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 <asm/mmu_context.h>
36 #include <linux/interrupt.h>
37 #include <linux/capability.h>
38 #include <linux/completion.h>
39 #include <linux/kernel_stat.h>
40 #include <linux/debug_locks.h>
41 #include <linux/perf_event.h>
42 #include <linux/security.h>
43 #include <linux/notifier.h>
44 #include <linux/profile.h>
45 #include <linux/freezer.h>
46 #include <linux/vmalloc.h>
47 #include <linux/blkdev.h>
48 #include <linux/delay.h>
49 #include <linux/pid_namespace.h>
50 #include <linux/smp.h>
51 #include <linux/threads.h>
52 #include <linux/timer.h>
53 #include <linux/rcupdate.h>
54 #include <linux/cpu.h>
55 #include <linux/cpuset.h>
56 #include <linux/percpu.h>
57 #include <linux/proc_fs.h>
58 #include <linux/seq_file.h>
59 #include <linux/stop_machine.h>
60 #include <linux/sysctl.h>
61 #include <linux/syscalls.h>
62 #include <linux/times.h>
63 #include <linux/tsacct_kern.h>
64 #include <linux/kprobes.h>
65 #include <linux/delayacct.h>
66 #include <linux/unistd.h>
67 #include <linux/pagemap.h>
68 #include <linux/hrtimer.h>
69 #include <linux/tick.h>
70 #include <linux/debugfs.h>
71 #include <linux/ctype.h>
72 #include <linux/ftrace.h>
73 #include <linux/slab.h>
76 #include <asm/irq_regs.h>
77 #include <asm/mutex.h>
79 #include "sched_cpupri.h"
80 #include "workqueue_sched.h"
81 #include "sched_autogroup.h"
83 #define CREATE_TRACE_POINTS
84 #include <trace/events/sched.h>
87 * Convert user-nice values [ -20 ... 0 ... 19 ]
88 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
91 #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
92 #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
93 #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
96 * 'User priority' is the nice value converted to something we
97 * can work with better when scaling various scheduler parameters,
98 * it's a [ 0 ... 39 ] range.
100 #define USER_PRIO(p) ((p)-MAX_RT_PRIO)
101 #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
102 #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
105 * Helpers for converting nanosecond timing to jiffy resolution
107 #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
109 #define NICE_0_LOAD SCHED_LOAD_SCALE
110 #define NICE_0_SHIFT SCHED_LOAD_SHIFT
113 * These are the 'tuning knobs' of the scheduler:
115 * default timeslice is 100 msecs (used only for SCHED_RR tasks).
116 * Timeslices get refilled after they expire.
118 #define DEF_TIMESLICE (100 * HZ / 1000)
121 * single value that denotes runtime == period, ie unlimited time.
123 #define RUNTIME_INF ((u64)~0ULL)
125 static inline int rt_policy(int policy)
127 if (unlikely(policy == SCHED_FIFO || policy == SCHED_RR))
132 static inline int task_has_rt_policy(struct task_struct *p)
134 return rt_policy(p->policy);
138 * This is the priority-queue data structure of the RT scheduling class:
140 struct rt_prio_array {
141 DECLARE_BITMAP(bitmap, MAX_RT_PRIO+1); /* include 1 bit for delimiter */
142 struct list_head queue[MAX_RT_PRIO];
145 struct rt_bandwidth {
146 /* nests inside the rq lock: */
147 raw_spinlock_t rt_runtime_lock;
150 struct hrtimer rt_period_timer;
153 static struct rt_bandwidth def_rt_bandwidth;
155 static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun);
157 static enum hrtimer_restart sched_rt_period_timer(struct hrtimer *timer)
159 struct rt_bandwidth *rt_b =
160 container_of(timer, struct rt_bandwidth, rt_period_timer);
166 now = hrtimer_cb_get_time(timer);
167 overrun = hrtimer_forward(timer, now, rt_b->rt_period);
172 idle = do_sched_rt_period_timer(rt_b, overrun);
175 return idle ? HRTIMER_NORESTART : HRTIMER_RESTART;
179 void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime)
181 rt_b->rt_period = ns_to_ktime(period);
182 rt_b->rt_runtime = runtime;
184 raw_spin_lock_init(&rt_b->rt_runtime_lock);
186 hrtimer_init(&rt_b->rt_period_timer,
187 CLOCK_MONOTONIC, HRTIMER_MODE_REL);
188 rt_b->rt_period_timer.function = sched_rt_period_timer;
191 static inline int rt_bandwidth_enabled(void)
193 return sysctl_sched_rt_runtime >= 0;
196 static void start_rt_bandwidth(struct rt_bandwidth *rt_b)
200 if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)
203 if (hrtimer_active(&rt_b->rt_period_timer))
206 raw_spin_lock(&rt_b->rt_runtime_lock);
211 if (hrtimer_active(&rt_b->rt_period_timer))
214 now = hrtimer_cb_get_time(&rt_b->rt_period_timer);
215 hrtimer_forward(&rt_b->rt_period_timer, now, rt_b->rt_period);
217 soft = hrtimer_get_softexpires(&rt_b->rt_period_timer);
218 hard = hrtimer_get_expires(&rt_b->rt_period_timer);
219 delta = ktime_to_ns(ktime_sub(hard, soft));
220 __hrtimer_start_range_ns(&rt_b->rt_period_timer, soft, delta,
221 HRTIMER_MODE_ABS_PINNED, 0);
223 raw_spin_unlock(&rt_b->rt_runtime_lock);
226 #ifdef CONFIG_RT_GROUP_SCHED
227 static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b)
229 hrtimer_cancel(&rt_b->rt_period_timer);
234 * sched_domains_mutex serializes calls to init_sched_domains,
235 * detach_destroy_domains and partition_sched_domains.
237 static DEFINE_MUTEX(sched_domains_mutex);
239 #ifdef CONFIG_CGROUP_SCHED
241 #include <linux/cgroup.h>
245 static LIST_HEAD(task_groups);
247 /* task group related information */
249 struct cgroup_subsys_state css;
251 #ifdef CONFIG_FAIR_GROUP_SCHED
252 /* schedulable entities of this group on each cpu */
253 struct sched_entity **se;
254 /* runqueue "owned" by this group on each cpu */
255 struct cfs_rq **cfs_rq;
256 unsigned long shares;
258 atomic_t load_weight;
261 #ifdef CONFIG_RT_GROUP_SCHED
262 struct sched_rt_entity **rt_se;
263 struct rt_rq **rt_rq;
265 struct rt_bandwidth rt_bandwidth;
269 struct list_head list;
271 struct task_group *parent;
272 struct list_head siblings;
273 struct list_head children;
275 #ifdef CONFIG_SCHED_AUTOGROUP
276 struct autogroup *autogroup;
280 /* task_group_lock serializes the addition/removal of task groups */
281 static DEFINE_SPINLOCK(task_group_lock);
283 #ifdef CONFIG_FAIR_GROUP_SCHED
285 # define ROOT_TASK_GROUP_LOAD NICE_0_LOAD
288 * A weight of 0 or 1 can cause arithmetics problems.
289 * A weight of a cfs_rq is the sum of weights of which entities
290 * are queued on this cfs_rq, so a weight of a entity should not be
291 * too large, so as the shares value of a task group.
292 * (The default weight is 1024 - so there's no practical
293 * limitation from this.)
296 #define MAX_SHARES (1UL << 18)
298 static int root_task_group_load = ROOT_TASK_GROUP_LOAD;
301 /* Default task group.
302 * Every task in system belong to this group at bootup.
304 struct task_group root_task_group;
306 #endif /* CONFIG_CGROUP_SCHED */
308 /* CFS-related fields in a runqueue */
310 struct load_weight load;
311 unsigned long nr_running;
316 struct rb_root tasks_timeline;
317 struct rb_node *rb_leftmost;
319 struct list_head tasks;
320 struct list_head *balance_iterator;
323 * 'curr' points to currently running entity on this cfs_rq.
324 * It is set to NULL otherwise (i.e when none are currently running).
326 struct sched_entity *curr, *next, *last, *skip;
328 unsigned int nr_spread_over;
330 #ifdef CONFIG_FAIR_GROUP_SCHED
331 struct rq *rq; /* cpu runqueue to which this cfs_rq is attached */
334 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
335 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
336 * (like users, containers etc.)
338 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
339 * list is used during load balance.
342 struct list_head leaf_cfs_rq_list;
343 struct task_group *tg; /* group that "owns" this runqueue */
347 * the part of load.weight contributed by tasks
349 unsigned long task_weight;
352 * h_load = weight * f(tg)
354 * Where f(tg) is the recursive weight fraction assigned to
357 unsigned long h_load;
360 * Maintaining per-cpu shares distribution for group scheduling
362 * load_stamp is the last time we updated the load average
363 * load_last is the last time we updated the load average and saw load
364 * load_unacc_exec_time is currently unaccounted execution time
368 u64 load_stamp, load_last, load_unacc_exec_time;
370 unsigned long load_contribution;
375 /* Real-Time classes' related field in a runqueue: */
377 struct rt_prio_array active;
378 unsigned long rt_nr_running;
379 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
381 int curr; /* highest queued rt task prio */
383 int next; /* next highest */
388 unsigned long rt_nr_migratory;
389 unsigned long rt_nr_total;
391 struct plist_head pushable_tasks;
396 /* Nests inside the rq lock: */
397 raw_spinlock_t rt_runtime_lock;
399 #ifdef CONFIG_RT_GROUP_SCHED
400 unsigned long rt_nr_boosted;
403 struct list_head leaf_rt_rq_list;
404 struct task_group *tg;
411 * We add the notion of a root-domain which will be used to define per-domain
412 * variables. Each exclusive cpuset essentially defines an island domain by
413 * fully partitioning the member cpus from any other cpuset. Whenever a new
414 * exclusive cpuset is created, we also create and attach a new root-domain
422 cpumask_var_t online;
425 * The "RT overload" flag: it gets set if a CPU has more than
426 * one runnable RT task.
428 cpumask_var_t rto_mask;
430 struct cpupri cpupri;
434 * By default the system creates a single root-domain with all cpus as
435 * members (mimicking the global state we have today).
437 static struct root_domain def_root_domain;
439 #endif /* CONFIG_SMP */
442 * This is the main, per-CPU runqueue data structure.
444 * Locking rule: those places that want to lock multiple runqueues
445 * (such as the load balancing or the thread migration code), lock
446 * acquire operations must be ordered by ascending &runqueue.
453 * nr_running and cpu_load should be in the same cacheline because
454 * remote CPUs use both these fields when doing load calculation.
456 unsigned long nr_running;
457 #define CPU_LOAD_IDX_MAX 5
458 unsigned long cpu_load[CPU_LOAD_IDX_MAX];
459 unsigned long last_load_update_tick;
462 unsigned char nohz_balance_kick;
464 unsigned int skip_clock_update;
466 /* capture load from *all* tasks on this cpu: */
467 struct load_weight load;
468 unsigned long nr_load_updates;
474 #ifdef CONFIG_FAIR_GROUP_SCHED
475 /* list of leaf cfs_rq on this cpu: */
476 struct list_head leaf_cfs_rq_list;
478 #ifdef CONFIG_RT_GROUP_SCHED
479 struct list_head leaf_rt_rq_list;
483 * This is part of a global counter where only the total sum
484 * over all CPUs matters. A task can increase this counter on
485 * one CPU and if it got migrated afterwards it may decrease
486 * it on another CPU. Always updated under the runqueue lock:
488 unsigned long nr_uninterruptible;
490 struct task_struct *curr, *idle, *stop;
491 unsigned long next_balance;
492 struct mm_struct *prev_mm;
500 struct root_domain *rd;
501 struct sched_domain *sd;
503 unsigned long cpu_power;
505 unsigned char idle_at_tick;
506 /* For active balancing */
510 struct cpu_stop_work active_balance_work;
511 /* cpu of this runqueue: */
515 unsigned long avg_load_per_task;
523 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
527 /* calc_load related fields */
528 unsigned long calc_load_update;
529 long calc_load_active;
531 #ifdef CONFIG_SCHED_HRTICK
533 int hrtick_csd_pending;
534 struct call_single_data hrtick_csd;
536 struct hrtimer hrtick_timer;
539 #ifdef CONFIG_SCHEDSTATS
541 struct sched_info rq_sched_info;
542 unsigned long long rq_cpu_time;
543 /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
545 /* sys_sched_yield() stats */
546 unsigned int yld_count;
548 /* schedule() stats */
549 unsigned int sched_switch;
550 unsigned int sched_count;
551 unsigned int sched_goidle;
553 /* try_to_wake_up() stats */
554 unsigned int ttwu_count;
555 unsigned int ttwu_local;
559 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
562 static void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags);
564 static inline int cpu_of(struct rq *rq)
573 #define rcu_dereference_check_sched_domain(p) \
574 rcu_dereference_check((p), \
575 rcu_read_lock_held() || \
576 lockdep_is_held(&sched_domains_mutex))
579 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
580 * See detach_destroy_domains: synchronize_sched for details.
582 * The domain tree of any CPU may only be accessed from within
583 * preempt-disabled sections.
585 #define for_each_domain(cpu, __sd) \
586 for (__sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
588 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
589 #define this_rq() (&__get_cpu_var(runqueues))
590 #define task_rq(p) cpu_rq(task_cpu(p))
591 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
592 #define raw_rq() (&__raw_get_cpu_var(runqueues))
594 #ifdef CONFIG_CGROUP_SCHED
597 * Return the group to which this tasks belongs.
599 * We use task_subsys_state_check() and extend the RCU verification
600 * with lockdep_is_held(&task_rq(p)->lock) because cpu_cgroup_attach()
601 * holds that lock for each task it moves into the cgroup. Therefore
602 * by holding that lock, we pin the task to the current cgroup.
604 static inline struct task_group *task_group(struct task_struct *p)
606 struct task_group *tg;
607 struct cgroup_subsys_state *css;
609 css = task_subsys_state_check(p, cpu_cgroup_subsys_id,
610 lockdep_is_held(&task_rq(p)->lock));
611 tg = container_of(css, struct task_group, css);
613 return autogroup_task_group(p, tg);
616 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
617 static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
619 #ifdef CONFIG_FAIR_GROUP_SCHED
620 p->se.cfs_rq = task_group(p)->cfs_rq[cpu];
621 p->se.parent = task_group(p)->se[cpu];
624 #ifdef CONFIG_RT_GROUP_SCHED
625 p->rt.rt_rq = task_group(p)->rt_rq[cpu];
626 p->rt.parent = task_group(p)->rt_se[cpu];
630 #else /* CONFIG_CGROUP_SCHED */
632 static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { }
633 static inline struct task_group *task_group(struct task_struct *p)
638 #endif /* CONFIG_CGROUP_SCHED */
640 static void update_rq_clock_task(struct rq *rq, s64 delta);
642 static void update_rq_clock(struct rq *rq)
646 if (rq->skip_clock_update)
649 delta = sched_clock_cpu(cpu_of(rq)) - rq->clock;
651 update_rq_clock_task(rq, delta);
655 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
657 #ifdef CONFIG_SCHED_DEBUG
658 # define const_debug __read_mostly
660 # define const_debug static const
664 * runqueue_is_locked - Returns true if the current cpu runqueue is locked
665 * @cpu: the processor in question.
667 * This interface allows printk to be called with the runqueue lock
668 * held and know whether or not it is OK to wake up the klogd.
670 int runqueue_is_locked(int cpu)
672 return raw_spin_is_locked(&cpu_rq(cpu)->lock);
676 * Debugging: various feature bits
679 #define SCHED_FEAT(name, enabled) \
680 __SCHED_FEAT_##name ,
683 #include "sched_features.h"
688 #define SCHED_FEAT(name, enabled) \
689 (1UL << __SCHED_FEAT_##name) * enabled |
691 const_debug unsigned int sysctl_sched_features =
692 #include "sched_features.h"
697 #ifdef CONFIG_SCHED_DEBUG
698 #define SCHED_FEAT(name, enabled) \
701 static __read_mostly char *sched_feat_names[] = {
702 #include "sched_features.h"
708 static int sched_feat_show(struct seq_file *m, void *v)
712 for (i = 0; sched_feat_names[i]; i++) {
713 if (!(sysctl_sched_features & (1UL << i)))
715 seq_printf(m, "%s ", sched_feat_names[i]);
723 sched_feat_write(struct file *filp, const char __user *ubuf,
724 size_t cnt, loff_t *ppos)
734 if (copy_from_user(&buf, ubuf, cnt))
740 if (strncmp(cmp, "NO_", 3) == 0) {
745 for (i = 0; sched_feat_names[i]; i++) {
746 if (strcmp(cmp, sched_feat_names[i]) == 0) {
748 sysctl_sched_features &= ~(1UL << i);
750 sysctl_sched_features |= (1UL << i);
755 if (!sched_feat_names[i])
763 static int sched_feat_open(struct inode *inode, struct file *filp)
765 return single_open(filp, sched_feat_show, NULL);
768 static const struct file_operations sched_feat_fops = {
769 .open = sched_feat_open,
770 .write = sched_feat_write,
773 .release = single_release,
776 static __init int sched_init_debug(void)
778 debugfs_create_file("sched_features", 0644, NULL, NULL,
783 late_initcall(sched_init_debug);
787 #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
790 * Number of tasks to iterate in a single balance run.
791 * Limited because this is done with IRQs disabled.
793 const_debug unsigned int sysctl_sched_nr_migrate = 32;
796 * period over which we average the RT time consumption, measured
801 const_debug unsigned int sysctl_sched_time_avg = MSEC_PER_SEC;
804 * period over which we measure -rt task cpu usage in us.
807 unsigned int sysctl_sched_rt_period = 1000000;
809 static __read_mostly int scheduler_running;
812 * part of the period that we allow rt tasks to run in us.
815 int sysctl_sched_rt_runtime = 950000;
817 static inline u64 global_rt_period(void)
819 return (u64)sysctl_sched_rt_period * NSEC_PER_USEC;
822 static inline u64 global_rt_runtime(void)
824 if (sysctl_sched_rt_runtime < 0)
827 return (u64)sysctl_sched_rt_runtime * NSEC_PER_USEC;
830 #ifndef prepare_arch_switch
831 # define prepare_arch_switch(next) do { } while (0)
833 #ifndef finish_arch_switch
834 # define finish_arch_switch(prev) do { } while (0)
837 static inline int task_current(struct rq *rq, struct task_struct *p)
839 return rq->curr == p;
842 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
843 static inline int task_running(struct rq *rq, struct task_struct *p)
845 return task_current(rq, p);
848 static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
852 static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
854 #ifdef CONFIG_DEBUG_SPINLOCK
855 /* this is a valid case when another task releases the spinlock */
856 rq->lock.owner = current;
859 * If we are tracking spinlock dependencies then we have to
860 * fix up the runqueue lock - which gets 'carried over' from
863 spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_);
865 raw_spin_unlock_irq(&rq->lock);
868 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
869 static inline int task_running(struct rq *rq, struct task_struct *p)
874 return task_current(rq, p);
878 static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
882 * We can optimise this out completely for !SMP, because the
883 * SMP rebalancing from interrupt is the only thing that cares
888 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
889 raw_spin_unlock_irq(&rq->lock);
891 raw_spin_unlock(&rq->lock);
895 static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
899 * After ->oncpu is cleared, the task can be moved to a different CPU.
900 * We must ensure this doesn't happen until the switch is completely
906 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
910 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
913 * Check whether the task is waking, we use this to synchronize ->cpus_allowed
916 static inline int task_is_waking(struct task_struct *p)
918 return unlikely(p->state == TASK_WAKING);
922 * __task_rq_lock - lock the runqueue a given task resides on.
923 * Must be called interrupts disabled.
925 static inline struct rq *__task_rq_lock(struct task_struct *p)
932 raw_spin_lock(&rq->lock);
933 if (likely(rq == task_rq(p)))
935 raw_spin_unlock(&rq->lock);
940 * task_rq_lock - lock the runqueue a given task resides on and disable
941 * interrupts. Note the ordering: we can safely lookup the task_rq without
942 * explicitly disabling preemption.
944 static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags)
950 local_irq_save(*flags);
952 raw_spin_lock(&rq->lock);
953 if (likely(rq == task_rq(p)))
955 raw_spin_unlock_irqrestore(&rq->lock, *flags);
959 static void __task_rq_unlock(struct rq *rq)
962 raw_spin_unlock(&rq->lock);
965 static inline void task_rq_unlock(struct rq *rq, unsigned long *flags)
968 raw_spin_unlock_irqrestore(&rq->lock, *flags);
972 * this_rq_lock - lock this runqueue and disable interrupts.
974 static struct rq *this_rq_lock(void)
981 raw_spin_lock(&rq->lock);
986 #ifdef CONFIG_SCHED_HRTICK
988 * Use HR-timers to deliver accurate preemption points.
990 * Its all a bit involved since we cannot program an hrt while holding the
991 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
994 * When we get rescheduled we reprogram the hrtick_timer outside of the
1000 * - enabled by features
1001 * - hrtimer is actually high res
1003 static inline int hrtick_enabled(struct rq *rq)
1005 if (!sched_feat(HRTICK))
1007 if (!cpu_active(cpu_of(rq)))
1009 return hrtimer_is_hres_active(&rq->hrtick_timer);
1012 static void hrtick_clear(struct rq *rq)
1014 if (hrtimer_active(&rq->hrtick_timer))
1015 hrtimer_cancel(&rq->hrtick_timer);
1019 * High-resolution timer tick.
1020 * Runs from hardirq context with interrupts disabled.
1022 static enum hrtimer_restart hrtick(struct hrtimer *timer)
1024 struct rq *rq = container_of(timer, struct rq, hrtick_timer);
1026 WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
1028 raw_spin_lock(&rq->lock);
1029 update_rq_clock(rq);
1030 rq->curr->sched_class->task_tick(rq, rq->curr, 1);
1031 raw_spin_unlock(&rq->lock);
1033 return HRTIMER_NORESTART;
1038 * called from hardirq (IPI) context
1040 static void __hrtick_start(void *arg)
1042 struct rq *rq = arg;
1044 raw_spin_lock(&rq->lock);
1045 hrtimer_restart(&rq->hrtick_timer);
1046 rq->hrtick_csd_pending = 0;
1047 raw_spin_unlock(&rq->lock);
1051 * Called to set the hrtick timer state.
1053 * called with rq->lock held and irqs disabled
1055 static void hrtick_start(struct rq *rq, u64 delay)
1057 struct hrtimer *timer = &rq->hrtick_timer;
1058 ktime_t time = ktime_add_ns(timer->base->get_time(), delay);
1060 hrtimer_set_expires(timer, time);
1062 if (rq == this_rq()) {
1063 hrtimer_restart(timer);
1064 } else if (!rq->hrtick_csd_pending) {
1065 __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd, 0);
1066 rq->hrtick_csd_pending = 1;
1071 hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu)
1073 int cpu = (int)(long)hcpu;
1076 case CPU_UP_CANCELED:
1077 case CPU_UP_CANCELED_FROZEN:
1078 case CPU_DOWN_PREPARE:
1079 case CPU_DOWN_PREPARE_FROZEN:
1081 case CPU_DEAD_FROZEN:
1082 hrtick_clear(cpu_rq(cpu));
1089 static __init void init_hrtick(void)
1091 hotcpu_notifier(hotplug_hrtick, 0);
1095 * Called to set the hrtick timer state.
1097 * called with rq->lock held and irqs disabled
1099 static void hrtick_start(struct rq *rq, u64 delay)
1101 __hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0,
1102 HRTIMER_MODE_REL_PINNED, 0);
1105 static inline void init_hrtick(void)
1108 #endif /* CONFIG_SMP */
1110 static void init_rq_hrtick(struct rq *rq)
1113 rq->hrtick_csd_pending = 0;
1115 rq->hrtick_csd.flags = 0;
1116 rq->hrtick_csd.func = __hrtick_start;
1117 rq->hrtick_csd.info = rq;
1120 hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1121 rq->hrtick_timer.function = hrtick;
1123 #else /* CONFIG_SCHED_HRTICK */
1124 static inline void hrtick_clear(struct rq *rq)
1128 static inline void init_rq_hrtick(struct rq *rq)
1132 static inline void init_hrtick(void)
1135 #endif /* CONFIG_SCHED_HRTICK */
1138 * resched_task - mark a task 'to be rescheduled now'.
1140 * On UP this means the setting of the need_resched flag, on SMP it
1141 * might also involve a cross-CPU call to trigger the scheduler on
1146 #ifndef tsk_is_polling
1147 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1150 static void resched_task(struct task_struct *p)
1154 assert_raw_spin_locked(&task_rq(p)->lock);
1156 if (test_tsk_need_resched(p))
1159 set_tsk_need_resched(p);
1162 if (cpu == smp_processor_id())
1165 /* NEED_RESCHED must be visible before we test polling */
1167 if (!tsk_is_polling(p))
1168 smp_send_reschedule(cpu);
1171 static void resched_cpu(int cpu)
1173 struct rq *rq = cpu_rq(cpu);
1174 unsigned long flags;
1176 if (!raw_spin_trylock_irqsave(&rq->lock, flags))
1178 resched_task(cpu_curr(cpu));
1179 raw_spin_unlock_irqrestore(&rq->lock, flags);
1184 * In the semi idle case, use the nearest busy cpu for migrating timers
1185 * from an idle cpu. This is good for power-savings.
1187 * We don't do similar optimization for completely idle system, as
1188 * selecting an idle cpu will add more delays to the timers than intended
1189 * (as that cpu's timer base may not be uptodate wrt jiffies etc).
1191 int get_nohz_timer_target(void)
1193 int cpu = smp_processor_id();
1195 struct sched_domain *sd;
1197 for_each_domain(cpu, sd) {
1198 for_each_cpu(i, sched_domain_span(sd))
1205 * When add_timer_on() enqueues a timer into the timer wheel of an
1206 * idle CPU then this timer might expire before the next timer event
1207 * which is scheduled to wake up that CPU. In case of a completely
1208 * idle system the next event might even be infinite time into the
1209 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1210 * leaves the inner idle loop so the newly added timer is taken into
1211 * account when the CPU goes back to idle and evaluates the timer
1212 * wheel for the next timer event.
1214 void wake_up_idle_cpu(int cpu)
1216 struct rq *rq = cpu_rq(cpu);
1218 if (cpu == smp_processor_id())
1222 * This is safe, as this function is called with the timer
1223 * wheel base lock of (cpu) held. When the CPU is on the way
1224 * to idle and has not yet set rq->curr to idle then it will
1225 * be serialized on the timer wheel base lock and take the new
1226 * timer into account automatically.
1228 if (rq->curr != rq->idle)
1232 * We can set TIF_RESCHED on the idle task of the other CPU
1233 * lockless. The worst case is that the other CPU runs the
1234 * idle task through an additional NOOP schedule()
1236 set_tsk_need_resched(rq->idle);
1238 /* NEED_RESCHED must be visible before we test polling */
1240 if (!tsk_is_polling(rq->idle))
1241 smp_send_reschedule(cpu);
1244 #endif /* CONFIG_NO_HZ */
1246 static u64 sched_avg_period(void)
1248 return (u64)sysctl_sched_time_avg * NSEC_PER_MSEC / 2;
1251 static void sched_avg_update(struct rq *rq)
1253 s64 period = sched_avg_period();
1255 while ((s64)(rq->clock - rq->age_stamp) > period) {
1257 * Inline assembly required to prevent the compiler
1258 * optimising this loop into a divmod call.
1259 * See __iter_div_u64_rem() for another example of this.
1261 asm("" : "+rm" (rq->age_stamp));
1262 rq->age_stamp += period;
1267 static void sched_rt_avg_update(struct rq *rq, u64 rt_delta)
1269 rq->rt_avg += rt_delta;
1270 sched_avg_update(rq);
1273 #else /* !CONFIG_SMP */
1274 static void resched_task(struct task_struct *p)
1276 assert_raw_spin_locked(&task_rq(p)->lock);
1277 set_tsk_need_resched(p);
1280 static void sched_rt_avg_update(struct rq *rq, u64 rt_delta)
1284 static void sched_avg_update(struct rq *rq)
1287 #endif /* CONFIG_SMP */
1289 #if BITS_PER_LONG == 32
1290 # define WMULT_CONST (~0UL)
1292 # define WMULT_CONST (1UL << 32)
1295 #define WMULT_SHIFT 32
1298 * Shift right and round:
1300 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1303 * delta *= weight / lw
1305 static unsigned long
1306 calc_delta_mine(unsigned long delta_exec, unsigned long weight,
1307 struct load_weight *lw)
1311 if (!lw->inv_weight) {
1312 if (BITS_PER_LONG > 32 && unlikely(lw->weight >= WMULT_CONST))
1315 lw->inv_weight = 1 + (WMULT_CONST-lw->weight/2)
1319 tmp = (u64)delta_exec * weight;
1321 * Check whether we'd overflow the 64-bit multiplication:
1323 if (unlikely(tmp > WMULT_CONST))
1324 tmp = SRR(SRR(tmp, WMULT_SHIFT/2) * lw->inv_weight,
1327 tmp = SRR(tmp * lw->inv_weight, WMULT_SHIFT);
1329 return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX);
1332 static inline void update_load_add(struct load_weight *lw, unsigned long inc)
1338 static inline void update_load_sub(struct load_weight *lw, unsigned long dec)
1344 static inline void update_load_set(struct load_weight *lw, unsigned long w)
1351 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1352 * of tasks with abnormal "nice" values across CPUs the contribution that
1353 * each task makes to its run queue's load is weighted according to its
1354 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1355 * scaled version of the new time slice allocation that they receive on time
1359 #define WEIGHT_IDLEPRIO 3
1360 #define WMULT_IDLEPRIO 1431655765
1363 * Nice levels are multiplicative, with a gentle 10% change for every
1364 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1365 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1366 * that remained on nice 0.
1368 * The "10% effect" is relative and cumulative: from _any_ nice level,
1369 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1370 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1371 * If a task goes up by ~10% and another task goes down by ~10% then
1372 * the relative distance between them is ~25%.)
1374 static const int prio_to_weight[40] = {
1375 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1376 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1377 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1378 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1379 /* 0 */ 1024, 820, 655, 526, 423,
1380 /* 5 */ 335, 272, 215, 172, 137,
1381 /* 10 */ 110, 87, 70, 56, 45,
1382 /* 15 */ 36, 29, 23, 18, 15,
1386 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1388 * In cases where the weight does not change often, we can use the
1389 * precalculated inverse to speed up arithmetics by turning divisions
1390 * into multiplications:
1392 static const u32 prio_to_wmult[40] = {
1393 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1394 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1395 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1396 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1397 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1398 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1399 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1400 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1403 /* Time spent by the tasks of the cpu accounting group executing in ... */
1404 enum cpuacct_stat_index {
1405 CPUACCT_STAT_USER, /* ... user mode */
1406 CPUACCT_STAT_SYSTEM, /* ... kernel mode */
1408 CPUACCT_STAT_NSTATS,
1411 #ifdef CONFIG_CGROUP_CPUACCT
1412 static void cpuacct_charge(struct task_struct *tsk, u64 cputime);
1413 static void cpuacct_update_stats(struct task_struct *tsk,
1414 enum cpuacct_stat_index idx, cputime_t val);
1416 static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}
1417 static inline void cpuacct_update_stats(struct task_struct *tsk,
1418 enum cpuacct_stat_index idx, cputime_t val) {}
1421 static inline void inc_cpu_load(struct rq *rq, unsigned long load)
1423 update_load_add(&rq->load, load);
1426 static inline void dec_cpu_load(struct rq *rq, unsigned long load)
1428 update_load_sub(&rq->load, load);
1431 #if (defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)) || defined(CONFIG_RT_GROUP_SCHED)
1432 typedef int (*tg_visitor)(struct task_group *, void *);
1435 * Iterate the full tree, calling @down when first entering a node and @up when
1436 * leaving it for the final time.
1438 static int walk_tg_tree(tg_visitor down, tg_visitor up, void *data)
1440 struct task_group *parent, *child;
1444 parent = &root_task_group;
1446 ret = (*down)(parent, data);
1449 list_for_each_entry_rcu(child, &parent->children, siblings) {
1456 ret = (*up)(parent, data);
1461 parent = parent->parent;
1470 static int tg_nop(struct task_group *tg, void *data)
1477 /* Used instead of source_load when we know the type == 0 */
1478 static unsigned long weighted_cpuload(const int cpu)
1480 return cpu_rq(cpu)->load.weight;
1484 * Return a low guess at the load of a migration-source cpu weighted
1485 * according to the scheduling class and "nice" value.
1487 * We want to under-estimate the load of migration sources, to
1488 * balance conservatively.
1490 static unsigned long source_load(int cpu, int type)
1492 struct rq *rq = cpu_rq(cpu);
1493 unsigned long total = weighted_cpuload(cpu);
1495 if (type == 0 || !sched_feat(LB_BIAS))
1498 return min(rq->cpu_load[type-1], total);
1502 * Return a high guess at the load of a migration-target cpu weighted
1503 * according to the scheduling class and "nice" value.
1505 static unsigned long target_load(int cpu, int type)
1507 struct rq *rq = cpu_rq(cpu);
1508 unsigned long total = weighted_cpuload(cpu);
1510 if (type == 0 || !sched_feat(LB_BIAS))
1513 return max(rq->cpu_load[type-1], total);
1516 static unsigned long power_of(int cpu)
1518 return cpu_rq(cpu)->cpu_power;
1521 static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd);
1523 static unsigned long cpu_avg_load_per_task(int cpu)
1525 struct rq *rq = cpu_rq(cpu);
1526 unsigned long nr_running = ACCESS_ONCE(rq->nr_running);
1529 rq->avg_load_per_task = rq->load.weight / nr_running;
1531 rq->avg_load_per_task = 0;
1533 return rq->avg_load_per_task;
1536 #ifdef CONFIG_FAIR_GROUP_SCHED
1539 * Compute the cpu's hierarchical load factor for each task group.
1540 * This needs to be done in a top-down fashion because the load of a child
1541 * group is a fraction of its parents load.
1543 static int tg_load_down(struct task_group *tg, void *data)
1546 long cpu = (long)data;
1549 load = cpu_rq(cpu)->load.weight;
1551 load = tg->parent->cfs_rq[cpu]->h_load;
1552 load *= tg->se[cpu]->load.weight;
1553 load /= tg->parent->cfs_rq[cpu]->load.weight + 1;
1556 tg->cfs_rq[cpu]->h_load = load;
1561 static void update_h_load(long cpu)
1563 walk_tg_tree(tg_load_down, tg_nop, (void *)cpu);
1568 #ifdef CONFIG_PREEMPT
1570 static void double_rq_lock(struct rq *rq1, struct rq *rq2);
1573 * fair double_lock_balance: Safely acquires both rq->locks in a fair
1574 * way at the expense of forcing extra atomic operations in all
1575 * invocations. This assures that the double_lock is acquired using the
1576 * same underlying policy as the spinlock_t on this architecture, which
1577 * reduces latency compared to the unfair variant below. However, it
1578 * also adds more overhead and therefore may reduce throughput.
1580 static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
1581 __releases(this_rq->lock)
1582 __acquires(busiest->lock)
1583 __acquires(this_rq->lock)
1585 raw_spin_unlock(&this_rq->lock);
1586 double_rq_lock(this_rq, busiest);
1593 * Unfair double_lock_balance: Optimizes throughput at the expense of
1594 * latency by eliminating extra atomic operations when the locks are
1595 * already in proper order on entry. This favors lower cpu-ids and will
1596 * grant the double lock to lower cpus over higher ids under contention,
1597 * regardless of entry order into the function.
1599 static int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
1600 __releases(this_rq->lock)
1601 __acquires(busiest->lock)
1602 __acquires(this_rq->lock)
1606 if (unlikely(!raw_spin_trylock(&busiest->lock))) {
1607 if (busiest < this_rq) {
1608 raw_spin_unlock(&this_rq->lock);
1609 raw_spin_lock(&busiest->lock);
1610 raw_spin_lock_nested(&this_rq->lock,
1611 SINGLE_DEPTH_NESTING);
1614 raw_spin_lock_nested(&busiest->lock,
1615 SINGLE_DEPTH_NESTING);
1620 #endif /* CONFIG_PREEMPT */
1623 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
1625 static int double_lock_balance(struct rq *this_rq, struct rq *busiest)
1627 if (unlikely(!irqs_disabled())) {
1628 /* printk() doesn't work good under rq->lock */
1629 raw_spin_unlock(&this_rq->lock);
1633 return _double_lock_balance(this_rq, busiest);
1636 static inline void double_unlock_balance(struct rq *this_rq, struct rq *busiest)
1637 __releases(busiest->lock)
1639 raw_spin_unlock(&busiest->lock);
1640 lock_set_subclass(&this_rq->lock.dep_map, 0, _RET_IP_);
1644 * double_rq_lock - safely lock two runqueues
1646 * Note this does not disable interrupts like task_rq_lock,
1647 * you need to do so manually before calling.
1649 static void double_rq_lock(struct rq *rq1, struct rq *rq2)
1650 __acquires(rq1->lock)
1651 __acquires(rq2->lock)
1653 BUG_ON(!irqs_disabled());
1655 raw_spin_lock(&rq1->lock);
1656 __acquire(rq2->lock); /* Fake it out ;) */
1659 raw_spin_lock(&rq1->lock);
1660 raw_spin_lock_nested(&rq2->lock, SINGLE_DEPTH_NESTING);
1662 raw_spin_lock(&rq2->lock);
1663 raw_spin_lock_nested(&rq1->lock, SINGLE_DEPTH_NESTING);
1669 * double_rq_unlock - safely unlock two runqueues
1671 * Note this does not restore interrupts like task_rq_unlock,
1672 * you need to do so manually after calling.
1674 static void double_rq_unlock(struct rq *rq1, struct rq *rq2)
1675 __releases(rq1->lock)
1676 __releases(rq2->lock)
1678 raw_spin_unlock(&rq1->lock);
1680 raw_spin_unlock(&rq2->lock);
1682 __release(rq2->lock);
1685 #else /* CONFIG_SMP */
1688 * double_rq_lock - safely lock two runqueues
1690 * Note this does not disable interrupts like task_rq_lock,
1691 * you need to do so manually before calling.
1693 static void double_rq_lock(struct rq *rq1, struct rq *rq2)
1694 __acquires(rq1->lock)
1695 __acquires(rq2->lock)
1697 BUG_ON(!irqs_disabled());
1699 raw_spin_lock(&rq1->lock);
1700 __acquire(rq2->lock); /* Fake it out ;) */
1704 * double_rq_unlock - safely unlock two runqueues
1706 * Note this does not restore interrupts like task_rq_unlock,
1707 * you need to do so manually after calling.
1709 static void double_rq_unlock(struct rq *rq1, struct rq *rq2)
1710 __releases(rq1->lock)
1711 __releases(rq2->lock)
1714 raw_spin_unlock(&rq1->lock);
1715 __release(rq2->lock);
1720 static void calc_load_account_idle(struct rq *this_rq);
1721 static void update_sysctl(void);
1722 static int get_update_sysctl_factor(void);
1723 static void update_cpu_load(struct rq *this_rq);
1725 static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
1727 set_task_rq(p, cpu);
1730 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1731 * successfuly executed on another CPU. We must ensure that updates of
1732 * per-task data have been completed by this moment.
1735 task_thread_info(p)->cpu = cpu;
1739 static const struct sched_class rt_sched_class;
1741 #define sched_class_highest (&stop_sched_class)
1742 #define for_each_class(class) \
1743 for (class = sched_class_highest; class; class = class->next)
1745 #include "sched_stats.h"
1747 static void inc_nr_running(struct rq *rq)
1752 static void dec_nr_running(struct rq *rq)
1757 static void set_load_weight(struct task_struct *p)
1760 * SCHED_IDLE tasks get minimal weight:
1762 if (p->policy == SCHED_IDLE) {
1763 p->se.load.weight = WEIGHT_IDLEPRIO;
1764 p->se.load.inv_weight = WMULT_IDLEPRIO;
1768 p->se.load.weight = prio_to_weight[p->static_prio - MAX_RT_PRIO];
1769 p->se.load.inv_weight = prio_to_wmult[p->static_prio - MAX_RT_PRIO];
1772 static void enqueue_task(struct rq *rq, struct task_struct *p, int flags)
1774 update_rq_clock(rq);
1775 sched_info_queued(p);
1776 p->sched_class->enqueue_task(rq, p, flags);
1780 static void dequeue_task(struct rq *rq, struct task_struct *p, int flags)
1782 update_rq_clock(rq);
1783 sched_info_dequeued(p);
1784 p->sched_class->dequeue_task(rq, p, flags);
1789 * activate_task - move a task to the runqueue.
1791 static void activate_task(struct rq *rq, struct task_struct *p, int flags)
1793 if (task_contributes_to_load(p))
1794 rq->nr_uninterruptible--;
1796 enqueue_task(rq, p, flags);
1801 * deactivate_task - remove a task from the runqueue.
1803 static void deactivate_task(struct rq *rq, struct task_struct *p, int flags)
1805 if (task_contributes_to_load(p))
1806 rq->nr_uninterruptible++;
1808 dequeue_task(rq, p, flags);
1812 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
1815 * There are no locks covering percpu hardirq/softirq time.
1816 * They are only modified in account_system_vtime, on corresponding CPU
1817 * with interrupts disabled. So, writes are safe.
1818 * They are read and saved off onto struct rq in update_rq_clock().
1819 * This may result in other CPU reading this CPU's irq time and can
1820 * race with irq/account_system_vtime on this CPU. We would either get old
1821 * or new value with a side effect of accounting a slice of irq time to wrong
1822 * task when irq is in progress while we read rq->clock. That is a worthy
1823 * compromise in place of having locks on each irq in account_system_time.
1825 static DEFINE_PER_CPU(u64, cpu_hardirq_time);
1826 static DEFINE_PER_CPU(u64, cpu_softirq_time);
1828 static DEFINE_PER_CPU(u64, irq_start_time);
1829 static int sched_clock_irqtime;
1831 void enable_sched_clock_irqtime(void)
1833 sched_clock_irqtime = 1;
1836 void disable_sched_clock_irqtime(void)
1838 sched_clock_irqtime = 0;
1841 #ifndef CONFIG_64BIT
1842 static DEFINE_PER_CPU(seqcount_t, irq_time_seq);
1844 static inline void irq_time_write_begin(void)
1846 __this_cpu_inc(irq_time_seq.sequence);
1850 static inline void irq_time_write_end(void)
1853 __this_cpu_inc(irq_time_seq.sequence);
1856 static inline u64 irq_time_read(int cpu)
1862 seq = read_seqcount_begin(&per_cpu(irq_time_seq, cpu));
1863 irq_time = per_cpu(cpu_softirq_time, cpu) +
1864 per_cpu(cpu_hardirq_time, cpu);
1865 } while (read_seqcount_retry(&per_cpu(irq_time_seq, cpu), seq));
1869 #else /* CONFIG_64BIT */
1870 static inline void irq_time_write_begin(void)
1874 static inline void irq_time_write_end(void)
1878 static inline u64 irq_time_read(int cpu)
1880 return per_cpu(cpu_softirq_time, cpu) + per_cpu(cpu_hardirq_time, cpu);
1882 #endif /* CONFIG_64BIT */
1885 * Called before incrementing preempt_count on {soft,}irq_enter
1886 * and before decrementing preempt_count on {soft,}irq_exit.
1888 void account_system_vtime(struct task_struct *curr)
1890 unsigned long flags;
1894 if (!sched_clock_irqtime)
1897 local_irq_save(flags);
1899 cpu = smp_processor_id();
1900 delta = sched_clock_cpu(cpu) - __this_cpu_read(irq_start_time);
1901 __this_cpu_add(irq_start_time, delta);
1903 irq_time_write_begin();
1905 * We do not account for softirq time from ksoftirqd here.
1906 * We want to continue accounting softirq time to ksoftirqd thread
1907 * in that case, so as not to confuse scheduler with a special task
1908 * that do not consume any time, but still wants to run.
1910 if (hardirq_count())
1911 __this_cpu_add(cpu_hardirq_time, delta);
1912 else if (in_serving_softirq() && curr != this_cpu_ksoftirqd())
1913 __this_cpu_add(cpu_softirq_time, delta);
1915 irq_time_write_end();
1916 local_irq_restore(flags);
1918 EXPORT_SYMBOL_GPL(account_system_vtime);
1920 static void update_rq_clock_task(struct rq *rq, s64 delta)
1924 irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time;
1927 * Since irq_time is only updated on {soft,}irq_exit, we might run into
1928 * this case when a previous update_rq_clock() happened inside a
1929 * {soft,}irq region.
1931 * When this happens, we stop ->clock_task and only update the
1932 * prev_irq_time stamp to account for the part that fit, so that a next
1933 * update will consume the rest. This ensures ->clock_task is
1936 * It does however cause some slight miss-attribution of {soft,}irq
1937 * time, a more accurate solution would be to update the irq_time using
1938 * the current rq->clock timestamp, except that would require using
1941 if (irq_delta > delta)
1944 rq->prev_irq_time += irq_delta;
1946 rq->clock_task += delta;
1948 if (irq_delta && sched_feat(NONIRQ_POWER))
1949 sched_rt_avg_update(rq, irq_delta);
1952 static int irqtime_account_hi_update(void)
1954 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
1955 unsigned long flags;
1959 local_irq_save(flags);
1960 latest_ns = this_cpu_read(cpu_hardirq_time);
1961 if (cputime64_gt(nsecs_to_cputime64(latest_ns), cpustat->irq))
1963 local_irq_restore(flags);
1967 static int irqtime_account_si_update(void)
1969 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
1970 unsigned long flags;
1974 local_irq_save(flags);
1975 latest_ns = this_cpu_read(cpu_softirq_time);
1976 if (cputime64_gt(nsecs_to_cputime64(latest_ns), cpustat->softirq))
1978 local_irq_restore(flags);
1982 #else /* CONFIG_IRQ_TIME_ACCOUNTING */
1984 #define sched_clock_irqtime (0)
1986 static void update_rq_clock_task(struct rq *rq, s64 delta)
1988 rq->clock_task += delta;
1991 #endif /* CONFIG_IRQ_TIME_ACCOUNTING */
1993 #include "sched_idletask.c"
1994 #include "sched_fair.c"
1995 #include "sched_rt.c"
1996 #include "sched_autogroup.c"
1997 #include "sched_stoptask.c"
1998 #ifdef CONFIG_SCHED_DEBUG
1999 # include "sched_debug.c"
2002 void sched_set_stop_task(int cpu, struct task_struct *stop)
2004 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
2005 struct task_struct *old_stop = cpu_rq(cpu)->stop;
2009 * Make it appear like a SCHED_FIFO task, its something
2010 * userspace knows about and won't get confused about.
2012 * Also, it will make PI more or less work without too
2013 * much confusion -- but then, stop work should not
2014 * rely on PI working anyway.
2016 sched_setscheduler_nocheck(stop, SCHED_FIFO, ¶m);
2018 stop->sched_class = &stop_sched_class;
2021 cpu_rq(cpu)->stop = stop;
2025 * Reset it back to a normal scheduling class so that
2026 * it can die in pieces.
2028 old_stop->sched_class = &rt_sched_class;
2033 * __normal_prio - return the priority that is based on the static prio
2035 static inline int __normal_prio(struct task_struct *p)
2037 return p->static_prio;
2041 * Calculate the expected normal priority: i.e. priority
2042 * without taking RT-inheritance into account. Might be
2043 * boosted by interactivity modifiers. Changes upon fork,
2044 * setprio syscalls, and whenever the interactivity
2045 * estimator recalculates.
2047 static inline int normal_prio(struct task_struct *p)
2051 if (task_has_rt_policy(p))
2052 prio = MAX_RT_PRIO-1 - p->rt_priority;
2054 prio = __normal_prio(p);
2059 * Calculate the current priority, i.e. the priority
2060 * taken into account by the scheduler. This value might
2061 * be boosted by RT tasks, or might be boosted by
2062 * interactivity modifiers. Will be RT if the task got
2063 * RT-boosted. If not then it returns p->normal_prio.
2065 static int effective_prio(struct task_struct *p)
2067 p->normal_prio = normal_prio(p);
2069 * If we are RT tasks or we were boosted to RT priority,
2070 * keep the priority unchanged. Otherwise, update priority
2071 * to the normal priority:
2073 if (!rt_prio(p->prio))
2074 return p->normal_prio;
2079 * task_curr - is this task currently executing on a CPU?
2080 * @p: the task in question.
2082 inline int task_curr(const struct task_struct *p)
2084 return cpu_curr(task_cpu(p)) == p;
2087 static inline void check_class_changed(struct rq *rq, struct task_struct *p,
2088 const struct sched_class *prev_class,
2091 if (prev_class != p->sched_class) {
2092 if (prev_class->switched_from)
2093 prev_class->switched_from(rq, p);
2094 p->sched_class->switched_to(rq, p);
2095 } else if (oldprio != p->prio)
2096 p->sched_class->prio_changed(rq, p, oldprio);
2099 static void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags)
2101 const struct sched_class *class;
2103 if (p->sched_class == rq->curr->sched_class) {
2104 rq->curr->sched_class->check_preempt_curr(rq, p, flags);
2106 for_each_class(class) {
2107 if (class == rq->curr->sched_class)
2109 if (class == p->sched_class) {
2110 resched_task(rq->curr);
2117 * A queue event has occurred, and we're going to schedule. In
2118 * this case, we can save a useless back to back clock update.
2120 if (rq->curr->se.on_rq && test_tsk_need_resched(rq->curr))
2121 rq->skip_clock_update = 1;
2126 * Is this task likely cache-hot:
2129 task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
2133 if (p->sched_class != &fair_sched_class)
2136 if (unlikely(p->policy == SCHED_IDLE))
2140 * Buddy candidates are cache hot:
2142 if (sched_feat(CACHE_HOT_BUDDY) && this_rq()->nr_running &&
2143 (&p->se == cfs_rq_of(&p->se)->next ||
2144 &p->se == cfs_rq_of(&p->se)->last))
2147 if (sysctl_sched_migration_cost == -1)
2149 if (sysctl_sched_migration_cost == 0)
2152 delta = now - p->se.exec_start;
2154 return delta < (s64)sysctl_sched_migration_cost;
2157 void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
2159 #ifdef CONFIG_SCHED_DEBUG
2161 * We should never call set_task_cpu() on a blocked task,
2162 * ttwu() will sort out the placement.
2164 WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING &&
2165 !(task_thread_info(p)->preempt_count & PREEMPT_ACTIVE));
2168 trace_sched_migrate_task(p, new_cpu);
2170 if (task_cpu(p) != new_cpu) {
2171 p->se.nr_migrations++;
2172 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, 1, 1, NULL, 0);
2175 __set_task_cpu(p, new_cpu);
2178 struct migration_arg {
2179 struct task_struct *task;
2183 static int migration_cpu_stop(void *data);
2186 * The task's runqueue lock must be held.
2187 * Returns true if you have to wait for migration thread.
2189 static bool migrate_task(struct task_struct *p, struct rq *rq)
2192 * If the task is not on a runqueue (and not running), then
2193 * the next wake-up will properly place the task.
2195 return p->se.on_rq || task_running(rq, p);
2199 * wait_task_inactive - wait for a thread to unschedule.
2201 * If @match_state is nonzero, it's the @p->state value just checked and
2202 * not expected to change. If it changes, i.e. @p might have woken up,
2203 * then return zero. When we succeed in waiting for @p to be off its CPU,
2204 * we return a positive number (its total switch count). If a second call
2205 * a short while later returns the same number, the caller can be sure that
2206 * @p has remained unscheduled the whole time.
2208 * The caller must ensure that the task *will* unschedule sometime soon,
2209 * else this function might spin for a *long* time. This function can't
2210 * be called with interrupts off, or it may introduce deadlock with
2211 * smp_call_function() if an IPI is sent by the same process we are
2212 * waiting to become inactive.
2214 unsigned long wait_task_inactive(struct task_struct *p, long match_state)
2216 unsigned long flags;
2223 * We do the initial early heuristics without holding
2224 * any task-queue locks at all. We'll only try to get
2225 * the runqueue lock when things look like they will
2231 * If the task is actively running on another CPU
2232 * still, just relax and busy-wait without holding
2235 * NOTE! Since we don't hold any locks, it's not
2236 * even sure that "rq" stays as the right runqueue!
2237 * But we don't care, since "task_running()" will
2238 * return false if the runqueue has changed and p
2239 * is actually now running somewhere else!
2241 while (task_running(rq, p)) {
2242 if (match_state && unlikely(p->state != match_state))
2248 * Ok, time to look more closely! We need the rq
2249 * lock now, to be *sure*. If we're wrong, we'll
2250 * just go back and repeat.
2252 rq = task_rq_lock(p, &flags);
2253 trace_sched_wait_task(p);
2254 running = task_running(rq, p);
2255 on_rq = p->se.on_rq;
2257 if (!match_state || p->state == match_state)
2258 ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
2259 task_rq_unlock(rq, &flags);
2262 * If it changed from the expected state, bail out now.
2264 if (unlikely(!ncsw))
2268 * Was it really running after all now that we
2269 * checked with the proper locks actually held?
2271 * Oops. Go back and try again..
2273 if (unlikely(running)) {
2279 * It's not enough that it's not actively running,
2280 * it must be off the runqueue _entirely_, and not
2283 * So if it was still runnable (but just not actively
2284 * running right now), it's preempted, and we should
2285 * yield - it could be a while.
2287 if (unlikely(on_rq)) {
2288 ktime_t to = ktime_set(0, NSEC_PER_SEC/HZ);
2290 set_current_state(TASK_UNINTERRUPTIBLE);
2291 schedule_hrtimeout(&to, HRTIMER_MODE_REL);
2296 * Ahh, all good. It wasn't running, and it wasn't
2297 * runnable, which means that it will never become
2298 * running in the future either. We're all done!
2307 * kick_process - kick a running thread to enter/exit the kernel
2308 * @p: the to-be-kicked thread
2310 * Cause a process which is running on another CPU to enter
2311 * kernel-mode, without any delay. (to get signals handled.)
2313 * NOTE: this function doesn't have to take the runqueue lock,
2314 * because all it wants to ensure is that the remote task enters
2315 * the kernel. If the IPI races and the task has been migrated
2316 * to another CPU then no harm is done and the purpose has been
2319 void kick_process(struct task_struct *p)
2325 if ((cpu != smp_processor_id()) && task_curr(p))
2326 smp_send_reschedule(cpu);
2329 EXPORT_SYMBOL_GPL(kick_process);
2330 #endif /* CONFIG_SMP */
2334 * ->cpus_allowed is protected by either TASK_WAKING or rq->lock held.
2336 static int select_fallback_rq(int cpu, struct task_struct *p)
2339 const struct cpumask *nodemask = cpumask_of_node(cpu_to_node(cpu));
2341 /* Look for allowed, online CPU in same node. */
2342 for_each_cpu_and(dest_cpu, nodemask, cpu_active_mask)
2343 if (cpumask_test_cpu(dest_cpu, &p->cpus_allowed))
2346 /* Any allowed, online CPU? */
2347 dest_cpu = cpumask_any_and(&p->cpus_allowed, cpu_active_mask);
2348 if (dest_cpu < nr_cpu_ids)
2351 /* No more Mr. Nice Guy. */
2352 dest_cpu = cpuset_cpus_allowed_fallback(p);
2354 * Don't tell them about moving exiting tasks or
2355 * kernel threads (both mm NULL), since they never
2358 if (p->mm && printk_ratelimit()) {
2359 printk(KERN_INFO "process %d (%s) no longer affine to cpu%d\n",
2360 task_pid_nr(p), p->comm, cpu);
2367 * The caller (fork, wakeup) owns TASK_WAKING, ->cpus_allowed is stable.
2370 int select_task_rq(struct rq *rq, struct task_struct *p, int sd_flags, int wake_flags)
2372 int cpu = p->sched_class->select_task_rq(rq, p, sd_flags, wake_flags);
2375 * In order not to call set_task_cpu() on a blocking task we need
2376 * to rely on ttwu() to place the task on a valid ->cpus_allowed
2379 * Since this is common to all placement strategies, this lives here.
2381 * [ this allows ->select_task() to simply return task_cpu(p) and
2382 * not worry about this generic constraint ]
2384 if (unlikely(!cpumask_test_cpu(cpu, &p->cpus_allowed) ||
2386 cpu = select_fallback_rq(task_cpu(p), p);
2391 static void update_avg(u64 *avg, u64 sample)
2393 s64 diff = sample - *avg;
2398 static inline void ttwu_activate(struct task_struct *p, struct rq *rq,
2399 bool is_sync, bool is_migrate, bool is_local,
2400 unsigned long en_flags)
2402 schedstat_inc(p, se.statistics.nr_wakeups);
2404 schedstat_inc(p, se.statistics.nr_wakeups_sync);
2406 schedstat_inc(p, se.statistics.nr_wakeups_migrate);
2408 schedstat_inc(p, se.statistics.nr_wakeups_local);
2410 schedstat_inc(p, se.statistics.nr_wakeups_remote);
2412 activate_task(rq, p, en_flags);
2415 static inline void ttwu_post_activation(struct task_struct *p, struct rq *rq,
2416 int wake_flags, bool success)
2418 trace_sched_wakeup(p, success);
2419 check_preempt_curr(rq, p, wake_flags);
2421 p->state = TASK_RUNNING;
2423 if (p->sched_class->task_woken)
2424 p->sched_class->task_woken(rq, p);
2426 if (unlikely(rq->idle_stamp)) {
2427 u64 delta = rq->clock - rq->idle_stamp;
2428 u64 max = 2*sysctl_sched_migration_cost;
2433 update_avg(&rq->avg_idle, delta);
2437 /* if a worker is waking up, notify workqueue */
2438 if ((p->flags & PF_WQ_WORKER) && success)
2439 wq_worker_waking_up(p, cpu_of(rq));
2443 * try_to_wake_up - wake up a thread
2444 * @p: the thread to be awakened
2445 * @state: the mask of task states that can be woken
2446 * @wake_flags: wake modifier flags (WF_*)
2448 * Put it on the run-queue if it's not already there. The "current"
2449 * thread is always on the run-queue (except when the actual
2450 * re-schedule is in progress), and as such you're allowed to do
2451 * the simpler "current->state = TASK_RUNNING" to mark yourself
2452 * runnable without the overhead of this.
2454 * Returns %true if @p was woken up, %false if it was already running
2455 * or @state didn't match @p's state.
2457 static int try_to_wake_up(struct task_struct *p, unsigned int state,
2460 int cpu, orig_cpu, this_cpu, success = 0;
2461 unsigned long flags;
2462 unsigned long en_flags = ENQUEUE_WAKEUP;
2465 this_cpu = get_cpu();
2468 rq = task_rq_lock(p, &flags);
2469 if (!(p->state & state))
2479 if (unlikely(task_running(rq, p)))
2483 * In order to handle concurrent wakeups and release the rq->lock
2484 * we put the task in TASK_WAKING state.
2486 * First fix up the nr_uninterruptible count:
2488 if (task_contributes_to_load(p)) {
2489 if (likely(cpu_online(orig_cpu)))
2490 rq->nr_uninterruptible--;
2492 this_rq()->nr_uninterruptible--;
2494 p->state = TASK_WAKING;
2496 if (p->sched_class->task_waking) {
2497 p->sched_class->task_waking(rq, p);
2498 en_flags |= ENQUEUE_WAKING;
2501 cpu = select_task_rq(rq, p, SD_BALANCE_WAKE, wake_flags);
2502 if (cpu != orig_cpu)
2503 set_task_cpu(p, cpu);
2504 __task_rq_unlock(rq);
2507 raw_spin_lock(&rq->lock);
2510 * We migrated the task without holding either rq->lock, however
2511 * since the task is not on the task list itself, nobody else
2512 * will try and migrate the task, hence the rq should match the
2513 * cpu we just moved it to.
2515 WARN_ON(task_cpu(p) != cpu);
2516 WARN_ON(p->state != TASK_WAKING);
2518 #ifdef CONFIG_SCHEDSTATS
2519 schedstat_inc(rq, ttwu_count);
2520 if (cpu == this_cpu)
2521 schedstat_inc(rq, ttwu_local);
2523 struct sched_domain *sd;
2524 for_each_domain(this_cpu, sd) {
2525 if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
2526 schedstat_inc(sd, ttwu_wake_remote);
2531 #endif /* CONFIG_SCHEDSTATS */
2534 #endif /* CONFIG_SMP */
2535 ttwu_activate(p, rq, wake_flags & WF_SYNC, orig_cpu != cpu,
2536 cpu == this_cpu, en_flags);
2539 ttwu_post_activation(p, rq, wake_flags, success);
2541 task_rq_unlock(rq, &flags);
2548 * try_to_wake_up_local - try to wake up a local task with rq lock held
2549 * @p: the thread to be awakened
2551 * Put @p on the run-queue if it's not already there. The caller must
2552 * ensure that this_rq() is locked, @p is bound to this_rq() and not
2553 * the current task. this_rq() stays locked over invocation.
2555 static void try_to_wake_up_local(struct task_struct *p)
2557 struct rq *rq = task_rq(p);
2558 bool success = false;
2560 BUG_ON(rq != this_rq());
2561 BUG_ON(p == current);
2562 lockdep_assert_held(&rq->lock);
2564 if (!(p->state & TASK_NORMAL))
2568 if (likely(!task_running(rq, p))) {
2569 schedstat_inc(rq, ttwu_count);
2570 schedstat_inc(rq, ttwu_local);
2572 ttwu_activate(p, rq, false, false, true, ENQUEUE_WAKEUP);
2575 ttwu_post_activation(p, rq, 0, success);
2579 * wake_up_process - Wake up a specific process
2580 * @p: The process to be woken up.
2582 * Attempt to wake up the nominated process and move it to the set of runnable
2583 * processes. Returns 1 if the process was woken up, 0 if it was already
2586 * It may be assumed that this function implies a write memory barrier before
2587 * changing the task state if and only if any tasks are woken up.
2589 int wake_up_process(struct task_struct *p)
2591 return try_to_wake_up(p, TASK_ALL, 0);
2593 EXPORT_SYMBOL(wake_up_process);
2595 int wake_up_state(struct task_struct *p, unsigned int state)
2597 return try_to_wake_up(p, state, 0);
2601 * Perform scheduler related setup for a newly forked process p.
2602 * p is forked by current.
2604 * __sched_fork() is basic setup used by init_idle() too:
2606 static void __sched_fork(struct task_struct *p)
2608 p->se.exec_start = 0;
2609 p->se.sum_exec_runtime = 0;
2610 p->se.prev_sum_exec_runtime = 0;
2611 p->se.nr_migrations = 0;
2614 #ifdef CONFIG_SCHEDSTATS
2615 memset(&p->se.statistics, 0, sizeof(p->se.statistics));
2618 INIT_LIST_HEAD(&p->rt.run_list);
2620 INIT_LIST_HEAD(&p->se.group_node);
2622 #ifdef CONFIG_PREEMPT_NOTIFIERS
2623 INIT_HLIST_HEAD(&p->preempt_notifiers);
2628 * fork()/clone()-time setup:
2630 void sched_fork(struct task_struct *p, int clone_flags)
2632 int cpu = get_cpu();
2636 * We mark the process as running here. This guarantees that
2637 * nobody will actually run it, and a signal or other external
2638 * event cannot wake it up and insert it on the runqueue either.
2640 p->state = TASK_RUNNING;
2643 * Revert to default priority/policy on fork if requested.
2645 if (unlikely(p->sched_reset_on_fork)) {
2646 if (p->policy == SCHED_FIFO || p->policy == SCHED_RR) {
2647 p->policy = SCHED_NORMAL;
2648 p->normal_prio = p->static_prio;
2651 if (PRIO_TO_NICE(p->static_prio) < 0) {
2652 p->static_prio = NICE_TO_PRIO(0);
2653 p->normal_prio = p->static_prio;
2658 * We don't need the reset flag anymore after the fork. It has
2659 * fulfilled its duty:
2661 p->sched_reset_on_fork = 0;
2665 * Make sure we do not leak PI boosting priority to the child.
2667 p->prio = current->normal_prio;
2669 if (!rt_prio(p->prio))
2670 p->sched_class = &fair_sched_class;
2672 if (p->sched_class->task_fork)
2673 p->sched_class->task_fork(p);
2676 * The child is not yet in the pid-hash so no cgroup attach races,
2677 * and the cgroup is pinned to this child due to cgroup_fork()
2678 * is ran before sched_fork().
2680 * Silence PROVE_RCU.
2683 set_task_cpu(p, cpu);
2686 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2687 if (likely(sched_info_on()))
2688 memset(&p->sched_info, 0, sizeof(p->sched_info));
2690 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
2693 #ifdef CONFIG_PREEMPT
2694 /* Want to start with kernel preemption disabled. */
2695 task_thread_info(p)->preempt_count = 1;
2698 plist_node_init(&p->pushable_tasks, MAX_PRIO);
2705 * wake_up_new_task - wake up a newly created task for the first time.
2707 * This function will do some initial scheduler statistics housekeeping
2708 * that must be done for every newly created context, then puts the task
2709 * on the runqueue and wakes it.
2711 void wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
2713 unsigned long flags;
2715 int cpu __maybe_unused = get_cpu();
2718 rq = task_rq_lock(p, &flags);
2719 p->state = TASK_WAKING;
2722 * Fork balancing, do it here and not earlier because:
2723 * - cpus_allowed can change in the fork path
2724 * - any previously selected cpu might disappear through hotplug
2726 * We set TASK_WAKING so that select_task_rq() can drop rq->lock
2727 * without people poking at ->cpus_allowed.
2729 cpu = select_task_rq(rq, p, SD_BALANCE_FORK, 0);
2730 set_task_cpu(p, cpu);
2732 p->state = TASK_RUNNING;
2733 task_rq_unlock(rq, &flags);
2736 rq = task_rq_lock(p, &flags);
2737 activate_task(rq, p, 0);
2738 trace_sched_wakeup_new(p, 1);
2739 check_preempt_curr(rq, p, WF_FORK);
2741 if (p->sched_class->task_woken)
2742 p->sched_class->task_woken(rq, p);
2744 task_rq_unlock(rq, &flags);
2748 #ifdef CONFIG_PREEMPT_NOTIFIERS
2751 * preempt_notifier_register - tell me when current is being preempted & rescheduled
2752 * @notifier: notifier struct to register
2754 void preempt_notifier_register(struct preempt_notifier *notifier)
2756 hlist_add_head(¬ifier->link, ¤t->preempt_notifiers);
2758 EXPORT_SYMBOL_GPL(preempt_notifier_register);
2761 * preempt_notifier_unregister - no longer interested in preemption notifications
2762 * @notifier: notifier struct to unregister
2764 * This is safe to call from within a preemption notifier.
2766 void preempt_notifier_unregister(struct preempt_notifier *notifier)
2768 hlist_del(¬ifier->link);
2770 EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
2772 static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
2774 struct preempt_notifier *notifier;
2775 struct hlist_node *node;
2777 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
2778 notifier->ops->sched_in(notifier, raw_smp_processor_id());
2782 fire_sched_out_preempt_notifiers(struct task_struct *curr,
2783 struct task_struct *next)
2785 struct preempt_notifier *notifier;
2786 struct hlist_node *node;
2788 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
2789 notifier->ops->sched_out(notifier, next);
2792 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2794 static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
2799 fire_sched_out_preempt_notifiers(struct task_struct *curr,
2800 struct task_struct *next)
2804 #endif /* CONFIG_PREEMPT_NOTIFIERS */
2807 * prepare_task_switch - prepare to switch tasks
2808 * @rq: the runqueue preparing to switch
2809 * @prev: the current task that is being switched out
2810 * @next: the task we are going to switch to.
2812 * This is called with the rq lock held and interrupts off. It must
2813 * be paired with a subsequent finish_task_switch after the context
2816 * prepare_task_switch sets up locking and calls architecture specific
2820 prepare_task_switch(struct rq *rq, struct task_struct *prev,
2821 struct task_struct *next)
2823 sched_info_switch(prev, next);
2824 perf_event_task_sched_out(prev, next);
2825 fire_sched_out_preempt_notifiers(prev, next);
2826 prepare_lock_switch(rq, next);
2827 prepare_arch_switch(next);
2828 trace_sched_switch(prev, next);
2832 * finish_task_switch - clean up after a task-switch
2833 * @rq: runqueue associated with task-switch
2834 * @prev: the thread we just switched away from.
2836 * finish_task_switch must be called after the context switch, paired
2837 * with a prepare_task_switch call before the context switch.
2838 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2839 * and do any other architecture-specific cleanup actions.
2841 * Note that we may have delayed dropping an mm in context_switch(). If
2842 * so, we finish that here outside of the runqueue lock. (Doing it
2843 * with the lock held can cause deadlocks; see schedule() for
2846 static void finish_task_switch(struct rq *rq, struct task_struct *prev)
2847 __releases(rq->lock)
2849 struct mm_struct *mm = rq->prev_mm;
2855 * A task struct has one reference for the use as "current".
2856 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2857 * schedule one last time. The schedule call will never return, and
2858 * the scheduled task must drop that reference.
2859 * The test for TASK_DEAD must occur while the runqueue locks are
2860 * still held, otherwise prev could be scheduled on another cpu, die
2861 * there before we look at prev->state, and then the reference would
2863 * Manfred Spraul <manfred@colorfullife.com>
2865 prev_state = prev->state;
2866 finish_arch_switch(prev);
2867 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
2868 local_irq_disable();
2869 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
2870 perf_event_task_sched_in(current);
2871 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
2873 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
2874 finish_lock_switch(rq, prev);
2876 fire_sched_in_preempt_notifiers(current);
2879 if (unlikely(prev_state == TASK_DEAD)) {
2881 * Remove function-return probe instances associated with this
2882 * task and put them back on the free list.
2884 kprobe_flush_task(prev);
2885 put_task_struct(prev);
2891 /* assumes rq->lock is held */
2892 static inline void pre_schedule(struct rq *rq, struct task_struct *prev)
2894 if (prev->sched_class->pre_schedule)
2895 prev->sched_class->pre_schedule(rq, prev);
2898 /* rq->lock is NOT held, but preemption is disabled */
2899 static inline void post_schedule(struct rq *rq)
2901 if (rq->post_schedule) {
2902 unsigned long flags;
2904 raw_spin_lock_irqsave(&rq->lock, flags);
2905 if (rq->curr->sched_class->post_schedule)
2906 rq->curr->sched_class->post_schedule(rq);
2907 raw_spin_unlock_irqrestore(&rq->lock, flags);
2909 rq->post_schedule = 0;
2915 static inline void pre_schedule(struct rq *rq, struct task_struct *p)
2919 static inline void post_schedule(struct rq *rq)
2926 * schedule_tail - first thing a freshly forked thread must call.
2927 * @prev: the thread we just switched away from.
2929 asmlinkage void schedule_tail(struct task_struct *prev)
2930 __releases(rq->lock)
2932 struct rq *rq = this_rq();
2934 finish_task_switch(rq, prev);
2937 * FIXME: do we need to worry about rq being invalidated by the
2942 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2943 /* In this case, finish_task_switch does not reenable preemption */
2946 if (current->set_child_tid)
2947 put_user(task_pid_vnr(current), current->set_child_tid);
2951 * context_switch - switch to the new MM and the new
2952 * thread's register state.
2955 context_switch(struct rq *rq, struct task_struct *prev,
2956 struct task_struct *next)
2958 struct mm_struct *mm, *oldmm;
2960 prepare_task_switch(rq, prev, next);
2963 oldmm = prev->active_mm;
2965 * For paravirt, this is coupled with an exit in switch_to to
2966 * combine the page table reload and the switch backend into
2969 arch_start_context_switch(prev);
2972 next->active_mm = oldmm;
2973 atomic_inc(&oldmm->mm_count);
2974 enter_lazy_tlb(oldmm, next);
2976 switch_mm(oldmm, mm, next);
2979 prev->active_mm = NULL;
2980 rq->prev_mm = oldmm;
2983 * Since the runqueue lock will be released by the next
2984 * task (which is an invalid locking op but in the case
2985 * of the scheduler it's an obvious special-case), so we
2986 * do an early lockdep release here:
2988 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2989 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
2992 /* Here we just switch the register state and the stack. */
2993 switch_to(prev, next, prev);
2997 * this_rq must be evaluated again because prev may have moved
2998 * CPUs since it called schedule(), thus the 'rq' on its stack
2999 * frame will be invalid.
3001 finish_task_switch(this_rq(), prev);
3005 * nr_running, nr_uninterruptible and nr_context_switches:
3007 * externally visible scheduler statistics: current number of runnable
3008 * threads, current number of uninterruptible-sleeping threads, total
3009 * number of context switches performed since bootup.
3011 unsigned long nr_running(void)
3013 unsigned long i, sum = 0;
3015 for_each_online_cpu(i)
3016 sum += cpu_rq(i)->nr_running;
3021 unsigned long nr_uninterruptible(void)
3023 unsigned long i, sum = 0;
3025 for_each_possible_cpu(i)
3026 sum += cpu_rq(i)->nr_uninterruptible;
3029 * Since we read the counters lockless, it might be slightly
3030 * inaccurate. Do not allow it to go below zero though:
3032 if (unlikely((long)sum < 0))
3038 unsigned long long nr_context_switches(void)
3041 unsigned long long sum = 0;
3043 for_each_possible_cpu(i)
3044 sum += cpu_rq(i)->nr_switches;
3049 unsigned long nr_iowait(void)
3051 unsigned long i, sum = 0;
3053 for_each_possible_cpu(i)
3054 sum += atomic_read(&cpu_rq(i)->nr_iowait);
3059 unsigned long nr_iowait_cpu(int cpu)
3061 struct rq *this = cpu_rq(cpu);
3062 return atomic_read(&this->nr_iowait);
3065 unsigned long this_cpu_load(void)
3067 struct rq *this = this_rq();
3068 return this->cpu_load[0];
3072 /* Variables and functions for calc_load */
3073 static atomic_long_t calc_load_tasks;
3074 static unsigned long calc_load_update;
3075 unsigned long avenrun[3];
3076 EXPORT_SYMBOL(avenrun);
3078 static long calc_load_fold_active(struct rq *this_rq)
3080 long nr_active, delta = 0;
3082 nr_active = this_rq->nr_running;
3083 nr_active += (long) this_rq->nr_uninterruptible;
3085 if (nr_active != this_rq->calc_load_active) {
3086 delta = nr_active - this_rq->calc_load_active;
3087 this_rq->calc_load_active = nr_active;
3093 static unsigned long
3094 calc_load(unsigned long load, unsigned long exp, unsigned long active)
3097 load += active * (FIXED_1 - exp);
3098 load += 1UL << (FSHIFT - 1);
3099 return load >> FSHIFT;
3104 * For NO_HZ we delay the active fold to the next LOAD_FREQ update.
3106 * When making the ILB scale, we should try to pull this in as well.
3108 static atomic_long_t calc_load_tasks_idle;
3110 static void calc_load_account_idle(struct rq *this_rq)
3114 delta = calc_load_fold_active(this_rq);
3116 atomic_long_add(delta, &calc_load_tasks_idle);
3119 static long calc_load_fold_idle(void)
3124 * Its got a race, we don't care...
3126 if (atomic_long_read(&calc_load_tasks_idle))
3127 delta = atomic_long_xchg(&calc_load_tasks_idle, 0);
3133 * fixed_power_int - compute: x^n, in O(log n) time
3135 * @x: base of the power
3136 * @frac_bits: fractional bits of @x
3137 * @n: power to raise @x to.
3139 * By exploiting the relation between the definition of the natural power
3140 * function: x^n := x*x*...*x (x multiplied by itself for n times), and
3141 * the binary encoding of numbers used by computers: n := \Sum n_i * 2^i,
3142 * (where: n_i \elem {0, 1}, the binary vector representing n),
3143 * we find: x^n := x^(\Sum n_i * 2^i) := \Prod x^(n_i * 2^i), which is
3144 * of course trivially computable in O(log_2 n), the length of our binary
3147 static unsigned long
3148 fixed_power_int(unsigned long x, unsigned int frac_bits, unsigned int n)
3150 unsigned long result = 1UL << frac_bits;
3155 result += 1UL << (frac_bits - 1);
3156 result >>= frac_bits;
3162 x += 1UL << (frac_bits - 1);
3170 * a1 = a0 * e + a * (1 - e)
3172 * a2 = a1 * e + a * (1 - e)
3173 * = (a0 * e + a * (1 - e)) * e + a * (1 - e)
3174 * = a0 * e^2 + a * (1 - e) * (1 + e)
3176 * a3 = a2 * e + a * (1 - e)
3177 * = (a0 * e^2 + a * (1 - e) * (1 + e)) * e + a * (1 - e)
3178 * = a0 * e^3 + a * (1 - e) * (1 + e + e^2)
3182 * an = a0 * e^n + a * (1 - e) * (1 + e + ... + e^n-1) [1]
3183 * = a0 * e^n + a * (1 - e) * (1 - e^n)/(1 - e)
3184 * = a0 * e^n + a * (1 - e^n)
3186 * [1] application of the geometric series:
3189 * S_n := \Sum x^i = -------------
3192 static unsigned long
3193 calc_load_n(unsigned long load, unsigned long exp,
3194 unsigned long active, unsigned int n)
3197 return calc_load(load, fixed_power_int(exp, FSHIFT, n), active);
3201 * NO_HZ can leave us missing all per-cpu ticks calling
3202 * calc_load_account_active(), but since an idle CPU folds its delta into
3203 * calc_load_tasks_idle per calc_load_account_idle(), all we need to do is fold
3204 * in the pending idle delta if our idle period crossed a load cycle boundary.
3206 * Once we've updated the global active value, we need to apply the exponential
3207 * weights adjusted to the number of cycles missed.
3209 static void calc_global_nohz(unsigned long ticks)
3211 long delta, active, n;
3213 if (time_before(jiffies, calc_load_update))
3217 * If we crossed a calc_load_update boundary, make sure to fold
3218 * any pending idle changes, the respective CPUs might have
3219 * missed the tick driven calc_load_account_active() update
3222 delta = calc_load_fold_idle();
3224 atomic_long_add(delta, &calc_load_tasks);
3227 * If we were idle for multiple load cycles, apply them.
3229 if (ticks >= LOAD_FREQ) {
3230 n = ticks / LOAD_FREQ;
3232 active = atomic_long_read(&calc_load_tasks);
3233 active = active > 0 ? active * FIXED_1 : 0;
3235 avenrun[0] = calc_load_n(avenrun[0], EXP_1, active, n);
3236 avenrun[1] = calc_load_n(avenrun[1], EXP_5, active, n);
3237 avenrun[2] = calc_load_n(avenrun[2], EXP_15, active, n);
3239 calc_load_update += n * LOAD_FREQ;
3243 * Its possible the remainder of the above division also crosses
3244 * a LOAD_FREQ period, the regular check in calc_global_load()
3245 * which comes after this will take care of that.
3247 * Consider us being 11 ticks before a cycle completion, and us
3248 * sleeping for 4*LOAD_FREQ + 22 ticks, then the above code will
3249 * age us 4 cycles, and the test in calc_global_load() will
3250 * pick up the final one.
3254 static void calc_load_account_idle(struct rq *this_rq)
3258 static inline long calc_load_fold_idle(void)
3263 static void calc_global_nohz(unsigned long ticks)
3269 * get_avenrun - get the load average array
3270 * @loads: pointer to dest load array
3271 * @offset: offset to add
3272 * @shift: shift count to shift the result left
3274 * These values are estimates at best, so no need for locking.
3276 void get_avenrun(unsigned long *loads, unsigned long offset, int shift)
3278 loads[0] = (avenrun[0] + offset) << shift;
3279 loads[1] = (avenrun[1] + offset) << shift;
3280 loads[2] = (avenrun[2] + offset) << shift;
3284 * calc_load - update the avenrun load estimates 10 ticks after the
3285 * CPUs have updated calc_load_tasks.
3287 void calc_global_load(unsigned long ticks)
3291 calc_global_nohz(ticks);
3293 if (time_before(jiffies, calc_load_update + 10))
3296 active = atomic_long_read(&calc_load_tasks);
3297 active = active > 0 ? active * FIXED_1 : 0;
3299 avenrun[0] = calc_load(avenrun[0], EXP_1, active);
3300 avenrun[1] = calc_load(avenrun[1], EXP_5, active);
3301 avenrun[2] = calc_load(avenrun[2], EXP_15, active);
3303 calc_load_update += LOAD_FREQ;
3307 * Called from update_cpu_load() to periodically update this CPU's
3310 static void calc_load_account_active(struct rq *this_rq)
3314 if (time_before(jiffies, this_rq->calc_load_update))
3317 delta = calc_load_fold_active(this_rq);
3318 delta += calc_load_fold_idle();
3320 atomic_long_add(delta, &calc_load_tasks);
3322 this_rq->calc_load_update += LOAD_FREQ;
3326 * The exact cpuload at various idx values, calculated at every tick would be
3327 * load = (2^idx - 1) / 2^idx * load + 1 / 2^idx * cur_load
3329 * If a cpu misses updates for n-1 ticks (as it was idle) and update gets called
3330 * on nth tick when cpu may be busy, then we have:
3331 * load = ((2^idx - 1) / 2^idx)^(n-1) * load
3332 * load = (2^idx - 1) / 2^idx) * load + 1 / 2^idx * cur_load
3334 * decay_load_missed() below does efficient calculation of
3335 * load = ((2^idx - 1) / 2^idx)^(n-1) * load
3336 * avoiding 0..n-1 loop doing load = ((2^idx - 1) / 2^idx) * load
3338 * The calculation is approximated on a 128 point scale.
3339 * degrade_zero_ticks is the number of ticks after which load at any
3340 * particular idx is approximated to be zero.
3341 * degrade_factor is a precomputed table, a row for each load idx.
3342 * Each column corresponds to degradation factor for a power of two ticks,
3343 * based on 128 point scale.
3345 * row 2, col 3 (=12) says that the degradation at load idx 2 after
3346 * 8 ticks is 12/128 (which is an approximation of exact factor 3^8/4^8).
3348 * With this power of 2 load factors, we can degrade the load n times
3349 * by looking at 1 bits in n and doing as many mult/shift instead of
3350 * n mult/shifts needed by the exact degradation.
3352 #define DEGRADE_SHIFT 7
3353 static const unsigned char
3354 degrade_zero_ticks[CPU_LOAD_IDX_MAX] = {0, 8, 32, 64, 128};
3355 static const unsigned char
3356 degrade_factor[CPU_LOAD_IDX_MAX][DEGRADE_SHIFT + 1] = {
3357 {0, 0, 0, 0, 0, 0, 0, 0},
3358 {64, 32, 8, 0, 0, 0, 0, 0},
3359 {96, 72, 40, 12, 1, 0, 0},
3360 {112, 98, 75, 43, 15, 1, 0},
3361 {120, 112, 98, 76, 45, 16, 2} };
3364 * Update cpu_load for any missed ticks, due to tickless idle. The backlog
3365 * would be when CPU is idle and so we just decay the old load without
3366 * adding any new load.
3368 static unsigned long
3369 decay_load_missed(unsigned long load, unsigned long missed_updates, int idx)
3373 if (!missed_updates)
3376 if (missed_updates >= degrade_zero_ticks[idx])
3380 return load >> missed_updates;
3382 while (missed_updates) {
3383 if (missed_updates % 2)
3384 load = (load * degrade_factor[idx][j]) >> DEGRADE_SHIFT;
3386 missed_updates >>= 1;
3393 * Update rq->cpu_load[] statistics. This function is usually called every
3394 * scheduler tick (TICK_NSEC). With tickless idle this will not be called
3395 * every tick. We fix it up based on jiffies.
3397 static void update_cpu_load(struct rq *this_rq)
3399 unsigned long this_load = this_rq->load.weight;
3400 unsigned long curr_jiffies = jiffies;
3401 unsigned long pending_updates;
3404 this_rq->nr_load_updates++;
3406 /* Avoid repeated calls on same jiffy, when moving in and out of idle */
3407 if (curr_jiffies == this_rq->last_load_update_tick)
3410 pending_updates = curr_jiffies - this_rq->last_load_update_tick;
3411 this_rq->last_load_update_tick = curr_jiffies;
3413 /* Update our load: */
3414 this_rq->cpu_load[0] = this_load; /* Fasttrack for idx 0 */
3415 for (i = 1, scale = 2; i < CPU_LOAD_IDX_MAX; i++, scale += scale) {
3416 unsigned long old_load, new_load;
3418 /* scale is effectively 1 << i now, and >> i divides by scale */
3420 old_load = this_rq->cpu_load[i];
3421 old_load = decay_load_missed(old_load, pending_updates - 1, i);
3422 new_load = this_load;
3424 * Round up the averaging division if load is increasing. This
3425 * prevents us from getting stuck on 9 if the load is 10, for
3428 if (new_load > old_load)
3429 new_load += scale - 1;
3431 this_rq->cpu_load[i] = (old_load * (scale - 1) + new_load) >> i;
3434 sched_avg_update(this_rq);
3437 static void update_cpu_load_active(struct rq *this_rq)
3439 update_cpu_load(this_rq);
3441 calc_load_account_active(this_rq);
3447 * sched_exec - execve() is a valuable balancing opportunity, because at
3448 * this point the task has the smallest effective memory and cache footprint.
3450 void sched_exec(void)
3452 struct task_struct *p = current;
3453 unsigned long flags;
3457 rq = task_rq_lock(p, &flags);
3458 dest_cpu = p->sched_class->select_task_rq(rq, p, SD_BALANCE_EXEC, 0);
3459 if (dest_cpu == smp_processor_id())
3463 * select_task_rq() can race against ->cpus_allowed
3465 if (cpumask_test_cpu(dest_cpu, &p->cpus_allowed) &&
3466 likely(cpu_active(dest_cpu)) && migrate_task(p, rq)) {
3467 struct migration_arg arg = { p, dest_cpu };
3469 task_rq_unlock(rq, &flags);
3470 stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg);
3474 task_rq_unlock(rq, &flags);
3479 DEFINE_PER_CPU(struct kernel_stat, kstat);
3481 EXPORT_PER_CPU_SYMBOL(kstat);
3484 * Return any ns on the sched_clock that have not yet been accounted in
3485 * @p in case that task is currently running.
3487 * Called with task_rq_lock() held on @rq.
3489 static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq)
3493 if (task_current(rq, p)) {
3494 update_rq_clock(rq);
3495 ns = rq->clock_task - p->se.exec_start;
3503 unsigned long long task_delta_exec(struct task_struct *p)
3505 unsigned long flags;
3509 rq = task_rq_lock(p, &flags);
3510 ns = do_task_delta_exec(p, rq);
3511 task_rq_unlock(rq, &flags);
3517 * Return accounted runtime for the task.
3518 * In case the task is currently running, return the runtime plus current's
3519 * pending runtime that have not been accounted yet.
3521 unsigned long long task_sched_runtime(struct task_struct *p)
3523 unsigned long flags;
3527 rq = task_rq_lock(p, &flags);
3528 ns = p->se.sum_exec_runtime + do_task_delta_exec(p, rq);
3529 task_rq_unlock(rq, &flags);
3535 * Return sum_exec_runtime for the thread group.
3536 * In case the task is currently running, return the sum plus current's
3537 * pending runtime that have not been accounted yet.
3539 * Note that the thread group might have other running tasks as well,
3540 * so the return value not includes other pending runtime that other
3541 * running tasks might have.
3543 unsigned long long thread_group_sched_runtime(struct task_struct *p)
3545 struct task_cputime totals;
3546 unsigned long flags;
3550 rq = task_rq_lock(p, &flags);
3551 thread_group_cputime(p, &totals);
3552 ns = totals.sum_exec_runtime + do_task_delta_exec(p, rq);
3553 task_rq_unlock(rq, &flags);
3559 * Account user cpu time to a process.
3560 * @p: the process that the cpu time gets accounted to
3561 * @cputime: the cpu time spent in user space since the last update
3562 * @cputime_scaled: cputime scaled by cpu frequency
3564 void account_user_time(struct task_struct *p, cputime_t cputime,
3565 cputime_t cputime_scaled)
3567 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
3570 /* Add user time to process. */
3571 p->utime = cputime_add(p->utime, cputime);
3572 p->utimescaled = cputime_add(p->utimescaled, cputime_scaled);
3573 account_group_user_time(p, cputime);
3575 /* Add user time to cpustat. */
3576 tmp = cputime_to_cputime64(cputime);
3577 if (TASK_NICE(p) > 0)
3578 cpustat->nice = cputime64_add(cpustat->nice, tmp);
3580 cpustat->user = cputime64_add(cpustat->user, tmp);
3582 cpuacct_update_stats(p, CPUACCT_STAT_USER, cputime);
3583 /* Account for user time used */
3584 acct_update_integrals(p);
3588 * Account guest cpu time to a process.
3589 * @p: the process that the cpu time gets accounted to
3590 * @cputime: the cpu time spent in virtual machine since the last update
3591 * @cputime_scaled: cputime scaled by cpu frequency
3593 static void account_guest_time(struct task_struct *p, cputime_t cputime,
3594 cputime_t cputime_scaled)
3597 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
3599 tmp = cputime_to_cputime64(cputime);
3601 /* Add guest time to process. */
3602 p->utime = cputime_add(p->utime, cputime);
3603 p->utimescaled = cputime_add(p->utimescaled, cputime_scaled);
3604 account_group_user_time(p, cputime);
3605 p->gtime = cputime_add(p->gtime, cputime);
3607 /* Add guest time to cpustat. */
3608 if (TASK_NICE(p) > 0) {
3609 cpustat->nice = cputime64_add(cpustat->nice, tmp);
3610 cpustat->guest_nice = cputime64_add(cpustat->guest_nice, tmp);
3612 cpustat->user = cputime64_add(cpustat->user, tmp);
3613 cpustat->guest = cputime64_add(cpustat->guest, tmp);
3618 * Account system cpu time to a process and desired cpustat field
3619 * @p: the process that the cpu time gets accounted to
3620 * @cputime: the cpu time spent in kernel space since the last update
3621 * @cputime_scaled: cputime scaled by cpu frequency
3622 * @target_cputime64: pointer to cpustat field that has to be updated
3625 void __account_system_time(struct task_struct *p, cputime_t cputime,
3626 cputime_t cputime_scaled, cputime64_t *target_cputime64)
3628 cputime64_t tmp = cputime_to_cputime64(cputime);
3630 /* Add system time to process. */
3631 p->stime = cputime_add(p->stime, cputime);
3632 p->stimescaled = cputime_add(p->stimescaled, cputime_scaled);
3633 account_group_system_time(p, cputime);
3635 /* Add system time to cpustat. */
3636 *target_cputime64 = cputime64_add(*target_cputime64, tmp);
3637 cpuacct_update_stats(p, CPUACCT_STAT_SYSTEM, cputime);
3639 /* Account for system time used */
3640 acct_update_integrals(p);
3644 * Account system cpu time to a process.
3645 * @p: the process that the cpu time gets accounted to
3646 * @hardirq_offset: the offset to subtract from hardirq_count()
3647 * @cputime: the cpu time spent in kernel space since the last update
3648 * @cputime_scaled: cputime scaled by cpu frequency
3650 void account_system_time(struct task_struct *p, int hardirq_offset,
3651 cputime_t cputime, cputime_t cputime_scaled)
3653 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
3654 cputime64_t *target_cputime64;
3656 if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
3657 account_guest_time(p, cputime, cputime_scaled);
3661 if (hardirq_count() - hardirq_offset)
3662 target_cputime64 = &cpustat->irq;
3663 else if (in_serving_softirq())
3664 target_cputime64 = &cpustat->softirq;
3666 target_cputime64 = &cpustat->system;
3668 __account_system_time(p, cputime, cputime_scaled, target_cputime64);
3672 * Account for involuntary wait time.
3673 * @cputime: the cpu time spent in involuntary wait
3675 void account_steal_time(cputime_t cputime)
3677 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
3678 cputime64_t cputime64 = cputime_to_cputime64(cputime);
3680 cpustat->steal = cputime64_add(cpustat->steal, cputime64);
3684 * Account for idle time.
3685 * @cputime: the cpu time spent in idle wait
3687 void account_idle_time(cputime_t cputime)
3689 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
3690 cputime64_t cputime64 = cputime_to_cputime64(cputime);
3691 struct rq *rq = this_rq();
3693 if (atomic_read(&rq->nr_iowait) > 0)
3694 cpustat->iowait = cputime64_add(cpustat->iowait, cputime64);
3696 cpustat->idle = cputime64_add(cpustat->idle, cputime64);
3699 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
3701 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
3703 * Account a tick to a process and cpustat
3704 * @p: the process that the cpu time gets accounted to
3705 * @user_tick: is the tick from userspace
3706 * @rq: the pointer to rq
3708 * Tick demultiplexing follows the order
3709 * - pending hardirq update
3710 * - pending softirq update
3714 * - check for guest_time
3715 * - else account as system_time
3717 * Check for hardirq is done both for system and user time as there is
3718 * no timer going off while we are on hardirq and hence we may never get an
3719 * opportunity to update it solely in system time.
3720 * p->stime and friends are only updated on system time and not on irq
3721 * softirq as those do not count in task exec_runtime any more.
3723 static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
3726 cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);
3727 cputime64_t tmp = cputime_to_cputime64(cputime_one_jiffy);
3728 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
3730 if (irqtime_account_hi_update()) {
3731 cpustat->irq = cputime64_add(cpustat->irq, tmp);
3732 } else if (irqtime_account_si_update()) {
3733 cpustat->softirq = cputime64_add(cpustat->softirq, tmp);
3734 } else if (this_cpu_ksoftirqd() == p) {
3736 * ksoftirqd time do not get accounted in cpu_softirq_time.
3737 * So, we have to handle it separately here.
3738 * Also, p->stime needs to be updated for ksoftirqd.
3740 __account_system_time(p, cputime_one_jiffy, one_jiffy_scaled,
3742 } else if (user_tick) {
3743 account_user_time(p, cputime_one_jiffy, one_jiffy_scaled);
3744 } else if (p == rq->idle) {
3745 account_idle_time(cputime_one_jiffy);
3746 } else if (p->flags & PF_VCPU) { /* System time or guest time */
3747 account_guest_time(p, cputime_one_jiffy, one_jiffy_scaled);
3749 __account_system_time(p, cputime_one_jiffy, one_jiffy_scaled,
3754 static void irqtime_account_idle_ticks(int ticks)
3757 struct rq *rq = this_rq();
3759 for (i = 0; i < ticks; i++)
3760 irqtime_account_process_tick(current, 0, rq);
3762 #else /* CONFIG_IRQ_TIME_ACCOUNTING */
3763 static void irqtime_account_idle_ticks(int ticks) {}
3764 static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
3766 #endif /* CONFIG_IRQ_TIME_ACCOUNTING */
3769 * Account a single tick of cpu time.
3770 * @p: the process that the cpu time gets accounted to
3771 * @user_tick: indicates if the tick is a user or a system tick
3773 void account_process_tick(struct task_struct *p, int user_tick)
3775 cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);
3776 struct rq *rq = this_rq();
3778 if (sched_clock_irqtime) {
3779 irqtime_account_process_tick(p, user_tick, rq);
3784 account_user_time(p, cputime_one_jiffy, one_jiffy_scaled);
3785 else if ((p != rq->idle) || (irq_count() != HARDIRQ_OFFSET))
3786 account_system_time(p, HARDIRQ_OFFSET, cputime_one_jiffy,
3789 account_idle_time(cputime_one_jiffy);
3793 * Account multiple ticks of steal time.
3794 * @p: the process from which the cpu time has been stolen
3795 * @ticks: number of stolen ticks
3797 void account_steal_ticks(unsigned long ticks)
3799 account_steal_time(jiffies_to_cputime(ticks));
3803 * Account multiple ticks of idle time.
3804 * @ticks: number of stolen ticks
3806 void account_idle_ticks(unsigned long ticks)
3809 if (sched_clock_irqtime) {
3810 irqtime_account_idle_ticks(ticks);
3814 account_idle_time(jiffies_to_cputime(ticks));
3820 * Use precise platform statistics if available:
3822 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
3823 void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
3829 void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
3831 struct task_cputime cputime;
3833 thread_group_cputime(p, &cputime);
3835 *ut = cputime.utime;
3836 *st = cputime.stime;
3840 #ifndef nsecs_to_cputime
3841 # define nsecs_to_cputime(__nsecs) nsecs_to_jiffies(__nsecs)
3844 void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
3846 cputime_t rtime, utime = p->utime, total = cputime_add(utime, p->stime);
3849 * Use CFS's precise accounting:
3851 rtime = nsecs_to_cputime(p->se.sum_exec_runtime);
3857 do_div(temp, total);
3858 utime = (cputime_t)temp;
3863 * Compare with previous values, to keep monotonicity:
3865 p->prev_utime = max(p->prev_utime, utime);
3866 p->prev_stime = max(p->prev_stime, cputime_sub(rtime, p->prev_utime));
3868 *ut = p->prev_utime;
3869 *st = p->prev_stime;
3873 * Must be called with siglock held.
3875 void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
3877 struct signal_struct *sig = p->signal;
3878 struct task_cputime cputime;
3879 cputime_t rtime, utime, total;
3881 thread_group_cputime(p, &cputime);
3883 total = cputime_add(cputime.utime, cputime.stime);
3884 rtime = nsecs_to_cputime(cputime.sum_exec_runtime);
3889 temp *= cputime.utime;
3890 do_div(temp, total);
3891 utime = (cputime_t)temp;
3895 sig->prev_utime = max(sig->prev_utime, utime);
3896 sig->prev_stime = max(sig->prev_stime,
3897 cputime_sub(rtime, sig->prev_utime));
3899 *ut = sig->prev_utime;
3900 *st = sig->prev_stime;
3905 * This function gets called by the timer code, with HZ frequency.
3906 * We call it with interrupts disabled.
3908 * It also gets called by the fork code, when changing the parent's
3911 void scheduler_tick(void)
3913 int cpu = smp_processor_id();
3914 struct rq *rq = cpu_rq(cpu);
3915 struct task_struct *curr = rq->curr;
3919 raw_spin_lock(&rq->lock);
3920 update_rq_clock(rq);
3921 update_cpu_load_active(rq);
3922 curr->sched_class->task_tick(rq, curr, 0);
3923 raw_spin_unlock(&rq->lock);
3925 perf_event_task_tick();
3928 rq->idle_at_tick = idle_cpu(cpu);
3929 trigger_load_balance(rq, cpu);
3933 notrace unsigned long get_parent_ip(unsigned long addr)
3935 if (in_lock_functions(addr)) {
3936 addr = CALLER_ADDR2;
3937 if (in_lock_functions(addr))
3938 addr = CALLER_ADDR3;
3943 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
3944 defined(CONFIG_PREEMPT_TRACER))
3946 void __kprobes add_preempt_count(int val)
3948 #ifdef CONFIG_DEBUG_PREEMPT
3952 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
3955 preempt_count() += val;
3956 #ifdef CONFIG_DEBUG_PREEMPT
3958 * Spinlock count overflowing soon?
3960 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
3963 if (preempt_count() == val)
3964 trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
3966 EXPORT_SYMBOL(add_preempt_count);
3968 void __kprobes sub_preempt_count(int val)
3970 #ifdef CONFIG_DEBUG_PREEMPT
3974 if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
3977 * Is the spinlock portion underflowing?
3979 if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
3980 !(preempt_count() & PREEMPT_MASK)))
3984 if (preempt_count() == val)
3985 trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
3986 preempt_count() -= val;
3988 EXPORT_SYMBOL(sub_preempt_count);
3993 * Print scheduling while atomic bug:
3995 static noinline void __schedule_bug(struct task_struct *prev)
3997 struct pt_regs *regs = get_irq_regs();
3999 printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
4000 prev->comm, prev->pid, preempt_count());
4002 debug_show_held_locks(prev);
4004 if (irqs_disabled())
4005 print_irqtrace_events(prev);
4014 * Various schedule()-time debugging checks and statistics:
4016 static inline void schedule_debug(struct task_struct *prev)
4019 * Test if we are atomic. Since do_exit() needs to call into
4020 * schedule() atomically, we ignore that path for now.
4021 * Otherwise, whine if we are scheduling when we should not be.
4023 if (unlikely(in_atomic_preempt_off() && !prev->exit_state))
4024 __schedule_bug(prev);
4026 profile_hit(SCHED_PROFILING, __builtin_return_address(0));
4028 schedstat_inc(this_rq(), sched_count);
4029 #ifdef CONFIG_SCHEDSTATS
4030 if (unlikely(prev->lock_depth >= 0)) {
4031 schedstat_inc(this_rq(), rq_sched_info.bkl_count);
4032 schedstat_inc(prev, sched_info.bkl_count);
4037 static void put_prev_task(struct rq *rq, struct task_struct *prev)
4040 update_rq_clock(rq);
4041 prev->sched_class->put_prev_task(rq, prev);
4045 * Pick up the highest-prio task:
4047 static inline struct task_struct *
4048 pick_next_task(struct rq *rq)
4050 const struct sched_class *class;
4051 struct task_struct *p;
4054 * Optimization: we know that if all tasks are in
4055 * the fair class we can call that function directly:
4057 if (likely(rq->nr_running == rq->cfs.nr_running)) {
4058 p = fair_sched_class.pick_next_task(rq);
4063 for_each_class(class) {
4064 p = class->pick_next_task(rq);
4069 BUG(); /* the idle class will always have a runnable task */
4073 * schedule() is the main scheduler function.
4075 asmlinkage void __sched schedule(void)
4077 struct task_struct *prev, *next;
4078 unsigned long *switch_count;
4084 cpu = smp_processor_id();
4086 rcu_note_context_switch(cpu);
4089 schedule_debug(prev);
4091 if (sched_feat(HRTICK))
4094 raw_spin_lock_irq(&rq->lock);
4096 switch_count = &prev->nivcsw;
4097 if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
4098 if (unlikely(signal_pending_state(prev->state, prev))) {
4099 prev->state = TASK_RUNNING;
4102 * If a worker is going to sleep, notify and
4103 * ask workqueue whether it wants to wake up a
4104 * task to maintain concurrency. If so, wake
4107 if (prev->flags & PF_WQ_WORKER) {
4108 struct task_struct *to_wakeup;
4110 to_wakeup = wq_worker_sleeping(prev, cpu);
4112 try_to_wake_up_local(to_wakeup);
4114 deactivate_task(rq, prev, DEQUEUE_SLEEP);
4116 switch_count = &prev->nvcsw;
4120 * If we are going to sleep and we have plugged IO queued, make
4121 * sure to submit it to avoid deadlocks.
4123 if (prev->state != TASK_RUNNING && blk_needs_flush_plug(prev)) {
4124 raw_spin_unlock(&rq->lock);
4125 blk_flush_plug(prev);
4126 raw_spin_lock(&rq->lock);
4129 pre_schedule(rq, prev);
4131 if (unlikely(!rq->nr_running))
4132 idle_balance(cpu, rq);
4134 put_prev_task(rq, prev);
4135 next = pick_next_task(rq);
4136 clear_tsk_need_resched(prev);
4137 rq->skip_clock_update = 0;
4139 if (likely(prev != next)) {
4144 context_switch(rq, prev, next); /* unlocks the rq */
4146 * The context switch have flipped the stack from under us
4147 * and restored the local variables which were saved when
4148 * this task called schedule() in the past. prev == current
4149 * is still correct, but it can be moved to another cpu/rq.
4151 cpu = smp_processor_id();
4154 raw_spin_unlock_irq(&rq->lock);
4158 preempt_enable_no_resched();
4162 EXPORT_SYMBOL(schedule);
4164 #ifdef CONFIG_MUTEX_SPIN_ON_OWNER
4166 * Look out! "owner" is an entirely speculative pointer
4167 * access and not reliable.
4169 int mutex_spin_on_owner(struct mutex *lock, struct thread_info *owner)
4174 if (!sched_feat(OWNER_SPIN))
4177 #ifdef CONFIG_DEBUG_PAGEALLOC
4179 * Need to access the cpu field knowing that
4180 * DEBUG_PAGEALLOC could have unmapped it if
4181 * the mutex owner just released it and exited.
4183 if (probe_kernel_address(&owner->cpu, cpu))
4190 * Even if the access succeeded (likely case),
4191 * the cpu field may no longer be valid.
4193 if (cpu >= nr_cpumask_bits)
4197 * We need to validate that we can do a
4198 * get_cpu() and that we have the percpu area.
4200 if (!cpu_online(cpu))
4207 * Owner changed, break to re-assess state.
4209 if (lock->owner != owner) {
4211 * If the lock has switched to a different owner,
4212 * we likely have heavy contention. Return 0 to quit
4213 * optimistic spinning and not contend further:
4221 * Is that owner really running on that cpu?
4223 if (task_thread_info(rq->curr) != owner || need_resched())
4226 arch_mutex_cpu_relax();
4233 #ifdef CONFIG_PREEMPT
4235 * this is the entry point to schedule() from in-kernel preemption
4236 * off of preempt_enable. Kernel preemptions off return from interrupt
4237 * occur there and call schedule directly.
4239 asmlinkage void __sched notrace preempt_schedule(void)
4241 struct thread_info *ti = current_thread_info();
4244 * If there is a non-zero preempt_count or interrupts are disabled,
4245 * we do not want to preempt the current task. Just return..
4247 if (likely(ti->preempt_count || irqs_disabled()))
4251 add_preempt_count_notrace(PREEMPT_ACTIVE);
4253 sub_preempt_count_notrace(PREEMPT_ACTIVE);
4256 * Check again in case we missed a preemption opportunity
4257 * between schedule and now.
4260 } while (need_resched());
4262 EXPORT_SYMBOL(preempt_schedule);
4265 * this is the entry point to schedule() from kernel preemption
4266 * off of irq context.
4267 * Note, that this is called and return with irqs disabled. This will
4268 * protect us against recursive calling from irq.
4270 asmlinkage void __sched preempt_schedule_irq(void)
4272 struct thread_info *ti = current_thread_info();
4274 /* Catch callers which need to be fixed */
4275 BUG_ON(ti->preempt_count || !irqs_disabled());
4278 add_preempt_count(PREEMPT_ACTIVE);
4281 local_irq_disable();
4282 sub_preempt_count(PREEMPT_ACTIVE);
4285 * Check again in case we missed a preemption opportunity
4286 * between schedule and now.
4289 } while (need_resched());
4292 #endif /* CONFIG_PREEMPT */
4294 int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags,
4297 return try_to_wake_up(curr->private, mode, wake_flags);
4299 EXPORT_SYMBOL(default_wake_function);
4302 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
4303 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
4304 * number) then we wake all the non-exclusive tasks and one exclusive task.
4306 * There are circumstances in which we can try to wake a task which has already
4307 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
4308 * zero in this (rare) case, and we handle it by continuing to scan the queue.
4310 static void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
4311 int nr_exclusive, int wake_flags, void *key)
4313 wait_queue_t *curr, *next;
4315 list_for_each_entry_safe(curr, next, &q->task_list, task_list) {
4316 unsigned flags = curr->flags;
4318 if (curr->func(curr, mode, wake_flags, key) &&
4319 (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive)
4325 * __wake_up - wake up threads blocked on a waitqueue.
4327 * @mode: which threads
4328 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4329 * @key: is directly passed to the wakeup function
4331 * It may be assumed that this function implies a write memory barrier before
4332 * changing the task state if and only if any tasks are woken up.
4334 void __wake_up(wait_queue_head_t *q, unsigned int mode,
4335 int nr_exclusive, void *key)
4337 unsigned long flags;
4339 spin_lock_irqsave(&q->lock, flags);
4340 __wake_up_common(q, mode, nr_exclusive, 0, key);
4341 spin_unlock_irqrestore(&q->lock, flags);
4343 EXPORT_SYMBOL(__wake_up);
4346 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
4348 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode)
4350 __wake_up_common(q, mode, 1, 0, NULL);
4352 EXPORT_SYMBOL_GPL(__wake_up_locked);
4354 void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key)
4356 __wake_up_common(q, mode, 1, 0, key);
4358 EXPORT_SYMBOL_GPL(__wake_up_locked_key);
4361 * __wake_up_sync_key - wake up threads blocked on a waitqueue.
4363 * @mode: which threads
4364 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4365 * @key: opaque value to be passed to wakeup targets
4367 * The sync wakeup differs that the waker knows that it will schedule
4368 * away soon, so while the target thread will be woken up, it will not
4369 * be migrated to another CPU - ie. the two threads are 'synchronized'
4370 * with each other. This can prevent needless bouncing between CPUs.
4372 * On UP it can prevent extra preemption.
4374 * It may be assumed that this function implies a write memory barrier before
4375 * changing the task state if and only if any tasks are woken up.
4377 void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode,
4378 int nr_exclusive, void *key)
4380 unsigned long flags;
4381 int wake_flags = WF_SYNC;
4386 if (unlikely(!nr_exclusive))
4389 spin_lock_irqsave(&q->lock, flags);
4390 __wake_up_common(q, mode, nr_exclusive, wake_flags, key);
4391 spin_unlock_irqrestore(&q->lock, flags);
4393 EXPORT_SYMBOL_GPL(__wake_up_sync_key);
4396 * __wake_up_sync - see __wake_up_sync_key()
4398 void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
4400 __wake_up_sync_key(q, mode, nr_exclusive, NULL);
4402 EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */
4405 * complete: - signals a single thread waiting on this completion
4406 * @x: holds the state of this particular completion
4408 * This will wake up a single thread waiting on this completion. Threads will be
4409 * awakened in the same order in which they were queued.
4411 * See also complete_all(), wait_for_completion() and related routines.
4413 * It may be assumed that this function implies a write memory barrier before
4414 * changing the task state if and only if any tasks are woken up.
4416 void complete(struct completion *x)
4418 unsigned long flags;
4420 spin_lock_irqsave(&x->wait.lock, flags);
4422 __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL);
4423 spin_unlock_irqrestore(&x->wait.lock, flags);
4425 EXPORT_SYMBOL(complete);
4428 * complete_all: - signals all threads waiting on this completion
4429 * @x: holds the state of this particular completion
4431 * This will wake up all threads waiting on this particular completion event.
4433 * It may be assumed that this function implies a write memory barrier before
4434 * changing the task state if and only if any tasks are woken up.
4436 void complete_all(struct completion *x)
4438 unsigned long flags;
4440 spin_lock_irqsave(&x->wait.lock, flags);
4441 x->done += UINT_MAX/2;
4442 __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL);
4443 spin_unlock_irqrestore(&x->wait.lock, flags);
4445 EXPORT_SYMBOL(complete_all);
4447 static inline long __sched
4448 do_wait_for_common(struct completion *x, long timeout, int state)
4451 DECLARE_WAITQUEUE(wait, current);
4453 __add_wait_queue_tail_exclusive(&x->wait, &wait);
4455 if (signal_pending_state(state, current)) {
4456 timeout = -ERESTARTSYS;
4459 __set_current_state(state);
4460 spin_unlock_irq(&x->wait.lock);
4461 timeout = schedule_timeout(timeout);
4462 spin_lock_irq(&x->wait.lock);
4463 } while (!x->done && timeout);
4464 __remove_wait_queue(&x->wait, &wait);
4469 return timeout ?: 1;
4473 wait_for_common(struct completion *x, long timeout, int state)
4477 spin_lock_irq(&x->wait.lock);
4478 timeout = do_wait_for_common(x, timeout, state);
4479 spin_unlock_irq(&x->wait.lock);
4484 * wait_for_completion: - waits for completion of a task
4485 * @x: holds the state of this particular completion
4487 * This waits to be signaled for completion of a specific task. It is NOT
4488 * interruptible and there is no timeout.
4490 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
4491 * and interrupt capability. Also see complete().
4493 void __sched wait_for_completion(struct completion *x)
4495 wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE);
4497 EXPORT_SYMBOL(wait_for_completion);
4500 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
4501 * @x: holds the state of this particular completion
4502 * @timeout: timeout value in jiffies
4504 * This waits for either a completion of a specific task to be signaled or for a
4505 * specified timeout to expire. The timeout is in jiffies. It is not
4508 unsigned long __sched
4509 wait_for_completion_timeout(struct completion *x, unsigned long timeout)
4511 return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE);
4513 EXPORT_SYMBOL(wait_for_completion_timeout);
4516 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
4517 * @x: holds the state of this particular completion
4519 * This waits for completion of a specific task to be signaled. It is
4522 int __sched wait_for_completion_interruptible(struct completion *x)
4524 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE);
4525 if (t == -ERESTARTSYS)
4529 EXPORT_SYMBOL(wait_for_completion_interruptible);
4532 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
4533 * @x: holds the state of this particular completion
4534 * @timeout: timeout value in jiffies
4536 * This waits for either a completion of a specific task to be signaled or for a
4537 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
4540 wait_for_completion_interruptible_timeout(struct completion *x,
4541 unsigned long timeout)
4543 return wait_for_common(x, timeout, TASK_INTERRUPTIBLE);
4545 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout);
4548 * wait_for_completion_killable: - waits for completion of a task (killable)
4549 * @x: holds the state of this particular completion
4551 * This waits to be signaled for completion of a specific task. It can be
4552 * interrupted by a kill signal.
4554 int __sched wait_for_completion_killable(struct completion *x)
4556 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE);
4557 if (t == -ERESTARTSYS)
4561 EXPORT_SYMBOL(wait_for_completion_killable);
4564 * wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable))
4565 * @x: holds the state of this particular completion
4566 * @timeout: timeout value in jiffies
4568 * This waits for either a completion of a specific task to be
4569 * signaled or for a specified timeout to expire. It can be
4570 * interrupted by a kill signal. The timeout is in jiffies.
4573 wait_for_completion_killable_timeout(struct completion *x,
4574 unsigned long timeout)
4576 return wait_for_common(x, timeout, TASK_KILLABLE);
4578 EXPORT_SYMBOL(wait_for_completion_killable_timeout);
4581 * try_wait_for_completion - try to decrement a completion without blocking
4582 * @x: completion structure
4584 * Returns: 0 if a decrement cannot be done without blocking
4585 * 1 if a decrement succeeded.
4587 * If a completion is being used as a counting completion,
4588 * attempt to decrement the counter without blocking. This
4589 * enables us to avoid waiting if the resource the completion
4590 * is protecting is not available.
4592 bool try_wait_for_completion(struct completion *x)
4594 unsigned long flags;
4597 spin_lock_irqsave(&x->wait.lock, flags);
4602 spin_unlock_irqrestore(&x->wait.lock, flags);
4605 EXPORT_SYMBOL(try_wait_for_completion);
4608 * completion_done - Test to see if a completion has any waiters
4609 * @x: completion structure
4611 * Returns: 0 if there are waiters (wait_for_completion() in progress)
4612 * 1 if there are no waiters.
4615 bool completion_done(struct completion *x)
4617 unsigned long flags;
4620 spin_lock_irqsave(&x->wait.lock, flags);
4623 spin_unlock_irqrestore(&x->wait.lock, flags);
4626 EXPORT_SYMBOL(completion_done);
4629 sleep_on_common(wait_queue_head_t *q, int state, long timeout)
4631 unsigned long flags;
4634 init_waitqueue_entry(&wait, current);
4636 __set_current_state(state);
4638 spin_lock_irqsave(&q->lock, flags);
4639 __add_wait_queue(q, &wait);
4640 spin_unlock(&q->lock);
4641 timeout = schedule_timeout(timeout);
4642 spin_lock_irq(&q->lock);
4643 __remove_wait_queue(q, &wait);
4644 spin_unlock_irqrestore(&q->lock, flags);
4649 void __sched interruptible_sleep_on(wait_queue_head_t *q)
4651 sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
4653 EXPORT_SYMBOL(interruptible_sleep_on);
4656 interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout)
4658 return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout);
4660 EXPORT_SYMBOL(interruptible_sleep_on_timeout);
4662 void __sched sleep_on(wait_queue_head_t *q)
4664 sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
4666 EXPORT_SYMBOL(sleep_on);
4668 long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout)
4670 return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout);
4672 EXPORT_SYMBOL(sleep_on_timeout);
4674 #ifdef CONFIG_RT_MUTEXES
4677 * rt_mutex_setprio - set the current priority of a task
4679 * @prio: prio value (kernel-internal form)
4681 * This function changes the 'effective' priority of a task. It does
4682 * not touch ->normal_prio like __setscheduler().
4684 * Used by the rt_mutex code to implement priority inheritance logic.
4686 void rt_mutex_setprio(struct task_struct *p, int prio)
4688 unsigned long flags;
4689 int oldprio, on_rq, running;
4691 const struct sched_class *prev_class;
4693 BUG_ON(prio < 0 || prio > MAX_PRIO);
4695 rq = task_rq_lock(p, &flags);
4697 trace_sched_pi_setprio(p, prio);
4699 prev_class = p->sched_class;
4700 on_rq = p->se.on_rq;
4701 running = task_current(rq, p);
4703 dequeue_task(rq, p, 0);
4705 p->sched_class->put_prev_task(rq, p);
4708 p->sched_class = &rt_sched_class;
4710 p->sched_class = &fair_sched_class;
4715 p->sched_class->set_curr_task(rq);
4717 enqueue_task(rq, p, oldprio < prio ? ENQUEUE_HEAD : 0);
4719 check_class_changed(rq, p, prev_class, oldprio);
4720 task_rq_unlock(rq, &flags);
4725 void set_user_nice(struct task_struct *p, long nice)
4727 int old_prio, delta, on_rq;
4728 unsigned long flags;
4731 if (TASK_NICE(p) == nice || nice < -20 || nice > 19)
4734 * We have to be careful, if called from sys_setpriority(),
4735 * the task might be in the middle of scheduling on another CPU.
4737 rq = task_rq_lock(p, &flags);
4739 * The RT priorities are set via sched_setscheduler(), but we still
4740 * allow the 'normal' nice value to be set - but as expected
4741 * it wont have any effect on scheduling until the task is
4742 * SCHED_FIFO/SCHED_RR:
4744 if (task_has_rt_policy(p)) {
4745 p->static_prio = NICE_TO_PRIO(nice);
4748 on_rq = p->se.on_rq;
4750 dequeue_task(rq, p, 0);
4752 p->static_prio = NICE_TO_PRIO(nice);
4755 p->prio = effective_prio(p);
4756 delta = p->prio - old_prio;
4759 enqueue_task(rq, p, 0);
4761 * If the task increased its priority or is running and
4762 * lowered its priority, then reschedule its CPU:
4764 if (delta < 0 || (delta > 0 && task_running(rq, p)))
4765 resched_task(rq->curr);
4768 task_rq_unlock(rq, &flags);
4770 EXPORT_SYMBOL(set_user_nice);
4773 * can_nice - check if a task can reduce its nice value
4777 int can_nice(const struct task_struct *p, const int nice)
4779 /* convert nice value [19,-20] to rlimit style value [1,40] */
4780 int nice_rlim = 20 - nice;
4782 return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) ||
4783 capable(CAP_SYS_NICE));
4786 #ifdef __ARCH_WANT_SYS_NICE
4789 * sys_nice - change the priority of the current process.
4790 * @increment: priority increment
4792 * sys_setpriority is a more generic, but much slower function that
4793 * does similar things.
4795 SYSCALL_DEFINE1(nice, int, increment)
4800 * Setpriority might change our priority at the same moment.
4801 * We don't have to worry. Conceptually one call occurs first
4802 * and we have a single winner.
4804 if (increment < -40)
4809 nice = TASK_NICE(current) + increment;
4815 if (increment < 0 && !can_nice(current, nice))
4818 retval = security_task_setnice(current, nice);
4822 set_user_nice(current, nice);
4829 * task_prio - return the priority value of a given task.
4830 * @p: the task in question.
4832 * This is the priority value as seen by users in /proc.
4833 * RT tasks are offset by -200. Normal tasks are centered
4834 * around 0, value goes from -16 to +15.
4836 int task_prio(const struct task_struct *p)
4838 return p->prio - MAX_RT_PRIO;
4842 * task_nice - return the nice value of a given task.
4843 * @p: the task in question.
4845 int task_nice(const struct task_struct *p)
4847 return TASK_NICE(p);
4849 EXPORT_SYMBOL(task_nice);
4852 * idle_cpu - is a given cpu idle currently?
4853 * @cpu: the processor in question.
4855 int idle_cpu(int cpu)
4857 return cpu_curr(cpu) == cpu_rq(cpu)->idle;
4861 * idle_task - return the idle task for a given cpu.
4862 * @cpu: the processor in question.
4864 struct task_struct *idle_task(int cpu)
4866 return cpu_rq(cpu)->idle;
4870 * find_process_by_pid - find a process with a matching PID value.
4871 * @pid: the pid in question.
4873 static struct task_struct *find_process_by_pid(pid_t pid)
4875 return pid ? find_task_by_vpid(pid) : current;
4878 /* Actually do priority change: must hold rq lock. */
4880 __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio)
4882 BUG_ON(p->se.on_rq);
4885 p->rt_priority = prio;
4886 p->normal_prio = normal_prio(p);
4887 /* we are holding p->pi_lock already */
4888 p->prio = rt_mutex_getprio(p);
4889 if (rt_prio(p->prio))
4890 p->sched_class = &rt_sched_class;
4892 p->sched_class = &fair_sched_class;
4897 * check the target process has a UID that matches the current process's
4899 static bool check_same_owner(struct task_struct *p)
4901 const struct cred *cred = current_cred(), *pcred;
4905 pcred = __task_cred(p);
4906 if (cred->user->user_ns == pcred->user->user_ns)
4907 match = (cred->euid == pcred->euid ||
4908 cred->euid == pcred->uid);
4915 static int __sched_setscheduler(struct task_struct *p, int policy,
4916 const struct sched_param *param, bool user)
4918 int retval, oldprio, oldpolicy = -1, on_rq, running;
4919 unsigned long flags;
4920 const struct sched_class *prev_class;
4924 /* may grab non-irq protected spin_locks */
4925 BUG_ON(in_interrupt());
4927 /* double check policy once rq lock held */
4929 reset_on_fork = p->sched_reset_on_fork;
4930 policy = oldpolicy = p->policy;
4932 reset_on_fork = !!(policy & SCHED_RESET_ON_FORK);
4933 policy &= ~SCHED_RESET_ON_FORK;
4935 if (policy != SCHED_FIFO && policy != SCHED_RR &&
4936 policy != SCHED_NORMAL && policy != SCHED_BATCH &&
4937 policy != SCHED_IDLE)
4942 * Valid priorities for SCHED_FIFO and SCHED_RR are
4943 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
4944 * SCHED_BATCH and SCHED_IDLE is 0.
4946 if (param->sched_priority < 0 ||
4947 (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) ||
4948 (!p->mm && param->sched_priority > MAX_RT_PRIO-1))
4950 if (rt_policy(policy) != (param->sched_priority != 0))
4954 * Allow unprivileged RT tasks to decrease priority:
4956 if (user && !capable(CAP_SYS_NICE)) {
4957 if (rt_policy(policy)) {
4958 unsigned long rlim_rtprio =
4959 task_rlimit(p, RLIMIT_RTPRIO);
4961 /* can't set/change the rt policy */
4962 if (policy != p->policy && !rlim_rtprio)
4965 /* can't increase priority */
4966 if (param->sched_priority > p->rt_priority &&
4967 param->sched_priority > rlim_rtprio)
4972 * Treat SCHED_IDLE as nice 20. Only allow a switch to
4973 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
4975 if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) {
4976 if (!can_nice(p, TASK_NICE(p)))
4980 /* can't change other user's priorities */
4981 if (!check_same_owner(p))
4984 /* Normal users shall not reset the sched_reset_on_fork flag */
4985 if (p->sched_reset_on_fork && !reset_on_fork)
4990 retval = security_task_setscheduler(p);
4996 * make sure no PI-waiters arrive (or leave) while we are
4997 * changing the priority of the task:
4999 raw_spin_lock_irqsave(&p->pi_lock, flags);
5001 * To be able to change p->policy safely, the appropriate
5002 * runqueue lock must be held.
5004 rq = __task_rq_lock(p);
5007 * Changing the policy of the stop threads its a very bad idea
5009 if (p == rq->stop) {
5010 __task_rq_unlock(rq);
5011 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
5016 * If not changing anything there's no need to proceed further:
5018 if (unlikely(policy == p->policy && (!rt_policy(policy) ||
5019 param->sched_priority == p->rt_priority))) {
5021 __task_rq_unlock(rq);
5022 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
5026 #ifdef CONFIG_RT_GROUP_SCHED
5029 * Do not allow realtime tasks into groups that have no runtime
5032 if (rt_bandwidth_enabled() && rt_policy(policy) &&
5033 task_group(p)->rt_bandwidth.rt_runtime == 0 &&
5034 !task_group_is_autogroup(task_group(p))) {
5035 __task_rq_unlock(rq);
5036 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
5042 /* recheck policy now with rq lock held */
5043 if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
5044 policy = oldpolicy = -1;
5045 __task_rq_unlock(rq);
5046 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
5049 on_rq = p->se.on_rq;
5050 running = task_current(rq, p);
5052 deactivate_task(rq, p, 0);
5054 p->sched_class->put_prev_task(rq, p);
5056 p->sched_reset_on_fork = reset_on_fork;
5059 prev_class = p->sched_class;
5060 __setscheduler(rq, p, policy, param->sched_priority);
5063 p->sched_class->set_curr_task(rq);
5065 activate_task(rq, p, 0);
5067 check_class_changed(rq, p, prev_class, oldprio);
5068 __task_rq_unlock(rq);
5069 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
5071 rt_mutex_adjust_pi(p);
5077 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
5078 * @p: the task in question.
5079 * @policy: new policy.
5080 * @param: structure containing the new RT priority.
5082 * NOTE that the task may be already dead.
5084 int sched_setscheduler(struct task_struct *p, int policy,
5085 const struct sched_param *param)
5087 return __sched_setscheduler(p, policy, param, true);
5089 EXPORT_SYMBOL_GPL(sched_setscheduler);
5092 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
5093 * @p: the task in question.
5094 * @policy: new policy.
5095 * @param: structure containing the new RT priority.
5097 * Just like sched_setscheduler, only don't bother checking if the
5098 * current context has permission. For example, this is needed in
5099 * stop_machine(): we create temporary high priority worker threads,
5100 * but our caller might not have that capability.
5102 int sched_setscheduler_nocheck(struct task_struct *p, int policy,
5103 const struct sched_param *param)
5105 return __sched_setscheduler(p, policy, param, false);
5109 do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
5111 struct sched_param lparam;
5112 struct task_struct *p;
5115 if (!param || pid < 0)
5117 if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
5122 p = find_process_by_pid(pid);
5124 retval = sched_setscheduler(p, policy, &lparam);
5131 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
5132 * @pid: the pid in question.
5133 * @policy: new policy.
5134 * @param: structure containing the new RT priority.
5136 SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy,
5137 struct sched_param __user *, param)
5139 /* negative values for policy are not valid */
5143 return do_sched_setscheduler(pid, policy, param);
5147 * sys_sched_setparam - set/change the RT priority of a thread
5148 * @pid: the pid in question.
5149 * @param: structure containing the new RT priority.
5151 SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param)
5153 return do_sched_setscheduler(pid, -1, param);
5157 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
5158 * @pid: the pid in question.
5160 SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid)
5162 struct task_struct *p;
5170 p = find_process_by_pid(pid);
5172 retval = security_task_getscheduler(p);
5175 | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0);
5182 * sys_sched_getparam - get the RT priority of a thread
5183 * @pid: the pid in question.
5184 * @param: structure containing the RT priority.
5186 SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param)
5188 struct sched_param lp;
5189 struct task_struct *p;
5192 if (!param || pid < 0)
5196 p = find_process_by_pid(pid);
5201 retval = security_task_getscheduler(p);
5205 lp.sched_priority = p->rt_priority;
5209 * This one might sleep, we cannot do it with a spinlock held ...
5211 retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;
5220 long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
5222 cpumask_var_t cpus_allowed, new_mask;
5223 struct task_struct *p;
5229 p = find_process_by_pid(pid);
5236 /* Prevent p going away */
5240 if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) {
5244 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
5246 goto out_free_cpus_allowed;
5249 if (!check_same_owner(p) && !task_ns_capable(p, CAP_SYS_NICE))
5252 retval = security_task_setscheduler(p);
5256 cpuset_cpus_allowed(p, cpus_allowed);
5257 cpumask_and(new_mask, in_mask, cpus_allowed);
5259 retval = set_cpus_allowed_ptr(p, new_mask);
5262 cpuset_cpus_allowed(p, cpus_allowed);
5263 if (!cpumask_subset(new_mask, cpus_allowed)) {
5265 * We must have raced with a concurrent cpuset
5266 * update. Just reset the cpus_allowed to the
5267 * cpuset's cpus_allowed
5269 cpumask_copy(new_mask, cpus_allowed);
5274 free_cpumask_var(new_mask);
5275 out_free_cpus_allowed:
5276 free_cpumask_var(cpus_allowed);
5283 static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
5284 struct cpumask *new_mask)
5286 if (len < cpumask_size())
5287 cpumask_clear(new_mask);
5288 else if (len > cpumask_size())
5289 len = cpumask_size();
5291 return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
5295 * sys_sched_setaffinity - set the cpu affinity of a process
5296 * @pid: pid of the process
5297 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5298 * @user_mask_ptr: user-space pointer to the new cpu mask
5300 SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len,
5301 unsigned long __user *, user_mask_ptr)
5303 cpumask_var_t new_mask;
5306 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
5309 retval = get_user_cpu_mask(user_mask_ptr, len, new_mask);
5311 retval = sched_setaffinity(pid, new_mask);
5312 free_cpumask_var(new_mask);
5316 long sched_getaffinity(pid_t pid, struct cpumask *mask)
5318 struct task_struct *p;
5319 unsigned long flags;
5327 p = find_process_by_pid(pid);
5331 retval = security_task_getscheduler(p);
5335 rq = task_rq_lock(p, &flags);
5336 cpumask_and(mask, &p->cpus_allowed, cpu_online_mask);
5337 task_rq_unlock(rq, &flags);
5347 * sys_sched_getaffinity - get the cpu affinity of a process
5348 * @pid: pid of the process
5349 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5350 * @user_mask_ptr: user-space pointer to hold the current cpu mask
5352 SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
5353 unsigned long __user *, user_mask_ptr)
5358 if ((len * BITS_PER_BYTE) < nr_cpu_ids)
5360 if (len & (sizeof(unsigned long)-1))
5363 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
5366 ret = sched_getaffinity(pid, mask);
5368 size_t retlen = min_t(size_t, len, cpumask_size());
5370 if (copy_to_user(user_mask_ptr, mask, retlen))
5375 free_cpumask_var(mask);
5381 * sys_sched_yield - yield the current processor to other threads.
5383 * This function yields the current CPU to other tasks. If there are no
5384 * other threads running on this CPU then this function will return.
5386 SYSCALL_DEFINE0(sched_yield)
5388 struct rq *rq = this_rq_lock();
5390 schedstat_inc(rq, yld_count);
5391 current->sched_class->yield_task(rq);
5394 * Since we are going to call schedule() anyway, there's
5395 * no need to preempt or enable interrupts:
5397 __release(rq->lock);
5398 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
5399 do_raw_spin_unlock(&rq->lock);
5400 preempt_enable_no_resched();
5407 static inline int should_resched(void)
5409 return need_resched() && !(preempt_count() & PREEMPT_ACTIVE);
5412 static void __cond_resched(void)
5414 add_preempt_count(PREEMPT_ACTIVE);
5416 sub_preempt_count(PREEMPT_ACTIVE);
5419 int __sched _cond_resched(void)
5421 if (should_resched()) {
5427 EXPORT_SYMBOL(_cond_resched);
5430 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
5431 * call schedule, and on return reacquire the lock.
5433 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
5434 * operations here to prevent schedule() from being called twice (once via
5435 * spin_unlock(), once by hand).
5437 int __cond_resched_lock(spinlock_t *lock)
5439 int resched = should_resched();
5442 lockdep_assert_held(lock);
5444 if (spin_needbreak(lock) || resched) {
5455 EXPORT_SYMBOL(__cond_resched_lock);
5457 int __sched __cond_resched_softirq(void)
5459 BUG_ON(!in_softirq());
5461 if (should_resched()) {
5469 EXPORT_SYMBOL(__cond_resched_softirq);
5472 * yield - yield the current processor to other threads.
5474 * This is a shortcut for kernel-space yielding - it marks the
5475 * thread runnable and calls sys_sched_yield().
5477 void __sched yield(void)
5479 set_current_state(TASK_RUNNING);
5482 EXPORT_SYMBOL(yield);
5485 * yield_to - yield the current processor to another thread in
5486 * your thread group, or accelerate that thread toward the
5487 * processor it's on.
5489 * @preempt: whether task preemption is allowed or not
5491 * It's the caller's job to ensure that the target task struct
5492 * can't go away on us before we can do any checks.
5494 * Returns true if we indeed boosted the target task.
5496 bool __sched yield_to(struct task_struct *p, bool preempt)
5498 struct task_struct *curr = current;
5499 struct rq *rq, *p_rq;
5500 unsigned long flags;
5503 local_irq_save(flags);
5508 double_rq_lock(rq, p_rq);
5509 while (task_rq(p) != p_rq) {
5510 double_rq_unlock(rq, p_rq);
5514 if (!curr->sched_class->yield_to_task)
5517 if (curr->sched_class != p->sched_class)
5520 if (task_running(p_rq, p) || p->state)
5523 yielded = curr->sched_class->yield_to_task(rq, p, preempt);
5525 schedstat_inc(rq, yld_count);
5527 * Make p's CPU reschedule; pick_next_entity takes care of
5530 if (preempt && rq != p_rq)
5531 resched_task(p_rq->curr);
5535 double_rq_unlock(rq, p_rq);
5536 local_irq_restore(flags);
5543 EXPORT_SYMBOL_GPL(yield_to);
5546 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
5547 * that process accounting knows that this is a task in IO wait state.
5549 void __sched io_schedule(void)
5551 struct rq *rq = raw_rq();
5553 delayacct_blkio_start();
5554 atomic_inc(&rq->nr_iowait);
5555 blk_flush_plug(current);
5556 current->in_iowait = 1;
5558 current->in_iowait = 0;
5559 atomic_dec(&rq->nr_iowait);
5560 delayacct_blkio_end();
5562 EXPORT_SYMBOL(io_schedule);
5564 long __sched io_schedule_timeout(long timeout)
5566 struct rq *rq = raw_rq();
5569 delayacct_blkio_start();
5570 atomic_inc(&rq->nr_iowait);
5571 blk_flush_plug(current);
5572 current->in_iowait = 1;
5573 ret = schedule_timeout(timeout);
5574 current->in_iowait = 0;
5575 atomic_dec(&rq->nr_iowait);
5576 delayacct_blkio_end();
5581 * sys_sched_get_priority_max - return maximum RT priority.
5582 * @policy: scheduling class.
5584 * this syscall returns the maximum rt_priority that can be used
5585 * by a given scheduling class.
5587 SYSCALL_DEFINE1(sched_get_priority_max, int, policy)
5594 ret = MAX_USER_RT_PRIO-1;
5606 * sys_sched_get_priority_min - return minimum RT priority.
5607 * @policy: scheduling class.
5609 * this syscall returns the minimum rt_priority that can be used
5610 * by a given scheduling class.
5612 SYSCALL_DEFINE1(sched_get_priority_min, int, policy)
5630 * sys_sched_rr_get_interval - return the default timeslice of a process.
5631 * @pid: pid of the process.
5632 * @interval: userspace pointer to the timeslice value.
5634 * this syscall writes the default timeslice value of a given process
5635 * into the user-space timespec buffer. A value of '0' means infinity.
5637 SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid,
5638 struct timespec __user *, interval)
5640 struct task_struct *p;
5641 unsigned int time_slice;
5642 unsigned long flags;
5652 p = find_process_by_pid(pid);
5656 retval = security_task_getscheduler(p);
5660 rq = task_rq_lock(p, &flags);
5661 time_slice = p->sched_class->get_rr_interval(rq, p);
5662 task_rq_unlock(rq, &flags);
5665 jiffies_to_timespec(time_slice, &t);
5666 retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;
5674 static const char stat_nam[] = TASK_STATE_TO_CHAR_STR;
5676 void sched_show_task(struct task_struct *p)
5678 unsigned long free = 0;
5681 state = p->state ? __ffs(p->state) + 1 : 0;
5682 printk(KERN_INFO "%-15.15s %c", p->comm,
5683 state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?');
5684 #if BITS_PER_LONG == 32
5685 if (state == TASK_RUNNING)
5686 printk(KERN_CONT " running ");
5688 printk(KERN_CONT " %08lx ", thread_saved_pc(p));
5690 if (state == TASK_RUNNING)
5691 printk(KERN_CONT " running task ");
5693 printk(KERN_CONT " %016lx ", thread_saved_pc(p));
5695 #ifdef CONFIG_DEBUG_STACK_USAGE
5696 free = stack_not_used(p);
5698 printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free,
5699 task_pid_nr(p), task_pid_nr(p->real_parent),
5700 (unsigned long)task_thread_info(p)->flags);
5702 show_stack(p, NULL);
5705 void show_state_filter(unsigned long state_filter)
5707 struct task_struct *g, *p;
5709 #if BITS_PER_LONG == 32
5711 " task PC stack pid father\n");
5714 " task PC stack pid father\n");
5716 read_lock(&tasklist_lock);
5717 do_each_thread(g, p) {
5719 * reset the NMI-timeout, listing all files on a slow
5720 * console might take a lot of time:
5722 touch_nmi_watchdog();
5723 if (!state_filter || (p->state & state_filter))
5725 } while_each_thread(g, p);
5727 touch_all_softlockup_watchdogs();
5729 #ifdef CONFIG_SCHED_DEBUG
5730 sysrq_sched_debug_show();
5732 read_unlock(&tasklist_lock);
5734 * Only show locks if all tasks are dumped:
5737 debug_show_all_locks();
5740 void __cpuinit init_idle_bootup_task(struct task_struct *idle)
5742 idle->sched_class = &idle_sched_class;
5746 * init_idle - set up an idle thread for a given CPU
5747 * @idle: task in question
5748 * @cpu: cpu the idle task belongs to
5750 * NOTE: this function does not set the idle thread's NEED_RESCHED
5751 * flag, to make booting more robust.
5753 void __cpuinit init_idle(struct task_struct *idle, int cpu)
5755 struct rq *rq = cpu_rq(cpu);
5756 unsigned long flags;
5758 raw_spin_lock_irqsave(&rq->lock, flags);
5761 idle->state = TASK_RUNNING;
5762 idle->se.exec_start = sched_clock();
5764 cpumask_copy(&idle->cpus_allowed, cpumask_of(cpu));
5766 * We're having a chicken and egg problem, even though we are
5767 * holding rq->lock, the cpu isn't yet set to this cpu so the
5768 * lockdep check in task_group() will fail.
5770 * Similar case to sched_fork(). / Alternatively we could
5771 * use task_rq_lock() here and obtain the other rq->lock.
5776 __set_task_cpu(idle, cpu);
5779 rq->curr = rq->idle = idle;
5780 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
5783 raw_spin_unlock_irqrestore(&rq->lock, flags);
5785 /* Set the preempt count _outside_ the spinlocks! */
5786 #if defined(CONFIG_PREEMPT)
5787 task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0);
5789 task_thread_info(idle)->preempt_count = 0;
5792 * The idle tasks have their own, simple scheduling class:
5794 idle->sched_class = &idle_sched_class;
5795 ftrace_graph_init_idle_task(idle, cpu);
5799 * In a system that switches off the HZ timer nohz_cpu_mask
5800 * indicates which cpus entered this state. This is used
5801 * in the rcu update to wait only for active cpus. For system
5802 * which do not switch off the HZ timer nohz_cpu_mask should
5803 * always be CPU_BITS_NONE.
5805 cpumask_var_t nohz_cpu_mask;
5808 * Increase the granularity value when there are more CPUs,
5809 * because with more CPUs the 'effective latency' as visible
5810 * to users decreases. But the relationship is not linear,
5811 * so pick a second-best guess by going with the log2 of the
5814 * This idea comes from the SD scheduler of Con Kolivas:
5816 static int get_update_sysctl_factor(void)
5818 unsigned int cpus = min_t(int, num_online_cpus(), 8);
5819 unsigned int factor;
5821 switch (sysctl_sched_tunable_scaling) {
5822 case SCHED_TUNABLESCALING_NONE:
5825 case SCHED_TUNABLESCALING_LINEAR:
5828 case SCHED_TUNABLESCALING_LOG:
5830 factor = 1 + ilog2(cpus);
5837 static void update_sysctl(void)
5839 unsigned int factor = get_update_sysctl_factor();
5841 #define SET_SYSCTL(name) \
5842 (sysctl_##name = (factor) * normalized_sysctl_##name)
5843 SET_SYSCTL(sched_min_granularity);
5844 SET_SYSCTL(sched_latency);
5845 SET_SYSCTL(sched_wakeup_granularity);
5849 static inline void sched_init_granularity(void)
5856 * This is how migration works:
5858 * 1) we invoke migration_cpu_stop() on the target CPU using
5860 * 2) stopper starts to run (implicitly forcing the migrated thread
5862 * 3) it checks whether the migrated task is still in the wrong runqueue.
5863 * 4) if it's in the wrong runqueue then the migration thread removes
5864 * it and puts it into the right queue.
5865 * 5) stopper completes and stop_one_cpu() returns and the migration
5870 * Change a given task's CPU affinity. Migrate the thread to a
5871 * proper CPU and schedule it away if the CPU it's executing on
5872 * is removed from the allowed bitmask.
5874 * NOTE: the caller must have a valid reference to the task, the
5875 * task must not exit() & deallocate itself prematurely. The
5876 * call is not atomic; no spinlocks may be held.
5878 int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
5880 unsigned long flags;
5882 unsigned int dest_cpu;
5886 * Serialize against TASK_WAKING so that ttwu() and wunt() can
5887 * drop the rq->lock and still rely on ->cpus_allowed.
5890 while (task_is_waking(p))
5892 rq = task_rq_lock(p, &flags);
5893 if (task_is_waking(p)) {
5894 task_rq_unlock(rq, &flags);
5898 if (!cpumask_intersects(new_mask, cpu_active_mask)) {
5903 if (unlikely((p->flags & PF_THREAD_BOUND) && p != current &&
5904 !cpumask_equal(&p->cpus_allowed, new_mask))) {
5909 if (p->sched_class->set_cpus_allowed)
5910 p->sched_class->set_cpus_allowed(p, new_mask);
5912 cpumask_copy(&p->cpus_allowed, new_mask);
5913 p->rt.nr_cpus_allowed = cpumask_weight(new_mask);
5916 /* Can the task run on the task's current CPU? If so, we're done */
5917 if (cpumask_test_cpu(task_cpu(p), new_mask))
5920 dest_cpu = cpumask_any_and(cpu_active_mask, new_mask);
5921 if (migrate_task(p, rq)) {
5922 struct migration_arg arg = { p, dest_cpu };
5923 /* Need help from migration thread: drop lock and wait. */
5924 task_rq_unlock(rq, &flags);
5925 stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg);
5926 tlb_migrate_finish(p->mm);
5930 task_rq_unlock(rq, &flags);
5934 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
5937 * Move (not current) task off this cpu, onto dest cpu. We're doing
5938 * this because either it can't run here any more (set_cpus_allowed()
5939 * away from this CPU, or CPU going down), or because we're
5940 * attempting to rebalance this task on exec (sched_exec).
5942 * So we race with normal scheduler movements, but that's OK, as long
5943 * as the task is no longer on this CPU.
5945 * Returns non-zero if task was successfully migrated.
5947 static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
5949 struct rq *rq_dest, *rq_src;
5952 if (unlikely(!cpu_active(dest_cpu)))
5955 rq_src = cpu_rq(src_cpu);
5956 rq_dest = cpu_rq(dest_cpu);
5958 double_rq_lock(rq_src, rq_dest);
5959 /* Already moved. */
5960 if (task_cpu(p) != src_cpu)
5962 /* Affinity changed (again). */
5963 if (!cpumask_test_cpu(dest_cpu, &p->cpus_allowed))
5967 * If we're not on a rq, the next wake-up will ensure we're
5971 deactivate_task(rq_src, p, 0);
5972 set_task_cpu(p, dest_cpu);
5973 activate_task(rq_dest, p, 0);
5974 check_preempt_curr(rq_dest, p, 0);
5979 double_rq_unlock(rq_src, rq_dest);
5984 * migration_cpu_stop - this will be executed by a highprio stopper thread
5985 * and performs thread migration by bumping thread off CPU then
5986 * 'pushing' onto another runqueue.
5988 static int migration_cpu_stop(void *data)
5990 struct migration_arg *arg = data;
5993 * The original target cpu might have gone down and we might
5994 * be on another cpu but it doesn't matter.
5996 local_irq_disable();
5997 __migrate_task(arg->task, raw_smp_processor_id(), arg->dest_cpu);
6002 #ifdef CONFIG_HOTPLUG_CPU
6005 * Ensures that the idle task is using init_mm right before its cpu goes
6008 void idle_task_exit(void)
6010 struct mm_struct *mm = current->active_mm;
6012 BUG_ON(cpu_online(smp_processor_id()));
6015 switch_mm(mm, &init_mm, current);
6020 * While a dead CPU has no uninterruptible tasks queued at this point,
6021 * it might still have a nonzero ->nr_uninterruptible counter, because
6022 * for performance reasons the counter is not stricly tracking tasks to
6023 * their home CPUs. So we just add the counter to another CPU's counter,
6024 * to keep the global sum constant after CPU-down:
6026 static void migrate_nr_uninterruptible(struct rq *rq_src)
6028 struct rq *rq_dest = cpu_rq(cpumask_any(cpu_active_mask));
6030 rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible;
6031 rq_src->nr_uninterruptible = 0;
6035 * remove the tasks which were accounted by rq from calc_load_tasks.
6037 static void calc_global_load_remove(struct rq *rq)
6039 atomic_long_sub(rq->calc_load_active, &calc_load_tasks);
6040 rq->calc_load_active = 0;
6044 * Migrate all tasks from the rq, sleeping tasks will be migrated by
6045 * try_to_wake_up()->select_task_rq().
6047 * Called with rq->lock held even though we'er in stop_machine() and
6048 * there's no concurrency possible, we hold the required locks anyway
6049 * because of lock validation efforts.
6051 static void migrate_tasks(unsigned int dead_cpu)
6053 struct rq *rq = cpu_rq(dead_cpu);
6054 struct task_struct *next, *stop = rq->stop;
6058 * Fudge the rq selection such that the below task selection loop
6059 * doesn't get stuck on the currently eligible stop task.
6061 * We're currently inside stop_machine() and the rq is either stuck
6062 * in the stop_machine_cpu_stop() loop, or we're executing this code,
6063 * either way we should never end up calling schedule() until we're
6070 * There's this thread running, bail when that's the only
6073 if (rq->nr_running == 1)
6076 next = pick_next_task(rq);
6078 next->sched_class->put_prev_task(rq, next);
6080 /* Find suitable destination for @next, with force if needed. */
6081 dest_cpu = select_fallback_rq(dead_cpu, next);
6082 raw_spin_unlock(&rq->lock);
6084 __migrate_task(next, dead_cpu, dest_cpu);
6086 raw_spin_lock(&rq->lock);
6092 #endif /* CONFIG_HOTPLUG_CPU */
6094 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
6096 static struct ctl_table sd_ctl_dir[] = {
6098 .procname = "sched_domain",
6104 static struct ctl_table sd_ctl_root[] = {
6106 .procname = "kernel",
6108 .child = sd_ctl_dir,
6113 static struct ctl_table *sd_alloc_ctl_entry(int n)
6115 struct ctl_table *entry =
6116 kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL);
6121 static void sd_free_ctl_entry(struct ctl_table **tablep)
6123 struct ctl_table *entry;
6126 * In the intermediate directories, both the child directory and
6127 * procname are dynamically allocated and could fail but the mode
6128 * will always be set. In the lowest directory the names are
6129 * static strings and all have proc handlers.
6131 for (entry = *tablep; entry->mode; entry++) {
6133 sd_free_ctl_entry(&entry->child);
6134 if (entry->proc_handler == NULL)
6135 kfree(entry->procname);
6143 set_table_entry(struct ctl_table *entry,
6144 const char *procname, void *data, int maxlen,
6145 mode_t mode, proc_handler *proc_handler)
6147 entry->procname = procname;
6149 entry->maxlen = maxlen;
6151 entry->proc_handler = proc_handler;
6154 static struct ctl_table *
6155 sd_alloc_ctl_domain_table(struct sched_domain *sd)
6157 struct ctl_table *table = sd_alloc_ctl_entry(13);
6162 set_table_entry(&table[0], "min_interval", &sd->min_interval,
6163 sizeof(long), 0644, proc_doulongvec_minmax);
6164 set_table_entry(&table[1], "max_interval", &sd->max_interval,
6165 sizeof(long), 0644, proc_doulongvec_minmax);
6166 set_table_entry(&table[2], "busy_idx", &sd->busy_idx,
6167 sizeof(int), 0644, proc_dointvec_minmax);
6168 set_table_entry(&table[3], "idle_idx", &sd->idle_idx,
6169 sizeof(int), 0644, proc_dointvec_minmax);
6170 set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx,
6171 sizeof(int), 0644, proc_dointvec_minmax);
6172 set_table_entry(&table[5], "wake_idx", &sd->wake_idx,
6173 sizeof(int), 0644, proc_dointvec_minmax);
6174 set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx,
6175 sizeof(int), 0644, proc_dointvec_minmax);
6176 set_table_entry(&table[7], "busy_factor", &sd->busy_factor,
6177 sizeof(int), 0644, proc_dointvec_minmax);
6178 set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct,
6179 sizeof(int), 0644, proc_dointvec_minmax);
6180 set_table_entry(&table[9], "cache_nice_tries",
6181 &sd->cache_nice_tries,
6182 sizeof(int), 0644, proc_dointvec_minmax);
6183 set_table_entry(&table[10], "flags", &sd->flags,
6184 sizeof(int), 0644, proc_dointvec_minmax);
6185 set_table_entry(&table[11], "name", sd->name,
6186 CORENAME_MAX_SIZE, 0444, proc_dostring);
6187 /* &table[12] is terminator */
6192 static ctl_table *sd_alloc_ctl_cpu_table(int cpu)
6194 struct ctl_table *entry, *table;
6195 struct sched_domain *sd;
6196 int domain_num = 0, i;
6199 for_each_domain(cpu, sd)
6201 entry = table = sd_alloc_ctl_entry(domain_num + 1);
6206 for_each_domain(cpu, sd) {
6207 snprintf(buf, 32, "domain%d", i);
6208 entry->procname = kstrdup(buf, GFP_KERNEL);
6210 entry->child = sd_alloc_ctl_domain_table(sd);
6217 static struct ctl_table_header *sd_sysctl_header;
6218 static void register_sched_domain_sysctl(void)
6220 int i, cpu_num = num_possible_cpus();
6221 struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1);
6224 WARN_ON(sd_ctl_dir[0].child);
6225 sd_ctl_dir[0].child = entry;
6230 for_each_possible_cpu(i) {
6231 snprintf(buf, 32, "cpu%d", i);
6232 entry->procname = kstrdup(buf, GFP_KERNEL);
6234 entry->child = sd_alloc_ctl_cpu_table(i);
6238 WARN_ON(sd_sysctl_header);
6239 sd_sysctl_header = register_sysctl_table(sd_ctl_root);
6242 /* may be called multiple times per register */
6243 static void unregister_sched_domain_sysctl(void)
6245 if (sd_sysctl_header)
6246 unregister_sysctl_table(sd_sysctl_header);
6247 sd_sysctl_header = NULL;
6248 if (sd_ctl_dir[0].child)
6249 sd_free_ctl_entry(&sd_ctl_dir[0].child);
6252 static void register_sched_domain_sysctl(void)
6255 static void unregister_sched_domain_sysctl(void)
6260 static void set_rq_online(struct rq *rq)
6263 const struct sched_class *class;
6265 cpumask_set_cpu(rq->cpu, rq->rd->online);
6268 for_each_class(class) {
6269 if (class->rq_online)
6270 class->rq_online(rq);
6275 static void set_rq_offline(struct rq *rq)
6278 const struct sched_class *class;
6280 for_each_class(class) {
6281 if (class->rq_offline)
6282 class->rq_offline(rq);
6285 cpumask_clear_cpu(rq->cpu, rq->rd->online);
6291 * migration_call - callback that gets triggered when a CPU is added.
6292 * Here we can start up the necessary migration thread for the new CPU.
6294 static int __cpuinit
6295 migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
6297 int cpu = (long)hcpu;
6298 unsigned long flags;
6299 struct rq *rq = cpu_rq(cpu);
6301 switch (action & ~CPU_TASKS_FROZEN) {
6303 case CPU_UP_PREPARE:
6304 rq->calc_load_update = calc_load_update;
6308 /* Update our root-domain */
6309 raw_spin_lock_irqsave(&rq->lock, flags);
6311 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
6315 raw_spin_unlock_irqrestore(&rq->lock, flags);
6318 #ifdef CONFIG_HOTPLUG_CPU
6320 /* Update our root-domain */
6321 raw_spin_lock_irqsave(&rq->lock, flags);
6323 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
6327 BUG_ON(rq->nr_running != 1); /* the migration thread */
6328 raw_spin_unlock_irqrestore(&rq->lock, flags);
6330 migrate_nr_uninterruptible(rq);
6331 calc_global_load_remove(rq);
6336 update_max_interval();
6342 * Register at high priority so that task migration (migrate_all_tasks)
6343 * happens before everything else. This has to be lower priority than
6344 * the notifier in the perf_event subsystem, though.
6346 static struct notifier_block __cpuinitdata migration_notifier = {
6347 .notifier_call = migration_call,
6348 .priority = CPU_PRI_MIGRATION,
6351 static int __cpuinit sched_cpu_active(struct notifier_block *nfb,
6352 unsigned long action, void *hcpu)
6354 switch (action & ~CPU_TASKS_FROZEN) {
6356 case CPU_DOWN_FAILED:
6357 set_cpu_active((long)hcpu, true);
6364 static int __cpuinit sched_cpu_inactive(struct notifier_block *nfb,
6365 unsigned long action, void *hcpu)
6367 switch (action & ~CPU_TASKS_FROZEN) {
6368 case CPU_DOWN_PREPARE:
6369 set_cpu_active((long)hcpu, false);
6376 static int __init migration_init(void)
6378 void *cpu = (void *)(long)smp_processor_id();
6381 /* Initialize migration for the boot CPU */
6382 err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
6383 BUG_ON(err == NOTIFY_BAD);
6384 migration_call(&migration_notifier, CPU_ONLINE, cpu);
6385 register_cpu_notifier(&migration_notifier);
6387 /* Register cpu active notifiers */
6388 cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE);
6389 cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE);
6393 early_initcall(migration_init);
6398 static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */
6400 #ifdef CONFIG_SCHED_DEBUG
6402 static __read_mostly int sched_domain_debug_enabled;
6404 static int __init sched_domain_debug_setup(char *str)
6406 sched_domain_debug_enabled = 1;
6410 early_param("sched_debug", sched_domain_debug_setup);
6412 static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
6413 struct cpumask *groupmask)
6415 struct sched_group *group = sd->groups;
6418 cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd));
6419 cpumask_clear(groupmask);
6421 printk(KERN_DEBUG "%*s domain %d: ", level, "", level);
6423 if (!(sd->flags & SD_LOAD_BALANCE)) {
6424 printk("does not load-balance\n");
6426 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain"
6431 printk(KERN_CONT "span %s level %s\n", str, sd->name);
6433 if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) {
6434 printk(KERN_ERR "ERROR: domain->span does not contain "
6437 if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) {
6438 printk(KERN_ERR "ERROR: domain->groups does not contain"
6442 printk(KERN_DEBUG "%*s groups:", level + 1, "");
6446 printk(KERN_ERR "ERROR: group is NULL\n");
6450 if (!group->cpu_power) {
6451 printk(KERN_CONT "\n");
6452 printk(KERN_ERR "ERROR: domain->cpu_power not "
6457 if (!cpumask_weight(sched_group_cpus(group))) {
6458 printk(KERN_CONT "\n");
6459 printk(KERN_ERR "ERROR: empty group\n");
6463 if (cpumask_intersects(groupmask, sched_group_cpus(group))) {
6464 printk(KERN_CONT "\n");
6465 printk(KERN_ERR "ERROR: repeated CPUs\n");
6469 cpumask_or(groupmask, groupmask, sched_group_cpus(group));
6471 cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group));
6473 printk(KERN_CONT " %s", str);
6474 if (group->cpu_power != SCHED_LOAD_SCALE) {
6475 printk(KERN_CONT " (cpu_power = %d)",
6479 group = group->next;
6480 } while (group != sd->groups);
6481 printk(KERN_CONT "\n");
6483 if (!cpumask_equal(sched_domain_span(sd), groupmask))
6484 printk(KERN_ERR "ERROR: groups don't span domain->span\n");
6487 !cpumask_subset(groupmask, sched_domain_span(sd->parent)))
6488 printk(KERN_ERR "ERROR: parent span is not a superset "
6489 "of domain->span\n");
6493 static void sched_domain_debug(struct sched_domain *sd, int cpu)
6497 if (!sched_domain_debug_enabled)
6501 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
6505 printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu);
6508 if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask))
6516 #else /* !CONFIG_SCHED_DEBUG */
6517 # define sched_domain_debug(sd, cpu) do { } while (0)
6518 #endif /* CONFIG_SCHED_DEBUG */
6520 static int sd_degenerate(struct sched_domain *sd)
6522 if (cpumask_weight(sched_domain_span(sd)) == 1)
6525 /* Following flags need at least 2 groups */
6526 if (sd->flags & (SD_LOAD_BALANCE |
6527 SD_BALANCE_NEWIDLE |
6531 SD_SHARE_PKG_RESOURCES)) {
6532 if (sd->groups != sd->groups->next)
6536 /* Following flags don't use groups */
6537 if (sd->flags & (SD_WAKE_AFFINE))
6544 sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
6546 unsigned long cflags = sd->flags, pflags = parent->flags;
6548 if (sd_degenerate(parent))
6551 if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent)))
6554 /* Flags needing groups don't count if only 1 group in parent */
6555 if (parent->groups == parent->groups->next) {
6556 pflags &= ~(SD_LOAD_BALANCE |
6557 SD_BALANCE_NEWIDLE |
6561 SD_SHARE_PKG_RESOURCES);
6562 if (nr_node_ids == 1)
6563 pflags &= ~SD_SERIALIZE;
6565 if (~cflags & pflags)
6571 static void free_rootdomain(struct rcu_head *rcu)
6573 struct root_domain *rd = container_of(rcu, struct root_domain, rcu);
6575 cpupri_cleanup(&rd->cpupri);
6576 free_cpumask_var(rd->rto_mask);
6577 free_cpumask_var(rd->online);
6578 free_cpumask_var(rd->span);
6582 static void rq_attach_root(struct rq *rq, struct root_domain *rd)
6584 struct root_domain *old_rd = NULL;
6585 unsigned long flags;
6587 raw_spin_lock_irqsave(&rq->lock, flags);
6592 if (cpumask_test_cpu(rq->cpu, old_rd->online))
6595 cpumask_clear_cpu(rq->cpu, old_rd->span);
6598 * If we dont want to free the old_rt yet then
6599 * set old_rd to NULL to skip the freeing later
6602 if (!atomic_dec_and_test(&old_rd->refcount))
6606 atomic_inc(&rd->refcount);
6609 cpumask_set_cpu(rq->cpu, rd->span);
6610 if (cpumask_test_cpu(rq->cpu, cpu_active_mask))
6613 raw_spin_unlock_irqrestore(&rq->lock, flags);
6616 call_rcu_sched(&old_rd->rcu, free_rootdomain);
6619 static int init_rootdomain(struct root_domain *rd)
6621 memset(rd, 0, sizeof(*rd));
6623 if (!alloc_cpumask_var(&rd->span, GFP_KERNEL))
6625 if (!alloc_cpumask_var(&rd->online, GFP_KERNEL))
6627 if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL))
6630 if (cpupri_init(&rd->cpupri) != 0)
6635 free_cpumask_var(rd->rto_mask);
6637 free_cpumask_var(rd->online);
6639 free_cpumask_var(rd->span);
6644 static void init_defrootdomain(void)
6646 init_rootdomain(&def_root_domain);
6648 atomic_set(&def_root_domain.refcount, 1);
6651 static struct root_domain *alloc_rootdomain(void)
6653 struct root_domain *rd;
6655 rd = kmalloc(sizeof(*rd), GFP_KERNEL);
6659 if (init_rootdomain(rd) != 0) {
6667 static void free_sched_domain(struct rcu_head *rcu)
6669 struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu);
6670 if (atomic_dec_and_test(&sd->groups->ref))
6675 static void destroy_sched_domain(struct sched_domain *sd, int cpu)
6677 call_rcu(&sd->rcu, free_sched_domain);
6680 static void destroy_sched_domains(struct sched_domain *sd, int cpu)
6682 for (; sd; sd = sd->parent)
6683 destroy_sched_domain(sd, cpu);
6687 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
6688 * hold the hotplug lock.
6691 cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
6693 struct rq *rq = cpu_rq(cpu);
6694 struct sched_domain *tmp;
6696 /* Remove the sched domains which do not contribute to scheduling. */
6697 for (tmp = sd; tmp; ) {
6698 struct sched_domain *parent = tmp->parent;
6702 if (sd_parent_degenerate(tmp, parent)) {
6703 tmp->parent = parent->parent;
6705 parent->parent->child = tmp;
6706 destroy_sched_domain(parent, cpu);
6711 if (sd && sd_degenerate(sd)) {
6714 destroy_sched_domain(tmp, cpu);
6719 sched_domain_debug(sd, cpu);
6721 rq_attach_root(rq, rd);
6723 rcu_assign_pointer(rq->sd, sd);
6724 destroy_sched_domains(tmp, cpu);
6727 /* cpus with isolated domains */
6728 static cpumask_var_t cpu_isolated_map;
6730 /* Setup the mask of cpus configured for isolated domains */
6731 static int __init isolated_cpu_setup(char *str)
6733 alloc_bootmem_cpumask_var(&cpu_isolated_map);
6734 cpulist_parse(str, cpu_isolated_map);
6738 __setup("isolcpus=", isolated_cpu_setup);
6740 #define SD_NODES_PER_DOMAIN 16
6745 * find_next_best_node - find the next node to include in a sched_domain
6746 * @node: node whose sched_domain we're building
6747 * @used_nodes: nodes already in the sched_domain
6749 * Find the next node to include in a given scheduling domain. Simply
6750 * finds the closest node not already in the @used_nodes map.
6752 * Should use nodemask_t.
6754 static int find_next_best_node(int node, nodemask_t *used_nodes)
6756 int i, n, val, min_val, best_node = 0;
6760 for (i = 0; i < nr_node_ids; i++) {
6761 /* Start at @node */
6762 n = (node + i) % nr_node_ids;
6764 if (!nr_cpus_node(n))
6767 /* Skip already used nodes */
6768 if (node_isset(n, *used_nodes))
6771 /* Simple min distance search */
6772 val = node_distance(node, n);
6774 if (val < min_val) {
6780 node_set(best_node, *used_nodes);
6785 * sched_domain_node_span - get a cpumask for a node's sched_domain
6786 * @node: node whose cpumask we're constructing
6787 * @span: resulting cpumask
6789 * Given a node, construct a good cpumask for its sched_domain to span. It
6790 * should be one that prevents unnecessary balancing, but also spreads tasks
6793 static void sched_domain_node_span(int node, struct cpumask *span)
6795 nodemask_t used_nodes;
6798 cpumask_clear(span);
6799 nodes_clear(used_nodes);
6801 cpumask_or(span, span, cpumask_of_node(node));
6802 node_set(node, used_nodes);
6804 for (i = 1; i < SD_NODES_PER_DOMAIN; i++) {
6805 int next_node = find_next_best_node(node, &used_nodes);
6807 cpumask_or(span, span, cpumask_of_node(next_node));
6811 static const struct cpumask *cpu_node_mask(int cpu)
6813 lockdep_assert_held(&sched_domains_mutex);
6815 sched_domain_node_span(cpu_to_node(cpu), sched_domains_tmpmask);
6817 return sched_domains_tmpmask;
6820 static const struct cpumask *cpu_allnodes_mask(int cpu)
6822 return cpu_possible_mask;
6824 #endif /* CONFIG_NUMA */
6826 static const struct cpumask *cpu_cpu_mask(int cpu)
6828 return cpumask_of_node(cpu_to_node(cpu));
6831 int sched_smt_power_savings = 0, sched_mc_power_savings = 0;
6834 struct sched_domain **__percpu sd;
6835 struct sched_group **__percpu sg;
6839 struct sched_domain ** __percpu sd;
6840 struct root_domain *rd;
6850 struct sched_domain_topology_level;
6852 typedef struct sched_domain *(*sched_domain_init_f)(struct sched_domain_topology_level *tl, int cpu);
6853 typedef const struct cpumask *(*sched_domain_mask_f)(int cpu);
6855 struct sched_domain_topology_level {
6856 sched_domain_init_f init;
6857 sched_domain_mask_f mask;
6858 struct sd_data data;
6862 * Assumes the sched_domain tree is fully constructed
6864 static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg)
6866 struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu);
6867 struct sched_domain *child = sd->child;
6870 cpu = cpumask_first(sched_domain_span(child));
6873 *sg = *per_cpu_ptr(sdd->sg, cpu);
6879 * build_sched_groups takes the cpumask we wish to span, and a pointer
6880 * to a function which identifies what group(along with sched group) a CPU
6881 * belongs to. The return value of group_fn must be a >= 0 and < nr_cpu_ids
6882 * (due to the fact that we keep track of groups covered with a struct cpumask).
6884 * build_sched_groups will build a circular linked list of the groups
6885 * covered by the given span, and will set each group's ->cpumask correctly,
6886 * and ->cpu_power to 0.
6889 build_sched_groups(struct sched_domain *sd)
6891 struct sched_group *first = NULL, *last = NULL;
6892 struct sd_data *sdd = sd->private;
6893 const struct cpumask *span = sched_domain_span(sd);
6894 struct cpumask *covered;
6897 lockdep_assert_held(&sched_domains_mutex);
6898 covered = sched_domains_tmpmask;
6900 cpumask_clear(covered);
6902 for_each_cpu(i, span) {
6903 struct sched_group *sg;
6904 int group = get_group(i, sdd, &sg);
6907 if (cpumask_test_cpu(i, covered))
6910 cpumask_clear(sched_group_cpus(sg));
6913 for_each_cpu(j, span) {
6914 if (get_group(j, sdd, NULL) != group)
6917 cpumask_set_cpu(j, covered);
6918 cpumask_set_cpu(j, sched_group_cpus(sg));
6931 * Initialize sched groups cpu_power.
6933 * cpu_power indicates the capacity of sched group, which is used while
6934 * distributing the load between different sched groups in a sched domain.
6935 * Typically cpu_power for all the groups in a sched domain will be same unless
6936 * there are asymmetries in the topology. If there are asymmetries, group
6937 * having more cpu_power will pickup more load compared to the group having
6940 static void init_sched_groups_power(int cpu, struct sched_domain *sd)
6942 WARN_ON(!sd || !sd->groups);
6944 if (cpu != group_first_cpu(sd->groups))
6947 sd->groups->group_weight = cpumask_weight(sched_group_cpus(sd->groups));
6949 update_group_power(sd, cpu);
6953 * Initializers for schedule domains
6954 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
6957 #ifdef CONFIG_SCHED_DEBUG
6958 # define SD_INIT_NAME(sd, type) sd->name = #type
6960 # define SD_INIT_NAME(sd, type) do { } while (0)
6963 #define SD_INIT_FUNC(type) \
6964 static noinline struct sched_domain * \
6965 sd_init_##type(struct sched_domain_topology_level *tl, int cpu) \
6967 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); \
6968 *sd = SD_##type##_INIT; \
6969 sd->level = SD_LV_##type; \
6970 SD_INIT_NAME(sd, type); \
6971 sd->private = &tl->data; \
6977 SD_INIT_FUNC(ALLNODES)
6980 #ifdef CONFIG_SCHED_SMT
6981 SD_INIT_FUNC(SIBLING)
6983 #ifdef CONFIG_SCHED_MC
6986 #ifdef CONFIG_SCHED_BOOK
6990 static int default_relax_domain_level = -1;
6992 static int __init setup_relax_domain_level(char *str)
6996 val = simple_strtoul(str, NULL, 0);
6997 if (val < SD_LV_MAX)
6998 default_relax_domain_level = val;
7002 __setup("relax_domain_level=", setup_relax_domain_level);
7004 static void set_domain_attribute(struct sched_domain *sd,
7005 struct sched_domain_attr *attr)
7009 if (!attr || attr->relax_domain_level < 0) {
7010 if (default_relax_domain_level < 0)
7013 request = default_relax_domain_level;
7015 request = attr->relax_domain_level;
7016 if (request < sd->level) {
7017 /* turn off idle balance on this domain */
7018 sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
7020 /* turn on idle balance on this domain */
7021 sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
7025 static void __sdt_free(const struct cpumask *cpu_map);
7026 static int __sdt_alloc(const struct cpumask *cpu_map);
7028 static void __free_domain_allocs(struct s_data *d, enum s_alloc what,
7029 const struct cpumask *cpu_map)
7033 if (!atomic_read(&d->rd->refcount))
7034 free_rootdomain(&d->rd->rcu); /* fall through */
7036 free_percpu(d->sd); /* fall through */
7038 __sdt_free(cpu_map); /* fall through */
7044 static enum s_alloc __visit_domain_allocation_hell(struct s_data *d,
7045 const struct cpumask *cpu_map)
7047 memset(d, 0, sizeof(*d));
7049 if (__sdt_alloc(cpu_map))
7050 return sa_sd_storage;
7051 d->sd = alloc_percpu(struct sched_domain *);
7053 return sa_sd_storage;
7054 d->rd = alloc_rootdomain();
7057 return sa_rootdomain;
7061 * NULL the sd_data elements we've used to build the sched_domain and
7062 * sched_group structure so that the subsequent __free_domain_allocs()
7063 * will not free the data we're using.
7065 static void claim_allocations(int cpu, struct sched_domain *sd)
7067 struct sd_data *sdd = sd->private;
7068 struct sched_group *sg = sd->groups;
7070 WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd);
7071 *per_cpu_ptr(sdd->sd, cpu) = NULL;
7073 if (cpu == cpumask_first(sched_group_cpus(sg))) {
7074 WARN_ON_ONCE(*per_cpu_ptr(sdd->sg, cpu) != sg);
7075 *per_cpu_ptr(sdd->sg, cpu) = NULL;
7079 #ifdef CONFIG_SCHED_SMT
7080 static const struct cpumask *cpu_smt_mask(int cpu)
7082 return topology_thread_cpumask(cpu);
7087 * Topology list, bottom-up.
7089 static struct sched_domain_topology_level default_topology[] = {
7090 #ifdef CONFIG_SCHED_SMT
7091 { sd_init_SIBLING, cpu_smt_mask, },
7093 #ifdef CONFIG_SCHED_MC
7094 { sd_init_MC, cpu_coregroup_mask, },
7096 #ifdef CONFIG_SCHED_BOOK
7097 { sd_init_BOOK, cpu_book_mask, },
7099 { sd_init_CPU, cpu_cpu_mask, },
7101 { sd_init_NODE, cpu_node_mask, },
7102 { sd_init_ALLNODES, cpu_allnodes_mask, },
7107 static struct sched_domain_topology_level *sched_domain_topology = default_topology;
7109 static int __sdt_alloc(const struct cpumask *cpu_map)
7111 struct sched_domain_topology_level *tl;
7114 for (tl = sched_domain_topology; tl->init; tl++) {
7115 struct sd_data *sdd = &tl->data;
7117 sdd->sd = alloc_percpu(struct sched_domain *);
7121 sdd->sg = alloc_percpu(struct sched_group *);
7125 for_each_cpu(j, cpu_map) {
7126 struct sched_domain *sd;
7127 struct sched_group *sg;
7129 sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(),
7130 GFP_KERNEL, cpu_to_node(j));
7134 *per_cpu_ptr(sdd->sd, j) = sd;
7136 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
7137 GFP_KERNEL, cpu_to_node(j));
7141 *per_cpu_ptr(sdd->sg, j) = sg;
7148 static void __sdt_free(const struct cpumask *cpu_map)
7150 struct sched_domain_topology_level *tl;
7153 for (tl = sched_domain_topology; tl->init; tl++) {
7154 struct sd_data *sdd = &tl->data;
7156 for_each_cpu(j, cpu_map) {
7157 kfree(*per_cpu_ptr(sdd->sd, j));
7158 kfree(*per_cpu_ptr(sdd->sg, j));
7160 free_percpu(sdd->sd);
7161 free_percpu(sdd->sg);
7165 struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl,
7166 struct s_data *d, const struct cpumask *cpu_map,
7167 struct sched_domain_attr *attr, struct sched_domain *child,
7170 struct sched_domain *sd = tl->init(tl, cpu);
7174 set_domain_attribute(sd, attr);
7175 cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu));
7184 * Build sched domains for a given set of cpus and attach the sched domains
7185 * to the individual cpus
7187 static int build_sched_domains(const struct cpumask *cpu_map,
7188 struct sched_domain_attr *attr)
7190 enum s_alloc alloc_state = sa_none;
7191 struct sched_domain *sd;
7193 int i, ret = -ENOMEM;
7195 alloc_state = __visit_domain_allocation_hell(&d, cpu_map);
7196 if (alloc_state != sa_rootdomain)
7199 /* Set up domains for cpus specified by the cpu_map. */
7200 for_each_cpu(i, cpu_map) {
7201 struct sched_domain_topology_level *tl;
7204 for (tl = sched_domain_topology; tl->init; tl++)
7205 sd = build_sched_domain(tl, &d, cpu_map, attr, sd, i);
7210 *per_cpu_ptr(d.sd, i) = sd;
7213 /* Build the groups for the domains */
7214 for_each_cpu(i, cpu_map) {
7215 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
7216 sd->span_weight = cpumask_weight(sched_domain_span(sd));
7217 get_group(i, sd->private, &sd->groups);
7218 atomic_inc(&sd->groups->ref);
7220 if (i != cpumask_first(sched_domain_span(sd)))
7223 build_sched_groups(sd);
7227 /* Calculate CPU power for physical packages and nodes */
7228 for (i = nr_cpumask_bits-1; i >= 0; i--) {
7229 if (!cpumask_test_cpu(i, cpu_map))
7232 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
7233 claim_allocations(i, sd);
7234 init_sched_groups_power(i, sd);
7238 /* Attach the domains */
7240 for_each_cpu(i, cpu_map) {
7241 sd = *per_cpu_ptr(d.sd, i);
7242 cpu_attach_domain(sd, d.rd, i);
7248 __free_domain_allocs(&d, alloc_state, cpu_map);
7252 static cpumask_var_t *doms_cur; /* current sched domains */
7253 static int ndoms_cur; /* number of sched domains in 'doms_cur' */
7254 static struct sched_domain_attr *dattr_cur;
7255 /* attribues of custom domains in 'doms_cur' */
7258 * Special case: If a kmalloc of a doms_cur partition (array of
7259 * cpumask) fails, then fallback to a single sched domain,
7260 * as determined by the single cpumask fallback_doms.
7262 static cpumask_var_t fallback_doms;
7265 * arch_update_cpu_topology lets virtualized architectures update the
7266 * cpu core maps. It is supposed to return 1 if the topology changed
7267 * or 0 if it stayed the same.
7269 int __attribute__((weak)) arch_update_cpu_topology(void)
7274 cpumask_var_t *alloc_sched_domains(unsigned int ndoms)
7277 cpumask_var_t *doms;
7279 doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL);
7282 for (i = 0; i < ndoms; i++) {
7283 if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) {
7284 free_sched_domains(doms, i);
7291 void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms)
7294 for (i = 0; i < ndoms; i++)
7295 free_cpumask_var(doms[i]);
7300 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
7301 * For now this just excludes isolated cpus, but could be used to
7302 * exclude other special cases in the future.
7304 static int init_sched_domains(const struct cpumask *cpu_map)
7308 arch_update_cpu_topology();
7310 doms_cur = alloc_sched_domains(ndoms_cur);
7312 doms_cur = &fallback_doms;
7313 cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map);
7315 err = build_sched_domains(doms_cur[0], NULL);
7316 register_sched_domain_sysctl();
7322 * Detach sched domains from a group of cpus specified in cpu_map
7323 * These cpus will now be attached to the NULL domain
7325 static void detach_destroy_domains(const struct cpumask *cpu_map)
7330 for_each_cpu(i, cpu_map)
7331 cpu_attach_domain(NULL, &def_root_domain, i);
7335 /* handle null as "default" */
7336 static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
7337 struct sched_domain_attr *new, int idx_new)
7339 struct sched_domain_attr tmp;
7346 return !memcmp(cur ? (cur + idx_cur) : &tmp,
7347 new ? (new + idx_new) : &tmp,
7348 sizeof(struct sched_domain_attr));
7352 * Partition sched domains as specified by the 'ndoms_new'
7353 * cpumasks in the array doms_new[] of cpumasks. This compares
7354 * doms_new[] to the current sched domain partitioning, doms_cur[].
7355 * It destroys each deleted domain and builds each new domain.
7357 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
7358 * The masks don't intersect (don't overlap.) We should setup one
7359 * sched domain for each mask. CPUs not in any of the cpumasks will
7360 * not be load balanced. If the same cpumask appears both in the
7361 * current 'doms_cur' domains and in the new 'doms_new', we can leave
7364 * The passed in 'doms_new' should be allocated using
7365 * alloc_sched_domains. This routine takes ownership of it and will
7366 * free_sched_domains it when done with it. If the caller failed the
7367 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
7368 * and partition_sched_domains() will fallback to the single partition
7369 * 'fallback_doms', it also forces the domains to be rebuilt.
7371 * If doms_new == NULL it will be replaced with cpu_online_mask.
7372 * ndoms_new == 0 is a special case for destroying existing domains,
7373 * and it will not create the default domain.
7375 * Call with hotplug lock held
7377 void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
7378 struct sched_domain_attr *dattr_new)
7383 mutex_lock(&sched_domains_mutex);
7385 /* always unregister in case we don't destroy any domains */
7386 unregister_sched_domain_sysctl();
7388 /* Let architecture update cpu core mappings. */
7389 new_topology = arch_update_cpu_topology();
7391 n = doms_new ? ndoms_new : 0;
7393 /* Destroy deleted domains */
7394 for (i = 0; i < ndoms_cur; i++) {
7395 for (j = 0; j < n && !new_topology; j++) {
7396 if (cpumask_equal(doms_cur[i], doms_new[j])
7397 && dattrs_equal(dattr_cur, i, dattr_new, j))
7400 /* no match - a current sched domain not in new doms_new[] */
7401 detach_destroy_domains(doms_cur[i]);
7406 if (doms_new == NULL) {
7408 doms_new = &fallback_doms;
7409 cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map);
7410 WARN_ON_ONCE(dattr_new);
7413 /* Build new domains */
7414 for (i = 0; i < ndoms_new; i++) {
7415 for (j = 0; j < ndoms_cur && !new_topology; j++) {
7416 if (cpumask_equal(doms_new[i], doms_cur[j])
7417 && dattrs_equal(dattr_new, i, dattr_cur, j))
7420 /* no match - add a new doms_new */
7421 build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL);
7426 /* Remember the new sched domains */
7427 if (doms_cur != &fallback_doms)
7428 free_sched_domains(doms_cur, ndoms_cur);
7429 kfree(dattr_cur); /* kfree(NULL) is safe */
7430 doms_cur = doms_new;
7431 dattr_cur = dattr_new;
7432 ndoms_cur = ndoms_new;
7434 register_sched_domain_sysctl();
7436 mutex_unlock(&sched_domains_mutex);
7439 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
7440 static void reinit_sched_domains(void)
7444 /* Destroy domains first to force the rebuild */
7445 partition_sched_domains(0, NULL, NULL);
7447 rebuild_sched_domains();
7451 static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt)
7453 unsigned int level = 0;
7455 if (sscanf(buf, "%u", &level) != 1)
7459 * level is always be positive so don't check for
7460 * level < POWERSAVINGS_BALANCE_NONE which is 0
7461 * What happens on 0 or 1 byte write,
7462 * need to check for count as well?
7465 if (level >= MAX_POWERSAVINGS_BALANCE_LEVELS)
7469 sched_smt_power_savings = level;
7471 sched_mc_power_savings = level;
7473 reinit_sched_domains();
7478 #ifdef CONFIG_SCHED_MC
7479 static ssize_t sched_mc_power_savings_show(struct sysdev_class *class,
7480 struct sysdev_class_attribute *attr,
7483 return sprintf(page, "%u\n", sched_mc_power_savings);
7485 static ssize_t sched_mc_power_savings_store(struct sysdev_class *class,
7486 struct sysdev_class_attribute *attr,
7487 const char *buf, size_t count)
7489 return sched_power_savings_store(buf, count, 0);
7491 static SYSDEV_CLASS_ATTR(sched_mc_power_savings, 0644,
7492 sched_mc_power_savings_show,
7493 sched_mc_power_savings_store);
7496 #ifdef CONFIG_SCHED_SMT
7497 static ssize_t sched_smt_power_savings_show(struct sysdev_class *dev,
7498 struct sysdev_class_attribute *attr,
7501 return sprintf(page, "%u\n", sched_smt_power_savings);
7503 static ssize_t sched_smt_power_savings_store(struct sysdev_class *dev,
7504 struct sysdev_class_attribute *attr,
7505 const char *buf, size_t count)
7507 return sched_power_savings_store(buf, count, 1);
7509 static SYSDEV_CLASS_ATTR(sched_smt_power_savings, 0644,
7510 sched_smt_power_savings_show,
7511 sched_smt_power_savings_store);
7514 int __init sched_create_sysfs_power_savings_entries(struct sysdev_class *cls)
7518 #ifdef CONFIG_SCHED_SMT
7520 err = sysfs_create_file(&cls->kset.kobj,
7521 &attr_sched_smt_power_savings.attr);
7523 #ifdef CONFIG_SCHED_MC
7524 if (!err && mc_capable())
7525 err = sysfs_create_file(&cls->kset.kobj,
7526 &attr_sched_mc_power_savings.attr);
7530 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
7533 * Update cpusets according to cpu_active mask. If cpusets are
7534 * disabled, cpuset_update_active_cpus() becomes a simple wrapper
7535 * around partition_sched_domains().
7537 static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action,
7540 switch (action & ~CPU_TASKS_FROZEN) {
7542 case CPU_DOWN_FAILED:
7543 cpuset_update_active_cpus();
7550 static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action,
7553 switch (action & ~CPU_TASKS_FROZEN) {
7554 case CPU_DOWN_PREPARE:
7555 cpuset_update_active_cpus();
7562 static int update_runtime(struct notifier_block *nfb,
7563 unsigned long action, void *hcpu)
7565 int cpu = (int)(long)hcpu;
7568 case CPU_DOWN_PREPARE:
7569 case CPU_DOWN_PREPARE_FROZEN:
7570 disable_runtime(cpu_rq(cpu));
7573 case CPU_DOWN_FAILED:
7574 case CPU_DOWN_FAILED_FROZEN:
7576 case CPU_ONLINE_FROZEN:
7577 enable_runtime(cpu_rq(cpu));
7585 void __init sched_init_smp(void)
7587 cpumask_var_t non_isolated_cpus;
7589 alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL);
7590 alloc_cpumask_var(&fallback_doms, GFP_KERNEL);
7593 mutex_lock(&sched_domains_mutex);
7594 init_sched_domains(cpu_active_mask);
7595 cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map);
7596 if (cpumask_empty(non_isolated_cpus))
7597 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus);
7598 mutex_unlock(&sched_domains_mutex);
7601 hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE);
7602 hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE);
7604 /* RT runtime code needs to handle some hotplug events */
7605 hotcpu_notifier(update_runtime, 0);
7609 /* Move init over to a non-isolated CPU */
7610 if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0)
7612 sched_init_granularity();
7613 free_cpumask_var(non_isolated_cpus);
7615 init_sched_rt_class();
7618 void __init sched_init_smp(void)
7620 sched_init_granularity();
7622 #endif /* CONFIG_SMP */
7624 const_debug unsigned int sysctl_timer_migration = 1;
7626 int in_sched_functions(unsigned long addr)
7628 return in_lock_functions(addr) ||
7629 (addr >= (unsigned long)__sched_text_start
7630 && addr < (unsigned long)__sched_text_end);
7633 static void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq)
7635 cfs_rq->tasks_timeline = RB_ROOT;
7636 INIT_LIST_HEAD(&cfs_rq->tasks);
7637 #ifdef CONFIG_FAIR_GROUP_SCHED
7639 /* allow initial update_cfs_load() to truncate */
7641 cfs_rq->load_stamp = 1;
7644 cfs_rq->min_vruntime = (u64)(-(1LL << 20));
7647 static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
7649 struct rt_prio_array *array;
7652 array = &rt_rq->active;
7653 for (i = 0; i < MAX_RT_PRIO; i++) {
7654 INIT_LIST_HEAD(array->queue + i);
7655 __clear_bit(i, array->bitmap);
7657 /* delimiter for bitsearch: */
7658 __set_bit(MAX_RT_PRIO, array->bitmap);
7660 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
7661 rt_rq->highest_prio.curr = MAX_RT_PRIO;
7663 rt_rq->highest_prio.next = MAX_RT_PRIO;
7667 rt_rq->rt_nr_migratory = 0;
7668 rt_rq->overloaded = 0;
7669 plist_head_init_raw(&rt_rq->pushable_tasks, &rq->lock);
7673 rt_rq->rt_throttled = 0;
7674 rt_rq->rt_runtime = 0;
7675 raw_spin_lock_init(&rt_rq->rt_runtime_lock);
7677 #ifdef CONFIG_RT_GROUP_SCHED
7678 rt_rq->rt_nr_boosted = 0;
7683 #ifdef CONFIG_FAIR_GROUP_SCHED
7684 static void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
7685 struct sched_entity *se, int cpu,
7686 struct sched_entity *parent)
7688 struct rq *rq = cpu_rq(cpu);
7689 tg->cfs_rq[cpu] = cfs_rq;
7690 init_cfs_rq(cfs_rq, rq);
7694 /* se could be NULL for root_task_group */
7699 se->cfs_rq = &rq->cfs;
7701 se->cfs_rq = parent->my_q;
7704 update_load_set(&se->load, 0);
7705 se->parent = parent;
7709 #ifdef CONFIG_RT_GROUP_SCHED
7710 static void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
7711 struct sched_rt_entity *rt_se, int cpu,
7712 struct sched_rt_entity *parent)
7714 struct rq *rq = cpu_rq(cpu);
7716 tg->rt_rq[cpu] = rt_rq;
7717 init_rt_rq(rt_rq, rq);
7719 rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime;
7721 tg->rt_se[cpu] = rt_se;
7726 rt_se->rt_rq = &rq->rt;
7728 rt_se->rt_rq = parent->my_q;
7730 rt_se->my_q = rt_rq;
7731 rt_se->parent = parent;
7732 INIT_LIST_HEAD(&rt_se->run_list);
7736 void __init sched_init(void)
7739 unsigned long alloc_size = 0, ptr;
7741 #ifdef CONFIG_FAIR_GROUP_SCHED
7742 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
7744 #ifdef CONFIG_RT_GROUP_SCHED
7745 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
7747 #ifdef CONFIG_CPUMASK_OFFSTACK
7748 alloc_size += num_possible_cpus() * cpumask_size();
7751 ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT);
7753 #ifdef CONFIG_FAIR_GROUP_SCHED
7754 root_task_group.se = (struct sched_entity **)ptr;
7755 ptr += nr_cpu_ids * sizeof(void **);
7757 root_task_group.cfs_rq = (struct cfs_rq **)ptr;
7758 ptr += nr_cpu_ids * sizeof(void **);
7760 #endif /* CONFIG_FAIR_GROUP_SCHED */
7761 #ifdef CONFIG_RT_GROUP_SCHED
7762 root_task_group.rt_se = (struct sched_rt_entity **)ptr;
7763 ptr += nr_cpu_ids * sizeof(void **);
7765 root_task_group.rt_rq = (struct rt_rq **)ptr;
7766 ptr += nr_cpu_ids * sizeof(void **);
7768 #endif /* CONFIG_RT_GROUP_SCHED */
7769 #ifdef CONFIG_CPUMASK_OFFSTACK
7770 for_each_possible_cpu(i) {
7771 per_cpu(load_balance_tmpmask, i) = (void *)ptr;
7772 ptr += cpumask_size();
7774 #endif /* CONFIG_CPUMASK_OFFSTACK */
7778 init_defrootdomain();
7781 init_rt_bandwidth(&def_rt_bandwidth,
7782 global_rt_period(), global_rt_runtime());
7784 #ifdef CONFIG_RT_GROUP_SCHED
7785 init_rt_bandwidth(&root_task_group.rt_bandwidth,
7786 global_rt_period(), global_rt_runtime());
7787 #endif /* CONFIG_RT_GROUP_SCHED */
7789 #ifdef CONFIG_CGROUP_SCHED
7790 list_add(&root_task_group.list, &task_groups);
7791 INIT_LIST_HEAD(&root_task_group.children);
7792 autogroup_init(&init_task);
7793 #endif /* CONFIG_CGROUP_SCHED */
7795 for_each_possible_cpu(i) {
7799 raw_spin_lock_init(&rq->lock);
7801 rq->calc_load_active = 0;
7802 rq->calc_load_update = jiffies + LOAD_FREQ;
7803 init_cfs_rq(&rq->cfs, rq);
7804 init_rt_rq(&rq->rt, rq);
7805 #ifdef CONFIG_FAIR_GROUP_SCHED
7806 root_task_group.shares = root_task_group_load;
7807 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
7809 * How much cpu bandwidth does root_task_group get?
7811 * In case of task-groups formed thr' the cgroup filesystem, it
7812 * gets 100% of the cpu resources in the system. This overall
7813 * system cpu resource is divided among the tasks of
7814 * root_task_group and its child task-groups in a fair manner,
7815 * based on each entity's (task or task-group's) weight
7816 * (se->load.weight).
7818 * In other words, if root_task_group has 10 tasks of weight
7819 * 1024) and two child groups A0 and A1 (of weight 1024 each),
7820 * then A0's share of the cpu resource is:
7822 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
7824 * We achieve this by letting root_task_group's tasks sit
7825 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
7827 init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL);
7828 #endif /* CONFIG_FAIR_GROUP_SCHED */
7830 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime;
7831 #ifdef CONFIG_RT_GROUP_SCHED
7832 INIT_LIST_HEAD(&rq->leaf_rt_rq_list);
7833 init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL);
7836 for (j = 0; j < CPU_LOAD_IDX_MAX; j++)
7837 rq->cpu_load[j] = 0;
7839 rq->last_load_update_tick = jiffies;
7844 rq->cpu_power = SCHED_LOAD_SCALE;
7845 rq->post_schedule = 0;
7846 rq->active_balance = 0;
7847 rq->next_balance = jiffies;
7852 rq->avg_idle = 2*sysctl_sched_migration_cost;
7853 rq_attach_root(rq, &def_root_domain);
7855 rq->nohz_balance_kick = 0;
7856 init_sched_softirq_csd(&per_cpu(remote_sched_softirq_cb, i));
7860 atomic_set(&rq->nr_iowait, 0);
7863 set_load_weight(&init_task);
7865 #ifdef CONFIG_PREEMPT_NOTIFIERS
7866 INIT_HLIST_HEAD(&init_task.preempt_notifiers);
7870 open_softirq(SCHED_SOFTIRQ, run_rebalance_domains);
7873 #ifdef CONFIG_RT_MUTEXES
7874 plist_head_init_raw(&init_task.pi_waiters, &init_task.pi_lock);
7878 * The boot idle thread does lazy MMU switching as well:
7880 atomic_inc(&init_mm.mm_count);
7881 enter_lazy_tlb(&init_mm, current);
7884 * Make us the idle thread. Technically, schedule() should not be
7885 * called from this thread, however somewhere below it might be,
7886 * but because we are the idle thread, we just pick up running again
7887 * when this runqueue becomes "idle".
7889 init_idle(current, smp_processor_id());
7891 calc_load_update = jiffies + LOAD_FREQ;
7894 * During early bootup we pretend to be a normal task:
7896 current->sched_class = &fair_sched_class;
7898 /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */
7899 zalloc_cpumask_var(&nohz_cpu_mask, GFP_NOWAIT);
7901 zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT);
7903 zalloc_cpumask_var(&nohz.idle_cpus_mask, GFP_NOWAIT);
7904 alloc_cpumask_var(&nohz.grp_idle_mask, GFP_NOWAIT);
7905 atomic_set(&nohz.load_balancer, nr_cpu_ids);
7906 atomic_set(&nohz.first_pick_cpu, nr_cpu_ids);
7907 atomic_set(&nohz.second_pick_cpu, nr_cpu_ids);
7909 /* May be allocated at isolcpus cmdline parse time */
7910 if (cpu_isolated_map == NULL)
7911 zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
7914 scheduler_running = 1;
7917 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
7918 static inline int preempt_count_equals(int preempt_offset)
7920 int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth();
7922 return (nested == preempt_offset);
7925 void __might_sleep(const char *file, int line, int preempt_offset)
7928 static unsigned long prev_jiffy; /* ratelimiting */
7930 if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) ||
7931 system_state != SYSTEM_RUNNING || oops_in_progress)
7933 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
7935 prev_jiffy = jiffies;
7938 "BUG: sleeping function called from invalid context at %s:%d\n",
7941 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
7942 in_atomic(), irqs_disabled(),
7943 current->pid, current->comm);
7945 debug_show_held_locks(current);
7946 if (irqs_disabled())
7947 print_irqtrace_events(current);
7951 EXPORT_SYMBOL(__might_sleep);
7954 #ifdef CONFIG_MAGIC_SYSRQ
7955 static void normalize_task(struct rq *rq, struct task_struct *p)
7957 const struct sched_class *prev_class = p->sched_class;
7958 int old_prio = p->prio;
7961 on_rq = p->se.on_rq;
7963 deactivate_task(rq, p, 0);
7964 __setscheduler(rq, p, SCHED_NORMAL, 0);
7966 activate_task(rq, p, 0);
7967 resched_task(rq->curr);
7970 check_class_changed(rq, p, prev_class, old_prio);
7973 void normalize_rt_tasks(void)
7975 struct task_struct *g, *p;
7976 unsigned long flags;
7979 read_lock_irqsave(&tasklist_lock, flags);
7980 do_each_thread(g, p) {
7982 * Only normalize user tasks:
7987 p->se.exec_start = 0;
7988 #ifdef CONFIG_SCHEDSTATS
7989 p->se.statistics.wait_start = 0;
7990 p->se.statistics.sleep_start = 0;
7991 p->se.statistics.block_start = 0;
7996 * Renice negative nice level userspace
7999 if (TASK_NICE(p) < 0 && p->mm)
8000 set_user_nice(p, 0);
8004 raw_spin_lock(&p->pi_lock);
8005 rq = __task_rq_lock(p);
8007 normalize_task(rq, p);
8009 __task_rq_unlock(rq);
8010 raw_spin_unlock(&p->pi_lock);
8011 } while_each_thread(g, p);
8013 read_unlock_irqrestore(&tasklist_lock, flags);
8016 #endif /* CONFIG_MAGIC_SYSRQ */
8018 #if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
8020 * These functions are only useful for the IA64 MCA handling, or kdb.
8022 * They can only be called when the whole system has been
8023 * stopped - every CPU needs to be quiescent, and no scheduling
8024 * activity can take place. Using them for anything else would
8025 * be a serious bug, and as a result, they aren't even visible
8026 * under any other configuration.
8030 * curr_task - return the current task for a given cpu.
8031 * @cpu: the processor in question.
8033 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
8035 struct task_struct *curr_task(int cpu)
8037 return cpu_curr(cpu);
8040 #endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
8044 * set_curr_task - set the current task for a given cpu.
8045 * @cpu: the processor in question.
8046 * @p: the task pointer to set.
8048 * Description: This function must only be used when non-maskable interrupts
8049 * are serviced on a separate stack. It allows the architecture to switch the
8050 * notion of the current task on a cpu in a non-blocking manner. This function
8051 * must be called with all CPU's synchronized, and interrupts disabled, the
8052 * and caller must save the original value of the current task (see
8053 * curr_task() above) and restore that value before reenabling interrupts and
8054 * re-starting the system.
8056 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
8058 void set_curr_task(int cpu, struct task_struct *p)
8065 #ifdef CONFIG_FAIR_GROUP_SCHED
8066 static void free_fair_sched_group(struct task_group *tg)
8070 for_each_possible_cpu(i) {
8072 kfree(tg->cfs_rq[i]);
8082 int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
8084 struct cfs_rq *cfs_rq;
8085 struct sched_entity *se;
8088 tg->cfs_rq = kzalloc(sizeof(cfs_rq) * nr_cpu_ids, GFP_KERNEL);
8091 tg->se = kzalloc(sizeof(se) * nr_cpu_ids, GFP_KERNEL);
8095 tg->shares = NICE_0_LOAD;
8097 for_each_possible_cpu(i) {
8098 cfs_rq = kzalloc_node(sizeof(struct cfs_rq),
8099 GFP_KERNEL, cpu_to_node(i));
8103 se = kzalloc_node(sizeof(struct sched_entity),
8104 GFP_KERNEL, cpu_to_node(i));
8108 init_tg_cfs_entry(tg, cfs_rq, se, i, parent->se[i]);
8119 static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
8121 struct rq *rq = cpu_rq(cpu);
8122 unsigned long flags;
8125 * Only empty task groups can be destroyed; so we can speculatively
8126 * check on_list without danger of it being re-added.
8128 if (!tg->cfs_rq[cpu]->on_list)
8131 raw_spin_lock_irqsave(&rq->lock, flags);
8132 list_del_leaf_cfs_rq(tg->cfs_rq[cpu]);
8133 raw_spin_unlock_irqrestore(&rq->lock, flags);
8135 #else /* !CONFG_FAIR_GROUP_SCHED */
8136 static inline void free_fair_sched_group(struct task_group *tg)
8141 int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
8146 static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
8149 #endif /* CONFIG_FAIR_GROUP_SCHED */
8151 #ifdef CONFIG_RT_GROUP_SCHED
8152 static void free_rt_sched_group(struct task_group *tg)
8156 destroy_rt_bandwidth(&tg->rt_bandwidth);
8158 for_each_possible_cpu(i) {
8160 kfree(tg->rt_rq[i]);
8162 kfree(tg->rt_se[i]);
8170 int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
8172 struct rt_rq *rt_rq;
8173 struct sched_rt_entity *rt_se;
8177 tg->rt_rq = kzalloc(sizeof(rt_rq) * nr_cpu_ids, GFP_KERNEL);
8180 tg->rt_se = kzalloc(sizeof(rt_se) * nr_cpu_ids, GFP_KERNEL);
8184 init_rt_bandwidth(&tg->rt_bandwidth,
8185 ktime_to_ns(def_rt_bandwidth.rt_period), 0);
8187 for_each_possible_cpu(i) {
8190 rt_rq = kzalloc_node(sizeof(struct rt_rq),
8191 GFP_KERNEL, cpu_to_node(i));
8195 rt_se = kzalloc_node(sizeof(struct sched_rt_entity),
8196 GFP_KERNEL, cpu_to_node(i));
8200 init_tg_rt_entry(tg, rt_rq, rt_se, i, parent->rt_se[i]);
8210 #else /* !CONFIG_RT_GROUP_SCHED */
8211 static inline void free_rt_sched_group(struct task_group *tg)
8216 int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
8220 #endif /* CONFIG_RT_GROUP_SCHED */
8222 #ifdef CONFIG_CGROUP_SCHED
8223 static void free_sched_group(struct task_group *tg)
8225 free_fair_sched_group(tg);
8226 free_rt_sched_group(tg);
8231 /* allocate runqueue etc for a new task group */
8232 struct task_group *sched_create_group(struct task_group *parent)
8234 struct task_group *tg;
8235 unsigned long flags;
8237 tg = kzalloc(sizeof(*tg), GFP_KERNEL);
8239 return ERR_PTR(-ENOMEM);
8241 if (!alloc_fair_sched_group(tg, parent))
8244 if (!alloc_rt_sched_group(tg, parent))
8247 spin_lock_irqsave(&task_group_lock, flags);
8248 list_add_rcu(&tg->list, &task_groups);
8250 WARN_ON(!parent); /* root should already exist */
8252 tg->parent = parent;
8253 INIT_LIST_HEAD(&tg->children);
8254 list_add_rcu(&tg->siblings, &parent->children);
8255 spin_unlock_irqrestore(&task_group_lock, flags);
8260 free_sched_group(tg);
8261 return ERR_PTR(-ENOMEM);
8264 /* rcu callback to free various structures associated with a task group */
8265 static void free_sched_group_rcu(struct rcu_head *rhp)
8267 /* now it should be safe to free those cfs_rqs */
8268 free_sched_group(container_of(rhp, struct task_group, rcu));
8271 /* Destroy runqueue etc associated with a task group */
8272 void sched_destroy_group(struct task_group *tg)
8274 unsigned long flags;
8277 /* end participation in shares distribution */
8278 for_each_possible_cpu(i)
8279 unregister_fair_sched_group(tg, i);
8281 spin_lock_irqsave(&task_group_lock, flags);
8282 list_del_rcu(&tg->list);
8283 list_del_rcu(&tg->siblings);
8284 spin_unlock_irqrestore(&task_group_lock, flags);
8286 /* wait for possible concurrent references to cfs_rqs complete */
8287 call_rcu(&tg->rcu, free_sched_group_rcu);
8290 /* change task's runqueue when it moves between groups.
8291 * The caller of this function should have put the task in its new group
8292 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
8293 * reflect its new group.
8295 void sched_move_task(struct task_struct *tsk)
8298 unsigned long flags;
8301 rq = task_rq_lock(tsk, &flags);
8303 running = task_current(rq, tsk);
8304 on_rq = tsk->se.on_rq;
8307 dequeue_task(rq, tsk, 0);
8308 if (unlikely(running))
8309 tsk->sched_class->put_prev_task(rq, tsk);
8311 #ifdef CONFIG_FAIR_GROUP_SCHED
8312 if (tsk->sched_class->task_move_group)
8313 tsk->sched_class->task_move_group(tsk, on_rq);
8316 set_task_rq(tsk, task_cpu(tsk));
8318 if (unlikely(running))
8319 tsk->sched_class->set_curr_task(rq);
8321 enqueue_task(rq, tsk, 0);
8323 task_rq_unlock(rq, &flags);
8325 #endif /* CONFIG_CGROUP_SCHED */
8327 #ifdef CONFIG_FAIR_GROUP_SCHED
8328 static DEFINE_MUTEX(shares_mutex);
8330 int sched_group_set_shares(struct task_group *tg, unsigned long shares)
8333 unsigned long flags;
8336 * We can't change the weight of the root cgroup.
8341 if (shares < MIN_SHARES)
8342 shares = MIN_SHARES;
8343 else if (shares > MAX_SHARES)
8344 shares = MAX_SHARES;
8346 mutex_lock(&shares_mutex);
8347 if (tg->shares == shares)
8350 tg->shares = shares;
8351 for_each_possible_cpu(i) {
8352 struct rq *rq = cpu_rq(i);
8353 struct sched_entity *se;
8356 /* Propagate contribution to hierarchy */
8357 raw_spin_lock_irqsave(&rq->lock, flags);
8358 for_each_sched_entity(se)
8359 update_cfs_shares(group_cfs_rq(se));
8360 raw_spin_unlock_irqrestore(&rq->lock, flags);
8364 mutex_unlock(&shares_mutex);
8368 unsigned long sched_group_shares(struct task_group *tg)
8374 #ifdef CONFIG_RT_GROUP_SCHED
8376 * Ensure that the real time constraints are schedulable.
8378 static DEFINE_MUTEX(rt_constraints_mutex);
8380 static unsigned long to_ratio(u64 period, u64 runtime)
8382 if (runtime == RUNTIME_INF)
8385 return div64_u64(runtime << 20, period);
8388 /* Must be called with tasklist_lock held */
8389 static inline int tg_has_rt_tasks(struct task_group *tg)
8391 struct task_struct *g, *p;
8393 do_each_thread(g, p) {
8394 if (rt_task(p) && rt_rq_of_se(&p->rt)->tg == tg)
8396 } while_each_thread(g, p);
8401 struct rt_schedulable_data {
8402 struct task_group *tg;
8407 static int tg_schedulable(struct task_group *tg, void *data)
8409 struct rt_schedulable_data *d = data;
8410 struct task_group *child;
8411 unsigned long total, sum = 0;
8412 u64 period, runtime;
8414 period = ktime_to_ns(tg->rt_bandwidth.rt_period);
8415 runtime = tg->rt_bandwidth.rt_runtime;
8418 period = d->rt_period;
8419 runtime = d->rt_runtime;
8423 * Cannot have more runtime than the period.
8425 if (runtime > period && runtime != RUNTIME_INF)
8429 * Ensure we don't starve existing RT tasks.
8431 if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg))
8434 total = to_ratio(period, runtime);
8437 * Nobody can have more than the global setting allows.
8439 if (total > to_ratio(global_rt_period(), global_rt_runtime()))
8443 * The sum of our children's runtime should not exceed our own.
8445 list_for_each_entry_rcu(child, &tg->children, siblings) {
8446 period = ktime_to_ns(child->rt_bandwidth.rt_period);
8447 runtime = child->rt_bandwidth.rt_runtime;
8449 if (child == d->tg) {
8450 period = d->rt_period;
8451 runtime = d->rt_runtime;
8454 sum += to_ratio(period, runtime);
8463 static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
8465 struct rt_schedulable_data data = {
8467 .rt_period = period,
8468 .rt_runtime = runtime,
8471 return walk_tg_tree(tg_schedulable, tg_nop, &data);
8474 static int tg_set_bandwidth(struct task_group *tg,
8475 u64 rt_period, u64 rt_runtime)
8479 mutex_lock(&rt_constraints_mutex);
8480 read_lock(&tasklist_lock);
8481 err = __rt_schedulable(tg, rt_period, rt_runtime);
8485 raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock);
8486 tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period);
8487 tg->rt_bandwidth.rt_runtime = rt_runtime;
8489 for_each_possible_cpu(i) {
8490 struct rt_rq *rt_rq = tg->rt_rq[i];
8492 raw_spin_lock(&rt_rq->rt_runtime_lock);
8493 rt_rq->rt_runtime = rt_runtime;
8494 raw_spin_unlock(&rt_rq->rt_runtime_lock);
8496 raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock);
8498 read_unlock(&tasklist_lock);
8499 mutex_unlock(&rt_constraints_mutex);
8504 int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us)
8506 u64 rt_runtime, rt_period;
8508 rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period);
8509 rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC;
8510 if (rt_runtime_us < 0)
8511 rt_runtime = RUNTIME_INF;
8513 return tg_set_bandwidth(tg, rt_period, rt_runtime);
8516 long sched_group_rt_runtime(struct task_group *tg)
8520 if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF)
8523 rt_runtime_us = tg->rt_bandwidth.rt_runtime;
8524 do_div(rt_runtime_us, NSEC_PER_USEC);
8525 return rt_runtime_us;
8528 int sched_group_set_rt_period(struct task_group *tg, long rt_period_us)
8530 u64 rt_runtime, rt_period;
8532 rt_period = (u64)rt_period_us * NSEC_PER_USEC;
8533 rt_runtime = tg->rt_bandwidth.rt_runtime;
8538 return tg_set_bandwidth(tg, rt_period, rt_runtime);
8541 long sched_group_rt_period(struct task_group *tg)
8545 rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period);
8546 do_div(rt_period_us, NSEC_PER_USEC);
8547 return rt_period_us;
8550 static int sched_rt_global_constraints(void)
8552 u64 runtime, period;
8555 if (sysctl_sched_rt_period <= 0)
8558 runtime = global_rt_runtime();
8559 period = global_rt_period();
8562 * Sanity check on the sysctl variables.
8564 if (runtime > period && runtime != RUNTIME_INF)
8567 mutex_lock(&rt_constraints_mutex);
8568 read_lock(&tasklist_lock);
8569 ret = __rt_schedulable(NULL, 0, 0);
8570 read_unlock(&tasklist_lock);
8571 mutex_unlock(&rt_constraints_mutex);
8576 int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk)
8578 /* Don't accept realtime tasks when there is no way for them to run */
8579 if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0)
8585 #else /* !CONFIG_RT_GROUP_SCHED */
8586 static int sched_rt_global_constraints(void)
8588 unsigned long flags;
8591 if (sysctl_sched_rt_period <= 0)
8595 * There's always some RT tasks in the root group
8596 * -- migration, kstopmachine etc..
8598 if (sysctl_sched_rt_runtime == 0)
8601 raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
8602 for_each_possible_cpu(i) {
8603 struct rt_rq *rt_rq = &cpu_rq(i)->rt;
8605 raw_spin_lock(&rt_rq->rt_runtime_lock);
8606 rt_rq->rt_runtime = global_rt_runtime();
8607 raw_spin_unlock(&rt_rq->rt_runtime_lock);
8609 raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags);
8613 #endif /* CONFIG_RT_GROUP_SCHED */
8615 int sched_rt_handler(struct ctl_table *table, int write,
8616 void __user *buffer, size_t *lenp,
8620 int old_period, old_runtime;
8621 static DEFINE_MUTEX(mutex);
8624 old_period = sysctl_sched_rt_period;
8625 old_runtime = sysctl_sched_rt_runtime;
8627 ret = proc_dointvec(table, write, buffer, lenp, ppos);
8629 if (!ret && write) {
8630 ret = sched_rt_global_constraints();
8632 sysctl_sched_rt_period = old_period;
8633 sysctl_sched_rt_runtime = old_runtime;
8635 def_rt_bandwidth.rt_runtime = global_rt_runtime();
8636 def_rt_bandwidth.rt_period =
8637 ns_to_ktime(global_rt_period());
8640 mutex_unlock(&mutex);
8645 #ifdef CONFIG_CGROUP_SCHED
8647 /* return corresponding task_group object of a cgroup */
8648 static inline struct task_group *cgroup_tg(struct cgroup *cgrp)
8650 return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id),
8651 struct task_group, css);
8654 static struct cgroup_subsys_state *
8655 cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp)
8657 struct task_group *tg, *parent;
8659 if (!cgrp->parent) {
8660 /* This is early initialization for the top cgroup */
8661 return &root_task_group.css;
8664 parent = cgroup_tg(cgrp->parent);
8665 tg = sched_create_group(parent);
8667 return ERR_PTR(-ENOMEM);
8673 cpu_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
8675 struct task_group *tg = cgroup_tg(cgrp);
8677 sched_destroy_group(tg);
8681 cpu_cgroup_can_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
8683 #ifdef CONFIG_RT_GROUP_SCHED
8684 if (!sched_rt_can_attach(cgroup_tg(cgrp), tsk))
8687 /* We don't support RT-tasks being in separate groups */
8688 if (tsk->sched_class != &fair_sched_class)
8695 cpu_cgroup_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
8696 struct task_struct *tsk, bool threadgroup)
8698 int retval = cpu_cgroup_can_attach_task(cgrp, tsk);
8702 struct task_struct *c;
8704 list_for_each_entry_rcu(c, &tsk->thread_group, thread_group) {
8705 retval = cpu_cgroup_can_attach_task(cgrp, c);
8717 cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
8718 struct cgroup *old_cont, struct task_struct *tsk,
8721 sched_move_task(tsk);
8723 struct task_struct *c;
8725 list_for_each_entry_rcu(c, &tsk->thread_group, thread_group) {
8733 cpu_cgroup_exit(struct cgroup_subsys *ss, struct cgroup *cgrp,
8734 struct cgroup *old_cgrp, struct task_struct *task)
8737 * cgroup_exit() is called in the copy_process() failure path.
8738 * Ignore this case since the task hasn't ran yet, this avoids
8739 * trying to poke a half freed task state from generic code.
8741 if (!(task->flags & PF_EXITING))
8744 sched_move_task(task);
8747 #ifdef CONFIG_FAIR_GROUP_SCHED
8748 static int cpu_shares_write_u64(struct cgroup *cgrp, struct cftype *cftype,
8751 return sched_group_set_shares(cgroup_tg(cgrp), shareval);
8754 static u64 cpu_shares_read_u64(struct cgroup *cgrp, struct cftype *cft)
8756 struct task_group *tg = cgroup_tg(cgrp);
8758 return (u64) tg->shares;
8760 #endif /* CONFIG_FAIR_GROUP_SCHED */
8762 #ifdef CONFIG_RT_GROUP_SCHED
8763 static int cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft,
8766 return sched_group_set_rt_runtime(cgroup_tg(cgrp), val);
8769 static s64 cpu_rt_runtime_read(struct cgroup *cgrp, struct cftype *cft)
8771 return sched_group_rt_runtime(cgroup_tg(cgrp));
8774 static int cpu_rt_period_write_uint(struct cgroup *cgrp, struct cftype *cftype,
8777 return sched_group_set_rt_period(cgroup_tg(cgrp), rt_period_us);
8780 static u64 cpu_rt_period_read_uint(struct cgroup *cgrp, struct cftype *cft)
8782 return sched_group_rt_period(cgroup_tg(cgrp));
8784 #endif /* CONFIG_RT_GROUP_SCHED */
8786 static struct cftype cpu_files[] = {
8787 #ifdef CONFIG_FAIR_GROUP_SCHED
8790 .read_u64 = cpu_shares_read_u64,
8791 .write_u64 = cpu_shares_write_u64,
8794 #ifdef CONFIG_RT_GROUP_SCHED
8796 .name = "rt_runtime_us",
8797 .read_s64 = cpu_rt_runtime_read,
8798 .write_s64 = cpu_rt_runtime_write,
8801 .name = "rt_period_us",
8802 .read_u64 = cpu_rt_period_read_uint,
8803 .write_u64 = cpu_rt_period_write_uint,
8808 static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont)
8810 return cgroup_add_files(cont, ss, cpu_files, ARRAY_SIZE(cpu_files));
8813 struct cgroup_subsys cpu_cgroup_subsys = {
8815 .create = cpu_cgroup_create,
8816 .destroy = cpu_cgroup_destroy,
8817 .can_attach = cpu_cgroup_can_attach,
8818 .attach = cpu_cgroup_attach,
8819 .exit = cpu_cgroup_exit,
8820 .populate = cpu_cgroup_populate,
8821 .subsys_id = cpu_cgroup_subsys_id,
8825 #endif /* CONFIG_CGROUP_SCHED */
8827 #ifdef CONFIG_CGROUP_CPUACCT
8830 * CPU accounting code for task groups.
8832 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
8833 * (balbir@in.ibm.com).
8836 /* track cpu usage of a group of tasks and its child groups */
8838 struct cgroup_subsys_state css;
8839 /* cpuusage holds pointer to a u64-type object on every cpu */
8840 u64 __percpu *cpuusage;
8841 struct percpu_counter cpustat[CPUACCT_STAT_NSTATS];
8842 struct cpuacct *parent;
8845 struct cgroup_subsys cpuacct_subsys;
8847 /* return cpu accounting group corresponding to this container */
8848 static inline struct cpuacct *cgroup_ca(struct cgroup *cgrp)
8850 return container_of(cgroup_subsys_state(cgrp, cpuacct_subsys_id),
8851 struct cpuacct, css);
8854 /* return cpu accounting group to which this task belongs */
8855 static inline struct cpuacct *task_ca(struct task_struct *tsk)
8857 return container_of(task_subsys_state(tsk, cpuacct_subsys_id),
8858 struct cpuacct, css);
8861 /* create a new cpu accounting group */
8862 static struct cgroup_subsys_state *cpuacct_create(
8863 struct cgroup_subsys *ss, struct cgroup *cgrp)
8865 struct cpuacct *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
8871 ca->cpuusage = alloc_percpu(u64);
8875 for (i = 0; i < CPUACCT_STAT_NSTATS; i++)
8876 if (percpu_counter_init(&ca->cpustat[i], 0))
8877 goto out_free_counters;
8880 ca->parent = cgroup_ca(cgrp->parent);
8886 percpu_counter_destroy(&ca->cpustat[i]);
8887 free_percpu(ca->cpuusage);
8891 return ERR_PTR(-ENOMEM);
8894 /* destroy an existing cpu accounting group */
8896 cpuacct_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
8898 struct cpuacct *ca = cgroup_ca(cgrp);
8901 for (i = 0; i < CPUACCT_STAT_NSTATS; i++)
8902 percpu_counter_destroy(&ca->cpustat[i]);
8903 free_percpu(ca->cpuusage);
8907 static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu)
8909 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
8912 #ifndef CONFIG_64BIT
8914 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
8916 raw_spin_lock_irq(&cpu_rq(cpu)->lock);
8918 raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
8926 static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val)
8928 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
8930 #ifndef CONFIG_64BIT
8932 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
8934 raw_spin_lock_irq(&cpu_rq(cpu)->lock);
8936 raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
8942 /* return total cpu usage (in nanoseconds) of a group */
8943 static u64 cpuusage_read(struct cgroup *cgrp, struct cftype *cft)
8945 struct cpuacct *ca = cgroup_ca(cgrp);
8946 u64 totalcpuusage = 0;
8949 for_each_present_cpu(i)
8950 totalcpuusage += cpuacct_cpuusage_read(ca, i);
8952 return totalcpuusage;
8955 static int cpuusage_write(struct cgroup *cgrp, struct cftype *cftype,
8958 struct cpuacct *ca = cgroup_ca(cgrp);
8967 for_each_present_cpu(i)
8968 cpuacct_cpuusage_write(ca, i, 0);
8974 static int cpuacct_percpu_seq_read(struct cgroup *cgroup, struct cftype *cft,
8977 struct cpuacct *ca = cgroup_ca(cgroup);
8981 for_each_present_cpu(i) {
8982 percpu = cpuacct_cpuusage_read(ca, i);
8983 seq_printf(m, "%llu ", (unsigned long long) percpu);
8985 seq_printf(m, "\n");
8989 static const char *cpuacct_stat_desc[] = {
8990 [CPUACCT_STAT_USER] = "user",
8991 [CPUACCT_STAT_SYSTEM] = "system",
8994 static int cpuacct_stats_show(struct cgroup *cgrp, struct cftype *cft,
8995 struct cgroup_map_cb *cb)
8997 struct cpuacct *ca = cgroup_ca(cgrp);
9000 for (i = 0; i < CPUACCT_STAT_NSTATS; i++) {
9001 s64 val = percpu_counter_read(&ca->cpustat[i]);
9002 val = cputime64_to_clock_t(val);
9003 cb->fill(cb, cpuacct_stat_desc[i], val);
9008 static struct cftype files[] = {
9011 .read_u64 = cpuusage_read,
9012 .write_u64 = cpuusage_write,
9015 .name = "usage_percpu",
9016 .read_seq_string = cpuacct_percpu_seq_read,
9020 .read_map = cpuacct_stats_show,
9024 static int cpuacct_populate(struct cgroup_subsys *ss, struct cgroup *cgrp)
9026 return cgroup_add_files(cgrp, ss, files, ARRAY_SIZE(files));
9030 * charge this task's execution time to its accounting group.
9032 * called with rq->lock held.
9034 static void cpuacct_charge(struct task_struct *tsk, u64 cputime)
9039 if (unlikely(!cpuacct_subsys.active))
9042 cpu = task_cpu(tsk);
9048 for (; ca; ca = ca->parent) {
9049 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
9050 *cpuusage += cputime;
9057 * When CONFIG_VIRT_CPU_ACCOUNTING is enabled one jiffy can be very large
9058 * in cputime_t units. As a result, cpuacct_update_stats calls
9059 * percpu_counter_add with values large enough to always overflow the
9060 * per cpu batch limit causing bad SMP scalability.
9062 * To fix this we scale percpu_counter_batch by cputime_one_jiffy so we
9063 * batch the same amount of time with CONFIG_VIRT_CPU_ACCOUNTING disabled
9064 * and enabled. We cap it at INT_MAX which is the largest allowed batch value.
9067 #define CPUACCT_BATCH \
9068 min_t(long, percpu_counter_batch * cputime_one_jiffy, INT_MAX)
9070 #define CPUACCT_BATCH 0
9074 * Charge the system/user time to the task's accounting group.
9076 static void cpuacct_update_stats(struct task_struct *tsk,
9077 enum cpuacct_stat_index idx, cputime_t val)
9080 int batch = CPUACCT_BATCH;
9082 if (unlikely(!cpuacct_subsys.active))
9089 __percpu_counter_add(&ca->cpustat[idx], val, batch);
9095 struct cgroup_subsys cpuacct_subsys = {
9097 .create = cpuacct_create,
9098 .destroy = cpuacct_destroy,
9099 .populate = cpuacct_populate,
9100 .subsys_id = cpuacct_subsys_id,
9102 #endif /* CONFIG_CGROUP_CPUACCT */