2753EXPORT_SYMBOL(schedule); 2754 2755#ifdef CONFIG_CONTEXT_TRACKING 2756asmlinkage void __sched schedule_user(void) 2757{ 2758 /* 2759 * If we come here after a random call to set_need_resched(), 2760 * or we have been woken up remotely but the IPI has not yet arrived, 2761 * we haven't yet exited the RCU idle mode. Do it here manually until 2762 * we find a better solution. 2763 */ 2764 user_exit(); 2765 schedule(); 2766 user_enter(); 2767} 2768#endif 2769 2770/** 2771 * schedule_preempt_disabled - called with preemption disabled 2772 * 2773 * Returns with preemption disabled. Note: preempt_count must be 1 2774 */ 2775void __sched schedule_preempt_disabled(void) 2776{ 2777 sched_preempt_enable_no_resched(); 2778 schedule(); 2779 preempt_disable(); 2780} 2781 2782#ifdef CONFIG_PREEMPT 2783/* 2784 * this is the entry point to schedule() from in-kernel preemption 2785 * off of preempt_enable. Kernel preemptions off return from interrupt 2786 * occur there and call schedule directly. 2787 */ 2788asmlinkage void __sched notrace preempt_schedule(void) 2789{ 2790 /* 2791 * If there is a non-zero preempt_count or interrupts are disabled, 2792 * we do not want to preempt the current task. Just return.. 2793 */ 2794 if (likely(!preemptible())) 2795 return; 2796 2797 do { 2798 __preempt_count_add(PREEMPT_ACTIVE); 2799 __schedule(); 2800 __preempt_count_sub(PREEMPT_ACTIVE); 2801 2802 /* 2803 * Check again in case we missed a preemption opportunity 2804 * between schedule and now. 2805 */ 2806 barrier(); 2807 } while (need_resched()); 2808} 2809EXPORT_SYMBOL(preempt_schedule); 2810#endif /* CONFIG_PREEMPT */ 2811 2812/* 2813 * this is the entry point to schedule() from kernel preemption 2814 * off of irq context. 2815 * Note, that this is called and return with irqs disabled. This will 2816 * protect us against recursive calling from irq. 2817 */ 2818asmlinkage void __sched preempt_schedule_irq(void) 2819{ 2820 enum ctx_state prev_state; 2821 2822 /* Catch callers which need to be fixed */ 2823 BUG_ON(preempt_count() || !irqs_disabled()); 2824 2825 prev_state = exception_enter(); 2826 2827 do { 2828 __preempt_count_add(PREEMPT_ACTIVE); 2829 local_irq_enable(); 2830 __schedule(); 2831 local_irq_disable(); 2832 __preempt_count_sub(PREEMPT_ACTIVE); 2833 2834 /* 2835 * Check again in case we missed a preemption opportunity 2836 * between schedule and now. 2837 */ 2838 barrier(); 2839 } while (need_resched()); 2840 2841 exception_exit(prev_state); 2842} 2843 2844int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags, 2845 void *key) 2846{ 2847 return try_to_wake_up(curr->private, mode, wake_flags); 2848} 2849EXPORT_SYMBOL(default_wake_function); 2850 2851static long __sched 2852sleep_on_common(wait_queue_head_t *q, int state, long timeout) 2853{ 2854 unsigned long flags; 2855 wait_queue_t wait; 2856 2857 init_waitqueue_entry(&wait, current); 2858 2859 __set_current_state(state); 2860 2861 spin_lock_irqsave(&q->lock, flags); 2862 __add_wait_queue(q, &wait); 2863 spin_unlock(&q->lock); 2864 timeout = schedule_timeout(timeout); 2865 spin_lock_irq(&q->lock); 2866 __remove_wait_queue(q, &wait); 2867 spin_unlock_irqrestore(&q->lock, flags); 2868 2869 return timeout; 2870} 2871 2872void __sched interruptible_sleep_on(wait_queue_head_t *q) 2873{ 2874 sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); 2875} 2876EXPORT_SYMBOL(interruptible_sleep_on); 2877 2878long __sched 2879interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout) 2880{ 2881 return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout); 2882} 2883EXPORT_SYMBOL(interruptible_sleep_on_timeout); 2884 2885void __sched sleep_on(wait_queue_head_t *q) 2886{ 2887 sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); 2888} 2889EXPORT_SYMBOL(sleep_on); 2890 2891long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout) 2892{ 2893 return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout); 2894} 2895EXPORT_SYMBOL(sleep_on_timeout); 2896 2897#ifdef CONFIG_RT_MUTEXES 2898 2899/* 2900 * rt_mutex_setprio - set the current priority of a task 2901 * @p: task 2902 * @prio: prio value (kernel-internal form) 2903 * 2904 * This function changes the 'effective' priority of a task. It does 2905 * not touch ->normal_prio like __setscheduler(). 2906 * 2907 * Used by the rt_mutex code to implement priority inheritance 2908 * logic. Call site only calls if the priority of the task changed. 2909 */ 2910void rt_mutex_setprio(struct task_struct *p, int prio) 2911{ 2912 int oldprio, on_rq, running, enqueue_flag = 0; 2913 struct rq *rq; 2914 const struct sched_class *prev_class; 2915 2916 BUG_ON(prio > MAX_PRIO); 2917 2918 rq = __task_rq_lock(p); 2919 2920 /* 2921 * Idle task boosting is a nono in general. There is one 2922 * exception, when PREEMPT_RT and NOHZ is active: 2923 * 2924 * The idle task calls get_next_timer_interrupt() and holds 2925 * the timer wheel base->lock on the CPU and another CPU wants 2926 * to access the timer (probably to cancel it). We can safely 2927 * ignore the boosting request, as the idle CPU runs this code 2928 * with interrupts disabled and will complete the lock 2929 * protected section without being interrupted. So there is no 2930 * real need to boost. 2931 */ 2932 if (unlikely(p == rq->idle)) { 2933 WARN_ON(p != rq->curr); 2934 WARN_ON(p->pi_blocked_on); 2935 goto out_unlock; 2936 } 2937 2938 trace_sched_pi_setprio(p, prio); 2939 p->pi_top_task = rt_mutex_get_top_task(p); 2940 oldprio = p->prio; 2941 prev_class = p->sched_class; 2942 on_rq = p->on_rq; 2943 running = task_current(rq, p); 2944 if (on_rq) 2945 dequeue_task(rq, p, 0); 2946 if (running) 2947 p->sched_class->put_prev_task(rq, p); 2948 2949 /* 2950 * Boosting condition are: 2951 * 1. -rt task is running and holds mutex A 2952 * --> -dl task blocks on mutex A 2953 * 2954 * 2. -dl task is running and holds mutex A 2955 * --> -dl task blocks on mutex A and could preempt the 2956 * running task 2957 */ 2958 if (dl_prio(prio)) { 2959 if (!dl_prio(p->normal_prio) || (p->pi_top_task && 2960 dl_entity_preempt(&p->pi_top_task->dl, &p->dl))) { 2961 p->dl.dl_boosted = 1; 2962 p->dl.dl_throttled = 0; 2963 enqueue_flag = ENQUEUE_REPLENISH; 2964 } else 2965 p->dl.dl_boosted = 0; 2966 p->sched_class = &dl_sched_class; 2967 } else if (rt_prio(prio)) { 2968 if (dl_prio(oldprio)) 2969 p->dl.dl_boosted = 0; 2970 if (oldprio < prio) 2971 enqueue_flag = ENQUEUE_HEAD; 2972 p->sched_class = &rt_sched_class; 2973 } else { 2974 if (dl_prio(oldprio)) 2975 p->dl.dl_boosted = 0; 2976 p->sched_class = &fair_sched_class; 2977 } 2978 2979 p->prio = prio; 2980 2981 if (running) 2982 p->sched_class->set_curr_task(rq); 2983 if (on_rq) 2984 enqueue_task(rq, p, enqueue_flag); 2985 2986 check_class_changed(rq, p, prev_class, oldprio); 2987out_unlock: 2988 __task_rq_unlock(rq); 2989} 2990#endif 2991 2992void set_user_nice(struct task_struct *p, long nice) 2993{ 2994 int old_prio, delta, on_rq; 2995 unsigned long flags; 2996 struct rq *rq; 2997 2998 if (task_nice(p) == nice || nice < MIN_NICE || nice > MAX_NICE) 2999 return; 3000 /* 3001 * We have to be careful, if called from sys_setpriority(), 3002 * the task might be in the middle of scheduling on another CPU. 3003 */ 3004 rq = task_rq_lock(p, &flags); 3005 /* 3006 * The RT priorities are set via sched_setscheduler(), but we still 3007 * allow the 'normal' nice value to be set - but as expected 3008 * it wont have any effect on scheduling until the task is 3009 * SCHED_DEADLINE, SCHED_FIFO or SCHED_RR: 3010 */ 3011 if (task_has_dl_policy(p) || task_has_rt_policy(p)) { 3012 p->static_prio = NICE_TO_PRIO(nice); 3013 goto out_unlock; 3014 } 3015 on_rq = p->on_rq; 3016 if (on_rq) 3017 dequeue_task(rq, p, 0); 3018 3019 p->static_prio = NICE_TO_PRIO(nice); 3020 set_load_weight(p); 3021 old_prio = p->prio; 3022 p->prio = effective_prio(p); 3023 delta = p->prio - old_prio; 3024 3025 if (on_rq) { 3026 enqueue_task(rq, p, 0); 3027 /* 3028 * If the task increased its priority or is running and 3029 * lowered its priority, then reschedule its CPU: 3030 */ 3031 if (delta < 0 || (delta > 0 && task_running(rq, p))) 3032 resched_task(rq->curr); 3033 } 3034out_unlock: 3035 task_rq_unlock(rq, p, &flags); 3036} 3037EXPORT_SYMBOL(set_user_nice); 3038 3039/* 3040 * can_nice - check if a task can reduce its nice value 3041 * @p: task 3042 * @nice: nice value 3043 */ 3044int can_nice(const struct task_struct *p, const int nice) 3045{ 3046 /* convert nice value [19,-20] to rlimit style value [1,40] */ 3047 int nice_rlim = 20 - nice; 3048 3049 return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) || 3050 capable(CAP_SYS_NICE)); 3051} 3052 3053#ifdef __ARCH_WANT_SYS_NICE 3054 3055/* 3056 * sys_nice - change the priority of the current process. 3057 * @increment: priority increment 3058 * 3059 * sys_setpriority is a more generic, but much slower function that 3060 * does similar things. 3061 */ 3062SYSCALL_DEFINE1(nice, int, increment) 3063{ 3064 long nice, retval; 3065 3066 /* 3067 * Setpriority might change our priority at the same moment. 3068 * We don't have to worry. Conceptually one call occurs first 3069 * and we have a single winner. 3070 */ 3071 if (increment < -40) 3072 increment = -40; 3073 if (increment > 40) 3074 increment = 40; 3075 3076 nice = task_nice(current) + increment; 3077 if (nice < MIN_NICE) 3078 nice = MIN_NICE; 3079 if (nice > MAX_NICE) 3080 nice = MAX_NICE; 3081 3082 if (increment < 0 && !can_nice(current, nice)) 3083 return -EPERM; 3084 3085 retval = security_task_setnice(current, nice); 3086 if (retval) 3087 return retval; 3088 3089 set_user_nice(current, nice); 3090 return 0; 3091} 3092 3093#endif 3094 3095/** 3096 * task_prio - return the priority value of a given task. 3097 * @p: the task in question. 3098 * 3099 * Return: The priority value as seen by users in /proc. 3100 * RT tasks are offset by -200. Normal tasks are centered 3101 * around 0, value goes from -16 to +15. 3102 */ 3103int task_prio(const struct task_struct *p) 3104{ 3105 return p->prio - MAX_RT_PRIO; 3106} 3107 3108/** 3109 * idle_cpu - is a given cpu idle currently? 3110 * @cpu: the processor in question. 3111 * 3112 * Return: 1 if the CPU is currently idle. 0 otherwise. 3113 */ 3114int idle_cpu(int cpu) 3115{ 3116 struct rq *rq = cpu_rq(cpu); 3117 3118 if (rq->curr != rq->idle) 3119 return 0; 3120 3121 if (rq->nr_running) 3122 return 0; 3123 3124#ifdef CONFIG_SMP 3125 if (!llist_empty(&rq->wake_list)) 3126 return 0; 3127#endif 3128 3129 return 1; 3130} 3131 3132/** 3133 * idle_task - return the idle task for a given cpu. 3134 * @cpu: the processor in question. 3135 * 3136 * Return: The idle task for the cpu @cpu. 3137 */ 3138struct task_struct *idle_task(int cpu) 3139{ 3140 return cpu_rq(cpu)->idle; 3141} 3142 3143/** 3144 * find_process_by_pid - find a process with a matching PID value. 3145 * @pid: the pid in question. 3146 * 3147 * The task of @pid, if found. %NULL otherwise. 3148 */ 3149static struct task_struct *find_process_by_pid(pid_t pid) 3150{ 3151 return pid ? find_task_by_vpid(pid) : current; 3152} 3153 3154/* 3155 * This function initializes the sched_dl_entity of a newly becoming 3156 * SCHED_DEADLINE task. 3157 * 3158 * Only the static values are considered here, the actual runtime and the 3159 * absolute deadline will be properly calculated when the task is enqueued 3160 * for the first time with its new policy. 3161 */ 3162static void 3163__setparam_dl(struct task_struct *p, const struct sched_attr *attr) 3164{ 3165 struct sched_dl_entity *dl_se = &p->dl; 3166 3167 init_dl_task_timer(dl_se); 3168 dl_se->dl_runtime = attr->sched_runtime; 3169 dl_se->dl_deadline = attr->sched_deadline; 3170 dl_se->dl_period = attr->sched_period ?: dl_se->dl_deadline; 3171 dl_se->flags = attr->sched_flags; 3172 dl_se->dl_bw = to_ratio(dl_se->dl_period, dl_se->dl_runtime); 3173 dl_se->dl_throttled = 0; 3174 dl_se->dl_new = 1; 3175} 3176 3177static void __setscheduler_params(struct task_struct *p, 3178 const struct sched_attr *attr) 3179{ 3180 int policy = attr->sched_policy; 3181 3182 if (policy == -1) /* setparam */ 3183 policy = p->policy; 3184 3185 p->policy = policy; 3186 3187 if (dl_policy(policy)) 3188 __setparam_dl(p, attr); 3189 else if (fair_policy(policy)) 3190 p->static_prio = NICE_TO_PRIO(attr->sched_nice); 3191 3192 /* 3193 * __sched_setscheduler() ensures attr->sched_priority == 0 when 3194 * !rt_policy. Always setting this ensures that things like 3195 * getparam()/getattr() don't report silly values for !rt tasks. 3196 */ 3197 p->rt_priority = attr->sched_priority; 3198 p->normal_prio = normal_prio(p); 3199 set_load_weight(p); 3200} 3201 3202/* Actually do priority change: must hold pi & rq lock. */ 3203static void __setscheduler(struct rq *rq, struct task_struct *p, 3204 const struct sched_attr *attr) 3205{ 3206 __setscheduler_params(p, attr); 3207 3208 /* 3209 * If we get here, there was no pi waiters boosting the 3210 * task. It is safe to use the normal prio. 3211 */ 3212 p->prio = normal_prio(p); 3213 3214 if (dl_prio(p->prio)) 3215 p->sched_class = &dl_sched_class; 3216 else if (rt_prio(p->prio)) 3217 p->sched_class = &rt_sched_class; 3218 else 3219 p->sched_class = &fair_sched_class; 3220} 3221 3222static void 3223__getparam_dl(struct task_struct *p, struct sched_attr *attr) 3224{ 3225 struct sched_dl_entity *dl_se = &p->dl; 3226 3227 attr->sched_priority = p->rt_priority; 3228 attr->sched_runtime = dl_se->dl_runtime; 3229 attr->sched_deadline = dl_se->dl_deadline; 3230 attr->sched_period = dl_se->dl_period; 3231 attr->sched_flags = dl_se->flags; 3232} 3233 3234/* 3235 * This function validates the new parameters of a -deadline task. 3236 * We ask for the deadline not being zero, and greater or equal 3237 * than the runtime, as well as the period of being zero or 3238 * greater than deadline. Furthermore, we have to be sure that 3239 * user parameters are above the internal resolution (1us); we 3240 * check sched_runtime only since it is always the smaller one. 3241 */ 3242static bool 3243__checkparam_dl(const struct sched_attr *attr) 3244{ 3245 return attr && attr->sched_deadline != 0 && 3246 (attr->sched_period == 0 || 3247 (s64)(attr->sched_period - attr->sched_deadline) >= 0) && 3248 (s64)(attr->sched_deadline - attr->sched_runtime ) >= 0 && 3249 attr->sched_runtime >= (2 << (DL_SCALE - 1)); 3250} 3251 3252/* 3253 * check the target process has a UID that matches the current process's 3254 */ 3255static bool check_same_owner(struct task_struct *p) 3256{ 3257 const struct cred *cred = current_cred(), *pcred; 3258 bool match; 3259 3260 rcu_read_lock(); 3261 pcred = __task_cred(p); 3262 match = (uid_eq(cred->euid, pcred->euid) || 3263 uid_eq(cred->euid, pcred->uid)); 3264 rcu_read_unlock(); 3265 return match; 3266} 3267 3268static int __sched_setscheduler(struct task_struct *p, 3269 const struct sched_attr *attr, 3270 bool user) 3271{ 3272 int newprio = dl_policy(attr->sched_policy) ? MAX_DL_PRIO - 1 : 3273 MAX_RT_PRIO - 1 - attr->sched_priority; 3274 int retval, oldprio, oldpolicy = -1, on_rq, running; 3275 int policy = attr->sched_policy; 3276 unsigned long flags; 3277 const struct sched_class *prev_class; 3278 struct rq *rq; 3279 int reset_on_fork; 3280 3281 /* may grab non-irq protected spin_locks */ 3282 BUG_ON(in_interrupt()); 3283recheck: 3284 /* double check policy once rq lock held */ 3285 if (policy < 0) { 3286 reset_on_fork = p->sched_reset_on_fork; 3287 policy = oldpolicy = p->policy; 3288 } else { 3289 reset_on_fork = !!(attr->sched_flags & SCHED_FLAG_RESET_ON_FORK); 3290 3291 if (policy != SCHED_DEADLINE && 3292 policy != SCHED_FIFO && policy != SCHED_RR && 3293 policy != SCHED_NORMAL && policy != SCHED_BATCH && 3294 policy != SCHED_IDLE) 3295 return -EINVAL; 3296 } 3297 3298 if (attr->sched_flags & ~(SCHED_FLAG_RESET_ON_FORK)) 3299 return -EINVAL; 3300 3301 /* 3302 * Valid priorities for SCHED_FIFO and SCHED_RR are 3303 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL, 3304 * SCHED_BATCH and SCHED_IDLE is 0. 3305 */ 3306 if ((p->mm && attr->sched_priority > MAX_USER_RT_PRIO-1) || 3307 (!p->mm && attr->sched_priority > MAX_RT_PRIO-1)) 3308 return -EINVAL; 3309 if ((dl_policy(policy) && !__checkparam_dl(attr)) || 3310 (rt_policy(policy) != (attr->sched_priority != 0))) 3311 return -EINVAL; 3312 3313 /* 3314 * Allow unprivileged RT tasks to decrease priority: 3315 */ 3316 if (user && !capable(CAP_SYS_NICE)) { 3317 if (fair_policy(policy)) { 3318 if (attr->sched_nice < task_nice(p) && 3319 !can_nice(p, attr->sched_nice)) 3320 return -EPERM; 3321 } 3322 3323 if (rt_policy(policy)) { 3324 unsigned long rlim_rtprio = 3325 task_rlimit(p, RLIMIT_RTPRIO); 3326 3327 /* can't set/change the rt policy */ 3328 if (policy != p->policy && !rlim_rtprio) 3329 return -EPERM; 3330 3331 /* can't increase priority */ 3332 if (attr->sched_priority > p->rt_priority && 3333 attr->sched_priority > rlim_rtprio) 3334 return -EPERM; 3335 } 3336 3337 /* 3338 * Can't set/change SCHED_DEADLINE policy at all for now 3339 * (safest behavior); in the future we would like to allow 3340 * unprivileged DL tasks to increase their relative deadline 3341 * or reduce their runtime (both ways reducing utilization) 3342 */ 3343 if (dl_policy(policy)) 3344 return -EPERM; 3345 3346 /* 3347 * Treat SCHED_IDLE as nice 20. Only allow a switch to 3348 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it. 3349 */ 3350 if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) { 3351 if (!can_nice(p, task_nice(p))) 3352 return -EPERM; 3353 } 3354 3355 /* can't change other user's priorities */ 3356 if (!check_same_owner(p)) 3357 return -EPERM; 3358 3359 /* Normal users shall not reset the sched_reset_on_fork flag */ 3360 if (p->sched_reset_on_fork && !reset_on_fork) 3361 return -EPERM; 3362 } 3363 3364 if (user) { 3365 retval = security_task_setscheduler(p); 3366 if (retval) 3367 return retval; 3368 } 3369 3370 /* 3371 * make sure no PI-waiters arrive (or leave) while we are 3372 * changing the priority of the task: 3373 * 3374 * To be able to change p->policy safely, the appropriate 3375 * runqueue lock must be held. 3376 */ 3377 rq = task_rq_lock(p, &flags); 3378 3379 /* 3380 * Changing the policy of the stop threads its a very bad idea 3381 */ 3382 if (p == rq->stop) { 3383 task_rq_unlock(rq, p, &flags); 3384 return -EINVAL; 3385 } 3386 3387 /* 3388 * If not changing anything there's no need to proceed further, 3389 * but store a possible modification of reset_on_fork. 3390 */ 3391 if (unlikely(policy == p->policy)) { 3392 if (fair_policy(policy) && attr->sched_nice != task_nice(p)) 3393 goto change; 3394 if (rt_policy(policy) && attr->sched_priority != p->rt_priority) 3395 goto change; 3396 if (dl_policy(policy)) 3397 goto change; 3398 3399 p->sched_reset_on_fork = reset_on_fork; 3400 task_rq_unlock(rq, p, &flags); 3401 return 0; 3402 } 3403change: 3404 3405 if (user) { 3406#ifdef CONFIG_RT_GROUP_SCHED 3407 /* 3408 * Do not allow realtime tasks into groups that have no runtime 3409 * assigned. 3410 */ 3411 if (rt_bandwidth_enabled() && rt_policy(policy) && 3412 task_group(p)->rt_bandwidth.rt_runtime == 0 && 3413 !task_group_is_autogroup(task_group(p))) { 3414 task_rq_unlock(rq, p, &flags); 3415 return -EPERM; 3416 } 3417#endif 3418#ifdef CONFIG_SMP 3419 if (dl_bandwidth_enabled() && dl_policy(policy)) { 3420 cpumask_t *span = rq->rd->span; 3421 3422 /* 3423 * Don't allow tasks with an affinity mask smaller than 3424 * the entire root_domain to become SCHED_DEADLINE. We 3425 * will also fail if there's no bandwidth available. 3426 */ 3427 if (!cpumask_subset(span, &p->cpus_allowed) || 3428 rq->rd->dl_bw.bw == 0) { 3429 task_rq_unlock(rq, p, &flags); 3430 return -EPERM; 3431 } 3432 } 3433#endif 3434 } 3435 3436 /* recheck policy now with rq lock held */ 3437 if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { 3438 policy = oldpolicy = -1; 3439 task_rq_unlock(rq, p, &flags); 3440 goto recheck; 3441 } 3442 3443 /* 3444 * If setscheduling to SCHED_DEADLINE (or changing the parameters 3445 * of a SCHED_DEADLINE task) we need to check if enough bandwidth 3446 * is available. 3447 */ 3448 if ((dl_policy(policy) || dl_task(p)) && dl_overflow(p, policy, attr)) { 3449 task_rq_unlock(rq, p, &flags); 3450 return -EBUSY; 3451 } 3452 3453 p->sched_reset_on_fork = reset_on_fork; 3454 oldprio = p->prio; 3455 3456 /* 3457 * Special case for priority boosted tasks. 3458 * 3459 * If the new priority is lower or equal (user space view) 3460 * than the current (boosted) priority, we just store the new 3461 * normal parameters and do not touch the scheduler class and 3462 * the runqueue. This will be done when the task deboost 3463 * itself. 3464 */ 3465 if (rt_mutex_check_prio(p, newprio)) { 3466 __setscheduler_params(p, attr); 3467 task_rq_unlock(rq, p, &flags); 3468 return 0; 3469 } 3470 3471 on_rq = p->on_rq; 3472 running = task_current(rq, p); 3473 if (on_rq) 3474 dequeue_task(rq, p, 0); 3475 if (running) 3476 p->sched_class->put_prev_task(rq, p); 3477 3478 prev_class = p->sched_class; 3479 __setscheduler(rq, p, attr); 3480 3481 if (running) 3482 p->sched_class->set_curr_task(rq); 3483 if (on_rq) { 3484 /* 3485 * We enqueue to tail when the priority of a task is 3486 * increased (user space view). 3487 */ 3488 enqueue_task(rq, p, oldprio <= p->prio ? ENQUEUE_HEAD : 0); 3489 } 3490 3491 check_class_changed(rq, p, prev_class, oldprio); 3492 task_rq_unlock(rq, p, &flags); 3493 3494 rt_mutex_adjust_pi(p); 3495 3496 return 0; 3497} 3498 3499static int _sched_setscheduler(struct task_struct *p, int policy, 3500 const struct sched_param *param, bool check) 3501{ 3502 struct sched_attr attr = { 3503 .sched_policy = policy, 3504 .sched_priority = param->sched_priority, 3505 .sched_nice = PRIO_TO_NICE(p->static_prio), 3506 }; 3507 3508 /* 3509 * Fixup the legacy SCHED_RESET_ON_FORK hack 3510 */ 3511 if (policy & SCHED_RESET_ON_FORK) { 3512 attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK; 3513 policy &= ~SCHED_RESET_ON_FORK; 3514 attr.sched_policy = policy; 3515 } 3516 3517 return __sched_setscheduler(p, &attr, check); 3518} 3519/** 3520 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. 3521 * @p: the task in question. 3522 * @policy: new policy. 3523 * @param: structure containing the new RT priority. 3524 * 3525 * Return: 0 on success. An error code otherwise. 3526 * 3527 * NOTE that the task may be already dead. 3528 */ 3529int sched_setscheduler(struct task_struct *p, int policy, 3530 const struct sched_param *param) 3531{ 3532 return _sched_setscheduler(p, policy, param, true); 3533} 3534EXPORT_SYMBOL_GPL(sched_setscheduler); 3535 3536int sched_setattr(struct task_struct *p, const struct sched_attr *attr) 3537{ 3538 return __sched_setscheduler(p, attr, true); 3539} 3540EXPORT_SYMBOL_GPL(sched_setattr); 3541 3542/** 3543 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace. 3544 * @p: the task in question. 3545 * @policy: new policy. 3546 * @param: structure containing the new RT priority. 3547 * 3548 * Just like sched_setscheduler, only don't bother checking if the 3549 * current context has permission. For example, this is needed in 3550 * stop_machine(): we create temporary high priority worker threads, 3551 * but our caller might not have that capability. 3552 * 3553 * Return: 0 on success. An error code otherwise. 3554 */ 3555int sched_setscheduler_nocheck(struct task_struct *p, int policy, 3556 const struct sched_param *param) 3557{ 3558 return _sched_setscheduler(p, policy, param, false); 3559} 3560 3561static int 3562do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) 3563{ 3564 struct sched_param lparam; 3565 struct task_struct *p; 3566 int retval; 3567 3568 if (!param || pid < 0) 3569 return -EINVAL; 3570 if (copy_from_user(&lparam, param, sizeof(struct sched_param))) 3571 return -EFAULT; 3572 3573 rcu_read_lock(); 3574 retval = -ESRCH; 3575 p = find_process_by_pid(pid); 3576 if (p != NULL) 3577 retval = sched_setscheduler(p, policy, &lparam); 3578 rcu_read_unlock(); 3579 3580 return retval; 3581} 3582 3583/* 3584 * Mimics kernel/events/core.c perf_copy_attr(). 3585 */ 3586static int sched_copy_attr(struct sched_attr __user *uattr, 3587 struct sched_attr *attr) 3588{ 3589 u32 size; 3590 int ret; 3591 3592 if (!access_ok(VERIFY_WRITE, uattr, SCHED_ATTR_SIZE_VER0)) 3593 return -EFAULT; 3594 3595 /* 3596 * zero the full structure, so that a short copy will be nice. 3597 */ 3598 memset(attr, 0, sizeof(*attr)); 3599 3600 ret = get_user(size, &uattr->size); 3601 if (ret) 3602 return ret; 3603 3604 if (size > PAGE_SIZE) /* silly large */ 3605 goto err_size; 3606 3607 if (!size) /* abi compat */ 3608 size = SCHED_ATTR_SIZE_VER0; 3609 3610 if (size < SCHED_ATTR_SIZE_VER0) 3611 goto err_size; 3612 3613 /* 3614 * If we're handed a bigger struct than we know of, 3615 * ensure all the unknown bits are 0 - i.e. new 3616 * user-space does not rely on any kernel feature 3617 * extensions we dont know about yet. 3618 */ 3619 if (size > sizeof(*attr)) { 3620 unsigned char __user *addr; 3621 unsigned char __user *end; 3622 unsigned char val; 3623 3624 addr = (void __user *)uattr + sizeof(*attr); 3625 end = (void __user *)uattr + size; 3626 3627 for (; addr < end; addr++) { 3628 ret = get_user(val, addr); 3629 if (ret) 3630 return ret; 3631 if (val) 3632 goto err_size; 3633 } 3634 size = sizeof(*attr); 3635 } 3636 3637 ret = copy_from_user(attr, uattr, size); 3638 if (ret) 3639 return -EFAULT; 3640 3641 /* 3642 * XXX: do we want to be lenient like existing syscalls; or do we want 3643 * to be strict and return an error on out-of-bounds values? 3644 */ 3645 attr->sched_nice = clamp(attr->sched_nice, MIN_NICE, MAX_NICE); 3646 3647out: 3648 return ret; 3649 3650err_size: 3651 put_user(sizeof(*attr), &uattr->size); 3652 ret = -E2BIG; 3653 goto out; 3654} 3655 3656/** 3657 * sys_sched_setscheduler - set/change the scheduler policy and RT priority 3658 * @pid: the pid in question. 3659 * @policy: new policy. 3660 * @param: structure containing the new RT priority. 3661 * 3662 * Return: 0 on success. An error code otherwise. 3663 */ 3664SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy, 3665 struct sched_param __user *, param) 3666{ 3667 /* negative values for policy are not valid */ 3668 if (policy < 0) 3669 return -EINVAL; 3670 3671 return do_sched_setscheduler(pid, policy, param); 3672} 3673 3674/** 3675 * sys_sched_setparam - set/change the RT priority of a thread 3676 * @pid: the pid in question. 3677 * @param: structure containing the new RT priority. 3678 * 3679 * Return: 0 on success. An error code otherwise. 3680 */ 3681SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param) 3682{ 3683 return do_sched_setscheduler(pid, -1, param); 3684} 3685 3686/** 3687 * sys_sched_setattr - same as above, but with extended sched_attr 3688 * @pid: the pid in question. 3689 * @uattr: structure containing the extended parameters. 3690 */ 3691SYSCALL_DEFINE3(sched_setattr, pid_t, pid, struct sched_attr __user *, uattr, 3692 unsigned int, flags) 3693{ 3694 struct sched_attr attr; 3695 struct task_struct *p; 3696 int retval; 3697 3698 if (!uattr || pid < 0 || flags) 3699 return -EINVAL; 3700 3701 if (sched_copy_attr(uattr, &attr)) 3702 return -EFAULT; 3703 3704 rcu_read_lock(); 3705 retval = -ESRCH; 3706 p = find_process_by_pid(pid); 3707 if (p != NULL) 3708 retval = sched_setattr(p, &attr); 3709 rcu_read_unlock(); 3710 3711 return retval; 3712} 3713 3714/** 3715 * sys_sched_getscheduler - get the policy (scheduling class) of a thread 3716 * @pid: the pid in question. 3717 * 3718 * Return: On success, the policy of the thread. Otherwise, a negative error 3719 * code. 3720 */ 3721SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid) 3722{ 3723 struct task_struct *p; 3724 int retval; 3725 3726 if (pid < 0) 3727 return -EINVAL; 3728 3729 retval = -ESRCH; 3730 rcu_read_lock(); 3731 p = find_process_by_pid(pid); 3732 if (p) { 3733 retval = security_task_getscheduler(p); 3734 if (!retval) 3735 retval = p->policy 3736 | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0); 3737 } 3738 rcu_read_unlock(); 3739 return retval; 3740} 3741 3742/** 3743 * sys_sched_getparam - get the RT priority of a thread 3744 * @pid: the pid in question. 3745 * @param: structure containing the RT priority. 3746 * 3747 * Return: On success, 0 and the RT priority is in @param. Otherwise, an error 3748 * code. 3749 */ 3750SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param) 3751{ 3752 struct sched_param lp; 3753 struct task_struct *p; 3754 int retval; 3755 3756 if (!param || pid < 0) 3757 return -EINVAL; 3758 3759 rcu_read_lock(); 3760 p = find_process_by_pid(pid); 3761 retval = -ESRCH; 3762 if (!p) 3763 goto out_unlock; 3764 3765 retval = security_task_getscheduler(p); 3766 if (retval) 3767 goto out_unlock; 3768 3769 if (task_has_dl_policy(p)) { 3770 retval = -EINVAL; 3771 goto out_unlock; 3772 } 3773 lp.sched_priority = p->rt_priority; 3774 rcu_read_unlock(); 3775 3776 /* 3777 * This one might sleep, we cannot do it with a spinlock held ... 3778 */ 3779 retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; 3780 3781 return retval; 3782 3783out_unlock: 3784 rcu_read_unlock(); 3785 return retval; 3786} 3787 3788static int sched_read_attr(struct sched_attr __user *uattr, 3789 struct sched_attr *attr, 3790 unsigned int usize) 3791{ 3792 int ret; 3793 3794 if (!access_ok(VERIFY_WRITE, uattr, usize)) 3795 return -EFAULT; 3796 3797 /* 3798 * If we're handed a smaller struct than we know of, 3799 * ensure all the unknown bits are 0 - i.e. old 3800 * user-space does not get uncomplete information. 3801 */ 3802 if (usize < sizeof(*attr)) { 3803 unsigned char *addr; 3804 unsigned char *end; 3805 3806 addr = (void *)attr + usize; 3807 end = (void *)attr + sizeof(*attr); 3808 3809 for (; addr < end; addr++) { 3810 if (*addr) 3811 goto err_size; 3812 } 3813 3814 attr->size = usize; 3815 } 3816 3817 ret = copy_to_user(uattr, attr, attr->size); 3818 if (ret) 3819 return -EFAULT; 3820 3821out: 3822 return ret; 3823 3824err_size: 3825 ret = -E2BIG; 3826 goto out; 3827} 3828 3829/** 3830 * sys_sched_getattr - similar to sched_getparam, but with sched_attr 3831 * @pid: the pid in question. 3832 * @uattr: structure containing the extended parameters. 3833 * @size: sizeof(attr) for fwd/bwd comp. 3834 */ 3835SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr, 3836 unsigned int, size, unsigned int, flags) 3837{ 3838 struct sched_attr attr = { 3839 .size = sizeof(struct sched_attr), 3840 }; 3841 struct task_struct *p; 3842 int retval; 3843 3844 if (!uattr || pid < 0 || size > PAGE_SIZE || 3845 size < SCHED_ATTR_SIZE_VER0 || flags) 3846 return -EINVAL; 3847 3848 rcu_read_lock(); 3849 p = find_process_by_pid(pid); 3850 retval = -ESRCH; 3851 if (!p) 3852 goto out_unlock; 3853 3854 retval = security_task_getscheduler(p); 3855 if (retval) 3856 goto out_unlock; 3857 3858 attr.sched_policy = p->policy; 3859 if (p->sched_reset_on_fork) 3860 attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK; 3861 if (task_has_dl_policy(p)) 3862 __getparam_dl(p, &attr); 3863 else if (task_has_rt_policy(p)) 3864 attr.sched_priority = p->rt_priority; 3865 else 3866 attr.sched_nice = task_nice(p); 3867 3868 rcu_read_unlock(); 3869 3870 retval = sched_read_attr(uattr, &attr, size); 3871 return retval; 3872 3873out_unlock: 3874 rcu_read_unlock(); 3875 return retval; 3876} 3877 3878long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) 3879{ 3880 cpumask_var_t cpus_allowed, new_mask; 3881 struct task_struct *p; 3882 int retval; 3883 3884 rcu_read_lock(); 3885 3886 p = find_process_by_pid(pid); 3887 if (!p) { 3888 rcu_read_unlock(); 3889 return -ESRCH; 3890 } 3891 3892 /* Prevent p going away */ 3893 get_task_struct(p); 3894 rcu_read_unlock(); 3895 3896 if (p->flags & PF_NO_SETAFFINITY) { 3897 retval = -EINVAL; 3898 goto out_put_task; 3899 } 3900 if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) { 3901 retval = -ENOMEM; 3902 goto out_put_task; 3903 } 3904 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) { 3905 retval = -ENOMEM; 3906 goto out_free_cpus_allowed; 3907 } 3908 retval = -EPERM; 3909 if (!check_same_owner(p)) { 3910 rcu_read_lock(); 3911 if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) { 3912 rcu_read_unlock(); 3913 goto out_unlock; 3914 } 3915 rcu_read_unlock(); 3916 } 3917 3918 retval = security_task_setscheduler(p); 3919 if (retval) 3920 goto out_unlock; 3921 3922 3923 cpuset_cpus_allowed(p, cpus_allowed); 3924 cpumask_and(new_mask, in_mask, cpus_allowed); 3925 3926 /* 3927 * Since bandwidth control happens on root_domain basis, 3928 * if admission test is enabled, we only admit -deadline 3929 * tasks allowed to run on all the CPUs in the task's 3930 * root_domain. 3931 */ 3932#ifdef CONFIG_SMP 3933 if (task_has_dl_policy(p)) { 3934 const struct cpumask *span = task_rq(p)->rd->span; 3935 3936 if (dl_bandwidth_enabled() && !cpumask_subset(span, new_mask)) { 3937 retval = -EBUSY; 3938 goto out_unlock; 3939 } 3940 } 3941#endif 3942again: 3943 retval = set_cpus_allowed_ptr(p, new_mask); 3944 3945 if (!retval) { 3946 cpuset_cpus_allowed(p, cpus_allowed); 3947 if (!cpumask_subset(new_mask, cpus_allowed)) { 3948 /* 3949 * We must have raced with a concurrent cpuset 3950 * update. Just reset the cpus_allowed to the 3951 * cpuset's cpus_allowed 3952 */ 3953 cpumask_copy(new_mask, cpus_allowed); 3954 goto again; 3955 } 3956 } 3957out_unlock: 3958 free_cpumask_var(new_mask); 3959out_free_cpus_allowed: 3960 free_cpumask_var(cpus_allowed); 3961out_put_task: 3962 put_task_struct(p); 3963 return retval; 3964} 3965 3966static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, 3967 struct cpumask *new_mask) 3968{ 3969 if (len < cpumask_size()) 3970 cpumask_clear(new_mask); 3971 else if (len > cpumask_size()) 3972 len = cpumask_size(); 3973 3974 return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; 3975} 3976 3977/** 3978 * sys_sched_setaffinity - set the cpu affinity of a process 3979 * @pid: pid of the process 3980 * @len: length in bytes of the bitmask pointed to by user_mask_ptr 3981 * @user_mask_ptr: user-space pointer to the new cpu mask 3982 * 3983 * Return: 0 on success. An error code otherwise. 3984 */ 3985SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len, 3986 unsigned long __user *, user_mask_ptr) 3987{ 3988 cpumask_var_t new_mask; 3989 int retval; 3990 3991 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) 3992 return -ENOMEM; 3993 3994 retval = get_user_cpu_mask(user_mask_ptr, len, new_mask); 3995 if (retval == 0) 3996 retval = sched_setaffinity(pid, new_mask); 3997 free_cpumask_var(new_mask); 3998 return retval; 3999} 4000 4001long sched_getaffinity(pid_t pid, struct cpumask *mask) 4002{ 4003 struct task_struct *p; 4004 unsigned long flags; 4005 int retval; 4006 4007 rcu_read_lock(); 4008 4009 retval = -ESRCH; 4010 p = find_process_by_pid(pid); 4011 if (!p) 4012 goto out_unlock; 4013 4014 retval = security_task_getscheduler(p); 4015 if (retval) 4016 goto out_unlock; 4017 4018 raw_spin_lock_irqsave(&p->pi_lock, flags); 4019 cpumask_and(mask, &p->cpus_allowed, cpu_active_mask); 4020 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 4021 4022out_unlock: 4023 rcu_read_unlock(); 4024 4025 return retval; 4026} 4027 4028/** 4029 * sys_sched_getaffinity - get the cpu affinity of a process 4030 * @pid: pid of the process 4031 * @len: length in bytes of the bitmask pointed to by user_mask_ptr 4032 * @user_mask_ptr: user-space pointer to hold the current cpu mask 4033 * 4034 * Return: 0 on success. An error code otherwise. 4035 */ 4036SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len, 4037 unsigned long __user *, user_mask_ptr) 4038{ 4039 int ret; 4040 cpumask_var_t mask; 4041 4042 if ((len * BITS_PER_BYTE) < nr_cpu_ids) 4043 return -EINVAL; 4044 if (len & (sizeof(unsigned long)-1)) 4045 return -EINVAL; 4046 4047 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) 4048 return -ENOMEM; 4049 4050 ret = sched_getaffinity(pid, mask); 4051 if (ret == 0) { 4052 size_t retlen = min_t(size_t, len, cpumask_size()); 4053 4054 if (copy_to_user(user_mask_ptr, mask, retlen)) 4055 ret = -EFAULT; 4056 else 4057 ret = retlen; 4058 } 4059 free_cpumask_var(mask); 4060 4061 return ret; 4062} 4063 4064/** 4065 * sys_sched_yield - yield the current processor to other threads. 4066 * 4067 * This function yields the current CPU to other tasks. If there are no 4068 * other threads running on this CPU then this function will return. 4069 * 4070 * Return: 0. 4071 */ 4072SYSCALL_DEFINE0(sched_yield) 4073{ 4074 struct rq *rq = this_rq_lock(); 4075 4076 schedstat_inc(rq, yld_count); 4077 current->sched_class->yield_task(rq); 4078 4079 /* 4080 * Since we are going to call schedule() anyway, there's 4081 * no need to preempt or enable interrupts: 4082 */ 4083 __release(rq->lock); 4084 spin_release(&rq->lock.dep_map, 1, _THIS_IP_); 4085 do_raw_spin_unlock(&rq->lock); 4086 sched_preempt_enable_no_resched(); 4087 4088 schedule(); 4089 4090 return 0; 4091} 4092 4093static void __cond_resched(void) 4094{ 4095 __preempt_count_add(PREEMPT_ACTIVE); 4096 __schedule(); 4097 __preempt_count_sub(PREEMPT_ACTIVE); 4098} 4099 4100int __sched _cond_resched(void) 4101{ 4102 if (should_resched()) { 4103 __cond_resched(); 4104 return 1; 4105 } 4106 return 0; 4107} 4108EXPORT_SYMBOL(_cond_resched); 4109 4110/* 4111 * __cond_resched_lock() - if a reschedule is pending, drop the given lock, 4112 * call schedule, and on return reacquire the lock. 4113 * 4114 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level 4115 * operations here to prevent schedule() from being called twice (once via 4116 * spin_unlock(), once by hand). 4117 */ 4118int __cond_resched_lock(spinlock_t *lock) 4119{ 4120 int resched = should_resched(); 4121 int ret = 0; 4122 4123 lockdep_assert_held(lock); 4124 4125 if (spin_needbreak(lock) || resched) { 4126 spin_unlock(lock); 4127 if (resched) 4128 __cond_resched(); 4129 else 4130 cpu_relax(); 4131 ret = 1; 4132 spin_lock(lock); 4133 } 4134 return ret; 4135} 4136EXPORT_SYMBOL(__cond_resched_lock); 4137 4138int __sched __cond_resched_softirq(void) 4139{ 4140 BUG_ON(!in_softirq()); 4141 4142 if (should_resched()) { 4143 local_bh_enable(); 4144 __cond_resched(); 4145 local_bh_disable(); 4146 return 1; 4147 } 4148 return 0; 4149} 4150EXPORT_SYMBOL(__cond_resched_softirq); 4151 4152/** 4153 * yield - yield the current processor to other threads. 4154 * 4155 * Do not ever use this function, there's a 99% chance you're doing it wrong. 4156 * 4157 * The scheduler is at all times free to pick the calling task as the most 4158 * eligible task to run, if removing the yield() call from your code breaks 4159 * it, its already broken. 4160 * 4161 * Typical broken usage is: 4162 * 4163 * while (!event) 4164 * yield(); 4165 * 4166 * where one assumes that yield() will let 'the other' process run that will 4167 * make event true. If the current task is a SCHED_FIFO task that will never 4168 * happen. Never use yield() as a progress guarantee!! 4169 * 4170 * If you want to use yield() to wait for something, use wait_event(). 4171 * If you want to use yield() to be 'nice' for others, use cond_resched(). 4172 * If you still want to use yield(), do not! 4173 */ 4174void __sched yield(void) 4175{ 4176 set_current_state(TASK_RUNNING); 4177 sys_sched_yield(); 4178} 4179EXPORT_SYMBOL(yield); 4180 4181/** 4182 * yield_to - yield the current processor to another thread in 4183 * your thread group, or accelerate that thread toward the 4184 * processor it's on. 4185 * @p: target task 4186 * @preempt: whether task preemption is allowed or not 4187 * 4188 * It's the caller's job to ensure that the target task struct 4189 * can't go away on us before we can do any checks. 4190 * 4191 * Return: 4192 * true (>0) if we indeed boosted the target task. 4193 * false (0) if we failed to boost the target. 4194 * -ESRCH if there's no task to yield to. 4195 */ 4196bool __sched yield_to(struct task_struct *p, bool preempt) 4197{ 4198 struct task_struct *curr = current; 4199 struct rq *rq, *p_rq; 4200 unsigned long flags; 4201 int yielded = 0; 4202 4203 local_irq_save(flags); 4204 rq = this_rq(); 4205 4206again: 4207 p_rq = task_rq(p); 4208 /* 4209 * If we're the only runnable task on the rq and target rq also 4210 * has only one task, there's absolutely no point in yielding. 4211 */ 4212 if (rq->nr_running == 1 && p_rq->nr_running == 1) { 4213 yielded = -ESRCH; 4214 goto out_irq; 4215 } 4216 4217 double_rq_lock(rq, p_rq); 4218 if (task_rq(p) != p_rq) { 4219 double_rq_unlock(rq, p_rq); 4220 goto again; 4221 } 4222 4223 if (!curr->sched_class->yield_to_task) 4224 goto out_unlock; 4225 4226 if (curr->sched_class != p->sched_class) 4227 goto out_unlock; 4228 4229 if (task_running(p_rq, p) || p->state) 4230 goto out_unlock; 4231 4232 yielded = curr->sched_class->yield_to_task(rq, p, preempt); 4233 if (yielded) { 4234 schedstat_inc(rq, yld_count); 4235 /* 4236 * Make p's CPU reschedule; pick_next_entity takes care of 4237 * fairness. 4238 */ 4239 if (preempt && rq != p_rq) 4240 resched_task(p_rq->curr); 4241 } 4242 4243out_unlock: 4244 double_rq_unlock(rq, p_rq); 4245out_irq: 4246 local_irq_restore(flags); 4247 4248 if (yielded > 0) 4249 schedule(); 4250 4251 return yielded; 4252} 4253EXPORT_SYMBOL_GPL(yield_to); 4254 4255/* 4256 * This task is about to go to sleep on IO. Increment rq->nr_iowait so 4257 * that process accounting knows that this is a task in IO wait state. 4258 */ 4259void __sched io_schedule(void) 4260{ 4261 struct rq *rq = raw_rq(); 4262 4263 delayacct_blkio_start(); 4264 atomic_inc(&rq->nr_iowait); 4265 blk_flush_plug(current); 4266 current->in_iowait = 1; 4267 schedule(); 4268 current->in_iowait = 0; 4269 atomic_dec(&rq->nr_iowait); 4270 delayacct_blkio_end(); 4271} 4272EXPORT_SYMBOL(io_schedule); 4273 4274long __sched io_schedule_timeout(long timeout) 4275{ 4276 struct rq *rq = raw_rq(); 4277 long ret; 4278 4279 delayacct_blkio_start(); 4280 atomic_inc(&rq->nr_iowait); 4281 blk_flush_plug(current); 4282 current->in_iowait = 1; 4283 ret = schedule_timeout(timeout); 4284 current->in_iowait = 0; 4285 atomic_dec(&rq->nr_iowait); 4286 delayacct_blkio_end(); 4287 return ret; 4288} 4289 4290/** 4291 * sys_sched_get_priority_max - return maximum RT priority. 4292 * @policy: scheduling class. 4293 * 4294 * Return: On success, this syscall returns the maximum 4295 * rt_priority that can be used by a given scheduling class. 4296 * On failure, a negative error code is returned. 4297 */ 4298SYSCALL_DEFINE1(sched_get_priority_max, int, policy) 4299{ 4300 int ret = -EINVAL; 4301 4302 switch (policy) { 4303 case SCHED_FIFO: 4304 case SCHED_RR: 4305 ret = MAX_USER_RT_PRIO-1; 4306 break; 4307 case SCHED_DEADLINE: 4308 case SCHED_NORMAL: 4309 case SCHED_BATCH: 4310 case SCHED_IDLE: 4311 ret = 0; 4312 break; 4313 } 4314 return ret; 4315} 4316 4317/** 4318 * sys_sched_get_priority_min - return minimum RT priority. 4319 * @policy: scheduling class. 4320 * 4321 * Return: On success, this syscall returns the minimum 4322 * rt_priority that can be used by a given scheduling class. 4323 * On failure, a negative error code is returned. 4324 */ 4325SYSCALL_DEFINE1(sched_get_priority_min, int, policy) 4326{ 4327 int ret = -EINVAL; 4328 4329 switch (policy) { 4330 case SCHED_FIFO: 4331 case SCHED_RR: 4332 ret = 1; 4333 break; 4334 case SCHED_DEADLINE: 4335 case SCHED_NORMAL: 4336 case SCHED_BATCH: 4337 case SCHED_IDLE: 4338 ret = 0; 4339 } 4340 return ret; 4341} 4342 4343/** 4344 * sys_sched_rr_get_interval - return the default timeslice of a process. 4345 * @pid: pid of the process. 4346 * @interval: userspace pointer to the timeslice value. 4347 * 4348 * this syscall writes the default timeslice value of a given process 4349 * into the user-space timespec buffer. A value of '0' means infinity. 4350 * 4351 * Return: On success, 0 and the timeslice is in @interval. Otherwise, 4352 * an error code. 4353 */ 4354SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid, 4355 struct timespec __user *, interval) 4356{ 4357 struct task_struct *p; 4358 unsigned int time_slice; 4359 unsigned long flags; 4360 struct rq *rq; 4361 int retval; 4362 struct timespec t; 4363 4364 if (pid < 0) 4365 return -EINVAL; 4366 4367 retval = -ESRCH; 4368 rcu_read_lock(); 4369 p = find_process_by_pid(pid); 4370 if (!p) 4371 goto out_unlock; 4372 4373 retval = security_task_getscheduler(p); 4374 if (retval) 4375 goto out_unlock; 4376 4377 rq = task_rq_lock(p, &flags); 4378 time_slice = 0; 4379 if (p->sched_class->get_rr_interval) 4380 time_slice = p->sched_class->get_rr_interval(rq, p); 4381 task_rq_unlock(rq, p, &flags); 4382 4383 rcu_read_unlock(); 4384 jiffies_to_timespec(time_slice, &t); 4385 retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; 4386 return retval; 4387 4388out_unlock: 4389 rcu_read_unlock(); 4390 return retval; 4391} 4392 4393static const char stat_nam[] = TASK_STATE_TO_CHAR_STR; 4394 4395void sched_show_task(struct task_struct *p) 4396{ 4397 unsigned long free = 0; 4398 int ppid; 4399 unsigned state; 4400 4401 state = p->state ? __ffs(p->state) + 1 : 0; 4402 printk(KERN_INFO "%-15.15s %c", p->comm, 4403 state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); 4404#if BITS_PER_LONG == 32 4405 if (state == TASK_RUNNING) 4406 printk(KERN_CONT " running "); 4407 else 4408 printk(KERN_CONT " %08lx ", thread_saved_pc(p)); 4409#else 4410 if (state == TASK_RUNNING) 4411 printk(KERN_CONT " running task "); 4412 else 4413 printk(KERN_CONT " %016lx ", thread_saved_pc(p)); 4414#endif 4415#ifdef CONFIG_DEBUG_STACK_USAGE 4416 free = stack_not_used(p); 4417#endif 4418 rcu_read_lock(); 4419 ppid = task_pid_nr(rcu_dereference(p->real_parent)); 4420 rcu_read_unlock(); 4421 printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free, 4422 task_pid_nr(p), ppid, 4423 (unsigned long)task_thread_info(p)->flags); 4424 4425 print_worker_info(KERN_INFO, p); 4426 show_stack(p, NULL); 4427} 4428 4429void show_state_filter(unsigned long state_filter) 4430{ 4431 struct task_struct *g, *p; 4432 4433#if BITS_PER_LONG == 32 4434 printk(KERN_INFO 4435 " task PC stack pid father\n"); 4436#else 4437 printk(KERN_INFO 4438 " task PC stack pid father\n"); 4439#endif 4440 rcu_read_lock(); 4441 do_each_thread(g, p) { 4442 /* 4443 * reset the NMI-timeout, listing all files on a slow 4444 * console might take a lot of time: 4445 */ 4446 touch_nmi_watchdog(); 4447 if (!state_filter || (p->state & state_filter)) 4448 sched_show_task(p); 4449 } while_each_thread(g, p); 4450 4451 touch_all_softlockup_watchdogs(); 4452 4453#ifdef CONFIG_SCHED_DEBUG 4454 sysrq_sched_debug_show(); 4455#endif 4456 rcu_read_unlock(); 4457 /* 4458 * Only show locks if all tasks are dumped: 4459 */ 4460 if (!state_filter) 4461 debug_show_all_locks(); 4462} 4463 4464void init_idle_bootup_task(struct task_struct *idle) 4465{ 4466 idle->sched_class = &idle_sched_class; 4467} 4468 4469/** 4470 * init_idle - set up an idle thread for a given CPU 4471 * @idle: task in question 4472 * @cpu: cpu the idle task belongs to 4473 * 4474 * NOTE: this function does not set the idle thread's NEED_RESCHED 4475 * flag, to make booting more robust. 4476 */ 4477void init_idle(struct task_struct *idle, int cpu) 4478{ 4479 struct rq *rq = cpu_rq(cpu); 4480 unsigned long flags; 4481 4482 raw_spin_lock_irqsave(&rq->lock, flags); 4483 4484 __sched_fork(0, idle); 4485 idle->state = TASK_RUNNING; 4486 idle->se.exec_start = sched_clock(); 4487 4488 do_set_cpus_allowed(idle, cpumask_of(cpu)); 4489 /* 4490 * We're having a chicken and egg problem, even though we are 4491 * holding rq->lock, the cpu isn't yet set to this cpu so the 4492 * lockdep check in task_group() will fail. 4493 * 4494 * Similar case to sched_fork(). / Alternatively we could 4495 * use task_rq_lock() here and obtain the other rq->lock. 4496 * 4497 * Silence PROVE_RCU 4498 */ 4499 rcu_read_lock(); 4500 __set_task_cpu(idle, cpu); 4501 rcu_read_unlock(); 4502 4503 rq->curr = rq->idle = idle; 4504 idle->on_rq = 1; 4505#if defined(CONFIG_SMP) 4506 idle->on_cpu = 1; 4507#endif 4508 raw_spin_unlock_irqrestore(&rq->lock, flags); 4509 4510 /* Set the preempt count _outside_ the spinlocks! */ 4511 init_idle_preempt_count(idle, cpu); 4512 4513 /* 4514 * The idle tasks have their own, simple scheduling class: 4515 */ 4516 idle->sched_class = &idle_sched_class; 4517 ftrace_graph_init_idle_task(idle, cpu); 4518 vtime_init_idle(idle, cpu); 4519#if defined(CONFIG_SMP) 4520 sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu); 4521#endif 4522} 4523 4524#ifdef CONFIG_SMP 4525void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) 4526{ 4527 if (p->sched_class && p->sched_class->set_cpus_allowed) 4528 p->sched_class->set_cpus_allowed(p, new_mask); 4529 4530 cpumask_copy(&p->cpus_allowed, new_mask); 4531 p->nr_cpus_allowed = cpumask_weight(new_mask); 4532} 4533 4534/* 4535 * This is how migration works: 4536 * 4537 * 1) we invoke migration_cpu_stop() on the target CPU using 4538 * stop_one_cpu(). 4539 * 2) stopper starts to run (implicitly forcing the migrated thread 4540 * off the CPU) 4541 * 3) it checks whether the migrated task is still in the wrong runqueue. 4542 * 4) if it's in the wrong runqueue then the migration thread removes 4543 * it and puts it into the right queue. 4544 * 5) stopper completes and stop_one_cpu() returns and the migration 4545 * is done. 4546 */ 4547 4548/* 4549 * Change a given task's CPU affinity. Migrate the thread to a 4550 * proper CPU and schedule it away if the CPU it's executing on 4551 * is removed from the allowed bitmask. 4552 * 4553 * NOTE: the caller must have a valid reference to the task, the 4554 * task must not exit() & deallocate itself prematurely. The 4555 * call is not atomic; no spinlocks may be held. 4556 */ 4557int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) 4558{ 4559 unsigned long flags; 4560 struct rq *rq; 4561 unsigned int dest_cpu; 4562 int ret = 0; 4563 4564 rq = task_rq_lock(p, &flags); 4565 4566 if (cpumask_equal(&p->cpus_allowed, new_mask)) 4567 goto out; 4568 4569 if (!cpumask_intersects(new_mask, cpu_active_mask)) { 4570 ret = -EINVAL; 4571 goto out; 4572 } 4573 4574 do_set_cpus_allowed(p, new_mask); 4575 4576 /* Can the task run on the task's current CPU? If so, we're done */ 4577 if (cpumask_test_cpu(task_cpu(p), new_mask)) 4578 goto out; 4579 4580 dest_cpu = cpumask_any_and(cpu_active_mask, new_mask); 4581 if (p->on_rq) { 4582 struct migration_arg arg = { p, dest_cpu }; 4583 /* Need help from migration thread: drop lock and wait. */ 4584 task_rq_unlock(rq, p, &flags); 4585 stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg); 4586 tlb_migrate_finish(p->mm); 4587 return 0; 4588 } 4589out: 4590 task_rq_unlock(rq, p, &flags); 4591 4592 return ret; 4593} 4594EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr); 4595 4596/* 4597 * Move (not current) task off this cpu, onto dest cpu. We're doing 4598 * this because either it can't run here any more (set_cpus_allowed() 4599 * away from this CPU, or CPU going down), or because we're 4600 * attempting to rebalance this task on exec (sched_exec). 4601 * 4602 * So we race with normal scheduler movements, but that's OK, as long 4603 * as the task is no longer on this CPU. 4604 * 4605 * Returns non-zero if task was successfully migrated. 4606 */ 4607static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) 4608{ 4609 struct rq *rq_dest, *rq_src; 4610 int ret = 0; 4611 4612 if (unlikely(!cpu_active(dest_cpu))) 4613 return ret; 4614 4615 rq_src = cpu_rq(src_cpu); 4616 rq_dest = cpu_rq(dest_cpu); 4617 4618 raw_spin_lock(&p->pi_lock); 4619 double_rq_lock(rq_src, rq_dest); 4620 /* Already moved. */ 4621 if (task_cpu(p) != src_cpu) 4622 goto done; 4623 /* Affinity changed (again). */ 4624 if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) 4625 goto fail; 4626 4627 /* 4628 * If we're not on a rq, the next wake-up will ensure we're 4629 * placed properly. 4630 */ 4631 if (p->on_rq) { 4632 dequeue_task(rq_src, p, 0); 4633 set_task_cpu(p, dest_cpu); 4634 enqueue_task(rq_dest, p, 0); 4635 check_preempt_curr(rq_dest, p, 0); 4636 } 4637done: 4638 ret = 1; 4639fail: 4640 double_rq_unlock(rq_src, rq_dest); 4641 raw_spin_unlock(&p->pi_lock); 4642 return ret; 4643} 4644 4645#ifdef CONFIG_NUMA_BALANCING 4646/* Migrate current task p to target_cpu */ 4647int migrate_task_to(struct task_struct *p, int target_cpu) 4648{ 4649 struct migration_arg arg = { p, target_cpu }; 4650 int curr_cpu = task_cpu(p); 4651 4652 if (curr_cpu == target_cpu) 4653 return 0; 4654 4655 if (!cpumask_test_cpu(target_cpu, tsk_cpus_allowed(p))) 4656 return -EINVAL; 4657 4658 /* TODO: This is not properly updating schedstats */ 4659 4660 trace_sched_move_numa(p, curr_cpu, target_cpu); 4661 return stop_one_cpu(curr_cpu, migration_cpu_stop, &arg); 4662} 4663 4664/* 4665 * Requeue a task on a given node and accurately track the number of NUMA 4666 * tasks on the runqueues 4667 */ 4668void sched_setnuma(struct task_struct *p, int nid) 4669{ 4670 struct rq *rq; 4671 unsigned long flags; 4672 bool on_rq, running; 4673 4674 rq = task_rq_lock(p, &flags); 4675 on_rq = p->on_rq; 4676 running = task_current(rq, p); 4677 4678 if (on_rq) 4679 dequeue_task(rq, p, 0); 4680 if (running) 4681 p->sched_class->put_prev_task(rq, p); 4682 4683 p->numa_preferred_nid = nid; 4684 4685 if (running) 4686 p->sched_class->set_curr_task(rq); 4687 if (on_rq) 4688 enqueue_task(rq, p, 0); 4689 task_rq_unlock(rq, p, &flags); 4690} 4691#endif 4692 4693/* 4694 * migration_cpu_stop - this will be executed by a highprio stopper thread 4695 * and performs thread migration by bumping thread off CPU then 4696 * 'pushing' onto another runqueue. 4697 */ 4698static int migration_cpu_stop(void *data) 4699{ 4700 struct migration_arg *arg = data; 4701 4702 /* 4703 * The original target cpu might have gone down and we might 4704 * be on another cpu but it doesn't matter. 4705 */ 4706 local_irq_disable(); 4707 __migrate_task(arg->task, raw_smp_processor_id(), arg->dest_cpu); 4708 local_irq_enable(); 4709 return 0; 4710} 4711 4712#ifdef CONFIG_HOTPLUG_CPU 4713 4714/* 4715 * Ensures that the idle task is using init_mm right before its cpu goes 4716 * offline. 4717 */ 4718void idle_task_exit(void) 4719{ 4720 struct mm_struct *mm = current->active_mm; 4721 4722 BUG_ON(cpu_online(smp_processor_id())); 4723 4724 if (mm != &init_mm) 4725 switch_mm(mm, &init_mm, current); 4726 mmdrop(mm); 4727} 4728 4729/* 4730 * Since this CPU is going 'away' for a while, fold any nr_active delta 4731 * we might have. Assumes we're called after migrate_tasks() so that the 4732 * nr_active count is stable. 4733 * 4734 * Also see the comment "Global load-average calculations". 4735 */ 4736static void calc_load_migrate(struct rq *rq) 4737{ 4738 long delta = calc_load_fold_active(rq); 4739 if (delta) 4740 atomic_long_add(delta, &calc_load_tasks); 4741} 4742 4743static void put_prev_task_fake(struct rq *rq, struct task_struct *prev) 4744{ 4745} 4746 4747static const struct sched_class fake_sched_class = { 4748 .put_prev_task = put_prev_task_fake, 4749}; 4750 4751static struct task_struct fake_task = { 4752 /* 4753 * Avoid pull_{rt,dl}_task() 4754 */ 4755 .prio = MAX_PRIO + 1, 4756 .sched_class = &fake_sched_class, 4757}; 4758 4759/* 4760 * Migrate all tasks from the rq, sleeping tasks will be migrated by 4761 * try_to_wake_up()->select_task_rq(). 4762 * 4763 * Called with rq->lock held even though we'er in stop_machine() and 4764 * there's no concurrency possible, we hold the required locks anyway 4765 * because of lock validation efforts. 4766 */ 4767static void migrate_tasks(unsigned int dead_cpu) 4768{ 4769 struct rq *rq = cpu_rq(dead_cpu); 4770 struct task_struct *next, *stop = rq->stop; 4771 int dest_cpu; 4772 4773 /* 4774 * Fudge the rq selection such that the below task selection loop 4775 * doesn't get stuck on the currently eligible stop task. 4776 * 4777 * We're currently inside stop_machine() and the rq is either stuck 4778 * in the stop_machine_cpu_stop() loop, or we're executing this code, 4779 * either way we should never end up calling schedule() until we're 4780 * done here. 4781 */ 4782 rq->stop = NULL; 4783 4784 /* 4785 * put_prev_task() and pick_next_task() sched 4786 * class method both need to have an up-to-date 4787 * value of rq->clock[_task] 4788 */ 4789 update_rq_clock(rq); 4790 4791 for ( ; ; ) { 4792 /* 4793 * There's this thread running, bail when that's the only 4794 * remaining thread. 4795 */ 4796 if (rq->nr_running == 1) 4797 break; 4798 4799 next = pick_next_task(rq, &fake_task); 4800 BUG_ON(!next); 4801 next->sched_class->put_prev_task(rq, next); 4802 4803 /* Find suitable destination for @next, with force if needed. */ 4804 dest_cpu = select_fallback_rq(dead_cpu, next); 4805 raw_spin_unlock(&rq->lock); 4806 4807 __migrate_task(next, dead_cpu, dest_cpu); 4808 4809 raw_spin_lock(&rq->lock); 4810 } 4811 4812 rq->stop = stop; 4813} 4814 4815#endif /* CONFIG_HOTPLUG_CPU */ 4816 4817#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL) 4818 4819static struct ctl_table sd_ctl_dir[] = { 4820 { 4821 .procname = "sched_domain", 4822 .mode = 0555, 4823 }, 4824 {} 4825}; 4826 4827static struct ctl_table sd_ctl_root[] = { 4828 { 4829 .procname = "kernel", 4830 .mode = 0555, 4831 .child = sd_ctl_dir, 4832 }, 4833 {} 4834}; 4835 4836static struct ctl_table *sd_alloc_ctl_entry(int n) 4837{ 4838 struct ctl_table *entry = 4839 kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL); 4840 4841 return entry; 4842} 4843 4844static void sd_free_ctl_entry(struct ctl_table **tablep) 4845{ 4846 struct ctl_table *entry; 4847 4848 /* 4849 * In the intermediate directories, both the child directory and 4850 * procname are dynamically allocated and could fail but the mode 4851 * will always be set. In the lowest directory the names are 4852 * static strings and all have proc handlers. 4853 */ 4854 for (entry = *tablep; entry->mode; entry++) { 4855 if (entry->child) 4856 sd_free_ctl_entry(&entry->child); 4857 if (entry->proc_handler == NULL) 4858 kfree(entry->procname); 4859 } 4860 4861 kfree(*tablep); 4862 *tablep = NULL; 4863} 4864 4865static int min_load_idx = 0; 4866static int max_load_idx = CPU_LOAD_IDX_MAX-1; 4867 4868static void 4869set_table_entry(struct ctl_table *entry, 4870 const char *procname, void *data, int maxlen, 4871 umode_t mode, proc_handler *proc_handler, 4872 bool load_idx) 4873{ 4874 entry->procname = procname; 4875 entry->data = data; 4876 entry->maxlen = maxlen; 4877 entry->mode = mode; 4878 entry->proc_handler = proc_handler; 4879 4880 if (load_idx) { 4881 entry->extra1 = &min_load_idx; 4882 entry->extra2 = &max_load_idx; 4883 } 4884} 4885 4886static struct ctl_table * 4887sd_alloc_ctl_domain_table(struct sched_domain *sd) 4888{ 4889 struct ctl_table *table = sd_alloc_ctl_entry(14); 4890 4891 if (table == NULL) 4892 return NULL; 4893 4894 set_table_entry(&table[0], "min_interval", &sd->min_interval, 4895 sizeof(long), 0644, proc_doulongvec_minmax, false); 4896 set_table_entry(&table[1], "max_interval", &sd->max_interval, 4897 sizeof(long), 0644, proc_doulongvec_minmax, false); 4898 set_table_entry(&table[2], "busy_idx", &sd->busy_idx, 4899 sizeof(int), 0644, proc_dointvec_minmax, true); 4900 set_table_entry(&table[3], "idle_idx", &sd->idle_idx, 4901 sizeof(int), 0644, proc_dointvec_minmax, true); 4902 set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx, 4903 sizeof(int), 0644, proc_dointvec_minmax, true); 4904 set_table_entry(&table[5], "wake_idx", &sd->wake_idx, 4905 sizeof(int), 0644, proc_dointvec_minmax, true); 4906 set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx, 4907 sizeof(int), 0644, proc_dointvec_minmax, true); 4908 set_table_entry(&table[7], "busy_factor", &sd->busy_factor, 4909 sizeof(int), 0644, proc_dointvec_minmax, false); 4910 set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct, 4911 sizeof(int), 0644, proc_dointvec_minmax, false); 4912 set_table_entry(&table[9], "cache_nice_tries", 4913 &sd->cache_nice_tries, 4914 sizeof(int), 0644, proc_dointvec_minmax, false); 4915 set_table_entry(&table[10], "flags", &sd->flags, 4916 sizeof(int), 0644, proc_dointvec_minmax, false); 4917 set_table_entry(&table[11], "max_newidle_lb_cost", 4918 &sd->max_newidle_lb_cost, 4919 sizeof(long), 0644, proc_doulongvec_minmax, false); 4920 set_table_entry(&table[12], "name", sd->name, 4921 CORENAME_MAX_SIZE, 0444, proc_dostring, false); 4922 /* &table[13] is terminator */ 4923 4924 return table; 4925} 4926 4927static struct ctl_table *sd_alloc_ctl_cpu_table(int cpu) 4928{ 4929 struct ctl_table *entry, *table; 4930 struct sched_domain *sd; 4931 int domain_num = 0, i; 4932 char buf[32]; 4933 4934 for_each_domain(cpu, sd) 4935 domain_num++; 4936 entry = table = sd_alloc_ctl_entry(domain_num + 1); 4937 if (table == NULL) 4938 return NULL; 4939 4940 i = 0; 4941 for_each_domain(cpu, sd) { 4942 snprintf(buf, 32, "domain%d", i); 4943 entry->procname = kstrdup(buf, GFP_KERNEL); 4944 entry->mode = 0555; 4945 entry->child = sd_alloc_ctl_domain_table(sd); 4946 entry++; 4947 i++; 4948 } 4949 return table; 4950} 4951 4952static struct ctl_table_header *sd_sysctl_header; 4953static void register_sched_domain_sysctl(void) 4954{ 4955 int i, cpu_num = num_possible_cpus(); 4956 struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1); 4957 char buf[32]; 4958 4959 WARN_ON(sd_ctl_dir[0].child); 4960 sd_ctl_dir[0].child = entry; 4961 4962 if (entry == NULL) 4963 return; 4964 4965 for_each_possible_cpu(i) { 4966 snprintf(buf, 32, "cpu%d", i); 4967 entry->procname = kstrdup(buf, GFP_KERNEL); 4968 entry->mode = 0555; 4969 entry->child = sd_alloc_ctl_cpu_table(i); 4970 entry++; 4971 } 4972 4973 WARN_ON(sd_sysctl_header); 4974 sd_sysctl_header = register_sysctl_table(sd_ctl_root); 4975} 4976 4977/* may be called multiple times per register */ 4978static void unregister_sched_domain_sysctl(void) 4979{ 4980 if (sd_sysctl_header) 4981 unregister_sysctl_table(sd_sysctl_header); 4982 sd_sysctl_header = NULL; 4983 if (sd_ctl_dir[0].child) 4984 sd_free_ctl_entry(&sd_ctl_dir[0].child); 4985} 4986#else 4987static void register_sched_domain_sysctl(void) 4988{ 4989} 4990static void unregister_sched_domain_sysctl(void) 4991{ 4992} 4993#endif 4994 4995static void set_rq_online(struct rq *rq) 4996{ 4997 if (!rq->online) { 4998 const struct sched_class *class; 4999 5000 cpumask_set_cpu(rq->cpu, rq->rd->online); 5001 rq->online = 1; 5002 5003 for_each_class(class) { 5004 if (class->rq_online) 5005 class->rq_online(rq); 5006 } 5007 } 5008} 5009 5010static void set_rq_offline(struct rq *rq) 5011{ 5012 if (rq->online) { 5013 const struct sched_class *class; 5014 5015 for_each_class(class) { 5016 if (class->rq_offline) 5017 class->rq_offline(rq); 5018 } 5019 5020 cpumask_clear_cpu(rq->cpu, rq->rd->online); 5021 rq->online = 0; 5022 } 5023} 5024 5025/* 5026 * migration_call - callback that gets triggered when a CPU is added. 5027 * Here we can start up the necessary migration thread for the new CPU. 5028 */ 5029static int 5030migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) 5031{ 5032 int cpu = (long)hcpu; 5033 unsigned long flags; 5034 struct rq *rq = cpu_rq(cpu); 5035 5036 switch (action & ~CPU_TASKS_FROZEN) { 5037 5038 case CPU_UP_PREPARE: 5039 rq->calc_load_update = calc_load_update; 5040 break; 5041 5042 case CPU_ONLINE: 5043 /* Update our root-domain */ 5044 raw_spin_lock_irqsave(&rq->lock, flags); 5045 if (rq->rd) { 5046 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); 5047 5048 set_rq_online(rq); 5049 } 5050 raw_spin_unlock_irqrestore(&rq->lock, flags); 5051 break; 5052 5053#ifdef CONFIG_HOTPLUG_CPU 5054 case CPU_DYING: 5055 sched_ttwu_pending(); 5056 /* Update our root-domain */ 5057 raw_spin_lock_irqsave(&rq->lock, flags); 5058 if (rq->rd) { 5059 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); 5060 set_rq_offline(rq); 5061 } 5062 migrate_tasks(cpu); 5063 BUG_ON(rq->nr_running != 1); /* the migration thread */ 5064 raw_spin_unlock_irqrestore(&rq->lock, flags); 5065 break; 5066 5067 case CPU_DEAD: 5068 calc_load_migrate(rq); 5069 break; 5070#endif 5071 } 5072 5073 update_max_interval(); 5074 5075 return NOTIFY_OK; 5076} 5077 5078/* 5079 * Register at high priority so that task migration (migrate_all_tasks) 5080 * happens before everything else. This has to be lower priority than 5081 * the notifier in the perf_event subsystem, though. 5082 */ 5083static struct notifier_block migration_notifier = { 5084 .notifier_call = migration_call, 5085 .priority = CPU_PRI_MIGRATION, 5086}; 5087 5088static int sched_cpu_active(struct notifier_block *nfb, 5089 unsigned long action, void *hcpu) 5090{ 5091 switch (action & ~CPU_TASKS_FROZEN) { 5092 case CPU_STARTING: 5093 case CPU_DOWN_FAILED: 5094 set_cpu_active((long)hcpu, true); 5095 return NOTIFY_OK; 5096 default: 5097 return NOTIFY_DONE; 5098 } 5099} 5100 5101static int sched_cpu_inactive(struct notifier_block *nfb, 5102 unsigned long action, void *hcpu) 5103{ 5104 unsigned long flags; 5105 long cpu = (long)hcpu; 5106 5107 switch (action & ~CPU_TASKS_FROZEN) { 5108 case CPU_DOWN_PREPARE: 5109 set_cpu_active(cpu, false); 5110 5111 /* explicitly allow suspend */ 5112 if (!(action & CPU_TASKS_FROZEN)) { 5113 struct dl_bw *dl_b = dl_bw_of(cpu); 5114 bool overflow; 5115 int cpus; 5116 5117 raw_spin_lock_irqsave(&dl_b->lock, flags); 5118 cpus = dl_bw_cpus(cpu); 5119 overflow = __dl_overflow(dl_b, cpus, 0, 0); 5120 raw_spin_unlock_irqrestore(&dl_b->lock, flags); 5121 5122 if (overflow) 5123 return notifier_from_errno(-EBUSY); 5124 } 5125 return NOTIFY_OK; 5126 } 5127 5128 return NOTIFY_DONE; 5129} 5130 5131static int __init migration_init(void) 5132{ 5133 void *cpu = (void *)(long)smp_processor_id(); 5134 int err; 5135 5136 /* Initialize migration for the boot CPU */ 5137 err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); 5138 BUG_ON(err == NOTIFY_BAD); 5139 migration_call(&migration_notifier, CPU_ONLINE, cpu); 5140 register_cpu_notifier(&migration_notifier); 5141 5142 /* Register cpu active notifiers */ 5143 cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE); 5144 cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE); 5145 5146 return 0; 5147} 5148early_initcall(migration_init); 5149#endif 5150 5151#ifdef CONFIG_SMP 5152 5153static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */ 5154 5155#ifdef CONFIG_SCHED_DEBUG 5156 5157static __read_mostly int sched_debug_enabled; 5158 5159static int __init sched_debug_setup(char *str) 5160{ 5161 sched_debug_enabled = 1; 5162 5163 return 0; 5164} 5165early_param("sched_debug", sched_debug_setup); 5166 5167static inline bool sched_debug(void) 5168{ 5169 return sched_debug_enabled; 5170} 5171 5172static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, 5173 struct cpumask *groupmask) 5174{ 5175 struct sched_group *group = sd->groups; 5176 char str[256]; 5177 5178 cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd)); 5179 cpumask_clear(groupmask); 5180 5181 printk(KERN_DEBUG "%*s domain %d: ", level, "", level); 5182 5183 if (!(sd->flags & SD_LOAD_BALANCE)) { 5184 printk("does not load-balance\n"); 5185 if (sd->parent) 5186 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain" 5187 " has parent"); 5188 return -1; 5189 } 5190 5191 printk(KERN_CONT "span %s level %s\n", str, sd->name); 5192 5193 if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) { 5194 printk(KERN_ERR "ERROR: domain->span does not contain " 5195 "CPU%d\n", cpu); 5196 } 5197 if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) { 5198 printk(KERN_ERR "ERROR: domain->groups does not contain" 5199 " CPU%d\n", cpu); 5200 } 5201 5202 printk(KERN_DEBUG "%*s groups:", level + 1, ""); 5203 do { 5204 if (!group) { 5205 printk("\n"); 5206 printk(KERN_ERR "ERROR: group is NULL\n"); 5207 break; 5208 } 5209 5210 /* 5211 * Even though we initialize ->power to something semi-sane, 5212 * we leave power_orig unset. This allows us to detect if 5213 * domain iteration is still funny without causing /0 traps. 5214 */ 5215 if (!group->sgp->power_orig) { 5216 printk(KERN_CONT "\n"); 5217 printk(KERN_ERR "ERROR: domain->cpu_power not " 5218 "set\n"); 5219 break; 5220 } 5221 5222 if (!cpumask_weight(sched_group_cpus(group))) { 5223 printk(KERN_CONT "\n"); 5224 printk(KERN_ERR "ERROR: empty group\n"); 5225 break; 5226 } 5227 5228 if (!(sd->flags & SD_OVERLAP) && 5229 cpumask_intersects(groupmask, sched_group_cpus(group))) { 5230 printk(KERN_CONT "\n"); 5231 printk(KERN_ERR "ERROR: repeated CPUs\n"); 5232 break; 5233 } 5234 5235 cpumask_or(groupmask, groupmask, sched_group_cpus(group)); 5236 5237 cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group)); 5238 5239 printk(KERN_CONT " %s", str); 5240 if (group->sgp->power != SCHED_POWER_SCALE) { 5241 printk(KERN_CONT " (cpu_power = %d)", 5242 group->sgp->power); 5243 } 5244 5245 group = group->next; 5246 } while (group != sd->groups); 5247 printk(KERN_CONT "\n"); 5248 5249 if (!cpumask_equal(sched_domain_span(sd), groupmask)) 5250 printk(KERN_ERR "ERROR: groups don't span domain->span\n"); 5251 5252 if (sd->parent && 5253 !cpumask_subset(groupmask, sched_domain_span(sd->parent))) 5254 printk(KERN_ERR "ERROR: parent span is not a superset " 5255 "of domain->span\n"); 5256 return 0; 5257} 5258 5259static void sched_domain_debug(struct sched_domain *sd, int cpu) 5260{ 5261 int level = 0; 5262 5263 if (!sched_debug_enabled) 5264 return; 5265 5266 if (!sd) { 5267 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); 5268 return; 5269 } 5270 5271 printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); 5272 5273 for (;;) { 5274 if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask)) 5275 break; 5276 level++; 5277 sd = sd->parent; 5278 if (!sd) 5279 break; 5280 } 5281} 5282#else /* !CONFIG_SCHED_DEBUG */ 5283# define sched_domain_debug(sd, cpu) do { } while (0) 5284static inline bool sched_debug(void) 5285{ 5286 return false; 5287} 5288#endif /* CONFIG_SCHED_DEBUG */ 5289 5290static int sd_degenerate(struct sched_domain *sd) 5291{ 5292 if (cpumask_weight(sched_domain_span(sd)) == 1) 5293 return 1; 5294 5295 /* Following flags need at least 2 groups */ 5296 if (sd->flags & (SD_LOAD_BALANCE | 5297 SD_BALANCE_NEWIDLE | 5298 SD_BALANCE_FORK | 5299 SD_BALANCE_EXEC | 5300 SD_SHARE_CPUPOWER | 5301 SD_SHARE_PKG_RESOURCES)) { 5302 if (sd->groups != sd->groups->next) 5303 return 0; 5304 } 5305 5306 /* Following flags don't use groups */ 5307 if (sd->flags & (SD_WAKE_AFFINE)) 5308 return 0; 5309 5310 return 1; 5311} 5312 5313static int 5314sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) 5315{ 5316 unsigned long cflags = sd->flags, pflags = parent->flags; 5317 5318 if (sd_degenerate(parent)) 5319 return 1; 5320 5321 if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent))) 5322 return 0; 5323 5324 /* Flags needing groups don't count if only 1 group in parent */ 5325 if (parent->groups == parent->groups->next) { 5326 pflags &= ~(SD_LOAD_BALANCE | 5327 SD_BALANCE_NEWIDLE | 5328 SD_BALANCE_FORK | 5329 SD_BALANCE_EXEC | 5330 SD_SHARE_CPUPOWER | 5331 SD_SHARE_PKG_RESOURCES | 5332 SD_PREFER_SIBLING); 5333 if (nr_node_ids == 1) 5334 pflags &= ~SD_SERIALIZE; 5335 } 5336 if (~cflags & pflags) 5337 return 0; 5338 5339 return 1; 5340} 5341 5342static void free_rootdomain(struct rcu_head *rcu) 5343{ 5344 struct root_domain *rd = container_of(rcu, struct root_domain, rcu); 5345 5346 cpupri_cleanup(&rd->cpupri); 5347 cpudl_cleanup(&rd->cpudl); 5348 free_cpumask_var(rd->dlo_mask); 5349 free_cpumask_var(rd->rto_mask); 5350 free_cpumask_var(rd->online); 5351 free_cpumask_var(rd->span); 5352 kfree(rd); 5353} 5354 5355static void rq_attach_root(struct rq *rq, struct root_domain *rd) 5356{ 5357 struct root_domain *old_rd = NULL; 5358 unsigned long flags; 5359 5360 raw_spin_lock_irqsave(&rq->lock, flags); 5361 5362 if (rq->rd) { 5363 old_rd = rq->rd; 5364 5365 if (cpumask_test_cpu(rq->cpu, old_rd->online)) 5366 set_rq_offline(rq); 5367 5368 cpumask_clear_cpu(rq->cpu, old_rd->span); 5369 5370 /* 5371 * If we dont want to free the old_rd yet then 5372 * set old_rd to NULL to skip the freeing later 5373 * in this function: 5374 */ 5375 if (!atomic_dec_and_test(&old_rd->refcount)) 5376 old_rd = NULL; 5377 } 5378 5379 atomic_inc(&rd->refcount); 5380 rq->rd = rd; 5381 5382 cpumask_set_cpu(rq->cpu, rd->span); 5383 if (cpumask_test_cpu(rq->cpu, cpu_active_mask)) 5384 set_rq_online(rq); 5385 5386 raw_spin_unlock_irqrestore(&rq->lock, flags); 5387 5388 if (old_rd) 5389 call_rcu_sched(&old_rd->rcu, free_rootdomain); 5390} 5391 5392static int init_rootdomain(struct root_domain *rd) 5393{ 5394 memset(rd, 0, sizeof(*rd)); 5395 5396 if (!alloc_cpumask_var(&rd->span, GFP_KERNEL)) 5397 goto out; 5398 if (!alloc_cpumask_var(&rd->online, GFP_KERNEL)) 5399 goto free_span; 5400 if (!alloc_cpumask_var(&rd->dlo_mask, GFP_KERNEL)) 5401 goto free_online; 5402 if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL)) 5403 goto free_dlo_mask; 5404 5405 init_dl_bw(&rd->dl_bw); 5406 if (cpudl_init(&rd->cpudl) != 0) 5407 goto free_dlo_mask; 5408 5409 if (cpupri_init(&rd->cpupri) != 0) 5410 goto free_rto_mask; 5411 return 0; 5412 5413free_rto_mask: 5414 free_cpumask_var(rd->rto_mask); 5415free_dlo_mask: 5416 free_cpumask_var(rd->dlo_mask); 5417free_online: 5418 free_cpumask_var(rd->online); 5419free_span: 5420 free_cpumask_var(rd->span); 5421out: 5422 return -ENOMEM; 5423} 5424 5425/* 5426 * By default the system creates a single root-domain with all cpus as 5427 * members (mimicking the global state we have today). 5428 */ 5429struct root_domain def_root_domain; 5430 5431static void init_defrootdomain(void) 5432{ 5433 init_rootdomain(&def_root_domain); 5434 5435 atomic_set(&def_root_domain.refcount, 1); 5436} 5437 5438static struct root_domain *alloc_rootdomain(void) 5439{ 5440 struct root_domain *rd; 5441 5442 rd = kmalloc(sizeof(*rd), GFP_KERNEL); 5443 if (!rd) 5444 return NULL; 5445 5446 if (init_rootdomain(rd) != 0) { 5447 kfree(rd); 5448 return NULL; 5449 } 5450 5451 return rd; 5452} 5453 5454static void free_sched_groups(struct sched_group *sg, int free_sgp) 5455{ 5456 struct sched_group *tmp, *first; 5457 5458 if (!sg) 5459 return; 5460 5461 first = sg; 5462 do { 5463 tmp = sg->next; 5464 5465 if (free_sgp && atomic_dec_and_test(&sg->sgp->ref)) 5466 kfree(sg->sgp); 5467 5468 kfree(sg); 5469 sg = tmp; 5470 } while (sg != first); 5471} 5472 5473static void free_sched_domain(struct rcu_head *rcu) 5474{ 5475 struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu); 5476 5477 /* 5478 * If its an overlapping domain it has private groups, iterate and 5479 * nuke them all. 5480 */ 5481 if (sd->flags & SD_OVERLAP) { 5482 free_sched_groups(sd->groups, 1); 5483 } else if (atomic_dec_and_test(&sd->groups->ref)) { 5484 kfree(sd->groups->sgp); 5485 kfree(sd->groups); 5486 } 5487 kfree(sd); 5488} 5489 5490static void destroy_sched_domain(struct sched_domain *sd, int cpu) 5491{ 5492 call_rcu(&sd->rcu, free_sched_domain); 5493} 5494 5495static void destroy_sched_domains(struct sched_domain *sd, int cpu) 5496{ 5497 for (; sd; sd = sd->parent) 5498 destroy_sched_domain(sd, cpu); 5499} 5500 5501/* 5502 * Keep a special pointer to the highest sched_domain that has 5503 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this 5504 * allows us to avoid some pointer chasing select_idle_sibling(). 5505 * 5506 * Also keep a unique ID per domain (we use the first cpu number in 5507 * the cpumask of the domain), this allows us to quickly tell if 5508 * two cpus are in the same cache domain, see cpus_share_cache(). 5509 */ 5510DEFINE_PER_CPU(struct sched_domain *, sd_llc); 5511DEFINE_PER_CPU(int, sd_llc_size); 5512DEFINE_PER_CPU(int, sd_llc_id); 5513DEFINE_PER_CPU(struct sched_domain *, sd_numa); 5514DEFINE_PER_CPU(struct sched_domain *, sd_busy); 5515DEFINE_PER_CPU(struct sched_domain *, sd_asym); 5516 5517static void update_top_cache_domain(int cpu) 5518{ 5519 struct sched_domain *sd; 5520 struct sched_domain *busy_sd = NULL; 5521 int id = cpu; 5522 int size = 1; 5523 5524 sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES); 5525 if (sd) { 5526 id = cpumask_first(sched_domain_span(sd)); 5527 size = cpumask_weight(sched_domain_span(sd)); 5528 busy_sd = sd->parent; /* sd_busy */ 5529 } 5530 rcu_assign_pointer(per_cpu(sd_busy, cpu), busy_sd); 5531 5532 rcu_assign_pointer(per_cpu(sd_llc, cpu), sd); 5533 per_cpu(sd_llc_size, cpu) = size; 5534 per_cpu(sd_llc_id, cpu) = id; 5535 5536 sd = lowest_flag_domain(cpu, SD_NUMA); 5537 rcu_assign_pointer(per_cpu(sd_numa, cpu), sd); 5538 5539 sd = highest_flag_domain(cpu, SD_ASYM_PACKING); 5540 rcu_assign_pointer(per_cpu(sd_asym, cpu), sd); 5541} 5542 5543/* 5544 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must 5545 * hold the hotplug lock. 5546 */ 5547static void 5548cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) 5549{ 5550 struct rq *rq = cpu_rq(cpu); 5551 struct sched_domain *tmp; 5552 5553 /* Remove the sched domains which do not contribute to scheduling. */ 5554 for (tmp = sd; tmp; ) { 5555 struct sched_domain *parent = tmp->parent; 5556 if (!parent) 5557 break; 5558 5559 if (sd_parent_degenerate(tmp, parent)) { 5560 tmp->parent = parent->parent; 5561 if (parent->parent) 5562 parent->parent->child = tmp; 5563 /* 5564 * Transfer SD_PREFER_SIBLING down in case of a 5565 * degenerate parent; the spans match for this 5566 * so the property transfers. 5567 */ 5568 if (parent->flags & SD_PREFER_SIBLING) 5569 tmp->flags |= SD_PREFER_SIBLING; 5570 destroy_sched_domain(parent, cpu); 5571 } else 5572 tmp = tmp->parent; 5573 } 5574 5575 if (sd && sd_degenerate(sd)) { 5576 tmp = sd; 5577 sd = sd->parent; 5578 destroy_sched_domain(tmp, cpu); 5579 if (sd) 5580 sd->child = NULL; 5581 } 5582 5583 sched_domain_debug(sd, cpu); 5584 5585 rq_attach_root(rq, rd); 5586 tmp = rq->sd; 5587 rcu_assign_pointer(rq->sd, sd); 5588 destroy_sched_domains(tmp, cpu); 5589 5590 update_top_cache_domain(cpu); 5591} 5592 5593/* cpus with isolated domains */ 5594static cpumask_var_t cpu_isolated_map; 5595 5596/* Setup the mask of cpus configured for isolated domains */ 5597static int __init isolated_cpu_setup(char *str) 5598{ 5599 alloc_bootmem_cpumask_var(&cpu_isolated_map); 5600 cpulist_parse(str, cpu_isolated_map); 5601 return 1; 5602} 5603 5604__setup("isolcpus=", isolated_cpu_setup); 5605 5606static const struct cpumask *cpu_cpu_mask(int cpu) 5607{ 5608 return cpumask_of_node(cpu_to_node(cpu)); 5609} 5610 5611struct sd_data { 5612 struct sched_domain **__percpu sd; 5613 struct sched_group **__percpu sg; 5614 struct sched_group_power **__percpu sgp; 5615}; 5616 5617struct s_data { 5618 struct sched_domain ** __percpu sd; 5619 struct root_domain *rd; 5620}; 5621 5622enum s_alloc { 5623 sa_rootdomain, 5624 sa_sd, 5625 sa_sd_storage, 5626 sa_none, 5627}; 5628 5629struct sched_domain_topology_level; 5630 5631typedef struct sched_domain *(*sched_domain_init_f)(struct sched_domain_topology_level *tl, int cpu); 5632typedef const struct cpumask *(*sched_domain_mask_f)(int cpu); 5633 5634#define SDTL_OVERLAP 0x01 5635 5636struct sched_domain_topology_level { 5637 sched_domain_init_f init; 5638 sched_domain_mask_f mask; 5639 int flags; 5640 int numa_level; 5641 struct sd_data data; 5642}; 5643 5644/* 5645 * Build an iteration mask that can exclude certain CPUs from the upwards 5646 * domain traversal. 5647 * 5648 * Asymmetric node setups can result in situations where the domain tree is of 5649 * unequal depth, make sure to skip domains that already cover the entire 5650 * range. 5651 * 5652 * In that case build_sched_domains() will have terminated the iteration early 5653 * and our sibling sd spans will be empty. Domains should always include the 5654 * cpu they're built on, so check that. 5655 * 5656 */ 5657static void build_group_mask(struct sched_domain *sd, struct sched_group *sg) 5658{ 5659 const struct cpumask *span = sched_domain_span(sd); 5660 struct sd_data *sdd = sd->private; 5661 struct sched_domain *sibling; 5662 int i; 5663 5664 for_each_cpu(i, span) { 5665 sibling = *per_cpu_ptr(sdd->sd, i); 5666 if (!cpumask_test_cpu(i, sched_domain_span(sibling))) 5667 continue; 5668 5669 cpumask_set_cpu(i, sched_group_mask(sg)); 5670 } 5671} 5672 5673/* 5674 * Return the canonical balance cpu for this group, this is the first cpu 5675 * of this group that's also in the iteration mask. 5676 */ 5677int group_balance_cpu(struct sched_group *sg) 5678{ 5679 return cpumask_first_and(sched_group_cpus(sg), sched_group_mask(sg)); 5680} 5681 5682static int 5683build_overlap_sched_groups(struct sched_domain *sd, int cpu) 5684{ 5685 struct sched_group *first = NULL, *last = NULL, *groups = NULL, *sg; 5686 const struct cpumask *span = sched_domain_span(sd); 5687 struct cpumask *covered = sched_domains_tmpmask; 5688 struct sd_data *sdd = sd->private; 5689 struct sched_domain *child; 5690 int i; 5691 5692 cpumask_clear(covered); 5693 5694 for_each_cpu(i, span) { 5695 struct cpumask *sg_span; 5696 5697 if (cpumask_test_cpu(i, covered)) 5698 continue; 5699 5700 child = *per_cpu_ptr(sdd->sd, i); 5701 5702 /* See the comment near build_group_mask(). */ 5703 if (!cpumask_test_cpu(i, sched_domain_span(child))) 5704 continue; 5705 5706 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), 5707 GFP_KERNEL, cpu_to_node(cpu)); 5708 5709 if (!sg) 5710 goto fail; 5711 5712 sg_span = sched_group_cpus(sg); 5713 if (child->child) { 5714 child = child->child; 5715 cpumask_copy(sg_span, sched_domain_span(child)); 5716 } else 5717 cpumask_set_cpu(i, sg_span); 5718 5719 cpumask_or(covered, covered, sg_span); 5720 5721 sg->sgp = *per_cpu_ptr(sdd->sgp, i); 5722 if (atomic_inc_return(&sg->sgp->ref) == 1) 5723 build_group_mask(sd, sg); 5724 5725 /* 5726 * Initialize sgp->power such that even if we mess up the 5727 * domains and no possible iteration will get us here, we won't 5728 * die on a /0 trap. 5729 */ 5730 sg->sgp->power = SCHED_POWER_SCALE * cpumask_weight(sg_span); 5731 sg->sgp->power_orig = sg->sgp->power; 5732 5733 /* 5734 * Make sure the first group of this domain contains the 5735 * canonical balance cpu. Otherwise the sched_domain iteration 5736 * breaks. See update_sg_lb_stats(). 5737 */ 5738 if ((!groups && cpumask_test_cpu(cpu, sg_span)) || 5739 group_balance_cpu(sg) == cpu) 5740 groups = sg; 5741 5742 if (!first) 5743 first = sg; 5744 if (last) 5745 last->next = sg; 5746 last = sg; 5747 last->next = first; 5748 } 5749 sd->groups = groups; 5750 5751 return 0; 5752 5753fail: 5754 free_sched_groups(first, 0); 5755 5756 return -ENOMEM; 5757} 5758 5759static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg) 5760{ 5761 struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu); 5762 struct sched_domain *child = sd->child; 5763 5764 if (child) 5765 cpu = cpumask_first(sched_domain_span(child)); 5766 5767 if (sg) { 5768 *sg = *per_cpu_ptr(sdd->sg, cpu); 5769 (*sg)->sgp = *per_cpu_ptr(sdd->sgp, cpu); 5770 atomic_set(&(*sg)->sgp->ref, 1); /* for claim_allocations */ 5771 } 5772 5773 return cpu; 5774} 5775 5776/* 5777 * build_sched_groups will build a circular linked list of the groups 5778 * covered by the given span, and will set each group's ->cpumask correctly, 5779 * and ->cpu_power to 0. 5780 * 5781 * Assumes the sched_domain tree is fully constructed 5782 */ 5783static int 5784build_sched_groups(struct sched_domain *sd, int cpu) 5785{ 5786 struct sched_group *first = NULL, *last = NULL; 5787 struct sd_data *sdd = sd->private; 5788 const struct cpumask *span = sched_domain_span(sd); 5789 struct cpumask *covered; 5790 int i; 5791 5792 get_group(cpu, sdd, &sd->groups); 5793 atomic_inc(&sd->groups->ref); 5794 5795 if (cpu != cpumask_first(span)) 5796 return 0; 5797 5798 lockdep_assert_held(&sched_domains_mutex); 5799 covered = sched_domains_tmpmask; 5800 5801 cpumask_clear(covered); 5802 5803 for_each_cpu(i, span) { 5804 struct sched_group *sg; 5805 int group, j; 5806 5807 if (cpumask_test_cpu(i, covered)) 5808 continue; 5809 5810 group = get_group(i, sdd, &sg); 5811 cpumask_clear(sched_group_cpus(sg)); 5812 sg->sgp->power = 0; 5813 cpumask_setall(sched_group_mask(sg)); 5814 5815 for_each_cpu(j, span) { 5816 if (get_group(j, sdd, NULL) != group) 5817 continue; 5818 5819 cpumask_set_cpu(j, covered); 5820 cpumask_set_cpu(j, sched_group_cpus(sg)); 5821 } 5822 5823 if (!first) 5824 first = sg; 5825 if (last) 5826 last->next = sg; 5827 last = sg; 5828 } 5829 last->next = first; 5830 5831 return 0; 5832} 5833 5834/* 5835 * Initialize sched groups cpu_power. 5836 * 5837 * cpu_power indicates the capacity of sched group, which is used while 5838 * distributing the load between different sched groups in a sched domain. 5839 * Typically cpu_power for all the groups in a sched domain will be same unless 5840 * there are asymmetries in the topology. If there are asymmetries, group 5841 * having more cpu_power will pickup more load compared to the group having 5842 * less cpu_power. 5843 */ 5844static void init_sched_groups_power(int cpu, struct sched_domain *sd) 5845{ 5846 struct sched_group *sg = sd->groups; 5847 5848 WARN_ON(!sg); 5849 5850 do { 5851 sg->group_weight = cpumask_weight(sched_group_cpus(sg)); 5852 sg = sg->next; 5853 } while (sg != sd->groups); 5854 5855 if (cpu != group_balance_cpu(sg)) 5856 return; 5857 5858 update_group_power(sd, cpu); 5859 atomic_set(&sg->sgp->nr_busy_cpus, sg->group_weight); 5860} 5861 5862int __weak arch_sd_sibling_asym_packing(void) 5863{ 5864 return 0*SD_ASYM_PACKING; 5865} 5866 5867/* 5868 * Initializers for schedule domains 5869 * Non-inlined to reduce accumulated stack pressure in build_sched_domains() 5870 */ 5871 5872#ifdef CONFIG_SCHED_DEBUG 5873# define SD_INIT_NAME(sd, type) sd->name = #type 5874#else 5875# define SD_INIT_NAME(sd, type) do { } while (0) 5876#endif 5877 5878#define SD_INIT_FUNC(type) \ 5879static noinline struct sched_domain * \ 5880sd_init_##type(struct sched_domain_topology_level *tl, int cpu) \ 5881{ \ 5882 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); \ 5883 *sd = SD_##type##_INIT; \ 5884 SD_INIT_NAME(sd, type); \ 5885 sd->private = &tl->data; \ 5886 return sd; \ 5887} 5888 5889SD_INIT_FUNC(CPU) 5890#ifdef CONFIG_SCHED_SMT 5891 SD_INIT_FUNC(SIBLING) 5892#endif 5893#ifdef CONFIG_SCHED_MC 5894 SD_INIT_FUNC(MC) 5895#endif 5896#ifdef CONFIG_SCHED_BOOK 5897 SD_INIT_FUNC(BOOK) 5898#endif 5899 5900static int default_relax_domain_level = -1; 5901int sched_domain_level_max; 5902 5903static int __init setup_relax_domain_level(char *str) 5904{ 5905 if (kstrtoint(str, 0, &default_relax_domain_level)) 5906 pr_warn("Unable to set relax_domain_level\n"); 5907 5908 return 1; 5909} 5910__setup("relax_domain_level=", setup_relax_domain_level); 5911 5912static void set_domain_attribute(struct sched_domain *sd, 5913 struct sched_domain_attr *attr) 5914{ 5915 int request; 5916 5917 if (!attr || attr->relax_domain_level < 0) { 5918 if (default_relax_domain_level < 0) 5919 return; 5920 else 5921 request = default_relax_domain_level; 5922 } else 5923 request = attr->relax_domain_level; 5924 if (request < sd->level) { 5925 /* turn off idle balance on this domain */ 5926 sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); 5927 } else { 5928 /* turn on idle balance on this domain */ 5929 sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); 5930 } 5931} 5932 5933static void __sdt_free(const struct cpumask *cpu_map); 5934static int __sdt_alloc(const struct cpumask *cpu_map); 5935 5936static void __free_domain_allocs(struct s_data *d, enum s_alloc what, 5937 const struct cpumask *cpu_map) 5938{ 5939 switch (what) { 5940 case sa_rootdomain: 5941 if (!atomic_read(&d->rd->refcount)) 5942 free_rootdomain(&d->rd->rcu); /* fall through */ 5943 case sa_sd: 5944 free_percpu(d->sd); /* fall through */ 5945 case sa_sd_storage: 5946 __sdt_free(cpu_map); /* fall through */ 5947 case sa_none: 5948 break; 5949 } 5950} 5951 5952static enum s_alloc __visit_domain_allocation_hell(struct s_data *d, 5953 const struct cpumask *cpu_map) 5954{ 5955 memset(d, 0, sizeof(*d)); 5956 5957 if (__sdt_alloc(cpu_map)) 5958 return sa_sd_storage; 5959 d->sd = alloc_percpu(struct sched_domain *); 5960 if (!d->sd) 5961 return sa_sd_storage; 5962 d->rd = alloc_rootdomain(); 5963 if (!d->rd) 5964 return sa_sd; 5965 return sa_rootdomain; 5966} 5967 5968/* 5969 * NULL the sd_data elements we've used to build the sched_domain and 5970 * sched_group structure so that the subsequent __free_domain_allocs() 5971 * will not free the data we're using. 5972 */ 5973static void claim_allocations(int cpu, struct sched_domain *sd) 5974{ 5975 struct sd_data *sdd = sd->private; 5976 5977 WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd); 5978 *per_cpu_ptr(sdd->sd, cpu) = NULL; 5979 5980 if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref)) 5981 *per_cpu_ptr(sdd->sg, cpu) = NULL; 5982 5983 if (atomic_read(&(*per_cpu_ptr(sdd->sgp, cpu))->ref)) 5984 *per_cpu_ptr(sdd->sgp, cpu) = NULL; 5985} 5986 5987#ifdef CONFIG_SCHED_SMT 5988static const struct cpumask *cpu_smt_mask(int cpu) 5989{ 5990 return topology_thread_cpumask(cpu); 5991} 5992#endif 5993 5994/* 5995 * Topology list, bottom-up. 5996 */ 5997static struct sched_domain_topology_level default_topology[] = { 5998#ifdef CONFIG_SCHED_SMT 5999 { sd_init_SIBLING, cpu_smt_mask, }, 6000#endif 6001#ifdef CONFIG_SCHED_MC 6002 { sd_init_MC, cpu_coregroup_mask, }, 6003#endif 6004#ifdef CONFIG_SCHED_BOOK 6005 { sd_init_BOOK, cpu_book_mask, }, 6006#endif 6007 { sd_init_CPU, cpu_cpu_mask, }, 6008 { NULL, }, 6009}; 6010 6011static struct sched_domain_topology_level *sched_domain_topology = default_topology; 6012 6013#define for_each_sd_topology(tl) \ 6014 for (tl = sched_domain_topology; tl->init; tl++) 6015 6016#ifdef CONFIG_NUMA 6017 6018static int sched_domains_numa_levels; 6019static int *sched_domains_numa_distance; 6020static struct cpumask ***sched_domains_numa_masks; 6021static int sched_domains_curr_level; 6022 6023static inline int sd_local_flags(int level) 6024{ 6025 if (sched_domains_numa_distance[level] > RECLAIM_DISTANCE) 6026 return 0; 6027 6028 return SD_BALANCE_EXEC | SD_BALANCE_FORK | SD_WAKE_AFFINE; 6029} 6030 6031static struct sched_domain * 6032sd_numa_init(struct sched_domain_topology_level *tl, int cpu) 6033{ 6034 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); 6035 int level = tl->numa_level; 6036 int sd_weight = cpumask_weight( 6037 sched_domains_numa_masks[level][cpu_to_node(cpu)]); 6038 6039 *sd = (struct sched_domain){ 6040 .min_interval = sd_weight, 6041 .max_interval = 2*sd_weight, 6042 .busy_factor = 32, 6043 .imbalance_pct = 125, 6044 .cache_nice_tries = 2, 6045 .busy_idx = 3, 6046 .idle_idx = 2, 6047 .newidle_idx = 0, 6048 .wake_idx = 0, 6049 .forkexec_idx = 0, 6050 6051 .flags = 1*SD_LOAD_BALANCE 6052 | 1*SD_BALANCE_NEWIDLE 6053 | 0*SD_BALANCE_EXEC 6054 | 0*SD_BALANCE_FORK 6055 | 0*SD_BALANCE_WAKE 6056 | 0*SD_WAKE_AFFINE 6057 | 0*SD_SHARE_CPUPOWER 6058 | 0*SD_SHARE_PKG_RESOURCES 6059 | 1*SD_SERIALIZE 6060 | 0*SD_PREFER_SIBLING 6061 | 1*SD_NUMA 6062 | sd_local_flags(level) 6063 , 6064 .last_balance = jiffies, 6065 .balance_interval = sd_weight, 6066 }; 6067 SD_INIT_NAME(sd, NUMA); 6068 sd->private = &tl->data; 6069 6070 /* 6071 * Ugly hack to pass state to sd_numa_mask()... 6072 */ 6073 sched_domains_curr_level = tl->numa_level; 6074 6075 return sd; 6076} 6077 6078static const struct cpumask *sd_numa_mask(int cpu) 6079{ 6080 return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)]; 6081} 6082 6083static void sched_numa_warn(const char *str) 6084{ 6085 static int done = false; 6086 int i,j; 6087 6088 if (done) 6089 return; 6090 6091 done = true; 6092 6093 printk(KERN_WARNING "ERROR: %s\n\n", str); 6094 6095 for (i = 0; i < nr_node_ids; i++) { 6096 printk(KERN_WARNING " "); 6097 for (j = 0; j < nr_node_ids; j++) 6098 printk(KERN_CONT "%02d ", node_distance(i,j)); 6099 printk(KERN_CONT "\n"); 6100 } 6101 printk(KERN_WARNING "\n"); 6102} 6103 6104static bool find_numa_distance(int distance) 6105{ 6106 int i; 6107 6108 if (distance == node_distance(0, 0)) 6109 return true; 6110 6111 for (i = 0; i < sched_domains_numa_levels; i++) { 6112 if (sched_domains_numa_distance[i] == distance) 6113 return true; 6114 } 6115 6116 return false; 6117} 6118 6119static void sched_init_numa(void) 6120{ 6121 int next_distance, curr_distance = node_distance(0, 0); 6122 struct sched_domain_topology_level *tl; 6123 int level = 0; 6124 int i, j, k; 6125 6126 sched_domains_numa_distance = kzalloc(sizeof(int) * nr_node_ids, GFP_KERNEL); 6127 if (!sched_domains_numa_distance) 6128 return; 6129 6130 /* 6131 * O(nr_nodes^2) deduplicating selection sort -- in order to find the 6132 * unique distances in the node_distance() table. 6133 * 6134 * Assumes node_distance(0,j) includes all distances in 6135 * node_distance(i,j) in order to avoid cubic time. 6136 */ 6137 next_distance = curr_distance; 6138 for (i = 0; i < nr_node_ids; i++) { 6139 for (j = 0; j < nr_node_ids; j++) { 6140 for (k = 0; k < nr_node_ids; k++) { 6141 int distance = node_distance(i, k); 6142 6143 if (distance > curr_distance && 6144 (distance < next_distance || 6145 next_distance == curr_distance)) 6146 next_distance = distance; 6147 6148 /* 6149 * While not a strong assumption it would be nice to know 6150 * about cases where if node A is connected to B, B is not 6151 * equally connected to A. 6152 */ 6153 if (sched_debug() && node_distance(k, i) != distance) 6154 sched_numa_warn("Node-distance not symmetric"); 6155 6156 if (sched_debug() && i && !find_numa_distance(distance)) 6157 sched_numa_warn("Node-0 not representative"); 6158 } 6159 if (next_distance != curr_distance) { 6160 sched_domains_numa_distance[level++] = next_distance; 6161 sched_domains_numa_levels = level; 6162 curr_distance = next_distance; 6163 } else break; 6164 } 6165 6166 /* 6167 * In case of sched_debug() we verify the above assumption. 6168 */ 6169 if (!sched_debug()) 6170 break; 6171 } 6172 /* 6173 * 'level' contains the number of unique distances, excluding the 6174 * identity distance node_distance(i,i). 6175 * 6176 * The sched_domains_numa_distance[] array includes the actual distance 6177 * numbers. 6178 */ 6179 6180 /* 6181 * Here, we should temporarily reset sched_domains_numa_levels to 0. 6182 * If it fails to allocate memory for array sched_domains_numa_masks[][], 6183 * the array will contain less then 'level' members. This could be 6184 * dangerous when we use it to iterate array sched_domains_numa_masks[][] 6185 * in other functions. 6186 * 6187 * We reset it to 'level' at the end of this function. 6188 */ 6189 sched_domains_numa_levels = 0; 6190 6191 sched_domains_numa_masks = kzalloc(sizeof(void *) * level, GFP_KERNEL); 6192 if (!sched_domains_numa_masks) 6193 return; 6194 6195 /* 6196 * Now for each level, construct a mask per node which contains all 6197 * cpus of nodes that are that many hops away from us. 6198 */ 6199 for (i = 0; i < level; i++) { 6200 sched_domains_numa_masks[i] = 6201 kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL); 6202 if (!sched_domains_numa_masks[i]) 6203 return; 6204 6205 for (j = 0; j < nr_node_ids; j++) { 6206 struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL); 6207 if (!mask) 6208 return; 6209 6210 sched_domains_numa_masks[i][j] = mask; 6211 6212 for (k = 0; k < nr_node_ids; k++) { 6213 if (node_distance(j, k) > sched_domains_numa_distance[i]) 6214 continue; 6215 6216 cpumask_or(mask, mask, cpumask_of_node(k)); 6217 } 6218 } 6219 } 6220 6221 tl = kzalloc((ARRAY_SIZE(default_topology) + level) * 6222 sizeof(struct sched_domain_topology_level), GFP_KERNEL); 6223 if (!tl) 6224 return; 6225 6226 /* 6227 * Copy the default topology bits.. 6228 */ 6229 for (i = 0; default_topology[i].init; i++) 6230 tl[i] = default_topology[i]; 6231 6232 /* 6233 * .. and append 'j' levels of NUMA goodness. 6234 */ 6235 for (j = 0; j < level; i++, j++) { 6236 tl[i] = (struct sched_domain_topology_level){ 6237 .init = sd_numa_init, 6238 .mask = sd_numa_mask, 6239 .flags = SDTL_OVERLAP, 6240 .numa_level = j, 6241 }; 6242 } 6243 6244 sched_domain_topology = tl; 6245 6246 sched_domains_numa_levels = level; 6247} 6248 6249static void sched_domains_numa_masks_set(int cpu) 6250{ 6251 int i, j; 6252 int node = cpu_to_node(cpu); 6253 6254 for (i = 0; i < sched_domains_numa_levels; i++) { 6255 for (j = 0; j < nr_node_ids; j++) { 6256 if (node_distance(j, node) <= sched_domains_numa_distance[i]) 6257 cpumask_set_cpu(cpu, sched_domains_numa_masks[i][j]); 6258 } 6259 } 6260} 6261 6262static void sched_domains_numa_masks_clear(int cpu) 6263{ 6264 int i, j; 6265 for (i = 0; i < sched_domains_numa_levels; i++) { 6266 for (j = 0; j < nr_node_ids; j++) 6267 cpumask_clear_cpu(cpu, sched_domains_numa_masks[i][j]); 6268 } 6269} 6270 6271/* 6272 * Update sched_domains_numa_masks[level][node] array when new cpus 6273 * are onlined. 6274 */ 6275static int sched_domains_numa_masks_update(struct notifier_block *nfb, 6276 unsigned long action, 6277 void *hcpu) 6278{ 6279 int cpu = (long)hcpu; 6280 6281 switch (action & ~CPU_TASKS_FROZEN) { 6282 case CPU_ONLINE: 6283 sched_domains_numa_masks_set(cpu); 6284 break; 6285 6286 case CPU_DEAD: 6287 sched_domains_numa_masks_clear(cpu); 6288 break; 6289 6290 default: 6291 return NOTIFY_DONE; 6292 } 6293 6294 return NOTIFY_OK; 6295} 6296#else 6297static inline void sched_init_numa(void) 6298{ 6299} 6300 6301static int sched_domains_numa_masks_update(struct notifier_block *nfb, 6302 unsigned long action, 6303 void *hcpu) 6304{ 6305 return 0; 6306} 6307#endif /* CONFIG_NUMA */ 6308 6309static int __sdt_alloc(const struct cpumask *cpu_map) 6310{ 6311 struct sched_domain_topology_level *tl; 6312 int j; 6313 6314 for_each_sd_topology(tl) { 6315 struct sd_data *sdd = &tl->data; 6316 6317 sdd->sd = alloc_percpu(struct sched_domain *); 6318 if (!sdd->sd) 6319 return -ENOMEM; 6320 6321 sdd->sg = alloc_percpu(struct sched_group *); 6322 if (!sdd->sg) 6323 return -ENOMEM; 6324 6325 sdd->sgp = alloc_percpu(struct sched_group_power *); 6326 if (!sdd->sgp) 6327 return -ENOMEM; 6328 6329 for_each_cpu(j, cpu_map) { 6330 struct sched_domain *sd; 6331 struct sched_group *sg; 6332 struct sched_group_power *sgp; 6333 6334 sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(), 6335 GFP_KERNEL, cpu_to_node(j)); 6336 if (!sd) 6337 return -ENOMEM; 6338 6339 *per_cpu_ptr(sdd->sd, j) = sd; 6340 6341 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), 6342 GFP_KERNEL, cpu_to_node(j)); 6343 if (!sg) 6344 return -ENOMEM; 6345 6346 sg->next = sg; 6347 6348 *per_cpu_ptr(sdd->sg, j) = sg; 6349 6350 sgp = kzalloc_node(sizeof(struct sched_group_power) + cpumask_size(), 6351 GFP_KERNEL, cpu_to_node(j)); 6352 if (!sgp) 6353 return -ENOMEM; 6354 6355 *per_cpu_ptr(sdd->sgp, j) = sgp; 6356 } 6357 } 6358 6359 return 0; 6360} 6361 6362static void __sdt_free(const struct cpumask *cpu_map) 6363{ 6364 struct sched_domain_topology_level *tl; 6365 int j; 6366 6367 for_each_sd_topology(tl) { 6368 struct sd_data *sdd = &tl->data; 6369 6370 for_each_cpu(j, cpu_map) { 6371 struct sched_domain *sd; 6372 6373 if (sdd->sd) { 6374 sd = *per_cpu_ptr(sdd->sd, j); 6375 if (sd && (sd->flags & SD_OVERLAP)) 6376 free_sched_groups(sd->groups, 0); 6377 kfree(*per_cpu_ptr(sdd->sd, j)); 6378 } 6379 6380 if (sdd->sg) 6381 kfree(*per_cpu_ptr(sdd->sg, j)); 6382 if (sdd->sgp) 6383 kfree(*per_cpu_ptr(sdd->sgp, j)); 6384 } 6385 free_percpu(sdd->sd); 6386 sdd->sd = NULL; 6387 free_percpu(sdd->sg); 6388 sdd->sg = NULL; 6389 free_percpu(sdd->sgp); 6390 sdd->sgp = NULL; 6391 } 6392} 6393 6394struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl, 6395 const struct cpumask *cpu_map, struct sched_domain_attr *attr, 6396 struct sched_domain *child, int cpu) 6397{ 6398 struct sched_domain *sd = tl->init(tl, cpu); 6399 if (!sd) 6400 return child; 6401 6402 cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu)); 6403 if (child) { 6404 sd->level = child->level + 1; 6405 sched_domain_level_max = max(sched_domain_level_max, sd->level); 6406 child->parent = sd; 6407 sd->child = child; 6408 } 6409 set_domain_attribute(sd, attr); 6410 6411 return sd; 6412} 6413 6414/* 6415 * Build sched domains for a given set of cpus and attach the sched domains 6416 * to the individual cpus 6417 */ 6418static int build_sched_domains(const struct cpumask *cpu_map, 6419 struct sched_domain_attr *attr) 6420{ 6421 enum s_alloc alloc_state; 6422 struct sched_domain *sd; 6423 struct s_data d; 6424 int i, ret = -ENOMEM; 6425 6426 alloc_state = __visit_domain_allocation_hell(&d, cpu_map); 6427 if (alloc_state != sa_rootdomain) 6428 goto error; 6429 6430 /* Set up domains for cpus specified by the cpu_map. */ 6431 for_each_cpu(i, cpu_map) { 6432 struct sched_domain_topology_level *tl; 6433 6434 sd = NULL; 6435 for_each_sd_topology(tl) { 6436 sd = build_sched_domain(tl, cpu_map, attr, sd, i); 6437 if (tl == sched_domain_topology) 6438 *per_cpu_ptr(d.sd, i) = sd; 6439 if (tl->flags & SDTL_OVERLAP || sched_feat(FORCE_SD_OVERLAP)) 6440 sd->flags |= SD_OVERLAP; 6441 if (cpumask_equal(cpu_map, sched_domain_span(sd))) 6442 break; 6443 } 6444 } 6445 6446 /* Build the groups for the domains */ 6447 for_each_cpu(i, cpu_map) { 6448 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { 6449 sd->span_weight = cpumask_weight(sched_domain_span(sd)); 6450 if (sd->flags & SD_OVERLAP) { 6451 if (build_overlap_sched_groups(sd, i)) 6452 goto error; 6453 } else { 6454 if (build_sched_groups(sd, i)) 6455 goto error; 6456 } 6457 } 6458 } 6459 6460 /* Calculate CPU power for physical packages and nodes */ 6461 for (i = nr_cpumask_bits-1; i >= 0; i--) { 6462 if (!cpumask_test_cpu(i, cpu_map)) 6463 continue; 6464 6465 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { 6466 claim_allocations(i, sd); 6467 init_sched_groups_power(i, sd); 6468 } 6469 } 6470 6471 /* Attach the domains */ 6472 rcu_read_lock(); 6473 for_each_cpu(i, cpu_map) { 6474 sd = *per_cpu_ptr(d.sd, i); 6475 cpu_attach_domain(sd, d.rd, i); 6476 } 6477 rcu_read_unlock(); 6478 6479 ret = 0; 6480error: 6481 __free_domain_allocs(&d, alloc_state, cpu_map); 6482 return ret; 6483} 6484 6485static cpumask_var_t *doms_cur; /* current sched domains */ 6486static int ndoms_cur; /* number of sched domains in 'doms_cur' */ 6487static struct sched_domain_attr *dattr_cur; 6488 /* attribues of custom domains in 'doms_cur' */ 6489 6490/* 6491 * Special case: If a kmalloc of a doms_cur partition (array of 6492 * cpumask) fails, then fallback to a single sched domain, 6493 * as determined by the single cpumask fallback_doms. 6494 */ 6495static cpumask_var_t fallback_doms; 6496 6497/* 6498 * arch_update_cpu_topology lets virtualized architectures update the 6499 * cpu core maps. It is supposed to return 1 if the topology changed 6500 * or 0 if it stayed the same. 6501 */ 6502int __attribute__((weak)) arch_update_cpu_topology(void) 6503{ 6504 return 0; 6505} 6506 6507cpumask_var_t *alloc_sched_domains(unsigned int ndoms) 6508{ 6509 int i; 6510 cpumask_var_t *doms; 6511 6512 doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL); 6513 if (!doms) 6514 return NULL; 6515 for (i = 0; i < ndoms; i++) { 6516 if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) { 6517 free_sched_domains(doms, i); 6518 return NULL; 6519 } 6520 } 6521 return doms; 6522} 6523 6524void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms) 6525{ 6526 unsigned int i; 6527 for (i = 0; i < ndoms; i++) 6528 free_cpumask_var(doms[i]); 6529 kfree(doms); 6530} 6531 6532/* 6533 * Set up scheduler domains and groups. Callers must hold the hotplug lock. 6534 * For now this just excludes isolated cpus, but could be used to 6535 * exclude other special cases in the future. 6536 */ 6537static int init_sched_domains(const struct cpumask *cpu_map) 6538{ 6539 int err; 6540 6541 arch_update_cpu_topology(); 6542 ndoms_cur = 1; 6543 doms_cur = alloc_sched_domains(ndoms_cur); 6544 if (!doms_cur) 6545 doms_cur = &fallback_doms; 6546 cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map); 6547 err = build_sched_domains(doms_cur[0], NULL); 6548 register_sched_domain_sysctl(); 6549 6550 return err; 6551} 6552 6553/* 6554 * Detach sched domains from a group of cpus specified in cpu_map 6555 * These cpus will now be attached to the NULL domain 6556 */ 6557static void detach_destroy_domains(const struct cpumask *cpu_map) 6558{ 6559 int i; 6560 6561 rcu_read_lock(); 6562 for_each_cpu(i, cpu_map) 6563 cpu_attach_domain(NULL, &def_root_domain, i); 6564 rcu_read_unlock(); 6565} 6566 6567/* handle null as "default" */ 6568static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur, 6569 struct sched_domain_attr *new, int idx_new) 6570{ 6571 struct sched_domain_attr tmp; 6572 6573 /* fast path */ 6574 if (!new && !cur) 6575 return 1; 6576 6577 tmp = SD_ATTR_INIT; 6578 return !memcmp(cur ? (cur + idx_cur) : &tmp, 6579 new ? (new + idx_new) : &tmp, 6580 sizeof(struct sched_domain_attr)); 6581} 6582 6583/* 6584 * Partition sched domains as specified by the 'ndoms_new' 6585 * cpumasks in the array doms_new[] of cpumasks. This compares 6586 * doms_new[] to the current sched domain partitioning, doms_cur[]. 6587 * It destroys each deleted domain and builds each new domain. 6588 * 6589 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'. 6590 * The masks don't intersect (don't overlap.) We should setup one 6591 * sched domain for each mask. CPUs not in any of the cpumasks will 6592 * not be load balanced. If the same cpumask appears both in the 6593 * current 'doms_cur' domains and in the new 'doms_new', we can leave 6594 * it as it is. 6595 * 6596 * The passed in 'doms_new' should be allocated using 6597 * alloc_sched_domains. This routine takes ownership of it and will 6598 * free_sched_domains it when done with it. If the caller failed the 6599 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1, 6600 * and partition_sched_domains() will fallback to the single partition 6601 * 'fallback_doms', it also forces the domains to be rebuilt. 6602 * 6603 * If doms_new == NULL it will be replaced with cpu_online_mask. 6604 * ndoms_new == 0 is a special case for destroying existing domains, 6605 * and it will not create the default domain. 6606 * 6607 * Call with hotplug lock held 6608 */ 6609void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[], 6610 struct sched_domain_attr *dattr_new) 6611{ 6612 int i, j, n; 6613 int new_topology; 6614 6615 mutex_lock(&sched_domains_mutex); 6616 6617 /* always unregister in case we don't destroy any domains */ 6618 unregister_sched_domain_sysctl(); 6619 6620 /* Let architecture update cpu core mappings. */ 6621 new_topology = arch_update_cpu_topology(); 6622 6623 n = doms_new ? ndoms_new : 0; 6624 6625 /* Destroy deleted domains */ 6626 for (i = 0; i < ndoms_cur; i++) { 6627 for (j = 0; j < n && !new_topology; j++) { 6628 if (cpumask_equal(doms_cur[i], doms_new[j]) 6629 && dattrs_equal(dattr_cur, i, dattr_new, j)) 6630 goto match1; 6631 } 6632 /* no match - a current sched domain not in new doms_new[] */ 6633 detach_destroy_domains(doms_cur[i]); 6634match1: 6635 ; 6636 } 6637 6638 n = ndoms_cur; 6639 if (doms_new == NULL) { 6640 n = 0; 6641 doms_new = &fallback_doms; 6642 cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map); 6643 WARN_ON_ONCE(dattr_new); 6644 } 6645 6646 /* Build new domains */ 6647 for (i = 0; i < ndoms_new; i++) { 6648 for (j = 0; j < n && !new_topology; j++) { 6649 if (cpumask_equal(doms_new[i], doms_cur[j]) 6650 && dattrs_equal(dattr_new, i, dattr_cur, j)) 6651 goto match2; 6652 } 6653 /* no match - add a new doms_new */ 6654 build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL); 6655match2: 6656 ; 6657 } 6658 6659 /* Remember the new sched domains */ 6660 if (doms_cur != &fallback_doms) 6661 free_sched_domains(doms_cur, ndoms_cur); 6662 kfree(dattr_cur); /* kfree(NULL) is safe */ 6663 doms_cur = doms_new; 6664 dattr_cur = dattr_new; 6665 ndoms_cur = ndoms_new; 6666 6667 register_sched_domain_sysctl(); 6668 6669 mutex_unlock(&sched_domains_mutex); 6670} 6671 6672static int num_cpus_frozen; /* used to mark begin/end of suspend/resume */ 6673 6674/* 6675 * Update cpusets according to cpu_active mask. If cpusets are 6676 * disabled, cpuset_update_active_cpus() becomes a simple wrapper 6677 * around partition_sched_domains(). 6678 * 6679 * If we come here as part of a suspend/resume, don't touch cpusets because we 6680 * want to restore it back to its original state upon resume anyway. 6681 */ 6682static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action, 6683 void *hcpu) 6684{ 6685 switch (action) { 6686 case CPU_ONLINE_FROZEN: 6687 case CPU_DOWN_FAILED_FROZEN: 6688 6689 /* 6690 * num_cpus_frozen tracks how many CPUs are involved in suspend 6691 * resume sequence. As long as this is not the last online 6692 * operation in the resume sequence, just build a single sched 6693 * domain, ignoring cpusets. 6694 */ 6695 num_cpus_frozen--; 6696 if (likely(num_cpus_frozen)) { 6697 partition_sched_domains(1, NULL, NULL); 6698 break; 6699 } 6700 6701 /* 6702 * This is the last CPU online operation. So fall through and 6703 * restore the original sched domains by considering the 6704 * cpuset configurations. 6705 */ 6706 6707 case CPU_ONLINE: 6708 case CPU_DOWN_FAILED: 6709 cpuset_update_active_cpus(true); 6710 break; 6711 default: 6712 return NOTIFY_DONE; 6713 } 6714 return NOTIFY_OK; 6715} 6716 6717static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action, 6718 void *hcpu) 6719{ 6720 switch (action) { 6721 case CPU_DOWN_PREPARE: 6722 cpuset_update_active_cpus(false); 6723 break; 6724 case CPU_DOWN_PREPARE_FROZEN: 6725 num_cpus_frozen++; 6726 partition_sched_domains(1, NULL, NULL); 6727 break; 6728 default: 6729 return NOTIFY_DONE; 6730 } 6731 return NOTIFY_OK; 6732} 6733 6734void __init sched_init_smp(void) 6735{ 6736 cpumask_var_t non_isolated_cpus; 6737 6738 alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL); 6739 alloc_cpumask_var(&fallback_doms, GFP_KERNEL); 6740 6741 sched_init_numa(); 6742 6743 /* 6744 * There's no userspace yet to cause hotplug operations; hence all the 6745 * cpu masks are stable and all blatant races in the below code cannot 6746 * happen. 6747 */ 6748 mutex_lock(&sched_domains_mutex); 6749 init_sched_domains(cpu_active_mask); 6750 cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map); 6751 if (cpumask_empty(non_isolated_cpus)) 6752 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus); 6753 mutex_unlock(&sched_domains_mutex); 6754 6755 hotcpu_notifier(sched_domains_numa_masks_update, CPU_PRI_SCHED_ACTIVE); 6756 hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE); 6757 hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE); 6758 6759 init_hrtick(); 6760 6761 /* Move init over to a non-isolated CPU */ 6762 if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0) 6763 BUG(); 6764 sched_init_granularity(); 6765 free_cpumask_var(non_isolated_cpus); 6766 6767 init_sched_rt_class(); 6768 init_sched_dl_class(); 6769} 6770#else 6771void __init sched_init_smp(void) 6772{ 6773 sched_init_granularity(); 6774} 6775#endif /* CONFIG_SMP */ 6776 6777const_debug unsigned int sysctl_timer_migration = 1; 6778 6779int in_sched_functions(unsigned long addr) 6780{ 6781 return in_lock_functions(addr) || 6782 (addr >= (unsigned long)__sched_text_start 6783 && addr < (unsigned long)__sched_text_end); 6784} 6785 6786#ifdef CONFIG_CGROUP_SCHED 6787/* 6788 * Default task group. 6789 * Every task in system belongs to this group at bootup. 6790 */ 6791struct task_group root_task_group; 6792LIST_HEAD(task_groups); 6793#endif 6794 6795DECLARE_PER_CPU(cpumask_var_t, load_balance_mask); 6796 6797void __init sched_init(void) 6798{ 6799 int i, j; 6800 unsigned long alloc_size = 0, ptr; 6801 6802#ifdef CONFIG_FAIR_GROUP_SCHED 6803 alloc_size += 2 * nr_cpu_ids * sizeof(void **); 6804#endif 6805#ifdef CONFIG_RT_GROUP_SCHED 6806 alloc_size += 2 * nr_cpu_ids * sizeof(void **); 6807#endif 6808#ifdef CONFIG_CPUMASK_OFFSTACK 6809 alloc_size += num_possible_cpus() * cpumask_size(); 6810#endif 6811 if (alloc_size) { 6812 ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT); 6813 6814#ifdef CONFIG_FAIR_GROUP_SCHED 6815 root_task_group.se = (struct sched_entity **)ptr; 6816 ptr += nr_cpu_ids * sizeof(void **); 6817 6818 root_task_group.cfs_rq = (struct cfs_rq **)ptr; 6819 ptr += nr_cpu_ids * sizeof(void **); 6820 6821#endif /* CONFIG_FAIR_GROUP_SCHED */ 6822#ifdef CONFIG_RT_GROUP_SCHED 6823 root_task_group.rt_se = (struct sched_rt_entity **)ptr; 6824 ptr += nr_cpu_ids * sizeof(void **); 6825 6826 root_task_group.rt_rq = (struct rt_rq **)ptr; 6827 ptr += nr_cpu_ids * sizeof(void **); 6828 6829#endif /* CONFIG_RT_GROUP_SCHED */ 6830#ifdef CONFIG_CPUMASK_OFFSTACK 6831 for_each_possible_cpu(i) { 6832 per_cpu(load_balance_mask, i) = (void *)ptr; 6833 ptr += cpumask_size(); 6834 } 6835#endif /* CONFIG_CPUMASK_OFFSTACK */ 6836 } 6837 6838 init_rt_bandwidth(&def_rt_bandwidth, 6839 global_rt_period(), global_rt_runtime()); 6840 init_dl_bandwidth(&def_dl_bandwidth, 6841 global_rt_period(), global_rt_runtime()); 6842 6843#ifdef CONFIG_SMP 6844 init_defrootdomain(); 6845#endif 6846 6847#ifdef CONFIG_RT_GROUP_SCHED 6848 init_rt_bandwidth(&root_task_group.rt_bandwidth, 6849 global_rt_period(), global_rt_runtime()); 6850#endif /* CONFIG_RT_GROUP_SCHED */ 6851 6852#ifdef CONFIG_CGROUP_SCHED 6853 list_add(&root_task_group.list, &task_groups); 6854 INIT_LIST_HEAD(&root_task_group.children); 6855 INIT_LIST_HEAD(&root_task_group.siblings); 6856 autogroup_init(&init_task); 6857 6858#endif /* CONFIG_CGROUP_SCHED */ 6859 6860 for_each_possible_cpu(i) { 6861 struct rq *rq; 6862 6863 rq = cpu_rq(i); 6864 raw_spin_lock_init(&rq->lock); 6865 rq->nr_running = 0; 6866 rq->calc_load_active = 0; 6867 rq->calc_load_update = jiffies + LOAD_FREQ; 6868 init_cfs_rq(&rq->cfs); 6869 init_rt_rq(&rq->rt, rq); 6870 init_dl_rq(&rq->dl, rq); 6871#ifdef CONFIG_FAIR_GROUP_SCHED 6872 root_task_group.shares = ROOT_TASK_GROUP_LOAD; 6873 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list); 6874 /* 6875 * How much cpu bandwidth does root_task_group get? 6876 * 6877 * In case of task-groups formed thr' the cgroup filesystem, it 6878 * gets 100% of the cpu resources in the system. This overall 6879 * system cpu resource is divided among the tasks of 6880 * root_task_group and its child task-groups in a fair manner, 6881 * based on each entity's (task or task-group's) weight 6882 * (se->load.weight). 6883 * 6884 * In other words, if root_task_group has 10 tasks of weight 6885 * 1024) and two child groups A0 and A1 (of weight 1024 each), 6886 * then A0's share of the cpu resource is: 6887 * 6888 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33% 6889 * 6890 * We achieve this by letting root_task_group's tasks sit 6891 * directly in rq->cfs (i.e root_task_group->se[] = NULL). 6892 */ 6893 init_cfs_bandwidth(&root_task_group.cfs_bandwidth); 6894 init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL); 6895#endif /* CONFIG_FAIR_GROUP_SCHED */ 6896 6897 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime; 6898#ifdef CONFIG_RT_GROUP_SCHED 6899 init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL); 6900#endif 6901 6902 for (j = 0; j < CPU_LOAD_IDX_MAX; j++) 6903 rq->cpu_load[j] = 0; 6904 6905 rq->last_load_update_tick = jiffies; 6906 6907#ifdef CONFIG_SMP 6908 rq->sd = NULL; 6909 rq->rd = NULL; 6910 rq->cpu_power = SCHED_POWER_SCALE; 6911 rq->post_schedule = 0; 6912 rq->active_balance = 0; 6913 rq->next_balance = jiffies; 6914 rq->push_cpu = 0; 6915 rq->cpu = i; 6916 rq->online = 0; 6917 rq->idle_stamp = 0; 6918 rq->avg_idle = 2*sysctl_sched_migration_cost; 6919 rq->max_idle_balance_cost = sysctl_sched_migration_cost; 6920 6921 INIT_LIST_HEAD(&rq->cfs_tasks); 6922 6923 rq_attach_root(rq, &def_root_domain); 6924#ifdef CONFIG_NO_HZ_COMMON 6925 rq->nohz_flags = 0; 6926#endif 6927#ifdef CONFIG_NO_HZ_FULL 6928 rq->last_sched_tick = 0; 6929#endif 6930#endif 6931 init_rq_hrtick(rq); 6932 atomic_set(&rq->nr_iowait, 0); 6933 } 6934 6935 set_load_weight(&init_task); 6936 6937#ifdef CONFIG_PREEMPT_NOTIFIERS 6938 INIT_HLIST_HEAD(&init_task.preempt_notifiers); 6939#endif 6940 6941 /* 6942 * The boot idle thread does lazy MMU switching as well: 6943 */ 6944 atomic_inc(&init_mm.mm_count); 6945 enter_lazy_tlb(&init_mm, current); 6946 6947 /* 6948 * Make us the idle thread. Technically, schedule() should not be 6949 * called from this thread, however somewhere below it might be, 6950 * but because we are the idle thread, we just pick up running again 6951 * when this runqueue becomes "idle". 6952 */ 6953 init_idle(current, smp_processor_id()); 6954 6955 calc_load_update = jiffies + LOAD_FREQ; 6956 6957 /* 6958 * During early bootup we pretend to be a normal task: 6959 */ 6960 current->sched_class = &fair_sched_class; 6961 6962#ifdef CONFIG_SMP 6963 zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT); 6964 /* May be allocated at isolcpus cmdline parse time */ 6965 if (cpu_isolated_map == NULL) 6966 zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT); 6967 idle_thread_set_boot_cpu(); 6968#endif 6969 init_sched_fair_class(); 6970 6971 scheduler_running = 1; 6972} 6973 6974#ifdef CONFIG_DEBUG_ATOMIC_SLEEP 6975static inline int preempt_count_equals(int preempt_offset) 6976{ 6977 int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth(); 6978 6979 return (nested == preempt_offset); 6980} 6981 6982void __might_sleep(const char *file, int line, int preempt_offset) 6983{ 6984 static unsigned long prev_jiffy; /* ratelimiting */ 6985 6986 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */ 6987 if ((preempt_count_equals(preempt_offset) && !irqs_disabled() && 6988 !is_idle_task(current)) || 6989 system_state != SYSTEM_RUNNING || oops_in_progress) 6990 return; 6991 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) 6992 return; 6993 prev_jiffy = jiffies; 6994 6995 printk(KERN_ERR 6996 "BUG: sleeping function called from invalid context at %s:%d\n", 6997 file, line); 6998 printk(KERN_ERR 6999 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n", 7000 in_atomic(), irqs_disabled(), 7001 current->pid, current->comm); 7002 7003 debug_show_held_locks(current); 7004 if (irqs_disabled()) 7005 print_irqtrace_events(current); 7006#ifdef CONFIG_DEBUG_PREEMPT 7007 if (!preempt_count_equals(preempt_offset)) { 7008 pr_err("Preemption disabled at:"); 7009 print_ip_sym(current->preempt_disable_ip); 7010 pr_cont("\n"); 7011 } 7012#endif 7013 dump_stack(); 7014} 7015EXPORT_SYMBOL(__might_sleep); 7016#endif 7017 7018#ifdef CONFIG_MAGIC_SYSRQ 7019static void normalize_task(struct rq *rq, struct task_struct *p) 7020{ 7021 const struct sched_class *prev_class = p->sched_class; 7022 struct sched_attr attr = { 7023 .sched_policy = SCHED_NORMAL, 7024 }; 7025 int old_prio = p->prio; 7026 int on_rq; 7027 7028 on_rq = p->on_rq; 7029 if (on_rq) 7030 dequeue_task(rq, p, 0); 7031 __setscheduler(rq, p, &attr); 7032 if (on_rq) { 7033 enqueue_task(rq, p, 0); 7034 resched_task(rq->curr); 7035 } 7036 7037 check_class_changed(rq, p, prev_class, old_prio); 7038} 7039 7040void normalize_rt_tasks(void) 7041{ 7042 struct task_struct *g, *p; 7043 unsigned long flags; 7044 struct rq *rq; 7045 7046 read_lock_irqsave(&tasklist_lock, flags); 7047 do_each_thread(g, p) { 7048 /* 7049 * Only normalize user tasks: 7050 */ 7051 if (!p->mm) 7052 continue; 7053 7054 p->se.exec_start = 0; 7055#ifdef CONFIG_SCHEDSTATS 7056 p->se.statistics.wait_start = 0; 7057 p->se.statistics.sleep_start = 0; 7058 p->se.statistics.block_start = 0; 7059#endif 7060 7061 if (!dl_task(p) && !rt_task(p)) { 7062 /* 7063 * Renice negative nice level userspace 7064 * tasks back to 0: 7065 */ 7066 if (task_nice(p) < 0 && p->mm) 7067 set_user_nice(p, 0); 7068 continue; 7069 } 7070 7071 raw_spin_lock(&p->pi_lock); 7072 rq = __task_rq_lock(p); 7073 7074 normalize_task(rq, p); 7075 7076 __task_rq_unlock(rq); 7077 raw_spin_unlock(&p->pi_lock); 7078 } while_each_thread(g, p); 7079 7080 read_unlock_irqrestore(&tasklist_lock, flags); 7081} 7082 7083#endif /* CONFIG_MAGIC_SYSRQ */ 7084 7085#if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) 7086/* 7087 * These functions are only useful for the IA64 MCA handling, or kdb. 7088 * 7089 * They can only be called when the whole system has been 7090 * stopped - every CPU needs to be quiescent, and no scheduling 7091 * activity can take place. Using them for anything else would 7092 * be a serious bug, and as a result, they aren't even visible 7093 * under any other configuration. 7094 */ 7095 7096/** 7097 * curr_task - return the current task for a given cpu. 7098 * @cpu: the processor in question. 7099 * 7100 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! 7101 * 7102 * Return: The current task for @cpu. 7103 */ 7104struct task_struct *curr_task(int cpu) 7105{ 7106 return cpu_curr(cpu); 7107} 7108 7109#endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */ 7110 7111#ifdef CONFIG_IA64 7112/** 7113 * set_curr_task - set the current task for a given cpu. 7114 * @cpu: the processor in question. 7115 * @p: the task pointer to set. 7116 * 7117 * Description: This function must only be used when non-maskable interrupts 7118 * are serviced on a separate stack. It allows the architecture to switch the 7119 * notion of the current task on a cpu in a non-blocking manner. This function 7120 * must be called with all CPU's synchronized, and interrupts disabled, the 7121 * and caller must save the original value of the current task (see 7122 * curr_task() above) and restore that value before reenabling interrupts and 7123 * re-starting the system. 7124 * 7125 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! 7126 */ 7127void set_curr_task(int cpu, struct task_struct *p) 7128{ 7129 cpu_curr(cpu) = p; 7130} 7131 7132#endif 7133 7134#ifdef CONFIG_CGROUP_SCHED 7135/* task_group_lock serializes the addition/removal of task groups */ 7136static DEFINE_SPINLOCK(task_group_lock); 7137 7138static void free_sched_group(struct task_group *tg) 7139{ 7140 free_fair_sched_group(tg); 7141 free_rt_sched_group(tg); 7142 autogroup_free(tg); 7143 kfree(tg); 7144} 7145 7146/* allocate runqueue etc for a new task group */ 7147struct task_group *sched_create_group(struct task_group *parent) 7148{ 7149 struct task_group *tg; 7150 7151 tg = kzalloc(sizeof(*tg), GFP_KERNEL); 7152 if (!tg) 7153 return ERR_PTR(-ENOMEM); 7154 7155 if (!alloc_fair_sched_group(tg, parent)) 7156 goto err; 7157 7158 if (!alloc_rt_sched_group(tg, parent)) 7159 goto err; 7160 7161 return tg; 7162 7163err: 7164 free_sched_group(tg); 7165 return ERR_PTR(-ENOMEM); 7166} 7167 7168void sched_online_group(struct task_group *tg, struct task_group *parent) 7169{ 7170 unsigned long flags; 7171 7172 spin_lock_irqsave(&task_group_lock, flags); 7173 list_add_rcu(&tg->list, &task_groups); 7174 7175 WARN_ON(!parent); /* root should already exist */ 7176 7177 tg->parent = parent; 7178 INIT_LIST_HEAD(&tg->children); 7179 list_add_rcu(&tg->siblings, &parent->children); 7180 spin_unlock_irqrestore(&task_group_lock, flags); 7181} 7182 7183/* rcu callback to free various structures associated with a task group */ 7184static void free_sched_group_rcu(struct rcu_head *rhp) 7185{ 7186 /* now it should be safe to free those cfs_rqs */ 7187 free_sched_group(container_of(rhp, struct task_group, rcu)); 7188} 7189 7190/* Destroy runqueue etc associated with a task group */ 7191void sched_destroy_group(struct task_group *tg) 7192{ 7193 /* wait for possible concurrent references to cfs_rqs complete */ 7194 call_rcu(&tg->rcu, free_sched_group_rcu); 7195} 7196 7197void sched_offline_group(struct task_group *tg) 7198{ 7199 unsigned long flags; 7200 int i; 7201 7202 /* end participation in shares distribution */ 7203 for_each_possible_cpu(i) 7204 unregister_fair_sched_group(tg, i); 7205 7206 spin_lock_irqsave(&task_group_lock, flags); 7207 list_del_rcu(&tg->list); 7208 list_del_rcu(&tg->siblings); 7209 spin_unlock_irqrestore(&task_group_lock, flags); 7210} 7211 7212/* change task's runqueue when it moves between groups. 7213 * The caller of this function should have put the task in its new group 7214 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to 7215 * reflect its new group. 7216 */ 7217void sched_move_task(struct task_struct *tsk) 7218{ 7219 struct task_group *tg; 7220 int on_rq, running; 7221 unsigned long flags; 7222 struct rq *rq; 7223 7224 rq = task_rq_lock(tsk, &flags); 7225 7226 running = task_current(rq, tsk); 7227 on_rq = tsk->on_rq; 7228 7229 if (on_rq) 7230 dequeue_task(rq, tsk, 0); 7231 if (unlikely(running)) 7232 tsk->sched_class->put_prev_task(rq, tsk); 7233 7234 tg = container_of(task_css_check(tsk, cpu_cgroup_subsys_id, 7235 lockdep_is_held(&tsk->sighand->siglock)), 7236 struct task_group, css); 7237 tg = autogroup_task_group(tsk, tg); 7238 tsk->sched_task_group = tg; 7239 7240#ifdef CONFIG_FAIR_GROUP_SCHED 7241 if (tsk->sched_class->task_move_group) 7242 tsk->sched_class->task_move_group(tsk, on_rq); 7243 else 7244#endif 7245 set_task_rq(tsk, task_cpu(tsk)); 7246 7247 if (unlikely(running)) 7248 tsk->sched_class->set_curr_task(rq); 7249 if (on_rq) 7250 enqueue_task(rq, tsk, 0); 7251 7252 task_rq_unlock(rq, tsk, &flags); 7253} 7254#endif /* CONFIG_CGROUP_SCHED */ 7255 7256#ifdef CONFIG_RT_GROUP_SCHED 7257/* 7258 * Ensure that the real time constraints are schedulable. 7259 */ 7260static DEFINE_MUTEX(rt_constraints_mutex); 7261 7262/* Must be called with tasklist_lock held */ 7263static inline int tg_has_rt_tasks(struct task_group *tg) 7264{ 7265 struct task_struct *g, *p; 7266 7267 do_each_thread(g, p) { 7268 if (rt_task(p) && task_rq(p)->rt.tg == tg) 7269 return 1; 7270 } while_each_thread(g, p); 7271 7272 return 0; 7273} 7274 7275struct rt_schedulable_data { 7276 struct task_group *tg; 7277 u64 rt_period; 7278 u64 rt_runtime; 7279}; 7280 7281static int tg_rt_schedulable(struct task_group *tg, void *data) 7282{ 7283 struct rt_schedulable_data *d = data; 7284 struct task_group *child; 7285 unsigned long total, sum = 0; 7286 u64 period, runtime; 7287 7288 period = ktime_to_ns(tg->rt_bandwidth.rt_period); 7289 runtime = tg->rt_bandwidth.rt_runtime; 7290 7291 if (tg == d->tg) { 7292 period = d->rt_period; 7293 runtime = d->rt_runtime; 7294 } 7295 7296 /* 7297 * Cannot have more runtime than the period. 7298 */ 7299 if (runtime > period && runtime != RUNTIME_INF) 7300 return -EINVAL; 7301 7302 /* 7303 * Ensure we don't starve existing RT tasks. 7304 */ 7305 if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg)) 7306 return -EBUSY; 7307 7308 total = to_ratio(period, runtime); 7309 7310 /* 7311 * Nobody can have more than the global setting allows. 7312 */ 7313 if (total > to_ratio(global_rt_period(), global_rt_runtime())) 7314 return -EINVAL; 7315 7316 /* 7317 * The sum of our children's runtime should not exceed our own. 7318 */ 7319 list_for_each_entry_rcu(child, &tg->children, siblings) { 7320 period = ktime_to_ns(child->rt_bandwidth.rt_period); 7321 runtime = child->rt_bandwidth.rt_runtime; 7322 7323 if (child == d->tg) { 7324 period = d->rt_period; 7325 runtime = d->rt_runtime; 7326 } 7327 7328 sum += to_ratio(period, runtime); 7329 } 7330 7331 if (sum > total) 7332 return -EINVAL; 7333 7334 return 0; 7335} 7336 7337static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime) 7338{ 7339 int ret; 7340 7341 struct rt_schedulable_data data = { 7342 .tg = tg, 7343 .rt_period = period, 7344 .rt_runtime = runtime, 7345 }; 7346 7347 rcu_read_lock(); 7348 ret = walk_tg_tree(tg_rt_schedulable, tg_nop, &data); 7349 rcu_read_unlock(); 7350 7351 return ret; 7352} 7353 7354static int tg_set_rt_bandwidth(struct task_group *tg, 7355 u64 rt_period, u64 rt_runtime) 7356{ 7357 int i, err = 0; 7358 7359 mutex_lock(&rt_constraints_mutex); 7360 read_lock(&tasklist_lock); 7361 err = __rt_schedulable(tg, rt_period, rt_runtime); 7362 if (err) 7363 goto unlock; 7364 7365 raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock); 7366 tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period); 7367 tg->rt_bandwidth.rt_runtime = rt_runtime; 7368 7369 for_each_possible_cpu(i) { 7370 struct rt_rq *rt_rq = tg->rt_rq[i]; 7371 7372 raw_spin_lock(&rt_rq->rt_runtime_lock); 7373 rt_rq->rt_runtime = rt_runtime; 7374 raw_spin_unlock(&rt_rq->rt_runtime_lock); 7375 } 7376 raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock); 7377unlock: 7378 read_unlock(&tasklist_lock); 7379 mutex_unlock(&rt_constraints_mutex); 7380 7381 return err; 7382} 7383 7384static int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us) 7385{ 7386 u64 rt_runtime, rt_period; 7387 7388 rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period); 7389 rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC; 7390 if (rt_runtime_us < 0) 7391 rt_runtime = RUNTIME_INF; 7392 7393 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); 7394} 7395 7396static long sched_group_rt_runtime(struct task_group *tg) 7397{ 7398 u64 rt_runtime_us; 7399 7400 if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF) 7401 return -1; 7402 7403 rt_runtime_us = tg->rt_bandwidth.rt_runtime; 7404 do_div(rt_runtime_us, NSEC_PER_USEC); 7405 return rt_runtime_us; 7406} 7407 7408static int sched_group_set_rt_period(struct task_group *tg, long rt_period_us) 7409{ 7410 u64 rt_runtime, rt_period; 7411 7412 rt_period = (u64)rt_period_us * NSEC_PER_USEC; 7413 rt_runtime = tg->rt_bandwidth.rt_runtime; 7414 7415 if (rt_period == 0) 7416 return -EINVAL; 7417 7418 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); 7419} 7420 7421static long sched_group_rt_period(struct task_group *tg) 7422{ 7423 u64 rt_period_us; 7424 7425 rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period); 7426 do_div(rt_period_us, NSEC_PER_USEC); 7427 return rt_period_us; 7428} 7429#endif /* CONFIG_RT_GROUP_SCHED */ 7430 7431#ifdef CONFIG_RT_GROUP_SCHED 7432static int sched_rt_global_constraints(void) 7433{ 7434 int ret = 0; 7435 7436 mutex_lock(&rt_constraints_mutex); 7437 read_lock(&tasklist_lock); 7438 ret = __rt_schedulable(NULL, 0, 0); 7439 read_unlock(&tasklist_lock); 7440 mutex_unlock(&rt_constraints_mutex); 7441 7442 return ret; 7443} 7444 7445static int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk) 7446{ 7447 /* Don't accept realtime tasks when there is no way for them to run */ 7448 if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0) 7449 return 0; 7450 7451 return 1; 7452} 7453 7454#else /* !CONFIG_RT_GROUP_SCHED */ 7455static int sched_rt_global_constraints(void) 7456{ 7457 unsigned long flags; 7458 int i, ret = 0; 7459 7460 raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags); 7461 for_each_possible_cpu(i) { 7462 struct rt_rq *rt_rq = &cpu_rq(i)->rt; 7463 7464 raw_spin_lock(&rt_rq->rt_runtime_lock); 7465 rt_rq->rt_runtime = global_rt_runtime(); 7466 raw_spin_unlock(&rt_rq->rt_runtime_lock); 7467 } 7468 raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags); 7469 7470 return ret; 7471} 7472#endif /* CONFIG_RT_GROUP_SCHED */ 7473 7474static int sched_dl_global_constraints(void) 7475{ 7476 u64 runtime = global_rt_runtime(); 7477 u64 period = global_rt_period(); 7478 u64 new_bw = to_ratio(period, runtime); 7479 int cpu, ret = 0; 7480 unsigned long flags; 7481 7482 /* 7483 * Here we want to check the bandwidth not being set to some 7484 * value smaller than the currently allocated bandwidth in 7485 * any of the root_domains. 7486 * 7487 * FIXME: Cycling on all the CPUs is overdoing, but simpler than 7488 * cycling on root_domains... Discussion on different/better 7489 * solutions is welcome! 7490 */ 7491 for_each_possible_cpu(cpu) { 7492 struct dl_bw *dl_b = dl_bw_of(cpu); 7493 7494 raw_spin_lock_irqsave(&dl_b->lock, flags); 7495 if (new_bw < dl_b->total_bw) 7496 ret = -EBUSY; 7497 raw_spin_unlock_irqrestore(&dl_b->lock, flags); 7498 7499 if (ret) 7500 break; 7501 } 7502 7503 return ret; 7504} 7505 7506static void sched_dl_do_global(void) 7507{ 7508 u64 new_bw = -1; 7509 int cpu; 7510 unsigned long flags; 7511 7512 def_dl_bandwidth.dl_period = global_rt_period(); 7513 def_dl_bandwidth.dl_runtime = global_rt_runtime(); 7514 7515 if (global_rt_runtime() != RUNTIME_INF) 7516 new_bw = to_ratio(global_rt_period(), global_rt_runtime()); 7517 7518 /* 7519 * FIXME: As above... 7520 */ 7521 for_each_possible_cpu(cpu) { 7522 struct dl_bw *dl_b = dl_bw_of(cpu); 7523 7524 raw_spin_lock_irqsave(&dl_b->lock, flags); 7525 dl_b->bw = new_bw; 7526 raw_spin_unlock_irqrestore(&dl_b->lock, flags); 7527 } 7528} 7529 7530static int sched_rt_global_validate(void) 7531{ 7532 if (sysctl_sched_rt_period <= 0) 7533 return -EINVAL; 7534 7535 if ((sysctl_sched_rt_runtime != RUNTIME_INF) && 7536 (sysctl_sched_rt_runtime > sysctl_sched_rt_period)) 7537 return -EINVAL; 7538 7539 return 0; 7540} 7541 7542static void sched_rt_do_global(void) 7543{ 7544 def_rt_bandwidth.rt_runtime = global_rt_runtime(); 7545 def_rt_bandwidth.rt_period = ns_to_ktime(global_rt_period()); 7546} 7547 7548int sched_rt_handler(struct ctl_table *table, int write, 7549 void __user *buffer, size_t *lenp, 7550 loff_t *ppos) 7551{ 7552 int old_period, old_runtime; 7553 static DEFINE_MUTEX(mutex); 7554 int ret; 7555 7556 mutex_lock(&mutex); 7557 old_period = sysctl_sched_rt_period; 7558 old_runtime = sysctl_sched_rt_runtime; 7559 7560 ret = proc_dointvec(table, write, buffer, lenp, ppos); 7561 7562 if (!ret && write) { 7563 ret = sched_rt_global_validate(); 7564 if (ret) 7565 goto undo; 7566 7567 ret = sched_rt_global_constraints(); 7568 if (ret) 7569 goto undo; 7570 7571 ret = sched_dl_global_constraints(); 7572 if (ret) 7573 goto undo; 7574 7575 sched_rt_do_global(); 7576 sched_dl_do_global(); 7577 } 7578 if (0) { 7579undo: 7580 sysctl_sched_rt_period = old_period; 7581 sysctl_sched_rt_runtime = old_runtime; 7582 } 7583 mutex_unlock(&mutex); 7584 7585 return ret; 7586} 7587 7588int sched_rr_handler(struct ctl_table *table, int write, 7589 void __user *buffer, size_t *lenp, 7590 loff_t *ppos) 7591{ 7592 int ret; 7593 static DEFINE_MUTEX(mutex); 7594 7595 mutex_lock(&mutex); 7596 ret = proc_dointvec(table, write, buffer, lenp, ppos); 7597 /* make sure that internally we keep jiffies */ 7598 /* also, writing zero resets timeslice to default */ 7599 if (!ret && write) { 7600 sched_rr_timeslice = sched_rr_timeslice <= 0 ? 7601 RR_TIMESLICE : msecs_to_jiffies(sched_rr_timeslice); 7602 } 7603 mutex_unlock(&mutex); 7604 return ret; 7605} 7606 7607#ifdef CONFIG_CGROUP_SCHED 7608 7609static inline struct task_group *css_tg(struct cgroup_subsys_state *css) 7610{ 7611 return css ? container_of(css, struct task_group, css) : NULL; 7612} 7613 7614static struct cgroup_subsys_state * 7615cpu_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) 7616{ 7617 struct task_group *parent = css_tg(parent_css); 7618 struct task_group *tg; 7619 7620 if (!parent) { 7621 /* This is early initialization for the top cgroup */ 7622 return &root_task_group.css; 7623 } 7624 7625 tg = sched_create_group(parent); 7626 if (IS_ERR(tg)) 7627 return ERR_PTR(-ENOMEM); 7628 7629 return &tg->css; 7630} 7631 7632static int cpu_cgroup_css_online(struct cgroup_subsys_state *css) 7633{ 7634 struct task_group *tg = css_tg(css); 7635 struct task_group *parent = css_tg(css_parent(css)); 7636 7637 if (parent) 7638 sched_online_group(tg, parent); 7639 return 0; 7640} 7641 7642static void cpu_cgroup_css_free(struct cgroup_subsys_state *css) 7643{ 7644 struct task_group *tg = css_tg(css); 7645 7646 sched_destroy_group(tg); 7647} 7648 7649static void cpu_cgroup_css_offline(struct cgroup_subsys_state *css) 7650{ 7651 struct task_group *tg = css_tg(css); 7652 7653 sched_offline_group(tg); 7654} 7655 7656static int cpu_cgroup_can_attach(struct cgroup_subsys_state *css, 7657 struct cgroup_taskset *tset) 7658{ 7659 struct task_struct *task; 7660 7661 cgroup_taskset_for_each(task, css, tset) { 7662#ifdef CONFIG_RT_GROUP_SCHED 7663 if (!sched_rt_can_attach(css_tg(css), task)) 7664 return -EINVAL; 7665#else 7666 /* We don't support RT-tasks being in separate groups */ 7667 if (task->sched_class != &fair_sched_class) 7668 return -EINVAL; 7669#endif 7670 } 7671 return 0; 7672} 7673 7674static void cpu_cgroup_attach(struct cgroup_subsys_state *css, 7675 struct cgroup_taskset *tset) 7676{ 7677 struct task_struct *task; 7678 7679 cgroup_taskset_for_each(task, css, tset) 7680 sched_move_task(task); 7681} 7682 7683static void cpu_cgroup_exit(struct cgroup_subsys_state *css, 7684 struct cgroup_subsys_state *old_css, 7685 struct task_struct *task) 7686{ 7687 /* 7688 * cgroup_exit() is called in the copy_process() failure path. 7689 * Ignore this case since the task hasn't ran yet, this avoids 7690 * trying to poke a half freed task state from generic code. 7691 */ 7692 if (!(task->flags & PF_EXITING)) 7693 return; 7694 7695 sched_move_task(task); 7696} 7697 7698#ifdef CONFIG_FAIR_GROUP_SCHED 7699static int cpu_shares_write_u64(struct cgroup_subsys_state *css, 7700 struct cftype *cftype, u64 shareval) 7701{ 7702 return sched_group_set_shares(css_tg(css), scale_load(shareval)); 7703} 7704 7705static u64 cpu_shares_read_u64(struct cgroup_subsys_state *css, 7706 struct cftype *cft) 7707{ 7708 struct task_group *tg = css_tg(css); 7709 7710 return (u64) scale_load_down(tg->shares); 7711} 7712 7713#ifdef CONFIG_CFS_BANDWIDTH 7714static DEFINE_MUTEX(cfs_constraints_mutex); 7715 7716const u64 max_cfs_quota_period = 1 * NSEC_PER_SEC; /* 1s */ 7717const u64 min_cfs_quota_period = 1 * NSEC_PER_MSEC; /* 1ms */ 7718 7719static int __cfs_schedulable(struct task_group *tg, u64 period, u64 runtime); 7720 7721static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota) 7722{ 7723 int i, ret = 0, runtime_enabled, runtime_was_enabled; 7724 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 7725 7726 if (tg == &root_task_group) 7727 return -EINVAL; 7728 7729 /* 7730 * Ensure we have at some amount of bandwidth every period. This is 7731 * to prevent reaching a state of large arrears when throttled via 7732 * entity_tick() resulting in prolonged exit starvation. 7733 */ 7734 if (quota < min_cfs_quota_period || period < min_cfs_quota_period) 7735 return -EINVAL; 7736 7737 /* 7738 * Likewise, bound things on the otherside by preventing insane quota 7739 * periods. This also allows us to normalize in computing quota 7740 * feasibility. 7741 */ 7742 if (period > max_cfs_quota_period) 7743 return -EINVAL; 7744 7745 mutex_lock(&cfs_constraints_mutex); 7746 ret = __cfs_schedulable(tg, period, quota); 7747 if (ret) 7748 goto out_unlock; 7749 7750 runtime_enabled = quota != RUNTIME_INF; 7751 runtime_was_enabled = cfs_b->quota != RUNTIME_INF; 7752 /* 7753 * If we need to toggle cfs_bandwidth_used, off->on must occur 7754 * before making related changes, and on->off must occur afterwards 7755 */ 7756 if (runtime_enabled && !runtime_was_enabled) 7757 cfs_bandwidth_usage_inc(); 7758 raw_spin_lock_irq(&cfs_b->lock); 7759 cfs_b->period = ns_to_ktime(period); 7760 cfs_b->quota = quota; 7761 7762 __refill_cfs_bandwidth_runtime(cfs_b); 7763 /* restart the period timer (if active) to handle new period expiry */ 7764 if (runtime_enabled && cfs_b->timer_active) { 7765 /* force a reprogram */ 7766 cfs_b->timer_active = 0; 7767 __start_cfs_bandwidth(cfs_b); 7768 } 7769 raw_spin_unlock_irq(&cfs_b->lock); 7770 7771 for_each_possible_cpu(i) { 7772 struct cfs_rq *cfs_rq = tg->cfs_rq[i]; 7773 struct rq *rq = cfs_rq->rq; 7774 7775 raw_spin_lock_irq(&rq->lock); 7776 cfs_rq->runtime_enabled = runtime_enabled; 7777 cfs_rq->runtime_remaining = 0; 7778 7779 if (cfs_rq->throttled) 7780 unthrottle_cfs_rq(cfs_rq); 7781 raw_spin_unlock_irq(&rq->lock); 7782 } 7783 if (runtime_was_enabled && !runtime_enabled) 7784 cfs_bandwidth_usage_dec(); 7785out_unlock: 7786 mutex_unlock(&cfs_constraints_mutex); 7787 7788 return ret; 7789} 7790 7791int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us) 7792{ 7793 u64 quota, period; 7794 7795 period = ktime_to_ns(tg->cfs_bandwidth.period); 7796 if (cfs_quota_us < 0) 7797 quota = RUNTIME_INF; 7798 else 7799 quota = (u64)cfs_quota_us * NSEC_PER_USEC; 7800 7801 return tg_set_cfs_bandwidth(tg, period, quota); 7802} 7803 7804long tg_get_cfs_quota(struct task_group *tg) 7805{ 7806 u64 quota_us; 7807 7808 if (tg->cfs_bandwidth.quota == RUNTIME_INF) 7809 return -1; 7810 7811 quota_us = tg->cfs_bandwidth.quota; 7812 do_div(quota_us, NSEC_PER_USEC); 7813 7814 return quota_us; 7815} 7816 7817int tg_set_cfs_period(struct task_group *tg, long cfs_period_us) 7818{ 7819 u64 quota, period; 7820 7821 period = (u64)cfs_period_us * NSEC_PER_USEC; 7822 quota = tg->cfs_bandwidth.quota; 7823 7824 return tg_set_cfs_bandwidth(tg, period, quota); 7825} 7826 7827long tg_get_cfs_period(struct task_group *tg) 7828{ 7829 u64 cfs_period_us; 7830 7831 cfs_period_us = ktime_to_ns(tg->cfs_bandwidth.period); 7832 do_div(cfs_period_us, NSEC_PER_USEC); 7833 7834 return cfs_period_us; 7835} 7836 7837static s64 cpu_cfs_quota_read_s64(struct cgroup_subsys_state *css, 7838 struct cftype *cft) 7839{ 7840 return tg_get_cfs_quota(css_tg(css)); 7841} 7842 7843static int cpu_cfs_quota_write_s64(struct cgroup_subsys_state *css, 7844 struct cftype *cftype, s64 cfs_quota_us) 7845{ 7846 return tg_set_cfs_quota(css_tg(css), cfs_quota_us); 7847} 7848 7849static u64 cpu_cfs_period_read_u64(struct cgroup_subsys_state *css, 7850 struct cftype *cft) 7851{ 7852 return tg_get_cfs_period(css_tg(css)); 7853} 7854 7855static int cpu_cfs_period_write_u64(struct cgroup_subsys_state *css, 7856 struct cftype *cftype, u64 cfs_period_us) 7857{ 7858 return tg_set_cfs_period(css_tg(css), cfs_period_us); 7859} 7860 7861struct cfs_schedulable_data { 7862 struct task_group *tg; 7863 u64 period, quota; 7864}; 7865 7866/* 7867 * normalize group quota/period to be quota/max_period 7868 * note: units are usecs 7869 */ 7870static u64 normalize_cfs_quota(struct task_group *tg, 7871 struct cfs_schedulable_data *d) 7872{ 7873 u64 quota, period; 7874 7875 if (tg == d->tg) { 7876 period = d->period; 7877 quota = d->quota; 7878 } else { 7879 period = tg_get_cfs_period(tg); 7880 quota = tg_get_cfs_quota(tg); 7881 } 7882 7883 /* note: these should typically be equivalent */ 7884 if (quota == RUNTIME_INF || quota == -1) 7885 return RUNTIME_INF; 7886 7887 return to_ratio(period, quota); 7888} 7889 7890static int tg_cfs_schedulable_down(struct task_group *tg, void *data) 7891{ 7892 struct cfs_schedulable_data *d = data; 7893 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 7894 s64 quota = 0, parent_quota = -1; 7895 7896 if (!tg->parent) { 7897 quota = RUNTIME_INF; 7898 } else { 7899 struct cfs_bandwidth *parent_b = &tg->parent->cfs_bandwidth; 7900 7901 quota = normalize_cfs_quota(tg, d); 7902 parent_quota = parent_b->hierarchal_quota; 7903 7904 /* 7905 * ensure max(child_quota) <= parent_quota, inherit when no 7906 * limit is set 7907 */ 7908 if (quota == RUNTIME_INF) 7909 quota = parent_quota; 7910 else if (parent_quota != RUNTIME_INF && quota > parent_quota) 7911 return -EINVAL; 7912 } 7913 cfs_b->hierarchal_quota = quota; 7914 7915 return 0; 7916} 7917 7918static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota) 7919{ 7920 int ret; 7921 struct cfs_schedulable_data data = { 7922 .tg = tg, 7923 .period = period, 7924 .quota = quota, 7925 }; 7926 7927 if (quota != RUNTIME_INF) { 7928 do_div(data.period, NSEC_PER_USEC); 7929 do_div(data.quota, NSEC_PER_USEC); 7930 } 7931 7932 rcu_read_lock(); 7933 ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data); 7934 rcu_read_unlock(); 7935 7936 return ret; 7937} 7938 7939static int cpu_stats_show(struct seq_file *sf, void *v) 7940{ 7941 struct task_group *tg = css_tg(seq_css(sf)); 7942 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 7943 7944 seq_printf(sf, "nr_periods %d\n", cfs_b->nr_periods); 7945 seq_printf(sf, "nr_throttled %d\n", cfs_b->nr_throttled); 7946 seq_printf(sf, "throttled_time %llu\n", cfs_b->throttled_time); 7947 7948 return 0; 7949} 7950#endif /* CONFIG_CFS_BANDWIDTH */ 7951#endif /* CONFIG_FAIR_GROUP_SCHED */ 7952 7953#ifdef CONFIG_RT_GROUP_SCHED 7954static int cpu_rt_runtime_write(struct cgroup_subsys_state *css, 7955 struct cftype *cft, s64 val) 7956{ 7957 return sched_group_set_rt_runtime(css_tg(css), val); 7958} 7959 7960static s64 cpu_rt_runtime_read(struct cgroup_subsys_state *css, 7961 struct cftype *cft) 7962{ 7963 return sched_group_rt_runtime(css_tg(css)); 7964} 7965 7966static int cpu_rt_period_write_uint(struct cgroup_subsys_state *css, 7967 struct cftype *cftype, u64 rt_period_us) 7968{ 7969 return sched_group_set_rt_period(css_tg(css), rt_period_us); 7970} 7971 7972static u64 cpu_rt_period_read_uint(struct cgroup_subsys_state *css, 7973 struct cftype *cft) 7974{ 7975 return sched_group_rt_period(css_tg(css)); 7976} 7977#endif /* CONFIG_RT_GROUP_SCHED */ 7978 7979static struct cftype cpu_files[] = { 7980#ifdef CONFIG_FAIR_GROUP_SCHED 7981 { 7982 .name = "shares", 7983 .read_u64 = cpu_shares_read_u64, 7984 .write_u64 = cpu_shares_write_u64, 7985 }, 7986#endif 7987#ifdef CONFIG_CFS_BANDWIDTH 7988 { 7989 .name = "cfs_quota_us", 7990 .read_s64 = cpu_cfs_quota_read_s64, 7991 .write_s64 = cpu_cfs_quota_write_s64, 7992 }, 7993 { 7994 .name = "cfs_period_us", 7995 .read_u64 = cpu_cfs_period_read_u64, 7996 .write_u64 = cpu_cfs_period_write_u64, 7997 }, 7998 { 7999 .name = "stat", 8000 .seq_show = cpu_stats_show, 8001 }, 8002#endif 8003#ifdef CONFIG_RT_GROUP_SCHED 8004 { 8005 .name = "rt_runtime_us", 8006 .read_s64 = cpu_rt_runtime_read, 8007 .write_s64 = cpu_rt_runtime_write, 8008 }, 8009 { 8010 .name = "rt_period_us", 8011 .read_u64 = cpu_rt_period_read_uint, 8012 .write_u64 = cpu_rt_period_write_uint, 8013 }, 8014#endif 8015 { } /* terminate */ 8016}; 8017 8018struct cgroup_subsys cpu_cgroup_subsys = { 8019 .name = "cpu", 8020 .css_alloc = cpu_cgroup_css_alloc, 8021 .css_free = cpu_cgroup_css_free, 8022 .css_online = cpu_cgroup_css_online, 8023 .css_offline = cpu_cgroup_css_offline, 8024 .can_attach = cpu_cgroup_can_attach, 8025 .attach = cpu_cgroup_attach, 8026 .exit = cpu_cgroup_exit, 8027 .subsys_id = cpu_cgroup_subsys_id, 8028 .base_cftypes = cpu_files, 8029 .early_init = 1, 8030}; 8031 8032#endif /* CONFIG_CGROUP_SCHED */ 8033 8034void dump_cpu_task(int cpu) 8035{ 8036 pr_info("Task dump for CPU %d:\n", cpu); 8037 sched_show_task(cpu_curr(cpu)); 8038} 8039