4 * Kernel scheduler and related syscalls
6 * Copyright (C) 1991-2002 Linus Torvalds
8 * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and
9 * make semaphores SMP safe
10 * 1998-11-19 Implemented schedule_timeout() and related stuff
12 * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar:
13 * hybrid priority-list and round-robin design with
14 * an array-switch method of distributing timeslices
15 * and per-CPU runqueues. Cleanups and useful suggestions
16 * by Davide Libenzi, preemptible kernel bits by Robert Love.
17 * 2003-09-03 Interactivity tuning by Con Kolivas.
18 * 2004-04-02 Scheduler domains code by Nick Piggin
19 * 2007-04-15 Work begun on replacing all interactivity tuning with a
20 * fair scheduling design by Con Kolivas.
21 * 2007-05-05 Load balancing (smp-nice) and other improvements
23 * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith
24 * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri
25 * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins,
26 * Thomas Gleixner, Mike Kravetz
30 #include <linux/module.h>
31 #include <linux/nmi.h>
32 #include <linux/init.h>
33 #include <linux/uaccess.h>
34 #include <linux/highmem.h>
35 #include <linux/smp_lock.h>
36 #include <asm/mmu_context.h>
37 #include <linux/interrupt.h>
38 #include <linux/capability.h>
39 #include <linux/completion.h>
40 #include <linux/kernel_stat.h>
41 #include <linux/debug_locks.h>
42 #include <linux/perf_event.h>
43 #include <linux/security.h>
44 #include <linux/notifier.h>
45 #include <linux/profile.h>
46 #include <linux/freezer.h>
47 #include <linux/vmalloc.h>
48 #include <linux/blkdev.h>
49 #include <linux/delay.h>
50 #include <linux/pid_namespace.h>
51 #include <linux/smp.h>
52 #include <linux/threads.h>
53 #include <linux/timer.h>
54 #include <linux/rcupdate.h>
55 #include <linux/cpu.h>
56 #include <linux/cpuset.h>
57 #include <linux/percpu.h>
58 #include <linux/proc_fs.h>
59 #include <linux/seq_file.h>
60 #include <linux/stop_machine.h>
61 #include <linux/sysctl.h>
62 #include <linux/syscalls.h>
63 #include <linux/times.h>
64 #include <linux/tsacct_kern.h>
65 #include <linux/kprobes.h>
66 #include <linux/delayacct.h>
67 #include <linux/unistd.h>
68 #include <linux/pagemap.h>
69 #include <linux/hrtimer.h>
70 #include <linux/tick.h>
71 #include <linux/debugfs.h>
72 #include <linux/ctype.h>
73 #include <linux/ftrace.h>
74 #include <linux/slab.h>
77 #include <asm/irq_regs.h>
79 #include "sched_cpupri.h"
80 #include "workqueue_sched.h"
82 #define CREATE_TRACE_POINTS
83 #include <trace/events/sched.h>
86 * Convert user-nice values [ -20 ... 0 ... 19 ]
87 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
90 #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
91 #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
92 #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
95 * 'User priority' is the nice value converted to something we
96 * can work with better when scaling various scheduler parameters,
97 * it's a [ 0 ... 39 ] range.
99 #define USER_PRIO(p) ((p)-MAX_RT_PRIO)
100 #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
101 #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
104 * Helpers for converting nanosecond timing to jiffy resolution
106 #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
108 #define NICE_0_LOAD SCHED_LOAD_SCALE
109 #define NICE_0_SHIFT SCHED_LOAD_SHIFT
112 * These are the 'tuning knobs' of the scheduler:
114 * default timeslice is 100 msecs (used only for SCHED_RR tasks).
115 * Timeslices get refilled after they expire.
117 #define DEF_TIMESLICE (100 * HZ / 1000)
120 * single value that denotes runtime == period, ie unlimited time.
122 #define RUNTIME_INF ((u64)~0ULL)
124 static inline int rt_policy(int policy
)
126 if (unlikely(policy
== SCHED_FIFO
|| policy
== SCHED_RR
))
131 static inline int task_has_rt_policy(struct task_struct
*p
)
133 return rt_policy(p
->policy
);
137 * This is the priority-queue data structure of the RT scheduling class:
139 struct rt_prio_array
{
140 DECLARE_BITMAP(bitmap
, MAX_RT_PRIO
+1); /* include 1 bit for delimiter */
141 struct list_head queue
[MAX_RT_PRIO
];
144 struct rt_bandwidth
{
145 /* nests inside the rq lock: */
146 raw_spinlock_t rt_runtime_lock
;
149 struct hrtimer rt_period_timer
;
152 static struct rt_bandwidth def_rt_bandwidth
;
154 static int do_sched_rt_period_timer(struct rt_bandwidth
*rt_b
, int overrun
);
156 static enum hrtimer_restart
sched_rt_period_timer(struct hrtimer
*timer
)
158 struct rt_bandwidth
*rt_b
=
159 container_of(timer
, struct rt_bandwidth
, rt_period_timer
);
165 now
= hrtimer_cb_get_time(timer
);
166 overrun
= hrtimer_forward(timer
, now
, rt_b
->rt_period
);
171 idle
= do_sched_rt_period_timer(rt_b
, overrun
);
174 return idle
? HRTIMER_NORESTART
: HRTIMER_RESTART
;
178 void init_rt_bandwidth(struct rt_bandwidth
*rt_b
, u64 period
, u64 runtime
)
180 rt_b
->rt_period
= ns_to_ktime(period
);
181 rt_b
->rt_runtime
= runtime
;
183 raw_spin_lock_init(&rt_b
->rt_runtime_lock
);
185 hrtimer_init(&rt_b
->rt_period_timer
,
186 CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
187 rt_b
->rt_period_timer
.function
= sched_rt_period_timer
;
190 static inline int rt_bandwidth_enabled(void)
192 return sysctl_sched_rt_runtime
>= 0;
195 static void start_rt_bandwidth(struct rt_bandwidth
*rt_b
)
199 if (!rt_bandwidth_enabled() || rt_b
->rt_runtime
== RUNTIME_INF
)
202 if (hrtimer_active(&rt_b
->rt_period_timer
))
205 raw_spin_lock(&rt_b
->rt_runtime_lock
);
210 if (hrtimer_active(&rt_b
->rt_period_timer
))
213 now
= hrtimer_cb_get_time(&rt_b
->rt_period_timer
);
214 hrtimer_forward(&rt_b
->rt_period_timer
, now
, rt_b
->rt_period
);
216 soft
= hrtimer_get_softexpires(&rt_b
->rt_period_timer
);
217 hard
= hrtimer_get_expires(&rt_b
->rt_period_timer
);
218 delta
= ktime_to_ns(ktime_sub(hard
, soft
));
219 __hrtimer_start_range_ns(&rt_b
->rt_period_timer
, soft
, delta
,
220 HRTIMER_MODE_ABS_PINNED
, 0);
222 raw_spin_unlock(&rt_b
->rt_runtime_lock
);
225 #ifdef CONFIG_RT_GROUP_SCHED
226 static void destroy_rt_bandwidth(struct rt_bandwidth
*rt_b
)
228 hrtimer_cancel(&rt_b
->rt_period_timer
);
233 * sched_domains_mutex serializes calls to arch_init_sched_domains,
234 * detach_destroy_domains and partition_sched_domains.
236 static DEFINE_MUTEX(sched_domains_mutex
);
238 #ifdef CONFIG_CGROUP_SCHED
240 #include <linux/cgroup.h>
244 static LIST_HEAD(task_groups
);
246 /* task group related information */
248 struct cgroup_subsys_state css
;
250 #ifdef CONFIG_FAIR_GROUP_SCHED
251 /* schedulable entities of this group on each cpu */
252 struct sched_entity
**se
;
253 /* runqueue "owned" by this group on each cpu */
254 struct cfs_rq
**cfs_rq
;
255 unsigned long shares
;
258 #ifdef CONFIG_RT_GROUP_SCHED
259 struct sched_rt_entity
**rt_se
;
260 struct rt_rq
**rt_rq
;
262 struct rt_bandwidth rt_bandwidth
;
266 struct list_head list
;
268 struct task_group
*parent
;
269 struct list_head siblings
;
270 struct list_head children
;
273 #define root_task_group init_task_group
275 /* task_group_lock serializes add/remove of task groups and also changes to
276 * a task group's cpu shares.
278 static DEFINE_SPINLOCK(task_group_lock
);
280 #ifdef CONFIG_FAIR_GROUP_SCHED
283 static int root_task_group_empty(void)
285 return list_empty(&root_task_group
.children
);
289 # define INIT_TASK_GROUP_LOAD NICE_0_LOAD
292 * A weight of 0 or 1 can cause arithmetics problems.
293 * A weight of a cfs_rq is the sum of weights of which entities
294 * are queued on this cfs_rq, so a weight of a entity should not be
295 * too large, so as the shares value of a task group.
296 * (The default weight is 1024 - so there's no practical
297 * limitation from this.)
300 #define MAX_SHARES (1UL << 18)
302 static int init_task_group_load
= INIT_TASK_GROUP_LOAD
;
305 /* Default task group.
306 * Every task in system belong to this group at bootup.
308 struct task_group init_task_group
;
310 #endif /* CONFIG_CGROUP_SCHED */
312 /* CFS-related fields in a runqueue */
314 struct load_weight load
;
315 unsigned long nr_running
;
320 struct rb_root tasks_timeline
;
321 struct rb_node
*rb_leftmost
;
323 struct list_head tasks
;
324 struct list_head
*balance_iterator
;
327 * 'curr' points to currently running entity on this cfs_rq.
328 * It is set to NULL otherwise (i.e when none are currently running).
330 struct sched_entity
*curr
, *next
, *last
;
332 unsigned int nr_spread_over
;
334 #ifdef CONFIG_FAIR_GROUP_SCHED
335 struct rq
*rq
; /* cpu runqueue to which this cfs_rq is attached */
338 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
339 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
340 * (like users, containers etc.)
342 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
343 * list is used during load balance.
345 struct list_head leaf_cfs_rq_list
;
346 struct task_group
*tg
; /* group that "owns" this runqueue */
350 * the part of load.weight contributed by tasks
352 unsigned long task_weight
;
355 * h_load = weight * f(tg)
357 * Where f(tg) is the recursive weight fraction assigned to
360 unsigned long h_load
;
363 * this cpu's part of tg->shares
365 unsigned long shares
;
368 * load.weight at the time we set shares
370 unsigned long rq_weight
;
375 /* Real-Time classes' related field in a runqueue: */
377 struct rt_prio_array active
;
378 unsigned long rt_nr_running
;
379 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
381 int curr
; /* highest queued rt task prio */
383 int next
; /* next highest */
388 unsigned long rt_nr_migratory
;
389 unsigned long rt_nr_total
;
391 struct plist_head pushable_tasks
;
396 /* Nests inside the rq lock: */
397 raw_spinlock_t rt_runtime_lock
;
399 #ifdef CONFIG_RT_GROUP_SCHED
400 unsigned long rt_nr_boosted
;
403 struct list_head leaf_rt_rq_list
;
404 struct task_group
*tg
;
411 * We add the notion of a root-domain which will be used to define per-domain
412 * variables. Each exclusive cpuset essentially defines an island domain by
413 * fully partitioning the member cpus from any other cpuset. Whenever a new
414 * exclusive cpuset is created, we also create and attach a new root-domain
421 cpumask_var_t online
;
424 * The "RT overload" flag: it gets set if a CPU has more than
425 * one runnable RT task.
427 cpumask_var_t rto_mask
;
430 struct cpupri cpupri
;
435 * By default the system creates a single root-domain with all cpus as
436 * members (mimicking the global state we have today).
438 static struct root_domain def_root_domain
;
443 * This is the main, per-CPU runqueue data structure.
445 * Locking rule: those places that want to lock multiple runqueues
446 * (such as the load balancing or the thread migration code), lock
447 * acquire operations must be ordered by ascending &runqueue.
454 * nr_running and cpu_load should be in the same cacheline because
455 * remote CPUs use both these fields when doing load calculation.
457 unsigned long nr_running
;
458 #define CPU_LOAD_IDX_MAX 5
459 unsigned long cpu_load
[CPU_LOAD_IDX_MAX
];
460 unsigned long last_load_update_tick
;
463 unsigned char nohz_balance_kick
;
465 unsigned int skip_clock_update
;
467 /* capture load from *all* tasks on this cpu: */
468 struct load_weight load
;
469 unsigned long nr_load_updates
;
475 #ifdef CONFIG_FAIR_GROUP_SCHED
476 /* list of leaf cfs_rq on this cpu: */
477 struct list_head leaf_cfs_rq_list
;
479 #ifdef CONFIG_RT_GROUP_SCHED
480 struct list_head leaf_rt_rq_list
;
484 * This is part of a global counter where only the total sum
485 * over all CPUs matters. A task can increase this counter on
486 * one CPU and if it got migrated afterwards it may decrease
487 * it on another CPU. Always updated under the runqueue lock:
489 unsigned long nr_uninterruptible
;
491 struct task_struct
*curr
, *idle
;
492 unsigned long next_balance
;
493 struct mm_struct
*prev_mm
;
500 struct root_domain
*rd
;
501 struct sched_domain
*sd
;
503 unsigned long cpu_power
;
505 unsigned char idle_at_tick
;
506 /* For active balancing */
510 struct cpu_stop_work active_balance_work
;
511 /* cpu of this runqueue: */
515 unsigned long avg_load_per_task
;
523 /* calc_load related fields */
524 unsigned long calc_load_update
;
525 long calc_load_active
;
527 #ifdef CONFIG_SCHED_HRTICK
529 int hrtick_csd_pending
;
530 struct call_single_data hrtick_csd
;
532 struct hrtimer hrtick_timer
;
535 #ifdef CONFIG_SCHEDSTATS
537 struct sched_info rq_sched_info
;
538 unsigned long long rq_cpu_time
;
539 /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
541 /* sys_sched_yield() stats */
542 unsigned int yld_count
;
544 /* schedule() stats */
545 unsigned int sched_switch
;
546 unsigned int sched_count
;
547 unsigned int sched_goidle
;
549 /* try_to_wake_up() stats */
550 unsigned int ttwu_count
;
551 unsigned int ttwu_local
;
554 unsigned int bkl_count
;
558 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
561 void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int flags
)
563 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
, flags
);
566 * A queue event has occurred, and we're going to schedule. In
567 * this case, we can save a useless back to back clock update.
569 if (test_tsk_need_resched(p
))
570 rq
->skip_clock_update
= 1;
573 static inline int cpu_of(struct rq
*rq
)
582 #define rcu_dereference_check_sched_domain(p) \
583 rcu_dereference_check((p), \
584 rcu_read_lock_sched_held() || \
585 lockdep_is_held(&sched_domains_mutex))
588 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
589 * See detach_destroy_domains: synchronize_sched for details.
591 * The domain tree of any CPU may only be accessed from within
592 * preempt-disabled sections.
594 #define for_each_domain(cpu, __sd) \
595 for (__sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
597 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
598 #define this_rq() (&__get_cpu_var(runqueues))
599 #define task_rq(p) cpu_rq(task_cpu(p))
600 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
601 #define raw_rq() (&__raw_get_cpu_var(runqueues))
603 #ifdef CONFIG_CGROUP_SCHED
606 * Return the group to which this tasks belongs.
608 * We use task_subsys_state_check() and extend the RCU verification
609 * with lockdep_is_held(&task_rq(p)->lock) because cpu_cgroup_attach()
610 * holds that lock for each task it moves into the cgroup. Therefore
611 * by holding that lock, we pin the task to the current cgroup.
613 static inline struct task_group
*task_group(struct task_struct
*p
)
615 struct cgroup_subsys_state
*css
;
617 css
= task_subsys_state_check(p
, cpu_cgroup_subsys_id
,
618 lockdep_is_held(&task_rq(p
)->lock
));
619 return container_of(css
, struct task_group
, css
);
622 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
623 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
)
625 #ifdef CONFIG_FAIR_GROUP_SCHED
626 p
->se
.cfs_rq
= task_group(p
)->cfs_rq
[cpu
];
627 p
->se
.parent
= task_group(p
)->se
[cpu
];
630 #ifdef CONFIG_RT_GROUP_SCHED
631 p
->rt
.rt_rq
= task_group(p
)->rt_rq
[cpu
];
632 p
->rt
.parent
= task_group(p
)->rt_se
[cpu
];
636 #else /* CONFIG_CGROUP_SCHED */
638 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
) { }
639 static inline struct task_group
*task_group(struct task_struct
*p
)
644 #endif /* CONFIG_CGROUP_SCHED */
646 inline void update_rq_clock(struct rq
*rq
)
648 if (!rq
->skip_clock_update
)
649 rq
->clock
= sched_clock_cpu(cpu_of(rq
));
653 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
655 #ifdef CONFIG_SCHED_DEBUG
656 # define const_debug __read_mostly
658 # define const_debug static const
663 * @cpu: the processor in question.
665 * Returns true if the current cpu runqueue is locked.
666 * This interface allows printk to be called with the runqueue lock
667 * held and know whether or not it is OK to wake up the klogd.
669 int runqueue_is_locked(int cpu
)
671 return raw_spin_is_locked(&cpu_rq(cpu
)->lock
);
675 * Debugging: various feature bits
678 #define SCHED_FEAT(name, enabled) \
679 __SCHED_FEAT_##name ,
682 #include "sched_features.h"
687 #define SCHED_FEAT(name, enabled) \
688 (1UL << __SCHED_FEAT_##name) * enabled |
690 const_debug
unsigned int sysctl_sched_features
=
691 #include "sched_features.h"
696 #ifdef CONFIG_SCHED_DEBUG
697 #define SCHED_FEAT(name, enabled) \
700 static __read_mostly
char *sched_feat_names
[] = {
701 #include "sched_features.h"
707 static int sched_feat_show(struct seq_file
*m
, void *v
)
711 for (i
= 0; sched_feat_names
[i
]; i
++) {
712 if (!(sysctl_sched_features
& (1UL << i
)))
714 seq_printf(m
, "%s ", sched_feat_names
[i
]);
722 sched_feat_write(struct file
*filp
, const char __user
*ubuf
,
723 size_t cnt
, loff_t
*ppos
)
733 if (copy_from_user(&buf
, ubuf
, cnt
))
738 if (strncmp(buf
, "NO_", 3) == 0) {
743 for (i
= 0; sched_feat_names
[i
]; i
++) {
744 int len
= strlen(sched_feat_names
[i
]);
746 if (strncmp(cmp
, sched_feat_names
[i
], len
) == 0) {
748 sysctl_sched_features
&= ~(1UL << i
);
750 sysctl_sched_features
|= (1UL << i
);
755 if (!sched_feat_names
[i
])
763 static int sched_feat_open(struct inode
*inode
, struct file
*filp
)
765 return single_open(filp
, sched_feat_show
, NULL
);
768 static const struct file_operations sched_feat_fops
= {
769 .open
= sched_feat_open
,
770 .write
= sched_feat_write
,
773 .release
= single_release
,
776 static __init
int sched_init_debug(void)
778 debugfs_create_file("sched_features", 0644, NULL
, NULL
,
783 late_initcall(sched_init_debug
);
787 #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
790 * Number of tasks to iterate in a single balance run.
791 * Limited because this is done with IRQs disabled.
793 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
796 * ratelimit for updating the group shares.
799 unsigned int sysctl_sched_shares_ratelimit
= 250000;
800 unsigned int normalized_sysctl_sched_shares_ratelimit
= 250000;
803 * Inject some fuzzyness into changing the per-cpu group shares
804 * this avoids remote rq-locks at the expense of fairness.
807 unsigned int sysctl_sched_shares_thresh
= 4;
810 * period over which we average the RT time consumption, measured
815 const_debug
unsigned int sysctl_sched_time_avg
= MSEC_PER_SEC
;
818 * period over which we measure -rt task cpu usage in us.
821 unsigned int sysctl_sched_rt_period
= 1000000;
823 static __read_mostly
int scheduler_running
;
826 * part of the period that we allow rt tasks to run in us.
829 int sysctl_sched_rt_runtime
= 950000;
831 static inline u64
global_rt_period(void)
833 return (u64
)sysctl_sched_rt_period
* NSEC_PER_USEC
;
836 static inline u64
global_rt_runtime(void)
838 if (sysctl_sched_rt_runtime
< 0)
841 return (u64
)sysctl_sched_rt_runtime
* NSEC_PER_USEC
;
844 #ifndef prepare_arch_switch
845 # define prepare_arch_switch(next) do { } while (0)
847 #ifndef finish_arch_switch
848 # define finish_arch_switch(prev) do { } while (0)
851 static inline int task_current(struct rq
*rq
, struct task_struct
*p
)
853 return rq
->curr
== p
;
856 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
857 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
859 return task_current(rq
, p
);
862 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
866 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
868 #ifdef CONFIG_DEBUG_SPINLOCK
869 /* this is a valid case when another task releases the spinlock */
870 rq
->lock
.owner
= current
;
873 * If we are tracking spinlock dependencies then we have to
874 * fix up the runqueue lock - which gets 'carried over' from
877 spin_acquire(&rq
->lock
.dep_map
, 0, 0, _THIS_IP_
);
879 raw_spin_unlock_irq(&rq
->lock
);
882 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
883 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
888 return task_current(rq
, p
);
892 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
896 * We can optimise this out completely for !SMP, because the
897 * SMP rebalancing from interrupt is the only thing that cares
902 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
903 raw_spin_unlock_irq(&rq
->lock
);
905 raw_spin_unlock(&rq
->lock
);
909 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
913 * After ->oncpu is cleared, the task can be moved to a different CPU.
914 * We must ensure this doesn't happen until the switch is completely
920 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
924 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
927 * Check whether the task is waking, we use this to synchronize ->cpus_allowed
930 static inline int task_is_waking(struct task_struct
*p
)
932 return unlikely(p
->state
== TASK_WAKING
);
936 * __task_rq_lock - lock the runqueue a given task resides on.
937 * Must be called interrupts disabled.
939 static inline struct rq
*__task_rq_lock(struct task_struct
*p
)
946 raw_spin_lock(&rq
->lock
);
947 if (likely(rq
== task_rq(p
)))
949 raw_spin_unlock(&rq
->lock
);
954 * task_rq_lock - lock the runqueue a given task resides on and disable
955 * interrupts. Note the ordering: we can safely lookup the task_rq without
956 * explicitly disabling preemption.
958 static struct rq
*task_rq_lock(struct task_struct
*p
, unsigned long *flags
)
964 local_irq_save(*flags
);
966 raw_spin_lock(&rq
->lock
);
967 if (likely(rq
== task_rq(p
)))
969 raw_spin_unlock_irqrestore(&rq
->lock
, *flags
);
973 static void __task_rq_unlock(struct rq
*rq
)
976 raw_spin_unlock(&rq
->lock
);
979 static inline void task_rq_unlock(struct rq
*rq
, unsigned long *flags
)
982 raw_spin_unlock_irqrestore(&rq
->lock
, *flags
);
986 * this_rq_lock - lock this runqueue and disable interrupts.
988 static struct rq
*this_rq_lock(void)
995 raw_spin_lock(&rq
->lock
);
1000 #ifdef CONFIG_SCHED_HRTICK
1002 * Use HR-timers to deliver accurate preemption points.
1004 * Its all a bit involved since we cannot program an hrt while holding the
1005 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
1008 * When we get rescheduled we reprogram the hrtick_timer outside of the
1014 * - enabled by features
1015 * - hrtimer is actually high res
1017 static inline int hrtick_enabled(struct rq
*rq
)
1019 if (!sched_feat(HRTICK
))
1021 if (!cpu_active(cpu_of(rq
)))
1023 return hrtimer_is_hres_active(&rq
->hrtick_timer
);
1026 static void hrtick_clear(struct rq
*rq
)
1028 if (hrtimer_active(&rq
->hrtick_timer
))
1029 hrtimer_cancel(&rq
->hrtick_timer
);
1033 * High-resolution timer tick.
1034 * Runs from hardirq context with interrupts disabled.
1036 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
1038 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
1040 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1042 raw_spin_lock(&rq
->lock
);
1043 update_rq_clock(rq
);
1044 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
1045 raw_spin_unlock(&rq
->lock
);
1047 return HRTIMER_NORESTART
;
1052 * called from hardirq (IPI) context
1054 static void __hrtick_start(void *arg
)
1056 struct rq
*rq
= arg
;
1058 raw_spin_lock(&rq
->lock
);
1059 hrtimer_restart(&rq
->hrtick_timer
);
1060 rq
->hrtick_csd_pending
= 0;
1061 raw_spin_unlock(&rq
->lock
);
1065 * Called to set the hrtick timer state.
1067 * called with rq->lock held and irqs disabled
1069 static void hrtick_start(struct rq
*rq
, u64 delay
)
1071 struct hrtimer
*timer
= &rq
->hrtick_timer
;
1072 ktime_t time
= ktime_add_ns(timer
->base
->get_time(), delay
);
1074 hrtimer_set_expires(timer
, time
);
1076 if (rq
== this_rq()) {
1077 hrtimer_restart(timer
);
1078 } else if (!rq
->hrtick_csd_pending
) {
1079 __smp_call_function_single(cpu_of(rq
), &rq
->hrtick_csd
, 0);
1080 rq
->hrtick_csd_pending
= 1;
1085 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
1087 int cpu
= (int)(long)hcpu
;
1090 case CPU_UP_CANCELED
:
1091 case CPU_UP_CANCELED_FROZEN
:
1092 case CPU_DOWN_PREPARE
:
1093 case CPU_DOWN_PREPARE_FROZEN
:
1095 case CPU_DEAD_FROZEN
:
1096 hrtick_clear(cpu_rq(cpu
));
1103 static __init
void init_hrtick(void)
1105 hotcpu_notifier(hotplug_hrtick
, 0);
1109 * Called to set the hrtick timer state.
1111 * called with rq->lock held and irqs disabled
1113 static void hrtick_start(struct rq
*rq
, u64 delay
)
1115 __hrtimer_start_range_ns(&rq
->hrtick_timer
, ns_to_ktime(delay
), 0,
1116 HRTIMER_MODE_REL_PINNED
, 0);
1119 static inline void init_hrtick(void)
1122 #endif /* CONFIG_SMP */
1124 static void init_rq_hrtick(struct rq
*rq
)
1127 rq
->hrtick_csd_pending
= 0;
1129 rq
->hrtick_csd
.flags
= 0;
1130 rq
->hrtick_csd
.func
= __hrtick_start
;
1131 rq
->hrtick_csd
.info
= rq
;
1134 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1135 rq
->hrtick_timer
.function
= hrtick
;
1137 #else /* CONFIG_SCHED_HRTICK */
1138 static inline void hrtick_clear(struct rq
*rq
)
1142 static inline void init_rq_hrtick(struct rq
*rq
)
1146 static inline void init_hrtick(void)
1149 #endif /* CONFIG_SCHED_HRTICK */
1152 * resched_task - mark a task 'to be rescheduled now'.
1154 * On UP this means the setting of the need_resched flag, on SMP it
1155 * might also involve a cross-CPU call to trigger the scheduler on
1160 #ifndef tsk_is_polling
1161 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1164 static void resched_task(struct task_struct
*p
)
1168 assert_raw_spin_locked(&task_rq(p
)->lock
);
1170 if (test_tsk_need_resched(p
))
1173 set_tsk_need_resched(p
);
1176 if (cpu
== smp_processor_id())
1179 /* NEED_RESCHED must be visible before we test polling */
1181 if (!tsk_is_polling(p
))
1182 smp_send_reschedule(cpu
);
1185 static void resched_cpu(int cpu
)
1187 struct rq
*rq
= cpu_rq(cpu
);
1188 unsigned long flags
;
1190 if (!raw_spin_trylock_irqsave(&rq
->lock
, flags
))
1192 resched_task(cpu_curr(cpu
));
1193 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
1198 * In the semi idle case, use the nearest busy cpu for migrating timers
1199 * from an idle cpu. This is good for power-savings.
1201 * We don't do similar optimization for completely idle system, as
1202 * selecting an idle cpu will add more delays to the timers than intended
1203 * (as that cpu's timer base may not be uptodate wrt jiffies etc).
1205 int get_nohz_timer_target(void)
1207 int cpu
= smp_processor_id();
1209 struct sched_domain
*sd
;
1211 for_each_domain(cpu
, sd
) {
1212 for_each_cpu(i
, sched_domain_span(sd
))
1219 * When add_timer_on() enqueues a timer into the timer wheel of an
1220 * idle CPU then this timer might expire before the next timer event
1221 * which is scheduled to wake up that CPU. In case of a completely
1222 * idle system the next event might even be infinite time into the
1223 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1224 * leaves the inner idle loop so the newly added timer is taken into
1225 * account when the CPU goes back to idle and evaluates the timer
1226 * wheel for the next timer event.
1228 void wake_up_idle_cpu(int cpu
)
1230 struct rq
*rq
= cpu_rq(cpu
);
1232 if (cpu
== smp_processor_id())
1236 * This is safe, as this function is called with the timer
1237 * wheel base lock of (cpu) held. When the CPU is on the way
1238 * to idle and has not yet set rq->curr to idle then it will
1239 * be serialized on the timer wheel base lock and take the new
1240 * timer into account automatically.
1242 if (rq
->curr
!= rq
->idle
)
1246 * We can set TIF_RESCHED on the idle task of the other CPU
1247 * lockless. The worst case is that the other CPU runs the
1248 * idle task through an additional NOOP schedule()
1250 set_tsk_need_resched(rq
->idle
);
1252 /* NEED_RESCHED must be visible before we test polling */
1254 if (!tsk_is_polling(rq
->idle
))
1255 smp_send_reschedule(cpu
);
1258 int nohz_ratelimit(int cpu
)
1260 struct rq
*rq
= cpu_rq(cpu
);
1261 u64 diff
= rq
->clock
- rq
->nohz_stamp
;
1263 rq
->nohz_stamp
= rq
->clock
;
1265 return diff
< (NSEC_PER_SEC
/ HZ
) >> 1;
1268 #endif /* CONFIG_NO_HZ */
1270 static u64
sched_avg_period(void)
1272 return (u64
)sysctl_sched_time_avg
* NSEC_PER_MSEC
/ 2;
1275 static void sched_avg_update(struct rq
*rq
)
1277 s64 period
= sched_avg_period();
1279 while ((s64
)(rq
->clock
- rq
->age_stamp
) > period
) {
1280 rq
->age_stamp
+= period
;
1285 static void sched_rt_avg_update(struct rq
*rq
, u64 rt_delta
)
1287 rq
->rt_avg
+= rt_delta
;
1288 sched_avg_update(rq
);
1291 #else /* !CONFIG_SMP */
1292 static void resched_task(struct task_struct
*p
)
1294 assert_raw_spin_locked(&task_rq(p
)->lock
);
1295 set_tsk_need_resched(p
);
1298 static void sched_rt_avg_update(struct rq
*rq
, u64 rt_delta
)
1301 #endif /* CONFIG_SMP */
1303 #if BITS_PER_LONG == 32
1304 # define WMULT_CONST (~0UL)
1306 # define WMULT_CONST (1UL << 32)
1309 #define WMULT_SHIFT 32
1312 * Shift right and round:
1314 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1317 * delta *= weight / lw
1319 static unsigned long
1320 calc_delta_mine(unsigned long delta_exec
, unsigned long weight
,
1321 struct load_weight
*lw
)
1325 if (!lw
->inv_weight
) {
1326 if (BITS_PER_LONG
> 32 && unlikely(lw
->weight
>= WMULT_CONST
))
1329 lw
->inv_weight
= 1 + (WMULT_CONST
-lw
->weight
/2)
1333 tmp
= (u64
)delta_exec
* weight
;
1335 * Check whether we'd overflow the 64-bit multiplication:
1337 if (unlikely(tmp
> WMULT_CONST
))
1338 tmp
= SRR(SRR(tmp
, WMULT_SHIFT
/2) * lw
->inv_weight
,
1341 tmp
= SRR(tmp
* lw
->inv_weight
, WMULT_SHIFT
);
1343 return (unsigned long)min(tmp
, (u64
)(unsigned long)LONG_MAX
);
1346 static inline void update_load_add(struct load_weight
*lw
, unsigned long inc
)
1352 static inline void update_load_sub(struct load_weight
*lw
, unsigned long dec
)
1359 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1360 * of tasks with abnormal "nice" values across CPUs the contribution that
1361 * each task makes to its run queue's load is weighted according to its
1362 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1363 * scaled version of the new time slice allocation that they receive on time
1367 #define WEIGHT_IDLEPRIO 3
1368 #define WMULT_IDLEPRIO 1431655765
1371 * Nice levels are multiplicative, with a gentle 10% change for every
1372 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1373 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1374 * that remained on nice 0.
1376 * The "10% effect" is relative and cumulative: from _any_ nice level,
1377 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1378 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1379 * If a task goes up by ~10% and another task goes down by ~10% then
1380 * the relative distance between them is ~25%.)
1382 static const int prio_to_weight
[40] = {
1383 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1384 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1385 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1386 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1387 /* 0 */ 1024, 820, 655, 526, 423,
1388 /* 5 */ 335, 272, 215, 172, 137,
1389 /* 10 */ 110, 87, 70, 56, 45,
1390 /* 15 */ 36, 29, 23, 18, 15,
1394 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1396 * In cases where the weight does not change often, we can use the
1397 * precalculated inverse to speed up arithmetics by turning divisions
1398 * into multiplications:
1400 static const u32 prio_to_wmult
[40] = {
1401 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1402 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1403 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1404 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1405 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1406 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1407 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1408 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1411 /* Time spent by the tasks of the cpu accounting group executing in ... */
1412 enum cpuacct_stat_index
{
1413 CPUACCT_STAT_USER
, /* ... user mode */
1414 CPUACCT_STAT_SYSTEM
, /* ... kernel mode */
1416 CPUACCT_STAT_NSTATS
,
1419 #ifdef CONFIG_CGROUP_CPUACCT
1420 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
);
1421 static void cpuacct_update_stats(struct task_struct
*tsk
,
1422 enum cpuacct_stat_index idx
, cputime_t val
);
1424 static inline void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
) {}
1425 static inline void cpuacct_update_stats(struct task_struct
*tsk
,
1426 enum cpuacct_stat_index idx
, cputime_t val
) {}
1429 static inline void inc_cpu_load(struct rq
*rq
, unsigned long load
)
1431 update_load_add(&rq
->load
, load
);
1434 static inline void dec_cpu_load(struct rq
*rq
, unsigned long load
)
1436 update_load_sub(&rq
->load
, load
);
1439 #if (defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)) || defined(CONFIG_RT_GROUP_SCHED)
1440 typedef int (*tg_visitor
)(struct task_group
*, void *);
1443 * Iterate the full tree, calling @down when first entering a node and @up when
1444 * leaving it for the final time.
1446 static int walk_tg_tree(tg_visitor down
, tg_visitor up
, void *data
)
1448 struct task_group
*parent
, *child
;
1452 parent
= &root_task_group
;
1454 ret
= (*down
)(parent
, data
);
1457 list_for_each_entry_rcu(child
, &parent
->children
, siblings
) {
1464 ret
= (*up
)(parent
, data
);
1469 parent
= parent
->parent
;
1478 static int tg_nop(struct task_group
*tg
, void *data
)
1485 /* Used instead of source_load when we know the type == 0 */
1486 static unsigned long weighted_cpuload(const int cpu
)
1488 return cpu_rq(cpu
)->load
.weight
;
1492 * Return a low guess at the load of a migration-source cpu weighted
1493 * according to the scheduling class and "nice" value.
1495 * We want to under-estimate the load of migration sources, to
1496 * balance conservatively.
1498 static unsigned long source_load(int cpu
, int type
)
1500 struct rq
*rq
= cpu_rq(cpu
);
1501 unsigned long total
= weighted_cpuload(cpu
);
1503 if (type
== 0 || !sched_feat(LB_BIAS
))
1506 return min(rq
->cpu_load
[type
-1], total
);
1510 * Return a high guess at the load of a migration-target cpu weighted
1511 * according to the scheduling class and "nice" value.
1513 static unsigned long target_load(int cpu
, int type
)
1515 struct rq
*rq
= cpu_rq(cpu
);
1516 unsigned long total
= weighted_cpuload(cpu
);
1518 if (type
== 0 || !sched_feat(LB_BIAS
))
1521 return max(rq
->cpu_load
[type
-1], total
);
1524 static unsigned long power_of(int cpu
)
1526 return cpu_rq(cpu
)->cpu_power
;
1529 static int task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
);
1531 static unsigned long cpu_avg_load_per_task(int cpu
)
1533 struct rq
*rq
= cpu_rq(cpu
);
1534 unsigned long nr_running
= ACCESS_ONCE(rq
->nr_running
);
1537 rq
->avg_load_per_task
= rq
->load
.weight
/ nr_running
;
1539 rq
->avg_load_per_task
= 0;
1541 return rq
->avg_load_per_task
;
1544 #ifdef CONFIG_FAIR_GROUP_SCHED
1546 static __read_mostly
unsigned long __percpu
*update_shares_data
;
1548 static void __set_se_shares(struct sched_entity
*se
, unsigned long shares
);
1551 * Calculate and set the cpu's group shares.
1553 static void update_group_shares_cpu(struct task_group
*tg
, int cpu
,
1554 unsigned long sd_shares
,
1555 unsigned long sd_rq_weight
,
1556 unsigned long *usd_rq_weight
)
1558 unsigned long shares
, rq_weight
;
1561 rq_weight
= usd_rq_weight
[cpu
];
1564 rq_weight
= NICE_0_LOAD
;
1568 * \Sum_j shares_j * rq_weight_i
1569 * shares_i = -----------------------------
1570 * \Sum_j rq_weight_j
1572 shares
= (sd_shares
* rq_weight
) / sd_rq_weight
;
1573 shares
= clamp_t(unsigned long, shares
, MIN_SHARES
, MAX_SHARES
);
1575 if (abs(shares
- tg
->se
[cpu
]->load
.weight
) >
1576 sysctl_sched_shares_thresh
) {
1577 struct rq
*rq
= cpu_rq(cpu
);
1578 unsigned long flags
;
1580 raw_spin_lock_irqsave(&rq
->lock
, flags
);
1581 tg
->cfs_rq
[cpu
]->rq_weight
= boost
? 0 : rq_weight
;
1582 tg
->cfs_rq
[cpu
]->shares
= boost
? 0 : shares
;
1583 __set_se_shares(tg
->se
[cpu
], shares
);
1584 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
1589 * Re-compute the task group their per cpu shares over the given domain.
1590 * This needs to be done in a bottom-up fashion because the rq weight of a
1591 * parent group depends on the shares of its child groups.
1593 static int tg_shares_up(struct task_group
*tg
, void *data
)
1595 unsigned long weight
, rq_weight
= 0, sum_weight
= 0, shares
= 0;
1596 unsigned long *usd_rq_weight
;
1597 struct sched_domain
*sd
= data
;
1598 unsigned long flags
;
1604 local_irq_save(flags
);
1605 usd_rq_weight
= per_cpu_ptr(update_shares_data
, smp_processor_id());
1607 for_each_cpu(i
, sched_domain_span(sd
)) {
1608 weight
= tg
->cfs_rq
[i
]->load
.weight
;
1609 usd_rq_weight
[i
] = weight
;
1611 rq_weight
+= weight
;
1613 * If there are currently no tasks on the cpu pretend there
1614 * is one of average load so that when a new task gets to
1615 * run here it will not get delayed by group starvation.
1618 weight
= NICE_0_LOAD
;
1620 sum_weight
+= weight
;
1621 shares
+= tg
->cfs_rq
[i
]->shares
;
1625 rq_weight
= sum_weight
;
1627 if ((!shares
&& rq_weight
) || shares
> tg
->shares
)
1628 shares
= tg
->shares
;
1630 if (!sd
->parent
|| !(sd
->parent
->flags
& SD_LOAD_BALANCE
))
1631 shares
= tg
->shares
;
1633 for_each_cpu(i
, sched_domain_span(sd
))
1634 update_group_shares_cpu(tg
, i
, shares
, rq_weight
, usd_rq_weight
);
1636 local_irq_restore(flags
);
1642 * Compute the cpu's hierarchical load factor for each task group.
1643 * This needs to be done in a top-down fashion because the load of a child
1644 * group is a fraction of its parents load.
1646 static int tg_load_down(struct task_group
*tg
, void *data
)
1649 long cpu
= (long)data
;
1652 load
= cpu_rq(cpu
)->load
.weight
;
1654 load
= tg
->parent
->cfs_rq
[cpu
]->h_load
;
1655 load
*= tg
->cfs_rq
[cpu
]->shares
;
1656 load
/= tg
->parent
->cfs_rq
[cpu
]->load
.weight
+ 1;
1659 tg
->cfs_rq
[cpu
]->h_load
= load
;
1664 static void update_shares(struct sched_domain
*sd
)
1669 if (root_task_group_empty())
1672 now
= local_clock();
1673 elapsed
= now
- sd
->last_update
;
1675 if (elapsed
>= (s64
)(u64
)sysctl_sched_shares_ratelimit
) {
1676 sd
->last_update
= now
;
1677 walk_tg_tree(tg_nop
, tg_shares_up
, sd
);
1681 static void update_h_load(long cpu
)
1683 if (root_task_group_empty())
1686 walk_tg_tree(tg_load_down
, tg_nop
, (void *)cpu
);
1691 static inline void update_shares(struct sched_domain
*sd
)
1697 #ifdef CONFIG_PREEMPT
1699 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
);
1702 * fair double_lock_balance: Safely acquires both rq->locks in a fair
1703 * way at the expense of forcing extra atomic operations in all
1704 * invocations. This assures that the double_lock is acquired using the
1705 * same underlying policy as the spinlock_t on this architecture, which
1706 * reduces latency compared to the unfair variant below. However, it
1707 * also adds more overhead and therefore may reduce throughput.
1709 static inline int _double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1710 __releases(this_rq
->lock
)
1711 __acquires(busiest
->lock
)
1712 __acquires(this_rq
->lock
)
1714 raw_spin_unlock(&this_rq
->lock
);
1715 double_rq_lock(this_rq
, busiest
);
1722 * Unfair double_lock_balance: Optimizes throughput at the expense of
1723 * latency by eliminating extra atomic operations when the locks are
1724 * already in proper order on entry. This favors lower cpu-ids and will
1725 * grant the double lock to lower cpus over higher ids under contention,
1726 * regardless of entry order into the function.
1728 static int _double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1729 __releases(this_rq
->lock
)
1730 __acquires(busiest
->lock
)
1731 __acquires(this_rq
->lock
)
1735 if (unlikely(!raw_spin_trylock(&busiest
->lock
))) {
1736 if (busiest
< this_rq
) {
1737 raw_spin_unlock(&this_rq
->lock
);
1738 raw_spin_lock(&busiest
->lock
);
1739 raw_spin_lock_nested(&this_rq
->lock
,
1740 SINGLE_DEPTH_NESTING
);
1743 raw_spin_lock_nested(&busiest
->lock
,
1744 SINGLE_DEPTH_NESTING
);
1749 #endif /* CONFIG_PREEMPT */
1752 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
1754 static int double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1756 if (unlikely(!irqs_disabled())) {
1757 /* printk() doesn't work good under rq->lock */
1758 raw_spin_unlock(&this_rq
->lock
);
1762 return _double_lock_balance(this_rq
, busiest
);
1765 static inline void double_unlock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1766 __releases(busiest
->lock
)
1768 raw_spin_unlock(&busiest
->lock
);
1769 lock_set_subclass(&this_rq
->lock
.dep_map
, 0, _RET_IP_
);
1773 * double_rq_lock - safely lock two runqueues
1775 * Note this does not disable interrupts like task_rq_lock,
1776 * you need to do so manually before calling.
1778 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
)
1779 __acquires(rq1
->lock
)
1780 __acquires(rq2
->lock
)
1782 BUG_ON(!irqs_disabled());
1784 raw_spin_lock(&rq1
->lock
);
1785 __acquire(rq2
->lock
); /* Fake it out ;) */
1788 raw_spin_lock(&rq1
->lock
);
1789 raw_spin_lock_nested(&rq2
->lock
, SINGLE_DEPTH_NESTING
);
1791 raw_spin_lock(&rq2
->lock
);
1792 raw_spin_lock_nested(&rq1
->lock
, SINGLE_DEPTH_NESTING
);
1798 * double_rq_unlock - safely unlock two runqueues
1800 * Note this does not restore interrupts like task_rq_unlock,
1801 * you need to do so manually after calling.
1803 static void double_rq_unlock(struct rq
*rq1
, struct rq
*rq2
)
1804 __releases(rq1
->lock
)
1805 __releases(rq2
->lock
)
1807 raw_spin_unlock(&rq1
->lock
);
1809 raw_spin_unlock(&rq2
->lock
);
1811 __release(rq2
->lock
);
1816 #ifdef CONFIG_FAIR_GROUP_SCHED
1817 static void cfs_rq_set_shares(struct cfs_rq
*cfs_rq
, unsigned long shares
)
1820 cfs_rq
->shares
= shares
;
1825 static void calc_load_account_idle(struct rq
*this_rq
);
1826 static void update_sysctl(void);
1827 static int get_update_sysctl_factor(void);
1828 static void update_cpu_load(struct rq
*this_rq
);
1830 static inline void __set_task_cpu(struct task_struct
*p
, unsigned int cpu
)
1832 set_task_rq(p
, cpu
);
1835 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1836 * successfuly executed on another CPU. We must ensure that updates of
1837 * per-task data have been completed by this moment.
1840 task_thread_info(p
)->cpu
= cpu
;
1844 static const struct sched_class rt_sched_class
;
1846 #define sched_class_highest (&rt_sched_class)
1847 #define for_each_class(class) \
1848 for (class = sched_class_highest; class; class = class->next)
1850 #include "sched_stats.h"
1852 static void inc_nr_running(struct rq
*rq
)
1857 static void dec_nr_running(struct rq
*rq
)
1862 static void set_load_weight(struct task_struct
*p
)
1864 if (task_has_rt_policy(p
)) {
1865 p
->se
.load
.weight
= 0;
1866 p
->se
.load
.inv_weight
= WMULT_CONST
;
1871 * SCHED_IDLE tasks get minimal weight:
1873 if (p
->policy
== SCHED_IDLE
) {
1874 p
->se
.load
.weight
= WEIGHT_IDLEPRIO
;
1875 p
->se
.load
.inv_weight
= WMULT_IDLEPRIO
;
1879 p
->se
.load
.weight
= prio_to_weight
[p
->static_prio
- MAX_RT_PRIO
];
1880 p
->se
.load
.inv_weight
= prio_to_wmult
[p
->static_prio
- MAX_RT_PRIO
];
1883 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
1885 update_rq_clock(rq
);
1886 sched_info_queued(p
);
1887 p
->sched_class
->enqueue_task(rq
, p
, flags
);
1891 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
1893 update_rq_clock(rq
);
1894 sched_info_dequeued(p
);
1895 p
->sched_class
->dequeue_task(rq
, p
, flags
);
1900 * activate_task - move a task to the runqueue.
1902 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
1904 if (task_contributes_to_load(p
))
1905 rq
->nr_uninterruptible
--;
1907 enqueue_task(rq
, p
, flags
);
1912 * deactivate_task - remove a task from the runqueue.
1914 static void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
1916 if (task_contributes_to_load(p
))
1917 rq
->nr_uninterruptible
++;
1919 dequeue_task(rq
, p
, flags
);
1923 #include "sched_idletask.c"
1924 #include "sched_fair.c"
1925 #include "sched_rt.c"
1926 #ifdef CONFIG_SCHED_DEBUG
1927 # include "sched_debug.c"
1931 * __normal_prio - return the priority that is based on the static prio
1933 static inline int __normal_prio(struct task_struct
*p
)
1935 return p
->static_prio
;
1939 * Calculate the expected normal priority: i.e. priority
1940 * without taking RT-inheritance into account. Might be
1941 * boosted by interactivity modifiers. Changes upon fork,
1942 * setprio syscalls, and whenever the interactivity
1943 * estimator recalculates.
1945 static inline int normal_prio(struct task_struct
*p
)
1949 if (task_has_rt_policy(p
))
1950 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
1952 prio
= __normal_prio(p
);
1957 * Calculate the current priority, i.e. the priority
1958 * taken into account by the scheduler. This value might
1959 * be boosted by RT tasks, or might be boosted by
1960 * interactivity modifiers. Will be RT if the task got
1961 * RT-boosted. If not then it returns p->normal_prio.
1963 static int effective_prio(struct task_struct
*p
)
1965 p
->normal_prio
= normal_prio(p
);
1967 * If we are RT tasks or we were boosted to RT priority,
1968 * keep the priority unchanged. Otherwise, update priority
1969 * to the normal priority:
1971 if (!rt_prio(p
->prio
))
1972 return p
->normal_prio
;
1977 * task_curr - is this task currently executing on a CPU?
1978 * @p: the task in question.
1980 inline int task_curr(const struct task_struct
*p
)
1982 return cpu_curr(task_cpu(p
)) == p
;
1985 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
1986 const struct sched_class
*prev_class
,
1987 int oldprio
, int running
)
1989 if (prev_class
!= p
->sched_class
) {
1990 if (prev_class
->switched_from
)
1991 prev_class
->switched_from(rq
, p
, running
);
1992 p
->sched_class
->switched_to(rq
, p
, running
);
1994 p
->sched_class
->prio_changed(rq
, p
, oldprio
, running
);
1999 * Is this task likely cache-hot:
2002 task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
)
2006 if (p
->sched_class
!= &fair_sched_class
)
2010 * Buddy candidates are cache hot:
2012 if (sched_feat(CACHE_HOT_BUDDY
) && this_rq()->nr_running
&&
2013 (&p
->se
== cfs_rq_of(&p
->se
)->next
||
2014 &p
->se
== cfs_rq_of(&p
->se
)->last
))
2017 if (sysctl_sched_migration_cost
== -1)
2019 if (sysctl_sched_migration_cost
== 0)
2022 delta
= now
- p
->se
.exec_start
;
2024 return delta
< (s64
)sysctl_sched_migration_cost
;
2027 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
2029 #ifdef CONFIG_SCHED_DEBUG
2031 * We should never call set_task_cpu() on a blocked task,
2032 * ttwu() will sort out the placement.
2034 WARN_ON_ONCE(p
->state
!= TASK_RUNNING
&& p
->state
!= TASK_WAKING
&&
2035 !(task_thread_info(p
)->preempt_count
& PREEMPT_ACTIVE
));
2038 trace_sched_migrate_task(p
, new_cpu
);
2040 if (task_cpu(p
) != new_cpu
) {
2041 p
->se
.nr_migrations
++;
2042 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS
, 1, 1, NULL
, 0);
2045 __set_task_cpu(p
, new_cpu
);
2048 struct migration_arg
{
2049 struct task_struct
*task
;
2053 static int migration_cpu_stop(void *data
);
2056 * The task's runqueue lock must be held.
2057 * Returns true if you have to wait for migration thread.
2059 static bool migrate_task(struct task_struct
*p
, int dest_cpu
)
2061 struct rq
*rq
= task_rq(p
);
2064 * If the task is not on a runqueue (and not running), then
2065 * the next wake-up will properly place the task.
2067 return p
->se
.on_rq
|| task_running(rq
, p
);
2071 * wait_task_inactive - wait for a thread to unschedule.
2073 * If @match_state is nonzero, it's the @p->state value just checked and
2074 * not expected to change. If it changes, i.e. @p might have woken up,
2075 * then return zero. When we succeed in waiting for @p to be off its CPU,
2076 * we return a positive number (its total switch count). If a second call
2077 * a short while later returns the same number, the caller can be sure that
2078 * @p has remained unscheduled the whole time.
2080 * The caller must ensure that the task *will* unschedule sometime soon,
2081 * else this function might spin for a *long* time. This function can't
2082 * be called with interrupts off, or it may introduce deadlock with
2083 * smp_call_function() if an IPI is sent by the same process we are
2084 * waiting to become inactive.
2086 unsigned long wait_task_inactive(struct task_struct
*p
, long match_state
)
2088 unsigned long flags
;
2095 * We do the initial early heuristics without holding
2096 * any task-queue locks at all. We'll only try to get
2097 * the runqueue lock when things look like they will
2103 * If the task is actively running on another CPU
2104 * still, just relax and busy-wait without holding
2107 * NOTE! Since we don't hold any locks, it's not
2108 * even sure that "rq" stays as the right runqueue!
2109 * But we don't care, since "task_running()" will
2110 * return false if the runqueue has changed and p
2111 * is actually now running somewhere else!
2113 while (task_running(rq
, p
)) {
2114 if (match_state
&& unlikely(p
->state
!= match_state
))
2120 * Ok, time to look more closely! We need the rq
2121 * lock now, to be *sure*. If we're wrong, we'll
2122 * just go back and repeat.
2124 rq
= task_rq_lock(p
, &flags
);
2125 trace_sched_wait_task(p
);
2126 running
= task_running(rq
, p
);
2127 on_rq
= p
->se
.on_rq
;
2129 if (!match_state
|| p
->state
== match_state
)
2130 ncsw
= p
->nvcsw
| LONG_MIN
; /* sets MSB */
2131 task_rq_unlock(rq
, &flags
);
2134 * If it changed from the expected state, bail out now.
2136 if (unlikely(!ncsw
))
2140 * Was it really running after all now that we
2141 * checked with the proper locks actually held?
2143 * Oops. Go back and try again..
2145 if (unlikely(running
)) {
2151 * It's not enough that it's not actively running,
2152 * it must be off the runqueue _entirely_, and not
2155 * So if it was still runnable (but just not actively
2156 * running right now), it's preempted, and we should
2157 * yield - it could be a while.
2159 if (unlikely(on_rq
)) {
2160 schedule_timeout_uninterruptible(1);
2165 * Ahh, all good. It wasn't running, and it wasn't
2166 * runnable, which means that it will never become
2167 * running in the future either. We're all done!
2176 * kick_process - kick a running thread to enter/exit the kernel
2177 * @p: the to-be-kicked thread
2179 * Cause a process which is running on another CPU to enter
2180 * kernel-mode, without any delay. (to get signals handled.)
2182 * NOTE: this function doesnt have to take the runqueue lock,
2183 * because all it wants to ensure is that the remote task enters
2184 * the kernel. If the IPI races and the task has been migrated
2185 * to another CPU then no harm is done and the purpose has been
2188 void kick_process(struct task_struct
*p
)
2194 if ((cpu
!= smp_processor_id()) && task_curr(p
))
2195 smp_send_reschedule(cpu
);
2198 EXPORT_SYMBOL_GPL(kick_process
);
2199 #endif /* CONFIG_SMP */
2202 * task_oncpu_function_call - call a function on the cpu on which a task runs
2203 * @p: the task to evaluate
2204 * @func: the function to be called
2205 * @info: the function call argument
2207 * Calls the function @func when the task is currently running. This might
2208 * be on the current CPU, which just calls the function directly
2210 void task_oncpu_function_call(struct task_struct
*p
,
2211 void (*func
) (void *info
), void *info
)
2218 smp_call_function_single(cpu
, func
, info
, 1);
2224 * ->cpus_allowed is protected by either TASK_WAKING or rq->lock held.
2226 static int select_fallback_rq(int cpu
, struct task_struct
*p
)
2229 const struct cpumask
*nodemask
= cpumask_of_node(cpu_to_node(cpu
));
2231 /* Look for allowed, online CPU in same node. */
2232 for_each_cpu_and(dest_cpu
, nodemask
, cpu_active_mask
)
2233 if (cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
2236 /* Any allowed, online CPU? */
2237 dest_cpu
= cpumask_any_and(&p
->cpus_allowed
, cpu_active_mask
);
2238 if (dest_cpu
< nr_cpu_ids
)
2241 /* No more Mr. Nice Guy. */
2242 if (unlikely(dest_cpu
>= nr_cpu_ids
)) {
2243 dest_cpu
= cpuset_cpus_allowed_fallback(p
);
2245 * Don't tell them about moving exiting tasks or
2246 * kernel threads (both mm NULL), since they never
2249 if (p
->mm
&& printk_ratelimit()) {
2250 printk(KERN_INFO
"process %d (%s) no "
2251 "longer affine to cpu%d\n",
2252 task_pid_nr(p
), p
->comm
, cpu
);
2260 * The caller (fork, wakeup) owns TASK_WAKING, ->cpus_allowed is stable.
2263 int select_task_rq(struct rq
*rq
, struct task_struct
*p
, int sd_flags
, int wake_flags
)
2265 int cpu
= p
->sched_class
->select_task_rq(rq
, p
, sd_flags
, wake_flags
);
2268 * In order not to call set_task_cpu() on a blocking task we need
2269 * to rely on ttwu() to place the task on a valid ->cpus_allowed
2272 * Since this is common to all placement strategies, this lives here.
2274 * [ this allows ->select_task() to simply return task_cpu(p) and
2275 * not worry about this generic constraint ]
2277 if (unlikely(!cpumask_test_cpu(cpu
, &p
->cpus_allowed
) ||
2279 cpu
= select_fallback_rq(task_cpu(p
), p
);
2284 static void update_avg(u64
*avg
, u64 sample
)
2286 s64 diff
= sample
- *avg
;
2291 static inline void ttwu_activate(struct task_struct
*p
, struct rq
*rq
,
2292 bool is_sync
, bool is_migrate
, bool is_local
,
2293 unsigned long en_flags
)
2295 schedstat_inc(p
, se
.statistics
.nr_wakeups
);
2297 schedstat_inc(p
, se
.statistics
.nr_wakeups_sync
);
2299 schedstat_inc(p
, se
.statistics
.nr_wakeups_migrate
);
2301 schedstat_inc(p
, se
.statistics
.nr_wakeups_local
);
2303 schedstat_inc(p
, se
.statistics
.nr_wakeups_remote
);
2305 activate_task(rq
, p
, en_flags
);
2308 static inline void ttwu_post_activation(struct task_struct
*p
, struct rq
*rq
,
2309 int wake_flags
, bool success
)
2311 trace_sched_wakeup(p
, success
);
2312 check_preempt_curr(rq
, p
, wake_flags
);
2314 p
->state
= TASK_RUNNING
;
2316 if (p
->sched_class
->task_woken
)
2317 p
->sched_class
->task_woken(rq
, p
);
2319 if (unlikely(rq
->idle_stamp
)) {
2320 u64 delta
= rq
->clock
- rq
->idle_stamp
;
2321 u64 max
= 2*sysctl_sched_migration_cost
;
2326 update_avg(&rq
->avg_idle
, delta
);
2330 /* if a worker is waking up, notify workqueue */
2331 if ((p
->flags
& PF_WQ_WORKER
) && success
)
2332 wq_worker_waking_up(p
, cpu_of(rq
));
2336 * try_to_wake_up - wake up a thread
2337 * @p: the thread to be awakened
2338 * @state: the mask of task states that can be woken
2339 * @wake_flags: wake modifier flags (WF_*)
2341 * Put it on the run-queue if it's not already there. The "current"
2342 * thread is always on the run-queue (except when the actual
2343 * re-schedule is in progress), and as such you're allowed to do
2344 * the simpler "current->state = TASK_RUNNING" to mark yourself
2345 * runnable without the overhead of this.
2347 * Returns %true if @p was woken up, %false if it was already running
2348 * or @state didn't match @p's state.
2350 static int try_to_wake_up(struct task_struct
*p
, unsigned int state
,
2353 int cpu
, orig_cpu
, this_cpu
, success
= 0;
2354 unsigned long flags
;
2355 unsigned long en_flags
= ENQUEUE_WAKEUP
;
2358 this_cpu
= get_cpu();
2361 rq
= task_rq_lock(p
, &flags
);
2362 if (!(p
->state
& state
))
2372 if (unlikely(task_running(rq
, p
)))
2376 * In order to handle concurrent wakeups and release the rq->lock
2377 * we put the task in TASK_WAKING state.
2379 * First fix up the nr_uninterruptible count:
2381 if (task_contributes_to_load(p
)) {
2382 if (likely(cpu_online(orig_cpu
)))
2383 rq
->nr_uninterruptible
--;
2385 this_rq()->nr_uninterruptible
--;
2387 p
->state
= TASK_WAKING
;
2389 if (p
->sched_class
->task_waking
) {
2390 p
->sched_class
->task_waking(rq
, p
);
2391 en_flags
|= ENQUEUE_WAKING
;
2394 cpu
= select_task_rq(rq
, p
, SD_BALANCE_WAKE
, wake_flags
);
2395 if (cpu
!= orig_cpu
)
2396 set_task_cpu(p
, cpu
);
2397 __task_rq_unlock(rq
);
2400 raw_spin_lock(&rq
->lock
);
2403 * We migrated the task without holding either rq->lock, however
2404 * since the task is not on the task list itself, nobody else
2405 * will try and migrate the task, hence the rq should match the
2406 * cpu we just moved it to.
2408 WARN_ON(task_cpu(p
) != cpu
);
2409 WARN_ON(p
->state
!= TASK_WAKING
);
2411 #ifdef CONFIG_SCHEDSTATS
2412 schedstat_inc(rq
, ttwu_count
);
2413 if (cpu
== this_cpu
)
2414 schedstat_inc(rq
, ttwu_local
);
2416 struct sched_domain
*sd
;
2417 for_each_domain(this_cpu
, sd
) {
2418 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
2419 schedstat_inc(sd
, ttwu_wake_remote
);
2424 #endif /* CONFIG_SCHEDSTATS */
2427 #endif /* CONFIG_SMP */
2428 ttwu_activate(p
, rq
, wake_flags
& WF_SYNC
, orig_cpu
!= cpu
,
2429 cpu
== this_cpu
, en_flags
);
2432 ttwu_post_activation(p
, rq
, wake_flags
, success
);
2434 task_rq_unlock(rq
, &flags
);
2441 * try_to_wake_up_local - try to wake up a local task with rq lock held
2442 * @p: the thread to be awakened
2444 * Put @p on the run-queue if it's not alredy there. The caller must
2445 * ensure that this_rq() is locked, @p is bound to this_rq() and not
2446 * the current task. this_rq() stays locked over invocation.
2448 static void try_to_wake_up_local(struct task_struct
*p
)
2450 struct rq
*rq
= task_rq(p
);
2451 bool success
= false;
2453 BUG_ON(rq
!= this_rq());
2454 BUG_ON(p
== current
);
2455 lockdep_assert_held(&rq
->lock
);
2457 if (!(p
->state
& TASK_NORMAL
))
2461 if (likely(!task_running(rq
, p
))) {
2462 schedstat_inc(rq
, ttwu_count
);
2463 schedstat_inc(rq
, ttwu_local
);
2465 ttwu_activate(p
, rq
, false, false, true, ENQUEUE_WAKEUP
);
2468 ttwu_post_activation(p
, rq
, 0, success
);
2472 * wake_up_process - Wake up a specific process
2473 * @p: The process to be woken up.
2475 * Attempt to wake up the nominated process and move it to the set of runnable
2476 * processes. Returns 1 if the process was woken up, 0 if it was already
2479 * It may be assumed that this function implies a write memory barrier before
2480 * changing the task state if and only if any tasks are woken up.
2482 int wake_up_process(struct task_struct
*p
)
2484 return try_to_wake_up(p
, TASK_ALL
, 0);
2486 EXPORT_SYMBOL(wake_up_process
);
2488 int wake_up_state(struct task_struct
*p
, unsigned int state
)
2490 return try_to_wake_up(p
, state
, 0);
2494 * Perform scheduler related setup for a newly forked process p.
2495 * p is forked by current.
2497 * __sched_fork() is basic setup used by init_idle() too:
2499 static void __sched_fork(struct task_struct
*p
)
2501 p
->se
.exec_start
= 0;
2502 p
->se
.sum_exec_runtime
= 0;
2503 p
->se
.prev_sum_exec_runtime
= 0;
2504 p
->se
.nr_migrations
= 0;
2506 #ifdef CONFIG_SCHEDSTATS
2507 memset(&p
->se
.statistics
, 0, sizeof(p
->se
.statistics
));
2510 INIT_LIST_HEAD(&p
->rt
.run_list
);
2512 INIT_LIST_HEAD(&p
->se
.group_node
);
2514 #ifdef CONFIG_PREEMPT_NOTIFIERS
2515 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
2520 * fork()/clone()-time setup:
2522 void sched_fork(struct task_struct
*p
, int clone_flags
)
2524 int cpu
= get_cpu();
2528 * We mark the process as running here. This guarantees that
2529 * nobody will actually run it, and a signal or other external
2530 * event cannot wake it up and insert it on the runqueue either.
2532 p
->state
= TASK_RUNNING
;
2535 * Revert to default priority/policy on fork if requested.
2537 if (unlikely(p
->sched_reset_on_fork
)) {
2538 if (p
->policy
== SCHED_FIFO
|| p
->policy
== SCHED_RR
) {
2539 p
->policy
= SCHED_NORMAL
;
2540 p
->normal_prio
= p
->static_prio
;
2543 if (PRIO_TO_NICE(p
->static_prio
) < 0) {
2544 p
->static_prio
= NICE_TO_PRIO(0);
2545 p
->normal_prio
= p
->static_prio
;
2550 * We don't need the reset flag anymore after the fork. It has
2551 * fulfilled its duty:
2553 p
->sched_reset_on_fork
= 0;
2557 * Make sure we do not leak PI boosting priority to the child.
2559 p
->prio
= current
->normal_prio
;
2561 if (!rt_prio(p
->prio
))
2562 p
->sched_class
= &fair_sched_class
;
2564 if (p
->sched_class
->task_fork
)
2565 p
->sched_class
->task_fork(p
);
2567 set_task_cpu(p
, cpu
);
2569 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2570 if (likely(sched_info_on()))
2571 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
2573 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
2576 #ifdef CONFIG_PREEMPT
2577 /* Want to start with kernel preemption disabled. */
2578 task_thread_info(p
)->preempt_count
= 1;
2580 plist_node_init(&p
->pushable_tasks
, MAX_PRIO
);
2586 * wake_up_new_task - wake up a newly created task for the first time.
2588 * This function will do some initial scheduler statistics housekeeping
2589 * that must be done for every newly created context, then puts the task
2590 * on the runqueue and wakes it.
2592 void wake_up_new_task(struct task_struct
*p
, unsigned long clone_flags
)
2594 unsigned long flags
;
2596 int cpu __maybe_unused
= get_cpu();
2599 rq
= task_rq_lock(p
, &flags
);
2600 p
->state
= TASK_WAKING
;
2603 * Fork balancing, do it here and not earlier because:
2604 * - cpus_allowed can change in the fork path
2605 * - any previously selected cpu might disappear through hotplug
2607 * We set TASK_WAKING so that select_task_rq() can drop rq->lock
2608 * without people poking at ->cpus_allowed.
2610 cpu
= select_task_rq(rq
, p
, SD_BALANCE_FORK
, 0);
2611 set_task_cpu(p
, cpu
);
2613 p
->state
= TASK_RUNNING
;
2614 task_rq_unlock(rq
, &flags
);
2617 rq
= task_rq_lock(p
, &flags
);
2618 activate_task(rq
, p
, 0);
2619 trace_sched_wakeup_new(p
, 1);
2620 check_preempt_curr(rq
, p
, WF_FORK
);
2622 if (p
->sched_class
->task_woken
)
2623 p
->sched_class
->task_woken(rq
, p
);
2625 task_rq_unlock(rq
, &flags
);
2629 #ifdef CONFIG_PREEMPT_NOTIFIERS
2632 * preempt_notifier_register - tell me when current is being preempted & rescheduled
2633 * @notifier: notifier struct to register
2635 void preempt_notifier_register(struct preempt_notifier
*notifier
)
2637 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
2639 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
2642 * preempt_notifier_unregister - no longer interested in preemption notifications
2643 * @notifier: notifier struct to unregister
2645 * This is safe to call from within a preemption notifier.
2647 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
2649 hlist_del(¬ifier
->link
);
2651 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
2653 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2655 struct preempt_notifier
*notifier
;
2656 struct hlist_node
*node
;
2658 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2659 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
2663 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2664 struct task_struct
*next
)
2666 struct preempt_notifier
*notifier
;
2667 struct hlist_node
*node
;
2669 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2670 notifier
->ops
->sched_out(notifier
, next
);
2673 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2675 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2680 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2681 struct task_struct
*next
)
2685 #endif /* CONFIG_PREEMPT_NOTIFIERS */
2688 * prepare_task_switch - prepare to switch tasks
2689 * @rq: the runqueue preparing to switch
2690 * @prev: the current task that is being switched out
2691 * @next: the task we are going to switch to.
2693 * This is called with the rq lock held and interrupts off. It must
2694 * be paired with a subsequent finish_task_switch after the context
2697 * prepare_task_switch sets up locking and calls architecture specific
2701 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
2702 struct task_struct
*next
)
2704 fire_sched_out_preempt_notifiers(prev
, next
);
2705 prepare_lock_switch(rq
, next
);
2706 prepare_arch_switch(next
);
2710 * finish_task_switch - clean up after a task-switch
2711 * @rq: runqueue associated with task-switch
2712 * @prev: the thread we just switched away from.
2714 * finish_task_switch must be called after the context switch, paired
2715 * with a prepare_task_switch call before the context switch.
2716 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2717 * and do any other architecture-specific cleanup actions.
2719 * Note that we may have delayed dropping an mm in context_switch(). If
2720 * so, we finish that here outside of the runqueue lock. (Doing it
2721 * with the lock held can cause deadlocks; see schedule() for
2724 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
2725 __releases(rq
->lock
)
2727 struct mm_struct
*mm
= rq
->prev_mm
;
2733 * A task struct has one reference for the use as "current".
2734 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2735 * schedule one last time. The schedule call will never return, and
2736 * the scheduled task must drop that reference.
2737 * The test for TASK_DEAD must occur while the runqueue locks are
2738 * still held, otherwise prev could be scheduled on another cpu, die
2739 * there before we look at prev->state, and then the reference would
2741 * Manfred Spraul <manfred@colorfullife.com>
2743 prev_state
= prev
->state
;
2744 finish_arch_switch(prev
);
2745 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
2746 local_irq_disable();
2747 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
2748 perf_event_task_sched_in(current
);
2749 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
2751 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
2752 finish_lock_switch(rq
, prev
);
2754 fire_sched_in_preempt_notifiers(current
);
2757 if (unlikely(prev_state
== TASK_DEAD
)) {
2759 * Remove function-return probe instances associated with this
2760 * task and put them back on the free list.
2762 kprobe_flush_task(prev
);
2763 put_task_struct(prev
);
2769 /* assumes rq->lock is held */
2770 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*prev
)
2772 if (prev
->sched_class
->pre_schedule
)
2773 prev
->sched_class
->pre_schedule(rq
, prev
);
2776 /* rq->lock is NOT held, but preemption is disabled */
2777 static inline void post_schedule(struct rq
*rq
)
2779 if (rq
->post_schedule
) {
2780 unsigned long flags
;
2782 raw_spin_lock_irqsave(&rq
->lock
, flags
);
2783 if (rq
->curr
->sched_class
->post_schedule
)
2784 rq
->curr
->sched_class
->post_schedule(rq
);
2785 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
2787 rq
->post_schedule
= 0;
2793 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*p
)
2797 static inline void post_schedule(struct rq
*rq
)
2804 * schedule_tail - first thing a freshly forked thread must call.
2805 * @prev: the thread we just switched away from.
2807 asmlinkage
void schedule_tail(struct task_struct
*prev
)
2808 __releases(rq
->lock
)
2810 struct rq
*rq
= this_rq();
2812 finish_task_switch(rq
, prev
);
2815 * FIXME: do we need to worry about rq being invalidated by the
2820 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2821 /* In this case, finish_task_switch does not reenable preemption */
2824 if (current
->set_child_tid
)
2825 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2829 * context_switch - switch to the new MM and the new
2830 * thread's register state.
2833 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2834 struct task_struct
*next
)
2836 struct mm_struct
*mm
, *oldmm
;
2838 prepare_task_switch(rq
, prev
, next
);
2839 trace_sched_switch(prev
, next
);
2841 oldmm
= prev
->active_mm
;
2843 * For paravirt, this is coupled with an exit in switch_to to
2844 * combine the page table reload and the switch backend into
2847 arch_start_context_switch(prev
);
2850 next
->active_mm
= oldmm
;
2851 atomic_inc(&oldmm
->mm_count
);
2852 enter_lazy_tlb(oldmm
, next
);
2854 switch_mm(oldmm
, mm
, next
);
2856 if (likely(!prev
->mm
)) {
2857 prev
->active_mm
= NULL
;
2858 rq
->prev_mm
= oldmm
;
2861 * Since the runqueue lock will be released by the next
2862 * task (which is an invalid locking op but in the case
2863 * of the scheduler it's an obvious special-case), so we
2864 * do an early lockdep release here:
2866 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2867 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2870 /* Here we just switch the register state and the stack. */
2871 switch_to(prev
, next
, prev
);
2875 * this_rq must be evaluated again because prev may have moved
2876 * CPUs since it called schedule(), thus the 'rq' on its stack
2877 * frame will be invalid.
2879 finish_task_switch(this_rq(), prev
);
2883 * nr_running, nr_uninterruptible and nr_context_switches:
2885 * externally visible scheduler statistics: current number of runnable
2886 * threads, current number of uninterruptible-sleeping threads, total
2887 * number of context switches performed since bootup.
2889 unsigned long nr_running(void)
2891 unsigned long i
, sum
= 0;
2893 for_each_online_cpu(i
)
2894 sum
+= cpu_rq(i
)->nr_running
;
2899 unsigned long nr_uninterruptible(void)
2901 unsigned long i
, sum
= 0;
2903 for_each_possible_cpu(i
)
2904 sum
+= cpu_rq(i
)->nr_uninterruptible
;
2907 * Since we read the counters lockless, it might be slightly
2908 * inaccurate. Do not allow it to go below zero though:
2910 if (unlikely((long)sum
< 0))
2916 unsigned long long nr_context_switches(void)
2919 unsigned long long sum
= 0;
2921 for_each_possible_cpu(i
)
2922 sum
+= cpu_rq(i
)->nr_switches
;
2927 unsigned long nr_iowait(void)
2929 unsigned long i
, sum
= 0;
2931 for_each_possible_cpu(i
)
2932 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2937 unsigned long nr_iowait_cpu(void)
2939 struct rq
*this = this_rq();
2940 return atomic_read(&this->nr_iowait
);
2943 unsigned long this_cpu_load(void)
2945 struct rq
*this = this_rq();
2946 return this->cpu_load
[0];
2950 /* Variables and functions for calc_load */
2951 static atomic_long_t calc_load_tasks
;
2952 static unsigned long calc_load_update
;
2953 unsigned long avenrun
[3];
2954 EXPORT_SYMBOL(avenrun
);
2956 static long calc_load_fold_active(struct rq
*this_rq
)
2958 long nr_active
, delta
= 0;
2960 nr_active
= this_rq
->nr_running
;
2961 nr_active
+= (long) this_rq
->nr_uninterruptible
;
2963 if (nr_active
!= this_rq
->calc_load_active
) {
2964 delta
= nr_active
- this_rq
->calc_load_active
;
2965 this_rq
->calc_load_active
= nr_active
;
2973 * For NO_HZ we delay the active fold to the next LOAD_FREQ update.
2975 * When making the ILB scale, we should try to pull this in as well.
2977 static atomic_long_t calc_load_tasks_idle
;
2979 static void calc_load_account_idle(struct rq
*this_rq
)
2983 delta
= calc_load_fold_active(this_rq
);
2985 atomic_long_add(delta
, &calc_load_tasks_idle
);
2988 static long calc_load_fold_idle(void)
2993 * Its got a race, we don't care...
2995 if (atomic_long_read(&calc_load_tasks_idle
))
2996 delta
= atomic_long_xchg(&calc_load_tasks_idle
, 0);
3001 static void calc_load_account_idle(struct rq
*this_rq
)
3005 static inline long calc_load_fold_idle(void)
3012 * get_avenrun - get the load average array
3013 * @loads: pointer to dest load array
3014 * @offset: offset to add
3015 * @shift: shift count to shift the result left
3017 * These values are estimates at best, so no need for locking.
3019 void get_avenrun(unsigned long *loads
, unsigned long offset
, int shift
)
3021 loads
[0] = (avenrun
[0] + offset
) << shift
;
3022 loads
[1] = (avenrun
[1] + offset
) << shift
;
3023 loads
[2] = (avenrun
[2] + offset
) << shift
;
3026 static unsigned long
3027 calc_load(unsigned long load
, unsigned long exp
, unsigned long active
)
3030 load
+= active
* (FIXED_1
- exp
);
3031 return load
>> FSHIFT
;
3035 * calc_load - update the avenrun load estimates 10 ticks after the
3036 * CPUs have updated calc_load_tasks.
3038 void calc_global_load(void)
3040 unsigned long upd
= calc_load_update
+ 10;
3043 if (time_before(jiffies
, upd
))
3046 active
= atomic_long_read(&calc_load_tasks
);
3047 active
= active
> 0 ? active
* FIXED_1
: 0;
3049 avenrun
[0] = calc_load(avenrun
[0], EXP_1
, active
);
3050 avenrun
[1] = calc_load(avenrun
[1], EXP_5
, active
);
3051 avenrun
[2] = calc_load(avenrun
[2], EXP_15
, active
);
3053 calc_load_update
+= LOAD_FREQ
;
3057 * Called from update_cpu_load() to periodically update this CPU's
3060 static void calc_load_account_active(struct rq
*this_rq
)
3064 if (time_before(jiffies
, this_rq
->calc_load_update
))
3067 delta
= calc_load_fold_active(this_rq
);
3068 delta
+= calc_load_fold_idle();
3070 atomic_long_add(delta
, &calc_load_tasks
);
3072 this_rq
->calc_load_update
+= LOAD_FREQ
;
3076 * The exact cpuload at various idx values, calculated at every tick would be
3077 * load = (2^idx - 1) / 2^idx * load + 1 / 2^idx * cur_load
3079 * If a cpu misses updates for n-1 ticks (as it was idle) and update gets called
3080 * on nth tick when cpu may be busy, then we have:
3081 * load = ((2^idx - 1) / 2^idx)^(n-1) * load
3082 * load = (2^idx - 1) / 2^idx) * load + 1 / 2^idx * cur_load
3084 * decay_load_missed() below does efficient calculation of
3085 * load = ((2^idx - 1) / 2^idx)^(n-1) * load
3086 * avoiding 0..n-1 loop doing load = ((2^idx - 1) / 2^idx) * load
3088 * The calculation is approximated on a 128 point scale.
3089 * degrade_zero_ticks is the number of ticks after which load at any
3090 * particular idx is approximated to be zero.
3091 * degrade_factor is a precomputed table, a row for each load idx.
3092 * Each column corresponds to degradation factor for a power of two ticks,
3093 * based on 128 point scale.
3095 * row 2, col 3 (=12) says that the degradation at load idx 2 after
3096 * 8 ticks is 12/128 (which is an approximation of exact factor 3^8/4^8).
3098 * With this power of 2 load factors, we can degrade the load n times
3099 * by looking at 1 bits in n and doing as many mult/shift instead of
3100 * n mult/shifts needed by the exact degradation.
3102 #define DEGRADE_SHIFT 7
3103 static const unsigned char
3104 degrade_zero_ticks
[CPU_LOAD_IDX_MAX
] = {0, 8, 32, 64, 128};
3105 static const unsigned char
3106 degrade_factor
[CPU_LOAD_IDX_MAX
][DEGRADE_SHIFT
+ 1] = {
3107 {0, 0, 0, 0, 0, 0, 0, 0},
3108 {64, 32, 8, 0, 0, 0, 0, 0},
3109 {96, 72, 40, 12, 1, 0, 0},
3110 {112, 98, 75, 43, 15, 1, 0},
3111 {120, 112, 98, 76, 45, 16, 2} };
3114 * Update cpu_load for any missed ticks, due to tickless idle. The backlog
3115 * would be when CPU is idle and so we just decay the old load without
3116 * adding any new load.
3118 static unsigned long
3119 decay_load_missed(unsigned long load
, unsigned long missed_updates
, int idx
)
3123 if (!missed_updates
)
3126 if (missed_updates
>= degrade_zero_ticks
[idx
])
3130 return load
>> missed_updates
;
3132 while (missed_updates
) {
3133 if (missed_updates
% 2)
3134 load
= (load
* degrade_factor
[idx
][j
]) >> DEGRADE_SHIFT
;
3136 missed_updates
>>= 1;
3143 * Update rq->cpu_load[] statistics. This function is usually called every
3144 * scheduler tick (TICK_NSEC). With tickless idle this will not be called
3145 * every tick. We fix it up based on jiffies.
3147 static void update_cpu_load(struct rq
*this_rq
)
3149 unsigned long this_load
= this_rq
->load
.weight
;
3150 unsigned long curr_jiffies
= jiffies
;
3151 unsigned long pending_updates
;
3154 this_rq
->nr_load_updates
++;
3156 /* Avoid repeated calls on same jiffy, when moving in and out of idle */
3157 if (curr_jiffies
== this_rq
->last_load_update_tick
)
3160 pending_updates
= curr_jiffies
- this_rq
->last_load_update_tick
;
3161 this_rq
->last_load_update_tick
= curr_jiffies
;
3163 /* Update our load: */
3164 this_rq
->cpu_load
[0] = this_load
; /* Fasttrack for idx 0 */
3165 for (i
= 1, scale
= 2; i
< CPU_LOAD_IDX_MAX
; i
++, scale
+= scale
) {
3166 unsigned long old_load
, new_load
;
3168 /* scale is effectively 1 << i now, and >> i divides by scale */
3170 old_load
= this_rq
->cpu_load
[i
];
3171 old_load
= decay_load_missed(old_load
, pending_updates
- 1, i
);
3172 new_load
= this_load
;
3174 * Round up the averaging division if load is increasing. This
3175 * prevents us from getting stuck on 9 if the load is 10, for
3178 if (new_load
> old_load
)
3179 new_load
+= scale
- 1;
3181 this_rq
->cpu_load
[i
] = (old_load
* (scale
- 1) + new_load
) >> i
;
3185 static void update_cpu_load_active(struct rq
*this_rq
)
3187 update_cpu_load(this_rq
);
3189 calc_load_account_active(this_rq
);
3195 * sched_exec - execve() is a valuable balancing opportunity, because at
3196 * this point the task has the smallest effective memory and cache footprint.
3198 void sched_exec(void)
3200 struct task_struct
*p
= current
;
3201 unsigned long flags
;
3205 rq
= task_rq_lock(p
, &flags
);
3206 dest_cpu
= p
->sched_class
->select_task_rq(rq
, p
, SD_BALANCE_EXEC
, 0);
3207 if (dest_cpu
== smp_processor_id())
3211 * select_task_rq() can race against ->cpus_allowed
3213 if (cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
) &&
3214 likely(cpu_active(dest_cpu
)) && migrate_task(p
, dest_cpu
)) {
3215 struct migration_arg arg
= { p
, dest_cpu
};
3217 task_rq_unlock(rq
, &flags
);
3218 stop_one_cpu(cpu_of(rq
), migration_cpu_stop
, &arg
);
3222 task_rq_unlock(rq
, &flags
);
3227 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
3229 EXPORT_PER_CPU_SYMBOL(kstat
);
3232 * Return any ns on the sched_clock that have not yet been accounted in
3233 * @p in case that task is currently running.
3235 * Called with task_rq_lock() held on @rq.
3237 static u64
do_task_delta_exec(struct task_struct
*p
, struct rq
*rq
)
3241 if (task_current(rq
, p
)) {
3242 update_rq_clock(rq
);
3243 ns
= rq
->clock
- p
->se
.exec_start
;
3251 unsigned long long task_delta_exec(struct task_struct
*p
)
3253 unsigned long flags
;
3257 rq
= task_rq_lock(p
, &flags
);
3258 ns
= do_task_delta_exec(p
, rq
);
3259 task_rq_unlock(rq
, &flags
);
3265 * Return accounted runtime for the task.
3266 * In case the task is currently running, return the runtime plus current's
3267 * pending runtime that have not been accounted yet.
3269 unsigned long long task_sched_runtime(struct task_struct
*p
)
3271 unsigned long flags
;
3275 rq
= task_rq_lock(p
, &flags
);
3276 ns
= p
->se
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
3277 task_rq_unlock(rq
, &flags
);
3283 * Return sum_exec_runtime for the thread group.
3284 * In case the task is currently running, return the sum plus current's
3285 * pending runtime that have not been accounted yet.
3287 * Note that the thread group might have other running tasks as well,
3288 * so the return value not includes other pending runtime that other
3289 * running tasks might have.
3291 unsigned long long thread_group_sched_runtime(struct task_struct
*p
)
3293 struct task_cputime totals
;
3294 unsigned long flags
;
3298 rq
= task_rq_lock(p
, &flags
);
3299 thread_group_cputime(p
, &totals
);
3300 ns
= totals
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
3301 task_rq_unlock(rq
, &flags
);
3307 * Account user cpu time to a process.
3308 * @p: the process that the cpu time gets accounted to
3309 * @cputime: the cpu time spent in user space since the last update
3310 * @cputime_scaled: cputime scaled by cpu frequency
3312 void account_user_time(struct task_struct
*p
, cputime_t cputime
,
3313 cputime_t cputime_scaled
)
3315 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3318 /* Add user time to process. */
3319 p
->utime
= cputime_add(p
->utime
, cputime
);
3320 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
3321 account_group_user_time(p
, cputime
);
3323 /* Add user time to cpustat. */
3324 tmp
= cputime_to_cputime64(cputime
);
3325 if (TASK_NICE(p
) > 0)
3326 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
3328 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
3330 cpuacct_update_stats(p
, CPUACCT_STAT_USER
, cputime
);
3331 /* Account for user time used */
3332 acct_update_integrals(p
);
3336 * Account guest cpu time to a process.
3337 * @p: the process that the cpu time gets accounted to
3338 * @cputime: the cpu time spent in virtual machine since the last update
3339 * @cputime_scaled: cputime scaled by cpu frequency
3341 static void account_guest_time(struct task_struct
*p
, cputime_t cputime
,
3342 cputime_t cputime_scaled
)
3345 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3347 tmp
= cputime_to_cputime64(cputime
);
3349 /* Add guest time to process. */
3350 p
->utime
= cputime_add(p
->utime
, cputime
);
3351 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
3352 account_group_user_time(p
, cputime
);
3353 p
->gtime
= cputime_add(p
->gtime
, cputime
);
3355 /* Add guest time to cpustat. */
3356 if (TASK_NICE(p
) > 0) {
3357 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
3358 cpustat
->guest_nice
= cputime64_add(cpustat
->guest_nice
, tmp
);
3360 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
3361 cpustat
->guest
= cputime64_add(cpustat
->guest
, tmp
);
3366 * Account system cpu time to a process.
3367 * @p: the process that the cpu time gets accounted to
3368 * @hardirq_offset: the offset to subtract from hardirq_count()
3369 * @cputime: the cpu time spent in kernel space since the last update
3370 * @cputime_scaled: cputime scaled by cpu frequency
3372 void account_system_time(struct task_struct
*p
, int hardirq_offset
,
3373 cputime_t cputime
, cputime_t cputime_scaled
)
3375 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3378 if ((p
->flags
& PF_VCPU
) && (irq_count() - hardirq_offset
== 0)) {
3379 account_guest_time(p
, cputime
, cputime_scaled
);
3383 /* Add system time to process. */
3384 p
->stime
= cputime_add(p
->stime
, cputime
);
3385 p
->stimescaled
= cputime_add(p
->stimescaled
, cputime_scaled
);
3386 account_group_system_time(p
, cputime
);
3388 /* Add system time to cpustat. */
3389 tmp
= cputime_to_cputime64(cputime
);
3390 if (hardirq_count() - hardirq_offset
)
3391 cpustat
->irq
= cputime64_add(cpustat
->irq
, tmp
);
3392 else if (softirq_count())
3393 cpustat
->softirq
= cputime64_add(cpustat
->softirq
, tmp
);
3395 cpustat
->system
= cputime64_add(cpustat
->system
, tmp
);
3397 cpuacct_update_stats(p
, CPUACCT_STAT_SYSTEM
, cputime
);
3399 /* Account for system time used */
3400 acct_update_integrals(p
);
3404 * Account for involuntary wait time.
3405 * @steal: the cpu time spent in involuntary wait
3407 void account_steal_time(cputime_t cputime
)
3409 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3410 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
3412 cpustat
->steal
= cputime64_add(cpustat
->steal
, cputime64
);
3416 * Account for idle time.
3417 * @cputime: the cpu time spent in idle wait
3419 void account_idle_time(cputime_t cputime
)
3421 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3422 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
3423 struct rq
*rq
= this_rq();
3425 if (atomic_read(&rq
->nr_iowait
) > 0)
3426 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, cputime64
);
3428 cpustat
->idle
= cputime64_add(cpustat
->idle
, cputime64
);
3431 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
3434 * Account a single tick of cpu time.
3435 * @p: the process that the cpu time gets accounted to
3436 * @user_tick: indicates if the tick is a user or a system tick
3438 void account_process_tick(struct task_struct
*p
, int user_tick
)
3440 cputime_t one_jiffy_scaled
= cputime_to_scaled(cputime_one_jiffy
);
3441 struct rq
*rq
= this_rq();
3444 account_user_time(p
, cputime_one_jiffy
, one_jiffy_scaled
);
3445 else if ((p
!= rq
->idle
) || (irq_count() != HARDIRQ_OFFSET
))
3446 account_system_time(p
, HARDIRQ_OFFSET
, cputime_one_jiffy
,
3449 account_idle_time(cputime_one_jiffy
);
3453 * Account multiple ticks of steal time.
3454 * @p: the process from which the cpu time has been stolen
3455 * @ticks: number of stolen ticks
3457 void account_steal_ticks(unsigned long ticks
)
3459 account_steal_time(jiffies_to_cputime(ticks
));
3463 * Account multiple ticks of idle time.
3464 * @ticks: number of stolen ticks
3466 void account_idle_ticks(unsigned long ticks
)
3468 account_idle_time(jiffies_to_cputime(ticks
));
3474 * Use precise platform statistics if available:
3476 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
3477 void task_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
3483 void thread_group_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
3485 struct task_cputime cputime
;
3487 thread_group_cputime(p
, &cputime
);
3489 *ut
= cputime
.utime
;
3490 *st
= cputime
.stime
;
3494 #ifndef nsecs_to_cputime
3495 # define nsecs_to_cputime(__nsecs) nsecs_to_jiffies(__nsecs)
3498 void task_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
3500 cputime_t rtime
, utime
= p
->utime
, total
= cputime_add(utime
, p
->stime
);
3503 * Use CFS's precise accounting:
3505 rtime
= nsecs_to_cputime(p
->se
.sum_exec_runtime
);
3510 temp
= (u64
)(rtime
* utime
);
3511 do_div(temp
, total
);
3512 utime
= (cputime_t
)temp
;
3517 * Compare with previous values, to keep monotonicity:
3519 p
->prev_utime
= max(p
->prev_utime
, utime
);
3520 p
->prev_stime
= max(p
->prev_stime
, cputime_sub(rtime
, p
->prev_utime
));
3522 *ut
= p
->prev_utime
;
3523 *st
= p
->prev_stime
;
3527 * Must be called with siglock held.
3529 void thread_group_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
3531 struct signal_struct
*sig
= p
->signal
;
3532 struct task_cputime cputime
;
3533 cputime_t rtime
, utime
, total
;
3535 thread_group_cputime(p
, &cputime
);
3537 total
= cputime_add(cputime
.utime
, cputime
.stime
);
3538 rtime
= nsecs_to_cputime(cputime
.sum_exec_runtime
);
3543 temp
= (u64
)(rtime
* cputime
.utime
);
3544 do_div(temp
, total
);
3545 utime
= (cputime_t
)temp
;
3549 sig
->prev_utime
= max(sig
->prev_utime
, utime
);
3550 sig
->prev_stime
= max(sig
->prev_stime
,
3551 cputime_sub(rtime
, sig
->prev_utime
));
3553 *ut
= sig
->prev_utime
;
3554 *st
= sig
->prev_stime
;
3559 * This function gets called by the timer code, with HZ frequency.
3560 * We call it with interrupts disabled.
3562 * It also gets called by the fork code, when changing the parent's
3565 void scheduler_tick(void)
3567 int cpu
= smp_processor_id();
3568 struct rq
*rq
= cpu_rq(cpu
);
3569 struct task_struct
*curr
= rq
->curr
;
3573 raw_spin_lock(&rq
->lock
);
3574 update_rq_clock(rq
);
3575 update_cpu_load_active(rq
);
3576 curr
->sched_class
->task_tick(rq
, curr
, 0);
3577 raw_spin_unlock(&rq
->lock
);
3579 perf_event_task_tick(curr
);
3582 rq
->idle_at_tick
= idle_cpu(cpu
);
3583 trigger_load_balance(rq
, cpu
);
3587 notrace
unsigned long get_parent_ip(unsigned long addr
)
3589 if (in_lock_functions(addr
)) {
3590 addr
= CALLER_ADDR2
;
3591 if (in_lock_functions(addr
))
3592 addr
= CALLER_ADDR3
;
3597 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
3598 defined(CONFIG_PREEMPT_TRACER))
3600 void __kprobes
add_preempt_count(int val
)
3602 #ifdef CONFIG_DEBUG_PREEMPT
3606 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
3609 preempt_count() += val
;
3610 #ifdef CONFIG_DEBUG_PREEMPT
3612 * Spinlock count overflowing soon?
3614 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
3617 if (preempt_count() == val
)
3618 trace_preempt_off(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
3620 EXPORT_SYMBOL(add_preempt_count
);
3622 void __kprobes
sub_preempt_count(int val
)
3624 #ifdef CONFIG_DEBUG_PREEMPT
3628 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
3631 * Is the spinlock portion underflowing?
3633 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
3634 !(preempt_count() & PREEMPT_MASK
)))
3638 if (preempt_count() == val
)
3639 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
3640 preempt_count() -= val
;
3642 EXPORT_SYMBOL(sub_preempt_count
);
3647 * Print scheduling while atomic bug:
3649 static noinline
void __schedule_bug(struct task_struct
*prev
)
3651 struct pt_regs
*regs
= get_irq_regs();
3653 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
3654 prev
->comm
, prev
->pid
, preempt_count());
3656 debug_show_held_locks(prev
);
3658 if (irqs_disabled())
3659 print_irqtrace_events(prev
);
3668 * Various schedule()-time debugging checks and statistics:
3670 static inline void schedule_debug(struct task_struct
*prev
)
3673 * Test if we are atomic. Since do_exit() needs to call into
3674 * schedule() atomically, we ignore that path for now.
3675 * Otherwise, whine if we are scheduling when we should not be.
3677 if (unlikely(in_atomic_preempt_off() && !prev
->exit_state
))
3678 __schedule_bug(prev
);
3680 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
3682 schedstat_inc(this_rq(), sched_count
);
3683 #ifdef CONFIG_SCHEDSTATS
3684 if (unlikely(prev
->lock_depth
>= 0)) {
3685 schedstat_inc(this_rq(), bkl_count
);
3686 schedstat_inc(prev
, sched_info
.bkl_count
);
3691 static void put_prev_task(struct rq
*rq
, struct task_struct
*prev
)
3694 update_rq_clock(rq
);
3695 rq
->skip_clock_update
= 0;
3696 prev
->sched_class
->put_prev_task(rq
, prev
);
3700 * Pick up the highest-prio task:
3702 static inline struct task_struct
*
3703 pick_next_task(struct rq
*rq
)
3705 const struct sched_class
*class;
3706 struct task_struct
*p
;
3709 * Optimization: we know that if all tasks are in
3710 * the fair class we can call that function directly:
3712 if (likely(rq
->nr_running
== rq
->cfs
.nr_running
)) {
3713 p
= fair_sched_class
.pick_next_task(rq
);
3718 class = sched_class_highest
;
3720 p
= class->pick_next_task(rq
);
3724 * Will never be NULL as the idle class always
3725 * returns a non-NULL p:
3727 class = class->next
;
3732 * schedule() is the main scheduler function.
3734 asmlinkage
void __sched
schedule(void)
3736 struct task_struct
*prev
, *next
;
3737 unsigned long *switch_count
;
3743 cpu
= smp_processor_id();
3745 rcu_note_context_switch(cpu
);
3748 release_kernel_lock(prev
);
3749 need_resched_nonpreemptible
:
3751 schedule_debug(prev
);
3753 if (sched_feat(HRTICK
))
3756 raw_spin_lock_irq(&rq
->lock
);
3757 clear_tsk_need_resched(prev
);
3759 switch_count
= &prev
->nivcsw
;
3760 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
3761 if (unlikely(signal_pending_state(prev
->state
, prev
))) {
3762 prev
->state
= TASK_RUNNING
;
3765 * If a worker is going to sleep, notify and
3766 * ask workqueue whether it wants to wake up a
3767 * task to maintain concurrency. If so, wake
3770 if (prev
->flags
& PF_WQ_WORKER
) {
3771 struct task_struct
*to_wakeup
;
3773 to_wakeup
= wq_worker_sleeping(prev
, cpu
);
3775 try_to_wake_up_local(to_wakeup
);
3777 deactivate_task(rq
, prev
, DEQUEUE_SLEEP
);
3779 switch_count
= &prev
->nvcsw
;
3782 pre_schedule(rq
, prev
);
3784 if (unlikely(!rq
->nr_running
))
3785 idle_balance(cpu
, rq
);
3787 put_prev_task(rq
, prev
);
3788 next
= pick_next_task(rq
);
3790 if (likely(prev
!= next
)) {
3791 sched_info_switch(prev
, next
);
3792 perf_event_task_sched_out(prev
, next
);
3798 context_switch(rq
, prev
, next
); /* unlocks the rq */
3800 * The context switch have flipped the stack from under us
3801 * and restored the local variables which were saved when
3802 * this task called schedule() in the past. prev == current
3803 * is still correct, but it can be moved to another cpu/rq.
3805 cpu
= smp_processor_id();
3808 raw_spin_unlock_irq(&rq
->lock
);
3812 if (unlikely(reacquire_kernel_lock(prev
)))
3813 goto need_resched_nonpreemptible
;
3815 preempt_enable_no_resched();
3819 EXPORT_SYMBOL(schedule
);
3821 #ifdef CONFIG_MUTEX_SPIN_ON_OWNER
3823 * Look out! "owner" is an entirely speculative pointer
3824 * access and not reliable.
3826 int mutex_spin_on_owner(struct mutex
*lock
, struct thread_info
*owner
)
3831 if (!sched_feat(OWNER_SPIN
))
3834 #ifdef CONFIG_DEBUG_PAGEALLOC
3836 * Need to access the cpu field knowing that
3837 * DEBUG_PAGEALLOC could have unmapped it if
3838 * the mutex owner just released it and exited.
3840 if (probe_kernel_address(&owner
->cpu
, cpu
))
3847 * Even if the access succeeded (likely case),
3848 * the cpu field may no longer be valid.
3850 if (cpu
>= nr_cpumask_bits
)
3854 * We need to validate that we can do a
3855 * get_cpu() and that we have the percpu area.
3857 if (!cpu_online(cpu
))
3864 * Owner changed, break to re-assess state.
3866 if (lock
->owner
!= owner
)
3870 * Is that owner really running on that cpu?
3872 if (task_thread_info(rq
->curr
) != owner
|| need_resched())
3882 #ifdef CONFIG_PREEMPT
3884 * this is the entry point to schedule() from in-kernel preemption
3885 * off of preempt_enable. Kernel preemptions off return from interrupt
3886 * occur there and call schedule directly.
3888 asmlinkage
void __sched
preempt_schedule(void)
3890 struct thread_info
*ti
= current_thread_info();
3893 * If there is a non-zero preempt_count or interrupts are disabled,
3894 * we do not want to preempt the current task. Just return..
3896 if (likely(ti
->preempt_count
|| irqs_disabled()))
3900 add_preempt_count(PREEMPT_ACTIVE
);
3902 sub_preempt_count(PREEMPT_ACTIVE
);
3905 * Check again in case we missed a preemption opportunity
3906 * between schedule and now.
3909 } while (need_resched());
3911 EXPORT_SYMBOL(preempt_schedule
);
3914 * this is the entry point to schedule() from kernel preemption
3915 * off of irq context.
3916 * Note, that this is called and return with irqs disabled. This will
3917 * protect us against recursive calling from irq.
3919 asmlinkage
void __sched
preempt_schedule_irq(void)
3921 struct thread_info
*ti
= current_thread_info();
3923 /* Catch callers which need to be fixed */
3924 BUG_ON(ti
->preempt_count
|| !irqs_disabled());
3927 add_preempt_count(PREEMPT_ACTIVE
);
3930 local_irq_disable();
3931 sub_preempt_count(PREEMPT_ACTIVE
);
3934 * Check again in case we missed a preemption opportunity
3935 * between schedule and now.
3938 } while (need_resched());
3941 #endif /* CONFIG_PREEMPT */
3943 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int wake_flags
,
3946 return try_to_wake_up(curr
->private, mode
, wake_flags
);
3948 EXPORT_SYMBOL(default_wake_function
);
3951 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
3952 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
3953 * number) then we wake all the non-exclusive tasks and one exclusive task.
3955 * There are circumstances in which we can try to wake a task which has already
3956 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
3957 * zero in this (rare) case, and we handle it by continuing to scan the queue.
3959 static void __wake_up_common(wait_queue_head_t
*q
, unsigned int mode
,
3960 int nr_exclusive
, int wake_flags
, void *key
)
3962 wait_queue_t
*curr
, *next
;
3964 list_for_each_entry_safe(curr
, next
, &q
->task_list
, task_list
) {
3965 unsigned flags
= curr
->flags
;
3967 if (curr
->func(curr
, mode
, wake_flags
, key
) &&
3968 (flags
& WQ_FLAG_EXCLUSIVE
) && !--nr_exclusive
)
3974 * __wake_up - wake up threads blocked on a waitqueue.
3976 * @mode: which threads
3977 * @nr_exclusive: how many wake-one or wake-many threads to wake up
3978 * @key: is directly passed to the wakeup function
3980 * It may be assumed that this function implies a write memory barrier before
3981 * changing the task state if and only if any tasks are woken up.
3983 void __wake_up(wait_queue_head_t
*q
, unsigned int mode
,
3984 int nr_exclusive
, void *key
)
3986 unsigned long flags
;
3988 spin_lock_irqsave(&q
->lock
, flags
);
3989 __wake_up_common(q
, mode
, nr_exclusive
, 0, key
);
3990 spin_unlock_irqrestore(&q
->lock
, flags
);
3992 EXPORT_SYMBOL(__wake_up
);
3995 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
3997 void __wake_up_locked(wait_queue_head_t
*q
, unsigned int mode
)
3999 __wake_up_common(q
, mode
, 1, 0, NULL
);
4001 EXPORT_SYMBOL_GPL(__wake_up_locked
);
4003 void __wake_up_locked_key(wait_queue_head_t
*q
, unsigned int mode
, void *key
)
4005 __wake_up_common(q
, mode
, 1, 0, key
);
4009 * __wake_up_sync_key - wake up threads blocked on a waitqueue.
4011 * @mode: which threads
4012 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4013 * @key: opaque value to be passed to wakeup targets
4015 * The sync wakeup differs that the waker knows that it will schedule
4016 * away soon, so while the target thread will be woken up, it will not
4017 * be migrated to another CPU - ie. the two threads are 'synchronized'
4018 * with each other. This can prevent needless bouncing between CPUs.
4020 * On UP it can prevent extra preemption.
4022 * It may be assumed that this function implies a write memory barrier before
4023 * changing the task state if and only if any tasks are woken up.
4025 void __wake_up_sync_key(wait_queue_head_t
*q
, unsigned int mode
,
4026 int nr_exclusive
, void *key
)
4028 unsigned long flags
;
4029 int wake_flags
= WF_SYNC
;
4034 if (unlikely(!nr_exclusive
))
4037 spin_lock_irqsave(&q
->lock
, flags
);
4038 __wake_up_common(q
, mode
, nr_exclusive
, wake_flags
, key
);
4039 spin_unlock_irqrestore(&q
->lock
, flags
);
4041 EXPORT_SYMBOL_GPL(__wake_up_sync_key
);
4044 * __wake_up_sync - see __wake_up_sync_key()
4046 void __wake_up_sync(wait_queue_head_t
*q
, unsigned int mode
, int nr_exclusive
)
4048 __wake_up_sync_key(q
, mode
, nr_exclusive
, NULL
);
4050 EXPORT_SYMBOL_GPL(__wake_up_sync
); /* For internal use only */
4053 * complete: - signals a single thread waiting on this completion
4054 * @x: holds the state of this particular completion
4056 * This will wake up a single thread waiting on this completion. Threads will be
4057 * awakened in the same order in which they were queued.
4059 * See also complete_all(), wait_for_completion() and related routines.
4061 * It may be assumed that this function implies a write memory barrier before
4062 * changing the task state if and only if any tasks are woken up.
4064 void complete(struct completion
*x
)
4066 unsigned long flags
;
4068 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4070 __wake_up_common(&x
->wait
, TASK_NORMAL
, 1, 0, NULL
);
4071 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4073 EXPORT_SYMBOL(complete
);
4076 * complete_all: - signals all threads waiting on this completion
4077 * @x: holds the state of this particular completion
4079 * This will wake up all threads waiting on this particular completion event.
4081 * It may be assumed that this function implies a write memory barrier before
4082 * changing the task state if and only if any tasks are woken up.
4084 void complete_all(struct completion
*x
)
4086 unsigned long flags
;
4088 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4089 x
->done
+= UINT_MAX
/2;
4090 __wake_up_common(&x
->wait
, TASK_NORMAL
, 0, 0, NULL
);
4091 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4093 EXPORT_SYMBOL(complete_all
);
4095 static inline long __sched
4096 do_wait_for_common(struct completion
*x
, long timeout
, int state
)
4099 DECLARE_WAITQUEUE(wait
, current
);
4101 __add_wait_queue_tail_exclusive(&x
->wait
, &wait
);
4103 if (signal_pending_state(state
, current
)) {
4104 timeout
= -ERESTARTSYS
;
4107 __set_current_state(state
);
4108 spin_unlock_irq(&x
->wait
.lock
);
4109 timeout
= schedule_timeout(timeout
);
4110 spin_lock_irq(&x
->wait
.lock
);
4111 } while (!x
->done
&& timeout
);
4112 __remove_wait_queue(&x
->wait
, &wait
);
4117 return timeout
?: 1;
4121 wait_for_common(struct completion
*x
, long timeout
, int state
)
4125 spin_lock_irq(&x
->wait
.lock
);
4126 timeout
= do_wait_for_common(x
, timeout
, state
);
4127 spin_unlock_irq(&x
->wait
.lock
);
4132 * wait_for_completion: - waits for completion of a task
4133 * @x: holds the state of this particular completion
4135 * This waits to be signaled for completion of a specific task. It is NOT
4136 * interruptible and there is no timeout.
4138 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
4139 * and interrupt capability. Also see complete().
4141 void __sched
wait_for_completion(struct completion
*x
)
4143 wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
4145 EXPORT_SYMBOL(wait_for_completion
);
4148 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
4149 * @x: holds the state of this particular completion
4150 * @timeout: timeout value in jiffies
4152 * This waits for either a completion of a specific task to be signaled or for a
4153 * specified timeout to expire. The timeout is in jiffies. It is not
4156 unsigned long __sched
4157 wait_for_completion_timeout(struct completion
*x
, unsigned long timeout
)
4159 return wait_for_common(x
, timeout
, TASK_UNINTERRUPTIBLE
);
4161 EXPORT_SYMBOL(wait_for_completion_timeout
);
4164 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
4165 * @x: holds the state of this particular completion
4167 * This waits for completion of a specific task to be signaled. It is
4170 int __sched
wait_for_completion_interruptible(struct completion
*x
)
4172 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_INTERRUPTIBLE
);
4173 if (t
== -ERESTARTSYS
)
4177 EXPORT_SYMBOL(wait_for_completion_interruptible
);
4180 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
4181 * @x: holds the state of this particular completion
4182 * @timeout: timeout value in jiffies
4184 * This waits for either a completion of a specific task to be signaled or for a
4185 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
4187 unsigned long __sched
4188 wait_for_completion_interruptible_timeout(struct completion
*x
,
4189 unsigned long timeout
)
4191 return wait_for_common(x
, timeout
, TASK_INTERRUPTIBLE
);
4193 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout
);
4196 * wait_for_completion_killable: - waits for completion of a task (killable)
4197 * @x: holds the state of this particular completion
4199 * This waits to be signaled for completion of a specific task. It can be
4200 * interrupted by a kill signal.
4202 int __sched
wait_for_completion_killable(struct completion
*x
)
4204 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_KILLABLE
);
4205 if (t
== -ERESTARTSYS
)
4209 EXPORT_SYMBOL(wait_for_completion_killable
);
4212 * wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable))
4213 * @x: holds the state of this particular completion
4214 * @timeout: timeout value in jiffies
4216 * This waits for either a completion of a specific task to be
4217 * signaled or for a specified timeout to expire. It can be
4218 * interrupted by a kill signal. The timeout is in jiffies.
4220 unsigned long __sched
4221 wait_for_completion_killable_timeout(struct completion
*x
,
4222 unsigned long timeout
)
4224 return wait_for_common(x
, timeout
, TASK_KILLABLE
);
4226 EXPORT_SYMBOL(wait_for_completion_killable_timeout
);
4229 * try_wait_for_completion - try to decrement a completion without blocking
4230 * @x: completion structure
4232 * Returns: 0 if a decrement cannot be done without blocking
4233 * 1 if a decrement succeeded.
4235 * If a completion is being used as a counting completion,
4236 * attempt to decrement the counter without blocking. This
4237 * enables us to avoid waiting if the resource the completion
4238 * is protecting is not available.
4240 bool try_wait_for_completion(struct completion
*x
)
4242 unsigned long flags
;
4245 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4250 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4253 EXPORT_SYMBOL(try_wait_for_completion
);
4256 * completion_done - Test to see if a completion has any waiters
4257 * @x: completion structure
4259 * Returns: 0 if there are waiters (wait_for_completion() in progress)
4260 * 1 if there are no waiters.
4263 bool completion_done(struct completion
*x
)
4265 unsigned long flags
;
4268 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4271 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4274 EXPORT_SYMBOL(completion_done
);
4277 sleep_on_common(wait_queue_head_t
*q
, int state
, long timeout
)
4279 unsigned long flags
;
4282 init_waitqueue_entry(&wait
, current
);
4284 __set_current_state(state
);
4286 spin_lock_irqsave(&q
->lock
, flags
);
4287 __add_wait_queue(q
, &wait
);
4288 spin_unlock(&q
->lock
);
4289 timeout
= schedule_timeout(timeout
);
4290 spin_lock_irq(&q
->lock
);
4291 __remove_wait_queue(q
, &wait
);
4292 spin_unlock_irqrestore(&q
->lock
, flags
);
4297 void __sched
interruptible_sleep_on(wait_queue_head_t
*q
)
4299 sleep_on_common(q
, TASK_INTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
4301 EXPORT_SYMBOL(interruptible_sleep_on
);
4304 interruptible_sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
4306 return sleep_on_common(q
, TASK_INTERRUPTIBLE
, timeout
);
4308 EXPORT_SYMBOL(interruptible_sleep_on_timeout
);
4310 void __sched
sleep_on(wait_queue_head_t
*q
)
4312 sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
4314 EXPORT_SYMBOL(sleep_on
);
4316 long __sched
sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
4318 return sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, timeout
);
4320 EXPORT_SYMBOL(sleep_on_timeout
);
4322 #ifdef CONFIG_RT_MUTEXES
4325 * rt_mutex_setprio - set the current priority of a task
4327 * @prio: prio value (kernel-internal form)
4329 * This function changes the 'effective' priority of a task. It does
4330 * not touch ->normal_prio like __setscheduler().
4332 * Used by the rt_mutex code to implement priority inheritance logic.
4334 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
4336 unsigned long flags
;
4337 int oldprio
, on_rq
, running
;
4339 const struct sched_class
*prev_class
;
4341 BUG_ON(prio
< 0 || prio
> MAX_PRIO
);
4343 rq
= task_rq_lock(p
, &flags
);
4346 prev_class
= p
->sched_class
;
4347 on_rq
= p
->se
.on_rq
;
4348 running
= task_current(rq
, p
);
4350 dequeue_task(rq
, p
, 0);
4352 p
->sched_class
->put_prev_task(rq
, p
);
4355 p
->sched_class
= &rt_sched_class
;
4357 p
->sched_class
= &fair_sched_class
;
4362 p
->sched_class
->set_curr_task(rq
);
4364 enqueue_task(rq
, p
, oldprio
< prio
? ENQUEUE_HEAD
: 0);
4366 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
4368 task_rq_unlock(rq
, &flags
);
4373 void set_user_nice(struct task_struct
*p
, long nice
)
4375 int old_prio
, delta
, on_rq
;
4376 unsigned long flags
;
4379 if (TASK_NICE(p
) == nice
|| nice
< -20 || nice
> 19)
4382 * We have to be careful, if called from sys_setpriority(),
4383 * the task might be in the middle of scheduling on another CPU.
4385 rq
= task_rq_lock(p
, &flags
);
4387 * The RT priorities are set via sched_setscheduler(), but we still
4388 * allow the 'normal' nice value to be set - but as expected
4389 * it wont have any effect on scheduling until the task is
4390 * SCHED_FIFO/SCHED_RR:
4392 if (task_has_rt_policy(p
)) {
4393 p
->static_prio
= NICE_TO_PRIO(nice
);
4396 on_rq
= p
->se
.on_rq
;
4398 dequeue_task(rq
, p
, 0);
4400 p
->static_prio
= NICE_TO_PRIO(nice
);
4403 p
->prio
= effective_prio(p
);
4404 delta
= p
->prio
- old_prio
;
4407 enqueue_task(rq
, p
, 0);
4409 * If the task increased its priority or is running and
4410 * lowered its priority, then reschedule its CPU:
4412 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
4413 resched_task(rq
->curr
);
4416 task_rq_unlock(rq
, &flags
);
4418 EXPORT_SYMBOL(set_user_nice
);
4421 * can_nice - check if a task can reduce its nice value
4425 int can_nice(const struct task_struct
*p
, const int nice
)
4427 /* convert nice value [19,-20] to rlimit style value [1,40] */
4428 int nice_rlim
= 20 - nice
;
4430 return (nice_rlim
<= task_rlimit(p
, RLIMIT_NICE
) ||
4431 capable(CAP_SYS_NICE
));
4434 #ifdef __ARCH_WANT_SYS_NICE
4437 * sys_nice - change the priority of the current process.
4438 * @increment: priority increment
4440 * sys_setpriority is a more generic, but much slower function that
4441 * does similar things.
4443 SYSCALL_DEFINE1(nice
, int, increment
)
4448 * Setpriority might change our priority at the same moment.
4449 * We don't have to worry. Conceptually one call occurs first
4450 * and we have a single winner.
4452 if (increment
< -40)
4457 nice
= TASK_NICE(current
) + increment
;
4463 if (increment
< 0 && !can_nice(current
, nice
))
4466 retval
= security_task_setnice(current
, nice
);
4470 set_user_nice(current
, nice
);
4477 * task_prio - return the priority value of a given task.
4478 * @p: the task in question.
4480 * This is the priority value as seen by users in /proc.
4481 * RT tasks are offset by -200. Normal tasks are centered
4482 * around 0, value goes from -16 to +15.
4484 int task_prio(const struct task_struct
*p
)
4486 return p
->prio
- MAX_RT_PRIO
;
4490 * task_nice - return the nice value of a given task.
4491 * @p: the task in question.
4493 int task_nice(const struct task_struct
*p
)
4495 return TASK_NICE(p
);
4497 EXPORT_SYMBOL(task_nice
);
4500 * idle_cpu - is a given cpu idle currently?
4501 * @cpu: the processor in question.
4503 int idle_cpu(int cpu
)
4505 return cpu_curr(cpu
) == cpu_rq(cpu
)->idle
;
4509 * idle_task - return the idle task for a given cpu.
4510 * @cpu: the processor in question.
4512 struct task_struct
*idle_task(int cpu
)
4514 return cpu_rq(cpu
)->idle
;
4518 * find_process_by_pid - find a process with a matching PID value.
4519 * @pid: the pid in question.
4521 static struct task_struct
*find_process_by_pid(pid_t pid
)
4523 return pid
? find_task_by_vpid(pid
) : current
;
4526 /* Actually do priority change: must hold rq lock. */
4528 __setscheduler(struct rq
*rq
, struct task_struct
*p
, int policy
, int prio
)
4530 BUG_ON(p
->se
.on_rq
);
4533 p
->rt_priority
= prio
;
4534 p
->normal_prio
= normal_prio(p
);
4535 /* we are holding p->pi_lock already */
4536 p
->prio
= rt_mutex_getprio(p
);
4537 if (rt_prio(p
->prio
))
4538 p
->sched_class
= &rt_sched_class
;
4540 p
->sched_class
= &fair_sched_class
;
4545 * check the target process has a UID that matches the current process's
4547 static bool check_same_owner(struct task_struct
*p
)
4549 const struct cred
*cred
= current_cred(), *pcred
;
4553 pcred
= __task_cred(p
);
4554 match
= (cred
->euid
== pcred
->euid
||
4555 cred
->euid
== pcred
->uid
);
4560 static int __sched_setscheduler(struct task_struct
*p
, int policy
,
4561 struct sched_param
*param
, bool user
)
4563 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
4564 unsigned long flags
;
4565 const struct sched_class
*prev_class
;
4569 /* may grab non-irq protected spin_locks */
4570 BUG_ON(in_interrupt());
4572 /* double check policy once rq lock held */
4574 reset_on_fork
= p
->sched_reset_on_fork
;
4575 policy
= oldpolicy
= p
->policy
;
4577 reset_on_fork
= !!(policy
& SCHED_RESET_ON_FORK
);
4578 policy
&= ~SCHED_RESET_ON_FORK
;
4580 if (policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
4581 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
4582 policy
!= SCHED_IDLE
)
4587 * Valid priorities for SCHED_FIFO and SCHED_RR are
4588 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
4589 * SCHED_BATCH and SCHED_IDLE is 0.
4591 if (param
->sched_priority
< 0 ||
4592 (p
->mm
&& param
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
4593 (!p
->mm
&& param
->sched_priority
> MAX_RT_PRIO
-1))
4595 if (rt_policy(policy
) != (param
->sched_priority
!= 0))
4599 * Allow unprivileged RT tasks to decrease priority:
4601 if (user
&& !capable(CAP_SYS_NICE
)) {
4602 if (rt_policy(policy
)) {
4603 unsigned long rlim_rtprio
=
4604 task_rlimit(p
, RLIMIT_RTPRIO
);
4606 /* can't set/change the rt policy */
4607 if (policy
!= p
->policy
&& !rlim_rtprio
)
4610 /* can't increase priority */
4611 if (param
->sched_priority
> p
->rt_priority
&&
4612 param
->sched_priority
> rlim_rtprio
)
4616 * Like positive nice levels, dont allow tasks to
4617 * move out of SCHED_IDLE either:
4619 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
)
4622 /* can't change other user's priorities */
4623 if (!check_same_owner(p
))
4626 /* Normal users shall not reset the sched_reset_on_fork flag */
4627 if (p
->sched_reset_on_fork
&& !reset_on_fork
)
4632 retval
= security_task_setscheduler(p
, policy
, param
);
4638 * make sure no PI-waiters arrive (or leave) while we are
4639 * changing the priority of the task:
4641 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
4643 * To be able to change p->policy safely, the apropriate
4644 * runqueue lock must be held.
4646 rq
= __task_rq_lock(p
);
4648 #ifdef CONFIG_RT_GROUP_SCHED
4651 * Do not allow realtime tasks into groups that have no runtime
4654 if (rt_bandwidth_enabled() && rt_policy(policy
) &&
4655 task_group(p
)->rt_bandwidth
.rt_runtime
== 0) {
4656 __task_rq_unlock(rq
);
4657 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4663 /* recheck policy now with rq lock held */
4664 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
4665 policy
= oldpolicy
= -1;
4666 __task_rq_unlock(rq
);
4667 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4670 on_rq
= p
->se
.on_rq
;
4671 running
= task_current(rq
, p
);
4673 deactivate_task(rq
, p
, 0);
4675 p
->sched_class
->put_prev_task(rq
, p
);
4677 p
->sched_reset_on_fork
= reset_on_fork
;
4680 prev_class
= p
->sched_class
;
4681 __setscheduler(rq
, p
, policy
, param
->sched_priority
);
4684 p
->sched_class
->set_curr_task(rq
);
4686 activate_task(rq
, p
, 0);
4688 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
4690 __task_rq_unlock(rq
);
4691 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4693 rt_mutex_adjust_pi(p
);
4699 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
4700 * @p: the task in question.
4701 * @policy: new policy.
4702 * @param: structure containing the new RT priority.
4704 * NOTE that the task may be already dead.
4706 int sched_setscheduler(struct task_struct
*p
, int policy
,
4707 struct sched_param
*param
)
4709 return __sched_setscheduler(p
, policy
, param
, true);
4711 EXPORT_SYMBOL_GPL(sched_setscheduler
);
4714 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
4715 * @p: the task in question.
4716 * @policy: new policy.
4717 * @param: structure containing the new RT priority.
4719 * Just like sched_setscheduler, only don't bother checking if the
4720 * current context has permission. For example, this is needed in
4721 * stop_machine(): we create temporary high priority worker threads,
4722 * but our caller might not have that capability.
4724 int sched_setscheduler_nocheck(struct task_struct
*p
, int policy
,
4725 struct sched_param
*param
)
4727 return __sched_setscheduler(p
, policy
, param
, false);
4731 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
4733 struct sched_param lparam
;
4734 struct task_struct
*p
;
4737 if (!param
|| pid
< 0)
4739 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
4744 p
= find_process_by_pid(pid
);
4746 retval
= sched_setscheduler(p
, policy
, &lparam
);
4753 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
4754 * @pid: the pid in question.
4755 * @policy: new policy.
4756 * @param: structure containing the new RT priority.
4758 SYSCALL_DEFINE3(sched_setscheduler
, pid_t
, pid
, int, policy
,
4759 struct sched_param __user
*, param
)
4761 /* negative values for policy are not valid */
4765 return do_sched_setscheduler(pid
, policy
, param
);
4769 * sys_sched_setparam - set/change the RT priority of a thread
4770 * @pid: the pid in question.
4771 * @param: structure containing the new RT priority.
4773 SYSCALL_DEFINE2(sched_setparam
, pid_t
, pid
, struct sched_param __user
*, param
)
4775 return do_sched_setscheduler(pid
, -1, param
);
4779 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
4780 * @pid: the pid in question.
4782 SYSCALL_DEFINE1(sched_getscheduler
, pid_t
, pid
)
4784 struct task_struct
*p
;
4792 p
= find_process_by_pid(pid
);
4794 retval
= security_task_getscheduler(p
);
4797 | (p
->sched_reset_on_fork
? SCHED_RESET_ON_FORK
: 0);
4804 * sys_sched_getparam - get the RT priority of a thread
4805 * @pid: the pid in question.
4806 * @param: structure containing the RT priority.
4808 SYSCALL_DEFINE2(sched_getparam
, pid_t
, pid
, struct sched_param __user
*, param
)
4810 struct sched_param lp
;
4811 struct task_struct
*p
;
4814 if (!param
|| pid
< 0)
4818 p
= find_process_by_pid(pid
);
4823 retval
= security_task_getscheduler(p
);
4827 lp
.sched_priority
= p
->rt_priority
;
4831 * This one might sleep, we cannot do it with a spinlock held ...
4833 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
4842 long sched_setaffinity(pid_t pid
, const struct cpumask
*in_mask
)
4844 cpumask_var_t cpus_allowed
, new_mask
;
4845 struct task_struct
*p
;
4851 p
= find_process_by_pid(pid
);
4858 /* Prevent p going away */
4862 if (!alloc_cpumask_var(&cpus_allowed
, GFP_KERNEL
)) {
4866 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
)) {
4868 goto out_free_cpus_allowed
;
4871 if (!check_same_owner(p
) && !capable(CAP_SYS_NICE
))
4874 retval
= security_task_setscheduler(p
, 0, NULL
);
4878 cpuset_cpus_allowed(p
, cpus_allowed
);
4879 cpumask_and(new_mask
, in_mask
, cpus_allowed
);
4881 retval
= set_cpus_allowed_ptr(p
, new_mask
);
4884 cpuset_cpus_allowed(p
, cpus_allowed
);
4885 if (!cpumask_subset(new_mask
, cpus_allowed
)) {
4887 * We must have raced with a concurrent cpuset
4888 * update. Just reset the cpus_allowed to the
4889 * cpuset's cpus_allowed
4891 cpumask_copy(new_mask
, cpus_allowed
);
4896 free_cpumask_var(new_mask
);
4897 out_free_cpus_allowed
:
4898 free_cpumask_var(cpus_allowed
);
4905 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
4906 struct cpumask
*new_mask
)
4908 if (len
< cpumask_size())
4909 cpumask_clear(new_mask
);
4910 else if (len
> cpumask_size())
4911 len
= cpumask_size();
4913 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
4917 * sys_sched_setaffinity - set the cpu affinity of a process
4918 * @pid: pid of the process
4919 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4920 * @user_mask_ptr: user-space pointer to the new cpu mask
4922 SYSCALL_DEFINE3(sched_setaffinity
, pid_t
, pid
, unsigned int, len
,
4923 unsigned long __user
*, user_mask_ptr
)
4925 cpumask_var_t new_mask
;
4928 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
4931 retval
= get_user_cpu_mask(user_mask_ptr
, len
, new_mask
);
4933 retval
= sched_setaffinity(pid
, new_mask
);
4934 free_cpumask_var(new_mask
);
4938 long sched_getaffinity(pid_t pid
, struct cpumask
*mask
)
4940 struct task_struct
*p
;
4941 unsigned long flags
;
4949 p
= find_process_by_pid(pid
);
4953 retval
= security_task_getscheduler(p
);
4957 rq
= task_rq_lock(p
, &flags
);
4958 cpumask_and(mask
, &p
->cpus_allowed
, cpu_online_mask
);
4959 task_rq_unlock(rq
, &flags
);
4969 * sys_sched_getaffinity - get the cpu affinity of a process
4970 * @pid: pid of the process
4971 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4972 * @user_mask_ptr: user-space pointer to hold the current cpu mask
4974 SYSCALL_DEFINE3(sched_getaffinity
, pid_t
, pid
, unsigned int, len
,
4975 unsigned long __user
*, user_mask_ptr
)
4980 if ((len
* BITS_PER_BYTE
) < nr_cpu_ids
)
4982 if (len
& (sizeof(unsigned long)-1))
4985 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
4988 ret
= sched_getaffinity(pid
, mask
);
4990 size_t retlen
= min_t(size_t, len
, cpumask_size());
4992 if (copy_to_user(user_mask_ptr
, mask
, retlen
))
4997 free_cpumask_var(mask
);
5003 * sys_sched_yield - yield the current processor to other threads.
5005 * This function yields the current CPU to other tasks. If there are no
5006 * other threads running on this CPU then this function will return.
5008 SYSCALL_DEFINE0(sched_yield
)
5010 struct rq
*rq
= this_rq_lock();
5012 schedstat_inc(rq
, yld_count
);
5013 current
->sched_class
->yield_task(rq
);
5016 * Since we are going to call schedule() anyway, there's
5017 * no need to preempt or enable interrupts:
5019 __release(rq
->lock
);
5020 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
5021 do_raw_spin_unlock(&rq
->lock
);
5022 preempt_enable_no_resched();
5029 static inline int should_resched(void)
5031 return need_resched() && !(preempt_count() & PREEMPT_ACTIVE
);
5034 static void __cond_resched(void)
5036 add_preempt_count(PREEMPT_ACTIVE
);
5038 sub_preempt_count(PREEMPT_ACTIVE
);
5041 int __sched
_cond_resched(void)
5043 if (should_resched()) {
5049 EXPORT_SYMBOL(_cond_resched
);
5052 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
5053 * call schedule, and on return reacquire the lock.
5055 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
5056 * operations here to prevent schedule() from being called twice (once via
5057 * spin_unlock(), once by hand).
5059 int __cond_resched_lock(spinlock_t
*lock
)
5061 int resched
= should_resched();
5064 lockdep_assert_held(lock
);
5066 if (spin_needbreak(lock
) || resched
) {
5077 EXPORT_SYMBOL(__cond_resched_lock
);
5079 int __sched
__cond_resched_softirq(void)
5081 BUG_ON(!in_softirq());
5083 if (should_resched()) {
5091 EXPORT_SYMBOL(__cond_resched_softirq
);
5094 * yield - yield the current processor to other threads.
5096 * This is a shortcut for kernel-space yielding - it marks the
5097 * thread runnable and calls sys_sched_yield().
5099 void __sched
yield(void)
5101 set_current_state(TASK_RUNNING
);
5104 EXPORT_SYMBOL(yield
);
5107 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
5108 * that process accounting knows that this is a task in IO wait state.
5110 void __sched
io_schedule(void)
5112 struct rq
*rq
= raw_rq();
5114 delayacct_blkio_start();
5115 atomic_inc(&rq
->nr_iowait
);
5116 current
->in_iowait
= 1;
5118 current
->in_iowait
= 0;
5119 atomic_dec(&rq
->nr_iowait
);
5120 delayacct_blkio_end();
5122 EXPORT_SYMBOL(io_schedule
);
5124 long __sched
io_schedule_timeout(long timeout
)
5126 struct rq
*rq
= raw_rq();
5129 delayacct_blkio_start();
5130 atomic_inc(&rq
->nr_iowait
);
5131 current
->in_iowait
= 1;
5132 ret
= schedule_timeout(timeout
);
5133 current
->in_iowait
= 0;
5134 atomic_dec(&rq
->nr_iowait
);
5135 delayacct_blkio_end();
5140 * sys_sched_get_priority_max - return maximum RT priority.
5141 * @policy: scheduling class.
5143 * this syscall returns the maximum rt_priority that can be used
5144 * by a given scheduling class.
5146 SYSCALL_DEFINE1(sched_get_priority_max
, int, policy
)
5153 ret
= MAX_USER_RT_PRIO
-1;
5165 * sys_sched_get_priority_min - return minimum RT priority.
5166 * @policy: scheduling class.
5168 * this syscall returns the minimum rt_priority that can be used
5169 * by a given scheduling class.
5171 SYSCALL_DEFINE1(sched_get_priority_min
, int, policy
)
5189 * sys_sched_rr_get_interval - return the default timeslice of a process.
5190 * @pid: pid of the process.
5191 * @interval: userspace pointer to the timeslice value.
5193 * this syscall writes the default timeslice value of a given process
5194 * into the user-space timespec buffer. A value of '0' means infinity.
5196 SYSCALL_DEFINE2(sched_rr_get_interval
, pid_t
, pid
,
5197 struct timespec __user
*, interval
)
5199 struct task_struct
*p
;
5200 unsigned int time_slice
;
5201 unsigned long flags
;
5211 p
= find_process_by_pid(pid
);
5215 retval
= security_task_getscheduler(p
);
5219 rq
= task_rq_lock(p
, &flags
);
5220 time_slice
= p
->sched_class
->get_rr_interval(rq
, p
);
5221 task_rq_unlock(rq
, &flags
);
5224 jiffies_to_timespec(time_slice
, &t
);
5225 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
5233 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
5235 void sched_show_task(struct task_struct
*p
)
5237 unsigned long free
= 0;
5240 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
5241 printk(KERN_INFO
"%-13.13s %c", p
->comm
,
5242 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
5243 #if BITS_PER_LONG == 32
5244 if (state
== TASK_RUNNING
)
5245 printk(KERN_CONT
" running ");
5247 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
5249 if (state
== TASK_RUNNING
)
5250 printk(KERN_CONT
" running task ");
5252 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
5254 #ifdef CONFIG_DEBUG_STACK_USAGE
5255 free
= stack_not_used(p
);
5257 printk(KERN_CONT
"%5lu %5d %6d 0x%08lx\n", free
,
5258 task_pid_nr(p
), task_pid_nr(p
->real_parent
),
5259 (unsigned long)task_thread_info(p
)->flags
);
5261 show_stack(p
, NULL
);
5264 void show_state_filter(unsigned long state_filter
)
5266 struct task_struct
*g
, *p
;
5268 #if BITS_PER_LONG == 32
5270 " task PC stack pid father\n");
5273 " task PC stack pid father\n");
5275 read_lock(&tasklist_lock
);
5276 do_each_thread(g
, p
) {
5278 * reset the NMI-timeout, listing all files on a slow
5279 * console might take alot of time:
5281 touch_nmi_watchdog();
5282 if (!state_filter
|| (p
->state
& state_filter
))
5284 } while_each_thread(g
, p
);
5286 touch_all_softlockup_watchdogs();
5288 #ifdef CONFIG_SCHED_DEBUG
5289 sysrq_sched_debug_show();
5291 read_unlock(&tasklist_lock
);
5293 * Only show locks if all tasks are dumped:
5296 debug_show_all_locks();
5299 void __cpuinit
init_idle_bootup_task(struct task_struct
*idle
)
5301 idle
->sched_class
= &idle_sched_class
;
5305 * init_idle - set up an idle thread for a given CPU
5306 * @idle: task in question
5307 * @cpu: cpu the idle task belongs to
5309 * NOTE: this function does not set the idle thread's NEED_RESCHED
5310 * flag, to make booting more robust.
5312 void __cpuinit
init_idle(struct task_struct
*idle
, int cpu
)
5314 struct rq
*rq
= cpu_rq(cpu
);
5315 unsigned long flags
;
5317 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5320 idle
->state
= TASK_RUNNING
;
5321 idle
->se
.exec_start
= sched_clock();
5323 cpumask_copy(&idle
->cpus_allowed
, cpumask_of(cpu
));
5324 __set_task_cpu(idle
, cpu
);
5326 rq
->curr
= rq
->idle
= idle
;
5327 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
5330 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5332 /* Set the preempt count _outside_ the spinlocks! */
5333 #if defined(CONFIG_PREEMPT)
5334 task_thread_info(idle
)->preempt_count
= (idle
->lock_depth
>= 0);
5336 task_thread_info(idle
)->preempt_count
= 0;
5339 * The idle tasks have their own, simple scheduling class:
5341 idle
->sched_class
= &idle_sched_class
;
5342 ftrace_graph_init_task(idle
);
5346 * In a system that switches off the HZ timer nohz_cpu_mask
5347 * indicates which cpus entered this state. This is used
5348 * in the rcu update to wait only for active cpus. For system
5349 * which do not switch off the HZ timer nohz_cpu_mask should
5350 * always be CPU_BITS_NONE.
5352 cpumask_var_t nohz_cpu_mask
;
5355 * Increase the granularity value when there are more CPUs,
5356 * because with more CPUs the 'effective latency' as visible
5357 * to users decreases. But the relationship is not linear,
5358 * so pick a second-best guess by going with the log2 of the
5361 * This idea comes from the SD scheduler of Con Kolivas:
5363 static int get_update_sysctl_factor(void)
5365 unsigned int cpus
= min_t(int, num_online_cpus(), 8);
5366 unsigned int factor
;
5368 switch (sysctl_sched_tunable_scaling
) {
5369 case SCHED_TUNABLESCALING_NONE
:
5372 case SCHED_TUNABLESCALING_LINEAR
:
5375 case SCHED_TUNABLESCALING_LOG
:
5377 factor
= 1 + ilog2(cpus
);
5384 static void update_sysctl(void)
5386 unsigned int factor
= get_update_sysctl_factor();
5388 #define SET_SYSCTL(name) \
5389 (sysctl_##name = (factor) * normalized_sysctl_##name)
5390 SET_SYSCTL(sched_min_granularity
);
5391 SET_SYSCTL(sched_latency
);
5392 SET_SYSCTL(sched_wakeup_granularity
);
5393 SET_SYSCTL(sched_shares_ratelimit
);
5397 static inline void sched_init_granularity(void)
5404 * This is how migration works:
5406 * 1) we invoke migration_cpu_stop() on the target CPU using
5408 * 2) stopper starts to run (implicitly forcing the migrated thread
5410 * 3) it checks whether the migrated task is still in the wrong runqueue.
5411 * 4) if it's in the wrong runqueue then the migration thread removes
5412 * it and puts it into the right queue.
5413 * 5) stopper completes and stop_one_cpu() returns and the migration
5418 * Change a given task's CPU affinity. Migrate the thread to a
5419 * proper CPU and schedule it away if the CPU it's executing on
5420 * is removed from the allowed bitmask.
5422 * NOTE: the caller must have a valid reference to the task, the
5423 * task must not exit() & deallocate itself prematurely. The
5424 * call is not atomic; no spinlocks may be held.
5426 int set_cpus_allowed_ptr(struct task_struct
*p
, const struct cpumask
*new_mask
)
5428 unsigned long flags
;
5430 unsigned int dest_cpu
;
5434 * Serialize against TASK_WAKING so that ttwu() and wunt() can
5435 * drop the rq->lock and still rely on ->cpus_allowed.
5438 while (task_is_waking(p
))
5440 rq
= task_rq_lock(p
, &flags
);
5441 if (task_is_waking(p
)) {
5442 task_rq_unlock(rq
, &flags
);
5446 if (!cpumask_intersects(new_mask
, cpu_active_mask
)) {
5451 if (unlikely((p
->flags
& PF_THREAD_BOUND
) && p
!= current
&&
5452 !cpumask_equal(&p
->cpus_allowed
, new_mask
))) {
5457 if (p
->sched_class
->set_cpus_allowed
)
5458 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
5460 cpumask_copy(&p
->cpus_allowed
, new_mask
);
5461 p
->rt
.nr_cpus_allowed
= cpumask_weight(new_mask
);
5464 /* Can the task run on the task's current CPU? If so, we're done */
5465 if (cpumask_test_cpu(task_cpu(p
), new_mask
))
5468 dest_cpu
= cpumask_any_and(cpu_active_mask
, new_mask
);
5469 if (migrate_task(p
, dest_cpu
)) {
5470 struct migration_arg arg
= { p
, dest_cpu
};
5471 /* Need help from migration thread: drop lock and wait. */
5472 task_rq_unlock(rq
, &flags
);
5473 stop_one_cpu(cpu_of(rq
), migration_cpu_stop
, &arg
);
5474 tlb_migrate_finish(p
->mm
);
5478 task_rq_unlock(rq
, &flags
);
5482 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
5485 * Move (not current) task off this cpu, onto dest cpu. We're doing
5486 * this because either it can't run here any more (set_cpus_allowed()
5487 * away from this CPU, or CPU going down), or because we're
5488 * attempting to rebalance this task on exec (sched_exec).
5490 * So we race with normal scheduler movements, but that's OK, as long
5491 * as the task is no longer on this CPU.
5493 * Returns non-zero if task was successfully migrated.
5495 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
5497 struct rq
*rq_dest
, *rq_src
;
5500 if (unlikely(!cpu_active(dest_cpu
)))
5503 rq_src
= cpu_rq(src_cpu
);
5504 rq_dest
= cpu_rq(dest_cpu
);
5506 double_rq_lock(rq_src
, rq_dest
);
5507 /* Already moved. */
5508 if (task_cpu(p
) != src_cpu
)
5510 /* Affinity changed (again). */
5511 if (!cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
5515 * If we're not on a rq, the next wake-up will ensure we're
5519 deactivate_task(rq_src
, p
, 0);
5520 set_task_cpu(p
, dest_cpu
);
5521 activate_task(rq_dest
, p
, 0);
5522 check_preempt_curr(rq_dest
, p
, 0);
5527 double_rq_unlock(rq_src
, rq_dest
);
5532 * migration_cpu_stop - this will be executed by a highprio stopper thread
5533 * and performs thread migration by bumping thread off CPU then
5534 * 'pushing' onto another runqueue.
5536 static int migration_cpu_stop(void *data
)
5538 struct migration_arg
*arg
= data
;
5541 * The original target cpu might have gone down and we might
5542 * be on another cpu but it doesn't matter.
5544 local_irq_disable();
5545 __migrate_task(arg
->task
, raw_smp_processor_id(), arg
->dest_cpu
);
5550 #ifdef CONFIG_HOTPLUG_CPU
5552 * Figure out where task on dead CPU should go, use force if necessary.
5554 void move_task_off_dead_cpu(int dead_cpu
, struct task_struct
*p
)
5556 struct rq
*rq
= cpu_rq(dead_cpu
);
5557 int needs_cpu
, uninitialized_var(dest_cpu
);
5558 unsigned long flags
;
5560 local_irq_save(flags
);
5562 raw_spin_lock(&rq
->lock
);
5563 needs_cpu
= (task_cpu(p
) == dead_cpu
) && (p
->state
!= TASK_WAKING
);
5565 dest_cpu
= select_fallback_rq(dead_cpu
, p
);
5566 raw_spin_unlock(&rq
->lock
);
5568 * It can only fail if we race with set_cpus_allowed(),
5569 * in the racer should migrate the task anyway.
5572 __migrate_task(p
, dead_cpu
, dest_cpu
);
5573 local_irq_restore(flags
);
5577 * While a dead CPU has no uninterruptible tasks queued at this point,
5578 * it might still have a nonzero ->nr_uninterruptible counter, because
5579 * for performance reasons the counter is not stricly tracking tasks to
5580 * their home CPUs. So we just add the counter to another CPU's counter,
5581 * to keep the global sum constant after CPU-down:
5583 static void migrate_nr_uninterruptible(struct rq
*rq_src
)
5585 struct rq
*rq_dest
= cpu_rq(cpumask_any(cpu_active_mask
));
5586 unsigned long flags
;
5588 local_irq_save(flags
);
5589 double_rq_lock(rq_src
, rq_dest
);
5590 rq_dest
->nr_uninterruptible
+= rq_src
->nr_uninterruptible
;
5591 rq_src
->nr_uninterruptible
= 0;
5592 double_rq_unlock(rq_src
, rq_dest
);
5593 local_irq_restore(flags
);
5596 /* Run through task list and migrate tasks from the dead cpu. */
5597 static void migrate_live_tasks(int src_cpu
)
5599 struct task_struct
*p
, *t
;
5601 read_lock(&tasklist_lock
);
5603 do_each_thread(t
, p
) {
5607 if (task_cpu(p
) == src_cpu
)
5608 move_task_off_dead_cpu(src_cpu
, p
);
5609 } while_each_thread(t
, p
);
5611 read_unlock(&tasklist_lock
);
5615 * Schedules idle task to be the next runnable task on current CPU.
5616 * It does so by boosting its priority to highest possible.
5617 * Used by CPU offline code.
5619 void sched_idle_next(void)
5621 int this_cpu
= smp_processor_id();
5622 struct rq
*rq
= cpu_rq(this_cpu
);
5623 struct task_struct
*p
= rq
->idle
;
5624 unsigned long flags
;
5626 /* cpu has to be offline */
5627 BUG_ON(cpu_online(this_cpu
));
5630 * Strictly not necessary since rest of the CPUs are stopped by now
5631 * and interrupts disabled on the current cpu.
5633 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5635 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
5637 activate_task(rq
, p
, 0);
5639 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5643 * Ensures that the idle task is using init_mm right before its cpu goes
5646 void idle_task_exit(void)
5648 struct mm_struct
*mm
= current
->active_mm
;
5650 BUG_ON(cpu_online(smp_processor_id()));
5653 switch_mm(mm
, &init_mm
, current
);
5657 /* called under rq->lock with disabled interrupts */
5658 static void migrate_dead(unsigned int dead_cpu
, struct task_struct
*p
)
5660 struct rq
*rq
= cpu_rq(dead_cpu
);
5662 /* Must be exiting, otherwise would be on tasklist. */
5663 BUG_ON(!p
->exit_state
);
5665 /* Cannot have done final schedule yet: would have vanished. */
5666 BUG_ON(p
->state
== TASK_DEAD
);
5671 * Drop lock around migration; if someone else moves it,
5672 * that's OK. No task can be added to this CPU, so iteration is
5675 raw_spin_unlock_irq(&rq
->lock
);
5676 move_task_off_dead_cpu(dead_cpu
, p
);
5677 raw_spin_lock_irq(&rq
->lock
);
5682 /* release_task() removes task from tasklist, so we won't find dead tasks. */
5683 static void migrate_dead_tasks(unsigned int dead_cpu
)
5685 struct rq
*rq
= cpu_rq(dead_cpu
);
5686 struct task_struct
*next
;
5689 if (!rq
->nr_running
)
5691 next
= pick_next_task(rq
);
5694 next
->sched_class
->put_prev_task(rq
, next
);
5695 migrate_dead(dead_cpu
, next
);
5701 * remove the tasks which were accounted by rq from calc_load_tasks.
5703 static void calc_global_load_remove(struct rq
*rq
)
5705 atomic_long_sub(rq
->calc_load_active
, &calc_load_tasks
);
5706 rq
->calc_load_active
= 0;
5708 #endif /* CONFIG_HOTPLUG_CPU */
5710 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
5712 static struct ctl_table sd_ctl_dir
[] = {
5714 .procname
= "sched_domain",
5720 static struct ctl_table sd_ctl_root
[] = {
5722 .procname
= "kernel",
5724 .child
= sd_ctl_dir
,
5729 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
5731 struct ctl_table
*entry
=
5732 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
5737 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
5739 struct ctl_table
*entry
;
5742 * In the intermediate directories, both the child directory and
5743 * procname are dynamically allocated and could fail but the mode
5744 * will always be set. In the lowest directory the names are
5745 * static strings and all have proc handlers.
5747 for (entry
= *tablep
; entry
->mode
; entry
++) {
5749 sd_free_ctl_entry(&entry
->child
);
5750 if (entry
->proc_handler
== NULL
)
5751 kfree(entry
->procname
);
5759 set_table_entry(struct ctl_table
*entry
,
5760 const char *procname
, void *data
, int maxlen
,
5761 mode_t mode
, proc_handler
*proc_handler
)
5763 entry
->procname
= procname
;
5765 entry
->maxlen
= maxlen
;
5767 entry
->proc_handler
= proc_handler
;
5770 static struct ctl_table
*
5771 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
5773 struct ctl_table
*table
= sd_alloc_ctl_entry(13);
5778 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
5779 sizeof(long), 0644, proc_doulongvec_minmax
);
5780 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
5781 sizeof(long), 0644, proc_doulongvec_minmax
);
5782 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
5783 sizeof(int), 0644, proc_dointvec_minmax
);
5784 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
5785 sizeof(int), 0644, proc_dointvec_minmax
);
5786 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
5787 sizeof(int), 0644, proc_dointvec_minmax
);
5788 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
5789 sizeof(int), 0644, proc_dointvec_minmax
);
5790 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
5791 sizeof(int), 0644, proc_dointvec_minmax
);
5792 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
5793 sizeof(int), 0644, proc_dointvec_minmax
);
5794 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
5795 sizeof(int), 0644, proc_dointvec_minmax
);
5796 set_table_entry(&table
[9], "cache_nice_tries",
5797 &sd
->cache_nice_tries
,
5798 sizeof(int), 0644, proc_dointvec_minmax
);
5799 set_table_entry(&table
[10], "flags", &sd
->flags
,
5800 sizeof(int), 0644, proc_dointvec_minmax
);
5801 set_table_entry(&table
[11], "name", sd
->name
,
5802 CORENAME_MAX_SIZE
, 0444, proc_dostring
);
5803 /* &table[12] is terminator */
5808 static ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
5810 struct ctl_table
*entry
, *table
;
5811 struct sched_domain
*sd
;
5812 int domain_num
= 0, i
;
5815 for_each_domain(cpu
, sd
)
5817 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
5822 for_each_domain(cpu
, sd
) {
5823 snprintf(buf
, 32, "domain%d", i
);
5824 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5826 entry
->child
= sd_alloc_ctl_domain_table(sd
);
5833 static struct ctl_table_header
*sd_sysctl_header
;
5834 static void register_sched_domain_sysctl(void)
5836 int i
, cpu_num
= num_possible_cpus();
5837 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
5840 WARN_ON(sd_ctl_dir
[0].child
);
5841 sd_ctl_dir
[0].child
= entry
;
5846 for_each_possible_cpu(i
) {
5847 snprintf(buf
, 32, "cpu%d", i
);
5848 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5850 entry
->child
= sd_alloc_ctl_cpu_table(i
);
5854 WARN_ON(sd_sysctl_header
);
5855 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
5858 /* may be called multiple times per register */
5859 static void unregister_sched_domain_sysctl(void)
5861 if (sd_sysctl_header
)
5862 unregister_sysctl_table(sd_sysctl_header
);
5863 sd_sysctl_header
= NULL
;
5864 if (sd_ctl_dir
[0].child
)
5865 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
5868 static void register_sched_domain_sysctl(void)
5871 static void unregister_sched_domain_sysctl(void)
5876 static void set_rq_online(struct rq
*rq
)
5879 const struct sched_class
*class;
5881 cpumask_set_cpu(rq
->cpu
, rq
->rd
->online
);
5884 for_each_class(class) {
5885 if (class->rq_online
)
5886 class->rq_online(rq
);
5891 static void set_rq_offline(struct rq
*rq
)
5894 const struct sched_class
*class;
5896 for_each_class(class) {
5897 if (class->rq_offline
)
5898 class->rq_offline(rq
);
5901 cpumask_clear_cpu(rq
->cpu
, rq
->rd
->online
);
5907 * migration_call - callback that gets triggered when a CPU is added.
5908 * Here we can start up the necessary migration thread for the new CPU.
5910 static int __cpuinit
5911 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
5913 int cpu
= (long)hcpu
;
5914 unsigned long flags
;
5915 struct rq
*rq
= cpu_rq(cpu
);
5919 case CPU_UP_PREPARE
:
5920 case CPU_UP_PREPARE_FROZEN
:
5921 rq
->calc_load_update
= calc_load_update
;
5925 case CPU_ONLINE_FROZEN
:
5926 /* Update our root-domain */
5927 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5929 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
5933 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5936 #ifdef CONFIG_HOTPLUG_CPU
5938 case CPU_DEAD_FROZEN
:
5939 migrate_live_tasks(cpu
);
5940 /* Idle task back to normal (off runqueue, low prio) */
5941 raw_spin_lock_irq(&rq
->lock
);
5942 deactivate_task(rq
, rq
->idle
, 0);
5943 __setscheduler(rq
, rq
->idle
, SCHED_NORMAL
, 0);
5944 rq
->idle
->sched_class
= &idle_sched_class
;
5945 migrate_dead_tasks(cpu
);
5946 raw_spin_unlock_irq(&rq
->lock
);
5947 migrate_nr_uninterruptible(rq
);
5948 BUG_ON(rq
->nr_running
!= 0);
5949 calc_global_load_remove(rq
);
5953 case CPU_DYING_FROZEN
:
5954 /* Update our root-domain */
5955 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5957 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
5960 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5968 * Register at high priority so that task migration (migrate_all_tasks)
5969 * happens before everything else. This has to be lower priority than
5970 * the notifier in the perf_event subsystem, though.
5972 static struct notifier_block __cpuinitdata migration_notifier
= {
5973 .notifier_call
= migration_call
,
5974 .priority
= CPU_PRI_MIGRATION
,
5977 static int __cpuinit
sched_cpu_active(struct notifier_block
*nfb
,
5978 unsigned long action
, void *hcpu
)
5980 switch (action
& ~CPU_TASKS_FROZEN
) {
5982 case CPU_DOWN_FAILED
:
5983 set_cpu_active((long)hcpu
, true);
5990 static int __cpuinit
sched_cpu_inactive(struct notifier_block
*nfb
,
5991 unsigned long action
, void *hcpu
)
5993 switch (action
& ~CPU_TASKS_FROZEN
) {
5994 case CPU_DOWN_PREPARE
:
5995 set_cpu_active((long)hcpu
, false);
6002 static int __init
migration_init(void)
6004 void *cpu
= (void *)(long)smp_processor_id();
6007 /* Initialize migration for the boot CPU */
6008 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
6009 BUG_ON(err
== NOTIFY_BAD
);
6010 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
6011 register_cpu_notifier(&migration_notifier
);
6013 /* Register cpu active notifiers */
6014 cpu_notifier(sched_cpu_active
, CPU_PRI_SCHED_ACTIVE
);
6015 cpu_notifier(sched_cpu_inactive
, CPU_PRI_SCHED_INACTIVE
);
6019 early_initcall(migration_init
);
6024 #ifdef CONFIG_SCHED_DEBUG
6026 static __read_mostly
int sched_domain_debug_enabled
;
6028 static int __init
sched_domain_debug_setup(char *str
)
6030 sched_domain_debug_enabled
= 1;
6034 early_param("sched_debug", sched_domain_debug_setup
);
6036 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
6037 struct cpumask
*groupmask
)
6039 struct sched_group
*group
= sd
->groups
;
6042 cpulist_scnprintf(str
, sizeof(str
), sched_domain_span(sd
));
6043 cpumask_clear(groupmask
);
6045 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
6047 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
6048 printk("does not load-balance\n");
6050 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
6055 printk(KERN_CONT
"span %s level %s\n", str
, sd
->name
);
6057 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
6058 printk(KERN_ERR
"ERROR: domain->span does not contain "
6061 if (!cpumask_test_cpu(cpu
, sched_group_cpus(group
))) {
6062 printk(KERN_ERR
"ERROR: domain->groups does not contain"
6066 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
6070 printk(KERN_ERR
"ERROR: group is NULL\n");
6074 if (!group
->cpu_power
) {
6075 printk(KERN_CONT
"\n");
6076 printk(KERN_ERR
"ERROR: domain->cpu_power not "
6081 if (!cpumask_weight(sched_group_cpus(group
))) {
6082 printk(KERN_CONT
"\n");
6083 printk(KERN_ERR
"ERROR: empty group\n");
6087 if (cpumask_intersects(groupmask
, sched_group_cpus(group
))) {
6088 printk(KERN_CONT
"\n");
6089 printk(KERN_ERR
"ERROR: repeated CPUs\n");
6093 cpumask_or(groupmask
, groupmask
, sched_group_cpus(group
));
6095 cpulist_scnprintf(str
, sizeof(str
), sched_group_cpus(group
));
6097 printk(KERN_CONT
" %s", str
);
6098 if (group
->cpu_power
!= SCHED_LOAD_SCALE
) {
6099 printk(KERN_CONT
" (cpu_power = %d)",
6103 group
= group
->next
;
6104 } while (group
!= sd
->groups
);
6105 printk(KERN_CONT
"\n");
6107 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
6108 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
6111 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
6112 printk(KERN_ERR
"ERROR: parent span is not a superset "
6113 "of domain->span\n");
6117 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
6119 cpumask_var_t groupmask
;
6122 if (!sched_domain_debug_enabled
)
6126 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
6130 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
6132 if (!alloc_cpumask_var(&groupmask
, GFP_KERNEL
)) {
6133 printk(KERN_DEBUG
"Cannot load-balance (out of memory)\n");
6138 if (sched_domain_debug_one(sd
, cpu
, level
, groupmask
))
6145 free_cpumask_var(groupmask
);
6147 #else /* !CONFIG_SCHED_DEBUG */
6148 # define sched_domain_debug(sd, cpu) do { } while (0)
6149 #endif /* CONFIG_SCHED_DEBUG */
6151 static int sd_degenerate(struct sched_domain
*sd
)
6153 if (cpumask_weight(sched_domain_span(sd
)) == 1)
6156 /* Following flags need at least 2 groups */
6157 if (sd
->flags
& (SD_LOAD_BALANCE
|
6158 SD_BALANCE_NEWIDLE
|
6162 SD_SHARE_PKG_RESOURCES
)) {
6163 if (sd
->groups
!= sd
->groups
->next
)
6167 /* Following flags don't use groups */
6168 if (sd
->flags
& (SD_WAKE_AFFINE
))
6175 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
6177 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
6179 if (sd_degenerate(parent
))
6182 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
6185 /* Flags needing groups don't count if only 1 group in parent */
6186 if (parent
->groups
== parent
->groups
->next
) {
6187 pflags
&= ~(SD_LOAD_BALANCE
|
6188 SD_BALANCE_NEWIDLE
|
6192 SD_SHARE_PKG_RESOURCES
);
6193 if (nr_node_ids
== 1)
6194 pflags
&= ~SD_SERIALIZE
;
6196 if (~cflags
& pflags
)
6202 static void free_rootdomain(struct root_domain
*rd
)
6204 synchronize_sched();
6206 cpupri_cleanup(&rd
->cpupri
);
6208 free_cpumask_var(rd
->rto_mask
);
6209 free_cpumask_var(rd
->online
);
6210 free_cpumask_var(rd
->span
);
6214 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
6216 struct root_domain
*old_rd
= NULL
;
6217 unsigned long flags
;
6219 raw_spin_lock_irqsave(&rq
->lock
, flags
);
6224 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
6227 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
6230 * If we dont want to free the old_rt yet then
6231 * set old_rd to NULL to skip the freeing later
6234 if (!atomic_dec_and_test(&old_rd
->refcount
))
6238 atomic_inc(&rd
->refcount
);
6241 cpumask_set_cpu(rq
->cpu
, rd
->span
);
6242 if (cpumask_test_cpu(rq
->cpu
, cpu_active_mask
))
6245 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
6248 free_rootdomain(old_rd
);
6251 static int init_rootdomain(struct root_domain
*rd
)
6253 memset(rd
, 0, sizeof(*rd
));
6255 if (!alloc_cpumask_var(&rd
->span
, GFP_KERNEL
))
6257 if (!alloc_cpumask_var(&rd
->online
, GFP_KERNEL
))
6259 if (!alloc_cpumask_var(&rd
->rto_mask
, GFP_KERNEL
))
6262 if (cpupri_init(&rd
->cpupri
) != 0)
6267 free_cpumask_var(rd
->rto_mask
);
6269 free_cpumask_var(rd
->online
);
6271 free_cpumask_var(rd
->span
);
6276 static void init_defrootdomain(void)
6278 init_rootdomain(&def_root_domain
);
6280 atomic_set(&def_root_domain
.refcount
, 1);
6283 static struct root_domain
*alloc_rootdomain(void)
6285 struct root_domain
*rd
;
6287 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
6291 if (init_rootdomain(rd
) != 0) {
6300 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
6301 * hold the hotplug lock.
6304 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
6306 struct rq
*rq
= cpu_rq(cpu
);
6307 struct sched_domain
*tmp
;
6309 for (tmp
= sd
; tmp
; tmp
= tmp
->parent
)
6310 tmp
->span_weight
= cpumask_weight(sched_domain_span(tmp
));
6312 /* Remove the sched domains which do not contribute to scheduling. */
6313 for (tmp
= sd
; tmp
; ) {
6314 struct sched_domain
*parent
= tmp
->parent
;
6318 if (sd_parent_degenerate(tmp
, parent
)) {
6319 tmp
->parent
= parent
->parent
;
6321 parent
->parent
->child
= tmp
;
6326 if (sd
&& sd_degenerate(sd
)) {
6332 sched_domain_debug(sd
, cpu
);
6334 rq_attach_root(rq
, rd
);
6335 rcu_assign_pointer(rq
->sd
, sd
);
6338 /* cpus with isolated domains */
6339 static cpumask_var_t cpu_isolated_map
;
6341 /* Setup the mask of cpus configured for isolated domains */
6342 static int __init
isolated_cpu_setup(char *str
)
6344 alloc_bootmem_cpumask_var(&cpu_isolated_map
);
6345 cpulist_parse(str
, cpu_isolated_map
);
6349 __setup("isolcpus=", isolated_cpu_setup
);
6352 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
6353 * to a function which identifies what group(along with sched group) a CPU
6354 * belongs to. The return value of group_fn must be a >= 0 and < nr_cpu_ids
6355 * (due to the fact that we keep track of groups covered with a struct cpumask).
6357 * init_sched_build_groups will build a circular linked list of the groups
6358 * covered by the given span, and will set each group's ->cpumask correctly,
6359 * and ->cpu_power to 0.
6362 init_sched_build_groups(const struct cpumask
*span
,
6363 const struct cpumask
*cpu_map
,
6364 int (*group_fn
)(int cpu
, const struct cpumask
*cpu_map
,
6365 struct sched_group
**sg
,
6366 struct cpumask
*tmpmask
),
6367 struct cpumask
*covered
, struct cpumask
*tmpmask
)
6369 struct sched_group
*first
= NULL
, *last
= NULL
;
6372 cpumask_clear(covered
);
6374 for_each_cpu(i
, span
) {
6375 struct sched_group
*sg
;
6376 int group
= group_fn(i
, cpu_map
, &sg
, tmpmask
);
6379 if (cpumask_test_cpu(i
, covered
))
6382 cpumask_clear(sched_group_cpus(sg
));
6385 for_each_cpu(j
, span
) {
6386 if (group_fn(j
, cpu_map
, NULL
, tmpmask
) != group
)
6389 cpumask_set_cpu(j
, covered
);
6390 cpumask_set_cpu(j
, sched_group_cpus(sg
));
6401 #define SD_NODES_PER_DOMAIN 16
6406 * find_next_best_node - find the next node to include in a sched_domain
6407 * @node: node whose sched_domain we're building
6408 * @used_nodes: nodes already in the sched_domain
6410 * Find the next node to include in a given scheduling domain. Simply
6411 * finds the closest node not already in the @used_nodes map.
6413 * Should use nodemask_t.
6415 static int find_next_best_node(int node
, nodemask_t
*used_nodes
)
6417 int i
, n
, val
, min_val
, best_node
= 0;
6421 for (i
= 0; i
< nr_node_ids
; i
++) {
6422 /* Start at @node */
6423 n
= (node
+ i
) % nr_node_ids
;
6425 if (!nr_cpus_node(n
))
6428 /* Skip already used nodes */
6429 if (node_isset(n
, *used_nodes
))
6432 /* Simple min distance search */
6433 val
= node_distance(node
, n
);
6435 if (val
< min_val
) {
6441 node_set(best_node
, *used_nodes
);
6446 * sched_domain_node_span - get a cpumask for a node's sched_domain
6447 * @node: node whose cpumask we're constructing
6448 * @span: resulting cpumask
6450 * Given a node, construct a good cpumask for its sched_domain to span. It
6451 * should be one that prevents unnecessary balancing, but also spreads tasks
6454 static void sched_domain_node_span(int node
, struct cpumask
*span
)
6456 nodemask_t used_nodes
;
6459 cpumask_clear(span
);
6460 nodes_clear(used_nodes
);
6462 cpumask_or(span
, span
, cpumask_of_node(node
));
6463 node_set(node
, used_nodes
);
6465 for (i
= 1; i
< SD_NODES_PER_DOMAIN
; i
++) {
6466 int next_node
= find_next_best_node(node
, &used_nodes
);
6468 cpumask_or(span
, span
, cpumask_of_node(next_node
));
6471 #endif /* CONFIG_NUMA */
6473 int sched_smt_power_savings
= 0, sched_mc_power_savings
= 0;
6476 * The cpus mask in sched_group and sched_domain hangs off the end.
6478 * ( See the the comments in include/linux/sched.h:struct sched_group
6479 * and struct sched_domain. )
6481 struct static_sched_group
{
6482 struct sched_group sg
;
6483 DECLARE_BITMAP(cpus
, CONFIG_NR_CPUS
);
6486 struct static_sched_domain
{
6487 struct sched_domain sd
;
6488 DECLARE_BITMAP(span
, CONFIG_NR_CPUS
);
6494 cpumask_var_t domainspan
;
6495 cpumask_var_t covered
;
6496 cpumask_var_t notcovered
;
6498 cpumask_var_t nodemask
;
6499 cpumask_var_t this_sibling_map
;
6500 cpumask_var_t this_core_map
;
6501 cpumask_var_t send_covered
;
6502 cpumask_var_t tmpmask
;
6503 struct sched_group
**sched_group_nodes
;
6504 struct root_domain
*rd
;
6508 sa_sched_groups
= 0,
6513 sa_this_sibling_map
,
6515 sa_sched_group_nodes
,
6525 * SMT sched-domains:
6527 #ifdef CONFIG_SCHED_SMT
6528 static DEFINE_PER_CPU(struct static_sched_domain
, cpu_domains
);
6529 static DEFINE_PER_CPU(struct static_sched_group
, sched_groups
);
6532 cpu_to_cpu_group(int cpu
, const struct cpumask
*cpu_map
,
6533 struct sched_group
**sg
, struct cpumask
*unused
)
6536 *sg
= &per_cpu(sched_groups
, cpu
).sg
;
6539 #endif /* CONFIG_SCHED_SMT */
6542 * multi-core sched-domains:
6544 #ifdef CONFIG_SCHED_MC
6545 static DEFINE_PER_CPU(struct static_sched_domain
, core_domains
);
6546 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_core
);
6547 #endif /* CONFIG_SCHED_MC */
6549 #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
6551 cpu_to_core_group(int cpu
, const struct cpumask
*cpu_map
,
6552 struct sched_group
**sg
, struct cpumask
*mask
)
6556 cpumask_and(mask
, topology_thread_cpumask(cpu
), cpu_map
);
6557 group
= cpumask_first(mask
);
6559 *sg
= &per_cpu(sched_group_core
, group
).sg
;
6562 #elif defined(CONFIG_SCHED_MC)
6564 cpu_to_core_group(int cpu
, const struct cpumask
*cpu_map
,
6565 struct sched_group
**sg
, struct cpumask
*unused
)
6568 *sg
= &per_cpu(sched_group_core
, cpu
).sg
;
6573 static DEFINE_PER_CPU(struct static_sched_domain
, phys_domains
);
6574 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_phys
);
6577 cpu_to_phys_group(int cpu
, const struct cpumask
*cpu_map
,
6578 struct sched_group
**sg
, struct cpumask
*mask
)
6581 #ifdef CONFIG_SCHED_MC
6582 cpumask_and(mask
, cpu_coregroup_mask(cpu
), cpu_map
);
6583 group
= cpumask_first(mask
);
6584 #elif defined(CONFIG_SCHED_SMT)
6585 cpumask_and(mask
, topology_thread_cpumask(cpu
), cpu_map
);
6586 group
= cpumask_first(mask
);
6591 *sg
= &per_cpu(sched_group_phys
, group
).sg
;
6597 * The init_sched_build_groups can't handle what we want to do with node
6598 * groups, so roll our own. Now each node has its own list of groups which
6599 * gets dynamically allocated.
6601 static DEFINE_PER_CPU(struct static_sched_domain
, node_domains
);
6602 static struct sched_group
***sched_group_nodes_bycpu
;
6604 static DEFINE_PER_CPU(struct static_sched_domain
, allnodes_domains
);
6605 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_allnodes
);
6607 static int cpu_to_allnodes_group(int cpu
, const struct cpumask
*cpu_map
,
6608 struct sched_group
**sg
,
6609 struct cpumask
*nodemask
)
6613 cpumask_and(nodemask
, cpumask_of_node(cpu_to_node(cpu
)), cpu_map
);
6614 group
= cpumask_first(nodemask
);
6617 *sg
= &per_cpu(sched_group_allnodes
, group
).sg
;
6621 static void init_numa_sched_groups_power(struct sched_group
*group_head
)
6623 struct sched_group
*sg
= group_head
;
6629 for_each_cpu(j
, sched_group_cpus(sg
)) {
6630 struct sched_domain
*sd
;
6632 sd
= &per_cpu(phys_domains
, j
).sd
;
6633 if (j
!= group_first_cpu(sd
->groups
)) {
6635 * Only add "power" once for each
6641 sg
->cpu_power
+= sd
->groups
->cpu_power
;
6644 } while (sg
!= group_head
);
6647 static int build_numa_sched_groups(struct s_data
*d
,
6648 const struct cpumask
*cpu_map
, int num
)
6650 struct sched_domain
*sd
;
6651 struct sched_group
*sg
, *prev
;
6654 cpumask_clear(d
->covered
);
6655 cpumask_and(d
->nodemask
, cpumask_of_node(num
), cpu_map
);
6656 if (cpumask_empty(d
->nodemask
)) {
6657 d
->sched_group_nodes
[num
] = NULL
;
6661 sched_domain_node_span(num
, d
->domainspan
);
6662 cpumask_and(d
->domainspan
, d
->domainspan
, cpu_map
);
6664 sg
= kmalloc_node(sizeof(struct sched_group
) + cpumask_size(),
6667 printk(KERN_WARNING
"Can not alloc domain group for node %d\n",
6671 d
->sched_group_nodes
[num
] = sg
;
6673 for_each_cpu(j
, d
->nodemask
) {
6674 sd
= &per_cpu(node_domains
, j
).sd
;
6679 cpumask_copy(sched_group_cpus(sg
), d
->nodemask
);
6681 cpumask_or(d
->covered
, d
->covered
, d
->nodemask
);
6684 for (j
= 0; j
< nr_node_ids
; j
++) {
6685 n
= (num
+ j
) % nr_node_ids
;
6686 cpumask_complement(d
->notcovered
, d
->covered
);
6687 cpumask_and(d
->tmpmask
, d
->notcovered
, cpu_map
);
6688 cpumask_and(d
->tmpmask
, d
->tmpmask
, d
->domainspan
);
6689 if (cpumask_empty(d
->tmpmask
))
6691 cpumask_and(d
->tmpmask
, d
->tmpmask
, cpumask_of_node(n
));
6692 if (cpumask_empty(d
->tmpmask
))
6694 sg
= kmalloc_node(sizeof(struct sched_group
) + cpumask_size(),
6698 "Can not alloc domain group for node %d\n", j
);
6702 cpumask_copy(sched_group_cpus(sg
), d
->tmpmask
);
6703 sg
->next
= prev
->next
;
6704 cpumask_or(d
->covered
, d
->covered
, d
->tmpmask
);
6711 #endif /* CONFIG_NUMA */
6714 /* Free memory allocated for various sched_group structures */
6715 static void free_sched_groups(const struct cpumask
*cpu_map
,
6716 struct cpumask
*nodemask
)
6720 for_each_cpu(cpu
, cpu_map
) {
6721 struct sched_group
**sched_group_nodes
6722 = sched_group_nodes_bycpu
[cpu
];
6724 if (!sched_group_nodes
)
6727 for (i
= 0; i
< nr_node_ids
; i
++) {
6728 struct sched_group
*oldsg
, *sg
= sched_group_nodes
[i
];
6730 cpumask_and(nodemask
, cpumask_of_node(i
), cpu_map
);
6731 if (cpumask_empty(nodemask
))
6741 if (oldsg
!= sched_group_nodes
[i
])
6744 kfree(sched_group_nodes
);
6745 sched_group_nodes_bycpu
[cpu
] = NULL
;
6748 #else /* !CONFIG_NUMA */
6749 static void free_sched_groups(const struct cpumask
*cpu_map
,
6750 struct cpumask
*nodemask
)
6753 #endif /* CONFIG_NUMA */
6756 * Initialize sched groups cpu_power.
6758 * cpu_power indicates the capacity of sched group, which is used while
6759 * distributing the load between different sched groups in a sched domain.
6760 * Typically cpu_power for all the groups in a sched domain will be same unless
6761 * there are asymmetries in the topology. If there are asymmetries, group
6762 * having more cpu_power will pickup more load compared to the group having
6765 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
6767 struct sched_domain
*child
;
6768 struct sched_group
*group
;
6772 WARN_ON(!sd
|| !sd
->groups
);
6774 if (cpu
!= group_first_cpu(sd
->groups
))
6779 sd
->groups
->cpu_power
= 0;
6782 power
= SCHED_LOAD_SCALE
;
6783 weight
= cpumask_weight(sched_domain_span(sd
));
6785 * SMT siblings share the power of a single core.
6786 * Usually multiple threads get a better yield out of
6787 * that one core than a single thread would have,
6788 * reflect that in sd->smt_gain.
6790 if ((sd
->flags
& SD_SHARE_CPUPOWER
) && weight
> 1) {
6791 power
*= sd
->smt_gain
;
6793 power
>>= SCHED_LOAD_SHIFT
;
6795 sd
->groups
->cpu_power
+= power
;
6800 * Add cpu_power of each child group to this groups cpu_power.
6802 group
= child
->groups
;
6804 sd
->groups
->cpu_power
+= group
->cpu_power
;
6805 group
= group
->next
;
6806 } while (group
!= child
->groups
);
6810 * Initializers for schedule domains
6811 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
6814 #ifdef CONFIG_SCHED_DEBUG
6815 # define SD_INIT_NAME(sd, type) sd->name = #type
6817 # define SD_INIT_NAME(sd, type) do { } while (0)
6820 #define SD_INIT(sd, type) sd_init_##type(sd)
6822 #define SD_INIT_FUNC(type) \
6823 static noinline void sd_init_##type(struct sched_domain *sd) \
6825 memset(sd, 0, sizeof(*sd)); \
6826 *sd = SD_##type##_INIT; \
6827 sd->level = SD_LV_##type; \
6828 SD_INIT_NAME(sd, type); \
6833 SD_INIT_FUNC(ALLNODES
)
6836 #ifdef CONFIG_SCHED_SMT
6837 SD_INIT_FUNC(SIBLING
)
6839 #ifdef CONFIG_SCHED_MC
6843 static int default_relax_domain_level
= -1;
6845 static int __init
setup_relax_domain_level(char *str
)
6849 val
= simple_strtoul(str
, NULL
, 0);
6850 if (val
< SD_LV_MAX
)
6851 default_relax_domain_level
= val
;
6855 __setup("relax_domain_level=", setup_relax_domain_level
);
6857 static void set_domain_attribute(struct sched_domain
*sd
,
6858 struct sched_domain_attr
*attr
)
6862 if (!attr
|| attr
->relax_domain_level
< 0) {
6863 if (default_relax_domain_level
< 0)
6866 request
= default_relax_domain_level
;
6868 request
= attr
->relax_domain_level
;
6869 if (request
< sd
->level
) {
6870 /* turn off idle balance on this domain */
6871 sd
->flags
&= ~(SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
6873 /* turn on idle balance on this domain */
6874 sd
->flags
|= (SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
6878 static void __free_domain_allocs(struct s_data
*d
, enum s_alloc what
,
6879 const struct cpumask
*cpu_map
)
6882 case sa_sched_groups
:
6883 free_sched_groups(cpu_map
, d
->tmpmask
); /* fall through */
6884 d
->sched_group_nodes
= NULL
;
6886 free_rootdomain(d
->rd
); /* fall through */
6888 free_cpumask_var(d
->tmpmask
); /* fall through */
6889 case sa_send_covered
:
6890 free_cpumask_var(d
->send_covered
); /* fall through */
6891 case sa_this_core_map
:
6892 free_cpumask_var(d
->this_core_map
); /* fall through */
6893 case sa_this_sibling_map
:
6894 free_cpumask_var(d
->this_sibling_map
); /* fall through */
6896 free_cpumask_var(d
->nodemask
); /* fall through */
6897 case sa_sched_group_nodes
:
6899 kfree(d
->sched_group_nodes
); /* fall through */
6901 free_cpumask_var(d
->notcovered
); /* fall through */
6903 free_cpumask_var(d
->covered
); /* fall through */
6905 free_cpumask_var(d
->domainspan
); /* fall through */
6912 static enum s_alloc
__visit_domain_allocation_hell(struct s_data
*d
,
6913 const struct cpumask
*cpu_map
)
6916 if (!alloc_cpumask_var(&d
->domainspan
, GFP_KERNEL
))
6918 if (!alloc_cpumask_var(&d
->covered
, GFP_KERNEL
))
6919 return sa_domainspan
;
6920 if (!alloc_cpumask_var(&d
->notcovered
, GFP_KERNEL
))
6922 /* Allocate the per-node list of sched groups */
6923 d
->sched_group_nodes
= kcalloc(nr_node_ids
,
6924 sizeof(struct sched_group
*), GFP_KERNEL
);
6925 if (!d
->sched_group_nodes
) {
6926 printk(KERN_WARNING
"Can not alloc sched group node list\n");
6927 return sa_notcovered
;
6929 sched_group_nodes_bycpu
[cpumask_first(cpu_map
)] = d
->sched_group_nodes
;
6931 if (!alloc_cpumask_var(&d
->nodemask
, GFP_KERNEL
))
6932 return sa_sched_group_nodes
;
6933 if (!alloc_cpumask_var(&d
->this_sibling_map
, GFP_KERNEL
))
6935 if (!alloc_cpumask_var(&d
->this_core_map
, GFP_KERNEL
))
6936 return sa_this_sibling_map
;
6937 if (!alloc_cpumask_var(&d
->send_covered
, GFP_KERNEL
))
6938 return sa_this_core_map
;
6939 if (!alloc_cpumask_var(&d
->tmpmask
, GFP_KERNEL
))
6940 return sa_send_covered
;
6941 d
->rd
= alloc_rootdomain();
6943 printk(KERN_WARNING
"Cannot alloc root domain\n");
6946 return sa_rootdomain
;
6949 static struct sched_domain
*__build_numa_sched_domains(struct s_data
*d
,
6950 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
, int i
)
6952 struct sched_domain
*sd
= NULL
;
6954 struct sched_domain
*parent
;
6957 if (cpumask_weight(cpu_map
) >
6958 SD_NODES_PER_DOMAIN
* cpumask_weight(d
->nodemask
)) {
6959 sd
= &per_cpu(allnodes_domains
, i
).sd
;
6960 SD_INIT(sd
, ALLNODES
);
6961 set_domain_attribute(sd
, attr
);
6962 cpumask_copy(sched_domain_span(sd
), cpu_map
);
6963 cpu_to_allnodes_group(i
, cpu_map
, &sd
->groups
, d
->tmpmask
);
6968 sd
= &per_cpu(node_domains
, i
).sd
;
6970 set_domain_attribute(sd
, attr
);
6971 sched_domain_node_span(cpu_to_node(i
), sched_domain_span(sd
));
6972 sd
->parent
= parent
;
6975 cpumask_and(sched_domain_span(sd
), sched_domain_span(sd
), cpu_map
);
6980 static struct sched_domain
*__build_cpu_sched_domain(struct s_data
*d
,
6981 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
6982 struct sched_domain
*parent
, int i
)
6984 struct sched_domain
*sd
;
6985 sd
= &per_cpu(phys_domains
, i
).sd
;
6987 set_domain_attribute(sd
, attr
);
6988 cpumask_copy(sched_domain_span(sd
), d
->nodemask
);
6989 sd
->parent
= parent
;
6992 cpu_to_phys_group(i
, cpu_map
, &sd
->groups
, d
->tmpmask
);
6996 static struct sched_domain
*__build_mc_sched_domain(struct s_data
*d
,
6997 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
6998 struct sched_domain
*parent
, int i
)
7000 struct sched_domain
*sd
= parent
;
7001 #ifdef CONFIG_SCHED_MC
7002 sd
= &per_cpu(core_domains
, i
).sd
;
7004 set_domain_attribute(sd
, attr
);
7005 cpumask_and(sched_domain_span(sd
), cpu_map
, cpu_coregroup_mask(i
));
7006 sd
->parent
= parent
;
7008 cpu_to_core_group(i
, cpu_map
, &sd
->groups
, d
->tmpmask
);
7013 static struct sched_domain
*__build_smt_sched_domain(struct s_data
*d
,
7014 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
7015 struct sched_domain
*parent
, int i
)
7017 struct sched_domain
*sd
= parent
;
7018 #ifdef CONFIG_SCHED_SMT
7019 sd
= &per_cpu(cpu_domains
, i
).sd
;
7020 SD_INIT(sd
, SIBLING
);
7021 set_domain_attribute(sd
, attr
);
7022 cpumask_and(sched_domain_span(sd
), cpu_map
, topology_thread_cpumask(i
));
7023 sd
->parent
= parent
;
7025 cpu_to_cpu_group(i
, cpu_map
, &sd
->groups
, d
->tmpmask
);
7030 static void build_sched_groups(struct s_data
*d
, enum sched_domain_level l
,
7031 const struct cpumask
*cpu_map
, int cpu
)
7034 #ifdef CONFIG_SCHED_SMT
7035 case SD_LV_SIBLING
: /* set up CPU (sibling) groups */
7036 cpumask_and(d
->this_sibling_map
, cpu_map
,
7037 topology_thread_cpumask(cpu
));
7038 if (cpu
== cpumask_first(d
->this_sibling_map
))
7039 init_sched_build_groups(d
->this_sibling_map
, cpu_map
,
7041 d
->send_covered
, d
->tmpmask
);
7044 #ifdef CONFIG_SCHED_MC
7045 case SD_LV_MC
: /* set up multi-core groups */
7046 cpumask_and(d
->this_core_map
, cpu_map
, cpu_coregroup_mask(cpu
));
7047 if (cpu
== cpumask_first(d
->this_core_map
))
7048 init_sched_build_groups(d
->this_core_map
, cpu_map
,
7050 d
->send_covered
, d
->tmpmask
);
7053 case SD_LV_CPU
: /* set up physical groups */
7054 cpumask_and(d
->nodemask
, cpumask_of_node(cpu
), cpu_map
);
7055 if (!cpumask_empty(d
->nodemask
))
7056 init_sched_build_groups(d
->nodemask
, cpu_map
,
7058 d
->send_covered
, d
->tmpmask
);
7061 case SD_LV_ALLNODES
:
7062 init_sched_build_groups(cpu_map
, cpu_map
, &cpu_to_allnodes_group
,
7063 d
->send_covered
, d
->tmpmask
);
7072 * Build sched domains for a given set of cpus and attach the sched domains
7073 * to the individual cpus
7075 static int __build_sched_domains(const struct cpumask
*cpu_map
,
7076 struct sched_domain_attr
*attr
)
7078 enum s_alloc alloc_state
= sa_none
;
7080 struct sched_domain
*sd
;
7086 alloc_state
= __visit_domain_allocation_hell(&d
, cpu_map
);
7087 if (alloc_state
!= sa_rootdomain
)
7089 alloc_state
= sa_sched_groups
;
7092 * Set up domains for cpus specified by the cpu_map.
7094 for_each_cpu(i
, cpu_map
) {
7095 cpumask_and(d
.nodemask
, cpumask_of_node(cpu_to_node(i
)),
7098 sd
= __build_numa_sched_domains(&d
, cpu_map
, attr
, i
);
7099 sd
= __build_cpu_sched_domain(&d
, cpu_map
, attr
, sd
, i
);
7100 sd
= __build_mc_sched_domain(&d
, cpu_map
, attr
, sd
, i
);
7101 sd
= __build_smt_sched_domain(&d
, cpu_map
, attr
, sd
, i
);
7104 for_each_cpu(i
, cpu_map
) {
7105 build_sched_groups(&d
, SD_LV_SIBLING
, cpu_map
, i
);
7106 build_sched_groups(&d
, SD_LV_MC
, cpu_map
, i
);
7109 /* Set up physical groups */
7110 for (i
= 0; i
< nr_node_ids
; i
++)
7111 build_sched_groups(&d
, SD_LV_CPU
, cpu_map
, i
);
7114 /* Set up node groups */
7116 build_sched_groups(&d
, SD_LV_ALLNODES
, cpu_map
, 0);
7118 for (i
= 0; i
< nr_node_ids
; i
++)
7119 if (build_numa_sched_groups(&d
, cpu_map
, i
))
7123 /* Calculate CPU power for physical packages and nodes */
7124 #ifdef CONFIG_SCHED_SMT
7125 for_each_cpu(i
, cpu_map
) {
7126 sd
= &per_cpu(cpu_domains
, i
).sd
;
7127 init_sched_groups_power(i
, sd
);
7130 #ifdef CONFIG_SCHED_MC
7131 for_each_cpu(i
, cpu_map
) {
7132 sd
= &per_cpu(core_domains
, i
).sd
;
7133 init_sched_groups_power(i
, sd
);
7137 for_each_cpu(i
, cpu_map
) {
7138 sd
= &per_cpu(phys_domains
, i
).sd
;
7139 init_sched_groups_power(i
, sd
);
7143 for (i
= 0; i
< nr_node_ids
; i
++)
7144 init_numa_sched_groups_power(d
.sched_group_nodes
[i
]);
7146 if (d
.sd_allnodes
) {
7147 struct sched_group
*sg
;
7149 cpu_to_allnodes_group(cpumask_first(cpu_map
), cpu_map
, &sg
,
7151 init_numa_sched_groups_power(sg
);
7155 /* Attach the domains */
7156 for_each_cpu(i
, cpu_map
) {
7157 #ifdef CONFIG_SCHED_SMT
7158 sd
= &per_cpu(cpu_domains
, i
).sd
;
7159 #elif defined(CONFIG_SCHED_MC)
7160 sd
= &per_cpu(core_domains
, i
).sd
;
7162 sd
= &per_cpu(phys_domains
, i
).sd
;
7164 cpu_attach_domain(sd
, d
.rd
, i
);
7167 d
.sched_group_nodes
= NULL
; /* don't free this we still need it */
7168 __free_domain_allocs(&d
, sa_tmpmask
, cpu_map
);
7172 __free_domain_allocs(&d
, alloc_state
, cpu_map
);
7176 static int build_sched_domains(const struct cpumask
*cpu_map
)
7178 return __build_sched_domains(cpu_map
, NULL
);
7181 static cpumask_var_t
*doms_cur
; /* current sched domains */
7182 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
7183 static struct sched_domain_attr
*dattr_cur
;
7184 /* attribues of custom domains in 'doms_cur' */
7187 * Special case: If a kmalloc of a doms_cur partition (array of
7188 * cpumask) fails, then fallback to a single sched domain,
7189 * as determined by the single cpumask fallback_doms.
7191 static cpumask_var_t fallback_doms
;
7194 * arch_update_cpu_topology lets virtualized architectures update the
7195 * cpu core maps. It is supposed to return 1 if the topology changed
7196 * or 0 if it stayed the same.
7198 int __attribute__((weak
)) arch_update_cpu_topology(void)
7203 cpumask_var_t
*alloc_sched_domains(unsigned int ndoms
)
7206 cpumask_var_t
*doms
;
7208 doms
= kmalloc(sizeof(*doms
) * ndoms
, GFP_KERNEL
);
7211 for (i
= 0; i
< ndoms
; i
++) {
7212 if (!alloc_cpumask_var(&doms
[i
], GFP_KERNEL
)) {
7213 free_sched_domains(doms
, i
);
7220 void free_sched_domains(cpumask_var_t doms
[], unsigned int ndoms
)
7223 for (i
= 0; i
< ndoms
; i
++)
7224 free_cpumask_var(doms
[i
]);
7229 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
7230 * For now this just excludes isolated cpus, but could be used to
7231 * exclude other special cases in the future.
7233 static int arch_init_sched_domains(const struct cpumask
*cpu_map
)
7237 arch_update_cpu_topology();
7239 doms_cur
= alloc_sched_domains(ndoms_cur
);
7241 doms_cur
= &fallback_doms
;
7242 cpumask_andnot(doms_cur
[0], cpu_map
, cpu_isolated_map
);
7244 err
= build_sched_domains(doms_cur
[0]);
7245 register_sched_domain_sysctl();
7250 static void arch_destroy_sched_domains(const struct cpumask
*cpu_map
,
7251 struct cpumask
*tmpmask
)
7253 free_sched_groups(cpu_map
, tmpmask
);
7257 * Detach sched domains from a group of cpus specified in cpu_map
7258 * These cpus will now be attached to the NULL domain
7260 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
7262 /* Save because hotplug lock held. */
7263 static DECLARE_BITMAP(tmpmask
, CONFIG_NR_CPUS
);
7266 for_each_cpu(i
, cpu_map
)
7267 cpu_attach_domain(NULL
, &def_root_domain
, i
);
7268 synchronize_sched();
7269 arch_destroy_sched_domains(cpu_map
, to_cpumask(tmpmask
));
7272 /* handle null as "default" */
7273 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
7274 struct sched_domain_attr
*new, int idx_new
)
7276 struct sched_domain_attr tmp
;
7283 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
7284 new ? (new + idx_new
) : &tmp
,
7285 sizeof(struct sched_domain_attr
));
7289 * Partition sched domains as specified by the 'ndoms_new'
7290 * cpumasks in the array doms_new[] of cpumasks. This compares
7291 * doms_new[] to the current sched domain partitioning, doms_cur[].
7292 * It destroys each deleted domain and builds each new domain.
7294 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
7295 * The masks don't intersect (don't overlap.) We should setup one
7296 * sched domain for each mask. CPUs not in any of the cpumasks will
7297 * not be load balanced. If the same cpumask appears both in the
7298 * current 'doms_cur' domains and in the new 'doms_new', we can leave
7301 * The passed in 'doms_new' should be allocated using
7302 * alloc_sched_domains. This routine takes ownership of it and will
7303 * free_sched_domains it when done with it. If the caller failed the
7304 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
7305 * and partition_sched_domains() will fallback to the single partition
7306 * 'fallback_doms', it also forces the domains to be rebuilt.
7308 * If doms_new == NULL it will be replaced with cpu_online_mask.
7309 * ndoms_new == 0 is a special case for destroying existing domains,
7310 * and it will not create the default domain.
7312 * Call with hotplug lock held
7314 void partition_sched_domains(int ndoms_new
, cpumask_var_t doms_new
[],
7315 struct sched_domain_attr
*dattr_new
)
7320 mutex_lock(&sched_domains_mutex
);
7322 /* always unregister in case we don't destroy any domains */
7323 unregister_sched_domain_sysctl();
7325 /* Let architecture update cpu core mappings. */
7326 new_topology
= arch_update_cpu_topology();
7328 n
= doms_new
? ndoms_new
: 0;
7330 /* Destroy deleted domains */
7331 for (i
= 0; i
< ndoms_cur
; i
++) {
7332 for (j
= 0; j
< n
&& !new_topology
; j
++) {
7333 if (cpumask_equal(doms_cur
[i
], doms_new
[j
])
7334 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
7337 /* no match - a current sched domain not in new doms_new[] */
7338 detach_destroy_domains(doms_cur
[i
]);
7343 if (doms_new
== NULL
) {
7345 doms_new
= &fallback_doms
;
7346 cpumask_andnot(doms_new
[0], cpu_active_mask
, cpu_isolated_map
);
7347 WARN_ON_ONCE(dattr_new
);
7350 /* Build new domains */
7351 for (i
= 0; i
< ndoms_new
; i
++) {
7352 for (j
= 0; j
< ndoms_cur
&& !new_topology
; j
++) {
7353 if (cpumask_equal(doms_new
[i
], doms_cur
[j
])
7354 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
7357 /* no match - add a new doms_new */
7358 __build_sched_domains(doms_new
[i
],
7359 dattr_new
? dattr_new
+ i
: NULL
);
7364 /* Remember the new sched domains */
7365 if (doms_cur
!= &fallback_doms
)
7366 free_sched_domains(doms_cur
, ndoms_cur
);
7367 kfree(dattr_cur
); /* kfree(NULL) is safe */
7368 doms_cur
= doms_new
;
7369 dattr_cur
= dattr_new
;
7370 ndoms_cur
= ndoms_new
;
7372 register_sched_domain_sysctl();
7374 mutex_unlock(&sched_domains_mutex
);
7377 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
7378 static void arch_reinit_sched_domains(void)
7382 /* Destroy domains first to force the rebuild */
7383 partition_sched_domains(0, NULL
, NULL
);
7385 rebuild_sched_domains();
7389 static ssize_t
sched_power_savings_store(const char *buf
, size_t count
, int smt
)
7391 unsigned int level
= 0;
7393 if (sscanf(buf
, "%u", &level
) != 1)
7397 * level is always be positive so don't check for
7398 * level < POWERSAVINGS_BALANCE_NONE which is 0
7399 * What happens on 0 or 1 byte write,
7400 * need to check for count as well?
7403 if (level
>= MAX_POWERSAVINGS_BALANCE_LEVELS
)
7407 sched_smt_power_savings
= level
;
7409 sched_mc_power_savings
= level
;
7411 arch_reinit_sched_domains();
7416 #ifdef CONFIG_SCHED_MC
7417 static ssize_t
sched_mc_power_savings_show(struct sysdev_class
*class,
7418 struct sysdev_class_attribute
*attr
,
7421 return sprintf(page
, "%u\n", sched_mc_power_savings
);
7423 static ssize_t
sched_mc_power_savings_store(struct sysdev_class
*class,
7424 struct sysdev_class_attribute
*attr
,
7425 const char *buf
, size_t count
)
7427 return sched_power_savings_store(buf
, count
, 0);
7429 static SYSDEV_CLASS_ATTR(sched_mc_power_savings
, 0644,
7430 sched_mc_power_savings_show
,
7431 sched_mc_power_savings_store
);
7434 #ifdef CONFIG_SCHED_SMT
7435 static ssize_t
sched_smt_power_savings_show(struct sysdev_class
*dev
,
7436 struct sysdev_class_attribute
*attr
,
7439 return sprintf(page
, "%u\n", sched_smt_power_savings
);
7441 static ssize_t
sched_smt_power_savings_store(struct sysdev_class
*dev
,
7442 struct sysdev_class_attribute
*attr
,
7443 const char *buf
, size_t count
)
7445 return sched_power_savings_store(buf
, count
, 1);
7447 static SYSDEV_CLASS_ATTR(sched_smt_power_savings
, 0644,
7448 sched_smt_power_savings_show
,
7449 sched_smt_power_savings_store
);
7452 int __init
sched_create_sysfs_power_savings_entries(struct sysdev_class
*cls
)
7456 #ifdef CONFIG_SCHED_SMT
7458 err
= sysfs_create_file(&cls
->kset
.kobj
,
7459 &attr_sched_smt_power_savings
.attr
);
7461 #ifdef CONFIG_SCHED_MC
7462 if (!err
&& mc_capable())
7463 err
= sysfs_create_file(&cls
->kset
.kobj
,
7464 &attr_sched_mc_power_savings
.attr
);
7468 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
7471 * Update cpusets according to cpu_active mask. If cpusets are
7472 * disabled, cpuset_update_active_cpus() becomes a simple wrapper
7473 * around partition_sched_domains().
7475 static int cpuset_cpu_active(struct notifier_block
*nfb
, unsigned long action
,
7478 switch (action
& ~CPU_TASKS_FROZEN
) {
7480 case CPU_DOWN_FAILED
:
7481 cpuset_update_active_cpus();
7488 static int cpuset_cpu_inactive(struct notifier_block
*nfb
, unsigned long action
,
7491 switch (action
& ~CPU_TASKS_FROZEN
) {
7492 case CPU_DOWN_PREPARE
:
7493 cpuset_update_active_cpus();
7500 static int update_runtime(struct notifier_block
*nfb
,
7501 unsigned long action
, void *hcpu
)
7503 int cpu
= (int)(long)hcpu
;
7506 case CPU_DOWN_PREPARE
:
7507 case CPU_DOWN_PREPARE_FROZEN
:
7508 disable_runtime(cpu_rq(cpu
));
7511 case CPU_DOWN_FAILED
:
7512 case CPU_DOWN_FAILED_FROZEN
:
7514 case CPU_ONLINE_FROZEN
:
7515 enable_runtime(cpu_rq(cpu
));
7523 void __init
sched_init_smp(void)
7525 cpumask_var_t non_isolated_cpus
;
7527 alloc_cpumask_var(&non_isolated_cpus
, GFP_KERNEL
);
7528 alloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
7530 #if defined(CONFIG_NUMA)
7531 sched_group_nodes_bycpu
= kzalloc(nr_cpu_ids
* sizeof(void **),
7533 BUG_ON(sched_group_nodes_bycpu
== NULL
);
7536 mutex_lock(&sched_domains_mutex
);
7537 arch_init_sched_domains(cpu_active_mask
);
7538 cpumask_andnot(non_isolated_cpus
, cpu_possible_mask
, cpu_isolated_map
);
7539 if (cpumask_empty(non_isolated_cpus
))
7540 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus
);
7541 mutex_unlock(&sched_domains_mutex
);
7544 hotcpu_notifier(cpuset_cpu_active
, CPU_PRI_CPUSET_ACTIVE
);
7545 hotcpu_notifier(cpuset_cpu_inactive
, CPU_PRI_CPUSET_INACTIVE
);
7547 /* RT runtime code needs to handle some hotplug events */
7548 hotcpu_notifier(update_runtime
, 0);
7552 /* Move init over to a non-isolated CPU */
7553 if (set_cpus_allowed_ptr(current
, non_isolated_cpus
) < 0)
7555 sched_init_granularity();
7556 free_cpumask_var(non_isolated_cpus
);
7558 init_sched_rt_class();
7561 void __init
sched_init_smp(void)
7563 sched_init_granularity();
7565 #endif /* CONFIG_SMP */
7567 const_debug
unsigned int sysctl_timer_migration
= 1;
7569 int in_sched_functions(unsigned long addr
)
7571 return in_lock_functions(addr
) ||
7572 (addr
>= (unsigned long)__sched_text_start
7573 && addr
< (unsigned long)__sched_text_end
);
7576 static void init_cfs_rq(struct cfs_rq
*cfs_rq
, struct rq
*rq
)
7578 cfs_rq
->tasks_timeline
= RB_ROOT
;
7579 INIT_LIST_HEAD(&cfs_rq
->tasks
);
7580 #ifdef CONFIG_FAIR_GROUP_SCHED
7583 cfs_rq
->min_vruntime
= (u64
)(-(1LL << 20));
7586 static void init_rt_rq(struct rt_rq
*rt_rq
, struct rq
*rq
)
7588 struct rt_prio_array
*array
;
7591 array
= &rt_rq
->active
;
7592 for (i
= 0; i
< MAX_RT_PRIO
; i
++) {
7593 INIT_LIST_HEAD(array
->queue
+ i
);
7594 __clear_bit(i
, array
->bitmap
);
7596 /* delimiter for bitsearch: */
7597 __set_bit(MAX_RT_PRIO
, array
->bitmap
);
7599 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
7600 rt_rq
->highest_prio
.curr
= MAX_RT_PRIO
;
7602 rt_rq
->highest_prio
.next
= MAX_RT_PRIO
;
7606 rt_rq
->rt_nr_migratory
= 0;
7607 rt_rq
->overloaded
= 0;
7608 plist_head_init_raw(&rt_rq
->pushable_tasks
, &rq
->lock
);
7612 rt_rq
->rt_throttled
= 0;
7613 rt_rq
->rt_runtime
= 0;
7614 raw_spin_lock_init(&rt_rq
->rt_runtime_lock
);
7616 #ifdef CONFIG_RT_GROUP_SCHED
7617 rt_rq
->rt_nr_boosted
= 0;
7622 #ifdef CONFIG_FAIR_GROUP_SCHED
7623 static void init_tg_cfs_entry(struct task_group
*tg
, struct cfs_rq
*cfs_rq
,
7624 struct sched_entity
*se
, int cpu
, int add
,
7625 struct sched_entity
*parent
)
7627 struct rq
*rq
= cpu_rq(cpu
);
7628 tg
->cfs_rq
[cpu
] = cfs_rq
;
7629 init_cfs_rq(cfs_rq
, rq
);
7632 list_add(&cfs_rq
->leaf_cfs_rq_list
, &rq
->leaf_cfs_rq_list
);
7635 /* se could be NULL for init_task_group */
7640 se
->cfs_rq
= &rq
->cfs
;
7642 se
->cfs_rq
= parent
->my_q
;
7645 se
->load
.weight
= tg
->shares
;
7646 se
->load
.inv_weight
= 0;
7647 se
->parent
= parent
;
7651 #ifdef CONFIG_RT_GROUP_SCHED
7652 static void init_tg_rt_entry(struct task_group
*tg
, struct rt_rq
*rt_rq
,
7653 struct sched_rt_entity
*rt_se
, int cpu
, int add
,
7654 struct sched_rt_entity
*parent
)
7656 struct rq
*rq
= cpu_rq(cpu
);
7658 tg
->rt_rq
[cpu
] = rt_rq
;
7659 init_rt_rq(rt_rq
, rq
);
7661 rt_rq
->rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
7663 list_add(&rt_rq
->leaf_rt_rq_list
, &rq
->leaf_rt_rq_list
);
7665 tg
->rt_se
[cpu
] = rt_se
;
7670 rt_se
->rt_rq
= &rq
->rt
;
7672 rt_se
->rt_rq
= parent
->my_q
;
7674 rt_se
->my_q
= rt_rq
;
7675 rt_se
->parent
= parent
;
7676 INIT_LIST_HEAD(&rt_se
->run_list
);
7680 void __init
sched_init(void)
7683 unsigned long alloc_size
= 0, ptr
;
7685 #ifdef CONFIG_FAIR_GROUP_SCHED
7686 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
7688 #ifdef CONFIG_RT_GROUP_SCHED
7689 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
7691 #ifdef CONFIG_CPUMASK_OFFSTACK
7692 alloc_size
+= num_possible_cpus() * cpumask_size();
7695 ptr
= (unsigned long)kzalloc(alloc_size
, GFP_NOWAIT
);
7697 #ifdef CONFIG_FAIR_GROUP_SCHED
7698 init_task_group
.se
= (struct sched_entity
**)ptr
;
7699 ptr
+= nr_cpu_ids
* sizeof(void **);
7701 init_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
7702 ptr
+= nr_cpu_ids
* sizeof(void **);
7704 #endif /* CONFIG_FAIR_GROUP_SCHED */
7705 #ifdef CONFIG_RT_GROUP_SCHED
7706 init_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
7707 ptr
+= nr_cpu_ids
* sizeof(void **);
7709 init_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
7710 ptr
+= nr_cpu_ids
* sizeof(void **);
7712 #endif /* CONFIG_RT_GROUP_SCHED */
7713 #ifdef CONFIG_CPUMASK_OFFSTACK
7714 for_each_possible_cpu(i
) {
7715 per_cpu(load_balance_tmpmask
, i
) = (void *)ptr
;
7716 ptr
+= cpumask_size();
7718 #endif /* CONFIG_CPUMASK_OFFSTACK */
7722 init_defrootdomain();
7725 init_rt_bandwidth(&def_rt_bandwidth
,
7726 global_rt_period(), global_rt_runtime());
7728 #ifdef CONFIG_RT_GROUP_SCHED
7729 init_rt_bandwidth(&init_task_group
.rt_bandwidth
,
7730 global_rt_period(), global_rt_runtime());
7731 #endif /* CONFIG_RT_GROUP_SCHED */
7733 #ifdef CONFIG_CGROUP_SCHED
7734 list_add(&init_task_group
.list
, &task_groups
);
7735 INIT_LIST_HEAD(&init_task_group
.children
);
7737 #endif /* CONFIG_CGROUP_SCHED */
7739 #if defined CONFIG_FAIR_GROUP_SCHED && defined CONFIG_SMP
7740 update_shares_data
= __alloc_percpu(nr_cpu_ids
* sizeof(unsigned long),
7741 __alignof__(unsigned long));
7743 for_each_possible_cpu(i
) {
7747 raw_spin_lock_init(&rq
->lock
);
7749 rq
->calc_load_active
= 0;
7750 rq
->calc_load_update
= jiffies
+ LOAD_FREQ
;
7751 init_cfs_rq(&rq
->cfs
, rq
);
7752 init_rt_rq(&rq
->rt
, rq
);
7753 #ifdef CONFIG_FAIR_GROUP_SCHED
7754 init_task_group
.shares
= init_task_group_load
;
7755 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
7756 #ifdef CONFIG_CGROUP_SCHED
7758 * How much cpu bandwidth does init_task_group get?
7760 * In case of task-groups formed thr' the cgroup filesystem, it
7761 * gets 100% of the cpu resources in the system. This overall
7762 * system cpu resource is divided among the tasks of
7763 * init_task_group and its child task-groups in a fair manner,
7764 * based on each entity's (task or task-group's) weight
7765 * (se->load.weight).
7767 * In other words, if init_task_group has 10 tasks of weight
7768 * 1024) and two child groups A0 and A1 (of weight 1024 each),
7769 * then A0's share of the cpu resource is:
7771 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
7773 * We achieve this by letting init_task_group's tasks sit
7774 * directly in rq->cfs (i.e init_task_group->se[] = NULL).
7776 init_tg_cfs_entry(&init_task_group
, &rq
->cfs
, NULL
, i
, 1, NULL
);
7778 #endif /* CONFIG_FAIR_GROUP_SCHED */
7780 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
7781 #ifdef CONFIG_RT_GROUP_SCHED
7782 INIT_LIST_HEAD(&rq
->leaf_rt_rq_list
);
7783 #ifdef CONFIG_CGROUP_SCHED
7784 init_tg_rt_entry(&init_task_group
, &rq
->rt
, NULL
, i
, 1, NULL
);
7788 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
7789 rq
->cpu_load
[j
] = 0;
7791 rq
->last_load_update_tick
= jiffies
;
7796 rq
->cpu_power
= SCHED_LOAD_SCALE
;
7797 rq
->post_schedule
= 0;
7798 rq
->active_balance
= 0;
7799 rq
->next_balance
= jiffies
;
7804 rq
->avg_idle
= 2*sysctl_sched_migration_cost
;
7805 rq_attach_root(rq
, &def_root_domain
);
7807 rq
->nohz_balance_kick
= 0;
7808 init_sched_softirq_csd(&per_cpu(remote_sched_softirq_cb
, i
));
7812 atomic_set(&rq
->nr_iowait
, 0);
7815 set_load_weight(&init_task
);
7817 #ifdef CONFIG_PREEMPT_NOTIFIERS
7818 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
7822 open_softirq(SCHED_SOFTIRQ
, run_rebalance_domains
);
7825 #ifdef CONFIG_RT_MUTEXES
7826 plist_head_init_raw(&init_task
.pi_waiters
, &init_task
.pi_lock
);
7830 * The boot idle thread does lazy MMU switching as well:
7832 atomic_inc(&init_mm
.mm_count
);
7833 enter_lazy_tlb(&init_mm
, current
);
7836 * Make us the idle thread. Technically, schedule() should not be
7837 * called from this thread, however somewhere below it might be,
7838 * but because we are the idle thread, we just pick up running again
7839 * when this runqueue becomes "idle".
7841 init_idle(current
, smp_processor_id());
7843 calc_load_update
= jiffies
+ LOAD_FREQ
;
7846 * During early bootup we pretend to be a normal task:
7848 current
->sched_class
= &fair_sched_class
;
7850 /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */
7851 zalloc_cpumask_var(&nohz_cpu_mask
, GFP_NOWAIT
);
7854 zalloc_cpumask_var(&nohz
.idle_cpus_mask
, GFP_NOWAIT
);
7855 alloc_cpumask_var(&nohz
.grp_idle_mask
, GFP_NOWAIT
);
7856 atomic_set(&nohz
.load_balancer
, nr_cpu_ids
);
7857 atomic_set(&nohz
.first_pick_cpu
, nr_cpu_ids
);
7858 atomic_set(&nohz
.second_pick_cpu
, nr_cpu_ids
);
7860 /* May be allocated at isolcpus cmdline parse time */
7861 if (cpu_isolated_map
== NULL
)
7862 zalloc_cpumask_var(&cpu_isolated_map
, GFP_NOWAIT
);
7867 scheduler_running
= 1;
7870 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
7871 static inline int preempt_count_equals(int preempt_offset
)
7873 int nested
= (preempt_count() & ~PREEMPT_ACTIVE
) + rcu_preempt_depth();
7875 return (nested
== PREEMPT_INATOMIC_BASE
+ preempt_offset
);
7878 void __might_sleep(const char *file
, int line
, int preempt_offset
)
7881 static unsigned long prev_jiffy
; /* ratelimiting */
7883 if ((preempt_count_equals(preempt_offset
) && !irqs_disabled()) ||
7884 system_state
!= SYSTEM_RUNNING
|| oops_in_progress
)
7886 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
7888 prev_jiffy
= jiffies
;
7891 "BUG: sleeping function called from invalid context at %s:%d\n",
7894 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
7895 in_atomic(), irqs_disabled(),
7896 current
->pid
, current
->comm
);
7898 debug_show_held_locks(current
);
7899 if (irqs_disabled())
7900 print_irqtrace_events(current
);
7904 EXPORT_SYMBOL(__might_sleep
);
7907 #ifdef CONFIG_MAGIC_SYSRQ
7908 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
7912 on_rq
= p
->se
.on_rq
;
7914 deactivate_task(rq
, p
, 0);
7915 __setscheduler(rq
, p
, SCHED_NORMAL
, 0);
7917 activate_task(rq
, p
, 0);
7918 resched_task(rq
->curr
);
7922 void normalize_rt_tasks(void)
7924 struct task_struct
*g
, *p
;
7925 unsigned long flags
;
7928 read_lock_irqsave(&tasklist_lock
, flags
);
7929 do_each_thread(g
, p
) {
7931 * Only normalize user tasks:
7936 p
->se
.exec_start
= 0;
7937 #ifdef CONFIG_SCHEDSTATS
7938 p
->se
.statistics
.wait_start
= 0;
7939 p
->se
.statistics
.sleep_start
= 0;
7940 p
->se
.statistics
.block_start
= 0;
7945 * Renice negative nice level userspace
7948 if (TASK_NICE(p
) < 0 && p
->mm
)
7949 set_user_nice(p
, 0);
7953 raw_spin_lock(&p
->pi_lock
);
7954 rq
= __task_rq_lock(p
);
7956 normalize_task(rq
, p
);
7958 __task_rq_unlock(rq
);
7959 raw_spin_unlock(&p
->pi_lock
);
7960 } while_each_thread(g
, p
);
7962 read_unlock_irqrestore(&tasklist_lock
, flags
);
7965 #endif /* CONFIG_MAGIC_SYSRQ */
7967 #if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
7969 * These functions are only useful for the IA64 MCA handling, or kdb.
7971 * They can only be called when the whole system has been
7972 * stopped - every CPU needs to be quiescent, and no scheduling
7973 * activity can take place. Using them for anything else would
7974 * be a serious bug, and as a result, they aren't even visible
7975 * under any other configuration.
7979 * curr_task - return the current task for a given cpu.
7980 * @cpu: the processor in question.
7982 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7984 struct task_struct
*curr_task(int cpu
)
7986 return cpu_curr(cpu
);
7989 #endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
7993 * set_curr_task - set the current task for a given cpu.
7994 * @cpu: the processor in question.
7995 * @p: the task pointer to set.
7997 * Description: This function must only be used when non-maskable interrupts
7998 * are serviced on a separate stack. It allows the architecture to switch the
7999 * notion of the current task on a cpu in a non-blocking manner. This function
8000 * must be called with all CPU's synchronized, and interrupts disabled, the
8001 * and caller must save the original value of the current task (see
8002 * curr_task() above) and restore that value before reenabling interrupts and
8003 * re-starting the system.
8005 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
8007 void set_curr_task(int cpu
, struct task_struct
*p
)
8014 #ifdef CONFIG_FAIR_GROUP_SCHED
8015 static void free_fair_sched_group(struct task_group
*tg
)
8019 for_each_possible_cpu(i
) {
8021 kfree(tg
->cfs_rq
[i
]);
8031 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8033 struct cfs_rq
*cfs_rq
;
8034 struct sched_entity
*se
;
8038 tg
->cfs_rq
= kzalloc(sizeof(cfs_rq
) * nr_cpu_ids
, GFP_KERNEL
);
8041 tg
->se
= kzalloc(sizeof(se
) * nr_cpu_ids
, GFP_KERNEL
);
8045 tg
->shares
= NICE_0_LOAD
;
8047 for_each_possible_cpu(i
) {
8050 cfs_rq
= kzalloc_node(sizeof(struct cfs_rq
),
8051 GFP_KERNEL
, cpu_to_node(i
));
8055 se
= kzalloc_node(sizeof(struct sched_entity
),
8056 GFP_KERNEL
, cpu_to_node(i
));
8060 init_tg_cfs_entry(tg
, cfs_rq
, se
, i
, 0, parent
->se
[i
]);
8071 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
8073 list_add_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
,
8074 &cpu_rq(cpu
)->leaf_cfs_rq_list
);
8077 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
8079 list_del_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
);
8081 #else /* !CONFG_FAIR_GROUP_SCHED */
8082 static inline void free_fair_sched_group(struct task_group
*tg
)
8087 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8092 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
8096 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
8099 #endif /* CONFIG_FAIR_GROUP_SCHED */
8101 #ifdef CONFIG_RT_GROUP_SCHED
8102 static void free_rt_sched_group(struct task_group
*tg
)
8106 destroy_rt_bandwidth(&tg
->rt_bandwidth
);
8108 for_each_possible_cpu(i
) {
8110 kfree(tg
->rt_rq
[i
]);
8112 kfree(tg
->rt_se
[i
]);
8120 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8122 struct rt_rq
*rt_rq
;
8123 struct sched_rt_entity
*rt_se
;
8127 tg
->rt_rq
= kzalloc(sizeof(rt_rq
) * nr_cpu_ids
, GFP_KERNEL
);
8130 tg
->rt_se
= kzalloc(sizeof(rt_se
) * nr_cpu_ids
, GFP_KERNEL
);
8134 init_rt_bandwidth(&tg
->rt_bandwidth
,
8135 ktime_to_ns(def_rt_bandwidth
.rt_period
), 0);
8137 for_each_possible_cpu(i
) {
8140 rt_rq
= kzalloc_node(sizeof(struct rt_rq
),
8141 GFP_KERNEL
, cpu_to_node(i
));
8145 rt_se
= kzalloc_node(sizeof(struct sched_rt_entity
),
8146 GFP_KERNEL
, cpu_to_node(i
));
8150 init_tg_rt_entry(tg
, rt_rq
, rt_se
, i
, 0, parent
->rt_se
[i
]);
8161 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
8163 list_add_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
,
8164 &cpu_rq(cpu
)->leaf_rt_rq_list
);
8167 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
8169 list_del_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
);
8171 #else /* !CONFIG_RT_GROUP_SCHED */
8172 static inline void free_rt_sched_group(struct task_group
*tg
)
8177 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8182 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
8186 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
8189 #endif /* CONFIG_RT_GROUP_SCHED */
8191 #ifdef CONFIG_CGROUP_SCHED
8192 static void free_sched_group(struct task_group
*tg
)
8194 free_fair_sched_group(tg
);
8195 free_rt_sched_group(tg
);
8199 /* allocate runqueue etc for a new task group */
8200 struct task_group
*sched_create_group(struct task_group
*parent
)
8202 struct task_group
*tg
;
8203 unsigned long flags
;
8206 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
8208 return ERR_PTR(-ENOMEM
);
8210 if (!alloc_fair_sched_group(tg
, parent
))
8213 if (!alloc_rt_sched_group(tg
, parent
))
8216 spin_lock_irqsave(&task_group_lock
, flags
);
8217 for_each_possible_cpu(i
) {
8218 register_fair_sched_group(tg
, i
);
8219 register_rt_sched_group(tg
, i
);
8221 list_add_rcu(&tg
->list
, &task_groups
);
8223 WARN_ON(!parent
); /* root should already exist */
8225 tg
->parent
= parent
;
8226 INIT_LIST_HEAD(&tg
->children
);
8227 list_add_rcu(&tg
->siblings
, &parent
->children
);
8228 spin_unlock_irqrestore(&task_group_lock
, flags
);
8233 free_sched_group(tg
);
8234 return ERR_PTR(-ENOMEM
);
8237 /* rcu callback to free various structures associated with a task group */
8238 static void free_sched_group_rcu(struct rcu_head
*rhp
)
8240 /* now it should be safe to free those cfs_rqs */
8241 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
8244 /* Destroy runqueue etc associated with a task group */
8245 void sched_destroy_group(struct task_group
*tg
)
8247 unsigned long flags
;
8250 spin_lock_irqsave(&task_group_lock
, flags
);
8251 for_each_possible_cpu(i
) {
8252 unregister_fair_sched_group(tg
, i
);
8253 unregister_rt_sched_group(tg
, i
);
8255 list_del_rcu(&tg
->list
);
8256 list_del_rcu(&tg
->siblings
);
8257 spin_unlock_irqrestore(&task_group_lock
, flags
);
8259 /* wait for possible concurrent references to cfs_rqs complete */
8260 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
8263 /* change task's runqueue when it moves between groups.
8264 * The caller of this function should have put the task in its new group
8265 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
8266 * reflect its new group.
8268 void sched_move_task(struct task_struct
*tsk
)
8271 unsigned long flags
;
8274 rq
= task_rq_lock(tsk
, &flags
);
8276 running
= task_current(rq
, tsk
);
8277 on_rq
= tsk
->se
.on_rq
;
8280 dequeue_task(rq
, tsk
, 0);
8281 if (unlikely(running
))
8282 tsk
->sched_class
->put_prev_task(rq
, tsk
);
8284 set_task_rq(tsk
, task_cpu(tsk
));
8286 #ifdef CONFIG_FAIR_GROUP_SCHED
8287 if (tsk
->sched_class
->moved_group
)
8288 tsk
->sched_class
->moved_group(tsk
, on_rq
);
8291 if (unlikely(running
))
8292 tsk
->sched_class
->set_curr_task(rq
);
8294 enqueue_task(rq
, tsk
, 0);
8296 task_rq_unlock(rq
, &flags
);
8298 #endif /* CONFIG_CGROUP_SCHED */
8300 #ifdef CONFIG_FAIR_GROUP_SCHED
8301 static void __set_se_shares(struct sched_entity
*se
, unsigned long shares
)
8303 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
8308 dequeue_entity(cfs_rq
, se
, 0);
8310 se
->load
.weight
= shares
;
8311 se
->load
.inv_weight
= 0;
8314 enqueue_entity(cfs_rq
, se
, 0);
8317 static void set_se_shares(struct sched_entity
*se
, unsigned long shares
)
8319 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
8320 struct rq
*rq
= cfs_rq
->rq
;
8321 unsigned long flags
;
8323 raw_spin_lock_irqsave(&rq
->lock
, flags
);
8324 __set_se_shares(se
, shares
);
8325 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
8328 static DEFINE_MUTEX(shares_mutex
);
8330 int sched_group_set_shares(struct task_group
*tg
, unsigned long shares
)
8333 unsigned long flags
;
8336 * We can't change the weight of the root cgroup.
8341 if (shares
< MIN_SHARES
)
8342 shares
= MIN_SHARES
;
8343 else if (shares
> MAX_SHARES
)
8344 shares
= MAX_SHARES
;
8346 mutex_lock(&shares_mutex
);
8347 if (tg
->shares
== shares
)
8350 spin_lock_irqsave(&task_group_lock
, flags
);
8351 for_each_possible_cpu(i
)
8352 unregister_fair_sched_group(tg
, i
);
8353 list_del_rcu(&tg
->siblings
);
8354 spin_unlock_irqrestore(&task_group_lock
, flags
);
8356 /* wait for any ongoing reference to this group to finish */
8357 synchronize_sched();
8360 * Now we are free to modify the group's share on each cpu
8361 * w/o tripping rebalance_share or load_balance_fair.
8363 tg
->shares
= shares
;
8364 for_each_possible_cpu(i
) {
8368 cfs_rq_set_shares(tg
->cfs_rq
[i
], 0);
8369 set_se_shares(tg
->se
[i
], shares
);
8373 * Enable load balance activity on this group, by inserting it back on
8374 * each cpu's rq->leaf_cfs_rq_list.
8376 spin_lock_irqsave(&task_group_lock
, flags
);
8377 for_each_possible_cpu(i
)
8378 register_fair_sched_group(tg
, i
);
8379 list_add_rcu(&tg
->siblings
, &tg
->parent
->children
);
8380 spin_unlock_irqrestore(&task_group_lock
, flags
);
8382 mutex_unlock(&shares_mutex
);
8386 unsigned long sched_group_shares(struct task_group
*tg
)
8392 #ifdef CONFIG_RT_GROUP_SCHED
8394 * Ensure that the real time constraints are schedulable.
8396 static DEFINE_MUTEX(rt_constraints_mutex
);
8398 static unsigned long to_ratio(u64 period
, u64 runtime
)
8400 if (runtime
== RUNTIME_INF
)
8403 return div64_u64(runtime
<< 20, period
);
8406 /* Must be called with tasklist_lock held */
8407 static inline int tg_has_rt_tasks(struct task_group
*tg
)
8409 struct task_struct
*g
, *p
;
8411 do_each_thread(g
, p
) {
8412 if (rt_task(p
) && rt_rq_of_se(&p
->rt
)->tg
== tg
)
8414 } while_each_thread(g
, p
);
8419 struct rt_schedulable_data
{
8420 struct task_group
*tg
;
8425 static int tg_schedulable(struct task_group
*tg
, void *data
)
8427 struct rt_schedulable_data
*d
= data
;
8428 struct task_group
*child
;
8429 unsigned long total
, sum
= 0;
8430 u64 period
, runtime
;
8432 period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8433 runtime
= tg
->rt_bandwidth
.rt_runtime
;
8436 period
= d
->rt_period
;
8437 runtime
= d
->rt_runtime
;
8441 * Cannot have more runtime than the period.
8443 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
8447 * Ensure we don't starve existing RT tasks.
8449 if (rt_bandwidth_enabled() && !runtime
&& tg_has_rt_tasks(tg
))
8452 total
= to_ratio(period
, runtime
);
8455 * Nobody can have more than the global setting allows.
8457 if (total
> to_ratio(global_rt_period(), global_rt_runtime()))
8461 * The sum of our children's runtime should not exceed our own.
8463 list_for_each_entry_rcu(child
, &tg
->children
, siblings
) {
8464 period
= ktime_to_ns(child
->rt_bandwidth
.rt_period
);
8465 runtime
= child
->rt_bandwidth
.rt_runtime
;
8467 if (child
== d
->tg
) {
8468 period
= d
->rt_period
;
8469 runtime
= d
->rt_runtime
;
8472 sum
+= to_ratio(period
, runtime
);
8481 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
8483 struct rt_schedulable_data data
= {
8485 .rt_period
= period
,
8486 .rt_runtime
= runtime
,
8489 return walk_tg_tree(tg_schedulable
, tg_nop
, &data
);
8492 static int tg_set_bandwidth(struct task_group
*tg
,
8493 u64 rt_period
, u64 rt_runtime
)
8497 mutex_lock(&rt_constraints_mutex
);
8498 read_lock(&tasklist_lock
);
8499 err
= __rt_schedulable(tg
, rt_period
, rt_runtime
);
8503 raw_spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
8504 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
8505 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
8507 for_each_possible_cpu(i
) {
8508 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
8510 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
8511 rt_rq
->rt_runtime
= rt_runtime
;
8512 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
8514 raw_spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
8516 read_unlock(&tasklist_lock
);
8517 mutex_unlock(&rt_constraints_mutex
);
8522 int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
8524 u64 rt_runtime
, rt_period
;
8526 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8527 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
8528 if (rt_runtime_us
< 0)
8529 rt_runtime
= RUNTIME_INF
;
8531 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
8534 long sched_group_rt_runtime(struct task_group
*tg
)
8538 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
8541 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
8542 do_div(rt_runtime_us
, NSEC_PER_USEC
);
8543 return rt_runtime_us
;
8546 int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
8548 u64 rt_runtime
, rt_period
;
8550 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
8551 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
8556 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
8559 long sched_group_rt_period(struct task_group
*tg
)
8563 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8564 do_div(rt_period_us
, NSEC_PER_USEC
);
8565 return rt_period_us
;
8568 static int sched_rt_global_constraints(void)
8570 u64 runtime
, period
;
8573 if (sysctl_sched_rt_period
<= 0)
8576 runtime
= global_rt_runtime();
8577 period
= global_rt_period();
8580 * Sanity check on the sysctl variables.
8582 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
8585 mutex_lock(&rt_constraints_mutex
);
8586 read_lock(&tasklist_lock
);
8587 ret
= __rt_schedulable(NULL
, 0, 0);
8588 read_unlock(&tasklist_lock
);
8589 mutex_unlock(&rt_constraints_mutex
);
8594 int sched_rt_can_attach(struct task_group
*tg
, struct task_struct
*tsk
)
8596 /* Don't accept realtime tasks when there is no way for them to run */
8597 if (rt_task(tsk
) && tg
->rt_bandwidth
.rt_runtime
== 0)
8603 #else /* !CONFIG_RT_GROUP_SCHED */
8604 static int sched_rt_global_constraints(void)
8606 unsigned long flags
;
8609 if (sysctl_sched_rt_period
<= 0)
8613 * There's always some RT tasks in the root group
8614 * -- migration, kstopmachine etc..
8616 if (sysctl_sched_rt_runtime
== 0)
8619 raw_spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
8620 for_each_possible_cpu(i
) {
8621 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
8623 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
8624 rt_rq
->rt_runtime
= global_rt_runtime();
8625 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
8627 raw_spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
8631 #endif /* CONFIG_RT_GROUP_SCHED */
8633 int sched_rt_handler(struct ctl_table
*table
, int write
,
8634 void __user
*buffer
, size_t *lenp
,
8638 int old_period
, old_runtime
;
8639 static DEFINE_MUTEX(mutex
);
8642 old_period
= sysctl_sched_rt_period
;
8643 old_runtime
= sysctl_sched_rt_runtime
;
8645 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
8647 if (!ret
&& write
) {
8648 ret
= sched_rt_global_constraints();
8650 sysctl_sched_rt_period
= old_period
;
8651 sysctl_sched_rt_runtime
= old_runtime
;
8653 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
8654 def_rt_bandwidth
.rt_period
=
8655 ns_to_ktime(global_rt_period());
8658 mutex_unlock(&mutex
);
8663 #ifdef CONFIG_CGROUP_SCHED
8665 /* return corresponding task_group object of a cgroup */
8666 static inline struct task_group
*cgroup_tg(struct cgroup
*cgrp
)
8668 return container_of(cgroup_subsys_state(cgrp
, cpu_cgroup_subsys_id
),
8669 struct task_group
, css
);
8672 static struct cgroup_subsys_state
*
8673 cpu_cgroup_create(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8675 struct task_group
*tg
, *parent
;
8677 if (!cgrp
->parent
) {
8678 /* This is early initialization for the top cgroup */
8679 return &init_task_group
.css
;
8682 parent
= cgroup_tg(cgrp
->parent
);
8683 tg
= sched_create_group(parent
);
8685 return ERR_PTR(-ENOMEM
);
8691 cpu_cgroup_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8693 struct task_group
*tg
= cgroup_tg(cgrp
);
8695 sched_destroy_group(tg
);
8699 cpu_cgroup_can_attach_task(struct cgroup
*cgrp
, struct task_struct
*tsk
)
8701 #ifdef CONFIG_RT_GROUP_SCHED
8702 if (!sched_rt_can_attach(cgroup_tg(cgrp
), tsk
))
8705 /* We don't support RT-tasks being in separate groups */
8706 if (tsk
->sched_class
!= &fair_sched_class
)
8713 cpu_cgroup_can_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
8714 struct task_struct
*tsk
, bool threadgroup
)
8716 int retval
= cpu_cgroup_can_attach_task(cgrp
, tsk
);
8720 struct task_struct
*c
;
8722 list_for_each_entry_rcu(c
, &tsk
->thread_group
, thread_group
) {
8723 retval
= cpu_cgroup_can_attach_task(cgrp
, c
);
8735 cpu_cgroup_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
8736 struct cgroup
*old_cont
, struct task_struct
*tsk
,
8739 sched_move_task(tsk
);
8741 struct task_struct
*c
;
8743 list_for_each_entry_rcu(c
, &tsk
->thread_group
, thread_group
) {
8750 #ifdef CONFIG_FAIR_GROUP_SCHED
8751 static int cpu_shares_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
8754 return sched_group_set_shares(cgroup_tg(cgrp
), shareval
);
8757 static u64
cpu_shares_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
8759 struct task_group
*tg
= cgroup_tg(cgrp
);
8761 return (u64
) tg
->shares
;
8763 #endif /* CONFIG_FAIR_GROUP_SCHED */
8765 #ifdef CONFIG_RT_GROUP_SCHED
8766 static int cpu_rt_runtime_write(struct cgroup
*cgrp
, struct cftype
*cft
,
8769 return sched_group_set_rt_runtime(cgroup_tg(cgrp
), val
);
8772 static s64
cpu_rt_runtime_read(struct cgroup
*cgrp
, struct cftype
*cft
)
8774 return sched_group_rt_runtime(cgroup_tg(cgrp
));
8777 static int cpu_rt_period_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
8780 return sched_group_set_rt_period(cgroup_tg(cgrp
), rt_period_us
);
8783 static u64
cpu_rt_period_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
8785 return sched_group_rt_period(cgroup_tg(cgrp
));
8787 #endif /* CONFIG_RT_GROUP_SCHED */
8789 static struct cftype cpu_files
[] = {
8790 #ifdef CONFIG_FAIR_GROUP_SCHED
8793 .read_u64
= cpu_shares_read_u64
,
8794 .write_u64
= cpu_shares_write_u64
,
8797 #ifdef CONFIG_RT_GROUP_SCHED
8799 .name
= "rt_runtime_us",
8800 .read_s64
= cpu_rt_runtime_read
,
8801 .write_s64
= cpu_rt_runtime_write
,
8804 .name
= "rt_period_us",
8805 .read_u64
= cpu_rt_period_read_uint
,
8806 .write_u64
= cpu_rt_period_write_uint
,
8811 static int cpu_cgroup_populate(struct cgroup_subsys
*ss
, struct cgroup
*cont
)
8813 return cgroup_add_files(cont
, ss
, cpu_files
, ARRAY_SIZE(cpu_files
));
8816 struct cgroup_subsys cpu_cgroup_subsys
= {
8818 .create
= cpu_cgroup_create
,
8819 .destroy
= cpu_cgroup_destroy
,
8820 .can_attach
= cpu_cgroup_can_attach
,
8821 .attach
= cpu_cgroup_attach
,
8822 .populate
= cpu_cgroup_populate
,
8823 .subsys_id
= cpu_cgroup_subsys_id
,
8827 #endif /* CONFIG_CGROUP_SCHED */
8829 #ifdef CONFIG_CGROUP_CPUACCT
8832 * CPU accounting code for task groups.
8834 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
8835 * (balbir@in.ibm.com).
8838 /* track cpu usage of a group of tasks and its child groups */
8840 struct cgroup_subsys_state css
;
8841 /* cpuusage holds pointer to a u64-type object on every cpu */
8842 u64 __percpu
*cpuusage
;
8843 struct percpu_counter cpustat
[CPUACCT_STAT_NSTATS
];
8844 struct cpuacct
*parent
;
8847 struct cgroup_subsys cpuacct_subsys
;
8849 /* return cpu accounting group corresponding to this container */
8850 static inline struct cpuacct
*cgroup_ca(struct cgroup
*cgrp
)
8852 return container_of(cgroup_subsys_state(cgrp
, cpuacct_subsys_id
),
8853 struct cpuacct
, css
);
8856 /* return cpu accounting group to which this task belongs */
8857 static inline struct cpuacct
*task_ca(struct task_struct
*tsk
)
8859 return container_of(task_subsys_state(tsk
, cpuacct_subsys_id
),
8860 struct cpuacct
, css
);
8863 /* create a new cpu accounting group */
8864 static struct cgroup_subsys_state
*cpuacct_create(
8865 struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8867 struct cpuacct
*ca
= kzalloc(sizeof(*ca
), GFP_KERNEL
);
8873 ca
->cpuusage
= alloc_percpu(u64
);
8877 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++)
8878 if (percpu_counter_init(&ca
->cpustat
[i
], 0))
8879 goto out_free_counters
;
8882 ca
->parent
= cgroup_ca(cgrp
->parent
);
8888 percpu_counter_destroy(&ca
->cpustat
[i
]);
8889 free_percpu(ca
->cpuusage
);
8893 return ERR_PTR(-ENOMEM
);
8896 /* destroy an existing cpu accounting group */
8898 cpuacct_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8900 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8903 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++)
8904 percpu_counter_destroy(&ca
->cpustat
[i
]);
8905 free_percpu(ca
->cpuusage
);
8909 static u64
cpuacct_cpuusage_read(struct cpuacct
*ca
, int cpu
)
8911 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
8914 #ifndef CONFIG_64BIT
8916 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
8918 raw_spin_lock_irq(&cpu_rq(cpu
)->lock
);
8920 raw_spin_unlock_irq(&cpu_rq(cpu
)->lock
);
8928 static void cpuacct_cpuusage_write(struct cpuacct
*ca
, int cpu
, u64 val
)
8930 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
8932 #ifndef CONFIG_64BIT
8934 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
8936 raw_spin_lock_irq(&cpu_rq(cpu
)->lock
);
8938 raw_spin_unlock_irq(&cpu_rq(cpu
)->lock
);
8944 /* return total cpu usage (in nanoseconds) of a group */
8945 static u64
cpuusage_read(struct cgroup
*cgrp
, struct cftype
*cft
)
8947 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8948 u64 totalcpuusage
= 0;
8951 for_each_present_cpu(i
)
8952 totalcpuusage
+= cpuacct_cpuusage_read(ca
, i
);
8954 return totalcpuusage
;
8957 static int cpuusage_write(struct cgroup
*cgrp
, struct cftype
*cftype
,
8960 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8969 for_each_present_cpu(i
)
8970 cpuacct_cpuusage_write(ca
, i
, 0);
8976 static int cpuacct_percpu_seq_read(struct cgroup
*cgroup
, struct cftype
*cft
,
8979 struct cpuacct
*ca
= cgroup_ca(cgroup
);
8983 for_each_present_cpu(i
) {
8984 percpu
= cpuacct_cpuusage_read(ca
, i
);
8985 seq_printf(m
, "%llu ", (unsigned long long) percpu
);
8987 seq_printf(m
, "\n");
8991 static const char *cpuacct_stat_desc
[] = {
8992 [CPUACCT_STAT_USER
] = "user",
8993 [CPUACCT_STAT_SYSTEM
] = "system",
8996 static int cpuacct_stats_show(struct cgroup
*cgrp
, struct cftype
*cft
,
8997 struct cgroup_map_cb
*cb
)
8999 struct cpuacct
*ca
= cgroup_ca(cgrp
);
9002 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++) {
9003 s64 val
= percpu_counter_read(&ca
->cpustat
[i
]);
9004 val
= cputime64_to_clock_t(val
);
9005 cb
->fill(cb
, cpuacct_stat_desc
[i
], val
);
9010 static struct cftype files
[] = {
9013 .read_u64
= cpuusage_read
,
9014 .write_u64
= cpuusage_write
,
9017 .name
= "usage_percpu",
9018 .read_seq_string
= cpuacct_percpu_seq_read
,
9022 .read_map
= cpuacct_stats_show
,
9026 static int cpuacct_populate(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9028 return cgroup_add_files(cgrp
, ss
, files
, ARRAY_SIZE(files
));
9032 * charge this task's execution time to its accounting group.
9034 * called with rq->lock held.
9036 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
)
9041 if (unlikely(!cpuacct_subsys
.active
))
9044 cpu
= task_cpu(tsk
);
9050 for (; ca
; ca
= ca
->parent
) {
9051 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
9052 *cpuusage
+= cputime
;
9059 * When CONFIG_VIRT_CPU_ACCOUNTING is enabled one jiffy can be very large
9060 * in cputime_t units. As a result, cpuacct_update_stats calls
9061 * percpu_counter_add with values large enough to always overflow the
9062 * per cpu batch limit causing bad SMP scalability.
9064 * To fix this we scale percpu_counter_batch by cputime_one_jiffy so we
9065 * batch the same amount of time with CONFIG_VIRT_CPU_ACCOUNTING disabled
9066 * and enabled. We cap it at INT_MAX which is the largest allowed batch value.
9069 #define CPUACCT_BATCH \
9070 min_t(long, percpu_counter_batch * cputime_one_jiffy, INT_MAX)
9072 #define CPUACCT_BATCH 0
9076 * Charge the system/user time to the task's accounting group.
9078 static void cpuacct_update_stats(struct task_struct
*tsk
,
9079 enum cpuacct_stat_index idx
, cputime_t val
)
9082 int batch
= CPUACCT_BATCH
;
9084 if (unlikely(!cpuacct_subsys
.active
))
9091 __percpu_counter_add(&ca
->cpustat
[idx
], val
, batch
);
9097 struct cgroup_subsys cpuacct_subsys
= {
9099 .create
= cpuacct_create
,
9100 .destroy
= cpuacct_destroy
,
9101 .populate
= cpuacct_populate
,
9102 .subsys_id
= cpuacct_subsys_id
,
9104 #endif /* CONFIG_CGROUP_CPUACCT */
9108 void synchronize_sched_expedited(void)
9112 EXPORT_SYMBOL_GPL(synchronize_sched_expedited
);
9114 #else /* #ifndef CONFIG_SMP */
9116 static atomic_t synchronize_sched_expedited_count
= ATOMIC_INIT(0);
9118 static int synchronize_sched_expedited_cpu_stop(void *data
)
9121 * There must be a full memory barrier on each affected CPU
9122 * between the time that try_stop_cpus() is called and the
9123 * time that it returns.
9125 * In the current initial implementation of cpu_stop, the
9126 * above condition is already met when the control reaches
9127 * this point and the following smp_mb() is not strictly
9128 * necessary. Do smp_mb() anyway for documentation and
9129 * robustness against future implementation changes.
9131 smp_mb(); /* See above comment block. */
9136 * Wait for an rcu-sched grace period to elapse, but use "big hammer"
9137 * approach to force grace period to end quickly. This consumes
9138 * significant time on all CPUs, and is thus not recommended for
9139 * any sort of common-case code.
9141 * Note that it is illegal to call this function while holding any
9142 * lock that is acquired by a CPU-hotplug notifier. Failing to
9143 * observe this restriction will result in deadlock.
9145 void synchronize_sched_expedited(void)
9147 int snap
, trycount
= 0;
9149 smp_mb(); /* ensure prior mod happens before capturing snap. */
9150 snap
= atomic_read(&synchronize_sched_expedited_count
) + 1;
9152 while (try_stop_cpus(cpu_online_mask
,
9153 synchronize_sched_expedited_cpu_stop
,
9156 if (trycount
++ < 10)
9157 udelay(trycount
* num_online_cpus());
9159 synchronize_sched();
9162 if (atomic_read(&synchronize_sched_expedited_count
) - snap
> 0) {
9163 smp_mb(); /* ensure test happens before caller kfree */
9168 atomic_inc(&synchronize_sched_expedited_count
);
9169 smp_mb__after_atomic_inc(); /* ensure post-GP actions seen after GP. */
9172 EXPORT_SYMBOL_GPL(synchronize_sched_expedited
);
9174 #endif /* #else #ifndef CONFIG_SMP */