core.c revision 4a81e8328d3791a4f99bf5b436d050f6dc5ffea3
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#include <linux/compiler.h> 77 78#include <asm/switch_to.h> 79#include <asm/tlb.h> 80#include <asm/irq_regs.h> 81#include <asm/mutex.h> 82#ifdef CONFIG_PARAVIRT 83#include <asm/paravirt.h> 84#endif 85 86#include "sched.h" 87#include "../workqueue_internal.h" 88#include "../smpboot.h" 89 90#define CREATE_TRACE_POINTS 91#include <trace/events/sched.h> 92 93#ifdef smp_mb__before_atomic 94void __smp_mb__before_atomic(void) 95{ 96 smp_mb__before_atomic(); 97} 98EXPORT_SYMBOL(__smp_mb__before_atomic); 99#endif 100 101#ifdef smp_mb__after_atomic 102void __smp_mb__after_atomic(void) 103{ 104 smp_mb__after_atomic(); 105} 106EXPORT_SYMBOL(__smp_mb__after_atomic); 107#endif 108 109void start_bandwidth_timer(struct hrtimer *period_timer, ktime_t period) 110{ 111 unsigned long delta; 112 ktime_t soft, hard, now; 113 114 for (;;) { 115 if (hrtimer_active(period_timer)) 116 break; 117 118 now = hrtimer_cb_get_time(period_timer); 119 hrtimer_forward(period_timer, now, period); 120 121 soft = hrtimer_get_softexpires(period_timer); 122 hard = hrtimer_get_expires(period_timer); 123 delta = ktime_to_ns(ktime_sub(hard, soft)); 124 __hrtimer_start_range_ns(period_timer, soft, delta, 125 HRTIMER_MODE_ABS_PINNED, 0); 126 } 127} 128 129DEFINE_MUTEX(sched_domains_mutex); 130DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); 131 132static void update_rq_clock_task(struct rq *rq, s64 delta); 133 134void update_rq_clock(struct rq *rq) 135{ 136 s64 delta; 137 138 if (rq->skip_clock_update > 0) 139 return; 140 141 delta = sched_clock_cpu(cpu_of(rq)) - rq->clock; 142 rq->clock += delta; 143 update_rq_clock_task(rq, delta); 144} 145 146/* 147 * Debugging: various feature bits 148 */ 149 150#define SCHED_FEAT(name, enabled) \ 151 (1UL << __SCHED_FEAT_##name) * enabled | 152 153const_debug unsigned int sysctl_sched_features = 154#include "features.h" 155 0; 156 157#undef SCHED_FEAT 158 159#ifdef CONFIG_SCHED_DEBUG 160#define SCHED_FEAT(name, enabled) \ 161 #name , 162 163static const char * const sched_feat_names[] = { 164#include "features.h" 165}; 166 167#undef SCHED_FEAT 168 169static int sched_feat_show(struct seq_file *m, void *v) 170{ 171 int i; 172 173 for (i = 0; i < __SCHED_FEAT_NR; i++) { 174 if (!(sysctl_sched_features & (1UL << i))) 175 seq_puts(m, "NO_"); 176 seq_printf(m, "%s ", sched_feat_names[i]); 177 } 178 seq_puts(m, "\n"); 179 180 return 0; 181} 182 183#ifdef HAVE_JUMP_LABEL 184 185#define jump_label_key__true STATIC_KEY_INIT_TRUE 186#define jump_label_key__false STATIC_KEY_INIT_FALSE 187 188#define SCHED_FEAT(name, enabled) \ 189 jump_label_key__##enabled , 190 191struct static_key sched_feat_keys[__SCHED_FEAT_NR] = { 192#include "features.h" 193}; 194 195#undef SCHED_FEAT 196 197static void sched_feat_disable(int i) 198{ 199 if (static_key_enabled(&sched_feat_keys[i])) 200 static_key_slow_dec(&sched_feat_keys[i]); 201} 202 203static void sched_feat_enable(int i) 204{ 205 if (!static_key_enabled(&sched_feat_keys[i])) 206 static_key_slow_inc(&sched_feat_keys[i]); 207} 208#else 209static void sched_feat_disable(int i) { }; 210static void sched_feat_enable(int i) { }; 211#endif /* HAVE_JUMP_LABEL */ 212 213static int sched_feat_set(char *cmp) 214{ 215 int i; 216 int neg = 0; 217 218 if (strncmp(cmp, "NO_", 3) == 0) { 219 neg = 1; 220 cmp += 3; 221 } 222 223 for (i = 0; i < __SCHED_FEAT_NR; i++) { 224 if (strcmp(cmp, sched_feat_names[i]) == 0) { 225 if (neg) { 226 sysctl_sched_features &= ~(1UL << i); 227 sched_feat_disable(i); 228 } else { 229 sysctl_sched_features |= (1UL << i); 230 sched_feat_enable(i); 231 } 232 break; 233 } 234 } 235 236 return i; 237} 238 239static ssize_t 240sched_feat_write(struct file *filp, const char __user *ubuf, 241 size_t cnt, loff_t *ppos) 242{ 243 char buf[64]; 244 char *cmp; 245 int i; 246 247 if (cnt > 63) 248 cnt = 63; 249 250 if (copy_from_user(&buf, ubuf, cnt)) 251 return -EFAULT; 252 253 buf[cnt] = 0; 254 cmp = strstrip(buf); 255 256 i = sched_feat_set(cmp); 257 if (i == __SCHED_FEAT_NR) 258 return -EINVAL; 259 260 *ppos += cnt; 261 262 return cnt; 263} 264 265static int sched_feat_open(struct inode *inode, struct file *filp) 266{ 267 return single_open(filp, sched_feat_show, NULL); 268} 269 270static const struct file_operations sched_feat_fops = { 271 .open = sched_feat_open, 272 .write = sched_feat_write, 273 .read = seq_read, 274 .llseek = seq_lseek, 275 .release = single_release, 276}; 277 278static __init int sched_init_debug(void) 279{ 280 debugfs_create_file("sched_features", 0644, NULL, NULL, 281 &sched_feat_fops); 282 283 return 0; 284} 285late_initcall(sched_init_debug); 286#endif /* CONFIG_SCHED_DEBUG */ 287 288/* 289 * Number of tasks to iterate in a single balance run. 290 * Limited because this is done with IRQs disabled. 291 */ 292const_debug unsigned int sysctl_sched_nr_migrate = 32; 293 294/* 295 * period over which we average the RT time consumption, measured 296 * in ms. 297 * 298 * default: 1s 299 */ 300const_debug unsigned int sysctl_sched_time_avg = MSEC_PER_SEC; 301 302/* 303 * period over which we measure -rt task cpu usage in us. 304 * default: 1s 305 */ 306unsigned int sysctl_sched_rt_period = 1000000; 307 308__read_mostly int scheduler_running; 309 310/* 311 * part of the period that we allow rt tasks to run in us. 312 * default: 0.95s 313 */ 314int sysctl_sched_rt_runtime = 950000; 315 316/* 317 * __task_rq_lock - lock the rq @p resides on. 318 */ 319static inline struct rq *__task_rq_lock(struct task_struct *p) 320 __acquires(rq->lock) 321{ 322 struct rq *rq; 323 324 lockdep_assert_held(&p->pi_lock); 325 326 for (;;) { 327 rq = task_rq(p); 328 raw_spin_lock(&rq->lock); 329 if (likely(rq == task_rq(p))) 330 return rq; 331 raw_spin_unlock(&rq->lock); 332 } 333} 334 335/* 336 * task_rq_lock - lock p->pi_lock and lock the rq @p resides on. 337 */ 338static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags) 339 __acquires(p->pi_lock) 340 __acquires(rq->lock) 341{ 342 struct rq *rq; 343 344 for (;;) { 345 raw_spin_lock_irqsave(&p->pi_lock, *flags); 346 rq = task_rq(p); 347 raw_spin_lock(&rq->lock); 348 if (likely(rq == task_rq(p))) 349 return rq; 350 raw_spin_unlock(&rq->lock); 351 raw_spin_unlock_irqrestore(&p->pi_lock, *flags); 352 } 353} 354 355static void __task_rq_unlock(struct rq *rq) 356 __releases(rq->lock) 357{ 358 raw_spin_unlock(&rq->lock); 359} 360 361static inline void 362task_rq_unlock(struct rq *rq, struct task_struct *p, unsigned long *flags) 363 __releases(rq->lock) 364 __releases(p->pi_lock) 365{ 366 raw_spin_unlock(&rq->lock); 367 raw_spin_unlock_irqrestore(&p->pi_lock, *flags); 368} 369 370/* 371 * this_rq_lock - lock this runqueue and disable interrupts. 372 */ 373static struct rq *this_rq_lock(void) 374 __acquires(rq->lock) 375{ 376 struct rq *rq; 377 378 local_irq_disable(); 379 rq = this_rq(); 380 raw_spin_lock(&rq->lock); 381 382 return rq; 383} 384 385#ifdef CONFIG_SCHED_HRTICK 386/* 387 * Use HR-timers to deliver accurate preemption points. 388 */ 389 390static void hrtick_clear(struct rq *rq) 391{ 392 if (hrtimer_active(&rq->hrtick_timer)) 393 hrtimer_cancel(&rq->hrtick_timer); 394} 395 396/* 397 * High-resolution timer tick. 398 * Runs from hardirq context with interrupts disabled. 399 */ 400static enum hrtimer_restart hrtick(struct hrtimer *timer) 401{ 402 struct rq *rq = container_of(timer, struct rq, hrtick_timer); 403 404 WARN_ON_ONCE(cpu_of(rq) != smp_processor_id()); 405 406 raw_spin_lock(&rq->lock); 407 update_rq_clock(rq); 408 rq->curr->sched_class->task_tick(rq, rq->curr, 1); 409 raw_spin_unlock(&rq->lock); 410 411 return HRTIMER_NORESTART; 412} 413 414#ifdef CONFIG_SMP 415 416static int __hrtick_restart(struct rq *rq) 417{ 418 struct hrtimer *timer = &rq->hrtick_timer; 419 ktime_t time = hrtimer_get_softexpires(timer); 420 421 return __hrtimer_start_range_ns(timer, time, 0, HRTIMER_MODE_ABS_PINNED, 0); 422} 423 424/* 425 * called from hardirq (IPI) context 426 */ 427static void __hrtick_start(void *arg) 428{ 429 struct rq *rq = arg; 430 431 raw_spin_lock(&rq->lock); 432 __hrtick_restart(rq); 433 rq->hrtick_csd_pending = 0; 434 raw_spin_unlock(&rq->lock); 435} 436 437/* 438 * Called to set the hrtick timer state. 439 * 440 * called with rq->lock held and irqs disabled 441 */ 442void hrtick_start(struct rq *rq, u64 delay) 443{ 444 struct hrtimer *timer = &rq->hrtick_timer; 445 ktime_t time = ktime_add_ns(timer->base->get_time(), delay); 446 447 hrtimer_set_expires(timer, time); 448 449 if (rq == this_rq()) { 450 __hrtick_restart(rq); 451 } else if (!rq->hrtick_csd_pending) { 452 smp_call_function_single_async(cpu_of(rq), &rq->hrtick_csd); 453 rq->hrtick_csd_pending = 1; 454 } 455} 456 457static int 458hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu) 459{ 460 int cpu = (int)(long)hcpu; 461 462 switch (action) { 463 case CPU_UP_CANCELED: 464 case CPU_UP_CANCELED_FROZEN: 465 case CPU_DOWN_PREPARE: 466 case CPU_DOWN_PREPARE_FROZEN: 467 case CPU_DEAD: 468 case CPU_DEAD_FROZEN: 469 hrtick_clear(cpu_rq(cpu)); 470 return NOTIFY_OK; 471 } 472 473 return NOTIFY_DONE; 474} 475 476static __init void init_hrtick(void) 477{ 478 hotcpu_notifier(hotplug_hrtick, 0); 479} 480#else 481/* 482 * Called to set the hrtick timer state. 483 * 484 * called with rq->lock held and irqs disabled 485 */ 486void hrtick_start(struct rq *rq, u64 delay) 487{ 488 __hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0, 489 HRTIMER_MODE_REL_PINNED, 0); 490} 491 492static inline void init_hrtick(void) 493{ 494} 495#endif /* CONFIG_SMP */ 496 497static void init_rq_hrtick(struct rq *rq) 498{ 499#ifdef CONFIG_SMP 500 rq->hrtick_csd_pending = 0; 501 502 rq->hrtick_csd.flags = 0; 503 rq->hrtick_csd.func = __hrtick_start; 504 rq->hrtick_csd.info = rq; 505#endif 506 507 hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 508 rq->hrtick_timer.function = hrtick; 509} 510#else /* CONFIG_SCHED_HRTICK */ 511static inline void hrtick_clear(struct rq *rq) 512{ 513} 514 515static inline void init_rq_hrtick(struct rq *rq) 516{ 517} 518 519static inline void init_hrtick(void) 520{ 521} 522#endif /* CONFIG_SCHED_HRTICK */ 523 524/* 525 * cmpxchg based fetch_or, macro so it works for different integer types 526 */ 527#define fetch_or(ptr, val) \ 528({ typeof(*(ptr)) __old, __val = *(ptr); \ 529 for (;;) { \ 530 __old = cmpxchg((ptr), __val, __val | (val)); \ 531 if (__old == __val) \ 532 break; \ 533 __val = __old; \ 534 } \ 535 __old; \ 536}) 537 538#if defined(CONFIG_SMP) && defined(TIF_POLLING_NRFLAG) 539/* 540 * Atomically set TIF_NEED_RESCHED and test for TIF_POLLING_NRFLAG, 541 * this avoids any races wrt polling state changes and thereby avoids 542 * spurious IPIs. 543 */ 544static bool set_nr_and_not_polling(struct task_struct *p) 545{ 546 struct thread_info *ti = task_thread_info(p); 547 return !(fetch_or(&ti->flags, _TIF_NEED_RESCHED) & _TIF_POLLING_NRFLAG); 548} 549 550/* 551 * Atomically set TIF_NEED_RESCHED if TIF_POLLING_NRFLAG is set. 552 * 553 * If this returns true, then the idle task promises to call 554 * sched_ttwu_pending() and reschedule soon. 555 */ 556static bool set_nr_if_polling(struct task_struct *p) 557{ 558 struct thread_info *ti = task_thread_info(p); 559 typeof(ti->flags) old, val = ACCESS_ONCE(ti->flags); 560 561 for (;;) { 562 if (!(val & _TIF_POLLING_NRFLAG)) 563 return false; 564 if (val & _TIF_NEED_RESCHED) 565 return true; 566 old = cmpxchg(&ti->flags, val, val | _TIF_NEED_RESCHED); 567 if (old == val) 568 break; 569 val = old; 570 } 571 return true; 572} 573 574#else 575static bool set_nr_and_not_polling(struct task_struct *p) 576{ 577 set_tsk_need_resched(p); 578 return true; 579} 580 581#ifdef CONFIG_SMP 582static bool set_nr_if_polling(struct task_struct *p) 583{ 584 return false; 585} 586#endif 587#endif 588 589/* 590 * resched_task - mark a task 'to be rescheduled now'. 591 * 592 * On UP this means the setting of the need_resched flag, on SMP it 593 * might also involve a cross-CPU call to trigger the scheduler on 594 * the target CPU. 595 */ 596void resched_task(struct task_struct *p) 597{ 598 int cpu; 599 600 lockdep_assert_held(&task_rq(p)->lock); 601 602 if (test_tsk_need_resched(p)) 603 return; 604 605 cpu = task_cpu(p); 606 607 if (cpu == smp_processor_id()) { 608 set_tsk_need_resched(p); 609 set_preempt_need_resched(); 610 return; 611 } 612 613 if (set_nr_and_not_polling(p)) 614 smp_send_reschedule(cpu); 615 else 616 trace_sched_wake_idle_without_ipi(cpu); 617} 618 619void resched_cpu(int cpu) 620{ 621 struct rq *rq = cpu_rq(cpu); 622 unsigned long flags; 623 624 if (!raw_spin_trylock_irqsave(&rq->lock, flags)) 625 return; 626 resched_task(cpu_curr(cpu)); 627 raw_spin_unlock_irqrestore(&rq->lock, flags); 628} 629 630#ifdef CONFIG_SMP 631#ifdef CONFIG_NO_HZ_COMMON 632/* 633 * In the semi idle case, use the nearest busy cpu for migrating timers 634 * from an idle cpu. This is good for power-savings. 635 * 636 * We don't do similar optimization for completely idle system, as 637 * selecting an idle cpu will add more delays to the timers than intended 638 * (as that cpu's timer base may not be uptodate wrt jiffies etc). 639 */ 640int get_nohz_timer_target(int pinned) 641{ 642 int cpu = smp_processor_id(); 643 int i; 644 struct sched_domain *sd; 645 646 if (pinned || !get_sysctl_timer_migration() || !idle_cpu(cpu)) 647 return cpu; 648 649 rcu_read_lock(); 650 for_each_domain(cpu, sd) { 651 for_each_cpu(i, sched_domain_span(sd)) { 652 if (!idle_cpu(i)) { 653 cpu = i; 654 goto unlock; 655 } 656 } 657 } 658unlock: 659 rcu_read_unlock(); 660 return cpu; 661} 662/* 663 * When add_timer_on() enqueues a timer into the timer wheel of an 664 * idle CPU then this timer might expire before the next timer event 665 * which is scheduled to wake up that CPU. In case of a completely 666 * idle system the next event might even be infinite time into the 667 * future. wake_up_idle_cpu() ensures that the CPU is woken up and 668 * leaves the inner idle loop so the newly added timer is taken into 669 * account when the CPU goes back to idle and evaluates the timer 670 * wheel for the next timer event. 671 */ 672static void wake_up_idle_cpu(int cpu) 673{ 674 struct rq *rq = cpu_rq(cpu); 675 676 if (cpu == smp_processor_id()) 677 return; 678 679 if (set_nr_and_not_polling(rq->idle)) 680 smp_send_reschedule(cpu); 681 else 682 trace_sched_wake_idle_without_ipi(cpu); 683} 684 685static bool wake_up_full_nohz_cpu(int cpu) 686{ 687 if (tick_nohz_full_cpu(cpu)) { 688 if (cpu != smp_processor_id() || 689 tick_nohz_tick_stopped()) 690 smp_send_reschedule(cpu); 691 return true; 692 } 693 694 return false; 695} 696 697void wake_up_nohz_cpu(int cpu) 698{ 699 if (!wake_up_full_nohz_cpu(cpu)) 700 wake_up_idle_cpu(cpu); 701} 702 703static inline bool got_nohz_idle_kick(void) 704{ 705 int cpu = smp_processor_id(); 706 707 if (!test_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu))) 708 return false; 709 710 if (idle_cpu(cpu) && !need_resched()) 711 return true; 712 713 /* 714 * We can't run Idle Load Balance on this CPU for this time so we 715 * cancel it and clear NOHZ_BALANCE_KICK 716 */ 717 clear_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu)); 718 return false; 719} 720 721#else /* CONFIG_NO_HZ_COMMON */ 722 723static inline bool got_nohz_idle_kick(void) 724{ 725 return false; 726} 727 728#endif /* CONFIG_NO_HZ_COMMON */ 729 730#ifdef CONFIG_NO_HZ_FULL 731bool sched_can_stop_tick(void) 732{ 733 struct rq *rq; 734 735 rq = this_rq(); 736 737 /* Make sure rq->nr_running update is visible after the IPI */ 738 smp_rmb(); 739 740 /* More than one running task need preemption */ 741 if (rq->nr_running > 1) 742 return false; 743 744 return true; 745} 746#endif /* CONFIG_NO_HZ_FULL */ 747 748void sched_avg_update(struct rq *rq) 749{ 750 s64 period = sched_avg_period(); 751 752 while ((s64)(rq_clock(rq) - rq->age_stamp) > period) { 753 /* 754 * Inline assembly required to prevent the compiler 755 * optimising this loop into a divmod call. 756 * See __iter_div_u64_rem() for another example of this. 757 */ 758 asm("" : "+rm" (rq->age_stamp)); 759 rq->age_stamp += period; 760 rq->rt_avg /= 2; 761 } 762} 763 764#endif /* CONFIG_SMP */ 765 766#if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \ 767 (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH))) 768/* 769 * Iterate task_group tree rooted at *from, calling @down when first entering a 770 * node and @up when leaving it for the final time. 771 * 772 * Caller must hold rcu_lock or sufficient equivalent. 773 */ 774int walk_tg_tree_from(struct task_group *from, 775 tg_visitor down, tg_visitor up, void *data) 776{ 777 struct task_group *parent, *child; 778 int ret; 779 780 parent = from; 781 782down: 783 ret = (*down)(parent, data); 784 if (ret) 785 goto out; 786 list_for_each_entry_rcu(child, &parent->children, siblings) { 787 parent = child; 788 goto down; 789 790up: 791 continue; 792 } 793 ret = (*up)(parent, data); 794 if (ret || parent == from) 795 goto out; 796 797 child = parent; 798 parent = parent->parent; 799 if (parent) 800 goto up; 801out: 802 return ret; 803} 804 805int tg_nop(struct task_group *tg, void *data) 806{ 807 return 0; 808} 809#endif 810 811static void set_load_weight(struct task_struct *p) 812{ 813 int prio = p->static_prio - MAX_RT_PRIO; 814 struct load_weight *load = &p->se.load; 815 816 /* 817 * SCHED_IDLE tasks get minimal weight: 818 */ 819 if (p->policy == SCHED_IDLE) { 820 load->weight = scale_load(WEIGHT_IDLEPRIO); 821 load->inv_weight = WMULT_IDLEPRIO; 822 return; 823 } 824 825 load->weight = scale_load(prio_to_weight[prio]); 826 load->inv_weight = prio_to_wmult[prio]; 827} 828 829static void enqueue_task(struct rq *rq, struct task_struct *p, int flags) 830{ 831 update_rq_clock(rq); 832 sched_info_queued(rq, p); 833 p->sched_class->enqueue_task(rq, p, flags); 834} 835 836static void dequeue_task(struct rq *rq, struct task_struct *p, int flags) 837{ 838 update_rq_clock(rq); 839 sched_info_dequeued(rq, p); 840 p->sched_class->dequeue_task(rq, p, flags); 841} 842 843void activate_task(struct rq *rq, struct task_struct *p, int flags) 844{ 845 if (task_contributes_to_load(p)) 846 rq->nr_uninterruptible--; 847 848 enqueue_task(rq, p, flags); 849} 850 851void deactivate_task(struct rq *rq, struct task_struct *p, int flags) 852{ 853 if (task_contributes_to_load(p)) 854 rq->nr_uninterruptible++; 855 856 dequeue_task(rq, p, flags); 857} 858 859static void update_rq_clock_task(struct rq *rq, s64 delta) 860{ 861/* 862 * In theory, the compile should just see 0 here, and optimize out the call 863 * to sched_rt_avg_update. But I don't trust it... 864 */ 865#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) 866 s64 steal = 0, irq_delta = 0; 867#endif 868#ifdef CONFIG_IRQ_TIME_ACCOUNTING 869 irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time; 870 871 /* 872 * Since irq_time is only updated on {soft,}irq_exit, we might run into 873 * this case when a previous update_rq_clock() happened inside a 874 * {soft,}irq region. 875 * 876 * When this happens, we stop ->clock_task and only update the 877 * prev_irq_time stamp to account for the part that fit, so that a next 878 * update will consume the rest. This ensures ->clock_task is 879 * monotonic. 880 * 881 * It does however cause some slight miss-attribution of {soft,}irq 882 * time, a more accurate solution would be to update the irq_time using 883 * the current rq->clock timestamp, except that would require using 884 * atomic ops. 885 */ 886 if (irq_delta > delta) 887 irq_delta = delta; 888 889 rq->prev_irq_time += irq_delta; 890 delta -= irq_delta; 891#endif 892#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING 893 if (static_key_false((¶virt_steal_rq_enabled))) { 894 steal = paravirt_steal_clock(cpu_of(rq)); 895 steal -= rq->prev_steal_time_rq; 896 897 if (unlikely(steal > delta)) 898 steal = delta; 899 900 rq->prev_steal_time_rq += steal; 901 delta -= steal; 902 } 903#endif 904 905 rq->clock_task += delta; 906 907#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) 908 if ((irq_delta + steal) && sched_feat(NONTASK_CAPACITY)) 909 sched_rt_avg_update(rq, irq_delta + steal); 910#endif 911} 912 913void sched_set_stop_task(int cpu, struct task_struct *stop) 914{ 915 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 }; 916 struct task_struct *old_stop = cpu_rq(cpu)->stop; 917 918 if (stop) { 919 /* 920 * Make it appear like a SCHED_FIFO task, its something 921 * userspace knows about and won't get confused about. 922 * 923 * Also, it will make PI more or less work without too 924 * much confusion -- but then, stop work should not 925 * rely on PI working anyway. 926 */ 927 sched_setscheduler_nocheck(stop, SCHED_FIFO, ¶m); 928 929 stop->sched_class = &stop_sched_class; 930 } 931 932 cpu_rq(cpu)->stop = stop; 933 934 if (old_stop) { 935 /* 936 * Reset it back to a normal scheduling class so that 937 * it can die in pieces. 938 */ 939 old_stop->sched_class = &rt_sched_class; 940 } 941} 942 943/* 944 * __normal_prio - return the priority that is based on the static prio 945 */ 946static inline int __normal_prio(struct task_struct *p) 947{ 948 return p->static_prio; 949} 950 951/* 952 * Calculate the expected normal priority: i.e. priority 953 * without taking RT-inheritance into account. Might be 954 * boosted by interactivity modifiers. Changes upon fork, 955 * setprio syscalls, and whenever the interactivity 956 * estimator recalculates. 957 */ 958static inline int normal_prio(struct task_struct *p) 959{ 960 int prio; 961 962 if (task_has_dl_policy(p)) 963 prio = MAX_DL_PRIO-1; 964 else if (task_has_rt_policy(p)) 965 prio = MAX_RT_PRIO-1 - p->rt_priority; 966 else 967 prio = __normal_prio(p); 968 return prio; 969} 970 971/* 972 * Calculate the current priority, i.e. the priority 973 * taken into account by the scheduler. This value might 974 * be boosted by RT tasks, or might be boosted by 975 * interactivity modifiers. Will be RT if the task got 976 * RT-boosted. If not then it returns p->normal_prio. 977 */ 978static int effective_prio(struct task_struct *p) 979{ 980 p->normal_prio = normal_prio(p); 981 /* 982 * If we are RT tasks or we were boosted to RT priority, 983 * keep the priority unchanged. Otherwise, update priority 984 * to the normal priority: 985 */ 986 if (!rt_prio(p->prio)) 987 return p->normal_prio; 988 return p->prio; 989} 990 991/** 992 * task_curr - is this task currently executing on a CPU? 993 * @p: the task in question. 994 * 995 * Return: 1 if the task is currently executing. 0 otherwise. 996 */ 997inline int task_curr(const struct task_struct *p) 998{ 999 return cpu_curr(task_cpu(p)) == p; 1000} 1001 1002static inline void check_class_changed(struct rq *rq, struct task_struct *p, 1003 const struct sched_class *prev_class, 1004 int oldprio) 1005{ 1006 if (prev_class != p->sched_class) { 1007 if (prev_class->switched_from) 1008 prev_class->switched_from(rq, p); 1009 p->sched_class->switched_to(rq, p); 1010 } else if (oldprio != p->prio || dl_task(p)) 1011 p->sched_class->prio_changed(rq, p, oldprio); 1012} 1013 1014void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags) 1015{ 1016 const struct sched_class *class; 1017 1018 if (p->sched_class == rq->curr->sched_class) { 1019 rq->curr->sched_class->check_preempt_curr(rq, p, flags); 1020 } else { 1021 for_each_class(class) { 1022 if (class == rq->curr->sched_class) 1023 break; 1024 if (class == p->sched_class) { 1025 resched_task(rq->curr); 1026 break; 1027 } 1028 } 1029 } 1030 1031 /* 1032 * A queue event has occurred, and we're going to schedule. In 1033 * this case, we can save a useless back to back clock update. 1034 */ 1035 if (rq->curr->on_rq && test_tsk_need_resched(rq->curr)) 1036 rq->skip_clock_update = 1; 1037} 1038 1039#ifdef CONFIG_SMP 1040void set_task_cpu(struct task_struct *p, unsigned int new_cpu) 1041{ 1042#ifdef CONFIG_SCHED_DEBUG 1043 /* 1044 * We should never call set_task_cpu() on a blocked task, 1045 * ttwu() will sort out the placement. 1046 */ 1047 WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING && 1048 !(task_preempt_count(p) & PREEMPT_ACTIVE)); 1049 1050#ifdef CONFIG_LOCKDEP 1051 /* 1052 * The caller should hold either p->pi_lock or rq->lock, when changing 1053 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks. 1054 * 1055 * sched_move_task() holds both and thus holding either pins the cgroup, 1056 * see task_group(). 1057 * 1058 * Furthermore, all task_rq users should acquire both locks, see 1059 * task_rq_lock(). 1060 */ 1061 WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) || 1062 lockdep_is_held(&task_rq(p)->lock))); 1063#endif 1064#endif 1065 1066 trace_sched_migrate_task(p, new_cpu); 1067 1068 if (task_cpu(p) != new_cpu) { 1069 if (p->sched_class->migrate_task_rq) 1070 p->sched_class->migrate_task_rq(p, new_cpu); 1071 p->se.nr_migrations++; 1072 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, 1, NULL, 0); 1073 } 1074 1075 __set_task_cpu(p, new_cpu); 1076} 1077 1078static void __migrate_swap_task(struct task_struct *p, int cpu) 1079{ 1080 if (p->on_rq) { 1081 struct rq *src_rq, *dst_rq; 1082 1083 src_rq = task_rq(p); 1084 dst_rq = cpu_rq(cpu); 1085 1086 deactivate_task(src_rq, p, 0); 1087 set_task_cpu(p, cpu); 1088 activate_task(dst_rq, p, 0); 1089 check_preempt_curr(dst_rq, p, 0); 1090 } else { 1091 /* 1092 * Task isn't running anymore; make it appear like we migrated 1093 * it before it went to sleep. This means on wakeup we make the 1094 * previous cpu our targer instead of where it really is. 1095 */ 1096 p->wake_cpu = cpu; 1097 } 1098} 1099 1100struct migration_swap_arg { 1101 struct task_struct *src_task, *dst_task; 1102 int src_cpu, dst_cpu; 1103}; 1104 1105static int migrate_swap_stop(void *data) 1106{ 1107 struct migration_swap_arg *arg = data; 1108 struct rq *src_rq, *dst_rq; 1109 int ret = -EAGAIN; 1110 1111 src_rq = cpu_rq(arg->src_cpu); 1112 dst_rq = cpu_rq(arg->dst_cpu); 1113 1114 double_raw_lock(&arg->src_task->pi_lock, 1115 &arg->dst_task->pi_lock); 1116 double_rq_lock(src_rq, dst_rq); 1117 if (task_cpu(arg->dst_task) != arg->dst_cpu) 1118 goto unlock; 1119 1120 if (task_cpu(arg->src_task) != arg->src_cpu) 1121 goto unlock; 1122 1123 if (!cpumask_test_cpu(arg->dst_cpu, tsk_cpus_allowed(arg->src_task))) 1124 goto unlock; 1125 1126 if (!cpumask_test_cpu(arg->src_cpu, tsk_cpus_allowed(arg->dst_task))) 1127 goto unlock; 1128 1129 __migrate_swap_task(arg->src_task, arg->dst_cpu); 1130 __migrate_swap_task(arg->dst_task, arg->src_cpu); 1131 1132 ret = 0; 1133 1134unlock: 1135 double_rq_unlock(src_rq, dst_rq); 1136 raw_spin_unlock(&arg->dst_task->pi_lock); 1137 raw_spin_unlock(&arg->src_task->pi_lock); 1138 1139 return ret; 1140} 1141 1142/* 1143 * Cross migrate two tasks 1144 */ 1145int migrate_swap(struct task_struct *cur, struct task_struct *p) 1146{ 1147 struct migration_swap_arg arg; 1148 int ret = -EINVAL; 1149 1150 arg = (struct migration_swap_arg){ 1151 .src_task = cur, 1152 .src_cpu = task_cpu(cur), 1153 .dst_task = p, 1154 .dst_cpu = task_cpu(p), 1155 }; 1156 1157 if (arg.src_cpu == arg.dst_cpu) 1158 goto out; 1159 1160 /* 1161 * These three tests are all lockless; this is OK since all of them 1162 * will be re-checked with proper locks held further down the line. 1163 */ 1164 if (!cpu_active(arg.src_cpu) || !cpu_active(arg.dst_cpu)) 1165 goto out; 1166 1167 if (!cpumask_test_cpu(arg.dst_cpu, tsk_cpus_allowed(arg.src_task))) 1168 goto out; 1169 1170 if (!cpumask_test_cpu(arg.src_cpu, tsk_cpus_allowed(arg.dst_task))) 1171 goto out; 1172 1173 trace_sched_swap_numa(cur, arg.src_cpu, p, arg.dst_cpu); 1174 ret = stop_two_cpus(arg.dst_cpu, arg.src_cpu, migrate_swap_stop, &arg); 1175 1176out: 1177 return ret; 1178} 1179 1180struct migration_arg { 1181 struct task_struct *task; 1182 int dest_cpu; 1183}; 1184 1185static int migration_cpu_stop(void *data); 1186 1187/* 1188 * wait_task_inactive - wait for a thread to unschedule. 1189 * 1190 * If @match_state is nonzero, it's the @p->state value just checked and 1191 * not expected to change. If it changes, i.e. @p might have woken up, 1192 * then return zero. When we succeed in waiting for @p to be off its CPU, 1193 * we return a positive number (its total switch count). If a second call 1194 * a short while later returns the same number, the caller can be sure that 1195 * @p has remained unscheduled the whole time. 1196 * 1197 * The caller must ensure that the task *will* unschedule sometime soon, 1198 * else this function might spin for a *long* time. This function can't 1199 * be called with interrupts off, or it may introduce deadlock with 1200 * smp_call_function() if an IPI is sent by the same process we are 1201 * waiting to become inactive. 1202 */ 1203unsigned long wait_task_inactive(struct task_struct *p, long match_state) 1204{ 1205 unsigned long flags; 1206 int running, on_rq; 1207 unsigned long ncsw; 1208 struct rq *rq; 1209 1210 for (;;) { 1211 /* 1212 * We do the initial early heuristics without holding 1213 * any task-queue locks at all. We'll only try to get 1214 * the runqueue lock when things look like they will 1215 * work out! 1216 */ 1217 rq = task_rq(p); 1218 1219 /* 1220 * If the task is actively running on another CPU 1221 * still, just relax and busy-wait without holding 1222 * any locks. 1223 * 1224 * NOTE! Since we don't hold any locks, it's not 1225 * even sure that "rq" stays as the right runqueue! 1226 * But we don't care, since "task_running()" will 1227 * return false if the runqueue has changed and p 1228 * is actually now running somewhere else! 1229 */ 1230 while (task_running(rq, p)) { 1231 if (match_state && unlikely(p->state != match_state)) 1232 return 0; 1233 cpu_relax(); 1234 } 1235 1236 /* 1237 * Ok, time to look more closely! We need the rq 1238 * lock now, to be *sure*. If we're wrong, we'll 1239 * just go back and repeat. 1240 */ 1241 rq = task_rq_lock(p, &flags); 1242 trace_sched_wait_task(p); 1243 running = task_running(rq, p); 1244 on_rq = p->on_rq; 1245 ncsw = 0; 1246 if (!match_state || p->state == match_state) 1247 ncsw = p->nvcsw | LONG_MIN; /* sets MSB */ 1248 task_rq_unlock(rq, p, &flags); 1249 1250 /* 1251 * If it changed from the expected state, bail out now. 1252 */ 1253 if (unlikely(!ncsw)) 1254 break; 1255 1256 /* 1257 * Was it really running after all now that we 1258 * checked with the proper locks actually held? 1259 * 1260 * Oops. Go back and try again.. 1261 */ 1262 if (unlikely(running)) { 1263 cpu_relax(); 1264 continue; 1265 } 1266 1267 /* 1268 * It's not enough that it's not actively running, 1269 * it must be off the runqueue _entirely_, and not 1270 * preempted! 1271 * 1272 * So if it was still runnable (but just not actively 1273 * running right now), it's preempted, and we should 1274 * yield - it could be a while. 1275 */ 1276 if (unlikely(on_rq)) { 1277 ktime_t to = ktime_set(0, NSEC_PER_SEC/HZ); 1278 1279 set_current_state(TASK_UNINTERRUPTIBLE); 1280 schedule_hrtimeout(&to, HRTIMER_MODE_REL); 1281 continue; 1282 } 1283 1284 /* 1285 * Ahh, all good. It wasn't running, and it wasn't 1286 * runnable, which means that it will never become 1287 * running in the future either. We're all done! 1288 */ 1289 break; 1290 } 1291 1292 return ncsw; 1293} 1294 1295/*** 1296 * kick_process - kick a running thread to enter/exit the kernel 1297 * @p: the to-be-kicked thread 1298 * 1299 * Cause a process which is running on another CPU to enter 1300 * kernel-mode, without any delay. (to get signals handled.) 1301 * 1302 * NOTE: this function doesn't have to take the runqueue lock, 1303 * because all it wants to ensure is that the remote task enters 1304 * the kernel. If the IPI races and the task has been migrated 1305 * to another CPU then no harm is done and the purpose has been 1306 * achieved as well. 1307 */ 1308void kick_process(struct task_struct *p) 1309{ 1310 int cpu; 1311 1312 preempt_disable(); 1313 cpu = task_cpu(p); 1314 if ((cpu != smp_processor_id()) && task_curr(p)) 1315 smp_send_reschedule(cpu); 1316 preempt_enable(); 1317} 1318EXPORT_SYMBOL_GPL(kick_process); 1319#endif /* CONFIG_SMP */ 1320 1321#ifdef CONFIG_SMP 1322/* 1323 * ->cpus_allowed is protected by both rq->lock and p->pi_lock 1324 */ 1325static int select_fallback_rq(int cpu, struct task_struct *p) 1326{ 1327 int nid = cpu_to_node(cpu); 1328 const struct cpumask *nodemask = NULL; 1329 enum { cpuset, possible, fail } state = cpuset; 1330 int dest_cpu; 1331 1332 /* 1333 * If the node that the cpu is on has been offlined, cpu_to_node() 1334 * will return -1. There is no cpu on the node, and we should 1335 * select the cpu on the other node. 1336 */ 1337 if (nid != -1) { 1338 nodemask = cpumask_of_node(nid); 1339 1340 /* Look for allowed, online CPU in same node. */ 1341 for_each_cpu(dest_cpu, nodemask) { 1342 if (!cpu_online(dest_cpu)) 1343 continue; 1344 if (!cpu_active(dest_cpu)) 1345 continue; 1346 if (cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) 1347 return dest_cpu; 1348 } 1349 } 1350 1351 for (;;) { 1352 /* Any allowed, online CPU? */ 1353 for_each_cpu(dest_cpu, tsk_cpus_allowed(p)) { 1354 if (!cpu_online(dest_cpu)) 1355 continue; 1356 if (!cpu_active(dest_cpu)) 1357 continue; 1358 goto out; 1359 } 1360 1361 switch (state) { 1362 case cpuset: 1363 /* No more Mr. Nice Guy. */ 1364 cpuset_cpus_allowed_fallback(p); 1365 state = possible; 1366 break; 1367 1368 case possible: 1369 do_set_cpus_allowed(p, cpu_possible_mask); 1370 state = fail; 1371 break; 1372 1373 case fail: 1374 BUG(); 1375 break; 1376 } 1377 } 1378 1379out: 1380 if (state != cpuset) { 1381 /* 1382 * Don't tell them about moving exiting tasks or 1383 * kernel threads (both mm NULL), since they never 1384 * leave kernel. 1385 */ 1386 if (p->mm && printk_ratelimit()) { 1387 printk_deferred("process %d (%s) no longer affine to cpu%d\n", 1388 task_pid_nr(p), p->comm, cpu); 1389 } 1390 } 1391 1392 return dest_cpu; 1393} 1394 1395/* 1396 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable. 1397 */ 1398static inline 1399int select_task_rq(struct task_struct *p, int cpu, int sd_flags, int wake_flags) 1400{ 1401 cpu = p->sched_class->select_task_rq(p, cpu, sd_flags, wake_flags); 1402 1403 /* 1404 * In order not to call set_task_cpu() on a blocking task we need 1405 * to rely on ttwu() to place the task on a valid ->cpus_allowed 1406 * cpu. 1407 * 1408 * Since this is common to all placement strategies, this lives here. 1409 * 1410 * [ this allows ->select_task() to simply return task_cpu(p) and 1411 * not worry about this generic constraint ] 1412 */ 1413 if (unlikely(!cpumask_test_cpu(cpu, tsk_cpus_allowed(p)) || 1414 !cpu_online(cpu))) 1415 cpu = select_fallback_rq(task_cpu(p), p); 1416 1417 return cpu; 1418} 1419 1420static void update_avg(u64 *avg, u64 sample) 1421{ 1422 s64 diff = sample - *avg; 1423 *avg += diff >> 3; 1424} 1425#endif 1426 1427static void 1428ttwu_stat(struct task_struct *p, int cpu, int wake_flags) 1429{ 1430#ifdef CONFIG_SCHEDSTATS 1431 struct rq *rq = this_rq(); 1432 1433#ifdef CONFIG_SMP 1434 int this_cpu = smp_processor_id(); 1435 1436 if (cpu == this_cpu) { 1437 schedstat_inc(rq, ttwu_local); 1438 schedstat_inc(p, se.statistics.nr_wakeups_local); 1439 } else { 1440 struct sched_domain *sd; 1441 1442 schedstat_inc(p, se.statistics.nr_wakeups_remote); 1443 rcu_read_lock(); 1444 for_each_domain(this_cpu, sd) { 1445 if (cpumask_test_cpu(cpu, sched_domain_span(sd))) { 1446 schedstat_inc(sd, ttwu_wake_remote); 1447 break; 1448 } 1449 } 1450 rcu_read_unlock(); 1451 } 1452 1453 if (wake_flags & WF_MIGRATED) 1454 schedstat_inc(p, se.statistics.nr_wakeups_migrate); 1455 1456#endif /* CONFIG_SMP */ 1457 1458 schedstat_inc(rq, ttwu_count); 1459 schedstat_inc(p, se.statistics.nr_wakeups); 1460 1461 if (wake_flags & WF_SYNC) 1462 schedstat_inc(p, se.statistics.nr_wakeups_sync); 1463 1464#endif /* CONFIG_SCHEDSTATS */ 1465} 1466 1467static void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags) 1468{ 1469 activate_task(rq, p, en_flags); 1470 p->on_rq = 1; 1471 1472 /* if a worker is waking up, notify workqueue */ 1473 if (p->flags & PF_WQ_WORKER) 1474 wq_worker_waking_up(p, cpu_of(rq)); 1475} 1476 1477/* 1478 * Mark the task runnable and perform wakeup-preemption. 1479 */ 1480static void 1481ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags) 1482{ 1483 check_preempt_curr(rq, p, wake_flags); 1484 trace_sched_wakeup(p, true); 1485 1486 p->state = TASK_RUNNING; 1487#ifdef CONFIG_SMP 1488 if (p->sched_class->task_woken) 1489 p->sched_class->task_woken(rq, p); 1490 1491 if (rq->idle_stamp) { 1492 u64 delta = rq_clock(rq) - rq->idle_stamp; 1493 u64 max = 2*rq->max_idle_balance_cost; 1494 1495 update_avg(&rq->avg_idle, delta); 1496 1497 if (rq->avg_idle > max) 1498 rq->avg_idle = max; 1499 1500 rq->idle_stamp = 0; 1501 } 1502#endif 1503} 1504 1505static void 1506ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags) 1507{ 1508#ifdef CONFIG_SMP 1509 if (p->sched_contributes_to_load) 1510 rq->nr_uninterruptible--; 1511#endif 1512 1513 ttwu_activate(rq, p, ENQUEUE_WAKEUP | ENQUEUE_WAKING); 1514 ttwu_do_wakeup(rq, p, wake_flags); 1515} 1516 1517/* 1518 * Called in case the task @p isn't fully descheduled from its runqueue, 1519 * in this case we must do a remote wakeup. Its a 'light' wakeup though, 1520 * since all we need to do is flip p->state to TASK_RUNNING, since 1521 * the task is still ->on_rq. 1522 */ 1523static int ttwu_remote(struct task_struct *p, int wake_flags) 1524{ 1525 struct rq *rq; 1526 int ret = 0; 1527 1528 rq = __task_rq_lock(p); 1529 if (p->on_rq) { 1530 /* check_preempt_curr() may use rq clock */ 1531 update_rq_clock(rq); 1532 ttwu_do_wakeup(rq, p, wake_flags); 1533 ret = 1; 1534 } 1535 __task_rq_unlock(rq); 1536 1537 return ret; 1538} 1539 1540#ifdef CONFIG_SMP 1541void sched_ttwu_pending(void) 1542{ 1543 struct rq *rq = this_rq(); 1544 struct llist_node *llist = llist_del_all(&rq->wake_list); 1545 struct task_struct *p; 1546 unsigned long flags; 1547 1548 if (!llist) 1549 return; 1550 1551 raw_spin_lock_irqsave(&rq->lock, flags); 1552 1553 while (llist) { 1554 p = llist_entry(llist, struct task_struct, wake_entry); 1555 llist = llist_next(llist); 1556 ttwu_do_activate(rq, p, 0); 1557 } 1558 1559 raw_spin_unlock_irqrestore(&rq->lock, flags); 1560} 1561 1562void scheduler_ipi(void) 1563{ 1564 /* 1565 * Fold TIF_NEED_RESCHED into the preempt_count; anybody setting 1566 * TIF_NEED_RESCHED remotely (for the first time) will also send 1567 * this IPI. 1568 */ 1569 preempt_fold_need_resched(); 1570 1571 if (llist_empty(&this_rq()->wake_list) 1572 && !tick_nohz_full_cpu(smp_processor_id()) 1573 && !got_nohz_idle_kick()) 1574 return; 1575 1576 /* 1577 * Not all reschedule IPI handlers call irq_enter/irq_exit, since 1578 * traditionally all their work was done from the interrupt return 1579 * path. Now that we actually do some work, we need to make sure 1580 * we do call them. 1581 * 1582 * Some archs already do call them, luckily irq_enter/exit nest 1583 * properly. 1584 * 1585 * Arguably we should visit all archs and update all handlers, 1586 * however a fair share of IPIs are still resched only so this would 1587 * somewhat pessimize the simple resched case. 1588 */ 1589 irq_enter(); 1590 tick_nohz_full_check(); 1591 sched_ttwu_pending(); 1592 1593 /* 1594 * Check if someone kicked us for doing the nohz idle load balance. 1595 */ 1596 if (unlikely(got_nohz_idle_kick())) { 1597 this_rq()->idle_balance = 1; 1598 raise_softirq_irqoff(SCHED_SOFTIRQ); 1599 } 1600 irq_exit(); 1601} 1602 1603static void ttwu_queue_remote(struct task_struct *p, int cpu) 1604{ 1605 struct rq *rq = cpu_rq(cpu); 1606 1607 if (llist_add(&p->wake_entry, &cpu_rq(cpu)->wake_list)) { 1608 if (!set_nr_if_polling(rq->idle)) 1609 smp_send_reschedule(cpu); 1610 else 1611 trace_sched_wake_idle_without_ipi(cpu); 1612 } 1613} 1614 1615bool cpus_share_cache(int this_cpu, int that_cpu) 1616{ 1617 return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu); 1618} 1619#endif /* CONFIG_SMP */ 1620 1621static void ttwu_queue(struct task_struct *p, int cpu) 1622{ 1623 struct rq *rq = cpu_rq(cpu); 1624 1625#if defined(CONFIG_SMP) 1626 if (sched_feat(TTWU_QUEUE) && !cpus_share_cache(smp_processor_id(), cpu)) { 1627 sched_clock_cpu(cpu); /* sync clocks x-cpu */ 1628 ttwu_queue_remote(p, cpu); 1629 return; 1630 } 1631#endif 1632 1633 raw_spin_lock(&rq->lock); 1634 ttwu_do_activate(rq, p, 0); 1635 raw_spin_unlock(&rq->lock); 1636} 1637 1638/** 1639 * try_to_wake_up - wake up a thread 1640 * @p: the thread to be awakened 1641 * @state: the mask of task states that can be woken 1642 * @wake_flags: wake modifier flags (WF_*) 1643 * 1644 * Put it on the run-queue if it's not already there. The "current" 1645 * thread is always on the run-queue (except when the actual 1646 * re-schedule is in progress), and as such you're allowed to do 1647 * the simpler "current->state = TASK_RUNNING" to mark yourself 1648 * runnable without the overhead of this. 1649 * 1650 * Return: %true if @p was woken up, %false if it was already running. 1651 * or @state didn't match @p's state. 1652 */ 1653static int 1654try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) 1655{ 1656 unsigned long flags; 1657 int cpu, success = 0; 1658 1659 /* 1660 * If we are going to wake up a thread waiting for CONDITION we 1661 * need to ensure that CONDITION=1 done by the caller can not be 1662 * reordered with p->state check below. This pairs with mb() in 1663 * set_current_state() the waiting thread does. 1664 */ 1665 smp_mb__before_spinlock(); 1666 raw_spin_lock_irqsave(&p->pi_lock, flags); 1667 if (!(p->state & state)) 1668 goto out; 1669 1670 success = 1; /* we're going to change ->state */ 1671 cpu = task_cpu(p); 1672 1673 if (p->on_rq && ttwu_remote(p, wake_flags)) 1674 goto stat; 1675 1676#ifdef CONFIG_SMP 1677 /* 1678 * If the owning (remote) cpu is still in the middle of schedule() with 1679 * this task as prev, wait until its done referencing the task. 1680 */ 1681 while (p->on_cpu) 1682 cpu_relax(); 1683 /* 1684 * Pairs with the smp_wmb() in finish_lock_switch(). 1685 */ 1686 smp_rmb(); 1687 1688 p->sched_contributes_to_load = !!task_contributes_to_load(p); 1689 p->state = TASK_WAKING; 1690 1691 if (p->sched_class->task_waking) 1692 p->sched_class->task_waking(p); 1693 1694 cpu = select_task_rq(p, p->wake_cpu, SD_BALANCE_WAKE, wake_flags); 1695 if (task_cpu(p) != cpu) { 1696 wake_flags |= WF_MIGRATED; 1697 set_task_cpu(p, cpu); 1698 } 1699#endif /* CONFIG_SMP */ 1700 1701 ttwu_queue(p, cpu); 1702stat: 1703 ttwu_stat(p, cpu, wake_flags); 1704out: 1705 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 1706 1707 return success; 1708} 1709 1710/** 1711 * try_to_wake_up_local - try to wake up a local task with rq lock held 1712 * @p: the thread to be awakened 1713 * 1714 * Put @p on the run-queue if it's not already there. The caller must 1715 * ensure that this_rq() is locked, @p is bound to this_rq() and not 1716 * the current task. 1717 */ 1718static void try_to_wake_up_local(struct task_struct *p) 1719{ 1720 struct rq *rq = task_rq(p); 1721 1722 if (WARN_ON_ONCE(rq != this_rq()) || 1723 WARN_ON_ONCE(p == current)) 1724 return; 1725 1726 lockdep_assert_held(&rq->lock); 1727 1728 if (!raw_spin_trylock(&p->pi_lock)) { 1729 raw_spin_unlock(&rq->lock); 1730 raw_spin_lock(&p->pi_lock); 1731 raw_spin_lock(&rq->lock); 1732 } 1733 1734 if (!(p->state & TASK_NORMAL)) 1735 goto out; 1736 1737 if (!p->on_rq) 1738 ttwu_activate(rq, p, ENQUEUE_WAKEUP); 1739 1740 ttwu_do_wakeup(rq, p, 0); 1741 ttwu_stat(p, smp_processor_id(), 0); 1742out: 1743 raw_spin_unlock(&p->pi_lock); 1744} 1745 1746/** 1747 * wake_up_process - Wake up a specific process 1748 * @p: The process to be woken up. 1749 * 1750 * Attempt to wake up the nominated process and move it to the set of runnable 1751 * processes. 1752 * 1753 * Return: 1 if the process was woken up, 0 if it was already running. 1754 * 1755 * It may be assumed that this function implies a write memory barrier before 1756 * changing the task state if and only if any tasks are woken up. 1757 */ 1758int wake_up_process(struct task_struct *p) 1759{ 1760 WARN_ON(task_is_stopped_or_traced(p)); 1761 return try_to_wake_up(p, TASK_NORMAL, 0); 1762} 1763EXPORT_SYMBOL(wake_up_process); 1764 1765int wake_up_state(struct task_struct *p, unsigned int state) 1766{ 1767 return try_to_wake_up(p, state, 0); 1768} 1769 1770/* 1771 * Perform scheduler related setup for a newly forked process p. 1772 * p is forked by current. 1773 * 1774 * __sched_fork() is basic setup used by init_idle() too: 1775 */ 1776static void __sched_fork(unsigned long clone_flags, struct task_struct *p) 1777{ 1778 p->on_rq = 0; 1779 1780 p->se.on_rq = 0; 1781 p->se.exec_start = 0; 1782 p->se.sum_exec_runtime = 0; 1783 p->se.prev_sum_exec_runtime = 0; 1784 p->se.nr_migrations = 0; 1785 p->se.vruntime = 0; 1786 INIT_LIST_HEAD(&p->se.group_node); 1787 1788#ifdef CONFIG_SCHEDSTATS 1789 memset(&p->se.statistics, 0, sizeof(p->se.statistics)); 1790#endif 1791 1792 RB_CLEAR_NODE(&p->dl.rb_node); 1793 hrtimer_init(&p->dl.dl_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 1794 p->dl.dl_runtime = p->dl.runtime = 0; 1795 p->dl.dl_deadline = p->dl.deadline = 0; 1796 p->dl.dl_period = 0; 1797 p->dl.flags = 0; 1798 1799 INIT_LIST_HEAD(&p->rt.run_list); 1800 1801#ifdef CONFIG_PREEMPT_NOTIFIERS 1802 INIT_HLIST_HEAD(&p->preempt_notifiers); 1803#endif 1804 1805#ifdef CONFIG_NUMA_BALANCING 1806 if (p->mm && atomic_read(&p->mm->mm_users) == 1) { 1807 p->mm->numa_next_scan = jiffies + msecs_to_jiffies(sysctl_numa_balancing_scan_delay); 1808 p->mm->numa_scan_seq = 0; 1809 } 1810 1811 if (clone_flags & CLONE_VM) 1812 p->numa_preferred_nid = current->numa_preferred_nid; 1813 else 1814 p->numa_preferred_nid = -1; 1815 1816 p->node_stamp = 0ULL; 1817 p->numa_scan_seq = p->mm ? p->mm->numa_scan_seq : 0; 1818 p->numa_scan_period = sysctl_numa_balancing_scan_delay; 1819 p->numa_work.next = &p->numa_work; 1820 p->numa_faults_memory = NULL; 1821 p->numa_faults_buffer_memory = NULL; 1822 p->last_task_numa_placement = 0; 1823 p->last_sum_exec_runtime = 0; 1824 1825 INIT_LIST_HEAD(&p->numa_entry); 1826 p->numa_group = NULL; 1827#endif /* CONFIG_NUMA_BALANCING */ 1828} 1829 1830#ifdef CONFIG_NUMA_BALANCING 1831#ifdef CONFIG_SCHED_DEBUG 1832void set_numabalancing_state(bool enabled) 1833{ 1834 if (enabled) 1835 sched_feat_set("NUMA"); 1836 else 1837 sched_feat_set("NO_NUMA"); 1838} 1839#else 1840__read_mostly bool numabalancing_enabled; 1841 1842void set_numabalancing_state(bool enabled) 1843{ 1844 numabalancing_enabled = enabled; 1845} 1846#endif /* CONFIG_SCHED_DEBUG */ 1847 1848#ifdef CONFIG_PROC_SYSCTL 1849int sysctl_numa_balancing(struct ctl_table *table, int write, 1850 void __user *buffer, size_t *lenp, loff_t *ppos) 1851{ 1852 struct ctl_table t; 1853 int err; 1854 int state = numabalancing_enabled; 1855 1856 if (write && !capable(CAP_SYS_ADMIN)) 1857 return -EPERM; 1858 1859 t = *table; 1860 t.data = &state; 1861 err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos); 1862 if (err < 0) 1863 return err; 1864 if (write) 1865 set_numabalancing_state(state); 1866 return err; 1867} 1868#endif 1869#endif 1870 1871/* 1872 * fork()/clone()-time setup: 1873 */ 1874int sched_fork(unsigned long clone_flags, struct task_struct *p) 1875{ 1876 unsigned long flags; 1877 int cpu = get_cpu(); 1878 1879 __sched_fork(clone_flags, p); 1880 /* 1881 * We mark the process as running here. This guarantees that 1882 * nobody will actually run it, and a signal or other external 1883 * event cannot wake it up and insert it on the runqueue either. 1884 */ 1885 p->state = TASK_RUNNING; 1886 1887 /* 1888 * Make sure we do not leak PI boosting priority to the child. 1889 */ 1890 p->prio = current->normal_prio; 1891 1892 /* 1893 * Revert to default priority/policy on fork if requested. 1894 */ 1895 if (unlikely(p->sched_reset_on_fork)) { 1896 if (task_has_dl_policy(p) || task_has_rt_policy(p)) { 1897 p->policy = SCHED_NORMAL; 1898 p->static_prio = NICE_TO_PRIO(0); 1899 p->rt_priority = 0; 1900 } else if (PRIO_TO_NICE(p->static_prio) < 0) 1901 p->static_prio = NICE_TO_PRIO(0); 1902 1903 p->prio = p->normal_prio = __normal_prio(p); 1904 set_load_weight(p); 1905 1906 /* 1907 * We don't need the reset flag anymore after the fork. It has 1908 * fulfilled its duty: 1909 */ 1910 p->sched_reset_on_fork = 0; 1911 } 1912 1913 if (dl_prio(p->prio)) { 1914 put_cpu(); 1915 return -EAGAIN; 1916 } else if (rt_prio(p->prio)) { 1917 p->sched_class = &rt_sched_class; 1918 } else { 1919 p->sched_class = &fair_sched_class; 1920 } 1921 1922 if (p->sched_class->task_fork) 1923 p->sched_class->task_fork(p); 1924 1925 /* 1926 * The child is not yet in the pid-hash so no cgroup attach races, 1927 * and the cgroup is pinned to this child due to cgroup_fork() 1928 * is ran before sched_fork(). 1929 * 1930 * Silence PROVE_RCU. 1931 */ 1932 raw_spin_lock_irqsave(&p->pi_lock, flags); 1933 set_task_cpu(p, cpu); 1934 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 1935 1936#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) 1937 if (likely(sched_info_on())) 1938 memset(&p->sched_info, 0, sizeof(p->sched_info)); 1939#endif 1940#if defined(CONFIG_SMP) 1941 p->on_cpu = 0; 1942#endif 1943 init_task_preempt_count(p); 1944#ifdef CONFIG_SMP 1945 plist_node_init(&p->pushable_tasks, MAX_PRIO); 1946 RB_CLEAR_NODE(&p->pushable_dl_tasks); 1947#endif 1948 1949 put_cpu(); 1950 return 0; 1951} 1952 1953unsigned long to_ratio(u64 period, u64 runtime) 1954{ 1955 if (runtime == RUNTIME_INF) 1956 return 1ULL << 20; 1957 1958 /* 1959 * Doing this here saves a lot of checks in all 1960 * the calling paths, and returning zero seems 1961 * safe for them anyway. 1962 */ 1963 if (period == 0) 1964 return 0; 1965 1966 return div64_u64(runtime << 20, period); 1967} 1968 1969#ifdef CONFIG_SMP 1970inline struct dl_bw *dl_bw_of(int i) 1971{ 1972 return &cpu_rq(i)->rd->dl_bw; 1973} 1974 1975static inline int dl_bw_cpus(int i) 1976{ 1977 struct root_domain *rd = cpu_rq(i)->rd; 1978 int cpus = 0; 1979 1980 for_each_cpu_and(i, rd->span, cpu_active_mask) 1981 cpus++; 1982 1983 return cpus; 1984} 1985#else 1986inline struct dl_bw *dl_bw_of(int i) 1987{ 1988 return &cpu_rq(i)->dl.dl_bw; 1989} 1990 1991static inline int dl_bw_cpus(int i) 1992{ 1993 return 1; 1994} 1995#endif 1996 1997static inline 1998void __dl_clear(struct dl_bw *dl_b, u64 tsk_bw) 1999{ 2000 dl_b->total_bw -= tsk_bw; 2001} 2002 2003static inline 2004void __dl_add(struct dl_bw *dl_b, u64 tsk_bw) 2005{ 2006 dl_b->total_bw += tsk_bw; 2007} 2008 2009static inline 2010bool __dl_overflow(struct dl_bw *dl_b, int cpus, u64 old_bw, u64 new_bw) 2011{ 2012 return dl_b->bw != -1 && 2013 dl_b->bw * cpus < dl_b->total_bw - old_bw + new_bw; 2014} 2015 2016/* 2017 * We must be sure that accepting a new task (or allowing changing the 2018 * parameters of an existing one) is consistent with the bandwidth 2019 * constraints. If yes, this function also accordingly updates the currently 2020 * allocated bandwidth to reflect the new situation. 2021 * 2022 * This function is called while holding p's rq->lock. 2023 */ 2024static int dl_overflow(struct task_struct *p, int policy, 2025 const struct sched_attr *attr) 2026{ 2027 2028 struct dl_bw *dl_b = dl_bw_of(task_cpu(p)); 2029 u64 period = attr->sched_period ?: attr->sched_deadline; 2030 u64 runtime = attr->sched_runtime; 2031 u64 new_bw = dl_policy(policy) ? to_ratio(period, runtime) : 0; 2032 int cpus, err = -1; 2033 2034 if (new_bw == p->dl.dl_bw) 2035 return 0; 2036 2037 /* 2038 * Either if a task, enters, leave, or stays -deadline but changes 2039 * its parameters, we may need to update accordingly the total 2040 * allocated bandwidth of the container. 2041 */ 2042 raw_spin_lock(&dl_b->lock); 2043 cpus = dl_bw_cpus(task_cpu(p)); 2044 if (dl_policy(policy) && !task_has_dl_policy(p) && 2045 !__dl_overflow(dl_b, cpus, 0, new_bw)) { 2046 __dl_add(dl_b, new_bw); 2047 err = 0; 2048 } else if (dl_policy(policy) && task_has_dl_policy(p) && 2049 !__dl_overflow(dl_b, cpus, p->dl.dl_bw, new_bw)) { 2050 __dl_clear(dl_b, p->dl.dl_bw); 2051 __dl_add(dl_b, new_bw); 2052 err = 0; 2053 } else if (!dl_policy(policy) && task_has_dl_policy(p)) { 2054 __dl_clear(dl_b, p->dl.dl_bw); 2055 err = 0; 2056 } 2057 raw_spin_unlock(&dl_b->lock); 2058 2059 return err; 2060} 2061 2062extern void init_dl_bw(struct dl_bw *dl_b); 2063 2064/* 2065 * wake_up_new_task - wake up a newly created task for the first time. 2066 * 2067 * This function will do some initial scheduler statistics housekeeping 2068 * that must be done for every newly created context, then puts the task 2069 * on the runqueue and wakes it. 2070 */ 2071void wake_up_new_task(struct task_struct *p) 2072{ 2073 unsigned long flags; 2074 struct rq *rq; 2075 2076 raw_spin_lock_irqsave(&p->pi_lock, flags); 2077#ifdef CONFIG_SMP 2078 /* 2079 * Fork balancing, do it here and not earlier because: 2080 * - cpus_allowed can change in the fork path 2081 * - any previously selected cpu might disappear through hotplug 2082 */ 2083 set_task_cpu(p, select_task_rq(p, task_cpu(p), SD_BALANCE_FORK, 0)); 2084#endif 2085 2086 /* Initialize new task's runnable average */ 2087 init_task_runnable_average(p); 2088 rq = __task_rq_lock(p); 2089 activate_task(rq, p, 0); 2090 p->on_rq = 1; 2091 trace_sched_wakeup_new(p, true); 2092 check_preempt_curr(rq, p, WF_FORK); 2093#ifdef CONFIG_SMP 2094 if (p->sched_class->task_woken) 2095 p->sched_class->task_woken(rq, p); 2096#endif 2097 task_rq_unlock(rq, p, &flags); 2098} 2099 2100#ifdef CONFIG_PREEMPT_NOTIFIERS 2101 2102/** 2103 * preempt_notifier_register - tell me when current is being preempted & rescheduled 2104 * @notifier: notifier struct to register 2105 */ 2106void preempt_notifier_register(struct preempt_notifier *notifier) 2107{ 2108 hlist_add_head(¬ifier->link, ¤t->preempt_notifiers); 2109} 2110EXPORT_SYMBOL_GPL(preempt_notifier_register); 2111 2112/** 2113 * preempt_notifier_unregister - no longer interested in preemption notifications 2114 * @notifier: notifier struct to unregister 2115 * 2116 * This is safe to call from within a preemption notifier. 2117 */ 2118void preempt_notifier_unregister(struct preempt_notifier *notifier) 2119{ 2120 hlist_del(¬ifier->link); 2121} 2122EXPORT_SYMBOL_GPL(preempt_notifier_unregister); 2123 2124static void fire_sched_in_preempt_notifiers(struct task_struct *curr) 2125{ 2126 struct preempt_notifier *notifier; 2127 2128 hlist_for_each_entry(notifier, &curr->preempt_notifiers, link) 2129 notifier->ops->sched_in(notifier, raw_smp_processor_id()); 2130} 2131 2132static void 2133fire_sched_out_preempt_notifiers(struct task_struct *curr, 2134 struct task_struct *next) 2135{ 2136 struct preempt_notifier *notifier; 2137 2138 hlist_for_each_entry(notifier, &curr->preempt_notifiers, link) 2139 notifier->ops->sched_out(notifier, next); 2140} 2141 2142#else /* !CONFIG_PREEMPT_NOTIFIERS */ 2143 2144static void fire_sched_in_preempt_notifiers(struct task_struct *curr) 2145{ 2146} 2147 2148static void 2149fire_sched_out_preempt_notifiers(struct task_struct *curr, 2150 struct task_struct *next) 2151{ 2152} 2153 2154#endif /* CONFIG_PREEMPT_NOTIFIERS */ 2155 2156/** 2157 * prepare_task_switch - prepare to switch tasks 2158 * @rq: the runqueue preparing to switch 2159 * @prev: the current task that is being switched out 2160 * @next: the task we are going to switch to. 2161 * 2162 * This is called with the rq lock held and interrupts off. It must 2163 * be paired with a subsequent finish_task_switch after the context 2164 * switch. 2165 * 2166 * prepare_task_switch sets up locking and calls architecture specific 2167 * hooks. 2168 */ 2169static inline void 2170prepare_task_switch(struct rq *rq, struct task_struct *prev, 2171 struct task_struct *next) 2172{ 2173 trace_sched_switch(prev, next); 2174 sched_info_switch(rq, prev, next); 2175 perf_event_task_sched_out(prev, next); 2176 fire_sched_out_preempt_notifiers(prev, next); 2177 prepare_lock_switch(rq, next); 2178 prepare_arch_switch(next); 2179} 2180 2181/** 2182 * finish_task_switch - clean up after a task-switch 2183 * @rq: runqueue associated with task-switch 2184 * @prev: the thread we just switched away from. 2185 * 2186 * finish_task_switch must be called after the context switch, paired 2187 * with a prepare_task_switch call before the context switch. 2188 * finish_task_switch will reconcile locking set up by prepare_task_switch, 2189 * and do any other architecture-specific cleanup actions. 2190 * 2191 * Note that we may have delayed dropping an mm in context_switch(). If 2192 * so, we finish that here outside of the runqueue lock. (Doing it 2193 * with the lock held can cause deadlocks; see schedule() for 2194 * details.) 2195 */ 2196static void finish_task_switch(struct rq *rq, struct task_struct *prev) 2197 __releases(rq->lock) 2198{ 2199 struct mm_struct *mm = rq->prev_mm; 2200 long prev_state; 2201 2202 rq->prev_mm = NULL; 2203 2204 /* 2205 * A task struct has one reference for the use as "current". 2206 * If a task dies, then it sets TASK_DEAD in tsk->state and calls 2207 * schedule one last time. The schedule call will never return, and 2208 * the scheduled task must drop that reference. 2209 * The test for TASK_DEAD must occur while the runqueue locks are 2210 * still held, otherwise prev could be scheduled on another cpu, die 2211 * there before we look at prev->state, and then the reference would 2212 * be dropped twice. 2213 * Manfred Spraul <manfred@colorfullife.com> 2214 */ 2215 prev_state = prev->state; 2216 vtime_task_switch(prev); 2217 finish_arch_switch(prev); 2218 perf_event_task_sched_in(prev, current); 2219 finish_lock_switch(rq, prev); 2220 finish_arch_post_lock_switch(); 2221 2222 fire_sched_in_preempt_notifiers(current); 2223 if (mm) 2224 mmdrop(mm); 2225 if (unlikely(prev_state == TASK_DEAD)) { 2226 if (prev->sched_class->task_dead) 2227 prev->sched_class->task_dead(prev); 2228 2229 /* 2230 * Remove function-return probe instances associated with this 2231 * task and put them back on the free list. 2232 */ 2233 kprobe_flush_task(prev); 2234 put_task_struct(prev); 2235 } 2236 2237 tick_nohz_task_switch(current); 2238} 2239 2240#ifdef CONFIG_SMP 2241 2242/* rq->lock is NOT held, but preemption is disabled */ 2243static inline void post_schedule(struct rq *rq) 2244{ 2245 if (rq->post_schedule) { 2246 unsigned long flags; 2247 2248 raw_spin_lock_irqsave(&rq->lock, flags); 2249 if (rq->curr->sched_class->post_schedule) 2250 rq->curr->sched_class->post_schedule(rq); 2251 raw_spin_unlock_irqrestore(&rq->lock, flags); 2252 2253 rq->post_schedule = 0; 2254 } 2255} 2256 2257#else 2258 2259static inline void post_schedule(struct rq *rq) 2260{ 2261} 2262 2263#endif 2264 2265/** 2266 * schedule_tail - first thing a freshly forked thread must call. 2267 * @prev: the thread we just switched away from. 2268 */ 2269asmlinkage __visible void schedule_tail(struct task_struct *prev) 2270 __releases(rq->lock) 2271{ 2272 struct rq *rq = this_rq(); 2273 2274 finish_task_switch(rq, prev); 2275 2276 /* 2277 * FIXME: do we need to worry about rq being invalidated by the 2278 * task_switch? 2279 */ 2280 post_schedule(rq); 2281 2282#ifdef __ARCH_WANT_UNLOCKED_CTXSW 2283 /* In this case, finish_task_switch does not reenable preemption */ 2284 preempt_enable(); 2285#endif 2286 if (current->set_child_tid) 2287 put_user(task_pid_vnr(current), current->set_child_tid); 2288} 2289 2290/* 2291 * context_switch - switch to the new MM and the new 2292 * thread's register state. 2293 */ 2294static inline void 2295context_switch(struct rq *rq, struct task_struct *prev, 2296 struct task_struct *next) 2297{ 2298 struct mm_struct *mm, *oldmm; 2299 2300 prepare_task_switch(rq, prev, next); 2301 2302 mm = next->mm; 2303 oldmm = prev->active_mm; 2304 /* 2305 * For paravirt, this is coupled with an exit in switch_to to 2306 * combine the page table reload and the switch backend into 2307 * one hypercall. 2308 */ 2309 arch_start_context_switch(prev); 2310 2311 if (!mm) { 2312 next->active_mm = oldmm; 2313 atomic_inc(&oldmm->mm_count); 2314 enter_lazy_tlb(oldmm, next); 2315 } else 2316 switch_mm(oldmm, mm, next); 2317 2318 if (!prev->mm) { 2319 prev->active_mm = NULL; 2320 rq->prev_mm = oldmm; 2321 } 2322 /* 2323 * Since the runqueue lock will be released by the next 2324 * task (which is an invalid locking op but in the case 2325 * of the scheduler it's an obvious special-case), so we 2326 * do an early lockdep release here: 2327 */ 2328#ifndef __ARCH_WANT_UNLOCKED_CTXSW 2329 spin_release(&rq->lock.dep_map, 1, _THIS_IP_); 2330#endif 2331 2332 context_tracking_task_switch(prev, next); 2333 /* Here we just switch the register state and the stack. */ 2334 switch_to(prev, next, prev); 2335 2336 barrier(); 2337 /* 2338 * this_rq must be evaluated again because prev may have moved 2339 * CPUs since it called schedule(), thus the 'rq' on its stack 2340 * frame will be invalid. 2341 */ 2342 finish_task_switch(this_rq(), prev); 2343} 2344 2345/* 2346 * nr_running and nr_context_switches: 2347 * 2348 * externally visible scheduler statistics: current number of runnable 2349 * threads, total number of context switches performed since bootup. 2350 */ 2351unsigned long nr_running(void) 2352{ 2353 unsigned long i, sum = 0; 2354 2355 for_each_online_cpu(i) 2356 sum += cpu_rq(i)->nr_running; 2357 2358 return sum; 2359} 2360 2361unsigned long long nr_context_switches(void) 2362{ 2363 int i; 2364 unsigned long long sum = 0; 2365 2366 for_each_possible_cpu(i) 2367 sum += cpu_rq(i)->nr_switches; 2368 2369 return sum; 2370} 2371 2372unsigned long nr_iowait(void) 2373{ 2374 unsigned long i, sum = 0; 2375 2376 for_each_possible_cpu(i) 2377 sum += atomic_read(&cpu_rq(i)->nr_iowait); 2378 2379 return sum; 2380} 2381 2382unsigned long nr_iowait_cpu(int cpu) 2383{ 2384 struct rq *this = cpu_rq(cpu); 2385 return atomic_read(&this->nr_iowait); 2386} 2387 2388#ifdef CONFIG_SMP 2389 2390/* 2391 * sched_exec - execve() is a valuable balancing opportunity, because at 2392 * this point the task has the smallest effective memory and cache footprint. 2393 */ 2394void sched_exec(void) 2395{ 2396 struct task_struct *p = current; 2397 unsigned long flags; 2398 int dest_cpu; 2399 2400 raw_spin_lock_irqsave(&p->pi_lock, flags); 2401 dest_cpu = p->sched_class->select_task_rq(p, task_cpu(p), SD_BALANCE_EXEC, 0); 2402 if (dest_cpu == smp_processor_id()) 2403 goto unlock; 2404 2405 if (likely(cpu_active(dest_cpu))) { 2406 struct migration_arg arg = { p, dest_cpu }; 2407 2408 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 2409 stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg); 2410 return; 2411 } 2412unlock: 2413 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 2414} 2415 2416#endif 2417 2418DEFINE_PER_CPU(struct kernel_stat, kstat); 2419DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat); 2420 2421EXPORT_PER_CPU_SYMBOL(kstat); 2422EXPORT_PER_CPU_SYMBOL(kernel_cpustat); 2423 2424/* 2425 * Return any ns on the sched_clock that have not yet been accounted in 2426 * @p in case that task is currently running. 2427 * 2428 * Called with task_rq_lock() held on @rq. 2429 */ 2430static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq) 2431{ 2432 u64 ns = 0; 2433 2434 if (task_current(rq, p)) { 2435 update_rq_clock(rq); 2436 ns = rq_clock_task(rq) - p->se.exec_start; 2437 if ((s64)ns < 0) 2438 ns = 0; 2439 } 2440 2441 return ns; 2442} 2443 2444unsigned long long task_delta_exec(struct task_struct *p) 2445{ 2446 unsigned long flags; 2447 struct rq *rq; 2448 u64 ns = 0; 2449 2450 rq = task_rq_lock(p, &flags); 2451 ns = do_task_delta_exec(p, rq); 2452 task_rq_unlock(rq, p, &flags); 2453 2454 return ns; 2455} 2456 2457/* 2458 * Return accounted runtime for the task. 2459 * In case the task is currently running, return the runtime plus current's 2460 * pending runtime that have not been accounted yet. 2461 */ 2462unsigned long long task_sched_runtime(struct task_struct *p) 2463{ 2464 unsigned long flags; 2465 struct rq *rq; 2466 u64 ns = 0; 2467 2468#if defined(CONFIG_64BIT) && defined(CONFIG_SMP) 2469 /* 2470 * 64-bit doesn't need locks to atomically read a 64bit value. 2471 * So we have a optimization chance when the task's delta_exec is 0. 2472 * Reading ->on_cpu is racy, but this is ok. 2473 * 2474 * If we race with it leaving cpu, we'll take a lock. So we're correct. 2475 * If we race with it entering cpu, unaccounted time is 0. This is 2476 * indistinguishable from the read occurring a few cycles earlier. 2477 */ 2478 if (!p->on_cpu) 2479 return p->se.sum_exec_runtime; 2480#endif 2481 2482 rq = task_rq_lock(p, &flags); 2483 ns = p->se.sum_exec_runtime + do_task_delta_exec(p, rq); 2484 task_rq_unlock(rq, p, &flags); 2485 2486 return ns; 2487} 2488 2489/* 2490 * This function gets called by the timer code, with HZ frequency. 2491 * We call it with interrupts disabled. 2492 */ 2493void scheduler_tick(void) 2494{ 2495 int cpu = smp_processor_id(); 2496 struct rq *rq = cpu_rq(cpu); 2497 struct task_struct *curr = rq->curr; 2498 2499 sched_clock_tick(); 2500 2501 raw_spin_lock(&rq->lock); 2502 update_rq_clock(rq); 2503 curr->sched_class->task_tick(rq, curr, 0); 2504 update_cpu_load_active(rq); 2505 raw_spin_unlock(&rq->lock); 2506 2507 perf_event_task_tick(); 2508 2509#ifdef CONFIG_SMP 2510 rq->idle_balance = idle_cpu(cpu); 2511 trigger_load_balance(rq); 2512#endif 2513 rq_last_tick_reset(rq); 2514} 2515 2516#ifdef CONFIG_NO_HZ_FULL 2517/** 2518 * scheduler_tick_max_deferment 2519 * 2520 * Keep at least one tick per second when a single 2521 * active task is running because the scheduler doesn't 2522 * yet completely support full dynticks environment. 2523 * 2524 * This makes sure that uptime, CFS vruntime, load 2525 * balancing, etc... continue to move forward, even 2526 * with a very low granularity. 2527 * 2528 * Return: Maximum deferment in nanoseconds. 2529 */ 2530u64 scheduler_tick_max_deferment(void) 2531{ 2532 struct rq *rq = this_rq(); 2533 unsigned long next, now = ACCESS_ONCE(jiffies); 2534 2535 next = rq->last_sched_tick + HZ; 2536 2537 if (time_before_eq(next, now)) 2538 return 0; 2539 2540 return jiffies_to_nsecs(next - now); 2541} 2542#endif 2543 2544notrace unsigned long get_parent_ip(unsigned long addr) 2545{ 2546 if (in_lock_functions(addr)) { 2547 addr = CALLER_ADDR2; 2548 if (in_lock_functions(addr)) 2549 addr = CALLER_ADDR3; 2550 } 2551 return addr; 2552} 2553 2554#if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \ 2555 defined(CONFIG_PREEMPT_TRACER)) 2556 2557void preempt_count_add(int val) 2558{ 2559#ifdef CONFIG_DEBUG_PREEMPT 2560 /* 2561 * Underflow? 2562 */ 2563 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) 2564 return; 2565#endif 2566 __preempt_count_add(val); 2567#ifdef CONFIG_DEBUG_PREEMPT 2568 /* 2569 * Spinlock count overflowing soon? 2570 */ 2571 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= 2572 PREEMPT_MASK - 10); 2573#endif 2574 if (preempt_count() == val) { 2575 unsigned long ip = get_parent_ip(CALLER_ADDR1); 2576#ifdef CONFIG_DEBUG_PREEMPT 2577 current->preempt_disable_ip = ip; 2578#endif 2579 trace_preempt_off(CALLER_ADDR0, ip); 2580 } 2581} 2582EXPORT_SYMBOL(preempt_count_add); 2583NOKPROBE_SYMBOL(preempt_count_add); 2584 2585void preempt_count_sub(int val) 2586{ 2587#ifdef CONFIG_DEBUG_PREEMPT 2588 /* 2589 * Underflow? 2590 */ 2591 if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) 2592 return; 2593 /* 2594 * Is the spinlock portion underflowing? 2595 */ 2596 if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && 2597 !(preempt_count() & PREEMPT_MASK))) 2598 return; 2599#endif 2600 2601 if (preempt_count() == val) 2602 trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); 2603 __preempt_count_sub(val); 2604} 2605EXPORT_SYMBOL(preempt_count_sub); 2606NOKPROBE_SYMBOL(preempt_count_sub); 2607 2608#endif 2609 2610/* 2611 * Print scheduling while atomic bug: 2612 */ 2613static noinline void __schedule_bug(struct task_struct *prev) 2614{ 2615 if (oops_in_progress) 2616 return; 2617 2618 printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n", 2619 prev->comm, prev->pid, preempt_count()); 2620 2621 debug_show_held_locks(prev); 2622 print_modules(); 2623 if (irqs_disabled()) 2624 print_irqtrace_events(prev); 2625#ifdef CONFIG_DEBUG_PREEMPT 2626 if (in_atomic_preempt_off()) { 2627 pr_err("Preemption disabled at:"); 2628 print_ip_sym(current->preempt_disable_ip); 2629 pr_cont("\n"); 2630 } 2631#endif 2632 dump_stack(); 2633 add_taint(TAINT_WARN, LOCKDEP_STILL_OK); 2634} 2635 2636/* 2637 * Various schedule()-time debugging checks and statistics: 2638 */ 2639static inline void schedule_debug(struct task_struct *prev) 2640{ 2641 /* 2642 * Test if we are atomic. Since do_exit() needs to call into 2643 * schedule() atomically, we ignore that path. Otherwise whine 2644 * if we are scheduling when we should not. 2645 */ 2646 if (unlikely(in_atomic_preempt_off() && prev->state != TASK_DEAD)) 2647 __schedule_bug(prev); 2648 rcu_sleep_check(); 2649 2650 profile_hit(SCHED_PROFILING, __builtin_return_address(0)); 2651 2652 schedstat_inc(this_rq(), sched_count); 2653} 2654 2655/* 2656 * Pick up the highest-prio task: 2657 */ 2658static inline struct task_struct * 2659pick_next_task(struct rq *rq, struct task_struct *prev) 2660{ 2661 const struct sched_class *class = &fair_sched_class; 2662 struct task_struct *p; 2663 2664 /* 2665 * Optimization: we know that if all tasks are in 2666 * the fair class we can call that function directly: 2667 */ 2668 if (likely(prev->sched_class == class && 2669 rq->nr_running == rq->cfs.h_nr_running)) { 2670 p = fair_sched_class.pick_next_task(rq, prev); 2671 if (unlikely(p == RETRY_TASK)) 2672 goto again; 2673 2674 /* assumes fair_sched_class->next == idle_sched_class */ 2675 if (unlikely(!p)) 2676 p = idle_sched_class.pick_next_task(rq, prev); 2677 2678 return p; 2679 } 2680 2681again: 2682 for_each_class(class) { 2683 p = class->pick_next_task(rq, prev); 2684 if (p) { 2685 if (unlikely(p == RETRY_TASK)) 2686 goto again; 2687 return p; 2688 } 2689 } 2690 2691 BUG(); /* the idle class will always have a runnable task */ 2692} 2693 2694/* 2695 * __schedule() is the main scheduler function. 2696 * 2697 * The main means of driving the scheduler and thus entering this function are: 2698 * 2699 * 1. Explicit blocking: mutex, semaphore, waitqueue, etc. 2700 * 2701 * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return 2702 * paths. For example, see arch/x86/entry_64.S. 2703 * 2704 * To drive preemption between tasks, the scheduler sets the flag in timer 2705 * interrupt handler scheduler_tick(). 2706 * 2707 * 3. Wakeups don't really cause entry into schedule(). They add a 2708 * task to the run-queue and that's it. 2709 * 2710 * Now, if the new task added to the run-queue preempts the current 2711 * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets 2712 * called on the nearest possible occasion: 2713 * 2714 * - If the kernel is preemptible (CONFIG_PREEMPT=y): 2715 * 2716 * - in syscall or exception context, at the next outmost 2717 * preempt_enable(). (this might be as soon as the wake_up()'s 2718 * spin_unlock()!) 2719 * 2720 * - in IRQ context, return from interrupt-handler to 2721 * preemptible context 2722 * 2723 * - If the kernel is not preemptible (CONFIG_PREEMPT is not set) 2724 * then at the next: 2725 * 2726 * - cond_resched() call 2727 * - explicit schedule() call 2728 * - return from syscall or exception to user-space 2729 * - return from interrupt-handler to user-space 2730 */ 2731static void __sched __schedule(void) 2732{ 2733 struct task_struct *prev, *next; 2734 unsigned long *switch_count; 2735 struct rq *rq; 2736 int cpu; 2737 2738need_resched: 2739 preempt_disable(); 2740 cpu = smp_processor_id(); 2741 rq = cpu_rq(cpu); 2742 rcu_note_context_switch(cpu); 2743 prev = rq->curr; 2744 2745 schedule_debug(prev); 2746 2747 if (sched_feat(HRTICK)) 2748 hrtick_clear(rq); 2749 2750 /* 2751 * Make sure that signal_pending_state()->signal_pending() below 2752 * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE) 2753 * done by the caller to avoid the race with signal_wake_up(). 2754 */ 2755 smp_mb__before_spinlock(); 2756 raw_spin_lock_irq(&rq->lock); 2757 2758 switch_count = &prev->nivcsw; 2759 if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { 2760 if (unlikely(signal_pending_state(prev->state, prev))) { 2761 prev->state = TASK_RUNNING; 2762 } else { 2763 deactivate_task(rq, prev, DEQUEUE_SLEEP); 2764 prev->on_rq = 0; 2765 2766 /* 2767 * If a worker went to sleep, notify and ask workqueue 2768 * whether it wants to wake up a task to maintain 2769 * concurrency. 2770 */ 2771 if (prev->flags & PF_WQ_WORKER) { 2772 struct task_struct *to_wakeup; 2773 2774 to_wakeup = wq_worker_sleeping(prev, cpu); 2775 if (to_wakeup) 2776 try_to_wake_up_local(to_wakeup); 2777 } 2778 } 2779 switch_count = &prev->nvcsw; 2780 } 2781 2782 if (prev->on_rq || rq->skip_clock_update < 0) 2783 update_rq_clock(rq); 2784 2785 next = pick_next_task(rq, prev); 2786 clear_tsk_need_resched(prev); 2787 clear_preempt_need_resched(); 2788 rq->skip_clock_update = 0; 2789 2790 if (likely(prev != next)) { 2791 rq->nr_switches++; 2792 rq->curr = next; 2793 ++*switch_count; 2794 2795 context_switch(rq, prev, next); /* unlocks the rq */ 2796 /* 2797 * The context switch have flipped the stack from under us 2798 * and restored the local variables which were saved when 2799 * this task called schedule() in the past. prev == current 2800 * is still correct, but it can be moved to another cpu/rq. 2801 */ 2802 cpu = smp_processor_id(); 2803 rq = cpu_rq(cpu); 2804 } else 2805 raw_spin_unlock_irq(&rq->lock); 2806 2807 post_schedule(rq); 2808 2809 sched_preempt_enable_no_resched(); 2810 if (need_resched()) 2811 goto need_resched; 2812} 2813 2814static inline void sched_submit_work(struct task_struct *tsk) 2815{ 2816 if (!tsk->state || tsk_is_pi_blocked(tsk)) 2817 return; 2818 /* 2819 * If we are going to sleep and we have plugged IO queued, 2820 * make sure to submit it to avoid deadlocks. 2821 */ 2822 if (blk_needs_flush_plug(tsk)) 2823 blk_schedule_flush_plug(tsk); 2824} 2825 2826asmlinkage __visible void __sched schedule(void) 2827{ 2828 struct task_struct *tsk = current; 2829 2830 sched_submit_work(tsk); 2831 __schedule(); 2832} 2833EXPORT_SYMBOL(schedule); 2834 2835#ifdef CONFIG_CONTEXT_TRACKING 2836asmlinkage __visible void __sched schedule_user(void) 2837{ 2838 /* 2839 * If we come here after a random call to set_need_resched(), 2840 * or we have been woken up remotely but the IPI has not yet arrived, 2841 * we haven't yet exited the RCU idle mode. Do it here manually until 2842 * we find a better solution. 2843 */ 2844 user_exit(); 2845 schedule(); 2846 user_enter(); 2847} 2848#endif 2849 2850/** 2851 * schedule_preempt_disabled - called with preemption disabled 2852 * 2853 * Returns with preemption disabled. Note: preempt_count must be 1 2854 */ 2855void __sched schedule_preempt_disabled(void) 2856{ 2857 sched_preempt_enable_no_resched(); 2858 schedule(); 2859 preempt_disable(); 2860} 2861 2862#ifdef CONFIG_PREEMPT 2863/* 2864 * this is the entry point to schedule() from in-kernel preemption 2865 * off of preempt_enable. Kernel preemptions off return from interrupt 2866 * occur there and call schedule directly. 2867 */ 2868asmlinkage __visible void __sched notrace preempt_schedule(void) 2869{ 2870 /* 2871 * If there is a non-zero preempt_count or interrupts are disabled, 2872 * we do not want to preempt the current task. Just return.. 2873 */ 2874 if (likely(!preemptible())) 2875 return; 2876 2877 do { 2878 __preempt_count_add(PREEMPT_ACTIVE); 2879 __schedule(); 2880 __preempt_count_sub(PREEMPT_ACTIVE); 2881 2882 /* 2883 * Check again in case we missed a preemption opportunity 2884 * between schedule and now. 2885 */ 2886 barrier(); 2887 } while (need_resched()); 2888} 2889NOKPROBE_SYMBOL(preempt_schedule); 2890EXPORT_SYMBOL(preempt_schedule); 2891#endif /* CONFIG_PREEMPT */ 2892 2893/* 2894 * this is the entry point to schedule() from kernel preemption 2895 * off of irq context. 2896 * Note, that this is called and return with irqs disabled. This will 2897 * protect us against recursive calling from irq. 2898 */ 2899asmlinkage __visible void __sched preempt_schedule_irq(void) 2900{ 2901 enum ctx_state prev_state; 2902 2903 /* Catch callers which need to be fixed */ 2904 BUG_ON(preempt_count() || !irqs_disabled()); 2905 2906 prev_state = exception_enter(); 2907 2908 do { 2909 __preempt_count_add(PREEMPT_ACTIVE); 2910 local_irq_enable(); 2911 __schedule(); 2912 local_irq_disable(); 2913 __preempt_count_sub(PREEMPT_ACTIVE); 2914 2915 /* 2916 * Check again in case we missed a preemption opportunity 2917 * between schedule and now. 2918 */ 2919 barrier(); 2920 } while (need_resched()); 2921 2922 exception_exit(prev_state); 2923} 2924 2925int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags, 2926 void *key) 2927{ 2928 return try_to_wake_up(curr->private, mode, wake_flags); 2929} 2930EXPORT_SYMBOL(default_wake_function); 2931 2932#ifdef CONFIG_RT_MUTEXES 2933 2934/* 2935 * rt_mutex_setprio - set the current priority of a task 2936 * @p: task 2937 * @prio: prio value (kernel-internal form) 2938 * 2939 * This function changes the 'effective' priority of a task. It does 2940 * not touch ->normal_prio like __setscheduler(). 2941 * 2942 * Used by the rt_mutex code to implement priority inheritance 2943 * logic. Call site only calls if the priority of the task changed. 2944 */ 2945void rt_mutex_setprio(struct task_struct *p, int prio) 2946{ 2947 int oldprio, on_rq, running, enqueue_flag = 0; 2948 struct rq *rq; 2949 const struct sched_class *prev_class; 2950 2951 BUG_ON(prio > MAX_PRIO); 2952 2953 rq = __task_rq_lock(p); 2954 2955 /* 2956 * Idle task boosting is a nono in general. There is one 2957 * exception, when PREEMPT_RT and NOHZ is active: 2958 * 2959 * The idle task calls get_next_timer_interrupt() and holds 2960 * the timer wheel base->lock on the CPU and another CPU wants 2961 * to access the timer (probably to cancel it). We can safely 2962 * ignore the boosting request, as the idle CPU runs this code 2963 * with interrupts disabled and will complete the lock 2964 * protected section without being interrupted. So there is no 2965 * real need to boost. 2966 */ 2967 if (unlikely(p == rq->idle)) { 2968 WARN_ON(p != rq->curr); 2969 WARN_ON(p->pi_blocked_on); 2970 goto out_unlock; 2971 } 2972 2973 trace_sched_pi_setprio(p, prio); 2974 p->pi_top_task = rt_mutex_get_top_task(p); 2975 oldprio = p->prio; 2976 prev_class = p->sched_class; 2977 on_rq = p->on_rq; 2978 running = task_current(rq, p); 2979 if (on_rq) 2980 dequeue_task(rq, p, 0); 2981 if (running) 2982 p->sched_class->put_prev_task(rq, p); 2983 2984 /* 2985 * Boosting condition are: 2986 * 1. -rt task is running and holds mutex A 2987 * --> -dl task blocks on mutex A 2988 * 2989 * 2. -dl task is running and holds mutex A 2990 * --> -dl task blocks on mutex A and could preempt the 2991 * running task 2992 */ 2993 if (dl_prio(prio)) { 2994 if (!dl_prio(p->normal_prio) || (p->pi_top_task && 2995 dl_entity_preempt(&p->pi_top_task->dl, &p->dl))) { 2996 p->dl.dl_boosted = 1; 2997 p->dl.dl_throttled = 0; 2998 enqueue_flag = ENQUEUE_REPLENISH; 2999 } else 3000 p->dl.dl_boosted = 0; 3001 p->sched_class = &dl_sched_class; 3002 } else if (rt_prio(prio)) { 3003 if (dl_prio(oldprio)) 3004 p->dl.dl_boosted = 0; 3005 if (oldprio < prio) 3006 enqueue_flag = ENQUEUE_HEAD; 3007 p->sched_class = &rt_sched_class; 3008 } else { 3009 if (dl_prio(oldprio)) 3010 p->dl.dl_boosted = 0; 3011 p->sched_class = &fair_sched_class; 3012 } 3013 3014 p->prio = prio; 3015 3016 if (running) 3017 p->sched_class->set_curr_task(rq); 3018 if (on_rq) 3019 enqueue_task(rq, p, enqueue_flag); 3020 3021 check_class_changed(rq, p, prev_class, oldprio); 3022out_unlock: 3023 __task_rq_unlock(rq); 3024} 3025#endif 3026 3027void set_user_nice(struct task_struct *p, long nice) 3028{ 3029 int old_prio, delta, on_rq; 3030 unsigned long flags; 3031 struct rq *rq; 3032 3033 if (task_nice(p) == nice || nice < MIN_NICE || nice > MAX_NICE) 3034 return; 3035 /* 3036 * We have to be careful, if called from sys_setpriority(), 3037 * the task might be in the middle of scheduling on another CPU. 3038 */ 3039 rq = task_rq_lock(p, &flags); 3040 /* 3041 * The RT priorities are set via sched_setscheduler(), but we still 3042 * allow the 'normal' nice value to be set - but as expected 3043 * it wont have any effect on scheduling until the task is 3044 * SCHED_DEADLINE, SCHED_FIFO or SCHED_RR: 3045 */ 3046 if (task_has_dl_policy(p) || task_has_rt_policy(p)) { 3047 p->static_prio = NICE_TO_PRIO(nice); 3048 goto out_unlock; 3049 } 3050 on_rq = p->on_rq; 3051 if (on_rq) 3052 dequeue_task(rq, p, 0); 3053 3054 p->static_prio = NICE_TO_PRIO(nice); 3055 set_load_weight(p); 3056 old_prio = p->prio; 3057 p->prio = effective_prio(p); 3058 delta = p->prio - old_prio; 3059 3060 if (on_rq) { 3061 enqueue_task(rq, p, 0); 3062 /* 3063 * If the task increased its priority or is running and 3064 * lowered its priority, then reschedule its CPU: 3065 */ 3066 if (delta < 0 || (delta > 0 && task_running(rq, p))) 3067 resched_task(rq->curr); 3068 } 3069out_unlock: 3070 task_rq_unlock(rq, p, &flags); 3071} 3072EXPORT_SYMBOL(set_user_nice); 3073 3074/* 3075 * can_nice - check if a task can reduce its nice value 3076 * @p: task 3077 * @nice: nice value 3078 */ 3079int can_nice(const struct task_struct *p, const int nice) 3080{ 3081 /* convert nice value [19,-20] to rlimit style value [1,40] */ 3082 int nice_rlim = nice_to_rlimit(nice); 3083 3084 return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) || 3085 capable(CAP_SYS_NICE)); 3086} 3087 3088#ifdef __ARCH_WANT_SYS_NICE 3089 3090/* 3091 * sys_nice - change the priority of the current process. 3092 * @increment: priority increment 3093 * 3094 * sys_setpriority is a more generic, but much slower function that 3095 * does similar things. 3096 */ 3097SYSCALL_DEFINE1(nice, int, increment) 3098{ 3099 long nice, retval; 3100 3101 /* 3102 * Setpriority might change our priority at the same moment. 3103 * We don't have to worry. Conceptually one call occurs first 3104 * and we have a single winner. 3105 */ 3106 increment = clamp(increment, -NICE_WIDTH, NICE_WIDTH); 3107 nice = task_nice(current) + increment; 3108 3109 nice = clamp_val(nice, MIN_NICE, MAX_NICE); 3110 if (increment < 0 && !can_nice(current, nice)) 3111 return -EPERM; 3112 3113 retval = security_task_setnice(current, nice); 3114 if (retval) 3115 return retval; 3116 3117 set_user_nice(current, nice); 3118 return 0; 3119} 3120 3121#endif 3122 3123/** 3124 * task_prio - return the priority value of a given task. 3125 * @p: the task in question. 3126 * 3127 * Return: The priority value as seen by users in /proc. 3128 * RT tasks are offset by -200. Normal tasks are centered 3129 * around 0, value goes from -16 to +15. 3130 */ 3131int task_prio(const struct task_struct *p) 3132{ 3133 return p->prio - MAX_RT_PRIO; 3134} 3135 3136/** 3137 * idle_cpu - is a given cpu idle currently? 3138 * @cpu: the processor in question. 3139 * 3140 * Return: 1 if the CPU is currently idle. 0 otherwise. 3141 */ 3142int idle_cpu(int cpu) 3143{ 3144 struct rq *rq = cpu_rq(cpu); 3145 3146 if (rq->curr != rq->idle) 3147 return 0; 3148 3149 if (rq->nr_running) 3150 return 0; 3151 3152#ifdef CONFIG_SMP 3153 if (!llist_empty(&rq->wake_list)) 3154 return 0; 3155#endif 3156 3157 return 1; 3158} 3159 3160/** 3161 * idle_task - return the idle task for a given cpu. 3162 * @cpu: the processor in question. 3163 * 3164 * Return: The idle task for the cpu @cpu. 3165 */ 3166struct task_struct *idle_task(int cpu) 3167{ 3168 return cpu_rq(cpu)->idle; 3169} 3170 3171/** 3172 * find_process_by_pid - find a process with a matching PID value. 3173 * @pid: the pid in question. 3174 * 3175 * The task of @pid, if found. %NULL otherwise. 3176 */ 3177static struct task_struct *find_process_by_pid(pid_t pid) 3178{ 3179 return pid ? find_task_by_vpid(pid) : current; 3180} 3181 3182/* 3183 * This function initializes the sched_dl_entity of a newly becoming 3184 * SCHED_DEADLINE task. 3185 * 3186 * Only the static values are considered here, the actual runtime and the 3187 * absolute deadline will be properly calculated when the task is enqueued 3188 * for the first time with its new policy. 3189 */ 3190static void 3191__setparam_dl(struct task_struct *p, const struct sched_attr *attr) 3192{ 3193 struct sched_dl_entity *dl_se = &p->dl; 3194 3195 init_dl_task_timer(dl_se); 3196 dl_se->dl_runtime = attr->sched_runtime; 3197 dl_se->dl_deadline = attr->sched_deadline; 3198 dl_se->dl_period = attr->sched_period ?: dl_se->dl_deadline; 3199 dl_se->flags = attr->sched_flags; 3200 dl_se->dl_bw = to_ratio(dl_se->dl_period, dl_se->dl_runtime); 3201 dl_se->dl_throttled = 0; 3202 dl_se->dl_new = 1; 3203 dl_se->dl_yielded = 0; 3204} 3205 3206static void __setscheduler_params(struct task_struct *p, 3207 const struct sched_attr *attr) 3208{ 3209 int policy = attr->sched_policy; 3210 3211 if (policy == -1) /* setparam */ 3212 policy = p->policy; 3213 3214 p->policy = policy; 3215 3216 if (dl_policy(policy)) 3217 __setparam_dl(p, attr); 3218 else if (fair_policy(policy)) 3219 p->static_prio = NICE_TO_PRIO(attr->sched_nice); 3220 3221 /* 3222 * __sched_setscheduler() ensures attr->sched_priority == 0 when 3223 * !rt_policy. Always setting this ensures that things like 3224 * getparam()/getattr() don't report silly values for !rt tasks. 3225 */ 3226 p->rt_priority = attr->sched_priority; 3227 p->normal_prio = normal_prio(p); 3228 set_load_weight(p); 3229} 3230 3231/* Actually do priority change: must hold pi & rq lock. */ 3232static void __setscheduler(struct rq *rq, struct task_struct *p, 3233 const struct sched_attr *attr) 3234{ 3235 __setscheduler_params(p, attr); 3236 3237 /* 3238 * If we get here, there was no pi waiters boosting the 3239 * task. It is safe to use the normal prio. 3240 */ 3241 p->prio = normal_prio(p); 3242 3243 if (dl_prio(p->prio)) 3244 p->sched_class = &dl_sched_class; 3245 else if (rt_prio(p->prio)) 3246 p->sched_class = &rt_sched_class; 3247 else 3248 p->sched_class = &fair_sched_class; 3249} 3250 3251static void 3252__getparam_dl(struct task_struct *p, struct sched_attr *attr) 3253{ 3254 struct sched_dl_entity *dl_se = &p->dl; 3255 3256 attr->sched_priority = p->rt_priority; 3257 attr->sched_runtime = dl_se->dl_runtime; 3258 attr->sched_deadline = dl_se->dl_deadline; 3259 attr->sched_period = dl_se->dl_period; 3260 attr->sched_flags = dl_se->flags; 3261} 3262 3263/* 3264 * This function validates the new parameters of a -deadline task. 3265 * We ask for the deadline not being zero, and greater or equal 3266 * than the runtime, as well as the period of being zero or 3267 * greater than deadline. Furthermore, we have to be sure that 3268 * user parameters are above the internal resolution of 1us (we 3269 * check sched_runtime only since it is always the smaller one) and 3270 * below 2^63 ns (we have to check both sched_deadline and 3271 * sched_period, as the latter can be zero). 3272 */ 3273static bool 3274__checkparam_dl(const struct sched_attr *attr) 3275{ 3276 /* deadline != 0 */ 3277 if (attr->sched_deadline == 0) 3278 return false; 3279 3280 /* 3281 * Since we truncate DL_SCALE bits, make sure we're at least 3282 * that big. 3283 */ 3284 if (attr->sched_runtime < (1ULL << DL_SCALE)) 3285 return false; 3286 3287 /* 3288 * Since we use the MSB for wrap-around and sign issues, make 3289 * sure it's not set (mind that period can be equal to zero). 3290 */ 3291 if (attr->sched_deadline & (1ULL << 63) || 3292 attr->sched_period & (1ULL << 63)) 3293 return false; 3294 3295 /* runtime <= deadline <= period (if period != 0) */ 3296 if ((attr->sched_period != 0 && 3297 attr->sched_period < attr->sched_deadline) || 3298 attr->sched_deadline < attr->sched_runtime) 3299 return false; 3300 3301 return true; 3302} 3303 3304/* 3305 * check the target process has a UID that matches the current process's 3306 */ 3307static bool check_same_owner(struct task_struct *p) 3308{ 3309 const struct cred *cred = current_cred(), *pcred; 3310 bool match; 3311 3312 rcu_read_lock(); 3313 pcred = __task_cred(p); 3314 match = (uid_eq(cred->euid, pcred->euid) || 3315 uid_eq(cred->euid, pcred->uid)); 3316 rcu_read_unlock(); 3317 return match; 3318} 3319 3320static int __sched_setscheduler(struct task_struct *p, 3321 const struct sched_attr *attr, 3322 bool user) 3323{ 3324 int newprio = dl_policy(attr->sched_policy) ? MAX_DL_PRIO - 1 : 3325 MAX_RT_PRIO - 1 - attr->sched_priority; 3326 int retval, oldprio, oldpolicy = -1, on_rq, running; 3327 int policy = attr->sched_policy; 3328 unsigned long flags; 3329 const struct sched_class *prev_class; 3330 struct rq *rq; 3331 int reset_on_fork; 3332 3333 /* may grab non-irq protected spin_locks */ 3334 BUG_ON(in_interrupt()); 3335recheck: 3336 /* double check policy once rq lock held */ 3337 if (policy < 0) { 3338 reset_on_fork = p->sched_reset_on_fork; 3339 policy = oldpolicy = p->policy; 3340 } else { 3341 reset_on_fork = !!(attr->sched_flags & SCHED_FLAG_RESET_ON_FORK); 3342 3343 if (policy != SCHED_DEADLINE && 3344 policy != SCHED_FIFO && policy != SCHED_RR && 3345 policy != SCHED_NORMAL && policy != SCHED_BATCH && 3346 policy != SCHED_IDLE) 3347 return -EINVAL; 3348 } 3349 3350 if (attr->sched_flags & ~(SCHED_FLAG_RESET_ON_FORK)) 3351 return -EINVAL; 3352 3353 /* 3354 * Valid priorities for SCHED_FIFO and SCHED_RR are 3355 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL, 3356 * SCHED_BATCH and SCHED_IDLE is 0. 3357 */ 3358 if ((p->mm && attr->sched_priority > MAX_USER_RT_PRIO-1) || 3359 (!p->mm && attr->sched_priority > MAX_RT_PRIO-1)) 3360 return -EINVAL; 3361 if ((dl_policy(policy) && !__checkparam_dl(attr)) || 3362 (rt_policy(policy) != (attr->sched_priority != 0))) 3363 return -EINVAL; 3364 3365 /* 3366 * Allow unprivileged RT tasks to decrease priority: 3367 */ 3368 if (user && !capable(CAP_SYS_NICE)) { 3369 if (fair_policy(policy)) { 3370 if (attr->sched_nice < task_nice(p) && 3371 !can_nice(p, attr->sched_nice)) 3372 return -EPERM; 3373 } 3374 3375 if (rt_policy(policy)) { 3376 unsigned long rlim_rtprio = 3377 task_rlimit(p, RLIMIT_RTPRIO); 3378 3379 /* can't set/change the rt policy */ 3380 if (policy != p->policy && !rlim_rtprio) 3381 return -EPERM; 3382 3383 /* can't increase priority */ 3384 if (attr->sched_priority > p->rt_priority && 3385 attr->sched_priority > rlim_rtprio) 3386 return -EPERM; 3387 } 3388 3389 /* 3390 * Can't set/change SCHED_DEADLINE policy at all for now 3391 * (safest behavior); in the future we would like to allow 3392 * unprivileged DL tasks to increase their relative deadline 3393 * or reduce their runtime (both ways reducing utilization) 3394 */ 3395 if (dl_policy(policy)) 3396 return -EPERM; 3397 3398 /* 3399 * Treat SCHED_IDLE as nice 20. Only allow a switch to 3400 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it. 3401 */ 3402 if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) { 3403 if (!can_nice(p, task_nice(p))) 3404 return -EPERM; 3405 } 3406 3407 /* can't change other user's priorities */ 3408 if (!check_same_owner(p)) 3409 return -EPERM; 3410 3411 /* Normal users shall not reset the sched_reset_on_fork flag */ 3412 if (p->sched_reset_on_fork && !reset_on_fork) 3413 return -EPERM; 3414 } 3415 3416 if (user) { 3417 retval = security_task_setscheduler(p); 3418 if (retval) 3419 return retval; 3420 } 3421 3422 /* 3423 * make sure no PI-waiters arrive (or leave) while we are 3424 * changing the priority of the task: 3425 * 3426 * To be able to change p->policy safely, the appropriate 3427 * runqueue lock must be held. 3428 */ 3429 rq = task_rq_lock(p, &flags); 3430 3431 /* 3432 * Changing the policy of the stop threads its a very bad idea 3433 */ 3434 if (p == rq->stop) { 3435 task_rq_unlock(rq, p, &flags); 3436 return -EINVAL; 3437 } 3438 3439 /* 3440 * If not changing anything there's no need to proceed further, 3441 * but store a possible modification of reset_on_fork. 3442 */ 3443 if (unlikely(policy == p->policy)) { 3444 if (fair_policy(policy) && attr->sched_nice != task_nice(p)) 3445 goto change; 3446 if (rt_policy(policy) && attr->sched_priority != p->rt_priority) 3447 goto change; 3448 if (dl_policy(policy)) 3449 goto change; 3450 3451 p->sched_reset_on_fork = reset_on_fork; 3452 task_rq_unlock(rq, p, &flags); 3453 return 0; 3454 } 3455change: 3456 3457 if (user) { 3458#ifdef CONFIG_RT_GROUP_SCHED 3459 /* 3460 * Do not allow realtime tasks into groups that have no runtime 3461 * assigned. 3462 */ 3463 if (rt_bandwidth_enabled() && rt_policy(policy) && 3464 task_group(p)->rt_bandwidth.rt_runtime == 0 && 3465 !task_group_is_autogroup(task_group(p))) { 3466 task_rq_unlock(rq, p, &flags); 3467 return -EPERM; 3468 } 3469#endif 3470#ifdef CONFIG_SMP 3471 if (dl_bandwidth_enabled() && dl_policy(policy)) { 3472 cpumask_t *span = rq->rd->span; 3473 3474 /* 3475 * Don't allow tasks with an affinity mask smaller than 3476 * the entire root_domain to become SCHED_DEADLINE. We 3477 * will also fail if there's no bandwidth available. 3478 */ 3479 if (!cpumask_subset(span, &p->cpus_allowed) || 3480 rq->rd->dl_bw.bw == 0) { 3481 task_rq_unlock(rq, p, &flags); 3482 return -EPERM; 3483 } 3484 } 3485#endif 3486 } 3487 3488 /* recheck policy now with rq lock held */ 3489 if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { 3490 policy = oldpolicy = -1; 3491 task_rq_unlock(rq, p, &flags); 3492 goto recheck; 3493 } 3494 3495 /* 3496 * If setscheduling to SCHED_DEADLINE (or changing the parameters 3497 * of a SCHED_DEADLINE task) we need to check if enough bandwidth 3498 * is available. 3499 */ 3500 if ((dl_policy(policy) || dl_task(p)) && dl_overflow(p, policy, attr)) { 3501 task_rq_unlock(rq, p, &flags); 3502 return -EBUSY; 3503 } 3504 3505 p->sched_reset_on_fork = reset_on_fork; 3506 oldprio = p->prio; 3507 3508 /* 3509 * Special case for priority boosted tasks. 3510 * 3511 * If the new priority is lower or equal (user space view) 3512 * than the current (boosted) priority, we just store the new 3513 * normal parameters and do not touch the scheduler class and 3514 * the runqueue. This will be done when the task deboost 3515 * itself. 3516 */ 3517 if (rt_mutex_check_prio(p, newprio)) { 3518 __setscheduler_params(p, attr); 3519 task_rq_unlock(rq, p, &flags); 3520 return 0; 3521 } 3522 3523 on_rq = p->on_rq; 3524 running = task_current(rq, p); 3525 if (on_rq) 3526 dequeue_task(rq, p, 0); 3527 if (running) 3528 p->sched_class->put_prev_task(rq, p); 3529 3530 prev_class = p->sched_class; 3531 __setscheduler(rq, p, attr); 3532 3533 if (running) 3534 p->sched_class->set_curr_task(rq); 3535 if (on_rq) { 3536 /* 3537 * We enqueue to tail when the priority of a task is 3538 * increased (user space view). 3539 */ 3540 enqueue_task(rq, p, oldprio <= p->prio ? ENQUEUE_HEAD : 0); 3541 } 3542 3543 check_class_changed(rq, p, prev_class, oldprio); 3544 task_rq_unlock(rq, p, &flags); 3545 3546 rt_mutex_adjust_pi(p); 3547 3548 return 0; 3549} 3550 3551static int _sched_setscheduler(struct task_struct *p, int policy, 3552 const struct sched_param *param, bool check) 3553{ 3554 struct sched_attr attr = { 3555 .sched_policy = policy, 3556 .sched_priority = param->sched_priority, 3557 .sched_nice = PRIO_TO_NICE(p->static_prio), 3558 }; 3559 3560 /* 3561 * Fixup the legacy SCHED_RESET_ON_FORK hack 3562 */ 3563 if (policy & SCHED_RESET_ON_FORK) { 3564 attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK; 3565 policy &= ~SCHED_RESET_ON_FORK; 3566 attr.sched_policy = policy; 3567 } 3568 3569 return __sched_setscheduler(p, &attr, check); 3570} 3571/** 3572 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. 3573 * @p: the task in question. 3574 * @policy: new policy. 3575 * @param: structure containing the new RT priority. 3576 * 3577 * Return: 0 on success. An error code otherwise. 3578 * 3579 * NOTE that the task may be already dead. 3580 */ 3581int sched_setscheduler(struct task_struct *p, int policy, 3582 const struct sched_param *param) 3583{ 3584 return _sched_setscheduler(p, policy, param, true); 3585} 3586EXPORT_SYMBOL_GPL(sched_setscheduler); 3587 3588int sched_setattr(struct task_struct *p, const struct sched_attr *attr) 3589{ 3590 return __sched_setscheduler(p, attr, true); 3591} 3592EXPORT_SYMBOL_GPL(sched_setattr); 3593 3594/** 3595 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace. 3596 * @p: the task in question. 3597 * @policy: new policy. 3598 * @param: structure containing the new RT priority. 3599 * 3600 * Just like sched_setscheduler, only don't bother checking if the 3601 * current context has permission. For example, this is needed in 3602 * stop_machine(): we create temporary high priority worker threads, 3603 * but our caller might not have that capability. 3604 * 3605 * Return: 0 on success. An error code otherwise. 3606 */ 3607int sched_setscheduler_nocheck(struct task_struct *p, int policy, 3608 const struct sched_param *param) 3609{ 3610 return _sched_setscheduler(p, policy, param, false); 3611} 3612 3613static int 3614do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) 3615{ 3616 struct sched_param lparam; 3617 struct task_struct *p; 3618 int retval; 3619 3620 if (!param || pid < 0) 3621 return -EINVAL; 3622 if (copy_from_user(&lparam, param, sizeof(struct sched_param))) 3623 return -EFAULT; 3624 3625 rcu_read_lock(); 3626 retval = -ESRCH; 3627 p = find_process_by_pid(pid); 3628 if (p != NULL) 3629 retval = sched_setscheduler(p, policy, &lparam); 3630 rcu_read_unlock(); 3631 3632 return retval; 3633} 3634 3635/* 3636 * Mimics kernel/events/core.c perf_copy_attr(). 3637 */ 3638static int sched_copy_attr(struct sched_attr __user *uattr, 3639 struct sched_attr *attr) 3640{ 3641 u32 size; 3642 int ret; 3643 3644 if (!access_ok(VERIFY_WRITE, uattr, SCHED_ATTR_SIZE_VER0)) 3645 return -EFAULT; 3646 3647 /* 3648 * zero the full structure, so that a short copy will be nice. 3649 */ 3650 memset(attr, 0, sizeof(*attr)); 3651 3652 ret = get_user(size, &uattr->size); 3653 if (ret) 3654 return ret; 3655 3656 if (size > PAGE_SIZE) /* silly large */ 3657 goto err_size; 3658 3659 if (!size) /* abi compat */ 3660 size = SCHED_ATTR_SIZE_VER0; 3661 3662 if (size < SCHED_ATTR_SIZE_VER0) 3663 goto err_size; 3664 3665 /* 3666 * If we're handed a bigger struct than we know of, 3667 * ensure all the unknown bits are 0 - i.e. new 3668 * user-space does not rely on any kernel feature 3669 * extensions we dont know about yet. 3670 */ 3671 if (size > sizeof(*attr)) { 3672 unsigned char __user *addr; 3673 unsigned char __user *end; 3674 unsigned char val; 3675 3676 addr = (void __user *)uattr + sizeof(*attr); 3677 end = (void __user *)uattr + size; 3678 3679 for (; addr < end; addr++) { 3680 ret = get_user(val, addr); 3681 if (ret) 3682 return ret; 3683 if (val) 3684 goto err_size; 3685 } 3686 size = sizeof(*attr); 3687 } 3688 3689 ret = copy_from_user(attr, uattr, size); 3690 if (ret) 3691 return -EFAULT; 3692 3693 /* 3694 * XXX: do we want to be lenient like existing syscalls; or do we want 3695 * to be strict and return an error on out-of-bounds values? 3696 */ 3697 attr->sched_nice = clamp(attr->sched_nice, MIN_NICE, MAX_NICE); 3698 3699 return 0; 3700 3701err_size: 3702 put_user(sizeof(*attr), &uattr->size); 3703 return -E2BIG; 3704} 3705 3706/** 3707 * sys_sched_setscheduler - set/change the scheduler policy and RT priority 3708 * @pid: the pid in question. 3709 * @policy: new policy. 3710 * @param: structure containing the new RT priority. 3711 * 3712 * Return: 0 on success. An error code otherwise. 3713 */ 3714SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy, 3715 struct sched_param __user *, param) 3716{ 3717 /* negative values for policy are not valid */ 3718 if (policy < 0) 3719 return -EINVAL; 3720 3721 return do_sched_setscheduler(pid, policy, param); 3722} 3723 3724/** 3725 * sys_sched_setparam - set/change the RT priority of a thread 3726 * @pid: the pid in question. 3727 * @param: structure containing the new RT priority. 3728 * 3729 * Return: 0 on success. An error code otherwise. 3730 */ 3731SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param) 3732{ 3733 return do_sched_setscheduler(pid, -1, param); 3734} 3735 3736/** 3737 * sys_sched_setattr - same as above, but with extended sched_attr 3738 * @pid: the pid in question. 3739 * @uattr: structure containing the extended parameters. 3740 * @flags: for future extension. 3741 */ 3742SYSCALL_DEFINE3(sched_setattr, pid_t, pid, struct sched_attr __user *, uattr, 3743 unsigned int, flags) 3744{ 3745 struct sched_attr attr; 3746 struct task_struct *p; 3747 int retval; 3748 3749 if (!uattr || pid < 0 || flags) 3750 return -EINVAL; 3751 3752 retval = sched_copy_attr(uattr, &attr); 3753 if (retval) 3754 return retval; 3755 3756 if ((int)attr.sched_policy < 0) 3757 return -EINVAL; 3758 3759 rcu_read_lock(); 3760 retval = -ESRCH; 3761 p = find_process_by_pid(pid); 3762 if (p != NULL) 3763 retval = sched_setattr(p, &attr); 3764 rcu_read_unlock(); 3765 3766 return retval; 3767} 3768 3769/** 3770 * sys_sched_getscheduler - get the policy (scheduling class) of a thread 3771 * @pid: the pid in question. 3772 * 3773 * Return: On success, the policy of the thread. Otherwise, a negative error 3774 * code. 3775 */ 3776SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid) 3777{ 3778 struct task_struct *p; 3779 int retval; 3780 3781 if (pid < 0) 3782 return -EINVAL; 3783 3784 retval = -ESRCH; 3785 rcu_read_lock(); 3786 p = find_process_by_pid(pid); 3787 if (p) { 3788 retval = security_task_getscheduler(p); 3789 if (!retval) 3790 retval = p->policy 3791 | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0); 3792 } 3793 rcu_read_unlock(); 3794 return retval; 3795} 3796 3797/** 3798 * sys_sched_getparam - get the RT priority of a thread 3799 * @pid: the pid in question. 3800 * @param: structure containing the RT priority. 3801 * 3802 * Return: On success, 0 and the RT priority is in @param. Otherwise, an error 3803 * code. 3804 */ 3805SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param) 3806{ 3807 struct sched_param lp = { .sched_priority = 0 }; 3808 struct task_struct *p; 3809 int retval; 3810 3811 if (!param || pid < 0) 3812 return -EINVAL; 3813 3814 rcu_read_lock(); 3815 p = find_process_by_pid(pid); 3816 retval = -ESRCH; 3817 if (!p) 3818 goto out_unlock; 3819 3820 retval = security_task_getscheduler(p); 3821 if (retval) 3822 goto out_unlock; 3823 3824 if (task_has_rt_policy(p)) 3825 lp.sched_priority = p->rt_priority; 3826 rcu_read_unlock(); 3827 3828 /* 3829 * This one might sleep, we cannot do it with a spinlock held ... 3830 */ 3831 retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; 3832 3833 return retval; 3834 3835out_unlock: 3836 rcu_read_unlock(); 3837 return retval; 3838} 3839 3840static int sched_read_attr(struct sched_attr __user *uattr, 3841 struct sched_attr *attr, 3842 unsigned int usize) 3843{ 3844 int ret; 3845 3846 if (!access_ok(VERIFY_WRITE, uattr, usize)) 3847 return -EFAULT; 3848 3849 /* 3850 * If we're handed a smaller struct than we know of, 3851 * ensure all the unknown bits are 0 - i.e. old 3852 * user-space does not get uncomplete information. 3853 */ 3854 if (usize < sizeof(*attr)) { 3855 unsigned char *addr; 3856 unsigned char *end; 3857 3858 addr = (void *)attr + usize; 3859 end = (void *)attr + sizeof(*attr); 3860 3861 for (; addr < end; addr++) { 3862 if (*addr) 3863 return -EFBIG; 3864 } 3865 3866 attr->size = usize; 3867 } 3868 3869 ret = copy_to_user(uattr, attr, attr->size); 3870 if (ret) 3871 return -EFAULT; 3872 3873 return 0; 3874} 3875 3876/** 3877 * sys_sched_getattr - similar to sched_getparam, but with sched_attr 3878 * @pid: the pid in question. 3879 * @uattr: structure containing the extended parameters. 3880 * @size: sizeof(attr) for fwd/bwd comp. 3881 * @flags: for future extension. 3882 */ 3883SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr, 3884 unsigned int, size, unsigned int, flags) 3885{ 3886 struct sched_attr attr = { 3887 .size = sizeof(struct sched_attr), 3888 }; 3889 struct task_struct *p; 3890 int retval; 3891 3892 if (!uattr || pid < 0 || size > PAGE_SIZE || 3893 size < SCHED_ATTR_SIZE_VER0 || flags) 3894 return -EINVAL; 3895 3896 rcu_read_lock(); 3897 p = find_process_by_pid(pid); 3898 retval = -ESRCH; 3899 if (!p) 3900 goto out_unlock; 3901 3902 retval = security_task_getscheduler(p); 3903 if (retval) 3904 goto out_unlock; 3905 3906 attr.sched_policy = p->policy; 3907 if (p->sched_reset_on_fork) 3908 attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK; 3909 if (task_has_dl_policy(p)) 3910 __getparam_dl(p, &attr); 3911 else if (task_has_rt_policy(p)) 3912 attr.sched_priority = p->rt_priority; 3913 else 3914 attr.sched_nice = task_nice(p); 3915 3916 rcu_read_unlock(); 3917 3918 retval = sched_read_attr(uattr, &attr, size); 3919 return retval; 3920 3921out_unlock: 3922 rcu_read_unlock(); 3923 return retval; 3924} 3925 3926long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) 3927{ 3928 cpumask_var_t cpus_allowed, new_mask; 3929 struct task_struct *p; 3930 int retval; 3931 3932 rcu_read_lock(); 3933 3934 p = find_process_by_pid(pid); 3935 if (!p) { 3936 rcu_read_unlock(); 3937 return -ESRCH; 3938 } 3939 3940 /* Prevent p going away */ 3941 get_task_struct(p); 3942 rcu_read_unlock(); 3943 3944 if (p->flags & PF_NO_SETAFFINITY) { 3945 retval = -EINVAL; 3946 goto out_put_task; 3947 } 3948 if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) { 3949 retval = -ENOMEM; 3950 goto out_put_task; 3951 } 3952 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) { 3953 retval = -ENOMEM; 3954 goto out_free_cpus_allowed; 3955 } 3956 retval = -EPERM; 3957 if (!check_same_owner(p)) { 3958 rcu_read_lock(); 3959 if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) { 3960 rcu_read_unlock(); 3961 goto out_unlock; 3962 } 3963 rcu_read_unlock(); 3964 } 3965 3966 retval = security_task_setscheduler(p); 3967 if (retval) 3968 goto out_unlock; 3969 3970 3971 cpuset_cpus_allowed(p, cpus_allowed); 3972 cpumask_and(new_mask, in_mask, cpus_allowed); 3973 3974 /* 3975 * Since bandwidth control happens on root_domain basis, 3976 * if admission test is enabled, we only admit -deadline 3977 * tasks allowed to run on all the CPUs in the task's 3978 * root_domain. 3979 */ 3980#ifdef CONFIG_SMP 3981 if (task_has_dl_policy(p)) { 3982 const struct cpumask *span = task_rq(p)->rd->span; 3983 3984 if (dl_bandwidth_enabled() && !cpumask_subset(span, new_mask)) { 3985 retval = -EBUSY; 3986 goto out_unlock; 3987 } 3988 } 3989#endif 3990again: 3991 retval = set_cpus_allowed_ptr(p, new_mask); 3992 3993 if (!retval) { 3994 cpuset_cpus_allowed(p, cpus_allowed); 3995 if (!cpumask_subset(new_mask, cpus_allowed)) { 3996 /* 3997 * We must have raced with a concurrent cpuset 3998 * update. Just reset the cpus_allowed to the 3999 * cpuset's cpus_allowed 4000 */ 4001 cpumask_copy(new_mask, cpus_allowed); 4002 goto again; 4003 } 4004 } 4005out_unlock: 4006 free_cpumask_var(new_mask); 4007out_free_cpus_allowed: 4008 free_cpumask_var(cpus_allowed); 4009out_put_task: 4010 put_task_struct(p); 4011 return retval; 4012} 4013 4014static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, 4015 struct cpumask *new_mask) 4016{ 4017 if (len < cpumask_size()) 4018 cpumask_clear(new_mask); 4019 else if (len > cpumask_size()) 4020 len = cpumask_size(); 4021 4022 return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; 4023} 4024 4025/** 4026 * sys_sched_setaffinity - set the cpu affinity of a process 4027 * @pid: pid of the process 4028 * @len: length in bytes of the bitmask pointed to by user_mask_ptr 4029 * @user_mask_ptr: user-space pointer to the new cpu mask 4030 * 4031 * Return: 0 on success. An error code otherwise. 4032 */ 4033SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len, 4034 unsigned long __user *, user_mask_ptr) 4035{ 4036 cpumask_var_t new_mask; 4037 int retval; 4038 4039 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) 4040 return -ENOMEM; 4041 4042 retval = get_user_cpu_mask(user_mask_ptr, len, new_mask); 4043 if (retval == 0) 4044 retval = sched_setaffinity(pid, new_mask); 4045 free_cpumask_var(new_mask); 4046 return retval; 4047} 4048 4049long sched_getaffinity(pid_t pid, struct cpumask *mask) 4050{ 4051 struct task_struct *p; 4052 unsigned long flags; 4053 int retval; 4054 4055 rcu_read_lock(); 4056 4057 retval = -ESRCH; 4058 p = find_process_by_pid(pid); 4059 if (!p) 4060 goto out_unlock; 4061 4062 retval = security_task_getscheduler(p); 4063 if (retval) 4064 goto out_unlock; 4065 4066 raw_spin_lock_irqsave(&p->pi_lock, flags); 4067 cpumask_and(mask, &p->cpus_allowed, cpu_active_mask); 4068 raw_spin_unlock_irqrestore(&p->pi_lock, flags); 4069 4070out_unlock: 4071 rcu_read_unlock(); 4072 4073 return retval; 4074} 4075 4076/** 4077 * sys_sched_getaffinity - get the cpu affinity of a process 4078 * @pid: pid of the process 4079 * @len: length in bytes of the bitmask pointed to by user_mask_ptr 4080 * @user_mask_ptr: user-space pointer to hold the current cpu mask 4081 * 4082 * Return: 0 on success. An error code otherwise. 4083 */ 4084SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len, 4085 unsigned long __user *, user_mask_ptr) 4086{ 4087 int ret; 4088 cpumask_var_t mask; 4089 4090 if ((len * BITS_PER_BYTE) < nr_cpu_ids) 4091 return -EINVAL; 4092 if (len & (sizeof(unsigned long)-1)) 4093 return -EINVAL; 4094 4095 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) 4096 return -ENOMEM; 4097 4098 ret = sched_getaffinity(pid, mask); 4099 if (ret == 0) { 4100 size_t retlen = min_t(size_t, len, cpumask_size()); 4101 4102 if (copy_to_user(user_mask_ptr, mask, retlen)) 4103 ret = -EFAULT; 4104 else 4105 ret = retlen; 4106 } 4107 free_cpumask_var(mask); 4108 4109 return ret; 4110} 4111 4112/** 4113 * sys_sched_yield - yield the current processor to other threads. 4114 * 4115 * This function yields the current CPU to other tasks. If there are no 4116 * other threads running on this CPU then this function will return. 4117 * 4118 * Return: 0. 4119 */ 4120SYSCALL_DEFINE0(sched_yield) 4121{ 4122 struct rq *rq = this_rq_lock(); 4123 4124 schedstat_inc(rq, yld_count); 4125 current->sched_class->yield_task(rq); 4126 4127 /* 4128 * Since we are going to call schedule() anyway, there's 4129 * no need to preempt or enable interrupts: 4130 */ 4131 __release(rq->lock); 4132 spin_release(&rq->lock.dep_map, 1, _THIS_IP_); 4133 do_raw_spin_unlock(&rq->lock); 4134 sched_preempt_enable_no_resched(); 4135 4136 schedule(); 4137 4138 return 0; 4139} 4140 4141static void __cond_resched(void) 4142{ 4143 __preempt_count_add(PREEMPT_ACTIVE); 4144 __schedule(); 4145 __preempt_count_sub(PREEMPT_ACTIVE); 4146} 4147 4148int __sched _cond_resched(void) 4149{ 4150 if (should_resched()) { 4151 __cond_resched(); 4152 return 1; 4153 } 4154 return 0; 4155} 4156EXPORT_SYMBOL(_cond_resched); 4157 4158/* 4159 * __cond_resched_lock() - if a reschedule is pending, drop the given lock, 4160 * call schedule, and on return reacquire the lock. 4161 * 4162 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level 4163 * operations here to prevent schedule() from being called twice (once via 4164 * spin_unlock(), once by hand). 4165 */ 4166int __cond_resched_lock(spinlock_t *lock) 4167{ 4168 int resched = should_resched(); 4169 int ret = 0; 4170 4171 lockdep_assert_held(lock); 4172 4173 if (spin_needbreak(lock) || resched) { 4174 spin_unlock(lock); 4175 if (resched) 4176 __cond_resched(); 4177 else 4178 cpu_relax(); 4179 ret = 1; 4180 spin_lock(lock); 4181 } 4182 return ret; 4183} 4184EXPORT_SYMBOL(__cond_resched_lock); 4185 4186int __sched __cond_resched_softirq(void) 4187{ 4188 BUG_ON(!in_softirq()); 4189 4190 if (should_resched()) { 4191 local_bh_enable(); 4192 __cond_resched(); 4193 local_bh_disable(); 4194 return 1; 4195 } 4196 return 0; 4197} 4198EXPORT_SYMBOL(__cond_resched_softirq); 4199 4200/** 4201 * yield - yield the current processor to other threads. 4202 * 4203 * Do not ever use this function, there's a 99% chance you're doing it wrong. 4204 * 4205 * The scheduler is at all times free to pick the calling task as the most 4206 * eligible task to run, if removing the yield() call from your code breaks 4207 * it, its already broken. 4208 * 4209 * Typical broken usage is: 4210 * 4211 * while (!event) 4212 * yield(); 4213 * 4214 * where one assumes that yield() will let 'the other' process run that will 4215 * make event true. If the current task is a SCHED_FIFO task that will never 4216 * happen. Never use yield() as a progress guarantee!! 4217 * 4218 * If you want to use yield() to wait for something, use wait_event(). 4219 * If you want to use yield() to be 'nice' for others, use cond_resched(). 4220 * If you still want to use yield(), do not! 4221 */ 4222void __sched yield(void) 4223{ 4224 set_current_state(TASK_RUNNING); 4225 sys_sched_yield(); 4226} 4227EXPORT_SYMBOL(yield); 4228 4229/** 4230 * yield_to - yield the current processor to another thread in 4231 * your thread group, or accelerate that thread toward the 4232 * processor it's on. 4233 * @p: target task 4234 * @preempt: whether task preemption is allowed or not 4235 * 4236 * It's the caller's job to ensure that the target task struct 4237 * can't go away on us before we can do any checks. 4238 * 4239 * Return: 4240 * true (>0) if we indeed boosted the target task. 4241 * false (0) if we failed to boost the target. 4242 * -ESRCH if there's no task to yield to. 4243 */ 4244int __sched yield_to(struct task_struct *p, bool preempt) 4245{ 4246 struct task_struct *curr = current; 4247 struct rq *rq, *p_rq; 4248 unsigned long flags; 4249 int yielded = 0; 4250 4251 local_irq_save(flags); 4252 rq = this_rq(); 4253 4254again: 4255 p_rq = task_rq(p); 4256 /* 4257 * If we're the only runnable task on the rq and target rq also 4258 * has only one task, there's absolutely no point in yielding. 4259 */ 4260 if (rq->nr_running == 1 && p_rq->nr_running == 1) { 4261 yielded = -ESRCH; 4262 goto out_irq; 4263 } 4264 4265 double_rq_lock(rq, p_rq); 4266 if (task_rq(p) != p_rq) { 4267 double_rq_unlock(rq, p_rq); 4268 goto again; 4269 } 4270 4271 if (!curr->sched_class->yield_to_task) 4272 goto out_unlock; 4273 4274 if (curr->sched_class != p->sched_class) 4275 goto out_unlock; 4276 4277 if (task_running(p_rq, p) || p->state) 4278 goto out_unlock; 4279 4280 yielded = curr->sched_class->yield_to_task(rq, p, preempt); 4281 if (yielded) { 4282 schedstat_inc(rq, yld_count); 4283 /* 4284 * Make p's CPU reschedule; pick_next_entity takes care of 4285 * fairness. 4286 */ 4287 if (preempt && rq != p_rq) 4288 resched_task(p_rq->curr); 4289 } 4290 4291out_unlock: 4292 double_rq_unlock(rq, p_rq); 4293out_irq: 4294 local_irq_restore(flags); 4295 4296 if (yielded > 0) 4297 schedule(); 4298 4299 return yielded; 4300} 4301EXPORT_SYMBOL_GPL(yield_to); 4302 4303/* 4304 * This task is about to go to sleep on IO. Increment rq->nr_iowait so 4305 * that process accounting knows that this is a task in IO wait state. 4306 */ 4307void __sched io_schedule(void) 4308{ 4309 struct rq *rq = raw_rq(); 4310 4311 delayacct_blkio_start(); 4312 atomic_inc(&rq->nr_iowait); 4313 blk_flush_plug(current); 4314 current->in_iowait = 1; 4315 schedule(); 4316 current->in_iowait = 0; 4317 atomic_dec(&rq->nr_iowait); 4318 delayacct_blkio_end(); 4319} 4320EXPORT_SYMBOL(io_schedule); 4321 4322long __sched io_schedule_timeout(long timeout) 4323{ 4324 struct rq *rq = raw_rq(); 4325 long ret; 4326 4327 delayacct_blkio_start(); 4328 atomic_inc(&rq->nr_iowait); 4329 blk_flush_plug(current); 4330 current->in_iowait = 1; 4331 ret = schedule_timeout(timeout); 4332 current->in_iowait = 0; 4333 atomic_dec(&rq->nr_iowait); 4334 delayacct_blkio_end(); 4335 return ret; 4336} 4337 4338/** 4339 * sys_sched_get_priority_max - return maximum RT priority. 4340 * @policy: scheduling class. 4341 * 4342 * Return: On success, this syscall returns the maximum 4343 * rt_priority that can be used by a given scheduling class. 4344 * On failure, a negative error code is returned. 4345 */ 4346SYSCALL_DEFINE1(sched_get_priority_max, int, policy) 4347{ 4348 int ret = -EINVAL; 4349 4350 switch (policy) { 4351 case SCHED_FIFO: 4352 case SCHED_RR: 4353 ret = MAX_USER_RT_PRIO-1; 4354 break; 4355 case SCHED_DEADLINE: 4356 case SCHED_NORMAL: 4357 case SCHED_BATCH: 4358 case SCHED_IDLE: 4359 ret = 0; 4360 break; 4361 } 4362 return ret; 4363} 4364 4365/** 4366 * sys_sched_get_priority_min - return minimum RT priority. 4367 * @policy: scheduling class. 4368 * 4369 * Return: On success, this syscall returns the minimum 4370 * rt_priority that can be used by a given scheduling class. 4371 * On failure, a negative error code is returned. 4372 */ 4373SYSCALL_DEFINE1(sched_get_priority_min, int, policy) 4374{ 4375 int ret = -EINVAL; 4376 4377 switch (policy) { 4378 case SCHED_FIFO: 4379 case SCHED_RR: 4380 ret = 1; 4381 break; 4382 case SCHED_DEADLINE: 4383 case SCHED_NORMAL: 4384 case SCHED_BATCH: 4385 case SCHED_IDLE: 4386 ret = 0; 4387 } 4388 return ret; 4389} 4390 4391/** 4392 * sys_sched_rr_get_interval - return the default timeslice of a process. 4393 * @pid: pid of the process. 4394 * @interval: userspace pointer to the timeslice value. 4395 * 4396 * this syscall writes the default timeslice value of a given process 4397 * into the user-space timespec buffer. A value of '0' means infinity. 4398 * 4399 * Return: On success, 0 and the timeslice is in @interval. Otherwise, 4400 * an error code. 4401 */ 4402SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid, 4403 struct timespec __user *, interval) 4404{ 4405 struct task_struct *p; 4406 unsigned int time_slice; 4407 unsigned long flags; 4408 struct rq *rq; 4409 int retval; 4410 struct timespec t; 4411 4412 if (pid < 0) 4413 return -EINVAL; 4414 4415 retval = -ESRCH; 4416 rcu_read_lock(); 4417 p = find_process_by_pid(pid); 4418 if (!p) 4419 goto out_unlock; 4420 4421 retval = security_task_getscheduler(p); 4422 if (retval) 4423 goto out_unlock; 4424 4425 rq = task_rq_lock(p, &flags); 4426 time_slice = 0; 4427 if (p->sched_class->get_rr_interval) 4428 time_slice = p->sched_class->get_rr_interval(rq, p); 4429 task_rq_unlock(rq, p, &flags); 4430 4431 rcu_read_unlock(); 4432 jiffies_to_timespec(time_slice, &t); 4433 retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; 4434 return retval; 4435 4436out_unlock: 4437 rcu_read_unlock(); 4438 return retval; 4439} 4440 4441static const char stat_nam[] = TASK_STATE_TO_CHAR_STR; 4442 4443void sched_show_task(struct task_struct *p) 4444{ 4445 unsigned long free = 0; 4446 int ppid; 4447 unsigned state; 4448 4449 state = p->state ? __ffs(p->state) + 1 : 0; 4450 printk(KERN_INFO "%-15.15s %c", p->comm, 4451 state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); 4452#if BITS_PER_LONG == 32 4453 if (state == TASK_RUNNING) 4454 printk(KERN_CONT " running "); 4455 else 4456 printk(KERN_CONT " %08lx ", thread_saved_pc(p)); 4457#else 4458 if (state == TASK_RUNNING) 4459 printk(KERN_CONT " running task "); 4460 else 4461 printk(KERN_CONT " %016lx ", thread_saved_pc(p)); 4462#endif 4463#ifdef CONFIG_DEBUG_STACK_USAGE 4464 free = stack_not_used(p); 4465#endif 4466 rcu_read_lock(); 4467 ppid = task_pid_nr(rcu_dereference(p->real_parent)); 4468 rcu_read_unlock(); 4469 printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free, 4470 task_pid_nr(p), ppid, 4471 (unsigned long)task_thread_info(p)->flags); 4472 4473 print_worker_info(KERN_INFO, p); 4474 show_stack(p, NULL); 4475} 4476 4477void show_state_filter(unsigned long state_filter) 4478{ 4479 struct task_struct *g, *p; 4480 4481#if BITS_PER_LONG == 32 4482 printk(KERN_INFO 4483 " task PC stack pid father\n"); 4484#else 4485 printk(KERN_INFO 4486 " task PC stack pid father\n"); 4487#endif 4488 rcu_read_lock(); 4489 do_each_thread(g, p) { 4490 /* 4491 * reset the NMI-timeout, listing all files on a slow 4492 * console might take a lot of time: 4493 */ 4494 touch_nmi_watchdog(); 4495 if (!state_filter || (p->state & state_filter)) 4496 sched_show_task(p); 4497 } while_each_thread(g, p); 4498 4499 touch_all_softlockup_watchdogs(); 4500 4501#ifdef CONFIG_SCHED_DEBUG 4502 sysrq_sched_debug_show(); 4503#endif 4504 rcu_read_unlock(); 4505 /* 4506 * Only show locks if all tasks are dumped: 4507 */ 4508 if (!state_filter) 4509 debug_show_all_locks(); 4510} 4511 4512void init_idle_bootup_task(struct task_struct *idle) 4513{ 4514 idle->sched_class = &idle_sched_class; 4515} 4516 4517/** 4518 * init_idle - set up an idle thread for a given CPU 4519 * @idle: task in question 4520 * @cpu: cpu the idle task belongs to 4521 * 4522 * NOTE: this function does not set the idle thread's NEED_RESCHED 4523 * flag, to make booting more robust. 4524 */ 4525void init_idle(struct task_struct *idle, int cpu) 4526{ 4527 struct rq *rq = cpu_rq(cpu); 4528 unsigned long flags; 4529 4530 raw_spin_lock_irqsave(&rq->lock, flags); 4531 4532 __sched_fork(0, idle); 4533 idle->state = TASK_RUNNING; 4534 idle->se.exec_start = sched_clock(); 4535 4536 do_set_cpus_allowed(idle, cpumask_of(cpu)); 4537 /* 4538 * We're having a chicken and egg problem, even though we are 4539 * holding rq->lock, the cpu isn't yet set to this cpu so the 4540 * lockdep check in task_group() will fail. 4541 * 4542 * Similar case to sched_fork(). / Alternatively we could 4543 * use task_rq_lock() here and obtain the other rq->lock. 4544 * 4545 * Silence PROVE_RCU 4546 */ 4547 rcu_read_lock(); 4548 __set_task_cpu(idle, cpu); 4549 rcu_read_unlock(); 4550 4551 rq->curr = rq->idle = idle; 4552 idle->on_rq = 1; 4553#if defined(CONFIG_SMP) 4554 idle->on_cpu = 1; 4555#endif 4556 raw_spin_unlock_irqrestore(&rq->lock, flags); 4557 4558 /* Set the preempt count _outside_ the spinlocks! */ 4559 init_idle_preempt_count(idle, cpu); 4560 4561 /* 4562 * The idle tasks have their own, simple scheduling class: 4563 */ 4564 idle->sched_class = &idle_sched_class; 4565 ftrace_graph_init_idle_task(idle, cpu); 4566 vtime_init_idle(idle, cpu); 4567#if defined(CONFIG_SMP) 4568 sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu); 4569#endif 4570} 4571 4572#ifdef CONFIG_SMP 4573void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) 4574{ 4575 if (p->sched_class && p->sched_class->set_cpus_allowed) 4576 p->sched_class->set_cpus_allowed(p, new_mask); 4577 4578 cpumask_copy(&p->cpus_allowed, new_mask); 4579 p->nr_cpus_allowed = cpumask_weight(new_mask); 4580} 4581 4582/* 4583 * This is how migration works: 4584 * 4585 * 1) we invoke migration_cpu_stop() on the target CPU using 4586 * stop_one_cpu(). 4587 * 2) stopper starts to run (implicitly forcing the migrated thread 4588 * off the CPU) 4589 * 3) it checks whether the migrated task is still in the wrong runqueue. 4590 * 4) if it's in the wrong runqueue then the migration thread removes 4591 * it and puts it into the right queue. 4592 * 5) stopper completes and stop_one_cpu() returns and the migration 4593 * is done. 4594 */ 4595 4596/* 4597 * Change a given task's CPU affinity. Migrate the thread to a 4598 * proper CPU and schedule it away if the CPU it's executing on 4599 * is removed from the allowed bitmask. 4600 * 4601 * NOTE: the caller must have a valid reference to the task, the 4602 * task must not exit() & deallocate itself prematurely. The 4603 * call is not atomic; no spinlocks may be held. 4604 */ 4605int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) 4606{ 4607 unsigned long flags; 4608 struct rq *rq; 4609 unsigned int dest_cpu; 4610 int ret = 0; 4611 4612 rq = task_rq_lock(p, &flags); 4613 4614 if (cpumask_equal(&p->cpus_allowed, new_mask)) 4615 goto out; 4616 4617 if (!cpumask_intersects(new_mask, cpu_active_mask)) { 4618 ret = -EINVAL; 4619 goto out; 4620 } 4621 4622 do_set_cpus_allowed(p, new_mask); 4623 4624 /* Can the task run on the task's current CPU? If so, we're done */ 4625 if (cpumask_test_cpu(task_cpu(p), new_mask)) 4626 goto out; 4627 4628 dest_cpu = cpumask_any_and(cpu_active_mask, new_mask); 4629 if (p->on_rq) { 4630 struct migration_arg arg = { p, dest_cpu }; 4631 /* Need help from migration thread: drop lock and wait. */ 4632 task_rq_unlock(rq, p, &flags); 4633 stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg); 4634 tlb_migrate_finish(p->mm); 4635 return 0; 4636 } 4637out: 4638 task_rq_unlock(rq, p, &flags); 4639 4640 return ret; 4641} 4642EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr); 4643 4644/* 4645 * Move (not current) task off this cpu, onto dest cpu. We're doing 4646 * this because either it can't run here any more (set_cpus_allowed() 4647 * away from this CPU, or CPU going down), or because we're 4648 * attempting to rebalance this task on exec (sched_exec). 4649 * 4650 * So we race with normal scheduler movements, but that's OK, as long 4651 * as the task is no longer on this CPU. 4652 * 4653 * Returns non-zero if task was successfully migrated. 4654 */ 4655static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) 4656{ 4657 struct rq *rq_dest, *rq_src; 4658 int ret = 0; 4659 4660 if (unlikely(!cpu_active(dest_cpu))) 4661 return ret; 4662 4663 rq_src = cpu_rq(src_cpu); 4664 rq_dest = cpu_rq(dest_cpu); 4665 4666 raw_spin_lock(&p->pi_lock); 4667 double_rq_lock(rq_src, rq_dest); 4668 /* Already moved. */ 4669 if (task_cpu(p) != src_cpu) 4670 goto done; 4671 /* Affinity changed (again). */ 4672 if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) 4673 goto fail; 4674 4675 /* 4676 * If we're not on a rq, the next wake-up will ensure we're 4677 * placed properly. 4678 */ 4679 if (p->on_rq) { 4680 dequeue_task(rq_src, p, 0); 4681 set_task_cpu(p, dest_cpu); 4682 enqueue_task(rq_dest, p, 0); 4683 check_preempt_curr(rq_dest, p, 0); 4684 } 4685done: 4686 ret = 1; 4687fail: 4688 double_rq_unlock(rq_src, rq_dest); 4689 raw_spin_unlock(&p->pi_lock); 4690 return ret; 4691} 4692 4693#ifdef CONFIG_NUMA_BALANCING 4694/* Migrate current task p to target_cpu */ 4695int migrate_task_to(struct task_struct *p, int target_cpu) 4696{ 4697 struct migration_arg arg = { p, target_cpu }; 4698 int curr_cpu = task_cpu(p); 4699 4700 if (curr_cpu == target_cpu) 4701 return 0; 4702 4703 if (!cpumask_test_cpu(target_cpu, tsk_cpus_allowed(p))) 4704 return -EINVAL; 4705 4706 /* TODO: This is not properly updating schedstats */ 4707 4708 trace_sched_move_numa(p, curr_cpu, target_cpu); 4709 return stop_one_cpu(curr_cpu, migration_cpu_stop, &arg); 4710} 4711 4712/* 4713 * Requeue a task on a given node and accurately track the number of NUMA 4714 * tasks on the runqueues 4715 */ 4716void sched_setnuma(struct task_struct *p, int nid) 4717{ 4718 struct rq *rq; 4719 unsigned long flags; 4720 bool on_rq, running; 4721 4722 rq = task_rq_lock(p, &flags); 4723 on_rq = p->on_rq; 4724 running = task_current(rq, p); 4725 4726 if (on_rq) 4727 dequeue_task(rq, p, 0); 4728 if (running) 4729 p->sched_class->put_prev_task(rq, p); 4730 4731 p->numa_preferred_nid = nid; 4732 4733 if (running) 4734 p->sched_class->set_curr_task(rq); 4735 if (on_rq) 4736 enqueue_task(rq, p, 0); 4737 task_rq_unlock(rq, p, &flags); 4738} 4739#endif 4740 4741/* 4742 * migration_cpu_stop - this will be executed by a highprio stopper thread 4743 * and performs thread migration by bumping thread off CPU then 4744 * 'pushing' onto another runqueue. 4745 */ 4746static int migration_cpu_stop(void *data) 4747{ 4748 struct migration_arg *arg = data; 4749 4750 /* 4751 * The original target cpu might have gone down and we might 4752 * be on another cpu but it doesn't matter. 4753 */ 4754 local_irq_disable(); 4755 __migrate_task(arg->task, raw_smp_processor_id(), arg->dest_cpu); 4756 local_irq_enable(); 4757 return 0; 4758} 4759 4760#ifdef CONFIG_HOTPLUG_CPU 4761 4762/* 4763 * Ensures that the idle task is using init_mm right before its cpu goes 4764 * offline. 4765 */ 4766void idle_task_exit(void) 4767{ 4768 struct mm_struct *mm = current->active_mm; 4769 4770 BUG_ON(cpu_online(smp_processor_id())); 4771 4772 if (mm != &init_mm) { 4773 switch_mm(mm, &init_mm, current); 4774 finish_arch_post_lock_switch(); 4775 } 4776 mmdrop(mm); 4777} 4778 4779/* 4780 * Since this CPU is going 'away' for a while, fold any nr_active delta 4781 * we might have. Assumes we're called after migrate_tasks() so that the 4782 * nr_active count is stable. 4783 * 4784 * Also see the comment "Global load-average calculations". 4785 */ 4786static void calc_load_migrate(struct rq *rq) 4787{ 4788 long delta = calc_load_fold_active(rq); 4789 if (delta) 4790 atomic_long_add(delta, &calc_load_tasks); 4791} 4792 4793static void put_prev_task_fake(struct rq *rq, struct task_struct *prev) 4794{ 4795} 4796 4797static const struct sched_class fake_sched_class = { 4798 .put_prev_task = put_prev_task_fake, 4799}; 4800 4801static struct task_struct fake_task = { 4802 /* 4803 * Avoid pull_{rt,dl}_task() 4804 */ 4805 .prio = MAX_PRIO + 1, 4806 .sched_class = &fake_sched_class, 4807}; 4808 4809/* 4810 * Migrate all tasks from the rq, sleeping tasks will be migrated by 4811 * try_to_wake_up()->select_task_rq(). 4812 * 4813 * Called with rq->lock held even though we'er in stop_machine() and 4814 * there's no concurrency possible, we hold the required locks anyway 4815 * because of lock validation efforts. 4816 */ 4817static void migrate_tasks(unsigned int dead_cpu) 4818{ 4819 struct rq *rq = cpu_rq(dead_cpu); 4820 struct task_struct *next, *stop = rq->stop; 4821 int dest_cpu; 4822 4823 /* 4824 * Fudge the rq selection such that the below task selection loop 4825 * doesn't get stuck on the currently eligible stop task. 4826 * 4827 * We're currently inside stop_machine() and the rq is either stuck 4828 * in the stop_machine_cpu_stop() loop, or we're executing this code, 4829 * either way we should never end up calling schedule() until we're 4830 * done here. 4831 */ 4832 rq->stop = NULL; 4833 4834 /* 4835 * put_prev_task() and pick_next_task() sched 4836 * class method both need to have an up-to-date 4837 * value of rq->clock[_task] 4838 */ 4839 update_rq_clock(rq); 4840 4841 for ( ; ; ) { 4842 /* 4843 * There's this thread running, bail when that's the only 4844 * remaining thread. 4845 */ 4846 if (rq->nr_running == 1) 4847 break; 4848 4849 next = pick_next_task(rq, &fake_task); 4850 BUG_ON(!next); 4851 next->sched_class->put_prev_task(rq, next); 4852 4853 /* Find suitable destination for @next, with force if needed. */ 4854 dest_cpu = select_fallback_rq(dead_cpu, next); 4855 raw_spin_unlock(&rq->lock); 4856 4857 __migrate_task(next, dead_cpu, dest_cpu); 4858 4859 raw_spin_lock(&rq->lock); 4860 } 4861 4862 rq->stop = stop; 4863} 4864 4865#endif /* CONFIG_HOTPLUG_CPU */ 4866 4867#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL) 4868 4869static struct ctl_table sd_ctl_dir[] = { 4870 { 4871 .procname = "sched_domain", 4872 .mode = 0555, 4873 }, 4874 {} 4875}; 4876 4877static struct ctl_table sd_ctl_root[] = { 4878 { 4879 .procname = "kernel", 4880 .mode = 0555, 4881 .child = sd_ctl_dir, 4882 }, 4883 {} 4884}; 4885 4886static struct ctl_table *sd_alloc_ctl_entry(int n) 4887{ 4888 struct ctl_table *entry = 4889 kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL); 4890 4891 return entry; 4892} 4893 4894static void sd_free_ctl_entry(struct ctl_table **tablep) 4895{ 4896 struct ctl_table *entry; 4897 4898 /* 4899 * In the intermediate directories, both the child directory and 4900 * procname are dynamically allocated and could fail but the mode 4901 * will always be set. In the lowest directory the names are 4902 * static strings and all have proc handlers. 4903 */ 4904 for (entry = *tablep; entry->mode; entry++) { 4905 if (entry->child) 4906 sd_free_ctl_entry(&entry->child); 4907 if (entry->proc_handler == NULL) 4908 kfree(entry->procname); 4909 } 4910 4911 kfree(*tablep); 4912 *tablep = NULL; 4913} 4914 4915static int min_load_idx = 0; 4916static int max_load_idx = CPU_LOAD_IDX_MAX-1; 4917 4918static void 4919set_table_entry(struct ctl_table *entry, 4920 const char *procname, void *data, int maxlen, 4921 umode_t mode, proc_handler *proc_handler, 4922 bool load_idx) 4923{ 4924 entry->procname = procname; 4925 entry->data = data; 4926 entry->maxlen = maxlen; 4927 entry->mode = mode; 4928 entry->proc_handler = proc_handler; 4929 4930 if (load_idx) { 4931 entry->extra1 = &min_load_idx; 4932 entry->extra2 = &max_load_idx; 4933 } 4934} 4935 4936static struct ctl_table * 4937sd_alloc_ctl_domain_table(struct sched_domain *sd) 4938{ 4939 struct ctl_table *table = sd_alloc_ctl_entry(14); 4940 4941 if (table == NULL) 4942 return NULL; 4943 4944 set_table_entry(&table[0], "min_interval", &sd->min_interval, 4945 sizeof(long), 0644, proc_doulongvec_minmax, false); 4946 set_table_entry(&table[1], "max_interval", &sd->max_interval, 4947 sizeof(long), 0644, proc_doulongvec_minmax, false); 4948 set_table_entry(&table[2], "busy_idx", &sd->busy_idx, 4949 sizeof(int), 0644, proc_dointvec_minmax, true); 4950 set_table_entry(&table[3], "idle_idx", &sd->idle_idx, 4951 sizeof(int), 0644, proc_dointvec_minmax, true); 4952 set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx, 4953 sizeof(int), 0644, proc_dointvec_minmax, true); 4954 set_table_entry(&table[5], "wake_idx", &sd->wake_idx, 4955 sizeof(int), 0644, proc_dointvec_minmax, true); 4956 set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx, 4957 sizeof(int), 0644, proc_dointvec_minmax, true); 4958 set_table_entry(&table[7], "busy_factor", &sd->busy_factor, 4959 sizeof(int), 0644, proc_dointvec_minmax, false); 4960 set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct, 4961 sizeof(int), 0644, proc_dointvec_minmax, false); 4962 set_table_entry(&table[9], "cache_nice_tries", 4963 &sd->cache_nice_tries, 4964 sizeof(int), 0644, proc_dointvec_minmax, false); 4965 set_table_entry(&table[10], "flags", &sd->flags, 4966 sizeof(int), 0644, proc_dointvec_minmax, false); 4967 set_table_entry(&table[11], "max_newidle_lb_cost", 4968 &sd->max_newidle_lb_cost, 4969 sizeof(long), 0644, proc_doulongvec_minmax, false); 4970 set_table_entry(&table[12], "name", sd->name, 4971 CORENAME_MAX_SIZE, 0444, proc_dostring, false); 4972 /* &table[13] is terminator */ 4973 4974 return table; 4975} 4976 4977static struct ctl_table *sd_alloc_ctl_cpu_table(int cpu) 4978{ 4979 struct ctl_table *entry, *table; 4980 struct sched_domain *sd; 4981 int domain_num = 0, i; 4982 char buf[32]; 4983 4984 for_each_domain(cpu, sd) 4985 domain_num++; 4986 entry = table = sd_alloc_ctl_entry(domain_num + 1); 4987 if (table == NULL) 4988 return NULL; 4989 4990 i = 0; 4991 for_each_domain(cpu, sd) { 4992 snprintf(buf, 32, "domain%d", i); 4993 entry->procname = kstrdup(buf, GFP_KERNEL); 4994 entry->mode = 0555; 4995 entry->child = sd_alloc_ctl_domain_table(sd); 4996 entry++; 4997 i++; 4998 } 4999 return table; 5000} 5001 5002static struct ctl_table_header *sd_sysctl_header; 5003static void register_sched_domain_sysctl(void) 5004{ 5005 int i, cpu_num = num_possible_cpus(); 5006 struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1); 5007 char buf[32]; 5008 5009 WARN_ON(sd_ctl_dir[0].child); 5010 sd_ctl_dir[0].child = entry; 5011 5012 if (entry == NULL) 5013 return; 5014 5015 for_each_possible_cpu(i) { 5016 snprintf(buf, 32, "cpu%d", i); 5017 entry->procname = kstrdup(buf, GFP_KERNEL); 5018 entry->mode = 0555; 5019 entry->child = sd_alloc_ctl_cpu_table(i); 5020 entry++; 5021 } 5022 5023 WARN_ON(sd_sysctl_header); 5024 sd_sysctl_header = register_sysctl_table(sd_ctl_root); 5025} 5026 5027/* may be called multiple times per register */ 5028static void unregister_sched_domain_sysctl(void) 5029{ 5030 if (sd_sysctl_header) 5031 unregister_sysctl_table(sd_sysctl_header); 5032 sd_sysctl_header = NULL; 5033 if (sd_ctl_dir[0].child) 5034 sd_free_ctl_entry(&sd_ctl_dir[0].child); 5035} 5036#else 5037static void register_sched_domain_sysctl(void) 5038{ 5039} 5040static void unregister_sched_domain_sysctl(void) 5041{ 5042} 5043#endif 5044 5045static void set_rq_online(struct rq *rq) 5046{ 5047 if (!rq->online) { 5048 const struct sched_class *class; 5049 5050 cpumask_set_cpu(rq->cpu, rq->rd->online); 5051 rq->online = 1; 5052 5053 for_each_class(class) { 5054 if (class->rq_online) 5055 class->rq_online(rq); 5056 } 5057 } 5058} 5059 5060static void set_rq_offline(struct rq *rq) 5061{ 5062 if (rq->online) { 5063 const struct sched_class *class; 5064 5065 for_each_class(class) { 5066 if (class->rq_offline) 5067 class->rq_offline(rq); 5068 } 5069 5070 cpumask_clear_cpu(rq->cpu, rq->rd->online); 5071 rq->online = 0; 5072 } 5073} 5074 5075/* 5076 * migration_call - callback that gets triggered when a CPU is added. 5077 * Here we can start up the necessary migration thread for the new CPU. 5078 */ 5079static int 5080migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) 5081{ 5082 int cpu = (long)hcpu; 5083 unsigned long flags; 5084 struct rq *rq = cpu_rq(cpu); 5085 5086 switch (action & ~CPU_TASKS_FROZEN) { 5087 5088 case CPU_UP_PREPARE: 5089 rq->calc_load_update = calc_load_update; 5090 break; 5091 5092 case CPU_ONLINE: 5093 /* Update our root-domain */ 5094 raw_spin_lock_irqsave(&rq->lock, flags); 5095 if (rq->rd) { 5096 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); 5097 5098 set_rq_online(rq); 5099 } 5100 raw_spin_unlock_irqrestore(&rq->lock, flags); 5101 break; 5102 5103#ifdef CONFIG_HOTPLUG_CPU 5104 case CPU_DYING: 5105 sched_ttwu_pending(); 5106 /* Update our root-domain */ 5107 raw_spin_lock_irqsave(&rq->lock, flags); 5108 if (rq->rd) { 5109 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); 5110 set_rq_offline(rq); 5111 } 5112 migrate_tasks(cpu); 5113 BUG_ON(rq->nr_running != 1); /* the migration thread */ 5114 raw_spin_unlock_irqrestore(&rq->lock, flags); 5115 break; 5116 5117 case CPU_DEAD: 5118 calc_load_migrate(rq); 5119 break; 5120#endif 5121 } 5122 5123 update_max_interval(); 5124 5125 return NOTIFY_OK; 5126} 5127 5128/* 5129 * Register at high priority so that task migration (migrate_all_tasks) 5130 * happens before everything else. This has to be lower priority than 5131 * the notifier in the perf_event subsystem, though. 5132 */ 5133static struct notifier_block migration_notifier = { 5134 .notifier_call = migration_call, 5135 .priority = CPU_PRI_MIGRATION, 5136}; 5137 5138static void __cpuinit set_cpu_rq_start_time(void) 5139{ 5140 int cpu = smp_processor_id(); 5141 struct rq *rq = cpu_rq(cpu); 5142 rq->age_stamp = sched_clock_cpu(cpu); 5143} 5144 5145static int sched_cpu_active(struct notifier_block *nfb, 5146 unsigned long action, void *hcpu) 5147{ 5148 switch (action & ~CPU_TASKS_FROZEN) { 5149 case CPU_STARTING: 5150 set_cpu_rq_start_time(); 5151 return NOTIFY_OK; 5152 case CPU_DOWN_FAILED: 5153 set_cpu_active((long)hcpu, true); 5154 return NOTIFY_OK; 5155 default: 5156 return NOTIFY_DONE; 5157 } 5158} 5159 5160static int sched_cpu_inactive(struct notifier_block *nfb, 5161 unsigned long action, void *hcpu) 5162{ 5163 unsigned long flags; 5164 long cpu = (long)hcpu; 5165 5166 switch (action & ~CPU_TASKS_FROZEN) { 5167 case CPU_DOWN_PREPARE: 5168 set_cpu_active(cpu, false); 5169 5170 /* explicitly allow suspend */ 5171 if (!(action & CPU_TASKS_FROZEN)) { 5172 struct dl_bw *dl_b = dl_bw_of(cpu); 5173 bool overflow; 5174 int cpus; 5175 5176 raw_spin_lock_irqsave(&dl_b->lock, flags); 5177 cpus = dl_bw_cpus(cpu); 5178 overflow = __dl_overflow(dl_b, cpus, 0, 0); 5179 raw_spin_unlock_irqrestore(&dl_b->lock, flags); 5180 5181 if (overflow) 5182 return notifier_from_errno(-EBUSY); 5183 } 5184 return NOTIFY_OK; 5185 } 5186 5187 return NOTIFY_DONE; 5188} 5189 5190static int __init migration_init(void) 5191{ 5192 void *cpu = (void *)(long)smp_processor_id(); 5193 int err; 5194 5195 /* Initialize migration for the boot CPU */ 5196 err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); 5197 BUG_ON(err == NOTIFY_BAD); 5198 migration_call(&migration_notifier, CPU_ONLINE, cpu); 5199 register_cpu_notifier(&migration_notifier); 5200 5201 /* Register cpu active notifiers */ 5202 cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE); 5203 cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE); 5204 5205 return 0; 5206} 5207early_initcall(migration_init); 5208#endif 5209 5210#ifdef CONFIG_SMP 5211 5212static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */ 5213 5214#ifdef CONFIG_SCHED_DEBUG 5215 5216static __read_mostly int sched_debug_enabled; 5217 5218static int __init sched_debug_setup(char *str) 5219{ 5220 sched_debug_enabled = 1; 5221 5222 return 0; 5223} 5224early_param("sched_debug", sched_debug_setup); 5225 5226static inline bool sched_debug(void) 5227{ 5228 return sched_debug_enabled; 5229} 5230 5231static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, 5232 struct cpumask *groupmask) 5233{ 5234 struct sched_group *group = sd->groups; 5235 char str[256]; 5236 5237 cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd)); 5238 cpumask_clear(groupmask); 5239 5240 printk(KERN_DEBUG "%*s domain %d: ", level, "", level); 5241 5242 if (!(sd->flags & SD_LOAD_BALANCE)) { 5243 printk("does not load-balance\n"); 5244 if (sd->parent) 5245 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain" 5246 " has parent"); 5247 return -1; 5248 } 5249 5250 printk(KERN_CONT "span %s level %s\n", str, sd->name); 5251 5252 if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) { 5253 printk(KERN_ERR "ERROR: domain->span does not contain " 5254 "CPU%d\n", cpu); 5255 } 5256 if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) { 5257 printk(KERN_ERR "ERROR: domain->groups does not contain" 5258 " CPU%d\n", cpu); 5259 } 5260 5261 printk(KERN_DEBUG "%*s groups:", level + 1, ""); 5262 do { 5263 if (!group) { 5264 printk("\n"); 5265 printk(KERN_ERR "ERROR: group is NULL\n"); 5266 break; 5267 } 5268 5269 /* 5270 * Even though we initialize ->capacity to something semi-sane, 5271 * we leave capacity_orig unset. This allows us to detect if 5272 * domain iteration is still funny without causing /0 traps. 5273 */ 5274 if (!group->sgc->capacity_orig) { 5275 printk(KERN_CONT "\n"); 5276 printk(KERN_ERR "ERROR: domain->cpu_capacity not set\n"); 5277 break; 5278 } 5279 5280 if (!cpumask_weight(sched_group_cpus(group))) { 5281 printk(KERN_CONT "\n"); 5282 printk(KERN_ERR "ERROR: empty group\n"); 5283 break; 5284 } 5285 5286 if (!(sd->flags & SD_OVERLAP) && 5287 cpumask_intersects(groupmask, sched_group_cpus(group))) { 5288 printk(KERN_CONT "\n"); 5289 printk(KERN_ERR "ERROR: repeated CPUs\n"); 5290 break; 5291 } 5292 5293 cpumask_or(groupmask, groupmask, sched_group_cpus(group)); 5294 5295 cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group)); 5296 5297 printk(KERN_CONT " %s", str); 5298 if (group->sgc->capacity != SCHED_CAPACITY_SCALE) { 5299 printk(KERN_CONT " (cpu_capacity = %d)", 5300 group->sgc->capacity); 5301 } 5302 5303 group = group->next; 5304 } while (group != sd->groups); 5305 printk(KERN_CONT "\n"); 5306 5307 if (!cpumask_equal(sched_domain_span(sd), groupmask)) 5308 printk(KERN_ERR "ERROR: groups don't span domain->span\n"); 5309 5310 if (sd->parent && 5311 !cpumask_subset(groupmask, sched_domain_span(sd->parent))) 5312 printk(KERN_ERR "ERROR: parent span is not a superset " 5313 "of domain->span\n"); 5314 return 0; 5315} 5316 5317static void sched_domain_debug(struct sched_domain *sd, int cpu) 5318{ 5319 int level = 0; 5320 5321 if (!sched_debug_enabled) 5322 return; 5323 5324 if (!sd) { 5325 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); 5326 return; 5327 } 5328 5329 printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); 5330 5331 for (;;) { 5332 if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask)) 5333 break; 5334 level++; 5335 sd = sd->parent; 5336 if (!sd) 5337 break; 5338 } 5339} 5340#else /* !CONFIG_SCHED_DEBUG */ 5341# define sched_domain_debug(sd, cpu) do { } while (0) 5342static inline bool sched_debug(void) 5343{ 5344 return false; 5345} 5346#endif /* CONFIG_SCHED_DEBUG */ 5347 5348static int sd_degenerate(struct sched_domain *sd) 5349{ 5350 if (cpumask_weight(sched_domain_span(sd)) == 1) 5351 return 1; 5352 5353 /* Following flags need at least 2 groups */ 5354 if (sd->flags & (SD_LOAD_BALANCE | 5355 SD_BALANCE_NEWIDLE | 5356 SD_BALANCE_FORK | 5357 SD_BALANCE_EXEC | 5358 SD_SHARE_CPUCAPACITY | 5359 SD_SHARE_PKG_RESOURCES | 5360 SD_SHARE_POWERDOMAIN)) { 5361 if (sd->groups != sd->groups->next) 5362 return 0; 5363 } 5364 5365 /* Following flags don't use groups */ 5366 if (sd->flags & (SD_WAKE_AFFINE)) 5367 return 0; 5368 5369 return 1; 5370} 5371 5372static int 5373sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) 5374{ 5375 unsigned long cflags = sd->flags, pflags = parent->flags; 5376 5377 if (sd_degenerate(parent)) 5378 return 1; 5379 5380 if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent))) 5381 return 0; 5382 5383 /* Flags needing groups don't count if only 1 group in parent */ 5384 if (parent->groups == parent->groups->next) { 5385 pflags &= ~(SD_LOAD_BALANCE | 5386 SD_BALANCE_NEWIDLE | 5387 SD_BALANCE_FORK | 5388 SD_BALANCE_EXEC | 5389 SD_SHARE_CPUCAPACITY | 5390 SD_SHARE_PKG_RESOURCES | 5391 SD_PREFER_SIBLING | 5392 SD_SHARE_POWERDOMAIN); 5393 if (nr_node_ids == 1) 5394 pflags &= ~SD_SERIALIZE; 5395 } 5396 if (~cflags & pflags) 5397 return 0; 5398 5399 return 1; 5400} 5401 5402static void free_rootdomain(struct rcu_head *rcu) 5403{ 5404 struct root_domain *rd = container_of(rcu, struct root_domain, rcu); 5405 5406 cpupri_cleanup(&rd->cpupri); 5407 cpudl_cleanup(&rd->cpudl); 5408 free_cpumask_var(rd->dlo_mask); 5409 free_cpumask_var(rd->rto_mask); 5410 free_cpumask_var(rd->online); 5411 free_cpumask_var(rd->span); 5412 kfree(rd); 5413} 5414 5415static void rq_attach_root(struct rq *rq, struct root_domain *rd) 5416{ 5417 struct root_domain *old_rd = NULL; 5418 unsigned long flags; 5419 5420 raw_spin_lock_irqsave(&rq->lock, flags); 5421 5422 if (rq->rd) { 5423 old_rd = rq->rd; 5424 5425 if (cpumask_test_cpu(rq->cpu, old_rd->online)) 5426 set_rq_offline(rq); 5427 5428 cpumask_clear_cpu(rq->cpu, old_rd->span); 5429 5430 /* 5431 * If we dont want to free the old_rd yet then 5432 * set old_rd to NULL to skip the freeing later 5433 * in this function: 5434 */ 5435 if (!atomic_dec_and_test(&old_rd->refcount)) 5436 old_rd = NULL; 5437 } 5438 5439 atomic_inc(&rd->refcount); 5440 rq->rd = rd; 5441 5442 cpumask_set_cpu(rq->cpu, rd->span); 5443 if (cpumask_test_cpu(rq->cpu, cpu_active_mask)) 5444 set_rq_online(rq); 5445 5446 raw_spin_unlock_irqrestore(&rq->lock, flags); 5447 5448 if (old_rd) 5449 call_rcu_sched(&old_rd->rcu, free_rootdomain); 5450} 5451 5452static int init_rootdomain(struct root_domain *rd) 5453{ 5454 memset(rd, 0, sizeof(*rd)); 5455 5456 if (!alloc_cpumask_var(&rd->span, GFP_KERNEL)) 5457 goto out; 5458 if (!alloc_cpumask_var(&rd->online, GFP_KERNEL)) 5459 goto free_span; 5460 if (!alloc_cpumask_var(&rd->dlo_mask, GFP_KERNEL)) 5461 goto free_online; 5462 if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL)) 5463 goto free_dlo_mask; 5464 5465 init_dl_bw(&rd->dl_bw); 5466 if (cpudl_init(&rd->cpudl) != 0) 5467 goto free_dlo_mask; 5468 5469 if (cpupri_init(&rd->cpupri) != 0) 5470 goto free_rto_mask; 5471 return 0; 5472 5473free_rto_mask: 5474 free_cpumask_var(rd->rto_mask); 5475free_dlo_mask: 5476 free_cpumask_var(rd->dlo_mask); 5477free_online: 5478 free_cpumask_var(rd->online); 5479free_span: 5480 free_cpumask_var(rd->span); 5481out: 5482 return -ENOMEM; 5483} 5484 5485/* 5486 * By default the system creates a single root-domain with all cpus as 5487 * members (mimicking the global state we have today). 5488 */ 5489struct root_domain def_root_domain; 5490 5491static void init_defrootdomain(void) 5492{ 5493 init_rootdomain(&def_root_domain); 5494 5495 atomic_set(&def_root_domain.refcount, 1); 5496} 5497 5498static struct root_domain *alloc_rootdomain(void) 5499{ 5500 struct root_domain *rd; 5501 5502 rd = kmalloc(sizeof(*rd), GFP_KERNEL); 5503 if (!rd) 5504 return NULL; 5505 5506 if (init_rootdomain(rd) != 0) { 5507 kfree(rd); 5508 return NULL; 5509 } 5510 5511 return rd; 5512} 5513 5514static void free_sched_groups(struct sched_group *sg, int free_sgc) 5515{ 5516 struct sched_group *tmp, *first; 5517 5518 if (!sg) 5519 return; 5520 5521 first = sg; 5522 do { 5523 tmp = sg->next; 5524 5525 if (free_sgc && atomic_dec_and_test(&sg->sgc->ref)) 5526 kfree(sg->sgc); 5527 5528 kfree(sg); 5529 sg = tmp; 5530 } while (sg != first); 5531} 5532 5533static void free_sched_domain(struct rcu_head *rcu) 5534{ 5535 struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu); 5536 5537 /* 5538 * If its an overlapping domain it has private groups, iterate and 5539 * nuke them all. 5540 */ 5541 if (sd->flags & SD_OVERLAP) { 5542 free_sched_groups(sd->groups, 1); 5543 } else if (atomic_dec_and_test(&sd->groups->ref)) { 5544 kfree(sd->groups->sgc); 5545 kfree(sd->groups); 5546 } 5547 kfree(sd); 5548} 5549 5550static void destroy_sched_domain(struct sched_domain *sd, int cpu) 5551{ 5552 call_rcu(&sd->rcu, free_sched_domain); 5553} 5554 5555static void destroy_sched_domains(struct sched_domain *sd, int cpu) 5556{ 5557 for (; sd; sd = sd->parent) 5558 destroy_sched_domain(sd, cpu); 5559} 5560 5561/* 5562 * Keep a special pointer to the highest sched_domain that has 5563 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this 5564 * allows us to avoid some pointer chasing select_idle_sibling(). 5565 * 5566 * Also keep a unique ID per domain (we use the first cpu number in 5567 * the cpumask of the domain), this allows us to quickly tell if 5568 * two cpus are in the same cache domain, see cpus_share_cache(). 5569 */ 5570DEFINE_PER_CPU(struct sched_domain *, sd_llc); 5571DEFINE_PER_CPU(int, sd_llc_size); 5572DEFINE_PER_CPU(int, sd_llc_id); 5573DEFINE_PER_CPU(struct sched_domain *, sd_numa); 5574DEFINE_PER_CPU(struct sched_domain *, sd_busy); 5575DEFINE_PER_CPU(struct sched_domain *, sd_asym); 5576 5577static void update_top_cache_domain(int cpu) 5578{ 5579 struct sched_domain *sd; 5580 struct sched_domain *busy_sd = NULL; 5581 int id = cpu; 5582 int size = 1; 5583 5584 sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES); 5585 if (sd) { 5586 id = cpumask_first(sched_domain_span(sd)); 5587 size = cpumask_weight(sched_domain_span(sd)); 5588 busy_sd = sd->parent; /* sd_busy */ 5589 } 5590 rcu_assign_pointer(per_cpu(sd_busy, cpu), busy_sd); 5591 5592 rcu_assign_pointer(per_cpu(sd_llc, cpu), sd); 5593 per_cpu(sd_llc_size, cpu) = size; 5594 per_cpu(sd_llc_id, cpu) = id; 5595 5596 sd = lowest_flag_domain(cpu, SD_NUMA); 5597 rcu_assign_pointer(per_cpu(sd_numa, cpu), sd); 5598 5599 sd = highest_flag_domain(cpu, SD_ASYM_PACKING); 5600 rcu_assign_pointer(per_cpu(sd_asym, cpu), sd); 5601} 5602 5603/* 5604 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must 5605 * hold the hotplug lock. 5606 */ 5607static void 5608cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) 5609{ 5610 struct rq *rq = cpu_rq(cpu); 5611 struct sched_domain *tmp; 5612 5613 /* Remove the sched domains which do not contribute to scheduling. */ 5614 for (tmp = sd; tmp; ) { 5615 struct sched_domain *parent = tmp->parent; 5616 if (!parent) 5617 break; 5618 5619 if (sd_parent_degenerate(tmp, parent)) { 5620 tmp->parent = parent->parent; 5621 if (parent->parent) 5622 parent->parent->child = tmp; 5623 /* 5624 * Transfer SD_PREFER_SIBLING down in case of a 5625 * degenerate parent; the spans match for this 5626 * so the property transfers. 5627 */ 5628 if (parent->flags & SD_PREFER_SIBLING) 5629 tmp->flags |= SD_PREFER_SIBLING; 5630 destroy_sched_domain(parent, cpu); 5631 } else 5632 tmp = tmp->parent; 5633 } 5634 5635 if (sd && sd_degenerate(sd)) { 5636 tmp = sd; 5637 sd = sd->parent; 5638 destroy_sched_domain(tmp, cpu); 5639 if (sd) 5640 sd->child = NULL; 5641 } 5642 5643 sched_domain_debug(sd, cpu); 5644 5645 rq_attach_root(rq, rd); 5646 tmp = rq->sd; 5647 rcu_assign_pointer(rq->sd, sd); 5648 destroy_sched_domains(tmp, cpu); 5649 5650 update_top_cache_domain(cpu); 5651} 5652 5653/* cpus with isolated domains */ 5654static cpumask_var_t cpu_isolated_map; 5655 5656/* Setup the mask of cpus configured for isolated domains */ 5657static int __init isolated_cpu_setup(char *str) 5658{ 5659 alloc_bootmem_cpumask_var(&cpu_isolated_map); 5660 cpulist_parse(str, cpu_isolated_map); 5661 return 1; 5662} 5663 5664__setup("isolcpus=", isolated_cpu_setup); 5665 5666struct s_data { 5667 struct sched_domain ** __percpu sd; 5668 struct root_domain *rd; 5669}; 5670 5671enum s_alloc { 5672 sa_rootdomain, 5673 sa_sd, 5674 sa_sd_storage, 5675 sa_none, 5676}; 5677 5678/* 5679 * Build an iteration mask that can exclude certain CPUs from the upwards 5680 * domain traversal. 5681 * 5682 * Asymmetric node setups can result in situations where the domain tree is of 5683 * unequal depth, make sure to skip domains that already cover the entire 5684 * range. 5685 * 5686 * In that case build_sched_domains() will have terminated the iteration early 5687 * and our sibling sd spans will be empty. Domains should always include the 5688 * cpu they're built on, so check that. 5689 * 5690 */ 5691static void build_group_mask(struct sched_domain *sd, struct sched_group *sg) 5692{ 5693 const struct cpumask *span = sched_domain_span(sd); 5694 struct sd_data *sdd = sd->private; 5695 struct sched_domain *sibling; 5696 int i; 5697 5698 for_each_cpu(i, span) { 5699 sibling = *per_cpu_ptr(sdd->sd, i); 5700 if (!cpumask_test_cpu(i, sched_domain_span(sibling))) 5701 continue; 5702 5703 cpumask_set_cpu(i, sched_group_mask(sg)); 5704 } 5705} 5706 5707/* 5708 * Return the canonical balance cpu for this group, this is the first cpu 5709 * of this group that's also in the iteration mask. 5710 */ 5711int group_balance_cpu(struct sched_group *sg) 5712{ 5713 return cpumask_first_and(sched_group_cpus(sg), sched_group_mask(sg)); 5714} 5715 5716static int 5717build_overlap_sched_groups(struct sched_domain *sd, int cpu) 5718{ 5719 struct sched_group *first = NULL, *last = NULL, *groups = NULL, *sg; 5720 const struct cpumask *span = sched_domain_span(sd); 5721 struct cpumask *covered = sched_domains_tmpmask; 5722 struct sd_data *sdd = sd->private; 5723 struct sched_domain *child; 5724 int i; 5725 5726 cpumask_clear(covered); 5727 5728 for_each_cpu(i, span) { 5729 struct cpumask *sg_span; 5730 5731 if (cpumask_test_cpu(i, covered)) 5732 continue; 5733 5734 child = *per_cpu_ptr(sdd->sd, i); 5735 5736 /* See the comment near build_group_mask(). */ 5737 if (!cpumask_test_cpu(i, sched_domain_span(child))) 5738 continue; 5739 5740 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), 5741 GFP_KERNEL, cpu_to_node(cpu)); 5742 5743 if (!sg) 5744 goto fail; 5745 5746 sg_span = sched_group_cpus(sg); 5747 if (child->child) { 5748 child = child->child; 5749 cpumask_copy(sg_span, sched_domain_span(child)); 5750 } else 5751 cpumask_set_cpu(i, sg_span); 5752 5753 cpumask_or(covered, covered, sg_span); 5754 5755 sg->sgc = *per_cpu_ptr(sdd->sgc, i); 5756 if (atomic_inc_return(&sg->sgc->ref) == 1) 5757 build_group_mask(sd, sg); 5758 5759 /* 5760 * Initialize sgc->capacity such that even if we mess up the 5761 * domains and no possible iteration will get us here, we won't 5762 * die on a /0 trap. 5763 */ 5764 sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sg_span); 5765 sg->sgc->capacity_orig = sg->sgc->capacity; 5766 5767 /* 5768 * Make sure the first group of this domain contains the 5769 * canonical balance cpu. Otherwise the sched_domain iteration 5770 * breaks. See update_sg_lb_stats(). 5771 */ 5772 if ((!groups && cpumask_test_cpu(cpu, sg_span)) || 5773 group_balance_cpu(sg) == cpu) 5774 groups = sg; 5775 5776 if (!first) 5777 first = sg; 5778 if (last) 5779 last->next = sg; 5780 last = sg; 5781 last->next = first; 5782 } 5783 sd->groups = groups; 5784 5785 return 0; 5786 5787fail: 5788 free_sched_groups(first, 0); 5789 5790 return -ENOMEM; 5791} 5792 5793static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg) 5794{ 5795 struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu); 5796 struct sched_domain *child = sd->child; 5797 5798 if (child) 5799 cpu = cpumask_first(sched_domain_span(child)); 5800 5801 if (sg) { 5802 *sg = *per_cpu_ptr(sdd->sg, cpu); 5803 (*sg)->sgc = *per_cpu_ptr(sdd->sgc, cpu); 5804 atomic_set(&(*sg)->sgc->ref, 1); /* for claim_allocations */ 5805 } 5806 5807 return cpu; 5808} 5809 5810/* 5811 * build_sched_groups will build a circular linked list of the groups 5812 * covered by the given span, and will set each group's ->cpumask correctly, 5813 * and ->cpu_capacity to 0. 5814 * 5815 * Assumes the sched_domain tree is fully constructed 5816 */ 5817static int 5818build_sched_groups(struct sched_domain *sd, int cpu) 5819{ 5820 struct sched_group *first = NULL, *last = NULL; 5821 struct sd_data *sdd = sd->private; 5822 const struct cpumask *span = sched_domain_span(sd); 5823 struct cpumask *covered; 5824 int i; 5825 5826 get_group(cpu, sdd, &sd->groups); 5827 atomic_inc(&sd->groups->ref); 5828 5829 if (cpu != cpumask_first(span)) 5830 return 0; 5831 5832 lockdep_assert_held(&sched_domains_mutex); 5833 covered = sched_domains_tmpmask; 5834 5835 cpumask_clear(covered); 5836 5837 for_each_cpu(i, span) { 5838 struct sched_group *sg; 5839 int group, j; 5840 5841 if (cpumask_test_cpu(i, covered)) 5842 continue; 5843 5844 group = get_group(i, sdd, &sg); 5845 cpumask_setall(sched_group_mask(sg)); 5846 5847 for_each_cpu(j, span) { 5848 if (get_group(j, sdd, NULL) != group) 5849 continue; 5850 5851 cpumask_set_cpu(j, covered); 5852 cpumask_set_cpu(j, sched_group_cpus(sg)); 5853 } 5854 5855 if (!first) 5856 first = sg; 5857 if (last) 5858 last->next = sg; 5859 last = sg; 5860 } 5861 last->next = first; 5862 5863 return 0; 5864} 5865 5866/* 5867 * Initialize sched groups cpu_capacity. 5868 * 5869 * cpu_capacity indicates the capacity of sched group, which is used while 5870 * distributing the load between different sched groups in a sched domain. 5871 * Typically cpu_capacity for all the groups in a sched domain will be same 5872 * unless there are asymmetries in the topology. If there are asymmetries, 5873 * group having more cpu_capacity will pickup more load compared to the 5874 * group having less cpu_capacity. 5875 */ 5876static void init_sched_groups_capacity(int cpu, struct sched_domain *sd) 5877{ 5878 struct sched_group *sg = sd->groups; 5879 5880 WARN_ON(!sg); 5881 5882 do { 5883 sg->group_weight = cpumask_weight(sched_group_cpus(sg)); 5884 sg = sg->next; 5885 } while (sg != sd->groups); 5886 5887 if (cpu != group_balance_cpu(sg)) 5888 return; 5889 5890 update_group_capacity(sd, cpu); 5891 atomic_set(&sg->sgc->nr_busy_cpus, sg->group_weight); 5892} 5893 5894/* 5895 * Initializers for schedule domains 5896 * Non-inlined to reduce accumulated stack pressure in build_sched_domains() 5897 */ 5898 5899static int default_relax_domain_level = -1; 5900int sched_domain_level_max; 5901 5902static int __init setup_relax_domain_level(char *str) 5903{ 5904 if (kstrtoint(str, 0, &default_relax_domain_level)) 5905 pr_warn("Unable to set relax_domain_level\n"); 5906 5907 return 1; 5908} 5909__setup("relax_domain_level=", setup_relax_domain_level); 5910 5911static void set_domain_attribute(struct sched_domain *sd, 5912 struct sched_domain_attr *attr) 5913{ 5914 int request; 5915 5916 if (!attr || attr->relax_domain_level < 0) { 5917 if (default_relax_domain_level < 0) 5918 return; 5919 else 5920 request = default_relax_domain_level; 5921 } else 5922 request = attr->relax_domain_level; 5923 if (request < sd->level) { 5924 /* turn off idle balance on this domain */ 5925 sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); 5926 } else { 5927 /* turn on idle balance on this domain */ 5928 sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); 5929 } 5930} 5931 5932static void __sdt_free(const struct cpumask *cpu_map); 5933static int __sdt_alloc(const struct cpumask *cpu_map); 5934 5935static void __free_domain_allocs(struct s_data *d, enum s_alloc what, 5936 const struct cpumask *cpu_map) 5937{ 5938 switch (what) { 5939 case sa_rootdomain: 5940 if (!atomic_read(&d->rd->refcount)) 5941 free_rootdomain(&d->rd->rcu); /* fall through */ 5942 case sa_sd: 5943 free_percpu(d->sd); /* fall through */ 5944 case sa_sd_storage: 5945 __sdt_free(cpu_map); /* fall through */ 5946 case sa_none: 5947 break; 5948 } 5949} 5950 5951static enum s_alloc __visit_domain_allocation_hell(struct s_data *d, 5952 const struct cpumask *cpu_map) 5953{ 5954 memset(d, 0, sizeof(*d)); 5955 5956 if (__sdt_alloc(cpu_map)) 5957 return sa_sd_storage; 5958 d->sd = alloc_percpu(struct sched_domain *); 5959 if (!d->sd) 5960 return sa_sd_storage; 5961 d->rd = alloc_rootdomain(); 5962 if (!d->rd) 5963 return sa_sd; 5964 return sa_rootdomain; 5965} 5966 5967/* 5968 * NULL the sd_data elements we've used to build the sched_domain and 5969 * sched_group structure so that the subsequent __free_domain_allocs() 5970 * will not free the data we're using. 5971 */ 5972static void claim_allocations(int cpu, struct sched_domain *sd) 5973{ 5974 struct sd_data *sdd = sd->private; 5975 5976 WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd); 5977 *per_cpu_ptr(sdd->sd, cpu) = NULL; 5978 5979 if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref)) 5980 *per_cpu_ptr(sdd->sg, cpu) = NULL; 5981 5982 if (atomic_read(&(*per_cpu_ptr(sdd->sgc, cpu))->ref)) 5983 *per_cpu_ptr(sdd->sgc, cpu) = NULL; 5984} 5985 5986#ifdef CONFIG_NUMA 5987static int sched_domains_numa_levels; 5988static int *sched_domains_numa_distance; 5989static struct cpumask ***sched_domains_numa_masks; 5990static int sched_domains_curr_level; 5991#endif 5992 5993/* 5994 * SD_flags allowed in topology descriptions. 5995 * 5996 * SD_SHARE_CPUCAPACITY - describes SMT topologies 5997 * SD_SHARE_PKG_RESOURCES - describes shared caches 5998 * SD_NUMA - describes NUMA topologies 5999 * SD_SHARE_POWERDOMAIN - describes shared power domain 6000 * 6001 * Odd one out: 6002 * SD_ASYM_PACKING - describes SMT quirks 6003 */ 6004#define TOPOLOGY_SD_FLAGS \ 6005 (SD_SHARE_CPUCAPACITY | \ 6006 SD_SHARE_PKG_RESOURCES | \ 6007 SD_NUMA | \ 6008 SD_ASYM_PACKING | \ 6009 SD_SHARE_POWERDOMAIN) 6010 6011static struct sched_domain * 6012sd_init(struct sched_domain_topology_level *tl, int cpu) 6013{ 6014 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); 6015 int sd_weight, sd_flags = 0; 6016 6017#ifdef CONFIG_NUMA 6018 /* 6019 * Ugly hack to pass state to sd_numa_mask()... 6020 */ 6021 sched_domains_curr_level = tl->numa_level; 6022#endif 6023 6024 sd_weight = cpumask_weight(tl->mask(cpu)); 6025 6026 if (tl->sd_flags) 6027 sd_flags = (*tl->sd_flags)(); 6028 if (WARN_ONCE(sd_flags & ~TOPOLOGY_SD_FLAGS, 6029 "wrong sd_flags in topology description\n")) 6030 sd_flags &= ~TOPOLOGY_SD_FLAGS; 6031 6032 *sd = (struct sched_domain){ 6033 .min_interval = sd_weight, 6034 .max_interval = 2*sd_weight, 6035 .busy_factor = 32, 6036 .imbalance_pct = 125, 6037 6038 .cache_nice_tries = 0, 6039 .busy_idx = 0, 6040 .idle_idx = 0, 6041 .newidle_idx = 0, 6042 .wake_idx = 0, 6043 .forkexec_idx = 0, 6044 6045 .flags = 1*SD_LOAD_BALANCE 6046 | 1*SD_BALANCE_NEWIDLE 6047 | 1*SD_BALANCE_EXEC 6048 | 1*SD_BALANCE_FORK 6049 | 0*SD_BALANCE_WAKE 6050 | 1*SD_WAKE_AFFINE 6051 | 0*SD_SHARE_CPUCAPACITY 6052 | 0*SD_SHARE_PKG_RESOURCES 6053 | 0*SD_SERIALIZE 6054 | 0*SD_PREFER_SIBLING 6055 | 0*SD_NUMA 6056 | sd_flags 6057 , 6058 6059 .last_balance = jiffies, 6060 .balance_interval = sd_weight, 6061 .smt_gain = 0, 6062 .max_newidle_lb_cost = 0, 6063 .next_decay_max_lb_cost = jiffies, 6064#ifdef CONFIG_SCHED_DEBUG 6065 .name = tl->name, 6066#endif 6067 }; 6068 6069 /* 6070 * Convert topological properties into behaviour. 6071 */ 6072 6073 if (sd->flags & SD_SHARE_CPUCAPACITY) { 6074 sd->imbalance_pct = 110; 6075 sd->smt_gain = 1178; /* ~15% */ 6076 6077 } else if (sd->flags & SD_SHARE_PKG_RESOURCES) { 6078 sd->imbalance_pct = 117; 6079 sd->cache_nice_tries = 1; 6080 sd->busy_idx = 2; 6081 6082#ifdef CONFIG_NUMA 6083 } else if (sd->flags & SD_NUMA) { 6084 sd->cache_nice_tries = 2; 6085 sd->busy_idx = 3; 6086 sd->idle_idx = 2; 6087 6088 sd->flags |= SD_SERIALIZE; 6089 if (sched_domains_numa_distance[tl->numa_level] > RECLAIM_DISTANCE) { 6090 sd->flags &= ~(SD_BALANCE_EXEC | 6091 SD_BALANCE_FORK | 6092 SD_WAKE_AFFINE); 6093 } 6094 6095#endif 6096 } else { 6097 sd->flags |= SD_PREFER_SIBLING; 6098 sd->cache_nice_tries = 1; 6099 sd->busy_idx = 2; 6100 sd->idle_idx = 1; 6101 } 6102 6103 sd->private = &tl->data; 6104 6105 return sd; 6106} 6107 6108/* 6109 * Topology list, bottom-up. 6110 */ 6111static struct sched_domain_topology_level default_topology[] = { 6112#ifdef CONFIG_SCHED_SMT 6113 { cpu_smt_mask, cpu_smt_flags, SD_INIT_NAME(SMT) }, 6114#endif 6115#ifdef CONFIG_SCHED_MC 6116 { cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) }, 6117#endif 6118 { cpu_cpu_mask, SD_INIT_NAME(DIE) }, 6119 { NULL, }, 6120}; 6121 6122struct sched_domain_topology_level *sched_domain_topology = default_topology; 6123 6124#define for_each_sd_topology(tl) \ 6125 for (tl = sched_domain_topology; tl->mask; tl++) 6126 6127void set_sched_topology(struct sched_domain_topology_level *tl) 6128{ 6129 sched_domain_topology = tl; 6130} 6131 6132#ifdef CONFIG_NUMA 6133 6134static const struct cpumask *sd_numa_mask(int cpu) 6135{ 6136 return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)]; 6137} 6138 6139static void sched_numa_warn(const char *str) 6140{ 6141 static int done = false; 6142 int i,j; 6143 6144 if (done) 6145 return; 6146 6147 done = true; 6148 6149 printk(KERN_WARNING "ERROR: %s\n\n", str); 6150 6151 for (i = 0; i < nr_node_ids; i++) { 6152 printk(KERN_WARNING " "); 6153 for (j = 0; j < nr_node_ids; j++) 6154 printk(KERN_CONT "%02d ", node_distance(i,j)); 6155 printk(KERN_CONT "\n"); 6156 } 6157 printk(KERN_WARNING "\n"); 6158} 6159 6160static bool find_numa_distance(int distance) 6161{ 6162 int i; 6163 6164 if (distance == node_distance(0, 0)) 6165 return true; 6166 6167 for (i = 0; i < sched_domains_numa_levels; i++) { 6168 if (sched_domains_numa_distance[i] == distance) 6169 return true; 6170 } 6171 6172 return false; 6173} 6174 6175static void sched_init_numa(void) 6176{ 6177 int next_distance, curr_distance = node_distance(0, 0); 6178 struct sched_domain_topology_level *tl; 6179 int level = 0; 6180 int i, j, k; 6181 6182 sched_domains_numa_distance = kzalloc(sizeof(int) * nr_node_ids, GFP_KERNEL); 6183 if (!sched_domains_numa_distance) 6184 return; 6185 6186 /* 6187 * O(nr_nodes^2) deduplicating selection sort -- in order to find the 6188 * unique distances in the node_distance() table. 6189 * 6190 * Assumes node_distance(0,j) includes all distances in 6191 * node_distance(i,j) in order to avoid cubic time. 6192 */ 6193 next_distance = curr_distance; 6194 for (i = 0; i < nr_node_ids; i++) { 6195 for (j = 0; j < nr_node_ids; j++) { 6196 for (k = 0; k < nr_node_ids; k++) { 6197 int distance = node_distance(i, k); 6198 6199 if (distance > curr_distance && 6200 (distance < next_distance || 6201 next_distance == curr_distance)) 6202 next_distance = distance; 6203 6204 /* 6205 * While not a strong assumption it would be nice to know 6206 * about cases where if node A is connected to B, B is not 6207 * equally connected to A. 6208 */ 6209 if (sched_debug() && node_distance(k, i) != distance) 6210 sched_numa_warn("Node-distance not symmetric"); 6211 6212 if (sched_debug() && i && !find_numa_distance(distance)) 6213 sched_numa_warn("Node-0 not representative"); 6214 } 6215 if (next_distance != curr_distance) { 6216 sched_domains_numa_distance[level++] = next_distance; 6217 sched_domains_numa_levels = level; 6218 curr_distance = next_distance; 6219 } else break; 6220 } 6221 6222 /* 6223 * In case of sched_debug() we verify the above assumption. 6224 */ 6225 if (!sched_debug()) 6226 break; 6227 } 6228 /* 6229 * 'level' contains the number of unique distances, excluding the 6230 * identity distance node_distance(i,i). 6231 * 6232 * The sched_domains_numa_distance[] array includes the actual distance 6233 * numbers. 6234 */ 6235 6236 /* 6237 * Here, we should temporarily reset sched_domains_numa_levels to 0. 6238 * If it fails to allocate memory for array sched_domains_numa_masks[][], 6239 * the array will contain less then 'level' members. This could be 6240 * dangerous when we use it to iterate array sched_domains_numa_masks[][] 6241 * in other functions. 6242 * 6243 * We reset it to 'level' at the end of this function. 6244 */ 6245 sched_domains_numa_levels = 0; 6246 6247 sched_domains_numa_masks = kzalloc(sizeof(void *) * level, GFP_KERNEL); 6248 if (!sched_domains_numa_masks) 6249 return; 6250 6251 /* 6252 * Now for each level, construct a mask per node which contains all 6253 * cpus of nodes that are that many hops away from us. 6254 */ 6255 for (i = 0; i < level; i++) { 6256 sched_domains_numa_masks[i] = 6257 kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL); 6258 if (!sched_domains_numa_masks[i]) 6259 return; 6260 6261 for (j = 0; j < nr_node_ids; j++) { 6262 struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL); 6263 if (!mask) 6264 return; 6265 6266 sched_domains_numa_masks[i][j] = mask; 6267 6268 for (k = 0; k < nr_node_ids; k++) { 6269 if (node_distance(j, k) > sched_domains_numa_distance[i]) 6270 continue; 6271 6272 cpumask_or(mask, mask, cpumask_of_node(k)); 6273 } 6274 } 6275 } 6276 6277 /* Compute default topology size */ 6278 for (i = 0; sched_domain_topology[i].mask; i++); 6279 6280 tl = kzalloc((i + level + 1) * 6281 sizeof(struct sched_domain_topology_level), GFP_KERNEL); 6282 if (!tl) 6283 return; 6284 6285 /* 6286 * Copy the default topology bits.. 6287 */ 6288 for (i = 0; sched_domain_topology[i].mask; i++) 6289 tl[i] = sched_domain_topology[i]; 6290 6291 /* 6292 * .. and append 'j' levels of NUMA goodness. 6293 */ 6294 for (j = 0; j < level; i++, j++) { 6295 tl[i] = (struct sched_domain_topology_level){ 6296 .mask = sd_numa_mask, 6297 .sd_flags = cpu_numa_flags, 6298 .flags = SDTL_OVERLAP, 6299 .numa_level = j, 6300 SD_INIT_NAME(NUMA) 6301 }; 6302 } 6303 6304 sched_domain_topology = tl; 6305 6306 sched_domains_numa_levels = level; 6307} 6308 6309static void sched_domains_numa_masks_set(int cpu) 6310{ 6311 int i, j; 6312 int node = cpu_to_node(cpu); 6313 6314 for (i = 0; i < sched_domains_numa_levels; i++) { 6315 for (j = 0; j < nr_node_ids; j++) { 6316 if (node_distance(j, node) <= sched_domains_numa_distance[i]) 6317 cpumask_set_cpu(cpu, sched_domains_numa_masks[i][j]); 6318 } 6319 } 6320} 6321 6322static void sched_domains_numa_masks_clear(int cpu) 6323{ 6324 int i, j; 6325 for (i = 0; i < sched_domains_numa_levels; i++) { 6326 for (j = 0; j < nr_node_ids; j++) 6327 cpumask_clear_cpu(cpu, sched_domains_numa_masks[i][j]); 6328 } 6329} 6330 6331/* 6332 * Update sched_domains_numa_masks[level][node] array when new cpus 6333 * are onlined. 6334 */ 6335static int sched_domains_numa_masks_update(struct notifier_block *nfb, 6336 unsigned long action, 6337 void *hcpu) 6338{ 6339 int cpu = (long)hcpu; 6340 6341 switch (action & ~CPU_TASKS_FROZEN) { 6342 case CPU_ONLINE: 6343 sched_domains_numa_masks_set(cpu); 6344 break; 6345 6346 case CPU_DEAD: 6347 sched_domains_numa_masks_clear(cpu); 6348 break; 6349 6350 default: 6351 return NOTIFY_DONE; 6352 } 6353 6354 return NOTIFY_OK; 6355} 6356#else 6357static inline void sched_init_numa(void) 6358{ 6359} 6360 6361static int sched_domains_numa_masks_update(struct notifier_block *nfb, 6362 unsigned long action, 6363 void *hcpu) 6364{ 6365 return 0; 6366} 6367#endif /* CONFIG_NUMA */ 6368 6369static int __sdt_alloc(const struct cpumask *cpu_map) 6370{ 6371 struct sched_domain_topology_level *tl; 6372 int j; 6373 6374 for_each_sd_topology(tl) { 6375 struct sd_data *sdd = &tl->data; 6376 6377 sdd->sd = alloc_percpu(struct sched_domain *); 6378 if (!sdd->sd) 6379 return -ENOMEM; 6380 6381 sdd->sg = alloc_percpu(struct sched_group *); 6382 if (!sdd->sg) 6383 return -ENOMEM; 6384 6385 sdd->sgc = alloc_percpu(struct sched_group_capacity *); 6386 if (!sdd->sgc) 6387 return -ENOMEM; 6388 6389 for_each_cpu(j, cpu_map) { 6390 struct sched_domain *sd; 6391 struct sched_group *sg; 6392 struct sched_group_capacity *sgc; 6393 6394 sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(), 6395 GFP_KERNEL, cpu_to_node(j)); 6396 if (!sd) 6397 return -ENOMEM; 6398 6399 *per_cpu_ptr(sdd->sd, j) = sd; 6400 6401 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), 6402 GFP_KERNEL, cpu_to_node(j)); 6403 if (!sg) 6404 return -ENOMEM; 6405 6406 sg->next = sg; 6407 6408 *per_cpu_ptr(sdd->sg, j) = sg; 6409 6410 sgc = kzalloc_node(sizeof(struct sched_group_capacity) + cpumask_size(), 6411 GFP_KERNEL, cpu_to_node(j)); 6412 if (!sgc) 6413 return -ENOMEM; 6414 6415 *per_cpu_ptr(sdd->sgc, j) = sgc; 6416 } 6417 } 6418 6419 return 0; 6420} 6421 6422static void __sdt_free(const struct cpumask *cpu_map) 6423{ 6424 struct sched_domain_topology_level *tl; 6425 int j; 6426 6427 for_each_sd_topology(tl) { 6428 struct sd_data *sdd = &tl->data; 6429 6430 for_each_cpu(j, cpu_map) { 6431 struct sched_domain *sd; 6432 6433 if (sdd->sd) { 6434 sd = *per_cpu_ptr(sdd->sd, j); 6435 if (sd && (sd->flags & SD_OVERLAP)) 6436 free_sched_groups(sd->groups, 0); 6437 kfree(*per_cpu_ptr(sdd->sd, j)); 6438 } 6439 6440 if (sdd->sg) 6441 kfree(*per_cpu_ptr(sdd->sg, j)); 6442 if (sdd->sgc) 6443 kfree(*per_cpu_ptr(sdd->sgc, j)); 6444 } 6445 free_percpu(sdd->sd); 6446 sdd->sd = NULL; 6447 free_percpu(sdd->sg); 6448 sdd->sg = NULL; 6449 free_percpu(sdd->sgc); 6450 sdd->sgc = NULL; 6451 } 6452} 6453 6454struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl, 6455 const struct cpumask *cpu_map, struct sched_domain_attr *attr, 6456 struct sched_domain *child, int cpu) 6457{ 6458 struct sched_domain *sd = sd_init(tl, cpu); 6459 if (!sd) 6460 return child; 6461 6462 cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu)); 6463 if (child) { 6464 sd->level = child->level + 1; 6465 sched_domain_level_max = max(sched_domain_level_max, sd->level); 6466 child->parent = sd; 6467 sd->child = child; 6468 } 6469 set_domain_attribute(sd, attr); 6470 6471 return sd; 6472} 6473 6474/* 6475 * Build sched domains for a given set of cpus and attach the sched domains 6476 * to the individual cpus 6477 */ 6478static int build_sched_domains(const struct cpumask *cpu_map, 6479 struct sched_domain_attr *attr) 6480{ 6481 enum s_alloc alloc_state; 6482 struct sched_domain *sd; 6483 struct s_data d; 6484 int i, ret = -ENOMEM; 6485 6486 alloc_state = __visit_domain_allocation_hell(&d, cpu_map); 6487 if (alloc_state != sa_rootdomain) 6488 goto error; 6489 6490 /* Set up domains for cpus specified by the cpu_map. */ 6491 for_each_cpu(i, cpu_map) { 6492 struct sched_domain_topology_level *tl; 6493 6494 sd = NULL; 6495 for_each_sd_topology(tl) { 6496 sd = build_sched_domain(tl, cpu_map, attr, sd, i); 6497 if (tl == sched_domain_topology) 6498 *per_cpu_ptr(d.sd, i) = sd; 6499 if (tl->flags & SDTL_OVERLAP || sched_feat(FORCE_SD_OVERLAP)) 6500 sd->flags |= SD_OVERLAP; 6501 if (cpumask_equal(cpu_map, sched_domain_span(sd))) 6502 break; 6503 } 6504 } 6505 6506 /* Build the groups for the domains */ 6507 for_each_cpu(i, cpu_map) { 6508 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { 6509 sd->span_weight = cpumask_weight(sched_domain_span(sd)); 6510 if (sd->flags & SD_OVERLAP) { 6511 if (build_overlap_sched_groups(sd, i)) 6512 goto error; 6513 } else { 6514 if (build_sched_groups(sd, i)) 6515 goto error; 6516 } 6517 } 6518 } 6519 6520 /* Calculate CPU capacity for physical packages and nodes */ 6521 for (i = nr_cpumask_bits-1; i >= 0; i--) { 6522 if (!cpumask_test_cpu(i, cpu_map)) 6523 continue; 6524 6525 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { 6526 claim_allocations(i, sd); 6527 init_sched_groups_capacity(i, sd); 6528 } 6529 } 6530 6531 /* Attach the domains */ 6532 rcu_read_lock(); 6533 for_each_cpu(i, cpu_map) { 6534 sd = *per_cpu_ptr(d.sd, i); 6535 cpu_attach_domain(sd, d.rd, i); 6536 } 6537 rcu_read_unlock(); 6538 6539 ret = 0; 6540error: 6541 __free_domain_allocs(&d, alloc_state, cpu_map); 6542 return ret; 6543} 6544 6545static cpumask_var_t *doms_cur; /* current sched domains */ 6546static int ndoms_cur; /* number of sched domains in 'doms_cur' */ 6547static struct sched_domain_attr *dattr_cur; 6548 /* attribues of custom domains in 'doms_cur' */ 6549 6550/* 6551 * Special case: If a kmalloc of a doms_cur partition (array of 6552 * cpumask) fails, then fallback to a single sched domain, 6553 * as determined by the single cpumask fallback_doms. 6554 */ 6555static cpumask_var_t fallback_doms; 6556 6557/* 6558 * arch_update_cpu_topology lets virtualized architectures update the 6559 * cpu core maps. It is supposed to return 1 if the topology changed 6560 * or 0 if it stayed the same. 6561 */ 6562int __weak arch_update_cpu_topology(void) 6563{ 6564 return 0; 6565} 6566 6567cpumask_var_t *alloc_sched_domains(unsigned int ndoms) 6568{ 6569 int i; 6570 cpumask_var_t *doms; 6571 6572 doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL); 6573 if (!doms) 6574 return NULL; 6575 for (i = 0; i < ndoms; i++) { 6576 if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) { 6577 free_sched_domains(doms, i); 6578 return NULL; 6579 } 6580 } 6581 return doms; 6582} 6583 6584void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms) 6585{ 6586 unsigned int i; 6587 for (i = 0; i < ndoms; i++) 6588 free_cpumask_var(doms[i]); 6589 kfree(doms); 6590} 6591 6592/* 6593 * Set up scheduler domains and groups. Callers must hold the hotplug lock. 6594 * For now this just excludes isolated cpus, but could be used to 6595 * exclude other special cases in the future. 6596 */ 6597static int init_sched_domains(const struct cpumask *cpu_map) 6598{ 6599 int err; 6600 6601 arch_update_cpu_topology(); 6602 ndoms_cur = 1; 6603 doms_cur = alloc_sched_domains(ndoms_cur); 6604 if (!doms_cur) 6605 doms_cur = &fallback_doms; 6606 cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map); 6607 err = build_sched_domains(doms_cur[0], NULL); 6608 register_sched_domain_sysctl(); 6609 6610 return err; 6611} 6612 6613/* 6614 * Detach sched domains from a group of cpus specified in cpu_map 6615 * These cpus will now be attached to the NULL domain 6616 */ 6617static void detach_destroy_domains(const struct cpumask *cpu_map) 6618{ 6619 int i; 6620 6621 rcu_read_lock(); 6622 for_each_cpu(i, cpu_map) 6623 cpu_attach_domain(NULL, &def_root_domain, i); 6624 rcu_read_unlock(); 6625} 6626 6627/* handle null as "default" */ 6628static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur, 6629 struct sched_domain_attr *new, int idx_new) 6630{ 6631 struct sched_domain_attr tmp; 6632 6633 /* fast path */ 6634 if (!new && !cur) 6635 return 1; 6636 6637 tmp = SD_ATTR_INIT; 6638 return !memcmp(cur ? (cur + idx_cur) : &tmp, 6639 new ? (new + idx_new) : &tmp, 6640 sizeof(struct sched_domain_attr)); 6641} 6642 6643/* 6644 * Partition sched domains as specified by the 'ndoms_new' 6645 * cpumasks in the array doms_new[] of cpumasks. This compares 6646 * doms_new[] to the current sched domain partitioning, doms_cur[]. 6647 * It destroys each deleted domain and builds each new domain. 6648 * 6649 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'. 6650 * The masks don't intersect (don't overlap.) We should setup one 6651 * sched domain for each mask. CPUs not in any of the cpumasks will 6652 * not be load balanced. If the same cpumask appears both in the 6653 * current 'doms_cur' domains and in the new 'doms_new', we can leave 6654 * it as it is. 6655 * 6656 * The passed in 'doms_new' should be allocated using 6657 * alloc_sched_domains. This routine takes ownership of it and will 6658 * free_sched_domains it when done with it. If the caller failed the 6659 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1, 6660 * and partition_sched_domains() will fallback to the single partition 6661 * 'fallback_doms', it also forces the domains to be rebuilt. 6662 * 6663 * If doms_new == NULL it will be replaced with cpu_online_mask. 6664 * ndoms_new == 0 is a special case for destroying existing domains, 6665 * and it will not create the default domain. 6666 * 6667 * Call with hotplug lock held 6668 */ 6669void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[], 6670 struct sched_domain_attr *dattr_new) 6671{ 6672 int i, j, n; 6673 int new_topology; 6674 6675 mutex_lock(&sched_domains_mutex); 6676 6677 /* always unregister in case we don't destroy any domains */ 6678 unregister_sched_domain_sysctl(); 6679 6680 /* Let architecture update cpu core mappings. */ 6681 new_topology = arch_update_cpu_topology(); 6682 6683 n = doms_new ? ndoms_new : 0; 6684 6685 /* Destroy deleted domains */ 6686 for (i = 0; i < ndoms_cur; i++) { 6687 for (j = 0; j < n && !new_topology; j++) { 6688 if (cpumask_equal(doms_cur[i], doms_new[j]) 6689 && dattrs_equal(dattr_cur, i, dattr_new, j)) 6690 goto match1; 6691 } 6692 /* no match - a current sched domain not in new doms_new[] */ 6693 detach_destroy_domains(doms_cur[i]); 6694match1: 6695 ; 6696 } 6697 6698 n = ndoms_cur; 6699 if (doms_new == NULL) { 6700 n = 0; 6701 doms_new = &fallback_doms; 6702 cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map); 6703 WARN_ON_ONCE(dattr_new); 6704 } 6705 6706 /* Build new domains */ 6707 for (i = 0; i < ndoms_new; i++) { 6708 for (j = 0; j < n && !new_topology; j++) { 6709 if (cpumask_equal(doms_new[i], doms_cur[j]) 6710 && dattrs_equal(dattr_new, i, dattr_cur, j)) 6711 goto match2; 6712 } 6713 /* no match - add a new doms_new */ 6714 build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL); 6715match2: 6716 ; 6717 } 6718 6719 /* Remember the new sched domains */ 6720 if (doms_cur != &fallback_doms) 6721 free_sched_domains(doms_cur, ndoms_cur); 6722 kfree(dattr_cur); /* kfree(NULL) is safe */ 6723 doms_cur = doms_new; 6724 dattr_cur = dattr_new; 6725 ndoms_cur = ndoms_new; 6726 6727 register_sched_domain_sysctl(); 6728 6729 mutex_unlock(&sched_domains_mutex); 6730} 6731 6732static int num_cpus_frozen; /* used to mark begin/end of suspend/resume */ 6733 6734/* 6735 * Update cpusets according to cpu_active mask. If cpusets are 6736 * disabled, cpuset_update_active_cpus() becomes a simple wrapper 6737 * around partition_sched_domains(). 6738 * 6739 * If we come here as part of a suspend/resume, don't touch cpusets because we 6740 * want to restore it back to its original state upon resume anyway. 6741 */ 6742static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action, 6743 void *hcpu) 6744{ 6745 switch (action) { 6746 case CPU_ONLINE_FROZEN: 6747 case CPU_DOWN_FAILED_FROZEN: 6748 6749 /* 6750 * num_cpus_frozen tracks how many CPUs are involved in suspend 6751 * resume sequence. As long as this is not the last online 6752 * operation in the resume sequence, just build a single sched 6753 * domain, ignoring cpusets. 6754 */ 6755 num_cpus_frozen--; 6756 if (likely(num_cpus_frozen)) { 6757 partition_sched_domains(1, NULL, NULL); 6758 break; 6759 } 6760 6761 /* 6762 * This is the last CPU online operation. So fall through and 6763 * restore the original sched domains by considering the 6764 * cpuset configurations. 6765 */ 6766 6767 case CPU_ONLINE: 6768 case CPU_DOWN_FAILED: 6769 cpuset_update_active_cpus(true); 6770 break; 6771 default: 6772 return NOTIFY_DONE; 6773 } 6774 return NOTIFY_OK; 6775} 6776 6777static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action, 6778 void *hcpu) 6779{ 6780 switch (action) { 6781 case CPU_DOWN_PREPARE: 6782 cpuset_update_active_cpus(false); 6783 break; 6784 case CPU_DOWN_PREPARE_FROZEN: 6785 num_cpus_frozen++; 6786 partition_sched_domains(1, NULL, NULL); 6787 break; 6788 default: 6789 return NOTIFY_DONE; 6790 } 6791 return NOTIFY_OK; 6792} 6793 6794void __init sched_init_smp(void) 6795{ 6796 cpumask_var_t non_isolated_cpus; 6797 6798 alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL); 6799 alloc_cpumask_var(&fallback_doms, GFP_KERNEL); 6800 6801 sched_init_numa(); 6802 6803 /* 6804 * There's no userspace yet to cause hotplug operations; hence all the 6805 * cpu masks are stable and all blatant races in the below code cannot 6806 * happen. 6807 */ 6808 mutex_lock(&sched_domains_mutex); 6809 init_sched_domains(cpu_active_mask); 6810 cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map); 6811 if (cpumask_empty(non_isolated_cpus)) 6812 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus); 6813 mutex_unlock(&sched_domains_mutex); 6814 6815 hotcpu_notifier(sched_domains_numa_masks_update, CPU_PRI_SCHED_ACTIVE); 6816 hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE); 6817 hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE); 6818 6819 init_hrtick(); 6820 6821 /* Move init over to a non-isolated CPU */ 6822 if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0) 6823 BUG(); 6824 sched_init_granularity(); 6825 free_cpumask_var(non_isolated_cpus); 6826 6827 init_sched_rt_class(); 6828 init_sched_dl_class(); 6829} 6830#else 6831void __init sched_init_smp(void) 6832{ 6833 sched_init_granularity(); 6834} 6835#endif /* CONFIG_SMP */ 6836 6837const_debug unsigned int sysctl_timer_migration = 1; 6838 6839int in_sched_functions(unsigned long addr) 6840{ 6841 return in_lock_functions(addr) || 6842 (addr >= (unsigned long)__sched_text_start 6843 && addr < (unsigned long)__sched_text_end); 6844} 6845 6846#ifdef CONFIG_CGROUP_SCHED 6847/* 6848 * Default task group. 6849 * Every task in system belongs to this group at bootup. 6850 */ 6851struct task_group root_task_group; 6852LIST_HEAD(task_groups); 6853#endif 6854 6855DECLARE_PER_CPU(cpumask_var_t, load_balance_mask); 6856 6857void __init sched_init(void) 6858{ 6859 int i, j; 6860 unsigned long alloc_size = 0, ptr; 6861 6862#ifdef CONFIG_FAIR_GROUP_SCHED 6863 alloc_size += 2 * nr_cpu_ids * sizeof(void **); 6864#endif 6865#ifdef CONFIG_RT_GROUP_SCHED 6866 alloc_size += 2 * nr_cpu_ids * sizeof(void **); 6867#endif 6868#ifdef CONFIG_CPUMASK_OFFSTACK 6869 alloc_size += num_possible_cpus() * cpumask_size(); 6870#endif 6871 if (alloc_size) { 6872 ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT); 6873 6874#ifdef CONFIG_FAIR_GROUP_SCHED 6875 root_task_group.se = (struct sched_entity **)ptr; 6876 ptr += nr_cpu_ids * sizeof(void **); 6877 6878 root_task_group.cfs_rq = (struct cfs_rq **)ptr; 6879 ptr += nr_cpu_ids * sizeof(void **); 6880 6881#endif /* CONFIG_FAIR_GROUP_SCHED */ 6882#ifdef CONFIG_RT_GROUP_SCHED 6883 root_task_group.rt_se = (struct sched_rt_entity **)ptr; 6884 ptr += nr_cpu_ids * sizeof(void **); 6885 6886 root_task_group.rt_rq = (struct rt_rq **)ptr; 6887 ptr += nr_cpu_ids * sizeof(void **); 6888 6889#endif /* CONFIG_RT_GROUP_SCHED */ 6890#ifdef CONFIG_CPUMASK_OFFSTACK 6891 for_each_possible_cpu(i) { 6892 per_cpu(load_balance_mask, i) = (void *)ptr; 6893 ptr += cpumask_size(); 6894 } 6895#endif /* CONFIG_CPUMASK_OFFSTACK */ 6896 } 6897 6898 init_rt_bandwidth(&def_rt_bandwidth, 6899 global_rt_period(), global_rt_runtime()); 6900 init_dl_bandwidth(&def_dl_bandwidth, 6901 global_rt_period(), global_rt_runtime()); 6902 6903#ifdef CONFIG_SMP 6904 init_defrootdomain(); 6905#endif 6906 6907#ifdef CONFIG_RT_GROUP_SCHED 6908 init_rt_bandwidth(&root_task_group.rt_bandwidth, 6909 global_rt_period(), global_rt_runtime()); 6910#endif /* CONFIG_RT_GROUP_SCHED */ 6911 6912#ifdef CONFIG_CGROUP_SCHED 6913 list_add(&root_task_group.list, &task_groups); 6914 INIT_LIST_HEAD(&root_task_group.children); 6915 INIT_LIST_HEAD(&root_task_group.siblings); 6916 autogroup_init(&init_task); 6917 6918#endif /* CONFIG_CGROUP_SCHED */ 6919 6920 for_each_possible_cpu(i) { 6921 struct rq *rq; 6922 6923 rq = cpu_rq(i); 6924 raw_spin_lock_init(&rq->lock); 6925 rq->nr_running = 0; 6926 rq->calc_load_active = 0; 6927 rq->calc_load_update = jiffies + LOAD_FREQ; 6928 init_cfs_rq(&rq->cfs); 6929 init_rt_rq(&rq->rt, rq); 6930 init_dl_rq(&rq->dl, rq); 6931#ifdef CONFIG_FAIR_GROUP_SCHED 6932 root_task_group.shares = ROOT_TASK_GROUP_LOAD; 6933 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list); 6934 /* 6935 * How much cpu bandwidth does root_task_group get? 6936 * 6937 * In case of task-groups formed thr' the cgroup filesystem, it 6938 * gets 100% of the cpu resources in the system. This overall 6939 * system cpu resource is divided among the tasks of 6940 * root_task_group and its child task-groups in a fair manner, 6941 * based on each entity's (task or task-group's) weight 6942 * (se->load.weight). 6943 * 6944 * In other words, if root_task_group has 10 tasks of weight 6945 * 1024) and two child groups A0 and A1 (of weight 1024 each), 6946 * then A0's share of the cpu resource is: 6947 * 6948 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33% 6949 * 6950 * We achieve this by letting root_task_group's tasks sit 6951 * directly in rq->cfs (i.e root_task_group->se[] = NULL). 6952 */ 6953 init_cfs_bandwidth(&root_task_group.cfs_bandwidth); 6954 init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL); 6955#endif /* CONFIG_FAIR_GROUP_SCHED */ 6956 6957 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime; 6958#ifdef CONFIG_RT_GROUP_SCHED 6959 init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL); 6960#endif 6961 6962 for (j = 0; j < CPU_LOAD_IDX_MAX; j++) 6963 rq->cpu_load[j] = 0; 6964 6965 rq->last_load_update_tick = jiffies; 6966 6967#ifdef CONFIG_SMP 6968 rq->sd = NULL; 6969 rq->rd = NULL; 6970 rq->cpu_capacity = SCHED_CAPACITY_SCALE; 6971 rq->post_schedule = 0; 6972 rq->active_balance = 0; 6973 rq->next_balance = jiffies; 6974 rq->push_cpu = 0; 6975 rq->cpu = i; 6976 rq->online = 0; 6977 rq->idle_stamp = 0; 6978 rq->avg_idle = 2*sysctl_sched_migration_cost; 6979 rq->max_idle_balance_cost = sysctl_sched_migration_cost; 6980 6981 INIT_LIST_HEAD(&rq->cfs_tasks); 6982 6983 rq_attach_root(rq, &def_root_domain); 6984#ifdef CONFIG_NO_HZ_COMMON 6985 rq->nohz_flags = 0; 6986#endif 6987#ifdef CONFIG_NO_HZ_FULL 6988 rq->last_sched_tick = 0; 6989#endif 6990#endif 6991 init_rq_hrtick(rq); 6992 atomic_set(&rq->nr_iowait, 0); 6993 } 6994 6995 set_load_weight(&init_task); 6996 6997#ifdef CONFIG_PREEMPT_NOTIFIERS 6998 INIT_HLIST_HEAD(&init_task.preempt_notifiers); 6999#endif 7000 7001 /* 7002 * The boot idle thread does lazy MMU switching as well: 7003 */ 7004 atomic_inc(&init_mm.mm_count); 7005 enter_lazy_tlb(&init_mm, current); 7006 7007 /* 7008 * Make us the idle thread. Technically, schedule() should not be 7009 * called from this thread, however somewhere below it might be, 7010 * but because we are the idle thread, we just pick up running again 7011 * when this runqueue becomes "idle". 7012 */ 7013 init_idle(current, smp_processor_id()); 7014 7015 calc_load_update = jiffies + LOAD_FREQ; 7016 7017 /* 7018 * During early bootup we pretend to be a normal task: 7019 */ 7020 current->sched_class = &fair_sched_class; 7021 7022#ifdef CONFIG_SMP 7023 zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT); 7024 /* May be allocated at isolcpus cmdline parse time */ 7025 if (cpu_isolated_map == NULL) 7026 zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT); 7027 idle_thread_set_boot_cpu(); 7028 set_cpu_rq_start_time(); 7029#endif 7030 init_sched_fair_class(); 7031 7032 scheduler_running = 1; 7033} 7034 7035#ifdef CONFIG_DEBUG_ATOMIC_SLEEP 7036static inline int preempt_count_equals(int preempt_offset) 7037{ 7038 int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth(); 7039 7040 return (nested == preempt_offset); 7041} 7042 7043void __might_sleep(const char *file, int line, int preempt_offset) 7044{ 7045 static unsigned long prev_jiffy; /* ratelimiting */ 7046 7047 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */ 7048 if ((preempt_count_equals(preempt_offset) && !irqs_disabled() && 7049 !is_idle_task(current)) || 7050 system_state != SYSTEM_RUNNING || oops_in_progress) 7051 return; 7052 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) 7053 return; 7054 prev_jiffy = jiffies; 7055 7056 printk(KERN_ERR 7057 "BUG: sleeping function called from invalid context at %s:%d\n", 7058 file, line); 7059 printk(KERN_ERR 7060 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n", 7061 in_atomic(), irqs_disabled(), 7062 current->pid, current->comm); 7063 7064 debug_show_held_locks(current); 7065 if (irqs_disabled()) 7066 print_irqtrace_events(current); 7067#ifdef CONFIG_DEBUG_PREEMPT 7068 if (!preempt_count_equals(preempt_offset)) { 7069 pr_err("Preemption disabled at:"); 7070 print_ip_sym(current->preempt_disable_ip); 7071 pr_cont("\n"); 7072 } 7073#endif 7074 dump_stack(); 7075} 7076EXPORT_SYMBOL(__might_sleep); 7077#endif 7078 7079#ifdef CONFIG_MAGIC_SYSRQ 7080static void normalize_task(struct rq *rq, struct task_struct *p) 7081{ 7082 const struct sched_class *prev_class = p->sched_class; 7083 struct sched_attr attr = { 7084 .sched_policy = SCHED_NORMAL, 7085 }; 7086 int old_prio = p->prio; 7087 int on_rq; 7088 7089 on_rq = p->on_rq; 7090 if (on_rq) 7091 dequeue_task(rq, p, 0); 7092 __setscheduler(rq, p, &attr); 7093 if (on_rq) { 7094 enqueue_task(rq, p, 0); 7095 resched_task(rq->curr); 7096 } 7097 7098 check_class_changed(rq, p, prev_class, old_prio); 7099} 7100 7101void normalize_rt_tasks(void) 7102{ 7103 struct task_struct *g, *p; 7104 unsigned long flags; 7105 struct rq *rq; 7106 7107 read_lock_irqsave(&tasklist_lock, flags); 7108 do_each_thread(g, p) { 7109 /* 7110 * Only normalize user tasks: 7111 */ 7112 if (!p->mm) 7113 continue; 7114 7115 p->se.exec_start = 0; 7116#ifdef CONFIG_SCHEDSTATS 7117 p->se.statistics.wait_start = 0; 7118 p->se.statistics.sleep_start = 0; 7119 p->se.statistics.block_start = 0; 7120#endif 7121 7122 if (!dl_task(p) && !rt_task(p)) { 7123 /* 7124 * Renice negative nice level userspace 7125 * tasks back to 0: 7126 */ 7127 if (task_nice(p) < 0 && p->mm) 7128 set_user_nice(p, 0); 7129 continue; 7130 } 7131 7132 raw_spin_lock(&p->pi_lock); 7133 rq = __task_rq_lock(p); 7134 7135 normalize_task(rq, p); 7136 7137 __task_rq_unlock(rq); 7138 raw_spin_unlock(&p->pi_lock); 7139 } while_each_thread(g, p); 7140 7141 read_unlock_irqrestore(&tasklist_lock, flags); 7142} 7143 7144#endif /* CONFIG_MAGIC_SYSRQ */ 7145 7146#if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) 7147/* 7148 * These functions are only useful for the IA64 MCA handling, or kdb. 7149 * 7150 * They can only be called when the whole system has been 7151 * stopped - every CPU needs to be quiescent, and no scheduling 7152 * activity can take place. Using them for anything else would 7153 * be a serious bug, and as a result, they aren't even visible 7154 * under any other configuration. 7155 */ 7156 7157/** 7158 * curr_task - return the current task for a given cpu. 7159 * @cpu: the processor in question. 7160 * 7161 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! 7162 * 7163 * Return: The current task for @cpu. 7164 */ 7165struct task_struct *curr_task(int cpu) 7166{ 7167 return cpu_curr(cpu); 7168} 7169 7170#endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */ 7171 7172#ifdef CONFIG_IA64 7173/** 7174 * set_curr_task - set the current task for a given cpu. 7175 * @cpu: the processor in question. 7176 * @p: the task pointer to set. 7177 * 7178 * Description: This function must only be used when non-maskable interrupts 7179 * are serviced on a separate stack. It allows the architecture to switch the 7180 * notion of the current task on a cpu in a non-blocking manner. This function 7181 * must be called with all CPU's synchronized, and interrupts disabled, the 7182 * and caller must save the original value of the current task (see 7183 * curr_task() above) and restore that value before reenabling interrupts and 7184 * re-starting the system. 7185 * 7186 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! 7187 */ 7188void set_curr_task(int cpu, struct task_struct *p) 7189{ 7190 cpu_curr(cpu) = p; 7191} 7192 7193#endif 7194 7195#ifdef CONFIG_CGROUP_SCHED 7196/* task_group_lock serializes the addition/removal of task groups */ 7197static DEFINE_SPINLOCK(task_group_lock); 7198 7199static void free_sched_group(struct task_group *tg) 7200{ 7201 free_fair_sched_group(tg); 7202 free_rt_sched_group(tg); 7203 autogroup_free(tg); 7204 kfree(tg); 7205} 7206 7207/* allocate runqueue etc for a new task group */ 7208struct task_group *sched_create_group(struct task_group *parent) 7209{ 7210 struct task_group *tg; 7211 7212 tg = kzalloc(sizeof(*tg), GFP_KERNEL); 7213 if (!tg) 7214 return ERR_PTR(-ENOMEM); 7215 7216 if (!alloc_fair_sched_group(tg, parent)) 7217 goto err; 7218 7219 if (!alloc_rt_sched_group(tg, parent)) 7220 goto err; 7221 7222 return tg; 7223 7224err: 7225 free_sched_group(tg); 7226 return ERR_PTR(-ENOMEM); 7227} 7228 7229void sched_online_group(struct task_group *tg, struct task_group *parent) 7230{ 7231 unsigned long flags; 7232 7233 spin_lock_irqsave(&task_group_lock, flags); 7234 list_add_rcu(&tg->list, &task_groups); 7235 7236 WARN_ON(!parent); /* root should already exist */ 7237 7238 tg->parent = parent; 7239 INIT_LIST_HEAD(&tg->children); 7240 list_add_rcu(&tg->siblings, &parent->children); 7241 spin_unlock_irqrestore(&task_group_lock, flags); 7242} 7243 7244/* rcu callback to free various structures associated with a task group */ 7245static void free_sched_group_rcu(struct rcu_head *rhp) 7246{ 7247 /* now it should be safe to free those cfs_rqs */ 7248 free_sched_group(container_of(rhp, struct task_group, rcu)); 7249} 7250 7251/* Destroy runqueue etc associated with a task group */ 7252void sched_destroy_group(struct task_group *tg) 7253{ 7254 /* wait for possible concurrent references to cfs_rqs complete */ 7255 call_rcu(&tg->rcu, free_sched_group_rcu); 7256} 7257 7258void sched_offline_group(struct task_group *tg) 7259{ 7260 unsigned long flags; 7261 int i; 7262 7263 /* end participation in shares distribution */ 7264 for_each_possible_cpu(i) 7265 unregister_fair_sched_group(tg, i); 7266 7267 spin_lock_irqsave(&task_group_lock, flags); 7268 list_del_rcu(&tg->list); 7269 list_del_rcu(&tg->siblings); 7270 spin_unlock_irqrestore(&task_group_lock, flags); 7271} 7272 7273/* change task's runqueue when it moves between groups. 7274 * The caller of this function should have put the task in its new group 7275 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to 7276 * reflect its new group. 7277 */ 7278void sched_move_task(struct task_struct *tsk) 7279{ 7280 struct task_group *tg; 7281 int on_rq, running; 7282 unsigned long flags; 7283 struct rq *rq; 7284 7285 rq = task_rq_lock(tsk, &flags); 7286 7287 running = task_current(rq, tsk); 7288 on_rq = tsk->on_rq; 7289 7290 if (on_rq) 7291 dequeue_task(rq, tsk, 0); 7292 if (unlikely(running)) 7293 tsk->sched_class->put_prev_task(rq, tsk); 7294 7295 tg = container_of(task_css_check(tsk, cpu_cgrp_id, 7296 lockdep_is_held(&tsk->sighand->siglock)), 7297 struct task_group, css); 7298 tg = autogroup_task_group(tsk, tg); 7299 tsk->sched_task_group = tg; 7300 7301#ifdef CONFIG_FAIR_GROUP_SCHED 7302 if (tsk->sched_class->task_move_group) 7303 tsk->sched_class->task_move_group(tsk, on_rq); 7304 else 7305#endif 7306 set_task_rq(tsk, task_cpu(tsk)); 7307 7308 if (unlikely(running)) 7309 tsk->sched_class->set_curr_task(rq); 7310 if (on_rq) 7311 enqueue_task(rq, tsk, 0); 7312 7313 task_rq_unlock(rq, tsk, &flags); 7314} 7315#endif /* CONFIG_CGROUP_SCHED */ 7316 7317#ifdef CONFIG_RT_GROUP_SCHED 7318/* 7319 * Ensure that the real time constraints are schedulable. 7320 */ 7321static DEFINE_MUTEX(rt_constraints_mutex); 7322 7323/* Must be called with tasklist_lock held */ 7324static inline int tg_has_rt_tasks(struct task_group *tg) 7325{ 7326 struct task_struct *g, *p; 7327 7328 do_each_thread(g, p) { 7329 if (rt_task(p) && task_rq(p)->rt.tg == tg) 7330 return 1; 7331 } while_each_thread(g, p); 7332 7333 return 0; 7334} 7335 7336struct rt_schedulable_data { 7337 struct task_group *tg; 7338 u64 rt_period; 7339 u64 rt_runtime; 7340}; 7341 7342static int tg_rt_schedulable(struct task_group *tg, void *data) 7343{ 7344 struct rt_schedulable_data *d = data; 7345 struct task_group *child; 7346 unsigned long total, sum = 0; 7347 u64 period, runtime; 7348 7349 period = ktime_to_ns(tg->rt_bandwidth.rt_period); 7350 runtime = tg->rt_bandwidth.rt_runtime; 7351 7352 if (tg == d->tg) { 7353 period = d->rt_period; 7354 runtime = d->rt_runtime; 7355 } 7356 7357 /* 7358 * Cannot have more runtime than the period. 7359 */ 7360 if (runtime > period && runtime != RUNTIME_INF) 7361 return -EINVAL; 7362 7363 /* 7364 * Ensure we don't starve existing RT tasks. 7365 */ 7366 if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg)) 7367 return -EBUSY; 7368 7369 total = to_ratio(period, runtime); 7370 7371 /* 7372 * Nobody can have more than the global setting allows. 7373 */ 7374 if (total > to_ratio(global_rt_period(), global_rt_runtime())) 7375 return -EINVAL; 7376 7377 /* 7378 * The sum of our children's runtime should not exceed our own. 7379 */ 7380 list_for_each_entry_rcu(child, &tg->children, siblings) { 7381 period = ktime_to_ns(child->rt_bandwidth.rt_period); 7382 runtime = child->rt_bandwidth.rt_runtime; 7383 7384 if (child == d->tg) { 7385 period = d->rt_period; 7386 runtime = d->rt_runtime; 7387 } 7388 7389 sum += to_ratio(period, runtime); 7390 } 7391 7392 if (sum > total) 7393 return -EINVAL; 7394 7395 return 0; 7396} 7397 7398static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime) 7399{ 7400 int ret; 7401 7402 struct rt_schedulable_data data = { 7403 .tg = tg, 7404 .rt_period = period, 7405 .rt_runtime = runtime, 7406 }; 7407 7408 rcu_read_lock(); 7409 ret = walk_tg_tree(tg_rt_schedulable, tg_nop, &data); 7410 rcu_read_unlock(); 7411 7412 return ret; 7413} 7414 7415static int tg_set_rt_bandwidth(struct task_group *tg, 7416 u64 rt_period, u64 rt_runtime) 7417{ 7418 int i, err = 0; 7419 7420 mutex_lock(&rt_constraints_mutex); 7421 read_lock(&tasklist_lock); 7422 err = __rt_schedulable(tg, rt_period, rt_runtime); 7423 if (err) 7424 goto unlock; 7425 7426 raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock); 7427 tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period); 7428 tg->rt_bandwidth.rt_runtime = rt_runtime; 7429 7430 for_each_possible_cpu(i) { 7431 struct rt_rq *rt_rq = tg->rt_rq[i]; 7432 7433 raw_spin_lock(&rt_rq->rt_runtime_lock); 7434 rt_rq->rt_runtime = rt_runtime; 7435 raw_spin_unlock(&rt_rq->rt_runtime_lock); 7436 } 7437 raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock); 7438unlock: 7439 read_unlock(&tasklist_lock); 7440 mutex_unlock(&rt_constraints_mutex); 7441 7442 return err; 7443} 7444 7445static int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us) 7446{ 7447 u64 rt_runtime, rt_period; 7448 7449 rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period); 7450 rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC; 7451 if (rt_runtime_us < 0) 7452 rt_runtime = RUNTIME_INF; 7453 7454 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); 7455} 7456 7457static long sched_group_rt_runtime(struct task_group *tg) 7458{ 7459 u64 rt_runtime_us; 7460 7461 if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF) 7462 return -1; 7463 7464 rt_runtime_us = tg->rt_bandwidth.rt_runtime; 7465 do_div(rt_runtime_us, NSEC_PER_USEC); 7466 return rt_runtime_us; 7467} 7468 7469static int sched_group_set_rt_period(struct task_group *tg, long rt_period_us) 7470{ 7471 u64 rt_runtime, rt_period; 7472 7473 rt_period = (u64)rt_period_us * NSEC_PER_USEC; 7474 rt_runtime = tg->rt_bandwidth.rt_runtime; 7475 7476 if (rt_period == 0) 7477 return -EINVAL; 7478 7479 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); 7480} 7481 7482static long sched_group_rt_period(struct task_group *tg) 7483{ 7484 u64 rt_period_us; 7485 7486 rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period); 7487 do_div(rt_period_us, NSEC_PER_USEC); 7488 return rt_period_us; 7489} 7490#endif /* CONFIG_RT_GROUP_SCHED */ 7491 7492#ifdef CONFIG_RT_GROUP_SCHED 7493static int sched_rt_global_constraints(void) 7494{ 7495 int ret = 0; 7496 7497 mutex_lock(&rt_constraints_mutex); 7498 read_lock(&tasklist_lock); 7499 ret = __rt_schedulable(NULL, 0, 0); 7500 read_unlock(&tasklist_lock); 7501 mutex_unlock(&rt_constraints_mutex); 7502 7503 return ret; 7504} 7505 7506static int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk) 7507{ 7508 /* Don't accept realtime tasks when there is no way for them to run */ 7509 if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0) 7510 return 0; 7511 7512 return 1; 7513} 7514 7515#else /* !CONFIG_RT_GROUP_SCHED */ 7516static int sched_rt_global_constraints(void) 7517{ 7518 unsigned long flags; 7519 int i, ret = 0; 7520 7521 raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags); 7522 for_each_possible_cpu(i) { 7523 struct rt_rq *rt_rq = &cpu_rq(i)->rt; 7524 7525 raw_spin_lock(&rt_rq->rt_runtime_lock); 7526 rt_rq->rt_runtime = global_rt_runtime(); 7527 raw_spin_unlock(&rt_rq->rt_runtime_lock); 7528 } 7529 raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags); 7530 7531 return ret; 7532} 7533#endif /* CONFIG_RT_GROUP_SCHED */ 7534 7535static int sched_dl_global_constraints(void) 7536{ 7537 u64 runtime = global_rt_runtime(); 7538 u64 period = global_rt_period(); 7539 u64 new_bw = to_ratio(period, runtime); 7540 int cpu, ret = 0; 7541 unsigned long flags; 7542 7543 /* 7544 * Here we want to check the bandwidth not being set to some 7545 * value smaller than the currently allocated bandwidth in 7546 * any of the root_domains. 7547 * 7548 * FIXME: Cycling on all the CPUs is overdoing, but simpler than 7549 * cycling on root_domains... Discussion on different/better 7550 * solutions is welcome! 7551 */ 7552 for_each_possible_cpu(cpu) { 7553 struct dl_bw *dl_b = dl_bw_of(cpu); 7554 7555 raw_spin_lock_irqsave(&dl_b->lock, flags); 7556 if (new_bw < dl_b->total_bw) 7557 ret = -EBUSY; 7558 raw_spin_unlock_irqrestore(&dl_b->lock, flags); 7559 7560 if (ret) 7561 break; 7562 } 7563 7564 return ret; 7565} 7566 7567static void sched_dl_do_global(void) 7568{ 7569 u64 new_bw = -1; 7570 int cpu; 7571 unsigned long flags; 7572 7573 def_dl_bandwidth.dl_period = global_rt_period(); 7574 def_dl_bandwidth.dl_runtime = global_rt_runtime(); 7575 7576 if (global_rt_runtime() != RUNTIME_INF) 7577 new_bw = to_ratio(global_rt_period(), global_rt_runtime()); 7578 7579 /* 7580 * FIXME: As above... 7581 */ 7582 for_each_possible_cpu(cpu) { 7583 struct dl_bw *dl_b = dl_bw_of(cpu); 7584 7585 raw_spin_lock_irqsave(&dl_b->lock, flags); 7586 dl_b->bw = new_bw; 7587 raw_spin_unlock_irqrestore(&dl_b->lock, flags); 7588 } 7589} 7590 7591static int sched_rt_global_validate(void) 7592{ 7593 if (sysctl_sched_rt_period <= 0) 7594 return -EINVAL; 7595 7596 if ((sysctl_sched_rt_runtime != RUNTIME_INF) && 7597 (sysctl_sched_rt_runtime > sysctl_sched_rt_period)) 7598 return -EINVAL; 7599 7600 return 0; 7601} 7602 7603static void sched_rt_do_global(void) 7604{ 7605 def_rt_bandwidth.rt_runtime = global_rt_runtime(); 7606 def_rt_bandwidth.rt_period = ns_to_ktime(global_rt_period()); 7607} 7608 7609int sched_rt_handler(struct ctl_table *table, int write, 7610 void __user *buffer, size_t *lenp, 7611 loff_t *ppos) 7612{ 7613 int old_period, old_runtime; 7614 static DEFINE_MUTEX(mutex); 7615 int ret; 7616 7617 mutex_lock(&mutex); 7618 old_period = sysctl_sched_rt_period; 7619 old_runtime = sysctl_sched_rt_runtime; 7620 7621 ret = proc_dointvec(table, write, buffer, lenp, ppos); 7622 7623 if (!ret && write) { 7624 ret = sched_rt_global_validate(); 7625 if (ret) 7626 goto undo; 7627 7628 ret = sched_rt_global_constraints(); 7629 if (ret) 7630 goto undo; 7631 7632 ret = sched_dl_global_constraints(); 7633 if (ret) 7634 goto undo; 7635 7636 sched_rt_do_global(); 7637 sched_dl_do_global(); 7638 } 7639 if (0) { 7640undo: 7641 sysctl_sched_rt_period = old_period; 7642 sysctl_sched_rt_runtime = old_runtime; 7643 } 7644 mutex_unlock(&mutex); 7645 7646 return ret; 7647} 7648 7649int sched_rr_handler(struct ctl_table *table, int write, 7650 void __user *buffer, size_t *lenp, 7651 loff_t *ppos) 7652{ 7653 int ret; 7654 static DEFINE_MUTEX(mutex); 7655 7656 mutex_lock(&mutex); 7657 ret = proc_dointvec(table, write, buffer, lenp, ppos); 7658 /* make sure that internally we keep jiffies */ 7659 /* also, writing zero resets timeslice to default */ 7660 if (!ret && write) { 7661 sched_rr_timeslice = sched_rr_timeslice <= 0 ? 7662 RR_TIMESLICE : msecs_to_jiffies(sched_rr_timeslice); 7663 } 7664 mutex_unlock(&mutex); 7665 return ret; 7666} 7667 7668#ifdef CONFIG_CGROUP_SCHED 7669 7670static inline struct task_group *css_tg(struct cgroup_subsys_state *css) 7671{ 7672 return css ? container_of(css, struct task_group, css) : NULL; 7673} 7674 7675static struct cgroup_subsys_state * 7676cpu_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) 7677{ 7678 struct task_group *parent = css_tg(parent_css); 7679 struct task_group *tg; 7680 7681 if (!parent) { 7682 /* This is early initialization for the top cgroup */ 7683 return &root_task_group.css; 7684 } 7685 7686 tg = sched_create_group(parent); 7687 if (IS_ERR(tg)) 7688 return ERR_PTR(-ENOMEM); 7689 7690 return &tg->css; 7691} 7692 7693static int cpu_cgroup_css_online(struct cgroup_subsys_state *css) 7694{ 7695 struct task_group *tg = css_tg(css); 7696 struct task_group *parent = css_tg(css->parent); 7697 7698 if (parent) 7699 sched_online_group(tg, parent); 7700 return 0; 7701} 7702 7703static void cpu_cgroup_css_free(struct cgroup_subsys_state *css) 7704{ 7705 struct task_group *tg = css_tg(css); 7706 7707 sched_destroy_group(tg); 7708} 7709 7710static void cpu_cgroup_css_offline(struct cgroup_subsys_state *css) 7711{ 7712 struct task_group *tg = css_tg(css); 7713 7714 sched_offline_group(tg); 7715} 7716 7717static int cpu_cgroup_can_attach(struct cgroup_subsys_state *css, 7718 struct cgroup_taskset *tset) 7719{ 7720 struct task_struct *task; 7721 7722 cgroup_taskset_for_each(task, tset) { 7723#ifdef CONFIG_RT_GROUP_SCHED 7724 if (!sched_rt_can_attach(css_tg(css), task)) 7725 return -EINVAL; 7726#else 7727 /* We don't support RT-tasks being in separate groups */ 7728 if (task->sched_class != &fair_sched_class) 7729 return -EINVAL; 7730#endif 7731 } 7732 return 0; 7733} 7734 7735static void cpu_cgroup_attach(struct cgroup_subsys_state *css, 7736 struct cgroup_taskset *tset) 7737{ 7738 struct task_struct *task; 7739 7740 cgroup_taskset_for_each(task, tset) 7741 sched_move_task(task); 7742} 7743 7744static void cpu_cgroup_exit(struct cgroup_subsys_state *css, 7745 struct cgroup_subsys_state *old_css, 7746 struct task_struct *task) 7747{ 7748 /* 7749 * cgroup_exit() is called in the copy_process() failure path. 7750 * Ignore this case since the task hasn't ran yet, this avoids 7751 * trying to poke a half freed task state from generic code. 7752 */ 7753 if (!(task->flags & PF_EXITING)) 7754 return; 7755 7756 sched_move_task(task); 7757} 7758 7759#ifdef CONFIG_FAIR_GROUP_SCHED 7760static int cpu_shares_write_u64(struct cgroup_subsys_state *css, 7761 struct cftype *cftype, u64 shareval) 7762{ 7763 return sched_group_set_shares(css_tg(css), scale_load(shareval)); 7764} 7765 7766static u64 cpu_shares_read_u64(struct cgroup_subsys_state *css, 7767 struct cftype *cft) 7768{ 7769 struct task_group *tg = css_tg(css); 7770 7771 return (u64) scale_load_down(tg->shares); 7772} 7773 7774#ifdef CONFIG_CFS_BANDWIDTH 7775static DEFINE_MUTEX(cfs_constraints_mutex); 7776 7777const u64 max_cfs_quota_period = 1 * NSEC_PER_SEC; /* 1s */ 7778const u64 min_cfs_quota_period = 1 * NSEC_PER_MSEC; /* 1ms */ 7779 7780static int __cfs_schedulable(struct task_group *tg, u64 period, u64 runtime); 7781 7782static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota) 7783{ 7784 int i, ret = 0, runtime_enabled, runtime_was_enabled; 7785 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 7786 7787 if (tg == &root_task_group) 7788 return -EINVAL; 7789 7790 /* 7791 * Ensure we have at some amount of bandwidth every period. This is 7792 * to prevent reaching a state of large arrears when throttled via 7793 * entity_tick() resulting in prolonged exit starvation. 7794 */ 7795 if (quota < min_cfs_quota_period || period < min_cfs_quota_period) 7796 return -EINVAL; 7797 7798 /* 7799 * Likewise, bound things on the otherside by preventing insane quota 7800 * periods. This also allows us to normalize in computing quota 7801 * feasibility. 7802 */ 7803 if (period > max_cfs_quota_period) 7804 return -EINVAL; 7805 7806 mutex_lock(&cfs_constraints_mutex); 7807 ret = __cfs_schedulable(tg, period, quota); 7808 if (ret) 7809 goto out_unlock; 7810 7811 runtime_enabled = quota != RUNTIME_INF; 7812 runtime_was_enabled = cfs_b->quota != RUNTIME_INF; 7813 /* 7814 * If we need to toggle cfs_bandwidth_used, off->on must occur 7815 * before making related changes, and on->off must occur afterwards 7816 */ 7817 if (runtime_enabled && !runtime_was_enabled) 7818 cfs_bandwidth_usage_inc(); 7819 raw_spin_lock_irq(&cfs_b->lock); 7820 cfs_b->period = ns_to_ktime(period); 7821 cfs_b->quota = quota; 7822 7823 __refill_cfs_bandwidth_runtime(cfs_b); 7824 /* restart the period timer (if active) to handle new period expiry */ 7825 if (runtime_enabled && cfs_b->timer_active) { 7826 /* force a reprogram */ 7827 __start_cfs_bandwidth(cfs_b, true); 7828 } 7829 raw_spin_unlock_irq(&cfs_b->lock); 7830 7831 for_each_possible_cpu(i) { 7832 struct cfs_rq *cfs_rq = tg->cfs_rq[i]; 7833 struct rq *rq = cfs_rq->rq; 7834 7835 raw_spin_lock_irq(&rq->lock); 7836 cfs_rq->runtime_enabled = runtime_enabled; 7837 cfs_rq->runtime_remaining = 0; 7838 7839 if (cfs_rq->throttled) 7840 unthrottle_cfs_rq(cfs_rq); 7841 raw_spin_unlock_irq(&rq->lock); 7842 } 7843 if (runtime_was_enabled && !runtime_enabled) 7844 cfs_bandwidth_usage_dec(); 7845out_unlock: 7846 mutex_unlock(&cfs_constraints_mutex); 7847 7848 return ret; 7849} 7850 7851int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us) 7852{ 7853 u64 quota, period; 7854 7855 period = ktime_to_ns(tg->cfs_bandwidth.period); 7856 if (cfs_quota_us < 0) 7857 quota = RUNTIME_INF; 7858 else 7859 quota = (u64)cfs_quota_us * NSEC_PER_USEC; 7860 7861 return tg_set_cfs_bandwidth(tg, period, quota); 7862} 7863 7864long tg_get_cfs_quota(struct task_group *tg) 7865{ 7866 u64 quota_us; 7867 7868 if (tg->cfs_bandwidth.quota == RUNTIME_INF) 7869 return -1; 7870 7871 quota_us = tg->cfs_bandwidth.quota; 7872 do_div(quota_us, NSEC_PER_USEC); 7873 7874 return quota_us; 7875} 7876 7877int tg_set_cfs_period(struct task_group *tg, long cfs_period_us) 7878{ 7879 u64 quota, period; 7880 7881 period = (u64)cfs_period_us * NSEC_PER_USEC; 7882 quota = tg->cfs_bandwidth.quota; 7883 7884 return tg_set_cfs_bandwidth(tg, period, quota); 7885} 7886 7887long tg_get_cfs_period(struct task_group *tg) 7888{ 7889 u64 cfs_period_us; 7890 7891 cfs_period_us = ktime_to_ns(tg->cfs_bandwidth.period); 7892 do_div(cfs_period_us, NSEC_PER_USEC); 7893 7894 return cfs_period_us; 7895} 7896 7897static s64 cpu_cfs_quota_read_s64(struct cgroup_subsys_state *css, 7898 struct cftype *cft) 7899{ 7900 return tg_get_cfs_quota(css_tg(css)); 7901} 7902 7903static int cpu_cfs_quota_write_s64(struct cgroup_subsys_state *css, 7904 struct cftype *cftype, s64 cfs_quota_us) 7905{ 7906 return tg_set_cfs_quota(css_tg(css), cfs_quota_us); 7907} 7908 7909static u64 cpu_cfs_period_read_u64(struct cgroup_subsys_state *css, 7910 struct cftype *cft) 7911{ 7912 return tg_get_cfs_period(css_tg(css)); 7913} 7914 7915static int cpu_cfs_period_write_u64(struct cgroup_subsys_state *css, 7916 struct cftype *cftype, u64 cfs_period_us) 7917{ 7918 return tg_set_cfs_period(css_tg(css), cfs_period_us); 7919} 7920 7921struct cfs_schedulable_data { 7922 struct task_group *tg; 7923 u64 period, quota; 7924}; 7925 7926/* 7927 * normalize group quota/period to be quota/max_period 7928 * note: units are usecs 7929 */ 7930static u64 normalize_cfs_quota(struct task_group *tg, 7931 struct cfs_schedulable_data *d) 7932{ 7933 u64 quota, period; 7934 7935 if (tg == d->tg) { 7936 period = d->period; 7937 quota = d->quota; 7938 } else { 7939 period = tg_get_cfs_period(tg); 7940 quota = tg_get_cfs_quota(tg); 7941 } 7942 7943 /* note: these should typically be equivalent */ 7944 if (quota == RUNTIME_INF || quota == -1) 7945 return RUNTIME_INF; 7946 7947 return to_ratio(period, quota); 7948} 7949 7950static int tg_cfs_schedulable_down(struct task_group *tg, void *data) 7951{ 7952 struct cfs_schedulable_data *d = data; 7953 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 7954 s64 quota = 0, parent_quota = -1; 7955 7956 if (!tg->parent) { 7957 quota = RUNTIME_INF; 7958 } else { 7959 struct cfs_bandwidth *parent_b = &tg->parent->cfs_bandwidth; 7960 7961 quota = normalize_cfs_quota(tg, d); 7962 parent_quota = parent_b->hierarchal_quota; 7963 7964 /* 7965 * ensure max(child_quota) <= parent_quota, inherit when no 7966 * limit is set 7967 */ 7968 if (quota == RUNTIME_INF) 7969 quota = parent_quota; 7970 else if (parent_quota != RUNTIME_INF && quota > parent_quota) 7971 return -EINVAL; 7972 } 7973 cfs_b->hierarchal_quota = quota; 7974 7975 return 0; 7976} 7977 7978static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota) 7979{ 7980 int ret; 7981 struct cfs_schedulable_data data = { 7982 .tg = tg, 7983 .period = period, 7984 .quota = quota, 7985 }; 7986 7987 if (quota != RUNTIME_INF) { 7988 do_div(data.period, NSEC_PER_USEC); 7989 do_div(data.quota, NSEC_PER_USEC); 7990 } 7991 7992 rcu_read_lock(); 7993 ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data); 7994 rcu_read_unlock(); 7995 7996 return ret; 7997} 7998 7999static int cpu_stats_show(struct seq_file *sf, void *v) 8000{ 8001 struct task_group *tg = css_tg(seq_css(sf)); 8002 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; 8003 8004 seq_printf(sf, "nr_periods %d\n", cfs_b->nr_periods); 8005 seq_printf(sf, "nr_throttled %d\n", cfs_b->nr_throttled); 8006 seq_printf(sf, "throttled_time %llu\n", cfs_b->throttled_time); 8007 8008 return 0; 8009} 8010#endif /* CONFIG_CFS_BANDWIDTH */ 8011#endif /* CONFIG_FAIR_GROUP_SCHED */ 8012 8013#ifdef CONFIG_RT_GROUP_SCHED 8014static int cpu_rt_runtime_write(struct cgroup_subsys_state *css, 8015 struct cftype *cft, s64 val) 8016{ 8017 return sched_group_set_rt_runtime(css_tg(css), val); 8018} 8019 8020static s64 cpu_rt_runtime_read(struct cgroup_subsys_state *css, 8021 struct cftype *cft) 8022{ 8023 return sched_group_rt_runtime(css_tg(css)); 8024} 8025 8026static int cpu_rt_period_write_uint(struct cgroup_subsys_state *css, 8027 struct cftype *cftype, u64 rt_period_us) 8028{ 8029 return sched_group_set_rt_period(css_tg(css), rt_period_us); 8030} 8031 8032static u64 cpu_rt_period_read_uint(struct cgroup_subsys_state *css, 8033 struct cftype *cft) 8034{ 8035 return sched_group_rt_period(css_tg(css)); 8036} 8037#endif /* CONFIG_RT_GROUP_SCHED */ 8038 8039static struct cftype cpu_files[] = { 8040#ifdef CONFIG_FAIR_GROUP_SCHED 8041 { 8042 .name = "shares", 8043 .read_u64 = cpu_shares_read_u64, 8044 .write_u64 = cpu_shares_write_u64, 8045 }, 8046#endif 8047#ifdef CONFIG_CFS_BANDWIDTH 8048 { 8049 .name = "cfs_quota_us", 8050 .read_s64 = cpu_cfs_quota_read_s64, 8051 .write_s64 = cpu_cfs_quota_write_s64, 8052 }, 8053 { 8054 .name = "cfs_period_us", 8055 .read_u64 = cpu_cfs_period_read_u64, 8056 .write_u64 = cpu_cfs_period_write_u64, 8057 }, 8058 { 8059 .name = "stat", 8060 .seq_show = cpu_stats_show, 8061 }, 8062#endif 8063#ifdef CONFIG_RT_GROUP_SCHED 8064 { 8065 .name = "rt_runtime_us", 8066 .read_s64 = cpu_rt_runtime_read, 8067 .write_s64 = cpu_rt_runtime_write, 8068 }, 8069 { 8070 .name = "rt_period_us", 8071 .read_u64 = cpu_rt_period_read_uint, 8072 .write_u64 = cpu_rt_period_write_uint, 8073 }, 8074#endif 8075 { } /* terminate */ 8076}; 8077 8078struct cgroup_subsys cpu_cgrp_subsys = { 8079 .css_alloc = cpu_cgroup_css_alloc, 8080 .css_free = cpu_cgroup_css_free, 8081 .css_online = cpu_cgroup_css_online, 8082 .css_offline = cpu_cgroup_css_offline, 8083 .can_attach = cpu_cgroup_can_attach, 8084 .attach = cpu_cgroup_attach, 8085 .exit = cpu_cgroup_exit, 8086 .base_cftypes = cpu_files, 8087 .early_init = 1, 8088}; 8089 8090#endif /* CONFIG_CGROUP_SCHED */ 8091 8092void dump_cpu_task(int cpu) 8093{ 8094 pr_info("Task dump for CPU %d:\n", cpu); 8095 sched_show_task(cpu_curr(cpu)); 8096} 8097