4 * Kernel scheduler and related syscalls
6 * Copyright (C) 1991-2002 Linus Torvalds
8 * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and
9 * make semaphores SMP safe
10 * 1998-11-19 Implemented schedule_timeout() and related stuff
12 * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar:
13 * hybrid priority-list and round-robin design with
14 * an array-switch method of distributing timeslices
15 * and per-CPU runqueues. Cleanups and useful suggestions
16 * by Davide Libenzi, preemptible kernel bits by Robert Love.
17 * 2003-09-03 Interactivity tuning by Con Kolivas.
18 * 2004-04-02 Scheduler domains code by Nick Piggin
19 * 2007-04-15 Work begun on replacing all interactivity tuning with a
20 * fair scheduling design by Con Kolivas.
21 * 2007-05-05 Load balancing (smp-nice) and other improvements
23 * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith
24 * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri
25 * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins,
26 * Thomas Gleixner, Mike Kravetz
30 #include <linux/module.h>
31 #include <linux/nmi.h>
32 #include <linux/init.h>
33 #include <linux/uaccess.h>
34 #include <linux/highmem.h>
35 #include <linux/smp_lock.h>
36 #include <asm/mmu_context.h>
37 #include <linux/interrupt.h>
38 #include <linux/capability.h>
39 #include <linux/completion.h>
40 #include <linux/kernel_stat.h>
41 #include <linux/debug_locks.h>
42 #include <linux/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/kthread.h>
58 #include <linux/proc_fs.h>
59 #include <linux/seq_file.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/reciprocal_div.h>
67 #include <linux/unistd.h>
68 #include <linux/pagemap.h>
69 #include <linux/hrtimer.h>
70 #include <linux/tick.h>
71 #include <linux/bootmem.h>
72 #include <linux/debugfs.h>
73 #include <linux/ctype.h>
74 #include <linux/ftrace.h>
75 #include <trace/sched.h>
78 #include <asm/irq_regs.h>
80 #include "sched_cpupri.h"
83 * Convert user-nice values [ -20 ... 0 ... 19 ]
84 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
87 #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
88 #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
89 #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
92 * 'User priority' is the nice value converted to something we
93 * can work with better when scaling various scheduler parameters,
94 * it's a [ 0 ... 39 ] range.
96 #define USER_PRIO(p) ((p)-MAX_RT_PRIO)
97 #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
98 #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
101 * Helpers for converting nanosecond timing to jiffy resolution
103 #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
105 #define NICE_0_LOAD SCHED_LOAD_SCALE
106 #define NICE_0_SHIFT SCHED_LOAD_SHIFT
109 * These are the 'tuning knobs' of the scheduler:
111 * default timeslice is 100 msecs (used only for SCHED_RR tasks).
112 * Timeslices get refilled after they expire.
114 #define DEF_TIMESLICE (100 * HZ / 1000)
117 * single value that denotes runtime == period, ie unlimited time.
119 #define RUNTIME_INF ((u64)~0ULL)
121 DEFINE_TRACE(sched_wait_task
);
122 DEFINE_TRACE(sched_wakeup
);
123 DEFINE_TRACE(sched_wakeup_new
);
124 DEFINE_TRACE(sched_switch
);
125 DEFINE_TRACE(sched_migrate_task
);
129 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
);
132 * Divide a load by a sched group cpu_power : (load / sg->__cpu_power)
133 * Since cpu_power is a 'constant', we can use a reciprocal divide.
135 static inline u32
sg_div_cpu_power(const struct sched_group
*sg
, u32 load
)
137 return reciprocal_divide(load
, sg
->reciprocal_cpu_power
);
141 * Each time a sched group cpu_power is changed,
142 * we must compute its reciprocal value
144 static inline void sg_inc_cpu_power(struct sched_group
*sg
, u32 val
)
146 sg
->__cpu_power
+= val
;
147 sg
->reciprocal_cpu_power
= reciprocal_value(sg
->__cpu_power
);
151 static inline int rt_policy(int policy
)
153 if (unlikely(policy
== SCHED_FIFO
|| policy
== SCHED_RR
))
158 static inline int task_has_rt_policy(struct task_struct
*p
)
160 return rt_policy(p
->policy
);
164 * This is the priority-queue data structure of the RT scheduling class:
166 struct rt_prio_array
{
167 DECLARE_BITMAP(bitmap
, MAX_RT_PRIO
+1); /* include 1 bit for delimiter */
168 struct list_head queue
[MAX_RT_PRIO
];
171 struct rt_bandwidth
{
172 /* nests inside the rq lock: */
173 spinlock_t rt_runtime_lock
;
176 struct hrtimer rt_period_timer
;
179 static struct rt_bandwidth def_rt_bandwidth
;
181 static int do_sched_rt_period_timer(struct rt_bandwidth
*rt_b
, int overrun
);
183 static enum hrtimer_restart
sched_rt_period_timer(struct hrtimer
*timer
)
185 struct rt_bandwidth
*rt_b
=
186 container_of(timer
, struct rt_bandwidth
, rt_period_timer
);
192 now
= hrtimer_cb_get_time(timer
);
193 overrun
= hrtimer_forward(timer
, now
, rt_b
->rt_period
);
198 idle
= do_sched_rt_period_timer(rt_b
, overrun
);
201 return idle
? HRTIMER_NORESTART
: HRTIMER_RESTART
;
205 void init_rt_bandwidth(struct rt_bandwidth
*rt_b
, u64 period
, u64 runtime
)
207 rt_b
->rt_period
= ns_to_ktime(period
);
208 rt_b
->rt_runtime
= runtime
;
210 spin_lock_init(&rt_b
->rt_runtime_lock
);
212 hrtimer_init(&rt_b
->rt_period_timer
,
213 CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
214 rt_b
->rt_period_timer
.function
= sched_rt_period_timer
;
217 static inline int rt_bandwidth_enabled(void)
219 return sysctl_sched_rt_runtime
>= 0;
222 static void start_rt_bandwidth(struct rt_bandwidth
*rt_b
)
226 if (!rt_bandwidth_enabled() || rt_b
->rt_runtime
== RUNTIME_INF
)
229 if (hrtimer_active(&rt_b
->rt_period_timer
))
232 spin_lock(&rt_b
->rt_runtime_lock
);
237 if (hrtimer_active(&rt_b
->rt_period_timer
))
240 now
= hrtimer_cb_get_time(&rt_b
->rt_period_timer
);
241 hrtimer_forward(&rt_b
->rt_period_timer
, now
, rt_b
->rt_period
);
243 soft
= hrtimer_get_softexpires(&rt_b
->rt_period_timer
);
244 hard
= hrtimer_get_expires(&rt_b
->rt_period_timer
);
245 delta
= ktime_to_ns(ktime_sub(hard
, soft
));
246 __hrtimer_start_range_ns(&rt_b
->rt_period_timer
, soft
, delta
,
247 HRTIMER_MODE_ABS
, 0);
249 spin_unlock(&rt_b
->rt_runtime_lock
);
252 #ifdef CONFIG_RT_GROUP_SCHED
253 static void destroy_rt_bandwidth(struct rt_bandwidth
*rt_b
)
255 hrtimer_cancel(&rt_b
->rt_period_timer
);
260 * sched_domains_mutex serializes calls to arch_init_sched_domains,
261 * detach_destroy_domains and partition_sched_domains.
263 static DEFINE_MUTEX(sched_domains_mutex
);
265 #ifdef CONFIG_GROUP_SCHED
267 #include <linux/cgroup.h>
271 static LIST_HEAD(task_groups
);
273 /* task group related information */
275 #ifdef CONFIG_CGROUP_SCHED
276 struct cgroup_subsys_state css
;
279 #ifdef CONFIG_USER_SCHED
283 #ifdef CONFIG_FAIR_GROUP_SCHED
284 /* schedulable entities of this group on each cpu */
285 struct sched_entity
**se
;
286 /* runqueue "owned" by this group on each cpu */
287 struct cfs_rq
**cfs_rq
;
288 unsigned long shares
;
291 #ifdef CONFIG_RT_GROUP_SCHED
292 struct sched_rt_entity
**rt_se
;
293 struct rt_rq
**rt_rq
;
295 struct rt_bandwidth rt_bandwidth
;
299 struct list_head list
;
301 struct task_group
*parent
;
302 struct list_head siblings
;
303 struct list_head children
;
306 #ifdef CONFIG_USER_SCHED
308 /* Helper function to pass uid information to create_sched_user() */
309 void set_tg_uid(struct user_struct
*user
)
311 user
->tg
->uid
= user
->uid
;
316 * Every UID task group (including init_task_group aka UID-0) will
317 * be a child to this group.
319 struct task_group root_task_group
;
321 #ifdef CONFIG_FAIR_GROUP_SCHED
322 /* Default task group's sched entity on each cpu */
323 static DEFINE_PER_CPU(struct sched_entity
, init_sched_entity
);
324 /* Default task group's cfs_rq on each cpu */
325 static DEFINE_PER_CPU(struct cfs_rq
, init_cfs_rq
) ____cacheline_aligned_in_smp
;
326 #endif /* CONFIG_FAIR_GROUP_SCHED */
328 #ifdef CONFIG_RT_GROUP_SCHED
329 static DEFINE_PER_CPU(struct sched_rt_entity
, init_sched_rt_entity
);
330 static DEFINE_PER_CPU(struct rt_rq
, init_rt_rq
) ____cacheline_aligned_in_smp
;
331 #endif /* CONFIG_RT_GROUP_SCHED */
332 #else /* !CONFIG_USER_SCHED */
333 #define root_task_group init_task_group
334 #endif /* CONFIG_USER_SCHED */
336 /* task_group_lock serializes add/remove of task groups and also changes to
337 * a task group's cpu shares.
339 static DEFINE_SPINLOCK(task_group_lock
);
342 static int root_task_group_empty(void)
344 return list_empty(&root_task_group
.children
);
348 #ifdef CONFIG_FAIR_GROUP_SCHED
349 #ifdef CONFIG_USER_SCHED
350 # define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD)
351 #else /* !CONFIG_USER_SCHED */
352 # define INIT_TASK_GROUP_LOAD NICE_0_LOAD
353 #endif /* CONFIG_USER_SCHED */
356 * A weight of 0 or 1 can cause arithmetics problems.
357 * A weight of a cfs_rq is the sum of weights of which entities
358 * are queued on this cfs_rq, so a weight of a entity should not be
359 * too large, so as the shares value of a task group.
360 * (The default weight is 1024 - so there's no practical
361 * limitation from this.)
364 #define MAX_SHARES (1UL << 18)
366 static int init_task_group_load
= INIT_TASK_GROUP_LOAD
;
369 /* Default task group.
370 * Every task in system belong to this group at bootup.
372 struct task_group init_task_group
;
374 /* return group to which a task belongs */
375 static inline struct task_group
*task_group(struct task_struct
*p
)
377 struct task_group
*tg
;
379 #ifdef CONFIG_USER_SCHED
381 tg
= __task_cred(p
)->user
->tg
;
383 #elif defined(CONFIG_CGROUP_SCHED)
384 tg
= container_of(task_subsys_state(p
, cpu_cgroup_subsys_id
),
385 struct task_group
, css
);
387 tg
= &init_task_group
;
392 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
393 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
)
395 #ifdef CONFIG_FAIR_GROUP_SCHED
396 p
->se
.cfs_rq
= task_group(p
)->cfs_rq
[cpu
];
397 p
->se
.parent
= task_group(p
)->se
[cpu
];
400 #ifdef CONFIG_RT_GROUP_SCHED
401 p
->rt
.rt_rq
= task_group(p
)->rt_rq
[cpu
];
402 p
->rt
.parent
= task_group(p
)->rt_se
[cpu
];
409 static int root_task_group_empty(void)
415 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
) { }
416 static inline struct task_group
*task_group(struct task_struct
*p
)
421 #endif /* CONFIG_GROUP_SCHED */
423 /* CFS-related fields in a runqueue */
425 struct load_weight load
;
426 unsigned long nr_running
;
431 struct rb_root tasks_timeline
;
432 struct rb_node
*rb_leftmost
;
434 struct list_head tasks
;
435 struct list_head
*balance_iterator
;
438 * 'curr' points to currently running entity on this cfs_rq.
439 * It is set to NULL otherwise (i.e when none are currently running).
441 struct sched_entity
*curr
, *next
, *last
;
443 unsigned int nr_spread_over
;
445 #ifdef CONFIG_FAIR_GROUP_SCHED
446 struct rq
*rq
; /* cpu runqueue to which this cfs_rq is attached */
449 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
450 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
451 * (like users, containers etc.)
453 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
454 * list is used during load balance.
456 struct list_head leaf_cfs_rq_list
;
457 struct task_group
*tg
; /* group that "owns" this runqueue */
461 * the part of load.weight contributed by tasks
463 unsigned long task_weight
;
466 * h_load = weight * f(tg)
468 * Where f(tg) is the recursive weight fraction assigned to
471 unsigned long h_load
;
474 * this cpu's part of tg->shares
476 unsigned long shares
;
479 * load.weight at the time we set shares
481 unsigned long rq_weight
;
486 /* Real-Time classes' related field in a runqueue: */
488 struct rt_prio_array active
;
489 unsigned long rt_nr_running
;
490 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
492 int curr
; /* highest queued rt task prio */
494 int next
; /* next highest */
499 unsigned long rt_nr_migratory
;
501 struct plist_head pushable_tasks
;
506 /* Nests inside the rq lock: */
507 spinlock_t rt_runtime_lock
;
509 #ifdef CONFIG_RT_GROUP_SCHED
510 unsigned long rt_nr_boosted
;
513 struct list_head leaf_rt_rq_list
;
514 struct task_group
*tg
;
515 struct sched_rt_entity
*rt_se
;
522 * We add the notion of a root-domain which will be used to define per-domain
523 * variables. Each exclusive cpuset essentially defines an island domain by
524 * fully partitioning the member cpus from any other cpuset. Whenever a new
525 * exclusive cpuset is created, we also create and attach a new root-domain
532 cpumask_var_t online
;
535 * The "RT overload" flag: it gets set if a CPU has more than
536 * one runnable RT task.
538 cpumask_var_t rto_mask
;
541 struct cpupri cpupri
;
543 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
545 * Preferred wake up cpu nominated by sched_mc balance that will be
546 * used when most cpus are idle in the system indicating overall very
547 * low system utilisation. Triggered at POWERSAVINGS_BALANCE_WAKEUP(2)
549 unsigned int sched_mc_preferred_wakeup_cpu
;
554 * By default the system creates a single root-domain with all cpus as
555 * members (mimicking the global state we have today).
557 static struct root_domain def_root_domain
;
562 * This is the main, per-CPU runqueue data structure.
564 * Locking rule: those places that want to lock multiple runqueues
565 * (such as the load balancing or the thread migration code), lock
566 * acquire operations must be ordered by ascending &runqueue.
573 * nr_running and cpu_load should be in the same cacheline because
574 * remote CPUs use both these fields when doing load calculation.
576 unsigned long nr_running
;
577 #define CPU_LOAD_IDX_MAX 5
578 unsigned long cpu_load
[CPU_LOAD_IDX_MAX
];
580 unsigned long last_tick_seen
;
581 unsigned char in_nohz_recently
;
583 /* capture load from *all* tasks on this cpu: */
584 struct load_weight load
;
585 unsigned long nr_load_updates
;
591 #ifdef CONFIG_FAIR_GROUP_SCHED
592 /* list of leaf cfs_rq on this cpu: */
593 struct list_head leaf_cfs_rq_list
;
595 #ifdef CONFIG_RT_GROUP_SCHED
596 struct list_head leaf_rt_rq_list
;
600 * This is part of a global counter where only the total sum
601 * over all CPUs matters. A task can increase this counter on
602 * one CPU and if it got migrated afterwards it may decrease
603 * it on another CPU. Always updated under the runqueue lock:
605 unsigned long nr_uninterruptible
;
607 struct task_struct
*curr
, *idle
;
608 unsigned long next_balance
;
609 struct mm_struct
*prev_mm
;
616 struct root_domain
*rd
;
617 struct sched_domain
*sd
;
619 unsigned char idle_at_tick
;
620 /* For active balancing */
623 /* cpu of this runqueue: */
627 unsigned long avg_load_per_task
;
629 struct task_struct
*migration_thread
;
630 struct list_head migration_queue
;
633 #ifdef CONFIG_SCHED_HRTICK
635 int hrtick_csd_pending
;
636 struct call_single_data hrtick_csd
;
638 struct hrtimer hrtick_timer
;
641 #ifdef CONFIG_SCHEDSTATS
643 struct sched_info rq_sched_info
;
644 unsigned long long rq_cpu_time
;
645 /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
647 /* sys_sched_yield() stats */
648 unsigned int yld_count
;
650 /* schedule() stats */
651 unsigned int sched_switch
;
652 unsigned int sched_count
;
653 unsigned int sched_goidle
;
655 /* try_to_wake_up() stats */
656 unsigned int ttwu_count
;
657 unsigned int ttwu_local
;
660 unsigned int bkl_count
;
664 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
666 static inline void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int sync
)
668 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
, sync
);
671 static inline int cpu_of(struct rq
*rq
)
681 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
682 * See detach_destroy_domains: synchronize_sched for details.
684 * The domain tree of any CPU may only be accessed from within
685 * preempt-disabled sections.
687 #define for_each_domain(cpu, __sd) \
688 for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
690 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
691 #define this_rq() (&__get_cpu_var(runqueues))
692 #define task_rq(p) cpu_rq(task_cpu(p))
693 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
695 static inline void update_rq_clock(struct rq
*rq
)
697 rq
->clock
= sched_clock_cpu(cpu_of(rq
));
701 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
703 #ifdef CONFIG_SCHED_DEBUG
704 # define const_debug __read_mostly
706 # define const_debug static const
712 * Returns true if the current cpu runqueue is locked.
713 * This interface allows printk to be called with the runqueue lock
714 * held and know whether or not it is OK to wake up the klogd.
716 int runqueue_is_locked(void)
719 struct rq
*rq
= cpu_rq(cpu
);
722 ret
= spin_is_locked(&rq
->lock
);
728 * Debugging: various feature bits
731 #define SCHED_FEAT(name, enabled) \
732 __SCHED_FEAT_##name ,
735 #include "sched_features.h"
740 #define SCHED_FEAT(name, enabled) \
741 (1UL << __SCHED_FEAT_##name) * enabled |
743 const_debug
unsigned int sysctl_sched_features
=
744 #include "sched_features.h"
749 #ifdef CONFIG_SCHED_DEBUG
750 #define SCHED_FEAT(name, enabled) \
753 static __read_mostly
char *sched_feat_names
[] = {
754 #include "sched_features.h"
760 static int sched_feat_show(struct seq_file
*m
, void *v
)
764 for (i
= 0; sched_feat_names
[i
]; i
++) {
765 if (!(sysctl_sched_features
& (1UL << i
)))
767 seq_printf(m
, "%s ", sched_feat_names
[i
]);
775 sched_feat_write(struct file
*filp
, const char __user
*ubuf
,
776 size_t cnt
, loff_t
*ppos
)
786 if (copy_from_user(&buf
, ubuf
, cnt
))
791 if (strncmp(buf
, "NO_", 3) == 0) {
796 for (i
= 0; sched_feat_names
[i
]; i
++) {
797 int len
= strlen(sched_feat_names
[i
]);
799 if (strncmp(cmp
, sched_feat_names
[i
], len
) == 0) {
801 sysctl_sched_features
&= ~(1UL << i
);
803 sysctl_sched_features
|= (1UL << i
);
808 if (!sched_feat_names
[i
])
816 static int sched_feat_open(struct inode
*inode
, struct file
*filp
)
818 return single_open(filp
, sched_feat_show
, NULL
);
821 static struct file_operations sched_feat_fops
= {
822 .open
= sched_feat_open
,
823 .write
= sched_feat_write
,
826 .release
= single_release
,
829 static __init
int sched_init_debug(void)
831 debugfs_create_file("sched_features", 0644, NULL
, NULL
,
836 late_initcall(sched_init_debug
);
840 #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
843 * Number of tasks to iterate in a single balance run.
844 * Limited because this is done with IRQs disabled.
846 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
849 * ratelimit for updating the group shares.
852 unsigned int sysctl_sched_shares_ratelimit
= 250000;
855 * Inject some fuzzyness into changing the per-cpu group shares
856 * this avoids remote rq-locks at the expense of fairness.
859 unsigned int sysctl_sched_shares_thresh
= 4;
862 * period over which we measure -rt task cpu usage in us.
865 unsigned int sysctl_sched_rt_period
= 1000000;
867 static __read_mostly
int scheduler_running
;
870 * part of the period that we allow rt tasks to run in us.
873 int sysctl_sched_rt_runtime
= 950000;
875 static inline u64
global_rt_period(void)
877 return (u64
)sysctl_sched_rt_period
* NSEC_PER_USEC
;
880 static inline u64
global_rt_runtime(void)
882 if (sysctl_sched_rt_runtime
< 0)
885 return (u64
)sysctl_sched_rt_runtime
* NSEC_PER_USEC
;
888 #ifndef prepare_arch_switch
889 # define prepare_arch_switch(next) do { } while (0)
891 #ifndef finish_arch_switch
892 # define finish_arch_switch(prev) do { } while (0)
895 static inline int task_current(struct rq
*rq
, struct task_struct
*p
)
897 return rq
->curr
== p
;
900 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
901 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
903 return task_current(rq
, p
);
906 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
910 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
912 #ifdef CONFIG_DEBUG_SPINLOCK
913 /* this is a valid case when another task releases the spinlock */
914 rq
->lock
.owner
= current
;
917 * If we are tracking spinlock dependencies then we have to
918 * fix up the runqueue lock - which gets 'carried over' from
921 spin_acquire(&rq
->lock
.dep_map
, 0, 0, _THIS_IP_
);
923 spin_unlock_irq(&rq
->lock
);
926 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
927 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
932 return task_current(rq
, p
);
936 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
940 * We can optimise this out completely for !SMP, because the
941 * SMP rebalancing from interrupt is the only thing that cares
946 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
947 spin_unlock_irq(&rq
->lock
);
949 spin_unlock(&rq
->lock
);
953 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
957 * After ->oncpu is cleared, the task can be moved to a different CPU.
958 * We must ensure this doesn't happen until the switch is completely
964 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
968 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
971 * __task_rq_lock - lock the runqueue a given task resides on.
972 * Must be called interrupts disabled.
974 static inline struct rq
*__task_rq_lock(struct task_struct
*p
)
978 struct rq
*rq
= task_rq(p
);
979 spin_lock(&rq
->lock
);
980 if (likely(rq
== task_rq(p
)))
982 spin_unlock(&rq
->lock
);
987 * task_rq_lock - lock the runqueue a given task resides on and disable
988 * interrupts. Note the ordering: we can safely lookup the task_rq without
989 * explicitly disabling preemption.
991 static struct rq
*task_rq_lock(struct task_struct
*p
, unsigned long *flags
)
997 local_irq_save(*flags
);
999 spin_lock(&rq
->lock
);
1000 if (likely(rq
== task_rq(p
)))
1002 spin_unlock_irqrestore(&rq
->lock
, *flags
);
1006 void task_rq_unlock_wait(struct task_struct
*p
)
1008 struct rq
*rq
= task_rq(p
);
1010 smp_mb(); /* spin-unlock-wait is not a full memory barrier */
1011 spin_unlock_wait(&rq
->lock
);
1014 static void __task_rq_unlock(struct rq
*rq
)
1015 __releases(rq
->lock
)
1017 spin_unlock(&rq
->lock
);
1020 static inline void task_rq_unlock(struct rq
*rq
, unsigned long *flags
)
1021 __releases(rq
->lock
)
1023 spin_unlock_irqrestore(&rq
->lock
, *flags
);
1027 * this_rq_lock - lock this runqueue and disable interrupts.
1029 static struct rq
*this_rq_lock(void)
1030 __acquires(rq
->lock
)
1034 local_irq_disable();
1036 spin_lock(&rq
->lock
);
1041 #ifdef CONFIG_SCHED_HRTICK
1043 * Use HR-timers to deliver accurate preemption points.
1045 * Its all a bit involved since we cannot program an hrt while holding the
1046 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
1049 * When we get rescheduled we reprogram the hrtick_timer outside of the
1055 * - enabled by features
1056 * - hrtimer is actually high res
1058 static inline int hrtick_enabled(struct rq
*rq
)
1060 if (!sched_feat(HRTICK
))
1062 if (!cpu_active(cpu_of(rq
)))
1064 return hrtimer_is_hres_active(&rq
->hrtick_timer
);
1067 static void hrtick_clear(struct rq
*rq
)
1069 if (hrtimer_active(&rq
->hrtick_timer
))
1070 hrtimer_cancel(&rq
->hrtick_timer
);
1074 * High-resolution timer tick.
1075 * Runs from hardirq context with interrupts disabled.
1077 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
1079 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
1081 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1083 spin_lock(&rq
->lock
);
1084 update_rq_clock(rq
);
1085 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
1086 spin_unlock(&rq
->lock
);
1088 return HRTIMER_NORESTART
;
1093 * called from hardirq (IPI) context
1095 static void __hrtick_start(void *arg
)
1097 struct rq
*rq
= arg
;
1099 spin_lock(&rq
->lock
);
1100 hrtimer_restart(&rq
->hrtick_timer
);
1101 rq
->hrtick_csd_pending
= 0;
1102 spin_unlock(&rq
->lock
);
1106 * Called to set the hrtick timer state.
1108 * called with rq->lock held and irqs disabled
1110 static void hrtick_start(struct rq
*rq
, u64 delay
)
1112 struct hrtimer
*timer
= &rq
->hrtick_timer
;
1113 ktime_t time
= ktime_add_ns(timer
->base
->get_time(), delay
);
1115 hrtimer_set_expires(timer
, time
);
1117 if (rq
== this_rq()) {
1118 hrtimer_restart(timer
);
1119 } else if (!rq
->hrtick_csd_pending
) {
1120 __smp_call_function_single(cpu_of(rq
), &rq
->hrtick_csd
, 0);
1121 rq
->hrtick_csd_pending
= 1;
1126 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
1128 int cpu
= (int)(long)hcpu
;
1131 case CPU_UP_CANCELED
:
1132 case CPU_UP_CANCELED_FROZEN
:
1133 case CPU_DOWN_PREPARE
:
1134 case CPU_DOWN_PREPARE_FROZEN
:
1136 case CPU_DEAD_FROZEN
:
1137 hrtick_clear(cpu_rq(cpu
));
1144 static __init
void init_hrtick(void)
1146 hotcpu_notifier(hotplug_hrtick
, 0);
1150 * Called to set the hrtick timer state.
1152 * called with rq->lock held and irqs disabled
1154 static void hrtick_start(struct rq
*rq
, u64 delay
)
1156 __hrtimer_start_range_ns(&rq
->hrtick_timer
, ns_to_ktime(delay
), 0,
1157 HRTIMER_MODE_REL
, 0);
1160 static inline void init_hrtick(void)
1163 #endif /* CONFIG_SMP */
1165 static void init_rq_hrtick(struct rq
*rq
)
1168 rq
->hrtick_csd_pending
= 0;
1170 rq
->hrtick_csd
.flags
= 0;
1171 rq
->hrtick_csd
.func
= __hrtick_start
;
1172 rq
->hrtick_csd
.info
= rq
;
1175 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1176 rq
->hrtick_timer
.function
= hrtick
;
1178 #else /* CONFIG_SCHED_HRTICK */
1179 static inline void hrtick_clear(struct rq
*rq
)
1183 static inline void init_rq_hrtick(struct rq
*rq
)
1187 static inline void init_hrtick(void)
1190 #endif /* CONFIG_SCHED_HRTICK */
1193 * resched_task - mark a task 'to be rescheduled now'.
1195 * On UP this means the setting of the need_resched flag, on SMP it
1196 * might also involve a cross-CPU call to trigger the scheduler on
1201 #ifndef tsk_is_polling
1202 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1205 static void resched_task(struct task_struct
*p
)
1209 assert_spin_locked(&task_rq(p
)->lock
);
1211 if (test_tsk_need_resched(p
))
1214 set_tsk_need_resched(p
);
1217 if (cpu
== smp_processor_id())
1220 /* NEED_RESCHED must be visible before we test polling */
1222 if (!tsk_is_polling(p
))
1223 smp_send_reschedule(cpu
);
1226 static void resched_cpu(int cpu
)
1228 struct rq
*rq
= cpu_rq(cpu
);
1229 unsigned long flags
;
1231 if (!spin_trylock_irqsave(&rq
->lock
, flags
))
1233 resched_task(cpu_curr(cpu
));
1234 spin_unlock_irqrestore(&rq
->lock
, flags
);
1239 * When add_timer_on() enqueues a timer into the timer wheel of an
1240 * idle CPU then this timer might expire before the next timer event
1241 * which is scheduled to wake up that CPU. In case of a completely
1242 * idle system the next event might even be infinite time into the
1243 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1244 * leaves the inner idle loop so the newly added timer is taken into
1245 * account when the CPU goes back to idle and evaluates the timer
1246 * wheel for the next timer event.
1248 void wake_up_idle_cpu(int cpu
)
1250 struct rq
*rq
= cpu_rq(cpu
);
1252 if (cpu
== smp_processor_id())
1256 * This is safe, as this function is called with the timer
1257 * wheel base lock of (cpu) held. When the CPU is on the way
1258 * to idle and has not yet set rq->curr to idle then it will
1259 * be serialized on the timer wheel base lock and take the new
1260 * timer into account automatically.
1262 if (rq
->curr
!= rq
->idle
)
1266 * We can set TIF_RESCHED on the idle task of the other CPU
1267 * lockless. The worst case is that the other CPU runs the
1268 * idle task through an additional NOOP schedule()
1270 set_tsk_need_resched(rq
->idle
);
1272 /* NEED_RESCHED must be visible before we test polling */
1274 if (!tsk_is_polling(rq
->idle
))
1275 smp_send_reschedule(cpu
);
1277 #endif /* CONFIG_NO_HZ */
1279 #else /* !CONFIG_SMP */
1280 static void resched_task(struct task_struct
*p
)
1282 assert_spin_locked(&task_rq(p
)->lock
);
1283 set_tsk_need_resched(p
);
1285 #endif /* CONFIG_SMP */
1287 #if BITS_PER_LONG == 32
1288 # define WMULT_CONST (~0UL)
1290 # define WMULT_CONST (1UL << 32)
1293 #define WMULT_SHIFT 32
1296 * Shift right and round:
1298 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1301 * delta *= weight / lw
1303 static unsigned long
1304 calc_delta_mine(unsigned long delta_exec
, unsigned long weight
,
1305 struct load_weight
*lw
)
1309 if (!lw
->inv_weight
) {
1310 if (BITS_PER_LONG
> 32 && unlikely(lw
->weight
>= WMULT_CONST
))
1313 lw
->inv_weight
= 1 + (WMULT_CONST
-lw
->weight
/2)
1317 tmp
= (u64
)delta_exec
* weight
;
1319 * Check whether we'd overflow the 64-bit multiplication:
1321 if (unlikely(tmp
> WMULT_CONST
))
1322 tmp
= SRR(SRR(tmp
, WMULT_SHIFT
/2) * lw
->inv_weight
,
1325 tmp
= SRR(tmp
* lw
->inv_weight
, WMULT_SHIFT
);
1327 return (unsigned long)min(tmp
, (u64
)(unsigned long)LONG_MAX
);
1330 static inline void update_load_add(struct load_weight
*lw
, unsigned long inc
)
1336 static inline void update_load_sub(struct load_weight
*lw
, unsigned long dec
)
1343 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1344 * of tasks with abnormal "nice" values across CPUs the contribution that
1345 * each task makes to its run queue's load is weighted according to its
1346 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1347 * scaled version of the new time slice allocation that they receive on time
1351 #define WEIGHT_IDLEPRIO 3
1352 #define WMULT_IDLEPRIO 1431655765
1355 * Nice levels are multiplicative, with a gentle 10% change for every
1356 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1357 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1358 * that remained on nice 0.
1360 * The "10% effect" is relative and cumulative: from _any_ nice level,
1361 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1362 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1363 * If a task goes up by ~10% and another task goes down by ~10% then
1364 * the relative distance between them is ~25%.)
1366 static const int prio_to_weight
[40] = {
1367 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1368 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1369 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1370 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1371 /* 0 */ 1024, 820, 655, 526, 423,
1372 /* 5 */ 335, 272, 215, 172, 137,
1373 /* 10 */ 110, 87, 70, 56, 45,
1374 /* 15 */ 36, 29, 23, 18, 15,
1378 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1380 * In cases where the weight does not change often, we can use the
1381 * precalculated inverse to speed up arithmetics by turning divisions
1382 * into multiplications:
1384 static const u32 prio_to_wmult
[40] = {
1385 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1386 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1387 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1388 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1389 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1390 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1391 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1392 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1395 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
);
1398 * runqueue iterator, to support SMP load-balancing between different
1399 * scheduling classes, without having to expose their internal data
1400 * structures to the load-balancing proper:
1402 struct rq_iterator
{
1404 struct task_struct
*(*start
)(void *);
1405 struct task_struct
*(*next
)(void *);
1409 static unsigned long
1410 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
1411 unsigned long max_load_move
, struct sched_domain
*sd
,
1412 enum cpu_idle_type idle
, int *all_pinned
,
1413 int *this_best_prio
, struct rq_iterator
*iterator
);
1416 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
1417 struct sched_domain
*sd
, enum cpu_idle_type idle
,
1418 struct rq_iterator
*iterator
);
1421 /* Time spent by the tasks of the cpu accounting group executing in ... */
1422 enum cpuacct_stat_index
{
1423 CPUACCT_STAT_USER
, /* ... user mode */
1424 CPUACCT_STAT_SYSTEM
, /* ... kernel mode */
1426 CPUACCT_STAT_NSTATS
,
1429 #ifdef CONFIG_CGROUP_CPUACCT
1430 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
);
1431 static void cpuacct_update_stats(struct task_struct
*tsk
,
1432 enum cpuacct_stat_index idx
, cputime_t val
);
1434 static inline void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
) {}
1435 static inline void cpuacct_update_stats(struct task_struct
*tsk
,
1436 enum cpuacct_stat_index idx
, cputime_t val
) {}
1439 static inline void inc_cpu_load(struct rq
*rq
, unsigned long load
)
1441 update_load_add(&rq
->load
, load
);
1444 static inline void dec_cpu_load(struct rq
*rq
, unsigned long load
)
1446 update_load_sub(&rq
->load
, load
);
1449 #if (defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)) || defined(CONFIG_RT_GROUP_SCHED)
1450 typedef int (*tg_visitor
)(struct task_group
*, void *);
1453 * Iterate the full tree, calling @down when first entering a node and @up when
1454 * leaving it for the final time.
1456 static int walk_tg_tree(tg_visitor down
, tg_visitor up
, void *data
)
1458 struct task_group
*parent
, *child
;
1462 parent
= &root_task_group
;
1464 ret
= (*down
)(parent
, data
);
1467 list_for_each_entry_rcu(child
, &parent
->children
, siblings
) {
1474 ret
= (*up
)(parent
, data
);
1479 parent
= parent
->parent
;
1488 static int tg_nop(struct task_group
*tg
, void *data
)
1495 static unsigned long source_load(int cpu
, int type
);
1496 static unsigned long target_load(int cpu
, int type
);
1497 static int task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
);
1499 static unsigned long cpu_avg_load_per_task(int cpu
)
1501 struct rq
*rq
= cpu_rq(cpu
);
1502 unsigned long nr_running
= ACCESS_ONCE(rq
->nr_running
);
1505 rq
->avg_load_per_task
= rq
->load
.weight
/ nr_running
;
1507 rq
->avg_load_per_task
= 0;
1509 return rq
->avg_load_per_task
;
1512 #ifdef CONFIG_FAIR_GROUP_SCHED
1514 static void __set_se_shares(struct sched_entity
*se
, unsigned long shares
);
1517 * Calculate and set the cpu's group shares.
1520 update_group_shares_cpu(struct task_group
*tg
, int cpu
,
1521 unsigned long sd_shares
, unsigned long sd_rq_weight
)
1523 unsigned long shares
;
1524 unsigned long rq_weight
;
1529 rq_weight
= tg
->cfs_rq
[cpu
]->rq_weight
;
1532 * \Sum shares * rq_weight
1533 * shares = -----------------------
1537 shares
= (sd_shares
* rq_weight
) / sd_rq_weight
;
1538 shares
= clamp_t(unsigned long, shares
, MIN_SHARES
, MAX_SHARES
);
1540 if (abs(shares
- tg
->se
[cpu
]->load
.weight
) >
1541 sysctl_sched_shares_thresh
) {
1542 struct rq
*rq
= cpu_rq(cpu
);
1543 unsigned long flags
;
1545 spin_lock_irqsave(&rq
->lock
, flags
);
1546 tg
->cfs_rq
[cpu
]->shares
= shares
;
1548 __set_se_shares(tg
->se
[cpu
], shares
);
1549 spin_unlock_irqrestore(&rq
->lock
, flags
);
1554 * Re-compute the task group their per cpu shares over the given domain.
1555 * This needs to be done in a bottom-up fashion because the rq weight of a
1556 * parent group depends on the shares of its child groups.
1558 static int tg_shares_up(struct task_group
*tg
, void *data
)
1560 unsigned long weight
, rq_weight
= 0;
1561 unsigned long shares
= 0;
1562 struct sched_domain
*sd
= data
;
1565 for_each_cpu(i
, sched_domain_span(sd
)) {
1567 * If there are currently no tasks on the cpu pretend there
1568 * is one of average load so that when a new task gets to
1569 * run here it will not get delayed by group starvation.
1571 weight
= tg
->cfs_rq
[i
]->load
.weight
;
1573 weight
= NICE_0_LOAD
;
1575 tg
->cfs_rq
[i
]->rq_weight
= weight
;
1576 rq_weight
+= weight
;
1577 shares
+= tg
->cfs_rq
[i
]->shares
;
1580 if ((!shares
&& rq_weight
) || shares
> tg
->shares
)
1581 shares
= tg
->shares
;
1583 if (!sd
->parent
|| !(sd
->parent
->flags
& SD_LOAD_BALANCE
))
1584 shares
= tg
->shares
;
1586 for_each_cpu(i
, sched_domain_span(sd
))
1587 update_group_shares_cpu(tg
, i
, shares
, rq_weight
);
1593 * Compute the cpu's hierarchical load factor for each task group.
1594 * This needs to be done in a top-down fashion because the load of a child
1595 * group is a fraction of its parents load.
1597 static int tg_load_down(struct task_group
*tg
, void *data
)
1600 long cpu
= (long)data
;
1603 load
= cpu_rq(cpu
)->load
.weight
;
1605 load
= tg
->parent
->cfs_rq
[cpu
]->h_load
;
1606 load
*= tg
->cfs_rq
[cpu
]->shares
;
1607 load
/= tg
->parent
->cfs_rq
[cpu
]->load
.weight
+ 1;
1610 tg
->cfs_rq
[cpu
]->h_load
= load
;
1615 static void update_shares(struct sched_domain
*sd
)
1617 u64 now
= cpu_clock(raw_smp_processor_id());
1618 s64 elapsed
= now
- sd
->last_update
;
1620 if (elapsed
>= (s64
)(u64
)sysctl_sched_shares_ratelimit
) {
1621 sd
->last_update
= now
;
1622 walk_tg_tree(tg_nop
, tg_shares_up
, sd
);
1626 static void update_shares_locked(struct rq
*rq
, struct sched_domain
*sd
)
1628 spin_unlock(&rq
->lock
);
1630 spin_lock(&rq
->lock
);
1633 static void update_h_load(long cpu
)
1635 walk_tg_tree(tg_load_down
, tg_nop
, (void *)cpu
);
1640 static inline void update_shares(struct sched_domain
*sd
)
1644 static inline void update_shares_locked(struct rq
*rq
, struct sched_domain
*sd
)
1650 #ifdef CONFIG_PREEMPT
1653 * fair double_lock_balance: Safely acquires both rq->locks in a fair
1654 * way at the expense of forcing extra atomic operations in all
1655 * invocations. This assures that the double_lock is acquired using the
1656 * same underlying policy as the spinlock_t on this architecture, which
1657 * reduces latency compared to the unfair variant below. However, it
1658 * also adds more overhead and therefore may reduce throughput.
1660 static inline int _double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1661 __releases(this_rq
->lock
)
1662 __acquires(busiest
->lock
)
1663 __acquires(this_rq
->lock
)
1665 spin_unlock(&this_rq
->lock
);
1666 double_rq_lock(this_rq
, busiest
);
1673 * Unfair double_lock_balance: Optimizes throughput at the expense of
1674 * latency by eliminating extra atomic operations when the locks are
1675 * already in proper order on entry. This favors lower cpu-ids and will
1676 * grant the double lock to lower cpus over higher ids under contention,
1677 * regardless of entry order into the function.
1679 static int _double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1680 __releases(this_rq
->lock
)
1681 __acquires(busiest
->lock
)
1682 __acquires(this_rq
->lock
)
1686 if (unlikely(!spin_trylock(&busiest
->lock
))) {
1687 if (busiest
< this_rq
) {
1688 spin_unlock(&this_rq
->lock
);
1689 spin_lock(&busiest
->lock
);
1690 spin_lock_nested(&this_rq
->lock
, SINGLE_DEPTH_NESTING
);
1693 spin_lock_nested(&busiest
->lock
, SINGLE_DEPTH_NESTING
);
1698 #endif /* CONFIG_PREEMPT */
1701 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
1703 static int double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1705 if (unlikely(!irqs_disabled())) {
1706 /* printk() doesn't work good under rq->lock */
1707 spin_unlock(&this_rq
->lock
);
1711 return _double_lock_balance(this_rq
, busiest
);
1714 static inline void double_unlock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1715 __releases(busiest
->lock
)
1717 spin_unlock(&busiest
->lock
);
1718 lock_set_subclass(&this_rq
->lock
.dep_map
, 0, _RET_IP_
);
1722 #ifdef CONFIG_FAIR_GROUP_SCHED
1723 static void cfs_rq_set_shares(struct cfs_rq
*cfs_rq
, unsigned long shares
)
1726 cfs_rq
->shares
= shares
;
1731 #include "sched_stats.h"
1732 #include "sched_idletask.c"
1733 #include "sched_fair.c"
1734 #include "sched_rt.c"
1735 #ifdef CONFIG_SCHED_DEBUG
1736 # include "sched_debug.c"
1739 #define sched_class_highest (&rt_sched_class)
1740 #define for_each_class(class) \
1741 for (class = sched_class_highest; class; class = class->next)
1743 static void inc_nr_running(struct rq
*rq
)
1748 static void dec_nr_running(struct rq
*rq
)
1753 static void set_load_weight(struct task_struct
*p
)
1755 if (task_has_rt_policy(p
)) {
1756 p
->se
.load
.weight
= prio_to_weight
[0] * 2;
1757 p
->se
.load
.inv_weight
= prio_to_wmult
[0] >> 1;
1762 * SCHED_IDLE tasks get minimal weight:
1764 if (p
->policy
== SCHED_IDLE
) {
1765 p
->se
.load
.weight
= WEIGHT_IDLEPRIO
;
1766 p
->se
.load
.inv_weight
= WMULT_IDLEPRIO
;
1770 p
->se
.load
.weight
= prio_to_weight
[p
->static_prio
- MAX_RT_PRIO
];
1771 p
->se
.load
.inv_weight
= prio_to_wmult
[p
->static_prio
- MAX_RT_PRIO
];
1774 static void update_avg(u64
*avg
, u64 sample
)
1776 s64 diff
= sample
- *avg
;
1780 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1783 p
->se
.start_runtime
= p
->se
.sum_exec_runtime
;
1785 sched_info_queued(p
);
1786 p
->sched_class
->enqueue_task(rq
, p
, wakeup
);
1790 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1793 if (p
->se
.last_wakeup
) {
1794 update_avg(&p
->se
.avg_overlap
,
1795 p
->se
.sum_exec_runtime
- p
->se
.last_wakeup
);
1796 p
->se
.last_wakeup
= 0;
1798 update_avg(&p
->se
.avg_wakeup
,
1799 sysctl_sched_wakeup_granularity
);
1803 sched_info_dequeued(p
);
1804 p
->sched_class
->dequeue_task(rq
, p
, sleep
);
1809 * __normal_prio - return the priority that is based on the static prio
1811 static inline int __normal_prio(struct task_struct
*p
)
1813 return p
->static_prio
;
1817 * Calculate the expected normal priority: i.e. priority
1818 * without taking RT-inheritance into account. Might be
1819 * boosted by interactivity modifiers. Changes upon fork,
1820 * setprio syscalls, and whenever the interactivity
1821 * estimator recalculates.
1823 static inline int normal_prio(struct task_struct
*p
)
1827 if (task_has_rt_policy(p
))
1828 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
1830 prio
= __normal_prio(p
);
1835 * Calculate the current priority, i.e. the priority
1836 * taken into account by the scheduler. This value might
1837 * be boosted by RT tasks, or might be boosted by
1838 * interactivity modifiers. Will be RT if the task got
1839 * RT-boosted. If not then it returns p->normal_prio.
1841 static int effective_prio(struct task_struct
*p
)
1843 p
->normal_prio
= normal_prio(p
);
1845 * If we are RT tasks or we were boosted to RT priority,
1846 * keep the priority unchanged. Otherwise, update priority
1847 * to the normal priority:
1849 if (!rt_prio(p
->prio
))
1850 return p
->normal_prio
;
1855 * activate_task - move a task to the runqueue.
1857 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1859 if (task_contributes_to_load(p
))
1860 rq
->nr_uninterruptible
--;
1862 enqueue_task(rq
, p
, wakeup
);
1867 * deactivate_task - remove a task from the runqueue.
1869 static void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1871 if (task_contributes_to_load(p
))
1872 rq
->nr_uninterruptible
++;
1874 dequeue_task(rq
, p
, sleep
);
1879 * task_curr - is this task currently executing on a CPU?
1880 * @p: the task in question.
1882 inline int task_curr(const struct task_struct
*p
)
1884 return cpu_curr(task_cpu(p
)) == p
;
1887 static inline void __set_task_cpu(struct task_struct
*p
, unsigned int cpu
)
1889 set_task_rq(p
, cpu
);
1892 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1893 * successfuly executed on another CPU. We must ensure that updates of
1894 * per-task data have been completed by this moment.
1897 task_thread_info(p
)->cpu
= cpu
;
1901 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
1902 const struct sched_class
*prev_class
,
1903 int oldprio
, int running
)
1905 if (prev_class
!= p
->sched_class
) {
1906 if (prev_class
->switched_from
)
1907 prev_class
->switched_from(rq
, p
, running
);
1908 p
->sched_class
->switched_to(rq
, p
, running
);
1910 p
->sched_class
->prio_changed(rq
, p
, oldprio
, running
);
1915 /* Used instead of source_load when we know the type == 0 */
1916 static unsigned long weighted_cpuload(const int cpu
)
1918 return cpu_rq(cpu
)->load
.weight
;
1922 * Is this task likely cache-hot:
1925 task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
)
1930 * Buddy candidates are cache hot:
1932 if (sched_feat(CACHE_HOT_BUDDY
) &&
1933 (&p
->se
== cfs_rq_of(&p
->se
)->next
||
1934 &p
->se
== cfs_rq_of(&p
->se
)->last
))
1937 if (p
->sched_class
!= &fair_sched_class
)
1940 if (sysctl_sched_migration_cost
== -1)
1942 if (sysctl_sched_migration_cost
== 0)
1945 delta
= now
- p
->se
.exec_start
;
1947 return delta
< (s64
)sysctl_sched_migration_cost
;
1951 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
1953 int old_cpu
= task_cpu(p
);
1954 struct rq
*old_rq
= cpu_rq(old_cpu
), *new_rq
= cpu_rq(new_cpu
);
1955 struct cfs_rq
*old_cfsrq
= task_cfs_rq(p
),
1956 *new_cfsrq
= cpu_cfs_rq(old_cfsrq
, new_cpu
);
1959 clock_offset
= old_rq
->clock
- new_rq
->clock
;
1961 trace_sched_migrate_task(p
, task_cpu(p
), new_cpu
);
1963 #ifdef CONFIG_SCHEDSTATS
1964 if (p
->se
.wait_start
)
1965 p
->se
.wait_start
-= clock_offset
;
1966 if (p
->se
.sleep_start
)
1967 p
->se
.sleep_start
-= clock_offset
;
1968 if (p
->se
.block_start
)
1969 p
->se
.block_start
-= clock_offset
;
1970 if (old_cpu
!= new_cpu
) {
1971 schedstat_inc(p
, se
.nr_migrations
);
1972 if (task_hot(p
, old_rq
->clock
, NULL
))
1973 schedstat_inc(p
, se
.nr_forced2_migrations
);
1976 p
->se
.vruntime
-= old_cfsrq
->min_vruntime
-
1977 new_cfsrq
->min_vruntime
;
1979 __set_task_cpu(p
, new_cpu
);
1982 struct migration_req
{
1983 struct list_head list
;
1985 struct task_struct
*task
;
1988 struct completion done
;
1992 * The task's runqueue lock must be held.
1993 * Returns true if you have to wait for migration thread.
1996 migrate_task(struct task_struct
*p
, int dest_cpu
, struct migration_req
*req
)
1998 struct rq
*rq
= task_rq(p
);
2001 * If the task is not on a runqueue (and not running), then
2002 * it is sufficient to simply update the task's cpu field.
2004 if (!p
->se
.on_rq
&& !task_running(rq
, p
)) {
2005 set_task_cpu(p
, dest_cpu
);
2009 init_completion(&req
->done
);
2011 req
->dest_cpu
= dest_cpu
;
2012 list_add(&req
->list
, &rq
->migration_queue
);
2018 * wait_task_inactive - wait for a thread to unschedule.
2020 * If @match_state is nonzero, it's the @p->state value just checked and
2021 * not expected to change. If it changes, i.e. @p might have woken up,
2022 * then return zero. When we succeed in waiting for @p to be off its CPU,
2023 * we return a positive number (its total switch count). If a second call
2024 * a short while later returns the same number, the caller can be sure that
2025 * @p has remained unscheduled the whole time.
2027 * The caller must ensure that the task *will* unschedule sometime soon,
2028 * else this function might spin for a *long* time. This function can't
2029 * be called with interrupts off, or it may introduce deadlock with
2030 * smp_call_function() if an IPI is sent by the same process we are
2031 * waiting to become inactive.
2033 unsigned long wait_task_inactive(struct task_struct
*p
, long match_state
)
2035 unsigned long flags
;
2042 * We do the initial early heuristics without holding
2043 * any task-queue locks at all. We'll only try to get
2044 * the runqueue lock when things look like they will
2050 * If the task is actively running on another CPU
2051 * still, just relax and busy-wait without holding
2054 * NOTE! Since we don't hold any locks, it's not
2055 * even sure that "rq" stays as the right runqueue!
2056 * But we don't care, since "task_running()" will
2057 * return false if the runqueue has changed and p
2058 * is actually now running somewhere else!
2060 while (task_running(rq
, p
)) {
2061 if (match_state
&& unlikely(p
->state
!= match_state
))
2067 * Ok, time to look more closely! We need the rq
2068 * lock now, to be *sure*. If we're wrong, we'll
2069 * just go back and repeat.
2071 rq
= task_rq_lock(p
, &flags
);
2072 trace_sched_wait_task(rq
, p
);
2073 running
= task_running(rq
, p
);
2074 on_rq
= p
->se
.on_rq
;
2076 if (!match_state
|| p
->state
== match_state
)
2077 ncsw
= p
->nvcsw
| LONG_MIN
; /* sets MSB */
2078 task_rq_unlock(rq
, &flags
);
2081 * If it changed from the expected state, bail out now.
2083 if (unlikely(!ncsw
))
2087 * Was it really running after all now that we
2088 * checked with the proper locks actually held?
2090 * Oops. Go back and try again..
2092 if (unlikely(running
)) {
2098 * It's not enough that it's not actively running,
2099 * it must be off the runqueue _entirely_, and not
2102 * So if it was still runnable (but just not actively
2103 * running right now), it's preempted, and we should
2104 * yield - it could be a while.
2106 if (unlikely(on_rq
)) {
2107 schedule_timeout_uninterruptible(1);
2112 * Ahh, all good. It wasn't running, and it wasn't
2113 * runnable, which means that it will never become
2114 * running in the future either. We're all done!
2123 * kick_process - kick a running thread to enter/exit the kernel
2124 * @p: the to-be-kicked thread
2126 * Cause a process which is running on another CPU to enter
2127 * kernel-mode, without any delay. (to get signals handled.)
2129 * NOTE: this function doesnt have to take the runqueue lock,
2130 * because all it wants to ensure is that the remote task enters
2131 * the kernel. If the IPI races and the task has been migrated
2132 * to another CPU then no harm is done and the purpose has been
2135 void kick_process(struct task_struct
*p
)
2141 if ((cpu
!= smp_processor_id()) && task_curr(p
))
2142 smp_send_reschedule(cpu
);
2147 * Return a low guess at the load of a migration-source cpu weighted
2148 * according to the scheduling class and "nice" value.
2150 * We want to under-estimate the load of migration sources, to
2151 * balance conservatively.
2153 static unsigned long source_load(int cpu
, int type
)
2155 struct rq
*rq
= cpu_rq(cpu
);
2156 unsigned long total
= weighted_cpuload(cpu
);
2158 if (type
== 0 || !sched_feat(LB_BIAS
))
2161 return min(rq
->cpu_load
[type
-1], total
);
2165 * Return a high guess at the load of a migration-target cpu weighted
2166 * according to the scheduling class and "nice" value.
2168 static unsigned long target_load(int cpu
, int type
)
2170 struct rq
*rq
= cpu_rq(cpu
);
2171 unsigned long total
= weighted_cpuload(cpu
);
2173 if (type
== 0 || !sched_feat(LB_BIAS
))
2176 return max(rq
->cpu_load
[type
-1], total
);
2180 * find_idlest_group finds and returns the least busy CPU group within the
2183 static struct sched_group
*
2184 find_idlest_group(struct sched_domain
*sd
, struct task_struct
*p
, int this_cpu
)
2186 struct sched_group
*idlest
= NULL
, *this = NULL
, *group
= sd
->groups
;
2187 unsigned long min_load
= ULONG_MAX
, this_load
= 0;
2188 int load_idx
= sd
->forkexec_idx
;
2189 int imbalance
= 100 + (sd
->imbalance_pct
-100)/2;
2192 unsigned long load
, avg_load
;
2196 /* Skip over this group if it has no CPUs allowed */
2197 if (!cpumask_intersects(sched_group_cpus(group
),
2201 local_group
= cpumask_test_cpu(this_cpu
,
2202 sched_group_cpus(group
));
2204 /* Tally up the load of all CPUs in the group */
2207 for_each_cpu(i
, sched_group_cpus(group
)) {
2208 /* Bias balancing toward cpus of our domain */
2210 load
= source_load(i
, load_idx
);
2212 load
= target_load(i
, load_idx
);
2217 /* Adjust by relative CPU power of the group */
2218 avg_load
= sg_div_cpu_power(group
,
2219 avg_load
* SCHED_LOAD_SCALE
);
2222 this_load
= avg_load
;
2224 } else if (avg_load
< min_load
) {
2225 min_load
= avg_load
;
2228 } while (group
= group
->next
, group
!= sd
->groups
);
2230 if (!idlest
|| 100*this_load
< imbalance
*min_load
)
2236 * find_idlest_cpu - find the idlest cpu among the cpus in group.
2239 find_idlest_cpu(struct sched_group
*group
, struct task_struct
*p
, int this_cpu
)
2241 unsigned long load
, min_load
= ULONG_MAX
;
2245 /* Traverse only the allowed CPUs */
2246 for_each_cpu_and(i
, sched_group_cpus(group
), &p
->cpus_allowed
) {
2247 load
= weighted_cpuload(i
);
2249 if (load
< min_load
|| (load
== min_load
&& i
== this_cpu
)) {
2259 * sched_balance_self: balance the current task (running on cpu) in domains
2260 * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
2263 * Balance, ie. select the least loaded group.
2265 * Returns the target CPU number, or the same CPU if no balancing is needed.
2267 * preempt must be disabled.
2269 static int sched_balance_self(int cpu
, int flag
)
2271 struct task_struct
*t
= current
;
2272 struct sched_domain
*tmp
, *sd
= NULL
;
2274 for_each_domain(cpu
, tmp
) {
2276 * If power savings logic is enabled for a domain, stop there.
2278 if (tmp
->flags
& SD_POWERSAVINGS_BALANCE
)
2280 if (tmp
->flags
& flag
)
2288 struct sched_group
*group
;
2289 int new_cpu
, weight
;
2291 if (!(sd
->flags
& flag
)) {
2296 group
= find_idlest_group(sd
, t
, cpu
);
2302 new_cpu
= find_idlest_cpu(group
, t
, cpu
);
2303 if (new_cpu
== -1 || new_cpu
== cpu
) {
2304 /* Now try balancing at a lower domain level of cpu */
2309 /* Now try balancing at a lower domain level of new_cpu */
2311 weight
= cpumask_weight(sched_domain_span(sd
));
2313 for_each_domain(cpu
, tmp
) {
2314 if (weight
<= cpumask_weight(sched_domain_span(tmp
)))
2316 if (tmp
->flags
& flag
)
2319 /* while loop will break here if sd == NULL */
2325 #endif /* CONFIG_SMP */
2328 * try_to_wake_up - wake up a thread
2329 * @p: the to-be-woken-up thread
2330 * @state: the mask of task states that can be woken
2331 * @sync: do a synchronous wakeup?
2333 * Put it on the run-queue if it's not already there. The "current"
2334 * thread is always on the run-queue (except when the actual
2335 * re-schedule is in progress), and as such you're allowed to do
2336 * the simpler "current->state = TASK_RUNNING" to mark yourself
2337 * runnable without the overhead of this.
2339 * returns failure only if the task is already active.
2341 static int try_to_wake_up(struct task_struct
*p
, unsigned int state
, int sync
)
2343 int cpu
, orig_cpu
, this_cpu
, success
= 0;
2344 unsigned long flags
;
2348 if (!sched_feat(SYNC_WAKEUPS
))
2352 if (sched_feat(LB_WAKEUP_UPDATE
) && !root_task_group_empty()) {
2353 struct sched_domain
*sd
;
2355 this_cpu
= raw_smp_processor_id();
2358 for_each_domain(this_cpu
, sd
) {
2359 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
2368 rq
= task_rq_lock(p
, &flags
);
2369 update_rq_clock(rq
);
2370 old_state
= p
->state
;
2371 if (!(old_state
& state
))
2379 this_cpu
= smp_processor_id();
2382 if (unlikely(task_running(rq
, p
)))
2385 cpu
= p
->sched_class
->select_task_rq(p
, sync
);
2386 if (cpu
!= orig_cpu
) {
2387 set_task_cpu(p
, cpu
);
2388 task_rq_unlock(rq
, &flags
);
2389 /* might preempt at this point */
2390 rq
= task_rq_lock(p
, &flags
);
2391 old_state
= p
->state
;
2392 if (!(old_state
& state
))
2397 this_cpu
= smp_processor_id();
2401 #ifdef CONFIG_SCHEDSTATS
2402 schedstat_inc(rq
, ttwu_count
);
2403 if (cpu
== this_cpu
)
2404 schedstat_inc(rq
, ttwu_local
);
2406 struct sched_domain
*sd
;
2407 for_each_domain(this_cpu
, sd
) {
2408 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
2409 schedstat_inc(sd
, ttwu_wake_remote
);
2414 #endif /* CONFIG_SCHEDSTATS */
2417 #endif /* CONFIG_SMP */
2418 schedstat_inc(p
, se
.nr_wakeups
);
2420 schedstat_inc(p
, se
.nr_wakeups_sync
);
2421 if (orig_cpu
!= cpu
)
2422 schedstat_inc(p
, se
.nr_wakeups_migrate
);
2423 if (cpu
== this_cpu
)
2424 schedstat_inc(p
, se
.nr_wakeups_local
);
2426 schedstat_inc(p
, se
.nr_wakeups_remote
);
2427 activate_task(rq
, p
, 1);
2431 * Only attribute actual wakeups done by this task.
2433 if (!in_interrupt()) {
2434 struct sched_entity
*se
= ¤t
->se
;
2435 u64 sample
= se
->sum_exec_runtime
;
2437 if (se
->last_wakeup
)
2438 sample
-= se
->last_wakeup
;
2440 sample
-= se
->start_runtime
;
2441 update_avg(&se
->avg_wakeup
, sample
);
2443 se
->last_wakeup
= se
->sum_exec_runtime
;
2447 trace_sched_wakeup(rq
, p
, success
);
2448 check_preempt_curr(rq
, p
, sync
);
2450 p
->state
= TASK_RUNNING
;
2452 if (p
->sched_class
->task_wake_up
)
2453 p
->sched_class
->task_wake_up(rq
, p
);
2456 task_rq_unlock(rq
, &flags
);
2461 int wake_up_process(struct task_struct
*p
)
2463 return try_to_wake_up(p
, TASK_ALL
, 0);
2465 EXPORT_SYMBOL(wake_up_process
);
2467 int wake_up_state(struct task_struct
*p
, unsigned int state
)
2469 return try_to_wake_up(p
, state
, 0);
2473 * Perform scheduler related setup for a newly forked process p.
2474 * p is forked by current.
2476 * __sched_fork() is basic setup used by init_idle() too:
2478 static void __sched_fork(struct task_struct
*p
)
2480 p
->se
.exec_start
= 0;
2481 p
->se
.sum_exec_runtime
= 0;
2482 p
->se
.prev_sum_exec_runtime
= 0;
2483 p
->se
.last_wakeup
= 0;
2484 p
->se
.avg_overlap
= 0;
2485 p
->se
.start_runtime
= 0;
2486 p
->se
.avg_wakeup
= sysctl_sched_wakeup_granularity
;
2488 #ifdef CONFIG_SCHEDSTATS
2489 p
->se
.wait_start
= 0;
2490 p
->se
.sum_sleep_runtime
= 0;
2491 p
->se
.sleep_start
= 0;
2492 p
->se
.block_start
= 0;
2493 p
->se
.sleep_max
= 0;
2494 p
->se
.block_max
= 0;
2496 p
->se
.slice_max
= 0;
2500 INIT_LIST_HEAD(&p
->rt
.run_list
);
2502 INIT_LIST_HEAD(&p
->se
.group_node
);
2504 #ifdef CONFIG_PREEMPT_NOTIFIERS
2505 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
2509 * We mark the process as running here, but have not actually
2510 * inserted it onto the runqueue yet. This guarantees that
2511 * nobody will actually run it, and a signal or other external
2512 * event cannot wake it up and insert it on the runqueue either.
2514 p
->state
= TASK_RUNNING
;
2518 * fork()/clone()-time setup:
2520 void sched_fork(struct task_struct
*p
, int clone_flags
)
2522 int cpu
= get_cpu();
2527 cpu
= sched_balance_self(cpu
, SD_BALANCE_FORK
);
2529 set_task_cpu(p
, cpu
);
2532 * Make sure we do not leak PI boosting priority to the child:
2534 p
->prio
= current
->normal_prio
;
2535 if (!rt_prio(p
->prio
))
2536 p
->sched_class
= &fair_sched_class
;
2538 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2539 if (likely(sched_info_on()))
2540 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
2542 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
2545 #ifdef CONFIG_PREEMPT
2546 /* Want to start with kernel preemption disabled. */
2547 task_thread_info(p
)->preempt_count
= 1;
2549 plist_node_init(&p
->pushable_tasks
, MAX_PRIO
);
2555 * wake_up_new_task - wake up a newly created task for the first time.
2557 * This function will do some initial scheduler statistics housekeeping
2558 * that must be done for every newly created context, then puts the task
2559 * on the runqueue and wakes it.
2561 void wake_up_new_task(struct task_struct
*p
, unsigned long clone_flags
)
2563 unsigned long flags
;
2566 rq
= task_rq_lock(p
, &flags
);
2567 BUG_ON(p
->state
!= TASK_RUNNING
);
2568 update_rq_clock(rq
);
2570 p
->prio
= effective_prio(p
);
2572 if (!p
->sched_class
->task_new
|| !current
->se
.on_rq
) {
2573 activate_task(rq
, p
, 0);
2576 * Let the scheduling class do new task startup
2577 * management (if any):
2579 p
->sched_class
->task_new(rq
, p
);
2582 trace_sched_wakeup_new(rq
, p
, 1);
2583 check_preempt_curr(rq
, p
, 0);
2585 if (p
->sched_class
->task_wake_up
)
2586 p
->sched_class
->task_wake_up(rq
, p
);
2588 task_rq_unlock(rq
, &flags
);
2591 #ifdef CONFIG_PREEMPT_NOTIFIERS
2594 * preempt_notifier_register - tell me when current is being preempted & rescheduled
2595 * @notifier: notifier struct to register
2597 void preempt_notifier_register(struct preempt_notifier
*notifier
)
2599 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
2601 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
2604 * preempt_notifier_unregister - no longer interested in preemption notifications
2605 * @notifier: notifier struct to unregister
2607 * This is safe to call from within a preemption notifier.
2609 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
2611 hlist_del(¬ifier
->link
);
2613 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
2615 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2617 struct preempt_notifier
*notifier
;
2618 struct hlist_node
*node
;
2620 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2621 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
2625 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2626 struct task_struct
*next
)
2628 struct preempt_notifier
*notifier
;
2629 struct hlist_node
*node
;
2631 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2632 notifier
->ops
->sched_out(notifier
, next
);
2635 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2637 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2642 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2643 struct task_struct
*next
)
2647 #endif /* CONFIG_PREEMPT_NOTIFIERS */
2650 * prepare_task_switch - prepare to switch tasks
2651 * @rq: the runqueue preparing to switch
2652 * @prev: the current task that is being switched out
2653 * @next: the task we are going to switch to.
2655 * This is called with the rq lock held and interrupts off. It must
2656 * be paired with a subsequent finish_task_switch after the context
2659 * prepare_task_switch sets up locking and calls architecture specific
2663 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
2664 struct task_struct
*next
)
2666 fire_sched_out_preempt_notifiers(prev
, next
);
2667 prepare_lock_switch(rq
, next
);
2668 prepare_arch_switch(next
);
2672 * finish_task_switch - clean up after a task-switch
2673 * @rq: runqueue associated with task-switch
2674 * @prev: the thread we just switched away from.
2676 * finish_task_switch must be called after the context switch, paired
2677 * with a prepare_task_switch call before the context switch.
2678 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2679 * and do any other architecture-specific cleanup actions.
2681 * Note that we may have delayed dropping an mm in context_switch(). If
2682 * so, we finish that here outside of the runqueue lock. (Doing it
2683 * with the lock held can cause deadlocks; see schedule() for
2686 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
2687 __releases(rq
->lock
)
2689 struct mm_struct
*mm
= rq
->prev_mm
;
2692 int post_schedule
= 0;
2694 if (current
->sched_class
->needs_post_schedule
)
2695 post_schedule
= current
->sched_class
->needs_post_schedule(rq
);
2701 * A task struct has one reference for the use as "current".
2702 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2703 * schedule one last time. The schedule call will never return, and
2704 * the scheduled task must drop that reference.
2705 * The test for TASK_DEAD must occur while the runqueue locks are
2706 * still held, otherwise prev could be scheduled on another cpu, die
2707 * there before we look at prev->state, and then the reference would
2709 * Manfred Spraul <manfred@colorfullife.com>
2711 prev_state
= prev
->state
;
2712 finish_arch_switch(prev
);
2713 finish_lock_switch(rq
, prev
);
2716 current
->sched_class
->post_schedule(rq
);
2719 fire_sched_in_preempt_notifiers(current
);
2722 if (unlikely(prev_state
== TASK_DEAD
)) {
2724 * Remove function-return probe instances associated with this
2725 * task and put them back on the free list.
2727 kprobe_flush_task(prev
);
2728 put_task_struct(prev
);
2733 * schedule_tail - first thing a freshly forked thread must call.
2734 * @prev: the thread we just switched away from.
2736 asmlinkage
void schedule_tail(struct task_struct
*prev
)
2737 __releases(rq
->lock
)
2739 struct rq
*rq
= this_rq();
2741 finish_task_switch(rq
, prev
);
2742 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2743 /* In this case, finish_task_switch does not reenable preemption */
2746 if (current
->set_child_tid
)
2747 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2751 * context_switch - switch to the new MM and the new
2752 * thread's register state.
2755 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2756 struct task_struct
*next
)
2758 struct mm_struct
*mm
, *oldmm
;
2760 prepare_task_switch(rq
, prev
, next
);
2761 trace_sched_switch(rq
, prev
, next
);
2763 oldmm
= prev
->active_mm
;
2765 * For paravirt, this is coupled with an exit in switch_to to
2766 * combine the page table reload and the switch backend into
2769 arch_enter_lazy_cpu_mode();
2771 if (unlikely(!mm
)) {
2772 next
->active_mm
= oldmm
;
2773 atomic_inc(&oldmm
->mm_count
);
2774 enter_lazy_tlb(oldmm
, next
);
2776 switch_mm(oldmm
, mm
, next
);
2778 if (unlikely(!prev
->mm
)) {
2779 prev
->active_mm
= NULL
;
2780 rq
->prev_mm
= oldmm
;
2783 * Since the runqueue lock will be released by the next
2784 * task (which is an invalid locking op but in the case
2785 * of the scheduler it's an obvious special-case), so we
2786 * do an early lockdep release here:
2788 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2789 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2792 /* Here we just switch the register state and the stack. */
2793 switch_to(prev
, next
, prev
);
2797 * this_rq must be evaluated again because prev may have moved
2798 * CPUs since it called schedule(), thus the 'rq' on its stack
2799 * frame will be invalid.
2801 finish_task_switch(this_rq(), prev
);
2805 * nr_running, nr_uninterruptible and nr_context_switches:
2807 * externally visible scheduler statistics: current number of runnable
2808 * threads, current number of uninterruptible-sleeping threads, total
2809 * number of context switches performed since bootup.
2811 unsigned long nr_running(void)
2813 unsigned long i
, sum
= 0;
2815 for_each_online_cpu(i
)
2816 sum
+= cpu_rq(i
)->nr_running
;
2821 unsigned long nr_uninterruptible(void)
2823 unsigned long i
, sum
= 0;
2825 for_each_possible_cpu(i
)
2826 sum
+= cpu_rq(i
)->nr_uninterruptible
;
2829 * Since we read the counters lockless, it might be slightly
2830 * inaccurate. Do not allow it to go below zero though:
2832 if (unlikely((long)sum
< 0))
2838 unsigned long long nr_context_switches(void)
2841 unsigned long long sum
= 0;
2843 for_each_possible_cpu(i
)
2844 sum
+= cpu_rq(i
)->nr_switches
;
2849 unsigned long nr_iowait(void)
2851 unsigned long i
, sum
= 0;
2853 for_each_possible_cpu(i
)
2854 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2859 unsigned long nr_active(void)
2861 unsigned long i
, running
= 0, uninterruptible
= 0;
2863 for_each_online_cpu(i
) {
2864 running
+= cpu_rq(i
)->nr_running
;
2865 uninterruptible
+= cpu_rq(i
)->nr_uninterruptible
;
2868 if (unlikely((long)uninterruptible
< 0))
2869 uninterruptible
= 0;
2871 return running
+ uninterruptible
;
2875 * Update rq->cpu_load[] statistics. This function is usually called every
2876 * scheduler tick (TICK_NSEC).
2878 static void update_cpu_load(struct rq
*this_rq
)
2880 unsigned long this_load
= this_rq
->load
.weight
;
2883 this_rq
->nr_load_updates
++;
2885 /* Update our load: */
2886 for (i
= 0, scale
= 1; i
< CPU_LOAD_IDX_MAX
; i
++, scale
+= scale
) {
2887 unsigned long old_load
, new_load
;
2889 /* scale is effectively 1 << i now, and >> i divides by scale */
2891 old_load
= this_rq
->cpu_load
[i
];
2892 new_load
= this_load
;
2894 * Round up the averaging division if load is increasing. This
2895 * prevents us from getting stuck on 9 if the load is 10, for
2898 if (new_load
> old_load
)
2899 new_load
+= scale
-1;
2900 this_rq
->cpu_load
[i
] = (old_load
*(scale
-1) + new_load
) >> i
;
2907 * double_rq_lock - safely lock two runqueues
2909 * Note this does not disable interrupts like task_rq_lock,
2910 * you need to do so manually before calling.
2912 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
)
2913 __acquires(rq1
->lock
)
2914 __acquires(rq2
->lock
)
2916 BUG_ON(!irqs_disabled());
2918 spin_lock(&rq1
->lock
);
2919 __acquire(rq2
->lock
); /* Fake it out ;) */
2922 spin_lock(&rq1
->lock
);
2923 spin_lock_nested(&rq2
->lock
, SINGLE_DEPTH_NESTING
);
2925 spin_lock(&rq2
->lock
);
2926 spin_lock_nested(&rq1
->lock
, SINGLE_DEPTH_NESTING
);
2929 update_rq_clock(rq1
);
2930 update_rq_clock(rq2
);
2934 * double_rq_unlock - safely unlock two runqueues
2936 * Note this does not restore interrupts like task_rq_unlock,
2937 * you need to do so manually after calling.
2939 static void double_rq_unlock(struct rq
*rq1
, struct rq
*rq2
)
2940 __releases(rq1
->lock
)
2941 __releases(rq2
->lock
)
2943 spin_unlock(&rq1
->lock
);
2945 spin_unlock(&rq2
->lock
);
2947 __release(rq2
->lock
);
2951 * If dest_cpu is allowed for this process, migrate the task to it.
2952 * This is accomplished by forcing the cpu_allowed mask to only
2953 * allow dest_cpu, which will force the cpu onto dest_cpu. Then
2954 * the cpu_allowed mask is restored.
2956 static void sched_migrate_task(struct task_struct
*p
, int dest_cpu
)
2958 struct migration_req req
;
2959 unsigned long flags
;
2962 rq
= task_rq_lock(p
, &flags
);
2963 if (!cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
)
2964 || unlikely(!cpu_active(dest_cpu
)))
2967 /* force the process onto the specified CPU */
2968 if (migrate_task(p
, dest_cpu
, &req
)) {
2969 /* Need to wait for migration thread (might exit: take ref). */
2970 struct task_struct
*mt
= rq
->migration_thread
;
2972 get_task_struct(mt
);
2973 task_rq_unlock(rq
, &flags
);
2974 wake_up_process(mt
);
2975 put_task_struct(mt
);
2976 wait_for_completion(&req
.done
);
2981 task_rq_unlock(rq
, &flags
);
2985 * sched_exec - execve() is a valuable balancing opportunity, because at
2986 * this point the task has the smallest effective memory and cache footprint.
2988 void sched_exec(void)
2990 int new_cpu
, this_cpu
= get_cpu();
2991 new_cpu
= sched_balance_self(this_cpu
, SD_BALANCE_EXEC
);
2993 if (new_cpu
!= this_cpu
)
2994 sched_migrate_task(current
, new_cpu
);
2998 * pull_task - move a task from a remote runqueue to the local runqueue.
2999 * Both runqueues must be locked.
3001 static void pull_task(struct rq
*src_rq
, struct task_struct
*p
,
3002 struct rq
*this_rq
, int this_cpu
)
3004 deactivate_task(src_rq
, p
, 0);
3005 set_task_cpu(p
, this_cpu
);
3006 activate_task(this_rq
, p
, 0);
3008 * Note that idle threads have a prio of MAX_PRIO, for this test
3009 * to be always true for them.
3011 check_preempt_curr(this_rq
, p
, 0);
3015 * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
3018 int can_migrate_task(struct task_struct
*p
, struct rq
*rq
, int this_cpu
,
3019 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3022 int tsk_cache_hot
= 0;
3024 * We do not migrate tasks that are:
3025 * 1) running (obviously), or
3026 * 2) cannot be migrated to this CPU due to cpus_allowed, or
3027 * 3) are cache-hot on their current CPU.
3029 if (!cpumask_test_cpu(this_cpu
, &p
->cpus_allowed
)) {
3030 schedstat_inc(p
, se
.nr_failed_migrations_affine
);
3035 if (task_running(rq
, p
)) {
3036 schedstat_inc(p
, se
.nr_failed_migrations_running
);
3041 * Aggressive migration if:
3042 * 1) task is cache cold, or
3043 * 2) too many balance attempts have failed.
3046 tsk_cache_hot
= task_hot(p
, rq
->clock
, sd
);
3047 if (!tsk_cache_hot
||
3048 sd
->nr_balance_failed
> sd
->cache_nice_tries
) {
3049 #ifdef CONFIG_SCHEDSTATS
3050 if (tsk_cache_hot
) {
3051 schedstat_inc(sd
, lb_hot_gained
[idle
]);
3052 schedstat_inc(p
, se
.nr_forced_migrations
);
3058 if (tsk_cache_hot
) {
3059 schedstat_inc(p
, se
.nr_failed_migrations_hot
);
3065 static unsigned long
3066 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3067 unsigned long max_load_move
, struct sched_domain
*sd
,
3068 enum cpu_idle_type idle
, int *all_pinned
,
3069 int *this_best_prio
, struct rq_iterator
*iterator
)
3071 int loops
= 0, pulled
= 0, pinned
= 0;
3072 struct task_struct
*p
;
3073 long rem_load_move
= max_load_move
;
3075 if (max_load_move
== 0)
3081 * Start the load-balancing iterator:
3083 p
= iterator
->start(iterator
->arg
);
3085 if (!p
|| loops
++ > sysctl_sched_nr_migrate
)
3088 if ((p
->se
.load
.weight
>> 1) > rem_load_move
||
3089 !can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
3090 p
= iterator
->next(iterator
->arg
);
3094 pull_task(busiest
, p
, this_rq
, this_cpu
);
3096 rem_load_move
-= p
->se
.load
.weight
;
3098 #ifdef CONFIG_PREEMPT
3100 * NEWIDLE balancing is a source of latency, so preemptible kernels
3101 * will stop after the first task is pulled to minimize the critical
3104 if (idle
== CPU_NEWLY_IDLE
)
3109 * We only want to steal up to the prescribed amount of weighted load.
3111 if (rem_load_move
> 0) {
3112 if (p
->prio
< *this_best_prio
)
3113 *this_best_prio
= p
->prio
;
3114 p
= iterator
->next(iterator
->arg
);
3119 * Right now, this is one of only two places pull_task() is called,
3120 * so we can safely collect pull_task() stats here rather than
3121 * inside pull_task().
3123 schedstat_add(sd
, lb_gained
[idle
], pulled
);
3126 *all_pinned
= pinned
;
3128 return max_load_move
- rem_load_move
;
3132 * move_tasks tries to move up to max_load_move weighted load from busiest to
3133 * this_rq, as part of a balancing operation within domain "sd".
3134 * Returns 1 if successful and 0 otherwise.
3136 * Called with both runqueues locked.
3138 static int move_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3139 unsigned long max_load_move
,
3140 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3143 const struct sched_class
*class = sched_class_highest
;
3144 unsigned long total_load_moved
= 0;
3145 int this_best_prio
= this_rq
->curr
->prio
;
3149 class->load_balance(this_rq
, this_cpu
, busiest
,
3150 max_load_move
- total_load_moved
,
3151 sd
, idle
, all_pinned
, &this_best_prio
);
3152 class = class->next
;
3154 #ifdef CONFIG_PREEMPT
3156 * NEWIDLE balancing is a source of latency, so preemptible
3157 * kernels will stop after the first task is pulled to minimize
3158 * the critical section.
3160 if (idle
== CPU_NEWLY_IDLE
&& this_rq
->nr_running
)
3163 } while (class && max_load_move
> total_load_moved
);
3165 return total_load_moved
> 0;
3169 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3170 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3171 struct rq_iterator
*iterator
)
3173 struct task_struct
*p
= iterator
->start(iterator
->arg
);
3177 if (can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
3178 pull_task(busiest
, p
, this_rq
, this_cpu
);
3180 * Right now, this is only the second place pull_task()
3181 * is called, so we can safely collect pull_task()
3182 * stats here rather than inside pull_task().
3184 schedstat_inc(sd
, lb_gained
[idle
]);
3188 p
= iterator
->next(iterator
->arg
);
3195 * move_one_task tries to move exactly one task from busiest to this_rq, as
3196 * part of active balancing operations within "domain".
3197 * Returns 1 if successful and 0 otherwise.
3199 * Called with both runqueues locked.
3201 static int move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3202 struct sched_domain
*sd
, enum cpu_idle_type idle
)
3204 const struct sched_class
*class;
3206 for (class = sched_class_highest
; class; class = class->next
)
3207 if (class->move_one_task(this_rq
, this_cpu
, busiest
, sd
, idle
))
3212 /********** Helpers for find_busiest_group ************************/
3214 * sd_lb_stats - Structure to store the statistics of a sched_domain
3215 * during load balancing.
3217 struct sd_lb_stats
{
3218 struct sched_group
*busiest
; /* Busiest group in this sd */
3219 struct sched_group
*this; /* Local group in this sd */
3220 unsigned long total_load
; /* Total load of all groups in sd */
3221 unsigned long total_pwr
; /* Total power of all groups in sd */
3222 unsigned long avg_load
; /* Average load across all groups in sd */
3224 /** Statistics of this group */
3225 unsigned long this_load
;
3226 unsigned long this_load_per_task
;
3227 unsigned long this_nr_running
;
3229 /* Statistics of the busiest group */
3230 unsigned long max_load
;
3231 unsigned long busiest_load_per_task
;
3232 unsigned long busiest_nr_running
;
3234 int group_imb
; /* Is there imbalance in this sd */
3235 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3236 int power_savings_balance
; /* Is powersave balance needed for this sd */
3237 struct sched_group
*group_min
; /* Least loaded group in sd */
3238 struct sched_group
*group_leader
; /* Group which relieves group_min */
3239 unsigned long min_load_per_task
; /* load_per_task in group_min */
3240 unsigned long leader_nr_running
; /* Nr running of group_leader */
3241 unsigned long min_nr_running
; /* Nr running of group_min */
3246 * sg_lb_stats - stats of a sched_group required for load_balancing
3248 struct sg_lb_stats
{
3249 unsigned long avg_load
; /*Avg load across the CPUs of the group */
3250 unsigned long group_load
; /* Total load over the CPUs of the group */
3251 unsigned long sum_nr_running
; /* Nr tasks running in the group */
3252 unsigned long sum_weighted_load
; /* Weighted load of group's tasks */
3253 unsigned long group_capacity
;
3254 int group_imb
; /* Is there an imbalance in the group ? */
3258 * group_first_cpu - Returns the first cpu in the cpumask of a sched_group.
3259 * @group: The group whose first cpu is to be returned.
3261 static inline unsigned int group_first_cpu(struct sched_group
*group
)
3263 return cpumask_first(sched_group_cpus(group
));
3267 * get_sd_load_idx - Obtain the load index for a given sched domain.
3268 * @sd: The sched_domain whose load_idx is to be obtained.
3269 * @idle: The Idle status of the CPU for whose sd load_icx is obtained.
3271 static inline int get_sd_load_idx(struct sched_domain
*sd
,
3272 enum cpu_idle_type idle
)
3278 load_idx
= sd
->busy_idx
;
3281 case CPU_NEWLY_IDLE
:
3282 load_idx
= sd
->newidle_idx
;
3285 load_idx
= sd
->idle_idx
;
3293 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3295 * init_sd_power_savings_stats - Initialize power savings statistics for
3296 * the given sched_domain, during load balancing.
3298 * @sd: Sched domain whose power-savings statistics are to be initialized.
3299 * @sds: Variable containing the statistics for sd.
3300 * @idle: Idle status of the CPU at which we're performing load-balancing.
3302 static inline void init_sd_power_savings_stats(struct sched_domain
*sd
,
3303 struct sd_lb_stats
*sds
, enum cpu_idle_type idle
)
3306 * Busy processors will not participate in power savings
3309 if (idle
== CPU_NOT_IDLE
|| !(sd
->flags
& SD_POWERSAVINGS_BALANCE
))
3310 sds
->power_savings_balance
= 0;
3312 sds
->power_savings_balance
= 1;
3313 sds
->min_nr_running
= ULONG_MAX
;
3314 sds
->leader_nr_running
= 0;
3319 * update_sd_power_savings_stats - Update the power saving stats for a
3320 * sched_domain while performing load balancing.
3322 * @group: sched_group belonging to the sched_domain under consideration.
3323 * @sds: Variable containing the statistics of the sched_domain
3324 * @local_group: Does group contain the CPU for which we're performing
3326 * @sgs: Variable containing the statistics of the group.
3328 static inline void update_sd_power_savings_stats(struct sched_group
*group
,
3329 struct sd_lb_stats
*sds
, int local_group
, struct sg_lb_stats
*sgs
)
3332 if (!sds
->power_savings_balance
)
3336 * If the local group is idle or completely loaded
3337 * no need to do power savings balance at this domain
3339 if (local_group
&& (sds
->this_nr_running
>= sgs
->group_capacity
||
3340 !sds
->this_nr_running
))
3341 sds
->power_savings_balance
= 0;
3344 * If a group is already running at full capacity or idle,
3345 * don't include that group in power savings calculations
3347 if (!sds
->power_savings_balance
||
3348 sgs
->sum_nr_running
>= sgs
->group_capacity
||
3349 !sgs
->sum_nr_running
)
3353 * Calculate the group which has the least non-idle load.
3354 * This is the group from where we need to pick up the load
3357 if ((sgs
->sum_nr_running
< sds
->min_nr_running
) ||
3358 (sgs
->sum_nr_running
== sds
->min_nr_running
&&
3359 group_first_cpu(group
) > group_first_cpu(sds
->group_min
))) {
3360 sds
->group_min
= group
;
3361 sds
->min_nr_running
= sgs
->sum_nr_running
;
3362 sds
->min_load_per_task
= sgs
->sum_weighted_load
/
3363 sgs
->sum_nr_running
;
3367 * Calculate the group which is almost near its
3368 * capacity but still has some space to pick up some load
3369 * from other group and save more power
3371 if (sgs
->sum_nr_running
> sgs
->group_capacity
- 1)
3374 if (sgs
->sum_nr_running
> sds
->leader_nr_running
||
3375 (sgs
->sum_nr_running
== sds
->leader_nr_running
&&
3376 group_first_cpu(group
) < group_first_cpu(sds
->group_leader
))) {
3377 sds
->group_leader
= group
;
3378 sds
->leader_nr_running
= sgs
->sum_nr_running
;
3383 * check_power_save_busiest_group - see if there is potential for some power-savings balance
3384 * @sds: Variable containing the statistics of the sched_domain
3385 * under consideration.
3386 * @this_cpu: Cpu at which we're currently performing load-balancing.
3387 * @imbalance: Variable to store the imbalance.
3390 * Check if we have potential to perform some power-savings balance.
3391 * If yes, set the busiest group to be the least loaded group in the
3392 * sched_domain, so that it's CPUs can be put to idle.
3394 * Returns 1 if there is potential to perform power-savings balance.
3397 static inline int check_power_save_busiest_group(struct sd_lb_stats
*sds
,
3398 int this_cpu
, unsigned long *imbalance
)
3400 if (!sds
->power_savings_balance
)
3403 if (sds
->this != sds
->group_leader
||
3404 sds
->group_leader
== sds
->group_min
)
3407 *imbalance
= sds
->min_load_per_task
;
3408 sds
->busiest
= sds
->group_min
;
3410 if (sched_mc_power_savings
>= POWERSAVINGS_BALANCE_WAKEUP
) {
3411 cpu_rq(this_cpu
)->rd
->sched_mc_preferred_wakeup_cpu
=
3412 group_first_cpu(sds
->group_leader
);
3418 #else /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
3419 static inline void init_sd_power_savings_stats(struct sched_domain
*sd
,
3420 struct sd_lb_stats
*sds
, enum cpu_idle_type idle
)
3425 static inline void update_sd_power_savings_stats(struct sched_group
*group
,
3426 struct sd_lb_stats
*sds
, int local_group
, struct sg_lb_stats
*sgs
)
3431 static inline int check_power_save_busiest_group(struct sd_lb_stats
*sds
,
3432 int this_cpu
, unsigned long *imbalance
)
3436 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
3440 * update_sg_lb_stats - Update sched_group's statistics for load balancing.
3441 * @group: sched_group whose statistics are to be updated.
3442 * @this_cpu: Cpu for which load balance is currently performed.
3443 * @idle: Idle status of this_cpu
3444 * @load_idx: Load index of sched_domain of this_cpu for load calc.
3445 * @sd_idle: Idle status of the sched_domain containing group.
3446 * @local_group: Does group contain this_cpu.
3447 * @cpus: Set of cpus considered for load balancing.
3448 * @balance: Should we balance.
3449 * @sgs: variable to hold the statistics for this group.
3451 static inline void update_sg_lb_stats(struct sched_group
*group
, int this_cpu
,
3452 enum cpu_idle_type idle
, int load_idx
, int *sd_idle
,
3453 int local_group
, const struct cpumask
*cpus
,
3454 int *balance
, struct sg_lb_stats
*sgs
)
3456 unsigned long load
, max_cpu_load
, min_cpu_load
;
3458 unsigned int balance_cpu
= -1, first_idle_cpu
= 0;
3459 unsigned long sum_avg_load_per_task
;
3460 unsigned long avg_load_per_task
;
3463 balance_cpu
= group_first_cpu(group
);
3465 /* Tally up the load of all CPUs in the group */
3466 sum_avg_load_per_task
= avg_load_per_task
= 0;
3468 min_cpu_load
= ~0UL;
3470 for_each_cpu_and(i
, sched_group_cpus(group
), cpus
) {
3471 struct rq
*rq
= cpu_rq(i
);
3473 if (*sd_idle
&& rq
->nr_running
)
3476 /* Bias balancing toward cpus of our domain */
3478 if (idle_cpu(i
) && !first_idle_cpu
) {
3483 load
= target_load(i
, load_idx
);
3485 load
= source_load(i
, load_idx
);
3486 if (load
> max_cpu_load
)
3487 max_cpu_load
= load
;
3488 if (min_cpu_load
> load
)
3489 min_cpu_load
= load
;
3492 sgs
->group_load
+= load
;
3493 sgs
->sum_nr_running
+= rq
->nr_running
;
3494 sgs
->sum_weighted_load
+= weighted_cpuload(i
);
3496 sum_avg_load_per_task
+= cpu_avg_load_per_task(i
);
3500 * First idle cpu or the first cpu(busiest) in this sched group
3501 * is eligible for doing load balancing at this and above
3502 * domains. In the newly idle case, we will allow all the cpu's
3503 * to do the newly idle load balance.
3505 if (idle
!= CPU_NEWLY_IDLE
&& local_group
&&
3506 balance_cpu
!= this_cpu
&& balance
) {
3511 /* Adjust by relative CPU power of the group */
3512 sgs
->avg_load
= sg_div_cpu_power(group
,
3513 sgs
->group_load
* SCHED_LOAD_SCALE
);
3517 * Consider the group unbalanced when the imbalance is larger
3518 * than the average weight of two tasks.
3520 * APZ: with cgroup the avg task weight can vary wildly and
3521 * might not be a suitable number - should we keep a
3522 * normalized nr_running number somewhere that negates
3525 avg_load_per_task
= sg_div_cpu_power(group
,
3526 sum_avg_load_per_task
* SCHED_LOAD_SCALE
);
3528 if ((max_cpu_load
- min_cpu_load
) > 2*avg_load_per_task
)
3531 sgs
->group_capacity
= group
->__cpu_power
/ SCHED_LOAD_SCALE
;
3536 * update_sd_lb_stats - Update sched_group's statistics for load balancing.
3537 * @sd: sched_domain whose statistics are to be updated.
3538 * @this_cpu: Cpu for which load balance is currently performed.
3539 * @idle: Idle status of this_cpu
3540 * @sd_idle: Idle status of the sched_domain containing group.
3541 * @cpus: Set of cpus considered for load balancing.
3542 * @balance: Should we balance.
3543 * @sds: variable to hold the statistics for this sched_domain.
3545 static inline void update_sd_lb_stats(struct sched_domain
*sd
, int this_cpu
,
3546 enum cpu_idle_type idle
, int *sd_idle
,
3547 const struct cpumask
*cpus
, int *balance
,
3548 struct sd_lb_stats
*sds
)
3550 struct sched_group
*group
= sd
->groups
;
3551 struct sg_lb_stats sgs
;
3554 init_sd_power_savings_stats(sd
, sds
, idle
);
3555 load_idx
= get_sd_load_idx(sd
, idle
);
3560 local_group
= cpumask_test_cpu(this_cpu
,
3561 sched_group_cpus(group
));
3562 memset(&sgs
, 0, sizeof(sgs
));
3563 update_sg_lb_stats(group
, this_cpu
, idle
, load_idx
, sd_idle
,
3564 local_group
, cpus
, balance
, &sgs
);
3566 if (local_group
&& balance
&& !(*balance
))
3569 sds
->total_load
+= sgs
.group_load
;
3570 sds
->total_pwr
+= group
->__cpu_power
;
3573 sds
->this_load
= sgs
.avg_load
;
3575 sds
->this_nr_running
= sgs
.sum_nr_running
;
3576 sds
->this_load_per_task
= sgs
.sum_weighted_load
;
3577 } else if (sgs
.avg_load
> sds
->max_load
&&
3578 (sgs
.sum_nr_running
> sgs
.group_capacity
||
3580 sds
->max_load
= sgs
.avg_load
;
3581 sds
->busiest
= group
;
3582 sds
->busiest_nr_running
= sgs
.sum_nr_running
;
3583 sds
->busiest_load_per_task
= sgs
.sum_weighted_load
;
3584 sds
->group_imb
= sgs
.group_imb
;
3587 update_sd_power_savings_stats(group
, sds
, local_group
, &sgs
);
3588 group
= group
->next
;
3589 } while (group
!= sd
->groups
);
3594 * fix_small_imbalance - Calculate the minor imbalance that exists
3595 * amongst the groups of a sched_domain, during
3597 * @sds: Statistics of the sched_domain whose imbalance is to be calculated.
3598 * @this_cpu: The cpu at whose sched_domain we're performing load-balance.
3599 * @imbalance: Variable to store the imbalance.
3601 static inline void fix_small_imbalance(struct sd_lb_stats
*sds
,
3602 int this_cpu
, unsigned long *imbalance
)
3604 unsigned long tmp
, pwr_now
= 0, pwr_move
= 0;
3605 unsigned int imbn
= 2;
3607 if (sds
->this_nr_running
) {
3608 sds
->this_load_per_task
/= sds
->this_nr_running
;
3609 if (sds
->busiest_load_per_task
>
3610 sds
->this_load_per_task
)
3613 sds
->this_load_per_task
=
3614 cpu_avg_load_per_task(this_cpu
);
3616 if (sds
->max_load
- sds
->this_load
+ sds
->busiest_load_per_task
>=
3617 sds
->busiest_load_per_task
* imbn
) {
3618 *imbalance
= sds
->busiest_load_per_task
;
3623 * OK, we don't have enough imbalance to justify moving tasks,
3624 * however we may be able to increase total CPU power used by
3628 pwr_now
+= sds
->busiest
->__cpu_power
*
3629 min(sds
->busiest_load_per_task
, sds
->max_load
);
3630 pwr_now
+= sds
->this->__cpu_power
*
3631 min(sds
->this_load_per_task
, sds
->this_load
);
3632 pwr_now
/= SCHED_LOAD_SCALE
;
3634 /* Amount of load we'd subtract */
3635 tmp
= sg_div_cpu_power(sds
->busiest
,
3636 sds
->busiest_load_per_task
* SCHED_LOAD_SCALE
);
3637 if (sds
->max_load
> tmp
)
3638 pwr_move
+= sds
->busiest
->__cpu_power
*
3639 min(sds
->busiest_load_per_task
, sds
->max_load
- tmp
);
3641 /* Amount of load we'd add */
3642 if (sds
->max_load
* sds
->busiest
->__cpu_power
<
3643 sds
->busiest_load_per_task
* SCHED_LOAD_SCALE
)
3644 tmp
= sg_div_cpu_power(sds
->this,
3645 sds
->max_load
* sds
->busiest
->__cpu_power
);
3647 tmp
= sg_div_cpu_power(sds
->this,
3648 sds
->busiest_load_per_task
* SCHED_LOAD_SCALE
);
3649 pwr_move
+= sds
->this->__cpu_power
*
3650 min(sds
->this_load_per_task
, sds
->this_load
+ tmp
);
3651 pwr_move
/= SCHED_LOAD_SCALE
;
3653 /* Move if we gain throughput */
3654 if (pwr_move
> pwr_now
)
3655 *imbalance
= sds
->busiest_load_per_task
;
3659 * calculate_imbalance - Calculate the amount of imbalance present within the
3660 * groups of a given sched_domain during load balance.
3661 * @sds: statistics of the sched_domain whose imbalance is to be calculated.
3662 * @this_cpu: Cpu for which currently load balance is being performed.
3663 * @imbalance: The variable to store the imbalance.
3665 static inline void calculate_imbalance(struct sd_lb_stats
*sds
, int this_cpu
,
3666 unsigned long *imbalance
)
3668 unsigned long max_pull
;
3670 * In the presence of smp nice balancing, certain scenarios can have
3671 * max load less than avg load(as we skip the groups at or below
3672 * its cpu_power, while calculating max_load..)
3674 if (sds
->max_load
< sds
->avg_load
) {
3676 return fix_small_imbalance(sds
, this_cpu
, imbalance
);
3679 /* Don't want to pull so many tasks that a group would go idle */
3680 max_pull
= min(sds
->max_load
- sds
->avg_load
,
3681 sds
->max_load
- sds
->busiest_load_per_task
);
3683 /* How much load to actually move to equalise the imbalance */
3684 *imbalance
= min(max_pull
* sds
->busiest
->__cpu_power
,
3685 (sds
->avg_load
- sds
->this_load
) * sds
->this->__cpu_power
)
3689 * if *imbalance is less than the average load per runnable task
3690 * there is no gaurantee that any tasks will be moved so we'll have
3691 * a think about bumping its value to force at least one task to be
3694 if (*imbalance
< sds
->busiest_load_per_task
)
3695 return fix_small_imbalance(sds
, this_cpu
, imbalance
);
3698 /******* find_busiest_group() helpers end here *********************/
3701 * find_busiest_group - Returns the busiest group within the sched_domain
3702 * if there is an imbalance. If there isn't an imbalance, and
3703 * the user has opted for power-savings, it returns a group whose
3704 * CPUs can be put to idle by rebalancing those tasks elsewhere, if
3705 * such a group exists.
3707 * Also calculates the amount of weighted load which should be moved
3708 * to restore balance.
3710 * @sd: The sched_domain whose busiest group is to be returned.
3711 * @this_cpu: The cpu for which load balancing is currently being performed.
3712 * @imbalance: Variable which stores amount of weighted load which should
3713 * be moved to restore balance/put a group to idle.
3714 * @idle: The idle status of this_cpu.
3715 * @sd_idle: The idleness of sd
3716 * @cpus: The set of CPUs under consideration for load-balancing.
3717 * @balance: Pointer to a variable indicating if this_cpu
3718 * is the appropriate cpu to perform load balancing at this_level.
3720 * Returns: - the busiest group if imbalance exists.
3721 * - If no imbalance and user has opted for power-savings balance,
3722 * return the least loaded group whose CPUs can be
3723 * put to idle by rebalancing its tasks onto our group.
3725 static struct sched_group
*
3726 find_busiest_group(struct sched_domain
*sd
, int this_cpu
,
3727 unsigned long *imbalance
, enum cpu_idle_type idle
,
3728 int *sd_idle
, const struct cpumask
*cpus
, int *balance
)
3730 struct sd_lb_stats sds
;
3732 memset(&sds
, 0, sizeof(sds
));
3735 * Compute the various statistics relavent for load balancing at
3738 update_sd_lb_stats(sd
, this_cpu
, idle
, sd_idle
, cpus
,
3741 /* Cases where imbalance does not exist from POV of this_cpu */
3742 /* 1) this_cpu is not the appropriate cpu to perform load balancing
3744 * 2) There is no busy sibling group to pull from.
3745 * 3) This group is the busiest group.
3746 * 4) This group is more busy than the avg busieness at this
3748 * 5) The imbalance is within the specified limit.
3749 * 6) Any rebalance would lead to ping-pong
3751 if (balance
&& !(*balance
))
3754 if (!sds
.busiest
|| sds
.busiest_nr_running
== 0)
3757 if (sds
.this_load
>= sds
.max_load
)
3760 sds
.avg_load
= (SCHED_LOAD_SCALE
* sds
.total_load
) / sds
.total_pwr
;
3762 if (sds
.this_load
>= sds
.avg_load
)
3765 if (100 * sds
.max_load
<= sd
->imbalance_pct
* sds
.this_load
)
3768 sds
.busiest_load_per_task
/= sds
.busiest_nr_running
;
3770 sds
.busiest_load_per_task
=
3771 min(sds
.busiest_load_per_task
, sds
.avg_load
);
3774 * We're trying to get all the cpus to the average_load, so we don't
3775 * want to push ourselves above the average load, nor do we wish to
3776 * reduce the max loaded cpu below the average load, as either of these
3777 * actions would just result in more rebalancing later, and ping-pong
3778 * tasks around. Thus we look for the minimum possible imbalance.
3779 * Negative imbalances (*we* are more loaded than anyone else) will
3780 * be counted as no imbalance for these purposes -- we can't fix that
3781 * by pulling tasks to us. Be careful of negative numbers as they'll
3782 * appear as very large values with unsigned longs.
3784 if (sds
.max_load
<= sds
.busiest_load_per_task
)
3787 /* Looks like there is an imbalance. Compute it */
3788 calculate_imbalance(&sds
, this_cpu
, imbalance
);
3793 * There is no obvious imbalance. But check if we can do some balancing
3796 if (check_power_save_busiest_group(&sds
, this_cpu
, imbalance
))
3804 * find_busiest_queue - find the busiest runqueue among the cpus in group.
3807 find_busiest_queue(struct sched_group
*group
, enum cpu_idle_type idle
,
3808 unsigned long imbalance
, const struct cpumask
*cpus
)
3810 struct rq
*busiest
= NULL
, *rq
;
3811 unsigned long max_load
= 0;
3814 for_each_cpu(i
, sched_group_cpus(group
)) {
3817 if (!cpumask_test_cpu(i
, cpus
))
3821 wl
= weighted_cpuload(i
);
3823 if (rq
->nr_running
== 1 && wl
> imbalance
)
3826 if (wl
> max_load
) {
3836 * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
3837 * so long as it is large enough.
3839 #define MAX_PINNED_INTERVAL 512
3841 /* Working cpumask for load_balance and load_balance_newidle. */
3842 static DEFINE_PER_CPU(cpumask_var_t
, load_balance_tmpmask
);
3845 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3846 * tasks if there is an imbalance.
3848 static int load_balance(int this_cpu
, struct rq
*this_rq
,
3849 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3852 int ld_moved
, all_pinned
= 0, active_balance
= 0, sd_idle
= 0;
3853 struct sched_group
*group
;
3854 unsigned long imbalance
;
3856 unsigned long flags
;
3857 struct cpumask
*cpus
= __get_cpu_var(load_balance_tmpmask
);
3859 cpumask_setall(cpus
);
3862 * When power savings policy is enabled for the parent domain, idle
3863 * sibling can pick up load irrespective of busy siblings. In this case,
3864 * let the state of idle sibling percolate up as CPU_IDLE, instead of
3865 * portraying it as CPU_NOT_IDLE.
3867 if (idle
!= CPU_NOT_IDLE
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3868 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3871 schedstat_inc(sd
, lb_count
[idle
]);
3875 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, idle
, &sd_idle
,
3882 schedstat_inc(sd
, lb_nobusyg
[idle
]);
3886 busiest
= find_busiest_queue(group
, idle
, imbalance
, cpus
);
3888 schedstat_inc(sd
, lb_nobusyq
[idle
]);
3892 BUG_ON(busiest
== this_rq
);
3894 schedstat_add(sd
, lb_imbalance
[idle
], imbalance
);
3897 if (busiest
->nr_running
> 1) {
3899 * Attempt to move tasks. If find_busiest_group has found
3900 * an imbalance but busiest->nr_running <= 1, the group is
3901 * still unbalanced. ld_moved simply stays zero, so it is
3902 * correctly treated as an imbalance.
3904 local_irq_save(flags
);
3905 double_rq_lock(this_rq
, busiest
);
3906 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
3907 imbalance
, sd
, idle
, &all_pinned
);
3908 double_rq_unlock(this_rq
, busiest
);
3909 local_irq_restore(flags
);
3912 * some other cpu did the load balance for us.
3914 if (ld_moved
&& this_cpu
!= smp_processor_id())
3915 resched_cpu(this_cpu
);
3917 /* All tasks on this runqueue were pinned by CPU affinity */
3918 if (unlikely(all_pinned
)) {
3919 cpumask_clear_cpu(cpu_of(busiest
), cpus
);
3920 if (!cpumask_empty(cpus
))
3927 schedstat_inc(sd
, lb_failed
[idle
]);
3928 sd
->nr_balance_failed
++;
3930 if (unlikely(sd
->nr_balance_failed
> sd
->cache_nice_tries
+2)) {
3932 spin_lock_irqsave(&busiest
->lock
, flags
);
3934 /* don't kick the migration_thread, if the curr
3935 * task on busiest cpu can't be moved to this_cpu
3937 if (!cpumask_test_cpu(this_cpu
,
3938 &busiest
->curr
->cpus_allowed
)) {
3939 spin_unlock_irqrestore(&busiest
->lock
, flags
);
3941 goto out_one_pinned
;
3944 if (!busiest
->active_balance
) {
3945 busiest
->active_balance
= 1;
3946 busiest
->push_cpu
= this_cpu
;
3949 spin_unlock_irqrestore(&busiest
->lock
, flags
);
3951 wake_up_process(busiest
->migration_thread
);
3954 * We've kicked active balancing, reset the failure
3957 sd
->nr_balance_failed
= sd
->cache_nice_tries
+1;
3960 sd
->nr_balance_failed
= 0;
3962 if (likely(!active_balance
)) {
3963 /* We were unbalanced, so reset the balancing interval */
3964 sd
->balance_interval
= sd
->min_interval
;
3967 * If we've begun active balancing, start to back off. This
3968 * case may not be covered by the all_pinned logic if there
3969 * is only 1 task on the busy runqueue (because we don't call
3972 if (sd
->balance_interval
< sd
->max_interval
)
3973 sd
->balance_interval
*= 2;
3976 if (!ld_moved
&& !sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3977 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3983 schedstat_inc(sd
, lb_balanced
[idle
]);
3985 sd
->nr_balance_failed
= 0;
3988 /* tune up the balancing interval */
3989 if ((all_pinned
&& sd
->balance_interval
< MAX_PINNED_INTERVAL
) ||
3990 (sd
->balance_interval
< sd
->max_interval
))
3991 sd
->balance_interval
*= 2;
3993 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3994 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4005 * Check this_cpu to ensure it is balanced within domain. Attempt to move
4006 * tasks if there is an imbalance.
4008 * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE).
4009 * this_rq is locked.
4012 load_balance_newidle(int this_cpu
, struct rq
*this_rq
, struct sched_domain
*sd
)
4014 struct sched_group
*group
;
4015 struct rq
*busiest
= NULL
;
4016 unsigned long imbalance
;
4020 struct cpumask
*cpus
= __get_cpu_var(load_balance_tmpmask
);
4022 cpumask_setall(cpus
);
4025 * When power savings policy is enabled for the parent domain, idle
4026 * sibling can pick up load irrespective of busy siblings. In this case,
4027 * let the state of idle sibling percolate up as IDLE, instead of
4028 * portraying it as CPU_NOT_IDLE.
4030 if (sd
->flags
& SD_SHARE_CPUPOWER
&&
4031 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4034 schedstat_inc(sd
, lb_count
[CPU_NEWLY_IDLE
]);
4036 update_shares_locked(this_rq
, sd
);
4037 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, CPU_NEWLY_IDLE
,
4038 &sd_idle
, cpus
, NULL
);
4040 schedstat_inc(sd
, lb_nobusyg
[CPU_NEWLY_IDLE
]);
4044 busiest
= find_busiest_queue(group
, CPU_NEWLY_IDLE
, imbalance
, cpus
);
4046 schedstat_inc(sd
, lb_nobusyq
[CPU_NEWLY_IDLE
]);
4050 BUG_ON(busiest
== this_rq
);
4052 schedstat_add(sd
, lb_imbalance
[CPU_NEWLY_IDLE
], imbalance
);
4055 if (busiest
->nr_running
> 1) {
4056 /* Attempt to move tasks */
4057 double_lock_balance(this_rq
, busiest
);
4058 /* this_rq->clock is already updated */
4059 update_rq_clock(busiest
);
4060 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
4061 imbalance
, sd
, CPU_NEWLY_IDLE
,
4063 double_unlock_balance(this_rq
, busiest
);
4065 if (unlikely(all_pinned
)) {
4066 cpumask_clear_cpu(cpu_of(busiest
), cpus
);
4067 if (!cpumask_empty(cpus
))
4073 int active_balance
= 0;
4075 schedstat_inc(sd
, lb_failed
[CPU_NEWLY_IDLE
]);
4076 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
4077 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4080 if (sched_mc_power_savings
< POWERSAVINGS_BALANCE_WAKEUP
)
4083 if (sd
->nr_balance_failed
++ < 2)
4087 * The only task running in a non-idle cpu can be moved to this
4088 * cpu in an attempt to completely freeup the other CPU
4089 * package. The same method used to move task in load_balance()
4090 * have been extended for load_balance_newidle() to speedup
4091 * consolidation at sched_mc=POWERSAVINGS_BALANCE_WAKEUP (2)
4093 * The package power saving logic comes from
4094 * find_busiest_group(). If there are no imbalance, then
4095 * f_b_g() will return NULL. However when sched_mc={1,2} then
4096 * f_b_g() will select a group from which a running task may be
4097 * pulled to this cpu in order to make the other package idle.
4098 * If there is no opportunity to make a package idle and if
4099 * there are no imbalance, then f_b_g() will return NULL and no
4100 * action will be taken in load_balance_newidle().
4102 * Under normal task pull operation due to imbalance, there
4103 * will be more than one task in the source run queue and
4104 * move_tasks() will succeed. ld_moved will be true and this
4105 * active balance code will not be triggered.
4108 /* Lock busiest in correct order while this_rq is held */
4109 double_lock_balance(this_rq
, busiest
);
4112 * don't kick the migration_thread, if the curr
4113 * task on busiest cpu can't be moved to this_cpu
4115 if (!cpumask_test_cpu(this_cpu
, &busiest
->curr
->cpus_allowed
)) {
4116 double_unlock_balance(this_rq
, busiest
);
4121 if (!busiest
->active_balance
) {
4122 busiest
->active_balance
= 1;
4123 busiest
->push_cpu
= this_cpu
;
4127 double_unlock_balance(this_rq
, busiest
);
4129 * Should not call ttwu while holding a rq->lock
4131 spin_unlock(&this_rq
->lock
);
4133 wake_up_process(busiest
->migration_thread
);
4134 spin_lock(&this_rq
->lock
);
4137 sd
->nr_balance_failed
= 0;
4139 update_shares_locked(this_rq
, sd
);
4143 schedstat_inc(sd
, lb_balanced
[CPU_NEWLY_IDLE
]);
4144 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
4145 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4147 sd
->nr_balance_failed
= 0;
4153 * idle_balance is called by schedule() if this_cpu is about to become
4154 * idle. Attempts to pull tasks from other CPUs.
4156 static void idle_balance(int this_cpu
, struct rq
*this_rq
)
4158 struct sched_domain
*sd
;
4159 int pulled_task
= 0;
4160 unsigned long next_balance
= jiffies
+ HZ
;
4162 for_each_domain(this_cpu
, sd
) {
4163 unsigned long interval
;
4165 if (!(sd
->flags
& SD_LOAD_BALANCE
))
4168 if (sd
->flags
& SD_BALANCE_NEWIDLE
)
4169 /* If we've pulled tasks over stop searching: */
4170 pulled_task
= load_balance_newidle(this_cpu
, this_rq
,
4173 interval
= msecs_to_jiffies(sd
->balance_interval
);
4174 if (time_after(next_balance
, sd
->last_balance
+ interval
))
4175 next_balance
= sd
->last_balance
+ interval
;
4179 if (pulled_task
|| time_after(jiffies
, this_rq
->next_balance
)) {
4181 * We are going idle. next_balance may be set based on
4182 * a busy processor. So reset next_balance.
4184 this_rq
->next_balance
= next_balance
;
4189 * active_load_balance is run by migration threads. It pushes running tasks
4190 * off the busiest CPU onto idle CPUs. It requires at least 1 task to be
4191 * running on each physical CPU where possible, and avoids physical /
4192 * logical imbalances.
4194 * Called with busiest_rq locked.
4196 static void active_load_balance(struct rq
*busiest_rq
, int busiest_cpu
)
4198 int target_cpu
= busiest_rq
->push_cpu
;
4199 struct sched_domain
*sd
;
4200 struct rq
*target_rq
;
4202 /* Is there any task to move? */
4203 if (busiest_rq
->nr_running
<= 1)
4206 target_rq
= cpu_rq(target_cpu
);
4209 * This condition is "impossible", if it occurs
4210 * we need to fix it. Originally reported by
4211 * Bjorn Helgaas on a 128-cpu setup.
4213 BUG_ON(busiest_rq
== target_rq
);
4215 /* move a task from busiest_rq to target_rq */
4216 double_lock_balance(busiest_rq
, target_rq
);
4217 update_rq_clock(busiest_rq
);
4218 update_rq_clock(target_rq
);
4220 /* Search for an sd spanning us and the target CPU. */
4221 for_each_domain(target_cpu
, sd
) {
4222 if ((sd
->flags
& SD_LOAD_BALANCE
) &&
4223 cpumask_test_cpu(busiest_cpu
, sched_domain_span(sd
)))
4228 schedstat_inc(sd
, alb_count
);
4230 if (move_one_task(target_rq
, target_cpu
, busiest_rq
,
4232 schedstat_inc(sd
, alb_pushed
);
4234 schedstat_inc(sd
, alb_failed
);
4236 double_unlock_balance(busiest_rq
, target_rq
);
4241 atomic_t load_balancer
;
4242 cpumask_var_t cpu_mask
;
4243 cpumask_var_t ilb_grp_nohz_mask
;
4244 } nohz ____cacheline_aligned
= {
4245 .load_balancer
= ATOMIC_INIT(-1),
4248 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
4250 * lowest_flag_domain - Return lowest sched_domain containing flag.
4251 * @cpu: The cpu whose lowest level of sched domain is to
4253 * @flag: The flag to check for the lowest sched_domain
4254 * for the given cpu.
4256 * Returns the lowest sched_domain of a cpu which contains the given flag.
4258 static inline struct sched_domain
*lowest_flag_domain(int cpu
, int flag
)
4260 struct sched_domain
*sd
;
4262 for_each_domain(cpu
, sd
)
4263 if (sd
&& (sd
->flags
& flag
))
4270 * for_each_flag_domain - Iterates over sched_domains containing the flag.
4271 * @cpu: The cpu whose domains we're iterating over.
4272 * @sd: variable holding the value of the power_savings_sd
4274 * @flag: The flag to filter the sched_domains to be iterated.
4276 * Iterates over all the scheduler domains for a given cpu that has the 'flag'
4277 * set, starting from the lowest sched_domain to the highest.
4279 #define for_each_flag_domain(cpu, sd, flag) \
4280 for (sd = lowest_flag_domain(cpu, flag); \
4281 (sd && (sd->flags & flag)); sd = sd->parent)
4284 * is_semi_idle_group - Checks if the given sched_group is semi-idle.
4285 * @ilb_group: group to be checked for semi-idleness
4287 * Returns: 1 if the group is semi-idle. 0 otherwise.
4289 * We define a sched_group to be semi idle if it has atleast one idle-CPU
4290 * and atleast one non-idle CPU. This helper function checks if the given
4291 * sched_group is semi-idle or not.
4293 static inline int is_semi_idle_group(struct sched_group
*ilb_group
)
4295 cpumask_and(nohz
.ilb_grp_nohz_mask
, nohz
.cpu_mask
,
4296 sched_group_cpus(ilb_group
));
4299 * A sched_group is semi-idle when it has atleast one busy cpu
4300 * and atleast one idle cpu.
4302 if (cpumask_empty(nohz
.ilb_grp_nohz_mask
))
4305 if (cpumask_equal(nohz
.ilb_grp_nohz_mask
, sched_group_cpus(ilb_group
)))
4311 * find_new_ilb - Finds the optimum idle load balancer for nomination.
4312 * @cpu: The cpu which is nominating a new idle_load_balancer.
4314 * Returns: Returns the id of the idle load balancer if it exists,
4315 * Else, returns >= nr_cpu_ids.
4317 * This algorithm picks the idle load balancer such that it belongs to a
4318 * semi-idle powersavings sched_domain. The idea is to try and avoid
4319 * completely idle packages/cores just for the purpose of idle load balancing
4320 * when there are other idle cpu's which are better suited for that job.
4322 static int find_new_ilb(int cpu
)
4324 struct sched_domain
*sd
;
4325 struct sched_group
*ilb_group
;
4328 * Have idle load balancer selection from semi-idle packages only
4329 * when power-aware load balancing is enabled
4331 if (!(sched_smt_power_savings
|| sched_mc_power_savings
))
4335 * Optimize for the case when we have no idle CPUs or only one
4336 * idle CPU. Don't walk the sched_domain hierarchy in such cases
4338 if (cpumask_weight(nohz
.cpu_mask
) < 2)
4341 for_each_flag_domain(cpu
, sd
, SD_POWERSAVINGS_BALANCE
) {
4342 ilb_group
= sd
->groups
;
4345 if (is_semi_idle_group(ilb_group
))
4346 return cpumask_first(nohz
.ilb_grp_nohz_mask
);
4348 ilb_group
= ilb_group
->next
;
4350 } while (ilb_group
!= sd
->groups
);
4354 return cpumask_first(nohz
.cpu_mask
);
4356 #else /* (CONFIG_SCHED_MC || CONFIG_SCHED_SMT) */
4357 static inline int find_new_ilb(int call_cpu
)
4359 return cpumask_first(nohz
.cpu_mask
);
4364 * This routine will try to nominate the ilb (idle load balancing)
4365 * owner among the cpus whose ticks are stopped. ilb owner will do the idle
4366 * load balancing on behalf of all those cpus. If all the cpus in the system
4367 * go into this tickless mode, then there will be no ilb owner (as there is
4368 * no need for one) and all the cpus will sleep till the next wakeup event
4371 * For the ilb owner, tick is not stopped. And this tick will be used
4372 * for idle load balancing. ilb owner will still be part of
4375 * While stopping the tick, this cpu will become the ilb owner if there
4376 * is no other owner. And will be the owner till that cpu becomes busy
4377 * or if all cpus in the system stop their ticks at which point
4378 * there is no need for ilb owner.
4380 * When the ilb owner becomes busy, it nominates another owner, during the
4381 * next busy scheduler_tick()
4383 int select_nohz_load_balancer(int stop_tick
)
4385 int cpu
= smp_processor_id();
4388 cpu_rq(cpu
)->in_nohz_recently
= 1;
4390 if (!cpu_active(cpu
)) {
4391 if (atomic_read(&nohz
.load_balancer
) != cpu
)
4395 * If we are going offline and still the leader,
4398 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
4404 cpumask_set_cpu(cpu
, nohz
.cpu_mask
);
4406 /* time for ilb owner also to sleep */
4407 if (cpumask_weight(nohz
.cpu_mask
) == num_online_cpus()) {
4408 if (atomic_read(&nohz
.load_balancer
) == cpu
)
4409 atomic_set(&nohz
.load_balancer
, -1);
4413 if (atomic_read(&nohz
.load_balancer
) == -1) {
4414 /* make me the ilb owner */
4415 if (atomic_cmpxchg(&nohz
.load_balancer
, -1, cpu
) == -1)
4417 } else if (atomic_read(&nohz
.load_balancer
) == cpu
) {
4420 if (!(sched_smt_power_savings
||
4421 sched_mc_power_savings
))
4424 * Check to see if there is a more power-efficient
4427 new_ilb
= find_new_ilb(cpu
);
4428 if (new_ilb
< nr_cpu_ids
&& new_ilb
!= cpu
) {
4429 atomic_set(&nohz
.load_balancer
, -1);
4430 resched_cpu(new_ilb
);
4436 if (!cpumask_test_cpu(cpu
, nohz
.cpu_mask
))
4439 cpumask_clear_cpu(cpu
, nohz
.cpu_mask
);
4441 if (atomic_read(&nohz
.load_balancer
) == cpu
)
4442 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
4449 static DEFINE_SPINLOCK(balancing
);
4452 * It checks each scheduling domain to see if it is due to be balanced,
4453 * and initiates a balancing operation if so.
4455 * Balancing parameters are set up in arch_init_sched_domains.
4457 static void rebalance_domains(int cpu
, enum cpu_idle_type idle
)
4460 struct rq
*rq
= cpu_rq(cpu
);
4461 unsigned long interval
;
4462 struct sched_domain
*sd
;
4463 /* Earliest time when we have to do rebalance again */
4464 unsigned long next_balance
= jiffies
+ 60*HZ
;
4465 int update_next_balance
= 0;
4468 for_each_domain(cpu
, sd
) {
4469 if (!(sd
->flags
& SD_LOAD_BALANCE
))
4472 interval
= sd
->balance_interval
;
4473 if (idle
!= CPU_IDLE
)
4474 interval
*= sd
->busy_factor
;
4476 /* scale ms to jiffies */
4477 interval
= msecs_to_jiffies(interval
);
4478 if (unlikely(!interval
))
4480 if (interval
> HZ
*NR_CPUS
/10)
4481 interval
= HZ
*NR_CPUS
/10;
4483 need_serialize
= sd
->flags
& SD_SERIALIZE
;
4485 if (need_serialize
) {
4486 if (!spin_trylock(&balancing
))
4490 if (time_after_eq(jiffies
, sd
->last_balance
+ interval
)) {
4491 if (load_balance(cpu
, rq
, sd
, idle
, &balance
)) {
4493 * We've pulled tasks over so either we're no
4494 * longer idle, or one of our SMT siblings is
4497 idle
= CPU_NOT_IDLE
;
4499 sd
->last_balance
= jiffies
;
4502 spin_unlock(&balancing
);
4504 if (time_after(next_balance
, sd
->last_balance
+ interval
)) {
4505 next_balance
= sd
->last_balance
+ interval
;
4506 update_next_balance
= 1;
4510 * Stop the load balance at this level. There is another
4511 * CPU in our sched group which is doing load balancing more
4519 * next_balance will be updated only when there is a need.
4520 * When the cpu is attached to null domain for ex, it will not be
4523 if (likely(update_next_balance
))
4524 rq
->next_balance
= next_balance
;
4528 * run_rebalance_domains is triggered when needed from the scheduler tick.
4529 * In CONFIG_NO_HZ case, the idle load balance owner will do the
4530 * rebalancing for all the cpus for whom scheduler ticks are stopped.
4532 static void run_rebalance_domains(struct softirq_action
*h
)
4534 int this_cpu
= smp_processor_id();
4535 struct rq
*this_rq
= cpu_rq(this_cpu
);
4536 enum cpu_idle_type idle
= this_rq
->idle_at_tick
?
4537 CPU_IDLE
: CPU_NOT_IDLE
;
4539 rebalance_domains(this_cpu
, idle
);
4543 * If this cpu is the owner for idle load balancing, then do the
4544 * balancing on behalf of the other idle cpus whose ticks are
4547 if (this_rq
->idle_at_tick
&&
4548 atomic_read(&nohz
.load_balancer
) == this_cpu
) {
4552 for_each_cpu(balance_cpu
, nohz
.cpu_mask
) {
4553 if (balance_cpu
== this_cpu
)
4557 * If this cpu gets work to do, stop the load balancing
4558 * work being done for other cpus. Next load
4559 * balancing owner will pick it up.
4564 rebalance_domains(balance_cpu
, CPU_IDLE
);
4566 rq
= cpu_rq(balance_cpu
);
4567 if (time_after(this_rq
->next_balance
, rq
->next_balance
))
4568 this_rq
->next_balance
= rq
->next_balance
;
4574 static inline int on_null_domain(int cpu
)
4576 return !rcu_dereference(cpu_rq(cpu
)->sd
);
4580 * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
4582 * In case of CONFIG_NO_HZ, this is the place where we nominate a new
4583 * idle load balancing owner or decide to stop the periodic load balancing,
4584 * if the whole system is idle.
4586 static inline void trigger_load_balance(struct rq
*rq
, int cpu
)
4590 * If we were in the nohz mode recently and busy at the current
4591 * scheduler tick, then check if we need to nominate new idle
4594 if (rq
->in_nohz_recently
&& !rq
->idle_at_tick
) {
4595 rq
->in_nohz_recently
= 0;
4597 if (atomic_read(&nohz
.load_balancer
) == cpu
) {
4598 cpumask_clear_cpu(cpu
, nohz
.cpu_mask
);
4599 atomic_set(&nohz
.load_balancer
, -1);
4602 if (atomic_read(&nohz
.load_balancer
) == -1) {
4603 int ilb
= find_new_ilb(cpu
);
4605 if (ilb
< nr_cpu_ids
)
4611 * If this cpu is idle and doing idle load balancing for all the
4612 * cpus with ticks stopped, is it time for that to stop?
4614 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) == cpu
&&
4615 cpumask_weight(nohz
.cpu_mask
) == num_online_cpus()) {
4621 * If this cpu is idle and the idle load balancing is done by
4622 * someone else, then no need raise the SCHED_SOFTIRQ
4624 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) != cpu
&&
4625 cpumask_test_cpu(cpu
, nohz
.cpu_mask
))
4628 /* Don't need to rebalance while attached to NULL domain */
4629 if (time_after_eq(jiffies
, rq
->next_balance
) &&
4630 likely(!on_null_domain(cpu
)))
4631 raise_softirq(SCHED_SOFTIRQ
);
4634 #else /* CONFIG_SMP */
4637 * on UP we do not need to balance between CPUs:
4639 static inline void idle_balance(int cpu
, struct rq
*rq
)
4645 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
4647 EXPORT_PER_CPU_SYMBOL(kstat
);
4650 * Return any ns on the sched_clock that have not yet been accounted in
4651 * @p in case that task is currently running.
4653 * Called with task_rq_lock() held on @rq.
4655 static u64
do_task_delta_exec(struct task_struct
*p
, struct rq
*rq
)
4659 if (task_current(rq
, p
)) {
4660 update_rq_clock(rq
);
4661 ns
= rq
->clock
- p
->se
.exec_start
;
4669 unsigned long long task_delta_exec(struct task_struct
*p
)
4671 unsigned long flags
;
4675 rq
= task_rq_lock(p
, &flags
);
4676 ns
= do_task_delta_exec(p
, rq
);
4677 task_rq_unlock(rq
, &flags
);
4683 * Return accounted runtime for the task.
4684 * In case the task is currently running, return the runtime plus current's
4685 * pending runtime that have not been accounted yet.
4687 unsigned long long task_sched_runtime(struct task_struct
*p
)
4689 unsigned long flags
;
4693 rq
= task_rq_lock(p
, &flags
);
4694 ns
= p
->se
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
4695 task_rq_unlock(rq
, &flags
);
4701 * Return sum_exec_runtime for the thread group.
4702 * In case the task is currently running, return the sum plus current's
4703 * pending runtime that have not been accounted yet.
4705 * Note that the thread group might have other running tasks as well,
4706 * so the return value not includes other pending runtime that other
4707 * running tasks might have.
4709 unsigned long long thread_group_sched_runtime(struct task_struct
*p
)
4711 struct task_cputime totals
;
4712 unsigned long flags
;
4716 rq
= task_rq_lock(p
, &flags
);
4717 thread_group_cputime(p
, &totals
);
4718 ns
= totals
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
4719 task_rq_unlock(rq
, &flags
);
4725 * Account user cpu time to a process.
4726 * @p: the process that the cpu time gets accounted to
4727 * @cputime: the cpu time spent in user space since the last update
4728 * @cputime_scaled: cputime scaled by cpu frequency
4730 void account_user_time(struct task_struct
*p
, cputime_t cputime
,
4731 cputime_t cputime_scaled
)
4733 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
4736 /* Add user time to process. */
4737 p
->utime
= cputime_add(p
->utime
, cputime
);
4738 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
4739 account_group_user_time(p
, cputime
);
4741 /* Add user time to cpustat. */
4742 tmp
= cputime_to_cputime64(cputime
);
4743 if (TASK_NICE(p
) > 0)
4744 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
4746 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
4748 cpuacct_update_stats(p
, CPUACCT_STAT_USER
, cputime
);
4749 /* Account for user time used */
4750 acct_update_integrals(p
);
4754 * Account guest cpu time to a process.
4755 * @p: the process that the cpu time gets accounted to
4756 * @cputime: the cpu time spent in virtual machine since the last update
4757 * @cputime_scaled: cputime scaled by cpu frequency
4759 static void account_guest_time(struct task_struct
*p
, cputime_t cputime
,
4760 cputime_t cputime_scaled
)
4763 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
4765 tmp
= cputime_to_cputime64(cputime
);
4767 /* Add guest time to process. */
4768 p
->utime
= cputime_add(p
->utime
, cputime
);
4769 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
4770 account_group_user_time(p
, cputime
);
4771 p
->gtime
= cputime_add(p
->gtime
, cputime
);
4773 /* Add guest time to cpustat. */
4774 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
4775 cpustat
->guest
= cputime64_add(cpustat
->guest
, tmp
);
4779 * Account system cpu time to a process.
4780 * @p: the process that the cpu time gets accounted to
4781 * @hardirq_offset: the offset to subtract from hardirq_count()
4782 * @cputime: the cpu time spent in kernel space since the last update
4783 * @cputime_scaled: cputime scaled by cpu frequency
4785 void account_system_time(struct task_struct
*p
, int hardirq_offset
,
4786 cputime_t cputime
, cputime_t cputime_scaled
)
4788 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
4791 if ((p
->flags
& PF_VCPU
) && (irq_count() - hardirq_offset
== 0)) {
4792 account_guest_time(p
, cputime
, cputime_scaled
);
4796 /* Add system time to process. */
4797 p
->stime
= cputime_add(p
->stime
, cputime
);
4798 p
->stimescaled
= cputime_add(p
->stimescaled
, cputime_scaled
);
4799 account_group_system_time(p
, cputime
);
4801 /* Add system time to cpustat. */
4802 tmp
= cputime_to_cputime64(cputime
);
4803 if (hardirq_count() - hardirq_offset
)
4804 cpustat
->irq
= cputime64_add(cpustat
->irq
, tmp
);
4805 else if (softirq_count())
4806 cpustat
->softirq
= cputime64_add(cpustat
->softirq
, tmp
);
4808 cpustat
->system
= cputime64_add(cpustat
->system
, tmp
);
4810 cpuacct_update_stats(p
, CPUACCT_STAT_SYSTEM
, cputime
);
4812 /* Account for system time used */
4813 acct_update_integrals(p
);
4817 * Account for involuntary wait time.
4818 * @steal: the cpu time spent in involuntary wait
4820 void account_steal_time(cputime_t cputime
)
4822 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
4823 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
4825 cpustat
->steal
= cputime64_add(cpustat
->steal
, cputime64
);
4829 * Account for idle time.
4830 * @cputime: the cpu time spent in idle wait
4832 void account_idle_time(cputime_t cputime
)
4834 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
4835 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
4836 struct rq
*rq
= this_rq();
4838 if (atomic_read(&rq
->nr_iowait
) > 0)
4839 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, cputime64
);
4841 cpustat
->idle
= cputime64_add(cpustat
->idle
, cputime64
);
4844 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
4847 * Account a single tick of cpu time.
4848 * @p: the process that the cpu time gets accounted to
4849 * @user_tick: indicates if the tick is a user or a system tick
4851 void account_process_tick(struct task_struct
*p
, int user_tick
)
4853 cputime_t one_jiffy
= jiffies_to_cputime(1);
4854 cputime_t one_jiffy_scaled
= cputime_to_scaled(one_jiffy
);
4855 struct rq
*rq
= this_rq();
4858 account_user_time(p
, one_jiffy
, one_jiffy_scaled
);
4859 else if ((p
!= rq
->idle
) || (irq_count() != HARDIRQ_OFFSET
))
4860 account_system_time(p
, HARDIRQ_OFFSET
, one_jiffy
,
4863 account_idle_time(one_jiffy
);
4867 * Account multiple ticks of steal time.
4868 * @p: the process from which the cpu time has been stolen
4869 * @ticks: number of stolen ticks
4871 void account_steal_ticks(unsigned long ticks
)
4873 account_steal_time(jiffies_to_cputime(ticks
));
4877 * Account multiple ticks of idle time.
4878 * @ticks: number of stolen ticks
4880 void account_idle_ticks(unsigned long ticks
)
4882 account_idle_time(jiffies_to_cputime(ticks
));
4888 * Use precise platform statistics if available:
4890 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
4891 cputime_t
task_utime(struct task_struct
*p
)
4896 cputime_t
task_stime(struct task_struct
*p
)
4901 cputime_t
task_utime(struct task_struct
*p
)
4903 clock_t utime
= cputime_to_clock_t(p
->utime
),
4904 total
= utime
+ cputime_to_clock_t(p
->stime
);
4908 * Use CFS's precise accounting:
4910 temp
= (u64
)nsec_to_clock_t(p
->se
.sum_exec_runtime
);
4914 do_div(temp
, total
);
4916 utime
= (clock_t)temp
;
4918 p
->prev_utime
= max(p
->prev_utime
, clock_t_to_cputime(utime
));
4919 return p
->prev_utime
;
4922 cputime_t
task_stime(struct task_struct
*p
)
4927 * Use CFS's precise accounting. (we subtract utime from
4928 * the total, to make sure the total observed by userspace
4929 * grows monotonically - apps rely on that):
4931 stime
= nsec_to_clock_t(p
->se
.sum_exec_runtime
) -
4932 cputime_to_clock_t(task_utime(p
));
4935 p
->prev_stime
= max(p
->prev_stime
, clock_t_to_cputime(stime
));
4937 return p
->prev_stime
;
4941 inline cputime_t
task_gtime(struct task_struct
*p
)
4947 * This function gets called by the timer code, with HZ frequency.
4948 * We call it with interrupts disabled.
4950 * It also gets called by the fork code, when changing the parent's
4953 void scheduler_tick(void)
4955 int cpu
= smp_processor_id();
4956 struct rq
*rq
= cpu_rq(cpu
);
4957 struct task_struct
*curr
= rq
->curr
;
4961 spin_lock(&rq
->lock
);
4962 update_rq_clock(rq
);
4963 update_cpu_load(rq
);
4964 curr
->sched_class
->task_tick(rq
, curr
, 0);
4965 spin_unlock(&rq
->lock
);
4968 rq
->idle_at_tick
= idle_cpu(cpu
);
4969 trigger_load_balance(rq
, cpu
);
4973 notrace
unsigned long get_parent_ip(unsigned long addr
)
4975 if (in_lock_functions(addr
)) {
4976 addr
= CALLER_ADDR2
;
4977 if (in_lock_functions(addr
))
4978 addr
= CALLER_ADDR3
;
4983 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
4984 defined(CONFIG_PREEMPT_TRACER))
4986 void __kprobes
add_preempt_count(int val
)
4988 #ifdef CONFIG_DEBUG_PREEMPT
4992 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
4995 preempt_count() += val
;
4996 #ifdef CONFIG_DEBUG_PREEMPT
4998 * Spinlock count overflowing soon?
5000 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
5003 if (preempt_count() == val
)
5004 trace_preempt_off(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
5006 EXPORT_SYMBOL(add_preempt_count
);
5008 void __kprobes
sub_preempt_count(int val
)
5010 #ifdef CONFIG_DEBUG_PREEMPT
5014 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
5017 * Is the spinlock portion underflowing?
5019 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
5020 !(preempt_count() & PREEMPT_MASK
)))
5024 if (preempt_count() == val
)
5025 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
5026 preempt_count() -= val
;
5028 EXPORT_SYMBOL(sub_preempt_count
);
5033 * Print scheduling while atomic bug:
5035 static noinline
void __schedule_bug(struct task_struct
*prev
)
5037 struct pt_regs
*regs
= get_irq_regs();
5039 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
5040 prev
->comm
, prev
->pid
, preempt_count());
5042 debug_show_held_locks(prev
);
5044 if (irqs_disabled())
5045 print_irqtrace_events(prev
);
5054 * Various schedule()-time debugging checks and statistics:
5056 static inline void schedule_debug(struct task_struct
*prev
)
5059 * Test if we are atomic. Since do_exit() needs to call into
5060 * schedule() atomically, we ignore that path for now.
5061 * Otherwise, whine if we are scheduling when we should not be.
5063 if (unlikely(in_atomic_preempt_off() && !prev
->exit_state
))
5064 __schedule_bug(prev
);
5066 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
5068 schedstat_inc(this_rq(), sched_count
);
5069 #ifdef CONFIG_SCHEDSTATS
5070 if (unlikely(prev
->lock_depth
>= 0)) {
5071 schedstat_inc(this_rq(), bkl_count
);
5072 schedstat_inc(prev
, sched_info
.bkl_count
);
5077 static void put_prev_task(struct rq
*rq
, struct task_struct
*prev
)
5079 if (prev
->state
== TASK_RUNNING
) {
5080 u64 runtime
= prev
->se
.sum_exec_runtime
;
5082 runtime
-= prev
->se
.prev_sum_exec_runtime
;
5083 runtime
= min_t(u64
, runtime
, 2*sysctl_sched_migration_cost
);
5086 * In order to avoid avg_overlap growing stale when we are
5087 * indeed overlapping and hence not getting put to sleep, grow
5088 * the avg_overlap on preemption.
5090 * We use the average preemption runtime because that
5091 * correlates to the amount of cache footprint a task can
5094 update_avg(&prev
->se
.avg_overlap
, runtime
);
5096 prev
->sched_class
->put_prev_task(rq
, prev
);
5100 * Pick up the highest-prio task:
5102 static inline struct task_struct
*
5103 pick_next_task(struct rq
*rq
)
5105 const struct sched_class
*class;
5106 struct task_struct
*p
;
5109 * Optimization: we know that if all tasks are in
5110 * the fair class we can call that function directly:
5112 if (likely(rq
->nr_running
== rq
->cfs
.nr_running
)) {
5113 p
= fair_sched_class
.pick_next_task(rq
);
5118 class = sched_class_highest
;
5120 p
= class->pick_next_task(rq
);
5124 * Will never be NULL as the idle class always
5125 * returns a non-NULL p:
5127 class = class->next
;
5132 * schedule() is the main scheduler function.
5134 asmlinkage
void __sched
schedule(void)
5136 struct task_struct
*prev
, *next
;
5137 unsigned long *switch_count
;
5143 cpu
= smp_processor_id();
5147 switch_count
= &prev
->nivcsw
;
5149 release_kernel_lock(prev
);
5150 need_resched_nonpreemptible
:
5152 schedule_debug(prev
);
5154 if (sched_feat(HRTICK
))
5157 spin_lock_irq(&rq
->lock
);
5158 update_rq_clock(rq
);
5159 clear_tsk_need_resched(prev
);
5161 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
5162 if (unlikely(signal_pending_state(prev
->state
, prev
)))
5163 prev
->state
= TASK_RUNNING
;
5165 deactivate_task(rq
, prev
, 1);
5166 switch_count
= &prev
->nvcsw
;
5170 if (prev
->sched_class
->pre_schedule
)
5171 prev
->sched_class
->pre_schedule(rq
, prev
);
5174 if (unlikely(!rq
->nr_running
))
5175 idle_balance(cpu
, rq
);
5177 put_prev_task(rq
, prev
);
5178 next
= pick_next_task(rq
);
5180 if (likely(prev
!= next
)) {
5181 sched_info_switch(prev
, next
);
5187 context_switch(rq
, prev
, next
); /* unlocks the rq */
5189 * the context switch might have flipped the stack from under
5190 * us, hence refresh the local variables.
5192 cpu
= smp_processor_id();
5195 spin_unlock_irq(&rq
->lock
);
5197 if (unlikely(reacquire_kernel_lock(current
) < 0))
5198 goto need_resched_nonpreemptible
;
5200 preempt_enable_no_resched();
5204 EXPORT_SYMBOL(schedule
);
5208 * Look out! "owner" is an entirely speculative pointer
5209 * access and not reliable.
5211 int mutex_spin_on_owner(struct mutex
*lock
, struct thread_info
*owner
)
5216 if (!sched_feat(OWNER_SPIN
))
5219 #ifdef CONFIG_DEBUG_PAGEALLOC
5221 * Need to access the cpu field knowing that
5222 * DEBUG_PAGEALLOC could have unmapped it if
5223 * the mutex owner just released it and exited.
5225 if (probe_kernel_address(&owner
->cpu
, cpu
))
5232 * Even if the access succeeded (likely case),
5233 * the cpu field may no longer be valid.
5235 if (cpu
>= nr_cpumask_bits
)
5239 * We need to validate that we can do a
5240 * get_cpu() and that we have the percpu area.
5242 if (!cpu_online(cpu
))
5249 * Owner changed, break to re-assess state.
5251 if (lock
->owner
!= owner
)
5255 * Is that owner really running on that cpu?
5257 if (task_thread_info(rq
->curr
) != owner
|| need_resched())
5267 #ifdef CONFIG_PREEMPT
5269 * this is the entry point to schedule() from in-kernel preemption
5270 * off of preempt_enable. Kernel preemptions off return from interrupt
5271 * occur there and call schedule directly.
5273 asmlinkage
void __sched
preempt_schedule(void)
5275 struct thread_info
*ti
= current_thread_info();
5278 * If there is a non-zero preempt_count or interrupts are disabled,
5279 * we do not want to preempt the current task. Just return..
5281 if (likely(ti
->preempt_count
|| irqs_disabled()))
5285 add_preempt_count(PREEMPT_ACTIVE
);
5287 sub_preempt_count(PREEMPT_ACTIVE
);
5290 * Check again in case we missed a preemption opportunity
5291 * between schedule and now.
5294 } while (need_resched());
5296 EXPORT_SYMBOL(preempt_schedule
);
5299 * this is the entry point to schedule() from kernel preemption
5300 * off of irq context.
5301 * Note, that this is called and return with irqs disabled. This will
5302 * protect us against recursive calling from irq.
5304 asmlinkage
void __sched
preempt_schedule_irq(void)
5306 struct thread_info
*ti
= current_thread_info();
5308 /* Catch callers which need to be fixed */
5309 BUG_ON(ti
->preempt_count
|| !irqs_disabled());
5312 add_preempt_count(PREEMPT_ACTIVE
);
5315 local_irq_disable();
5316 sub_preempt_count(PREEMPT_ACTIVE
);
5319 * Check again in case we missed a preemption opportunity
5320 * between schedule and now.
5323 } while (need_resched());
5326 #endif /* CONFIG_PREEMPT */
5328 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int sync
,
5331 return try_to_wake_up(curr
->private, mode
, sync
);
5333 EXPORT_SYMBOL(default_wake_function
);
5336 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
5337 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
5338 * number) then we wake all the non-exclusive tasks and one exclusive task.
5340 * There are circumstances in which we can try to wake a task which has already
5341 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
5342 * zero in this (rare) case, and we handle it by continuing to scan the queue.
5344 static void __wake_up_common(wait_queue_head_t
*q
, unsigned int mode
,
5345 int nr_exclusive
, int sync
, void *key
)
5347 wait_queue_t
*curr
, *next
;
5349 list_for_each_entry_safe(curr
, next
, &q
->task_list
, task_list
) {
5350 unsigned flags
= curr
->flags
;
5352 if (curr
->func(curr
, mode
, sync
, key
) &&
5353 (flags
& WQ_FLAG_EXCLUSIVE
) && !--nr_exclusive
)
5359 * __wake_up - wake up threads blocked on a waitqueue.
5361 * @mode: which threads
5362 * @nr_exclusive: how many wake-one or wake-many threads to wake up
5363 * @key: is directly passed to the wakeup function
5365 void __wake_up(wait_queue_head_t
*q
, unsigned int mode
,
5366 int nr_exclusive
, void *key
)
5368 unsigned long flags
;
5370 spin_lock_irqsave(&q
->lock
, flags
);
5371 __wake_up_common(q
, mode
, nr_exclusive
, 0, key
);
5372 spin_unlock_irqrestore(&q
->lock
, flags
);
5374 EXPORT_SYMBOL(__wake_up
);
5377 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
5379 void __wake_up_locked(wait_queue_head_t
*q
, unsigned int mode
)
5381 __wake_up_common(q
, mode
, 1, 0, NULL
);
5384 void __wake_up_locked_key(wait_queue_head_t
*q
, unsigned int mode
, void *key
)
5386 __wake_up_common(q
, mode
, 1, 0, key
);
5390 * __wake_up_sync_key - wake up threads blocked on a waitqueue.
5392 * @mode: which threads
5393 * @nr_exclusive: how many wake-one or wake-many threads to wake up
5394 * @key: opaque value to be passed to wakeup targets
5396 * The sync wakeup differs that the waker knows that it will schedule
5397 * away soon, so while the target thread will be woken up, it will not
5398 * be migrated to another CPU - ie. the two threads are 'synchronized'
5399 * with each other. This can prevent needless bouncing between CPUs.
5401 * On UP it can prevent extra preemption.
5403 void __wake_up_sync_key(wait_queue_head_t
*q
, unsigned int mode
,
5404 int nr_exclusive
, void *key
)
5406 unsigned long flags
;
5412 if (unlikely(!nr_exclusive
))
5415 spin_lock_irqsave(&q
->lock
, flags
);
5416 __wake_up_common(q
, mode
, nr_exclusive
, sync
, key
);
5417 spin_unlock_irqrestore(&q
->lock
, flags
);
5419 EXPORT_SYMBOL_GPL(__wake_up_sync_key
);
5422 * __wake_up_sync - see __wake_up_sync_key()
5424 void __wake_up_sync(wait_queue_head_t
*q
, unsigned int mode
, int nr_exclusive
)
5426 __wake_up_sync_key(q
, mode
, nr_exclusive
, NULL
);
5428 EXPORT_SYMBOL_GPL(__wake_up_sync
); /* For internal use only */
5431 * complete: - signals a single thread waiting on this completion
5432 * @x: holds the state of this particular completion
5434 * This will wake up a single thread waiting on this completion. Threads will be
5435 * awakened in the same order in which they were queued.
5437 * See also complete_all(), wait_for_completion() and related routines.
5439 void complete(struct completion
*x
)
5441 unsigned long flags
;
5443 spin_lock_irqsave(&x
->wait
.lock
, flags
);
5445 __wake_up_common(&x
->wait
, TASK_NORMAL
, 1, 0, NULL
);
5446 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
5448 EXPORT_SYMBOL(complete
);
5451 * complete_all: - signals all threads waiting on this completion
5452 * @x: holds the state of this particular completion
5454 * This will wake up all threads waiting on this particular completion event.
5456 void complete_all(struct completion
*x
)
5458 unsigned long flags
;
5460 spin_lock_irqsave(&x
->wait
.lock
, flags
);
5461 x
->done
+= UINT_MAX
/2;
5462 __wake_up_common(&x
->wait
, TASK_NORMAL
, 0, 0, NULL
);
5463 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
5465 EXPORT_SYMBOL(complete_all
);
5467 static inline long __sched
5468 do_wait_for_common(struct completion
*x
, long timeout
, int state
)
5471 DECLARE_WAITQUEUE(wait
, current
);
5473 wait
.flags
|= WQ_FLAG_EXCLUSIVE
;
5474 __add_wait_queue_tail(&x
->wait
, &wait
);
5476 if (signal_pending_state(state
, current
)) {
5477 timeout
= -ERESTARTSYS
;
5480 __set_current_state(state
);
5481 spin_unlock_irq(&x
->wait
.lock
);
5482 timeout
= schedule_timeout(timeout
);
5483 spin_lock_irq(&x
->wait
.lock
);
5484 } while (!x
->done
&& timeout
);
5485 __remove_wait_queue(&x
->wait
, &wait
);
5490 return timeout
?: 1;
5494 wait_for_common(struct completion
*x
, long timeout
, int state
)
5498 spin_lock_irq(&x
->wait
.lock
);
5499 timeout
= do_wait_for_common(x
, timeout
, state
);
5500 spin_unlock_irq(&x
->wait
.lock
);
5505 * wait_for_completion: - waits for completion of a task
5506 * @x: holds the state of this particular completion
5508 * This waits to be signaled for completion of a specific task. It is NOT
5509 * interruptible and there is no timeout.
5511 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
5512 * and interrupt capability. Also see complete().
5514 void __sched
wait_for_completion(struct completion
*x
)
5516 wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
5518 EXPORT_SYMBOL(wait_for_completion
);
5521 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
5522 * @x: holds the state of this particular completion
5523 * @timeout: timeout value in jiffies
5525 * This waits for either a completion of a specific task to be signaled or for a
5526 * specified timeout to expire. The timeout is in jiffies. It is not
5529 unsigned long __sched
5530 wait_for_completion_timeout(struct completion
*x
, unsigned long timeout
)
5532 return wait_for_common(x
, timeout
, TASK_UNINTERRUPTIBLE
);
5534 EXPORT_SYMBOL(wait_for_completion_timeout
);
5537 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
5538 * @x: holds the state of this particular completion
5540 * This waits for completion of a specific task to be signaled. It is
5543 int __sched
wait_for_completion_interruptible(struct completion
*x
)
5545 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_INTERRUPTIBLE
);
5546 if (t
== -ERESTARTSYS
)
5550 EXPORT_SYMBOL(wait_for_completion_interruptible
);
5553 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
5554 * @x: holds the state of this particular completion
5555 * @timeout: timeout value in jiffies
5557 * This waits for either a completion of a specific task to be signaled or for a
5558 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
5560 unsigned long __sched
5561 wait_for_completion_interruptible_timeout(struct completion
*x
,
5562 unsigned long timeout
)
5564 return wait_for_common(x
, timeout
, TASK_INTERRUPTIBLE
);
5566 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout
);
5569 * wait_for_completion_killable: - waits for completion of a task (killable)
5570 * @x: holds the state of this particular completion
5572 * This waits to be signaled for completion of a specific task. It can be
5573 * interrupted by a kill signal.
5575 int __sched
wait_for_completion_killable(struct completion
*x
)
5577 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_KILLABLE
);
5578 if (t
== -ERESTARTSYS
)
5582 EXPORT_SYMBOL(wait_for_completion_killable
);
5585 * try_wait_for_completion - try to decrement a completion without blocking
5586 * @x: completion structure
5588 * Returns: 0 if a decrement cannot be done without blocking
5589 * 1 if a decrement succeeded.
5591 * If a completion is being used as a counting completion,
5592 * attempt to decrement the counter without blocking. This
5593 * enables us to avoid waiting if the resource the completion
5594 * is protecting is not available.
5596 bool try_wait_for_completion(struct completion
*x
)
5600 spin_lock_irq(&x
->wait
.lock
);
5605 spin_unlock_irq(&x
->wait
.lock
);
5608 EXPORT_SYMBOL(try_wait_for_completion
);
5611 * completion_done - Test to see if a completion has any waiters
5612 * @x: completion structure
5614 * Returns: 0 if there are waiters (wait_for_completion() in progress)
5615 * 1 if there are no waiters.
5618 bool completion_done(struct completion
*x
)
5622 spin_lock_irq(&x
->wait
.lock
);
5625 spin_unlock_irq(&x
->wait
.lock
);
5628 EXPORT_SYMBOL(completion_done
);
5631 sleep_on_common(wait_queue_head_t
*q
, int state
, long timeout
)
5633 unsigned long flags
;
5636 init_waitqueue_entry(&wait
, current
);
5638 __set_current_state(state
);
5640 spin_lock_irqsave(&q
->lock
, flags
);
5641 __add_wait_queue(q
, &wait
);
5642 spin_unlock(&q
->lock
);
5643 timeout
= schedule_timeout(timeout
);
5644 spin_lock_irq(&q
->lock
);
5645 __remove_wait_queue(q
, &wait
);
5646 spin_unlock_irqrestore(&q
->lock
, flags
);
5651 void __sched
interruptible_sleep_on(wait_queue_head_t
*q
)
5653 sleep_on_common(q
, TASK_INTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
5655 EXPORT_SYMBOL(interruptible_sleep_on
);
5658 interruptible_sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
5660 return sleep_on_common(q
, TASK_INTERRUPTIBLE
, timeout
);
5662 EXPORT_SYMBOL(interruptible_sleep_on_timeout
);
5664 void __sched
sleep_on(wait_queue_head_t
*q
)
5666 sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
5668 EXPORT_SYMBOL(sleep_on
);
5670 long __sched
sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
5672 return sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, timeout
);
5674 EXPORT_SYMBOL(sleep_on_timeout
);
5676 #ifdef CONFIG_RT_MUTEXES
5679 * rt_mutex_setprio - set the current priority of a task
5681 * @prio: prio value (kernel-internal form)
5683 * This function changes the 'effective' priority of a task. It does
5684 * not touch ->normal_prio like __setscheduler().
5686 * Used by the rt_mutex code to implement priority inheritance logic.
5688 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
5690 unsigned long flags
;
5691 int oldprio
, on_rq
, running
;
5693 const struct sched_class
*prev_class
= p
->sched_class
;
5695 BUG_ON(prio
< 0 || prio
> MAX_PRIO
);
5697 rq
= task_rq_lock(p
, &flags
);
5698 update_rq_clock(rq
);
5701 on_rq
= p
->se
.on_rq
;
5702 running
= task_current(rq
, p
);
5704 dequeue_task(rq
, p
, 0);
5706 p
->sched_class
->put_prev_task(rq
, p
);
5709 p
->sched_class
= &rt_sched_class
;
5711 p
->sched_class
= &fair_sched_class
;
5716 p
->sched_class
->set_curr_task(rq
);
5718 enqueue_task(rq
, p
, 0);
5720 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
5722 task_rq_unlock(rq
, &flags
);
5727 void set_user_nice(struct task_struct
*p
, long nice
)
5729 int old_prio
, delta
, on_rq
;
5730 unsigned long flags
;
5733 if (TASK_NICE(p
) == nice
|| nice
< -20 || nice
> 19)
5736 * We have to be careful, if called from sys_setpriority(),
5737 * the task might be in the middle of scheduling on another CPU.
5739 rq
= task_rq_lock(p
, &flags
);
5740 update_rq_clock(rq
);
5742 * The RT priorities are set via sched_setscheduler(), but we still
5743 * allow the 'normal' nice value to be set - but as expected
5744 * it wont have any effect on scheduling until the task is
5745 * SCHED_FIFO/SCHED_RR:
5747 if (task_has_rt_policy(p
)) {
5748 p
->static_prio
= NICE_TO_PRIO(nice
);
5751 on_rq
= p
->se
.on_rq
;
5753 dequeue_task(rq
, p
, 0);
5755 p
->static_prio
= NICE_TO_PRIO(nice
);
5758 p
->prio
= effective_prio(p
);
5759 delta
= p
->prio
- old_prio
;
5762 enqueue_task(rq
, p
, 0);
5764 * If the task increased its priority or is running and
5765 * lowered its priority, then reschedule its CPU:
5767 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
5768 resched_task(rq
->curr
);
5771 task_rq_unlock(rq
, &flags
);
5773 EXPORT_SYMBOL(set_user_nice
);
5776 * can_nice - check if a task can reduce its nice value
5780 int can_nice(const struct task_struct
*p
, const int nice
)
5782 /* convert nice value [19,-20] to rlimit style value [1,40] */
5783 int nice_rlim
= 20 - nice
;
5785 return (nice_rlim
<= p
->signal
->rlim
[RLIMIT_NICE
].rlim_cur
||
5786 capable(CAP_SYS_NICE
));
5789 #ifdef __ARCH_WANT_SYS_NICE
5792 * sys_nice - change the priority of the current process.
5793 * @increment: priority increment
5795 * sys_setpriority is a more generic, but much slower function that
5796 * does similar things.
5798 SYSCALL_DEFINE1(nice
, int, increment
)
5803 * Setpriority might change our priority at the same moment.
5804 * We don't have to worry. Conceptually one call occurs first
5805 * and we have a single winner.
5807 if (increment
< -40)
5812 nice
= TASK_NICE(current
) + increment
;
5818 if (increment
< 0 && !can_nice(current
, nice
))
5821 retval
= security_task_setnice(current
, nice
);
5825 set_user_nice(current
, nice
);
5832 * task_prio - return the priority value of a given task.
5833 * @p: the task in question.
5835 * This is the priority value as seen by users in /proc.
5836 * RT tasks are offset by -200. Normal tasks are centered
5837 * around 0, value goes from -16 to +15.
5839 int task_prio(const struct task_struct
*p
)
5841 return p
->prio
- MAX_RT_PRIO
;
5845 * task_nice - return the nice value of a given task.
5846 * @p: the task in question.
5848 int task_nice(const struct task_struct
*p
)
5850 return TASK_NICE(p
);
5852 EXPORT_SYMBOL(task_nice
);
5855 * idle_cpu - is a given cpu idle currently?
5856 * @cpu: the processor in question.
5858 int idle_cpu(int cpu
)
5860 return cpu_curr(cpu
) == cpu_rq(cpu
)->idle
;
5864 * idle_task - return the idle task for a given cpu.
5865 * @cpu: the processor in question.
5867 struct task_struct
*idle_task(int cpu
)
5869 return cpu_rq(cpu
)->idle
;
5873 * find_process_by_pid - find a process with a matching PID value.
5874 * @pid: the pid in question.
5876 static struct task_struct
*find_process_by_pid(pid_t pid
)
5878 return pid
? find_task_by_vpid(pid
) : current
;
5881 /* Actually do priority change: must hold rq lock. */
5883 __setscheduler(struct rq
*rq
, struct task_struct
*p
, int policy
, int prio
)
5885 BUG_ON(p
->se
.on_rq
);
5888 switch (p
->policy
) {
5892 p
->sched_class
= &fair_sched_class
;
5896 p
->sched_class
= &rt_sched_class
;
5900 p
->rt_priority
= prio
;
5901 p
->normal_prio
= normal_prio(p
);
5902 /* we are holding p->pi_lock already */
5903 p
->prio
= rt_mutex_getprio(p
);
5908 * check the target process has a UID that matches the current process's
5910 static bool check_same_owner(struct task_struct
*p
)
5912 const struct cred
*cred
= current_cred(), *pcred
;
5916 pcred
= __task_cred(p
);
5917 match
= (cred
->euid
== pcred
->euid
||
5918 cred
->euid
== pcred
->uid
);
5923 static int __sched_setscheduler(struct task_struct
*p
, int policy
,
5924 struct sched_param
*param
, bool user
)
5926 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
5927 unsigned long flags
;
5928 const struct sched_class
*prev_class
= p
->sched_class
;
5931 /* may grab non-irq protected spin_locks */
5932 BUG_ON(in_interrupt());
5934 /* double check policy once rq lock held */
5936 policy
= oldpolicy
= p
->policy
;
5937 else if (policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
5938 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
5939 policy
!= SCHED_IDLE
)
5942 * Valid priorities for SCHED_FIFO and SCHED_RR are
5943 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
5944 * SCHED_BATCH and SCHED_IDLE is 0.
5946 if (param
->sched_priority
< 0 ||
5947 (p
->mm
&& param
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
5948 (!p
->mm
&& param
->sched_priority
> MAX_RT_PRIO
-1))
5950 if (rt_policy(policy
) != (param
->sched_priority
!= 0))
5954 * Allow unprivileged RT tasks to decrease priority:
5956 if (user
&& !capable(CAP_SYS_NICE
)) {
5957 if (rt_policy(policy
)) {
5958 unsigned long rlim_rtprio
;
5960 if (!lock_task_sighand(p
, &flags
))
5962 rlim_rtprio
= p
->signal
->rlim
[RLIMIT_RTPRIO
].rlim_cur
;
5963 unlock_task_sighand(p
, &flags
);
5965 /* can't set/change the rt policy */
5966 if (policy
!= p
->policy
&& !rlim_rtprio
)
5969 /* can't increase priority */
5970 if (param
->sched_priority
> p
->rt_priority
&&
5971 param
->sched_priority
> rlim_rtprio
)
5975 * Like positive nice levels, dont allow tasks to
5976 * move out of SCHED_IDLE either:
5978 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
)
5981 /* can't change other user's priorities */
5982 if (!check_same_owner(p
))
5987 #ifdef CONFIG_RT_GROUP_SCHED
5989 * Do not allow realtime tasks into groups that have no runtime
5992 if (rt_bandwidth_enabled() && rt_policy(policy
) &&
5993 task_group(p
)->rt_bandwidth
.rt_runtime
== 0)
5997 retval
= security_task_setscheduler(p
, policy
, param
);
6003 * make sure no PI-waiters arrive (or leave) while we are
6004 * changing the priority of the task:
6006 spin_lock_irqsave(&p
->pi_lock
, flags
);
6008 * To be able to change p->policy safely, the apropriate
6009 * runqueue lock must be held.
6011 rq
= __task_rq_lock(p
);
6012 /* recheck policy now with rq lock held */
6013 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
6014 policy
= oldpolicy
= -1;
6015 __task_rq_unlock(rq
);
6016 spin_unlock_irqrestore(&p
->pi_lock
, flags
);
6019 update_rq_clock(rq
);
6020 on_rq
= p
->se
.on_rq
;
6021 running
= task_current(rq
, p
);
6023 deactivate_task(rq
, p
, 0);
6025 p
->sched_class
->put_prev_task(rq
, p
);
6028 __setscheduler(rq
, p
, policy
, param
->sched_priority
);
6031 p
->sched_class
->set_curr_task(rq
);
6033 activate_task(rq
, p
, 0);
6035 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
6037 __task_rq_unlock(rq
);
6038 spin_unlock_irqrestore(&p
->pi_lock
, flags
);
6040 rt_mutex_adjust_pi(p
);
6046 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
6047 * @p: the task in question.
6048 * @policy: new policy.
6049 * @param: structure containing the new RT priority.
6051 * NOTE that the task may be already dead.
6053 int sched_setscheduler(struct task_struct
*p
, int policy
,
6054 struct sched_param
*param
)
6056 return __sched_setscheduler(p
, policy
, param
, true);
6058 EXPORT_SYMBOL_GPL(sched_setscheduler
);
6061 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
6062 * @p: the task in question.
6063 * @policy: new policy.
6064 * @param: structure containing the new RT priority.
6066 * Just like sched_setscheduler, only don't bother checking if the
6067 * current context has permission. For example, this is needed in
6068 * stop_machine(): we create temporary high priority worker threads,
6069 * but our caller might not have that capability.
6071 int sched_setscheduler_nocheck(struct task_struct
*p
, int policy
,
6072 struct sched_param
*param
)
6074 return __sched_setscheduler(p
, policy
, param
, false);
6078 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
6080 struct sched_param lparam
;
6081 struct task_struct
*p
;
6084 if (!param
|| pid
< 0)
6086 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
6091 p
= find_process_by_pid(pid
);
6093 retval
= sched_setscheduler(p
, policy
, &lparam
);
6100 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
6101 * @pid: the pid in question.
6102 * @policy: new policy.
6103 * @param: structure containing the new RT priority.
6105 SYSCALL_DEFINE3(sched_setscheduler
, pid_t
, pid
, int, policy
,
6106 struct sched_param __user
*, param
)
6108 /* negative values for policy are not valid */
6112 return do_sched_setscheduler(pid
, policy
, param
);
6116 * sys_sched_setparam - set/change the RT priority of a thread
6117 * @pid: the pid in question.
6118 * @param: structure containing the new RT priority.
6120 SYSCALL_DEFINE2(sched_setparam
, pid_t
, pid
, struct sched_param __user
*, param
)
6122 return do_sched_setscheduler(pid
, -1, param
);
6126 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
6127 * @pid: the pid in question.
6129 SYSCALL_DEFINE1(sched_getscheduler
, pid_t
, pid
)
6131 struct task_struct
*p
;
6138 read_lock(&tasklist_lock
);
6139 p
= find_process_by_pid(pid
);
6141 retval
= security_task_getscheduler(p
);
6145 read_unlock(&tasklist_lock
);
6150 * sys_sched_getscheduler - get the RT priority of a thread
6151 * @pid: the pid in question.
6152 * @param: structure containing the RT priority.
6154 SYSCALL_DEFINE2(sched_getparam
, pid_t
, pid
, struct sched_param __user
*, param
)
6156 struct sched_param lp
;
6157 struct task_struct
*p
;
6160 if (!param
|| pid
< 0)
6163 read_lock(&tasklist_lock
);
6164 p
= find_process_by_pid(pid
);
6169 retval
= security_task_getscheduler(p
);
6173 lp
.sched_priority
= p
->rt_priority
;
6174 read_unlock(&tasklist_lock
);
6177 * This one might sleep, we cannot do it with a spinlock held ...
6179 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
6184 read_unlock(&tasklist_lock
);
6188 long sched_setaffinity(pid_t pid
, const struct cpumask
*in_mask
)
6190 cpumask_var_t cpus_allowed
, new_mask
;
6191 struct task_struct
*p
;
6195 read_lock(&tasklist_lock
);
6197 p
= find_process_by_pid(pid
);
6199 read_unlock(&tasklist_lock
);
6205 * It is not safe to call set_cpus_allowed with the
6206 * tasklist_lock held. We will bump the task_struct's
6207 * usage count and then drop tasklist_lock.
6210 read_unlock(&tasklist_lock
);
6212 if (!alloc_cpumask_var(&cpus_allowed
, GFP_KERNEL
)) {
6216 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
)) {
6218 goto out_free_cpus_allowed
;
6221 if (!check_same_owner(p
) && !capable(CAP_SYS_NICE
))
6224 retval
= security_task_setscheduler(p
, 0, NULL
);
6228 cpuset_cpus_allowed(p
, cpus_allowed
);
6229 cpumask_and(new_mask
, in_mask
, cpus_allowed
);
6231 retval
= set_cpus_allowed_ptr(p
, new_mask
);
6234 cpuset_cpus_allowed(p
, cpus_allowed
);
6235 if (!cpumask_subset(new_mask
, cpus_allowed
)) {
6237 * We must have raced with a concurrent cpuset
6238 * update. Just reset the cpus_allowed to the
6239 * cpuset's cpus_allowed
6241 cpumask_copy(new_mask
, cpus_allowed
);
6246 free_cpumask_var(new_mask
);
6247 out_free_cpus_allowed
:
6248 free_cpumask_var(cpus_allowed
);
6255 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
6256 struct cpumask
*new_mask
)
6258 if (len
< cpumask_size())
6259 cpumask_clear(new_mask
);
6260 else if (len
> cpumask_size())
6261 len
= cpumask_size();
6263 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
6267 * sys_sched_setaffinity - set the cpu affinity of a process
6268 * @pid: pid of the process
6269 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
6270 * @user_mask_ptr: user-space pointer to the new cpu mask
6272 SYSCALL_DEFINE3(sched_setaffinity
, pid_t
, pid
, unsigned int, len
,
6273 unsigned long __user
*, user_mask_ptr
)
6275 cpumask_var_t new_mask
;
6278 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
6281 retval
= get_user_cpu_mask(user_mask_ptr
, len
, new_mask
);
6283 retval
= sched_setaffinity(pid
, new_mask
);
6284 free_cpumask_var(new_mask
);
6288 long sched_getaffinity(pid_t pid
, struct cpumask
*mask
)
6290 struct task_struct
*p
;
6294 read_lock(&tasklist_lock
);
6297 p
= find_process_by_pid(pid
);
6301 retval
= security_task_getscheduler(p
);
6305 cpumask_and(mask
, &p
->cpus_allowed
, cpu_online_mask
);
6308 read_unlock(&tasklist_lock
);
6315 * sys_sched_getaffinity - get the cpu affinity of a process
6316 * @pid: pid of the process
6317 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
6318 * @user_mask_ptr: user-space pointer to hold the current cpu mask
6320 SYSCALL_DEFINE3(sched_getaffinity
, pid_t
, pid
, unsigned int, len
,
6321 unsigned long __user
*, user_mask_ptr
)
6326 if (len
< cpumask_size())
6329 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
6332 ret
= sched_getaffinity(pid
, mask
);
6334 if (copy_to_user(user_mask_ptr
, mask
, cpumask_size()))
6337 ret
= cpumask_size();
6339 free_cpumask_var(mask
);
6345 * sys_sched_yield - yield the current processor to other threads.
6347 * This function yields the current CPU to other tasks. If there are no
6348 * other threads running on this CPU then this function will return.
6350 SYSCALL_DEFINE0(sched_yield
)
6352 struct rq
*rq
= this_rq_lock();
6354 schedstat_inc(rq
, yld_count
);
6355 current
->sched_class
->yield_task(rq
);
6358 * Since we are going to call schedule() anyway, there's
6359 * no need to preempt or enable interrupts:
6361 __release(rq
->lock
);
6362 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
6363 _raw_spin_unlock(&rq
->lock
);
6364 preempt_enable_no_resched();
6371 static void __cond_resched(void)
6373 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
6374 __might_sleep(__FILE__
, __LINE__
);
6377 * The BKS might be reacquired before we have dropped
6378 * PREEMPT_ACTIVE, which could trigger a second
6379 * cond_resched() call.
6382 add_preempt_count(PREEMPT_ACTIVE
);
6384 sub_preempt_count(PREEMPT_ACTIVE
);
6385 } while (need_resched());
6388 int __sched
_cond_resched(void)
6390 if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE
) &&
6391 system_state
== SYSTEM_RUNNING
) {
6397 EXPORT_SYMBOL(_cond_resched
);
6400 * cond_resched_lock() - if a reschedule is pending, drop the given lock,
6401 * call schedule, and on return reacquire the lock.
6403 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
6404 * operations here to prevent schedule() from being called twice (once via
6405 * spin_unlock(), once by hand).
6407 int cond_resched_lock(spinlock_t
*lock
)
6409 int resched
= need_resched() && system_state
== SYSTEM_RUNNING
;
6412 if (spin_needbreak(lock
) || resched
) {
6414 if (resched
&& need_resched())
6423 EXPORT_SYMBOL(cond_resched_lock
);
6425 int __sched
cond_resched_softirq(void)
6427 BUG_ON(!in_softirq());
6429 if (need_resched() && system_state
== SYSTEM_RUNNING
) {
6437 EXPORT_SYMBOL(cond_resched_softirq
);
6440 * yield - yield the current processor to other threads.
6442 * This is a shortcut for kernel-space yielding - it marks the
6443 * thread runnable and calls sys_sched_yield().
6445 void __sched
yield(void)
6447 set_current_state(TASK_RUNNING
);
6450 EXPORT_SYMBOL(yield
);
6453 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
6454 * that process accounting knows that this is a task in IO wait state.
6456 * But don't do that if it is a deliberate, throttling IO wait (this task
6457 * has set its backing_dev_info: the queue against which it should throttle)
6459 void __sched
io_schedule(void)
6461 struct rq
*rq
= &__raw_get_cpu_var(runqueues
);
6463 delayacct_blkio_start();
6464 atomic_inc(&rq
->nr_iowait
);
6466 atomic_dec(&rq
->nr_iowait
);
6467 delayacct_blkio_end();
6469 EXPORT_SYMBOL(io_schedule
);
6471 long __sched
io_schedule_timeout(long timeout
)
6473 struct rq
*rq
= &__raw_get_cpu_var(runqueues
);
6476 delayacct_blkio_start();
6477 atomic_inc(&rq
->nr_iowait
);
6478 ret
= schedule_timeout(timeout
);
6479 atomic_dec(&rq
->nr_iowait
);
6480 delayacct_blkio_end();
6485 * sys_sched_get_priority_max - return maximum RT priority.
6486 * @policy: scheduling class.
6488 * this syscall returns the maximum rt_priority that can be used
6489 * by a given scheduling class.
6491 SYSCALL_DEFINE1(sched_get_priority_max
, int, policy
)
6498 ret
= MAX_USER_RT_PRIO
-1;
6510 * sys_sched_get_priority_min - return minimum RT priority.
6511 * @policy: scheduling class.
6513 * this syscall returns the minimum rt_priority that can be used
6514 * by a given scheduling class.
6516 SYSCALL_DEFINE1(sched_get_priority_min
, int, policy
)
6534 * sys_sched_rr_get_interval - return the default timeslice of a process.
6535 * @pid: pid of the process.
6536 * @interval: userspace pointer to the timeslice value.
6538 * this syscall writes the default timeslice value of a given process
6539 * into the user-space timespec buffer. A value of '0' means infinity.
6541 SYSCALL_DEFINE2(sched_rr_get_interval
, pid_t
, pid
,
6542 struct timespec __user
*, interval
)
6544 struct task_struct
*p
;
6545 unsigned int time_slice
;
6553 read_lock(&tasklist_lock
);
6554 p
= find_process_by_pid(pid
);
6558 retval
= security_task_getscheduler(p
);
6563 * Time slice is 0 for SCHED_FIFO tasks and for SCHED_OTHER
6564 * tasks that are on an otherwise idle runqueue:
6567 if (p
->policy
== SCHED_RR
) {
6568 time_slice
= DEF_TIMESLICE
;
6569 } else if (p
->policy
!= SCHED_FIFO
) {
6570 struct sched_entity
*se
= &p
->se
;
6571 unsigned long flags
;
6574 rq
= task_rq_lock(p
, &flags
);
6575 if (rq
->cfs
.load
.weight
)
6576 time_slice
= NS_TO_JIFFIES(sched_slice(&rq
->cfs
, se
));
6577 task_rq_unlock(rq
, &flags
);
6579 read_unlock(&tasklist_lock
);
6580 jiffies_to_timespec(time_slice
, &t
);
6581 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
6585 read_unlock(&tasklist_lock
);
6589 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
6591 void sched_show_task(struct task_struct
*p
)
6593 unsigned long free
= 0;
6596 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
6597 printk(KERN_INFO
"%-13.13s %c", p
->comm
,
6598 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
6599 #if BITS_PER_LONG == 32
6600 if (state
== TASK_RUNNING
)
6601 printk(KERN_CONT
" running ");
6603 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
6605 if (state
== TASK_RUNNING
)
6606 printk(KERN_CONT
" running task ");
6608 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
6610 #ifdef CONFIG_DEBUG_STACK_USAGE
6611 free
= stack_not_used(p
);
6613 printk(KERN_CONT
"%5lu %5d %6d 0x%08lx\n", free
,
6614 task_pid_nr(p
), task_pid_nr(p
->real_parent
),
6615 (unsigned long)task_thread_info(p
)->flags
);
6617 show_stack(p
, NULL
);
6620 void show_state_filter(unsigned long state_filter
)
6622 struct task_struct
*g
, *p
;
6624 #if BITS_PER_LONG == 32
6626 " task PC stack pid father\n");
6629 " task PC stack pid father\n");
6631 read_lock(&tasklist_lock
);
6632 do_each_thread(g
, p
) {
6634 * reset the NMI-timeout, listing all files on a slow
6635 * console might take alot of time:
6637 touch_nmi_watchdog();
6638 if (!state_filter
|| (p
->state
& state_filter
))
6640 } while_each_thread(g
, p
);
6642 touch_all_softlockup_watchdogs();
6644 #ifdef CONFIG_SCHED_DEBUG
6645 sysrq_sched_debug_show();
6647 read_unlock(&tasklist_lock
);
6649 * Only show locks if all tasks are dumped:
6651 if (state_filter
== -1)
6652 debug_show_all_locks();
6655 void __cpuinit
init_idle_bootup_task(struct task_struct
*idle
)
6657 idle
->sched_class
= &idle_sched_class
;
6661 * init_idle - set up an idle thread for a given CPU
6662 * @idle: task in question
6663 * @cpu: cpu the idle task belongs to
6665 * NOTE: this function does not set the idle thread's NEED_RESCHED
6666 * flag, to make booting more robust.
6668 void __cpuinit
init_idle(struct task_struct
*idle
, int cpu
)
6670 struct rq
*rq
= cpu_rq(cpu
);
6671 unsigned long flags
;
6673 spin_lock_irqsave(&rq
->lock
, flags
);
6676 idle
->se
.exec_start
= sched_clock();
6678 idle
->prio
= idle
->normal_prio
= MAX_PRIO
;
6679 cpumask_copy(&idle
->cpus_allowed
, cpumask_of(cpu
));
6680 __set_task_cpu(idle
, cpu
);
6682 rq
->curr
= rq
->idle
= idle
;
6683 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
6686 spin_unlock_irqrestore(&rq
->lock
, flags
);
6688 /* Set the preempt count _outside_ the spinlocks! */
6689 #if defined(CONFIG_PREEMPT)
6690 task_thread_info(idle
)->preempt_count
= (idle
->lock_depth
>= 0);
6692 task_thread_info(idle
)->preempt_count
= 0;
6695 * The idle tasks have their own, simple scheduling class:
6697 idle
->sched_class
= &idle_sched_class
;
6698 ftrace_graph_init_task(idle
);
6702 * In a system that switches off the HZ timer nohz_cpu_mask
6703 * indicates which cpus entered this state. This is used
6704 * in the rcu update to wait only for active cpus. For system
6705 * which do not switch off the HZ timer nohz_cpu_mask should
6706 * always be CPU_BITS_NONE.
6708 cpumask_var_t nohz_cpu_mask
;
6711 * Increase the granularity value when there are more CPUs,
6712 * because with more CPUs the 'effective latency' as visible
6713 * to users decreases. But the relationship is not linear,
6714 * so pick a second-best guess by going with the log2 of the
6717 * This idea comes from the SD scheduler of Con Kolivas:
6719 static inline void sched_init_granularity(void)
6721 unsigned int factor
= 1 + ilog2(num_online_cpus());
6722 const unsigned long limit
= 200000000;
6724 sysctl_sched_min_granularity
*= factor
;
6725 if (sysctl_sched_min_granularity
> limit
)
6726 sysctl_sched_min_granularity
= limit
;
6728 sysctl_sched_latency
*= factor
;
6729 if (sysctl_sched_latency
> limit
)
6730 sysctl_sched_latency
= limit
;
6732 sysctl_sched_wakeup_granularity
*= factor
;
6734 sysctl_sched_shares_ratelimit
*= factor
;
6739 * This is how migration works:
6741 * 1) we queue a struct migration_req structure in the source CPU's
6742 * runqueue and wake up that CPU's migration thread.
6743 * 2) we down() the locked semaphore => thread blocks.
6744 * 3) migration thread wakes up (implicitly it forces the migrated
6745 * thread off the CPU)
6746 * 4) it gets the migration request and checks whether the migrated
6747 * task is still in the wrong runqueue.
6748 * 5) if it's in the wrong runqueue then the migration thread removes
6749 * it and puts it into the right queue.
6750 * 6) migration thread up()s the semaphore.
6751 * 7) we wake up and the migration is done.
6755 * Change a given task's CPU affinity. Migrate the thread to a
6756 * proper CPU and schedule it away if the CPU it's executing on
6757 * is removed from the allowed bitmask.
6759 * NOTE: the caller must have a valid reference to the task, the
6760 * task must not exit() & deallocate itself prematurely. The
6761 * call is not atomic; no spinlocks may be held.
6763 int set_cpus_allowed_ptr(struct task_struct
*p
, const struct cpumask
*new_mask
)
6765 struct migration_req req
;
6766 unsigned long flags
;
6770 rq
= task_rq_lock(p
, &flags
);
6771 if (!cpumask_intersects(new_mask
, cpu_online_mask
)) {
6776 if (unlikely((p
->flags
& PF_THREAD_BOUND
) && p
!= current
&&
6777 !cpumask_equal(&p
->cpus_allowed
, new_mask
))) {
6782 if (p
->sched_class
->set_cpus_allowed
)
6783 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
6785 cpumask_copy(&p
->cpus_allowed
, new_mask
);
6786 p
->rt
.nr_cpus_allowed
= cpumask_weight(new_mask
);
6789 /* Can the task run on the task's current CPU? If so, we're done */
6790 if (cpumask_test_cpu(task_cpu(p
), new_mask
))
6793 if (migrate_task(p
, cpumask_any_and(cpu_online_mask
, new_mask
), &req
)) {
6794 /* Need help from migration thread: drop lock and wait. */
6795 task_rq_unlock(rq
, &flags
);
6796 wake_up_process(rq
->migration_thread
);
6797 wait_for_completion(&req
.done
);
6798 tlb_migrate_finish(p
->mm
);
6802 task_rq_unlock(rq
, &flags
);
6806 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
6809 * Move (not current) task off this cpu, onto dest cpu. We're doing
6810 * this because either it can't run here any more (set_cpus_allowed()
6811 * away from this CPU, or CPU going down), or because we're
6812 * attempting to rebalance this task on exec (sched_exec).
6814 * So we race with normal scheduler movements, but that's OK, as long
6815 * as the task is no longer on this CPU.
6817 * Returns non-zero if task was successfully migrated.
6819 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
6821 struct rq
*rq_dest
, *rq_src
;
6824 if (unlikely(!cpu_active(dest_cpu
)))
6827 rq_src
= cpu_rq(src_cpu
);
6828 rq_dest
= cpu_rq(dest_cpu
);
6830 double_rq_lock(rq_src
, rq_dest
);
6831 /* Already moved. */
6832 if (task_cpu(p
) != src_cpu
)
6834 /* Affinity changed (again). */
6835 if (!cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
6838 on_rq
= p
->se
.on_rq
;
6840 deactivate_task(rq_src
, p
, 0);
6842 set_task_cpu(p
, dest_cpu
);
6844 activate_task(rq_dest
, p
, 0);
6845 check_preempt_curr(rq_dest
, p
, 0);
6850 double_rq_unlock(rq_src
, rq_dest
);
6855 * migration_thread - this is a highprio system thread that performs
6856 * thread migration by bumping thread off CPU then 'pushing' onto
6859 static int migration_thread(void *data
)
6861 int cpu
= (long)data
;
6865 BUG_ON(rq
->migration_thread
!= current
);
6867 set_current_state(TASK_INTERRUPTIBLE
);
6868 while (!kthread_should_stop()) {
6869 struct migration_req
*req
;
6870 struct list_head
*head
;
6872 spin_lock_irq(&rq
->lock
);
6874 if (cpu_is_offline(cpu
)) {
6875 spin_unlock_irq(&rq
->lock
);
6879 if (rq
->active_balance
) {
6880 active_load_balance(rq
, cpu
);
6881 rq
->active_balance
= 0;
6884 head
= &rq
->migration_queue
;
6886 if (list_empty(head
)) {
6887 spin_unlock_irq(&rq
->lock
);
6889 set_current_state(TASK_INTERRUPTIBLE
);
6892 req
= list_entry(head
->next
, struct migration_req
, list
);
6893 list_del_init(head
->next
);
6895 spin_unlock(&rq
->lock
);
6896 __migrate_task(req
->task
, cpu
, req
->dest_cpu
);
6899 complete(&req
->done
);
6901 __set_current_state(TASK_RUNNING
);
6905 /* Wait for kthread_stop */
6906 set_current_state(TASK_INTERRUPTIBLE
);
6907 while (!kthread_should_stop()) {
6909 set_current_state(TASK_INTERRUPTIBLE
);
6911 __set_current_state(TASK_RUNNING
);
6915 #ifdef CONFIG_HOTPLUG_CPU
6917 static int __migrate_task_irq(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
6921 local_irq_disable();
6922 ret
= __migrate_task(p
, src_cpu
, dest_cpu
);
6928 * Figure out where task on dead CPU should go, use force if necessary.
6930 static void move_task_off_dead_cpu(int dead_cpu
, struct task_struct
*p
)
6933 const struct cpumask
*nodemask
= cpumask_of_node(cpu_to_node(dead_cpu
));
6936 /* Look for allowed, online CPU in same node. */
6937 for_each_cpu_and(dest_cpu
, nodemask
, cpu_online_mask
)
6938 if (cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
6941 /* Any allowed, online CPU? */
6942 dest_cpu
= cpumask_any_and(&p
->cpus_allowed
, cpu_online_mask
);
6943 if (dest_cpu
< nr_cpu_ids
)
6946 /* No more Mr. Nice Guy. */
6947 if (dest_cpu
>= nr_cpu_ids
) {
6948 cpuset_cpus_allowed_locked(p
, &p
->cpus_allowed
);
6949 dest_cpu
= cpumask_any_and(cpu_online_mask
, &p
->cpus_allowed
);
6952 * Don't tell them about moving exiting tasks or
6953 * kernel threads (both mm NULL), since they never
6956 if (p
->mm
&& printk_ratelimit()) {
6957 printk(KERN_INFO
"process %d (%s) no "
6958 "longer affine to cpu%d\n",
6959 task_pid_nr(p
), p
->comm
, dead_cpu
);
6964 /* It can have affinity changed while we were choosing. */
6965 if (unlikely(!__migrate_task_irq(p
, dead_cpu
, dest_cpu
)))
6970 * While a dead CPU has no uninterruptible tasks queued at this point,
6971 * it might still have a nonzero ->nr_uninterruptible counter, because
6972 * for performance reasons the counter is not stricly tracking tasks to
6973 * their home CPUs. So we just add the counter to another CPU's counter,
6974 * to keep the global sum constant after CPU-down:
6976 static void migrate_nr_uninterruptible(struct rq
*rq_src
)
6978 struct rq
*rq_dest
= cpu_rq(cpumask_any(cpu_online_mask
));
6979 unsigned long flags
;
6981 local_irq_save(flags
);
6982 double_rq_lock(rq_src
, rq_dest
);
6983 rq_dest
->nr_uninterruptible
+= rq_src
->nr_uninterruptible
;
6984 rq_src
->nr_uninterruptible
= 0;
6985 double_rq_unlock(rq_src
, rq_dest
);
6986 local_irq_restore(flags
);
6989 /* Run through task list and migrate tasks from the dead cpu. */
6990 static void migrate_live_tasks(int src_cpu
)
6992 struct task_struct
*p
, *t
;
6994 read_lock(&tasklist_lock
);
6996 do_each_thread(t
, p
) {
7000 if (task_cpu(p
) == src_cpu
)
7001 move_task_off_dead_cpu(src_cpu
, p
);
7002 } while_each_thread(t
, p
);
7004 read_unlock(&tasklist_lock
);
7008 * Schedules idle task to be the next runnable task on current CPU.
7009 * It does so by boosting its priority to highest possible.
7010 * Used by CPU offline code.
7012 void sched_idle_next(void)
7014 int this_cpu
= smp_processor_id();
7015 struct rq
*rq
= cpu_rq(this_cpu
);
7016 struct task_struct
*p
= rq
->idle
;
7017 unsigned long flags
;
7019 /* cpu has to be offline */
7020 BUG_ON(cpu_online(this_cpu
));
7023 * Strictly not necessary since rest of the CPUs are stopped by now
7024 * and interrupts disabled on the current cpu.
7026 spin_lock_irqsave(&rq
->lock
, flags
);
7028 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
7030 update_rq_clock(rq
);
7031 activate_task(rq
, p
, 0);
7033 spin_unlock_irqrestore(&rq
->lock
, flags
);
7037 * Ensures that the idle task is using init_mm right before its cpu goes
7040 void idle_task_exit(void)
7042 struct mm_struct
*mm
= current
->active_mm
;
7044 BUG_ON(cpu_online(smp_processor_id()));
7047 switch_mm(mm
, &init_mm
, current
);
7051 /* called under rq->lock with disabled interrupts */
7052 static void migrate_dead(unsigned int dead_cpu
, struct task_struct
*p
)
7054 struct rq
*rq
= cpu_rq(dead_cpu
);
7056 /* Must be exiting, otherwise would be on tasklist. */
7057 BUG_ON(!p
->exit_state
);
7059 /* Cannot have done final schedule yet: would have vanished. */
7060 BUG_ON(p
->state
== TASK_DEAD
);
7065 * Drop lock around migration; if someone else moves it,
7066 * that's OK. No task can be added to this CPU, so iteration is
7069 spin_unlock_irq(&rq
->lock
);
7070 move_task_off_dead_cpu(dead_cpu
, p
);
7071 spin_lock_irq(&rq
->lock
);
7076 /* release_task() removes task from tasklist, so we won't find dead tasks. */
7077 static void migrate_dead_tasks(unsigned int dead_cpu
)
7079 struct rq
*rq
= cpu_rq(dead_cpu
);
7080 struct task_struct
*next
;
7083 if (!rq
->nr_running
)
7085 update_rq_clock(rq
);
7086 next
= pick_next_task(rq
);
7089 next
->sched_class
->put_prev_task(rq
, next
);
7090 migrate_dead(dead_cpu
, next
);
7094 #endif /* CONFIG_HOTPLUG_CPU */
7096 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
7098 static struct ctl_table sd_ctl_dir
[] = {
7100 .procname
= "sched_domain",
7106 static struct ctl_table sd_ctl_root
[] = {
7108 .ctl_name
= CTL_KERN
,
7109 .procname
= "kernel",
7111 .child
= sd_ctl_dir
,
7116 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
7118 struct ctl_table
*entry
=
7119 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
7124 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
7126 struct ctl_table
*entry
;
7129 * In the intermediate directories, both the child directory and
7130 * procname are dynamically allocated and could fail but the mode
7131 * will always be set. In the lowest directory the names are
7132 * static strings and all have proc handlers.
7134 for (entry
= *tablep
; entry
->mode
; entry
++) {
7136 sd_free_ctl_entry(&entry
->child
);
7137 if (entry
->proc_handler
== NULL
)
7138 kfree(entry
->procname
);
7146 set_table_entry(struct ctl_table
*entry
,
7147 const char *procname
, void *data
, int maxlen
,
7148 mode_t mode
, proc_handler
*proc_handler
)
7150 entry
->procname
= procname
;
7152 entry
->maxlen
= maxlen
;
7154 entry
->proc_handler
= proc_handler
;
7157 static struct ctl_table
*
7158 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
7160 struct ctl_table
*table
= sd_alloc_ctl_entry(13);
7165 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
7166 sizeof(long), 0644, proc_doulongvec_minmax
);
7167 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
7168 sizeof(long), 0644, proc_doulongvec_minmax
);
7169 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
7170 sizeof(int), 0644, proc_dointvec_minmax
);
7171 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
7172 sizeof(int), 0644, proc_dointvec_minmax
);
7173 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
7174 sizeof(int), 0644, proc_dointvec_minmax
);
7175 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
7176 sizeof(int), 0644, proc_dointvec_minmax
);
7177 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
7178 sizeof(int), 0644, proc_dointvec_minmax
);
7179 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
7180 sizeof(int), 0644, proc_dointvec_minmax
);
7181 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
7182 sizeof(int), 0644, proc_dointvec_minmax
);
7183 set_table_entry(&table
[9], "cache_nice_tries",
7184 &sd
->cache_nice_tries
,
7185 sizeof(int), 0644, proc_dointvec_minmax
);
7186 set_table_entry(&table
[10], "flags", &sd
->flags
,
7187 sizeof(int), 0644, proc_dointvec_minmax
);
7188 set_table_entry(&table
[11], "name", sd
->name
,
7189 CORENAME_MAX_SIZE
, 0444, proc_dostring
);
7190 /* &table[12] is terminator */
7195 static ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
7197 struct ctl_table
*entry
, *table
;
7198 struct sched_domain
*sd
;
7199 int domain_num
= 0, i
;
7202 for_each_domain(cpu
, sd
)
7204 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
7209 for_each_domain(cpu
, sd
) {
7210 snprintf(buf
, 32, "domain%d", i
);
7211 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
7213 entry
->child
= sd_alloc_ctl_domain_table(sd
);
7220 static struct ctl_table_header
*sd_sysctl_header
;
7221 static void register_sched_domain_sysctl(void)
7223 int i
, cpu_num
= num_online_cpus();
7224 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
7227 WARN_ON(sd_ctl_dir
[0].child
);
7228 sd_ctl_dir
[0].child
= entry
;
7233 for_each_online_cpu(i
) {
7234 snprintf(buf
, 32, "cpu%d", i
);
7235 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
7237 entry
->child
= sd_alloc_ctl_cpu_table(i
);
7241 WARN_ON(sd_sysctl_header
);
7242 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
7245 /* may be called multiple times per register */
7246 static void unregister_sched_domain_sysctl(void)
7248 if (sd_sysctl_header
)
7249 unregister_sysctl_table(sd_sysctl_header
);
7250 sd_sysctl_header
= NULL
;
7251 if (sd_ctl_dir
[0].child
)
7252 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
7255 static void register_sched_domain_sysctl(void)
7258 static void unregister_sched_domain_sysctl(void)
7263 static void set_rq_online(struct rq
*rq
)
7266 const struct sched_class
*class;
7268 cpumask_set_cpu(rq
->cpu
, rq
->rd
->online
);
7271 for_each_class(class) {
7272 if (class->rq_online
)
7273 class->rq_online(rq
);
7278 static void set_rq_offline(struct rq
*rq
)
7281 const struct sched_class
*class;
7283 for_each_class(class) {
7284 if (class->rq_offline
)
7285 class->rq_offline(rq
);
7288 cpumask_clear_cpu(rq
->cpu
, rq
->rd
->online
);
7294 * migration_call - callback that gets triggered when a CPU is added.
7295 * Here we can start up the necessary migration thread for the new CPU.
7297 static int __cpuinit
7298 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
7300 struct task_struct
*p
;
7301 int cpu
= (long)hcpu
;
7302 unsigned long flags
;
7307 case CPU_UP_PREPARE
:
7308 case CPU_UP_PREPARE_FROZEN
:
7309 p
= kthread_create(migration_thread
, hcpu
, "migration/%d", cpu
);
7312 kthread_bind(p
, cpu
);
7313 /* Must be high prio: stop_machine expects to yield to it. */
7314 rq
= task_rq_lock(p
, &flags
);
7315 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
7316 task_rq_unlock(rq
, &flags
);
7317 cpu_rq(cpu
)->migration_thread
= p
;
7321 case CPU_ONLINE_FROZEN
:
7322 /* Strictly unnecessary, as first user will wake it. */
7323 wake_up_process(cpu_rq(cpu
)->migration_thread
);
7325 /* Update our root-domain */
7327 spin_lock_irqsave(&rq
->lock
, flags
);
7329 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
7333 spin_unlock_irqrestore(&rq
->lock
, flags
);
7336 #ifdef CONFIG_HOTPLUG_CPU
7337 case CPU_UP_CANCELED
:
7338 case CPU_UP_CANCELED_FROZEN
:
7339 if (!cpu_rq(cpu
)->migration_thread
)
7341 /* Unbind it from offline cpu so it can run. Fall thru. */
7342 kthread_bind(cpu_rq(cpu
)->migration_thread
,
7343 cpumask_any(cpu_online_mask
));
7344 kthread_stop(cpu_rq(cpu
)->migration_thread
);
7345 cpu_rq(cpu
)->migration_thread
= NULL
;
7349 case CPU_DEAD_FROZEN
:
7350 cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */
7351 migrate_live_tasks(cpu
);
7353 kthread_stop(rq
->migration_thread
);
7354 rq
->migration_thread
= NULL
;
7355 /* Idle task back to normal (off runqueue, low prio) */
7356 spin_lock_irq(&rq
->lock
);
7357 update_rq_clock(rq
);
7358 deactivate_task(rq
, rq
->idle
, 0);
7359 rq
->idle
->static_prio
= MAX_PRIO
;
7360 __setscheduler(rq
, rq
->idle
, SCHED_NORMAL
, 0);
7361 rq
->idle
->sched_class
= &idle_sched_class
;
7362 migrate_dead_tasks(cpu
);
7363 spin_unlock_irq(&rq
->lock
);
7365 migrate_nr_uninterruptible(rq
);
7366 BUG_ON(rq
->nr_running
!= 0);
7369 * No need to migrate the tasks: it was best-effort if
7370 * they didn't take sched_hotcpu_mutex. Just wake up
7373 spin_lock_irq(&rq
->lock
);
7374 while (!list_empty(&rq
->migration_queue
)) {
7375 struct migration_req
*req
;
7377 req
= list_entry(rq
->migration_queue
.next
,
7378 struct migration_req
, list
);
7379 list_del_init(&req
->list
);
7380 spin_unlock_irq(&rq
->lock
);
7381 complete(&req
->done
);
7382 spin_lock_irq(&rq
->lock
);
7384 spin_unlock_irq(&rq
->lock
);
7388 case CPU_DYING_FROZEN
:
7389 /* Update our root-domain */
7391 spin_lock_irqsave(&rq
->lock
, flags
);
7393 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
7396 spin_unlock_irqrestore(&rq
->lock
, flags
);
7403 /* Register at highest priority so that task migration (migrate_all_tasks)
7404 * happens before everything else.
7406 static struct notifier_block __cpuinitdata migration_notifier
= {
7407 .notifier_call
= migration_call
,
7411 static int __init
migration_init(void)
7413 void *cpu
= (void *)(long)smp_processor_id();
7416 /* Start one for the boot CPU: */
7417 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
7418 BUG_ON(err
== NOTIFY_BAD
);
7419 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
7420 register_cpu_notifier(&migration_notifier
);
7424 early_initcall(migration_init
);
7429 #ifdef CONFIG_SCHED_DEBUG
7431 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
7432 struct cpumask
*groupmask
)
7434 struct sched_group
*group
= sd
->groups
;
7437 cpulist_scnprintf(str
, sizeof(str
), sched_domain_span(sd
));
7438 cpumask_clear(groupmask
);
7440 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
7442 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
7443 printk("does not load-balance\n");
7445 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
7450 printk(KERN_CONT
"span %s level %s\n", str
, sd
->name
);
7452 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
7453 printk(KERN_ERR
"ERROR: domain->span does not contain "
7456 if (!cpumask_test_cpu(cpu
, sched_group_cpus(group
))) {
7457 printk(KERN_ERR
"ERROR: domain->groups does not contain"
7461 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
7465 printk(KERN_ERR
"ERROR: group is NULL\n");
7469 if (!group
->__cpu_power
) {
7470 printk(KERN_CONT
"\n");
7471 printk(KERN_ERR
"ERROR: domain->cpu_power not "
7476 if (!cpumask_weight(sched_group_cpus(group
))) {
7477 printk(KERN_CONT
"\n");
7478 printk(KERN_ERR
"ERROR: empty group\n");
7482 if (cpumask_intersects(groupmask
, sched_group_cpus(group
))) {
7483 printk(KERN_CONT
"\n");
7484 printk(KERN_ERR
"ERROR: repeated CPUs\n");
7488 cpumask_or(groupmask
, groupmask
, sched_group_cpus(group
));
7490 cpulist_scnprintf(str
, sizeof(str
), sched_group_cpus(group
));
7492 printk(KERN_CONT
" %s", str
);
7493 if (group
->__cpu_power
!= SCHED_LOAD_SCALE
) {
7494 printk(KERN_CONT
" (__cpu_power = %d)",
7495 group
->__cpu_power
);
7498 group
= group
->next
;
7499 } while (group
!= sd
->groups
);
7500 printk(KERN_CONT
"\n");
7502 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
7503 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
7506 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
7507 printk(KERN_ERR
"ERROR: parent span is not a superset "
7508 "of domain->span\n");
7512 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
7514 cpumask_var_t groupmask
;
7518 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
7522 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
7524 if (!alloc_cpumask_var(&groupmask
, GFP_KERNEL
)) {
7525 printk(KERN_DEBUG
"Cannot load-balance (out of memory)\n");
7530 if (sched_domain_debug_one(sd
, cpu
, level
, groupmask
))
7537 free_cpumask_var(groupmask
);
7539 #else /* !CONFIG_SCHED_DEBUG */
7540 # define sched_domain_debug(sd, cpu) do { } while (0)
7541 #endif /* CONFIG_SCHED_DEBUG */
7543 static int sd_degenerate(struct sched_domain
*sd
)
7545 if (cpumask_weight(sched_domain_span(sd
)) == 1)
7548 /* Following flags need at least 2 groups */
7549 if (sd
->flags
& (SD_LOAD_BALANCE
|
7550 SD_BALANCE_NEWIDLE
|
7554 SD_SHARE_PKG_RESOURCES
)) {
7555 if (sd
->groups
!= sd
->groups
->next
)
7559 /* Following flags don't use groups */
7560 if (sd
->flags
& (SD_WAKE_IDLE
|
7569 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
7571 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
7573 if (sd_degenerate(parent
))
7576 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
7579 /* Does parent contain flags not in child? */
7580 /* WAKE_BALANCE is a subset of WAKE_AFFINE */
7581 if (cflags
& SD_WAKE_AFFINE
)
7582 pflags
&= ~SD_WAKE_BALANCE
;
7583 /* Flags needing groups don't count if only 1 group in parent */
7584 if (parent
->groups
== parent
->groups
->next
) {
7585 pflags
&= ~(SD_LOAD_BALANCE
|
7586 SD_BALANCE_NEWIDLE
|
7590 SD_SHARE_PKG_RESOURCES
);
7591 if (nr_node_ids
== 1)
7592 pflags
&= ~SD_SERIALIZE
;
7594 if (~cflags
& pflags
)
7600 static void free_rootdomain(struct root_domain
*rd
)
7602 cpupri_cleanup(&rd
->cpupri
);
7604 free_cpumask_var(rd
->rto_mask
);
7605 free_cpumask_var(rd
->online
);
7606 free_cpumask_var(rd
->span
);
7610 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
7612 struct root_domain
*old_rd
= NULL
;
7613 unsigned long flags
;
7615 spin_lock_irqsave(&rq
->lock
, flags
);
7620 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
7623 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
7626 * If we dont want to free the old_rt yet then
7627 * set old_rd to NULL to skip the freeing later
7630 if (!atomic_dec_and_test(&old_rd
->refcount
))
7634 atomic_inc(&rd
->refcount
);
7637 cpumask_set_cpu(rq
->cpu
, rd
->span
);
7638 if (cpumask_test_cpu(rq
->cpu
, cpu_online_mask
))
7641 spin_unlock_irqrestore(&rq
->lock
, flags
);
7644 free_rootdomain(old_rd
);
7647 static int __init_refok
init_rootdomain(struct root_domain
*rd
, bool bootmem
)
7649 memset(rd
, 0, sizeof(*rd
));
7652 alloc_bootmem_cpumask_var(&def_root_domain
.span
);
7653 alloc_bootmem_cpumask_var(&def_root_domain
.online
);
7654 alloc_bootmem_cpumask_var(&def_root_domain
.rto_mask
);
7655 cpupri_init(&rd
->cpupri
, true);
7659 if (!alloc_cpumask_var(&rd
->span
, GFP_KERNEL
))
7661 if (!alloc_cpumask_var(&rd
->online
, GFP_KERNEL
))
7663 if (!alloc_cpumask_var(&rd
->rto_mask
, GFP_KERNEL
))
7666 if (cpupri_init(&rd
->cpupri
, false) != 0)
7671 free_cpumask_var(rd
->rto_mask
);
7673 free_cpumask_var(rd
->online
);
7675 free_cpumask_var(rd
->span
);
7680 static void init_defrootdomain(void)
7682 init_rootdomain(&def_root_domain
, true);
7684 atomic_set(&def_root_domain
.refcount
, 1);
7687 static struct root_domain
*alloc_rootdomain(void)
7689 struct root_domain
*rd
;
7691 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
7695 if (init_rootdomain(rd
, false) != 0) {
7704 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
7705 * hold the hotplug lock.
7708 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
7710 struct rq
*rq
= cpu_rq(cpu
);
7711 struct sched_domain
*tmp
;
7713 /* Remove the sched domains which do not contribute to scheduling. */
7714 for (tmp
= sd
; tmp
; ) {
7715 struct sched_domain
*parent
= tmp
->parent
;
7719 if (sd_parent_degenerate(tmp
, parent
)) {
7720 tmp
->parent
= parent
->parent
;
7722 parent
->parent
->child
= tmp
;
7727 if (sd
&& sd_degenerate(sd
)) {
7733 sched_domain_debug(sd
, cpu
);
7735 rq_attach_root(rq
, rd
);
7736 rcu_assign_pointer(rq
->sd
, sd
);
7739 /* cpus with isolated domains */
7740 static cpumask_var_t cpu_isolated_map
;
7742 /* Setup the mask of cpus configured for isolated domains */
7743 static int __init
isolated_cpu_setup(char *str
)
7745 cpulist_parse(str
, cpu_isolated_map
);
7749 __setup("isolcpus=", isolated_cpu_setup
);
7752 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
7753 * to a function which identifies what group(along with sched group) a CPU
7754 * belongs to. The return value of group_fn must be a >= 0 and < nr_cpu_ids
7755 * (due to the fact that we keep track of groups covered with a struct cpumask).
7757 * init_sched_build_groups will build a circular linked list of the groups
7758 * covered by the given span, and will set each group's ->cpumask correctly,
7759 * and ->cpu_power to 0.
7762 init_sched_build_groups(const struct cpumask
*span
,
7763 const struct cpumask
*cpu_map
,
7764 int (*group_fn
)(int cpu
, const struct cpumask
*cpu_map
,
7765 struct sched_group
**sg
,
7766 struct cpumask
*tmpmask
),
7767 struct cpumask
*covered
, struct cpumask
*tmpmask
)
7769 struct sched_group
*first
= NULL
, *last
= NULL
;
7772 cpumask_clear(covered
);
7774 for_each_cpu(i
, span
) {
7775 struct sched_group
*sg
;
7776 int group
= group_fn(i
, cpu_map
, &sg
, tmpmask
);
7779 if (cpumask_test_cpu(i
, covered
))
7782 cpumask_clear(sched_group_cpus(sg
));
7783 sg
->__cpu_power
= 0;
7785 for_each_cpu(j
, span
) {
7786 if (group_fn(j
, cpu_map
, NULL
, tmpmask
) != group
)
7789 cpumask_set_cpu(j
, covered
);
7790 cpumask_set_cpu(j
, sched_group_cpus(sg
));
7801 #define SD_NODES_PER_DOMAIN 16
7806 * find_next_best_node - find the next node to include in a sched_domain
7807 * @node: node whose sched_domain we're building
7808 * @used_nodes: nodes already in the sched_domain
7810 * Find the next node to include in a given scheduling domain. Simply
7811 * finds the closest node not already in the @used_nodes map.
7813 * Should use nodemask_t.
7815 static int find_next_best_node(int node
, nodemask_t
*used_nodes
)
7817 int i
, n
, val
, min_val
, best_node
= 0;
7821 for (i
= 0; i
< nr_node_ids
; i
++) {
7822 /* Start at @node */
7823 n
= (node
+ i
) % nr_node_ids
;
7825 if (!nr_cpus_node(n
))
7828 /* Skip already used nodes */
7829 if (node_isset(n
, *used_nodes
))
7832 /* Simple min distance search */
7833 val
= node_distance(node
, n
);
7835 if (val
< min_val
) {
7841 node_set(best_node
, *used_nodes
);
7846 * sched_domain_node_span - get a cpumask for a node's sched_domain
7847 * @node: node whose cpumask we're constructing
7848 * @span: resulting cpumask
7850 * Given a node, construct a good cpumask for its sched_domain to span. It
7851 * should be one that prevents unnecessary balancing, but also spreads tasks
7854 static void sched_domain_node_span(int node
, struct cpumask
*span
)
7856 nodemask_t used_nodes
;
7859 cpumask_clear(span
);
7860 nodes_clear(used_nodes
);
7862 cpumask_or(span
, span
, cpumask_of_node(node
));
7863 node_set(node
, used_nodes
);
7865 for (i
= 1; i
< SD_NODES_PER_DOMAIN
; i
++) {
7866 int next_node
= find_next_best_node(node
, &used_nodes
);
7868 cpumask_or(span
, span
, cpumask_of_node(next_node
));
7871 #endif /* CONFIG_NUMA */
7873 int sched_smt_power_savings
= 0, sched_mc_power_savings
= 0;
7876 * The cpus mask in sched_group and sched_domain hangs off the end.
7877 * FIXME: use cpumask_var_t or dynamic percpu alloc to avoid wasting space
7878 * for nr_cpu_ids < CONFIG_NR_CPUS.
7880 struct static_sched_group
{
7881 struct sched_group sg
;
7882 DECLARE_BITMAP(cpus
, CONFIG_NR_CPUS
);
7885 struct static_sched_domain
{
7886 struct sched_domain sd
;
7887 DECLARE_BITMAP(span
, CONFIG_NR_CPUS
);
7891 * SMT sched-domains:
7893 #ifdef CONFIG_SCHED_SMT
7894 static DEFINE_PER_CPU(struct static_sched_domain
, cpu_domains
);
7895 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_cpus
);
7898 cpu_to_cpu_group(int cpu
, const struct cpumask
*cpu_map
,
7899 struct sched_group
**sg
, struct cpumask
*unused
)
7902 *sg
= &per_cpu(sched_group_cpus
, cpu
).sg
;
7905 #endif /* CONFIG_SCHED_SMT */
7908 * multi-core sched-domains:
7910 #ifdef CONFIG_SCHED_MC
7911 static DEFINE_PER_CPU(struct static_sched_domain
, core_domains
);
7912 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_core
);
7913 #endif /* CONFIG_SCHED_MC */
7915 #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
7917 cpu_to_core_group(int cpu
, const struct cpumask
*cpu_map
,
7918 struct sched_group
**sg
, struct cpumask
*mask
)
7922 cpumask_and(mask
, topology_thread_cpumask(cpu
), cpu_map
);
7923 group
= cpumask_first(mask
);
7925 *sg
= &per_cpu(sched_group_core
, group
).sg
;
7928 #elif defined(CONFIG_SCHED_MC)
7930 cpu_to_core_group(int cpu
, const struct cpumask
*cpu_map
,
7931 struct sched_group
**sg
, struct cpumask
*unused
)
7934 *sg
= &per_cpu(sched_group_core
, cpu
).sg
;
7939 static DEFINE_PER_CPU(struct static_sched_domain
, phys_domains
);
7940 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_phys
);
7943 cpu_to_phys_group(int cpu
, const struct cpumask
*cpu_map
,
7944 struct sched_group
**sg
, struct cpumask
*mask
)
7947 #ifdef CONFIG_SCHED_MC
7948 cpumask_and(mask
, cpu_coregroup_mask(cpu
), cpu_map
);
7949 group
= cpumask_first(mask
);
7950 #elif defined(CONFIG_SCHED_SMT)
7951 cpumask_and(mask
, topology_thread_cpumask(cpu
), cpu_map
);
7952 group
= cpumask_first(mask
);
7957 *sg
= &per_cpu(sched_group_phys
, group
).sg
;
7963 * The init_sched_build_groups can't handle what we want to do with node
7964 * groups, so roll our own. Now each node has its own list of groups which
7965 * gets dynamically allocated.
7967 static DEFINE_PER_CPU(struct static_sched_domain
, node_domains
);
7968 static struct sched_group
***sched_group_nodes_bycpu
;
7970 static DEFINE_PER_CPU(struct static_sched_domain
, allnodes_domains
);
7971 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_allnodes
);
7973 static int cpu_to_allnodes_group(int cpu
, const struct cpumask
*cpu_map
,
7974 struct sched_group
**sg
,
7975 struct cpumask
*nodemask
)
7979 cpumask_and(nodemask
, cpumask_of_node(cpu_to_node(cpu
)), cpu_map
);
7980 group
= cpumask_first(nodemask
);
7983 *sg
= &per_cpu(sched_group_allnodes
, group
).sg
;
7987 static void init_numa_sched_groups_power(struct sched_group
*group_head
)
7989 struct sched_group
*sg
= group_head
;
7995 for_each_cpu(j
, sched_group_cpus(sg
)) {
7996 struct sched_domain
*sd
;
7998 sd
= &per_cpu(phys_domains
, j
).sd
;
7999 if (j
!= group_first_cpu(sd
->groups
)) {
8001 * Only add "power" once for each
8007 sg_inc_cpu_power(sg
, sd
->groups
->__cpu_power
);
8010 } while (sg
!= group_head
);
8012 #endif /* CONFIG_NUMA */
8015 /* Free memory allocated for various sched_group structures */
8016 static void free_sched_groups(const struct cpumask
*cpu_map
,
8017 struct cpumask
*nodemask
)
8021 for_each_cpu(cpu
, cpu_map
) {
8022 struct sched_group
**sched_group_nodes
8023 = sched_group_nodes_bycpu
[cpu
];
8025 if (!sched_group_nodes
)
8028 for (i
= 0; i
< nr_node_ids
; i
++) {
8029 struct sched_group
*oldsg
, *sg
= sched_group_nodes
[i
];
8031 cpumask_and(nodemask
, cpumask_of_node(i
), cpu_map
);
8032 if (cpumask_empty(nodemask
))
8042 if (oldsg
!= sched_group_nodes
[i
])
8045 kfree(sched_group_nodes
);
8046 sched_group_nodes_bycpu
[cpu
] = NULL
;
8049 #else /* !CONFIG_NUMA */
8050 static void free_sched_groups(const struct cpumask
*cpu_map
,
8051 struct cpumask
*nodemask
)
8054 #endif /* CONFIG_NUMA */
8057 * Initialize sched groups cpu_power.
8059 * cpu_power indicates the capacity of sched group, which is used while
8060 * distributing the load between different sched groups in a sched domain.
8061 * Typically cpu_power for all the groups in a sched domain will be same unless
8062 * there are asymmetries in the topology. If there are asymmetries, group
8063 * having more cpu_power will pickup more load compared to the group having
8066 * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents
8067 * the maximum number of tasks a group can handle in the presence of other idle
8068 * or lightly loaded groups in the same sched domain.
8070 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
8072 struct sched_domain
*child
;
8073 struct sched_group
*group
;
8075 WARN_ON(!sd
|| !sd
->groups
);
8077 if (cpu
!= group_first_cpu(sd
->groups
))
8082 sd
->groups
->__cpu_power
= 0;
8085 * For perf policy, if the groups in child domain share resources
8086 * (for example cores sharing some portions of the cache hierarchy
8087 * or SMT), then set this domain groups cpu_power such that each group
8088 * can handle only one task, when there are other idle groups in the
8089 * same sched domain.
8091 if (!child
|| (!(sd
->flags
& SD_POWERSAVINGS_BALANCE
) &&
8093 (SD_SHARE_CPUPOWER
| SD_SHARE_PKG_RESOURCES
)))) {
8094 sg_inc_cpu_power(sd
->groups
, SCHED_LOAD_SCALE
);
8099 * add cpu_power of each child group to this groups cpu_power
8101 group
= child
->groups
;
8103 sg_inc_cpu_power(sd
->groups
, group
->__cpu_power
);
8104 group
= group
->next
;
8105 } while (group
!= child
->groups
);
8109 * Initializers for schedule domains
8110 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
8113 #ifdef CONFIG_SCHED_DEBUG
8114 # define SD_INIT_NAME(sd, type) sd->name = #type
8116 # define SD_INIT_NAME(sd, type) do { } while (0)
8119 #define SD_INIT(sd, type) sd_init_##type(sd)
8121 #define SD_INIT_FUNC(type) \
8122 static noinline void sd_init_##type(struct sched_domain *sd) \
8124 memset(sd, 0, sizeof(*sd)); \
8125 *sd = SD_##type##_INIT; \
8126 sd->level = SD_LV_##type; \
8127 SD_INIT_NAME(sd, type); \
8132 SD_INIT_FUNC(ALLNODES
)
8135 #ifdef CONFIG_SCHED_SMT
8136 SD_INIT_FUNC(SIBLING
)
8138 #ifdef CONFIG_SCHED_MC
8142 static int default_relax_domain_level
= -1;
8144 static int __init
setup_relax_domain_level(char *str
)
8148 val
= simple_strtoul(str
, NULL
, 0);
8149 if (val
< SD_LV_MAX
)
8150 default_relax_domain_level
= val
;
8154 __setup("relax_domain_level=", setup_relax_domain_level
);
8156 static void set_domain_attribute(struct sched_domain
*sd
,
8157 struct sched_domain_attr
*attr
)
8161 if (!attr
|| attr
->relax_domain_level
< 0) {
8162 if (default_relax_domain_level
< 0)
8165 request
= default_relax_domain_level
;
8167 request
= attr
->relax_domain_level
;
8168 if (request
< sd
->level
) {
8169 /* turn off idle balance on this domain */
8170 sd
->flags
&= ~(SD_WAKE_IDLE
|SD_BALANCE_NEWIDLE
);
8172 /* turn on idle balance on this domain */
8173 sd
->flags
|= (SD_WAKE_IDLE_FAR
|SD_BALANCE_NEWIDLE
);
8178 * Build sched domains for a given set of cpus and attach the sched domains
8179 * to the individual cpus
8181 static int __build_sched_domains(const struct cpumask
*cpu_map
,
8182 struct sched_domain_attr
*attr
)
8184 int i
, err
= -ENOMEM
;
8185 struct root_domain
*rd
;
8186 cpumask_var_t nodemask
, this_sibling_map
, this_core_map
, send_covered
,
8189 cpumask_var_t domainspan
, covered
, notcovered
;
8190 struct sched_group
**sched_group_nodes
= NULL
;
8191 int sd_allnodes
= 0;
8193 if (!alloc_cpumask_var(&domainspan
, GFP_KERNEL
))
8195 if (!alloc_cpumask_var(&covered
, GFP_KERNEL
))
8196 goto free_domainspan
;
8197 if (!alloc_cpumask_var(¬covered
, GFP_KERNEL
))
8201 if (!alloc_cpumask_var(&nodemask
, GFP_KERNEL
))
8202 goto free_notcovered
;
8203 if (!alloc_cpumask_var(&this_sibling_map
, GFP_KERNEL
))
8205 if (!alloc_cpumask_var(&this_core_map
, GFP_KERNEL
))
8206 goto free_this_sibling_map
;
8207 if (!alloc_cpumask_var(&send_covered
, GFP_KERNEL
))
8208 goto free_this_core_map
;
8209 if (!alloc_cpumask_var(&tmpmask
, GFP_KERNEL
))
8210 goto free_send_covered
;
8214 * Allocate the per-node list of sched groups
8216 sched_group_nodes
= kcalloc(nr_node_ids
, sizeof(struct sched_group
*),
8218 if (!sched_group_nodes
) {
8219 printk(KERN_WARNING
"Can not alloc sched group node list\n");
8224 rd
= alloc_rootdomain();
8226 printk(KERN_WARNING
"Cannot alloc root domain\n");
8227 goto free_sched_groups
;
8231 sched_group_nodes_bycpu
[cpumask_first(cpu_map
)] = sched_group_nodes
;
8235 * Set up domains for cpus specified by the cpu_map.
8237 for_each_cpu(i
, cpu_map
) {
8238 struct sched_domain
*sd
= NULL
, *p
;
8240 cpumask_and(nodemask
, cpumask_of_node(cpu_to_node(i
)), cpu_map
);
8243 if (cpumask_weight(cpu_map
) >
8244 SD_NODES_PER_DOMAIN
*cpumask_weight(nodemask
)) {
8245 sd
= &per_cpu(allnodes_domains
, i
).sd
;
8246 SD_INIT(sd
, ALLNODES
);
8247 set_domain_attribute(sd
, attr
);
8248 cpumask_copy(sched_domain_span(sd
), cpu_map
);
8249 cpu_to_allnodes_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
8255 sd
= &per_cpu(node_domains
, i
).sd
;
8257 set_domain_attribute(sd
, attr
);
8258 sched_domain_node_span(cpu_to_node(i
), sched_domain_span(sd
));
8262 cpumask_and(sched_domain_span(sd
),
8263 sched_domain_span(sd
), cpu_map
);
8267 sd
= &per_cpu(phys_domains
, i
).sd
;
8269 set_domain_attribute(sd
, attr
);
8270 cpumask_copy(sched_domain_span(sd
), nodemask
);
8274 cpu_to_phys_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
8276 #ifdef CONFIG_SCHED_MC
8278 sd
= &per_cpu(core_domains
, i
).sd
;
8280 set_domain_attribute(sd
, attr
);
8281 cpumask_and(sched_domain_span(sd
), cpu_map
,
8282 cpu_coregroup_mask(i
));
8285 cpu_to_core_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
8288 #ifdef CONFIG_SCHED_SMT
8290 sd
= &per_cpu(cpu_domains
, i
).sd
;
8291 SD_INIT(sd
, SIBLING
);
8292 set_domain_attribute(sd
, attr
);
8293 cpumask_and(sched_domain_span(sd
),
8294 topology_thread_cpumask(i
), cpu_map
);
8297 cpu_to_cpu_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
8301 #ifdef CONFIG_SCHED_SMT
8302 /* Set up CPU (sibling) groups */
8303 for_each_cpu(i
, cpu_map
) {
8304 cpumask_and(this_sibling_map
,
8305 topology_thread_cpumask(i
), cpu_map
);
8306 if (i
!= cpumask_first(this_sibling_map
))
8309 init_sched_build_groups(this_sibling_map
, cpu_map
,
8311 send_covered
, tmpmask
);
8315 #ifdef CONFIG_SCHED_MC
8316 /* Set up multi-core groups */
8317 for_each_cpu(i
, cpu_map
) {
8318 cpumask_and(this_core_map
, cpu_coregroup_mask(i
), cpu_map
);
8319 if (i
!= cpumask_first(this_core_map
))
8322 init_sched_build_groups(this_core_map
, cpu_map
,
8324 send_covered
, tmpmask
);
8328 /* Set up physical groups */
8329 for (i
= 0; i
< nr_node_ids
; i
++) {
8330 cpumask_and(nodemask
, cpumask_of_node(i
), cpu_map
);
8331 if (cpumask_empty(nodemask
))
8334 init_sched_build_groups(nodemask
, cpu_map
,
8336 send_covered
, tmpmask
);
8340 /* Set up node groups */
8342 init_sched_build_groups(cpu_map
, cpu_map
,
8343 &cpu_to_allnodes_group
,
8344 send_covered
, tmpmask
);
8347 for (i
= 0; i
< nr_node_ids
; i
++) {
8348 /* Set up node groups */
8349 struct sched_group
*sg
, *prev
;
8352 cpumask_clear(covered
);
8353 cpumask_and(nodemask
, cpumask_of_node(i
), cpu_map
);
8354 if (cpumask_empty(nodemask
)) {
8355 sched_group_nodes
[i
] = NULL
;
8359 sched_domain_node_span(i
, domainspan
);
8360 cpumask_and(domainspan
, domainspan
, cpu_map
);
8362 sg
= kmalloc_node(sizeof(struct sched_group
) + cpumask_size(),
8365 printk(KERN_WARNING
"Can not alloc domain group for "
8369 sched_group_nodes
[i
] = sg
;
8370 for_each_cpu(j
, nodemask
) {
8371 struct sched_domain
*sd
;
8373 sd
= &per_cpu(node_domains
, j
).sd
;
8376 sg
->__cpu_power
= 0;
8377 cpumask_copy(sched_group_cpus(sg
), nodemask
);
8379 cpumask_or(covered
, covered
, nodemask
);
8382 for (j
= 0; j
< nr_node_ids
; j
++) {
8383 int n
= (i
+ j
) % nr_node_ids
;
8385 cpumask_complement(notcovered
, covered
);
8386 cpumask_and(tmpmask
, notcovered
, cpu_map
);
8387 cpumask_and(tmpmask
, tmpmask
, domainspan
);
8388 if (cpumask_empty(tmpmask
))
8391 cpumask_and(tmpmask
, tmpmask
, cpumask_of_node(n
));
8392 if (cpumask_empty(tmpmask
))
8395 sg
= kmalloc_node(sizeof(struct sched_group
) +
8400 "Can not alloc domain group for node %d\n", j
);
8403 sg
->__cpu_power
= 0;
8404 cpumask_copy(sched_group_cpus(sg
), tmpmask
);
8405 sg
->next
= prev
->next
;
8406 cpumask_or(covered
, covered
, tmpmask
);
8413 /* Calculate CPU power for physical packages and nodes */
8414 #ifdef CONFIG_SCHED_SMT
8415 for_each_cpu(i
, cpu_map
) {
8416 struct sched_domain
*sd
= &per_cpu(cpu_domains
, i
).sd
;
8418 init_sched_groups_power(i
, sd
);
8421 #ifdef CONFIG_SCHED_MC
8422 for_each_cpu(i
, cpu_map
) {
8423 struct sched_domain
*sd
= &per_cpu(core_domains
, i
).sd
;
8425 init_sched_groups_power(i
, sd
);
8429 for_each_cpu(i
, cpu_map
) {
8430 struct sched_domain
*sd
= &per_cpu(phys_domains
, i
).sd
;
8432 init_sched_groups_power(i
, sd
);
8436 for (i
= 0; i
< nr_node_ids
; i
++)
8437 init_numa_sched_groups_power(sched_group_nodes
[i
]);
8440 struct sched_group
*sg
;
8442 cpu_to_allnodes_group(cpumask_first(cpu_map
), cpu_map
, &sg
,
8444 init_numa_sched_groups_power(sg
);
8448 /* Attach the domains */
8449 for_each_cpu(i
, cpu_map
) {
8450 struct sched_domain
*sd
;
8451 #ifdef CONFIG_SCHED_SMT
8452 sd
= &per_cpu(cpu_domains
, i
).sd
;
8453 #elif defined(CONFIG_SCHED_MC)
8454 sd
= &per_cpu(core_domains
, i
).sd
;
8456 sd
= &per_cpu(phys_domains
, i
).sd
;
8458 cpu_attach_domain(sd
, rd
, i
);
8464 free_cpumask_var(tmpmask
);
8466 free_cpumask_var(send_covered
);
8468 free_cpumask_var(this_core_map
);
8469 free_this_sibling_map
:
8470 free_cpumask_var(this_sibling_map
);
8472 free_cpumask_var(nodemask
);
8475 free_cpumask_var(notcovered
);
8477 free_cpumask_var(covered
);
8479 free_cpumask_var(domainspan
);
8486 kfree(sched_group_nodes
);
8492 free_sched_groups(cpu_map
, tmpmask
);
8493 free_rootdomain(rd
);
8498 static int build_sched_domains(const struct cpumask
*cpu_map
)
8500 return __build_sched_domains(cpu_map
, NULL
);
8503 static struct cpumask
*doms_cur
; /* current sched domains */
8504 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
8505 static struct sched_domain_attr
*dattr_cur
;
8506 /* attribues of custom domains in 'doms_cur' */
8509 * Special case: If a kmalloc of a doms_cur partition (array of
8510 * cpumask) fails, then fallback to a single sched domain,
8511 * as determined by the single cpumask fallback_doms.
8513 static cpumask_var_t fallback_doms
;
8516 * arch_update_cpu_topology lets virtualized architectures update the
8517 * cpu core maps. It is supposed to return 1 if the topology changed
8518 * or 0 if it stayed the same.
8520 int __attribute__((weak
)) arch_update_cpu_topology(void)
8526 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
8527 * For now this just excludes isolated cpus, but could be used to
8528 * exclude other special cases in the future.
8530 static int arch_init_sched_domains(const struct cpumask
*cpu_map
)
8534 arch_update_cpu_topology();
8536 doms_cur
= kmalloc(cpumask_size(), GFP_KERNEL
);
8538 doms_cur
= fallback_doms
;
8539 cpumask_andnot(doms_cur
, cpu_map
, cpu_isolated_map
);
8541 err
= build_sched_domains(doms_cur
);
8542 register_sched_domain_sysctl();
8547 static void arch_destroy_sched_domains(const struct cpumask
*cpu_map
,
8548 struct cpumask
*tmpmask
)
8550 free_sched_groups(cpu_map
, tmpmask
);
8554 * Detach sched domains from a group of cpus specified in cpu_map
8555 * These cpus will now be attached to the NULL domain
8557 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
8559 /* Save because hotplug lock held. */
8560 static DECLARE_BITMAP(tmpmask
, CONFIG_NR_CPUS
);
8563 for_each_cpu(i
, cpu_map
)
8564 cpu_attach_domain(NULL
, &def_root_domain
, i
);
8565 synchronize_sched();
8566 arch_destroy_sched_domains(cpu_map
, to_cpumask(tmpmask
));
8569 /* handle null as "default" */
8570 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
8571 struct sched_domain_attr
*new, int idx_new
)
8573 struct sched_domain_attr tmp
;
8580 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
8581 new ? (new + idx_new
) : &tmp
,
8582 sizeof(struct sched_domain_attr
));
8586 * Partition sched domains as specified by the 'ndoms_new'
8587 * cpumasks in the array doms_new[] of cpumasks. This compares
8588 * doms_new[] to the current sched domain partitioning, doms_cur[].
8589 * It destroys each deleted domain and builds each new domain.
8591 * 'doms_new' is an array of cpumask's of length 'ndoms_new'.
8592 * The masks don't intersect (don't overlap.) We should setup one
8593 * sched domain for each mask. CPUs not in any of the cpumasks will
8594 * not be load balanced. If the same cpumask appears both in the
8595 * current 'doms_cur' domains and in the new 'doms_new', we can leave
8598 * The passed in 'doms_new' should be kmalloc'd. This routine takes
8599 * ownership of it and will kfree it when done with it. If the caller
8600 * failed the kmalloc call, then it can pass in doms_new == NULL &&
8601 * ndoms_new == 1, and partition_sched_domains() will fallback to
8602 * the single partition 'fallback_doms', it also forces the domains
8605 * If doms_new == NULL it will be replaced with cpu_online_mask.
8606 * ndoms_new == 0 is a special case for destroying existing domains,
8607 * and it will not create the default domain.
8609 * Call with hotplug lock held
8611 /* FIXME: Change to struct cpumask *doms_new[] */
8612 void partition_sched_domains(int ndoms_new
, struct cpumask
*doms_new
,
8613 struct sched_domain_attr
*dattr_new
)
8618 mutex_lock(&sched_domains_mutex
);
8620 /* always unregister in case we don't destroy any domains */
8621 unregister_sched_domain_sysctl();
8623 /* Let architecture update cpu core mappings. */
8624 new_topology
= arch_update_cpu_topology();
8626 n
= doms_new
? ndoms_new
: 0;
8628 /* Destroy deleted domains */
8629 for (i
= 0; i
< ndoms_cur
; i
++) {
8630 for (j
= 0; j
< n
&& !new_topology
; j
++) {
8631 if (cpumask_equal(&doms_cur
[i
], &doms_new
[j
])
8632 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
8635 /* no match - a current sched domain not in new doms_new[] */
8636 detach_destroy_domains(doms_cur
+ i
);
8641 if (doms_new
== NULL
) {
8643 doms_new
= fallback_doms
;
8644 cpumask_andnot(&doms_new
[0], cpu_online_mask
, cpu_isolated_map
);
8645 WARN_ON_ONCE(dattr_new
);
8648 /* Build new domains */
8649 for (i
= 0; i
< ndoms_new
; i
++) {
8650 for (j
= 0; j
< ndoms_cur
&& !new_topology
; j
++) {
8651 if (cpumask_equal(&doms_new
[i
], &doms_cur
[j
])
8652 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
8655 /* no match - add a new doms_new */
8656 __build_sched_domains(doms_new
+ i
,
8657 dattr_new
? dattr_new
+ i
: NULL
);
8662 /* Remember the new sched domains */
8663 if (doms_cur
!= fallback_doms
)
8665 kfree(dattr_cur
); /* kfree(NULL) is safe */
8666 doms_cur
= doms_new
;
8667 dattr_cur
= dattr_new
;
8668 ndoms_cur
= ndoms_new
;
8670 register_sched_domain_sysctl();
8672 mutex_unlock(&sched_domains_mutex
);
8675 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
8676 static void arch_reinit_sched_domains(void)
8680 /* Destroy domains first to force the rebuild */
8681 partition_sched_domains(0, NULL
, NULL
);
8683 rebuild_sched_domains();
8687 static ssize_t
sched_power_savings_store(const char *buf
, size_t count
, int smt
)
8689 unsigned int level
= 0;
8691 if (sscanf(buf
, "%u", &level
) != 1)
8695 * level is always be positive so don't check for
8696 * level < POWERSAVINGS_BALANCE_NONE which is 0
8697 * What happens on 0 or 1 byte write,
8698 * need to check for count as well?
8701 if (level
>= MAX_POWERSAVINGS_BALANCE_LEVELS
)
8705 sched_smt_power_savings
= level
;
8707 sched_mc_power_savings
= level
;
8709 arch_reinit_sched_domains();
8714 #ifdef CONFIG_SCHED_MC
8715 static ssize_t
sched_mc_power_savings_show(struct sysdev_class
*class,
8718 return sprintf(page
, "%u\n", sched_mc_power_savings
);
8720 static ssize_t
sched_mc_power_savings_store(struct sysdev_class
*class,
8721 const char *buf
, size_t count
)
8723 return sched_power_savings_store(buf
, count
, 0);
8725 static SYSDEV_CLASS_ATTR(sched_mc_power_savings
, 0644,
8726 sched_mc_power_savings_show
,
8727 sched_mc_power_savings_store
);
8730 #ifdef CONFIG_SCHED_SMT
8731 static ssize_t
sched_smt_power_savings_show(struct sysdev_class
*dev
,
8734 return sprintf(page
, "%u\n", sched_smt_power_savings
);
8736 static ssize_t
sched_smt_power_savings_store(struct sysdev_class
*dev
,
8737 const char *buf
, size_t count
)
8739 return sched_power_savings_store(buf
, count
, 1);
8741 static SYSDEV_CLASS_ATTR(sched_smt_power_savings
, 0644,
8742 sched_smt_power_savings_show
,
8743 sched_smt_power_savings_store
);
8746 int __init
sched_create_sysfs_power_savings_entries(struct sysdev_class
*cls
)
8750 #ifdef CONFIG_SCHED_SMT
8752 err
= sysfs_create_file(&cls
->kset
.kobj
,
8753 &attr_sched_smt_power_savings
.attr
);
8755 #ifdef CONFIG_SCHED_MC
8756 if (!err
&& mc_capable())
8757 err
= sysfs_create_file(&cls
->kset
.kobj
,
8758 &attr_sched_mc_power_savings
.attr
);
8762 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
8764 #ifndef CONFIG_CPUSETS
8766 * Add online and remove offline CPUs from the scheduler domains.
8767 * When cpusets are enabled they take over this function.
8769 static int update_sched_domains(struct notifier_block
*nfb
,
8770 unsigned long action
, void *hcpu
)
8774 case CPU_ONLINE_FROZEN
:
8776 case CPU_DEAD_FROZEN
:
8777 partition_sched_domains(1, NULL
, NULL
);
8786 static int update_runtime(struct notifier_block
*nfb
,
8787 unsigned long action
, void *hcpu
)
8789 int cpu
= (int)(long)hcpu
;
8792 case CPU_DOWN_PREPARE
:
8793 case CPU_DOWN_PREPARE_FROZEN
:
8794 disable_runtime(cpu_rq(cpu
));
8797 case CPU_DOWN_FAILED
:
8798 case CPU_DOWN_FAILED_FROZEN
:
8800 case CPU_ONLINE_FROZEN
:
8801 enable_runtime(cpu_rq(cpu
));
8809 void __init
sched_init_smp(void)
8811 cpumask_var_t non_isolated_cpus
;
8813 alloc_cpumask_var(&non_isolated_cpus
, GFP_KERNEL
);
8815 #if defined(CONFIG_NUMA)
8816 sched_group_nodes_bycpu
= kzalloc(nr_cpu_ids
* sizeof(void **),
8818 BUG_ON(sched_group_nodes_bycpu
== NULL
);
8821 mutex_lock(&sched_domains_mutex
);
8822 arch_init_sched_domains(cpu_online_mask
);
8823 cpumask_andnot(non_isolated_cpus
, cpu_possible_mask
, cpu_isolated_map
);
8824 if (cpumask_empty(non_isolated_cpus
))
8825 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus
);
8826 mutex_unlock(&sched_domains_mutex
);
8829 #ifndef CONFIG_CPUSETS
8830 /* XXX: Theoretical race here - CPU may be hotplugged now */
8831 hotcpu_notifier(update_sched_domains
, 0);
8834 /* RT runtime code needs to handle some hotplug events */
8835 hotcpu_notifier(update_runtime
, 0);
8839 /* Move init over to a non-isolated CPU */
8840 if (set_cpus_allowed_ptr(current
, non_isolated_cpus
) < 0)
8842 sched_init_granularity();
8843 free_cpumask_var(non_isolated_cpus
);
8845 alloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
8846 init_sched_rt_class();
8849 void __init
sched_init_smp(void)
8851 sched_init_granularity();
8853 #endif /* CONFIG_SMP */
8855 int in_sched_functions(unsigned long addr
)
8857 return in_lock_functions(addr
) ||
8858 (addr
>= (unsigned long)__sched_text_start
8859 && addr
< (unsigned long)__sched_text_end
);
8862 static void init_cfs_rq(struct cfs_rq
*cfs_rq
, struct rq
*rq
)
8864 cfs_rq
->tasks_timeline
= RB_ROOT
;
8865 INIT_LIST_HEAD(&cfs_rq
->tasks
);
8866 #ifdef CONFIG_FAIR_GROUP_SCHED
8869 cfs_rq
->min_vruntime
= (u64
)(-(1LL << 20));
8872 static void init_rt_rq(struct rt_rq
*rt_rq
, struct rq
*rq
)
8874 struct rt_prio_array
*array
;
8877 array
= &rt_rq
->active
;
8878 for (i
= 0; i
< MAX_RT_PRIO
; i
++) {
8879 INIT_LIST_HEAD(array
->queue
+ i
);
8880 __clear_bit(i
, array
->bitmap
);
8882 /* delimiter for bitsearch: */
8883 __set_bit(MAX_RT_PRIO
, array
->bitmap
);
8885 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
8886 rt_rq
->highest_prio
.curr
= MAX_RT_PRIO
;
8888 rt_rq
->highest_prio
.next
= MAX_RT_PRIO
;
8892 rt_rq
->rt_nr_migratory
= 0;
8893 rt_rq
->overloaded
= 0;
8894 plist_head_init(&rq
->rt
.pushable_tasks
, &rq
->lock
);
8898 rt_rq
->rt_throttled
= 0;
8899 rt_rq
->rt_runtime
= 0;
8900 spin_lock_init(&rt_rq
->rt_runtime_lock
);
8902 #ifdef CONFIG_RT_GROUP_SCHED
8903 rt_rq
->rt_nr_boosted
= 0;
8908 #ifdef CONFIG_FAIR_GROUP_SCHED
8909 static void init_tg_cfs_entry(struct task_group
*tg
, struct cfs_rq
*cfs_rq
,
8910 struct sched_entity
*se
, int cpu
, int add
,
8911 struct sched_entity
*parent
)
8913 struct rq
*rq
= cpu_rq(cpu
);
8914 tg
->cfs_rq
[cpu
] = cfs_rq
;
8915 init_cfs_rq(cfs_rq
, rq
);
8918 list_add(&cfs_rq
->leaf_cfs_rq_list
, &rq
->leaf_cfs_rq_list
);
8921 /* se could be NULL for init_task_group */
8926 se
->cfs_rq
= &rq
->cfs
;
8928 se
->cfs_rq
= parent
->my_q
;
8931 se
->load
.weight
= tg
->shares
;
8932 se
->load
.inv_weight
= 0;
8933 se
->parent
= parent
;
8937 #ifdef CONFIG_RT_GROUP_SCHED
8938 static void init_tg_rt_entry(struct task_group
*tg
, struct rt_rq
*rt_rq
,
8939 struct sched_rt_entity
*rt_se
, int cpu
, int add
,
8940 struct sched_rt_entity
*parent
)
8942 struct rq
*rq
= cpu_rq(cpu
);
8944 tg
->rt_rq
[cpu
] = rt_rq
;
8945 init_rt_rq(rt_rq
, rq
);
8947 rt_rq
->rt_se
= rt_se
;
8948 rt_rq
->rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
8950 list_add(&rt_rq
->leaf_rt_rq_list
, &rq
->leaf_rt_rq_list
);
8952 tg
->rt_se
[cpu
] = rt_se
;
8957 rt_se
->rt_rq
= &rq
->rt
;
8959 rt_se
->rt_rq
= parent
->my_q
;
8961 rt_se
->my_q
= rt_rq
;
8962 rt_se
->parent
= parent
;
8963 INIT_LIST_HEAD(&rt_se
->run_list
);
8967 void __init
sched_init(void)
8970 unsigned long alloc_size
= 0, ptr
;
8972 #ifdef CONFIG_FAIR_GROUP_SCHED
8973 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
8975 #ifdef CONFIG_RT_GROUP_SCHED
8976 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
8978 #ifdef CONFIG_USER_SCHED
8981 #ifdef CONFIG_CPUMASK_OFFSTACK
8982 alloc_size
+= num_possible_cpus() * cpumask_size();
8985 * As sched_init() is called before page_alloc is setup,
8986 * we use alloc_bootmem().
8989 ptr
= (unsigned long)alloc_bootmem(alloc_size
);
8991 #ifdef CONFIG_FAIR_GROUP_SCHED
8992 init_task_group
.se
= (struct sched_entity
**)ptr
;
8993 ptr
+= nr_cpu_ids
* sizeof(void **);
8995 init_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
8996 ptr
+= nr_cpu_ids
* sizeof(void **);
8998 #ifdef CONFIG_USER_SCHED
8999 root_task_group
.se
= (struct sched_entity
**)ptr
;
9000 ptr
+= nr_cpu_ids
* sizeof(void **);
9002 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
9003 ptr
+= nr_cpu_ids
* sizeof(void **);
9004 #endif /* CONFIG_USER_SCHED */
9005 #endif /* CONFIG_FAIR_GROUP_SCHED */
9006 #ifdef CONFIG_RT_GROUP_SCHED
9007 init_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
9008 ptr
+= nr_cpu_ids
* sizeof(void **);
9010 init_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
9011 ptr
+= nr_cpu_ids
* sizeof(void **);
9013 #ifdef CONFIG_USER_SCHED
9014 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
9015 ptr
+= nr_cpu_ids
* sizeof(void **);
9017 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
9018 ptr
+= nr_cpu_ids
* sizeof(void **);
9019 #endif /* CONFIG_USER_SCHED */
9020 #endif /* CONFIG_RT_GROUP_SCHED */
9021 #ifdef CONFIG_CPUMASK_OFFSTACK
9022 for_each_possible_cpu(i
) {
9023 per_cpu(load_balance_tmpmask
, i
) = (void *)ptr
;
9024 ptr
+= cpumask_size();
9026 #endif /* CONFIG_CPUMASK_OFFSTACK */
9030 init_defrootdomain();
9033 init_rt_bandwidth(&def_rt_bandwidth
,
9034 global_rt_period(), global_rt_runtime());
9036 #ifdef CONFIG_RT_GROUP_SCHED
9037 init_rt_bandwidth(&init_task_group
.rt_bandwidth
,
9038 global_rt_period(), global_rt_runtime());
9039 #ifdef CONFIG_USER_SCHED
9040 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
9041 global_rt_period(), RUNTIME_INF
);
9042 #endif /* CONFIG_USER_SCHED */
9043 #endif /* CONFIG_RT_GROUP_SCHED */
9045 #ifdef CONFIG_GROUP_SCHED
9046 list_add(&init_task_group
.list
, &task_groups
);
9047 INIT_LIST_HEAD(&init_task_group
.children
);
9049 #ifdef CONFIG_USER_SCHED
9050 INIT_LIST_HEAD(&root_task_group
.children
);
9051 init_task_group
.parent
= &root_task_group
;
9052 list_add(&init_task_group
.siblings
, &root_task_group
.children
);
9053 #endif /* CONFIG_USER_SCHED */
9054 #endif /* CONFIG_GROUP_SCHED */
9056 for_each_possible_cpu(i
) {
9060 spin_lock_init(&rq
->lock
);
9062 init_cfs_rq(&rq
->cfs
, rq
);
9063 init_rt_rq(&rq
->rt
, rq
);
9064 #ifdef CONFIG_FAIR_GROUP_SCHED
9065 init_task_group
.shares
= init_task_group_load
;
9066 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
9067 #ifdef CONFIG_CGROUP_SCHED
9069 * How much cpu bandwidth does init_task_group get?
9071 * In case of task-groups formed thr' the cgroup filesystem, it
9072 * gets 100% of the cpu resources in the system. This overall
9073 * system cpu resource is divided among the tasks of
9074 * init_task_group and its child task-groups in a fair manner,
9075 * based on each entity's (task or task-group's) weight
9076 * (se->load.weight).
9078 * In other words, if init_task_group has 10 tasks of weight
9079 * 1024) and two child groups A0 and A1 (of weight 1024 each),
9080 * then A0's share of the cpu resource is:
9082 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
9084 * We achieve this by letting init_task_group's tasks sit
9085 * directly in rq->cfs (i.e init_task_group->se[] = NULL).
9087 init_tg_cfs_entry(&init_task_group
, &rq
->cfs
, NULL
, i
, 1, NULL
);
9088 #elif defined CONFIG_USER_SCHED
9089 root_task_group
.shares
= NICE_0_LOAD
;
9090 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, 0, NULL
);
9092 * In case of task-groups formed thr' the user id of tasks,
9093 * init_task_group represents tasks belonging to root user.
9094 * Hence it forms a sibling of all subsequent groups formed.
9095 * In this case, init_task_group gets only a fraction of overall
9096 * system cpu resource, based on the weight assigned to root
9097 * user's cpu share (INIT_TASK_GROUP_LOAD). This is accomplished
9098 * by letting tasks of init_task_group sit in a separate cfs_rq
9099 * (init_cfs_rq) and having one entity represent this group of
9100 * tasks in rq->cfs (i.e init_task_group->se[] != NULL).
9102 init_tg_cfs_entry(&init_task_group
,
9103 &per_cpu(init_cfs_rq
, i
),
9104 &per_cpu(init_sched_entity
, i
), i
, 1,
9105 root_task_group
.se
[i
]);
9108 #endif /* CONFIG_FAIR_GROUP_SCHED */
9110 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
9111 #ifdef CONFIG_RT_GROUP_SCHED
9112 INIT_LIST_HEAD(&rq
->leaf_rt_rq_list
);
9113 #ifdef CONFIG_CGROUP_SCHED
9114 init_tg_rt_entry(&init_task_group
, &rq
->rt
, NULL
, i
, 1, NULL
);
9115 #elif defined CONFIG_USER_SCHED
9116 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, 0, NULL
);
9117 init_tg_rt_entry(&init_task_group
,
9118 &per_cpu(init_rt_rq
, i
),
9119 &per_cpu(init_sched_rt_entity
, i
), i
, 1,
9120 root_task_group
.rt_se
[i
]);
9124 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
9125 rq
->cpu_load
[j
] = 0;
9129 rq
->active_balance
= 0;
9130 rq
->next_balance
= jiffies
;
9134 rq
->migration_thread
= NULL
;
9135 INIT_LIST_HEAD(&rq
->migration_queue
);
9136 rq_attach_root(rq
, &def_root_domain
);
9139 atomic_set(&rq
->nr_iowait
, 0);
9142 set_load_weight(&init_task
);
9144 #ifdef CONFIG_PREEMPT_NOTIFIERS
9145 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
9149 open_softirq(SCHED_SOFTIRQ
, run_rebalance_domains
);
9152 #ifdef CONFIG_RT_MUTEXES
9153 plist_head_init(&init_task
.pi_waiters
, &init_task
.pi_lock
);
9157 * The boot idle thread does lazy MMU switching as well:
9159 atomic_inc(&init_mm
.mm_count
);
9160 enter_lazy_tlb(&init_mm
, current
);
9163 * Make us the idle thread. Technically, schedule() should not be
9164 * called from this thread, however somewhere below it might be,
9165 * but because we are the idle thread, we just pick up running again
9166 * when this runqueue becomes "idle".
9168 init_idle(current
, smp_processor_id());
9170 * During early bootup we pretend to be a normal task:
9172 current
->sched_class
= &fair_sched_class
;
9174 /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */
9175 alloc_bootmem_cpumask_var(&nohz_cpu_mask
);
9178 alloc_bootmem_cpumask_var(&nohz
.cpu_mask
);
9179 alloc_bootmem_cpumask_var(&nohz
.ilb_grp_nohz_mask
);
9181 alloc_bootmem_cpumask_var(&cpu_isolated_map
);
9184 scheduler_running
= 1;
9187 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
9188 void __might_sleep(char *file
, int line
)
9191 static unsigned long prev_jiffy
; /* ratelimiting */
9193 if ((!in_atomic() && !irqs_disabled()) ||
9194 system_state
!= SYSTEM_RUNNING
|| oops_in_progress
)
9196 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
9198 prev_jiffy
= jiffies
;
9201 "BUG: sleeping function called from invalid context at %s:%d\n",
9204 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
9205 in_atomic(), irqs_disabled(),
9206 current
->pid
, current
->comm
);
9208 debug_show_held_locks(current
);
9209 if (irqs_disabled())
9210 print_irqtrace_events(current
);
9214 EXPORT_SYMBOL(__might_sleep
);
9217 #ifdef CONFIG_MAGIC_SYSRQ
9218 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
9222 update_rq_clock(rq
);
9223 on_rq
= p
->se
.on_rq
;
9225 deactivate_task(rq
, p
, 0);
9226 __setscheduler(rq
, p
, SCHED_NORMAL
, 0);
9228 activate_task(rq
, p
, 0);
9229 resched_task(rq
->curr
);
9233 void normalize_rt_tasks(void)
9235 struct task_struct
*g
, *p
;
9236 unsigned long flags
;
9239 read_lock_irqsave(&tasklist_lock
, flags
);
9240 do_each_thread(g
, p
) {
9242 * Only normalize user tasks:
9247 p
->se
.exec_start
= 0;
9248 #ifdef CONFIG_SCHEDSTATS
9249 p
->se
.wait_start
= 0;
9250 p
->se
.sleep_start
= 0;
9251 p
->se
.block_start
= 0;
9256 * Renice negative nice level userspace
9259 if (TASK_NICE(p
) < 0 && p
->mm
)
9260 set_user_nice(p
, 0);
9264 spin_lock(&p
->pi_lock
);
9265 rq
= __task_rq_lock(p
);
9267 normalize_task(rq
, p
);
9269 __task_rq_unlock(rq
);
9270 spin_unlock(&p
->pi_lock
);
9271 } while_each_thread(g
, p
);
9273 read_unlock_irqrestore(&tasklist_lock
, flags
);
9276 #endif /* CONFIG_MAGIC_SYSRQ */
9280 * These functions are only useful for the IA64 MCA handling.
9282 * They can only be called when the whole system has been
9283 * stopped - every CPU needs to be quiescent, and no scheduling
9284 * activity can take place. Using them for anything else would
9285 * be a serious bug, and as a result, they aren't even visible
9286 * under any other configuration.
9290 * curr_task - return the current task for a given cpu.
9291 * @cpu: the processor in question.
9293 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
9295 struct task_struct
*curr_task(int cpu
)
9297 return cpu_curr(cpu
);
9301 * set_curr_task - set the current task for a given cpu.
9302 * @cpu: the processor in question.
9303 * @p: the task pointer to set.
9305 * Description: This function must only be used when non-maskable interrupts
9306 * are serviced on a separate stack. It allows the architecture to switch the
9307 * notion of the current task on a cpu in a non-blocking manner. This function
9308 * must be called with all CPU's synchronized, and interrupts disabled, the
9309 * and caller must save the original value of the current task (see
9310 * curr_task() above) and restore that value before reenabling interrupts and
9311 * re-starting the system.
9313 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
9315 void set_curr_task(int cpu
, struct task_struct
*p
)
9322 #ifdef CONFIG_FAIR_GROUP_SCHED
9323 static void free_fair_sched_group(struct task_group
*tg
)
9327 for_each_possible_cpu(i
) {
9329 kfree(tg
->cfs_rq
[i
]);
9339 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
9341 struct cfs_rq
*cfs_rq
;
9342 struct sched_entity
*se
;
9346 tg
->cfs_rq
= kzalloc(sizeof(cfs_rq
) * nr_cpu_ids
, GFP_KERNEL
);
9349 tg
->se
= kzalloc(sizeof(se
) * nr_cpu_ids
, GFP_KERNEL
);
9353 tg
->shares
= NICE_0_LOAD
;
9355 for_each_possible_cpu(i
) {
9358 cfs_rq
= kzalloc_node(sizeof(struct cfs_rq
),
9359 GFP_KERNEL
, cpu_to_node(i
));
9363 se
= kzalloc_node(sizeof(struct sched_entity
),
9364 GFP_KERNEL
, cpu_to_node(i
));
9368 init_tg_cfs_entry(tg
, cfs_rq
, se
, i
, 0, parent
->se
[i
]);
9377 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
9379 list_add_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
,
9380 &cpu_rq(cpu
)->leaf_cfs_rq_list
);
9383 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
9385 list_del_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
);
9387 #else /* !CONFG_FAIR_GROUP_SCHED */
9388 static inline void free_fair_sched_group(struct task_group
*tg
)
9393 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
9398 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
9402 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
9405 #endif /* CONFIG_FAIR_GROUP_SCHED */
9407 #ifdef CONFIG_RT_GROUP_SCHED
9408 static void free_rt_sched_group(struct task_group
*tg
)
9412 destroy_rt_bandwidth(&tg
->rt_bandwidth
);
9414 for_each_possible_cpu(i
) {
9416 kfree(tg
->rt_rq
[i
]);
9418 kfree(tg
->rt_se
[i
]);
9426 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
9428 struct rt_rq
*rt_rq
;
9429 struct sched_rt_entity
*rt_se
;
9433 tg
->rt_rq
= kzalloc(sizeof(rt_rq
) * nr_cpu_ids
, GFP_KERNEL
);
9436 tg
->rt_se
= kzalloc(sizeof(rt_se
) * nr_cpu_ids
, GFP_KERNEL
);
9440 init_rt_bandwidth(&tg
->rt_bandwidth
,
9441 ktime_to_ns(def_rt_bandwidth
.rt_period
), 0);
9443 for_each_possible_cpu(i
) {
9446 rt_rq
= kzalloc_node(sizeof(struct rt_rq
),
9447 GFP_KERNEL
, cpu_to_node(i
));
9451 rt_se
= kzalloc_node(sizeof(struct sched_rt_entity
),
9452 GFP_KERNEL
, cpu_to_node(i
));
9456 init_tg_rt_entry(tg
, rt_rq
, rt_se
, i
, 0, parent
->rt_se
[i
]);
9465 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
9467 list_add_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
,
9468 &cpu_rq(cpu
)->leaf_rt_rq_list
);
9471 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
9473 list_del_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
);
9475 #else /* !CONFIG_RT_GROUP_SCHED */
9476 static inline void free_rt_sched_group(struct task_group
*tg
)
9481 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
9486 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
9490 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
9493 #endif /* CONFIG_RT_GROUP_SCHED */
9495 #ifdef CONFIG_GROUP_SCHED
9496 static void free_sched_group(struct task_group
*tg
)
9498 free_fair_sched_group(tg
);
9499 free_rt_sched_group(tg
);
9503 /* allocate runqueue etc for a new task group */
9504 struct task_group
*sched_create_group(struct task_group
*parent
)
9506 struct task_group
*tg
;
9507 unsigned long flags
;
9510 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
9512 return ERR_PTR(-ENOMEM
);
9514 if (!alloc_fair_sched_group(tg
, parent
))
9517 if (!alloc_rt_sched_group(tg
, parent
))
9520 spin_lock_irqsave(&task_group_lock
, flags
);
9521 for_each_possible_cpu(i
) {
9522 register_fair_sched_group(tg
, i
);
9523 register_rt_sched_group(tg
, i
);
9525 list_add_rcu(&tg
->list
, &task_groups
);
9527 WARN_ON(!parent
); /* root should already exist */
9529 tg
->parent
= parent
;
9530 INIT_LIST_HEAD(&tg
->children
);
9531 list_add_rcu(&tg
->siblings
, &parent
->children
);
9532 spin_unlock_irqrestore(&task_group_lock
, flags
);
9537 free_sched_group(tg
);
9538 return ERR_PTR(-ENOMEM
);
9541 /* rcu callback to free various structures associated with a task group */
9542 static void free_sched_group_rcu(struct rcu_head
*rhp
)
9544 /* now it should be safe to free those cfs_rqs */
9545 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
9548 /* Destroy runqueue etc associated with a task group */
9549 void sched_destroy_group(struct task_group
*tg
)
9551 unsigned long flags
;
9554 spin_lock_irqsave(&task_group_lock
, flags
);
9555 for_each_possible_cpu(i
) {
9556 unregister_fair_sched_group(tg
, i
);
9557 unregister_rt_sched_group(tg
, i
);
9559 list_del_rcu(&tg
->list
);
9560 list_del_rcu(&tg
->siblings
);
9561 spin_unlock_irqrestore(&task_group_lock
, flags
);
9563 /* wait for possible concurrent references to cfs_rqs complete */
9564 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
9567 /* change task's runqueue when it moves between groups.
9568 * The caller of this function should have put the task in its new group
9569 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
9570 * reflect its new group.
9572 void sched_move_task(struct task_struct
*tsk
)
9575 unsigned long flags
;
9578 rq
= task_rq_lock(tsk
, &flags
);
9580 update_rq_clock(rq
);
9582 running
= task_current(rq
, tsk
);
9583 on_rq
= tsk
->se
.on_rq
;
9586 dequeue_task(rq
, tsk
, 0);
9587 if (unlikely(running
))
9588 tsk
->sched_class
->put_prev_task(rq
, tsk
);
9590 set_task_rq(tsk
, task_cpu(tsk
));
9592 #ifdef CONFIG_FAIR_GROUP_SCHED
9593 if (tsk
->sched_class
->moved_group
)
9594 tsk
->sched_class
->moved_group(tsk
);
9597 if (unlikely(running
))
9598 tsk
->sched_class
->set_curr_task(rq
);
9600 enqueue_task(rq
, tsk
, 0);
9602 task_rq_unlock(rq
, &flags
);
9604 #endif /* CONFIG_GROUP_SCHED */
9606 #ifdef CONFIG_FAIR_GROUP_SCHED
9607 static void __set_se_shares(struct sched_entity
*se
, unsigned long shares
)
9609 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
9614 dequeue_entity(cfs_rq
, se
, 0);
9616 se
->load
.weight
= shares
;
9617 se
->load
.inv_weight
= 0;
9620 enqueue_entity(cfs_rq
, se
, 0);
9623 static void set_se_shares(struct sched_entity
*se
, unsigned long shares
)
9625 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
9626 struct rq
*rq
= cfs_rq
->rq
;
9627 unsigned long flags
;
9629 spin_lock_irqsave(&rq
->lock
, flags
);
9630 __set_se_shares(se
, shares
);
9631 spin_unlock_irqrestore(&rq
->lock
, flags
);
9634 static DEFINE_MUTEX(shares_mutex
);
9636 int sched_group_set_shares(struct task_group
*tg
, unsigned long shares
)
9639 unsigned long flags
;
9642 * We can't change the weight of the root cgroup.
9647 if (shares
< MIN_SHARES
)
9648 shares
= MIN_SHARES
;
9649 else if (shares
> MAX_SHARES
)
9650 shares
= MAX_SHARES
;
9652 mutex_lock(&shares_mutex
);
9653 if (tg
->shares
== shares
)
9656 spin_lock_irqsave(&task_group_lock
, flags
);
9657 for_each_possible_cpu(i
)
9658 unregister_fair_sched_group(tg
, i
);
9659 list_del_rcu(&tg
->siblings
);
9660 spin_unlock_irqrestore(&task_group_lock
, flags
);
9662 /* wait for any ongoing reference to this group to finish */
9663 synchronize_sched();
9666 * Now we are free to modify the group's share on each cpu
9667 * w/o tripping rebalance_share or load_balance_fair.
9669 tg
->shares
= shares
;
9670 for_each_possible_cpu(i
) {
9674 cfs_rq_set_shares(tg
->cfs_rq
[i
], 0);
9675 set_se_shares(tg
->se
[i
], shares
);
9679 * Enable load balance activity on this group, by inserting it back on
9680 * each cpu's rq->leaf_cfs_rq_list.
9682 spin_lock_irqsave(&task_group_lock
, flags
);
9683 for_each_possible_cpu(i
)
9684 register_fair_sched_group(tg
, i
);
9685 list_add_rcu(&tg
->siblings
, &tg
->parent
->children
);
9686 spin_unlock_irqrestore(&task_group_lock
, flags
);
9688 mutex_unlock(&shares_mutex
);
9692 unsigned long sched_group_shares(struct task_group
*tg
)
9698 #ifdef CONFIG_RT_GROUP_SCHED
9700 * Ensure that the real time constraints are schedulable.
9702 static DEFINE_MUTEX(rt_constraints_mutex
);
9704 static unsigned long to_ratio(u64 period
, u64 runtime
)
9706 if (runtime
== RUNTIME_INF
)
9709 return div64_u64(runtime
<< 20, period
);
9712 /* Must be called with tasklist_lock held */
9713 static inline int tg_has_rt_tasks(struct task_group
*tg
)
9715 struct task_struct
*g
, *p
;
9717 do_each_thread(g
, p
) {
9718 if (rt_task(p
) && rt_rq_of_se(&p
->rt
)->tg
== tg
)
9720 } while_each_thread(g
, p
);
9725 struct rt_schedulable_data
{
9726 struct task_group
*tg
;
9731 static int tg_schedulable(struct task_group
*tg
, void *data
)
9733 struct rt_schedulable_data
*d
= data
;
9734 struct task_group
*child
;
9735 unsigned long total
, sum
= 0;
9736 u64 period
, runtime
;
9738 period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
9739 runtime
= tg
->rt_bandwidth
.rt_runtime
;
9742 period
= d
->rt_period
;
9743 runtime
= d
->rt_runtime
;
9746 #ifdef CONFIG_USER_SCHED
9747 if (tg
== &root_task_group
) {
9748 period
= global_rt_period();
9749 runtime
= global_rt_runtime();
9754 * Cannot have more runtime than the period.
9756 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
9760 * Ensure we don't starve existing RT tasks.
9762 if (rt_bandwidth_enabled() && !runtime
&& tg_has_rt_tasks(tg
))
9765 total
= to_ratio(period
, runtime
);
9768 * Nobody can have more than the global setting allows.
9770 if (total
> to_ratio(global_rt_period(), global_rt_runtime()))
9774 * The sum of our children's runtime should not exceed our own.
9776 list_for_each_entry_rcu(child
, &tg
->children
, siblings
) {
9777 period
= ktime_to_ns(child
->rt_bandwidth
.rt_period
);
9778 runtime
= child
->rt_bandwidth
.rt_runtime
;
9780 if (child
== d
->tg
) {
9781 period
= d
->rt_period
;
9782 runtime
= d
->rt_runtime
;
9785 sum
+= to_ratio(period
, runtime
);
9794 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
9796 struct rt_schedulable_data data
= {
9798 .rt_period
= period
,
9799 .rt_runtime
= runtime
,
9802 return walk_tg_tree(tg_schedulable
, tg_nop
, &data
);
9805 static int tg_set_bandwidth(struct task_group
*tg
,
9806 u64 rt_period
, u64 rt_runtime
)
9810 mutex_lock(&rt_constraints_mutex
);
9811 read_lock(&tasklist_lock
);
9812 err
= __rt_schedulable(tg
, rt_period
, rt_runtime
);
9816 spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
9817 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
9818 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
9820 for_each_possible_cpu(i
) {
9821 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
9823 spin_lock(&rt_rq
->rt_runtime_lock
);
9824 rt_rq
->rt_runtime
= rt_runtime
;
9825 spin_unlock(&rt_rq
->rt_runtime_lock
);
9827 spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
9829 read_unlock(&tasklist_lock
);
9830 mutex_unlock(&rt_constraints_mutex
);
9835 int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
9837 u64 rt_runtime
, rt_period
;
9839 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
9840 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
9841 if (rt_runtime_us
< 0)
9842 rt_runtime
= RUNTIME_INF
;
9844 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
9847 long sched_group_rt_runtime(struct task_group
*tg
)
9851 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
9854 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
9855 do_div(rt_runtime_us
, NSEC_PER_USEC
);
9856 return rt_runtime_us
;
9859 int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
9861 u64 rt_runtime
, rt_period
;
9863 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
9864 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
9869 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
9872 long sched_group_rt_period(struct task_group
*tg
)
9876 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
9877 do_div(rt_period_us
, NSEC_PER_USEC
);
9878 return rt_period_us
;
9881 static int sched_rt_global_constraints(void)
9883 u64 runtime
, period
;
9886 if (sysctl_sched_rt_period
<= 0)
9889 runtime
= global_rt_runtime();
9890 period
= global_rt_period();
9893 * Sanity check on the sysctl variables.
9895 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
9898 mutex_lock(&rt_constraints_mutex
);
9899 read_lock(&tasklist_lock
);
9900 ret
= __rt_schedulable(NULL
, 0, 0);
9901 read_unlock(&tasklist_lock
);
9902 mutex_unlock(&rt_constraints_mutex
);
9907 int sched_rt_can_attach(struct task_group
*tg
, struct task_struct
*tsk
)
9909 /* Don't accept realtime tasks when there is no way for them to run */
9910 if (rt_task(tsk
) && tg
->rt_bandwidth
.rt_runtime
== 0)
9916 #else /* !CONFIG_RT_GROUP_SCHED */
9917 static int sched_rt_global_constraints(void)
9919 unsigned long flags
;
9922 if (sysctl_sched_rt_period
<= 0)
9926 * There's always some RT tasks in the root group
9927 * -- migration, kstopmachine etc..
9929 if (sysctl_sched_rt_runtime
== 0)
9932 spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
9933 for_each_possible_cpu(i
) {
9934 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
9936 spin_lock(&rt_rq
->rt_runtime_lock
);
9937 rt_rq
->rt_runtime
= global_rt_runtime();
9938 spin_unlock(&rt_rq
->rt_runtime_lock
);
9940 spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
9944 #endif /* CONFIG_RT_GROUP_SCHED */
9946 int sched_rt_handler(struct ctl_table
*table
, int write
,
9947 struct file
*filp
, void __user
*buffer
, size_t *lenp
,
9951 int old_period
, old_runtime
;
9952 static DEFINE_MUTEX(mutex
);
9955 old_period
= sysctl_sched_rt_period
;
9956 old_runtime
= sysctl_sched_rt_runtime
;
9958 ret
= proc_dointvec(table
, write
, filp
, buffer
, lenp
, ppos
);
9960 if (!ret
&& write
) {
9961 ret
= sched_rt_global_constraints();
9963 sysctl_sched_rt_period
= old_period
;
9964 sysctl_sched_rt_runtime
= old_runtime
;
9966 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
9967 def_rt_bandwidth
.rt_period
=
9968 ns_to_ktime(global_rt_period());
9971 mutex_unlock(&mutex
);
9976 #ifdef CONFIG_CGROUP_SCHED
9978 /* return corresponding task_group object of a cgroup */
9979 static inline struct task_group
*cgroup_tg(struct cgroup
*cgrp
)
9981 return container_of(cgroup_subsys_state(cgrp
, cpu_cgroup_subsys_id
),
9982 struct task_group
, css
);
9985 static struct cgroup_subsys_state
*
9986 cpu_cgroup_create(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9988 struct task_group
*tg
, *parent
;
9990 if (!cgrp
->parent
) {
9991 /* This is early initialization for the top cgroup */
9992 return &init_task_group
.css
;
9995 parent
= cgroup_tg(cgrp
->parent
);
9996 tg
= sched_create_group(parent
);
9998 return ERR_PTR(-ENOMEM
);
10004 cpu_cgroup_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10006 struct task_group
*tg
= cgroup_tg(cgrp
);
10008 sched_destroy_group(tg
);
10012 cpu_cgroup_can_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
10013 struct task_struct
*tsk
)
10015 #ifdef CONFIG_RT_GROUP_SCHED
10016 if (!sched_rt_can_attach(cgroup_tg(cgrp
), tsk
))
10019 /* We don't support RT-tasks being in separate groups */
10020 if (tsk
->sched_class
!= &fair_sched_class
)
10028 cpu_cgroup_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
10029 struct cgroup
*old_cont
, struct task_struct
*tsk
)
10031 sched_move_task(tsk
);
10034 #ifdef CONFIG_FAIR_GROUP_SCHED
10035 static int cpu_shares_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
10038 return sched_group_set_shares(cgroup_tg(cgrp
), shareval
);
10041 static u64
cpu_shares_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
10043 struct task_group
*tg
= cgroup_tg(cgrp
);
10045 return (u64
) tg
->shares
;
10047 #endif /* CONFIG_FAIR_GROUP_SCHED */
10049 #ifdef CONFIG_RT_GROUP_SCHED
10050 static int cpu_rt_runtime_write(struct cgroup
*cgrp
, struct cftype
*cft
,
10053 return sched_group_set_rt_runtime(cgroup_tg(cgrp
), val
);
10056 static s64
cpu_rt_runtime_read(struct cgroup
*cgrp
, struct cftype
*cft
)
10058 return sched_group_rt_runtime(cgroup_tg(cgrp
));
10061 static int cpu_rt_period_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
10064 return sched_group_set_rt_period(cgroup_tg(cgrp
), rt_period_us
);
10067 static u64
cpu_rt_period_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
10069 return sched_group_rt_period(cgroup_tg(cgrp
));
10071 #endif /* CONFIG_RT_GROUP_SCHED */
10073 static struct cftype cpu_files
[] = {
10074 #ifdef CONFIG_FAIR_GROUP_SCHED
10077 .read_u64
= cpu_shares_read_u64
,
10078 .write_u64
= cpu_shares_write_u64
,
10081 #ifdef CONFIG_RT_GROUP_SCHED
10083 .name
= "rt_runtime_us",
10084 .read_s64
= cpu_rt_runtime_read
,
10085 .write_s64
= cpu_rt_runtime_write
,
10088 .name
= "rt_period_us",
10089 .read_u64
= cpu_rt_period_read_uint
,
10090 .write_u64
= cpu_rt_period_write_uint
,
10095 static int cpu_cgroup_populate(struct cgroup_subsys
*ss
, struct cgroup
*cont
)
10097 return cgroup_add_files(cont
, ss
, cpu_files
, ARRAY_SIZE(cpu_files
));
10100 struct cgroup_subsys cpu_cgroup_subsys
= {
10102 .create
= cpu_cgroup_create
,
10103 .destroy
= cpu_cgroup_destroy
,
10104 .can_attach
= cpu_cgroup_can_attach
,
10105 .attach
= cpu_cgroup_attach
,
10106 .populate
= cpu_cgroup_populate
,
10107 .subsys_id
= cpu_cgroup_subsys_id
,
10111 #endif /* CONFIG_CGROUP_SCHED */
10113 #ifdef CONFIG_CGROUP_CPUACCT
10116 * CPU accounting code for task groups.
10118 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
10119 * (balbir@in.ibm.com).
10122 /* track cpu usage of a group of tasks and its child groups */
10124 struct cgroup_subsys_state css
;
10125 /* cpuusage holds pointer to a u64-type object on every cpu */
10127 struct percpu_counter cpustat
[CPUACCT_STAT_NSTATS
];
10128 struct cpuacct
*parent
;
10131 struct cgroup_subsys cpuacct_subsys
;
10133 /* return cpu accounting group corresponding to this container */
10134 static inline struct cpuacct
*cgroup_ca(struct cgroup
*cgrp
)
10136 return container_of(cgroup_subsys_state(cgrp
, cpuacct_subsys_id
),
10137 struct cpuacct
, css
);
10140 /* return cpu accounting group to which this task belongs */
10141 static inline struct cpuacct
*task_ca(struct task_struct
*tsk
)
10143 return container_of(task_subsys_state(tsk
, cpuacct_subsys_id
),
10144 struct cpuacct
, css
);
10147 /* create a new cpu accounting group */
10148 static struct cgroup_subsys_state
*cpuacct_create(
10149 struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10151 struct cpuacct
*ca
= kzalloc(sizeof(*ca
), GFP_KERNEL
);
10157 ca
->cpuusage
= alloc_percpu(u64
);
10161 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++)
10162 if (percpu_counter_init(&ca
->cpustat
[i
], 0))
10163 goto out_free_counters
;
10166 ca
->parent
= cgroup_ca(cgrp
->parent
);
10172 percpu_counter_destroy(&ca
->cpustat
[i
]);
10173 free_percpu(ca
->cpuusage
);
10177 return ERR_PTR(-ENOMEM
);
10180 /* destroy an existing cpu accounting group */
10182 cpuacct_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10184 struct cpuacct
*ca
= cgroup_ca(cgrp
);
10187 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++)
10188 percpu_counter_destroy(&ca
->cpustat
[i
]);
10189 free_percpu(ca
->cpuusage
);
10193 static u64
cpuacct_cpuusage_read(struct cpuacct
*ca
, int cpu
)
10195 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
10198 #ifndef CONFIG_64BIT
10200 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
10202 spin_lock_irq(&cpu_rq(cpu
)->lock
);
10204 spin_unlock_irq(&cpu_rq(cpu
)->lock
);
10212 static void cpuacct_cpuusage_write(struct cpuacct
*ca
, int cpu
, u64 val
)
10214 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
10216 #ifndef CONFIG_64BIT
10218 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
10220 spin_lock_irq(&cpu_rq(cpu
)->lock
);
10222 spin_unlock_irq(&cpu_rq(cpu
)->lock
);
10228 /* return total cpu usage (in nanoseconds) of a group */
10229 static u64
cpuusage_read(struct cgroup
*cgrp
, struct cftype
*cft
)
10231 struct cpuacct
*ca
= cgroup_ca(cgrp
);
10232 u64 totalcpuusage
= 0;
10235 for_each_present_cpu(i
)
10236 totalcpuusage
+= cpuacct_cpuusage_read(ca
, i
);
10238 return totalcpuusage
;
10241 static int cpuusage_write(struct cgroup
*cgrp
, struct cftype
*cftype
,
10244 struct cpuacct
*ca
= cgroup_ca(cgrp
);
10253 for_each_present_cpu(i
)
10254 cpuacct_cpuusage_write(ca
, i
, 0);
10260 static int cpuacct_percpu_seq_read(struct cgroup
*cgroup
, struct cftype
*cft
,
10261 struct seq_file
*m
)
10263 struct cpuacct
*ca
= cgroup_ca(cgroup
);
10267 for_each_present_cpu(i
) {
10268 percpu
= cpuacct_cpuusage_read(ca
, i
);
10269 seq_printf(m
, "%llu ", (unsigned long long) percpu
);
10271 seq_printf(m
, "\n");
10275 static const char *cpuacct_stat_desc
[] = {
10276 [CPUACCT_STAT_USER
] = "user",
10277 [CPUACCT_STAT_SYSTEM
] = "system",
10280 static int cpuacct_stats_show(struct cgroup
*cgrp
, struct cftype
*cft
,
10281 struct cgroup_map_cb
*cb
)
10283 struct cpuacct
*ca
= cgroup_ca(cgrp
);
10286 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++) {
10287 s64 val
= percpu_counter_read(&ca
->cpustat
[i
]);
10288 val
= cputime64_to_clock_t(val
);
10289 cb
->fill(cb
, cpuacct_stat_desc
[i
], val
);
10294 static struct cftype files
[] = {
10297 .read_u64
= cpuusage_read
,
10298 .write_u64
= cpuusage_write
,
10301 .name
= "usage_percpu",
10302 .read_seq_string
= cpuacct_percpu_seq_read
,
10306 .read_map
= cpuacct_stats_show
,
10310 static int cpuacct_populate(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10312 return cgroup_add_files(cgrp
, ss
, files
, ARRAY_SIZE(files
));
10316 * charge this task's execution time to its accounting group.
10318 * called with rq->lock held.
10320 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
)
10322 struct cpuacct
*ca
;
10325 if (unlikely(!cpuacct_subsys
.active
))
10328 cpu
= task_cpu(tsk
);
10334 for (; ca
; ca
= ca
->parent
) {
10335 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
10336 *cpuusage
+= cputime
;
10343 * Charge the system/user time to the task's accounting group.
10345 static void cpuacct_update_stats(struct task_struct
*tsk
,
10346 enum cpuacct_stat_index idx
, cputime_t val
)
10348 struct cpuacct
*ca
;
10350 if (unlikely(!cpuacct_subsys
.active
))
10357 percpu_counter_add(&ca
->cpustat
[idx
], val
);
10363 struct cgroup_subsys cpuacct_subsys
= {
10365 .create
= cpuacct_create
,
10366 .destroy
= cpuacct_destroy
,
10367 .populate
= cpuacct_populate
,
10368 .subsys_id
= cpuacct_subsys_id
,
10370 #endif /* CONFIG_CGROUP_CPUACCT */