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>
78 #ifdef CONFIG_PARAVIRT
79 #include <asm/paravirt.h>
82 #include "sched_cpupri.h"
83 #include "workqueue_sched.h"
84 #include "sched_autogroup.h"
86 #define CREATE_TRACE_POINTS
87 #include <trace/events/sched.h>
90 * Convert user-nice values [ -20 ... 0 ... 19 ]
91 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
94 #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
95 #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
96 #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
99 * 'User priority' is the nice value converted to something we
100 * can work with better when scaling various scheduler parameters,
101 * it's a [ 0 ... 39 ] range.
103 #define USER_PRIO(p) ((p)-MAX_RT_PRIO)
104 #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
105 #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
108 * Helpers for converting nanosecond timing to jiffy resolution
110 #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
112 #define NICE_0_LOAD SCHED_LOAD_SCALE
113 #define NICE_0_SHIFT SCHED_LOAD_SHIFT
116 * These are the 'tuning knobs' of the scheduler:
118 * default timeslice is 100 msecs (used only for SCHED_RR tasks).
119 * Timeslices get refilled after they expire.
121 #define DEF_TIMESLICE (100 * HZ / 1000)
124 * single value that denotes runtime == period, ie unlimited time.
126 #define RUNTIME_INF ((u64)~0ULL)
128 static inline int rt_policy(int policy
)
130 if (policy
== SCHED_FIFO
|| policy
== SCHED_RR
)
135 static inline int task_has_rt_policy(struct task_struct
*p
)
137 return rt_policy(p
->policy
);
141 * This is the priority-queue data structure of the RT scheduling class:
143 struct rt_prio_array
{
144 DECLARE_BITMAP(bitmap
, MAX_RT_PRIO
+1); /* include 1 bit for delimiter */
145 struct list_head queue
[MAX_RT_PRIO
];
148 struct rt_bandwidth
{
149 /* nests inside the rq lock: */
150 raw_spinlock_t rt_runtime_lock
;
153 struct hrtimer rt_period_timer
;
156 static struct rt_bandwidth def_rt_bandwidth
;
158 static int do_sched_rt_period_timer(struct rt_bandwidth
*rt_b
, int overrun
);
160 static enum hrtimer_restart
sched_rt_period_timer(struct hrtimer
*timer
)
162 struct rt_bandwidth
*rt_b
=
163 container_of(timer
, struct rt_bandwidth
, rt_period_timer
);
169 now
= hrtimer_cb_get_time(timer
);
170 overrun
= hrtimer_forward(timer
, now
, rt_b
->rt_period
);
175 idle
= do_sched_rt_period_timer(rt_b
, overrun
);
178 return idle
? HRTIMER_NORESTART
: HRTIMER_RESTART
;
182 void init_rt_bandwidth(struct rt_bandwidth
*rt_b
, u64 period
, u64 runtime
)
184 rt_b
->rt_period
= ns_to_ktime(period
);
185 rt_b
->rt_runtime
= runtime
;
187 raw_spin_lock_init(&rt_b
->rt_runtime_lock
);
189 hrtimer_init(&rt_b
->rt_period_timer
,
190 CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
191 rt_b
->rt_period_timer
.function
= sched_rt_period_timer
;
194 static inline int rt_bandwidth_enabled(void)
196 return sysctl_sched_rt_runtime
>= 0;
199 static void start_rt_bandwidth(struct rt_bandwidth
*rt_b
)
203 if (!rt_bandwidth_enabled() || rt_b
->rt_runtime
== RUNTIME_INF
)
206 if (hrtimer_active(&rt_b
->rt_period_timer
))
209 raw_spin_lock(&rt_b
->rt_runtime_lock
);
214 if (hrtimer_active(&rt_b
->rt_period_timer
))
217 now
= hrtimer_cb_get_time(&rt_b
->rt_period_timer
);
218 hrtimer_forward(&rt_b
->rt_period_timer
, now
, rt_b
->rt_period
);
220 soft
= hrtimer_get_softexpires(&rt_b
->rt_period_timer
);
221 hard
= hrtimer_get_expires(&rt_b
->rt_period_timer
);
222 delta
= ktime_to_ns(ktime_sub(hard
, soft
));
223 __hrtimer_start_range_ns(&rt_b
->rt_period_timer
, soft
, delta
,
224 HRTIMER_MODE_ABS_PINNED
, 0);
226 raw_spin_unlock(&rt_b
->rt_runtime_lock
);
229 #ifdef CONFIG_RT_GROUP_SCHED
230 static void destroy_rt_bandwidth(struct rt_bandwidth
*rt_b
)
232 hrtimer_cancel(&rt_b
->rt_period_timer
);
237 * sched_domains_mutex serializes calls to init_sched_domains,
238 * detach_destroy_domains and partition_sched_domains.
240 static DEFINE_MUTEX(sched_domains_mutex
);
242 #ifdef CONFIG_CGROUP_SCHED
244 #include <linux/cgroup.h>
248 static LIST_HEAD(task_groups
);
250 /* task group related information */
252 struct cgroup_subsys_state css
;
254 #ifdef CONFIG_FAIR_GROUP_SCHED
255 /* schedulable entities of this group on each cpu */
256 struct sched_entity
**se
;
257 /* runqueue "owned" by this group on each cpu */
258 struct cfs_rq
**cfs_rq
;
259 unsigned long shares
;
261 atomic_t load_weight
;
264 #ifdef CONFIG_RT_GROUP_SCHED
265 struct sched_rt_entity
**rt_se
;
266 struct rt_rq
**rt_rq
;
268 struct rt_bandwidth rt_bandwidth
;
272 struct list_head list
;
274 struct task_group
*parent
;
275 struct list_head siblings
;
276 struct list_head children
;
278 #ifdef CONFIG_SCHED_AUTOGROUP
279 struct autogroup
*autogroup
;
283 /* task_group_lock serializes the addition/removal of task groups */
284 static DEFINE_SPINLOCK(task_group_lock
);
286 #ifdef CONFIG_FAIR_GROUP_SCHED
288 # define ROOT_TASK_GROUP_LOAD NICE_0_LOAD
291 * A weight of 0 or 1 can cause arithmetics problems.
292 * A weight of a cfs_rq is the sum of weights of which entities
293 * are queued on this cfs_rq, so a weight of a entity should not be
294 * too large, so as the shares value of a task group.
295 * (The default weight is 1024 - so there's no practical
296 * limitation from this.)
298 #define MIN_SHARES (1UL << 1)
299 #define MAX_SHARES (1UL << 18)
301 static int root_task_group_load
= ROOT_TASK_GROUP_LOAD
;
304 /* Default task group.
305 * Every task in system belong to this group at bootup.
307 struct task_group root_task_group
;
309 #endif /* CONFIG_CGROUP_SCHED */
311 /* CFS-related fields in a runqueue */
313 struct load_weight load
;
314 unsigned long nr_running
;
319 u64 min_vruntime_copy
;
322 struct rb_root tasks_timeline
;
323 struct rb_node
*rb_leftmost
;
325 struct list_head tasks
;
326 struct list_head
*balance_iterator
;
329 * 'curr' points to currently running entity on this cfs_rq.
330 * It is set to NULL otherwise (i.e when none are currently running).
332 struct sched_entity
*curr
, *next
, *last
, *skip
;
334 #ifdef CONFIG_SCHED_DEBUG
335 unsigned int nr_spread_over
;
338 #ifdef CONFIG_FAIR_GROUP_SCHED
339 struct rq
*rq
; /* cpu runqueue to which this cfs_rq is attached */
342 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
343 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
344 * (like users, containers etc.)
346 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
347 * list is used during load balance.
350 struct list_head leaf_cfs_rq_list
;
351 struct task_group
*tg
; /* group that "owns" this runqueue */
355 * the part of load.weight contributed by tasks
357 unsigned long task_weight
;
360 * h_load = weight * f(tg)
362 * Where f(tg) is the recursive weight fraction assigned to
365 unsigned long h_load
;
368 * Maintaining per-cpu shares distribution for group scheduling
370 * load_stamp is the last time we updated the load average
371 * load_last is the last time we updated the load average and saw load
372 * load_unacc_exec_time is currently unaccounted execution time
376 u64 load_stamp
, load_last
, load_unacc_exec_time
;
378 unsigned long load_contribution
;
383 /* Real-Time classes' related field in a runqueue: */
385 struct rt_prio_array active
;
386 unsigned long rt_nr_running
;
387 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
389 int curr
; /* highest queued rt task prio */
391 int next
; /* next highest */
396 unsigned long rt_nr_migratory
;
397 unsigned long rt_nr_total
;
399 struct plist_head pushable_tasks
;
404 /* Nests inside the rq lock: */
405 raw_spinlock_t rt_runtime_lock
;
407 #ifdef CONFIG_RT_GROUP_SCHED
408 unsigned long rt_nr_boosted
;
411 struct list_head leaf_rt_rq_list
;
412 struct task_group
*tg
;
419 * We add the notion of a root-domain which will be used to define per-domain
420 * variables. Each exclusive cpuset essentially defines an island domain by
421 * fully partitioning the member cpus from any other cpuset. Whenever a new
422 * exclusive cpuset is created, we also create and attach a new root-domain
431 cpumask_var_t online
;
434 * The "RT overload" flag: it gets set if a CPU has more than
435 * one runnable RT task.
437 cpumask_var_t rto_mask
;
438 struct cpupri cpupri
;
442 * By default the system creates a single root-domain with all cpus as
443 * members (mimicking the global state we have today).
445 static struct root_domain def_root_domain
;
447 #endif /* CONFIG_SMP */
450 * This is the main, per-CPU runqueue data structure.
452 * Locking rule: those places that want to lock multiple runqueues
453 * (such as the load balancing or the thread migration code), lock
454 * acquire operations must be ordered by ascending &runqueue.
461 * nr_running and cpu_load should be in the same cacheline because
462 * remote CPUs use both these fields when doing load calculation.
464 unsigned long nr_running
;
465 #define CPU_LOAD_IDX_MAX 5
466 unsigned long cpu_load
[CPU_LOAD_IDX_MAX
];
467 unsigned long last_load_update_tick
;
470 unsigned char nohz_balance_kick
;
472 int skip_clock_update
;
474 /* capture load from *all* tasks on this cpu: */
475 struct load_weight load
;
476 unsigned long nr_load_updates
;
482 #ifdef CONFIG_FAIR_GROUP_SCHED
483 /* list of leaf cfs_rq on this cpu: */
484 struct list_head leaf_cfs_rq_list
;
486 #ifdef CONFIG_RT_GROUP_SCHED
487 struct list_head leaf_rt_rq_list
;
491 * This is part of a global counter where only the total sum
492 * over all CPUs matters. A task can increase this counter on
493 * one CPU and if it got migrated afterwards it may decrease
494 * it on another CPU. Always updated under the runqueue lock:
496 unsigned long nr_uninterruptible
;
498 struct task_struct
*curr
, *idle
, *stop
;
499 unsigned long next_balance
;
500 struct mm_struct
*prev_mm
;
508 struct root_domain
*rd
;
509 struct sched_domain
*sd
;
511 unsigned long cpu_power
;
513 unsigned char idle_at_tick
;
514 /* For active balancing */
518 struct cpu_stop_work active_balance_work
;
519 /* cpu of this runqueue: */
523 unsigned long avg_load_per_task
;
531 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
534 #ifdef CONFIG_PARAVIRT
537 #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
538 u64 prev_steal_time_rq
;
541 /* calc_load related fields */
542 unsigned long calc_load_update
;
543 long calc_load_active
;
545 #ifdef CONFIG_SCHED_HRTICK
547 int hrtick_csd_pending
;
548 struct call_single_data hrtick_csd
;
550 struct hrtimer hrtick_timer
;
553 #ifdef CONFIG_SCHEDSTATS
555 struct sched_info rq_sched_info
;
556 unsigned long long rq_cpu_time
;
557 /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
559 /* sys_sched_yield() stats */
560 unsigned int yld_count
;
562 /* schedule() stats */
563 unsigned int sched_switch
;
564 unsigned int sched_count
;
565 unsigned int sched_goidle
;
567 /* try_to_wake_up() stats */
568 unsigned int ttwu_count
;
569 unsigned int ttwu_local
;
573 struct task_struct
*wake_list
;
577 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
580 static void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int flags
);
582 static inline int cpu_of(struct rq
*rq
)
591 #define rcu_dereference_check_sched_domain(p) \
592 rcu_dereference_check((p), \
593 lockdep_is_held(&sched_domains_mutex))
596 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
597 * See detach_destroy_domains: synchronize_sched for details.
599 * The domain tree of any CPU may only be accessed from within
600 * preempt-disabled sections.
602 #define for_each_domain(cpu, __sd) \
603 for (__sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
605 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
606 #define this_rq() (&__get_cpu_var(runqueues))
607 #define task_rq(p) cpu_rq(task_cpu(p))
608 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
609 #define raw_rq() (&__raw_get_cpu_var(runqueues))
611 #ifdef CONFIG_CGROUP_SCHED
614 * Return the group to which this tasks belongs.
616 * We use task_subsys_state_check() and extend the RCU verification with
617 * pi->lock and rq->lock because cpu_cgroup_attach() holds those locks for each
618 * task it moves into the cgroup. Therefore by holding either of those locks,
619 * we pin the task to the current cgroup.
621 static inline struct task_group
*task_group(struct task_struct
*p
)
623 struct task_group
*tg
;
624 struct cgroup_subsys_state
*css
;
626 css
= task_subsys_state_check(p
, cpu_cgroup_subsys_id
,
627 lockdep_is_held(&p
->pi_lock
) ||
628 lockdep_is_held(&task_rq(p
)->lock
));
629 tg
= container_of(css
, struct task_group
, css
);
631 return autogroup_task_group(p
, tg
);
634 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
635 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
)
637 #ifdef CONFIG_FAIR_GROUP_SCHED
638 p
->se
.cfs_rq
= task_group(p
)->cfs_rq
[cpu
];
639 p
->se
.parent
= task_group(p
)->se
[cpu
];
642 #ifdef CONFIG_RT_GROUP_SCHED
643 p
->rt
.rt_rq
= task_group(p
)->rt_rq
[cpu
];
644 p
->rt
.parent
= task_group(p
)->rt_se
[cpu
];
648 #else /* CONFIG_CGROUP_SCHED */
650 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
) { }
651 static inline struct task_group
*task_group(struct task_struct
*p
)
656 #endif /* CONFIG_CGROUP_SCHED */
658 static void update_rq_clock_task(struct rq
*rq
, s64 delta
);
660 static void update_rq_clock(struct rq
*rq
)
664 if (rq
->skip_clock_update
> 0)
667 delta
= sched_clock_cpu(cpu_of(rq
)) - rq
->clock
;
669 update_rq_clock_task(rq
, delta
);
673 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
675 #ifdef CONFIG_SCHED_DEBUG
676 # define const_debug __read_mostly
678 # define const_debug static const
682 * runqueue_is_locked - Returns true if the current cpu runqueue is locked
683 * @cpu: the processor in question.
685 * This interface allows printk to be called with the runqueue lock
686 * held and know whether or not it is OK to wake up the klogd.
688 int runqueue_is_locked(int cpu
)
690 return raw_spin_is_locked(&cpu_rq(cpu
)->lock
);
694 * Debugging: various feature bits
697 #define SCHED_FEAT(name, enabled) \
698 __SCHED_FEAT_##name ,
701 #include "sched_features.h"
706 #define SCHED_FEAT(name, enabled) \
707 (1UL << __SCHED_FEAT_##name) * enabled |
709 const_debug
unsigned int sysctl_sched_features
=
710 #include "sched_features.h"
715 #ifdef CONFIG_SCHED_DEBUG
716 #define SCHED_FEAT(name, enabled) \
719 static __read_mostly
char *sched_feat_names
[] = {
720 #include "sched_features.h"
726 static int sched_feat_show(struct seq_file
*m
, void *v
)
730 for (i
= 0; sched_feat_names
[i
]; i
++) {
731 if (!(sysctl_sched_features
& (1UL << i
)))
733 seq_printf(m
, "%s ", sched_feat_names
[i
]);
741 sched_feat_write(struct file
*filp
, const char __user
*ubuf
,
742 size_t cnt
, loff_t
*ppos
)
752 if (copy_from_user(&buf
, ubuf
, cnt
))
758 if (strncmp(cmp
, "NO_", 3) == 0) {
763 for (i
= 0; sched_feat_names
[i
]; i
++) {
764 if (strcmp(cmp
, sched_feat_names
[i
]) == 0) {
766 sysctl_sched_features
&= ~(1UL << i
);
768 sysctl_sched_features
|= (1UL << i
);
773 if (!sched_feat_names
[i
])
781 static int sched_feat_open(struct inode
*inode
, struct file
*filp
)
783 return single_open(filp
, sched_feat_show
, NULL
);
786 static const struct file_operations sched_feat_fops
= {
787 .open
= sched_feat_open
,
788 .write
= sched_feat_write
,
791 .release
= single_release
,
794 static __init
int sched_init_debug(void)
796 debugfs_create_file("sched_features", 0644, NULL
, NULL
,
801 late_initcall(sched_init_debug
);
805 #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
808 * Number of tasks to iterate in a single balance run.
809 * Limited because this is done with IRQs disabled.
811 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
814 * period over which we average the RT time consumption, measured
819 const_debug
unsigned int sysctl_sched_time_avg
= MSEC_PER_SEC
;
822 * period over which we measure -rt task cpu usage in us.
825 unsigned int sysctl_sched_rt_period
= 1000000;
827 static __read_mostly
int scheduler_running
;
830 * part of the period that we allow rt tasks to run in us.
833 int sysctl_sched_rt_runtime
= 950000;
835 static inline u64
global_rt_period(void)
837 return (u64
)sysctl_sched_rt_period
* NSEC_PER_USEC
;
840 static inline u64
global_rt_runtime(void)
842 if (sysctl_sched_rt_runtime
< 0)
845 return (u64
)sysctl_sched_rt_runtime
* NSEC_PER_USEC
;
848 #ifndef prepare_arch_switch
849 # define prepare_arch_switch(next) do { } while (0)
851 #ifndef finish_arch_switch
852 # define finish_arch_switch(prev) do { } while (0)
855 static inline int task_current(struct rq
*rq
, struct task_struct
*p
)
857 return rq
->curr
== p
;
860 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
865 return task_current(rq
, p
);
869 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
870 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
874 * We can optimise this out completely for !SMP, because the
875 * SMP rebalancing from interrupt is the only thing that cares
882 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
886 * After ->on_cpu is cleared, the task can be moved to a different CPU.
887 * We must ensure this doesn't happen until the switch is completely
893 #ifdef CONFIG_DEBUG_SPINLOCK
894 /* this is a valid case when another task releases the spinlock */
895 rq
->lock
.owner
= current
;
898 * If we are tracking spinlock dependencies then we have to
899 * fix up the runqueue lock - which gets 'carried over' from
902 spin_acquire(&rq
->lock
.dep_map
, 0, 0, _THIS_IP_
);
904 raw_spin_unlock_irq(&rq
->lock
);
907 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
908 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
912 * We can optimise this out completely for !SMP, because the
913 * SMP rebalancing from interrupt is the only thing that cares
918 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
919 raw_spin_unlock_irq(&rq
->lock
);
921 raw_spin_unlock(&rq
->lock
);
925 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
929 * After ->on_cpu is cleared, the task can be moved to a different CPU.
930 * We must ensure this doesn't happen until the switch is completely
936 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
940 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
943 * __task_rq_lock - lock the rq @p resides on.
945 static inline struct rq
*__task_rq_lock(struct task_struct
*p
)
950 lockdep_assert_held(&p
->pi_lock
);
954 raw_spin_lock(&rq
->lock
);
955 if (likely(rq
== task_rq(p
)))
957 raw_spin_unlock(&rq
->lock
);
962 * task_rq_lock - lock p->pi_lock and lock the rq @p resides on.
964 static struct rq
*task_rq_lock(struct task_struct
*p
, unsigned long *flags
)
965 __acquires(p
->pi_lock
)
971 raw_spin_lock_irqsave(&p
->pi_lock
, *flags
);
973 raw_spin_lock(&rq
->lock
);
974 if (likely(rq
== task_rq(p
)))
976 raw_spin_unlock(&rq
->lock
);
977 raw_spin_unlock_irqrestore(&p
->pi_lock
, *flags
);
981 static void __task_rq_unlock(struct rq
*rq
)
984 raw_spin_unlock(&rq
->lock
);
988 task_rq_unlock(struct rq
*rq
, struct task_struct
*p
, unsigned long *flags
)
990 __releases(p
->pi_lock
)
992 raw_spin_unlock(&rq
->lock
);
993 raw_spin_unlock_irqrestore(&p
->pi_lock
, *flags
);
997 * this_rq_lock - lock this runqueue and disable interrupts.
999 static struct rq
*this_rq_lock(void)
1000 __acquires(rq
->lock
)
1004 local_irq_disable();
1006 raw_spin_lock(&rq
->lock
);
1011 #ifdef CONFIG_SCHED_HRTICK
1013 * Use HR-timers to deliver accurate preemption points.
1015 * Its all a bit involved since we cannot program an hrt while holding the
1016 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
1019 * When we get rescheduled we reprogram the hrtick_timer outside of the
1025 * - enabled by features
1026 * - hrtimer is actually high res
1028 static inline int hrtick_enabled(struct rq
*rq
)
1030 if (!sched_feat(HRTICK
))
1032 if (!cpu_active(cpu_of(rq
)))
1034 return hrtimer_is_hres_active(&rq
->hrtick_timer
);
1037 static void hrtick_clear(struct rq
*rq
)
1039 if (hrtimer_active(&rq
->hrtick_timer
))
1040 hrtimer_cancel(&rq
->hrtick_timer
);
1044 * High-resolution timer tick.
1045 * Runs from hardirq context with interrupts disabled.
1047 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
1049 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
1051 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1053 raw_spin_lock(&rq
->lock
);
1054 update_rq_clock(rq
);
1055 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
1056 raw_spin_unlock(&rq
->lock
);
1058 return HRTIMER_NORESTART
;
1063 * called from hardirq (IPI) context
1065 static void __hrtick_start(void *arg
)
1067 struct rq
*rq
= arg
;
1069 raw_spin_lock(&rq
->lock
);
1070 hrtimer_restart(&rq
->hrtick_timer
);
1071 rq
->hrtick_csd_pending
= 0;
1072 raw_spin_unlock(&rq
->lock
);
1076 * Called to set the hrtick timer state.
1078 * called with rq->lock held and irqs disabled
1080 static void hrtick_start(struct rq
*rq
, u64 delay
)
1082 struct hrtimer
*timer
= &rq
->hrtick_timer
;
1083 ktime_t time
= ktime_add_ns(timer
->base
->get_time(), delay
);
1085 hrtimer_set_expires(timer
, time
);
1087 if (rq
== this_rq()) {
1088 hrtimer_restart(timer
);
1089 } else if (!rq
->hrtick_csd_pending
) {
1090 __smp_call_function_single(cpu_of(rq
), &rq
->hrtick_csd
, 0);
1091 rq
->hrtick_csd_pending
= 1;
1096 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
1098 int cpu
= (int)(long)hcpu
;
1101 case CPU_UP_CANCELED
:
1102 case CPU_UP_CANCELED_FROZEN
:
1103 case CPU_DOWN_PREPARE
:
1104 case CPU_DOWN_PREPARE_FROZEN
:
1106 case CPU_DEAD_FROZEN
:
1107 hrtick_clear(cpu_rq(cpu
));
1114 static __init
void init_hrtick(void)
1116 hotcpu_notifier(hotplug_hrtick
, 0);
1120 * Called to set the hrtick timer state.
1122 * called with rq->lock held and irqs disabled
1124 static void hrtick_start(struct rq
*rq
, u64 delay
)
1126 __hrtimer_start_range_ns(&rq
->hrtick_timer
, ns_to_ktime(delay
), 0,
1127 HRTIMER_MODE_REL_PINNED
, 0);
1130 static inline void init_hrtick(void)
1133 #endif /* CONFIG_SMP */
1135 static void init_rq_hrtick(struct rq
*rq
)
1138 rq
->hrtick_csd_pending
= 0;
1140 rq
->hrtick_csd
.flags
= 0;
1141 rq
->hrtick_csd
.func
= __hrtick_start
;
1142 rq
->hrtick_csd
.info
= rq
;
1145 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1146 rq
->hrtick_timer
.function
= hrtick
;
1148 #else /* CONFIG_SCHED_HRTICK */
1149 static inline void hrtick_clear(struct rq
*rq
)
1153 static inline void init_rq_hrtick(struct rq
*rq
)
1157 static inline void init_hrtick(void)
1160 #endif /* CONFIG_SCHED_HRTICK */
1163 * resched_task - mark a task 'to be rescheduled now'.
1165 * On UP this means the setting of the need_resched flag, on SMP it
1166 * might also involve a cross-CPU call to trigger the scheduler on
1171 #ifndef tsk_is_polling
1172 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1175 static void resched_task(struct task_struct
*p
)
1179 assert_raw_spin_locked(&task_rq(p
)->lock
);
1181 if (test_tsk_need_resched(p
))
1184 set_tsk_need_resched(p
);
1187 if (cpu
== smp_processor_id())
1190 /* NEED_RESCHED must be visible before we test polling */
1192 if (!tsk_is_polling(p
))
1193 smp_send_reschedule(cpu
);
1196 static void resched_cpu(int cpu
)
1198 struct rq
*rq
= cpu_rq(cpu
);
1199 unsigned long flags
;
1201 if (!raw_spin_trylock_irqsave(&rq
->lock
, flags
))
1203 resched_task(cpu_curr(cpu
));
1204 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
1209 * In the semi idle case, use the nearest busy cpu for migrating timers
1210 * from an idle cpu. This is good for power-savings.
1212 * We don't do similar optimization for completely idle system, as
1213 * selecting an idle cpu will add more delays to the timers than intended
1214 * (as that cpu's timer base may not be uptodate wrt jiffies etc).
1216 int get_nohz_timer_target(void)
1218 int cpu
= smp_processor_id();
1220 struct sched_domain
*sd
;
1223 for_each_domain(cpu
, sd
) {
1224 for_each_cpu(i
, sched_domain_span(sd
)) {
1236 * When add_timer_on() enqueues a timer into the timer wheel of an
1237 * idle CPU then this timer might expire before the next timer event
1238 * which is scheduled to wake up that CPU. In case of a completely
1239 * idle system the next event might even be infinite time into the
1240 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1241 * leaves the inner idle loop so the newly added timer is taken into
1242 * account when the CPU goes back to idle and evaluates the timer
1243 * wheel for the next timer event.
1245 void wake_up_idle_cpu(int cpu
)
1247 struct rq
*rq
= cpu_rq(cpu
);
1249 if (cpu
== smp_processor_id())
1253 * This is safe, as this function is called with the timer
1254 * wheel base lock of (cpu) held. When the CPU is on the way
1255 * to idle and has not yet set rq->curr to idle then it will
1256 * be serialized on the timer wheel base lock and take the new
1257 * timer into account automatically.
1259 if (rq
->curr
!= rq
->idle
)
1263 * We can set TIF_RESCHED on the idle task of the other CPU
1264 * lockless. The worst case is that the other CPU runs the
1265 * idle task through an additional NOOP schedule()
1267 set_tsk_need_resched(rq
->idle
);
1269 /* NEED_RESCHED must be visible before we test polling */
1271 if (!tsk_is_polling(rq
->idle
))
1272 smp_send_reschedule(cpu
);
1275 #endif /* CONFIG_NO_HZ */
1277 static u64
sched_avg_period(void)
1279 return (u64
)sysctl_sched_time_avg
* NSEC_PER_MSEC
/ 2;
1282 static void sched_avg_update(struct rq
*rq
)
1284 s64 period
= sched_avg_period();
1286 while ((s64
)(rq
->clock
- rq
->age_stamp
) > period
) {
1288 * Inline assembly required to prevent the compiler
1289 * optimising this loop into a divmod call.
1290 * See __iter_div_u64_rem() for another example of this.
1292 asm("" : "+rm" (rq
->age_stamp
));
1293 rq
->age_stamp
+= period
;
1298 static void sched_rt_avg_update(struct rq
*rq
, u64 rt_delta
)
1300 rq
->rt_avg
+= rt_delta
;
1301 sched_avg_update(rq
);
1304 #else /* !CONFIG_SMP */
1305 static void resched_task(struct task_struct
*p
)
1307 assert_raw_spin_locked(&task_rq(p
)->lock
);
1308 set_tsk_need_resched(p
);
1311 static void sched_rt_avg_update(struct rq
*rq
, u64 rt_delta
)
1315 static void sched_avg_update(struct rq
*rq
)
1318 #endif /* CONFIG_SMP */
1320 #if BITS_PER_LONG == 32
1321 # define WMULT_CONST (~0UL)
1323 # define WMULT_CONST (1UL << 32)
1326 #define WMULT_SHIFT 32
1329 * Shift right and round:
1331 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1334 * delta *= weight / lw
1336 static unsigned long
1337 calc_delta_mine(unsigned long delta_exec
, unsigned long weight
,
1338 struct load_weight
*lw
)
1343 * weight can be less than 2^SCHED_LOAD_RESOLUTION for task group sched
1344 * entities since MIN_SHARES = 2. Treat weight as 1 if less than
1345 * 2^SCHED_LOAD_RESOLUTION.
1347 if (likely(weight
> (1UL << SCHED_LOAD_RESOLUTION
)))
1348 tmp
= (u64
)delta_exec
* scale_load_down(weight
);
1350 tmp
= (u64
)delta_exec
;
1352 if (!lw
->inv_weight
) {
1353 unsigned long w
= scale_load_down(lw
->weight
);
1355 if (BITS_PER_LONG
> 32 && unlikely(w
>= WMULT_CONST
))
1357 else if (unlikely(!w
))
1358 lw
->inv_weight
= WMULT_CONST
;
1360 lw
->inv_weight
= WMULT_CONST
/ w
;
1364 * Check whether we'd overflow the 64-bit multiplication:
1366 if (unlikely(tmp
> WMULT_CONST
))
1367 tmp
= SRR(SRR(tmp
, WMULT_SHIFT
/2) * lw
->inv_weight
,
1370 tmp
= SRR(tmp
* lw
->inv_weight
, WMULT_SHIFT
);
1372 return (unsigned long)min(tmp
, (u64
)(unsigned long)LONG_MAX
);
1375 static inline void update_load_add(struct load_weight
*lw
, unsigned long inc
)
1381 static inline void update_load_sub(struct load_weight
*lw
, unsigned long dec
)
1387 static inline void update_load_set(struct load_weight
*lw
, unsigned long w
)
1394 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1395 * of tasks with abnormal "nice" values across CPUs the contribution that
1396 * each task makes to its run queue's load is weighted according to its
1397 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1398 * scaled version of the new time slice allocation that they receive on time
1402 #define WEIGHT_IDLEPRIO 3
1403 #define WMULT_IDLEPRIO 1431655765
1406 * Nice levels are multiplicative, with a gentle 10% change for every
1407 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1408 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1409 * that remained on nice 0.
1411 * The "10% effect" is relative and cumulative: from _any_ nice level,
1412 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1413 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1414 * If a task goes up by ~10% and another task goes down by ~10% then
1415 * the relative distance between them is ~25%.)
1417 static const int prio_to_weight
[40] = {
1418 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1419 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1420 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1421 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1422 /* 0 */ 1024, 820, 655, 526, 423,
1423 /* 5 */ 335, 272, 215, 172, 137,
1424 /* 10 */ 110, 87, 70, 56, 45,
1425 /* 15 */ 36, 29, 23, 18, 15,
1429 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1431 * In cases where the weight does not change often, we can use the
1432 * precalculated inverse to speed up arithmetics by turning divisions
1433 * into multiplications:
1435 static const u32 prio_to_wmult
[40] = {
1436 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1437 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1438 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1439 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1440 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1441 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1442 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1443 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1446 /* Time spent by the tasks of the cpu accounting group executing in ... */
1447 enum cpuacct_stat_index
{
1448 CPUACCT_STAT_USER
, /* ... user mode */
1449 CPUACCT_STAT_SYSTEM
, /* ... kernel mode */
1451 CPUACCT_STAT_NSTATS
,
1454 #ifdef CONFIG_CGROUP_CPUACCT
1455 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
);
1456 static void cpuacct_update_stats(struct task_struct
*tsk
,
1457 enum cpuacct_stat_index idx
, cputime_t val
);
1459 static inline void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
) {}
1460 static inline void cpuacct_update_stats(struct task_struct
*tsk
,
1461 enum cpuacct_stat_index idx
, cputime_t val
) {}
1464 static inline void inc_cpu_load(struct rq
*rq
, unsigned long load
)
1466 update_load_add(&rq
->load
, load
);
1469 static inline void dec_cpu_load(struct rq
*rq
, unsigned long load
)
1471 update_load_sub(&rq
->load
, load
);
1474 #if (defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)) || defined(CONFIG_RT_GROUP_SCHED)
1475 typedef int (*tg_visitor
)(struct task_group
*, void *);
1478 * Iterate the full tree, calling @down when first entering a node and @up when
1479 * leaving it for the final time.
1481 static int walk_tg_tree(tg_visitor down
, tg_visitor up
, void *data
)
1483 struct task_group
*parent
, *child
;
1487 parent
= &root_task_group
;
1489 ret
= (*down
)(parent
, data
);
1492 list_for_each_entry_rcu(child
, &parent
->children
, siblings
) {
1499 ret
= (*up
)(parent
, data
);
1504 parent
= parent
->parent
;
1513 static int tg_nop(struct task_group
*tg
, void *data
)
1520 /* Used instead of source_load when we know the type == 0 */
1521 static unsigned long weighted_cpuload(const int cpu
)
1523 return cpu_rq(cpu
)->load
.weight
;
1527 * Return a low guess at the load of a migration-source cpu weighted
1528 * according to the scheduling class and "nice" value.
1530 * We want to under-estimate the load of migration sources, to
1531 * balance conservatively.
1533 static unsigned long source_load(int cpu
, int type
)
1535 struct rq
*rq
= cpu_rq(cpu
);
1536 unsigned long total
= weighted_cpuload(cpu
);
1538 if (type
== 0 || !sched_feat(LB_BIAS
))
1541 return min(rq
->cpu_load
[type
-1], total
);
1545 * Return a high guess at the load of a migration-target cpu weighted
1546 * according to the scheduling class and "nice" value.
1548 static unsigned long target_load(int cpu
, int type
)
1550 struct rq
*rq
= cpu_rq(cpu
);
1551 unsigned long total
= weighted_cpuload(cpu
);
1553 if (type
== 0 || !sched_feat(LB_BIAS
))
1556 return max(rq
->cpu_load
[type
-1], total
);
1559 static unsigned long power_of(int cpu
)
1561 return cpu_rq(cpu
)->cpu_power
;
1564 static int task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
);
1566 static unsigned long cpu_avg_load_per_task(int cpu
)
1568 struct rq
*rq
= cpu_rq(cpu
);
1569 unsigned long nr_running
= ACCESS_ONCE(rq
->nr_running
);
1572 rq
->avg_load_per_task
= rq
->load
.weight
/ nr_running
;
1574 rq
->avg_load_per_task
= 0;
1576 return rq
->avg_load_per_task
;
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
)
1770 int prio
= p
->static_prio
- MAX_RT_PRIO
;
1771 struct load_weight
*load
= &p
->se
.load
;
1774 * SCHED_IDLE tasks get minimal weight:
1776 if (p
->policy
== SCHED_IDLE
) {
1777 load
->weight
= scale_load(WEIGHT_IDLEPRIO
);
1778 load
->inv_weight
= WMULT_IDLEPRIO
;
1782 load
->weight
= scale_load(prio_to_weight
[prio
]);
1783 load
->inv_weight
= prio_to_wmult
[prio
];
1786 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
1788 update_rq_clock(rq
);
1789 sched_info_queued(p
);
1790 p
->sched_class
->enqueue_task(rq
, p
, flags
);
1793 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
1795 update_rq_clock(rq
);
1796 sched_info_dequeued(p
);
1797 p
->sched_class
->dequeue_task(rq
, p
, flags
);
1801 * activate_task - move a task to the runqueue.
1803 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
1805 if (task_contributes_to_load(p
))
1806 rq
->nr_uninterruptible
--;
1808 enqueue_task(rq
, p
, flags
);
1813 * deactivate_task - remove a task from the runqueue.
1815 static void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
1817 if (task_contributes_to_load(p
))
1818 rq
->nr_uninterruptible
++;
1820 dequeue_task(rq
, p
, flags
);
1824 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
1827 * There are no locks covering percpu hardirq/softirq time.
1828 * They are only modified in account_system_vtime, on corresponding CPU
1829 * with interrupts disabled. So, writes are safe.
1830 * They are read and saved off onto struct rq in update_rq_clock().
1831 * This may result in other CPU reading this CPU's irq time and can
1832 * race with irq/account_system_vtime on this CPU. We would either get old
1833 * or new value with a side effect of accounting a slice of irq time to wrong
1834 * task when irq is in progress while we read rq->clock. That is a worthy
1835 * compromise in place of having locks on each irq in account_system_time.
1837 static DEFINE_PER_CPU(u64
, cpu_hardirq_time
);
1838 static DEFINE_PER_CPU(u64
, cpu_softirq_time
);
1840 static DEFINE_PER_CPU(u64
, irq_start_time
);
1841 static int sched_clock_irqtime
;
1843 void enable_sched_clock_irqtime(void)
1845 sched_clock_irqtime
= 1;
1848 void disable_sched_clock_irqtime(void)
1850 sched_clock_irqtime
= 0;
1853 #ifndef CONFIG_64BIT
1854 static DEFINE_PER_CPU(seqcount_t
, irq_time_seq
);
1856 static inline void irq_time_write_begin(void)
1858 __this_cpu_inc(irq_time_seq
.sequence
);
1862 static inline void irq_time_write_end(void)
1865 __this_cpu_inc(irq_time_seq
.sequence
);
1868 static inline u64
irq_time_read(int cpu
)
1874 seq
= read_seqcount_begin(&per_cpu(irq_time_seq
, cpu
));
1875 irq_time
= per_cpu(cpu_softirq_time
, cpu
) +
1876 per_cpu(cpu_hardirq_time
, cpu
);
1877 } while (read_seqcount_retry(&per_cpu(irq_time_seq
, cpu
), seq
));
1881 #else /* CONFIG_64BIT */
1882 static inline void irq_time_write_begin(void)
1886 static inline void irq_time_write_end(void)
1890 static inline u64
irq_time_read(int cpu
)
1892 return per_cpu(cpu_softirq_time
, cpu
) + per_cpu(cpu_hardirq_time
, cpu
);
1894 #endif /* CONFIG_64BIT */
1897 * Called before incrementing preempt_count on {soft,}irq_enter
1898 * and before decrementing preempt_count on {soft,}irq_exit.
1900 void account_system_vtime(struct task_struct
*curr
)
1902 unsigned long flags
;
1906 if (!sched_clock_irqtime
)
1909 local_irq_save(flags
);
1911 cpu
= smp_processor_id();
1912 delta
= sched_clock_cpu(cpu
) - __this_cpu_read(irq_start_time
);
1913 __this_cpu_add(irq_start_time
, delta
);
1915 irq_time_write_begin();
1917 * We do not account for softirq time from ksoftirqd here.
1918 * We want to continue accounting softirq time to ksoftirqd thread
1919 * in that case, so as not to confuse scheduler with a special task
1920 * that do not consume any time, but still wants to run.
1922 if (hardirq_count())
1923 __this_cpu_add(cpu_hardirq_time
, delta
);
1924 else if (in_serving_softirq() && curr
!= this_cpu_ksoftirqd())
1925 __this_cpu_add(cpu_softirq_time
, delta
);
1927 irq_time_write_end();
1928 local_irq_restore(flags
);
1930 EXPORT_SYMBOL_GPL(account_system_vtime
);
1932 #endif /* CONFIG_IRQ_TIME_ACCOUNTING */
1934 #ifdef CONFIG_PARAVIRT
1935 static inline u64
steal_ticks(u64 steal
)
1937 if (unlikely(steal
> NSEC_PER_SEC
))
1938 return div_u64(steal
, TICK_NSEC
);
1940 return __iter_div_u64_rem(steal
, TICK_NSEC
, &steal
);
1944 static void update_rq_clock_task(struct rq
*rq
, s64 delta
)
1947 * In theory, the compile should just see 0 here, and optimize out the call
1948 * to sched_rt_avg_update. But I don't trust it...
1950 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
1951 s64 steal
= 0, irq_delta
= 0;
1953 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
1954 irq_delta
= irq_time_read(cpu_of(rq
)) - rq
->prev_irq_time
;
1957 * Since irq_time is only updated on {soft,}irq_exit, we might run into
1958 * this case when a previous update_rq_clock() happened inside a
1959 * {soft,}irq region.
1961 * When this happens, we stop ->clock_task and only update the
1962 * prev_irq_time stamp to account for the part that fit, so that a next
1963 * update will consume the rest. This ensures ->clock_task is
1966 * It does however cause some slight miss-attribution of {soft,}irq
1967 * time, a more accurate solution would be to update the irq_time using
1968 * the current rq->clock timestamp, except that would require using
1971 if (irq_delta
> delta
)
1974 rq
->prev_irq_time
+= irq_delta
;
1977 #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
1978 if (static_branch((¶virt_steal_rq_enabled
))) {
1981 steal
= paravirt_steal_clock(cpu_of(rq
));
1982 steal
-= rq
->prev_steal_time_rq
;
1984 if (unlikely(steal
> delta
))
1987 st
= steal_ticks(steal
);
1988 steal
= st
* TICK_NSEC
;
1990 rq
->prev_steal_time_rq
+= steal
;
1996 rq
->clock_task
+= delta
;
1998 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
1999 if ((irq_delta
+ steal
) && sched_feat(NONTASK_POWER
))
2000 sched_rt_avg_update(rq
, irq_delta
+ steal
);
2004 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
2005 static int irqtime_account_hi_update(void)
2007 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
2008 unsigned long flags
;
2012 local_irq_save(flags
);
2013 latest_ns
= this_cpu_read(cpu_hardirq_time
);
2014 if (cputime64_gt(nsecs_to_cputime64(latest_ns
), cpustat
->irq
))
2016 local_irq_restore(flags
);
2020 static int irqtime_account_si_update(void)
2022 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
2023 unsigned long flags
;
2027 local_irq_save(flags
);
2028 latest_ns
= this_cpu_read(cpu_softirq_time
);
2029 if (cputime64_gt(nsecs_to_cputime64(latest_ns
), cpustat
->softirq
))
2031 local_irq_restore(flags
);
2035 #else /* CONFIG_IRQ_TIME_ACCOUNTING */
2037 #define sched_clock_irqtime (0)
2041 #include "sched_idletask.c"
2042 #include "sched_fair.c"
2043 #include "sched_rt.c"
2044 #include "sched_autogroup.c"
2045 #include "sched_stoptask.c"
2046 #ifdef CONFIG_SCHED_DEBUG
2047 # include "sched_debug.c"
2050 void sched_set_stop_task(int cpu
, struct task_struct
*stop
)
2052 struct sched_param param
= { .sched_priority
= MAX_RT_PRIO
- 1 };
2053 struct task_struct
*old_stop
= cpu_rq(cpu
)->stop
;
2057 * Make it appear like a SCHED_FIFO task, its something
2058 * userspace knows about and won't get confused about.
2060 * Also, it will make PI more or less work without too
2061 * much confusion -- but then, stop work should not
2062 * rely on PI working anyway.
2064 sched_setscheduler_nocheck(stop
, SCHED_FIFO
, ¶m
);
2066 stop
->sched_class
= &stop_sched_class
;
2069 cpu_rq(cpu
)->stop
= stop
;
2073 * Reset it back to a normal scheduling class so that
2074 * it can die in pieces.
2076 old_stop
->sched_class
= &rt_sched_class
;
2081 * __normal_prio - return the priority that is based on the static prio
2083 static inline int __normal_prio(struct task_struct
*p
)
2085 return p
->static_prio
;
2089 * Calculate the expected normal priority: i.e. priority
2090 * without taking RT-inheritance into account. Might be
2091 * boosted by interactivity modifiers. Changes upon fork,
2092 * setprio syscalls, and whenever the interactivity
2093 * estimator recalculates.
2095 static inline int normal_prio(struct task_struct
*p
)
2099 if (task_has_rt_policy(p
))
2100 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
2102 prio
= __normal_prio(p
);
2107 * Calculate the current priority, i.e. the priority
2108 * taken into account by the scheduler. This value might
2109 * be boosted by RT tasks, or might be boosted by
2110 * interactivity modifiers. Will be RT if the task got
2111 * RT-boosted. If not then it returns p->normal_prio.
2113 static int effective_prio(struct task_struct
*p
)
2115 p
->normal_prio
= normal_prio(p
);
2117 * If we are RT tasks or we were boosted to RT priority,
2118 * keep the priority unchanged. Otherwise, update priority
2119 * to the normal priority:
2121 if (!rt_prio(p
->prio
))
2122 return p
->normal_prio
;
2127 * task_curr - is this task currently executing on a CPU?
2128 * @p: the task in question.
2130 inline int task_curr(const struct task_struct
*p
)
2132 return cpu_curr(task_cpu(p
)) == p
;
2135 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
2136 const struct sched_class
*prev_class
,
2139 if (prev_class
!= p
->sched_class
) {
2140 if (prev_class
->switched_from
)
2141 prev_class
->switched_from(rq
, p
);
2142 p
->sched_class
->switched_to(rq
, p
);
2143 } else if (oldprio
!= p
->prio
)
2144 p
->sched_class
->prio_changed(rq
, p
, oldprio
);
2147 static void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int flags
)
2149 const struct sched_class
*class;
2151 if (p
->sched_class
== rq
->curr
->sched_class
) {
2152 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
, flags
);
2154 for_each_class(class) {
2155 if (class == rq
->curr
->sched_class
)
2157 if (class == p
->sched_class
) {
2158 resched_task(rq
->curr
);
2165 * A queue event has occurred, and we're going to schedule. In
2166 * this case, we can save a useless back to back clock update.
2168 if (rq
->curr
->on_rq
&& test_tsk_need_resched(rq
->curr
))
2169 rq
->skip_clock_update
= 1;
2174 * Is this task likely cache-hot:
2177 task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
)
2181 if (p
->sched_class
!= &fair_sched_class
)
2184 if (unlikely(p
->policy
== SCHED_IDLE
))
2188 * Buddy candidates are cache hot:
2190 if (sched_feat(CACHE_HOT_BUDDY
) && this_rq()->nr_running
&&
2191 (&p
->se
== cfs_rq_of(&p
->se
)->next
||
2192 &p
->se
== cfs_rq_of(&p
->se
)->last
))
2195 if (sysctl_sched_migration_cost
== -1)
2197 if (sysctl_sched_migration_cost
== 0)
2200 delta
= now
- p
->se
.exec_start
;
2202 return delta
< (s64
)sysctl_sched_migration_cost
;
2205 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
2207 #ifdef CONFIG_SCHED_DEBUG
2209 * We should never call set_task_cpu() on a blocked task,
2210 * ttwu() will sort out the placement.
2212 WARN_ON_ONCE(p
->state
!= TASK_RUNNING
&& p
->state
!= TASK_WAKING
&&
2213 !(task_thread_info(p
)->preempt_count
& PREEMPT_ACTIVE
));
2215 #ifdef CONFIG_LOCKDEP
2217 * The caller should hold either p->pi_lock or rq->lock, when changing
2218 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
2220 * sched_move_task() holds both and thus holding either pins the cgroup,
2221 * see set_task_rq().
2223 * Furthermore, all task_rq users should acquire both locks, see
2226 WARN_ON_ONCE(debug_locks
&& !(lockdep_is_held(&p
->pi_lock
) ||
2227 lockdep_is_held(&task_rq(p
)->lock
)));
2231 trace_sched_migrate_task(p
, new_cpu
);
2233 if (task_cpu(p
) != new_cpu
) {
2234 p
->se
.nr_migrations
++;
2235 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS
, 1, NULL
, 0);
2238 __set_task_cpu(p
, new_cpu
);
2241 struct migration_arg
{
2242 struct task_struct
*task
;
2246 static int migration_cpu_stop(void *data
);
2249 * wait_task_inactive - wait for a thread to unschedule.
2251 * If @match_state is nonzero, it's the @p->state value just checked and
2252 * not expected to change. If it changes, i.e. @p might have woken up,
2253 * then return zero. When we succeed in waiting for @p to be off its CPU,
2254 * we return a positive number (its total switch count). If a second call
2255 * a short while later returns the same number, the caller can be sure that
2256 * @p has remained unscheduled the whole time.
2258 * The caller must ensure that the task *will* unschedule sometime soon,
2259 * else this function might spin for a *long* time. This function can't
2260 * be called with interrupts off, or it may introduce deadlock with
2261 * smp_call_function() if an IPI is sent by the same process we are
2262 * waiting to become inactive.
2264 unsigned long wait_task_inactive(struct task_struct
*p
, long match_state
)
2266 unsigned long flags
;
2273 * We do the initial early heuristics without holding
2274 * any task-queue locks at all. We'll only try to get
2275 * the runqueue lock when things look like they will
2281 * If the task is actively running on another CPU
2282 * still, just relax and busy-wait without holding
2285 * NOTE! Since we don't hold any locks, it's not
2286 * even sure that "rq" stays as the right runqueue!
2287 * But we don't care, since "task_running()" will
2288 * return false if the runqueue has changed and p
2289 * is actually now running somewhere else!
2291 while (task_running(rq
, p
)) {
2292 if (match_state
&& unlikely(p
->state
!= match_state
))
2298 * Ok, time to look more closely! We need the rq
2299 * lock now, to be *sure*. If we're wrong, we'll
2300 * just go back and repeat.
2302 rq
= task_rq_lock(p
, &flags
);
2303 trace_sched_wait_task(p
);
2304 running
= task_running(rq
, p
);
2307 if (!match_state
|| p
->state
== match_state
)
2308 ncsw
= p
->nvcsw
| LONG_MIN
; /* sets MSB */
2309 task_rq_unlock(rq
, p
, &flags
);
2312 * If it changed from the expected state, bail out now.
2314 if (unlikely(!ncsw
))
2318 * Was it really running after all now that we
2319 * checked with the proper locks actually held?
2321 * Oops. Go back and try again..
2323 if (unlikely(running
)) {
2329 * It's not enough that it's not actively running,
2330 * it must be off the runqueue _entirely_, and not
2333 * So if it was still runnable (but just not actively
2334 * running right now), it's preempted, and we should
2335 * yield - it could be a while.
2337 if (unlikely(on_rq
)) {
2338 ktime_t to
= ktime_set(0, NSEC_PER_SEC
/HZ
);
2340 set_current_state(TASK_UNINTERRUPTIBLE
);
2341 schedule_hrtimeout(&to
, HRTIMER_MODE_REL
);
2346 * Ahh, all good. It wasn't running, and it wasn't
2347 * runnable, which means that it will never become
2348 * running in the future either. We're all done!
2357 * kick_process - kick a running thread to enter/exit the kernel
2358 * @p: the to-be-kicked thread
2360 * Cause a process which is running on another CPU to enter
2361 * kernel-mode, without any delay. (to get signals handled.)
2363 * NOTE: this function doesn't have to take the runqueue lock,
2364 * because all it wants to ensure is that the remote task enters
2365 * the kernel. If the IPI races and the task has been migrated
2366 * to another CPU then no harm is done and the purpose has been
2369 void kick_process(struct task_struct
*p
)
2375 if ((cpu
!= smp_processor_id()) && task_curr(p
))
2376 smp_send_reschedule(cpu
);
2379 EXPORT_SYMBOL_GPL(kick_process
);
2380 #endif /* CONFIG_SMP */
2384 * ->cpus_allowed is protected by both rq->lock and p->pi_lock
2386 static int select_fallback_rq(int cpu
, struct task_struct
*p
)
2389 const struct cpumask
*nodemask
= cpumask_of_node(cpu_to_node(cpu
));
2391 /* Look for allowed, online CPU in same node. */
2392 for_each_cpu_and(dest_cpu
, nodemask
, cpu_active_mask
)
2393 if (cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
2396 /* Any allowed, online CPU? */
2397 dest_cpu
= cpumask_any_and(&p
->cpus_allowed
, cpu_active_mask
);
2398 if (dest_cpu
< nr_cpu_ids
)
2401 /* No more Mr. Nice Guy. */
2402 dest_cpu
= cpuset_cpus_allowed_fallback(p
);
2404 * Don't tell them about moving exiting tasks or
2405 * kernel threads (both mm NULL), since they never
2408 if (p
->mm
&& printk_ratelimit()) {
2409 printk(KERN_INFO
"process %d (%s) no longer affine to cpu%d\n",
2410 task_pid_nr(p
), p
->comm
, cpu
);
2417 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable.
2420 int select_task_rq(struct task_struct
*p
, int sd_flags
, int wake_flags
)
2422 int cpu
= p
->sched_class
->select_task_rq(p
, sd_flags
, wake_flags
);
2425 * In order not to call set_task_cpu() on a blocking task we need
2426 * to rely on ttwu() to place the task on a valid ->cpus_allowed
2429 * Since this is common to all placement strategies, this lives here.
2431 * [ this allows ->select_task() to simply return task_cpu(p) and
2432 * not worry about this generic constraint ]
2434 if (unlikely(!cpumask_test_cpu(cpu
, &p
->cpus_allowed
) ||
2436 cpu
= select_fallback_rq(task_cpu(p
), p
);
2441 static void update_avg(u64
*avg
, u64 sample
)
2443 s64 diff
= sample
- *avg
;
2449 ttwu_stat(struct task_struct
*p
, int cpu
, int wake_flags
)
2451 #ifdef CONFIG_SCHEDSTATS
2452 struct rq
*rq
= this_rq();
2455 int this_cpu
= smp_processor_id();
2457 if (cpu
== this_cpu
) {
2458 schedstat_inc(rq
, ttwu_local
);
2459 schedstat_inc(p
, se
.statistics
.nr_wakeups_local
);
2461 struct sched_domain
*sd
;
2463 schedstat_inc(p
, se
.statistics
.nr_wakeups_remote
);
2465 for_each_domain(this_cpu
, sd
) {
2466 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
2467 schedstat_inc(sd
, ttwu_wake_remote
);
2474 if (wake_flags
& WF_MIGRATED
)
2475 schedstat_inc(p
, se
.statistics
.nr_wakeups_migrate
);
2477 #endif /* CONFIG_SMP */
2479 schedstat_inc(rq
, ttwu_count
);
2480 schedstat_inc(p
, se
.statistics
.nr_wakeups
);
2482 if (wake_flags
& WF_SYNC
)
2483 schedstat_inc(p
, se
.statistics
.nr_wakeups_sync
);
2485 #endif /* CONFIG_SCHEDSTATS */
2488 static void ttwu_activate(struct rq
*rq
, struct task_struct
*p
, int en_flags
)
2490 activate_task(rq
, p
, en_flags
);
2493 /* if a worker is waking up, notify workqueue */
2494 if (p
->flags
& PF_WQ_WORKER
)
2495 wq_worker_waking_up(p
, cpu_of(rq
));
2499 * Mark the task runnable and perform wakeup-preemption.
2502 ttwu_do_wakeup(struct rq
*rq
, struct task_struct
*p
, int wake_flags
)
2504 trace_sched_wakeup(p
, true);
2505 check_preempt_curr(rq
, p
, wake_flags
);
2507 p
->state
= TASK_RUNNING
;
2509 if (p
->sched_class
->task_woken
)
2510 p
->sched_class
->task_woken(rq
, p
);
2512 if (rq
->idle_stamp
) {
2513 u64 delta
= rq
->clock
- rq
->idle_stamp
;
2514 u64 max
= 2*sysctl_sched_migration_cost
;
2519 update_avg(&rq
->avg_idle
, delta
);
2526 ttwu_do_activate(struct rq
*rq
, struct task_struct
*p
, int wake_flags
)
2529 if (p
->sched_contributes_to_load
)
2530 rq
->nr_uninterruptible
--;
2533 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
| ENQUEUE_WAKING
);
2534 ttwu_do_wakeup(rq
, p
, wake_flags
);
2538 * Called in case the task @p isn't fully descheduled from its runqueue,
2539 * in this case we must do a remote wakeup. Its a 'light' wakeup though,
2540 * since all we need to do is flip p->state to TASK_RUNNING, since
2541 * the task is still ->on_rq.
2543 static int ttwu_remote(struct task_struct
*p
, int wake_flags
)
2548 rq
= __task_rq_lock(p
);
2550 ttwu_do_wakeup(rq
, p
, wake_flags
);
2553 __task_rq_unlock(rq
);
2559 static void sched_ttwu_do_pending(struct task_struct
*list
)
2561 struct rq
*rq
= this_rq();
2563 raw_spin_lock(&rq
->lock
);
2566 struct task_struct
*p
= list
;
2567 list
= list
->wake_entry
;
2568 ttwu_do_activate(rq
, p
, 0);
2571 raw_spin_unlock(&rq
->lock
);
2574 #ifdef CONFIG_HOTPLUG_CPU
2576 static void sched_ttwu_pending(void)
2578 struct rq
*rq
= this_rq();
2579 struct task_struct
*list
= xchg(&rq
->wake_list
, NULL
);
2584 sched_ttwu_do_pending(list
);
2587 #endif /* CONFIG_HOTPLUG_CPU */
2589 void scheduler_ipi(void)
2591 struct rq
*rq
= this_rq();
2592 struct task_struct
*list
= xchg(&rq
->wake_list
, NULL
);
2598 * Not all reschedule IPI handlers call irq_enter/irq_exit, since
2599 * traditionally all their work was done from the interrupt return
2600 * path. Now that we actually do some work, we need to make sure
2603 * Some archs already do call them, luckily irq_enter/exit nest
2606 * Arguably we should visit all archs and update all handlers,
2607 * however a fair share of IPIs are still resched only so this would
2608 * somewhat pessimize the simple resched case.
2611 sched_ttwu_do_pending(list
);
2615 static void ttwu_queue_remote(struct task_struct
*p
, int cpu
)
2617 struct rq
*rq
= cpu_rq(cpu
);
2618 struct task_struct
*next
= rq
->wake_list
;
2621 struct task_struct
*old
= next
;
2623 p
->wake_entry
= next
;
2624 next
= cmpxchg(&rq
->wake_list
, old
, p
);
2630 smp_send_reschedule(cpu
);
2633 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
2634 static int ttwu_activate_remote(struct task_struct
*p
, int wake_flags
)
2639 rq
= __task_rq_lock(p
);
2641 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
);
2642 ttwu_do_wakeup(rq
, p
, wake_flags
);
2645 __task_rq_unlock(rq
);
2650 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
2651 #endif /* CONFIG_SMP */
2653 static void ttwu_queue(struct task_struct
*p
, int cpu
)
2655 struct rq
*rq
= cpu_rq(cpu
);
2657 #if defined(CONFIG_SMP)
2658 if (sched_feat(TTWU_QUEUE
) && cpu
!= smp_processor_id()) {
2659 sched_clock_cpu(cpu
); /* sync clocks x-cpu */
2660 ttwu_queue_remote(p
, cpu
);
2665 raw_spin_lock(&rq
->lock
);
2666 ttwu_do_activate(rq
, p
, 0);
2667 raw_spin_unlock(&rq
->lock
);
2671 * try_to_wake_up - wake up a thread
2672 * @p: the thread to be awakened
2673 * @state: the mask of task states that can be woken
2674 * @wake_flags: wake modifier flags (WF_*)
2676 * Put it on the run-queue if it's not already there. The "current"
2677 * thread is always on the run-queue (except when the actual
2678 * re-schedule is in progress), and as such you're allowed to do
2679 * the simpler "current->state = TASK_RUNNING" to mark yourself
2680 * runnable without the overhead of this.
2682 * Returns %true if @p was woken up, %false if it was already running
2683 * or @state didn't match @p's state.
2686 try_to_wake_up(struct task_struct
*p
, unsigned int state
, int wake_flags
)
2688 unsigned long flags
;
2689 int cpu
, success
= 0;
2692 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
2693 if (!(p
->state
& state
))
2696 success
= 1; /* we're going to change ->state */
2699 if (p
->on_rq
&& ttwu_remote(p
, wake_flags
))
2704 * If the owning (remote) cpu is still in the middle of schedule() with
2705 * this task as prev, wait until its done referencing the task.
2708 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
2710 * In case the architecture enables interrupts in
2711 * context_switch(), we cannot busy wait, since that
2712 * would lead to deadlocks when an interrupt hits and
2713 * tries to wake up @prev. So bail and do a complete
2716 if (ttwu_activate_remote(p
, wake_flags
))
2723 * Pairs with the smp_wmb() in finish_lock_switch().
2727 p
->sched_contributes_to_load
= !!task_contributes_to_load(p
);
2728 p
->state
= TASK_WAKING
;
2730 if (p
->sched_class
->task_waking
)
2731 p
->sched_class
->task_waking(p
);
2733 cpu
= select_task_rq(p
, SD_BALANCE_WAKE
, wake_flags
);
2734 if (task_cpu(p
) != cpu
) {
2735 wake_flags
|= WF_MIGRATED
;
2736 set_task_cpu(p
, cpu
);
2738 #endif /* CONFIG_SMP */
2742 ttwu_stat(p
, cpu
, wake_flags
);
2744 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2750 * try_to_wake_up_local - try to wake up a local task with rq lock held
2751 * @p: the thread to be awakened
2753 * Put @p on the run-queue if it's not already there. The caller must
2754 * ensure that this_rq() is locked, @p is bound to this_rq() and not
2757 static void try_to_wake_up_local(struct task_struct
*p
)
2759 struct rq
*rq
= task_rq(p
);
2761 BUG_ON(rq
!= this_rq());
2762 BUG_ON(p
== current
);
2763 lockdep_assert_held(&rq
->lock
);
2765 if (!raw_spin_trylock(&p
->pi_lock
)) {
2766 raw_spin_unlock(&rq
->lock
);
2767 raw_spin_lock(&p
->pi_lock
);
2768 raw_spin_lock(&rq
->lock
);
2771 if (!(p
->state
& TASK_NORMAL
))
2775 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
);
2777 ttwu_do_wakeup(rq
, p
, 0);
2778 ttwu_stat(p
, smp_processor_id(), 0);
2780 raw_spin_unlock(&p
->pi_lock
);
2784 * wake_up_process - Wake up a specific process
2785 * @p: The process to be woken up.
2787 * Attempt to wake up the nominated process and move it to the set of runnable
2788 * processes. Returns 1 if the process was woken up, 0 if it was already
2791 * It may be assumed that this function implies a write memory barrier before
2792 * changing the task state if and only if any tasks are woken up.
2794 int wake_up_process(struct task_struct
*p
)
2796 return try_to_wake_up(p
, TASK_ALL
, 0);
2798 EXPORT_SYMBOL(wake_up_process
);
2800 int wake_up_state(struct task_struct
*p
, unsigned int state
)
2802 return try_to_wake_up(p
, state
, 0);
2806 * Perform scheduler related setup for a newly forked process p.
2807 * p is forked by current.
2809 * __sched_fork() is basic setup used by init_idle() too:
2811 static void __sched_fork(struct task_struct
*p
)
2816 p
->se
.exec_start
= 0;
2817 p
->se
.sum_exec_runtime
= 0;
2818 p
->se
.prev_sum_exec_runtime
= 0;
2819 p
->se
.nr_migrations
= 0;
2821 INIT_LIST_HEAD(&p
->se
.group_node
);
2823 #ifdef CONFIG_SCHEDSTATS
2824 memset(&p
->se
.statistics
, 0, sizeof(p
->se
.statistics
));
2827 INIT_LIST_HEAD(&p
->rt
.run_list
);
2829 #ifdef CONFIG_PREEMPT_NOTIFIERS
2830 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
2835 * fork()/clone()-time setup:
2837 void sched_fork(struct task_struct
*p
)
2839 unsigned long flags
;
2840 int cpu
= get_cpu();
2844 * We mark the process as running here. This guarantees that
2845 * nobody will actually run it, and a signal or other external
2846 * event cannot wake it up and insert it on the runqueue either.
2848 p
->state
= TASK_RUNNING
;
2851 * Revert to default priority/policy on fork if requested.
2853 if (unlikely(p
->sched_reset_on_fork
)) {
2854 if (p
->policy
== SCHED_FIFO
|| p
->policy
== SCHED_RR
) {
2855 p
->policy
= SCHED_NORMAL
;
2856 p
->normal_prio
= p
->static_prio
;
2859 if (PRIO_TO_NICE(p
->static_prio
) < 0) {
2860 p
->static_prio
= NICE_TO_PRIO(0);
2861 p
->normal_prio
= p
->static_prio
;
2866 * We don't need the reset flag anymore after the fork. It has
2867 * fulfilled its duty:
2869 p
->sched_reset_on_fork
= 0;
2873 * Make sure we do not leak PI boosting priority to the child.
2875 p
->prio
= current
->normal_prio
;
2877 if (!rt_prio(p
->prio
))
2878 p
->sched_class
= &fair_sched_class
;
2880 if (p
->sched_class
->task_fork
)
2881 p
->sched_class
->task_fork(p
);
2884 * The child is not yet in the pid-hash so no cgroup attach races,
2885 * and the cgroup is pinned to this child due to cgroup_fork()
2886 * is ran before sched_fork().
2888 * Silence PROVE_RCU.
2890 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
2891 set_task_cpu(p
, cpu
);
2892 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2894 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2895 if (likely(sched_info_on()))
2896 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
2898 #if defined(CONFIG_SMP)
2901 #ifdef CONFIG_PREEMPT_COUNT
2902 /* Want to start with kernel preemption disabled. */
2903 task_thread_info(p
)->preempt_count
= 1;
2906 plist_node_init(&p
->pushable_tasks
, MAX_PRIO
);
2913 * wake_up_new_task - wake up a newly created task for the first time.
2915 * This function will do some initial scheduler statistics housekeeping
2916 * that must be done for every newly created context, then puts the task
2917 * on the runqueue and wakes it.
2919 void wake_up_new_task(struct task_struct
*p
)
2921 unsigned long flags
;
2924 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
2927 * Fork balancing, do it here and not earlier because:
2928 * - cpus_allowed can change in the fork path
2929 * - any previously selected cpu might disappear through hotplug
2931 set_task_cpu(p
, select_task_rq(p
, SD_BALANCE_FORK
, 0));
2934 rq
= __task_rq_lock(p
);
2935 activate_task(rq
, p
, 0);
2937 trace_sched_wakeup_new(p
, true);
2938 check_preempt_curr(rq
, p
, WF_FORK
);
2940 if (p
->sched_class
->task_woken
)
2941 p
->sched_class
->task_woken(rq
, p
);
2943 task_rq_unlock(rq
, p
, &flags
);
2946 #ifdef CONFIG_PREEMPT_NOTIFIERS
2949 * preempt_notifier_register - tell me when current is being preempted & rescheduled
2950 * @notifier: notifier struct to register
2952 void preempt_notifier_register(struct preempt_notifier
*notifier
)
2954 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
2956 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
2959 * preempt_notifier_unregister - no longer interested in preemption notifications
2960 * @notifier: notifier struct to unregister
2962 * This is safe to call from within a preemption notifier.
2964 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
2966 hlist_del(¬ifier
->link
);
2968 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
2970 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2972 struct preempt_notifier
*notifier
;
2973 struct hlist_node
*node
;
2975 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2976 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
2980 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2981 struct task_struct
*next
)
2983 struct preempt_notifier
*notifier
;
2984 struct hlist_node
*node
;
2986 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2987 notifier
->ops
->sched_out(notifier
, next
);
2990 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2992 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2997 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2998 struct task_struct
*next
)
3002 #endif /* CONFIG_PREEMPT_NOTIFIERS */
3005 * prepare_task_switch - prepare to switch tasks
3006 * @rq: the runqueue preparing to switch
3007 * @prev: the current task that is being switched out
3008 * @next: the task we are going to switch to.
3010 * This is called with the rq lock held and interrupts off. It must
3011 * be paired with a subsequent finish_task_switch after the context
3014 * prepare_task_switch sets up locking and calls architecture specific
3018 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
3019 struct task_struct
*next
)
3021 sched_info_switch(prev
, next
);
3022 perf_event_task_sched_out(prev
, next
);
3023 fire_sched_out_preempt_notifiers(prev
, next
);
3024 prepare_lock_switch(rq
, next
);
3025 prepare_arch_switch(next
);
3026 trace_sched_switch(prev
, next
);
3030 * finish_task_switch - clean up after a task-switch
3031 * @rq: runqueue associated with task-switch
3032 * @prev: the thread we just switched away from.
3034 * finish_task_switch must be called after the context switch, paired
3035 * with a prepare_task_switch call before the context switch.
3036 * finish_task_switch will reconcile locking set up by prepare_task_switch,
3037 * and do any other architecture-specific cleanup actions.
3039 * Note that we may have delayed dropping an mm in context_switch(). If
3040 * so, we finish that here outside of the runqueue lock. (Doing it
3041 * with the lock held can cause deadlocks; see schedule() for
3044 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
3045 __releases(rq
->lock
)
3047 struct mm_struct
*mm
= rq
->prev_mm
;
3053 * A task struct has one reference for the use as "current".
3054 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
3055 * schedule one last time. The schedule call will never return, and
3056 * the scheduled task must drop that reference.
3057 * The test for TASK_DEAD must occur while the runqueue locks are
3058 * still held, otherwise prev could be scheduled on another cpu, die
3059 * there before we look at prev->state, and then the reference would
3061 * Manfred Spraul <manfred@colorfullife.com>
3063 prev_state
= prev
->state
;
3064 finish_arch_switch(prev
);
3065 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
3066 local_irq_disable();
3067 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
3068 perf_event_task_sched_in(current
);
3069 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
3071 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
3072 finish_lock_switch(rq
, prev
);
3074 fire_sched_in_preempt_notifiers(current
);
3077 if (unlikely(prev_state
== TASK_DEAD
)) {
3079 * Remove function-return probe instances associated with this
3080 * task and put them back on the free list.
3082 kprobe_flush_task(prev
);
3083 put_task_struct(prev
);
3089 /* assumes rq->lock is held */
3090 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*prev
)
3092 if (prev
->sched_class
->pre_schedule
)
3093 prev
->sched_class
->pre_schedule(rq
, prev
);
3096 /* rq->lock is NOT held, but preemption is disabled */
3097 static inline void post_schedule(struct rq
*rq
)
3099 if (rq
->post_schedule
) {
3100 unsigned long flags
;
3102 raw_spin_lock_irqsave(&rq
->lock
, flags
);
3103 if (rq
->curr
->sched_class
->post_schedule
)
3104 rq
->curr
->sched_class
->post_schedule(rq
);
3105 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
3107 rq
->post_schedule
= 0;
3113 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*p
)
3117 static inline void post_schedule(struct rq
*rq
)
3124 * schedule_tail - first thing a freshly forked thread must call.
3125 * @prev: the thread we just switched away from.
3127 asmlinkage
void schedule_tail(struct task_struct
*prev
)
3128 __releases(rq
->lock
)
3130 struct rq
*rq
= this_rq();
3132 finish_task_switch(rq
, prev
);
3135 * FIXME: do we need to worry about rq being invalidated by the
3140 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
3141 /* In this case, finish_task_switch does not reenable preemption */
3144 if (current
->set_child_tid
)
3145 put_user(task_pid_vnr(current
), current
->set_child_tid
);
3149 * context_switch - switch to the new MM and the new
3150 * thread's register state.
3153 context_switch(struct rq
*rq
, struct task_struct
*prev
,
3154 struct task_struct
*next
)
3156 struct mm_struct
*mm
, *oldmm
;
3158 prepare_task_switch(rq
, prev
, next
);
3161 oldmm
= prev
->active_mm
;
3163 * For paravirt, this is coupled with an exit in switch_to to
3164 * combine the page table reload and the switch backend into
3167 arch_start_context_switch(prev
);
3170 next
->active_mm
= oldmm
;
3171 atomic_inc(&oldmm
->mm_count
);
3172 enter_lazy_tlb(oldmm
, next
);
3174 switch_mm(oldmm
, mm
, next
);
3177 prev
->active_mm
= NULL
;
3178 rq
->prev_mm
= oldmm
;
3181 * Since the runqueue lock will be released by the next
3182 * task (which is an invalid locking op but in the case
3183 * of the scheduler it's an obvious special-case), so we
3184 * do an early lockdep release here:
3186 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
3187 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
3190 /* Here we just switch the register state and the stack. */
3191 switch_to(prev
, next
, prev
);
3195 * this_rq must be evaluated again because prev may have moved
3196 * CPUs since it called schedule(), thus the 'rq' on its stack
3197 * frame will be invalid.
3199 finish_task_switch(this_rq(), prev
);
3203 * nr_running, nr_uninterruptible and nr_context_switches:
3205 * externally visible scheduler statistics: current number of runnable
3206 * threads, current number of uninterruptible-sleeping threads, total
3207 * number of context switches performed since bootup.
3209 unsigned long nr_running(void)
3211 unsigned long i
, sum
= 0;
3213 for_each_online_cpu(i
)
3214 sum
+= cpu_rq(i
)->nr_running
;
3219 unsigned long nr_uninterruptible(void)
3221 unsigned long i
, sum
= 0;
3223 for_each_possible_cpu(i
)
3224 sum
+= cpu_rq(i
)->nr_uninterruptible
;
3227 * Since we read the counters lockless, it might be slightly
3228 * inaccurate. Do not allow it to go below zero though:
3230 if (unlikely((long)sum
< 0))
3236 unsigned long long nr_context_switches(void)
3239 unsigned long long sum
= 0;
3241 for_each_possible_cpu(i
)
3242 sum
+= cpu_rq(i
)->nr_switches
;
3247 unsigned long nr_iowait(void)
3249 unsigned long i
, sum
= 0;
3251 for_each_possible_cpu(i
)
3252 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
3257 unsigned long nr_iowait_cpu(int cpu
)
3259 struct rq
*this = cpu_rq(cpu
);
3260 return atomic_read(&this->nr_iowait
);
3263 unsigned long this_cpu_load(void)
3265 struct rq
*this = this_rq();
3266 return this->cpu_load
[0];
3270 /* Variables and functions for calc_load */
3271 static atomic_long_t calc_load_tasks
;
3272 static unsigned long calc_load_update
;
3273 unsigned long avenrun
[3];
3274 EXPORT_SYMBOL(avenrun
);
3276 static long calc_load_fold_active(struct rq
*this_rq
)
3278 long nr_active
, delta
= 0;
3280 nr_active
= this_rq
->nr_running
;
3281 nr_active
+= (long) this_rq
->nr_uninterruptible
;
3283 if (nr_active
!= this_rq
->calc_load_active
) {
3284 delta
= nr_active
- this_rq
->calc_load_active
;
3285 this_rq
->calc_load_active
= nr_active
;
3291 static unsigned long
3292 calc_load(unsigned long load
, unsigned long exp
, unsigned long active
)
3295 load
+= active
* (FIXED_1
- exp
);
3296 load
+= 1UL << (FSHIFT
- 1);
3297 return load
>> FSHIFT
;
3302 * For NO_HZ we delay the active fold to the next LOAD_FREQ update.
3304 * When making the ILB scale, we should try to pull this in as well.
3306 static atomic_long_t calc_load_tasks_idle
;
3308 static void calc_load_account_idle(struct rq
*this_rq
)
3312 delta
= calc_load_fold_active(this_rq
);
3314 atomic_long_add(delta
, &calc_load_tasks_idle
);
3317 static long calc_load_fold_idle(void)
3322 * Its got a race, we don't care...
3324 if (atomic_long_read(&calc_load_tasks_idle
))
3325 delta
= atomic_long_xchg(&calc_load_tasks_idle
, 0);
3331 * fixed_power_int - compute: x^n, in O(log n) time
3333 * @x: base of the power
3334 * @frac_bits: fractional bits of @x
3335 * @n: power to raise @x to.
3337 * By exploiting the relation between the definition of the natural power
3338 * function: x^n := x*x*...*x (x multiplied by itself for n times), and
3339 * the binary encoding of numbers used by computers: n := \Sum n_i * 2^i,
3340 * (where: n_i \elem {0, 1}, the binary vector representing n),
3341 * we find: x^n := x^(\Sum n_i * 2^i) := \Prod x^(n_i * 2^i), which is
3342 * of course trivially computable in O(log_2 n), the length of our binary
3345 static unsigned long
3346 fixed_power_int(unsigned long x
, unsigned int frac_bits
, unsigned int n
)
3348 unsigned long result
= 1UL << frac_bits
;
3353 result
+= 1UL << (frac_bits
- 1);
3354 result
>>= frac_bits
;
3360 x
+= 1UL << (frac_bits
- 1);
3368 * a1 = a0 * e + a * (1 - e)
3370 * a2 = a1 * e + a * (1 - e)
3371 * = (a0 * e + a * (1 - e)) * e + a * (1 - e)
3372 * = a0 * e^2 + a * (1 - e) * (1 + e)
3374 * a3 = a2 * e + a * (1 - e)
3375 * = (a0 * e^2 + a * (1 - e) * (1 + e)) * e + a * (1 - e)
3376 * = a0 * e^3 + a * (1 - e) * (1 + e + e^2)
3380 * an = a0 * e^n + a * (1 - e) * (1 + e + ... + e^n-1) [1]
3381 * = a0 * e^n + a * (1 - e) * (1 - e^n)/(1 - e)
3382 * = a0 * e^n + a * (1 - e^n)
3384 * [1] application of the geometric series:
3387 * S_n := \Sum x^i = -------------
3390 static unsigned long
3391 calc_load_n(unsigned long load
, unsigned long exp
,
3392 unsigned long active
, unsigned int n
)
3395 return calc_load(load
, fixed_power_int(exp
, FSHIFT
, n
), active
);
3399 * NO_HZ can leave us missing all per-cpu ticks calling
3400 * calc_load_account_active(), but since an idle CPU folds its delta into
3401 * calc_load_tasks_idle per calc_load_account_idle(), all we need to do is fold
3402 * in the pending idle delta if our idle period crossed a load cycle boundary.
3404 * Once we've updated the global active value, we need to apply the exponential
3405 * weights adjusted to the number of cycles missed.
3407 static void calc_global_nohz(unsigned long ticks
)
3409 long delta
, active
, n
;
3411 if (time_before(jiffies
, calc_load_update
))
3415 * If we crossed a calc_load_update boundary, make sure to fold
3416 * any pending idle changes, the respective CPUs might have
3417 * missed the tick driven calc_load_account_active() update
3420 delta
= calc_load_fold_idle();
3422 atomic_long_add(delta
, &calc_load_tasks
);
3425 * If we were idle for multiple load cycles, apply them.
3427 if (ticks
>= LOAD_FREQ
) {
3428 n
= ticks
/ LOAD_FREQ
;
3430 active
= atomic_long_read(&calc_load_tasks
);
3431 active
= active
> 0 ? active
* FIXED_1
: 0;
3433 avenrun
[0] = calc_load_n(avenrun
[0], EXP_1
, active
, n
);
3434 avenrun
[1] = calc_load_n(avenrun
[1], EXP_5
, active
, n
);
3435 avenrun
[2] = calc_load_n(avenrun
[2], EXP_15
, active
, n
);
3437 calc_load_update
+= n
* LOAD_FREQ
;
3441 * Its possible the remainder of the above division also crosses
3442 * a LOAD_FREQ period, the regular check in calc_global_load()
3443 * which comes after this will take care of that.
3445 * Consider us being 11 ticks before a cycle completion, and us
3446 * sleeping for 4*LOAD_FREQ + 22 ticks, then the above code will
3447 * age us 4 cycles, and the test in calc_global_load() will
3448 * pick up the final one.
3452 static void calc_load_account_idle(struct rq
*this_rq
)
3456 static inline long calc_load_fold_idle(void)
3461 static void calc_global_nohz(unsigned long ticks
)
3467 * get_avenrun - get the load average array
3468 * @loads: pointer to dest load array
3469 * @offset: offset to add
3470 * @shift: shift count to shift the result left
3472 * These values are estimates at best, so no need for locking.
3474 void get_avenrun(unsigned long *loads
, unsigned long offset
, int shift
)
3476 loads
[0] = (avenrun
[0] + offset
) << shift
;
3477 loads
[1] = (avenrun
[1] + offset
) << shift
;
3478 loads
[2] = (avenrun
[2] + offset
) << shift
;
3482 * calc_load - update the avenrun load estimates 10 ticks after the
3483 * CPUs have updated calc_load_tasks.
3485 void calc_global_load(unsigned long ticks
)
3489 calc_global_nohz(ticks
);
3491 if (time_before(jiffies
, calc_load_update
+ 10))
3494 active
= atomic_long_read(&calc_load_tasks
);
3495 active
= active
> 0 ? active
* FIXED_1
: 0;
3497 avenrun
[0] = calc_load(avenrun
[0], EXP_1
, active
);
3498 avenrun
[1] = calc_load(avenrun
[1], EXP_5
, active
);
3499 avenrun
[2] = calc_load(avenrun
[2], EXP_15
, active
);
3501 calc_load_update
+= LOAD_FREQ
;
3505 * Called from update_cpu_load() to periodically update this CPU's
3508 static void calc_load_account_active(struct rq
*this_rq
)
3512 if (time_before(jiffies
, this_rq
->calc_load_update
))
3515 delta
= calc_load_fold_active(this_rq
);
3516 delta
+= calc_load_fold_idle();
3518 atomic_long_add(delta
, &calc_load_tasks
);
3520 this_rq
->calc_load_update
+= LOAD_FREQ
;
3524 * The exact cpuload at various idx values, calculated at every tick would be
3525 * load = (2^idx - 1) / 2^idx * load + 1 / 2^idx * cur_load
3527 * If a cpu misses updates for n-1 ticks (as it was idle) and update gets called
3528 * on nth tick when cpu may be busy, then we have:
3529 * load = ((2^idx - 1) / 2^idx)^(n-1) * load
3530 * load = (2^idx - 1) / 2^idx) * load + 1 / 2^idx * cur_load
3532 * decay_load_missed() below does efficient calculation of
3533 * load = ((2^idx - 1) / 2^idx)^(n-1) * load
3534 * avoiding 0..n-1 loop doing load = ((2^idx - 1) / 2^idx) * load
3536 * The calculation is approximated on a 128 point scale.
3537 * degrade_zero_ticks is the number of ticks after which load at any
3538 * particular idx is approximated to be zero.
3539 * degrade_factor is a precomputed table, a row for each load idx.
3540 * Each column corresponds to degradation factor for a power of two ticks,
3541 * based on 128 point scale.
3543 * row 2, col 3 (=12) says that the degradation at load idx 2 after
3544 * 8 ticks is 12/128 (which is an approximation of exact factor 3^8/4^8).
3546 * With this power of 2 load factors, we can degrade the load n times
3547 * by looking at 1 bits in n and doing as many mult/shift instead of
3548 * n mult/shifts needed by the exact degradation.
3550 #define DEGRADE_SHIFT 7
3551 static const unsigned char
3552 degrade_zero_ticks
[CPU_LOAD_IDX_MAX
] = {0, 8, 32, 64, 128};
3553 static const unsigned char
3554 degrade_factor
[CPU_LOAD_IDX_MAX
][DEGRADE_SHIFT
+ 1] = {
3555 {0, 0, 0, 0, 0, 0, 0, 0},
3556 {64, 32, 8, 0, 0, 0, 0, 0},
3557 {96, 72, 40, 12, 1, 0, 0},
3558 {112, 98, 75, 43, 15, 1, 0},
3559 {120, 112, 98, 76, 45, 16, 2} };
3562 * Update cpu_load for any missed ticks, due to tickless idle. The backlog
3563 * would be when CPU is idle and so we just decay the old load without
3564 * adding any new load.
3566 static unsigned long
3567 decay_load_missed(unsigned long load
, unsigned long missed_updates
, int idx
)
3571 if (!missed_updates
)
3574 if (missed_updates
>= degrade_zero_ticks
[idx
])
3578 return load
>> missed_updates
;
3580 while (missed_updates
) {
3581 if (missed_updates
% 2)
3582 load
= (load
* degrade_factor
[idx
][j
]) >> DEGRADE_SHIFT
;
3584 missed_updates
>>= 1;
3591 * Update rq->cpu_load[] statistics. This function is usually called every
3592 * scheduler tick (TICK_NSEC). With tickless idle this will not be called
3593 * every tick. We fix it up based on jiffies.
3595 static void update_cpu_load(struct rq
*this_rq
)
3597 unsigned long this_load
= this_rq
->load
.weight
;
3598 unsigned long curr_jiffies
= jiffies
;
3599 unsigned long pending_updates
;
3602 this_rq
->nr_load_updates
++;
3604 /* Avoid repeated calls on same jiffy, when moving in and out of idle */
3605 if (curr_jiffies
== this_rq
->last_load_update_tick
)
3608 pending_updates
= curr_jiffies
- this_rq
->last_load_update_tick
;
3609 this_rq
->last_load_update_tick
= curr_jiffies
;
3611 /* Update our load: */
3612 this_rq
->cpu_load
[0] = this_load
; /* Fasttrack for idx 0 */
3613 for (i
= 1, scale
= 2; i
< CPU_LOAD_IDX_MAX
; i
++, scale
+= scale
) {
3614 unsigned long old_load
, new_load
;
3616 /* scale is effectively 1 << i now, and >> i divides by scale */
3618 old_load
= this_rq
->cpu_load
[i
];
3619 old_load
= decay_load_missed(old_load
, pending_updates
- 1, i
);
3620 new_load
= this_load
;
3622 * Round up the averaging division if load is increasing. This
3623 * prevents us from getting stuck on 9 if the load is 10, for
3626 if (new_load
> old_load
)
3627 new_load
+= scale
- 1;
3629 this_rq
->cpu_load
[i
] = (old_load
* (scale
- 1) + new_load
) >> i
;
3632 sched_avg_update(this_rq
);
3635 static void update_cpu_load_active(struct rq
*this_rq
)
3637 update_cpu_load(this_rq
);
3639 calc_load_account_active(this_rq
);
3645 * sched_exec - execve() is a valuable balancing opportunity, because at
3646 * this point the task has the smallest effective memory and cache footprint.
3648 void sched_exec(void)
3650 struct task_struct
*p
= current
;
3651 unsigned long flags
;
3654 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
3655 dest_cpu
= p
->sched_class
->select_task_rq(p
, SD_BALANCE_EXEC
, 0);
3656 if (dest_cpu
== smp_processor_id())
3659 if (likely(cpu_active(dest_cpu
))) {
3660 struct migration_arg arg
= { p
, dest_cpu
};
3662 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
3663 stop_one_cpu(task_cpu(p
), migration_cpu_stop
, &arg
);
3667 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
3672 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
3674 EXPORT_PER_CPU_SYMBOL(kstat
);
3677 * Return any ns on the sched_clock that have not yet been accounted in
3678 * @p in case that task is currently running.
3680 * Called with task_rq_lock() held on @rq.
3682 static u64
do_task_delta_exec(struct task_struct
*p
, struct rq
*rq
)
3686 if (task_current(rq
, p
)) {
3687 update_rq_clock(rq
);
3688 ns
= rq
->clock_task
- p
->se
.exec_start
;
3696 unsigned long long task_delta_exec(struct task_struct
*p
)
3698 unsigned long flags
;
3702 rq
= task_rq_lock(p
, &flags
);
3703 ns
= do_task_delta_exec(p
, rq
);
3704 task_rq_unlock(rq
, p
, &flags
);
3710 * Return accounted runtime for the task.
3711 * In case the task is currently running, return the runtime plus current's
3712 * pending runtime that have not been accounted yet.
3714 unsigned long long task_sched_runtime(struct task_struct
*p
)
3716 unsigned long flags
;
3720 rq
= task_rq_lock(p
, &flags
);
3721 ns
= p
->se
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
3722 task_rq_unlock(rq
, p
, &flags
);
3728 * Return sum_exec_runtime for the thread group.
3729 * In case the task is currently running, return the sum plus current's
3730 * pending runtime that have not been accounted yet.
3732 * Note that the thread group might have other running tasks as well,
3733 * so the return value not includes other pending runtime that other
3734 * running tasks might have.
3736 unsigned long long thread_group_sched_runtime(struct task_struct
*p
)
3738 struct task_cputime totals
;
3739 unsigned long flags
;
3743 rq
= task_rq_lock(p
, &flags
);
3744 thread_group_cputime(p
, &totals
);
3745 ns
= totals
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
3746 task_rq_unlock(rq
, p
, &flags
);
3752 * Account user cpu time to a process.
3753 * @p: the process that the cpu time gets accounted to
3754 * @cputime: the cpu time spent in user space since the last update
3755 * @cputime_scaled: cputime scaled by cpu frequency
3757 void account_user_time(struct task_struct
*p
, cputime_t cputime
,
3758 cputime_t cputime_scaled
)
3760 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3763 /* Add user time to process. */
3764 p
->utime
= cputime_add(p
->utime
, cputime
);
3765 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
3766 account_group_user_time(p
, cputime
);
3768 /* Add user time to cpustat. */
3769 tmp
= cputime_to_cputime64(cputime
);
3770 if (TASK_NICE(p
) > 0)
3771 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
3773 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
3775 cpuacct_update_stats(p
, CPUACCT_STAT_USER
, cputime
);
3776 /* Account for user time used */
3777 acct_update_integrals(p
);
3781 * Account guest cpu time to a process.
3782 * @p: the process that the cpu time gets accounted to
3783 * @cputime: the cpu time spent in virtual machine since the last update
3784 * @cputime_scaled: cputime scaled by cpu frequency
3786 static void account_guest_time(struct task_struct
*p
, cputime_t cputime
,
3787 cputime_t cputime_scaled
)
3790 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3792 tmp
= cputime_to_cputime64(cputime
);
3794 /* Add guest time to process. */
3795 p
->utime
= cputime_add(p
->utime
, cputime
);
3796 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
3797 account_group_user_time(p
, cputime
);
3798 p
->gtime
= cputime_add(p
->gtime
, cputime
);
3800 /* Add guest time to cpustat. */
3801 if (TASK_NICE(p
) > 0) {
3802 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
3803 cpustat
->guest_nice
= cputime64_add(cpustat
->guest_nice
, tmp
);
3805 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
3806 cpustat
->guest
= cputime64_add(cpustat
->guest
, tmp
);
3811 * Account system cpu time to a process and desired cpustat field
3812 * @p: the process that the cpu time gets accounted to
3813 * @cputime: the cpu time spent in kernel space since the last update
3814 * @cputime_scaled: cputime scaled by cpu frequency
3815 * @target_cputime64: pointer to cpustat field that has to be updated
3818 void __account_system_time(struct task_struct
*p
, cputime_t cputime
,
3819 cputime_t cputime_scaled
, cputime64_t
*target_cputime64
)
3821 cputime64_t tmp
= cputime_to_cputime64(cputime
);
3823 /* Add system time to process. */
3824 p
->stime
= cputime_add(p
->stime
, cputime
);
3825 p
->stimescaled
= cputime_add(p
->stimescaled
, cputime_scaled
);
3826 account_group_system_time(p
, cputime
);
3828 /* Add system time to cpustat. */
3829 *target_cputime64
= cputime64_add(*target_cputime64
, tmp
);
3830 cpuacct_update_stats(p
, CPUACCT_STAT_SYSTEM
, cputime
);
3832 /* Account for system time used */
3833 acct_update_integrals(p
);
3837 * Account system cpu time to a process.
3838 * @p: the process that the cpu time gets accounted to
3839 * @hardirq_offset: the offset to subtract from hardirq_count()
3840 * @cputime: the cpu time spent in kernel space since the last update
3841 * @cputime_scaled: cputime scaled by cpu frequency
3843 void account_system_time(struct task_struct
*p
, int hardirq_offset
,
3844 cputime_t cputime
, cputime_t cputime_scaled
)
3846 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3847 cputime64_t
*target_cputime64
;
3849 if ((p
->flags
& PF_VCPU
) && (irq_count() - hardirq_offset
== 0)) {
3850 account_guest_time(p
, cputime
, cputime_scaled
);
3854 if (hardirq_count() - hardirq_offset
)
3855 target_cputime64
= &cpustat
->irq
;
3856 else if (in_serving_softirq())
3857 target_cputime64
= &cpustat
->softirq
;
3859 target_cputime64
= &cpustat
->system
;
3861 __account_system_time(p
, cputime
, cputime_scaled
, target_cputime64
);
3865 * Account for involuntary wait time.
3866 * @cputime: the cpu time spent in involuntary wait
3868 void account_steal_time(cputime_t cputime
)
3870 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3871 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
3873 cpustat
->steal
= cputime64_add(cpustat
->steal
, cputime64
);
3877 * Account for idle time.
3878 * @cputime: the cpu time spent in idle wait
3880 void account_idle_time(cputime_t cputime
)
3882 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3883 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
3884 struct rq
*rq
= this_rq();
3886 if (atomic_read(&rq
->nr_iowait
) > 0)
3887 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, cputime64
);
3889 cpustat
->idle
= cputime64_add(cpustat
->idle
, cputime64
);
3892 static __always_inline
bool steal_account_process_tick(void)
3894 #ifdef CONFIG_PARAVIRT
3895 if (static_branch(¶virt_steal_enabled
)) {
3898 steal
= paravirt_steal_clock(smp_processor_id());
3899 steal
-= this_rq()->prev_steal_time
;
3901 st
= steal_ticks(steal
);
3902 this_rq()->prev_steal_time
+= st
* TICK_NSEC
;
3904 account_steal_time(st
);
3911 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
3913 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
3915 * Account a tick to a process and cpustat
3916 * @p: the process that the cpu time gets accounted to
3917 * @user_tick: is the tick from userspace
3918 * @rq: the pointer to rq
3920 * Tick demultiplexing follows the order
3921 * - pending hardirq update
3922 * - pending softirq update
3926 * - check for guest_time
3927 * - else account as system_time
3929 * Check for hardirq is done both for system and user time as there is
3930 * no timer going off while we are on hardirq and hence we may never get an
3931 * opportunity to update it solely in system time.
3932 * p->stime and friends are only updated on system time and not on irq
3933 * softirq as those do not count in task exec_runtime any more.
3935 static void irqtime_account_process_tick(struct task_struct
*p
, int user_tick
,
3938 cputime_t one_jiffy_scaled
= cputime_to_scaled(cputime_one_jiffy
);
3939 cputime64_t tmp
= cputime_to_cputime64(cputime_one_jiffy
);
3940 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3942 if (steal_account_process_tick())
3945 if (irqtime_account_hi_update()) {
3946 cpustat
->irq
= cputime64_add(cpustat
->irq
, tmp
);
3947 } else if (irqtime_account_si_update()) {
3948 cpustat
->softirq
= cputime64_add(cpustat
->softirq
, tmp
);
3949 } else if (this_cpu_ksoftirqd() == p
) {
3951 * ksoftirqd time do not get accounted in cpu_softirq_time.
3952 * So, we have to handle it separately here.
3953 * Also, p->stime needs to be updated for ksoftirqd.
3955 __account_system_time(p
, cputime_one_jiffy
, one_jiffy_scaled
,
3957 } else if (user_tick
) {
3958 account_user_time(p
, cputime_one_jiffy
, one_jiffy_scaled
);
3959 } else if (p
== rq
->idle
) {
3960 account_idle_time(cputime_one_jiffy
);
3961 } else if (p
->flags
& PF_VCPU
) { /* System time or guest time */
3962 account_guest_time(p
, cputime_one_jiffy
, one_jiffy_scaled
);
3964 __account_system_time(p
, cputime_one_jiffy
, one_jiffy_scaled
,
3969 static void irqtime_account_idle_ticks(int ticks
)
3972 struct rq
*rq
= this_rq();
3974 for (i
= 0; i
< ticks
; i
++)
3975 irqtime_account_process_tick(current
, 0, rq
);
3977 #else /* CONFIG_IRQ_TIME_ACCOUNTING */
3978 static void irqtime_account_idle_ticks(int ticks
) {}
3979 static void irqtime_account_process_tick(struct task_struct
*p
, int user_tick
,
3981 #endif /* CONFIG_IRQ_TIME_ACCOUNTING */
3984 * Account a single tick of cpu time.
3985 * @p: the process that the cpu time gets accounted to
3986 * @user_tick: indicates if the tick is a user or a system tick
3988 void account_process_tick(struct task_struct
*p
, int user_tick
)
3990 cputime_t one_jiffy_scaled
= cputime_to_scaled(cputime_one_jiffy
);
3991 struct rq
*rq
= this_rq();
3993 if (sched_clock_irqtime
) {
3994 irqtime_account_process_tick(p
, user_tick
, rq
);
3998 if (steal_account_process_tick())
4002 account_user_time(p
, cputime_one_jiffy
, one_jiffy_scaled
);
4003 else if ((p
!= rq
->idle
) || (irq_count() != HARDIRQ_OFFSET
))
4004 account_system_time(p
, HARDIRQ_OFFSET
, cputime_one_jiffy
,
4007 account_idle_time(cputime_one_jiffy
);
4011 * Account multiple ticks of steal time.
4012 * @p: the process from which the cpu time has been stolen
4013 * @ticks: number of stolen ticks
4015 void account_steal_ticks(unsigned long ticks
)
4017 account_steal_time(jiffies_to_cputime(ticks
));
4021 * Account multiple ticks of idle time.
4022 * @ticks: number of stolen ticks
4024 void account_idle_ticks(unsigned long ticks
)
4027 if (sched_clock_irqtime
) {
4028 irqtime_account_idle_ticks(ticks
);
4032 account_idle_time(jiffies_to_cputime(ticks
));
4038 * Use precise platform statistics if available:
4040 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
4041 void task_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
4047 void thread_group_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
4049 struct task_cputime cputime
;
4051 thread_group_cputime(p
, &cputime
);
4053 *ut
= cputime
.utime
;
4054 *st
= cputime
.stime
;
4058 #ifndef nsecs_to_cputime
4059 # define nsecs_to_cputime(__nsecs) nsecs_to_jiffies(__nsecs)
4062 void task_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
4064 cputime_t rtime
, utime
= p
->utime
, total
= cputime_add(utime
, p
->stime
);
4067 * Use CFS's precise accounting:
4069 rtime
= nsecs_to_cputime(p
->se
.sum_exec_runtime
);
4075 do_div(temp
, total
);
4076 utime
= (cputime_t
)temp
;
4081 * Compare with previous values, to keep monotonicity:
4083 p
->prev_utime
= max(p
->prev_utime
, utime
);
4084 p
->prev_stime
= max(p
->prev_stime
, cputime_sub(rtime
, p
->prev_utime
));
4086 *ut
= p
->prev_utime
;
4087 *st
= p
->prev_stime
;
4091 * Must be called with siglock held.
4093 void thread_group_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
4095 struct signal_struct
*sig
= p
->signal
;
4096 struct task_cputime cputime
;
4097 cputime_t rtime
, utime
, total
;
4099 thread_group_cputime(p
, &cputime
);
4101 total
= cputime_add(cputime
.utime
, cputime
.stime
);
4102 rtime
= nsecs_to_cputime(cputime
.sum_exec_runtime
);
4107 temp
*= cputime
.utime
;
4108 do_div(temp
, total
);
4109 utime
= (cputime_t
)temp
;
4113 sig
->prev_utime
= max(sig
->prev_utime
, utime
);
4114 sig
->prev_stime
= max(sig
->prev_stime
,
4115 cputime_sub(rtime
, sig
->prev_utime
));
4117 *ut
= sig
->prev_utime
;
4118 *st
= sig
->prev_stime
;
4123 * This function gets called by the timer code, with HZ frequency.
4124 * We call it with interrupts disabled.
4126 void scheduler_tick(void)
4128 int cpu
= smp_processor_id();
4129 struct rq
*rq
= cpu_rq(cpu
);
4130 struct task_struct
*curr
= rq
->curr
;
4134 raw_spin_lock(&rq
->lock
);
4135 update_rq_clock(rq
);
4136 update_cpu_load_active(rq
);
4137 curr
->sched_class
->task_tick(rq
, curr
, 0);
4138 raw_spin_unlock(&rq
->lock
);
4140 perf_event_task_tick();
4143 rq
->idle_at_tick
= idle_cpu(cpu
);
4144 trigger_load_balance(rq
, cpu
);
4148 notrace
unsigned long get_parent_ip(unsigned long addr
)
4150 if (in_lock_functions(addr
)) {
4151 addr
= CALLER_ADDR2
;
4152 if (in_lock_functions(addr
))
4153 addr
= CALLER_ADDR3
;
4158 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
4159 defined(CONFIG_PREEMPT_TRACER))
4161 void __kprobes
add_preempt_count(int val
)
4163 #ifdef CONFIG_DEBUG_PREEMPT
4167 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
4170 preempt_count() += val
;
4171 #ifdef CONFIG_DEBUG_PREEMPT
4173 * Spinlock count overflowing soon?
4175 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
4178 if (preempt_count() == val
)
4179 trace_preempt_off(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
4181 EXPORT_SYMBOL(add_preempt_count
);
4183 void __kprobes
sub_preempt_count(int val
)
4185 #ifdef CONFIG_DEBUG_PREEMPT
4189 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
4192 * Is the spinlock portion underflowing?
4194 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
4195 !(preempt_count() & PREEMPT_MASK
)))
4199 if (preempt_count() == val
)
4200 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
4201 preempt_count() -= val
;
4203 EXPORT_SYMBOL(sub_preempt_count
);
4208 * Print scheduling while atomic bug:
4210 static noinline
void __schedule_bug(struct task_struct
*prev
)
4212 struct pt_regs
*regs
= get_irq_regs();
4214 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
4215 prev
->comm
, prev
->pid
, preempt_count());
4217 debug_show_held_locks(prev
);
4219 if (irqs_disabled())
4220 print_irqtrace_events(prev
);
4229 * Various schedule()-time debugging checks and statistics:
4231 static inline void schedule_debug(struct task_struct
*prev
)
4234 * Test if we are atomic. Since do_exit() needs to call into
4235 * schedule() atomically, we ignore that path for now.
4236 * Otherwise, whine if we are scheduling when we should not be.
4238 if (unlikely(in_atomic_preempt_off() && !prev
->exit_state
))
4239 __schedule_bug(prev
);
4241 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
4243 schedstat_inc(this_rq(), sched_count
);
4246 static void put_prev_task(struct rq
*rq
, struct task_struct
*prev
)
4248 if (prev
->on_rq
|| rq
->skip_clock_update
< 0)
4249 update_rq_clock(rq
);
4250 prev
->sched_class
->put_prev_task(rq
, prev
);
4254 * Pick up the highest-prio task:
4256 static inline struct task_struct
*
4257 pick_next_task(struct rq
*rq
)
4259 const struct sched_class
*class;
4260 struct task_struct
*p
;
4263 * Optimization: we know that if all tasks are in
4264 * the fair class we can call that function directly:
4266 if (likely(rq
->nr_running
== rq
->cfs
.nr_running
)) {
4267 p
= fair_sched_class
.pick_next_task(rq
);
4272 for_each_class(class) {
4273 p
= class->pick_next_task(rq
);
4278 BUG(); /* the idle class will always have a runnable task */
4282 * schedule() is the main scheduler function.
4284 asmlinkage
void __sched
schedule(void)
4286 struct task_struct
*prev
, *next
;
4287 unsigned long *switch_count
;
4293 cpu
= smp_processor_id();
4295 rcu_note_context_switch(cpu
);
4298 schedule_debug(prev
);
4300 if (sched_feat(HRTICK
))
4303 raw_spin_lock_irq(&rq
->lock
);
4305 switch_count
= &prev
->nivcsw
;
4306 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
4307 if (unlikely(signal_pending_state(prev
->state
, prev
))) {
4308 prev
->state
= TASK_RUNNING
;
4310 deactivate_task(rq
, prev
, DEQUEUE_SLEEP
);
4314 * If a worker went to sleep, notify and ask workqueue
4315 * whether it wants to wake up a task to maintain
4318 if (prev
->flags
& PF_WQ_WORKER
) {
4319 struct task_struct
*to_wakeup
;
4321 to_wakeup
= wq_worker_sleeping(prev
, cpu
);
4323 try_to_wake_up_local(to_wakeup
);
4327 * If we are going to sleep and we have plugged IO
4328 * queued, make sure to submit it to avoid deadlocks.
4330 if (blk_needs_flush_plug(prev
)) {
4331 raw_spin_unlock(&rq
->lock
);
4332 blk_schedule_flush_plug(prev
);
4333 raw_spin_lock(&rq
->lock
);
4336 switch_count
= &prev
->nvcsw
;
4339 pre_schedule(rq
, prev
);
4341 if (unlikely(!rq
->nr_running
))
4342 idle_balance(cpu
, rq
);
4344 put_prev_task(rq
, prev
);
4345 next
= pick_next_task(rq
);
4346 clear_tsk_need_resched(prev
);
4347 rq
->skip_clock_update
= 0;
4349 if (likely(prev
!= next
)) {
4354 context_switch(rq
, prev
, next
); /* unlocks the rq */
4356 * The context switch have flipped the stack from under us
4357 * and restored the local variables which were saved when
4358 * this task called schedule() in the past. prev == current
4359 * is still correct, but it can be moved to another cpu/rq.
4361 cpu
= smp_processor_id();
4364 raw_spin_unlock_irq(&rq
->lock
);
4368 preempt_enable_no_resched();
4372 EXPORT_SYMBOL(schedule
);
4374 #ifdef CONFIG_MUTEX_SPIN_ON_OWNER
4376 static inline bool owner_running(struct mutex
*lock
, struct task_struct
*owner
)
4378 if (lock
->owner
!= owner
)
4382 * Ensure we emit the owner->on_cpu, dereference _after_ checking
4383 * lock->owner still matches owner, if that fails, owner might
4384 * point to free()d memory, if it still matches, the rcu_read_lock()
4385 * ensures the memory stays valid.
4389 return owner
->on_cpu
;
4393 * Look out! "owner" is an entirely speculative pointer
4394 * access and not reliable.
4396 int mutex_spin_on_owner(struct mutex
*lock
, struct task_struct
*owner
)
4398 if (!sched_feat(OWNER_SPIN
))
4402 while (owner_running(lock
, owner
)) {
4406 arch_mutex_cpu_relax();
4411 * We break out the loop above on need_resched() and when the
4412 * owner changed, which is a sign for heavy contention. Return
4413 * success only when lock->owner is NULL.
4415 return lock
->owner
== NULL
;
4419 #ifdef CONFIG_PREEMPT
4421 * this is the entry point to schedule() from in-kernel preemption
4422 * off of preempt_enable. Kernel preemptions off return from interrupt
4423 * occur there and call schedule directly.
4425 asmlinkage
void __sched notrace
preempt_schedule(void)
4427 struct thread_info
*ti
= current_thread_info();
4430 * If there is a non-zero preempt_count or interrupts are disabled,
4431 * we do not want to preempt the current task. Just return..
4433 if (likely(ti
->preempt_count
|| irqs_disabled()))
4437 add_preempt_count_notrace(PREEMPT_ACTIVE
);
4439 sub_preempt_count_notrace(PREEMPT_ACTIVE
);
4442 * Check again in case we missed a preemption opportunity
4443 * between schedule and now.
4446 } while (need_resched());
4448 EXPORT_SYMBOL(preempt_schedule
);
4451 * this is the entry point to schedule() from kernel preemption
4452 * off of irq context.
4453 * Note, that this is called and return with irqs disabled. This will
4454 * protect us against recursive calling from irq.
4456 asmlinkage
void __sched
preempt_schedule_irq(void)
4458 struct thread_info
*ti
= current_thread_info();
4460 /* Catch callers which need to be fixed */
4461 BUG_ON(ti
->preempt_count
|| !irqs_disabled());
4464 add_preempt_count(PREEMPT_ACTIVE
);
4467 local_irq_disable();
4468 sub_preempt_count(PREEMPT_ACTIVE
);
4471 * Check again in case we missed a preemption opportunity
4472 * between schedule and now.
4475 } while (need_resched());
4478 #endif /* CONFIG_PREEMPT */
4480 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int wake_flags
,
4483 return try_to_wake_up(curr
->private, mode
, wake_flags
);
4485 EXPORT_SYMBOL(default_wake_function
);
4488 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
4489 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
4490 * number) then we wake all the non-exclusive tasks and one exclusive task.
4492 * There are circumstances in which we can try to wake a task which has already
4493 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
4494 * zero in this (rare) case, and we handle it by continuing to scan the queue.
4496 static void __wake_up_common(wait_queue_head_t
*q
, unsigned int mode
,
4497 int nr_exclusive
, int wake_flags
, void *key
)
4499 wait_queue_t
*curr
, *next
;
4501 list_for_each_entry_safe(curr
, next
, &q
->task_list
, task_list
) {
4502 unsigned flags
= curr
->flags
;
4504 if (curr
->func(curr
, mode
, wake_flags
, key
) &&
4505 (flags
& WQ_FLAG_EXCLUSIVE
) && !--nr_exclusive
)
4511 * __wake_up - wake up threads blocked on a waitqueue.
4513 * @mode: which threads
4514 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4515 * @key: is directly passed to the wakeup function
4517 * It may be assumed that this function implies a write memory barrier before
4518 * changing the task state if and only if any tasks are woken up.
4520 void __wake_up(wait_queue_head_t
*q
, unsigned int mode
,
4521 int nr_exclusive
, void *key
)
4523 unsigned long flags
;
4525 spin_lock_irqsave(&q
->lock
, flags
);
4526 __wake_up_common(q
, mode
, nr_exclusive
, 0, key
);
4527 spin_unlock_irqrestore(&q
->lock
, flags
);
4529 EXPORT_SYMBOL(__wake_up
);
4532 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
4534 void __wake_up_locked(wait_queue_head_t
*q
, unsigned int mode
)
4536 __wake_up_common(q
, mode
, 1, 0, NULL
);
4538 EXPORT_SYMBOL_GPL(__wake_up_locked
);
4540 void __wake_up_locked_key(wait_queue_head_t
*q
, unsigned int mode
, void *key
)
4542 __wake_up_common(q
, mode
, 1, 0, key
);
4544 EXPORT_SYMBOL_GPL(__wake_up_locked_key
);
4547 * __wake_up_sync_key - wake up threads blocked on a waitqueue.
4549 * @mode: which threads
4550 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4551 * @key: opaque value to be passed to wakeup targets
4553 * The sync wakeup differs that the waker knows that it will schedule
4554 * away soon, so while the target thread will be woken up, it will not
4555 * be migrated to another CPU - ie. the two threads are 'synchronized'
4556 * with each other. This can prevent needless bouncing between CPUs.
4558 * On UP it can prevent extra preemption.
4560 * It may be assumed that this function implies a write memory barrier before
4561 * changing the task state if and only if any tasks are woken up.
4563 void __wake_up_sync_key(wait_queue_head_t
*q
, unsigned int mode
,
4564 int nr_exclusive
, void *key
)
4566 unsigned long flags
;
4567 int wake_flags
= WF_SYNC
;
4572 if (unlikely(!nr_exclusive
))
4575 spin_lock_irqsave(&q
->lock
, flags
);
4576 __wake_up_common(q
, mode
, nr_exclusive
, wake_flags
, key
);
4577 spin_unlock_irqrestore(&q
->lock
, flags
);
4579 EXPORT_SYMBOL_GPL(__wake_up_sync_key
);
4582 * __wake_up_sync - see __wake_up_sync_key()
4584 void __wake_up_sync(wait_queue_head_t
*q
, unsigned int mode
, int nr_exclusive
)
4586 __wake_up_sync_key(q
, mode
, nr_exclusive
, NULL
);
4588 EXPORT_SYMBOL_GPL(__wake_up_sync
); /* For internal use only */
4591 * complete: - signals a single thread waiting on this completion
4592 * @x: holds the state of this particular completion
4594 * This will wake up a single thread waiting on this completion. Threads will be
4595 * awakened in the same order in which they were queued.
4597 * See also complete_all(), wait_for_completion() and related routines.
4599 * It may be assumed that this function implies a write memory barrier before
4600 * changing the task state if and only if any tasks are woken up.
4602 void complete(struct completion
*x
)
4604 unsigned long flags
;
4606 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4608 __wake_up_common(&x
->wait
, TASK_NORMAL
, 1, 0, NULL
);
4609 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4611 EXPORT_SYMBOL(complete
);
4614 * complete_all: - signals all threads waiting on this completion
4615 * @x: holds the state of this particular completion
4617 * This will wake up all threads waiting on this particular completion event.
4619 * It may be assumed that this function implies a write memory barrier before
4620 * changing the task state if and only if any tasks are woken up.
4622 void complete_all(struct completion
*x
)
4624 unsigned long flags
;
4626 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4627 x
->done
+= UINT_MAX
/2;
4628 __wake_up_common(&x
->wait
, TASK_NORMAL
, 0, 0, NULL
);
4629 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4631 EXPORT_SYMBOL(complete_all
);
4633 static inline long __sched
4634 do_wait_for_common(struct completion
*x
, long timeout
, int state
)
4637 DECLARE_WAITQUEUE(wait
, current
);
4639 __add_wait_queue_tail_exclusive(&x
->wait
, &wait
);
4641 if (signal_pending_state(state
, current
)) {
4642 timeout
= -ERESTARTSYS
;
4645 __set_current_state(state
);
4646 spin_unlock_irq(&x
->wait
.lock
);
4647 timeout
= schedule_timeout(timeout
);
4648 spin_lock_irq(&x
->wait
.lock
);
4649 } while (!x
->done
&& timeout
);
4650 __remove_wait_queue(&x
->wait
, &wait
);
4655 return timeout
?: 1;
4659 wait_for_common(struct completion
*x
, long timeout
, int state
)
4663 spin_lock_irq(&x
->wait
.lock
);
4664 timeout
= do_wait_for_common(x
, timeout
, state
);
4665 spin_unlock_irq(&x
->wait
.lock
);
4670 * wait_for_completion: - waits for completion of a task
4671 * @x: holds the state of this particular completion
4673 * This waits to be signaled for completion of a specific task. It is NOT
4674 * interruptible and there is no timeout.
4676 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
4677 * and interrupt capability. Also see complete().
4679 void __sched
wait_for_completion(struct completion
*x
)
4681 wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
4683 EXPORT_SYMBOL(wait_for_completion
);
4686 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
4687 * @x: holds the state of this particular completion
4688 * @timeout: timeout value in jiffies
4690 * This waits for either a completion of a specific task to be signaled or for a
4691 * specified timeout to expire. The timeout is in jiffies. It is not
4694 unsigned long __sched
4695 wait_for_completion_timeout(struct completion
*x
, unsigned long timeout
)
4697 return wait_for_common(x
, timeout
, TASK_UNINTERRUPTIBLE
);
4699 EXPORT_SYMBOL(wait_for_completion_timeout
);
4702 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
4703 * @x: holds the state of this particular completion
4705 * This waits for completion of a specific task to be signaled. It is
4708 int __sched
wait_for_completion_interruptible(struct completion
*x
)
4710 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_INTERRUPTIBLE
);
4711 if (t
== -ERESTARTSYS
)
4715 EXPORT_SYMBOL(wait_for_completion_interruptible
);
4718 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
4719 * @x: holds the state of this particular completion
4720 * @timeout: timeout value in jiffies
4722 * This waits for either a completion of a specific task to be signaled or for a
4723 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
4726 wait_for_completion_interruptible_timeout(struct completion
*x
,
4727 unsigned long timeout
)
4729 return wait_for_common(x
, timeout
, TASK_INTERRUPTIBLE
);
4731 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout
);
4734 * wait_for_completion_killable: - waits for completion of a task (killable)
4735 * @x: holds the state of this particular completion
4737 * This waits to be signaled for completion of a specific task. It can be
4738 * interrupted by a kill signal.
4740 int __sched
wait_for_completion_killable(struct completion
*x
)
4742 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_KILLABLE
);
4743 if (t
== -ERESTARTSYS
)
4747 EXPORT_SYMBOL(wait_for_completion_killable
);
4750 * wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable))
4751 * @x: holds the state of this particular completion
4752 * @timeout: timeout value in jiffies
4754 * This waits for either a completion of a specific task to be
4755 * signaled or for a specified timeout to expire. It can be
4756 * interrupted by a kill signal. The timeout is in jiffies.
4759 wait_for_completion_killable_timeout(struct completion
*x
,
4760 unsigned long timeout
)
4762 return wait_for_common(x
, timeout
, TASK_KILLABLE
);
4764 EXPORT_SYMBOL(wait_for_completion_killable_timeout
);
4767 * try_wait_for_completion - try to decrement a completion without blocking
4768 * @x: completion structure
4770 * Returns: 0 if a decrement cannot be done without blocking
4771 * 1 if a decrement succeeded.
4773 * If a completion is being used as a counting completion,
4774 * attempt to decrement the counter without blocking. This
4775 * enables us to avoid waiting if the resource the completion
4776 * is protecting is not available.
4778 bool try_wait_for_completion(struct completion
*x
)
4780 unsigned long flags
;
4783 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4788 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4791 EXPORT_SYMBOL(try_wait_for_completion
);
4794 * completion_done - Test to see if a completion has any waiters
4795 * @x: completion structure
4797 * Returns: 0 if there are waiters (wait_for_completion() in progress)
4798 * 1 if there are no waiters.
4801 bool completion_done(struct completion
*x
)
4803 unsigned long flags
;
4806 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4809 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4812 EXPORT_SYMBOL(completion_done
);
4815 sleep_on_common(wait_queue_head_t
*q
, int state
, long timeout
)
4817 unsigned long flags
;
4820 init_waitqueue_entry(&wait
, current
);
4822 __set_current_state(state
);
4824 spin_lock_irqsave(&q
->lock
, flags
);
4825 __add_wait_queue(q
, &wait
);
4826 spin_unlock(&q
->lock
);
4827 timeout
= schedule_timeout(timeout
);
4828 spin_lock_irq(&q
->lock
);
4829 __remove_wait_queue(q
, &wait
);
4830 spin_unlock_irqrestore(&q
->lock
, flags
);
4835 void __sched
interruptible_sleep_on(wait_queue_head_t
*q
)
4837 sleep_on_common(q
, TASK_INTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
4839 EXPORT_SYMBOL(interruptible_sleep_on
);
4842 interruptible_sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
4844 return sleep_on_common(q
, TASK_INTERRUPTIBLE
, timeout
);
4846 EXPORT_SYMBOL(interruptible_sleep_on_timeout
);
4848 void __sched
sleep_on(wait_queue_head_t
*q
)
4850 sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
4852 EXPORT_SYMBOL(sleep_on
);
4854 long __sched
sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
4856 return sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, timeout
);
4858 EXPORT_SYMBOL(sleep_on_timeout
);
4860 #ifdef CONFIG_RT_MUTEXES
4863 * rt_mutex_setprio - set the current priority of a task
4865 * @prio: prio value (kernel-internal form)
4867 * This function changes the 'effective' priority of a task. It does
4868 * not touch ->normal_prio like __setscheduler().
4870 * Used by the rt_mutex code to implement priority inheritance logic.
4872 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
4874 int oldprio
, on_rq
, running
;
4876 const struct sched_class
*prev_class
;
4878 BUG_ON(prio
< 0 || prio
> MAX_PRIO
);
4880 rq
= __task_rq_lock(p
);
4882 trace_sched_pi_setprio(p
, prio
);
4884 prev_class
= p
->sched_class
;
4886 running
= task_current(rq
, p
);
4888 dequeue_task(rq
, p
, 0);
4890 p
->sched_class
->put_prev_task(rq
, p
);
4893 p
->sched_class
= &rt_sched_class
;
4895 p
->sched_class
= &fair_sched_class
;
4900 p
->sched_class
->set_curr_task(rq
);
4902 enqueue_task(rq
, p
, oldprio
< prio
? ENQUEUE_HEAD
: 0);
4904 check_class_changed(rq
, p
, prev_class
, oldprio
);
4905 __task_rq_unlock(rq
);
4910 void set_user_nice(struct task_struct
*p
, long nice
)
4912 int old_prio
, delta
, on_rq
;
4913 unsigned long flags
;
4916 if (TASK_NICE(p
) == nice
|| nice
< -20 || nice
> 19)
4919 * We have to be careful, if called from sys_setpriority(),
4920 * the task might be in the middle of scheduling on another CPU.
4922 rq
= task_rq_lock(p
, &flags
);
4924 * The RT priorities are set via sched_setscheduler(), but we still
4925 * allow the 'normal' nice value to be set - but as expected
4926 * it wont have any effect on scheduling until the task is
4927 * SCHED_FIFO/SCHED_RR:
4929 if (task_has_rt_policy(p
)) {
4930 p
->static_prio
= NICE_TO_PRIO(nice
);
4935 dequeue_task(rq
, p
, 0);
4937 p
->static_prio
= NICE_TO_PRIO(nice
);
4940 p
->prio
= effective_prio(p
);
4941 delta
= p
->prio
- old_prio
;
4944 enqueue_task(rq
, p
, 0);
4946 * If the task increased its priority or is running and
4947 * lowered its priority, then reschedule its CPU:
4949 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
4950 resched_task(rq
->curr
);
4953 task_rq_unlock(rq
, p
, &flags
);
4955 EXPORT_SYMBOL(set_user_nice
);
4958 * can_nice - check if a task can reduce its nice value
4962 int can_nice(const struct task_struct
*p
, const int nice
)
4964 /* convert nice value [19,-20] to rlimit style value [1,40] */
4965 int nice_rlim
= 20 - nice
;
4967 return (nice_rlim
<= task_rlimit(p
, RLIMIT_NICE
) ||
4968 capable(CAP_SYS_NICE
));
4971 #ifdef __ARCH_WANT_SYS_NICE
4974 * sys_nice - change the priority of the current process.
4975 * @increment: priority increment
4977 * sys_setpriority is a more generic, but much slower function that
4978 * does similar things.
4980 SYSCALL_DEFINE1(nice
, int, increment
)
4985 * Setpriority might change our priority at the same moment.
4986 * We don't have to worry. Conceptually one call occurs first
4987 * and we have a single winner.
4989 if (increment
< -40)
4994 nice
= TASK_NICE(current
) + increment
;
5000 if (increment
< 0 && !can_nice(current
, nice
))
5003 retval
= security_task_setnice(current
, nice
);
5007 set_user_nice(current
, nice
);
5014 * task_prio - return the priority value of a given task.
5015 * @p: the task in question.
5017 * This is the priority value as seen by users in /proc.
5018 * RT tasks are offset by -200. Normal tasks are centered
5019 * around 0, value goes from -16 to +15.
5021 int task_prio(const struct task_struct
*p
)
5023 return p
->prio
- MAX_RT_PRIO
;
5027 * task_nice - return the nice value of a given task.
5028 * @p: the task in question.
5030 int task_nice(const struct task_struct
*p
)
5032 return TASK_NICE(p
);
5034 EXPORT_SYMBOL(task_nice
);
5037 * idle_cpu - is a given cpu idle currently?
5038 * @cpu: the processor in question.
5040 int idle_cpu(int cpu
)
5042 return cpu_curr(cpu
) == cpu_rq(cpu
)->idle
;
5046 * idle_task - return the idle task for a given cpu.
5047 * @cpu: the processor in question.
5049 struct task_struct
*idle_task(int cpu
)
5051 return cpu_rq(cpu
)->idle
;
5055 * find_process_by_pid - find a process with a matching PID value.
5056 * @pid: the pid in question.
5058 static struct task_struct
*find_process_by_pid(pid_t pid
)
5060 return pid
? find_task_by_vpid(pid
) : current
;
5063 /* Actually do priority change: must hold rq lock. */
5065 __setscheduler(struct rq
*rq
, struct task_struct
*p
, int policy
, int prio
)
5068 p
->rt_priority
= prio
;
5069 p
->normal_prio
= normal_prio(p
);
5070 /* we are holding p->pi_lock already */
5071 p
->prio
= rt_mutex_getprio(p
);
5072 if (rt_prio(p
->prio
))
5073 p
->sched_class
= &rt_sched_class
;
5075 p
->sched_class
= &fair_sched_class
;
5080 * check the target process has a UID that matches the current process's
5082 static bool check_same_owner(struct task_struct
*p
)
5084 const struct cred
*cred
= current_cred(), *pcred
;
5088 pcred
= __task_cred(p
);
5089 if (cred
->user
->user_ns
== pcred
->user
->user_ns
)
5090 match
= (cred
->euid
== pcred
->euid
||
5091 cred
->euid
== pcred
->uid
);
5098 static int __sched_setscheduler(struct task_struct
*p
, int policy
,
5099 const struct sched_param
*param
, bool user
)
5101 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
5102 unsigned long flags
;
5103 const struct sched_class
*prev_class
;
5107 /* may grab non-irq protected spin_locks */
5108 BUG_ON(in_interrupt());
5110 /* double check policy once rq lock held */
5112 reset_on_fork
= p
->sched_reset_on_fork
;
5113 policy
= oldpolicy
= p
->policy
;
5115 reset_on_fork
= !!(policy
& SCHED_RESET_ON_FORK
);
5116 policy
&= ~SCHED_RESET_ON_FORK
;
5118 if (policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
5119 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
5120 policy
!= SCHED_IDLE
)
5125 * Valid priorities for SCHED_FIFO and SCHED_RR are
5126 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
5127 * SCHED_BATCH and SCHED_IDLE is 0.
5129 if (param
->sched_priority
< 0 ||
5130 (p
->mm
&& param
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
5131 (!p
->mm
&& param
->sched_priority
> MAX_RT_PRIO
-1))
5133 if (rt_policy(policy
) != (param
->sched_priority
!= 0))
5137 * Allow unprivileged RT tasks to decrease priority:
5139 if (user
&& !capable(CAP_SYS_NICE
)) {
5140 if (rt_policy(policy
)) {
5141 unsigned long rlim_rtprio
=
5142 task_rlimit(p
, RLIMIT_RTPRIO
);
5144 /* can't set/change the rt policy */
5145 if (policy
!= p
->policy
&& !rlim_rtprio
)
5148 /* can't increase priority */
5149 if (param
->sched_priority
> p
->rt_priority
&&
5150 param
->sched_priority
> rlim_rtprio
)
5155 * Treat SCHED_IDLE as nice 20. Only allow a switch to
5156 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
5158 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
) {
5159 if (!can_nice(p
, TASK_NICE(p
)))
5163 /* can't change other user's priorities */
5164 if (!check_same_owner(p
))
5167 /* Normal users shall not reset the sched_reset_on_fork flag */
5168 if (p
->sched_reset_on_fork
&& !reset_on_fork
)
5173 retval
= security_task_setscheduler(p
);
5179 * make sure no PI-waiters arrive (or leave) while we are
5180 * changing the priority of the task:
5182 * To be able to change p->policy safely, the appropriate
5183 * runqueue lock must be held.
5185 rq
= task_rq_lock(p
, &flags
);
5188 * Changing the policy of the stop threads its a very bad idea
5190 if (p
== rq
->stop
) {
5191 task_rq_unlock(rq
, p
, &flags
);
5196 * If not changing anything there's no need to proceed further:
5198 if (unlikely(policy
== p
->policy
&& (!rt_policy(policy
) ||
5199 param
->sched_priority
== p
->rt_priority
))) {
5201 __task_rq_unlock(rq
);
5202 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
5206 #ifdef CONFIG_RT_GROUP_SCHED
5209 * Do not allow realtime tasks into groups that have no runtime
5212 if (rt_bandwidth_enabled() && rt_policy(policy
) &&
5213 task_group(p
)->rt_bandwidth
.rt_runtime
== 0 &&
5214 !task_group_is_autogroup(task_group(p
))) {
5215 task_rq_unlock(rq
, p
, &flags
);
5221 /* recheck policy now with rq lock held */
5222 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
5223 policy
= oldpolicy
= -1;
5224 task_rq_unlock(rq
, p
, &flags
);
5228 running
= task_current(rq
, p
);
5230 deactivate_task(rq
, p
, 0);
5232 p
->sched_class
->put_prev_task(rq
, p
);
5234 p
->sched_reset_on_fork
= reset_on_fork
;
5237 prev_class
= p
->sched_class
;
5238 __setscheduler(rq
, p
, policy
, param
->sched_priority
);
5241 p
->sched_class
->set_curr_task(rq
);
5243 activate_task(rq
, p
, 0);
5245 check_class_changed(rq
, p
, prev_class
, oldprio
);
5246 task_rq_unlock(rq
, p
, &flags
);
5248 rt_mutex_adjust_pi(p
);
5254 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
5255 * @p: the task in question.
5256 * @policy: new policy.
5257 * @param: structure containing the new RT priority.
5259 * NOTE that the task may be already dead.
5261 int sched_setscheduler(struct task_struct
*p
, int policy
,
5262 const struct sched_param
*param
)
5264 return __sched_setscheduler(p
, policy
, param
, true);
5266 EXPORT_SYMBOL_GPL(sched_setscheduler
);
5269 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
5270 * @p: the task in question.
5271 * @policy: new policy.
5272 * @param: structure containing the new RT priority.
5274 * Just like sched_setscheduler, only don't bother checking if the
5275 * current context has permission. For example, this is needed in
5276 * stop_machine(): we create temporary high priority worker threads,
5277 * but our caller might not have that capability.
5279 int sched_setscheduler_nocheck(struct task_struct
*p
, int policy
,
5280 const struct sched_param
*param
)
5282 return __sched_setscheduler(p
, policy
, param
, false);
5286 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
5288 struct sched_param lparam
;
5289 struct task_struct
*p
;
5292 if (!param
|| pid
< 0)
5294 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
5299 p
= find_process_by_pid(pid
);
5301 retval
= sched_setscheduler(p
, policy
, &lparam
);
5308 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
5309 * @pid: the pid in question.
5310 * @policy: new policy.
5311 * @param: structure containing the new RT priority.
5313 SYSCALL_DEFINE3(sched_setscheduler
, pid_t
, pid
, int, policy
,
5314 struct sched_param __user
*, param
)
5316 /* negative values for policy are not valid */
5320 return do_sched_setscheduler(pid
, policy
, param
);
5324 * sys_sched_setparam - set/change the RT priority of a thread
5325 * @pid: the pid in question.
5326 * @param: structure containing the new RT priority.
5328 SYSCALL_DEFINE2(sched_setparam
, pid_t
, pid
, struct sched_param __user
*, param
)
5330 return do_sched_setscheduler(pid
, -1, param
);
5334 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
5335 * @pid: the pid in question.
5337 SYSCALL_DEFINE1(sched_getscheduler
, pid_t
, pid
)
5339 struct task_struct
*p
;
5347 p
= find_process_by_pid(pid
);
5349 retval
= security_task_getscheduler(p
);
5352 | (p
->sched_reset_on_fork
? SCHED_RESET_ON_FORK
: 0);
5359 * sys_sched_getparam - get the RT priority of a thread
5360 * @pid: the pid in question.
5361 * @param: structure containing the RT priority.
5363 SYSCALL_DEFINE2(sched_getparam
, pid_t
, pid
, struct sched_param __user
*, param
)
5365 struct sched_param lp
;
5366 struct task_struct
*p
;
5369 if (!param
|| pid
< 0)
5373 p
= find_process_by_pid(pid
);
5378 retval
= security_task_getscheduler(p
);
5382 lp
.sched_priority
= p
->rt_priority
;
5386 * This one might sleep, we cannot do it with a spinlock held ...
5388 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
5397 long sched_setaffinity(pid_t pid
, const struct cpumask
*in_mask
)
5399 cpumask_var_t cpus_allowed
, new_mask
;
5400 struct task_struct
*p
;
5406 p
= find_process_by_pid(pid
);
5413 /* Prevent p going away */
5417 if (!alloc_cpumask_var(&cpus_allowed
, GFP_KERNEL
)) {
5421 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
)) {
5423 goto out_free_cpus_allowed
;
5426 if (!check_same_owner(p
) && !task_ns_capable(p
, CAP_SYS_NICE
))
5429 retval
= security_task_setscheduler(p
);
5433 cpuset_cpus_allowed(p
, cpus_allowed
);
5434 cpumask_and(new_mask
, in_mask
, cpus_allowed
);
5436 retval
= set_cpus_allowed_ptr(p
, new_mask
);
5439 cpuset_cpus_allowed(p
, cpus_allowed
);
5440 if (!cpumask_subset(new_mask
, cpus_allowed
)) {
5442 * We must have raced with a concurrent cpuset
5443 * update. Just reset the cpus_allowed to the
5444 * cpuset's cpus_allowed
5446 cpumask_copy(new_mask
, cpus_allowed
);
5451 free_cpumask_var(new_mask
);
5452 out_free_cpus_allowed
:
5453 free_cpumask_var(cpus_allowed
);
5460 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
5461 struct cpumask
*new_mask
)
5463 if (len
< cpumask_size())
5464 cpumask_clear(new_mask
);
5465 else if (len
> cpumask_size())
5466 len
= cpumask_size();
5468 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
5472 * sys_sched_setaffinity - set the cpu affinity of a process
5473 * @pid: pid of the process
5474 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5475 * @user_mask_ptr: user-space pointer to the new cpu mask
5477 SYSCALL_DEFINE3(sched_setaffinity
, pid_t
, pid
, unsigned int, len
,
5478 unsigned long __user
*, user_mask_ptr
)
5480 cpumask_var_t new_mask
;
5483 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
5486 retval
= get_user_cpu_mask(user_mask_ptr
, len
, new_mask
);
5488 retval
= sched_setaffinity(pid
, new_mask
);
5489 free_cpumask_var(new_mask
);
5493 long sched_getaffinity(pid_t pid
, struct cpumask
*mask
)
5495 struct task_struct
*p
;
5496 unsigned long flags
;
5503 p
= find_process_by_pid(pid
);
5507 retval
= security_task_getscheduler(p
);
5511 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
5512 cpumask_and(mask
, &p
->cpus_allowed
, cpu_online_mask
);
5513 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
5523 * sys_sched_getaffinity - get the cpu affinity of a process
5524 * @pid: pid of the process
5525 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5526 * @user_mask_ptr: user-space pointer to hold the current cpu mask
5528 SYSCALL_DEFINE3(sched_getaffinity
, pid_t
, pid
, unsigned int, len
,
5529 unsigned long __user
*, user_mask_ptr
)
5534 if ((len
* BITS_PER_BYTE
) < nr_cpu_ids
)
5536 if (len
& (sizeof(unsigned long)-1))
5539 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
5542 ret
= sched_getaffinity(pid
, mask
);
5544 size_t retlen
= min_t(size_t, len
, cpumask_size());
5546 if (copy_to_user(user_mask_ptr
, mask
, retlen
))
5551 free_cpumask_var(mask
);
5557 * sys_sched_yield - yield the current processor to other threads.
5559 * This function yields the current CPU to other tasks. If there are no
5560 * other threads running on this CPU then this function will return.
5562 SYSCALL_DEFINE0(sched_yield
)
5564 struct rq
*rq
= this_rq_lock();
5566 schedstat_inc(rq
, yld_count
);
5567 current
->sched_class
->yield_task(rq
);
5570 * Since we are going to call schedule() anyway, there's
5571 * no need to preempt or enable interrupts:
5573 __release(rq
->lock
);
5574 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
5575 do_raw_spin_unlock(&rq
->lock
);
5576 preempt_enable_no_resched();
5583 static inline int should_resched(void)
5585 return need_resched() && !(preempt_count() & PREEMPT_ACTIVE
);
5588 static void __cond_resched(void)
5590 add_preempt_count(PREEMPT_ACTIVE
);
5592 sub_preempt_count(PREEMPT_ACTIVE
);
5595 int __sched
_cond_resched(void)
5597 if (should_resched()) {
5603 EXPORT_SYMBOL(_cond_resched
);
5606 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
5607 * call schedule, and on return reacquire the lock.
5609 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
5610 * operations here to prevent schedule() from being called twice (once via
5611 * spin_unlock(), once by hand).
5613 int __cond_resched_lock(spinlock_t
*lock
)
5615 int resched
= should_resched();
5618 lockdep_assert_held(lock
);
5620 if (spin_needbreak(lock
) || resched
) {
5631 EXPORT_SYMBOL(__cond_resched_lock
);
5633 int __sched
__cond_resched_softirq(void)
5635 BUG_ON(!in_softirq());
5637 if (should_resched()) {
5645 EXPORT_SYMBOL(__cond_resched_softirq
);
5648 * yield - yield the current processor to other threads.
5650 * This is a shortcut for kernel-space yielding - it marks the
5651 * thread runnable and calls sys_sched_yield().
5653 void __sched
yield(void)
5655 set_current_state(TASK_RUNNING
);
5658 EXPORT_SYMBOL(yield
);
5661 * yield_to - yield the current processor to another thread in
5662 * your thread group, or accelerate that thread toward the
5663 * processor it's on.
5665 * @preempt: whether task preemption is allowed or not
5667 * It's the caller's job to ensure that the target task struct
5668 * can't go away on us before we can do any checks.
5670 * Returns true if we indeed boosted the target task.
5672 bool __sched
yield_to(struct task_struct
*p
, bool preempt
)
5674 struct task_struct
*curr
= current
;
5675 struct rq
*rq
, *p_rq
;
5676 unsigned long flags
;
5679 local_irq_save(flags
);
5684 double_rq_lock(rq
, p_rq
);
5685 while (task_rq(p
) != p_rq
) {
5686 double_rq_unlock(rq
, p_rq
);
5690 if (!curr
->sched_class
->yield_to_task
)
5693 if (curr
->sched_class
!= p
->sched_class
)
5696 if (task_running(p_rq
, p
) || p
->state
)
5699 yielded
= curr
->sched_class
->yield_to_task(rq
, p
, preempt
);
5701 schedstat_inc(rq
, yld_count
);
5703 * Make p's CPU reschedule; pick_next_entity takes care of
5706 if (preempt
&& rq
!= p_rq
)
5707 resched_task(p_rq
->curr
);
5711 double_rq_unlock(rq
, p_rq
);
5712 local_irq_restore(flags
);
5719 EXPORT_SYMBOL_GPL(yield_to
);
5722 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
5723 * that process accounting knows that this is a task in IO wait state.
5725 void __sched
io_schedule(void)
5727 struct rq
*rq
= raw_rq();
5729 delayacct_blkio_start();
5730 atomic_inc(&rq
->nr_iowait
);
5731 blk_flush_plug(current
);
5732 current
->in_iowait
= 1;
5734 current
->in_iowait
= 0;
5735 atomic_dec(&rq
->nr_iowait
);
5736 delayacct_blkio_end();
5738 EXPORT_SYMBOL(io_schedule
);
5740 long __sched
io_schedule_timeout(long timeout
)
5742 struct rq
*rq
= raw_rq();
5745 delayacct_blkio_start();
5746 atomic_inc(&rq
->nr_iowait
);
5747 blk_flush_plug(current
);
5748 current
->in_iowait
= 1;
5749 ret
= schedule_timeout(timeout
);
5750 current
->in_iowait
= 0;
5751 atomic_dec(&rq
->nr_iowait
);
5752 delayacct_blkio_end();
5757 * sys_sched_get_priority_max - return maximum RT priority.
5758 * @policy: scheduling class.
5760 * this syscall returns the maximum rt_priority that can be used
5761 * by a given scheduling class.
5763 SYSCALL_DEFINE1(sched_get_priority_max
, int, policy
)
5770 ret
= MAX_USER_RT_PRIO
-1;
5782 * sys_sched_get_priority_min - return minimum RT priority.
5783 * @policy: scheduling class.
5785 * this syscall returns the minimum rt_priority that can be used
5786 * by a given scheduling class.
5788 SYSCALL_DEFINE1(sched_get_priority_min
, int, policy
)
5806 * sys_sched_rr_get_interval - return the default timeslice of a process.
5807 * @pid: pid of the process.
5808 * @interval: userspace pointer to the timeslice value.
5810 * this syscall writes the default timeslice value of a given process
5811 * into the user-space timespec buffer. A value of '0' means infinity.
5813 SYSCALL_DEFINE2(sched_rr_get_interval
, pid_t
, pid
,
5814 struct timespec __user
*, interval
)
5816 struct task_struct
*p
;
5817 unsigned int time_slice
;
5818 unsigned long flags
;
5828 p
= find_process_by_pid(pid
);
5832 retval
= security_task_getscheduler(p
);
5836 rq
= task_rq_lock(p
, &flags
);
5837 time_slice
= p
->sched_class
->get_rr_interval(rq
, p
);
5838 task_rq_unlock(rq
, p
, &flags
);
5841 jiffies_to_timespec(time_slice
, &t
);
5842 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
5850 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
5852 void sched_show_task(struct task_struct
*p
)
5854 unsigned long free
= 0;
5857 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
5858 printk(KERN_INFO
"%-15.15s %c", p
->comm
,
5859 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
5860 #if BITS_PER_LONG == 32
5861 if (state
== TASK_RUNNING
)
5862 printk(KERN_CONT
" running ");
5864 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
5866 if (state
== TASK_RUNNING
)
5867 printk(KERN_CONT
" running task ");
5869 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
5871 #ifdef CONFIG_DEBUG_STACK_USAGE
5872 free
= stack_not_used(p
);
5874 printk(KERN_CONT
"%5lu %5d %6d 0x%08lx\n", free
,
5875 task_pid_nr(p
), task_pid_nr(p
->real_parent
),
5876 (unsigned long)task_thread_info(p
)->flags
);
5878 show_stack(p
, NULL
);
5881 void show_state_filter(unsigned long state_filter
)
5883 struct task_struct
*g
, *p
;
5885 #if BITS_PER_LONG == 32
5887 " task PC stack pid father\n");
5890 " task PC stack pid father\n");
5892 read_lock(&tasklist_lock
);
5893 do_each_thread(g
, p
) {
5895 * reset the NMI-timeout, listing all files on a slow
5896 * console might take a lot of time:
5898 touch_nmi_watchdog();
5899 if (!state_filter
|| (p
->state
& state_filter
))
5901 } while_each_thread(g
, p
);
5903 touch_all_softlockup_watchdogs();
5905 #ifdef CONFIG_SCHED_DEBUG
5906 sysrq_sched_debug_show();
5908 read_unlock(&tasklist_lock
);
5910 * Only show locks if all tasks are dumped:
5913 debug_show_all_locks();
5916 void __cpuinit
init_idle_bootup_task(struct task_struct
*idle
)
5918 idle
->sched_class
= &idle_sched_class
;
5922 * init_idle - set up an idle thread for a given CPU
5923 * @idle: task in question
5924 * @cpu: cpu the idle task belongs to
5926 * NOTE: this function does not set the idle thread's NEED_RESCHED
5927 * flag, to make booting more robust.
5929 void __cpuinit
init_idle(struct task_struct
*idle
, int cpu
)
5931 struct rq
*rq
= cpu_rq(cpu
);
5932 unsigned long flags
;
5934 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5937 idle
->state
= TASK_RUNNING
;
5938 idle
->se
.exec_start
= sched_clock();
5940 do_set_cpus_allowed(idle
, cpumask_of(cpu
));
5942 * We're having a chicken and egg problem, even though we are
5943 * holding rq->lock, the cpu isn't yet set to this cpu so the
5944 * lockdep check in task_group() will fail.
5946 * Similar case to sched_fork(). / Alternatively we could
5947 * use task_rq_lock() here and obtain the other rq->lock.
5952 __set_task_cpu(idle
, cpu
);
5955 rq
->curr
= rq
->idle
= idle
;
5956 #if defined(CONFIG_SMP)
5959 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5961 /* Set the preempt count _outside_ the spinlocks! */
5962 task_thread_info(idle
)->preempt_count
= 0;
5965 * The idle tasks have their own, simple scheduling class:
5967 idle
->sched_class
= &idle_sched_class
;
5968 ftrace_graph_init_idle_task(idle
, cpu
);
5972 * In a system that switches off the HZ timer nohz_cpu_mask
5973 * indicates which cpus entered this state. This is used
5974 * in the rcu update to wait only for active cpus. For system
5975 * which do not switch off the HZ timer nohz_cpu_mask should
5976 * always be CPU_BITS_NONE.
5978 cpumask_var_t nohz_cpu_mask
;
5981 * Increase the granularity value when there are more CPUs,
5982 * because with more CPUs the 'effective latency' as visible
5983 * to users decreases. But the relationship is not linear,
5984 * so pick a second-best guess by going with the log2 of the
5987 * This idea comes from the SD scheduler of Con Kolivas:
5989 static int get_update_sysctl_factor(void)
5991 unsigned int cpus
= min_t(int, num_online_cpus(), 8);
5992 unsigned int factor
;
5994 switch (sysctl_sched_tunable_scaling
) {
5995 case SCHED_TUNABLESCALING_NONE
:
5998 case SCHED_TUNABLESCALING_LINEAR
:
6001 case SCHED_TUNABLESCALING_LOG
:
6003 factor
= 1 + ilog2(cpus
);
6010 static void update_sysctl(void)
6012 unsigned int factor
= get_update_sysctl_factor();
6014 #define SET_SYSCTL(name) \
6015 (sysctl_##name = (factor) * normalized_sysctl_##name)
6016 SET_SYSCTL(sched_min_granularity
);
6017 SET_SYSCTL(sched_latency
);
6018 SET_SYSCTL(sched_wakeup_granularity
);
6022 static inline void sched_init_granularity(void)
6028 void do_set_cpus_allowed(struct task_struct
*p
, const struct cpumask
*new_mask
)
6030 if (p
->sched_class
&& p
->sched_class
->set_cpus_allowed
)
6031 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
6033 cpumask_copy(&p
->cpus_allowed
, new_mask
);
6034 p
->rt
.nr_cpus_allowed
= cpumask_weight(new_mask
);
6039 * This is how migration works:
6041 * 1) we invoke migration_cpu_stop() on the target CPU using
6043 * 2) stopper starts to run (implicitly forcing the migrated thread
6045 * 3) it checks whether the migrated task is still in the wrong runqueue.
6046 * 4) if it's in the wrong runqueue then the migration thread removes
6047 * it and puts it into the right queue.
6048 * 5) stopper completes and stop_one_cpu() returns and the migration
6053 * Change a given task's CPU affinity. Migrate the thread to a
6054 * proper CPU and schedule it away if the CPU it's executing on
6055 * is removed from the allowed bitmask.
6057 * NOTE: the caller must have a valid reference to the task, the
6058 * task must not exit() & deallocate itself prematurely. The
6059 * call is not atomic; no spinlocks may be held.
6061 int set_cpus_allowed_ptr(struct task_struct
*p
, const struct cpumask
*new_mask
)
6063 unsigned long flags
;
6065 unsigned int dest_cpu
;
6068 rq
= task_rq_lock(p
, &flags
);
6070 if (cpumask_equal(&p
->cpus_allowed
, new_mask
))
6073 if (!cpumask_intersects(new_mask
, cpu_active_mask
)) {
6078 if (unlikely((p
->flags
& PF_THREAD_BOUND
) && p
!= current
)) {
6083 do_set_cpus_allowed(p
, new_mask
);
6085 /* Can the task run on the task's current CPU? If so, we're done */
6086 if (cpumask_test_cpu(task_cpu(p
), new_mask
))
6089 dest_cpu
= cpumask_any_and(cpu_active_mask
, new_mask
);
6091 struct migration_arg arg
= { p
, dest_cpu
};
6092 /* Need help from migration thread: drop lock and wait. */
6093 task_rq_unlock(rq
, p
, &flags
);
6094 stop_one_cpu(cpu_of(rq
), migration_cpu_stop
, &arg
);
6095 tlb_migrate_finish(p
->mm
);
6099 task_rq_unlock(rq
, p
, &flags
);
6103 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
6106 * Move (not current) task off this cpu, onto dest cpu. We're doing
6107 * this because either it can't run here any more (set_cpus_allowed()
6108 * away from this CPU, or CPU going down), or because we're
6109 * attempting to rebalance this task on exec (sched_exec).
6111 * So we race with normal scheduler movements, but that's OK, as long
6112 * as the task is no longer on this CPU.
6114 * Returns non-zero if task was successfully migrated.
6116 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
6118 struct rq
*rq_dest
, *rq_src
;
6121 if (unlikely(!cpu_active(dest_cpu
)))
6124 rq_src
= cpu_rq(src_cpu
);
6125 rq_dest
= cpu_rq(dest_cpu
);
6127 raw_spin_lock(&p
->pi_lock
);
6128 double_rq_lock(rq_src
, rq_dest
);
6129 /* Already moved. */
6130 if (task_cpu(p
) != src_cpu
)
6132 /* Affinity changed (again). */
6133 if (!cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
6137 * If we're not on a rq, the next wake-up will ensure we're
6141 deactivate_task(rq_src
, p
, 0);
6142 set_task_cpu(p
, dest_cpu
);
6143 activate_task(rq_dest
, p
, 0);
6144 check_preempt_curr(rq_dest
, p
, 0);
6149 double_rq_unlock(rq_src
, rq_dest
);
6150 raw_spin_unlock(&p
->pi_lock
);
6155 * migration_cpu_stop - this will be executed by a highprio stopper thread
6156 * and performs thread migration by bumping thread off CPU then
6157 * 'pushing' onto another runqueue.
6159 static int migration_cpu_stop(void *data
)
6161 struct migration_arg
*arg
= data
;
6164 * The original target cpu might have gone down and we might
6165 * be on another cpu but it doesn't matter.
6167 local_irq_disable();
6168 __migrate_task(arg
->task
, raw_smp_processor_id(), arg
->dest_cpu
);
6173 #ifdef CONFIG_HOTPLUG_CPU
6176 * Ensures that the idle task is using init_mm right before its cpu goes
6179 void idle_task_exit(void)
6181 struct mm_struct
*mm
= current
->active_mm
;
6183 BUG_ON(cpu_online(smp_processor_id()));
6186 switch_mm(mm
, &init_mm
, current
);
6191 * While a dead CPU has no uninterruptible tasks queued at this point,
6192 * it might still have a nonzero ->nr_uninterruptible counter, because
6193 * for performance reasons the counter is not stricly tracking tasks to
6194 * their home CPUs. So we just add the counter to another CPU's counter,
6195 * to keep the global sum constant after CPU-down:
6197 static void migrate_nr_uninterruptible(struct rq
*rq_src
)
6199 struct rq
*rq_dest
= cpu_rq(cpumask_any(cpu_active_mask
));
6201 rq_dest
->nr_uninterruptible
+= rq_src
->nr_uninterruptible
;
6202 rq_src
->nr_uninterruptible
= 0;
6206 * remove the tasks which were accounted by rq from calc_load_tasks.
6208 static void calc_global_load_remove(struct rq
*rq
)
6210 atomic_long_sub(rq
->calc_load_active
, &calc_load_tasks
);
6211 rq
->calc_load_active
= 0;
6215 * Migrate all tasks from the rq, sleeping tasks will be migrated by
6216 * try_to_wake_up()->select_task_rq().
6218 * Called with rq->lock held even though we'er in stop_machine() and
6219 * there's no concurrency possible, we hold the required locks anyway
6220 * because of lock validation efforts.
6222 static void migrate_tasks(unsigned int dead_cpu
)
6224 struct rq
*rq
= cpu_rq(dead_cpu
);
6225 struct task_struct
*next
, *stop
= rq
->stop
;
6229 * Fudge the rq selection such that the below task selection loop
6230 * doesn't get stuck on the currently eligible stop task.
6232 * We're currently inside stop_machine() and the rq is either stuck
6233 * in the stop_machine_cpu_stop() loop, or we're executing this code,
6234 * either way we should never end up calling schedule() until we're
6241 * There's this thread running, bail when that's the only
6244 if (rq
->nr_running
== 1)
6247 next
= pick_next_task(rq
);
6249 next
->sched_class
->put_prev_task(rq
, next
);
6251 /* Find suitable destination for @next, with force if needed. */
6252 dest_cpu
= select_fallback_rq(dead_cpu
, next
);
6253 raw_spin_unlock(&rq
->lock
);
6255 __migrate_task(next
, dead_cpu
, dest_cpu
);
6257 raw_spin_lock(&rq
->lock
);
6263 #endif /* CONFIG_HOTPLUG_CPU */
6265 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
6267 static struct ctl_table sd_ctl_dir
[] = {
6269 .procname
= "sched_domain",
6275 static struct ctl_table sd_ctl_root
[] = {
6277 .procname
= "kernel",
6279 .child
= sd_ctl_dir
,
6284 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
6286 struct ctl_table
*entry
=
6287 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
6292 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
6294 struct ctl_table
*entry
;
6297 * In the intermediate directories, both the child directory and
6298 * procname are dynamically allocated and could fail but the mode
6299 * will always be set. In the lowest directory the names are
6300 * static strings and all have proc handlers.
6302 for (entry
= *tablep
; entry
->mode
; entry
++) {
6304 sd_free_ctl_entry(&entry
->child
);
6305 if (entry
->proc_handler
== NULL
)
6306 kfree(entry
->procname
);
6314 set_table_entry(struct ctl_table
*entry
,
6315 const char *procname
, void *data
, int maxlen
,
6316 mode_t mode
, proc_handler
*proc_handler
)
6318 entry
->procname
= procname
;
6320 entry
->maxlen
= maxlen
;
6322 entry
->proc_handler
= proc_handler
;
6325 static struct ctl_table
*
6326 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
6328 struct ctl_table
*table
= sd_alloc_ctl_entry(13);
6333 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
6334 sizeof(long), 0644, proc_doulongvec_minmax
);
6335 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
6336 sizeof(long), 0644, proc_doulongvec_minmax
);
6337 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
6338 sizeof(int), 0644, proc_dointvec_minmax
);
6339 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
6340 sizeof(int), 0644, proc_dointvec_minmax
);
6341 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
6342 sizeof(int), 0644, proc_dointvec_minmax
);
6343 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
6344 sizeof(int), 0644, proc_dointvec_minmax
);
6345 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
6346 sizeof(int), 0644, proc_dointvec_minmax
);
6347 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
6348 sizeof(int), 0644, proc_dointvec_minmax
);
6349 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
6350 sizeof(int), 0644, proc_dointvec_minmax
);
6351 set_table_entry(&table
[9], "cache_nice_tries",
6352 &sd
->cache_nice_tries
,
6353 sizeof(int), 0644, proc_dointvec_minmax
);
6354 set_table_entry(&table
[10], "flags", &sd
->flags
,
6355 sizeof(int), 0644, proc_dointvec_minmax
);
6356 set_table_entry(&table
[11], "name", sd
->name
,
6357 CORENAME_MAX_SIZE
, 0444, proc_dostring
);
6358 /* &table[12] is terminator */
6363 static ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
6365 struct ctl_table
*entry
, *table
;
6366 struct sched_domain
*sd
;
6367 int domain_num
= 0, i
;
6370 for_each_domain(cpu
, sd
)
6372 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
6377 for_each_domain(cpu
, sd
) {
6378 snprintf(buf
, 32, "domain%d", i
);
6379 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
6381 entry
->child
= sd_alloc_ctl_domain_table(sd
);
6388 static struct ctl_table_header
*sd_sysctl_header
;
6389 static void register_sched_domain_sysctl(void)
6391 int i
, cpu_num
= num_possible_cpus();
6392 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
6395 WARN_ON(sd_ctl_dir
[0].child
);
6396 sd_ctl_dir
[0].child
= entry
;
6401 for_each_possible_cpu(i
) {
6402 snprintf(buf
, 32, "cpu%d", i
);
6403 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
6405 entry
->child
= sd_alloc_ctl_cpu_table(i
);
6409 WARN_ON(sd_sysctl_header
);
6410 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
6413 /* may be called multiple times per register */
6414 static void unregister_sched_domain_sysctl(void)
6416 if (sd_sysctl_header
)
6417 unregister_sysctl_table(sd_sysctl_header
);
6418 sd_sysctl_header
= NULL
;
6419 if (sd_ctl_dir
[0].child
)
6420 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
6423 static void register_sched_domain_sysctl(void)
6426 static void unregister_sched_domain_sysctl(void)
6431 static void set_rq_online(struct rq
*rq
)
6434 const struct sched_class
*class;
6436 cpumask_set_cpu(rq
->cpu
, rq
->rd
->online
);
6439 for_each_class(class) {
6440 if (class->rq_online
)
6441 class->rq_online(rq
);
6446 static void set_rq_offline(struct rq
*rq
)
6449 const struct sched_class
*class;
6451 for_each_class(class) {
6452 if (class->rq_offline
)
6453 class->rq_offline(rq
);
6456 cpumask_clear_cpu(rq
->cpu
, rq
->rd
->online
);
6462 * migration_call - callback that gets triggered when a CPU is added.
6463 * Here we can start up the necessary migration thread for the new CPU.
6465 static int __cpuinit
6466 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
6468 int cpu
= (long)hcpu
;
6469 unsigned long flags
;
6470 struct rq
*rq
= cpu_rq(cpu
);
6472 switch (action
& ~CPU_TASKS_FROZEN
) {
6474 case CPU_UP_PREPARE
:
6475 rq
->calc_load_update
= calc_load_update
;
6479 /* Update our root-domain */
6480 raw_spin_lock_irqsave(&rq
->lock
, flags
);
6482 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
6486 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
6489 #ifdef CONFIG_HOTPLUG_CPU
6491 sched_ttwu_pending();
6492 /* Update our root-domain */
6493 raw_spin_lock_irqsave(&rq
->lock
, flags
);
6495 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
6499 BUG_ON(rq
->nr_running
!= 1); /* the migration thread */
6500 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
6502 migrate_nr_uninterruptible(rq
);
6503 calc_global_load_remove(rq
);
6508 update_max_interval();
6514 * Register at high priority so that task migration (migrate_all_tasks)
6515 * happens before everything else. This has to be lower priority than
6516 * the notifier in the perf_event subsystem, though.
6518 static struct notifier_block __cpuinitdata migration_notifier
= {
6519 .notifier_call
= migration_call
,
6520 .priority
= CPU_PRI_MIGRATION
,
6523 static int __cpuinit
sched_cpu_active(struct notifier_block
*nfb
,
6524 unsigned long action
, void *hcpu
)
6526 switch (action
& ~CPU_TASKS_FROZEN
) {
6528 case CPU_DOWN_FAILED
:
6529 set_cpu_active((long)hcpu
, true);
6536 static int __cpuinit
sched_cpu_inactive(struct notifier_block
*nfb
,
6537 unsigned long action
, void *hcpu
)
6539 switch (action
& ~CPU_TASKS_FROZEN
) {
6540 case CPU_DOWN_PREPARE
:
6541 set_cpu_active((long)hcpu
, false);
6548 static int __init
migration_init(void)
6550 void *cpu
= (void *)(long)smp_processor_id();
6553 /* Initialize migration for the boot CPU */
6554 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
6555 BUG_ON(err
== NOTIFY_BAD
);
6556 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
6557 register_cpu_notifier(&migration_notifier
);
6559 /* Register cpu active notifiers */
6560 cpu_notifier(sched_cpu_active
, CPU_PRI_SCHED_ACTIVE
);
6561 cpu_notifier(sched_cpu_inactive
, CPU_PRI_SCHED_INACTIVE
);
6565 early_initcall(migration_init
);
6570 static cpumask_var_t sched_domains_tmpmask
; /* sched_domains_mutex */
6572 #ifdef CONFIG_SCHED_DEBUG
6574 static __read_mostly
int sched_domain_debug_enabled
;
6576 static int __init
sched_domain_debug_setup(char *str
)
6578 sched_domain_debug_enabled
= 1;
6582 early_param("sched_debug", sched_domain_debug_setup
);
6584 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
6585 struct cpumask
*groupmask
)
6587 struct sched_group
*group
= sd
->groups
;
6590 cpulist_scnprintf(str
, sizeof(str
), sched_domain_span(sd
));
6591 cpumask_clear(groupmask
);
6593 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
6595 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
6596 printk("does not load-balance\n");
6598 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
6603 printk(KERN_CONT
"span %s level %s\n", str
, sd
->name
);
6605 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
6606 printk(KERN_ERR
"ERROR: domain->span does not contain "
6609 if (!cpumask_test_cpu(cpu
, sched_group_cpus(group
))) {
6610 printk(KERN_ERR
"ERROR: domain->groups does not contain"
6614 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
6618 printk(KERN_ERR
"ERROR: group is NULL\n");
6622 if (!group
->sgp
->power
) {
6623 printk(KERN_CONT
"\n");
6624 printk(KERN_ERR
"ERROR: domain->cpu_power not "
6629 if (!cpumask_weight(sched_group_cpus(group
))) {
6630 printk(KERN_CONT
"\n");
6631 printk(KERN_ERR
"ERROR: empty group\n");
6635 if (cpumask_intersects(groupmask
, sched_group_cpus(group
))) {
6636 printk(KERN_CONT
"\n");
6637 printk(KERN_ERR
"ERROR: repeated CPUs\n");
6641 cpumask_or(groupmask
, groupmask
, sched_group_cpus(group
));
6643 cpulist_scnprintf(str
, sizeof(str
), sched_group_cpus(group
));
6645 printk(KERN_CONT
" %s", str
);
6646 if (group
->sgp
->power
!= SCHED_POWER_SCALE
) {
6647 printk(KERN_CONT
" (cpu_power = %d)",
6651 group
= group
->next
;
6652 } while (group
!= sd
->groups
);
6653 printk(KERN_CONT
"\n");
6655 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
6656 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
6659 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
6660 printk(KERN_ERR
"ERROR: parent span is not a superset "
6661 "of domain->span\n");
6665 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
6669 if (!sched_domain_debug_enabled
)
6673 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
6677 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
6680 if (sched_domain_debug_one(sd
, cpu
, level
, sched_domains_tmpmask
))
6688 #else /* !CONFIG_SCHED_DEBUG */
6689 # define sched_domain_debug(sd, cpu) do { } while (0)
6690 #endif /* CONFIG_SCHED_DEBUG */
6692 static int sd_degenerate(struct sched_domain
*sd
)
6694 if (cpumask_weight(sched_domain_span(sd
)) == 1)
6697 /* Following flags need at least 2 groups */
6698 if (sd
->flags
& (SD_LOAD_BALANCE
|
6699 SD_BALANCE_NEWIDLE
|
6703 SD_SHARE_PKG_RESOURCES
)) {
6704 if (sd
->groups
!= sd
->groups
->next
)
6708 /* Following flags don't use groups */
6709 if (sd
->flags
& (SD_WAKE_AFFINE
))
6716 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
6718 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
6720 if (sd_degenerate(parent
))
6723 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
6726 /* Flags needing groups don't count if only 1 group in parent */
6727 if (parent
->groups
== parent
->groups
->next
) {
6728 pflags
&= ~(SD_LOAD_BALANCE
|
6729 SD_BALANCE_NEWIDLE
|
6733 SD_SHARE_PKG_RESOURCES
);
6734 if (nr_node_ids
== 1)
6735 pflags
&= ~SD_SERIALIZE
;
6737 if (~cflags
& pflags
)
6743 static void free_rootdomain(struct rcu_head
*rcu
)
6745 struct root_domain
*rd
= container_of(rcu
, struct root_domain
, rcu
);
6747 cpupri_cleanup(&rd
->cpupri
);
6748 free_cpumask_var(rd
->rto_mask
);
6749 free_cpumask_var(rd
->online
);
6750 free_cpumask_var(rd
->span
);
6754 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
6756 struct root_domain
*old_rd
= NULL
;
6757 unsigned long flags
;
6759 raw_spin_lock_irqsave(&rq
->lock
, flags
);
6764 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
6767 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
6770 * If we dont want to free the old_rt yet then
6771 * set old_rd to NULL to skip the freeing later
6774 if (!atomic_dec_and_test(&old_rd
->refcount
))
6778 atomic_inc(&rd
->refcount
);
6781 cpumask_set_cpu(rq
->cpu
, rd
->span
);
6782 if (cpumask_test_cpu(rq
->cpu
, cpu_active_mask
))
6785 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
6788 call_rcu_sched(&old_rd
->rcu
, free_rootdomain
);
6791 static int init_rootdomain(struct root_domain
*rd
)
6793 memset(rd
, 0, sizeof(*rd
));
6795 if (!alloc_cpumask_var(&rd
->span
, GFP_KERNEL
))
6797 if (!alloc_cpumask_var(&rd
->online
, GFP_KERNEL
))
6799 if (!alloc_cpumask_var(&rd
->rto_mask
, GFP_KERNEL
))
6802 if (cpupri_init(&rd
->cpupri
) != 0)
6807 free_cpumask_var(rd
->rto_mask
);
6809 free_cpumask_var(rd
->online
);
6811 free_cpumask_var(rd
->span
);
6816 static void init_defrootdomain(void)
6818 init_rootdomain(&def_root_domain
);
6820 atomic_set(&def_root_domain
.refcount
, 1);
6823 static struct root_domain
*alloc_rootdomain(void)
6825 struct root_domain
*rd
;
6827 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
6831 if (init_rootdomain(rd
) != 0) {
6839 static void free_sched_groups(struct sched_group
*sg
, int free_sgp
)
6841 struct sched_group
*tmp
, *first
;
6850 if (free_sgp
&& atomic_dec_and_test(&sg
->sgp
->ref
))
6855 } while (sg
!= first
);
6858 static void free_sched_domain(struct rcu_head
*rcu
)
6860 struct sched_domain
*sd
= container_of(rcu
, struct sched_domain
, rcu
);
6863 * If its an overlapping domain it has private groups, iterate and
6866 if (sd
->flags
& SD_OVERLAP
) {
6867 free_sched_groups(sd
->groups
, 1);
6868 } else if (atomic_dec_and_test(&sd
->groups
->ref
)) {
6869 kfree(sd
->groups
->sgp
);
6875 static void destroy_sched_domain(struct sched_domain
*sd
, int cpu
)
6877 call_rcu(&sd
->rcu
, free_sched_domain
);
6880 static void destroy_sched_domains(struct sched_domain
*sd
, int cpu
)
6882 for (; sd
; sd
= sd
->parent
)
6883 destroy_sched_domain(sd
, cpu
);
6887 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
6888 * hold the hotplug lock.
6891 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
6893 struct rq
*rq
= cpu_rq(cpu
);
6894 struct sched_domain
*tmp
;
6896 /* Remove the sched domains which do not contribute to scheduling. */
6897 for (tmp
= sd
; tmp
; ) {
6898 struct sched_domain
*parent
= tmp
->parent
;
6902 if (sd_parent_degenerate(tmp
, parent
)) {
6903 tmp
->parent
= parent
->parent
;
6905 parent
->parent
->child
= tmp
;
6906 destroy_sched_domain(parent
, cpu
);
6911 if (sd
&& sd_degenerate(sd
)) {
6914 destroy_sched_domain(tmp
, cpu
);
6919 sched_domain_debug(sd
, cpu
);
6921 rq_attach_root(rq
, rd
);
6923 rcu_assign_pointer(rq
->sd
, sd
);
6924 destroy_sched_domains(tmp
, cpu
);
6927 /* cpus with isolated domains */
6928 static cpumask_var_t cpu_isolated_map
;
6930 /* Setup the mask of cpus configured for isolated domains */
6931 static int __init
isolated_cpu_setup(char *str
)
6933 alloc_bootmem_cpumask_var(&cpu_isolated_map
);
6934 cpulist_parse(str
, cpu_isolated_map
);
6938 __setup("isolcpus=", isolated_cpu_setup
);
6940 #define SD_NODES_PER_DOMAIN 16
6945 * find_next_best_node - find the next node to include in a sched_domain
6946 * @node: node whose sched_domain we're building
6947 * @used_nodes: nodes already in the sched_domain
6949 * Find the next node to include in a given scheduling domain. Simply
6950 * finds the closest node not already in the @used_nodes map.
6952 * Should use nodemask_t.
6954 static int find_next_best_node(int node
, nodemask_t
*used_nodes
)
6956 int i
, n
, val
, min_val
, best_node
= -1;
6960 for (i
= 0; i
< nr_node_ids
; i
++) {
6961 /* Start at @node */
6962 n
= (node
+ i
) % nr_node_ids
;
6964 if (!nr_cpus_node(n
))
6967 /* Skip already used nodes */
6968 if (node_isset(n
, *used_nodes
))
6971 /* Simple min distance search */
6972 val
= node_distance(node
, n
);
6974 if (val
< min_val
) {
6980 if (best_node
!= -1)
6981 node_set(best_node
, *used_nodes
);
6986 * sched_domain_node_span - get a cpumask for a node's sched_domain
6987 * @node: node whose cpumask we're constructing
6988 * @span: resulting cpumask
6990 * Given a node, construct a good cpumask for its sched_domain to span. It
6991 * should be one that prevents unnecessary balancing, but also spreads tasks
6994 static void sched_domain_node_span(int node
, struct cpumask
*span
)
6996 nodemask_t used_nodes
;
6999 cpumask_clear(span
);
7000 nodes_clear(used_nodes
);
7002 cpumask_or(span
, span
, cpumask_of_node(node
));
7003 node_set(node
, used_nodes
);
7005 for (i
= 1; i
< SD_NODES_PER_DOMAIN
; i
++) {
7006 int next_node
= find_next_best_node(node
, &used_nodes
);
7009 cpumask_or(span
, span
, cpumask_of_node(next_node
));
7013 static const struct cpumask
*cpu_node_mask(int cpu
)
7015 lockdep_assert_held(&sched_domains_mutex
);
7017 sched_domain_node_span(cpu_to_node(cpu
), sched_domains_tmpmask
);
7019 return sched_domains_tmpmask
;
7022 static const struct cpumask
*cpu_allnodes_mask(int cpu
)
7024 return cpu_possible_mask
;
7026 #endif /* CONFIG_NUMA */
7028 static const struct cpumask
*cpu_cpu_mask(int cpu
)
7030 return cpumask_of_node(cpu_to_node(cpu
));
7033 int sched_smt_power_savings
= 0, sched_mc_power_savings
= 0;
7036 struct sched_domain
**__percpu sd
;
7037 struct sched_group
**__percpu sg
;
7038 struct sched_group_power
**__percpu sgp
;
7042 struct sched_domain
** __percpu sd
;
7043 struct root_domain
*rd
;
7053 struct sched_domain_topology_level
;
7055 typedef struct sched_domain
*(*sched_domain_init_f
)(struct sched_domain_topology_level
*tl
, int cpu
);
7056 typedef const struct cpumask
*(*sched_domain_mask_f
)(int cpu
);
7058 #define SDTL_OVERLAP 0x01
7060 struct sched_domain_topology_level
{
7061 sched_domain_init_f init
;
7062 sched_domain_mask_f mask
;
7064 struct sd_data data
;
7068 build_overlap_sched_groups(struct sched_domain
*sd
, int cpu
)
7070 struct sched_group
*first
= NULL
, *last
= NULL
, *groups
= NULL
, *sg
;
7071 const struct cpumask
*span
= sched_domain_span(sd
);
7072 struct cpumask
*covered
= sched_domains_tmpmask
;
7073 struct sd_data
*sdd
= sd
->private;
7074 struct sched_domain
*child
;
7077 cpumask_clear(covered
);
7079 for_each_cpu(i
, span
) {
7080 struct cpumask
*sg_span
;
7082 if (cpumask_test_cpu(i
, covered
))
7085 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
7086 GFP_KERNEL
, cpu_to_node(i
));
7091 sg_span
= sched_group_cpus(sg
);
7093 child
= *per_cpu_ptr(sdd
->sd
, i
);
7095 child
= child
->child
;
7096 cpumask_copy(sg_span
, sched_domain_span(child
));
7098 cpumask_set_cpu(i
, sg_span
);
7100 cpumask_or(covered
, covered
, sg_span
);
7102 sg
->sgp
= *per_cpu_ptr(sdd
->sgp
, cpumask_first(sg_span
));
7103 atomic_inc(&sg
->sgp
->ref
);
7105 if (cpumask_test_cpu(cpu
, sg_span
))
7115 sd
->groups
= groups
;
7120 free_sched_groups(first
, 0);
7125 static int get_group(int cpu
, struct sd_data
*sdd
, struct sched_group
**sg
)
7127 struct sched_domain
*sd
= *per_cpu_ptr(sdd
->sd
, cpu
);
7128 struct sched_domain
*child
= sd
->child
;
7131 cpu
= cpumask_first(sched_domain_span(child
));
7134 *sg
= *per_cpu_ptr(sdd
->sg
, cpu
);
7135 (*sg
)->sgp
= *per_cpu_ptr(sdd
->sgp
, cpu
);
7136 atomic_set(&(*sg
)->sgp
->ref
, 1); /* for claim_allocations */
7143 * build_sched_groups will build a circular linked list of the groups
7144 * covered by the given span, and will set each group's ->cpumask correctly,
7145 * and ->cpu_power to 0.
7147 * Assumes the sched_domain tree is fully constructed
7150 build_sched_groups(struct sched_domain
*sd
, int cpu
)
7152 struct sched_group
*first
= NULL
, *last
= NULL
;
7153 struct sd_data
*sdd
= sd
->private;
7154 const struct cpumask
*span
= sched_domain_span(sd
);
7155 struct cpumask
*covered
;
7158 get_group(cpu
, sdd
, &sd
->groups
);
7159 atomic_inc(&sd
->groups
->ref
);
7161 if (cpu
!= cpumask_first(sched_domain_span(sd
)))
7164 lockdep_assert_held(&sched_domains_mutex
);
7165 covered
= sched_domains_tmpmask
;
7167 cpumask_clear(covered
);
7169 for_each_cpu(i
, span
) {
7170 struct sched_group
*sg
;
7171 int group
= get_group(i
, sdd
, &sg
);
7174 if (cpumask_test_cpu(i
, covered
))
7177 cpumask_clear(sched_group_cpus(sg
));
7180 for_each_cpu(j
, span
) {
7181 if (get_group(j
, sdd
, NULL
) != group
)
7184 cpumask_set_cpu(j
, covered
);
7185 cpumask_set_cpu(j
, sched_group_cpus(sg
));
7200 * Initialize sched groups cpu_power.
7202 * cpu_power indicates the capacity of sched group, which is used while
7203 * distributing the load between different sched groups in a sched domain.
7204 * Typically cpu_power for all the groups in a sched domain will be same unless
7205 * there are asymmetries in the topology. If there are asymmetries, group
7206 * having more cpu_power will pickup more load compared to the group having
7209 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
7211 struct sched_group
*sg
= sd
->groups
;
7213 WARN_ON(!sd
|| !sg
);
7216 sg
->group_weight
= cpumask_weight(sched_group_cpus(sg
));
7218 } while (sg
!= sd
->groups
);
7220 if (cpu
!= group_first_cpu(sg
))
7223 update_group_power(sd
, cpu
);
7227 * Initializers for schedule domains
7228 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
7231 #ifdef CONFIG_SCHED_DEBUG
7232 # define SD_INIT_NAME(sd, type) sd->name = #type
7234 # define SD_INIT_NAME(sd, type) do { } while (0)
7237 #define SD_INIT_FUNC(type) \
7238 static noinline struct sched_domain * \
7239 sd_init_##type(struct sched_domain_topology_level *tl, int cpu) \
7241 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); \
7242 *sd = SD_##type##_INIT; \
7243 SD_INIT_NAME(sd, type); \
7244 sd->private = &tl->data; \
7250 SD_INIT_FUNC(ALLNODES
)
7253 #ifdef CONFIG_SCHED_SMT
7254 SD_INIT_FUNC(SIBLING
)
7256 #ifdef CONFIG_SCHED_MC
7259 #ifdef CONFIG_SCHED_BOOK
7263 static int default_relax_domain_level
= -1;
7264 int sched_domain_level_max
;
7266 static int __init
setup_relax_domain_level(char *str
)
7270 val
= simple_strtoul(str
, NULL
, 0);
7271 if (val
< sched_domain_level_max
)
7272 default_relax_domain_level
= val
;
7276 __setup("relax_domain_level=", setup_relax_domain_level
);
7278 static void set_domain_attribute(struct sched_domain
*sd
,
7279 struct sched_domain_attr
*attr
)
7283 if (!attr
|| attr
->relax_domain_level
< 0) {
7284 if (default_relax_domain_level
< 0)
7287 request
= default_relax_domain_level
;
7289 request
= attr
->relax_domain_level
;
7290 if (request
< sd
->level
) {
7291 /* turn off idle balance on this domain */
7292 sd
->flags
&= ~(SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
7294 /* turn on idle balance on this domain */
7295 sd
->flags
|= (SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
7299 static void __sdt_free(const struct cpumask
*cpu_map
);
7300 static int __sdt_alloc(const struct cpumask
*cpu_map
);
7302 static void __free_domain_allocs(struct s_data
*d
, enum s_alloc what
,
7303 const struct cpumask
*cpu_map
)
7307 if (!atomic_read(&d
->rd
->refcount
))
7308 free_rootdomain(&d
->rd
->rcu
); /* fall through */
7310 free_percpu(d
->sd
); /* fall through */
7312 __sdt_free(cpu_map
); /* fall through */
7318 static enum s_alloc
__visit_domain_allocation_hell(struct s_data
*d
,
7319 const struct cpumask
*cpu_map
)
7321 memset(d
, 0, sizeof(*d
));
7323 if (__sdt_alloc(cpu_map
))
7324 return sa_sd_storage
;
7325 d
->sd
= alloc_percpu(struct sched_domain
*);
7327 return sa_sd_storage
;
7328 d
->rd
= alloc_rootdomain();
7331 return sa_rootdomain
;
7335 * NULL the sd_data elements we've used to build the sched_domain and
7336 * sched_group structure so that the subsequent __free_domain_allocs()
7337 * will not free the data we're using.
7339 static void claim_allocations(int cpu
, struct sched_domain
*sd
)
7341 struct sd_data
*sdd
= sd
->private;
7343 WARN_ON_ONCE(*per_cpu_ptr(sdd
->sd
, cpu
) != sd
);
7344 *per_cpu_ptr(sdd
->sd
, cpu
) = NULL
;
7346 if (atomic_read(&(*per_cpu_ptr(sdd
->sg
, cpu
))->ref
))
7347 *per_cpu_ptr(sdd
->sg
, cpu
) = NULL
;
7349 if (atomic_read(&(*per_cpu_ptr(sdd
->sgp
, cpu
))->ref
))
7350 *per_cpu_ptr(sdd
->sgp
, cpu
) = NULL
;
7353 #ifdef CONFIG_SCHED_SMT
7354 static const struct cpumask
*cpu_smt_mask(int cpu
)
7356 return topology_thread_cpumask(cpu
);
7361 * Topology list, bottom-up.
7363 static struct sched_domain_topology_level default_topology
[] = {
7364 #ifdef CONFIG_SCHED_SMT
7365 { sd_init_SIBLING
, cpu_smt_mask
, },
7367 #ifdef CONFIG_SCHED_MC
7368 { sd_init_MC
, cpu_coregroup_mask
, },
7370 #ifdef CONFIG_SCHED_BOOK
7371 { sd_init_BOOK
, cpu_book_mask
, },
7373 { sd_init_CPU
, cpu_cpu_mask
, },
7375 { sd_init_NODE
, cpu_node_mask
, SDTL_OVERLAP
, },
7376 { sd_init_ALLNODES
, cpu_allnodes_mask
, },
7381 static struct sched_domain_topology_level
*sched_domain_topology
= default_topology
;
7383 static int __sdt_alloc(const struct cpumask
*cpu_map
)
7385 struct sched_domain_topology_level
*tl
;
7388 for (tl
= sched_domain_topology
; tl
->init
; tl
++) {
7389 struct sd_data
*sdd
= &tl
->data
;
7391 sdd
->sd
= alloc_percpu(struct sched_domain
*);
7395 sdd
->sg
= alloc_percpu(struct sched_group
*);
7399 sdd
->sgp
= alloc_percpu(struct sched_group_power
*);
7403 for_each_cpu(j
, cpu_map
) {
7404 struct sched_domain
*sd
;
7405 struct sched_group
*sg
;
7406 struct sched_group_power
*sgp
;
7408 sd
= kzalloc_node(sizeof(struct sched_domain
) + cpumask_size(),
7409 GFP_KERNEL
, cpu_to_node(j
));
7413 *per_cpu_ptr(sdd
->sd
, j
) = sd
;
7415 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
7416 GFP_KERNEL
, cpu_to_node(j
));
7420 *per_cpu_ptr(sdd
->sg
, j
) = sg
;
7422 sgp
= kzalloc_node(sizeof(struct sched_group_power
),
7423 GFP_KERNEL
, cpu_to_node(j
));
7427 *per_cpu_ptr(sdd
->sgp
, j
) = sgp
;
7434 static void __sdt_free(const struct cpumask
*cpu_map
)
7436 struct sched_domain_topology_level
*tl
;
7439 for (tl
= sched_domain_topology
; tl
->init
; tl
++) {
7440 struct sd_data
*sdd
= &tl
->data
;
7442 for_each_cpu(j
, cpu_map
) {
7443 struct sched_domain
*sd
= *per_cpu_ptr(sdd
->sd
, j
);
7444 if (sd
&& (sd
->flags
& SD_OVERLAP
))
7445 free_sched_groups(sd
->groups
, 0);
7446 kfree(*per_cpu_ptr(sdd
->sg
, j
));
7447 kfree(*per_cpu_ptr(sdd
->sgp
, j
));
7449 free_percpu(sdd
->sd
);
7450 free_percpu(sdd
->sg
);
7451 free_percpu(sdd
->sgp
);
7455 struct sched_domain
*build_sched_domain(struct sched_domain_topology_level
*tl
,
7456 struct s_data
*d
, const struct cpumask
*cpu_map
,
7457 struct sched_domain_attr
*attr
, struct sched_domain
*child
,
7460 struct sched_domain
*sd
= tl
->init(tl
, cpu
);
7464 set_domain_attribute(sd
, attr
);
7465 cpumask_and(sched_domain_span(sd
), cpu_map
, tl
->mask(cpu
));
7467 sd
->level
= child
->level
+ 1;
7468 sched_domain_level_max
= max(sched_domain_level_max
, sd
->level
);
7477 * Build sched domains for a given set of cpus and attach the sched domains
7478 * to the individual cpus
7480 static int build_sched_domains(const struct cpumask
*cpu_map
,
7481 struct sched_domain_attr
*attr
)
7483 enum s_alloc alloc_state
= sa_none
;
7484 struct sched_domain
*sd
;
7486 int i
, ret
= -ENOMEM
;
7488 alloc_state
= __visit_domain_allocation_hell(&d
, cpu_map
);
7489 if (alloc_state
!= sa_rootdomain
)
7492 /* Set up domains for cpus specified by the cpu_map. */
7493 for_each_cpu(i
, cpu_map
) {
7494 struct sched_domain_topology_level
*tl
;
7497 for (tl
= sched_domain_topology
; tl
->init
; tl
++) {
7498 sd
= build_sched_domain(tl
, &d
, cpu_map
, attr
, sd
, i
);
7499 if (tl
->flags
& SDTL_OVERLAP
|| sched_feat(FORCE_SD_OVERLAP
))
7500 sd
->flags
|= SD_OVERLAP
;
7501 if (cpumask_equal(cpu_map
, sched_domain_span(sd
)))
7508 *per_cpu_ptr(d
.sd
, i
) = sd
;
7511 /* Build the groups for the domains */
7512 for_each_cpu(i
, cpu_map
) {
7513 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
7514 sd
->span_weight
= cpumask_weight(sched_domain_span(sd
));
7515 if (sd
->flags
& SD_OVERLAP
) {
7516 if (build_overlap_sched_groups(sd
, i
))
7519 if (build_sched_groups(sd
, i
))
7525 /* Calculate CPU power for physical packages and nodes */
7526 for (i
= nr_cpumask_bits
-1; i
>= 0; i
--) {
7527 if (!cpumask_test_cpu(i
, cpu_map
))
7530 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
7531 claim_allocations(i
, sd
);
7532 init_sched_groups_power(i
, sd
);
7536 /* Attach the domains */
7538 for_each_cpu(i
, cpu_map
) {
7539 sd
= *per_cpu_ptr(d
.sd
, i
);
7540 cpu_attach_domain(sd
, d
.rd
, i
);
7546 __free_domain_allocs(&d
, alloc_state
, cpu_map
);
7550 static cpumask_var_t
*doms_cur
; /* current sched domains */
7551 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
7552 static struct sched_domain_attr
*dattr_cur
;
7553 /* attribues of custom domains in 'doms_cur' */
7556 * Special case: If a kmalloc of a doms_cur partition (array of
7557 * cpumask) fails, then fallback to a single sched domain,
7558 * as determined by the single cpumask fallback_doms.
7560 static cpumask_var_t fallback_doms
;
7563 * arch_update_cpu_topology lets virtualized architectures update the
7564 * cpu core maps. It is supposed to return 1 if the topology changed
7565 * or 0 if it stayed the same.
7567 int __attribute__((weak
)) arch_update_cpu_topology(void)
7572 cpumask_var_t
*alloc_sched_domains(unsigned int ndoms
)
7575 cpumask_var_t
*doms
;
7577 doms
= kmalloc(sizeof(*doms
) * ndoms
, GFP_KERNEL
);
7580 for (i
= 0; i
< ndoms
; i
++) {
7581 if (!alloc_cpumask_var(&doms
[i
], GFP_KERNEL
)) {
7582 free_sched_domains(doms
, i
);
7589 void free_sched_domains(cpumask_var_t doms
[], unsigned int ndoms
)
7592 for (i
= 0; i
< ndoms
; i
++)
7593 free_cpumask_var(doms
[i
]);
7598 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
7599 * For now this just excludes isolated cpus, but could be used to
7600 * exclude other special cases in the future.
7602 static int init_sched_domains(const struct cpumask
*cpu_map
)
7606 arch_update_cpu_topology();
7608 doms_cur
= alloc_sched_domains(ndoms_cur
);
7610 doms_cur
= &fallback_doms
;
7611 cpumask_andnot(doms_cur
[0], cpu_map
, cpu_isolated_map
);
7613 err
= build_sched_domains(doms_cur
[0], NULL
);
7614 register_sched_domain_sysctl();
7620 * Detach sched domains from a group of cpus specified in cpu_map
7621 * These cpus will now be attached to the NULL domain
7623 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
7628 for_each_cpu(i
, cpu_map
)
7629 cpu_attach_domain(NULL
, &def_root_domain
, i
);
7633 /* handle null as "default" */
7634 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
7635 struct sched_domain_attr
*new, int idx_new
)
7637 struct sched_domain_attr tmp
;
7644 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
7645 new ? (new + idx_new
) : &tmp
,
7646 sizeof(struct sched_domain_attr
));
7650 * Partition sched domains as specified by the 'ndoms_new'
7651 * cpumasks in the array doms_new[] of cpumasks. This compares
7652 * doms_new[] to the current sched domain partitioning, doms_cur[].
7653 * It destroys each deleted domain and builds each new domain.
7655 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
7656 * The masks don't intersect (don't overlap.) We should setup one
7657 * sched domain for each mask. CPUs not in any of the cpumasks will
7658 * not be load balanced. If the same cpumask appears both in the
7659 * current 'doms_cur' domains and in the new 'doms_new', we can leave
7662 * The passed in 'doms_new' should be allocated using
7663 * alloc_sched_domains. This routine takes ownership of it and will
7664 * free_sched_domains it when done with it. If the caller failed the
7665 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
7666 * and partition_sched_domains() will fallback to the single partition
7667 * 'fallback_doms', it also forces the domains to be rebuilt.
7669 * If doms_new == NULL it will be replaced with cpu_online_mask.
7670 * ndoms_new == 0 is a special case for destroying existing domains,
7671 * and it will not create the default domain.
7673 * Call with hotplug lock held
7675 void partition_sched_domains(int ndoms_new
, cpumask_var_t doms_new
[],
7676 struct sched_domain_attr
*dattr_new
)
7681 mutex_lock(&sched_domains_mutex
);
7683 /* always unregister in case we don't destroy any domains */
7684 unregister_sched_domain_sysctl();
7686 /* Let architecture update cpu core mappings. */
7687 new_topology
= arch_update_cpu_topology();
7689 n
= doms_new
? ndoms_new
: 0;
7691 /* Destroy deleted domains */
7692 for (i
= 0; i
< ndoms_cur
; i
++) {
7693 for (j
= 0; j
< n
&& !new_topology
; j
++) {
7694 if (cpumask_equal(doms_cur
[i
], doms_new
[j
])
7695 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
7698 /* no match - a current sched domain not in new doms_new[] */
7699 detach_destroy_domains(doms_cur
[i
]);
7704 if (doms_new
== NULL
) {
7706 doms_new
= &fallback_doms
;
7707 cpumask_andnot(doms_new
[0], cpu_active_mask
, cpu_isolated_map
);
7708 WARN_ON_ONCE(dattr_new
);
7711 /* Build new domains */
7712 for (i
= 0; i
< ndoms_new
; i
++) {
7713 for (j
= 0; j
< ndoms_cur
&& !new_topology
; j
++) {
7714 if (cpumask_equal(doms_new
[i
], doms_cur
[j
])
7715 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
7718 /* no match - add a new doms_new */
7719 build_sched_domains(doms_new
[i
], dattr_new
? dattr_new
+ i
: NULL
);
7724 /* Remember the new sched domains */
7725 if (doms_cur
!= &fallback_doms
)
7726 free_sched_domains(doms_cur
, ndoms_cur
);
7727 kfree(dattr_cur
); /* kfree(NULL) is safe */
7728 doms_cur
= doms_new
;
7729 dattr_cur
= dattr_new
;
7730 ndoms_cur
= ndoms_new
;
7732 register_sched_domain_sysctl();
7734 mutex_unlock(&sched_domains_mutex
);
7737 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
7738 static void reinit_sched_domains(void)
7742 /* Destroy domains first to force the rebuild */
7743 partition_sched_domains(0, NULL
, NULL
);
7745 rebuild_sched_domains();
7749 static ssize_t
sched_power_savings_store(const char *buf
, size_t count
, int smt
)
7751 unsigned int level
= 0;
7753 if (sscanf(buf
, "%u", &level
) != 1)
7757 * level is always be positive so don't check for
7758 * level < POWERSAVINGS_BALANCE_NONE which is 0
7759 * What happens on 0 or 1 byte write,
7760 * need to check for count as well?
7763 if (level
>= MAX_POWERSAVINGS_BALANCE_LEVELS
)
7767 sched_smt_power_savings
= level
;
7769 sched_mc_power_savings
= level
;
7771 reinit_sched_domains();
7776 #ifdef CONFIG_SCHED_MC
7777 static ssize_t
sched_mc_power_savings_show(struct sysdev_class
*class,
7778 struct sysdev_class_attribute
*attr
,
7781 return sprintf(page
, "%u\n", sched_mc_power_savings
);
7783 static ssize_t
sched_mc_power_savings_store(struct sysdev_class
*class,
7784 struct sysdev_class_attribute
*attr
,
7785 const char *buf
, size_t count
)
7787 return sched_power_savings_store(buf
, count
, 0);
7789 static SYSDEV_CLASS_ATTR(sched_mc_power_savings
, 0644,
7790 sched_mc_power_savings_show
,
7791 sched_mc_power_savings_store
);
7794 #ifdef CONFIG_SCHED_SMT
7795 static ssize_t
sched_smt_power_savings_show(struct sysdev_class
*dev
,
7796 struct sysdev_class_attribute
*attr
,
7799 return sprintf(page
, "%u\n", sched_smt_power_savings
);
7801 static ssize_t
sched_smt_power_savings_store(struct sysdev_class
*dev
,
7802 struct sysdev_class_attribute
*attr
,
7803 const char *buf
, size_t count
)
7805 return sched_power_savings_store(buf
, count
, 1);
7807 static SYSDEV_CLASS_ATTR(sched_smt_power_savings
, 0644,
7808 sched_smt_power_savings_show
,
7809 sched_smt_power_savings_store
);
7812 int __init
sched_create_sysfs_power_savings_entries(struct sysdev_class
*cls
)
7816 #ifdef CONFIG_SCHED_SMT
7818 err
= sysfs_create_file(&cls
->kset
.kobj
,
7819 &attr_sched_smt_power_savings
.attr
);
7821 #ifdef CONFIG_SCHED_MC
7822 if (!err
&& mc_capable())
7823 err
= sysfs_create_file(&cls
->kset
.kobj
,
7824 &attr_sched_mc_power_savings
.attr
);
7828 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
7831 * Update cpusets according to cpu_active mask. If cpusets are
7832 * disabled, cpuset_update_active_cpus() becomes a simple wrapper
7833 * around partition_sched_domains().
7835 static int cpuset_cpu_active(struct notifier_block
*nfb
, unsigned long action
,
7838 switch (action
& ~CPU_TASKS_FROZEN
) {
7840 case CPU_DOWN_FAILED
:
7841 cpuset_update_active_cpus();
7848 static int cpuset_cpu_inactive(struct notifier_block
*nfb
, unsigned long action
,
7851 switch (action
& ~CPU_TASKS_FROZEN
) {
7852 case CPU_DOWN_PREPARE
:
7853 cpuset_update_active_cpus();
7860 static int update_runtime(struct notifier_block
*nfb
,
7861 unsigned long action
, void *hcpu
)
7863 int cpu
= (int)(long)hcpu
;
7866 case CPU_DOWN_PREPARE
:
7867 case CPU_DOWN_PREPARE_FROZEN
:
7868 disable_runtime(cpu_rq(cpu
));
7871 case CPU_DOWN_FAILED
:
7872 case CPU_DOWN_FAILED_FROZEN
:
7874 case CPU_ONLINE_FROZEN
:
7875 enable_runtime(cpu_rq(cpu
));
7883 void __init
sched_init_smp(void)
7885 cpumask_var_t non_isolated_cpus
;
7887 alloc_cpumask_var(&non_isolated_cpus
, GFP_KERNEL
);
7888 alloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
7891 mutex_lock(&sched_domains_mutex
);
7892 init_sched_domains(cpu_active_mask
);
7893 cpumask_andnot(non_isolated_cpus
, cpu_possible_mask
, cpu_isolated_map
);
7894 if (cpumask_empty(non_isolated_cpus
))
7895 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus
);
7896 mutex_unlock(&sched_domains_mutex
);
7899 hotcpu_notifier(cpuset_cpu_active
, CPU_PRI_CPUSET_ACTIVE
);
7900 hotcpu_notifier(cpuset_cpu_inactive
, CPU_PRI_CPUSET_INACTIVE
);
7902 /* RT runtime code needs to handle some hotplug events */
7903 hotcpu_notifier(update_runtime
, 0);
7907 /* Move init over to a non-isolated CPU */
7908 if (set_cpus_allowed_ptr(current
, non_isolated_cpus
) < 0)
7910 sched_init_granularity();
7911 free_cpumask_var(non_isolated_cpus
);
7913 init_sched_rt_class();
7916 void __init
sched_init_smp(void)
7918 sched_init_granularity();
7920 #endif /* CONFIG_SMP */
7922 const_debug
unsigned int sysctl_timer_migration
= 1;
7924 int in_sched_functions(unsigned long addr
)
7926 return in_lock_functions(addr
) ||
7927 (addr
>= (unsigned long)__sched_text_start
7928 && addr
< (unsigned long)__sched_text_end
);
7931 static void init_cfs_rq(struct cfs_rq
*cfs_rq
)
7933 cfs_rq
->tasks_timeline
= RB_ROOT
;
7934 INIT_LIST_HEAD(&cfs_rq
->tasks
);
7935 cfs_rq
->min_vruntime
= (u64
)(-(1LL << 20));
7936 #ifndef CONFIG_64BIT
7937 cfs_rq
->min_vruntime_copy
= cfs_rq
->min_vruntime
;
7941 static void init_rt_rq(struct rt_rq
*rt_rq
, struct rq
*rq
)
7943 struct rt_prio_array
*array
;
7946 array
= &rt_rq
->active
;
7947 for (i
= 0; i
< MAX_RT_PRIO
; i
++) {
7948 INIT_LIST_HEAD(array
->queue
+ i
);
7949 __clear_bit(i
, array
->bitmap
);
7951 /* delimiter for bitsearch: */
7952 __set_bit(MAX_RT_PRIO
, array
->bitmap
);
7954 #if defined CONFIG_SMP
7955 rt_rq
->highest_prio
.curr
= MAX_RT_PRIO
;
7956 rt_rq
->highest_prio
.next
= MAX_RT_PRIO
;
7957 rt_rq
->rt_nr_migratory
= 0;
7958 rt_rq
->overloaded
= 0;
7959 plist_head_init(&rt_rq
->pushable_tasks
);
7963 rt_rq
->rt_throttled
= 0;
7964 rt_rq
->rt_runtime
= 0;
7965 raw_spin_lock_init(&rt_rq
->rt_runtime_lock
);
7968 #ifdef CONFIG_FAIR_GROUP_SCHED
7969 static void init_tg_cfs_entry(struct task_group
*tg
, struct cfs_rq
*cfs_rq
,
7970 struct sched_entity
*se
, int cpu
,
7971 struct sched_entity
*parent
)
7973 struct rq
*rq
= cpu_rq(cpu
);
7978 /* allow initial update_cfs_load() to truncate */
7979 cfs_rq
->load_stamp
= 1;
7982 tg
->cfs_rq
[cpu
] = cfs_rq
;
7985 /* se could be NULL for root_task_group */
7990 se
->cfs_rq
= &rq
->cfs
;
7992 se
->cfs_rq
= parent
->my_q
;
7995 update_load_set(&se
->load
, 0);
7996 se
->parent
= parent
;
8000 #ifdef CONFIG_RT_GROUP_SCHED
8001 static void init_tg_rt_entry(struct task_group
*tg
, struct rt_rq
*rt_rq
,
8002 struct sched_rt_entity
*rt_se
, int cpu
,
8003 struct sched_rt_entity
*parent
)
8005 struct rq
*rq
= cpu_rq(cpu
);
8007 rt_rq
->highest_prio
.curr
= MAX_RT_PRIO
;
8008 rt_rq
->rt_nr_boosted
= 0;
8012 tg
->rt_rq
[cpu
] = rt_rq
;
8013 tg
->rt_se
[cpu
] = rt_se
;
8019 rt_se
->rt_rq
= &rq
->rt
;
8021 rt_se
->rt_rq
= parent
->my_q
;
8023 rt_se
->my_q
= rt_rq
;
8024 rt_se
->parent
= parent
;
8025 INIT_LIST_HEAD(&rt_se
->run_list
);
8029 void __init
sched_init(void)
8032 unsigned long alloc_size
= 0, ptr
;
8034 #ifdef CONFIG_FAIR_GROUP_SCHED
8035 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
8037 #ifdef CONFIG_RT_GROUP_SCHED
8038 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
8040 #ifdef CONFIG_CPUMASK_OFFSTACK
8041 alloc_size
+= num_possible_cpus() * cpumask_size();
8044 ptr
= (unsigned long)kzalloc(alloc_size
, GFP_NOWAIT
);
8046 #ifdef CONFIG_FAIR_GROUP_SCHED
8047 root_task_group
.se
= (struct sched_entity
**)ptr
;
8048 ptr
+= nr_cpu_ids
* sizeof(void **);
8050 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
8051 ptr
+= nr_cpu_ids
* sizeof(void **);
8053 #endif /* CONFIG_FAIR_GROUP_SCHED */
8054 #ifdef CONFIG_RT_GROUP_SCHED
8055 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
8056 ptr
+= nr_cpu_ids
* sizeof(void **);
8058 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
8059 ptr
+= nr_cpu_ids
* sizeof(void **);
8061 #endif /* CONFIG_RT_GROUP_SCHED */
8062 #ifdef CONFIG_CPUMASK_OFFSTACK
8063 for_each_possible_cpu(i
) {
8064 per_cpu(load_balance_tmpmask
, i
) = (void *)ptr
;
8065 ptr
+= cpumask_size();
8067 #endif /* CONFIG_CPUMASK_OFFSTACK */
8071 init_defrootdomain();
8074 init_rt_bandwidth(&def_rt_bandwidth
,
8075 global_rt_period(), global_rt_runtime());
8077 #ifdef CONFIG_RT_GROUP_SCHED
8078 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
8079 global_rt_period(), global_rt_runtime());
8080 #endif /* CONFIG_RT_GROUP_SCHED */
8082 #ifdef CONFIG_CGROUP_SCHED
8083 list_add(&root_task_group
.list
, &task_groups
);
8084 INIT_LIST_HEAD(&root_task_group
.children
);
8085 autogroup_init(&init_task
);
8086 #endif /* CONFIG_CGROUP_SCHED */
8088 for_each_possible_cpu(i
) {
8092 raw_spin_lock_init(&rq
->lock
);
8094 rq
->calc_load_active
= 0;
8095 rq
->calc_load_update
= jiffies
+ LOAD_FREQ
;
8096 init_cfs_rq(&rq
->cfs
);
8097 init_rt_rq(&rq
->rt
, rq
);
8098 #ifdef CONFIG_FAIR_GROUP_SCHED
8099 root_task_group
.shares
= root_task_group_load
;
8100 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
8102 * How much cpu bandwidth does root_task_group get?
8104 * In case of task-groups formed thr' the cgroup filesystem, it
8105 * gets 100% of the cpu resources in the system. This overall
8106 * system cpu resource is divided among the tasks of
8107 * root_task_group and its child task-groups in a fair manner,
8108 * based on each entity's (task or task-group's) weight
8109 * (se->load.weight).
8111 * In other words, if root_task_group has 10 tasks of weight
8112 * 1024) and two child groups A0 and A1 (of weight 1024 each),
8113 * then A0's share of the cpu resource is:
8115 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
8117 * We achieve this by letting root_task_group's tasks sit
8118 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
8120 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, NULL
);
8121 #endif /* CONFIG_FAIR_GROUP_SCHED */
8123 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
8124 #ifdef CONFIG_RT_GROUP_SCHED
8125 INIT_LIST_HEAD(&rq
->leaf_rt_rq_list
);
8126 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, NULL
);
8129 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
8130 rq
->cpu_load
[j
] = 0;
8132 rq
->last_load_update_tick
= jiffies
;
8137 rq
->cpu_power
= SCHED_POWER_SCALE
;
8138 rq
->post_schedule
= 0;
8139 rq
->active_balance
= 0;
8140 rq
->next_balance
= jiffies
;
8145 rq
->avg_idle
= 2*sysctl_sched_migration_cost
;
8146 rq_attach_root(rq
, &def_root_domain
);
8148 rq
->nohz_balance_kick
= 0;
8149 init_sched_softirq_csd(&per_cpu(remote_sched_softirq_cb
, i
));
8153 atomic_set(&rq
->nr_iowait
, 0);
8156 set_load_weight(&init_task
);
8158 #ifdef CONFIG_PREEMPT_NOTIFIERS
8159 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
8163 open_softirq(SCHED_SOFTIRQ
, run_rebalance_domains
);
8166 #ifdef CONFIG_RT_MUTEXES
8167 plist_head_init(&init_task
.pi_waiters
);
8171 * The boot idle thread does lazy MMU switching as well:
8173 atomic_inc(&init_mm
.mm_count
);
8174 enter_lazy_tlb(&init_mm
, current
);
8177 * Make us the idle thread. Technically, schedule() should not be
8178 * called from this thread, however somewhere below it might be,
8179 * but because we are the idle thread, we just pick up running again
8180 * when this runqueue becomes "idle".
8182 init_idle(current
, smp_processor_id());
8184 calc_load_update
= jiffies
+ LOAD_FREQ
;
8187 * During early bootup we pretend to be a normal task:
8189 current
->sched_class
= &fair_sched_class
;
8191 /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */
8192 zalloc_cpumask_var(&nohz_cpu_mask
, GFP_NOWAIT
);
8194 zalloc_cpumask_var(&sched_domains_tmpmask
, GFP_NOWAIT
);
8196 zalloc_cpumask_var(&nohz
.idle_cpus_mask
, GFP_NOWAIT
);
8197 alloc_cpumask_var(&nohz
.grp_idle_mask
, GFP_NOWAIT
);
8198 atomic_set(&nohz
.load_balancer
, nr_cpu_ids
);
8199 atomic_set(&nohz
.first_pick_cpu
, nr_cpu_ids
);
8200 atomic_set(&nohz
.second_pick_cpu
, nr_cpu_ids
);
8202 /* May be allocated at isolcpus cmdline parse time */
8203 if (cpu_isolated_map
== NULL
)
8204 zalloc_cpumask_var(&cpu_isolated_map
, GFP_NOWAIT
);
8207 scheduler_running
= 1;
8210 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
8211 static inline int preempt_count_equals(int preempt_offset
)
8213 int nested
= (preempt_count() & ~PREEMPT_ACTIVE
) + rcu_preempt_depth();
8215 return (nested
== preempt_offset
);
8218 void __might_sleep(const char *file
, int line
, int preempt_offset
)
8220 static unsigned long prev_jiffy
; /* ratelimiting */
8222 if ((preempt_count_equals(preempt_offset
) && !irqs_disabled()) ||
8223 system_state
!= SYSTEM_RUNNING
|| oops_in_progress
)
8225 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
8227 prev_jiffy
= jiffies
;
8230 "BUG: sleeping function called from invalid context at %s:%d\n",
8233 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
8234 in_atomic(), irqs_disabled(),
8235 current
->pid
, current
->comm
);
8237 debug_show_held_locks(current
);
8238 if (irqs_disabled())
8239 print_irqtrace_events(current
);
8242 EXPORT_SYMBOL(__might_sleep
);
8245 #ifdef CONFIG_MAGIC_SYSRQ
8246 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
8248 const struct sched_class
*prev_class
= p
->sched_class
;
8249 int old_prio
= p
->prio
;
8254 deactivate_task(rq
, p
, 0);
8255 __setscheduler(rq
, p
, SCHED_NORMAL
, 0);
8257 activate_task(rq
, p
, 0);
8258 resched_task(rq
->curr
);
8261 check_class_changed(rq
, p
, prev_class
, old_prio
);
8264 void normalize_rt_tasks(void)
8266 struct task_struct
*g
, *p
;
8267 unsigned long flags
;
8270 read_lock_irqsave(&tasklist_lock
, flags
);
8271 do_each_thread(g
, p
) {
8273 * Only normalize user tasks:
8278 p
->se
.exec_start
= 0;
8279 #ifdef CONFIG_SCHEDSTATS
8280 p
->se
.statistics
.wait_start
= 0;
8281 p
->se
.statistics
.sleep_start
= 0;
8282 p
->se
.statistics
.block_start
= 0;
8287 * Renice negative nice level userspace
8290 if (TASK_NICE(p
) < 0 && p
->mm
)
8291 set_user_nice(p
, 0);
8295 raw_spin_lock(&p
->pi_lock
);
8296 rq
= __task_rq_lock(p
);
8298 normalize_task(rq
, p
);
8300 __task_rq_unlock(rq
);
8301 raw_spin_unlock(&p
->pi_lock
);
8302 } while_each_thread(g
, p
);
8304 read_unlock_irqrestore(&tasklist_lock
, flags
);
8307 #endif /* CONFIG_MAGIC_SYSRQ */
8309 #if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
8311 * These functions are only useful for the IA64 MCA handling, or kdb.
8313 * They can only be called when the whole system has been
8314 * stopped - every CPU needs to be quiescent, and no scheduling
8315 * activity can take place. Using them for anything else would
8316 * be a serious bug, and as a result, they aren't even visible
8317 * under any other configuration.
8321 * curr_task - return the current task for a given cpu.
8322 * @cpu: the processor in question.
8324 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
8326 struct task_struct
*curr_task(int cpu
)
8328 return cpu_curr(cpu
);
8331 #endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
8335 * set_curr_task - set the current task for a given cpu.
8336 * @cpu: the processor in question.
8337 * @p: the task pointer to set.
8339 * Description: This function must only be used when non-maskable interrupts
8340 * are serviced on a separate stack. It allows the architecture to switch the
8341 * notion of the current task on a cpu in a non-blocking manner. This function
8342 * must be called with all CPU's synchronized, and interrupts disabled, the
8343 * and caller must save the original value of the current task (see
8344 * curr_task() above) and restore that value before reenabling interrupts and
8345 * re-starting the system.
8347 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
8349 void set_curr_task(int cpu
, struct task_struct
*p
)
8356 #ifdef CONFIG_FAIR_GROUP_SCHED
8357 static void free_fair_sched_group(struct task_group
*tg
)
8361 for_each_possible_cpu(i
) {
8363 kfree(tg
->cfs_rq
[i
]);
8373 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8375 struct cfs_rq
*cfs_rq
;
8376 struct sched_entity
*se
;
8379 tg
->cfs_rq
= kzalloc(sizeof(cfs_rq
) * nr_cpu_ids
, GFP_KERNEL
);
8382 tg
->se
= kzalloc(sizeof(se
) * nr_cpu_ids
, GFP_KERNEL
);
8386 tg
->shares
= NICE_0_LOAD
;
8388 for_each_possible_cpu(i
) {
8389 cfs_rq
= kzalloc_node(sizeof(struct cfs_rq
),
8390 GFP_KERNEL
, cpu_to_node(i
));
8394 se
= kzalloc_node(sizeof(struct sched_entity
),
8395 GFP_KERNEL
, cpu_to_node(i
));
8399 init_cfs_rq(cfs_rq
);
8400 init_tg_cfs_entry(tg
, cfs_rq
, se
, i
, parent
->se
[i
]);
8411 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
8413 struct rq
*rq
= cpu_rq(cpu
);
8414 unsigned long flags
;
8417 * Only empty task groups can be destroyed; so we can speculatively
8418 * check on_list without danger of it being re-added.
8420 if (!tg
->cfs_rq
[cpu
]->on_list
)
8423 raw_spin_lock_irqsave(&rq
->lock
, flags
);
8424 list_del_leaf_cfs_rq(tg
->cfs_rq
[cpu
]);
8425 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
8427 #else /* !CONFIG_FAIR_GROUP_SCHED */
8428 static inline void free_fair_sched_group(struct task_group
*tg
)
8433 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8438 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
8441 #endif /* CONFIG_FAIR_GROUP_SCHED */
8443 #ifdef CONFIG_RT_GROUP_SCHED
8444 static void free_rt_sched_group(struct task_group
*tg
)
8449 destroy_rt_bandwidth(&tg
->rt_bandwidth
);
8451 for_each_possible_cpu(i
) {
8453 kfree(tg
->rt_rq
[i
]);
8455 kfree(tg
->rt_se
[i
]);
8463 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8465 struct rt_rq
*rt_rq
;
8466 struct sched_rt_entity
*rt_se
;
8469 tg
->rt_rq
= kzalloc(sizeof(rt_rq
) * nr_cpu_ids
, GFP_KERNEL
);
8472 tg
->rt_se
= kzalloc(sizeof(rt_se
) * nr_cpu_ids
, GFP_KERNEL
);
8476 init_rt_bandwidth(&tg
->rt_bandwidth
,
8477 ktime_to_ns(def_rt_bandwidth
.rt_period
), 0);
8479 for_each_possible_cpu(i
) {
8480 rt_rq
= kzalloc_node(sizeof(struct rt_rq
),
8481 GFP_KERNEL
, cpu_to_node(i
));
8485 rt_se
= kzalloc_node(sizeof(struct sched_rt_entity
),
8486 GFP_KERNEL
, cpu_to_node(i
));
8490 init_rt_rq(rt_rq
, cpu_rq(i
));
8491 rt_rq
->rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
8492 init_tg_rt_entry(tg
, rt_rq
, rt_se
, i
, parent
->rt_se
[i
]);
8502 #else /* !CONFIG_RT_GROUP_SCHED */
8503 static inline void free_rt_sched_group(struct task_group
*tg
)
8508 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8512 #endif /* CONFIG_RT_GROUP_SCHED */
8514 #ifdef CONFIG_CGROUP_SCHED
8515 static void free_sched_group(struct task_group
*tg
)
8517 free_fair_sched_group(tg
);
8518 free_rt_sched_group(tg
);
8523 /* allocate runqueue etc for a new task group */
8524 struct task_group
*sched_create_group(struct task_group
*parent
)
8526 struct task_group
*tg
;
8527 unsigned long flags
;
8529 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
8531 return ERR_PTR(-ENOMEM
);
8533 if (!alloc_fair_sched_group(tg
, parent
))
8536 if (!alloc_rt_sched_group(tg
, parent
))
8539 spin_lock_irqsave(&task_group_lock
, flags
);
8540 list_add_rcu(&tg
->list
, &task_groups
);
8542 WARN_ON(!parent
); /* root should already exist */
8544 tg
->parent
= parent
;
8545 INIT_LIST_HEAD(&tg
->children
);
8546 list_add_rcu(&tg
->siblings
, &parent
->children
);
8547 spin_unlock_irqrestore(&task_group_lock
, flags
);
8552 free_sched_group(tg
);
8553 return ERR_PTR(-ENOMEM
);
8556 /* rcu callback to free various structures associated with a task group */
8557 static void free_sched_group_rcu(struct rcu_head
*rhp
)
8559 /* now it should be safe to free those cfs_rqs */
8560 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
8563 /* Destroy runqueue etc associated with a task group */
8564 void sched_destroy_group(struct task_group
*tg
)
8566 unsigned long flags
;
8569 /* end participation in shares distribution */
8570 for_each_possible_cpu(i
)
8571 unregister_fair_sched_group(tg
, i
);
8573 spin_lock_irqsave(&task_group_lock
, flags
);
8574 list_del_rcu(&tg
->list
);
8575 list_del_rcu(&tg
->siblings
);
8576 spin_unlock_irqrestore(&task_group_lock
, flags
);
8578 /* wait for possible concurrent references to cfs_rqs complete */
8579 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
8582 /* change task's runqueue when it moves between groups.
8583 * The caller of this function should have put the task in its new group
8584 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
8585 * reflect its new group.
8587 void sched_move_task(struct task_struct
*tsk
)
8590 unsigned long flags
;
8593 rq
= task_rq_lock(tsk
, &flags
);
8595 running
= task_current(rq
, tsk
);
8599 dequeue_task(rq
, tsk
, 0);
8600 if (unlikely(running
))
8601 tsk
->sched_class
->put_prev_task(rq
, tsk
);
8603 #ifdef CONFIG_FAIR_GROUP_SCHED
8604 if (tsk
->sched_class
->task_move_group
)
8605 tsk
->sched_class
->task_move_group(tsk
, on_rq
);
8608 set_task_rq(tsk
, task_cpu(tsk
));
8610 if (unlikely(running
))
8611 tsk
->sched_class
->set_curr_task(rq
);
8613 enqueue_task(rq
, tsk
, 0);
8615 task_rq_unlock(rq
, tsk
, &flags
);
8617 #endif /* CONFIG_CGROUP_SCHED */
8619 #ifdef CONFIG_FAIR_GROUP_SCHED
8620 static DEFINE_MUTEX(shares_mutex
);
8622 int sched_group_set_shares(struct task_group
*tg
, unsigned long shares
)
8625 unsigned long flags
;
8628 * We can't change the weight of the root cgroup.
8633 shares
= clamp(shares
, scale_load(MIN_SHARES
), scale_load(MAX_SHARES
));
8635 mutex_lock(&shares_mutex
);
8636 if (tg
->shares
== shares
)
8639 tg
->shares
= shares
;
8640 for_each_possible_cpu(i
) {
8641 struct rq
*rq
= cpu_rq(i
);
8642 struct sched_entity
*se
;
8645 /* Propagate contribution to hierarchy */
8646 raw_spin_lock_irqsave(&rq
->lock
, flags
);
8647 for_each_sched_entity(se
)
8648 update_cfs_shares(group_cfs_rq(se
));
8649 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
8653 mutex_unlock(&shares_mutex
);
8657 unsigned long sched_group_shares(struct task_group
*tg
)
8663 #ifdef CONFIG_RT_GROUP_SCHED
8665 * Ensure that the real time constraints are schedulable.
8667 static DEFINE_MUTEX(rt_constraints_mutex
);
8669 static unsigned long to_ratio(u64 period
, u64 runtime
)
8671 if (runtime
== RUNTIME_INF
)
8674 return div64_u64(runtime
<< 20, period
);
8677 /* Must be called with tasklist_lock held */
8678 static inline int tg_has_rt_tasks(struct task_group
*tg
)
8680 struct task_struct
*g
, *p
;
8682 do_each_thread(g
, p
) {
8683 if (rt_task(p
) && rt_rq_of_se(&p
->rt
)->tg
== tg
)
8685 } while_each_thread(g
, p
);
8690 struct rt_schedulable_data
{
8691 struct task_group
*tg
;
8696 static int tg_schedulable(struct task_group
*tg
, void *data
)
8698 struct rt_schedulable_data
*d
= data
;
8699 struct task_group
*child
;
8700 unsigned long total
, sum
= 0;
8701 u64 period
, runtime
;
8703 period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8704 runtime
= tg
->rt_bandwidth
.rt_runtime
;
8707 period
= d
->rt_period
;
8708 runtime
= d
->rt_runtime
;
8712 * Cannot have more runtime than the period.
8714 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
8718 * Ensure we don't starve existing RT tasks.
8720 if (rt_bandwidth_enabled() && !runtime
&& tg_has_rt_tasks(tg
))
8723 total
= to_ratio(period
, runtime
);
8726 * Nobody can have more than the global setting allows.
8728 if (total
> to_ratio(global_rt_period(), global_rt_runtime()))
8732 * The sum of our children's runtime should not exceed our own.
8734 list_for_each_entry_rcu(child
, &tg
->children
, siblings
) {
8735 period
= ktime_to_ns(child
->rt_bandwidth
.rt_period
);
8736 runtime
= child
->rt_bandwidth
.rt_runtime
;
8738 if (child
== d
->tg
) {
8739 period
= d
->rt_period
;
8740 runtime
= d
->rt_runtime
;
8743 sum
+= to_ratio(period
, runtime
);
8752 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
8754 struct rt_schedulable_data data
= {
8756 .rt_period
= period
,
8757 .rt_runtime
= runtime
,
8760 return walk_tg_tree(tg_schedulable
, tg_nop
, &data
);
8763 static int tg_set_bandwidth(struct task_group
*tg
,
8764 u64 rt_period
, u64 rt_runtime
)
8768 mutex_lock(&rt_constraints_mutex
);
8769 read_lock(&tasklist_lock
);
8770 err
= __rt_schedulable(tg
, rt_period
, rt_runtime
);
8774 raw_spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
8775 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
8776 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
8778 for_each_possible_cpu(i
) {
8779 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
8781 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
8782 rt_rq
->rt_runtime
= rt_runtime
;
8783 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
8785 raw_spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
8787 read_unlock(&tasklist_lock
);
8788 mutex_unlock(&rt_constraints_mutex
);
8793 int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
8795 u64 rt_runtime
, rt_period
;
8797 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8798 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
8799 if (rt_runtime_us
< 0)
8800 rt_runtime
= RUNTIME_INF
;
8802 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
8805 long sched_group_rt_runtime(struct task_group
*tg
)
8809 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
8812 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
8813 do_div(rt_runtime_us
, NSEC_PER_USEC
);
8814 return rt_runtime_us
;
8817 int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
8819 u64 rt_runtime
, rt_period
;
8821 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
8822 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
8827 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
8830 long sched_group_rt_period(struct task_group
*tg
)
8834 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8835 do_div(rt_period_us
, NSEC_PER_USEC
);
8836 return rt_period_us
;
8839 static int sched_rt_global_constraints(void)
8841 u64 runtime
, period
;
8844 if (sysctl_sched_rt_period
<= 0)
8847 runtime
= global_rt_runtime();
8848 period
= global_rt_period();
8851 * Sanity check on the sysctl variables.
8853 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
8856 mutex_lock(&rt_constraints_mutex
);
8857 read_lock(&tasklist_lock
);
8858 ret
= __rt_schedulable(NULL
, 0, 0);
8859 read_unlock(&tasklist_lock
);
8860 mutex_unlock(&rt_constraints_mutex
);
8865 int sched_rt_can_attach(struct task_group
*tg
, struct task_struct
*tsk
)
8867 /* Don't accept realtime tasks when there is no way for them to run */
8868 if (rt_task(tsk
) && tg
->rt_bandwidth
.rt_runtime
== 0)
8874 #else /* !CONFIG_RT_GROUP_SCHED */
8875 static int sched_rt_global_constraints(void)
8877 unsigned long flags
;
8880 if (sysctl_sched_rt_period
<= 0)
8884 * There's always some RT tasks in the root group
8885 * -- migration, kstopmachine etc..
8887 if (sysctl_sched_rt_runtime
== 0)
8890 raw_spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
8891 for_each_possible_cpu(i
) {
8892 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
8894 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
8895 rt_rq
->rt_runtime
= global_rt_runtime();
8896 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
8898 raw_spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
8902 #endif /* CONFIG_RT_GROUP_SCHED */
8904 int sched_rt_handler(struct ctl_table
*table
, int write
,
8905 void __user
*buffer
, size_t *lenp
,
8909 int old_period
, old_runtime
;
8910 static DEFINE_MUTEX(mutex
);
8913 old_period
= sysctl_sched_rt_period
;
8914 old_runtime
= sysctl_sched_rt_runtime
;
8916 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
8918 if (!ret
&& write
) {
8919 ret
= sched_rt_global_constraints();
8921 sysctl_sched_rt_period
= old_period
;
8922 sysctl_sched_rt_runtime
= old_runtime
;
8924 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
8925 def_rt_bandwidth
.rt_period
=
8926 ns_to_ktime(global_rt_period());
8929 mutex_unlock(&mutex
);
8934 #ifdef CONFIG_CGROUP_SCHED
8936 /* return corresponding task_group object of a cgroup */
8937 static inline struct task_group
*cgroup_tg(struct cgroup
*cgrp
)
8939 return container_of(cgroup_subsys_state(cgrp
, cpu_cgroup_subsys_id
),
8940 struct task_group
, css
);
8943 static struct cgroup_subsys_state
*
8944 cpu_cgroup_create(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8946 struct task_group
*tg
, *parent
;
8948 if (!cgrp
->parent
) {
8949 /* This is early initialization for the top cgroup */
8950 return &root_task_group
.css
;
8953 parent
= cgroup_tg(cgrp
->parent
);
8954 tg
= sched_create_group(parent
);
8956 return ERR_PTR(-ENOMEM
);
8962 cpu_cgroup_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8964 struct task_group
*tg
= cgroup_tg(cgrp
);
8966 sched_destroy_group(tg
);
8970 cpu_cgroup_can_attach_task(struct cgroup
*cgrp
, struct task_struct
*tsk
)
8972 #ifdef CONFIG_RT_GROUP_SCHED
8973 if (!sched_rt_can_attach(cgroup_tg(cgrp
), tsk
))
8976 /* We don't support RT-tasks being in separate groups */
8977 if (tsk
->sched_class
!= &fair_sched_class
)
8984 cpu_cgroup_attach_task(struct cgroup
*cgrp
, struct task_struct
*tsk
)
8986 sched_move_task(tsk
);
8990 cpu_cgroup_exit(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
8991 struct cgroup
*old_cgrp
, struct task_struct
*task
)
8994 * cgroup_exit() is called in the copy_process() failure path.
8995 * Ignore this case since the task hasn't ran yet, this avoids
8996 * trying to poke a half freed task state from generic code.
8998 if (!(task
->flags
& PF_EXITING
))
9001 sched_move_task(task
);
9004 #ifdef CONFIG_FAIR_GROUP_SCHED
9005 static int cpu_shares_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
9008 return sched_group_set_shares(cgroup_tg(cgrp
), scale_load(shareval
));
9011 static u64
cpu_shares_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
9013 struct task_group
*tg
= cgroup_tg(cgrp
);
9015 return (u64
) scale_load_down(tg
->shares
);
9017 #endif /* CONFIG_FAIR_GROUP_SCHED */
9019 #ifdef CONFIG_RT_GROUP_SCHED
9020 static int cpu_rt_runtime_write(struct cgroup
*cgrp
, struct cftype
*cft
,
9023 return sched_group_set_rt_runtime(cgroup_tg(cgrp
), val
);
9026 static s64
cpu_rt_runtime_read(struct cgroup
*cgrp
, struct cftype
*cft
)
9028 return sched_group_rt_runtime(cgroup_tg(cgrp
));
9031 static int cpu_rt_period_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
9034 return sched_group_set_rt_period(cgroup_tg(cgrp
), rt_period_us
);
9037 static u64
cpu_rt_period_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
9039 return sched_group_rt_period(cgroup_tg(cgrp
));
9041 #endif /* CONFIG_RT_GROUP_SCHED */
9043 static struct cftype cpu_files
[] = {
9044 #ifdef CONFIG_FAIR_GROUP_SCHED
9047 .read_u64
= cpu_shares_read_u64
,
9048 .write_u64
= cpu_shares_write_u64
,
9051 #ifdef CONFIG_RT_GROUP_SCHED
9053 .name
= "rt_runtime_us",
9054 .read_s64
= cpu_rt_runtime_read
,
9055 .write_s64
= cpu_rt_runtime_write
,
9058 .name
= "rt_period_us",
9059 .read_u64
= cpu_rt_period_read_uint
,
9060 .write_u64
= cpu_rt_period_write_uint
,
9065 static int cpu_cgroup_populate(struct cgroup_subsys
*ss
, struct cgroup
*cont
)
9067 return cgroup_add_files(cont
, ss
, cpu_files
, ARRAY_SIZE(cpu_files
));
9070 struct cgroup_subsys cpu_cgroup_subsys
= {
9072 .create
= cpu_cgroup_create
,
9073 .destroy
= cpu_cgroup_destroy
,
9074 .can_attach_task
= cpu_cgroup_can_attach_task
,
9075 .attach_task
= cpu_cgroup_attach_task
,
9076 .exit
= cpu_cgroup_exit
,
9077 .populate
= cpu_cgroup_populate
,
9078 .subsys_id
= cpu_cgroup_subsys_id
,
9082 #endif /* CONFIG_CGROUP_SCHED */
9084 #ifdef CONFIG_CGROUP_CPUACCT
9087 * CPU accounting code for task groups.
9089 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
9090 * (balbir@in.ibm.com).
9093 /* track cpu usage of a group of tasks and its child groups */
9095 struct cgroup_subsys_state css
;
9096 /* cpuusage holds pointer to a u64-type object on every cpu */
9097 u64 __percpu
*cpuusage
;
9098 struct percpu_counter cpustat
[CPUACCT_STAT_NSTATS
];
9099 struct cpuacct
*parent
;
9102 struct cgroup_subsys cpuacct_subsys
;
9104 /* return cpu accounting group corresponding to this container */
9105 static inline struct cpuacct
*cgroup_ca(struct cgroup
*cgrp
)
9107 return container_of(cgroup_subsys_state(cgrp
, cpuacct_subsys_id
),
9108 struct cpuacct
, css
);
9111 /* return cpu accounting group to which this task belongs */
9112 static inline struct cpuacct
*task_ca(struct task_struct
*tsk
)
9114 return container_of(task_subsys_state(tsk
, cpuacct_subsys_id
),
9115 struct cpuacct
, css
);
9118 /* create a new cpu accounting group */
9119 static struct cgroup_subsys_state
*cpuacct_create(
9120 struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9122 struct cpuacct
*ca
= kzalloc(sizeof(*ca
), GFP_KERNEL
);
9128 ca
->cpuusage
= alloc_percpu(u64
);
9132 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++)
9133 if (percpu_counter_init(&ca
->cpustat
[i
], 0))
9134 goto out_free_counters
;
9137 ca
->parent
= cgroup_ca(cgrp
->parent
);
9143 percpu_counter_destroy(&ca
->cpustat
[i
]);
9144 free_percpu(ca
->cpuusage
);
9148 return ERR_PTR(-ENOMEM
);
9151 /* destroy an existing cpu accounting group */
9153 cpuacct_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9155 struct cpuacct
*ca
= cgroup_ca(cgrp
);
9158 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++)
9159 percpu_counter_destroy(&ca
->cpustat
[i
]);
9160 free_percpu(ca
->cpuusage
);
9164 static u64
cpuacct_cpuusage_read(struct cpuacct
*ca
, int cpu
)
9166 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
9169 #ifndef CONFIG_64BIT
9171 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
9173 raw_spin_lock_irq(&cpu_rq(cpu
)->lock
);
9175 raw_spin_unlock_irq(&cpu_rq(cpu
)->lock
);
9183 static void cpuacct_cpuusage_write(struct cpuacct
*ca
, int cpu
, u64 val
)
9185 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
9187 #ifndef CONFIG_64BIT
9189 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
9191 raw_spin_lock_irq(&cpu_rq(cpu
)->lock
);
9193 raw_spin_unlock_irq(&cpu_rq(cpu
)->lock
);
9199 /* return total cpu usage (in nanoseconds) of a group */
9200 static u64
cpuusage_read(struct cgroup
*cgrp
, struct cftype
*cft
)
9202 struct cpuacct
*ca
= cgroup_ca(cgrp
);
9203 u64 totalcpuusage
= 0;
9206 for_each_present_cpu(i
)
9207 totalcpuusage
+= cpuacct_cpuusage_read(ca
, i
);
9209 return totalcpuusage
;
9212 static int cpuusage_write(struct cgroup
*cgrp
, struct cftype
*cftype
,
9215 struct cpuacct
*ca
= cgroup_ca(cgrp
);
9224 for_each_present_cpu(i
)
9225 cpuacct_cpuusage_write(ca
, i
, 0);
9231 static int cpuacct_percpu_seq_read(struct cgroup
*cgroup
, struct cftype
*cft
,
9234 struct cpuacct
*ca
= cgroup_ca(cgroup
);
9238 for_each_present_cpu(i
) {
9239 percpu
= cpuacct_cpuusage_read(ca
, i
);
9240 seq_printf(m
, "%llu ", (unsigned long long) percpu
);
9242 seq_printf(m
, "\n");
9246 static const char *cpuacct_stat_desc
[] = {
9247 [CPUACCT_STAT_USER
] = "user",
9248 [CPUACCT_STAT_SYSTEM
] = "system",
9251 static int cpuacct_stats_show(struct cgroup
*cgrp
, struct cftype
*cft
,
9252 struct cgroup_map_cb
*cb
)
9254 struct cpuacct
*ca
= cgroup_ca(cgrp
);
9257 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++) {
9258 s64 val
= percpu_counter_read(&ca
->cpustat
[i
]);
9259 val
= cputime64_to_clock_t(val
);
9260 cb
->fill(cb
, cpuacct_stat_desc
[i
], val
);
9265 static struct cftype files
[] = {
9268 .read_u64
= cpuusage_read
,
9269 .write_u64
= cpuusage_write
,
9272 .name
= "usage_percpu",
9273 .read_seq_string
= cpuacct_percpu_seq_read
,
9277 .read_map
= cpuacct_stats_show
,
9281 static int cpuacct_populate(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9283 return cgroup_add_files(cgrp
, ss
, files
, ARRAY_SIZE(files
));
9287 * charge this task's execution time to its accounting group.
9289 * called with rq->lock held.
9291 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
)
9296 if (unlikely(!cpuacct_subsys
.active
))
9299 cpu
= task_cpu(tsk
);
9305 for (; ca
; ca
= ca
->parent
) {
9306 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
9307 *cpuusage
+= cputime
;
9314 * When CONFIG_VIRT_CPU_ACCOUNTING is enabled one jiffy can be very large
9315 * in cputime_t units. As a result, cpuacct_update_stats calls
9316 * percpu_counter_add with values large enough to always overflow the
9317 * per cpu batch limit causing bad SMP scalability.
9319 * To fix this we scale percpu_counter_batch by cputime_one_jiffy so we
9320 * batch the same amount of time with CONFIG_VIRT_CPU_ACCOUNTING disabled
9321 * and enabled. We cap it at INT_MAX which is the largest allowed batch value.
9324 #define CPUACCT_BATCH \
9325 min_t(long, percpu_counter_batch * cputime_one_jiffy, INT_MAX)
9327 #define CPUACCT_BATCH 0
9331 * Charge the system/user time to the task's accounting group.
9333 static void cpuacct_update_stats(struct task_struct
*tsk
,
9334 enum cpuacct_stat_index idx
, cputime_t val
)
9337 int batch
= CPUACCT_BATCH
;
9339 if (unlikely(!cpuacct_subsys
.active
))
9346 __percpu_counter_add(&ca
->cpustat
[idx
], val
, batch
);
9352 struct cgroup_subsys cpuacct_subsys
= {
9354 .create
= cpuacct_create
,
9355 .destroy
= cpuacct_destroy
,
9356 .populate
= cpuacct_populate
,
9357 .subsys_id
= cpuacct_subsys_id
,
9359 #endif /* CONFIG_CGROUP_CPUACCT */