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/seq_file.h>
59 #include <linux/sysctl.h>
60 #include <linux/syscalls.h>
61 #include <linux/times.h>
62 #include <linux/tsacct_kern.h>
63 #include <linux/kprobes.h>
64 #include <linux/delayacct.h>
65 #include <linux/reciprocal_div.h>
66 #include <linux/unistd.h>
67 #include <linux/pagemap.h>
68 #include <linux/hrtimer.h>
69 #include <linux/tick.h>
70 #include <linux/bootmem.h>
71 #include <linux/debugfs.h>
72 #include <linux/ctype.h>
73 #include <linux/ftrace.h>
76 #include <asm/irq_regs.h>
79 * Convert user-nice values [ -20 ... 0 ... 19 ]
80 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
83 #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
84 #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
85 #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
88 * 'User priority' is the nice value converted to something we
89 * can work with better when scaling various scheduler parameters,
90 * it's a [ 0 ... 39 ] range.
92 #define USER_PRIO(p) ((p)-MAX_RT_PRIO)
93 #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
94 #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
97 * Helpers for converting nanosecond timing to jiffy resolution
99 #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
101 #define NICE_0_LOAD SCHED_LOAD_SCALE
102 #define NICE_0_SHIFT SCHED_LOAD_SHIFT
105 * These are the 'tuning knobs' of the scheduler:
107 * default timeslice is 100 msecs (used only for SCHED_RR tasks).
108 * Timeslices get refilled after they expire.
110 #define DEF_TIMESLICE (100 * HZ / 1000)
113 * single value that denotes runtime == period, ie unlimited time.
115 #define RUNTIME_INF ((u64)~0ULL)
119 * Divide a load by a sched group cpu_power : (load / sg->__cpu_power)
120 * Since cpu_power is a 'constant', we can use a reciprocal divide.
122 static inline u32 sg_div_cpu_power(const struct sched_group *sg, u32 load)
124 return reciprocal_divide(load, sg->reciprocal_cpu_power);
128 * Each time a sched group cpu_power is changed,
129 * we must compute its reciprocal value
131 static inline void sg_inc_cpu_power(struct sched_group *sg, u32 val)
133 sg->__cpu_power += val;
134 sg->reciprocal_cpu_power = reciprocal_value(sg->__cpu_power);
138 static inline int rt_policy(int policy)
140 if (unlikely(policy == SCHED_FIFO || policy == SCHED_RR))
145 static inline int task_has_rt_policy(struct task_struct *p)
147 return rt_policy(p->policy);
151 * This is the priority-queue data structure of the RT scheduling class:
153 struct rt_prio_array {
154 DECLARE_BITMAP(bitmap, MAX_RT_PRIO+1); /* include 1 bit for delimiter */
155 struct list_head queue[MAX_RT_PRIO];
158 struct rt_bandwidth {
159 /* nests inside the rq lock: */
160 spinlock_t rt_runtime_lock;
163 struct hrtimer rt_period_timer;
166 static struct rt_bandwidth def_rt_bandwidth;
168 static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun);
170 static enum hrtimer_restart sched_rt_period_timer(struct hrtimer *timer)
172 struct rt_bandwidth *rt_b =
173 container_of(timer, struct rt_bandwidth, rt_period_timer);
179 now = hrtimer_cb_get_time(timer);
180 overrun = hrtimer_forward(timer, now, rt_b->rt_period);
185 idle = do_sched_rt_period_timer(rt_b, overrun);
188 return idle ? HRTIMER_NORESTART : HRTIMER_RESTART;
192 void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime)
194 rt_b->rt_period = ns_to_ktime(period);
195 rt_b->rt_runtime = runtime;
197 spin_lock_init(&rt_b->rt_runtime_lock);
199 hrtimer_init(&rt_b->rt_period_timer,
200 CLOCK_MONOTONIC, HRTIMER_MODE_REL);
201 rt_b->rt_period_timer.function = sched_rt_period_timer;
202 rt_b->rt_period_timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ;
205 static void start_rt_bandwidth(struct rt_bandwidth *rt_b)
209 if (rt_b->rt_runtime == RUNTIME_INF)
212 if (hrtimer_active(&rt_b->rt_period_timer))
215 spin_lock(&rt_b->rt_runtime_lock);
217 if (hrtimer_active(&rt_b->rt_period_timer))
220 now = hrtimer_cb_get_time(&rt_b->rt_period_timer);
221 hrtimer_forward(&rt_b->rt_period_timer, now, rt_b->rt_period);
222 hrtimer_start(&rt_b->rt_period_timer,
223 rt_b->rt_period_timer.expires,
226 spin_unlock(&rt_b->rt_runtime_lock);
229 #ifdef CONFIG_RT_GROUP_SCHED
230 static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b)
232 hrtimer_cancel(&rt_b->rt_period_timer);
237 * sched_domains_mutex serializes calls to arch_init_sched_domains,
238 * detach_destroy_domains and partition_sched_domains.
240 static DEFINE_MUTEX(sched_domains_mutex);
242 #ifdef CONFIG_GROUP_SCHED
244 #include <linux/cgroup.h>
248 static LIST_HEAD(task_groups);
250 /* task group related information */
252 #ifdef CONFIG_CGROUP_SCHED
253 struct cgroup_subsys_state css;
256 #ifdef CONFIG_FAIR_GROUP_SCHED
257 /* schedulable entities of this group on each cpu */
258 struct sched_entity **se;
259 /* runqueue "owned" by this group on each cpu */
260 struct cfs_rq **cfs_rq;
261 unsigned long shares;
264 #ifdef CONFIG_RT_GROUP_SCHED
265 struct sched_rt_entity **rt_se;
266 struct rt_rq **rt_rq;
268 struct rt_bandwidth rt_bandwidth;
272 struct list_head list;
274 struct task_group *parent;
275 struct list_head siblings;
276 struct list_head children;
279 #ifdef CONFIG_USER_SCHED
283 * Every UID task group (including init_task_group aka UID-0) will
284 * be a child to this group.
286 struct task_group root_task_group;
288 #ifdef CONFIG_FAIR_GROUP_SCHED
289 /* Default task group's sched entity on each cpu */
290 static DEFINE_PER_CPU(struct sched_entity, init_sched_entity);
291 /* Default task group's cfs_rq on each cpu */
292 static DEFINE_PER_CPU(struct cfs_rq, init_cfs_rq) ____cacheline_aligned_in_smp;
295 #ifdef CONFIG_RT_GROUP_SCHED
296 static DEFINE_PER_CPU(struct sched_rt_entity, init_sched_rt_entity);
297 static DEFINE_PER_CPU(struct rt_rq, init_rt_rq) ____cacheline_aligned_in_smp;
300 #define root_task_group init_task_group
303 /* task_group_lock serializes add/remove of task groups and also changes to
304 * a task group's cpu shares.
306 static DEFINE_SPINLOCK(task_group_lock);
308 #ifdef CONFIG_FAIR_GROUP_SCHED
309 #ifdef CONFIG_USER_SCHED
310 # define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD)
312 # define INIT_TASK_GROUP_LOAD NICE_0_LOAD
316 * A weight of 0 or 1 can cause arithmetics problems.
317 * A weight of a cfs_rq is the sum of weights of which entities
318 * are queued on this cfs_rq, so a weight of a entity should not be
319 * too large, so as the shares value of a task group.
320 * (The default weight is 1024 - so there's no practical
321 * limitation from this.)
324 #define MAX_SHARES (1UL << 18)
326 static int init_task_group_load = INIT_TASK_GROUP_LOAD;
329 /* Default task group.
330 * Every task in system belong to this group at bootup.
332 struct task_group init_task_group;
334 /* return group to which a task belongs */
335 static inline struct task_group *task_group(struct task_struct *p)
337 struct task_group *tg;
339 #ifdef CONFIG_USER_SCHED
341 #elif defined(CONFIG_CGROUP_SCHED)
342 tg = container_of(task_subsys_state(p, cpu_cgroup_subsys_id),
343 struct task_group, css);
345 tg = &init_task_group;
350 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
351 static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
353 #ifdef CONFIG_FAIR_GROUP_SCHED
354 p->se.cfs_rq = task_group(p)->cfs_rq[cpu];
355 p->se.parent = task_group(p)->se[cpu];
358 #ifdef CONFIG_RT_GROUP_SCHED
359 p->rt.rt_rq = task_group(p)->rt_rq[cpu];
360 p->rt.parent = task_group(p)->rt_se[cpu];
366 static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { }
368 #endif /* CONFIG_GROUP_SCHED */
370 /* CFS-related fields in a runqueue */
372 struct load_weight load;
373 unsigned long nr_running;
378 struct rb_root tasks_timeline;
379 struct rb_node *rb_leftmost;
381 struct list_head tasks;
382 struct list_head *balance_iterator;
385 * 'curr' points to currently running entity on this cfs_rq.
386 * It is set to NULL otherwise (i.e when none are currently running).
388 struct sched_entity *curr, *next;
390 unsigned long nr_spread_over;
392 #ifdef CONFIG_FAIR_GROUP_SCHED
393 struct rq *rq; /* cpu runqueue to which this cfs_rq is attached */
396 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
397 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
398 * (like users, containers etc.)
400 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
401 * list is used during load balance.
403 struct list_head leaf_cfs_rq_list;
404 struct task_group *tg; /* group that "owns" this runqueue */
408 /* Real-Time classes' related field in a runqueue: */
410 struct rt_prio_array active;
411 unsigned long rt_nr_running;
412 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
413 int highest_prio; /* highest queued rt task prio */
416 unsigned long rt_nr_migratory;
422 /* Nests inside the rq lock: */
423 spinlock_t rt_runtime_lock;
425 #ifdef CONFIG_RT_GROUP_SCHED
426 unsigned long rt_nr_boosted;
429 struct list_head leaf_rt_rq_list;
430 struct task_group *tg;
431 struct sched_rt_entity *rt_se;
438 * We add the notion of a root-domain which will be used to define per-domain
439 * variables. Each exclusive cpuset essentially defines an island domain by
440 * fully partitioning the member cpus from any other cpuset. Whenever a new
441 * exclusive cpuset is created, we also create and attach a new root-domain
451 * The "RT overload" flag: it gets set if a CPU has more than
452 * one runnable RT task.
459 * By default the system creates a single root-domain with all cpus as
460 * members (mimicking the global state we have today).
462 static struct root_domain def_root_domain;
467 * This is the main, per-CPU runqueue data structure.
469 * Locking rule: those places that want to lock multiple runqueues
470 * (such as the load balancing or the thread migration code), lock
471 * acquire operations must be ordered by ascending &runqueue.
478 * nr_running and cpu_load should be in the same cacheline because
479 * remote CPUs use both these fields when doing load calculation.
481 unsigned long nr_running;
482 #define CPU_LOAD_IDX_MAX 5
483 unsigned long cpu_load[CPU_LOAD_IDX_MAX];
484 unsigned char idle_at_tick;
486 unsigned long last_tick_seen;
487 unsigned char in_nohz_recently;
489 /* capture load from *all* tasks on this cpu: */
490 struct load_weight load;
491 unsigned long nr_load_updates;
497 #ifdef CONFIG_FAIR_GROUP_SCHED
498 /* list of leaf cfs_rq on this cpu: */
499 struct list_head leaf_cfs_rq_list;
501 #ifdef CONFIG_RT_GROUP_SCHED
502 struct list_head leaf_rt_rq_list;
506 * This is part of a global counter where only the total sum
507 * over all CPUs matters. A task can increase this counter on
508 * one CPU and if it got migrated afterwards it may decrease
509 * it on another CPU. Always updated under the runqueue lock:
511 unsigned long nr_uninterruptible;
513 struct task_struct *curr, *idle;
514 unsigned long next_balance;
515 struct mm_struct *prev_mm;
522 struct root_domain *rd;
523 struct sched_domain *sd;
525 /* For active balancing */
528 /* cpu of this runqueue: */
531 struct task_struct *migration_thread;
532 struct list_head migration_queue;
535 #ifdef CONFIG_SCHED_HRTICK
536 unsigned long hrtick_flags;
537 ktime_t hrtick_expire;
538 struct hrtimer hrtick_timer;
541 #ifdef CONFIG_SCHEDSTATS
543 struct sched_info rq_sched_info;
545 /* sys_sched_yield() stats */
546 unsigned int yld_exp_empty;
547 unsigned int yld_act_empty;
548 unsigned int yld_both_empty;
549 unsigned int yld_count;
551 /* schedule() stats */
552 unsigned int sched_switch;
553 unsigned int sched_count;
554 unsigned int sched_goidle;
556 /* try_to_wake_up() stats */
557 unsigned int ttwu_count;
558 unsigned int ttwu_local;
561 unsigned int bkl_count;
563 struct lock_class_key rq_lock_key;
566 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
568 static inline void check_preempt_curr(struct rq *rq, struct task_struct *p)
570 rq->curr->sched_class->check_preempt_curr(rq, p);
573 static inline int cpu_of(struct rq *rq)
583 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
584 * See detach_destroy_domains: synchronize_sched for details.
586 * The domain tree of any CPU may only be accessed from within
587 * preempt-disabled sections.
589 #define for_each_domain(cpu, __sd) \
590 for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
592 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
593 #define this_rq() (&__get_cpu_var(runqueues))
594 #define task_rq(p) cpu_rq(task_cpu(p))
595 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
597 static inline void update_rq_clock(struct rq *rq)
599 rq->clock = sched_clock_cpu(cpu_of(rq));
603 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
605 #ifdef CONFIG_SCHED_DEBUG
606 # define const_debug __read_mostly
608 # define const_debug static const
614 * Returns true if the current cpu runqueue is locked.
615 * This interface allows printk to be called with the runqueue lock
616 * held and know whether or not it is OK to wake up the klogd.
618 int runqueue_is_locked(void)
621 struct rq *rq = cpu_rq(cpu);
624 ret = spin_is_locked(&rq->lock);
630 * Debugging: various feature bits
633 #define SCHED_FEAT(name, enabled) \
634 __SCHED_FEAT_##name ,
637 #include "sched_features.h"
642 #define SCHED_FEAT(name, enabled) \
643 (1UL << __SCHED_FEAT_##name) * enabled |
645 const_debug unsigned int sysctl_sched_features =
646 #include "sched_features.h"
651 #ifdef CONFIG_SCHED_DEBUG
652 #define SCHED_FEAT(name, enabled) \
655 static __read_mostly char *sched_feat_names[] = {
656 #include "sched_features.h"
662 static int sched_feat_open(struct inode *inode, struct file *filp)
664 filp->private_data = inode->i_private;
669 sched_feat_read(struct file *filp, char __user *ubuf,
670 size_t cnt, loff_t *ppos)
677 for (i = 0; sched_feat_names[i]; i++) {
678 len += strlen(sched_feat_names[i]);
682 buf = kmalloc(len + 2, GFP_KERNEL);
686 for (i = 0; sched_feat_names[i]; i++) {
687 if (sysctl_sched_features & (1UL << i))
688 r += sprintf(buf + r, "%s ", sched_feat_names[i]);
690 r += sprintf(buf + r, "NO_%s ", sched_feat_names[i]);
693 r += sprintf(buf + r, "\n");
694 WARN_ON(r >= len + 2);
696 r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
704 sched_feat_write(struct file *filp, const char __user *ubuf,
705 size_t cnt, loff_t *ppos)
715 if (copy_from_user(&buf, ubuf, cnt))
720 if (strncmp(buf, "NO_", 3) == 0) {
725 for (i = 0; sched_feat_names[i]; i++) {
726 int len = strlen(sched_feat_names[i]);
728 if (strncmp(cmp, sched_feat_names[i], len) == 0) {
730 sysctl_sched_features &= ~(1UL << i);
732 sysctl_sched_features |= (1UL << i);
737 if (!sched_feat_names[i])
745 static struct file_operations sched_feat_fops = {
746 .open = sched_feat_open,
747 .read = sched_feat_read,
748 .write = sched_feat_write,
751 static __init int sched_init_debug(void)
753 debugfs_create_file("sched_features", 0644, NULL, NULL,
758 late_initcall(sched_init_debug);
762 #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
765 * Number of tasks to iterate in a single balance run.
766 * Limited because this is done with IRQs disabled.
768 const_debug unsigned int sysctl_sched_nr_migrate = 32;
771 * period over which we measure -rt task cpu usage in us.
774 unsigned int sysctl_sched_rt_period = 1000000;
776 static __read_mostly int scheduler_running;
779 * part of the period that we allow rt tasks to run in us.
782 int sysctl_sched_rt_runtime = 950000;
784 static inline u64 global_rt_period(void)
786 return (u64)sysctl_sched_rt_period * NSEC_PER_USEC;
789 static inline u64 global_rt_runtime(void)
791 if (sysctl_sched_rt_period < 0)
794 return (u64)sysctl_sched_rt_runtime * NSEC_PER_USEC;
797 unsigned long long time_sync_thresh = 100000;
799 static DEFINE_PER_CPU(unsigned long long, time_offset);
800 static DEFINE_PER_CPU(unsigned long long, prev_cpu_time);
803 * Global lock which we take every now and then to synchronize
804 * the CPUs time. This method is not warp-safe, but it's good
805 * enough to synchronize slowly diverging time sources and thus
806 * it's good enough for tracing:
808 static DEFINE_SPINLOCK(time_sync_lock);
809 static unsigned long long prev_global_time;
811 static unsigned long long __sync_cpu_clock(unsigned long long time, int cpu)
814 * We want this inlined, to not get tracer function calls
815 * in this critical section:
817 spin_acquire(&time_sync_lock.dep_map, 0, 0, _THIS_IP_);
818 __raw_spin_lock(&time_sync_lock.raw_lock);
820 if (time < prev_global_time) {
821 per_cpu(time_offset, cpu) += prev_global_time - time;
822 time = prev_global_time;
824 prev_global_time = time;
827 __raw_spin_unlock(&time_sync_lock.raw_lock);
828 spin_release(&time_sync_lock.dep_map, 1, _THIS_IP_);
833 static unsigned long long __cpu_clock(int cpu)
835 unsigned long long now;
838 * Only call sched_clock() if the scheduler has already been
839 * initialized (some code might call cpu_clock() very early):
841 if (unlikely(!scheduler_running))
844 now = sched_clock_cpu(cpu);
850 * For kernel-internal use: high-speed (but slightly incorrect) per-cpu
851 * clock constructed from sched_clock():
853 unsigned long long cpu_clock(int cpu)
855 unsigned long long prev_cpu_time, time, delta_time;
858 local_irq_save(flags);
859 prev_cpu_time = per_cpu(prev_cpu_time, cpu);
860 time = __cpu_clock(cpu) + per_cpu(time_offset, cpu);
861 delta_time = time-prev_cpu_time;
863 if (unlikely(delta_time > time_sync_thresh)) {
864 time = __sync_cpu_clock(time, cpu);
865 per_cpu(prev_cpu_time, cpu) = time;
867 local_irq_restore(flags);
871 EXPORT_SYMBOL_GPL(cpu_clock);
873 #ifndef prepare_arch_switch
874 # define prepare_arch_switch(next) do { } while (0)
876 #ifndef finish_arch_switch
877 # define finish_arch_switch(prev) do { } while (0)
880 static inline int task_current(struct rq *rq, struct task_struct *p)
882 return rq->curr == p;
885 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
886 static inline int task_running(struct rq *rq, struct task_struct *p)
888 return task_current(rq, p);
891 static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
895 static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
897 #ifdef CONFIG_DEBUG_SPINLOCK
898 /* this is a valid case when another task releases the spinlock */
899 rq->lock.owner = current;
902 * If we are tracking spinlock dependencies then we have to
903 * fix up the runqueue lock - which gets 'carried over' from
906 spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_);
908 spin_unlock_irq(&rq->lock);
911 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
912 static inline int task_running(struct rq *rq, struct task_struct *p)
917 return task_current(rq, p);
921 static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
925 * We can optimise this out completely for !SMP, because the
926 * SMP rebalancing from interrupt is the only thing that cares
931 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
932 spin_unlock_irq(&rq->lock);
934 spin_unlock(&rq->lock);
938 static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
942 * After ->oncpu is cleared, the task can be moved to a different CPU.
943 * We must ensure this doesn't happen until the switch is completely
949 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
953 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
956 * __task_rq_lock - lock the runqueue a given task resides on.
957 * Must be called interrupts disabled.
959 static inline struct rq *__task_rq_lock(struct task_struct *p)
963 struct rq *rq = task_rq(p);
964 spin_lock(&rq->lock);
965 if (likely(rq == task_rq(p)))
967 spin_unlock(&rq->lock);
972 * task_rq_lock - lock the runqueue a given task resides on and disable
973 * interrupts. Note the ordering: we can safely lookup the task_rq without
974 * explicitly disabling preemption.
976 static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags)
982 local_irq_save(*flags);
984 spin_lock(&rq->lock);
985 if (likely(rq == task_rq(p)))
987 spin_unlock_irqrestore(&rq->lock, *flags);
991 static void __task_rq_unlock(struct rq *rq)
994 spin_unlock(&rq->lock);
997 static inline void task_rq_unlock(struct rq *rq, unsigned long *flags)
1000 spin_unlock_irqrestore(&rq->lock, *flags);
1004 * this_rq_lock - lock this runqueue and disable interrupts.
1006 static struct rq *this_rq_lock(void)
1007 __acquires(rq->lock)
1011 local_irq_disable();
1013 spin_lock(&rq->lock);
1018 static void __resched_task(struct task_struct *p, int tif_bit);
1020 static inline void resched_task(struct task_struct *p)
1022 __resched_task(p, TIF_NEED_RESCHED);
1025 #ifdef CONFIG_SCHED_HRTICK
1027 * Use HR-timers to deliver accurate preemption points.
1029 * Its all a bit involved since we cannot program an hrt while holding the
1030 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
1033 * When we get rescheduled we reprogram the hrtick_timer outside of the
1036 static inline void resched_hrt(struct task_struct *p)
1038 __resched_task(p, TIF_HRTICK_RESCHED);
1041 static inline void resched_rq(struct rq *rq)
1043 unsigned long flags;
1045 spin_lock_irqsave(&rq->lock, flags);
1046 resched_task(rq->curr);
1047 spin_unlock_irqrestore(&rq->lock, flags);
1051 HRTICK_SET, /* re-programm hrtick_timer */
1052 HRTICK_RESET, /* not a new slice */
1053 HRTICK_BLOCK, /* stop hrtick operations */
1058 * - enabled by features
1059 * - hrtimer is actually high res
1061 static inline int hrtick_enabled(struct rq *rq)
1063 if (!sched_feat(HRTICK))
1065 if (unlikely(test_bit(HRTICK_BLOCK, &rq->hrtick_flags)))
1067 return hrtimer_is_hres_active(&rq->hrtick_timer);
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, int reset)
1077 assert_spin_locked(&rq->lock);
1080 * preempt at: now + delay
1083 ktime_add_ns(rq->hrtick_timer.base->get_time(), delay);
1085 * indicate we need to program the timer
1087 __set_bit(HRTICK_SET, &rq->hrtick_flags);
1089 __set_bit(HRTICK_RESET, &rq->hrtick_flags);
1092 * New slices are called from the schedule path and don't need a
1093 * forced reschedule.
1096 resched_hrt(rq->curr);
1099 static void hrtick_clear(struct rq *rq)
1101 if (hrtimer_active(&rq->hrtick_timer))
1102 hrtimer_cancel(&rq->hrtick_timer);
1106 * Update the timer from the possible pending state.
1108 static void hrtick_set(struct rq *rq)
1112 unsigned long flags;
1114 WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
1116 spin_lock_irqsave(&rq->lock, flags);
1117 set = __test_and_clear_bit(HRTICK_SET, &rq->hrtick_flags);
1118 reset = __test_and_clear_bit(HRTICK_RESET, &rq->hrtick_flags);
1119 time = rq->hrtick_expire;
1120 clear_thread_flag(TIF_HRTICK_RESCHED);
1121 spin_unlock_irqrestore(&rq->lock, flags);
1124 hrtimer_start(&rq->hrtick_timer, time, HRTIMER_MODE_ABS);
1125 if (reset && !hrtimer_active(&rq->hrtick_timer))
1132 * High-resolution timer tick.
1133 * Runs from hardirq context with interrupts disabled.
1135 static enum hrtimer_restart hrtick(struct hrtimer *timer)
1137 struct rq *rq = container_of(timer, struct rq, hrtick_timer);
1139 WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
1141 spin_lock(&rq->lock);
1142 update_rq_clock(rq);
1143 rq->curr->sched_class->task_tick(rq, rq->curr, 1);
1144 spin_unlock(&rq->lock);
1146 return HRTIMER_NORESTART;
1150 static void hotplug_hrtick_disable(int cpu)
1152 struct rq *rq = cpu_rq(cpu);
1153 unsigned long flags;
1155 spin_lock_irqsave(&rq->lock, flags);
1156 rq->hrtick_flags = 0;
1157 __set_bit(HRTICK_BLOCK, &rq->hrtick_flags);
1158 spin_unlock_irqrestore(&rq->lock, flags);
1163 static void hotplug_hrtick_enable(int cpu)
1165 struct rq *rq = cpu_rq(cpu);
1166 unsigned long flags;
1168 spin_lock_irqsave(&rq->lock, flags);
1169 __clear_bit(HRTICK_BLOCK, &rq->hrtick_flags);
1170 spin_unlock_irqrestore(&rq->lock, flags);
1174 hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu)
1176 int cpu = (int)(long)hcpu;
1179 case CPU_UP_CANCELED:
1180 case CPU_UP_CANCELED_FROZEN:
1181 case CPU_DOWN_PREPARE:
1182 case CPU_DOWN_PREPARE_FROZEN:
1184 case CPU_DEAD_FROZEN:
1185 hotplug_hrtick_disable(cpu);
1188 case CPU_UP_PREPARE:
1189 case CPU_UP_PREPARE_FROZEN:
1190 case CPU_DOWN_FAILED:
1191 case CPU_DOWN_FAILED_FROZEN:
1193 case CPU_ONLINE_FROZEN:
1194 hotplug_hrtick_enable(cpu);
1201 static void init_hrtick(void)
1203 hotcpu_notifier(hotplug_hrtick, 0);
1205 #endif /* CONFIG_SMP */
1207 static void init_rq_hrtick(struct rq *rq)
1209 rq->hrtick_flags = 0;
1210 hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1211 rq->hrtick_timer.function = hrtick;
1212 rq->hrtick_timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ;
1215 void hrtick_resched(void)
1218 unsigned long flags;
1220 if (!test_thread_flag(TIF_HRTICK_RESCHED))
1223 local_irq_save(flags);
1224 rq = cpu_rq(smp_processor_id());
1226 local_irq_restore(flags);
1229 static inline void hrtick_clear(struct rq *rq)
1233 static inline void hrtick_set(struct rq *rq)
1237 static inline void init_rq_hrtick(struct rq *rq)
1241 void hrtick_resched(void)
1245 static inline void init_hrtick(void)
1251 * resched_task - mark a task 'to be rescheduled now'.
1253 * On UP this means the setting of the need_resched flag, on SMP it
1254 * might also involve a cross-CPU call to trigger the scheduler on
1259 #ifndef tsk_is_polling
1260 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1263 static void __resched_task(struct task_struct *p, int tif_bit)
1267 assert_spin_locked(&task_rq(p)->lock);
1269 if (unlikely(test_tsk_thread_flag(p, tif_bit)))
1272 set_tsk_thread_flag(p, tif_bit);
1275 if (cpu == smp_processor_id())
1278 /* NEED_RESCHED must be visible before we test polling */
1280 if (!tsk_is_polling(p))
1281 smp_send_reschedule(cpu);
1284 static void resched_cpu(int cpu)
1286 struct rq *rq = cpu_rq(cpu);
1287 unsigned long flags;
1289 if (!spin_trylock_irqsave(&rq->lock, flags))
1291 resched_task(cpu_curr(cpu));
1292 spin_unlock_irqrestore(&rq->lock, flags);
1297 * When add_timer_on() enqueues a timer into the timer wheel of an
1298 * idle CPU then this timer might expire before the next timer event
1299 * which is scheduled to wake up that CPU. In case of a completely
1300 * idle system the next event might even be infinite time into the
1301 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1302 * leaves the inner idle loop so the newly added timer is taken into
1303 * account when the CPU goes back to idle and evaluates the timer
1304 * wheel for the next timer event.
1306 void wake_up_idle_cpu(int cpu)
1308 struct rq *rq = cpu_rq(cpu);
1310 if (cpu == smp_processor_id())
1314 * This is safe, as this function is called with the timer
1315 * wheel base lock of (cpu) held. When the CPU is on the way
1316 * to idle and has not yet set rq->curr to idle then it will
1317 * be serialized on the timer wheel base lock and take the new
1318 * timer into account automatically.
1320 if (rq->curr != rq->idle)
1324 * We can set TIF_RESCHED on the idle task of the other CPU
1325 * lockless. The worst case is that the other CPU runs the
1326 * idle task through an additional NOOP schedule()
1328 set_tsk_thread_flag(rq->idle, TIF_NEED_RESCHED);
1330 /* NEED_RESCHED must be visible before we test polling */
1332 if (!tsk_is_polling(rq->idle))
1333 smp_send_reschedule(cpu);
1338 static void __resched_task(struct task_struct *p, int tif_bit)
1340 assert_spin_locked(&task_rq(p)->lock);
1341 set_tsk_thread_flag(p, tif_bit);
1345 #if BITS_PER_LONG == 32
1346 # define WMULT_CONST (~0UL)
1348 # define WMULT_CONST (1UL << 32)
1351 #define WMULT_SHIFT 32
1354 * Shift right and round:
1356 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1358 static unsigned long
1359 calc_delta_mine(unsigned long delta_exec, unsigned long weight,
1360 struct load_weight *lw)
1364 if (!lw->inv_weight) {
1365 if (BITS_PER_LONG > 32 && unlikely(lw->weight >= WMULT_CONST))
1368 lw->inv_weight = 1 + (WMULT_CONST-lw->weight/2)
1372 tmp = (u64)delta_exec * weight;
1374 * Check whether we'd overflow the 64-bit multiplication:
1376 if (unlikely(tmp > WMULT_CONST))
1377 tmp = SRR(SRR(tmp, WMULT_SHIFT/2) * lw->inv_weight,
1380 tmp = SRR(tmp * lw->inv_weight, WMULT_SHIFT);
1382 return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX);
1385 static inline unsigned long
1386 calc_delta_fair(unsigned long delta_exec, struct load_weight *lw)
1388 return calc_delta_mine(delta_exec, NICE_0_LOAD, lw);
1391 static inline void update_load_add(struct load_weight *lw, unsigned long inc)
1397 static inline void update_load_sub(struct load_weight *lw, unsigned long dec)
1404 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1405 * of tasks with abnormal "nice" values across CPUs the contribution that
1406 * each task makes to its run queue's load is weighted according to its
1407 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1408 * scaled version of the new time slice allocation that they receive on time
1412 #define WEIGHT_IDLEPRIO 2
1413 #define WMULT_IDLEPRIO (1 << 31)
1416 * Nice levels are multiplicative, with a gentle 10% change for every
1417 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1418 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1419 * that remained on nice 0.
1421 * The "10% effect" is relative and cumulative: from _any_ nice level,
1422 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1423 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1424 * If a task goes up by ~10% and another task goes down by ~10% then
1425 * the relative distance between them is ~25%.)
1427 static const int prio_to_weight[40] = {
1428 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1429 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1430 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1431 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1432 /* 0 */ 1024, 820, 655, 526, 423,
1433 /* 5 */ 335, 272, 215, 172, 137,
1434 /* 10 */ 110, 87, 70, 56, 45,
1435 /* 15 */ 36, 29, 23, 18, 15,
1439 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1441 * In cases where the weight does not change often, we can use the
1442 * precalculated inverse to speed up arithmetics by turning divisions
1443 * into multiplications:
1445 static const u32 prio_to_wmult[40] = {
1446 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1447 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1448 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1449 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1450 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1451 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1452 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1453 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1456 static void activate_task(struct rq *rq, struct task_struct *p, int wakeup);
1459 * runqueue iterator, to support SMP load-balancing between different
1460 * scheduling classes, without having to expose their internal data
1461 * structures to the load-balancing proper:
1463 struct rq_iterator {
1465 struct task_struct *(*start)(void *);
1466 struct task_struct *(*next)(void *);
1470 static unsigned long
1471 balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
1472 unsigned long max_load_move, struct sched_domain *sd,
1473 enum cpu_idle_type idle, int *all_pinned,
1474 int *this_best_prio, struct rq_iterator *iterator);
1477 iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
1478 struct sched_domain *sd, enum cpu_idle_type idle,
1479 struct rq_iterator *iterator);
1482 #ifdef CONFIG_CGROUP_CPUACCT
1483 static void cpuacct_charge(struct task_struct *tsk, u64 cputime);
1485 static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}
1488 static inline void inc_cpu_load(struct rq *rq, unsigned long load)
1490 update_load_add(&rq->load, load);
1493 static inline void dec_cpu_load(struct rq *rq, unsigned long load)
1495 update_load_sub(&rq->load, load);
1499 static unsigned long source_load(int cpu, int type);
1500 static unsigned long target_load(int cpu, int type);
1501 static unsigned long cpu_avg_load_per_task(int cpu);
1502 static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd);
1503 #else /* CONFIG_SMP */
1505 #ifdef CONFIG_FAIR_GROUP_SCHED
1506 static void cfs_rq_set_shares(struct cfs_rq *cfs_rq, unsigned long shares)
1511 #endif /* CONFIG_SMP */
1513 #include "sched_stats.h"
1514 #include "sched_idletask.c"
1515 #include "sched_fair.c"
1516 #include "sched_rt.c"
1517 #ifdef CONFIG_SCHED_DEBUG
1518 # include "sched_debug.c"
1521 #define sched_class_highest (&rt_sched_class)
1523 static inline void inc_load(struct rq *rq, const struct task_struct *p)
1525 update_load_add(&rq->load, p->se.load.weight);
1528 static inline void dec_load(struct rq *rq, const struct task_struct *p)
1530 update_load_sub(&rq->load, p->se.load.weight);
1533 static void inc_nr_running(struct task_struct *p, struct rq *rq)
1539 static void dec_nr_running(struct task_struct *p, struct rq *rq)
1545 static void set_load_weight(struct task_struct *p)
1547 if (task_has_rt_policy(p)) {
1548 p->se.load.weight = prio_to_weight[0] * 2;
1549 p->se.load.inv_weight = prio_to_wmult[0] >> 1;
1554 * SCHED_IDLE tasks get minimal weight:
1556 if (p->policy == SCHED_IDLE) {
1557 p->se.load.weight = WEIGHT_IDLEPRIO;
1558 p->se.load.inv_weight = WMULT_IDLEPRIO;
1562 p->se.load.weight = prio_to_weight[p->static_prio - MAX_RT_PRIO];
1563 p->se.load.inv_weight = prio_to_wmult[p->static_prio - MAX_RT_PRIO];
1566 static void enqueue_task(struct rq *rq, struct task_struct *p, int wakeup)
1568 sched_info_queued(p);
1569 p->sched_class->enqueue_task(rq, p, wakeup);
1573 static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep)
1575 p->sched_class->dequeue_task(rq, p, sleep);
1580 * __normal_prio - return the priority that is based on the static prio
1582 static inline int __normal_prio(struct task_struct *p)
1584 return p->static_prio;
1588 * Calculate the expected normal priority: i.e. priority
1589 * without taking RT-inheritance into account. Might be
1590 * boosted by interactivity modifiers. Changes upon fork,
1591 * setprio syscalls, and whenever the interactivity
1592 * estimator recalculates.
1594 static inline int normal_prio(struct task_struct *p)
1598 if (task_has_rt_policy(p))
1599 prio = MAX_RT_PRIO-1 - p->rt_priority;
1601 prio = __normal_prio(p);
1606 * Calculate the current priority, i.e. the priority
1607 * taken into account by the scheduler. This value might
1608 * be boosted by RT tasks, or might be boosted by
1609 * interactivity modifiers. Will be RT if the task got
1610 * RT-boosted. If not then it returns p->normal_prio.
1612 static int effective_prio(struct task_struct *p)
1614 p->normal_prio = normal_prio(p);
1616 * If we are RT tasks or we were boosted to RT priority,
1617 * keep the priority unchanged. Otherwise, update priority
1618 * to the normal priority:
1620 if (!rt_prio(p->prio))
1621 return p->normal_prio;
1626 * activate_task - move a task to the runqueue.
1628 static void activate_task(struct rq *rq, struct task_struct *p, int wakeup)
1630 if (task_contributes_to_load(p))
1631 rq->nr_uninterruptible--;
1633 enqueue_task(rq, p, wakeup);
1634 inc_nr_running(p, rq);
1638 * deactivate_task - remove a task from the runqueue.
1640 static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep)
1642 if (task_contributes_to_load(p))
1643 rq->nr_uninterruptible++;
1645 dequeue_task(rq, p, sleep);
1646 dec_nr_running(p, rq);
1650 * task_curr - is this task currently executing on a CPU?
1651 * @p: the task in question.
1653 inline int task_curr(const struct task_struct *p)
1655 return cpu_curr(task_cpu(p)) == p;
1658 /* Used instead of source_load when we know the type == 0 */
1659 unsigned long weighted_cpuload(const int cpu)
1661 return cpu_rq(cpu)->load.weight;
1664 static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
1666 set_task_rq(p, cpu);
1669 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1670 * successfuly executed on another CPU. We must ensure that updates of
1671 * per-task data have been completed by this moment.
1674 task_thread_info(p)->cpu = cpu;
1678 static inline void check_class_changed(struct rq *rq, struct task_struct *p,
1679 const struct sched_class *prev_class,
1680 int oldprio, int running)
1682 if (prev_class != p->sched_class) {
1683 if (prev_class->switched_from)
1684 prev_class->switched_from(rq, p, running);
1685 p->sched_class->switched_to(rq, p, running);
1687 p->sched_class->prio_changed(rq, p, oldprio, running);
1693 * Is this task likely cache-hot:
1696 task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
1701 * Buddy candidates are cache hot:
1703 if (sched_feat(CACHE_HOT_BUDDY) && (&p->se == cfs_rq_of(&p->se)->next))
1706 if (p->sched_class != &fair_sched_class)
1709 if (sysctl_sched_migration_cost == -1)
1711 if (sysctl_sched_migration_cost == 0)
1714 delta = now - p->se.exec_start;
1716 return delta < (s64)sysctl_sched_migration_cost;
1720 void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
1722 int old_cpu = task_cpu(p);
1723 struct rq *old_rq = cpu_rq(old_cpu), *new_rq = cpu_rq(new_cpu);
1724 struct cfs_rq *old_cfsrq = task_cfs_rq(p),
1725 *new_cfsrq = cpu_cfs_rq(old_cfsrq, new_cpu);
1728 clock_offset = old_rq->clock - new_rq->clock;
1730 #ifdef CONFIG_SCHEDSTATS
1731 if (p->se.wait_start)
1732 p->se.wait_start -= clock_offset;
1733 if (p->se.sleep_start)
1734 p->se.sleep_start -= clock_offset;
1735 if (p->se.block_start)
1736 p->se.block_start -= clock_offset;
1737 if (old_cpu != new_cpu) {
1738 schedstat_inc(p, se.nr_migrations);
1739 if (task_hot(p, old_rq->clock, NULL))
1740 schedstat_inc(p, se.nr_forced2_migrations);
1743 p->se.vruntime -= old_cfsrq->min_vruntime -
1744 new_cfsrq->min_vruntime;
1746 __set_task_cpu(p, new_cpu);
1749 struct migration_req {
1750 struct list_head list;
1752 struct task_struct *task;
1755 struct completion done;
1759 * The task's runqueue lock must be held.
1760 * Returns true if you have to wait for migration thread.
1763 migrate_task(struct task_struct *p, int dest_cpu, struct migration_req *req)
1765 struct rq *rq = task_rq(p);
1768 * If the task is not on a runqueue (and not running), then
1769 * it is sufficient to simply update the task's cpu field.
1771 if (!p->se.on_rq && !task_running(rq, p)) {
1772 set_task_cpu(p, dest_cpu);
1776 init_completion(&req->done);
1778 req->dest_cpu = dest_cpu;
1779 list_add(&req->list, &rq->migration_queue);
1785 * wait_task_inactive - wait for a thread to unschedule.
1787 * The caller must ensure that the task *will* unschedule sometime soon,
1788 * else this function might spin for a *long* time. This function can't
1789 * be called with interrupts off, or it may introduce deadlock with
1790 * smp_call_function() if an IPI is sent by the same process we are
1791 * waiting to become inactive.
1793 void wait_task_inactive(struct task_struct *p)
1795 unsigned long flags;
1801 * We do the initial early heuristics without holding
1802 * any task-queue locks at all. We'll only try to get
1803 * the runqueue lock when things look like they will
1809 * If the task is actively running on another CPU
1810 * still, just relax and busy-wait without holding
1813 * NOTE! Since we don't hold any locks, it's not
1814 * even sure that "rq" stays as the right runqueue!
1815 * But we don't care, since "task_running()" will
1816 * return false if the runqueue has changed and p
1817 * is actually now running somewhere else!
1819 while (task_running(rq, p))
1823 * Ok, time to look more closely! We need the rq
1824 * lock now, to be *sure*. If we're wrong, we'll
1825 * just go back and repeat.
1827 rq = task_rq_lock(p, &flags);
1828 running = task_running(rq, p);
1829 on_rq = p->se.on_rq;
1830 task_rq_unlock(rq, &flags);
1833 * Was it really running after all now that we
1834 * checked with the proper locks actually held?
1836 * Oops. Go back and try again..
1838 if (unlikely(running)) {
1844 * It's not enough that it's not actively running,
1845 * it must be off the runqueue _entirely_, and not
1848 * So if it wa still runnable (but just not actively
1849 * running right now), it's preempted, and we should
1850 * yield - it could be a while.
1852 if (unlikely(on_rq)) {
1853 schedule_timeout_uninterruptible(1);
1858 * Ahh, all good. It wasn't running, and it wasn't
1859 * runnable, which means that it will never become
1860 * running in the future either. We're all done!
1867 * kick_process - kick a running thread to enter/exit the kernel
1868 * @p: the to-be-kicked thread
1870 * Cause a process which is running on another CPU to enter
1871 * kernel-mode, without any delay. (to get signals handled.)
1873 * NOTE: this function doesnt have to take the runqueue lock,
1874 * because all it wants to ensure is that the remote task enters
1875 * the kernel. If the IPI races and the task has been migrated
1876 * to another CPU then no harm is done and the purpose has been
1879 void kick_process(struct task_struct *p)
1885 if ((cpu != smp_processor_id()) && task_curr(p))
1886 smp_send_reschedule(cpu);
1891 * Return a low guess at the load of a migration-source cpu weighted
1892 * according to the scheduling class and "nice" value.
1894 * We want to under-estimate the load of migration sources, to
1895 * balance conservatively.
1897 static unsigned long source_load(int cpu, int type)
1899 struct rq *rq = cpu_rq(cpu);
1900 unsigned long total = weighted_cpuload(cpu);
1905 return min(rq->cpu_load[type-1], total);
1909 * Return a high guess at the load of a migration-target cpu weighted
1910 * according to the scheduling class and "nice" value.
1912 static unsigned long target_load(int cpu, int type)
1914 struct rq *rq = cpu_rq(cpu);
1915 unsigned long total = weighted_cpuload(cpu);
1920 return max(rq->cpu_load[type-1], total);
1924 * Return the average load per task on the cpu's run queue
1926 static unsigned long cpu_avg_load_per_task(int cpu)
1928 struct rq *rq = cpu_rq(cpu);
1929 unsigned long total = weighted_cpuload(cpu);
1930 unsigned long n = rq->nr_running;
1932 return n ? total / n : SCHED_LOAD_SCALE;
1936 * find_idlest_group finds and returns the least busy CPU group within the
1939 static struct sched_group *
1940 find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu)
1942 struct sched_group *idlest = NULL, *this = NULL, *group = sd->groups;
1943 unsigned long min_load = ULONG_MAX, this_load = 0;
1944 int load_idx = sd->forkexec_idx;
1945 int imbalance = 100 + (sd->imbalance_pct-100)/2;
1948 unsigned long load, avg_load;
1952 /* Skip over this group if it has no CPUs allowed */
1953 if (!cpus_intersects(group->cpumask, p->cpus_allowed))
1956 local_group = cpu_isset(this_cpu, group->cpumask);
1958 /* Tally up the load of all CPUs in the group */
1961 for_each_cpu_mask(i, group->cpumask) {
1962 /* Bias balancing toward cpus of our domain */
1964 load = source_load(i, load_idx);
1966 load = target_load(i, load_idx);
1971 /* Adjust by relative CPU power of the group */
1972 avg_load = sg_div_cpu_power(group,
1973 avg_load * SCHED_LOAD_SCALE);
1976 this_load = avg_load;
1978 } else if (avg_load < min_load) {
1979 min_load = avg_load;
1982 } while (group = group->next, group != sd->groups);
1984 if (!idlest || 100*this_load < imbalance*min_load)
1990 * find_idlest_cpu - find the idlest cpu among the cpus in group.
1993 find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu,
1996 unsigned long load, min_load = ULONG_MAX;
2000 /* Traverse only the allowed CPUs */
2001 cpus_and(*tmp, group->cpumask, p->cpus_allowed);
2003 for_each_cpu_mask(i, *tmp) {
2004 load = weighted_cpuload(i);
2006 if (load < min_load || (load == min_load && i == this_cpu)) {
2016 * sched_balance_self: balance the current task (running on cpu) in domains
2017 * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
2020 * Balance, ie. select the least loaded group.
2022 * Returns the target CPU number, or the same CPU if no balancing is needed.
2024 * preempt must be disabled.
2026 static int sched_balance_self(int cpu, int flag)
2028 struct task_struct *t = current;
2029 struct sched_domain *tmp, *sd = NULL;
2031 for_each_domain(cpu, tmp) {
2033 * If power savings logic is enabled for a domain, stop there.
2035 if (tmp->flags & SD_POWERSAVINGS_BALANCE)
2037 if (tmp->flags & flag)
2042 cpumask_t span, tmpmask;
2043 struct sched_group *group;
2044 int new_cpu, weight;
2046 if (!(sd->flags & flag)) {
2052 group = find_idlest_group(sd, t, cpu);
2058 new_cpu = find_idlest_cpu(group, t, cpu, &tmpmask);
2059 if (new_cpu == -1 || new_cpu == cpu) {
2060 /* Now try balancing at a lower domain level of cpu */
2065 /* Now try balancing at a lower domain level of new_cpu */
2068 weight = cpus_weight(span);
2069 for_each_domain(cpu, tmp) {
2070 if (weight <= cpus_weight(tmp->span))
2072 if (tmp->flags & flag)
2075 /* while loop will break here if sd == NULL */
2081 #endif /* CONFIG_SMP */
2084 * try_to_wake_up - wake up a thread
2085 * @p: the to-be-woken-up thread
2086 * @state: the mask of task states that can be woken
2087 * @sync: do a synchronous wakeup?
2089 * Put it on the run-queue if it's not already there. The "current"
2090 * thread is always on the run-queue (except when the actual
2091 * re-schedule is in progress), and as such you're allowed to do
2092 * the simpler "current->state = TASK_RUNNING" to mark yourself
2093 * runnable without the overhead of this.
2095 * returns failure only if the task is already active.
2097 static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync)
2099 int cpu, orig_cpu, this_cpu, success = 0;
2100 unsigned long flags;
2104 if (!sched_feat(SYNC_WAKEUPS))
2108 rq = task_rq_lock(p, &flags);
2109 old_state = p->state;
2110 if (!(old_state & state))
2118 this_cpu = smp_processor_id();
2121 if (unlikely(task_running(rq, p)))
2124 cpu = p->sched_class->select_task_rq(p, sync);
2125 if (cpu != orig_cpu) {
2126 set_task_cpu(p, cpu);
2127 task_rq_unlock(rq, &flags);
2128 /* might preempt at this point */
2129 rq = task_rq_lock(p, &flags);
2130 old_state = p->state;
2131 if (!(old_state & state))
2136 this_cpu = smp_processor_id();
2140 #ifdef CONFIG_SCHEDSTATS
2141 schedstat_inc(rq, ttwu_count);
2142 if (cpu == this_cpu)
2143 schedstat_inc(rq, ttwu_local);
2145 struct sched_domain *sd;
2146 for_each_domain(this_cpu, sd) {
2147 if (cpu_isset(cpu, sd->span)) {
2148 schedstat_inc(sd, ttwu_wake_remote);
2156 #endif /* CONFIG_SMP */
2157 schedstat_inc(p, se.nr_wakeups);
2159 schedstat_inc(p, se.nr_wakeups_sync);
2160 if (orig_cpu != cpu)
2161 schedstat_inc(p, se.nr_wakeups_migrate);
2162 if (cpu == this_cpu)
2163 schedstat_inc(p, se.nr_wakeups_local);
2165 schedstat_inc(p, se.nr_wakeups_remote);
2166 update_rq_clock(rq);
2167 activate_task(rq, p, 1);
2171 trace_mark(kernel_sched_wakeup,
2172 "pid %d state %ld ## rq %p task %p rq->curr %p",
2173 p->pid, p->state, rq, p, rq->curr);
2174 check_preempt_curr(rq, p);
2176 p->state = TASK_RUNNING;
2178 if (p->sched_class->task_wake_up)
2179 p->sched_class->task_wake_up(rq, p);
2182 task_rq_unlock(rq, &flags);
2187 int wake_up_process(struct task_struct *p)
2189 return try_to_wake_up(p, TASK_ALL, 0);
2191 EXPORT_SYMBOL(wake_up_process);
2193 int wake_up_state(struct task_struct *p, unsigned int state)
2195 return try_to_wake_up(p, state, 0);
2199 * Perform scheduler related setup for a newly forked process p.
2200 * p is forked by current.
2202 * __sched_fork() is basic setup used by init_idle() too:
2204 static void __sched_fork(struct task_struct *p)
2206 p->se.exec_start = 0;
2207 p->se.sum_exec_runtime = 0;
2208 p->se.prev_sum_exec_runtime = 0;
2209 p->se.last_wakeup = 0;
2210 p->se.avg_overlap = 0;
2212 #ifdef CONFIG_SCHEDSTATS
2213 p->se.wait_start = 0;
2214 p->se.sum_sleep_runtime = 0;
2215 p->se.sleep_start = 0;
2216 p->se.block_start = 0;
2217 p->se.sleep_max = 0;
2218 p->se.block_max = 0;
2220 p->se.slice_max = 0;
2224 INIT_LIST_HEAD(&p->rt.run_list);
2226 INIT_LIST_HEAD(&p->se.group_node);
2228 #ifdef CONFIG_PREEMPT_NOTIFIERS
2229 INIT_HLIST_HEAD(&p->preempt_notifiers);
2233 * We mark the process as running here, but have not actually
2234 * inserted it onto the runqueue yet. This guarantees that
2235 * nobody will actually run it, and a signal or other external
2236 * event cannot wake it up and insert it on the runqueue either.
2238 p->state = TASK_RUNNING;
2242 * fork()/clone()-time setup:
2244 void sched_fork(struct task_struct *p, int clone_flags)
2246 int cpu = get_cpu();
2251 cpu = sched_balance_self(cpu, SD_BALANCE_FORK);
2253 set_task_cpu(p, cpu);
2256 * Make sure we do not leak PI boosting priority to the child:
2258 p->prio = current->normal_prio;
2259 if (!rt_prio(p->prio))
2260 p->sched_class = &fair_sched_class;
2262 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2263 if (likely(sched_info_on()))
2264 memset(&p->sched_info, 0, sizeof(p->sched_info));
2266 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
2269 #ifdef CONFIG_PREEMPT
2270 /* Want to start with kernel preemption disabled. */
2271 task_thread_info(p)->preempt_count = 1;
2277 * wake_up_new_task - wake up a newly created task for the first time.
2279 * This function will do some initial scheduler statistics housekeeping
2280 * that must be done for every newly created context, then puts the task
2281 * on the runqueue and wakes it.
2283 void wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
2285 unsigned long flags;
2288 rq = task_rq_lock(p, &flags);
2289 BUG_ON(p->state != TASK_RUNNING);
2290 update_rq_clock(rq);
2292 p->prio = effective_prio(p);
2294 if (!p->sched_class->task_new || !current->se.on_rq) {
2295 activate_task(rq, p, 0);
2298 * Let the scheduling class do new task startup
2299 * management (if any):
2301 p->sched_class->task_new(rq, p);
2302 inc_nr_running(p, rq);
2304 trace_mark(kernel_sched_wakeup_new,
2305 "pid %d state %ld ## rq %p task %p rq->curr %p",
2306 p->pid, p->state, rq, p, rq->curr);
2307 check_preempt_curr(rq, p);
2309 if (p->sched_class->task_wake_up)
2310 p->sched_class->task_wake_up(rq, p);
2312 task_rq_unlock(rq, &flags);
2315 #ifdef CONFIG_PREEMPT_NOTIFIERS
2318 * preempt_notifier_register - tell me when current is being being preempted & rescheduled
2319 * @notifier: notifier struct to register
2321 void preempt_notifier_register(struct preempt_notifier *notifier)
2323 hlist_add_head(¬ifier->link, ¤t->preempt_notifiers);
2325 EXPORT_SYMBOL_GPL(preempt_notifier_register);
2328 * preempt_notifier_unregister - no longer interested in preemption notifications
2329 * @notifier: notifier struct to unregister
2331 * This is safe to call from within a preemption notifier.
2333 void preempt_notifier_unregister(struct preempt_notifier *notifier)
2335 hlist_del(¬ifier->link);
2337 EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
2339 static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
2341 struct preempt_notifier *notifier;
2342 struct hlist_node *node;
2344 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
2345 notifier->ops->sched_in(notifier, raw_smp_processor_id());
2349 fire_sched_out_preempt_notifiers(struct task_struct *curr,
2350 struct task_struct *next)
2352 struct preempt_notifier *notifier;
2353 struct hlist_node *node;
2355 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
2356 notifier->ops->sched_out(notifier, next);
2361 static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
2366 fire_sched_out_preempt_notifiers(struct task_struct *curr,
2367 struct task_struct *next)
2374 * prepare_task_switch - prepare to switch tasks
2375 * @rq: the runqueue preparing to switch
2376 * @prev: the current task that is being switched out
2377 * @next: the task we are going to switch to.
2379 * This is called with the rq lock held and interrupts off. It must
2380 * be paired with a subsequent finish_task_switch after the context
2383 * prepare_task_switch sets up locking and calls architecture specific
2387 prepare_task_switch(struct rq *rq, struct task_struct *prev,
2388 struct task_struct *next)
2390 fire_sched_out_preempt_notifiers(prev, next);
2391 prepare_lock_switch(rq, next);
2392 prepare_arch_switch(next);
2396 * finish_task_switch - clean up after a task-switch
2397 * @rq: runqueue associated with task-switch
2398 * @prev: the thread we just switched away from.
2400 * finish_task_switch must be called after the context switch, paired
2401 * with a prepare_task_switch call before the context switch.
2402 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2403 * and do any other architecture-specific cleanup actions.
2405 * Note that we may have delayed dropping an mm in context_switch(). If
2406 * so, we finish that here outside of the runqueue lock. (Doing it
2407 * with the lock held can cause deadlocks; see schedule() for
2410 static void finish_task_switch(struct rq *rq, struct task_struct *prev)
2411 __releases(rq->lock)
2413 struct mm_struct *mm = rq->prev_mm;
2419 * A task struct has one reference for the use as "current".
2420 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2421 * schedule one last time. The schedule call will never return, and
2422 * the scheduled task must drop that reference.
2423 * The test for TASK_DEAD must occur while the runqueue locks are
2424 * still held, otherwise prev could be scheduled on another cpu, die
2425 * there before we look at prev->state, and then the reference would
2427 * Manfred Spraul <manfred@colorfullife.com>
2429 prev_state = prev->state;
2430 finish_arch_switch(prev);
2431 finish_lock_switch(rq, prev);
2433 if (current->sched_class->post_schedule)
2434 current->sched_class->post_schedule(rq);
2437 fire_sched_in_preempt_notifiers(current);
2440 if (unlikely(prev_state == TASK_DEAD)) {
2442 * Remove function-return probe instances associated with this
2443 * task and put them back on the free list.
2445 kprobe_flush_task(prev);
2446 put_task_struct(prev);
2451 * schedule_tail - first thing a freshly forked thread must call.
2452 * @prev: the thread we just switched away from.
2454 asmlinkage void schedule_tail(struct task_struct *prev)
2455 __releases(rq->lock)
2457 struct rq *rq = this_rq();
2459 finish_task_switch(rq, prev);
2460 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2461 /* In this case, finish_task_switch does not reenable preemption */
2464 if (current->set_child_tid)
2465 put_user(task_pid_vnr(current), current->set_child_tid);
2469 * context_switch - switch to the new MM and the new
2470 * thread's register state.
2473 context_switch(struct rq *rq, struct task_struct *prev,
2474 struct task_struct *next)
2476 struct mm_struct *mm, *oldmm;
2478 prepare_task_switch(rq, prev, next);
2479 trace_mark(kernel_sched_schedule,
2480 "prev_pid %d next_pid %d prev_state %ld "
2481 "## rq %p prev %p next %p",
2482 prev->pid, next->pid, prev->state,
2485 oldmm = prev->active_mm;
2487 * For paravirt, this is coupled with an exit in switch_to to
2488 * combine the page table reload and the switch backend into
2491 arch_enter_lazy_cpu_mode();
2493 if (unlikely(!mm)) {
2494 next->active_mm = oldmm;
2495 atomic_inc(&oldmm->mm_count);
2496 enter_lazy_tlb(oldmm, next);
2498 switch_mm(oldmm, mm, next);
2500 if (unlikely(!prev->mm)) {
2501 prev->active_mm = NULL;
2502 rq->prev_mm = oldmm;
2505 * Since the runqueue lock will be released by the next
2506 * task (which is an invalid locking op but in the case
2507 * of the scheduler it's an obvious special-case), so we
2508 * do an early lockdep release here:
2510 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2511 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
2514 /* Here we just switch the register state and the stack. */
2515 switch_to(prev, next, prev);
2519 * this_rq must be evaluated again because prev may have moved
2520 * CPUs since it called schedule(), thus the 'rq' on its stack
2521 * frame will be invalid.
2523 finish_task_switch(this_rq(), prev);
2527 * nr_running, nr_uninterruptible and nr_context_switches:
2529 * externally visible scheduler statistics: current number of runnable
2530 * threads, current number of uninterruptible-sleeping threads, total
2531 * number of context switches performed since bootup.
2533 unsigned long nr_running(void)
2535 unsigned long i, sum = 0;
2537 for_each_online_cpu(i)
2538 sum += cpu_rq(i)->nr_running;
2543 unsigned long nr_uninterruptible(void)
2545 unsigned long i, sum = 0;
2547 for_each_possible_cpu(i)
2548 sum += cpu_rq(i)->nr_uninterruptible;
2551 * Since we read the counters lockless, it might be slightly
2552 * inaccurate. Do not allow it to go below zero though:
2554 if (unlikely((long)sum < 0))
2560 unsigned long long nr_context_switches(void)
2563 unsigned long long sum = 0;
2565 for_each_possible_cpu(i)
2566 sum += cpu_rq(i)->nr_switches;
2571 unsigned long nr_iowait(void)
2573 unsigned long i, sum = 0;
2575 for_each_possible_cpu(i)
2576 sum += atomic_read(&cpu_rq(i)->nr_iowait);
2581 unsigned long nr_active(void)
2583 unsigned long i, running = 0, uninterruptible = 0;
2585 for_each_online_cpu(i) {
2586 running += cpu_rq(i)->nr_running;
2587 uninterruptible += cpu_rq(i)->nr_uninterruptible;
2590 if (unlikely((long)uninterruptible < 0))
2591 uninterruptible = 0;
2593 return running + uninterruptible;
2597 * Update rq->cpu_load[] statistics. This function is usually called every
2598 * scheduler tick (TICK_NSEC).
2600 static void update_cpu_load(struct rq *this_rq)
2602 unsigned long this_load = this_rq->load.weight;
2605 this_rq->nr_load_updates++;
2607 /* Update our load: */
2608 for (i = 0, scale = 1; i < CPU_LOAD_IDX_MAX; i++, scale += scale) {
2609 unsigned long old_load, new_load;
2611 /* scale is effectively 1 << i now, and >> i divides by scale */
2613 old_load = this_rq->cpu_load[i];
2614 new_load = this_load;
2616 * Round up the averaging division if load is increasing. This
2617 * prevents us from getting stuck on 9 if the load is 10, for
2620 if (new_load > old_load)
2621 new_load += scale-1;
2622 this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) >> i;
2629 * double_rq_lock - safely lock two runqueues
2631 * Note this does not disable interrupts like task_rq_lock,
2632 * you need to do so manually before calling.
2634 static void double_rq_lock(struct rq *rq1, struct rq *rq2)
2635 __acquires(rq1->lock)
2636 __acquires(rq2->lock)
2638 BUG_ON(!irqs_disabled());
2640 spin_lock(&rq1->lock);
2641 __acquire(rq2->lock); /* Fake it out ;) */
2644 spin_lock(&rq1->lock);
2645 spin_lock(&rq2->lock);
2647 spin_lock(&rq2->lock);
2648 spin_lock(&rq1->lock);
2651 update_rq_clock(rq1);
2652 update_rq_clock(rq2);
2656 * double_rq_unlock - safely unlock two runqueues
2658 * Note this does not restore interrupts like task_rq_unlock,
2659 * you need to do so manually after calling.
2661 static void double_rq_unlock(struct rq *rq1, struct rq *rq2)
2662 __releases(rq1->lock)
2663 __releases(rq2->lock)
2665 spin_unlock(&rq1->lock);
2667 spin_unlock(&rq2->lock);
2669 __release(rq2->lock);
2673 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
2675 static int double_lock_balance(struct rq *this_rq, struct rq *busiest)
2676 __releases(this_rq->lock)
2677 __acquires(busiest->lock)
2678 __acquires(this_rq->lock)
2682 if (unlikely(!irqs_disabled())) {
2683 /* printk() doesn't work good under rq->lock */
2684 spin_unlock(&this_rq->lock);
2687 if (unlikely(!spin_trylock(&busiest->lock))) {
2688 if (busiest < this_rq) {
2689 spin_unlock(&this_rq->lock);
2690 spin_lock(&busiest->lock);
2691 spin_lock(&this_rq->lock);
2694 spin_lock(&busiest->lock);
2700 * If dest_cpu is allowed for this process, migrate the task to it.
2701 * This is accomplished by forcing the cpu_allowed mask to only
2702 * allow dest_cpu, which will force the cpu onto dest_cpu. Then
2703 * the cpu_allowed mask is restored.
2705 static void sched_migrate_task(struct task_struct *p, int dest_cpu)
2707 struct migration_req req;
2708 unsigned long flags;
2711 rq = task_rq_lock(p, &flags);
2712 if (!cpu_isset(dest_cpu, p->cpus_allowed)
2713 || unlikely(cpu_is_offline(dest_cpu)))
2716 /* force the process onto the specified CPU */
2717 if (migrate_task(p, dest_cpu, &req)) {
2718 /* Need to wait for migration thread (might exit: take ref). */
2719 struct task_struct *mt = rq->migration_thread;
2721 get_task_struct(mt);
2722 task_rq_unlock(rq, &flags);
2723 wake_up_process(mt);
2724 put_task_struct(mt);
2725 wait_for_completion(&req.done);
2730 task_rq_unlock(rq, &flags);
2734 * sched_exec - execve() is a valuable balancing opportunity, because at
2735 * this point the task has the smallest effective memory and cache footprint.
2737 void sched_exec(void)
2739 int new_cpu, this_cpu = get_cpu();
2740 new_cpu = sched_balance_self(this_cpu, SD_BALANCE_EXEC);
2742 if (new_cpu != this_cpu)
2743 sched_migrate_task(current, new_cpu);
2747 * pull_task - move a task from a remote runqueue to the local runqueue.
2748 * Both runqueues must be locked.
2750 static void pull_task(struct rq *src_rq, struct task_struct *p,
2751 struct rq *this_rq, int this_cpu)
2753 deactivate_task(src_rq, p, 0);
2754 set_task_cpu(p, this_cpu);
2755 activate_task(this_rq, p, 0);
2757 * Note that idle threads have a prio of MAX_PRIO, for this test
2758 * to be always true for them.
2760 check_preempt_curr(this_rq, p);
2764 * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
2767 int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu,
2768 struct sched_domain *sd, enum cpu_idle_type idle,
2772 * We do not migrate tasks that are:
2773 * 1) running (obviously), or
2774 * 2) cannot be migrated to this CPU due to cpus_allowed, or
2775 * 3) are cache-hot on their current CPU.
2777 if (!cpu_isset(this_cpu, p->cpus_allowed)) {
2778 schedstat_inc(p, se.nr_failed_migrations_affine);
2783 if (task_running(rq, p)) {
2784 schedstat_inc(p, se.nr_failed_migrations_running);
2789 * Aggressive migration if:
2790 * 1) task is cache cold, or
2791 * 2) too many balance attempts have failed.
2794 if (!task_hot(p, rq->clock, sd) ||
2795 sd->nr_balance_failed > sd->cache_nice_tries) {
2796 #ifdef CONFIG_SCHEDSTATS
2797 if (task_hot(p, rq->clock, sd)) {
2798 schedstat_inc(sd, lb_hot_gained[idle]);
2799 schedstat_inc(p, se.nr_forced_migrations);
2805 if (task_hot(p, rq->clock, sd)) {
2806 schedstat_inc(p, se.nr_failed_migrations_hot);
2812 static unsigned long
2813 balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
2814 unsigned long max_load_move, struct sched_domain *sd,
2815 enum cpu_idle_type idle, int *all_pinned,
2816 int *this_best_prio, struct rq_iterator *iterator)
2818 int loops = 0, pulled = 0, pinned = 0, skip_for_load;
2819 struct task_struct *p;
2820 long rem_load_move = max_load_move;
2822 if (max_load_move == 0)
2828 * Start the load-balancing iterator:
2830 p = iterator->start(iterator->arg);
2832 if (!p || loops++ > sysctl_sched_nr_migrate)
2835 * To help distribute high priority tasks across CPUs we don't
2836 * skip a task if it will be the highest priority task (i.e. smallest
2837 * prio value) on its new queue regardless of its load weight
2839 skip_for_load = (p->se.load.weight >> 1) > rem_load_move +
2840 SCHED_LOAD_SCALE_FUZZ;
2841 if ((skip_for_load && p->prio >= *this_best_prio) ||
2842 !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) {
2843 p = iterator->next(iterator->arg);
2847 pull_task(busiest, p, this_rq, this_cpu);
2849 rem_load_move -= p->se.load.weight;
2852 * We only want to steal up to the prescribed amount of weighted load.
2854 if (rem_load_move > 0) {
2855 if (p->prio < *this_best_prio)
2856 *this_best_prio = p->prio;
2857 p = iterator->next(iterator->arg);
2862 * Right now, this is one of only two places pull_task() is called,
2863 * so we can safely collect pull_task() stats here rather than
2864 * inside pull_task().
2866 schedstat_add(sd, lb_gained[idle], pulled);
2869 *all_pinned = pinned;
2871 return max_load_move - rem_load_move;
2875 * move_tasks tries to move up to max_load_move weighted load from busiest to
2876 * this_rq, as part of a balancing operation within domain "sd".
2877 * Returns 1 if successful and 0 otherwise.
2879 * Called with both runqueues locked.
2881 static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
2882 unsigned long max_load_move,
2883 struct sched_domain *sd, enum cpu_idle_type idle,
2886 const struct sched_class *class = sched_class_highest;
2887 unsigned long total_load_moved = 0;
2888 int this_best_prio = this_rq->curr->prio;
2892 class->load_balance(this_rq, this_cpu, busiest,
2893 max_load_move - total_load_moved,
2894 sd, idle, all_pinned, &this_best_prio);
2895 class = class->next;
2896 } while (class && max_load_move > total_load_moved);
2898 return total_load_moved > 0;
2902 iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
2903 struct sched_domain *sd, enum cpu_idle_type idle,
2904 struct rq_iterator *iterator)
2906 struct task_struct *p = iterator->start(iterator->arg);
2910 if (can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) {
2911 pull_task(busiest, p, this_rq, this_cpu);
2913 * Right now, this is only the second place pull_task()
2914 * is called, so we can safely collect pull_task()
2915 * stats here rather than inside pull_task().
2917 schedstat_inc(sd, lb_gained[idle]);
2921 p = iterator->next(iterator->arg);
2928 * move_one_task tries to move exactly one task from busiest to this_rq, as
2929 * part of active balancing operations within "domain".
2930 * Returns 1 if successful and 0 otherwise.
2932 * Called with both runqueues locked.
2934 static int move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
2935 struct sched_domain *sd, enum cpu_idle_type idle)
2937 const struct sched_class *class;
2939 for (class = sched_class_highest; class; class = class->next)
2940 if (class->move_one_task(this_rq, this_cpu, busiest, sd, idle))
2947 * find_busiest_group finds and returns the busiest CPU group within the
2948 * domain. It calculates and returns the amount of weighted load which
2949 * should be moved to restore balance via the imbalance parameter.
2951 static struct sched_group *
2952 find_busiest_group(struct sched_domain *sd, int this_cpu,
2953 unsigned long *imbalance, enum cpu_idle_type idle,
2954 int *sd_idle, const cpumask_t *cpus, int *balance)
2956 struct sched_group *busiest = NULL, *this = NULL, *group = sd->groups;
2957 unsigned long max_load, avg_load, total_load, this_load, total_pwr;
2958 unsigned long max_pull;
2959 unsigned long busiest_load_per_task, busiest_nr_running;
2960 unsigned long this_load_per_task, this_nr_running;
2961 int load_idx, group_imb = 0;
2962 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
2963 int power_savings_balance = 1;
2964 unsigned long leader_nr_running = 0, min_load_per_task = 0;
2965 unsigned long min_nr_running = ULONG_MAX;
2966 struct sched_group *group_min = NULL, *group_leader = NULL;
2969 max_load = this_load = total_load = total_pwr = 0;
2970 busiest_load_per_task = busiest_nr_running = 0;
2971 this_load_per_task = this_nr_running = 0;
2972 if (idle == CPU_NOT_IDLE)
2973 load_idx = sd->busy_idx;
2974 else if (idle == CPU_NEWLY_IDLE)
2975 load_idx = sd->newidle_idx;
2977 load_idx = sd->idle_idx;
2980 unsigned long load, group_capacity, max_cpu_load, min_cpu_load;
2983 int __group_imb = 0;
2984 unsigned int balance_cpu = -1, first_idle_cpu = 0;
2985 unsigned long sum_nr_running, sum_weighted_load;
2987 local_group = cpu_isset(this_cpu, group->cpumask);
2990 balance_cpu = first_cpu(group->cpumask);
2992 /* Tally up the load of all CPUs in the group */
2993 sum_weighted_load = sum_nr_running = avg_load = 0;
2995 min_cpu_load = ~0UL;
2997 for_each_cpu_mask(i, group->cpumask) {
3000 if (!cpu_isset(i, *cpus))
3005 if (*sd_idle && rq->nr_running)
3008 /* Bias balancing toward cpus of our domain */
3010 if (idle_cpu(i) && !first_idle_cpu) {
3015 load = target_load(i, load_idx);
3017 load = source_load(i, load_idx);
3018 if (load > max_cpu_load)
3019 max_cpu_load = load;
3020 if (min_cpu_load > load)
3021 min_cpu_load = load;
3025 sum_nr_running += rq->nr_running;
3026 sum_weighted_load += weighted_cpuload(i);
3030 * First idle cpu or the first cpu(busiest) in this sched group
3031 * is eligible for doing load balancing at this and above
3032 * domains. In the newly idle case, we will allow all the cpu's
3033 * to do the newly idle load balance.
3035 if (idle != CPU_NEWLY_IDLE && local_group &&
3036 balance_cpu != this_cpu && balance) {
3041 total_load += avg_load;
3042 total_pwr += group->__cpu_power;
3044 /* Adjust by relative CPU power of the group */
3045 avg_load = sg_div_cpu_power(group,
3046 avg_load * SCHED_LOAD_SCALE);
3048 if ((max_cpu_load - min_cpu_load) > SCHED_LOAD_SCALE)
3051 group_capacity = group->__cpu_power / SCHED_LOAD_SCALE;
3054 this_load = avg_load;
3056 this_nr_running = sum_nr_running;
3057 this_load_per_task = sum_weighted_load;
3058 } else if (avg_load > max_load &&
3059 (sum_nr_running > group_capacity || __group_imb)) {
3060 max_load = avg_load;
3062 busiest_nr_running = sum_nr_running;
3063 busiest_load_per_task = sum_weighted_load;
3064 group_imb = __group_imb;
3067 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3069 * Busy processors will not participate in power savings
3072 if (idle == CPU_NOT_IDLE ||
3073 !(sd->flags & SD_POWERSAVINGS_BALANCE))
3077 * If the local group is idle or completely loaded
3078 * no need to do power savings balance at this domain
3080 if (local_group && (this_nr_running >= group_capacity ||
3082 power_savings_balance = 0;
3085 * If a group is already running at full capacity or idle,
3086 * don't include that group in power savings calculations
3088 if (!power_savings_balance || sum_nr_running >= group_capacity
3093 * Calculate the group which has the least non-idle load.
3094 * This is the group from where we need to pick up the load
3097 if ((sum_nr_running < min_nr_running) ||
3098 (sum_nr_running == min_nr_running &&
3099 first_cpu(group->cpumask) <
3100 first_cpu(group_min->cpumask))) {
3102 min_nr_running = sum_nr_running;
3103 min_load_per_task = sum_weighted_load /
3108 * Calculate the group which is almost near its
3109 * capacity but still has some space to pick up some load
3110 * from other group and save more power
3112 if (sum_nr_running <= group_capacity - 1) {
3113 if (sum_nr_running > leader_nr_running ||
3114 (sum_nr_running == leader_nr_running &&
3115 first_cpu(group->cpumask) >
3116 first_cpu(group_leader->cpumask))) {
3117 group_leader = group;
3118 leader_nr_running = sum_nr_running;
3123 group = group->next;
3124 } while (group != sd->groups);
3126 if (!busiest || this_load >= max_load || busiest_nr_running == 0)
3129 avg_load = (SCHED_LOAD_SCALE * total_load) / total_pwr;
3131 if (this_load >= avg_load ||
3132 100*max_load <= sd->imbalance_pct*this_load)
3135 busiest_load_per_task /= busiest_nr_running;
3137 busiest_load_per_task = min(busiest_load_per_task, avg_load);
3140 * We're trying to get all the cpus to the average_load, so we don't
3141 * want to push ourselves above the average load, nor do we wish to
3142 * reduce the max loaded cpu below the average load, as either of these
3143 * actions would just result in more rebalancing later, and ping-pong
3144 * tasks around. Thus we look for the minimum possible imbalance.
3145 * Negative imbalances (*we* are more loaded than anyone else) will
3146 * be counted as no imbalance for these purposes -- we can't fix that
3147 * by pulling tasks to us. Be careful of negative numbers as they'll
3148 * appear as very large values with unsigned longs.
3150 if (max_load <= busiest_load_per_task)
3154 * In the presence of smp nice balancing, certain scenarios can have
3155 * max load less than avg load(as we skip the groups at or below
3156 * its cpu_power, while calculating max_load..)
3158 if (max_load < avg_load) {
3160 goto small_imbalance;
3163 /* Don't want to pull so many tasks that a group would go idle */
3164 max_pull = min(max_load - avg_load, max_load - busiest_load_per_task);
3166 /* How much load to actually move to equalise the imbalance */
3167 *imbalance = min(max_pull * busiest->__cpu_power,
3168 (avg_load - this_load) * this->__cpu_power)
3172 * if *imbalance is less than the average load per runnable task
3173 * there is no gaurantee that any tasks will be moved so we'll have
3174 * a think about bumping its value to force at least one task to be
3177 if (*imbalance < busiest_load_per_task) {
3178 unsigned long tmp, pwr_now, pwr_move;
3182 pwr_move = pwr_now = 0;
3184 if (this_nr_running) {
3185 this_load_per_task /= this_nr_running;
3186 if (busiest_load_per_task > this_load_per_task)
3189 this_load_per_task = SCHED_LOAD_SCALE;
3191 if (max_load - this_load + SCHED_LOAD_SCALE_FUZZ >=
3192 busiest_load_per_task * imbn) {
3193 *imbalance = busiest_load_per_task;
3198 * OK, we don't have enough imbalance to justify moving tasks,
3199 * however we may be able to increase total CPU power used by
3203 pwr_now += busiest->__cpu_power *
3204 min(busiest_load_per_task, max_load);
3205 pwr_now += this->__cpu_power *
3206 min(this_load_per_task, this_load);
3207 pwr_now /= SCHED_LOAD_SCALE;
3209 /* Amount of load we'd subtract */
3210 tmp = sg_div_cpu_power(busiest,
3211 busiest_load_per_task * SCHED_LOAD_SCALE);
3213 pwr_move += busiest->__cpu_power *
3214 min(busiest_load_per_task, max_load - tmp);
3216 /* Amount of load we'd add */
3217 if (max_load * busiest->__cpu_power <
3218 busiest_load_per_task * SCHED_LOAD_SCALE)
3219 tmp = sg_div_cpu_power(this,
3220 max_load * busiest->__cpu_power);
3222 tmp = sg_div_cpu_power(this,
3223 busiest_load_per_task * SCHED_LOAD_SCALE);
3224 pwr_move += this->__cpu_power *
3225 min(this_load_per_task, this_load + tmp);
3226 pwr_move /= SCHED_LOAD_SCALE;
3228 /* Move if we gain throughput */
3229 if (pwr_move > pwr_now)
3230 *imbalance = busiest_load_per_task;
3236 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3237 if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE))
3240 if (this == group_leader && group_leader != group_min) {
3241 *imbalance = min_load_per_task;
3251 * find_busiest_queue - find the busiest runqueue among the cpus in group.
3254 find_busiest_queue(struct sched_group *group, enum cpu_idle_type idle,
3255 unsigned long imbalance, const cpumask_t *cpus)
3257 struct rq *busiest = NULL, *rq;
3258 unsigned long max_load = 0;
3261 for_each_cpu_mask(i, group->cpumask) {
3264 if (!cpu_isset(i, *cpus))
3268 wl = weighted_cpuload(i);
3270 if (rq->nr_running == 1 && wl > imbalance)
3273 if (wl > max_load) {
3283 * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
3284 * so long as it is large enough.
3286 #define MAX_PINNED_INTERVAL 512
3289 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3290 * tasks if there is an imbalance.
3292 static int load_balance(int this_cpu, struct rq *this_rq,
3293 struct sched_domain *sd, enum cpu_idle_type idle,
3294 int *balance, cpumask_t *cpus)
3296 int ld_moved, all_pinned = 0, active_balance = 0, sd_idle = 0;
3297 struct sched_group *group;
3298 unsigned long imbalance;
3300 unsigned long flags;
3305 * When power savings policy is enabled for the parent domain, idle
3306 * sibling can pick up load irrespective of busy siblings. In this case,
3307 * let the state of idle sibling percolate up as CPU_IDLE, instead of
3308 * portraying it as CPU_NOT_IDLE.
3310 if (idle != CPU_NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER &&
3311 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
3314 schedstat_inc(sd, lb_count[idle]);
3317 group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle,
3324 schedstat_inc(sd, lb_nobusyg[idle]);
3328 busiest = find_busiest_queue(group, idle, imbalance, cpus);
3330 schedstat_inc(sd, lb_nobusyq[idle]);
3334 BUG_ON(busiest == this_rq);
3336 schedstat_add(sd, lb_imbalance[idle], imbalance);
3339 if (busiest->nr_running > 1) {
3341 * Attempt to move tasks. If find_busiest_group has found
3342 * an imbalance but busiest->nr_running <= 1, the group is
3343 * still unbalanced. ld_moved simply stays zero, so it is
3344 * correctly treated as an imbalance.
3346 local_irq_save(flags);
3347 double_rq_lock(this_rq, busiest);
3348 ld_moved = move_tasks(this_rq, this_cpu, busiest,
3349 imbalance, sd, idle, &all_pinned);
3350 double_rq_unlock(this_rq, busiest);
3351 local_irq_restore(flags);
3354 * some other cpu did the load balance for us.
3356 if (ld_moved && this_cpu != smp_processor_id())
3357 resched_cpu(this_cpu);
3359 /* All tasks on this runqueue were pinned by CPU affinity */
3360 if (unlikely(all_pinned)) {
3361 cpu_clear(cpu_of(busiest), *cpus);
3362 if (!cpus_empty(*cpus))
3369 schedstat_inc(sd, lb_failed[idle]);
3370 sd->nr_balance_failed++;
3372 if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) {
3374 spin_lock_irqsave(&busiest->lock, flags);
3376 /* don't kick the migration_thread, if the curr
3377 * task on busiest cpu can't be moved to this_cpu
3379 if (!cpu_isset(this_cpu, busiest->curr->cpus_allowed)) {
3380 spin_unlock_irqrestore(&busiest->lock, flags);
3382 goto out_one_pinned;
3385 if (!busiest->active_balance) {
3386 busiest->active_balance = 1;
3387 busiest->push_cpu = this_cpu;
3390 spin_unlock_irqrestore(&busiest->lock, flags);
3392 wake_up_process(busiest->migration_thread);
3395 * We've kicked active balancing, reset the failure
3398 sd->nr_balance_failed = sd->cache_nice_tries+1;
3401 sd->nr_balance_failed = 0;
3403 if (likely(!active_balance)) {
3404 /* We were unbalanced, so reset the balancing interval */
3405 sd->balance_interval = sd->min_interval;
3408 * If we've begun active balancing, start to back off. This
3409 * case may not be covered by the all_pinned logic if there
3410 * is only 1 task on the busy runqueue (because we don't call
3413 if (sd->balance_interval < sd->max_interval)
3414 sd->balance_interval *= 2;
3417 if (!ld_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
3418 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
3423 schedstat_inc(sd, lb_balanced[idle]);
3425 sd->nr_balance_failed = 0;
3428 /* tune up the balancing interval */
3429 if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) ||
3430 (sd->balance_interval < sd->max_interval))
3431 sd->balance_interval *= 2;
3433 if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
3434 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
3440 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3441 * tasks if there is an imbalance.
3443 * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE).
3444 * this_rq is locked.
3447 load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd,
3450 struct sched_group *group;
3451 struct rq *busiest = NULL;
3452 unsigned long imbalance;
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 IDLE, instead of
3463 * portraying it as CPU_NOT_IDLE.
3465 if (sd->flags & SD_SHARE_CPUPOWER &&
3466 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
3469 schedstat_inc(sd, lb_count[CPU_NEWLY_IDLE]);
3471 group = find_busiest_group(sd, this_cpu, &imbalance, CPU_NEWLY_IDLE,
3472 &sd_idle, cpus, NULL);
3474 schedstat_inc(sd, lb_nobusyg[CPU_NEWLY_IDLE]);
3478 busiest = find_busiest_queue(group, CPU_NEWLY_IDLE, imbalance, cpus);
3480 schedstat_inc(sd, lb_nobusyq[CPU_NEWLY_IDLE]);
3484 BUG_ON(busiest == this_rq);
3486 schedstat_add(sd, lb_imbalance[CPU_NEWLY_IDLE], imbalance);
3489 if (busiest->nr_running > 1) {
3490 /* Attempt to move tasks */
3491 double_lock_balance(this_rq, busiest);
3492 /* this_rq->clock is already updated */
3493 update_rq_clock(busiest);
3494 ld_moved = move_tasks(this_rq, this_cpu, busiest,
3495 imbalance, sd, CPU_NEWLY_IDLE,
3497 spin_unlock(&busiest->lock);
3499 if (unlikely(all_pinned)) {
3500 cpu_clear(cpu_of(busiest), *cpus);
3501 if (!cpus_empty(*cpus))
3507 schedstat_inc(sd, lb_failed[CPU_NEWLY_IDLE]);
3508 if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
3509 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
3512 sd->nr_balance_failed = 0;
3517 schedstat_inc(sd, lb_balanced[CPU_NEWLY_IDLE]);
3518 if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
3519 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
3521 sd->nr_balance_failed = 0;
3527 * idle_balance is called by schedule() if this_cpu is about to become
3528 * idle. Attempts to pull tasks from other CPUs.
3530 static void idle_balance(int this_cpu, struct rq *this_rq)
3532 struct sched_domain *sd;
3533 int pulled_task = -1;
3534 unsigned long next_balance = jiffies + HZ;
3537 for_each_domain(this_cpu, sd) {
3538 unsigned long interval;
3540 if (!(sd->flags & SD_LOAD_BALANCE))
3543 if (sd->flags & SD_BALANCE_NEWIDLE)
3544 /* If we've pulled tasks over stop searching: */
3545 pulled_task = load_balance_newidle(this_cpu, this_rq,
3548 interval = msecs_to_jiffies(sd->balance_interval);
3549 if (time_after(next_balance, sd->last_balance + interval))
3550 next_balance = sd->last_balance + interval;
3554 if (pulled_task || time_after(jiffies, this_rq->next_balance)) {
3556 * We are going idle. next_balance may be set based on
3557 * a busy processor. So reset next_balance.
3559 this_rq->next_balance = next_balance;
3564 * active_load_balance is run by migration threads. It pushes running tasks
3565 * off the busiest CPU onto idle CPUs. It requires at least 1 task to be
3566 * running on each physical CPU where possible, and avoids physical /
3567 * logical imbalances.
3569 * Called with busiest_rq locked.
3571 static void active_load_balance(struct rq *busiest_rq, int busiest_cpu)
3573 int target_cpu = busiest_rq->push_cpu;
3574 struct sched_domain *sd;
3575 struct rq *target_rq;
3577 /* Is there any task to move? */
3578 if (busiest_rq->nr_running <= 1)
3581 target_rq = cpu_rq(target_cpu);
3584 * This condition is "impossible", if it occurs
3585 * we need to fix it. Originally reported by
3586 * Bjorn Helgaas on a 128-cpu setup.
3588 BUG_ON(busiest_rq == target_rq);
3590 /* move a task from busiest_rq to target_rq */
3591 double_lock_balance(busiest_rq, target_rq);
3592 update_rq_clock(busiest_rq);
3593 update_rq_clock(target_rq);
3595 /* Search for an sd spanning us and the target CPU. */
3596 for_each_domain(target_cpu, sd) {
3597 if ((sd->flags & SD_LOAD_BALANCE) &&
3598 cpu_isset(busiest_cpu, sd->span))
3603 schedstat_inc(sd, alb_count);
3605 if (move_one_task(target_rq, target_cpu, busiest_rq,
3607 schedstat_inc(sd, alb_pushed);
3609 schedstat_inc(sd, alb_failed);
3611 spin_unlock(&target_rq->lock);
3616 atomic_t load_balancer;
3618 } nohz ____cacheline_aligned = {
3619 .load_balancer = ATOMIC_INIT(-1),
3620 .cpu_mask = CPU_MASK_NONE,
3624 * This routine will try to nominate the ilb (idle load balancing)
3625 * owner among the cpus whose ticks are stopped. ilb owner will do the idle
3626 * load balancing on behalf of all those cpus. If all the cpus in the system
3627 * go into this tickless mode, then there will be no ilb owner (as there is
3628 * no need for one) and all the cpus will sleep till the next wakeup event
3631 * For the ilb owner, tick is not stopped. And this tick will be used
3632 * for idle load balancing. ilb owner will still be part of
3635 * While stopping the tick, this cpu will become the ilb owner if there
3636 * is no other owner. And will be the owner till that cpu becomes busy
3637 * or if all cpus in the system stop their ticks at which point
3638 * there is no need for ilb owner.
3640 * When the ilb owner becomes busy, it nominates another owner, during the
3641 * next busy scheduler_tick()
3643 int select_nohz_load_balancer(int stop_tick)
3645 int cpu = smp_processor_id();
3648 cpu_set(cpu, nohz.cpu_mask);
3649 cpu_rq(cpu)->in_nohz_recently = 1;
3652 * If we are going offline and still the leader, give up!
3654 if (cpu_is_offline(cpu) &&
3655 atomic_read(&nohz.load_balancer) == cpu) {
3656 if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu)
3661 /* time for ilb owner also to sleep */
3662 if (cpus_weight(nohz.cpu_mask) == num_online_cpus()) {
3663 if (atomic_read(&nohz.load_balancer) == cpu)
3664 atomic_set(&nohz.load_balancer, -1);
3668 if (atomic_read(&nohz.load_balancer) == -1) {
3669 /* make me the ilb owner */
3670 if (atomic_cmpxchg(&nohz.load_balancer, -1, cpu) == -1)
3672 } else if (atomic_read(&nohz.load_balancer) == cpu)
3675 if (!cpu_isset(cpu, nohz.cpu_mask))
3678 cpu_clear(cpu, nohz.cpu_mask);
3680 if (atomic_read(&nohz.load_balancer) == cpu)
3681 if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu)
3688 static DEFINE_SPINLOCK(balancing);
3691 * It checks each scheduling domain to see if it is due to be balanced,
3692 * and initiates a balancing operation if so.
3694 * Balancing parameters are set up in arch_init_sched_domains.
3696 static void rebalance_domains(int cpu, enum cpu_idle_type idle)
3699 struct rq *rq = cpu_rq(cpu);
3700 unsigned long interval;
3701 struct sched_domain *sd;
3702 /* Earliest time when we have to do rebalance again */
3703 unsigned long next_balance = jiffies + 60*HZ;
3704 int update_next_balance = 0;
3707 for_each_domain(cpu, sd) {
3708 if (!(sd->flags & SD_LOAD_BALANCE))
3711 interval = sd->balance_interval;
3712 if (idle != CPU_IDLE)
3713 interval *= sd->busy_factor;
3715 /* scale ms to jiffies */
3716 interval = msecs_to_jiffies(interval);
3717 if (unlikely(!interval))
3719 if (interval > HZ*NR_CPUS/10)
3720 interval = HZ*NR_CPUS/10;
3723 if (sd->flags & SD_SERIALIZE) {
3724 if (!spin_trylock(&balancing))
3728 if (time_after_eq(jiffies, sd->last_balance + interval)) {
3729 if (load_balance(cpu, rq, sd, idle, &balance, &tmp)) {
3731 * We've pulled tasks over so either we're no
3732 * longer idle, or one of our SMT siblings is
3735 idle = CPU_NOT_IDLE;
3737 sd->last_balance = jiffies;
3739 if (sd->flags & SD_SERIALIZE)
3740 spin_unlock(&balancing);
3742 if (time_after(next_balance, sd->last_balance + interval)) {
3743 next_balance = sd->last_balance + interval;
3744 update_next_balance = 1;
3748 * Stop the load balance at this level. There is another
3749 * CPU in our sched group which is doing load balancing more
3757 * next_balance will be updated only when there is a need.
3758 * When the cpu is attached to null domain for ex, it will not be
3761 if (likely(update_next_balance))
3762 rq->next_balance = next_balance;
3766 * run_rebalance_domains is triggered when needed from the scheduler tick.
3767 * In CONFIG_NO_HZ case, the idle load balance owner will do the
3768 * rebalancing for all the cpus for whom scheduler ticks are stopped.
3770 static void run_rebalance_domains(struct softirq_action *h)
3772 int this_cpu = smp_processor_id();
3773 struct rq *this_rq = cpu_rq(this_cpu);
3774 enum cpu_idle_type idle = this_rq->idle_at_tick ?
3775 CPU_IDLE : CPU_NOT_IDLE;
3777 rebalance_domains(this_cpu, idle);
3781 * If this cpu is the owner for idle load balancing, then do the
3782 * balancing on behalf of the other idle cpus whose ticks are
3785 if (this_rq->idle_at_tick &&
3786 atomic_read(&nohz.load_balancer) == this_cpu) {
3787 cpumask_t cpus = nohz.cpu_mask;
3791 cpu_clear(this_cpu, cpus);
3792 for_each_cpu_mask(balance_cpu, cpus) {
3794 * If this cpu gets work to do, stop the load balancing
3795 * work being done for other cpus. Next load
3796 * balancing owner will pick it up.
3801 rebalance_domains(balance_cpu, CPU_IDLE);
3803 rq = cpu_rq(balance_cpu);
3804 if (time_after(this_rq->next_balance, rq->next_balance))
3805 this_rq->next_balance = rq->next_balance;
3812 * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
3814 * In case of CONFIG_NO_HZ, this is the place where we nominate a new
3815 * idle load balancing owner or decide to stop the periodic load balancing,
3816 * if the whole system is idle.
3818 static inline void trigger_load_balance(struct rq *rq, int cpu)
3822 * If we were in the nohz mode recently and busy at the current
3823 * scheduler tick, then check if we need to nominate new idle
3826 if (rq->in_nohz_recently && !rq->idle_at_tick) {
3827 rq->in_nohz_recently = 0;
3829 if (atomic_read(&nohz.load_balancer) == cpu) {
3830 cpu_clear(cpu, nohz.cpu_mask);
3831 atomic_set(&nohz.load_balancer, -1);
3834 if (atomic_read(&nohz.load_balancer) == -1) {
3836 * simple selection for now: Nominate the
3837 * first cpu in the nohz list to be the next
3840 * TBD: Traverse the sched domains and nominate
3841 * the nearest cpu in the nohz.cpu_mask.
3843 int ilb = first_cpu(nohz.cpu_mask);
3845 if (ilb < nr_cpu_ids)
3851 * If this cpu is idle and doing idle load balancing for all the
3852 * cpus with ticks stopped, is it time for that to stop?
3854 if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) == cpu &&
3855 cpus_weight(nohz.cpu_mask) == num_online_cpus()) {
3861 * If this cpu is idle and the idle load balancing is done by
3862 * someone else, then no need raise the SCHED_SOFTIRQ
3864 if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) != cpu &&
3865 cpu_isset(cpu, nohz.cpu_mask))
3868 if (time_after_eq(jiffies, rq->next_balance))
3869 raise_softirq(SCHED_SOFTIRQ);
3872 #else /* CONFIG_SMP */
3875 * on UP we do not need to balance between CPUs:
3877 static inline void idle_balance(int cpu, struct rq *rq)
3883 DEFINE_PER_CPU(struct kernel_stat, kstat);
3885 EXPORT_PER_CPU_SYMBOL(kstat);
3888 * Return p->sum_exec_runtime plus any more ns on the sched_clock
3889 * that have not yet been banked in case the task is currently running.
3891 unsigned long long task_sched_runtime(struct task_struct *p)
3893 unsigned long flags;
3897 rq = task_rq_lock(p, &flags);
3898 ns = p->se.sum_exec_runtime;
3899 if (task_current(rq, p)) {
3900 update_rq_clock(rq);
3901 delta_exec = rq->clock - p->se.exec_start;
3902 if ((s64)delta_exec > 0)
3905 task_rq_unlock(rq, &flags);
3911 * Account user cpu time to a process.
3912 * @p: the process that the cpu time gets accounted to
3913 * @cputime: the cpu time spent in user space since the last update
3915 void account_user_time(struct task_struct *p, cputime_t cputime)
3917 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
3920 p->utime = cputime_add(p->utime, cputime);
3922 /* Add user time to cpustat. */
3923 tmp = cputime_to_cputime64(cputime);
3924 if (TASK_NICE(p) > 0)
3925 cpustat->nice = cputime64_add(cpustat->nice, tmp);
3927 cpustat->user = cputime64_add(cpustat->user, tmp);
3931 * Account guest cpu time to a process.
3932 * @p: the process that the cpu time gets accounted to
3933 * @cputime: the cpu time spent in virtual machine since the last update
3935 static void account_guest_time(struct task_struct *p, cputime_t cputime)
3938 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
3940 tmp = cputime_to_cputime64(cputime);
3942 p->utime = cputime_add(p->utime, cputime);
3943 p->gtime = cputime_add(p->gtime, cputime);
3945 cpustat->user = cputime64_add(cpustat->user, tmp);
3946 cpustat->guest = cputime64_add(cpustat->guest, tmp);
3950 * Account scaled user cpu time to a process.
3951 * @p: the process that the cpu time gets accounted to
3952 * @cputime: the cpu time spent in user space since the last update
3954 void account_user_time_scaled(struct task_struct *p, cputime_t cputime)
3956 p->utimescaled = cputime_add(p->utimescaled, cputime);
3960 * Account system cpu time to a process.
3961 * @p: the process that the cpu time gets accounted to
3962 * @hardirq_offset: the offset to subtract from hardirq_count()
3963 * @cputime: the cpu time spent in kernel space since the last update
3965 void account_system_time(struct task_struct *p, int hardirq_offset,
3968 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
3969 struct rq *rq = this_rq();
3972 if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
3973 account_guest_time(p, cputime);
3977 p->stime = cputime_add(p->stime, cputime);
3979 /* Add system time to cpustat. */
3980 tmp = cputime_to_cputime64(cputime);
3981 if (hardirq_count() - hardirq_offset)
3982 cpustat->irq = cputime64_add(cpustat->irq, tmp);
3983 else if (softirq_count())
3984 cpustat->softirq = cputime64_add(cpustat->softirq, tmp);
3985 else if (p != rq->idle)
3986 cpustat->system = cputime64_add(cpustat->system, tmp);
3987 else if (atomic_read(&rq->nr_iowait) > 0)
3988 cpustat->iowait = cputime64_add(cpustat->iowait, tmp);
3990 cpustat->idle = cputime64_add(cpustat->idle, tmp);
3991 /* Account for system time used */
3992 acct_update_integrals(p);
3996 * Account scaled system cpu time to a process.
3997 * @p: the process that the cpu time gets accounted to
3998 * @hardirq_offset: the offset to subtract from hardirq_count()
3999 * @cputime: the cpu time spent in kernel space since the last update
4001 void account_system_time_scaled(struct task_struct *p, cputime_t cputime)
4003 p->stimescaled = cputime_add(p->stimescaled, cputime);
4007 * Account for involuntary wait time.
4008 * @p: the process from which the cpu time has been stolen
4009 * @steal: the cpu time spent in involuntary wait
4011 void account_steal_time(struct task_struct *p, cputime_t steal)
4013 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
4014 cputime64_t tmp = cputime_to_cputime64(steal);
4015 struct rq *rq = this_rq();
4017 if (p == rq->idle) {
4018 p->stime = cputime_add(p->stime, steal);
4019 if (atomic_read(&rq->nr_iowait) > 0)
4020 cpustat->iowait = cputime64_add(cpustat->iowait, tmp);
4022 cpustat->idle = cputime64_add(cpustat->idle, tmp);
4024 cpustat->steal = cputime64_add(cpustat->steal, tmp);
4028 * This function gets called by the timer code, with HZ frequency.
4029 * We call it with interrupts disabled.
4031 * It also gets called by the fork code, when changing the parent's
4034 void scheduler_tick(void)
4036 int cpu = smp_processor_id();
4037 struct rq *rq = cpu_rq(cpu);
4038 struct task_struct *curr = rq->curr;
4042 spin_lock(&rq->lock);
4043 update_rq_clock(rq);
4044 update_cpu_load(rq);
4045 curr->sched_class->task_tick(rq, curr, 0);
4046 spin_unlock(&rq->lock);
4049 rq->idle_at_tick = idle_cpu(cpu);
4050 trigger_load_balance(rq, cpu);
4054 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
4055 defined(CONFIG_PREEMPT_TRACER))
4057 static inline unsigned long get_parent_ip(unsigned long addr)
4059 if (in_lock_functions(addr)) {
4060 addr = CALLER_ADDR2;
4061 if (in_lock_functions(addr))
4062 addr = CALLER_ADDR3;
4067 void __kprobes add_preempt_count(int val)
4069 #ifdef CONFIG_DEBUG_PREEMPT
4073 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
4076 preempt_count() += val;
4077 #ifdef CONFIG_DEBUG_PREEMPT
4079 * Spinlock count overflowing soon?
4081 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
4084 if (preempt_count() == val)
4085 trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
4087 EXPORT_SYMBOL(add_preempt_count);
4089 void __kprobes sub_preempt_count(int val)
4091 #ifdef CONFIG_DEBUG_PREEMPT
4095 if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
4098 * Is the spinlock portion underflowing?
4100 if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
4101 !(preempt_count() & PREEMPT_MASK)))
4105 if (preempt_count() == val)
4106 trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
4107 preempt_count() -= val;
4109 EXPORT_SYMBOL(sub_preempt_count);
4114 * Print scheduling while atomic bug:
4116 static noinline void __schedule_bug(struct task_struct *prev)
4118 struct pt_regs *regs = get_irq_regs();
4120 printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
4121 prev->comm, prev->pid, preempt_count());
4123 debug_show_held_locks(prev);
4124 if (irqs_disabled())
4125 print_irqtrace_events(prev);
4134 * Various schedule()-time debugging checks and statistics:
4136 static inline void schedule_debug(struct task_struct *prev)
4139 * Test if we are atomic. Since do_exit() needs to call into
4140 * schedule() atomically, we ignore that path for now.
4141 * Otherwise, whine if we are scheduling when we should not be.
4143 if (unlikely(in_atomic_preempt_off() && !prev->exit_state))
4144 __schedule_bug(prev);
4146 profile_hit(SCHED_PROFILING, __builtin_return_address(0));
4148 schedstat_inc(this_rq(), sched_count);
4149 #ifdef CONFIG_SCHEDSTATS
4150 if (unlikely(prev->lock_depth >= 0)) {
4151 schedstat_inc(this_rq(), bkl_count);
4152 schedstat_inc(prev, sched_info.bkl_count);
4158 * Pick up the highest-prio task:
4160 static inline struct task_struct *
4161 pick_next_task(struct rq *rq, struct task_struct *prev)
4163 const struct sched_class *class;
4164 struct task_struct *p;
4167 * Optimization: we know that if all tasks are in
4168 * the fair class we can call that function directly:
4170 if (likely(rq->nr_running == rq->cfs.nr_running)) {
4171 p = fair_sched_class.pick_next_task(rq);
4176 class = sched_class_highest;
4178 p = class->pick_next_task(rq);
4182 * Will never be NULL as the idle class always
4183 * returns a non-NULL p:
4185 class = class->next;
4190 * schedule() is the main scheduler function.
4192 asmlinkage void __sched schedule(void)
4194 struct task_struct *prev, *next;
4195 unsigned long *switch_count;
4201 cpu = smp_processor_id();
4205 switch_count = &prev->nivcsw;
4207 release_kernel_lock(prev);
4208 need_resched_nonpreemptible:
4210 schedule_debug(prev);
4215 * Do the rq-clock update outside the rq lock:
4217 local_irq_disable();
4218 update_rq_clock(rq);
4219 spin_lock(&rq->lock);
4220 clear_tsk_need_resched(prev);
4222 if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
4223 if (unlikely(signal_pending_state(prev->state, prev)))
4224 prev->state = TASK_RUNNING;
4226 deactivate_task(rq, prev, 1);
4227 switch_count = &prev->nvcsw;
4231 if (prev->sched_class->pre_schedule)
4232 prev->sched_class->pre_schedule(rq, prev);
4235 if (unlikely(!rq->nr_running))
4236 idle_balance(cpu, rq);
4238 prev->sched_class->put_prev_task(rq, prev);
4239 next = pick_next_task(rq, prev);
4241 if (likely(prev != next)) {
4242 sched_info_switch(prev, next);
4248 context_switch(rq, prev, next); /* unlocks the rq */
4250 * the context switch might have flipped the stack from under
4251 * us, hence refresh the local variables.
4253 cpu = smp_processor_id();
4256 spin_unlock_irq(&rq->lock);
4260 if (unlikely(reacquire_kernel_lock(current) < 0))
4261 goto need_resched_nonpreemptible;
4263 preempt_enable_no_resched();
4264 if (unlikely(test_thread_flag(TIF_NEED_RESCHED)))
4267 EXPORT_SYMBOL(schedule);
4269 #ifdef CONFIG_PREEMPT
4271 * this is the entry point to schedule() from in-kernel preemption
4272 * off of preempt_enable. Kernel preemptions off return from interrupt
4273 * occur there and call schedule directly.
4275 asmlinkage void __sched preempt_schedule(void)
4277 struct thread_info *ti = current_thread_info();
4280 * If there is a non-zero preempt_count or interrupts are disabled,
4281 * we do not want to preempt the current task. Just return..
4283 if (likely(ti->preempt_count || irqs_disabled()))
4287 add_preempt_count(PREEMPT_ACTIVE);
4289 sub_preempt_count(PREEMPT_ACTIVE);
4292 * Check again in case we missed a preemption opportunity
4293 * between schedule and now.
4296 } while (unlikely(test_thread_flag(TIF_NEED_RESCHED)));
4298 EXPORT_SYMBOL(preempt_schedule);
4301 * this is the entry point to schedule() from kernel preemption
4302 * off of irq context.
4303 * Note, that this is called and return with irqs disabled. This will
4304 * protect us against recursive calling from irq.
4306 asmlinkage void __sched preempt_schedule_irq(void)
4308 struct thread_info *ti = current_thread_info();
4310 /* Catch callers which need to be fixed */
4311 BUG_ON(ti->preempt_count || !irqs_disabled());
4314 add_preempt_count(PREEMPT_ACTIVE);
4317 local_irq_disable();
4318 sub_preempt_count(PREEMPT_ACTIVE);
4321 * Check again in case we missed a preemption opportunity
4322 * between schedule and now.
4325 } while (unlikely(test_thread_flag(TIF_NEED_RESCHED)));
4328 #endif /* CONFIG_PREEMPT */
4330 int default_wake_function(wait_queue_t *curr, unsigned mode, int sync,
4333 return try_to_wake_up(curr->private, mode, sync);
4335 EXPORT_SYMBOL(default_wake_function);
4338 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
4339 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
4340 * number) then we wake all the non-exclusive tasks and one exclusive task.
4342 * There are circumstances in which we can try to wake a task which has already
4343 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
4344 * zero in this (rare) case, and we handle it by continuing to scan the queue.
4346 static void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
4347 int nr_exclusive, int sync, void *key)
4349 wait_queue_t *curr, *next;
4351 list_for_each_entry_safe(curr, next, &q->task_list, task_list) {
4352 unsigned flags = curr->flags;
4354 if (curr->func(curr, mode, sync, key) &&
4355 (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive)
4361 * __wake_up - wake up threads blocked on a waitqueue.
4363 * @mode: which threads
4364 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4365 * @key: is directly passed to the wakeup function
4367 void __wake_up(wait_queue_head_t *q, unsigned int mode,
4368 int nr_exclusive, void *key)
4370 unsigned long flags;
4372 spin_lock_irqsave(&q->lock, flags);
4373 __wake_up_common(q, mode, nr_exclusive, 0, key);
4374 spin_unlock_irqrestore(&q->lock, flags);
4376 EXPORT_SYMBOL(__wake_up);
4379 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
4381 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode)
4383 __wake_up_common(q, mode, 1, 0, NULL);
4387 * __wake_up_sync - wake up threads blocked on a waitqueue.
4389 * @mode: which threads
4390 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4392 * The sync wakeup differs that the waker knows that it will schedule
4393 * away soon, so while the target thread will be woken up, it will not
4394 * be migrated to another CPU - ie. the two threads are 'synchronized'
4395 * with each other. This can prevent needless bouncing between CPUs.
4397 * On UP it can prevent extra preemption.
4400 __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
4402 unsigned long flags;
4408 if (unlikely(!nr_exclusive))
4411 spin_lock_irqsave(&q->lock, flags);
4412 __wake_up_common(q, mode, nr_exclusive, sync, NULL);
4413 spin_unlock_irqrestore(&q->lock, flags);
4415 EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */
4417 void complete(struct completion *x)
4419 unsigned long flags;
4421 spin_lock_irqsave(&x->wait.lock, flags);
4423 __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL);
4424 spin_unlock_irqrestore(&x->wait.lock, flags);
4426 EXPORT_SYMBOL(complete);
4428 void complete_all(struct completion *x)
4430 unsigned long flags;
4432 spin_lock_irqsave(&x->wait.lock, flags);
4433 x->done += UINT_MAX/2;
4434 __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL);
4435 spin_unlock_irqrestore(&x->wait.lock, flags);
4437 EXPORT_SYMBOL(complete_all);
4439 static inline long __sched
4440 do_wait_for_common(struct completion *x, long timeout, int state)
4443 DECLARE_WAITQUEUE(wait, current);
4445 wait.flags |= WQ_FLAG_EXCLUSIVE;
4446 __add_wait_queue_tail(&x->wait, &wait);
4448 if ((state == TASK_INTERRUPTIBLE &&
4449 signal_pending(current)) ||
4450 (state == TASK_KILLABLE &&
4451 fatal_signal_pending(current))) {
4452 timeout = -ERESTARTSYS;
4455 __set_current_state(state);
4456 spin_unlock_irq(&x->wait.lock);
4457 timeout = schedule_timeout(timeout);
4458 spin_lock_irq(&x->wait.lock);
4459 } while (!x->done && timeout);
4460 __remove_wait_queue(&x->wait, &wait);
4465 return timeout ?: 1;
4469 wait_for_common(struct completion *x, long timeout, int state)
4473 spin_lock_irq(&x->wait.lock);
4474 timeout = do_wait_for_common(x, timeout, state);
4475 spin_unlock_irq(&x->wait.lock);
4479 void __sched wait_for_completion(struct completion *x)
4481 wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE);
4483 EXPORT_SYMBOL(wait_for_completion);
4485 unsigned long __sched
4486 wait_for_completion_timeout(struct completion *x, unsigned long timeout)
4488 return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE);
4490 EXPORT_SYMBOL(wait_for_completion_timeout);
4492 int __sched wait_for_completion_interruptible(struct completion *x)
4494 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE);
4495 if (t == -ERESTARTSYS)
4499 EXPORT_SYMBOL(wait_for_completion_interruptible);
4501 unsigned long __sched
4502 wait_for_completion_interruptible_timeout(struct completion *x,
4503 unsigned long timeout)
4505 return wait_for_common(x, timeout, TASK_INTERRUPTIBLE);
4507 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout);
4509 int __sched wait_for_completion_killable(struct completion *x)
4511 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE);
4512 if (t == -ERESTARTSYS)
4516 EXPORT_SYMBOL(wait_for_completion_killable);
4519 sleep_on_common(wait_queue_head_t *q, int state, long timeout)
4521 unsigned long flags;
4524 init_waitqueue_entry(&wait, current);
4526 __set_current_state(state);
4528 spin_lock_irqsave(&q->lock, flags);
4529 __add_wait_queue(q, &wait);
4530 spin_unlock(&q->lock);
4531 timeout = schedule_timeout(timeout);
4532 spin_lock_irq(&q->lock);
4533 __remove_wait_queue(q, &wait);
4534 spin_unlock_irqrestore(&q->lock, flags);
4539 void __sched interruptible_sleep_on(wait_queue_head_t *q)
4541 sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
4543 EXPORT_SYMBOL(interruptible_sleep_on);
4546 interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout)
4548 return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout);
4550 EXPORT_SYMBOL(interruptible_sleep_on_timeout);
4552 void __sched sleep_on(wait_queue_head_t *q)
4554 sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
4556 EXPORT_SYMBOL(sleep_on);
4558 long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout)
4560 return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout);
4562 EXPORT_SYMBOL(sleep_on_timeout);
4564 #ifdef CONFIG_RT_MUTEXES
4567 * rt_mutex_setprio - set the current priority of a task
4569 * @prio: prio value (kernel-internal form)
4571 * This function changes the 'effective' priority of a task. It does
4572 * not touch ->normal_prio like __setscheduler().
4574 * Used by the rt_mutex code to implement priority inheritance logic.
4576 void rt_mutex_setprio(struct task_struct *p, int prio)
4578 unsigned long flags;
4579 int oldprio, on_rq, running;
4581 const struct sched_class *prev_class = p->sched_class;
4583 BUG_ON(prio < 0 || prio > MAX_PRIO);
4585 rq = task_rq_lock(p, &flags);
4586 update_rq_clock(rq);
4589 on_rq = p->se.on_rq;
4590 running = task_current(rq, p);
4592 dequeue_task(rq, p, 0);
4594 p->sched_class->put_prev_task(rq, p);
4597 p->sched_class = &rt_sched_class;
4599 p->sched_class = &fair_sched_class;
4604 p->sched_class->set_curr_task(rq);
4606 enqueue_task(rq, p, 0);
4608 check_class_changed(rq, p, prev_class, oldprio, running);
4610 task_rq_unlock(rq, &flags);
4615 void set_user_nice(struct task_struct *p, long nice)
4617 int old_prio, delta, on_rq;
4618 unsigned long flags;
4621 if (TASK_NICE(p) == nice || nice < -20 || nice > 19)
4624 * We have to be careful, if called from sys_setpriority(),
4625 * the task might be in the middle of scheduling on another CPU.
4627 rq = task_rq_lock(p, &flags);
4628 update_rq_clock(rq);
4630 * The RT priorities are set via sched_setscheduler(), but we still
4631 * allow the 'normal' nice value to be set - but as expected
4632 * it wont have any effect on scheduling until the task is
4633 * SCHED_FIFO/SCHED_RR:
4635 if (task_has_rt_policy(p)) {
4636 p->static_prio = NICE_TO_PRIO(nice);
4639 on_rq = p->se.on_rq;
4641 dequeue_task(rq, p, 0);
4645 p->static_prio = NICE_TO_PRIO(nice);
4648 p->prio = effective_prio(p);
4649 delta = p->prio - old_prio;
4652 enqueue_task(rq, p, 0);
4655 * If the task increased its priority or is running and
4656 * lowered its priority, then reschedule its CPU:
4658 if (delta < 0 || (delta > 0 && task_running(rq, p)))
4659 resched_task(rq->curr);
4662 task_rq_unlock(rq, &flags);
4664 EXPORT_SYMBOL(set_user_nice);
4667 * can_nice - check if a task can reduce its nice value
4671 int can_nice(const struct task_struct *p, const int nice)
4673 /* convert nice value [19,-20] to rlimit style value [1,40] */
4674 int nice_rlim = 20 - nice;
4676 return (nice_rlim <= p->signal->rlim[RLIMIT_NICE].rlim_cur ||
4677 capable(CAP_SYS_NICE));
4680 #ifdef __ARCH_WANT_SYS_NICE
4683 * sys_nice - change the priority of the current process.
4684 * @increment: priority increment
4686 * sys_setpriority is a more generic, but much slower function that
4687 * does similar things.
4689 asmlinkage long sys_nice(int increment)
4694 * Setpriority might change our priority at the same moment.
4695 * We don't have to worry. Conceptually one call occurs first
4696 * and we have a single winner.
4698 if (increment < -40)
4703 nice = PRIO_TO_NICE(current->static_prio) + increment;
4709 if (increment < 0 && !can_nice(current, nice))
4712 retval = security_task_setnice(current, nice);
4716 set_user_nice(current, nice);
4723 * task_prio - return the priority value of a given task.
4724 * @p: the task in question.
4726 * This is the priority value as seen by users in /proc.
4727 * RT tasks are offset by -200. Normal tasks are centered
4728 * around 0, value goes from -16 to +15.
4730 int task_prio(const struct task_struct *p)
4732 return p->prio - MAX_RT_PRIO;
4736 * task_nice - return the nice value of a given task.
4737 * @p: the task in question.
4739 int task_nice(const struct task_struct *p)
4741 return TASK_NICE(p);
4743 EXPORT_SYMBOL(task_nice);
4746 * idle_cpu - is a given cpu idle currently?
4747 * @cpu: the processor in question.
4749 int idle_cpu(int cpu)
4751 return cpu_curr(cpu) == cpu_rq(cpu)->idle;
4755 * idle_task - return the idle task for a given cpu.
4756 * @cpu: the processor in question.
4758 struct task_struct *idle_task(int cpu)
4760 return cpu_rq(cpu)->idle;
4764 * find_process_by_pid - find a process with a matching PID value.
4765 * @pid: the pid in question.
4767 static struct task_struct *find_process_by_pid(pid_t pid)
4769 return pid ? find_task_by_vpid(pid) : current;
4772 /* Actually do priority change: must hold rq lock. */
4774 __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio)
4776 BUG_ON(p->se.on_rq);
4779 switch (p->policy) {
4783 p->sched_class = &fair_sched_class;
4787 p->sched_class = &rt_sched_class;
4791 p->rt_priority = prio;
4792 p->normal_prio = normal_prio(p);
4793 /* we are holding p->pi_lock already */
4794 p->prio = rt_mutex_getprio(p);
4799 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
4800 * @p: the task in question.
4801 * @policy: new policy.
4802 * @param: structure containing the new RT priority.
4804 * NOTE that the task may be already dead.
4806 int sched_setscheduler(struct task_struct *p, int policy,
4807 struct sched_param *param)
4809 int retval, oldprio, oldpolicy = -1, on_rq, running;
4810 unsigned long flags;
4811 const struct sched_class *prev_class = p->sched_class;
4814 /* may grab non-irq protected spin_locks */
4815 BUG_ON(in_interrupt());
4817 /* double check policy once rq lock held */
4819 policy = oldpolicy = p->policy;
4820 else if (policy != SCHED_FIFO && policy != SCHED_RR &&
4821 policy != SCHED_NORMAL && policy != SCHED_BATCH &&
4822 policy != SCHED_IDLE)
4825 * Valid priorities for SCHED_FIFO and SCHED_RR are
4826 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
4827 * SCHED_BATCH and SCHED_IDLE is 0.
4829 if (param->sched_priority < 0 ||
4830 (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) ||
4831 (!p->mm && param->sched_priority > MAX_RT_PRIO-1))
4833 if (rt_policy(policy) != (param->sched_priority != 0))
4837 * Allow unprivileged RT tasks to decrease priority:
4839 if (!capable(CAP_SYS_NICE)) {
4840 if (rt_policy(policy)) {
4841 unsigned long rlim_rtprio;
4843 if (!lock_task_sighand(p, &flags))
4845 rlim_rtprio = p->signal->rlim[RLIMIT_RTPRIO].rlim_cur;
4846 unlock_task_sighand(p, &flags);
4848 /* can't set/change the rt policy */
4849 if (policy != p->policy && !rlim_rtprio)
4852 /* can't increase priority */
4853 if (param->sched_priority > p->rt_priority &&
4854 param->sched_priority > rlim_rtprio)
4858 * Like positive nice levels, dont allow tasks to
4859 * move out of SCHED_IDLE either:
4861 if (p->policy == SCHED_IDLE && policy != SCHED_IDLE)
4864 /* can't change other user's priorities */
4865 if ((current->euid != p->euid) &&
4866 (current->euid != p->uid))
4870 #ifdef CONFIG_RT_GROUP_SCHED
4872 * Do not allow realtime tasks into groups that have no runtime
4875 if (rt_policy(policy) && task_group(p)->rt_bandwidth.rt_runtime == 0)
4879 retval = security_task_setscheduler(p, policy, param);
4883 * make sure no PI-waiters arrive (or leave) while we are
4884 * changing the priority of the task:
4886 spin_lock_irqsave(&p->pi_lock, flags);
4888 * To be able to change p->policy safely, the apropriate
4889 * runqueue lock must be held.
4891 rq = __task_rq_lock(p);
4892 /* recheck policy now with rq lock held */
4893 if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
4894 policy = oldpolicy = -1;
4895 __task_rq_unlock(rq);
4896 spin_unlock_irqrestore(&p->pi_lock, flags);
4899 update_rq_clock(rq);
4900 on_rq = p->se.on_rq;
4901 running = task_current(rq, p);
4903 deactivate_task(rq, p, 0);
4905 p->sched_class->put_prev_task(rq, p);
4908 __setscheduler(rq, p, policy, param->sched_priority);
4911 p->sched_class->set_curr_task(rq);
4913 activate_task(rq, p, 0);
4915 check_class_changed(rq, p, prev_class, oldprio, running);
4917 __task_rq_unlock(rq);
4918 spin_unlock_irqrestore(&p->pi_lock, flags);
4920 rt_mutex_adjust_pi(p);
4924 EXPORT_SYMBOL_GPL(sched_setscheduler);
4927 do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
4929 struct sched_param lparam;
4930 struct task_struct *p;
4933 if (!param || pid < 0)
4935 if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
4940 p = find_process_by_pid(pid);
4942 retval = sched_setscheduler(p, policy, &lparam);
4949 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
4950 * @pid: the pid in question.
4951 * @policy: new policy.
4952 * @param: structure containing the new RT priority.
4955 sys_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
4957 /* negative values for policy are not valid */
4961 return do_sched_setscheduler(pid, policy, param);
4965 * sys_sched_setparam - set/change the RT priority of a thread
4966 * @pid: the pid in question.
4967 * @param: structure containing the new RT priority.
4969 asmlinkage long sys_sched_setparam(pid_t pid, struct sched_param __user *param)
4971 return do_sched_setscheduler(pid, -1, param);
4975 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
4976 * @pid: the pid in question.
4978 asmlinkage long sys_sched_getscheduler(pid_t pid)
4980 struct task_struct *p;
4987 read_lock(&tasklist_lock);
4988 p = find_process_by_pid(pid);
4990 retval = security_task_getscheduler(p);
4994 read_unlock(&tasklist_lock);
4999 * sys_sched_getscheduler - get the RT priority of a thread
5000 * @pid: the pid in question.
5001 * @param: structure containing the RT priority.
5003 asmlinkage long sys_sched_getparam(pid_t pid, struct sched_param __user *param)
5005 struct sched_param lp;
5006 struct task_struct *p;
5009 if (!param || pid < 0)
5012 read_lock(&tasklist_lock);
5013 p = find_process_by_pid(pid);
5018 retval = security_task_getscheduler(p);
5022 lp.sched_priority = p->rt_priority;
5023 read_unlock(&tasklist_lock);
5026 * This one might sleep, we cannot do it with a spinlock held ...
5028 retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;
5033 read_unlock(&tasklist_lock);
5037 long sched_setaffinity(pid_t pid, const cpumask_t *in_mask)
5039 cpumask_t cpus_allowed;
5040 cpumask_t new_mask = *in_mask;
5041 struct task_struct *p;
5045 read_lock(&tasklist_lock);
5047 p = find_process_by_pid(pid);
5049 read_unlock(&tasklist_lock);
5055 * It is not safe to call set_cpus_allowed with the
5056 * tasklist_lock held. We will bump the task_struct's
5057 * usage count and then drop tasklist_lock.
5060 read_unlock(&tasklist_lock);
5063 if ((current->euid != p->euid) && (current->euid != p->uid) &&
5064 !capable(CAP_SYS_NICE))
5067 retval = security_task_setscheduler(p, 0, NULL);
5071 cpuset_cpus_allowed(p, &cpus_allowed);
5072 cpus_and(new_mask, new_mask, cpus_allowed);
5074 retval = set_cpus_allowed_ptr(p, &new_mask);
5077 cpuset_cpus_allowed(p, &cpus_allowed);
5078 if (!cpus_subset(new_mask, cpus_allowed)) {
5080 * We must have raced with a concurrent cpuset
5081 * update. Just reset the cpus_allowed to the
5082 * cpuset's cpus_allowed
5084 new_mask = cpus_allowed;
5094 static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
5095 cpumask_t *new_mask)
5097 if (len < sizeof(cpumask_t)) {
5098 memset(new_mask, 0, sizeof(cpumask_t));
5099 } else if (len > sizeof(cpumask_t)) {
5100 len = sizeof(cpumask_t);
5102 return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
5106 * sys_sched_setaffinity - set the cpu affinity of a process
5107 * @pid: pid of the process
5108 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5109 * @user_mask_ptr: user-space pointer to the new cpu mask
5111 asmlinkage long sys_sched_setaffinity(pid_t pid, unsigned int len,
5112 unsigned long __user *user_mask_ptr)
5117 retval = get_user_cpu_mask(user_mask_ptr, len, &new_mask);
5121 return sched_setaffinity(pid, &new_mask);
5125 * Represents all cpu's present in the system
5126 * In systems capable of hotplug, this map could dynamically grow
5127 * as new cpu's are detected in the system via any platform specific
5128 * method, such as ACPI for e.g.
5131 cpumask_t cpu_present_map __read_mostly;
5132 EXPORT_SYMBOL(cpu_present_map);
5135 cpumask_t cpu_online_map __read_mostly = CPU_MASK_ALL;
5136 EXPORT_SYMBOL(cpu_online_map);
5138 cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL;
5139 EXPORT_SYMBOL(cpu_possible_map);
5142 long sched_getaffinity(pid_t pid, cpumask_t *mask)
5144 struct task_struct *p;
5148 read_lock(&tasklist_lock);
5151 p = find_process_by_pid(pid);
5155 retval = security_task_getscheduler(p);
5159 cpus_and(*mask, p->cpus_allowed, cpu_online_map);
5162 read_unlock(&tasklist_lock);
5169 * sys_sched_getaffinity - get the cpu affinity of a process
5170 * @pid: pid of the process
5171 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5172 * @user_mask_ptr: user-space pointer to hold the current cpu mask
5174 asmlinkage long sys_sched_getaffinity(pid_t pid, unsigned int len,
5175 unsigned long __user *user_mask_ptr)
5180 if (len < sizeof(cpumask_t))
5183 ret = sched_getaffinity(pid, &mask);
5187 if (copy_to_user(user_mask_ptr, &mask, sizeof(cpumask_t)))
5190 return sizeof(cpumask_t);
5194 * sys_sched_yield - yield the current processor to other threads.
5196 * This function yields the current CPU to other tasks. If there are no
5197 * other threads running on this CPU then this function will return.
5199 asmlinkage long sys_sched_yield(void)
5201 struct rq *rq = this_rq_lock();
5203 schedstat_inc(rq, yld_count);
5204 current->sched_class->yield_task(rq);
5207 * Since we are going to call schedule() anyway, there's
5208 * no need to preempt or enable interrupts:
5210 __release(rq->lock);
5211 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
5212 _raw_spin_unlock(&rq->lock);
5213 preempt_enable_no_resched();
5220 static void __cond_resched(void)
5222 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
5223 __might_sleep(__FILE__, __LINE__);
5226 * The BKS might be reacquired before we have dropped
5227 * PREEMPT_ACTIVE, which could trigger a second
5228 * cond_resched() call.
5231 add_preempt_count(PREEMPT_ACTIVE);
5233 sub_preempt_count(PREEMPT_ACTIVE);
5234 } while (need_resched());
5237 int __sched _cond_resched(void)
5239 if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE) &&
5240 system_state == SYSTEM_RUNNING) {
5246 EXPORT_SYMBOL(_cond_resched);
5249 * cond_resched_lock() - if a reschedule is pending, drop the given lock,
5250 * call schedule, and on return reacquire the lock.
5252 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
5253 * operations here to prevent schedule() from being called twice (once via
5254 * spin_unlock(), once by hand).
5256 int cond_resched_lock(spinlock_t *lock)
5258 int resched = need_resched() && system_state == SYSTEM_RUNNING;
5261 if (spin_needbreak(lock) || resched) {
5263 if (resched && need_resched())
5272 EXPORT_SYMBOL(cond_resched_lock);
5274 int __sched cond_resched_softirq(void)
5276 BUG_ON(!in_softirq());
5278 if (need_resched() && system_state == SYSTEM_RUNNING) {
5286 EXPORT_SYMBOL(cond_resched_softirq);
5289 * yield - yield the current processor to other threads.
5291 * This is a shortcut for kernel-space yielding - it marks the
5292 * thread runnable and calls sys_sched_yield().
5294 void __sched yield(void)
5296 set_current_state(TASK_RUNNING);
5299 EXPORT_SYMBOL(yield);
5302 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
5303 * that process accounting knows that this is a task in IO wait state.
5305 * But don't do that if it is a deliberate, throttling IO wait (this task
5306 * has set its backing_dev_info: the queue against which it should throttle)
5308 void __sched io_schedule(void)
5310 struct rq *rq = &__raw_get_cpu_var(runqueues);
5312 delayacct_blkio_start();
5313 atomic_inc(&rq->nr_iowait);
5315 atomic_dec(&rq->nr_iowait);
5316 delayacct_blkio_end();
5318 EXPORT_SYMBOL(io_schedule);
5320 long __sched io_schedule_timeout(long timeout)
5322 struct rq *rq = &__raw_get_cpu_var(runqueues);
5325 delayacct_blkio_start();
5326 atomic_inc(&rq->nr_iowait);
5327 ret = schedule_timeout(timeout);
5328 atomic_dec(&rq->nr_iowait);
5329 delayacct_blkio_end();
5334 * sys_sched_get_priority_max - return maximum RT priority.
5335 * @policy: scheduling class.
5337 * this syscall returns the maximum rt_priority that can be used
5338 * by a given scheduling class.
5340 asmlinkage long sys_sched_get_priority_max(int policy)
5347 ret = MAX_USER_RT_PRIO-1;
5359 * sys_sched_get_priority_min - return minimum RT priority.
5360 * @policy: scheduling class.
5362 * this syscall returns the minimum rt_priority that can be used
5363 * by a given scheduling class.
5365 asmlinkage long sys_sched_get_priority_min(int policy)
5383 * sys_sched_rr_get_interval - return the default timeslice of a process.
5384 * @pid: pid of the process.
5385 * @interval: userspace pointer to the timeslice value.
5387 * this syscall writes the default timeslice value of a given process
5388 * into the user-space timespec buffer. A value of '0' means infinity.
5391 long sys_sched_rr_get_interval(pid_t pid, struct timespec __user *interval)
5393 struct task_struct *p;
5394 unsigned int time_slice;
5402 read_lock(&tasklist_lock);
5403 p = find_process_by_pid(pid);
5407 retval = security_task_getscheduler(p);
5412 * Time slice is 0 for SCHED_FIFO tasks and for SCHED_OTHER
5413 * tasks that are on an otherwise idle runqueue:
5416 if (p->policy == SCHED_RR) {
5417 time_slice = DEF_TIMESLICE;
5418 } else if (p->policy != SCHED_FIFO) {
5419 struct sched_entity *se = &p->se;
5420 unsigned long flags;
5423 rq = task_rq_lock(p, &flags);
5424 if (rq->cfs.load.weight)
5425 time_slice = NS_TO_JIFFIES(sched_slice(&rq->cfs, se));
5426 task_rq_unlock(rq, &flags);
5428 read_unlock(&tasklist_lock);
5429 jiffies_to_timespec(time_slice, &t);
5430 retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;
5434 read_unlock(&tasklist_lock);
5438 static const char stat_nam[] = TASK_STATE_TO_CHAR_STR;
5440 void sched_show_task(struct task_struct *p)
5442 unsigned long free = 0;
5445 state = p->state ? __ffs(p->state) + 1 : 0;
5446 printk(KERN_INFO "%-13.13s %c", p->comm,
5447 state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?');
5448 #if BITS_PER_LONG == 32
5449 if (state == TASK_RUNNING)
5450 printk(KERN_CONT " running ");
5452 printk(KERN_CONT " %08lx ", thread_saved_pc(p));
5454 if (state == TASK_RUNNING)
5455 printk(KERN_CONT " running task ");
5457 printk(KERN_CONT " %016lx ", thread_saved_pc(p));
5459 #ifdef CONFIG_DEBUG_STACK_USAGE
5461 unsigned long *n = end_of_stack(p);
5464 free = (unsigned long)n - (unsigned long)end_of_stack(p);
5467 printk(KERN_CONT "%5lu %5d %6d\n", free,
5468 task_pid_nr(p), task_pid_nr(p->real_parent));
5470 show_stack(p, NULL);
5473 void show_state_filter(unsigned long state_filter)
5475 struct task_struct *g, *p;
5477 #if BITS_PER_LONG == 32
5479 " task PC stack pid father\n");
5482 " task PC stack pid father\n");
5484 read_lock(&tasklist_lock);
5485 do_each_thread(g, p) {
5487 * reset the NMI-timeout, listing all files on a slow
5488 * console might take alot of time:
5490 touch_nmi_watchdog();
5491 if (!state_filter || (p->state & state_filter))
5493 } while_each_thread(g, p);
5495 touch_all_softlockup_watchdogs();
5497 #ifdef CONFIG_SCHED_DEBUG
5498 sysrq_sched_debug_show();
5500 read_unlock(&tasklist_lock);
5502 * Only show locks if all tasks are dumped:
5504 if (state_filter == -1)
5505 debug_show_all_locks();
5508 void __cpuinit init_idle_bootup_task(struct task_struct *idle)
5510 idle->sched_class = &idle_sched_class;
5514 * init_idle - set up an idle thread for a given CPU
5515 * @idle: task in question
5516 * @cpu: cpu the idle task belongs to
5518 * NOTE: this function does not set the idle thread's NEED_RESCHED
5519 * flag, to make booting more robust.
5521 void __cpuinit init_idle(struct task_struct *idle, int cpu)
5523 struct rq *rq = cpu_rq(cpu);
5524 unsigned long flags;
5527 idle->se.exec_start = sched_clock();
5529 idle->prio = idle->normal_prio = MAX_PRIO;
5530 idle->cpus_allowed = cpumask_of_cpu(cpu);
5531 __set_task_cpu(idle, cpu);
5533 spin_lock_irqsave(&rq->lock, flags);
5534 rq->curr = rq->idle = idle;
5535 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
5538 spin_unlock_irqrestore(&rq->lock, flags);
5540 /* Set the preempt count _outside_ the spinlocks! */
5541 #if defined(CONFIG_PREEMPT)
5542 task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0);
5544 task_thread_info(idle)->preempt_count = 0;
5547 * The idle tasks have their own, simple scheduling class:
5549 idle->sched_class = &idle_sched_class;
5553 * In a system that switches off the HZ timer nohz_cpu_mask
5554 * indicates which cpus entered this state. This is used
5555 * in the rcu update to wait only for active cpus. For system
5556 * which do not switch off the HZ timer nohz_cpu_mask should
5557 * always be CPU_MASK_NONE.
5559 cpumask_t nohz_cpu_mask = CPU_MASK_NONE;
5562 * Increase the granularity value when there are more CPUs,
5563 * because with more CPUs the 'effective latency' as visible
5564 * to users decreases. But the relationship is not linear,
5565 * so pick a second-best guess by going with the log2 of the
5568 * This idea comes from the SD scheduler of Con Kolivas:
5570 static inline void sched_init_granularity(void)
5572 unsigned int factor = 1 + ilog2(num_online_cpus());
5573 const unsigned long limit = 200000000;
5575 sysctl_sched_min_granularity *= factor;
5576 if (sysctl_sched_min_granularity > limit)
5577 sysctl_sched_min_granularity = limit;
5579 sysctl_sched_latency *= factor;
5580 if (sysctl_sched_latency > limit)
5581 sysctl_sched_latency = limit;
5583 sysctl_sched_wakeup_granularity *= factor;
5588 * This is how migration works:
5590 * 1) we queue a struct migration_req structure in the source CPU's
5591 * runqueue and wake up that CPU's migration thread.
5592 * 2) we down() the locked semaphore => thread blocks.
5593 * 3) migration thread wakes up (implicitly it forces the migrated
5594 * thread off the CPU)
5595 * 4) it gets the migration request and checks whether the migrated
5596 * task is still in the wrong runqueue.
5597 * 5) if it's in the wrong runqueue then the migration thread removes
5598 * it and puts it into the right queue.
5599 * 6) migration thread up()s the semaphore.
5600 * 7) we wake up and the migration is done.
5604 * Change a given task's CPU affinity. Migrate the thread to a
5605 * proper CPU and schedule it away if the CPU it's executing on
5606 * is removed from the allowed bitmask.
5608 * NOTE: the caller must have a valid reference to the task, the
5609 * task must not exit() & deallocate itself prematurely. The
5610 * call is not atomic; no spinlocks may be held.
5612 int set_cpus_allowed_ptr(struct task_struct *p, const cpumask_t *new_mask)
5614 struct migration_req req;
5615 unsigned long flags;
5619 rq = task_rq_lock(p, &flags);
5620 if (!cpus_intersects(*new_mask, cpu_online_map)) {
5625 if (p->sched_class->set_cpus_allowed)
5626 p->sched_class->set_cpus_allowed(p, new_mask);
5628 p->cpus_allowed = *new_mask;
5629 p->rt.nr_cpus_allowed = cpus_weight(*new_mask);
5632 /* Can the task run on the task's current CPU? If so, we're done */
5633 if (cpu_isset(task_cpu(p), *new_mask))
5636 if (migrate_task(p, any_online_cpu(*new_mask), &req)) {
5637 /* Need help from migration thread: drop lock and wait. */
5638 task_rq_unlock(rq, &flags);
5639 wake_up_process(rq->migration_thread);
5640 wait_for_completion(&req.done);
5641 tlb_migrate_finish(p->mm);
5645 task_rq_unlock(rq, &flags);
5649 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
5652 * Move (not current) task off this cpu, onto dest cpu. We're doing
5653 * this because either it can't run here any more (set_cpus_allowed()
5654 * away from this CPU, or CPU going down), or because we're
5655 * attempting to rebalance this task on exec (sched_exec).
5657 * So we race with normal scheduler movements, but that's OK, as long
5658 * as the task is no longer on this CPU.
5660 * Returns non-zero if task was successfully migrated.
5662 static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
5664 struct rq *rq_dest, *rq_src;
5667 if (unlikely(cpu_is_offline(dest_cpu)))
5670 rq_src = cpu_rq(src_cpu);
5671 rq_dest = cpu_rq(dest_cpu);
5673 double_rq_lock(rq_src, rq_dest);
5674 /* Already moved. */
5675 if (task_cpu(p) != src_cpu)
5677 /* Affinity changed (again). */
5678 if (!cpu_isset(dest_cpu, p->cpus_allowed))
5681 on_rq = p->se.on_rq;
5683 deactivate_task(rq_src, p, 0);
5685 set_task_cpu(p, dest_cpu);
5687 activate_task(rq_dest, p, 0);
5688 check_preempt_curr(rq_dest, p);
5692 double_rq_unlock(rq_src, rq_dest);
5697 * migration_thread - this is a highprio system thread that performs
5698 * thread migration by bumping thread off CPU then 'pushing' onto
5701 static int migration_thread(void *data)
5703 int cpu = (long)data;
5707 BUG_ON(rq->migration_thread != current);
5709 set_current_state(TASK_INTERRUPTIBLE);
5710 while (!kthread_should_stop()) {
5711 struct migration_req *req;
5712 struct list_head *head;
5714 spin_lock_irq(&rq->lock);
5716 if (cpu_is_offline(cpu)) {
5717 spin_unlock_irq(&rq->lock);
5721 if (rq->active_balance) {
5722 active_load_balance(rq, cpu);
5723 rq->active_balance = 0;
5726 head = &rq->migration_queue;
5728 if (list_empty(head)) {
5729 spin_unlock_irq(&rq->lock);
5731 set_current_state(TASK_INTERRUPTIBLE);
5734 req = list_entry(head->next, struct migration_req, list);
5735 list_del_init(head->next);
5737 spin_unlock(&rq->lock);
5738 __migrate_task(req->task, cpu, req->dest_cpu);
5741 complete(&req->done);
5743 __set_current_state(TASK_RUNNING);
5747 /* Wait for kthread_stop */
5748 set_current_state(TASK_INTERRUPTIBLE);
5749 while (!kthread_should_stop()) {
5751 set_current_state(TASK_INTERRUPTIBLE);
5753 __set_current_state(TASK_RUNNING);
5757 #ifdef CONFIG_HOTPLUG_CPU
5759 static int __migrate_task_irq(struct task_struct *p, int src_cpu, int dest_cpu)
5763 local_irq_disable();
5764 ret = __migrate_task(p, src_cpu, dest_cpu);
5770 * Figure out where task on dead CPU should go, use force if necessary.
5771 * NOTE: interrupts should be disabled by the caller
5773 static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p)
5775 unsigned long flags;
5782 mask = node_to_cpumask(cpu_to_node(dead_cpu));
5783 cpus_and(mask, mask, p->cpus_allowed);
5784 dest_cpu = any_online_cpu(mask);
5786 /* On any allowed CPU? */
5787 if (dest_cpu >= nr_cpu_ids)
5788 dest_cpu = any_online_cpu(p->cpus_allowed);
5790 /* No more Mr. Nice Guy. */
5791 if (dest_cpu >= nr_cpu_ids) {
5792 cpumask_t cpus_allowed;
5794 cpuset_cpus_allowed_locked(p, &cpus_allowed);
5796 * Try to stay on the same cpuset, where the
5797 * current cpuset may be a subset of all cpus.
5798 * The cpuset_cpus_allowed_locked() variant of
5799 * cpuset_cpus_allowed() will not block. It must be
5800 * called within calls to cpuset_lock/cpuset_unlock.
5802 rq = task_rq_lock(p, &flags);
5803 p->cpus_allowed = cpus_allowed;
5804 dest_cpu = any_online_cpu(p->cpus_allowed);
5805 task_rq_unlock(rq, &flags);
5808 * Don't tell them about moving exiting tasks or
5809 * kernel threads (both mm NULL), since they never
5812 if (p->mm && printk_ratelimit()) {
5813 printk(KERN_INFO "process %d (%s) no "
5814 "longer affine to cpu%d\n",
5815 task_pid_nr(p), p->comm, dead_cpu);
5818 } while (!__migrate_task_irq(p, dead_cpu, dest_cpu));
5822 * While a dead CPU has no uninterruptible tasks queued at this point,
5823 * it might still have a nonzero ->nr_uninterruptible counter, because
5824 * for performance reasons the counter is not stricly tracking tasks to
5825 * their home CPUs. So we just add the counter to another CPU's counter,
5826 * to keep the global sum constant after CPU-down:
5828 static void migrate_nr_uninterruptible(struct rq *rq_src)
5830 struct rq *rq_dest = cpu_rq(any_online_cpu(*CPU_MASK_ALL_PTR));
5831 unsigned long flags;
5833 local_irq_save(flags);
5834 double_rq_lock(rq_src, rq_dest);
5835 rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible;
5836 rq_src->nr_uninterruptible = 0;
5837 double_rq_unlock(rq_src, rq_dest);
5838 local_irq_restore(flags);
5841 /* Run through task list and migrate tasks from the dead cpu. */
5842 static void migrate_live_tasks(int src_cpu)
5844 struct task_struct *p, *t;
5846 read_lock(&tasklist_lock);
5848 do_each_thread(t, p) {
5852 if (task_cpu(p) == src_cpu)
5853 move_task_off_dead_cpu(src_cpu, p);
5854 } while_each_thread(t, p);
5856 read_unlock(&tasklist_lock);
5860 * Schedules idle task to be the next runnable task on current CPU.
5861 * It does so by boosting its priority to highest possible.
5862 * Used by CPU offline code.
5864 void sched_idle_next(void)
5866 int this_cpu = smp_processor_id();
5867 struct rq *rq = cpu_rq(this_cpu);
5868 struct task_struct *p = rq->idle;
5869 unsigned long flags;
5871 /* cpu has to be offline */
5872 BUG_ON(cpu_online(this_cpu));
5875 * Strictly not necessary since rest of the CPUs are stopped by now
5876 * and interrupts disabled on the current cpu.
5878 spin_lock_irqsave(&rq->lock, flags);
5880 __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
5882 update_rq_clock(rq);
5883 activate_task(rq, p, 0);
5885 spin_unlock_irqrestore(&rq->lock, flags);
5889 * Ensures that the idle task is using init_mm right before its cpu goes
5892 void idle_task_exit(void)
5894 struct mm_struct *mm = current->active_mm;
5896 BUG_ON(cpu_online(smp_processor_id()));
5899 switch_mm(mm, &init_mm, current);
5903 /* called under rq->lock with disabled interrupts */
5904 static void migrate_dead(unsigned int dead_cpu, struct task_struct *p)
5906 struct rq *rq = cpu_rq(dead_cpu);
5908 /* Must be exiting, otherwise would be on tasklist. */
5909 BUG_ON(!p->exit_state);
5911 /* Cannot have done final schedule yet: would have vanished. */
5912 BUG_ON(p->state == TASK_DEAD);
5917 * Drop lock around migration; if someone else moves it,
5918 * that's OK. No task can be added to this CPU, so iteration is
5921 spin_unlock_irq(&rq->lock);
5922 move_task_off_dead_cpu(dead_cpu, p);
5923 spin_lock_irq(&rq->lock);
5928 /* release_task() removes task from tasklist, so we won't find dead tasks. */
5929 static void migrate_dead_tasks(unsigned int dead_cpu)
5931 struct rq *rq = cpu_rq(dead_cpu);
5932 struct task_struct *next;
5935 if (!rq->nr_running)
5937 update_rq_clock(rq);
5938 next = pick_next_task(rq, rq->curr);
5941 next->sched_class->put_prev_task(rq, next);
5942 migrate_dead(dead_cpu, next);
5946 #endif /* CONFIG_HOTPLUG_CPU */
5948 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
5950 static struct ctl_table sd_ctl_dir[] = {
5952 .procname = "sched_domain",
5958 static struct ctl_table sd_ctl_root[] = {
5960 .ctl_name = CTL_KERN,
5961 .procname = "kernel",
5963 .child = sd_ctl_dir,
5968 static struct ctl_table *sd_alloc_ctl_entry(int n)
5970 struct ctl_table *entry =
5971 kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL);
5976 static void sd_free_ctl_entry(struct ctl_table **tablep)
5978 struct ctl_table *entry;
5981 * In the intermediate directories, both the child directory and
5982 * procname are dynamically allocated and could fail but the mode
5983 * will always be set. In the lowest directory the names are
5984 * static strings and all have proc handlers.
5986 for (entry = *tablep; entry->mode; entry++) {
5988 sd_free_ctl_entry(&entry->child);
5989 if (entry->proc_handler == NULL)
5990 kfree(entry->procname);
5998 set_table_entry(struct ctl_table *entry,
5999 const char *procname, void *data, int maxlen,
6000 mode_t mode, proc_handler *proc_handler)
6002 entry->procname = procname;
6004 entry->maxlen = maxlen;
6006 entry->proc_handler = proc_handler;
6009 static struct ctl_table *
6010 sd_alloc_ctl_domain_table(struct sched_domain *sd)
6012 struct ctl_table *table = sd_alloc_ctl_entry(12);
6017 set_table_entry(&table[0], "min_interval", &sd->min_interval,
6018 sizeof(long), 0644, proc_doulongvec_minmax);
6019 set_table_entry(&table[1], "max_interval", &sd->max_interval,
6020 sizeof(long), 0644, proc_doulongvec_minmax);
6021 set_table_entry(&table[2], "busy_idx", &sd->busy_idx,
6022 sizeof(int), 0644, proc_dointvec_minmax);
6023 set_table_entry(&table[3], "idle_idx", &sd->idle_idx,
6024 sizeof(int), 0644, proc_dointvec_minmax);
6025 set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx,
6026 sizeof(int), 0644, proc_dointvec_minmax);
6027 set_table_entry(&table[5], "wake_idx", &sd->wake_idx,
6028 sizeof(int), 0644, proc_dointvec_minmax);
6029 set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx,
6030 sizeof(int), 0644, proc_dointvec_minmax);
6031 set_table_entry(&table[7], "busy_factor", &sd->busy_factor,
6032 sizeof(int), 0644, proc_dointvec_minmax);
6033 set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct,
6034 sizeof(int), 0644, proc_dointvec_minmax);
6035 set_table_entry(&table[9], "cache_nice_tries",
6036 &sd->cache_nice_tries,
6037 sizeof(int), 0644, proc_dointvec_minmax);
6038 set_table_entry(&table[10], "flags", &sd->flags,
6039 sizeof(int), 0644, proc_dointvec_minmax);
6040 /* &table[11] is terminator */
6045 static ctl_table *sd_alloc_ctl_cpu_table(int cpu)
6047 struct ctl_table *entry, *table;
6048 struct sched_domain *sd;
6049 int domain_num = 0, i;
6052 for_each_domain(cpu, sd)
6054 entry = table = sd_alloc_ctl_entry(domain_num + 1);
6059 for_each_domain(cpu, sd) {
6060 snprintf(buf, 32, "domain%d", i);
6061 entry->procname = kstrdup(buf, GFP_KERNEL);
6063 entry->child = sd_alloc_ctl_domain_table(sd);
6070 static struct ctl_table_header *sd_sysctl_header;
6071 static void register_sched_domain_sysctl(void)
6073 int i, cpu_num = num_online_cpus();
6074 struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1);
6077 WARN_ON(sd_ctl_dir[0].child);
6078 sd_ctl_dir[0].child = entry;
6083 for_each_online_cpu(i) {
6084 snprintf(buf, 32, "cpu%d", i);
6085 entry->procname = kstrdup(buf, GFP_KERNEL);
6087 entry->child = sd_alloc_ctl_cpu_table(i);
6091 WARN_ON(sd_sysctl_header);
6092 sd_sysctl_header = register_sysctl_table(sd_ctl_root);
6095 /* may be called multiple times per register */
6096 static void unregister_sched_domain_sysctl(void)
6098 if (sd_sysctl_header)
6099 unregister_sysctl_table(sd_sysctl_header);
6100 sd_sysctl_header = NULL;
6101 if (sd_ctl_dir[0].child)
6102 sd_free_ctl_entry(&sd_ctl_dir[0].child);
6105 static void register_sched_domain_sysctl(void)
6108 static void unregister_sched_domain_sysctl(void)
6114 * migration_call - callback that gets triggered when a CPU is added.
6115 * Here we can start up the necessary migration thread for the new CPU.
6117 static int __cpuinit
6118 migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
6120 struct task_struct *p;
6121 int cpu = (long)hcpu;
6122 unsigned long flags;
6127 case CPU_UP_PREPARE:
6128 case CPU_UP_PREPARE_FROZEN:
6129 p = kthread_create(migration_thread, hcpu, "migration/%d", cpu);
6132 kthread_bind(p, cpu);
6133 /* Must be high prio: stop_machine expects to yield to it. */
6134 rq = task_rq_lock(p, &flags);
6135 __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
6136 task_rq_unlock(rq, &flags);
6137 cpu_rq(cpu)->migration_thread = p;
6141 case CPU_ONLINE_FROZEN:
6142 /* Strictly unnecessary, as first user will wake it. */
6143 wake_up_process(cpu_rq(cpu)->migration_thread);
6145 /* Update our root-domain */
6147 spin_lock_irqsave(&rq->lock, flags);
6149 BUG_ON(!cpu_isset(cpu, rq->rd->span));
6150 cpu_set(cpu, rq->rd->online);
6152 spin_unlock_irqrestore(&rq->lock, flags);
6155 #ifdef CONFIG_HOTPLUG_CPU
6156 case CPU_UP_CANCELED:
6157 case CPU_UP_CANCELED_FROZEN:
6158 if (!cpu_rq(cpu)->migration_thread)
6160 /* Unbind it from offline cpu so it can run. Fall thru. */
6161 kthread_bind(cpu_rq(cpu)->migration_thread,
6162 any_online_cpu(cpu_online_map));
6163 kthread_stop(cpu_rq(cpu)->migration_thread);
6164 cpu_rq(cpu)->migration_thread = NULL;
6168 case CPU_DEAD_FROZEN:
6169 cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */
6170 migrate_live_tasks(cpu);
6172 kthread_stop(rq->migration_thread);
6173 rq->migration_thread = NULL;
6174 /* Idle task back to normal (off runqueue, low prio) */
6175 spin_lock_irq(&rq->lock);
6176 update_rq_clock(rq);
6177 deactivate_task(rq, rq->idle, 0);
6178 rq->idle->static_prio = MAX_PRIO;
6179 __setscheduler(rq, rq->idle, SCHED_NORMAL, 0);
6180 rq->idle->sched_class = &idle_sched_class;
6181 migrate_dead_tasks(cpu);
6182 spin_unlock_irq(&rq->lock);
6184 migrate_nr_uninterruptible(rq);
6185 BUG_ON(rq->nr_running != 0);
6188 * No need to migrate the tasks: it was best-effort if
6189 * they didn't take sched_hotcpu_mutex. Just wake up
6192 spin_lock_irq(&rq->lock);
6193 while (!list_empty(&rq->migration_queue)) {
6194 struct migration_req *req;
6196 req = list_entry(rq->migration_queue.next,
6197 struct migration_req, list);
6198 list_del_init(&req->list);
6199 complete(&req->done);
6201 spin_unlock_irq(&rq->lock);
6205 case CPU_DYING_FROZEN:
6206 /* Update our root-domain */
6208 spin_lock_irqsave(&rq->lock, flags);
6210 BUG_ON(!cpu_isset(cpu, rq->rd->span));
6211 cpu_clear(cpu, rq->rd->online);
6213 spin_unlock_irqrestore(&rq->lock, flags);
6220 /* Register at highest priority so that task migration (migrate_all_tasks)
6221 * happens before everything else.
6223 static struct notifier_block __cpuinitdata migration_notifier = {
6224 .notifier_call = migration_call,
6228 void __init migration_init(void)
6230 void *cpu = (void *)(long)smp_processor_id();
6233 /* Start one for the boot CPU: */
6234 err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
6235 BUG_ON(err == NOTIFY_BAD);
6236 migration_call(&migration_notifier, CPU_ONLINE, cpu);
6237 register_cpu_notifier(&migration_notifier);
6243 #ifdef CONFIG_SCHED_DEBUG
6245 static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
6246 cpumask_t *groupmask)
6248 struct sched_group *group = sd->groups;
6251 cpulist_scnprintf(str, sizeof(str), sd->span);
6252 cpus_clear(*groupmask);
6254 printk(KERN_DEBUG "%*s domain %d: ", level, "", level);
6256 if (!(sd->flags & SD_LOAD_BALANCE)) {
6257 printk("does not load-balance\n");
6259 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain"
6264 printk(KERN_CONT "span %s\n", str);
6266 if (!cpu_isset(cpu, sd->span)) {
6267 printk(KERN_ERR "ERROR: domain->span does not contain "
6270 if (!cpu_isset(cpu, group->cpumask)) {
6271 printk(KERN_ERR "ERROR: domain->groups does not contain"
6275 printk(KERN_DEBUG "%*s groups:", level + 1, "");
6279 printk(KERN_ERR "ERROR: group is NULL\n");
6283 if (!group->__cpu_power) {
6284 printk(KERN_CONT "\n");
6285 printk(KERN_ERR "ERROR: domain->cpu_power not "
6290 if (!cpus_weight(group->cpumask)) {
6291 printk(KERN_CONT "\n");
6292 printk(KERN_ERR "ERROR: empty group\n");
6296 if (cpus_intersects(*groupmask, group->cpumask)) {
6297 printk(KERN_CONT "\n");
6298 printk(KERN_ERR "ERROR: repeated CPUs\n");
6302 cpus_or(*groupmask, *groupmask, group->cpumask);
6304 cpulist_scnprintf(str, sizeof(str), group->cpumask);
6305 printk(KERN_CONT " %s", str);
6307 group = group->next;
6308 } while (group != sd->groups);
6309 printk(KERN_CONT "\n");
6311 if (!cpus_equal(sd->span, *groupmask))
6312 printk(KERN_ERR "ERROR: groups don't span domain->span\n");
6314 if (sd->parent && !cpus_subset(*groupmask, sd->parent->span))
6315 printk(KERN_ERR "ERROR: parent span is not a superset "
6316 "of domain->span\n");
6320 static void sched_domain_debug(struct sched_domain *sd, int cpu)
6322 cpumask_t *groupmask;
6326 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
6330 printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu);
6332 groupmask = kmalloc(sizeof(cpumask_t), GFP_KERNEL);
6334 printk(KERN_DEBUG "Cannot load-balance (out of memory)\n");
6339 if (sched_domain_debug_one(sd, cpu, level, groupmask))
6349 # define sched_domain_debug(sd, cpu) do { } while (0)
6352 static int sd_degenerate(struct sched_domain *sd)
6354 if (cpus_weight(sd->span) == 1)
6357 /* Following flags need at least 2 groups */
6358 if (sd->flags & (SD_LOAD_BALANCE |
6359 SD_BALANCE_NEWIDLE |
6363 SD_SHARE_PKG_RESOURCES)) {
6364 if (sd->groups != sd->groups->next)
6368 /* Following flags don't use groups */
6369 if (sd->flags & (SD_WAKE_IDLE |
6378 sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
6380 unsigned long cflags = sd->flags, pflags = parent->flags;
6382 if (sd_degenerate(parent))
6385 if (!cpus_equal(sd->span, parent->span))
6388 /* Does parent contain flags not in child? */
6389 /* WAKE_BALANCE is a subset of WAKE_AFFINE */
6390 if (cflags & SD_WAKE_AFFINE)
6391 pflags &= ~SD_WAKE_BALANCE;
6392 /* Flags needing groups don't count if only 1 group in parent */
6393 if (parent->groups == parent->groups->next) {
6394 pflags &= ~(SD_LOAD_BALANCE |
6395 SD_BALANCE_NEWIDLE |
6399 SD_SHARE_PKG_RESOURCES);
6401 if (~cflags & pflags)
6407 static void rq_attach_root(struct rq *rq, struct root_domain *rd)
6409 unsigned long flags;
6410 const struct sched_class *class;
6412 spin_lock_irqsave(&rq->lock, flags);
6415 struct root_domain *old_rd = rq->rd;
6417 for (class = sched_class_highest; class; class = class->next) {
6418 if (class->leave_domain)
6419 class->leave_domain(rq);
6422 cpu_clear(rq->cpu, old_rd->span);
6423 cpu_clear(rq->cpu, old_rd->online);
6425 if (atomic_dec_and_test(&old_rd->refcount))
6429 atomic_inc(&rd->refcount);
6432 cpu_set(rq->cpu, rd->span);
6433 if (cpu_isset(rq->cpu, cpu_online_map))
6434 cpu_set(rq->cpu, rd->online);
6436 for (class = sched_class_highest; class; class = class->next) {
6437 if (class->join_domain)
6438 class->join_domain(rq);
6441 spin_unlock_irqrestore(&rq->lock, flags);
6444 static void init_rootdomain(struct root_domain *rd)
6446 memset(rd, 0, sizeof(*rd));
6448 cpus_clear(rd->span);
6449 cpus_clear(rd->online);
6452 static void init_defrootdomain(void)
6454 init_rootdomain(&def_root_domain);
6455 atomic_set(&def_root_domain.refcount, 1);
6458 static struct root_domain *alloc_rootdomain(void)
6460 struct root_domain *rd;
6462 rd = kmalloc(sizeof(*rd), GFP_KERNEL);
6466 init_rootdomain(rd);
6472 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
6473 * hold the hotplug lock.
6476 cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
6478 struct rq *rq = cpu_rq(cpu);
6479 struct sched_domain *tmp;
6481 /* Remove the sched domains which do not contribute to scheduling. */
6482 for (tmp = sd; tmp; tmp = tmp->parent) {
6483 struct sched_domain *parent = tmp->parent;
6486 if (sd_parent_degenerate(tmp, parent)) {
6487 tmp->parent = parent->parent;
6489 parent->parent->child = tmp;
6493 if (sd && sd_degenerate(sd)) {
6499 sched_domain_debug(sd, cpu);
6501 rq_attach_root(rq, rd);
6502 rcu_assign_pointer(rq->sd, sd);
6505 /* cpus with isolated domains */
6506 static cpumask_t cpu_isolated_map = CPU_MASK_NONE;
6508 /* Setup the mask of cpus configured for isolated domains */
6509 static int __init isolated_cpu_setup(char *str)
6511 int ints[NR_CPUS], i;
6513 str = get_options(str, ARRAY_SIZE(ints), ints);
6514 cpus_clear(cpu_isolated_map);
6515 for (i = 1; i <= ints[0]; i++)
6516 if (ints[i] < NR_CPUS)
6517 cpu_set(ints[i], cpu_isolated_map);
6521 __setup("isolcpus=", isolated_cpu_setup);
6524 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
6525 * to a function which identifies what group(along with sched group) a CPU
6526 * belongs to. The return value of group_fn must be a >= 0 and < NR_CPUS
6527 * (due to the fact that we keep track of groups covered with a cpumask_t).
6529 * init_sched_build_groups will build a circular linked list of the groups
6530 * covered by the given span, and will set each group's ->cpumask correctly,
6531 * and ->cpu_power to 0.
6534 init_sched_build_groups(const cpumask_t *span, const cpumask_t *cpu_map,
6535 int (*group_fn)(int cpu, const cpumask_t *cpu_map,
6536 struct sched_group **sg,
6537 cpumask_t *tmpmask),
6538 cpumask_t *covered, cpumask_t *tmpmask)
6540 struct sched_group *first = NULL, *last = NULL;
6543 cpus_clear(*covered);
6545 for_each_cpu_mask(i, *span) {
6546 struct sched_group *sg;
6547 int group = group_fn(i, cpu_map, &sg, tmpmask);
6550 if (cpu_isset(i, *covered))
6553 cpus_clear(sg->cpumask);
6554 sg->__cpu_power = 0;
6556 for_each_cpu_mask(j, *span) {
6557 if (group_fn(j, cpu_map, NULL, tmpmask) != group)
6560 cpu_set(j, *covered);
6561 cpu_set(j, sg->cpumask);
6572 #define SD_NODES_PER_DOMAIN 16
6577 * find_next_best_node - find the next node to include in a sched_domain
6578 * @node: node whose sched_domain we're building
6579 * @used_nodes: nodes already in the sched_domain
6581 * Find the next node to include in a given scheduling domain. Simply
6582 * finds the closest node not already in the @used_nodes map.
6584 * Should use nodemask_t.
6586 static int find_next_best_node(int node, nodemask_t *used_nodes)
6588 int i, n, val, min_val, best_node = 0;
6592 for (i = 0; i < MAX_NUMNODES; i++) {
6593 /* Start at @node */
6594 n = (node + i) % MAX_NUMNODES;
6596 if (!nr_cpus_node(n))
6599 /* Skip already used nodes */
6600 if (node_isset(n, *used_nodes))
6603 /* Simple min distance search */
6604 val = node_distance(node, n);
6606 if (val < min_val) {
6612 node_set(best_node, *used_nodes);
6617 * sched_domain_node_span - get a cpumask for a node's sched_domain
6618 * @node: node whose cpumask we're constructing
6619 * @span: resulting cpumask
6621 * Given a node, construct a good cpumask for its sched_domain to span. It
6622 * should be one that prevents unnecessary balancing, but also spreads tasks
6625 static void sched_domain_node_span(int node, cpumask_t *span)
6627 nodemask_t used_nodes;
6628 node_to_cpumask_ptr(nodemask, node);
6632 nodes_clear(used_nodes);
6634 cpus_or(*span, *span, *nodemask);
6635 node_set(node, used_nodes);
6637 for (i = 1; i < SD_NODES_PER_DOMAIN; i++) {
6638 int next_node = find_next_best_node(node, &used_nodes);
6640 node_to_cpumask_ptr_next(nodemask, next_node);
6641 cpus_or(*span, *span, *nodemask);
6646 int sched_smt_power_savings = 0, sched_mc_power_savings = 0;
6649 * SMT sched-domains:
6651 #ifdef CONFIG_SCHED_SMT
6652 static DEFINE_PER_CPU(struct sched_domain, cpu_domains);
6653 static DEFINE_PER_CPU(struct sched_group, sched_group_cpus);
6656 cpu_to_cpu_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg,
6660 *sg = &per_cpu(sched_group_cpus, cpu);
6666 * multi-core sched-domains:
6668 #ifdef CONFIG_SCHED_MC
6669 static DEFINE_PER_CPU(struct sched_domain, core_domains);
6670 static DEFINE_PER_CPU(struct sched_group, sched_group_core);
6673 #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
6675 cpu_to_core_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg,
6680 *mask = per_cpu(cpu_sibling_map, cpu);
6681 cpus_and(*mask, *mask, *cpu_map);
6682 group = first_cpu(*mask);
6684 *sg = &per_cpu(sched_group_core, group);
6687 #elif defined(CONFIG_SCHED_MC)
6689 cpu_to_core_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg,
6693 *sg = &per_cpu(sched_group_core, cpu);
6698 static DEFINE_PER_CPU(struct sched_domain, phys_domains);
6699 static DEFINE_PER_CPU(struct sched_group, sched_group_phys);
6702 cpu_to_phys_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg,
6706 #ifdef CONFIG_SCHED_MC
6707 *mask = cpu_coregroup_map(cpu);
6708 cpus_and(*mask, *mask, *cpu_map);
6709 group = first_cpu(*mask);
6710 #elif defined(CONFIG_SCHED_SMT)
6711 *mask = per_cpu(cpu_sibling_map, cpu);
6712 cpus_and(*mask, *mask, *cpu_map);
6713 group = first_cpu(*mask);
6718 *sg = &per_cpu(sched_group_phys, group);
6724 * The init_sched_build_groups can't handle what we want to do with node
6725 * groups, so roll our own. Now each node has its own list of groups which
6726 * gets dynamically allocated.
6728 static DEFINE_PER_CPU(struct sched_domain, node_domains);
6729 static struct sched_group ***sched_group_nodes_bycpu;
6731 static DEFINE_PER_CPU(struct sched_domain, allnodes_domains);
6732 static DEFINE_PER_CPU(struct sched_group, sched_group_allnodes);
6734 static int cpu_to_allnodes_group(int cpu, const cpumask_t *cpu_map,
6735 struct sched_group **sg, cpumask_t *nodemask)
6739 *nodemask = node_to_cpumask(cpu_to_node(cpu));
6740 cpus_and(*nodemask, *nodemask, *cpu_map);
6741 group = first_cpu(*nodemask);
6744 *sg = &per_cpu(sched_group_allnodes, group);
6748 static void init_numa_sched_groups_power(struct sched_group *group_head)
6750 struct sched_group *sg = group_head;
6756 for_each_cpu_mask(j, sg->cpumask) {
6757 struct sched_domain *sd;
6759 sd = &per_cpu(phys_domains, j);
6760 if (j != first_cpu(sd->groups->cpumask)) {
6762 * Only add "power" once for each
6768 sg_inc_cpu_power(sg, sd->groups->__cpu_power);
6771 } while (sg != group_head);
6776 /* Free memory allocated for various sched_group structures */
6777 static void free_sched_groups(const cpumask_t *cpu_map, cpumask_t *nodemask)
6781 for_each_cpu_mask(cpu, *cpu_map) {
6782 struct sched_group **sched_group_nodes
6783 = sched_group_nodes_bycpu[cpu];
6785 if (!sched_group_nodes)
6788 for (i = 0; i < MAX_NUMNODES; i++) {
6789 struct sched_group *oldsg, *sg = sched_group_nodes[i];
6791 *nodemask = node_to_cpumask(i);
6792 cpus_and(*nodemask, *nodemask, *cpu_map);
6793 if (cpus_empty(*nodemask))
6803 if (oldsg != sched_group_nodes[i])
6806 kfree(sched_group_nodes);
6807 sched_group_nodes_bycpu[cpu] = NULL;
6811 static void free_sched_groups(const cpumask_t *cpu_map, cpumask_t *nodemask)
6817 * Initialize sched groups cpu_power.
6819 * cpu_power indicates the capacity of sched group, which is used while
6820 * distributing the load between different sched groups in a sched domain.
6821 * Typically cpu_power for all the groups in a sched domain will be same unless
6822 * there are asymmetries in the topology. If there are asymmetries, group
6823 * having more cpu_power will pickup more load compared to the group having
6826 * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents
6827 * the maximum number of tasks a group can handle in the presence of other idle
6828 * or lightly loaded groups in the same sched domain.
6830 static void init_sched_groups_power(int cpu, struct sched_domain *sd)
6832 struct sched_domain *child;
6833 struct sched_group *group;
6835 WARN_ON(!sd || !sd->groups);
6837 if (cpu != first_cpu(sd->groups->cpumask))
6842 sd->groups->__cpu_power = 0;
6845 * For perf policy, if the groups in child domain share resources
6846 * (for example cores sharing some portions of the cache hierarchy
6847 * or SMT), then set this domain groups cpu_power such that each group
6848 * can handle only one task, when there are other idle groups in the
6849 * same sched domain.
6851 if (!child || (!(sd->flags & SD_POWERSAVINGS_BALANCE) &&
6853 (SD_SHARE_CPUPOWER | SD_SHARE_PKG_RESOURCES)))) {
6854 sg_inc_cpu_power(sd->groups, SCHED_LOAD_SCALE);
6859 * add cpu_power of each child group to this groups cpu_power
6861 group = child->groups;
6863 sg_inc_cpu_power(sd->groups, group->__cpu_power);
6864 group = group->next;
6865 } while (group != child->groups);
6869 * Initializers for schedule domains
6870 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
6873 #define SD_INIT(sd, type) sd_init_##type(sd)
6874 #define SD_INIT_FUNC(type) \
6875 static noinline void sd_init_##type(struct sched_domain *sd) \
6877 memset(sd, 0, sizeof(*sd)); \
6878 *sd = SD_##type##_INIT; \
6879 sd->level = SD_LV_##type; \
6884 SD_INIT_FUNC(ALLNODES)
6887 #ifdef CONFIG_SCHED_SMT
6888 SD_INIT_FUNC(SIBLING)
6890 #ifdef CONFIG_SCHED_MC
6895 * To minimize stack usage kmalloc room for cpumasks and share the
6896 * space as the usage in build_sched_domains() dictates. Used only
6897 * if the amount of space is significant.
6900 cpumask_t tmpmask; /* make this one first */
6903 cpumask_t this_sibling_map;
6904 cpumask_t this_core_map;
6906 cpumask_t send_covered;
6909 cpumask_t domainspan;
6911 cpumask_t notcovered;
6916 #define SCHED_CPUMASK_ALLOC 1
6917 #define SCHED_CPUMASK_FREE(v) kfree(v)
6918 #define SCHED_CPUMASK_DECLARE(v) struct allmasks *v
6920 #define SCHED_CPUMASK_ALLOC 0
6921 #define SCHED_CPUMASK_FREE(v)
6922 #define SCHED_CPUMASK_DECLARE(v) struct allmasks _v, *v = &_v
6925 #define SCHED_CPUMASK_VAR(v, a) cpumask_t *v = (cpumask_t *) \
6926 ((unsigned long)(a) + offsetof(struct allmasks, v))
6928 static int default_relax_domain_level = -1;
6930 static int __init setup_relax_domain_level(char *str)
6934 val = simple_strtoul(str, NULL, 0);
6935 if (val < SD_LV_MAX)
6936 default_relax_domain_level = val;
6940 __setup("relax_domain_level=", setup_relax_domain_level);
6942 static void set_domain_attribute(struct sched_domain *sd,
6943 struct sched_domain_attr *attr)
6947 if (!attr || attr->relax_domain_level < 0) {
6948 if (default_relax_domain_level < 0)
6951 request = default_relax_domain_level;
6953 request = attr->relax_domain_level;
6954 if (request < sd->level) {
6955 /* turn off idle balance on this domain */
6956 sd->flags &= ~(SD_WAKE_IDLE|SD_BALANCE_NEWIDLE);
6958 /* turn on idle balance on this domain */
6959 sd->flags |= (SD_WAKE_IDLE_FAR|SD_BALANCE_NEWIDLE);
6964 * Build sched domains for a given set of cpus and attach the sched domains
6965 * to the individual cpus
6967 static int __build_sched_domains(const cpumask_t *cpu_map,
6968 struct sched_domain_attr *attr)
6971 struct root_domain *rd;
6972 SCHED_CPUMASK_DECLARE(allmasks);
6975 struct sched_group **sched_group_nodes = NULL;
6976 int sd_allnodes = 0;
6979 * Allocate the per-node list of sched groups
6981 sched_group_nodes = kcalloc(MAX_NUMNODES, sizeof(struct sched_group *),
6983 if (!sched_group_nodes) {
6984 printk(KERN_WARNING "Can not alloc sched group node list\n");
6989 rd = alloc_rootdomain();
6991 printk(KERN_WARNING "Cannot alloc root domain\n");
6993 kfree(sched_group_nodes);
6998 #if SCHED_CPUMASK_ALLOC
6999 /* get space for all scratch cpumask variables */
7000 allmasks = kmalloc(sizeof(*allmasks), GFP_KERNEL);
7002 printk(KERN_WARNING "Cannot alloc cpumask array\n");
7005 kfree(sched_group_nodes);
7010 tmpmask = (cpumask_t *)allmasks;
7014 sched_group_nodes_bycpu[first_cpu(*cpu_map)] = sched_group_nodes;
7018 * Set up domains for cpus specified by the cpu_map.
7020 for_each_cpu_mask(i, *cpu_map) {
7021 struct sched_domain *sd = NULL, *p;
7022 SCHED_CPUMASK_VAR(nodemask, allmasks);
7024 *nodemask = node_to_cpumask(cpu_to_node(i));
7025 cpus_and(*nodemask, *nodemask, *cpu_map);
7028 if (cpus_weight(*cpu_map) >
7029 SD_NODES_PER_DOMAIN*cpus_weight(*nodemask)) {
7030 sd = &per_cpu(allnodes_domains, i);
7031 SD_INIT(sd, ALLNODES);
7032 set_domain_attribute(sd, attr);
7033 sd->span = *cpu_map;
7034 cpu_to_allnodes_group(i, cpu_map, &sd->groups, tmpmask);
7040 sd = &per_cpu(node_domains, i);
7042 set_domain_attribute(sd, attr);
7043 sched_domain_node_span(cpu_to_node(i), &sd->span);
7047 cpus_and(sd->span, sd->span, *cpu_map);
7051 sd = &per_cpu(phys_domains, i);
7053 set_domain_attribute(sd, attr);
7054 sd->span = *nodemask;
7058 cpu_to_phys_group(i, cpu_map, &sd->groups, tmpmask);
7060 #ifdef CONFIG_SCHED_MC
7062 sd = &per_cpu(core_domains, i);
7064 set_domain_attribute(sd, attr);
7065 sd->span = cpu_coregroup_map(i);
7066 cpus_and(sd->span, sd->span, *cpu_map);
7069 cpu_to_core_group(i, cpu_map, &sd->groups, tmpmask);
7072 #ifdef CONFIG_SCHED_SMT
7074 sd = &per_cpu(cpu_domains, i);
7075 SD_INIT(sd, SIBLING);
7076 set_domain_attribute(sd, attr);
7077 sd->span = per_cpu(cpu_sibling_map, i);
7078 cpus_and(sd->span, sd->span, *cpu_map);
7081 cpu_to_cpu_group(i, cpu_map, &sd->groups, tmpmask);
7085 #ifdef CONFIG_SCHED_SMT
7086 /* Set up CPU (sibling) groups */
7087 for_each_cpu_mask(i, *cpu_map) {
7088 SCHED_CPUMASK_VAR(this_sibling_map, allmasks);
7089 SCHED_CPUMASK_VAR(send_covered, allmasks);
7091 *this_sibling_map = per_cpu(cpu_sibling_map, i);
7092 cpus_and(*this_sibling_map, *this_sibling_map, *cpu_map);
7093 if (i != first_cpu(*this_sibling_map))
7096 init_sched_build_groups(this_sibling_map, cpu_map,
7098 send_covered, tmpmask);
7102 #ifdef CONFIG_SCHED_MC
7103 /* Set up multi-core groups */
7104 for_each_cpu_mask(i, *cpu_map) {
7105 SCHED_CPUMASK_VAR(this_core_map, allmasks);
7106 SCHED_CPUMASK_VAR(send_covered, allmasks);
7108 *this_core_map = cpu_coregroup_map(i);
7109 cpus_and(*this_core_map, *this_core_map, *cpu_map);
7110 if (i != first_cpu(*this_core_map))
7113 init_sched_build_groups(this_core_map, cpu_map,
7115 send_covered, tmpmask);
7119 /* Set up physical groups */
7120 for (i = 0; i < MAX_NUMNODES; i++) {
7121 SCHED_CPUMASK_VAR(nodemask, allmasks);
7122 SCHED_CPUMASK_VAR(send_covered, allmasks);
7124 *nodemask = node_to_cpumask(i);
7125 cpus_and(*nodemask, *nodemask, *cpu_map);
7126 if (cpus_empty(*nodemask))
7129 init_sched_build_groups(nodemask, cpu_map,
7131 send_covered, tmpmask);
7135 /* Set up node groups */
7137 SCHED_CPUMASK_VAR(send_covered, allmasks);
7139 init_sched_build_groups(cpu_map, cpu_map,
7140 &cpu_to_allnodes_group,
7141 send_covered, tmpmask);
7144 for (i = 0; i < MAX_NUMNODES; i++) {
7145 /* Set up node groups */
7146 struct sched_group *sg, *prev;
7147 SCHED_CPUMASK_VAR(nodemask, allmasks);
7148 SCHED_CPUMASK_VAR(domainspan, allmasks);
7149 SCHED_CPUMASK_VAR(covered, allmasks);
7152 *nodemask = node_to_cpumask(i);
7153 cpus_clear(*covered);
7155 cpus_and(*nodemask, *nodemask, *cpu_map);
7156 if (cpus_empty(*nodemask)) {
7157 sched_group_nodes[i] = NULL;
7161 sched_domain_node_span(i, domainspan);
7162 cpus_and(*domainspan, *domainspan, *cpu_map);
7164 sg = kmalloc_node(sizeof(struct sched_group), GFP_KERNEL, i);
7166 printk(KERN_WARNING "Can not alloc domain group for "
7170 sched_group_nodes[i] = sg;
7171 for_each_cpu_mask(j, *nodemask) {
7172 struct sched_domain *sd;
7174 sd = &per_cpu(node_domains, j);
7177 sg->__cpu_power = 0;
7178 sg->cpumask = *nodemask;
7180 cpus_or(*covered, *covered, *nodemask);
7183 for (j = 0; j < MAX_NUMNODES; j++) {
7184 SCHED_CPUMASK_VAR(notcovered, allmasks);
7185 int n = (i + j) % MAX_NUMNODES;
7186 node_to_cpumask_ptr(pnodemask, n);
7188 cpus_complement(*notcovered, *covered);
7189 cpus_and(*tmpmask, *notcovered, *cpu_map);
7190 cpus_and(*tmpmask, *tmpmask, *domainspan);
7191 if (cpus_empty(*tmpmask))
7194 cpus_and(*tmpmask, *tmpmask, *pnodemask);
7195 if (cpus_empty(*tmpmask))
7198 sg = kmalloc_node(sizeof(struct sched_group),
7202 "Can not alloc domain group for node %d\n", j);
7205 sg->__cpu_power = 0;
7206 sg->cpumask = *tmpmask;
7207 sg->next = prev->next;
7208 cpus_or(*covered, *covered, *tmpmask);
7215 /* Calculate CPU power for physical packages and nodes */
7216 #ifdef CONFIG_SCHED_SMT
7217 for_each_cpu_mask(i, *cpu_map) {
7218 struct sched_domain *sd = &per_cpu(cpu_domains, i);
7220 init_sched_groups_power(i, sd);
7223 #ifdef CONFIG_SCHED_MC
7224 for_each_cpu_mask(i, *cpu_map) {
7225 struct sched_domain *sd = &per_cpu(core_domains, i);
7227 init_sched_groups_power(i, sd);
7231 for_each_cpu_mask(i, *cpu_map) {
7232 struct sched_domain *sd = &per_cpu(phys_domains, i);
7234 init_sched_groups_power(i, sd);
7238 for (i = 0; i < MAX_NUMNODES; i++)
7239 init_numa_sched_groups_power(sched_group_nodes[i]);
7242 struct sched_group *sg;
7244 cpu_to_allnodes_group(first_cpu(*cpu_map), cpu_map, &sg,
7246 init_numa_sched_groups_power(sg);
7250 /* Attach the domains */
7251 for_each_cpu_mask(i, *cpu_map) {
7252 struct sched_domain *sd;
7253 #ifdef CONFIG_SCHED_SMT
7254 sd = &per_cpu(cpu_domains, i);
7255 #elif defined(CONFIG_SCHED_MC)
7256 sd = &per_cpu(core_domains, i);
7258 sd = &per_cpu(phys_domains, i);
7260 cpu_attach_domain(sd, rd, i);
7263 SCHED_CPUMASK_FREE((void *)allmasks);
7268 free_sched_groups(cpu_map, tmpmask);
7269 SCHED_CPUMASK_FREE((void *)allmasks);
7274 static int build_sched_domains(const cpumask_t *cpu_map)
7276 return __build_sched_domains(cpu_map, NULL);
7279 static cpumask_t *doms_cur; /* current sched domains */
7280 static int ndoms_cur; /* number of sched domains in 'doms_cur' */
7281 static struct sched_domain_attr *dattr_cur;
7282 /* attribues of custom domains in 'doms_cur' */
7285 * Special case: If a kmalloc of a doms_cur partition (array of
7286 * cpumask_t) fails, then fallback to a single sched domain,
7287 * as determined by the single cpumask_t fallback_doms.
7289 static cpumask_t fallback_doms;
7291 void __attribute__((weak)) arch_update_cpu_topology(void)
7296 * Free current domain masks.
7297 * Called after all cpus are attached to NULL domain.
7299 static void free_sched_domains(void)
7302 if (doms_cur != &fallback_doms)
7304 doms_cur = &fallback_doms;
7308 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
7309 * For now this just excludes isolated cpus, but could be used to
7310 * exclude other special cases in the future.
7312 static int arch_init_sched_domains(const cpumask_t *cpu_map)
7316 arch_update_cpu_topology();
7318 doms_cur = kmalloc(sizeof(cpumask_t), GFP_KERNEL);
7320 doms_cur = &fallback_doms;
7321 cpus_andnot(*doms_cur, *cpu_map, cpu_isolated_map);
7323 err = build_sched_domains(doms_cur);
7324 register_sched_domain_sysctl();
7329 static void arch_destroy_sched_domains(const cpumask_t *cpu_map,
7332 free_sched_groups(cpu_map, tmpmask);
7336 * Detach sched domains from a group of cpus specified in cpu_map
7337 * These cpus will now be attached to the NULL domain
7339 static void detach_destroy_domains(const cpumask_t *cpu_map)
7344 unregister_sched_domain_sysctl();
7346 for_each_cpu_mask(i, *cpu_map)
7347 cpu_attach_domain(NULL, &def_root_domain, i);
7348 synchronize_sched();
7349 arch_destroy_sched_domains(cpu_map, &tmpmask);
7352 /* handle null as "default" */
7353 static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
7354 struct sched_domain_attr *new, int idx_new)
7356 struct sched_domain_attr tmp;
7363 return !memcmp(cur ? (cur + idx_cur) : &tmp,
7364 new ? (new + idx_new) : &tmp,
7365 sizeof(struct sched_domain_attr));
7369 * Partition sched domains as specified by the 'ndoms_new'
7370 * cpumasks in the array doms_new[] of cpumasks. This compares
7371 * doms_new[] to the current sched domain partitioning, doms_cur[].
7372 * It destroys each deleted domain and builds each new domain.
7374 * 'doms_new' is an array of cpumask_t's of length 'ndoms_new'.
7375 * The masks don't intersect (don't overlap.) We should setup one
7376 * sched domain for each mask. CPUs not in any of the cpumasks will
7377 * not be load balanced. If the same cpumask appears both in the
7378 * current 'doms_cur' domains and in the new 'doms_new', we can leave
7381 * The passed in 'doms_new' should be kmalloc'd. This routine takes
7382 * ownership of it and will kfree it when done with it. If the caller
7383 * failed the kmalloc call, then it can pass in doms_new == NULL,
7384 * and partition_sched_domains() will fallback to the single partition
7387 * Call with hotplug lock held
7389 void partition_sched_domains(int ndoms_new, cpumask_t *doms_new,
7390 struct sched_domain_attr *dattr_new)
7394 mutex_lock(&sched_domains_mutex);
7396 /* always unregister in case we don't destroy any domains */
7397 unregister_sched_domain_sysctl();
7399 if (doms_new == NULL) {
7401 doms_new = &fallback_doms;
7402 cpus_andnot(doms_new[0], cpu_online_map, cpu_isolated_map);
7406 /* Destroy deleted domains */
7407 for (i = 0; i < ndoms_cur; i++) {
7408 for (j = 0; j < ndoms_new; j++) {
7409 if (cpus_equal(doms_cur[i], doms_new[j])
7410 && dattrs_equal(dattr_cur, i, dattr_new, j))
7413 /* no match - a current sched domain not in new doms_new[] */
7414 detach_destroy_domains(doms_cur + i);
7419 /* Build new domains */
7420 for (i = 0; i < ndoms_new; i++) {
7421 for (j = 0; j < ndoms_cur; j++) {
7422 if (cpus_equal(doms_new[i], doms_cur[j])
7423 && dattrs_equal(dattr_new, i, dattr_cur, j))
7426 /* no match - add a new doms_new */
7427 __build_sched_domains(doms_new + i,
7428 dattr_new ? dattr_new + i : NULL);
7433 /* Remember the new sched domains */
7434 if (doms_cur != &fallback_doms)
7436 kfree(dattr_cur); /* kfree(NULL) is safe */
7437 doms_cur = doms_new;
7438 dattr_cur = dattr_new;
7439 ndoms_cur = ndoms_new;
7441 register_sched_domain_sysctl();
7443 mutex_unlock(&sched_domains_mutex);
7446 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
7447 int arch_reinit_sched_domains(void)
7452 mutex_lock(&sched_domains_mutex);
7453 detach_destroy_domains(&cpu_online_map);
7454 free_sched_domains();
7455 err = arch_init_sched_domains(&cpu_online_map);
7456 mutex_unlock(&sched_domains_mutex);
7462 static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt)
7466 if (buf[0] != '0' && buf[0] != '1')
7470 sched_smt_power_savings = (buf[0] == '1');
7472 sched_mc_power_savings = (buf[0] == '1');
7474 ret = arch_reinit_sched_domains();
7476 return ret ? ret : count;
7479 #ifdef CONFIG_SCHED_MC
7480 static ssize_t sched_mc_power_savings_show(struct sys_device *dev, char *page)
7482 return sprintf(page, "%u\n", sched_mc_power_savings);
7484 static ssize_t sched_mc_power_savings_store(struct sys_device *dev,
7485 const char *buf, size_t count)
7487 return sched_power_savings_store(buf, count, 0);
7489 static SYSDEV_ATTR(sched_mc_power_savings, 0644, sched_mc_power_savings_show,
7490 sched_mc_power_savings_store);
7493 #ifdef CONFIG_SCHED_SMT
7494 static ssize_t sched_smt_power_savings_show(struct sys_device *dev, char *page)
7496 return sprintf(page, "%u\n", sched_smt_power_savings);
7498 static ssize_t sched_smt_power_savings_store(struct sys_device *dev,
7499 const char *buf, size_t count)
7501 return sched_power_savings_store(buf, count, 1);
7503 static SYSDEV_ATTR(sched_smt_power_savings, 0644, sched_smt_power_savings_show,
7504 sched_smt_power_savings_store);
7507 int sched_create_sysfs_power_savings_entries(struct sysdev_class *cls)
7511 #ifdef CONFIG_SCHED_SMT
7513 err = sysfs_create_file(&cls->kset.kobj,
7514 &attr_sched_smt_power_savings.attr);
7516 #ifdef CONFIG_SCHED_MC
7517 if (!err && mc_capable())
7518 err = sysfs_create_file(&cls->kset.kobj,
7519 &attr_sched_mc_power_savings.attr);
7526 * Force a reinitialization of the sched domains hierarchy. The domains
7527 * and groups cannot be updated in place without racing with the balancing
7528 * code, so we temporarily attach all running cpus to the NULL domain
7529 * which will prevent rebalancing while the sched domains are recalculated.
7531 static int update_sched_domains(struct notifier_block *nfb,
7532 unsigned long action, void *hcpu)
7535 case CPU_UP_PREPARE:
7536 case CPU_UP_PREPARE_FROZEN:
7537 case CPU_DOWN_PREPARE:
7538 case CPU_DOWN_PREPARE_FROZEN:
7539 detach_destroy_domains(&cpu_online_map);
7540 free_sched_domains();
7543 case CPU_UP_CANCELED:
7544 case CPU_UP_CANCELED_FROZEN:
7545 case CPU_DOWN_FAILED:
7546 case CPU_DOWN_FAILED_FROZEN:
7548 case CPU_ONLINE_FROZEN:
7550 case CPU_DEAD_FROZEN:
7552 * Fall through and re-initialise the domains.
7559 #ifndef CONFIG_CPUSETS
7561 * Create default domain partitioning if cpusets are disabled.
7562 * Otherwise we let cpusets rebuild the domains based on the
7566 /* The hotplug lock is already held by cpu_up/cpu_down */
7567 arch_init_sched_domains(&cpu_online_map);
7573 void __init sched_init_smp(void)
7575 cpumask_t non_isolated_cpus;
7577 #if defined(CONFIG_NUMA)
7578 sched_group_nodes_bycpu = kzalloc(nr_cpu_ids * sizeof(void **),
7580 BUG_ON(sched_group_nodes_bycpu == NULL);
7583 mutex_lock(&sched_domains_mutex);
7584 arch_init_sched_domains(&cpu_online_map);
7585 cpus_andnot(non_isolated_cpus, cpu_possible_map, cpu_isolated_map);
7586 if (cpus_empty(non_isolated_cpus))
7587 cpu_set(smp_processor_id(), non_isolated_cpus);
7588 mutex_unlock(&sched_domains_mutex);
7590 /* XXX: Theoretical race here - CPU may be hotplugged now */
7591 hotcpu_notifier(update_sched_domains, 0);
7594 /* Move init over to a non-isolated CPU */
7595 if (set_cpus_allowed_ptr(current, &non_isolated_cpus) < 0)
7597 sched_init_granularity();
7600 void __init sched_init_smp(void)
7602 sched_init_granularity();
7604 #endif /* CONFIG_SMP */
7606 int in_sched_functions(unsigned long addr)
7608 return in_lock_functions(addr) ||
7609 (addr >= (unsigned long)__sched_text_start
7610 && addr < (unsigned long)__sched_text_end);
7613 static void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq)
7615 cfs_rq->tasks_timeline = RB_ROOT;
7616 INIT_LIST_HEAD(&cfs_rq->tasks);
7617 #ifdef CONFIG_FAIR_GROUP_SCHED
7620 cfs_rq->min_vruntime = (u64)(-(1LL << 20));
7623 static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
7625 struct rt_prio_array *array;
7628 array = &rt_rq->active;
7629 for (i = 0; i < MAX_RT_PRIO; i++) {
7630 INIT_LIST_HEAD(array->queue + i);
7631 __clear_bit(i, array->bitmap);
7633 /* delimiter for bitsearch: */
7634 __set_bit(MAX_RT_PRIO, array->bitmap);
7636 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
7637 rt_rq->highest_prio = MAX_RT_PRIO;
7640 rt_rq->rt_nr_migratory = 0;
7641 rt_rq->overloaded = 0;
7645 rt_rq->rt_throttled = 0;
7646 rt_rq->rt_runtime = 0;
7647 spin_lock_init(&rt_rq->rt_runtime_lock);
7649 #ifdef CONFIG_RT_GROUP_SCHED
7650 rt_rq->rt_nr_boosted = 0;
7655 #ifdef CONFIG_FAIR_GROUP_SCHED
7656 static void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
7657 struct sched_entity *se, int cpu, int add,
7658 struct sched_entity *parent)
7660 struct rq *rq = cpu_rq(cpu);
7661 tg->cfs_rq[cpu] = cfs_rq;
7662 init_cfs_rq(cfs_rq, rq);
7665 list_add(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list);
7668 /* se could be NULL for init_task_group */
7673 se->cfs_rq = &rq->cfs;
7675 se->cfs_rq = parent->my_q;
7678 se->load.weight = tg->shares;
7679 se->load.inv_weight = 0;
7680 se->parent = parent;
7684 #ifdef CONFIG_RT_GROUP_SCHED
7685 static void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
7686 struct sched_rt_entity *rt_se, int cpu, int add,
7687 struct sched_rt_entity *parent)
7689 struct rq *rq = cpu_rq(cpu);
7691 tg->rt_rq[cpu] = rt_rq;
7692 init_rt_rq(rt_rq, rq);
7694 rt_rq->rt_se = rt_se;
7695 rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime;
7697 list_add(&rt_rq->leaf_rt_rq_list, &rq->leaf_rt_rq_list);
7699 tg->rt_se[cpu] = rt_se;
7704 rt_se->rt_rq = &rq->rt;
7706 rt_se->rt_rq = parent->my_q;
7708 rt_se->my_q = rt_rq;
7709 rt_se->parent = parent;
7710 INIT_LIST_HEAD(&rt_se->run_list);
7714 void __init sched_init(void)
7717 unsigned long alloc_size = 0, ptr;
7719 #ifdef CONFIG_FAIR_GROUP_SCHED
7720 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
7722 #ifdef CONFIG_RT_GROUP_SCHED
7723 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
7725 #ifdef CONFIG_USER_SCHED
7729 * As sched_init() is called before page_alloc is setup,
7730 * we use alloc_bootmem().
7733 ptr = (unsigned long)alloc_bootmem(alloc_size);
7735 #ifdef CONFIG_FAIR_GROUP_SCHED
7736 init_task_group.se = (struct sched_entity **)ptr;
7737 ptr += nr_cpu_ids * sizeof(void **);
7739 init_task_group.cfs_rq = (struct cfs_rq **)ptr;
7740 ptr += nr_cpu_ids * sizeof(void **);
7742 #ifdef CONFIG_USER_SCHED
7743 root_task_group.se = (struct sched_entity **)ptr;
7744 ptr += nr_cpu_ids * sizeof(void **);
7746 root_task_group.cfs_rq = (struct cfs_rq **)ptr;
7747 ptr += nr_cpu_ids * sizeof(void **);
7750 #ifdef CONFIG_RT_GROUP_SCHED
7751 init_task_group.rt_se = (struct sched_rt_entity **)ptr;
7752 ptr += nr_cpu_ids * sizeof(void **);
7754 init_task_group.rt_rq = (struct rt_rq **)ptr;
7755 ptr += nr_cpu_ids * sizeof(void **);
7757 #ifdef CONFIG_USER_SCHED
7758 root_task_group.rt_se = (struct sched_rt_entity **)ptr;
7759 ptr += nr_cpu_ids * sizeof(void **);
7761 root_task_group.rt_rq = (struct rt_rq **)ptr;
7762 ptr += nr_cpu_ids * sizeof(void **);
7768 init_defrootdomain();
7771 init_rt_bandwidth(&def_rt_bandwidth,
7772 global_rt_period(), global_rt_runtime());
7774 #ifdef CONFIG_RT_GROUP_SCHED
7775 init_rt_bandwidth(&init_task_group.rt_bandwidth,
7776 global_rt_period(), global_rt_runtime());
7777 #ifdef CONFIG_USER_SCHED
7778 init_rt_bandwidth(&root_task_group.rt_bandwidth,
7779 global_rt_period(), RUNTIME_INF);
7783 #ifdef CONFIG_GROUP_SCHED
7784 list_add(&init_task_group.list, &task_groups);
7785 INIT_LIST_HEAD(&init_task_group.children);
7787 #ifdef CONFIG_USER_SCHED
7788 INIT_LIST_HEAD(&root_task_group.children);
7789 init_task_group.parent = &root_task_group;
7790 list_add(&init_task_group.siblings, &root_task_group.children);
7794 for_each_possible_cpu(i) {
7798 spin_lock_init(&rq->lock);
7799 lockdep_set_class(&rq->lock, &rq->rq_lock_key);
7801 init_cfs_rq(&rq->cfs, rq);
7802 init_rt_rq(&rq->rt, rq);
7803 #ifdef CONFIG_FAIR_GROUP_SCHED
7804 init_task_group.shares = init_task_group_load;
7805 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
7806 #ifdef CONFIG_CGROUP_SCHED
7808 * How much cpu bandwidth does init_task_group get?
7810 * In case of task-groups formed thr' the cgroup filesystem, it
7811 * gets 100% of the cpu resources in the system. This overall
7812 * system cpu resource is divided among the tasks of
7813 * init_task_group and its child task-groups in a fair manner,
7814 * based on each entity's (task or task-group's) weight
7815 * (se->load.weight).
7817 * In other words, if init_task_group has 10 tasks of weight
7818 * 1024) and two child groups A0 and A1 (of weight 1024 each),
7819 * then A0's share of the cpu resource is:
7821 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
7823 * We achieve this by letting init_task_group's tasks sit
7824 * directly in rq->cfs (i.e init_task_group->se[] = NULL).
7826 init_tg_cfs_entry(&init_task_group, &rq->cfs, NULL, i, 1, NULL);
7827 #elif defined CONFIG_USER_SCHED
7828 root_task_group.shares = NICE_0_LOAD;
7829 init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, 0, NULL);
7831 * In case of task-groups formed thr' the user id of tasks,
7832 * init_task_group represents tasks belonging to root user.
7833 * Hence it forms a sibling of all subsequent groups formed.
7834 * In this case, init_task_group gets only a fraction of overall
7835 * system cpu resource, based on the weight assigned to root
7836 * user's cpu share (INIT_TASK_GROUP_LOAD). This is accomplished
7837 * by letting tasks of init_task_group sit in a separate cfs_rq
7838 * (init_cfs_rq) and having one entity represent this group of
7839 * tasks in rq->cfs (i.e init_task_group->se[] != NULL).
7841 init_tg_cfs_entry(&init_task_group,
7842 &per_cpu(init_cfs_rq, i),
7843 &per_cpu(init_sched_entity, i), i, 1,
7844 root_task_group.se[i]);
7847 #endif /* CONFIG_FAIR_GROUP_SCHED */
7849 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime;
7850 #ifdef CONFIG_RT_GROUP_SCHED
7851 INIT_LIST_HEAD(&rq->leaf_rt_rq_list);
7852 #ifdef CONFIG_CGROUP_SCHED
7853 init_tg_rt_entry(&init_task_group, &rq->rt, NULL, i, 1, NULL);
7854 #elif defined CONFIG_USER_SCHED
7855 init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, 0, NULL);
7856 init_tg_rt_entry(&init_task_group,
7857 &per_cpu(init_rt_rq, i),
7858 &per_cpu(init_sched_rt_entity, i), i, 1,
7859 root_task_group.rt_se[i]);
7863 for (j = 0; j < CPU_LOAD_IDX_MAX; j++)
7864 rq->cpu_load[j] = 0;
7868 rq->active_balance = 0;
7869 rq->next_balance = jiffies;
7872 rq->migration_thread = NULL;
7873 INIT_LIST_HEAD(&rq->migration_queue);
7874 rq_attach_root(rq, &def_root_domain);
7877 atomic_set(&rq->nr_iowait, 0);
7880 set_load_weight(&init_task);
7882 #ifdef CONFIG_PREEMPT_NOTIFIERS
7883 INIT_HLIST_HEAD(&init_task.preempt_notifiers);
7887 open_softirq(SCHED_SOFTIRQ, run_rebalance_domains, NULL);
7890 #ifdef CONFIG_RT_MUTEXES
7891 plist_head_init(&init_task.pi_waiters, &init_task.pi_lock);
7895 * The boot idle thread does lazy MMU switching as well:
7897 atomic_inc(&init_mm.mm_count);
7898 enter_lazy_tlb(&init_mm, current);
7901 * Make us the idle thread. Technically, schedule() should not be
7902 * called from this thread, however somewhere below it might be,
7903 * but because we are the idle thread, we just pick up running again
7904 * when this runqueue becomes "idle".
7906 init_idle(current, smp_processor_id());
7908 * During early bootup we pretend to be a normal task:
7910 current->sched_class = &fair_sched_class;
7912 scheduler_running = 1;
7915 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
7916 void __might_sleep(char *file, int line)
7919 static unsigned long prev_jiffy; /* ratelimiting */
7921 if ((in_atomic() || irqs_disabled()) &&
7922 system_state == SYSTEM_RUNNING && !oops_in_progress) {
7923 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
7925 prev_jiffy = jiffies;
7926 printk(KERN_ERR "BUG: sleeping function called from invalid"
7927 " context at %s:%d\n", file, line);
7928 printk("in_atomic():%d, irqs_disabled():%d\n",
7929 in_atomic(), irqs_disabled());
7930 debug_show_held_locks(current);
7931 if (irqs_disabled())
7932 print_irqtrace_events(current);
7937 EXPORT_SYMBOL(__might_sleep);
7940 #ifdef CONFIG_MAGIC_SYSRQ
7941 static void normalize_task(struct rq *rq, struct task_struct *p)
7945 update_rq_clock(rq);
7946 on_rq = p->se.on_rq;
7948 deactivate_task(rq, p, 0);
7949 __setscheduler(rq, p, SCHED_NORMAL, 0);
7951 activate_task(rq, p, 0);
7952 resched_task(rq->curr);
7956 void normalize_rt_tasks(void)
7958 struct task_struct *g, *p;
7959 unsigned long flags;
7962 read_lock_irqsave(&tasklist_lock, flags);
7963 do_each_thread(g, p) {
7965 * Only normalize user tasks:
7970 p->se.exec_start = 0;
7971 #ifdef CONFIG_SCHEDSTATS
7972 p->se.wait_start = 0;
7973 p->se.sleep_start = 0;
7974 p->se.block_start = 0;
7979 * Renice negative nice level userspace
7982 if (TASK_NICE(p) < 0 && p->mm)
7983 set_user_nice(p, 0);
7987 spin_lock(&p->pi_lock);
7988 rq = __task_rq_lock(p);
7990 normalize_task(rq, p);
7992 __task_rq_unlock(rq);
7993 spin_unlock(&p->pi_lock);
7994 } while_each_thread(g, p);
7996 read_unlock_irqrestore(&tasklist_lock, flags);
7999 #endif /* CONFIG_MAGIC_SYSRQ */
8003 * These functions are only useful for the IA64 MCA handling.
8005 * They can only be called when the whole system has been
8006 * stopped - every CPU needs to be quiescent, and no scheduling
8007 * activity can take place. Using them for anything else would
8008 * be a serious bug, and as a result, they aren't even visible
8009 * under any other configuration.
8013 * curr_task - return the current task for a given cpu.
8014 * @cpu: the processor in question.
8016 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
8018 struct task_struct *curr_task(int cpu)
8020 return cpu_curr(cpu);
8024 * set_curr_task - set the current task for a given cpu.
8025 * @cpu: the processor in question.
8026 * @p: the task pointer to set.
8028 * Description: This function must only be used when non-maskable interrupts
8029 * are serviced on a separate stack. It allows the architecture to switch the
8030 * notion of the current task on a cpu in a non-blocking manner. This function
8031 * must be called with all CPU's synchronized, and interrupts disabled, the
8032 * and caller must save the original value of the current task (see
8033 * curr_task() above) and restore that value before reenabling interrupts and
8034 * re-starting the system.
8036 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
8038 void set_curr_task(int cpu, struct task_struct *p)
8045 #ifdef CONFIG_FAIR_GROUP_SCHED
8046 static void free_fair_sched_group(struct task_group *tg)
8050 for_each_possible_cpu(i) {
8052 kfree(tg->cfs_rq[i]);
8062 int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
8064 struct cfs_rq *cfs_rq;
8065 struct sched_entity *se, *parent_se;
8069 tg->cfs_rq = kzalloc(sizeof(cfs_rq) * nr_cpu_ids, GFP_KERNEL);
8072 tg->se = kzalloc(sizeof(se) * nr_cpu_ids, GFP_KERNEL);
8076 tg->shares = NICE_0_LOAD;
8078 for_each_possible_cpu(i) {
8081 cfs_rq = kmalloc_node(sizeof(struct cfs_rq),
8082 GFP_KERNEL|__GFP_ZERO, cpu_to_node(i));
8086 se = kmalloc_node(sizeof(struct sched_entity),
8087 GFP_KERNEL|__GFP_ZERO, cpu_to_node(i));
8091 parent_se = parent ? parent->se[i] : NULL;
8092 init_tg_cfs_entry(tg, cfs_rq, se, i, 0, parent_se);
8101 static inline void register_fair_sched_group(struct task_group *tg, int cpu)
8103 list_add_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list,
8104 &cpu_rq(cpu)->leaf_cfs_rq_list);
8107 static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
8109 list_del_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list);
8112 static inline void free_fair_sched_group(struct task_group *tg)
8117 int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
8122 static inline void register_fair_sched_group(struct task_group *tg, int cpu)
8126 static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
8131 #ifdef CONFIG_RT_GROUP_SCHED
8132 static void free_rt_sched_group(struct task_group *tg)
8136 destroy_rt_bandwidth(&tg->rt_bandwidth);
8138 for_each_possible_cpu(i) {
8140 kfree(tg->rt_rq[i]);
8142 kfree(tg->rt_se[i]);
8150 int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
8152 struct rt_rq *rt_rq;
8153 struct sched_rt_entity *rt_se, *parent_se;
8157 tg->rt_rq = kzalloc(sizeof(rt_rq) * nr_cpu_ids, GFP_KERNEL);
8160 tg->rt_se = kzalloc(sizeof(rt_se) * nr_cpu_ids, GFP_KERNEL);
8164 init_rt_bandwidth(&tg->rt_bandwidth,
8165 ktime_to_ns(def_rt_bandwidth.rt_period), 0);
8167 for_each_possible_cpu(i) {
8170 rt_rq = kmalloc_node(sizeof(struct rt_rq),
8171 GFP_KERNEL|__GFP_ZERO, cpu_to_node(i));
8175 rt_se = kmalloc_node(sizeof(struct sched_rt_entity),
8176 GFP_KERNEL|__GFP_ZERO, cpu_to_node(i));
8180 parent_se = parent ? parent->rt_se[i] : NULL;
8181 init_tg_rt_entry(tg, rt_rq, rt_se, i, 0, parent_se);
8190 static inline void register_rt_sched_group(struct task_group *tg, int cpu)
8192 list_add_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list,
8193 &cpu_rq(cpu)->leaf_rt_rq_list);
8196 static inline void unregister_rt_sched_group(struct task_group *tg, int cpu)
8198 list_del_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list);
8201 static inline void free_rt_sched_group(struct task_group *tg)
8206 int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
8211 static inline void register_rt_sched_group(struct task_group *tg, int cpu)
8215 static inline void unregister_rt_sched_group(struct task_group *tg, int cpu)
8220 #ifdef CONFIG_GROUP_SCHED
8221 static void free_sched_group(struct task_group *tg)
8223 free_fair_sched_group(tg);
8224 free_rt_sched_group(tg);
8228 /* allocate runqueue etc for a new task group */
8229 struct task_group *sched_create_group(struct task_group *parent)
8231 struct task_group *tg;
8232 unsigned long flags;
8235 tg = kzalloc(sizeof(*tg), GFP_KERNEL);
8237 return ERR_PTR(-ENOMEM);
8239 if (!alloc_fair_sched_group(tg, parent))
8242 if (!alloc_rt_sched_group(tg, parent))
8245 spin_lock_irqsave(&task_group_lock, flags);
8246 for_each_possible_cpu(i) {
8247 register_fair_sched_group(tg, i);
8248 register_rt_sched_group(tg, i);
8250 list_add_rcu(&tg->list, &task_groups);
8252 WARN_ON(!parent); /* root should already exist */
8254 tg->parent = parent;
8255 list_add_rcu(&tg->siblings, &parent->children);
8256 INIT_LIST_HEAD(&tg->children);
8257 spin_unlock_irqrestore(&task_group_lock, flags);
8262 free_sched_group(tg);
8263 return ERR_PTR(-ENOMEM);
8266 /* rcu callback to free various structures associated with a task group */
8267 static void free_sched_group_rcu(struct rcu_head *rhp)
8269 /* now it should be safe to free those cfs_rqs */
8270 free_sched_group(container_of(rhp, struct task_group, rcu));
8273 /* Destroy runqueue etc associated with a task group */
8274 void sched_destroy_group(struct task_group *tg)
8276 unsigned long flags;
8279 spin_lock_irqsave(&task_group_lock, flags);
8280 for_each_possible_cpu(i) {
8281 unregister_fair_sched_group(tg, i);
8282 unregister_rt_sched_group(tg, i);
8284 list_del_rcu(&tg->list);
8285 list_del_rcu(&tg->siblings);
8286 spin_unlock_irqrestore(&task_group_lock, flags);
8288 /* wait for possible concurrent references to cfs_rqs complete */
8289 call_rcu(&tg->rcu, free_sched_group_rcu);
8292 /* change task's runqueue when it moves between groups.
8293 * The caller of this function should have put the task in its new group
8294 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
8295 * reflect its new group.
8297 void sched_move_task(struct task_struct *tsk)
8300 unsigned long flags;
8303 rq = task_rq_lock(tsk, &flags);
8305 update_rq_clock(rq);
8307 running = task_current(rq, tsk);
8308 on_rq = tsk->se.on_rq;
8311 dequeue_task(rq, tsk, 0);
8312 if (unlikely(running))
8313 tsk->sched_class->put_prev_task(rq, tsk);
8315 set_task_rq(tsk, task_cpu(tsk));
8317 #ifdef CONFIG_FAIR_GROUP_SCHED
8318 if (tsk->sched_class->moved_group)
8319 tsk->sched_class->moved_group(tsk);
8322 if (unlikely(running))
8323 tsk->sched_class->set_curr_task(rq);
8325 enqueue_task(rq, tsk, 0);
8327 task_rq_unlock(rq, &flags);
8331 #ifdef CONFIG_FAIR_GROUP_SCHED
8332 static void set_se_shares(struct sched_entity *se, unsigned long shares)
8334 struct cfs_rq *cfs_rq = se->cfs_rq;
8335 struct rq *rq = cfs_rq->rq;
8338 spin_lock_irq(&rq->lock);
8342 dequeue_entity(cfs_rq, se, 0);
8344 se->load.weight = shares;
8345 se->load.inv_weight = 0;
8348 enqueue_entity(cfs_rq, se, 0);
8350 spin_unlock_irq(&rq->lock);
8353 static DEFINE_MUTEX(shares_mutex);
8355 int sched_group_set_shares(struct task_group *tg, unsigned long shares)
8358 unsigned long flags;
8361 * We can't change the weight of the root cgroup.
8366 if (shares < MIN_SHARES)
8367 shares = MIN_SHARES;
8368 else if (shares > MAX_SHARES)
8369 shares = MAX_SHARES;
8371 mutex_lock(&shares_mutex);
8372 if (tg->shares == shares)
8375 spin_lock_irqsave(&task_group_lock, flags);
8376 for_each_possible_cpu(i)
8377 unregister_fair_sched_group(tg, i);
8378 list_del_rcu(&tg->siblings);
8379 spin_unlock_irqrestore(&task_group_lock, flags);
8381 /* wait for any ongoing reference to this group to finish */
8382 synchronize_sched();
8385 * Now we are free to modify the group's share on each cpu
8386 * w/o tripping rebalance_share or load_balance_fair.
8388 tg->shares = shares;
8389 for_each_possible_cpu(i)
8390 set_se_shares(tg->se[i], shares);
8393 * Enable load balance activity on this group, by inserting it back on
8394 * each cpu's rq->leaf_cfs_rq_list.
8396 spin_lock_irqsave(&task_group_lock, flags);
8397 for_each_possible_cpu(i)
8398 register_fair_sched_group(tg, i);
8399 list_add_rcu(&tg->siblings, &tg->parent->children);
8400 spin_unlock_irqrestore(&task_group_lock, flags);
8402 mutex_unlock(&shares_mutex);
8406 unsigned long sched_group_shares(struct task_group *tg)
8412 #ifdef CONFIG_RT_GROUP_SCHED
8414 * Ensure that the real time constraints are schedulable.
8416 static DEFINE_MUTEX(rt_constraints_mutex);
8418 static unsigned long to_ratio(u64 period, u64 runtime)
8420 if (runtime == RUNTIME_INF)
8423 return div64_u64(runtime << 16, period);
8426 #ifdef CONFIG_CGROUP_SCHED
8427 static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
8429 struct task_group *tgi, *parent = tg ? tg->parent : NULL;
8430 unsigned long total = 0;
8433 if (global_rt_period() < period)
8436 return to_ratio(period, runtime) <
8437 to_ratio(global_rt_period(), global_rt_runtime());
8440 if (ktime_to_ns(parent->rt_bandwidth.rt_period) < period)
8444 list_for_each_entry_rcu(tgi, &parent->children, siblings) {
8448 total += to_ratio(ktime_to_ns(tgi->rt_bandwidth.rt_period),
8449 tgi->rt_bandwidth.rt_runtime);
8453 return total + to_ratio(period, runtime) <
8454 to_ratio(ktime_to_ns(parent->rt_bandwidth.rt_period),
8455 parent->rt_bandwidth.rt_runtime);
8457 #elif defined CONFIG_USER_SCHED
8458 static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
8460 struct task_group *tgi;
8461 unsigned long total = 0;
8462 unsigned long global_ratio =
8463 to_ratio(global_rt_period(), global_rt_runtime());
8466 list_for_each_entry_rcu(tgi, &task_groups, list) {
8470 total += to_ratio(ktime_to_ns(tgi->rt_bandwidth.rt_period),
8471 tgi->rt_bandwidth.rt_runtime);
8475 return total + to_ratio(period, runtime) < global_ratio;
8479 /* Must be called with tasklist_lock held */
8480 static inline int tg_has_rt_tasks(struct task_group *tg)
8482 struct task_struct *g, *p;
8483 do_each_thread(g, p) {
8484 if (rt_task(p) && rt_rq_of_se(&p->rt)->tg == tg)
8486 } while_each_thread(g, p);
8490 static int tg_set_bandwidth(struct task_group *tg,
8491 u64 rt_period, u64 rt_runtime)
8495 mutex_lock(&rt_constraints_mutex);
8496 read_lock(&tasklist_lock);
8497 if (rt_runtime == 0 && tg_has_rt_tasks(tg)) {
8501 if (!__rt_schedulable(tg, rt_period, rt_runtime)) {
8506 spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock);
8507 tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period);
8508 tg->rt_bandwidth.rt_runtime = rt_runtime;
8510 for_each_possible_cpu(i) {
8511 struct rt_rq *rt_rq = tg->rt_rq[i];
8513 spin_lock(&rt_rq->rt_runtime_lock);
8514 rt_rq->rt_runtime = rt_runtime;
8515 spin_unlock(&rt_rq->rt_runtime_lock);
8517 spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock);
8519 read_unlock(&tasklist_lock);
8520 mutex_unlock(&rt_constraints_mutex);
8525 int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us)
8527 u64 rt_runtime, rt_period;
8529 rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period);
8530 rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC;
8531 if (rt_runtime_us < 0)
8532 rt_runtime = RUNTIME_INF;
8534 return tg_set_bandwidth(tg, rt_period, rt_runtime);
8537 long sched_group_rt_runtime(struct task_group *tg)
8541 if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF)
8544 rt_runtime_us = tg->rt_bandwidth.rt_runtime;
8545 do_div(rt_runtime_us, NSEC_PER_USEC);
8546 return rt_runtime_us;
8549 int sched_group_set_rt_period(struct task_group *tg, long rt_period_us)
8551 u64 rt_runtime, rt_period;
8553 rt_period = (u64)rt_period_us * NSEC_PER_USEC;
8554 rt_runtime = tg->rt_bandwidth.rt_runtime;
8559 return tg_set_bandwidth(tg, rt_period, rt_runtime);
8562 long sched_group_rt_period(struct task_group *tg)
8566 rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period);
8567 do_div(rt_period_us, NSEC_PER_USEC);
8568 return rt_period_us;
8571 static int sched_rt_global_constraints(void)
8575 mutex_lock(&rt_constraints_mutex);
8576 if (!__rt_schedulable(NULL, 1, 0))
8578 mutex_unlock(&rt_constraints_mutex);
8583 static int sched_rt_global_constraints(void)
8585 unsigned long flags;
8588 spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
8589 for_each_possible_cpu(i) {
8590 struct rt_rq *rt_rq = &cpu_rq(i)->rt;
8592 spin_lock(&rt_rq->rt_runtime_lock);
8593 rt_rq->rt_runtime = global_rt_runtime();
8594 spin_unlock(&rt_rq->rt_runtime_lock);
8596 spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags);
8602 int sched_rt_handler(struct ctl_table *table, int write,
8603 struct file *filp, void __user *buffer, size_t *lenp,
8607 int old_period, old_runtime;
8608 static DEFINE_MUTEX(mutex);
8611 old_period = sysctl_sched_rt_period;
8612 old_runtime = sysctl_sched_rt_runtime;
8614 ret = proc_dointvec(table, write, filp, buffer, lenp, ppos);
8616 if (!ret && write) {
8617 ret = sched_rt_global_constraints();
8619 sysctl_sched_rt_period = old_period;
8620 sysctl_sched_rt_runtime = old_runtime;
8622 def_rt_bandwidth.rt_runtime = global_rt_runtime();
8623 def_rt_bandwidth.rt_period =
8624 ns_to_ktime(global_rt_period());
8627 mutex_unlock(&mutex);
8632 #ifdef CONFIG_CGROUP_SCHED
8634 /* return corresponding task_group object of a cgroup */
8635 static inline struct task_group *cgroup_tg(struct cgroup *cgrp)
8637 return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id),
8638 struct task_group, css);
8641 static struct cgroup_subsys_state *
8642 cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp)
8644 struct task_group *tg, *parent;
8646 if (!cgrp->parent) {
8647 /* This is early initialization for the top cgroup */
8648 init_task_group.css.cgroup = cgrp;
8649 return &init_task_group.css;
8652 parent = cgroup_tg(cgrp->parent);
8653 tg = sched_create_group(parent);
8655 return ERR_PTR(-ENOMEM);
8657 /* Bind the cgroup to task_group object we just created */
8658 tg->css.cgroup = cgrp;
8664 cpu_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
8666 struct task_group *tg = cgroup_tg(cgrp);
8668 sched_destroy_group(tg);
8672 cpu_cgroup_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
8673 struct task_struct *tsk)
8675 #ifdef CONFIG_RT_GROUP_SCHED
8676 /* Don't accept realtime tasks when there is no way for them to run */
8677 if (rt_task(tsk) && cgroup_tg(cgrp)->rt_bandwidth.rt_runtime == 0)
8680 /* We don't support RT-tasks being in separate groups */
8681 if (tsk->sched_class != &fair_sched_class)
8689 cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
8690 struct cgroup *old_cont, struct task_struct *tsk)
8692 sched_move_task(tsk);
8695 #ifdef CONFIG_FAIR_GROUP_SCHED
8696 static int cpu_shares_write_u64(struct cgroup *cgrp, struct cftype *cftype,
8699 return sched_group_set_shares(cgroup_tg(cgrp), shareval);
8702 static u64 cpu_shares_read_u64(struct cgroup *cgrp, struct cftype *cft)
8704 struct task_group *tg = cgroup_tg(cgrp);
8706 return (u64) tg->shares;
8710 #ifdef CONFIG_RT_GROUP_SCHED
8711 static int cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft,
8714 return sched_group_set_rt_runtime(cgroup_tg(cgrp), val);
8717 static s64 cpu_rt_runtime_read(struct cgroup *cgrp, struct cftype *cft)
8719 return sched_group_rt_runtime(cgroup_tg(cgrp));
8722 static int cpu_rt_period_write_uint(struct cgroup *cgrp, struct cftype *cftype,
8725 return sched_group_set_rt_period(cgroup_tg(cgrp), rt_period_us);
8728 static u64 cpu_rt_period_read_uint(struct cgroup *cgrp, struct cftype *cft)
8730 return sched_group_rt_period(cgroup_tg(cgrp));
8734 static struct cftype cpu_files[] = {
8735 #ifdef CONFIG_FAIR_GROUP_SCHED
8738 .read_u64 = cpu_shares_read_u64,
8739 .write_u64 = cpu_shares_write_u64,
8742 #ifdef CONFIG_RT_GROUP_SCHED
8744 .name = "rt_runtime_us",
8745 .read_s64 = cpu_rt_runtime_read,
8746 .write_s64 = cpu_rt_runtime_write,
8749 .name = "rt_period_us",
8750 .read_u64 = cpu_rt_period_read_uint,
8751 .write_u64 = cpu_rt_period_write_uint,
8756 static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont)
8758 return cgroup_add_files(cont, ss, cpu_files, ARRAY_SIZE(cpu_files));
8761 struct cgroup_subsys cpu_cgroup_subsys = {
8763 .create = cpu_cgroup_create,
8764 .destroy = cpu_cgroup_destroy,
8765 .can_attach = cpu_cgroup_can_attach,
8766 .attach = cpu_cgroup_attach,
8767 .populate = cpu_cgroup_populate,
8768 .subsys_id = cpu_cgroup_subsys_id,
8772 #endif /* CONFIG_CGROUP_SCHED */
8774 #ifdef CONFIG_CGROUP_CPUACCT
8777 * CPU accounting code for task groups.
8779 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
8780 * (balbir@in.ibm.com).
8783 /* track cpu usage of a group of tasks */
8785 struct cgroup_subsys_state css;
8786 /* cpuusage holds pointer to a u64-type object on every cpu */
8790 struct cgroup_subsys cpuacct_subsys;
8792 /* return cpu accounting group corresponding to this container */
8793 static inline struct cpuacct *cgroup_ca(struct cgroup *cgrp)
8795 return container_of(cgroup_subsys_state(cgrp, cpuacct_subsys_id),
8796 struct cpuacct, css);
8799 /* return cpu accounting group to which this task belongs */
8800 static inline struct cpuacct *task_ca(struct task_struct *tsk)
8802 return container_of(task_subsys_state(tsk, cpuacct_subsys_id),
8803 struct cpuacct, css);
8806 /* create a new cpu accounting group */
8807 static struct cgroup_subsys_state *cpuacct_create(
8808 struct cgroup_subsys *ss, struct cgroup *cgrp)
8810 struct cpuacct *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
8813 return ERR_PTR(-ENOMEM);
8815 ca->cpuusage = alloc_percpu(u64);
8816 if (!ca->cpuusage) {
8818 return ERR_PTR(-ENOMEM);
8824 /* destroy an existing cpu accounting group */
8826 cpuacct_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
8828 struct cpuacct *ca = cgroup_ca(cgrp);
8830 free_percpu(ca->cpuusage);
8834 /* return total cpu usage (in nanoseconds) of a group */
8835 static u64 cpuusage_read(struct cgroup *cgrp, struct cftype *cft)
8837 struct cpuacct *ca = cgroup_ca(cgrp);
8838 u64 totalcpuusage = 0;
8841 for_each_possible_cpu(i) {
8842 u64 *cpuusage = percpu_ptr(ca->cpuusage, i);
8845 * Take rq->lock to make 64-bit addition safe on 32-bit
8848 spin_lock_irq(&cpu_rq(i)->lock);
8849 totalcpuusage += *cpuusage;
8850 spin_unlock_irq(&cpu_rq(i)->lock);
8853 return totalcpuusage;
8856 static int cpuusage_write(struct cgroup *cgrp, struct cftype *cftype,
8859 struct cpuacct *ca = cgroup_ca(cgrp);
8868 for_each_possible_cpu(i) {
8869 u64 *cpuusage = percpu_ptr(ca->cpuusage, i);
8871 spin_lock_irq(&cpu_rq(i)->lock);
8873 spin_unlock_irq(&cpu_rq(i)->lock);
8879 static struct cftype files[] = {
8882 .read_u64 = cpuusage_read,
8883 .write_u64 = cpuusage_write,
8887 static int cpuacct_populate(struct cgroup_subsys *ss, struct cgroup *cgrp)
8889 return cgroup_add_files(cgrp, ss, files, ARRAY_SIZE(files));
8893 * charge this task's execution time to its accounting group.
8895 * called with rq->lock held.
8897 static void cpuacct_charge(struct task_struct *tsk, u64 cputime)
8901 if (!cpuacct_subsys.active)
8906 u64 *cpuusage = percpu_ptr(ca->cpuusage, task_cpu(tsk));
8908 *cpuusage += cputime;
8912 struct cgroup_subsys cpuacct_subsys = {
8914 .create = cpuacct_create,
8915 .destroy = cpuacct_destroy,
8916 .populate = cpuacct_populate,
8917 .subsys_id = cpuacct_subsys_id,
8919 #endif /* CONFIG_CGROUP_CPUACCT */