4 * Kernel scheduler and related syscalls
6 * Copyright (C) 1991-2002 Linus Torvalds
8 * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and
9 * make semaphores SMP safe
10 * 1998-11-19 Implemented schedule_timeout() and related stuff
12 * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar:
13 * hybrid priority-list and round-robin design with
14 * an array-switch method of distributing timeslices
15 * and per-CPU runqueues. Cleanups and useful suggestions
16 * by Davide Libenzi, preemptible kernel bits by Robert Love.
17 * 2003-09-03 Interactivity tuning by Con Kolivas.
18 * 2004-04-02 Scheduler domains code by Nick Piggin
19 * 2007-04-15 Work begun on replacing all interactivity tuning with a
20 * fair scheduling design by Con Kolivas.
21 * 2007-05-05 Load balancing (smp-nice) and other improvements
23 * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith
24 * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri
25 * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins,
26 * Thomas Gleixner, Mike Kravetz
30 #include <linux/module.h>
31 #include <linux/nmi.h>
32 #include <linux/init.h>
33 #include <linux/uaccess.h>
34 #include <linux/highmem.h>
35 #include <linux/smp_lock.h>
36 #include <asm/mmu_context.h>
37 #include <linux/interrupt.h>
38 #include <linux/capability.h>
39 #include <linux/completion.h>
40 #include <linux/kernel_stat.h>
41 #include <linux/debug_locks.h>
42 #include <linux/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/kthread.h>
58 #include <linux/proc_fs.h>
59 #include <linux/seq_file.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/reciprocal_div.h>
67 #include <linux/unistd.h>
68 #include <linux/pagemap.h>
69 #include <linux/hrtimer.h>
70 #include <linux/tick.h>
71 #include <linux/bootmem.h>
72 #include <linux/debugfs.h>
73 #include <linux/ctype.h>
74 #include <linux/ftrace.h>
75 #include <trace/sched.h>
78 #include <asm/irq_regs.h>
80 #include "sched_cpupri.h"
83 * Convert user-nice values [ -20 ... 0 ... 19 ]
84 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
87 #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
88 #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
89 #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
92 * 'User priority' is the nice value converted to something we
93 * can work with better when scaling various scheduler parameters,
94 * it's a [ 0 ... 39 ] range.
96 #define USER_PRIO(p) ((p)-MAX_RT_PRIO)
97 #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
98 #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
101 * Helpers for converting nanosecond timing to jiffy resolution
103 #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
105 #define NICE_0_LOAD SCHED_LOAD_SCALE
106 #define NICE_0_SHIFT SCHED_LOAD_SHIFT
109 * These are the 'tuning knobs' of the scheduler:
111 * default timeslice is 100 msecs (used only for SCHED_RR tasks).
112 * Timeslices get refilled after they expire.
114 #define DEF_TIMESLICE (100 * HZ / 1000)
117 * single value that denotes runtime == period, ie unlimited time.
119 #define RUNTIME_INF ((u64)~0ULL)
121 DEFINE_TRACE(sched_wait_task);
122 DEFINE_TRACE(sched_wakeup);
123 DEFINE_TRACE(sched_wakeup_new);
124 DEFINE_TRACE(sched_switch);
125 DEFINE_TRACE(sched_migrate_task);
129 * Divide a load by a sched group cpu_power : (load / sg->__cpu_power)
130 * Since cpu_power is a 'constant', we can use a reciprocal divide.
132 static inline u32 sg_div_cpu_power(const struct sched_group *sg, u32 load)
134 return reciprocal_divide(load, sg->reciprocal_cpu_power);
138 * Each time a sched group cpu_power is changed,
139 * we must compute its reciprocal value
141 static inline void sg_inc_cpu_power(struct sched_group *sg, u32 val)
143 sg->__cpu_power += val;
144 sg->reciprocal_cpu_power = reciprocal_value(sg->__cpu_power);
148 static inline int rt_policy(int policy)
150 if (unlikely(policy == SCHED_FIFO || policy == SCHED_RR))
155 static inline int task_has_rt_policy(struct task_struct *p)
157 return rt_policy(p->policy);
161 * This is the priority-queue data structure of the RT scheduling class:
163 struct rt_prio_array {
164 DECLARE_BITMAP(bitmap, MAX_RT_PRIO+1); /* include 1 bit for delimiter */
165 struct list_head queue[MAX_RT_PRIO];
168 struct rt_bandwidth {
169 /* nests inside the rq lock: */
170 spinlock_t rt_runtime_lock;
173 struct hrtimer rt_period_timer;
176 static struct rt_bandwidth def_rt_bandwidth;
178 static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun);
180 static enum hrtimer_restart sched_rt_period_timer(struct hrtimer *timer)
182 struct rt_bandwidth *rt_b =
183 container_of(timer, struct rt_bandwidth, rt_period_timer);
189 now = hrtimer_cb_get_time(timer);
190 overrun = hrtimer_forward(timer, now, rt_b->rt_period);
195 idle = do_sched_rt_period_timer(rt_b, overrun);
198 return idle ? HRTIMER_NORESTART : HRTIMER_RESTART;
202 void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime)
204 rt_b->rt_period = ns_to_ktime(period);
205 rt_b->rt_runtime = runtime;
207 spin_lock_init(&rt_b->rt_runtime_lock);
209 hrtimer_init(&rt_b->rt_period_timer,
210 CLOCK_MONOTONIC, HRTIMER_MODE_REL);
211 rt_b->rt_period_timer.function = sched_rt_period_timer;
214 static inline int rt_bandwidth_enabled(void)
216 return sysctl_sched_rt_runtime >= 0;
219 static void start_rt_bandwidth(struct rt_bandwidth *rt_b)
223 if (rt_bandwidth_enabled() && rt_b->rt_runtime == RUNTIME_INF)
226 if (hrtimer_active(&rt_b->rt_period_timer))
229 spin_lock(&rt_b->rt_runtime_lock);
231 if (hrtimer_active(&rt_b->rt_period_timer))
234 now = hrtimer_cb_get_time(&rt_b->rt_period_timer);
235 hrtimer_forward(&rt_b->rt_period_timer, now, rt_b->rt_period);
236 hrtimer_start_expires(&rt_b->rt_period_timer,
239 spin_unlock(&rt_b->rt_runtime_lock);
242 #ifdef CONFIG_RT_GROUP_SCHED
243 static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b)
245 hrtimer_cancel(&rt_b->rt_period_timer);
250 * sched_domains_mutex serializes calls to arch_init_sched_domains,
251 * detach_destroy_domains and partition_sched_domains.
253 static DEFINE_MUTEX(sched_domains_mutex);
255 #ifdef CONFIG_GROUP_SCHED
257 #include <linux/cgroup.h>
261 static LIST_HEAD(task_groups);
263 /* task group related information */
265 #ifdef CONFIG_CGROUP_SCHED
266 struct cgroup_subsys_state css;
269 #ifdef CONFIG_USER_SCHED
273 #ifdef CONFIG_FAIR_GROUP_SCHED
274 /* schedulable entities of this group on each cpu */
275 struct sched_entity **se;
276 /* runqueue "owned" by this group on each cpu */
277 struct cfs_rq **cfs_rq;
278 unsigned long shares;
281 #ifdef CONFIG_RT_GROUP_SCHED
282 struct sched_rt_entity **rt_se;
283 struct rt_rq **rt_rq;
285 struct rt_bandwidth rt_bandwidth;
289 struct list_head list;
291 struct task_group *parent;
292 struct list_head siblings;
293 struct list_head children;
296 #ifdef CONFIG_USER_SCHED
298 /* Helper function to pass uid information to create_sched_user() */
299 void set_tg_uid(struct user_struct *user)
301 user->tg->uid = user->uid;
306 * Every UID task group (including init_task_group aka UID-0) will
307 * be a child to this group.
309 struct task_group root_task_group;
311 #ifdef CONFIG_FAIR_GROUP_SCHED
312 /* Default task group's sched entity on each cpu */
313 static DEFINE_PER_CPU(struct sched_entity, init_sched_entity);
314 /* Default task group's cfs_rq on each cpu */
315 static DEFINE_PER_CPU(struct cfs_rq, init_cfs_rq) ____cacheline_aligned_in_smp;
316 #endif /* CONFIG_FAIR_GROUP_SCHED */
318 #ifdef CONFIG_RT_GROUP_SCHED
319 static DEFINE_PER_CPU(struct sched_rt_entity, init_sched_rt_entity);
320 static DEFINE_PER_CPU(struct rt_rq, init_rt_rq) ____cacheline_aligned_in_smp;
321 #endif /* CONFIG_RT_GROUP_SCHED */
322 #else /* !CONFIG_USER_SCHED */
323 #define root_task_group init_task_group
324 #endif /* CONFIG_USER_SCHED */
326 /* task_group_lock serializes add/remove of task groups and also changes to
327 * a task group's cpu shares.
329 static DEFINE_SPINLOCK(task_group_lock);
331 #ifdef CONFIG_FAIR_GROUP_SCHED
332 #ifdef CONFIG_USER_SCHED
333 # define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD)
334 #else /* !CONFIG_USER_SCHED */
335 # define INIT_TASK_GROUP_LOAD NICE_0_LOAD
336 #endif /* CONFIG_USER_SCHED */
339 * A weight of 0 or 1 can cause arithmetics problems.
340 * A weight of a cfs_rq is the sum of weights of which entities
341 * are queued on this cfs_rq, so a weight of a entity should not be
342 * too large, so as the shares value of a task group.
343 * (The default weight is 1024 - so there's no practical
344 * limitation from this.)
347 #define MAX_SHARES (1UL << 18)
349 static int init_task_group_load = INIT_TASK_GROUP_LOAD;
352 /* Default task group.
353 * Every task in system belong to this group at bootup.
355 struct task_group init_task_group;
357 /* return group to which a task belongs */
358 static inline struct task_group *task_group(struct task_struct *p)
360 struct task_group *tg;
362 #ifdef CONFIG_USER_SCHED
364 tg = __task_cred(p)->user->tg;
366 #elif defined(CONFIG_CGROUP_SCHED)
367 tg = container_of(task_subsys_state(p, cpu_cgroup_subsys_id),
368 struct task_group, css);
370 tg = &init_task_group;
375 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
376 static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
378 #ifdef CONFIG_FAIR_GROUP_SCHED
379 p->se.cfs_rq = task_group(p)->cfs_rq[cpu];
380 p->se.parent = task_group(p)->se[cpu];
383 #ifdef CONFIG_RT_GROUP_SCHED
384 p->rt.rt_rq = task_group(p)->rt_rq[cpu];
385 p->rt.parent = task_group(p)->rt_se[cpu];
391 static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { }
392 static inline struct task_group *task_group(struct task_struct *p)
397 #endif /* CONFIG_GROUP_SCHED */
399 /* CFS-related fields in a runqueue */
401 struct load_weight load;
402 unsigned long nr_running;
407 struct rb_root tasks_timeline;
408 struct rb_node *rb_leftmost;
410 struct list_head tasks;
411 struct list_head *balance_iterator;
414 * 'curr' points to currently running entity on this cfs_rq.
415 * It is set to NULL otherwise (i.e when none are currently running).
417 struct sched_entity *curr, *next, *last;
419 unsigned int nr_spread_over;
421 #ifdef CONFIG_FAIR_GROUP_SCHED
422 struct rq *rq; /* cpu runqueue to which this cfs_rq is attached */
425 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
426 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
427 * (like users, containers etc.)
429 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
430 * list is used during load balance.
432 struct list_head leaf_cfs_rq_list;
433 struct task_group *tg; /* group that "owns" this runqueue */
437 * the part of load.weight contributed by tasks
439 unsigned long task_weight;
442 * h_load = weight * f(tg)
444 * Where f(tg) is the recursive weight fraction assigned to
447 unsigned long h_load;
450 * this cpu's part of tg->shares
452 unsigned long shares;
455 * load.weight at the time we set shares
457 unsigned long rq_weight;
462 /* Real-Time classes' related field in a runqueue: */
464 struct rt_prio_array active;
465 unsigned long rt_nr_running;
466 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
467 int highest_prio; /* highest queued rt task prio */
470 unsigned long rt_nr_migratory;
476 /* Nests inside the rq lock: */
477 spinlock_t rt_runtime_lock;
479 #ifdef CONFIG_RT_GROUP_SCHED
480 unsigned long rt_nr_boosted;
483 struct list_head leaf_rt_rq_list;
484 struct task_group *tg;
485 struct sched_rt_entity *rt_se;
492 * We add the notion of a root-domain which will be used to define per-domain
493 * variables. Each exclusive cpuset essentially defines an island domain by
494 * fully partitioning the member cpus from any other cpuset. Whenever a new
495 * exclusive cpuset is created, we also create and attach a new root-domain
505 * The "RT overload" flag: it gets set if a CPU has more than
506 * one runnable RT task.
511 struct cpupri cpupri;
516 * By default the system creates a single root-domain with all cpus as
517 * members (mimicking the global state we have today).
519 static struct root_domain def_root_domain;
524 * This is the main, per-CPU runqueue data structure.
526 * Locking rule: those places that want to lock multiple runqueues
527 * (such as the load balancing or the thread migration code), lock
528 * acquire operations must be ordered by ascending &runqueue.
535 * nr_running and cpu_load should be in the same cacheline because
536 * remote CPUs use both these fields when doing load calculation.
538 unsigned long nr_running;
539 #define CPU_LOAD_IDX_MAX 5
540 unsigned long cpu_load[CPU_LOAD_IDX_MAX];
541 unsigned char idle_at_tick;
543 unsigned long last_tick_seen;
544 unsigned char in_nohz_recently;
546 /* capture load from *all* tasks on this cpu: */
547 struct load_weight load;
548 unsigned long nr_load_updates;
554 #ifdef CONFIG_FAIR_GROUP_SCHED
555 /* list of leaf cfs_rq on this cpu: */
556 struct list_head leaf_cfs_rq_list;
558 #ifdef CONFIG_RT_GROUP_SCHED
559 struct list_head leaf_rt_rq_list;
563 * This is part of a global counter where only the total sum
564 * over all CPUs matters. A task can increase this counter on
565 * one CPU and if it got migrated afterwards it may decrease
566 * it on another CPU. Always updated under the runqueue lock:
568 unsigned long nr_uninterruptible;
570 struct task_struct *curr, *idle;
571 unsigned long next_balance;
572 struct mm_struct *prev_mm;
579 struct root_domain *rd;
580 struct sched_domain *sd;
582 /* For active balancing */
585 /* cpu of this runqueue: */
589 unsigned long avg_load_per_task;
591 struct task_struct *migration_thread;
592 struct list_head migration_queue;
595 #ifdef CONFIG_SCHED_HRTICK
597 int hrtick_csd_pending;
598 struct call_single_data hrtick_csd;
600 struct hrtimer hrtick_timer;
603 #ifdef CONFIG_SCHEDSTATS
605 struct sched_info rq_sched_info;
606 unsigned long long rq_cpu_time;
607 /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
609 /* sys_sched_yield() stats */
610 unsigned int yld_exp_empty;
611 unsigned int yld_act_empty;
612 unsigned int yld_both_empty;
613 unsigned int yld_count;
615 /* schedule() stats */
616 unsigned int sched_switch;
617 unsigned int sched_count;
618 unsigned int sched_goidle;
620 /* try_to_wake_up() stats */
621 unsigned int ttwu_count;
622 unsigned int ttwu_local;
625 unsigned int bkl_count;
629 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
631 static inline void check_preempt_curr(struct rq *rq, struct task_struct *p, int sync)
633 rq->curr->sched_class->check_preempt_curr(rq, p, sync);
636 static inline int cpu_of(struct rq *rq)
646 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
647 * See detach_destroy_domains: synchronize_sched for details.
649 * The domain tree of any CPU may only be accessed from within
650 * preempt-disabled sections.
652 #define for_each_domain(cpu, __sd) \
653 for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
655 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
656 #define this_rq() (&__get_cpu_var(runqueues))
657 #define task_rq(p) cpu_rq(task_cpu(p))
658 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
660 static inline void update_rq_clock(struct rq *rq)
662 rq->clock = sched_clock_cpu(cpu_of(rq));
666 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
668 #ifdef CONFIG_SCHED_DEBUG
669 # define const_debug __read_mostly
671 # define const_debug static const
677 * Returns true if the current cpu runqueue is locked.
678 * This interface allows printk to be called with the runqueue lock
679 * held and know whether or not it is OK to wake up the klogd.
681 int runqueue_is_locked(void)
684 struct rq *rq = cpu_rq(cpu);
687 ret = spin_is_locked(&rq->lock);
693 * Debugging: various feature bits
696 #define SCHED_FEAT(name, enabled) \
697 __SCHED_FEAT_##name ,
700 #include "sched_features.h"
705 #define SCHED_FEAT(name, enabled) \
706 (1UL << __SCHED_FEAT_##name) * enabled |
708 const_debug unsigned int sysctl_sched_features =
709 #include "sched_features.h"
714 #ifdef CONFIG_SCHED_DEBUG
715 #define SCHED_FEAT(name, enabled) \
718 static __read_mostly char *sched_feat_names[] = {
719 #include "sched_features.h"
725 static int sched_feat_show(struct seq_file *m, void *v)
729 for (i = 0; sched_feat_names[i]; i++) {
730 if (!(sysctl_sched_features & (1UL << i)))
732 seq_printf(m, "%s ", sched_feat_names[i]);
740 sched_feat_write(struct file *filp, const char __user *ubuf,
741 size_t cnt, loff_t *ppos)
751 if (copy_from_user(&buf, ubuf, cnt))
756 if (strncmp(buf, "NO_", 3) == 0) {
761 for (i = 0; sched_feat_names[i]; i++) {
762 int len = strlen(sched_feat_names[i]);
764 if (strncmp(cmp, sched_feat_names[i], len) == 0) {
766 sysctl_sched_features &= ~(1UL << i);
768 sysctl_sched_features |= (1UL << i);
773 if (!sched_feat_names[i])
781 static int sched_feat_open(struct inode *inode, struct file *filp)
783 return single_open(filp, sched_feat_show, NULL);
786 static struct file_operations sched_feat_fops = {
787 .open = sched_feat_open,
788 .write = sched_feat_write,
791 .release = single_release,
794 static __init int sched_init_debug(void)
796 debugfs_create_file("sched_features", 0644, NULL, NULL,
801 late_initcall(sched_init_debug);
805 #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
808 * Number of tasks to iterate in a single balance run.
809 * Limited because this is done with IRQs disabled.
811 const_debug unsigned int sysctl_sched_nr_migrate = 32;
814 * ratelimit for updating the group shares.
817 unsigned int sysctl_sched_shares_ratelimit = 250000;
820 * Inject some fuzzyness into changing the per-cpu group shares
821 * this avoids remote rq-locks at the expense of fairness.
824 unsigned int sysctl_sched_shares_thresh = 4;
827 * period over which we measure -rt task cpu usage in us.
830 unsigned int sysctl_sched_rt_period = 1000000;
832 static __read_mostly int scheduler_running;
835 * part of the period that we allow rt tasks to run in us.
838 int sysctl_sched_rt_runtime = 950000;
840 static inline u64 global_rt_period(void)
842 return (u64)sysctl_sched_rt_period * NSEC_PER_USEC;
845 static inline u64 global_rt_runtime(void)
847 if (sysctl_sched_rt_runtime < 0)
850 return (u64)sysctl_sched_rt_runtime * NSEC_PER_USEC;
853 #ifndef prepare_arch_switch
854 # define prepare_arch_switch(next) do { } while (0)
856 #ifndef finish_arch_switch
857 # define finish_arch_switch(prev) do { } while (0)
860 static inline int task_current(struct rq *rq, struct task_struct *p)
862 return rq->curr == p;
865 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
866 static inline int task_running(struct rq *rq, struct task_struct *p)
868 return task_current(rq, p);
871 static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
875 static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
877 #ifdef CONFIG_DEBUG_SPINLOCK
878 /* this is a valid case when another task releases the spinlock */
879 rq->lock.owner = current;
882 * If we are tracking spinlock dependencies then we have to
883 * fix up the runqueue lock - which gets 'carried over' from
886 spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_);
888 spin_unlock_irq(&rq->lock);
891 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
892 static inline int task_running(struct rq *rq, struct task_struct *p)
897 return task_current(rq, p);
901 static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
905 * We can optimise this out completely for !SMP, because the
906 * SMP rebalancing from interrupt is the only thing that cares
911 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
912 spin_unlock_irq(&rq->lock);
914 spin_unlock(&rq->lock);
918 static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
922 * After ->oncpu is cleared, the task can be moved to a different CPU.
923 * We must ensure this doesn't happen until the switch is completely
929 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
933 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
936 * __task_rq_lock - lock the runqueue a given task resides on.
937 * Must be called interrupts disabled.
939 static inline struct rq *__task_rq_lock(struct task_struct *p)
943 struct rq *rq = task_rq(p);
944 spin_lock(&rq->lock);
945 if (likely(rq == task_rq(p)))
947 spin_unlock(&rq->lock);
952 * task_rq_lock - lock the runqueue a given task resides on and disable
953 * interrupts. Note the ordering: we can safely lookup the task_rq without
954 * explicitly disabling preemption.
956 static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags)
962 local_irq_save(*flags);
964 spin_lock(&rq->lock);
965 if (likely(rq == task_rq(p)))
967 spin_unlock_irqrestore(&rq->lock, *flags);
971 void task_rq_unlock_wait(struct task_struct *p)
973 struct rq *rq = task_rq(p);
975 smp_mb(); /* spin-unlock-wait is not a full memory barrier */
976 spin_unlock_wait(&rq->lock);
979 static void __task_rq_unlock(struct rq *rq)
982 spin_unlock(&rq->lock);
985 static inline void task_rq_unlock(struct rq *rq, unsigned long *flags)
988 spin_unlock_irqrestore(&rq->lock, *flags);
992 * this_rq_lock - lock this runqueue and disable interrupts.
994 static struct rq *this_rq_lock(void)
1001 spin_lock(&rq->lock);
1006 #ifdef CONFIG_SCHED_HRTICK
1008 * Use HR-timers to deliver accurate preemption points.
1010 * Its all a bit involved since we cannot program an hrt while holding the
1011 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
1014 * When we get rescheduled we reprogram the hrtick_timer outside of the
1020 * - enabled by features
1021 * - hrtimer is actually high res
1023 static inline int hrtick_enabled(struct rq *rq)
1025 if (!sched_feat(HRTICK))
1027 if (!cpu_active(cpu_of(rq)))
1029 return hrtimer_is_hres_active(&rq->hrtick_timer);
1032 static void hrtick_clear(struct rq *rq)
1034 if (hrtimer_active(&rq->hrtick_timer))
1035 hrtimer_cancel(&rq->hrtick_timer);
1039 * High-resolution timer tick.
1040 * Runs from hardirq context with interrupts disabled.
1042 static enum hrtimer_restart hrtick(struct hrtimer *timer)
1044 struct rq *rq = container_of(timer, struct rq, hrtick_timer);
1046 WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
1048 spin_lock(&rq->lock);
1049 update_rq_clock(rq);
1050 rq->curr->sched_class->task_tick(rq, rq->curr, 1);
1051 spin_unlock(&rq->lock);
1053 return HRTIMER_NORESTART;
1058 * called from hardirq (IPI) context
1060 static void __hrtick_start(void *arg)
1062 struct rq *rq = arg;
1064 spin_lock(&rq->lock);
1065 hrtimer_restart(&rq->hrtick_timer);
1066 rq->hrtick_csd_pending = 0;
1067 spin_unlock(&rq->lock);
1071 * Called to set the hrtick timer state.
1073 * called with rq->lock held and irqs disabled
1075 static void hrtick_start(struct rq *rq, u64 delay)
1077 struct hrtimer *timer = &rq->hrtick_timer;
1078 ktime_t time = ktime_add_ns(timer->base->get_time(), delay);
1080 hrtimer_set_expires(timer, time);
1082 if (rq == this_rq()) {
1083 hrtimer_restart(timer);
1084 } else if (!rq->hrtick_csd_pending) {
1085 __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd);
1086 rq->hrtick_csd_pending = 1;
1091 hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu)
1093 int cpu = (int)(long)hcpu;
1096 case CPU_UP_CANCELED:
1097 case CPU_UP_CANCELED_FROZEN:
1098 case CPU_DOWN_PREPARE:
1099 case CPU_DOWN_PREPARE_FROZEN:
1101 case CPU_DEAD_FROZEN:
1102 hrtick_clear(cpu_rq(cpu));
1109 static __init void init_hrtick(void)
1111 hotcpu_notifier(hotplug_hrtick, 0);
1115 * Called to set the hrtick timer state.
1117 * called with rq->lock held and irqs disabled
1119 static void hrtick_start(struct rq *rq, u64 delay)
1121 hrtimer_start(&rq->hrtick_timer, ns_to_ktime(delay), HRTIMER_MODE_REL);
1124 static inline void init_hrtick(void)
1127 #endif /* CONFIG_SMP */
1129 static void init_rq_hrtick(struct rq *rq)
1132 rq->hrtick_csd_pending = 0;
1134 rq->hrtick_csd.flags = 0;
1135 rq->hrtick_csd.func = __hrtick_start;
1136 rq->hrtick_csd.info = rq;
1139 hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1140 rq->hrtick_timer.function = hrtick;
1142 #else /* CONFIG_SCHED_HRTICK */
1143 static inline void hrtick_clear(struct rq *rq)
1147 static inline void init_rq_hrtick(struct rq *rq)
1151 static inline void init_hrtick(void)
1154 #endif /* CONFIG_SCHED_HRTICK */
1157 * resched_task - mark a task 'to be rescheduled now'.
1159 * On UP this means the setting of the need_resched flag, on SMP it
1160 * might also involve a cross-CPU call to trigger the scheduler on
1165 #ifndef tsk_is_polling
1166 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1169 static void resched_task(struct task_struct *p)
1173 assert_spin_locked(&task_rq(p)->lock);
1175 if (unlikely(test_tsk_thread_flag(p, TIF_NEED_RESCHED)))
1178 set_tsk_thread_flag(p, TIF_NEED_RESCHED);
1181 if (cpu == smp_processor_id())
1184 /* NEED_RESCHED must be visible before we test polling */
1186 if (!tsk_is_polling(p))
1187 smp_send_reschedule(cpu);
1190 static void resched_cpu(int cpu)
1192 struct rq *rq = cpu_rq(cpu);
1193 unsigned long flags;
1195 if (!spin_trylock_irqsave(&rq->lock, flags))
1197 resched_task(cpu_curr(cpu));
1198 spin_unlock_irqrestore(&rq->lock, flags);
1203 * When add_timer_on() enqueues a timer into the timer wheel of an
1204 * idle CPU then this timer might expire before the next timer event
1205 * which is scheduled to wake up that CPU. In case of a completely
1206 * idle system the next event might even be infinite time into the
1207 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1208 * leaves the inner idle loop so the newly added timer is taken into
1209 * account when the CPU goes back to idle and evaluates the timer
1210 * wheel for the next timer event.
1212 void wake_up_idle_cpu(int cpu)
1214 struct rq *rq = cpu_rq(cpu);
1216 if (cpu == smp_processor_id())
1220 * This is safe, as this function is called with the timer
1221 * wheel base lock of (cpu) held. When the CPU is on the way
1222 * to idle and has not yet set rq->curr to idle then it will
1223 * be serialized on the timer wheel base lock and take the new
1224 * timer into account automatically.
1226 if (rq->curr != rq->idle)
1230 * We can set TIF_RESCHED on the idle task of the other CPU
1231 * lockless. The worst case is that the other CPU runs the
1232 * idle task through an additional NOOP schedule()
1234 set_tsk_thread_flag(rq->idle, TIF_NEED_RESCHED);
1236 /* NEED_RESCHED must be visible before we test polling */
1238 if (!tsk_is_polling(rq->idle))
1239 smp_send_reschedule(cpu);
1241 #endif /* CONFIG_NO_HZ */
1243 #else /* !CONFIG_SMP */
1244 static void resched_task(struct task_struct *p)
1246 assert_spin_locked(&task_rq(p)->lock);
1247 set_tsk_need_resched(p);
1249 #endif /* CONFIG_SMP */
1251 #if BITS_PER_LONG == 32
1252 # define WMULT_CONST (~0UL)
1254 # define WMULT_CONST (1UL << 32)
1257 #define WMULT_SHIFT 32
1260 * Shift right and round:
1262 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1265 * delta *= weight / lw
1267 static unsigned long
1268 calc_delta_mine(unsigned long delta_exec, unsigned long weight,
1269 struct load_weight *lw)
1273 if (!lw->inv_weight) {
1274 if (BITS_PER_LONG > 32 && unlikely(lw->weight >= WMULT_CONST))
1277 lw->inv_weight = 1 + (WMULT_CONST-lw->weight/2)
1281 tmp = (u64)delta_exec * weight;
1283 * Check whether we'd overflow the 64-bit multiplication:
1285 if (unlikely(tmp > WMULT_CONST))
1286 tmp = SRR(SRR(tmp, WMULT_SHIFT/2) * lw->inv_weight,
1289 tmp = SRR(tmp * lw->inv_weight, WMULT_SHIFT);
1291 return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX);
1294 static inline void update_load_add(struct load_weight *lw, unsigned long inc)
1300 static inline void update_load_sub(struct load_weight *lw, unsigned long dec)
1307 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1308 * of tasks with abnormal "nice" values across CPUs the contribution that
1309 * each task makes to its run queue's load is weighted according to its
1310 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1311 * scaled version of the new time slice allocation that they receive on time
1315 #define WEIGHT_IDLEPRIO 2
1316 #define WMULT_IDLEPRIO (1 << 31)
1319 * Nice levels are multiplicative, with a gentle 10% change for every
1320 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1321 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1322 * that remained on nice 0.
1324 * The "10% effect" is relative and cumulative: from _any_ nice level,
1325 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1326 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1327 * If a task goes up by ~10% and another task goes down by ~10% then
1328 * the relative distance between them is ~25%.)
1330 static const int prio_to_weight[40] = {
1331 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1332 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1333 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1334 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1335 /* 0 */ 1024, 820, 655, 526, 423,
1336 /* 5 */ 335, 272, 215, 172, 137,
1337 /* 10 */ 110, 87, 70, 56, 45,
1338 /* 15 */ 36, 29, 23, 18, 15,
1342 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1344 * In cases where the weight does not change often, we can use the
1345 * precalculated inverse to speed up arithmetics by turning divisions
1346 * into multiplications:
1348 static const u32 prio_to_wmult[40] = {
1349 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1350 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1351 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1352 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1353 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1354 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1355 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1356 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1359 static void activate_task(struct rq *rq, struct task_struct *p, int wakeup);
1362 * runqueue iterator, to support SMP load-balancing between different
1363 * scheduling classes, without having to expose their internal data
1364 * structures to the load-balancing proper:
1366 struct rq_iterator {
1368 struct task_struct *(*start)(void *);
1369 struct task_struct *(*next)(void *);
1373 static unsigned long
1374 balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
1375 unsigned long max_load_move, struct sched_domain *sd,
1376 enum cpu_idle_type idle, int *all_pinned,
1377 int *this_best_prio, struct rq_iterator *iterator);
1380 iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
1381 struct sched_domain *sd, enum cpu_idle_type idle,
1382 struct rq_iterator *iterator);
1385 #ifdef CONFIG_CGROUP_CPUACCT
1386 static void cpuacct_charge(struct task_struct *tsk, u64 cputime);
1388 static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}
1391 static inline void inc_cpu_load(struct rq *rq, unsigned long load)
1393 update_load_add(&rq->load, load);
1396 static inline void dec_cpu_load(struct rq *rq, unsigned long load)
1398 update_load_sub(&rq->load, load);
1401 #if (defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)) || defined(CONFIG_RT_GROUP_SCHED)
1402 typedef int (*tg_visitor)(struct task_group *, void *);
1405 * Iterate the full tree, calling @down when first entering a node and @up when
1406 * leaving it for the final time.
1408 static int walk_tg_tree(tg_visitor down, tg_visitor up, void *data)
1410 struct task_group *parent, *child;
1414 parent = &root_task_group;
1416 ret = (*down)(parent, data);
1419 list_for_each_entry_rcu(child, &parent->children, siblings) {
1426 ret = (*up)(parent, data);
1431 parent = parent->parent;
1440 static int tg_nop(struct task_group *tg, void *data)
1447 static unsigned long source_load(int cpu, int type);
1448 static unsigned long target_load(int cpu, int type);
1449 static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd);
1451 static unsigned long cpu_avg_load_per_task(int cpu)
1453 struct rq *rq = cpu_rq(cpu);
1454 unsigned long nr_running = ACCESS_ONCE(rq->nr_running);
1457 rq->avg_load_per_task = rq->load.weight / nr_running;
1459 rq->avg_load_per_task = 0;
1461 return rq->avg_load_per_task;
1464 #ifdef CONFIG_FAIR_GROUP_SCHED
1466 static void __set_se_shares(struct sched_entity *se, unsigned long shares);
1469 * Calculate and set the cpu's group shares.
1472 update_group_shares_cpu(struct task_group *tg, int cpu,
1473 unsigned long sd_shares, unsigned long sd_rq_weight)
1475 unsigned long shares;
1476 unsigned long rq_weight;
1481 rq_weight = tg->cfs_rq[cpu]->rq_weight;
1484 * \Sum shares * rq_weight
1485 * shares = -----------------------
1489 shares = (sd_shares * rq_weight) / sd_rq_weight;
1490 shares = clamp_t(unsigned long, shares, MIN_SHARES, MAX_SHARES);
1492 if (abs(shares - tg->se[cpu]->load.weight) >
1493 sysctl_sched_shares_thresh) {
1494 struct rq *rq = cpu_rq(cpu);
1495 unsigned long flags;
1497 spin_lock_irqsave(&rq->lock, flags);
1498 tg->cfs_rq[cpu]->shares = shares;
1500 __set_se_shares(tg->se[cpu], shares);
1501 spin_unlock_irqrestore(&rq->lock, flags);
1506 * Re-compute the task group their per cpu shares over the given domain.
1507 * This needs to be done in a bottom-up fashion because the rq weight of a
1508 * parent group depends on the shares of its child groups.
1510 static int tg_shares_up(struct task_group *tg, void *data)
1512 unsigned long weight, rq_weight = 0;
1513 unsigned long shares = 0;
1514 struct sched_domain *sd = data;
1517 for_each_cpu_mask(i, sd->span) {
1519 * If there are currently no tasks on the cpu pretend there
1520 * is one of average load so that when a new task gets to
1521 * run here it will not get delayed by group starvation.
1523 weight = tg->cfs_rq[i]->load.weight;
1525 weight = NICE_0_LOAD;
1527 tg->cfs_rq[i]->rq_weight = weight;
1528 rq_weight += weight;
1529 shares += tg->cfs_rq[i]->shares;
1532 if ((!shares && rq_weight) || shares > tg->shares)
1533 shares = tg->shares;
1535 if (!sd->parent || !(sd->parent->flags & SD_LOAD_BALANCE))
1536 shares = tg->shares;
1538 for_each_cpu_mask(i, sd->span)
1539 update_group_shares_cpu(tg, i, shares, rq_weight);
1545 * Compute the cpu's hierarchical load factor for each task group.
1546 * This needs to be done in a top-down fashion because the load of a child
1547 * group is a fraction of its parents load.
1549 static int tg_load_down(struct task_group *tg, void *data)
1552 long cpu = (long)data;
1555 load = cpu_rq(cpu)->load.weight;
1557 load = tg->parent->cfs_rq[cpu]->h_load;
1558 load *= tg->cfs_rq[cpu]->shares;
1559 load /= tg->parent->cfs_rq[cpu]->load.weight + 1;
1562 tg->cfs_rq[cpu]->h_load = load;
1567 static void update_shares(struct sched_domain *sd)
1569 u64 now = cpu_clock(raw_smp_processor_id());
1570 s64 elapsed = now - sd->last_update;
1572 if (elapsed >= (s64)(u64)sysctl_sched_shares_ratelimit) {
1573 sd->last_update = now;
1574 walk_tg_tree(tg_nop, tg_shares_up, sd);
1578 static void update_shares_locked(struct rq *rq, struct sched_domain *sd)
1580 spin_unlock(&rq->lock);
1582 spin_lock(&rq->lock);
1585 static void update_h_load(long cpu)
1587 walk_tg_tree(tg_load_down, tg_nop, (void *)cpu);
1592 static inline void update_shares(struct sched_domain *sd)
1596 static inline void update_shares_locked(struct rq *rq, struct sched_domain *sd)
1603 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
1605 static int double_lock_balance(struct rq *this_rq, struct rq *busiest)
1606 __releases(this_rq->lock)
1607 __acquires(busiest->lock)
1608 __acquires(this_rq->lock)
1612 if (unlikely(!irqs_disabled())) {
1613 /* printk() doesn't work good under rq->lock */
1614 spin_unlock(&this_rq->lock);
1617 if (unlikely(!spin_trylock(&busiest->lock))) {
1618 if (busiest < this_rq) {
1619 spin_unlock(&this_rq->lock);
1620 spin_lock(&busiest->lock);
1621 spin_lock_nested(&this_rq->lock, SINGLE_DEPTH_NESTING);
1624 spin_lock_nested(&busiest->lock, SINGLE_DEPTH_NESTING);
1629 static inline void double_unlock_balance(struct rq *this_rq, struct rq *busiest)
1630 __releases(busiest->lock)
1632 spin_unlock(&busiest->lock);
1633 lock_set_subclass(&this_rq->lock.dep_map, 0, _RET_IP_);
1637 #ifdef CONFIG_FAIR_GROUP_SCHED
1638 static void cfs_rq_set_shares(struct cfs_rq *cfs_rq, unsigned long shares)
1641 cfs_rq->shares = shares;
1646 #include "sched_stats.h"
1647 #include "sched_idletask.c"
1648 #include "sched_fair.c"
1649 #include "sched_rt.c"
1650 #ifdef CONFIG_SCHED_DEBUG
1651 # include "sched_debug.c"
1654 #define sched_class_highest (&rt_sched_class)
1655 #define for_each_class(class) \
1656 for (class = sched_class_highest; class; class = class->next)
1658 static void inc_nr_running(struct rq *rq)
1663 static void dec_nr_running(struct rq *rq)
1668 static void set_load_weight(struct task_struct *p)
1670 if (task_has_rt_policy(p)) {
1671 p->se.load.weight = prio_to_weight[0] * 2;
1672 p->se.load.inv_weight = prio_to_wmult[0] >> 1;
1677 * SCHED_IDLE tasks get minimal weight:
1679 if (p->policy == SCHED_IDLE) {
1680 p->se.load.weight = WEIGHT_IDLEPRIO;
1681 p->se.load.inv_weight = WMULT_IDLEPRIO;
1685 p->se.load.weight = prio_to_weight[p->static_prio - MAX_RT_PRIO];
1686 p->se.load.inv_weight = prio_to_wmult[p->static_prio - MAX_RT_PRIO];
1689 static void update_avg(u64 *avg, u64 sample)
1691 s64 diff = sample - *avg;
1695 static void enqueue_task(struct rq *rq, struct task_struct *p, int wakeup)
1697 sched_info_queued(p);
1698 p->sched_class->enqueue_task(rq, p, wakeup);
1702 static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep)
1704 if (sleep && p->se.last_wakeup) {
1705 update_avg(&p->se.avg_overlap,
1706 p->se.sum_exec_runtime - p->se.last_wakeup);
1707 p->se.last_wakeup = 0;
1710 sched_info_dequeued(p);
1711 p->sched_class->dequeue_task(rq, p, sleep);
1716 * __normal_prio - return the priority that is based on the static prio
1718 static inline int __normal_prio(struct task_struct *p)
1720 return p->static_prio;
1724 * Calculate the expected normal priority: i.e. priority
1725 * without taking RT-inheritance into account. Might be
1726 * boosted by interactivity modifiers. Changes upon fork,
1727 * setprio syscalls, and whenever the interactivity
1728 * estimator recalculates.
1730 static inline int normal_prio(struct task_struct *p)
1734 if (task_has_rt_policy(p))
1735 prio = MAX_RT_PRIO-1 - p->rt_priority;
1737 prio = __normal_prio(p);
1742 * Calculate the current priority, i.e. the priority
1743 * taken into account by the scheduler. This value might
1744 * be boosted by RT tasks, or might be boosted by
1745 * interactivity modifiers. Will be RT if the task got
1746 * RT-boosted. If not then it returns p->normal_prio.
1748 static int effective_prio(struct task_struct *p)
1750 p->normal_prio = normal_prio(p);
1752 * If we are RT tasks or we were boosted to RT priority,
1753 * keep the priority unchanged. Otherwise, update priority
1754 * to the normal priority:
1756 if (!rt_prio(p->prio))
1757 return p->normal_prio;
1762 * activate_task - move a task to the runqueue.
1764 static void activate_task(struct rq *rq, struct task_struct *p, int wakeup)
1766 if (task_contributes_to_load(p))
1767 rq->nr_uninterruptible--;
1769 enqueue_task(rq, p, wakeup);
1774 * deactivate_task - remove a task from the runqueue.
1776 static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep)
1778 if (task_contributes_to_load(p))
1779 rq->nr_uninterruptible++;
1781 dequeue_task(rq, p, sleep);
1786 * task_curr - is this task currently executing on a CPU?
1787 * @p: the task in question.
1789 inline int task_curr(const struct task_struct *p)
1791 return cpu_curr(task_cpu(p)) == p;
1794 static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
1796 set_task_rq(p, cpu);
1799 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1800 * successfuly executed on another CPU. We must ensure that updates of
1801 * per-task data have been completed by this moment.
1804 task_thread_info(p)->cpu = cpu;
1808 static inline void check_class_changed(struct rq *rq, struct task_struct *p,
1809 const struct sched_class *prev_class,
1810 int oldprio, int running)
1812 if (prev_class != p->sched_class) {
1813 if (prev_class->switched_from)
1814 prev_class->switched_from(rq, p, running);
1815 p->sched_class->switched_to(rq, p, running);
1817 p->sched_class->prio_changed(rq, p, oldprio, running);
1822 /* Used instead of source_load when we know the type == 0 */
1823 static unsigned long weighted_cpuload(const int cpu)
1825 return cpu_rq(cpu)->load.weight;
1829 * Is this task likely cache-hot:
1832 task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
1837 * Buddy candidates are cache hot:
1839 if (sched_feat(CACHE_HOT_BUDDY) &&
1840 (&p->se == cfs_rq_of(&p->se)->next ||
1841 &p->se == cfs_rq_of(&p->se)->last))
1844 if (p->sched_class != &fair_sched_class)
1847 if (sysctl_sched_migration_cost == -1)
1849 if (sysctl_sched_migration_cost == 0)
1852 delta = now - p->se.exec_start;
1854 return delta < (s64)sysctl_sched_migration_cost;
1858 void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
1860 int old_cpu = task_cpu(p);
1861 struct rq *old_rq = cpu_rq(old_cpu), *new_rq = cpu_rq(new_cpu);
1862 struct cfs_rq *old_cfsrq = task_cfs_rq(p),
1863 *new_cfsrq = cpu_cfs_rq(old_cfsrq, new_cpu);
1866 clock_offset = old_rq->clock - new_rq->clock;
1868 trace_sched_migrate_task(p, task_cpu(p), new_cpu);
1870 #ifdef CONFIG_SCHEDSTATS
1871 if (p->se.wait_start)
1872 p->se.wait_start -= clock_offset;
1873 if (p->se.sleep_start)
1874 p->se.sleep_start -= clock_offset;
1875 if (p->se.block_start)
1876 p->se.block_start -= clock_offset;
1877 if (old_cpu != new_cpu) {
1878 schedstat_inc(p, se.nr_migrations);
1879 if (task_hot(p, old_rq->clock, NULL))
1880 schedstat_inc(p, se.nr_forced2_migrations);
1883 p->se.vruntime -= old_cfsrq->min_vruntime -
1884 new_cfsrq->min_vruntime;
1886 __set_task_cpu(p, new_cpu);
1889 struct migration_req {
1890 struct list_head list;
1892 struct task_struct *task;
1895 struct completion done;
1899 * The task's runqueue lock must be held.
1900 * Returns true if you have to wait for migration thread.
1903 migrate_task(struct task_struct *p, int dest_cpu, struct migration_req *req)
1905 struct rq *rq = task_rq(p);
1908 * If the task is not on a runqueue (and not running), then
1909 * it is sufficient to simply update the task's cpu field.
1911 if (!p->se.on_rq && !task_running(rq, p)) {
1912 set_task_cpu(p, dest_cpu);
1916 init_completion(&req->done);
1918 req->dest_cpu = dest_cpu;
1919 list_add(&req->list, &rq->migration_queue);
1925 * wait_task_inactive - wait for a thread to unschedule.
1927 * If @match_state is nonzero, it's the @p->state value just checked and
1928 * not expected to change. If it changes, i.e. @p might have woken up,
1929 * then return zero. When we succeed in waiting for @p to be off its CPU,
1930 * we return a positive number (its total switch count). If a second call
1931 * a short while later returns the same number, the caller can be sure that
1932 * @p has remained unscheduled the whole time.
1934 * The caller must ensure that the task *will* unschedule sometime soon,
1935 * else this function might spin for a *long* time. This function can't
1936 * be called with interrupts off, or it may introduce deadlock with
1937 * smp_call_function() if an IPI is sent by the same process we are
1938 * waiting to become inactive.
1940 unsigned long wait_task_inactive(struct task_struct *p, long match_state)
1942 unsigned long flags;
1949 * We do the initial early heuristics without holding
1950 * any task-queue locks at all. We'll only try to get
1951 * the runqueue lock when things look like they will
1957 * If the task is actively running on another CPU
1958 * still, just relax and busy-wait without holding
1961 * NOTE! Since we don't hold any locks, it's not
1962 * even sure that "rq" stays as the right runqueue!
1963 * But we don't care, since "task_running()" will
1964 * return false if the runqueue has changed and p
1965 * is actually now running somewhere else!
1967 while (task_running(rq, p)) {
1968 if (match_state && unlikely(p->state != match_state))
1974 * Ok, time to look more closely! We need the rq
1975 * lock now, to be *sure*. If we're wrong, we'll
1976 * just go back and repeat.
1978 rq = task_rq_lock(p, &flags);
1979 trace_sched_wait_task(rq, p);
1980 running = task_running(rq, p);
1981 on_rq = p->se.on_rq;
1983 if (!match_state || p->state == match_state)
1984 ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
1985 task_rq_unlock(rq, &flags);
1988 * If it changed from the expected state, bail out now.
1990 if (unlikely(!ncsw))
1994 * Was it really running after all now that we
1995 * checked with the proper locks actually held?
1997 * Oops. Go back and try again..
1999 if (unlikely(running)) {
2005 * It's not enough that it's not actively running,
2006 * it must be off the runqueue _entirely_, and not
2009 * So if it wa still runnable (but just not actively
2010 * running right now), it's preempted, and we should
2011 * yield - it could be a while.
2013 if (unlikely(on_rq)) {
2014 schedule_timeout_uninterruptible(1);
2019 * Ahh, all good. It wasn't running, and it wasn't
2020 * runnable, which means that it will never become
2021 * running in the future either. We're all done!
2030 * kick_process - kick a running thread to enter/exit the kernel
2031 * @p: the to-be-kicked thread
2033 * Cause a process which is running on another CPU to enter
2034 * kernel-mode, without any delay. (to get signals handled.)
2036 * NOTE: this function doesnt have to take the runqueue lock,
2037 * because all it wants to ensure is that the remote task enters
2038 * the kernel. If the IPI races and the task has been migrated
2039 * to another CPU then no harm is done and the purpose has been
2042 void kick_process(struct task_struct *p)
2048 if ((cpu != smp_processor_id()) && task_curr(p))
2049 smp_send_reschedule(cpu);
2054 * Return a low guess at the load of a migration-source cpu weighted
2055 * according to the scheduling class and "nice" value.
2057 * We want to under-estimate the load of migration sources, to
2058 * balance conservatively.
2060 static unsigned long source_load(int cpu, int type)
2062 struct rq *rq = cpu_rq(cpu);
2063 unsigned long total = weighted_cpuload(cpu);
2065 if (type == 0 || !sched_feat(LB_BIAS))
2068 return min(rq->cpu_load[type-1], total);
2072 * Return a high guess at the load of a migration-target cpu weighted
2073 * according to the scheduling class and "nice" value.
2075 static unsigned long target_load(int cpu, int type)
2077 struct rq *rq = cpu_rq(cpu);
2078 unsigned long total = weighted_cpuload(cpu);
2080 if (type == 0 || !sched_feat(LB_BIAS))
2083 return max(rq->cpu_load[type-1], total);
2087 * find_idlest_group finds and returns the least busy CPU group within the
2090 static struct sched_group *
2091 find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu)
2093 struct sched_group *idlest = NULL, *this = NULL, *group = sd->groups;
2094 unsigned long min_load = ULONG_MAX, this_load = 0;
2095 int load_idx = sd->forkexec_idx;
2096 int imbalance = 100 + (sd->imbalance_pct-100)/2;
2099 unsigned long load, avg_load;
2103 /* Skip over this group if it has no CPUs allowed */
2104 if (!cpus_intersects(group->cpumask, p->cpus_allowed))
2107 local_group = cpu_isset(this_cpu, group->cpumask);
2109 /* Tally up the load of all CPUs in the group */
2112 for_each_cpu_mask_nr(i, group->cpumask) {
2113 /* Bias balancing toward cpus of our domain */
2115 load = source_load(i, load_idx);
2117 load = target_load(i, load_idx);
2122 /* Adjust by relative CPU power of the group */
2123 avg_load = sg_div_cpu_power(group,
2124 avg_load * SCHED_LOAD_SCALE);
2127 this_load = avg_load;
2129 } else if (avg_load < min_load) {
2130 min_load = avg_load;
2133 } while (group = group->next, group != sd->groups);
2135 if (!idlest || 100*this_load < imbalance*min_load)
2141 * find_idlest_cpu - find the idlest cpu among the cpus in group.
2144 find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu,
2147 unsigned long load, min_load = ULONG_MAX;
2151 /* Traverse only the allowed CPUs */
2152 cpus_and(*tmp, group->cpumask, p->cpus_allowed);
2154 for_each_cpu_mask_nr(i, *tmp) {
2155 load = weighted_cpuload(i);
2157 if (load < min_load || (load == min_load && i == this_cpu)) {
2167 * sched_balance_self: balance the current task (running on cpu) in domains
2168 * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
2171 * Balance, ie. select the least loaded group.
2173 * Returns the target CPU number, or the same CPU if no balancing is needed.
2175 * preempt must be disabled.
2177 static int sched_balance_self(int cpu, int flag)
2179 struct task_struct *t = current;
2180 struct sched_domain *tmp, *sd = NULL;
2182 for_each_domain(cpu, tmp) {
2184 * If power savings logic is enabled for a domain, stop there.
2186 if (tmp->flags & SD_POWERSAVINGS_BALANCE)
2188 if (tmp->flags & flag)
2196 cpumask_t span, tmpmask;
2197 struct sched_group *group;
2198 int new_cpu, weight;
2200 if (!(sd->flags & flag)) {
2206 group = find_idlest_group(sd, t, cpu);
2212 new_cpu = find_idlest_cpu(group, t, cpu, &tmpmask);
2213 if (new_cpu == -1 || new_cpu == cpu) {
2214 /* Now try balancing at a lower domain level of cpu */
2219 /* Now try balancing at a lower domain level of new_cpu */
2222 weight = cpus_weight(span);
2223 for_each_domain(cpu, tmp) {
2224 if (weight <= cpus_weight(tmp->span))
2226 if (tmp->flags & flag)
2229 /* while loop will break here if sd == NULL */
2235 #endif /* CONFIG_SMP */
2238 * try_to_wake_up - wake up a thread
2239 * @p: the to-be-woken-up thread
2240 * @state: the mask of task states that can be woken
2241 * @sync: do a synchronous wakeup?
2243 * Put it on the run-queue if it's not already there. The "current"
2244 * thread is always on the run-queue (except when the actual
2245 * re-schedule is in progress), and as such you're allowed to do
2246 * the simpler "current->state = TASK_RUNNING" to mark yourself
2247 * runnable without the overhead of this.
2249 * returns failure only if the task is already active.
2251 static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync)
2253 int cpu, orig_cpu, this_cpu, success = 0;
2254 unsigned long flags;
2258 if (!sched_feat(SYNC_WAKEUPS))
2262 if (sched_feat(LB_WAKEUP_UPDATE)) {
2263 struct sched_domain *sd;
2265 this_cpu = raw_smp_processor_id();
2268 for_each_domain(this_cpu, sd) {
2269 if (cpu_isset(cpu, sd->span)) {
2278 rq = task_rq_lock(p, &flags);
2279 update_rq_clock(rq);
2280 old_state = p->state;
2281 if (!(old_state & state))
2289 this_cpu = smp_processor_id();
2292 if (unlikely(task_running(rq, p)))
2295 cpu = p->sched_class->select_task_rq(p, sync);
2296 if (cpu != orig_cpu) {
2297 set_task_cpu(p, cpu);
2298 task_rq_unlock(rq, &flags);
2299 /* might preempt at this point */
2300 rq = task_rq_lock(p, &flags);
2301 old_state = p->state;
2302 if (!(old_state & state))
2307 this_cpu = smp_processor_id();
2311 #ifdef CONFIG_SCHEDSTATS
2312 schedstat_inc(rq, ttwu_count);
2313 if (cpu == this_cpu)
2314 schedstat_inc(rq, ttwu_local);
2316 struct sched_domain *sd;
2317 for_each_domain(this_cpu, sd) {
2318 if (cpu_isset(cpu, sd->span)) {
2319 schedstat_inc(sd, ttwu_wake_remote);
2324 #endif /* CONFIG_SCHEDSTATS */
2327 #endif /* CONFIG_SMP */
2328 schedstat_inc(p, se.nr_wakeups);
2330 schedstat_inc(p, se.nr_wakeups_sync);
2331 if (orig_cpu != cpu)
2332 schedstat_inc(p, se.nr_wakeups_migrate);
2333 if (cpu == this_cpu)
2334 schedstat_inc(p, se.nr_wakeups_local);
2336 schedstat_inc(p, se.nr_wakeups_remote);
2337 activate_task(rq, p, 1);
2341 trace_sched_wakeup(rq, p, success);
2342 check_preempt_curr(rq, p, sync);
2344 p->state = TASK_RUNNING;
2346 if (p->sched_class->task_wake_up)
2347 p->sched_class->task_wake_up(rq, p);
2350 current->se.last_wakeup = current->se.sum_exec_runtime;
2352 task_rq_unlock(rq, &flags);
2357 int wake_up_process(struct task_struct *p)
2359 return try_to_wake_up(p, TASK_ALL, 0);
2361 EXPORT_SYMBOL(wake_up_process);
2363 int wake_up_state(struct task_struct *p, unsigned int state)
2365 return try_to_wake_up(p, state, 0);
2369 * Perform scheduler related setup for a newly forked process p.
2370 * p is forked by current.
2372 * __sched_fork() is basic setup used by init_idle() too:
2374 static void __sched_fork(struct task_struct *p)
2376 p->se.exec_start = 0;
2377 p->se.sum_exec_runtime = 0;
2378 p->se.prev_sum_exec_runtime = 0;
2379 p->se.last_wakeup = 0;
2380 p->se.avg_overlap = 0;
2382 #ifdef CONFIG_SCHEDSTATS
2383 p->se.wait_start = 0;
2384 p->se.sum_sleep_runtime = 0;
2385 p->se.sleep_start = 0;
2386 p->se.block_start = 0;
2387 p->se.sleep_max = 0;
2388 p->se.block_max = 0;
2390 p->se.slice_max = 0;
2394 INIT_LIST_HEAD(&p->rt.run_list);
2396 INIT_LIST_HEAD(&p->se.group_node);
2398 #ifdef CONFIG_PREEMPT_NOTIFIERS
2399 INIT_HLIST_HEAD(&p->preempt_notifiers);
2403 * We mark the process as running here, but have not actually
2404 * inserted it onto the runqueue yet. This guarantees that
2405 * nobody will actually run it, and a signal or other external
2406 * event cannot wake it up and insert it on the runqueue either.
2408 p->state = TASK_RUNNING;
2412 * fork()/clone()-time setup:
2414 void sched_fork(struct task_struct *p, int clone_flags)
2416 int cpu = get_cpu();
2421 cpu = sched_balance_self(cpu, SD_BALANCE_FORK);
2423 set_task_cpu(p, cpu);
2426 * Make sure we do not leak PI boosting priority to the child:
2428 p->prio = current->normal_prio;
2429 if (!rt_prio(p->prio))
2430 p->sched_class = &fair_sched_class;
2432 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2433 if (likely(sched_info_on()))
2434 memset(&p->sched_info, 0, sizeof(p->sched_info));
2436 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
2439 #ifdef CONFIG_PREEMPT
2440 /* Want to start with kernel preemption disabled. */
2441 task_thread_info(p)->preempt_count = 1;
2447 * wake_up_new_task - wake up a newly created task for the first time.
2449 * This function will do some initial scheduler statistics housekeeping
2450 * that must be done for every newly created context, then puts the task
2451 * on the runqueue and wakes it.
2453 void wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
2455 unsigned long flags;
2458 rq = task_rq_lock(p, &flags);
2459 BUG_ON(p->state != TASK_RUNNING);
2460 update_rq_clock(rq);
2462 p->prio = effective_prio(p);
2464 if (!p->sched_class->task_new || !current->se.on_rq) {
2465 activate_task(rq, p, 0);
2468 * Let the scheduling class do new task startup
2469 * management (if any):
2471 p->sched_class->task_new(rq, p);
2474 trace_sched_wakeup_new(rq, p, 1);
2475 check_preempt_curr(rq, p, 0);
2477 if (p->sched_class->task_wake_up)
2478 p->sched_class->task_wake_up(rq, p);
2480 task_rq_unlock(rq, &flags);
2483 #ifdef CONFIG_PREEMPT_NOTIFIERS
2486 * preempt_notifier_register - tell me when current is being being preempted & rescheduled
2487 * @notifier: notifier struct to register
2489 void preempt_notifier_register(struct preempt_notifier *notifier)
2491 hlist_add_head(¬ifier->link, ¤t->preempt_notifiers);
2493 EXPORT_SYMBOL_GPL(preempt_notifier_register);
2496 * preempt_notifier_unregister - no longer interested in preemption notifications
2497 * @notifier: notifier struct to unregister
2499 * This is safe to call from within a preemption notifier.
2501 void preempt_notifier_unregister(struct preempt_notifier *notifier)
2503 hlist_del(¬ifier->link);
2505 EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
2507 static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
2509 struct preempt_notifier *notifier;
2510 struct hlist_node *node;
2512 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
2513 notifier->ops->sched_in(notifier, raw_smp_processor_id());
2517 fire_sched_out_preempt_notifiers(struct task_struct *curr,
2518 struct task_struct *next)
2520 struct preempt_notifier *notifier;
2521 struct hlist_node *node;
2523 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
2524 notifier->ops->sched_out(notifier, next);
2527 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2529 static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
2534 fire_sched_out_preempt_notifiers(struct task_struct *curr,
2535 struct task_struct *next)
2539 #endif /* CONFIG_PREEMPT_NOTIFIERS */
2542 * prepare_task_switch - prepare to switch tasks
2543 * @rq: the runqueue preparing to switch
2544 * @prev: the current task that is being switched out
2545 * @next: the task we are going to switch to.
2547 * This is called with the rq lock held and interrupts off. It must
2548 * be paired with a subsequent finish_task_switch after the context
2551 * prepare_task_switch sets up locking and calls architecture specific
2555 prepare_task_switch(struct rq *rq, struct task_struct *prev,
2556 struct task_struct *next)
2558 fire_sched_out_preempt_notifiers(prev, next);
2559 prepare_lock_switch(rq, next);
2560 prepare_arch_switch(next);
2564 * finish_task_switch - clean up after a task-switch
2565 * @rq: runqueue associated with task-switch
2566 * @prev: the thread we just switched away from.
2568 * finish_task_switch must be called after the context switch, paired
2569 * with a prepare_task_switch call before the context switch.
2570 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2571 * and do any other architecture-specific cleanup actions.
2573 * Note that we may have delayed dropping an mm in context_switch(). If
2574 * so, we finish that here outside of the runqueue lock. (Doing it
2575 * with the lock held can cause deadlocks; see schedule() for
2578 static void finish_task_switch(struct rq *rq, struct task_struct *prev)
2579 __releases(rq->lock)
2581 struct mm_struct *mm = rq->prev_mm;
2587 * A task struct has one reference for the use as "current".
2588 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2589 * schedule one last time. The schedule call will never return, and
2590 * the scheduled task must drop that reference.
2591 * The test for TASK_DEAD must occur while the runqueue locks are
2592 * still held, otherwise prev could be scheduled on another cpu, die
2593 * there before we look at prev->state, and then the reference would
2595 * Manfred Spraul <manfred@colorfullife.com>
2597 prev_state = prev->state;
2598 finish_arch_switch(prev);
2599 finish_lock_switch(rq, prev);
2601 if (current->sched_class->post_schedule)
2602 current->sched_class->post_schedule(rq);
2605 fire_sched_in_preempt_notifiers(current);
2608 if (unlikely(prev_state == TASK_DEAD)) {
2610 * Remove function-return probe instances associated with this
2611 * task and put them back on the free list.
2613 kprobe_flush_task(prev);
2614 put_task_struct(prev);
2619 * schedule_tail - first thing a freshly forked thread must call.
2620 * @prev: the thread we just switched away from.
2622 asmlinkage void schedule_tail(struct task_struct *prev)
2623 __releases(rq->lock)
2625 struct rq *rq = this_rq();
2627 finish_task_switch(rq, prev);
2628 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2629 /* In this case, finish_task_switch does not reenable preemption */
2632 if (current->set_child_tid)
2633 put_user(task_pid_vnr(current), current->set_child_tid);
2637 * context_switch - switch to the new MM and the new
2638 * thread's register state.
2641 context_switch(struct rq *rq, struct task_struct *prev,
2642 struct task_struct *next)
2644 struct mm_struct *mm, *oldmm;
2646 prepare_task_switch(rq, prev, next);
2647 trace_sched_switch(rq, prev, next);
2649 oldmm = prev->active_mm;
2651 * For paravirt, this is coupled with an exit in switch_to to
2652 * combine the page table reload and the switch backend into
2655 arch_enter_lazy_cpu_mode();
2657 if (unlikely(!mm)) {
2658 next->active_mm = oldmm;
2659 atomic_inc(&oldmm->mm_count);
2660 enter_lazy_tlb(oldmm, next);
2662 switch_mm(oldmm, mm, next);
2664 if (unlikely(!prev->mm)) {
2665 prev->active_mm = NULL;
2666 rq->prev_mm = oldmm;
2669 * Since the runqueue lock will be released by the next
2670 * task (which is an invalid locking op but in the case
2671 * of the scheduler it's an obvious special-case), so we
2672 * do an early lockdep release here:
2674 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2675 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
2678 /* Here we just switch the register state and the stack. */
2679 switch_to(prev, next, prev);
2683 * this_rq must be evaluated again because prev may have moved
2684 * CPUs since it called schedule(), thus the 'rq' on its stack
2685 * frame will be invalid.
2687 finish_task_switch(this_rq(), prev);
2691 * nr_running, nr_uninterruptible and nr_context_switches:
2693 * externally visible scheduler statistics: current number of runnable
2694 * threads, current number of uninterruptible-sleeping threads, total
2695 * number of context switches performed since bootup.
2697 unsigned long nr_running(void)
2699 unsigned long i, sum = 0;
2701 for_each_online_cpu(i)
2702 sum += cpu_rq(i)->nr_running;
2707 unsigned long nr_uninterruptible(void)
2709 unsigned long i, sum = 0;
2711 for_each_possible_cpu(i)
2712 sum += cpu_rq(i)->nr_uninterruptible;
2715 * Since we read the counters lockless, it might be slightly
2716 * inaccurate. Do not allow it to go below zero though:
2718 if (unlikely((long)sum < 0))
2724 unsigned long long nr_context_switches(void)
2727 unsigned long long sum = 0;
2729 for_each_possible_cpu(i)
2730 sum += cpu_rq(i)->nr_switches;
2735 unsigned long nr_iowait(void)
2737 unsigned long i, sum = 0;
2739 for_each_possible_cpu(i)
2740 sum += atomic_read(&cpu_rq(i)->nr_iowait);
2745 unsigned long nr_active(void)
2747 unsigned long i, running = 0, uninterruptible = 0;
2749 for_each_online_cpu(i) {
2750 running += cpu_rq(i)->nr_running;
2751 uninterruptible += cpu_rq(i)->nr_uninterruptible;
2754 if (unlikely((long)uninterruptible < 0))
2755 uninterruptible = 0;
2757 return running + uninterruptible;
2761 * Update rq->cpu_load[] statistics. This function is usually called every
2762 * scheduler tick (TICK_NSEC).
2764 static void update_cpu_load(struct rq *this_rq)
2766 unsigned long this_load = this_rq->load.weight;
2769 this_rq->nr_load_updates++;
2771 /* Update our load: */
2772 for (i = 0, scale = 1; i < CPU_LOAD_IDX_MAX; i++, scale += scale) {
2773 unsigned long old_load, new_load;
2775 /* scale is effectively 1 << i now, and >> i divides by scale */
2777 old_load = this_rq->cpu_load[i];
2778 new_load = this_load;
2780 * Round up the averaging division if load is increasing. This
2781 * prevents us from getting stuck on 9 if the load is 10, for
2784 if (new_load > old_load)
2785 new_load += scale-1;
2786 this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) >> i;
2793 * double_rq_lock - safely lock two runqueues
2795 * Note this does not disable interrupts like task_rq_lock,
2796 * you need to do so manually before calling.
2798 static void double_rq_lock(struct rq *rq1, struct rq *rq2)
2799 __acquires(rq1->lock)
2800 __acquires(rq2->lock)
2802 BUG_ON(!irqs_disabled());
2804 spin_lock(&rq1->lock);
2805 __acquire(rq2->lock); /* Fake it out ;) */
2808 spin_lock(&rq1->lock);
2809 spin_lock_nested(&rq2->lock, SINGLE_DEPTH_NESTING);
2811 spin_lock(&rq2->lock);
2812 spin_lock_nested(&rq1->lock, SINGLE_DEPTH_NESTING);
2815 update_rq_clock(rq1);
2816 update_rq_clock(rq2);
2820 * double_rq_unlock - safely unlock two runqueues
2822 * Note this does not restore interrupts like task_rq_unlock,
2823 * you need to do so manually after calling.
2825 static void double_rq_unlock(struct rq *rq1, struct rq *rq2)
2826 __releases(rq1->lock)
2827 __releases(rq2->lock)
2829 spin_unlock(&rq1->lock);
2831 spin_unlock(&rq2->lock);
2833 __release(rq2->lock);
2837 * If dest_cpu is allowed for this process, migrate the task to it.
2838 * This is accomplished by forcing the cpu_allowed mask to only
2839 * allow dest_cpu, which will force the cpu onto dest_cpu. Then
2840 * the cpu_allowed mask is restored.
2842 static void sched_migrate_task(struct task_struct *p, int dest_cpu)
2844 struct migration_req req;
2845 unsigned long flags;
2848 rq = task_rq_lock(p, &flags);
2849 if (!cpu_isset(dest_cpu, p->cpus_allowed)
2850 || unlikely(!cpu_active(dest_cpu)))
2853 /* force the process onto the specified CPU */
2854 if (migrate_task(p, dest_cpu, &req)) {
2855 /* Need to wait for migration thread (might exit: take ref). */
2856 struct task_struct *mt = rq->migration_thread;
2858 get_task_struct(mt);
2859 task_rq_unlock(rq, &flags);
2860 wake_up_process(mt);
2861 put_task_struct(mt);
2862 wait_for_completion(&req.done);
2867 task_rq_unlock(rq, &flags);
2871 * sched_exec - execve() is a valuable balancing opportunity, because at
2872 * this point the task has the smallest effective memory and cache footprint.
2874 void sched_exec(void)
2876 int new_cpu, this_cpu = get_cpu();
2877 new_cpu = sched_balance_self(this_cpu, SD_BALANCE_EXEC);
2879 if (new_cpu != this_cpu)
2880 sched_migrate_task(current, new_cpu);
2884 * pull_task - move a task from a remote runqueue to the local runqueue.
2885 * Both runqueues must be locked.
2887 static void pull_task(struct rq *src_rq, struct task_struct *p,
2888 struct rq *this_rq, int this_cpu)
2890 deactivate_task(src_rq, p, 0);
2891 set_task_cpu(p, this_cpu);
2892 activate_task(this_rq, p, 0);
2894 * Note that idle threads have a prio of MAX_PRIO, for this test
2895 * to be always true for them.
2897 check_preempt_curr(this_rq, p, 0);
2901 * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
2904 int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu,
2905 struct sched_domain *sd, enum cpu_idle_type idle,
2909 * We do not migrate tasks that are:
2910 * 1) running (obviously), or
2911 * 2) cannot be migrated to this CPU due to cpus_allowed, or
2912 * 3) are cache-hot on their current CPU.
2914 if (!cpu_isset(this_cpu, p->cpus_allowed)) {
2915 schedstat_inc(p, se.nr_failed_migrations_affine);
2920 if (task_running(rq, p)) {
2921 schedstat_inc(p, se.nr_failed_migrations_running);
2926 * Aggressive migration if:
2927 * 1) task is cache cold, or
2928 * 2) too many balance attempts have failed.
2931 if (!task_hot(p, rq->clock, sd) ||
2932 sd->nr_balance_failed > sd->cache_nice_tries) {
2933 #ifdef CONFIG_SCHEDSTATS
2934 if (task_hot(p, rq->clock, sd)) {
2935 schedstat_inc(sd, lb_hot_gained[idle]);
2936 schedstat_inc(p, se.nr_forced_migrations);
2942 if (task_hot(p, rq->clock, sd)) {
2943 schedstat_inc(p, se.nr_failed_migrations_hot);
2949 static unsigned long
2950 balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
2951 unsigned long max_load_move, struct sched_domain *sd,
2952 enum cpu_idle_type idle, int *all_pinned,
2953 int *this_best_prio, struct rq_iterator *iterator)
2955 int loops = 0, pulled = 0, pinned = 0;
2956 struct task_struct *p;
2957 long rem_load_move = max_load_move;
2959 if (max_load_move == 0)
2965 * Start the load-balancing iterator:
2967 p = iterator->start(iterator->arg);
2969 if (!p || loops++ > sysctl_sched_nr_migrate)
2972 if ((p->se.load.weight >> 1) > rem_load_move ||
2973 !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) {
2974 p = iterator->next(iterator->arg);
2978 pull_task(busiest, p, this_rq, this_cpu);
2980 rem_load_move -= p->se.load.weight;
2983 * We only want to steal up to the prescribed amount of weighted load.
2985 if (rem_load_move > 0) {
2986 if (p->prio < *this_best_prio)
2987 *this_best_prio = p->prio;
2988 p = iterator->next(iterator->arg);
2993 * Right now, this is one of only two places pull_task() is called,
2994 * so we can safely collect pull_task() stats here rather than
2995 * inside pull_task().
2997 schedstat_add(sd, lb_gained[idle], pulled);
3000 *all_pinned = pinned;
3002 return max_load_move - rem_load_move;
3006 * move_tasks tries to move up to max_load_move weighted load from busiest to
3007 * this_rq, as part of a balancing operation within domain "sd".
3008 * Returns 1 if successful and 0 otherwise.
3010 * Called with both runqueues locked.
3012 static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
3013 unsigned long max_load_move,
3014 struct sched_domain *sd, enum cpu_idle_type idle,
3017 const struct sched_class *class = sched_class_highest;
3018 unsigned long total_load_moved = 0;
3019 int this_best_prio = this_rq->curr->prio;
3023 class->load_balance(this_rq, this_cpu, busiest,
3024 max_load_move - total_load_moved,
3025 sd, idle, all_pinned, &this_best_prio);
3026 class = class->next;
3028 if (idle == CPU_NEWLY_IDLE && this_rq->nr_running)
3031 } while (class && max_load_move > total_load_moved);
3033 return total_load_moved > 0;
3037 iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
3038 struct sched_domain *sd, enum cpu_idle_type idle,
3039 struct rq_iterator *iterator)
3041 struct task_struct *p = iterator->start(iterator->arg);
3045 if (can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) {
3046 pull_task(busiest, p, this_rq, this_cpu);
3048 * Right now, this is only the second place pull_task()
3049 * is called, so we can safely collect pull_task()
3050 * stats here rather than inside pull_task().
3052 schedstat_inc(sd, lb_gained[idle]);
3056 p = iterator->next(iterator->arg);
3063 * move_one_task tries to move exactly one task from busiest to this_rq, as
3064 * part of active balancing operations within "domain".
3065 * Returns 1 if successful and 0 otherwise.
3067 * Called with both runqueues locked.
3069 static int move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
3070 struct sched_domain *sd, enum cpu_idle_type idle)
3072 const struct sched_class *class;
3074 for (class = sched_class_highest; class; class = class->next)
3075 if (class->move_one_task(this_rq, this_cpu, busiest, sd, idle))
3082 * find_busiest_group finds and returns the busiest CPU group within the
3083 * domain. It calculates and returns the amount of weighted load which
3084 * should be moved to restore balance via the imbalance parameter.
3086 static struct sched_group *
3087 find_busiest_group(struct sched_domain *sd, int this_cpu,
3088 unsigned long *imbalance, enum cpu_idle_type idle,
3089 int *sd_idle, const cpumask_t *cpus, int *balance)
3091 struct sched_group *busiest = NULL, *this = NULL, *group = sd->groups;
3092 unsigned long max_load, avg_load, total_load, this_load, total_pwr;
3093 unsigned long max_pull;
3094 unsigned long busiest_load_per_task, busiest_nr_running;
3095 unsigned long this_load_per_task, this_nr_running;
3096 int load_idx, group_imb = 0;
3097 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3098 int power_savings_balance = 1;
3099 unsigned long leader_nr_running = 0, min_load_per_task = 0;
3100 unsigned long min_nr_running = ULONG_MAX;
3101 struct sched_group *group_min = NULL, *group_leader = NULL;
3104 max_load = this_load = total_load = total_pwr = 0;
3105 busiest_load_per_task = busiest_nr_running = 0;
3106 this_load_per_task = this_nr_running = 0;
3108 if (idle == CPU_NOT_IDLE)
3109 load_idx = sd->busy_idx;
3110 else if (idle == CPU_NEWLY_IDLE)
3111 load_idx = sd->newidle_idx;
3113 load_idx = sd->idle_idx;
3116 unsigned long load, group_capacity, max_cpu_load, min_cpu_load;
3119 int __group_imb = 0;
3120 unsigned int balance_cpu = -1, first_idle_cpu = 0;
3121 unsigned long sum_nr_running, sum_weighted_load;
3122 unsigned long sum_avg_load_per_task;
3123 unsigned long avg_load_per_task;
3125 local_group = cpu_isset(this_cpu, group->cpumask);
3128 balance_cpu = first_cpu(group->cpumask);
3130 /* Tally up the load of all CPUs in the group */
3131 sum_weighted_load = sum_nr_running = avg_load = 0;
3132 sum_avg_load_per_task = avg_load_per_task = 0;
3135 min_cpu_load = ~0UL;
3137 for_each_cpu_mask_nr(i, group->cpumask) {
3140 if (!cpu_isset(i, *cpus))
3145 if (*sd_idle && rq->nr_running)
3148 /* Bias balancing toward cpus of our domain */
3150 if (idle_cpu(i) && !first_idle_cpu) {
3155 load = target_load(i, load_idx);
3157 load = source_load(i, load_idx);
3158 if (load > max_cpu_load)
3159 max_cpu_load = load;
3160 if (min_cpu_load > load)
3161 min_cpu_load = load;
3165 sum_nr_running += rq->nr_running;
3166 sum_weighted_load += weighted_cpuload(i);
3168 sum_avg_load_per_task += cpu_avg_load_per_task(i);
3172 * First idle cpu or the first cpu(busiest) in this sched group
3173 * is eligible for doing load balancing at this and above
3174 * domains. In the newly idle case, we will allow all the cpu's
3175 * to do the newly idle load balance.
3177 if (idle != CPU_NEWLY_IDLE && local_group &&
3178 balance_cpu != this_cpu && balance) {
3183 total_load += avg_load;
3184 total_pwr += group->__cpu_power;
3186 /* Adjust by relative CPU power of the group */
3187 avg_load = sg_div_cpu_power(group,
3188 avg_load * SCHED_LOAD_SCALE);
3192 * Consider the group unbalanced when the imbalance is larger
3193 * than the average weight of two tasks.
3195 * APZ: with cgroup the avg task weight can vary wildly and
3196 * might not be a suitable number - should we keep a
3197 * normalized nr_running number somewhere that negates
3200 avg_load_per_task = sg_div_cpu_power(group,
3201 sum_avg_load_per_task * SCHED_LOAD_SCALE);
3203 if ((max_cpu_load - min_cpu_load) > 2*avg_load_per_task)
3206 group_capacity = group->__cpu_power / SCHED_LOAD_SCALE;
3209 this_load = avg_load;
3211 this_nr_running = sum_nr_running;
3212 this_load_per_task = sum_weighted_load;
3213 } else if (avg_load > max_load &&
3214 (sum_nr_running > group_capacity || __group_imb)) {
3215 max_load = avg_load;
3217 busiest_nr_running = sum_nr_running;
3218 busiest_load_per_task = sum_weighted_load;
3219 group_imb = __group_imb;
3222 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3224 * Busy processors will not participate in power savings
3227 if (idle == CPU_NOT_IDLE ||
3228 !(sd->flags & SD_POWERSAVINGS_BALANCE))
3232 * If the local group is idle or completely loaded
3233 * no need to do power savings balance at this domain
3235 if (local_group && (this_nr_running >= group_capacity ||
3237 power_savings_balance = 0;
3240 * If a group is already running at full capacity or idle,
3241 * don't include that group in power savings calculations
3243 if (!power_savings_balance || sum_nr_running >= group_capacity
3248 * Calculate the group which has the least non-idle load.
3249 * This is the group from where we need to pick up the load
3252 if ((sum_nr_running < min_nr_running) ||
3253 (sum_nr_running == min_nr_running &&
3254 first_cpu(group->cpumask) <
3255 first_cpu(group_min->cpumask))) {
3257 min_nr_running = sum_nr_running;
3258 min_load_per_task = sum_weighted_load /
3263 * Calculate the group which is almost near its
3264 * capacity but still has some space to pick up some load
3265 * from other group and save more power
3267 if (sum_nr_running <= group_capacity - 1) {
3268 if (sum_nr_running > leader_nr_running ||
3269 (sum_nr_running == leader_nr_running &&
3270 first_cpu(group->cpumask) >
3271 first_cpu(group_leader->cpumask))) {
3272 group_leader = group;
3273 leader_nr_running = sum_nr_running;
3278 group = group->next;
3279 } while (group != sd->groups);
3281 if (!busiest || this_load >= max_load || busiest_nr_running == 0)
3284 avg_load = (SCHED_LOAD_SCALE * total_load) / total_pwr;
3286 if (this_load >= avg_load ||
3287 100*max_load <= sd->imbalance_pct*this_load)
3290 busiest_load_per_task /= busiest_nr_running;
3292 busiest_load_per_task = min(busiest_load_per_task, avg_load);
3295 * We're trying to get all the cpus to the average_load, so we don't
3296 * want to push ourselves above the average load, nor do we wish to
3297 * reduce the max loaded cpu below the average load, as either of these
3298 * actions would just result in more rebalancing later, and ping-pong
3299 * tasks around. Thus we look for the minimum possible imbalance.
3300 * Negative imbalances (*we* are more loaded than anyone else) will
3301 * be counted as no imbalance for these purposes -- we can't fix that
3302 * by pulling tasks to us. Be careful of negative numbers as they'll
3303 * appear as very large values with unsigned longs.
3305 if (max_load <= busiest_load_per_task)
3309 * In the presence of smp nice balancing, certain scenarios can have
3310 * max load less than avg load(as we skip the groups at or below
3311 * its cpu_power, while calculating max_load..)
3313 if (max_load < avg_load) {
3315 goto small_imbalance;
3318 /* Don't want to pull so many tasks that a group would go idle */
3319 max_pull = min(max_load - avg_load, max_load - busiest_load_per_task);
3321 /* How much load to actually move to equalise the imbalance */
3322 *imbalance = min(max_pull * busiest->__cpu_power,
3323 (avg_load - this_load) * this->__cpu_power)
3327 * if *imbalance is less than the average load per runnable task
3328 * there is no gaurantee that any tasks will be moved so we'll have
3329 * a think about bumping its value to force at least one task to be
3332 if (*imbalance < busiest_load_per_task) {
3333 unsigned long tmp, pwr_now, pwr_move;
3337 pwr_move = pwr_now = 0;
3339 if (this_nr_running) {
3340 this_load_per_task /= this_nr_running;
3341 if (busiest_load_per_task > this_load_per_task)
3344 this_load_per_task = cpu_avg_load_per_task(this_cpu);
3346 if (max_load - this_load + busiest_load_per_task >=
3347 busiest_load_per_task * imbn) {
3348 *imbalance = busiest_load_per_task;
3353 * OK, we don't have enough imbalance to justify moving tasks,
3354 * however we may be able to increase total CPU power used by
3358 pwr_now += busiest->__cpu_power *
3359 min(busiest_load_per_task, max_load);
3360 pwr_now += this->__cpu_power *
3361 min(this_load_per_task, this_load);
3362 pwr_now /= SCHED_LOAD_SCALE;
3364 /* Amount of load we'd subtract */
3365 tmp = sg_div_cpu_power(busiest,
3366 busiest_load_per_task * SCHED_LOAD_SCALE);
3368 pwr_move += busiest->__cpu_power *
3369 min(busiest_load_per_task, max_load - tmp);
3371 /* Amount of load we'd add */
3372 if (max_load * busiest->__cpu_power <
3373 busiest_load_per_task * SCHED_LOAD_SCALE)
3374 tmp = sg_div_cpu_power(this,
3375 max_load * busiest->__cpu_power);
3377 tmp = sg_div_cpu_power(this,
3378 busiest_load_per_task * SCHED_LOAD_SCALE);
3379 pwr_move += this->__cpu_power *
3380 min(this_load_per_task, this_load + tmp);
3381 pwr_move /= SCHED_LOAD_SCALE;
3383 /* Move if we gain throughput */
3384 if (pwr_move > pwr_now)
3385 *imbalance = busiest_load_per_task;
3391 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3392 if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE))
3395 if (this == group_leader && group_leader != group_min) {
3396 *imbalance = min_load_per_task;
3406 * find_busiest_queue - find the busiest runqueue among the cpus in group.
3409 find_busiest_queue(struct sched_group *group, enum cpu_idle_type idle,
3410 unsigned long imbalance, const cpumask_t *cpus)
3412 struct rq *busiest = NULL, *rq;
3413 unsigned long max_load = 0;
3416 for_each_cpu_mask_nr(i, group->cpumask) {
3419 if (!cpu_isset(i, *cpus))
3423 wl = weighted_cpuload(i);
3425 if (rq->nr_running == 1 && wl > imbalance)
3428 if (wl > max_load) {
3438 * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
3439 * so long as it is large enough.
3441 #define MAX_PINNED_INTERVAL 512
3444 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3445 * tasks if there is an imbalance.
3447 static int load_balance(int this_cpu, struct rq *this_rq,
3448 struct sched_domain *sd, enum cpu_idle_type idle,
3449 int *balance, cpumask_t *cpus)
3451 int ld_moved, all_pinned = 0, active_balance = 0, sd_idle = 0;
3452 struct sched_group *group;
3453 unsigned long imbalance;
3455 unsigned long flags;
3460 * When power savings policy is enabled for the parent domain, idle
3461 * sibling can pick up load irrespective of busy siblings. In this case,
3462 * let the state of idle sibling percolate up as CPU_IDLE, instead of
3463 * portraying it as CPU_NOT_IDLE.
3465 if (idle != CPU_NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER &&
3466 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
3469 schedstat_inc(sd, lb_count[idle]);
3473 group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle,
3480 schedstat_inc(sd, lb_nobusyg[idle]);
3484 busiest = find_busiest_queue(group, idle, imbalance, cpus);
3486 schedstat_inc(sd, lb_nobusyq[idle]);
3490 BUG_ON(busiest == this_rq);
3492 schedstat_add(sd, lb_imbalance[idle], imbalance);
3495 if (busiest->nr_running > 1) {
3497 * Attempt to move tasks. If find_busiest_group has found
3498 * an imbalance but busiest->nr_running <= 1, the group is
3499 * still unbalanced. ld_moved simply stays zero, so it is
3500 * correctly treated as an imbalance.
3502 local_irq_save(flags);
3503 double_rq_lock(this_rq, busiest);
3504 ld_moved = move_tasks(this_rq, this_cpu, busiest,
3505 imbalance, sd, idle, &all_pinned);
3506 double_rq_unlock(this_rq, busiest);
3507 local_irq_restore(flags);
3510 * some other cpu did the load balance for us.
3512 if (ld_moved && this_cpu != smp_processor_id())
3513 resched_cpu(this_cpu);
3515 /* All tasks on this runqueue were pinned by CPU affinity */
3516 if (unlikely(all_pinned)) {
3517 cpu_clear(cpu_of(busiest), *cpus);
3518 if (!cpus_empty(*cpus))
3525 schedstat_inc(sd, lb_failed[idle]);
3526 sd->nr_balance_failed++;
3528 if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) {
3530 spin_lock_irqsave(&busiest->lock, flags);
3532 /* don't kick the migration_thread, if the curr
3533 * task on busiest cpu can't be moved to this_cpu
3535 if (!cpu_isset(this_cpu, busiest->curr->cpus_allowed)) {
3536 spin_unlock_irqrestore(&busiest->lock, flags);
3538 goto out_one_pinned;
3541 if (!busiest->active_balance) {
3542 busiest->active_balance = 1;
3543 busiest->push_cpu = this_cpu;
3546 spin_unlock_irqrestore(&busiest->lock, flags);
3548 wake_up_process(busiest->migration_thread);
3551 * We've kicked active balancing, reset the failure
3554 sd->nr_balance_failed = sd->cache_nice_tries+1;
3557 sd->nr_balance_failed = 0;
3559 if (likely(!active_balance)) {
3560 /* We were unbalanced, so reset the balancing interval */
3561 sd->balance_interval = sd->min_interval;
3564 * If we've begun active balancing, start to back off. This
3565 * case may not be covered by the all_pinned logic if there
3566 * is only 1 task on the busy runqueue (because we don't call
3569 if (sd->balance_interval < sd->max_interval)
3570 sd->balance_interval *= 2;
3573 if (!ld_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
3574 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
3580 schedstat_inc(sd, lb_balanced[idle]);
3582 sd->nr_balance_failed = 0;
3585 /* tune up the balancing interval */
3586 if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) ||
3587 (sd->balance_interval < sd->max_interval))
3588 sd->balance_interval *= 2;
3590 if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
3591 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
3602 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3603 * tasks if there is an imbalance.
3605 * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE).
3606 * this_rq is locked.
3609 load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd,
3612 struct sched_group *group;
3613 struct rq *busiest = NULL;
3614 unsigned long imbalance;
3622 * When power savings policy is enabled for the parent domain, idle
3623 * sibling can pick up load irrespective of busy siblings. In this case,
3624 * let the state of idle sibling percolate up as IDLE, instead of
3625 * portraying it as CPU_NOT_IDLE.
3627 if (sd->flags & SD_SHARE_CPUPOWER &&
3628 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
3631 schedstat_inc(sd, lb_count[CPU_NEWLY_IDLE]);
3633 update_shares_locked(this_rq, sd);
3634 group = find_busiest_group(sd, this_cpu, &imbalance, CPU_NEWLY_IDLE,
3635 &sd_idle, cpus, NULL);
3637 schedstat_inc(sd, lb_nobusyg[CPU_NEWLY_IDLE]);
3641 busiest = find_busiest_queue(group, CPU_NEWLY_IDLE, imbalance, cpus);
3643 schedstat_inc(sd, lb_nobusyq[CPU_NEWLY_IDLE]);
3647 BUG_ON(busiest == this_rq);
3649 schedstat_add(sd, lb_imbalance[CPU_NEWLY_IDLE], imbalance);
3652 if (busiest->nr_running > 1) {
3653 /* Attempt to move tasks */
3654 double_lock_balance(this_rq, busiest);
3655 /* this_rq->clock is already updated */
3656 update_rq_clock(busiest);
3657 ld_moved = move_tasks(this_rq, this_cpu, busiest,
3658 imbalance, sd, CPU_NEWLY_IDLE,
3660 double_unlock_balance(this_rq, busiest);
3662 if (unlikely(all_pinned)) {
3663 cpu_clear(cpu_of(busiest), *cpus);
3664 if (!cpus_empty(*cpus))
3670 schedstat_inc(sd, lb_failed[CPU_NEWLY_IDLE]);
3671 if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
3672 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
3675 sd->nr_balance_failed = 0;
3677 update_shares_locked(this_rq, sd);
3681 schedstat_inc(sd, lb_balanced[CPU_NEWLY_IDLE]);
3682 if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
3683 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
3685 sd->nr_balance_failed = 0;
3691 * idle_balance is called by schedule() if this_cpu is about to become
3692 * idle. Attempts to pull tasks from other CPUs.
3694 static void idle_balance(int this_cpu, struct rq *this_rq)
3696 struct sched_domain *sd;
3697 int pulled_task = 0;
3698 unsigned long next_balance = jiffies + HZ;
3701 for_each_domain(this_cpu, sd) {
3702 unsigned long interval;
3704 if (!(sd->flags & SD_LOAD_BALANCE))
3707 if (sd->flags & SD_BALANCE_NEWIDLE)
3708 /* If we've pulled tasks over stop searching: */
3709 pulled_task = load_balance_newidle(this_cpu, this_rq,
3712 interval = msecs_to_jiffies(sd->balance_interval);
3713 if (time_after(next_balance, sd->last_balance + interval))
3714 next_balance = sd->last_balance + interval;
3718 if (pulled_task || time_after(jiffies, this_rq->next_balance)) {
3720 * We are going idle. next_balance may be set based on
3721 * a busy processor. So reset next_balance.
3723 this_rq->next_balance = next_balance;
3728 * active_load_balance is run by migration threads. It pushes running tasks
3729 * off the busiest CPU onto idle CPUs. It requires at least 1 task to be
3730 * running on each physical CPU where possible, and avoids physical /
3731 * logical imbalances.
3733 * Called with busiest_rq locked.
3735 static void active_load_balance(struct rq *busiest_rq, int busiest_cpu)
3737 int target_cpu = busiest_rq->push_cpu;
3738 struct sched_domain *sd;
3739 struct rq *target_rq;
3741 /* Is there any task to move? */
3742 if (busiest_rq->nr_running <= 1)
3745 target_rq = cpu_rq(target_cpu);
3748 * This condition is "impossible", if it occurs
3749 * we need to fix it. Originally reported by
3750 * Bjorn Helgaas on a 128-cpu setup.
3752 BUG_ON(busiest_rq == target_rq);
3754 /* move a task from busiest_rq to target_rq */
3755 double_lock_balance(busiest_rq, target_rq);
3756 update_rq_clock(busiest_rq);
3757 update_rq_clock(target_rq);
3759 /* Search for an sd spanning us and the target CPU. */
3760 for_each_domain(target_cpu, sd) {
3761 if ((sd->flags & SD_LOAD_BALANCE) &&
3762 cpu_isset(busiest_cpu, sd->span))
3767 schedstat_inc(sd, alb_count);
3769 if (move_one_task(target_rq, target_cpu, busiest_rq,
3771 schedstat_inc(sd, alb_pushed);
3773 schedstat_inc(sd, alb_failed);
3775 double_unlock_balance(busiest_rq, target_rq);
3780 atomic_t load_balancer;
3782 } nohz ____cacheline_aligned = {
3783 .load_balancer = ATOMIC_INIT(-1),
3784 .cpu_mask = CPU_MASK_NONE,
3788 * This routine will try to nominate the ilb (idle load balancing)
3789 * owner among the cpus whose ticks are stopped. ilb owner will do the idle
3790 * load balancing on behalf of all those cpus. If all the cpus in the system
3791 * go into this tickless mode, then there will be no ilb owner (as there is
3792 * no need for one) and all the cpus will sleep till the next wakeup event
3795 * For the ilb owner, tick is not stopped. And this tick will be used
3796 * for idle load balancing. ilb owner will still be part of
3799 * While stopping the tick, this cpu will become the ilb owner if there
3800 * is no other owner. And will be the owner till that cpu becomes busy
3801 * or if all cpus in the system stop their ticks at which point
3802 * there is no need for ilb owner.
3804 * When the ilb owner becomes busy, it nominates another owner, during the
3805 * next busy scheduler_tick()
3807 int select_nohz_load_balancer(int stop_tick)
3809 int cpu = smp_processor_id();
3812 cpu_set(cpu, nohz.cpu_mask);
3813 cpu_rq(cpu)->in_nohz_recently = 1;
3816 * If we are going offline and still the leader, give up!
3818 if (!cpu_active(cpu) &&
3819 atomic_read(&nohz.load_balancer) == cpu) {
3820 if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu)
3825 /* time for ilb owner also to sleep */
3826 if (cpus_weight(nohz.cpu_mask) == num_online_cpus()) {
3827 if (atomic_read(&nohz.load_balancer) == cpu)
3828 atomic_set(&nohz.load_balancer, -1);
3832 if (atomic_read(&nohz.load_balancer) == -1) {
3833 /* make me the ilb owner */
3834 if (atomic_cmpxchg(&nohz.load_balancer, -1, cpu) == -1)
3836 } else if (atomic_read(&nohz.load_balancer) == cpu)
3839 if (!cpu_isset(cpu, nohz.cpu_mask))
3842 cpu_clear(cpu, nohz.cpu_mask);
3844 if (atomic_read(&nohz.load_balancer) == cpu)
3845 if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu)
3852 static DEFINE_SPINLOCK(balancing);
3855 * It checks each scheduling domain to see if it is due to be balanced,
3856 * and initiates a balancing operation if so.
3858 * Balancing parameters are set up in arch_init_sched_domains.
3860 static void rebalance_domains(int cpu, enum cpu_idle_type idle)
3863 struct rq *rq = cpu_rq(cpu);
3864 unsigned long interval;
3865 struct sched_domain *sd;
3866 /* Earliest time when we have to do rebalance again */
3867 unsigned long next_balance = jiffies + 60*HZ;
3868 int update_next_balance = 0;
3872 for_each_domain(cpu, sd) {
3873 if (!(sd->flags & SD_LOAD_BALANCE))
3876 interval = sd->balance_interval;
3877 if (idle != CPU_IDLE)
3878 interval *= sd->busy_factor;
3880 /* scale ms to jiffies */
3881 interval = msecs_to_jiffies(interval);
3882 if (unlikely(!interval))
3884 if (interval > HZ*NR_CPUS/10)
3885 interval = HZ*NR_CPUS/10;
3887 need_serialize = sd->flags & SD_SERIALIZE;
3889 if (need_serialize) {
3890 if (!spin_trylock(&balancing))
3894 if (time_after_eq(jiffies, sd->last_balance + interval)) {
3895 if (load_balance(cpu, rq, sd, idle, &balance, &tmp)) {
3897 * We've pulled tasks over so either we're no
3898 * longer idle, or one of our SMT siblings is
3901 idle = CPU_NOT_IDLE;
3903 sd->last_balance = jiffies;
3906 spin_unlock(&balancing);
3908 if (time_after(next_balance, sd->last_balance + interval)) {
3909 next_balance = sd->last_balance + interval;
3910 update_next_balance = 1;
3914 * Stop the load balance at this level. There is another
3915 * CPU in our sched group which is doing load balancing more
3923 * next_balance will be updated only when there is a need.
3924 * When the cpu is attached to null domain for ex, it will not be
3927 if (likely(update_next_balance))
3928 rq->next_balance = next_balance;
3932 * run_rebalance_domains is triggered when needed from the scheduler tick.
3933 * In CONFIG_NO_HZ case, the idle load balance owner will do the
3934 * rebalancing for all the cpus for whom scheduler ticks are stopped.
3936 static void run_rebalance_domains(struct softirq_action *h)
3938 int this_cpu = smp_processor_id();
3939 struct rq *this_rq = cpu_rq(this_cpu);
3940 enum cpu_idle_type idle = this_rq->idle_at_tick ?
3941 CPU_IDLE : CPU_NOT_IDLE;
3943 rebalance_domains(this_cpu, idle);
3947 * If this cpu is the owner for idle load balancing, then do the
3948 * balancing on behalf of the other idle cpus whose ticks are
3951 if (this_rq->idle_at_tick &&
3952 atomic_read(&nohz.load_balancer) == this_cpu) {
3953 cpumask_t cpus = nohz.cpu_mask;
3957 cpu_clear(this_cpu, cpus);
3958 for_each_cpu_mask_nr(balance_cpu, cpus) {
3960 * If this cpu gets work to do, stop the load balancing
3961 * work being done for other cpus. Next load
3962 * balancing owner will pick it up.
3967 rebalance_domains(balance_cpu, CPU_IDLE);
3969 rq = cpu_rq(balance_cpu);
3970 if (time_after(this_rq->next_balance, rq->next_balance))
3971 this_rq->next_balance = rq->next_balance;
3978 * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
3980 * In case of CONFIG_NO_HZ, this is the place where we nominate a new
3981 * idle load balancing owner or decide to stop the periodic load balancing,
3982 * if the whole system is idle.
3984 static inline void trigger_load_balance(struct rq *rq, int cpu)
3988 * If we were in the nohz mode recently and busy at the current
3989 * scheduler tick, then check if we need to nominate new idle
3992 if (rq->in_nohz_recently && !rq->idle_at_tick) {
3993 rq->in_nohz_recently = 0;
3995 if (atomic_read(&nohz.load_balancer) == cpu) {
3996 cpu_clear(cpu, nohz.cpu_mask);
3997 atomic_set(&nohz.load_balancer, -1);
4000 if (atomic_read(&nohz.load_balancer) == -1) {
4002 * simple selection for now: Nominate the
4003 * first cpu in the nohz list to be the next
4006 * TBD: Traverse the sched domains and nominate
4007 * the nearest cpu in the nohz.cpu_mask.
4009 int ilb = first_cpu(nohz.cpu_mask);
4011 if (ilb < nr_cpu_ids)
4017 * If this cpu is idle and doing idle load balancing for all the
4018 * cpus with ticks stopped, is it time for that to stop?
4020 if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) == cpu &&
4021 cpus_weight(nohz.cpu_mask) == num_online_cpus()) {
4027 * If this cpu is idle and the idle load balancing is done by
4028 * someone else, then no need raise the SCHED_SOFTIRQ
4030 if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) != cpu &&
4031 cpu_isset(cpu, nohz.cpu_mask))
4034 if (time_after_eq(jiffies, rq->next_balance))
4035 raise_softirq(SCHED_SOFTIRQ);
4038 #else /* CONFIG_SMP */
4041 * on UP we do not need to balance between CPUs:
4043 static inline void idle_balance(int cpu, struct rq *rq)
4049 DEFINE_PER_CPU(struct kernel_stat, kstat);
4051 EXPORT_PER_CPU_SYMBOL(kstat);
4054 * Return any ns on the sched_clock that have not yet been banked in
4055 * @p in case that task is currently running.
4057 unsigned long long task_delta_exec(struct task_struct *p)
4059 unsigned long flags;
4063 rq = task_rq_lock(p, &flags);
4065 if (task_current(rq, p)) {
4068 update_rq_clock(rq);
4069 delta_exec = rq->clock - p->se.exec_start;
4070 if ((s64)delta_exec > 0)
4074 task_rq_unlock(rq, &flags);
4080 * Account user cpu time to a process.
4081 * @p: the process that the cpu time gets accounted to
4082 * @cputime: the cpu time spent in user space since the last update
4083 * @cputime_scaled: cputime scaled by cpu frequency
4085 void account_user_time(struct task_struct *p, cputime_t cputime,
4086 cputime_t cputime_scaled)
4088 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
4091 /* Add user time to process. */
4092 p->utime = cputime_add(p->utime, cputime);
4093 p->utimescaled = cputime_add(p->utimescaled, cputime_scaled);
4094 account_group_user_time(p, cputime);
4096 /* Add user time to cpustat. */
4097 tmp = cputime_to_cputime64(cputime);
4098 if (TASK_NICE(p) > 0)
4099 cpustat->nice = cputime64_add(cpustat->nice, tmp);
4101 cpustat->user = cputime64_add(cpustat->user, tmp);
4102 /* Account for user time used */
4103 acct_update_integrals(p);
4107 * Account guest cpu time to a process.
4108 * @p: the process that the cpu time gets accounted to
4109 * @cputime: the cpu time spent in virtual machine since the last update
4110 * @cputime_scaled: cputime scaled by cpu frequency
4112 static void account_guest_time(struct task_struct *p, cputime_t cputime,
4113 cputime_t cputime_scaled)
4116 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
4118 tmp = cputime_to_cputime64(cputime);
4120 /* Add guest time to process. */
4121 p->utime = cputime_add(p->utime, cputime);
4122 p->utimescaled = cputime_add(p->utimescaled, cputime_scaled);
4123 account_group_user_time(p, cputime);
4124 p->gtime = cputime_add(p->gtime, cputime);
4126 /* Add guest time to cpustat. */
4127 cpustat->user = cputime64_add(cpustat->user, tmp);
4128 cpustat->guest = cputime64_add(cpustat->guest, tmp);
4132 * Account system cpu time to a process.
4133 * @p: the process that the cpu time gets accounted to
4134 * @hardirq_offset: the offset to subtract from hardirq_count()
4135 * @cputime: the cpu time spent in kernel space since the last update
4136 * @cputime_scaled: cputime scaled by cpu frequency
4138 void account_system_time(struct task_struct *p, int hardirq_offset,
4139 cputime_t cputime, cputime_t cputime_scaled)
4141 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
4144 if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
4145 account_guest_time(p, cputime, cputime_scaled);
4149 /* Add system time to process. */
4150 p->stime = cputime_add(p->stime, cputime);
4151 p->stimescaled = cputime_add(p->stimescaled, cputime_scaled);
4152 account_group_system_time(p, cputime);
4154 /* Add system time to cpustat. */
4155 tmp = cputime_to_cputime64(cputime);
4156 if (hardirq_count() - hardirq_offset)
4157 cpustat->irq = cputime64_add(cpustat->irq, tmp);
4158 else if (softirq_count())
4159 cpustat->softirq = cputime64_add(cpustat->softirq, tmp);
4161 cpustat->system = cputime64_add(cpustat->system, tmp);
4163 /* Account for system time used */
4164 acct_update_integrals(p);
4168 * Account for involuntary wait time.
4169 * @steal: the cpu time spent in involuntary wait
4171 void account_steal_time(cputime_t cputime)
4173 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
4174 cputime64_t cputime64 = cputime_to_cputime64(cputime);
4176 cpustat->steal = cputime64_add(cpustat->steal, cputime64);
4180 * Account for idle time.
4181 * @cputime: the cpu time spent in idle wait
4183 void account_idle_time(cputime_t cputime)
4185 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
4186 cputime64_t cputime64 = cputime_to_cputime64(cputime);
4187 struct rq *rq = this_rq();
4189 if (atomic_read(&rq->nr_iowait) > 0)
4190 cpustat->iowait = cputime64_add(cpustat->iowait, cputime64);
4192 cpustat->idle = cputime64_add(cpustat->idle, cputime64);
4195 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
4198 * Account a single tick of cpu time.
4199 * @p: the process that the cpu time gets accounted to
4200 * @user_tick: indicates if the tick is a user or a system tick
4202 void account_process_tick(struct task_struct *p, int user_tick)
4204 cputime_t one_jiffy = jiffies_to_cputime(1);
4205 cputime_t one_jiffy_scaled = cputime_to_scaled(one_jiffy);
4206 struct rq *rq = this_rq();
4209 account_user_time(p, one_jiffy, one_jiffy_scaled);
4210 else if (p != rq->idle)
4211 account_system_time(p, HARDIRQ_OFFSET, one_jiffy,
4214 account_idle_time(one_jiffy);
4218 * Account multiple ticks of steal time.
4219 * @p: the process from which the cpu time has been stolen
4220 * @ticks: number of stolen ticks
4222 void account_steal_ticks(unsigned long ticks)
4224 account_steal_time(jiffies_to_cputime(ticks));
4228 * Account multiple ticks of idle time.
4229 * @ticks: number of stolen ticks
4231 void account_idle_ticks(unsigned long ticks)
4233 account_idle_time(jiffies_to_cputime(ticks));
4239 * Use precise platform statistics if available:
4241 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
4242 cputime_t task_utime(struct task_struct *p)
4247 cputime_t task_stime(struct task_struct *p)
4252 cputime_t task_utime(struct task_struct *p)
4254 clock_t utime = cputime_to_clock_t(p->utime),
4255 total = utime + cputime_to_clock_t(p->stime);
4259 * Use CFS's precise accounting:
4261 temp = (u64)nsec_to_clock_t(p->se.sum_exec_runtime);
4265 do_div(temp, total);
4267 utime = (clock_t)temp;
4269 p->prev_utime = max(p->prev_utime, clock_t_to_cputime(utime));
4270 return p->prev_utime;
4273 cputime_t task_stime(struct task_struct *p)
4278 * Use CFS's precise accounting. (we subtract utime from
4279 * the total, to make sure the total observed by userspace
4280 * grows monotonically - apps rely on that):
4282 stime = nsec_to_clock_t(p->se.sum_exec_runtime) -
4283 cputime_to_clock_t(task_utime(p));
4286 p->prev_stime = max(p->prev_stime, clock_t_to_cputime(stime));
4288 return p->prev_stime;
4292 inline cputime_t task_gtime(struct task_struct *p)
4298 * This function gets called by the timer code, with HZ frequency.
4299 * We call it with interrupts disabled.
4301 * It also gets called by the fork code, when changing the parent's
4304 void scheduler_tick(void)
4306 int cpu = smp_processor_id();
4307 struct rq *rq = cpu_rq(cpu);
4308 struct task_struct *curr = rq->curr;
4312 spin_lock(&rq->lock);
4313 update_rq_clock(rq);
4314 update_cpu_load(rq);
4315 curr->sched_class->task_tick(rq, curr, 0);
4316 spin_unlock(&rq->lock);
4319 rq->idle_at_tick = idle_cpu(cpu);
4320 trigger_load_balance(rq, cpu);
4324 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
4325 defined(CONFIG_PREEMPT_TRACER))
4327 static inline unsigned long get_parent_ip(unsigned long addr)
4329 if (in_lock_functions(addr)) {
4330 addr = CALLER_ADDR2;
4331 if (in_lock_functions(addr))
4332 addr = CALLER_ADDR3;
4337 void __kprobes add_preempt_count(int val)
4339 #ifdef CONFIG_DEBUG_PREEMPT
4343 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
4346 preempt_count() += val;
4347 #ifdef CONFIG_DEBUG_PREEMPT
4349 * Spinlock count overflowing soon?
4351 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
4354 if (preempt_count() == val)
4355 trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
4357 EXPORT_SYMBOL(add_preempt_count);
4359 void __kprobes sub_preempt_count(int val)
4361 #ifdef CONFIG_DEBUG_PREEMPT
4365 if (DEBUG_LOCKS_WARN_ON(val > preempt_count() - (!!kernel_locked())))
4368 * Is the spinlock portion underflowing?
4370 if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
4371 !(preempt_count() & PREEMPT_MASK)))
4375 if (preempt_count() == val)
4376 trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
4377 preempt_count() -= val;
4379 EXPORT_SYMBOL(sub_preempt_count);
4384 * Print scheduling while atomic bug:
4386 static noinline void __schedule_bug(struct task_struct *prev)
4388 struct pt_regs *regs = get_irq_regs();
4390 printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
4391 prev->comm, prev->pid, preempt_count());
4393 debug_show_held_locks(prev);
4395 if (irqs_disabled())
4396 print_irqtrace_events(prev);
4405 * Various schedule()-time debugging checks and statistics:
4407 static inline void schedule_debug(struct task_struct *prev)
4410 * Test if we are atomic. Since do_exit() needs to call into
4411 * schedule() atomically, we ignore that path for now.
4412 * Otherwise, whine if we are scheduling when we should not be.
4414 if (unlikely(in_atomic_preempt_off() && !prev->exit_state))
4415 __schedule_bug(prev);
4417 profile_hit(SCHED_PROFILING, __builtin_return_address(0));
4419 schedstat_inc(this_rq(), sched_count);
4420 #ifdef CONFIG_SCHEDSTATS
4421 if (unlikely(prev->lock_depth >= 0)) {
4422 schedstat_inc(this_rq(), bkl_count);
4423 schedstat_inc(prev, sched_info.bkl_count);
4429 * Pick up the highest-prio task:
4431 static inline struct task_struct *
4432 pick_next_task(struct rq *rq, struct task_struct *prev)
4434 const struct sched_class *class;
4435 struct task_struct *p;
4438 * Optimization: we know that if all tasks are in
4439 * the fair class we can call that function directly:
4441 if (likely(rq->nr_running == rq->cfs.nr_running)) {
4442 p = fair_sched_class.pick_next_task(rq);
4447 class = sched_class_highest;
4449 p = class->pick_next_task(rq);
4453 * Will never be NULL as the idle class always
4454 * returns a non-NULL p:
4456 class = class->next;
4461 * schedule() is the main scheduler function.
4463 asmlinkage void __sched schedule(void)
4465 struct task_struct *prev, *next;
4466 unsigned long *switch_count;
4472 cpu = smp_processor_id();
4476 switch_count = &prev->nivcsw;
4478 release_kernel_lock(prev);
4479 need_resched_nonpreemptible:
4481 schedule_debug(prev);
4483 if (sched_feat(HRTICK))
4486 spin_lock_irq(&rq->lock);
4487 update_rq_clock(rq);
4488 clear_tsk_need_resched(prev);
4490 if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
4491 if (unlikely(signal_pending_state(prev->state, prev)))
4492 prev->state = TASK_RUNNING;
4494 deactivate_task(rq, prev, 1);
4495 switch_count = &prev->nvcsw;
4499 if (prev->sched_class->pre_schedule)
4500 prev->sched_class->pre_schedule(rq, prev);
4503 if (unlikely(!rq->nr_running))
4504 idle_balance(cpu, rq);
4506 prev->sched_class->put_prev_task(rq, prev);
4507 next = pick_next_task(rq, prev);
4509 if (likely(prev != next)) {
4510 sched_info_switch(prev, next);
4516 context_switch(rq, prev, next); /* unlocks the rq */
4518 * the context switch might have flipped the stack from under
4519 * us, hence refresh the local variables.
4521 cpu = smp_processor_id();
4524 spin_unlock_irq(&rq->lock);
4526 if (unlikely(reacquire_kernel_lock(current) < 0))
4527 goto need_resched_nonpreemptible;
4529 preempt_enable_no_resched();
4530 if (unlikely(test_thread_flag(TIF_NEED_RESCHED)))
4533 EXPORT_SYMBOL(schedule);
4535 #ifdef CONFIG_PREEMPT
4537 * this is the entry point to schedule() from in-kernel preemption
4538 * off of preempt_enable. Kernel preemptions off return from interrupt
4539 * occur there and call schedule directly.
4541 asmlinkage void __sched preempt_schedule(void)
4543 struct thread_info *ti = current_thread_info();
4546 * If there is a non-zero preempt_count or interrupts are disabled,
4547 * we do not want to preempt the current task. Just return..
4549 if (likely(ti->preempt_count || irqs_disabled()))
4553 add_preempt_count(PREEMPT_ACTIVE);
4555 sub_preempt_count(PREEMPT_ACTIVE);
4558 * Check again in case we missed a preemption opportunity
4559 * between schedule and now.
4562 } while (unlikely(test_thread_flag(TIF_NEED_RESCHED)));
4564 EXPORT_SYMBOL(preempt_schedule);
4567 * this is the entry point to schedule() from kernel preemption
4568 * off of irq context.
4569 * Note, that this is called and return with irqs disabled. This will
4570 * protect us against recursive calling from irq.
4572 asmlinkage void __sched preempt_schedule_irq(void)
4574 struct thread_info *ti = current_thread_info();
4576 /* Catch callers which need to be fixed */
4577 BUG_ON(ti->preempt_count || !irqs_disabled());
4580 add_preempt_count(PREEMPT_ACTIVE);
4583 local_irq_disable();
4584 sub_preempt_count(PREEMPT_ACTIVE);
4587 * Check again in case we missed a preemption opportunity
4588 * between schedule and now.
4591 } while (unlikely(test_thread_flag(TIF_NEED_RESCHED)));
4594 #endif /* CONFIG_PREEMPT */
4596 int default_wake_function(wait_queue_t *curr, unsigned mode, int sync,
4599 return try_to_wake_up(curr->private, mode, sync);
4601 EXPORT_SYMBOL(default_wake_function);
4604 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
4605 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
4606 * number) then we wake all the non-exclusive tasks and one exclusive task.
4608 * There are circumstances in which we can try to wake a task which has already
4609 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
4610 * zero in this (rare) case, and we handle it by continuing to scan the queue.
4612 static void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
4613 int nr_exclusive, int sync, void *key)
4615 wait_queue_t *curr, *next;
4617 list_for_each_entry_safe(curr, next, &q->task_list, task_list) {
4618 unsigned flags = curr->flags;
4620 if (curr->func(curr, mode, sync, key) &&
4621 (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive)
4627 * __wake_up - wake up threads blocked on a waitqueue.
4629 * @mode: which threads
4630 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4631 * @key: is directly passed to the wakeup function
4633 void __wake_up(wait_queue_head_t *q, unsigned int mode,
4634 int nr_exclusive, void *key)
4636 unsigned long flags;
4638 spin_lock_irqsave(&q->lock, flags);
4639 __wake_up_common(q, mode, nr_exclusive, 0, key);
4640 spin_unlock_irqrestore(&q->lock, flags);
4642 EXPORT_SYMBOL(__wake_up);
4645 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
4647 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode)
4649 __wake_up_common(q, mode, 1, 0, NULL);
4653 * __wake_up_sync - wake up threads blocked on a waitqueue.
4655 * @mode: which threads
4656 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4658 * The sync wakeup differs that the waker knows that it will schedule
4659 * away soon, so while the target thread will be woken up, it will not
4660 * be migrated to another CPU - ie. the two threads are 'synchronized'
4661 * with each other. This can prevent needless bouncing between CPUs.
4663 * On UP it can prevent extra preemption.
4666 __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
4668 unsigned long flags;
4674 if (unlikely(!nr_exclusive))
4677 spin_lock_irqsave(&q->lock, flags);
4678 __wake_up_common(q, mode, nr_exclusive, sync, NULL);
4679 spin_unlock_irqrestore(&q->lock, flags);
4681 EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */
4684 * complete: - signals a single thread waiting on this completion
4685 * @x: holds the state of this particular completion
4687 * This will wake up a single thread waiting on this completion. Threads will be
4688 * awakened in the same order in which they were queued.
4690 * See also complete_all(), wait_for_completion() and related routines.
4692 void complete(struct completion *x)
4694 unsigned long flags;
4696 spin_lock_irqsave(&x->wait.lock, flags);
4698 __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL);
4699 spin_unlock_irqrestore(&x->wait.lock, flags);
4701 EXPORT_SYMBOL(complete);
4704 * complete_all: - signals all threads waiting on this completion
4705 * @x: holds the state of this particular completion
4707 * This will wake up all threads waiting on this particular completion event.
4709 void complete_all(struct completion *x)
4711 unsigned long flags;
4713 spin_lock_irqsave(&x->wait.lock, flags);
4714 x->done += UINT_MAX/2;
4715 __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL);
4716 spin_unlock_irqrestore(&x->wait.lock, flags);
4718 EXPORT_SYMBOL(complete_all);
4720 static inline long __sched
4721 do_wait_for_common(struct completion *x, long timeout, int state)
4724 DECLARE_WAITQUEUE(wait, current);
4726 wait.flags |= WQ_FLAG_EXCLUSIVE;
4727 __add_wait_queue_tail(&x->wait, &wait);
4729 if (signal_pending_state(state, current)) {
4730 timeout = -ERESTARTSYS;
4733 __set_current_state(state);
4734 spin_unlock_irq(&x->wait.lock);
4735 timeout = schedule_timeout(timeout);
4736 spin_lock_irq(&x->wait.lock);
4737 } while (!x->done && timeout);
4738 __remove_wait_queue(&x->wait, &wait);
4743 return timeout ?: 1;
4747 wait_for_common(struct completion *x, long timeout, int state)
4751 spin_lock_irq(&x->wait.lock);
4752 timeout = do_wait_for_common(x, timeout, state);
4753 spin_unlock_irq(&x->wait.lock);
4758 * wait_for_completion: - waits for completion of a task
4759 * @x: holds the state of this particular completion
4761 * This waits to be signaled for completion of a specific task. It is NOT
4762 * interruptible and there is no timeout.
4764 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
4765 * and interrupt capability. Also see complete().
4767 void __sched wait_for_completion(struct completion *x)
4769 wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE);
4771 EXPORT_SYMBOL(wait_for_completion);
4774 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
4775 * @x: holds the state of this particular completion
4776 * @timeout: timeout value in jiffies
4778 * This waits for either a completion of a specific task to be signaled or for a
4779 * specified timeout to expire. The timeout is in jiffies. It is not
4782 unsigned long __sched
4783 wait_for_completion_timeout(struct completion *x, unsigned long timeout)
4785 return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE);
4787 EXPORT_SYMBOL(wait_for_completion_timeout);
4790 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
4791 * @x: holds the state of this particular completion
4793 * This waits for completion of a specific task to be signaled. It is
4796 int __sched wait_for_completion_interruptible(struct completion *x)
4798 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE);
4799 if (t == -ERESTARTSYS)
4803 EXPORT_SYMBOL(wait_for_completion_interruptible);
4806 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
4807 * @x: holds the state of this particular completion
4808 * @timeout: timeout value in jiffies
4810 * This waits for either a completion of a specific task to be signaled or for a
4811 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
4813 unsigned long __sched
4814 wait_for_completion_interruptible_timeout(struct completion *x,
4815 unsigned long timeout)
4817 return wait_for_common(x, timeout, TASK_INTERRUPTIBLE);
4819 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout);
4822 * wait_for_completion_killable: - waits for completion of a task (killable)
4823 * @x: holds the state of this particular completion
4825 * This waits to be signaled for completion of a specific task. It can be
4826 * interrupted by a kill signal.
4828 int __sched wait_for_completion_killable(struct completion *x)
4830 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE);
4831 if (t == -ERESTARTSYS)
4835 EXPORT_SYMBOL(wait_for_completion_killable);
4838 * try_wait_for_completion - try to decrement a completion without blocking
4839 * @x: completion structure
4841 * Returns: 0 if a decrement cannot be done without blocking
4842 * 1 if a decrement succeeded.
4844 * If a completion is being used as a counting completion,
4845 * attempt to decrement the counter without blocking. This
4846 * enables us to avoid waiting if the resource the completion
4847 * is protecting is not available.
4849 bool try_wait_for_completion(struct completion *x)
4853 spin_lock_irq(&x->wait.lock);
4858 spin_unlock_irq(&x->wait.lock);
4861 EXPORT_SYMBOL(try_wait_for_completion);
4864 * completion_done - Test to see if a completion has any waiters
4865 * @x: completion structure
4867 * Returns: 0 if there are waiters (wait_for_completion() in progress)
4868 * 1 if there are no waiters.
4871 bool completion_done(struct completion *x)
4875 spin_lock_irq(&x->wait.lock);
4878 spin_unlock_irq(&x->wait.lock);
4881 EXPORT_SYMBOL(completion_done);
4884 sleep_on_common(wait_queue_head_t *q, int state, long timeout)
4886 unsigned long flags;
4889 init_waitqueue_entry(&wait, current);
4891 __set_current_state(state);
4893 spin_lock_irqsave(&q->lock, flags);
4894 __add_wait_queue(q, &wait);
4895 spin_unlock(&q->lock);
4896 timeout = schedule_timeout(timeout);
4897 spin_lock_irq(&q->lock);
4898 __remove_wait_queue(q, &wait);
4899 spin_unlock_irqrestore(&q->lock, flags);
4904 void __sched interruptible_sleep_on(wait_queue_head_t *q)
4906 sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
4908 EXPORT_SYMBOL(interruptible_sleep_on);
4911 interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout)
4913 return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout);
4915 EXPORT_SYMBOL(interruptible_sleep_on_timeout);
4917 void __sched sleep_on(wait_queue_head_t *q)
4919 sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
4921 EXPORT_SYMBOL(sleep_on);
4923 long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout)
4925 return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout);
4927 EXPORT_SYMBOL(sleep_on_timeout);
4929 #ifdef CONFIG_RT_MUTEXES
4932 * rt_mutex_setprio - set the current priority of a task
4934 * @prio: prio value (kernel-internal form)
4936 * This function changes the 'effective' priority of a task. It does
4937 * not touch ->normal_prio like __setscheduler().
4939 * Used by the rt_mutex code to implement priority inheritance logic.
4941 void rt_mutex_setprio(struct task_struct *p, int prio)
4943 unsigned long flags;
4944 int oldprio, on_rq, running;
4946 const struct sched_class *prev_class = p->sched_class;
4948 BUG_ON(prio < 0 || prio > MAX_PRIO);
4950 rq = task_rq_lock(p, &flags);
4951 update_rq_clock(rq);
4954 on_rq = p->se.on_rq;
4955 running = task_current(rq, p);
4957 dequeue_task(rq, p, 0);
4959 p->sched_class->put_prev_task(rq, p);
4962 p->sched_class = &rt_sched_class;
4964 p->sched_class = &fair_sched_class;
4969 p->sched_class->set_curr_task(rq);
4971 enqueue_task(rq, p, 0);
4973 check_class_changed(rq, p, prev_class, oldprio, running);
4975 task_rq_unlock(rq, &flags);
4980 void set_user_nice(struct task_struct *p, long nice)
4982 int old_prio, delta, on_rq;
4983 unsigned long flags;
4986 if (TASK_NICE(p) == nice || nice < -20 || nice > 19)
4989 * We have to be careful, if called from sys_setpriority(),
4990 * the task might be in the middle of scheduling on another CPU.
4992 rq = task_rq_lock(p, &flags);
4993 update_rq_clock(rq);
4995 * The RT priorities are set via sched_setscheduler(), but we still
4996 * allow the 'normal' nice value to be set - but as expected
4997 * it wont have any effect on scheduling until the task is
4998 * SCHED_FIFO/SCHED_RR:
5000 if (task_has_rt_policy(p)) {
5001 p->static_prio = NICE_TO_PRIO(nice);
5004 on_rq = p->se.on_rq;
5006 dequeue_task(rq, p, 0);
5008 p->static_prio = NICE_TO_PRIO(nice);
5011 p->prio = effective_prio(p);
5012 delta = p->prio - old_prio;
5015 enqueue_task(rq, p, 0);
5017 * If the task increased its priority or is running and
5018 * lowered its priority, then reschedule its CPU:
5020 if (delta < 0 || (delta > 0 && task_running(rq, p)))
5021 resched_task(rq->curr);
5024 task_rq_unlock(rq, &flags);
5026 EXPORT_SYMBOL(set_user_nice);
5029 * can_nice - check if a task can reduce its nice value
5033 int can_nice(const struct task_struct *p, const int nice)
5035 /* convert nice value [19,-20] to rlimit style value [1,40] */
5036 int nice_rlim = 20 - nice;
5038 return (nice_rlim <= p->signal->rlim[RLIMIT_NICE].rlim_cur ||
5039 capable(CAP_SYS_NICE));
5042 #ifdef __ARCH_WANT_SYS_NICE
5045 * sys_nice - change the priority of the current process.
5046 * @increment: priority increment
5048 * sys_setpriority is a more generic, but much slower function that
5049 * does similar things.
5051 asmlinkage long sys_nice(int increment)
5056 * Setpriority might change our priority at the same moment.
5057 * We don't have to worry. Conceptually one call occurs first
5058 * and we have a single winner.
5060 if (increment < -40)
5065 nice = PRIO_TO_NICE(current->static_prio) + increment;
5071 if (increment < 0 && !can_nice(current, nice))
5074 retval = security_task_setnice(current, nice);
5078 set_user_nice(current, nice);
5085 * task_prio - return the priority value of a given task.
5086 * @p: the task in question.
5088 * This is the priority value as seen by users in /proc.
5089 * RT tasks are offset by -200. Normal tasks are centered
5090 * around 0, value goes from -16 to +15.
5092 int task_prio(const struct task_struct *p)
5094 return p->prio - MAX_RT_PRIO;
5098 * task_nice - return the nice value of a given task.
5099 * @p: the task in question.
5101 int task_nice(const struct task_struct *p)
5103 return TASK_NICE(p);
5105 EXPORT_SYMBOL(task_nice);
5108 * idle_cpu - is a given cpu idle currently?
5109 * @cpu: the processor in question.
5111 int idle_cpu(int cpu)
5113 return cpu_curr(cpu) == cpu_rq(cpu)->idle;
5117 * idle_task - return the idle task for a given cpu.
5118 * @cpu: the processor in question.
5120 struct task_struct *idle_task(int cpu)
5122 return cpu_rq(cpu)->idle;
5126 * find_process_by_pid - find a process with a matching PID value.
5127 * @pid: the pid in question.
5129 static struct task_struct *find_process_by_pid(pid_t pid)
5131 return pid ? find_task_by_vpid(pid) : current;
5134 /* Actually do priority change: must hold rq lock. */
5136 __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio)
5138 BUG_ON(p->se.on_rq);
5141 switch (p->policy) {
5145 p->sched_class = &fair_sched_class;
5149 p->sched_class = &rt_sched_class;
5153 p->rt_priority = prio;
5154 p->normal_prio = normal_prio(p);
5155 /* we are holding p->pi_lock already */
5156 p->prio = rt_mutex_getprio(p);
5161 * check the target process has a UID that matches the current process's
5163 static bool check_same_owner(struct task_struct *p)
5165 const struct cred *cred = current_cred(), *pcred;
5169 pcred = __task_cred(p);
5170 match = (cred->euid == pcred->euid ||
5171 cred->euid == pcred->uid);
5176 static int __sched_setscheduler(struct task_struct *p, int policy,
5177 struct sched_param *param, bool user)
5179 int retval, oldprio, oldpolicy = -1, on_rq, running;
5180 unsigned long flags;
5181 const struct sched_class *prev_class = p->sched_class;
5184 /* may grab non-irq protected spin_locks */
5185 BUG_ON(in_interrupt());
5187 /* double check policy once rq lock held */
5189 policy = oldpolicy = p->policy;
5190 else if (policy != SCHED_FIFO && policy != SCHED_RR &&
5191 policy != SCHED_NORMAL && policy != SCHED_BATCH &&
5192 policy != SCHED_IDLE)
5195 * Valid priorities for SCHED_FIFO and SCHED_RR are
5196 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
5197 * SCHED_BATCH and SCHED_IDLE is 0.
5199 if (param->sched_priority < 0 ||
5200 (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) ||
5201 (!p->mm && param->sched_priority > MAX_RT_PRIO-1))
5203 if (rt_policy(policy) != (param->sched_priority != 0))
5207 * Allow unprivileged RT tasks to decrease priority:
5209 if (user && !capable(CAP_SYS_NICE)) {
5210 if (rt_policy(policy)) {
5211 unsigned long rlim_rtprio;
5213 if (!lock_task_sighand(p, &flags))
5215 rlim_rtprio = p->signal->rlim[RLIMIT_RTPRIO].rlim_cur;
5216 unlock_task_sighand(p, &flags);
5218 /* can't set/change the rt policy */
5219 if (policy != p->policy && !rlim_rtprio)
5222 /* can't increase priority */
5223 if (param->sched_priority > p->rt_priority &&
5224 param->sched_priority > rlim_rtprio)
5228 * Like positive nice levels, dont allow tasks to
5229 * move out of SCHED_IDLE either:
5231 if (p->policy == SCHED_IDLE && policy != SCHED_IDLE)
5234 /* can't change other user's priorities */
5235 if (!check_same_owner(p))
5240 #ifdef CONFIG_RT_GROUP_SCHED
5242 * Do not allow realtime tasks into groups that have no runtime
5245 if (rt_bandwidth_enabled() && rt_policy(policy) &&
5246 task_group(p)->rt_bandwidth.rt_runtime == 0)
5250 retval = security_task_setscheduler(p, policy, param);
5256 * make sure no PI-waiters arrive (or leave) while we are
5257 * changing the priority of the task:
5259 spin_lock_irqsave(&p->pi_lock, flags);
5261 * To be able to change p->policy safely, the apropriate
5262 * runqueue lock must be held.
5264 rq = __task_rq_lock(p);
5265 /* recheck policy now with rq lock held */
5266 if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
5267 policy = oldpolicy = -1;
5268 __task_rq_unlock(rq);
5269 spin_unlock_irqrestore(&p->pi_lock, flags);
5272 update_rq_clock(rq);
5273 on_rq = p->se.on_rq;
5274 running = task_current(rq, p);
5276 deactivate_task(rq, p, 0);
5278 p->sched_class->put_prev_task(rq, p);
5281 __setscheduler(rq, p, policy, param->sched_priority);
5284 p->sched_class->set_curr_task(rq);
5286 activate_task(rq, p, 0);
5288 check_class_changed(rq, p, prev_class, oldprio, running);
5290 __task_rq_unlock(rq);
5291 spin_unlock_irqrestore(&p->pi_lock, flags);
5293 rt_mutex_adjust_pi(p);
5299 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
5300 * @p: the task in question.
5301 * @policy: new policy.
5302 * @param: structure containing the new RT priority.
5304 * NOTE that the task may be already dead.
5306 int sched_setscheduler(struct task_struct *p, int policy,
5307 struct sched_param *param)
5309 return __sched_setscheduler(p, policy, param, true);
5311 EXPORT_SYMBOL_GPL(sched_setscheduler);
5314 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
5315 * @p: the task in question.
5316 * @policy: new policy.
5317 * @param: structure containing the new RT priority.
5319 * Just like sched_setscheduler, only don't bother checking if the
5320 * current context has permission. For example, this is needed in
5321 * stop_machine(): we create temporary high priority worker threads,
5322 * but our caller might not have that capability.
5324 int sched_setscheduler_nocheck(struct task_struct *p, int policy,
5325 struct sched_param *param)
5327 return __sched_setscheduler(p, policy, param, false);
5331 do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
5333 struct sched_param lparam;
5334 struct task_struct *p;
5337 if (!param || pid < 0)
5339 if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
5344 p = find_process_by_pid(pid);
5346 retval = sched_setscheduler(p, policy, &lparam);
5353 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
5354 * @pid: the pid in question.
5355 * @policy: new policy.
5356 * @param: structure containing the new RT priority.
5359 sys_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
5361 /* negative values for policy are not valid */
5365 return do_sched_setscheduler(pid, policy, param);
5369 * sys_sched_setparam - set/change the RT priority of a thread
5370 * @pid: the pid in question.
5371 * @param: structure containing the new RT priority.
5373 asmlinkage long sys_sched_setparam(pid_t pid, struct sched_param __user *param)
5375 return do_sched_setscheduler(pid, -1, param);
5379 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
5380 * @pid: the pid in question.
5382 asmlinkage long sys_sched_getscheduler(pid_t pid)
5384 struct task_struct *p;
5391 read_lock(&tasklist_lock);
5392 p = find_process_by_pid(pid);
5394 retval = security_task_getscheduler(p);
5398 read_unlock(&tasklist_lock);
5403 * sys_sched_getscheduler - get the RT priority of a thread
5404 * @pid: the pid in question.
5405 * @param: structure containing the RT priority.
5407 asmlinkage long sys_sched_getparam(pid_t pid, struct sched_param __user *param)
5409 struct sched_param lp;
5410 struct task_struct *p;
5413 if (!param || pid < 0)
5416 read_lock(&tasklist_lock);
5417 p = find_process_by_pid(pid);
5422 retval = security_task_getscheduler(p);
5426 lp.sched_priority = p->rt_priority;
5427 read_unlock(&tasklist_lock);
5430 * This one might sleep, we cannot do it with a spinlock held ...
5432 retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;
5437 read_unlock(&tasklist_lock);
5441 long sched_setaffinity(pid_t pid, const cpumask_t *in_mask)
5443 cpumask_t cpus_allowed;
5444 cpumask_t new_mask = *in_mask;
5445 struct task_struct *p;
5449 read_lock(&tasklist_lock);
5451 p = find_process_by_pid(pid);
5453 read_unlock(&tasklist_lock);
5459 * It is not safe to call set_cpus_allowed with the
5460 * tasklist_lock held. We will bump the task_struct's
5461 * usage count and then drop tasklist_lock.
5464 read_unlock(&tasklist_lock);
5467 if (!check_same_owner(p) && !capable(CAP_SYS_NICE))
5470 retval = security_task_setscheduler(p, 0, NULL);
5474 cpuset_cpus_allowed(p, &cpus_allowed);
5475 cpus_and(new_mask, new_mask, cpus_allowed);
5477 retval = set_cpus_allowed_ptr(p, &new_mask);
5480 cpuset_cpus_allowed(p, &cpus_allowed);
5481 if (!cpus_subset(new_mask, cpus_allowed)) {
5483 * We must have raced with a concurrent cpuset
5484 * update. Just reset the cpus_allowed to the
5485 * cpuset's cpus_allowed
5487 new_mask = cpus_allowed;
5497 static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
5498 cpumask_t *new_mask)
5500 if (len < sizeof(cpumask_t)) {
5501 memset(new_mask, 0, sizeof(cpumask_t));
5502 } else if (len > sizeof(cpumask_t)) {
5503 len = sizeof(cpumask_t);
5505 return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
5509 * sys_sched_setaffinity - set the cpu affinity of a process
5510 * @pid: pid of the process
5511 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5512 * @user_mask_ptr: user-space pointer to the new cpu mask
5514 asmlinkage long sys_sched_setaffinity(pid_t pid, unsigned int len,
5515 unsigned long __user *user_mask_ptr)
5520 retval = get_user_cpu_mask(user_mask_ptr, len, &new_mask);
5524 return sched_setaffinity(pid, &new_mask);
5527 long sched_getaffinity(pid_t pid, cpumask_t *mask)
5529 struct task_struct *p;
5533 read_lock(&tasklist_lock);
5536 p = find_process_by_pid(pid);
5540 retval = security_task_getscheduler(p);
5544 cpus_and(*mask, p->cpus_allowed, cpu_online_map);
5547 read_unlock(&tasklist_lock);
5554 * sys_sched_getaffinity - get the cpu affinity of a process
5555 * @pid: pid of the process
5556 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5557 * @user_mask_ptr: user-space pointer to hold the current cpu mask
5559 asmlinkage long sys_sched_getaffinity(pid_t pid, unsigned int len,
5560 unsigned long __user *user_mask_ptr)
5565 if (len < sizeof(cpumask_t))
5568 ret = sched_getaffinity(pid, &mask);
5572 if (copy_to_user(user_mask_ptr, &mask, sizeof(cpumask_t)))
5575 return sizeof(cpumask_t);
5579 * sys_sched_yield - yield the current processor to other threads.
5581 * This function yields the current CPU to other tasks. If there are no
5582 * other threads running on this CPU then this function will return.
5584 asmlinkage long sys_sched_yield(void)
5586 struct rq *rq = this_rq_lock();
5588 schedstat_inc(rq, yld_count);
5589 current->sched_class->yield_task(rq);
5592 * Since we are going to call schedule() anyway, there's
5593 * no need to preempt or enable interrupts:
5595 __release(rq->lock);
5596 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
5597 _raw_spin_unlock(&rq->lock);
5598 preempt_enable_no_resched();
5605 static void __cond_resched(void)
5607 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
5608 __might_sleep(__FILE__, __LINE__);
5611 * The BKS might be reacquired before we have dropped
5612 * PREEMPT_ACTIVE, which could trigger a second
5613 * cond_resched() call.
5616 add_preempt_count(PREEMPT_ACTIVE);
5618 sub_preempt_count(PREEMPT_ACTIVE);
5619 } while (need_resched());
5622 int __sched _cond_resched(void)
5624 if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE) &&
5625 system_state == SYSTEM_RUNNING) {
5631 EXPORT_SYMBOL(_cond_resched);
5634 * cond_resched_lock() - if a reschedule is pending, drop the given lock,
5635 * call schedule, and on return reacquire the lock.
5637 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
5638 * operations here to prevent schedule() from being called twice (once via
5639 * spin_unlock(), once by hand).
5641 int cond_resched_lock(spinlock_t *lock)
5643 int resched = need_resched() && system_state == SYSTEM_RUNNING;
5646 if (spin_needbreak(lock) || resched) {
5648 if (resched && need_resched())
5657 EXPORT_SYMBOL(cond_resched_lock);
5659 int __sched cond_resched_softirq(void)
5661 BUG_ON(!in_softirq());
5663 if (need_resched() && system_state == SYSTEM_RUNNING) {
5671 EXPORT_SYMBOL(cond_resched_softirq);
5674 * yield - yield the current processor to other threads.
5676 * This is a shortcut for kernel-space yielding - it marks the
5677 * thread runnable and calls sys_sched_yield().
5679 void __sched yield(void)
5681 set_current_state(TASK_RUNNING);
5684 EXPORT_SYMBOL(yield);
5687 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
5688 * that process accounting knows that this is a task in IO wait state.
5690 * But don't do that if it is a deliberate, throttling IO wait (this task
5691 * has set its backing_dev_info: the queue against which it should throttle)
5693 void __sched io_schedule(void)
5695 struct rq *rq = &__raw_get_cpu_var(runqueues);
5697 delayacct_blkio_start();
5698 atomic_inc(&rq->nr_iowait);
5700 atomic_dec(&rq->nr_iowait);
5701 delayacct_blkio_end();
5703 EXPORT_SYMBOL(io_schedule);
5705 long __sched io_schedule_timeout(long timeout)
5707 struct rq *rq = &__raw_get_cpu_var(runqueues);
5710 delayacct_blkio_start();
5711 atomic_inc(&rq->nr_iowait);
5712 ret = schedule_timeout(timeout);
5713 atomic_dec(&rq->nr_iowait);
5714 delayacct_blkio_end();
5719 * sys_sched_get_priority_max - return maximum RT priority.
5720 * @policy: scheduling class.
5722 * this syscall returns the maximum rt_priority that can be used
5723 * by a given scheduling class.
5725 asmlinkage long sys_sched_get_priority_max(int policy)
5732 ret = MAX_USER_RT_PRIO-1;
5744 * sys_sched_get_priority_min - return minimum RT priority.
5745 * @policy: scheduling class.
5747 * this syscall returns the minimum rt_priority that can be used
5748 * by a given scheduling class.
5750 asmlinkage long sys_sched_get_priority_min(int policy)
5768 * sys_sched_rr_get_interval - return the default timeslice of a process.
5769 * @pid: pid of the process.
5770 * @interval: userspace pointer to the timeslice value.
5772 * this syscall writes the default timeslice value of a given process
5773 * into the user-space timespec buffer. A value of '0' means infinity.
5776 long sys_sched_rr_get_interval(pid_t pid, struct timespec __user *interval)
5778 struct task_struct *p;
5779 unsigned int time_slice;
5787 read_lock(&tasklist_lock);
5788 p = find_process_by_pid(pid);
5792 retval = security_task_getscheduler(p);
5797 * Time slice is 0 for SCHED_FIFO tasks and for SCHED_OTHER
5798 * tasks that are on an otherwise idle runqueue:
5801 if (p->policy == SCHED_RR) {
5802 time_slice = DEF_TIMESLICE;
5803 } else if (p->policy != SCHED_FIFO) {
5804 struct sched_entity *se = &p->se;
5805 unsigned long flags;
5808 rq = task_rq_lock(p, &flags);
5809 if (rq->cfs.load.weight)
5810 time_slice = NS_TO_JIFFIES(sched_slice(&rq->cfs, se));
5811 task_rq_unlock(rq, &flags);
5813 read_unlock(&tasklist_lock);
5814 jiffies_to_timespec(time_slice, &t);
5815 retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;
5819 read_unlock(&tasklist_lock);
5823 static const char stat_nam[] = TASK_STATE_TO_CHAR_STR;
5825 void sched_show_task(struct task_struct *p)
5827 unsigned long free = 0;
5830 state = p->state ? __ffs(p->state) + 1 : 0;
5831 printk(KERN_INFO "%-13.13s %c", p->comm,
5832 state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?');
5833 #if BITS_PER_LONG == 32
5834 if (state == TASK_RUNNING)
5835 printk(KERN_CONT " running ");
5837 printk(KERN_CONT " %08lx ", thread_saved_pc(p));
5839 if (state == TASK_RUNNING)
5840 printk(KERN_CONT " running task ");
5842 printk(KERN_CONT " %016lx ", thread_saved_pc(p));
5844 #ifdef CONFIG_DEBUG_STACK_USAGE
5846 unsigned long *n = end_of_stack(p);
5849 free = (unsigned long)n - (unsigned long)end_of_stack(p);
5852 printk(KERN_CONT "%5lu %5d %6d\n", free,
5853 task_pid_nr(p), task_pid_nr(p->real_parent));
5855 show_stack(p, NULL);
5858 void show_state_filter(unsigned long state_filter)
5860 struct task_struct *g, *p;
5862 #if BITS_PER_LONG == 32
5864 " task PC stack pid father\n");
5867 " task PC stack pid father\n");
5869 read_lock(&tasklist_lock);
5870 do_each_thread(g, p) {
5872 * reset the NMI-timeout, listing all files on a slow
5873 * console might take alot of time:
5875 touch_nmi_watchdog();
5876 if (!state_filter || (p->state & state_filter))
5878 } while_each_thread(g, p);
5880 touch_all_softlockup_watchdogs();
5882 #ifdef CONFIG_SCHED_DEBUG
5883 sysrq_sched_debug_show();
5885 read_unlock(&tasklist_lock);
5887 * Only show locks if all tasks are dumped:
5889 if (state_filter == -1)
5890 debug_show_all_locks();
5893 void __cpuinit init_idle_bootup_task(struct task_struct *idle)
5895 idle->sched_class = &idle_sched_class;
5899 * init_idle - set up an idle thread for a given CPU
5900 * @idle: task in question
5901 * @cpu: cpu the idle task belongs to
5903 * NOTE: this function does not set the idle thread's NEED_RESCHED
5904 * flag, to make booting more robust.
5906 void __cpuinit init_idle(struct task_struct *idle, int cpu)
5908 struct rq *rq = cpu_rq(cpu);
5909 unsigned long flags;
5911 spin_lock_irqsave(&rq->lock, flags);
5914 idle->se.exec_start = sched_clock();
5916 idle->prio = idle->normal_prio = MAX_PRIO;
5917 idle->cpus_allowed = cpumask_of_cpu(cpu);
5918 __set_task_cpu(idle, cpu);
5920 rq->curr = rq->idle = idle;
5921 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
5924 spin_unlock_irqrestore(&rq->lock, flags);
5926 /* Set the preempt count _outside_ the spinlocks! */
5927 #if defined(CONFIG_PREEMPT)
5928 task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0);
5930 task_thread_info(idle)->preempt_count = 0;
5933 * The idle tasks have their own, simple scheduling class:
5935 idle->sched_class = &idle_sched_class;
5936 ftrace_graph_init_task(idle);
5940 * In a system that switches off the HZ timer nohz_cpu_mask
5941 * indicates which cpus entered this state. This is used
5942 * in the rcu update to wait only for active cpus. For system
5943 * which do not switch off the HZ timer nohz_cpu_mask should
5944 * always be CPU_MASK_NONE.
5946 cpumask_t nohz_cpu_mask = CPU_MASK_NONE;
5949 * Increase the granularity value when there are more CPUs,
5950 * because with more CPUs the 'effective latency' as visible
5951 * to users decreases. But the relationship is not linear,
5952 * so pick a second-best guess by going with the log2 of the
5955 * This idea comes from the SD scheduler of Con Kolivas:
5957 static inline void sched_init_granularity(void)
5959 unsigned int factor = 1 + ilog2(num_online_cpus());
5960 const unsigned long limit = 200000000;
5962 sysctl_sched_min_granularity *= factor;
5963 if (sysctl_sched_min_granularity > limit)
5964 sysctl_sched_min_granularity = limit;
5966 sysctl_sched_latency *= factor;
5967 if (sysctl_sched_latency > limit)
5968 sysctl_sched_latency = limit;
5970 sysctl_sched_wakeup_granularity *= factor;
5972 sysctl_sched_shares_ratelimit *= factor;
5977 * This is how migration works:
5979 * 1) we queue a struct migration_req structure in the source CPU's
5980 * runqueue and wake up that CPU's migration thread.
5981 * 2) we down() the locked semaphore => thread blocks.
5982 * 3) migration thread wakes up (implicitly it forces the migrated
5983 * thread off the CPU)
5984 * 4) it gets the migration request and checks whether the migrated
5985 * task is still in the wrong runqueue.
5986 * 5) if it's in the wrong runqueue then the migration thread removes
5987 * it and puts it into the right queue.
5988 * 6) migration thread up()s the semaphore.
5989 * 7) we wake up and the migration is done.
5993 * Change a given task's CPU affinity. Migrate the thread to a
5994 * proper CPU and schedule it away if the CPU it's executing on
5995 * is removed from the allowed bitmask.
5997 * NOTE: the caller must have a valid reference to the task, the
5998 * task must not exit() & deallocate itself prematurely. The
5999 * call is not atomic; no spinlocks may be held.
6001 int set_cpus_allowed_ptr(struct task_struct *p, const cpumask_t *new_mask)
6003 struct migration_req req;
6004 unsigned long flags;
6008 rq = task_rq_lock(p, &flags);
6009 if (!cpus_intersects(*new_mask, cpu_online_map)) {
6014 if (unlikely((p->flags & PF_THREAD_BOUND) && p != current &&
6015 !cpus_equal(p->cpus_allowed, *new_mask))) {
6020 if (p->sched_class->set_cpus_allowed)
6021 p->sched_class->set_cpus_allowed(p, new_mask);
6023 p->cpus_allowed = *new_mask;
6024 p->rt.nr_cpus_allowed = cpus_weight(*new_mask);
6027 /* Can the task run on the task's current CPU? If so, we're done */
6028 if (cpu_isset(task_cpu(p), *new_mask))
6031 if (migrate_task(p, any_online_cpu(*new_mask), &req)) {
6032 /* Need help from migration thread: drop lock and wait. */
6033 task_rq_unlock(rq, &flags);
6034 wake_up_process(rq->migration_thread);
6035 wait_for_completion(&req.done);
6036 tlb_migrate_finish(p->mm);
6040 task_rq_unlock(rq, &flags);
6044 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
6047 * Move (not current) task off this cpu, onto dest cpu. We're doing
6048 * this because either it can't run here any more (set_cpus_allowed()
6049 * away from this CPU, or CPU going down), or because we're
6050 * attempting to rebalance this task on exec (sched_exec).
6052 * So we race with normal scheduler movements, but that's OK, as long
6053 * as the task is no longer on this CPU.
6055 * Returns non-zero if task was successfully migrated.
6057 static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
6059 struct rq *rq_dest, *rq_src;
6062 if (unlikely(!cpu_active(dest_cpu)))
6065 rq_src = cpu_rq(src_cpu);
6066 rq_dest = cpu_rq(dest_cpu);
6068 double_rq_lock(rq_src, rq_dest);
6069 /* Already moved. */
6070 if (task_cpu(p) != src_cpu)
6072 /* Affinity changed (again). */
6073 if (!cpu_isset(dest_cpu, p->cpus_allowed))
6076 on_rq = p->se.on_rq;
6078 deactivate_task(rq_src, p, 0);
6080 set_task_cpu(p, dest_cpu);
6082 activate_task(rq_dest, p, 0);
6083 check_preempt_curr(rq_dest, p, 0);
6088 double_rq_unlock(rq_src, rq_dest);
6093 * migration_thread - this is a highprio system thread that performs
6094 * thread migration by bumping thread off CPU then 'pushing' onto
6097 static int migration_thread(void *data)
6099 int cpu = (long)data;
6103 BUG_ON(rq->migration_thread != current);
6105 set_current_state(TASK_INTERRUPTIBLE);
6106 while (!kthread_should_stop()) {
6107 struct migration_req *req;
6108 struct list_head *head;
6110 spin_lock_irq(&rq->lock);
6112 if (cpu_is_offline(cpu)) {
6113 spin_unlock_irq(&rq->lock);
6117 if (rq->active_balance) {
6118 active_load_balance(rq, cpu);
6119 rq->active_balance = 0;
6122 head = &rq->migration_queue;
6124 if (list_empty(head)) {
6125 spin_unlock_irq(&rq->lock);
6127 set_current_state(TASK_INTERRUPTIBLE);
6130 req = list_entry(head->next, struct migration_req, list);
6131 list_del_init(head->next);
6133 spin_unlock(&rq->lock);
6134 __migrate_task(req->task, cpu, req->dest_cpu);
6137 complete(&req->done);
6139 __set_current_state(TASK_RUNNING);
6143 /* Wait for kthread_stop */
6144 set_current_state(TASK_INTERRUPTIBLE);
6145 while (!kthread_should_stop()) {
6147 set_current_state(TASK_INTERRUPTIBLE);
6149 __set_current_state(TASK_RUNNING);
6153 #ifdef CONFIG_HOTPLUG_CPU
6155 static int __migrate_task_irq(struct task_struct *p, int src_cpu, int dest_cpu)
6159 local_irq_disable();
6160 ret = __migrate_task(p, src_cpu, dest_cpu);
6166 * Figure out where task on dead CPU should go, use force if necessary.
6168 static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p)
6170 unsigned long flags;
6177 mask = node_to_cpumask(cpu_to_node(dead_cpu));
6178 cpus_and(mask, mask, p->cpus_allowed);
6179 dest_cpu = any_online_cpu(mask);
6181 /* On any allowed CPU? */
6182 if (dest_cpu >= nr_cpu_ids)
6183 dest_cpu = any_online_cpu(p->cpus_allowed);
6185 /* No more Mr. Nice Guy. */
6186 if (dest_cpu >= nr_cpu_ids) {
6187 cpumask_t cpus_allowed;
6189 cpuset_cpus_allowed_locked(p, &cpus_allowed);
6191 * Try to stay on the same cpuset, where the
6192 * current cpuset may be a subset of all cpus.
6193 * The cpuset_cpus_allowed_locked() variant of
6194 * cpuset_cpus_allowed() will not block. It must be
6195 * called within calls to cpuset_lock/cpuset_unlock.
6197 rq = task_rq_lock(p, &flags);
6198 p->cpus_allowed = cpus_allowed;
6199 dest_cpu = any_online_cpu(p->cpus_allowed);
6200 task_rq_unlock(rq, &flags);
6203 * Don't tell them about moving exiting tasks or
6204 * kernel threads (both mm NULL), since they never
6207 if (p->mm && printk_ratelimit()) {
6208 printk(KERN_INFO "process %d (%s) no "
6209 "longer affine to cpu%d\n",
6210 task_pid_nr(p), p->comm, dead_cpu);
6213 } while (!__migrate_task_irq(p, dead_cpu, dest_cpu));
6217 * While a dead CPU has no uninterruptible tasks queued at this point,
6218 * it might still have a nonzero ->nr_uninterruptible counter, because
6219 * for performance reasons the counter is not stricly tracking tasks to
6220 * their home CPUs. So we just add the counter to another CPU's counter,
6221 * to keep the global sum constant after CPU-down:
6223 static void migrate_nr_uninterruptible(struct rq *rq_src)
6225 struct rq *rq_dest = cpu_rq(any_online_cpu(*CPU_MASK_ALL_PTR));
6226 unsigned long flags;
6228 local_irq_save(flags);
6229 double_rq_lock(rq_src, rq_dest);
6230 rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible;
6231 rq_src->nr_uninterruptible = 0;
6232 double_rq_unlock(rq_src, rq_dest);
6233 local_irq_restore(flags);
6236 /* Run through task list and migrate tasks from the dead cpu. */
6237 static void migrate_live_tasks(int src_cpu)
6239 struct task_struct *p, *t;
6241 read_lock(&tasklist_lock);
6243 do_each_thread(t, p) {
6247 if (task_cpu(p) == src_cpu)
6248 move_task_off_dead_cpu(src_cpu, p);
6249 } while_each_thread(t, p);
6251 read_unlock(&tasklist_lock);
6255 * Schedules idle task to be the next runnable task on current CPU.
6256 * It does so by boosting its priority to highest possible.
6257 * Used by CPU offline code.
6259 void sched_idle_next(void)
6261 int this_cpu = smp_processor_id();
6262 struct rq *rq = cpu_rq(this_cpu);
6263 struct task_struct *p = rq->idle;
6264 unsigned long flags;
6266 /* cpu has to be offline */
6267 BUG_ON(cpu_online(this_cpu));
6270 * Strictly not necessary since rest of the CPUs are stopped by now
6271 * and interrupts disabled on the current cpu.
6273 spin_lock_irqsave(&rq->lock, flags);
6275 __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
6277 update_rq_clock(rq);
6278 activate_task(rq, p, 0);
6280 spin_unlock_irqrestore(&rq->lock, flags);
6284 * Ensures that the idle task is using init_mm right before its cpu goes
6287 void idle_task_exit(void)
6289 struct mm_struct *mm = current->active_mm;
6291 BUG_ON(cpu_online(smp_processor_id()));
6294 switch_mm(mm, &init_mm, current);
6298 /* called under rq->lock with disabled interrupts */
6299 static void migrate_dead(unsigned int dead_cpu, struct task_struct *p)
6301 struct rq *rq = cpu_rq(dead_cpu);
6303 /* Must be exiting, otherwise would be on tasklist. */
6304 BUG_ON(!p->exit_state);
6306 /* Cannot have done final schedule yet: would have vanished. */
6307 BUG_ON(p->state == TASK_DEAD);
6312 * Drop lock around migration; if someone else moves it,
6313 * that's OK. No task can be added to this CPU, so iteration is
6316 spin_unlock_irq(&rq->lock);
6317 move_task_off_dead_cpu(dead_cpu, p);
6318 spin_lock_irq(&rq->lock);
6323 /* release_task() removes task from tasklist, so we won't find dead tasks. */
6324 static void migrate_dead_tasks(unsigned int dead_cpu)
6326 struct rq *rq = cpu_rq(dead_cpu);
6327 struct task_struct *next;
6330 if (!rq->nr_running)
6332 update_rq_clock(rq);
6333 next = pick_next_task(rq, rq->curr);
6336 next->sched_class->put_prev_task(rq, next);
6337 migrate_dead(dead_cpu, next);
6341 #endif /* CONFIG_HOTPLUG_CPU */
6343 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
6345 static struct ctl_table sd_ctl_dir[] = {
6347 .procname = "sched_domain",
6353 static struct ctl_table sd_ctl_root[] = {
6355 .ctl_name = CTL_KERN,
6356 .procname = "kernel",
6358 .child = sd_ctl_dir,
6363 static struct ctl_table *sd_alloc_ctl_entry(int n)
6365 struct ctl_table *entry =
6366 kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL);
6371 static void sd_free_ctl_entry(struct ctl_table **tablep)
6373 struct ctl_table *entry;
6376 * In the intermediate directories, both the child directory and
6377 * procname are dynamically allocated and could fail but the mode
6378 * will always be set. In the lowest directory the names are
6379 * static strings and all have proc handlers.
6381 for (entry = *tablep; entry->mode; entry++) {
6383 sd_free_ctl_entry(&entry->child);
6384 if (entry->proc_handler == NULL)
6385 kfree(entry->procname);
6393 set_table_entry(struct ctl_table *entry,
6394 const char *procname, void *data, int maxlen,
6395 mode_t mode, proc_handler *proc_handler)
6397 entry->procname = procname;
6399 entry->maxlen = maxlen;
6401 entry->proc_handler = proc_handler;
6404 static struct ctl_table *
6405 sd_alloc_ctl_domain_table(struct sched_domain *sd)
6407 struct ctl_table *table = sd_alloc_ctl_entry(13);
6412 set_table_entry(&table[0], "min_interval", &sd->min_interval,
6413 sizeof(long), 0644, proc_doulongvec_minmax);
6414 set_table_entry(&table[1], "max_interval", &sd->max_interval,
6415 sizeof(long), 0644, proc_doulongvec_minmax);
6416 set_table_entry(&table[2], "busy_idx", &sd->busy_idx,
6417 sizeof(int), 0644, proc_dointvec_minmax);
6418 set_table_entry(&table[3], "idle_idx", &sd->idle_idx,
6419 sizeof(int), 0644, proc_dointvec_minmax);
6420 set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx,
6421 sizeof(int), 0644, proc_dointvec_minmax);
6422 set_table_entry(&table[5], "wake_idx", &sd->wake_idx,
6423 sizeof(int), 0644, proc_dointvec_minmax);
6424 set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx,
6425 sizeof(int), 0644, proc_dointvec_minmax);
6426 set_table_entry(&table[7], "busy_factor", &sd->busy_factor,
6427 sizeof(int), 0644, proc_dointvec_minmax);
6428 set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct,
6429 sizeof(int), 0644, proc_dointvec_minmax);
6430 set_table_entry(&table[9], "cache_nice_tries",
6431 &sd->cache_nice_tries,
6432 sizeof(int), 0644, proc_dointvec_minmax);
6433 set_table_entry(&table[10], "flags", &sd->flags,
6434 sizeof(int), 0644, proc_dointvec_minmax);
6435 set_table_entry(&table[11], "name", sd->name,
6436 CORENAME_MAX_SIZE, 0444, proc_dostring);
6437 /* &table[12] is terminator */
6442 static ctl_table *sd_alloc_ctl_cpu_table(int cpu)
6444 struct ctl_table *entry, *table;
6445 struct sched_domain *sd;
6446 int domain_num = 0, i;
6449 for_each_domain(cpu, sd)
6451 entry = table = sd_alloc_ctl_entry(domain_num + 1);
6456 for_each_domain(cpu, sd) {
6457 snprintf(buf, 32, "domain%d", i);
6458 entry->procname = kstrdup(buf, GFP_KERNEL);
6460 entry->child = sd_alloc_ctl_domain_table(sd);
6467 static struct ctl_table_header *sd_sysctl_header;
6468 static void register_sched_domain_sysctl(void)
6470 int i, cpu_num = num_online_cpus();
6471 struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1);
6474 WARN_ON(sd_ctl_dir[0].child);
6475 sd_ctl_dir[0].child = entry;
6480 for_each_online_cpu(i) {
6481 snprintf(buf, 32, "cpu%d", i);
6482 entry->procname = kstrdup(buf, GFP_KERNEL);
6484 entry->child = sd_alloc_ctl_cpu_table(i);
6488 WARN_ON(sd_sysctl_header);
6489 sd_sysctl_header = register_sysctl_table(sd_ctl_root);
6492 /* may be called multiple times per register */
6493 static void unregister_sched_domain_sysctl(void)
6495 if (sd_sysctl_header)
6496 unregister_sysctl_table(sd_sysctl_header);
6497 sd_sysctl_header = NULL;
6498 if (sd_ctl_dir[0].child)
6499 sd_free_ctl_entry(&sd_ctl_dir[0].child);
6502 static void register_sched_domain_sysctl(void)
6505 static void unregister_sched_domain_sysctl(void)
6510 static void set_rq_online(struct rq *rq)
6513 const struct sched_class *class;
6515 cpu_set(rq->cpu, rq->rd->online);
6518 for_each_class(class) {
6519 if (class->rq_online)
6520 class->rq_online(rq);
6525 static void set_rq_offline(struct rq *rq)
6528 const struct sched_class *class;
6530 for_each_class(class) {
6531 if (class->rq_offline)
6532 class->rq_offline(rq);
6535 cpu_clear(rq->cpu, rq->rd->online);
6541 * migration_call - callback that gets triggered when a CPU is added.
6542 * Here we can start up the necessary migration thread for the new CPU.
6544 static int __cpuinit
6545 migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
6547 struct task_struct *p;
6548 int cpu = (long)hcpu;
6549 unsigned long flags;
6554 case CPU_UP_PREPARE:
6555 case CPU_UP_PREPARE_FROZEN:
6556 p = kthread_create(migration_thread, hcpu, "migration/%d", cpu);
6559 kthread_bind(p, cpu);
6560 /* Must be high prio: stop_machine expects to yield to it. */
6561 rq = task_rq_lock(p, &flags);
6562 __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
6563 task_rq_unlock(rq, &flags);
6564 cpu_rq(cpu)->migration_thread = p;
6568 case CPU_ONLINE_FROZEN:
6569 /* Strictly unnecessary, as first user will wake it. */
6570 wake_up_process(cpu_rq(cpu)->migration_thread);
6572 /* Update our root-domain */
6574 spin_lock_irqsave(&rq->lock, flags);
6576 BUG_ON(!cpu_isset(cpu, rq->rd->span));
6580 spin_unlock_irqrestore(&rq->lock, flags);
6583 #ifdef CONFIG_HOTPLUG_CPU
6584 case CPU_UP_CANCELED:
6585 case CPU_UP_CANCELED_FROZEN:
6586 if (!cpu_rq(cpu)->migration_thread)
6588 /* Unbind it from offline cpu so it can run. Fall thru. */
6589 kthread_bind(cpu_rq(cpu)->migration_thread,
6590 any_online_cpu(cpu_online_map));
6591 kthread_stop(cpu_rq(cpu)->migration_thread);
6592 cpu_rq(cpu)->migration_thread = NULL;
6596 case CPU_DEAD_FROZEN:
6597 cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */
6598 migrate_live_tasks(cpu);
6600 kthread_stop(rq->migration_thread);
6601 rq->migration_thread = NULL;
6602 /* Idle task back to normal (off runqueue, low prio) */
6603 spin_lock_irq(&rq->lock);
6604 update_rq_clock(rq);
6605 deactivate_task(rq, rq->idle, 0);
6606 rq->idle->static_prio = MAX_PRIO;
6607 __setscheduler(rq, rq->idle, SCHED_NORMAL, 0);
6608 rq->idle->sched_class = &idle_sched_class;
6609 migrate_dead_tasks(cpu);
6610 spin_unlock_irq(&rq->lock);
6612 migrate_nr_uninterruptible(rq);
6613 BUG_ON(rq->nr_running != 0);
6616 * No need to migrate the tasks: it was best-effort if
6617 * they didn't take sched_hotcpu_mutex. Just wake up
6620 spin_lock_irq(&rq->lock);
6621 while (!list_empty(&rq->migration_queue)) {
6622 struct migration_req *req;
6624 req = list_entry(rq->migration_queue.next,
6625 struct migration_req, list);
6626 list_del_init(&req->list);
6627 spin_unlock_irq(&rq->lock);
6628 complete(&req->done);
6629 spin_lock_irq(&rq->lock);
6631 spin_unlock_irq(&rq->lock);
6635 case CPU_DYING_FROZEN:
6636 /* Update our root-domain */
6638 spin_lock_irqsave(&rq->lock, flags);
6640 BUG_ON(!cpu_isset(cpu, rq->rd->span));
6643 spin_unlock_irqrestore(&rq->lock, flags);
6650 /* Register at highest priority so that task migration (migrate_all_tasks)
6651 * happens before everything else.
6653 static struct notifier_block __cpuinitdata migration_notifier = {
6654 .notifier_call = migration_call,
6658 static int __init migration_init(void)
6660 void *cpu = (void *)(long)smp_processor_id();
6663 /* Start one for the boot CPU: */
6664 err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
6665 BUG_ON(err == NOTIFY_BAD);
6666 migration_call(&migration_notifier, CPU_ONLINE, cpu);
6667 register_cpu_notifier(&migration_notifier);
6671 early_initcall(migration_init);
6676 #ifdef CONFIG_SCHED_DEBUG
6678 static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
6679 cpumask_t *groupmask)
6681 struct sched_group *group = sd->groups;
6684 cpulist_scnprintf(str, sizeof(str), sd->span);
6685 cpus_clear(*groupmask);
6687 printk(KERN_DEBUG "%*s domain %d: ", level, "", level);
6689 if (!(sd->flags & SD_LOAD_BALANCE)) {
6690 printk("does not load-balance\n");
6692 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain"
6697 printk(KERN_CONT "span %s level %s\n", str, sd->name);
6699 if (!cpu_isset(cpu, sd->span)) {
6700 printk(KERN_ERR "ERROR: domain->span does not contain "
6703 if (!cpu_isset(cpu, group->cpumask)) {
6704 printk(KERN_ERR "ERROR: domain->groups does not contain"
6708 printk(KERN_DEBUG "%*s groups:", level + 1, "");
6712 printk(KERN_ERR "ERROR: group is NULL\n");
6716 if (!group->__cpu_power) {
6717 printk(KERN_CONT "\n");
6718 printk(KERN_ERR "ERROR: domain->cpu_power not "
6723 if (!cpus_weight(group->cpumask)) {
6724 printk(KERN_CONT "\n");
6725 printk(KERN_ERR "ERROR: empty group\n");
6729 if (cpus_intersects(*groupmask, group->cpumask)) {
6730 printk(KERN_CONT "\n");
6731 printk(KERN_ERR "ERROR: repeated CPUs\n");
6735 cpus_or(*groupmask, *groupmask, group->cpumask);
6737 cpulist_scnprintf(str, sizeof(str), group->cpumask);
6738 printk(KERN_CONT " %s", str);
6740 group = group->next;
6741 } while (group != sd->groups);
6742 printk(KERN_CONT "\n");
6744 if (!cpus_equal(sd->span, *groupmask))
6745 printk(KERN_ERR "ERROR: groups don't span domain->span\n");
6747 if (sd->parent && !cpus_subset(*groupmask, sd->parent->span))
6748 printk(KERN_ERR "ERROR: parent span is not a superset "
6749 "of domain->span\n");
6753 static void sched_domain_debug(struct sched_domain *sd, int cpu)
6755 cpumask_t *groupmask;
6759 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
6763 printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu);
6765 groupmask = kmalloc(sizeof(cpumask_t), GFP_KERNEL);
6767 printk(KERN_DEBUG "Cannot load-balance (out of memory)\n");
6772 if (sched_domain_debug_one(sd, cpu, level, groupmask))
6781 #else /* !CONFIG_SCHED_DEBUG */
6782 # define sched_domain_debug(sd, cpu) do { } while (0)
6783 #endif /* CONFIG_SCHED_DEBUG */
6785 static int sd_degenerate(struct sched_domain *sd)
6787 if (cpus_weight(sd->span) == 1)
6790 /* Following flags need at least 2 groups */
6791 if (sd->flags & (SD_LOAD_BALANCE |
6792 SD_BALANCE_NEWIDLE |
6796 SD_SHARE_PKG_RESOURCES)) {
6797 if (sd->groups != sd->groups->next)
6801 /* Following flags don't use groups */
6802 if (sd->flags & (SD_WAKE_IDLE |
6811 sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
6813 unsigned long cflags = sd->flags, pflags = parent->flags;
6815 if (sd_degenerate(parent))
6818 if (!cpus_equal(sd->span, parent->span))
6821 /* Does parent contain flags not in child? */
6822 /* WAKE_BALANCE is a subset of WAKE_AFFINE */
6823 if (cflags & SD_WAKE_AFFINE)
6824 pflags &= ~SD_WAKE_BALANCE;
6825 /* Flags needing groups don't count if only 1 group in parent */
6826 if (parent->groups == parent->groups->next) {
6827 pflags &= ~(SD_LOAD_BALANCE |
6828 SD_BALANCE_NEWIDLE |
6832 SD_SHARE_PKG_RESOURCES);
6833 if (nr_node_ids == 1)
6834 pflags &= ~SD_SERIALIZE;
6836 if (~cflags & pflags)
6842 static void rq_attach_root(struct rq *rq, struct root_domain *rd)
6844 unsigned long flags;
6846 spin_lock_irqsave(&rq->lock, flags);
6849 struct root_domain *old_rd = rq->rd;
6851 if (cpu_isset(rq->cpu, old_rd->online))
6854 cpu_clear(rq->cpu, old_rd->span);
6856 if (atomic_dec_and_test(&old_rd->refcount))
6860 atomic_inc(&rd->refcount);
6863 cpu_set(rq->cpu, rd->span);
6864 if (cpu_isset(rq->cpu, cpu_online_map))
6867 spin_unlock_irqrestore(&rq->lock, flags);
6870 static void init_rootdomain(struct root_domain *rd)
6872 memset(rd, 0, sizeof(*rd));
6874 cpus_clear(rd->span);
6875 cpus_clear(rd->online);
6877 cpupri_init(&rd->cpupri);
6880 static void init_defrootdomain(void)
6882 init_rootdomain(&def_root_domain);
6883 atomic_set(&def_root_domain.refcount, 1);
6886 static struct root_domain *alloc_rootdomain(void)
6888 struct root_domain *rd;
6890 rd = kmalloc(sizeof(*rd), GFP_KERNEL);
6894 init_rootdomain(rd);
6900 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
6901 * hold the hotplug lock.
6904 cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
6906 struct rq *rq = cpu_rq(cpu);
6907 struct sched_domain *tmp;
6909 /* Remove the sched domains which do not contribute to scheduling. */
6910 for (tmp = sd; tmp; ) {
6911 struct sched_domain *parent = tmp->parent;
6915 if (sd_parent_degenerate(tmp, parent)) {
6916 tmp->parent = parent->parent;
6918 parent->parent->child = tmp;
6923 if (sd && sd_degenerate(sd)) {
6929 sched_domain_debug(sd, cpu);
6931 rq_attach_root(rq, rd);
6932 rcu_assign_pointer(rq->sd, sd);
6935 /* cpus with isolated domains */
6936 static cpumask_t cpu_isolated_map = CPU_MASK_NONE;
6938 /* Setup the mask of cpus configured for isolated domains */
6939 static int __init isolated_cpu_setup(char *str)
6941 static int __initdata ints[NR_CPUS];
6944 str = get_options(str, ARRAY_SIZE(ints), ints);
6945 cpus_clear(cpu_isolated_map);
6946 for (i = 1; i <= ints[0]; i++)
6947 if (ints[i] < NR_CPUS)
6948 cpu_set(ints[i], cpu_isolated_map);
6952 __setup("isolcpus=", isolated_cpu_setup);
6955 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
6956 * to a function which identifies what group(along with sched group) a CPU
6957 * belongs to. The return value of group_fn must be a >= 0 and < NR_CPUS
6958 * (due to the fact that we keep track of groups covered with a cpumask_t).
6960 * init_sched_build_groups will build a circular linked list of the groups
6961 * covered by the given span, and will set each group's ->cpumask correctly,
6962 * and ->cpu_power to 0.
6965 init_sched_build_groups(const cpumask_t *span, const cpumask_t *cpu_map,
6966 int (*group_fn)(int cpu, const cpumask_t *cpu_map,
6967 struct sched_group **sg,
6968 cpumask_t *tmpmask),
6969 cpumask_t *covered, cpumask_t *tmpmask)
6971 struct sched_group *first = NULL, *last = NULL;
6974 cpus_clear(*covered);
6976 for_each_cpu_mask_nr(i, *span) {
6977 struct sched_group *sg;
6978 int group = group_fn(i, cpu_map, &sg, tmpmask);
6981 if (cpu_isset(i, *covered))
6984 cpus_clear(sg->cpumask);
6985 sg->__cpu_power = 0;
6987 for_each_cpu_mask_nr(j, *span) {
6988 if (group_fn(j, cpu_map, NULL, tmpmask) != group)
6991 cpu_set(j, *covered);
6992 cpu_set(j, sg->cpumask);
7003 #define SD_NODES_PER_DOMAIN 16
7008 * find_next_best_node - find the next node to include in a sched_domain
7009 * @node: node whose sched_domain we're building
7010 * @used_nodes: nodes already in the sched_domain
7012 * Find the next node to include in a given scheduling domain. Simply
7013 * finds the closest node not already in the @used_nodes map.
7015 * Should use nodemask_t.
7017 static int find_next_best_node(int node, nodemask_t *used_nodes)
7019 int i, n, val, min_val, best_node = 0;
7023 for (i = 0; i < nr_node_ids; i++) {
7024 /* Start at @node */
7025 n = (node + i) % nr_node_ids;
7027 if (!nr_cpus_node(n))
7030 /* Skip already used nodes */
7031 if (node_isset(n, *used_nodes))
7034 /* Simple min distance search */
7035 val = node_distance(node, n);
7037 if (val < min_val) {
7043 node_set(best_node, *used_nodes);
7048 * sched_domain_node_span - get a cpumask for a node's sched_domain
7049 * @node: node whose cpumask we're constructing
7050 * @span: resulting cpumask
7052 * Given a node, construct a good cpumask for its sched_domain to span. It
7053 * should be one that prevents unnecessary balancing, but also spreads tasks
7056 static void sched_domain_node_span(int node, cpumask_t *span)
7058 nodemask_t used_nodes;
7059 node_to_cpumask_ptr(nodemask, node);
7063 nodes_clear(used_nodes);
7065 cpus_or(*span, *span, *nodemask);
7066 node_set(node, used_nodes);
7068 for (i = 1; i < SD_NODES_PER_DOMAIN; i++) {
7069 int next_node = find_next_best_node(node, &used_nodes);
7071 node_to_cpumask_ptr_next(nodemask, next_node);
7072 cpus_or(*span, *span, *nodemask);
7075 #endif /* CONFIG_NUMA */
7077 int sched_smt_power_savings = 0, sched_mc_power_savings = 0;
7080 * SMT sched-domains:
7082 #ifdef CONFIG_SCHED_SMT
7083 static DEFINE_PER_CPU(struct sched_domain, cpu_domains);
7084 static DEFINE_PER_CPU(struct sched_group, sched_group_cpus);
7087 cpu_to_cpu_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg,
7091 *sg = &per_cpu(sched_group_cpus, cpu);
7094 #endif /* CONFIG_SCHED_SMT */
7097 * multi-core sched-domains:
7099 #ifdef CONFIG_SCHED_MC
7100 static DEFINE_PER_CPU(struct sched_domain, core_domains);
7101 static DEFINE_PER_CPU(struct sched_group, sched_group_core);
7102 #endif /* CONFIG_SCHED_MC */
7104 #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
7106 cpu_to_core_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg,
7111 *mask = per_cpu(cpu_sibling_map, cpu);
7112 cpus_and(*mask, *mask, *cpu_map);
7113 group = first_cpu(*mask);
7115 *sg = &per_cpu(sched_group_core, group);
7118 #elif defined(CONFIG_SCHED_MC)
7120 cpu_to_core_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg,
7124 *sg = &per_cpu(sched_group_core, cpu);
7129 static DEFINE_PER_CPU(struct sched_domain, phys_domains);
7130 static DEFINE_PER_CPU(struct sched_group, sched_group_phys);
7133 cpu_to_phys_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg,
7137 #ifdef CONFIG_SCHED_MC
7138 *mask = cpu_coregroup_map(cpu);
7139 cpus_and(*mask, *mask, *cpu_map);
7140 group = first_cpu(*mask);
7141 #elif defined(CONFIG_SCHED_SMT)
7142 *mask = per_cpu(cpu_sibling_map, cpu);
7143 cpus_and(*mask, *mask, *cpu_map);
7144 group = first_cpu(*mask);
7149 *sg = &per_cpu(sched_group_phys, group);
7155 * The init_sched_build_groups can't handle what we want to do with node
7156 * groups, so roll our own. Now each node has its own list of groups which
7157 * gets dynamically allocated.
7159 static DEFINE_PER_CPU(struct sched_domain, node_domains);
7160 static struct sched_group ***sched_group_nodes_bycpu;
7162 static DEFINE_PER_CPU(struct sched_domain, allnodes_domains);
7163 static DEFINE_PER_CPU(struct sched_group, sched_group_allnodes);
7165 static int cpu_to_allnodes_group(int cpu, const cpumask_t *cpu_map,
7166 struct sched_group **sg, cpumask_t *nodemask)
7170 *nodemask = node_to_cpumask(cpu_to_node(cpu));
7171 cpus_and(*nodemask, *nodemask, *cpu_map);
7172 group = first_cpu(*nodemask);
7175 *sg = &per_cpu(sched_group_allnodes, group);
7179 static void init_numa_sched_groups_power(struct sched_group *group_head)
7181 struct sched_group *sg = group_head;
7187 for_each_cpu_mask_nr(j, sg->cpumask) {
7188 struct sched_domain *sd;
7190 sd = &per_cpu(phys_domains, j);
7191 if (j != first_cpu(sd->groups->cpumask)) {
7193 * Only add "power" once for each
7199 sg_inc_cpu_power(sg, sd->groups->__cpu_power);
7202 } while (sg != group_head);
7204 #endif /* CONFIG_NUMA */
7207 /* Free memory allocated for various sched_group structures */
7208 static void free_sched_groups(const cpumask_t *cpu_map, cpumask_t *nodemask)
7212 for_each_cpu_mask_nr(cpu, *cpu_map) {
7213 struct sched_group **sched_group_nodes
7214 = sched_group_nodes_bycpu[cpu];
7216 if (!sched_group_nodes)
7219 for (i = 0; i < nr_node_ids; i++) {
7220 struct sched_group *oldsg, *sg = sched_group_nodes[i];
7222 *nodemask = node_to_cpumask(i);
7223 cpus_and(*nodemask, *nodemask, *cpu_map);
7224 if (cpus_empty(*nodemask))
7234 if (oldsg != sched_group_nodes[i])
7237 kfree(sched_group_nodes);
7238 sched_group_nodes_bycpu[cpu] = NULL;
7241 #else /* !CONFIG_NUMA */
7242 static void free_sched_groups(const cpumask_t *cpu_map, cpumask_t *nodemask)
7245 #endif /* CONFIG_NUMA */
7248 * Initialize sched groups cpu_power.
7250 * cpu_power indicates the capacity of sched group, which is used while
7251 * distributing the load between different sched groups in a sched domain.
7252 * Typically cpu_power for all the groups in a sched domain will be same unless
7253 * there are asymmetries in the topology. If there are asymmetries, group
7254 * having more cpu_power will pickup more load compared to the group having
7257 * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents
7258 * the maximum number of tasks a group can handle in the presence of other idle
7259 * or lightly loaded groups in the same sched domain.
7261 static void init_sched_groups_power(int cpu, struct sched_domain *sd)
7263 struct sched_domain *child;
7264 struct sched_group *group;
7266 WARN_ON(!sd || !sd->groups);
7268 if (cpu != first_cpu(sd->groups->cpumask))
7273 sd->groups->__cpu_power = 0;
7276 * For perf policy, if the groups in child domain share resources
7277 * (for example cores sharing some portions of the cache hierarchy
7278 * or SMT), then set this domain groups cpu_power such that each group
7279 * can handle only one task, when there are other idle groups in the
7280 * same sched domain.
7282 if (!child || (!(sd->flags & SD_POWERSAVINGS_BALANCE) &&
7284 (SD_SHARE_CPUPOWER | SD_SHARE_PKG_RESOURCES)))) {
7285 sg_inc_cpu_power(sd->groups, SCHED_LOAD_SCALE);
7290 * add cpu_power of each child group to this groups cpu_power
7292 group = child->groups;
7294 sg_inc_cpu_power(sd->groups, group->__cpu_power);
7295 group = group->next;
7296 } while (group != child->groups);
7300 * Initializers for schedule domains
7301 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
7304 #ifdef CONFIG_SCHED_DEBUG
7305 # define SD_INIT_NAME(sd, type) sd->name = #type
7307 # define SD_INIT_NAME(sd, type) do { } while (0)
7310 #define SD_INIT(sd, type) sd_init_##type(sd)
7312 #define SD_INIT_FUNC(type) \
7313 static noinline void sd_init_##type(struct sched_domain *sd) \
7315 memset(sd, 0, sizeof(*sd)); \
7316 *sd = SD_##type##_INIT; \
7317 sd->level = SD_LV_##type; \
7318 SD_INIT_NAME(sd, type); \
7323 SD_INIT_FUNC(ALLNODES)
7326 #ifdef CONFIG_SCHED_SMT
7327 SD_INIT_FUNC(SIBLING)
7329 #ifdef CONFIG_SCHED_MC
7334 * To minimize stack usage kmalloc room for cpumasks and share the
7335 * space as the usage in build_sched_domains() dictates. Used only
7336 * if the amount of space is significant.
7339 cpumask_t tmpmask; /* make this one first */
7342 cpumask_t this_sibling_map;
7343 cpumask_t this_core_map;
7345 cpumask_t send_covered;
7348 cpumask_t domainspan;
7350 cpumask_t notcovered;
7355 #define SCHED_CPUMASK_DECLARE(v) struct allmasks *v
7356 static inline void sched_cpumask_alloc(struct allmasks **masks)
7358 *masks = kmalloc(sizeof(**masks), GFP_KERNEL);
7360 static inline void sched_cpumask_free(struct allmasks *masks)
7365 #define SCHED_CPUMASK_DECLARE(v) struct allmasks _v, *v = &_v
7366 static inline void sched_cpumask_alloc(struct allmasks **masks)
7368 static inline void sched_cpumask_free(struct allmasks *masks)
7372 #define SCHED_CPUMASK_VAR(v, a) cpumask_t *v = (cpumask_t *) \
7373 ((unsigned long)(a) + offsetof(struct allmasks, v))
7375 static int default_relax_domain_level = -1;
7377 static int __init setup_relax_domain_level(char *str)
7381 val = simple_strtoul(str, NULL, 0);
7382 if (val < SD_LV_MAX)
7383 default_relax_domain_level = val;
7387 __setup("relax_domain_level=", setup_relax_domain_level);
7389 static void set_domain_attribute(struct sched_domain *sd,
7390 struct sched_domain_attr *attr)
7394 if (!attr || attr->relax_domain_level < 0) {
7395 if (default_relax_domain_level < 0)
7398 request = default_relax_domain_level;
7400 request = attr->relax_domain_level;
7401 if (request < sd->level) {
7402 /* turn off idle balance on this domain */
7403 sd->flags &= ~(SD_WAKE_IDLE|SD_BALANCE_NEWIDLE);
7405 /* turn on idle balance on this domain */
7406 sd->flags |= (SD_WAKE_IDLE_FAR|SD_BALANCE_NEWIDLE);
7411 * Build sched domains for a given set of cpus and attach the sched domains
7412 * to the individual cpus
7414 static int __build_sched_domains(const cpumask_t *cpu_map,
7415 struct sched_domain_attr *attr)
7418 struct root_domain *rd;
7419 SCHED_CPUMASK_DECLARE(allmasks);
7422 struct sched_group **sched_group_nodes = NULL;
7423 int sd_allnodes = 0;
7426 * Allocate the per-node list of sched groups
7428 sched_group_nodes = kcalloc(nr_node_ids, sizeof(struct sched_group *),
7430 if (!sched_group_nodes) {
7431 printk(KERN_WARNING "Can not alloc sched group node list\n");
7436 rd = alloc_rootdomain();
7438 printk(KERN_WARNING "Cannot alloc root domain\n");
7440 kfree(sched_group_nodes);
7445 /* get space for all scratch cpumask variables */
7446 sched_cpumask_alloc(&allmasks);
7448 printk(KERN_WARNING "Cannot alloc cpumask array\n");
7451 kfree(sched_group_nodes);
7456 tmpmask = (cpumask_t *)allmasks;
7460 sched_group_nodes_bycpu[first_cpu(*cpu_map)] = sched_group_nodes;
7464 * Set up domains for cpus specified by the cpu_map.
7466 for_each_cpu_mask_nr(i, *cpu_map) {
7467 struct sched_domain *sd = NULL, *p;
7468 SCHED_CPUMASK_VAR(nodemask, allmasks);
7470 *nodemask = node_to_cpumask(cpu_to_node(i));
7471 cpus_and(*nodemask, *nodemask, *cpu_map);
7474 if (cpus_weight(*cpu_map) >
7475 SD_NODES_PER_DOMAIN*cpus_weight(*nodemask)) {
7476 sd = &per_cpu(allnodes_domains, i);
7477 SD_INIT(sd, ALLNODES);
7478 set_domain_attribute(sd, attr);
7479 sd->span = *cpu_map;
7480 cpu_to_allnodes_group(i, cpu_map, &sd->groups, tmpmask);
7486 sd = &per_cpu(node_domains, i);
7488 set_domain_attribute(sd, attr);
7489 sched_domain_node_span(cpu_to_node(i), &sd->span);
7493 cpus_and(sd->span, sd->span, *cpu_map);
7497 sd = &per_cpu(phys_domains, i);
7499 set_domain_attribute(sd, attr);
7500 sd->span = *nodemask;
7504 cpu_to_phys_group(i, cpu_map, &sd->groups, tmpmask);
7506 #ifdef CONFIG_SCHED_MC
7508 sd = &per_cpu(core_domains, i);
7510 set_domain_attribute(sd, attr);
7511 sd->span = cpu_coregroup_map(i);
7512 cpus_and(sd->span, sd->span, *cpu_map);
7515 cpu_to_core_group(i, cpu_map, &sd->groups, tmpmask);
7518 #ifdef CONFIG_SCHED_SMT
7520 sd = &per_cpu(cpu_domains, i);
7521 SD_INIT(sd, SIBLING);
7522 set_domain_attribute(sd, attr);
7523 sd->span = per_cpu(cpu_sibling_map, i);
7524 cpus_and(sd->span, sd->span, *cpu_map);
7527 cpu_to_cpu_group(i, cpu_map, &sd->groups, tmpmask);
7531 #ifdef CONFIG_SCHED_SMT
7532 /* Set up CPU (sibling) groups */
7533 for_each_cpu_mask_nr(i, *cpu_map) {
7534 SCHED_CPUMASK_VAR(this_sibling_map, allmasks);
7535 SCHED_CPUMASK_VAR(send_covered, allmasks);
7537 *this_sibling_map = per_cpu(cpu_sibling_map, i);
7538 cpus_and(*this_sibling_map, *this_sibling_map, *cpu_map);
7539 if (i != first_cpu(*this_sibling_map))
7542 init_sched_build_groups(this_sibling_map, cpu_map,
7544 send_covered, tmpmask);
7548 #ifdef CONFIG_SCHED_MC
7549 /* Set up multi-core groups */
7550 for_each_cpu_mask_nr(i, *cpu_map) {
7551 SCHED_CPUMASK_VAR(this_core_map, allmasks);
7552 SCHED_CPUMASK_VAR(send_covered, allmasks);
7554 *this_core_map = cpu_coregroup_map(i);
7555 cpus_and(*this_core_map, *this_core_map, *cpu_map);
7556 if (i != first_cpu(*this_core_map))
7559 init_sched_build_groups(this_core_map, cpu_map,
7561 send_covered, tmpmask);
7565 /* Set up physical groups */
7566 for (i = 0; i < nr_node_ids; i++) {
7567 SCHED_CPUMASK_VAR(nodemask, allmasks);
7568 SCHED_CPUMASK_VAR(send_covered, allmasks);
7570 *nodemask = node_to_cpumask(i);
7571 cpus_and(*nodemask, *nodemask, *cpu_map);
7572 if (cpus_empty(*nodemask))
7575 init_sched_build_groups(nodemask, cpu_map,
7577 send_covered, tmpmask);
7581 /* Set up node groups */
7583 SCHED_CPUMASK_VAR(send_covered, allmasks);
7585 init_sched_build_groups(cpu_map, cpu_map,
7586 &cpu_to_allnodes_group,
7587 send_covered, tmpmask);
7590 for (i = 0; i < nr_node_ids; i++) {
7591 /* Set up node groups */
7592 struct sched_group *sg, *prev;
7593 SCHED_CPUMASK_VAR(nodemask, allmasks);
7594 SCHED_CPUMASK_VAR(domainspan, allmasks);
7595 SCHED_CPUMASK_VAR(covered, allmasks);
7598 *nodemask = node_to_cpumask(i);
7599 cpus_clear(*covered);
7601 cpus_and(*nodemask, *nodemask, *cpu_map);
7602 if (cpus_empty(*nodemask)) {
7603 sched_group_nodes[i] = NULL;
7607 sched_domain_node_span(i, domainspan);
7608 cpus_and(*domainspan, *domainspan, *cpu_map);
7610 sg = kmalloc_node(sizeof(struct sched_group), GFP_KERNEL, i);
7612 printk(KERN_WARNING "Can not alloc domain group for "
7616 sched_group_nodes[i] = sg;
7617 for_each_cpu_mask_nr(j, *nodemask) {
7618 struct sched_domain *sd;
7620 sd = &per_cpu(node_domains, j);
7623 sg->__cpu_power = 0;
7624 sg->cpumask = *nodemask;
7626 cpus_or(*covered, *covered, *nodemask);
7629 for (j = 0; j < nr_node_ids; j++) {
7630 SCHED_CPUMASK_VAR(notcovered, allmasks);
7631 int n = (i + j) % nr_node_ids;
7632 node_to_cpumask_ptr(pnodemask, n);
7634 cpus_complement(*notcovered, *covered);
7635 cpus_and(*tmpmask, *notcovered, *cpu_map);
7636 cpus_and(*tmpmask, *tmpmask, *domainspan);
7637 if (cpus_empty(*tmpmask))
7640 cpus_and(*tmpmask, *tmpmask, *pnodemask);
7641 if (cpus_empty(*tmpmask))
7644 sg = kmalloc_node(sizeof(struct sched_group),
7648 "Can not alloc domain group for node %d\n", j);
7651 sg->__cpu_power = 0;
7652 sg->cpumask = *tmpmask;
7653 sg->next = prev->next;
7654 cpus_or(*covered, *covered, *tmpmask);
7661 /* Calculate CPU power for physical packages and nodes */
7662 #ifdef CONFIG_SCHED_SMT
7663 for_each_cpu_mask_nr(i, *cpu_map) {
7664 struct sched_domain *sd = &per_cpu(cpu_domains, i);
7666 init_sched_groups_power(i, sd);
7669 #ifdef CONFIG_SCHED_MC
7670 for_each_cpu_mask_nr(i, *cpu_map) {
7671 struct sched_domain *sd = &per_cpu(core_domains, i);
7673 init_sched_groups_power(i, sd);
7677 for_each_cpu_mask_nr(i, *cpu_map) {
7678 struct sched_domain *sd = &per_cpu(phys_domains, i);
7680 init_sched_groups_power(i, sd);
7684 for (i = 0; i < nr_node_ids; i++)
7685 init_numa_sched_groups_power(sched_group_nodes[i]);
7688 struct sched_group *sg;
7690 cpu_to_allnodes_group(first_cpu(*cpu_map), cpu_map, &sg,
7692 init_numa_sched_groups_power(sg);
7696 /* Attach the domains */
7697 for_each_cpu_mask_nr(i, *cpu_map) {
7698 struct sched_domain *sd;
7699 #ifdef CONFIG_SCHED_SMT
7700 sd = &per_cpu(cpu_domains, i);
7701 #elif defined(CONFIG_SCHED_MC)
7702 sd = &per_cpu(core_domains, i);
7704 sd = &per_cpu(phys_domains, i);
7706 cpu_attach_domain(sd, rd, i);
7709 sched_cpumask_free(allmasks);
7714 free_sched_groups(cpu_map, tmpmask);
7715 sched_cpumask_free(allmasks);
7721 static int build_sched_domains(const cpumask_t *cpu_map)
7723 return __build_sched_domains(cpu_map, NULL);
7726 static cpumask_t *doms_cur; /* current sched domains */
7727 static int ndoms_cur; /* number of sched domains in 'doms_cur' */
7728 static struct sched_domain_attr *dattr_cur;
7729 /* attribues of custom domains in 'doms_cur' */
7732 * Special case: If a kmalloc of a doms_cur partition (array of
7733 * cpumask_t) fails, then fallback to a single sched domain,
7734 * as determined by the single cpumask_t fallback_doms.
7736 static cpumask_t fallback_doms;
7739 * arch_update_cpu_topology lets virtualized architectures update the
7740 * cpu core maps. It is supposed to return 1 if the topology changed
7741 * or 0 if it stayed the same.
7743 int __attribute__((weak)) arch_update_cpu_topology(void)
7749 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
7750 * For now this just excludes isolated cpus, but could be used to
7751 * exclude other special cases in the future.
7753 static int arch_init_sched_domains(const cpumask_t *cpu_map)
7757 arch_update_cpu_topology();
7759 doms_cur = kmalloc(sizeof(cpumask_t), GFP_KERNEL);
7761 doms_cur = &fallback_doms;
7762 cpus_andnot(*doms_cur, *cpu_map, cpu_isolated_map);
7764 err = build_sched_domains(doms_cur);
7765 register_sched_domain_sysctl();
7770 static void arch_destroy_sched_domains(const cpumask_t *cpu_map,
7773 free_sched_groups(cpu_map, tmpmask);
7777 * Detach sched domains from a group of cpus specified in cpu_map
7778 * These cpus will now be attached to the NULL domain
7780 static void detach_destroy_domains(const cpumask_t *cpu_map)
7785 for_each_cpu_mask_nr(i, *cpu_map)
7786 cpu_attach_domain(NULL, &def_root_domain, i);
7787 synchronize_sched();
7788 arch_destroy_sched_domains(cpu_map, &tmpmask);
7791 /* handle null as "default" */
7792 static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
7793 struct sched_domain_attr *new, int idx_new)
7795 struct sched_domain_attr tmp;
7802 return !memcmp(cur ? (cur + idx_cur) : &tmp,
7803 new ? (new + idx_new) : &tmp,
7804 sizeof(struct sched_domain_attr));
7808 * Partition sched domains as specified by the 'ndoms_new'
7809 * cpumasks in the array doms_new[] of cpumasks. This compares
7810 * doms_new[] to the current sched domain partitioning, doms_cur[].
7811 * It destroys each deleted domain and builds each new domain.
7813 * 'doms_new' is an array of cpumask_t's of length 'ndoms_new'.
7814 * The masks don't intersect (don't overlap.) We should setup one
7815 * sched domain for each mask. CPUs not in any of the cpumasks will
7816 * not be load balanced. If the same cpumask appears both in the
7817 * current 'doms_cur' domains and in the new 'doms_new', we can leave
7820 * The passed in 'doms_new' should be kmalloc'd. This routine takes
7821 * ownership of it and will kfree it when done with it. If the caller
7822 * failed the kmalloc call, then it can pass in doms_new == NULL &&
7823 * ndoms_new == 1, and partition_sched_domains() will fallback to
7824 * the single partition 'fallback_doms', it also forces the domains
7827 * If doms_new == NULL it will be replaced with cpu_online_map.
7828 * ndoms_new == 0 is a special case for destroying existing domains,
7829 * and it will not create the default domain.
7831 * Call with hotplug lock held
7833 void partition_sched_domains(int ndoms_new, cpumask_t *doms_new,
7834 struct sched_domain_attr *dattr_new)
7839 mutex_lock(&sched_domains_mutex);
7841 /* always unregister in case we don't destroy any domains */
7842 unregister_sched_domain_sysctl();
7844 /* Let architecture update cpu core mappings. */
7845 new_topology = arch_update_cpu_topology();
7847 n = doms_new ? ndoms_new : 0;
7849 /* Destroy deleted domains */
7850 for (i = 0; i < ndoms_cur; i++) {
7851 for (j = 0; j < n && !new_topology; j++) {
7852 if (cpus_equal(doms_cur[i], doms_new[j])
7853 && dattrs_equal(dattr_cur, i, dattr_new, j))
7856 /* no match - a current sched domain not in new doms_new[] */
7857 detach_destroy_domains(doms_cur + i);
7862 if (doms_new == NULL) {
7864 doms_new = &fallback_doms;
7865 cpus_andnot(doms_new[0], cpu_online_map, cpu_isolated_map);
7866 WARN_ON_ONCE(dattr_new);
7869 /* Build new domains */
7870 for (i = 0; i < ndoms_new; i++) {
7871 for (j = 0; j < ndoms_cur && !new_topology; j++) {
7872 if (cpus_equal(doms_new[i], doms_cur[j])
7873 && dattrs_equal(dattr_new, i, dattr_cur, j))
7876 /* no match - add a new doms_new */
7877 __build_sched_domains(doms_new + i,
7878 dattr_new ? dattr_new + i : NULL);
7883 /* Remember the new sched domains */
7884 if (doms_cur != &fallback_doms)
7886 kfree(dattr_cur); /* kfree(NULL) is safe */
7887 doms_cur = doms_new;
7888 dattr_cur = dattr_new;
7889 ndoms_cur = ndoms_new;
7891 register_sched_domain_sysctl();
7893 mutex_unlock(&sched_domains_mutex);
7896 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
7897 int arch_reinit_sched_domains(void)
7901 /* Destroy domains first to force the rebuild */
7902 partition_sched_domains(0, NULL, NULL);
7904 rebuild_sched_domains();
7910 static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt)
7914 if (buf[0] != '0' && buf[0] != '1')
7918 sched_smt_power_savings = (buf[0] == '1');
7920 sched_mc_power_savings = (buf[0] == '1');
7922 ret = arch_reinit_sched_domains();
7924 return ret ? ret : count;
7927 #ifdef CONFIG_SCHED_MC
7928 static ssize_t sched_mc_power_savings_show(struct sysdev_class *class,
7931 return sprintf(page, "%u\n", sched_mc_power_savings);
7933 static ssize_t sched_mc_power_savings_store(struct sysdev_class *class,
7934 const char *buf, size_t count)
7936 return sched_power_savings_store(buf, count, 0);
7938 static SYSDEV_CLASS_ATTR(sched_mc_power_savings, 0644,
7939 sched_mc_power_savings_show,
7940 sched_mc_power_savings_store);
7943 #ifdef CONFIG_SCHED_SMT
7944 static ssize_t sched_smt_power_savings_show(struct sysdev_class *dev,
7947 return sprintf(page, "%u\n", sched_smt_power_savings);
7949 static ssize_t sched_smt_power_savings_store(struct sysdev_class *dev,
7950 const char *buf, size_t count)
7952 return sched_power_savings_store(buf, count, 1);
7954 static SYSDEV_CLASS_ATTR(sched_smt_power_savings, 0644,
7955 sched_smt_power_savings_show,
7956 sched_smt_power_savings_store);
7959 int sched_create_sysfs_power_savings_entries(struct sysdev_class *cls)
7963 #ifdef CONFIG_SCHED_SMT
7965 err = sysfs_create_file(&cls->kset.kobj,
7966 &attr_sched_smt_power_savings.attr);
7968 #ifdef CONFIG_SCHED_MC
7969 if (!err && mc_capable())
7970 err = sysfs_create_file(&cls->kset.kobj,
7971 &attr_sched_mc_power_savings.attr);
7975 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
7977 #ifndef CONFIG_CPUSETS
7979 * Add online and remove offline CPUs from the scheduler domains.
7980 * When cpusets are enabled they take over this function.
7982 static int update_sched_domains(struct notifier_block *nfb,
7983 unsigned long action, void *hcpu)
7987 case CPU_ONLINE_FROZEN:
7989 case CPU_DEAD_FROZEN:
7990 partition_sched_domains(1, NULL, NULL);
7999 static int update_runtime(struct notifier_block *nfb,
8000 unsigned long action, void *hcpu)
8002 int cpu = (int)(long)hcpu;
8005 case CPU_DOWN_PREPARE:
8006 case CPU_DOWN_PREPARE_FROZEN:
8007 disable_runtime(cpu_rq(cpu));
8010 case CPU_DOWN_FAILED:
8011 case CPU_DOWN_FAILED_FROZEN:
8013 case CPU_ONLINE_FROZEN:
8014 enable_runtime(cpu_rq(cpu));
8022 void __init sched_init_smp(void)
8024 cpumask_t non_isolated_cpus;
8026 #if defined(CONFIG_NUMA)
8027 sched_group_nodes_bycpu = kzalloc(nr_cpu_ids * sizeof(void **),
8029 BUG_ON(sched_group_nodes_bycpu == NULL);
8032 mutex_lock(&sched_domains_mutex);
8033 arch_init_sched_domains(&cpu_online_map);
8034 cpus_andnot(non_isolated_cpus, cpu_possible_map, cpu_isolated_map);
8035 if (cpus_empty(non_isolated_cpus))
8036 cpu_set(smp_processor_id(), non_isolated_cpus);
8037 mutex_unlock(&sched_domains_mutex);
8040 #ifndef CONFIG_CPUSETS
8041 /* XXX: Theoretical race here - CPU may be hotplugged now */
8042 hotcpu_notifier(update_sched_domains, 0);
8045 /* RT runtime code needs to handle some hotplug events */
8046 hotcpu_notifier(update_runtime, 0);
8050 /* Move init over to a non-isolated CPU */
8051 if (set_cpus_allowed_ptr(current, &non_isolated_cpus) < 0)
8053 sched_init_granularity();
8056 void __init sched_init_smp(void)
8058 sched_init_granularity();
8060 #endif /* CONFIG_SMP */
8062 int in_sched_functions(unsigned long addr)
8064 return in_lock_functions(addr) ||
8065 (addr >= (unsigned long)__sched_text_start
8066 && addr < (unsigned long)__sched_text_end);
8069 static void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq)
8071 cfs_rq->tasks_timeline = RB_ROOT;
8072 INIT_LIST_HEAD(&cfs_rq->tasks);
8073 #ifdef CONFIG_FAIR_GROUP_SCHED
8076 cfs_rq->min_vruntime = (u64)(-(1LL << 20));
8079 static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
8081 struct rt_prio_array *array;
8084 array = &rt_rq->active;
8085 for (i = 0; i < MAX_RT_PRIO; i++) {
8086 INIT_LIST_HEAD(array->queue + i);
8087 __clear_bit(i, array->bitmap);
8089 /* delimiter for bitsearch: */
8090 __set_bit(MAX_RT_PRIO, array->bitmap);
8092 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
8093 rt_rq->highest_prio = MAX_RT_PRIO;
8096 rt_rq->rt_nr_migratory = 0;
8097 rt_rq->overloaded = 0;
8101 rt_rq->rt_throttled = 0;
8102 rt_rq->rt_runtime = 0;
8103 spin_lock_init(&rt_rq->rt_runtime_lock);
8105 #ifdef CONFIG_RT_GROUP_SCHED
8106 rt_rq->rt_nr_boosted = 0;
8111 #ifdef CONFIG_FAIR_GROUP_SCHED
8112 static void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
8113 struct sched_entity *se, int cpu, int add,
8114 struct sched_entity *parent)
8116 struct rq *rq = cpu_rq(cpu);
8117 tg->cfs_rq[cpu] = cfs_rq;
8118 init_cfs_rq(cfs_rq, rq);
8121 list_add(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list);
8124 /* se could be NULL for init_task_group */
8129 se->cfs_rq = &rq->cfs;
8131 se->cfs_rq = parent->my_q;
8134 se->load.weight = tg->shares;
8135 se->load.inv_weight = 0;
8136 se->parent = parent;
8140 #ifdef CONFIG_RT_GROUP_SCHED
8141 static void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
8142 struct sched_rt_entity *rt_se, int cpu, int add,
8143 struct sched_rt_entity *parent)
8145 struct rq *rq = cpu_rq(cpu);
8147 tg->rt_rq[cpu] = rt_rq;
8148 init_rt_rq(rt_rq, rq);
8150 rt_rq->rt_se = rt_se;
8151 rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime;
8153 list_add(&rt_rq->leaf_rt_rq_list, &rq->leaf_rt_rq_list);
8155 tg->rt_se[cpu] = rt_se;
8160 rt_se->rt_rq = &rq->rt;
8162 rt_se->rt_rq = parent->my_q;
8164 rt_se->my_q = rt_rq;
8165 rt_se->parent = parent;
8166 INIT_LIST_HEAD(&rt_se->run_list);
8170 void __init sched_init(void)
8173 unsigned long alloc_size = 0, ptr;
8175 #ifdef CONFIG_FAIR_GROUP_SCHED
8176 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
8178 #ifdef CONFIG_RT_GROUP_SCHED
8179 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
8181 #ifdef CONFIG_USER_SCHED
8185 * As sched_init() is called before page_alloc is setup,
8186 * we use alloc_bootmem().
8189 ptr = (unsigned long)alloc_bootmem(alloc_size);
8191 #ifdef CONFIG_FAIR_GROUP_SCHED
8192 init_task_group.se = (struct sched_entity **)ptr;
8193 ptr += nr_cpu_ids * sizeof(void **);
8195 init_task_group.cfs_rq = (struct cfs_rq **)ptr;
8196 ptr += nr_cpu_ids * sizeof(void **);
8198 #ifdef CONFIG_USER_SCHED
8199 root_task_group.se = (struct sched_entity **)ptr;
8200 ptr += nr_cpu_ids * sizeof(void **);
8202 root_task_group.cfs_rq = (struct cfs_rq **)ptr;
8203 ptr += nr_cpu_ids * sizeof(void **);
8204 #endif /* CONFIG_USER_SCHED */
8205 #endif /* CONFIG_FAIR_GROUP_SCHED */
8206 #ifdef CONFIG_RT_GROUP_SCHED
8207 init_task_group.rt_se = (struct sched_rt_entity **)ptr;
8208 ptr += nr_cpu_ids * sizeof(void **);
8210 init_task_group.rt_rq = (struct rt_rq **)ptr;
8211 ptr += nr_cpu_ids * sizeof(void **);
8213 #ifdef CONFIG_USER_SCHED
8214 root_task_group.rt_se = (struct sched_rt_entity **)ptr;
8215 ptr += nr_cpu_ids * sizeof(void **);
8217 root_task_group.rt_rq = (struct rt_rq **)ptr;
8218 ptr += nr_cpu_ids * sizeof(void **);
8219 #endif /* CONFIG_USER_SCHED */
8220 #endif /* CONFIG_RT_GROUP_SCHED */
8224 init_defrootdomain();
8227 init_rt_bandwidth(&def_rt_bandwidth,
8228 global_rt_period(), global_rt_runtime());
8230 #ifdef CONFIG_RT_GROUP_SCHED
8231 init_rt_bandwidth(&init_task_group.rt_bandwidth,
8232 global_rt_period(), global_rt_runtime());
8233 #ifdef CONFIG_USER_SCHED
8234 init_rt_bandwidth(&root_task_group.rt_bandwidth,
8235 global_rt_period(), RUNTIME_INF);
8236 #endif /* CONFIG_USER_SCHED */
8237 #endif /* CONFIG_RT_GROUP_SCHED */
8239 #ifdef CONFIG_GROUP_SCHED
8240 list_add(&init_task_group.list, &task_groups);
8241 INIT_LIST_HEAD(&init_task_group.children);
8243 #ifdef CONFIG_USER_SCHED
8244 INIT_LIST_HEAD(&root_task_group.children);
8245 init_task_group.parent = &root_task_group;
8246 list_add(&init_task_group.siblings, &root_task_group.children);
8247 #endif /* CONFIG_USER_SCHED */
8248 #endif /* CONFIG_GROUP_SCHED */
8250 for_each_possible_cpu(i) {
8254 spin_lock_init(&rq->lock);
8256 init_cfs_rq(&rq->cfs, rq);
8257 init_rt_rq(&rq->rt, rq);
8258 #ifdef CONFIG_FAIR_GROUP_SCHED
8259 init_task_group.shares = init_task_group_load;
8260 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
8261 #ifdef CONFIG_CGROUP_SCHED
8263 * How much cpu bandwidth does init_task_group get?
8265 * In case of task-groups formed thr' the cgroup filesystem, it
8266 * gets 100% of the cpu resources in the system. This overall
8267 * system cpu resource is divided among the tasks of
8268 * init_task_group and its child task-groups in a fair manner,
8269 * based on each entity's (task or task-group's) weight
8270 * (se->load.weight).
8272 * In other words, if init_task_group has 10 tasks of weight
8273 * 1024) and two child groups A0 and A1 (of weight 1024 each),
8274 * then A0's share of the cpu resource is:
8276 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
8278 * We achieve this by letting init_task_group's tasks sit
8279 * directly in rq->cfs (i.e init_task_group->se[] = NULL).
8281 init_tg_cfs_entry(&init_task_group, &rq->cfs, NULL, i, 1, NULL);
8282 #elif defined CONFIG_USER_SCHED
8283 root_task_group.shares = NICE_0_LOAD;
8284 init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, 0, NULL);
8286 * In case of task-groups formed thr' the user id of tasks,
8287 * init_task_group represents tasks belonging to root user.
8288 * Hence it forms a sibling of all subsequent groups formed.
8289 * In this case, init_task_group gets only a fraction of overall
8290 * system cpu resource, based on the weight assigned to root
8291 * user's cpu share (INIT_TASK_GROUP_LOAD). This is accomplished
8292 * by letting tasks of init_task_group sit in a separate cfs_rq
8293 * (init_cfs_rq) and having one entity represent this group of
8294 * tasks in rq->cfs (i.e init_task_group->se[] != NULL).
8296 init_tg_cfs_entry(&init_task_group,
8297 &per_cpu(init_cfs_rq, i),
8298 &per_cpu(init_sched_entity, i), i, 1,
8299 root_task_group.se[i]);
8302 #endif /* CONFIG_FAIR_GROUP_SCHED */
8304 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime;
8305 #ifdef CONFIG_RT_GROUP_SCHED
8306 INIT_LIST_HEAD(&rq->leaf_rt_rq_list);
8307 #ifdef CONFIG_CGROUP_SCHED
8308 init_tg_rt_entry(&init_task_group, &rq->rt, NULL, i, 1, NULL);
8309 #elif defined CONFIG_USER_SCHED
8310 init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, 0, NULL);
8311 init_tg_rt_entry(&init_task_group,
8312 &per_cpu(init_rt_rq, i),
8313 &per_cpu(init_sched_rt_entity, i), i, 1,
8314 root_task_group.rt_se[i]);
8318 for (j = 0; j < CPU_LOAD_IDX_MAX; j++)
8319 rq->cpu_load[j] = 0;
8323 rq->active_balance = 0;
8324 rq->next_balance = jiffies;
8328 rq->migration_thread = NULL;
8329 INIT_LIST_HEAD(&rq->migration_queue);
8330 rq_attach_root(rq, &def_root_domain);
8333 atomic_set(&rq->nr_iowait, 0);
8336 set_load_weight(&init_task);
8338 #ifdef CONFIG_PREEMPT_NOTIFIERS
8339 INIT_HLIST_HEAD(&init_task.preempt_notifiers);
8343 open_softirq(SCHED_SOFTIRQ, run_rebalance_domains);
8346 #ifdef CONFIG_RT_MUTEXES
8347 plist_head_init(&init_task.pi_waiters, &init_task.pi_lock);
8351 * The boot idle thread does lazy MMU switching as well:
8353 atomic_inc(&init_mm.mm_count);
8354 enter_lazy_tlb(&init_mm, current);
8357 * Make us the idle thread. Technically, schedule() should not be
8358 * called from this thread, however somewhere below it might be,
8359 * but because we are the idle thread, we just pick up running again
8360 * when this runqueue becomes "idle".
8362 init_idle(current, smp_processor_id());
8364 * During early bootup we pretend to be a normal task:
8366 current->sched_class = &fair_sched_class;
8368 scheduler_running = 1;
8371 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
8372 void __might_sleep(char *file, int line)
8375 static unsigned long prev_jiffy; /* ratelimiting */
8377 if ((!in_atomic() && !irqs_disabled()) ||
8378 system_state != SYSTEM_RUNNING || oops_in_progress)
8380 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
8382 prev_jiffy = jiffies;
8385 "BUG: sleeping function called from invalid context at %s:%d\n",
8388 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
8389 in_atomic(), irqs_disabled(),
8390 current->pid, current->comm);
8392 debug_show_held_locks(current);
8393 if (irqs_disabled())
8394 print_irqtrace_events(current);
8398 EXPORT_SYMBOL(__might_sleep);
8401 #ifdef CONFIG_MAGIC_SYSRQ
8402 static void normalize_task(struct rq *rq, struct task_struct *p)
8406 update_rq_clock(rq);
8407 on_rq = p->se.on_rq;
8409 deactivate_task(rq, p, 0);
8410 __setscheduler(rq, p, SCHED_NORMAL, 0);
8412 activate_task(rq, p, 0);
8413 resched_task(rq->curr);
8417 void normalize_rt_tasks(void)
8419 struct task_struct *g, *p;
8420 unsigned long flags;
8423 read_lock_irqsave(&tasklist_lock, flags);
8424 do_each_thread(g, p) {
8426 * Only normalize user tasks:
8431 p->se.exec_start = 0;
8432 #ifdef CONFIG_SCHEDSTATS
8433 p->se.wait_start = 0;
8434 p->se.sleep_start = 0;
8435 p->se.block_start = 0;
8440 * Renice negative nice level userspace
8443 if (TASK_NICE(p) < 0 && p->mm)
8444 set_user_nice(p, 0);
8448 spin_lock(&p->pi_lock);
8449 rq = __task_rq_lock(p);
8451 normalize_task(rq, p);
8453 __task_rq_unlock(rq);
8454 spin_unlock(&p->pi_lock);
8455 } while_each_thread(g, p);
8457 read_unlock_irqrestore(&tasklist_lock, flags);
8460 #endif /* CONFIG_MAGIC_SYSRQ */
8464 * These functions are only useful for the IA64 MCA handling.
8466 * They can only be called when the whole system has been
8467 * stopped - every CPU needs to be quiescent, and no scheduling
8468 * activity can take place. Using them for anything else would
8469 * be a serious bug, and as a result, they aren't even visible
8470 * under any other configuration.
8474 * curr_task - return the current task for a given cpu.
8475 * @cpu: the processor in question.
8477 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
8479 struct task_struct *curr_task(int cpu)
8481 return cpu_curr(cpu);
8485 * set_curr_task - set the current task for a given cpu.
8486 * @cpu: the processor in question.
8487 * @p: the task pointer to set.
8489 * Description: This function must only be used when non-maskable interrupts
8490 * are serviced on a separate stack. It allows the architecture to switch the
8491 * notion of the current task on a cpu in a non-blocking manner. This function
8492 * must be called with all CPU's synchronized, and interrupts disabled, the
8493 * and caller must save the original value of the current task (see
8494 * curr_task() above) and restore that value before reenabling interrupts and
8495 * re-starting the system.
8497 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
8499 void set_curr_task(int cpu, struct task_struct *p)
8506 #ifdef CONFIG_FAIR_GROUP_SCHED
8507 static void free_fair_sched_group(struct task_group *tg)
8511 for_each_possible_cpu(i) {
8513 kfree(tg->cfs_rq[i]);
8523 int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
8525 struct cfs_rq *cfs_rq;
8526 struct sched_entity *se;
8530 tg->cfs_rq = kzalloc(sizeof(cfs_rq) * nr_cpu_ids, GFP_KERNEL);
8533 tg->se = kzalloc(sizeof(se) * nr_cpu_ids, GFP_KERNEL);
8537 tg->shares = NICE_0_LOAD;
8539 for_each_possible_cpu(i) {
8542 cfs_rq = kzalloc_node(sizeof(struct cfs_rq),
8543 GFP_KERNEL, cpu_to_node(i));
8547 se = kzalloc_node(sizeof(struct sched_entity),
8548 GFP_KERNEL, cpu_to_node(i));
8552 init_tg_cfs_entry(tg, cfs_rq, se, i, 0, parent->se[i]);
8561 static inline void register_fair_sched_group(struct task_group *tg, int cpu)
8563 list_add_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list,
8564 &cpu_rq(cpu)->leaf_cfs_rq_list);
8567 static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
8569 list_del_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list);
8571 #else /* !CONFG_FAIR_GROUP_SCHED */
8572 static inline void free_fair_sched_group(struct task_group *tg)
8577 int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
8582 static inline void register_fair_sched_group(struct task_group *tg, int cpu)
8586 static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
8589 #endif /* CONFIG_FAIR_GROUP_SCHED */
8591 #ifdef CONFIG_RT_GROUP_SCHED
8592 static void free_rt_sched_group(struct task_group *tg)
8596 destroy_rt_bandwidth(&tg->rt_bandwidth);
8598 for_each_possible_cpu(i) {
8600 kfree(tg->rt_rq[i]);
8602 kfree(tg->rt_se[i]);
8610 int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
8612 struct rt_rq *rt_rq;
8613 struct sched_rt_entity *rt_se;
8617 tg->rt_rq = kzalloc(sizeof(rt_rq) * nr_cpu_ids, GFP_KERNEL);
8620 tg->rt_se = kzalloc(sizeof(rt_se) * nr_cpu_ids, GFP_KERNEL);
8624 init_rt_bandwidth(&tg->rt_bandwidth,
8625 ktime_to_ns(def_rt_bandwidth.rt_period), 0);
8627 for_each_possible_cpu(i) {
8630 rt_rq = kzalloc_node(sizeof(struct rt_rq),
8631 GFP_KERNEL, cpu_to_node(i));
8635 rt_se = kzalloc_node(sizeof(struct sched_rt_entity),
8636 GFP_KERNEL, cpu_to_node(i));
8640 init_tg_rt_entry(tg, rt_rq, rt_se, i, 0, parent->rt_se[i]);
8649 static inline void register_rt_sched_group(struct task_group *tg, int cpu)
8651 list_add_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list,
8652 &cpu_rq(cpu)->leaf_rt_rq_list);
8655 static inline void unregister_rt_sched_group(struct task_group *tg, int cpu)
8657 list_del_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list);
8659 #else /* !CONFIG_RT_GROUP_SCHED */
8660 static inline void free_rt_sched_group(struct task_group *tg)
8665 int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
8670 static inline void register_rt_sched_group(struct task_group *tg, int cpu)
8674 static inline void unregister_rt_sched_group(struct task_group *tg, int cpu)
8677 #endif /* CONFIG_RT_GROUP_SCHED */
8679 #ifdef CONFIG_GROUP_SCHED
8680 static void free_sched_group(struct task_group *tg)
8682 free_fair_sched_group(tg);
8683 free_rt_sched_group(tg);
8687 /* allocate runqueue etc for a new task group */
8688 struct task_group *sched_create_group(struct task_group *parent)
8690 struct task_group *tg;
8691 unsigned long flags;
8694 tg = kzalloc(sizeof(*tg), GFP_KERNEL);
8696 return ERR_PTR(-ENOMEM);
8698 if (!alloc_fair_sched_group(tg, parent))
8701 if (!alloc_rt_sched_group(tg, parent))
8704 spin_lock_irqsave(&task_group_lock, flags);
8705 for_each_possible_cpu(i) {
8706 register_fair_sched_group(tg, i);
8707 register_rt_sched_group(tg, i);
8709 list_add_rcu(&tg->list, &task_groups);
8711 WARN_ON(!parent); /* root should already exist */
8713 tg->parent = parent;
8714 INIT_LIST_HEAD(&tg->children);
8715 list_add_rcu(&tg->siblings, &parent->children);
8716 spin_unlock_irqrestore(&task_group_lock, flags);
8721 free_sched_group(tg);
8722 return ERR_PTR(-ENOMEM);
8725 /* rcu callback to free various structures associated with a task group */
8726 static void free_sched_group_rcu(struct rcu_head *rhp)
8728 /* now it should be safe to free those cfs_rqs */
8729 free_sched_group(container_of(rhp, struct task_group, rcu));
8732 /* Destroy runqueue etc associated with a task group */
8733 void sched_destroy_group(struct task_group *tg)
8735 unsigned long flags;
8738 spin_lock_irqsave(&task_group_lock, flags);
8739 for_each_possible_cpu(i) {
8740 unregister_fair_sched_group(tg, i);
8741 unregister_rt_sched_group(tg, i);
8743 list_del_rcu(&tg->list);
8744 list_del_rcu(&tg->siblings);
8745 spin_unlock_irqrestore(&task_group_lock, flags);
8747 /* wait for possible concurrent references to cfs_rqs complete */
8748 call_rcu(&tg->rcu, free_sched_group_rcu);
8751 /* change task's runqueue when it moves between groups.
8752 * The caller of this function should have put the task in its new group
8753 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
8754 * reflect its new group.
8756 void sched_move_task(struct task_struct *tsk)
8759 unsigned long flags;
8762 rq = task_rq_lock(tsk, &flags);
8764 update_rq_clock(rq);
8766 running = task_current(rq, tsk);
8767 on_rq = tsk->se.on_rq;
8770 dequeue_task(rq, tsk, 0);
8771 if (unlikely(running))
8772 tsk->sched_class->put_prev_task(rq, tsk);
8774 set_task_rq(tsk, task_cpu(tsk));
8776 #ifdef CONFIG_FAIR_GROUP_SCHED
8777 if (tsk->sched_class->moved_group)
8778 tsk->sched_class->moved_group(tsk);
8781 if (unlikely(running))
8782 tsk->sched_class->set_curr_task(rq);
8784 enqueue_task(rq, tsk, 0);
8786 task_rq_unlock(rq, &flags);
8788 #endif /* CONFIG_GROUP_SCHED */
8790 #ifdef CONFIG_FAIR_GROUP_SCHED
8791 static void __set_se_shares(struct sched_entity *se, unsigned long shares)
8793 struct cfs_rq *cfs_rq = se->cfs_rq;
8798 dequeue_entity(cfs_rq, se, 0);
8800 se->load.weight = shares;
8801 se->load.inv_weight = 0;
8804 enqueue_entity(cfs_rq, se, 0);
8807 static void set_se_shares(struct sched_entity *se, unsigned long shares)
8809 struct cfs_rq *cfs_rq = se->cfs_rq;
8810 struct rq *rq = cfs_rq->rq;
8811 unsigned long flags;
8813 spin_lock_irqsave(&rq->lock, flags);
8814 __set_se_shares(se, shares);
8815 spin_unlock_irqrestore(&rq->lock, flags);
8818 static DEFINE_MUTEX(shares_mutex);
8820 int sched_group_set_shares(struct task_group *tg, unsigned long shares)
8823 unsigned long flags;
8826 * We can't change the weight of the root cgroup.
8831 if (shares < MIN_SHARES)
8832 shares = MIN_SHARES;
8833 else if (shares > MAX_SHARES)
8834 shares = MAX_SHARES;
8836 mutex_lock(&shares_mutex);
8837 if (tg->shares == shares)
8840 spin_lock_irqsave(&task_group_lock, flags);
8841 for_each_possible_cpu(i)
8842 unregister_fair_sched_group(tg, i);
8843 list_del_rcu(&tg->siblings);
8844 spin_unlock_irqrestore(&task_group_lock, flags);
8846 /* wait for any ongoing reference to this group to finish */
8847 synchronize_sched();
8850 * Now we are free to modify the group's share on each cpu
8851 * w/o tripping rebalance_share or load_balance_fair.
8853 tg->shares = shares;
8854 for_each_possible_cpu(i) {
8858 cfs_rq_set_shares(tg->cfs_rq[i], 0);
8859 set_se_shares(tg->se[i], shares);
8863 * Enable load balance activity on this group, by inserting it back on
8864 * each cpu's rq->leaf_cfs_rq_list.
8866 spin_lock_irqsave(&task_group_lock, flags);
8867 for_each_possible_cpu(i)
8868 register_fair_sched_group(tg, i);
8869 list_add_rcu(&tg->siblings, &tg->parent->children);
8870 spin_unlock_irqrestore(&task_group_lock, flags);
8872 mutex_unlock(&shares_mutex);
8876 unsigned long sched_group_shares(struct task_group *tg)
8882 #ifdef CONFIG_RT_GROUP_SCHED
8884 * Ensure that the real time constraints are schedulable.
8886 static DEFINE_MUTEX(rt_constraints_mutex);
8888 static unsigned long to_ratio(u64 period, u64 runtime)
8890 if (runtime == RUNTIME_INF)
8893 return div64_u64(runtime << 20, period);
8896 /* Must be called with tasklist_lock held */
8897 static inline int tg_has_rt_tasks(struct task_group *tg)
8899 struct task_struct *g, *p;
8901 do_each_thread(g, p) {
8902 if (rt_task(p) && rt_rq_of_se(&p->rt)->tg == tg)
8904 } while_each_thread(g, p);
8909 struct rt_schedulable_data {
8910 struct task_group *tg;
8915 static int tg_schedulable(struct task_group *tg, void *data)
8917 struct rt_schedulable_data *d = data;
8918 struct task_group *child;
8919 unsigned long total, sum = 0;
8920 u64 period, runtime;
8922 period = ktime_to_ns(tg->rt_bandwidth.rt_period);
8923 runtime = tg->rt_bandwidth.rt_runtime;
8926 period = d->rt_period;
8927 runtime = d->rt_runtime;
8931 * Cannot have more runtime than the period.
8933 if (runtime > period && runtime != RUNTIME_INF)
8937 * Ensure we don't starve existing RT tasks.
8939 if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg))
8942 total = to_ratio(period, runtime);
8945 * Nobody can have more than the global setting allows.
8947 if (total > to_ratio(global_rt_period(), global_rt_runtime()))
8951 * The sum of our children's runtime should not exceed our own.
8953 list_for_each_entry_rcu(child, &tg->children, siblings) {
8954 period = ktime_to_ns(child->rt_bandwidth.rt_period);
8955 runtime = child->rt_bandwidth.rt_runtime;
8957 if (child == d->tg) {
8958 period = d->rt_period;
8959 runtime = d->rt_runtime;
8962 sum += to_ratio(period, runtime);
8971 static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
8973 struct rt_schedulable_data data = {
8975 .rt_period = period,
8976 .rt_runtime = runtime,
8979 return walk_tg_tree(tg_schedulable, tg_nop, &data);
8982 static int tg_set_bandwidth(struct task_group *tg,
8983 u64 rt_period, u64 rt_runtime)
8987 mutex_lock(&rt_constraints_mutex);
8988 read_lock(&tasklist_lock);
8989 err = __rt_schedulable(tg, rt_period, rt_runtime);
8993 spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock);
8994 tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period);
8995 tg->rt_bandwidth.rt_runtime = rt_runtime;
8997 for_each_possible_cpu(i) {
8998 struct rt_rq *rt_rq = tg->rt_rq[i];
9000 spin_lock(&rt_rq->rt_runtime_lock);
9001 rt_rq->rt_runtime = rt_runtime;
9002 spin_unlock(&rt_rq->rt_runtime_lock);
9004 spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock);
9006 read_unlock(&tasklist_lock);
9007 mutex_unlock(&rt_constraints_mutex);
9012 int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us)
9014 u64 rt_runtime, rt_period;
9016 rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period);
9017 rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC;
9018 if (rt_runtime_us < 0)
9019 rt_runtime = RUNTIME_INF;
9021 return tg_set_bandwidth(tg, rt_period, rt_runtime);
9024 long sched_group_rt_runtime(struct task_group *tg)
9028 if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF)
9031 rt_runtime_us = tg->rt_bandwidth.rt_runtime;
9032 do_div(rt_runtime_us, NSEC_PER_USEC);
9033 return rt_runtime_us;
9036 int sched_group_set_rt_period(struct task_group *tg, long rt_period_us)
9038 u64 rt_runtime, rt_period;
9040 rt_period = (u64)rt_period_us * NSEC_PER_USEC;
9041 rt_runtime = tg->rt_bandwidth.rt_runtime;
9046 return tg_set_bandwidth(tg, rt_period, rt_runtime);
9049 long sched_group_rt_period(struct task_group *tg)
9053 rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period);
9054 do_div(rt_period_us, NSEC_PER_USEC);
9055 return rt_period_us;
9058 static int sched_rt_global_constraints(void)
9060 u64 runtime, period;
9063 if (sysctl_sched_rt_period <= 0)
9066 runtime = global_rt_runtime();
9067 period = global_rt_period();
9070 * Sanity check on the sysctl variables.
9072 if (runtime > period && runtime != RUNTIME_INF)
9075 mutex_lock(&rt_constraints_mutex);
9076 read_lock(&tasklist_lock);
9077 ret = __rt_schedulable(NULL, 0, 0);
9078 read_unlock(&tasklist_lock);
9079 mutex_unlock(&rt_constraints_mutex);
9083 #else /* !CONFIG_RT_GROUP_SCHED */
9084 static int sched_rt_global_constraints(void)
9086 unsigned long flags;
9089 if (sysctl_sched_rt_period <= 0)
9092 spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
9093 for_each_possible_cpu(i) {
9094 struct rt_rq *rt_rq = &cpu_rq(i)->rt;
9096 spin_lock(&rt_rq->rt_runtime_lock);
9097 rt_rq->rt_runtime = global_rt_runtime();
9098 spin_unlock(&rt_rq->rt_runtime_lock);
9100 spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags);
9104 #endif /* CONFIG_RT_GROUP_SCHED */
9106 int sched_rt_handler(struct ctl_table *table, int write,
9107 struct file *filp, void __user *buffer, size_t *lenp,
9111 int old_period, old_runtime;
9112 static DEFINE_MUTEX(mutex);
9115 old_period = sysctl_sched_rt_period;
9116 old_runtime = sysctl_sched_rt_runtime;
9118 ret = proc_dointvec(table, write, filp, buffer, lenp, ppos);
9120 if (!ret && write) {
9121 ret = sched_rt_global_constraints();
9123 sysctl_sched_rt_period = old_period;
9124 sysctl_sched_rt_runtime = old_runtime;
9126 def_rt_bandwidth.rt_runtime = global_rt_runtime();
9127 def_rt_bandwidth.rt_period =
9128 ns_to_ktime(global_rt_period());
9131 mutex_unlock(&mutex);
9136 #ifdef CONFIG_CGROUP_SCHED
9138 /* return corresponding task_group object of a cgroup */
9139 static inline struct task_group *cgroup_tg(struct cgroup *cgrp)
9141 return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id),
9142 struct task_group, css);
9145 static struct cgroup_subsys_state *
9146 cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp)
9148 struct task_group *tg, *parent;
9150 if (!cgrp->parent) {
9151 /* This is early initialization for the top cgroup */
9152 return &init_task_group.css;
9155 parent = cgroup_tg(cgrp->parent);
9156 tg = sched_create_group(parent);
9158 return ERR_PTR(-ENOMEM);
9164 cpu_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
9166 struct task_group *tg = cgroup_tg(cgrp);
9168 sched_destroy_group(tg);
9172 cpu_cgroup_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
9173 struct task_struct *tsk)
9175 #ifdef CONFIG_RT_GROUP_SCHED
9176 /* Don't accept realtime tasks when there is no way for them to run */
9177 if (rt_task(tsk) && cgroup_tg(cgrp)->rt_bandwidth.rt_runtime == 0)
9180 /* We don't support RT-tasks being in separate groups */
9181 if (tsk->sched_class != &fair_sched_class)
9189 cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
9190 struct cgroup *old_cont, struct task_struct *tsk)
9192 sched_move_task(tsk);
9195 #ifdef CONFIG_FAIR_GROUP_SCHED
9196 static int cpu_shares_write_u64(struct cgroup *cgrp, struct cftype *cftype,
9199 return sched_group_set_shares(cgroup_tg(cgrp), shareval);
9202 static u64 cpu_shares_read_u64(struct cgroup *cgrp, struct cftype *cft)
9204 struct task_group *tg = cgroup_tg(cgrp);
9206 return (u64) tg->shares;
9208 #endif /* CONFIG_FAIR_GROUP_SCHED */
9210 #ifdef CONFIG_RT_GROUP_SCHED
9211 static int cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft,
9214 return sched_group_set_rt_runtime(cgroup_tg(cgrp), val);
9217 static s64 cpu_rt_runtime_read(struct cgroup *cgrp, struct cftype *cft)
9219 return sched_group_rt_runtime(cgroup_tg(cgrp));
9222 static int cpu_rt_period_write_uint(struct cgroup *cgrp, struct cftype *cftype,
9225 return sched_group_set_rt_period(cgroup_tg(cgrp), rt_period_us);
9228 static u64 cpu_rt_period_read_uint(struct cgroup *cgrp, struct cftype *cft)
9230 return sched_group_rt_period(cgroup_tg(cgrp));
9232 #endif /* CONFIG_RT_GROUP_SCHED */
9234 static struct cftype cpu_files[] = {
9235 #ifdef CONFIG_FAIR_GROUP_SCHED
9238 .read_u64 = cpu_shares_read_u64,
9239 .write_u64 = cpu_shares_write_u64,
9242 #ifdef CONFIG_RT_GROUP_SCHED
9244 .name = "rt_runtime_us",
9245 .read_s64 = cpu_rt_runtime_read,
9246 .write_s64 = cpu_rt_runtime_write,
9249 .name = "rt_period_us",
9250 .read_u64 = cpu_rt_period_read_uint,
9251 .write_u64 = cpu_rt_period_write_uint,
9256 static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont)
9258 return cgroup_add_files(cont, ss, cpu_files, ARRAY_SIZE(cpu_files));
9261 struct cgroup_subsys cpu_cgroup_subsys = {
9263 .create = cpu_cgroup_create,
9264 .destroy = cpu_cgroup_destroy,
9265 .can_attach = cpu_cgroup_can_attach,
9266 .attach = cpu_cgroup_attach,
9267 .populate = cpu_cgroup_populate,
9268 .subsys_id = cpu_cgroup_subsys_id,
9272 #endif /* CONFIG_CGROUP_SCHED */
9274 #ifdef CONFIG_CGROUP_CPUACCT
9277 * CPU accounting code for task groups.
9279 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
9280 * (balbir@in.ibm.com).
9283 /* track cpu usage of a group of tasks and its child groups */
9285 struct cgroup_subsys_state css;
9286 /* cpuusage holds pointer to a u64-type object on every cpu */
9288 struct cpuacct *parent;
9291 struct cgroup_subsys cpuacct_subsys;
9293 /* return cpu accounting group corresponding to this container */
9294 static inline struct cpuacct *cgroup_ca(struct cgroup *cgrp)
9296 return container_of(cgroup_subsys_state(cgrp, cpuacct_subsys_id),
9297 struct cpuacct, css);
9300 /* return cpu accounting group to which this task belongs */
9301 static inline struct cpuacct *task_ca(struct task_struct *tsk)
9303 return container_of(task_subsys_state(tsk, cpuacct_subsys_id),
9304 struct cpuacct, css);
9307 /* create a new cpu accounting group */
9308 static struct cgroup_subsys_state *cpuacct_create(
9309 struct cgroup_subsys *ss, struct cgroup *cgrp)
9311 struct cpuacct *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
9314 return ERR_PTR(-ENOMEM);
9316 ca->cpuusage = alloc_percpu(u64);
9317 if (!ca->cpuusage) {
9319 return ERR_PTR(-ENOMEM);
9323 ca->parent = cgroup_ca(cgrp->parent);
9328 /* destroy an existing cpu accounting group */
9330 cpuacct_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
9332 struct cpuacct *ca = cgroup_ca(cgrp);
9334 free_percpu(ca->cpuusage);
9338 static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu)
9340 u64 *cpuusage = percpu_ptr(ca->cpuusage, cpu);
9343 #ifndef CONFIG_64BIT
9345 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
9347 spin_lock_irq(&cpu_rq(cpu)->lock);
9349 spin_unlock_irq(&cpu_rq(cpu)->lock);
9357 static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val)
9359 u64 *cpuusage = percpu_ptr(ca->cpuusage, cpu);
9361 #ifndef CONFIG_64BIT
9363 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
9365 spin_lock_irq(&cpu_rq(cpu)->lock);
9367 spin_unlock_irq(&cpu_rq(cpu)->lock);
9373 /* return total cpu usage (in nanoseconds) of a group */
9374 static u64 cpuusage_read(struct cgroup *cgrp, struct cftype *cft)
9376 struct cpuacct *ca = cgroup_ca(cgrp);
9377 u64 totalcpuusage = 0;
9380 for_each_present_cpu(i)
9381 totalcpuusage += cpuacct_cpuusage_read(ca, i);
9383 return totalcpuusage;
9386 static int cpuusage_write(struct cgroup *cgrp, struct cftype *cftype,
9389 struct cpuacct *ca = cgroup_ca(cgrp);
9398 for_each_present_cpu(i)
9399 cpuacct_cpuusage_write(ca, i, 0);
9405 static int cpuacct_percpu_seq_read(struct cgroup *cgroup, struct cftype *cft,
9408 struct cpuacct *ca = cgroup_ca(cgroup);
9412 for_each_present_cpu(i) {
9413 percpu = cpuacct_cpuusage_read(ca, i);
9414 seq_printf(m, "%llu ", (unsigned long long) percpu);
9416 seq_printf(m, "\n");
9420 static struct cftype files[] = {
9423 .read_u64 = cpuusage_read,
9424 .write_u64 = cpuusage_write,
9427 .name = "usage_percpu",
9428 .read_seq_string = cpuacct_percpu_seq_read,
9433 static int cpuacct_populate(struct cgroup_subsys *ss, struct cgroup *cgrp)
9435 return cgroup_add_files(cgrp, ss, files, ARRAY_SIZE(files));
9439 * charge this task's execution time to its accounting group.
9441 * called with rq->lock held.
9443 static void cpuacct_charge(struct task_struct *tsk, u64 cputime)
9448 if (!cpuacct_subsys.active)
9451 cpu = task_cpu(tsk);
9454 for (; ca; ca = ca->parent) {
9455 u64 *cpuusage = percpu_ptr(ca->cpuusage, cpu);
9456 *cpuusage += cputime;
9460 struct cgroup_subsys cpuacct_subsys = {
9462 .create = cpuacct_create,
9463 .destroy = cpuacct_destroy,
9464 .populate = cpuacct_populate,
9465 .subsys_id = cpuacct_subsys_id,
9467 #endif /* CONFIG_CGROUP_CPUACCT */