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Linux/kernel/sched/sched.h

  1 
  2 #include <linux/sched.h>
  3 #include <linux/mutex.h>
  4 #include <linux/spinlock.h>
  5 #include <linux/stop_machine.h>
  6 
  7 #include "cpupri.h"
  8 
  9 extern __read_mostly int scheduler_running;
 10 
 11 /*
 12  * Convert user-nice values [ -20 ... 0 ... 19 ]
 13  * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
 14  * and back.
 15  */
 16 #define NICE_TO_PRIO(nice)      (MAX_RT_PRIO + (nice) + 20)
 17 #define PRIO_TO_NICE(prio)      ((prio) - MAX_RT_PRIO - 20)
 18 #define TASK_NICE(p)            PRIO_TO_NICE((p)->static_prio)
 19 
 20 /*
 21  * 'User priority' is the nice value converted to something we
 22  * can work with better when scaling various scheduler parameters,
 23  * it's a [ 0 ... 39 ] range.
 24  */
 25 #define USER_PRIO(p)            ((p)-MAX_RT_PRIO)
 26 #define TASK_USER_PRIO(p)       USER_PRIO((p)->static_prio)
 27 #define MAX_USER_PRIO           (USER_PRIO(MAX_PRIO))
 28 
 29 /*
 30  * Helpers for converting nanosecond timing to jiffy resolution
 31  */
 32 #define NS_TO_JIFFIES(TIME)     ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
 33 
 34 #define NICE_0_LOAD             SCHED_LOAD_SCALE
 35 #define NICE_0_SHIFT            SCHED_LOAD_SHIFT
 36 
 37 /*
 38  * These are the 'tuning knobs' of the scheduler:
 39  *
 40  * default timeslice is 100 msecs (used only for SCHED_RR tasks).
 41  * Timeslices get refilled after they expire.
 42  */
 43 #define DEF_TIMESLICE           (100 * HZ / 1000)
 44 
 45 /*
 46  * single value that denotes runtime == period, ie unlimited time.
 47  */
 48 #define RUNTIME_INF     ((u64)~0ULL)
 49 
 50 static inline int rt_policy(int policy)
 51 {
 52         if (policy == SCHED_FIFO || policy == SCHED_RR)
 53                 return 1;
 54         return 0;
 55 }
 56 
 57 static inline int task_has_rt_policy(struct task_struct *p)
 58 {
 59         return rt_policy(p->policy);
 60 }
 61 
 62 /*
 63  * This is the priority-queue data structure of the RT scheduling class:
 64  */
 65 struct rt_prio_array {
 66         DECLARE_BITMAP(bitmap, MAX_RT_PRIO+1); /* include 1 bit for delimiter */
 67         struct list_head queue[MAX_RT_PRIO];
 68 };
 69 
 70 struct rt_bandwidth {
 71         /* nests inside the rq lock: */
 72         raw_spinlock_t          rt_runtime_lock;
 73         ktime_t                 rt_period;
 74         u64                     rt_runtime;
 75         struct hrtimer          rt_period_timer;
 76 };
 77 
 78 extern struct mutex sched_domains_mutex;
 79 
 80 #ifdef CONFIG_CGROUP_SCHED
 81 
 82 #include <linux/cgroup.h>
 83 
 84 struct cfs_rq;
 85 struct rt_rq;
 86 
 87 static LIST_HEAD(task_groups);
 88 
 89 struct cfs_bandwidth {
 90 #ifdef CONFIG_CFS_BANDWIDTH
 91         raw_spinlock_t lock;
 92         ktime_t period;
 93         u64 quota, runtime;
 94         s64 hierarchal_quota;
 95         u64 runtime_expires;
 96 
 97         int idle, timer_active;
 98         struct hrtimer period_timer, slack_timer;
 99         struct list_head throttled_cfs_rq;
100 
101         /* statistics */
102         int nr_periods, nr_throttled;
103         u64 throttled_time;
104 #endif
105 };
106 
107 /* task group related information */
108 struct task_group {
109         struct cgroup_subsys_state css;
110 
111 #ifdef CONFIG_FAIR_GROUP_SCHED
112         /* schedulable entities of this group on each cpu */
113         struct sched_entity **se;
114         /* runqueue "owned" by this group on each cpu */
115         struct cfs_rq **cfs_rq;
116         unsigned long shares;
117 
118         atomic_t load_weight;
119 #endif
120 
121 #ifdef CONFIG_RT_GROUP_SCHED
122         struct sched_rt_entity **rt_se;
123         struct rt_rq **rt_rq;
124 
125         struct rt_bandwidth rt_bandwidth;
126 #endif
127 
128         struct rcu_head rcu;
129         struct list_head list;
130 
131         struct task_group *parent;
132         struct list_head siblings;
133         struct list_head children;
134 
135 #ifdef CONFIG_SCHED_AUTOGROUP
136         struct autogroup *autogroup;
137 #endif
138 
139         struct cfs_bandwidth cfs_bandwidth;
140 };
141 
142 #ifdef CONFIG_FAIR_GROUP_SCHED
143 #define ROOT_TASK_GROUP_LOAD    NICE_0_LOAD
144 
145 /*
146  * A weight of 0 or 1 can cause arithmetics problems.
147  * A weight of a cfs_rq is the sum of weights of which entities
148  * are queued on this cfs_rq, so a weight of a entity should not be
149  * too large, so as the shares value of a task group.
150  * (The default weight is 1024 - so there's no practical
151  *  limitation from this.)
152  */
153 #define MIN_SHARES      (1UL <<  1)
154 #define MAX_SHARES      (1UL << 18)
155 #endif
156 
157 /* Default task group.
158  *      Every task in system belong to this group at bootup.
159  */
160 extern struct task_group root_task_group;
161 
162 typedef int (*tg_visitor)(struct task_group *, void *);
163 
164 extern int walk_tg_tree_from(struct task_group *from,
165                              tg_visitor down, tg_visitor up, void *data);
166 
167 /*
168  * Iterate the full tree, calling @down when first entering a node and @up when
169  * leaving it for the final time.
170  *
171  * Caller must hold rcu_lock or sufficient equivalent.
172  */
173 static inline int walk_tg_tree(tg_visitor down, tg_visitor up, void *data)
174 {
175         return walk_tg_tree_from(&root_task_group, down, up, data);
176 }
177 
178 extern int tg_nop(struct task_group *tg, void *data);
179 
180 extern void free_fair_sched_group(struct task_group *tg);
181 extern int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent);
182 extern void unregister_fair_sched_group(struct task_group *tg, int cpu);
183 extern void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
184                         struct sched_entity *se, int cpu,
185                         struct sched_entity *parent);
186 extern void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b);
187 extern int sched_group_set_shares(struct task_group *tg, unsigned long shares);
188 
189 extern void __refill_cfs_bandwidth_runtime(struct cfs_bandwidth *cfs_b);
190 extern void __start_cfs_bandwidth(struct cfs_bandwidth *cfs_b);
191 extern void unthrottle_cfs_rq(struct cfs_rq *cfs_rq);
192 
193 extern void free_rt_sched_group(struct task_group *tg);
194 extern int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent);
195 extern void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
196                 struct sched_rt_entity *rt_se, int cpu,
197                 struct sched_rt_entity *parent);
198 
199 #else /* CONFIG_CGROUP_SCHED */
200 
201 struct cfs_bandwidth { };
202 
203 #endif  /* CONFIG_CGROUP_SCHED */
204 
205 /* CFS-related fields in a runqueue */
206 struct cfs_rq {
207         struct load_weight load;
208         unsigned long nr_running, h_nr_running;
209 
210         u64 exec_clock;
211         u64 min_vruntime;
212 #ifndef CONFIG_64BIT
213         u64 min_vruntime_copy;
214 #endif
215 
216         struct rb_root tasks_timeline;
217         struct rb_node *rb_leftmost;
218 
219         struct list_head tasks;
220         struct list_head *balance_iterator;
221 
222         /*
223          * 'curr' points to currently running entity on this cfs_rq.
224          * It is set to NULL otherwise (i.e when none are currently running).
225          */
226         struct sched_entity *curr, *next, *last, *skip;
227 
228 #ifdef  CONFIG_SCHED_DEBUG
229         unsigned int nr_spread_over;
230 #endif
231 
232 #ifdef CONFIG_FAIR_GROUP_SCHED
233         struct rq *rq;  /* cpu runqueue to which this cfs_rq is attached */
234 
235         /*
236          * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
237          * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
238          * (like users, containers etc.)
239          *
240          * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
241          * list is used during load balance.
242          */
243         int on_list;
244         struct list_head leaf_cfs_rq_list;
245         struct task_group *tg;  /* group that "owns" this runqueue */
246 
247 #ifdef CONFIG_SMP
248         /*
249          * the part of load.weight contributed by tasks
250          */
251         unsigned long task_weight;
252 
253         /*
254          *   h_load = weight * f(tg)
255          *
256          * Where f(tg) is the recursive weight fraction assigned to
257          * this group.
258          */
259         unsigned long h_load;
260 
261         /*
262          * Maintaining per-cpu shares distribution for group scheduling
263          *
264          * load_stamp is the last time we updated the load average
265          * load_last is the last time we updated the load average and saw load
266          * load_unacc_exec_time is currently unaccounted execution time
267          */
268         u64 load_avg;
269         u64 load_period;
270         u64 load_stamp, load_last, load_unacc_exec_time;
271 
272         unsigned long load_contribution;
273 #endif /* CONFIG_SMP */
274 #ifdef CONFIG_CFS_BANDWIDTH
275         int runtime_enabled;
276         u64 runtime_expires;
277         s64 runtime_remaining;
278 
279         u64 throttled_timestamp;
280         int throttled, throttle_count;
281         struct list_head throttled_list;
282 #endif /* CONFIG_CFS_BANDWIDTH */
283 #endif /* CONFIG_FAIR_GROUP_SCHED */
284 };
285 
286 static inline int rt_bandwidth_enabled(void)
287 {
288         return sysctl_sched_rt_runtime >= 0;
289 }
290 
291 /* Real-Time classes' related field in a runqueue: */
292 struct rt_rq {
293         struct rt_prio_array active;
294         unsigned long rt_nr_running;
295 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
296         struct {
297                 int curr; /* highest queued rt task prio */
298 #ifdef CONFIG_SMP
299                 int next; /* next highest */
300 #endif
301         } highest_prio;
302 #endif
303 #ifdef CONFIG_SMP
304         unsigned long rt_nr_migratory;
305         unsigned long rt_nr_total;
306         int overloaded;
307         struct plist_head pushable_tasks;
308 #endif
309         int rt_throttled;
310         u64 rt_time;
311         u64 rt_runtime;
312         /* Nests inside the rq lock: */
313         raw_spinlock_t rt_runtime_lock;
314 
315 #ifdef CONFIG_RT_GROUP_SCHED
316         unsigned long rt_nr_boosted;
317 
318         struct rq *rq;
319         struct list_head leaf_rt_rq_list;
320         struct task_group *tg;
321 #endif
322 };
323 
324 #ifdef CONFIG_SMP
325 
326 /*
327  * We add the notion of a root-domain which will be used to define per-domain
328  * variables. Each exclusive cpuset essentially defines an island domain by
329  * fully partitioning the member cpus from any other cpuset. Whenever a new
330  * exclusive cpuset is created, we also create and attach a new root-domain
331  * object.
332  *
333  */
334 struct root_domain {
335         atomic_t refcount;
336         atomic_t rto_count;
337         struct rcu_head rcu;
338         cpumask_var_t span;
339         cpumask_var_t online;
340 
341         /*
342          * The "RT overload" flag: it gets set if a CPU has more than
343          * one runnable RT task.
344          */
345         cpumask_var_t rto_mask;
346         struct cpupri cpupri;
347 };
348 
349 extern struct root_domain def_root_domain;
350 
351 #endif /* CONFIG_SMP */
352 
353 /*
354  * This is the main, per-CPU runqueue data structure.
355  *
356  * Locking rule: those places that want to lock multiple runqueues
357  * (such as the load balancing or the thread migration code), lock
358  * acquire operations must be ordered by ascending &runqueue.
359  */
360 struct rq {
361         /* runqueue lock: */
362         raw_spinlock_t lock;
363 
364         /*
365          * nr_running and cpu_load should be in the same cacheline because
366          * remote CPUs use both these fields when doing load calculation.
367          */
368         unsigned long nr_running;
369         #define CPU_LOAD_IDX_MAX 5
370         unsigned long cpu_load[CPU_LOAD_IDX_MAX];
371         unsigned long last_load_update_tick;
372 #ifdef CONFIG_NO_HZ
373         u64 nohz_stamp;
374         unsigned long nohz_flags;
375 #endif
376         int skip_clock_update;
377 
378         /* capture load from *all* tasks on this cpu: */
379         struct load_weight load;
380         unsigned long nr_load_updates;
381         u64 nr_switches;
382 
383         struct cfs_rq cfs;
384         struct rt_rq rt;
385 
386 #ifdef CONFIG_FAIR_GROUP_SCHED
387         /* list of leaf cfs_rq on this cpu: */
388         struct list_head leaf_cfs_rq_list;
389 #endif
390 #ifdef CONFIG_RT_GROUP_SCHED
391         struct list_head leaf_rt_rq_list;
392 #endif
393 
394         /*
395          * This is part of a global counter where only the total sum
396          * over all CPUs matters. A task can increase this counter on
397          * one CPU and if it got migrated afterwards it may decrease
398          * it on another CPU. Always updated under the runqueue lock:
399          */
400         unsigned long nr_uninterruptible;
401 
402         struct task_struct *curr, *idle, *stop;
403         unsigned long next_balance;
404         struct mm_struct *prev_mm;
405 
406         u64 clock;
407         u64 clock_task;
408 
409         atomic_t nr_iowait;
410 
411 #ifdef CONFIG_SMP
412         struct root_domain *rd;
413         struct sched_domain *sd;
414 
415         unsigned long cpu_power;
416 
417         unsigned char idle_balance;
418         /* For active balancing */
419         int post_schedule;
420         int active_balance;
421         int push_cpu;
422         struct cpu_stop_work active_balance_work;
423         /* cpu of this runqueue: */
424         int cpu;
425         int online;
426 
427         u64 rt_avg;
428         u64 age_stamp;
429         u64 idle_stamp;
430         u64 avg_idle;
431 #endif
432 
433 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
434         u64 prev_irq_time;
435 #endif
436 #ifdef CONFIG_PARAVIRT
437         u64 prev_steal_time;
438 #endif
439 #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
440         u64 prev_steal_time_rq;
441 #endif
442 
443         /* calc_load related fields */
444         unsigned long calc_load_update;
445         long calc_load_active;
446 
447 #ifdef CONFIG_SCHED_HRTICK
448 #ifdef CONFIG_SMP
449         int hrtick_csd_pending;
450         struct call_single_data hrtick_csd;
451 #endif
452         struct hrtimer hrtick_timer;
453 #endif
454 
455 #ifdef CONFIG_SCHEDSTATS
456         /* latency stats */
457         struct sched_info rq_sched_info;
458         unsigned long long rq_cpu_time;
459         /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
460 
461         /* sys_sched_yield() stats */
462         unsigned int yld_count;
463 
464         /* schedule() stats */
465         unsigned int sched_switch;
466         unsigned int sched_count;
467         unsigned int sched_goidle;
468 
469         /* try_to_wake_up() stats */
470         unsigned int ttwu_count;
471         unsigned int ttwu_local;
472 #endif
473 
474 #ifdef CONFIG_SMP
475         struct llist_head wake_list;
476 #endif
477 };
478 
479 static inline int cpu_of(struct rq *rq)
480 {
481 #ifdef CONFIG_SMP
482         return rq->cpu;
483 #else
484         return 0;
485 #endif
486 }
487 
488 DECLARE_PER_CPU(struct rq, runqueues);
489 
490 #define cpu_rq(cpu)             (&per_cpu(runqueues, (cpu)))
491 #define this_rq()               (&__get_cpu_var(runqueues))
492 #define task_rq(p)              cpu_rq(task_cpu(p))
493 #define cpu_curr(cpu)           (cpu_rq(cpu)->curr)
494 #define raw_rq()                (&__raw_get_cpu_var(runqueues))
495 
496 #ifdef CONFIG_SMP
497 
498 #define rcu_dereference_check_sched_domain(p) \
499         rcu_dereference_check((p), \
500                               lockdep_is_held(&sched_domains_mutex))
501 
502 /*
503  * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
504  * See detach_destroy_domains: synchronize_sched for details.
505  *
506  * The domain tree of any CPU may only be accessed from within
507  * preempt-disabled sections.
508  */
509 #define for_each_domain(cpu, __sd) \
510         for (__sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd); \
511                         __sd; __sd = __sd->parent)
512 
513 #define for_each_lower_domain(sd) for (; sd; sd = sd->child)
514 
515 /**
516  * highest_flag_domain - Return highest sched_domain containing flag.
517  * @cpu:        The cpu whose highest level of sched domain is to
518  *              be returned.
519  * @flag:       The flag to check for the highest sched_domain
520  *              for the given cpu.
521  *
522  * Returns the highest sched_domain of a cpu which contains the given flag.
523  */
524 static inline struct sched_domain *highest_flag_domain(int cpu, int flag)
525 {
526         struct sched_domain *sd, *hsd = NULL;
527 
528         for_each_domain(cpu, sd) {
529                 if (!(sd->flags & flag))
530                         break;
531                 hsd = sd;
532         }
533 
534         return hsd;
535 }
536 
537 DECLARE_PER_CPU(struct sched_domain *, sd_llc);
538 DECLARE_PER_CPU(int, sd_llc_id);
539 
540 #endif /* CONFIG_SMP */
541 
542 #include "stats.h"
543 #include "auto_group.h"
544 
545 #ifdef CONFIG_CGROUP_SCHED
546 
547 /*
548  * Return the group to which this tasks belongs.
549  *
550  * We use task_subsys_state_check() and extend the RCU verification with
551  * pi->lock and rq->lock because cpu_cgroup_attach() holds those locks for each
552  * task it moves into the cgroup. Therefore by holding either of those locks,
553  * we pin the task to the current cgroup.
554  */
555 static inline struct task_group *task_group(struct task_struct *p)
556 {
557         struct task_group *tg;
558         struct cgroup_subsys_state *css;
559 
560         css = task_subsys_state_check(p, cpu_cgroup_subsys_id,
561                         lockdep_is_held(&p->pi_lock) ||
562                         lockdep_is_held(&task_rq(p)->lock));
563         tg = container_of(css, struct task_group, css);
564 
565         return autogroup_task_group(p, tg);
566 }
567 
568 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
569 static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
570 {
571 #if defined(CONFIG_FAIR_GROUP_SCHED) || defined(CONFIG_RT_GROUP_SCHED)
572         struct task_group *tg = task_group(p);
573 #endif
574 
575 #ifdef CONFIG_FAIR_GROUP_SCHED
576         p->se.cfs_rq = tg->cfs_rq[cpu];
577         p->se.parent = tg->se[cpu];
578 #endif
579 
580 #ifdef CONFIG_RT_GROUP_SCHED
581         p->rt.rt_rq  = tg->rt_rq[cpu];
582         p->rt.parent = tg->rt_se[cpu];
583 #endif
584 }
585 
586 #else /* CONFIG_CGROUP_SCHED */
587 
588 static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { }
589 static inline struct task_group *task_group(struct task_struct *p)
590 {
591         return NULL;
592 }
593 
594 #endif /* CONFIG_CGROUP_SCHED */
595 
596 static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
597 {
598         set_task_rq(p, cpu);
599 #ifdef CONFIG_SMP
600         /*
601          * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
602          * successfuly executed on another CPU. We must ensure that updates of
603          * per-task data have been completed by this moment.
604          */
605         smp_wmb();
606         task_thread_info(p)->cpu = cpu;
607 #endif
608 }
609 
610 /*
611  * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
612  */
613 #ifdef CONFIG_SCHED_DEBUG
614 # include <linux/jump_label.h>
615 # define const_debug __read_mostly
616 #else
617 # define const_debug const
618 #endif
619 
620 extern const_debug unsigned int sysctl_sched_features;
621 
622 #define SCHED_FEAT(name, enabled)       \
623         __SCHED_FEAT_##name ,
624 
625 enum {
626 #include "features.h"
627         __SCHED_FEAT_NR,
628 };
629 
630 #undef SCHED_FEAT
631 
632 #if defined(CONFIG_SCHED_DEBUG) && defined(HAVE_JUMP_LABEL)
633 static __always_inline bool static_branch__true(struct jump_label_key *key)
634 {
635         return likely(static_branch(key)); /* Not out of line branch. */
636 }
637 
638 static __always_inline bool static_branch__false(struct jump_label_key *key)
639 {
640         return unlikely(static_branch(key)); /* Out of line branch. */
641 }
642 
643 #define SCHED_FEAT(name, enabled)                                       \
644 static __always_inline bool static_branch_##name(struct jump_label_key *key) \
645 {                                                                       \
646         return static_branch__##enabled(key);                           \
647 }
648 
649 #include "features.h"
650 
651 #undef SCHED_FEAT
652 
653 extern struct jump_label_key sched_feat_keys[__SCHED_FEAT_NR];
654 #define sched_feat(x) (static_branch_##x(&sched_feat_keys[__SCHED_FEAT_##x]))
655 #else /* !(SCHED_DEBUG && HAVE_JUMP_LABEL) */
656 #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
657 #endif /* SCHED_DEBUG && HAVE_JUMP_LABEL */
658 
659 static inline u64 global_rt_period(void)
660 {
661         return (u64)sysctl_sched_rt_period * NSEC_PER_USEC;
662 }
663 
664 static inline u64 global_rt_runtime(void)
665 {
666         if (sysctl_sched_rt_runtime < 0)
667                 return RUNTIME_INF;
668 
669         return (u64)sysctl_sched_rt_runtime * NSEC_PER_USEC;
670 }
671 
672 
673 
674 static inline int task_current(struct rq *rq, struct task_struct *p)
675 {
676         return rq->curr == p;
677 }
678 
679 static inline int task_running(struct rq *rq, struct task_struct *p)
680 {
681 #ifdef CONFIG_SMP
682         return p->on_cpu;
683 #else
684         return task_current(rq, p);
685 #endif
686 }
687 
688 
689 #ifndef prepare_arch_switch
690 # define prepare_arch_switch(next)      do { } while (0)
691 #endif
692 #ifndef finish_arch_switch
693 # define finish_arch_switch(prev)       do { } while (0)
694 #endif
695 
696 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
697 static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
698 {
699 #ifdef CONFIG_SMP
700         /*
701          * We can optimise this out completely for !SMP, because the
702          * SMP rebalancing from interrupt is the only thing that cares
703          * here.
704          */
705         next->on_cpu = 1;
706 #endif
707 }
708 
709 static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
710 {
711 #ifdef CONFIG_SMP
712         /*
713          * After ->on_cpu is cleared, the task can be moved to a different CPU.
714          * We must ensure this doesn't happen until the switch is completely
715          * finished.
716          */
717         smp_wmb();
718         prev->on_cpu = 0;
719 #endif
720 #ifdef CONFIG_DEBUG_SPINLOCK
721         /* this is a valid case when another task releases the spinlock */
722         rq->lock.owner = current;
723 #endif
724         /*
725          * If we are tracking spinlock dependencies then we have to
726          * fix up the runqueue lock - which gets 'carried over' from
727          * prev into current:
728          */
729         spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_);
730 
731         raw_spin_unlock_irq(&rq->lock);
732 }
733 
734 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
735 static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
736 {
737 #ifdef CONFIG_SMP
738         /*
739          * We can optimise this out completely for !SMP, because the
740          * SMP rebalancing from interrupt is the only thing that cares
741          * here.
742          */
743         next->on_cpu = 1;
744 #endif
745 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
746         raw_spin_unlock_irq(&rq->lock);
747 #else
748         raw_spin_unlock(&rq->lock);
749 #endif
750 }
751 
752 static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
753 {
754 #ifdef CONFIG_SMP
755         /*
756          * After ->on_cpu is cleared, the task can be moved to a different CPU.
757          * We must ensure this doesn't happen until the switch is completely
758          * finished.
759          */
760         smp_wmb();
761         prev->on_cpu = 0;
762 #endif
763 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
764         local_irq_enable();
765 #endif
766 }
767 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
768 
769 
770 static inline void update_load_add(struct load_weight *lw, unsigned long inc)
771 {
772         lw->weight += inc;
773         lw->inv_weight = 0;
774 }
775 
776 static inline void update_load_sub(struct load_weight *lw, unsigned long dec)
777 {
778         lw->weight -= dec;
779         lw->inv_weight = 0;
780 }
781 
782 static inline void update_load_set(struct load_weight *lw, unsigned long w)
783 {
784         lw->weight = w;
785         lw->inv_weight = 0;
786 }
787 
788 /*
789  * To aid in avoiding the subversion of "niceness" due to uneven distribution
790  * of tasks with abnormal "nice" values across CPUs the contribution that
791  * each task makes to its run queue's load is weighted according to its
792  * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
793  * scaled version of the new time slice allocation that they receive on time
794  * slice expiry etc.
795  */
796 
797 #define WEIGHT_IDLEPRIO                3
798 #define WMULT_IDLEPRIO         1431655765
799 
800 /*
801  * Nice levels are multiplicative, with a gentle 10% change for every
802  * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
803  * nice 1, it will get ~10% less CPU time than another CPU-bound task
804  * that remained on nice 0.
805  *
806  * The "10% effect" is relative and cumulative: from _any_ nice level,
807  * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
808  * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
809  * If a task goes up by ~10% and another task goes down by ~10% then
810  * the relative distance between them is ~25%.)
811  */
812 static const int prio_to_weight[40] = {
813  /* -20 */     88761,     71755,     56483,     46273,     36291,
814  /* -15 */     29154,     23254,     18705,     14949,     11916,
815  /* -10 */      9548,      7620,      6100,      4904,      3906,
816  /*  -5 */      3121,      2501,      1991,      1586,      1277,
817  /*   0 */      1024,       820,       655,       526,       423,
818  /*   5 */       335,       272,       215,       172,       137,
819  /*  10 */       110,        87,        70,        56,        45,
820  /*  15 */        36,        29,        23,        18,        15,
821 };
822 
823 /*
824  * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
825  *
826  * In cases where the weight does not change often, we can use the
827  * precalculated inverse to speed up arithmetics by turning divisions
828  * into multiplications:
829  */
830 static const u32 prio_to_wmult[40] = {
831  /* -20 */     48388,     59856,     76040,     92818,    118348,
832  /* -15 */    147320,    184698,    229616,    287308,    360437,
833  /* -10 */    449829,    563644,    704093,    875809,   1099582,
834  /*  -5 */   1376151,   1717300,   2157191,   2708050,   3363326,
835  /*   0 */   4194304,   5237765,   6557202,   8165337,  10153587,
836  /*   5 */  12820798,  15790321,  19976592,  24970740,  31350126,
837  /*  10 */  39045157,  49367440,  61356676,  76695844,  95443717,
838  /*  15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
839 };
840 
841 /* Time spent by the tasks of the cpu accounting group executing in ... */
842 enum cpuacct_stat_index {
843         CPUACCT_STAT_USER,      /* ... user mode */
844         CPUACCT_STAT_SYSTEM,    /* ... kernel mode */
845 
846         CPUACCT_STAT_NSTATS,
847 };
848 
849 
850 #define sched_class_highest (&stop_sched_class)
851 #define for_each_class(class) \
852    for (class = sched_class_highest; class; class = class->next)
853 
854 extern const struct sched_class stop_sched_class;
855 extern const struct sched_class rt_sched_class;
856 extern const struct sched_class fair_sched_class;
857 extern const struct sched_class idle_sched_class;
858 
859 
860 #ifdef CONFIG_SMP
861 
862 extern void trigger_load_balance(struct rq *rq, int cpu);
863 extern void idle_balance(int this_cpu, struct rq *this_rq);
864 
865 #else   /* CONFIG_SMP */
866 
867 static inline void idle_balance(int cpu, struct rq *rq)
868 {
869 }
870 
871 #endif
872 
873 extern void sysrq_sched_debug_show(void);
874 extern void sched_init_granularity(void);
875 extern void update_max_interval(void);
876 extern void update_group_power(struct sched_domain *sd, int cpu);
877 extern int update_runtime(struct notifier_block *nfb, unsigned long action, void *hcpu);
878 extern void init_sched_rt_class(void);
879 extern void init_sched_fair_class(void);
880 
881 extern void resched_task(struct task_struct *p);
882 extern void resched_cpu(int cpu);
883 
884 extern struct rt_bandwidth def_rt_bandwidth;
885 extern void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime);
886 
887 extern void update_cpu_load(struct rq *this_rq);
888 
889 #ifdef CONFIG_CGROUP_CPUACCT
890 #include <linux/cgroup.h>
891 /* track cpu usage of a group of tasks and its child groups */
892 struct cpuacct {
893         struct cgroup_subsys_state css;
894         /* cpuusage holds pointer to a u64-type object on every cpu */
895         u64 __percpu *cpuusage;
896         struct kernel_cpustat __percpu *cpustat;
897 };
898 
899 /* return cpu accounting group corresponding to this container */
900 static inline struct cpuacct *cgroup_ca(struct cgroup *cgrp)
901 {
902         return container_of(cgroup_subsys_state(cgrp, cpuacct_subsys_id),
903                             struct cpuacct, css);
904 }
905 
906 /* return cpu accounting group to which this task belongs */
907 static inline struct cpuacct *task_ca(struct task_struct *tsk)
908 {
909         return container_of(task_subsys_state(tsk, cpuacct_subsys_id),
910                             struct cpuacct, css);
911 }
912 
913 static inline struct cpuacct *parent_ca(struct cpuacct *ca)
914 {
915         if (!ca || !ca->css.cgroup->parent)
916                 return NULL;
917         return cgroup_ca(ca->css.cgroup->parent);
918 }
919 
920 extern void cpuacct_charge(struct task_struct *tsk, u64 cputime);
921 #else
922 static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}
923 #endif
924 
925 static inline void inc_nr_running(struct rq *rq)
926 {
927         rq->nr_running++;
928 }
929 
930 static inline void dec_nr_running(struct rq *rq)
931 {
932         rq->nr_running--;
933 }
934 
935 extern void update_rq_clock(struct rq *rq);
936 
937 extern void activate_task(struct rq *rq, struct task_struct *p, int flags);
938 extern void deactivate_task(struct rq *rq, struct task_struct *p, int flags);
939 
940 extern void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags);
941 
942 extern const_debug unsigned int sysctl_sched_time_avg;
943 extern const_debug unsigned int sysctl_sched_nr_migrate;
944 extern const_debug unsigned int sysctl_sched_migration_cost;
945 
946 static inline u64 sched_avg_period(void)
947 {
948         return (u64)sysctl_sched_time_avg * NSEC_PER_MSEC / 2;
949 }
950 
951 void calc_load_account_idle(struct rq *this_rq);
952 
953 #ifdef CONFIG_SCHED_HRTICK
954 
955 /*
956  * Use hrtick when:
957  *  - enabled by features
958  *  - hrtimer is actually high res
959  */
960 static inline int hrtick_enabled(struct rq *rq)
961 {
962         if (!sched_feat(HRTICK))
963                 return 0;
964         if (!cpu_active(cpu_of(rq)))
965                 return 0;
966         return hrtimer_is_hres_active(&rq->hrtick_timer);
967 }
968 
969 void hrtick_start(struct rq *rq, u64 delay);
970 
971 #else
972 
973 static inline int hrtick_enabled(struct rq *rq)
974 {
975         return 0;
976 }
977 
978 #endif /* CONFIG_SCHED_HRTICK */
979 
980 #ifdef CONFIG_SMP
981 extern void sched_avg_update(struct rq *rq);
982 static inline void sched_rt_avg_update(struct rq *rq, u64 rt_delta)
983 {
984         rq->rt_avg += rt_delta;
985         sched_avg_update(rq);
986 }
987 #else
988 static inline void sched_rt_avg_update(struct rq *rq, u64 rt_delta) { }
989 static inline void sched_avg_update(struct rq *rq) { }
990 #endif
991 
992 extern void start_bandwidth_timer(struct hrtimer *period_timer, ktime_t period);
993 
994 #ifdef CONFIG_SMP
995 #ifdef CONFIG_PREEMPT
996 
997 static inline void double_rq_lock(struct rq *rq1, struct rq *rq2);
998 
999 /*
1000  * fair double_lock_balance: Safely acquires both rq->locks in a fair
1001  * way at the expense of forcing extra atomic operations in all
1002  * invocations.  This assures that the double_lock is acquired using the
1003  * same underlying policy as the spinlock_t on this architecture, which
1004  * reduces latency compared to the unfair variant below.  However, it
1005  * also adds more overhead and therefore may reduce throughput.
1006  */
1007 static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
1008         __releases(this_rq->lock)
1009         __acquires(busiest->lock)
1010         __acquires(this_rq->lock)
1011 {
1012         raw_spin_unlock(&this_rq->lock);
1013         double_rq_lock(this_rq, busiest);
1014 
1015         return 1;
1016 }
1017 
1018 #else
1019 /*
1020  * Unfair double_lock_balance: Optimizes throughput at the expense of
1021  * latency by eliminating extra atomic operations when the locks are
1022  * already in proper order on entry.  This favors lower cpu-ids and will
1023  * grant the double lock to lower cpus over higher ids under contention,
1024  * regardless of entry order into the function.
1025  */
1026 static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
1027         __releases(this_rq->lock)
1028         __acquires(busiest->lock)
1029         __acquires(this_rq->lock)
1030 {
1031         int ret = 0;
1032 
1033         if (unlikely(!raw_spin_trylock(&busiest->lock))) {
1034                 if (busiest < this_rq) {
1035                         raw_spin_unlock(&this_rq->lock);
1036                         raw_spin_lock(&busiest->lock);
1037                         raw_spin_lock_nested(&this_rq->lock,
1038                                               SINGLE_DEPTH_NESTING);
1039                         ret = 1;
1040                 } else
1041                         raw_spin_lock_nested(&busiest->lock,
1042                                               SINGLE_DEPTH_NESTING);
1043         }
1044         return ret;
1045 }
1046 
1047 #endif /* CONFIG_PREEMPT */
1048 
1049 /*
1050  * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
1051  */
1052 static inline int double_lock_balance(struct rq *this_rq, struct rq *busiest)
1053 {
1054         if (unlikely(!irqs_disabled())) {
1055                 /* printk() doesn't work good under rq->lock */
1056                 raw_spin_unlock(&this_rq->lock);
1057                 BUG_ON(1);
1058         }
1059 
1060         return _double_lock_balance(this_rq, busiest);
1061 }
1062 
1063 static inline void double_unlock_balance(struct rq *this_rq, struct rq *busiest)
1064         __releases(busiest->lock)
1065 {
1066         raw_spin_unlock(&busiest->lock);
1067         lock_set_subclass(&this_rq->lock.dep_map, 0, _RET_IP_);
1068 }
1069 
1070 /*
1071  * double_rq_lock - safely lock two runqueues
1072  *
1073  * Note this does not disable interrupts like task_rq_lock,
1074  * you need to do so manually before calling.
1075  */
1076 static inline void double_rq_lock(struct rq *rq1, struct rq *rq2)
1077         __acquires(rq1->lock)
1078         __acquires(rq2->lock)
1079 {
1080         BUG_ON(!irqs_disabled());
1081         if (rq1 == rq2) {
1082                 raw_spin_lock(&rq1->lock);
1083                 __acquire(rq2->lock);   /* Fake it out ;) */
1084         } else {
1085                 if (rq1 < rq2) {
1086                         raw_spin_lock(&rq1->lock);
1087                         raw_spin_lock_nested(&rq2->lock, SINGLE_DEPTH_NESTING);
1088                 } else {
1089                         raw_spin_lock(&rq2->lock);
1090                         raw_spin_lock_nested(&rq1->lock, SINGLE_DEPTH_NESTING);
1091                 }
1092         }
1093 }
1094 
1095 /*
1096  * double_rq_unlock - safely unlock two runqueues
1097  *
1098  * Note this does not restore interrupts like task_rq_unlock,
1099  * you need to do so manually after calling.
1100  */
1101 static inline void double_rq_unlock(struct rq *rq1, struct rq *rq2)
1102         __releases(rq1->lock)
1103         __releases(rq2->lock)
1104 {
1105         raw_spin_unlock(&rq1->lock);
1106         if (rq1 != rq2)
1107                 raw_spin_unlock(&rq2->lock);
1108         else
1109                 __release(rq2->lock);
1110 }
1111 
1112 #else /* CONFIG_SMP */
1113 
1114 /*
1115  * double_rq_lock - safely lock two runqueues
1116  *
1117  * Note this does not disable interrupts like task_rq_lock,
1118  * you need to do so manually before calling.
1119  */
1120 static inline void double_rq_lock(struct rq *rq1, struct rq *rq2)
1121         __acquires(rq1->lock)
1122         __acquires(rq2->lock)
1123 {
1124         BUG_ON(!irqs_disabled());
1125         BUG_ON(rq1 != rq2);
1126         raw_spin_lock(&rq1->lock);
1127         __acquire(rq2->lock);   /* Fake it out ;) */
1128 }
1129 
1130 /*
1131  * double_rq_unlock - safely unlock two runqueues
1132  *
1133  * Note this does not restore interrupts like task_rq_unlock,
1134  * you need to do so manually after calling.
1135  */
1136 static inline void double_rq_unlock(struct rq *rq1, struct rq *rq2)
1137         __releases(rq1->lock)
1138         __releases(rq2->lock)
1139 {
1140         BUG_ON(rq1 != rq2);
1141         raw_spin_unlock(&rq1->lock);
1142         __release(rq2->lock);
1143 }
1144 
1145 #endif
1146 
1147 extern struct sched_entity *__pick_first_entity(struct cfs_rq *cfs_rq);
1148 extern struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq);
1149 extern void print_cfs_stats(struct seq_file *m, int cpu);
1150 extern void print_rt_stats(struct seq_file *m, int cpu);
1151 
1152 extern void init_cfs_rq(struct cfs_rq *cfs_rq);
1153 extern void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq);
1154 extern void unthrottle_offline_cfs_rqs(struct rq *rq);
1155 
1156 extern void account_cfs_bandwidth_used(int enabled, int was_enabled);
1157 
1158 #ifdef CONFIG_NO_HZ
1159 enum rq_nohz_flag_bits {
1160         NOHZ_TICK_STOPPED,
1161         NOHZ_BALANCE_KICK,
1162         NOHZ_IDLE,
1163 };
1164 
1165 #define nohz_flags(cpu) (&cpu_rq(cpu)->nohz_flags)
1166 #endif
1167 

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