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>
78 #include <asm/mutex.h>
80 #include "sched_cpupri.h"
81 #include "workqueue_sched.h"
82 #include "sched_autogroup.h"
84 #define CREATE_TRACE_POINTS
85 #include <trace/events/sched.h>
88 * Convert user-nice values [ -20 ... 0 ... 19 ]
89 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
92 #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
93 #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
94 #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
97 * 'User priority' is the nice value converted to something we
98 * can work with better when scaling various scheduler parameters,
99 * it's a [ 0 ... 39 ] range.
101 #define USER_PRIO(p) ((p)-MAX_RT_PRIO)
102 #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
103 #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
106 * Helpers for converting nanosecond timing to jiffy resolution
108 #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
110 #define NICE_0_LOAD SCHED_LOAD_SCALE
111 #define NICE_0_SHIFT SCHED_LOAD_SHIFT
114 * These are the 'tuning knobs' of the scheduler:
116 * default timeslice is 100 msecs (used only for SCHED_RR tasks).
117 * Timeslices get refilled after they expire.
119 #define DEF_TIMESLICE (100 * HZ / 1000)
122 * single value that denotes runtime == period, ie unlimited time.
124 #define RUNTIME_INF ((u64)~0ULL)
126 static inline int rt_policy(int policy
)
128 if (unlikely(policy
== SCHED_FIFO
|| policy
== SCHED_RR
))
133 static inline int task_has_rt_policy(struct task_struct
*p
)
135 return rt_policy(p
->policy
);
139 * This is the priority-queue data structure of the RT scheduling class:
141 struct rt_prio_array
{
142 DECLARE_BITMAP(bitmap
, MAX_RT_PRIO
+1); /* include 1 bit for delimiter */
143 struct list_head queue
[MAX_RT_PRIO
];
146 struct rt_bandwidth
{
147 /* nests inside the rq lock: */
148 raw_spinlock_t rt_runtime_lock
;
151 struct hrtimer rt_period_timer
;
154 static struct rt_bandwidth def_rt_bandwidth
;
156 static int do_sched_rt_period_timer(struct rt_bandwidth
*rt_b
, int overrun
);
158 static enum hrtimer_restart
sched_rt_period_timer(struct hrtimer
*timer
)
160 struct rt_bandwidth
*rt_b
=
161 container_of(timer
, struct rt_bandwidth
, rt_period_timer
);
167 now
= hrtimer_cb_get_time(timer
);
168 overrun
= hrtimer_forward(timer
, now
, rt_b
->rt_period
);
173 idle
= do_sched_rt_period_timer(rt_b
, overrun
);
176 return idle
? HRTIMER_NORESTART
: HRTIMER_RESTART
;
180 void init_rt_bandwidth(struct rt_bandwidth
*rt_b
, u64 period
, u64 runtime
)
182 rt_b
->rt_period
= ns_to_ktime(period
);
183 rt_b
->rt_runtime
= runtime
;
185 raw_spin_lock_init(&rt_b
->rt_runtime_lock
);
187 hrtimer_init(&rt_b
->rt_period_timer
,
188 CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
189 rt_b
->rt_period_timer
.function
= sched_rt_period_timer
;
192 static inline int rt_bandwidth_enabled(void)
194 return sysctl_sched_rt_runtime
>= 0;
197 static void start_rt_bandwidth(struct rt_bandwidth
*rt_b
)
201 if (!rt_bandwidth_enabled() || rt_b
->rt_runtime
== RUNTIME_INF
)
204 if (hrtimer_active(&rt_b
->rt_period_timer
))
207 raw_spin_lock(&rt_b
->rt_runtime_lock
);
212 if (hrtimer_active(&rt_b
->rt_period_timer
))
215 now
= hrtimer_cb_get_time(&rt_b
->rt_period_timer
);
216 hrtimer_forward(&rt_b
->rt_period_timer
, now
, rt_b
->rt_period
);
218 soft
= hrtimer_get_softexpires(&rt_b
->rt_period_timer
);
219 hard
= hrtimer_get_expires(&rt_b
->rt_period_timer
);
220 delta
= ktime_to_ns(ktime_sub(hard
, soft
));
221 __hrtimer_start_range_ns(&rt_b
->rt_period_timer
, soft
, delta
,
222 HRTIMER_MODE_ABS_PINNED
, 0);
224 raw_spin_unlock(&rt_b
->rt_runtime_lock
);
227 #ifdef CONFIG_RT_GROUP_SCHED
228 static void destroy_rt_bandwidth(struct rt_bandwidth
*rt_b
)
230 hrtimer_cancel(&rt_b
->rt_period_timer
);
235 * sched_domains_mutex serializes calls to arch_init_sched_domains,
236 * detach_destroy_domains and partition_sched_domains.
238 static DEFINE_MUTEX(sched_domains_mutex
);
240 #ifdef CONFIG_CGROUP_SCHED
242 #include <linux/cgroup.h>
246 static LIST_HEAD(task_groups
);
248 /* task group related information */
250 struct cgroup_subsys_state css
;
252 #ifdef CONFIG_FAIR_GROUP_SCHED
253 /* schedulable entities of this group on each cpu */
254 struct sched_entity
**se
;
255 /* runqueue "owned" by this group on each cpu */
256 struct cfs_rq
**cfs_rq
;
257 unsigned long shares
;
259 atomic_t load_weight
;
262 #ifdef CONFIG_RT_GROUP_SCHED
263 struct sched_rt_entity
**rt_se
;
264 struct rt_rq
**rt_rq
;
266 struct rt_bandwidth rt_bandwidth
;
270 struct list_head list
;
272 struct task_group
*parent
;
273 struct list_head siblings
;
274 struct list_head children
;
276 #ifdef CONFIG_SCHED_AUTOGROUP
277 struct autogroup
*autogroup
;
281 #define root_task_group init_task_group
283 /* task_group_lock serializes the addition/removal of task groups */
284 static DEFINE_SPINLOCK(task_group_lock
);
286 #ifdef CONFIG_FAIR_GROUP_SCHED
288 # define INIT_TASK_GROUP_LOAD NICE_0_LOAD
291 * A weight of 0 or 1 can cause arithmetics problems.
292 * A weight of a cfs_rq is the sum of weights of which entities
293 * are queued on this cfs_rq, so a weight of a entity should not be
294 * too large, so as the shares value of a task group.
295 * (The default weight is 1024 - so there's no practical
296 * limitation from this.)
299 #define MAX_SHARES (1UL << 18)
301 static int init_task_group_load
= INIT_TASK_GROUP_LOAD
;
304 /* Default task group.
305 * Every task in system belong to this group at bootup.
307 struct task_group init_task_group
;
309 #endif /* CONFIG_CGROUP_SCHED */
311 /* CFS-related fields in a runqueue */
313 struct load_weight load
;
314 unsigned long nr_running
;
319 struct rb_root tasks_timeline
;
320 struct rb_node
*rb_leftmost
;
322 struct list_head tasks
;
323 struct list_head
*balance_iterator
;
326 * 'curr' points to currently running entity on this cfs_rq.
327 * It is set to NULL otherwise (i.e when none are currently running).
329 struct sched_entity
*curr
, *next
, *last
;
331 unsigned int nr_spread_over
;
333 #ifdef CONFIG_FAIR_GROUP_SCHED
334 struct rq
*rq
; /* cpu runqueue to which this cfs_rq is attached */
337 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
338 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
339 * (like users, containers etc.)
341 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
342 * 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 * Maintaining per-cpu shares distribution for group scheduling
365 * load_stamp is the last time we updated the load average
366 * load_last is the last time we updated the load average and saw load
367 * load_unacc_exec_time is currently unaccounted execution time
371 u64 load_stamp
, load_last
, load_unacc_exec_time
;
373 unsigned long load_contribution
;
378 /* Real-Time classes' related field in a runqueue: */
380 struct rt_prio_array active
;
381 unsigned long rt_nr_running
;
382 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
384 int curr
; /* highest queued rt task prio */
386 int next
; /* next highest */
391 unsigned long rt_nr_migratory
;
392 unsigned long rt_nr_total
;
394 struct plist_head pushable_tasks
;
399 /* Nests inside the rq lock: */
400 raw_spinlock_t rt_runtime_lock
;
402 #ifdef CONFIG_RT_GROUP_SCHED
403 unsigned long rt_nr_boosted
;
406 struct list_head leaf_rt_rq_list
;
407 struct task_group
*tg
;
414 * We add the notion of a root-domain which will be used to define per-domain
415 * variables. Each exclusive cpuset essentially defines an island domain by
416 * fully partitioning the member cpus from any other cpuset. Whenever a new
417 * exclusive cpuset is created, we also create and attach a new root-domain
424 cpumask_var_t online
;
427 * The "RT overload" flag: it gets set if a CPU has more than
428 * one runnable RT task.
430 cpumask_var_t rto_mask
;
432 struct cpupri cpupri
;
436 * By default the system creates a single root-domain with all cpus as
437 * members (mimicking the global state we have today).
439 static struct root_domain def_root_domain
;
441 #endif /* CONFIG_SMP */
444 * This is the main, per-CPU runqueue data structure.
446 * Locking rule: those places that want to lock multiple runqueues
447 * (such as the load balancing or the thread migration code), lock
448 * acquire operations must be ordered by ascending &runqueue.
455 * nr_running and cpu_load should be in the same cacheline because
456 * remote CPUs use both these fields when doing load calculation.
458 unsigned long nr_running
;
459 #define CPU_LOAD_IDX_MAX 5
460 unsigned long cpu_load
[CPU_LOAD_IDX_MAX
];
461 unsigned long last_load_update_tick
;
464 unsigned char nohz_balance_kick
;
466 unsigned int skip_clock_update
;
468 /* capture load from *all* tasks on this cpu: */
469 struct load_weight load
;
470 unsigned long nr_load_updates
;
476 #ifdef CONFIG_FAIR_GROUP_SCHED
477 /* list of leaf cfs_rq on this cpu: */
478 struct list_head leaf_cfs_rq_list
;
480 #ifdef CONFIG_RT_GROUP_SCHED
481 struct list_head leaf_rt_rq_list
;
485 * This is part of a global counter where only the total sum
486 * over all CPUs matters. A task can increase this counter on
487 * one CPU and if it got migrated afterwards it may decrease
488 * it on another CPU. Always updated under the runqueue lock:
490 unsigned long nr_uninterruptible
;
492 struct task_struct
*curr
, *idle
, *stop
;
493 unsigned long next_balance
;
494 struct mm_struct
*prev_mm
;
502 struct root_domain
*rd
;
503 struct sched_domain
*sd
;
505 unsigned long cpu_power
;
507 unsigned char idle_at_tick
;
508 /* For active balancing */
512 struct cpu_stop_work active_balance_work
;
513 /* cpu of this runqueue: */
517 unsigned long avg_load_per_task
;
525 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
529 /* calc_load related fields */
530 unsigned long calc_load_update
;
531 long calc_load_active
;
533 #ifdef CONFIG_SCHED_HRTICK
535 int hrtick_csd_pending
;
536 struct call_single_data hrtick_csd
;
538 struct hrtimer hrtick_timer
;
541 #ifdef CONFIG_SCHEDSTATS
543 struct sched_info rq_sched_info
;
544 unsigned long long rq_cpu_time
;
545 /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
547 /* sys_sched_yield() stats */
548 unsigned int yld_count
;
550 /* schedule() stats */
551 unsigned int sched_switch
;
552 unsigned int sched_count
;
553 unsigned int sched_goidle
;
555 /* try_to_wake_up() stats */
556 unsigned int ttwu_count
;
557 unsigned int ttwu_local
;
560 unsigned int bkl_count
;
564 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
567 static void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int flags
);
569 static inline int cpu_of(struct rq
*rq
)
578 #define rcu_dereference_check_sched_domain(p) \
579 rcu_dereference_check((p), \
580 rcu_read_lock_sched_held() || \
581 lockdep_is_held(&sched_domains_mutex))
584 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
585 * See detach_destroy_domains: synchronize_sched for details.
587 * The domain tree of any CPU may only be accessed from within
588 * preempt-disabled sections.
590 #define for_each_domain(cpu, __sd) \
591 for (__sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
593 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
594 #define this_rq() (&__get_cpu_var(runqueues))
595 #define task_rq(p) cpu_rq(task_cpu(p))
596 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
597 #define raw_rq() (&__raw_get_cpu_var(runqueues))
599 #ifdef CONFIG_CGROUP_SCHED
602 * Return the group to which this tasks belongs.
604 * We use task_subsys_state_check() and extend the RCU verification
605 * with lockdep_is_held(&task_rq(p)->lock) because cpu_cgroup_attach()
606 * holds that lock for each task it moves into the cgroup. Therefore
607 * by holding that lock, we pin the task to the current cgroup.
609 static inline struct task_group
*task_group(struct task_struct
*p
)
611 struct task_group
*tg
;
612 struct cgroup_subsys_state
*css
;
614 css
= task_subsys_state_check(p
, cpu_cgroup_subsys_id
,
615 lockdep_is_held(&task_rq(p
)->lock
));
616 tg
= container_of(css
, struct task_group
, css
);
618 return autogroup_task_group(p
, tg
);
621 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
622 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
)
624 #ifdef CONFIG_FAIR_GROUP_SCHED
625 p
->se
.cfs_rq
= task_group(p
)->cfs_rq
[cpu
];
626 p
->se
.parent
= task_group(p
)->se
[cpu
];
629 #ifdef CONFIG_RT_GROUP_SCHED
630 p
->rt
.rt_rq
= task_group(p
)->rt_rq
[cpu
];
631 p
->rt
.parent
= task_group(p
)->rt_se
[cpu
];
635 #else /* CONFIG_CGROUP_SCHED */
637 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
) { }
638 static inline struct task_group
*task_group(struct task_struct
*p
)
643 #endif /* CONFIG_CGROUP_SCHED */
645 static u64
irq_time_cpu(int cpu
);
646 static void sched_irq_time_avg_update(struct rq
*rq
, u64 irq_time
);
648 inline void update_rq_clock(struct rq
*rq
)
650 if (!rq
->skip_clock_update
) {
651 int cpu
= cpu_of(rq
);
654 rq
->clock
= sched_clock_cpu(cpu
);
655 irq_time
= irq_time_cpu(cpu
);
656 if (rq
->clock
- irq_time
> rq
->clock_task
)
657 rq
->clock_task
= rq
->clock
- irq_time
;
659 sched_irq_time_avg_update(rq
, irq_time
);
664 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
666 #ifdef CONFIG_SCHED_DEBUG
667 # define const_debug __read_mostly
669 # define const_debug static const
674 * @cpu: the processor in question.
676 * Returns true if the current cpu runqueue is locked.
677 * This interface allows printk to be called with the runqueue lock
678 * held and know whether or not it is OK to wake up the klogd.
680 int runqueue_is_locked(int cpu
)
682 return raw_spin_is_locked(&cpu_rq(cpu
)->lock
);
686 * Debugging: various feature bits
689 #define SCHED_FEAT(name, enabled) \
690 __SCHED_FEAT_##name ,
693 #include "sched_features.h"
698 #define SCHED_FEAT(name, enabled) \
699 (1UL << __SCHED_FEAT_##name) * enabled |
701 const_debug
unsigned int sysctl_sched_features
=
702 #include "sched_features.h"
707 #ifdef CONFIG_SCHED_DEBUG
708 #define SCHED_FEAT(name, enabled) \
711 static __read_mostly
char *sched_feat_names
[] = {
712 #include "sched_features.h"
718 static int sched_feat_show(struct seq_file
*m
, void *v
)
722 for (i
= 0; sched_feat_names
[i
]; i
++) {
723 if (!(sysctl_sched_features
& (1UL << i
)))
725 seq_printf(m
, "%s ", sched_feat_names
[i
]);
733 sched_feat_write(struct file
*filp
, const char __user
*ubuf
,
734 size_t cnt
, loff_t
*ppos
)
744 if (copy_from_user(&buf
, ubuf
, cnt
))
750 if (strncmp(buf
, "NO_", 3) == 0) {
755 for (i
= 0; sched_feat_names
[i
]; i
++) {
756 if (strcmp(cmp
, sched_feat_names
[i
]) == 0) {
758 sysctl_sched_features
&= ~(1UL << i
);
760 sysctl_sched_features
|= (1UL << i
);
765 if (!sched_feat_names
[i
])
773 static int sched_feat_open(struct inode
*inode
, struct file
*filp
)
775 return single_open(filp
, sched_feat_show
, NULL
);
778 static const struct file_operations sched_feat_fops
= {
779 .open
= sched_feat_open
,
780 .write
= sched_feat_write
,
783 .release
= single_release
,
786 static __init
int sched_init_debug(void)
788 debugfs_create_file("sched_features", 0644, NULL
, NULL
,
793 late_initcall(sched_init_debug
);
797 #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
800 * Number of tasks to iterate in a single balance run.
801 * Limited because this is done with IRQs disabled.
803 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
806 * period over which we average the RT time consumption, measured
811 const_debug
unsigned int sysctl_sched_time_avg
= MSEC_PER_SEC
;
814 * period over which we measure -rt task cpu usage in us.
817 unsigned int sysctl_sched_rt_period
= 1000000;
819 static __read_mostly
int scheduler_running
;
822 * part of the period that we allow rt tasks to run in us.
825 int sysctl_sched_rt_runtime
= 950000;
827 static inline u64
global_rt_period(void)
829 return (u64
)sysctl_sched_rt_period
* NSEC_PER_USEC
;
832 static inline u64
global_rt_runtime(void)
834 if (sysctl_sched_rt_runtime
< 0)
837 return (u64
)sysctl_sched_rt_runtime
* NSEC_PER_USEC
;
840 #ifndef prepare_arch_switch
841 # define prepare_arch_switch(next) do { } while (0)
843 #ifndef finish_arch_switch
844 # define finish_arch_switch(prev) do { } while (0)
847 static inline int task_current(struct rq
*rq
, struct task_struct
*p
)
849 return rq
->curr
== p
;
852 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
853 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
855 return task_current(rq
, p
);
858 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
862 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
864 #ifdef CONFIG_DEBUG_SPINLOCK
865 /* this is a valid case when another task releases the spinlock */
866 rq
->lock
.owner
= current
;
869 * If we are tracking spinlock dependencies then we have to
870 * fix up the runqueue lock - which gets 'carried over' from
873 spin_acquire(&rq
->lock
.dep_map
, 0, 0, _THIS_IP_
);
875 raw_spin_unlock_irq(&rq
->lock
);
878 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
879 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
884 return task_current(rq
, p
);
888 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
892 * We can optimise this out completely for !SMP, because the
893 * SMP rebalancing from interrupt is the only thing that cares
898 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
899 raw_spin_unlock_irq(&rq
->lock
);
901 raw_spin_unlock(&rq
->lock
);
905 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
909 * After ->oncpu is cleared, the task can be moved to a different CPU.
910 * We must ensure this doesn't happen until the switch is completely
916 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
920 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
923 * Check whether the task is waking, we use this to synchronize ->cpus_allowed
926 static inline int task_is_waking(struct task_struct
*p
)
928 return unlikely(p
->state
== TASK_WAKING
);
932 * __task_rq_lock - lock the runqueue a given task resides on.
933 * Must be called interrupts disabled.
935 static inline struct rq
*__task_rq_lock(struct task_struct
*p
)
942 raw_spin_lock(&rq
->lock
);
943 if (likely(rq
== task_rq(p
)))
945 raw_spin_unlock(&rq
->lock
);
950 * task_rq_lock - lock the runqueue a given task resides on and disable
951 * interrupts. Note the ordering: we can safely lookup the task_rq without
952 * explicitly disabling preemption.
954 static struct rq
*task_rq_lock(struct task_struct
*p
, unsigned long *flags
)
960 local_irq_save(*flags
);
962 raw_spin_lock(&rq
->lock
);
963 if (likely(rq
== task_rq(p
)))
965 raw_spin_unlock_irqrestore(&rq
->lock
, *flags
);
969 static void __task_rq_unlock(struct rq
*rq
)
972 raw_spin_unlock(&rq
->lock
);
975 static inline void task_rq_unlock(struct rq
*rq
, unsigned long *flags
)
978 raw_spin_unlock_irqrestore(&rq
->lock
, *flags
);
982 * this_rq_lock - lock this runqueue and disable interrupts.
984 static struct rq
*this_rq_lock(void)
991 raw_spin_lock(&rq
->lock
);
996 #ifdef CONFIG_SCHED_HRTICK
998 * Use HR-timers to deliver accurate preemption points.
1000 * Its all a bit involved since we cannot program an hrt while holding the
1001 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
1004 * When we get rescheduled we reprogram the hrtick_timer outside of the
1010 * - enabled by features
1011 * - hrtimer is actually high res
1013 static inline int hrtick_enabled(struct rq
*rq
)
1015 if (!sched_feat(HRTICK
))
1017 if (!cpu_active(cpu_of(rq
)))
1019 return hrtimer_is_hres_active(&rq
->hrtick_timer
);
1022 static void hrtick_clear(struct rq
*rq
)
1024 if (hrtimer_active(&rq
->hrtick_timer
))
1025 hrtimer_cancel(&rq
->hrtick_timer
);
1029 * High-resolution timer tick.
1030 * Runs from hardirq context with interrupts disabled.
1032 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
1034 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
1036 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1038 raw_spin_lock(&rq
->lock
);
1039 update_rq_clock(rq
);
1040 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
1041 raw_spin_unlock(&rq
->lock
);
1043 return HRTIMER_NORESTART
;
1048 * called from hardirq (IPI) context
1050 static void __hrtick_start(void *arg
)
1052 struct rq
*rq
= arg
;
1054 raw_spin_lock(&rq
->lock
);
1055 hrtimer_restart(&rq
->hrtick_timer
);
1056 rq
->hrtick_csd_pending
= 0;
1057 raw_spin_unlock(&rq
->lock
);
1061 * Called to set the hrtick timer state.
1063 * called with rq->lock held and irqs disabled
1065 static void hrtick_start(struct rq
*rq
, u64 delay
)
1067 struct hrtimer
*timer
= &rq
->hrtick_timer
;
1068 ktime_t time
= ktime_add_ns(timer
->base
->get_time(), delay
);
1070 hrtimer_set_expires(timer
, time
);
1072 if (rq
== this_rq()) {
1073 hrtimer_restart(timer
);
1074 } else if (!rq
->hrtick_csd_pending
) {
1075 __smp_call_function_single(cpu_of(rq
), &rq
->hrtick_csd
, 0);
1076 rq
->hrtick_csd_pending
= 1;
1081 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
1083 int cpu
= (int)(long)hcpu
;
1086 case CPU_UP_CANCELED
:
1087 case CPU_UP_CANCELED_FROZEN
:
1088 case CPU_DOWN_PREPARE
:
1089 case CPU_DOWN_PREPARE_FROZEN
:
1091 case CPU_DEAD_FROZEN
:
1092 hrtick_clear(cpu_rq(cpu
));
1099 static __init
void init_hrtick(void)
1101 hotcpu_notifier(hotplug_hrtick
, 0);
1105 * Called to set the hrtick timer state.
1107 * called with rq->lock held and irqs disabled
1109 static void hrtick_start(struct rq
*rq
, u64 delay
)
1111 __hrtimer_start_range_ns(&rq
->hrtick_timer
, ns_to_ktime(delay
), 0,
1112 HRTIMER_MODE_REL_PINNED
, 0);
1115 static inline void init_hrtick(void)
1118 #endif /* CONFIG_SMP */
1120 static void init_rq_hrtick(struct rq
*rq
)
1123 rq
->hrtick_csd_pending
= 0;
1125 rq
->hrtick_csd
.flags
= 0;
1126 rq
->hrtick_csd
.func
= __hrtick_start
;
1127 rq
->hrtick_csd
.info
= rq
;
1130 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1131 rq
->hrtick_timer
.function
= hrtick
;
1133 #else /* CONFIG_SCHED_HRTICK */
1134 static inline void hrtick_clear(struct rq
*rq
)
1138 static inline void init_rq_hrtick(struct rq
*rq
)
1142 static inline void init_hrtick(void)
1145 #endif /* CONFIG_SCHED_HRTICK */
1148 * resched_task - mark a task 'to be rescheduled now'.
1150 * On UP this means the setting of the need_resched flag, on SMP it
1151 * might also involve a cross-CPU call to trigger the scheduler on
1156 #ifndef tsk_is_polling
1157 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1160 static void resched_task(struct task_struct
*p
)
1164 assert_raw_spin_locked(&task_rq(p
)->lock
);
1166 if (test_tsk_need_resched(p
))
1169 set_tsk_need_resched(p
);
1172 if (cpu
== smp_processor_id())
1175 /* NEED_RESCHED must be visible before we test polling */
1177 if (!tsk_is_polling(p
))
1178 smp_send_reschedule(cpu
);
1181 static void resched_cpu(int cpu
)
1183 struct rq
*rq
= cpu_rq(cpu
);
1184 unsigned long flags
;
1186 if (!raw_spin_trylock_irqsave(&rq
->lock
, flags
))
1188 resched_task(cpu_curr(cpu
));
1189 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
1194 * In the semi idle case, use the nearest busy cpu for migrating timers
1195 * from an idle cpu. This is good for power-savings.
1197 * We don't do similar optimization for completely idle system, as
1198 * selecting an idle cpu will add more delays to the timers than intended
1199 * (as that cpu's timer base may not be uptodate wrt jiffies etc).
1201 int get_nohz_timer_target(void)
1203 int cpu
= smp_processor_id();
1205 struct sched_domain
*sd
;
1207 for_each_domain(cpu
, sd
) {
1208 for_each_cpu(i
, sched_domain_span(sd
))
1215 * When add_timer_on() enqueues a timer into the timer wheel of an
1216 * idle CPU then this timer might expire before the next timer event
1217 * which is scheduled to wake up that CPU. In case of a completely
1218 * idle system the next event might even be infinite time into the
1219 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1220 * leaves the inner idle loop so the newly added timer is taken into
1221 * account when the CPU goes back to idle and evaluates the timer
1222 * wheel for the next timer event.
1224 void wake_up_idle_cpu(int cpu
)
1226 struct rq
*rq
= cpu_rq(cpu
);
1228 if (cpu
== smp_processor_id())
1232 * This is safe, as this function is called with the timer
1233 * wheel base lock of (cpu) held. When the CPU is on the way
1234 * to idle and has not yet set rq->curr to idle then it will
1235 * be serialized on the timer wheel base lock and take the new
1236 * timer into account automatically.
1238 if (rq
->curr
!= rq
->idle
)
1242 * We can set TIF_RESCHED on the idle task of the other CPU
1243 * lockless. The worst case is that the other CPU runs the
1244 * idle task through an additional NOOP schedule()
1246 set_tsk_need_resched(rq
->idle
);
1248 /* NEED_RESCHED must be visible before we test polling */
1250 if (!tsk_is_polling(rq
->idle
))
1251 smp_send_reschedule(cpu
);
1254 #endif /* CONFIG_NO_HZ */
1256 static u64
sched_avg_period(void)
1258 return (u64
)sysctl_sched_time_avg
* NSEC_PER_MSEC
/ 2;
1261 static void sched_avg_update(struct rq
*rq
)
1263 s64 period
= sched_avg_period();
1265 while ((s64
)(rq
->clock
- rq
->age_stamp
) > period
) {
1267 * Inline assembly required to prevent the compiler
1268 * optimising this loop into a divmod call.
1269 * See __iter_div_u64_rem() for another example of this.
1271 asm("" : "+rm" (rq
->age_stamp
));
1272 rq
->age_stamp
+= period
;
1277 static void sched_rt_avg_update(struct rq
*rq
, u64 rt_delta
)
1279 rq
->rt_avg
+= rt_delta
;
1280 sched_avg_update(rq
);
1283 #else /* !CONFIG_SMP */
1284 static void resched_task(struct task_struct
*p
)
1286 assert_raw_spin_locked(&task_rq(p
)->lock
);
1287 set_tsk_need_resched(p
);
1290 static void sched_rt_avg_update(struct rq
*rq
, u64 rt_delta
)
1294 static void sched_avg_update(struct rq
*rq
)
1297 #endif /* CONFIG_SMP */
1299 #if BITS_PER_LONG == 32
1300 # define WMULT_CONST (~0UL)
1302 # define WMULT_CONST (1UL << 32)
1305 #define WMULT_SHIFT 32
1308 * Shift right and round:
1310 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1313 * delta *= weight / lw
1315 static unsigned long
1316 calc_delta_mine(unsigned long delta_exec
, unsigned long weight
,
1317 struct load_weight
*lw
)
1321 if (!lw
->inv_weight
) {
1322 if (BITS_PER_LONG
> 32 && unlikely(lw
->weight
>= WMULT_CONST
))
1325 lw
->inv_weight
= 1 + (WMULT_CONST
-lw
->weight
/2)
1329 tmp
= (u64
)delta_exec
* weight
;
1331 * Check whether we'd overflow the 64-bit multiplication:
1333 if (unlikely(tmp
> WMULT_CONST
))
1334 tmp
= SRR(SRR(tmp
, WMULT_SHIFT
/2) * lw
->inv_weight
,
1337 tmp
= SRR(tmp
* lw
->inv_weight
, WMULT_SHIFT
);
1339 return (unsigned long)min(tmp
, (u64
)(unsigned long)LONG_MAX
);
1342 static inline void update_load_add(struct load_weight
*lw
, unsigned long inc
)
1348 static inline void update_load_sub(struct load_weight
*lw
, unsigned long dec
)
1354 static inline void update_load_set(struct load_weight
*lw
, unsigned long w
)
1361 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1362 * of tasks with abnormal "nice" values across CPUs the contribution that
1363 * each task makes to its run queue's load is weighted according to its
1364 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1365 * scaled version of the new time slice allocation that they receive on time
1369 #define WEIGHT_IDLEPRIO 3
1370 #define WMULT_IDLEPRIO 1431655765
1373 * Nice levels are multiplicative, with a gentle 10% change for every
1374 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1375 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1376 * that remained on nice 0.
1378 * The "10% effect" is relative and cumulative: from _any_ nice level,
1379 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1380 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1381 * If a task goes up by ~10% and another task goes down by ~10% then
1382 * the relative distance between them is ~25%.)
1384 static const int prio_to_weight
[40] = {
1385 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1386 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1387 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1388 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1389 /* 0 */ 1024, 820, 655, 526, 423,
1390 /* 5 */ 335, 272, 215, 172, 137,
1391 /* 10 */ 110, 87, 70, 56, 45,
1392 /* 15 */ 36, 29, 23, 18, 15,
1396 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1398 * In cases where the weight does not change often, we can use the
1399 * precalculated inverse to speed up arithmetics by turning divisions
1400 * into multiplications:
1402 static const u32 prio_to_wmult
[40] = {
1403 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1404 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1405 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1406 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1407 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1408 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1409 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1410 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1413 /* Time spent by the tasks of the cpu accounting group executing in ... */
1414 enum cpuacct_stat_index
{
1415 CPUACCT_STAT_USER
, /* ... user mode */
1416 CPUACCT_STAT_SYSTEM
, /* ... kernel mode */
1418 CPUACCT_STAT_NSTATS
,
1421 #ifdef CONFIG_CGROUP_CPUACCT
1422 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
);
1423 static void cpuacct_update_stats(struct task_struct
*tsk
,
1424 enum cpuacct_stat_index idx
, cputime_t val
);
1426 static inline void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
) {}
1427 static inline void cpuacct_update_stats(struct task_struct
*tsk
,
1428 enum cpuacct_stat_index idx
, cputime_t val
) {}
1431 static inline void inc_cpu_load(struct rq
*rq
, unsigned long load
)
1433 update_load_add(&rq
->load
, load
);
1436 static inline void dec_cpu_load(struct rq
*rq
, unsigned long load
)
1438 update_load_sub(&rq
->load
, load
);
1441 #if (defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)) || defined(CONFIG_RT_GROUP_SCHED)
1442 typedef int (*tg_visitor
)(struct task_group
*, void *);
1445 * Iterate the full tree, calling @down when first entering a node and @up when
1446 * leaving it for the final time.
1448 static int walk_tg_tree(tg_visitor down
, tg_visitor up
, void *data
)
1450 struct task_group
*parent
, *child
;
1454 parent
= &root_task_group
;
1456 ret
= (*down
)(parent
, data
);
1459 list_for_each_entry_rcu(child
, &parent
->children
, siblings
) {
1466 ret
= (*up
)(parent
, data
);
1471 parent
= parent
->parent
;
1480 static int tg_nop(struct task_group
*tg
, void *data
)
1487 /* Used instead of source_load when we know the type == 0 */
1488 static unsigned long weighted_cpuload(const int cpu
)
1490 return cpu_rq(cpu
)->load
.weight
;
1494 * Return a low guess at the load of a migration-source cpu weighted
1495 * according to the scheduling class and "nice" value.
1497 * We want to under-estimate the load of migration sources, to
1498 * balance conservatively.
1500 static unsigned long source_load(int cpu
, int type
)
1502 struct rq
*rq
= cpu_rq(cpu
);
1503 unsigned long total
= weighted_cpuload(cpu
);
1505 if (type
== 0 || !sched_feat(LB_BIAS
))
1508 return min(rq
->cpu_load
[type
-1], total
);
1512 * Return a high guess at the load of a migration-target cpu weighted
1513 * according to the scheduling class and "nice" value.
1515 static unsigned long target_load(int cpu
, int type
)
1517 struct rq
*rq
= cpu_rq(cpu
);
1518 unsigned long total
= weighted_cpuload(cpu
);
1520 if (type
== 0 || !sched_feat(LB_BIAS
))
1523 return max(rq
->cpu_load
[type
-1], total
);
1526 static unsigned long power_of(int cpu
)
1528 return cpu_rq(cpu
)->cpu_power
;
1531 static int task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
);
1533 static unsigned long cpu_avg_load_per_task(int cpu
)
1535 struct rq
*rq
= cpu_rq(cpu
);
1536 unsigned long nr_running
= ACCESS_ONCE(rq
->nr_running
);
1539 rq
->avg_load_per_task
= rq
->load
.weight
/ nr_running
;
1541 rq
->avg_load_per_task
= 0;
1543 return rq
->avg_load_per_task
;
1546 #ifdef CONFIG_FAIR_GROUP_SCHED
1549 * Compute the cpu's hierarchical load factor for each task group.
1550 * This needs to be done in a top-down fashion because the load of a child
1551 * group is a fraction of its parents load.
1553 static int tg_load_down(struct task_group
*tg
, void *data
)
1556 long cpu
= (long)data
;
1559 load
= cpu_rq(cpu
)->load
.weight
;
1561 load
= tg
->parent
->cfs_rq
[cpu
]->h_load
;
1562 load
*= tg
->se
[cpu
]->load
.weight
;
1563 load
/= tg
->parent
->cfs_rq
[cpu
]->load
.weight
+ 1;
1566 tg
->cfs_rq
[cpu
]->h_load
= load
;
1571 static void update_h_load(long cpu
)
1573 walk_tg_tree(tg_load_down
, tg_nop
, (void *)cpu
);
1578 #ifdef CONFIG_PREEMPT
1580 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
);
1583 * fair double_lock_balance: Safely acquires both rq->locks in a fair
1584 * way at the expense of forcing extra atomic operations in all
1585 * invocations. This assures that the double_lock is acquired using the
1586 * same underlying policy as the spinlock_t on this architecture, which
1587 * reduces latency compared to the unfair variant below. However, it
1588 * also adds more overhead and therefore may reduce throughput.
1590 static inline int _double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1591 __releases(this_rq
->lock
)
1592 __acquires(busiest
->lock
)
1593 __acquires(this_rq
->lock
)
1595 raw_spin_unlock(&this_rq
->lock
);
1596 double_rq_lock(this_rq
, busiest
);
1603 * Unfair double_lock_balance: Optimizes throughput at the expense of
1604 * latency by eliminating extra atomic operations when the locks are
1605 * already in proper order on entry. This favors lower cpu-ids and will
1606 * grant the double lock to lower cpus over higher ids under contention,
1607 * regardless of entry order into the function.
1609 static int _double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1610 __releases(this_rq
->lock
)
1611 __acquires(busiest
->lock
)
1612 __acquires(this_rq
->lock
)
1616 if (unlikely(!raw_spin_trylock(&busiest
->lock
))) {
1617 if (busiest
< this_rq
) {
1618 raw_spin_unlock(&this_rq
->lock
);
1619 raw_spin_lock(&busiest
->lock
);
1620 raw_spin_lock_nested(&this_rq
->lock
,
1621 SINGLE_DEPTH_NESTING
);
1624 raw_spin_lock_nested(&busiest
->lock
,
1625 SINGLE_DEPTH_NESTING
);
1630 #endif /* CONFIG_PREEMPT */
1633 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
1635 static int double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1637 if (unlikely(!irqs_disabled())) {
1638 /* printk() doesn't work good under rq->lock */
1639 raw_spin_unlock(&this_rq
->lock
);
1643 return _double_lock_balance(this_rq
, busiest
);
1646 static inline void double_unlock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1647 __releases(busiest
->lock
)
1649 raw_spin_unlock(&busiest
->lock
);
1650 lock_set_subclass(&this_rq
->lock
.dep_map
, 0, _RET_IP_
);
1654 * double_rq_lock - safely lock two runqueues
1656 * Note this does not disable interrupts like task_rq_lock,
1657 * you need to do so manually before calling.
1659 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
)
1660 __acquires(rq1
->lock
)
1661 __acquires(rq2
->lock
)
1663 BUG_ON(!irqs_disabled());
1665 raw_spin_lock(&rq1
->lock
);
1666 __acquire(rq2
->lock
); /* Fake it out ;) */
1669 raw_spin_lock(&rq1
->lock
);
1670 raw_spin_lock_nested(&rq2
->lock
, SINGLE_DEPTH_NESTING
);
1672 raw_spin_lock(&rq2
->lock
);
1673 raw_spin_lock_nested(&rq1
->lock
, SINGLE_DEPTH_NESTING
);
1679 * double_rq_unlock - safely unlock two runqueues
1681 * Note this does not restore interrupts like task_rq_unlock,
1682 * you need to do so manually after calling.
1684 static void double_rq_unlock(struct rq
*rq1
, struct rq
*rq2
)
1685 __releases(rq1
->lock
)
1686 __releases(rq2
->lock
)
1688 raw_spin_unlock(&rq1
->lock
);
1690 raw_spin_unlock(&rq2
->lock
);
1692 __release(rq2
->lock
);
1697 static void calc_load_account_idle(struct rq
*this_rq
);
1698 static void update_sysctl(void);
1699 static int get_update_sysctl_factor(void);
1700 static void update_cpu_load(struct rq
*this_rq
);
1702 static inline void __set_task_cpu(struct task_struct
*p
, unsigned int cpu
)
1704 set_task_rq(p
, cpu
);
1707 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1708 * successfuly executed on another CPU. We must ensure that updates of
1709 * per-task data have been completed by this moment.
1712 task_thread_info(p
)->cpu
= cpu
;
1716 static const struct sched_class rt_sched_class
;
1718 #define sched_class_highest (&stop_sched_class)
1719 #define for_each_class(class) \
1720 for (class = sched_class_highest; class; class = class->next)
1722 #include "sched_stats.h"
1724 static void inc_nr_running(struct rq
*rq
)
1729 static void dec_nr_running(struct rq
*rq
)
1734 static void set_load_weight(struct task_struct
*p
)
1737 * SCHED_IDLE tasks get minimal weight:
1739 if (p
->policy
== SCHED_IDLE
) {
1740 p
->se
.load
.weight
= WEIGHT_IDLEPRIO
;
1741 p
->se
.load
.inv_weight
= WMULT_IDLEPRIO
;
1745 p
->se
.load
.weight
= prio_to_weight
[p
->static_prio
- MAX_RT_PRIO
];
1746 p
->se
.load
.inv_weight
= prio_to_wmult
[p
->static_prio
- MAX_RT_PRIO
];
1749 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
1751 update_rq_clock(rq
);
1752 sched_info_queued(p
);
1753 p
->sched_class
->enqueue_task(rq
, p
, flags
);
1757 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
1759 update_rq_clock(rq
);
1760 sched_info_dequeued(p
);
1761 p
->sched_class
->dequeue_task(rq
, p
, flags
);
1766 * activate_task - move a task to the runqueue.
1768 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
1770 if (task_contributes_to_load(p
))
1771 rq
->nr_uninterruptible
--;
1773 enqueue_task(rq
, p
, flags
);
1778 * deactivate_task - remove a task from the runqueue.
1780 static void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
1782 if (task_contributes_to_load(p
))
1783 rq
->nr_uninterruptible
++;
1785 dequeue_task(rq
, p
, flags
);
1789 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
1792 * There are no locks covering percpu hardirq/softirq time.
1793 * They are only modified in account_system_vtime, on corresponding CPU
1794 * with interrupts disabled. So, writes are safe.
1795 * They are read and saved off onto struct rq in update_rq_clock().
1796 * This may result in other CPU reading this CPU's irq time and can
1797 * race with irq/account_system_vtime on this CPU. We would either get old
1798 * or new value (or semi updated value on 32 bit) with a side effect of
1799 * accounting a slice of irq time to wrong task when irq is in progress
1800 * while we read rq->clock. That is a worthy compromise in place of having
1801 * locks on each irq in account_system_time.
1803 static DEFINE_PER_CPU(u64
, cpu_hardirq_time
);
1804 static DEFINE_PER_CPU(u64
, cpu_softirq_time
);
1806 static DEFINE_PER_CPU(u64
, irq_start_time
);
1807 static int sched_clock_irqtime
;
1809 void enable_sched_clock_irqtime(void)
1811 sched_clock_irqtime
= 1;
1814 void disable_sched_clock_irqtime(void)
1816 sched_clock_irqtime
= 0;
1819 static u64
irq_time_cpu(int cpu
)
1821 if (!sched_clock_irqtime
)
1824 return per_cpu(cpu_softirq_time
, cpu
) + per_cpu(cpu_hardirq_time
, cpu
);
1827 void account_system_vtime(struct task_struct
*curr
)
1829 unsigned long flags
;
1833 if (!sched_clock_irqtime
)
1836 local_irq_save(flags
);
1838 cpu
= smp_processor_id();
1839 now
= sched_clock_cpu(cpu
);
1840 delta
= now
- per_cpu(irq_start_time
, cpu
);
1841 per_cpu(irq_start_time
, cpu
) = now
;
1843 * We do not account for softirq time from ksoftirqd here.
1844 * We want to continue accounting softirq time to ksoftirqd thread
1845 * in that case, so as not to confuse scheduler with a special task
1846 * that do not consume any time, but still wants to run.
1848 if (hardirq_count())
1849 per_cpu(cpu_hardirq_time
, cpu
) += delta
;
1850 else if (in_serving_softirq() && !(curr
->flags
& PF_KSOFTIRQD
))
1851 per_cpu(cpu_softirq_time
, cpu
) += delta
;
1853 local_irq_restore(flags
);
1855 EXPORT_SYMBOL_GPL(account_system_vtime
);
1857 static void sched_irq_time_avg_update(struct rq
*rq
, u64 curr_irq_time
)
1859 if (sched_clock_irqtime
&& sched_feat(NONIRQ_POWER
)) {
1860 u64 delta_irq
= curr_irq_time
- rq
->prev_irq_time
;
1861 rq
->prev_irq_time
= curr_irq_time
;
1862 sched_rt_avg_update(rq
, delta_irq
);
1868 static u64
irq_time_cpu(int cpu
)
1873 static void sched_irq_time_avg_update(struct rq
*rq
, u64 curr_irq_time
) { }
1877 #include "sched_idletask.c"
1878 #include "sched_fair.c"
1879 #include "sched_rt.c"
1880 #include "sched_autogroup.c"
1881 #include "sched_stoptask.c"
1882 #ifdef CONFIG_SCHED_DEBUG
1883 # include "sched_debug.c"
1886 void sched_set_stop_task(int cpu
, struct task_struct
*stop
)
1888 struct sched_param param
= { .sched_priority
= MAX_RT_PRIO
- 1 };
1889 struct task_struct
*old_stop
= cpu_rq(cpu
)->stop
;
1893 * Make it appear like a SCHED_FIFO task, its something
1894 * userspace knows about and won't get confused about.
1896 * Also, it will make PI more or less work without too
1897 * much confusion -- but then, stop work should not
1898 * rely on PI working anyway.
1900 sched_setscheduler_nocheck(stop
, SCHED_FIFO
, ¶m
);
1902 stop
->sched_class
= &stop_sched_class
;
1905 cpu_rq(cpu
)->stop
= stop
;
1909 * Reset it back to a normal scheduling class so that
1910 * it can die in pieces.
1912 old_stop
->sched_class
= &rt_sched_class
;
1917 * __normal_prio - return the priority that is based on the static prio
1919 static inline int __normal_prio(struct task_struct
*p
)
1921 return p
->static_prio
;
1925 * Calculate the expected normal priority: i.e. priority
1926 * without taking RT-inheritance into account. Might be
1927 * boosted by interactivity modifiers. Changes upon fork,
1928 * setprio syscalls, and whenever the interactivity
1929 * estimator recalculates.
1931 static inline int normal_prio(struct task_struct
*p
)
1935 if (task_has_rt_policy(p
))
1936 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
1938 prio
= __normal_prio(p
);
1943 * Calculate the current priority, i.e. the priority
1944 * taken into account by the scheduler. This value might
1945 * be boosted by RT tasks, or might be boosted by
1946 * interactivity modifiers. Will be RT if the task got
1947 * RT-boosted. If not then it returns p->normal_prio.
1949 static int effective_prio(struct task_struct
*p
)
1951 p
->normal_prio
= normal_prio(p
);
1953 * If we are RT tasks or we were boosted to RT priority,
1954 * keep the priority unchanged. Otherwise, update priority
1955 * to the normal priority:
1957 if (!rt_prio(p
->prio
))
1958 return p
->normal_prio
;
1963 * task_curr - is this task currently executing on a CPU?
1964 * @p: the task in question.
1966 inline int task_curr(const struct task_struct
*p
)
1968 return cpu_curr(task_cpu(p
)) == p
;
1971 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
1972 const struct sched_class
*prev_class
,
1973 int oldprio
, int running
)
1975 if (prev_class
!= p
->sched_class
) {
1976 if (prev_class
->switched_from
)
1977 prev_class
->switched_from(rq
, p
, running
);
1978 p
->sched_class
->switched_to(rq
, p
, running
);
1980 p
->sched_class
->prio_changed(rq
, p
, oldprio
, running
);
1983 static void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int flags
)
1985 const struct sched_class
*class;
1987 if (p
->sched_class
== rq
->curr
->sched_class
) {
1988 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
, flags
);
1990 for_each_class(class) {
1991 if (class == rq
->curr
->sched_class
)
1993 if (class == p
->sched_class
) {
1994 resched_task(rq
->curr
);
2001 * A queue event has occurred, and we're going to schedule. In
2002 * this case, we can save a useless back to back clock update.
2004 if (test_tsk_need_resched(rq
->curr
))
2005 rq
->skip_clock_update
= 1;
2010 * Is this task likely cache-hot:
2013 task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
)
2017 if (p
->sched_class
!= &fair_sched_class
)
2020 if (unlikely(p
->policy
== SCHED_IDLE
))
2024 * Buddy candidates are cache hot:
2026 if (sched_feat(CACHE_HOT_BUDDY
) && this_rq()->nr_running
&&
2027 (&p
->se
== cfs_rq_of(&p
->se
)->next
||
2028 &p
->se
== cfs_rq_of(&p
->se
)->last
))
2031 if (sysctl_sched_migration_cost
== -1)
2033 if (sysctl_sched_migration_cost
== 0)
2036 delta
= now
- p
->se
.exec_start
;
2038 return delta
< (s64
)sysctl_sched_migration_cost
;
2041 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
2043 #ifdef CONFIG_SCHED_DEBUG
2045 * We should never call set_task_cpu() on a blocked task,
2046 * ttwu() will sort out the placement.
2048 WARN_ON_ONCE(p
->state
!= TASK_RUNNING
&& p
->state
!= TASK_WAKING
&&
2049 !(task_thread_info(p
)->preempt_count
& PREEMPT_ACTIVE
));
2052 trace_sched_migrate_task(p
, new_cpu
);
2054 if (task_cpu(p
) != new_cpu
) {
2055 p
->se
.nr_migrations
++;
2056 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS
, 1, 1, NULL
, 0);
2059 __set_task_cpu(p
, new_cpu
);
2062 struct migration_arg
{
2063 struct task_struct
*task
;
2067 static int migration_cpu_stop(void *data
);
2070 * The task's runqueue lock must be held.
2071 * Returns true if you have to wait for migration thread.
2073 static bool migrate_task(struct task_struct
*p
, struct rq
*rq
)
2076 * If the task is not on a runqueue (and not running), then
2077 * the next wake-up will properly place the task.
2079 return p
->se
.on_rq
|| task_running(rq
, p
);
2083 * wait_task_inactive - wait for a thread to unschedule.
2085 * If @match_state is nonzero, it's the @p->state value just checked and
2086 * not expected to change. If it changes, i.e. @p might have woken up,
2087 * then return zero. When we succeed in waiting for @p to be off its CPU,
2088 * we return a positive number (its total switch count). If a second call
2089 * a short while later returns the same number, the caller can be sure that
2090 * @p has remained unscheduled the whole time.
2092 * The caller must ensure that the task *will* unschedule sometime soon,
2093 * else this function might spin for a *long* time. This function can't
2094 * be called with interrupts off, or it may introduce deadlock with
2095 * smp_call_function() if an IPI is sent by the same process we are
2096 * waiting to become inactive.
2098 unsigned long wait_task_inactive(struct task_struct
*p
, long match_state
)
2100 unsigned long flags
;
2107 * We do the initial early heuristics without holding
2108 * any task-queue locks at all. We'll only try to get
2109 * the runqueue lock when things look like they will
2115 * If the task is actively running on another CPU
2116 * still, just relax and busy-wait without holding
2119 * NOTE! Since we don't hold any locks, it's not
2120 * even sure that "rq" stays as the right runqueue!
2121 * But we don't care, since "task_running()" will
2122 * return false if the runqueue has changed and p
2123 * is actually now running somewhere else!
2125 while (task_running(rq
, p
)) {
2126 if (match_state
&& unlikely(p
->state
!= match_state
))
2132 * Ok, time to look more closely! We need the rq
2133 * lock now, to be *sure*. If we're wrong, we'll
2134 * just go back and repeat.
2136 rq
= task_rq_lock(p
, &flags
);
2137 trace_sched_wait_task(p
);
2138 running
= task_running(rq
, p
);
2139 on_rq
= p
->se
.on_rq
;
2141 if (!match_state
|| p
->state
== match_state
)
2142 ncsw
= p
->nvcsw
| LONG_MIN
; /* sets MSB */
2143 task_rq_unlock(rq
, &flags
);
2146 * If it changed from the expected state, bail out now.
2148 if (unlikely(!ncsw
))
2152 * Was it really running after all now that we
2153 * checked with the proper locks actually held?
2155 * Oops. Go back and try again..
2157 if (unlikely(running
)) {
2163 * It's not enough that it's not actively running,
2164 * it must be off the runqueue _entirely_, and not
2167 * So if it was still runnable (but just not actively
2168 * running right now), it's preempted, and we should
2169 * yield - it could be a while.
2171 if (unlikely(on_rq
)) {
2172 schedule_timeout_uninterruptible(1);
2177 * Ahh, all good. It wasn't running, and it wasn't
2178 * runnable, which means that it will never become
2179 * running in the future either. We're all done!
2188 * kick_process - kick a running thread to enter/exit the kernel
2189 * @p: the to-be-kicked thread
2191 * Cause a process which is running on another CPU to enter
2192 * kernel-mode, without any delay. (to get signals handled.)
2194 * NOTE: this function doesnt have to take the runqueue lock,
2195 * because all it wants to ensure is that the remote task enters
2196 * the kernel. If the IPI races and the task has been migrated
2197 * to another CPU then no harm is done and the purpose has been
2200 void kick_process(struct task_struct
*p
)
2206 if ((cpu
!= smp_processor_id()) && task_curr(p
))
2207 smp_send_reschedule(cpu
);
2210 EXPORT_SYMBOL_GPL(kick_process
);
2211 #endif /* CONFIG_SMP */
2214 * task_oncpu_function_call - call a function on the cpu on which a task runs
2215 * @p: the task to evaluate
2216 * @func: the function to be called
2217 * @info: the function call argument
2219 * Calls the function @func when the task is currently running. This might
2220 * be on the current CPU, which just calls the function directly
2222 void task_oncpu_function_call(struct task_struct
*p
,
2223 void (*func
) (void *info
), void *info
)
2230 smp_call_function_single(cpu
, func
, info
, 1);
2236 * ->cpus_allowed is protected by either TASK_WAKING or rq->lock held.
2238 static int select_fallback_rq(int cpu
, struct task_struct
*p
)
2241 const struct cpumask
*nodemask
= cpumask_of_node(cpu_to_node(cpu
));
2243 /* Look for allowed, online CPU in same node. */
2244 for_each_cpu_and(dest_cpu
, nodemask
, cpu_active_mask
)
2245 if (cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
2248 /* Any allowed, online CPU? */
2249 dest_cpu
= cpumask_any_and(&p
->cpus_allowed
, cpu_active_mask
);
2250 if (dest_cpu
< nr_cpu_ids
)
2253 /* No more Mr. Nice Guy. */
2254 dest_cpu
= cpuset_cpus_allowed_fallback(p
);
2256 * Don't tell them about moving exiting tasks or
2257 * kernel threads (both mm NULL), since they never
2260 if (p
->mm
&& printk_ratelimit()) {
2261 printk(KERN_INFO
"process %d (%s) no longer affine to cpu%d\n",
2262 task_pid_nr(p
), p
->comm
, cpu
);
2269 * The caller (fork, wakeup) owns TASK_WAKING, ->cpus_allowed is stable.
2272 int select_task_rq(struct rq
*rq
, struct task_struct
*p
, int sd_flags
, int wake_flags
)
2274 int cpu
= p
->sched_class
->select_task_rq(rq
, p
, sd_flags
, wake_flags
);
2277 * In order not to call set_task_cpu() on a blocking task we need
2278 * to rely on ttwu() to place the task on a valid ->cpus_allowed
2281 * Since this is common to all placement strategies, this lives here.
2283 * [ this allows ->select_task() to simply return task_cpu(p) and
2284 * not worry about this generic constraint ]
2286 if (unlikely(!cpumask_test_cpu(cpu
, &p
->cpus_allowed
) ||
2288 cpu
= select_fallback_rq(task_cpu(p
), p
);
2293 static void update_avg(u64
*avg
, u64 sample
)
2295 s64 diff
= sample
- *avg
;
2300 static inline void ttwu_activate(struct task_struct
*p
, struct rq
*rq
,
2301 bool is_sync
, bool is_migrate
, bool is_local
,
2302 unsigned long en_flags
)
2304 schedstat_inc(p
, se
.statistics
.nr_wakeups
);
2306 schedstat_inc(p
, se
.statistics
.nr_wakeups_sync
);
2308 schedstat_inc(p
, se
.statistics
.nr_wakeups_migrate
);
2310 schedstat_inc(p
, se
.statistics
.nr_wakeups_local
);
2312 schedstat_inc(p
, se
.statistics
.nr_wakeups_remote
);
2314 activate_task(rq
, p
, en_flags
);
2317 static inline void ttwu_post_activation(struct task_struct
*p
, struct rq
*rq
,
2318 int wake_flags
, bool success
)
2320 trace_sched_wakeup(p
, success
);
2321 check_preempt_curr(rq
, p
, wake_flags
);
2323 p
->state
= TASK_RUNNING
;
2325 if (p
->sched_class
->task_woken
)
2326 p
->sched_class
->task_woken(rq
, p
);
2328 if (unlikely(rq
->idle_stamp
)) {
2329 u64 delta
= rq
->clock
- rq
->idle_stamp
;
2330 u64 max
= 2*sysctl_sched_migration_cost
;
2335 update_avg(&rq
->avg_idle
, delta
);
2339 /* if a worker is waking up, notify workqueue */
2340 if ((p
->flags
& PF_WQ_WORKER
) && success
)
2341 wq_worker_waking_up(p
, cpu_of(rq
));
2345 * try_to_wake_up - wake up a thread
2346 * @p: the thread to be awakened
2347 * @state: the mask of task states that can be woken
2348 * @wake_flags: wake modifier flags (WF_*)
2350 * Put it on the run-queue if it's not already there. The "current"
2351 * thread is always on the run-queue (except when the actual
2352 * re-schedule is in progress), and as such you're allowed to do
2353 * the simpler "current->state = TASK_RUNNING" to mark yourself
2354 * runnable without the overhead of this.
2356 * Returns %true if @p was woken up, %false if it was already running
2357 * or @state didn't match @p's state.
2359 static int try_to_wake_up(struct task_struct
*p
, unsigned int state
,
2362 int cpu
, orig_cpu
, this_cpu
, success
= 0;
2363 unsigned long flags
;
2364 unsigned long en_flags
= ENQUEUE_WAKEUP
;
2367 this_cpu
= get_cpu();
2370 rq
= task_rq_lock(p
, &flags
);
2371 if (!(p
->state
& state
))
2381 if (unlikely(task_running(rq
, p
)))
2385 * In order to handle concurrent wakeups and release the rq->lock
2386 * we put the task in TASK_WAKING state.
2388 * First fix up the nr_uninterruptible count:
2390 if (task_contributes_to_load(p
)) {
2391 if (likely(cpu_online(orig_cpu
)))
2392 rq
->nr_uninterruptible
--;
2394 this_rq()->nr_uninterruptible
--;
2396 p
->state
= TASK_WAKING
;
2398 if (p
->sched_class
->task_waking
) {
2399 p
->sched_class
->task_waking(rq
, p
);
2400 en_flags
|= ENQUEUE_WAKING
;
2403 cpu
= select_task_rq(rq
, p
, SD_BALANCE_WAKE
, wake_flags
);
2404 if (cpu
!= orig_cpu
)
2405 set_task_cpu(p
, cpu
);
2406 __task_rq_unlock(rq
);
2409 raw_spin_lock(&rq
->lock
);
2412 * We migrated the task without holding either rq->lock, however
2413 * since the task is not on the task list itself, nobody else
2414 * will try and migrate the task, hence the rq should match the
2415 * cpu we just moved it to.
2417 WARN_ON(task_cpu(p
) != cpu
);
2418 WARN_ON(p
->state
!= TASK_WAKING
);
2420 #ifdef CONFIG_SCHEDSTATS
2421 schedstat_inc(rq
, ttwu_count
);
2422 if (cpu
== this_cpu
)
2423 schedstat_inc(rq
, ttwu_local
);
2425 struct sched_domain
*sd
;
2426 for_each_domain(this_cpu
, sd
) {
2427 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
2428 schedstat_inc(sd
, ttwu_wake_remote
);
2433 #endif /* CONFIG_SCHEDSTATS */
2436 #endif /* CONFIG_SMP */
2437 ttwu_activate(p
, rq
, wake_flags
& WF_SYNC
, orig_cpu
!= cpu
,
2438 cpu
== this_cpu
, en_flags
);
2441 ttwu_post_activation(p
, rq
, wake_flags
, success
);
2443 task_rq_unlock(rq
, &flags
);
2450 * try_to_wake_up_local - try to wake up a local task with rq lock held
2451 * @p: the thread to be awakened
2453 * Put @p on the run-queue if it's not alredy there. The caller must
2454 * ensure that this_rq() is locked, @p is bound to this_rq() and not
2455 * the current task. this_rq() stays locked over invocation.
2457 static void try_to_wake_up_local(struct task_struct
*p
)
2459 struct rq
*rq
= task_rq(p
);
2460 bool success
= false;
2462 BUG_ON(rq
!= this_rq());
2463 BUG_ON(p
== current
);
2464 lockdep_assert_held(&rq
->lock
);
2466 if (!(p
->state
& TASK_NORMAL
))
2470 if (likely(!task_running(rq
, p
))) {
2471 schedstat_inc(rq
, ttwu_count
);
2472 schedstat_inc(rq
, ttwu_local
);
2474 ttwu_activate(p
, rq
, false, false, true, ENQUEUE_WAKEUP
);
2477 ttwu_post_activation(p
, rq
, 0, success
);
2481 * wake_up_process - Wake up a specific process
2482 * @p: The process to be woken up.
2484 * Attempt to wake up the nominated process and move it to the set of runnable
2485 * processes. Returns 1 if the process was woken up, 0 if it was already
2488 * It may be assumed that this function implies a write memory barrier before
2489 * changing the task state if and only if any tasks are woken up.
2491 int wake_up_process(struct task_struct
*p
)
2493 return try_to_wake_up(p
, TASK_ALL
, 0);
2495 EXPORT_SYMBOL(wake_up_process
);
2497 int wake_up_state(struct task_struct
*p
, unsigned int state
)
2499 return try_to_wake_up(p
, state
, 0);
2503 * Perform scheduler related setup for a newly forked process p.
2504 * p is forked by current.
2506 * __sched_fork() is basic setup used by init_idle() too:
2508 static void __sched_fork(struct task_struct
*p
)
2510 p
->se
.exec_start
= 0;
2511 p
->se
.sum_exec_runtime
= 0;
2512 p
->se
.prev_sum_exec_runtime
= 0;
2513 p
->se
.nr_migrations
= 0;
2515 #ifdef CONFIG_SCHEDSTATS
2516 memset(&p
->se
.statistics
, 0, sizeof(p
->se
.statistics
));
2519 INIT_LIST_HEAD(&p
->rt
.run_list
);
2521 INIT_LIST_HEAD(&p
->se
.group_node
);
2523 #ifdef CONFIG_PREEMPT_NOTIFIERS
2524 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
2529 * fork()/clone()-time setup:
2531 void sched_fork(struct task_struct
*p
, int clone_flags
)
2533 int cpu
= get_cpu();
2537 * We mark the process as running here. This guarantees that
2538 * nobody will actually run it, and a signal or other external
2539 * event cannot wake it up and insert it on the runqueue either.
2541 p
->state
= TASK_RUNNING
;
2544 * Revert to default priority/policy on fork if requested.
2546 if (unlikely(p
->sched_reset_on_fork
)) {
2547 if (p
->policy
== SCHED_FIFO
|| p
->policy
== SCHED_RR
) {
2548 p
->policy
= SCHED_NORMAL
;
2549 p
->normal_prio
= p
->static_prio
;
2552 if (PRIO_TO_NICE(p
->static_prio
) < 0) {
2553 p
->static_prio
= NICE_TO_PRIO(0);
2554 p
->normal_prio
= p
->static_prio
;
2559 * We don't need the reset flag anymore after the fork. It has
2560 * fulfilled its duty:
2562 p
->sched_reset_on_fork
= 0;
2566 * Make sure we do not leak PI boosting priority to the child.
2568 p
->prio
= current
->normal_prio
;
2570 if (!rt_prio(p
->prio
))
2571 p
->sched_class
= &fair_sched_class
;
2573 if (p
->sched_class
->task_fork
)
2574 p
->sched_class
->task_fork(p
);
2577 * The child is not yet in the pid-hash so no cgroup attach races,
2578 * and the cgroup is pinned to this child due to cgroup_fork()
2579 * is ran before sched_fork().
2581 * Silence PROVE_RCU.
2584 set_task_cpu(p
, cpu
);
2587 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2588 if (likely(sched_info_on()))
2589 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
2591 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
2594 #ifdef CONFIG_PREEMPT
2595 /* Want to start with kernel preemption disabled. */
2596 task_thread_info(p
)->preempt_count
= 1;
2598 plist_node_init(&p
->pushable_tasks
, MAX_PRIO
);
2604 * wake_up_new_task - wake up a newly created task for the first time.
2606 * This function will do some initial scheduler statistics housekeeping
2607 * that must be done for every newly created context, then puts the task
2608 * on the runqueue and wakes it.
2610 void wake_up_new_task(struct task_struct
*p
, unsigned long clone_flags
)
2612 unsigned long flags
;
2614 int cpu __maybe_unused
= get_cpu();
2617 rq
= task_rq_lock(p
, &flags
);
2618 p
->state
= TASK_WAKING
;
2621 * Fork balancing, do it here and not earlier because:
2622 * - cpus_allowed can change in the fork path
2623 * - any previously selected cpu might disappear through hotplug
2625 * We set TASK_WAKING so that select_task_rq() can drop rq->lock
2626 * without people poking at ->cpus_allowed.
2628 cpu
= select_task_rq(rq
, p
, SD_BALANCE_FORK
, 0);
2629 set_task_cpu(p
, cpu
);
2631 p
->state
= TASK_RUNNING
;
2632 task_rq_unlock(rq
, &flags
);
2635 rq
= task_rq_lock(p
, &flags
);
2636 activate_task(rq
, p
, 0);
2637 trace_sched_wakeup_new(p
, 1);
2638 check_preempt_curr(rq
, p
, WF_FORK
);
2640 if (p
->sched_class
->task_woken
)
2641 p
->sched_class
->task_woken(rq
, p
);
2643 task_rq_unlock(rq
, &flags
);
2647 #ifdef CONFIG_PREEMPT_NOTIFIERS
2650 * preempt_notifier_register - tell me when current is being preempted & rescheduled
2651 * @notifier: notifier struct to register
2653 void preempt_notifier_register(struct preempt_notifier
*notifier
)
2655 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
2657 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
2660 * preempt_notifier_unregister - no longer interested in preemption notifications
2661 * @notifier: notifier struct to unregister
2663 * This is safe to call from within a preemption notifier.
2665 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
2667 hlist_del(¬ifier
->link
);
2669 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
2671 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2673 struct preempt_notifier
*notifier
;
2674 struct hlist_node
*node
;
2676 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2677 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
2681 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2682 struct task_struct
*next
)
2684 struct preempt_notifier
*notifier
;
2685 struct hlist_node
*node
;
2687 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2688 notifier
->ops
->sched_out(notifier
, next
);
2691 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2693 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2698 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2699 struct task_struct
*next
)
2703 #endif /* CONFIG_PREEMPT_NOTIFIERS */
2706 * prepare_task_switch - prepare to switch tasks
2707 * @rq: the runqueue preparing to switch
2708 * @prev: the current task that is being switched out
2709 * @next: the task we are going to switch to.
2711 * This is called with the rq lock held and interrupts off. It must
2712 * be paired with a subsequent finish_task_switch after the context
2715 * prepare_task_switch sets up locking and calls architecture specific
2719 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
2720 struct task_struct
*next
)
2722 fire_sched_out_preempt_notifiers(prev
, next
);
2723 prepare_lock_switch(rq
, next
);
2724 prepare_arch_switch(next
);
2728 * finish_task_switch - clean up after a task-switch
2729 * @rq: runqueue associated with task-switch
2730 * @prev: the thread we just switched away from.
2732 * finish_task_switch must be called after the context switch, paired
2733 * with a prepare_task_switch call before the context switch.
2734 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2735 * and do any other architecture-specific cleanup actions.
2737 * Note that we may have delayed dropping an mm in context_switch(). If
2738 * so, we finish that here outside of the runqueue lock. (Doing it
2739 * with the lock held can cause deadlocks; see schedule() for
2742 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
2743 __releases(rq
->lock
)
2745 struct mm_struct
*mm
= rq
->prev_mm
;
2751 * A task struct has one reference for the use as "current".
2752 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2753 * schedule one last time. The schedule call will never return, and
2754 * the scheduled task must drop that reference.
2755 * The test for TASK_DEAD must occur while the runqueue locks are
2756 * still held, otherwise prev could be scheduled on another cpu, die
2757 * there before we look at prev->state, and then the reference would
2759 * Manfred Spraul <manfred@colorfullife.com>
2761 prev_state
= prev
->state
;
2762 finish_arch_switch(prev
);
2763 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
2764 local_irq_disable();
2765 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
2766 perf_event_task_sched_in(current
);
2767 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
2769 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
2770 finish_lock_switch(rq
, prev
);
2772 fire_sched_in_preempt_notifiers(current
);
2775 if (unlikely(prev_state
== TASK_DEAD
)) {
2777 * Remove function-return probe instances associated with this
2778 * task and put them back on the free list.
2780 kprobe_flush_task(prev
);
2781 put_task_struct(prev
);
2787 /* assumes rq->lock is held */
2788 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*prev
)
2790 if (prev
->sched_class
->pre_schedule
)
2791 prev
->sched_class
->pre_schedule(rq
, prev
);
2794 /* rq->lock is NOT held, but preemption is disabled */
2795 static inline void post_schedule(struct rq
*rq
)
2797 if (rq
->post_schedule
) {
2798 unsigned long flags
;
2800 raw_spin_lock_irqsave(&rq
->lock
, flags
);
2801 if (rq
->curr
->sched_class
->post_schedule
)
2802 rq
->curr
->sched_class
->post_schedule(rq
);
2803 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
2805 rq
->post_schedule
= 0;
2811 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*p
)
2815 static inline void post_schedule(struct rq
*rq
)
2822 * schedule_tail - first thing a freshly forked thread must call.
2823 * @prev: the thread we just switched away from.
2825 asmlinkage
void schedule_tail(struct task_struct
*prev
)
2826 __releases(rq
->lock
)
2828 struct rq
*rq
= this_rq();
2830 finish_task_switch(rq
, prev
);
2833 * FIXME: do we need to worry about rq being invalidated by the
2838 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2839 /* In this case, finish_task_switch does not reenable preemption */
2842 if (current
->set_child_tid
)
2843 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2847 * context_switch - switch to the new MM and the new
2848 * thread's register state.
2851 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2852 struct task_struct
*next
)
2854 struct mm_struct
*mm
, *oldmm
;
2856 prepare_task_switch(rq
, prev
, next
);
2857 trace_sched_switch(prev
, next
);
2859 oldmm
= prev
->active_mm
;
2861 * For paravirt, this is coupled with an exit in switch_to to
2862 * combine the page table reload and the switch backend into
2865 arch_start_context_switch(prev
);
2868 next
->active_mm
= oldmm
;
2869 atomic_inc(&oldmm
->mm_count
);
2870 enter_lazy_tlb(oldmm
, next
);
2872 switch_mm(oldmm
, mm
, next
);
2875 prev
->active_mm
= NULL
;
2876 rq
->prev_mm
= oldmm
;
2879 * Since the runqueue lock will be released by the next
2880 * task (which is an invalid locking op but in the case
2881 * of the scheduler it's an obvious special-case), so we
2882 * do an early lockdep release here:
2884 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2885 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2888 /* Here we just switch the register state and the stack. */
2889 switch_to(prev
, next
, prev
);
2893 * this_rq must be evaluated again because prev may have moved
2894 * CPUs since it called schedule(), thus the 'rq' on its stack
2895 * frame will be invalid.
2897 finish_task_switch(this_rq(), prev
);
2901 * nr_running, nr_uninterruptible and nr_context_switches:
2903 * externally visible scheduler statistics: current number of runnable
2904 * threads, current number of uninterruptible-sleeping threads, total
2905 * number of context switches performed since bootup.
2907 unsigned long nr_running(void)
2909 unsigned long i
, sum
= 0;
2911 for_each_online_cpu(i
)
2912 sum
+= cpu_rq(i
)->nr_running
;
2917 unsigned long nr_uninterruptible(void)
2919 unsigned long i
, sum
= 0;
2921 for_each_possible_cpu(i
)
2922 sum
+= cpu_rq(i
)->nr_uninterruptible
;
2925 * Since we read the counters lockless, it might be slightly
2926 * inaccurate. Do not allow it to go below zero though:
2928 if (unlikely((long)sum
< 0))
2934 unsigned long long nr_context_switches(void)
2937 unsigned long long sum
= 0;
2939 for_each_possible_cpu(i
)
2940 sum
+= cpu_rq(i
)->nr_switches
;
2945 unsigned long nr_iowait(void)
2947 unsigned long i
, sum
= 0;
2949 for_each_possible_cpu(i
)
2950 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2955 unsigned long nr_iowait_cpu(int cpu
)
2957 struct rq
*this = cpu_rq(cpu
);
2958 return atomic_read(&this->nr_iowait
);
2961 unsigned long this_cpu_load(void)
2963 struct rq
*this = this_rq();
2964 return this->cpu_load
[0];
2968 /* Variables and functions for calc_load */
2969 static atomic_long_t calc_load_tasks
;
2970 static unsigned long calc_load_update
;
2971 unsigned long avenrun
[3];
2972 EXPORT_SYMBOL(avenrun
);
2974 static long calc_load_fold_active(struct rq
*this_rq
)
2976 long nr_active
, delta
= 0;
2978 nr_active
= this_rq
->nr_running
;
2979 nr_active
+= (long) this_rq
->nr_uninterruptible
;
2981 if (nr_active
!= this_rq
->calc_load_active
) {
2982 delta
= nr_active
- this_rq
->calc_load_active
;
2983 this_rq
->calc_load_active
= nr_active
;
2991 * For NO_HZ we delay the active fold to the next LOAD_FREQ update.
2993 * When making the ILB scale, we should try to pull this in as well.
2995 static atomic_long_t calc_load_tasks_idle
;
2997 static void calc_load_account_idle(struct rq
*this_rq
)
3001 delta
= calc_load_fold_active(this_rq
);
3003 atomic_long_add(delta
, &calc_load_tasks_idle
);
3006 static long calc_load_fold_idle(void)
3011 * Its got a race, we don't care...
3013 if (atomic_long_read(&calc_load_tasks_idle
))
3014 delta
= atomic_long_xchg(&calc_load_tasks_idle
, 0);
3019 static void calc_load_account_idle(struct rq
*this_rq
)
3023 static inline long calc_load_fold_idle(void)
3030 * get_avenrun - get the load average array
3031 * @loads: pointer to dest load array
3032 * @offset: offset to add
3033 * @shift: shift count to shift the result left
3035 * These values are estimates at best, so no need for locking.
3037 void get_avenrun(unsigned long *loads
, unsigned long offset
, int shift
)
3039 loads
[0] = (avenrun
[0] + offset
) << shift
;
3040 loads
[1] = (avenrun
[1] + offset
) << shift
;
3041 loads
[2] = (avenrun
[2] + offset
) << shift
;
3044 static unsigned long
3045 calc_load(unsigned long load
, unsigned long exp
, unsigned long active
)
3048 load
+= active
* (FIXED_1
- exp
);
3049 return load
>> FSHIFT
;
3053 * calc_load - update the avenrun load estimates 10 ticks after the
3054 * CPUs have updated calc_load_tasks.
3056 void calc_global_load(void)
3058 unsigned long upd
= calc_load_update
+ 10;
3061 if (time_before(jiffies
, upd
))
3064 active
= atomic_long_read(&calc_load_tasks
);
3065 active
= active
> 0 ? active
* FIXED_1
: 0;
3067 avenrun
[0] = calc_load(avenrun
[0], EXP_1
, active
);
3068 avenrun
[1] = calc_load(avenrun
[1], EXP_5
, active
);
3069 avenrun
[2] = calc_load(avenrun
[2], EXP_15
, active
);
3071 calc_load_update
+= LOAD_FREQ
;
3075 * Called from update_cpu_load() to periodically update this CPU's
3078 static void calc_load_account_active(struct rq
*this_rq
)
3082 if (time_before(jiffies
, this_rq
->calc_load_update
))
3085 delta
= calc_load_fold_active(this_rq
);
3086 delta
+= calc_load_fold_idle();
3088 atomic_long_add(delta
, &calc_load_tasks
);
3090 this_rq
->calc_load_update
+= LOAD_FREQ
;
3094 * The exact cpuload at various idx values, calculated at every tick would be
3095 * load = (2^idx - 1) / 2^idx * load + 1 / 2^idx * cur_load
3097 * If a cpu misses updates for n-1 ticks (as it was idle) and update gets called
3098 * on nth tick when cpu may be busy, then we have:
3099 * load = ((2^idx - 1) / 2^idx)^(n-1) * load
3100 * load = (2^idx - 1) / 2^idx) * load + 1 / 2^idx * cur_load
3102 * decay_load_missed() below does efficient calculation of
3103 * load = ((2^idx - 1) / 2^idx)^(n-1) * load
3104 * avoiding 0..n-1 loop doing load = ((2^idx - 1) / 2^idx) * load
3106 * The calculation is approximated on a 128 point scale.
3107 * degrade_zero_ticks is the number of ticks after which load at any
3108 * particular idx is approximated to be zero.
3109 * degrade_factor is a precomputed table, a row for each load idx.
3110 * Each column corresponds to degradation factor for a power of two ticks,
3111 * based on 128 point scale.
3113 * row 2, col 3 (=12) says that the degradation at load idx 2 after
3114 * 8 ticks is 12/128 (which is an approximation of exact factor 3^8/4^8).
3116 * With this power of 2 load factors, we can degrade the load n times
3117 * by looking at 1 bits in n and doing as many mult/shift instead of
3118 * n mult/shifts needed by the exact degradation.
3120 #define DEGRADE_SHIFT 7
3121 static const unsigned char
3122 degrade_zero_ticks
[CPU_LOAD_IDX_MAX
] = {0, 8, 32, 64, 128};
3123 static const unsigned char
3124 degrade_factor
[CPU_LOAD_IDX_MAX
][DEGRADE_SHIFT
+ 1] = {
3125 {0, 0, 0, 0, 0, 0, 0, 0},
3126 {64, 32, 8, 0, 0, 0, 0, 0},
3127 {96, 72, 40, 12, 1, 0, 0},
3128 {112, 98, 75, 43, 15, 1, 0},
3129 {120, 112, 98, 76, 45, 16, 2} };
3132 * Update cpu_load for any missed ticks, due to tickless idle. The backlog
3133 * would be when CPU is idle and so we just decay the old load without
3134 * adding any new load.
3136 static unsigned long
3137 decay_load_missed(unsigned long load
, unsigned long missed_updates
, int idx
)
3141 if (!missed_updates
)
3144 if (missed_updates
>= degrade_zero_ticks
[idx
])
3148 return load
>> missed_updates
;
3150 while (missed_updates
) {
3151 if (missed_updates
% 2)
3152 load
= (load
* degrade_factor
[idx
][j
]) >> DEGRADE_SHIFT
;
3154 missed_updates
>>= 1;
3161 * Update rq->cpu_load[] statistics. This function is usually called every
3162 * scheduler tick (TICK_NSEC). With tickless idle this will not be called
3163 * every tick. We fix it up based on jiffies.
3165 static void update_cpu_load(struct rq
*this_rq
)
3167 unsigned long this_load
= this_rq
->load
.weight
;
3168 unsigned long curr_jiffies
= jiffies
;
3169 unsigned long pending_updates
;
3172 this_rq
->nr_load_updates
++;
3174 /* Avoid repeated calls on same jiffy, when moving in and out of idle */
3175 if (curr_jiffies
== this_rq
->last_load_update_tick
)
3178 pending_updates
= curr_jiffies
- this_rq
->last_load_update_tick
;
3179 this_rq
->last_load_update_tick
= curr_jiffies
;
3181 /* Update our load: */
3182 this_rq
->cpu_load
[0] = this_load
; /* Fasttrack for idx 0 */
3183 for (i
= 1, scale
= 2; i
< CPU_LOAD_IDX_MAX
; i
++, scale
+= scale
) {
3184 unsigned long old_load
, new_load
;
3186 /* scale is effectively 1 << i now, and >> i divides by scale */
3188 old_load
= this_rq
->cpu_load
[i
];
3189 old_load
= decay_load_missed(old_load
, pending_updates
- 1, i
);
3190 new_load
= this_load
;
3192 * Round up the averaging division if load is increasing. This
3193 * prevents us from getting stuck on 9 if the load is 10, for
3196 if (new_load
> old_load
)
3197 new_load
+= scale
- 1;
3199 this_rq
->cpu_load
[i
] = (old_load
* (scale
- 1) + new_load
) >> i
;
3202 sched_avg_update(this_rq
);
3205 static void update_cpu_load_active(struct rq
*this_rq
)
3207 update_cpu_load(this_rq
);
3209 calc_load_account_active(this_rq
);
3215 * sched_exec - execve() is a valuable balancing opportunity, because at
3216 * this point the task has the smallest effective memory and cache footprint.
3218 void sched_exec(void)
3220 struct task_struct
*p
= current
;
3221 unsigned long flags
;
3225 rq
= task_rq_lock(p
, &flags
);
3226 dest_cpu
= p
->sched_class
->select_task_rq(rq
, p
, SD_BALANCE_EXEC
, 0);
3227 if (dest_cpu
== smp_processor_id())
3231 * select_task_rq() can race against ->cpus_allowed
3233 if (cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
) &&
3234 likely(cpu_active(dest_cpu
)) && migrate_task(p
, rq
)) {
3235 struct migration_arg arg
= { p
, dest_cpu
};
3237 task_rq_unlock(rq
, &flags
);
3238 stop_one_cpu(cpu_of(rq
), migration_cpu_stop
, &arg
);
3242 task_rq_unlock(rq
, &flags
);
3247 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
3249 EXPORT_PER_CPU_SYMBOL(kstat
);
3252 * Return any ns on the sched_clock that have not yet been accounted in
3253 * @p in case that task is currently running.
3255 * Called with task_rq_lock() held on @rq.
3257 static u64
do_task_delta_exec(struct task_struct
*p
, struct rq
*rq
)
3261 if (task_current(rq
, p
)) {
3262 update_rq_clock(rq
);
3263 ns
= rq
->clock_task
- p
->se
.exec_start
;
3271 unsigned long long task_delta_exec(struct task_struct
*p
)
3273 unsigned long flags
;
3277 rq
= task_rq_lock(p
, &flags
);
3278 ns
= do_task_delta_exec(p
, rq
);
3279 task_rq_unlock(rq
, &flags
);
3285 * Return accounted runtime for the task.
3286 * In case the task is currently running, return the runtime plus current's
3287 * pending runtime that have not been accounted yet.
3289 unsigned long long task_sched_runtime(struct task_struct
*p
)
3291 unsigned long flags
;
3295 rq
= task_rq_lock(p
, &flags
);
3296 ns
= p
->se
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
3297 task_rq_unlock(rq
, &flags
);
3303 * Return sum_exec_runtime for the thread group.
3304 * In case the task is currently running, return the sum plus current's
3305 * pending runtime that have not been accounted yet.
3307 * Note that the thread group might have other running tasks as well,
3308 * so the return value not includes other pending runtime that other
3309 * running tasks might have.
3311 unsigned long long thread_group_sched_runtime(struct task_struct
*p
)
3313 struct task_cputime totals
;
3314 unsigned long flags
;
3318 rq
= task_rq_lock(p
, &flags
);
3319 thread_group_cputime(p
, &totals
);
3320 ns
= totals
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
3321 task_rq_unlock(rq
, &flags
);
3327 * Account user cpu time to a process.
3328 * @p: the process that the cpu time gets accounted to
3329 * @cputime: the cpu time spent in user space since the last update
3330 * @cputime_scaled: cputime scaled by cpu frequency
3332 void account_user_time(struct task_struct
*p
, cputime_t cputime
,
3333 cputime_t cputime_scaled
)
3335 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3338 /* Add user time to process. */
3339 p
->utime
= cputime_add(p
->utime
, cputime
);
3340 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
3341 account_group_user_time(p
, cputime
);
3343 /* Add user time to cpustat. */
3344 tmp
= cputime_to_cputime64(cputime
);
3345 if (TASK_NICE(p
) > 0)
3346 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
3348 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
3350 cpuacct_update_stats(p
, CPUACCT_STAT_USER
, cputime
);
3351 /* Account for user time used */
3352 acct_update_integrals(p
);
3356 * Account guest cpu time to a process.
3357 * @p: the process that the cpu time gets accounted to
3358 * @cputime: the cpu time spent in virtual machine since the last update
3359 * @cputime_scaled: cputime scaled by cpu frequency
3361 static void account_guest_time(struct task_struct
*p
, cputime_t cputime
,
3362 cputime_t cputime_scaled
)
3365 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3367 tmp
= cputime_to_cputime64(cputime
);
3369 /* Add guest time to process. */
3370 p
->utime
= cputime_add(p
->utime
, cputime
);
3371 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
3372 account_group_user_time(p
, cputime
);
3373 p
->gtime
= cputime_add(p
->gtime
, cputime
);
3375 /* Add guest time to cpustat. */
3376 if (TASK_NICE(p
) > 0) {
3377 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
3378 cpustat
->guest_nice
= cputime64_add(cpustat
->guest_nice
, tmp
);
3380 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
3381 cpustat
->guest
= cputime64_add(cpustat
->guest
, tmp
);
3386 * Account system cpu time to a process.
3387 * @p: the process that the cpu time gets accounted to
3388 * @hardirq_offset: the offset to subtract from hardirq_count()
3389 * @cputime: the cpu time spent in kernel space since the last update
3390 * @cputime_scaled: cputime scaled by cpu frequency
3392 void account_system_time(struct task_struct
*p
, int hardirq_offset
,
3393 cputime_t cputime
, cputime_t cputime_scaled
)
3395 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3398 if ((p
->flags
& PF_VCPU
) && (irq_count() - hardirq_offset
== 0)) {
3399 account_guest_time(p
, cputime
, cputime_scaled
);
3403 /* Add system time to process. */
3404 p
->stime
= cputime_add(p
->stime
, cputime
);
3405 p
->stimescaled
= cputime_add(p
->stimescaled
, cputime_scaled
);
3406 account_group_system_time(p
, cputime
);
3408 /* Add system time to cpustat. */
3409 tmp
= cputime_to_cputime64(cputime
);
3410 if (hardirq_count() - hardirq_offset
)
3411 cpustat
->irq
= cputime64_add(cpustat
->irq
, tmp
);
3412 else if (in_serving_softirq())
3413 cpustat
->softirq
= cputime64_add(cpustat
->softirq
, tmp
);
3415 cpustat
->system
= cputime64_add(cpustat
->system
, tmp
);
3417 cpuacct_update_stats(p
, CPUACCT_STAT_SYSTEM
, cputime
);
3419 /* Account for system time used */
3420 acct_update_integrals(p
);
3424 * Account for involuntary wait time.
3425 * @steal: the cpu time spent in involuntary wait
3427 void account_steal_time(cputime_t cputime
)
3429 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3430 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
3432 cpustat
->steal
= cputime64_add(cpustat
->steal
, cputime64
);
3436 * Account for idle time.
3437 * @cputime: the cpu time spent in idle wait
3439 void account_idle_time(cputime_t cputime
)
3441 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3442 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
3443 struct rq
*rq
= this_rq();
3445 if (atomic_read(&rq
->nr_iowait
) > 0)
3446 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, cputime64
);
3448 cpustat
->idle
= cputime64_add(cpustat
->idle
, cputime64
);
3451 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
3454 * Account a single tick of cpu time.
3455 * @p: the process that the cpu time gets accounted to
3456 * @user_tick: indicates if the tick is a user or a system tick
3458 void account_process_tick(struct task_struct
*p
, int user_tick
)
3460 cputime_t one_jiffy_scaled
= cputime_to_scaled(cputime_one_jiffy
);
3461 struct rq
*rq
= this_rq();
3464 account_user_time(p
, cputime_one_jiffy
, one_jiffy_scaled
);
3465 else if ((p
!= rq
->idle
) || (irq_count() != HARDIRQ_OFFSET
))
3466 account_system_time(p
, HARDIRQ_OFFSET
, cputime_one_jiffy
,
3469 account_idle_time(cputime_one_jiffy
);
3473 * Account multiple ticks of steal time.
3474 * @p: the process from which the cpu time has been stolen
3475 * @ticks: number of stolen ticks
3477 void account_steal_ticks(unsigned long ticks
)
3479 account_steal_time(jiffies_to_cputime(ticks
));
3483 * Account multiple ticks of idle time.
3484 * @ticks: number of stolen ticks
3486 void account_idle_ticks(unsigned long ticks
)
3488 account_idle_time(jiffies_to_cputime(ticks
));
3494 * Use precise platform statistics if available:
3496 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
3497 void task_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
3503 void thread_group_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
3505 struct task_cputime cputime
;
3507 thread_group_cputime(p
, &cputime
);
3509 *ut
= cputime
.utime
;
3510 *st
= cputime
.stime
;
3514 #ifndef nsecs_to_cputime
3515 # define nsecs_to_cputime(__nsecs) nsecs_to_jiffies(__nsecs)
3518 void task_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
3520 cputime_t rtime
, utime
= p
->utime
, total
= cputime_add(utime
, p
->stime
);
3523 * Use CFS's precise accounting:
3525 rtime
= nsecs_to_cputime(p
->se
.sum_exec_runtime
);
3531 do_div(temp
, total
);
3532 utime
= (cputime_t
)temp
;
3537 * Compare with previous values, to keep monotonicity:
3539 p
->prev_utime
= max(p
->prev_utime
, utime
);
3540 p
->prev_stime
= max(p
->prev_stime
, cputime_sub(rtime
, p
->prev_utime
));
3542 *ut
= p
->prev_utime
;
3543 *st
= p
->prev_stime
;
3547 * Must be called with siglock held.
3549 void thread_group_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
3551 struct signal_struct
*sig
= p
->signal
;
3552 struct task_cputime cputime
;
3553 cputime_t rtime
, utime
, total
;
3555 thread_group_cputime(p
, &cputime
);
3557 total
= cputime_add(cputime
.utime
, cputime
.stime
);
3558 rtime
= nsecs_to_cputime(cputime
.sum_exec_runtime
);
3563 temp
*= cputime
.utime
;
3564 do_div(temp
, total
);
3565 utime
= (cputime_t
)temp
;
3569 sig
->prev_utime
= max(sig
->prev_utime
, utime
);
3570 sig
->prev_stime
= max(sig
->prev_stime
,
3571 cputime_sub(rtime
, sig
->prev_utime
));
3573 *ut
= sig
->prev_utime
;
3574 *st
= sig
->prev_stime
;
3579 * This function gets called by the timer code, with HZ frequency.
3580 * We call it with interrupts disabled.
3582 * It also gets called by the fork code, when changing the parent's
3585 void scheduler_tick(void)
3587 int cpu
= smp_processor_id();
3588 struct rq
*rq
= cpu_rq(cpu
);
3589 struct task_struct
*curr
= rq
->curr
;
3593 raw_spin_lock(&rq
->lock
);
3594 update_rq_clock(rq
);
3595 update_cpu_load_active(rq
);
3596 curr
->sched_class
->task_tick(rq
, curr
, 0);
3597 raw_spin_unlock(&rq
->lock
);
3599 perf_event_task_tick();
3602 rq
->idle_at_tick
= idle_cpu(cpu
);
3603 trigger_load_balance(rq
, cpu
);
3607 notrace
unsigned long get_parent_ip(unsigned long addr
)
3609 if (in_lock_functions(addr
)) {
3610 addr
= CALLER_ADDR2
;
3611 if (in_lock_functions(addr
))
3612 addr
= CALLER_ADDR3
;
3617 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
3618 defined(CONFIG_PREEMPT_TRACER))
3620 void __kprobes
add_preempt_count(int val
)
3622 #ifdef CONFIG_DEBUG_PREEMPT
3626 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
3629 preempt_count() += val
;
3630 #ifdef CONFIG_DEBUG_PREEMPT
3632 * Spinlock count overflowing soon?
3634 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
3637 if (preempt_count() == val
)
3638 trace_preempt_off(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
3640 EXPORT_SYMBOL(add_preempt_count
);
3642 void __kprobes
sub_preempt_count(int val
)
3644 #ifdef CONFIG_DEBUG_PREEMPT
3648 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
3651 * Is the spinlock portion underflowing?
3653 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
3654 !(preempt_count() & PREEMPT_MASK
)))
3658 if (preempt_count() == val
)
3659 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
3660 preempt_count() -= val
;
3662 EXPORT_SYMBOL(sub_preempt_count
);
3667 * Print scheduling while atomic bug:
3669 static noinline
void __schedule_bug(struct task_struct
*prev
)
3671 struct pt_regs
*regs
= get_irq_regs();
3673 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
3674 prev
->comm
, prev
->pid
, preempt_count());
3676 debug_show_held_locks(prev
);
3678 if (irqs_disabled())
3679 print_irqtrace_events(prev
);
3688 * Various schedule()-time debugging checks and statistics:
3690 static inline void schedule_debug(struct task_struct
*prev
)
3693 * Test if we are atomic. Since do_exit() needs to call into
3694 * schedule() atomically, we ignore that path for now.
3695 * Otherwise, whine if we are scheduling when we should not be.
3697 if (unlikely(in_atomic_preempt_off() && !prev
->exit_state
))
3698 __schedule_bug(prev
);
3700 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
3702 schedstat_inc(this_rq(), sched_count
);
3703 #ifdef CONFIG_SCHEDSTATS
3704 if (unlikely(prev
->lock_depth
>= 0)) {
3705 schedstat_inc(this_rq(), bkl_count
);
3706 schedstat_inc(prev
, sched_info
.bkl_count
);
3711 static void put_prev_task(struct rq
*rq
, struct task_struct
*prev
)
3714 update_rq_clock(rq
);
3715 rq
->skip_clock_update
= 0;
3716 prev
->sched_class
->put_prev_task(rq
, prev
);
3720 * Pick up the highest-prio task:
3722 static inline struct task_struct
*
3723 pick_next_task(struct rq
*rq
)
3725 const struct sched_class
*class;
3726 struct task_struct
*p
;
3729 * Optimization: we know that if all tasks are in
3730 * the fair class we can call that function directly:
3732 if (likely(rq
->nr_running
== rq
->cfs
.nr_running
)) {
3733 p
= fair_sched_class
.pick_next_task(rq
);
3738 for_each_class(class) {
3739 p
= class->pick_next_task(rq
);
3744 BUG(); /* the idle class will always have a runnable task */
3748 * schedule() is the main scheduler function.
3750 asmlinkage
void __sched
schedule(void)
3752 struct task_struct
*prev
, *next
;
3753 unsigned long *switch_count
;
3759 cpu
= smp_processor_id();
3761 rcu_note_context_switch(cpu
);
3764 release_kernel_lock(prev
);
3765 need_resched_nonpreemptible
:
3767 schedule_debug(prev
);
3769 if (sched_feat(HRTICK
))
3772 raw_spin_lock_irq(&rq
->lock
);
3773 clear_tsk_need_resched(prev
);
3775 switch_count
= &prev
->nivcsw
;
3776 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
3777 if (unlikely(signal_pending_state(prev
->state
, prev
))) {
3778 prev
->state
= TASK_RUNNING
;
3781 * If a worker is going to sleep, notify and
3782 * ask workqueue whether it wants to wake up a
3783 * task to maintain concurrency. If so, wake
3786 if (prev
->flags
& PF_WQ_WORKER
) {
3787 struct task_struct
*to_wakeup
;
3789 to_wakeup
= wq_worker_sleeping(prev
, cpu
);
3791 try_to_wake_up_local(to_wakeup
);
3793 deactivate_task(rq
, prev
, DEQUEUE_SLEEP
);
3795 switch_count
= &prev
->nvcsw
;
3798 pre_schedule(rq
, prev
);
3800 if (unlikely(!rq
->nr_running
))
3801 idle_balance(cpu
, rq
);
3803 put_prev_task(rq
, prev
);
3804 next
= pick_next_task(rq
);
3806 if (likely(prev
!= next
)) {
3807 sched_info_switch(prev
, next
);
3808 perf_event_task_sched_out(prev
, next
);
3814 context_switch(rq
, prev
, next
); /* unlocks the rq */
3816 * The context switch have flipped the stack from under us
3817 * and restored the local variables which were saved when
3818 * this task called schedule() in the past. prev == current
3819 * is still correct, but it can be moved to another cpu/rq.
3821 cpu
= smp_processor_id();
3824 raw_spin_unlock_irq(&rq
->lock
);
3828 if (unlikely(reacquire_kernel_lock(prev
)))
3829 goto need_resched_nonpreemptible
;
3831 preempt_enable_no_resched();
3835 EXPORT_SYMBOL(schedule
);
3837 #ifdef CONFIG_MUTEX_SPIN_ON_OWNER
3839 * Look out! "owner" is an entirely speculative pointer
3840 * access and not reliable.
3842 int mutex_spin_on_owner(struct mutex
*lock
, struct thread_info
*owner
)
3847 if (!sched_feat(OWNER_SPIN
))
3850 #ifdef CONFIG_DEBUG_PAGEALLOC
3852 * Need to access the cpu field knowing that
3853 * DEBUG_PAGEALLOC could have unmapped it if
3854 * the mutex owner just released it and exited.
3856 if (probe_kernel_address(&owner
->cpu
, cpu
))
3863 * Even if the access succeeded (likely case),
3864 * the cpu field may no longer be valid.
3866 if (cpu
>= nr_cpumask_bits
)
3870 * We need to validate that we can do a
3871 * get_cpu() and that we have the percpu area.
3873 if (!cpu_online(cpu
))
3880 * Owner changed, break to re-assess state.
3882 if (lock
->owner
!= owner
) {
3884 * If the lock has switched to a different owner,
3885 * we likely have heavy contention. Return 0 to quit
3886 * optimistic spinning and not contend further:
3894 * Is that owner really running on that cpu?
3896 if (task_thread_info(rq
->curr
) != owner
|| need_resched())
3899 arch_mutex_cpu_relax();
3906 #ifdef CONFIG_PREEMPT
3908 * this is the entry point to schedule() from in-kernel preemption
3909 * off of preempt_enable. Kernel preemptions off return from interrupt
3910 * occur there and call schedule directly.
3912 asmlinkage
void __sched notrace
preempt_schedule(void)
3914 struct thread_info
*ti
= current_thread_info();
3917 * If there is a non-zero preempt_count or interrupts are disabled,
3918 * we do not want to preempt the current task. Just return..
3920 if (likely(ti
->preempt_count
|| irqs_disabled()))
3924 add_preempt_count_notrace(PREEMPT_ACTIVE
);
3926 sub_preempt_count_notrace(PREEMPT_ACTIVE
);
3929 * Check again in case we missed a preemption opportunity
3930 * between schedule and now.
3933 } while (need_resched());
3935 EXPORT_SYMBOL(preempt_schedule
);
3938 * this is the entry point to schedule() from kernel preemption
3939 * off of irq context.
3940 * Note, that this is called and return with irqs disabled. This will
3941 * protect us against recursive calling from irq.
3943 asmlinkage
void __sched
preempt_schedule_irq(void)
3945 struct thread_info
*ti
= current_thread_info();
3947 /* Catch callers which need to be fixed */
3948 BUG_ON(ti
->preempt_count
|| !irqs_disabled());
3951 add_preempt_count(PREEMPT_ACTIVE
);
3954 local_irq_disable();
3955 sub_preempt_count(PREEMPT_ACTIVE
);
3958 * Check again in case we missed a preemption opportunity
3959 * between schedule and now.
3962 } while (need_resched());
3965 #endif /* CONFIG_PREEMPT */
3967 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int wake_flags
,
3970 return try_to_wake_up(curr
->private, mode
, wake_flags
);
3972 EXPORT_SYMBOL(default_wake_function
);
3975 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
3976 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
3977 * number) then we wake all the non-exclusive tasks and one exclusive task.
3979 * There are circumstances in which we can try to wake a task which has already
3980 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
3981 * zero in this (rare) case, and we handle it by continuing to scan the queue.
3983 static void __wake_up_common(wait_queue_head_t
*q
, unsigned int mode
,
3984 int nr_exclusive
, int wake_flags
, void *key
)
3986 wait_queue_t
*curr
, *next
;
3988 list_for_each_entry_safe(curr
, next
, &q
->task_list
, task_list
) {
3989 unsigned flags
= curr
->flags
;
3991 if (curr
->func(curr
, mode
, wake_flags
, key
) &&
3992 (flags
& WQ_FLAG_EXCLUSIVE
) && !--nr_exclusive
)
3998 * __wake_up - wake up threads blocked on a waitqueue.
4000 * @mode: which threads
4001 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4002 * @key: is directly passed to the wakeup function
4004 * It may be assumed that this function implies a write memory barrier before
4005 * changing the task state if and only if any tasks are woken up.
4007 void __wake_up(wait_queue_head_t
*q
, unsigned int mode
,
4008 int nr_exclusive
, void *key
)
4010 unsigned long flags
;
4012 spin_lock_irqsave(&q
->lock
, flags
);
4013 __wake_up_common(q
, mode
, nr_exclusive
, 0, key
);
4014 spin_unlock_irqrestore(&q
->lock
, flags
);
4016 EXPORT_SYMBOL(__wake_up
);
4019 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
4021 void __wake_up_locked(wait_queue_head_t
*q
, unsigned int mode
)
4023 __wake_up_common(q
, mode
, 1, 0, NULL
);
4025 EXPORT_SYMBOL_GPL(__wake_up_locked
);
4027 void __wake_up_locked_key(wait_queue_head_t
*q
, unsigned int mode
, void *key
)
4029 __wake_up_common(q
, mode
, 1, 0, key
);
4033 * __wake_up_sync_key - wake up threads blocked on a waitqueue.
4035 * @mode: which threads
4036 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4037 * @key: opaque value to be passed to wakeup targets
4039 * The sync wakeup differs that the waker knows that it will schedule
4040 * away soon, so while the target thread will be woken up, it will not
4041 * be migrated to another CPU - ie. the two threads are 'synchronized'
4042 * with each other. This can prevent needless bouncing between CPUs.
4044 * On UP it can prevent extra preemption.
4046 * It may be assumed that this function implies a write memory barrier before
4047 * changing the task state if and only if any tasks are woken up.
4049 void __wake_up_sync_key(wait_queue_head_t
*q
, unsigned int mode
,
4050 int nr_exclusive
, void *key
)
4052 unsigned long flags
;
4053 int wake_flags
= WF_SYNC
;
4058 if (unlikely(!nr_exclusive
))
4061 spin_lock_irqsave(&q
->lock
, flags
);
4062 __wake_up_common(q
, mode
, nr_exclusive
, wake_flags
, key
);
4063 spin_unlock_irqrestore(&q
->lock
, flags
);
4065 EXPORT_SYMBOL_GPL(__wake_up_sync_key
);
4068 * __wake_up_sync - see __wake_up_sync_key()
4070 void __wake_up_sync(wait_queue_head_t
*q
, unsigned int mode
, int nr_exclusive
)
4072 __wake_up_sync_key(q
, mode
, nr_exclusive
, NULL
);
4074 EXPORT_SYMBOL_GPL(__wake_up_sync
); /* For internal use only */
4077 * complete: - signals a single thread waiting on this completion
4078 * @x: holds the state of this particular completion
4080 * This will wake up a single thread waiting on this completion. Threads will be
4081 * awakened in the same order in which they were queued.
4083 * See also complete_all(), wait_for_completion() and related routines.
4085 * It may be assumed that this function implies a write memory barrier before
4086 * changing the task state if and only if any tasks are woken up.
4088 void complete(struct completion
*x
)
4090 unsigned long flags
;
4092 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4094 __wake_up_common(&x
->wait
, TASK_NORMAL
, 1, 0, NULL
);
4095 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4097 EXPORT_SYMBOL(complete
);
4100 * complete_all: - signals all threads waiting on this completion
4101 * @x: holds the state of this particular completion
4103 * This will wake up all threads waiting on this particular completion event.
4105 * It may be assumed that this function implies a write memory barrier before
4106 * changing the task state if and only if any tasks are woken up.
4108 void complete_all(struct completion
*x
)
4110 unsigned long flags
;
4112 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4113 x
->done
+= UINT_MAX
/2;
4114 __wake_up_common(&x
->wait
, TASK_NORMAL
, 0, 0, NULL
);
4115 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4117 EXPORT_SYMBOL(complete_all
);
4119 static inline long __sched
4120 do_wait_for_common(struct completion
*x
, long timeout
, int state
)
4123 DECLARE_WAITQUEUE(wait
, current
);
4125 __add_wait_queue_tail_exclusive(&x
->wait
, &wait
);
4127 if (signal_pending_state(state
, current
)) {
4128 timeout
= -ERESTARTSYS
;
4131 __set_current_state(state
);
4132 spin_unlock_irq(&x
->wait
.lock
);
4133 timeout
= schedule_timeout(timeout
);
4134 spin_lock_irq(&x
->wait
.lock
);
4135 } while (!x
->done
&& timeout
);
4136 __remove_wait_queue(&x
->wait
, &wait
);
4141 return timeout
?: 1;
4145 wait_for_common(struct completion
*x
, long timeout
, int state
)
4149 spin_lock_irq(&x
->wait
.lock
);
4150 timeout
= do_wait_for_common(x
, timeout
, state
);
4151 spin_unlock_irq(&x
->wait
.lock
);
4156 * wait_for_completion: - waits for completion of a task
4157 * @x: holds the state of this particular completion
4159 * This waits to be signaled for completion of a specific task. It is NOT
4160 * interruptible and there is no timeout.
4162 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
4163 * and interrupt capability. Also see complete().
4165 void __sched
wait_for_completion(struct completion
*x
)
4167 wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
4169 EXPORT_SYMBOL(wait_for_completion
);
4172 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
4173 * @x: holds the state of this particular completion
4174 * @timeout: timeout value in jiffies
4176 * This waits for either a completion of a specific task to be signaled or for a
4177 * specified timeout to expire. The timeout is in jiffies. It is not
4180 unsigned long __sched
4181 wait_for_completion_timeout(struct completion
*x
, unsigned long timeout
)
4183 return wait_for_common(x
, timeout
, TASK_UNINTERRUPTIBLE
);
4185 EXPORT_SYMBOL(wait_for_completion_timeout
);
4188 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
4189 * @x: holds the state of this particular completion
4191 * This waits for completion of a specific task to be signaled. It is
4194 int __sched
wait_for_completion_interruptible(struct completion
*x
)
4196 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_INTERRUPTIBLE
);
4197 if (t
== -ERESTARTSYS
)
4201 EXPORT_SYMBOL(wait_for_completion_interruptible
);
4204 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
4205 * @x: holds the state of this particular completion
4206 * @timeout: timeout value in jiffies
4208 * This waits for either a completion of a specific task to be signaled or for a
4209 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
4211 unsigned long __sched
4212 wait_for_completion_interruptible_timeout(struct completion
*x
,
4213 unsigned long timeout
)
4215 return wait_for_common(x
, timeout
, TASK_INTERRUPTIBLE
);
4217 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout
);
4220 * wait_for_completion_killable: - waits for completion of a task (killable)
4221 * @x: holds the state of this particular completion
4223 * This waits to be signaled for completion of a specific task. It can be
4224 * interrupted by a kill signal.
4226 int __sched
wait_for_completion_killable(struct completion
*x
)
4228 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_KILLABLE
);
4229 if (t
== -ERESTARTSYS
)
4233 EXPORT_SYMBOL(wait_for_completion_killable
);
4236 * wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable))
4237 * @x: holds the state of this particular completion
4238 * @timeout: timeout value in jiffies
4240 * This waits for either a completion of a specific task to be
4241 * signaled or for a specified timeout to expire. It can be
4242 * interrupted by a kill signal. The timeout is in jiffies.
4244 unsigned long __sched
4245 wait_for_completion_killable_timeout(struct completion
*x
,
4246 unsigned long timeout
)
4248 return wait_for_common(x
, timeout
, TASK_KILLABLE
);
4250 EXPORT_SYMBOL(wait_for_completion_killable_timeout
);
4253 * try_wait_for_completion - try to decrement a completion without blocking
4254 * @x: completion structure
4256 * Returns: 0 if a decrement cannot be done without blocking
4257 * 1 if a decrement succeeded.
4259 * If a completion is being used as a counting completion,
4260 * attempt to decrement the counter without blocking. This
4261 * enables us to avoid waiting if the resource the completion
4262 * is protecting is not available.
4264 bool try_wait_for_completion(struct completion
*x
)
4266 unsigned long flags
;
4269 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4274 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4277 EXPORT_SYMBOL(try_wait_for_completion
);
4280 * completion_done - Test to see if a completion has any waiters
4281 * @x: completion structure
4283 * Returns: 0 if there are waiters (wait_for_completion() in progress)
4284 * 1 if there are no waiters.
4287 bool completion_done(struct completion
*x
)
4289 unsigned long flags
;
4292 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4295 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4298 EXPORT_SYMBOL(completion_done
);
4301 sleep_on_common(wait_queue_head_t
*q
, int state
, long timeout
)
4303 unsigned long flags
;
4306 init_waitqueue_entry(&wait
, current
);
4308 __set_current_state(state
);
4310 spin_lock_irqsave(&q
->lock
, flags
);
4311 __add_wait_queue(q
, &wait
);
4312 spin_unlock(&q
->lock
);
4313 timeout
= schedule_timeout(timeout
);
4314 spin_lock_irq(&q
->lock
);
4315 __remove_wait_queue(q
, &wait
);
4316 spin_unlock_irqrestore(&q
->lock
, flags
);
4321 void __sched
interruptible_sleep_on(wait_queue_head_t
*q
)
4323 sleep_on_common(q
, TASK_INTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
4325 EXPORT_SYMBOL(interruptible_sleep_on
);
4328 interruptible_sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
4330 return sleep_on_common(q
, TASK_INTERRUPTIBLE
, timeout
);
4332 EXPORT_SYMBOL(interruptible_sleep_on_timeout
);
4334 void __sched
sleep_on(wait_queue_head_t
*q
)
4336 sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
4338 EXPORT_SYMBOL(sleep_on
);
4340 long __sched
sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
4342 return sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, timeout
);
4344 EXPORT_SYMBOL(sleep_on_timeout
);
4346 #ifdef CONFIG_RT_MUTEXES
4349 * rt_mutex_setprio - set the current priority of a task
4351 * @prio: prio value (kernel-internal form)
4353 * This function changes the 'effective' priority of a task. It does
4354 * not touch ->normal_prio like __setscheduler().
4356 * Used by the rt_mutex code to implement priority inheritance logic.
4358 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
4360 unsigned long flags
;
4361 int oldprio
, on_rq
, running
;
4363 const struct sched_class
*prev_class
;
4365 BUG_ON(prio
< 0 || prio
> MAX_PRIO
);
4367 rq
= task_rq_lock(p
, &flags
);
4369 trace_sched_pi_setprio(p
, prio
);
4371 prev_class
= p
->sched_class
;
4372 on_rq
= p
->se
.on_rq
;
4373 running
= task_current(rq
, p
);
4375 dequeue_task(rq
, p
, 0);
4377 p
->sched_class
->put_prev_task(rq
, p
);
4380 p
->sched_class
= &rt_sched_class
;
4382 p
->sched_class
= &fair_sched_class
;
4387 p
->sched_class
->set_curr_task(rq
);
4389 enqueue_task(rq
, p
, oldprio
< prio
? ENQUEUE_HEAD
: 0);
4391 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
4393 task_rq_unlock(rq
, &flags
);
4398 void set_user_nice(struct task_struct
*p
, long nice
)
4400 int old_prio
, delta
, on_rq
;
4401 unsigned long flags
;
4404 if (TASK_NICE(p
) == nice
|| nice
< -20 || nice
> 19)
4407 * We have to be careful, if called from sys_setpriority(),
4408 * the task might be in the middle of scheduling on another CPU.
4410 rq
= task_rq_lock(p
, &flags
);
4412 * The RT priorities are set via sched_setscheduler(), but we still
4413 * allow the 'normal' nice value to be set - but as expected
4414 * it wont have any effect on scheduling until the task is
4415 * SCHED_FIFO/SCHED_RR:
4417 if (task_has_rt_policy(p
)) {
4418 p
->static_prio
= NICE_TO_PRIO(nice
);
4421 on_rq
= p
->se
.on_rq
;
4423 dequeue_task(rq
, p
, 0);
4425 p
->static_prio
= NICE_TO_PRIO(nice
);
4428 p
->prio
= effective_prio(p
);
4429 delta
= p
->prio
- old_prio
;
4432 enqueue_task(rq
, p
, 0);
4434 * If the task increased its priority or is running and
4435 * lowered its priority, then reschedule its CPU:
4437 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
4438 resched_task(rq
->curr
);
4441 task_rq_unlock(rq
, &flags
);
4443 EXPORT_SYMBOL(set_user_nice
);
4446 * can_nice - check if a task can reduce its nice value
4450 int can_nice(const struct task_struct
*p
, const int nice
)
4452 /* convert nice value [19,-20] to rlimit style value [1,40] */
4453 int nice_rlim
= 20 - nice
;
4455 return (nice_rlim
<= task_rlimit(p
, RLIMIT_NICE
) ||
4456 capable(CAP_SYS_NICE
));
4459 #ifdef __ARCH_WANT_SYS_NICE
4462 * sys_nice - change the priority of the current process.
4463 * @increment: priority increment
4465 * sys_setpriority is a more generic, but much slower function that
4466 * does similar things.
4468 SYSCALL_DEFINE1(nice
, int, increment
)
4473 * Setpriority might change our priority at the same moment.
4474 * We don't have to worry. Conceptually one call occurs first
4475 * and we have a single winner.
4477 if (increment
< -40)
4482 nice
= TASK_NICE(current
) + increment
;
4488 if (increment
< 0 && !can_nice(current
, nice
))
4491 retval
= security_task_setnice(current
, nice
);
4495 set_user_nice(current
, nice
);
4502 * task_prio - return the priority value of a given task.
4503 * @p: the task in question.
4505 * This is the priority value as seen by users in /proc.
4506 * RT tasks are offset by -200. Normal tasks are centered
4507 * around 0, value goes from -16 to +15.
4509 int task_prio(const struct task_struct
*p
)
4511 return p
->prio
- MAX_RT_PRIO
;
4515 * task_nice - return the nice value of a given task.
4516 * @p: the task in question.
4518 int task_nice(const struct task_struct
*p
)
4520 return TASK_NICE(p
);
4522 EXPORT_SYMBOL(task_nice
);
4525 * idle_cpu - is a given cpu idle currently?
4526 * @cpu: the processor in question.
4528 int idle_cpu(int cpu
)
4530 return cpu_curr(cpu
) == cpu_rq(cpu
)->idle
;
4534 * idle_task - return the idle task for a given cpu.
4535 * @cpu: the processor in question.
4537 struct task_struct
*idle_task(int cpu
)
4539 return cpu_rq(cpu
)->idle
;
4543 * find_process_by_pid - find a process with a matching PID value.
4544 * @pid: the pid in question.
4546 static struct task_struct
*find_process_by_pid(pid_t pid
)
4548 return pid
? find_task_by_vpid(pid
) : current
;
4551 /* Actually do priority change: must hold rq lock. */
4553 __setscheduler(struct rq
*rq
, struct task_struct
*p
, int policy
, int prio
)
4555 BUG_ON(p
->se
.on_rq
);
4558 p
->rt_priority
= prio
;
4559 p
->normal_prio
= normal_prio(p
);
4560 /* we are holding p->pi_lock already */
4561 p
->prio
= rt_mutex_getprio(p
);
4562 if (rt_prio(p
->prio
))
4563 p
->sched_class
= &rt_sched_class
;
4565 p
->sched_class
= &fair_sched_class
;
4570 * check the target process has a UID that matches the current process's
4572 static bool check_same_owner(struct task_struct
*p
)
4574 const struct cred
*cred
= current_cred(), *pcred
;
4578 pcred
= __task_cred(p
);
4579 match
= (cred
->euid
== pcred
->euid
||
4580 cred
->euid
== pcred
->uid
);
4585 static int __sched_setscheduler(struct task_struct
*p
, int policy
,
4586 const struct sched_param
*param
, bool user
)
4588 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
4589 unsigned long flags
;
4590 const struct sched_class
*prev_class
;
4594 /* may grab non-irq protected spin_locks */
4595 BUG_ON(in_interrupt());
4597 /* double check policy once rq lock held */
4599 reset_on_fork
= p
->sched_reset_on_fork
;
4600 policy
= oldpolicy
= p
->policy
;
4602 reset_on_fork
= !!(policy
& SCHED_RESET_ON_FORK
);
4603 policy
&= ~SCHED_RESET_ON_FORK
;
4605 if (policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
4606 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
4607 policy
!= SCHED_IDLE
)
4612 * Valid priorities for SCHED_FIFO and SCHED_RR are
4613 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
4614 * SCHED_BATCH and SCHED_IDLE is 0.
4616 if (param
->sched_priority
< 0 ||
4617 (p
->mm
&& param
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
4618 (!p
->mm
&& param
->sched_priority
> MAX_RT_PRIO
-1))
4620 if (rt_policy(policy
) != (param
->sched_priority
!= 0))
4624 * Allow unprivileged RT tasks to decrease priority:
4626 if (user
&& !capable(CAP_SYS_NICE
)) {
4627 if (rt_policy(policy
)) {
4628 unsigned long rlim_rtprio
=
4629 task_rlimit(p
, RLIMIT_RTPRIO
);
4631 /* can't set/change the rt policy */
4632 if (policy
!= p
->policy
&& !rlim_rtprio
)
4635 /* can't increase priority */
4636 if (param
->sched_priority
> p
->rt_priority
&&
4637 param
->sched_priority
> rlim_rtprio
)
4641 * Like positive nice levels, dont allow tasks to
4642 * move out of SCHED_IDLE either:
4644 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
)
4647 /* can't change other user's priorities */
4648 if (!check_same_owner(p
))
4651 /* Normal users shall not reset the sched_reset_on_fork flag */
4652 if (p
->sched_reset_on_fork
&& !reset_on_fork
)
4657 retval
= security_task_setscheduler(p
);
4663 * make sure no PI-waiters arrive (or leave) while we are
4664 * changing the priority of the task:
4666 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
4668 * To be able to change p->policy safely, the apropriate
4669 * runqueue lock must be held.
4671 rq
= __task_rq_lock(p
);
4674 * Changing the policy of the stop threads its a very bad idea
4676 if (p
== rq
->stop
) {
4677 __task_rq_unlock(rq
);
4678 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4682 #ifdef CONFIG_RT_GROUP_SCHED
4685 * Do not allow realtime tasks into groups that have no runtime
4688 if (rt_bandwidth_enabled() && rt_policy(policy
) &&
4689 task_group(p
)->rt_bandwidth
.rt_runtime
== 0) {
4690 __task_rq_unlock(rq
);
4691 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4697 /* recheck policy now with rq lock held */
4698 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
4699 policy
= oldpolicy
= -1;
4700 __task_rq_unlock(rq
);
4701 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4704 on_rq
= p
->se
.on_rq
;
4705 running
= task_current(rq
, p
);
4707 deactivate_task(rq
, p
, 0);
4709 p
->sched_class
->put_prev_task(rq
, p
);
4711 p
->sched_reset_on_fork
= reset_on_fork
;
4714 prev_class
= p
->sched_class
;
4715 __setscheduler(rq
, p
, policy
, param
->sched_priority
);
4718 p
->sched_class
->set_curr_task(rq
);
4720 activate_task(rq
, p
, 0);
4722 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
4724 __task_rq_unlock(rq
);
4725 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4727 rt_mutex_adjust_pi(p
);
4733 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
4734 * @p: the task in question.
4735 * @policy: new policy.
4736 * @param: structure containing the new RT priority.
4738 * NOTE that the task may be already dead.
4740 int sched_setscheduler(struct task_struct
*p
, int policy
,
4741 const struct sched_param
*param
)
4743 return __sched_setscheduler(p
, policy
, param
, true);
4745 EXPORT_SYMBOL_GPL(sched_setscheduler
);
4748 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
4749 * @p: the task in question.
4750 * @policy: new policy.
4751 * @param: structure containing the new RT priority.
4753 * Just like sched_setscheduler, only don't bother checking if the
4754 * current context has permission. For example, this is needed in
4755 * stop_machine(): we create temporary high priority worker threads,
4756 * but our caller might not have that capability.
4758 int sched_setscheduler_nocheck(struct task_struct
*p
, int policy
,
4759 const struct sched_param
*param
)
4761 return __sched_setscheduler(p
, policy
, param
, false);
4765 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
4767 struct sched_param lparam
;
4768 struct task_struct
*p
;
4771 if (!param
|| pid
< 0)
4773 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
4778 p
= find_process_by_pid(pid
);
4780 retval
= sched_setscheduler(p
, policy
, &lparam
);
4787 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
4788 * @pid: the pid in question.
4789 * @policy: new policy.
4790 * @param: structure containing the new RT priority.
4792 SYSCALL_DEFINE3(sched_setscheduler
, pid_t
, pid
, int, policy
,
4793 struct sched_param __user
*, param
)
4795 /* negative values for policy are not valid */
4799 return do_sched_setscheduler(pid
, policy
, param
);
4803 * sys_sched_setparam - set/change the RT priority of a thread
4804 * @pid: the pid in question.
4805 * @param: structure containing the new RT priority.
4807 SYSCALL_DEFINE2(sched_setparam
, pid_t
, pid
, struct sched_param __user
*, param
)
4809 return do_sched_setscheduler(pid
, -1, param
);
4813 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
4814 * @pid: the pid in question.
4816 SYSCALL_DEFINE1(sched_getscheduler
, pid_t
, pid
)
4818 struct task_struct
*p
;
4826 p
= find_process_by_pid(pid
);
4828 retval
= security_task_getscheduler(p
);
4831 | (p
->sched_reset_on_fork
? SCHED_RESET_ON_FORK
: 0);
4838 * sys_sched_getparam - get the RT priority of a thread
4839 * @pid: the pid in question.
4840 * @param: structure containing the RT priority.
4842 SYSCALL_DEFINE2(sched_getparam
, pid_t
, pid
, struct sched_param __user
*, param
)
4844 struct sched_param lp
;
4845 struct task_struct
*p
;
4848 if (!param
|| pid
< 0)
4852 p
= find_process_by_pid(pid
);
4857 retval
= security_task_getscheduler(p
);
4861 lp
.sched_priority
= p
->rt_priority
;
4865 * This one might sleep, we cannot do it with a spinlock held ...
4867 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
4876 long sched_setaffinity(pid_t pid
, const struct cpumask
*in_mask
)
4878 cpumask_var_t cpus_allowed
, new_mask
;
4879 struct task_struct
*p
;
4885 p
= find_process_by_pid(pid
);
4892 /* Prevent p going away */
4896 if (!alloc_cpumask_var(&cpus_allowed
, GFP_KERNEL
)) {
4900 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
)) {
4902 goto out_free_cpus_allowed
;
4905 if (!check_same_owner(p
) && !capable(CAP_SYS_NICE
))
4908 retval
= security_task_setscheduler(p
);
4912 cpuset_cpus_allowed(p
, cpus_allowed
);
4913 cpumask_and(new_mask
, in_mask
, cpus_allowed
);
4915 retval
= set_cpus_allowed_ptr(p
, new_mask
);
4918 cpuset_cpus_allowed(p
, cpus_allowed
);
4919 if (!cpumask_subset(new_mask
, cpus_allowed
)) {
4921 * We must have raced with a concurrent cpuset
4922 * update. Just reset the cpus_allowed to the
4923 * cpuset's cpus_allowed
4925 cpumask_copy(new_mask
, cpus_allowed
);
4930 free_cpumask_var(new_mask
);
4931 out_free_cpus_allowed
:
4932 free_cpumask_var(cpus_allowed
);
4939 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
4940 struct cpumask
*new_mask
)
4942 if (len
< cpumask_size())
4943 cpumask_clear(new_mask
);
4944 else if (len
> cpumask_size())
4945 len
= cpumask_size();
4947 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
4951 * sys_sched_setaffinity - set the cpu affinity of a process
4952 * @pid: pid of the process
4953 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4954 * @user_mask_ptr: user-space pointer to the new cpu mask
4956 SYSCALL_DEFINE3(sched_setaffinity
, pid_t
, pid
, unsigned int, len
,
4957 unsigned long __user
*, user_mask_ptr
)
4959 cpumask_var_t new_mask
;
4962 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
4965 retval
= get_user_cpu_mask(user_mask_ptr
, len
, new_mask
);
4967 retval
= sched_setaffinity(pid
, new_mask
);
4968 free_cpumask_var(new_mask
);
4972 long sched_getaffinity(pid_t pid
, struct cpumask
*mask
)
4974 struct task_struct
*p
;
4975 unsigned long flags
;
4983 p
= find_process_by_pid(pid
);
4987 retval
= security_task_getscheduler(p
);
4991 rq
= task_rq_lock(p
, &flags
);
4992 cpumask_and(mask
, &p
->cpus_allowed
, cpu_online_mask
);
4993 task_rq_unlock(rq
, &flags
);
5003 * sys_sched_getaffinity - get the cpu affinity of a process
5004 * @pid: pid of the process
5005 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5006 * @user_mask_ptr: user-space pointer to hold the current cpu mask
5008 SYSCALL_DEFINE3(sched_getaffinity
, pid_t
, pid
, unsigned int, len
,
5009 unsigned long __user
*, user_mask_ptr
)
5014 if ((len
* BITS_PER_BYTE
) < nr_cpu_ids
)
5016 if (len
& (sizeof(unsigned long)-1))
5019 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
5022 ret
= sched_getaffinity(pid
, mask
);
5024 size_t retlen
= min_t(size_t, len
, cpumask_size());
5026 if (copy_to_user(user_mask_ptr
, mask
, retlen
))
5031 free_cpumask_var(mask
);
5037 * sys_sched_yield - yield the current processor to other threads.
5039 * This function yields the current CPU to other tasks. If there are no
5040 * other threads running on this CPU then this function will return.
5042 SYSCALL_DEFINE0(sched_yield
)
5044 struct rq
*rq
= this_rq_lock();
5046 schedstat_inc(rq
, yld_count
);
5047 current
->sched_class
->yield_task(rq
);
5050 * Since we are going to call schedule() anyway, there's
5051 * no need to preempt or enable interrupts:
5053 __release(rq
->lock
);
5054 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
5055 do_raw_spin_unlock(&rq
->lock
);
5056 preempt_enable_no_resched();
5063 static inline int should_resched(void)
5065 return need_resched() && !(preempt_count() & PREEMPT_ACTIVE
);
5068 static void __cond_resched(void)
5070 add_preempt_count(PREEMPT_ACTIVE
);
5072 sub_preempt_count(PREEMPT_ACTIVE
);
5075 int __sched
_cond_resched(void)
5077 if (should_resched()) {
5083 EXPORT_SYMBOL(_cond_resched
);
5086 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
5087 * call schedule, and on return reacquire the lock.
5089 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
5090 * operations here to prevent schedule() from being called twice (once via
5091 * spin_unlock(), once by hand).
5093 int __cond_resched_lock(spinlock_t
*lock
)
5095 int resched
= should_resched();
5098 lockdep_assert_held(lock
);
5100 if (spin_needbreak(lock
) || resched
) {
5111 EXPORT_SYMBOL(__cond_resched_lock
);
5113 int __sched
__cond_resched_softirq(void)
5115 BUG_ON(!in_softirq());
5117 if (should_resched()) {
5125 EXPORT_SYMBOL(__cond_resched_softirq
);
5128 * yield - yield the current processor to other threads.
5130 * This is a shortcut for kernel-space yielding - it marks the
5131 * thread runnable and calls sys_sched_yield().
5133 void __sched
yield(void)
5135 set_current_state(TASK_RUNNING
);
5138 EXPORT_SYMBOL(yield
);
5141 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
5142 * that process accounting knows that this is a task in IO wait state.
5144 void __sched
io_schedule(void)
5146 struct rq
*rq
= raw_rq();
5148 delayacct_blkio_start();
5149 atomic_inc(&rq
->nr_iowait
);
5150 current
->in_iowait
= 1;
5152 current
->in_iowait
= 0;
5153 atomic_dec(&rq
->nr_iowait
);
5154 delayacct_blkio_end();
5156 EXPORT_SYMBOL(io_schedule
);
5158 long __sched
io_schedule_timeout(long timeout
)
5160 struct rq
*rq
= raw_rq();
5163 delayacct_blkio_start();
5164 atomic_inc(&rq
->nr_iowait
);
5165 current
->in_iowait
= 1;
5166 ret
= schedule_timeout(timeout
);
5167 current
->in_iowait
= 0;
5168 atomic_dec(&rq
->nr_iowait
);
5169 delayacct_blkio_end();
5174 * sys_sched_get_priority_max - return maximum RT priority.
5175 * @policy: scheduling class.
5177 * this syscall returns the maximum rt_priority that can be used
5178 * by a given scheduling class.
5180 SYSCALL_DEFINE1(sched_get_priority_max
, int, policy
)
5187 ret
= MAX_USER_RT_PRIO
-1;
5199 * sys_sched_get_priority_min - return minimum RT priority.
5200 * @policy: scheduling class.
5202 * this syscall returns the minimum rt_priority that can be used
5203 * by a given scheduling class.
5205 SYSCALL_DEFINE1(sched_get_priority_min
, int, policy
)
5223 * sys_sched_rr_get_interval - return the default timeslice of a process.
5224 * @pid: pid of the process.
5225 * @interval: userspace pointer to the timeslice value.
5227 * this syscall writes the default timeslice value of a given process
5228 * into the user-space timespec buffer. A value of '0' means infinity.
5230 SYSCALL_DEFINE2(sched_rr_get_interval
, pid_t
, pid
,
5231 struct timespec __user
*, interval
)
5233 struct task_struct
*p
;
5234 unsigned int time_slice
;
5235 unsigned long flags
;
5245 p
= find_process_by_pid(pid
);
5249 retval
= security_task_getscheduler(p
);
5253 rq
= task_rq_lock(p
, &flags
);
5254 time_slice
= p
->sched_class
->get_rr_interval(rq
, p
);
5255 task_rq_unlock(rq
, &flags
);
5258 jiffies_to_timespec(time_slice
, &t
);
5259 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
5267 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
5269 void sched_show_task(struct task_struct
*p
)
5271 unsigned long free
= 0;
5274 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
5275 printk(KERN_INFO
"%-15.15s %c", p
->comm
,
5276 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
5277 #if BITS_PER_LONG == 32
5278 if (state
== TASK_RUNNING
)
5279 printk(KERN_CONT
" running ");
5281 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
5283 if (state
== TASK_RUNNING
)
5284 printk(KERN_CONT
" running task ");
5286 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
5288 #ifdef CONFIG_DEBUG_STACK_USAGE
5289 free
= stack_not_used(p
);
5291 printk(KERN_CONT
"%5lu %5d %6d 0x%08lx\n", free
,
5292 task_pid_nr(p
), task_pid_nr(p
->real_parent
),
5293 (unsigned long)task_thread_info(p
)->flags
);
5295 show_stack(p
, NULL
);
5298 void show_state_filter(unsigned long state_filter
)
5300 struct task_struct
*g
, *p
;
5302 #if BITS_PER_LONG == 32
5304 " task PC stack pid father\n");
5307 " task PC stack pid father\n");
5309 read_lock(&tasklist_lock
);
5310 do_each_thread(g
, p
) {
5312 * reset the NMI-timeout, listing all files on a slow
5313 * console might take alot of time:
5315 touch_nmi_watchdog();
5316 if (!state_filter
|| (p
->state
& state_filter
))
5318 } while_each_thread(g
, p
);
5320 touch_all_softlockup_watchdogs();
5322 #ifdef CONFIG_SCHED_DEBUG
5323 sysrq_sched_debug_show();
5325 read_unlock(&tasklist_lock
);
5327 * Only show locks if all tasks are dumped:
5330 debug_show_all_locks();
5333 void __cpuinit
init_idle_bootup_task(struct task_struct
*idle
)
5335 idle
->sched_class
= &idle_sched_class
;
5339 * init_idle - set up an idle thread for a given CPU
5340 * @idle: task in question
5341 * @cpu: cpu the idle task belongs to
5343 * NOTE: this function does not set the idle thread's NEED_RESCHED
5344 * flag, to make booting more robust.
5346 void __cpuinit
init_idle(struct task_struct
*idle
, int cpu
)
5348 struct rq
*rq
= cpu_rq(cpu
);
5349 unsigned long flags
;
5351 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5354 idle
->state
= TASK_RUNNING
;
5355 idle
->se
.exec_start
= sched_clock();
5357 cpumask_copy(&idle
->cpus_allowed
, cpumask_of(cpu
));
5359 * We're having a chicken and egg problem, even though we are
5360 * holding rq->lock, the cpu isn't yet set to this cpu so the
5361 * lockdep check in task_group() will fail.
5363 * Similar case to sched_fork(). / Alternatively we could
5364 * use task_rq_lock() here and obtain the other rq->lock.
5369 __set_task_cpu(idle
, cpu
);
5372 rq
->curr
= rq
->idle
= idle
;
5373 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
5376 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5378 /* Set the preempt count _outside_ the spinlocks! */
5379 #if defined(CONFIG_PREEMPT)
5380 task_thread_info(idle
)->preempt_count
= (idle
->lock_depth
>= 0);
5382 task_thread_info(idle
)->preempt_count
= 0;
5385 * The idle tasks have their own, simple scheduling class:
5387 idle
->sched_class
= &idle_sched_class
;
5388 ftrace_graph_init_task(idle
);
5392 * In a system that switches off the HZ timer nohz_cpu_mask
5393 * indicates which cpus entered this state. This is used
5394 * in the rcu update to wait only for active cpus. For system
5395 * which do not switch off the HZ timer nohz_cpu_mask should
5396 * always be CPU_BITS_NONE.
5398 cpumask_var_t nohz_cpu_mask
;
5401 * Increase the granularity value when there are more CPUs,
5402 * because with more CPUs the 'effective latency' as visible
5403 * to users decreases. But the relationship is not linear,
5404 * so pick a second-best guess by going with the log2 of the
5407 * This idea comes from the SD scheduler of Con Kolivas:
5409 static int get_update_sysctl_factor(void)
5411 unsigned int cpus
= min_t(int, num_online_cpus(), 8);
5412 unsigned int factor
;
5414 switch (sysctl_sched_tunable_scaling
) {
5415 case SCHED_TUNABLESCALING_NONE
:
5418 case SCHED_TUNABLESCALING_LINEAR
:
5421 case SCHED_TUNABLESCALING_LOG
:
5423 factor
= 1 + ilog2(cpus
);
5430 static void update_sysctl(void)
5432 unsigned int factor
= get_update_sysctl_factor();
5434 #define SET_SYSCTL(name) \
5435 (sysctl_##name = (factor) * normalized_sysctl_##name)
5436 SET_SYSCTL(sched_min_granularity
);
5437 SET_SYSCTL(sched_latency
);
5438 SET_SYSCTL(sched_wakeup_granularity
);
5442 static inline void sched_init_granularity(void)
5449 * This is how migration works:
5451 * 1) we invoke migration_cpu_stop() on the target CPU using
5453 * 2) stopper starts to run (implicitly forcing the migrated thread
5455 * 3) it checks whether the migrated task is still in the wrong runqueue.
5456 * 4) if it's in the wrong runqueue then the migration thread removes
5457 * it and puts it into the right queue.
5458 * 5) stopper completes and stop_one_cpu() returns and the migration
5463 * Change a given task's CPU affinity. Migrate the thread to a
5464 * proper CPU and schedule it away if the CPU it's executing on
5465 * is removed from the allowed bitmask.
5467 * NOTE: the caller must have a valid reference to the task, the
5468 * task must not exit() & deallocate itself prematurely. The
5469 * call is not atomic; no spinlocks may be held.
5471 int set_cpus_allowed_ptr(struct task_struct
*p
, const struct cpumask
*new_mask
)
5473 unsigned long flags
;
5475 unsigned int dest_cpu
;
5479 * Serialize against TASK_WAKING so that ttwu() and wunt() can
5480 * drop the rq->lock and still rely on ->cpus_allowed.
5483 while (task_is_waking(p
))
5485 rq
= task_rq_lock(p
, &flags
);
5486 if (task_is_waking(p
)) {
5487 task_rq_unlock(rq
, &flags
);
5491 if (!cpumask_intersects(new_mask
, cpu_active_mask
)) {
5496 if (unlikely((p
->flags
& PF_THREAD_BOUND
) && p
!= current
&&
5497 !cpumask_equal(&p
->cpus_allowed
, new_mask
))) {
5502 if (p
->sched_class
->set_cpus_allowed
)
5503 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
5505 cpumask_copy(&p
->cpus_allowed
, new_mask
);
5506 p
->rt
.nr_cpus_allowed
= cpumask_weight(new_mask
);
5509 /* Can the task run on the task's current CPU? If so, we're done */
5510 if (cpumask_test_cpu(task_cpu(p
), new_mask
))
5513 dest_cpu
= cpumask_any_and(cpu_active_mask
, new_mask
);
5514 if (migrate_task(p
, rq
)) {
5515 struct migration_arg arg
= { p
, dest_cpu
};
5516 /* Need help from migration thread: drop lock and wait. */
5517 task_rq_unlock(rq
, &flags
);
5518 stop_one_cpu(cpu_of(rq
), migration_cpu_stop
, &arg
);
5519 tlb_migrate_finish(p
->mm
);
5523 task_rq_unlock(rq
, &flags
);
5527 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
5530 * Move (not current) task off this cpu, onto dest cpu. We're doing
5531 * this because either it can't run here any more (set_cpus_allowed()
5532 * away from this CPU, or CPU going down), or because we're
5533 * attempting to rebalance this task on exec (sched_exec).
5535 * So we race with normal scheduler movements, but that's OK, as long
5536 * as the task is no longer on this CPU.
5538 * Returns non-zero if task was successfully migrated.
5540 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
5542 struct rq
*rq_dest
, *rq_src
;
5545 if (unlikely(!cpu_active(dest_cpu
)))
5548 rq_src
= cpu_rq(src_cpu
);
5549 rq_dest
= cpu_rq(dest_cpu
);
5551 double_rq_lock(rq_src
, rq_dest
);
5552 /* Already moved. */
5553 if (task_cpu(p
) != src_cpu
)
5555 /* Affinity changed (again). */
5556 if (!cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
5560 * If we're not on a rq, the next wake-up will ensure we're
5564 deactivate_task(rq_src
, p
, 0);
5565 set_task_cpu(p
, dest_cpu
);
5566 activate_task(rq_dest
, p
, 0);
5567 check_preempt_curr(rq_dest
, p
, 0);
5572 double_rq_unlock(rq_src
, rq_dest
);
5577 * migration_cpu_stop - this will be executed by a highprio stopper thread
5578 * and performs thread migration by bumping thread off CPU then
5579 * 'pushing' onto another runqueue.
5581 static int migration_cpu_stop(void *data
)
5583 struct migration_arg
*arg
= data
;
5586 * The original target cpu might have gone down and we might
5587 * be on another cpu but it doesn't matter.
5589 local_irq_disable();
5590 __migrate_task(arg
->task
, raw_smp_processor_id(), arg
->dest_cpu
);
5595 #ifdef CONFIG_HOTPLUG_CPU
5598 * Ensures that the idle task is using init_mm right before its cpu goes
5601 void idle_task_exit(void)
5603 struct mm_struct
*mm
= current
->active_mm
;
5605 BUG_ON(cpu_online(smp_processor_id()));
5608 switch_mm(mm
, &init_mm
, current
);
5613 * While a dead CPU has no uninterruptible tasks queued at this point,
5614 * it might still have a nonzero ->nr_uninterruptible counter, because
5615 * for performance reasons the counter is not stricly tracking tasks to
5616 * their home CPUs. So we just add the counter to another CPU's counter,
5617 * to keep the global sum constant after CPU-down:
5619 static void migrate_nr_uninterruptible(struct rq
*rq_src
)
5621 struct rq
*rq_dest
= cpu_rq(cpumask_any(cpu_active_mask
));
5623 rq_dest
->nr_uninterruptible
+= rq_src
->nr_uninterruptible
;
5624 rq_src
->nr_uninterruptible
= 0;
5628 * remove the tasks which were accounted by rq from calc_load_tasks.
5630 static void calc_global_load_remove(struct rq
*rq
)
5632 atomic_long_sub(rq
->calc_load_active
, &calc_load_tasks
);
5633 rq
->calc_load_active
= 0;
5637 * Migrate all tasks from the rq, sleeping tasks will be migrated by
5638 * try_to_wake_up()->select_task_rq().
5640 * Called with rq->lock held even though we'er in stop_machine() and
5641 * there's no concurrency possible, we hold the required locks anyway
5642 * because of lock validation efforts.
5644 static void migrate_tasks(unsigned int dead_cpu
)
5646 struct rq
*rq
= cpu_rq(dead_cpu
);
5647 struct task_struct
*next
, *stop
= rq
->stop
;
5651 * Fudge the rq selection such that the below task selection loop
5652 * doesn't get stuck on the currently eligible stop task.
5654 * We're currently inside stop_machine() and the rq is either stuck
5655 * in the stop_machine_cpu_stop() loop, or we're executing this code,
5656 * either way we should never end up calling schedule() until we're
5663 * There's this thread running, bail when that's the only
5666 if (rq
->nr_running
== 1)
5669 next
= pick_next_task(rq
);
5671 next
->sched_class
->put_prev_task(rq
, next
);
5673 /* Find suitable destination for @next, with force if needed. */
5674 dest_cpu
= select_fallback_rq(dead_cpu
, next
);
5675 raw_spin_unlock(&rq
->lock
);
5677 __migrate_task(next
, dead_cpu
, dest_cpu
);
5679 raw_spin_lock(&rq
->lock
);
5685 #endif /* CONFIG_HOTPLUG_CPU */
5687 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
5689 static struct ctl_table sd_ctl_dir
[] = {
5691 .procname
= "sched_domain",
5697 static struct ctl_table sd_ctl_root
[] = {
5699 .procname
= "kernel",
5701 .child
= sd_ctl_dir
,
5706 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
5708 struct ctl_table
*entry
=
5709 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
5714 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
5716 struct ctl_table
*entry
;
5719 * In the intermediate directories, both the child directory and
5720 * procname are dynamically allocated and could fail but the mode
5721 * will always be set. In the lowest directory the names are
5722 * static strings and all have proc handlers.
5724 for (entry
= *tablep
; entry
->mode
; entry
++) {
5726 sd_free_ctl_entry(&entry
->child
);
5727 if (entry
->proc_handler
== NULL
)
5728 kfree(entry
->procname
);
5736 set_table_entry(struct ctl_table
*entry
,
5737 const char *procname
, void *data
, int maxlen
,
5738 mode_t mode
, proc_handler
*proc_handler
)
5740 entry
->procname
= procname
;
5742 entry
->maxlen
= maxlen
;
5744 entry
->proc_handler
= proc_handler
;
5747 static struct ctl_table
*
5748 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
5750 struct ctl_table
*table
= sd_alloc_ctl_entry(13);
5755 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
5756 sizeof(long), 0644, proc_doulongvec_minmax
);
5757 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
5758 sizeof(long), 0644, proc_doulongvec_minmax
);
5759 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
5760 sizeof(int), 0644, proc_dointvec_minmax
);
5761 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
5762 sizeof(int), 0644, proc_dointvec_minmax
);
5763 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
5764 sizeof(int), 0644, proc_dointvec_minmax
);
5765 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
5766 sizeof(int), 0644, proc_dointvec_minmax
);
5767 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
5768 sizeof(int), 0644, proc_dointvec_minmax
);
5769 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
5770 sizeof(int), 0644, proc_dointvec_minmax
);
5771 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
5772 sizeof(int), 0644, proc_dointvec_minmax
);
5773 set_table_entry(&table
[9], "cache_nice_tries",
5774 &sd
->cache_nice_tries
,
5775 sizeof(int), 0644, proc_dointvec_minmax
);
5776 set_table_entry(&table
[10], "flags", &sd
->flags
,
5777 sizeof(int), 0644, proc_dointvec_minmax
);
5778 set_table_entry(&table
[11], "name", sd
->name
,
5779 CORENAME_MAX_SIZE
, 0444, proc_dostring
);
5780 /* &table[12] is terminator */
5785 static ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
5787 struct ctl_table
*entry
, *table
;
5788 struct sched_domain
*sd
;
5789 int domain_num
= 0, i
;
5792 for_each_domain(cpu
, sd
)
5794 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
5799 for_each_domain(cpu
, sd
) {
5800 snprintf(buf
, 32, "domain%d", i
);
5801 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5803 entry
->child
= sd_alloc_ctl_domain_table(sd
);
5810 static struct ctl_table_header
*sd_sysctl_header
;
5811 static void register_sched_domain_sysctl(void)
5813 int i
, cpu_num
= num_possible_cpus();
5814 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
5817 WARN_ON(sd_ctl_dir
[0].child
);
5818 sd_ctl_dir
[0].child
= entry
;
5823 for_each_possible_cpu(i
) {
5824 snprintf(buf
, 32, "cpu%d", i
);
5825 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5827 entry
->child
= sd_alloc_ctl_cpu_table(i
);
5831 WARN_ON(sd_sysctl_header
);
5832 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
5835 /* may be called multiple times per register */
5836 static void unregister_sched_domain_sysctl(void)
5838 if (sd_sysctl_header
)
5839 unregister_sysctl_table(sd_sysctl_header
);
5840 sd_sysctl_header
= NULL
;
5841 if (sd_ctl_dir
[0].child
)
5842 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
5845 static void register_sched_domain_sysctl(void)
5848 static void unregister_sched_domain_sysctl(void)
5853 static void set_rq_online(struct rq
*rq
)
5856 const struct sched_class
*class;
5858 cpumask_set_cpu(rq
->cpu
, rq
->rd
->online
);
5861 for_each_class(class) {
5862 if (class->rq_online
)
5863 class->rq_online(rq
);
5868 static void set_rq_offline(struct rq
*rq
)
5871 const struct sched_class
*class;
5873 for_each_class(class) {
5874 if (class->rq_offline
)
5875 class->rq_offline(rq
);
5878 cpumask_clear_cpu(rq
->cpu
, rq
->rd
->online
);
5884 * migration_call - callback that gets triggered when a CPU is added.
5885 * Here we can start up the necessary migration thread for the new CPU.
5887 static int __cpuinit
5888 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
5890 int cpu
= (long)hcpu
;
5891 unsigned long flags
;
5892 struct rq
*rq
= cpu_rq(cpu
);
5894 switch (action
& ~CPU_TASKS_FROZEN
) {
5896 case CPU_UP_PREPARE
:
5897 rq
->calc_load_update
= calc_load_update
;
5901 /* Update our root-domain */
5902 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5904 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
5908 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5911 #ifdef CONFIG_HOTPLUG_CPU
5913 /* Update our root-domain */
5914 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5916 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
5920 BUG_ON(rq
->nr_running
!= 1); /* the migration thread */
5921 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5923 migrate_nr_uninterruptible(rq
);
5924 calc_global_load_remove(rq
);
5932 * Register at high priority so that task migration (migrate_all_tasks)
5933 * happens before everything else. This has to be lower priority than
5934 * the notifier in the perf_event subsystem, though.
5936 static struct notifier_block __cpuinitdata migration_notifier
= {
5937 .notifier_call
= migration_call
,
5938 .priority
= CPU_PRI_MIGRATION
,
5941 static int __cpuinit
sched_cpu_active(struct notifier_block
*nfb
,
5942 unsigned long action
, void *hcpu
)
5944 switch (action
& ~CPU_TASKS_FROZEN
) {
5946 case CPU_DOWN_FAILED
:
5947 set_cpu_active((long)hcpu
, true);
5954 static int __cpuinit
sched_cpu_inactive(struct notifier_block
*nfb
,
5955 unsigned long action
, void *hcpu
)
5957 switch (action
& ~CPU_TASKS_FROZEN
) {
5958 case CPU_DOWN_PREPARE
:
5959 set_cpu_active((long)hcpu
, false);
5966 static int __init
migration_init(void)
5968 void *cpu
= (void *)(long)smp_processor_id();
5971 /* Initialize migration for the boot CPU */
5972 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
5973 BUG_ON(err
== NOTIFY_BAD
);
5974 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
5975 register_cpu_notifier(&migration_notifier
);
5977 /* Register cpu active notifiers */
5978 cpu_notifier(sched_cpu_active
, CPU_PRI_SCHED_ACTIVE
);
5979 cpu_notifier(sched_cpu_inactive
, CPU_PRI_SCHED_INACTIVE
);
5983 early_initcall(migration_init
);
5988 #ifdef CONFIG_SCHED_DEBUG
5990 static __read_mostly
int sched_domain_debug_enabled
;
5992 static int __init
sched_domain_debug_setup(char *str
)
5994 sched_domain_debug_enabled
= 1;
5998 early_param("sched_debug", sched_domain_debug_setup
);
6000 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
6001 struct cpumask
*groupmask
)
6003 struct sched_group
*group
= sd
->groups
;
6006 cpulist_scnprintf(str
, sizeof(str
), sched_domain_span(sd
));
6007 cpumask_clear(groupmask
);
6009 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
6011 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
6012 printk("does not load-balance\n");
6014 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
6019 printk(KERN_CONT
"span %s level %s\n", str
, sd
->name
);
6021 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
6022 printk(KERN_ERR
"ERROR: domain->span does not contain "
6025 if (!cpumask_test_cpu(cpu
, sched_group_cpus(group
))) {
6026 printk(KERN_ERR
"ERROR: domain->groups does not contain"
6030 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
6034 printk(KERN_ERR
"ERROR: group is NULL\n");
6038 if (!group
->cpu_power
) {
6039 printk(KERN_CONT
"\n");
6040 printk(KERN_ERR
"ERROR: domain->cpu_power not "
6045 if (!cpumask_weight(sched_group_cpus(group
))) {
6046 printk(KERN_CONT
"\n");
6047 printk(KERN_ERR
"ERROR: empty group\n");
6051 if (cpumask_intersects(groupmask
, sched_group_cpus(group
))) {
6052 printk(KERN_CONT
"\n");
6053 printk(KERN_ERR
"ERROR: repeated CPUs\n");
6057 cpumask_or(groupmask
, groupmask
, sched_group_cpus(group
));
6059 cpulist_scnprintf(str
, sizeof(str
), sched_group_cpus(group
));
6061 printk(KERN_CONT
" %s", str
);
6062 if (group
->cpu_power
!= SCHED_LOAD_SCALE
) {
6063 printk(KERN_CONT
" (cpu_power = %d)",
6067 group
= group
->next
;
6068 } while (group
!= sd
->groups
);
6069 printk(KERN_CONT
"\n");
6071 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
6072 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
6075 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
6076 printk(KERN_ERR
"ERROR: parent span is not a superset "
6077 "of domain->span\n");
6081 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
6083 cpumask_var_t groupmask
;
6086 if (!sched_domain_debug_enabled
)
6090 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
6094 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
6096 if (!alloc_cpumask_var(&groupmask
, GFP_KERNEL
)) {
6097 printk(KERN_DEBUG
"Cannot load-balance (out of memory)\n");
6102 if (sched_domain_debug_one(sd
, cpu
, level
, groupmask
))
6109 free_cpumask_var(groupmask
);
6111 #else /* !CONFIG_SCHED_DEBUG */
6112 # define sched_domain_debug(sd, cpu) do { } while (0)
6113 #endif /* CONFIG_SCHED_DEBUG */
6115 static int sd_degenerate(struct sched_domain
*sd
)
6117 if (cpumask_weight(sched_domain_span(sd
)) == 1)
6120 /* Following flags need at least 2 groups */
6121 if (sd
->flags
& (SD_LOAD_BALANCE
|
6122 SD_BALANCE_NEWIDLE
|
6126 SD_SHARE_PKG_RESOURCES
)) {
6127 if (sd
->groups
!= sd
->groups
->next
)
6131 /* Following flags don't use groups */
6132 if (sd
->flags
& (SD_WAKE_AFFINE
))
6139 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
6141 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
6143 if (sd_degenerate(parent
))
6146 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
6149 /* Flags needing groups don't count if only 1 group in parent */
6150 if (parent
->groups
== parent
->groups
->next
) {
6151 pflags
&= ~(SD_LOAD_BALANCE
|
6152 SD_BALANCE_NEWIDLE
|
6156 SD_SHARE_PKG_RESOURCES
);
6157 if (nr_node_ids
== 1)
6158 pflags
&= ~SD_SERIALIZE
;
6160 if (~cflags
& pflags
)
6166 static void free_rootdomain(struct root_domain
*rd
)
6168 synchronize_sched();
6170 cpupri_cleanup(&rd
->cpupri
);
6172 free_cpumask_var(rd
->rto_mask
);
6173 free_cpumask_var(rd
->online
);
6174 free_cpumask_var(rd
->span
);
6178 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
6180 struct root_domain
*old_rd
= NULL
;
6181 unsigned long flags
;
6183 raw_spin_lock_irqsave(&rq
->lock
, flags
);
6188 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
6191 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
6194 * If we dont want to free the old_rt yet then
6195 * set old_rd to NULL to skip the freeing later
6198 if (!atomic_dec_and_test(&old_rd
->refcount
))
6202 atomic_inc(&rd
->refcount
);
6205 cpumask_set_cpu(rq
->cpu
, rd
->span
);
6206 if (cpumask_test_cpu(rq
->cpu
, cpu_active_mask
))
6209 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
6212 free_rootdomain(old_rd
);
6215 static int init_rootdomain(struct root_domain
*rd
)
6217 memset(rd
, 0, sizeof(*rd
));
6219 if (!alloc_cpumask_var(&rd
->span
, GFP_KERNEL
))
6221 if (!alloc_cpumask_var(&rd
->online
, GFP_KERNEL
))
6223 if (!alloc_cpumask_var(&rd
->rto_mask
, GFP_KERNEL
))
6226 if (cpupri_init(&rd
->cpupri
) != 0)
6231 free_cpumask_var(rd
->rto_mask
);
6233 free_cpumask_var(rd
->online
);
6235 free_cpumask_var(rd
->span
);
6240 static void init_defrootdomain(void)
6242 init_rootdomain(&def_root_domain
);
6244 atomic_set(&def_root_domain
.refcount
, 1);
6247 static struct root_domain
*alloc_rootdomain(void)
6249 struct root_domain
*rd
;
6251 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
6255 if (init_rootdomain(rd
) != 0) {
6264 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
6265 * hold the hotplug lock.
6268 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
6270 struct rq
*rq
= cpu_rq(cpu
);
6271 struct sched_domain
*tmp
;
6273 for (tmp
= sd
; tmp
; tmp
= tmp
->parent
)
6274 tmp
->span_weight
= cpumask_weight(sched_domain_span(tmp
));
6276 /* Remove the sched domains which do not contribute to scheduling. */
6277 for (tmp
= sd
; tmp
; ) {
6278 struct sched_domain
*parent
= tmp
->parent
;
6282 if (sd_parent_degenerate(tmp
, parent
)) {
6283 tmp
->parent
= parent
->parent
;
6285 parent
->parent
->child
= tmp
;
6290 if (sd
&& sd_degenerate(sd
)) {
6296 sched_domain_debug(sd
, cpu
);
6298 rq_attach_root(rq
, rd
);
6299 rcu_assign_pointer(rq
->sd
, sd
);
6302 /* cpus with isolated domains */
6303 static cpumask_var_t cpu_isolated_map
;
6305 /* Setup the mask of cpus configured for isolated domains */
6306 static int __init
isolated_cpu_setup(char *str
)
6308 alloc_bootmem_cpumask_var(&cpu_isolated_map
);
6309 cpulist_parse(str
, cpu_isolated_map
);
6313 __setup("isolcpus=", isolated_cpu_setup
);
6316 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
6317 * to a function which identifies what group(along with sched group) a CPU
6318 * belongs to. The return value of group_fn must be a >= 0 and < nr_cpu_ids
6319 * (due to the fact that we keep track of groups covered with a struct cpumask).
6321 * init_sched_build_groups will build a circular linked list of the groups
6322 * covered by the given span, and will set each group's ->cpumask correctly,
6323 * and ->cpu_power to 0.
6326 init_sched_build_groups(const struct cpumask
*span
,
6327 const struct cpumask
*cpu_map
,
6328 int (*group_fn
)(int cpu
, const struct cpumask
*cpu_map
,
6329 struct sched_group
**sg
,
6330 struct cpumask
*tmpmask
),
6331 struct cpumask
*covered
, struct cpumask
*tmpmask
)
6333 struct sched_group
*first
= NULL
, *last
= NULL
;
6336 cpumask_clear(covered
);
6338 for_each_cpu(i
, span
) {
6339 struct sched_group
*sg
;
6340 int group
= group_fn(i
, cpu_map
, &sg
, tmpmask
);
6343 if (cpumask_test_cpu(i
, covered
))
6346 cpumask_clear(sched_group_cpus(sg
));
6349 for_each_cpu(j
, span
) {
6350 if (group_fn(j
, cpu_map
, NULL
, tmpmask
) != group
)
6353 cpumask_set_cpu(j
, covered
);
6354 cpumask_set_cpu(j
, sched_group_cpus(sg
));
6365 #define SD_NODES_PER_DOMAIN 16
6370 * find_next_best_node - find the next node to include in a sched_domain
6371 * @node: node whose sched_domain we're building
6372 * @used_nodes: nodes already in the sched_domain
6374 * Find the next node to include in a given scheduling domain. Simply
6375 * finds the closest node not already in the @used_nodes map.
6377 * Should use nodemask_t.
6379 static int find_next_best_node(int node
, nodemask_t
*used_nodes
)
6381 int i
, n
, val
, min_val
, best_node
= 0;
6385 for (i
= 0; i
< nr_node_ids
; i
++) {
6386 /* Start at @node */
6387 n
= (node
+ i
) % nr_node_ids
;
6389 if (!nr_cpus_node(n
))
6392 /* Skip already used nodes */
6393 if (node_isset(n
, *used_nodes
))
6396 /* Simple min distance search */
6397 val
= node_distance(node
, n
);
6399 if (val
< min_val
) {
6405 node_set(best_node
, *used_nodes
);
6410 * sched_domain_node_span - get a cpumask for a node's sched_domain
6411 * @node: node whose cpumask we're constructing
6412 * @span: resulting cpumask
6414 * Given a node, construct a good cpumask for its sched_domain to span. It
6415 * should be one that prevents unnecessary balancing, but also spreads tasks
6418 static void sched_domain_node_span(int node
, struct cpumask
*span
)
6420 nodemask_t used_nodes
;
6423 cpumask_clear(span
);
6424 nodes_clear(used_nodes
);
6426 cpumask_or(span
, span
, cpumask_of_node(node
));
6427 node_set(node
, used_nodes
);
6429 for (i
= 1; i
< SD_NODES_PER_DOMAIN
; i
++) {
6430 int next_node
= find_next_best_node(node
, &used_nodes
);
6432 cpumask_or(span
, span
, cpumask_of_node(next_node
));
6435 #endif /* CONFIG_NUMA */
6437 int sched_smt_power_savings
= 0, sched_mc_power_savings
= 0;
6440 * The cpus mask in sched_group and sched_domain hangs off the end.
6442 * ( See the the comments in include/linux/sched.h:struct sched_group
6443 * and struct sched_domain. )
6445 struct static_sched_group
{
6446 struct sched_group sg
;
6447 DECLARE_BITMAP(cpus
, CONFIG_NR_CPUS
);
6450 struct static_sched_domain
{
6451 struct sched_domain sd
;
6452 DECLARE_BITMAP(span
, CONFIG_NR_CPUS
);
6458 cpumask_var_t domainspan
;
6459 cpumask_var_t covered
;
6460 cpumask_var_t notcovered
;
6462 cpumask_var_t nodemask
;
6463 cpumask_var_t this_sibling_map
;
6464 cpumask_var_t this_core_map
;
6465 cpumask_var_t this_book_map
;
6466 cpumask_var_t send_covered
;
6467 cpumask_var_t tmpmask
;
6468 struct sched_group
**sched_group_nodes
;
6469 struct root_domain
*rd
;
6473 sa_sched_groups
= 0,
6479 sa_this_sibling_map
,
6481 sa_sched_group_nodes
,
6491 * SMT sched-domains:
6493 #ifdef CONFIG_SCHED_SMT
6494 static DEFINE_PER_CPU(struct static_sched_domain
, cpu_domains
);
6495 static DEFINE_PER_CPU(struct static_sched_group
, sched_groups
);
6498 cpu_to_cpu_group(int cpu
, const struct cpumask
*cpu_map
,
6499 struct sched_group
**sg
, struct cpumask
*unused
)
6502 *sg
= &per_cpu(sched_groups
, cpu
).sg
;
6505 #endif /* CONFIG_SCHED_SMT */
6508 * multi-core sched-domains:
6510 #ifdef CONFIG_SCHED_MC
6511 static DEFINE_PER_CPU(struct static_sched_domain
, core_domains
);
6512 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_core
);
6515 cpu_to_core_group(int cpu
, const struct cpumask
*cpu_map
,
6516 struct sched_group
**sg
, struct cpumask
*mask
)
6519 #ifdef CONFIG_SCHED_SMT
6520 cpumask_and(mask
, topology_thread_cpumask(cpu
), cpu_map
);
6521 group
= cpumask_first(mask
);
6526 *sg
= &per_cpu(sched_group_core
, group
).sg
;
6529 #endif /* CONFIG_SCHED_MC */
6532 * book sched-domains:
6534 #ifdef CONFIG_SCHED_BOOK
6535 static DEFINE_PER_CPU(struct static_sched_domain
, book_domains
);
6536 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_book
);
6539 cpu_to_book_group(int cpu
, const struct cpumask
*cpu_map
,
6540 struct sched_group
**sg
, struct cpumask
*mask
)
6543 #ifdef CONFIG_SCHED_MC
6544 cpumask_and(mask
, cpu_coregroup_mask(cpu
), cpu_map
);
6545 group
= cpumask_first(mask
);
6546 #elif defined(CONFIG_SCHED_SMT)
6547 cpumask_and(mask
, topology_thread_cpumask(cpu
), cpu_map
);
6548 group
= cpumask_first(mask
);
6551 *sg
= &per_cpu(sched_group_book
, group
).sg
;
6554 #endif /* CONFIG_SCHED_BOOK */
6556 static DEFINE_PER_CPU(struct static_sched_domain
, phys_domains
);
6557 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_phys
);
6560 cpu_to_phys_group(int cpu
, const struct cpumask
*cpu_map
,
6561 struct sched_group
**sg
, struct cpumask
*mask
)
6564 #ifdef CONFIG_SCHED_BOOK
6565 cpumask_and(mask
, cpu_book_mask(cpu
), cpu_map
);
6566 group
= cpumask_first(mask
);
6567 #elif defined(CONFIG_SCHED_MC)
6568 cpumask_and(mask
, cpu_coregroup_mask(cpu
), cpu_map
);
6569 group
= cpumask_first(mask
);
6570 #elif defined(CONFIG_SCHED_SMT)
6571 cpumask_and(mask
, topology_thread_cpumask(cpu
), cpu_map
);
6572 group
= cpumask_first(mask
);
6577 *sg
= &per_cpu(sched_group_phys
, group
).sg
;
6583 * The init_sched_build_groups can't handle what we want to do with node
6584 * groups, so roll our own. Now each node has its own list of groups which
6585 * gets dynamically allocated.
6587 static DEFINE_PER_CPU(struct static_sched_domain
, node_domains
);
6588 static struct sched_group
***sched_group_nodes_bycpu
;
6590 static DEFINE_PER_CPU(struct static_sched_domain
, allnodes_domains
);
6591 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_allnodes
);
6593 static int cpu_to_allnodes_group(int cpu
, const struct cpumask
*cpu_map
,
6594 struct sched_group
**sg
,
6595 struct cpumask
*nodemask
)
6599 cpumask_and(nodemask
, cpumask_of_node(cpu_to_node(cpu
)), cpu_map
);
6600 group
= cpumask_first(nodemask
);
6603 *sg
= &per_cpu(sched_group_allnodes
, group
).sg
;
6607 static void init_numa_sched_groups_power(struct sched_group
*group_head
)
6609 struct sched_group
*sg
= group_head
;
6615 for_each_cpu(j
, sched_group_cpus(sg
)) {
6616 struct sched_domain
*sd
;
6618 sd
= &per_cpu(phys_domains
, j
).sd
;
6619 if (j
!= group_first_cpu(sd
->groups
)) {
6621 * Only add "power" once for each
6627 sg
->cpu_power
+= sd
->groups
->cpu_power
;
6630 } while (sg
!= group_head
);
6633 static int build_numa_sched_groups(struct s_data
*d
,
6634 const struct cpumask
*cpu_map
, int num
)
6636 struct sched_domain
*sd
;
6637 struct sched_group
*sg
, *prev
;
6640 cpumask_clear(d
->covered
);
6641 cpumask_and(d
->nodemask
, cpumask_of_node(num
), cpu_map
);
6642 if (cpumask_empty(d
->nodemask
)) {
6643 d
->sched_group_nodes
[num
] = NULL
;
6647 sched_domain_node_span(num
, d
->domainspan
);
6648 cpumask_and(d
->domainspan
, d
->domainspan
, cpu_map
);
6650 sg
= kmalloc_node(sizeof(struct sched_group
) + cpumask_size(),
6653 printk(KERN_WARNING
"Can not alloc domain group for node %d\n",
6657 d
->sched_group_nodes
[num
] = sg
;
6659 for_each_cpu(j
, d
->nodemask
) {
6660 sd
= &per_cpu(node_domains
, j
).sd
;
6665 cpumask_copy(sched_group_cpus(sg
), d
->nodemask
);
6667 cpumask_or(d
->covered
, d
->covered
, d
->nodemask
);
6670 for (j
= 0; j
< nr_node_ids
; j
++) {
6671 n
= (num
+ j
) % nr_node_ids
;
6672 cpumask_complement(d
->notcovered
, d
->covered
);
6673 cpumask_and(d
->tmpmask
, d
->notcovered
, cpu_map
);
6674 cpumask_and(d
->tmpmask
, d
->tmpmask
, d
->domainspan
);
6675 if (cpumask_empty(d
->tmpmask
))
6677 cpumask_and(d
->tmpmask
, d
->tmpmask
, cpumask_of_node(n
));
6678 if (cpumask_empty(d
->tmpmask
))
6680 sg
= kmalloc_node(sizeof(struct sched_group
) + cpumask_size(),
6684 "Can not alloc domain group for node %d\n", j
);
6688 cpumask_copy(sched_group_cpus(sg
), d
->tmpmask
);
6689 sg
->next
= prev
->next
;
6690 cpumask_or(d
->covered
, d
->covered
, d
->tmpmask
);
6697 #endif /* CONFIG_NUMA */
6700 /* Free memory allocated for various sched_group structures */
6701 static void free_sched_groups(const struct cpumask
*cpu_map
,
6702 struct cpumask
*nodemask
)
6706 for_each_cpu(cpu
, cpu_map
) {
6707 struct sched_group
**sched_group_nodes
6708 = sched_group_nodes_bycpu
[cpu
];
6710 if (!sched_group_nodes
)
6713 for (i
= 0; i
< nr_node_ids
; i
++) {
6714 struct sched_group
*oldsg
, *sg
= sched_group_nodes
[i
];
6716 cpumask_and(nodemask
, cpumask_of_node(i
), cpu_map
);
6717 if (cpumask_empty(nodemask
))
6727 if (oldsg
!= sched_group_nodes
[i
])
6730 kfree(sched_group_nodes
);
6731 sched_group_nodes_bycpu
[cpu
] = NULL
;
6734 #else /* !CONFIG_NUMA */
6735 static void free_sched_groups(const struct cpumask
*cpu_map
,
6736 struct cpumask
*nodemask
)
6739 #endif /* CONFIG_NUMA */
6742 * Initialize sched groups cpu_power.
6744 * cpu_power indicates the capacity of sched group, which is used while
6745 * distributing the load between different sched groups in a sched domain.
6746 * Typically cpu_power for all the groups in a sched domain will be same unless
6747 * there are asymmetries in the topology. If there are asymmetries, group
6748 * having more cpu_power will pickup more load compared to the group having
6751 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
6753 struct sched_domain
*child
;
6754 struct sched_group
*group
;
6758 WARN_ON(!sd
|| !sd
->groups
);
6760 if (cpu
!= group_first_cpu(sd
->groups
))
6763 sd
->groups
->group_weight
= cpumask_weight(sched_group_cpus(sd
->groups
));
6767 sd
->groups
->cpu_power
= 0;
6770 power
= SCHED_LOAD_SCALE
;
6771 weight
= cpumask_weight(sched_domain_span(sd
));
6773 * SMT siblings share the power of a single core.
6774 * Usually multiple threads get a better yield out of
6775 * that one core than a single thread would have,
6776 * reflect that in sd->smt_gain.
6778 if ((sd
->flags
& SD_SHARE_CPUPOWER
) && weight
> 1) {
6779 power
*= sd
->smt_gain
;
6781 power
>>= SCHED_LOAD_SHIFT
;
6783 sd
->groups
->cpu_power
+= power
;
6788 * Add cpu_power of each child group to this groups cpu_power.
6790 group
= child
->groups
;
6792 sd
->groups
->cpu_power
+= group
->cpu_power
;
6793 group
= group
->next
;
6794 } while (group
!= child
->groups
);
6798 * Initializers for schedule domains
6799 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
6802 #ifdef CONFIG_SCHED_DEBUG
6803 # define SD_INIT_NAME(sd, type) sd->name = #type
6805 # define SD_INIT_NAME(sd, type) do { } while (0)
6808 #define SD_INIT(sd, type) sd_init_##type(sd)
6810 #define SD_INIT_FUNC(type) \
6811 static noinline void sd_init_##type(struct sched_domain *sd) \
6813 memset(sd, 0, sizeof(*sd)); \
6814 *sd = SD_##type##_INIT; \
6815 sd->level = SD_LV_##type; \
6816 SD_INIT_NAME(sd, type); \
6821 SD_INIT_FUNC(ALLNODES
)
6824 #ifdef CONFIG_SCHED_SMT
6825 SD_INIT_FUNC(SIBLING
)
6827 #ifdef CONFIG_SCHED_MC
6830 #ifdef CONFIG_SCHED_BOOK
6834 static int default_relax_domain_level
= -1;
6836 static int __init
setup_relax_domain_level(char *str
)
6840 val
= simple_strtoul(str
, NULL
, 0);
6841 if (val
< SD_LV_MAX
)
6842 default_relax_domain_level
= val
;
6846 __setup("relax_domain_level=", setup_relax_domain_level
);
6848 static void set_domain_attribute(struct sched_domain
*sd
,
6849 struct sched_domain_attr
*attr
)
6853 if (!attr
|| attr
->relax_domain_level
< 0) {
6854 if (default_relax_domain_level
< 0)
6857 request
= default_relax_domain_level
;
6859 request
= attr
->relax_domain_level
;
6860 if (request
< sd
->level
) {
6861 /* turn off idle balance on this domain */
6862 sd
->flags
&= ~(SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
6864 /* turn on idle balance on this domain */
6865 sd
->flags
|= (SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
6869 static void __free_domain_allocs(struct s_data
*d
, enum s_alloc what
,
6870 const struct cpumask
*cpu_map
)
6873 case sa_sched_groups
:
6874 free_sched_groups(cpu_map
, d
->tmpmask
); /* fall through */
6875 d
->sched_group_nodes
= NULL
;
6877 free_rootdomain(d
->rd
); /* fall through */
6879 free_cpumask_var(d
->tmpmask
); /* fall through */
6880 case sa_send_covered
:
6881 free_cpumask_var(d
->send_covered
); /* fall through */
6882 case sa_this_book_map
:
6883 free_cpumask_var(d
->this_book_map
); /* fall through */
6884 case sa_this_core_map
:
6885 free_cpumask_var(d
->this_core_map
); /* fall through */
6886 case sa_this_sibling_map
:
6887 free_cpumask_var(d
->this_sibling_map
); /* fall through */
6889 free_cpumask_var(d
->nodemask
); /* fall through */
6890 case sa_sched_group_nodes
:
6892 kfree(d
->sched_group_nodes
); /* fall through */
6894 free_cpumask_var(d
->notcovered
); /* fall through */
6896 free_cpumask_var(d
->covered
); /* fall through */
6898 free_cpumask_var(d
->domainspan
); /* fall through */
6905 static enum s_alloc
__visit_domain_allocation_hell(struct s_data
*d
,
6906 const struct cpumask
*cpu_map
)
6909 if (!alloc_cpumask_var(&d
->domainspan
, GFP_KERNEL
))
6911 if (!alloc_cpumask_var(&d
->covered
, GFP_KERNEL
))
6912 return sa_domainspan
;
6913 if (!alloc_cpumask_var(&d
->notcovered
, GFP_KERNEL
))
6915 /* Allocate the per-node list of sched groups */
6916 d
->sched_group_nodes
= kcalloc(nr_node_ids
,
6917 sizeof(struct sched_group
*), GFP_KERNEL
);
6918 if (!d
->sched_group_nodes
) {
6919 printk(KERN_WARNING
"Can not alloc sched group node list\n");
6920 return sa_notcovered
;
6922 sched_group_nodes_bycpu
[cpumask_first(cpu_map
)] = d
->sched_group_nodes
;
6924 if (!alloc_cpumask_var(&d
->nodemask
, GFP_KERNEL
))
6925 return sa_sched_group_nodes
;
6926 if (!alloc_cpumask_var(&d
->this_sibling_map
, GFP_KERNEL
))
6928 if (!alloc_cpumask_var(&d
->this_core_map
, GFP_KERNEL
))
6929 return sa_this_sibling_map
;
6930 if (!alloc_cpumask_var(&d
->this_book_map
, GFP_KERNEL
))
6931 return sa_this_core_map
;
6932 if (!alloc_cpumask_var(&d
->send_covered
, GFP_KERNEL
))
6933 return sa_this_book_map
;
6934 if (!alloc_cpumask_var(&d
->tmpmask
, GFP_KERNEL
))
6935 return sa_send_covered
;
6936 d
->rd
= alloc_rootdomain();
6938 printk(KERN_WARNING
"Cannot alloc root domain\n");
6941 return sa_rootdomain
;
6944 static struct sched_domain
*__build_numa_sched_domains(struct s_data
*d
,
6945 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
, int i
)
6947 struct sched_domain
*sd
= NULL
;
6949 struct sched_domain
*parent
;
6952 if (cpumask_weight(cpu_map
) >
6953 SD_NODES_PER_DOMAIN
* cpumask_weight(d
->nodemask
)) {
6954 sd
= &per_cpu(allnodes_domains
, i
).sd
;
6955 SD_INIT(sd
, ALLNODES
);
6956 set_domain_attribute(sd
, attr
);
6957 cpumask_copy(sched_domain_span(sd
), cpu_map
);
6958 cpu_to_allnodes_group(i
, cpu_map
, &sd
->groups
, d
->tmpmask
);
6963 sd
= &per_cpu(node_domains
, i
).sd
;
6965 set_domain_attribute(sd
, attr
);
6966 sched_domain_node_span(cpu_to_node(i
), sched_domain_span(sd
));
6967 sd
->parent
= parent
;
6970 cpumask_and(sched_domain_span(sd
), sched_domain_span(sd
), cpu_map
);
6975 static struct sched_domain
*__build_cpu_sched_domain(struct s_data
*d
,
6976 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
6977 struct sched_domain
*parent
, int i
)
6979 struct sched_domain
*sd
;
6980 sd
= &per_cpu(phys_domains
, i
).sd
;
6982 set_domain_attribute(sd
, attr
);
6983 cpumask_copy(sched_domain_span(sd
), d
->nodemask
);
6984 sd
->parent
= parent
;
6987 cpu_to_phys_group(i
, cpu_map
, &sd
->groups
, d
->tmpmask
);
6991 static struct sched_domain
*__build_book_sched_domain(struct s_data
*d
,
6992 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
6993 struct sched_domain
*parent
, int i
)
6995 struct sched_domain
*sd
= parent
;
6996 #ifdef CONFIG_SCHED_BOOK
6997 sd
= &per_cpu(book_domains
, i
).sd
;
6999 set_domain_attribute(sd
, attr
);
7000 cpumask_and(sched_domain_span(sd
), cpu_map
, cpu_book_mask(i
));
7001 sd
->parent
= parent
;
7003 cpu_to_book_group(i
, cpu_map
, &sd
->groups
, d
->tmpmask
);
7008 static struct sched_domain
*__build_mc_sched_domain(struct s_data
*d
,
7009 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
7010 struct sched_domain
*parent
, int i
)
7012 struct sched_domain
*sd
= parent
;
7013 #ifdef CONFIG_SCHED_MC
7014 sd
= &per_cpu(core_domains
, i
).sd
;
7016 set_domain_attribute(sd
, attr
);
7017 cpumask_and(sched_domain_span(sd
), cpu_map
, cpu_coregroup_mask(i
));
7018 sd
->parent
= parent
;
7020 cpu_to_core_group(i
, cpu_map
, &sd
->groups
, d
->tmpmask
);
7025 static struct sched_domain
*__build_smt_sched_domain(struct s_data
*d
,
7026 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
7027 struct sched_domain
*parent
, int i
)
7029 struct sched_domain
*sd
= parent
;
7030 #ifdef CONFIG_SCHED_SMT
7031 sd
= &per_cpu(cpu_domains
, i
).sd
;
7032 SD_INIT(sd
, SIBLING
);
7033 set_domain_attribute(sd
, attr
);
7034 cpumask_and(sched_domain_span(sd
), cpu_map
, topology_thread_cpumask(i
));
7035 sd
->parent
= parent
;
7037 cpu_to_cpu_group(i
, cpu_map
, &sd
->groups
, d
->tmpmask
);
7042 static void build_sched_groups(struct s_data
*d
, enum sched_domain_level l
,
7043 const struct cpumask
*cpu_map
, int cpu
)
7046 #ifdef CONFIG_SCHED_SMT
7047 case SD_LV_SIBLING
: /* set up CPU (sibling) groups */
7048 cpumask_and(d
->this_sibling_map
, cpu_map
,
7049 topology_thread_cpumask(cpu
));
7050 if (cpu
== cpumask_first(d
->this_sibling_map
))
7051 init_sched_build_groups(d
->this_sibling_map
, cpu_map
,
7053 d
->send_covered
, d
->tmpmask
);
7056 #ifdef CONFIG_SCHED_MC
7057 case SD_LV_MC
: /* set up multi-core groups */
7058 cpumask_and(d
->this_core_map
, cpu_map
, cpu_coregroup_mask(cpu
));
7059 if (cpu
== cpumask_first(d
->this_core_map
))
7060 init_sched_build_groups(d
->this_core_map
, cpu_map
,
7062 d
->send_covered
, d
->tmpmask
);
7065 #ifdef CONFIG_SCHED_BOOK
7066 case SD_LV_BOOK
: /* set up book groups */
7067 cpumask_and(d
->this_book_map
, cpu_map
, cpu_book_mask(cpu
));
7068 if (cpu
== cpumask_first(d
->this_book_map
))
7069 init_sched_build_groups(d
->this_book_map
, cpu_map
,
7071 d
->send_covered
, d
->tmpmask
);
7074 case SD_LV_CPU
: /* set up physical groups */
7075 cpumask_and(d
->nodemask
, cpumask_of_node(cpu
), cpu_map
);
7076 if (!cpumask_empty(d
->nodemask
))
7077 init_sched_build_groups(d
->nodemask
, cpu_map
,
7079 d
->send_covered
, d
->tmpmask
);
7082 case SD_LV_ALLNODES
:
7083 init_sched_build_groups(cpu_map
, cpu_map
, &cpu_to_allnodes_group
,
7084 d
->send_covered
, d
->tmpmask
);
7093 * Build sched domains for a given set of cpus and attach the sched domains
7094 * to the individual cpus
7096 static int __build_sched_domains(const struct cpumask
*cpu_map
,
7097 struct sched_domain_attr
*attr
)
7099 enum s_alloc alloc_state
= sa_none
;
7101 struct sched_domain
*sd
;
7107 alloc_state
= __visit_domain_allocation_hell(&d
, cpu_map
);
7108 if (alloc_state
!= sa_rootdomain
)
7110 alloc_state
= sa_sched_groups
;
7113 * Set up domains for cpus specified by the cpu_map.
7115 for_each_cpu(i
, cpu_map
) {
7116 cpumask_and(d
.nodemask
, cpumask_of_node(cpu_to_node(i
)),
7119 sd
= __build_numa_sched_domains(&d
, cpu_map
, attr
, i
);
7120 sd
= __build_cpu_sched_domain(&d
, cpu_map
, attr
, sd
, i
);
7121 sd
= __build_book_sched_domain(&d
, cpu_map
, attr
, sd
, i
);
7122 sd
= __build_mc_sched_domain(&d
, cpu_map
, attr
, sd
, i
);
7123 sd
= __build_smt_sched_domain(&d
, cpu_map
, attr
, sd
, i
);
7126 for_each_cpu(i
, cpu_map
) {
7127 build_sched_groups(&d
, SD_LV_SIBLING
, cpu_map
, i
);
7128 build_sched_groups(&d
, SD_LV_BOOK
, cpu_map
, i
);
7129 build_sched_groups(&d
, SD_LV_MC
, cpu_map
, i
);
7132 /* Set up physical groups */
7133 for (i
= 0; i
< nr_node_ids
; i
++)
7134 build_sched_groups(&d
, SD_LV_CPU
, cpu_map
, i
);
7137 /* Set up node groups */
7139 build_sched_groups(&d
, SD_LV_ALLNODES
, cpu_map
, 0);
7141 for (i
= 0; i
< nr_node_ids
; i
++)
7142 if (build_numa_sched_groups(&d
, cpu_map
, i
))
7146 /* Calculate CPU power for physical packages and nodes */
7147 #ifdef CONFIG_SCHED_SMT
7148 for_each_cpu(i
, cpu_map
) {
7149 sd
= &per_cpu(cpu_domains
, i
).sd
;
7150 init_sched_groups_power(i
, sd
);
7153 #ifdef CONFIG_SCHED_MC
7154 for_each_cpu(i
, cpu_map
) {
7155 sd
= &per_cpu(core_domains
, i
).sd
;
7156 init_sched_groups_power(i
, sd
);
7159 #ifdef CONFIG_SCHED_BOOK
7160 for_each_cpu(i
, cpu_map
) {
7161 sd
= &per_cpu(book_domains
, i
).sd
;
7162 init_sched_groups_power(i
, sd
);
7166 for_each_cpu(i
, cpu_map
) {
7167 sd
= &per_cpu(phys_domains
, i
).sd
;
7168 init_sched_groups_power(i
, sd
);
7172 for (i
= 0; i
< nr_node_ids
; i
++)
7173 init_numa_sched_groups_power(d
.sched_group_nodes
[i
]);
7175 if (d
.sd_allnodes
) {
7176 struct sched_group
*sg
;
7178 cpu_to_allnodes_group(cpumask_first(cpu_map
), cpu_map
, &sg
,
7180 init_numa_sched_groups_power(sg
);
7184 /* Attach the domains */
7185 for_each_cpu(i
, cpu_map
) {
7186 #ifdef CONFIG_SCHED_SMT
7187 sd
= &per_cpu(cpu_domains
, i
).sd
;
7188 #elif defined(CONFIG_SCHED_MC)
7189 sd
= &per_cpu(core_domains
, i
).sd
;
7190 #elif defined(CONFIG_SCHED_BOOK)
7191 sd
= &per_cpu(book_domains
, i
).sd
;
7193 sd
= &per_cpu(phys_domains
, i
).sd
;
7195 cpu_attach_domain(sd
, d
.rd
, i
);
7198 d
.sched_group_nodes
= NULL
; /* don't free this we still need it */
7199 __free_domain_allocs(&d
, sa_tmpmask
, cpu_map
);
7203 __free_domain_allocs(&d
, alloc_state
, cpu_map
);
7207 static int build_sched_domains(const struct cpumask
*cpu_map
)
7209 return __build_sched_domains(cpu_map
, NULL
);
7212 static cpumask_var_t
*doms_cur
; /* current sched domains */
7213 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
7214 static struct sched_domain_attr
*dattr_cur
;
7215 /* attribues of custom domains in 'doms_cur' */
7218 * Special case: If a kmalloc of a doms_cur partition (array of
7219 * cpumask) fails, then fallback to a single sched domain,
7220 * as determined by the single cpumask fallback_doms.
7222 static cpumask_var_t fallback_doms
;
7225 * arch_update_cpu_topology lets virtualized architectures update the
7226 * cpu core maps. It is supposed to return 1 if the topology changed
7227 * or 0 if it stayed the same.
7229 int __attribute__((weak
)) arch_update_cpu_topology(void)
7234 cpumask_var_t
*alloc_sched_domains(unsigned int ndoms
)
7237 cpumask_var_t
*doms
;
7239 doms
= kmalloc(sizeof(*doms
) * ndoms
, GFP_KERNEL
);
7242 for (i
= 0; i
< ndoms
; i
++) {
7243 if (!alloc_cpumask_var(&doms
[i
], GFP_KERNEL
)) {
7244 free_sched_domains(doms
, i
);
7251 void free_sched_domains(cpumask_var_t doms
[], unsigned int ndoms
)
7254 for (i
= 0; i
< ndoms
; i
++)
7255 free_cpumask_var(doms
[i
]);
7260 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
7261 * For now this just excludes isolated cpus, but could be used to
7262 * exclude other special cases in the future.
7264 static int arch_init_sched_domains(const struct cpumask
*cpu_map
)
7268 arch_update_cpu_topology();
7270 doms_cur
= alloc_sched_domains(ndoms_cur
);
7272 doms_cur
= &fallback_doms
;
7273 cpumask_andnot(doms_cur
[0], cpu_map
, cpu_isolated_map
);
7275 err
= build_sched_domains(doms_cur
[0]);
7276 register_sched_domain_sysctl();
7281 static void arch_destroy_sched_domains(const struct cpumask
*cpu_map
,
7282 struct cpumask
*tmpmask
)
7284 free_sched_groups(cpu_map
, tmpmask
);
7288 * Detach sched domains from a group of cpus specified in cpu_map
7289 * These cpus will now be attached to the NULL domain
7291 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
7293 /* Save because hotplug lock held. */
7294 static DECLARE_BITMAP(tmpmask
, CONFIG_NR_CPUS
);
7297 for_each_cpu(i
, cpu_map
)
7298 cpu_attach_domain(NULL
, &def_root_domain
, i
);
7299 synchronize_sched();
7300 arch_destroy_sched_domains(cpu_map
, to_cpumask(tmpmask
));
7303 /* handle null as "default" */
7304 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
7305 struct sched_domain_attr
*new, int idx_new
)
7307 struct sched_domain_attr tmp
;
7314 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
7315 new ? (new + idx_new
) : &tmp
,
7316 sizeof(struct sched_domain_attr
));
7320 * Partition sched domains as specified by the 'ndoms_new'
7321 * cpumasks in the array doms_new[] of cpumasks. This compares
7322 * doms_new[] to the current sched domain partitioning, doms_cur[].
7323 * It destroys each deleted domain and builds each new domain.
7325 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
7326 * The masks don't intersect (don't overlap.) We should setup one
7327 * sched domain for each mask. CPUs not in any of the cpumasks will
7328 * not be load balanced. If the same cpumask appears both in the
7329 * current 'doms_cur' domains and in the new 'doms_new', we can leave
7332 * The passed in 'doms_new' should be allocated using
7333 * alloc_sched_domains. This routine takes ownership of it and will
7334 * free_sched_domains it when done with it. If the caller failed the
7335 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
7336 * and partition_sched_domains() will fallback to the single partition
7337 * 'fallback_doms', it also forces the domains to be rebuilt.
7339 * If doms_new == NULL it will be replaced with cpu_online_mask.
7340 * ndoms_new == 0 is a special case for destroying existing domains,
7341 * and it will not create the default domain.
7343 * Call with hotplug lock held
7345 void partition_sched_domains(int ndoms_new
, cpumask_var_t doms_new
[],
7346 struct sched_domain_attr
*dattr_new
)
7351 mutex_lock(&sched_domains_mutex
);
7353 /* always unregister in case we don't destroy any domains */
7354 unregister_sched_domain_sysctl();
7356 /* Let architecture update cpu core mappings. */
7357 new_topology
= arch_update_cpu_topology();
7359 n
= doms_new
? ndoms_new
: 0;
7361 /* Destroy deleted domains */
7362 for (i
= 0; i
< ndoms_cur
; i
++) {
7363 for (j
= 0; j
< n
&& !new_topology
; j
++) {
7364 if (cpumask_equal(doms_cur
[i
], doms_new
[j
])
7365 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
7368 /* no match - a current sched domain not in new doms_new[] */
7369 detach_destroy_domains(doms_cur
[i
]);
7374 if (doms_new
== NULL
) {
7376 doms_new
= &fallback_doms
;
7377 cpumask_andnot(doms_new
[0], cpu_active_mask
, cpu_isolated_map
);
7378 WARN_ON_ONCE(dattr_new
);
7381 /* Build new domains */
7382 for (i
= 0; i
< ndoms_new
; i
++) {
7383 for (j
= 0; j
< ndoms_cur
&& !new_topology
; j
++) {
7384 if (cpumask_equal(doms_new
[i
], doms_cur
[j
])
7385 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
7388 /* no match - add a new doms_new */
7389 __build_sched_domains(doms_new
[i
],
7390 dattr_new
? dattr_new
+ i
: NULL
);
7395 /* Remember the new sched domains */
7396 if (doms_cur
!= &fallback_doms
)
7397 free_sched_domains(doms_cur
, ndoms_cur
);
7398 kfree(dattr_cur
); /* kfree(NULL) is safe */
7399 doms_cur
= doms_new
;
7400 dattr_cur
= dattr_new
;
7401 ndoms_cur
= ndoms_new
;
7403 register_sched_domain_sysctl();
7405 mutex_unlock(&sched_domains_mutex
);
7408 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
7409 static void arch_reinit_sched_domains(void)
7413 /* Destroy domains first to force the rebuild */
7414 partition_sched_domains(0, NULL
, NULL
);
7416 rebuild_sched_domains();
7420 static ssize_t
sched_power_savings_store(const char *buf
, size_t count
, int smt
)
7422 unsigned int level
= 0;
7424 if (sscanf(buf
, "%u", &level
) != 1)
7428 * level is always be positive so don't check for
7429 * level < POWERSAVINGS_BALANCE_NONE which is 0
7430 * What happens on 0 or 1 byte write,
7431 * need to check for count as well?
7434 if (level
>= MAX_POWERSAVINGS_BALANCE_LEVELS
)
7438 sched_smt_power_savings
= level
;
7440 sched_mc_power_savings
= level
;
7442 arch_reinit_sched_domains();
7447 #ifdef CONFIG_SCHED_MC
7448 static ssize_t
sched_mc_power_savings_show(struct sysdev_class
*class,
7449 struct sysdev_class_attribute
*attr
,
7452 return sprintf(page
, "%u\n", sched_mc_power_savings
);
7454 static ssize_t
sched_mc_power_savings_store(struct sysdev_class
*class,
7455 struct sysdev_class_attribute
*attr
,
7456 const char *buf
, size_t count
)
7458 return sched_power_savings_store(buf
, count
, 0);
7460 static SYSDEV_CLASS_ATTR(sched_mc_power_savings
, 0644,
7461 sched_mc_power_savings_show
,
7462 sched_mc_power_savings_store
);
7465 #ifdef CONFIG_SCHED_SMT
7466 static ssize_t
sched_smt_power_savings_show(struct sysdev_class
*dev
,
7467 struct sysdev_class_attribute
*attr
,
7470 return sprintf(page
, "%u\n", sched_smt_power_savings
);
7472 static ssize_t
sched_smt_power_savings_store(struct sysdev_class
*dev
,
7473 struct sysdev_class_attribute
*attr
,
7474 const char *buf
, size_t count
)
7476 return sched_power_savings_store(buf
, count
, 1);
7478 static SYSDEV_CLASS_ATTR(sched_smt_power_savings
, 0644,
7479 sched_smt_power_savings_show
,
7480 sched_smt_power_savings_store
);
7483 int __init
sched_create_sysfs_power_savings_entries(struct sysdev_class
*cls
)
7487 #ifdef CONFIG_SCHED_SMT
7489 err
= sysfs_create_file(&cls
->kset
.kobj
,
7490 &attr_sched_smt_power_savings
.attr
);
7492 #ifdef CONFIG_SCHED_MC
7493 if (!err
&& mc_capable())
7494 err
= sysfs_create_file(&cls
->kset
.kobj
,
7495 &attr_sched_mc_power_savings
.attr
);
7499 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
7502 * Update cpusets according to cpu_active mask. If cpusets are
7503 * disabled, cpuset_update_active_cpus() becomes a simple wrapper
7504 * around partition_sched_domains().
7506 static int cpuset_cpu_active(struct notifier_block
*nfb
, unsigned long action
,
7509 switch (action
& ~CPU_TASKS_FROZEN
) {
7511 case CPU_DOWN_FAILED
:
7512 cpuset_update_active_cpus();
7519 static int cpuset_cpu_inactive(struct notifier_block
*nfb
, unsigned long action
,
7522 switch (action
& ~CPU_TASKS_FROZEN
) {
7523 case CPU_DOWN_PREPARE
:
7524 cpuset_update_active_cpus();
7531 static int update_runtime(struct notifier_block
*nfb
,
7532 unsigned long action
, void *hcpu
)
7534 int cpu
= (int)(long)hcpu
;
7537 case CPU_DOWN_PREPARE
:
7538 case CPU_DOWN_PREPARE_FROZEN
:
7539 disable_runtime(cpu_rq(cpu
));
7542 case CPU_DOWN_FAILED
:
7543 case CPU_DOWN_FAILED_FROZEN
:
7545 case CPU_ONLINE_FROZEN
:
7546 enable_runtime(cpu_rq(cpu
));
7554 void __init
sched_init_smp(void)
7556 cpumask_var_t non_isolated_cpus
;
7558 alloc_cpumask_var(&non_isolated_cpus
, GFP_KERNEL
);
7559 alloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
7561 #if defined(CONFIG_NUMA)
7562 sched_group_nodes_bycpu
= kzalloc(nr_cpu_ids
* sizeof(void **),
7564 BUG_ON(sched_group_nodes_bycpu
== NULL
);
7567 mutex_lock(&sched_domains_mutex
);
7568 arch_init_sched_domains(cpu_active_mask
);
7569 cpumask_andnot(non_isolated_cpus
, cpu_possible_mask
, cpu_isolated_map
);
7570 if (cpumask_empty(non_isolated_cpus
))
7571 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus
);
7572 mutex_unlock(&sched_domains_mutex
);
7575 hotcpu_notifier(cpuset_cpu_active
, CPU_PRI_CPUSET_ACTIVE
);
7576 hotcpu_notifier(cpuset_cpu_inactive
, CPU_PRI_CPUSET_INACTIVE
);
7578 /* RT runtime code needs to handle some hotplug events */
7579 hotcpu_notifier(update_runtime
, 0);
7583 /* Move init over to a non-isolated CPU */
7584 if (set_cpus_allowed_ptr(current
, non_isolated_cpus
) < 0)
7586 sched_init_granularity();
7587 free_cpumask_var(non_isolated_cpus
);
7589 init_sched_rt_class();
7592 void __init
sched_init_smp(void)
7594 sched_init_granularity();
7596 #endif /* CONFIG_SMP */
7598 const_debug
unsigned int sysctl_timer_migration
= 1;
7600 int in_sched_functions(unsigned long addr
)
7602 return in_lock_functions(addr
) ||
7603 (addr
>= (unsigned long)__sched_text_start
7604 && addr
< (unsigned long)__sched_text_end
);
7607 static void init_cfs_rq(struct cfs_rq
*cfs_rq
, struct rq
*rq
)
7609 cfs_rq
->tasks_timeline
= RB_ROOT
;
7610 INIT_LIST_HEAD(&cfs_rq
->tasks
);
7611 #ifdef CONFIG_FAIR_GROUP_SCHED
7614 cfs_rq
->min_vruntime
= (u64
)(-(1LL << 20));
7617 static void init_rt_rq(struct rt_rq
*rt_rq
, struct rq
*rq
)
7619 struct rt_prio_array
*array
;
7622 array
= &rt_rq
->active
;
7623 for (i
= 0; i
< MAX_RT_PRIO
; i
++) {
7624 INIT_LIST_HEAD(array
->queue
+ i
);
7625 __clear_bit(i
, array
->bitmap
);
7627 /* delimiter for bitsearch: */
7628 __set_bit(MAX_RT_PRIO
, array
->bitmap
);
7630 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
7631 rt_rq
->highest_prio
.curr
= MAX_RT_PRIO
;
7633 rt_rq
->highest_prio
.next
= MAX_RT_PRIO
;
7637 rt_rq
->rt_nr_migratory
= 0;
7638 rt_rq
->overloaded
= 0;
7639 plist_head_init_raw(&rt_rq
->pushable_tasks
, &rq
->lock
);
7643 rt_rq
->rt_throttled
= 0;
7644 rt_rq
->rt_runtime
= 0;
7645 raw_spin_lock_init(&rt_rq
->rt_runtime_lock
);
7647 #ifdef CONFIG_RT_GROUP_SCHED
7648 rt_rq
->rt_nr_boosted
= 0;
7653 #ifdef CONFIG_FAIR_GROUP_SCHED
7654 static void init_tg_cfs_entry(struct task_group
*tg
, struct cfs_rq
*cfs_rq
,
7655 struct sched_entity
*se
, int cpu
,
7656 struct sched_entity
*parent
)
7658 struct rq
*rq
= cpu_rq(cpu
);
7659 tg
->cfs_rq
[cpu
] = cfs_rq
;
7660 init_cfs_rq(cfs_rq
, rq
);
7664 /* se could be NULL for init_task_group */
7669 se
->cfs_rq
= &rq
->cfs
;
7671 se
->cfs_rq
= parent
->my_q
;
7674 update_load_set(&se
->load
, 0);
7675 se
->parent
= parent
;
7679 #ifdef CONFIG_RT_GROUP_SCHED
7680 static void init_tg_rt_entry(struct task_group
*tg
, struct rt_rq
*rt_rq
,
7681 struct sched_rt_entity
*rt_se
, int cpu
,
7682 struct sched_rt_entity
*parent
)
7684 struct rq
*rq
= cpu_rq(cpu
);
7686 tg
->rt_rq
[cpu
] = rt_rq
;
7687 init_rt_rq(rt_rq
, rq
);
7689 rt_rq
->rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
7691 tg
->rt_se
[cpu
] = rt_se
;
7696 rt_se
->rt_rq
= &rq
->rt
;
7698 rt_se
->rt_rq
= parent
->my_q
;
7700 rt_se
->my_q
= rt_rq
;
7701 rt_se
->parent
= parent
;
7702 INIT_LIST_HEAD(&rt_se
->run_list
);
7706 void __init
sched_init(void)
7709 unsigned long alloc_size
= 0, ptr
;
7711 #ifdef CONFIG_FAIR_GROUP_SCHED
7712 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
7714 #ifdef CONFIG_RT_GROUP_SCHED
7715 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
7717 #ifdef CONFIG_CPUMASK_OFFSTACK
7718 alloc_size
+= num_possible_cpus() * cpumask_size();
7721 ptr
= (unsigned long)kzalloc(alloc_size
, GFP_NOWAIT
);
7723 #ifdef CONFIG_FAIR_GROUP_SCHED
7724 init_task_group
.se
= (struct sched_entity
**)ptr
;
7725 ptr
+= nr_cpu_ids
* sizeof(void **);
7727 init_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
7728 ptr
+= nr_cpu_ids
* sizeof(void **);
7730 #endif /* CONFIG_FAIR_GROUP_SCHED */
7731 #ifdef CONFIG_RT_GROUP_SCHED
7732 init_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
7733 ptr
+= nr_cpu_ids
* sizeof(void **);
7735 init_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
7736 ptr
+= nr_cpu_ids
* sizeof(void **);
7738 #endif /* CONFIG_RT_GROUP_SCHED */
7739 #ifdef CONFIG_CPUMASK_OFFSTACK
7740 for_each_possible_cpu(i
) {
7741 per_cpu(load_balance_tmpmask
, i
) = (void *)ptr
;
7742 ptr
+= cpumask_size();
7744 #endif /* CONFIG_CPUMASK_OFFSTACK */
7748 init_defrootdomain();
7751 init_rt_bandwidth(&def_rt_bandwidth
,
7752 global_rt_period(), global_rt_runtime());
7754 #ifdef CONFIG_RT_GROUP_SCHED
7755 init_rt_bandwidth(&init_task_group
.rt_bandwidth
,
7756 global_rt_period(), global_rt_runtime());
7757 #endif /* CONFIG_RT_GROUP_SCHED */
7759 #ifdef CONFIG_CGROUP_SCHED
7760 list_add(&init_task_group
.list
, &task_groups
);
7761 INIT_LIST_HEAD(&init_task_group
.children
);
7762 autogroup_init(&init_task
);
7763 #endif /* CONFIG_CGROUP_SCHED */
7765 for_each_possible_cpu(i
) {
7769 raw_spin_lock_init(&rq
->lock
);
7771 rq
->calc_load_active
= 0;
7772 rq
->calc_load_update
= jiffies
+ LOAD_FREQ
;
7773 init_cfs_rq(&rq
->cfs
, rq
);
7774 init_rt_rq(&rq
->rt
, rq
);
7775 #ifdef CONFIG_FAIR_GROUP_SCHED
7776 init_task_group
.shares
= init_task_group_load
;
7777 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
7778 #ifdef CONFIG_CGROUP_SCHED
7780 * How much cpu bandwidth does init_task_group get?
7782 * In case of task-groups formed thr' the cgroup filesystem, it
7783 * gets 100% of the cpu resources in the system. This overall
7784 * system cpu resource is divided among the tasks of
7785 * init_task_group and its child task-groups in a fair manner,
7786 * based on each entity's (task or task-group's) weight
7787 * (se->load.weight).
7789 * In other words, if init_task_group has 10 tasks of weight
7790 * 1024) and two child groups A0 and A1 (of weight 1024 each),
7791 * then A0's share of the cpu resource is:
7793 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
7795 * We achieve this by letting init_task_group's tasks sit
7796 * directly in rq->cfs (i.e init_task_group->se[] = NULL).
7798 init_tg_cfs_entry(&init_task_group
, &rq
->cfs
, NULL
, i
, NULL
);
7800 #endif /* CONFIG_FAIR_GROUP_SCHED */
7802 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
7803 #ifdef CONFIG_RT_GROUP_SCHED
7804 INIT_LIST_HEAD(&rq
->leaf_rt_rq_list
);
7805 #ifdef CONFIG_CGROUP_SCHED
7806 init_tg_rt_entry(&init_task_group
, &rq
->rt
, NULL
, i
, NULL
);
7810 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
7811 rq
->cpu_load
[j
] = 0;
7813 rq
->last_load_update_tick
= jiffies
;
7818 rq
->cpu_power
= SCHED_LOAD_SCALE
;
7819 rq
->post_schedule
= 0;
7820 rq
->active_balance
= 0;
7821 rq
->next_balance
= jiffies
;
7826 rq
->avg_idle
= 2*sysctl_sched_migration_cost
;
7827 rq_attach_root(rq
, &def_root_domain
);
7829 rq
->nohz_balance_kick
= 0;
7830 init_sched_softirq_csd(&per_cpu(remote_sched_softirq_cb
, i
));
7834 atomic_set(&rq
->nr_iowait
, 0);
7837 set_load_weight(&init_task
);
7839 #ifdef CONFIG_PREEMPT_NOTIFIERS
7840 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
7844 open_softirq(SCHED_SOFTIRQ
, run_rebalance_domains
);
7847 #ifdef CONFIG_RT_MUTEXES
7848 plist_head_init_raw(&init_task
.pi_waiters
, &init_task
.pi_lock
);
7852 * The boot idle thread does lazy MMU switching as well:
7854 atomic_inc(&init_mm
.mm_count
);
7855 enter_lazy_tlb(&init_mm
, current
);
7858 * Make us the idle thread. Technically, schedule() should not be
7859 * called from this thread, however somewhere below it might be,
7860 * but because we are the idle thread, we just pick up running again
7861 * when this runqueue becomes "idle".
7863 init_idle(current
, smp_processor_id());
7865 calc_load_update
= jiffies
+ LOAD_FREQ
;
7868 * During early bootup we pretend to be a normal task:
7870 current
->sched_class
= &fair_sched_class
;
7872 /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */
7873 zalloc_cpumask_var(&nohz_cpu_mask
, GFP_NOWAIT
);
7876 zalloc_cpumask_var(&nohz
.idle_cpus_mask
, GFP_NOWAIT
);
7877 alloc_cpumask_var(&nohz
.grp_idle_mask
, GFP_NOWAIT
);
7878 atomic_set(&nohz
.load_balancer
, nr_cpu_ids
);
7879 atomic_set(&nohz
.first_pick_cpu
, nr_cpu_ids
);
7880 atomic_set(&nohz
.second_pick_cpu
, nr_cpu_ids
);
7882 /* May be allocated at isolcpus cmdline parse time */
7883 if (cpu_isolated_map
== NULL
)
7884 zalloc_cpumask_var(&cpu_isolated_map
, GFP_NOWAIT
);
7889 scheduler_running
= 1;
7892 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
7893 static inline int preempt_count_equals(int preempt_offset
)
7895 int nested
= (preempt_count() & ~PREEMPT_ACTIVE
) + rcu_preempt_depth();
7897 return (nested
== PREEMPT_INATOMIC_BASE
+ preempt_offset
);
7900 void __might_sleep(const char *file
, int line
, int preempt_offset
)
7903 static unsigned long prev_jiffy
; /* ratelimiting */
7905 if ((preempt_count_equals(preempt_offset
) && !irqs_disabled()) ||
7906 system_state
!= SYSTEM_RUNNING
|| oops_in_progress
)
7908 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
7910 prev_jiffy
= jiffies
;
7913 "BUG: sleeping function called from invalid context at %s:%d\n",
7916 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
7917 in_atomic(), irqs_disabled(),
7918 current
->pid
, current
->comm
);
7920 debug_show_held_locks(current
);
7921 if (irqs_disabled())
7922 print_irqtrace_events(current
);
7926 EXPORT_SYMBOL(__might_sleep
);
7929 #ifdef CONFIG_MAGIC_SYSRQ
7930 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
7934 on_rq
= p
->se
.on_rq
;
7936 deactivate_task(rq
, p
, 0);
7937 __setscheduler(rq
, p
, SCHED_NORMAL
, 0);
7939 activate_task(rq
, p
, 0);
7940 resched_task(rq
->curr
);
7944 void normalize_rt_tasks(void)
7946 struct task_struct
*g
, *p
;
7947 unsigned long flags
;
7950 read_lock_irqsave(&tasklist_lock
, flags
);
7951 do_each_thread(g
, p
) {
7953 * Only normalize user tasks:
7958 p
->se
.exec_start
= 0;
7959 #ifdef CONFIG_SCHEDSTATS
7960 p
->se
.statistics
.wait_start
= 0;
7961 p
->se
.statistics
.sleep_start
= 0;
7962 p
->se
.statistics
.block_start
= 0;
7967 * Renice negative nice level userspace
7970 if (TASK_NICE(p
) < 0 && p
->mm
)
7971 set_user_nice(p
, 0);
7975 raw_spin_lock(&p
->pi_lock
);
7976 rq
= __task_rq_lock(p
);
7978 normalize_task(rq
, p
);
7980 __task_rq_unlock(rq
);
7981 raw_spin_unlock(&p
->pi_lock
);
7982 } while_each_thread(g
, p
);
7984 read_unlock_irqrestore(&tasklist_lock
, flags
);
7987 #endif /* CONFIG_MAGIC_SYSRQ */
7989 #if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
7991 * These functions are only useful for the IA64 MCA handling, or kdb.
7993 * They can only be called when the whole system has been
7994 * stopped - every CPU needs to be quiescent, and no scheduling
7995 * activity can take place. Using them for anything else would
7996 * be a serious bug, and as a result, they aren't even visible
7997 * under any other configuration.
8001 * curr_task - return the current task for a given cpu.
8002 * @cpu: the processor in question.
8004 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
8006 struct task_struct
*curr_task(int cpu
)
8008 return cpu_curr(cpu
);
8011 #endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
8015 * set_curr_task - set the current task for a given cpu.
8016 * @cpu: the processor in question.
8017 * @p: the task pointer to set.
8019 * Description: This function must only be used when non-maskable interrupts
8020 * are serviced on a separate stack. It allows the architecture to switch the
8021 * notion of the current task on a cpu in a non-blocking manner. This function
8022 * must be called with all CPU's synchronized, and interrupts disabled, the
8023 * and caller must save the original value of the current task (see
8024 * curr_task() above) and restore that value before reenabling interrupts and
8025 * re-starting the system.
8027 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
8029 void set_curr_task(int cpu
, struct task_struct
*p
)
8036 #ifdef CONFIG_FAIR_GROUP_SCHED
8037 static void free_fair_sched_group(struct task_group
*tg
)
8041 for_each_possible_cpu(i
) {
8043 kfree(tg
->cfs_rq
[i
]);
8053 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8055 struct cfs_rq
*cfs_rq
;
8056 struct sched_entity
*se
;
8060 tg
->cfs_rq
= kzalloc(sizeof(cfs_rq
) * nr_cpu_ids
, GFP_KERNEL
);
8063 tg
->se
= kzalloc(sizeof(se
) * nr_cpu_ids
, GFP_KERNEL
);
8067 tg
->shares
= NICE_0_LOAD
;
8069 for_each_possible_cpu(i
) {
8072 cfs_rq
= kzalloc_node(sizeof(struct cfs_rq
),
8073 GFP_KERNEL
, cpu_to_node(i
));
8077 se
= kzalloc_node(sizeof(struct sched_entity
),
8078 GFP_KERNEL
, cpu_to_node(i
));
8082 init_tg_cfs_entry(tg
, cfs_rq
, se
, i
, parent
->se
[i
]);
8093 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
8095 struct rq
*rq
= cpu_rq(cpu
);
8096 unsigned long flags
;
8099 * Only empty task groups can be destroyed; so we can speculatively
8100 * check on_list without danger of it being re-added.
8102 if (!tg
->cfs_rq
[cpu
]->on_list
)
8105 raw_spin_lock_irqsave(&rq
->lock
, flags
);
8106 list_del_leaf_cfs_rq(tg
->cfs_rq
[cpu
]);
8107 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
8109 #else /* !CONFG_FAIR_GROUP_SCHED */
8110 static inline void free_fair_sched_group(struct task_group
*tg
)
8115 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8120 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
8123 #endif /* CONFIG_FAIR_GROUP_SCHED */
8125 #ifdef CONFIG_RT_GROUP_SCHED
8126 static void free_rt_sched_group(struct task_group
*tg
)
8130 destroy_rt_bandwidth(&tg
->rt_bandwidth
);
8132 for_each_possible_cpu(i
) {
8134 kfree(tg
->rt_rq
[i
]);
8136 kfree(tg
->rt_se
[i
]);
8144 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8146 struct rt_rq
*rt_rq
;
8147 struct sched_rt_entity
*rt_se
;
8151 tg
->rt_rq
= kzalloc(sizeof(rt_rq
) * nr_cpu_ids
, GFP_KERNEL
);
8154 tg
->rt_se
= kzalloc(sizeof(rt_se
) * nr_cpu_ids
, GFP_KERNEL
);
8158 init_rt_bandwidth(&tg
->rt_bandwidth
,
8159 ktime_to_ns(def_rt_bandwidth
.rt_period
), 0);
8161 for_each_possible_cpu(i
) {
8164 rt_rq
= kzalloc_node(sizeof(struct rt_rq
),
8165 GFP_KERNEL
, cpu_to_node(i
));
8169 rt_se
= kzalloc_node(sizeof(struct sched_rt_entity
),
8170 GFP_KERNEL
, cpu_to_node(i
));
8174 init_tg_rt_entry(tg
, rt_rq
, rt_se
, i
, parent
->rt_se
[i
]);
8184 #else /* !CONFIG_RT_GROUP_SCHED */
8185 static inline void free_rt_sched_group(struct task_group
*tg
)
8190 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8194 #endif /* CONFIG_RT_GROUP_SCHED */
8196 #ifdef CONFIG_CGROUP_SCHED
8197 static void free_sched_group(struct task_group
*tg
)
8199 free_fair_sched_group(tg
);
8200 free_rt_sched_group(tg
);
8204 /* allocate runqueue etc for a new task group */
8205 struct task_group
*sched_create_group(struct task_group
*parent
)
8207 struct task_group
*tg
;
8208 unsigned long flags
;
8210 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
8212 return ERR_PTR(-ENOMEM
);
8214 if (!alloc_fair_sched_group(tg
, parent
))
8217 if (!alloc_rt_sched_group(tg
, parent
))
8220 spin_lock_irqsave(&task_group_lock
, flags
);
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 /* end participation in shares distribution */
8251 for_each_possible_cpu(i
)
8252 unregister_fair_sched_group(tg
, i
);
8254 spin_lock_irqsave(&task_group_lock
, flags
);
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 #ifdef CONFIG_FAIR_GROUP_SCHED
8285 if (tsk
->sched_class
->task_move_group
)
8286 tsk
->sched_class
->task_move_group(tsk
, on_rq
);
8289 set_task_rq(tsk
, task_cpu(tsk
));
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 DEFINE_MUTEX(shares_mutex
);
8303 int sched_group_set_shares(struct task_group
*tg
, unsigned long shares
)
8306 unsigned long flags
;
8309 * We can't change the weight of the root cgroup.
8314 if (shares
< MIN_SHARES
)
8315 shares
= MIN_SHARES
;
8316 else if (shares
> MAX_SHARES
)
8317 shares
= MAX_SHARES
;
8319 mutex_lock(&shares_mutex
);
8320 if (tg
->shares
== shares
)
8323 tg
->shares
= shares
;
8324 for_each_possible_cpu(i
) {
8325 struct rq
*rq
= cpu_rq(i
);
8326 struct sched_entity
*se
;
8329 /* Propagate contribution to hierarchy */
8330 raw_spin_lock_irqsave(&rq
->lock
, flags
);
8331 for_each_sched_entity(se
)
8332 update_cfs_shares(group_cfs_rq(se
), 0);
8333 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
8337 mutex_unlock(&shares_mutex
);
8341 unsigned long sched_group_shares(struct task_group
*tg
)
8347 #ifdef CONFIG_RT_GROUP_SCHED
8349 * Ensure that the real time constraints are schedulable.
8351 static DEFINE_MUTEX(rt_constraints_mutex
);
8353 static unsigned long to_ratio(u64 period
, u64 runtime
)
8355 if (runtime
== RUNTIME_INF
)
8358 return div64_u64(runtime
<< 20, period
);
8361 /* Must be called with tasklist_lock held */
8362 static inline int tg_has_rt_tasks(struct task_group
*tg
)
8364 struct task_struct
*g
, *p
;
8366 do_each_thread(g
, p
) {
8367 if (rt_task(p
) && rt_rq_of_se(&p
->rt
)->tg
== tg
)
8369 } while_each_thread(g
, p
);
8374 struct rt_schedulable_data
{
8375 struct task_group
*tg
;
8380 static int tg_schedulable(struct task_group
*tg
, void *data
)
8382 struct rt_schedulable_data
*d
= data
;
8383 struct task_group
*child
;
8384 unsigned long total
, sum
= 0;
8385 u64 period
, runtime
;
8387 period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8388 runtime
= tg
->rt_bandwidth
.rt_runtime
;
8391 period
= d
->rt_period
;
8392 runtime
= d
->rt_runtime
;
8396 * Cannot have more runtime than the period.
8398 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
8402 * Ensure we don't starve existing RT tasks.
8404 if (rt_bandwidth_enabled() && !runtime
&& tg_has_rt_tasks(tg
))
8407 total
= to_ratio(period
, runtime
);
8410 * Nobody can have more than the global setting allows.
8412 if (total
> to_ratio(global_rt_period(), global_rt_runtime()))
8416 * The sum of our children's runtime should not exceed our own.
8418 list_for_each_entry_rcu(child
, &tg
->children
, siblings
) {
8419 period
= ktime_to_ns(child
->rt_bandwidth
.rt_period
);
8420 runtime
= child
->rt_bandwidth
.rt_runtime
;
8422 if (child
== d
->tg
) {
8423 period
= d
->rt_period
;
8424 runtime
= d
->rt_runtime
;
8427 sum
+= to_ratio(period
, runtime
);
8436 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
8438 struct rt_schedulable_data data
= {
8440 .rt_period
= period
,
8441 .rt_runtime
= runtime
,
8444 return walk_tg_tree(tg_schedulable
, tg_nop
, &data
);
8447 static int tg_set_bandwidth(struct task_group
*tg
,
8448 u64 rt_period
, u64 rt_runtime
)
8452 mutex_lock(&rt_constraints_mutex
);
8453 read_lock(&tasklist_lock
);
8454 err
= __rt_schedulable(tg
, rt_period
, rt_runtime
);
8458 raw_spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
8459 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
8460 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
8462 for_each_possible_cpu(i
) {
8463 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
8465 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
8466 rt_rq
->rt_runtime
= rt_runtime
;
8467 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
8469 raw_spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
8471 read_unlock(&tasklist_lock
);
8472 mutex_unlock(&rt_constraints_mutex
);
8477 int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
8479 u64 rt_runtime
, rt_period
;
8481 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8482 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
8483 if (rt_runtime_us
< 0)
8484 rt_runtime
= RUNTIME_INF
;
8486 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
8489 long sched_group_rt_runtime(struct task_group
*tg
)
8493 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
8496 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
8497 do_div(rt_runtime_us
, NSEC_PER_USEC
);
8498 return rt_runtime_us
;
8501 int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
8503 u64 rt_runtime
, rt_period
;
8505 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
8506 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
8511 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
8514 long sched_group_rt_period(struct task_group
*tg
)
8518 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8519 do_div(rt_period_us
, NSEC_PER_USEC
);
8520 return rt_period_us
;
8523 static int sched_rt_global_constraints(void)
8525 u64 runtime
, period
;
8528 if (sysctl_sched_rt_period
<= 0)
8531 runtime
= global_rt_runtime();
8532 period
= global_rt_period();
8535 * Sanity check on the sysctl variables.
8537 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
8540 mutex_lock(&rt_constraints_mutex
);
8541 read_lock(&tasklist_lock
);
8542 ret
= __rt_schedulable(NULL
, 0, 0);
8543 read_unlock(&tasklist_lock
);
8544 mutex_unlock(&rt_constraints_mutex
);
8549 int sched_rt_can_attach(struct task_group
*tg
, struct task_struct
*tsk
)
8551 /* Don't accept realtime tasks when there is no way for them to run */
8552 if (rt_task(tsk
) && tg
->rt_bandwidth
.rt_runtime
== 0)
8558 #else /* !CONFIG_RT_GROUP_SCHED */
8559 static int sched_rt_global_constraints(void)
8561 unsigned long flags
;
8564 if (sysctl_sched_rt_period
<= 0)
8568 * There's always some RT tasks in the root group
8569 * -- migration, kstopmachine etc..
8571 if (sysctl_sched_rt_runtime
== 0)
8574 raw_spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
8575 for_each_possible_cpu(i
) {
8576 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
8578 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
8579 rt_rq
->rt_runtime
= global_rt_runtime();
8580 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
8582 raw_spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
8586 #endif /* CONFIG_RT_GROUP_SCHED */
8588 int sched_rt_handler(struct ctl_table
*table
, int write
,
8589 void __user
*buffer
, size_t *lenp
,
8593 int old_period
, old_runtime
;
8594 static DEFINE_MUTEX(mutex
);
8597 old_period
= sysctl_sched_rt_period
;
8598 old_runtime
= sysctl_sched_rt_runtime
;
8600 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
8602 if (!ret
&& write
) {
8603 ret
= sched_rt_global_constraints();
8605 sysctl_sched_rt_period
= old_period
;
8606 sysctl_sched_rt_runtime
= old_runtime
;
8608 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
8609 def_rt_bandwidth
.rt_period
=
8610 ns_to_ktime(global_rt_period());
8613 mutex_unlock(&mutex
);
8618 #ifdef CONFIG_CGROUP_SCHED
8620 /* return corresponding task_group object of a cgroup */
8621 static inline struct task_group
*cgroup_tg(struct cgroup
*cgrp
)
8623 return container_of(cgroup_subsys_state(cgrp
, cpu_cgroup_subsys_id
),
8624 struct task_group
, css
);
8627 static struct cgroup_subsys_state
*
8628 cpu_cgroup_create(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8630 struct task_group
*tg
, *parent
;
8632 if (!cgrp
->parent
) {
8633 /* This is early initialization for the top cgroup */
8634 return &init_task_group
.css
;
8637 parent
= cgroup_tg(cgrp
->parent
);
8638 tg
= sched_create_group(parent
);
8640 return ERR_PTR(-ENOMEM
);
8646 cpu_cgroup_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8648 struct task_group
*tg
= cgroup_tg(cgrp
);
8650 sched_destroy_group(tg
);
8654 cpu_cgroup_can_attach_task(struct cgroup
*cgrp
, struct task_struct
*tsk
)
8656 #ifdef CONFIG_RT_GROUP_SCHED
8657 if (!sched_rt_can_attach(cgroup_tg(cgrp
), tsk
))
8660 /* We don't support RT-tasks being in separate groups */
8661 if (tsk
->sched_class
!= &fair_sched_class
)
8668 cpu_cgroup_can_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
8669 struct task_struct
*tsk
, bool threadgroup
)
8671 int retval
= cpu_cgroup_can_attach_task(cgrp
, tsk
);
8675 struct task_struct
*c
;
8677 list_for_each_entry_rcu(c
, &tsk
->thread_group
, thread_group
) {
8678 retval
= cpu_cgroup_can_attach_task(cgrp
, c
);
8690 cpu_cgroup_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
8691 struct cgroup
*old_cont
, struct task_struct
*tsk
,
8694 sched_move_task(tsk
);
8696 struct task_struct
*c
;
8698 list_for_each_entry_rcu(c
, &tsk
->thread_group
, thread_group
) {
8705 #ifdef CONFIG_FAIR_GROUP_SCHED
8706 static int cpu_shares_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
8709 return sched_group_set_shares(cgroup_tg(cgrp
), shareval
);
8712 static u64
cpu_shares_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
8714 struct task_group
*tg
= cgroup_tg(cgrp
);
8716 return (u64
) tg
->shares
;
8718 #endif /* CONFIG_FAIR_GROUP_SCHED */
8720 #ifdef CONFIG_RT_GROUP_SCHED
8721 static int cpu_rt_runtime_write(struct cgroup
*cgrp
, struct cftype
*cft
,
8724 return sched_group_set_rt_runtime(cgroup_tg(cgrp
), val
);
8727 static s64
cpu_rt_runtime_read(struct cgroup
*cgrp
, struct cftype
*cft
)
8729 return sched_group_rt_runtime(cgroup_tg(cgrp
));
8732 static int cpu_rt_period_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
8735 return sched_group_set_rt_period(cgroup_tg(cgrp
), rt_period_us
);
8738 static u64
cpu_rt_period_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
8740 return sched_group_rt_period(cgroup_tg(cgrp
));
8742 #endif /* CONFIG_RT_GROUP_SCHED */
8744 static struct cftype cpu_files
[] = {
8745 #ifdef CONFIG_FAIR_GROUP_SCHED
8748 .read_u64
= cpu_shares_read_u64
,
8749 .write_u64
= cpu_shares_write_u64
,
8752 #ifdef CONFIG_RT_GROUP_SCHED
8754 .name
= "rt_runtime_us",
8755 .read_s64
= cpu_rt_runtime_read
,
8756 .write_s64
= cpu_rt_runtime_write
,
8759 .name
= "rt_period_us",
8760 .read_u64
= cpu_rt_period_read_uint
,
8761 .write_u64
= cpu_rt_period_write_uint
,
8766 static int cpu_cgroup_populate(struct cgroup_subsys
*ss
, struct cgroup
*cont
)
8768 return cgroup_add_files(cont
, ss
, cpu_files
, ARRAY_SIZE(cpu_files
));
8771 struct cgroup_subsys cpu_cgroup_subsys
= {
8773 .create
= cpu_cgroup_create
,
8774 .destroy
= cpu_cgroup_destroy
,
8775 .can_attach
= cpu_cgroup_can_attach
,
8776 .attach
= cpu_cgroup_attach
,
8777 .populate
= cpu_cgroup_populate
,
8778 .subsys_id
= cpu_cgroup_subsys_id
,
8782 #endif /* CONFIG_CGROUP_SCHED */
8784 #ifdef CONFIG_CGROUP_CPUACCT
8787 * CPU accounting code for task groups.
8789 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
8790 * (balbir@in.ibm.com).
8793 /* track cpu usage of a group of tasks and its child groups */
8795 struct cgroup_subsys_state css
;
8796 /* cpuusage holds pointer to a u64-type object on every cpu */
8797 u64 __percpu
*cpuusage
;
8798 struct percpu_counter cpustat
[CPUACCT_STAT_NSTATS
];
8799 struct cpuacct
*parent
;
8802 struct cgroup_subsys cpuacct_subsys
;
8804 /* return cpu accounting group corresponding to this container */
8805 static inline struct cpuacct
*cgroup_ca(struct cgroup
*cgrp
)
8807 return container_of(cgroup_subsys_state(cgrp
, cpuacct_subsys_id
),
8808 struct cpuacct
, css
);
8811 /* return cpu accounting group to which this task belongs */
8812 static inline struct cpuacct
*task_ca(struct task_struct
*tsk
)
8814 return container_of(task_subsys_state(tsk
, cpuacct_subsys_id
),
8815 struct cpuacct
, css
);
8818 /* create a new cpu accounting group */
8819 static struct cgroup_subsys_state
*cpuacct_create(
8820 struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8822 struct cpuacct
*ca
= kzalloc(sizeof(*ca
), GFP_KERNEL
);
8828 ca
->cpuusage
= alloc_percpu(u64
);
8832 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++)
8833 if (percpu_counter_init(&ca
->cpustat
[i
], 0))
8834 goto out_free_counters
;
8837 ca
->parent
= cgroup_ca(cgrp
->parent
);
8843 percpu_counter_destroy(&ca
->cpustat
[i
]);
8844 free_percpu(ca
->cpuusage
);
8848 return ERR_PTR(-ENOMEM
);
8851 /* destroy an existing cpu accounting group */
8853 cpuacct_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8855 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8858 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++)
8859 percpu_counter_destroy(&ca
->cpustat
[i
]);
8860 free_percpu(ca
->cpuusage
);
8864 static u64
cpuacct_cpuusage_read(struct cpuacct
*ca
, int cpu
)
8866 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
8869 #ifndef CONFIG_64BIT
8871 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
8873 raw_spin_lock_irq(&cpu_rq(cpu
)->lock
);
8875 raw_spin_unlock_irq(&cpu_rq(cpu
)->lock
);
8883 static void cpuacct_cpuusage_write(struct cpuacct
*ca
, int cpu
, u64 val
)
8885 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
8887 #ifndef CONFIG_64BIT
8889 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
8891 raw_spin_lock_irq(&cpu_rq(cpu
)->lock
);
8893 raw_spin_unlock_irq(&cpu_rq(cpu
)->lock
);
8899 /* return total cpu usage (in nanoseconds) of a group */
8900 static u64
cpuusage_read(struct cgroup
*cgrp
, struct cftype
*cft
)
8902 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8903 u64 totalcpuusage
= 0;
8906 for_each_present_cpu(i
)
8907 totalcpuusage
+= cpuacct_cpuusage_read(ca
, i
);
8909 return totalcpuusage
;
8912 static int cpuusage_write(struct cgroup
*cgrp
, struct cftype
*cftype
,
8915 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8924 for_each_present_cpu(i
)
8925 cpuacct_cpuusage_write(ca
, i
, 0);
8931 static int cpuacct_percpu_seq_read(struct cgroup
*cgroup
, struct cftype
*cft
,
8934 struct cpuacct
*ca
= cgroup_ca(cgroup
);
8938 for_each_present_cpu(i
) {
8939 percpu
= cpuacct_cpuusage_read(ca
, i
);
8940 seq_printf(m
, "%llu ", (unsigned long long) percpu
);
8942 seq_printf(m
, "\n");
8946 static const char *cpuacct_stat_desc
[] = {
8947 [CPUACCT_STAT_USER
] = "user",
8948 [CPUACCT_STAT_SYSTEM
] = "system",
8951 static int cpuacct_stats_show(struct cgroup
*cgrp
, struct cftype
*cft
,
8952 struct cgroup_map_cb
*cb
)
8954 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8957 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++) {
8958 s64 val
= percpu_counter_read(&ca
->cpustat
[i
]);
8959 val
= cputime64_to_clock_t(val
);
8960 cb
->fill(cb
, cpuacct_stat_desc
[i
], val
);
8965 static struct cftype files
[] = {
8968 .read_u64
= cpuusage_read
,
8969 .write_u64
= cpuusage_write
,
8972 .name
= "usage_percpu",
8973 .read_seq_string
= cpuacct_percpu_seq_read
,
8977 .read_map
= cpuacct_stats_show
,
8981 static int cpuacct_populate(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8983 return cgroup_add_files(cgrp
, ss
, files
, ARRAY_SIZE(files
));
8987 * charge this task's execution time to its accounting group.
8989 * called with rq->lock held.
8991 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
)
8996 if (unlikely(!cpuacct_subsys
.active
))
8999 cpu
= task_cpu(tsk
);
9005 for (; ca
; ca
= ca
->parent
) {
9006 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
9007 *cpuusage
+= cputime
;
9014 * When CONFIG_VIRT_CPU_ACCOUNTING is enabled one jiffy can be very large
9015 * in cputime_t units. As a result, cpuacct_update_stats calls
9016 * percpu_counter_add with values large enough to always overflow the
9017 * per cpu batch limit causing bad SMP scalability.
9019 * To fix this we scale percpu_counter_batch by cputime_one_jiffy so we
9020 * batch the same amount of time with CONFIG_VIRT_CPU_ACCOUNTING disabled
9021 * and enabled. We cap it at INT_MAX which is the largest allowed batch value.
9024 #define CPUACCT_BATCH \
9025 min_t(long, percpu_counter_batch * cputime_one_jiffy, INT_MAX)
9027 #define CPUACCT_BATCH 0
9031 * Charge the system/user time to the task's accounting group.
9033 static void cpuacct_update_stats(struct task_struct
*tsk
,
9034 enum cpuacct_stat_index idx
, cputime_t val
)
9037 int batch
= CPUACCT_BATCH
;
9039 if (unlikely(!cpuacct_subsys
.active
))
9046 __percpu_counter_add(&ca
->cpustat
[idx
], val
, batch
);
9052 struct cgroup_subsys cpuacct_subsys
= {
9054 .create
= cpuacct_create
,
9055 .destroy
= cpuacct_destroy
,
9056 .populate
= cpuacct_populate
,
9057 .subsys_id
= cpuacct_subsys_id
,
9059 #endif /* CONFIG_CGROUP_CPUACCT */
9063 void synchronize_sched_expedited(void)
9067 EXPORT_SYMBOL_GPL(synchronize_sched_expedited
);
9069 #else /* #ifndef CONFIG_SMP */
9071 static atomic_t synchronize_sched_expedited_count
= ATOMIC_INIT(0);
9073 static int synchronize_sched_expedited_cpu_stop(void *data
)
9076 * There must be a full memory barrier on each affected CPU
9077 * between the time that try_stop_cpus() is called and the
9078 * time that it returns.
9080 * In the current initial implementation of cpu_stop, the
9081 * above condition is already met when the control reaches
9082 * this point and the following smp_mb() is not strictly
9083 * necessary. Do smp_mb() anyway for documentation and
9084 * robustness against future implementation changes.
9086 smp_mb(); /* See above comment block. */
9091 * Wait for an rcu-sched grace period to elapse, but use "big hammer"
9092 * approach to force grace period to end quickly. This consumes
9093 * significant time on all CPUs, and is thus not recommended for
9094 * any sort of common-case code.
9096 * Note that it is illegal to call this function while holding any
9097 * lock that is acquired by a CPU-hotplug notifier. Failing to
9098 * observe this restriction will result in deadlock.
9100 void synchronize_sched_expedited(void)
9102 int snap
, trycount
= 0;
9104 smp_mb(); /* ensure prior mod happens before capturing snap. */
9105 snap
= atomic_read(&synchronize_sched_expedited_count
) + 1;
9107 while (try_stop_cpus(cpu_online_mask
,
9108 synchronize_sched_expedited_cpu_stop
,
9111 if (trycount
++ < 10)
9112 udelay(trycount
* num_online_cpus());
9114 synchronize_sched();
9117 if (atomic_read(&synchronize_sched_expedited_count
) - snap
> 0) {
9118 smp_mb(); /* ensure test happens before caller kfree */
9123 atomic_inc(&synchronize_sched_expedited_count
);
9124 smp_mb__after_atomic_inc(); /* ensure post-GP actions seen after GP. */
9127 EXPORT_SYMBOL_GPL(synchronize_sched_expedited
);
9129 #endif /* #else #ifndef CONFIG_SMP */