4 * Kernel scheduler and related syscalls
6 * Copyright (C) 1991-2002 Linus Torvalds
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
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
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
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 <linux/smp_lock.h>
36 #include <asm/mmu_context.h>
37 #include <linux/interrupt.h>
38 #include <linux/capability.h>
39 #include <linux/completion.h>
40 #include <linux/kernel_stat.h>
41 #include <linux/debug_locks.h>
42 #include <linux/perf_event.h>
43 #include <linux/security.h>
44 #include <linux/notifier.h>
45 #include <linux/profile.h>
46 #include <linux/freezer.h>
47 #include <linux/vmalloc.h>
48 #include <linux/blkdev.h>
49 #include <linux/delay.h>
50 #include <linux/pid_namespace.h>
51 #include <linux/smp.h>
52 #include <linux/threads.h>
53 #include <linux/timer.h>
54 #include <linux/rcupdate.h>
55 #include <linux/cpu.h>
56 #include <linux/cpuset.h>
57 #include <linux/percpu.h>
58 #include <linux/kthread.h>
59 #include <linux/proc_fs.h>
60 #include <linux/seq_file.h>
61 #include <linux/sysctl.h>
62 #include <linux/syscalls.h>
63 #include <linux/times.h>
64 #include <linux/tsacct_kern.h>
65 #include <linux/kprobes.h>
66 #include <linux/delayacct.h>
67 #include <linux/unistd.h>
68 #include <linux/pagemap.h>
69 #include <linux/hrtimer.h>
70 #include <linux/tick.h>
71 #include <linux/debugfs.h>
72 #include <linux/ctype.h>
73 #include <linux/ftrace.h>
76 #include <asm/irq_regs.h>
78 #include "sched_cpupri.h"
80 #define CREATE_TRACE_POINTS
81 #include <trace/events/sched.h>
84 * Convert user-nice values [ -20 ... 0 ... 19 ]
85 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
88 #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
89 #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
90 #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
93 * 'User priority' is the nice value converted to something we
94 * can work with better when scaling various scheduler parameters,
95 * it's a [ 0 ... 39 ] range.
97 #define USER_PRIO(p) ((p)-MAX_RT_PRIO)
98 #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
99 #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
102 * Helpers for converting nanosecond timing to jiffy resolution
104 #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
106 #define NICE_0_LOAD SCHED_LOAD_SCALE
107 #define NICE_0_SHIFT SCHED_LOAD_SHIFT
110 * These are the 'tuning knobs' of the scheduler:
112 * default timeslice is 100 msecs (used only for SCHED_RR tasks).
113 * Timeslices get refilled after they expire.
115 #define DEF_TIMESLICE (100 * HZ / 1000)
118 * single value that denotes runtime == period, ie unlimited time.
120 #define RUNTIME_INF ((u64)~0ULL)
122 static inline int rt_policy(int policy)
124 if (unlikely(policy == SCHED_FIFO || policy == SCHED_RR))
129 static inline int task_has_rt_policy(struct task_struct *p)
131 return rt_policy(p->policy);
135 * This is the priority-queue data structure of the RT scheduling class:
137 struct rt_prio_array {
138 DECLARE_BITMAP(bitmap, MAX_RT_PRIO+1); /* include 1 bit for delimiter */
139 struct list_head queue[MAX_RT_PRIO];
142 struct rt_bandwidth {
143 /* nests inside the rq lock: */
144 raw_spinlock_t rt_runtime_lock;
147 struct hrtimer rt_period_timer;
150 static struct rt_bandwidth def_rt_bandwidth;
152 static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun);
154 static enum hrtimer_restart sched_rt_period_timer(struct hrtimer *timer)
156 struct rt_bandwidth *rt_b =
157 container_of(timer, struct rt_bandwidth, rt_period_timer);
163 now = hrtimer_cb_get_time(timer);
164 overrun = hrtimer_forward(timer, now, rt_b->rt_period);
169 idle = do_sched_rt_period_timer(rt_b, overrun);
172 return idle ? HRTIMER_NORESTART : HRTIMER_RESTART;
176 void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime)
178 rt_b->rt_period = ns_to_ktime(period);
179 rt_b->rt_runtime = runtime;
181 raw_spin_lock_init(&rt_b->rt_runtime_lock);
183 hrtimer_init(&rt_b->rt_period_timer,
184 CLOCK_MONOTONIC, HRTIMER_MODE_REL);
185 rt_b->rt_period_timer.function = sched_rt_period_timer;
188 static inline int rt_bandwidth_enabled(void)
190 return sysctl_sched_rt_runtime >= 0;
193 static void start_rt_bandwidth(struct rt_bandwidth *rt_b)
197 if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)
200 if (hrtimer_active(&rt_b->rt_period_timer))
203 raw_spin_lock(&rt_b->rt_runtime_lock);
208 if (hrtimer_active(&rt_b->rt_period_timer))
211 now = hrtimer_cb_get_time(&rt_b->rt_period_timer);
212 hrtimer_forward(&rt_b->rt_period_timer, now, rt_b->rt_period);
214 soft = hrtimer_get_softexpires(&rt_b->rt_period_timer);
215 hard = hrtimer_get_expires(&rt_b->rt_period_timer);
216 delta = ktime_to_ns(ktime_sub(hard, soft));
217 __hrtimer_start_range_ns(&rt_b->rt_period_timer, soft, delta,
218 HRTIMER_MODE_ABS_PINNED, 0);
220 raw_spin_unlock(&rt_b->rt_runtime_lock);
223 #ifdef CONFIG_RT_GROUP_SCHED
224 static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b)
226 hrtimer_cancel(&rt_b->rt_period_timer);
231 * sched_domains_mutex serializes calls to arch_init_sched_domains,
232 * detach_destroy_domains and partition_sched_domains.
234 static DEFINE_MUTEX(sched_domains_mutex);
236 #ifdef CONFIG_CGROUP_SCHED
238 #include <linux/cgroup.h>
242 static LIST_HEAD(task_groups);
244 /* task group related information */
246 struct cgroup_subsys_state css;
248 #ifdef CONFIG_FAIR_GROUP_SCHED
249 /* schedulable entities of this group on each cpu */
250 struct sched_entity **se;
251 /* runqueue "owned" by this group on each cpu */
252 struct cfs_rq **cfs_rq;
253 unsigned long shares;
256 #ifdef CONFIG_RT_GROUP_SCHED
257 struct sched_rt_entity **rt_se;
258 struct rt_rq **rt_rq;
260 struct rt_bandwidth rt_bandwidth;
264 struct list_head list;
266 struct task_group *parent;
267 struct list_head siblings;
268 struct list_head children;
271 #define root_task_group init_task_group
273 /* task_group_lock serializes add/remove of task groups and also changes to
274 * a task group's cpu shares.
276 static DEFINE_SPINLOCK(task_group_lock);
278 #ifdef CONFIG_FAIR_GROUP_SCHED
281 static int root_task_group_empty(void)
283 return list_empty(&root_task_group.children);
287 # define INIT_TASK_GROUP_LOAD NICE_0_LOAD
290 * A weight of 0 or 1 can cause arithmetics problems.
291 * A weight of a cfs_rq is the sum of weights of which entities
292 * are queued on this cfs_rq, so a weight of a entity should not be
293 * too large, so as the shares value of a task group.
294 * (The default weight is 1024 - so there's no practical
295 * limitation from this.)
298 #define MAX_SHARES (1UL << 18)
300 static int init_task_group_load = INIT_TASK_GROUP_LOAD;
303 /* Default task group.
304 * Every task in system belong to this group at bootup.
306 struct task_group init_task_group;
308 /* return group to which a task belongs */
309 static inline struct task_group *task_group(struct task_struct *p)
311 struct task_group *tg;
313 #ifdef CONFIG_CGROUP_SCHED
314 tg = container_of(task_subsys_state(p, cpu_cgroup_subsys_id),
315 struct task_group, css);
317 tg = &init_task_group;
322 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
323 static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
325 #ifdef CONFIG_FAIR_GROUP_SCHED
326 p->se.cfs_rq = task_group(p)->cfs_rq[cpu];
327 p->se.parent = task_group(p)->se[cpu];
330 #ifdef CONFIG_RT_GROUP_SCHED
331 p->rt.rt_rq = task_group(p)->rt_rq[cpu];
332 p->rt.parent = task_group(p)->rt_se[cpu];
338 static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { }
339 static inline struct task_group *task_group(struct task_struct *p)
344 #endif /* CONFIG_CGROUP_SCHED */
346 /* CFS-related fields in a runqueue */
348 struct load_weight load;
349 unsigned long nr_running;
354 struct rb_root tasks_timeline;
355 struct rb_node *rb_leftmost;
357 struct list_head tasks;
358 struct list_head *balance_iterator;
361 * 'curr' points to currently running entity on this cfs_rq.
362 * It is set to NULL otherwise (i.e when none are currently running).
364 struct sched_entity *curr, *next, *last;
366 unsigned int nr_spread_over;
368 #ifdef CONFIG_FAIR_GROUP_SCHED
369 struct rq *rq; /* cpu runqueue to which this cfs_rq is attached */
372 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
373 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
374 * (like users, containers etc.)
376 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
377 * list is used during load balance.
379 struct list_head leaf_cfs_rq_list;
380 struct task_group *tg; /* group that "owns" this runqueue */
384 * the part of load.weight contributed by tasks
386 unsigned long task_weight;
389 * h_load = weight * f(tg)
391 * Where f(tg) is the recursive weight fraction assigned to
394 unsigned long h_load;
397 * this cpu's part of tg->shares
399 unsigned long shares;
402 * load.weight at the time we set shares
404 unsigned long rq_weight;
409 /* Real-Time classes' related field in a runqueue: */
411 struct rt_prio_array active;
412 unsigned long rt_nr_running;
413 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
415 int curr; /* highest queued rt task prio */
417 int next; /* next highest */
422 unsigned long rt_nr_migratory;
423 unsigned long rt_nr_total;
425 struct plist_head pushable_tasks;
430 /* Nests inside the rq lock: */
431 raw_spinlock_t rt_runtime_lock;
433 #ifdef CONFIG_RT_GROUP_SCHED
434 unsigned long rt_nr_boosted;
437 struct list_head leaf_rt_rq_list;
438 struct task_group *tg;
445 * We add the notion of a root-domain which will be used to define per-domain
446 * variables. Each exclusive cpuset essentially defines an island domain by
447 * fully partitioning the member cpus from any other cpuset. Whenever a new
448 * exclusive cpuset is created, we also create and attach a new root-domain
455 cpumask_var_t online;
458 * The "RT overload" flag: it gets set if a CPU has more than
459 * one runnable RT task.
461 cpumask_var_t rto_mask;
464 struct cpupri cpupri;
469 * By default the system creates a single root-domain with all cpus as
470 * members (mimicking the global state we have today).
472 static struct root_domain def_root_domain;
477 * This is the main, per-CPU runqueue data structure.
479 * Locking rule: those places that want to lock multiple runqueues
480 * (such as the load balancing or the thread migration code), lock
481 * acquire operations must be ordered by ascending &runqueue.
488 * nr_running and cpu_load should be in the same cacheline because
489 * remote CPUs use both these fields when doing load calculation.
491 unsigned long nr_running;
492 #define CPU_LOAD_IDX_MAX 5
493 unsigned long cpu_load[CPU_LOAD_IDX_MAX];
496 unsigned char in_nohz_recently;
498 unsigned int skip_clock_update;
500 /* capture load from *all* tasks on this cpu: */
501 struct load_weight load;
502 unsigned long nr_load_updates;
508 #ifdef CONFIG_FAIR_GROUP_SCHED
509 /* list of leaf cfs_rq on this cpu: */
510 struct list_head leaf_cfs_rq_list;
512 #ifdef CONFIG_RT_GROUP_SCHED
513 struct list_head leaf_rt_rq_list;
517 * This is part of a global counter where only the total sum
518 * over all CPUs matters. A task can increase this counter on
519 * one CPU and if it got migrated afterwards it may decrease
520 * it on another CPU. Always updated under the runqueue lock:
522 unsigned long nr_uninterruptible;
524 struct task_struct *curr, *idle;
525 unsigned long next_balance;
526 struct mm_struct *prev_mm;
533 struct root_domain *rd;
534 struct sched_domain *sd;
536 unsigned char idle_at_tick;
537 /* For active balancing */
541 /* cpu of this runqueue: */
545 unsigned long avg_load_per_task;
547 struct task_struct *migration_thread;
548 struct list_head migration_queue;
556 /* calc_load related fields */
557 unsigned long calc_load_update;
558 long calc_load_active;
560 #ifdef CONFIG_SCHED_HRTICK
562 int hrtick_csd_pending;
563 struct call_single_data hrtick_csd;
565 struct hrtimer hrtick_timer;
568 #ifdef CONFIG_SCHEDSTATS
570 struct sched_info rq_sched_info;
571 unsigned long long rq_cpu_time;
572 /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
574 /* sys_sched_yield() stats */
575 unsigned int yld_count;
577 /* schedule() stats */
578 unsigned int sched_switch;
579 unsigned int sched_count;
580 unsigned int sched_goidle;
582 /* try_to_wake_up() stats */
583 unsigned int ttwu_count;
584 unsigned int ttwu_local;
587 unsigned int bkl_count;
591 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
594 void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags)
596 rq->curr->sched_class->check_preempt_curr(rq, p, flags);
599 * A queue event has occurred, and we're going to schedule. In
600 * this case, we can save a useless back to back clock update.
602 if (test_tsk_need_resched(p))
603 rq->skip_clock_update = 1;
606 static inline int cpu_of(struct rq *rq)
615 #define rcu_dereference_check_sched_domain(p) \
616 rcu_dereference_check((p), \
617 rcu_read_lock_sched_held() || \
618 lockdep_is_held(&sched_domains_mutex))
621 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
622 * See detach_destroy_domains: synchronize_sched for details.
624 * The domain tree of any CPU may only be accessed from within
625 * preempt-disabled sections.
627 #define for_each_domain(cpu, __sd) \
628 for (__sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
630 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
631 #define this_rq() (&__get_cpu_var(runqueues))
632 #define task_rq(p) cpu_rq(task_cpu(p))
633 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
634 #define raw_rq() (&__raw_get_cpu_var(runqueues))
636 inline void update_rq_clock(struct rq *rq)
638 if (!rq->skip_clock_update)
639 rq->clock = sched_clock_cpu(cpu_of(rq));
643 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
645 #ifdef CONFIG_SCHED_DEBUG
646 # define const_debug __read_mostly
648 # define const_debug static const
653 * @cpu: the processor in question.
655 * Returns true if the current cpu runqueue is locked.
656 * This interface allows printk to be called with the runqueue lock
657 * held and know whether or not it is OK to wake up the klogd.
659 int runqueue_is_locked(int cpu)
661 return raw_spin_is_locked(&cpu_rq(cpu)->lock);
665 * Debugging: various feature bits
668 #define SCHED_FEAT(name, enabled) \
669 __SCHED_FEAT_##name ,
672 #include "sched_features.h"
677 #define SCHED_FEAT(name, enabled) \
678 (1UL << __SCHED_FEAT_##name) * enabled |
680 const_debug unsigned int sysctl_sched_features =
681 #include "sched_features.h"
686 #ifdef CONFIG_SCHED_DEBUG
687 #define SCHED_FEAT(name, enabled) \
690 static __read_mostly char *sched_feat_names[] = {
691 #include "sched_features.h"
697 static int sched_feat_show(struct seq_file *m, void *v)
701 for (i = 0; sched_feat_names[i]; i++) {
702 if (!(sysctl_sched_features & (1UL << i)))
704 seq_printf(m, "%s ", sched_feat_names[i]);
712 sched_feat_write(struct file *filp, const char __user *ubuf,
713 size_t cnt, loff_t *ppos)
723 if (copy_from_user(&buf, ubuf, cnt))
728 if (strncmp(buf, "NO_", 3) == 0) {
733 for (i = 0; sched_feat_names[i]; i++) {
734 int len = strlen(sched_feat_names[i]);
736 if (strncmp(cmp, sched_feat_names[i], len) == 0) {
738 sysctl_sched_features &= ~(1UL << i);
740 sysctl_sched_features |= (1UL << i);
745 if (!sched_feat_names[i])
753 static int sched_feat_open(struct inode *inode, struct file *filp)
755 return single_open(filp, sched_feat_show, NULL);
758 static const struct file_operations sched_feat_fops = {
759 .open = sched_feat_open,
760 .write = sched_feat_write,
763 .release = single_release,
766 static __init int sched_init_debug(void)
768 debugfs_create_file("sched_features", 0644, NULL, NULL,
773 late_initcall(sched_init_debug);
777 #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
780 * Number of tasks to iterate in a single balance run.
781 * Limited because this is done with IRQs disabled.
783 const_debug unsigned int sysctl_sched_nr_migrate = 32;
786 * ratelimit for updating the group shares.
789 unsigned int sysctl_sched_shares_ratelimit = 250000;
790 unsigned int normalized_sysctl_sched_shares_ratelimit = 250000;
793 * Inject some fuzzyness into changing the per-cpu group shares
794 * this avoids remote rq-locks at the expense of fairness.
797 unsigned int sysctl_sched_shares_thresh = 4;
800 * period over which we average the RT time consumption, measured
805 const_debug unsigned int sysctl_sched_time_avg = MSEC_PER_SEC;
808 * period over which we measure -rt task cpu usage in us.
811 unsigned int sysctl_sched_rt_period = 1000000;
813 static __read_mostly int scheduler_running;
816 * part of the period that we allow rt tasks to run in us.
819 int sysctl_sched_rt_runtime = 950000;
821 static inline u64 global_rt_period(void)
823 return (u64)sysctl_sched_rt_period * NSEC_PER_USEC;
826 static inline u64 global_rt_runtime(void)
828 if (sysctl_sched_rt_runtime < 0)
831 return (u64)sysctl_sched_rt_runtime * NSEC_PER_USEC;
834 #ifndef prepare_arch_switch
835 # define prepare_arch_switch(next) do { } while (0)
837 #ifndef finish_arch_switch
838 # define finish_arch_switch(prev) do { } while (0)
841 static inline int task_current(struct rq *rq, struct task_struct *p)
843 return rq->curr == p;
846 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
847 static inline int task_running(struct rq *rq, struct task_struct *p)
849 return task_current(rq, p);
852 static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
856 static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
858 #ifdef CONFIG_DEBUG_SPINLOCK
859 /* this is a valid case when another task releases the spinlock */
860 rq->lock.owner = current;
863 * If we are tracking spinlock dependencies then we have to
864 * fix up the runqueue lock - which gets 'carried over' from
867 spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_);
869 raw_spin_unlock_irq(&rq->lock);
872 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
873 static inline int task_running(struct rq *rq, struct task_struct *p)
878 return task_current(rq, p);
882 static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
886 * We can optimise this out completely for !SMP, because the
887 * SMP rebalancing from interrupt is the only thing that cares
892 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
893 raw_spin_unlock_irq(&rq->lock);
895 raw_spin_unlock(&rq->lock);
899 static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
903 * After ->oncpu is cleared, the task can be moved to a different CPU.
904 * We must ensure this doesn't happen until the switch is completely
910 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
914 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
917 * Check whether the task is waking, we use this to synchronize against
918 * ttwu() so that task_cpu() reports a stable number.
920 * We need to make an exception for PF_STARTING tasks because the fork
921 * path might require task_rq_lock() to work, eg. it can call
922 * set_cpus_allowed_ptr() from the cpuset clone_ns code.
924 static inline int task_is_waking(struct task_struct *p)
926 return unlikely((p->state == TASK_WAKING) && !(p->flags & PF_STARTING));
930 * __task_rq_lock - lock the runqueue a given task resides on.
931 * Must be called interrupts disabled.
933 static inline struct rq *__task_rq_lock(struct task_struct *p)
939 while (task_is_waking(p))
942 raw_spin_lock(&rq->lock);
943 if (likely(rq == task_rq(p) && !task_is_waking(p)))
945 raw_spin_unlock(&rq->lock);
950 * task_rq_lock - lock the runqueue a given task resides on and disable
951 * interrupts. Note the ordering: we can safely lookup the task_rq without
952 * explicitly disabling preemption.
954 static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags)
960 while (task_is_waking(p))
962 local_irq_save(*flags);
964 raw_spin_lock(&rq->lock);
965 if (likely(rq == task_rq(p) && !task_is_waking(p)))
967 raw_spin_unlock_irqrestore(&rq->lock, *flags);
971 void task_rq_unlock_wait(struct task_struct *p)
973 struct rq *rq = task_rq(p);
975 smp_mb(); /* spin-unlock-wait is not a full memory barrier */
976 raw_spin_unlock_wait(&rq->lock);
979 static void __task_rq_unlock(struct rq *rq)
982 raw_spin_unlock(&rq->lock);
985 static inline void task_rq_unlock(struct rq *rq, unsigned long *flags)
988 raw_spin_unlock_irqrestore(&rq->lock, *flags);
992 * this_rq_lock - lock this runqueue and disable interrupts.
994 static struct rq *this_rq_lock(void)
1001 raw_spin_lock(&rq->lock);
1006 #ifdef CONFIG_SCHED_HRTICK
1008 * Use HR-timers to deliver accurate preemption points.
1010 * Its all a bit involved since we cannot program an hrt while holding the
1011 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
1014 * When we get rescheduled we reprogram the hrtick_timer outside of the
1020 * - enabled by features
1021 * - hrtimer is actually high res
1023 static inline int hrtick_enabled(struct rq *rq)
1025 if (!sched_feat(HRTICK))
1027 if (!cpu_active(cpu_of(rq)))
1029 return hrtimer_is_hres_active(&rq->hrtick_timer);
1032 static void hrtick_clear(struct rq *rq)
1034 if (hrtimer_active(&rq->hrtick_timer))
1035 hrtimer_cancel(&rq->hrtick_timer);
1039 * High-resolution timer tick.
1040 * Runs from hardirq context with interrupts disabled.
1042 static enum hrtimer_restart hrtick(struct hrtimer *timer)
1044 struct rq *rq = container_of(timer, struct rq, hrtick_timer);
1046 WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
1048 raw_spin_lock(&rq->lock);
1049 update_rq_clock(rq);
1050 rq->curr->sched_class->task_tick(rq, rq->curr, 1);
1051 raw_spin_unlock(&rq->lock);
1053 return HRTIMER_NORESTART;
1058 * called from hardirq (IPI) context
1060 static void __hrtick_start(void *arg)
1062 struct rq *rq = arg;
1064 raw_spin_lock(&rq->lock);
1065 hrtimer_restart(&rq->hrtick_timer);
1066 rq->hrtick_csd_pending = 0;
1067 raw_spin_unlock(&rq->lock);
1071 * Called to set the hrtick timer state.
1073 * called with rq->lock held and irqs disabled
1075 static void hrtick_start(struct rq *rq, u64 delay)
1077 struct hrtimer *timer = &rq->hrtick_timer;
1078 ktime_t time = ktime_add_ns(timer->base->get_time(), delay);
1080 hrtimer_set_expires(timer, time);
1082 if (rq == this_rq()) {
1083 hrtimer_restart(timer);
1084 } else if (!rq->hrtick_csd_pending) {
1085 __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd, 0);
1086 rq->hrtick_csd_pending = 1;
1091 hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu)
1093 int cpu = (int)(long)hcpu;
1096 case CPU_UP_CANCELED:
1097 case CPU_UP_CANCELED_FROZEN:
1098 case CPU_DOWN_PREPARE:
1099 case CPU_DOWN_PREPARE_FROZEN:
1101 case CPU_DEAD_FROZEN:
1102 hrtick_clear(cpu_rq(cpu));
1109 static __init void init_hrtick(void)
1111 hotcpu_notifier(hotplug_hrtick, 0);
1115 * Called to set the hrtick timer state.
1117 * called with rq->lock held and irqs disabled
1119 static void hrtick_start(struct rq *rq, u64 delay)
1121 __hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0,
1122 HRTIMER_MODE_REL_PINNED, 0);
1125 static inline void init_hrtick(void)
1128 #endif /* CONFIG_SMP */
1130 static void init_rq_hrtick(struct rq *rq)
1133 rq->hrtick_csd_pending = 0;
1135 rq->hrtick_csd.flags = 0;
1136 rq->hrtick_csd.func = __hrtick_start;
1137 rq->hrtick_csd.info = rq;
1140 hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1141 rq->hrtick_timer.function = hrtick;
1143 #else /* CONFIG_SCHED_HRTICK */
1144 static inline void hrtick_clear(struct rq *rq)
1148 static inline void init_rq_hrtick(struct rq *rq)
1152 static inline void init_hrtick(void)
1155 #endif /* CONFIG_SCHED_HRTICK */
1158 * resched_task - mark a task 'to be rescheduled now'.
1160 * On UP this means the setting of the need_resched flag, on SMP it
1161 * might also involve a cross-CPU call to trigger the scheduler on
1166 #ifndef tsk_is_polling
1167 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1170 static void resched_task(struct task_struct *p)
1174 assert_raw_spin_locked(&task_rq(p)->lock);
1176 if (test_tsk_need_resched(p))
1179 set_tsk_need_resched(p);
1182 if (cpu == smp_processor_id())
1185 /* NEED_RESCHED must be visible before we test polling */
1187 if (!tsk_is_polling(p))
1188 smp_send_reschedule(cpu);
1191 static void resched_cpu(int cpu)
1193 struct rq *rq = cpu_rq(cpu);
1194 unsigned long flags;
1196 if (!raw_spin_trylock_irqsave(&rq->lock, flags))
1198 resched_task(cpu_curr(cpu));
1199 raw_spin_unlock_irqrestore(&rq->lock, flags);
1204 * When add_timer_on() enqueues a timer into the timer wheel of an
1205 * idle CPU then this timer might expire before the next timer event
1206 * which is scheduled to wake up that CPU. In case of a completely
1207 * idle system the next event might even be infinite time into the
1208 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1209 * leaves the inner idle loop so the newly added timer is taken into
1210 * account when the CPU goes back to idle and evaluates the timer
1211 * wheel for the next timer event.
1213 void wake_up_idle_cpu(int cpu)
1215 struct rq *rq = cpu_rq(cpu);
1217 if (cpu == smp_processor_id())
1221 * This is safe, as this function is called with the timer
1222 * wheel base lock of (cpu) held. When the CPU is on the way
1223 * to idle and has not yet set rq->curr to idle then it will
1224 * be serialized on the timer wheel base lock and take the new
1225 * timer into account automatically.
1227 if (rq->curr != rq->idle)
1231 * We can set TIF_RESCHED on the idle task of the other CPU
1232 * lockless. The worst case is that the other CPU runs the
1233 * idle task through an additional NOOP schedule()
1235 set_tsk_need_resched(rq->idle);
1237 /* NEED_RESCHED must be visible before we test polling */
1239 if (!tsk_is_polling(rq->idle))
1240 smp_send_reschedule(cpu);
1243 int nohz_ratelimit(int cpu)
1245 struct rq *rq = cpu_rq(cpu);
1246 u64 diff = rq->clock - rq->nohz_stamp;
1248 rq->nohz_stamp = rq->clock;
1250 return diff < (NSEC_PER_SEC / HZ) >> 1;
1253 #endif /* CONFIG_NO_HZ */
1255 static u64 sched_avg_period(void)
1257 return (u64)sysctl_sched_time_avg * NSEC_PER_MSEC / 2;
1260 static void sched_avg_update(struct rq *rq)
1262 s64 period = sched_avg_period();
1264 while ((s64)(rq->clock - rq->age_stamp) > period) {
1265 rq->age_stamp += period;
1270 static void sched_rt_avg_update(struct rq *rq, u64 rt_delta)
1272 rq->rt_avg += rt_delta;
1273 sched_avg_update(rq);
1276 #else /* !CONFIG_SMP */
1277 static void resched_task(struct task_struct *p)
1279 assert_raw_spin_locked(&task_rq(p)->lock);
1280 set_tsk_need_resched(p);
1283 static void sched_rt_avg_update(struct rq *rq, u64 rt_delta)
1286 #endif /* CONFIG_SMP */
1288 #if BITS_PER_LONG == 32
1289 # define WMULT_CONST (~0UL)
1291 # define WMULT_CONST (1UL << 32)
1294 #define WMULT_SHIFT 32
1297 * Shift right and round:
1299 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1302 * delta *= weight / lw
1304 static unsigned long
1305 calc_delta_mine(unsigned long delta_exec, unsigned long weight,
1306 struct load_weight *lw)
1310 if (!lw->inv_weight) {
1311 if (BITS_PER_LONG > 32 && unlikely(lw->weight >= WMULT_CONST))
1314 lw->inv_weight = 1 + (WMULT_CONST-lw->weight/2)
1318 tmp = (u64)delta_exec * weight;
1320 * Check whether we'd overflow the 64-bit multiplication:
1322 if (unlikely(tmp > WMULT_CONST))
1323 tmp = SRR(SRR(tmp, WMULT_SHIFT/2) * lw->inv_weight,
1326 tmp = SRR(tmp * lw->inv_weight, WMULT_SHIFT);
1328 return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX);
1331 static inline void update_load_add(struct load_weight *lw, unsigned long inc)
1337 static inline void update_load_sub(struct load_weight *lw, unsigned long dec)
1344 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1345 * of tasks with abnormal "nice" values across CPUs the contribution that
1346 * each task makes to its run queue's load is weighted according to its
1347 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1348 * scaled version of the new time slice allocation that they receive on time
1352 #define WEIGHT_IDLEPRIO 3
1353 #define WMULT_IDLEPRIO 1431655765
1356 * Nice levels are multiplicative, with a gentle 10% change for every
1357 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1358 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1359 * that remained on nice 0.
1361 * The "10% effect" is relative and cumulative: from _any_ nice level,
1362 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1363 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1364 * If a task goes up by ~10% and another task goes down by ~10% then
1365 * the relative distance between them is ~25%.)
1367 static const int prio_to_weight[40] = {
1368 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1369 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1370 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1371 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1372 /* 0 */ 1024, 820, 655, 526, 423,
1373 /* 5 */ 335, 272, 215, 172, 137,
1374 /* 10 */ 110, 87, 70, 56, 45,
1375 /* 15 */ 36, 29, 23, 18, 15,
1379 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1381 * In cases where the weight does not change often, we can use the
1382 * precalculated inverse to speed up arithmetics by turning divisions
1383 * into multiplications:
1385 static const u32 prio_to_wmult[40] = {
1386 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1387 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1388 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1389 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1390 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1391 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1392 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1393 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1396 /* Time spent by the tasks of the cpu accounting group executing in ... */
1397 enum cpuacct_stat_index {
1398 CPUACCT_STAT_USER, /* ... user mode */
1399 CPUACCT_STAT_SYSTEM, /* ... kernel mode */
1401 CPUACCT_STAT_NSTATS,
1404 #ifdef CONFIG_CGROUP_CPUACCT
1405 static void cpuacct_charge(struct task_struct *tsk, u64 cputime);
1406 static void cpuacct_update_stats(struct task_struct *tsk,
1407 enum cpuacct_stat_index idx, cputime_t val);
1409 static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}
1410 static inline void cpuacct_update_stats(struct task_struct *tsk,
1411 enum cpuacct_stat_index idx, cputime_t val) {}
1414 static inline void inc_cpu_load(struct rq *rq, unsigned long load)
1416 update_load_add(&rq->load, load);
1419 static inline void dec_cpu_load(struct rq *rq, unsigned long load)
1421 update_load_sub(&rq->load, load);
1424 #if (defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)) || defined(CONFIG_RT_GROUP_SCHED)
1425 typedef int (*tg_visitor)(struct task_group *, void *);
1428 * Iterate the full tree, calling @down when first entering a node and @up when
1429 * leaving it for the final time.
1431 static int walk_tg_tree(tg_visitor down, tg_visitor up, void *data)
1433 struct task_group *parent, *child;
1437 parent = &root_task_group;
1439 ret = (*down)(parent, data);
1442 list_for_each_entry_rcu(child, &parent->children, siblings) {
1449 ret = (*up)(parent, data);
1454 parent = parent->parent;
1463 static int tg_nop(struct task_group *tg, void *data)
1470 /* Used instead of source_load when we know the type == 0 */
1471 static unsigned long weighted_cpuload(const int cpu)
1473 return cpu_rq(cpu)->load.weight;
1477 * Return a low guess at the load of a migration-source cpu weighted
1478 * according to the scheduling class and "nice" value.
1480 * We want to under-estimate the load of migration sources, to
1481 * balance conservatively.
1483 static unsigned long source_load(int cpu, int type)
1485 struct rq *rq = cpu_rq(cpu);
1486 unsigned long total = weighted_cpuload(cpu);
1488 if (type == 0 || !sched_feat(LB_BIAS))
1491 return min(rq->cpu_load[type-1], total);
1495 * Return a high guess at the load of a migration-target cpu weighted
1496 * according to the scheduling class and "nice" value.
1498 static unsigned long target_load(int cpu, int type)
1500 struct rq *rq = cpu_rq(cpu);
1501 unsigned long total = weighted_cpuload(cpu);
1503 if (type == 0 || !sched_feat(LB_BIAS))
1506 return max(rq->cpu_load[type-1], total);
1509 static struct sched_group *group_of(int cpu)
1511 struct sched_domain *sd = rcu_dereference_sched(cpu_rq(cpu)->sd);
1519 static unsigned long power_of(int cpu)
1521 struct sched_group *group = group_of(cpu);
1524 return SCHED_LOAD_SCALE;
1526 return group->cpu_power;
1529 static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd);
1531 static unsigned long cpu_avg_load_per_task(int cpu)
1533 struct rq *rq = cpu_rq(cpu);
1534 unsigned long nr_running = ACCESS_ONCE(rq->nr_running);
1537 rq->avg_load_per_task = rq->load.weight / nr_running;
1539 rq->avg_load_per_task = 0;
1541 return rq->avg_load_per_task;
1544 #ifdef CONFIG_FAIR_GROUP_SCHED
1546 static __read_mostly unsigned long __percpu *update_shares_data;
1548 static void __set_se_shares(struct sched_entity *se, unsigned long shares);
1551 * Calculate and set the cpu's group shares.
1553 static void update_group_shares_cpu(struct task_group *tg, int cpu,
1554 unsigned long sd_shares,
1555 unsigned long sd_rq_weight,
1556 unsigned long *usd_rq_weight)
1558 unsigned long shares, rq_weight;
1561 rq_weight = usd_rq_weight[cpu];
1564 rq_weight = NICE_0_LOAD;
1568 * \Sum_j shares_j * rq_weight_i
1569 * shares_i = -----------------------------
1570 * \Sum_j rq_weight_j
1572 shares = (sd_shares * rq_weight) / sd_rq_weight;
1573 shares = clamp_t(unsigned long, shares, MIN_SHARES, MAX_SHARES);
1575 if (abs(shares - tg->se[cpu]->load.weight) >
1576 sysctl_sched_shares_thresh) {
1577 struct rq *rq = cpu_rq(cpu);
1578 unsigned long flags;
1580 raw_spin_lock_irqsave(&rq->lock, flags);
1581 tg->cfs_rq[cpu]->rq_weight = boost ? 0 : rq_weight;
1582 tg->cfs_rq[cpu]->shares = boost ? 0 : shares;
1583 __set_se_shares(tg->se[cpu], shares);
1584 raw_spin_unlock_irqrestore(&rq->lock, flags);
1589 * Re-compute the task group their per cpu shares over the given domain.
1590 * This needs to be done in a bottom-up fashion because the rq weight of a
1591 * parent group depends on the shares of its child groups.
1593 static int tg_shares_up(struct task_group *tg, void *data)
1595 unsigned long weight, rq_weight = 0, sum_weight = 0, shares = 0;
1596 unsigned long *usd_rq_weight;
1597 struct sched_domain *sd = data;
1598 unsigned long flags;
1604 local_irq_save(flags);
1605 usd_rq_weight = per_cpu_ptr(update_shares_data, smp_processor_id());
1607 for_each_cpu(i, sched_domain_span(sd)) {
1608 weight = tg->cfs_rq[i]->load.weight;
1609 usd_rq_weight[i] = weight;
1611 rq_weight += weight;
1613 * If there are currently no tasks on the cpu pretend there
1614 * is one of average load so that when a new task gets to
1615 * run here it will not get delayed by group starvation.
1618 weight = NICE_0_LOAD;
1620 sum_weight += weight;
1621 shares += tg->cfs_rq[i]->shares;
1625 rq_weight = sum_weight;
1627 if ((!shares && rq_weight) || shares > tg->shares)
1628 shares = tg->shares;
1630 if (!sd->parent || !(sd->parent->flags & SD_LOAD_BALANCE))
1631 shares = tg->shares;
1633 for_each_cpu(i, sched_domain_span(sd))
1634 update_group_shares_cpu(tg, i, shares, rq_weight, usd_rq_weight);
1636 local_irq_restore(flags);
1642 * Compute the cpu's hierarchical load factor for each task group.
1643 * This needs to be done in a top-down fashion because the load of a child
1644 * group is a fraction of its parents load.
1646 static int tg_load_down(struct task_group *tg, void *data)
1649 long cpu = (long)data;
1652 load = cpu_rq(cpu)->load.weight;
1654 load = tg->parent->cfs_rq[cpu]->h_load;
1655 load *= tg->cfs_rq[cpu]->shares;
1656 load /= tg->parent->cfs_rq[cpu]->load.weight + 1;
1659 tg->cfs_rq[cpu]->h_load = load;
1664 static void update_shares(struct sched_domain *sd)
1669 if (root_task_group_empty())
1672 now = cpu_clock(raw_smp_processor_id());
1673 elapsed = now - sd->last_update;
1675 if (elapsed >= (s64)(u64)sysctl_sched_shares_ratelimit) {
1676 sd->last_update = now;
1677 walk_tg_tree(tg_nop, tg_shares_up, sd);
1681 static void update_h_load(long cpu)
1683 if (root_task_group_empty())
1686 walk_tg_tree(tg_load_down, tg_nop, (void *)cpu);
1691 static inline void update_shares(struct sched_domain *sd)
1697 #ifdef CONFIG_PREEMPT
1699 static void double_rq_lock(struct rq *rq1, struct rq *rq2);
1702 * fair double_lock_balance: Safely acquires both rq->locks in a fair
1703 * way at the expense of forcing extra atomic operations in all
1704 * invocations. This assures that the double_lock is acquired using the
1705 * same underlying policy as the spinlock_t on this architecture, which
1706 * reduces latency compared to the unfair variant below. However, it
1707 * also adds more overhead and therefore may reduce throughput.
1709 static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
1710 __releases(this_rq->lock)
1711 __acquires(busiest->lock)
1712 __acquires(this_rq->lock)
1714 raw_spin_unlock(&this_rq->lock);
1715 double_rq_lock(this_rq, busiest);
1722 * Unfair double_lock_balance: Optimizes throughput at the expense of
1723 * latency by eliminating extra atomic operations when the locks are
1724 * already in proper order on entry. This favors lower cpu-ids and will
1725 * grant the double lock to lower cpus over higher ids under contention,
1726 * regardless of entry order into the function.
1728 static int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
1729 __releases(this_rq->lock)
1730 __acquires(busiest->lock)
1731 __acquires(this_rq->lock)
1735 if (unlikely(!raw_spin_trylock(&busiest->lock))) {
1736 if (busiest < this_rq) {
1737 raw_spin_unlock(&this_rq->lock);
1738 raw_spin_lock(&busiest->lock);
1739 raw_spin_lock_nested(&this_rq->lock,
1740 SINGLE_DEPTH_NESTING);
1743 raw_spin_lock_nested(&busiest->lock,
1744 SINGLE_DEPTH_NESTING);
1749 #endif /* CONFIG_PREEMPT */
1752 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
1754 static int double_lock_balance(struct rq *this_rq, struct rq *busiest)
1756 if (unlikely(!irqs_disabled())) {
1757 /* printk() doesn't work good under rq->lock */
1758 raw_spin_unlock(&this_rq->lock);
1762 return _double_lock_balance(this_rq, busiest);
1765 static inline void double_unlock_balance(struct rq *this_rq, struct rq *busiest)
1766 __releases(busiest->lock)
1768 raw_spin_unlock(&busiest->lock);
1769 lock_set_subclass(&this_rq->lock.dep_map, 0, _RET_IP_);
1773 * double_rq_lock - safely lock two runqueues
1775 * Note this does not disable interrupts like task_rq_lock,
1776 * you need to do so manually before calling.
1778 static void double_rq_lock(struct rq *rq1, struct rq *rq2)
1779 __acquires(rq1->lock)
1780 __acquires(rq2->lock)
1782 BUG_ON(!irqs_disabled());
1784 raw_spin_lock(&rq1->lock);
1785 __acquire(rq2->lock); /* Fake it out ;) */
1788 raw_spin_lock(&rq1->lock);
1789 raw_spin_lock_nested(&rq2->lock, SINGLE_DEPTH_NESTING);
1791 raw_spin_lock(&rq2->lock);
1792 raw_spin_lock_nested(&rq1->lock, SINGLE_DEPTH_NESTING);
1798 * double_rq_unlock - safely unlock two runqueues
1800 * Note this does not restore interrupts like task_rq_unlock,
1801 * you need to do so manually after calling.
1803 static void double_rq_unlock(struct rq *rq1, struct rq *rq2)
1804 __releases(rq1->lock)
1805 __releases(rq2->lock)
1807 raw_spin_unlock(&rq1->lock);
1809 raw_spin_unlock(&rq2->lock);
1811 __release(rq2->lock);
1816 #ifdef CONFIG_FAIR_GROUP_SCHED
1817 static void cfs_rq_set_shares(struct cfs_rq *cfs_rq, unsigned long shares)
1820 cfs_rq->shares = shares;
1825 static void calc_load_account_active(struct rq *this_rq);
1826 static void update_sysctl(void);
1827 static int get_update_sysctl_factor(void);
1829 static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
1831 set_task_rq(p, cpu);
1834 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1835 * successfuly executed on another CPU. We must ensure that updates of
1836 * per-task data have been completed by this moment.
1839 task_thread_info(p)->cpu = cpu;
1843 static const struct sched_class rt_sched_class;
1845 #define sched_class_highest (&rt_sched_class)
1846 #define for_each_class(class) \
1847 for (class = sched_class_highest; class; class = class->next)
1849 #include "sched_stats.h"
1851 static void inc_nr_running(struct rq *rq)
1856 static void dec_nr_running(struct rq *rq)
1861 static void set_load_weight(struct task_struct *p)
1863 if (task_has_rt_policy(p)) {
1864 p->se.load.weight = prio_to_weight[0] * 2;
1865 p->se.load.inv_weight = prio_to_wmult[0] >> 1;
1870 * SCHED_IDLE tasks get minimal weight:
1872 if (p->policy == SCHED_IDLE) {
1873 p->se.load.weight = WEIGHT_IDLEPRIO;
1874 p->se.load.inv_weight = WMULT_IDLEPRIO;
1878 p->se.load.weight = prio_to_weight[p->static_prio - MAX_RT_PRIO];
1879 p->se.load.inv_weight = prio_to_wmult[p->static_prio - MAX_RT_PRIO];
1882 static void update_avg(u64 *avg, u64 sample)
1884 s64 diff = sample - *avg;
1889 enqueue_task(struct rq *rq, struct task_struct *p, int wakeup, bool head)
1891 update_rq_clock(rq);
1892 sched_info_queued(p);
1893 p->sched_class->enqueue_task(rq, p, wakeup, head);
1897 static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep)
1899 update_rq_clock(rq);
1900 sched_info_dequeued(p);
1901 p->sched_class->dequeue_task(rq, p, sleep);
1906 * activate_task - move a task to the runqueue.
1908 static void activate_task(struct rq *rq, struct task_struct *p, int wakeup)
1910 if (task_contributes_to_load(p))
1911 rq->nr_uninterruptible--;
1913 enqueue_task(rq, p, wakeup, false);
1918 * deactivate_task - remove a task from the runqueue.
1920 static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep)
1922 if (task_contributes_to_load(p))
1923 rq->nr_uninterruptible++;
1925 dequeue_task(rq, p, sleep);
1929 #include "sched_idletask.c"
1930 #include "sched_fair.c"
1931 #include "sched_rt.c"
1932 #ifdef CONFIG_SCHED_DEBUG
1933 # include "sched_debug.c"
1937 * __normal_prio - return the priority that is based on the static prio
1939 static inline int __normal_prio(struct task_struct *p)
1941 return p->static_prio;
1945 * Calculate the expected normal priority: i.e. priority
1946 * without taking RT-inheritance into account. Might be
1947 * boosted by interactivity modifiers. Changes upon fork,
1948 * setprio syscalls, and whenever the interactivity
1949 * estimator recalculates.
1951 static inline int normal_prio(struct task_struct *p)
1955 if (task_has_rt_policy(p))
1956 prio = MAX_RT_PRIO-1 - p->rt_priority;
1958 prio = __normal_prio(p);
1963 * Calculate the current priority, i.e. the priority
1964 * taken into account by the scheduler. This value might
1965 * be boosted by RT tasks, or might be boosted by
1966 * interactivity modifiers. Will be RT if the task got
1967 * RT-boosted. If not then it returns p->normal_prio.
1969 static int effective_prio(struct task_struct *p)
1971 p->normal_prio = normal_prio(p);
1973 * If we are RT tasks or we were boosted to RT priority,
1974 * keep the priority unchanged. Otherwise, update priority
1975 * to the normal priority:
1977 if (!rt_prio(p->prio))
1978 return p->normal_prio;
1983 * task_curr - is this task currently executing on a CPU?
1984 * @p: the task in question.
1986 inline int task_curr(const struct task_struct *p)
1988 return cpu_curr(task_cpu(p)) == p;
1991 static inline void check_class_changed(struct rq *rq, struct task_struct *p,
1992 const struct sched_class *prev_class,
1993 int oldprio, int running)
1995 if (prev_class != p->sched_class) {
1996 if (prev_class->switched_from)
1997 prev_class->switched_from(rq, p, running);
1998 p->sched_class->switched_to(rq, p, running);
2000 p->sched_class->prio_changed(rq, p, oldprio, running);
2005 * Is this task likely cache-hot:
2008 task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
2012 if (p->sched_class != &fair_sched_class)
2016 * Buddy candidates are cache hot:
2018 if (sched_feat(CACHE_HOT_BUDDY) && this_rq()->nr_running &&
2019 (&p->se == cfs_rq_of(&p->se)->next ||
2020 &p->se == cfs_rq_of(&p->se)->last))
2023 if (sysctl_sched_migration_cost == -1)
2025 if (sysctl_sched_migration_cost == 0)
2028 delta = now - p->se.exec_start;
2030 return delta < (s64)sysctl_sched_migration_cost;
2033 void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
2035 #ifdef CONFIG_SCHED_DEBUG
2037 * We should never call set_task_cpu() on a blocked task,
2038 * ttwu() will sort out the placement.
2040 WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING &&
2041 !(task_thread_info(p)->preempt_count & PREEMPT_ACTIVE));
2044 trace_sched_migrate_task(p, new_cpu);
2046 if (task_cpu(p) != new_cpu) {
2047 p->se.nr_migrations++;
2048 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, 1, 1, NULL, 0);
2051 __set_task_cpu(p, new_cpu);
2054 struct migration_req {
2055 struct list_head list;
2057 struct task_struct *task;
2060 struct completion done;
2064 * The task's runqueue lock must be held.
2065 * Returns true if you have to wait for migration thread.
2068 migrate_task(struct task_struct *p, int dest_cpu, struct migration_req *req)
2070 struct rq *rq = task_rq(p);
2073 * If the task is not on a runqueue (and not running), then
2074 * the next wake-up will properly place the task.
2076 if (!p->se.on_rq && !task_running(rq, p))
2079 init_completion(&req->done);
2081 req->dest_cpu = dest_cpu;
2082 list_add(&req->list, &rq->migration_queue);
2088 * wait_task_context_switch - wait for a thread to complete at least one
2091 * @p must not be current.
2093 void wait_task_context_switch(struct task_struct *p)
2095 unsigned long nvcsw, nivcsw, flags;
2103 * The runqueue is assigned before the actual context
2104 * switch. We need to take the runqueue lock.
2106 * We could check initially without the lock but it is
2107 * very likely that we need to take the lock in every
2110 rq = task_rq_lock(p, &flags);
2111 running = task_running(rq, p);
2112 task_rq_unlock(rq, &flags);
2114 if (likely(!running))
2117 * The switch count is incremented before the actual
2118 * context switch. We thus wait for two switches to be
2119 * sure at least one completed.
2121 if ((p->nvcsw - nvcsw) > 1)
2123 if ((p->nivcsw - nivcsw) > 1)
2131 * wait_task_inactive - wait for a thread to unschedule.
2133 * If @match_state is nonzero, it's the @p->state value just checked and
2134 * not expected to change. If it changes, i.e. @p might have woken up,
2135 * then return zero. When we succeed in waiting for @p to be off its CPU,
2136 * we return a positive number (its total switch count). If a second call
2137 * a short while later returns the same number, the caller can be sure that
2138 * @p has remained unscheduled the whole time.
2140 * The caller must ensure that the task *will* unschedule sometime soon,
2141 * else this function might spin for a *long* time. This function can't
2142 * be called with interrupts off, or it may introduce deadlock with
2143 * smp_call_function() if an IPI is sent by the same process we are
2144 * waiting to become inactive.
2146 unsigned long wait_task_inactive(struct task_struct *p, long match_state)
2148 unsigned long flags;
2155 * We do the initial early heuristics without holding
2156 * any task-queue locks at all. We'll only try to get
2157 * the runqueue lock when things look like they will
2163 * If the task is actively running on another CPU
2164 * still, just relax and busy-wait without holding
2167 * NOTE! Since we don't hold any locks, it's not
2168 * even sure that "rq" stays as the right runqueue!
2169 * But we don't care, since "task_running()" will
2170 * return false if the runqueue has changed and p
2171 * is actually now running somewhere else!
2173 while (task_running(rq, p)) {
2174 if (match_state && unlikely(p->state != match_state))
2180 * Ok, time to look more closely! We need the rq
2181 * lock now, to be *sure*. If we're wrong, we'll
2182 * just go back and repeat.
2184 rq = task_rq_lock(p, &flags);
2185 trace_sched_wait_task(rq, p);
2186 running = task_running(rq, p);
2187 on_rq = p->se.on_rq;
2189 if (!match_state || p->state == match_state)
2190 ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
2191 task_rq_unlock(rq, &flags);
2194 * If it changed from the expected state, bail out now.
2196 if (unlikely(!ncsw))
2200 * Was it really running after all now that we
2201 * checked with the proper locks actually held?
2203 * Oops. Go back and try again..
2205 if (unlikely(running)) {
2211 * It's not enough that it's not actively running,
2212 * it must be off the runqueue _entirely_, and not
2215 * So if it was still runnable (but just not actively
2216 * running right now), it's preempted, and we should
2217 * yield - it could be a while.
2219 if (unlikely(on_rq)) {
2220 schedule_timeout_uninterruptible(1);
2225 * Ahh, all good. It wasn't running, and it wasn't
2226 * runnable, which means that it will never become
2227 * running in the future either. We're all done!
2236 * kick_process - kick a running thread to enter/exit the kernel
2237 * @p: the to-be-kicked thread
2239 * Cause a process which is running on another CPU to enter
2240 * kernel-mode, without any delay. (to get signals handled.)
2242 * NOTE: this function doesnt have to take the runqueue lock,
2243 * because all it wants to ensure is that the remote task enters
2244 * the kernel. If the IPI races and the task has been migrated
2245 * to another CPU then no harm is done and the purpose has been
2248 void kick_process(struct task_struct *p)
2254 if ((cpu != smp_processor_id()) && task_curr(p))
2255 smp_send_reschedule(cpu);
2258 EXPORT_SYMBOL_GPL(kick_process);
2259 #endif /* CONFIG_SMP */
2262 * task_oncpu_function_call - call a function on the cpu on which a task runs
2263 * @p: the task to evaluate
2264 * @func: the function to be called
2265 * @info: the function call argument
2267 * Calls the function @func when the task is currently running. This might
2268 * be on the current CPU, which just calls the function directly
2270 void task_oncpu_function_call(struct task_struct *p,
2271 void (*func) (void *info), void *info)
2278 smp_call_function_single(cpu, func, info, 1);
2283 static int select_fallback_rq(int cpu, struct task_struct *p)
2286 const struct cpumask *nodemask = cpumask_of_node(cpu_to_node(cpu));
2288 /* Look for allowed, online CPU in same node. */
2289 for_each_cpu_and(dest_cpu, nodemask, cpu_active_mask)
2290 if (cpumask_test_cpu(dest_cpu, &p->cpus_allowed))
2293 /* Any allowed, online CPU? */
2294 dest_cpu = cpumask_any_and(&p->cpus_allowed, cpu_active_mask);
2295 if (dest_cpu < nr_cpu_ids)
2298 /* No more Mr. Nice Guy. */
2299 if (unlikely(dest_cpu >= nr_cpu_ids)) {
2300 cpumask_copy(&p->cpus_allowed, cpu_possible_mask);
2301 dest_cpu = cpumask_any(cpu_active_mask);
2304 * Don't tell them about moving exiting tasks or
2305 * kernel threads (both mm NULL), since they never
2308 if (p->mm && printk_ratelimit()) {
2309 printk(KERN_INFO "process %d (%s) no "
2310 "longer affine to cpu%d\n",
2311 task_pid_nr(p), p->comm, cpu);
2319 * Gets called from 3 sites (exec, fork, wakeup), since it is called without
2320 * holding rq->lock we need to ensure ->cpus_allowed is stable, this is done
2323 * exec: is unstable, retry loop
2324 * fork & wake-up: serialize ->cpus_allowed against TASK_WAKING
2327 int select_task_rq(struct task_struct *p, int sd_flags, int wake_flags)
2329 int cpu = p->sched_class->select_task_rq(p, sd_flags, wake_flags);
2332 * In order not to call set_task_cpu() on a blocking task we need
2333 * to rely on ttwu() to place the task on a valid ->cpus_allowed
2336 * Since this is common to all placement strategies, this lives here.
2338 * [ this allows ->select_task() to simply return task_cpu(p) and
2339 * not worry about this generic constraint ]
2341 if (unlikely(!cpumask_test_cpu(cpu, &p->cpus_allowed) ||
2343 cpu = select_fallback_rq(task_cpu(p), p);
2350 * try_to_wake_up - wake up a thread
2351 * @p: the to-be-woken-up thread
2352 * @state: the mask of task states that can be woken
2353 * @sync: do a synchronous wakeup?
2355 * Put it on the run-queue if it's not already there. The "current"
2356 * thread is always on the run-queue (except when the actual
2357 * re-schedule is in progress), and as such you're allowed to do
2358 * the simpler "current->state = TASK_RUNNING" to mark yourself
2359 * runnable without the overhead of this.
2361 * returns failure only if the task is already active.
2363 static int try_to_wake_up(struct task_struct *p, unsigned int state,
2366 int cpu, orig_cpu, this_cpu, success = 0;
2367 unsigned long flags;
2370 this_cpu = get_cpu();
2373 rq = task_rq_lock(p, &flags);
2374 if (!(p->state & state))
2384 if (unlikely(task_running(rq, p)))
2388 * In order to handle concurrent wakeups and release the rq->lock
2389 * we put the task in TASK_WAKING state.
2391 * First fix up the nr_uninterruptible count:
2393 if (task_contributes_to_load(p))
2394 rq->nr_uninterruptible--;
2395 p->state = TASK_WAKING;
2397 if (p->sched_class->task_waking)
2398 p->sched_class->task_waking(rq, p);
2400 __task_rq_unlock(rq);
2402 cpu = select_task_rq(p, SD_BALANCE_WAKE, wake_flags);
2403 if (cpu != orig_cpu) {
2405 * Since we migrate the task without holding any rq->lock,
2406 * we need to be careful with task_rq_lock(), since that
2407 * might end up locking an invalid rq.
2409 set_task_cpu(p, cpu);
2413 raw_spin_lock(&rq->lock);
2416 * We migrated the task without holding either rq->lock, however
2417 * since the task is not on the task list itself, nobody else
2418 * will try and migrate the task, hence the rq should match the
2419 * cpu we just moved it to.
2421 WARN_ON(task_cpu(p) != cpu);
2422 WARN_ON(p->state != TASK_WAKING);
2424 #ifdef CONFIG_SCHEDSTATS
2425 schedstat_inc(rq, ttwu_count);
2426 if (cpu == this_cpu)
2427 schedstat_inc(rq, ttwu_local);
2429 struct sched_domain *sd;
2430 for_each_domain(this_cpu, sd) {
2431 if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
2432 schedstat_inc(sd, ttwu_wake_remote);
2437 #endif /* CONFIG_SCHEDSTATS */
2440 #endif /* CONFIG_SMP */
2441 schedstat_inc(p, se.statistics.nr_wakeups);
2442 if (wake_flags & WF_SYNC)
2443 schedstat_inc(p, se.statistics.nr_wakeups_sync);
2444 if (orig_cpu != cpu)
2445 schedstat_inc(p, se.statistics.nr_wakeups_migrate);
2446 if (cpu == this_cpu)
2447 schedstat_inc(p, se.statistics.nr_wakeups_local);
2449 schedstat_inc(p, se.statistics.nr_wakeups_remote);
2450 activate_task(rq, p, 1);
2454 trace_sched_wakeup(rq, p, success);
2455 check_preempt_curr(rq, p, wake_flags);
2457 p->state = TASK_RUNNING;
2459 if (p->sched_class->task_woken)
2460 p->sched_class->task_woken(rq, p);
2462 if (unlikely(rq->idle_stamp)) {
2463 u64 delta = rq->clock - rq->idle_stamp;
2464 u64 max = 2*sysctl_sched_migration_cost;
2469 update_avg(&rq->avg_idle, delta);
2474 task_rq_unlock(rq, &flags);
2481 * wake_up_process - Wake up a specific process
2482 * @p: The process to be woken up.
2484 * Attempt to wake up the nominated process and move it to the set of runnable
2485 * processes. Returns 1 if the process was woken up, 0 if it was already
2488 * It may be assumed that this function implies a write memory barrier before
2489 * changing the task state if and only if any tasks are woken up.
2491 int wake_up_process(struct task_struct *p)
2493 return try_to_wake_up(p, TASK_ALL, 0);
2495 EXPORT_SYMBOL(wake_up_process);
2497 int wake_up_state(struct task_struct *p, unsigned int state)
2499 return try_to_wake_up(p, state, 0);
2503 * Perform scheduler related setup for a newly forked process p.
2504 * p is forked by current.
2506 * __sched_fork() is basic setup used by init_idle() too:
2508 static void __sched_fork(struct task_struct *p)
2510 p->se.exec_start = 0;
2511 p->se.sum_exec_runtime = 0;
2512 p->se.prev_sum_exec_runtime = 0;
2513 p->se.nr_migrations = 0;
2515 #ifdef CONFIG_SCHEDSTATS
2516 memset(&p->se.statistics, 0, sizeof(p->se.statistics));
2519 INIT_LIST_HEAD(&p->rt.run_list);
2521 INIT_LIST_HEAD(&p->se.group_node);
2523 #ifdef CONFIG_PREEMPT_NOTIFIERS
2524 INIT_HLIST_HEAD(&p->preempt_notifiers);
2529 * fork()/clone()-time setup:
2531 void sched_fork(struct task_struct *p, int clone_flags)
2533 int cpu = get_cpu();
2537 * We mark the process as waking here. This guarantees that
2538 * nobody will actually run it, and a signal or other external
2539 * event cannot wake it up and insert it on the runqueue either.
2541 p->state = TASK_WAKING;
2544 * Revert to default priority/policy on fork if requested.
2546 if (unlikely(p->sched_reset_on_fork)) {
2547 if (p->policy == SCHED_FIFO || p->policy == SCHED_RR) {
2548 p->policy = SCHED_NORMAL;
2549 p->normal_prio = p->static_prio;
2552 if (PRIO_TO_NICE(p->static_prio) < 0) {
2553 p->static_prio = NICE_TO_PRIO(0);
2554 p->normal_prio = p->static_prio;
2559 * We don't need the reset flag anymore after the fork. It has
2560 * fulfilled its duty:
2562 p->sched_reset_on_fork = 0;
2566 * Make sure we do not leak PI boosting priority to the child.
2568 p->prio = current->normal_prio;
2570 if (!rt_prio(p->prio))
2571 p->sched_class = &fair_sched_class;
2573 if (p->sched_class->task_fork)
2574 p->sched_class->task_fork(p);
2576 set_task_cpu(p, cpu);
2578 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2579 if (likely(sched_info_on()))
2580 memset(&p->sched_info, 0, sizeof(p->sched_info));
2582 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
2585 #ifdef CONFIG_PREEMPT
2586 /* Want to start with kernel preemption disabled. */
2587 task_thread_info(p)->preempt_count = 1;
2589 plist_node_init(&p->pushable_tasks, MAX_PRIO);
2595 * wake_up_new_task - wake up a newly created task for the first time.
2597 * This function will do some initial scheduler statistics housekeeping
2598 * that must be done for every newly created context, then puts the task
2599 * on the runqueue and wakes it.
2601 void wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
2603 unsigned long flags;
2605 int cpu __maybe_unused = get_cpu();
2609 * Fork balancing, do it here and not earlier because:
2610 * - cpus_allowed can change in the fork path
2611 * - any previously selected cpu might disappear through hotplug
2613 * We still have TASK_WAKING but PF_STARTING is gone now, meaning
2614 * ->cpus_allowed is stable, we have preemption disabled, meaning
2615 * cpu_online_mask is stable.
2617 cpu = select_task_rq(p, SD_BALANCE_FORK, 0);
2618 set_task_cpu(p, cpu);
2622 * Since the task is not on the rq and we still have TASK_WAKING set
2623 * nobody else will migrate this task.
2626 raw_spin_lock_irqsave(&rq->lock, flags);
2628 BUG_ON(p->state != TASK_WAKING);
2629 p->state = TASK_RUNNING;
2630 activate_task(rq, p, 0);
2631 trace_sched_wakeup_new(rq, p, 1);
2632 check_preempt_curr(rq, p, WF_FORK);
2634 if (p->sched_class->task_woken)
2635 p->sched_class->task_woken(rq, p);
2637 task_rq_unlock(rq, &flags);
2641 #ifdef CONFIG_PREEMPT_NOTIFIERS
2644 * preempt_notifier_register - tell me when current is being preempted & rescheduled
2645 * @notifier: notifier struct to register
2647 void preempt_notifier_register(struct preempt_notifier *notifier)
2649 hlist_add_head(¬ifier->link, ¤t->preempt_notifiers);
2651 EXPORT_SYMBOL_GPL(preempt_notifier_register);
2654 * preempt_notifier_unregister - no longer interested in preemption notifications
2655 * @notifier: notifier struct to unregister
2657 * This is safe to call from within a preemption notifier.
2659 void preempt_notifier_unregister(struct preempt_notifier *notifier)
2661 hlist_del(¬ifier->link);
2663 EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
2665 static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
2667 struct preempt_notifier *notifier;
2668 struct hlist_node *node;
2670 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
2671 notifier->ops->sched_in(notifier, raw_smp_processor_id());
2675 fire_sched_out_preempt_notifiers(struct task_struct *curr,
2676 struct task_struct *next)
2678 struct preempt_notifier *notifier;
2679 struct hlist_node *node;
2681 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
2682 notifier->ops->sched_out(notifier, next);
2685 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2687 static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
2692 fire_sched_out_preempt_notifiers(struct task_struct *curr,
2693 struct task_struct *next)
2697 #endif /* CONFIG_PREEMPT_NOTIFIERS */
2700 * prepare_task_switch - prepare to switch tasks
2701 * @rq: the runqueue preparing to switch
2702 * @prev: the current task that is being switched out
2703 * @next: the task we are going to switch to.
2705 * This is called with the rq lock held and interrupts off. It must
2706 * be paired with a subsequent finish_task_switch after the context
2709 * prepare_task_switch sets up locking and calls architecture specific
2713 prepare_task_switch(struct rq *rq, struct task_struct *prev,
2714 struct task_struct *next)
2716 fire_sched_out_preempt_notifiers(prev, next);
2717 prepare_lock_switch(rq, next);
2718 prepare_arch_switch(next);
2722 * finish_task_switch - clean up after a task-switch
2723 * @rq: runqueue associated with task-switch
2724 * @prev: the thread we just switched away from.
2726 * finish_task_switch must be called after the context switch, paired
2727 * with a prepare_task_switch call before the context switch.
2728 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2729 * and do any other architecture-specific cleanup actions.
2731 * Note that we may have delayed dropping an mm in context_switch(). If
2732 * so, we finish that here outside of the runqueue lock. (Doing it
2733 * with the lock held can cause deadlocks; see schedule() for
2736 static void finish_task_switch(struct rq *rq, struct task_struct *prev)
2737 __releases(rq->lock)
2739 struct mm_struct *mm = rq->prev_mm;
2745 * A task struct has one reference for the use as "current".
2746 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2747 * schedule one last time. The schedule call will never return, and
2748 * the scheduled task must drop that reference.
2749 * The test for TASK_DEAD must occur while the runqueue locks are
2750 * still held, otherwise prev could be scheduled on another cpu, die
2751 * there before we look at prev->state, and then the reference would
2753 * Manfred Spraul <manfred@colorfullife.com>
2755 prev_state = prev->state;
2756 finish_arch_switch(prev);
2757 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
2758 local_irq_disable();
2759 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
2760 perf_event_task_sched_in(current);
2761 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
2763 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
2764 finish_lock_switch(rq, prev);
2766 fire_sched_in_preempt_notifiers(current);
2769 if (unlikely(prev_state == TASK_DEAD)) {
2771 * Remove function-return probe instances associated with this
2772 * task and put them back on the free list.
2774 kprobe_flush_task(prev);
2775 put_task_struct(prev);
2781 /* assumes rq->lock is held */
2782 static inline void pre_schedule(struct rq *rq, struct task_struct *prev)
2784 if (prev->sched_class->pre_schedule)
2785 prev->sched_class->pre_schedule(rq, prev);
2788 /* rq->lock is NOT held, but preemption is disabled */
2789 static inline void post_schedule(struct rq *rq)
2791 if (rq->post_schedule) {
2792 unsigned long flags;
2794 raw_spin_lock_irqsave(&rq->lock, flags);
2795 if (rq->curr->sched_class->post_schedule)
2796 rq->curr->sched_class->post_schedule(rq);
2797 raw_spin_unlock_irqrestore(&rq->lock, flags);
2799 rq->post_schedule = 0;
2805 static inline void pre_schedule(struct rq *rq, struct task_struct *p)
2809 static inline void post_schedule(struct rq *rq)
2816 * schedule_tail - first thing a freshly forked thread must call.
2817 * @prev: the thread we just switched away from.
2819 asmlinkage void schedule_tail(struct task_struct *prev)
2820 __releases(rq->lock)
2822 struct rq *rq = this_rq();
2824 finish_task_switch(rq, prev);
2827 * FIXME: do we need to worry about rq being invalidated by the
2832 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2833 /* In this case, finish_task_switch does not reenable preemption */
2836 if (current->set_child_tid)
2837 put_user(task_pid_vnr(current), current->set_child_tid);
2841 * context_switch - switch to the new MM and the new
2842 * thread's register state.
2845 context_switch(struct rq *rq, struct task_struct *prev,
2846 struct task_struct *next)
2848 struct mm_struct *mm, *oldmm;
2850 prepare_task_switch(rq, prev, next);
2851 trace_sched_switch(rq, prev, next);
2853 oldmm = prev->active_mm;
2855 * For paravirt, this is coupled with an exit in switch_to to
2856 * combine the page table reload and the switch backend into
2859 arch_start_context_switch(prev);
2862 next->active_mm = oldmm;
2863 atomic_inc(&oldmm->mm_count);
2864 enter_lazy_tlb(oldmm, next);
2866 switch_mm(oldmm, mm, next);
2868 if (likely(!prev->mm)) {
2869 prev->active_mm = NULL;
2870 rq->prev_mm = oldmm;
2873 * Since the runqueue lock will be released by the next
2874 * task (which is an invalid locking op but in the case
2875 * of the scheduler it's an obvious special-case), so we
2876 * do an early lockdep release here:
2878 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2879 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
2882 /* Here we just switch the register state and the stack. */
2883 switch_to(prev, next, prev);
2887 * this_rq must be evaluated again because prev may have moved
2888 * CPUs since it called schedule(), thus the 'rq' on its stack
2889 * frame will be invalid.
2891 finish_task_switch(this_rq(), prev);
2895 * nr_running, nr_uninterruptible and nr_context_switches:
2897 * externally visible scheduler statistics: current number of runnable
2898 * threads, current number of uninterruptible-sleeping threads, total
2899 * number of context switches performed since bootup.
2901 unsigned long nr_running(void)
2903 unsigned long i, sum = 0;
2905 for_each_online_cpu(i)
2906 sum += cpu_rq(i)->nr_running;
2911 unsigned long nr_uninterruptible(void)
2913 unsigned long i, sum = 0;
2915 for_each_possible_cpu(i)
2916 sum += cpu_rq(i)->nr_uninterruptible;
2919 * Since we read the counters lockless, it might be slightly
2920 * inaccurate. Do not allow it to go below zero though:
2922 if (unlikely((long)sum < 0))
2928 unsigned long long nr_context_switches(void)
2931 unsigned long long sum = 0;
2933 for_each_possible_cpu(i)
2934 sum += cpu_rq(i)->nr_switches;
2939 unsigned long nr_iowait(void)
2941 unsigned long i, sum = 0;
2943 for_each_possible_cpu(i)
2944 sum += atomic_read(&cpu_rq(i)->nr_iowait);
2949 unsigned long nr_iowait_cpu(void)
2951 struct rq *this = this_rq();
2952 return atomic_read(&this->nr_iowait);
2955 unsigned long this_cpu_load(void)
2957 struct rq *this = this_rq();
2958 return this->cpu_load[0];
2962 /* Variables and functions for calc_load */
2963 static atomic_long_t calc_load_tasks;
2964 static unsigned long calc_load_update;
2965 unsigned long avenrun[3];
2966 EXPORT_SYMBOL(avenrun);
2969 * get_avenrun - get the load average array
2970 * @loads: pointer to dest load array
2971 * @offset: offset to add
2972 * @shift: shift count to shift the result left
2974 * These values are estimates at best, so no need for locking.
2976 void get_avenrun(unsigned long *loads, unsigned long offset, int shift)
2978 loads[0] = (avenrun[0] + offset) << shift;
2979 loads[1] = (avenrun[1] + offset) << shift;
2980 loads[2] = (avenrun[2] + offset) << shift;
2983 static unsigned long
2984 calc_load(unsigned long load, unsigned long exp, unsigned long active)
2987 load += active * (FIXED_1 - exp);
2988 return load >> FSHIFT;
2992 * calc_load - update the avenrun load estimates 10 ticks after the
2993 * CPUs have updated calc_load_tasks.
2995 void calc_global_load(void)
2997 unsigned long upd = calc_load_update + 10;
3000 if (time_before(jiffies, upd))
3003 active = atomic_long_read(&calc_load_tasks);
3004 active = active > 0 ? active * FIXED_1 : 0;
3006 avenrun[0] = calc_load(avenrun[0], EXP_1, active);
3007 avenrun[1] = calc_load(avenrun[1], EXP_5, active);
3008 avenrun[2] = calc_load(avenrun[2], EXP_15, active);
3010 calc_load_update += LOAD_FREQ;
3014 * Either called from update_cpu_load() or from a cpu going idle
3016 static void calc_load_account_active(struct rq *this_rq)
3018 long nr_active, delta;
3020 nr_active = this_rq->nr_running;
3021 nr_active += (long) this_rq->nr_uninterruptible;
3023 if (nr_active != this_rq->calc_load_active) {
3024 delta = nr_active - this_rq->calc_load_active;
3025 this_rq->calc_load_active = nr_active;
3026 atomic_long_add(delta, &calc_load_tasks);
3031 * Update rq->cpu_load[] statistics. This function is usually called every
3032 * scheduler tick (TICK_NSEC).
3034 static void update_cpu_load(struct rq *this_rq)
3036 unsigned long this_load = this_rq->load.weight;
3039 this_rq->nr_load_updates++;
3041 /* Update our load: */
3042 for (i = 0, scale = 1; i < CPU_LOAD_IDX_MAX; i++, scale += scale) {
3043 unsigned long old_load, new_load;
3045 /* scale is effectively 1 << i now, and >> i divides by scale */
3047 old_load = this_rq->cpu_load[i];
3048 new_load = this_load;
3050 * Round up the averaging division if load is increasing. This
3051 * prevents us from getting stuck on 9 if the load is 10, for
3054 if (new_load > old_load)
3055 new_load += scale-1;
3056 this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) >> i;
3059 if (time_after_eq(jiffies, this_rq->calc_load_update)) {
3060 this_rq->calc_load_update += LOAD_FREQ;
3061 calc_load_account_active(this_rq);
3068 * sched_exec - execve() is a valuable balancing opportunity, because at
3069 * this point the task has the smallest effective memory and cache footprint.
3071 void sched_exec(void)
3073 struct task_struct *p = current;
3074 struct migration_req req;
3075 int dest_cpu, this_cpu;
3076 unsigned long flags;
3080 this_cpu = get_cpu();
3081 dest_cpu = select_task_rq(p, SD_BALANCE_EXEC, 0);
3082 if (dest_cpu == this_cpu) {
3087 rq = task_rq_lock(p, &flags);
3091 * select_task_rq() can race against ->cpus_allowed
3093 if (!cpumask_test_cpu(dest_cpu, &p->cpus_allowed)
3094 || unlikely(!cpu_active(dest_cpu))) {
3095 task_rq_unlock(rq, &flags);
3099 /* force the process onto the specified CPU */
3100 if (migrate_task(p, dest_cpu, &req)) {
3101 /* Need to wait for migration thread (might exit: take ref). */
3102 struct task_struct *mt = rq->migration_thread;
3104 get_task_struct(mt);
3105 task_rq_unlock(rq, &flags);
3106 wake_up_process(mt);
3107 put_task_struct(mt);
3108 wait_for_completion(&req.done);
3112 task_rq_unlock(rq, &flags);
3117 DEFINE_PER_CPU(struct kernel_stat, kstat);
3119 EXPORT_PER_CPU_SYMBOL(kstat);
3122 * Return any ns on the sched_clock that have not yet been accounted in
3123 * @p in case that task is currently running.
3125 * Called with task_rq_lock() held on @rq.
3127 static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq)
3131 if (task_current(rq, p)) {
3132 update_rq_clock(rq);
3133 ns = rq->clock - p->se.exec_start;
3141 unsigned long long task_delta_exec(struct task_struct *p)
3143 unsigned long flags;
3147 rq = task_rq_lock(p, &flags);
3148 ns = do_task_delta_exec(p, rq);
3149 task_rq_unlock(rq, &flags);
3155 * Return accounted runtime for the task.
3156 * In case the task is currently running, return the runtime plus current's
3157 * pending runtime that have not been accounted yet.
3159 unsigned long long task_sched_runtime(struct task_struct *p)
3161 unsigned long flags;
3165 rq = task_rq_lock(p, &flags);
3166 ns = p->se.sum_exec_runtime + do_task_delta_exec(p, rq);
3167 task_rq_unlock(rq, &flags);
3173 * Return sum_exec_runtime for the thread group.
3174 * In case the task is currently running, return the sum plus current's
3175 * pending runtime that have not been accounted yet.
3177 * Note that the thread group might have other running tasks as well,
3178 * so the return value not includes other pending runtime that other
3179 * running tasks might have.
3181 unsigned long long thread_group_sched_runtime(struct task_struct *p)
3183 struct task_cputime totals;
3184 unsigned long flags;
3188 rq = task_rq_lock(p, &flags);
3189 thread_group_cputime(p, &totals);
3190 ns = totals.sum_exec_runtime + do_task_delta_exec(p, rq);
3191 task_rq_unlock(rq, &flags);
3197 * Account user cpu time to a process.
3198 * @p: the process that the cpu time gets accounted to
3199 * @cputime: the cpu time spent in user space since the last update
3200 * @cputime_scaled: cputime scaled by cpu frequency
3202 void account_user_time(struct task_struct *p, cputime_t cputime,
3203 cputime_t cputime_scaled)
3205 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
3208 /* Add user time to process. */
3209 p->utime = cputime_add(p->utime, cputime);
3210 p->utimescaled = cputime_add(p->utimescaled, cputime_scaled);
3211 account_group_user_time(p, cputime);
3213 /* Add user time to cpustat. */
3214 tmp = cputime_to_cputime64(cputime);
3215 if (TASK_NICE(p) > 0)
3216 cpustat->nice = cputime64_add(cpustat->nice, tmp);
3218 cpustat->user = cputime64_add(cpustat->user, tmp);
3220 cpuacct_update_stats(p, CPUACCT_STAT_USER, cputime);
3221 /* Account for user time used */
3222 acct_update_integrals(p);
3226 * Account guest cpu time to a process.
3227 * @p: the process that the cpu time gets accounted to
3228 * @cputime: the cpu time spent in virtual machine since the last update
3229 * @cputime_scaled: cputime scaled by cpu frequency
3231 static void account_guest_time(struct task_struct *p, cputime_t cputime,
3232 cputime_t cputime_scaled)
3235 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
3237 tmp = cputime_to_cputime64(cputime);
3239 /* Add guest time to process. */
3240 p->utime = cputime_add(p->utime, cputime);
3241 p->utimescaled = cputime_add(p->utimescaled, cputime_scaled);
3242 account_group_user_time(p, cputime);
3243 p->gtime = cputime_add(p->gtime, cputime);
3245 /* Add guest time to cpustat. */
3246 if (TASK_NICE(p) > 0) {
3247 cpustat->nice = cputime64_add(cpustat->nice, tmp);
3248 cpustat->guest_nice = cputime64_add(cpustat->guest_nice, tmp);
3250 cpustat->user = cputime64_add(cpustat->user, tmp);
3251 cpustat->guest = cputime64_add(cpustat->guest, tmp);
3256 * Account system cpu time to a process.
3257 * @p: the process that the cpu time gets accounted to
3258 * @hardirq_offset: the offset to subtract from hardirq_count()
3259 * @cputime: the cpu time spent in kernel space since the last update
3260 * @cputime_scaled: cputime scaled by cpu frequency
3262 void account_system_time(struct task_struct *p, int hardirq_offset,
3263 cputime_t cputime, cputime_t cputime_scaled)
3265 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
3268 if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
3269 account_guest_time(p, cputime, cputime_scaled);
3273 /* Add system time to process. */
3274 p->stime = cputime_add(p->stime, cputime);
3275 p->stimescaled = cputime_add(p->stimescaled, cputime_scaled);
3276 account_group_system_time(p, cputime);
3278 /* Add system time to cpustat. */
3279 tmp = cputime_to_cputime64(cputime);
3280 if (hardirq_count() - hardirq_offset)
3281 cpustat->irq = cputime64_add(cpustat->irq, tmp);
3282 else if (softirq_count())
3283 cpustat->softirq = cputime64_add(cpustat->softirq, tmp);
3285 cpustat->system = cputime64_add(cpustat->system, tmp);
3287 cpuacct_update_stats(p, CPUACCT_STAT_SYSTEM, cputime);
3289 /* Account for system time used */
3290 acct_update_integrals(p);
3294 * Account for involuntary wait time.
3295 * @steal: the cpu time spent in involuntary wait
3297 void account_steal_time(cputime_t cputime)
3299 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
3300 cputime64_t cputime64 = cputime_to_cputime64(cputime);
3302 cpustat->steal = cputime64_add(cpustat->steal, cputime64);
3306 * Account for idle time.
3307 * @cputime: the cpu time spent in idle wait
3309 void account_idle_time(cputime_t cputime)
3311 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
3312 cputime64_t cputime64 = cputime_to_cputime64(cputime);
3313 struct rq *rq = this_rq();
3315 if (atomic_read(&rq->nr_iowait) > 0)
3316 cpustat->iowait = cputime64_add(cpustat->iowait, cputime64);
3318 cpustat->idle = cputime64_add(cpustat->idle, cputime64);
3321 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
3324 * Account a single tick of cpu time.
3325 * @p: the process that the cpu time gets accounted to
3326 * @user_tick: indicates if the tick is a user or a system tick
3328 void account_process_tick(struct task_struct *p, int user_tick)
3330 cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);
3331 struct rq *rq = this_rq();
3334 account_user_time(p, cputime_one_jiffy, one_jiffy_scaled);
3335 else if ((p != rq->idle) || (irq_count() != HARDIRQ_OFFSET))
3336 account_system_time(p, HARDIRQ_OFFSET, cputime_one_jiffy,
3339 account_idle_time(cputime_one_jiffy);
3343 * Account multiple ticks of steal time.
3344 * @p: the process from which the cpu time has been stolen
3345 * @ticks: number of stolen ticks
3347 void account_steal_ticks(unsigned long ticks)
3349 account_steal_time(jiffies_to_cputime(ticks));
3353 * Account multiple ticks of idle time.
3354 * @ticks: number of stolen ticks
3356 void account_idle_ticks(unsigned long ticks)
3358 account_idle_time(jiffies_to_cputime(ticks));
3364 * Use precise platform statistics if available:
3366 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
3367 void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
3373 void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
3375 struct task_cputime cputime;
3377 thread_group_cputime(p, &cputime);
3379 *ut = cputime.utime;
3380 *st = cputime.stime;
3384 #ifndef nsecs_to_cputime
3385 # define nsecs_to_cputime(__nsecs) nsecs_to_jiffies(__nsecs)
3388 void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
3390 cputime_t rtime, utime = p->utime, total = cputime_add(utime, p->stime);
3393 * Use CFS's precise accounting:
3395 rtime = nsecs_to_cputime(p->se.sum_exec_runtime);
3400 temp = (u64)(rtime * utime);
3401 do_div(temp, total);
3402 utime = (cputime_t)temp;
3407 * Compare with previous values, to keep monotonicity:
3409 p->prev_utime = max(p->prev_utime, utime);
3410 p->prev_stime = max(p->prev_stime, cputime_sub(rtime, p->prev_utime));
3412 *ut = p->prev_utime;
3413 *st = p->prev_stime;
3417 * Must be called with siglock held.
3419 void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
3421 struct signal_struct *sig = p->signal;
3422 struct task_cputime cputime;
3423 cputime_t rtime, utime, total;
3425 thread_group_cputime(p, &cputime);
3427 total = cputime_add(cputime.utime, cputime.stime);
3428 rtime = nsecs_to_cputime(cputime.sum_exec_runtime);
3433 temp = (u64)(rtime * cputime.utime);
3434 do_div(temp, total);
3435 utime = (cputime_t)temp;
3439 sig->prev_utime = max(sig->prev_utime, utime);
3440 sig->prev_stime = max(sig->prev_stime,
3441 cputime_sub(rtime, sig->prev_utime));
3443 *ut = sig->prev_utime;
3444 *st = sig->prev_stime;
3449 * This function gets called by the timer code, with HZ frequency.
3450 * We call it with interrupts disabled.
3452 * It also gets called by the fork code, when changing the parent's
3455 void scheduler_tick(void)
3457 int cpu = smp_processor_id();
3458 struct rq *rq = cpu_rq(cpu);
3459 struct task_struct *curr = rq->curr;
3463 raw_spin_lock(&rq->lock);
3464 update_rq_clock(rq);
3465 update_cpu_load(rq);
3466 curr->sched_class->task_tick(rq, curr, 0);
3467 raw_spin_unlock(&rq->lock);
3469 perf_event_task_tick(curr);
3472 rq->idle_at_tick = idle_cpu(cpu);
3473 trigger_load_balance(rq, cpu);
3477 notrace unsigned long get_parent_ip(unsigned long addr)
3479 if (in_lock_functions(addr)) {
3480 addr = CALLER_ADDR2;
3481 if (in_lock_functions(addr))
3482 addr = CALLER_ADDR3;
3487 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
3488 defined(CONFIG_PREEMPT_TRACER))
3490 void __kprobes add_preempt_count(int val)
3492 #ifdef CONFIG_DEBUG_PREEMPT
3496 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
3499 preempt_count() += val;
3500 #ifdef CONFIG_DEBUG_PREEMPT
3502 * Spinlock count overflowing soon?
3504 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
3507 if (preempt_count() == val)
3508 trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
3510 EXPORT_SYMBOL(add_preempt_count);
3512 void __kprobes sub_preempt_count(int val)
3514 #ifdef CONFIG_DEBUG_PREEMPT
3518 if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
3521 * Is the spinlock portion underflowing?
3523 if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
3524 !(preempt_count() & PREEMPT_MASK)))
3528 if (preempt_count() == val)
3529 trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
3530 preempt_count() -= val;
3532 EXPORT_SYMBOL(sub_preempt_count);
3537 * Print scheduling while atomic bug:
3539 static noinline void __schedule_bug(struct task_struct *prev)
3541 struct pt_regs *regs = get_irq_regs();
3543 printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
3544 prev->comm, prev->pid, preempt_count());
3546 debug_show_held_locks(prev);
3548 if (irqs_disabled())
3549 print_irqtrace_events(prev);
3558 * Various schedule()-time debugging checks and statistics:
3560 static inline void schedule_debug(struct task_struct *prev)
3563 * Test if we are atomic. Since do_exit() needs to call into
3564 * schedule() atomically, we ignore that path for now.
3565 * Otherwise, whine if we are scheduling when we should not be.
3567 if (unlikely(in_atomic_preempt_off() && !prev->exit_state))
3568 __schedule_bug(prev);
3570 profile_hit(SCHED_PROFILING, __builtin_return_address(0));
3572 schedstat_inc(this_rq(), sched_count);
3573 #ifdef CONFIG_SCHEDSTATS
3574 if (unlikely(prev->lock_depth >= 0)) {
3575 schedstat_inc(this_rq(), bkl_count);
3576 schedstat_inc(prev, sched_info.bkl_count);
3581 static void put_prev_task(struct rq *rq, struct task_struct *prev)
3584 update_rq_clock(rq);
3585 rq->skip_clock_update = 0;
3586 prev->sched_class->put_prev_task(rq, prev);
3590 * Pick up the highest-prio task:
3592 static inline struct task_struct *
3593 pick_next_task(struct rq *rq)
3595 const struct sched_class *class;
3596 struct task_struct *p;
3599 * Optimization: we know that if all tasks are in
3600 * the fair class we can call that function directly:
3602 if (likely(rq->nr_running == rq->cfs.nr_running)) {
3603 p = fair_sched_class.pick_next_task(rq);
3608 class = sched_class_highest;
3610 p = class->pick_next_task(rq);
3614 * Will never be NULL as the idle class always
3615 * returns a non-NULL p:
3617 class = class->next;
3622 * schedule() is the main scheduler function.
3624 asmlinkage void __sched schedule(void)
3626 struct task_struct *prev, *next;
3627 unsigned long *switch_count;
3633 cpu = smp_processor_id();
3637 switch_count = &prev->nivcsw;
3639 release_kernel_lock(prev);
3640 need_resched_nonpreemptible:
3642 schedule_debug(prev);
3644 if (sched_feat(HRTICK))
3647 raw_spin_lock_irq(&rq->lock);
3648 clear_tsk_need_resched(prev);
3650 if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
3651 if (unlikely(signal_pending_state(prev->state, prev)))
3652 prev->state = TASK_RUNNING;
3654 deactivate_task(rq, prev, 1);
3655 switch_count = &prev->nvcsw;
3658 pre_schedule(rq, prev);
3660 if (unlikely(!rq->nr_running))
3661 idle_balance(cpu, rq);
3663 put_prev_task(rq, prev);
3664 next = pick_next_task(rq);
3666 if (likely(prev != next)) {
3667 sched_info_switch(prev, next);
3668 perf_event_task_sched_out(prev, next);
3674 context_switch(rq, prev, next); /* unlocks the rq */
3676 * the context switch might have flipped the stack from under
3677 * us, hence refresh the local variables.
3679 cpu = smp_processor_id();
3682 raw_spin_unlock_irq(&rq->lock);
3686 if (unlikely(reacquire_kernel_lock(current) < 0)) {
3688 switch_count = &prev->nivcsw;
3689 goto need_resched_nonpreemptible;
3692 preempt_enable_no_resched();
3696 EXPORT_SYMBOL(schedule);
3698 #ifdef CONFIG_MUTEX_SPIN_ON_OWNER
3700 * Look out! "owner" is an entirely speculative pointer
3701 * access and not reliable.
3703 int mutex_spin_on_owner(struct mutex *lock, struct thread_info *owner)
3708 if (!sched_feat(OWNER_SPIN))
3711 #ifdef CONFIG_DEBUG_PAGEALLOC
3713 * Need to access the cpu field knowing that
3714 * DEBUG_PAGEALLOC could have unmapped it if
3715 * the mutex owner just released it and exited.
3717 if (probe_kernel_address(&owner->cpu, cpu))
3724 * Even if the access succeeded (likely case),
3725 * the cpu field may no longer be valid.
3727 if (cpu >= nr_cpumask_bits)
3731 * We need to validate that we can do a
3732 * get_cpu() and that we have the percpu area.
3734 if (!cpu_online(cpu))
3741 * Owner changed, break to re-assess state.
3743 if (lock->owner != owner)
3747 * Is that owner really running on that cpu?
3749 if (task_thread_info(rq->curr) != owner || need_resched())
3759 #ifdef CONFIG_PREEMPT
3761 * this is the entry point to schedule() from in-kernel preemption
3762 * off of preempt_enable. Kernel preemptions off return from interrupt
3763 * occur there and call schedule directly.
3765 asmlinkage void __sched preempt_schedule(void)
3767 struct thread_info *ti = current_thread_info();
3770 * If there is a non-zero preempt_count or interrupts are disabled,
3771 * we do not want to preempt the current task. Just return..
3773 if (likely(ti->preempt_count || irqs_disabled()))
3777 add_preempt_count(PREEMPT_ACTIVE);
3779 sub_preempt_count(PREEMPT_ACTIVE);
3782 * Check again in case we missed a preemption opportunity
3783 * between schedule and now.
3786 } while (need_resched());
3788 EXPORT_SYMBOL(preempt_schedule);
3791 * this is the entry point to schedule() from kernel preemption
3792 * off of irq context.
3793 * Note, that this is called and return with irqs disabled. This will
3794 * protect us against recursive calling from irq.
3796 asmlinkage void __sched preempt_schedule_irq(void)
3798 struct thread_info *ti = current_thread_info();
3800 /* Catch callers which need to be fixed */
3801 BUG_ON(ti->preempt_count || !irqs_disabled());
3804 add_preempt_count(PREEMPT_ACTIVE);
3807 local_irq_disable();
3808 sub_preempt_count(PREEMPT_ACTIVE);
3811 * Check again in case we missed a preemption opportunity
3812 * between schedule and now.
3815 } while (need_resched());
3818 #endif /* CONFIG_PREEMPT */
3820 int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags,
3823 return try_to_wake_up(curr->private, mode, wake_flags);
3825 EXPORT_SYMBOL(default_wake_function);
3828 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
3829 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
3830 * number) then we wake all the non-exclusive tasks and one exclusive task.
3832 * There are circumstances in which we can try to wake a task which has already
3833 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
3834 * zero in this (rare) case, and we handle it by continuing to scan the queue.
3836 static void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
3837 int nr_exclusive, int wake_flags, void *key)
3839 wait_queue_t *curr, *next;
3841 list_for_each_entry_safe(curr, next, &q->task_list, task_list) {
3842 unsigned flags = curr->flags;
3844 if (curr->func(curr, mode, wake_flags, key) &&
3845 (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive)
3851 * __wake_up - wake up threads blocked on a waitqueue.
3853 * @mode: which threads
3854 * @nr_exclusive: how many wake-one or wake-many threads to wake up
3855 * @key: is directly passed to the wakeup function
3857 * It may be assumed that this function implies a write memory barrier before
3858 * changing the task state if and only if any tasks are woken up.
3860 void __wake_up(wait_queue_head_t *q, unsigned int mode,
3861 int nr_exclusive, void *key)
3863 unsigned long flags;
3865 spin_lock_irqsave(&q->lock, flags);
3866 __wake_up_common(q, mode, nr_exclusive, 0, key);
3867 spin_unlock_irqrestore(&q->lock, flags);
3869 EXPORT_SYMBOL(__wake_up);
3872 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
3874 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode)
3876 __wake_up_common(q, mode, 1, 0, NULL);
3879 void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key)
3881 __wake_up_common(q, mode, 1, 0, key);
3885 * __wake_up_sync_key - wake up threads blocked on a waitqueue.
3887 * @mode: which threads
3888 * @nr_exclusive: how many wake-one or wake-many threads to wake up
3889 * @key: opaque value to be passed to wakeup targets
3891 * The sync wakeup differs that the waker knows that it will schedule
3892 * away soon, so while the target thread will be woken up, it will not
3893 * be migrated to another CPU - ie. the two threads are 'synchronized'
3894 * with each other. This can prevent needless bouncing between CPUs.
3896 * On UP it can prevent extra preemption.
3898 * It may be assumed that this function implies a write memory barrier before
3899 * changing the task state if and only if any tasks are woken up.
3901 void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode,
3902 int nr_exclusive, void *key)
3904 unsigned long flags;
3905 int wake_flags = WF_SYNC;
3910 if (unlikely(!nr_exclusive))
3913 spin_lock_irqsave(&q->lock, flags);
3914 __wake_up_common(q, mode, nr_exclusive, wake_flags, key);
3915 spin_unlock_irqrestore(&q->lock, flags);
3917 EXPORT_SYMBOL_GPL(__wake_up_sync_key);
3920 * __wake_up_sync - see __wake_up_sync_key()
3922 void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
3924 __wake_up_sync_key(q, mode, nr_exclusive, NULL);
3926 EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */
3929 * complete: - signals a single thread waiting on this completion
3930 * @x: holds the state of this particular completion
3932 * This will wake up a single thread waiting on this completion. Threads will be
3933 * awakened in the same order in which they were queued.
3935 * See also complete_all(), wait_for_completion() and related routines.
3937 * It may be assumed that this function implies a write memory barrier before
3938 * changing the task state if and only if any tasks are woken up.
3940 void complete(struct completion *x)
3942 unsigned long flags;
3944 spin_lock_irqsave(&x->wait.lock, flags);
3946 __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL);
3947 spin_unlock_irqrestore(&x->wait.lock, flags);
3949 EXPORT_SYMBOL(complete);
3952 * complete_all: - signals all threads waiting on this completion
3953 * @x: holds the state of this particular completion
3955 * This will wake up all threads waiting on this particular completion event.
3957 * It may be assumed that this function implies a write memory barrier before
3958 * changing the task state if and only if any tasks are woken up.
3960 void complete_all(struct completion *x)
3962 unsigned long flags;
3964 spin_lock_irqsave(&x->wait.lock, flags);
3965 x->done += UINT_MAX/2;
3966 __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL);
3967 spin_unlock_irqrestore(&x->wait.lock, flags);
3969 EXPORT_SYMBOL(complete_all);
3971 static inline long __sched
3972 do_wait_for_common(struct completion *x, long timeout, int state)
3975 DECLARE_WAITQUEUE(wait, current);
3977 wait.flags |= WQ_FLAG_EXCLUSIVE;
3978 __add_wait_queue_tail(&x->wait, &wait);
3980 if (signal_pending_state(state, current)) {
3981 timeout = -ERESTARTSYS;
3984 __set_current_state(state);
3985 spin_unlock_irq(&x->wait.lock);
3986 timeout = schedule_timeout(timeout);
3987 spin_lock_irq(&x->wait.lock);
3988 } while (!x->done && timeout);
3989 __remove_wait_queue(&x->wait, &wait);
3994 return timeout ?: 1;
3998 wait_for_common(struct completion *x, long timeout, int state)
4002 spin_lock_irq(&x->wait.lock);
4003 timeout = do_wait_for_common(x, timeout, state);
4004 spin_unlock_irq(&x->wait.lock);
4009 * wait_for_completion: - waits for completion of a task
4010 * @x: holds the state of this particular completion
4012 * This waits to be signaled for completion of a specific task. It is NOT
4013 * interruptible and there is no timeout.
4015 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
4016 * and interrupt capability. Also see complete().
4018 void __sched wait_for_completion(struct completion *x)
4020 wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE);
4022 EXPORT_SYMBOL(wait_for_completion);
4025 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
4026 * @x: holds the state of this particular completion
4027 * @timeout: timeout value in jiffies
4029 * This waits for either a completion of a specific task to be signaled or for a
4030 * specified timeout to expire. The timeout is in jiffies. It is not
4033 unsigned long __sched
4034 wait_for_completion_timeout(struct completion *x, unsigned long timeout)
4036 return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE);
4038 EXPORT_SYMBOL(wait_for_completion_timeout);
4041 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
4042 * @x: holds the state of this particular completion
4044 * This waits for completion of a specific task to be signaled. It is
4047 int __sched wait_for_completion_interruptible(struct completion *x)
4049 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE);
4050 if (t == -ERESTARTSYS)
4054 EXPORT_SYMBOL(wait_for_completion_interruptible);
4057 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
4058 * @x: holds the state of this particular completion
4059 * @timeout: timeout value in jiffies
4061 * This waits for either a completion of a specific task to be signaled or for a
4062 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
4064 unsigned long __sched
4065 wait_for_completion_interruptible_timeout(struct completion *x,
4066 unsigned long timeout)
4068 return wait_for_common(x, timeout, TASK_INTERRUPTIBLE);
4070 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout);
4073 * wait_for_completion_killable: - waits for completion of a task (killable)
4074 * @x: holds the state of this particular completion
4076 * This waits to be signaled for completion of a specific task. It can be
4077 * interrupted by a kill signal.
4079 int __sched wait_for_completion_killable(struct completion *x)
4081 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE);
4082 if (t == -ERESTARTSYS)
4086 EXPORT_SYMBOL(wait_for_completion_killable);
4089 * try_wait_for_completion - try to decrement a completion without blocking
4090 * @x: completion structure
4092 * Returns: 0 if a decrement cannot be done without blocking
4093 * 1 if a decrement succeeded.
4095 * If a completion is being used as a counting completion,
4096 * attempt to decrement the counter without blocking. This
4097 * enables us to avoid waiting if the resource the completion
4098 * is protecting is not available.
4100 bool try_wait_for_completion(struct completion *x)
4102 unsigned long flags;
4105 spin_lock_irqsave(&x->wait.lock, flags);
4110 spin_unlock_irqrestore(&x->wait.lock, flags);
4113 EXPORT_SYMBOL(try_wait_for_completion);
4116 * completion_done - Test to see if a completion has any waiters
4117 * @x: completion structure
4119 * Returns: 0 if there are waiters (wait_for_completion() in progress)
4120 * 1 if there are no waiters.
4123 bool completion_done(struct completion *x)
4125 unsigned long flags;
4128 spin_lock_irqsave(&x->wait.lock, flags);
4131 spin_unlock_irqrestore(&x->wait.lock, flags);
4134 EXPORT_SYMBOL(completion_done);
4137 sleep_on_common(wait_queue_head_t *q, int state, long timeout)
4139 unsigned long flags;
4142 init_waitqueue_entry(&wait, current);
4144 __set_current_state(state);
4146 spin_lock_irqsave(&q->lock, flags);
4147 __add_wait_queue(q, &wait);
4148 spin_unlock(&q->lock);
4149 timeout = schedule_timeout(timeout);
4150 spin_lock_irq(&q->lock);
4151 __remove_wait_queue(q, &wait);
4152 spin_unlock_irqrestore(&q->lock, flags);
4157 void __sched interruptible_sleep_on(wait_queue_head_t *q)
4159 sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
4161 EXPORT_SYMBOL(interruptible_sleep_on);
4164 interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout)
4166 return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout);
4168 EXPORT_SYMBOL(interruptible_sleep_on_timeout);
4170 void __sched sleep_on(wait_queue_head_t *q)
4172 sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
4174 EXPORT_SYMBOL(sleep_on);
4176 long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout)
4178 return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout);
4180 EXPORT_SYMBOL(sleep_on_timeout);
4182 #ifdef CONFIG_RT_MUTEXES
4185 * rt_mutex_setprio - set the current priority of a task
4187 * @prio: prio value (kernel-internal form)
4189 * This function changes the 'effective' priority of a task. It does
4190 * not touch ->normal_prio like __setscheduler().
4192 * Used by the rt_mutex code to implement priority inheritance logic.
4194 void rt_mutex_setprio(struct task_struct *p, int prio)
4196 unsigned long flags;
4197 int oldprio, on_rq, running;
4199 const struct sched_class *prev_class;
4201 BUG_ON(prio < 0 || prio > MAX_PRIO);
4203 rq = task_rq_lock(p, &flags);
4206 prev_class = p->sched_class;
4207 on_rq = p->se.on_rq;
4208 running = task_current(rq, p);
4210 dequeue_task(rq, p, 0);
4212 p->sched_class->put_prev_task(rq, p);
4215 p->sched_class = &rt_sched_class;
4217 p->sched_class = &fair_sched_class;
4222 p->sched_class->set_curr_task(rq);
4224 enqueue_task(rq, p, 0, oldprio < prio);
4226 check_class_changed(rq, p, prev_class, oldprio, running);
4228 task_rq_unlock(rq, &flags);
4233 void set_user_nice(struct task_struct *p, long nice)
4235 int old_prio, delta, on_rq;
4236 unsigned long flags;
4239 if (TASK_NICE(p) == nice || nice < -20 || nice > 19)
4242 * We have to be careful, if called from sys_setpriority(),
4243 * the task might be in the middle of scheduling on another CPU.
4245 rq = task_rq_lock(p, &flags);
4247 * The RT priorities are set via sched_setscheduler(), but we still
4248 * allow the 'normal' nice value to be set - but as expected
4249 * it wont have any effect on scheduling until the task is
4250 * SCHED_FIFO/SCHED_RR:
4252 if (task_has_rt_policy(p)) {
4253 p->static_prio = NICE_TO_PRIO(nice);
4256 on_rq = p->se.on_rq;
4258 dequeue_task(rq, p, 0);
4260 p->static_prio = NICE_TO_PRIO(nice);
4263 p->prio = effective_prio(p);
4264 delta = p->prio - old_prio;
4267 enqueue_task(rq, p, 0, false);
4269 * If the task increased its priority or is running and
4270 * lowered its priority, then reschedule its CPU:
4272 if (delta < 0 || (delta > 0 && task_running(rq, p)))
4273 resched_task(rq->curr);
4276 task_rq_unlock(rq, &flags);
4278 EXPORT_SYMBOL(set_user_nice);
4281 * can_nice - check if a task can reduce its nice value
4285 int can_nice(const struct task_struct *p, const int nice)
4287 /* convert nice value [19,-20] to rlimit style value [1,40] */
4288 int nice_rlim = 20 - nice;
4290 return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) ||
4291 capable(CAP_SYS_NICE));
4294 #ifdef __ARCH_WANT_SYS_NICE
4297 * sys_nice - change the priority of the current process.
4298 * @increment: priority increment
4300 * sys_setpriority is a more generic, but much slower function that
4301 * does similar things.
4303 SYSCALL_DEFINE1(nice, int, increment)
4308 * Setpriority might change our priority at the same moment.
4309 * We don't have to worry. Conceptually one call occurs first
4310 * and we have a single winner.
4312 if (increment < -40)
4317 nice = TASK_NICE(current) + increment;
4323 if (increment < 0 && !can_nice(current, nice))
4326 retval = security_task_setnice(current, nice);
4330 set_user_nice(current, nice);
4337 * task_prio - return the priority value of a given task.
4338 * @p: the task in question.
4340 * This is the priority value as seen by users in /proc.
4341 * RT tasks are offset by -200. Normal tasks are centered
4342 * around 0, value goes from -16 to +15.
4344 int task_prio(const struct task_struct *p)
4346 return p->prio - MAX_RT_PRIO;
4350 * task_nice - return the nice value of a given task.
4351 * @p: the task in question.
4353 int task_nice(const struct task_struct *p)
4355 return TASK_NICE(p);
4357 EXPORT_SYMBOL(task_nice);
4360 * idle_cpu - is a given cpu idle currently?
4361 * @cpu: the processor in question.
4363 int idle_cpu(int cpu)
4365 return cpu_curr(cpu) == cpu_rq(cpu)->idle;
4369 * idle_task - return the idle task for a given cpu.
4370 * @cpu: the processor in question.
4372 struct task_struct *idle_task(int cpu)
4374 return cpu_rq(cpu)->idle;
4378 * find_process_by_pid - find a process with a matching PID value.
4379 * @pid: the pid in question.
4381 static struct task_struct *find_process_by_pid(pid_t pid)
4383 return pid ? find_task_by_vpid(pid) : current;
4386 /* Actually do priority change: must hold rq lock. */
4388 __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio)
4390 BUG_ON(p->se.on_rq);
4393 p->rt_priority = prio;
4394 p->normal_prio = normal_prio(p);
4395 /* we are holding p->pi_lock already */
4396 p->prio = rt_mutex_getprio(p);
4397 if (rt_prio(p->prio))
4398 p->sched_class = &rt_sched_class;
4400 p->sched_class = &fair_sched_class;
4405 * check the target process has a UID that matches the current process's
4407 static bool check_same_owner(struct task_struct *p)
4409 const struct cred *cred = current_cred(), *pcred;
4413 pcred = __task_cred(p);
4414 match = (cred->euid == pcred->euid ||
4415 cred->euid == pcred->uid);
4420 static int __sched_setscheduler(struct task_struct *p, int policy,
4421 struct sched_param *param, bool user)
4423 int retval, oldprio, oldpolicy = -1, on_rq, running;
4424 unsigned long flags;
4425 const struct sched_class *prev_class;
4429 /* may grab non-irq protected spin_locks */
4430 BUG_ON(in_interrupt());
4432 /* double check policy once rq lock held */
4434 reset_on_fork = p->sched_reset_on_fork;
4435 policy = oldpolicy = p->policy;
4437 reset_on_fork = !!(policy & SCHED_RESET_ON_FORK);
4438 policy &= ~SCHED_RESET_ON_FORK;
4440 if (policy != SCHED_FIFO && policy != SCHED_RR &&
4441 policy != SCHED_NORMAL && policy != SCHED_BATCH &&
4442 policy != SCHED_IDLE)
4447 * Valid priorities for SCHED_FIFO and SCHED_RR are
4448 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
4449 * SCHED_BATCH and SCHED_IDLE is 0.
4451 if (param->sched_priority < 0 ||
4452 (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) ||
4453 (!p->mm && param->sched_priority > MAX_RT_PRIO-1))
4455 if (rt_policy(policy) != (param->sched_priority != 0))
4459 * Allow unprivileged RT tasks to decrease priority:
4461 if (user && !capable(CAP_SYS_NICE)) {
4462 if (rt_policy(policy)) {
4463 unsigned long rlim_rtprio;
4465 if (!lock_task_sighand(p, &flags))
4467 rlim_rtprio = task_rlimit(p, RLIMIT_RTPRIO);
4468 unlock_task_sighand(p, &flags);
4470 /* can't set/change the rt policy */
4471 if (policy != p->policy && !rlim_rtprio)
4474 /* can't increase priority */
4475 if (param->sched_priority > p->rt_priority &&
4476 param->sched_priority > rlim_rtprio)
4480 * Like positive nice levels, dont allow tasks to
4481 * move out of SCHED_IDLE either:
4483 if (p->policy == SCHED_IDLE && policy != SCHED_IDLE)
4486 /* can't change other user's priorities */
4487 if (!check_same_owner(p))
4490 /* Normal users shall not reset the sched_reset_on_fork flag */
4491 if (p->sched_reset_on_fork && !reset_on_fork)
4496 #ifdef CONFIG_RT_GROUP_SCHED
4498 * Do not allow realtime tasks into groups that have no runtime
4501 if (rt_bandwidth_enabled() && rt_policy(policy) &&
4502 task_group(p)->rt_bandwidth.rt_runtime == 0)
4506 retval = security_task_setscheduler(p, policy, param);
4512 * make sure no PI-waiters arrive (or leave) while we are
4513 * changing the priority of the task:
4515 raw_spin_lock_irqsave(&p->pi_lock, flags);
4517 * To be able to change p->policy safely, the apropriate
4518 * runqueue lock must be held.
4520 rq = __task_rq_lock(p);
4521 /* recheck policy now with rq lock held */
4522 if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
4523 policy = oldpolicy = -1;
4524 __task_rq_unlock(rq);
4525 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
4528 on_rq = p->se.on_rq;
4529 running = task_current(rq, p);
4531 deactivate_task(rq, p, 0);
4533 p->sched_class->put_prev_task(rq, p);
4535 p->sched_reset_on_fork = reset_on_fork;
4538 prev_class = p->sched_class;
4539 __setscheduler(rq, p, policy, param->sched_priority);
4542 p->sched_class->set_curr_task(rq);
4544 activate_task(rq, p, 0);
4546 check_class_changed(rq, p, prev_class, oldprio, running);
4548 __task_rq_unlock(rq);
4549 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
4551 rt_mutex_adjust_pi(p);
4557 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
4558 * @p: the task in question.
4559 * @policy: new policy.
4560 * @param: structure containing the new RT priority.
4562 * NOTE that the task may be already dead.
4564 int sched_setscheduler(struct task_struct *p, int policy,
4565 struct sched_param *param)
4567 return __sched_setscheduler(p, policy, param, true);
4569 EXPORT_SYMBOL_GPL(sched_setscheduler);
4572 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
4573 * @p: the task in question.
4574 * @policy: new policy.
4575 * @param: structure containing the new RT priority.
4577 * Just like sched_setscheduler, only don't bother checking if the
4578 * current context has permission. For example, this is needed in
4579 * stop_machine(): we create temporary high priority worker threads,
4580 * but our caller might not have that capability.
4582 int sched_setscheduler_nocheck(struct task_struct *p, int policy,
4583 struct sched_param *param)
4585 return __sched_setscheduler(p, policy, param, false);
4589 do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
4591 struct sched_param lparam;
4592 struct task_struct *p;
4595 if (!param || pid < 0)
4597 if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
4602 p = find_process_by_pid(pid);
4604 retval = sched_setscheduler(p, policy, &lparam);
4611 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
4612 * @pid: the pid in question.
4613 * @policy: new policy.
4614 * @param: structure containing the new RT priority.
4616 SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy,
4617 struct sched_param __user *, param)
4619 /* negative values for policy are not valid */
4623 return do_sched_setscheduler(pid, policy, param);
4627 * sys_sched_setparam - set/change the RT priority of a thread
4628 * @pid: the pid in question.
4629 * @param: structure containing the new RT priority.
4631 SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param)
4633 return do_sched_setscheduler(pid, -1, param);
4637 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
4638 * @pid: the pid in question.
4640 SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid)
4642 struct task_struct *p;
4650 p = find_process_by_pid(pid);
4652 retval = security_task_getscheduler(p);
4655 | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0);
4662 * sys_sched_getparam - get the RT priority of a thread
4663 * @pid: the pid in question.
4664 * @param: structure containing the RT priority.
4666 SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param)
4668 struct sched_param lp;
4669 struct task_struct *p;
4672 if (!param || pid < 0)
4676 p = find_process_by_pid(pid);
4681 retval = security_task_getscheduler(p);
4685 lp.sched_priority = p->rt_priority;
4689 * This one might sleep, we cannot do it with a spinlock held ...
4691 retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;
4700 long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
4702 cpumask_var_t cpus_allowed, new_mask;
4703 struct task_struct *p;
4709 p = find_process_by_pid(pid);
4716 /* Prevent p going away */
4720 if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) {
4724 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
4726 goto out_free_cpus_allowed;
4729 if (!check_same_owner(p) && !capable(CAP_SYS_NICE))
4732 retval = security_task_setscheduler(p, 0, NULL);
4736 cpuset_cpus_allowed(p, cpus_allowed);
4737 cpumask_and(new_mask, in_mask, cpus_allowed);
4739 retval = set_cpus_allowed_ptr(p, new_mask);
4742 cpuset_cpus_allowed(p, cpus_allowed);
4743 if (!cpumask_subset(new_mask, cpus_allowed)) {
4745 * We must have raced with a concurrent cpuset
4746 * update. Just reset the cpus_allowed to the
4747 * cpuset's cpus_allowed
4749 cpumask_copy(new_mask, cpus_allowed);
4754 free_cpumask_var(new_mask);
4755 out_free_cpus_allowed:
4756 free_cpumask_var(cpus_allowed);
4763 static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
4764 struct cpumask *new_mask)
4766 if (len < cpumask_size())
4767 cpumask_clear(new_mask);
4768 else if (len > cpumask_size())
4769 len = cpumask_size();
4771 return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
4775 * sys_sched_setaffinity - set the cpu affinity of a process
4776 * @pid: pid of the process
4777 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4778 * @user_mask_ptr: user-space pointer to the new cpu mask
4780 SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len,
4781 unsigned long __user *, user_mask_ptr)
4783 cpumask_var_t new_mask;
4786 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
4789 retval = get_user_cpu_mask(user_mask_ptr, len, new_mask);
4791 retval = sched_setaffinity(pid, new_mask);
4792 free_cpumask_var(new_mask);
4796 long sched_getaffinity(pid_t pid, struct cpumask *mask)
4798 struct task_struct *p;
4799 unsigned long flags;
4807 p = find_process_by_pid(pid);
4811 retval = security_task_getscheduler(p);
4815 rq = task_rq_lock(p, &flags);
4816 cpumask_and(mask, &p->cpus_allowed, cpu_online_mask);
4817 task_rq_unlock(rq, &flags);
4827 * sys_sched_getaffinity - get the cpu affinity of a process
4828 * @pid: pid of the process
4829 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4830 * @user_mask_ptr: user-space pointer to hold the current cpu mask
4832 SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
4833 unsigned long __user *, user_mask_ptr)
4838 if (len < nr_cpu_ids)
4840 if (len & (sizeof(unsigned long)-1))
4843 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
4846 ret = sched_getaffinity(pid, mask);
4848 size_t retlen = min_t(size_t, len, cpumask_size());
4850 if (copy_to_user(user_mask_ptr, mask, retlen))
4855 free_cpumask_var(mask);
4861 * sys_sched_yield - yield the current processor to other threads.
4863 * This function yields the current CPU to other tasks. If there are no
4864 * other threads running on this CPU then this function will return.
4866 SYSCALL_DEFINE0(sched_yield)
4868 struct rq *rq = this_rq_lock();
4870 schedstat_inc(rq, yld_count);
4871 current->sched_class->yield_task(rq);
4874 * Since we are going to call schedule() anyway, there's
4875 * no need to preempt or enable interrupts:
4877 __release(rq->lock);
4878 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
4879 do_raw_spin_unlock(&rq->lock);
4880 preempt_enable_no_resched();
4887 static inline int should_resched(void)
4889 return need_resched() && !(preempt_count() & PREEMPT_ACTIVE);
4892 static void __cond_resched(void)
4894 add_preempt_count(PREEMPT_ACTIVE);
4896 sub_preempt_count(PREEMPT_ACTIVE);
4899 int __sched _cond_resched(void)
4901 if (should_resched()) {
4907 EXPORT_SYMBOL(_cond_resched);
4910 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
4911 * call schedule, and on return reacquire the lock.
4913 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
4914 * operations here to prevent schedule() from being called twice (once via
4915 * spin_unlock(), once by hand).
4917 int __cond_resched_lock(spinlock_t *lock)
4919 int resched = should_resched();
4922 lockdep_assert_held(lock);
4924 if (spin_needbreak(lock) || resched) {
4935 EXPORT_SYMBOL(__cond_resched_lock);
4937 int __sched __cond_resched_softirq(void)
4939 BUG_ON(!in_softirq());
4941 if (should_resched()) {
4949 EXPORT_SYMBOL(__cond_resched_softirq);
4952 * yield - yield the current processor to other threads.
4954 * This is a shortcut for kernel-space yielding - it marks the
4955 * thread runnable and calls sys_sched_yield().
4957 void __sched yield(void)
4959 set_current_state(TASK_RUNNING);
4962 EXPORT_SYMBOL(yield);
4965 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
4966 * that process accounting knows that this is a task in IO wait state.
4968 void __sched io_schedule(void)
4970 struct rq *rq = raw_rq();
4972 delayacct_blkio_start();
4973 atomic_inc(&rq->nr_iowait);
4974 current->in_iowait = 1;
4976 current->in_iowait = 0;
4977 atomic_dec(&rq->nr_iowait);
4978 delayacct_blkio_end();
4980 EXPORT_SYMBOL(io_schedule);
4982 long __sched io_schedule_timeout(long timeout)
4984 struct rq *rq = raw_rq();
4987 delayacct_blkio_start();
4988 atomic_inc(&rq->nr_iowait);
4989 current->in_iowait = 1;
4990 ret = schedule_timeout(timeout);
4991 current->in_iowait = 0;
4992 atomic_dec(&rq->nr_iowait);
4993 delayacct_blkio_end();
4998 * sys_sched_get_priority_max - return maximum RT priority.
4999 * @policy: scheduling class.
5001 * this syscall returns the maximum rt_priority that can be used
5002 * by a given scheduling class.
5004 SYSCALL_DEFINE1(sched_get_priority_max, int, policy)
5011 ret = MAX_USER_RT_PRIO-1;
5023 * sys_sched_get_priority_min - return minimum RT priority.
5024 * @policy: scheduling class.
5026 * this syscall returns the minimum rt_priority that can be used
5027 * by a given scheduling class.
5029 SYSCALL_DEFINE1(sched_get_priority_min, int, policy)
5047 * sys_sched_rr_get_interval - return the default timeslice of a process.
5048 * @pid: pid of the process.
5049 * @interval: userspace pointer to the timeslice value.
5051 * this syscall writes the default timeslice value of a given process
5052 * into the user-space timespec buffer. A value of '0' means infinity.
5054 SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid,
5055 struct timespec __user *, interval)
5057 struct task_struct *p;
5058 unsigned int time_slice;
5059 unsigned long flags;
5069 p = find_process_by_pid(pid);
5073 retval = security_task_getscheduler(p);
5077 rq = task_rq_lock(p, &flags);
5078 time_slice = p->sched_class->get_rr_interval(rq, p);
5079 task_rq_unlock(rq, &flags);
5082 jiffies_to_timespec(time_slice, &t);
5083 retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;
5091 static const char stat_nam[] = TASK_STATE_TO_CHAR_STR;
5093 void sched_show_task(struct task_struct *p)
5095 unsigned long free = 0;
5098 state = p->state ? __ffs(p->state) + 1 : 0;
5099 printk(KERN_INFO "%-13.13s %c", p->comm,
5100 state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?');
5101 #if BITS_PER_LONG == 32
5102 if (state == TASK_RUNNING)
5103 printk(KERN_CONT " running ");
5105 printk(KERN_CONT " %08lx ", thread_saved_pc(p));
5107 if (state == TASK_RUNNING)
5108 printk(KERN_CONT " running task ");
5110 printk(KERN_CONT " %016lx ", thread_saved_pc(p));
5112 #ifdef CONFIG_DEBUG_STACK_USAGE
5113 free = stack_not_used(p);
5115 printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free,
5116 task_pid_nr(p), task_pid_nr(p->real_parent),
5117 (unsigned long)task_thread_info(p)->flags);
5119 show_stack(p, NULL);
5122 void show_state_filter(unsigned long state_filter)
5124 struct task_struct *g, *p;
5126 #if BITS_PER_LONG == 32
5128 " task PC stack pid father\n");
5131 " task PC stack pid father\n");
5133 read_lock(&tasklist_lock);
5134 do_each_thread(g, p) {
5136 * reset the NMI-timeout, listing all files on a slow
5137 * console might take alot of time:
5139 touch_nmi_watchdog();
5140 if (!state_filter || (p->state & state_filter))
5142 } while_each_thread(g, p);
5144 touch_all_softlockup_watchdogs();
5146 #ifdef CONFIG_SCHED_DEBUG
5147 sysrq_sched_debug_show();
5149 read_unlock(&tasklist_lock);
5151 * Only show locks if all tasks are dumped:
5154 debug_show_all_locks();
5157 void __cpuinit init_idle_bootup_task(struct task_struct *idle)
5159 idle->sched_class = &idle_sched_class;
5163 * init_idle - set up an idle thread for a given CPU
5164 * @idle: task in question
5165 * @cpu: cpu the idle task belongs to
5167 * NOTE: this function does not set the idle thread's NEED_RESCHED
5168 * flag, to make booting more robust.
5170 void __cpuinit init_idle(struct task_struct *idle, int cpu)
5172 struct rq *rq = cpu_rq(cpu);
5173 unsigned long flags;
5175 raw_spin_lock_irqsave(&rq->lock, flags);
5178 idle->state = TASK_RUNNING;
5179 idle->se.exec_start = sched_clock();
5181 cpumask_copy(&idle->cpus_allowed, cpumask_of(cpu));
5182 __set_task_cpu(idle, cpu);
5184 rq->curr = rq->idle = idle;
5185 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
5188 raw_spin_unlock_irqrestore(&rq->lock, flags);
5190 /* Set the preempt count _outside_ the spinlocks! */
5191 #if defined(CONFIG_PREEMPT)
5192 task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0);
5194 task_thread_info(idle)->preempt_count = 0;
5197 * The idle tasks have their own, simple scheduling class:
5199 idle->sched_class = &idle_sched_class;
5200 ftrace_graph_init_task(idle);
5204 * In a system that switches off the HZ timer nohz_cpu_mask
5205 * indicates which cpus entered this state. This is used
5206 * in the rcu update to wait only for active cpus. For system
5207 * which do not switch off the HZ timer nohz_cpu_mask should
5208 * always be CPU_BITS_NONE.
5210 cpumask_var_t nohz_cpu_mask;
5213 * Increase the granularity value when there are more CPUs,
5214 * because with more CPUs the 'effective latency' as visible
5215 * to users decreases. But the relationship is not linear,
5216 * so pick a second-best guess by going with the log2 of the
5219 * This idea comes from the SD scheduler of Con Kolivas:
5221 static int get_update_sysctl_factor(void)
5223 unsigned int cpus = min_t(int, num_online_cpus(), 8);
5224 unsigned int factor;
5226 switch (sysctl_sched_tunable_scaling) {
5227 case SCHED_TUNABLESCALING_NONE:
5230 case SCHED_TUNABLESCALING_LINEAR:
5233 case SCHED_TUNABLESCALING_LOG:
5235 factor = 1 + ilog2(cpus);
5242 static void update_sysctl(void)
5244 unsigned int factor = get_update_sysctl_factor();
5246 #define SET_SYSCTL(name) \
5247 (sysctl_##name = (factor) * normalized_sysctl_##name)
5248 SET_SYSCTL(sched_min_granularity);
5249 SET_SYSCTL(sched_latency);
5250 SET_SYSCTL(sched_wakeup_granularity);
5251 SET_SYSCTL(sched_shares_ratelimit);
5255 static inline void sched_init_granularity(void)
5262 * This is how migration works:
5264 * 1) we queue a struct migration_req structure in the source CPU's
5265 * runqueue and wake up that CPU's migration thread.
5266 * 2) we down() the locked semaphore => thread blocks.
5267 * 3) migration thread wakes up (implicitly it forces the migrated
5268 * thread off the CPU)
5269 * 4) it gets the migration request and checks whether the migrated
5270 * task is still in the wrong runqueue.
5271 * 5) if it's in the wrong runqueue then the migration thread removes
5272 * it and puts it into the right queue.
5273 * 6) migration thread up()s the semaphore.
5274 * 7) we wake up and the migration is done.
5278 * Change a given task's CPU affinity. Migrate the thread to a
5279 * proper CPU and schedule it away if the CPU it's executing on
5280 * is removed from the allowed bitmask.
5282 * NOTE: the caller must have a valid reference to the task, the
5283 * task must not exit() & deallocate itself prematurely. The
5284 * call is not atomic; no spinlocks may be held.
5286 int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
5288 struct migration_req req;
5289 unsigned long flags;
5293 rq = task_rq_lock(p, &flags);
5295 if (!cpumask_intersects(new_mask, cpu_active_mask)) {
5300 if (unlikely((p->flags & PF_THREAD_BOUND) && p != current &&
5301 !cpumask_equal(&p->cpus_allowed, new_mask))) {
5306 if (p->sched_class->set_cpus_allowed)
5307 p->sched_class->set_cpus_allowed(p, new_mask);
5309 cpumask_copy(&p->cpus_allowed, new_mask);
5310 p->rt.nr_cpus_allowed = cpumask_weight(new_mask);
5313 /* Can the task run on the task's current CPU? If so, we're done */
5314 if (cpumask_test_cpu(task_cpu(p), new_mask))
5317 if (migrate_task(p, cpumask_any_and(cpu_active_mask, new_mask), &req)) {
5318 /* Need help from migration thread: drop lock and wait. */
5319 struct task_struct *mt = rq->migration_thread;
5321 get_task_struct(mt);
5322 task_rq_unlock(rq, &flags);
5323 wake_up_process(rq->migration_thread);
5324 put_task_struct(mt);
5325 wait_for_completion(&req.done);
5326 tlb_migrate_finish(p->mm);
5330 task_rq_unlock(rq, &flags);
5334 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
5337 * Move (not current) task off this cpu, onto dest cpu. We're doing
5338 * this because either it can't run here any more (set_cpus_allowed()
5339 * away from this CPU, or CPU going down), or because we're
5340 * attempting to rebalance this task on exec (sched_exec).
5342 * So we race with normal scheduler movements, but that's OK, as long
5343 * as the task is no longer on this CPU.
5345 * Returns non-zero if task was successfully migrated.
5347 static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
5349 struct rq *rq_dest, *rq_src;
5352 if (unlikely(!cpu_active(dest_cpu)))
5355 rq_src = cpu_rq(src_cpu);
5356 rq_dest = cpu_rq(dest_cpu);
5358 double_rq_lock(rq_src, rq_dest);
5359 /* Already moved. */
5360 if (task_cpu(p) != src_cpu)
5362 /* Affinity changed (again). */
5363 if (!cpumask_test_cpu(dest_cpu, &p->cpus_allowed))
5367 * If we're not on a rq, the next wake-up will ensure we're
5371 deactivate_task(rq_src, p, 0);
5372 set_task_cpu(p, dest_cpu);
5373 activate_task(rq_dest, p, 0);
5374 check_preempt_curr(rq_dest, p, 0);
5379 double_rq_unlock(rq_src, rq_dest);
5383 #define RCU_MIGRATION_IDLE 0
5384 #define RCU_MIGRATION_NEED_QS 1
5385 #define RCU_MIGRATION_GOT_QS 2
5386 #define RCU_MIGRATION_MUST_SYNC 3
5389 * migration_thread - this is a highprio system thread that performs
5390 * thread migration by bumping thread off CPU then 'pushing' onto
5393 static int migration_thread(void *data)
5396 int cpu = (long)data;
5400 BUG_ON(rq->migration_thread != current);
5402 set_current_state(TASK_INTERRUPTIBLE);
5403 while (!kthread_should_stop()) {
5404 struct migration_req *req;
5405 struct list_head *head;
5407 raw_spin_lock_irq(&rq->lock);
5409 if (cpu_is_offline(cpu)) {
5410 raw_spin_unlock_irq(&rq->lock);
5414 if (rq->active_balance) {
5415 active_load_balance(rq, cpu);
5416 rq->active_balance = 0;
5419 head = &rq->migration_queue;
5421 if (list_empty(head)) {
5422 raw_spin_unlock_irq(&rq->lock);
5424 set_current_state(TASK_INTERRUPTIBLE);
5427 req = list_entry(head->next, struct migration_req, list);
5428 list_del_init(head->next);
5430 if (req->task != NULL) {
5431 raw_spin_unlock(&rq->lock);
5432 __migrate_task(req->task, cpu, req->dest_cpu);
5433 } else if (likely(cpu == (badcpu = smp_processor_id()))) {
5434 req->dest_cpu = RCU_MIGRATION_GOT_QS;
5435 raw_spin_unlock(&rq->lock);
5437 req->dest_cpu = RCU_MIGRATION_MUST_SYNC;
5438 raw_spin_unlock(&rq->lock);
5439 WARN_ONCE(1, "migration_thread() on CPU %d, expected %d\n", badcpu, cpu);
5443 complete(&req->done);
5445 __set_current_state(TASK_RUNNING);
5450 #ifdef CONFIG_HOTPLUG_CPU
5452 * Figure out where task on dead CPU should go, use force if necessary.
5454 static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p)
5456 struct rq *rq = cpu_rq(dead_cpu);
5457 int needs_cpu, uninitialized_var(dest_cpu);
5458 unsigned long flags;
5460 local_irq_save(flags);
5462 raw_spin_lock(&rq->lock);
5463 needs_cpu = (task_cpu(p) == dead_cpu) && (p->state != TASK_WAKING);
5465 dest_cpu = select_fallback_rq(dead_cpu, p);
5466 raw_spin_unlock(&rq->lock);
5468 * It can only fail if we race with set_cpus_allowed(),
5469 * in the racer should migrate the task anyway.
5472 __migrate_task(p, dead_cpu, dest_cpu);
5473 local_irq_restore(flags);
5477 * While a dead CPU has no uninterruptible tasks queued at this point,
5478 * it might still have a nonzero ->nr_uninterruptible counter, because
5479 * for performance reasons the counter is not stricly tracking tasks to
5480 * their home CPUs. So we just add the counter to another CPU's counter,
5481 * to keep the global sum constant after CPU-down:
5483 static void migrate_nr_uninterruptible(struct rq *rq_src)
5485 struct rq *rq_dest = cpu_rq(cpumask_any(cpu_active_mask));
5486 unsigned long flags;
5488 local_irq_save(flags);
5489 double_rq_lock(rq_src, rq_dest);
5490 rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible;
5491 rq_src->nr_uninterruptible = 0;
5492 double_rq_unlock(rq_src, rq_dest);
5493 local_irq_restore(flags);
5496 /* Run through task list and migrate tasks from the dead cpu. */
5497 static void migrate_live_tasks(int src_cpu)
5499 struct task_struct *p, *t;
5501 read_lock(&tasklist_lock);
5503 do_each_thread(t, p) {
5507 if (task_cpu(p) == src_cpu)
5508 move_task_off_dead_cpu(src_cpu, p);
5509 } while_each_thread(t, p);
5511 read_unlock(&tasklist_lock);
5515 * Schedules idle task to be the next runnable task on current CPU.
5516 * It does so by boosting its priority to highest possible.
5517 * Used by CPU offline code.
5519 void sched_idle_next(void)
5521 int this_cpu = smp_processor_id();
5522 struct rq *rq = cpu_rq(this_cpu);
5523 struct task_struct *p = rq->idle;
5524 unsigned long flags;
5526 /* cpu has to be offline */
5527 BUG_ON(cpu_online(this_cpu));
5530 * Strictly not necessary since rest of the CPUs are stopped by now
5531 * and interrupts disabled on the current cpu.
5533 raw_spin_lock_irqsave(&rq->lock, flags);
5535 __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
5537 activate_task(rq, p, 0);
5539 raw_spin_unlock_irqrestore(&rq->lock, flags);
5543 * Ensures that the idle task is using init_mm right before its cpu goes
5546 void idle_task_exit(void)
5548 struct mm_struct *mm = current->active_mm;
5550 BUG_ON(cpu_online(smp_processor_id()));
5553 switch_mm(mm, &init_mm, current);
5557 /* called under rq->lock with disabled interrupts */
5558 static void migrate_dead(unsigned int dead_cpu, struct task_struct *p)
5560 struct rq *rq = cpu_rq(dead_cpu);
5562 /* Must be exiting, otherwise would be on tasklist. */
5563 BUG_ON(!p->exit_state);
5565 /* Cannot have done final schedule yet: would have vanished. */
5566 BUG_ON(p->state == TASK_DEAD);
5571 * Drop lock around migration; if someone else moves it,
5572 * that's OK. No task can be added to this CPU, so iteration is
5575 raw_spin_unlock_irq(&rq->lock);
5576 move_task_off_dead_cpu(dead_cpu, p);
5577 raw_spin_lock_irq(&rq->lock);
5582 /* release_task() removes task from tasklist, so we won't find dead tasks. */
5583 static void migrate_dead_tasks(unsigned int dead_cpu)
5585 struct rq *rq = cpu_rq(dead_cpu);
5586 struct task_struct *next;
5589 if (!rq->nr_running)
5591 next = pick_next_task(rq);
5594 next->sched_class->put_prev_task(rq, next);
5595 migrate_dead(dead_cpu, next);
5601 * remove the tasks which were accounted by rq from calc_load_tasks.
5603 static void calc_global_load_remove(struct rq *rq)
5605 atomic_long_sub(rq->calc_load_active, &calc_load_tasks);
5606 rq->calc_load_active = 0;
5608 #endif /* CONFIG_HOTPLUG_CPU */
5610 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
5612 static struct ctl_table sd_ctl_dir[] = {
5614 .procname = "sched_domain",
5620 static struct ctl_table sd_ctl_root[] = {
5622 .procname = "kernel",
5624 .child = sd_ctl_dir,
5629 static struct ctl_table *sd_alloc_ctl_entry(int n)
5631 struct ctl_table *entry =
5632 kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL);
5637 static void sd_free_ctl_entry(struct ctl_table **tablep)
5639 struct ctl_table *entry;
5642 * In the intermediate directories, both the child directory and
5643 * procname are dynamically allocated and could fail but the mode
5644 * will always be set. In the lowest directory the names are
5645 * static strings and all have proc handlers.
5647 for (entry = *tablep; entry->mode; entry++) {
5649 sd_free_ctl_entry(&entry->child);
5650 if (entry->proc_handler == NULL)
5651 kfree(entry->procname);
5659 set_table_entry(struct ctl_table *entry,
5660 const char *procname, void *data, int maxlen,
5661 mode_t mode, proc_handler *proc_handler)
5663 entry->procname = procname;
5665 entry->maxlen = maxlen;
5667 entry->proc_handler = proc_handler;
5670 static struct ctl_table *
5671 sd_alloc_ctl_domain_table(struct sched_domain *sd)
5673 struct ctl_table *table = sd_alloc_ctl_entry(13);
5678 set_table_entry(&table[0], "min_interval", &sd->min_interval,
5679 sizeof(long), 0644, proc_doulongvec_minmax);
5680 set_table_entry(&table[1], "max_interval", &sd->max_interval,
5681 sizeof(long), 0644, proc_doulongvec_minmax);
5682 set_table_entry(&table[2], "busy_idx", &sd->busy_idx,
5683 sizeof(int), 0644, proc_dointvec_minmax);
5684 set_table_entry(&table[3], "idle_idx", &sd->idle_idx,
5685 sizeof(int), 0644, proc_dointvec_minmax);
5686 set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx,
5687 sizeof(int), 0644, proc_dointvec_minmax);
5688 set_table_entry(&table[5], "wake_idx", &sd->wake_idx,
5689 sizeof(int), 0644, proc_dointvec_minmax);
5690 set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx,
5691 sizeof(int), 0644, proc_dointvec_minmax);
5692 set_table_entry(&table[7], "busy_factor", &sd->busy_factor,
5693 sizeof(int), 0644, proc_dointvec_minmax);
5694 set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct,
5695 sizeof(int), 0644, proc_dointvec_minmax);
5696 set_table_entry(&table[9], "cache_nice_tries",
5697 &sd->cache_nice_tries,
5698 sizeof(int), 0644, proc_dointvec_minmax);
5699 set_table_entry(&table[10], "flags", &sd->flags,
5700 sizeof(int), 0644, proc_dointvec_minmax);
5701 set_table_entry(&table[11], "name", sd->name,
5702 CORENAME_MAX_SIZE, 0444, proc_dostring);
5703 /* &table[12] is terminator */
5708 static ctl_table *sd_alloc_ctl_cpu_table(int cpu)
5710 struct ctl_table *entry, *table;
5711 struct sched_domain *sd;
5712 int domain_num = 0, i;
5715 for_each_domain(cpu, sd)
5717 entry = table = sd_alloc_ctl_entry(domain_num + 1);
5722 for_each_domain(cpu, sd) {
5723 snprintf(buf, 32, "domain%d", i);
5724 entry->procname = kstrdup(buf, GFP_KERNEL);
5726 entry->child = sd_alloc_ctl_domain_table(sd);
5733 static struct ctl_table_header *sd_sysctl_header;
5734 static void register_sched_domain_sysctl(void)
5736 int i, cpu_num = num_possible_cpus();
5737 struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1);
5740 WARN_ON(sd_ctl_dir[0].child);
5741 sd_ctl_dir[0].child = entry;
5746 for_each_possible_cpu(i) {
5747 snprintf(buf, 32, "cpu%d", i);
5748 entry->procname = kstrdup(buf, GFP_KERNEL);
5750 entry->child = sd_alloc_ctl_cpu_table(i);
5754 WARN_ON(sd_sysctl_header);
5755 sd_sysctl_header = register_sysctl_table(sd_ctl_root);
5758 /* may be called multiple times per register */
5759 static void unregister_sched_domain_sysctl(void)
5761 if (sd_sysctl_header)
5762 unregister_sysctl_table(sd_sysctl_header);
5763 sd_sysctl_header = NULL;
5764 if (sd_ctl_dir[0].child)
5765 sd_free_ctl_entry(&sd_ctl_dir[0].child);
5768 static void register_sched_domain_sysctl(void)
5771 static void unregister_sched_domain_sysctl(void)
5776 static void set_rq_online(struct rq *rq)
5779 const struct sched_class *class;
5781 cpumask_set_cpu(rq->cpu, rq->rd->online);
5784 for_each_class(class) {
5785 if (class->rq_online)
5786 class->rq_online(rq);
5791 static void set_rq_offline(struct rq *rq)
5794 const struct sched_class *class;
5796 for_each_class(class) {
5797 if (class->rq_offline)
5798 class->rq_offline(rq);
5801 cpumask_clear_cpu(rq->cpu, rq->rd->online);
5807 * migration_call - callback that gets triggered when a CPU is added.
5808 * Here we can start up the necessary migration thread for the new CPU.
5810 static int __cpuinit
5811 migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
5813 struct task_struct *p;
5814 int cpu = (long)hcpu;
5815 unsigned long flags;
5820 case CPU_UP_PREPARE:
5821 case CPU_UP_PREPARE_FROZEN:
5822 p = kthread_create(migration_thread, hcpu, "migration/%d", cpu);
5825 kthread_bind(p, cpu);
5826 /* Must be high prio: stop_machine expects to yield to it. */
5827 rq = task_rq_lock(p, &flags);
5828 __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
5829 task_rq_unlock(rq, &flags);
5831 cpu_rq(cpu)->migration_thread = p;
5832 rq->calc_load_update = calc_load_update;
5836 case CPU_ONLINE_FROZEN:
5837 /* Strictly unnecessary, as first user will wake it. */
5838 wake_up_process(cpu_rq(cpu)->migration_thread);
5840 /* Update our root-domain */
5842 raw_spin_lock_irqsave(&rq->lock, flags);
5844 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
5848 raw_spin_unlock_irqrestore(&rq->lock, flags);
5851 #ifdef CONFIG_HOTPLUG_CPU
5852 case CPU_UP_CANCELED:
5853 case CPU_UP_CANCELED_FROZEN:
5854 if (!cpu_rq(cpu)->migration_thread)
5856 /* Unbind it from offline cpu so it can run. Fall thru. */
5857 kthread_bind(cpu_rq(cpu)->migration_thread,
5858 cpumask_any(cpu_online_mask));
5859 kthread_stop(cpu_rq(cpu)->migration_thread);
5860 put_task_struct(cpu_rq(cpu)->migration_thread);
5861 cpu_rq(cpu)->migration_thread = NULL;
5865 case CPU_DEAD_FROZEN:
5866 migrate_live_tasks(cpu);
5868 kthread_stop(rq->migration_thread);
5869 put_task_struct(rq->migration_thread);
5870 rq->migration_thread = NULL;
5871 /* Idle task back to normal (off runqueue, low prio) */
5872 raw_spin_lock_irq(&rq->lock);
5873 deactivate_task(rq, rq->idle, 0);
5874 __setscheduler(rq, rq->idle, SCHED_NORMAL, 0);
5875 rq->idle->sched_class = &idle_sched_class;
5876 migrate_dead_tasks(cpu);
5877 raw_spin_unlock_irq(&rq->lock);
5878 migrate_nr_uninterruptible(rq);
5879 BUG_ON(rq->nr_running != 0);
5880 calc_global_load_remove(rq);
5882 * No need to migrate the tasks: it was best-effort if
5883 * they didn't take sched_hotcpu_mutex. Just wake up
5886 raw_spin_lock_irq(&rq->lock);
5887 while (!list_empty(&rq->migration_queue)) {
5888 struct migration_req *req;
5890 req = list_entry(rq->migration_queue.next,
5891 struct migration_req, list);
5892 list_del_init(&req->list);
5893 raw_spin_unlock_irq(&rq->lock);
5894 complete(&req->done);
5895 raw_spin_lock_irq(&rq->lock);
5897 raw_spin_unlock_irq(&rq->lock);
5901 case CPU_DYING_FROZEN:
5902 /* Update our root-domain */
5904 raw_spin_lock_irqsave(&rq->lock, flags);
5906 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
5909 raw_spin_unlock_irqrestore(&rq->lock, flags);
5917 * Register at high priority so that task migration (migrate_all_tasks)
5918 * happens before everything else. This has to be lower priority than
5919 * the notifier in the perf_event subsystem, though.
5921 static struct notifier_block __cpuinitdata migration_notifier = {
5922 .notifier_call = migration_call,
5926 static int __init migration_init(void)
5928 void *cpu = (void *)(long)smp_processor_id();
5931 /* Start one for the boot CPU: */
5932 err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
5933 BUG_ON(err == NOTIFY_BAD);
5934 migration_call(&migration_notifier, CPU_ONLINE, cpu);
5935 register_cpu_notifier(&migration_notifier);
5939 early_initcall(migration_init);
5944 #ifdef CONFIG_SCHED_DEBUG
5946 static __read_mostly int sched_domain_debug_enabled;
5948 static int __init sched_domain_debug_setup(char *str)
5950 sched_domain_debug_enabled = 1;
5954 early_param("sched_debug", sched_domain_debug_setup);
5956 static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
5957 struct cpumask *groupmask)
5959 struct sched_group *group = sd->groups;
5962 cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd));
5963 cpumask_clear(groupmask);
5965 printk(KERN_DEBUG "%*s domain %d: ", level, "", level);
5967 if (!(sd->flags & SD_LOAD_BALANCE)) {
5968 printk("does not load-balance\n");
5970 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain"
5975 printk(KERN_CONT "span %s level %s\n", str, sd->name);
5977 if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) {
5978 printk(KERN_ERR "ERROR: domain->span does not contain "
5981 if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) {
5982 printk(KERN_ERR "ERROR: domain->groups does not contain"
5986 printk(KERN_DEBUG "%*s groups:", level + 1, "");
5990 printk(KERN_ERR "ERROR: group is NULL\n");
5994 if (!group->cpu_power) {
5995 printk(KERN_CONT "\n");
5996 printk(KERN_ERR "ERROR: domain->cpu_power not "
6001 if (!cpumask_weight(sched_group_cpus(group))) {
6002 printk(KERN_CONT "\n");
6003 printk(KERN_ERR "ERROR: empty group\n");
6007 if (cpumask_intersects(groupmask, sched_group_cpus(group))) {
6008 printk(KERN_CONT "\n");
6009 printk(KERN_ERR "ERROR: repeated CPUs\n");
6013 cpumask_or(groupmask, groupmask, sched_group_cpus(group));
6015 cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group));
6017 printk(KERN_CONT " %s", str);
6018 if (group->cpu_power != SCHED_LOAD_SCALE) {
6019 printk(KERN_CONT " (cpu_power = %d)",
6023 group = group->next;
6024 } while (group != sd->groups);
6025 printk(KERN_CONT "\n");
6027 if (!cpumask_equal(sched_domain_span(sd), groupmask))
6028 printk(KERN_ERR "ERROR: groups don't span domain->span\n");
6031 !cpumask_subset(groupmask, sched_domain_span(sd->parent)))
6032 printk(KERN_ERR "ERROR: parent span is not a superset "
6033 "of domain->span\n");
6037 static void sched_domain_debug(struct sched_domain *sd, int cpu)
6039 cpumask_var_t groupmask;
6042 if (!sched_domain_debug_enabled)
6046 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
6050 printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu);
6052 if (!alloc_cpumask_var(&groupmask, GFP_KERNEL)) {
6053 printk(KERN_DEBUG "Cannot load-balance (out of memory)\n");
6058 if (sched_domain_debug_one(sd, cpu, level, groupmask))
6065 free_cpumask_var(groupmask);
6067 #else /* !CONFIG_SCHED_DEBUG */
6068 # define sched_domain_debug(sd, cpu) do { } while (0)
6069 #endif /* CONFIG_SCHED_DEBUG */
6071 static int sd_degenerate(struct sched_domain *sd)
6073 if (cpumask_weight(sched_domain_span(sd)) == 1)
6076 /* Following flags need at least 2 groups */
6077 if (sd->flags & (SD_LOAD_BALANCE |
6078 SD_BALANCE_NEWIDLE |
6082 SD_SHARE_PKG_RESOURCES)) {
6083 if (sd->groups != sd->groups->next)
6087 /* Following flags don't use groups */
6088 if (sd->flags & (SD_WAKE_AFFINE))
6095 sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
6097 unsigned long cflags = sd->flags, pflags = parent->flags;
6099 if (sd_degenerate(parent))
6102 if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent)))
6105 /* Flags needing groups don't count if only 1 group in parent */
6106 if (parent->groups == parent->groups->next) {
6107 pflags &= ~(SD_LOAD_BALANCE |
6108 SD_BALANCE_NEWIDLE |
6112 SD_SHARE_PKG_RESOURCES);
6113 if (nr_node_ids == 1)
6114 pflags &= ~SD_SERIALIZE;
6116 if (~cflags & pflags)
6122 static void free_rootdomain(struct root_domain *rd)
6124 synchronize_sched();
6126 cpupri_cleanup(&rd->cpupri);
6128 free_cpumask_var(rd->rto_mask);
6129 free_cpumask_var(rd->online);
6130 free_cpumask_var(rd->span);
6134 static void rq_attach_root(struct rq *rq, struct root_domain *rd)
6136 struct root_domain *old_rd = NULL;
6137 unsigned long flags;
6139 raw_spin_lock_irqsave(&rq->lock, flags);
6144 if (cpumask_test_cpu(rq->cpu, old_rd->online))
6147 cpumask_clear_cpu(rq->cpu, old_rd->span);
6150 * If we dont want to free the old_rt yet then
6151 * set old_rd to NULL to skip the freeing later
6154 if (!atomic_dec_and_test(&old_rd->refcount))
6158 atomic_inc(&rd->refcount);
6161 cpumask_set_cpu(rq->cpu, rd->span);
6162 if (cpumask_test_cpu(rq->cpu, cpu_active_mask))
6165 raw_spin_unlock_irqrestore(&rq->lock, flags);
6168 free_rootdomain(old_rd);
6171 static int init_rootdomain(struct root_domain *rd, bool bootmem)
6173 gfp_t gfp = GFP_KERNEL;
6175 memset(rd, 0, sizeof(*rd));
6180 if (!alloc_cpumask_var(&rd->span, gfp))
6182 if (!alloc_cpumask_var(&rd->online, gfp))
6184 if (!alloc_cpumask_var(&rd->rto_mask, gfp))
6187 if (cpupri_init(&rd->cpupri, bootmem) != 0)
6192 free_cpumask_var(rd->rto_mask);
6194 free_cpumask_var(rd->online);
6196 free_cpumask_var(rd->span);
6201 static void init_defrootdomain(void)
6203 init_rootdomain(&def_root_domain, true);
6205 atomic_set(&def_root_domain.refcount, 1);
6208 static struct root_domain *alloc_rootdomain(void)
6210 struct root_domain *rd;
6212 rd = kmalloc(sizeof(*rd), GFP_KERNEL);
6216 if (init_rootdomain(rd, false) != 0) {
6225 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
6226 * hold the hotplug lock.
6229 cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
6231 struct rq *rq = cpu_rq(cpu);
6232 struct sched_domain *tmp;
6234 /* Remove the sched domains which do not contribute to scheduling. */
6235 for (tmp = sd; tmp; ) {
6236 struct sched_domain *parent = tmp->parent;
6240 if (sd_parent_degenerate(tmp, parent)) {
6241 tmp->parent = parent->parent;
6243 parent->parent->child = tmp;
6248 if (sd && sd_degenerate(sd)) {
6254 sched_domain_debug(sd, cpu);
6256 rq_attach_root(rq, rd);
6257 rcu_assign_pointer(rq->sd, sd);
6260 /* cpus with isolated domains */
6261 static cpumask_var_t cpu_isolated_map;
6263 /* Setup the mask of cpus configured for isolated domains */
6264 static int __init isolated_cpu_setup(char *str)
6266 alloc_bootmem_cpumask_var(&cpu_isolated_map);
6267 cpulist_parse(str, cpu_isolated_map);
6271 __setup("isolcpus=", isolated_cpu_setup);
6274 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
6275 * to a function which identifies what group(along with sched group) a CPU
6276 * belongs to. The return value of group_fn must be a >= 0 and < nr_cpu_ids
6277 * (due to the fact that we keep track of groups covered with a struct cpumask).
6279 * init_sched_build_groups will build a circular linked list of the groups
6280 * covered by the given span, and will set each group's ->cpumask correctly,
6281 * and ->cpu_power to 0.
6284 init_sched_build_groups(const struct cpumask *span,
6285 const struct cpumask *cpu_map,
6286 int (*group_fn)(int cpu, const struct cpumask *cpu_map,
6287 struct sched_group **sg,
6288 struct cpumask *tmpmask),
6289 struct cpumask *covered, struct cpumask *tmpmask)
6291 struct sched_group *first = NULL, *last = NULL;
6294 cpumask_clear(covered);
6296 for_each_cpu(i, span) {
6297 struct sched_group *sg;
6298 int group = group_fn(i, cpu_map, &sg, tmpmask);
6301 if (cpumask_test_cpu(i, covered))
6304 cpumask_clear(sched_group_cpus(sg));
6307 for_each_cpu(j, span) {
6308 if (group_fn(j, cpu_map, NULL, tmpmask) != group)
6311 cpumask_set_cpu(j, covered);
6312 cpumask_set_cpu(j, sched_group_cpus(sg));
6323 #define SD_NODES_PER_DOMAIN 16
6328 * find_next_best_node - find the next node to include in a sched_domain
6329 * @node: node whose sched_domain we're building
6330 * @used_nodes: nodes already in the sched_domain
6332 * Find the next node to include in a given scheduling domain. Simply
6333 * finds the closest node not already in the @used_nodes map.
6335 * Should use nodemask_t.
6337 static int find_next_best_node(int node, nodemask_t *used_nodes)
6339 int i, n, val, min_val, best_node = 0;
6343 for (i = 0; i < nr_node_ids; i++) {
6344 /* Start at @node */
6345 n = (node + i) % nr_node_ids;
6347 if (!nr_cpus_node(n))
6350 /* Skip already used nodes */
6351 if (node_isset(n, *used_nodes))
6354 /* Simple min distance search */
6355 val = node_distance(node, n);
6357 if (val < min_val) {
6363 node_set(best_node, *used_nodes);
6368 * sched_domain_node_span - get a cpumask for a node's sched_domain
6369 * @node: node whose cpumask we're constructing
6370 * @span: resulting cpumask
6372 * Given a node, construct a good cpumask for its sched_domain to span. It
6373 * should be one that prevents unnecessary balancing, but also spreads tasks
6376 static void sched_domain_node_span(int node, struct cpumask *span)
6378 nodemask_t used_nodes;
6381 cpumask_clear(span);
6382 nodes_clear(used_nodes);
6384 cpumask_or(span, span, cpumask_of_node(node));
6385 node_set(node, used_nodes);
6387 for (i = 1; i < SD_NODES_PER_DOMAIN; i++) {
6388 int next_node = find_next_best_node(node, &used_nodes);
6390 cpumask_or(span, span, cpumask_of_node(next_node));
6393 #endif /* CONFIG_NUMA */
6395 int sched_smt_power_savings = 0, sched_mc_power_savings = 0;
6398 * The cpus mask in sched_group and sched_domain hangs off the end.
6400 * ( See the the comments in include/linux/sched.h:struct sched_group
6401 * and struct sched_domain. )
6403 struct static_sched_group {
6404 struct sched_group sg;
6405 DECLARE_BITMAP(cpus, CONFIG_NR_CPUS);
6408 struct static_sched_domain {
6409 struct sched_domain sd;
6410 DECLARE_BITMAP(span, CONFIG_NR_CPUS);
6416 cpumask_var_t domainspan;
6417 cpumask_var_t covered;
6418 cpumask_var_t notcovered;
6420 cpumask_var_t nodemask;
6421 cpumask_var_t this_sibling_map;
6422 cpumask_var_t this_core_map;
6423 cpumask_var_t send_covered;
6424 cpumask_var_t tmpmask;
6425 struct sched_group **sched_group_nodes;
6426 struct root_domain *rd;
6430 sa_sched_groups = 0,
6435 sa_this_sibling_map,
6437 sa_sched_group_nodes,
6447 * SMT sched-domains:
6449 #ifdef CONFIG_SCHED_SMT
6450 static DEFINE_PER_CPU(struct static_sched_domain, cpu_domains);
6451 static DEFINE_PER_CPU(struct static_sched_group, sched_groups);
6454 cpu_to_cpu_group(int cpu, const struct cpumask *cpu_map,
6455 struct sched_group **sg, struct cpumask *unused)
6458 *sg = &per_cpu(sched_groups, cpu).sg;
6461 #endif /* CONFIG_SCHED_SMT */
6464 * multi-core sched-domains:
6466 #ifdef CONFIG_SCHED_MC
6467 static DEFINE_PER_CPU(struct static_sched_domain, core_domains);
6468 static DEFINE_PER_CPU(struct static_sched_group, sched_group_core);
6469 #endif /* CONFIG_SCHED_MC */
6471 #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
6473 cpu_to_core_group(int cpu, const struct cpumask *cpu_map,
6474 struct sched_group **sg, struct cpumask *mask)
6478 cpumask_and(mask, topology_thread_cpumask(cpu), cpu_map);
6479 group = cpumask_first(mask);
6481 *sg = &per_cpu(sched_group_core, group).sg;
6484 #elif defined(CONFIG_SCHED_MC)
6486 cpu_to_core_group(int cpu, const struct cpumask *cpu_map,
6487 struct sched_group **sg, struct cpumask *unused)
6490 *sg = &per_cpu(sched_group_core, cpu).sg;
6495 static DEFINE_PER_CPU(struct static_sched_domain, phys_domains);
6496 static DEFINE_PER_CPU(struct static_sched_group, sched_group_phys);
6499 cpu_to_phys_group(int cpu, const struct cpumask *cpu_map,
6500 struct sched_group **sg, struct cpumask *mask)
6503 #ifdef CONFIG_SCHED_MC
6504 cpumask_and(mask, cpu_coregroup_mask(cpu), cpu_map);
6505 group = cpumask_first(mask);
6506 #elif defined(CONFIG_SCHED_SMT)
6507 cpumask_and(mask, topology_thread_cpumask(cpu), cpu_map);
6508 group = cpumask_first(mask);
6513 *sg = &per_cpu(sched_group_phys, group).sg;
6519 * The init_sched_build_groups can't handle what we want to do with node
6520 * groups, so roll our own. Now each node has its own list of groups which
6521 * gets dynamically allocated.
6523 static DEFINE_PER_CPU(struct static_sched_domain, node_domains);
6524 static struct sched_group ***sched_group_nodes_bycpu;
6526 static DEFINE_PER_CPU(struct static_sched_domain, allnodes_domains);
6527 static DEFINE_PER_CPU(struct static_sched_group, sched_group_allnodes);
6529 static int cpu_to_allnodes_group(int cpu, const struct cpumask *cpu_map,
6530 struct sched_group **sg,
6531 struct cpumask *nodemask)
6535 cpumask_and(nodemask, cpumask_of_node(cpu_to_node(cpu)), cpu_map);
6536 group = cpumask_first(nodemask);
6539 *sg = &per_cpu(sched_group_allnodes, group).sg;
6543 static void init_numa_sched_groups_power(struct sched_group *group_head)
6545 struct sched_group *sg = group_head;
6551 for_each_cpu(j, sched_group_cpus(sg)) {
6552 struct sched_domain *sd;
6554 sd = &per_cpu(phys_domains, j).sd;
6555 if (j != group_first_cpu(sd->groups)) {
6557 * Only add "power" once for each
6563 sg->cpu_power += sd->groups->cpu_power;
6566 } while (sg != group_head);
6569 static int build_numa_sched_groups(struct s_data *d,
6570 const struct cpumask *cpu_map, int num)
6572 struct sched_domain *sd;
6573 struct sched_group *sg, *prev;
6576 cpumask_clear(d->covered);
6577 cpumask_and(d->nodemask, cpumask_of_node(num), cpu_map);
6578 if (cpumask_empty(d->nodemask)) {
6579 d->sched_group_nodes[num] = NULL;
6583 sched_domain_node_span(num, d->domainspan);
6584 cpumask_and(d->domainspan, d->domainspan, cpu_map);
6586 sg = kmalloc_node(sizeof(struct sched_group) + cpumask_size(),
6589 printk(KERN_WARNING "Can not alloc domain group for node %d\n",
6593 d->sched_group_nodes[num] = sg;
6595 for_each_cpu(j, d->nodemask) {
6596 sd = &per_cpu(node_domains, j).sd;
6601 cpumask_copy(sched_group_cpus(sg), d->nodemask);
6603 cpumask_or(d->covered, d->covered, d->nodemask);
6606 for (j = 0; j < nr_node_ids; j++) {
6607 n = (num + j) % nr_node_ids;
6608 cpumask_complement(d->notcovered, d->covered);
6609 cpumask_and(d->tmpmask, d->notcovered, cpu_map);
6610 cpumask_and(d->tmpmask, d->tmpmask, d->domainspan);
6611 if (cpumask_empty(d->tmpmask))
6613 cpumask_and(d->tmpmask, d->tmpmask, cpumask_of_node(n));
6614 if (cpumask_empty(d->tmpmask))
6616 sg = kmalloc_node(sizeof(struct sched_group) + cpumask_size(),
6620 "Can not alloc domain group for node %d\n", j);
6624 cpumask_copy(sched_group_cpus(sg), d->tmpmask);
6625 sg->next = prev->next;
6626 cpumask_or(d->covered, d->covered, d->tmpmask);
6633 #endif /* CONFIG_NUMA */
6636 /* Free memory allocated for various sched_group structures */
6637 static void free_sched_groups(const struct cpumask *cpu_map,
6638 struct cpumask *nodemask)
6642 for_each_cpu(cpu, cpu_map) {
6643 struct sched_group **sched_group_nodes
6644 = sched_group_nodes_bycpu[cpu];
6646 if (!sched_group_nodes)
6649 for (i = 0; i < nr_node_ids; i++) {
6650 struct sched_group *oldsg, *sg = sched_group_nodes[i];
6652 cpumask_and(nodemask, cpumask_of_node(i), cpu_map);
6653 if (cpumask_empty(nodemask))
6663 if (oldsg != sched_group_nodes[i])
6666 kfree(sched_group_nodes);
6667 sched_group_nodes_bycpu[cpu] = NULL;
6670 #else /* !CONFIG_NUMA */
6671 static void free_sched_groups(const struct cpumask *cpu_map,
6672 struct cpumask *nodemask)
6675 #endif /* CONFIG_NUMA */
6678 * Initialize sched groups cpu_power.
6680 * cpu_power indicates the capacity of sched group, which is used while
6681 * distributing the load between different sched groups in a sched domain.
6682 * Typically cpu_power for all the groups in a sched domain will be same unless
6683 * there are asymmetries in the topology. If there are asymmetries, group
6684 * having more cpu_power will pickup more load compared to the group having
6687 static void init_sched_groups_power(int cpu, struct sched_domain *sd)
6689 struct sched_domain *child;
6690 struct sched_group *group;
6694 WARN_ON(!sd || !sd->groups);
6696 if (cpu != group_first_cpu(sd->groups))
6701 sd->groups->cpu_power = 0;
6704 power = SCHED_LOAD_SCALE;
6705 weight = cpumask_weight(sched_domain_span(sd));
6707 * SMT siblings share the power of a single core.
6708 * Usually multiple threads get a better yield out of
6709 * that one core than a single thread would have,
6710 * reflect that in sd->smt_gain.
6712 if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) {
6713 power *= sd->smt_gain;
6715 power >>= SCHED_LOAD_SHIFT;
6717 sd->groups->cpu_power += power;
6722 * Add cpu_power of each child group to this groups cpu_power.
6724 group = child->groups;
6726 sd->groups->cpu_power += group->cpu_power;
6727 group = group->next;
6728 } while (group != child->groups);
6732 * Initializers for schedule domains
6733 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
6736 #ifdef CONFIG_SCHED_DEBUG
6737 # define SD_INIT_NAME(sd, type) sd->name = #type
6739 # define SD_INIT_NAME(sd, type) do { } while (0)
6742 #define SD_INIT(sd, type) sd_init_##type(sd)
6744 #define SD_INIT_FUNC(type) \
6745 static noinline void sd_init_##type(struct sched_domain *sd) \
6747 memset(sd, 0, sizeof(*sd)); \
6748 *sd = SD_##type##_INIT; \
6749 sd->level = SD_LV_##type; \
6750 SD_INIT_NAME(sd, type); \
6755 SD_INIT_FUNC(ALLNODES)
6758 #ifdef CONFIG_SCHED_SMT
6759 SD_INIT_FUNC(SIBLING)
6761 #ifdef CONFIG_SCHED_MC
6765 static int default_relax_domain_level = -1;
6767 static int __init setup_relax_domain_level(char *str)
6771 val = simple_strtoul(str, NULL, 0);
6772 if (val < SD_LV_MAX)
6773 default_relax_domain_level = val;
6777 __setup("relax_domain_level=", setup_relax_domain_level);
6779 static void set_domain_attribute(struct sched_domain *sd,
6780 struct sched_domain_attr *attr)
6784 if (!attr || attr->relax_domain_level < 0) {
6785 if (default_relax_domain_level < 0)
6788 request = default_relax_domain_level;
6790 request = attr->relax_domain_level;
6791 if (request < sd->level) {
6792 /* turn off idle balance on this domain */
6793 sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
6795 /* turn on idle balance on this domain */
6796 sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
6800 static void __free_domain_allocs(struct s_data *d, enum s_alloc what,
6801 const struct cpumask *cpu_map)
6804 case sa_sched_groups:
6805 free_sched_groups(cpu_map, d->tmpmask); /* fall through */
6806 d->sched_group_nodes = NULL;
6808 free_rootdomain(d->rd); /* fall through */
6810 free_cpumask_var(d->tmpmask); /* fall through */
6811 case sa_send_covered:
6812 free_cpumask_var(d->send_covered); /* fall through */
6813 case sa_this_core_map:
6814 free_cpumask_var(d->this_core_map); /* fall through */
6815 case sa_this_sibling_map:
6816 free_cpumask_var(d->this_sibling_map); /* fall through */
6818 free_cpumask_var(d->nodemask); /* fall through */
6819 case sa_sched_group_nodes:
6821 kfree(d->sched_group_nodes); /* fall through */
6823 free_cpumask_var(d->notcovered); /* fall through */
6825 free_cpumask_var(d->covered); /* fall through */
6827 free_cpumask_var(d->domainspan); /* fall through */
6834 static enum s_alloc __visit_domain_allocation_hell(struct s_data *d,
6835 const struct cpumask *cpu_map)
6838 if (!alloc_cpumask_var(&d->domainspan, GFP_KERNEL))
6840 if (!alloc_cpumask_var(&d->covered, GFP_KERNEL))
6841 return sa_domainspan;
6842 if (!alloc_cpumask_var(&d->notcovered, GFP_KERNEL))
6844 /* Allocate the per-node list of sched groups */
6845 d->sched_group_nodes = kcalloc(nr_node_ids,
6846 sizeof(struct sched_group *), GFP_KERNEL);
6847 if (!d->sched_group_nodes) {
6848 printk(KERN_WARNING "Can not alloc sched group node list\n");
6849 return sa_notcovered;
6851 sched_group_nodes_bycpu[cpumask_first(cpu_map)] = d->sched_group_nodes;
6853 if (!alloc_cpumask_var(&d->nodemask, GFP_KERNEL))
6854 return sa_sched_group_nodes;
6855 if (!alloc_cpumask_var(&d->this_sibling_map, GFP_KERNEL))
6857 if (!alloc_cpumask_var(&d->this_core_map, GFP_KERNEL))
6858 return sa_this_sibling_map;
6859 if (!alloc_cpumask_var(&d->send_covered, GFP_KERNEL))
6860 return sa_this_core_map;
6861 if (!alloc_cpumask_var(&d->tmpmask, GFP_KERNEL))
6862 return sa_send_covered;
6863 d->rd = alloc_rootdomain();
6865 printk(KERN_WARNING "Cannot alloc root domain\n");
6868 return sa_rootdomain;
6871 static struct sched_domain *__build_numa_sched_domains(struct s_data *d,
6872 const struct cpumask *cpu_map, struct sched_domain_attr *attr, int i)
6874 struct sched_domain *sd = NULL;
6876 struct sched_domain *parent;
6879 if (cpumask_weight(cpu_map) >
6880 SD_NODES_PER_DOMAIN * cpumask_weight(d->nodemask)) {
6881 sd = &per_cpu(allnodes_domains, i).sd;
6882 SD_INIT(sd, ALLNODES);
6883 set_domain_attribute(sd, attr);
6884 cpumask_copy(sched_domain_span(sd), cpu_map);
6885 cpu_to_allnodes_group(i, cpu_map, &sd->groups, d->tmpmask);
6890 sd = &per_cpu(node_domains, i).sd;
6892 set_domain_attribute(sd, attr);
6893 sched_domain_node_span(cpu_to_node(i), sched_domain_span(sd));
6894 sd->parent = parent;
6897 cpumask_and(sched_domain_span(sd), sched_domain_span(sd), cpu_map);
6902 static struct sched_domain *__build_cpu_sched_domain(struct s_data *d,
6903 const struct cpumask *cpu_map, struct sched_domain_attr *attr,
6904 struct sched_domain *parent, int i)
6906 struct sched_domain *sd;
6907 sd = &per_cpu(phys_domains, i).sd;
6909 set_domain_attribute(sd, attr);
6910 cpumask_copy(sched_domain_span(sd), d->nodemask);
6911 sd->parent = parent;
6914 cpu_to_phys_group(i, cpu_map, &sd->groups, d->tmpmask);
6918 static struct sched_domain *__build_mc_sched_domain(struct s_data *d,
6919 const struct cpumask *cpu_map, struct sched_domain_attr *attr,
6920 struct sched_domain *parent, int i)
6922 struct sched_domain *sd = parent;
6923 #ifdef CONFIG_SCHED_MC
6924 sd = &per_cpu(core_domains, i).sd;
6926 set_domain_attribute(sd, attr);
6927 cpumask_and(sched_domain_span(sd), cpu_map, cpu_coregroup_mask(i));
6928 sd->parent = parent;
6930 cpu_to_core_group(i, cpu_map, &sd->groups, d->tmpmask);
6935 static struct sched_domain *__build_smt_sched_domain(struct s_data *d,
6936 const struct cpumask *cpu_map, struct sched_domain_attr *attr,
6937 struct sched_domain *parent, int i)
6939 struct sched_domain *sd = parent;
6940 #ifdef CONFIG_SCHED_SMT
6941 sd = &per_cpu(cpu_domains, i).sd;
6942 SD_INIT(sd, SIBLING);
6943 set_domain_attribute(sd, attr);
6944 cpumask_and(sched_domain_span(sd), cpu_map, topology_thread_cpumask(i));
6945 sd->parent = parent;
6947 cpu_to_cpu_group(i, cpu_map, &sd->groups, d->tmpmask);
6952 static void build_sched_groups(struct s_data *d, enum sched_domain_level l,
6953 const struct cpumask *cpu_map, int cpu)
6956 #ifdef CONFIG_SCHED_SMT
6957 case SD_LV_SIBLING: /* set up CPU (sibling) groups */
6958 cpumask_and(d->this_sibling_map, cpu_map,
6959 topology_thread_cpumask(cpu));
6960 if (cpu == cpumask_first(d->this_sibling_map))
6961 init_sched_build_groups(d->this_sibling_map, cpu_map,
6963 d->send_covered, d->tmpmask);
6966 #ifdef CONFIG_SCHED_MC
6967 case SD_LV_MC: /* set up multi-core groups */
6968 cpumask_and(d->this_core_map, cpu_map, cpu_coregroup_mask(cpu));
6969 if (cpu == cpumask_first(d->this_core_map))
6970 init_sched_build_groups(d->this_core_map, cpu_map,
6972 d->send_covered, d->tmpmask);
6975 case SD_LV_CPU: /* set up physical groups */
6976 cpumask_and(d->nodemask, cpumask_of_node(cpu), cpu_map);
6977 if (!cpumask_empty(d->nodemask))
6978 init_sched_build_groups(d->nodemask, cpu_map,
6980 d->send_covered, d->tmpmask);
6983 case SD_LV_ALLNODES:
6984 init_sched_build_groups(cpu_map, cpu_map, &cpu_to_allnodes_group,
6985 d->send_covered, d->tmpmask);
6994 * Build sched domains for a given set of cpus and attach the sched domains
6995 * to the individual cpus
6997 static int __build_sched_domains(const struct cpumask *cpu_map,
6998 struct sched_domain_attr *attr)
7000 enum s_alloc alloc_state = sa_none;
7002 struct sched_domain *sd;
7008 alloc_state = __visit_domain_allocation_hell(&d, cpu_map);
7009 if (alloc_state != sa_rootdomain)
7011 alloc_state = sa_sched_groups;
7014 * Set up domains for cpus specified by the cpu_map.
7016 for_each_cpu(i, cpu_map) {
7017 cpumask_and(d.nodemask, cpumask_of_node(cpu_to_node(i)),
7020 sd = __build_numa_sched_domains(&d, cpu_map, attr, i);
7021 sd = __build_cpu_sched_domain(&d, cpu_map, attr, sd, i);
7022 sd = __build_mc_sched_domain(&d, cpu_map, attr, sd, i);
7023 sd = __build_smt_sched_domain(&d, cpu_map, attr, sd, i);
7026 for_each_cpu(i, cpu_map) {
7027 build_sched_groups(&d, SD_LV_SIBLING, cpu_map, i);
7028 build_sched_groups(&d, SD_LV_MC, cpu_map, i);
7031 /* Set up physical groups */
7032 for (i = 0; i < nr_node_ids; i++)
7033 build_sched_groups(&d, SD_LV_CPU, cpu_map, i);
7036 /* Set up node groups */
7038 build_sched_groups(&d, SD_LV_ALLNODES, cpu_map, 0);
7040 for (i = 0; i < nr_node_ids; i++)
7041 if (build_numa_sched_groups(&d, cpu_map, i))
7045 /* Calculate CPU power for physical packages and nodes */
7046 #ifdef CONFIG_SCHED_SMT
7047 for_each_cpu(i, cpu_map) {
7048 sd = &per_cpu(cpu_domains, i).sd;
7049 init_sched_groups_power(i, sd);
7052 #ifdef CONFIG_SCHED_MC
7053 for_each_cpu(i, cpu_map) {
7054 sd = &per_cpu(core_domains, i).sd;
7055 init_sched_groups_power(i, sd);
7059 for_each_cpu(i, cpu_map) {
7060 sd = &per_cpu(phys_domains, i).sd;
7061 init_sched_groups_power(i, sd);
7065 for (i = 0; i < nr_node_ids; i++)
7066 init_numa_sched_groups_power(d.sched_group_nodes[i]);
7068 if (d.sd_allnodes) {
7069 struct sched_group *sg;
7071 cpu_to_allnodes_group(cpumask_first(cpu_map), cpu_map, &sg,
7073 init_numa_sched_groups_power(sg);
7077 /* Attach the domains */
7078 for_each_cpu(i, cpu_map) {
7079 #ifdef CONFIG_SCHED_SMT
7080 sd = &per_cpu(cpu_domains, i).sd;
7081 #elif defined(CONFIG_SCHED_MC)
7082 sd = &per_cpu(core_domains, i).sd;
7084 sd = &per_cpu(phys_domains, i).sd;
7086 cpu_attach_domain(sd, d.rd, i);
7089 d.sched_group_nodes = NULL; /* don't free this we still need it */
7090 __free_domain_allocs(&d, sa_tmpmask, cpu_map);
7094 __free_domain_allocs(&d, alloc_state, cpu_map);
7098 static int build_sched_domains(const struct cpumask *cpu_map)
7100 return __build_sched_domains(cpu_map, NULL);
7103 static cpumask_var_t *doms_cur; /* current sched domains */
7104 static int ndoms_cur; /* number of sched domains in 'doms_cur' */
7105 static struct sched_domain_attr *dattr_cur;
7106 /* attribues of custom domains in 'doms_cur' */
7109 * Special case: If a kmalloc of a doms_cur partition (array of
7110 * cpumask) fails, then fallback to a single sched domain,
7111 * as determined by the single cpumask fallback_doms.
7113 static cpumask_var_t fallback_doms;
7116 * arch_update_cpu_topology lets virtualized architectures update the
7117 * cpu core maps. It is supposed to return 1 if the topology changed
7118 * or 0 if it stayed the same.
7120 int __attribute__((weak)) arch_update_cpu_topology(void)
7125 cpumask_var_t *alloc_sched_domains(unsigned int ndoms)
7128 cpumask_var_t *doms;
7130 doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL);
7133 for (i = 0; i < ndoms; i++) {
7134 if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) {
7135 free_sched_domains(doms, i);
7142 void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms)
7145 for (i = 0; i < ndoms; i++)
7146 free_cpumask_var(doms[i]);
7151 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
7152 * For now this just excludes isolated cpus, but could be used to
7153 * exclude other special cases in the future.
7155 static int arch_init_sched_domains(const struct cpumask *cpu_map)
7159 arch_update_cpu_topology();
7161 doms_cur = alloc_sched_domains(ndoms_cur);
7163 doms_cur = &fallback_doms;
7164 cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map);
7166 err = build_sched_domains(doms_cur[0]);
7167 register_sched_domain_sysctl();
7172 static void arch_destroy_sched_domains(const struct cpumask *cpu_map,
7173 struct cpumask *tmpmask)
7175 free_sched_groups(cpu_map, tmpmask);
7179 * Detach sched domains from a group of cpus specified in cpu_map
7180 * These cpus will now be attached to the NULL domain
7182 static void detach_destroy_domains(const struct cpumask *cpu_map)
7184 /* Save because hotplug lock held. */
7185 static DECLARE_BITMAP(tmpmask, CONFIG_NR_CPUS);
7188 for_each_cpu(i, cpu_map)
7189 cpu_attach_domain(NULL, &def_root_domain, i);
7190 synchronize_sched();
7191 arch_destroy_sched_domains(cpu_map, to_cpumask(tmpmask));
7194 /* handle null as "default" */
7195 static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
7196 struct sched_domain_attr *new, int idx_new)
7198 struct sched_domain_attr tmp;
7205 return !memcmp(cur ? (cur + idx_cur) : &tmp,
7206 new ? (new + idx_new) : &tmp,
7207 sizeof(struct sched_domain_attr));
7211 * Partition sched domains as specified by the 'ndoms_new'
7212 * cpumasks in the array doms_new[] of cpumasks. This compares
7213 * doms_new[] to the current sched domain partitioning, doms_cur[].
7214 * It destroys each deleted domain and builds each new domain.
7216 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
7217 * The masks don't intersect (don't overlap.) We should setup one
7218 * sched domain for each mask. CPUs not in any of the cpumasks will
7219 * not be load balanced. If the same cpumask appears both in the
7220 * current 'doms_cur' domains and in the new 'doms_new', we can leave
7223 * The passed in 'doms_new' should be allocated using
7224 * alloc_sched_domains. This routine takes ownership of it and will
7225 * free_sched_domains it when done with it. If the caller failed the
7226 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
7227 * and partition_sched_domains() will fallback to the single partition
7228 * 'fallback_doms', it also forces the domains to be rebuilt.
7230 * If doms_new == NULL it will be replaced with cpu_online_mask.
7231 * ndoms_new == 0 is a special case for destroying existing domains,
7232 * and it will not create the default domain.
7234 * Call with hotplug lock held
7236 void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
7237 struct sched_domain_attr *dattr_new)
7242 mutex_lock(&sched_domains_mutex);
7244 /* always unregister in case we don't destroy any domains */
7245 unregister_sched_domain_sysctl();
7247 /* Let architecture update cpu core mappings. */
7248 new_topology = arch_update_cpu_topology();
7250 n = doms_new ? ndoms_new : 0;
7252 /* Destroy deleted domains */
7253 for (i = 0; i < ndoms_cur; i++) {
7254 for (j = 0; j < n && !new_topology; j++) {
7255 if (cpumask_equal(doms_cur[i], doms_new[j])
7256 && dattrs_equal(dattr_cur, i, dattr_new, j))
7259 /* no match - a current sched domain not in new doms_new[] */
7260 detach_destroy_domains(doms_cur[i]);
7265 if (doms_new == NULL) {
7267 doms_new = &fallback_doms;
7268 cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map);
7269 WARN_ON_ONCE(dattr_new);
7272 /* Build new domains */
7273 for (i = 0; i < ndoms_new; i++) {
7274 for (j = 0; j < ndoms_cur && !new_topology; j++) {
7275 if (cpumask_equal(doms_new[i], doms_cur[j])
7276 && dattrs_equal(dattr_new, i, dattr_cur, j))
7279 /* no match - add a new doms_new */
7280 __build_sched_domains(doms_new[i],
7281 dattr_new ? dattr_new + i : NULL);
7286 /* Remember the new sched domains */
7287 if (doms_cur != &fallback_doms)
7288 free_sched_domains(doms_cur, ndoms_cur);
7289 kfree(dattr_cur); /* kfree(NULL) is safe */
7290 doms_cur = doms_new;
7291 dattr_cur = dattr_new;
7292 ndoms_cur = ndoms_new;
7294 register_sched_domain_sysctl();
7296 mutex_unlock(&sched_domains_mutex);
7299 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
7300 static void arch_reinit_sched_domains(void)
7304 /* Destroy domains first to force the rebuild */
7305 partition_sched_domains(0, NULL, NULL);
7307 rebuild_sched_domains();
7311 static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt)
7313 unsigned int level = 0;
7315 if (sscanf(buf, "%u", &level) != 1)
7319 * level is always be positive so don't check for
7320 * level < POWERSAVINGS_BALANCE_NONE which is 0
7321 * What happens on 0 or 1 byte write,
7322 * need to check for count as well?
7325 if (level >= MAX_POWERSAVINGS_BALANCE_LEVELS)
7329 sched_smt_power_savings = level;
7331 sched_mc_power_savings = level;
7333 arch_reinit_sched_domains();
7338 #ifdef CONFIG_SCHED_MC
7339 static ssize_t sched_mc_power_savings_show(struct sysdev_class *class,
7340 struct sysdev_class_attribute *attr,
7343 return sprintf(page, "%u\n", sched_mc_power_savings);
7345 static ssize_t sched_mc_power_savings_store(struct sysdev_class *class,
7346 struct sysdev_class_attribute *attr,
7347 const char *buf, size_t count)
7349 return sched_power_savings_store(buf, count, 0);
7351 static SYSDEV_CLASS_ATTR(sched_mc_power_savings, 0644,
7352 sched_mc_power_savings_show,
7353 sched_mc_power_savings_store);
7356 #ifdef CONFIG_SCHED_SMT
7357 static ssize_t sched_smt_power_savings_show(struct sysdev_class *dev,
7358 struct sysdev_class_attribute *attr,
7361 return sprintf(page, "%u\n", sched_smt_power_savings);
7363 static ssize_t sched_smt_power_savings_store(struct sysdev_class *dev,
7364 struct sysdev_class_attribute *attr,
7365 const char *buf, size_t count)
7367 return sched_power_savings_store(buf, count, 1);
7369 static SYSDEV_CLASS_ATTR(sched_smt_power_savings, 0644,
7370 sched_smt_power_savings_show,
7371 sched_smt_power_savings_store);
7374 int __init sched_create_sysfs_power_savings_entries(struct sysdev_class *cls)
7378 #ifdef CONFIG_SCHED_SMT
7380 err = sysfs_create_file(&cls->kset.kobj,
7381 &attr_sched_smt_power_savings.attr);
7383 #ifdef CONFIG_SCHED_MC
7384 if (!err && mc_capable())
7385 err = sysfs_create_file(&cls->kset.kobj,
7386 &attr_sched_mc_power_savings.attr);
7390 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
7392 #ifndef CONFIG_CPUSETS
7394 * Add online and remove offline CPUs from the scheduler domains.
7395 * When cpusets are enabled they take over this function.
7397 static int update_sched_domains(struct notifier_block *nfb,
7398 unsigned long action, void *hcpu)
7402 case CPU_ONLINE_FROZEN:
7403 case CPU_DOWN_PREPARE:
7404 case CPU_DOWN_PREPARE_FROZEN:
7405 case CPU_DOWN_FAILED:
7406 case CPU_DOWN_FAILED_FROZEN:
7407 partition_sched_domains(1, NULL, NULL);
7416 static int update_runtime(struct notifier_block *nfb,
7417 unsigned long action, void *hcpu)
7419 int cpu = (int)(long)hcpu;
7422 case CPU_DOWN_PREPARE:
7423 case CPU_DOWN_PREPARE_FROZEN:
7424 disable_runtime(cpu_rq(cpu));
7427 case CPU_DOWN_FAILED:
7428 case CPU_DOWN_FAILED_FROZEN:
7430 case CPU_ONLINE_FROZEN:
7431 enable_runtime(cpu_rq(cpu));
7439 void __init sched_init_smp(void)
7441 cpumask_var_t non_isolated_cpus;
7443 alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL);
7444 alloc_cpumask_var(&fallback_doms, GFP_KERNEL);
7446 #if defined(CONFIG_NUMA)
7447 sched_group_nodes_bycpu = kzalloc(nr_cpu_ids * sizeof(void **),
7449 BUG_ON(sched_group_nodes_bycpu == NULL);
7452 mutex_lock(&sched_domains_mutex);
7453 arch_init_sched_domains(cpu_active_mask);
7454 cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map);
7455 if (cpumask_empty(non_isolated_cpus))
7456 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus);
7457 mutex_unlock(&sched_domains_mutex);
7460 #ifndef CONFIG_CPUSETS
7461 /* XXX: Theoretical race here - CPU may be hotplugged now */
7462 hotcpu_notifier(update_sched_domains, 0);
7465 /* RT runtime code needs to handle some hotplug events */
7466 hotcpu_notifier(update_runtime, 0);
7470 /* Move init over to a non-isolated CPU */
7471 if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0)
7473 sched_init_granularity();
7474 free_cpumask_var(non_isolated_cpus);
7476 init_sched_rt_class();
7479 void __init sched_init_smp(void)
7481 sched_init_granularity();
7483 #endif /* CONFIG_SMP */
7485 const_debug unsigned int sysctl_timer_migration = 1;
7487 int in_sched_functions(unsigned long addr)
7489 return in_lock_functions(addr) ||
7490 (addr >= (unsigned long)__sched_text_start
7491 && addr < (unsigned long)__sched_text_end);
7494 static void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq)
7496 cfs_rq->tasks_timeline = RB_ROOT;
7497 INIT_LIST_HEAD(&cfs_rq->tasks);
7498 #ifdef CONFIG_FAIR_GROUP_SCHED
7501 cfs_rq->min_vruntime = (u64)(-(1LL << 20));
7504 static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
7506 struct rt_prio_array *array;
7509 array = &rt_rq->active;
7510 for (i = 0; i < MAX_RT_PRIO; i++) {
7511 INIT_LIST_HEAD(array->queue + i);
7512 __clear_bit(i, array->bitmap);
7514 /* delimiter for bitsearch: */
7515 __set_bit(MAX_RT_PRIO, array->bitmap);
7517 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
7518 rt_rq->highest_prio.curr = MAX_RT_PRIO;
7520 rt_rq->highest_prio.next = MAX_RT_PRIO;
7524 rt_rq->rt_nr_migratory = 0;
7525 rt_rq->overloaded = 0;
7526 plist_head_init_raw(&rt_rq->pushable_tasks, &rq->lock);
7530 rt_rq->rt_throttled = 0;
7531 rt_rq->rt_runtime = 0;
7532 raw_spin_lock_init(&rt_rq->rt_runtime_lock);
7534 #ifdef CONFIG_RT_GROUP_SCHED
7535 rt_rq->rt_nr_boosted = 0;
7540 #ifdef CONFIG_FAIR_GROUP_SCHED
7541 static void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
7542 struct sched_entity *se, int cpu, int add,
7543 struct sched_entity *parent)
7545 struct rq *rq = cpu_rq(cpu);
7546 tg->cfs_rq[cpu] = cfs_rq;
7547 init_cfs_rq(cfs_rq, rq);
7550 list_add(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list);
7553 /* se could be NULL for init_task_group */
7558 se->cfs_rq = &rq->cfs;
7560 se->cfs_rq = parent->my_q;
7563 se->load.weight = tg->shares;
7564 se->load.inv_weight = 0;
7565 se->parent = parent;
7569 #ifdef CONFIG_RT_GROUP_SCHED
7570 static void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
7571 struct sched_rt_entity *rt_se, int cpu, int add,
7572 struct sched_rt_entity *parent)
7574 struct rq *rq = cpu_rq(cpu);
7576 tg->rt_rq[cpu] = rt_rq;
7577 init_rt_rq(rt_rq, rq);
7579 rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime;
7581 list_add(&rt_rq->leaf_rt_rq_list, &rq->leaf_rt_rq_list);
7583 tg->rt_se[cpu] = rt_se;
7588 rt_se->rt_rq = &rq->rt;
7590 rt_se->rt_rq = parent->my_q;
7592 rt_se->my_q = rt_rq;
7593 rt_se->parent = parent;
7594 INIT_LIST_HEAD(&rt_se->run_list);
7598 void __init sched_init(void)
7601 unsigned long alloc_size = 0, ptr;
7603 #ifdef CONFIG_FAIR_GROUP_SCHED
7604 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
7606 #ifdef CONFIG_RT_GROUP_SCHED
7607 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
7609 #ifdef CONFIG_CPUMASK_OFFSTACK
7610 alloc_size += num_possible_cpus() * cpumask_size();
7613 ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT);
7615 #ifdef CONFIG_FAIR_GROUP_SCHED
7616 init_task_group.se = (struct sched_entity **)ptr;
7617 ptr += nr_cpu_ids * sizeof(void **);
7619 init_task_group.cfs_rq = (struct cfs_rq **)ptr;
7620 ptr += nr_cpu_ids * sizeof(void **);
7622 #endif /* CONFIG_FAIR_GROUP_SCHED */
7623 #ifdef CONFIG_RT_GROUP_SCHED
7624 init_task_group.rt_se = (struct sched_rt_entity **)ptr;
7625 ptr += nr_cpu_ids * sizeof(void **);
7627 init_task_group.rt_rq = (struct rt_rq **)ptr;
7628 ptr += nr_cpu_ids * sizeof(void **);
7630 #endif /* CONFIG_RT_GROUP_SCHED */
7631 #ifdef CONFIG_CPUMASK_OFFSTACK
7632 for_each_possible_cpu(i) {
7633 per_cpu(load_balance_tmpmask, i) = (void *)ptr;
7634 ptr += cpumask_size();
7636 #endif /* CONFIG_CPUMASK_OFFSTACK */
7640 init_defrootdomain();
7643 init_rt_bandwidth(&def_rt_bandwidth,
7644 global_rt_period(), global_rt_runtime());
7646 #ifdef CONFIG_RT_GROUP_SCHED
7647 init_rt_bandwidth(&init_task_group.rt_bandwidth,
7648 global_rt_period(), global_rt_runtime());
7649 #endif /* CONFIG_RT_GROUP_SCHED */
7651 #ifdef CONFIG_CGROUP_SCHED
7652 list_add(&init_task_group.list, &task_groups);
7653 INIT_LIST_HEAD(&init_task_group.children);
7655 #endif /* CONFIG_CGROUP_SCHED */
7657 #if defined CONFIG_FAIR_GROUP_SCHED && defined CONFIG_SMP
7658 update_shares_data = __alloc_percpu(nr_cpu_ids * sizeof(unsigned long),
7659 __alignof__(unsigned long));
7661 for_each_possible_cpu(i) {
7665 raw_spin_lock_init(&rq->lock);
7667 rq->calc_load_active = 0;
7668 rq->calc_load_update = jiffies + LOAD_FREQ;
7669 init_cfs_rq(&rq->cfs, rq);
7670 init_rt_rq(&rq->rt, rq);
7671 #ifdef CONFIG_FAIR_GROUP_SCHED
7672 init_task_group.shares = init_task_group_load;
7673 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
7674 #ifdef CONFIG_CGROUP_SCHED
7676 * How much cpu bandwidth does init_task_group get?
7678 * In case of task-groups formed thr' the cgroup filesystem, it
7679 * gets 100% of the cpu resources in the system. This overall
7680 * system cpu resource is divided among the tasks of
7681 * init_task_group and its child task-groups in a fair manner,
7682 * based on each entity's (task or task-group's) weight
7683 * (se->load.weight).
7685 * In other words, if init_task_group has 10 tasks of weight
7686 * 1024) and two child groups A0 and A1 (of weight 1024 each),
7687 * then A0's share of the cpu resource is:
7689 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
7691 * We achieve this by letting init_task_group's tasks sit
7692 * directly in rq->cfs (i.e init_task_group->se[] = NULL).
7694 init_tg_cfs_entry(&init_task_group, &rq->cfs, NULL, i, 1, NULL);
7696 #endif /* CONFIG_FAIR_GROUP_SCHED */
7698 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime;
7699 #ifdef CONFIG_RT_GROUP_SCHED
7700 INIT_LIST_HEAD(&rq->leaf_rt_rq_list);
7701 #ifdef CONFIG_CGROUP_SCHED
7702 init_tg_rt_entry(&init_task_group, &rq->rt, NULL, i, 1, NULL);
7706 for (j = 0; j < CPU_LOAD_IDX_MAX; j++)
7707 rq->cpu_load[j] = 0;
7711 rq->post_schedule = 0;
7712 rq->active_balance = 0;
7713 rq->next_balance = jiffies;
7717 rq->migration_thread = NULL;
7719 rq->avg_idle = 2*sysctl_sched_migration_cost;
7720 INIT_LIST_HEAD(&rq->migration_queue);
7721 rq_attach_root(rq, &def_root_domain);
7724 atomic_set(&rq->nr_iowait, 0);
7727 set_load_weight(&init_task);
7729 #ifdef CONFIG_PREEMPT_NOTIFIERS
7730 INIT_HLIST_HEAD(&init_task.preempt_notifiers);
7734 open_softirq(SCHED_SOFTIRQ, run_rebalance_domains);
7737 #ifdef CONFIG_RT_MUTEXES
7738 plist_head_init_raw(&init_task.pi_waiters, &init_task.pi_lock);
7742 * The boot idle thread does lazy MMU switching as well:
7744 atomic_inc(&init_mm.mm_count);
7745 enter_lazy_tlb(&init_mm, current);
7748 * Make us the idle thread. Technically, schedule() should not be
7749 * called from this thread, however somewhere below it might be,
7750 * but because we are the idle thread, we just pick up running again
7751 * when this runqueue becomes "idle".
7753 init_idle(current, smp_processor_id());
7755 calc_load_update = jiffies + LOAD_FREQ;
7758 * During early bootup we pretend to be a normal task:
7760 current->sched_class = &fair_sched_class;
7762 /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */
7763 zalloc_cpumask_var(&nohz_cpu_mask, GFP_NOWAIT);
7766 zalloc_cpumask_var(&nohz.cpu_mask, GFP_NOWAIT);
7767 alloc_cpumask_var(&nohz.ilb_grp_nohz_mask, GFP_NOWAIT);
7769 /* May be allocated at isolcpus cmdline parse time */
7770 if (cpu_isolated_map == NULL)
7771 zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
7776 scheduler_running = 1;
7779 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
7780 static inline int preempt_count_equals(int preempt_offset)
7782 int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth();
7784 return (nested == PREEMPT_INATOMIC_BASE + preempt_offset);
7787 void __might_sleep(const char *file, int line, int preempt_offset)
7790 static unsigned long prev_jiffy; /* ratelimiting */
7792 if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) ||
7793 system_state != SYSTEM_RUNNING || oops_in_progress)
7795 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
7797 prev_jiffy = jiffies;
7800 "BUG: sleeping function called from invalid context at %s:%d\n",
7803 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
7804 in_atomic(), irqs_disabled(),
7805 current->pid, current->comm);
7807 debug_show_held_locks(current);
7808 if (irqs_disabled())
7809 print_irqtrace_events(current);
7813 EXPORT_SYMBOL(__might_sleep);
7816 #ifdef CONFIG_MAGIC_SYSRQ
7817 static void normalize_task(struct rq *rq, struct task_struct *p)
7821 on_rq = p->se.on_rq;
7823 deactivate_task(rq, p, 0);
7824 __setscheduler(rq, p, SCHED_NORMAL, 0);
7826 activate_task(rq, p, 0);
7827 resched_task(rq->curr);
7831 void normalize_rt_tasks(void)
7833 struct task_struct *g, *p;
7834 unsigned long flags;
7837 read_lock_irqsave(&tasklist_lock, flags);
7838 do_each_thread(g, p) {
7840 * Only normalize user tasks:
7845 p->se.exec_start = 0;
7846 #ifdef CONFIG_SCHEDSTATS
7847 p->se.statistics.wait_start = 0;
7848 p->se.statistics.sleep_start = 0;
7849 p->se.statistics.block_start = 0;
7854 * Renice negative nice level userspace
7857 if (TASK_NICE(p) < 0 && p->mm)
7858 set_user_nice(p, 0);
7862 raw_spin_lock(&p->pi_lock);
7863 rq = __task_rq_lock(p);
7865 normalize_task(rq, p);
7867 __task_rq_unlock(rq);
7868 raw_spin_unlock(&p->pi_lock);
7869 } while_each_thread(g, p);
7871 read_unlock_irqrestore(&tasklist_lock, flags);
7874 #endif /* CONFIG_MAGIC_SYSRQ */
7878 * These functions are only useful for the IA64 MCA handling.
7880 * They can only be called when the whole system has been
7881 * stopped - every CPU needs to be quiescent, and no scheduling
7882 * activity can take place. Using them for anything else would
7883 * be a serious bug, and as a result, they aren't even visible
7884 * under any other configuration.
7888 * curr_task - return the current task for a given cpu.
7889 * @cpu: the processor in question.
7891 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7893 struct task_struct *curr_task(int cpu)
7895 return cpu_curr(cpu);
7899 * set_curr_task - set the current task for a given cpu.
7900 * @cpu: the processor in question.
7901 * @p: the task pointer to set.
7903 * Description: This function must only be used when non-maskable interrupts
7904 * are serviced on a separate stack. It allows the architecture to switch the
7905 * notion of the current task on a cpu in a non-blocking manner. This function
7906 * must be called with all CPU's synchronized, and interrupts disabled, the
7907 * and caller must save the original value of the current task (see
7908 * curr_task() above) and restore that value before reenabling interrupts and
7909 * re-starting the system.
7911 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7913 void set_curr_task(int cpu, struct task_struct *p)
7920 #ifdef CONFIG_FAIR_GROUP_SCHED
7921 static void free_fair_sched_group(struct task_group *tg)
7925 for_each_possible_cpu(i) {
7927 kfree(tg->cfs_rq[i]);
7937 int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
7939 struct cfs_rq *cfs_rq;
7940 struct sched_entity *se;
7944 tg->cfs_rq = kzalloc(sizeof(cfs_rq) * nr_cpu_ids, GFP_KERNEL);
7947 tg->se = kzalloc(sizeof(se) * nr_cpu_ids, GFP_KERNEL);
7951 tg->shares = NICE_0_LOAD;
7953 for_each_possible_cpu(i) {
7956 cfs_rq = kzalloc_node(sizeof(struct cfs_rq),
7957 GFP_KERNEL, cpu_to_node(i));
7961 se = kzalloc_node(sizeof(struct sched_entity),
7962 GFP_KERNEL, cpu_to_node(i));
7966 init_tg_cfs_entry(tg, cfs_rq, se, i, 0, parent->se[i]);
7977 static inline void register_fair_sched_group(struct task_group *tg, int cpu)
7979 list_add_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list,
7980 &cpu_rq(cpu)->leaf_cfs_rq_list);
7983 static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
7985 list_del_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list);
7987 #else /* !CONFG_FAIR_GROUP_SCHED */
7988 static inline void free_fair_sched_group(struct task_group *tg)
7993 int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
7998 static inline void register_fair_sched_group(struct task_group *tg, int cpu)
8002 static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
8005 #endif /* CONFIG_FAIR_GROUP_SCHED */
8007 #ifdef CONFIG_RT_GROUP_SCHED
8008 static void free_rt_sched_group(struct task_group *tg)
8012 destroy_rt_bandwidth(&tg->rt_bandwidth);
8014 for_each_possible_cpu(i) {
8016 kfree(tg->rt_rq[i]);
8018 kfree(tg->rt_se[i]);
8026 int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
8028 struct rt_rq *rt_rq;
8029 struct sched_rt_entity *rt_se;
8033 tg->rt_rq = kzalloc(sizeof(rt_rq) * nr_cpu_ids, GFP_KERNEL);
8036 tg->rt_se = kzalloc(sizeof(rt_se) * nr_cpu_ids, GFP_KERNEL);
8040 init_rt_bandwidth(&tg->rt_bandwidth,
8041 ktime_to_ns(def_rt_bandwidth.rt_period), 0);
8043 for_each_possible_cpu(i) {
8046 rt_rq = kzalloc_node(sizeof(struct rt_rq),
8047 GFP_KERNEL, cpu_to_node(i));
8051 rt_se = kzalloc_node(sizeof(struct sched_rt_entity),
8052 GFP_KERNEL, cpu_to_node(i));
8056 init_tg_rt_entry(tg, rt_rq, rt_se, i, 0, parent->rt_se[i]);
8067 static inline void register_rt_sched_group(struct task_group *tg, int cpu)
8069 list_add_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list,
8070 &cpu_rq(cpu)->leaf_rt_rq_list);
8073 static inline void unregister_rt_sched_group(struct task_group *tg, int cpu)
8075 list_del_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list);
8077 #else /* !CONFIG_RT_GROUP_SCHED */
8078 static inline void free_rt_sched_group(struct task_group *tg)
8083 int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
8088 static inline void register_rt_sched_group(struct task_group *tg, int cpu)
8092 static inline void unregister_rt_sched_group(struct task_group *tg, int cpu)
8095 #endif /* CONFIG_RT_GROUP_SCHED */
8097 #ifdef CONFIG_CGROUP_SCHED
8098 static void free_sched_group(struct task_group *tg)
8100 free_fair_sched_group(tg);
8101 free_rt_sched_group(tg);
8105 /* allocate runqueue etc for a new task group */
8106 struct task_group *sched_create_group(struct task_group *parent)
8108 struct task_group *tg;
8109 unsigned long flags;
8112 tg = kzalloc(sizeof(*tg), GFP_KERNEL);
8114 return ERR_PTR(-ENOMEM);
8116 if (!alloc_fair_sched_group(tg, parent))
8119 if (!alloc_rt_sched_group(tg, parent))
8122 spin_lock_irqsave(&task_group_lock, flags);
8123 for_each_possible_cpu(i) {
8124 register_fair_sched_group(tg, i);
8125 register_rt_sched_group(tg, i);
8127 list_add_rcu(&tg->list, &task_groups);
8129 WARN_ON(!parent); /* root should already exist */
8131 tg->parent = parent;
8132 INIT_LIST_HEAD(&tg->children);
8133 list_add_rcu(&tg->siblings, &parent->children);
8134 spin_unlock_irqrestore(&task_group_lock, flags);
8139 free_sched_group(tg);
8140 return ERR_PTR(-ENOMEM);
8143 /* rcu callback to free various structures associated with a task group */
8144 static void free_sched_group_rcu(struct rcu_head *rhp)
8146 /* now it should be safe to free those cfs_rqs */
8147 free_sched_group(container_of(rhp, struct task_group, rcu));
8150 /* Destroy runqueue etc associated with a task group */
8151 void sched_destroy_group(struct task_group *tg)
8153 unsigned long flags;
8156 spin_lock_irqsave(&task_group_lock, flags);
8157 for_each_possible_cpu(i) {
8158 unregister_fair_sched_group(tg, i);
8159 unregister_rt_sched_group(tg, i);
8161 list_del_rcu(&tg->list);
8162 list_del_rcu(&tg->siblings);
8163 spin_unlock_irqrestore(&task_group_lock, flags);
8165 /* wait for possible concurrent references to cfs_rqs complete */
8166 call_rcu(&tg->rcu, free_sched_group_rcu);
8169 /* change task's runqueue when it moves between groups.
8170 * The caller of this function should have put the task in its new group
8171 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
8172 * reflect its new group.
8174 void sched_move_task(struct task_struct *tsk)
8177 unsigned long flags;
8180 rq = task_rq_lock(tsk, &flags);
8182 running = task_current(rq, tsk);
8183 on_rq = tsk->se.on_rq;
8186 dequeue_task(rq, tsk, 0);
8187 if (unlikely(running))
8188 tsk->sched_class->put_prev_task(rq, tsk);
8190 set_task_rq(tsk, task_cpu(tsk));
8192 #ifdef CONFIG_FAIR_GROUP_SCHED
8193 if (tsk->sched_class->moved_group)
8194 tsk->sched_class->moved_group(tsk, on_rq);
8197 if (unlikely(running))
8198 tsk->sched_class->set_curr_task(rq);
8200 enqueue_task(rq, tsk, 0, false);
8202 task_rq_unlock(rq, &flags);
8204 #endif /* CONFIG_CGROUP_SCHED */
8206 #ifdef CONFIG_FAIR_GROUP_SCHED
8207 static void __set_se_shares(struct sched_entity *se, unsigned long shares)
8209 struct cfs_rq *cfs_rq = se->cfs_rq;
8214 dequeue_entity(cfs_rq, se, 0);
8216 se->load.weight = shares;
8217 se->load.inv_weight = 0;
8220 enqueue_entity(cfs_rq, se, 0);
8223 static void set_se_shares(struct sched_entity *se, unsigned long shares)
8225 struct cfs_rq *cfs_rq = se->cfs_rq;
8226 struct rq *rq = cfs_rq->rq;
8227 unsigned long flags;
8229 raw_spin_lock_irqsave(&rq->lock, flags);
8230 __set_se_shares(se, shares);
8231 raw_spin_unlock_irqrestore(&rq->lock, flags);
8234 static DEFINE_MUTEX(shares_mutex);
8236 int sched_group_set_shares(struct task_group *tg, unsigned long shares)
8239 unsigned long flags;
8242 * We can't change the weight of the root cgroup.
8247 if (shares < MIN_SHARES)
8248 shares = MIN_SHARES;
8249 else if (shares > MAX_SHARES)
8250 shares = MAX_SHARES;
8252 mutex_lock(&shares_mutex);
8253 if (tg->shares == shares)
8256 spin_lock_irqsave(&task_group_lock, flags);
8257 for_each_possible_cpu(i)
8258 unregister_fair_sched_group(tg, i);
8259 list_del_rcu(&tg->siblings);
8260 spin_unlock_irqrestore(&task_group_lock, flags);
8262 /* wait for any ongoing reference to this group to finish */
8263 synchronize_sched();
8266 * Now we are free to modify the group's share on each cpu
8267 * w/o tripping rebalance_share or load_balance_fair.
8269 tg->shares = shares;
8270 for_each_possible_cpu(i) {
8274 cfs_rq_set_shares(tg->cfs_rq[i], 0);
8275 set_se_shares(tg->se[i], shares);
8279 * Enable load balance activity on this group, by inserting it back on
8280 * each cpu's rq->leaf_cfs_rq_list.
8282 spin_lock_irqsave(&task_group_lock, flags);
8283 for_each_possible_cpu(i)
8284 register_fair_sched_group(tg, i);
8285 list_add_rcu(&tg->siblings, &tg->parent->children);
8286 spin_unlock_irqrestore(&task_group_lock, flags);
8288 mutex_unlock(&shares_mutex);
8292 unsigned long sched_group_shares(struct task_group *tg)
8298 #ifdef CONFIG_RT_GROUP_SCHED
8300 * Ensure that the real time constraints are schedulable.
8302 static DEFINE_MUTEX(rt_constraints_mutex);
8304 static unsigned long to_ratio(u64 period, u64 runtime)
8306 if (runtime == RUNTIME_INF)
8309 return div64_u64(runtime << 20, period);
8312 /* Must be called with tasklist_lock held */
8313 static inline int tg_has_rt_tasks(struct task_group *tg)
8315 struct task_struct *g, *p;
8317 do_each_thread(g, p) {
8318 if (rt_task(p) && rt_rq_of_se(&p->rt)->tg == tg)
8320 } while_each_thread(g, p);
8325 struct rt_schedulable_data {
8326 struct task_group *tg;
8331 static int tg_schedulable(struct task_group *tg, void *data)
8333 struct rt_schedulable_data *d = data;
8334 struct task_group *child;
8335 unsigned long total, sum = 0;
8336 u64 period, runtime;
8338 period = ktime_to_ns(tg->rt_bandwidth.rt_period);
8339 runtime = tg->rt_bandwidth.rt_runtime;
8342 period = d->rt_period;
8343 runtime = d->rt_runtime;
8347 * Cannot have more runtime than the period.
8349 if (runtime > period && runtime != RUNTIME_INF)
8353 * Ensure we don't starve existing RT tasks.
8355 if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg))
8358 total = to_ratio(period, runtime);
8361 * Nobody can have more than the global setting allows.
8363 if (total > to_ratio(global_rt_period(), global_rt_runtime()))
8367 * The sum of our children's runtime should not exceed our own.
8369 list_for_each_entry_rcu(child, &tg->children, siblings) {
8370 period = ktime_to_ns(child->rt_bandwidth.rt_period);
8371 runtime = child->rt_bandwidth.rt_runtime;
8373 if (child == d->tg) {
8374 period = d->rt_period;
8375 runtime = d->rt_runtime;
8378 sum += to_ratio(period, runtime);
8387 static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
8389 struct rt_schedulable_data data = {
8391 .rt_period = period,
8392 .rt_runtime = runtime,
8395 return walk_tg_tree(tg_schedulable, tg_nop, &data);
8398 static int tg_set_bandwidth(struct task_group *tg,
8399 u64 rt_period, u64 rt_runtime)
8403 mutex_lock(&rt_constraints_mutex);
8404 read_lock(&tasklist_lock);
8405 err = __rt_schedulable(tg, rt_period, rt_runtime);
8409 raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock);
8410 tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period);
8411 tg->rt_bandwidth.rt_runtime = rt_runtime;
8413 for_each_possible_cpu(i) {
8414 struct rt_rq *rt_rq = tg->rt_rq[i];
8416 raw_spin_lock(&rt_rq->rt_runtime_lock);
8417 rt_rq->rt_runtime = rt_runtime;
8418 raw_spin_unlock(&rt_rq->rt_runtime_lock);
8420 raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock);
8422 read_unlock(&tasklist_lock);
8423 mutex_unlock(&rt_constraints_mutex);
8428 int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us)
8430 u64 rt_runtime, rt_period;
8432 rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period);
8433 rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC;
8434 if (rt_runtime_us < 0)
8435 rt_runtime = RUNTIME_INF;
8437 return tg_set_bandwidth(tg, rt_period, rt_runtime);
8440 long sched_group_rt_runtime(struct task_group *tg)
8444 if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF)
8447 rt_runtime_us = tg->rt_bandwidth.rt_runtime;
8448 do_div(rt_runtime_us, NSEC_PER_USEC);
8449 return rt_runtime_us;
8452 int sched_group_set_rt_period(struct task_group *tg, long rt_period_us)
8454 u64 rt_runtime, rt_period;
8456 rt_period = (u64)rt_period_us * NSEC_PER_USEC;
8457 rt_runtime = tg->rt_bandwidth.rt_runtime;
8462 return tg_set_bandwidth(tg, rt_period, rt_runtime);
8465 long sched_group_rt_period(struct task_group *tg)
8469 rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period);
8470 do_div(rt_period_us, NSEC_PER_USEC);
8471 return rt_period_us;
8474 static int sched_rt_global_constraints(void)
8476 u64 runtime, period;
8479 if (sysctl_sched_rt_period <= 0)
8482 runtime = global_rt_runtime();
8483 period = global_rt_period();
8486 * Sanity check on the sysctl variables.
8488 if (runtime > period && runtime != RUNTIME_INF)
8491 mutex_lock(&rt_constraints_mutex);
8492 read_lock(&tasklist_lock);
8493 ret = __rt_schedulable(NULL, 0, 0);
8494 read_unlock(&tasklist_lock);
8495 mutex_unlock(&rt_constraints_mutex);
8500 int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk)
8502 /* Don't accept realtime tasks when there is no way for them to run */
8503 if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0)
8509 #else /* !CONFIG_RT_GROUP_SCHED */
8510 static int sched_rt_global_constraints(void)
8512 unsigned long flags;
8515 if (sysctl_sched_rt_period <= 0)
8519 * There's always some RT tasks in the root group
8520 * -- migration, kstopmachine etc..
8522 if (sysctl_sched_rt_runtime == 0)
8525 raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
8526 for_each_possible_cpu(i) {
8527 struct rt_rq *rt_rq = &cpu_rq(i)->rt;
8529 raw_spin_lock(&rt_rq->rt_runtime_lock);
8530 rt_rq->rt_runtime = global_rt_runtime();
8531 raw_spin_unlock(&rt_rq->rt_runtime_lock);
8533 raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags);
8537 #endif /* CONFIG_RT_GROUP_SCHED */
8539 int sched_rt_handler(struct ctl_table *table, int write,
8540 void __user *buffer, size_t *lenp,
8544 int old_period, old_runtime;
8545 static DEFINE_MUTEX(mutex);
8548 old_period = sysctl_sched_rt_period;
8549 old_runtime = sysctl_sched_rt_runtime;
8551 ret = proc_dointvec(table, write, buffer, lenp, ppos);
8553 if (!ret && write) {
8554 ret = sched_rt_global_constraints();
8556 sysctl_sched_rt_period = old_period;
8557 sysctl_sched_rt_runtime = old_runtime;
8559 def_rt_bandwidth.rt_runtime = global_rt_runtime();
8560 def_rt_bandwidth.rt_period =
8561 ns_to_ktime(global_rt_period());
8564 mutex_unlock(&mutex);
8569 #ifdef CONFIG_CGROUP_SCHED
8571 /* return corresponding task_group object of a cgroup */
8572 static inline struct task_group *cgroup_tg(struct cgroup *cgrp)
8574 return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id),
8575 struct task_group, css);
8578 static struct cgroup_subsys_state *
8579 cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp)
8581 struct task_group *tg, *parent;
8583 if (!cgrp->parent) {
8584 /* This is early initialization for the top cgroup */
8585 return &init_task_group.css;
8588 parent = cgroup_tg(cgrp->parent);
8589 tg = sched_create_group(parent);
8591 return ERR_PTR(-ENOMEM);
8597 cpu_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
8599 struct task_group *tg = cgroup_tg(cgrp);
8601 sched_destroy_group(tg);
8605 cpu_cgroup_can_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
8607 #ifdef CONFIG_RT_GROUP_SCHED
8608 if (!sched_rt_can_attach(cgroup_tg(cgrp), tsk))
8611 /* We don't support RT-tasks being in separate groups */
8612 if (tsk->sched_class != &fair_sched_class)
8619 cpu_cgroup_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
8620 struct task_struct *tsk, bool threadgroup)
8622 int retval = cpu_cgroup_can_attach_task(cgrp, tsk);
8626 struct task_struct *c;
8628 list_for_each_entry_rcu(c, &tsk->thread_group, thread_group) {
8629 retval = cpu_cgroup_can_attach_task(cgrp, c);
8641 cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
8642 struct cgroup *old_cont, struct task_struct *tsk,
8645 sched_move_task(tsk);
8647 struct task_struct *c;
8649 list_for_each_entry_rcu(c, &tsk->thread_group, thread_group) {
8656 #ifdef CONFIG_FAIR_GROUP_SCHED
8657 static int cpu_shares_write_u64(struct cgroup *cgrp, struct cftype *cftype,
8660 return sched_group_set_shares(cgroup_tg(cgrp), shareval);
8663 static u64 cpu_shares_read_u64(struct cgroup *cgrp, struct cftype *cft)
8665 struct task_group *tg = cgroup_tg(cgrp);
8667 return (u64) tg->shares;
8669 #endif /* CONFIG_FAIR_GROUP_SCHED */
8671 #ifdef CONFIG_RT_GROUP_SCHED
8672 static int cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft,
8675 return sched_group_set_rt_runtime(cgroup_tg(cgrp), val);
8678 static s64 cpu_rt_runtime_read(struct cgroup *cgrp, struct cftype *cft)
8680 return sched_group_rt_runtime(cgroup_tg(cgrp));
8683 static int cpu_rt_period_write_uint(struct cgroup *cgrp, struct cftype *cftype,
8686 return sched_group_set_rt_period(cgroup_tg(cgrp), rt_period_us);
8689 static u64 cpu_rt_period_read_uint(struct cgroup *cgrp, struct cftype *cft)
8691 return sched_group_rt_period(cgroup_tg(cgrp));
8693 #endif /* CONFIG_RT_GROUP_SCHED */
8695 static struct cftype cpu_files[] = {
8696 #ifdef CONFIG_FAIR_GROUP_SCHED
8699 .read_u64 = cpu_shares_read_u64,
8700 .write_u64 = cpu_shares_write_u64,
8703 #ifdef CONFIG_RT_GROUP_SCHED
8705 .name = "rt_runtime_us",
8706 .read_s64 = cpu_rt_runtime_read,
8707 .write_s64 = cpu_rt_runtime_write,
8710 .name = "rt_period_us",
8711 .read_u64 = cpu_rt_period_read_uint,
8712 .write_u64 = cpu_rt_period_write_uint,
8717 static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont)
8719 return cgroup_add_files(cont, ss, cpu_files, ARRAY_SIZE(cpu_files));
8722 struct cgroup_subsys cpu_cgroup_subsys = {
8724 .create = cpu_cgroup_create,
8725 .destroy = cpu_cgroup_destroy,
8726 .can_attach = cpu_cgroup_can_attach,
8727 .attach = cpu_cgroup_attach,
8728 .populate = cpu_cgroup_populate,
8729 .subsys_id = cpu_cgroup_subsys_id,
8733 #endif /* CONFIG_CGROUP_SCHED */
8735 #ifdef CONFIG_CGROUP_CPUACCT
8738 * CPU accounting code for task groups.
8740 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
8741 * (balbir@in.ibm.com).
8744 /* track cpu usage of a group of tasks and its child groups */
8746 struct cgroup_subsys_state css;
8747 /* cpuusage holds pointer to a u64-type object on every cpu */
8748 u64 __percpu *cpuusage;
8749 struct percpu_counter cpustat[CPUACCT_STAT_NSTATS];
8750 struct cpuacct *parent;
8753 struct cgroup_subsys cpuacct_subsys;
8755 /* return cpu accounting group corresponding to this container */
8756 static inline struct cpuacct *cgroup_ca(struct cgroup *cgrp)
8758 return container_of(cgroup_subsys_state(cgrp, cpuacct_subsys_id),
8759 struct cpuacct, css);
8762 /* return cpu accounting group to which this task belongs */
8763 static inline struct cpuacct *task_ca(struct task_struct *tsk)
8765 return container_of(task_subsys_state(tsk, cpuacct_subsys_id),
8766 struct cpuacct, css);
8769 /* create a new cpu accounting group */
8770 static struct cgroup_subsys_state *cpuacct_create(
8771 struct cgroup_subsys *ss, struct cgroup *cgrp)
8773 struct cpuacct *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
8779 ca->cpuusage = alloc_percpu(u64);
8783 for (i = 0; i < CPUACCT_STAT_NSTATS; i++)
8784 if (percpu_counter_init(&ca->cpustat[i], 0))
8785 goto out_free_counters;
8788 ca->parent = cgroup_ca(cgrp->parent);
8794 percpu_counter_destroy(&ca->cpustat[i]);
8795 free_percpu(ca->cpuusage);
8799 return ERR_PTR(-ENOMEM);
8802 /* destroy an existing cpu accounting group */
8804 cpuacct_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
8806 struct cpuacct *ca = cgroup_ca(cgrp);
8809 for (i = 0; i < CPUACCT_STAT_NSTATS; i++)
8810 percpu_counter_destroy(&ca->cpustat[i]);
8811 free_percpu(ca->cpuusage);
8815 static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu)
8817 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
8820 #ifndef CONFIG_64BIT
8822 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
8824 raw_spin_lock_irq(&cpu_rq(cpu)->lock);
8826 raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
8834 static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val)
8836 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
8838 #ifndef CONFIG_64BIT
8840 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
8842 raw_spin_lock_irq(&cpu_rq(cpu)->lock);
8844 raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
8850 /* return total cpu usage (in nanoseconds) of a group */
8851 static u64 cpuusage_read(struct cgroup *cgrp, struct cftype *cft)
8853 struct cpuacct *ca = cgroup_ca(cgrp);
8854 u64 totalcpuusage = 0;
8857 for_each_present_cpu(i)
8858 totalcpuusage += cpuacct_cpuusage_read(ca, i);
8860 return totalcpuusage;
8863 static int cpuusage_write(struct cgroup *cgrp, struct cftype *cftype,
8866 struct cpuacct *ca = cgroup_ca(cgrp);
8875 for_each_present_cpu(i)
8876 cpuacct_cpuusage_write(ca, i, 0);
8882 static int cpuacct_percpu_seq_read(struct cgroup *cgroup, struct cftype *cft,
8885 struct cpuacct *ca = cgroup_ca(cgroup);
8889 for_each_present_cpu(i) {
8890 percpu = cpuacct_cpuusage_read(ca, i);
8891 seq_printf(m, "%llu ", (unsigned long long) percpu);
8893 seq_printf(m, "\n");
8897 static const char *cpuacct_stat_desc[] = {
8898 [CPUACCT_STAT_USER] = "user",
8899 [CPUACCT_STAT_SYSTEM] = "system",
8902 static int cpuacct_stats_show(struct cgroup *cgrp, struct cftype *cft,
8903 struct cgroup_map_cb *cb)
8905 struct cpuacct *ca = cgroup_ca(cgrp);
8908 for (i = 0; i < CPUACCT_STAT_NSTATS; i++) {
8909 s64 val = percpu_counter_read(&ca->cpustat[i]);
8910 val = cputime64_to_clock_t(val);
8911 cb->fill(cb, cpuacct_stat_desc[i], val);
8916 static struct cftype files[] = {
8919 .read_u64 = cpuusage_read,
8920 .write_u64 = cpuusage_write,
8923 .name = "usage_percpu",
8924 .read_seq_string = cpuacct_percpu_seq_read,
8928 .read_map = cpuacct_stats_show,
8932 static int cpuacct_populate(struct cgroup_subsys *ss, struct cgroup *cgrp)
8934 return cgroup_add_files(cgrp, ss, files, ARRAY_SIZE(files));
8938 * charge this task's execution time to its accounting group.
8940 * called with rq->lock held.
8942 static void cpuacct_charge(struct task_struct *tsk, u64 cputime)
8947 if (unlikely(!cpuacct_subsys.active))
8950 cpu = task_cpu(tsk);
8956 for (; ca; ca = ca->parent) {
8957 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
8958 *cpuusage += cputime;
8965 * When CONFIG_VIRT_CPU_ACCOUNTING is enabled one jiffy can be very large
8966 * in cputime_t units. As a result, cpuacct_update_stats calls
8967 * percpu_counter_add with values large enough to always overflow the
8968 * per cpu batch limit causing bad SMP scalability.
8970 * To fix this we scale percpu_counter_batch by cputime_one_jiffy so we
8971 * batch the same amount of time with CONFIG_VIRT_CPU_ACCOUNTING disabled
8972 * and enabled. We cap it at INT_MAX which is the largest allowed batch value.
8975 #define CPUACCT_BATCH \
8976 min_t(long, percpu_counter_batch * cputime_one_jiffy, INT_MAX)
8978 #define CPUACCT_BATCH 0
8982 * Charge the system/user time to the task's accounting group.
8984 static void cpuacct_update_stats(struct task_struct *tsk,
8985 enum cpuacct_stat_index idx, cputime_t val)
8988 int batch = CPUACCT_BATCH;
8990 if (unlikely(!cpuacct_subsys.active))
8997 __percpu_counter_add(&ca->cpustat[idx], val, batch);
9003 struct cgroup_subsys cpuacct_subsys = {
9005 .create = cpuacct_create,
9006 .destroy = cpuacct_destroy,
9007 .populate = cpuacct_populate,
9008 .subsys_id = cpuacct_subsys_id,
9010 #endif /* CONFIG_CGROUP_CPUACCT */
9014 int rcu_expedited_torture_stats(char *page)
9018 EXPORT_SYMBOL_GPL(rcu_expedited_torture_stats);
9020 void synchronize_sched_expedited(void)
9023 EXPORT_SYMBOL_GPL(synchronize_sched_expedited);
9025 #else /* #ifndef CONFIG_SMP */
9027 static DEFINE_PER_CPU(struct migration_req, rcu_migration_req);
9028 static DEFINE_MUTEX(rcu_sched_expedited_mutex);
9030 #define RCU_EXPEDITED_STATE_POST -2
9031 #define RCU_EXPEDITED_STATE_IDLE -1
9033 static int rcu_expedited_state = RCU_EXPEDITED_STATE_IDLE;
9035 int rcu_expedited_torture_stats(char *page)
9040 cnt += sprintf(&page[cnt], "state: %d /", rcu_expedited_state);
9041 for_each_online_cpu(cpu) {
9042 cnt += sprintf(&page[cnt], " %d:%d",
9043 cpu, per_cpu(rcu_migration_req, cpu).dest_cpu);
9045 cnt += sprintf(&page[cnt], "\n");
9048 EXPORT_SYMBOL_GPL(rcu_expedited_torture_stats);
9050 static long synchronize_sched_expedited_count;
9053 * Wait for an rcu-sched grace period to elapse, but use "big hammer"
9054 * approach to force grace period to end quickly. This consumes
9055 * significant time on all CPUs, and is thus not recommended for
9056 * any sort of common-case code.
9058 * Note that it is illegal to call this function while holding any
9059 * lock that is acquired by a CPU-hotplug notifier. Failing to
9060 * observe this restriction will result in deadlock.
9062 void synchronize_sched_expedited(void)
9065 unsigned long flags;
9066 bool need_full_sync = 0;
9068 struct migration_req *req;
9072 smp_mb(); /* ensure prior mod happens before capturing snap. */
9073 snap = ACCESS_ONCE(synchronize_sched_expedited_count) + 1;
9075 while (!mutex_trylock(&rcu_sched_expedited_mutex)) {
9077 if (trycount++ < 10)
9078 udelay(trycount * num_online_cpus());
9080 synchronize_sched();
9083 if (ACCESS_ONCE(synchronize_sched_expedited_count) - snap > 0) {
9084 smp_mb(); /* ensure test happens before caller kfree */
9089 rcu_expedited_state = RCU_EXPEDITED_STATE_POST;
9090 for_each_online_cpu(cpu) {
9092 req = &per_cpu(rcu_migration_req, cpu);
9093 init_completion(&req->done);
9095 req->dest_cpu = RCU_MIGRATION_NEED_QS;
9096 raw_spin_lock_irqsave(&rq->lock, flags);
9097 list_add(&req->list, &rq->migration_queue);
9098 raw_spin_unlock_irqrestore(&rq->lock, flags);
9099 wake_up_process(rq->migration_thread);
9101 for_each_online_cpu(cpu) {
9102 rcu_expedited_state = cpu;
9103 req = &per_cpu(rcu_migration_req, cpu);
9105 wait_for_completion(&req->done);
9106 raw_spin_lock_irqsave(&rq->lock, flags);
9107 if (unlikely(req->dest_cpu == RCU_MIGRATION_MUST_SYNC))
9109 req->dest_cpu = RCU_MIGRATION_IDLE;
9110 raw_spin_unlock_irqrestore(&rq->lock, flags);
9112 rcu_expedited_state = RCU_EXPEDITED_STATE_IDLE;
9113 synchronize_sched_expedited_count++;
9114 mutex_unlock(&rcu_sched_expedited_mutex);
9117 synchronize_sched();
9119 EXPORT_SYMBOL_GPL(synchronize_sched_expedited);
9121 #endif /* #else #ifndef CONFIG_SMP */