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 arch_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
421 cpumask_var_t online
;
424 * The "RT overload" flag: it gets set if a CPU has more than
425 * one runnable RT task.
427 cpumask_var_t rto_mask
;
429 struct cpupri cpupri
;
433 * By default the system creates a single root-domain with all cpus as
434 * members (mimicking the global state we have today).
436 static struct root_domain def_root_domain
;
438 #endif /* CONFIG_SMP */
441 * This is the main, per-CPU runqueue data structure.
443 * Locking rule: those places that want to lock multiple runqueues
444 * (such as the load balancing or the thread migration code), lock
445 * acquire operations must be ordered by ascending &runqueue.
452 * nr_running and cpu_load should be in the same cacheline because
453 * remote CPUs use both these fields when doing load calculation.
455 unsigned long nr_running
;
456 #define CPU_LOAD_IDX_MAX 5
457 unsigned long cpu_load
[CPU_LOAD_IDX_MAX
];
458 unsigned long last_load_update_tick
;
461 unsigned char nohz_balance_kick
;
463 unsigned int skip_clock_update
;
465 /* capture load from *all* tasks on this cpu: */
466 struct load_weight load
;
467 unsigned long nr_load_updates
;
473 #ifdef CONFIG_FAIR_GROUP_SCHED
474 /* list of leaf cfs_rq on this cpu: */
475 struct list_head leaf_cfs_rq_list
;
477 #ifdef CONFIG_RT_GROUP_SCHED
478 struct list_head leaf_rt_rq_list
;
482 * This is part of a global counter where only the total sum
483 * over all CPUs matters. A task can increase this counter on
484 * one CPU and if it got migrated afterwards it may decrease
485 * it on another CPU. Always updated under the runqueue lock:
487 unsigned long nr_uninterruptible
;
489 struct task_struct
*curr
, *idle
, *stop
;
490 unsigned long next_balance
;
491 struct mm_struct
*prev_mm
;
499 struct root_domain
*rd
;
500 struct sched_domain
*sd
;
502 unsigned long cpu_power
;
504 unsigned char idle_at_tick
;
505 /* For active balancing */
509 struct cpu_stop_work active_balance_work
;
510 /* cpu of this runqueue: */
514 unsigned long avg_load_per_task
;
522 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
526 /* calc_load related fields */
527 unsigned long calc_load_update
;
528 long calc_load_active
;
530 #ifdef CONFIG_SCHED_HRTICK
532 int hrtick_csd_pending
;
533 struct call_single_data hrtick_csd
;
535 struct hrtimer hrtick_timer
;
538 #ifdef CONFIG_SCHEDSTATS
540 struct sched_info rq_sched_info
;
541 unsigned long long rq_cpu_time
;
542 /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
544 /* sys_sched_yield() stats */
545 unsigned int yld_count
;
547 /* schedule() stats */
548 unsigned int sched_switch
;
549 unsigned int sched_count
;
550 unsigned int sched_goidle
;
552 /* try_to_wake_up() stats */
553 unsigned int ttwu_count
;
554 unsigned int ttwu_local
;
558 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
561 static void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int flags
);
563 static inline int cpu_of(struct rq
*rq
)
572 #define rcu_dereference_check_sched_domain(p) \
573 rcu_dereference_check((p), \
574 rcu_read_lock_sched_held() || \
575 lockdep_is_held(&sched_domains_mutex))
578 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
579 * See detach_destroy_domains: synchronize_sched for details.
581 * The domain tree of any CPU may only be accessed from within
582 * preempt-disabled sections.
584 #define for_each_domain(cpu, __sd) \
585 for (__sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
587 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
588 #define this_rq() (&__get_cpu_var(runqueues))
589 #define task_rq(p) cpu_rq(task_cpu(p))
590 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
591 #define raw_rq() (&__raw_get_cpu_var(runqueues))
593 #ifdef CONFIG_CGROUP_SCHED
596 * Return the group to which this tasks belongs.
598 * We use task_subsys_state_check() and extend the RCU verification
599 * with lockdep_is_held(&task_rq(p)->lock) because cpu_cgroup_attach()
600 * holds that lock for each task it moves into the cgroup. Therefore
601 * by holding that lock, we pin the task to the current cgroup.
603 static inline struct task_group
*task_group(struct task_struct
*p
)
605 struct task_group
*tg
;
606 struct cgroup_subsys_state
*css
;
608 css
= task_subsys_state_check(p
, cpu_cgroup_subsys_id
,
609 lockdep_is_held(&task_rq(p
)->lock
));
610 tg
= container_of(css
, struct task_group
, css
);
612 return autogroup_task_group(p
, tg
);
615 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
616 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
)
618 #ifdef CONFIG_FAIR_GROUP_SCHED
619 p
->se
.cfs_rq
= task_group(p
)->cfs_rq
[cpu
];
620 p
->se
.parent
= task_group(p
)->se
[cpu
];
623 #ifdef CONFIG_RT_GROUP_SCHED
624 p
->rt
.rt_rq
= task_group(p
)->rt_rq
[cpu
];
625 p
->rt
.parent
= task_group(p
)->rt_se
[cpu
];
629 #else /* CONFIG_CGROUP_SCHED */
631 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
) { }
632 static inline struct task_group
*task_group(struct task_struct
*p
)
637 #endif /* CONFIG_CGROUP_SCHED */
639 static void update_rq_clock_task(struct rq
*rq
, s64 delta
);
641 static void update_rq_clock(struct rq
*rq
)
645 if (rq
->skip_clock_update
)
648 delta
= sched_clock_cpu(cpu_of(rq
)) - rq
->clock
;
650 update_rq_clock_task(rq
, delta
);
654 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
656 #ifdef CONFIG_SCHED_DEBUG
657 # define const_debug __read_mostly
659 # define const_debug static const
663 * runqueue_is_locked - Returns true if the current cpu runqueue is locked
664 * @cpu: the processor in question.
666 * This interface allows printk to be called with the runqueue lock
667 * held and know whether or not it is OK to wake up the klogd.
669 int runqueue_is_locked(int cpu
)
671 return raw_spin_is_locked(&cpu_rq(cpu
)->lock
);
675 * Debugging: various feature bits
678 #define SCHED_FEAT(name, enabled) \
679 __SCHED_FEAT_##name ,
682 #include "sched_features.h"
687 #define SCHED_FEAT(name, enabled) \
688 (1UL << __SCHED_FEAT_##name) * enabled |
690 const_debug
unsigned int sysctl_sched_features
=
691 #include "sched_features.h"
696 #ifdef CONFIG_SCHED_DEBUG
697 #define SCHED_FEAT(name, enabled) \
700 static __read_mostly
char *sched_feat_names
[] = {
701 #include "sched_features.h"
707 static int sched_feat_show(struct seq_file
*m
, void *v
)
711 for (i
= 0; sched_feat_names
[i
]; i
++) {
712 if (!(sysctl_sched_features
& (1UL << i
)))
714 seq_printf(m
, "%s ", sched_feat_names
[i
]);
722 sched_feat_write(struct file
*filp
, const char __user
*ubuf
,
723 size_t cnt
, loff_t
*ppos
)
733 if (copy_from_user(&buf
, ubuf
, cnt
))
739 if (strncmp(cmp
, "NO_", 3) == 0) {
744 for (i
= 0; sched_feat_names
[i
]; i
++) {
745 if (strcmp(cmp
, sched_feat_names
[i
]) == 0) {
747 sysctl_sched_features
&= ~(1UL << i
);
749 sysctl_sched_features
|= (1UL << i
);
754 if (!sched_feat_names
[i
])
762 static int sched_feat_open(struct inode
*inode
, struct file
*filp
)
764 return single_open(filp
, sched_feat_show
, NULL
);
767 static const struct file_operations sched_feat_fops
= {
768 .open
= sched_feat_open
,
769 .write
= sched_feat_write
,
772 .release
= single_release
,
775 static __init
int sched_init_debug(void)
777 debugfs_create_file("sched_features", 0644, NULL
, NULL
,
782 late_initcall(sched_init_debug
);
786 #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
789 * Number of tasks to iterate in a single balance run.
790 * Limited because this is done with IRQs disabled.
792 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
795 * period over which we average the RT time consumption, measured
800 const_debug
unsigned int sysctl_sched_time_avg
= MSEC_PER_SEC
;
803 * period over which we measure -rt task cpu usage in us.
806 unsigned int sysctl_sched_rt_period
= 1000000;
808 static __read_mostly
int scheduler_running
;
811 * part of the period that we allow rt tasks to run in us.
814 int sysctl_sched_rt_runtime
= 950000;
816 static inline u64
global_rt_period(void)
818 return (u64
)sysctl_sched_rt_period
* NSEC_PER_USEC
;
821 static inline u64
global_rt_runtime(void)
823 if (sysctl_sched_rt_runtime
< 0)
826 return (u64
)sysctl_sched_rt_runtime
* NSEC_PER_USEC
;
829 #ifndef prepare_arch_switch
830 # define prepare_arch_switch(next) do { } while (0)
832 #ifndef finish_arch_switch
833 # define finish_arch_switch(prev) do { } while (0)
836 static inline int task_current(struct rq
*rq
, struct task_struct
*p
)
838 return rq
->curr
== p
;
841 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
846 return task_current(rq
, p
);
850 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
851 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
855 * We can optimise this out completely for !SMP, because the
856 * SMP rebalancing from interrupt is the only thing that cares
863 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
867 * After ->on_cpu is cleared, the task can be moved to a different CPU.
868 * We must ensure this doesn't happen until the switch is completely
874 #ifdef CONFIG_DEBUG_SPINLOCK
875 /* this is a valid case when another task releases the spinlock */
876 rq
->lock
.owner
= current
;
879 * If we are tracking spinlock dependencies then we have to
880 * fix up the runqueue lock - which gets 'carried over' from
883 spin_acquire(&rq
->lock
.dep_map
, 0, 0, _THIS_IP_
);
885 raw_spin_unlock_irq(&rq
->lock
);
888 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
889 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
893 * We can optimise this out completely for !SMP, because the
894 * SMP rebalancing from interrupt is the only thing that cares
899 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
900 raw_spin_unlock_irq(&rq
->lock
);
902 raw_spin_unlock(&rq
->lock
);
906 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
910 * After ->on_cpu is cleared, the task can be moved to a different CPU.
911 * We must ensure this doesn't happen until the switch is completely
917 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
921 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
924 * Check whether the task is waking, we use this to synchronize ->cpus_allowed
927 static inline int task_is_waking(struct task_struct
*p
)
929 return unlikely(p
->state
== TASK_WAKING
);
933 * __task_rq_lock - lock the runqueue a given task resides on.
934 * Must be called interrupts disabled.
936 static inline struct rq
*__task_rq_lock(struct task_struct
*p
)
943 raw_spin_lock(&rq
->lock
);
944 if (likely(rq
== task_rq(p
)))
946 raw_spin_unlock(&rq
->lock
);
951 * task_rq_lock - lock the runqueue a given task resides on and disable
952 * interrupts. Note the ordering: we can safely lookup the task_rq without
953 * explicitly disabling preemption.
955 static struct rq
*task_rq_lock(struct task_struct
*p
, unsigned long *flags
)
961 local_irq_save(*flags
);
963 raw_spin_lock(&rq
->lock
);
964 if (likely(rq
== task_rq(p
)))
966 raw_spin_unlock_irqrestore(&rq
->lock
, *flags
);
970 static void __task_rq_unlock(struct rq
*rq
)
973 raw_spin_unlock(&rq
->lock
);
976 static inline void task_rq_unlock(struct rq
*rq
, unsigned long *flags
)
979 raw_spin_unlock_irqrestore(&rq
->lock
, *flags
);
983 * this_rq_lock - lock this runqueue and disable interrupts.
985 static struct rq
*this_rq_lock(void)
992 raw_spin_lock(&rq
->lock
);
997 #ifdef CONFIG_SCHED_HRTICK
999 * Use HR-timers to deliver accurate preemption points.
1001 * Its all a bit involved since we cannot program an hrt while holding the
1002 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
1005 * When we get rescheduled we reprogram the hrtick_timer outside of the
1011 * - enabled by features
1012 * - hrtimer is actually high res
1014 static inline int hrtick_enabled(struct rq
*rq
)
1016 if (!sched_feat(HRTICK
))
1018 if (!cpu_active(cpu_of(rq
)))
1020 return hrtimer_is_hres_active(&rq
->hrtick_timer
);
1023 static void hrtick_clear(struct rq
*rq
)
1025 if (hrtimer_active(&rq
->hrtick_timer
))
1026 hrtimer_cancel(&rq
->hrtick_timer
);
1030 * High-resolution timer tick.
1031 * Runs from hardirq context with interrupts disabled.
1033 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
1035 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
1037 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1039 raw_spin_lock(&rq
->lock
);
1040 update_rq_clock(rq
);
1041 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
1042 raw_spin_unlock(&rq
->lock
);
1044 return HRTIMER_NORESTART
;
1049 * called from hardirq (IPI) context
1051 static void __hrtick_start(void *arg
)
1053 struct rq
*rq
= arg
;
1055 raw_spin_lock(&rq
->lock
);
1056 hrtimer_restart(&rq
->hrtick_timer
);
1057 rq
->hrtick_csd_pending
= 0;
1058 raw_spin_unlock(&rq
->lock
);
1062 * Called to set the hrtick timer state.
1064 * called with rq->lock held and irqs disabled
1066 static void hrtick_start(struct rq
*rq
, u64 delay
)
1068 struct hrtimer
*timer
= &rq
->hrtick_timer
;
1069 ktime_t time
= ktime_add_ns(timer
->base
->get_time(), delay
);
1071 hrtimer_set_expires(timer
, time
);
1073 if (rq
== this_rq()) {
1074 hrtimer_restart(timer
);
1075 } else if (!rq
->hrtick_csd_pending
) {
1076 __smp_call_function_single(cpu_of(rq
), &rq
->hrtick_csd
, 0);
1077 rq
->hrtick_csd_pending
= 1;
1082 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
1084 int cpu
= (int)(long)hcpu
;
1087 case CPU_UP_CANCELED
:
1088 case CPU_UP_CANCELED_FROZEN
:
1089 case CPU_DOWN_PREPARE
:
1090 case CPU_DOWN_PREPARE_FROZEN
:
1092 case CPU_DEAD_FROZEN
:
1093 hrtick_clear(cpu_rq(cpu
));
1100 static __init
void init_hrtick(void)
1102 hotcpu_notifier(hotplug_hrtick
, 0);
1106 * Called to set the hrtick timer state.
1108 * called with rq->lock held and irqs disabled
1110 static void hrtick_start(struct rq
*rq
, u64 delay
)
1112 __hrtimer_start_range_ns(&rq
->hrtick_timer
, ns_to_ktime(delay
), 0,
1113 HRTIMER_MODE_REL_PINNED
, 0);
1116 static inline void init_hrtick(void)
1119 #endif /* CONFIG_SMP */
1121 static void init_rq_hrtick(struct rq
*rq
)
1124 rq
->hrtick_csd_pending
= 0;
1126 rq
->hrtick_csd
.flags
= 0;
1127 rq
->hrtick_csd
.func
= __hrtick_start
;
1128 rq
->hrtick_csd
.info
= rq
;
1131 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1132 rq
->hrtick_timer
.function
= hrtick
;
1134 #else /* CONFIG_SCHED_HRTICK */
1135 static inline void hrtick_clear(struct rq
*rq
)
1139 static inline void init_rq_hrtick(struct rq
*rq
)
1143 static inline void init_hrtick(void)
1146 #endif /* CONFIG_SCHED_HRTICK */
1149 * resched_task - mark a task 'to be rescheduled now'.
1151 * On UP this means the setting of the need_resched flag, on SMP it
1152 * might also involve a cross-CPU call to trigger the scheduler on
1157 #ifndef tsk_is_polling
1158 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1161 static void resched_task(struct task_struct
*p
)
1165 assert_raw_spin_locked(&task_rq(p
)->lock
);
1167 if (test_tsk_need_resched(p
))
1170 set_tsk_need_resched(p
);
1173 if (cpu
== smp_processor_id())
1176 /* NEED_RESCHED must be visible before we test polling */
1178 if (!tsk_is_polling(p
))
1179 smp_send_reschedule(cpu
);
1182 static void resched_cpu(int cpu
)
1184 struct rq
*rq
= cpu_rq(cpu
);
1185 unsigned long flags
;
1187 if (!raw_spin_trylock_irqsave(&rq
->lock
, flags
))
1189 resched_task(cpu_curr(cpu
));
1190 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
1195 * In the semi idle case, use the nearest busy cpu for migrating timers
1196 * from an idle cpu. This is good for power-savings.
1198 * We don't do similar optimization for completely idle system, as
1199 * selecting an idle cpu will add more delays to the timers than intended
1200 * (as that cpu's timer base may not be uptodate wrt jiffies etc).
1202 int get_nohz_timer_target(void)
1204 int cpu
= smp_processor_id();
1206 struct sched_domain
*sd
;
1208 for_each_domain(cpu
, sd
) {
1209 for_each_cpu(i
, sched_domain_span(sd
))
1216 * When add_timer_on() enqueues a timer into the timer wheel of an
1217 * idle CPU then this timer might expire before the next timer event
1218 * which is scheduled to wake up that CPU. In case of a completely
1219 * idle system the next event might even be infinite time into the
1220 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1221 * leaves the inner idle loop so the newly added timer is taken into
1222 * account when the CPU goes back to idle and evaluates the timer
1223 * wheel for the next timer event.
1225 void wake_up_idle_cpu(int cpu
)
1227 struct rq
*rq
= cpu_rq(cpu
);
1229 if (cpu
== smp_processor_id())
1233 * This is safe, as this function is called with the timer
1234 * wheel base lock of (cpu) held. When the CPU is on the way
1235 * to idle and has not yet set rq->curr to idle then it will
1236 * be serialized on the timer wheel base lock and take the new
1237 * timer into account automatically.
1239 if (rq
->curr
!= rq
->idle
)
1243 * We can set TIF_RESCHED on the idle task of the other CPU
1244 * lockless. The worst case is that the other CPU runs the
1245 * idle task through an additional NOOP schedule()
1247 set_tsk_need_resched(rq
->idle
);
1249 /* NEED_RESCHED must be visible before we test polling */
1251 if (!tsk_is_polling(rq
->idle
))
1252 smp_send_reschedule(cpu
);
1255 #endif /* CONFIG_NO_HZ */
1257 static u64
sched_avg_period(void)
1259 return (u64
)sysctl_sched_time_avg
* NSEC_PER_MSEC
/ 2;
1262 static void sched_avg_update(struct rq
*rq
)
1264 s64 period
= sched_avg_period();
1266 while ((s64
)(rq
->clock
- rq
->age_stamp
) > period
) {
1268 * Inline assembly required to prevent the compiler
1269 * optimising this loop into a divmod call.
1270 * See __iter_div_u64_rem() for another example of this.
1272 asm("" : "+rm" (rq
->age_stamp
));
1273 rq
->age_stamp
+= period
;
1278 static void sched_rt_avg_update(struct rq
*rq
, u64 rt_delta
)
1280 rq
->rt_avg
+= rt_delta
;
1281 sched_avg_update(rq
);
1284 #else /* !CONFIG_SMP */
1285 static void resched_task(struct task_struct
*p
)
1287 assert_raw_spin_locked(&task_rq(p
)->lock
);
1288 set_tsk_need_resched(p
);
1291 static void sched_rt_avg_update(struct rq
*rq
, u64 rt_delta
)
1295 static void sched_avg_update(struct rq
*rq
)
1298 #endif /* CONFIG_SMP */
1300 #if BITS_PER_LONG == 32
1301 # define WMULT_CONST (~0UL)
1303 # define WMULT_CONST (1UL << 32)
1306 #define WMULT_SHIFT 32
1309 * Shift right and round:
1311 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1314 * delta *= weight / lw
1316 static unsigned long
1317 calc_delta_mine(unsigned long delta_exec
, unsigned long weight
,
1318 struct load_weight
*lw
)
1322 if (!lw
->inv_weight
) {
1323 if (BITS_PER_LONG
> 32 && unlikely(lw
->weight
>= WMULT_CONST
))
1326 lw
->inv_weight
= 1 + (WMULT_CONST
-lw
->weight
/2)
1330 tmp
= (u64
)delta_exec
* weight
;
1332 * Check whether we'd overflow the 64-bit multiplication:
1334 if (unlikely(tmp
> WMULT_CONST
))
1335 tmp
= SRR(SRR(tmp
, WMULT_SHIFT
/2) * lw
->inv_weight
,
1338 tmp
= SRR(tmp
* lw
->inv_weight
, WMULT_SHIFT
);
1340 return (unsigned long)min(tmp
, (u64
)(unsigned long)LONG_MAX
);
1343 static inline void update_load_add(struct load_weight
*lw
, unsigned long inc
)
1349 static inline void update_load_sub(struct load_weight
*lw
, unsigned long dec
)
1355 static inline void update_load_set(struct load_weight
*lw
, unsigned long w
)
1362 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1363 * of tasks with abnormal "nice" values across CPUs the contribution that
1364 * each task makes to its run queue's load is weighted according to its
1365 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1366 * scaled version of the new time slice allocation that they receive on time
1370 #define WEIGHT_IDLEPRIO 3
1371 #define WMULT_IDLEPRIO 1431655765
1374 * Nice levels are multiplicative, with a gentle 10% change for every
1375 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1376 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1377 * that remained on nice 0.
1379 * The "10% effect" is relative and cumulative: from _any_ nice level,
1380 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1381 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1382 * If a task goes up by ~10% and another task goes down by ~10% then
1383 * the relative distance between them is ~25%.)
1385 static const int prio_to_weight
[40] = {
1386 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1387 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1388 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1389 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1390 /* 0 */ 1024, 820, 655, 526, 423,
1391 /* 5 */ 335, 272, 215, 172, 137,
1392 /* 10 */ 110, 87, 70, 56, 45,
1393 /* 15 */ 36, 29, 23, 18, 15,
1397 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1399 * In cases where the weight does not change often, we can use the
1400 * precalculated inverse to speed up arithmetics by turning divisions
1401 * into multiplications:
1403 static const u32 prio_to_wmult
[40] = {
1404 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1405 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1406 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1407 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1408 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1409 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1410 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1411 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1414 /* Time spent by the tasks of the cpu accounting group executing in ... */
1415 enum cpuacct_stat_index
{
1416 CPUACCT_STAT_USER
, /* ... user mode */
1417 CPUACCT_STAT_SYSTEM
, /* ... kernel mode */
1419 CPUACCT_STAT_NSTATS
,
1422 #ifdef CONFIG_CGROUP_CPUACCT
1423 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
);
1424 static void cpuacct_update_stats(struct task_struct
*tsk
,
1425 enum cpuacct_stat_index idx
, cputime_t val
);
1427 static inline void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
) {}
1428 static inline void cpuacct_update_stats(struct task_struct
*tsk
,
1429 enum cpuacct_stat_index idx
, cputime_t val
) {}
1432 static inline void inc_cpu_load(struct rq
*rq
, unsigned long load
)
1434 update_load_add(&rq
->load
, load
);
1437 static inline void dec_cpu_load(struct rq
*rq
, unsigned long load
)
1439 update_load_sub(&rq
->load
, load
);
1442 #if (defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)) || defined(CONFIG_RT_GROUP_SCHED)
1443 typedef int (*tg_visitor
)(struct task_group
*, void *);
1446 * Iterate the full tree, calling @down when first entering a node and @up when
1447 * leaving it for the final time.
1449 static int walk_tg_tree(tg_visitor down
, tg_visitor up
, void *data
)
1451 struct task_group
*parent
, *child
;
1455 parent
= &root_task_group
;
1457 ret
= (*down
)(parent
, data
);
1460 list_for_each_entry_rcu(child
, &parent
->children
, siblings
) {
1467 ret
= (*up
)(parent
, data
);
1472 parent
= parent
->parent
;
1481 static int tg_nop(struct task_group
*tg
, void *data
)
1488 /* Used instead of source_load when we know the type == 0 */
1489 static unsigned long weighted_cpuload(const int cpu
)
1491 return cpu_rq(cpu
)->load
.weight
;
1495 * Return a low guess at the load of a migration-source cpu weighted
1496 * according to the scheduling class and "nice" value.
1498 * We want to under-estimate the load of migration sources, to
1499 * balance conservatively.
1501 static unsigned long source_load(int cpu
, int type
)
1503 struct rq
*rq
= cpu_rq(cpu
);
1504 unsigned long total
= weighted_cpuload(cpu
);
1506 if (type
== 0 || !sched_feat(LB_BIAS
))
1509 return min(rq
->cpu_load
[type
-1], total
);
1513 * Return a high guess at the load of a migration-target cpu weighted
1514 * according to the scheduling class and "nice" value.
1516 static unsigned long target_load(int cpu
, int type
)
1518 struct rq
*rq
= cpu_rq(cpu
);
1519 unsigned long total
= weighted_cpuload(cpu
);
1521 if (type
== 0 || !sched_feat(LB_BIAS
))
1524 return max(rq
->cpu_load
[type
-1], total
);
1527 static unsigned long power_of(int cpu
)
1529 return cpu_rq(cpu
)->cpu_power
;
1532 static int task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
);
1534 static unsigned long cpu_avg_load_per_task(int cpu
)
1536 struct rq
*rq
= cpu_rq(cpu
);
1537 unsigned long nr_running
= ACCESS_ONCE(rq
->nr_running
);
1540 rq
->avg_load_per_task
= rq
->load
.weight
/ nr_running
;
1542 rq
->avg_load_per_task
= 0;
1544 return rq
->avg_load_per_task
;
1547 #ifdef CONFIG_FAIR_GROUP_SCHED
1550 * Compute the cpu's hierarchical load factor for each task group.
1551 * This needs to be done in a top-down fashion because the load of a child
1552 * group is a fraction of its parents load.
1554 static int tg_load_down(struct task_group
*tg
, void *data
)
1557 long cpu
= (long)data
;
1560 load
= cpu_rq(cpu
)->load
.weight
;
1562 load
= tg
->parent
->cfs_rq
[cpu
]->h_load
;
1563 load
*= tg
->se
[cpu
]->load
.weight
;
1564 load
/= tg
->parent
->cfs_rq
[cpu
]->load
.weight
+ 1;
1567 tg
->cfs_rq
[cpu
]->h_load
= load
;
1572 static void update_h_load(long cpu
)
1574 walk_tg_tree(tg_load_down
, tg_nop
, (void *)cpu
);
1579 #ifdef CONFIG_PREEMPT
1581 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
);
1584 * fair double_lock_balance: Safely acquires both rq->locks in a fair
1585 * way at the expense of forcing extra atomic operations in all
1586 * invocations. This assures that the double_lock is acquired using the
1587 * same underlying policy as the spinlock_t on this architecture, which
1588 * reduces latency compared to the unfair variant below. However, it
1589 * also adds more overhead and therefore may reduce throughput.
1591 static inline int _double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1592 __releases(this_rq
->lock
)
1593 __acquires(busiest
->lock
)
1594 __acquires(this_rq
->lock
)
1596 raw_spin_unlock(&this_rq
->lock
);
1597 double_rq_lock(this_rq
, busiest
);
1604 * Unfair double_lock_balance: Optimizes throughput at the expense of
1605 * latency by eliminating extra atomic operations when the locks are
1606 * already in proper order on entry. This favors lower cpu-ids and will
1607 * grant the double lock to lower cpus over higher ids under contention,
1608 * regardless of entry order into the function.
1610 static int _double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1611 __releases(this_rq
->lock
)
1612 __acquires(busiest
->lock
)
1613 __acquires(this_rq
->lock
)
1617 if (unlikely(!raw_spin_trylock(&busiest
->lock
))) {
1618 if (busiest
< this_rq
) {
1619 raw_spin_unlock(&this_rq
->lock
);
1620 raw_spin_lock(&busiest
->lock
);
1621 raw_spin_lock_nested(&this_rq
->lock
,
1622 SINGLE_DEPTH_NESTING
);
1625 raw_spin_lock_nested(&busiest
->lock
,
1626 SINGLE_DEPTH_NESTING
);
1631 #endif /* CONFIG_PREEMPT */
1634 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
1636 static int double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1638 if (unlikely(!irqs_disabled())) {
1639 /* printk() doesn't work good under rq->lock */
1640 raw_spin_unlock(&this_rq
->lock
);
1644 return _double_lock_balance(this_rq
, busiest
);
1647 static inline void double_unlock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1648 __releases(busiest
->lock
)
1650 raw_spin_unlock(&busiest
->lock
);
1651 lock_set_subclass(&this_rq
->lock
.dep_map
, 0, _RET_IP_
);
1655 * double_rq_lock - safely lock two runqueues
1657 * Note this does not disable interrupts like task_rq_lock,
1658 * you need to do so manually before calling.
1660 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
)
1661 __acquires(rq1
->lock
)
1662 __acquires(rq2
->lock
)
1664 BUG_ON(!irqs_disabled());
1666 raw_spin_lock(&rq1
->lock
);
1667 __acquire(rq2
->lock
); /* Fake it out ;) */
1670 raw_spin_lock(&rq1
->lock
);
1671 raw_spin_lock_nested(&rq2
->lock
, SINGLE_DEPTH_NESTING
);
1673 raw_spin_lock(&rq2
->lock
);
1674 raw_spin_lock_nested(&rq1
->lock
, SINGLE_DEPTH_NESTING
);
1680 * double_rq_unlock - safely unlock two runqueues
1682 * Note this does not restore interrupts like task_rq_unlock,
1683 * you need to do so manually after calling.
1685 static void double_rq_unlock(struct rq
*rq1
, struct rq
*rq2
)
1686 __releases(rq1
->lock
)
1687 __releases(rq2
->lock
)
1689 raw_spin_unlock(&rq1
->lock
);
1691 raw_spin_unlock(&rq2
->lock
);
1693 __release(rq2
->lock
);
1696 #else /* CONFIG_SMP */
1699 * double_rq_lock - safely lock two runqueues
1701 * Note this does not disable interrupts like task_rq_lock,
1702 * you need to do so manually before calling.
1704 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
)
1705 __acquires(rq1
->lock
)
1706 __acquires(rq2
->lock
)
1708 BUG_ON(!irqs_disabled());
1710 raw_spin_lock(&rq1
->lock
);
1711 __acquire(rq2
->lock
); /* Fake it out ;) */
1715 * double_rq_unlock - safely unlock two runqueues
1717 * Note this does not restore interrupts like task_rq_unlock,
1718 * you need to do so manually after calling.
1720 static void double_rq_unlock(struct rq
*rq1
, struct rq
*rq2
)
1721 __releases(rq1
->lock
)
1722 __releases(rq2
->lock
)
1725 raw_spin_unlock(&rq1
->lock
);
1726 __release(rq2
->lock
);
1731 static void calc_load_account_idle(struct rq
*this_rq
);
1732 static void update_sysctl(void);
1733 static int get_update_sysctl_factor(void);
1734 static void update_cpu_load(struct rq
*this_rq
);
1736 static inline void __set_task_cpu(struct task_struct
*p
, unsigned int cpu
)
1738 set_task_rq(p
, cpu
);
1741 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1742 * successfuly executed on another CPU. We must ensure that updates of
1743 * per-task data have been completed by this moment.
1746 task_thread_info(p
)->cpu
= cpu
;
1750 static const struct sched_class rt_sched_class
;
1752 #define sched_class_highest (&stop_sched_class)
1753 #define for_each_class(class) \
1754 for (class = sched_class_highest; class; class = class->next)
1756 #include "sched_stats.h"
1758 static void inc_nr_running(struct rq
*rq
)
1763 static void dec_nr_running(struct rq
*rq
)
1768 static void set_load_weight(struct task_struct
*p
)
1771 * SCHED_IDLE tasks get minimal weight:
1773 if (p
->policy
== SCHED_IDLE
) {
1774 p
->se
.load
.weight
= WEIGHT_IDLEPRIO
;
1775 p
->se
.load
.inv_weight
= WMULT_IDLEPRIO
;
1779 p
->se
.load
.weight
= prio_to_weight
[p
->static_prio
- MAX_RT_PRIO
];
1780 p
->se
.load
.inv_weight
= prio_to_wmult
[p
->static_prio
- MAX_RT_PRIO
];
1783 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
1785 update_rq_clock(rq
);
1786 sched_info_queued(p
);
1787 p
->sched_class
->enqueue_task(rq
, p
, flags
);
1791 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
1793 update_rq_clock(rq
);
1794 sched_info_dequeued(p
);
1795 p
->sched_class
->dequeue_task(rq
, p
, flags
);
1800 * activate_task - move a task to the runqueue.
1802 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
1804 if (task_contributes_to_load(p
))
1805 rq
->nr_uninterruptible
--;
1807 enqueue_task(rq
, p
, flags
);
1812 * deactivate_task - remove a task from the runqueue.
1814 static void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
1816 if (task_contributes_to_load(p
))
1817 rq
->nr_uninterruptible
++;
1819 dequeue_task(rq
, p
, flags
);
1823 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
1826 * There are no locks covering percpu hardirq/softirq time.
1827 * They are only modified in account_system_vtime, on corresponding CPU
1828 * with interrupts disabled. So, writes are safe.
1829 * They are read and saved off onto struct rq in update_rq_clock().
1830 * This may result in other CPU reading this CPU's irq time and can
1831 * race with irq/account_system_vtime on this CPU. We would either get old
1832 * or new value with a side effect of accounting a slice of irq time to wrong
1833 * task when irq is in progress while we read rq->clock. That is a worthy
1834 * compromise in place of having locks on each irq in account_system_time.
1836 static DEFINE_PER_CPU(u64
, cpu_hardirq_time
);
1837 static DEFINE_PER_CPU(u64
, cpu_softirq_time
);
1839 static DEFINE_PER_CPU(u64
, irq_start_time
);
1840 static int sched_clock_irqtime
;
1842 void enable_sched_clock_irqtime(void)
1844 sched_clock_irqtime
= 1;
1847 void disable_sched_clock_irqtime(void)
1849 sched_clock_irqtime
= 0;
1852 #ifndef CONFIG_64BIT
1853 static DEFINE_PER_CPU(seqcount_t
, irq_time_seq
);
1855 static inline void irq_time_write_begin(void)
1857 __this_cpu_inc(irq_time_seq
.sequence
);
1861 static inline void irq_time_write_end(void)
1864 __this_cpu_inc(irq_time_seq
.sequence
);
1867 static inline u64
irq_time_read(int cpu
)
1873 seq
= read_seqcount_begin(&per_cpu(irq_time_seq
, cpu
));
1874 irq_time
= per_cpu(cpu_softirq_time
, cpu
) +
1875 per_cpu(cpu_hardirq_time
, cpu
);
1876 } while (read_seqcount_retry(&per_cpu(irq_time_seq
, cpu
), seq
));
1880 #else /* CONFIG_64BIT */
1881 static inline void irq_time_write_begin(void)
1885 static inline void irq_time_write_end(void)
1889 static inline u64
irq_time_read(int cpu
)
1891 return per_cpu(cpu_softirq_time
, cpu
) + per_cpu(cpu_hardirq_time
, cpu
);
1893 #endif /* CONFIG_64BIT */
1896 * Called before incrementing preempt_count on {soft,}irq_enter
1897 * and before decrementing preempt_count on {soft,}irq_exit.
1899 void account_system_vtime(struct task_struct
*curr
)
1901 unsigned long flags
;
1905 if (!sched_clock_irqtime
)
1908 local_irq_save(flags
);
1910 cpu
= smp_processor_id();
1911 delta
= sched_clock_cpu(cpu
) - __this_cpu_read(irq_start_time
);
1912 __this_cpu_add(irq_start_time
, delta
);
1914 irq_time_write_begin();
1916 * We do not account for softirq time from ksoftirqd here.
1917 * We want to continue accounting softirq time to ksoftirqd thread
1918 * in that case, so as not to confuse scheduler with a special task
1919 * that do not consume any time, but still wants to run.
1921 if (hardirq_count())
1922 __this_cpu_add(cpu_hardirq_time
, delta
);
1923 else if (in_serving_softirq() && curr
!= this_cpu_ksoftirqd())
1924 __this_cpu_add(cpu_softirq_time
, delta
);
1926 irq_time_write_end();
1927 local_irq_restore(flags
);
1929 EXPORT_SYMBOL_GPL(account_system_vtime
);
1931 static void update_rq_clock_task(struct rq
*rq
, s64 delta
)
1935 irq_delta
= irq_time_read(cpu_of(rq
)) - rq
->prev_irq_time
;
1938 * Since irq_time is only updated on {soft,}irq_exit, we might run into
1939 * this case when a previous update_rq_clock() happened inside a
1940 * {soft,}irq region.
1942 * When this happens, we stop ->clock_task and only update the
1943 * prev_irq_time stamp to account for the part that fit, so that a next
1944 * update will consume the rest. This ensures ->clock_task is
1947 * It does however cause some slight miss-attribution of {soft,}irq
1948 * time, a more accurate solution would be to update the irq_time using
1949 * the current rq->clock timestamp, except that would require using
1952 if (irq_delta
> delta
)
1955 rq
->prev_irq_time
+= irq_delta
;
1957 rq
->clock_task
+= delta
;
1959 if (irq_delta
&& sched_feat(NONIRQ_POWER
))
1960 sched_rt_avg_update(rq
, irq_delta
);
1963 static int irqtime_account_hi_update(void)
1965 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
1966 unsigned long flags
;
1970 local_irq_save(flags
);
1971 latest_ns
= this_cpu_read(cpu_hardirq_time
);
1972 if (cputime64_gt(nsecs_to_cputime64(latest_ns
), cpustat
->irq
))
1974 local_irq_restore(flags
);
1978 static int irqtime_account_si_update(void)
1980 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
1981 unsigned long flags
;
1985 local_irq_save(flags
);
1986 latest_ns
= this_cpu_read(cpu_softirq_time
);
1987 if (cputime64_gt(nsecs_to_cputime64(latest_ns
), cpustat
->softirq
))
1989 local_irq_restore(flags
);
1993 #else /* CONFIG_IRQ_TIME_ACCOUNTING */
1995 #define sched_clock_irqtime (0)
1997 static void update_rq_clock_task(struct rq
*rq
, s64 delta
)
1999 rq
->clock_task
+= delta
;
2002 #endif /* CONFIG_IRQ_TIME_ACCOUNTING */
2004 #include "sched_idletask.c"
2005 #include "sched_fair.c"
2006 #include "sched_rt.c"
2007 #include "sched_autogroup.c"
2008 #include "sched_stoptask.c"
2009 #ifdef CONFIG_SCHED_DEBUG
2010 # include "sched_debug.c"
2013 void sched_set_stop_task(int cpu
, struct task_struct
*stop
)
2015 struct sched_param param
= { .sched_priority
= MAX_RT_PRIO
- 1 };
2016 struct task_struct
*old_stop
= cpu_rq(cpu
)->stop
;
2020 * Make it appear like a SCHED_FIFO task, its something
2021 * userspace knows about and won't get confused about.
2023 * Also, it will make PI more or less work without too
2024 * much confusion -- but then, stop work should not
2025 * rely on PI working anyway.
2027 sched_setscheduler_nocheck(stop
, SCHED_FIFO
, ¶m
);
2029 stop
->sched_class
= &stop_sched_class
;
2032 cpu_rq(cpu
)->stop
= stop
;
2036 * Reset it back to a normal scheduling class so that
2037 * it can die in pieces.
2039 old_stop
->sched_class
= &rt_sched_class
;
2044 * __normal_prio - return the priority that is based on the static prio
2046 static inline int __normal_prio(struct task_struct
*p
)
2048 return p
->static_prio
;
2052 * Calculate the expected normal priority: i.e. priority
2053 * without taking RT-inheritance into account. Might be
2054 * boosted by interactivity modifiers. Changes upon fork,
2055 * setprio syscalls, and whenever the interactivity
2056 * estimator recalculates.
2058 static inline int normal_prio(struct task_struct
*p
)
2062 if (task_has_rt_policy(p
))
2063 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
2065 prio
= __normal_prio(p
);
2070 * Calculate the current priority, i.e. the priority
2071 * taken into account by the scheduler. This value might
2072 * be boosted by RT tasks, or might be boosted by
2073 * interactivity modifiers. Will be RT if the task got
2074 * RT-boosted. If not then it returns p->normal_prio.
2076 static int effective_prio(struct task_struct
*p
)
2078 p
->normal_prio
= normal_prio(p
);
2080 * If we are RT tasks or we were boosted to RT priority,
2081 * keep the priority unchanged. Otherwise, update priority
2082 * to the normal priority:
2084 if (!rt_prio(p
->prio
))
2085 return p
->normal_prio
;
2090 * task_curr - is this task currently executing on a CPU?
2091 * @p: the task in question.
2093 inline int task_curr(const struct task_struct
*p
)
2095 return cpu_curr(task_cpu(p
)) == p
;
2098 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
2099 const struct sched_class
*prev_class
,
2102 if (prev_class
!= p
->sched_class
) {
2103 if (prev_class
->switched_from
)
2104 prev_class
->switched_from(rq
, p
);
2105 p
->sched_class
->switched_to(rq
, p
);
2106 } else if (oldprio
!= p
->prio
)
2107 p
->sched_class
->prio_changed(rq
, p
, oldprio
);
2110 static void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int flags
)
2112 const struct sched_class
*class;
2114 if (p
->sched_class
== rq
->curr
->sched_class
) {
2115 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
, flags
);
2117 for_each_class(class) {
2118 if (class == rq
->curr
->sched_class
)
2120 if (class == p
->sched_class
) {
2121 resched_task(rq
->curr
);
2128 * A queue event has occurred, and we're going to schedule. In
2129 * this case, we can save a useless back to back clock update.
2131 if (rq
->curr
->se
.on_rq
&& test_tsk_need_resched(rq
->curr
))
2132 rq
->skip_clock_update
= 1;
2137 * Is this task likely cache-hot:
2140 task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
)
2144 if (p
->sched_class
!= &fair_sched_class
)
2147 if (unlikely(p
->policy
== SCHED_IDLE
))
2151 * Buddy candidates are cache hot:
2153 if (sched_feat(CACHE_HOT_BUDDY
) && this_rq()->nr_running
&&
2154 (&p
->se
== cfs_rq_of(&p
->se
)->next
||
2155 &p
->se
== cfs_rq_of(&p
->se
)->last
))
2158 if (sysctl_sched_migration_cost
== -1)
2160 if (sysctl_sched_migration_cost
== 0)
2163 delta
= now
- p
->se
.exec_start
;
2165 return delta
< (s64
)sysctl_sched_migration_cost
;
2168 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
2170 #ifdef CONFIG_SCHED_DEBUG
2172 * We should never call set_task_cpu() on a blocked task,
2173 * ttwu() will sort out the placement.
2175 WARN_ON_ONCE(p
->state
!= TASK_RUNNING
&& p
->state
!= TASK_WAKING
&&
2176 !(task_thread_info(p
)->preempt_count
& PREEMPT_ACTIVE
));
2179 trace_sched_migrate_task(p
, new_cpu
);
2181 if (task_cpu(p
) != new_cpu
) {
2182 p
->se
.nr_migrations
++;
2183 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS
, 1, 1, NULL
, 0);
2186 __set_task_cpu(p
, new_cpu
);
2189 struct migration_arg
{
2190 struct task_struct
*task
;
2194 static int migration_cpu_stop(void *data
);
2197 * The task's runqueue lock must be held.
2198 * Returns true if you have to wait for migration thread.
2200 static bool migrate_task(struct task_struct
*p
, struct rq
*rq
)
2203 * If the task is not on a runqueue (and not running), then
2204 * the next wake-up will properly place the task.
2206 return p
->se
.on_rq
|| task_running(rq
, p
);
2210 * wait_task_inactive - wait for a thread to unschedule.
2212 * If @match_state is nonzero, it's the @p->state value just checked and
2213 * not expected to change. If it changes, i.e. @p might have woken up,
2214 * then return zero. When we succeed in waiting for @p to be off its CPU,
2215 * we return a positive number (its total switch count). If a second call
2216 * a short while later returns the same number, the caller can be sure that
2217 * @p has remained unscheduled the whole time.
2219 * The caller must ensure that the task *will* unschedule sometime soon,
2220 * else this function might spin for a *long* time. This function can't
2221 * be called with interrupts off, or it may introduce deadlock with
2222 * smp_call_function() if an IPI is sent by the same process we are
2223 * waiting to become inactive.
2225 unsigned long wait_task_inactive(struct task_struct
*p
, long match_state
)
2227 unsigned long flags
;
2234 * We do the initial early heuristics without holding
2235 * any task-queue locks at all. We'll only try to get
2236 * the runqueue lock when things look like they will
2242 * If the task is actively running on another CPU
2243 * still, just relax and busy-wait without holding
2246 * NOTE! Since we don't hold any locks, it's not
2247 * even sure that "rq" stays as the right runqueue!
2248 * But we don't care, since "task_running()" will
2249 * return false if the runqueue has changed and p
2250 * is actually now running somewhere else!
2252 while (task_running(rq
, p
)) {
2253 if (match_state
&& unlikely(p
->state
!= match_state
))
2259 * Ok, time to look more closely! We need the rq
2260 * lock now, to be *sure*. If we're wrong, we'll
2261 * just go back and repeat.
2263 rq
= task_rq_lock(p
, &flags
);
2264 trace_sched_wait_task(p
);
2265 running
= task_running(rq
, p
);
2266 on_rq
= p
->se
.on_rq
;
2268 if (!match_state
|| p
->state
== match_state
)
2269 ncsw
= p
->nvcsw
| LONG_MIN
; /* sets MSB */
2270 task_rq_unlock(rq
, &flags
);
2273 * If it changed from the expected state, bail out now.
2275 if (unlikely(!ncsw
))
2279 * Was it really running after all now that we
2280 * checked with the proper locks actually held?
2282 * Oops. Go back and try again..
2284 if (unlikely(running
)) {
2290 * It's not enough that it's not actively running,
2291 * it must be off the runqueue _entirely_, and not
2294 * So if it was still runnable (but just not actively
2295 * running right now), it's preempted, and we should
2296 * yield - it could be a while.
2298 if (unlikely(on_rq
)) {
2299 ktime_t to
= ktime_set(0, NSEC_PER_SEC
/HZ
);
2301 set_current_state(TASK_UNINTERRUPTIBLE
);
2302 schedule_hrtimeout(&to
, HRTIMER_MODE_REL
);
2307 * Ahh, all good. It wasn't running, and it wasn't
2308 * runnable, which means that it will never become
2309 * running in the future either. We're all done!
2318 * kick_process - kick a running thread to enter/exit the kernel
2319 * @p: the to-be-kicked thread
2321 * Cause a process which is running on another CPU to enter
2322 * kernel-mode, without any delay. (to get signals handled.)
2324 * NOTE: this function doesn't have to take the runqueue lock,
2325 * because all it wants to ensure is that the remote task enters
2326 * the kernel. If the IPI races and the task has been migrated
2327 * to another CPU then no harm is done and the purpose has been
2330 void kick_process(struct task_struct
*p
)
2336 if ((cpu
!= smp_processor_id()) && task_curr(p
))
2337 smp_send_reschedule(cpu
);
2340 EXPORT_SYMBOL_GPL(kick_process
);
2341 #endif /* CONFIG_SMP */
2345 * ->cpus_allowed is protected by either TASK_WAKING or rq->lock held.
2347 static int select_fallback_rq(int cpu
, struct task_struct
*p
)
2350 const struct cpumask
*nodemask
= cpumask_of_node(cpu_to_node(cpu
));
2352 /* Look for allowed, online CPU in same node. */
2353 for_each_cpu_and(dest_cpu
, nodemask
, cpu_active_mask
)
2354 if (cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
2357 /* Any allowed, online CPU? */
2358 dest_cpu
= cpumask_any_and(&p
->cpus_allowed
, cpu_active_mask
);
2359 if (dest_cpu
< nr_cpu_ids
)
2362 /* No more Mr. Nice Guy. */
2363 dest_cpu
= cpuset_cpus_allowed_fallback(p
);
2365 * Don't tell them about moving exiting tasks or
2366 * kernel threads (both mm NULL), since they never
2369 if (p
->mm
&& printk_ratelimit()) {
2370 printk(KERN_INFO
"process %d (%s) no longer affine to cpu%d\n",
2371 task_pid_nr(p
), p
->comm
, cpu
);
2378 * The caller (fork, wakeup) owns TASK_WAKING, ->cpus_allowed is stable.
2381 int select_task_rq(struct rq
*rq
, struct task_struct
*p
, int sd_flags
, int wake_flags
)
2383 int cpu
= p
->sched_class
->select_task_rq(rq
, p
, sd_flags
, wake_flags
);
2386 * In order not to call set_task_cpu() on a blocking task we need
2387 * to rely on ttwu() to place the task on a valid ->cpus_allowed
2390 * Since this is common to all placement strategies, this lives here.
2392 * [ this allows ->select_task() to simply return task_cpu(p) and
2393 * not worry about this generic constraint ]
2395 if (unlikely(!cpumask_test_cpu(cpu
, &p
->cpus_allowed
) ||
2397 cpu
= select_fallback_rq(task_cpu(p
), p
);
2402 static void update_avg(u64
*avg
, u64 sample
)
2404 s64 diff
= sample
- *avg
;
2409 static inline void ttwu_activate(struct task_struct
*p
, struct rq
*rq
,
2410 bool is_sync
, bool is_migrate
, bool is_local
,
2411 unsigned long en_flags
)
2413 schedstat_inc(p
, se
.statistics
.nr_wakeups
);
2415 schedstat_inc(p
, se
.statistics
.nr_wakeups_sync
);
2417 schedstat_inc(p
, se
.statistics
.nr_wakeups_migrate
);
2419 schedstat_inc(p
, se
.statistics
.nr_wakeups_local
);
2421 schedstat_inc(p
, se
.statistics
.nr_wakeups_remote
);
2423 activate_task(rq
, p
, en_flags
);
2426 static inline void ttwu_post_activation(struct task_struct
*p
, struct rq
*rq
,
2427 int wake_flags
, bool success
)
2429 trace_sched_wakeup(p
, success
);
2430 check_preempt_curr(rq
, p
, wake_flags
);
2432 p
->state
= TASK_RUNNING
;
2434 if (p
->sched_class
->task_woken
)
2435 p
->sched_class
->task_woken(rq
, p
);
2437 if (unlikely(rq
->idle_stamp
)) {
2438 u64 delta
= rq
->clock
- rq
->idle_stamp
;
2439 u64 max
= 2*sysctl_sched_migration_cost
;
2444 update_avg(&rq
->avg_idle
, delta
);
2448 /* if a worker is waking up, notify workqueue */
2449 if ((p
->flags
& PF_WQ_WORKER
) && success
)
2450 wq_worker_waking_up(p
, cpu_of(rq
));
2454 * try_to_wake_up - wake up a thread
2455 * @p: the thread to be awakened
2456 * @state: the mask of task states that can be woken
2457 * @wake_flags: wake modifier flags (WF_*)
2459 * Put it on the run-queue if it's not already there. The "current"
2460 * thread is always on the run-queue (except when the actual
2461 * re-schedule is in progress), and as such you're allowed to do
2462 * the simpler "current->state = TASK_RUNNING" to mark yourself
2463 * runnable without the overhead of this.
2465 * Returns %true if @p was woken up, %false if it was already running
2466 * or @state didn't match @p's state.
2468 static int try_to_wake_up(struct task_struct
*p
, unsigned int state
,
2471 int cpu
, orig_cpu
, this_cpu
, success
= 0;
2472 unsigned long flags
;
2473 unsigned long en_flags
= ENQUEUE_WAKEUP
;
2476 this_cpu
= get_cpu();
2479 rq
= task_rq_lock(p
, &flags
);
2480 if (!(p
->state
& state
))
2490 if (unlikely(task_running(rq
, p
)))
2494 * In order to handle concurrent wakeups and release the rq->lock
2495 * we put the task in TASK_WAKING state.
2497 * First fix up the nr_uninterruptible count:
2499 if (task_contributes_to_load(p
)) {
2500 if (likely(cpu_online(orig_cpu
)))
2501 rq
->nr_uninterruptible
--;
2503 this_rq()->nr_uninterruptible
--;
2505 p
->state
= TASK_WAKING
;
2507 if (p
->sched_class
->task_waking
) {
2508 p
->sched_class
->task_waking(rq
, p
);
2509 en_flags
|= ENQUEUE_WAKING
;
2512 cpu
= select_task_rq(rq
, p
, SD_BALANCE_WAKE
, wake_flags
);
2513 if (cpu
!= orig_cpu
)
2514 set_task_cpu(p
, cpu
);
2515 __task_rq_unlock(rq
);
2518 raw_spin_lock(&rq
->lock
);
2521 * We migrated the task without holding either rq->lock, however
2522 * since the task is not on the task list itself, nobody else
2523 * will try and migrate the task, hence the rq should match the
2524 * cpu we just moved it to.
2526 WARN_ON(task_cpu(p
) != cpu
);
2527 WARN_ON(p
->state
!= TASK_WAKING
);
2529 #ifdef CONFIG_SCHEDSTATS
2530 schedstat_inc(rq
, ttwu_count
);
2531 if (cpu
== this_cpu
)
2532 schedstat_inc(rq
, ttwu_local
);
2534 struct sched_domain
*sd
;
2535 for_each_domain(this_cpu
, sd
) {
2536 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
2537 schedstat_inc(sd
, ttwu_wake_remote
);
2542 #endif /* CONFIG_SCHEDSTATS */
2545 #endif /* CONFIG_SMP */
2546 ttwu_activate(p
, rq
, wake_flags
& WF_SYNC
, orig_cpu
!= cpu
,
2547 cpu
== this_cpu
, en_flags
);
2550 ttwu_post_activation(p
, rq
, wake_flags
, success
);
2552 task_rq_unlock(rq
, &flags
);
2559 * try_to_wake_up_local - try to wake up a local task with rq lock held
2560 * @p: the thread to be awakened
2562 * Put @p on the run-queue if it's not already there. The caller must
2563 * ensure that this_rq() is locked, @p is bound to this_rq() and not
2564 * the current task. this_rq() stays locked over invocation.
2566 static void try_to_wake_up_local(struct task_struct
*p
)
2568 struct rq
*rq
= task_rq(p
);
2569 bool success
= false;
2571 BUG_ON(rq
!= this_rq());
2572 BUG_ON(p
== current
);
2573 lockdep_assert_held(&rq
->lock
);
2575 if (!(p
->state
& TASK_NORMAL
))
2579 if (likely(!task_running(rq
, p
))) {
2580 schedstat_inc(rq
, ttwu_count
);
2581 schedstat_inc(rq
, ttwu_local
);
2583 ttwu_activate(p
, rq
, false, false, true, ENQUEUE_WAKEUP
);
2586 ttwu_post_activation(p
, rq
, 0, success
);
2590 * wake_up_process - Wake up a specific process
2591 * @p: The process to be woken up.
2593 * Attempt to wake up the nominated process and move it to the set of runnable
2594 * processes. Returns 1 if the process was woken up, 0 if it was already
2597 * It may be assumed that this function implies a write memory barrier before
2598 * changing the task state if and only if any tasks are woken up.
2600 int wake_up_process(struct task_struct
*p
)
2602 return try_to_wake_up(p
, TASK_ALL
, 0);
2604 EXPORT_SYMBOL(wake_up_process
);
2606 int wake_up_state(struct task_struct
*p
, unsigned int state
)
2608 return try_to_wake_up(p
, state
, 0);
2612 * Perform scheduler related setup for a newly forked process p.
2613 * p is forked by current.
2615 * __sched_fork() is basic setup used by init_idle() too:
2617 static void __sched_fork(struct task_struct
*p
)
2619 p
->se
.exec_start
= 0;
2620 p
->se
.sum_exec_runtime
= 0;
2621 p
->se
.prev_sum_exec_runtime
= 0;
2622 p
->se
.nr_migrations
= 0;
2625 #ifdef CONFIG_SCHEDSTATS
2626 memset(&p
->se
.statistics
, 0, sizeof(p
->se
.statistics
));
2629 INIT_LIST_HEAD(&p
->rt
.run_list
);
2631 INIT_LIST_HEAD(&p
->se
.group_node
);
2633 #ifdef CONFIG_PREEMPT_NOTIFIERS
2634 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
2639 * fork()/clone()-time setup:
2641 void sched_fork(struct task_struct
*p
, int clone_flags
)
2643 int cpu
= get_cpu();
2647 * We mark the process as running here. This guarantees that
2648 * nobody will actually run it, and a signal or other external
2649 * event cannot wake it up and insert it on the runqueue either.
2651 p
->state
= TASK_RUNNING
;
2654 * Revert to default priority/policy on fork if requested.
2656 if (unlikely(p
->sched_reset_on_fork
)) {
2657 if (p
->policy
== SCHED_FIFO
|| p
->policy
== SCHED_RR
) {
2658 p
->policy
= SCHED_NORMAL
;
2659 p
->normal_prio
= p
->static_prio
;
2662 if (PRIO_TO_NICE(p
->static_prio
) < 0) {
2663 p
->static_prio
= NICE_TO_PRIO(0);
2664 p
->normal_prio
= p
->static_prio
;
2669 * We don't need the reset flag anymore after the fork. It has
2670 * fulfilled its duty:
2672 p
->sched_reset_on_fork
= 0;
2676 * Make sure we do not leak PI boosting priority to the child.
2678 p
->prio
= current
->normal_prio
;
2680 if (!rt_prio(p
->prio
))
2681 p
->sched_class
= &fair_sched_class
;
2683 if (p
->sched_class
->task_fork
)
2684 p
->sched_class
->task_fork(p
);
2687 * The child is not yet in the pid-hash so no cgroup attach races,
2688 * and the cgroup is pinned to this child due to cgroup_fork()
2689 * is ran before sched_fork().
2691 * Silence PROVE_RCU.
2694 set_task_cpu(p
, cpu
);
2697 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2698 if (likely(sched_info_on()))
2699 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
2701 #if defined(CONFIG_SMP)
2704 #ifdef CONFIG_PREEMPT
2705 /* Want to start with kernel preemption disabled. */
2706 task_thread_info(p
)->preempt_count
= 1;
2709 plist_node_init(&p
->pushable_tasks
, MAX_PRIO
);
2716 * wake_up_new_task - wake up a newly created task for the first time.
2718 * This function will do some initial scheduler statistics housekeeping
2719 * that must be done for every newly created context, then puts the task
2720 * on the runqueue and wakes it.
2722 void wake_up_new_task(struct task_struct
*p
, unsigned long clone_flags
)
2724 unsigned long flags
;
2726 int cpu __maybe_unused
= get_cpu();
2729 rq
= task_rq_lock(p
, &flags
);
2730 p
->state
= TASK_WAKING
;
2733 * Fork balancing, do it here and not earlier because:
2734 * - cpus_allowed can change in the fork path
2735 * - any previously selected cpu might disappear through hotplug
2737 * We set TASK_WAKING so that select_task_rq() can drop rq->lock
2738 * without people poking at ->cpus_allowed.
2740 cpu
= select_task_rq(rq
, p
, SD_BALANCE_FORK
, 0);
2741 set_task_cpu(p
, cpu
);
2743 p
->state
= TASK_RUNNING
;
2744 task_rq_unlock(rq
, &flags
);
2747 rq
= task_rq_lock(p
, &flags
);
2748 activate_task(rq
, p
, 0);
2749 trace_sched_wakeup_new(p
, 1);
2750 check_preempt_curr(rq
, p
, WF_FORK
);
2752 if (p
->sched_class
->task_woken
)
2753 p
->sched_class
->task_woken(rq
, p
);
2755 task_rq_unlock(rq
, &flags
);
2759 #ifdef CONFIG_PREEMPT_NOTIFIERS
2762 * preempt_notifier_register - tell me when current is being preempted & rescheduled
2763 * @notifier: notifier struct to register
2765 void preempt_notifier_register(struct preempt_notifier
*notifier
)
2767 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
2769 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
2772 * preempt_notifier_unregister - no longer interested in preemption notifications
2773 * @notifier: notifier struct to unregister
2775 * This is safe to call from within a preemption notifier.
2777 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
2779 hlist_del(¬ifier
->link
);
2781 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
2783 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
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_in(notifier
, raw_smp_processor_id());
2793 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2794 struct task_struct
*next
)
2796 struct preempt_notifier
*notifier
;
2797 struct hlist_node
*node
;
2799 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2800 notifier
->ops
->sched_out(notifier
, next
);
2803 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2805 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2810 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2811 struct task_struct
*next
)
2815 #endif /* CONFIG_PREEMPT_NOTIFIERS */
2818 * prepare_task_switch - prepare to switch tasks
2819 * @rq: the runqueue preparing to switch
2820 * @prev: the current task that is being switched out
2821 * @next: the task we are going to switch to.
2823 * This is called with the rq lock held and interrupts off. It must
2824 * be paired with a subsequent finish_task_switch after the context
2827 * prepare_task_switch sets up locking and calls architecture specific
2831 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
2832 struct task_struct
*next
)
2834 sched_info_switch(prev
, next
);
2835 perf_event_task_sched_out(prev
, next
);
2836 fire_sched_out_preempt_notifiers(prev
, next
);
2837 prepare_lock_switch(rq
, next
);
2838 prepare_arch_switch(next
);
2839 trace_sched_switch(prev
, next
);
2843 * finish_task_switch - clean up after a task-switch
2844 * @rq: runqueue associated with task-switch
2845 * @prev: the thread we just switched away from.
2847 * finish_task_switch must be called after the context switch, paired
2848 * with a prepare_task_switch call before the context switch.
2849 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2850 * and do any other architecture-specific cleanup actions.
2852 * Note that we may have delayed dropping an mm in context_switch(). If
2853 * so, we finish that here outside of the runqueue lock. (Doing it
2854 * with the lock held can cause deadlocks; see schedule() for
2857 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
2858 __releases(rq
->lock
)
2860 struct mm_struct
*mm
= rq
->prev_mm
;
2866 * A task struct has one reference for the use as "current".
2867 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2868 * schedule one last time. The schedule call will never return, and
2869 * the scheduled task must drop that reference.
2870 * The test for TASK_DEAD must occur while the runqueue locks are
2871 * still held, otherwise prev could be scheduled on another cpu, die
2872 * there before we look at prev->state, and then the reference would
2874 * Manfred Spraul <manfred@colorfullife.com>
2876 prev_state
= prev
->state
;
2877 finish_arch_switch(prev
);
2878 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
2879 local_irq_disable();
2880 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
2881 perf_event_task_sched_in(current
);
2882 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
2884 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
2885 finish_lock_switch(rq
, prev
);
2887 fire_sched_in_preempt_notifiers(current
);
2890 if (unlikely(prev_state
== TASK_DEAD
)) {
2892 * Remove function-return probe instances associated with this
2893 * task and put them back on the free list.
2895 kprobe_flush_task(prev
);
2896 put_task_struct(prev
);
2902 /* assumes rq->lock is held */
2903 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*prev
)
2905 if (prev
->sched_class
->pre_schedule
)
2906 prev
->sched_class
->pre_schedule(rq
, prev
);
2909 /* rq->lock is NOT held, but preemption is disabled */
2910 static inline void post_schedule(struct rq
*rq
)
2912 if (rq
->post_schedule
) {
2913 unsigned long flags
;
2915 raw_spin_lock_irqsave(&rq
->lock
, flags
);
2916 if (rq
->curr
->sched_class
->post_schedule
)
2917 rq
->curr
->sched_class
->post_schedule(rq
);
2918 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
2920 rq
->post_schedule
= 0;
2926 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*p
)
2930 static inline void post_schedule(struct rq
*rq
)
2937 * schedule_tail - first thing a freshly forked thread must call.
2938 * @prev: the thread we just switched away from.
2940 asmlinkage
void schedule_tail(struct task_struct
*prev
)
2941 __releases(rq
->lock
)
2943 struct rq
*rq
= this_rq();
2945 finish_task_switch(rq
, prev
);
2948 * FIXME: do we need to worry about rq being invalidated by the
2953 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2954 /* In this case, finish_task_switch does not reenable preemption */
2957 if (current
->set_child_tid
)
2958 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2962 * context_switch - switch to the new MM and the new
2963 * thread's register state.
2966 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2967 struct task_struct
*next
)
2969 struct mm_struct
*mm
, *oldmm
;
2971 prepare_task_switch(rq
, prev
, next
);
2974 oldmm
= prev
->active_mm
;
2976 * For paravirt, this is coupled with an exit in switch_to to
2977 * combine the page table reload and the switch backend into
2980 arch_start_context_switch(prev
);
2983 next
->active_mm
= oldmm
;
2984 atomic_inc(&oldmm
->mm_count
);
2985 enter_lazy_tlb(oldmm
, next
);
2987 switch_mm(oldmm
, mm
, next
);
2990 prev
->active_mm
= NULL
;
2991 rq
->prev_mm
= oldmm
;
2994 * Since the runqueue lock will be released by the next
2995 * task (which is an invalid locking op but in the case
2996 * of the scheduler it's an obvious special-case), so we
2997 * do an early lockdep release here:
2999 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
3000 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
3003 /* Here we just switch the register state and the stack. */
3004 switch_to(prev
, next
, prev
);
3008 * this_rq must be evaluated again because prev may have moved
3009 * CPUs since it called schedule(), thus the 'rq' on its stack
3010 * frame will be invalid.
3012 finish_task_switch(this_rq(), prev
);
3016 * nr_running, nr_uninterruptible and nr_context_switches:
3018 * externally visible scheduler statistics: current number of runnable
3019 * threads, current number of uninterruptible-sleeping threads, total
3020 * number of context switches performed since bootup.
3022 unsigned long nr_running(void)
3024 unsigned long i
, sum
= 0;
3026 for_each_online_cpu(i
)
3027 sum
+= cpu_rq(i
)->nr_running
;
3032 unsigned long nr_uninterruptible(void)
3034 unsigned long i
, sum
= 0;
3036 for_each_possible_cpu(i
)
3037 sum
+= cpu_rq(i
)->nr_uninterruptible
;
3040 * Since we read the counters lockless, it might be slightly
3041 * inaccurate. Do not allow it to go below zero though:
3043 if (unlikely((long)sum
< 0))
3049 unsigned long long nr_context_switches(void)
3052 unsigned long long sum
= 0;
3054 for_each_possible_cpu(i
)
3055 sum
+= cpu_rq(i
)->nr_switches
;
3060 unsigned long nr_iowait(void)
3062 unsigned long i
, sum
= 0;
3064 for_each_possible_cpu(i
)
3065 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
3070 unsigned long nr_iowait_cpu(int cpu
)
3072 struct rq
*this = cpu_rq(cpu
);
3073 return atomic_read(&this->nr_iowait
);
3076 unsigned long this_cpu_load(void)
3078 struct rq
*this = this_rq();
3079 return this->cpu_load
[0];
3083 /* Variables and functions for calc_load */
3084 static atomic_long_t calc_load_tasks
;
3085 static unsigned long calc_load_update
;
3086 unsigned long avenrun
[3];
3087 EXPORT_SYMBOL(avenrun
);
3089 static long calc_load_fold_active(struct rq
*this_rq
)
3091 long nr_active
, delta
= 0;
3093 nr_active
= this_rq
->nr_running
;
3094 nr_active
+= (long) this_rq
->nr_uninterruptible
;
3096 if (nr_active
!= this_rq
->calc_load_active
) {
3097 delta
= nr_active
- this_rq
->calc_load_active
;
3098 this_rq
->calc_load_active
= nr_active
;
3104 static unsigned long
3105 calc_load(unsigned long load
, unsigned long exp
, unsigned long active
)
3108 load
+= active
* (FIXED_1
- exp
);
3109 load
+= 1UL << (FSHIFT
- 1);
3110 return load
>> FSHIFT
;
3115 * For NO_HZ we delay the active fold to the next LOAD_FREQ update.
3117 * When making the ILB scale, we should try to pull this in as well.
3119 static atomic_long_t calc_load_tasks_idle
;
3121 static void calc_load_account_idle(struct rq
*this_rq
)
3125 delta
= calc_load_fold_active(this_rq
);
3127 atomic_long_add(delta
, &calc_load_tasks_idle
);
3130 static long calc_load_fold_idle(void)
3135 * Its got a race, we don't care...
3137 if (atomic_long_read(&calc_load_tasks_idle
))
3138 delta
= atomic_long_xchg(&calc_load_tasks_idle
, 0);
3144 * fixed_power_int - compute: x^n, in O(log n) time
3146 * @x: base of the power
3147 * @frac_bits: fractional bits of @x
3148 * @n: power to raise @x to.
3150 * By exploiting the relation between the definition of the natural power
3151 * function: x^n := x*x*...*x (x multiplied by itself for n times), and
3152 * the binary encoding of numbers used by computers: n := \Sum n_i * 2^i,
3153 * (where: n_i \elem {0, 1}, the binary vector representing n),
3154 * we find: x^n := x^(\Sum n_i * 2^i) := \Prod x^(n_i * 2^i), which is
3155 * of course trivially computable in O(log_2 n), the length of our binary
3158 static unsigned long
3159 fixed_power_int(unsigned long x
, unsigned int frac_bits
, unsigned int n
)
3161 unsigned long result
= 1UL << frac_bits
;
3166 result
+= 1UL << (frac_bits
- 1);
3167 result
>>= frac_bits
;
3173 x
+= 1UL << (frac_bits
- 1);
3181 * a1 = a0 * e + a * (1 - e)
3183 * a2 = a1 * e + a * (1 - e)
3184 * = (a0 * e + a * (1 - e)) * e + a * (1 - e)
3185 * = a0 * e^2 + a * (1 - e) * (1 + e)
3187 * a3 = a2 * e + a * (1 - e)
3188 * = (a0 * e^2 + a * (1 - e) * (1 + e)) * e + a * (1 - e)
3189 * = a0 * e^3 + a * (1 - e) * (1 + e + e^2)
3193 * an = a0 * e^n + a * (1 - e) * (1 + e + ... + e^n-1) [1]
3194 * = a0 * e^n + a * (1 - e) * (1 - e^n)/(1 - e)
3195 * = a0 * e^n + a * (1 - e^n)
3197 * [1] application of the geometric series:
3200 * S_n := \Sum x^i = -------------
3203 static unsigned long
3204 calc_load_n(unsigned long load
, unsigned long exp
,
3205 unsigned long active
, unsigned int n
)
3208 return calc_load(load
, fixed_power_int(exp
, FSHIFT
, n
), active
);
3212 * NO_HZ can leave us missing all per-cpu ticks calling
3213 * calc_load_account_active(), but since an idle CPU folds its delta into
3214 * calc_load_tasks_idle per calc_load_account_idle(), all we need to do is fold
3215 * in the pending idle delta if our idle period crossed a load cycle boundary.
3217 * Once we've updated the global active value, we need to apply the exponential
3218 * weights adjusted to the number of cycles missed.
3220 static void calc_global_nohz(unsigned long ticks
)
3222 long delta
, active
, n
;
3224 if (time_before(jiffies
, calc_load_update
))
3228 * If we crossed a calc_load_update boundary, make sure to fold
3229 * any pending idle changes, the respective CPUs might have
3230 * missed the tick driven calc_load_account_active() update
3233 delta
= calc_load_fold_idle();
3235 atomic_long_add(delta
, &calc_load_tasks
);
3238 * If we were idle for multiple load cycles, apply them.
3240 if (ticks
>= LOAD_FREQ
) {
3241 n
= ticks
/ LOAD_FREQ
;
3243 active
= atomic_long_read(&calc_load_tasks
);
3244 active
= active
> 0 ? active
* FIXED_1
: 0;
3246 avenrun
[0] = calc_load_n(avenrun
[0], EXP_1
, active
, n
);
3247 avenrun
[1] = calc_load_n(avenrun
[1], EXP_5
, active
, n
);
3248 avenrun
[2] = calc_load_n(avenrun
[2], EXP_15
, active
, n
);
3250 calc_load_update
+= n
* LOAD_FREQ
;
3254 * Its possible the remainder of the above division also crosses
3255 * a LOAD_FREQ period, the regular check in calc_global_load()
3256 * which comes after this will take care of that.
3258 * Consider us being 11 ticks before a cycle completion, and us
3259 * sleeping for 4*LOAD_FREQ + 22 ticks, then the above code will
3260 * age us 4 cycles, and the test in calc_global_load() will
3261 * pick up the final one.
3265 static void calc_load_account_idle(struct rq
*this_rq
)
3269 static inline long calc_load_fold_idle(void)
3274 static void calc_global_nohz(unsigned long ticks
)
3280 * get_avenrun - get the load average array
3281 * @loads: pointer to dest load array
3282 * @offset: offset to add
3283 * @shift: shift count to shift the result left
3285 * These values are estimates at best, so no need for locking.
3287 void get_avenrun(unsigned long *loads
, unsigned long offset
, int shift
)
3289 loads
[0] = (avenrun
[0] + offset
) << shift
;
3290 loads
[1] = (avenrun
[1] + offset
) << shift
;
3291 loads
[2] = (avenrun
[2] + offset
) << shift
;
3295 * calc_load - update the avenrun load estimates 10 ticks after the
3296 * CPUs have updated calc_load_tasks.
3298 void calc_global_load(unsigned long ticks
)
3302 calc_global_nohz(ticks
);
3304 if (time_before(jiffies
, calc_load_update
+ 10))
3307 active
= atomic_long_read(&calc_load_tasks
);
3308 active
= active
> 0 ? active
* FIXED_1
: 0;
3310 avenrun
[0] = calc_load(avenrun
[0], EXP_1
, active
);
3311 avenrun
[1] = calc_load(avenrun
[1], EXP_5
, active
);
3312 avenrun
[2] = calc_load(avenrun
[2], EXP_15
, active
);
3314 calc_load_update
+= LOAD_FREQ
;
3318 * Called from update_cpu_load() to periodically update this CPU's
3321 static void calc_load_account_active(struct rq
*this_rq
)
3325 if (time_before(jiffies
, this_rq
->calc_load_update
))
3328 delta
= calc_load_fold_active(this_rq
);
3329 delta
+= calc_load_fold_idle();
3331 atomic_long_add(delta
, &calc_load_tasks
);
3333 this_rq
->calc_load_update
+= LOAD_FREQ
;
3337 * The exact cpuload at various idx values, calculated at every tick would be
3338 * load = (2^idx - 1) / 2^idx * load + 1 / 2^idx * cur_load
3340 * If a cpu misses updates for n-1 ticks (as it was idle) and update gets called
3341 * on nth tick when cpu may be busy, then we have:
3342 * load = ((2^idx - 1) / 2^idx)^(n-1) * load
3343 * load = (2^idx - 1) / 2^idx) * load + 1 / 2^idx * cur_load
3345 * decay_load_missed() below does efficient calculation of
3346 * load = ((2^idx - 1) / 2^idx)^(n-1) * load
3347 * avoiding 0..n-1 loop doing load = ((2^idx - 1) / 2^idx) * load
3349 * The calculation is approximated on a 128 point scale.
3350 * degrade_zero_ticks is the number of ticks after which load at any
3351 * particular idx is approximated to be zero.
3352 * degrade_factor is a precomputed table, a row for each load idx.
3353 * Each column corresponds to degradation factor for a power of two ticks,
3354 * based on 128 point scale.
3356 * row 2, col 3 (=12) says that the degradation at load idx 2 after
3357 * 8 ticks is 12/128 (which is an approximation of exact factor 3^8/4^8).
3359 * With this power of 2 load factors, we can degrade the load n times
3360 * by looking at 1 bits in n and doing as many mult/shift instead of
3361 * n mult/shifts needed by the exact degradation.
3363 #define DEGRADE_SHIFT 7
3364 static const unsigned char
3365 degrade_zero_ticks
[CPU_LOAD_IDX_MAX
] = {0, 8, 32, 64, 128};
3366 static const unsigned char
3367 degrade_factor
[CPU_LOAD_IDX_MAX
][DEGRADE_SHIFT
+ 1] = {
3368 {0, 0, 0, 0, 0, 0, 0, 0},
3369 {64, 32, 8, 0, 0, 0, 0, 0},
3370 {96, 72, 40, 12, 1, 0, 0},
3371 {112, 98, 75, 43, 15, 1, 0},
3372 {120, 112, 98, 76, 45, 16, 2} };
3375 * Update cpu_load for any missed ticks, due to tickless idle. The backlog
3376 * would be when CPU is idle and so we just decay the old load without
3377 * adding any new load.
3379 static unsigned long
3380 decay_load_missed(unsigned long load
, unsigned long missed_updates
, int idx
)
3384 if (!missed_updates
)
3387 if (missed_updates
>= degrade_zero_ticks
[idx
])
3391 return load
>> missed_updates
;
3393 while (missed_updates
) {
3394 if (missed_updates
% 2)
3395 load
= (load
* degrade_factor
[idx
][j
]) >> DEGRADE_SHIFT
;
3397 missed_updates
>>= 1;
3404 * Update rq->cpu_load[] statistics. This function is usually called every
3405 * scheduler tick (TICK_NSEC). With tickless idle this will not be called
3406 * every tick. We fix it up based on jiffies.
3408 static void update_cpu_load(struct rq
*this_rq
)
3410 unsigned long this_load
= this_rq
->load
.weight
;
3411 unsigned long curr_jiffies
= jiffies
;
3412 unsigned long pending_updates
;
3415 this_rq
->nr_load_updates
++;
3417 /* Avoid repeated calls on same jiffy, when moving in and out of idle */
3418 if (curr_jiffies
== this_rq
->last_load_update_tick
)
3421 pending_updates
= curr_jiffies
- this_rq
->last_load_update_tick
;
3422 this_rq
->last_load_update_tick
= curr_jiffies
;
3424 /* Update our load: */
3425 this_rq
->cpu_load
[0] = this_load
; /* Fasttrack for idx 0 */
3426 for (i
= 1, scale
= 2; i
< CPU_LOAD_IDX_MAX
; i
++, scale
+= scale
) {
3427 unsigned long old_load
, new_load
;
3429 /* scale is effectively 1 << i now, and >> i divides by scale */
3431 old_load
= this_rq
->cpu_load
[i
];
3432 old_load
= decay_load_missed(old_load
, pending_updates
- 1, i
);
3433 new_load
= this_load
;
3435 * Round up the averaging division if load is increasing. This
3436 * prevents us from getting stuck on 9 if the load is 10, for
3439 if (new_load
> old_load
)
3440 new_load
+= scale
- 1;
3442 this_rq
->cpu_load
[i
] = (old_load
* (scale
- 1) + new_load
) >> i
;
3445 sched_avg_update(this_rq
);
3448 static void update_cpu_load_active(struct rq
*this_rq
)
3450 update_cpu_load(this_rq
);
3452 calc_load_account_active(this_rq
);
3458 * sched_exec - execve() is a valuable balancing opportunity, because at
3459 * this point the task has the smallest effective memory and cache footprint.
3461 void sched_exec(void)
3463 struct task_struct
*p
= current
;
3464 unsigned long flags
;
3468 rq
= task_rq_lock(p
, &flags
);
3469 dest_cpu
= p
->sched_class
->select_task_rq(rq
, p
, SD_BALANCE_EXEC
, 0);
3470 if (dest_cpu
== smp_processor_id())
3474 * select_task_rq() can race against ->cpus_allowed
3476 if (cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
) &&
3477 likely(cpu_active(dest_cpu
)) && migrate_task(p
, rq
)) {
3478 struct migration_arg arg
= { p
, dest_cpu
};
3480 task_rq_unlock(rq
, &flags
);
3481 stop_one_cpu(cpu_of(rq
), migration_cpu_stop
, &arg
);
3485 task_rq_unlock(rq
, &flags
);
3490 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
3492 EXPORT_PER_CPU_SYMBOL(kstat
);
3495 * Return any ns on the sched_clock that have not yet been accounted in
3496 * @p in case that task is currently running.
3498 * Called with task_rq_lock() held on @rq.
3500 static u64
do_task_delta_exec(struct task_struct
*p
, struct rq
*rq
)
3504 if (task_current(rq
, p
)) {
3505 update_rq_clock(rq
);
3506 ns
= rq
->clock_task
- p
->se
.exec_start
;
3514 unsigned long long task_delta_exec(struct task_struct
*p
)
3516 unsigned long flags
;
3520 rq
= task_rq_lock(p
, &flags
);
3521 ns
= do_task_delta_exec(p
, rq
);
3522 task_rq_unlock(rq
, &flags
);
3528 * Return accounted runtime for the task.
3529 * In case the task is currently running, return the runtime plus current's
3530 * pending runtime that have not been accounted yet.
3532 unsigned long long task_sched_runtime(struct task_struct
*p
)
3534 unsigned long flags
;
3538 rq
= task_rq_lock(p
, &flags
);
3539 ns
= p
->se
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
3540 task_rq_unlock(rq
, &flags
);
3546 * Return sum_exec_runtime for the thread group.
3547 * In case the task is currently running, return the sum plus current's
3548 * pending runtime that have not been accounted yet.
3550 * Note that the thread group might have other running tasks as well,
3551 * so the return value not includes other pending runtime that other
3552 * running tasks might have.
3554 unsigned long long thread_group_sched_runtime(struct task_struct
*p
)
3556 struct task_cputime totals
;
3557 unsigned long flags
;
3561 rq
= task_rq_lock(p
, &flags
);
3562 thread_group_cputime(p
, &totals
);
3563 ns
= totals
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
3564 task_rq_unlock(rq
, &flags
);
3570 * Account user cpu time to a process.
3571 * @p: the process that the cpu time gets accounted to
3572 * @cputime: the cpu time spent in user space since the last update
3573 * @cputime_scaled: cputime scaled by cpu frequency
3575 void account_user_time(struct task_struct
*p
, cputime_t cputime
,
3576 cputime_t cputime_scaled
)
3578 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3581 /* Add user time to process. */
3582 p
->utime
= cputime_add(p
->utime
, cputime
);
3583 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
3584 account_group_user_time(p
, cputime
);
3586 /* Add user time to cpustat. */
3587 tmp
= cputime_to_cputime64(cputime
);
3588 if (TASK_NICE(p
) > 0)
3589 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
3591 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
3593 cpuacct_update_stats(p
, CPUACCT_STAT_USER
, cputime
);
3594 /* Account for user time used */
3595 acct_update_integrals(p
);
3599 * Account guest cpu time to a process.
3600 * @p: the process that the cpu time gets accounted to
3601 * @cputime: the cpu time spent in virtual machine since the last update
3602 * @cputime_scaled: cputime scaled by cpu frequency
3604 static void account_guest_time(struct task_struct
*p
, cputime_t cputime
,
3605 cputime_t cputime_scaled
)
3608 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3610 tmp
= cputime_to_cputime64(cputime
);
3612 /* Add guest time to process. */
3613 p
->utime
= cputime_add(p
->utime
, cputime
);
3614 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
3615 account_group_user_time(p
, cputime
);
3616 p
->gtime
= cputime_add(p
->gtime
, cputime
);
3618 /* Add guest time to cpustat. */
3619 if (TASK_NICE(p
) > 0) {
3620 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
3621 cpustat
->guest_nice
= cputime64_add(cpustat
->guest_nice
, tmp
);
3623 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
3624 cpustat
->guest
= cputime64_add(cpustat
->guest
, tmp
);
3629 * Account system cpu time to a process and desired cpustat field
3630 * @p: the process that the cpu time gets accounted to
3631 * @cputime: the cpu time spent in kernel space since the last update
3632 * @cputime_scaled: cputime scaled by cpu frequency
3633 * @target_cputime64: pointer to cpustat field that has to be updated
3636 void __account_system_time(struct task_struct
*p
, cputime_t cputime
,
3637 cputime_t cputime_scaled
, cputime64_t
*target_cputime64
)
3639 cputime64_t tmp
= cputime_to_cputime64(cputime
);
3641 /* Add system time to process. */
3642 p
->stime
= cputime_add(p
->stime
, cputime
);
3643 p
->stimescaled
= cputime_add(p
->stimescaled
, cputime_scaled
);
3644 account_group_system_time(p
, cputime
);
3646 /* Add system time to cpustat. */
3647 *target_cputime64
= cputime64_add(*target_cputime64
, tmp
);
3648 cpuacct_update_stats(p
, CPUACCT_STAT_SYSTEM
, cputime
);
3650 /* Account for system time used */
3651 acct_update_integrals(p
);
3655 * Account system cpu time to a process.
3656 * @p: the process that the cpu time gets accounted to
3657 * @hardirq_offset: the offset to subtract from hardirq_count()
3658 * @cputime: the cpu time spent in kernel space since the last update
3659 * @cputime_scaled: cputime scaled by cpu frequency
3661 void account_system_time(struct task_struct
*p
, int hardirq_offset
,
3662 cputime_t cputime
, cputime_t cputime_scaled
)
3664 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3665 cputime64_t
*target_cputime64
;
3667 if ((p
->flags
& PF_VCPU
) && (irq_count() - hardirq_offset
== 0)) {
3668 account_guest_time(p
, cputime
, cputime_scaled
);
3672 if (hardirq_count() - hardirq_offset
)
3673 target_cputime64
= &cpustat
->irq
;
3674 else if (in_serving_softirq())
3675 target_cputime64
= &cpustat
->softirq
;
3677 target_cputime64
= &cpustat
->system
;
3679 __account_system_time(p
, cputime
, cputime_scaled
, target_cputime64
);
3683 * Account for involuntary wait time.
3684 * @cputime: the cpu time spent in involuntary wait
3686 void account_steal_time(cputime_t cputime
)
3688 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3689 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
3691 cpustat
->steal
= cputime64_add(cpustat
->steal
, cputime64
);
3695 * Account for idle time.
3696 * @cputime: the cpu time spent in idle wait
3698 void account_idle_time(cputime_t cputime
)
3700 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3701 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
3702 struct rq
*rq
= this_rq();
3704 if (atomic_read(&rq
->nr_iowait
) > 0)
3705 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, cputime64
);
3707 cpustat
->idle
= cputime64_add(cpustat
->idle
, cputime64
);
3710 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
3712 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
3714 * Account a tick to a process and cpustat
3715 * @p: the process that the cpu time gets accounted to
3716 * @user_tick: is the tick from userspace
3717 * @rq: the pointer to rq
3719 * Tick demultiplexing follows the order
3720 * - pending hardirq update
3721 * - pending softirq update
3725 * - check for guest_time
3726 * - else account as system_time
3728 * Check for hardirq is done both for system and user time as there is
3729 * no timer going off while we are on hardirq and hence we may never get an
3730 * opportunity to update it solely in system time.
3731 * p->stime and friends are only updated on system time and not on irq
3732 * softirq as those do not count in task exec_runtime any more.
3734 static void irqtime_account_process_tick(struct task_struct
*p
, int user_tick
,
3737 cputime_t one_jiffy_scaled
= cputime_to_scaled(cputime_one_jiffy
);
3738 cputime64_t tmp
= cputime_to_cputime64(cputime_one_jiffy
);
3739 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3741 if (irqtime_account_hi_update()) {
3742 cpustat
->irq
= cputime64_add(cpustat
->irq
, tmp
);
3743 } else if (irqtime_account_si_update()) {
3744 cpustat
->softirq
= cputime64_add(cpustat
->softirq
, tmp
);
3745 } else if (this_cpu_ksoftirqd() == p
) {
3747 * ksoftirqd time do not get accounted in cpu_softirq_time.
3748 * So, we have to handle it separately here.
3749 * Also, p->stime needs to be updated for ksoftirqd.
3751 __account_system_time(p
, cputime_one_jiffy
, one_jiffy_scaled
,
3753 } else if (user_tick
) {
3754 account_user_time(p
, cputime_one_jiffy
, one_jiffy_scaled
);
3755 } else if (p
== rq
->idle
) {
3756 account_idle_time(cputime_one_jiffy
);
3757 } else if (p
->flags
& PF_VCPU
) { /* System time or guest time */
3758 account_guest_time(p
, cputime_one_jiffy
, one_jiffy_scaled
);
3760 __account_system_time(p
, cputime_one_jiffy
, one_jiffy_scaled
,
3765 static void irqtime_account_idle_ticks(int ticks
)
3768 struct rq
*rq
= this_rq();
3770 for (i
= 0; i
< ticks
; i
++)
3771 irqtime_account_process_tick(current
, 0, rq
);
3773 #else /* CONFIG_IRQ_TIME_ACCOUNTING */
3774 static void irqtime_account_idle_ticks(int ticks
) {}
3775 static void irqtime_account_process_tick(struct task_struct
*p
, int user_tick
,
3777 #endif /* CONFIG_IRQ_TIME_ACCOUNTING */
3780 * Account a single tick of cpu time.
3781 * @p: the process that the cpu time gets accounted to
3782 * @user_tick: indicates if the tick is a user or a system tick
3784 void account_process_tick(struct task_struct
*p
, int user_tick
)
3786 cputime_t one_jiffy_scaled
= cputime_to_scaled(cputime_one_jiffy
);
3787 struct rq
*rq
= this_rq();
3789 if (sched_clock_irqtime
) {
3790 irqtime_account_process_tick(p
, user_tick
, rq
);
3795 account_user_time(p
, cputime_one_jiffy
, one_jiffy_scaled
);
3796 else if ((p
!= rq
->idle
) || (irq_count() != HARDIRQ_OFFSET
))
3797 account_system_time(p
, HARDIRQ_OFFSET
, cputime_one_jiffy
,
3800 account_idle_time(cputime_one_jiffy
);
3804 * Account multiple ticks of steal time.
3805 * @p: the process from which the cpu time has been stolen
3806 * @ticks: number of stolen ticks
3808 void account_steal_ticks(unsigned long ticks
)
3810 account_steal_time(jiffies_to_cputime(ticks
));
3814 * Account multiple ticks of idle time.
3815 * @ticks: number of stolen ticks
3817 void account_idle_ticks(unsigned long ticks
)
3820 if (sched_clock_irqtime
) {
3821 irqtime_account_idle_ticks(ticks
);
3825 account_idle_time(jiffies_to_cputime(ticks
));
3831 * Use precise platform statistics if available:
3833 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
3834 void task_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
3840 void thread_group_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
3842 struct task_cputime cputime
;
3844 thread_group_cputime(p
, &cputime
);
3846 *ut
= cputime
.utime
;
3847 *st
= cputime
.stime
;
3851 #ifndef nsecs_to_cputime
3852 # define nsecs_to_cputime(__nsecs) nsecs_to_jiffies(__nsecs)
3855 void task_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
3857 cputime_t rtime
, utime
= p
->utime
, total
= cputime_add(utime
, p
->stime
);
3860 * Use CFS's precise accounting:
3862 rtime
= nsecs_to_cputime(p
->se
.sum_exec_runtime
);
3868 do_div(temp
, total
);
3869 utime
= (cputime_t
)temp
;
3874 * Compare with previous values, to keep monotonicity:
3876 p
->prev_utime
= max(p
->prev_utime
, utime
);
3877 p
->prev_stime
= max(p
->prev_stime
, cputime_sub(rtime
, p
->prev_utime
));
3879 *ut
= p
->prev_utime
;
3880 *st
= p
->prev_stime
;
3884 * Must be called with siglock held.
3886 void thread_group_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
3888 struct signal_struct
*sig
= p
->signal
;
3889 struct task_cputime cputime
;
3890 cputime_t rtime
, utime
, total
;
3892 thread_group_cputime(p
, &cputime
);
3894 total
= cputime_add(cputime
.utime
, cputime
.stime
);
3895 rtime
= nsecs_to_cputime(cputime
.sum_exec_runtime
);
3900 temp
*= cputime
.utime
;
3901 do_div(temp
, total
);
3902 utime
= (cputime_t
)temp
;
3906 sig
->prev_utime
= max(sig
->prev_utime
, utime
);
3907 sig
->prev_stime
= max(sig
->prev_stime
,
3908 cputime_sub(rtime
, sig
->prev_utime
));
3910 *ut
= sig
->prev_utime
;
3911 *st
= sig
->prev_stime
;
3916 * This function gets called by the timer code, with HZ frequency.
3917 * We call it with interrupts disabled.
3919 * It also gets called by the fork code, when changing the parent's
3922 void scheduler_tick(void)
3924 int cpu
= smp_processor_id();
3925 struct rq
*rq
= cpu_rq(cpu
);
3926 struct task_struct
*curr
= rq
->curr
;
3930 raw_spin_lock(&rq
->lock
);
3931 update_rq_clock(rq
);
3932 update_cpu_load_active(rq
);
3933 curr
->sched_class
->task_tick(rq
, curr
, 0);
3934 raw_spin_unlock(&rq
->lock
);
3936 perf_event_task_tick();
3939 rq
->idle_at_tick
= idle_cpu(cpu
);
3940 trigger_load_balance(rq
, cpu
);
3944 notrace
unsigned long get_parent_ip(unsigned long addr
)
3946 if (in_lock_functions(addr
)) {
3947 addr
= CALLER_ADDR2
;
3948 if (in_lock_functions(addr
))
3949 addr
= CALLER_ADDR3
;
3954 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
3955 defined(CONFIG_PREEMPT_TRACER))
3957 void __kprobes
add_preempt_count(int val
)
3959 #ifdef CONFIG_DEBUG_PREEMPT
3963 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
3966 preempt_count() += val
;
3967 #ifdef CONFIG_DEBUG_PREEMPT
3969 * Spinlock count overflowing soon?
3971 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
3974 if (preempt_count() == val
)
3975 trace_preempt_off(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
3977 EXPORT_SYMBOL(add_preempt_count
);
3979 void __kprobes
sub_preempt_count(int val
)
3981 #ifdef CONFIG_DEBUG_PREEMPT
3985 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
3988 * Is the spinlock portion underflowing?
3990 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
3991 !(preempt_count() & PREEMPT_MASK
)))
3995 if (preempt_count() == val
)
3996 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
3997 preempt_count() -= val
;
3999 EXPORT_SYMBOL(sub_preempt_count
);
4004 * Print scheduling while atomic bug:
4006 static noinline
void __schedule_bug(struct task_struct
*prev
)
4008 struct pt_regs
*regs
= get_irq_regs();
4010 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
4011 prev
->comm
, prev
->pid
, preempt_count());
4013 debug_show_held_locks(prev
);
4015 if (irqs_disabled())
4016 print_irqtrace_events(prev
);
4025 * Various schedule()-time debugging checks and statistics:
4027 static inline void schedule_debug(struct task_struct
*prev
)
4030 * Test if we are atomic. Since do_exit() needs to call into
4031 * schedule() atomically, we ignore that path for now.
4032 * Otherwise, whine if we are scheduling when we should not be.
4034 if (unlikely(in_atomic_preempt_off() && !prev
->exit_state
))
4035 __schedule_bug(prev
);
4037 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
4039 schedstat_inc(this_rq(), sched_count
);
4040 #ifdef CONFIG_SCHEDSTATS
4041 if (unlikely(prev
->lock_depth
>= 0)) {
4042 schedstat_inc(this_rq(), rq_sched_info
.bkl_count
);
4043 schedstat_inc(prev
, sched_info
.bkl_count
);
4048 static void put_prev_task(struct rq
*rq
, struct task_struct
*prev
)
4051 update_rq_clock(rq
);
4052 prev
->sched_class
->put_prev_task(rq
, prev
);
4056 * Pick up the highest-prio task:
4058 static inline struct task_struct
*
4059 pick_next_task(struct rq
*rq
)
4061 const struct sched_class
*class;
4062 struct task_struct
*p
;
4065 * Optimization: we know that if all tasks are in
4066 * the fair class we can call that function directly:
4068 if (likely(rq
->nr_running
== rq
->cfs
.nr_running
)) {
4069 p
= fair_sched_class
.pick_next_task(rq
);
4074 for_each_class(class) {
4075 p
= class->pick_next_task(rq
);
4080 BUG(); /* the idle class will always have a runnable task */
4084 * schedule() is the main scheduler function.
4086 asmlinkage
void __sched
schedule(void)
4088 struct task_struct
*prev
, *next
;
4089 unsigned long *switch_count
;
4095 cpu
= smp_processor_id();
4097 rcu_note_context_switch(cpu
);
4100 schedule_debug(prev
);
4102 if (sched_feat(HRTICK
))
4105 raw_spin_lock_irq(&rq
->lock
);
4107 switch_count
= &prev
->nivcsw
;
4108 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
4109 if (unlikely(signal_pending_state(prev
->state
, prev
))) {
4110 prev
->state
= TASK_RUNNING
;
4113 * If a worker is going to sleep, notify and
4114 * ask workqueue whether it wants to wake up a
4115 * task to maintain concurrency. If so, wake
4118 if (prev
->flags
& PF_WQ_WORKER
) {
4119 struct task_struct
*to_wakeup
;
4121 to_wakeup
= wq_worker_sleeping(prev
, cpu
);
4123 try_to_wake_up_local(to_wakeup
);
4125 deactivate_task(rq
, prev
, DEQUEUE_SLEEP
);
4128 * If we are going to sleep and we have plugged IO queued, make
4129 * sure to submit it to avoid deadlocks.
4131 if (blk_needs_flush_plug(prev
)) {
4132 raw_spin_unlock(&rq
->lock
);
4133 blk_flush_plug(prev
);
4134 raw_spin_lock(&rq
->lock
);
4137 switch_count
= &prev
->nvcsw
;
4140 pre_schedule(rq
, prev
);
4142 if (unlikely(!rq
->nr_running
))
4143 idle_balance(cpu
, rq
);
4145 put_prev_task(rq
, prev
);
4146 next
= pick_next_task(rq
);
4147 clear_tsk_need_resched(prev
);
4148 rq
->skip_clock_update
= 0;
4150 if (likely(prev
!= next
)) {
4155 context_switch(rq
, prev
, next
); /* unlocks the rq */
4157 * The context switch have flipped the stack from under us
4158 * and restored the local variables which were saved when
4159 * this task called schedule() in the past. prev == current
4160 * is still correct, but it can be moved to another cpu/rq.
4162 cpu
= smp_processor_id();
4165 raw_spin_unlock_irq(&rq
->lock
);
4169 preempt_enable_no_resched();
4173 EXPORT_SYMBOL(schedule
);
4175 #ifdef CONFIG_MUTEX_SPIN_ON_OWNER
4177 static inline bool owner_running(struct mutex
*lock
, struct task_struct
*owner
)
4182 if (lock
->owner
!= owner
)
4186 * Ensure we emit the owner->on_cpu, dereference _after_ checking
4187 * lock->owner still matches owner, if that fails, owner might
4188 * point to free()d memory, if it still matches, the rcu_read_lock()
4189 * ensures the memory stays valid.
4193 ret
= owner
->on_cpu
;
4201 * Look out! "owner" is an entirely speculative pointer
4202 * access and not reliable.
4204 int mutex_spin_on_owner(struct mutex
*lock
, struct task_struct
*owner
)
4206 if (!sched_feat(OWNER_SPIN
))
4209 while (owner_running(lock
, owner
)) {
4213 arch_mutex_cpu_relax();
4217 * If the owner changed to another task there is likely
4218 * heavy contention, stop spinning.
4227 #ifdef CONFIG_PREEMPT
4229 * this is the entry point to schedule() from in-kernel preemption
4230 * off of preempt_enable. Kernel preemptions off return from interrupt
4231 * occur there and call schedule directly.
4233 asmlinkage
void __sched notrace
preempt_schedule(void)
4235 struct thread_info
*ti
= current_thread_info();
4238 * If there is a non-zero preempt_count or interrupts are disabled,
4239 * we do not want to preempt the current task. Just return..
4241 if (likely(ti
->preempt_count
|| irqs_disabled()))
4245 add_preempt_count_notrace(PREEMPT_ACTIVE
);
4247 sub_preempt_count_notrace(PREEMPT_ACTIVE
);
4250 * Check again in case we missed a preemption opportunity
4251 * between schedule and now.
4254 } while (need_resched());
4256 EXPORT_SYMBOL(preempt_schedule
);
4259 * this is the entry point to schedule() from kernel preemption
4260 * off of irq context.
4261 * Note, that this is called and return with irqs disabled. This will
4262 * protect us against recursive calling from irq.
4264 asmlinkage
void __sched
preempt_schedule_irq(void)
4266 struct thread_info
*ti
= current_thread_info();
4268 /* Catch callers which need to be fixed */
4269 BUG_ON(ti
->preempt_count
|| !irqs_disabled());
4272 add_preempt_count(PREEMPT_ACTIVE
);
4275 local_irq_disable();
4276 sub_preempt_count(PREEMPT_ACTIVE
);
4279 * Check again in case we missed a preemption opportunity
4280 * between schedule and now.
4283 } while (need_resched());
4286 #endif /* CONFIG_PREEMPT */
4288 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int wake_flags
,
4291 return try_to_wake_up(curr
->private, mode
, wake_flags
);
4293 EXPORT_SYMBOL(default_wake_function
);
4296 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
4297 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
4298 * number) then we wake all the non-exclusive tasks and one exclusive task.
4300 * There are circumstances in which we can try to wake a task which has already
4301 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
4302 * zero in this (rare) case, and we handle it by continuing to scan the queue.
4304 static void __wake_up_common(wait_queue_head_t
*q
, unsigned int mode
,
4305 int nr_exclusive
, int wake_flags
, void *key
)
4307 wait_queue_t
*curr
, *next
;
4309 list_for_each_entry_safe(curr
, next
, &q
->task_list
, task_list
) {
4310 unsigned flags
= curr
->flags
;
4312 if (curr
->func(curr
, mode
, wake_flags
, key
) &&
4313 (flags
& WQ_FLAG_EXCLUSIVE
) && !--nr_exclusive
)
4319 * __wake_up - wake up threads blocked on a waitqueue.
4321 * @mode: which threads
4322 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4323 * @key: is directly passed to the wakeup function
4325 * It may be assumed that this function implies a write memory barrier before
4326 * changing the task state if and only if any tasks are woken up.
4328 void __wake_up(wait_queue_head_t
*q
, unsigned int mode
,
4329 int nr_exclusive
, void *key
)
4331 unsigned long flags
;
4333 spin_lock_irqsave(&q
->lock
, flags
);
4334 __wake_up_common(q
, mode
, nr_exclusive
, 0, key
);
4335 spin_unlock_irqrestore(&q
->lock
, flags
);
4337 EXPORT_SYMBOL(__wake_up
);
4340 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
4342 void __wake_up_locked(wait_queue_head_t
*q
, unsigned int mode
)
4344 __wake_up_common(q
, mode
, 1, 0, NULL
);
4346 EXPORT_SYMBOL_GPL(__wake_up_locked
);
4348 void __wake_up_locked_key(wait_queue_head_t
*q
, unsigned int mode
, void *key
)
4350 __wake_up_common(q
, mode
, 1, 0, key
);
4352 EXPORT_SYMBOL_GPL(__wake_up_locked_key
);
4355 * __wake_up_sync_key - wake up threads blocked on a waitqueue.
4357 * @mode: which threads
4358 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4359 * @key: opaque value to be passed to wakeup targets
4361 * The sync wakeup differs that the waker knows that it will schedule
4362 * away soon, so while the target thread will be woken up, it will not
4363 * be migrated to another CPU - ie. the two threads are 'synchronized'
4364 * with each other. This can prevent needless bouncing between CPUs.
4366 * On UP it can prevent extra preemption.
4368 * It may be assumed that this function implies a write memory barrier before
4369 * changing the task state if and only if any tasks are woken up.
4371 void __wake_up_sync_key(wait_queue_head_t
*q
, unsigned int mode
,
4372 int nr_exclusive
, void *key
)
4374 unsigned long flags
;
4375 int wake_flags
= WF_SYNC
;
4380 if (unlikely(!nr_exclusive
))
4383 spin_lock_irqsave(&q
->lock
, flags
);
4384 __wake_up_common(q
, mode
, nr_exclusive
, wake_flags
, key
);
4385 spin_unlock_irqrestore(&q
->lock
, flags
);
4387 EXPORT_SYMBOL_GPL(__wake_up_sync_key
);
4390 * __wake_up_sync - see __wake_up_sync_key()
4392 void __wake_up_sync(wait_queue_head_t
*q
, unsigned int mode
, int nr_exclusive
)
4394 __wake_up_sync_key(q
, mode
, nr_exclusive
, NULL
);
4396 EXPORT_SYMBOL_GPL(__wake_up_sync
); /* For internal use only */
4399 * complete: - signals a single thread waiting on this completion
4400 * @x: holds the state of this particular completion
4402 * This will wake up a single thread waiting on this completion. Threads will be
4403 * awakened in the same order in which they were queued.
4405 * See also complete_all(), wait_for_completion() and related routines.
4407 * It may be assumed that this function implies a write memory barrier before
4408 * changing the task state if and only if any tasks are woken up.
4410 void complete(struct completion
*x
)
4412 unsigned long flags
;
4414 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4416 __wake_up_common(&x
->wait
, TASK_NORMAL
, 1, 0, NULL
);
4417 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4419 EXPORT_SYMBOL(complete
);
4422 * complete_all: - signals all threads waiting on this completion
4423 * @x: holds the state of this particular completion
4425 * This will wake up all threads waiting on this particular completion event.
4427 * It may be assumed that this function implies a write memory barrier before
4428 * changing the task state if and only if any tasks are woken up.
4430 void complete_all(struct completion
*x
)
4432 unsigned long flags
;
4434 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4435 x
->done
+= UINT_MAX
/2;
4436 __wake_up_common(&x
->wait
, TASK_NORMAL
, 0, 0, NULL
);
4437 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4439 EXPORT_SYMBOL(complete_all
);
4441 static inline long __sched
4442 do_wait_for_common(struct completion
*x
, long timeout
, int state
)
4445 DECLARE_WAITQUEUE(wait
, current
);
4447 __add_wait_queue_tail_exclusive(&x
->wait
, &wait
);
4449 if (signal_pending_state(state
, current
)) {
4450 timeout
= -ERESTARTSYS
;
4453 __set_current_state(state
);
4454 spin_unlock_irq(&x
->wait
.lock
);
4455 timeout
= schedule_timeout(timeout
);
4456 spin_lock_irq(&x
->wait
.lock
);
4457 } while (!x
->done
&& timeout
);
4458 __remove_wait_queue(&x
->wait
, &wait
);
4463 return timeout
?: 1;
4467 wait_for_common(struct completion
*x
, long timeout
, int state
)
4471 spin_lock_irq(&x
->wait
.lock
);
4472 timeout
= do_wait_for_common(x
, timeout
, state
);
4473 spin_unlock_irq(&x
->wait
.lock
);
4478 * wait_for_completion: - waits for completion of a task
4479 * @x: holds the state of this particular completion
4481 * This waits to be signaled for completion of a specific task. It is NOT
4482 * interruptible and there is no timeout.
4484 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
4485 * and interrupt capability. Also see complete().
4487 void __sched
wait_for_completion(struct completion
*x
)
4489 wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
4491 EXPORT_SYMBOL(wait_for_completion
);
4494 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
4495 * @x: holds the state of this particular completion
4496 * @timeout: timeout value in jiffies
4498 * This waits for either a completion of a specific task to be signaled or for a
4499 * specified timeout to expire. The timeout is in jiffies. It is not
4502 unsigned long __sched
4503 wait_for_completion_timeout(struct completion
*x
, unsigned long timeout
)
4505 return wait_for_common(x
, timeout
, TASK_UNINTERRUPTIBLE
);
4507 EXPORT_SYMBOL(wait_for_completion_timeout
);
4510 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
4511 * @x: holds the state of this particular completion
4513 * This waits for completion of a specific task to be signaled. It is
4516 int __sched
wait_for_completion_interruptible(struct completion
*x
)
4518 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_INTERRUPTIBLE
);
4519 if (t
== -ERESTARTSYS
)
4523 EXPORT_SYMBOL(wait_for_completion_interruptible
);
4526 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
4527 * @x: holds the state of this particular completion
4528 * @timeout: timeout value in jiffies
4530 * This waits for either a completion of a specific task to be signaled or for a
4531 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
4534 wait_for_completion_interruptible_timeout(struct completion
*x
,
4535 unsigned long timeout
)
4537 return wait_for_common(x
, timeout
, TASK_INTERRUPTIBLE
);
4539 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout
);
4542 * wait_for_completion_killable: - waits for completion of a task (killable)
4543 * @x: holds the state of this particular completion
4545 * This waits to be signaled for completion of a specific task. It can be
4546 * interrupted by a kill signal.
4548 int __sched
wait_for_completion_killable(struct completion
*x
)
4550 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_KILLABLE
);
4551 if (t
== -ERESTARTSYS
)
4555 EXPORT_SYMBOL(wait_for_completion_killable
);
4558 * wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable))
4559 * @x: holds the state of this particular completion
4560 * @timeout: timeout value in jiffies
4562 * This waits for either a completion of a specific task to be
4563 * signaled or for a specified timeout to expire. It can be
4564 * interrupted by a kill signal. The timeout is in jiffies.
4567 wait_for_completion_killable_timeout(struct completion
*x
,
4568 unsigned long timeout
)
4570 return wait_for_common(x
, timeout
, TASK_KILLABLE
);
4572 EXPORT_SYMBOL(wait_for_completion_killable_timeout
);
4575 * try_wait_for_completion - try to decrement a completion without blocking
4576 * @x: completion structure
4578 * Returns: 0 if a decrement cannot be done without blocking
4579 * 1 if a decrement succeeded.
4581 * If a completion is being used as a counting completion,
4582 * attempt to decrement the counter without blocking. This
4583 * enables us to avoid waiting if the resource the completion
4584 * is protecting is not available.
4586 bool try_wait_for_completion(struct completion
*x
)
4588 unsigned long flags
;
4591 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4596 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4599 EXPORT_SYMBOL(try_wait_for_completion
);
4602 * completion_done - Test to see if a completion has any waiters
4603 * @x: completion structure
4605 * Returns: 0 if there are waiters (wait_for_completion() in progress)
4606 * 1 if there are no waiters.
4609 bool completion_done(struct completion
*x
)
4611 unsigned long flags
;
4614 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4617 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4620 EXPORT_SYMBOL(completion_done
);
4623 sleep_on_common(wait_queue_head_t
*q
, int state
, long timeout
)
4625 unsigned long flags
;
4628 init_waitqueue_entry(&wait
, current
);
4630 __set_current_state(state
);
4632 spin_lock_irqsave(&q
->lock
, flags
);
4633 __add_wait_queue(q
, &wait
);
4634 spin_unlock(&q
->lock
);
4635 timeout
= schedule_timeout(timeout
);
4636 spin_lock_irq(&q
->lock
);
4637 __remove_wait_queue(q
, &wait
);
4638 spin_unlock_irqrestore(&q
->lock
, flags
);
4643 void __sched
interruptible_sleep_on(wait_queue_head_t
*q
)
4645 sleep_on_common(q
, TASK_INTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
4647 EXPORT_SYMBOL(interruptible_sleep_on
);
4650 interruptible_sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
4652 return sleep_on_common(q
, TASK_INTERRUPTIBLE
, timeout
);
4654 EXPORT_SYMBOL(interruptible_sleep_on_timeout
);
4656 void __sched
sleep_on(wait_queue_head_t
*q
)
4658 sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
4660 EXPORT_SYMBOL(sleep_on
);
4662 long __sched
sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
4664 return sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, timeout
);
4666 EXPORT_SYMBOL(sleep_on_timeout
);
4668 #ifdef CONFIG_RT_MUTEXES
4671 * rt_mutex_setprio - set the current priority of a task
4673 * @prio: prio value (kernel-internal form)
4675 * This function changes the 'effective' priority of a task. It does
4676 * not touch ->normal_prio like __setscheduler().
4678 * Used by the rt_mutex code to implement priority inheritance logic.
4680 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
4682 unsigned long flags
;
4683 int oldprio
, on_rq
, running
;
4685 const struct sched_class
*prev_class
;
4687 BUG_ON(prio
< 0 || prio
> MAX_PRIO
);
4689 rq
= task_rq_lock(p
, &flags
);
4691 trace_sched_pi_setprio(p
, prio
);
4693 prev_class
= p
->sched_class
;
4694 on_rq
= p
->se
.on_rq
;
4695 running
= task_current(rq
, p
);
4697 dequeue_task(rq
, p
, 0);
4699 p
->sched_class
->put_prev_task(rq
, p
);
4702 p
->sched_class
= &rt_sched_class
;
4704 p
->sched_class
= &fair_sched_class
;
4709 p
->sched_class
->set_curr_task(rq
);
4711 enqueue_task(rq
, p
, oldprio
< prio
? ENQUEUE_HEAD
: 0);
4713 check_class_changed(rq
, p
, prev_class
, oldprio
);
4714 task_rq_unlock(rq
, &flags
);
4719 void set_user_nice(struct task_struct
*p
, long nice
)
4721 int old_prio
, delta
, on_rq
;
4722 unsigned long flags
;
4725 if (TASK_NICE(p
) == nice
|| nice
< -20 || nice
> 19)
4728 * We have to be careful, if called from sys_setpriority(),
4729 * the task might be in the middle of scheduling on another CPU.
4731 rq
= task_rq_lock(p
, &flags
);
4733 * The RT priorities are set via sched_setscheduler(), but we still
4734 * allow the 'normal' nice value to be set - but as expected
4735 * it wont have any effect on scheduling until the task is
4736 * SCHED_FIFO/SCHED_RR:
4738 if (task_has_rt_policy(p
)) {
4739 p
->static_prio
= NICE_TO_PRIO(nice
);
4742 on_rq
= p
->se
.on_rq
;
4744 dequeue_task(rq
, p
, 0);
4746 p
->static_prio
= NICE_TO_PRIO(nice
);
4749 p
->prio
= effective_prio(p
);
4750 delta
= p
->prio
- old_prio
;
4753 enqueue_task(rq
, p
, 0);
4755 * If the task increased its priority or is running and
4756 * lowered its priority, then reschedule its CPU:
4758 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
4759 resched_task(rq
->curr
);
4762 task_rq_unlock(rq
, &flags
);
4764 EXPORT_SYMBOL(set_user_nice
);
4767 * can_nice - check if a task can reduce its nice value
4771 int can_nice(const struct task_struct
*p
, const int nice
)
4773 /* convert nice value [19,-20] to rlimit style value [1,40] */
4774 int nice_rlim
= 20 - nice
;
4776 return (nice_rlim
<= task_rlimit(p
, RLIMIT_NICE
) ||
4777 capable(CAP_SYS_NICE
));
4780 #ifdef __ARCH_WANT_SYS_NICE
4783 * sys_nice - change the priority of the current process.
4784 * @increment: priority increment
4786 * sys_setpriority is a more generic, but much slower function that
4787 * does similar things.
4789 SYSCALL_DEFINE1(nice
, int, increment
)
4794 * Setpriority might change our priority at the same moment.
4795 * We don't have to worry. Conceptually one call occurs first
4796 * and we have a single winner.
4798 if (increment
< -40)
4803 nice
= TASK_NICE(current
) + increment
;
4809 if (increment
< 0 && !can_nice(current
, nice
))
4812 retval
= security_task_setnice(current
, nice
);
4816 set_user_nice(current
, nice
);
4823 * task_prio - return the priority value of a given task.
4824 * @p: the task in question.
4826 * This is the priority value as seen by users in /proc.
4827 * RT tasks are offset by -200. Normal tasks are centered
4828 * around 0, value goes from -16 to +15.
4830 int task_prio(const struct task_struct
*p
)
4832 return p
->prio
- MAX_RT_PRIO
;
4836 * task_nice - return the nice value of a given task.
4837 * @p: the task in question.
4839 int task_nice(const struct task_struct
*p
)
4841 return TASK_NICE(p
);
4843 EXPORT_SYMBOL(task_nice
);
4846 * idle_cpu - is a given cpu idle currently?
4847 * @cpu: the processor in question.
4849 int idle_cpu(int cpu
)
4851 return cpu_curr(cpu
) == cpu_rq(cpu
)->idle
;
4855 * idle_task - return the idle task for a given cpu.
4856 * @cpu: the processor in question.
4858 struct task_struct
*idle_task(int cpu
)
4860 return cpu_rq(cpu
)->idle
;
4864 * find_process_by_pid - find a process with a matching PID value.
4865 * @pid: the pid in question.
4867 static struct task_struct
*find_process_by_pid(pid_t pid
)
4869 return pid
? find_task_by_vpid(pid
) : current
;
4872 /* Actually do priority change: must hold rq lock. */
4874 __setscheduler(struct rq
*rq
, struct task_struct
*p
, int policy
, int prio
)
4876 BUG_ON(p
->se
.on_rq
);
4879 p
->rt_priority
= prio
;
4880 p
->normal_prio
= normal_prio(p
);
4881 /* we are holding p->pi_lock already */
4882 p
->prio
= rt_mutex_getprio(p
);
4883 if (rt_prio(p
->prio
))
4884 p
->sched_class
= &rt_sched_class
;
4886 p
->sched_class
= &fair_sched_class
;
4891 * check the target process has a UID that matches the current process's
4893 static bool check_same_owner(struct task_struct
*p
)
4895 const struct cred
*cred
= current_cred(), *pcred
;
4899 pcred
= __task_cred(p
);
4900 if (cred
->user
->user_ns
== pcred
->user
->user_ns
)
4901 match
= (cred
->euid
== pcred
->euid
||
4902 cred
->euid
== pcred
->uid
);
4909 static int __sched_setscheduler(struct task_struct
*p
, int policy
,
4910 const struct sched_param
*param
, bool user
)
4912 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
4913 unsigned long flags
;
4914 const struct sched_class
*prev_class
;
4918 /* may grab non-irq protected spin_locks */
4919 BUG_ON(in_interrupt());
4921 /* double check policy once rq lock held */
4923 reset_on_fork
= p
->sched_reset_on_fork
;
4924 policy
= oldpolicy
= p
->policy
;
4926 reset_on_fork
= !!(policy
& SCHED_RESET_ON_FORK
);
4927 policy
&= ~SCHED_RESET_ON_FORK
;
4929 if (policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
4930 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
4931 policy
!= SCHED_IDLE
)
4936 * Valid priorities for SCHED_FIFO and SCHED_RR are
4937 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
4938 * SCHED_BATCH and SCHED_IDLE is 0.
4940 if (param
->sched_priority
< 0 ||
4941 (p
->mm
&& param
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
4942 (!p
->mm
&& param
->sched_priority
> MAX_RT_PRIO
-1))
4944 if (rt_policy(policy
) != (param
->sched_priority
!= 0))
4948 * Allow unprivileged RT tasks to decrease priority:
4950 if (user
&& !capable(CAP_SYS_NICE
)) {
4951 if (rt_policy(policy
)) {
4952 unsigned long rlim_rtprio
=
4953 task_rlimit(p
, RLIMIT_RTPRIO
);
4955 /* can't set/change the rt policy */
4956 if (policy
!= p
->policy
&& !rlim_rtprio
)
4959 /* can't increase priority */
4960 if (param
->sched_priority
> p
->rt_priority
&&
4961 param
->sched_priority
> rlim_rtprio
)
4966 * Treat SCHED_IDLE as nice 20. Only allow a switch to
4967 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
4969 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
) {
4970 if (!can_nice(p
, TASK_NICE(p
)))
4974 /* can't change other user's priorities */
4975 if (!check_same_owner(p
))
4978 /* Normal users shall not reset the sched_reset_on_fork flag */
4979 if (p
->sched_reset_on_fork
&& !reset_on_fork
)
4984 retval
= security_task_setscheduler(p
);
4990 * make sure no PI-waiters arrive (or leave) while we are
4991 * changing the priority of the task:
4993 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
4995 * To be able to change p->policy safely, the appropriate
4996 * runqueue lock must be held.
4998 rq
= __task_rq_lock(p
);
5001 * Changing the policy of the stop threads its a very bad idea
5003 if (p
== rq
->stop
) {
5004 __task_rq_unlock(rq
);
5005 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
5010 * If not changing anything there's no need to proceed further:
5012 if (unlikely(policy
== p
->policy
&& (!rt_policy(policy
) ||
5013 param
->sched_priority
== p
->rt_priority
))) {
5015 __task_rq_unlock(rq
);
5016 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
5020 #ifdef CONFIG_RT_GROUP_SCHED
5023 * Do not allow realtime tasks into groups that have no runtime
5026 if (rt_bandwidth_enabled() && rt_policy(policy
) &&
5027 task_group(p
)->rt_bandwidth
.rt_runtime
== 0 &&
5028 !task_group_is_autogroup(task_group(p
))) {
5029 __task_rq_unlock(rq
);
5030 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
5036 /* recheck policy now with rq lock held */
5037 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
5038 policy
= oldpolicy
= -1;
5039 __task_rq_unlock(rq
);
5040 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
5043 on_rq
= p
->se
.on_rq
;
5044 running
= task_current(rq
, p
);
5046 deactivate_task(rq
, p
, 0);
5048 p
->sched_class
->put_prev_task(rq
, p
);
5050 p
->sched_reset_on_fork
= reset_on_fork
;
5053 prev_class
= p
->sched_class
;
5054 __setscheduler(rq
, p
, policy
, param
->sched_priority
);
5057 p
->sched_class
->set_curr_task(rq
);
5059 activate_task(rq
, p
, 0);
5061 check_class_changed(rq
, p
, prev_class
, oldprio
);
5062 __task_rq_unlock(rq
);
5063 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
5065 rt_mutex_adjust_pi(p
);
5071 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
5072 * @p: the task in question.
5073 * @policy: new policy.
5074 * @param: structure containing the new RT priority.
5076 * NOTE that the task may be already dead.
5078 int sched_setscheduler(struct task_struct
*p
, int policy
,
5079 const struct sched_param
*param
)
5081 return __sched_setscheduler(p
, policy
, param
, true);
5083 EXPORT_SYMBOL_GPL(sched_setscheduler
);
5086 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
5087 * @p: the task in question.
5088 * @policy: new policy.
5089 * @param: structure containing the new RT priority.
5091 * Just like sched_setscheduler, only don't bother checking if the
5092 * current context has permission. For example, this is needed in
5093 * stop_machine(): we create temporary high priority worker threads,
5094 * but our caller might not have that capability.
5096 int sched_setscheduler_nocheck(struct task_struct
*p
, int policy
,
5097 const struct sched_param
*param
)
5099 return __sched_setscheduler(p
, policy
, param
, false);
5103 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
5105 struct sched_param lparam
;
5106 struct task_struct
*p
;
5109 if (!param
|| pid
< 0)
5111 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
5116 p
= find_process_by_pid(pid
);
5118 retval
= sched_setscheduler(p
, policy
, &lparam
);
5125 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
5126 * @pid: the pid in question.
5127 * @policy: new policy.
5128 * @param: structure containing the new RT priority.
5130 SYSCALL_DEFINE3(sched_setscheduler
, pid_t
, pid
, int, policy
,
5131 struct sched_param __user
*, param
)
5133 /* negative values for policy are not valid */
5137 return do_sched_setscheduler(pid
, policy
, param
);
5141 * sys_sched_setparam - set/change the RT priority of a thread
5142 * @pid: the pid in question.
5143 * @param: structure containing the new RT priority.
5145 SYSCALL_DEFINE2(sched_setparam
, pid_t
, pid
, struct sched_param __user
*, param
)
5147 return do_sched_setscheduler(pid
, -1, param
);
5151 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
5152 * @pid: the pid in question.
5154 SYSCALL_DEFINE1(sched_getscheduler
, pid_t
, pid
)
5156 struct task_struct
*p
;
5164 p
= find_process_by_pid(pid
);
5166 retval
= security_task_getscheduler(p
);
5169 | (p
->sched_reset_on_fork
? SCHED_RESET_ON_FORK
: 0);
5176 * sys_sched_getparam - get the RT priority of a thread
5177 * @pid: the pid in question.
5178 * @param: structure containing the RT priority.
5180 SYSCALL_DEFINE2(sched_getparam
, pid_t
, pid
, struct sched_param __user
*, param
)
5182 struct sched_param lp
;
5183 struct task_struct
*p
;
5186 if (!param
|| pid
< 0)
5190 p
= find_process_by_pid(pid
);
5195 retval
= security_task_getscheduler(p
);
5199 lp
.sched_priority
= p
->rt_priority
;
5203 * This one might sleep, we cannot do it with a spinlock held ...
5205 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
5214 long sched_setaffinity(pid_t pid
, const struct cpumask
*in_mask
)
5216 cpumask_var_t cpus_allowed
, new_mask
;
5217 struct task_struct
*p
;
5223 p
= find_process_by_pid(pid
);
5230 /* Prevent p going away */
5234 if (!alloc_cpumask_var(&cpus_allowed
, GFP_KERNEL
)) {
5238 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
)) {
5240 goto out_free_cpus_allowed
;
5243 if (!check_same_owner(p
) && !task_ns_capable(p
, CAP_SYS_NICE
))
5246 retval
= security_task_setscheduler(p
);
5250 cpuset_cpus_allowed(p
, cpus_allowed
);
5251 cpumask_and(new_mask
, in_mask
, cpus_allowed
);
5253 retval
= set_cpus_allowed_ptr(p
, new_mask
);
5256 cpuset_cpus_allowed(p
, cpus_allowed
);
5257 if (!cpumask_subset(new_mask
, cpus_allowed
)) {
5259 * We must have raced with a concurrent cpuset
5260 * update. Just reset the cpus_allowed to the
5261 * cpuset's cpus_allowed
5263 cpumask_copy(new_mask
, cpus_allowed
);
5268 free_cpumask_var(new_mask
);
5269 out_free_cpus_allowed
:
5270 free_cpumask_var(cpus_allowed
);
5277 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
5278 struct cpumask
*new_mask
)
5280 if (len
< cpumask_size())
5281 cpumask_clear(new_mask
);
5282 else if (len
> cpumask_size())
5283 len
= cpumask_size();
5285 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
5289 * sys_sched_setaffinity - set the cpu affinity of a process
5290 * @pid: pid of the process
5291 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5292 * @user_mask_ptr: user-space pointer to the new cpu mask
5294 SYSCALL_DEFINE3(sched_setaffinity
, pid_t
, pid
, unsigned int, len
,
5295 unsigned long __user
*, user_mask_ptr
)
5297 cpumask_var_t new_mask
;
5300 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
5303 retval
= get_user_cpu_mask(user_mask_ptr
, len
, new_mask
);
5305 retval
= sched_setaffinity(pid
, new_mask
);
5306 free_cpumask_var(new_mask
);
5310 long sched_getaffinity(pid_t pid
, struct cpumask
*mask
)
5312 struct task_struct
*p
;
5313 unsigned long flags
;
5321 p
= find_process_by_pid(pid
);
5325 retval
= security_task_getscheduler(p
);
5329 rq
= task_rq_lock(p
, &flags
);
5330 cpumask_and(mask
, &p
->cpus_allowed
, cpu_online_mask
);
5331 task_rq_unlock(rq
, &flags
);
5341 * sys_sched_getaffinity - get the cpu affinity of a process
5342 * @pid: pid of the process
5343 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5344 * @user_mask_ptr: user-space pointer to hold the current cpu mask
5346 SYSCALL_DEFINE3(sched_getaffinity
, pid_t
, pid
, unsigned int, len
,
5347 unsigned long __user
*, user_mask_ptr
)
5352 if ((len
* BITS_PER_BYTE
) < nr_cpu_ids
)
5354 if (len
& (sizeof(unsigned long)-1))
5357 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
5360 ret
= sched_getaffinity(pid
, mask
);
5362 size_t retlen
= min_t(size_t, len
, cpumask_size());
5364 if (copy_to_user(user_mask_ptr
, mask
, retlen
))
5369 free_cpumask_var(mask
);
5375 * sys_sched_yield - yield the current processor to other threads.
5377 * This function yields the current CPU to other tasks. If there are no
5378 * other threads running on this CPU then this function will return.
5380 SYSCALL_DEFINE0(sched_yield
)
5382 struct rq
*rq
= this_rq_lock();
5384 schedstat_inc(rq
, yld_count
);
5385 current
->sched_class
->yield_task(rq
);
5388 * Since we are going to call schedule() anyway, there's
5389 * no need to preempt or enable interrupts:
5391 __release(rq
->lock
);
5392 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
5393 do_raw_spin_unlock(&rq
->lock
);
5394 preempt_enable_no_resched();
5401 static inline int should_resched(void)
5403 return need_resched() && !(preempt_count() & PREEMPT_ACTIVE
);
5406 static void __cond_resched(void)
5408 add_preempt_count(PREEMPT_ACTIVE
);
5410 sub_preempt_count(PREEMPT_ACTIVE
);
5413 int __sched
_cond_resched(void)
5415 if (should_resched()) {
5421 EXPORT_SYMBOL(_cond_resched
);
5424 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
5425 * call schedule, and on return reacquire the lock.
5427 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
5428 * operations here to prevent schedule() from being called twice (once via
5429 * spin_unlock(), once by hand).
5431 int __cond_resched_lock(spinlock_t
*lock
)
5433 int resched
= should_resched();
5436 lockdep_assert_held(lock
);
5438 if (spin_needbreak(lock
) || resched
) {
5449 EXPORT_SYMBOL(__cond_resched_lock
);
5451 int __sched
__cond_resched_softirq(void)
5453 BUG_ON(!in_softirq());
5455 if (should_resched()) {
5463 EXPORT_SYMBOL(__cond_resched_softirq
);
5466 * yield - yield the current processor to other threads.
5468 * This is a shortcut for kernel-space yielding - it marks the
5469 * thread runnable and calls sys_sched_yield().
5471 void __sched
yield(void)
5473 set_current_state(TASK_RUNNING
);
5476 EXPORT_SYMBOL(yield
);
5479 * yield_to - yield the current processor to another thread in
5480 * your thread group, or accelerate that thread toward the
5481 * processor it's on.
5483 * @preempt: whether task preemption is allowed or not
5485 * It's the caller's job to ensure that the target task struct
5486 * can't go away on us before we can do any checks.
5488 * Returns true if we indeed boosted the target task.
5490 bool __sched
yield_to(struct task_struct
*p
, bool preempt
)
5492 struct task_struct
*curr
= current
;
5493 struct rq
*rq
, *p_rq
;
5494 unsigned long flags
;
5497 local_irq_save(flags
);
5502 double_rq_lock(rq
, p_rq
);
5503 while (task_rq(p
) != p_rq
) {
5504 double_rq_unlock(rq
, p_rq
);
5508 if (!curr
->sched_class
->yield_to_task
)
5511 if (curr
->sched_class
!= p
->sched_class
)
5514 if (task_running(p_rq
, p
) || p
->state
)
5517 yielded
= curr
->sched_class
->yield_to_task(rq
, p
, preempt
);
5519 schedstat_inc(rq
, yld_count
);
5521 * Make p's CPU reschedule; pick_next_entity takes care of
5524 if (preempt
&& rq
!= p_rq
)
5525 resched_task(p_rq
->curr
);
5529 double_rq_unlock(rq
, p_rq
);
5530 local_irq_restore(flags
);
5537 EXPORT_SYMBOL_GPL(yield_to
);
5540 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
5541 * that process accounting knows that this is a task in IO wait state.
5543 void __sched
io_schedule(void)
5545 struct rq
*rq
= raw_rq();
5547 delayacct_blkio_start();
5548 atomic_inc(&rq
->nr_iowait
);
5549 blk_flush_plug(current
);
5550 current
->in_iowait
= 1;
5552 current
->in_iowait
= 0;
5553 atomic_dec(&rq
->nr_iowait
);
5554 delayacct_blkio_end();
5556 EXPORT_SYMBOL(io_schedule
);
5558 long __sched
io_schedule_timeout(long timeout
)
5560 struct rq
*rq
= raw_rq();
5563 delayacct_blkio_start();
5564 atomic_inc(&rq
->nr_iowait
);
5565 blk_flush_plug(current
);
5566 current
->in_iowait
= 1;
5567 ret
= schedule_timeout(timeout
);
5568 current
->in_iowait
= 0;
5569 atomic_dec(&rq
->nr_iowait
);
5570 delayacct_blkio_end();
5575 * sys_sched_get_priority_max - return maximum RT priority.
5576 * @policy: scheduling class.
5578 * this syscall returns the maximum rt_priority that can be used
5579 * by a given scheduling class.
5581 SYSCALL_DEFINE1(sched_get_priority_max
, int, policy
)
5588 ret
= MAX_USER_RT_PRIO
-1;
5600 * sys_sched_get_priority_min - return minimum RT priority.
5601 * @policy: scheduling class.
5603 * this syscall returns the minimum rt_priority that can be used
5604 * by a given scheduling class.
5606 SYSCALL_DEFINE1(sched_get_priority_min
, int, policy
)
5624 * sys_sched_rr_get_interval - return the default timeslice of a process.
5625 * @pid: pid of the process.
5626 * @interval: userspace pointer to the timeslice value.
5628 * this syscall writes the default timeslice value of a given process
5629 * into the user-space timespec buffer. A value of '0' means infinity.
5631 SYSCALL_DEFINE2(sched_rr_get_interval
, pid_t
, pid
,
5632 struct timespec __user
*, interval
)
5634 struct task_struct
*p
;
5635 unsigned int time_slice
;
5636 unsigned long flags
;
5646 p
= find_process_by_pid(pid
);
5650 retval
= security_task_getscheduler(p
);
5654 rq
= task_rq_lock(p
, &flags
);
5655 time_slice
= p
->sched_class
->get_rr_interval(rq
, p
);
5656 task_rq_unlock(rq
, &flags
);
5659 jiffies_to_timespec(time_slice
, &t
);
5660 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
5668 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
5670 void sched_show_task(struct task_struct
*p
)
5672 unsigned long free
= 0;
5675 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
5676 printk(KERN_INFO
"%-15.15s %c", p
->comm
,
5677 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
5678 #if BITS_PER_LONG == 32
5679 if (state
== TASK_RUNNING
)
5680 printk(KERN_CONT
" running ");
5682 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
5684 if (state
== TASK_RUNNING
)
5685 printk(KERN_CONT
" running task ");
5687 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
5689 #ifdef CONFIG_DEBUG_STACK_USAGE
5690 free
= stack_not_used(p
);
5692 printk(KERN_CONT
"%5lu %5d %6d 0x%08lx\n", free
,
5693 task_pid_nr(p
), task_pid_nr(p
->real_parent
),
5694 (unsigned long)task_thread_info(p
)->flags
);
5696 show_stack(p
, NULL
);
5699 void show_state_filter(unsigned long state_filter
)
5701 struct task_struct
*g
, *p
;
5703 #if BITS_PER_LONG == 32
5705 " task PC stack pid father\n");
5708 " task PC stack pid father\n");
5710 read_lock(&tasklist_lock
);
5711 do_each_thread(g
, p
) {
5713 * reset the NMI-timeout, listing all files on a slow
5714 * console might take a lot of time:
5716 touch_nmi_watchdog();
5717 if (!state_filter
|| (p
->state
& state_filter
))
5719 } while_each_thread(g
, p
);
5721 touch_all_softlockup_watchdogs();
5723 #ifdef CONFIG_SCHED_DEBUG
5724 sysrq_sched_debug_show();
5726 read_unlock(&tasklist_lock
);
5728 * Only show locks if all tasks are dumped:
5731 debug_show_all_locks();
5734 void __cpuinit
init_idle_bootup_task(struct task_struct
*idle
)
5736 idle
->sched_class
= &idle_sched_class
;
5740 * init_idle - set up an idle thread for a given CPU
5741 * @idle: task in question
5742 * @cpu: cpu the idle task belongs to
5744 * NOTE: this function does not set the idle thread's NEED_RESCHED
5745 * flag, to make booting more robust.
5747 void __cpuinit
init_idle(struct task_struct
*idle
, int cpu
)
5749 struct rq
*rq
= cpu_rq(cpu
);
5750 unsigned long flags
;
5752 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5755 idle
->state
= TASK_RUNNING
;
5756 idle
->se
.exec_start
= sched_clock();
5758 cpumask_copy(&idle
->cpus_allowed
, cpumask_of(cpu
));
5760 * We're having a chicken and egg problem, even though we are
5761 * holding rq->lock, the cpu isn't yet set to this cpu so the
5762 * lockdep check in task_group() will fail.
5764 * Similar case to sched_fork(). / Alternatively we could
5765 * use task_rq_lock() here and obtain the other rq->lock.
5770 __set_task_cpu(idle
, cpu
);
5773 rq
->curr
= rq
->idle
= idle
;
5774 #if defined(CONFIG_SMP)
5777 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5779 /* Set the preempt count _outside_ the spinlocks! */
5780 #if defined(CONFIG_PREEMPT)
5781 task_thread_info(idle
)->preempt_count
= (idle
->lock_depth
>= 0);
5783 task_thread_info(idle
)->preempt_count
= 0;
5786 * The idle tasks have their own, simple scheduling class:
5788 idle
->sched_class
= &idle_sched_class
;
5789 ftrace_graph_init_idle_task(idle
, cpu
);
5793 * In a system that switches off the HZ timer nohz_cpu_mask
5794 * indicates which cpus entered this state. This is used
5795 * in the rcu update to wait only for active cpus. For system
5796 * which do not switch off the HZ timer nohz_cpu_mask should
5797 * always be CPU_BITS_NONE.
5799 cpumask_var_t nohz_cpu_mask
;
5802 * Increase the granularity value when there are more CPUs,
5803 * because with more CPUs the 'effective latency' as visible
5804 * to users decreases. But the relationship is not linear,
5805 * so pick a second-best guess by going with the log2 of the
5808 * This idea comes from the SD scheduler of Con Kolivas:
5810 static int get_update_sysctl_factor(void)
5812 unsigned int cpus
= min_t(int, num_online_cpus(), 8);
5813 unsigned int factor
;
5815 switch (sysctl_sched_tunable_scaling
) {
5816 case SCHED_TUNABLESCALING_NONE
:
5819 case SCHED_TUNABLESCALING_LINEAR
:
5822 case SCHED_TUNABLESCALING_LOG
:
5824 factor
= 1 + ilog2(cpus
);
5831 static void update_sysctl(void)
5833 unsigned int factor
= get_update_sysctl_factor();
5835 #define SET_SYSCTL(name) \
5836 (sysctl_##name = (factor) * normalized_sysctl_##name)
5837 SET_SYSCTL(sched_min_granularity
);
5838 SET_SYSCTL(sched_latency
);
5839 SET_SYSCTL(sched_wakeup_granularity
);
5843 static inline void sched_init_granularity(void)
5850 * This is how migration works:
5852 * 1) we invoke migration_cpu_stop() on the target CPU using
5854 * 2) stopper starts to run (implicitly forcing the migrated thread
5856 * 3) it checks whether the migrated task is still in the wrong runqueue.
5857 * 4) if it's in the wrong runqueue then the migration thread removes
5858 * it and puts it into the right queue.
5859 * 5) stopper completes and stop_one_cpu() returns and the migration
5864 * Change a given task's CPU affinity. Migrate the thread to a
5865 * proper CPU and schedule it away if the CPU it's executing on
5866 * is removed from the allowed bitmask.
5868 * NOTE: the caller must have a valid reference to the task, the
5869 * task must not exit() & deallocate itself prematurely. The
5870 * call is not atomic; no spinlocks may be held.
5872 int set_cpus_allowed_ptr(struct task_struct
*p
, const struct cpumask
*new_mask
)
5874 unsigned long flags
;
5876 unsigned int dest_cpu
;
5880 * Serialize against TASK_WAKING so that ttwu() and wunt() can
5881 * drop the rq->lock and still rely on ->cpus_allowed.
5884 while (task_is_waking(p
))
5886 rq
= task_rq_lock(p
, &flags
);
5887 if (task_is_waking(p
)) {
5888 task_rq_unlock(rq
, &flags
);
5892 if (!cpumask_intersects(new_mask
, cpu_active_mask
)) {
5897 if (unlikely((p
->flags
& PF_THREAD_BOUND
) && p
!= current
&&
5898 !cpumask_equal(&p
->cpus_allowed
, new_mask
))) {
5903 if (p
->sched_class
->set_cpus_allowed
)
5904 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
5906 cpumask_copy(&p
->cpus_allowed
, new_mask
);
5907 p
->rt
.nr_cpus_allowed
= cpumask_weight(new_mask
);
5910 /* Can the task run on the task's current CPU? If so, we're done */
5911 if (cpumask_test_cpu(task_cpu(p
), new_mask
))
5914 dest_cpu
= cpumask_any_and(cpu_active_mask
, new_mask
);
5915 if (migrate_task(p
, rq
)) {
5916 struct migration_arg arg
= { p
, dest_cpu
};
5917 /* Need help from migration thread: drop lock and wait. */
5918 task_rq_unlock(rq
, &flags
);
5919 stop_one_cpu(cpu_of(rq
), migration_cpu_stop
, &arg
);
5920 tlb_migrate_finish(p
->mm
);
5924 task_rq_unlock(rq
, &flags
);
5928 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
5931 * Move (not current) task off this cpu, onto dest cpu. We're doing
5932 * this because either it can't run here any more (set_cpus_allowed()
5933 * away from this CPU, or CPU going down), or because we're
5934 * attempting to rebalance this task on exec (sched_exec).
5936 * So we race with normal scheduler movements, but that's OK, as long
5937 * as the task is no longer on this CPU.
5939 * Returns non-zero if task was successfully migrated.
5941 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
5943 struct rq
*rq_dest
, *rq_src
;
5946 if (unlikely(!cpu_active(dest_cpu
)))
5949 rq_src
= cpu_rq(src_cpu
);
5950 rq_dest
= cpu_rq(dest_cpu
);
5952 double_rq_lock(rq_src
, rq_dest
);
5953 /* Already moved. */
5954 if (task_cpu(p
) != src_cpu
)
5956 /* Affinity changed (again). */
5957 if (!cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
5961 * If we're not on a rq, the next wake-up will ensure we're
5965 deactivate_task(rq_src
, p
, 0);
5966 set_task_cpu(p
, dest_cpu
);
5967 activate_task(rq_dest
, p
, 0);
5968 check_preempt_curr(rq_dest
, p
, 0);
5973 double_rq_unlock(rq_src
, rq_dest
);
5978 * migration_cpu_stop - this will be executed by a highprio stopper thread
5979 * and performs thread migration by bumping thread off CPU then
5980 * 'pushing' onto another runqueue.
5982 static int migration_cpu_stop(void *data
)
5984 struct migration_arg
*arg
= data
;
5987 * The original target cpu might have gone down and we might
5988 * be on another cpu but it doesn't matter.
5990 local_irq_disable();
5991 __migrate_task(arg
->task
, raw_smp_processor_id(), arg
->dest_cpu
);
5996 #ifdef CONFIG_HOTPLUG_CPU
5999 * Ensures that the idle task is using init_mm right before its cpu goes
6002 void idle_task_exit(void)
6004 struct mm_struct
*mm
= current
->active_mm
;
6006 BUG_ON(cpu_online(smp_processor_id()));
6009 switch_mm(mm
, &init_mm
, current
);
6014 * While a dead CPU has no uninterruptible tasks queued at this point,
6015 * it might still have a nonzero ->nr_uninterruptible counter, because
6016 * for performance reasons the counter is not stricly tracking tasks to
6017 * their home CPUs. So we just add the counter to another CPU's counter,
6018 * to keep the global sum constant after CPU-down:
6020 static void migrate_nr_uninterruptible(struct rq
*rq_src
)
6022 struct rq
*rq_dest
= cpu_rq(cpumask_any(cpu_active_mask
));
6024 rq_dest
->nr_uninterruptible
+= rq_src
->nr_uninterruptible
;
6025 rq_src
->nr_uninterruptible
= 0;
6029 * remove the tasks which were accounted by rq from calc_load_tasks.
6031 static void calc_global_load_remove(struct rq
*rq
)
6033 atomic_long_sub(rq
->calc_load_active
, &calc_load_tasks
);
6034 rq
->calc_load_active
= 0;
6038 * Migrate all tasks from the rq, sleeping tasks will be migrated by
6039 * try_to_wake_up()->select_task_rq().
6041 * Called with rq->lock held even though we'er in stop_machine() and
6042 * there's no concurrency possible, we hold the required locks anyway
6043 * because of lock validation efforts.
6045 static void migrate_tasks(unsigned int dead_cpu
)
6047 struct rq
*rq
= cpu_rq(dead_cpu
);
6048 struct task_struct
*next
, *stop
= rq
->stop
;
6052 * Fudge the rq selection such that the below task selection loop
6053 * doesn't get stuck on the currently eligible stop task.
6055 * We're currently inside stop_machine() and the rq is either stuck
6056 * in the stop_machine_cpu_stop() loop, or we're executing this code,
6057 * either way we should never end up calling schedule() until we're
6064 * There's this thread running, bail when that's the only
6067 if (rq
->nr_running
== 1)
6070 next
= pick_next_task(rq
);
6072 next
->sched_class
->put_prev_task(rq
, next
);
6074 /* Find suitable destination for @next, with force if needed. */
6075 dest_cpu
= select_fallback_rq(dead_cpu
, next
);
6076 raw_spin_unlock(&rq
->lock
);
6078 __migrate_task(next
, dead_cpu
, dest_cpu
);
6080 raw_spin_lock(&rq
->lock
);
6086 #endif /* CONFIG_HOTPLUG_CPU */
6088 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
6090 static struct ctl_table sd_ctl_dir
[] = {
6092 .procname
= "sched_domain",
6098 static struct ctl_table sd_ctl_root
[] = {
6100 .procname
= "kernel",
6102 .child
= sd_ctl_dir
,
6107 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
6109 struct ctl_table
*entry
=
6110 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
6115 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
6117 struct ctl_table
*entry
;
6120 * In the intermediate directories, both the child directory and
6121 * procname are dynamically allocated and could fail but the mode
6122 * will always be set. In the lowest directory the names are
6123 * static strings and all have proc handlers.
6125 for (entry
= *tablep
; entry
->mode
; entry
++) {
6127 sd_free_ctl_entry(&entry
->child
);
6128 if (entry
->proc_handler
== NULL
)
6129 kfree(entry
->procname
);
6137 set_table_entry(struct ctl_table
*entry
,
6138 const char *procname
, void *data
, int maxlen
,
6139 mode_t mode
, proc_handler
*proc_handler
)
6141 entry
->procname
= procname
;
6143 entry
->maxlen
= maxlen
;
6145 entry
->proc_handler
= proc_handler
;
6148 static struct ctl_table
*
6149 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
6151 struct ctl_table
*table
= sd_alloc_ctl_entry(13);
6156 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
6157 sizeof(long), 0644, proc_doulongvec_minmax
);
6158 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
6159 sizeof(long), 0644, proc_doulongvec_minmax
);
6160 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
6161 sizeof(int), 0644, proc_dointvec_minmax
);
6162 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
6163 sizeof(int), 0644, proc_dointvec_minmax
);
6164 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
6165 sizeof(int), 0644, proc_dointvec_minmax
);
6166 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
6167 sizeof(int), 0644, proc_dointvec_minmax
);
6168 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
6169 sizeof(int), 0644, proc_dointvec_minmax
);
6170 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
6171 sizeof(int), 0644, proc_dointvec_minmax
);
6172 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
6173 sizeof(int), 0644, proc_dointvec_minmax
);
6174 set_table_entry(&table
[9], "cache_nice_tries",
6175 &sd
->cache_nice_tries
,
6176 sizeof(int), 0644, proc_dointvec_minmax
);
6177 set_table_entry(&table
[10], "flags", &sd
->flags
,
6178 sizeof(int), 0644, proc_dointvec_minmax
);
6179 set_table_entry(&table
[11], "name", sd
->name
,
6180 CORENAME_MAX_SIZE
, 0444, proc_dostring
);
6181 /* &table[12] is terminator */
6186 static ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
6188 struct ctl_table
*entry
, *table
;
6189 struct sched_domain
*sd
;
6190 int domain_num
= 0, i
;
6193 for_each_domain(cpu
, sd
)
6195 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
6200 for_each_domain(cpu
, sd
) {
6201 snprintf(buf
, 32, "domain%d", i
);
6202 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
6204 entry
->child
= sd_alloc_ctl_domain_table(sd
);
6211 static struct ctl_table_header
*sd_sysctl_header
;
6212 static void register_sched_domain_sysctl(void)
6214 int i
, cpu_num
= num_possible_cpus();
6215 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
6218 WARN_ON(sd_ctl_dir
[0].child
);
6219 sd_ctl_dir
[0].child
= entry
;
6224 for_each_possible_cpu(i
) {
6225 snprintf(buf
, 32, "cpu%d", i
);
6226 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
6228 entry
->child
= sd_alloc_ctl_cpu_table(i
);
6232 WARN_ON(sd_sysctl_header
);
6233 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
6236 /* may be called multiple times per register */
6237 static void unregister_sched_domain_sysctl(void)
6239 if (sd_sysctl_header
)
6240 unregister_sysctl_table(sd_sysctl_header
);
6241 sd_sysctl_header
= NULL
;
6242 if (sd_ctl_dir
[0].child
)
6243 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
6246 static void register_sched_domain_sysctl(void)
6249 static void unregister_sched_domain_sysctl(void)
6254 static void set_rq_online(struct rq
*rq
)
6257 const struct sched_class
*class;
6259 cpumask_set_cpu(rq
->cpu
, rq
->rd
->online
);
6262 for_each_class(class) {
6263 if (class->rq_online
)
6264 class->rq_online(rq
);
6269 static void set_rq_offline(struct rq
*rq
)
6272 const struct sched_class
*class;
6274 for_each_class(class) {
6275 if (class->rq_offline
)
6276 class->rq_offline(rq
);
6279 cpumask_clear_cpu(rq
->cpu
, rq
->rd
->online
);
6285 * migration_call - callback that gets triggered when a CPU is added.
6286 * Here we can start up the necessary migration thread for the new CPU.
6288 static int __cpuinit
6289 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
6291 int cpu
= (long)hcpu
;
6292 unsigned long flags
;
6293 struct rq
*rq
= cpu_rq(cpu
);
6295 switch (action
& ~CPU_TASKS_FROZEN
) {
6297 case CPU_UP_PREPARE
:
6298 rq
->calc_load_update
= calc_load_update
;
6302 /* Update our root-domain */
6303 raw_spin_lock_irqsave(&rq
->lock
, flags
);
6305 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
6309 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
6312 #ifdef CONFIG_HOTPLUG_CPU
6314 /* Update our root-domain */
6315 raw_spin_lock_irqsave(&rq
->lock
, flags
);
6317 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
6321 BUG_ON(rq
->nr_running
!= 1); /* the migration thread */
6322 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
6324 migrate_nr_uninterruptible(rq
);
6325 calc_global_load_remove(rq
);
6330 update_max_interval();
6336 * Register at high priority so that task migration (migrate_all_tasks)
6337 * happens before everything else. This has to be lower priority than
6338 * the notifier in the perf_event subsystem, though.
6340 static struct notifier_block __cpuinitdata migration_notifier
= {
6341 .notifier_call
= migration_call
,
6342 .priority
= CPU_PRI_MIGRATION
,
6345 static int __cpuinit
sched_cpu_active(struct notifier_block
*nfb
,
6346 unsigned long action
, void *hcpu
)
6348 switch (action
& ~CPU_TASKS_FROZEN
) {
6350 case CPU_DOWN_FAILED
:
6351 set_cpu_active((long)hcpu
, true);
6358 static int __cpuinit
sched_cpu_inactive(struct notifier_block
*nfb
,
6359 unsigned long action
, void *hcpu
)
6361 switch (action
& ~CPU_TASKS_FROZEN
) {
6362 case CPU_DOWN_PREPARE
:
6363 set_cpu_active((long)hcpu
, false);
6370 static int __init
migration_init(void)
6372 void *cpu
= (void *)(long)smp_processor_id();
6375 /* Initialize migration for the boot CPU */
6376 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
6377 BUG_ON(err
== NOTIFY_BAD
);
6378 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
6379 register_cpu_notifier(&migration_notifier
);
6381 /* Register cpu active notifiers */
6382 cpu_notifier(sched_cpu_active
, CPU_PRI_SCHED_ACTIVE
);
6383 cpu_notifier(sched_cpu_inactive
, CPU_PRI_SCHED_INACTIVE
);
6387 early_initcall(migration_init
);
6392 #ifdef CONFIG_SCHED_DEBUG
6394 static __read_mostly
int sched_domain_debug_enabled
;
6396 static int __init
sched_domain_debug_setup(char *str
)
6398 sched_domain_debug_enabled
= 1;
6402 early_param("sched_debug", sched_domain_debug_setup
);
6404 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
6405 struct cpumask
*groupmask
)
6407 struct sched_group
*group
= sd
->groups
;
6410 cpulist_scnprintf(str
, sizeof(str
), sched_domain_span(sd
));
6411 cpumask_clear(groupmask
);
6413 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
6415 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
6416 printk("does not load-balance\n");
6418 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
6423 printk(KERN_CONT
"span %s level %s\n", str
, sd
->name
);
6425 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
6426 printk(KERN_ERR
"ERROR: domain->span does not contain "
6429 if (!cpumask_test_cpu(cpu
, sched_group_cpus(group
))) {
6430 printk(KERN_ERR
"ERROR: domain->groups does not contain"
6434 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
6438 printk(KERN_ERR
"ERROR: group is NULL\n");
6442 if (!group
->cpu_power
) {
6443 printk(KERN_CONT
"\n");
6444 printk(KERN_ERR
"ERROR: domain->cpu_power not "
6449 if (!cpumask_weight(sched_group_cpus(group
))) {
6450 printk(KERN_CONT
"\n");
6451 printk(KERN_ERR
"ERROR: empty group\n");
6455 if (cpumask_intersects(groupmask
, sched_group_cpus(group
))) {
6456 printk(KERN_CONT
"\n");
6457 printk(KERN_ERR
"ERROR: repeated CPUs\n");
6461 cpumask_or(groupmask
, groupmask
, sched_group_cpus(group
));
6463 cpulist_scnprintf(str
, sizeof(str
), sched_group_cpus(group
));
6465 printk(KERN_CONT
" %s", str
);
6466 if (group
->cpu_power
!= SCHED_LOAD_SCALE
) {
6467 printk(KERN_CONT
" (cpu_power = %d)",
6471 group
= group
->next
;
6472 } while (group
!= sd
->groups
);
6473 printk(KERN_CONT
"\n");
6475 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
6476 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
6479 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
6480 printk(KERN_ERR
"ERROR: parent span is not a superset "
6481 "of domain->span\n");
6485 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
6487 cpumask_var_t groupmask
;
6490 if (!sched_domain_debug_enabled
)
6494 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
6498 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
6500 if (!alloc_cpumask_var(&groupmask
, GFP_KERNEL
)) {
6501 printk(KERN_DEBUG
"Cannot load-balance (out of memory)\n");
6506 if (sched_domain_debug_one(sd
, cpu
, level
, groupmask
))
6513 free_cpumask_var(groupmask
);
6515 #else /* !CONFIG_SCHED_DEBUG */
6516 # define sched_domain_debug(sd, cpu) do { } while (0)
6517 #endif /* CONFIG_SCHED_DEBUG */
6519 static int sd_degenerate(struct sched_domain
*sd
)
6521 if (cpumask_weight(sched_domain_span(sd
)) == 1)
6524 /* Following flags need at least 2 groups */
6525 if (sd
->flags
& (SD_LOAD_BALANCE
|
6526 SD_BALANCE_NEWIDLE
|
6530 SD_SHARE_PKG_RESOURCES
)) {
6531 if (sd
->groups
!= sd
->groups
->next
)
6535 /* Following flags don't use groups */
6536 if (sd
->flags
& (SD_WAKE_AFFINE
))
6543 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
6545 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
6547 if (sd_degenerate(parent
))
6550 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
6553 /* Flags needing groups don't count if only 1 group in parent */
6554 if (parent
->groups
== parent
->groups
->next
) {
6555 pflags
&= ~(SD_LOAD_BALANCE
|
6556 SD_BALANCE_NEWIDLE
|
6560 SD_SHARE_PKG_RESOURCES
);
6561 if (nr_node_ids
== 1)
6562 pflags
&= ~SD_SERIALIZE
;
6564 if (~cflags
& pflags
)
6570 static void free_rootdomain(struct root_domain
*rd
)
6572 synchronize_sched();
6574 cpupri_cleanup(&rd
->cpupri
);
6576 free_cpumask_var(rd
->rto_mask
);
6577 free_cpumask_var(rd
->online
);
6578 free_cpumask_var(rd
->span
);
6582 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
6584 struct root_domain
*old_rd
= NULL
;
6585 unsigned long flags
;
6587 raw_spin_lock_irqsave(&rq
->lock
, flags
);
6592 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
6595 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
6598 * If we dont want to free the old_rt yet then
6599 * set old_rd to NULL to skip the freeing later
6602 if (!atomic_dec_and_test(&old_rd
->refcount
))
6606 atomic_inc(&rd
->refcount
);
6609 cpumask_set_cpu(rq
->cpu
, rd
->span
);
6610 if (cpumask_test_cpu(rq
->cpu
, cpu_active_mask
))
6613 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
6616 free_rootdomain(old_rd
);
6619 static int init_rootdomain(struct root_domain
*rd
)
6621 memset(rd
, 0, sizeof(*rd
));
6623 if (!alloc_cpumask_var(&rd
->span
, GFP_KERNEL
))
6625 if (!alloc_cpumask_var(&rd
->online
, GFP_KERNEL
))
6627 if (!alloc_cpumask_var(&rd
->rto_mask
, GFP_KERNEL
))
6630 if (cpupri_init(&rd
->cpupri
) != 0)
6635 free_cpumask_var(rd
->rto_mask
);
6637 free_cpumask_var(rd
->online
);
6639 free_cpumask_var(rd
->span
);
6644 static void init_defrootdomain(void)
6646 init_rootdomain(&def_root_domain
);
6648 atomic_set(&def_root_domain
.refcount
, 1);
6651 static struct root_domain
*alloc_rootdomain(void)
6653 struct root_domain
*rd
;
6655 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
6659 if (init_rootdomain(rd
) != 0) {
6668 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
6669 * hold the hotplug lock.
6672 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
6674 struct rq
*rq
= cpu_rq(cpu
);
6675 struct sched_domain
*tmp
;
6677 for (tmp
= sd
; tmp
; tmp
= tmp
->parent
)
6678 tmp
->span_weight
= cpumask_weight(sched_domain_span(tmp
));
6680 /* Remove the sched domains which do not contribute to scheduling. */
6681 for (tmp
= sd
; tmp
; ) {
6682 struct sched_domain
*parent
= tmp
->parent
;
6686 if (sd_parent_degenerate(tmp
, parent
)) {
6687 tmp
->parent
= parent
->parent
;
6689 parent
->parent
->child
= tmp
;
6694 if (sd
&& sd_degenerate(sd
)) {
6700 sched_domain_debug(sd
, cpu
);
6702 rq_attach_root(rq
, rd
);
6703 rcu_assign_pointer(rq
->sd
, sd
);
6706 /* cpus with isolated domains */
6707 static cpumask_var_t cpu_isolated_map
;
6709 /* Setup the mask of cpus configured for isolated domains */
6710 static int __init
isolated_cpu_setup(char *str
)
6712 alloc_bootmem_cpumask_var(&cpu_isolated_map
);
6713 cpulist_parse(str
, cpu_isolated_map
);
6717 __setup("isolcpus=", isolated_cpu_setup
);
6720 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
6721 * to a function which identifies what group(along with sched group) a CPU
6722 * belongs to. The return value of group_fn must be a >= 0 and < nr_cpu_ids
6723 * (due to the fact that we keep track of groups covered with a struct cpumask).
6725 * init_sched_build_groups will build a circular linked list of the groups
6726 * covered by the given span, and will set each group's ->cpumask correctly,
6727 * and ->cpu_power to 0.
6730 init_sched_build_groups(const struct cpumask
*span
,
6731 const struct cpumask
*cpu_map
,
6732 int (*group_fn
)(int cpu
, const struct cpumask
*cpu_map
,
6733 struct sched_group
**sg
,
6734 struct cpumask
*tmpmask
),
6735 struct cpumask
*covered
, struct cpumask
*tmpmask
)
6737 struct sched_group
*first
= NULL
, *last
= NULL
;
6740 cpumask_clear(covered
);
6742 for_each_cpu(i
, span
) {
6743 struct sched_group
*sg
;
6744 int group
= group_fn(i
, cpu_map
, &sg
, tmpmask
);
6747 if (cpumask_test_cpu(i
, covered
))
6750 cpumask_clear(sched_group_cpus(sg
));
6753 for_each_cpu(j
, span
) {
6754 if (group_fn(j
, cpu_map
, NULL
, tmpmask
) != group
)
6757 cpumask_set_cpu(j
, covered
);
6758 cpumask_set_cpu(j
, sched_group_cpus(sg
));
6769 #define SD_NODES_PER_DOMAIN 16
6774 * find_next_best_node - find the next node to include in a sched_domain
6775 * @node: node whose sched_domain we're building
6776 * @used_nodes: nodes already in the sched_domain
6778 * Find the next node to include in a given scheduling domain. Simply
6779 * finds the closest node not already in the @used_nodes map.
6781 * Should use nodemask_t.
6783 static int find_next_best_node(int node
, nodemask_t
*used_nodes
)
6785 int i
, n
, val
, min_val
, best_node
= 0;
6789 for (i
= 0; i
< nr_node_ids
; i
++) {
6790 /* Start at @node */
6791 n
= (node
+ i
) % nr_node_ids
;
6793 if (!nr_cpus_node(n
))
6796 /* Skip already used nodes */
6797 if (node_isset(n
, *used_nodes
))
6800 /* Simple min distance search */
6801 val
= node_distance(node
, n
);
6803 if (val
< min_val
) {
6809 node_set(best_node
, *used_nodes
);
6814 * sched_domain_node_span - get a cpumask for a node's sched_domain
6815 * @node: node whose cpumask we're constructing
6816 * @span: resulting cpumask
6818 * Given a node, construct a good cpumask for its sched_domain to span. It
6819 * should be one that prevents unnecessary balancing, but also spreads tasks
6822 static void sched_domain_node_span(int node
, struct cpumask
*span
)
6824 nodemask_t used_nodes
;
6827 cpumask_clear(span
);
6828 nodes_clear(used_nodes
);
6830 cpumask_or(span
, span
, cpumask_of_node(node
));
6831 node_set(node
, used_nodes
);
6833 for (i
= 1; i
< SD_NODES_PER_DOMAIN
; i
++) {
6834 int next_node
= find_next_best_node(node
, &used_nodes
);
6836 cpumask_or(span
, span
, cpumask_of_node(next_node
));
6839 #endif /* CONFIG_NUMA */
6841 int sched_smt_power_savings
= 0, sched_mc_power_savings
= 0;
6844 * The cpus mask in sched_group and sched_domain hangs off the end.
6846 * ( See the the comments in include/linux/sched.h:struct sched_group
6847 * and struct sched_domain. )
6849 struct static_sched_group
{
6850 struct sched_group sg
;
6851 DECLARE_BITMAP(cpus
, CONFIG_NR_CPUS
);
6854 struct static_sched_domain
{
6855 struct sched_domain sd
;
6856 DECLARE_BITMAP(span
, CONFIG_NR_CPUS
);
6862 cpumask_var_t domainspan
;
6863 cpumask_var_t covered
;
6864 cpumask_var_t notcovered
;
6866 cpumask_var_t nodemask
;
6867 cpumask_var_t this_sibling_map
;
6868 cpumask_var_t this_core_map
;
6869 cpumask_var_t this_book_map
;
6870 cpumask_var_t send_covered
;
6871 cpumask_var_t tmpmask
;
6872 struct sched_group
**sched_group_nodes
;
6873 struct root_domain
*rd
;
6877 sa_sched_groups
= 0,
6883 sa_this_sibling_map
,
6885 sa_sched_group_nodes
,
6895 * SMT sched-domains:
6897 #ifdef CONFIG_SCHED_SMT
6898 static DEFINE_PER_CPU(struct static_sched_domain
, cpu_domains
);
6899 static DEFINE_PER_CPU(struct static_sched_group
, sched_groups
);
6902 cpu_to_cpu_group(int cpu
, const struct cpumask
*cpu_map
,
6903 struct sched_group
**sg
, struct cpumask
*unused
)
6906 *sg
= &per_cpu(sched_groups
, cpu
).sg
;
6909 #endif /* CONFIG_SCHED_SMT */
6912 * multi-core sched-domains:
6914 #ifdef CONFIG_SCHED_MC
6915 static DEFINE_PER_CPU(struct static_sched_domain
, core_domains
);
6916 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_core
);
6919 cpu_to_core_group(int cpu
, const struct cpumask
*cpu_map
,
6920 struct sched_group
**sg
, struct cpumask
*mask
)
6923 #ifdef CONFIG_SCHED_SMT
6924 cpumask_and(mask
, topology_thread_cpumask(cpu
), cpu_map
);
6925 group
= cpumask_first(mask
);
6930 *sg
= &per_cpu(sched_group_core
, group
).sg
;
6933 #endif /* CONFIG_SCHED_MC */
6936 * book sched-domains:
6938 #ifdef CONFIG_SCHED_BOOK
6939 static DEFINE_PER_CPU(struct static_sched_domain
, book_domains
);
6940 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_book
);
6943 cpu_to_book_group(int cpu
, const struct cpumask
*cpu_map
,
6944 struct sched_group
**sg
, struct cpumask
*mask
)
6947 #ifdef CONFIG_SCHED_MC
6948 cpumask_and(mask
, cpu_coregroup_mask(cpu
), cpu_map
);
6949 group
= cpumask_first(mask
);
6950 #elif defined(CONFIG_SCHED_SMT)
6951 cpumask_and(mask
, topology_thread_cpumask(cpu
), cpu_map
);
6952 group
= cpumask_first(mask
);
6955 *sg
= &per_cpu(sched_group_book
, group
).sg
;
6958 #endif /* CONFIG_SCHED_BOOK */
6960 static DEFINE_PER_CPU(struct static_sched_domain
, phys_domains
);
6961 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_phys
);
6964 cpu_to_phys_group(int cpu
, const struct cpumask
*cpu_map
,
6965 struct sched_group
**sg
, struct cpumask
*mask
)
6968 #ifdef CONFIG_SCHED_BOOK
6969 cpumask_and(mask
, cpu_book_mask(cpu
), cpu_map
);
6970 group
= cpumask_first(mask
);
6971 #elif defined(CONFIG_SCHED_MC)
6972 cpumask_and(mask
, cpu_coregroup_mask(cpu
), cpu_map
);
6973 group
= cpumask_first(mask
);
6974 #elif defined(CONFIG_SCHED_SMT)
6975 cpumask_and(mask
, topology_thread_cpumask(cpu
), cpu_map
);
6976 group
= cpumask_first(mask
);
6981 *sg
= &per_cpu(sched_group_phys
, group
).sg
;
6987 * The init_sched_build_groups can't handle what we want to do with node
6988 * groups, so roll our own. Now each node has its own list of groups which
6989 * gets dynamically allocated.
6991 static DEFINE_PER_CPU(struct static_sched_domain
, node_domains
);
6992 static struct sched_group
***sched_group_nodes_bycpu
;
6994 static DEFINE_PER_CPU(struct static_sched_domain
, allnodes_domains
);
6995 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_allnodes
);
6997 static int cpu_to_allnodes_group(int cpu
, const struct cpumask
*cpu_map
,
6998 struct sched_group
**sg
,
6999 struct cpumask
*nodemask
)
7003 cpumask_and(nodemask
, cpumask_of_node(cpu_to_node(cpu
)), cpu_map
);
7004 group
= cpumask_first(nodemask
);
7007 *sg
= &per_cpu(sched_group_allnodes
, group
).sg
;
7011 static void init_numa_sched_groups_power(struct sched_group
*group_head
)
7013 struct sched_group
*sg
= group_head
;
7019 for_each_cpu(j
, sched_group_cpus(sg
)) {
7020 struct sched_domain
*sd
;
7022 sd
= &per_cpu(phys_domains
, j
).sd
;
7023 if (j
!= group_first_cpu(sd
->groups
)) {
7025 * Only add "power" once for each
7031 sg
->cpu_power
+= sd
->groups
->cpu_power
;
7034 } while (sg
!= group_head
);
7037 static int build_numa_sched_groups(struct s_data
*d
,
7038 const struct cpumask
*cpu_map
, int num
)
7040 struct sched_domain
*sd
;
7041 struct sched_group
*sg
, *prev
;
7044 cpumask_clear(d
->covered
);
7045 cpumask_and(d
->nodemask
, cpumask_of_node(num
), cpu_map
);
7046 if (cpumask_empty(d
->nodemask
)) {
7047 d
->sched_group_nodes
[num
] = NULL
;
7051 sched_domain_node_span(num
, d
->domainspan
);
7052 cpumask_and(d
->domainspan
, d
->domainspan
, cpu_map
);
7054 sg
= kmalloc_node(sizeof(struct sched_group
) + cpumask_size(),
7057 printk(KERN_WARNING
"Can not alloc domain group for node %d\n",
7061 d
->sched_group_nodes
[num
] = sg
;
7063 for_each_cpu(j
, d
->nodemask
) {
7064 sd
= &per_cpu(node_domains
, j
).sd
;
7069 cpumask_copy(sched_group_cpus(sg
), d
->nodemask
);
7071 cpumask_or(d
->covered
, d
->covered
, d
->nodemask
);
7074 for (j
= 0; j
< nr_node_ids
; j
++) {
7075 n
= (num
+ j
) % nr_node_ids
;
7076 cpumask_complement(d
->notcovered
, d
->covered
);
7077 cpumask_and(d
->tmpmask
, d
->notcovered
, cpu_map
);
7078 cpumask_and(d
->tmpmask
, d
->tmpmask
, d
->domainspan
);
7079 if (cpumask_empty(d
->tmpmask
))
7081 cpumask_and(d
->tmpmask
, d
->tmpmask
, cpumask_of_node(n
));
7082 if (cpumask_empty(d
->tmpmask
))
7084 sg
= kmalloc_node(sizeof(struct sched_group
) + cpumask_size(),
7088 "Can not alloc domain group for node %d\n", j
);
7092 cpumask_copy(sched_group_cpus(sg
), d
->tmpmask
);
7093 sg
->next
= prev
->next
;
7094 cpumask_or(d
->covered
, d
->covered
, d
->tmpmask
);
7101 #endif /* CONFIG_NUMA */
7104 /* Free memory allocated for various sched_group structures */
7105 static void free_sched_groups(const struct cpumask
*cpu_map
,
7106 struct cpumask
*nodemask
)
7110 for_each_cpu(cpu
, cpu_map
) {
7111 struct sched_group
**sched_group_nodes
7112 = sched_group_nodes_bycpu
[cpu
];
7114 if (!sched_group_nodes
)
7117 for (i
= 0; i
< nr_node_ids
; i
++) {
7118 struct sched_group
*oldsg
, *sg
= sched_group_nodes
[i
];
7120 cpumask_and(nodemask
, cpumask_of_node(i
), cpu_map
);
7121 if (cpumask_empty(nodemask
))
7131 if (oldsg
!= sched_group_nodes
[i
])
7134 kfree(sched_group_nodes
);
7135 sched_group_nodes_bycpu
[cpu
] = NULL
;
7138 #else /* !CONFIG_NUMA */
7139 static void free_sched_groups(const struct cpumask
*cpu_map
,
7140 struct cpumask
*nodemask
)
7143 #endif /* CONFIG_NUMA */
7146 * Initialize sched groups cpu_power.
7148 * cpu_power indicates the capacity of sched group, which is used while
7149 * distributing the load between different sched groups in a sched domain.
7150 * Typically cpu_power for all the groups in a sched domain will be same unless
7151 * there are asymmetries in the topology. If there are asymmetries, group
7152 * having more cpu_power will pickup more load compared to the group having
7155 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
7157 struct sched_domain
*child
;
7158 struct sched_group
*group
;
7162 WARN_ON(!sd
|| !sd
->groups
);
7164 if (cpu
!= group_first_cpu(sd
->groups
))
7167 sd
->groups
->group_weight
= cpumask_weight(sched_group_cpus(sd
->groups
));
7171 sd
->groups
->cpu_power
= 0;
7174 power
= SCHED_LOAD_SCALE
;
7175 weight
= cpumask_weight(sched_domain_span(sd
));
7177 * SMT siblings share the power of a single core.
7178 * Usually multiple threads get a better yield out of
7179 * that one core than a single thread would have,
7180 * reflect that in sd->smt_gain.
7182 if ((sd
->flags
& SD_SHARE_CPUPOWER
) && weight
> 1) {
7183 power
*= sd
->smt_gain
;
7185 power
>>= SCHED_LOAD_SHIFT
;
7187 sd
->groups
->cpu_power
+= power
;
7192 * Add cpu_power of each child group to this groups cpu_power.
7194 group
= child
->groups
;
7196 sd
->groups
->cpu_power
+= group
->cpu_power
;
7197 group
= group
->next
;
7198 } while (group
!= child
->groups
);
7202 * Initializers for schedule domains
7203 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
7206 #ifdef CONFIG_SCHED_DEBUG
7207 # define SD_INIT_NAME(sd, type) sd->name = #type
7209 # define SD_INIT_NAME(sd, type) do { } while (0)
7212 #define SD_INIT(sd, type) sd_init_##type(sd)
7214 #define SD_INIT_FUNC(type) \
7215 static noinline void sd_init_##type(struct sched_domain *sd) \
7217 memset(sd, 0, sizeof(*sd)); \
7218 *sd = SD_##type##_INIT; \
7219 sd->level = SD_LV_##type; \
7220 SD_INIT_NAME(sd, type); \
7225 SD_INIT_FUNC(ALLNODES
)
7228 #ifdef CONFIG_SCHED_SMT
7229 SD_INIT_FUNC(SIBLING
)
7231 #ifdef CONFIG_SCHED_MC
7234 #ifdef CONFIG_SCHED_BOOK
7238 static int default_relax_domain_level
= -1;
7240 static int __init
setup_relax_domain_level(char *str
)
7244 val
= simple_strtoul(str
, NULL
, 0);
7245 if (val
< SD_LV_MAX
)
7246 default_relax_domain_level
= val
;
7250 __setup("relax_domain_level=", setup_relax_domain_level
);
7252 static void set_domain_attribute(struct sched_domain
*sd
,
7253 struct sched_domain_attr
*attr
)
7257 if (!attr
|| attr
->relax_domain_level
< 0) {
7258 if (default_relax_domain_level
< 0)
7261 request
= default_relax_domain_level
;
7263 request
= attr
->relax_domain_level
;
7264 if (request
< sd
->level
) {
7265 /* turn off idle balance on this domain */
7266 sd
->flags
&= ~(SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
7268 /* turn on idle balance on this domain */
7269 sd
->flags
|= (SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
7273 static void __free_domain_allocs(struct s_data
*d
, enum s_alloc what
,
7274 const struct cpumask
*cpu_map
)
7277 case sa_sched_groups
:
7278 free_sched_groups(cpu_map
, d
->tmpmask
); /* fall through */
7279 d
->sched_group_nodes
= NULL
;
7281 free_rootdomain(d
->rd
); /* fall through */
7283 free_cpumask_var(d
->tmpmask
); /* fall through */
7284 case sa_send_covered
:
7285 free_cpumask_var(d
->send_covered
); /* fall through */
7286 case sa_this_book_map
:
7287 free_cpumask_var(d
->this_book_map
); /* fall through */
7288 case sa_this_core_map
:
7289 free_cpumask_var(d
->this_core_map
); /* fall through */
7290 case sa_this_sibling_map
:
7291 free_cpumask_var(d
->this_sibling_map
); /* fall through */
7293 free_cpumask_var(d
->nodemask
); /* fall through */
7294 case sa_sched_group_nodes
:
7296 kfree(d
->sched_group_nodes
); /* fall through */
7298 free_cpumask_var(d
->notcovered
); /* fall through */
7300 free_cpumask_var(d
->covered
); /* fall through */
7302 free_cpumask_var(d
->domainspan
); /* fall through */
7309 static enum s_alloc
__visit_domain_allocation_hell(struct s_data
*d
,
7310 const struct cpumask
*cpu_map
)
7313 if (!alloc_cpumask_var(&d
->domainspan
, GFP_KERNEL
))
7315 if (!alloc_cpumask_var(&d
->covered
, GFP_KERNEL
))
7316 return sa_domainspan
;
7317 if (!alloc_cpumask_var(&d
->notcovered
, GFP_KERNEL
))
7319 /* Allocate the per-node list of sched groups */
7320 d
->sched_group_nodes
= kcalloc(nr_node_ids
,
7321 sizeof(struct sched_group
*), GFP_KERNEL
);
7322 if (!d
->sched_group_nodes
) {
7323 printk(KERN_WARNING
"Can not alloc sched group node list\n");
7324 return sa_notcovered
;
7326 sched_group_nodes_bycpu
[cpumask_first(cpu_map
)] = d
->sched_group_nodes
;
7328 if (!alloc_cpumask_var(&d
->nodemask
, GFP_KERNEL
))
7329 return sa_sched_group_nodes
;
7330 if (!alloc_cpumask_var(&d
->this_sibling_map
, GFP_KERNEL
))
7332 if (!alloc_cpumask_var(&d
->this_core_map
, GFP_KERNEL
))
7333 return sa_this_sibling_map
;
7334 if (!alloc_cpumask_var(&d
->this_book_map
, GFP_KERNEL
))
7335 return sa_this_core_map
;
7336 if (!alloc_cpumask_var(&d
->send_covered
, GFP_KERNEL
))
7337 return sa_this_book_map
;
7338 if (!alloc_cpumask_var(&d
->tmpmask
, GFP_KERNEL
))
7339 return sa_send_covered
;
7340 d
->rd
= alloc_rootdomain();
7342 printk(KERN_WARNING
"Cannot alloc root domain\n");
7345 return sa_rootdomain
;
7348 static struct sched_domain
*__build_numa_sched_domains(struct s_data
*d
,
7349 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
, int i
)
7351 struct sched_domain
*sd
= NULL
;
7353 struct sched_domain
*parent
;
7356 if (cpumask_weight(cpu_map
) >
7357 SD_NODES_PER_DOMAIN
* cpumask_weight(d
->nodemask
)) {
7358 sd
= &per_cpu(allnodes_domains
, i
).sd
;
7359 SD_INIT(sd
, ALLNODES
);
7360 set_domain_attribute(sd
, attr
);
7361 cpumask_copy(sched_domain_span(sd
), cpu_map
);
7362 cpu_to_allnodes_group(i
, cpu_map
, &sd
->groups
, d
->tmpmask
);
7367 sd
= &per_cpu(node_domains
, i
).sd
;
7369 set_domain_attribute(sd
, attr
);
7370 sched_domain_node_span(cpu_to_node(i
), sched_domain_span(sd
));
7371 sd
->parent
= parent
;
7374 cpumask_and(sched_domain_span(sd
), sched_domain_span(sd
), cpu_map
);
7379 static struct sched_domain
*__build_cpu_sched_domain(struct s_data
*d
,
7380 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
7381 struct sched_domain
*parent
, int i
)
7383 struct sched_domain
*sd
;
7384 sd
= &per_cpu(phys_domains
, i
).sd
;
7386 set_domain_attribute(sd
, attr
);
7387 cpumask_copy(sched_domain_span(sd
), d
->nodemask
);
7388 sd
->parent
= parent
;
7391 cpu_to_phys_group(i
, cpu_map
, &sd
->groups
, d
->tmpmask
);
7395 static struct sched_domain
*__build_book_sched_domain(struct s_data
*d
,
7396 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
7397 struct sched_domain
*parent
, int i
)
7399 struct sched_domain
*sd
= parent
;
7400 #ifdef CONFIG_SCHED_BOOK
7401 sd
= &per_cpu(book_domains
, i
).sd
;
7403 set_domain_attribute(sd
, attr
);
7404 cpumask_and(sched_domain_span(sd
), cpu_map
, cpu_book_mask(i
));
7405 sd
->parent
= parent
;
7407 cpu_to_book_group(i
, cpu_map
, &sd
->groups
, d
->tmpmask
);
7412 static struct sched_domain
*__build_mc_sched_domain(struct s_data
*d
,
7413 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
7414 struct sched_domain
*parent
, int i
)
7416 struct sched_domain
*sd
= parent
;
7417 #ifdef CONFIG_SCHED_MC
7418 sd
= &per_cpu(core_domains
, i
).sd
;
7420 set_domain_attribute(sd
, attr
);
7421 cpumask_and(sched_domain_span(sd
), cpu_map
, cpu_coregroup_mask(i
));
7422 sd
->parent
= parent
;
7424 cpu_to_core_group(i
, cpu_map
, &sd
->groups
, d
->tmpmask
);
7429 static struct sched_domain
*__build_smt_sched_domain(struct s_data
*d
,
7430 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
7431 struct sched_domain
*parent
, int i
)
7433 struct sched_domain
*sd
= parent
;
7434 #ifdef CONFIG_SCHED_SMT
7435 sd
= &per_cpu(cpu_domains
, i
).sd
;
7436 SD_INIT(sd
, SIBLING
);
7437 set_domain_attribute(sd
, attr
);
7438 cpumask_and(sched_domain_span(sd
), cpu_map
, topology_thread_cpumask(i
));
7439 sd
->parent
= parent
;
7441 cpu_to_cpu_group(i
, cpu_map
, &sd
->groups
, d
->tmpmask
);
7446 static void build_sched_groups(struct s_data
*d
, enum sched_domain_level l
,
7447 const struct cpumask
*cpu_map
, int cpu
)
7450 #ifdef CONFIG_SCHED_SMT
7451 case SD_LV_SIBLING
: /* set up CPU (sibling) groups */
7452 cpumask_and(d
->this_sibling_map
, cpu_map
,
7453 topology_thread_cpumask(cpu
));
7454 if (cpu
== cpumask_first(d
->this_sibling_map
))
7455 init_sched_build_groups(d
->this_sibling_map
, cpu_map
,
7457 d
->send_covered
, d
->tmpmask
);
7460 #ifdef CONFIG_SCHED_MC
7461 case SD_LV_MC
: /* set up multi-core groups */
7462 cpumask_and(d
->this_core_map
, cpu_map
, cpu_coregroup_mask(cpu
));
7463 if (cpu
== cpumask_first(d
->this_core_map
))
7464 init_sched_build_groups(d
->this_core_map
, cpu_map
,
7466 d
->send_covered
, d
->tmpmask
);
7469 #ifdef CONFIG_SCHED_BOOK
7470 case SD_LV_BOOK
: /* set up book groups */
7471 cpumask_and(d
->this_book_map
, cpu_map
, cpu_book_mask(cpu
));
7472 if (cpu
== cpumask_first(d
->this_book_map
))
7473 init_sched_build_groups(d
->this_book_map
, cpu_map
,
7475 d
->send_covered
, d
->tmpmask
);
7478 case SD_LV_CPU
: /* set up physical groups */
7479 cpumask_and(d
->nodemask
, cpumask_of_node(cpu
), cpu_map
);
7480 if (!cpumask_empty(d
->nodemask
))
7481 init_sched_build_groups(d
->nodemask
, cpu_map
,
7483 d
->send_covered
, d
->tmpmask
);
7486 case SD_LV_ALLNODES
:
7487 init_sched_build_groups(cpu_map
, cpu_map
, &cpu_to_allnodes_group
,
7488 d
->send_covered
, d
->tmpmask
);
7497 * Build sched domains for a given set of cpus and attach the sched domains
7498 * to the individual cpus
7500 static int __build_sched_domains(const struct cpumask
*cpu_map
,
7501 struct sched_domain_attr
*attr
)
7503 enum s_alloc alloc_state
= sa_none
;
7505 struct sched_domain
*sd
;
7511 alloc_state
= __visit_domain_allocation_hell(&d
, cpu_map
);
7512 if (alloc_state
!= sa_rootdomain
)
7514 alloc_state
= sa_sched_groups
;
7517 * Set up domains for cpus specified by the cpu_map.
7519 for_each_cpu(i
, cpu_map
) {
7520 cpumask_and(d
.nodemask
, cpumask_of_node(cpu_to_node(i
)),
7523 sd
= __build_numa_sched_domains(&d
, cpu_map
, attr
, i
);
7524 sd
= __build_cpu_sched_domain(&d
, cpu_map
, attr
, sd
, i
);
7525 sd
= __build_book_sched_domain(&d
, cpu_map
, attr
, sd
, i
);
7526 sd
= __build_mc_sched_domain(&d
, cpu_map
, attr
, sd
, i
);
7527 sd
= __build_smt_sched_domain(&d
, cpu_map
, attr
, sd
, i
);
7530 for_each_cpu(i
, cpu_map
) {
7531 build_sched_groups(&d
, SD_LV_SIBLING
, cpu_map
, i
);
7532 build_sched_groups(&d
, SD_LV_BOOK
, cpu_map
, i
);
7533 build_sched_groups(&d
, SD_LV_MC
, cpu_map
, i
);
7536 /* Set up physical groups */
7537 for (i
= 0; i
< nr_node_ids
; i
++)
7538 build_sched_groups(&d
, SD_LV_CPU
, cpu_map
, i
);
7541 /* Set up node groups */
7543 build_sched_groups(&d
, SD_LV_ALLNODES
, cpu_map
, 0);
7545 for (i
= 0; i
< nr_node_ids
; i
++)
7546 if (build_numa_sched_groups(&d
, cpu_map
, i
))
7550 /* Calculate CPU power for physical packages and nodes */
7551 #ifdef CONFIG_SCHED_SMT
7552 for_each_cpu(i
, cpu_map
) {
7553 sd
= &per_cpu(cpu_domains
, i
).sd
;
7554 init_sched_groups_power(i
, sd
);
7557 #ifdef CONFIG_SCHED_MC
7558 for_each_cpu(i
, cpu_map
) {
7559 sd
= &per_cpu(core_domains
, i
).sd
;
7560 init_sched_groups_power(i
, sd
);
7563 #ifdef CONFIG_SCHED_BOOK
7564 for_each_cpu(i
, cpu_map
) {
7565 sd
= &per_cpu(book_domains
, i
).sd
;
7566 init_sched_groups_power(i
, sd
);
7570 for_each_cpu(i
, cpu_map
) {
7571 sd
= &per_cpu(phys_domains
, i
).sd
;
7572 init_sched_groups_power(i
, sd
);
7576 for (i
= 0; i
< nr_node_ids
; i
++)
7577 init_numa_sched_groups_power(d
.sched_group_nodes
[i
]);
7579 if (d
.sd_allnodes
) {
7580 struct sched_group
*sg
;
7582 cpu_to_allnodes_group(cpumask_first(cpu_map
), cpu_map
, &sg
,
7584 init_numa_sched_groups_power(sg
);
7588 /* Attach the domains */
7589 for_each_cpu(i
, cpu_map
) {
7590 #ifdef CONFIG_SCHED_SMT
7591 sd
= &per_cpu(cpu_domains
, i
).sd
;
7592 #elif defined(CONFIG_SCHED_MC)
7593 sd
= &per_cpu(core_domains
, i
).sd
;
7594 #elif defined(CONFIG_SCHED_BOOK)
7595 sd
= &per_cpu(book_domains
, i
).sd
;
7597 sd
= &per_cpu(phys_domains
, i
).sd
;
7599 cpu_attach_domain(sd
, d
.rd
, i
);
7602 d
.sched_group_nodes
= NULL
; /* don't free this we still need it */
7603 __free_domain_allocs(&d
, sa_tmpmask
, cpu_map
);
7607 __free_domain_allocs(&d
, alloc_state
, cpu_map
);
7611 static int build_sched_domains(const struct cpumask
*cpu_map
)
7613 return __build_sched_domains(cpu_map
, NULL
);
7616 static cpumask_var_t
*doms_cur
; /* current sched domains */
7617 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
7618 static struct sched_domain_attr
*dattr_cur
;
7619 /* attribues of custom domains in 'doms_cur' */
7622 * Special case: If a kmalloc of a doms_cur partition (array of
7623 * cpumask) fails, then fallback to a single sched domain,
7624 * as determined by the single cpumask fallback_doms.
7626 static cpumask_var_t fallback_doms
;
7629 * arch_update_cpu_topology lets virtualized architectures update the
7630 * cpu core maps. It is supposed to return 1 if the topology changed
7631 * or 0 if it stayed the same.
7633 int __attribute__((weak
)) arch_update_cpu_topology(void)
7638 cpumask_var_t
*alloc_sched_domains(unsigned int ndoms
)
7641 cpumask_var_t
*doms
;
7643 doms
= kmalloc(sizeof(*doms
) * ndoms
, GFP_KERNEL
);
7646 for (i
= 0; i
< ndoms
; i
++) {
7647 if (!alloc_cpumask_var(&doms
[i
], GFP_KERNEL
)) {
7648 free_sched_domains(doms
, i
);
7655 void free_sched_domains(cpumask_var_t doms
[], unsigned int ndoms
)
7658 for (i
= 0; i
< ndoms
; i
++)
7659 free_cpumask_var(doms
[i
]);
7664 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
7665 * For now this just excludes isolated cpus, but could be used to
7666 * exclude other special cases in the future.
7668 static int arch_init_sched_domains(const struct cpumask
*cpu_map
)
7672 arch_update_cpu_topology();
7674 doms_cur
= alloc_sched_domains(ndoms_cur
);
7676 doms_cur
= &fallback_doms
;
7677 cpumask_andnot(doms_cur
[0], cpu_map
, cpu_isolated_map
);
7679 err
= build_sched_domains(doms_cur
[0]);
7680 register_sched_domain_sysctl();
7685 static void arch_destroy_sched_domains(const struct cpumask
*cpu_map
,
7686 struct cpumask
*tmpmask
)
7688 free_sched_groups(cpu_map
, tmpmask
);
7692 * Detach sched domains from a group of cpus specified in cpu_map
7693 * These cpus will now be attached to the NULL domain
7695 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
7697 /* Save because hotplug lock held. */
7698 static DECLARE_BITMAP(tmpmask
, CONFIG_NR_CPUS
);
7701 for_each_cpu(i
, cpu_map
)
7702 cpu_attach_domain(NULL
, &def_root_domain
, i
);
7703 synchronize_sched();
7704 arch_destroy_sched_domains(cpu_map
, to_cpumask(tmpmask
));
7707 /* handle null as "default" */
7708 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
7709 struct sched_domain_attr
*new, int idx_new
)
7711 struct sched_domain_attr tmp
;
7718 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
7719 new ? (new + idx_new
) : &tmp
,
7720 sizeof(struct sched_domain_attr
));
7724 * Partition sched domains as specified by the 'ndoms_new'
7725 * cpumasks in the array doms_new[] of cpumasks. This compares
7726 * doms_new[] to the current sched domain partitioning, doms_cur[].
7727 * It destroys each deleted domain and builds each new domain.
7729 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
7730 * The masks don't intersect (don't overlap.) We should setup one
7731 * sched domain for each mask. CPUs not in any of the cpumasks will
7732 * not be load balanced. If the same cpumask appears both in the
7733 * current 'doms_cur' domains and in the new 'doms_new', we can leave
7736 * The passed in 'doms_new' should be allocated using
7737 * alloc_sched_domains. This routine takes ownership of it and will
7738 * free_sched_domains it when done with it. If the caller failed the
7739 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
7740 * and partition_sched_domains() will fallback to the single partition
7741 * 'fallback_doms', it also forces the domains to be rebuilt.
7743 * If doms_new == NULL it will be replaced with cpu_online_mask.
7744 * ndoms_new == 0 is a special case for destroying existing domains,
7745 * and it will not create the default domain.
7747 * Call with hotplug lock held
7749 void partition_sched_domains(int ndoms_new
, cpumask_var_t doms_new
[],
7750 struct sched_domain_attr
*dattr_new
)
7755 mutex_lock(&sched_domains_mutex
);
7757 /* always unregister in case we don't destroy any domains */
7758 unregister_sched_domain_sysctl();
7760 /* Let architecture update cpu core mappings. */
7761 new_topology
= arch_update_cpu_topology();
7763 n
= doms_new
? ndoms_new
: 0;
7765 /* Destroy deleted domains */
7766 for (i
= 0; i
< ndoms_cur
; i
++) {
7767 for (j
= 0; j
< n
&& !new_topology
; j
++) {
7768 if (cpumask_equal(doms_cur
[i
], doms_new
[j
])
7769 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
7772 /* no match - a current sched domain not in new doms_new[] */
7773 detach_destroy_domains(doms_cur
[i
]);
7778 if (doms_new
== NULL
) {
7780 doms_new
= &fallback_doms
;
7781 cpumask_andnot(doms_new
[0], cpu_active_mask
, cpu_isolated_map
);
7782 WARN_ON_ONCE(dattr_new
);
7785 /* Build new domains */
7786 for (i
= 0; i
< ndoms_new
; i
++) {
7787 for (j
= 0; j
< ndoms_cur
&& !new_topology
; j
++) {
7788 if (cpumask_equal(doms_new
[i
], doms_cur
[j
])
7789 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
7792 /* no match - add a new doms_new */
7793 __build_sched_domains(doms_new
[i
],
7794 dattr_new
? dattr_new
+ i
: NULL
);
7799 /* Remember the new sched domains */
7800 if (doms_cur
!= &fallback_doms
)
7801 free_sched_domains(doms_cur
, ndoms_cur
);
7802 kfree(dattr_cur
); /* kfree(NULL) is safe */
7803 doms_cur
= doms_new
;
7804 dattr_cur
= dattr_new
;
7805 ndoms_cur
= ndoms_new
;
7807 register_sched_domain_sysctl();
7809 mutex_unlock(&sched_domains_mutex
);
7812 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
7813 static void arch_reinit_sched_domains(void)
7817 /* Destroy domains first to force the rebuild */
7818 partition_sched_domains(0, NULL
, NULL
);
7820 rebuild_sched_domains();
7824 static ssize_t
sched_power_savings_store(const char *buf
, size_t count
, int smt
)
7826 unsigned int level
= 0;
7828 if (sscanf(buf
, "%u", &level
) != 1)
7832 * level is always be positive so don't check for
7833 * level < POWERSAVINGS_BALANCE_NONE which is 0
7834 * What happens on 0 or 1 byte write,
7835 * need to check for count as well?
7838 if (level
>= MAX_POWERSAVINGS_BALANCE_LEVELS
)
7842 sched_smt_power_savings
= level
;
7844 sched_mc_power_savings
= level
;
7846 arch_reinit_sched_domains();
7851 #ifdef CONFIG_SCHED_MC
7852 static ssize_t
sched_mc_power_savings_show(struct sysdev_class
*class,
7853 struct sysdev_class_attribute
*attr
,
7856 return sprintf(page
, "%u\n", sched_mc_power_savings
);
7858 static ssize_t
sched_mc_power_savings_store(struct sysdev_class
*class,
7859 struct sysdev_class_attribute
*attr
,
7860 const char *buf
, size_t count
)
7862 return sched_power_savings_store(buf
, count
, 0);
7864 static SYSDEV_CLASS_ATTR(sched_mc_power_savings
, 0644,
7865 sched_mc_power_savings_show
,
7866 sched_mc_power_savings_store
);
7869 #ifdef CONFIG_SCHED_SMT
7870 static ssize_t
sched_smt_power_savings_show(struct sysdev_class
*dev
,
7871 struct sysdev_class_attribute
*attr
,
7874 return sprintf(page
, "%u\n", sched_smt_power_savings
);
7876 static ssize_t
sched_smt_power_savings_store(struct sysdev_class
*dev
,
7877 struct sysdev_class_attribute
*attr
,
7878 const char *buf
, size_t count
)
7880 return sched_power_savings_store(buf
, count
, 1);
7882 static SYSDEV_CLASS_ATTR(sched_smt_power_savings
, 0644,
7883 sched_smt_power_savings_show
,
7884 sched_smt_power_savings_store
);
7887 int __init
sched_create_sysfs_power_savings_entries(struct sysdev_class
*cls
)
7891 #ifdef CONFIG_SCHED_SMT
7893 err
= sysfs_create_file(&cls
->kset
.kobj
,
7894 &attr_sched_smt_power_savings
.attr
);
7896 #ifdef CONFIG_SCHED_MC
7897 if (!err
&& mc_capable())
7898 err
= sysfs_create_file(&cls
->kset
.kobj
,
7899 &attr_sched_mc_power_savings
.attr
);
7903 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
7906 * Update cpusets according to cpu_active mask. If cpusets are
7907 * disabled, cpuset_update_active_cpus() becomes a simple wrapper
7908 * around partition_sched_domains().
7910 static int cpuset_cpu_active(struct notifier_block
*nfb
, unsigned long action
,
7913 switch (action
& ~CPU_TASKS_FROZEN
) {
7915 case CPU_DOWN_FAILED
:
7916 cpuset_update_active_cpus();
7923 static int cpuset_cpu_inactive(struct notifier_block
*nfb
, unsigned long action
,
7926 switch (action
& ~CPU_TASKS_FROZEN
) {
7927 case CPU_DOWN_PREPARE
:
7928 cpuset_update_active_cpus();
7935 static int update_runtime(struct notifier_block
*nfb
,
7936 unsigned long action
, void *hcpu
)
7938 int cpu
= (int)(long)hcpu
;
7941 case CPU_DOWN_PREPARE
:
7942 case CPU_DOWN_PREPARE_FROZEN
:
7943 disable_runtime(cpu_rq(cpu
));
7946 case CPU_DOWN_FAILED
:
7947 case CPU_DOWN_FAILED_FROZEN
:
7949 case CPU_ONLINE_FROZEN
:
7950 enable_runtime(cpu_rq(cpu
));
7958 void __init
sched_init_smp(void)
7960 cpumask_var_t non_isolated_cpus
;
7962 alloc_cpumask_var(&non_isolated_cpus
, GFP_KERNEL
);
7963 alloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
7965 #if defined(CONFIG_NUMA)
7966 sched_group_nodes_bycpu
= kzalloc(nr_cpu_ids
* sizeof(void **),
7968 BUG_ON(sched_group_nodes_bycpu
== NULL
);
7971 mutex_lock(&sched_domains_mutex
);
7972 arch_init_sched_domains(cpu_active_mask
);
7973 cpumask_andnot(non_isolated_cpus
, cpu_possible_mask
, cpu_isolated_map
);
7974 if (cpumask_empty(non_isolated_cpus
))
7975 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus
);
7976 mutex_unlock(&sched_domains_mutex
);
7979 hotcpu_notifier(cpuset_cpu_active
, CPU_PRI_CPUSET_ACTIVE
);
7980 hotcpu_notifier(cpuset_cpu_inactive
, CPU_PRI_CPUSET_INACTIVE
);
7982 /* RT runtime code needs to handle some hotplug events */
7983 hotcpu_notifier(update_runtime
, 0);
7987 /* Move init over to a non-isolated CPU */
7988 if (set_cpus_allowed_ptr(current
, non_isolated_cpus
) < 0)
7990 sched_init_granularity();
7991 free_cpumask_var(non_isolated_cpus
);
7993 init_sched_rt_class();
7996 void __init
sched_init_smp(void)
7998 sched_init_granularity();
8000 #endif /* CONFIG_SMP */
8002 const_debug
unsigned int sysctl_timer_migration
= 1;
8004 int in_sched_functions(unsigned long addr
)
8006 return in_lock_functions(addr
) ||
8007 (addr
>= (unsigned long)__sched_text_start
8008 && addr
< (unsigned long)__sched_text_end
);
8011 static void init_cfs_rq(struct cfs_rq
*cfs_rq
, struct rq
*rq
)
8013 cfs_rq
->tasks_timeline
= RB_ROOT
;
8014 INIT_LIST_HEAD(&cfs_rq
->tasks
);
8015 #ifdef CONFIG_FAIR_GROUP_SCHED
8017 /* allow initial update_cfs_load() to truncate */
8019 cfs_rq
->load_stamp
= 1;
8022 cfs_rq
->min_vruntime
= (u64
)(-(1LL << 20));
8025 static void init_rt_rq(struct rt_rq
*rt_rq
, struct rq
*rq
)
8027 struct rt_prio_array
*array
;
8030 array
= &rt_rq
->active
;
8031 for (i
= 0; i
< MAX_RT_PRIO
; i
++) {
8032 INIT_LIST_HEAD(array
->queue
+ i
);
8033 __clear_bit(i
, array
->bitmap
);
8035 /* delimiter for bitsearch: */
8036 __set_bit(MAX_RT_PRIO
, array
->bitmap
);
8038 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
8039 rt_rq
->highest_prio
.curr
= MAX_RT_PRIO
;
8041 rt_rq
->highest_prio
.next
= MAX_RT_PRIO
;
8045 rt_rq
->rt_nr_migratory
= 0;
8046 rt_rq
->overloaded
= 0;
8047 plist_head_init_raw(&rt_rq
->pushable_tasks
, &rq
->lock
);
8051 rt_rq
->rt_throttled
= 0;
8052 rt_rq
->rt_runtime
= 0;
8053 raw_spin_lock_init(&rt_rq
->rt_runtime_lock
);
8055 #ifdef CONFIG_RT_GROUP_SCHED
8056 rt_rq
->rt_nr_boosted
= 0;
8061 #ifdef CONFIG_FAIR_GROUP_SCHED
8062 static void init_tg_cfs_entry(struct task_group
*tg
, struct cfs_rq
*cfs_rq
,
8063 struct sched_entity
*se
, int cpu
,
8064 struct sched_entity
*parent
)
8066 struct rq
*rq
= cpu_rq(cpu
);
8067 tg
->cfs_rq
[cpu
] = cfs_rq
;
8068 init_cfs_rq(cfs_rq
, rq
);
8072 /* se could be NULL for root_task_group */
8077 se
->cfs_rq
= &rq
->cfs
;
8079 se
->cfs_rq
= parent
->my_q
;
8082 update_load_set(&se
->load
, 0);
8083 se
->parent
= parent
;
8087 #ifdef CONFIG_RT_GROUP_SCHED
8088 static void init_tg_rt_entry(struct task_group
*tg
, struct rt_rq
*rt_rq
,
8089 struct sched_rt_entity
*rt_se
, int cpu
,
8090 struct sched_rt_entity
*parent
)
8092 struct rq
*rq
= cpu_rq(cpu
);
8094 tg
->rt_rq
[cpu
] = rt_rq
;
8095 init_rt_rq(rt_rq
, rq
);
8097 rt_rq
->rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
8099 tg
->rt_se
[cpu
] = rt_se
;
8104 rt_se
->rt_rq
= &rq
->rt
;
8106 rt_se
->rt_rq
= parent
->my_q
;
8108 rt_se
->my_q
= rt_rq
;
8109 rt_se
->parent
= parent
;
8110 INIT_LIST_HEAD(&rt_se
->run_list
);
8114 void __init
sched_init(void)
8117 unsigned long alloc_size
= 0, ptr
;
8119 #ifdef CONFIG_FAIR_GROUP_SCHED
8120 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
8122 #ifdef CONFIG_RT_GROUP_SCHED
8123 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
8125 #ifdef CONFIG_CPUMASK_OFFSTACK
8126 alloc_size
+= num_possible_cpus() * cpumask_size();
8129 ptr
= (unsigned long)kzalloc(alloc_size
, GFP_NOWAIT
);
8131 #ifdef CONFIG_FAIR_GROUP_SCHED
8132 root_task_group
.se
= (struct sched_entity
**)ptr
;
8133 ptr
+= nr_cpu_ids
* sizeof(void **);
8135 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
8136 ptr
+= nr_cpu_ids
* sizeof(void **);
8138 #endif /* CONFIG_FAIR_GROUP_SCHED */
8139 #ifdef CONFIG_RT_GROUP_SCHED
8140 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
8141 ptr
+= nr_cpu_ids
* sizeof(void **);
8143 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
8144 ptr
+= nr_cpu_ids
* sizeof(void **);
8146 #endif /* CONFIG_RT_GROUP_SCHED */
8147 #ifdef CONFIG_CPUMASK_OFFSTACK
8148 for_each_possible_cpu(i
) {
8149 per_cpu(load_balance_tmpmask
, i
) = (void *)ptr
;
8150 ptr
+= cpumask_size();
8152 #endif /* CONFIG_CPUMASK_OFFSTACK */
8156 init_defrootdomain();
8159 init_rt_bandwidth(&def_rt_bandwidth
,
8160 global_rt_period(), global_rt_runtime());
8162 #ifdef CONFIG_RT_GROUP_SCHED
8163 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
8164 global_rt_period(), global_rt_runtime());
8165 #endif /* CONFIG_RT_GROUP_SCHED */
8167 #ifdef CONFIG_CGROUP_SCHED
8168 list_add(&root_task_group
.list
, &task_groups
);
8169 INIT_LIST_HEAD(&root_task_group
.children
);
8170 autogroup_init(&init_task
);
8171 #endif /* CONFIG_CGROUP_SCHED */
8173 for_each_possible_cpu(i
) {
8177 raw_spin_lock_init(&rq
->lock
);
8179 rq
->calc_load_active
= 0;
8180 rq
->calc_load_update
= jiffies
+ LOAD_FREQ
;
8181 init_cfs_rq(&rq
->cfs
, rq
);
8182 init_rt_rq(&rq
->rt
, rq
);
8183 #ifdef CONFIG_FAIR_GROUP_SCHED
8184 root_task_group
.shares
= root_task_group_load
;
8185 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
8187 * How much cpu bandwidth does root_task_group get?
8189 * In case of task-groups formed thr' the cgroup filesystem, it
8190 * gets 100% of the cpu resources in the system. This overall
8191 * system cpu resource is divided among the tasks of
8192 * root_task_group and its child task-groups in a fair manner,
8193 * based on each entity's (task or task-group's) weight
8194 * (se->load.weight).
8196 * In other words, if root_task_group has 10 tasks of weight
8197 * 1024) and two child groups A0 and A1 (of weight 1024 each),
8198 * then A0's share of the cpu resource is:
8200 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
8202 * We achieve this by letting root_task_group's tasks sit
8203 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
8205 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, NULL
);
8206 #endif /* CONFIG_FAIR_GROUP_SCHED */
8208 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
8209 #ifdef CONFIG_RT_GROUP_SCHED
8210 INIT_LIST_HEAD(&rq
->leaf_rt_rq_list
);
8211 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, NULL
);
8214 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
8215 rq
->cpu_load
[j
] = 0;
8217 rq
->last_load_update_tick
= jiffies
;
8222 rq
->cpu_power
= SCHED_LOAD_SCALE
;
8223 rq
->post_schedule
= 0;
8224 rq
->active_balance
= 0;
8225 rq
->next_balance
= jiffies
;
8230 rq
->avg_idle
= 2*sysctl_sched_migration_cost
;
8231 rq_attach_root(rq
, &def_root_domain
);
8233 rq
->nohz_balance_kick
= 0;
8234 init_sched_softirq_csd(&per_cpu(remote_sched_softirq_cb
, i
));
8238 atomic_set(&rq
->nr_iowait
, 0);
8241 set_load_weight(&init_task
);
8243 #ifdef CONFIG_PREEMPT_NOTIFIERS
8244 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
8248 open_softirq(SCHED_SOFTIRQ
, run_rebalance_domains
);
8251 #ifdef CONFIG_RT_MUTEXES
8252 plist_head_init_raw(&init_task
.pi_waiters
, &init_task
.pi_lock
);
8256 * The boot idle thread does lazy MMU switching as well:
8258 atomic_inc(&init_mm
.mm_count
);
8259 enter_lazy_tlb(&init_mm
, current
);
8262 * Make us the idle thread. Technically, schedule() should not be
8263 * called from this thread, however somewhere below it might be,
8264 * but because we are the idle thread, we just pick up running again
8265 * when this runqueue becomes "idle".
8267 init_idle(current
, smp_processor_id());
8269 calc_load_update
= jiffies
+ LOAD_FREQ
;
8272 * During early bootup we pretend to be a normal task:
8274 current
->sched_class
= &fair_sched_class
;
8276 /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */
8277 zalloc_cpumask_var(&nohz_cpu_mask
, GFP_NOWAIT
);
8280 zalloc_cpumask_var(&nohz
.idle_cpus_mask
, GFP_NOWAIT
);
8281 alloc_cpumask_var(&nohz
.grp_idle_mask
, GFP_NOWAIT
);
8282 atomic_set(&nohz
.load_balancer
, nr_cpu_ids
);
8283 atomic_set(&nohz
.first_pick_cpu
, nr_cpu_ids
);
8284 atomic_set(&nohz
.second_pick_cpu
, nr_cpu_ids
);
8286 /* May be allocated at isolcpus cmdline parse time */
8287 if (cpu_isolated_map
== NULL
)
8288 zalloc_cpumask_var(&cpu_isolated_map
, GFP_NOWAIT
);
8291 scheduler_running
= 1;
8294 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
8295 static inline int preempt_count_equals(int preempt_offset
)
8297 int nested
= (preempt_count() & ~PREEMPT_ACTIVE
) + rcu_preempt_depth();
8299 return (nested
== preempt_offset
);
8302 void __might_sleep(const char *file
, int line
, int preempt_offset
)
8305 static unsigned long prev_jiffy
; /* ratelimiting */
8307 if ((preempt_count_equals(preempt_offset
) && !irqs_disabled()) ||
8308 system_state
!= SYSTEM_RUNNING
|| oops_in_progress
)
8310 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
8312 prev_jiffy
= jiffies
;
8315 "BUG: sleeping function called from invalid context at %s:%d\n",
8318 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
8319 in_atomic(), irqs_disabled(),
8320 current
->pid
, current
->comm
);
8322 debug_show_held_locks(current
);
8323 if (irqs_disabled())
8324 print_irqtrace_events(current
);
8328 EXPORT_SYMBOL(__might_sleep
);
8331 #ifdef CONFIG_MAGIC_SYSRQ
8332 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
8334 const struct sched_class
*prev_class
= p
->sched_class
;
8335 int old_prio
= p
->prio
;
8338 on_rq
= p
->se
.on_rq
;
8340 deactivate_task(rq
, p
, 0);
8341 __setscheduler(rq
, p
, SCHED_NORMAL
, 0);
8343 activate_task(rq
, p
, 0);
8344 resched_task(rq
->curr
);
8347 check_class_changed(rq
, p
, prev_class
, old_prio
);
8350 void normalize_rt_tasks(void)
8352 struct task_struct
*g
, *p
;
8353 unsigned long flags
;
8356 read_lock_irqsave(&tasklist_lock
, flags
);
8357 do_each_thread(g
, p
) {
8359 * Only normalize user tasks:
8364 p
->se
.exec_start
= 0;
8365 #ifdef CONFIG_SCHEDSTATS
8366 p
->se
.statistics
.wait_start
= 0;
8367 p
->se
.statistics
.sleep_start
= 0;
8368 p
->se
.statistics
.block_start
= 0;
8373 * Renice negative nice level userspace
8376 if (TASK_NICE(p
) < 0 && p
->mm
)
8377 set_user_nice(p
, 0);
8381 raw_spin_lock(&p
->pi_lock
);
8382 rq
= __task_rq_lock(p
);
8384 normalize_task(rq
, p
);
8386 __task_rq_unlock(rq
);
8387 raw_spin_unlock(&p
->pi_lock
);
8388 } while_each_thread(g
, p
);
8390 read_unlock_irqrestore(&tasklist_lock
, flags
);
8393 #endif /* CONFIG_MAGIC_SYSRQ */
8395 #if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
8397 * These functions are only useful for the IA64 MCA handling, or kdb.
8399 * They can only be called when the whole system has been
8400 * stopped - every CPU needs to be quiescent, and no scheduling
8401 * activity can take place. Using them for anything else would
8402 * be a serious bug, and as a result, they aren't even visible
8403 * under any other configuration.
8407 * curr_task - return the current task for a given cpu.
8408 * @cpu: the processor in question.
8410 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
8412 struct task_struct
*curr_task(int cpu
)
8414 return cpu_curr(cpu
);
8417 #endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
8421 * set_curr_task - set the current task for a given cpu.
8422 * @cpu: the processor in question.
8423 * @p: the task pointer to set.
8425 * Description: This function must only be used when non-maskable interrupts
8426 * are serviced on a separate stack. It allows the architecture to switch the
8427 * notion of the current task on a cpu in a non-blocking manner. This function
8428 * must be called with all CPU's synchronized, and interrupts disabled, the
8429 * and caller must save the original value of the current task (see
8430 * curr_task() above) and restore that value before reenabling interrupts and
8431 * re-starting the system.
8433 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
8435 void set_curr_task(int cpu
, struct task_struct
*p
)
8442 #ifdef CONFIG_FAIR_GROUP_SCHED
8443 static void free_fair_sched_group(struct task_group
*tg
)
8447 for_each_possible_cpu(i
) {
8449 kfree(tg
->cfs_rq
[i
]);
8459 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8461 struct cfs_rq
*cfs_rq
;
8462 struct sched_entity
*se
;
8465 tg
->cfs_rq
= kzalloc(sizeof(cfs_rq
) * nr_cpu_ids
, GFP_KERNEL
);
8468 tg
->se
= kzalloc(sizeof(se
) * nr_cpu_ids
, GFP_KERNEL
);
8472 tg
->shares
= NICE_0_LOAD
;
8474 for_each_possible_cpu(i
) {
8475 cfs_rq
= kzalloc_node(sizeof(struct cfs_rq
),
8476 GFP_KERNEL
, cpu_to_node(i
));
8480 se
= kzalloc_node(sizeof(struct sched_entity
),
8481 GFP_KERNEL
, cpu_to_node(i
));
8485 init_tg_cfs_entry(tg
, cfs_rq
, se
, i
, parent
->se
[i
]);
8496 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
8498 struct rq
*rq
= cpu_rq(cpu
);
8499 unsigned long flags
;
8502 * Only empty task groups can be destroyed; so we can speculatively
8503 * check on_list without danger of it being re-added.
8505 if (!tg
->cfs_rq
[cpu
]->on_list
)
8508 raw_spin_lock_irqsave(&rq
->lock
, flags
);
8509 list_del_leaf_cfs_rq(tg
->cfs_rq
[cpu
]);
8510 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
8512 #else /* !CONFG_FAIR_GROUP_SCHED */
8513 static inline void free_fair_sched_group(struct task_group
*tg
)
8518 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8523 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
8526 #endif /* CONFIG_FAIR_GROUP_SCHED */
8528 #ifdef CONFIG_RT_GROUP_SCHED
8529 static void free_rt_sched_group(struct task_group
*tg
)
8533 destroy_rt_bandwidth(&tg
->rt_bandwidth
);
8535 for_each_possible_cpu(i
) {
8537 kfree(tg
->rt_rq
[i
]);
8539 kfree(tg
->rt_se
[i
]);
8547 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8549 struct rt_rq
*rt_rq
;
8550 struct sched_rt_entity
*rt_se
;
8554 tg
->rt_rq
= kzalloc(sizeof(rt_rq
) * nr_cpu_ids
, GFP_KERNEL
);
8557 tg
->rt_se
= kzalloc(sizeof(rt_se
) * nr_cpu_ids
, GFP_KERNEL
);
8561 init_rt_bandwidth(&tg
->rt_bandwidth
,
8562 ktime_to_ns(def_rt_bandwidth
.rt_period
), 0);
8564 for_each_possible_cpu(i
) {
8567 rt_rq
= kzalloc_node(sizeof(struct rt_rq
),
8568 GFP_KERNEL
, cpu_to_node(i
));
8572 rt_se
= kzalloc_node(sizeof(struct sched_rt_entity
),
8573 GFP_KERNEL
, cpu_to_node(i
));
8577 init_tg_rt_entry(tg
, rt_rq
, rt_se
, i
, parent
->rt_se
[i
]);
8587 #else /* !CONFIG_RT_GROUP_SCHED */
8588 static inline void free_rt_sched_group(struct task_group
*tg
)
8593 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8597 #endif /* CONFIG_RT_GROUP_SCHED */
8599 #ifdef CONFIG_CGROUP_SCHED
8600 static void free_sched_group(struct task_group
*tg
)
8602 free_fair_sched_group(tg
);
8603 free_rt_sched_group(tg
);
8608 /* allocate runqueue etc for a new task group */
8609 struct task_group
*sched_create_group(struct task_group
*parent
)
8611 struct task_group
*tg
;
8612 unsigned long flags
;
8614 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
8616 return ERR_PTR(-ENOMEM
);
8618 if (!alloc_fair_sched_group(tg
, parent
))
8621 if (!alloc_rt_sched_group(tg
, parent
))
8624 spin_lock_irqsave(&task_group_lock
, flags
);
8625 list_add_rcu(&tg
->list
, &task_groups
);
8627 WARN_ON(!parent
); /* root should already exist */
8629 tg
->parent
= parent
;
8630 INIT_LIST_HEAD(&tg
->children
);
8631 list_add_rcu(&tg
->siblings
, &parent
->children
);
8632 spin_unlock_irqrestore(&task_group_lock
, flags
);
8637 free_sched_group(tg
);
8638 return ERR_PTR(-ENOMEM
);
8641 /* rcu callback to free various structures associated with a task group */
8642 static void free_sched_group_rcu(struct rcu_head
*rhp
)
8644 /* now it should be safe to free those cfs_rqs */
8645 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
8648 /* Destroy runqueue etc associated with a task group */
8649 void sched_destroy_group(struct task_group
*tg
)
8651 unsigned long flags
;
8654 /* end participation in shares distribution */
8655 for_each_possible_cpu(i
)
8656 unregister_fair_sched_group(tg
, i
);
8658 spin_lock_irqsave(&task_group_lock
, flags
);
8659 list_del_rcu(&tg
->list
);
8660 list_del_rcu(&tg
->siblings
);
8661 spin_unlock_irqrestore(&task_group_lock
, flags
);
8663 /* wait for possible concurrent references to cfs_rqs complete */
8664 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
8667 /* change task's runqueue when it moves between groups.
8668 * The caller of this function should have put the task in its new group
8669 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
8670 * reflect its new group.
8672 void sched_move_task(struct task_struct
*tsk
)
8675 unsigned long flags
;
8678 rq
= task_rq_lock(tsk
, &flags
);
8680 running
= task_current(rq
, tsk
);
8681 on_rq
= tsk
->se
.on_rq
;
8684 dequeue_task(rq
, tsk
, 0);
8685 if (unlikely(running
))
8686 tsk
->sched_class
->put_prev_task(rq
, tsk
);
8688 #ifdef CONFIG_FAIR_GROUP_SCHED
8689 if (tsk
->sched_class
->task_move_group
)
8690 tsk
->sched_class
->task_move_group(tsk
, on_rq
);
8693 set_task_rq(tsk
, task_cpu(tsk
));
8695 if (unlikely(running
))
8696 tsk
->sched_class
->set_curr_task(rq
);
8698 enqueue_task(rq
, tsk
, 0);
8700 task_rq_unlock(rq
, &flags
);
8702 #endif /* CONFIG_CGROUP_SCHED */
8704 #ifdef CONFIG_FAIR_GROUP_SCHED
8705 static DEFINE_MUTEX(shares_mutex
);
8707 int sched_group_set_shares(struct task_group
*tg
, unsigned long shares
)
8710 unsigned long flags
;
8713 * We can't change the weight of the root cgroup.
8718 if (shares
< MIN_SHARES
)
8719 shares
= MIN_SHARES
;
8720 else if (shares
> MAX_SHARES
)
8721 shares
= MAX_SHARES
;
8723 mutex_lock(&shares_mutex
);
8724 if (tg
->shares
== shares
)
8727 tg
->shares
= shares
;
8728 for_each_possible_cpu(i
) {
8729 struct rq
*rq
= cpu_rq(i
);
8730 struct sched_entity
*se
;
8733 /* Propagate contribution to hierarchy */
8734 raw_spin_lock_irqsave(&rq
->lock
, flags
);
8735 for_each_sched_entity(se
)
8736 update_cfs_shares(group_cfs_rq(se
));
8737 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
8741 mutex_unlock(&shares_mutex
);
8745 unsigned long sched_group_shares(struct task_group
*tg
)
8751 #ifdef CONFIG_RT_GROUP_SCHED
8753 * Ensure that the real time constraints are schedulable.
8755 static DEFINE_MUTEX(rt_constraints_mutex
);
8757 static unsigned long to_ratio(u64 period
, u64 runtime
)
8759 if (runtime
== RUNTIME_INF
)
8762 return div64_u64(runtime
<< 20, period
);
8765 /* Must be called with tasklist_lock held */
8766 static inline int tg_has_rt_tasks(struct task_group
*tg
)
8768 struct task_struct
*g
, *p
;
8770 do_each_thread(g
, p
) {
8771 if (rt_task(p
) && rt_rq_of_se(&p
->rt
)->tg
== tg
)
8773 } while_each_thread(g
, p
);
8778 struct rt_schedulable_data
{
8779 struct task_group
*tg
;
8784 static int tg_schedulable(struct task_group
*tg
, void *data
)
8786 struct rt_schedulable_data
*d
= data
;
8787 struct task_group
*child
;
8788 unsigned long total
, sum
= 0;
8789 u64 period
, runtime
;
8791 period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8792 runtime
= tg
->rt_bandwidth
.rt_runtime
;
8795 period
= d
->rt_period
;
8796 runtime
= d
->rt_runtime
;
8800 * Cannot have more runtime than the period.
8802 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
8806 * Ensure we don't starve existing RT tasks.
8808 if (rt_bandwidth_enabled() && !runtime
&& tg_has_rt_tasks(tg
))
8811 total
= to_ratio(period
, runtime
);
8814 * Nobody can have more than the global setting allows.
8816 if (total
> to_ratio(global_rt_period(), global_rt_runtime()))
8820 * The sum of our children's runtime should not exceed our own.
8822 list_for_each_entry_rcu(child
, &tg
->children
, siblings
) {
8823 period
= ktime_to_ns(child
->rt_bandwidth
.rt_period
);
8824 runtime
= child
->rt_bandwidth
.rt_runtime
;
8826 if (child
== d
->tg
) {
8827 period
= d
->rt_period
;
8828 runtime
= d
->rt_runtime
;
8831 sum
+= to_ratio(period
, runtime
);
8840 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
8842 struct rt_schedulable_data data
= {
8844 .rt_period
= period
,
8845 .rt_runtime
= runtime
,
8848 return walk_tg_tree(tg_schedulable
, tg_nop
, &data
);
8851 static int tg_set_bandwidth(struct task_group
*tg
,
8852 u64 rt_period
, u64 rt_runtime
)
8856 mutex_lock(&rt_constraints_mutex
);
8857 read_lock(&tasklist_lock
);
8858 err
= __rt_schedulable(tg
, rt_period
, rt_runtime
);
8862 raw_spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
8863 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
8864 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
8866 for_each_possible_cpu(i
) {
8867 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
8869 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
8870 rt_rq
->rt_runtime
= rt_runtime
;
8871 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
8873 raw_spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
8875 read_unlock(&tasklist_lock
);
8876 mutex_unlock(&rt_constraints_mutex
);
8881 int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
8883 u64 rt_runtime
, rt_period
;
8885 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8886 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
8887 if (rt_runtime_us
< 0)
8888 rt_runtime
= RUNTIME_INF
;
8890 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
8893 long sched_group_rt_runtime(struct task_group
*tg
)
8897 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
8900 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
8901 do_div(rt_runtime_us
, NSEC_PER_USEC
);
8902 return rt_runtime_us
;
8905 int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
8907 u64 rt_runtime
, rt_period
;
8909 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
8910 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
8915 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
8918 long sched_group_rt_period(struct task_group
*tg
)
8922 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8923 do_div(rt_period_us
, NSEC_PER_USEC
);
8924 return rt_period_us
;
8927 static int sched_rt_global_constraints(void)
8929 u64 runtime
, period
;
8932 if (sysctl_sched_rt_period
<= 0)
8935 runtime
= global_rt_runtime();
8936 period
= global_rt_period();
8939 * Sanity check on the sysctl variables.
8941 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
8944 mutex_lock(&rt_constraints_mutex
);
8945 read_lock(&tasklist_lock
);
8946 ret
= __rt_schedulable(NULL
, 0, 0);
8947 read_unlock(&tasklist_lock
);
8948 mutex_unlock(&rt_constraints_mutex
);
8953 int sched_rt_can_attach(struct task_group
*tg
, struct task_struct
*tsk
)
8955 /* Don't accept realtime tasks when there is no way for them to run */
8956 if (rt_task(tsk
) && tg
->rt_bandwidth
.rt_runtime
== 0)
8962 #else /* !CONFIG_RT_GROUP_SCHED */
8963 static int sched_rt_global_constraints(void)
8965 unsigned long flags
;
8968 if (sysctl_sched_rt_period
<= 0)
8972 * There's always some RT tasks in the root group
8973 * -- migration, kstopmachine etc..
8975 if (sysctl_sched_rt_runtime
== 0)
8978 raw_spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
8979 for_each_possible_cpu(i
) {
8980 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
8982 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
8983 rt_rq
->rt_runtime
= global_rt_runtime();
8984 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
8986 raw_spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
8990 #endif /* CONFIG_RT_GROUP_SCHED */
8992 int sched_rt_handler(struct ctl_table
*table
, int write
,
8993 void __user
*buffer
, size_t *lenp
,
8997 int old_period
, old_runtime
;
8998 static DEFINE_MUTEX(mutex
);
9001 old_period
= sysctl_sched_rt_period
;
9002 old_runtime
= sysctl_sched_rt_runtime
;
9004 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
9006 if (!ret
&& write
) {
9007 ret
= sched_rt_global_constraints();
9009 sysctl_sched_rt_period
= old_period
;
9010 sysctl_sched_rt_runtime
= old_runtime
;
9012 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
9013 def_rt_bandwidth
.rt_period
=
9014 ns_to_ktime(global_rt_period());
9017 mutex_unlock(&mutex
);
9022 #ifdef CONFIG_CGROUP_SCHED
9024 /* return corresponding task_group object of a cgroup */
9025 static inline struct task_group
*cgroup_tg(struct cgroup
*cgrp
)
9027 return container_of(cgroup_subsys_state(cgrp
, cpu_cgroup_subsys_id
),
9028 struct task_group
, css
);
9031 static struct cgroup_subsys_state
*
9032 cpu_cgroup_create(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9034 struct task_group
*tg
, *parent
;
9036 if (!cgrp
->parent
) {
9037 /* This is early initialization for the top cgroup */
9038 return &root_task_group
.css
;
9041 parent
= cgroup_tg(cgrp
->parent
);
9042 tg
= sched_create_group(parent
);
9044 return ERR_PTR(-ENOMEM
);
9050 cpu_cgroup_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9052 struct task_group
*tg
= cgroup_tg(cgrp
);
9054 sched_destroy_group(tg
);
9058 cpu_cgroup_can_attach_task(struct cgroup
*cgrp
, struct task_struct
*tsk
)
9060 #ifdef CONFIG_RT_GROUP_SCHED
9061 if (!sched_rt_can_attach(cgroup_tg(cgrp
), tsk
))
9064 /* We don't support RT-tasks being in separate groups */
9065 if (tsk
->sched_class
!= &fair_sched_class
)
9072 cpu_cgroup_can_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
9073 struct task_struct
*tsk
, bool threadgroup
)
9075 int retval
= cpu_cgroup_can_attach_task(cgrp
, tsk
);
9079 struct task_struct
*c
;
9081 list_for_each_entry_rcu(c
, &tsk
->thread_group
, thread_group
) {
9082 retval
= cpu_cgroup_can_attach_task(cgrp
, c
);
9094 cpu_cgroup_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
9095 struct cgroup
*old_cont
, struct task_struct
*tsk
,
9098 sched_move_task(tsk
);
9100 struct task_struct
*c
;
9102 list_for_each_entry_rcu(c
, &tsk
->thread_group
, thread_group
) {
9110 cpu_cgroup_exit(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
9111 struct cgroup
*old_cgrp
, struct task_struct
*task
)
9114 * cgroup_exit() is called in the copy_process() failure path.
9115 * Ignore this case since the task hasn't ran yet, this avoids
9116 * trying to poke a half freed task state from generic code.
9118 if (!(task
->flags
& PF_EXITING
))
9121 sched_move_task(task
);
9124 #ifdef CONFIG_FAIR_GROUP_SCHED
9125 static int cpu_shares_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
9128 return sched_group_set_shares(cgroup_tg(cgrp
), shareval
);
9131 static u64
cpu_shares_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
9133 struct task_group
*tg
= cgroup_tg(cgrp
);
9135 return (u64
) tg
->shares
;
9137 #endif /* CONFIG_FAIR_GROUP_SCHED */
9139 #ifdef CONFIG_RT_GROUP_SCHED
9140 static int cpu_rt_runtime_write(struct cgroup
*cgrp
, struct cftype
*cft
,
9143 return sched_group_set_rt_runtime(cgroup_tg(cgrp
), val
);
9146 static s64
cpu_rt_runtime_read(struct cgroup
*cgrp
, struct cftype
*cft
)
9148 return sched_group_rt_runtime(cgroup_tg(cgrp
));
9151 static int cpu_rt_period_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
9154 return sched_group_set_rt_period(cgroup_tg(cgrp
), rt_period_us
);
9157 static u64
cpu_rt_period_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
9159 return sched_group_rt_period(cgroup_tg(cgrp
));
9161 #endif /* CONFIG_RT_GROUP_SCHED */
9163 static struct cftype cpu_files
[] = {
9164 #ifdef CONFIG_FAIR_GROUP_SCHED
9167 .read_u64
= cpu_shares_read_u64
,
9168 .write_u64
= cpu_shares_write_u64
,
9171 #ifdef CONFIG_RT_GROUP_SCHED
9173 .name
= "rt_runtime_us",
9174 .read_s64
= cpu_rt_runtime_read
,
9175 .write_s64
= cpu_rt_runtime_write
,
9178 .name
= "rt_period_us",
9179 .read_u64
= cpu_rt_period_read_uint
,
9180 .write_u64
= cpu_rt_period_write_uint
,
9185 static int cpu_cgroup_populate(struct cgroup_subsys
*ss
, struct cgroup
*cont
)
9187 return cgroup_add_files(cont
, ss
, cpu_files
, ARRAY_SIZE(cpu_files
));
9190 struct cgroup_subsys cpu_cgroup_subsys
= {
9192 .create
= cpu_cgroup_create
,
9193 .destroy
= cpu_cgroup_destroy
,
9194 .can_attach
= cpu_cgroup_can_attach
,
9195 .attach
= cpu_cgroup_attach
,
9196 .exit
= cpu_cgroup_exit
,
9197 .populate
= cpu_cgroup_populate
,
9198 .subsys_id
= cpu_cgroup_subsys_id
,
9202 #endif /* CONFIG_CGROUP_SCHED */
9204 #ifdef CONFIG_CGROUP_CPUACCT
9207 * CPU accounting code for task groups.
9209 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
9210 * (balbir@in.ibm.com).
9213 /* track cpu usage of a group of tasks and its child groups */
9215 struct cgroup_subsys_state css
;
9216 /* cpuusage holds pointer to a u64-type object on every cpu */
9217 u64 __percpu
*cpuusage
;
9218 struct percpu_counter cpustat
[CPUACCT_STAT_NSTATS
];
9219 struct cpuacct
*parent
;
9222 struct cgroup_subsys cpuacct_subsys
;
9224 /* return cpu accounting group corresponding to this container */
9225 static inline struct cpuacct
*cgroup_ca(struct cgroup
*cgrp
)
9227 return container_of(cgroup_subsys_state(cgrp
, cpuacct_subsys_id
),
9228 struct cpuacct
, css
);
9231 /* return cpu accounting group to which this task belongs */
9232 static inline struct cpuacct
*task_ca(struct task_struct
*tsk
)
9234 return container_of(task_subsys_state(tsk
, cpuacct_subsys_id
),
9235 struct cpuacct
, css
);
9238 /* create a new cpu accounting group */
9239 static struct cgroup_subsys_state
*cpuacct_create(
9240 struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9242 struct cpuacct
*ca
= kzalloc(sizeof(*ca
), GFP_KERNEL
);
9248 ca
->cpuusage
= alloc_percpu(u64
);
9252 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++)
9253 if (percpu_counter_init(&ca
->cpustat
[i
], 0))
9254 goto out_free_counters
;
9257 ca
->parent
= cgroup_ca(cgrp
->parent
);
9263 percpu_counter_destroy(&ca
->cpustat
[i
]);
9264 free_percpu(ca
->cpuusage
);
9268 return ERR_PTR(-ENOMEM
);
9271 /* destroy an existing cpu accounting group */
9273 cpuacct_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9275 struct cpuacct
*ca
= cgroup_ca(cgrp
);
9278 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++)
9279 percpu_counter_destroy(&ca
->cpustat
[i
]);
9280 free_percpu(ca
->cpuusage
);
9284 static u64
cpuacct_cpuusage_read(struct cpuacct
*ca
, int cpu
)
9286 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
9289 #ifndef CONFIG_64BIT
9291 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
9293 raw_spin_lock_irq(&cpu_rq(cpu
)->lock
);
9295 raw_spin_unlock_irq(&cpu_rq(cpu
)->lock
);
9303 static void cpuacct_cpuusage_write(struct cpuacct
*ca
, int cpu
, u64 val
)
9305 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
9307 #ifndef CONFIG_64BIT
9309 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
9311 raw_spin_lock_irq(&cpu_rq(cpu
)->lock
);
9313 raw_spin_unlock_irq(&cpu_rq(cpu
)->lock
);
9319 /* return total cpu usage (in nanoseconds) of a group */
9320 static u64
cpuusage_read(struct cgroup
*cgrp
, struct cftype
*cft
)
9322 struct cpuacct
*ca
= cgroup_ca(cgrp
);
9323 u64 totalcpuusage
= 0;
9326 for_each_present_cpu(i
)
9327 totalcpuusage
+= cpuacct_cpuusage_read(ca
, i
);
9329 return totalcpuusage
;
9332 static int cpuusage_write(struct cgroup
*cgrp
, struct cftype
*cftype
,
9335 struct cpuacct
*ca
= cgroup_ca(cgrp
);
9344 for_each_present_cpu(i
)
9345 cpuacct_cpuusage_write(ca
, i
, 0);
9351 static int cpuacct_percpu_seq_read(struct cgroup
*cgroup
, struct cftype
*cft
,
9354 struct cpuacct
*ca
= cgroup_ca(cgroup
);
9358 for_each_present_cpu(i
) {
9359 percpu
= cpuacct_cpuusage_read(ca
, i
);
9360 seq_printf(m
, "%llu ", (unsigned long long) percpu
);
9362 seq_printf(m
, "\n");
9366 static const char *cpuacct_stat_desc
[] = {
9367 [CPUACCT_STAT_USER
] = "user",
9368 [CPUACCT_STAT_SYSTEM
] = "system",
9371 static int cpuacct_stats_show(struct cgroup
*cgrp
, struct cftype
*cft
,
9372 struct cgroup_map_cb
*cb
)
9374 struct cpuacct
*ca
= cgroup_ca(cgrp
);
9377 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++) {
9378 s64 val
= percpu_counter_read(&ca
->cpustat
[i
]);
9379 val
= cputime64_to_clock_t(val
);
9380 cb
->fill(cb
, cpuacct_stat_desc
[i
], val
);
9385 static struct cftype files
[] = {
9388 .read_u64
= cpuusage_read
,
9389 .write_u64
= cpuusage_write
,
9392 .name
= "usage_percpu",
9393 .read_seq_string
= cpuacct_percpu_seq_read
,
9397 .read_map
= cpuacct_stats_show
,
9401 static int cpuacct_populate(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9403 return cgroup_add_files(cgrp
, ss
, files
, ARRAY_SIZE(files
));
9407 * charge this task's execution time to its accounting group.
9409 * called with rq->lock held.
9411 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
)
9416 if (unlikely(!cpuacct_subsys
.active
))
9419 cpu
= task_cpu(tsk
);
9425 for (; ca
; ca
= ca
->parent
) {
9426 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
9427 *cpuusage
+= cputime
;
9434 * When CONFIG_VIRT_CPU_ACCOUNTING is enabled one jiffy can be very large
9435 * in cputime_t units. As a result, cpuacct_update_stats calls
9436 * percpu_counter_add with values large enough to always overflow the
9437 * per cpu batch limit causing bad SMP scalability.
9439 * To fix this we scale percpu_counter_batch by cputime_one_jiffy so we
9440 * batch the same amount of time with CONFIG_VIRT_CPU_ACCOUNTING disabled
9441 * and enabled. We cap it at INT_MAX which is the largest allowed batch value.
9444 #define CPUACCT_BATCH \
9445 min_t(long, percpu_counter_batch * cputime_one_jiffy, INT_MAX)
9447 #define CPUACCT_BATCH 0
9451 * Charge the system/user time to the task's accounting group.
9453 static void cpuacct_update_stats(struct task_struct
*tsk
,
9454 enum cpuacct_stat_index idx
, cputime_t val
)
9457 int batch
= CPUACCT_BATCH
;
9459 if (unlikely(!cpuacct_subsys
.active
))
9466 __percpu_counter_add(&ca
->cpustat
[idx
], val
, batch
);
9472 struct cgroup_subsys cpuacct_subsys
= {
9474 .create
= cpuacct_create
,
9475 .destroy
= cpuacct_destroy
,
9476 .populate
= cpuacct_populate
,
9477 .subsys_id
= cpuacct_subsys_id
,
9479 #endif /* CONFIG_CGROUP_CPUACCT */