4 * Kernel scheduler and related syscalls
6 * Copyright (C) 1991-2002 Linus Torvalds
8 * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and
9 * make semaphores SMP safe
10 * 1998-11-19 Implemented schedule_timeout() and related stuff
12 * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar:
13 * hybrid priority-list and round-robin design with
14 * an array-switch method of distributing timeslices
15 * and per-CPU runqueues. Cleanups and useful suggestions
16 * by Davide Libenzi, preemptible kernel bits by Robert Love.
17 * 2003-09-03 Interactivity tuning by Con Kolivas.
18 * 2004-04-02 Scheduler domains code by Nick Piggin
19 * 2007-04-15 Work begun on replacing all interactivity tuning with a
20 * fair scheduling design by Con Kolivas.
21 * 2007-05-05 Load balancing (smp-nice) and other improvements
23 * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith
24 * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri
25 * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins,
26 * Thomas Gleixner, Mike Kravetz
30 #include <linux/module.h>
31 #include <linux/nmi.h>
32 #include <linux/init.h>
33 #include <linux/uaccess.h>
34 #include <linux/highmem.h>
35 #include <asm/mmu_context.h>
36 #include <linux/interrupt.h>
37 #include <linux/capability.h>
38 #include <linux/completion.h>
39 #include <linux/kernel_stat.h>
40 #include <linux/debug_locks.h>
41 #include <linux/perf_event.h>
42 #include <linux/security.h>
43 #include <linux/notifier.h>
44 #include <linux/profile.h>
45 #include <linux/freezer.h>
46 #include <linux/vmalloc.h>
47 #include <linux/blkdev.h>
48 #include <linux/delay.h>
49 #include <linux/pid_namespace.h>
50 #include <linux/smp.h>
51 #include <linux/threads.h>
52 #include <linux/timer.h>
53 #include <linux/rcupdate.h>
54 #include <linux/cpu.h>
55 #include <linux/cpuset.h>
56 #include <linux/percpu.h>
57 #include <linux/proc_fs.h>
58 #include <linux/seq_file.h>
59 #include <linux/stop_machine.h>
60 #include <linux/sysctl.h>
61 #include <linux/syscalls.h>
62 #include <linux/times.h>
63 #include <linux/tsacct_kern.h>
64 #include <linux/kprobes.h>
65 #include <linux/delayacct.h>
66 #include <linux/unistd.h>
67 #include <linux/pagemap.h>
68 #include <linux/hrtimer.h>
69 #include <linux/tick.h>
70 #include <linux/debugfs.h>
71 #include <linux/ctype.h>
72 #include <linux/ftrace.h>
73 #include <linux/slab.h>
76 #include <asm/irq_regs.h>
77 #include <asm/mutex.h>
79 #include "sched_cpupri.h"
80 #include "workqueue_sched.h"
81 #include "sched_autogroup.h"
83 #define CREATE_TRACE_POINTS
84 #include <trace/events/sched.h>
87 * Convert user-nice values [ -20 ... 0 ... 19 ]
88 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
91 #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
92 #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
93 #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
96 * 'User priority' is the nice value converted to something we
97 * can work with better when scaling various scheduler parameters,
98 * it's a [ 0 ... 39 ] range.
100 #define USER_PRIO(p) ((p)-MAX_RT_PRIO)
101 #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
102 #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
105 * Helpers for converting nanosecond timing to jiffy resolution
107 #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
109 #define NICE_0_LOAD SCHED_LOAD_SCALE
110 #define NICE_0_SHIFT SCHED_LOAD_SHIFT
113 * These are the 'tuning knobs' of the scheduler:
115 * default timeslice is 100 msecs (used only for SCHED_RR tasks).
116 * Timeslices get refilled after they expire.
118 #define DEF_TIMESLICE (100 * HZ / 1000)
121 * single value that denotes runtime == period, ie unlimited time.
123 #define RUNTIME_INF ((u64)~0ULL)
125 static inline int rt_policy(int policy
)
127 if (unlikely(policy
== SCHED_FIFO
|| policy
== SCHED_RR
))
132 static inline int task_has_rt_policy(struct task_struct
*p
)
134 return rt_policy(p
->policy
);
138 * This is the priority-queue data structure of the RT scheduling class:
140 struct rt_prio_array
{
141 DECLARE_BITMAP(bitmap
, MAX_RT_PRIO
+1); /* include 1 bit for delimiter */
142 struct list_head queue
[MAX_RT_PRIO
];
145 struct rt_bandwidth
{
146 /* nests inside the rq lock: */
147 raw_spinlock_t rt_runtime_lock
;
150 struct hrtimer rt_period_timer
;
153 static struct rt_bandwidth def_rt_bandwidth
;
155 static int do_sched_rt_period_timer(struct rt_bandwidth
*rt_b
, int overrun
);
157 static enum hrtimer_restart
sched_rt_period_timer(struct hrtimer
*timer
)
159 struct rt_bandwidth
*rt_b
=
160 container_of(timer
, struct rt_bandwidth
, rt_period_timer
);
166 now
= hrtimer_cb_get_time(timer
);
167 overrun
= hrtimer_forward(timer
, now
, rt_b
->rt_period
);
172 idle
= do_sched_rt_period_timer(rt_b
, overrun
);
175 return idle
? HRTIMER_NORESTART
: HRTIMER_RESTART
;
179 void init_rt_bandwidth(struct rt_bandwidth
*rt_b
, u64 period
, u64 runtime
)
181 rt_b
->rt_period
= ns_to_ktime(period
);
182 rt_b
->rt_runtime
= runtime
;
184 raw_spin_lock_init(&rt_b
->rt_runtime_lock
);
186 hrtimer_init(&rt_b
->rt_period_timer
,
187 CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
188 rt_b
->rt_period_timer
.function
= sched_rt_period_timer
;
191 static inline int rt_bandwidth_enabled(void)
193 return sysctl_sched_rt_runtime
>= 0;
196 static void start_rt_bandwidth(struct rt_bandwidth
*rt_b
)
200 if (!rt_bandwidth_enabled() || rt_b
->rt_runtime
== RUNTIME_INF
)
203 if (hrtimer_active(&rt_b
->rt_period_timer
))
206 raw_spin_lock(&rt_b
->rt_runtime_lock
);
211 if (hrtimer_active(&rt_b
->rt_period_timer
))
214 now
= hrtimer_cb_get_time(&rt_b
->rt_period_timer
);
215 hrtimer_forward(&rt_b
->rt_period_timer
, now
, rt_b
->rt_period
);
217 soft
= hrtimer_get_softexpires(&rt_b
->rt_period_timer
);
218 hard
= hrtimer_get_expires(&rt_b
->rt_period_timer
);
219 delta
= ktime_to_ns(ktime_sub(hard
, soft
));
220 __hrtimer_start_range_ns(&rt_b
->rt_period_timer
, soft
, delta
,
221 HRTIMER_MODE_ABS_PINNED
, 0);
223 raw_spin_unlock(&rt_b
->rt_runtime_lock
);
226 #ifdef CONFIG_RT_GROUP_SCHED
227 static void destroy_rt_bandwidth(struct rt_bandwidth
*rt_b
)
229 hrtimer_cancel(&rt_b
->rt_period_timer
);
234 * sched_domains_mutex serializes calls to init_sched_domains,
235 * detach_destroy_domains and partition_sched_domains.
237 static DEFINE_MUTEX(sched_domains_mutex
);
239 #ifdef CONFIG_CGROUP_SCHED
241 #include <linux/cgroup.h>
245 static LIST_HEAD(task_groups
);
247 /* task group related information */
249 struct cgroup_subsys_state css
;
251 #ifdef CONFIG_FAIR_GROUP_SCHED
252 /* schedulable entities of this group on each cpu */
253 struct sched_entity
**se
;
254 /* runqueue "owned" by this group on each cpu */
255 struct cfs_rq
**cfs_rq
;
256 unsigned long shares
;
258 atomic_t load_weight
;
261 #ifdef CONFIG_RT_GROUP_SCHED
262 struct sched_rt_entity
**rt_se
;
263 struct rt_rq
**rt_rq
;
265 struct rt_bandwidth rt_bandwidth
;
269 struct list_head list
;
271 struct task_group
*parent
;
272 struct list_head siblings
;
273 struct list_head children
;
275 #ifdef CONFIG_SCHED_AUTOGROUP
276 struct autogroup
*autogroup
;
280 /* task_group_lock serializes the addition/removal of task groups */
281 static DEFINE_SPINLOCK(task_group_lock
);
283 #ifdef CONFIG_FAIR_GROUP_SCHED
285 # define ROOT_TASK_GROUP_LOAD NICE_0_LOAD
288 * A weight of 0 or 1 can cause arithmetics problems.
289 * A weight of a cfs_rq is the sum of weights of which entities
290 * are queued on this cfs_rq, so a weight of a entity should not be
291 * too large, so as the shares value of a task group.
292 * (The default weight is 1024 - so there's no practical
293 * limitation from this.)
296 #define MAX_SHARES (1UL << 18)
298 static int root_task_group_load
= ROOT_TASK_GROUP_LOAD
;
301 /* Default task group.
302 * Every task in system belong to this group at bootup.
304 struct task_group root_task_group
;
306 #endif /* CONFIG_CGROUP_SCHED */
308 /* CFS-related fields in a runqueue */
310 struct load_weight load
;
311 unsigned long nr_running
;
316 struct rb_root tasks_timeline
;
317 struct rb_node
*rb_leftmost
;
319 struct list_head tasks
;
320 struct list_head
*balance_iterator
;
323 * 'curr' points to currently running entity on this cfs_rq.
324 * It is set to NULL otherwise (i.e when none are currently running).
326 struct sched_entity
*curr
, *next
, *last
, *skip
;
328 unsigned int nr_spread_over
;
330 #ifdef CONFIG_FAIR_GROUP_SCHED
331 struct rq
*rq
; /* cpu runqueue to which this cfs_rq is attached */
334 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
335 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
336 * (like users, containers etc.)
338 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
339 * list is used during load balance.
342 struct list_head leaf_cfs_rq_list
;
343 struct task_group
*tg
; /* group that "owns" this runqueue */
347 * the part of load.weight contributed by tasks
349 unsigned long task_weight
;
352 * h_load = weight * f(tg)
354 * Where f(tg) is the recursive weight fraction assigned to
357 unsigned long h_load
;
360 * Maintaining per-cpu shares distribution for group scheduling
362 * load_stamp is the last time we updated the load average
363 * load_last is the last time we updated the load average and saw load
364 * load_unacc_exec_time is currently unaccounted execution time
368 u64 load_stamp
, load_last
, load_unacc_exec_time
;
370 unsigned long load_contribution
;
375 /* Real-Time classes' related field in a runqueue: */
377 struct rt_prio_array active
;
378 unsigned long rt_nr_running
;
379 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
381 int curr
; /* highest queued rt task prio */
383 int next
; /* next highest */
388 unsigned long rt_nr_migratory
;
389 unsigned long rt_nr_total
;
391 struct plist_head pushable_tasks
;
396 /* Nests inside the rq lock: */
397 raw_spinlock_t rt_runtime_lock
;
399 #ifdef CONFIG_RT_GROUP_SCHED
400 unsigned long rt_nr_boosted
;
403 struct list_head leaf_rt_rq_list
;
404 struct task_group
*tg
;
411 * We add the notion of a root-domain which will be used to define per-domain
412 * variables. Each exclusive cpuset essentially defines an island domain by
413 * fully partitioning the member cpus from any other cpuset. Whenever a new
414 * exclusive cpuset is created, we also create and attach a new root-domain
422 cpumask_var_t online
;
425 * The "RT overload" flag: it gets set if a CPU has more than
426 * one runnable RT task.
428 cpumask_var_t rto_mask
;
430 struct cpupri cpupri
;
434 * By default the system creates a single root-domain with all cpus as
435 * members (mimicking the global state we have today).
437 static struct root_domain def_root_domain
;
439 #endif /* CONFIG_SMP */
442 * This is the main, per-CPU runqueue data structure.
444 * Locking rule: those places that want to lock multiple runqueues
445 * (such as the load balancing or the thread migration code), lock
446 * acquire operations must be ordered by ascending &runqueue.
453 * nr_running and cpu_load should be in the same cacheline because
454 * remote CPUs use both these fields when doing load calculation.
456 unsigned long nr_running
;
457 #define CPU_LOAD_IDX_MAX 5
458 unsigned long cpu_load
[CPU_LOAD_IDX_MAX
];
459 unsigned long last_load_update_tick
;
462 unsigned char nohz_balance_kick
;
464 unsigned int skip_clock_update
;
466 /* capture load from *all* tasks on this cpu: */
467 struct load_weight load
;
468 unsigned long nr_load_updates
;
474 #ifdef CONFIG_FAIR_GROUP_SCHED
475 /* list of leaf cfs_rq on this cpu: */
476 struct list_head leaf_cfs_rq_list
;
478 #ifdef CONFIG_RT_GROUP_SCHED
479 struct list_head leaf_rt_rq_list
;
483 * This is part of a global counter where only the total sum
484 * over all CPUs matters. A task can increase this counter on
485 * one CPU and if it got migrated afterwards it may decrease
486 * it on another CPU. Always updated under the runqueue lock:
488 unsigned long nr_uninterruptible
;
490 struct task_struct
*curr
, *idle
, *stop
;
491 unsigned long next_balance
;
492 struct mm_struct
*prev_mm
;
500 struct root_domain
*rd
;
501 struct sched_domain
*sd
;
503 unsigned long cpu_power
;
505 unsigned char idle_at_tick
;
506 /* For active balancing */
510 struct cpu_stop_work active_balance_work
;
511 /* cpu of this runqueue: */
515 unsigned long avg_load_per_task
;
523 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
527 /* calc_load related fields */
528 unsigned long calc_load_update
;
529 long calc_load_active
;
531 #ifdef CONFIG_SCHED_HRTICK
533 int hrtick_csd_pending
;
534 struct call_single_data hrtick_csd
;
536 struct hrtimer hrtick_timer
;
539 #ifdef CONFIG_SCHEDSTATS
541 struct sched_info rq_sched_info
;
542 unsigned long long rq_cpu_time
;
543 /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
545 /* sys_sched_yield() stats */
546 unsigned int yld_count
;
548 /* schedule() stats */
549 unsigned int sched_switch
;
550 unsigned int sched_count
;
551 unsigned int sched_goidle
;
553 /* try_to_wake_up() stats */
554 unsigned int ttwu_count
;
555 unsigned int ttwu_local
;
559 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
562 static void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int flags
);
564 static inline int cpu_of(struct rq
*rq
)
573 #define rcu_dereference_check_sched_domain(p) \
574 rcu_dereference_check((p), \
575 rcu_read_lock_held() || \
576 lockdep_is_held(&sched_domains_mutex))
579 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
580 * See detach_destroy_domains: synchronize_sched for details.
582 * The domain tree of any CPU may only be accessed from within
583 * preempt-disabled sections.
585 #define for_each_domain(cpu, __sd) \
586 for (__sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
588 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
589 #define this_rq() (&__get_cpu_var(runqueues))
590 #define task_rq(p) cpu_rq(task_cpu(p))
591 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
592 #define raw_rq() (&__raw_get_cpu_var(runqueues))
594 #ifdef CONFIG_CGROUP_SCHED
597 * Return the group to which this tasks belongs.
599 * We use task_subsys_state_check() and extend the RCU verification
600 * with lockdep_is_held(&task_rq(p)->lock) because cpu_cgroup_attach()
601 * holds that lock for each task it moves into the cgroup. Therefore
602 * by holding that lock, we pin the task to the current cgroup.
604 static inline struct task_group
*task_group(struct task_struct
*p
)
606 struct task_group
*tg
;
607 struct cgroup_subsys_state
*css
;
609 css
= task_subsys_state_check(p
, cpu_cgroup_subsys_id
,
610 lockdep_is_held(&task_rq(p
)->lock
));
611 tg
= container_of(css
, struct task_group
, css
);
613 return autogroup_task_group(p
, tg
);
616 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
617 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
)
619 #ifdef CONFIG_FAIR_GROUP_SCHED
620 p
->se
.cfs_rq
= task_group(p
)->cfs_rq
[cpu
];
621 p
->se
.parent
= task_group(p
)->se
[cpu
];
624 #ifdef CONFIG_RT_GROUP_SCHED
625 p
->rt
.rt_rq
= task_group(p
)->rt_rq
[cpu
];
626 p
->rt
.parent
= task_group(p
)->rt_se
[cpu
];
630 #else /* CONFIG_CGROUP_SCHED */
632 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
) { }
633 static inline struct task_group
*task_group(struct task_struct
*p
)
638 #endif /* CONFIG_CGROUP_SCHED */
640 static void update_rq_clock_task(struct rq
*rq
, s64 delta
);
642 static void update_rq_clock(struct rq
*rq
)
646 if (rq
->skip_clock_update
)
649 delta
= sched_clock_cpu(cpu_of(rq
)) - rq
->clock
;
651 update_rq_clock_task(rq
, delta
);
655 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
657 #ifdef CONFIG_SCHED_DEBUG
658 # define const_debug __read_mostly
660 # define const_debug static const
664 * runqueue_is_locked - Returns true if the current cpu runqueue is locked
665 * @cpu: the processor in question.
667 * This interface allows printk to be called with the runqueue lock
668 * held and know whether or not it is OK to wake up the klogd.
670 int runqueue_is_locked(int cpu
)
672 return raw_spin_is_locked(&cpu_rq(cpu
)->lock
);
676 * Debugging: various feature bits
679 #define SCHED_FEAT(name, enabled) \
680 __SCHED_FEAT_##name ,
683 #include "sched_features.h"
688 #define SCHED_FEAT(name, enabled) \
689 (1UL << __SCHED_FEAT_##name) * enabled |
691 const_debug
unsigned int sysctl_sched_features
=
692 #include "sched_features.h"
697 #ifdef CONFIG_SCHED_DEBUG
698 #define SCHED_FEAT(name, enabled) \
701 static __read_mostly
char *sched_feat_names
[] = {
702 #include "sched_features.h"
708 static int sched_feat_show(struct seq_file
*m
, void *v
)
712 for (i
= 0; sched_feat_names
[i
]; i
++) {
713 if (!(sysctl_sched_features
& (1UL << i
)))
715 seq_printf(m
, "%s ", sched_feat_names
[i
]);
723 sched_feat_write(struct file
*filp
, const char __user
*ubuf
,
724 size_t cnt
, loff_t
*ppos
)
734 if (copy_from_user(&buf
, ubuf
, cnt
))
740 if (strncmp(cmp
, "NO_", 3) == 0) {
745 for (i
= 0; sched_feat_names
[i
]; i
++) {
746 if (strcmp(cmp
, sched_feat_names
[i
]) == 0) {
748 sysctl_sched_features
&= ~(1UL << i
);
750 sysctl_sched_features
|= (1UL << i
);
755 if (!sched_feat_names
[i
])
763 static int sched_feat_open(struct inode
*inode
, struct file
*filp
)
765 return single_open(filp
, sched_feat_show
, NULL
);
768 static const struct file_operations sched_feat_fops
= {
769 .open
= sched_feat_open
,
770 .write
= sched_feat_write
,
773 .release
= single_release
,
776 static __init
int sched_init_debug(void)
778 debugfs_create_file("sched_features", 0644, NULL
, NULL
,
783 late_initcall(sched_init_debug
);
787 #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
790 * Number of tasks to iterate in a single balance run.
791 * Limited because this is done with IRQs disabled.
793 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
796 * period over which we average the RT time consumption, measured
801 const_debug
unsigned int sysctl_sched_time_avg
= MSEC_PER_SEC
;
804 * period over which we measure -rt task cpu usage in us.
807 unsigned int sysctl_sched_rt_period
= 1000000;
809 static __read_mostly
int scheduler_running
;
812 * part of the period that we allow rt tasks to run in us.
815 int sysctl_sched_rt_runtime
= 950000;
817 static inline u64
global_rt_period(void)
819 return (u64
)sysctl_sched_rt_period
* NSEC_PER_USEC
;
822 static inline u64
global_rt_runtime(void)
824 if (sysctl_sched_rt_runtime
< 0)
827 return (u64
)sysctl_sched_rt_runtime
* NSEC_PER_USEC
;
830 #ifndef prepare_arch_switch
831 # define prepare_arch_switch(next) do { } while (0)
833 #ifndef finish_arch_switch
834 # define finish_arch_switch(prev) do { } while (0)
837 static inline int task_current(struct rq
*rq
, struct task_struct
*p
)
839 return rq
->curr
== p
;
842 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
843 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
845 return task_current(rq
, p
);
848 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
852 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
854 #ifdef CONFIG_DEBUG_SPINLOCK
855 /* this is a valid case when another task releases the spinlock */
856 rq
->lock
.owner
= current
;
859 * If we are tracking spinlock dependencies then we have to
860 * fix up the runqueue lock - which gets 'carried over' from
863 spin_acquire(&rq
->lock
.dep_map
, 0, 0, _THIS_IP_
);
865 raw_spin_unlock_irq(&rq
->lock
);
868 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
869 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
874 return task_current(rq
, p
);
878 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
882 * We can optimise this out completely for !SMP, because the
883 * SMP rebalancing from interrupt is the only thing that cares
888 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
889 raw_spin_unlock_irq(&rq
->lock
);
891 raw_spin_unlock(&rq
->lock
);
895 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
899 * After ->oncpu is cleared, the task can be moved to a different CPU.
900 * We must ensure this doesn't happen until the switch is completely
906 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
910 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
913 * Check whether the task is waking, we use this to synchronize ->cpus_allowed
916 static inline int task_is_waking(struct task_struct
*p
)
918 return unlikely(p
->state
== TASK_WAKING
);
922 * __task_rq_lock - lock the runqueue a given task resides on.
923 * Must be called interrupts disabled.
925 static inline struct rq
*__task_rq_lock(struct task_struct
*p
)
932 raw_spin_lock(&rq
->lock
);
933 if (likely(rq
== task_rq(p
)))
935 raw_spin_unlock(&rq
->lock
);
940 * task_rq_lock - lock the runqueue a given task resides on and disable
941 * interrupts. Note the ordering: we can safely lookup the task_rq without
942 * explicitly disabling preemption.
944 static struct rq
*task_rq_lock(struct task_struct
*p
, unsigned long *flags
)
950 local_irq_save(*flags
);
952 raw_spin_lock(&rq
->lock
);
953 if (likely(rq
== task_rq(p
)))
955 raw_spin_unlock_irqrestore(&rq
->lock
, *flags
);
959 static void __task_rq_unlock(struct rq
*rq
)
962 raw_spin_unlock(&rq
->lock
);
965 static inline void task_rq_unlock(struct rq
*rq
, unsigned long *flags
)
968 raw_spin_unlock_irqrestore(&rq
->lock
, *flags
);
972 * this_rq_lock - lock this runqueue and disable interrupts.
974 static struct rq
*this_rq_lock(void)
981 raw_spin_lock(&rq
->lock
);
986 #ifdef CONFIG_SCHED_HRTICK
988 * Use HR-timers to deliver accurate preemption points.
990 * Its all a bit involved since we cannot program an hrt while holding the
991 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
994 * When we get rescheduled we reprogram the hrtick_timer outside of the
1000 * - enabled by features
1001 * - hrtimer is actually high res
1003 static inline int hrtick_enabled(struct rq
*rq
)
1005 if (!sched_feat(HRTICK
))
1007 if (!cpu_active(cpu_of(rq
)))
1009 return hrtimer_is_hres_active(&rq
->hrtick_timer
);
1012 static void hrtick_clear(struct rq
*rq
)
1014 if (hrtimer_active(&rq
->hrtick_timer
))
1015 hrtimer_cancel(&rq
->hrtick_timer
);
1019 * High-resolution timer tick.
1020 * Runs from hardirq context with interrupts disabled.
1022 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
1024 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
1026 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1028 raw_spin_lock(&rq
->lock
);
1029 update_rq_clock(rq
);
1030 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
1031 raw_spin_unlock(&rq
->lock
);
1033 return HRTIMER_NORESTART
;
1038 * called from hardirq (IPI) context
1040 static void __hrtick_start(void *arg
)
1042 struct rq
*rq
= arg
;
1044 raw_spin_lock(&rq
->lock
);
1045 hrtimer_restart(&rq
->hrtick_timer
);
1046 rq
->hrtick_csd_pending
= 0;
1047 raw_spin_unlock(&rq
->lock
);
1051 * Called to set the hrtick timer state.
1053 * called with rq->lock held and irqs disabled
1055 static void hrtick_start(struct rq
*rq
, u64 delay
)
1057 struct hrtimer
*timer
= &rq
->hrtick_timer
;
1058 ktime_t time
= ktime_add_ns(timer
->base
->get_time(), delay
);
1060 hrtimer_set_expires(timer
, time
);
1062 if (rq
== this_rq()) {
1063 hrtimer_restart(timer
);
1064 } else if (!rq
->hrtick_csd_pending
) {
1065 __smp_call_function_single(cpu_of(rq
), &rq
->hrtick_csd
, 0);
1066 rq
->hrtick_csd_pending
= 1;
1071 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
1073 int cpu
= (int)(long)hcpu
;
1076 case CPU_UP_CANCELED
:
1077 case CPU_UP_CANCELED_FROZEN
:
1078 case CPU_DOWN_PREPARE
:
1079 case CPU_DOWN_PREPARE_FROZEN
:
1081 case CPU_DEAD_FROZEN
:
1082 hrtick_clear(cpu_rq(cpu
));
1089 static __init
void init_hrtick(void)
1091 hotcpu_notifier(hotplug_hrtick
, 0);
1095 * Called to set the hrtick timer state.
1097 * called with rq->lock held and irqs disabled
1099 static void hrtick_start(struct rq
*rq
, u64 delay
)
1101 __hrtimer_start_range_ns(&rq
->hrtick_timer
, ns_to_ktime(delay
), 0,
1102 HRTIMER_MODE_REL_PINNED
, 0);
1105 static inline void init_hrtick(void)
1108 #endif /* CONFIG_SMP */
1110 static void init_rq_hrtick(struct rq
*rq
)
1113 rq
->hrtick_csd_pending
= 0;
1115 rq
->hrtick_csd
.flags
= 0;
1116 rq
->hrtick_csd
.func
= __hrtick_start
;
1117 rq
->hrtick_csd
.info
= rq
;
1120 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1121 rq
->hrtick_timer
.function
= hrtick
;
1123 #else /* CONFIG_SCHED_HRTICK */
1124 static inline void hrtick_clear(struct rq
*rq
)
1128 static inline void init_rq_hrtick(struct rq
*rq
)
1132 static inline void init_hrtick(void)
1135 #endif /* CONFIG_SCHED_HRTICK */
1138 * resched_task - mark a task 'to be rescheduled now'.
1140 * On UP this means the setting of the need_resched flag, on SMP it
1141 * might also involve a cross-CPU call to trigger the scheduler on
1146 #ifndef tsk_is_polling
1147 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1150 static void resched_task(struct task_struct
*p
)
1154 assert_raw_spin_locked(&task_rq(p
)->lock
);
1156 if (test_tsk_need_resched(p
))
1159 set_tsk_need_resched(p
);
1162 if (cpu
== smp_processor_id())
1165 /* NEED_RESCHED must be visible before we test polling */
1167 if (!tsk_is_polling(p
))
1168 smp_send_reschedule(cpu
);
1171 static void resched_cpu(int cpu
)
1173 struct rq
*rq
= cpu_rq(cpu
);
1174 unsigned long flags
;
1176 if (!raw_spin_trylock_irqsave(&rq
->lock
, flags
))
1178 resched_task(cpu_curr(cpu
));
1179 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
1184 * In the semi idle case, use the nearest busy cpu for migrating timers
1185 * from an idle cpu. This is good for power-savings.
1187 * We don't do similar optimization for completely idle system, as
1188 * selecting an idle cpu will add more delays to the timers than intended
1189 * (as that cpu's timer base may not be uptodate wrt jiffies etc).
1191 int get_nohz_timer_target(void)
1193 int cpu
= smp_processor_id();
1195 struct sched_domain
*sd
;
1197 for_each_domain(cpu
, sd
) {
1198 for_each_cpu(i
, sched_domain_span(sd
))
1205 * When add_timer_on() enqueues a timer into the timer wheel of an
1206 * idle CPU then this timer might expire before the next timer event
1207 * which is scheduled to wake up that CPU. In case of a completely
1208 * idle system the next event might even be infinite time into the
1209 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1210 * leaves the inner idle loop so the newly added timer is taken into
1211 * account when the CPU goes back to idle and evaluates the timer
1212 * wheel for the next timer event.
1214 void wake_up_idle_cpu(int cpu
)
1216 struct rq
*rq
= cpu_rq(cpu
);
1218 if (cpu
== smp_processor_id())
1222 * This is safe, as this function is called with the timer
1223 * wheel base lock of (cpu) held. When the CPU is on the way
1224 * to idle and has not yet set rq->curr to idle then it will
1225 * be serialized on the timer wheel base lock and take the new
1226 * timer into account automatically.
1228 if (rq
->curr
!= rq
->idle
)
1232 * We can set TIF_RESCHED on the idle task of the other CPU
1233 * lockless. The worst case is that the other CPU runs the
1234 * idle task through an additional NOOP schedule()
1236 set_tsk_need_resched(rq
->idle
);
1238 /* NEED_RESCHED must be visible before we test polling */
1240 if (!tsk_is_polling(rq
->idle
))
1241 smp_send_reschedule(cpu
);
1244 #endif /* CONFIG_NO_HZ */
1246 static u64
sched_avg_period(void)
1248 return (u64
)sysctl_sched_time_avg
* NSEC_PER_MSEC
/ 2;
1251 static void sched_avg_update(struct rq
*rq
)
1253 s64 period
= sched_avg_period();
1255 while ((s64
)(rq
->clock
- rq
->age_stamp
) > period
) {
1257 * Inline assembly required to prevent the compiler
1258 * optimising this loop into a divmod call.
1259 * See __iter_div_u64_rem() for another example of this.
1261 asm("" : "+rm" (rq
->age_stamp
));
1262 rq
->age_stamp
+= period
;
1267 static void sched_rt_avg_update(struct rq
*rq
, u64 rt_delta
)
1269 rq
->rt_avg
+= rt_delta
;
1270 sched_avg_update(rq
);
1273 #else /* !CONFIG_SMP */
1274 static void resched_task(struct task_struct
*p
)
1276 assert_raw_spin_locked(&task_rq(p
)->lock
);
1277 set_tsk_need_resched(p
);
1280 static void sched_rt_avg_update(struct rq
*rq
, u64 rt_delta
)
1284 static void sched_avg_update(struct rq
*rq
)
1287 #endif /* CONFIG_SMP */
1289 #if BITS_PER_LONG == 32
1290 # define WMULT_CONST (~0UL)
1292 # define WMULT_CONST (1UL << 32)
1295 #define WMULT_SHIFT 32
1298 * Shift right and round:
1300 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1303 * delta *= weight / lw
1305 static unsigned long
1306 calc_delta_mine(unsigned long delta_exec
, unsigned long weight
,
1307 struct load_weight
*lw
)
1311 if (!lw
->inv_weight
) {
1312 if (BITS_PER_LONG
> 32 && unlikely(lw
->weight
>= WMULT_CONST
))
1315 lw
->inv_weight
= 1 + (WMULT_CONST
-lw
->weight
/2)
1319 tmp
= (u64
)delta_exec
* weight
;
1321 * Check whether we'd overflow the 64-bit multiplication:
1323 if (unlikely(tmp
> WMULT_CONST
))
1324 tmp
= SRR(SRR(tmp
, WMULT_SHIFT
/2) * lw
->inv_weight
,
1327 tmp
= SRR(tmp
* lw
->inv_weight
, WMULT_SHIFT
);
1329 return (unsigned long)min(tmp
, (u64
)(unsigned long)LONG_MAX
);
1332 static inline void update_load_add(struct load_weight
*lw
, unsigned long inc
)
1338 static inline void update_load_sub(struct load_weight
*lw
, unsigned long dec
)
1344 static inline void update_load_set(struct load_weight
*lw
, unsigned long w
)
1351 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1352 * of tasks with abnormal "nice" values across CPUs the contribution that
1353 * each task makes to its run queue's load is weighted according to its
1354 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1355 * scaled version of the new time slice allocation that they receive on time
1359 #define WEIGHT_IDLEPRIO 3
1360 #define WMULT_IDLEPRIO 1431655765
1363 * Nice levels are multiplicative, with a gentle 10% change for every
1364 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1365 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1366 * that remained on nice 0.
1368 * The "10% effect" is relative and cumulative: from _any_ nice level,
1369 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1370 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1371 * If a task goes up by ~10% and another task goes down by ~10% then
1372 * the relative distance between them is ~25%.)
1374 static const int prio_to_weight
[40] = {
1375 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1376 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1377 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1378 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1379 /* 0 */ 1024, 820, 655, 526, 423,
1380 /* 5 */ 335, 272, 215, 172, 137,
1381 /* 10 */ 110, 87, 70, 56, 45,
1382 /* 15 */ 36, 29, 23, 18, 15,
1386 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1388 * In cases where the weight does not change often, we can use the
1389 * precalculated inverse to speed up arithmetics by turning divisions
1390 * into multiplications:
1392 static const u32 prio_to_wmult
[40] = {
1393 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1394 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1395 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1396 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1397 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1398 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1399 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1400 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1403 /* Time spent by the tasks of the cpu accounting group executing in ... */
1404 enum cpuacct_stat_index
{
1405 CPUACCT_STAT_USER
, /* ... user mode */
1406 CPUACCT_STAT_SYSTEM
, /* ... kernel mode */
1408 CPUACCT_STAT_NSTATS
,
1411 #ifdef CONFIG_CGROUP_CPUACCT
1412 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
);
1413 static void cpuacct_update_stats(struct task_struct
*tsk
,
1414 enum cpuacct_stat_index idx
, cputime_t val
);
1416 static inline void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
) {}
1417 static inline void cpuacct_update_stats(struct task_struct
*tsk
,
1418 enum cpuacct_stat_index idx
, cputime_t val
) {}
1421 static inline void inc_cpu_load(struct rq
*rq
, unsigned long load
)
1423 update_load_add(&rq
->load
, load
);
1426 static inline void dec_cpu_load(struct rq
*rq
, unsigned long load
)
1428 update_load_sub(&rq
->load
, load
);
1431 #if (defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)) || defined(CONFIG_RT_GROUP_SCHED)
1432 typedef int (*tg_visitor
)(struct task_group
*, void *);
1435 * Iterate the full tree, calling @down when first entering a node and @up when
1436 * leaving it for the final time.
1438 static int walk_tg_tree(tg_visitor down
, tg_visitor up
, void *data
)
1440 struct task_group
*parent
, *child
;
1444 parent
= &root_task_group
;
1446 ret
= (*down
)(parent
, data
);
1449 list_for_each_entry_rcu(child
, &parent
->children
, siblings
) {
1456 ret
= (*up
)(parent
, data
);
1461 parent
= parent
->parent
;
1470 static int tg_nop(struct task_group
*tg
, void *data
)
1477 /* Used instead of source_load when we know the type == 0 */
1478 static unsigned long weighted_cpuload(const int cpu
)
1480 return cpu_rq(cpu
)->load
.weight
;
1484 * Return a low guess at the load of a migration-source cpu weighted
1485 * according to the scheduling class and "nice" value.
1487 * We want to under-estimate the load of migration sources, to
1488 * balance conservatively.
1490 static unsigned long source_load(int cpu
, int type
)
1492 struct rq
*rq
= cpu_rq(cpu
);
1493 unsigned long total
= weighted_cpuload(cpu
);
1495 if (type
== 0 || !sched_feat(LB_BIAS
))
1498 return min(rq
->cpu_load
[type
-1], total
);
1502 * Return a high guess at the load of a migration-target cpu weighted
1503 * according to the scheduling class and "nice" value.
1505 static unsigned long target_load(int cpu
, int type
)
1507 struct rq
*rq
= cpu_rq(cpu
);
1508 unsigned long total
= weighted_cpuload(cpu
);
1510 if (type
== 0 || !sched_feat(LB_BIAS
))
1513 return max(rq
->cpu_load
[type
-1], total
);
1516 static unsigned long power_of(int cpu
)
1518 return cpu_rq(cpu
)->cpu_power
;
1521 static int task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
);
1523 static unsigned long cpu_avg_load_per_task(int cpu
)
1525 struct rq
*rq
= cpu_rq(cpu
);
1526 unsigned long nr_running
= ACCESS_ONCE(rq
->nr_running
);
1529 rq
->avg_load_per_task
= rq
->load
.weight
/ nr_running
;
1531 rq
->avg_load_per_task
= 0;
1533 return rq
->avg_load_per_task
;
1536 #ifdef CONFIG_FAIR_GROUP_SCHED
1539 * Compute the cpu's hierarchical load factor for each task group.
1540 * This needs to be done in a top-down fashion because the load of a child
1541 * group is a fraction of its parents load.
1543 static int tg_load_down(struct task_group
*tg
, void *data
)
1546 long cpu
= (long)data
;
1549 load
= cpu_rq(cpu
)->load
.weight
;
1551 load
= tg
->parent
->cfs_rq
[cpu
]->h_load
;
1552 load
*= tg
->se
[cpu
]->load
.weight
;
1553 load
/= tg
->parent
->cfs_rq
[cpu
]->load
.weight
+ 1;
1556 tg
->cfs_rq
[cpu
]->h_load
= load
;
1561 static void update_h_load(long cpu
)
1563 walk_tg_tree(tg_load_down
, tg_nop
, (void *)cpu
);
1568 #ifdef CONFIG_PREEMPT
1570 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
);
1573 * fair double_lock_balance: Safely acquires both rq->locks in a fair
1574 * way at the expense of forcing extra atomic operations in all
1575 * invocations. This assures that the double_lock is acquired using the
1576 * same underlying policy as the spinlock_t on this architecture, which
1577 * reduces latency compared to the unfair variant below. However, it
1578 * also adds more overhead and therefore may reduce throughput.
1580 static inline int _double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1581 __releases(this_rq
->lock
)
1582 __acquires(busiest
->lock
)
1583 __acquires(this_rq
->lock
)
1585 raw_spin_unlock(&this_rq
->lock
);
1586 double_rq_lock(this_rq
, busiest
);
1593 * Unfair double_lock_balance: Optimizes throughput at the expense of
1594 * latency by eliminating extra atomic operations when the locks are
1595 * already in proper order on entry. This favors lower cpu-ids and will
1596 * grant the double lock to lower cpus over higher ids under contention,
1597 * regardless of entry order into the function.
1599 static int _double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1600 __releases(this_rq
->lock
)
1601 __acquires(busiest
->lock
)
1602 __acquires(this_rq
->lock
)
1606 if (unlikely(!raw_spin_trylock(&busiest
->lock
))) {
1607 if (busiest
< this_rq
) {
1608 raw_spin_unlock(&this_rq
->lock
);
1609 raw_spin_lock(&busiest
->lock
);
1610 raw_spin_lock_nested(&this_rq
->lock
,
1611 SINGLE_DEPTH_NESTING
);
1614 raw_spin_lock_nested(&busiest
->lock
,
1615 SINGLE_DEPTH_NESTING
);
1620 #endif /* CONFIG_PREEMPT */
1623 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
1625 static int double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1627 if (unlikely(!irqs_disabled())) {
1628 /* printk() doesn't work good under rq->lock */
1629 raw_spin_unlock(&this_rq
->lock
);
1633 return _double_lock_balance(this_rq
, busiest
);
1636 static inline void double_unlock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1637 __releases(busiest
->lock
)
1639 raw_spin_unlock(&busiest
->lock
);
1640 lock_set_subclass(&this_rq
->lock
.dep_map
, 0, _RET_IP_
);
1644 * double_rq_lock - safely lock two runqueues
1646 * Note this does not disable interrupts like task_rq_lock,
1647 * you need to do so manually before calling.
1649 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
)
1650 __acquires(rq1
->lock
)
1651 __acquires(rq2
->lock
)
1653 BUG_ON(!irqs_disabled());
1655 raw_spin_lock(&rq1
->lock
);
1656 __acquire(rq2
->lock
); /* Fake it out ;) */
1659 raw_spin_lock(&rq1
->lock
);
1660 raw_spin_lock_nested(&rq2
->lock
, SINGLE_DEPTH_NESTING
);
1662 raw_spin_lock(&rq2
->lock
);
1663 raw_spin_lock_nested(&rq1
->lock
, SINGLE_DEPTH_NESTING
);
1669 * double_rq_unlock - safely unlock two runqueues
1671 * Note this does not restore interrupts like task_rq_unlock,
1672 * you need to do so manually after calling.
1674 static void double_rq_unlock(struct rq
*rq1
, struct rq
*rq2
)
1675 __releases(rq1
->lock
)
1676 __releases(rq2
->lock
)
1678 raw_spin_unlock(&rq1
->lock
);
1680 raw_spin_unlock(&rq2
->lock
);
1682 __release(rq2
->lock
);
1685 #else /* CONFIG_SMP */
1688 * double_rq_lock - safely lock two runqueues
1690 * Note this does not disable interrupts like task_rq_lock,
1691 * you need to do so manually before calling.
1693 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
)
1694 __acquires(rq1
->lock
)
1695 __acquires(rq2
->lock
)
1697 BUG_ON(!irqs_disabled());
1699 raw_spin_lock(&rq1
->lock
);
1700 __acquire(rq2
->lock
); /* Fake it out ;) */
1704 * double_rq_unlock - safely unlock two runqueues
1706 * Note this does not restore interrupts like task_rq_unlock,
1707 * you need to do so manually after calling.
1709 static void double_rq_unlock(struct rq
*rq1
, struct rq
*rq2
)
1710 __releases(rq1
->lock
)
1711 __releases(rq2
->lock
)
1714 raw_spin_unlock(&rq1
->lock
);
1715 __release(rq2
->lock
);
1720 static void calc_load_account_idle(struct rq
*this_rq
);
1721 static void update_sysctl(void);
1722 static int get_update_sysctl_factor(void);
1723 static void update_cpu_load(struct rq
*this_rq
);
1725 static inline void __set_task_cpu(struct task_struct
*p
, unsigned int cpu
)
1727 set_task_rq(p
, cpu
);
1730 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1731 * successfuly executed on another CPU. We must ensure that updates of
1732 * per-task data have been completed by this moment.
1735 task_thread_info(p
)->cpu
= cpu
;
1739 static const struct sched_class rt_sched_class
;
1741 #define sched_class_highest (&stop_sched_class)
1742 #define for_each_class(class) \
1743 for (class = sched_class_highest; class; class = class->next)
1745 #include "sched_stats.h"
1747 static void inc_nr_running(struct rq
*rq
)
1752 static void dec_nr_running(struct rq
*rq
)
1757 static void set_load_weight(struct task_struct
*p
)
1760 * SCHED_IDLE tasks get minimal weight:
1762 if (p
->policy
== SCHED_IDLE
) {
1763 p
->se
.load
.weight
= WEIGHT_IDLEPRIO
;
1764 p
->se
.load
.inv_weight
= WMULT_IDLEPRIO
;
1768 p
->se
.load
.weight
= prio_to_weight
[p
->static_prio
- MAX_RT_PRIO
];
1769 p
->se
.load
.inv_weight
= prio_to_wmult
[p
->static_prio
- MAX_RT_PRIO
];
1772 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
1774 update_rq_clock(rq
);
1775 sched_info_queued(p
);
1776 p
->sched_class
->enqueue_task(rq
, p
, flags
);
1780 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
1782 update_rq_clock(rq
);
1783 sched_info_dequeued(p
);
1784 p
->sched_class
->dequeue_task(rq
, p
, flags
);
1789 * activate_task - move a task to the runqueue.
1791 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
1793 if (task_contributes_to_load(p
))
1794 rq
->nr_uninterruptible
--;
1796 enqueue_task(rq
, p
, flags
);
1801 * deactivate_task - remove a task from the runqueue.
1803 static void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
1805 if (task_contributes_to_load(p
))
1806 rq
->nr_uninterruptible
++;
1808 dequeue_task(rq
, p
, flags
);
1812 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
1815 * There are no locks covering percpu hardirq/softirq time.
1816 * They are only modified in account_system_vtime, on corresponding CPU
1817 * with interrupts disabled. So, writes are safe.
1818 * They are read and saved off onto struct rq in update_rq_clock().
1819 * This may result in other CPU reading this CPU's irq time and can
1820 * race with irq/account_system_vtime on this CPU. We would either get old
1821 * or new value with a side effect of accounting a slice of irq time to wrong
1822 * task when irq is in progress while we read rq->clock. That is a worthy
1823 * compromise in place of having locks on each irq in account_system_time.
1825 static DEFINE_PER_CPU(u64
, cpu_hardirq_time
);
1826 static DEFINE_PER_CPU(u64
, cpu_softirq_time
);
1828 static DEFINE_PER_CPU(u64
, irq_start_time
);
1829 static int sched_clock_irqtime
;
1831 void enable_sched_clock_irqtime(void)
1833 sched_clock_irqtime
= 1;
1836 void disable_sched_clock_irqtime(void)
1838 sched_clock_irqtime
= 0;
1841 #ifndef CONFIG_64BIT
1842 static DEFINE_PER_CPU(seqcount_t
, irq_time_seq
);
1844 static inline void irq_time_write_begin(void)
1846 __this_cpu_inc(irq_time_seq
.sequence
);
1850 static inline void irq_time_write_end(void)
1853 __this_cpu_inc(irq_time_seq
.sequence
);
1856 static inline u64
irq_time_read(int cpu
)
1862 seq
= read_seqcount_begin(&per_cpu(irq_time_seq
, cpu
));
1863 irq_time
= per_cpu(cpu_softirq_time
, cpu
) +
1864 per_cpu(cpu_hardirq_time
, cpu
);
1865 } while (read_seqcount_retry(&per_cpu(irq_time_seq
, cpu
), seq
));
1869 #else /* CONFIG_64BIT */
1870 static inline void irq_time_write_begin(void)
1874 static inline void irq_time_write_end(void)
1878 static inline u64
irq_time_read(int cpu
)
1880 return per_cpu(cpu_softirq_time
, cpu
) + per_cpu(cpu_hardirq_time
, cpu
);
1882 #endif /* CONFIG_64BIT */
1885 * Called before incrementing preempt_count on {soft,}irq_enter
1886 * and before decrementing preempt_count on {soft,}irq_exit.
1888 void account_system_vtime(struct task_struct
*curr
)
1890 unsigned long flags
;
1894 if (!sched_clock_irqtime
)
1897 local_irq_save(flags
);
1899 cpu
= smp_processor_id();
1900 delta
= sched_clock_cpu(cpu
) - __this_cpu_read(irq_start_time
);
1901 __this_cpu_add(irq_start_time
, delta
);
1903 irq_time_write_begin();
1905 * We do not account for softirq time from ksoftirqd here.
1906 * We want to continue accounting softirq time to ksoftirqd thread
1907 * in that case, so as not to confuse scheduler with a special task
1908 * that do not consume any time, but still wants to run.
1910 if (hardirq_count())
1911 __this_cpu_add(cpu_hardirq_time
, delta
);
1912 else if (in_serving_softirq() && curr
!= this_cpu_ksoftirqd())
1913 __this_cpu_add(cpu_softirq_time
, delta
);
1915 irq_time_write_end();
1916 local_irq_restore(flags
);
1918 EXPORT_SYMBOL_GPL(account_system_vtime
);
1920 static void update_rq_clock_task(struct rq
*rq
, s64 delta
)
1924 irq_delta
= irq_time_read(cpu_of(rq
)) - rq
->prev_irq_time
;
1927 * Since irq_time is only updated on {soft,}irq_exit, we might run into
1928 * this case when a previous update_rq_clock() happened inside a
1929 * {soft,}irq region.
1931 * When this happens, we stop ->clock_task and only update the
1932 * prev_irq_time stamp to account for the part that fit, so that a next
1933 * update will consume the rest. This ensures ->clock_task is
1936 * It does however cause some slight miss-attribution of {soft,}irq
1937 * time, a more accurate solution would be to update the irq_time using
1938 * the current rq->clock timestamp, except that would require using
1941 if (irq_delta
> delta
)
1944 rq
->prev_irq_time
+= irq_delta
;
1946 rq
->clock_task
+= delta
;
1948 if (irq_delta
&& sched_feat(NONIRQ_POWER
))
1949 sched_rt_avg_update(rq
, irq_delta
);
1952 static int irqtime_account_hi_update(void)
1954 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
1955 unsigned long flags
;
1959 local_irq_save(flags
);
1960 latest_ns
= this_cpu_read(cpu_hardirq_time
);
1961 if (cputime64_gt(nsecs_to_cputime64(latest_ns
), cpustat
->irq
))
1963 local_irq_restore(flags
);
1967 static int irqtime_account_si_update(void)
1969 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
1970 unsigned long flags
;
1974 local_irq_save(flags
);
1975 latest_ns
= this_cpu_read(cpu_softirq_time
);
1976 if (cputime64_gt(nsecs_to_cputime64(latest_ns
), cpustat
->softirq
))
1978 local_irq_restore(flags
);
1982 #else /* CONFIG_IRQ_TIME_ACCOUNTING */
1984 #define sched_clock_irqtime (0)
1986 static void update_rq_clock_task(struct rq
*rq
, s64 delta
)
1988 rq
->clock_task
+= delta
;
1991 #endif /* CONFIG_IRQ_TIME_ACCOUNTING */
1993 #include "sched_idletask.c"
1994 #include "sched_fair.c"
1995 #include "sched_rt.c"
1996 #include "sched_autogroup.c"
1997 #include "sched_stoptask.c"
1998 #ifdef CONFIG_SCHED_DEBUG
1999 # include "sched_debug.c"
2002 void sched_set_stop_task(int cpu
, struct task_struct
*stop
)
2004 struct sched_param param
= { .sched_priority
= MAX_RT_PRIO
- 1 };
2005 struct task_struct
*old_stop
= cpu_rq(cpu
)->stop
;
2009 * Make it appear like a SCHED_FIFO task, its something
2010 * userspace knows about and won't get confused about.
2012 * Also, it will make PI more or less work without too
2013 * much confusion -- but then, stop work should not
2014 * rely on PI working anyway.
2016 sched_setscheduler_nocheck(stop
, SCHED_FIFO
, ¶m
);
2018 stop
->sched_class
= &stop_sched_class
;
2021 cpu_rq(cpu
)->stop
= stop
;
2025 * Reset it back to a normal scheduling class so that
2026 * it can die in pieces.
2028 old_stop
->sched_class
= &rt_sched_class
;
2033 * __normal_prio - return the priority that is based on the static prio
2035 static inline int __normal_prio(struct task_struct
*p
)
2037 return p
->static_prio
;
2041 * Calculate the expected normal priority: i.e. priority
2042 * without taking RT-inheritance into account. Might be
2043 * boosted by interactivity modifiers. Changes upon fork,
2044 * setprio syscalls, and whenever the interactivity
2045 * estimator recalculates.
2047 static inline int normal_prio(struct task_struct
*p
)
2051 if (task_has_rt_policy(p
))
2052 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
2054 prio
= __normal_prio(p
);
2059 * Calculate the current priority, i.e. the priority
2060 * taken into account by the scheduler. This value might
2061 * be boosted by RT tasks, or might be boosted by
2062 * interactivity modifiers. Will be RT if the task got
2063 * RT-boosted. If not then it returns p->normal_prio.
2065 static int effective_prio(struct task_struct
*p
)
2067 p
->normal_prio
= normal_prio(p
);
2069 * If we are RT tasks or we were boosted to RT priority,
2070 * keep the priority unchanged. Otherwise, update priority
2071 * to the normal priority:
2073 if (!rt_prio(p
->prio
))
2074 return p
->normal_prio
;
2079 * task_curr - is this task currently executing on a CPU?
2080 * @p: the task in question.
2082 inline int task_curr(const struct task_struct
*p
)
2084 return cpu_curr(task_cpu(p
)) == p
;
2087 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
2088 const struct sched_class
*prev_class
,
2091 if (prev_class
!= p
->sched_class
) {
2092 if (prev_class
->switched_from
)
2093 prev_class
->switched_from(rq
, p
);
2094 p
->sched_class
->switched_to(rq
, p
);
2095 } else if (oldprio
!= p
->prio
)
2096 p
->sched_class
->prio_changed(rq
, p
, oldprio
);
2099 static void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int flags
)
2101 const struct sched_class
*class;
2103 if (p
->sched_class
== rq
->curr
->sched_class
) {
2104 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
, flags
);
2106 for_each_class(class) {
2107 if (class == rq
->curr
->sched_class
)
2109 if (class == p
->sched_class
) {
2110 resched_task(rq
->curr
);
2117 * A queue event has occurred, and we're going to schedule. In
2118 * this case, we can save a useless back to back clock update.
2120 if (rq
->curr
->se
.on_rq
&& test_tsk_need_resched(rq
->curr
))
2121 rq
->skip_clock_update
= 1;
2126 * Is this task likely cache-hot:
2129 task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
)
2133 if (p
->sched_class
!= &fair_sched_class
)
2136 if (unlikely(p
->policy
== SCHED_IDLE
))
2140 * Buddy candidates are cache hot:
2142 if (sched_feat(CACHE_HOT_BUDDY
) && this_rq()->nr_running
&&
2143 (&p
->se
== cfs_rq_of(&p
->se
)->next
||
2144 &p
->se
== cfs_rq_of(&p
->se
)->last
))
2147 if (sysctl_sched_migration_cost
== -1)
2149 if (sysctl_sched_migration_cost
== 0)
2152 delta
= now
- p
->se
.exec_start
;
2154 return delta
< (s64
)sysctl_sched_migration_cost
;
2157 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
2159 #ifdef CONFIG_SCHED_DEBUG
2161 * We should never call set_task_cpu() on a blocked task,
2162 * ttwu() will sort out the placement.
2164 WARN_ON_ONCE(p
->state
!= TASK_RUNNING
&& p
->state
!= TASK_WAKING
&&
2165 !(task_thread_info(p
)->preempt_count
& PREEMPT_ACTIVE
));
2168 trace_sched_migrate_task(p
, new_cpu
);
2170 if (task_cpu(p
) != new_cpu
) {
2171 p
->se
.nr_migrations
++;
2172 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS
, 1, 1, NULL
, 0);
2175 __set_task_cpu(p
, new_cpu
);
2178 struct migration_arg
{
2179 struct task_struct
*task
;
2183 static int migration_cpu_stop(void *data
);
2186 * The task's runqueue lock must be held.
2187 * Returns true if you have to wait for migration thread.
2189 static bool migrate_task(struct task_struct
*p
, struct rq
*rq
)
2192 * If the task is not on a runqueue (and not running), then
2193 * the next wake-up will properly place the task.
2195 return p
->se
.on_rq
|| task_running(rq
, p
);
2199 * wait_task_inactive - wait for a thread to unschedule.
2201 * If @match_state is nonzero, it's the @p->state value just checked and
2202 * not expected to change. If it changes, i.e. @p might have woken up,
2203 * then return zero. When we succeed in waiting for @p to be off its CPU,
2204 * we return a positive number (its total switch count). If a second call
2205 * a short while later returns the same number, the caller can be sure that
2206 * @p has remained unscheduled the whole time.
2208 * The caller must ensure that the task *will* unschedule sometime soon,
2209 * else this function might spin for a *long* time. This function can't
2210 * be called with interrupts off, or it may introduce deadlock with
2211 * smp_call_function() if an IPI is sent by the same process we are
2212 * waiting to become inactive.
2214 unsigned long wait_task_inactive(struct task_struct
*p
, long match_state
)
2216 unsigned long flags
;
2223 * We do the initial early heuristics without holding
2224 * any task-queue locks at all. We'll only try to get
2225 * the runqueue lock when things look like they will
2231 * If the task is actively running on another CPU
2232 * still, just relax and busy-wait without holding
2235 * NOTE! Since we don't hold any locks, it's not
2236 * even sure that "rq" stays as the right runqueue!
2237 * But we don't care, since "task_running()" will
2238 * return false if the runqueue has changed and p
2239 * is actually now running somewhere else!
2241 while (task_running(rq
, p
)) {
2242 if (match_state
&& unlikely(p
->state
!= match_state
))
2248 * Ok, time to look more closely! We need the rq
2249 * lock now, to be *sure*. If we're wrong, we'll
2250 * just go back and repeat.
2252 rq
= task_rq_lock(p
, &flags
);
2253 trace_sched_wait_task(p
);
2254 running
= task_running(rq
, p
);
2255 on_rq
= p
->se
.on_rq
;
2257 if (!match_state
|| p
->state
== match_state
)
2258 ncsw
= p
->nvcsw
| LONG_MIN
; /* sets MSB */
2259 task_rq_unlock(rq
, &flags
);
2262 * If it changed from the expected state, bail out now.
2264 if (unlikely(!ncsw
))
2268 * Was it really running after all now that we
2269 * checked with the proper locks actually held?
2271 * Oops. Go back and try again..
2273 if (unlikely(running
)) {
2279 * It's not enough that it's not actively running,
2280 * it must be off the runqueue _entirely_, and not
2283 * So if it was still runnable (but just not actively
2284 * running right now), it's preempted, and we should
2285 * yield - it could be a while.
2287 if (unlikely(on_rq
)) {
2288 ktime_t to
= ktime_set(0, NSEC_PER_SEC
/HZ
);
2290 set_current_state(TASK_UNINTERRUPTIBLE
);
2291 schedule_hrtimeout(&to
, HRTIMER_MODE_REL
);
2296 * Ahh, all good. It wasn't running, and it wasn't
2297 * runnable, which means that it will never become
2298 * running in the future either. We're all done!
2307 * kick_process - kick a running thread to enter/exit the kernel
2308 * @p: the to-be-kicked thread
2310 * Cause a process which is running on another CPU to enter
2311 * kernel-mode, without any delay. (to get signals handled.)
2313 * NOTE: this function doesn't have to take the runqueue lock,
2314 * because all it wants to ensure is that the remote task enters
2315 * the kernel. If the IPI races and the task has been migrated
2316 * to another CPU then no harm is done and the purpose has been
2319 void kick_process(struct task_struct
*p
)
2325 if ((cpu
!= smp_processor_id()) && task_curr(p
))
2326 smp_send_reschedule(cpu
);
2329 EXPORT_SYMBOL_GPL(kick_process
);
2330 #endif /* CONFIG_SMP */
2334 * ->cpus_allowed is protected by either TASK_WAKING or rq->lock held.
2336 static int select_fallback_rq(int cpu
, struct task_struct
*p
)
2339 const struct cpumask
*nodemask
= cpumask_of_node(cpu_to_node(cpu
));
2341 /* Look for allowed, online CPU in same node. */
2342 for_each_cpu_and(dest_cpu
, nodemask
, cpu_active_mask
)
2343 if (cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
2346 /* Any allowed, online CPU? */
2347 dest_cpu
= cpumask_any_and(&p
->cpus_allowed
, cpu_active_mask
);
2348 if (dest_cpu
< nr_cpu_ids
)
2351 /* No more Mr. Nice Guy. */
2352 dest_cpu
= cpuset_cpus_allowed_fallback(p
);
2354 * Don't tell them about moving exiting tasks or
2355 * kernel threads (both mm NULL), since they never
2358 if (p
->mm
&& printk_ratelimit()) {
2359 printk(KERN_INFO
"process %d (%s) no longer affine to cpu%d\n",
2360 task_pid_nr(p
), p
->comm
, cpu
);
2367 * The caller (fork, wakeup) owns TASK_WAKING, ->cpus_allowed is stable.
2370 int select_task_rq(struct rq
*rq
, struct task_struct
*p
, int sd_flags
, int wake_flags
)
2372 int cpu
= p
->sched_class
->select_task_rq(rq
, p
, sd_flags
, wake_flags
);
2375 * In order not to call set_task_cpu() on a blocking task we need
2376 * to rely on ttwu() to place the task on a valid ->cpus_allowed
2379 * Since this is common to all placement strategies, this lives here.
2381 * [ this allows ->select_task() to simply return task_cpu(p) and
2382 * not worry about this generic constraint ]
2384 if (unlikely(!cpumask_test_cpu(cpu
, &p
->cpus_allowed
) ||
2386 cpu
= select_fallback_rq(task_cpu(p
), p
);
2391 static void update_avg(u64
*avg
, u64 sample
)
2393 s64 diff
= sample
- *avg
;
2398 static inline void ttwu_activate(struct task_struct
*p
, struct rq
*rq
,
2399 bool is_sync
, bool is_migrate
, bool is_local
,
2400 unsigned long en_flags
)
2402 schedstat_inc(p
, se
.statistics
.nr_wakeups
);
2404 schedstat_inc(p
, se
.statistics
.nr_wakeups_sync
);
2406 schedstat_inc(p
, se
.statistics
.nr_wakeups_migrate
);
2408 schedstat_inc(p
, se
.statistics
.nr_wakeups_local
);
2410 schedstat_inc(p
, se
.statistics
.nr_wakeups_remote
);
2412 activate_task(rq
, p
, en_flags
);
2415 static inline void ttwu_post_activation(struct task_struct
*p
, struct rq
*rq
,
2416 int wake_flags
, bool success
)
2418 trace_sched_wakeup(p
, success
);
2419 check_preempt_curr(rq
, p
, wake_flags
);
2421 p
->state
= TASK_RUNNING
;
2423 if (p
->sched_class
->task_woken
)
2424 p
->sched_class
->task_woken(rq
, p
);
2426 if (unlikely(rq
->idle_stamp
)) {
2427 u64 delta
= rq
->clock
- rq
->idle_stamp
;
2428 u64 max
= 2*sysctl_sched_migration_cost
;
2433 update_avg(&rq
->avg_idle
, delta
);
2437 /* if a worker is waking up, notify workqueue */
2438 if ((p
->flags
& PF_WQ_WORKER
) && success
)
2439 wq_worker_waking_up(p
, cpu_of(rq
));
2443 * try_to_wake_up - wake up a thread
2444 * @p: the thread to be awakened
2445 * @state: the mask of task states that can be woken
2446 * @wake_flags: wake modifier flags (WF_*)
2448 * Put it on the run-queue if it's not already there. The "current"
2449 * thread is always on the run-queue (except when the actual
2450 * re-schedule is in progress), and as such you're allowed to do
2451 * the simpler "current->state = TASK_RUNNING" to mark yourself
2452 * runnable without the overhead of this.
2454 * Returns %true if @p was woken up, %false if it was already running
2455 * or @state didn't match @p's state.
2457 static int try_to_wake_up(struct task_struct
*p
, unsigned int state
,
2460 int cpu
, orig_cpu
, this_cpu
, success
= 0;
2461 unsigned long flags
;
2462 unsigned long en_flags
= ENQUEUE_WAKEUP
;
2465 this_cpu
= get_cpu();
2468 rq
= task_rq_lock(p
, &flags
);
2469 if (!(p
->state
& state
))
2479 if (unlikely(task_running(rq
, p
)))
2483 * In order to handle concurrent wakeups and release the rq->lock
2484 * we put the task in TASK_WAKING state.
2486 * First fix up the nr_uninterruptible count:
2488 if (task_contributes_to_load(p
)) {
2489 if (likely(cpu_online(orig_cpu
)))
2490 rq
->nr_uninterruptible
--;
2492 this_rq()->nr_uninterruptible
--;
2494 p
->state
= TASK_WAKING
;
2496 if (p
->sched_class
->task_waking
) {
2497 p
->sched_class
->task_waking(rq
, p
);
2498 en_flags
|= ENQUEUE_WAKING
;
2501 cpu
= select_task_rq(rq
, p
, SD_BALANCE_WAKE
, wake_flags
);
2502 if (cpu
!= orig_cpu
)
2503 set_task_cpu(p
, cpu
);
2504 __task_rq_unlock(rq
);
2507 raw_spin_lock(&rq
->lock
);
2510 * We migrated the task without holding either rq->lock, however
2511 * since the task is not on the task list itself, nobody else
2512 * will try and migrate the task, hence the rq should match the
2513 * cpu we just moved it to.
2515 WARN_ON(task_cpu(p
) != cpu
);
2516 WARN_ON(p
->state
!= TASK_WAKING
);
2518 #ifdef CONFIG_SCHEDSTATS
2519 schedstat_inc(rq
, ttwu_count
);
2520 if (cpu
== this_cpu
)
2521 schedstat_inc(rq
, ttwu_local
);
2523 struct sched_domain
*sd
;
2524 for_each_domain(this_cpu
, sd
) {
2525 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
2526 schedstat_inc(sd
, ttwu_wake_remote
);
2531 #endif /* CONFIG_SCHEDSTATS */
2534 #endif /* CONFIG_SMP */
2535 ttwu_activate(p
, rq
, wake_flags
& WF_SYNC
, orig_cpu
!= cpu
,
2536 cpu
== this_cpu
, en_flags
);
2539 ttwu_post_activation(p
, rq
, wake_flags
, success
);
2541 task_rq_unlock(rq
, &flags
);
2548 * try_to_wake_up_local - try to wake up a local task with rq lock held
2549 * @p: the thread to be awakened
2551 * Put @p on the run-queue if it's not already there. The caller must
2552 * ensure that this_rq() is locked, @p is bound to this_rq() and not
2553 * the current task. this_rq() stays locked over invocation.
2555 static void try_to_wake_up_local(struct task_struct
*p
)
2557 struct rq
*rq
= task_rq(p
);
2558 bool success
= false;
2560 BUG_ON(rq
!= this_rq());
2561 BUG_ON(p
== current
);
2562 lockdep_assert_held(&rq
->lock
);
2564 if (!(p
->state
& TASK_NORMAL
))
2568 if (likely(!task_running(rq
, p
))) {
2569 schedstat_inc(rq
, ttwu_count
);
2570 schedstat_inc(rq
, ttwu_local
);
2572 ttwu_activate(p
, rq
, false, false, true, ENQUEUE_WAKEUP
);
2575 ttwu_post_activation(p
, rq
, 0, success
);
2579 * wake_up_process - Wake up a specific process
2580 * @p: The process to be woken up.
2582 * Attempt to wake up the nominated process and move it to the set of runnable
2583 * processes. Returns 1 if the process was woken up, 0 if it was already
2586 * It may be assumed that this function implies a write memory barrier before
2587 * changing the task state if and only if any tasks are woken up.
2589 int wake_up_process(struct task_struct
*p
)
2591 return try_to_wake_up(p
, TASK_ALL
, 0);
2593 EXPORT_SYMBOL(wake_up_process
);
2595 int wake_up_state(struct task_struct
*p
, unsigned int state
)
2597 return try_to_wake_up(p
, state
, 0);
2601 * Perform scheduler related setup for a newly forked process p.
2602 * p is forked by current.
2604 * __sched_fork() is basic setup used by init_idle() too:
2606 static void __sched_fork(struct task_struct
*p
)
2608 p
->se
.exec_start
= 0;
2609 p
->se
.sum_exec_runtime
= 0;
2610 p
->se
.prev_sum_exec_runtime
= 0;
2611 p
->se
.nr_migrations
= 0;
2614 #ifdef CONFIG_SCHEDSTATS
2615 memset(&p
->se
.statistics
, 0, sizeof(p
->se
.statistics
));
2618 INIT_LIST_HEAD(&p
->rt
.run_list
);
2620 INIT_LIST_HEAD(&p
->se
.group_node
);
2622 #ifdef CONFIG_PREEMPT_NOTIFIERS
2623 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
2628 * fork()/clone()-time setup:
2630 void sched_fork(struct task_struct
*p
, int clone_flags
)
2632 int cpu
= get_cpu();
2636 * We mark the process as running here. This guarantees that
2637 * nobody will actually run it, and a signal or other external
2638 * event cannot wake it up and insert it on the runqueue either.
2640 p
->state
= TASK_RUNNING
;
2643 * Revert to default priority/policy on fork if requested.
2645 if (unlikely(p
->sched_reset_on_fork
)) {
2646 if (p
->policy
== SCHED_FIFO
|| p
->policy
== SCHED_RR
) {
2647 p
->policy
= SCHED_NORMAL
;
2648 p
->normal_prio
= p
->static_prio
;
2651 if (PRIO_TO_NICE(p
->static_prio
) < 0) {
2652 p
->static_prio
= NICE_TO_PRIO(0);
2653 p
->normal_prio
= p
->static_prio
;
2658 * We don't need the reset flag anymore after the fork. It has
2659 * fulfilled its duty:
2661 p
->sched_reset_on_fork
= 0;
2665 * Make sure we do not leak PI boosting priority to the child.
2667 p
->prio
= current
->normal_prio
;
2669 if (!rt_prio(p
->prio
))
2670 p
->sched_class
= &fair_sched_class
;
2672 if (p
->sched_class
->task_fork
)
2673 p
->sched_class
->task_fork(p
);
2676 * The child is not yet in the pid-hash so no cgroup attach races,
2677 * and the cgroup is pinned to this child due to cgroup_fork()
2678 * is ran before sched_fork().
2680 * Silence PROVE_RCU.
2683 set_task_cpu(p
, cpu
);
2686 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2687 if (likely(sched_info_on()))
2688 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
2690 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
2693 #ifdef CONFIG_PREEMPT
2694 /* Want to start with kernel preemption disabled. */
2695 task_thread_info(p
)->preempt_count
= 1;
2698 plist_node_init(&p
->pushable_tasks
, MAX_PRIO
);
2705 * wake_up_new_task - wake up a newly created task for the first time.
2707 * This function will do some initial scheduler statistics housekeeping
2708 * that must be done for every newly created context, then puts the task
2709 * on the runqueue and wakes it.
2711 void wake_up_new_task(struct task_struct
*p
, unsigned long clone_flags
)
2713 unsigned long flags
;
2715 int cpu __maybe_unused
= get_cpu();
2718 rq
= task_rq_lock(p
, &flags
);
2719 p
->state
= TASK_WAKING
;
2722 * Fork balancing, do it here and not earlier because:
2723 * - cpus_allowed can change in the fork path
2724 * - any previously selected cpu might disappear through hotplug
2726 * We set TASK_WAKING so that select_task_rq() can drop rq->lock
2727 * without people poking at ->cpus_allowed.
2729 cpu
= select_task_rq(rq
, p
, SD_BALANCE_FORK
, 0);
2730 set_task_cpu(p
, cpu
);
2732 p
->state
= TASK_RUNNING
;
2733 task_rq_unlock(rq
, &flags
);
2736 rq
= task_rq_lock(p
, &flags
);
2737 activate_task(rq
, p
, 0);
2738 trace_sched_wakeup_new(p
, 1);
2739 check_preempt_curr(rq
, p
, WF_FORK
);
2741 if (p
->sched_class
->task_woken
)
2742 p
->sched_class
->task_woken(rq
, p
);
2744 task_rq_unlock(rq
, &flags
);
2748 #ifdef CONFIG_PREEMPT_NOTIFIERS
2751 * preempt_notifier_register - tell me when current is being preempted & rescheduled
2752 * @notifier: notifier struct to register
2754 void preempt_notifier_register(struct preempt_notifier
*notifier
)
2756 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
2758 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
2761 * preempt_notifier_unregister - no longer interested in preemption notifications
2762 * @notifier: notifier struct to unregister
2764 * This is safe to call from within a preemption notifier.
2766 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
2768 hlist_del(¬ifier
->link
);
2770 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
2772 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2774 struct preempt_notifier
*notifier
;
2775 struct hlist_node
*node
;
2777 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2778 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
2782 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2783 struct task_struct
*next
)
2785 struct preempt_notifier
*notifier
;
2786 struct hlist_node
*node
;
2788 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2789 notifier
->ops
->sched_out(notifier
, next
);
2792 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2794 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2799 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2800 struct task_struct
*next
)
2804 #endif /* CONFIG_PREEMPT_NOTIFIERS */
2807 * prepare_task_switch - prepare to switch tasks
2808 * @rq: the runqueue preparing to switch
2809 * @prev: the current task that is being switched out
2810 * @next: the task we are going to switch to.
2812 * This is called with the rq lock held and interrupts off. It must
2813 * be paired with a subsequent finish_task_switch after the context
2816 * prepare_task_switch sets up locking and calls architecture specific
2820 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
2821 struct task_struct
*next
)
2823 sched_info_switch(prev
, next
);
2824 perf_event_task_sched_out(prev
, next
);
2825 fire_sched_out_preempt_notifiers(prev
, next
);
2826 prepare_lock_switch(rq
, next
);
2827 prepare_arch_switch(next
);
2828 trace_sched_switch(prev
, next
);
2832 * finish_task_switch - clean up after a task-switch
2833 * @rq: runqueue associated with task-switch
2834 * @prev: the thread we just switched away from.
2836 * finish_task_switch must be called after the context switch, paired
2837 * with a prepare_task_switch call before the context switch.
2838 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2839 * and do any other architecture-specific cleanup actions.
2841 * Note that we may have delayed dropping an mm in context_switch(). If
2842 * so, we finish that here outside of the runqueue lock. (Doing it
2843 * with the lock held can cause deadlocks; see schedule() for
2846 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
2847 __releases(rq
->lock
)
2849 struct mm_struct
*mm
= rq
->prev_mm
;
2855 * A task struct has one reference for the use as "current".
2856 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2857 * schedule one last time. The schedule call will never return, and
2858 * the scheduled task must drop that reference.
2859 * The test for TASK_DEAD must occur while the runqueue locks are
2860 * still held, otherwise prev could be scheduled on another cpu, die
2861 * there before we look at prev->state, and then the reference would
2863 * Manfred Spraul <manfred@colorfullife.com>
2865 prev_state
= prev
->state
;
2866 finish_arch_switch(prev
);
2867 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
2868 local_irq_disable();
2869 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
2870 perf_event_task_sched_in(current
);
2871 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
2873 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
2874 finish_lock_switch(rq
, prev
);
2876 fire_sched_in_preempt_notifiers(current
);
2879 if (unlikely(prev_state
== TASK_DEAD
)) {
2881 * Remove function-return probe instances associated with this
2882 * task and put them back on the free list.
2884 kprobe_flush_task(prev
);
2885 put_task_struct(prev
);
2891 /* assumes rq->lock is held */
2892 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*prev
)
2894 if (prev
->sched_class
->pre_schedule
)
2895 prev
->sched_class
->pre_schedule(rq
, prev
);
2898 /* rq->lock is NOT held, but preemption is disabled */
2899 static inline void post_schedule(struct rq
*rq
)
2901 if (rq
->post_schedule
) {
2902 unsigned long flags
;
2904 raw_spin_lock_irqsave(&rq
->lock
, flags
);
2905 if (rq
->curr
->sched_class
->post_schedule
)
2906 rq
->curr
->sched_class
->post_schedule(rq
);
2907 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
2909 rq
->post_schedule
= 0;
2915 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*p
)
2919 static inline void post_schedule(struct rq
*rq
)
2926 * schedule_tail - first thing a freshly forked thread must call.
2927 * @prev: the thread we just switched away from.
2929 asmlinkage
void schedule_tail(struct task_struct
*prev
)
2930 __releases(rq
->lock
)
2932 struct rq
*rq
= this_rq();
2934 finish_task_switch(rq
, prev
);
2937 * FIXME: do we need to worry about rq being invalidated by the
2942 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2943 /* In this case, finish_task_switch does not reenable preemption */
2946 if (current
->set_child_tid
)
2947 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2951 * context_switch - switch to the new MM and the new
2952 * thread's register state.
2955 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2956 struct task_struct
*next
)
2958 struct mm_struct
*mm
, *oldmm
;
2960 prepare_task_switch(rq
, prev
, next
);
2963 oldmm
= prev
->active_mm
;
2965 * For paravirt, this is coupled with an exit in switch_to to
2966 * combine the page table reload and the switch backend into
2969 arch_start_context_switch(prev
);
2972 next
->active_mm
= oldmm
;
2973 atomic_inc(&oldmm
->mm_count
);
2974 enter_lazy_tlb(oldmm
, next
);
2976 switch_mm(oldmm
, mm
, next
);
2979 prev
->active_mm
= NULL
;
2980 rq
->prev_mm
= oldmm
;
2983 * Since the runqueue lock will be released by the next
2984 * task (which is an invalid locking op but in the case
2985 * of the scheduler it's an obvious special-case), so we
2986 * do an early lockdep release here:
2988 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2989 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2992 /* Here we just switch the register state and the stack. */
2993 switch_to(prev
, next
, prev
);
2997 * this_rq must be evaluated again because prev may have moved
2998 * CPUs since it called schedule(), thus the 'rq' on its stack
2999 * frame will be invalid.
3001 finish_task_switch(this_rq(), prev
);
3005 * nr_running, nr_uninterruptible and nr_context_switches:
3007 * externally visible scheduler statistics: current number of runnable
3008 * threads, current number of uninterruptible-sleeping threads, total
3009 * number of context switches performed since bootup.
3011 unsigned long nr_running(void)
3013 unsigned long i
, sum
= 0;
3015 for_each_online_cpu(i
)
3016 sum
+= cpu_rq(i
)->nr_running
;
3021 unsigned long nr_uninterruptible(void)
3023 unsigned long i
, sum
= 0;
3025 for_each_possible_cpu(i
)
3026 sum
+= cpu_rq(i
)->nr_uninterruptible
;
3029 * Since we read the counters lockless, it might be slightly
3030 * inaccurate. Do not allow it to go below zero though:
3032 if (unlikely((long)sum
< 0))
3038 unsigned long long nr_context_switches(void)
3041 unsigned long long sum
= 0;
3043 for_each_possible_cpu(i
)
3044 sum
+= cpu_rq(i
)->nr_switches
;
3049 unsigned long nr_iowait(void)
3051 unsigned long i
, sum
= 0;
3053 for_each_possible_cpu(i
)
3054 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
3059 unsigned long nr_iowait_cpu(int cpu
)
3061 struct rq
*this = cpu_rq(cpu
);
3062 return atomic_read(&this->nr_iowait
);
3065 unsigned long this_cpu_load(void)
3067 struct rq
*this = this_rq();
3068 return this->cpu_load
[0];
3072 /* Variables and functions for calc_load */
3073 static atomic_long_t calc_load_tasks
;
3074 static unsigned long calc_load_update
;
3075 unsigned long avenrun
[3];
3076 EXPORT_SYMBOL(avenrun
);
3078 static long calc_load_fold_active(struct rq
*this_rq
)
3080 long nr_active
, delta
= 0;
3082 nr_active
= this_rq
->nr_running
;
3083 nr_active
+= (long) this_rq
->nr_uninterruptible
;
3085 if (nr_active
!= this_rq
->calc_load_active
) {
3086 delta
= nr_active
- this_rq
->calc_load_active
;
3087 this_rq
->calc_load_active
= nr_active
;
3093 static unsigned long
3094 calc_load(unsigned long load
, unsigned long exp
, unsigned long active
)
3097 load
+= active
* (FIXED_1
- exp
);
3098 load
+= 1UL << (FSHIFT
- 1);
3099 return load
>> FSHIFT
;
3104 * For NO_HZ we delay the active fold to the next LOAD_FREQ update.
3106 * When making the ILB scale, we should try to pull this in as well.
3108 static atomic_long_t calc_load_tasks_idle
;
3110 static void calc_load_account_idle(struct rq
*this_rq
)
3114 delta
= calc_load_fold_active(this_rq
);
3116 atomic_long_add(delta
, &calc_load_tasks_idle
);
3119 static long calc_load_fold_idle(void)
3124 * Its got a race, we don't care...
3126 if (atomic_long_read(&calc_load_tasks_idle
))
3127 delta
= atomic_long_xchg(&calc_load_tasks_idle
, 0);
3133 * fixed_power_int - compute: x^n, in O(log n) time
3135 * @x: base of the power
3136 * @frac_bits: fractional bits of @x
3137 * @n: power to raise @x to.
3139 * By exploiting the relation between the definition of the natural power
3140 * function: x^n := x*x*...*x (x multiplied by itself for n times), and
3141 * the binary encoding of numbers used by computers: n := \Sum n_i * 2^i,
3142 * (where: n_i \elem {0, 1}, the binary vector representing n),
3143 * we find: x^n := x^(\Sum n_i * 2^i) := \Prod x^(n_i * 2^i), which is
3144 * of course trivially computable in O(log_2 n), the length of our binary
3147 static unsigned long
3148 fixed_power_int(unsigned long x
, unsigned int frac_bits
, unsigned int n
)
3150 unsigned long result
= 1UL << frac_bits
;
3155 result
+= 1UL << (frac_bits
- 1);
3156 result
>>= frac_bits
;
3162 x
+= 1UL << (frac_bits
- 1);
3170 * a1 = a0 * e + a * (1 - e)
3172 * a2 = a1 * e + a * (1 - e)
3173 * = (a0 * e + a * (1 - e)) * e + a * (1 - e)
3174 * = a0 * e^2 + a * (1 - e) * (1 + e)
3176 * a3 = a2 * e + a * (1 - e)
3177 * = (a0 * e^2 + a * (1 - e) * (1 + e)) * e + a * (1 - e)
3178 * = a0 * e^3 + a * (1 - e) * (1 + e + e^2)
3182 * an = a0 * e^n + a * (1 - e) * (1 + e + ... + e^n-1) [1]
3183 * = a0 * e^n + a * (1 - e) * (1 - e^n)/(1 - e)
3184 * = a0 * e^n + a * (1 - e^n)
3186 * [1] application of the geometric series:
3189 * S_n := \Sum x^i = -------------
3192 static unsigned long
3193 calc_load_n(unsigned long load
, unsigned long exp
,
3194 unsigned long active
, unsigned int n
)
3197 return calc_load(load
, fixed_power_int(exp
, FSHIFT
, n
), active
);
3201 * NO_HZ can leave us missing all per-cpu ticks calling
3202 * calc_load_account_active(), but since an idle CPU folds its delta into
3203 * calc_load_tasks_idle per calc_load_account_idle(), all we need to do is fold
3204 * in the pending idle delta if our idle period crossed a load cycle boundary.
3206 * Once we've updated the global active value, we need to apply the exponential
3207 * weights adjusted to the number of cycles missed.
3209 static void calc_global_nohz(unsigned long ticks
)
3211 long delta
, active
, n
;
3213 if (time_before(jiffies
, calc_load_update
))
3217 * If we crossed a calc_load_update boundary, make sure to fold
3218 * any pending idle changes, the respective CPUs might have
3219 * missed the tick driven calc_load_account_active() update
3222 delta
= calc_load_fold_idle();
3224 atomic_long_add(delta
, &calc_load_tasks
);
3227 * If we were idle for multiple load cycles, apply them.
3229 if (ticks
>= LOAD_FREQ
) {
3230 n
= ticks
/ LOAD_FREQ
;
3232 active
= atomic_long_read(&calc_load_tasks
);
3233 active
= active
> 0 ? active
* FIXED_1
: 0;
3235 avenrun
[0] = calc_load_n(avenrun
[0], EXP_1
, active
, n
);
3236 avenrun
[1] = calc_load_n(avenrun
[1], EXP_5
, active
, n
);
3237 avenrun
[2] = calc_load_n(avenrun
[2], EXP_15
, active
, n
);
3239 calc_load_update
+= n
* LOAD_FREQ
;
3243 * Its possible the remainder of the above division also crosses
3244 * a LOAD_FREQ period, the regular check in calc_global_load()
3245 * which comes after this will take care of that.
3247 * Consider us being 11 ticks before a cycle completion, and us
3248 * sleeping for 4*LOAD_FREQ + 22 ticks, then the above code will
3249 * age us 4 cycles, and the test in calc_global_load() will
3250 * pick up the final one.
3254 static void calc_load_account_idle(struct rq
*this_rq
)
3258 static inline long calc_load_fold_idle(void)
3263 static void calc_global_nohz(unsigned long ticks
)
3269 * get_avenrun - get the load average array
3270 * @loads: pointer to dest load array
3271 * @offset: offset to add
3272 * @shift: shift count to shift the result left
3274 * These values are estimates at best, so no need for locking.
3276 void get_avenrun(unsigned long *loads
, unsigned long offset
, int shift
)
3278 loads
[0] = (avenrun
[0] + offset
) << shift
;
3279 loads
[1] = (avenrun
[1] + offset
) << shift
;
3280 loads
[2] = (avenrun
[2] + offset
) << shift
;
3284 * calc_load - update the avenrun load estimates 10 ticks after the
3285 * CPUs have updated calc_load_tasks.
3287 void calc_global_load(unsigned long ticks
)
3291 calc_global_nohz(ticks
);
3293 if (time_before(jiffies
, calc_load_update
+ 10))
3296 active
= atomic_long_read(&calc_load_tasks
);
3297 active
= active
> 0 ? active
* FIXED_1
: 0;
3299 avenrun
[0] = calc_load(avenrun
[0], EXP_1
, active
);
3300 avenrun
[1] = calc_load(avenrun
[1], EXP_5
, active
);
3301 avenrun
[2] = calc_load(avenrun
[2], EXP_15
, active
);
3303 calc_load_update
+= LOAD_FREQ
;
3307 * Called from update_cpu_load() to periodically update this CPU's
3310 static void calc_load_account_active(struct rq
*this_rq
)
3314 if (time_before(jiffies
, this_rq
->calc_load_update
))
3317 delta
= calc_load_fold_active(this_rq
);
3318 delta
+= calc_load_fold_idle();
3320 atomic_long_add(delta
, &calc_load_tasks
);
3322 this_rq
->calc_load_update
+= LOAD_FREQ
;
3326 * The exact cpuload at various idx values, calculated at every tick would be
3327 * load = (2^idx - 1) / 2^idx * load + 1 / 2^idx * cur_load
3329 * If a cpu misses updates for n-1 ticks (as it was idle) and update gets called
3330 * on nth tick when cpu may be busy, then we have:
3331 * load = ((2^idx - 1) / 2^idx)^(n-1) * load
3332 * load = (2^idx - 1) / 2^idx) * load + 1 / 2^idx * cur_load
3334 * decay_load_missed() below does efficient calculation of
3335 * load = ((2^idx - 1) / 2^idx)^(n-1) * load
3336 * avoiding 0..n-1 loop doing load = ((2^idx - 1) / 2^idx) * load
3338 * The calculation is approximated on a 128 point scale.
3339 * degrade_zero_ticks is the number of ticks after which load at any
3340 * particular idx is approximated to be zero.
3341 * degrade_factor is a precomputed table, a row for each load idx.
3342 * Each column corresponds to degradation factor for a power of two ticks,
3343 * based on 128 point scale.
3345 * row 2, col 3 (=12) says that the degradation at load idx 2 after
3346 * 8 ticks is 12/128 (which is an approximation of exact factor 3^8/4^8).
3348 * With this power of 2 load factors, we can degrade the load n times
3349 * by looking at 1 bits in n and doing as many mult/shift instead of
3350 * n mult/shifts needed by the exact degradation.
3352 #define DEGRADE_SHIFT 7
3353 static const unsigned char
3354 degrade_zero_ticks
[CPU_LOAD_IDX_MAX
] = {0, 8, 32, 64, 128};
3355 static const unsigned char
3356 degrade_factor
[CPU_LOAD_IDX_MAX
][DEGRADE_SHIFT
+ 1] = {
3357 {0, 0, 0, 0, 0, 0, 0, 0},
3358 {64, 32, 8, 0, 0, 0, 0, 0},
3359 {96, 72, 40, 12, 1, 0, 0},
3360 {112, 98, 75, 43, 15, 1, 0},
3361 {120, 112, 98, 76, 45, 16, 2} };
3364 * Update cpu_load for any missed ticks, due to tickless idle. The backlog
3365 * would be when CPU is idle and so we just decay the old load without
3366 * adding any new load.
3368 static unsigned long
3369 decay_load_missed(unsigned long load
, unsigned long missed_updates
, int idx
)
3373 if (!missed_updates
)
3376 if (missed_updates
>= degrade_zero_ticks
[idx
])
3380 return load
>> missed_updates
;
3382 while (missed_updates
) {
3383 if (missed_updates
% 2)
3384 load
= (load
* degrade_factor
[idx
][j
]) >> DEGRADE_SHIFT
;
3386 missed_updates
>>= 1;
3393 * Update rq->cpu_load[] statistics. This function is usually called every
3394 * scheduler tick (TICK_NSEC). With tickless idle this will not be called
3395 * every tick. We fix it up based on jiffies.
3397 static void update_cpu_load(struct rq
*this_rq
)
3399 unsigned long this_load
= this_rq
->load
.weight
;
3400 unsigned long curr_jiffies
= jiffies
;
3401 unsigned long pending_updates
;
3404 this_rq
->nr_load_updates
++;
3406 /* Avoid repeated calls on same jiffy, when moving in and out of idle */
3407 if (curr_jiffies
== this_rq
->last_load_update_tick
)
3410 pending_updates
= curr_jiffies
- this_rq
->last_load_update_tick
;
3411 this_rq
->last_load_update_tick
= curr_jiffies
;
3413 /* Update our load: */
3414 this_rq
->cpu_load
[0] = this_load
; /* Fasttrack for idx 0 */
3415 for (i
= 1, scale
= 2; i
< CPU_LOAD_IDX_MAX
; i
++, scale
+= scale
) {
3416 unsigned long old_load
, new_load
;
3418 /* scale is effectively 1 << i now, and >> i divides by scale */
3420 old_load
= this_rq
->cpu_load
[i
];
3421 old_load
= decay_load_missed(old_load
, pending_updates
- 1, i
);
3422 new_load
= this_load
;
3424 * Round up the averaging division if load is increasing. This
3425 * prevents us from getting stuck on 9 if the load is 10, for
3428 if (new_load
> old_load
)
3429 new_load
+= scale
- 1;
3431 this_rq
->cpu_load
[i
] = (old_load
* (scale
- 1) + new_load
) >> i
;
3434 sched_avg_update(this_rq
);
3437 static void update_cpu_load_active(struct rq
*this_rq
)
3439 update_cpu_load(this_rq
);
3441 calc_load_account_active(this_rq
);
3447 * sched_exec - execve() is a valuable balancing opportunity, because at
3448 * this point the task has the smallest effective memory and cache footprint.
3450 void sched_exec(void)
3452 struct task_struct
*p
= current
;
3453 unsigned long flags
;
3457 rq
= task_rq_lock(p
, &flags
);
3458 dest_cpu
= p
->sched_class
->select_task_rq(rq
, p
, SD_BALANCE_EXEC
, 0);
3459 if (dest_cpu
== smp_processor_id())
3463 * select_task_rq() can race against ->cpus_allowed
3465 if (cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
) &&
3466 likely(cpu_active(dest_cpu
)) && migrate_task(p
, rq
)) {
3467 struct migration_arg arg
= { p
, dest_cpu
};
3469 task_rq_unlock(rq
, &flags
);
3470 stop_one_cpu(cpu_of(rq
), migration_cpu_stop
, &arg
);
3474 task_rq_unlock(rq
, &flags
);
3479 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
3481 EXPORT_PER_CPU_SYMBOL(kstat
);
3484 * Return any ns on the sched_clock that have not yet been accounted in
3485 * @p in case that task is currently running.
3487 * Called with task_rq_lock() held on @rq.
3489 static u64
do_task_delta_exec(struct task_struct
*p
, struct rq
*rq
)
3493 if (task_current(rq
, p
)) {
3494 update_rq_clock(rq
);
3495 ns
= rq
->clock_task
- p
->se
.exec_start
;
3503 unsigned long long task_delta_exec(struct task_struct
*p
)
3505 unsigned long flags
;
3509 rq
= task_rq_lock(p
, &flags
);
3510 ns
= do_task_delta_exec(p
, rq
);
3511 task_rq_unlock(rq
, &flags
);
3517 * Return accounted runtime for the task.
3518 * In case the task is currently running, return the runtime plus current's
3519 * pending runtime that have not been accounted yet.
3521 unsigned long long task_sched_runtime(struct task_struct
*p
)
3523 unsigned long flags
;
3527 rq
= task_rq_lock(p
, &flags
);
3528 ns
= p
->se
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
3529 task_rq_unlock(rq
, &flags
);
3535 * Return sum_exec_runtime for the thread group.
3536 * In case the task is currently running, return the sum plus current's
3537 * pending runtime that have not been accounted yet.
3539 * Note that the thread group might have other running tasks as well,
3540 * so the return value not includes other pending runtime that other
3541 * running tasks might have.
3543 unsigned long long thread_group_sched_runtime(struct task_struct
*p
)
3545 struct task_cputime totals
;
3546 unsigned long flags
;
3550 rq
= task_rq_lock(p
, &flags
);
3551 thread_group_cputime(p
, &totals
);
3552 ns
= totals
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
3553 task_rq_unlock(rq
, &flags
);
3559 * Account user cpu time to a process.
3560 * @p: the process that the cpu time gets accounted to
3561 * @cputime: the cpu time spent in user space since the last update
3562 * @cputime_scaled: cputime scaled by cpu frequency
3564 void account_user_time(struct task_struct
*p
, cputime_t cputime
,
3565 cputime_t cputime_scaled
)
3567 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3570 /* Add user time to process. */
3571 p
->utime
= cputime_add(p
->utime
, cputime
);
3572 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
3573 account_group_user_time(p
, cputime
);
3575 /* Add user time to cpustat. */
3576 tmp
= cputime_to_cputime64(cputime
);
3577 if (TASK_NICE(p
) > 0)
3578 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
3580 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
3582 cpuacct_update_stats(p
, CPUACCT_STAT_USER
, cputime
);
3583 /* Account for user time used */
3584 acct_update_integrals(p
);
3588 * Account guest cpu time to a process.
3589 * @p: the process that the cpu time gets accounted to
3590 * @cputime: the cpu time spent in virtual machine since the last update
3591 * @cputime_scaled: cputime scaled by cpu frequency
3593 static void account_guest_time(struct task_struct
*p
, cputime_t cputime
,
3594 cputime_t cputime_scaled
)
3597 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3599 tmp
= cputime_to_cputime64(cputime
);
3601 /* Add guest time to process. */
3602 p
->utime
= cputime_add(p
->utime
, cputime
);
3603 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
3604 account_group_user_time(p
, cputime
);
3605 p
->gtime
= cputime_add(p
->gtime
, cputime
);
3607 /* Add guest time to cpustat. */
3608 if (TASK_NICE(p
) > 0) {
3609 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
3610 cpustat
->guest_nice
= cputime64_add(cpustat
->guest_nice
, tmp
);
3612 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
3613 cpustat
->guest
= cputime64_add(cpustat
->guest
, tmp
);
3618 * Account system cpu time to a process and desired cpustat field
3619 * @p: the process that the cpu time gets accounted to
3620 * @cputime: the cpu time spent in kernel space since the last update
3621 * @cputime_scaled: cputime scaled by cpu frequency
3622 * @target_cputime64: pointer to cpustat field that has to be updated
3625 void __account_system_time(struct task_struct
*p
, cputime_t cputime
,
3626 cputime_t cputime_scaled
, cputime64_t
*target_cputime64
)
3628 cputime64_t tmp
= cputime_to_cputime64(cputime
);
3630 /* Add system time to process. */
3631 p
->stime
= cputime_add(p
->stime
, cputime
);
3632 p
->stimescaled
= cputime_add(p
->stimescaled
, cputime_scaled
);
3633 account_group_system_time(p
, cputime
);
3635 /* Add system time to cpustat. */
3636 *target_cputime64
= cputime64_add(*target_cputime64
, tmp
);
3637 cpuacct_update_stats(p
, CPUACCT_STAT_SYSTEM
, cputime
);
3639 /* Account for system time used */
3640 acct_update_integrals(p
);
3644 * Account system cpu time to a process.
3645 * @p: the process that the cpu time gets accounted to
3646 * @hardirq_offset: the offset to subtract from hardirq_count()
3647 * @cputime: the cpu time spent in kernel space since the last update
3648 * @cputime_scaled: cputime scaled by cpu frequency
3650 void account_system_time(struct task_struct
*p
, int hardirq_offset
,
3651 cputime_t cputime
, cputime_t cputime_scaled
)
3653 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3654 cputime64_t
*target_cputime64
;
3656 if ((p
->flags
& PF_VCPU
) && (irq_count() - hardirq_offset
== 0)) {
3657 account_guest_time(p
, cputime
, cputime_scaled
);
3661 if (hardirq_count() - hardirq_offset
)
3662 target_cputime64
= &cpustat
->irq
;
3663 else if (in_serving_softirq())
3664 target_cputime64
= &cpustat
->softirq
;
3666 target_cputime64
= &cpustat
->system
;
3668 __account_system_time(p
, cputime
, cputime_scaled
, target_cputime64
);
3672 * Account for involuntary wait time.
3673 * @cputime: the cpu time spent in involuntary wait
3675 void account_steal_time(cputime_t cputime
)
3677 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3678 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
3680 cpustat
->steal
= cputime64_add(cpustat
->steal
, cputime64
);
3684 * Account for idle time.
3685 * @cputime: the cpu time spent in idle wait
3687 void account_idle_time(cputime_t cputime
)
3689 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3690 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
3691 struct rq
*rq
= this_rq();
3693 if (atomic_read(&rq
->nr_iowait
) > 0)
3694 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, cputime64
);
3696 cpustat
->idle
= cputime64_add(cpustat
->idle
, cputime64
);
3699 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
3701 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
3703 * Account a tick to a process and cpustat
3704 * @p: the process that the cpu time gets accounted to
3705 * @user_tick: is the tick from userspace
3706 * @rq: the pointer to rq
3708 * Tick demultiplexing follows the order
3709 * - pending hardirq update
3710 * - pending softirq update
3714 * - check for guest_time
3715 * - else account as system_time
3717 * Check for hardirq is done both for system and user time as there is
3718 * no timer going off while we are on hardirq and hence we may never get an
3719 * opportunity to update it solely in system time.
3720 * p->stime and friends are only updated on system time and not on irq
3721 * softirq as those do not count in task exec_runtime any more.
3723 static void irqtime_account_process_tick(struct task_struct
*p
, int user_tick
,
3726 cputime_t one_jiffy_scaled
= cputime_to_scaled(cputime_one_jiffy
);
3727 cputime64_t tmp
= cputime_to_cputime64(cputime_one_jiffy
);
3728 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3730 if (irqtime_account_hi_update()) {
3731 cpustat
->irq
= cputime64_add(cpustat
->irq
, tmp
);
3732 } else if (irqtime_account_si_update()) {
3733 cpustat
->softirq
= cputime64_add(cpustat
->softirq
, tmp
);
3734 } else if (this_cpu_ksoftirqd() == p
) {
3736 * ksoftirqd time do not get accounted in cpu_softirq_time.
3737 * So, we have to handle it separately here.
3738 * Also, p->stime needs to be updated for ksoftirqd.
3740 __account_system_time(p
, cputime_one_jiffy
, one_jiffy_scaled
,
3742 } else if (user_tick
) {
3743 account_user_time(p
, cputime_one_jiffy
, one_jiffy_scaled
);
3744 } else if (p
== rq
->idle
) {
3745 account_idle_time(cputime_one_jiffy
);
3746 } else if (p
->flags
& PF_VCPU
) { /* System time or guest time */
3747 account_guest_time(p
, cputime_one_jiffy
, one_jiffy_scaled
);
3749 __account_system_time(p
, cputime_one_jiffy
, one_jiffy_scaled
,
3754 static void irqtime_account_idle_ticks(int ticks
)
3757 struct rq
*rq
= this_rq();
3759 for (i
= 0; i
< ticks
; i
++)
3760 irqtime_account_process_tick(current
, 0, rq
);
3762 #else /* CONFIG_IRQ_TIME_ACCOUNTING */
3763 static void irqtime_account_idle_ticks(int ticks
) {}
3764 static void irqtime_account_process_tick(struct task_struct
*p
, int user_tick
,
3766 #endif /* CONFIG_IRQ_TIME_ACCOUNTING */
3769 * Account a single tick of cpu time.
3770 * @p: the process that the cpu time gets accounted to
3771 * @user_tick: indicates if the tick is a user or a system tick
3773 void account_process_tick(struct task_struct
*p
, int user_tick
)
3775 cputime_t one_jiffy_scaled
= cputime_to_scaled(cputime_one_jiffy
);
3776 struct rq
*rq
= this_rq();
3778 if (sched_clock_irqtime
) {
3779 irqtime_account_process_tick(p
, user_tick
, rq
);
3784 account_user_time(p
, cputime_one_jiffy
, one_jiffy_scaled
);
3785 else if ((p
!= rq
->idle
) || (irq_count() != HARDIRQ_OFFSET
))
3786 account_system_time(p
, HARDIRQ_OFFSET
, cputime_one_jiffy
,
3789 account_idle_time(cputime_one_jiffy
);
3793 * Account multiple ticks of steal time.
3794 * @p: the process from which the cpu time has been stolen
3795 * @ticks: number of stolen ticks
3797 void account_steal_ticks(unsigned long ticks
)
3799 account_steal_time(jiffies_to_cputime(ticks
));
3803 * Account multiple ticks of idle time.
3804 * @ticks: number of stolen ticks
3806 void account_idle_ticks(unsigned long ticks
)
3809 if (sched_clock_irqtime
) {
3810 irqtime_account_idle_ticks(ticks
);
3814 account_idle_time(jiffies_to_cputime(ticks
));
3820 * Use precise platform statistics if available:
3822 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
3823 void task_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
3829 void thread_group_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
3831 struct task_cputime cputime
;
3833 thread_group_cputime(p
, &cputime
);
3835 *ut
= cputime
.utime
;
3836 *st
= cputime
.stime
;
3840 #ifndef nsecs_to_cputime
3841 # define nsecs_to_cputime(__nsecs) nsecs_to_jiffies(__nsecs)
3844 void task_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
3846 cputime_t rtime
, utime
= p
->utime
, total
= cputime_add(utime
, p
->stime
);
3849 * Use CFS's precise accounting:
3851 rtime
= nsecs_to_cputime(p
->se
.sum_exec_runtime
);
3857 do_div(temp
, total
);
3858 utime
= (cputime_t
)temp
;
3863 * Compare with previous values, to keep monotonicity:
3865 p
->prev_utime
= max(p
->prev_utime
, utime
);
3866 p
->prev_stime
= max(p
->prev_stime
, cputime_sub(rtime
, p
->prev_utime
));
3868 *ut
= p
->prev_utime
;
3869 *st
= p
->prev_stime
;
3873 * Must be called with siglock held.
3875 void thread_group_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
3877 struct signal_struct
*sig
= p
->signal
;
3878 struct task_cputime cputime
;
3879 cputime_t rtime
, utime
, total
;
3881 thread_group_cputime(p
, &cputime
);
3883 total
= cputime_add(cputime
.utime
, cputime
.stime
);
3884 rtime
= nsecs_to_cputime(cputime
.sum_exec_runtime
);
3889 temp
*= cputime
.utime
;
3890 do_div(temp
, total
);
3891 utime
= (cputime_t
)temp
;
3895 sig
->prev_utime
= max(sig
->prev_utime
, utime
);
3896 sig
->prev_stime
= max(sig
->prev_stime
,
3897 cputime_sub(rtime
, sig
->prev_utime
));
3899 *ut
= sig
->prev_utime
;
3900 *st
= sig
->prev_stime
;
3905 * This function gets called by the timer code, with HZ frequency.
3906 * We call it with interrupts disabled.
3908 * It also gets called by the fork code, when changing the parent's
3911 void scheduler_tick(void)
3913 int cpu
= smp_processor_id();
3914 struct rq
*rq
= cpu_rq(cpu
);
3915 struct task_struct
*curr
= rq
->curr
;
3919 raw_spin_lock(&rq
->lock
);
3920 update_rq_clock(rq
);
3921 update_cpu_load_active(rq
);
3922 curr
->sched_class
->task_tick(rq
, curr
, 0);
3923 raw_spin_unlock(&rq
->lock
);
3925 perf_event_task_tick();
3928 rq
->idle_at_tick
= idle_cpu(cpu
);
3929 trigger_load_balance(rq
, cpu
);
3933 notrace
unsigned long get_parent_ip(unsigned long addr
)
3935 if (in_lock_functions(addr
)) {
3936 addr
= CALLER_ADDR2
;
3937 if (in_lock_functions(addr
))
3938 addr
= CALLER_ADDR3
;
3943 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
3944 defined(CONFIG_PREEMPT_TRACER))
3946 void __kprobes
add_preempt_count(int val
)
3948 #ifdef CONFIG_DEBUG_PREEMPT
3952 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
3955 preempt_count() += val
;
3956 #ifdef CONFIG_DEBUG_PREEMPT
3958 * Spinlock count overflowing soon?
3960 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
3963 if (preempt_count() == val
)
3964 trace_preempt_off(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
3966 EXPORT_SYMBOL(add_preempt_count
);
3968 void __kprobes
sub_preempt_count(int val
)
3970 #ifdef CONFIG_DEBUG_PREEMPT
3974 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
3977 * Is the spinlock portion underflowing?
3979 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
3980 !(preempt_count() & PREEMPT_MASK
)))
3984 if (preempt_count() == val
)
3985 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
3986 preempt_count() -= val
;
3988 EXPORT_SYMBOL(sub_preempt_count
);
3993 * Print scheduling while atomic bug:
3995 static noinline
void __schedule_bug(struct task_struct
*prev
)
3997 struct pt_regs
*regs
= get_irq_regs();
3999 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
4000 prev
->comm
, prev
->pid
, preempt_count());
4002 debug_show_held_locks(prev
);
4004 if (irqs_disabled())
4005 print_irqtrace_events(prev
);
4014 * Various schedule()-time debugging checks and statistics:
4016 static inline void schedule_debug(struct task_struct
*prev
)
4019 * Test if we are atomic. Since do_exit() needs to call into
4020 * schedule() atomically, we ignore that path for now.
4021 * Otherwise, whine if we are scheduling when we should not be.
4023 if (unlikely(in_atomic_preempt_off() && !prev
->exit_state
))
4024 __schedule_bug(prev
);
4026 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
4028 schedstat_inc(this_rq(), sched_count
);
4029 #ifdef CONFIG_SCHEDSTATS
4030 if (unlikely(prev
->lock_depth
>= 0)) {
4031 schedstat_inc(this_rq(), rq_sched_info
.bkl_count
);
4032 schedstat_inc(prev
, sched_info
.bkl_count
);
4037 static void put_prev_task(struct rq
*rq
, struct task_struct
*prev
)
4040 update_rq_clock(rq
);
4041 prev
->sched_class
->put_prev_task(rq
, prev
);
4045 * Pick up the highest-prio task:
4047 static inline struct task_struct
*
4048 pick_next_task(struct rq
*rq
)
4050 const struct sched_class
*class;
4051 struct task_struct
*p
;
4054 * Optimization: we know that if all tasks are in
4055 * the fair class we can call that function directly:
4057 if (likely(rq
->nr_running
== rq
->cfs
.nr_running
)) {
4058 p
= fair_sched_class
.pick_next_task(rq
);
4063 for_each_class(class) {
4064 p
= class->pick_next_task(rq
);
4069 BUG(); /* the idle class will always have a runnable task */
4073 * schedule() is the main scheduler function.
4075 asmlinkage
void __sched
schedule(void)
4077 struct task_struct
*prev
, *next
;
4078 unsigned long *switch_count
;
4084 cpu
= smp_processor_id();
4086 rcu_note_context_switch(cpu
);
4089 schedule_debug(prev
);
4091 if (sched_feat(HRTICK
))
4094 raw_spin_lock_irq(&rq
->lock
);
4096 switch_count
= &prev
->nivcsw
;
4097 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
4098 if (unlikely(signal_pending_state(prev
->state
, prev
))) {
4099 prev
->state
= TASK_RUNNING
;
4102 * If a worker is going to sleep, notify and
4103 * ask workqueue whether it wants to wake up a
4104 * task to maintain concurrency. If so, wake
4107 if (prev
->flags
& PF_WQ_WORKER
) {
4108 struct task_struct
*to_wakeup
;
4110 to_wakeup
= wq_worker_sleeping(prev
, cpu
);
4112 try_to_wake_up_local(to_wakeup
);
4114 deactivate_task(rq
, prev
, DEQUEUE_SLEEP
);
4116 switch_count
= &prev
->nvcsw
;
4120 * If we are going to sleep and we have plugged IO queued, make
4121 * sure to submit it to avoid deadlocks.
4123 if (prev
->state
!= TASK_RUNNING
&& blk_needs_flush_plug(prev
)) {
4124 raw_spin_unlock(&rq
->lock
);
4125 blk_flush_plug(prev
);
4126 raw_spin_lock(&rq
->lock
);
4129 pre_schedule(rq
, prev
);
4131 if (unlikely(!rq
->nr_running
))
4132 idle_balance(cpu
, rq
);
4134 put_prev_task(rq
, prev
);
4135 next
= pick_next_task(rq
);
4136 clear_tsk_need_resched(prev
);
4137 rq
->skip_clock_update
= 0;
4139 if (likely(prev
!= next
)) {
4144 context_switch(rq
, prev
, next
); /* unlocks the rq */
4146 * The context switch have flipped the stack from under us
4147 * and restored the local variables which were saved when
4148 * this task called schedule() in the past. prev == current
4149 * is still correct, but it can be moved to another cpu/rq.
4151 cpu
= smp_processor_id();
4154 raw_spin_unlock_irq(&rq
->lock
);
4158 preempt_enable_no_resched();
4162 EXPORT_SYMBOL(schedule
);
4164 #ifdef CONFIG_MUTEX_SPIN_ON_OWNER
4166 * Look out! "owner" is an entirely speculative pointer
4167 * access and not reliable.
4169 int mutex_spin_on_owner(struct mutex
*lock
, struct thread_info
*owner
)
4174 if (!sched_feat(OWNER_SPIN
))
4177 #ifdef CONFIG_DEBUG_PAGEALLOC
4179 * Need to access the cpu field knowing that
4180 * DEBUG_PAGEALLOC could have unmapped it if
4181 * the mutex owner just released it and exited.
4183 if (probe_kernel_address(&owner
->cpu
, cpu
))
4190 * Even if the access succeeded (likely case),
4191 * the cpu field may no longer be valid.
4193 if (cpu
>= nr_cpumask_bits
)
4197 * We need to validate that we can do a
4198 * get_cpu() and that we have the percpu area.
4200 if (!cpu_online(cpu
))
4207 * Owner changed, break to re-assess state.
4209 if (lock
->owner
!= owner
) {
4211 * If the lock has switched to a different owner,
4212 * we likely have heavy contention. Return 0 to quit
4213 * optimistic spinning and not contend further:
4221 * Is that owner really running on that cpu?
4223 if (task_thread_info(rq
->curr
) != owner
|| need_resched())
4226 arch_mutex_cpu_relax();
4233 #ifdef CONFIG_PREEMPT
4235 * this is the entry point to schedule() from in-kernel preemption
4236 * off of preempt_enable. Kernel preemptions off return from interrupt
4237 * occur there and call schedule directly.
4239 asmlinkage
void __sched notrace
preempt_schedule(void)
4241 struct thread_info
*ti
= current_thread_info();
4244 * If there is a non-zero preempt_count or interrupts are disabled,
4245 * we do not want to preempt the current task. Just return..
4247 if (likely(ti
->preempt_count
|| irqs_disabled()))
4251 add_preempt_count_notrace(PREEMPT_ACTIVE
);
4253 sub_preempt_count_notrace(PREEMPT_ACTIVE
);
4256 * Check again in case we missed a preemption opportunity
4257 * between schedule and now.
4260 } while (need_resched());
4262 EXPORT_SYMBOL(preempt_schedule
);
4265 * this is the entry point to schedule() from kernel preemption
4266 * off of irq context.
4267 * Note, that this is called and return with irqs disabled. This will
4268 * protect us against recursive calling from irq.
4270 asmlinkage
void __sched
preempt_schedule_irq(void)
4272 struct thread_info
*ti
= current_thread_info();
4274 /* Catch callers which need to be fixed */
4275 BUG_ON(ti
->preempt_count
|| !irqs_disabled());
4278 add_preempt_count(PREEMPT_ACTIVE
);
4281 local_irq_disable();
4282 sub_preempt_count(PREEMPT_ACTIVE
);
4285 * Check again in case we missed a preemption opportunity
4286 * between schedule and now.
4289 } while (need_resched());
4292 #endif /* CONFIG_PREEMPT */
4294 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int wake_flags
,
4297 return try_to_wake_up(curr
->private, mode
, wake_flags
);
4299 EXPORT_SYMBOL(default_wake_function
);
4302 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
4303 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
4304 * number) then we wake all the non-exclusive tasks and one exclusive task.
4306 * There are circumstances in which we can try to wake a task which has already
4307 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
4308 * zero in this (rare) case, and we handle it by continuing to scan the queue.
4310 static void __wake_up_common(wait_queue_head_t
*q
, unsigned int mode
,
4311 int nr_exclusive
, int wake_flags
, void *key
)
4313 wait_queue_t
*curr
, *next
;
4315 list_for_each_entry_safe(curr
, next
, &q
->task_list
, task_list
) {
4316 unsigned flags
= curr
->flags
;
4318 if (curr
->func(curr
, mode
, wake_flags
, key
) &&
4319 (flags
& WQ_FLAG_EXCLUSIVE
) && !--nr_exclusive
)
4325 * __wake_up - wake up threads blocked on a waitqueue.
4327 * @mode: which threads
4328 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4329 * @key: is directly passed to the wakeup function
4331 * It may be assumed that this function implies a write memory barrier before
4332 * changing the task state if and only if any tasks are woken up.
4334 void __wake_up(wait_queue_head_t
*q
, unsigned int mode
,
4335 int nr_exclusive
, void *key
)
4337 unsigned long flags
;
4339 spin_lock_irqsave(&q
->lock
, flags
);
4340 __wake_up_common(q
, mode
, nr_exclusive
, 0, key
);
4341 spin_unlock_irqrestore(&q
->lock
, flags
);
4343 EXPORT_SYMBOL(__wake_up
);
4346 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
4348 void __wake_up_locked(wait_queue_head_t
*q
, unsigned int mode
)
4350 __wake_up_common(q
, mode
, 1, 0, NULL
);
4352 EXPORT_SYMBOL_GPL(__wake_up_locked
);
4354 void __wake_up_locked_key(wait_queue_head_t
*q
, unsigned int mode
, void *key
)
4356 __wake_up_common(q
, mode
, 1, 0, key
);
4358 EXPORT_SYMBOL_GPL(__wake_up_locked_key
);
4361 * __wake_up_sync_key - wake up threads blocked on a waitqueue.
4363 * @mode: which threads
4364 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4365 * @key: opaque value to be passed to wakeup targets
4367 * The sync wakeup differs that the waker knows that it will schedule
4368 * away soon, so while the target thread will be woken up, it will not
4369 * be migrated to another CPU - ie. the two threads are 'synchronized'
4370 * with each other. This can prevent needless bouncing between CPUs.
4372 * On UP it can prevent extra preemption.
4374 * It may be assumed that this function implies a write memory barrier before
4375 * changing the task state if and only if any tasks are woken up.
4377 void __wake_up_sync_key(wait_queue_head_t
*q
, unsigned int mode
,
4378 int nr_exclusive
, void *key
)
4380 unsigned long flags
;
4381 int wake_flags
= WF_SYNC
;
4386 if (unlikely(!nr_exclusive
))
4389 spin_lock_irqsave(&q
->lock
, flags
);
4390 __wake_up_common(q
, mode
, nr_exclusive
, wake_flags
, key
);
4391 spin_unlock_irqrestore(&q
->lock
, flags
);
4393 EXPORT_SYMBOL_GPL(__wake_up_sync_key
);
4396 * __wake_up_sync - see __wake_up_sync_key()
4398 void __wake_up_sync(wait_queue_head_t
*q
, unsigned int mode
, int nr_exclusive
)
4400 __wake_up_sync_key(q
, mode
, nr_exclusive
, NULL
);
4402 EXPORT_SYMBOL_GPL(__wake_up_sync
); /* For internal use only */
4405 * complete: - signals a single thread waiting on this completion
4406 * @x: holds the state of this particular completion
4408 * This will wake up a single thread waiting on this completion. Threads will be
4409 * awakened in the same order in which they were queued.
4411 * See also complete_all(), wait_for_completion() and related routines.
4413 * It may be assumed that this function implies a write memory barrier before
4414 * changing the task state if and only if any tasks are woken up.
4416 void complete(struct completion
*x
)
4418 unsigned long flags
;
4420 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4422 __wake_up_common(&x
->wait
, TASK_NORMAL
, 1, 0, NULL
);
4423 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4425 EXPORT_SYMBOL(complete
);
4428 * complete_all: - signals all threads waiting on this completion
4429 * @x: holds the state of this particular completion
4431 * This will wake up all threads waiting on this particular completion event.
4433 * It may be assumed that this function implies a write memory barrier before
4434 * changing the task state if and only if any tasks are woken up.
4436 void complete_all(struct completion
*x
)
4438 unsigned long flags
;
4440 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4441 x
->done
+= UINT_MAX
/2;
4442 __wake_up_common(&x
->wait
, TASK_NORMAL
, 0, 0, NULL
);
4443 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4445 EXPORT_SYMBOL(complete_all
);
4447 static inline long __sched
4448 do_wait_for_common(struct completion
*x
, long timeout
, int state
)
4451 DECLARE_WAITQUEUE(wait
, current
);
4453 __add_wait_queue_tail_exclusive(&x
->wait
, &wait
);
4455 if (signal_pending_state(state
, current
)) {
4456 timeout
= -ERESTARTSYS
;
4459 __set_current_state(state
);
4460 spin_unlock_irq(&x
->wait
.lock
);
4461 timeout
= schedule_timeout(timeout
);
4462 spin_lock_irq(&x
->wait
.lock
);
4463 } while (!x
->done
&& timeout
);
4464 __remove_wait_queue(&x
->wait
, &wait
);
4469 return timeout
?: 1;
4473 wait_for_common(struct completion
*x
, long timeout
, int state
)
4477 spin_lock_irq(&x
->wait
.lock
);
4478 timeout
= do_wait_for_common(x
, timeout
, state
);
4479 spin_unlock_irq(&x
->wait
.lock
);
4484 * wait_for_completion: - waits for completion of a task
4485 * @x: holds the state of this particular completion
4487 * This waits to be signaled for completion of a specific task. It is NOT
4488 * interruptible and there is no timeout.
4490 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
4491 * and interrupt capability. Also see complete().
4493 void __sched
wait_for_completion(struct completion
*x
)
4495 wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
4497 EXPORT_SYMBOL(wait_for_completion
);
4500 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
4501 * @x: holds the state of this particular completion
4502 * @timeout: timeout value in jiffies
4504 * This waits for either a completion of a specific task to be signaled or for a
4505 * specified timeout to expire. The timeout is in jiffies. It is not
4508 unsigned long __sched
4509 wait_for_completion_timeout(struct completion
*x
, unsigned long timeout
)
4511 return wait_for_common(x
, timeout
, TASK_UNINTERRUPTIBLE
);
4513 EXPORT_SYMBOL(wait_for_completion_timeout
);
4516 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
4517 * @x: holds the state of this particular completion
4519 * This waits for completion of a specific task to be signaled. It is
4522 int __sched
wait_for_completion_interruptible(struct completion
*x
)
4524 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_INTERRUPTIBLE
);
4525 if (t
== -ERESTARTSYS
)
4529 EXPORT_SYMBOL(wait_for_completion_interruptible
);
4532 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
4533 * @x: holds the state of this particular completion
4534 * @timeout: timeout value in jiffies
4536 * This waits for either a completion of a specific task to be signaled or for a
4537 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
4540 wait_for_completion_interruptible_timeout(struct completion
*x
,
4541 unsigned long timeout
)
4543 return wait_for_common(x
, timeout
, TASK_INTERRUPTIBLE
);
4545 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout
);
4548 * wait_for_completion_killable: - waits for completion of a task (killable)
4549 * @x: holds the state of this particular completion
4551 * This waits to be signaled for completion of a specific task. It can be
4552 * interrupted by a kill signal.
4554 int __sched
wait_for_completion_killable(struct completion
*x
)
4556 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_KILLABLE
);
4557 if (t
== -ERESTARTSYS
)
4561 EXPORT_SYMBOL(wait_for_completion_killable
);
4564 * wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable))
4565 * @x: holds the state of this particular completion
4566 * @timeout: timeout value in jiffies
4568 * This waits for either a completion of a specific task to be
4569 * signaled or for a specified timeout to expire. It can be
4570 * interrupted by a kill signal. The timeout is in jiffies.
4573 wait_for_completion_killable_timeout(struct completion
*x
,
4574 unsigned long timeout
)
4576 return wait_for_common(x
, timeout
, TASK_KILLABLE
);
4578 EXPORT_SYMBOL(wait_for_completion_killable_timeout
);
4581 * try_wait_for_completion - try to decrement a completion without blocking
4582 * @x: completion structure
4584 * Returns: 0 if a decrement cannot be done without blocking
4585 * 1 if a decrement succeeded.
4587 * If a completion is being used as a counting completion,
4588 * attempt to decrement the counter without blocking. This
4589 * enables us to avoid waiting if the resource the completion
4590 * is protecting is not available.
4592 bool try_wait_for_completion(struct completion
*x
)
4594 unsigned long flags
;
4597 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4602 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4605 EXPORT_SYMBOL(try_wait_for_completion
);
4608 * completion_done - Test to see if a completion has any waiters
4609 * @x: completion structure
4611 * Returns: 0 if there are waiters (wait_for_completion() in progress)
4612 * 1 if there are no waiters.
4615 bool completion_done(struct completion
*x
)
4617 unsigned long flags
;
4620 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4623 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4626 EXPORT_SYMBOL(completion_done
);
4629 sleep_on_common(wait_queue_head_t
*q
, int state
, long timeout
)
4631 unsigned long flags
;
4634 init_waitqueue_entry(&wait
, current
);
4636 __set_current_state(state
);
4638 spin_lock_irqsave(&q
->lock
, flags
);
4639 __add_wait_queue(q
, &wait
);
4640 spin_unlock(&q
->lock
);
4641 timeout
= schedule_timeout(timeout
);
4642 spin_lock_irq(&q
->lock
);
4643 __remove_wait_queue(q
, &wait
);
4644 spin_unlock_irqrestore(&q
->lock
, flags
);
4649 void __sched
interruptible_sleep_on(wait_queue_head_t
*q
)
4651 sleep_on_common(q
, TASK_INTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
4653 EXPORT_SYMBOL(interruptible_sleep_on
);
4656 interruptible_sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
4658 return sleep_on_common(q
, TASK_INTERRUPTIBLE
, timeout
);
4660 EXPORT_SYMBOL(interruptible_sleep_on_timeout
);
4662 void __sched
sleep_on(wait_queue_head_t
*q
)
4664 sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
4666 EXPORT_SYMBOL(sleep_on
);
4668 long __sched
sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
4670 return sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, timeout
);
4672 EXPORT_SYMBOL(sleep_on_timeout
);
4674 #ifdef CONFIG_RT_MUTEXES
4677 * rt_mutex_setprio - set the current priority of a task
4679 * @prio: prio value (kernel-internal form)
4681 * This function changes the 'effective' priority of a task. It does
4682 * not touch ->normal_prio like __setscheduler().
4684 * Used by the rt_mutex code to implement priority inheritance logic.
4686 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
4688 unsigned long flags
;
4689 int oldprio
, on_rq
, running
;
4691 const struct sched_class
*prev_class
;
4693 BUG_ON(prio
< 0 || prio
> MAX_PRIO
);
4695 rq
= task_rq_lock(p
, &flags
);
4697 trace_sched_pi_setprio(p
, prio
);
4699 prev_class
= p
->sched_class
;
4700 on_rq
= p
->se
.on_rq
;
4701 running
= task_current(rq
, p
);
4703 dequeue_task(rq
, p
, 0);
4705 p
->sched_class
->put_prev_task(rq
, p
);
4708 p
->sched_class
= &rt_sched_class
;
4710 p
->sched_class
= &fair_sched_class
;
4715 p
->sched_class
->set_curr_task(rq
);
4717 enqueue_task(rq
, p
, oldprio
< prio
? ENQUEUE_HEAD
: 0);
4719 check_class_changed(rq
, p
, prev_class
, oldprio
);
4720 task_rq_unlock(rq
, &flags
);
4725 void set_user_nice(struct task_struct
*p
, long nice
)
4727 int old_prio
, delta
, on_rq
;
4728 unsigned long flags
;
4731 if (TASK_NICE(p
) == nice
|| nice
< -20 || nice
> 19)
4734 * We have to be careful, if called from sys_setpriority(),
4735 * the task might be in the middle of scheduling on another CPU.
4737 rq
= task_rq_lock(p
, &flags
);
4739 * The RT priorities are set via sched_setscheduler(), but we still
4740 * allow the 'normal' nice value to be set - but as expected
4741 * it wont have any effect on scheduling until the task is
4742 * SCHED_FIFO/SCHED_RR:
4744 if (task_has_rt_policy(p
)) {
4745 p
->static_prio
= NICE_TO_PRIO(nice
);
4748 on_rq
= p
->se
.on_rq
;
4750 dequeue_task(rq
, p
, 0);
4752 p
->static_prio
= NICE_TO_PRIO(nice
);
4755 p
->prio
= effective_prio(p
);
4756 delta
= p
->prio
- old_prio
;
4759 enqueue_task(rq
, p
, 0);
4761 * If the task increased its priority or is running and
4762 * lowered its priority, then reschedule its CPU:
4764 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
4765 resched_task(rq
->curr
);
4768 task_rq_unlock(rq
, &flags
);
4770 EXPORT_SYMBOL(set_user_nice
);
4773 * can_nice - check if a task can reduce its nice value
4777 int can_nice(const struct task_struct
*p
, const int nice
)
4779 /* convert nice value [19,-20] to rlimit style value [1,40] */
4780 int nice_rlim
= 20 - nice
;
4782 return (nice_rlim
<= task_rlimit(p
, RLIMIT_NICE
) ||
4783 capable(CAP_SYS_NICE
));
4786 #ifdef __ARCH_WANT_SYS_NICE
4789 * sys_nice - change the priority of the current process.
4790 * @increment: priority increment
4792 * sys_setpriority is a more generic, but much slower function that
4793 * does similar things.
4795 SYSCALL_DEFINE1(nice
, int, increment
)
4800 * Setpriority might change our priority at the same moment.
4801 * We don't have to worry. Conceptually one call occurs first
4802 * and we have a single winner.
4804 if (increment
< -40)
4809 nice
= TASK_NICE(current
) + increment
;
4815 if (increment
< 0 && !can_nice(current
, nice
))
4818 retval
= security_task_setnice(current
, nice
);
4822 set_user_nice(current
, nice
);
4829 * task_prio - return the priority value of a given task.
4830 * @p: the task in question.
4832 * This is the priority value as seen by users in /proc.
4833 * RT tasks are offset by -200. Normal tasks are centered
4834 * around 0, value goes from -16 to +15.
4836 int task_prio(const struct task_struct
*p
)
4838 return p
->prio
- MAX_RT_PRIO
;
4842 * task_nice - return the nice value of a given task.
4843 * @p: the task in question.
4845 int task_nice(const struct task_struct
*p
)
4847 return TASK_NICE(p
);
4849 EXPORT_SYMBOL(task_nice
);
4852 * idle_cpu - is a given cpu idle currently?
4853 * @cpu: the processor in question.
4855 int idle_cpu(int cpu
)
4857 return cpu_curr(cpu
) == cpu_rq(cpu
)->idle
;
4861 * idle_task - return the idle task for a given cpu.
4862 * @cpu: the processor in question.
4864 struct task_struct
*idle_task(int cpu
)
4866 return cpu_rq(cpu
)->idle
;
4870 * find_process_by_pid - find a process with a matching PID value.
4871 * @pid: the pid in question.
4873 static struct task_struct
*find_process_by_pid(pid_t pid
)
4875 return pid
? find_task_by_vpid(pid
) : current
;
4878 /* Actually do priority change: must hold rq lock. */
4880 __setscheduler(struct rq
*rq
, struct task_struct
*p
, int policy
, int prio
)
4882 BUG_ON(p
->se
.on_rq
);
4885 p
->rt_priority
= prio
;
4886 p
->normal_prio
= normal_prio(p
);
4887 /* we are holding p->pi_lock already */
4888 p
->prio
= rt_mutex_getprio(p
);
4889 if (rt_prio(p
->prio
))
4890 p
->sched_class
= &rt_sched_class
;
4892 p
->sched_class
= &fair_sched_class
;
4897 * check the target process has a UID that matches the current process's
4899 static bool check_same_owner(struct task_struct
*p
)
4901 const struct cred
*cred
= current_cred(), *pcred
;
4905 pcred
= __task_cred(p
);
4906 if (cred
->user
->user_ns
== pcred
->user
->user_ns
)
4907 match
= (cred
->euid
== pcred
->euid
||
4908 cred
->euid
== pcred
->uid
);
4915 static int __sched_setscheduler(struct task_struct
*p
, int policy
,
4916 const struct sched_param
*param
, bool user
)
4918 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
4919 unsigned long flags
;
4920 const struct sched_class
*prev_class
;
4924 /* may grab non-irq protected spin_locks */
4925 BUG_ON(in_interrupt());
4927 /* double check policy once rq lock held */
4929 reset_on_fork
= p
->sched_reset_on_fork
;
4930 policy
= oldpolicy
= p
->policy
;
4932 reset_on_fork
= !!(policy
& SCHED_RESET_ON_FORK
);
4933 policy
&= ~SCHED_RESET_ON_FORK
;
4935 if (policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
4936 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
4937 policy
!= SCHED_IDLE
)
4942 * Valid priorities for SCHED_FIFO and SCHED_RR are
4943 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
4944 * SCHED_BATCH and SCHED_IDLE is 0.
4946 if (param
->sched_priority
< 0 ||
4947 (p
->mm
&& param
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
4948 (!p
->mm
&& param
->sched_priority
> MAX_RT_PRIO
-1))
4950 if (rt_policy(policy
) != (param
->sched_priority
!= 0))
4954 * Allow unprivileged RT tasks to decrease priority:
4956 if (user
&& !capable(CAP_SYS_NICE
)) {
4957 if (rt_policy(policy
)) {
4958 unsigned long rlim_rtprio
=
4959 task_rlimit(p
, RLIMIT_RTPRIO
);
4961 /* can't set/change the rt policy */
4962 if (policy
!= p
->policy
&& !rlim_rtprio
)
4965 /* can't increase priority */
4966 if (param
->sched_priority
> p
->rt_priority
&&
4967 param
->sched_priority
> rlim_rtprio
)
4972 * Treat SCHED_IDLE as nice 20. Only allow a switch to
4973 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
4975 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
) {
4976 if (!can_nice(p
, TASK_NICE(p
)))
4980 /* can't change other user's priorities */
4981 if (!check_same_owner(p
))
4984 /* Normal users shall not reset the sched_reset_on_fork flag */
4985 if (p
->sched_reset_on_fork
&& !reset_on_fork
)
4990 retval
= security_task_setscheduler(p
);
4996 * make sure no PI-waiters arrive (or leave) while we are
4997 * changing the priority of the task:
4999 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
5001 * To be able to change p->policy safely, the appropriate
5002 * runqueue lock must be held.
5004 rq
= __task_rq_lock(p
);
5007 * Changing the policy of the stop threads its a very bad idea
5009 if (p
== rq
->stop
) {
5010 __task_rq_unlock(rq
);
5011 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
5016 * If not changing anything there's no need to proceed further:
5018 if (unlikely(policy
== p
->policy
&& (!rt_policy(policy
) ||
5019 param
->sched_priority
== p
->rt_priority
))) {
5021 __task_rq_unlock(rq
);
5022 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
5026 #ifdef CONFIG_RT_GROUP_SCHED
5029 * Do not allow realtime tasks into groups that have no runtime
5032 if (rt_bandwidth_enabled() && rt_policy(policy
) &&
5033 task_group(p
)->rt_bandwidth
.rt_runtime
== 0 &&
5034 !task_group_is_autogroup(task_group(p
))) {
5035 __task_rq_unlock(rq
);
5036 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
5042 /* recheck policy now with rq lock held */
5043 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
5044 policy
= oldpolicy
= -1;
5045 __task_rq_unlock(rq
);
5046 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
5049 on_rq
= p
->se
.on_rq
;
5050 running
= task_current(rq
, p
);
5052 deactivate_task(rq
, p
, 0);
5054 p
->sched_class
->put_prev_task(rq
, p
);
5056 p
->sched_reset_on_fork
= reset_on_fork
;
5059 prev_class
= p
->sched_class
;
5060 __setscheduler(rq
, p
, policy
, param
->sched_priority
);
5063 p
->sched_class
->set_curr_task(rq
);
5065 activate_task(rq
, p
, 0);
5067 check_class_changed(rq
, p
, prev_class
, oldprio
);
5068 __task_rq_unlock(rq
);
5069 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
5071 rt_mutex_adjust_pi(p
);
5077 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
5078 * @p: the task in question.
5079 * @policy: new policy.
5080 * @param: structure containing the new RT priority.
5082 * NOTE that the task may be already dead.
5084 int sched_setscheduler(struct task_struct
*p
, int policy
,
5085 const struct sched_param
*param
)
5087 return __sched_setscheduler(p
, policy
, param
, true);
5089 EXPORT_SYMBOL_GPL(sched_setscheduler
);
5092 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
5093 * @p: the task in question.
5094 * @policy: new policy.
5095 * @param: structure containing the new RT priority.
5097 * Just like sched_setscheduler, only don't bother checking if the
5098 * current context has permission. For example, this is needed in
5099 * stop_machine(): we create temporary high priority worker threads,
5100 * but our caller might not have that capability.
5102 int sched_setscheduler_nocheck(struct task_struct
*p
, int policy
,
5103 const struct sched_param
*param
)
5105 return __sched_setscheduler(p
, policy
, param
, false);
5109 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
5111 struct sched_param lparam
;
5112 struct task_struct
*p
;
5115 if (!param
|| pid
< 0)
5117 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
5122 p
= find_process_by_pid(pid
);
5124 retval
= sched_setscheduler(p
, policy
, &lparam
);
5131 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
5132 * @pid: the pid in question.
5133 * @policy: new policy.
5134 * @param: structure containing the new RT priority.
5136 SYSCALL_DEFINE3(sched_setscheduler
, pid_t
, pid
, int, policy
,
5137 struct sched_param __user
*, param
)
5139 /* negative values for policy are not valid */
5143 return do_sched_setscheduler(pid
, policy
, param
);
5147 * sys_sched_setparam - set/change the RT priority of a thread
5148 * @pid: the pid in question.
5149 * @param: structure containing the new RT priority.
5151 SYSCALL_DEFINE2(sched_setparam
, pid_t
, pid
, struct sched_param __user
*, param
)
5153 return do_sched_setscheduler(pid
, -1, param
);
5157 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
5158 * @pid: the pid in question.
5160 SYSCALL_DEFINE1(sched_getscheduler
, pid_t
, pid
)
5162 struct task_struct
*p
;
5170 p
= find_process_by_pid(pid
);
5172 retval
= security_task_getscheduler(p
);
5175 | (p
->sched_reset_on_fork
? SCHED_RESET_ON_FORK
: 0);
5182 * sys_sched_getparam - get the RT priority of a thread
5183 * @pid: the pid in question.
5184 * @param: structure containing the RT priority.
5186 SYSCALL_DEFINE2(sched_getparam
, pid_t
, pid
, struct sched_param __user
*, param
)
5188 struct sched_param lp
;
5189 struct task_struct
*p
;
5192 if (!param
|| pid
< 0)
5196 p
= find_process_by_pid(pid
);
5201 retval
= security_task_getscheduler(p
);
5205 lp
.sched_priority
= p
->rt_priority
;
5209 * This one might sleep, we cannot do it with a spinlock held ...
5211 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
5220 long sched_setaffinity(pid_t pid
, const struct cpumask
*in_mask
)
5222 cpumask_var_t cpus_allowed
, new_mask
;
5223 struct task_struct
*p
;
5229 p
= find_process_by_pid(pid
);
5236 /* Prevent p going away */
5240 if (!alloc_cpumask_var(&cpus_allowed
, GFP_KERNEL
)) {
5244 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
)) {
5246 goto out_free_cpus_allowed
;
5249 if (!check_same_owner(p
) && !task_ns_capable(p
, CAP_SYS_NICE
))
5252 retval
= security_task_setscheduler(p
);
5256 cpuset_cpus_allowed(p
, cpus_allowed
);
5257 cpumask_and(new_mask
, in_mask
, cpus_allowed
);
5259 retval
= set_cpus_allowed_ptr(p
, new_mask
);
5262 cpuset_cpus_allowed(p
, cpus_allowed
);
5263 if (!cpumask_subset(new_mask
, cpus_allowed
)) {
5265 * We must have raced with a concurrent cpuset
5266 * update. Just reset the cpus_allowed to the
5267 * cpuset's cpus_allowed
5269 cpumask_copy(new_mask
, cpus_allowed
);
5274 free_cpumask_var(new_mask
);
5275 out_free_cpus_allowed
:
5276 free_cpumask_var(cpus_allowed
);
5283 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
5284 struct cpumask
*new_mask
)
5286 if (len
< cpumask_size())
5287 cpumask_clear(new_mask
);
5288 else if (len
> cpumask_size())
5289 len
= cpumask_size();
5291 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
5295 * sys_sched_setaffinity - set the cpu affinity of a process
5296 * @pid: pid of the process
5297 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5298 * @user_mask_ptr: user-space pointer to the new cpu mask
5300 SYSCALL_DEFINE3(sched_setaffinity
, pid_t
, pid
, unsigned int, len
,
5301 unsigned long __user
*, user_mask_ptr
)
5303 cpumask_var_t new_mask
;
5306 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
5309 retval
= get_user_cpu_mask(user_mask_ptr
, len
, new_mask
);
5311 retval
= sched_setaffinity(pid
, new_mask
);
5312 free_cpumask_var(new_mask
);
5316 long sched_getaffinity(pid_t pid
, struct cpumask
*mask
)
5318 struct task_struct
*p
;
5319 unsigned long flags
;
5327 p
= find_process_by_pid(pid
);
5331 retval
= security_task_getscheduler(p
);
5335 rq
= task_rq_lock(p
, &flags
);
5336 cpumask_and(mask
, &p
->cpus_allowed
, cpu_online_mask
);
5337 task_rq_unlock(rq
, &flags
);
5347 * sys_sched_getaffinity - get the cpu affinity of a process
5348 * @pid: pid of the process
5349 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5350 * @user_mask_ptr: user-space pointer to hold the current cpu mask
5352 SYSCALL_DEFINE3(sched_getaffinity
, pid_t
, pid
, unsigned int, len
,
5353 unsigned long __user
*, user_mask_ptr
)
5358 if ((len
* BITS_PER_BYTE
) < nr_cpu_ids
)
5360 if (len
& (sizeof(unsigned long)-1))
5363 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
5366 ret
= sched_getaffinity(pid
, mask
);
5368 size_t retlen
= min_t(size_t, len
, cpumask_size());
5370 if (copy_to_user(user_mask_ptr
, mask
, retlen
))
5375 free_cpumask_var(mask
);
5381 * sys_sched_yield - yield the current processor to other threads.
5383 * This function yields the current CPU to other tasks. If there are no
5384 * other threads running on this CPU then this function will return.
5386 SYSCALL_DEFINE0(sched_yield
)
5388 struct rq
*rq
= this_rq_lock();
5390 schedstat_inc(rq
, yld_count
);
5391 current
->sched_class
->yield_task(rq
);
5394 * Since we are going to call schedule() anyway, there's
5395 * no need to preempt or enable interrupts:
5397 __release(rq
->lock
);
5398 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
5399 do_raw_spin_unlock(&rq
->lock
);
5400 preempt_enable_no_resched();
5407 static inline int should_resched(void)
5409 return need_resched() && !(preempt_count() & PREEMPT_ACTIVE
);
5412 static void __cond_resched(void)
5414 add_preempt_count(PREEMPT_ACTIVE
);
5416 sub_preempt_count(PREEMPT_ACTIVE
);
5419 int __sched
_cond_resched(void)
5421 if (should_resched()) {
5427 EXPORT_SYMBOL(_cond_resched
);
5430 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
5431 * call schedule, and on return reacquire the lock.
5433 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
5434 * operations here to prevent schedule() from being called twice (once via
5435 * spin_unlock(), once by hand).
5437 int __cond_resched_lock(spinlock_t
*lock
)
5439 int resched
= should_resched();
5442 lockdep_assert_held(lock
);
5444 if (spin_needbreak(lock
) || resched
) {
5455 EXPORT_SYMBOL(__cond_resched_lock
);
5457 int __sched
__cond_resched_softirq(void)
5459 BUG_ON(!in_softirq());
5461 if (should_resched()) {
5469 EXPORT_SYMBOL(__cond_resched_softirq
);
5472 * yield - yield the current processor to other threads.
5474 * This is a shortcut for kernel-space yielding - it marks the
5475 * thread runnable and calls sys_sched_yield().
5477 void __sched
yield(void)
5479 set_current_state(TASK_RUNNING
);
5482 EXPORT_SYMBOL(yield
);
5485 * yield_to - yield the current processor to another thread in
5486 * your thread group, or accelerate that thread toward the
5487 * processor it's on.
5489 * @preempt: whether task preemption is allowed or not
5491 * It's the caller's job to ensure that the target task struct
5492 * can't go away on us before we can do any checks.
5494 * Returns true if we indeed boosted the target task.
5496 bool __sched
yield_to(struct task_struct
*p
, bool preempt
)
5498 struct task_struct
*curr
= current
;
5499 struct rq
*rq
, *p_rq
;
5500 unsigned long flags
;
5503 local_irq_save(flags
);
5508 double_rq_lock(rq
, p_rq
);
5509 while (task_rq(p
) != p_rq
) {
5510 double_rq_unlock(rq
, p_rq
);
5514 if (!curr
->sched_class
->yield_to_task
)
5517 if (curr
->sched_class
!= p
->sched_class
)
5520 if (task_running(p_rq
, p
) || p
->state
)
5523 yielded
= curr
->sched_class
->yield_to_task(rq
, p
, preempt
);
5525 schedstat_inc(rq
, yld_count
);
5527 * Make p's CPU reschedule; pick_next_entity takes care of
5530 if (preempt
&& rq
!= p_rq
)
5531 resched_task(p_rq
->curr
);
5535 double_rq_unlock(rq
, p_rq
);
5536 local_irq_restore(flags
);
5543 EXPORT_SYMBOL_GPL(yield_to
);
5546 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
5547 * that process accounting knows that this is a task in IO wait state.
5549 void __sched
io_schedule(void)
5551 struct rq
*rq
= raw_rq();
5553 delayacct_blkio_start();
5554 atomic_inc(&rq
->nr_iowait
);
5555 blk_flush_plug(current
);
5556 current
->in_iowait
= 1;
5558 current
->in_iowait
= 0;
5559 atomic_dec(&rq
->nr_iowait
);
5560 delayacct_blkio_end();
5562 EXPORT_SYMBOL(io_schedule
);
5564 long __sched
io_schedule_timeout(long timeout
)
5566 struct rq
*rq
= raw_rq();
5569 delayacct_blkio_start();
5570 atomic_inc(&rq
->nr_iowait
);
5571 blk_flush_plug(current
);
5572 current
->in_iowait
= 1;
5573 ret
= schedule_timeout(timeout
);
5574 current
->in_iowait
= 0;
5575 atomic_dec(&rq
->nr_iowait
);
5576 delayacct_blkio_end();
5581 * sys_sched_get_priority_max - return maximum RT priority.
5582 * @policy: scheduling class.
5584 * this syscall returns the maximum rt_priority that can be used
5585 * by a given scheduling class.
5587 SYSCALL_DEFINE1(sched_get_priority_max
, int, policy
)
5594 ret
= MAX_USER_RT_PRIO
-1;
5606 * sys_sched_get_priority_min - return minimum RT priority.
5607 * @policy: scheduling class.
5609 * this syscall returns the minimum rt_priority that can be used
5610 * by a given scheduling class.
5612 SYSCALL_DEFINE1(sched_get_priority_min
, int, policy
)
5630 * sys_sched_rr_get_interval - return the default timeslice of a process.
5631 * @pid: pid of the process.
5632 * @interval: userspace pointer to the timeslice value.
5634 * this syscall writes the default timeslice value of a given process
5635 * into the user-space timespec buffer. A value of '0' means infinity.
5637 SYSCALL_DEFINE2(sched_rr_get_interval
, pid_t
, pid
,
5638 struct timespec __user
*, interval
)
5640 struct task_struct
*p
;
5641 unsigned int time_slice
;
5642 unsigned long flags
;
5652 p
= find_process_by_pid(pid
);
5656 retval
= security_task_getscheduler(p
);
5660 rq
= task_rq_lock(p
, &flags
);
5661 time_slice
= p
->sched_class
->get_rr_interval(rq
, p
);
5662 task_rq_unlock(rq
, &flags
);
5665 jiffies_to_timespec(time_slice
, &t
);
5666 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
5674 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
5676 void sched_show_task(struct task_struct
*p
)
5678 unsigned long free
= 0;
5681 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
5682 printk(KERN_INFO
"%-15.15s %c", p
->comm
,
5683 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
5684 #if BITS_PER_LONG == 32
5685 if (state
== TASK_RUNNING
)
5686 printk(KERN_CONT
" running ");
5688 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
5690 if (state
== TASK_RUNNING
)
5691 printk(KERN_CONT
" running task ");
5693 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
5695 #ifdef CONFIG_DEBUG_STACK_USAGE
5696 free
= stack_not_used(p
);
5698 printk(KERN_CONT
"%5lu %5d %6d 0x%08lx\n", free
,
5699 task_pid_nr(p
), task_pid_nr(p
->real_parent
),
5700 (unsigned long)task_thread_info(p
)->flags
);
5702 show_stack(p
, NULL
);
5705 void show_state_filter(unsigned long state_filter
)
5707 struct task_struct
*g
, *p
;
5709 #if BITS_PER_LONG == 32
5711 " task PC stack pid father\n");
5714 " task PC stack pid father\n");
5716 read_lock(&tasklist_lock
);
5717 do_each_thread(g
, p
) {
5719 * reset the NMI-timeout, listing all files on a slow
5720 * console might take a lot of time:
5722 touch_nmi_watchdog();
5723 if (!state_filter
|| (p
->state
& state_filter
))
5725 } while_each_thread(g
, p
);
5727 touch_all_softlockup_watchdogs();
5729 #ifdef CONFIG_SCHED_DEBUG
5730 sysrq_sched_debug_show();
5732 read_unlock(&tasklist_lock
);
5734 * Only show locks if all tasks are dumped:
5737 debug_show_all_locks();
5740 void __cpuinit
init_idle_bootup_task(struct task_struct
*idle
)
5742 idle
->sched_class
= &idle_sched_class
;
5746 * init_idle - set up an idle thread for a given CPU
5747 * @idle: task in question
5748 * @cpu: cpu the idle task belongs to
5750 * NOTE: this function does not set the idle thread's NEED_RESCHED
5751 * flag, to make booting more robust.
5753 void __cpuinit
init_idle(struct task_struct
*idle
, int cpu
)
5755 struct rq
*rq
= cpu_rq(cpu
);
5756 unsigned long flags
;
5758 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5761 idle
->state
= TASK_RUNNING
;
5762 idle
->se
.exec_start
= sched_clock();
5764 cpumask_copy(&idle
->cpus_allowed
, cpumask_of(cpu
));
5766 * We're having a chicken and egg problem, even though we are
5767 * holding rq->lock, the cpu isn't yet set to this cpu so the
5768 * lockdep check in task_group() will fail.
5770 * Similar case to sched_fork(). / Alternatively we could
5771 * use task_rq_lock() here and obtain the other rq->lock.
5776 __set_task_cpu(idle
, cpu
);
5779 rq
->curr
= rq
->idle
= idle
;
5780 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
5783 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5785 /* Set the preempt count _outside_ the spinlocks! */
5786 #if defined(CONFIG_PREEMPT)
5787 task_thread_info(idle
)->preempt_count
= (idle
->lock_depth
>= 0);
5789 task_thread_info(idle
)->preempt_count
= 0;
5792 * The idle tasks have their own, simple scheduling class:
5794 idle
->sched_class
= &idle_sched_class
;
5795 ftrace_graph_init_idle_task(idle
, cpu
);
5799 * In a system that switches off the HZ timer nohz_cpu_mask
5800 * indicates which cpus entered this state. This is used
5801 * in the rcu update to wait only for active cpus. For system
5802 * which do not switch off the HZ timer nohz_cpu_mask should
5803 * always be CPU_BITS_NONE.
5805 cpumask_var_t nohz_cpu_mask
;
5808 * Increase the granularity value when there are more CPUs,
5809 * because with more CPUs the 'effective latency' as visible
5810 * to users decreases. But the relationship is not linear,
5811 * so pick a second-best guess by going with the log2 of the
5814 * This idea comes from the SD scheduler of Con Kolivas:
5816 static int get_update_sysctl_factor(void)
5818 unsigned int cpus
= min_t(int, num_online_cpus(), 8);
5819 unsigned int factor
;
5821 switch (sysctl_sched_tunable_scaling
) {
5822 case SCHED_TUNABLESCALING_NONE
:
5825 case SCHED_TUNABLESCALING_LINEAR
:
5828 case SCHED_TUNABLESCALING_LOG
:
5830 factor
= 1 + ilog2(cpus
);
5837 static void update_sysctl(void)
5839 unsigned int factor
= get_update_sysctl_factor();
5841 #define SET_SYSCTL(name) \
5842 (sysctl_##name = (factor) * normalized_sysctl_##name)
5843 SET_SYSCTL(sched_min_granularity
);
5844 SET_SYSCTL(sched_latency
);
5845 SET_SYSCTL(sched_wakeup_granularity
);
5849 static inline void sched_init_granularity(void)
5856 * This is how migration works:
5858 * 1) we invoke migration_cpu_stop() on the target CPU using
5860 * 2) stopper starts to run (implicitly forcing the migrated thread
5862 * 3) it checks whether the migrated task is still in the wrong runqueue.
5863 * 4) if it's in the wrong runqueue then the migration thread removes
5864 * it and puts it into the right queue.
5865 * 5) stopper completes and stop_one_cpu() returns and the migration
5870 * Change a given task's CPU affinity. Migrate the thread to a
5871 * proper CPU and schedule it away if the CPU it's executing on
5872 * is removed from the allowed bitmask.
5874 * NOTE: the caller must have a valid reference to the task, the
5875 * task must not exit() & deallocate itself prematurely. The
5876 * call is not atomic; no spinlocks may be held.
5878 int set_cpus_allowed_ptr(struct task_struct
*p
, const struct cpumask
*new_mask
)
5880 unsigned long flags
;
5882 unsigned int dest_cpu
;
5886 * Serialize against TASK_WAKING so that ttwu() and wunt() can
5887 * drop the rq->lock and still rely on ->cpus_allowed.
5890 while (task_is_waking(p
))
5892 rq
= task_rq_lock(p
, &flags
);
5893 if (task_is_waking(p
)) {
5894 task_rq_unlock(rq
, &flags
);
5898 if (!cpumask_intersects(new_mask
, cpu_active_mask
)) {
5903 if (unlikely((p
->flags
& PF_THREAD_BOUND
) && p
!= current
&&
5904 !cpumask_equal(&p
->cpus_allowed
, new_mask
))) {
5909 if (p
->sched_class
->set_cpus_allowed
)
5910 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
5912 cpumask_copy(&p
->cpus_allowed
, new_mask
);
5913 p
->rt
.nr_cpus_allowed
= cpumask_weight(new_mask
);
5916 /* Can the task run on the task's current CPU? If so, we're done */
5917 if (cpumask_test_cpu(task_cpu(p
), new_mask
))
5920 dest_cpu
= cpumask_any_and(cpu_active_mask
, new_mask
);
5921 if (migrate_task(p
, rq
)) {
5922 struct migration_arg arg
= { p
, dest_cpu
};
5923 /* Need help from migration thread: drop lock and wait. */
5924 task_rq_unlock(rq
, &flags
);
5925 stop_one_cpu(cpu_of(rq
), migration_cpu_stop
, &arg
);
5926 tlb_migrate_finish(p
->mm
);
5930 task_rq_unlock(rq
, &flags
);
5934 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
5937 * Move (not current) task off this cpu, onto dest cpu. We're doing
5938 * this because either it can't run here any more (set_cpus_allowed()
5939 * away from this CPU, or CPU going down), or because we're
5940 * attempting to rebalance this task on exec (sched_exec).
5942 * So we race with normal scheduler movements, but that's OK, as long
5943 * as the task is no longer on this CPU.
5945 * Returns non-zero if task was successfully migrated.
5947 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
5949 struct rq
*rq_dest
, *rq_src
;
5952 if (unlikely(!cpu_active(dest_cpu
)))
5955 rq_src
= cpu_rq(src_cpu
);
5956 rq_dest
= cpu_rq(dest_cpu
);
5958 double_rq_lock(rq_src
, rq_dest
);
5959 /* Already moved. */
5960 if (task_cpu(p
) != src_cpu
)
5962 /* Affinity changed (again). */
5963 if (!cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
5967 * If we're not on a rq, the next wake-up will ensure we're
5971 deactivate_task(rq_src
, p
, 0);
5972 set_task_cpu(p
, dest_cpu
);
5973 activate_task(rq_dest
, p
, 0);
5974 check_preempt_curr(rq_dest
, p
, 0);
5979 double_rq_unlock(rq_src
, rq_dest
);
5984 * migration_cpu_stop - this will be executed by a highprio stopper thread
5985 * and performs thread migration by bumping thread off CPU then
5986 * 'pushing' onto another runqueue.
5988 static int migration_cpu_stop(void *data
)
5990 struct migration_arg
*arg
= data
;
5993 * The original target cpu might have gone down and we might
5994 * be on another cpu but it doesn't matter.
5996 local_irq_disable();
5997 __migrate_task(arg
->task
, raw_smp_processor_id(), arg
->dest_cpu
);
6002 #ifdef CONFIG_HOTPLUG_CPU
6005 * Ensures that the idle task is using init_mm right before its cpu goes
6008 void idle_task_exit(void)
6010 struct mm_struct
*mm
= current
->active_mm
;
6012 BUG_ON(cpu_online(smp_processor_id()));
6015 switch_mm(mm
, &init_mm
, current
);
6020 * While a dead CPU has no uninterruptible tasks queued at this point,
6021 * it might still have a nonzero ->nr_uninterruptible counter, because
6022 * for performance reasons the counter is not stricly tracking tasks to
6023 * their home CPUs. So we just add the counter to another CPU's counter,
6024 * to keep the global sum constant after CPU-down:
6026 static void migrate_nr_uninterruptible(struct rq
*rq_src
)
6028 struct rq
*rq_dest
= cpu_rq(cpumask_any(cpu_active_mask
));
6030 rq_dest
->nr_uninterruptible
+= rq_src
->nr_uninterruptible
;
6031 rq_src
->nr_uninterruptible
= 0;
6035 * remove the tasks which were accounted by rq from calc_load_tasks.
6037 static void calc_global_load_remove(struct rq
*rq
)
6039 atomic_long_sub(rq
->calc_load_active
, &calc_load_tasks
);
6040 rq
->calc_load_active
= 0;
6044 * Migrate all tasks from the rq, sleeping tasks will be migrated by
6045 * try_to_wake_up()->select_task_rq().
6047 * Called with rq->lock held even though we'er in stop_machine() and
6048 * there's no concurrency possible, we hold the required locks anyway
6049 * because of lock validation efforts.
6051 static void migrate_tasks(unsigned int dead_cpu
)
6053 struct rq
*rq
= cpu_rq(dead_cpu
);
6054 struct task_struct
*next
, *stop
= rq
->stop
;
6058 * Fudge the rq selection such that the below task selection loop
6059 * doesn't get stuck on the currently eligible stop task.
6061 * We're currently inside stop_machine() and the rq is either stuck
6062 * in the stop_machine_cpu_stop() loop, or we're executing this code,
6063 * either way we should never end up calling schedule() until we're
6070 * There's this thread running, bail when that's the only
6073 if (rq
->nr_running
== 1)
6076 next
= pick_next_task(rq
);
6078 next
->sched_class
->put_prev_task(rq
, next
);
6080 /* Find suitable destination for @next, with force if needed. */
6081 dest_cpu
= select_fallback_rq(dead_cpu
, next
);
6082 raw_spin_unlock(&rq
->lock
);
6084 __migrate_task(next
, dead_cpu
, dest_cpu
);
6086 raw_spin_lock(&rq
->lock
);
6092 #endif /* CONFIG_HOTPLUG_CPU */
6094 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
6096 static struct ctl_table sd_ctl_dir
[] = {
6098 .procname
= "sched_domain",
6104 static struct ctl_table sd_ctl_root
[] = {
6106 .procname
= "kernel",
6108 .child
= sd_ctl_dir
,
6113 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
6115 struct ctl_table
*entry
=
6116 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
6121 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
6123 struct ctl_table
*entry
;
6126 * In the intermediate directories, both the child directory and
6127 * procname are dynamically allocated and could fail but the mode
6128 * will always be set. In the lowest directory the names are
6129 * static strings and all have proc handlers.
6131 for (entry
= *tablep
; entry
->mode
; entry
++) {
6133 sd_free_ctl_entry(&entry
->child
);
6134 if (entry
->proc_handler
== NULL
)
6135 kfree(entry
->procname
);
6143 set_table_entry(struct ctl_table
*entry
,
6144 const char *procname
, void *data
, int maxlen
,
6145 mode_t mode
, proc_handler
*proc_handler
)
6147 entry
->procname
= procname
;
6149 entry
->maxlen
= maxlen
;
6151 entry
->proc_handler
= proc_handler
;
6154 static struct ctl_table
*
6155 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
6157 struct ctl_table
*table
= sd_alloc_ctl_entry(13);
6162 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
6163 sizeof(long), 0644, proc_doulongvec_minmax
);
6164 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
6165 sizeof(long), 0644, proc_doulongvec_minmax
);
6166 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
6167 sizeof(int), 0644, proc_dointvec_minmax
);
6168 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
6169 sizeof(int), 0644, proc_dointvec_minmax
);
6170 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
6171 sizeof(int), 0644, proc_dointvec_minmax
);
6172 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
6173 sizeof(int), 0644, proc_dointvec_minmax
);
6174 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
6175 sizeof(int), 0644, proc_dointvec_minmax
);
6176 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
6177 sizeof(int), 0644, proc_dointvec_minmax
);
6178 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
6179 sizeof(int), 0644, proc_dointvec_minmax
);
6180 set_table_entry(&table
[9], "cache_nice_tries",
6181 &sd
->cache_nice_tries
,
6182 sizeof(int), 0644, proc_dointvec_minmax
);
6183 set_table_entry(&table
[10], "flags", &sd
->flags
,
6184 sizeof(int), 0644, proc_dointvec_minmax
);
6185 set_table_entry(&table
[11], "name", sd
->name
,
6186 CORENAME_MAX_SIZE
, 0444, proc_dostring
);
6187 /* &table[12] is terminator */
6192 static ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
6194 struct ctl_table
*entry
, *table
;
6195 struct sched_domain
*sd
;
6196 int domain_num
= 0, i
;
6199 for_each_domain(cpu
, sd
)
6201 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
6206 for_each_domain(cpu
, sd
) {
6207 snprintf(buf
, 32, "domain%d", i
);
6208 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
6210 entry
->child
= sd_alloc_ctl_domain_table(sd
);
6217 static struct ctl_table_header
*sd_sysctl_header
;
6218 static void register_sched_domain_sysctl(void)
6220 int i
, cpu_num
= num_possible_cpus();
6221 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
6224 WARN_ON(sd_ctl_dir
[0].child
);
6225 sd_ctl_dir
[0].child
= entry
;
6230 for_each_possible_cpu(i
) {
6231 snprintf(buf
, 32, "cpu%d", i
);
6232 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
6234 entry
->child
= sd_alloc_ctl_cpu_table(i
);
6238 WARN_ON(sd_sysctl_header
);
6239 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
6242 /* may be called multiple times per register */
6243 static void unregister_sched_domain_sysctl(void)
6245 if (sd_sysctl_header
)
6246 unregister_sysctl_table(sd_sysctl_header
);
6247 sd_sysctl_header
= NULL
;
6248 if (sd_ctl_dir
[0].child
)
6249 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
6252 static void register_sched_domain_sysctl(void)
6255 static void unregister_sched_domain_sysctl(void)
6260 static void set_rq_online(struct rq
*rq
)
6263 const struct sched_class
*class;
6265 cpumask_set_cpu(rq
->cpu
, rq
->rd
->online
);
6268 for_each_class(class) {
6269 if (class->rq_online
)
6270 class->rq_online(rq
);
6275 static void set_rq_offline(struct rq
*rq
)
6278 const struct sched_class
*class;
6280 for_each_class(class) {
6281 if (class->rq_offline
)
6282 class->rq_offline(rq
);
6285 cpumask_clear_cpu(rq
->cpu
, rq
->rd
->online
);
6291 * migration_call - callback that gets triggered when a CPU is added.
6292 * Here we can start up the necessary migration thread for the new CPU.
6294 static int __cpuinit
6295 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
6297 int cpu
= (long)hcpu
;
6298 unsigned long flags
;
6299 struct rq
*rq
= cpu_rq(cpu
);
6301 switch (action
& ~CPU_TASKS_FROZEN
) {
6303 case CPU_UP_PREPARE
:
6304 rq
->calc_load_update
= calc_load_update
;
6308 /* Update our root-domain */
6309 raw_spin_lock_irqsave(&rq
->lock
, flags
);
6311 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
6315 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
6318 #ifdef CONFIG_HOTPLUG_CPU
6320 /* Update our root-domain */
6321 raw_spin_lock_irqsave(&rq
->lock
, flags
);
6323 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
6327 BUG_ON(rq
->nr_running
!= 1); /* the migration thread */
6328 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
6330 migrate_nr_uninterruptible(rq
);
6331 calc_global_load_remove(rq
);
6336 update_max_interval();
6342 * Register at high priority so that task migration (migrate_all_tasks)
6343 * happens before everything else. This has to be lower priority than
6344 * the notifier in the perf_event subsystem, though.
6346 static struct notifier_block __cpuinitdata migration_notifier
= {
6347 .notifier_call
= migration_call
,
6348 .priority
= CPU_PRI_MIGRATION
,
6351 static int __cpuinit
sched_cpu_active(struct notifier_block
*nfb
,
6352 unsigned long action
, void *hcpu
)
6354 switch (action
& ~CPU_TASKS_FROZEN
) {
6356 case CPU_DOWN_FAILED
:
6357 set_cpu_active((long)hcpu
, true);
6364 static int __cpuinit
sched_cpu_inactive(struct notifier_block
*nfb
,
6365 unsigned long action
, void *hcpu
)
6367 switch (action
& ~CPU_TASKS_FROZEN
) {
6368 case CPU_DOWN_PREPARE
:
6369 set_cpu_active((long)hcpu
, false);
6376 static int __init
migration_init(void)
6378 void *cpu
= (void *)(long)smp_processor_id();
6381 /* Initialize migration for the boot CPU */
6382 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
6383 BUG_ON(err
== NOTIFY_BAD
);
6384 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
6385 register_cpu_notifier(&migration_notifier
);
6387 /* Register cpu active notifiers */
6388 cpu_notifier(sched_cpu_active
, CPU_PRI_SCHED_ACTIVE
);
6389 cpu_notifier(sched_cpu_inactive
, CPU_PRI_SCHED_INACTIVE
);
6393 early_initcall(migration_init
);
6398 #ifdef CONFIG_SCHED_DEBUG
6400 static __read_mostly
int sched_domain_debug_enabled
;
6402 static int __init
sched_domain_debug_setup(char *str
)
6404 sched_domain_debug_enabled
= 1;
6408 early_param("sched_debug", sched_domain_debug_setup
);
6410 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
6411 struct cpumask
*groupmask
)
6413 struct sched_group
*group
= sd
->groups
;
6416 cpulist_scnprintf(str
, sizeof(str
), sched_domain_span(sd
));
6417 cpumask_clear(groupmask
);
6419 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
6421 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
6422 printk("does not load-balance\n");
6424 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
6429 printk(KERN_CONT
"span %s level %s\n", str
, sd
->name
);
6431 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
6432 printk(KERN_ERR
"ERROR: domain->span does not contain "
6435 if (!cpumask_test_cpu(cpu
, sched_group_cpus(group
))) {
6436 printk(KERN_ERR
"ERROR: domain->groups does not contain"
6440 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
6444 printk(KERN_ERR
"ERROR: group is NULL\n");
6448 if (!group
->cpu_power
) {
6449 printk(KERN_CONT
"\n");
6450 printk(KERN_ERR
"ERROR: domain->cpu_power not "
6455 if (!cpumask_weight(sched_group_cpus(group
))) {
6456 printk(KERN_CONT
"\n");
6457 printk(KERN_ERR
"ERROR: empty group\n");
6461 if (cpumask_intersects(groupmask
, sched_group_cpus(group
))) {
6462 printk(KERN_CONT
"\n");
6463 printk(KERN_ERR
"ERROR: repeated CPUs\n");
6467 cpumask_or(groupmask
, groupmask
, sched_group_cpus(group
));
6469 cpulist_scnprintf(str
, sizeof(str
), sched_group_cpus(group
));
6471 printk(KERN_CONT
" %s", str
);
6472 if (group
->cpu_power
!= SCHED_LOAD_SCALE
) {
6473 printk(KERN_CONT
" (cpu_power = %d)",
6477 group
= group
->next
;
6478 } while (group
!= sd
->groups
);
6479 printk(KERN_CONT
"\n");
6481 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
6482 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
6485 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
6486 printk(KERN_ERR
"ERROR: parent span is not a superset "
6487 "of domain->span\n");
6491 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
6493 cpumask_var_t groupmask
;
6496 if (!sched_domain_debug_enabled
)
6500 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
6504 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
6506 if (!alloc_cpumask_var(&groupmask
, GFP_KERNEL
)) {
6507 printk(KERN_DEBUG
"Cannot load-balance (out of memory)\n");
6512 if (sched_domain_debug_one(sd
, cpu
, level
, groupmask
))
6519 free_cpumask_var(groupmask
);
6521 #else /* !CONFIG_SCHED_DEBUG */
6522 # define sched_domain_debug(sd, cpu) do { } while (0)
6523 #endif /* CONFIG_SCHED_DEBUG */
6525 static int sd_degenerate(struct sched_domain
*sd
)
6527 if (cpumask_weight(sched_domain_span(sd
)) == 1)
6530 /* Following flags need at least 2 groups */
6531 if (sd
->flags
& (SD_LOAD_BALANCE
|
6532 SD_BALANCE_NEWIDLE
|
6536 SD_SHARE_PKG_RESOURCES
)) {
6537 if (sd
->groups
!= sd
->groups
->next
)
6541 /* Following flags don't use groups */
6542 if (sd
->flags
& (SD_WAKE_AFFINE
))
6549 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
6551 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
6553 if (sd_degenerate(parent
))
6556 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
6559 /* Flags needing groups don't count if only 1 group in parent */
6560 if (parent
->groups
== parent
->groups
->next
) {
6561 pflags
&= ~(SD_LOAD_BALANCE
|
6562 SD_BALANCE_NEWIDLE
|
6566 SD_SHARE_PKG_RESOURCES
);
6567 if (nr_node_ids
== 1)
6568 pflags
&= ~SD_SERIALIZE
;
6570 if (~cflags
& pflags
)
6576 static void free_rootdomain(struct rcu_head
*rcu
)
6578 struct root_domain
*rd
= container_of(rcu
, struct root_domain
, rcu
);
6580 cpupri_cleanup(&rd
->cpupri
);
6581 free_cpumask_var(rd
->rto_mask
);
6582 free_cpumask_var(rd
->online
);
6583 free_cpumask_var(rd
->span
);
6587 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
6589 struct root_domain
*old_rd
= NULL
;
6590 unsigned long flags
;
6592 raw_spin_lock_irqsave(&rq
->lock
, flags
);
6597 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
6600 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
6603 * If we dont want to free the old_rt yet then
6604 * set old_rd to NULL to skip the freeing later
6607 if (!atomic_dec_and_test(&old_rd
->refcount
))
6611 atomic_inc(&rd
->refcount
);
6614 cpumask_set_cpu(rq
->cpu
, rd
->span
);
6615 if (cpumask_test_cpu(rq
->cpu
, cpu_active_mask
))
6618 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
6621 call_rcu_sched(&old_rd
->rcu
, free_rootdomain
);
6624 static int init_rootdomain(struct root_domain
*rd
)
6626 memset(rd
, 0, sizeof(*rd
));
6628 if (!alloc_cpumask_var(&rd
->span
, GFP_KERNEL
))
6630 if (!alloc_cpumask_var(&rd
->online
, GFP_KERNEL
))
6632 if (!alloc_cpumask_var(&rd
->rto_mask
, GFP_KERNEL
))
6635 if (cpupri_init(&rd
->cpupri
) != 0)
6640 free_cpumask_var(rd
->rto_mask
);
6642 free_cpumask_var(rd
->online
);
6644 free_cpumask_var(rd
->span
);
6649 static void init_defrootdomain(void)
6651 init_rootdomain(&def_root_domain
);
6653 atomic_set(&def_root_domain
.refcount
, 1);
6656 static struct root_domain
*alloc_rootdomain(void)
6658 struct root_domain
*rd
;
6660 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
6664 if (init_rootdomain(rd
) != 0) {
6672 static void free_sched_domain(struct rcu_head
*rcu
)
6674 struct sched_domain
*sd
= container_of(rcu
, struct sched_domain
, rcu
);
6675 if (atomic_dec_and_test(&sd
->groups
->ref
))
6680 static void destroy_sched_domain(struct sched_domain
*sd
, int cpu
)
6682 call_rcu(&sd
->rcu
, free_sched_domain
);
6685 static void destroy_sched_domains(struct sched_domain
*sd
, int cpu
)
6687 for (; sd
; sd
= sd
->parent
)
6688 destroy_sched_domain(sd
, cpu
);
6692 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
6693 * hold the hotplug lock.
6696 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
6698 struct rq
*rq
= cpu_rq(cpu
);
6699 struct sched_domain
*tmp
;
6701 /* Remove the sched domains which do not contribute to scheduling. */
6702 for (tmp
= sd
; tmp
; ) {
6703 struct sched_domain
*parent
= tmp
->parent
;
6707 if (sd_parent_degenerate(tmp
, parent
)) {
6708 tmp
->parent
= parent
->parent
;
6710 parent
->parent
->child
= tmp
;
6711 destroy_sched_domain(parent
, cpu
);
6716 if (sd
&& sd_degenerate(sd
)) {
6719 destroy_sched_domain(tmp
, cpu
);
6724 /* sched_domain_debug(sd, cpu); */
6726 rq_attach_root(rq
, rd
);
6728 rcu_assign_pointer(rq
->sd
, sd
);
6729 destroy_sched_domains(tmp
, cpu
);
6732 /* cpus with isolated domains */
6733 static cpumask_var_t cpu_isolated_map
;
6735 /* Setup the mask of cpus configured for isolated domains */
6736 static int __init
isolated_cpu_setup(char *str
)
6738 alloc_bootmem_cpumask_var(&cpu_isolated_map
);
6739 cpulist_parse(str
, cpu_isolated_map
);
6743 __setup("isolcpus=", isolated_cpu_setup
);
6745 #define SD_NODES_PER_DOMAIN 16
6750 * find_next_best_node - find the next node to include in a sched_domain
6751 * @node: node whose sched_domain we're building
6752 * @used_nodes: nodes already in the sched_domain
6754 * Find the next node to include in a given scheduling domain. Simply
6755 * finds the closest node not already in the @used_nodes map.
6757 * Should use nodemask_t.
6759 static int find_next_best_node(int node
, nodemask_t
*used_nodes
)
6761 int i
, n
, val
, min_val
, best_node
= 0;
6765 for (i
= 0; i
< nr_node_ids
; i
++) {
6766 /* Start at @node */
6767 n
= (node
+ i
) % nr_node_ids
;
6769 if (!nr_cpus_node(n
))
6772 /* Skip already used nodes */
6773 if (node_isset(n
, *used_nodes
))
6776 /* Simple min distance search */
6777 val
= node_distance(node
, n
);
6779 if (val
< min_val
) {
6785 node_set(best_node
, *used_nodes
);
6790 * sched_domain_node_span - get a cpumask for a node's sched_domain
6791 * @node: node whose cpumask we're constructing
6792 * @span: resulting cpumask
6794 * Given a node, construct a good cpumask for its sched_domain to span. It
6795 * should be one that prevents unnecessary balancing, but also spreads tasks
6798 static void sched_domain_node_span(int node
, struct cpumask
*span
)
6800 nodemask_t used_nodes
;
6803 cpumask_clear(span
);
6804 nodes_clear(used_nodes
);
6806 cpumask_or(span
, span
, cpumask_of_node(node
));
6807 node_set(node
, used_nodes
);
6809 for (i
= 1; i
< SD_NODES_PER_DOMAIN
; i
++) {
6810 int next_node
= find_next_best_node(node
, &used_nodes
);
6812 cpumask_or(span
, span
, cpumask_of_node(next_node
));
6815 #endif /* CONFIG_NUMA */
6817 int sched_smt_power_savings
= 0, sched_mc_power_savings
= 0;
6820 * The cpus mask in sched_group and sched_domain hangs off the end.
6822 * ( See the the comments in include/linux/sched.h:struct sched_group
6823 * and struct sched_domain. )
6825 struct static_sched_group
{
6826 struct sched_group sg
;
6827 DECLARE_BITMAP(cpus
, CONFIG_NR_CPUS
);
6830 struct static_sched_domain
{
6831 struct sched_domain sd
;
6832 DECLARE_BITMAP(span
, CONFIG_NR_CPUS
);
6836 struct sched_domain
**__percpu sd
;
6837 struct sched_group
**__percpu sg
;
6844 cpumask_var_t nodemask
;
6845 cpumask_var_t send_covered
;
6846 struct sched_domain
** __percpu sd
;
6847 struct sd_data sdd
[SD_LV_MAX
];
6848 struct root_domain
*rd
;
6861 * Assumes the sched_domain tree is fully constructed
6863 static int get_group(int cpu
, struct sd_data
*sdd
, struct sched_group
**sg
)
6865 struct sched_domain
*sd
= *per_cpu_ptr(sdd
->sd
, cpu
);
6866 struct sched_domain
*child
= sd
->child
;
6869 cpu
= cpumask_first(sched_domain_span(child
));
6872 *sg
= *per_cpu_ptr(sdd
->sg
, cpu
);
6878 * build_sched_groups takes the cpumask we wish to span, and a pointer
6879 * to a function which identifies what group(along with sched group) a CPU
6880 * belongs to. The return value of group_fn must be a >= 0 and < nr_cpu_ids
6881 * (due to the fact that we keep track of groups covered with a struct cpumask).
6883 * build_sched_groups will build a circular linked list of the groups
6884 * covered by the given span, and will set each group's ->cpumask correctly,
6885 * and ->cpu_power to 0.
6888 build_sched_groups(struct sched_domain
*sd
, struct cpumask
*covered
)
6890 struct sched_group
*first
= NULL
, *last
= NULL
;
6891 struct sd_data
*sdd
= sd
->private;
6892 const struct cpumask
*span
= sched_domain_span(sd
);
6895 cpumask_clear(covered
);
6897 for_each_cpu(i
, span
) {
6898 struct sched_group
*sg
;
6899 int group
= get_group(i
, sdd
, &sg
);
6902 if (cpumask_test_cpu(i
, covered
))
6905 cpumask_clear(sched_group_cpus(sg
));
6908 for_each_cpu(j
, span
) {
6909 if (get_group(j
, sdd
, NULL
) != group
)
6912 cpumask_set_cpu(j
, covered
);
6913 cpumask_set_cpu(j
, sched_group_cpus(sg
));
6926 * Initialize sched groups cpu_power.
6928 * cpu_power indicates the capacity of sched group, which is used while
6929 * distributing the load between different sched groups in a sched domain.
6930 * Typically cpu_power for all the groups in a sched domain will be same unless
6931 * there are asymmetries in the topology. If there are asymmetries, group
6932 * having more cpu_power will pickup more load compared to the group having
6935 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
6937 WARN_ON(!sd
|| !sd
->groups
);
6939 if (cpu
!= group_first_cpu(sd
->groups
))
6942 sd
->groups
->group_weight
= cpumask_weight(sched_group_cpus(sd
->groups
));
6944 update_group_power(sd
, cpu
);
6948 * Initializers for schedule domains
6949 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
6952 #ifdef CONFIG_SCHED_DEBUG
6953 # define SD_INIT_NAME(sd, type) sd->name = #type
6955 # define SD_INIT_NAME(sd, type) do { } while (0)
6958 #define SD_INIT_FUNC(type) \
6959 static noinline struct sched_domain *sd_init_##type(struct s_data *d, int cpu) \
6961 struct sched_domain *sd = *per_cpu_ptr(d->sdd[SD_LV_##type].sd, cpu); \
6962 *sd = SD_##type##_INIT; \
6963 sd->level = SD_LV_##type; \
6964 SD_INIT_NAME(sd, type); \
6965 sd->private = &d->sdd[SD_LV_##type]; \
6971 SD_INIT_FUNC(ALLNODES
)
6974 #ifdef CONFIG_SCHED_SMT
6975 SD_INIT_FUNC(SIBLING
)
6977 #ifdef CONFIG_SCHED_MC
6980 #ifdef CONFIG_SCHED_BOOK
6984 static int default_relax_domain_level
= -1;
6986 static int __init
setup_relax_domain_level(char *str
)
6990 val
= simple_strtoul(str
, NULL
, 0);
6991 if (val
< SD_LV_MAX
)
6992 default_relax_domain_level
= val
;
6996 __setup("relax_domain_level=", setup_relax_domain_level
);
6998 static void set_domain_attribute(struct sched_domain
*sd
,
6999 struct sched_domain_attr
*attr
)
7003 if (!attr
|| attr
->relax_domain_level
< 0) {
7004 if (default_relax_domain_level
< 0)
7007 request
= default_relax_domain_level
;
7009 request
= attr
->relax_domain_level
;
7010 if (request
< sd
->level
) {
7011 /* turn off idle balance on this domain */
7012 sd
->flags
&= ~(SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
7014 /* turn on idle balance on this domain */
7015 sd
->flags
|= (SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
7019 static void __free_domain_allocs(struct s_data
*d
, enum s_alloc what
,
7020 const struct cpumask
*cpu_map
)
7026 if (!atomic_read(&d
->rd
->refcount
))
7027 free_rootdomain(&d
->rd
->rcu
); /* fall through */
7029 free_percpu(d
->sd
); /* fall through */
7031 for (i
= 0; i
< SD_LV_MAX
; i
++) {
7032 for_each_cpu(j
, cpu_map
) {
7033 kfree(*per_cpu_ptr(d
->sdd
[i
].sd
, j
));
7034 kfree(*per_cpu_ptr(d
->sdd
[i
].sg
, j
));
7036 free_percpu(d
->sdd
[i
].sd
);
7037 free_percpu(d
->sdd
[i
].sg
);
7038 } /* fall through */
7039 case sa_send_covered
:
7040 free_cpumask_var(d
->send_covered
); /* fall through */
7042 free_cpumask_var(d
->nodemask
); /* fall through */
7048 static enum s_alloc
__visit_domain_allocation_hell(struct s_data
*d
,
7049 const struct cpumask
*cpu_map
)
7053 memset(d
, 0, sizeof(*d
));
7055 if (!alloc_cpumask_var(&d
->nodemask
, GFP_KERNEL
))
7057 if (!alloc_cpumask_var(&d
->send_covered
, GFP_KERNEL
))
7059 for (i
= 0; i
< SD_LV_MAX
; i
++) {
7060 d
->sdd
[i
].sd
= alloc_percpu(struct sched_domain
*);
7062 return sa_sd_storage
;
7064 d
->sdd
[i
].sg
= alloc_percpu(struct sched_group
*);
7066 return sa_sd_storage
;
7068 for_each_cpu(j
, cpu_map
) {
7069 struct sched_domain
*sd
;
7070 struct sched_group
*sg
;
7072 sd
= kzalloc_node(sizeof(struct sched_domain
) + cpumask_size(),
7073 GFP_KERNEL
, cpu_to_node(j
));
7075 return sa_sd_storage
;
7077 *per_cpu_ptr(d
->sdd
[i
].sd
, j
) = sd
;
7079 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
7080 GFP_KERNEL
, cpu_to_node(j
));
7082 return sa_sd_storage
;
7084 *per_cpu_ptr(d
->sdd
[i
].sg
, j
) = sg
;
7087 d
->sd
= alloc_percpu(struct sched_domain
*);
7089 return sa_sd_storage
;
7090 d
->rd
= alloc_rootdomain();
7093 return sa_rootdomain
;
7097 * NULL the sd_data elements we've used to build the sched_domain and
7098 * sched_group structure so that the subsequent __free_domain_allocs()
7099 * will not free the data we're using.
7101 static void claim_allocations(int cpu
, struct sched_domain
*sd
)
7103 struct sd_data
*sdd
= sd
->private;
7104 struct sched_group
*sg
= sd
->groups
;
7106 WARN_ON_ONCE(*per_cpu_ptr(sdd
->sd
, cpu
) != sd
);
7107 *per_cpu_ptr(sdd
->sd
, cpu
) = NULL
;
7109 if (cpu
== cpumask_first(sched_group_cpus(sg
))) {
7110 WARN_ON_ONCE(*per_cpu_ptr(sdd
->sg
, cpu
) != sg
);
7111 *per_cpu_ptr(sdd
->sg
, cpu
) = NULL
;
7115 static struct sched_domain
*__build_numa_sched_domains(struct s_data
*d
,
7116 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
, int i
)
7118 struct sched_domain
*sd
= NULL
;
7120 struct sched_domain
*parent
;
7123 if (cpumask_weight(cpu_map
) >
7124 SD_NODES_PER_DOMAIN
* cpumask_weight(d
->nodemask
)) {
7125 sd
= sd_init_ALLNODES(d
, i
);
7126 set_domain_attribute(sd
, attr
);
7127 cpumask_copy(sched_domain_span(sd
), cpu_map
);
7132 sd
= sd_init_NODE(d
, i
);
7133 set_domain_attribute(sd
, attr
);
7134 sched_domain_node_span(cpu_to_node(i
), sched_domain_span(sd
));
7135 sd
->parent
= parent
;
7138 cpumask_and(sched_domain_span(sd
), sched_domain_span(sd
), cpu_map
);
7143 static struct sched_domain
*__build_cpu_sched_domain(struct s_data
*d
,
7144 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
7145 struct sched_domain
*parent
, int i
)
7147 struct sched_domain
*sd
;
7148 sd
= sd_init_CPU(d
, i
);
7149 set_domain_attribute(sd
, attr
);
7150 cpumask_copy(sched_domain_span(sd
), d
->nodemask
);
7151 sd
->parent
= parent
;
7157 static struct sched_domain
*__build_book_sched_domain(struct s_data
*d
,
7158 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
7159 struct sched_domain
*parent
, int i
)
7161 struct sched_domain
*sd
= parent
;
7162 #ifdef CONFIG_SCHED_BOOK
7163 sd
= sd_init_BOOK(d
, i
);
7164 set_domain_attribute(sd
, attr
);
7165 cpumask_and(sched_domain_span(sd
), cpu_map
, cpu_book_mask(i
));
7166 sd
->parent
= parent
;
7172 static struct sched_domain
*__build_mc_sched_domain(struct s_data
*d
,
7173 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
7174 struct sched_domain
*parent
, int i
)
7176 struct sched_domain
*sd
= parent
;
7177 #ifdef CONFIG_SCHED_MC
7178 sd
= sd_init_MC(d
, i
);
7179 set_domain_attribute(sd
, attr
);
7180 cpumask_and(sched_domain_span(sd
), cpu_map
, cpu_coregroup_mask(i
));
7181 sd
->parent
= parent
;
7187 static struct sched_domain
*__build_smt_sched_domain(struct s_data
*d
,
7188 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
7189 struct sched_domain
*parent
, int i
)
7191 struct sched_domain
*sd
= parent
;
7192 #ifdef CONFIG_SCHED_SMT
7193 sd
= sd_init_SIBLING(d
, i
);
7194 set_domain_attribute(sd
, attr
);
7195 cpumask_and(sched_domain_span(sd
), cpu_map
, topology_thread_cpumask(i
));
7196 sd
->parent
= parent
;
7203 * Build sched domains for a given set of cpus and attach the sched domains
7204 * to the individual cpus
7206 static int build_sched_domains(const struct cpumask
*cpu_map
,
7207 struct sched_domain_attr
*attr
)
7209 enum s_alloc alloc_state
= sa_none
;
7210 struct sched_domain
*sd
;
7212 int i
, ret
= -ENOMEM
;
7214 alloc_state
= __visit_domain_allocation_hell(&d
, cpu_map
);
7215 if (alloc_state
!= sa_rootdomain
)
7218 /* Set up domains for cpus specified by the cpu_map. */
7219 for_each_cpu(i
, cpu_map
) {
7220 cpumask_and(d
.nodemask
, cpumask_of_node(cpu_to_node(i
)),
7223 sd
= __build_numa_sched_domains(&d
, cpu_map
, attr
, i
);
7224 sd
= __build_cpu_sched_domain(&d
, cpu_map
, attr
, sd
, i
);
7225 sd
= __build_book_sched_domain(&d
, cpu_map
, attr
, sd
, i
);
7226 sd
= __build_mc_sched_domain(&d
, cpu_map
, attr
, sd
, i
);
7227 sd
= __build_smt_sched_domain(&d
, cpu_map
, attr
, sd
, i
);
7229 *per_cpu_ptr(d
.sd
, i
) = sd
;
7232 /* Build the groups for the domains */
7233 for_each_cpu(i
, cpu_map
) {
7234 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
7235 sd
->span_weight
= cpumask_weight(sched_domain_span(sd
));
7236 get_group(i
, sd
->private, &sd
->groups
);
7237 atomic_inc(&sd
->groups
->ref
);
7239 if (i
!= cpumask_first(sched_domain_span(sd
)))
7242 build_sched_groups(sd
, d
.send_covered
);
7246 /* Calculate CPU power for physical packages and nodes */
7247 for (i
= nr_cpumask_bits
-1; i
>= 0; i
--) {
7248 if (!cpumask_test_cpu(i
, cpu_map
))
7251 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
7252 claim_allocations(i
, sd
);
7253 init_sched_groups_power(i
, sd
);
7257 /* Attach the domains */
7259 for_each_cpu(i
, cpu_map
) {
7260 sd
= *per_cpu_ptr(d
.sd
, i
);
7261 cpu_attach_domain(sd
, d
.rd
, i
);
7267 __free_domain_allocs(&d
, alloc_state
, cpu_map
);
7271 static cpumask_var_t
*doms_cur
; /* current sched domains */
7272 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
7273 static struct sched_domain_attr
*dattr_cur
;
7274 /* attribues of custom domains in 'doms_cur' */
7277 * Special case: If a kmalloc of a doms_cur partition (array of
7278 * cpumask) fails, then fallback to a single sched domain,
7279 * as determined by the single cpumask fallback_doms.
7281 static cpumask_var_t fallback_doms
;
7284 * arch_update_cpu_topology lets virtualized architectures update the
7285 * cpu core maps. It is supposed to return 1 if the topology changed
7286 * or 0 if it stayed the same.
7288 int __attribute__((weak
)) arch_update_cpu_topology(void)
7293 cpumask_var_t
*alloc_sched_domains(unsigned int ndoms
)
7296 cpumask_var_t
*doms
;
7298 doms
= kmalloc(sizeof(*doms
) * ndoms
, GFP_KERNEL
);
7301 for (i
= 0; i
< ndoms
; i
++) {
7302 if (!alloc_cpumask_var(&doms
[i
], GFP_KERNEL
)) {
7303 free_sched_domains(doms
, i
);
7310 void free_sched_domains(cpumask_var_t doms
[], unsigned int ndoms
)
7313 for (i
= 0; i
< ndoms
; i
++)
7314 free_cpumask_var(doms
[i
]);
7319 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
7320 * For now this just excludes isolated cpus, but could be used to
7321 * exclude other special cases in the future.
7323 static int init_sched_domains(const struct cpumask
*cpu_map
)
7327 arch_update_cpu_topology();
7329 doms_cur
= alloc_sched_domains(ndoms_cur
);
7331 doms_cur
= &fallback_doms
;
7332 cpumask_andnot(doms_cur
[0], cpu_map
, cpu_isolated_map
);
7334 err
= build_sched_domains(doms_cur
[0], NULL
);
7335 register_sched_domain_sysctl();
7341 * Detach sched domains from a group of cpus specified in cpu_map
7342 * These cpus will now be attached to the NULL domain
7344 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
7349 for_each_cpu(i
, cpu_map
)
7350 cpu_attach_domain(NULL
, &def_root_domain
, i
);
7354 /* handle null as "default" */
7355 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
7356 struct sched_domain_attr
*new, int idx_new
)
7358 struct sched_domain_attr tmp
;
7365 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
7366 new ? (new + idx_new
) : &tmp
,
7367 sizeof(struct sched_domain_attr
));
7371 * Partition sched domains as specified by the 'ndoms_new'
7372 * cpumasks in the array doms_new[] of cpumasks. This compares
7373 * doms_new[] to the current sched domain partitioning, doms_cur[].
7374 * It destroys each deleted domain and builds each new domain.
7376 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
7377 * The masks don't intersect (don't overlap.) We should setup one
7378 * sched domain for each mask. CPUs not in any of the cpumasks will
7379 * not be load balanced. If the same cpumask appears both in the
7380 * current 'doms_cur' domains and in the new 'doms_new', we can leave
7383 * The passed in 'doms_new' should be allocated using
7384 * alloc_sched_domains. This routine takes ownership of it and will
7385 * free_sched_domains it when done with it. If the caller failed the
7386 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
7387 * and partition_sched_domains() will fallback to the single partition
7388 * 'fallback_doms', it also forces the domains to be rebuilt.
7390 * If doms_new == NULL it will be replaced with cpu_online_mask.
7391 * ndoms_new == 0 is a special case for destroying existing domains,
7392 * and it will not create the default domain.
7394 * Call with hotplug lock held
7396 void partition_sched_domains(int ndoms_new
, cpumask_var_t doms_new
[],
7397 struct sched_domain_attr
*dattr_new
)
7402 mutex_lock(&sched_domains_mutex
);
7404 /* always unregister in case we don't destroy any domains */
7405 unregister_sched_domain_sysctl();
7407 /* Let architecture update cpu core mappings. */
7408 new_topology
= arch_update_cpu_topology();
7410 n
= doms_new
? ndoms_new
: 0;
7412 /* Destroy deleted domains */
7413 for (i
= 0; i
< ndoms_cur
; i
++) {
7414 for (j
= 0; j
< n
&& !new_topology
; j
++) {
7415 if (cpumask_equal(doms_cur
[i
], doms_new
[j
])
7416 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
7419 /* no match - a current sched domain not in new doms_new[] */
7420 detach_destroy_domains(doms_cur
[i
]);
7425 if (doms_new
== NULL
) {
7427 doms_new
= &fallback_doms
;
7428 cpumask_andnot(doms_new
[0], cpu_active_mask
, cpu_isolated_map
);
7429 WARN_ON_ONCE(dattr_new
);
7432 /* Build new domains */
7433 for (i
= 0; i
< ndoms_new
; i
++) {
7434 for (j
= 0; j
< ndoms_cur
&& !new_topology
; j
++) {
7435 if (cpumask_equal(doms_new
[i
], doms_cur
[j
])
7436 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
7439 /* no match - add a new doms_new */
7440 build_sched_domains(doms_new
[i
], dattr_new
? dattr_new
+ i
: NULL
);
7445 /* Remember the new sched domains */
7446 if (doms_cur
!= &fallback_doms
)
7447 free_sched_domains(doms_cur
, ndoms_cur
);
7448 kfree(dattr_cur
); /* kfree(NULL) is safe */
7449 doms_cur
= doms_new
;
7450 dattr_cur
= dattr_new
;
7451 ndoms_cur
= ndoms_new
;
7453 register_sched_domain_sysctl();
7455 mutex_unlock(&sched_domains_mutex
);
7458 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
7459 static void reinit_sched_domains(void)
7463 /* Destroy domains first to force the rebuild */
7464 partition_sched_domains(0, NULL
, NULL
);
7466 rebuild_sched_domains();
7470 static ssize_t
sched_power_savings_store(const char *buf
, size_t count
, int smt
)
7472 unsigned int level
= 0;
7474 if (sscanf(buf
, "%u", &level
) != 1)
7478 * level is always be positive so don't check for
7479 * level < POWERSAVINGS_BALANCE_NONE which is 0
7480 * What happens on 0 or 1 byte write,
7481 * need to check for count as well?
7484 if (level
>= MAX_POWERSAVINGS_BALANCE_LEVELS
)
7488 sched_smt_power_savings
= level
;
7490 sched_mc_power_savings
= level
;
7492 reinit_sched_domains();
7497 #ifdef CONFIG_SCHED_MC
7498 static ssize_t
sched_mc_power_savings_show(struct sysdev_class
*class,
7499 struct sysdev_class_attribute
*attr
,
7502 return sprintf(page
, "%u\n", sched_mc_power_savings
);
7504 static ssize_t
sched_mc_power_savings_store(struct sysdev_class
*class,
7505 struct sysdev_class_attribute
*attr
,
7506 const char *buf
, size_t count
)
7508 return sched_power_savings_store(buf
, count
, 0);
7510 static SYSDEV_CLASS_ATTR(sched_mc_power_savings
, 0644,
7511 sched_mc_power_savings_show
,
7512 sched_mc_power_savings_store
);
7515 #ifdef CONFIG_SCHED_SMT
7516 static ssize_t
sched_smt_power_savings_show(struct sysdev_class
*dev
,
7517 struct sysdev_class_attribute
*attr
,
7520 return sprintf(page
, "%u\n", sched_smt_power_savings
);
7522 static ssize_t
sched_smt_power_savings_store(struct sysdev_class
*dev
,
7523 struct sysdev_class_attribute
*attr
,
7524 const char *buf
, size_t count
)
7526 return sched_power_savings_store(buf
, count
, 1);
7528 static SYSDEV_CLASS_ATTR(sched_smt_power_savings
, 0644,
7529 sched_smt_power_savings_show
,
7530 sched_smt_power_savings_store
);
7533 int __init
sched_create_sysfs_power_savings_entries(struct sysdev_class
*cls
)
7537 #ifdef CONFIG_SCHED_SMT
7539 err
= sysfs_create_file(&cls
->kset
.kobj
,
7540 &attr_sched_smt_power_savings
.attr
);
7542 #ifdef CONFIG_SCHED_MC
7543 if (!err
&& mc_capable())
7544 err
= sysfs_create_file(&cls
->kset
.kobj
,
7545 &attr_sched_mc_power_savings
.attr
);
7549 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
7552 * Update cpusets according to cpu_active mask. If cpusets are
7553 * disabled, cpuset_update_active_cpus() becomes a simple wrapper
7554 * around partition_sched_domains().
7556 static int cpuset_cpu_active(struct notifier_block
*nfb
, unsigned long action
,
7559 switch (action
& ~CPU_TASKS_FROZEN
) {
7561 case CPU_DOWN_FAILED
:
7562 cpuset_update_active_cpus();
7569 static int cpuset_cpu_inactive(struct notifier_block
*nfb
, unsigned long action
,
7572 switch (action
& ~CPU_TASKS_FROZEN
) {
7573 case CPU_DOWN_PREPARE
:
7574 cpuset_update_active_cpus();
7581 static int update_runtime(struct notifier_block
*nfb
,
7582 unsigned long action
, void *hcpu
)
7584 int cpu
= (int)(long)hcpu
;
7587 case CPU_DOWN_PREPARE
:
7588 case CPU_DOWN_PREPARE_FROZEN
:
7589 disable_runtime(cpu_rq(cpu
));
7592 case CPU_DOWN_FAILED
:
7593 case CPU_DOWN_FAILED_FROZEN
:
7595 case CPU_ONLINE_FROZEN
:
7596 enable_runtime(cpu_rq(cpu
));
7604 void __init
sched_init_smp(void)
7606 cpumask_var_t non_isolated_cpus
;
7608 alloc_cpumask_var(&non_isolated_cpus
, GFP_KERNEL
);
7609 alloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
7612 mutex_lock(&sched_domains_mutex
);
7613 init_sched_domains(cpu_active_mask
);
7614 cpumask_andnot(non_isolated_cpus
, cpu_possible_mask
, cpu_isolated_map
);
7615 if (cpumask_empty(non_isolated_cpus
))
7616 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus
);
7617 mutex_unlock(&sched_domains_mutex
);
7620 hotcpu_notifier(cpuset_cpu_active
, CPU_PRI_CPUSET_ACTIVE
);
7621 hotcpu_notifier(cpuset_cpu_inactive
, CPU_PRI_CPUSET_INACTIVE
);
7623 /* RT runtime code needs to handle some hotplug events */
7624 hotcpu_notifier(update_runtime
, 0);
7628 /* Move init over to a non-isolated CPU */
7629 if (set_cpus_allowed_ptr(current
, non_isolated_cpus
) < 0)
7631 sched_init_granularity();
7632 free_cpumask_var(non_isolated_cpus
);
7634 init_sched_rt_class();
7637 void __init
sched_init_smp(void)
7639 sched_init_granularity();
7641 #endif /* CONFIG_SMP */
7643 const_debug
unsigned int sysctl_timer_migration
= 1;
7645 int in_sched_functions(unsigned long addr
)
7647 return in_lock_functions(addr
) ||
7648 (addr
>= (unsigned long)__sched_text_start
7649 && addr
< (unsigned long)__sched_text_end
);
7652 static void init_cfs_rq(struct cfs_rq
*cfs_rq
, struct rq
*rq
)
7654 cfs_rq
->tasks_timeline
= RB_ROOT
;
7655 INIT_LIST_HEAD(&cfs_rq
->tasks
);
7656 #ifdef CONFIG_FAIR_GROUP_SCHED
7658 /* allow initial update_cfs_load() to truncate */
7660 cfs_rq
->load_stamp
= 1;
7663 cfs_rq
->min_vruntime
= (u64
)(-(1LL << 20));
7666 static void init_rt_rq(struct rt_rq
*rt_rq
, struct rq
*rq
)
7668 struct rt_prio_array
*array
;
7671 array
= &rt_rq
->active
;
7672 for (i
= 0; i
< MAX_RT_PRIO
; i
++) {
7673 INIT_LIST_HEAD(array
->queue
+ i
);
7674 __clear_bit(i
, array
->bitmap
);
7676 /* delimiter for bitsearch: */
7677 __set_bit(MAX_RT_PRIO
, array
->bitmap
);
7679 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
7680 rt_rq
->highest_prio
.curr
= MAX_RT_PRIO
;
7682 rt_rq
->highest_prio
.next
= MAX_RT_PRIO
;
7686 rt_rq
->rt_nr_migratory
= 0;
7687 rt_rq
->overloaded
= 0;
7688 plist_head_init_raw(&rt_rq
->pushable_tasks
, &rq
->lock
);
7692 rt_rq
->rt_throttled
= 0;
7693 rt_rq
->rt_runtime
= 0;
7694 raw_spin_lock_init(&rt_rq
->rt_runtime_lock
);
7696 #ifdef CONFIG_RT_GROUP_SCHED
7697 rt_rq
->rt_nr_boosted
= 0;
7702 #ifdef CONFIG_FAIR_GROUP_SCHED
7703 static void init_tg_cfs_entry(struct task_group
*tg
, struct cfs_rq
*cfs_rq
,
7704 struct sched_entity
*se
, int cpu
,
7705 struct sched_entity
*parent
)
7707 struct rq
*rq
= cpu_rq(cpu
);
7708 tg
->cfs_rq
[cpu
] = cfs_rq
;
7709 init_cfs_rq(cfs_rq
, rq
);
7713 /* se could be NULL for root_task_group */
7718 se
->cfs_rq
= &rq
->cfs
;
7720 se
->cfs_rq
= parent
->my_q
;
7723 update_load_set(&se
->load
, 0);
7724 se
->parent
= parent
;
7728 #ifdef CONFIG_RT_GROUP_SCHED
7729 static void init_tg_rt_entry(struct task_group
*tg
, struct rt_rq
*rt_rq
,
7730 struct sched_rt_entity
*rt_se
, int cpu
,
7731 struct sched_rt_entity
*parent
)
7733 struct rq
*rq
= cpu_rq(cpu
);
7735 tg
->rt_rq
[cpu
] = rt_rq
;
7736 init_rt_rq(rt_rq
, rq
);
7738 rt_rq
->rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
7740 tg
->rt_se
[cpu
] = rt_se
;
7745 rt_se
->rt_rq
= &rq
->rt
;
7747 rt_se
->rt_rq
= parent
->my_q
;
7749 rt_se
->my_q
= rt_rq
;
7750 rt_se
->parent
= parent
;
7751 INIT_LIST_HEAD(&rt_se
->run_list
);
7755 void __init
sched_init(void)
7758 unsigned long alloc_size
= 0, ptr
;
7760 #ifdef CONFIG_FAIR_GROUP_SCHED
7761 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
7763 #ifdef CONFIG_RT_GROUP_SCHED
7764 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
7766 #ifdef CONFIG_CPUMASK_OFFSTACK
7767 alloc_size
+= num_possible_cpus() * cpumask_size();
7770 ptr
= (unsigned long)kzalloc(alloc_size
, GFP_NOWAIT
);
7772 #ifdef CONFIG_FAIR_GROUP_SCHED
7773 root_task_group
.se
= (struct sched_entity
**)ptr
;
7774 ptr
+= nr_cpu_ids
* sizeof(void **);
7776 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
7777 ptr
+= nr_cpu_ids
* sizeof(void **);
7779 #endif /* CONFIG_FAIR_GROUP_SCHED */
7780 #ifdef CONFIG_RT_GROUP_SCHED
7781 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
7782 ptr
+= nr_cpu_ids
* sizeof(void **);
7784 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
7785 ptr
+= nr_cpu_ids
* sizeof(void **);
7787 #endif /* CONFIG_RT_GROUP_SCHED */
7788 #ifdef CONFIG_CPUMASK_OFFSTACK
7789 for_each_possible_cpu(i
) {
7790 per_cpu(load_balance_tmpmask
, i
) = (void *)ptr
;
7791 ptr
+= cpumask_size();
7793 #endif /* CONFIG_CPUMASK_OFFSTACK */
7797 init_defrootdomain();
7800 init_rt_bandwidth(&def_rt_bandwidth
,
7801 global_rt_period(), global_rt_runtime());
7803 #ifdef CONFIG_RT_GROUP_SCHED
7804 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
7805 global_rt_period(), global_rt_runtime());
7806 #endif /* CONFIG_RT_GROUP_SCHED */
7808 #ifdef CONFIG_CGROUP_SCHED
7809 list_add(&root_task_group
.list
, &task_groups
);
7810 INIT_LIST_HEAD(&root_task_group
.children
);
7811 autogroup_init(&init_task
);
7812 #endif /* CONFIG_CGROUP_SCHED */
7814 for_each_possible_cpu(i
) {
7818 raw_spin_lock_init(&rq
->lock
);
7820 rq
->calc_load_active
= 0;
7821 rq
->calc_load_update
= jiffies
+ LOAD_FREQ
;
7822 init_cfs_rq(&rq
->cfs
, rq
);
7823 init_rt_rq(&rq
->rt
, rq
);
7824 #ifdef CONFIG_FAIR_GROUP_SCHED
7825 root_task_group
.shares
= root_task_group_load
;
7826 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
7828 * How much cpu bandwidth does root_task_group get?
7830 * In case of task-groups formed thr' the cgroup filesystem, it
7831 * gets 100% of the cpu resources in the system. This overall
7832 * system cpu resource is divided among the tasks of
7833 * root_task_group and its child task-groups in a fair manner,
7834 * based on each entity's (task or task-group's) weight
7835 * (se->load.weight).
7837 * In other words, if root_task_group has 10 tasks of weight
7838 * 1024) and two child groups A0 and A1 (of weight 1024 each),
7839 * then A0's share of the cpu resource is:
7841 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
7843 * We achieve this by letting root_task_group's tasks sit
7844 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
7846 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, NULL
);
7847 #endif /* CONFIG_FAIR_GROUP_SCHED */
7849 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
7850 #ifdef CONFIG_RT_GROUP_SCHED
7851 INIT_LIST_HEAD(&rq
->leaf_rt_rq_list
);
7852 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, NULL
);
7855 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
7856 rq
->cpu_load
[j
] = 0;
7858 rq
->last_load_update_tick
= jiffies
;
7863 rq
->cpu_power
= SCHED_LOAD_SCALE
;
7864 rq
->post_schedule
= 0;
7865 rq
->active_balance
= 0;
7866 rq
->next_balance
= jiffies
;
7871 rq
->avg_idle
= 2*sysctl_sched_migration_cost
;
7872 rq_attach_root(rq
, &def_root_domain
);
7874 rq
->nohz_balance_kick
= 0;
7875 init_sched_softirq_csd(&per_cpu(remote_sched_softirq_cb
, i
));
7879 atomic_set(&rq
->nr_iowait
, 0);
7882 set_load_weight(&init_task
);
7884 #ifdef CONFIG_PREEMPT_NOTIFIERS
7885 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
7889 open_softirq(SCHED_SOFTIRQ
, run_rebalance_domains
);
7892 #ifdef CONFIG_RT_MUTEXES
7893 plist_head_init_raw(&init_task
.pi_waiters
, &init_task
.pi_lock
);
7897 * The boot idle thread does lazy MMU switching as well:
7899 atomic_inc(&init_mm
.mm_count
);
7900 enter_lazy_tlb(&init_mm
, current
);
7903 * Make us the idle thread. Technically, schedule() should not be
7904 * called from this thread, however somewhere below it might be,
7905 * but because we are the idle thread, we just pick up running again
7906 * when this runqueue becomes "idle".
7908 init_idle(current
, smp_processor_id());
7910 calc_load_update
= jiffies
+ LOAD_FREQ
;
7913 * During early bootup we pretend to be a normal task:
7915 current
->sched_class
= &fair_sched_class
;
7917 /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */
7918 zalloc_cpumask_var(&nohz_cpu_mask
, GFP_NOWAIT
);
7921 zalloc_cpumask_var(&nohz
.idle_cpus_mask
, GFP_NOWAIT
);
7922 alloc_cpumask_var(&nohz
.grp_idle_mask
, GFP_NOWAIT
);
7923 atomic_set(&nohz
.load_balancer
, nr_cpu_ids
);
7924 atomic_set(&nohz
.first_pick_cpu
, nr_cpu_ids
);
7925 atomic_set(&nohz
.second_pick_cpu
, nr_cpu_ids
);
7927 /* May be allocated at isolcpus cmdline parse time */
7928 if (cpu_isolated_map
== NULL
)
7929 zalloc_cpumask_var(&cpu_isolated_map
, GFP_NOWAIT
);
7932 scheduler_running
= 1;
7935 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
7936 static inline int preempt_count_equals(int preempt_offset
)
7938 int nested
= (preempt_count() & ~PREEMPT_ACTIVE
) + rcu_preempt_depth();
7940 return (nested
== preempt_offset
);
7943 void __might_sleep(const char *file
, int line
, int preempt_offset
)
7946 static unsigned long prev_jiffy
; /* ratelimiting */
7948 if ((preempt_count_equals(preempt_offset
) && !irqs_disabled()) ||
7949 system_state
!= SYSTEM_RUNNING
|| oops_in_progress
)
7951 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
7953 prev_jiffy
= jiffies
;
7956 "BUG: sleeping function called from invalid context at %s:%d\n",
7959 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
7960 in_atomic(), irqs_disabled(),
7961 current
->pid
, current
->comm
);
7963 debug_show_held_locks(current
);
7964 if (irqs_disabled())
7965 print_irqtrace_events(current
);
7969 EXPORT_SYMBOL(__might_sleep
);
7972 #ifdef CONFIG_MAGIC_SYSRQ
7973 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
7975 const struct sched_class
*prev_class
= p
->sched_class
;
7976 int old_prio
= p
->prio
;
7979 on_rq
= p
->se
.on_rq
;
7981 deactivate_task(rq
, p
, 0);
7982 __setscheduler(rq
, p
, SCHED_NORMAL
, 0);
7984 activate_task(rq
, p
, 0);
7985 resched_task(rq
->curr
);
7988 check_class_changed(rq
, p
, prev_class
, old_prio
);
7991 void normalize_rt_tasks(void)
7993 struct task_struct
*g
, *p
;
7994 unsigned long flags
;
7997 read_lock_irqsave(&tasklist_lock
, flags
);
7998 do_each_thread(g
, p
) {
8000 * Only normalize user tasks:
8005 p
->se
.exec_start
= 0;
8006 #ifdef CONFIG_SCHEDSTATS
8007 p
->se
.statistics
.wait_start
= 0;
8008 p
->se
.statistics
.sleep_start
= 0;
8009 p
->se
.statistics
.block_start
= 0;
8014 * Renice negative nice level userspace
8017 if (TASK_NICE(p
) < 0 && p
->mm
)
8018 set_user_nice(p
, 0);
8022 raw_spin_lock(&p
->pi_lock
);
8023 rq
= __task_rq_lock(p
);
8025 normalize_task(rq
, p
);
8027 __task_rq_unlock(rq
);
8028 raw_spin_unlock(&p
->pi_lock
);
8029 } while_each_thread(g
, p
);
8031 read_unlock_irqrestore(&tasklist_lock
, flags
);
8034 #endif /* CONFIG_MAGIC_SYSRQ */
8036 #if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
8038 * These functions are only useful for the IA64 MCA handling, or kdb.
8040 * They can only be called when the whole system has been
8041 * stopped - every CPU needs to be quiescent, and no scheduling
8042 * activity can take place. Using them for anything else would
8043 * be a serious bug, and as a result, they aren't even visible
8044 * under any other configuration.
8048 * curr_task - return the current task for a given cpu.
8049 * @cpu: the processor in question.
8051 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
8053 struct task_struct
*curr_task(int cpu
)
8055 return cpu_curr(cpu
);
8058 #endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
8062 * set_curr_task - set the current task for a given cpu.
8063 * @cpu: the processor in question.
8064 * @p: the task pointer to set.
8066 * Description: This function must only be used when non-maskable interrupts
8067 * are serviced on a separate stack. It allows the architecture to switch the
8068 * notion of the current task on a cpu in a non-blocking manner. This function
8069 * must be called with all CPU's synchronized, and interrupts disabled, the
8070 * and caller must save the original value of the current task (see
8071 * curr_task() above) and restore that value before reenabling interrupts and
8072 * re-starting the system.
8074 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
8076 void set_curr_task(int cpu
, struct task_struct
*p
)
8083 #ifdef CONFIG_FAIR_GROUP_SCHED
8084 static void free_fair_sched_group(struct task_group
*tg
)
8088 for_each_possible_cpu(i
) {
8090 kfree(tg
->cfs_rq
[i
]);
8100 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8102 struct cfs_rq
*cfs_rq
;
8103 struct sched_entity
*se
;
8106 tg
->cfs_rq
= kzalloc(sizeof(cfs_rq
) * nr_cpu_ids
, GFP_KERNEL
);
8109 tg
->se
= kzalloc(sizeof(se
) * nr_cpu_ids
, GFP_KERNEL
);
8113 tg
->shares
= NICE_0_LOAD
;
8115 for_each_possible_cpu(i
) {
8116 cfs_rq
= kzalloc_node(sizeof(struct cfs_rq
),
8117 GFP_KERNEL
, cpu_to_node(i
));
8121 se
= kzalloc_node(sizeof(struct sched_entity
),
8122 GFP_KERNEL
, cpu_to_node(i
));
8126 init_tg_cfs_entry(tg
, cfs_rq
, se
, i
, parent
->se
[i
]);
8137 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
8139 struct rq
*rq
= cpu_rq(cpu
);
8140 unsigned long flags
;
8143 * Only empty task groups can be destroyed; so we can speculatively
8144 * check on_list without danger of it being re-added.
8146 if (!tg
->cfs_rq
[cpu
]->on_list
)
8149 raw_spin_lock_irqsave(&rq
->lock
, flags
);
8150 list_del_leaf_cfs_rq(tg
->cfs_rq
[cpu
]);
8151 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
8153 #else /* !CONFG_FAIR_GROUP_SCHED */
8154 static inline void free_fair_sched_group(struct task_group
*tg
)
8159 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8164 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
8167 #endif /* CONFIG_FAIR_GROUP_SCHED */
8169 #ifdef CONFIG_RT_GROUP_SCHED
8170 static void free_rt_sched_group(struct task_group
*tg
)
8174 destroy_rt_bandwidth(&tg
->rt_bandwidth
);
8176 for_each_possible_cpu(i
) {
8178 kfree(tg
->rt_rq
[i
]);
8180 kfree(tg
->rt_se
[i
]);
8188 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8190 struct rt_rq
*rt_rq
;
8191 struct sched_rt_entity
*rt_se
;
8195 tg
->rt_rq
= kzalloc(sizeof(rt_rq
) * nr_cpu_ids
, GFP_KERNEL
);
8198 tg
->rt_se
= kzalloc(sizeof(rt_se
) * nr_cpu_ids
, GFP_KERNEL
);
8202 init_rt_bandwidth(&tg
->rt_bandwidth
,
8203 ktime_to_ns(def_rt_bandwidth
.rt_period
), 0);
8205 for_each_possible_cpu(i
) {
8208 rt_rq
= kzalloc_node(sizeof(struct rt_rq
),
8209 GFP_KERNEL
, cpu_to_node(i
));
8213 rt_se
= kzalloc_node(sizeof(struct sched_rt_entity
),
8214 GFP_KERNEL
, cpu_to_node(i
));
8218 init_tg_rt_entry(tg
, rt_rq
, rt_se
, i
, parent
->rt_se
[i
]);
8228 #else /* !CONFIG_RT_GROUP_SCHED */
8229 static inline void free_rt_sched_group(struct task_group
*tg
)
8234 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8238 #endif /* CONFIG_RT_GROUP_SCHED */
8240 #ifdef CONFIG_CGROUP_SCHED
8241 static void free_sched_group(struct task_group
*tg
)
8243 free_fair_sched_group(tg
);
8244 free_rt_sched_group(tg
);
8249 /* allocate runqueue etc for a new task group */
8250 struct task_group
*sched_create_group(struct task_group
*parent
)
8252 struct task_group
*tg
;
8253 unsigned long flags
;
8255 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
8257 return ERR_PTR(-ENOMEM
);
8259 if (!alloc_fair_sched_group(tg
, parent
))
8262 if (!alloc_rt_sched_group(tg
, parent
))
8265 spin_lock_irqsave(&task_group_lock
, flags
);
8266 list_add_rcu(&tg
->list
, &task_groups
);
8268 WARN_ON(!parent
); /* root should already exist */
8270 tg
->parent
= parent
;
8271 INIT_LIST_HEAD(&tg
->children
);
8272 list_add_rcu(&tg
->siblings
, &parent
->children
);
8273 spin_unlock_irqrestore(&task_group_lock
, flags
);
8278 free_sched_group(tg
);
8279 return ERR_PTR(-ENOMEM
);
8282 /* rcu callback to free various structures associated with a task group */
8283 static void free_sched_group_rcu(struct rcu_head
*rhp
)
8285 /* now it should be safe to free those cfs_rqs */
8286 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
8289 /* Destroy runqueue etc associated with a task group */
8290 void sched_destroy_group(struct task_group
*tg
)
8292 unsigned long flags
;
8295 /* end participation in shares distribution */
8296 for_each_possible_cpu(i
)
8297 unregister_fair_sched_group(tg
, i
);
8299 spin_lock_irqsave(&task_group_lock
, flags
);
8300 list_del_rcu(&tg
->list
);
8301 list_del_rcu(&tg
->siblings
);
8302 spin_unlock_irqrestore(&task_group_lock
, flags
);
8304 /* wait for possible concurrent references to cfs_rqs complete */
8305 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
8308 /* change task's runqueue when it moves between groups.
8309 * The caller of this function should have put the task in its new group
8310 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
8311 * reflect its new group.
8313 void sched_move_task(struct task_struct
*tsk
)
8316 unsigned long flags
;
8319 rq
= task_rq_lock(tsk
, &flags
);
8321 running
= task_current(rq
, tsk
);
8322 on_rq
= tsk
->se
.on_rq
;
8325 dequeue_task(rq
, tsk
, 0);
8326 if (unlikely(running
))
8327 tsk
->sched_class
->put_prev_task(rq
, tsk
);
8329 #ifdef CONFIG_FAIR_GROUP_SCHED
8330 if (tsk
->sched_class
->task_move_group
)
8331 tsk
->sched_class
->task_move_group(tsk
, on_rq
);
8334 set_task_rq(tsk
, task_cpu(tsk
));
8336 if (unlikely(running
))
8337 tsk
->sched_class
->set_curr_task(rq
);
8339 enqueue_task(rq
, tsk
, 0);
8341 task_rq_unlock(rq
, &flags
);
8343 #endif /* CONFIG_CGROUP_SCHED */
8345 #ifdef CONFIG_FAIR_GROUP_SCHED
8346 static DEFINE_MUTEX(shares_mutex
);
8348 int sched_group_set_shares(struct task_group
*tg
, unsigned long shares
)
8351 unsigned long flags
;
8354 * We can't change the weight of the root cgroup.
8359 if (shares
< MIN_SHARES
)
8360 shares
= MIN_SHARES
;
8361 else if (shares
> MAX_SHARES
)
8362 shares
= MAX_SHARES
;
8364 mutex_lock(&shares_mutex
);
8365 if (tg
->shares
== shares
)
8368 tg
->shares
= shares
;
8369 for_each_possible_cpu(i
) {
8370 struct rq
*rq
= cpu_rq(i
);
8371 struct sched_entity
*se
;
8374 /* Propagate contribution to hierarchy */
8375 raw_spin_lock_irqsave(&rq
->lock
, flags
);
8376 for_each_sched_entity(se
)
8377 update_cfs_shares(group_cfs_rq(se
));
8378 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
8382 mutex_unlock(&shares_mutex
);
8386 unsigned long sched_group_shares(struct task_group
*tg
)
8392 #ifdef CONFIG_RT_GROUP_SCHED
8394 * Ensure that the real time constraints are schedulable.
8396 static DEFINE_MUTEX(rt_constraints_mutex
);
8398 static unsigned long to_ratio(u64 period
, u64 runtime
)
8400 if (runtime
== RUNTIME_INF
)
8403 return div64_u64(runtime
<< 20, period
);
8406 /* Must be called with tasklist_lock held */
8407 static inline int tg_has_rt_tasks(struct task_group
*tg
)
8409 struct task_struct
*g
, *p
;
8411 do_each_thread(g
, p
) {
8412 if (rt_task(p
) && rt_rq_of_se(&p
->rt
)->tg
== tg
)
8414 } while_each_thread(g
, p
);
8419 struct rt_schedulable_data
{
8420 struct task_group
*tg
;
8425 static int tg_schedulable(struct task_group
*tg
, void *data
)
8427 struct rt_schedulable_data
*d
= data
;
8428 struct task_group
*child
;
8429 unsigned long total
, sum
= 0;
8430 u64 period
, runtime
;
8432 period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8433 runtime
= tg
->rt_bandwidth
.rt_runtime
;
8436 period
= d
->rt_period
;
8437 runtime
= d
->rt_runtime
;
8441 * Cannot have more runtime than the period.
8443 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
8447 * Ensure we don't starve existing RT tasks.
8449 if (rt_bandwidth_enabled() && !runtime
&& tg_has_rt_tasks(tg
))
8452 total
= to_ratio(period
, runtime
);
8455 * Nobody can have more than the global setting allows.
8457 if (total
> to_ratio(global_rt_period(), global_rt_runtime()))
8461 * The sum of our children's runtime should not exceed our own.
8463 list_for_each_entry_rcu(child
, &tg
->children
, siblings
) {
8464 period
= ktime_to_ns(child
->rt_bandwidth
.rt_period
);
8465 runtime
= child
->rt_bandwidth
.rt_runtime
;
8467 if (child
== d
->tg
) {
8468 period
= d
->rt_period
;
8469 runtime
= d
->rt_runtime
;
8472 sum
+= to_ratio(period
, runtime
);
8481 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
8483 struct rt_schedulable_data data
= {
8485 .rt_period
= period
,
8486 .rt_runtime
= runtime
,
8489 return walk_tg_tree(tg_schedulable
, tg_nop
, &data
);
8492 static int tg_set_bandwidth(struct task_group
*tg
,
8493 u64 rt_period
, u64 rt_runtime
)
8497 mutex_lock(&rt_constraints_mutex
);
8498 read_lock(&tasklist_lock
);
8499 err
= __rt_schedulable(tg
, rt_period
, rt_runtime
);
8503 raw_spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
8504 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
8505 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
8507 for_each_possible_cpu(i
) {
8508 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
8510 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
8511 rt_rq
->rt_runtime
= rt_runtime
;
8512 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
8514 raw_spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
8516 read_unlock(&tasklist_lock
);
8517 mutex_unlock(&rt_constraints_mutex
);
8522 int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
8524 u64 rt_runtime
, rt_period
;
8526 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8527 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
8528 if (rt_runtime_us
< 0)
8529 rt_runtime
= RUNTIME_INF
;
8531 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
8534 long sched_group_rt_runtime(struct task_group
*tg
)
8538 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
8541 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
8542 do_div(rt_runtime_us
, NSEC_PER_USEC
);
8543 return rt_runtime_us
;
8546 int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
8548 u64 rt_runtime
, rt_period
;
8550 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
8551 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
8556 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
8559 long sched_group_rt_period(struct task_group
*tg
)
8563 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8564 do_div(rt_period_us
, NSEC_PER_USEC
);
8565 return rt_period_us
;
8568 static int sched_rt_global_constraints(void)
8570 u64 runtime
, period
;
8573 if (sysctl_sched_rt_period
<= 0)
8576 runtime
= global_rt_runtime();
8577 period
= global_rt_period();
8580 * Sanity check on the sysctl variables.
8582 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
8585 mutex_lock(&rt_constraints_mutex
);
8586 read_lock(&tasklist_lock
);
8587 ret
= __rt_schedulable(NULL
, 0, 0);
8588 read_unlock(&tasklist_lock
);
8589 mutex_unlock(&rt_constraints_mutex
);
8594 int sched_rt_can_attach(struct task_group
*tg
, struct task_struct
*tsk
)
8596 /* Don't accept realtime tasks when there is no way for them to run */
8597 if (rt_task(tsk
) && tg
->rt_bandwidth
.rt_runtime
== 0)
8603 #else /* !CONFIG_RT_GROUP_SCHED */
8604 static int sched_rt_global_constraints(void)
8606 unsigned long flags
;
8609 if (sysctl_sched_rt_period
<= 0)
8613 * There's always some RT tasks in the root group
8614 * -- migration, kstopmachine etc..
8616 if (sysctl_sched_rt_runtime
== 0)
8619 raw_spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
8620 for_each_possible_cpu(i
) {
8621 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
8623 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
8624 rt_rq
->rt_runtime
= global_rt_runtime();
8625 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
8627 raw_spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
8631 #endif /* CONFIG_RT_GROUP_SCHED */
8633 int sched_rt_handler(struct ctl_table
*table
, int write
,
8634 void __user
*buffer
, size_t *lenp
,
8638 int old_period
, old_runtime
;
8639 static DEFINE_MUTEX(mutex
);
8642 old_period
= sysctl_sched_rt_period
;
8643 old_runtime
= sysctl_sched_rt_runtime
;
8645 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
8647 if (!ret
&& write
) {
8648 ret
= sched_rt_global_constraints();
8650 sysctl_sched_rt_period
= old_period
;
8651 sysctl_sched_rt_runtime
= old_runtime
;
8653 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
8654 def_rt_bandwidth
.rt_period
=
8655 ns_to_ktime(global_rt_period());
8658 mutex_unlock(&mutex
);
8663 #ifdef CONFIG_CGROUP_SCHED
8665 /* return corresponding task_group object of a cgroup */
8666 static inline struct task_group
*cgroup_tg(struct cgroup
*cgrp
)
8668 return container_of(cgroup_subsys_state(cgrp
, cpu_cgroup_subsys_id
),
8669 struct task_group
, css
);
8672 static struct cgroup_subsys_state
*
8673 cpu_cgroup_create(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8675 struct task_group
*tg
, *parent
;
8677 if (!cgrp
->parent
) {
8678 /* This is early initialization for the top cgroup */
8679 return &root_task_group
.css
;
8682 parent
= cgroup_tg(cgrp
->parent
);
8683 tg
= sched_create_group(parent
);
8685 return ERR_PTR(-ENOMEM
);
8691 cpu_cgroup_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8693 struct task_group
*tg
= cgroup_tg(cgrp
);
8695 sched_destroy_group(tg
);
8699 cpu_cgroup_can_attach_task(struct cgroup
*cgrp
, struct task_struct
*tsk
)
8701 #ifdef CONFIG_RT_GROUP_SCHED
8702 if (!sched_rt_can_attach(cgroup_tg(cgrp
), tsk
))
8705 /* We don't support RT-tasks being in separate groups */
8706 if (tsk
->sched_class
!= &fair_sched_class
)
8713 cpu_cgroup_can_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
8714 struct task_struct
*tsk
, bool threadgroup
)
8716 int retval
= cpu_cgroup_can_attach_task(cgrp
, tsk
);
8720 struct task_struct
*c
;
8722 list_for_each_entry_rcu(c
, &tsk
->thread_group
, thread_group
) {
8723 retval
= cpu_cgroup_can_attach_task(cgrp
, c
);
8735 cpu_cgroup_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
8736 struct cgroup
*old_cont
, struct task_struct
*tsk
,
8739 sched_move_task(tsk
);
8741 struct task_struct
*c
;
8743 list_for_each_entry_rcu(c
, &tsk
->thread_group
, thread_group
) {
8751 cpu_cgroup_exit(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
8752 struct cgroup
*old_cgrp
, struct task_struct
*task
)
8755 * cgroup_exit() is called in the copy_process() failure path.
8756 * Ignore this case since the task hasn't ran yet, this avoids
8757 * trying to poke a half freed task state from generic code.
8759 if (!(task
->flags
& PF_EXITING
))
8762 sched_move_task(task
);
8765 #ifdef CONFIG_FAIR_GROUP_SCHED
8766 static int cpu_shares_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
8769 return sched_group_set_shares(cgroup_tg(cgrp
), shareval
);
8772 static u64
cpu_shares_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
8774 struct task_group
*tg
= cgroup_tg(cgrp
);
8776 return (u64
) tg
->shares
;
8778 #endif /* CONFIG_FAIR_GROUP_SCHED */
8780 #ifdef CONFIG_RT_GROUP_SCHED
8781 static int cpu_rt_runtime_write(struct cgroup
*cgrp
, struct cftype
*cft
,
8784 return sched_group_set_rt_runtime(cgroup_tg(cgrp
), val
);
8787 static s64
cpu_rt_runtime_read(struct cgroup
*cgrp
, struct cftype
*cft
)
8789 return sched_group_rt_runtime(cgroup_tg(cgrp
));
8792 static int cpu_rt_period_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
8795 return sched_group_set_rt_period(cgroup_tg(cgrp
), rt_period_us
);
8798 static u64
cpu_rt_period_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
8800 return sched_group_rt_period(cgroup_tg(cgrp
));
8802 #endif /* CONFIG_RT_GROUP_SCHED */
8804 static struct cftype cpu_files
[] = {
8805 #ifdef CONFIG_FAIR_GROUP_SCHED
8808 .read_u64
= cpu_shares_read_u64
,
8809 .write_u64
= cpu_shares_write_u64
,
8812 #ifdef CONFIG_RT_GROUP_SCHED
8814 .name
= "rt_runtime_us",
8815 .read_s64
= cpu_rt_runtime_read
,
8816 .write_s64
= cpu_rt_runtime_write
,
8819 .name
= "rt_period_us",
8820 .read_u64
= cpu_rt_period_read_uint
,
8821 .write_u64
= cpu_rt_period_write_uint
,
8826 static int cpu_cgroup_populate(struct cgroup_subsys
*ss
, struct cgroup
*cont
)
8828 return cgroup_add_files(cont
, ss
, cpu_files
, ARRAY_SIZE(cpu_files
));
8831 struct cgroup_subsys cpu_cgroup_subsys
= {
8833 .create
= cpu_cgroup_create
,
8834 .destroy
= cpu_cgroup_destroy
,
8835 .can_attach
= cpu_cgroup_can_attach
,
8836 .attach
= cpu_cgroup_attach
,
8837 .exit
= cpu_cgroup_exit
,
8838 .populate
= cpu_cgroup_populate
,
8839 .subsys_id
= cpu_cgroup_subsys_id
,
8843 #endif /* CONFIG_CGROUP_SCHED */
8845 #ifdef CONFIG_CGROUP_CPUACCT
8848 * CPU accounting code for task groups.
8850 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
8851 * (balbir@in.ibm.com).
8854 /* track cpu usage of a group of tasks and its child groups */
8856 struct cgroup_subsys_state css
;
8857 /* cpuusage holds pointer to a u64-type object on every cpu */
8858 u64 __percpu
*cpuusage
;
8859 struct percpu_counter cpustat
[CPUACCT_STAT_NSTATS
];
8860 struct cpuacct
*parent
;
8863 struct cgroup_subsys cpuacct_subsys
;
8865 /* return cpu accounting group corresponding to this container */
8866 static inline struct cpuacct
*cgroup_ca(struct cgroup
*cgrp
)
8868 return container_of(cgroup_subsys_state(cgrp
, cpuacct_subsys_id
),
8869 struct cpuacct
, css
);
8872 /* return cpu accounting group to which this task belongs */
8873 static inline struct cpuacct
*task_ca(struct task_struct
*tsk
)
8875 return container_of(task_subsys_state(tsk
, cpuacct_subsys_id
),
8876 struct cpuacct
, css
);
8879 /* create a new cpu accounting group */
8880 static struct cgroup_subsys_state
*cpuacct_create(
8881 struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8883 struct cpuacct
*ca
= kzalloc(sizeof(*ca
), GFP_KERNEL
);
8889 ca
->cpuusage
= alloc_percpu(u64
);
8893 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++)
8894 if (percpu_counter_init(&ca
->cpustat
[i
], 0))
8895 goto out_free_counters
;
8898 ca
->parent
= cgroup_ca(cgrp
->parent
);
8904 percpu_counter_destroy(&ca
->cpustat
[i
]);
8905 free_percpu(ca
->cpuusage
);
8909 return ERR_PTR(-ENOMEM
);
8912 /* destroy an existing cpu accounting group */
8914 cpuacct_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8916 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8919 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++)
8920 percpu_counter_destroy(&ca
->cpustat
[i
]);
8921 free_percpu(ca
->cpuusage
);
8925 static u64
cpuacct_cpuusage_read(struct cpuacct
*ca
, int cpu
)
8927 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
8930 #ifndef CONFIG_64BIT
8932 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
8934 raw_spin_lock_irq(&cpu_rq(cpu
)->lock
);
8936 raw_spin_unlock_irq(&cpu_rq(cpu
)->lock
);
8944 static void cpuacct_cpuusage_write(struct cpuacct
*ca
, int cpu
, u64 val
)
8946 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
8948 #ifndef CONFIG_64BIT
8950 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
8952 raw_spin_lock_irq(&cpu_rq(cpu
)->lock
);
8954 raw_spin_unlock_irq(&cpu_rq(cpu
)->lock
);
8960 /* return total cpu usage (in nanoseconds) of a group */
8961 static u64
cpuusage_read(struct cgroup
*cgrp
, struct cftype
*cft
)
8963 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8964 u64 totalcpuusage
= 0;
8967 for_each_present_cpu(i
)
8968 totalcpuusage
+= cpuacct_cpuusage_read(ca
, i
);
8970 return totalcpuusage
;
8973 static int cpuusage_write(struct cgroup
*cgrp
, struct cftype
*cftype
,
8976 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8985 for_each_present_cpu(i
)
8986 cpuacct_cpuusage_write(ca
, i
, 0);
8992 static int cpuacct_percpu_seq_read(struct cgroup
*cgroup
, struct cftype
*cft
,
8995 struct cpuacct
*ca
= cgroup_ca(cgroup
);
8999 for_each_present_cpu(i
) {
9000 percpu
= cpuacct_cpuusage_read(ca
, i
);
9001 seq_printf(m
, "%llu ", (unsigned long long) percpu
);
9003 seq_printf(m
, "\n");
9007 static const char *cpuacct_stat_desc
[] = {
9008 [CPUACCT_STAT_USER
] = "user",
9009 [CPUACCT_STAT_SYSTEM
] = "system",
9012 static int cpuacct_stats_show(struct cgroup
*cgrp
, struct cftype
*cft
,
9013 struct cgroup_map_cb
*cb
)
9015 struct cpuacct
*ca
= cgroup_ca(cgrp
);
9018 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++) {
9019 s64 val
= percpu_counter_read(&ca
->cpustat
[i
]);
9020 val
= cputime64_to_clock_t(val
);
9021 cb
->fill(cb
, cpuacct_stat_desc
[i
], val
);
9026 static struct cftype files
[] = {
9029 .read_u64
= cpuusage_read
,
9030 .write_u64
= cpuusage_write
,
9033 .name
= "usage_percpu",
9034 .read_seq_string
= cpuacct_percpu_seq_read
,
9038 .read_map
= cpuacct_stats_show
,
9042 static int cpuacct_populate(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9044 return cgroup_add_files(cgrp
, ss
, files
, ARRAY_SIZE(files
));
9048 * charge this task's execution time to its accounting group.
9050 * called with rq->lock held.
9052 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
)
9057 if (unlikely(!cpuacct_subsys
.active
))
9060 cpu
= task_cpu(tsk
);
9066 for (; ca
; ca
= ca
->parent
) {
9067 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
9068 *cpuusage
+= cputime
;
9075 * When CONFIG_VIRT_CPU_ACCOUNTING is enabled one jiffy can be very large
9076 * in cputime_t units. As a result, cpuacct_update_stats calls
9077 * percpu_counter_add with values large enough to always overflow the
9078 * per cpu batch limit causing bad SMP scalability.
9080 * To fix this we scale percpu_counter_batch by cputime_one_jiffy so we
9081 * batch the same amount of time with CONFIG_VIRT_CPU_ACCOUNTING disabled
9082 * and enabled. We cap it at INT_MAX which is the largest allowed batch value.
9085 #define CPUACCT_BATCH \
9086 min_t(long, percpu_counter_batch * cputime_one_jiffy, INT_MAX)
9088 #define CPUACCT_BATCH 0
9092 * Charge the system/user time to the task's accounting group.
9094 static void cpuacct_update_stats(struct task_struct
*tsk
,
9095 enum cpuacct_stat_index idx
, cputime_t val
)
9098 int batch
= CPUACCT_BATCH
;
9100 if (unlikely(!cpuacct_subsys
.active
))
9107 __percpu_counter_add(&ca
->cpustat
[idx
], val
, batch
);
9113 struct cgroup_subsys cpuacct_subsys
= {
9115 .create
= cpuacct_create
,
9116 .destroy
= cpuacct_destroy
,
9117 .populate
= cpuacct_populate
,
9118 .subsys_id
= cpuacct_subsys_id
,
9120 #endif /* CONFIG_CGROUP_CPUACCT */