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
  41 /*
  42  * single value that denotes runtime == period, ie unlimited time.
  43  */
  44 #define RUNTIME_INF     ((u64)~0ULL)
  45
  46 static inline int rt_policy(int policy)
  47 {
  48         if (policy == SCHED_FIFO || policy == SCHED_RR)
  49                 return 1;
  50         return 0;
  51 }
  52
  53 static inline int task_has_rt_policy(struct task_struct *p)
  54 {
  55         return rt_policy(p->policy);
  56 }
  57
  58 /*
  59  * This is the priority-queue data structure of the RT scheduling class:
  60  */
  61 struct rt_prio_array {
  62         DECLARE_BITMAP(bitmap, MAX_RT_PRIO+1); /* include 1 bit for delimiter */
  63         struct list_head queue[MAX_RT_PRIO];
  64 };
  65
  66 struct rt_bandwidth {
  67         /* nests inside the rq lock: */
  68         raw_spinlock_t          rt_runtime_lock;
  69         ktime_t                 rt_period;
  70         u64                     rt_runtime;
  71         struct hrtimer          rt_period_timer;
  72 };
  73
  74 extern struct mutex sched_domains_mutex;
  75
  76 #ifdef CONFIG_CGROUP_SCHED
  77
  78 #include <linux/cgroup.h>
  79
  80 struct cfs_rq;
  81 struct rt_rq;
  82
  83 extern struct list_head task_groups;
  84
  85 struct cfs_bandwidth {
  86 #ifdef CONFIG_CFS_BANDWIDTH
  87         raw_spinlock_t lock;
  88         ktime_t period;
  89         u64 quota, runtime;
  90         s64 hierarchal_quota;
  91         u64 runtime_expires;
  92
  93         int idle, timer_active;
  94         struct hrtimer period_timer, slack_timer;
  95         struct list_head throttled_cfs_rq;
  96
  97         /* statistics */
  98         int nr_periods, nr_throttled;
  99         u64 throttled_time;
 100 #endif
 101 };
 102
 103 /* task group related information */
 104 struct task_group {
 105         struct cgroup_subsys_state css;
 106
 107 #ifdef CONFIG_FAIR_GROUP_SCHED
 108         /* schedulable entities of this group on each cpu */
 109         struct sched_entity **se;
 110         /* runqueue "owned" by this group on each cpu */
 111         struct cfs_rq **cfs_rq;
 112         unsigned long shares;
 113
 114         atomic_t load_weight;
 115         atomic64_t load_avg;
 116         atomic_t runnable_avg;
 117 #endif
 118
 119 #ifdef CONFIG_RT_GROUP_SCHED
 120         struct sched_rt_entity **rt_se;
 121         struct rt_rq **rt_rq;
 122
 123         struct rt_bandwidth rt_bandwidth;
 124 #endif
 125
 126         struct rcu_head rcu;
 127         struct list_head list;
 128
 129         struct task_group *parent;
 130         struct list_head siblings;
 131         struct list_head children;
 132
 133 #ifdef CONFIG_SCHED_AUTOGROUP
 134         struct autogroup *autogroup;
 135 #endif
 136
 137         struct cfs_bandwidth cfs_bandwidth;
 138 };
 139
 140 #ifdef CONFIG_FAIR_GROUP_SCHED
 141 #define ROOT_TASK_GROUP_LOAD    NICE_0_LOAD
 142
 143 /*
 144  * A weight of 0 or 1 can cause arithmetics problems.
 145  * A weight of a cfs_rq is the sum of weights of which entities
 146  * are queued on this cfs_rq, so a weight of a entity should not be
 147  * too large, so as the shares value of a task group.
 148  * (The default weight is 1024 - so there's no practical
 149  *  limitation from this.)
 150  */
 151 #define MIN_SHARES      (1UL <<  1)
 152 #define MAX_SHARES      (1UL << 18)
 153 #endif
 154
 155 /* Default task group.
 156  *      Every task in system belong to this group at bootup.
 157  */
 158 extern struct task_group root_task_group;
 159
 160 typedef int (*tg_visitor)(struct task_group *, void *);
 161
 162 extern int walk_tg_tree_from(struct task_group *from,
 163                              tg_visitor down, tg_visitor up, void *data);
 164
 165 /*
 166  * Iterate the full tree, calling @down when first entering a node and @up when
 167  * leaving it for the final time.
 168  *
 169  * Caller must hold rcu_lock or sufficient equivalent.
 170  */
 171 static inline int walk_tg_tree(tg_visitor down, tg_visitor up, void *data)
 172 {
 173         return walk_tg_tree_from(&root_task_group, down, up, data);
 174 }
 175
 176 extern int tg_nop(struct task_group *tg, void *data);
 177
 178 extern void free_fair_sched_group(struct task_group *tg);
 179 extern int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent);
 180 extern void unregister_fair_sched_group(struct task_group *tg, int cpu);
 181 extern void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
 182                         struct sched_entity *se, int cpu,
 183                         struct sched_entity *parent);
 184 extern void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b);
 185 extern int sched_group_set_shares(struct task_group *tg, unsigned long shares);
 186
 187 extern void __refill_cfs_bandwidth_runtime(struct cfs_bandwidth *cfs_b);
 188 extern void __start_cfs_bandwidth(struct cfs_bandwidth *cfs_b);
 189 extern void unthrottle_cfs_rq(struct cfs_rq *cfs_rq);
 190
 191 extern void free_rt_sched_group(struct task_group *tg);
 192 extern int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent);
 193 extern void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
 194                 struct sched_rt_entity *rt_se, int cpu,
 195                 struct sched_rt_entity *parent);
 196
 197 #else /* CONFIG_CGROUP_SCHED */
 198
 199 struct cfs_bandwidth { };
 200
 201 #endif  /* CONFIG_CGROUP_SCHED */
 202
 203 /* CFS-related fields in a runqueue */
 204 struct cfs_rq {
 205         struct load_weight load;
 206         unsigned int nr_running, h_nr_running;
 207
 208         u64 exec_clock;
 209         u64 min_vruntime;
 210 #ifndef CONFIG_64BIT
 211         u64 min_vruntime_copy;
 212 #endif
 213
 214         struct rb_root tasks_timeline;
 215         struct rb_node *rb_leftmost;
 216
 217         /*
 218          * 'curr' points to currently running entity on this cfs_rq.
 219          * It is set to NULL otherwise (i.e when none are currently running).
 220          */
 221         struct sched_entity *curr, *next, *last, *skip;
 222
 223 #ifdef  CONFIG_SCHED_DEBUG
 224         unsigned int nr_spread_over;
 225 #endif
 226
 227 #ifdef CONFIG_SMP
 228 /*
 229  * Load-tracking only depends on SMP, FAIR_GROUP_SCHED dependency below may be
 230  * removed when useful for applications beyond shares distribution (e.g.
 231  * load-balance).
 232  */
 233 #ifdef CONFIG_FAIR_GROUP_SCHED
 234         /*
 235          * CFS Load tracking
 236          * Under CFS, load is tracked on a per-entity basis and aggregated up.
 237          * This allows for the description of both thread and group usage (in
 238          * the FAIR_GROUP_SCHED case).
 239          */
 240         u64 runnable_load_avg, blocked_load_avg;
 241         atomic64_t decay_counter, removed_load;
 242         u64 last_decay;
 243 #endif /* CONFIG_FAIR_GROUP_SCHED */
 244 /* These always depend on CONFIG_FAIR_GROUP_SCHED */
 245 #ifdef CONFIG_FAIR_GROUP_SCHED
 246         u32 tg_runnable_contrib;
 247         u64 tg_load_contrib;
 248 #endif /* CONFIG_FAIR_GROUP_SCHED */
 249
 250         /*
 251          *   h_load = weight * f(tg)
 252          *
 253          * Where f(tg) is the recursive weight fraction assigned to
 254          * this group.
 255          */
 256         unsigned long h_load;
 257 #endif /* CONFIG_SMP */
 258
 259 #ifdef CONFIG_FAIR_GROUP_SCHED
 260         struct rq *rq;  /* cpu runqueue to which this cfs_rq is attached */
 261
 262         /*
 263          * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
 264          * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
 265          * (like users, containers etc.)
 266          *
 267          * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
 268          * list is used during load balance.
 269          */
 270         int on_list;
 271         struct list_head leaf_cfs_rq_list;
 272         struct task_group *tg;  /* group that "owns" this runqueue */
 273
 274 #ifdef CONFIG_CFS_BANDWIDTH
 275         int runtime_enabled;
 276         u64 runtime_expires;
 277         s64 runtime_remaining;
 278
 279         u64 throttled_clock, throttled_clock_task;
 280         u64 throttled_clock_task_time;
 281         int throttled, throttle_count;
 282         struct list_head throttled_list;
 283 #endif /* CONFIG_CFS_BANDWIDTH */
 284 #endif /* CONFIG_FAIR_GROUP_SCHED */
 285 };
 286
 287 static inline int rt_bandwidth_enabled(void)
 288 {
 289         return sysctl_sched_rt_runtime >= 0;
 290 }
 291
 292 /* Real-Time classes' related field in a runqueue: */
 293 struct rt_rq {
 294         struct rt_prio_array active;
 295         unsigned int rt_nr_running;
 296 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
 297         struct {
 298                 int curr; /* highest queued rt task prio */
 299 #ifdef CONFIG_SMP
 300                 int next; /* next highest */
 301 #endif
 302         } highest_prio;
 303 #endif
 304 #ifdef CONFIG_SMP
 305         unsigned long rt_nr_migratory;
 306         unsigned long rt_nr_total;
 307         int overloaded;
 308         struct plist_head pushable_tasks;
 309 #endif
 310         int rt_throttled;
 311         u64 rt_time;
 312         u64 rt_runtime;
 313         /* Nests inside the rq lock: */
 314         raw_spinlock_t rt_runtime_lock;
 315
 316 #ifdef CONFIG_RT_GROUP_SCHED
 317         unsigned long rt_nr_boosted;
 318
 319         struct rq *rq;
 320         struct list_head leaf_rt_rq_list;
 321         struct task_group *tg;
 322 #endif
 323 };
 324
 325 #ifdef CONFIG_SMP
 326
 327 /*
 328  * We add the notion of a root-domain which will be used to define per-domain
 329  * variables. Each exclusive cpuset essentially defines an island domain by
 330  * fully partitioning the member cpus from any other cpuset. Whenever a new
 331  * exclusive cpuset is created, we also create and attach a new root-domain
 332  * object.
 333  *
 334  */
 335 struct root_domain {
 336         atomic_t refcount;
 337         atomic_t rto_count;
 338         struct rcu_head rcu;
 339         cpumask_var_t span;
 340         cpumask_var_t online;
 341
 342         /*
 343          * The "RT overload" flag: it gets set if a CPU has more than
 344          * one runnable RT task.
 345          */
 346         cpumask_var_t rto_mask;
 347         struct cpupri cpupri;
 348 };
 349
 350 extern struct root_domain def_root_domain;
 351
 352 #endif /* CONFIG_SMP */
 353
 354 /*
 355  * This is the main, per-CPU runqueue data structure.
 356  *
 357  * Locking rule: those places that want to lock multiple runqueues
 358  * (such as the load balancing or the thread migration code), lock
 359  * acquire operations must be ordered by ascending &runqueue.
 360  */
 361 struct rq {
 362         /* runqueue lock: */
 363         raw_spinlock_t lock;
 364
 365         /*
 366          * nr_running and cpu_load should be in the same cacheline because
 367          * remote CPUs use both these fields when doing load calculation.
 368          */
 369         unsigned int nr_running;
 370         #define CPU_LOAD_IDX_MAX 5
 371         unsigned long cpu_load[CPU_LOAD_IDX_MAX];
 372         unsigned long last_load_update_tick;
 373 #ifdef CONFIG_NO_HZ
 374         u64 nohz_stamp;
 375         unsigned long nohz_flags;
 376 #endif
 377         int skip_clock_update;
 378
 379         /* capture load from *all* tasks on this cpu: */
 380         struct load_weight load;
 381         unsigned long nr_load_updates;
 382         u64 nr_switches;
 383
 384         struct cfs_rq cfs;
 385         struct rt_rq rt;
 386
 387 #ifdef CONFIG_FAIR_GROUP_SCHED
 388         /* list of leaf cfs_rq on this cpu: */
 389         struct list_head leaf_cfs_rq_list;
 390 #ifdef CONFIG_SMP
 391         unsigned long h_load_throttle;
 392 #endif /* CONFIG_SMP */
 393 #endif /* CONFIG_FAIR_GROUP_SCHED */
 394
 395 #ifdef CONFIG_RT_GROUP_SCHED
 396         struct list_head leaf_rt_rq_list;
 397 #endif
 398
 399         /*
 400          * This is part of a global counter where only the total sum
 401          * over all CPUs matters. A task can increase this counter on
 402          * one CPU and if it got migrated afterwards it may decrease
 403          * it on another CPU. Always updated under the runqueue lock:
 404          */
 405         unsigned long nr_uninterruptible;
 406
 407         struct task_struct *curr, *idle, *stop;
 408         unsigned long next_balance;
 409         struct mm_struct *prev_mm;
 410
 411         u64 clock;
 412         u64 clock_task;
 413
 414         atomic_t nr_iowait;
 415
 416 #ifdef CONFIG_SMP
 417         struct root_domain *rd;
 418         struct sched_domain *sd;
 419
 420         unsigned long cpu_power;
 421
 422         unsigned char idle_balance;
 423         /* For active balancing */
 424         int post_schedule;
 425         int active_balance;
 426         int push_cpu;
 427         struct cpu_stop_work active_balance_work;
 428         /* cpu of this runqueue: */
 429         int cpu;
 430         int online;
 431
 432         struct list_head cfs_tasks;
 433
 434         u64 rt_avg;
 435         u64 age_stamp;
 436         u64 idle_stamp;
 437         u64 avg_idle;
 438 #endif
 439
 440 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
 441         u64 prev_irq_time;
 442 #endif
 443 #ifdef CONFIG_PARAVIRT
 444         u64 prev_steal_time;
 445 #endif
 446 #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
 447         u64 prev_steal_time_rq;
 448 #endif
 449
 450         /* calc_load related fields */
 451         unsigned long calc_load_update;
 452         long calc_load_active;
 453
 454 #ifdef CONFIG_SCHED_HRTICK
 455 #ifdef CONFIG_SMP
 456         int hrtick_csd_pending;
 457         struct call_single_data hrtick_csd;
 458 #endif
 459         struct hrtimer hrtick_timer;
 460 #endif
 461
 462 #ifdef CONFIG_SCHEDSTATS
 463         /* latency stats */
 464         struct sched_info rq_sched_info;
 465         unsigned long long rq_cpu_time;
 466         /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
 467
 468         /* sys_sched_yield() stats */
 469         unsigned int yld_count;
 470
 471         /* schedule() stats */
 472         unsigned int sched_count;
 473         unsigned int sched_goidle;
 474
 475         /* try_to_wake_up() stats */
 476         unsigned int ttwu_count;
 477         unsigned int ttwu_local;
 478 #endif
 479
 480 #ifdef CONFIG_SMP
 481         struct llist_head wake_list;
 482 #endif
 483
 484         struct sched_avg avg;
 485 };
 486
 487 static inline int cpu_of(struct rq *rq)
 488 {
 489 #ifdef CONFIG_SMP
 490         return rq->cpu;
 491 #else
 492         return 0;
 493 #endif
 494 }
 495
 496 DECLARE_PER_CPU(struct rq, runqueues);
 497
 498 #define cpu_rq(cpu)             (&per_cpu(runqueues, (cpu)))
 499 #define this_rq()               (&__get_cpu_var(runqueues))
 500 #define task_rq(p)              cpu_rq(task_cpu(p))
 501 #define cpu_curr(cpu)           (cpu_rq(cpu)->curr)
 502 #define raw_rq()                (&__raw_get_cpu_var(runqueues))
 503
 504 #ifdef CONFIG_SMP
 505
 506 #define rcu_dereference_check_sched_domain(p) \
 507         rcu_dereference_check((p), \
 508                               lockdep_is_held(&sched_domains_mutex))
 509
 510 /*
 511  * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
 512  * See detach_destroy_domains: synchronize_sched for details.
 513  *
 514  * The domain tree of any CPU may only be accessed from within
 515  * preempt-disabled sections.
 516  */
 517 #define for_each_domain(cpu, __sd) \
 518         for (__sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd); \
 519                         __sd; __sd = __sd->parent)
 520
 521 #define for_each_lower_domain(sd) for (; sd; sd = sd->child)
 522
 523 /**
 524  * highest_flag_domain - Return highest sched_domain containing flag.
 525  * @cpu:        The cpu whose highest level of sched domain is to
 526  *              be returned.
 527  * @flag:       The flag to check for the highest sched_domain
 528  *              for the given cpu.
 529  *
 530  * Returns the highest sched_domain of a cpu which contains the given flag.
 531  */
 532 static inline struct sched_domain *highest_flag_domain(int cpu, int flag)
 533 {
 534         struct sched_domain *sd, *hsd = NULL;
 535
 536         for_each_domain(cpu, sd) {
 537                 if (!(sd->flags & flag))
 538                         break;
 539                 hsd = sd;
 540         }
 541
 542         return hsd;
 543 }
 544
 545 DECLARE_PER_CPU(struct sched_domain *, sd_llc);
 546 DECLARE_PER_CPU(int, sd_llc_id);
 547
 548 extern int group_balance_cpu(struct sched_group *sg);
 549
 550 #endif /* CONFIG_SMP */
 551
 552 #include "stats.h"
 553 #include "auto_group.h"
 554
 555 #ifdef CONFIG_CGROUP_SCHED
 556
 557 /*
 558  * Return the group to which this tasks belongs.
 559  *
 560  * We cannot use task_subsys_state() and friends because the cgroup
 561  * subsystem changes that value before the cgroup_subsys::attach() method
 562  * is called, therefore we cannot pin it and might observe the wrong value.
 563  *
 564  * The same is true for autogroup's p->signal->autogroup->tg, the autogroup
 565  * core changes this before calling sched_move_task().
 566  *
 567  * Instead we use a 'copy' which is updated from sched_move_task() while
 568  * holding both task_struct::pi_lock and rq::lock.
 569  */
 570 static inline struct task_group *task_group(struct task_struct *p)
 571 {
 572         return p->sched_task_group;
 573 }
 574
 575 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
 576 static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
 577 {
 578 #if defined(CONFIG_FAIR_GROUP_SCHED) || defined(CONFIG_RT_GROUP_SCHED)
 579         struct task_group *tg = task_group(p);
 580 #endif
 581
 582 #ifdef CONFIG_FAIR_GROUP_SCHED
 583         p->se.cfs_rq = tg->cfs_rq[cpu];
 584         p->se.parent = tg->se[cpu];
 585 #endif
 586
 587 #ifdef CONFIG_RT_GROUP_SCHED
 588         p->rt.rt_rq  = tg->rt_rq[cpu];
 589         p->rt.parent = tg->rt_se[cpu];
 590 #endif
 591 }
 592
 593 #else /* CONFIG_CGROUP_SCHED */
 594
 595 static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { }
 596 static inline struct task_group *task_group(struct task_struct *p)
 597 {
 598         return NULL;
 599 }
 600
 601 #endif /* CONFIG_CGROUP_SCHED */
 602
 603 static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
 604 {
 605         set_task_rq(p, cpu);
 606 #ifdef CONFIG_SMP
 607         /*
 608          * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
 609          * successfuly executed on another CPU. We must ensure that updates of
 610          * per-task data have been completed by this moment.
 611          */
 612         smp_wmb();
 613         task_thread_info(p)->cpu = cpu;
 614 #endif
 615 }
 616
 617 /*
 618  * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
 619  */
 620 #ifdef CONFIG_SCHED_DEBUG
 621 # include <linux/static_key.h>
 622 # define const_debug __read_mostly
 623 #else
 624 # define const_debug const
 625 #endif
 626
 627 extern const_debug unsigned int sysctl_sched_features;
 628
 629 #define SCHED_FEAT(name, enabled)       \
 630         __SCHED_FEAT_##name ,
 631
 632 enum {
 633 #include "features.h"
 634         __SCHED_FEAT_NR,
 635 };
 636
 637 #undef SCHED_FEAT
 638
 639 #if defined(CONFIG_SCHED_DEBUG) && defined(HAVE_JUMP_LABEL)
 640 static __always_inline bool static_branch__true(struct static_key *key)
 641 {
 642         return static_key_true(key); /* Not out of line branch. */
 643 }
 644
 645 static __always_inline bool static_branch__false(struct static_key *key)
 646 {
 647         return static_key_false(key); /* Out of line branch. */
 648 }
 649
 650 #define SCHED_FEAT(name, enabled)                                       \
 651 static __always_inline bool static_branch_##name(struct static_key *key) \
 652 {                                                                       \
 653         return static_branch__##enabled(key);                           \
 654 }
 655
 656 #include "features.h"
 657
 658 #undef SCHED_FEAT
 659
 660 extern struct static_key sched_feat_keys[__SCHED_FEAT_NR];
 661 #define sched_feat(x) (static_branch_##x(&sched_feat_keys[__SCHED_FEAT_##x]))
 662 #else /* !(SCHED_DEBUG && HAVE_JUMP_LABEL) */
 663 #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
 664 #endif /* SCHED_DEBUG && HAVE_JUMP_LABEL */
 665
 666 static inline u64 global_rt_period(void)
 667 {
 668         return (u64)sysctl_sched_rt_period * NSEC_PER_USEC;
 669 }
 670
 671 static inline u64 global_rt_runtime(void)
 672 {
 673         if (sysctl_sched_rt_runtime < 0)
 674                 return RUNTIME_INF;
 675
 676         return (u64)sysctl_sched_rt_runtime * NSEC_PER_USEC;
 677 }
 678
 679
 680
 681 static inline int task_current(struct rq *rq, struct task_struct *p)
 682 {
 683         return rq->curr == p;
 684 }
 685
 686 static inline int task_running(struct rq *rq, struct task_struct *p)
 687 {
 688 #ifdef CONFIG_SMP
 689         return p->on_cpu;
 690 #else
 691         return task_current(rq, p);
 692 #endif
 693 }
 694
 695
 696 #ifndef prepare_arch_switch
 697 # define prepare_arch_switch(next)      do { } while (0)
 698 #endif
 699 #ifndef finish_arch_switch
 700 # define finish_arch_switch(prev)       do { } while (0)
 701 #endif
 702 #ifndef finish_arch_post_lock_switch
 703 # define finish_arch_post_lock_switch() do { } while (0)
 704 #endif
 705
 706 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
 707 static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
 708 {
 709 #ifdef CONFIG_SMP
 710         /*
 711          * We can optimise this out completely for !SMP, because the
 712          * SMP rebalancing from interrupt is the only thing that cares
 713          * here.
 714          */
 715         next->on_cpu = 1;
 716 #endif
 717 }
 718
 719 static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
 720 {
 721 #ifdef CONFIG_SMP
 722         /*
 723          * After ->on_cpu is cleared, the task can be moved to a different CPU.
 724          * We must ensure this doesn't happen until the switch is completely
 725          * finished.
 726          */
 727         smp_wmb();
 728         prev->on_cpu = 0;
 729 #endif
 730 #ifdef CONFIG_DEBUG_SPINLOCK
 731         /* this is a valid case when another task releases the spinlock */
 732         rq->lock.owner = current;
 733 #endif
 734         /*
 735          * If we are tracking spinlock dependencies then we have to
 736          * fix up the runqueue lock - which gets 'carried over' from
 737          * prev into current:
 738          */
 739         spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_);
 740
 741         raw_spin_unlock_irq(&rq->lock);
 742 }
 743
 744 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
 745 static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
 746 {
 747 #ifdef CONFIG_SMP
 748         /*
 749          * We can optimise this out completely for !SMP, because the
 750          * SMP rebalancing from interrupt is the only thing that cares
 751          * here.
 752          */
 753         next->on_cpu = 1;
 754 #endif
 755         raw_spin_unlock(&rq->lock);
 756 }
 757
 758 static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
 759 {
 760 #ifdef CONFIG_SMP
 761         /*
 762          * After ->on_cpu is cleared, the task can be moved to a different CPU.
 763          * We must ensure this doesn't happen until the switch is completely
 764          * finished.
 765          */
 766         smp_wmb();
 767         prev->on_cpu = 0;
 768 #endif
 769         local_irq_enable();
 770 }
 771 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
 772
 773
 774 static inline void update_load_add(struct load_weight *lw, unsigned long inc)
 775 {
 776         lw->weight += inc;
 777         lw->inv_weight = 0;
 778 }
 779
 780 static inline void update_load_sub(struct load_weight *lw, unsigned long dec)
 781 {
 782         lw->weight -= dec;
 783         lw->inv_weight = 0;
 784 }
 785
 786 static inline void update_load_set(struct load_weight *lw, unsigned long w)
 787 {
 788         lw->weight = w;
 789         lw->inv_weight = 0;
 790 }
 791
 792 /*
 793  * To aid in avoiding the subversion of "niceness" due to uneven distribution
 794  * of tasks with abnormal "nice" values across CPUs the contribution that
 795  * each task makes to its run queue's load is weighted according to its
 796  * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
 797  * scaled version of the new time slice allocation that they receive on time
 798  * slice expiry etc.
 799  */
 800
 801 #define WEIGHT_IDLEPRIO                3
 802 #define WMULT_IDLEPRIO         1431655765
 803
 804 /*
 805  * Nice levels are multiplicative, with a gentle 10% change for every
 806  * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
 807  * nice 1, it will get ~10% less CPU time than another CPU-bound task
 808  * that remained on nice 0.
 809  *
 810  * The "10% effect" is relative and cumulative: from _any_ nice level,
 811  * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
 812  * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
 813  * If a task goes up by ~10% and another task goes down by ~10% then
 814  * the relative distance between them is ~25%.)
 815  */
 816 static const int prio_to_weight[40] = {
 817  /* -20 */     88761,     71755,     56483,     46273,     36291,
 818  /* -15 */     29154,     23254,     18705,     14949,     11916,
 819  /* -10 */      9548,      7620,      6100,      4904,      3906,
 820  /*  -5 */      3121,      2501,      1991,      1586,      1277,
 821  /*   0 */      1024,       820,       655,       526,       423,
 822  /*   5 */       335,       272,       215,       172,       137,
 823  /*  10 */       110,        87,        70,        56,        45,
 824  /*  15 */        36,        29,        23,        18,        15,
 825 };
 826
 827 /*
 828  * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
 829  *
 830  * In cases where the weight does not change often, we can use the
 831  * precalculated inverse to speed up arithmetics by turning divisions
 832  * into multiplications:
 833  */
 834 static const u32 prio_to_wmult[40] = {
 835  /* -20 */     48388,     59856,     76040,     92818,    118348,
 836  /* -15 */    147320,    184698,    229616,    287308,    360437,
 837  /* -10 */    449829,    563644,    704093,    875809,   1099582,
 838  /*  -5 */   1376151,   1717300,   2157191,   2708050,   3363326,
 839  /*   0 */   4194304,   5237765,   6557202,   8165337,  10153587,
 840  /*   5 */  12820798,  15790321,  19976592,  24970740,  31350126,
 841  /*  10 */  39045157,  49367440,  61356676,  76695844,  95443717,
 842  /*  15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
 843 };
 844
 845 /* Time spent by the tasks of the cpu accounting group executing in ... */
 846 enum cpuacct_stat_index {
 847         CPUACCT_STAT_USER,      /* ... user mode */
 848         CPUACCT_STAT_SYSTEM,    /* ... kernel mode */
 849
 850         CPUACCT_STAT_NSTATS,
 851 };
 852
 853
 854 #define sched_class_highest (&stop_sched_class)
 855 #define for_each_class(class) \
 856    for (class = sched_class_highest; class; class = class->next)
 857
 858 extern const struct sched_class stop_sched_class;
 859 extern const struct sched_class rt_sched_class;
 860 extern const struct sched_class fair_sched_class;
 861 extern const struct sched_class idle_sched_class;
 862
 863
 864 #ifdef CONFIG_SMP
 865
 866 extern void trigger_load_balance(struct rq *rq, int cpu);
 867 extern void idle_balance(int this_cpu, struct rq *this_rq);
 868
 869 #else   /* CONFIG_SMP */
 870
 871 static inline void idle_balance(int cpu, struct rq *rq)
 872 {
 873 }
 874
 875 #endif
 876
 877 extern void sysrq_sched_debug_show(void);
 878 extern void sched_init_granularity(void);
 879 extern void update_max_interval(void);
 880 extern void update_group_power(struct sched_domain *sd, int cpu);
 881 extern int update_runtime(struct notifier_block *nfb, unsigned long action, void *hcpu);
 882 extern void init_sched_rt_class(void);
 883 extern void init_sched_fair_class(void);
 884
 885 extern void resched_task(struct task_struct *p);
 886 extern void resched_cpu(int cpu);
 887
 888 extern struct rt_bandwidth def_rt_bandwidth;
 889 extern void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime);
 890
 891 extern void update_idle_cpu_load(struct rq *this_rq);
 892
 893 #ifdef CONFIG_CGROUP_CPUACCT
 894 #include <linux/cgroup.h>
 895 /* track cpu usage of a group of tasks and its child groups */
 896 struct cpuacct {
 897         struct cgroup_subsys_state css;
 898         /* cpuusage holds pointer to a u64-type object on every cpu */
 899         u64 __percpu *cpuusage;
 900         struct kernel_cpustat __percpu *cpustat;
 901 };
 902
 903 extern struct cgroup_subsys cpuacct_subsys;
 904 extern struct cpuacct root_cpuacct;
 905
 906 /* return cpu accounting group corresponding to this container */
 907 static inline struct cpuacct *cgroup_ca(struct cgroup *cgrp)
 908 {
 909         return container_of(cgroup_subsys_state(cgrp, cpuacct_subsys_id),
 910                             struct cpuacct, css);
 911 }
 912
 913 /* return cpu accounting group to which this task belongs */
 914 static inline struct cpuacct *task_ca(struct task_struct *tsk)
 915 {
 916         return container_of(task_subsys_state(tsk, cpuacct_subsys_id),
 917                             struct cpuacct, css);
 918 }
 919
 920 static inline struct cpuacct *parent_ca(struct cpuacct *ca)
 921 {
 922         if (!ca || !ca->css.cgroup->parent)
 923                 return NULL;
 924         return cgroup_ca(ca->css.cgroup->parent);
 925 }
 926
 927 extern void cpuacct_charge(struct task_struct *tsk, u64 cputime);
 928 #else
 929 static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}
 930 #endif
 931
 932 #ifdef CONFIG_PARAVIRT
 933 static inline u64 steal_ticks(u64 steal)
 934 {
 935         if (unlikely(steal > NSEC_PER_SEC))
 936                 return div_u64(steal, TICK_NSEC);
 937
 938         return __iter_div_u64_rem(steal, TICK_NSEC, &steal);
 939 }
 940 #endif
 941
 942 static inline void inc_nr_running(struct rq *rq)
 943 {
 944         rq->nr_running++;
 945 }
 946
 947 static inline void dec_nr_running(struct rq *rq)
 948 {
 949         rq->nr_running--;
 950 }
 951
 952 extern void update_rq_clock(struct rq *rq);
 953
 954 extern void activate_task(struct rq *rq, struct task_struct *p, int flags);
 955 extern void deactivate_task(struct rq *rq, struct task_struct *p, int flags);
 956
 957 extern void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags);
 958
 959 extern const_debug unsigned int sysctl_sched_time_avg;
 960 extern const_debug unsigned int sysctl_sched_nr_migrate;
 961 extern const_debug unsigned int sysctl_sched_migration_cost;
 962
 963 static inline u64 sched_avg_period(void)
 964 {
 965         return (u64)sysctl_sched_time_avg * NSEC_PER_MSEC / 2;
 966 }
 967
 968 #ifdef CONFIG_SCHED_HRTICK
 969
 970 /*
 971  * Use hrtick when:
 972  *  - enabled by features
 973  *  - hrtimer is actually high res
 974  */
 975 static inline int hrtick_enabled(struct rq *rq)
 976 {
 977         if (!sched_feat(HRTICK))
 978                 return 0;
 979         if (!cpu_active(cpu_of(rq)))
 980                 return 0;
 981         return hrtimer_is_hres_active(&rq->hrtick_timer);
 982 }
 983
 984 void hrtick_start(struct rq *rq, u64 delay);
 985
 986 #else
 987
 988 static inline int hrtick_enabled(struct rq *rq)
 989 {
 990         return 0;
 991 }
 992
 993 #endif /* CONFIG_SCHED_HRTICK */
 994
 995 #ifdef CONFIG_SMP
 996 extern void sched_avg_update(struct rq *rq);
 997 static inline void sched_rt_avg_update(struct rq *rq, u64 rt_delta)
 998 {
 999         rq->rt_avg += rt_delta;
1000         sched_avg_update(rq);
1001 }
1002 #else
1003 static inline void sched_rt_avg_update(struct rq *rq, u64 rt_delta) { }
1004 static inline void sched_avg_update(struct rq *rq) { }
1005 #endif
1006
1007 extern void start_bandwidth_timer(struct hrtimer *period_timer, ktime_t period);
1008
1009 #ifdef CONFIG_SMP
1010 #ifdef CONFIG_PREEMPT
1011
1012 static inline void double_rq_lock(struct rq *rq1, struct rq *rq2);
1013
1014 /*
1015  * fair double_lock_balance: Safely acquires both rq->locks in a fair
1016  * way at the expense of forcing extra atomic operations in all
1017  * invocations.  This assures that the double_lock is acquired using the
1018  * same underlying policy as the spinlock_t on this architecture, which
1019  * reduces latency compared to the unfair variant below.  However, it
1020  * also adds more overhead and therefore may reduce throughput.
1021  */
1022 static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
1023         __releases(this_rq->lock)
1024         __acquires(busiest->lock)
1025         __acquires(this_rq->lock)
1026 {
1027         raw_spin_unlock(&this_rq->lock);
1028         double_rq_lock(this_rq, busiest);
1029
1030         return 1;
1031 }
1032
1033 #else
1034 /*
1035  * Unfair double_lock_balance: Optimizes throughput at the expense of
1036  * latency by eliminating extra atomic operations when the locks are
1037  * already in proper order on entry.  This favors lower cpu-ids and will
1038  * grant the double lock to lower cpus over higher ids under contention,
1039  * regardless of entry order into the function.
1040  */
1041 static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
1042         __releases(this_rq->lock)
1043         __acquires(busiest->lock)
1044         __acquires(this_rq->lock)
1045 {
1046         int ret = 0;
1047
1048         if (unlikely(!raw_spin_trylock(&busiest->lock))) {
1049                 if (busiest < this_rq) {
1050                         raw_spin_unlock(&this_rq->lock);
1051                         raw_spin_lock(&busiest->lock);
1052                         raw_spin_lock_nested(&this_rq->lock,
1053                                               SINGLE_DEPTH_NESTING);
1054                         ret = 1;
1055                 } else
1056                         raw_spin_lock_nested(&busiest->lock,
1057                                               SINGLE_DEPTH_NESTING);
1058         }
1059         return ret;
1060 }
1061
1062 #endif /* CONFIG_PREEMPT */
1063
1064 /*
1065  * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
1066  */
1067 static inline int double_lock_balance(struct rq *this_rq, struct rq *busiest)
1068 {
1069         if (unlikely(!irqs_disabled())) {
1070                 /* printk() doesn't work good under rq->lock */
1071                 raw_spin_unlock(&this_rq->lock);
1072                 BUG_ON(1);
1073         }
1074
1075         return _double_lock_balance(this_rq, busiest);
1076 }
1077
1078 static inline void double_unlock_balance(struct rq *this_rq, struct rq *busiest)
1079         __releases(busiest->lock)
1080 {
1081         raw_spin_unlock(&busiest->lock);
1082         lock_set_subclass(&this_rq->lock.dep_map, 0, _RET_IP_);
1083 }
1084
1085 /*
1086  * double_rq_lock - safely lock two runqueues
1087  *
1088  * Note this does not disable interrupts like task_rq_lock,
1089  * you need to do so manually before calling.
1090  */
1091 static inline void double_rq_lock(struct rq *rq1, struct rq *rq2)
1092         __acquires(rq1->lock)
1093         __acquires(rq2->lock)
1094 {
1095         BUG_ON(!irqs_disabled());
1096         if (rq1 == rq2) {
1097                 raw_spin_lock(&rq1->lock);
1098                 __acquire(rq2->lock);   /* Fake it out ;) */
1099         } else {
1100                 if (rq1 < rq2) {
1101                         raw_spin_lock(&rq1->lock);
1102                         raw_spin_lock_nested(&rq2->lock, SINGLE_DEPTH_NESTING);
1103                 } else {
1104                         raw_spin_lock(&rq2->lock);
1105                         raw_spin_lock_nested(&rq1->lock, SINGLE_DEPTH_NESTING);
1106                 }
1107         }
1108 }
1109
1110 /*
1111  * double_rq_unlock - safely unlock two runqueues
1112  *
1113  * Note this does not restore interrupts like task_rq_unlock,
1114  * you need to do so manually after calling.
1115  */
1116 static inline void double_rq_unlock(struct rq *rq1, struct rq *rq2)
1117         __releases(rq1->lock)
1118         __releases(rq2->lock)
1119 {
1120         raw_spin_unlock(&rq1->lock);
1121         if (rq1 != rq2)
1122                 raw_spin_unlock(&rq2->lock);
1123         else
1124                 __release(rq2->lock);
1125 }
1126
1127 #else /* CONFIG_SMP */
1128
1129 /*
1130  * double_rq_lock - safely lock two runqueues
1131  *
1132  * Note this does not disable interrupts like task_rq_lock,
1133  * you need to do so manually before calling.
1134  */
1135 static inline void double_rq_lock(struct rq *rq1, struct rq *rq2)
1136         __acquires(rq1->lock)
1137         __acquires(rq2->lock)
1138 {
1139         BUG_ON(!irqs_disabled());
1140         BUG_ON(rq1 != rq2);
1141         raw_spin_lock(&rq1->lock);
1142         __acquire(rq2->lock);   /* Fake it out ;) */
1143 }
1144
1145 /*
1146  * double_rq_unlock - safely unlock two runqueues
1147  *
1148  * Note this does not restore interrupts like task_rq_unlock,
1149  * you need to do so manually after calling.
1150  */
1151 static inline void double_rq_unlock(struct rq *rq1, struct rq *rq2)
1152         __releases(rq1->lock)
1153         __releases(rq2->lock)
1154 {
1155         BUG_ON(rq1 != rq2);
1156         raw_spin_unlock(&rq1->lock);
1157         __release(rq2->lock);
1158 }
1159
1160 #endif
1161
1162 extern struct sched_entity *__pick_first_entity(struct cfs_rq *cfs_rq);
1163 extern struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq);
1164 extern void print_cfs_stats(struct seq_file *m, int cpu);
1165 extern void print_rt_stats(struct seq_file *m, int cpu);
1166
1167 extern void init_cfs_rq(struct cfs_rq *cfs_rq);
1168 extern void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq);
1169
1170 extern void account_cfs_bandwidth_used(int enabled, int was_enabled);
1171
1172 #ifdef CONFIG_NO_HZ
1173 enum rq_nohz_flag_bits {
1174         NOHZ_TICK_STOPPED,
1175         NOHZ_BALANCE_KICK,
1176         NOHZ_IDLE,
1177 };
1178
1179 #define nohz_flags(cpu) (&cpu_rq(cpu)->nohz_flags)
1180 #endif
1181
1182 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
1183
1184 DECLARE_PER_CPU(u64, cpu_hardirq_time);
1185 DECLARE_PER_CPU(u64, cpu_softirq_time);
1186
1187 #ifndef CONFIG_64BIT
1188 DECLARE_PER_CPU(seqcount_t, irq_time_seq);
1189
1190 static inline void irq_time_write_begin(void)
1191 {
1192         __this_cpu_inc(irq_time_seq.sequence);
1193         smp_wmb();
1194 }
1195
1196 static inline void irq_time_write_end(void)
1197 {
1198         smp_wmb();
1199         __this_cpu_inc(irq_time_seq.sequence);
1200 }
1201
1202 static inline u64 irq_time_read(int cpu)
1203 {
1204         u64 irq_time;
1205         unsigned seq;
1206
1207         do {
1208                 seq = read_seqcount_begin(&per_cpu(irq_time_seq, cpu));
1209                 irq_time = per_cpu(cpu_softirq_time, cpu) +
1210                            per_cpu(cpu_hardirq_time, cpu);
1211         } while (read_seqcount_retry(&per_cpu(irq_time_seq, cpu), seq));
1212
1213         return irq_time;
1214 }
1215 #else /* CONFIG_64BIT */
1216 static inline void irq_time_write_begin(void)
1217 {
1218 }
1219
1220 static inline void irq_time_write_end(void)
1221 {
1222 }
1223
1224 static inline u64 irq_time_read(int cpu)
1225 {
1226         return per_cpu(cpu_softirq_time, cpu) + per_cpu(cpu_hardirq_time, cpu);
1227 }
1228 #endif /* CONFIG_64BIT */
1229 #endif /* CONFIG_IRQ_TIME_ACCOUNTING */