sched.c 217 KB

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  1. /*
  2. * kernel/sched.c
  3. *
  4. * Kernel scheduler and related syscalls
  5. *
  6. * Copyright (C) 1991-2002 Linus Torvalds
  7. *
  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
  11. * by Andrea Arcangeli
  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
  22. * by Peter Williams
  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
  27. */
  28. #include <linux/mm.h>
  29. #include <linux/module.h>
  30. #include <linux/nmi.h>
  31. #include <linux/init.h>
  32. #include <linux/uaccess.h>
  33. #include <linux/highmem.h>
  34. #include <linux/smp_lock.h>
  35. #include <asm/mmu_context.h>
  36. #include <linux/interrupt.h>
  37. #include <linux/capability.h>
  38. #include <linux/completion.h>
  39. #include <linux/kernel_stat.h>
  40. #include <linux/debug_locks.h>
  41. #include <linux/perf_event.h>
  42. #include <linux/security.h>
  43. #include <linux/notifier.h>
  44. #include <linux/profile.h>
  45. #include <linux/freezer.h>
  46. #include <linux/vmalloc.h>
  47. #include <linux/blkdev.h>
  48. #include <linux/delay.h>
  49. #include <linux/pid_namespace.h>
  50. #include <linux/smp.h>
  51. #include <linux/threads.h>
  52. #include <linux/timer.h>
  53. #include <linux/rcupdate.h>
  54. #include <linux/cpu.h>
  55. #include <linux/cpuset.h>
  56. #include <linux/percpu.h>
  57. #include <linux/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/unistd.h>
  67. #include <linux/pagemap.h>
  68. #include <linux/hrtimer.h>
  69. #include <linux/tick.h>
  70. #include <linux/debugfs.h>
  71. #include <linux/ctype.h>
  72. #include <linux/ftrace.h>
  73. #include <asm/tlb.h>
  74. #include <asm/irq_regs.h>
  75. #include "sched_cpupri.h"
  76. #define CREATE_TRACE_POINTS
  77. #include <trace/events/sched.h>
  78. /*
  79. * Convert user-nice values [ -20 ... 0 ... 19 ]
  80. * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
  81. * and back.
  82. */
  83. #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
  84. #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
  85. #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
  86. /*
  87. * 'User priority' is the nice value converted to something we
  88. * can work with better when scaling various scheduler parameters,
  89. * it's a [ 0 ... 39 ] range.
  90. */
  91. #define USER_PRIO(p) ((p)-MAX_RT_PRIO)
  92. #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
  93. #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
  94. /*
  95. * Helpers for converting nanosecond timing to jiffy resolution
  96. */
  97. #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
  98. #define NICE_0_LOAD SCHED_LOAD_SCALE
  99. #define NICE_0_SHIFT SCHED_LOAD_SHIFT
  100. /*
  101. * These are the 'tuning knobs' of the scheduler:
  102. *
  103. * default timeslice is 100 msecs (used only for SCHED_RR tasks).
  104. * Timeslices get refilled after they expire.
  105. */
  106. #define DEF_TIMESLICE (100 * HZ / 1000)
  107. /*
  108. * single value that denotes runtime == period, ie unlimited time.
  109. */
  110. #define RUNTIME_INF ((u64)~0ULL)
  111. static inline int rt_policy(int policy)
  112. {
  113. if (unlikely(policy == SCHED_FIFO || policy == SCHED_RR))
  114. return 1;
  115. return 0;
  116. }
  117. static inline int task_has_rt_policy(struct task_struct *p)
  118. {
  119. return rt_policy(p->policy);
  120. }
  121. /*
  122. * This is the priority-queue data structure of the RT scheduling class:
  123. */
  124. struct rt_prio_array {
  125. DECLARE_BITMAP(bitmap, MAX_RT_PRIO+1); /* include 1 bit for delimiter */
  126. struct list_head queue[MAX_RT_PRIO];
  127. };
  128. struct rt_bandwidth {
  129. /* nests inside the rq lock: */
  130. raw_spinlock_t rt_runtime_lock;
  131. ktime_t rt_period;
  132. u64 rt_runtime;
  133. struct hrtimer rt_period_timer;
  134. };
  135. static struct rt_bandwidth def_rt_bandwidth;
  136. static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun);
  137. static enum hrtimer_restart sched_rt_period_timer(struct hrtimer *timer)
  138. {
  139. struct rt_bandwidth *rt_b =
  140. container_of(timer, struct rt_bandwidth, rt_period_timer);
  141. ktime_t now;
  142. int overrun;
  143. int idle = 0;
  144. for (;;) {
  145. now = hrtimer_cb_get_time(timer);
  146. overrun = hrtimer_forward(timer, now, rt_b->rt_period);
  147. if (!overrun)
  148. break;
  149. idle = do_sched_rt_period_timer(rt_b, overrun);
  150. }
  151. return idle ? HRTIMER_NORESTART : HRTIMER_RESTART;
  152. }
  153. static
  154. void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime)
  155. {
  156. rt_b->rt_period = ns_to_ktime(period);
  157. rt_b->rt_runtime = runtime;
  158. raw_spin_lock_init(&rt_b->rt_runtime_lock);
  159. hrtimer_init(&rt_b->rt_period_timer,
  160. CLOCK_MONOTONIC, HRTIMER_MODE_REL);
  161. rt_b->rt_period_timer.function = sched_rt_period_timer;
  162. }
  163. static inline int rt_bandwidth_enabled(void)
  164. {
  165. return sysctl_sched_rt_runtime >= 0;
  166. }
  167. static void start_rt_bandwidth(struct rt_bandwidth *rt_b)
  168. {
  169. ktime_t now;
  170. if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)
  171. return;
  172. if (hrtimer_active(&rt_b->rt_period_timer))
  173. return;
  174. raw_spin_lock(&rt_b->rt_runtime_lock);
  175. for (;;) {
  176. unsigned long delta;
  177. ktime_t soft, hard;
  178. if (hrtimer_active(&rt_b->rt_period_timer))
  179. break;
  180. now = hrtimer_cb_get_time(&rt_b->rt_period_timer);
  181. hrtimer_forward(&rt_b->rt_period_timer, now, rt_b->rt_period);
  182. soft = hrtimer_get_softexpires(&rt_b->rt_period_timer);
  183. hard = hrtimer_get_expires(&rt_b->rt_period_timer);
  184. delta = ktime_to_ns(ktime_sub(hard, soft));
  185. __hrtimer_start_range_ns(&rt_b->rt_period_timer, soft, delta,
  186. HRTIMER_MODE_ABS_PINNED, 0);
  187. }
  188. raw_spin_unlock(&rt_b->rt_runtime_lock);
  189. }
  190. #ifdef CONFIG_RT_GROUP_SCHED
  191. static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b)
  192. {
  193. hrtimer_cancel(&rt_b->rt_period_timer);
  194. }
  195. #endif
  196. /*
  197. * sched_domains_mutex serializes calls to arch_init_sched_domains,
  198. * detach_destroy_domains and partition_sched_domains.
  199. */
  200. static DEFINE_MUTEX(sched_domains_mutex);
  201. #ifdef CONFIG_CGROUP_SCHED
  202. #include <linux/cgroup.h>
  203. struct cfs_rq;
  204. static LIST_HEAD(task_groups);
  205. /* task group related information */
  206. struct task_group {
  207. struct cgroup_subsys_state css;
  208. #ifdef CONFIG_FAIR_GROUP_SCHED
  209. /* schedulable entities of this group on each cpu */
  210. struct sched_entity **se;
  211. /* runqueue "owned" by this group on each cpu */
  212. struct cfs_rq **cfs_rq;
  213. unsigned long shares;
  214. #endif
  215. #ifdef CONFIG_RT_GROUP_SCHED
  216. struct sched_rt_entity **rt_se;
  217. struct rt_rq **rt_rq;
  218. struct rt_bandwidth rt_bandwidth;
  219. #endif
  220. struct rcu_head rcu;
  221. struct list_head list;
  222. struct task_group *parent;
  223. struct list_head siblings;
  224. struct list_head children;
  225. };
  226. #define root_task_group init_task_group
  227. /* task_group_lock serializes add/remove of task groups and also changes to
  228. * a task group's cpu shares.
  229. */
  230. static DEFINE_SPINLOCK(task_group_lock);
  231. #ifdef CONFIG_FAIR_GROUP_SCHED
  232. #ifdef CONFIG_SMP
  233. static int root_task_group_empty(void)
  234. {
  235. return list_empty(&root_task_group.children);
  236. }
  237. #endif
  238. # define INIT_TASK_GROUP_LOAD NICE_0_LOAD
  239. /*
  240. * A weight of 0 or 1 can cause arithmetics problems.
  241. * A weight of a cfs_rq is the sum of weights of which entities
  242. * are queued on this cfs_rq, so a weight of a entity should not be
  243. * too large, so as the shares value of a task group.
  244. * (The default weight is 1024 - so there's no practical
  245. * limitation from this.)
  246. */
  247. #define MIN_SHARES 2
  248. #define MAX_SHARES (1UL << 18)
  249. static int init_task_group_load = INIT_TASK_GROUP_LOAD;
  250. #endif
  251. /* Default task group.
  252. * Every task in system belong to this group at bootup.
  253. */
  254. struct task_group init_task_group;
  255. /* return group to which a task belongs */
  256. static inline struct task_group *task_group(struct task_struct *p)
  257. {
  258. struct task_group *tg;
  259. #ifdef CONFIG_CGROUP_SCHED
  260. tg = container_of(task_subsys_state(p, cpu_cgroup_subsys_id),
  261. struct task_group, css);
  262. #else
  263. tg = &init_task_group;
  264. #endif
  265. return tg;
  266. }
  267. /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
  268. static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
  269. {
  270. #ifdef CONFIG_FAIR_GROUP_SCHED
  271. p->se.cfs_rq = task_group(p)->cfs_rq[cpu];
  272. p->se.parent = task_group(p)->se[cpu];
  273. #endif
  274. #ifdef CONFIG_RT_GROUP_SCHED
  275. p->rt.rt_rq = task_group(p)->rt_rq[cpu];
  276. p->rt.parent = task_group(p)->rt_se[cpu];
  277. #endif
  278. }
  279. #else
  280. static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { }
  281. static inline struct task_group *task_group(struct task_struct *p)
  282. {
  283. return NULL;
  284. }
  285. #endif /* CONFIG_CGROUP_SCHED */
  286. /* CFS-related fields in a runqueue */
  287. struct cfs_rq {
  288. struct load_weight load;
  289. unsigned long nr_running;
  290. u64 exec_clock;
  291. u64 min_vruntime;
  292. struct rb_root tasks_timeline;
  293. struct rb_node *rb_leftmost;
  294. struct list_head tasks;
  295. struct list_head *balance_iterator;
  296. /*
  297. * 'curr' points to currently running entity on this cfs_rq.
  298. * It is set to NULL otherwise (i.e when none are currently running).
  299. */
  300. struct sched_entity *curr, *next, *last;
  301. unsigned int nr_spread_over;
  302. #ifdef CONFIG_FAIR_GROUP_SCHED
  303. struct rq *rq; /* cpu runqueue to which this cfs_rq is attached */
  304. /*
  305. * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
  306. * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
  307. * (like users, containers etc.)
  308. *
  309. * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
  310. * list is used during load balance.
  311. */
  312. struct list_head leaf_cfs_rq_list;
  313. struct task_group *tg; /* group that "owns" this runqueue */
  314. #ifdef CONFIG_SMP
  315. /*
  316. * the part of load.weight contributed by tasks
  317. */
  318. unsigned long task_weight;
  319. /*
  320. * h_load = weight * f(tg)
  321. *
  322. * Where f(tg) is the recursive weight fraction assigned to
  323. * this group.
  324. */
  325. unsigned long h_load;
  326. /*
  327. * this cpu's part of tg->shares
  328. */
  329. unsigned long shares;
  330. /*
  331. * load.weight at the time we set shares
  332. */
  333. unsigned long rq_weight;
  334. #endif
  335. #endif
  336. };
  337. /* Real-Time classes' related field in a runqueue: */
  338. struct rt_rq {
  339. struct rt_prio_array active;
  340. unsigned long rt_nr_running;
  341. #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
  342. struct {
  343. int curr; /* highest queued rt task prio */
  344. #ifdef CONFIG_SMP
  345. int next; /* next highest */
  346. #endif
  347. } highest_prio;
  348. #endif
  349. #ifdef CONFIG_SMP
  350. unsigned long rt_nr_migratory;
  351. unsigned long rt_nr_total;
  352. int overloaded;
  353. struct plist_head pushable_tasks;
  354. #endif
  355. int rt_throttled;
  356. u64 rt_time;
  357. u64 rt_runtime;
  358. /* Nests inside the rq lock: */
  359. raw_spinlock_t rt_runtime_lock;
  360. #ifdef CONFIG_RT_GROUP_SCHED
  361. unsigned long rt_nr_boosted;
  362. struct rq *rq;
  363. struct list_head leaf_rt_rq_list;
  364. struct task_group *tg;
  365. #endif
  366. };
  367. #ifdef CONFIG_SMP
  368. /*
  369. * We add the notion of a root-domain which will be used to define per-domain
  370. * variables. Each exclusive cpuset essentially defines an island domain by
  371. * fully partitioning the member cpus from any other cpuset. Whenever a new
  372. * exclusive cpuset is created, we also create and attach a new root-domain
  373. * object.
  374. *
  375. */
  376. struct root_domain {
  377. atomic_t refcount;
  378. cpumask_var_t span;
  379. cpumask_var_t online;
  380. /*
  381. * The "RT overload" flag: it gets set if a CPU has more than
  382. * one runnable RT task.
  383. */
  384. cpumask_var_t rto_mask;
  385. atomic_t rto_count;
  386. #ifdef CONFIG_SMP
  387. struct cpupri cpupri;
  388. #endif
  389. };
  390. /*
  391. * By default the system creates a single root-domain with all cpus as
  392. * members (mimicking the global state we have today).
  393. */
  394. static struct root_domain def_root_domain;
  395. #endif
  396. /*
  397. * This is the main, per-CPU runqueue data structure.
  398. *
  399. * Locking rule: those places that want to lock multiple runqueues
  400. * (such as the load balancing or the thread migration code), lock
  401. * acquire operations must be ordered by ascending &runqueue.
  402. */
  403. struct rq {
  404. /* runqueue lock: */
  405. raw_spinlock_t lock;
  406. /*
  407. * nr_running and cpu_load should be in the same cacheline because
  408. * remote CPUs use both these fields when doing load calculation.
  409. */
  410. unsigned long nr_running;
  411. #define CPU_LOAD_IDX_MAX 5
  412. unsigned long cpu_load[CPU_LOAD_IDX_MAX];
  413. #ifdef CONFIG_NO_HZ
  414. u64 nohz_stamp;
  415. unsigned char in_nohz_recently;
  416. #endif
  417. unsigned int skip_clock_update;
  418. /* capture load from *all* tasks on this cpu: */
  419. struct load_weight load;
  420. unsigned long nr_load_updates;
  421. u64 nr_switches;
  422. struct cfs_rq cfs;
  423. struct rt_rq rt;
  424. #ifdef CONFIG_FAIR_GROUP_SCHED
  425. /* list of leaf cfs_rq on this cpu: */
  426. struct list_head leaf_cfs_rq_list;
  427. #endif
  428. #ifdef CONFIG_RT_GROUP_SCHED
  429. struct list_head leaf_rt_rq_list;
  430. #endif
  431. /*
  432. * This is part of a global counter where only the total sum
  433. * over all CPUs matters. A task can increase this counter on
  434. * one CPU and if it got migrated afterwards it may decrease
  435. * it on another CPU. Always updated under the runqueue lock:
  436. */
  437. unsigned long nr_uninterruptible;
  438. struct task_struct *curr, *idle;
  439. unsigned long next_balance;
  440. struct mm_struct *prev_mm;
  441. u64 clock;
  442. atomic_t nr_iowait;
  443. #ifdef CONFIG_SMP
  444. struct root_domain *rd;
  445. struct sched_domain *sd;
  446. unsigned char idle_at_tick;
  447. /* For active balancing */
  448. int post_schedule;
  449. int active_balance;
  450. int push_cpu;
  451. /* cpu of this runqueue: */
  452. int cpu;
  453. int online;
  454. unsigned long avg_load_per_task;
  455. struct task_struct *migration_thread;
  456. struct list_head migration_queue;
  457. u64 rt_avg;
  458. u64 age_stamp;
  459. u64 idle_stamp;
  460. u64 avg_idle;
  461. #endif
  462. /* calc_load related fields */
  463. unsigned long calc_load_update;
  464. long calc_load_active;
  465. #ifdef CONFIG_SCHED_HRTICK
  466. #ifdef CONFIG_SMP
  467. int hrtick_csd_pending;
  468. struct call_single_data hrtick_csd;
  469. #endif
  470. struct hrtimer hrtick_timer;
  471. #endif
  472. #ifdef CONFIG_SCHEDSTATS
  473. /* latency stats */
  474. struct sched_info rq_sched_info;
  475. unsigned long long rq_cpu_time;
  476. /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
  477. /* sys_sched_yield() stats */
  478. unsigned int yld_count;
  479. /* schedule() stats */
  480. unsigned int sched_switch;
  481. unsigned int sched_count;
  482. unsigned int sched_goidle;
  483. /* try_to_wake_up() stats */
  484. unsigned int ttwu_count;
  485. unsigned int ttwu_local;
  486. /* BKL stats */
  487. unsigned int bkl_count;
  488. #endif
  489. };
  490. static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
  491. static inline
  492. void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags)
  493. {
  494. rq->curr->sched_class->check_preempt_curr(rq, p, flags);
  495. /*
  496. * A queue event has occurred, and we're going to schedule. In
  497. * this case, we can save a useless back to back clock update.
  498. */
  499. if (test_tsk_need_resched(p))
  500. rq->skip_clock_update = 1;
  501. }
  502. static inline int cpu_of(struct rq *rq)
  503. {
  504. #ifdef CONFIG_SMP
  505. return rq->cpu;
  506. #else
  507. return 0;
  508. #endif
  509. }
  510. #define rcu_dereference_check_sched_domain(p) \
  511. rcu_dereference_check((p), \
  512. rcu_read_lock_sched_held() || \
  513. lockdep_is_held(&sched_domains_mutex))
  514. /*
  515. * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
  516. * See detach_destroy_domains: synchronize_sched for details.
  517. *
  518. * The domain tree of any CPU may only be accessed from within
  519. * preempt-disabled sections.
  520. */
  521. #define for_each_domain(cpu, __sd) \
  522. for (__sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
  523. #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
  524. #define this_rq() (&__get_cpu_var(runqueues))
  525. #define task_rq(p) cpu_rq(task_cpu(p))
  526. #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
  527. #define raw_rq() (&__raw_get_cpu_var(runqueues))
  528. inline void update_rq_clock(struct rq *rq)
  529. {
  530. if (!rq->skip_clock_update)
  531. rq->clock = sched_clock_cpu(cpu_of(rq));
  532. }
  533. /*
  534. * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
  535. */
  536. #ifdef CONFIG_SCHED_DEBUG
  537. # define const_debug __read_mostly
  538. #else
  539. # define const_debug static const
  540. #endif
  541. /**
  542. * runqueue_is_locked
  543. * @cpu: the processor in question.
  544. *
  545. * Returns true if the current cpu runqueue is locked.
  546. * This interface allows printk to be called with the runqueue lock
  547. * held and know whether or not it is OK to wake up the klogd.
  548. */
  549. int runqueue_is_locked(int cpu)
  550. {
  551. return raw_spin_is_locked(&cpu_rq(cpu)->lock);
  552. }
  553. /*
  554. * Debugging: various feature bits
  555. */
  556. #define SCHED_FEAT(name, enabled) \
  557. __SCHED_FEAT_##name ,
  558. enum {
  559. #include "sched_features.h"
  560. };
  561. #undef SCHED_FEAT
  562. #define SCHED_FEAT(name, enabled) \
  563. (1UL << __SCHED_FEAT_##name) * enabled |
  564. const_debug unsigned int sysctl_sched_features =
  565. #include "sched_features.h"
  566. 0;
  567. #undef SCHED_FEAT
  568. #ifdef CONFIG_SCHED_DEBUG
  569. #define SCHED_FEAT(name, enabled) \
  570. #name ,
  571. static __read_mostly char *sched_feat_names[] = {
  572. #include "sched_features.h"
  573. NULL
  574. };
  575. #undef SCHED_FEAT
  576. static int sched_feat_show(struct seq_file *m, void *v)
  577. {
  578. int i;
  579. for (i = 0; sched_feat_names[i]; i++) {
  580. if (!(sysctl_sched_features & (1UL << i)))
  581. seq_puts(m, "NO_");
  582. seq_printf(m, "%s ", sched_feat_names[i]);
  583. }
  584. seq_puts(m, "\n");
  585. return 0;
  586. }
  587. static ssize_t
  588. sched_feat_write(struct file *filp, const char __user *ubuf,
  589. size_t cnt, loff_t *ppos)
  590. {
  591. char buf[64];
  592. char *cmp = buf;
  593. int neg = 0;
  594. int i;
  595. if (cnt > 63)
  596. cnt = 63;
  597. if (copy_from_user(&buf, ubuf, cnt))
  598. return -EFAULT;
  599. buf[cnt] = 0;
  600. if (strncmp(buf, "NO_", 3) == 0) {
  601. neg = 1;
  602. cmp += 3;
  603. }
  604. for (i = 0; sched_feat_names[i]; i++) {
  605. int len = strlen(sched_feat_names[i]);
  606. if (strncmp(cmp, sched_feat_names[i], len) == 0) {
  607. if (neg)
  608. sysctl_sched_features &= ~(1UL << i);
  609. else
  610. sysctl_sched_features |= (1UL << i);
  611. break;
  612. }
  613. }
  614. if (!sched_feat_names[i])
  615. return -EINVAL;
  616. *ppos += cnt;
  617. return cnt;
  618. }
  619. static int sched_feat_open(struct inode *inode, struct file *filp)
  620. {
  621. return single_open(filp, sched_feat_show, NULL);
  622. }
  623. static const struct file_operations sched_feat_fops = {
  624. .open = sched_feat_open,
  625. .write = sched_feat_write,
  626. .read = seq_read,
  627. .llseek = seq_lseek,
  628. .release = single_release,
  629. };
  630. static __init int sched_init_debug(void)
  631. {
  632. debugfs_create_file("sched_features", 0644, NULL, NULL,
  633. &sched_feat_fops);
  634. return 0;
  635. }
  636. late_initcall(sched_init_debug);
  637. #endif
  638. #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
  639. /*
  640. * Number of tasks to iterate in a single balance run.
  641. * Limited because this is done with IRQs disabled.
  642. */
  643. const_debug unsigned int sysctl_sched_nr_migrate = 32;
  644. /*
  645. * ratelimit for updating the group shares.
  646. * default: 0.25ms
  647. */
  648. unsigned int sysctl_sched_shares_ratelimit = 250000;
  649. unsigned int normalized_sysctl_sched_shares_ratelimit = 250000;
  650. /*
  651. * Inject some fuzzyness into changing the per-cpu group shares
  652. * this avoids remote rq-locks at the expense of fairness.
  653. * default: 4
  654. */
  655. unsigned int sysctl_sched_shares_thresh = 4;
  656. /*
  657. * period over which we average the RT time consumption, measured
  658. * in ms.
  659. *
  660. * default: 1s
  661. */
  662. const_debug unsigned int sysctl_sched_time_avg = MSEC_PER_SEC;
  663. /*
  664. * period over which we measure -rt task cpu usage in us.
  665. * default: 1s
  666. */
  667. unsigned int sysctl_sched_rt_period = 1000000;
  668. static __read_mostly int scheduler_running;
  669. /*
  670. * part of the period that we allow rt tasks to run in us.
  671. * default: 0.95s
  672. */
  673. int sysctl_sched_rt_runtime = 950000;
  674. static inline u64 global_rt_period(void)
  675. {
  676. return (u64)sysctl_sched_rt_period * NSEC_PER_USEC;
  677. }
  678. static inline u64 global_rt_runtime(void)
  679. {
  680. if (sysctl_sched_rt_runtime < 0)
  681. return RUNTIME_INF;
  682. return (u64)sysctl_sched_rt_runtime * NSEC_PER_USEC;
  683. }
  684. #ifndef prepare_arch_switch
  685. # define prepare_arch_switch(next) do { } while (0)
  686. #endif
  687. #ifndef finish_arch_switch
  688. # define finish_arch_switch(prev) do { } while (0)
  689. #endif
  690. static inline int task_current(struct rq *rq, struct task_struct *p)
  691. {
  692. return rq->curr == p;
  693. }
  694. #ifndef __ARCH_WANT_UNLOCKED_CTXSW
  695. static inline int task_running(struct rq *rq, struct task_struct *p)
  696. {
  697. return task_current(rq, p);
  698. }
  699. static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
  700. {
  701. }
  702. static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
  703. {
  704. #ifdef CONFIG_DEBUG_SPINLOCK
  705. /* this is a valid case when another task releases the spinlock */
  706. rq->lock.owner = current;
  707. #endif
  708. /*
  709. * If we are tracking spinlock dependencies then we have to
  710. * fix up the runqueue lock - which gets 'carried over' from
  711. * prev into current:
  712. */
  713. spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_);
  714. raw_spin_unlock_irq(&rq->lock);
  715. }
  716. #else /* __ARCH_WANT_UNLOCKED_CTXSW */
  717. static inline int task_running(struct rq *rq, struct task_struct *p)
  718. {
  719. #ifdef CONFIG_SMP
  720. return p->oncpu;
  721. #else
  722. return task_current(rq, p);
  723. #endif
  724. }
  725. static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
  726. {
  727. #ifdef CONFIG_SMP
  728. /*
  729. * We can optimise this out completely for !SMP, because the
  730. * SMP rebalancing from interrupt is the only thing that cares
  731. * here.
  732. */
  733. next->oncpu = 1;
  734. #endif
  735. #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
  736. raw_spin_unlock_irq(&rq->lock);
  737. #else
  738. raw_spin_unlock(&rq->lock);
  739. #endif
  740. }
  741. static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
  742. {
  743. #ifdef CONFIG_SMP
  744. /*
  745. * After ->oncpu is cleared, the task can be moved to a different CPU.
  746. * We must ensure this doesn't happen until the switch is completely
  747. * finished.
  748. */
  749. smp_wmb();
  750. prev->oncpu = 0;
  751. #endif
  752. #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
  753. local_irq_enable();
  754. #endif
  755. }
  756. #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
  757. /*
  758. * Check whether the task is waking, we use this to synchronize against
  759. * ttwu() so that task_cpu() reports a stable number.
  760. *
  761. * We need to make an exception for PF_STARTING tasks because the fork
  762. * path might require task_rq_lock() to work, eg. it can call
  763. * set_cpus_allowed_ptr() from the cpuset clone_ns code.
  764. */
  765. static inline int task_is_waking(struct task_struct *p)
  766. {
  767. return unlikely((p->state == TASK_WAKING) && !(p->flags & PF_STARTING));
  768. }
  769. /*
  770. * __task_rq_lock - lock the runqueue a given task resides on.
  771. * Must be called interrupts disabled.
  772. */
  773. static inline struct rq *__task_rq_lock(struct task_struct *p)
  774. __acquires(rq->lock)
  775. {
  776. struct rq *rq;
  777. for (;;) {
  778. while (task_is_waking(p))
  779. cpu_relax();
  780. rq = task_rq(p);
  781. raw_spin_lock(&rq->lock);
  782. if (likely(rq == task_rq(p) && !task_is_waking(p)))
  783. return rq;
  784. raw_spin_unlock(&rq->lock);
  785. }
  786. }
  787. /*
  788. * task_rq_lock - lock the runqueue a given task resides on and disable
  789. * interrupts. Note the ordering: we can safely lookup the task_rq without
  790. * explicitly disabling preemption.
  791. */
  792. static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags)
  793. __acquires(rq->lock)
  794. {
  795. struct rq *rq;
  796. for (;;) {
  797. while (task_is_waking(p))
  798. cpu_relax();
  799. local_irq_save(*flags);
  800. rq = task_rq(p);
  801. raw_spin_lock(&rq->lock);
  802. if (likely(rq == task_rq(p) && !task_is_waking(p)))
  803. return rq;
  804. raw_spin_unlock_irqrestore(&rq->lock, *flags);
  805. }
  806. }
  807. void task_rq_unlock_wait(struct task_struct *p)
  808. {
  809. struct rq *rq = task_rq(p);
  810. smp_mb(); /* spin-unlock-wait is not a full memory barrier */
  811. raw_spin_unlock_wait(&rq->lock);
  812. }
  813. static void __task_rq_unlock(struct rq *rq)
  814. __releases(rq->lock)
  815. {
  816. raw_spin_unlock(&rq->lock);
  817. }
  818. static inline void task_rq_unlock(struct rq *rq, unsigned long *flags)
  819. __releases(rq->lock)
  820. {
  821. raw_spin_unlock_irqrestore(&rq->lock, *flags);
  822. }
  823. /*
  824. * this_rq_lock - lock this runqueue and disable interrupts.
  825. */
  826. static struct rq *this_rq_lock(void)
  827. __acquires(rq->lock)
  828. {
  829. struct rq *rq;
  830. local_irq_disable();
  831. rq = this_rq();
  832. raw_spin_lock(&rq->lock);
  833. return rq;
  834. }
  835. #ifdef CONFIG_SCHED_HRTICK
  836. /*
  837. * Use HR-timers to deliver accurate preemption points.
  838. *
  839. * Its all a bit involved since we cannot program an hrt while holding the
  840. * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
  841. * reschedule event.
  842. *
  843. * When we get rescheduled we reprogram the hrtick_timer outside of the
  844. * rq->lock.
  845. */
  846. /*
  847. * Use hrtick when:
  848. * - enabled by features
  849. * - hrtimer is actually high res
  850. */
  851. static inline int hrtick_enabled(struct rq *rq)
  852. {
  853. if (!sched_feat(HRTICK))
  854. return 0;
  855. if (!cpu_active(cpu_of(rq)))
  856. return 0;
  857. return hrtimer_is_hres_active(&rq->hrtick_timer);
  858. }
  859. static void hrtick_clear(struct rq *rq)
  860. {
  861. if (hrtimer_active(&rq->hrtick_timer))
  862. hrtimer_cancel(&rq->hrtick_timer);
  863. }
  864. /*
  865. * High-resolution timer tick.
  866. * Runs from hardirq context with interrupts disabled.
  867. */
  868. static enum hrtimer_restart hrtick(struct hrtimer *timer)
  869. {
  870. struct rq *rq = container_of(timer, struct rq, hrtick_timer);
  871. WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
  872. raw_spin_lock(&rq->lock);
  873. update_rq_clock(rq);
  874. rq->curr->sched_class->task_tick(rq, rq->curr, 1);
  875. raw_spin_unlock(&rq->lock);
  876. return HRTIMER_NORESTART;
  877. }
  878. #ifdef CONFIG_SMP
  879. /*
  880. * called from hardirq (IPI) context
  881. */
  882. static void __hrtick_start(void *arg)
  883. {
  884. struct rq *rq = arg;
  885. raw_spin_lock(&rq->lock);
  886. hrtimer_restart(&rq->hrtick_timer);
  887. rq->hrtick_csd_pending = 0;
  888. raw_spin_unlock(&rq->lock);
  889. }
  890. /*
  891. * Called to set the hrtick timer state.
  892. *
  893. * called with rq->lock held and irqs disabled
  894. */
  895. static void hrtick_start(struct rq *rq, u64 delay)
  896. {
  897. struct hrtimer *timer = &rq->hrtick_timer;
  898. ktime_t time = ktime_add_ns(timer->base->get_time(), delay);
  899. hrtimer_set_expires(timer, time);
  900. if (rq == this_rq()) {
  901. hrtimer_restart(timer);
  902. } else if (!rq->hrtick_csd_pending) {
  903. __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd, 0);
  904. rq->hrtick_csd_pending = 1;
  905. }
  906. }
  907. static int
  908. hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu)
  909. {
  910. int cpu = (int)(long)hcpu;
  911. switch (action) {
  912. case CPU_UP_CANCELED:
  913. case CPU_UP_CANCELED_FROZEN:
  914. case CPU_DOWN_PREPARE:
  915. case CPU_DOWN_PREPARE_FROZEN:
  916. case CPU_DEAD:
  917. case CPU_DEAD_FROZEN:
  918. hrtick_clear(cpu_rq(cpu));
  919. return NOTIFY_OK;
  920. }
  921. return NOTIFY_DONE;
  922. }
  923. static __init void init_hrtick(void)
  924. {
  925. hotcpu_notifier(hotplug_hrtick, 0);
  926. }
  927. #else
  928. /*
  929. * Called to set the hrtick timer state.
  930. *
  931. * called with rq->lock held and irqs disabled
  932. */
  933. static void hrtick_start(struct rq *rq, u64 delay)
  934. {
  935. __hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0,
  936. HRTIMER_MODE_REL_PINNED, 0);
  937. }
  938. static inline void init_hrtick(void)
  939. {
  940. }
  941. #endif /* CONFIG_SMP */
  942. static void init_rq_hrtick(struct rq *rq)
  943. {
  944. #ifdef CONFIG_SMP
  945. rq->hrtick_csd_pending = 0;
  946. rq->hrtick_csd.flags = 0;
  947. rq->hrtick_csd.func = __hrtick_start;
  948. rq->hrtick_csd.info = rq;
  949. #endif
  950. hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
  951. rq->hrtick_timer.function = hrtick;
  952. }
  953. #else /* CONFIG_SCHED_HRTICK */
  954. static inline void hrtick_clear(struct rq *rq)
  955. {
  956. }
  957. static inline void init_rq_hrtick(struct rq *rq)
  958. {
  959. }
  960. static inline void init_hrtick(void)
  961. {
  962. }
  963. #endif /* CONFIG_SCHED_HRTICK */
  964. /*
  965. * resched_task - mark a task 'to be rescheduled now'.
  966. *
  967. * On UP this means the setting of the need_resched flag, on SMP it
  968. * might also involve a cross-CPU call to trigger the scheduler on
  969. * the target CPU.
  970. */
  971. #ifdef CONFIG_SMP
  972. #ifndef tsk_is_polling
  973. #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
  974. #endif
  975. static void resched_task(struct task_struct *p)
  976. {
  977. int cpu;
  978. assert_raw_spin_locked(&task_rq(p)->lock);
  979. if (test_tsk_need_resched(p))
  980. return;
  981. set_tsk_need_resched(p);
  982. cpu = task_cpu(p);
  983. if (cpu == smp_processor_id())
  984. return;
  985. /* NEED_RESCHED must be visible before we test polling */
  986. smp_mb();
  987. if (!tsk_is_polling(p))
  988. smp_send_reschedule(cpu);
  989. }
  990. static void resched_cpu(int cpu)
  991. {
  992. struct rq *rq = cpu_rq(cpu);
  993. unsigned long flags;
  994. if (!raw_spin_trylock_irqsave(&rq->lock, flags))
  995. return;
  996. resched_task(cpu_curr(cpu));
  997. raw_spin_unlock_irqrestore(&rq->lock, flags);
  998. }
  999. #ifdef CONFIG_NO_HZ
  1000. /*
  1001. * When add_timer_on() enqueues a timer into the timer wheel of an
  1002. * idle CPU then this timer might expire before the next timer event
  1003. * which is scheduled to wake up that CPU. In case of a completely
  1004. * idle system the next event might even be infinite time into the
  1005. * future. wake_up_idle_cpu() ensures that the CPU is woken up and
  1006. * leaves the inner idle loop so the newly added timer is taken into
  1007. * account when the CPU goes back to idle and evaluates the timer
  1008. * wheel for the next timer event.
  1009. */
  1010. void wake_up_idle_cpu(int cpu)
  1011. {
  1012. struct rq *rq = cpu_rq(cpu);
  1013. if (cpu == smp_processor_id())
  1014. return;
  1015. /*
  1016. * This is safe, as this function is called with the timer
  1017. * wheel base lock of (cpu) held. When the CPU is on the way
  1018. * to idle and has not yet set rq->curr to idle then it will
  1019. * be serialized on the timer wheel base lock and take the new
  1020. * timer into account automatically.
  1021. */
  1022. if (rq->curr != rq->idle)
  1023. return;
  1024. /*
  1025. * We can set TIF_RESCHED on the idle task of the other CPU
  1026. * lockless. The worst case is that the other CPU runs the
  1027. * idle task through an additional NOOP schedule()
  1028. */
  1029. set_tsk_need_resched(rq->idle);
  1030. /* NEED_RESCHED must be visible before we test polling */
  1031. smp_mb();
  1032. if (!tsk_is_polling(rq->idle))
  1033. smp_send_reschedule(cpu);
  1034. }
  1035. int nohz_ratelimit(int cpu)
  1036. {
  1037. struct rq *rq = cpu_rq(cpu);
  1038. u64 diff = rq->clock - rq->nohz_stamp;
  1039. rq->nohz_stamp = rq->clock;
  1040. return diff < (NSEC_PER_SEC / HZ) >> 1;
  1041. }
  1042. #endif /* CONFIG_NO_HZ */
  1043. static u64 sched_avg_period(void)
  1044. {
  1045. return (u64)sysctl_sched_time_avg * NSEC_PER_MSEC / 2;
  1046. }
  1047. static void sched_avg_update(struct rq *rq)
  1048. {
  1049. s64 period = sched_avg_period();
  1050. while ((s64)(rq->clock - rq->age_stamp) > period) {
  1051. rq->age_stamp += period;
  1052. rq->rt_avg /= 2;
  1053. }
  1054. }
  1055. static void sched_rt_avg_update(struct rq *rq, u64 rt_delta)
  1056. {
  1057. rq->rt_avg += rt_delta;
  1058. sched_avg_update(rq);
  1059. }
  1060. #else /* !CONFIG_SMP */
  1061. static void resched_task(struct task_struct *p)
  1062. {
  1063. assert_raw_spin_locked(&task_rq(p)->lock);
  1064. set_tsk_need_resched(p);
  1065. }
  1066. static void sched_rt_avg_update(struct rq *rq, u64 rt_delta)
  1067. {
  1068. }
  1069. #endif /* CONFIG_SMP */
  1070. #if BITS_PER_LONG == 32
  1071. # define WMULT_CONST (~0UL)
  1072. #else
  1073. # define WMULT_CONST (1UL << 32)
  1074. #endif
  1075. #define WMULT_SHIFT 32
  1076. /*
  1077. * Shift right and round:
  1078. */
  1079. #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
  1080. /*
  1081. * delta *= weight / lw
  1082. */
  1083. static unsigned long
  1084. calc_delta_mine(unsigned long delta_exec, unsigned long weight,
  1085. struct load_weight *lw)
  1086. {
  1087. u64 tmp;
  1088. if (!lw->inv_weight) {
  1089. if (BITS_PER_LONG > 32 && unlikely(lw->weight >= WMULT_CONST))
  1090. lw->inv_weight = 1;
  1091. else
  1092. lw->inv_weight = 1 + (WMULT_CONST-lw->weight/2)
  1093. / (lw->weight+1);
  1094. }
  1095. tmp = (u64)delta_exec * weight;
  1096. /*
  1097. * Check whether we'd overflow the 64-bit multiplication:
  1098. */
  1099. if (unlikely(tmp > WMULT_CONST))
  1100. tmp = SRR(SRR(tmp, WMULT_SHIFT/2) * lw->inv_weight,
  1101. WMULT_SHIFT/2);
  1102. else
  1103. tmp = SRR(tmp * lw->inv_weight, WMULT_SHIFT);
  1104. return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX);
  1105. }
  1106. static inline void update_load_add(struct load_weight *lw, unsigned long inc)
  1107. {
  1108. lw->weight += inc;
  1109. lw->inv_weight = 0;
  1110. }
  1111. static inline void update_load_sub(struct load_weight *lw, unsigned long dec)
  1112. {
  1113. lw->weight -= dec;
  1114. lw->inv_weight = 0;
  1115. }
  1116. /*
  1117. * To aid in avoiding the subversion of "niceness" due to uneven distribution
  1118. * of tasks with abnormal "nice" values across CPUs the contribution that
  1119. * each task makes to its run queue's load is weighted according to its
  1120. * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
  1121. * scaled version of the new time slice allocation that they receive on time
  1122. * slice expiry etc.
  1123. */
  1124. #define WEIGHT_IDLEPRIO 3
  1125. #define WMULT_IDLEPRIO 1431655765
  1126. /*
  1127. * Nice levels are multiplicative, with a gentle 10% change for every
  1128. * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
  1129. * nice 1, it will get ~10% less CPU time than another CPU-bound task
  1130. * that remained on nice 0.
  1131. *
  1132. * The "10% effect" is relative and cumulative: from _any_ nice level,
  1133. * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
  1134. * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
  1135. * If a task goes up by ~10% and another task goes down by ~10% then
  1136. * the relative distance between them is ~25%.)
  1137. */
  1138. static const int prio_to_weight[40] = {
  1139. /* -20 */ 88761, 71755, 56483, 46273, 36291,
  1140. /* -15 */ 29154, 23254, 18705, 14949, 11916,
  1141. /* -10 */ 9548, 7620, 6100, 4904, 3906,
  1142. /* -5 */ 3121, 2501, 1991, 1586, 1277,
  1143. /* 0 */ 1024, 820, 655, 526, 423,
  1144. /* 5 */ 335, 272, 215, 172, 137,
  1145. /* 10 */ 110, 87, 70, 56, 45,
  1146. /* 15 */ 36, 29, 23, 18, 15,
  1147. };
  1148. /*
  1149. * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
  1150. *
  1151. * In cases where the weight does not change often, we can use the
  1152. * precalculated inverse to speed up arithmetics by turning divisions
  1153. * into multiplications:
  1154. */
  1155. static const u32 prio_to_wmult[40] = {
  1156. /* -20 */ 48388, 59856, 76040, 92818, 118348,
  1157. /* -15 */ 147320, 184698, 229616, 287308, 360437,
  1158. /* -10 */ 449829, 563644, 704093, 875809, 1099582,
  1159. /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
  1160. /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
  1161. /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
  1162. /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
  1163. /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
  1164. };
  1165. /* Time spent by the tasks of the cpu accounting group executing in ... */
  1166. enum cpuacct_stat_index {
  1167. CPUACCT_STAT_USER, /* ... user mode */
  1168. CPUACCT_STAT_SYSTEM, /* ... kernel mode */
  1169. CPUACCT_STAT_NSTATS,
  1170. };
  1171. #ifdef CONFIG_CGROUP_CPUACCT
  1172. static void cpuacct_charge(struct task_struct *tsk, u64 cputime);
  1173. static void cpuacct_update_stats(struct task_struct *tsk,
  1174. enum cpuacct_stat_index idx, cputime_t val);
  1175. #else
  1176. static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}
  1177. static inline void cpuacct_update_stats(struct task_struct *tsk,
  1178. enum cpuacct_stat_index idx, cputime_t val) {}
  1179. #endif
  1180. static inline void inc_cpu_load(struct rq *rq, unsigned long load)
  1181. {
  1182. update_load_add(&rq->load, load);
  1183. }
  1184. static inline void dec_cpu_load(struct rq *rq, unsigned long load)
  1185. {
  1186. update_load_sub(&rq->load, load);
  1187. }
  1188. #if (defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)) || defined(CONFIG_RT_GROUP_SCHED)
  1189. typedef int (*tg_visitor)(struct task_group *, void *);
  1190. /*
  1191. * Iterate the full tree, calling @down when first entering a node and @up when
  1192. * leaving it for the final time.
  1193. */
  1194. static int walk_tg_tree(tg_visitor down, tg_visitor up, void *data)
  1195. {
  1196. struct task_group *parent, *child;
  1197. int ret;
  1198. rcu_read_lock();
  1199. parent = &root_task_group;
  1200. down:
  1201. ret = (*down)(parent, data);
  1202. if (ret)
  1203. goto out_unlock;
  1204. list_for_each_entry_rcu(child, &parent->children, siblings) {
  1205. parent = child;
  1206. goto down;
  1207. up:
  1208. continue;
  1209. }
  1210. ret = (*up)(parent, data);
  1211. if (ret)
  1212. goto out_unlock;
  1213. child = parent;
  1214. parent = parent->parent;
  1215. if (parent)
  1216. goto up;
  1217. out_unlock:
  1218. rcu_read_unlock();
  1219. return ret;
  1220. }
  1221. static int tg_nop(struct task_group *tg, void *data)
  1222. {
  1223. return 0;
  1224. }
  1225. #endif
  1226. #ifdef CONFIG_SMP
  1227. /* Used instead of source_load when we know the type == 0 */
  1228. static unsigned long weighted_cpuload(const int cpu)
  1229. {
  1230. return cpu_rq(cpu)->load.weight;
  1231. }
  1232. /*
  1233. * Return a low guess at the load of a migration-source cpu weighted
  1234. * according to the scheduling class and "nice" value.
  1235. *
  1236. * We want to under-estimate the load of migration sources, to
  1237. * balance conservatively.
  1238. */
  1239. static unsigned long source_load(int cpu, int type)
  1240. {
  1241. struct rq *rq = cpu_rq(cpu);
  1242. unsigned long total = weighted_cpuload(cpu);
  1243. if (type == 0 || !sched_feat(LB_BIAS))
  1244. return total;
  1245. return min(rq->cpu_load[type-1], total);
  1246. }
  1247. /*
  1248. * Return a high guess at the load of a migration-target cpu weighted
  1249. * according to the scheduling class and "nice" value.
  1250. */
  1251. static unsigned long target_load(int cpu, int type)
  1252. {
  1253. struct rq *rq = cpu_rq(cpu);
  1254. unsigned long total = weighted_cpuload(cpu);
  1255. if (type == 0 || !sched_feat(LB_BIAS))
  1256. return total;
  1257. return max(rq->cpu_load[type-1], total);
  1258. }
  1259. static struct sched_group *group_of(int cpu)
  1260. {
  1261. struct sched_domain *sd = rcu_dereference_sched(cpu_rq(cpu)->sd);
  1262. if (!sd)
  1263. return NULL;
  1264. return sd->groups;
  1265. }
  1266. static unsigned long power_of(int cpu)
  1267. {
  1268. struct sched_group *group = group_of(cpu);
  1269. if (!group)
  1270. return SCHED_LOAD_SCALE;
  1271. return group->cpu_power;
  1272. }
  1273. static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd);
  1274. static unsigned long cpu_avg_load_per_task(int cpu)
  1275. {
  1276. struct rq *rq = cpu_rq(cpu);
  1277. unsigned long nr_running = ACCESS_ONCE(rq->nr_running);
  1278. if (nr_running)
  1279. rq->avg_load_per_task = rq->load.weight / nr_running;
  1280. else
  1281. rq->avg_load_per_task = 0;
  1282. return rq->avg_load_per_task;
  1283. }
  1284. #ifdef CONFIG_FAIR_GROUP_SCHED
  1285. static __read_mostly unsigned long *update_shares_data;
  1286. static void __set_se_shares(struct sched_entity *se, unsigned long shares);
  1287. /*
  1288. * Calculate and set the cpu's group shares.
  1289. */
  1290. static void update_group_shares_cpu(struct task_group *tg, int cpu,
  1291. unsigned long sd_shares,
  1292. unsigned long sd_rq_weight,
  1293. unsigned long *usd_rq_weight)
  1294. {
  1295. unsigned long shares, rq_weight;
  1296. int boost = 0;
  1297. rq_weight = usd_rq_weight[cpu];
  1298. if (!rq_weight) {
  1299. boost = 1;
  1300. rq_weight = NICE_0_LOAD;
  1301. }
  1302. /*
  1303. * \Sum_j shares_j * rq_weight_i
  1304. * shares_i = -----------------------------
  1305. * \Sum_j rq_weight_j
  1306. */
  1307. shares = (sd_shares * rq_weight) / sd_rq_weight;
  1308. shares = clamp_t(unsigned long, shares, MIN_SHARES, MAX_SHARES);
  1309. if (abs(shares - tg->se[cpu]->load.weight) >
  1310. sysctl_sched_shares_thresh) {
  1311. struct rq *rq = cpu_rq(cpu);
  1312. unsigned long flags;
  1313. raw_spin_lock_irqsave(&rq->lock, flags);
  1314. tg->cfs_rq[cpu]->rq_weight = boost ? 0 : rq_weight;
  1315. tg->cfs_rq[cpu]->shares = boost ? 0 : shares;
  1316. __set_se_shares(tg->se[cpu], shares);
  1317. raw_spin_unlock_irqrestore(&rq->lock, flags);
  1318. }
  1319. }
  1320. /*
  1321. * Re-compute the task group their per cpu shares over the given domain.
  1322. * This needs to be done in a bottom-up fashion because the rq weight of a
  1323. * parent group depends on the shares of its child groups.
  1324. */
  1325. static int tg_shares_up(struct task_group *tg, void *data)
  1326. {
  1327. unsigned long weight, rq_weight = 0, sum_weight = 0, shares = 0;
  1328. unsigned long *usd_rq_weight;
  1329. struct sched_domain *sd = data;
  1330. unsigned long flags;
  1331. int i;
  1332. if (!tg->se[0])
  1333. return 0;
  1334. local_irq_save(flags);
  1335. usd_rq_weight = per_cpu_ptr(update_shares_data, smp_processor_id());
  1336. for_each_cpu(i, sched_domain_span(sd)) {
  1337. weight = tg->cfs_rq[i]->load.weight;
  1338. usd_rq_weight[i] = weight;
  1339. rq_weight += weight;
  1340. /*
  1341. * If there are currently no tasks on the cpu pretend there
  1342. * is one of average load so that when a new task gets to
  1343. * run here it will not get delayed by group starvation.
  1344. */
  1345. if (!weight)
  1346. weight = NICE_0_LOAD;
  1347. sum_weight += weight;
  1348. shares += tg->cfs_rq[i]->shares;
  1349. }
  1350. if (!rq_weight)
  1351. rq_weight = sum_weight;
  1352. if ((!shares && rq_weight) || shares > tg->shares)
  1353. shares = tg->shares;
  1354. if (!sd->parent || !(sd->parent->flags & SD_LOAD_BALANCE))
  1355. shares = tg->shares;
  1356. for_each_cpu(i, sched_domain_span(sd))
  1357. update_group_shares_cpu(tg, i, shares, rq_weight, usd_rq_weight);
  1358. local_irq_restore(flags);
  1359. return 0;
  1360. }
  1361. /*
  1362. * Compute the cpu's hierarchical load factor for each task group.
  1363. * This needs to be done in a top-down fashion because the load of a child
  1364. * group is a fraction of its parents load.
  1365. */
  1366. static int tg_load_down(struct task_group *tg, void *data)
  1367. {
  1368. unsigned long load;
  1369. long cpu = (long)data;
  1370. if (!tg->parent) {
  1371. load = cpu_rq(cpu)->load.weight;
  1372. } else {
  1373. load = tg->parent->cfs_rq[cpu]->h_load;
  1374. load *= tg->cfs_rq[cpu]->shares;
  1375. load /= tg->parent->cfs_rq[cpu]->load.weight + 1;
  1376. }
  1377. tg->cfs_rq[cpu]->h_load = load;
  1378. return 0;
  1379. }
  1380. static void update_shares(struct sched_domain *sd)
  1381. {
  1382. s64 elapsed;
  1383. u64 now;
  1384. if (root_task_group_empty())
  1385. return;
  1386. now = cpu_clock(raw_smp_processor_id());
  1387. elapsed = now - sd->last_update;
  1388. if (elapsed >= (s64)(u64)sysctl_sched_shares_ratelimit) {
  1389. sd->last_update = now;
  1390. walk_tg_tree(tg_nop, tg_shares_up, sd);
  1391. }
  1392. }
  1393. static void update_h_load(long cpu)
  1394. {
  1395. if (root_task_group_empty())
  1396. return;
  1397. walk_tg_tree(tg_load_down, tg_nop, (void *)cpu);
  1398. }
  1399. #else
  1400. static inline void update_shares(struct sched_domain *sd)
  1401. {
  1402. }
  1403. #endif
  1404. #ifdef CONFIG_PREEMPT
  1405. static void double_rq_lock(struct rq *rq1, struct rq *rq2);
  1406. /*
  1407. * fair double_lock_balance: Safely acquires both rq->locks in a fair
  1408. * way at the expense of forcing extra atomic operations in all
  1409. * invocations. This assures that the double_lock is acquired using the
  1410. * same underlying policy as the spinlock_t on this architecture, which
  1411. * reduces latency compared to the unfair variant below. However, it
  1412. * also adds more overhead and therefore may reduce throughput.
  1413. */
  1414. static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
  1415. __releases(this_rq->lock)
  1416. __acquires(busiest->lock)
  1417. __acquires(this_rq->lock)
  1418. {
  1419. raw_spin_unlock(&this_rq->lock);
  1420. double_rq_lock(this_rq, busiest);
  1421. return 1;
  1422. }
  1423. #else
  1424. /*
  1425. * Unfair double_lock_balance: Optimizes throughput at the expense of
  1426. * latency by eliminating extra atomic operations when the locks are
  1427. * already in proper order on entry. This favors lower cpu-ids and will
  1428. * grant the double lock to lower cpus over higher ids under contention,
  1429. * regardless of entry order into the function.
  1430. */
  1431. static int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
  1432. __releases(this_rq->lock)
  1433. __acquires(busiest->lock)
  1434. __acquires(this_rq->lock)
  1435. {
  1436. int ret = 0;
  1437. if (unlikely(!raw_spin_trylock(&busiest->lock))) {
  1438. if (busiest < this_rq) {
  1439. raw_spin_unlock(&this_rq->lock);
  1440. raw_spin_lock(&busiest->lock);
  1441. raw_spin_lock_nested(&this_rq->lock,
  1442. SINGLE_DEPTH_NESTING);
  1443. ret = 1;
  1444. } else
  1445. raw_spin_lock_nested(&busiest->lock,
  1446. SINGLE_DEPTH_NESTING);
  1447. }
  1448. return ret;
  1449. }
  1450. #endif /* CONFIG_PREEMPT */
  1451. /*
  1452. * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
  1453. */
  1454. static int double_lock_balance(struct rq *this_rq, struct rq *busiest)
  1455. {
  1456. if (unlikely(!irqs_disabled())) {
  1457. /* printk() doesn't work good under rq->lock */
  1458. raw_spin_unlock(&this_rq->lock);
  1459. BUG_ON(1);
  1460. }
  1461. return _double_lock_balance(this_rq, busiest);
  1462. }
  1463. static inline void double_unlock_balance(struct rq *this_rq, struct rq *busiest)
  1464. __releases(busiest->lock)
  1465. {
  1466. raw_spin_unlock(&busiest->lock);
  1467. lock_set_subclass(&this_rq->lock.dep_map, 0, _RET_IP_);
  1468. }
  1469. /*
  1470. * double_rq_lock - safely lock two runqueues
  1471. *
  1472. * Note this does not disable interrupts like task_rq_lock,
  1473. * you need to do so manually before calling.
  1474. */
  1475. static void double_rq_lock(struct rq *rq1, struct rq *rq2)
  1476. __acquires(rq1->lock)
  1477. __acquires(rq2->lock)
  1478. {
  1479. BUG_ON(!irqs_disabled());
  1480. if (rq1 == rq2) {
  1481. raw_spin_lock(&rq1->lock);
  1482. __acquire(rq2->lock); /* Fake it out ;) */
  1483. } else {
  1484. if (rq1 < rq2) {
  1485. raw_spin_lock(&rq1->lock);
  1486. raw_spin_lock_nested(&rq2->lock, SINGLE_DEPTH_NESTING);
  1487. } else {
  1488. raw_spin_lock(&rq2->lock);
  1489. raw_spin_lock_nested(&rq1->lock, SINGLE_DEPTH_NESTING);
  1490. }
  1491. }
  1492. }
  1493. /*
  1494. * double_rq_unlock - safely unlock two runqueues
  1495. *
  1496. * Note this does not restore interrupts like task_rq_unlock,
  1497. * you need to do so manually after calling.
  1498. */
  1499. static void double_rq_unlock(struct rq *rq1, struct rq *rq2)
  1500. __releases(rq1->lock)
  1501. __releases(rq2->lock)
  1502. {
  1503. raw_spin_unlock(&rq1->lock);
  1504. if (rq1 != rq2)
  1505. raw_spin_unlock(&rq2->lock);
  1506. else
  1507. __release(rq2->lock);
  1508. }
  1509. #endif
  1510. #ifdef CONFIG_FAIR_GROUP_SCHED
  1511. static void cfs_rq_set_shares(struct cfs_rq *cfs_rq, unsigned long shares)
  1512. {
  1513. #ifdef CONFIG_SMP
  1514. cfs_rq->shares = shares;
  1515. #endif
  1516. }
  1517. #endif
  1518. static void calc_load_account_active(struct rq *this_rq);
  1519. static void update_sysctl(void);
  1520. static int get_update_sysctl_factor(void);
  1521. static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
  1522. {
  1523. set_task_rq(p, cpu);
  1524. #ifdef CONFIG_SMP
  1525. /*
  1526. * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
  1527. * successfuly executed on another CPU. We must ensure that updates of
  1528. * per-task data have been completed by this moment.
  1529. */
  1530. smp_wmb();
  1531. task_thread_info(p)->cpu = cpu;
  1532. #endif
  1533. }
  1534. static const struct sched_class rt_sched_class;
  1535. #define sched_class_highest (&rt_sched_class)
  1536. #define for_each_class(class) \
  1537. for (class = sched_class_highest; class; class = class->next)
  1538. #include "sched_stats.h"
  1539. static void inc_nr_running(struct rq *rq)
  1540. {
  1541. rq->nr_running++;
  1542. }
  1543. static void dec_nr_running(struct rq *rq)
  1544. {
  1545. rq->nr_running--;
  1546. }
  1547. static void set_load_weight(struct task_struct *p)
  1548. {
  1549. if (task_has_rt_policy(p)) {
  1550. p->se.load.weight = prio_to_weight[0] * 2;
  1551. p->se.load.inv_weight = prio_to_wmult[0] >> 1;
  1552. return;
  1553. }
  1554. /*
  1555. * SCHED_IDLE tasks get minimal weight:
  1556. */
  1557. if (p->policy == SCHED_IDLE) {
  1558. p->se.load.weight = WEIGHT_IDLEPRIO;
  1559. p->se.load.inv_weight = WMULT_IDLEPRIO;
  1560. return;
  1561. }
  1562. p->se.load.weight = prio_to_weight[p->static_prio - MAX_RT_PRIO];
  1563. p->se.load.inv_weight = prio_to_wmult[p->static_prio - MAX_RT_PRIO];
  1564. }
  1565. static void update_avg(u64 *avg, u64 sample)
  1566. {
  1567. s64 diff = sample - *avg;
  1568. *avg += diff >> 3;
  1569. }
  1570. static void
  1571. enqueue_task(struct rq *rq, struct task_struct *p, int wakeup, bool head)
  1572. {
  1573. update_rq_clock(rq);
  1574. sched_info_queued(p);
  1575. p->sched_class->enqueue_task(rq, p, wakeup, head);
  1576. p->se.on_rq = 1;
  1577. }
  1578. static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep)
  1579. {
  1580. update_rq_clock(rq);
  1581. sched_info_dequeued(p);
  1582. p->sched_class->dequeue_task(rq, p, sleep);
  1583. p->se.on_rq = 0;
  1584. }
  1585. /*
  1586. * activate_task - move a task to the runqueue.
  1587. */
  1588. static void activate_task(struct rq *rq, struct task_struct *p, int wakeup)
  1589. {
  1590. if (task_contributes_to_load(p))
  1591. rq->nr_uninterruptible--;
  1592. enqueue_task(rq, p, wakeup, false);
  1593. inc_nr_running(rq);
  1594. }
  1595. /*
  1596. * deactivate_task - remove a task from the runqueue.
  1597. */
  1598. static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep)
  1599. {
  1600. if (task_contributes_to_load(p))
  1601. rq->nr_uninterruptible++;
  1602. dequeue_task(rq, p, sleep);
  1603. dec_nr_running(rq);
  1604. }
  1605. #include "sched_idletask.c"
  1606. #include "sched_fair.c"
  1607. #include "sched_rt.c"
  1608. #ifdef CONFIG_SCHED_DEBUG
  1609. # include "sched_debug.c"
  1610. #endif
  1611. /*
  1612. * __normal_prio - return the priority that is based on the static prio
  1613. */
  1614. static inline int __normal_prio(struct task_struct *p)
  1615. {
  1616. return p->static_prio;
  1617. }
  1618. /*
  1619. * Calculate the expected normal priority: i.e. priority
  1620. * without taking RT-inheritance into account. Might be
  1621. * boosted by interactivity modifiers. Changes upon fork,
  1622. * setprio syscalls, and whenever the interactivity
  1623. * estimator recalculates.
  1624. */
  1625. static inline int normal_prio(struct task_struct *p)
  1626. {
  1627. int prio;
  1628. if (task_has_rt_policy(p))
  1629. prio = MAX_RT_PRIO-1 - p->rt_priority;
  1630. else
  1631. prio = __normal_prio(p);
  1632. return prio;
  1633. }
  1634. /*
  1635. * Calculate the current priority, i.e. the priority
  1636. * taken into account by the scheduler. This value might
  1637. * be boosted by RT tasks, or might be boosted by
  1638. * interactivity modifiers. Will be RT if the task got
  1639. * RT-boosted. If not then it returns p->normal_prio.
  1640. */
  1641. static int effective_prio(struct task_struct *p)
  1642. {
  1643. p->normal_prio = normal_prio(p);
  1644. /*
  1645. * If we are RT tasks or we were boosted to RT priority,
  1646. * keep the priority unchanged. Otherwise, update priority
  1647. * to the normal priority:
  1648. */
  1649. if (!rt_prio(p->prio))
  1650. return p->normal_prio;
  1651. return p->prio;
  1652. }
  1653. /**
  1654. * task_curr - is this task currently executing on a CPU?
  1655. * @p: the task in question.
  1656. */
  1657. inline int task_curr(const struct task_struct *p)
  1658. {
  1659. return cpu_curr(task_cpu(p)) == p;
  1660. }
  1661. static inline void check_class_changed(struct rq *rq, struct task_struct *p,
  1662. const struct sched_class *prev_class,
  1663. int oldprio, int running)
  1664. {
  1665. if (prev_class != p->sched_class) {
  1666. if (prev_class->switched_from)
  1667. prev_class->switched_from(rq, p, running);
  1668. p->sched_class->switched_to(rq, p, running);
  1669. } else
  1670. p->sched_class->prio_changed(rq, p, oldprio, running);
  1671. }
  1672. #ifdef CONFIG_SMP
  1673. /*
  1674. * Is this task likely cache-hot:
  1675. */
  1676. static int
  1677. task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
  1678. {
  1679. s64 delta;
  1680. if (p->sched_class != &fair_sched_class)
  1681. return 0;
  1682. /*
  1683. * Buddy candidates are cache hot:
  1684. */
  1685. if (sched_feat(CACHE_HOT_BUDDY) && this_rq()->nr_running &&
  1686. (&p->se == cfs_rq_of(&p->se)->next ||
  1687. &p->se == cfs_rq_of(&p->se)->last))
  1688. return 1;
  1689. if (sysctl_sched_migration_cost == -1)
  1690. return 1;
  1691. if (sysctl_sched_migration_cost == 0)
  1692. return 0;
  1693. delta = now - p->se.exec_start;
  1694. return delta < (s64)sysctl_sched_migration_cost;
  1695. }
  1696. void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
  1697. {
  1698. #ifdef CONFIG_SCHED_DEBUG
  1699. /*
  1700. * We should never call set_task_cpu() on a blocked task,
  1701. * ttwu() will sort out the placement.
  1702. */
  1703. WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING &&
  1704. !(task_thread_info(p)->preempt_count & PREEMPT_ACTIVE));
  1705. #endif
  1706. trace_sched_migrate_task(p, new_cpu);
  1707. if (task_cpu(p) != new_cpu) {
  1708. p->se.nr_migrations++;
  1709. perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, 1, 1, NULL, 0);
  1710. }
  1711. __set_task_cpu(p, new_cpu);
  1712. }
  1713. struct migration_req {
  1714. struct list_head list;
  1715. struct task_struct *task;
  1716. int dest_cpu;
  1717. struct completion done;
  1718. };
  1719. /*
  1720. * The task's runqueue lock must be held.
  1721. * Returns true if you have to wait for migration thread.
  1722. */
  1723. static int
  1724. migrate_task(struct task_struct *p, int dest_cpu, struct migration_req *req)
  1725. {
  1726. struct rq *rq = task_rq(p);
  1727. /*
  1728. * If the task is not on a runqueue (and not running), then
  1729. * the next wake-up will properly place the task.
  1730. */
  1731. if (!p->se.on_rq && !task_running(rq, p))
  1732. return 0;
  1733. init_completion(&req->done);
  1734. req->task = p;
  1735. req->dest_cpu = dest_cpu;
  1736. list_add(&req->list, &rq->migration_queue);
  1737. return 1;
  1738. }
  1739. /*
  1740. * wait_task_context_switch - wait for a thread to complete at least one
  1741. * context switch.
  1742. *
  1743. * @p must not be current.
  1744. */
  1745. void wait_task_context_switch(struct task_struct *p)
  1746. {
  1747. unsigned long nvcsw, nivcsw, flags;
  1748. int running;
  1749. struct rq *rq;
  1750. nvcsw = p->nvcsw;
  1751. nivcsw = p->nivcsw;
  1752. for (;;) {
  1753. /*
  1754. * The runqueue is assigned before the actual context
  1755. * switch. We need to take the runqueue lock.
  1756. *
  1757. * We could check initially without the lock but it is
  1758. * very likely that we need to take the lock in every
  1759. * iteration.
  1760. */
  1761. rq = task_rq_lock(p, &flags);
  1762. running = task_running(rq, p);
  1763. task_rq_unlock(rq, &flags);
  1764. if (likely(!running))
  1765. break;
  1766. /*
  1767. * The switch count is incremented before the actual
  1768. * context switch. We thus wait for two switches to be
  1769. * sure at least one completed.
  1770. */
  1771. if ((p->nvcsw - nvcsw) > 1)
  1772. break;
  1773. if ((p->nivcsw - nivcsw) > 1)
  1774. break;
  1775. cpu_relax();
  1776. }
  1777. }
  1778. /*
  1779. * wait_task_inactive - wait for a thread to unschedule.
  1780. *
  1781. * If @match_state is nonzero, it's the @p->state value just checked and
  1782. * not expected to change. If it changes, i.e. @p might have woken up,
  1783. * then return zero. When we succeed in waiting for @p to be off its CPU,
  1784. * we return a positive number (its total switch count). If a second call
  1785. * a short while later returns the same number, the caller can be sure that
  1786. * @p has remained unscheduled the whole time.
  1787. *
  1788. * The caller must ensure that the task *will* unschedule sometime soon,
  1789. * else this function might spin for a *long* time. This function can't
  1790. * be called with interrupts off, or it may introduce deadlock with
  1791. * smp_call_function() if an IPI is sent by the same process we are
  1792. * waiting to become inactive.
  1793. */
  1794. unsigned long wait_task_inactive(struct task_struct *p, long match_state)
  1795. {
  1796. unsigned long flags;
  1797. int running, on_rq;
  1798. unsigned long ncsw;
  1799. struct rq *rq;
  1800. for (;;) {
  1801. /*
  1802. * We do the initial early heuristics without holding
  1803. * any task-queue locks at all. We'll only try to get
  1804. * the runqueue lock when things look like they will
  1805. * work out!
  1806. */
  1807. rq = task_rq(p);
  1808. /*
  1809. * If the task is actively running on another CPU
  1810. * still, just relax and busy-wait without holding
  1811. * any locks.
  1812. *
  1813. * NOTE! Since we don't hold any locks, it's not
  1814. * even sure that "rq" stays as the right runqueue!
  1815. * But we don't care, since "task_running()" will
  1816. * return false if the runqueue has changed and p
  1817. * is actually now running somewhere else!
  1818. */
  1819. while (task_running(rq, p)) {
  1820. if (match_state && unlikely(p->state != match_state))
  1821. return 0;
  1822. cpu_relax();
  1823. }
  1824. /*
  1825. * Ok, time to look more closely! We need the rq
  1826. * lock now, to be *sure*. If we're wrong, we'll
  1827. * just go back and repeat.
  1828. */
  1829. rq = task_rq_lock(p, &flags);
  1830. trace_sched_wait_task(rq, p);
  1831. running = task_running(rq, p);
  1832. on_rq = p->se.on_rq;
  1833. ncsw = 0;
  1834. if (!match_state || p->state == match_state)
  1835. ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
  1836. task_rq_unlock(rq, &flags);
  1837. /*
  1838. * If it changed from the expected state, bail out now.
  1839. */
  1840. if (unlikely(!ncsw))
  1841. break;
  1842. /*
  1843. * Was it really running after all now that we
  1844. * checked with the proper locks actually held?
  1845. *
  1846. * Oops. Go back and try again..
  1847. */
  1848. if (unlikely(running)) {
  1849. cpu_relax();
  1850. continue;
  1851. }
  1852. /*
  1853. * It's not enough that it's not actively running,
  1854. * it must be off the runqueue _entirely_, and not
  1855. * preempted!
  1856. *
  1857. * So if it was still runnable (but just not actively
  1858. * running right now), it's preempted, and we should
  1859. * yield - it could be a while.
  1860. */
  1861. if (unlikely(on_rq)) {
  1862. schedule_timeout_uninterruptible(1);
  1863. continue;
  1864. }
  1865. /*
  1866. * Ahh, all good. It wasn't running, and it wasn't
  1867. * runnable, which means that it will never become
  1868. * running in the future either. We're all done!
  1869. */
  1870. break;
  1871. }
  1872. return ncsw;
  1873. }
  1874. /***
  1875. * kick_process - kick a running thread to enter/exit the kernel
  1876. * @p: the to-be-kicked thread
  1877. *
  1878. * Cause a process which is running on another CPU to enter
  1879. * kernel-mode, without any delay. (to get signals handled.)
  1880. *
  1881. * NOTE: this function doesnt have to take the runqueue lock,
  1882. * because all it wants to ensure is that the remote task enters
  1883. * the kernel. If the IPI races and the task has been migrated
  1884. * to another CPU then no harm is done and the purpose has been
  1885. * achieved as well.
  1886. */
  1887. void kick_process(struct task_struct *p)
  1888. {
  1889. int cpu;
  1890. preempt_disable();
  1891. cpu = task_cpu(p);
  1892. if ((cpu != smp_processor_id()) && task_curr(p))
  1893. smp_send_reschedule(cpu);
  1894. preempt_enable();
  1895. }
  1896. EXPORT_SYMBOL_GPL(kick_process);
  1897. #endif /* CONFIG_SMP */
  1898. /**
  1899. * task_oncpu_function_call - call a function on the cpu on which a task runs
  1900. * @p: the task to evaluate
  1901. * @func: the function to be called
  1902. * @info: the function call argument
  1903. *
  1904. * Calls the function @func when the task is currently running. This might
  1905. * be on the current CPU, which just calls the function directly
  1906. */
  1907. void task_oncpu_function_call(struct task_struct *p,
  1908. void (*func) (void *info), void *info)
  1909. {
  1910. int cpu;
  1911. preempt_disable();
  1912. cpu = task_cpu(p);
  1913. if (task_curr(p))
  1914. smp_call_function_single(cpu, func, info, 1);
  1915. preempt_enable();
  1916. }
  1917. #ifdef CONFIG_SMP
  1918. static int select_fallback_rq(int cpu, struct task_struct *p)
  1919. {
  1920. int dest_cpu;
  1921. const struct cpumask *nodemask = cpumask_of_node(cpu_to_node(cpu));
  1922. /* Look for allowed, online CPU in same node. */
  1923. for_each_cpu_and(dest_cpu, nodemask, cpu_active_mask)
  1924. if (cpumask_test_cpu(dest_cpu, &p->cpus_allowed))
  1925. return dest_cpu;
  1926. /* Any allowed, online CPU? */
  1927. dest_cpu = cpumask_any_and(&p->cpus_allowed, cpu_active_mask);
  1928. if (dest_cpu < nr_cpu_ids)
  1929. return dest_cpu;
  1930. /* No more Mr. Nice Guy. */
  1931. if (dest_cpu >= nr_cpu_ids) {
  1932. rcu_read_lock();
  1933. cpuset_cpus_allowed_locked(p, &p->cpus_allowed);
  1934. rcu_read_unlock();
  1935. dest_cpu = cpumask_any_and(cpu_active_mask, &p->cpus_allowed);
  1936. /*
  1937. * Don't tell them about moving exiting tasks or
  1938. * kernel threads (both mm NULL), since they never
  1939. * leave kernel.
  1940. */
  1941. if (p->mm && printk_ratelimit()) {
  1942. printk(KERN_INFO "process %d (%s) no "
  1943. "longer affine to cpu%d\n",
  1944. task_pid_nr(p), p->comm, cpu);
  1945. }
  1946. }
  1947. return dest_cpu;
  1948. }
  1949. /*
  1950. * Gets called from 3 sites (exec, fork, wakeup), since it is called without
  1951. * holding rq->lock we need to ensure ->cpus_allowed is stable, this is done
  1952. * by:
  1953. *
  1954. * exec: is unstable, retry loop
  1955. * fork & wake-up: serialize ->cpus_allowed against TASK_WAKING
  1956. */
  1957. static inline
  1958. int select_task_rq(struct task_struct *p, int sd_flags, int wake_flags)
  1959. {
  1960. int cpu = p->sched_class->select_task_rq(p, sd_flags, wake_flags);
  1961. /*
  1962. * In order not to call set_task_cpu() on a blocking task we need
  1963. * to rely on ttwu() to place the task on a valid ->cpus_allowed
  1964. * cpu.
  1965. *
  1966. * Since this is common to all placement strategies, this lives here.
  1967. *
  1968. * [ this allows ->select_task() to simply return task_cpu(p) and
  1969. * not worry about this generic constraint ]
  1970. */
  1971. if (unlikely(!cpumask_test_cpu(cpu, &p->cpus_allowed) ||
  1972. !cpu_online(cpu)))
  1973. cpu = select_fallback_rq(task_cpu(p), p);
  1974. return cpu;
  1975. }
  1976. #endif
  1977. /***
  1978. * try_to_wake_up - wake up a thread
  1979. * @p: the to-be-woken-up thread
  1980. * @state: the mask of task states that can be woken
  1981. * @sync: do a synchronous wakeup?
  1982. *
  1983. * Put it on the run-queue if it's not already there. The "current"
  1984. * thread is always on the run-queue (except when the actual
  1985. * re-schedule is in progress), and as such you're allowed to do
  1986. * the simpler "current->state = TASK_RUNNING" to mark yourself
  1987. * runnable without the overhead of this.
  1988. *
  1989. * returns failure only if the task is already active.
  1990. */
  1991. static int try_to_wake_up(struct task_struct *p, unsigned int state,
  1992. int wake_flags)
  1993. {
  1994. int cpu, orig_cpu, this_cpu, success = 0;
  1995. unsigned long flags;
  1996. struct rq *rq;
  1997. if (!sched_feat(SYNC_WAKEUPS))
  1998. wake_flags &= ~WF_SYNC;
  1999. this_cpu = get_cpu();
  2000. smp_wmb();
  2001. rq = task_rq_lock(p, &flags);
  2002. if (!(p->state & state))
  2003. goto out;
  2004. if (p->se.on_rq)
  2005. goto out_running;
  2006. cpu = task_cpu(p);
  2007. orig_cpu = cpu;
  2008. #ifdef CONFIG_SMP
  2009. if (unlikely(task_running(rq, p)))
  2010. goto out_activate;
  2011. /*
  2012. * In order to handle concurrent wakeups and release the rq->lock
  2013. * we put the task in TASK_WAKING state.
  2014. *
  2015. * First fix up the nr_uninterruptible count:
  2016. */
  2017. if (task_contributes_to_load(p))
  2018. rq->nr_uninterruptible--;
  2019. p->state = TASK_WAKING;
  2020. if (p->sched_class->task_waking)
  2021. p->sched_class->task_waking(rq, p);
  2022. __task_rq_unlock(rq);
  2023. cpu = select_task_rq(p, SD_BALANCE_WAKE, wake_flags);
  2024. if (cpu != orig_cpu) {
  2025. /*
  2026. * Since we migrate the task without holding any rq->lock,
  2027. * we need to be careful with task_rq_lock(), since that
  2028. * might end up locking an invalid rq.
  2029. */
  2030. set_task_cpu(p, cpu);
  2031. }
  2032. rq = cpu_rq(cpu);
  2033. raw_spin_lock(&rq->lock);
  2034. /*
  2035. * We migrated the task without holding either rq->lock, however
  2036. * since the task is not on the task list itself, nobody else
  2037. * will try and migrate the task, hence the rq should match the
  2038. * cpu we just moved it to.
  2039. */
  2040. WARN_ON(task_cpu(p) != cpu);
  2041. WARN_ON(p->state != TASK_WAKING);
  2042. #ifdef CONFIG_SCHEDSTATS
  2043. schedstat_inc(rq, ttwu_count);
  2044. if (cpu == this_cpu)
  2045. schedstat_inc(rq, ttwu_local);
  2046. else {
  2047. struct sched_domain *sd;
  2048. for_each_domain(this_cpu, sd) {
  2049. if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
  2050. schedstat_inc(sd, ttwu_wake_remote);
  2051. break;
  2052. }
  2053. }
  2054. }
  2055. #endif /* CONFIG_SCHEDSTATS */
  2056. out_activate:
  2057. #endif /* CONFIG_SMP */
  2058. schedstat_inc(p, se.statistics.nr_wakeups);
  2059. if (wake_flags & WF_SYNC)
  2060. schedstat_inc(p, se.statistics.nr_wakeups_sync);
  2061. if (orig_cpu != cpu)
  2062. schedstat_inc(p, se.statistics.nr_wakeups_migrate);
  2063. if (cpu == this_cpu)
  2064. schedstat_inc(p, se.statistics.nr_wakeups_local);
  2065. else
  2066. schedstat_inc(p, se.statistics.nr_wakeups_remote);
  2067. activate_task(rq, p, 1);
  2068. success = 1;
  2069. out_running:
  2070. trace_sched_wakeup(rq, p, success);
  2071. check_preempt_curr(rq, p, wake_flags);
  2072. p->state = TASK_RUNNING;
  2073. #ifdef CONFIG_SMP
  2074. if (p->sched_class->task_woken)
  2075. p->sched_class->task_woken(rq, p);
  2076. if (unlikely(rq->idle_stamp)) {
  2077. u64 delta = rq->clock - rq->idle_stamp;
  2078. u64 max = 2*sysctl_sched_migration_cost;
  2079. if (delta > max)
  2080. rq->avg_idle = max;
  2081. else
  2082. update_avg(&rq->avg_idle, delta);
  2083. rq->idle_stamp = 0;
  2084. }
  2085. #endif
  2086. out:
  2087. task_rq_unlock(rq, &flags);
  2088. put_cpu();
  2089. return success;
  2090. }
  2091. /**
  2092. * wake_up_process - Wake up a specific process
  2093. * @p: The process to be woken up.
  2094. *
  2095. * Attempt to wake up the nominated process and move it to the set of runnable
  2096. * processes. Returns 1 if the process was woken up, 0 if it was already
  2097. * running.
  2098. *
  2099. * It may be assumed that this function implies a write memory barrier before
  2100. * changing the task state if and only if any tasks are woken up.
  2101. */
  2102. int wake_up_process(struct task_struct *p)
  2103. {
  2104. return try_to_wake_up(p, TASK_ALL, 0);
  2105. }
  2106. EXPORT_SYMBOL(wake_up_process);
  2107. int wake_up_state(struct task_struct *p, unsigned int state)
  2108. {
  2109. return try_to_wake_up(p, state, 0);
  2110. }
  2111. /*
  2112. * Perform scheduler related setup for a newly forked process p.
  2113. * p is forked by current.
  2114. *
  2115. * __sched_fork() is basic setup used by init_idle() too:
  2116. */
  2117. static void __sched_fork(struct task_struct *p)
  2118. {
  2119. p->se.exec_start = 0;
  2120. p->se.sum_exec_runtime = 0;
  2121. p->se.prev_sum_exec_runtime = 0;
  2122. p->se.nr_migrations = 0;
  2123. #ifdef CONFIG_SCHEDSTATS
  2124. memset(&p->se.statistics, 0, sizeof(p->se.statistics));
  2125. #endif
  2126. INIT_LIST_HEAD(&p->rt.run_list);
  2127. p->se.on_rq = 0;
  2128. INIT_LIST_HEAD(&p->se.group_node);
  2129. #ifdef CONFIG_PREEMPT_NOTIFIERS
  2130. INIT_HLIST_HEAD(&p->preempt_notifiers);
  2131. #endif
  2132. }
  2133. /*
  2134. * fork()/clone()-time setup:
  2135. */
  2136. void sched_fork(struct task_struct *p, int clone_flags)
  2137. {
  2138. int cpu = get_cpu();
  2139. __sched_fork(p);
  2140. /*
  2141. * We mark the process as waking here. This guarantees that
  2142. * nobody will actually run it, and a signal or other external
  2143. * event cannot wake it up and insert it on the runqueue either.
  2144. */
  2145. p->state = TASK_WAKING;
  2146. /*
  2147. * Revert to default priority/policy on fork if requested.
  2148. */
  2149. if (unlikely(p->sched_reset_on_fork)) {
  2150. if (p->policy == SCHED_FIFO || p->policy == SCHED_RR) {
  2151. p->policy = SCHED_NORMAL;
  2152. p->normal_prio = p->static_prio;
  2153. }
  2154. if (PRIO_TO_NICE(p->static_prio) < 0) {
  2155. p->static_prio = NICE_TO_PRIO(0);
  2156. p->normal_prio = p->static_prio;
  2157. set_load_weight(p);
  2158. }
  2159. /*
  2160. * We don't need the reset flag anymore after the fork. It has
  2161. * fulfilled its duty:
  2162. */
  2163. p->sched_reset_on_fork = 0;
  2164. }
  2165. /*
  2166. * Make sure we do not leak PI boosting priority to the child.
  2167. */
  2168. p->prio = current->normal_prio;
  2169. if (!rt_prio(p->prio))
  2170. p->sched_class = &fair_sched_class;
  2171. if (p->sched_class->task_fork)
  2172. p->sched_class->task_fork(p);
  2173. set_task_cpu(p, cpu);
  2174. #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
  2175. if (likely(sched_info_on()))
  2176. memset(&p->sched_info, 0, sizeof(p->sched_info));
  2177. #endif
  2178. #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
  2179. p->oncpu = 0;
  2180. #endif
  2181. #ifdef CONFIG_PREEMPT
  2182. /* Want to start with kernel preemption disabled. */
  2183. task_thread_info(p)->preempt_count = 1;
  2184. #endif
  2185. plist_node_init(&p->pushable_tasks, MAX_PRIO);
  2186. put_cpu();
  2187. }
  2188. /*
  2189. * wake_up_new_task - wake up a newly created task for the first time.
  2190. *
  2191. * This function will do some initial scheduler statistics housekeeping
  2192. * that must be done for every newly created context, then puts the task
  2193. * on the runqueue and wakes it.
  2194. */
  2195. void wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
  2196. {
  2197. unsigned long flags;
  2198. struct rq *rq;
  2199. int cpu = get_cpu();
  2200. #ifdef CONFIG_SMP
  2201. /*
  2202. * Fork balancing, do it here and not earlier because:
  2203. * - cpus_allowed can change in the fork path
  2204. * - any previously selected cpu might disappear through hotplug
  2205. *
  2206. * We still have TASK_WAKING but PF_STARTING is gone now, meaning
  2207. * ->cpus_allowed is stable, we have preemption disabled, meaning
  2208. * cpu_online_mask is stable.
  2209. */
  2210. cpu = select_task_rq(p, SD_BALANCE_FORK, 0);
  2211. set_task_cpu(p, cpu);
  2212. #endif
  2213. /*
  2214. * Since the task is not on the rq and we still have TASK_WAKING set
  2215. * nobody else will migrate this task.
  2216. */
  2217. rq = cpu_rq(cpu);
  2218. raw_spin_lock_irqsave(&rq->lock, flags);
  2219. BUG_ON(p->state != TASK_WAKING);
  2220. p->state = TASK_RUNNING;
  2221. activate_task(rq, p, 0);
  2222. trace_sched_wakeup_new(rq, p, 1);
  2223. check_preempt_curr(rq, p, WF_FORK);
  2224. #ifdef CONFIG_SMP
  2225. if (p->sched_class->task_woken)
  2226. p->sched_class->task_woken(rq, p);
  2227. #endif
  2228. task_rq_unlock(rq, &flags);
  2229. put_cpu();
  2230. }
  2231. #ifdef CONFIG_PREEMPT_NOTIFIERS
  2232. /**
  2233. * preempt_notifier_register - tell me when current is being preempted & rescheduled
  2234. * @notifier: notifier struct to register
  2235. */
  2236. void preempt_notifier_register(struct preempt_notifier *notifier)
  2237. {
  2238. hlist_add_head(&notifier->link, &current->preempt_notifiers);
  2239. }
  2240. EXPORT_SYMBOL_GPL(preempt_notifier_register);
  2241. /**
  2242. * preempt_notifier_unregister - no longer interested in preemption notifications
  2243. * @notifier: notifier struct to unregister
  2244. *
  2245. * This is safe to call from within a preemption notifier.
  2246. */
  2247. void preempt_notifier_unregister(struct preempt_notifier *notifier)
  2248. {
  2249. hlist_del(&notifier->link);
  2250. }
  2251. EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
  2252. static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
  2253. {
  2254. struct preempt_notifier *notifier;
  2255. struct hlist_node *node;
  2256. hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
  2257. notifier->ops->sched_in(notifier, raw_smp_processor_id());
  2258. }
  2259. static void
  2260. fire_sched_out_preempt_notifiers(struct task_struct *curr,
  2261. struct task_struct *next)
  2262. {
  2263. struct preempt_notifier *notifier;
  2264. struct hlist_node *node;
  2265. hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
  2266. notifier->ops->sched_out(notifier, next);
  2267. }
  2268. #else /* !CONFIG_PREEMPT_NOTIFIERS */
  2269. static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
  2270. {
  2271. }
  2272. static void
  2273. fire_sched_out_preempt_notifiers(struct task_struct *curr,
  2274. struct task_struct *next)
  2275. {
  2276. }
  2277. #endif /* CONFIG_PREEMPT_NOTIFIERS */
  2278. /**
  2279. * prepare_task_switch - prepare to switch tasks
  2280. * @rq: the runqueue preparing to switch
  2281. * @prev: the current task that is being switched out
  2282. * @next: the task we are going to switch to.
  2283. *
  2284. * This is called with the rq lock held and interrupts off. It must
  2285. * be paired with a subsequent finish_task_switch after the context
  2286. * switch.
  2287. *
  2288. * prepare_task_switch sets up locking and calls architecture specific
  2289. * hooks.
  2290. */
  2291. static inline void
  2292. prepare_task_switch(struct rq *rq, struct task_struct *prev,
  2293. struct task_struct *next)
  2294. {
  2295. fire_sched_out_preempt_notifiers(prev, next);
  2296. prepare_lock_switch(rq, next);
  2297. prepare_arch_switch(next);
  2298. }
  2299. /**
  2300. * finish_task_switch - clean up after a task-switch
  2301. * @rq: runqueue associated with task-switch
  2302. * @prev: the thread we just switched away from.
  2303. *
  2304. * finish_task_switch must be called after the context switch, paired
  2305. * with a prepare_task_switch call before the context switch.
  2306. * finish_task_switch will reconcile locking set up by prepare_task_switch,
  2307. * and do any other architecture-specific cleanup actions.
  2308. *
  2309. * Note that we may have delayed dropping an mm in context_switch(). If
  2310. * so, we finish that here outside of the runqueue lock. (Doing it
  2311. * with the lock held can cause deadlocks; see schedule() for
  2312. * details.)
  2313. */
  2314. static void finish_task_switch(struct rq *rq, struct task_struct *prev)
  2315. __releases(rq->lock)
  2316. {
  2317. struct mm_struct *mm = rq->prev_mm;
  2318. long prev_state;
  2319. rq->prev_mm = NULL;
  2320. /*
  2321. * A task struct has one reference for the use as "current".
  2322. * If a task dies, then it sets TASK_DEAD in tsk->state and calls
  2323. * schedule one last time. The schedule call will never return, and
  2324. * the scheduled task must drop that reference.
  2325. * The test for TASK_DEAD must occur while the runqueue locks are
  2326. * still held, otherwise prev could be scheduled on another cpu, die
  2327. * there before we look at prev->state, and then the reference would
  2328. * be dropped twice.
  2329. * Manfred Spraul <manfred@colorfullife.com>
  2330. */
  2331. prev_state = prev->state;
  2332. finish_arch_switch(prev);
  2333. #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
  2334. local_irq_disable();
  2335. #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
  2336. perf_event_task_sched_in(current);
  2337. #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
  2338. local_irq_enable();
  2339. #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
  2340. finish_lock_switch(rq, prev);
  2341. fire_sched_in_preempt_notifiers(current);
  2342. if (mm)
  2343. mmdrop(mm);
  2344. if (unlikely(prev_state == TASK_DEAD)) {
  2345. /*
  2346. * Remove function-return probe instances associated with this
  2347. * task and put them back on the free list.
  2348. */
  2349. kprobe_flush_task(prev);
  2350. put_task_struct(prev);
  2351. }
  2352. }
  2353. #ifdef CONFIG_SMP
  2354. /* assumes rq->lock is held */
  2355. static inline void pre_schedule(struct rq *rq, struct task_struct *prev)
  2356. {
  2357. if (prev->sched_class->pre_schedule)
  2358. prev->sched_class->pre_schedule(rq, prev);
  2359. }
  2360. /* rq->lock is NOT held, but preemption is disabled */
  2361. static inline void post_schedule(struct rq *rq)
  2362. {
  2363. if (rq->post_schedule) {
  2364. unsigned long flags;
  2365. raw_spin_lock_irqsave(&rq->lock, flags);
  2366. if (rq->curr->sched_class->post_schedule)
  2367. rq->curr->sched_class->post_schedule(rq);
  2368. raw_spin_unlock_irqrestore(&rq->lock, flags);
  2369. rq->post_schedule = 0;
  2370. }
  2371. }
  2372. #else
  2373. static inline void pre_schedule(struct rq *rq, struct task_struct *p)
  2374. {
  2375. }
  2376. static inline void post_schedule(struct rq *rq)
  2377. {
  2378. }
  2379. #endif
  2380. /**
  2381. * schedule_tail - first thing a freshly forked thread must call.
  2382. * @prev: the thread we just switched away from.
  2383. */
  2384. asmlinkage void schedule_tail(struct task_struct *prev)
  2385. __releases(rq->lock)
  2386. {
  2387. struct rq *rq = this_rq();
  2388. finish_task_switch(rq, prev);
  2389. /*
  2390. * FIXME: do we need to worry about rq being invalidated by the
  2391. * task_switch?
  2392. */
  2393. post_schedule(rq);
  2394. #ifdef __ARCH_WANT_UNLOCKED_CTXSW
  2395. /* In this case, finish_task_switch does not reenable preemption */
  2396. preempt_enable();
  2397. #endif
  2398. if (current->set_child_tid)
  2399. put_user(task_pid_vnr(current), current->set_child_tid);
  2400. }
  2401. /*
  2402. * context_switch - switch to the new MM and the new
  2403. * thread's register state.
  2404. */
  2405. static inline void
  2406. context_switch(struct rq *rq, struct task_struct *prev,
  2407. struct task_struct *next)
  2408. {
  2409. struct mm_struct *mm, *oldmm;
  2410. prepare_task_switch(rq, prev, next);
  2411. trace_sched_switch(rq, prev, next);
  2412. mm = next->mm;
  2413. oldmm = prev->active_mm;
  2414. /*
  2415. * For paravirt, this is coupled with an exit in switch_to to
  2416. * combine the page table reload and the switch backend into
  2417. * one hypercall.
  2418. */
  2419. arch_start_context_switch(prev);
  2420. if (likely(!mm)) {
  2421. next->active_mm = oldmm;
  2422. atomic_inc(&oldmm->mm_count);
  2423. enter_lazy_tlb(oldmm, next);
  2424. } else
  2425. switch_mm(oldmm, mm, next);
  2426. if (likely(!prev->mm)) {
  2427. prev->active_mm = NULL;
  2428. rq->prev_mm = oldmm;
  2429. }
  2430. /*
  2431. * Since the runqueue lock will be released by the next
  2432. * task (which is an invalid locking op but in the case
  2433. * of the scheduler it's an obvious special-case), so we
  2434. * do an early lockdep release here:
  2435. */
  2436. #ifndef __ARCH_WANT_UNLOCKED_CTXSW
  2437. spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
  2438. #endif
  2439. /* Here we just switch the register state and the stack. */
  2440. switch_to(prev, next, prev);
  2441. barrier();
  2442. /*
  2443. * this_rq must be evaluated again because prev may have moved
  2444. * CPUs since it called schedule(), thus the 'rq' on its stack
  2445. * frame will be invalid.
  2446. */
  2447. finish_task_switch(this_rq(), prev);
  2448. }
  2449. /*
  2450. * nr_running, nr_uninterruptible and nr_context_switches:
  2451. *
  2452. * externally visible scheduler statistics: current number of runnable
  2453. * threads, current number of uninterruptible-sleeping threads, total
  2454. * number of context switches performed since bootup.
  2455. */
  2456. unsigned long nr_running(void)
  2457. {
  2458. unsigned long i, sum = 0;
  2459. for_each_online_cpu(i)
  2460. sum += cpu_rq(i)->nr_running;
  2461. return sum;
  2462. }
  2463. unsigned long nr_uninterruptible(void)
  2464. {
  2465. unsigned long i, sum = 0;
  2466. for_each_possible_cpu(i)
  2467. sum += cpu_rq(i)->nr_uninterruptible;
  2468. /*
  2469. * Since we read the counters lockless, it might be slightly
  2470. * inaccurate. Do not allow it to go below zero though:
  2471. */
  2472. if (unlikely((long)sum < 0))
  2473. sum = 0;
  2474. return sum;
  2475. }
  2476. unsigned long long nr_context_switches(void)
  2477. {
  2478. int i;
  2479. unsigned long long sum = 0;
  2480. for_each_possible_cpu(i)
  2481. sum += cpu_rq(i)->nr_switches;
  2482. return sum;
  2483. }
  2484. unsigned long nr_iowait(void)
  2485. {
  2486. unsigned long i, sum = 0;
  2487. for_each_possible_cpu(i)
  2488. sum += atomic_read(&cpu_rq(i)->nr_iowait);
  2489. return sum;
  2490. }
  2491. unsigned long nr_iowait_cpu(void)
  2492. {
  2493. struct rq *this = this_rq();
  2494. return atomic_read(&this->nr_iowait);
  2495. }
  2496. unsigned long this_cpu_load(void)
  2497. {
  2498. struct rq *this = this_rq();
  2499. return this->cpu_load[0];
  2500. }
  2501. /* Variables and functions for calc_load */
  2502. static atomic_long_t calc_load_tasks;
  2503. static unsigned long calc_load_update;
  2504. unsigned long avenrun[3];
  2505. EXPORT_SYMBOL(avenrun);
  2506. /**
  2507. * get_avenrun - get the load average array
  2508. * @loads: pointer to dest load array
  2509. * @offset: offset to add
  2510. * @shift: shift count to shift the result left
  2511. *
  2512. * These values are estimates at best, so no need for locking.
  2513. */
  2514. void get_avenrun(unsigned long *loads, unsigned long offset, int shift)
  2515. {
  2516. loads[0] = (avenrun[0] + offset) << shift;
  2517. loads[1] = (avenrun[1] + offset) << shift;
  2518. loads[2] = (avenrun[2] + offset) << shift;
  2519. }
  2520. static unsigned long
  2521. calc_load(unsigned long load, unsigned long exp, unsigned long active)
  2522. {
  2523. load *= exp;
  2524. load += active * (FIXED_1 - exp);
  2525. return load >> FSHIFT;
  2526. }
  2527. /*
  2528. * calc_load - update the avenrun load estimates 10 ticks after the
  2529. * CPUs have updated calc_load_tasks.
  2530. */
  2531. void calc_global_load(void)
  2532. {
  2533. unsigned long upd = calc_load_update + 10;
  2534. long active;
  2535. if (time_before(jiffies, upd))
  2536. return;
  2537. active = atomic_long_read(&calc_load_tasks);
  2538. active = active > 0 ? active * FIXED_1 : 0;
  2539. avenrun[0] = calc_load(avenrun[0], EXP_1, active);
  2540. avenrun[1] = calc_load(avenrun[1], EXP_5, active);
  2541. avenrun[2] = calc_load(avenrun[2], EXP_15, active);
  2542. calc_load_update += LOAD_FREQ;
  2543. }
  2544. /*
  2545. * Either called from update_cpu_load() or from a cpu going idle
  2546. */
  2547. static void calc_load_account_active(struct rq *this_rq)
  2548. {
  2549. long nr_active, delta;
  2550. nr_active = this_rq->nr_running;
  2551. nr_active += (long) this_rq->nr_uninterruptible;
  2552. if (nr_active != this_rq->calc_load_active) {
  2553. delta = nr_active - this_rq->calc_load_active;
  2554. this_rq->calc_load_active = nr_active;
  2555. atomic_long_add(delta, &calc_load_tasks);
  2556. }
  2557. }
  2558. /*
  2559. * Update rq->cpu_load[] statistics. This function is usually called every
  2560. * scheduler tick (TICK_NSEC).
  2561. */
  2562. static void update_cpu_load(struct rq *this_rq)
  2563. {
  2564. unsigned long this_load = this_rq->load.weight;
  2565. int i, scale;
  2566. this_rq->nr_load_updates++;
  2567. /* Update our load: */
  2568. for (i = 0, scale = 1; i < CPU_LOAD_IDX_MAX; i++, scale += scale) {
  2569. unsigned long old_load, new_load;
  2570. /* scale is effectively 1 << i now, and >> i divides by scale */
  2571. old_load = this_rq->cpu_load[i];
  2572. new_load = this_load;
  2573. /*
  2574. * Round up the averaging division if load is increasing. This
  2575. * prevents us from getting stuck on 9 if the load is 10, for
  2576. * example.
  2577. */
  2578. if (new_load > old_load)
  2579. new_load += scale-1;
  2580. this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) >> i;
  2581. }
  2582. if (time_after_eq(jiffies, this_rq->calc_load_update)) {
  2583. this_rq->calc_load_update += LOAD_FREQ;
  2584. calc_load_account_active(this_rq);
  2585. }
  2586. }
  2587. #ifdef CONFIG_SMP
  2588. /*
  2589. * sched_exec - execve() is a valuable balancing opportunity, because at
  2590. * this point the task has the smallest effective memory and cache footprint.
  2591. */
  2592. void sched_exec(void)
  2593. {
  2594. struct task_struct *p = current;
  2595. struct migration_req req;
  2596. int dest_cpu, this_cpu;
  2597. unsigned long flags;
  2598. struct rq *rq;
  2599. again:
  2600. this_cpu = get_cpu();
  2601. dest_cpu = select_task_rq(p, SD_BALANCE_EXEC, 0);
  2602. if (dest_cpu == this_cpu) {
  2603. put_cpu();
  2604. return;
  2605. }
  2606. rq = task_rq_lock(p, &flags);
  2607. put_cpu();
  2608. /*
  2609. * select_task_rq() can race against ->cpus_allowed
  2610. */
  2611. if (!cpumask_test_cpu(dest_cpu, &p->cpus_allowed)
  2612. || unlikely(!cpu_active(dest_cpu))) {
  2613. task_rq_unlock(rq, &flags);
  2614. goto again;
  2615. }
  2616. /* force the process onto the specified CPU */
  2617. if (migrate_task(p, dest_cpu, &req)) {
  2618. /* Need to wait for migration thread (might exit: take ref). */
  2619. struct task_struct *mt = rq->migration_thread;
  2620. get_task_struct(mt);
  2621. task_rq_unlock(rq, &flags);
  2622. wake_up_process(mt);
  2623. put_task_struct(mt);
  2624. wait_for_completion(&req.done);
  2625. return;
  2626. }
  2627. task_rq_unlock(rq, &flags);
  2628. }
  2629. #endif
  2630. DEFINE_PER_CPU(struct kernel_stat, kstat);
  2631. EXPORT_PER_CPU_SYMBOL(kstat);
  2632. /*
  2633. * Return any ns on the sched_clock that have not yet been accounted in
  2634. * @p in case that task is currently running.
  2635. *
  2636. * Called with task_rq_lock() held on @rq.
  2637. */
  2638. static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq)
  2639. {
  2640. u64 ns = 0;
  2641. if (task_current(rq, p)) {
  2642. update_rq_clock(rq);
  2643. ns = rq->clock - p->se.exec_start;
  2644. if ((s64)ns < 0)
  2645. ns = 0;
  2646. }
  2647. return ns;
  2648. }
  2649. unsigned long long task_delta_exec(struct task_struct *p)
  2650. {
  2651. unsigned long flags;
  2652. struct rq *rq;
  2653. u64 ns = 0;
  2654. rq = task_rq_lock(p, &flags);
  2655. ns = do_task_delta_exec(p, rq);
  2656. task_rq_unlock(rq, &flags);
  2657. return ns;
  2658. }
  2659. /*
  2660. * Return accounted runtime for the task.
  2661. * In case the task is currently running, return the runtime plus current's
  2662. * pending runtime that have not been accounted yet.
  2663. */
  2664. unsigned long long task_sched_runtime(struct task_struct *p)
  2665. {
  2666. unsigned long flags;
  2667. struct rq *rq;
  2668. u64 ns = 0;
  2669. rq = task_rq_lock(p, &flags);
  2670. ns = p->se.sum_exec_runtime + do_task_delta_exec(p, rq);
  2671. task_rq_unlock(rq, &flags);
  2672. return ns;
  2673. }
  2674. /*
  2675. * Return sum_exec_runtime for the thread group.
  2676. * In case the task is currently running, return the sum plus current's
  2677. * pending runtime that have not been accounted yet.
  2678. *
  2679. * Note that the thread group might have other running tasks as well,
  2680. * so the return value not includes other pending runtime that other
  2681. * running tasks might have.
  2682. */
  2683. unsigned long long thread_group_sched_runtime(struct task_struct *p)
  2684. {
  2685. struct task_cputime totals;
  2686. unsigned long flags;
  2687. struct rq *rq;
  2688. u64 ns;
  2689. rq = task_rq_lock(p, &flags);
  2690. thread_group_cputime(p, &totals);
  2691. ns = totals.sum_exec_runtime + do_task_delta_exec(p, rq);
  2692. task_rq_unlock(rq, &flags);
  2693. return ns;
  2694. }
  2695. /*
  2696. * Account user cpu time to a process.
  2697. * @p: the process that the cpu time gets accounted to
  2698. * @cputime: the cpu time spent in user space since the last update
  2699. * @cputime_scaled: cputime scaled by cpu frequency
  2700. */
  2701. void account_user_time(struct task_struct *p, cputime_t cputime,
  2702. cputime_t cputime_scaled)
  2703. {
  2704. struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
  2705. cputime64_t tmp;
  2706. /* Add user time to process. */
  2707. p->utime = cputime_add(p->utime, cputime);
  2708. p->utimescaled = cputime_add(p->utimescaled, cputime_scaled);
  2709. account_group_user_time(p, cputime);
  2710. /* Add user time to cpustat. */
  2711. tmp = cputime_to_cputime64(cputime);
  2712. if (TASK_NICE(p) > 0)
  2713. cpustat->nice = cputime64_add(cpustat->nice, tmp);
  2714. else
  2715. cpustat->user = cputime64_add(cpustat->user, tmp);
  2716. cpuacct_update_stats(p, CPUACCT_STAT_USER, cputime);
  2717. /* Account for user time used */
  2718. acct_update_integrals(p);
  2719. }
  2720. /*
  2721. * Account guest cpu time to a process.
  2722. * @p: the process that the cpu time gets accounted to
  2723. * @cputime: the cpu time spent in virtual machine since the last update
  2724. * @cputime_scaled: cputime scaled by cpu frequency
  2725. */
  2726. static void account_guest_time(struct task_struct *p, cputime_t cputime,
  2727. cputime_t cputime_scaled)
  2728. {
  2729. cputime64_t tmp;
  2730. struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
  2731. tmp = cputime_to_cputime64(cputime);
  2732. /* Add guest time to process. */
  2733. p->utime = cputime_add(p->utime, cputime);
  2734. p->utimescaled = cputime_add(p->utimescaled, cputime_scaled);
  2735. account_group_user_time(p, cputime);
  2736. p->gtime = cputime_add(p->gtime, cputime);
  2737. /* Add guest time to cpustat. */
  2738. if (TASK_NICE(p) > 0) {
  2739. cpustat->nice = cputime64_add(cpustat->nice, tmp);
  2740. cpustat->guest_nice = cputime64_add(cpustat->guest_nice, tmp);
  2741. } else {
  2742. cpustat->user = cputime64_add(cpustat->user, tmp);
  2743. cpustat->guest = cputime64_add(cpustat->guest, tmp);
  2744. }
  2745. }
  2746. /*
  2747. * Account system cpu time to a process.
  2748. * @p: the process that the cpu time gets accounted to
  2749. * @hardirq_offset: the offset to subtract from hardirq_count()
  2750. * @cputime: the cpu time spent in kernel space since the last update
  2751. * @cputime_scaled: cputime scaled by cpu frequency
  2752. */
  2753. void account_system_time(struct task_struct *p, int hardirq_offset,
  2754. cputime_t cputime, cputime_t cputime_scaled)
  2755. {
  2756. struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
  2757. cputime64_t tmp;
  2758. if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
  2759. account_guest_time(p, cputime, cputime_scaled);
  2760. return;
  2761. }
  2762. /* Add system time to process. */
  2763. p->stime = cputime_add(p->stime, cputime);
  2764. p->stimescaled = cputime_add(p->stimescaled, cputime_scaled);
  2765. account_group_system_time(p, cputime);
  2766. /* Add system time to cpustat. */
  2767. tmp = cputime_to_cputime64(cputime);
  2768. if (hardirq_count() - hardirq_offset)
  2769. cpustat->irq = cputime64_add(cpustat->irq, tmp);
  2770. else if (softirq_count())
  2771. cpustat->softirq = cputime64_add(cpustat->softirq, tmp);
  2772. else
  2773. cpustat->system = cputime64_add(cpustat->system, tmp);
  2774. cpuacct_update_stats(p, CPUACCT_STAT_SYSTEM, cputime);
  2775. /* Account for system time used */
  2776. acct_update_integrals(p);
  2777. }
  2778. /*
  2779. * Account for involuntary wait time.
  2780. * @steal: the cpu time spent in involuntary wait
  2781. */
  2782. void account_steal_time(cputime_t cputime)
  2783. {
  2784. struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
  2785. cputime64_t cputime64 = cputime_to_cputime64(cputime);
  2786. cpustat->steal = cputime64_add(cpustat->steal, cputime64);
  2787. }
  2788. /*
  2789. * Account for idle time.
  2790. * @cputime: the cpu time spent in idle wait
  2791. */
  2792. void account_idle_time(cputime_t cputime)
  2793. {
  2794. struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
  2795. cputime64_t cputime64 = cputime_to_cputime64(cputime);
  2796. struct rq *rq = this_rq();
  2797. if (atomic_read(&rq->nr_iowait) > 0)
  2798. cpustat->iowait = cputime64_add(cpustat->iowait, cputime64);
  2799. else
  2800. cpustat->idle = cputime64_add(cpustat->idle, cputime64);
  2801. }
  2802. #ifndef CONFIG_VIRT_CPU_ACCOUNTING
  2803. /*
  2804. * Account a single tick of cpu time.
  2805. * @p: the process that the cpu time gets accounted to
  2806. * @user_tick: indicates if the tick is a user or a system tick
  2807. */
  2808. void account_process_tick(struct task_struct *p, int user_tick)
  2809. {
  2810. cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);
  2811. struct rq *rq = this_rq();
  2812. if (user_tick)
  2813. account_user_time(p, cputime_one_jiffy, one_jiffy_scaled);
  2814. else if ((p != rq->idle) || (irq_count() != HARDIRQ_OFFSET))
  2815. account_system_time(p, HARDIRQ_OFFSET, cputime_one_jiffy,
  2816. one_jiffy_scaled);
  2817. else
  2818. account_idle_time(cputime_one_jiffy);
  2819. }
  2820. /*
  2821. * Account multiple ticks of steal time.
  2822. * @p: the process from which the cpu time has been stolen
  2823. * @ticks: number of stolen ticks
  2824. */
  2825. void account_steal_ticks(unsigned long ticks)
  2826. {
  2827. account_steal_time(jiffies_to_cputime(ticks));
  2828. }
  2829. /*
  2830. * Account multiple ticks of idle time.
  2831. * @ticks: number of stolen ticks
  2832. */
  2833. void account_idle_ticks(unsigned long ticks)
  2834. {
  2835. account_idle_time(jiffies_to_cputime(ticks));
  2836. }
  2837. #endif
  2838. /*
  2839. * Use precise platform statistics if available:
  2840. */
  2841. #ifdef CONFIG_VIRT_CPU_ACCOUNTING
  2842. void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
  2843. {
  2844. *ut = p->utime;
  2845. *st = p->stime;
  2846. }
  2847. void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
  2848. {
  2849. struct task_cputime cputime;
  2850. thread_group_cputime(p, &cputime);
  2851. *ut = cputime.utime;
  2852. *st = cputime.stime;
  2853. }
  2854. #else
  2855. #ifndef nsecs_to_cputime
  2856. # define nsecs_to_cputime(__nsecs) nsecs_to_jiffies(__nsecs)
  2857. #endif
  2858. void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
  2859. {
  2860. cputime_t rtime, utime = p->utime, total = cputime_add(utime, p->stime);
  2861. /*
  2862. * Use CFS's precise accounting:
  2863. */
  2864. rtime = nsecs_to_cputime(p->se.sum_exec_runtime);
  2865. if (total) {
  2866. u64 temp;
  2867. temp = (u64)(rtime * utime);
  2868. do_div(temp, total);
  2869. utime = (cputime_t)temp;
  2870. } else
  2871. utime = rtime;
  2872. /*
  2873. * Compare with previous values, to keep monotonicity:
  2874. */
  2875. p->prev_utime = max(p->prev_utime, utime);
  2876. p->prev_stime = max(p->prev_stime, cputime_sub(rtime, p->prev_utime));
  2877. *ut = p->prev_utime;
  2878. *st = p->prev_stime;
  2879. }
  2880. /*
  2881. * Must be called with siglock held.
  2882. */
  2883. void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
  2884. {
  2885. struct signal_struct *sig = p->signal;
  2886. struct task_cputime cputime;
  2887. cputime_t rtime, utime, total;
  2888. thread_group_cputime(p, &cputime);
  2889. total = cputime_add(cputime.utime, cputime.stime);
  2890. rtime = nsecs_to_cputime(cputime.sum_exec_runtime);
  2891. if (total) {
  2892. u64 temp;
  2893. temp = (u64)(rtime * cputime.utime);
  2894. do_div(temp, total);
  2895. utime = (cputime_t)temp;
  2896. } else
  2897. utime = rtime;
  2898. sig->prev_utime = max(sig->prev_utime, utime);
  2899. sig->prev_stime = max(sig->prev_stime,
  2900. cputime_sub(rtime, sig->prev_utime));
  2901. *ut = sig->prev_utime;
  2902. *st = sig->prev_stime;
  2903. }
  2904. #endif
  2905. /*
  2906. * This function gets called by the timer code, with HZ frequency.
  2907. * We call it with interrupts disabled.
  2908. *
  2909. * It also gets called by the fork code, when changing the parent's
  2910. * timeslices.
  2911. */
  2912. void scheduler_tick(void)
  2913. {
  2914. int cpu = smp_processor_id();
  2915. struct rq *rq = cpu_rq(cpu);
  2916. struct task_struct *curr = rq->curr;
  2917. sched_clock_tick();
  2918. raw_spin_lock(&rq->lock);
  2919. update_rq_clock(rq);
  2920. update_cpu_load(rq);
  2921. curr->sched_class->task_tick(rq, curr, 0);
  2922. raw_spin_unlock(&rq->lock);
  2923. perf_event_task_tick(curr);
  2924. #ifdef CONFIG_SMP
  2925. rq->idle_at_tick = idle_cpu(cpu);
  2926. trigger_load_balance(rq, cpu);
  2927. #endif
  2928. }
  2929. notrace unsigned long get_parent_ip(unsigned long addr)
  2930. {
  2931. if (in_lock_functions(addr)) {
  2932. addr = CALLER_ADDR2;
  2933. if (in_lock_functions(addr))
  2934. addr = CALLER_ADDR3;
  2935. }
  2936. return addr;
  2937. }
  2938. #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
  2939. defined(CONFIG_PREEMPT_TRACER))
  2940. void __kprobes add_preempt_count(int val)
  2941. {
  2942. #ifdef CONFIG_DEBUG_PREEMPT
  2943. /*
  2944. * Underflow?
  2945. */
  2946. if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
  2947. return;
  2948. #endif
  2949. preempt_count() += val;
  2950. #ifdef CONFIG_DEBUG_PREEMPT
  2951. /*
  2952. * Spinlock count overflowing soon?
  2953. */
  2954. DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
  2955. PREEMPT_MASK - 10);
  2956. #endif
  2957. if (preempt_count() == val)
  2958. trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
  2959. }
  2960. EXPORT_SYMBOL(add_preempt_count);
  2961. void __kprobes sub_preempt_count(int val)
  2962. {
  2963. #ifdef CONFIG_DEBUG_PREEMPT
  2964. /*
  2965. * Underflow?
  2966. */
  2967. if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
  2968. return;
  2969. /*
  2970. * Is the spinlock portion underflowing?
  2971. */
  2972. if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
  2973. !(preempt_count() & PREEMPT_MASK)))
  2974. return;
  2975. #endif
  2976. if (preempt_count() == val)
  2977. trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
  2978. preempt_count() -= val;
  2979. }
  2980. EXPORT_SYMBOL(sub_preempt_count);
  2981. #endif
  2982. /*
  2983. * Print scheduling while atomic bug:
  2984. */
  2985. static noinline void __schedule_bug(struct task_struct *prev)
  2986. {
  2987. struct pt_regs *regs = get_irq_regs();
  2988. printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
  2989. prev->comm, prev->pid, preempt_count());
  2990. debug_show_held_locks(prev);
  2991. print_modules();
  2992. if (irqs_disabled())
  2993. print_irqtrace_events(prev);
  2994. if (regs)
  2995. show_regs(regs);
  2996. else
  2997. dump_stack();
  2998. }
  2999. /*
  3000. * Various schedule()-time debugging checks and statistics:
  3001. */
  3002. static inline void schedule_debug(struct task_struct *prev)
  3003. {
  3004. /*
  3005. * Test if we are atomic. Since do_exit() needs to call into
  3006. * schedule() atomically, we ignore that path for now.
  3007. * Otherwise, whine if we are scheduling when we should not be.
  3008. */
  3009. if (unlikely(in_atomic_preempt_off() && !prev->exit_state))
  3010. __schedule_bug(prev);
  3011. profile_hit(SCHED_PROFILING, __builtin_return_address(0));
  3012. schedstat_inc(this_rq(), sched_count);
  3013. #ifdef CONFIG_SCHEDSTATS
  3014. if (unlikely(prev->lock_depth >= 0)) {
  3015. schedstat_inc(this_rq(), bkl_count);
  3016. schedstat_inc(prev, sched_info.bkl_count);
  3017. }
  3018. #endif
  3019. }
  3020. static void put_prev_task(struct rq *rq, struct task_struct *prev)
  3021. {
  3022. if (prev->se.on_rq)
  3023. update_rq_clock(rq);
  3024. rq->skip_clock_update = 0;
  3025. prev->sched_class->put_prev_task(rq, prev);
  3026. }
  3027. /*
  3028. * Pick up the highest-prio task:
  3029. */
  3030. static inline struct task_struct *
  3031. pick_next_task(struct rq *rq)
  3032. {
  3033. const struct sched_class *class;
  3034. struct task_struct *p;
  3035. /*
  3036. * Optimization: we know that if all tasks are in
  3037. * the fair class we can call that function directly:
  3038. */
  3039. if (likely(rq->nr_running == rq->cfs.nr_running)) {
  3040. p = fair_sched_class.pick_next_task(rq);
  3041. if (likely(p))
  3042. return p;
  3043. }
  3044. class = sched_class_highest;
  3045. for ( ; ; ) {
  3046. p = class->pick_next_task(rq);
  3047. if (p)
  3048. return p;
  3049. /*
  3050. * Will never be NULL as the idle class always
  3051. * returns a non-NULL p:
  3052. */
  3053. class = class->next;
  3054. }
  3055. }
  3056. /*
  3057. * schedule() is the main scheduler function.
  3058. */
  3059. asmlinkage void __sched schedule(void)
  3060. {
  3061. struct task_struct *prev, *next;
  3062. unsigned long *switch_count;
  3063. struct rq *rq;
  3064. int cpu;
  3065. need_resched:
  3066. preempt_disable();
  3067. cpu = smp_processor_id();
  3068. rq = cpu_rq(cpu);
  3069. rcu_sched_qs(cpu);
  3070. prev = rq->curr;
  3071. switch_count = &prev->nivcsw;
  3072. release_kernel_lock(prev);
  3073. need_resched_nonpreemptible:
  3074. schedule_debug(prev);
  3075. if (sched_feat(HRTICK))
  3076. hrtick_clear(rq);
  3077. raw_spin_lock_irq(&rq->lock);
  3078. clear_tsk_need_resched(prev);
  3079. if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
  3080. if (unlikely(signal_pending_state(prev->state, prev)))
  3081. prev->state = TASK_RUNNING;
  3082. else
  3083. deactivate_task(rq, prev, 1);
  3084. switch_count = &prev->nvcsw;
  3085. }
  3086. pre_schedule(rq, prev);
  3087. if (unlikely(!rq->nr_running))
  3088. idle_balance(cpu, rq);
  3089. put_prev_task(rq, prev);
  3090. next = pick_next_task(rq);
  3091. if (likely(prev != next)) {
  3092. sched_info_switch(prev, next);
  3093. perf_event_task_sched_out(prev, next);
  3094. rq->nr_switches++;
  3095. rq->curr = next;
  3096. ++*switch_count;
  3097. context_switch(rq, prev, next); /* unlocks the rq */
  3098. /*
  3099. * the context switch might have flipped the stack from under
  3100. * us, hence refresh the local variables.
  3101. */
  3102. cpu = smp_processor_id();
  3103. rq = cpu_rq(cpu);
  3104. } else
  3105. raw_spin_unlock_irq(&rq->lock);
  3106. post_schedule(rq);
  3107. if (unlikely(reacquire_kernel_lock(current) < 0)) {
  3108. prev = rq->curr;
  3109. switch_count = &prev->nivcsw;
  3110. goto need_resched_nonpreemptible;
  3111. }
  3112. preempt_enable_no_resched();
  3113. if (need_resched())
  3114. goto need_resched;
  3115. }
  3116. EXPORT_SYMBOL(schedule);
  3117. #ifdef CONFIG_MUTEX_SPIN_ON_OWNER
  3118. /*
  3119. * Look out! "owner" is an entirely speculative pointer
  3120. * access and not reliable.
  3121. */
  3122. int mutex_spin_on_owner(struct mutex *lock, struct thread_info *owner)
  3123. {
  3124. unsigned int cpu;
  3125. struct rq *rq;
  3126. if (!sched_feat(OWNER_SPIN))
  3127. return 0;
  3128. #ifdef CONFIG_DEBUG_PAGEALLOC
  3129. /*
  3130. * Need to access the cpu field knowing that
  3131. * DEBUG_PAGEALLOC could have unmapped it if
  3132. * the mutex owner just released it and exited.
  3133. */
  3134. if (probe_kernel_address(&owner->cpu, cpu))
  3135. goto out;
  3136. #else
  3137. cpu = owner->cpu;
  3138. #endif
  3139. /*
  3140. * Even if the access succeeded (likely case),
  3141. * the cpu field may no longer be valid.
  3142. */
  3143. if (cpu >= nr_cpumask_bits)
  3144. goto out;
  3145. /*
  3146. * We need to validate that we can do a
  3147. * get_cpu() and that we have the percpu area.
  3148. */
  3149. if (!cpu_online(cpu))
  3150. goto out;
  3151. rq = cpu_rq(cpu);
  3152. for (;;) {
  3153. /*
  3154. * Owner changed, break to re-assess state.
  3155. */
  3156. if (lock->owner != owner)
  3157. break;
  3158. /*
  3159. * Is that owner really running on that cpu?
  3160. */
  3161. if (task_thread_info(rq->curr) != owner || need_resched())
  3162. return 0;
  3163. cpu_relax();
  3164. }
  3165. out:
  3166. return 1;
  3167. }
  3168. #endif
  3169. #ifdef CONFIG_PREEMPT
  3170. /*
  3171. * this is the entry point to schedule() from in-kernel preemption
  3172. * off of preempt_enable. Kernel preemptions off return from interrupt
  3173. * occur there and call schedule directly.
  3174. */
  3175. asmlinkage void __sched preempt_schedule(void)
  3176. {
  3177. struct thread_info *ti = current_thread_info();
  3178. /*
  3179. * If there is a non-zero preempt_count or interrupts are disabled,
  3180. * we do not want to preempt the current task. Just return..
  3181. */
  3182. if (likely(ti->preempt_count || irqs_disabled()))
  3183. return;
  3184. do {
  3185. add_preempt_count(PREEMPT_ACTIVE);
  3186. schedule();
  3187. sub_preempt_count(PREEMPT_ACTIVE);
  3188. /*
  3189. * Check again in case we missed a preemption opportunity
  3190. * between schedule and now.
  3191. */
  3192. barrier();
  3193. } while (need_resched());
  3194. }
  3195. EXPORT_SYMBOL(preempt_schedule);
  3196. /*
  3197. * this is the entry point to schedule() from kernel preemption
  3198. * off of irq context.
  3199. * Note, that this is called and return with irqs disabled. This will
  3200. * protect us against recursive calling from irq.
  3201. */
  3202. asmlinkage void __sched preempt_schedule_irq(void)
  3203. {
  3204. struct thread_info *ti = current_thread_info();
  3205. /* Catch callers which need to be fixed */
  3206. BUG_ON(ti->preempt_count || !irqs_disabled());
  3207. do {
  3208. add_preempt_count(PREEMPT_ACTIVE);
  3209. local_irq_enable();
  3210. schedule();
  3211. local_irq_disable();
  3212. sub_preempt_count(PREEMPT_ACTIVE);
  3213. /*
  3214. * Check again in case we missed a preemption opportunity
  3215. * between schedule and now.
  3216. */
  3217. barrier();
  3218. } while (need_resched());
  3219. }
  3220. #endif /* CONFIG_PREEMPT */
  3221. int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags,
  3222. void *key)
  3223. {
  3224. return try_to_wake_up(curr->private, mode, wake_flags);
  3225. }
  3226. EXPORT_SYMBOL(default_wake_function);
  3227. /*
  3228. * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
  3229. * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
  3230. * number) then we wake all the non-exclusive tasks and one exclusive task.
  3231. *
  3232. * There are circumstances in which we can try to wake a task which has already
  3233. * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
  3234. * zero in this (rare) case, and we handle it by continuing to scan the queue.
  3235. */
  3236. static void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
  3237. int nr_exclusive, int wake_flags, void *key)
  3238. {
  3239. wait_queue_t *curr, *next;
  3240. list_for_each_entry_safe(curr, next, &q->task_list, task_list) {
  3241. unsigned flags = curr->flags;
  3242. if (curr->func(curr, mode, wake_flags, key) &&
  3243. (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive)
  3244. break;
  3245. }
  3246. }
  3247. /**
  3248. * __wake_up - wake up threads blocked on a waitqueue.
  3249. * @q: the waitqueue
  3250. * @mode: which threads
  3251. * @nr_exclusive: how many wake-one or wake-many threads to wake up
  3252. * @key: is directly passed to the wakeup function
  3253. *
  3254. * It may be assumed that this function implies a write memory barrier before
  3255. * changing the task state if and only if any tasks are woken up.
  3256. */
  3257. void __wake_up(wait_queue_head_t *q, unsigned int mode,
  3258. int nr_exclusive, void *key)
  3259. {
  3260. unsigned long flags;
  3261. spin_lock_irqsave(&q->lock, flags);
  3262. __wake_up_common(q, mode, nr_exclusive, 0, key);
  3263. spin_unlock_irqrestore(&q->lock, flags);
  3264. }
  3265. EXPORT_SYMBOL(__wake_up);
  3266. /*
  3267. * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
  3268. */
  3269. void __wake_up_locked(wait_queue_head_t *q, unsigned int mode)
  3270. {
  3271. __wake_up_common(q, mode, 1, 0, NULL);
  3272. }
  3273. void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key)
  3274. {
  3275. __wake_up_common(q, mode, 1, 0, key);
  3276. }
  3277. /**
  3278. * __wake_up_sync_key - wake up threads blocked on a waitqueue.
  3279. * @q: the waitqueue
  3280. * @mode: which threads
  3281. * @nr_exclusive: how many wake-one or wake-many threads to wake up
  3282. * @key: opaque value to be passed to wakeup targets
  3283. *
  3284. * The sync wakeup differs that the waker knows that it will schedule
  3285. * away soon, so while the target thread will be woken up, it will not
  3286. * be migrated to another CPU - ie. the two threads are 'synchronized'
  3287. * with each other. This can prevent needless bouncing between CPUs.
  3288. *
  3289. * On UP it can prevent extra preemption.
  3290. *
  3291. * It may be assumed that this function implies a write memory barrier before
  3292. * changing the task state if and only if any tasks are woken up.
  3293. */
  3294. void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode,
  3295. int nr_exclusive, void *key)
  3296. {
  3297. unsigned long flags;
  3298. int wake_flags = WF_SYNC;
  3299. if (unlikely(!q))
  3300. return;
  3301. if (unlikely(!nr_exclusive))
  3302. wake_flags = 0;
  3303. spin_lock_irqsave(&q->lock, flags);
  3304. __wake_up_common(q, mode, nr_exclusive, wake_flags, key);
  3305. spin_unlock_irqrestore(&q->lock, flags);
  3306. }
  3307. EXPORT_SYMBOL_GPL(__wake_up_sync_key);
  3308. /*
  3309. * __wake_up_sync - see __wake_up_sync_key()
  3310. */
  3311. void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
  3312. {
  3313. __wake_up_sync_key(q, mode, nr_exclusive, NULL);
  3314. }
  3315. EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */
  3316. /**
  3317. * complete: - signals a single thread waiting on this completion
  3318. * @x: holds the state of this particular completion
  3319. *
  3320. * This will wake up a single thread waiting on this completion. Threads will be
  3321. * awakened in the same order in which they were queued.
  3322. *
  3323. * See also complete_all(), wait_for_completion() and related routines.
  3324. *
  3325. * It may be assumed that this function implies a write memory barrier before
  3326. * changing the task state if and only if any tasks are woken up.
  3327. */
  3328. void complete(struct completion *x)
  3329. {
  3330. unsigned long flags;
  3331. spin_lock_irqsave(&x->wait.lock, flags);
  3332. x->done++;
  3333. __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL);
  3334. spin_unlock_irqrestore(&x->wait.lock, flags);
  3335. }
  3336. EXPORT_SYMBOL(complete);
  3337. /**
  3338. * complete_all: - signals all threads waiting on this completion
  3339. * @x: holds the state of this particular completion
  3340. *
  3341. * This will wake up all threads waiting on this particular completion event.
  3342. *
  3343. * It may be assumed that this function implies a write memory barrier before
  3344. * changing the task state if and only if any tasks are woken up.
  3345. */
  3346. void complete_all(struct completion *x)
  3347. {
  3348. unsigned long flags;
  3349. spin_lock_irqsave(&x->wait.lock, flags);
  3350. x->done += UINT_MAX/2;
  3351. __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL);
  3352. spin_unlock_irqrestore(&x->wait.lock, flags);
  3353. }
  3354. EXPORT_SYMBOL(complete_all);
  3355. static inline long __sched
  3356. do_wait_for_common(struct completion *x, long timeout, int state)
  3357. {
  3358. if (!x->done) {
  3359. DECLARE_WAITQUEUE(wait, current);
  3360. wait.flags |= WQ_FLAG_EXCLUSIVE;
  3361. __add_wait_queue_tail(&x->wait, &wait);
  3362. do {
  3363. if (signal_pending_state(state, current)) {
  3364. timeout = -ERESTARTSYS;
  3365. break;
  3366. }
  3367. __set_current_state(state);
  3368. spin_unlock_irq(&x->wait.lock);
  3369. timeout = schedule_timeout(timeout);
  3370. spin_lock_irq(&x->wait.lock);
  3371. } while (!x->done && timeout);
  3372. __remove_wait_queue(&x->wait, &wait);
  3373. if (!x->done)
  3374. return timeout;
  3375. }
  3376. x->done--;
  3377. return timeout ?: 1;
  3378. }
  3379. static long __sched
  3380. wait_for_common(struct completion *x, long timeout, int state)
  3381. {
  3382. might_sleep();
  3383. spin_lock_irq(&x->wait.lock);
  3384. timeout = do_wait_for_common(x, timeout, state);
  3385. spin_unlock_irq(&x->wait.lock);
  3386. return timeout;
  3387. }
  3388. /**
  3389. * wait_for_completion: - waits for completion of a task
  3390. * @x: holds the state of this particular completion
  3391. *
  3392. * This waits to be signaled for completion of a specific task. It is NOT
  3393. * interruptible and there is no timeout.
  3394. *
  3395. * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
  3396. * and interrupt capability. Also see complete().
  3397. */
  3398. void __sched wait_for_completion(struct completion *x)
  3399. {
  3400. wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE);
  3401. }
  3402. EXPORT_SYMBOL(wait_for_completion);
  3403. /**
  3404. * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
  3405. * @x: holds the state of this particular completion
  3406. * @timeout: timeout value in jiffies
  3407. *
  3408. * This waits for either a completion of a specific task to be signaled or for a
  3409. * specified timeout to expire. The timeout is in jiffies. It is not
  3410. * interruptible.
  3411. */
  3412. unsigned long __sched
  3413. wait_for_completion_timeout(struct completion *x, unsigned long timeout)
  3414. {
  3415. return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE);
  3416. }
  3417. EXPORT_SYMBOL(wait_for_completion_timeout);
  3418. /**
  3419. * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
  3420. * @x: holds the state of this particular completion
  3421. *
  3422. * This waits for completion of a specific task to be signaled. It is
  3423. * interruptible.
  3424. */
  3425. int __sched wait_for_completion_interruptible(struct completion *x)
  3426. {
  3427. long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE);
  3428. if (t == -ERESTARTSYS)
  3429. return t;
  3430. return 0;
  3431. }
  3432. EXPORT_SYMBOL(wait_for_completion_interruptible);
  3433. /**
  3434. * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
  3435. * @x: holds the state of this particular completion
  3436. * @timeout: timeout value in jiffies
  3437. *
  3438. * This waits for either a completion of a specific task to be signaled or for a
  3439. * specified timeout to expire. It is interruptible. The timeout is in jiffies.
  3440. */
  3441. unsigned long __sched
  3442. wait_for_completion_interruptible_timeout(struct completion *x,
  3443. unsigned long timeout)
  3444. {
  3445. return wait_for_common(x, timeout, TASK_INTERRUPTIBLE);
  3446. }
  3447. EXPORT_SYMBOL(wait_for_completion_interruptible_timeout);
  3448. /**
  3449. * wait_for_completion_killable: - waits for completion of a task (killable)
  3450. * @x: holds the state of this particular completion
  3451. *
  3452. * This waits to be signaled for completion of a specific task. It can be
  3453. * interrupted by a kill signal.
  3454. */
  3455. int __sched wait_for_completion_killable(struct completion *x)
  3456. {
  3457. long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE);
  3458. if (t == -ERESTARTSYS)
  3459. return t;
  3460. return 0;
  3461. }
  3462. EXPORT_SYMBOL(wait_for_completion_killable);
  3463. /**
  3464. * try_wait_for_completion - try to decrement a completion without blocking
  3465. * @x: completion structure
  3466. *
  3467. * Returns: 0 if a decrement cannot be done without blocking
  3468. * 1 if a decrement succeeded.
  3469. *
  3470. * If a completion is being used as a counting completion,
  3471. * attempt to decrement the counter without blocking. This
  3472. * enables us to avoid waiting if the resource the completion
  3473. * is protecting is not available.
  3474. */
  3475. bool try_wait_for_completion(struct completion *x)
  3476. {
  3477. unsigned long flags;
  3478. int ret = 1;
  3479. spin_lock_irqsave(&x->wait.lock, flags);
  3480. if (!x->done)
  3481. ret = 0;
  3482. else
  3483. x->done--;
  3484. spin_unlock_irqrestore(&x->wait.lock, flags);
  3485. return ret;
  3486. }
  3487. EXPORT_SYMBOL(try_wait_for_completion);
  3488. /**
  3489. * completion_done - Test to see if a completion has any waiters
  3490. * @x: completion structure
  3491. *
  3492. * Returns: 0 if there are waiters (wait_for_completion() in progress)
  3493. * 1 if there are no waiters.
  3494. *
  3495. */
  3496. bool completion_done(struct completion *x)
  3497. {
  3498. unsigned long flags;
  3499. int ret = 1;
  3500. spin_lock_irqsave(&x->wait.lock, flags);
  3501. if (!x->done)
  3502. ret = 0;
  3503. spin_unlock_irqrestore(&x->wait.lock, flags);
  3504. return ret;
  3505. }
  3506. EXPORT_SYMBOL(completion_done);
  3507. static long __sched
  3508. sleep_on_common(wait_queue_head_t *q, int state, long timeout)
  3509. {
  3510. unsigned long flags;
  3511. wait_queue_t wait;
  3512. init_waitqueue_entry(&wait, current);
  3513. __set_current_state(state);
  3514. spin_lock_irqsave(&q->lock, flags);
  3515. __add_wait_queue(q, &wait);
  3516. spin_unlock(&q->lock);
  3517. timeout = schedule_timeout(timeout);
  3518. spin_lock_irq(&q->lock);
  3519. __remove_wait_queue(q, &wait);
  3520. spin_unlock_irqrestore(&q->lock, flags);
  3521. return timeout;
  3522. }
  3523. void __sched interruptible_sleep_on(wait_queue_head_t *q)
  3524. {
  3525. sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
  3526. }
  3527. EXPORT_SYMBOL(interruptible_sleep_on);
  3528. long __sched
  3529. interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout)
  3530. {
  3531. return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout);
  3532. }
  3533. EXPORT_SYMBOL(interruptible_sleep_on_timeout);
  3534. void __sched sleep_on(wait_queue_head_t *q)
  3535. {
  3536. sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
  3537. }
  3538. EXPORT_SYMBOL(sleep_on);
  3539. long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout)
  3540. {
  3541. return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout);
  3542. }
  3543. EXPORT_SYMBOL(sleep_on_timeout);
  3544. #ifdef CONFIG_RT_MUTEXES
  3545. /*
  3546. * rt_mutex_setprio - set the current priority of a task
  3547. * @p: task
  3548. * @prio: prio value (kernel-internal form)
  3549. *
  3550. * This function changes the 'effective' priority of a task. It does
  3551. * not touch ->normal_prio like __setscheduler().
  3552. *
  3553. * Used by the rt_mutex code to implement priority inheritance logic.
  3554. */
  3555. void rt_mutex_setprio(struct task_struct *p, int prio)
  3556. {
  3557. unsigned long flags;
  3558. int oldprio, on_rq, running;
  3559. struct rq *rq;
  3560. const struct sched_class *prev_class;
  3561. BUG_ON(prio < 0 || prio > MAX_PRIO);
  3562. rq = task_rq_lock(p, &flags);
  3563. oldprio = p->prio;
  3564. prev_class = p->sched_class;
  3565. on_rq = p->se.on_rq;
  3566. running = task_current(rq, p);
  3567. if (on_rq)
  3568. dequeue_task(rq, p, 0);
  3569. if (running)
  3570. p->sched_class->put_prev_task(rq, p);
  3571. if (rt_prio(prio))
  3572. p->sched_class = &rt_sched_class;
  3573. else
  3574. p->sched_class = &fair_sched_class;
  3575. p->prio = prio;
  3576. if (running)
  3577. p->sched_class->set_curr_task(rq);
  3578. if (on_rq) {
  3579. enqueue_task(rq, p, 0, oldprio < prio);
  3580. check_class_changed(rq, p, prev_class, oldprio, running);
  3581. }
  3582. task_rq_unlock(rq, &flags);
  3583. }
  3584. #endif
  3585. void set_user_nice(struct task_struct *p, long nice)
  3586. {
  3587. int old_prio, delta, on_rq;
  3588. unsigned long flags;
  3589. struct rq *rq;
  3590. if (TASK_NICE(p) == nice || nice < -20 || nice > 19)
  3591. return;
  3592. /*
  3593. * We have to be careful, if called from sys_setpriority(),
  3594. * the task might be in the middle of scheduling on another CPU.
  3595. */
  3596. rq = task_rq_lock(p, &flags);
  3597. /*
  3598. * The RT priorities are set via sched_setscheduler(), but we still
  3599. * allow the 'normal' nice value to be set - but as expected
  3600. * it wont have any effect on scheduling until the task is
  3601. * SCHED_FIFO/SCHED_RR:
  3602. */
  3603. if (task_has_rt_policy(p)) {
  3604. p->static_prio = NICE_TO_PRIO(nice);
  3605. goto out_unlock;
  3606. }
  3607. on_rq = p->se.on_rq;
  3608. if (on_rq)
  3609. dequeue_task(rq, p, 0);
  3610. p->static_prio = NICE_TO_PRIO(nice);
  3611. set_load_weight(p);
  3612. old_prio = p->prio;
  3613. p->prio = effective_prio(p);
  3614. delta = p->prio - old_prio;
  3615. if (on_rq) {
  3616. enqueue_task(rq, p, 0, false);
  3617. /*
  3618. * If the task increased its priority or is running and
  3619. * lowered its priority, then reschedule its CPU:
  3620. */
  3621. if (delta < 0 || (delta > 0 && task_running(rq, p)))
  3622. resched_task(rq->curr);
  3623. }
  3624. out_unlock:
  3625. task_rq_unlock(rq, &flags);
  3626. }
  3627. EXPORT_SYMBOL(set_user_nice);
  3628. /*
  3629. * can_nice - check if a task can reduce its nice value
  3630. * @p: task
  3631. * @nice: nice value
  3632. */
  3633. int can_nice(const struct task_struct *p, const int nice)
  3634. {
  3635. /* convert nice value [19,-20] to rlimit style value [1,40] */
  3636. int nice_rlim = 20 - nice;
  3637. return (nice_rlim <= p->signal->rlim[RLIMIT_NICE].rlim_cur ||
  3638. capable(CAP_SYS_NICE));
  3639. }
  3640. #ifdef __ARCH_WANT_SYS_NICE
  3641. /*
  3642. * sys_nice - change the priority of the current process.
  3643. * @increment: priority increment
  3644. *
  3645. * sys_setpriority is a more generic, but much slower function that
  3646. * does similar things.
  3647. */
  3648. SYSCALL_DEFINE1(nice, int, increment)
  3649. {
  3650. long nice, retval;
  3651. /*
  3652. * Setpriority might change our priority at the same moment.
  3653. * We don't have to worry. Conceptually one call occurs first
  3654. * and we have a single winner.
  3655. */
  3656. if (increment < -40)
  3657. increment = -40;
  3658. if (increment > 40)
  3659. increment = 40;
  3660. nice = TASK_NICE(current) + increment;
  3661. if (nice < -20)
  3662. nice = -20;
  3663. if (nice > 19)
  3664. nice = 19;
  3665. if (increment < 0 && !can_nice(current, nice))
  3666. return -EPERM;
  3667. retval = security_task_setnice(current, nice);
  3668. if (retval)
  3669. return retval;
  3670. set_user_nice(current, nice);
  3671. return 0;
  3672. }
  3673. #endif
  3674. /**
  3675. * task_prio - return the priority value of a given task.
  3676. * @p: the task in question.
  3677. *
  3678. * This is the priority value as seen by users in /proc.
  3679. * RT tasks are offset by -200. Normal tasks are centered
  3680. * around 0, value goes from -16 to +15.
  3681. */
  3682. int task_prio(const struct task_struct *p)
  3683. {
  3684. return p->prio - MAX_RT_PRIO;
  3685. }
  3686. /**
  3687. * task_nice - return the nice value of a given task.
  3688. * @p: the task in question.
  3689. */
  3690. int task_nice(const struct task_struct *p)
  3691. {
  3692. return TASK_NICE(p);
  3693. }
  3694. EXPORT_SYMBOL(task_nice);
  3695. /**
  3696. * idle_cpu - is a given cpu idle currently?
  3697. * @cpu: the processor in question.
  3698. */
  3699. int idle_cpu(int cpu)
  3700. {
  3701. return cpu_curr(cpu) == cpu_rq(cpu)->idle;
  3702. }
  3703. /**
  3704. * idle_task - return the idle task for a given cpu.
  3705. * @cpu: the processor in question.
  3706. */
  3707. struct task_struct *idle_task(int cpu)
  3708. {
  3709. return cpu_rq(cpu)->idle;
  3710. }
  3711. /**
  3712. * find_process_by_pid - find a process with a matching PID value.
  3713. * @pid: the pid in question.
  3714. */
  3715. static struct task_struct *find_process_by_pid(pid_t pid)
  3716. {
  3717. return pid ? find_task_by_vpid(pid) : current;
  3718. }
  3719. /* Actually do priority change: must hold rq lock. */
  3720. static void
  3721. __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio)
  3722. {
  3723. BUG_ON(p->se.on_rq);
  3724. p->policy = policy;
  3725. p->rt_priority = prio;
  3726. p->normal_prio = normal_prio(p);
  3727. /* we are holding p->pi_lock already */
  3728. p->prio = rt_mutex_getprio(p);
  3729. if (rt_prio(p->prio))
  3730. p->sched_class = &rt_sched_class;
  3731. else
  3732. p->sched_class = &fair_sched_class;
  3733. set_load_weight(p);
  3734. }
  3735. /*
  3736. * check the target process has a UID that matches the current process's
  3737. */
  3738. static bool check_same_owner(struct task_struct *p)
  3739. {
  3740. const struct cred *cred = current_cred(), *pcred;
  3741. bool match;
  3742. rcu_read_lock();
  3743. pcred = __task_cred(p);
  3744. match = (cred->euid == pcred->euid ||
  3745. cred->euid == pcred->uid);
  3746. rcu_read_unlock();
  3747. return match;
  3748. }
  3749. static int __sched_setscheduler(struct task_struct *p, int policy,
  3750. struct sched_param *param, bool user)
  3751. {
  3752. int retval, oldprio, oldpolicy = -1, on_rq, running;
  3753. unsigned long flags;
  3754. const struct sched_class *prev_class;
  3755. struct rq *rq;
  3756. int reset_on_fork;
  3757. /* may grab non-irq protected spin_locks */
  3758. BUG_ON(in_interrupt());
  3759. recheck:
  3760. /* double check policy once rq lock held */
  3761. if (policy < 0) {
  3762. reset_on_fork = p->sched_reset_on_fork;
  3763. policy = oldpolicy = p->policy;
  3764. } else {
  3765. reset_on_fork = !!(policy & SCHED_RESET_ON_FORK);
  3766. policy &= ~SCHED_RESET_ON_FORK;
  3767. if (policy != SCHED_FIFO && policy != SCHED_RR &&
  3768. policy != SCHED_NORMAL && policy != SCHED_BATCH &&
  3769. policy != SCHED_IDLE)
  3770. return -EINVAL;
  3771. }
  3772. /*
  3773. * Valid priorities for SCHED_FIFO and SCHED_RR are
  3774. * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
  3775. * SCHED_BATCH and SCHED_IDLE is 0.
  3776. */
  3777. if (param->sched_priority < 0 ||
  3778. (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) ||
  3779. (!p->mm && param->sched_priority > MAX_RT_PRIO-1))
  3780. return -EINVAL;
  3781. if (rt_policy(policy) != (param->sched_priority != 0))
  3782. return -EINVAL;
  3783. /*
  3784. * Allow unprivileged RT tasks to decrease priority:
  3785. */
  3786. if (user && !capable(CAP_SYS_NICE)) {
  3787. if (rt_policy(policy)) {
  3788. unsigned long rlim_rtprio;
  3789. if (!lock_task_sighand(p, &flags))
  3790. return -ESRCH;
  3791. rlim_rtprio = p->signal->rlim[RLIMIT_RTPRIO].rlim_cur;
  3792. unlock_task_sighand(p, &flags);
  3793. /* can't set/change the rt policy */
  3794. if (policy != p->policy && !rlim_rtprio)
  3795. return -EPERM;
  3796. /* can't increase priority */
  3797. if (param->sched_priority > p->rt_priority &&
  3798. param->sched_priority > rlim_rtprio)
  3799. return -EPERM;
  3800. }
  3801. /*
  3802. * Like positive nice levels, dont allow tasks to
  3803. * move out of SCHED_IDLE either:
  3804. */
  3805. if (p->policy == SCHED_IDLE && policy != SCHED_IDLE)
  3806. return -EPERM;
  3807. /* can't change other user's priorities */
  3808. if (!check_same_owner(p))
  3809. return -EPERM;
  3810. /* Normal users shall not reset the sched_reset_on_fork flag */
  3811. if (p->sched_reset_on_fork && !reset_on_fork)
  3812. return -EPERM;
  3813. }
  3814. if (user) {
  3815. #ifdef CONFIG_RT_GROUP_SCHED
  3816. /*
  3817. * Do not allow realtime tasks into groups that have no runtime
  3818. * assigned.
  3819. */
  3820. if (rt_bandwidth_enabled() && rt_policy(policy) &&
  3821. task_group(p)->rt_bandwidth.rt_runtime == 0)
  3822. return -EPERM;
  3823. #endif
  3824. retval = security_task_setscheduler(p, policy, param);
  3825. if (retval)
  3826. return retval;
  3827. }
  3828. /*
  3829. * make sure no PI-waiters arrive (or leave) while we are
  3830. * changing the priority of the task:
  3831. */
  3832. raw_spin_lock_irqsave(&p->pi_lock, flags);
  3833. /*
  3834. * To be able to change p->policy safely, the apropriate
  3835. * runqueue lock must be held.
  3836. */
  3837. rq = __task_rq_lock(p);
  3838. /* recheck policy now with rq lock held */
  3839. if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
  3840. policy = oldpolicy = -1;
  3841. __task_rq_unlock(rq);
  3842. raw_spin_unlock_irqrestore(&p->pi_lock, flags);
  3843. goto recheck;
  3844. }
  3845. on_rq = p->se.on_rq;
  3846. running = task_current(rq, p);
  3847. if (on_rq)
  3848. deactivate_task(rq, p, 0);
  3849. if (running)
  3850. p->sched_class->put_prev_task(rq, p);
  3851. p->sched_reset_on_fork = reset_on_fork;
  3852. oldprio = p->prio;
  3853. prev_class = p->sched_class;
  3854. __setscheduler(rq, p, policy, param->sched_priority);
  3855. if (running)
  3856. p->sched_class->set_curr_task(rq);
  3857. if (on_rq) {
  3858. activate_task(rq, p, 0);
  3859. check_class_changed(rq, p, prev_class, oldprio, running);
  3860. }
  3861. __task_rq_unlock(rq);
  3862. raw_spin_unlock_irqrestore(&p->pi_lock, flags);
  3863. rt_mutex_adjust_pi(p);
  3864. return 0;
  3865. }
  3866. /**
  3867. * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
  3868. * @p: the task in question.
  3869. * @policy: new policy.
  3870. * @param: structure containing the new RT priority.
  3871. *
  3872. * NOTE that the task may be already dead.
  3873. */
  3874. int sched_setscheduler(struct task_struct *p, int policy,
  3875. struct sched_param *param)
  3876. {
  3877. return __sched_setscheduler(p, policy, param, true);
  3878. }
  3879. EXPORT_SYMBOL_GPL(sched_setscheduler);
  3880. /**
  3881. * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
  3882. * @p: the task in question.
  3883. * @policy: new policy.
  3884. * @param: structure containing the new RT priority.
  3885. *
  3886. * Just like sched_setscheduler, only don't bother checking if the
  3887. * current context has permission. For example, this is needed in
  3888. * stop_machine(): we create temporary high priority worker threads,
  3889. * but our caller might not have that capability.
  3890. */
  3891. int sched_setscheduler_nocheck(struct task_struct *p, int policy,
  3892. struct sched_param *param)
  3893. {
  3894. return __sched_setscheduler(p, policy, param, false);
  3895. }
  3896. static int
  3897. do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
  3898. {
  3899. struct sched_param lparam;
  3900. struct task_struct *p;
  3901. int retval;
  3902. if (!param || pid < 0)
  3903. return -EINVAL;
  3904. if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
  3905. return -EFAULT;
  3906. rcu_read_lock();
  3907. retval = -ESRCH;
  3908. p = find_process_by_pid(pid);
  3909. if (p != NULL)
  3910. retval = sched_setscheduler(p, policy, &lparam);
  3911. rcu_read_unlock();
  3912. return retval;
  3913. }
  3914. /**
  3915. * sys_sched_setscheduler - set/change the scheduler policy and RT priority
  3916. * @pid: the pid in question.
  3917. * @policy: new policy.
  3918. * @param: structure containing the new RT priority.
  3919. */
  3920. SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy,
  3921. struct sched_param __user *, param)
  3922. {
  3923. /* negative values for policy are not valid */
  3924. if (policy < 0)
  3925. return -EINVAL;
  3926. return do_sched_setscheduler(pid, policy, param);
  3927. }
  3928. /**
  3929. * sys_sched_setparam - set/change the RT priority of a thread
  3930. * @pid: the pid in question.
  3931. * @param: structure containing the new RT priority.
  3932. */
  3933. SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param)
  3934. {
  3935. return do_sched_setscheduler(pid, -1, param);
  3936. }
  3937. /**
  3938. * sys_sched_getscheduler - get the policy (scheduling class) of a thread
  3939. * @pid: the pid in question.
  3940. */
  3941. SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid)
  3942. {
  3943. struct task_struct *p;
  3944. int retval;
  3945. if (pid < 0)
  3946. return -EINVAL;
  3947. retval = -ESRCH;
  3948. rcu_read_lock();
  3949. p = find_process_by_pid(pid);
  3950. if (p) {
  3951. retval = security_task_getscheduler(p);
  3952. if (!retval)
  3953. retval = p->policy
  3954. | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0);
  3955. }
  3956. rcu_read_unlock();
  3957. return retval;
  3958. }
  3959. /**
  3960. * sys_sched_getparam - get the RT priority of a thread
  3961. * @pid: the pid in question.
  3962. * @param: structure containing the RT priority.
  3963. */
  3964. SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param)
  3965. {
  3966. struct sched_param lp;
  3967. struct task_struct *p;
  3968. int retval;
  3969. if (!param || pid < 0)
  3970. return -EINVAL;
  3971. rcu_read_lock();
  3972. p = find_process_by_pid(pid);
  3973. retval = -ESRCH;
  3974. if (!p)
  3975. goto out_unlock;
  3976. retval = security_task_getscheduler(p);
  3977. if (retval)
  3978. goto out_unlock;
  3979. lp.sched_priority = p->rt_priority;
  3980. rcu_read_unlock();
  3981. /*
  3982. * This one might sleep, we cannot do it with a spinlock held ...
  3983. */
  3984. retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;
  3985. return retval;
  3986. out_unlock:
  3987. rcu_read_unlock();
  3988. return retval;
  3989. }
  3990. long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
  3991. {
  3992. cpumask_var_t cpus_allowed, new_mask;
  3993. struct task_struct *p;
  3994. int retval;
  3995. get_online_cpus();
  3996. rcu_read_lock();
  3997. p = find_process_by_pid(pid);
  3998. if (!p) {
  3999. rcu_read_unlock();
  4000. put_online_cpus();
  4001. return -ESRCH;
  4002. }
  4003. /* Prevent p going away */
  4004. get_task_struct(p);
  4005. rcu_read_unlock();
  4006. if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) {
  4007. retval = -ENOMEM;
  4008. goto out_put_task;
  4009. }
  4010. if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
  4011. retval = -ENOMEM;
  4012. goto out_free_cpus_allowed;
  4013. }
  4014. retval = -EPERM;
  4015. if (!check_same_owner(p) && !capable(CAP_SYS_NICE))
  4016. goto out_unlock;
  4017. retval = security_task_setscheduler(p, 0, NULL);
  4018. if (retval)
  4019. goto out_unlock;
  4020. cpuset_cpus_allowed(p, cpus_allowed);
  4021. cpumask_and(new_mask, in_mask, cpus_allowed);
  4022. again:
  4023. retval = set_cpus_allowed_ptr(p, new_mask);
  4024. if (!retval) {
  4025. cpuset_cpus_allowed(p, cpus_allowed);
  4026. if (!cpumask_subset(new_mask, cpus_allowed)) {
  4027. /*
  4028. * We must have raced with a concurrent cpuset
  4029. * update. Just reset the cpus_allowed to the
  4030. * cpuset's cpus_allowed
  4031. */
  4032. cpumask_copy(new_mask, cpus_allowed);
  4033. goto again;
  4034. }
  4035. }
  4036. out_unlock:
  4037. free_cpumask_var(new_mask);
  4038. out_free_cpus_allowed:
  4039. free_cpumask_var(cpus_allowed);
  4040. out_put_task:
  4041. put_task_struct(p);
  4042. put_online_cpus();
  4043. return retval;
  4044. }
  4045. static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
  4046. struct cpumask *new_mask)
  4047. {
  4048. if (len < cpumask_size())
  4049. cpumask_clear(new_mask);
  4050. else if (len > cpumask_size())
  4051. len = cpumask_size();
  4052. return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
  4053. }
  4054. /**
  4055. * sys_sched_setaffinity - set the cpu affinity of a process
  4056. * @pid: pid of the process
  4057. * @len: length in bytes of the bitmask pointed to by user_mask_ptr
  4058. * @user_mask_ptr: user-space pointer to the new cpu mask
  4059. */
  4060. SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len,
  4061. unsigned long __user *, user_mask_ptr)
  4062. {
  4063. cpumask_var_t new_mask;
  4064. int retval;
  4065. if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
  4066. return -ENOMEM;
  4067. retval = get_user_cpu_mask(user_mask_ptr, len, new_mask);
  4068. if (retval == 0)
  4069. retval = sched_setaffinity(pid, new_mask);
  4070. free_cpumask_var(new_mask);
  4071. return retval;
  4072. }
  4073. long sched_getaffinity(pid_t pid, struct cpumask *mask)
  4074. {
  4075. struct task_struct *p;
  4076. unsigned long flags;
  4077. struct rq *rq;
  4078. int retval;
  4079. get_online_cpus();
  4080. rcu_read_lock();
  4081. retval = -ESRCH;
  4082. p = find_process_by_pid(pid);
  4083. if (!p)
  4084. goto out_unlock;
  4085. retval = security_task_getscheduler(p);
  4086. if (retval)
  4087. goto out_unlock;
  4088. rq = task_rq_lock(p, &flags);
  4089. cpumask_and(mask, &p->cpus_allowed, cpu_online_mask);
  4090. task_rq_unlock(rq, &flags);
  4091. out_unlock:
  4092. rcu_read_unlock();
  4093. put_online_cpus();
  4094. return retval;
  4095. }
  4096. /**
  4097. * sys_sched_getaffinity - get the cpu affinity of a process
  4098. * @pid: pid of the process
  4099. * @len: length in bytes of the bitmask pointed to by user_mask_ptr
  4100. * @user_mask_ptr: user-space pointer to hold the current cpu mask
  4101. */
  4102. SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
  4103. unsigned long __user *, user_mask_ptr)
  4104. {
  4105. int ret;
  4106. cpumask_var_t mask;
  4107. if (len < cpumask_size())
  4108. return -EINVAL;
  4109. if (!alloc_cpumask_var(&mask, GFP_KERNEL))
  4110. return -ENOMEM;
  4111. ret = sched_getaffinity(pid, mask);
  4112. if (ret == 0) {
  4113. if (copy_to_user(user_mask_ptr, mask, cpumask_size()))
  4114. ret = -EFAULT;
  4115. else
  4116. ret = cpumask_size();
  4117. }
  4118. free_cpumask_var(mask);
  4119. return ret;
  4120. }
  4121. /**
  4122. * sys_sched_yield - yield the current processor to other threads.
  4123. *
  4124. * This function yields the current CPU to other tasks. If there are no
  4125. * other threads running on this CPU then this function will return.
  4126. */
  4127. SYSCALL_DEFINE0(sched_yield)
  4128. {
  4129. struct rq *rq = this_rq_lock();
  4130. schedstat_inc(rq, yld_count);
  4131. current->sched_class->yield_task(rq);
  4132. /*
  4133. * Since we are going to call schedule() anyway, there's
  4134. * no need to preempt or enable interrupts:
  4135. */
  4136. __release(rq->lock);
  4137. spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
  4138. do_raw_spin_unlock(&rq->lock);
  4139. preempt_enable_no_resched();
  4140. schedule();
  4141. return 0;
  4142. }
  4143. static inline int should_resched(void)
  4144. {
  4145. return need_resched() && !(preempt_count() & PREEMPT_ACTIVE);
  4146. }
  4147. static void __cond_resched(void)
  4148. {
  4149. add_preempt_count(PREEMPT_ACTIVE);
  4150. schedule();
  4151. sub_preempt_count(PREEMPT_ACTIVE);
  4152. }
  4153. int __sched _cond_resched(void)
  4154. {
  4155. if (should_resched()) {
  4156. __cond_resched();
  4157. return 1;
  4158. }
  4159. return 0;
  4160. }
  4161. EXPORT_SYMBOL(_cond_resched);
  4162. /*
  4163. * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
  4164. * call schedule, and on return reacquire the lock.
  4165. *
  4166. * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
  4167. * operations here to prevent schedule() from being called twice (once via
  4168. * spin_unlock(), once by hand).
  4169. */
  4170. int __cond_resched_lock(spinlock_t *lock)
  4171. {
  4172. int resched = should_resched();
  4173. int ret = 0;
  4174. lockdep_assert_held(lock);
  4175. if (spin_needbreak(lock) || resched) {
  4176. spin_unlock(lock);
  4177. if (resched)
  4178. __cond_resched();
  4179. else
  4180. cpu_relax();
  4181. ret = 1;
  4182. spin_lock(lock);
  4183. }
  4184. return ret;
  4185. }
  4186. EXPORT_SYMBOL(__cond_resched_lock);
  4187. int __sched __cond_resched_softirq(void)
  4188. {
  4189. BUG_ON(!in_softirq());
  4190. if (should_resched()) {
  4191. local_bh_enable();
  4192. __cond_resched();
  4193. local_bh_disable();
  4194. return 1;
  4195. }
  4196. return 0;
  4197. }
  4198. EXPORT_SYMBOL(__cond_resched_softirq);
  4199. /**
  4200. * yield - yield the current processor to other threads.
  4201. *
  4202. * This is a shortcut for kernel-space yielding - it marks the
  4203. * thread runnable and calls sys_sched_yield().
  4204. */
  4205. void __sched yield(void)
  4206. {
  4207. set_current_state(TASK_RUNNING);
  4208. sys_sched_yield();
  4209. }
  4210. EXPORT_SYMBOL(yield);
  4211. /*
  4212. * This task is about to go to sleep on IO. Increment rq->nr_iowait so
  4213. * that process accounting knows that this is a task in IO wait state.
  4214. */
  4215. void __sched io_schedule(void)
  4216. {
  4217. struct rq *rq = raw_rq();
  4218. delayacct_blkio_start();
  4219. atomic_inc(&rq->nr_iowait);
  4220. current->in_iowait = 1;
  4221. schedule();
  4222. current->in_iowait = 0;
  4223. atomic_dec(&rq->nr_iowait);
  4224. delayacct_blkio_end();
  4225. }
  4226. EXPORT_SYMBOL(io_schedule);
  4227. long __sched io_schedule_timeout(long timeout)
  4228. {
  4229. struct rq *rq = raw_rq();
  4230. long ret;
  4231. delayacct_blkio_start();
  4232. atomic_inc(&rq->nr_iowait);
  4233. current->in_iowait = 1;
  4234. ret = schedule_timeout(timeout);
  4235. current->in_iowait = 0;
  4236. atomic_dec(&rq->nr_iowait);
  4237. delayacct_blkio_end();
  4238. return ret;
  4239. }
  4240. /**
  4241. * sys_sched_get_priority_max - return maximum RT priority.
  4242. * @policy: scheduling class.
  4243. *
  4244. * this syscall returns the maximum rt_priority that can be used
  4245. * by a given scheduling class.
  4246. */
  4247. SYSCALL_DEFINE1(sched_get_priority_max, int, policy)
  4248. {
  4249. int ret = -EINVAL;
  4250. switch (policy) {
  4251. case SCHED_FIFO:
  4252. case SCHED_RR:
  4253. ret = MAX_USER_RT_PRIO-1;
  4254. break;
  4255. case SCHED_NORMAL:
  4256. case SCHED_BATCH:
  4257. case SCHED_IDLE:
  4258. ret = 0;
  4259. break;
  4260. }
  4261. return ret;
  4262. }
  4263. /**
  4264. * sys_sched_get_priority_min - return minimum RT priority.
  4265. * @policy: scheduling class.
  4266. *
  4267. * this syscall returns the minimum rt_priority that can be used
  4268. * by a given scheduling class.
  4269. */
  4270. SYSCALL_DEFINE1(sched_get_priority_min, int, policy)
  4271. {
  4272. int ret = -EINVAL;
  4273. switch (policy) {
  4274. case SCHED_FIFO:
  4275. case SCHED_RR:
  4276. ret = 1;
  4277. break;
  4278. case SCHED_NORMAL:
  4279. case SCHED_BATCH:
  4280. case SCHED_IDLE:
  4281. ret = 0;
  4282. }
  4283. return ret;
  4284. }
  4285. /**
  4286. * sys_sched_rr_get_interval - return the default timeslice of a process.
  4287. * @pid: pid of the process.
  4288. * @interval: userspace pointer to the timeslice value.
  4289. *
  4290. * this syscall writes the default timeslice value of a given process
  4291. * into the user-space timespec buffer. A value of '0' means infinity.
  4292. */
  4293. SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid,
  4294. struct timespec __user *, interval)
  4295. {
  4296. struct task_struct *p;
  4297. unsigned int time_slice;
  4298. unsigned long flags;
  4299. struct rq *rq;
  4300. int retval;
  4301. struct timespec t;
  4302. if (pid < 0)
  4303. return -EINVAL;
  4304. retval = -ESRCH;
  4305. rcu_read_lock();
  4306. p = find_process_by_pid(pid);
  4307. if (!p)
  4308. goto out_unlock;
  4309. retval = security_task_getscheduler(p);
  4310. if (retval)
  4311. goto out_unlock;
  4312. rq = task_rq_lock(p, &flags);
  4313. time_slice = p->sched_class->get_rr_interval(rq, p);
  4314. task_rq_unlock(rq, &flags);
  4315. rcu_read_unlock();
  4316. jiffies_to_timespec(time_slice, &t);
  4317. retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;
  4318. return retval;
  4319. out_unlock:
  4320. rcu_read_unlock();
  4321. return retval;
  4322. }
  4323. static const char stat_nam[] = TASK_STATE_TO_CHAR_STR;
  4324. void sched_show_task(struct task_struct *p)
  4325. {
  4326. unsigned long free = 0;
  4327. unsigned state;
  4328. state = p->state ? __ffs(p->state) + 1 : 0;
  4329. printk(KERN_INFO "%-13.13s %c", p->comm,
  4330. state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?');
  4331. #if BITS_PER_LONG == 32
  4332. if (state == TASK_RUNNING)
  4333. printk(KERN_CONT " running ");
  4334. else
  4335. printk(KERN_CONT " %08lx ", thread_saved_pc(p));
  4336. #else
  4337. if (state == TASK_RUNNING)
  4338. printk(KERN_CONT " running task ");
  4339. else
  4340. printk(KERN_CONT " %016lx ", thread_saved_pc(p));
  4341. #endif
  4342. #ifdef CONFIG_DEBUG_STACK_USAGE
  4343. free = stack_not_used(p);
  4344. #endif
  4345. printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free,
  4346. task_pid_nr(p), task_pid_nr(p->real_parent),
  4347. (unsigned long)task_thread_info(p)->flags);
  4348. show_stack(p, NULL);
  4349. }
  4350. void show_state_filter(unsigned long state_filter)
  4351. {
  4352. struct task_struct *g, *p;
  4353. #if BITS_PER_LONG == 32
  4354. printk(KERN_INFO
  4355. " task PC stack pid father\n");
  4356. #else
  4357. printk(KERN_INFO
  4358. " task PC stack pid father\n");
  4359. #endif
  4360. read_lock(&tasklist_lock);
  4361. do_each_thread(g, p) {
  4362. /*
  4363. * reset the NMI-timeout, listing all files on a slow
  4364. * console might take alot of time:
  4365. */
  4366. touch_nmi_watchdog();
  4367. if (!state_filter || (p->state & state_filter))
  4368. sched_show_task(p);
  4369. } while_each_thread(g, p);
  4370. touch_all_softlockup_watchdogs();
  4371. #ifdef CONFIG_SCHED_DEBUG
  4372. sysrq_sched_debug_show();
  4373. #endif
  4374. read_unlock(&tasklist_lock);
  4375. /*
  4376. * Only show locks if all tasks are dumped:
  4377. */
  4378. if (!state_filter)
  4379. debug_show_all_locks();
  4380. }
  4381. void __cpuinit init_idle_bootup_task(struct task_struct *idle)
  4382. {
  4383. idle->sched_class = &idle_sched_class;
  4384. }
  4385. /**
  4386. * init_idle - set up an idle thread for a given CPU
  4387. * @idle: task in question
  4388. * @cpu: cpu the idle task belongs to
  4389. *
  4390. * NOTE: this function does not set the idle thread's NEED_RESCHED
  4391. * flag, to make booting more robust.
  4392. */
  4393. void __cpuinit init_idle(struct task_struct *idle, int cpu)
  4394. {
  4395. struct rq *rq = cpu_rq(cpu);
  4396. unsigned long flags;
  4397. raw_spin_lock_irqsave(&rq->lock, flags);
  4398. __sched_fork(idle);
  4399. idle->state = TASK_RUNNING;
  4400. idle->se.exec_start = sched_clock();
  4401. cpumask_copy(&idle->cpus_allowed, cpumask_of(cpu));
  4402. __set_task_cpu(idle, cpu);
  4403. rq->curr = rq->idle = idle;
  4404. #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
  4405. idle->oncpu = 1;
  4406. #endif
  4407. raw_spin_unlock_irqrestore(&rq->lock, flags);
  4408. /* Set the preempt count _outside_ the spinlocks! */
  4409. #if defined(CONFIG_PREEMPT)
  4410. task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0);
  4411. #else
  4412. task_thread_info(idle)->preempt_count = 0;
  4413. #endif
  4414. /*
  4415. * The idle tasks have their own, simple scheduling class:
  4416. */
  4417. idle->sched_class = &idle_sched_class;
  4418. ftrace_graph_init_task(idle);
  4419. }
  4420. /*
  4421. * In a system that switches off the HZ timer nohz_cpu_mask
  4422. * indicates which cpus entered this state. This is used
  4423. * in the rcu update to wait only for active cpus. For system
  4424. * which do not switch off the HZ timer nohz_cpu_mask should
  4425. * always be CPU_BITS_NONE.
  4426. */
  4427. cpumask_var_t nohz_cpu_mask;
  4428. /*
  4429. * Increase the granularity value when there are more CPUs,
  4430. * because with more CPUs the 'effective latency' as visible
  4431. * to users decreases. But the relationship is not linear,
  4432. * so pick a second-best guess by going with the log2 of the
  4433. * number of CPUs.
  4434. *
  4435. * This idea comes from the SD scheduler of Con Kolivas:
  4436. */
  4437. static int get_update_sysctl_factor(void)
  4438. {
  4439. unsigned int cpus = min_t(int, num_online_cpus(), 8);
  4440. unsigned int factor;
  4441. switch (sysctl_sched_tunable_scaling) {
  4442. case SCHED_TUNABLESCALING_NONE:
  4443. factor = 1;
  4444. break;
  4445. case SCHED_TUNABLESCALING_LINEAR:
  4446. factor = cpus;
  4447. break;
  4448. case SCHED_TUNABLESCALING_LOG:
  4449. default:
  4450. factor = 1 + ilog2(cpus);
  4451. break;
  4452. }
  4453. return factor;
  4454. }
  4455. static void update_sysctl(void)
  4456. {
  4457. unsigned int factor = get_update_sysctl_factor();
  4458. #define SET_SYSCTL(name) \
  4459. (sysctl_##name = (factor) * normalized_sysctl_##name)
  4460. SET_SYSCTL(sched_min_granularity);
  4461. SET_SYSCTL(sched_latency);
  4462. SET_SYSCTL(sched_wakeup_granularity);
  4463. SET_SYSCTL(sched_shares_ratelimit);
  4464. #undef SET_SYSCTL
  4465. }
  4466. static inline void sched_init_granularity(void)
  4467. {
  4468. update_sysctl();
  4469. }
  4470. #ifdef CONFIG_SMP
  4471. /*
  4472. * This is how migration works:
  4473. *
  4474. * 1) we queue a struct migration_req structure in the source CPU's
  4475. * runqueue and wake up that CPU's migration thread.
  4476. * 2) we down() the locked semaphore => thread blocks.
  4477. * 3) migration thread wakes up (implicitly it forces the migrated
  4478. * thread off the CPU)
  4479. * 4) it gets the migration request and checks whether the migrated
  4480. * task is still in the wrong runqueue.
  4481. * 5) if it's in the wrong runqueue then the migration thread removes
  4482. * it and puts it into the right queue.
  4483. * 6) migration thread up()s the semaphore.
  4484. * 7) we wake up and the migration is done.
  4485. */
  4486. /*
  4487. * Change a given task's CPU affinity. Migrate the thread to a
  4488. * proper CPU and schedule it away if the CPU it's executing on
  4489. * is removed from the allowed bitmask.
  4490. *
  4491. * NOTE: the caller must have a valid reference to the task, the
  4492. * task must not exit() & deallocate itself prematurely. The
  4493. * call is not atomic; no spinlocks may be held.
  4494. */
  4495. int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
  4496. {
  4497. struct migration_req req;
  4498. unsigned long flags;
  4499. struct rq *rq;
  4500. int ret = 0;
  4501. rq = task_rq_lock(p, &flags);
  4502. if (!cpumask_intersects(new_mask, cpu_active_mask)) {
  4503. ret = -EINVAL;
  4504. goto out;
  4505. }
  4506. if (unlikely((p->flags & PF_THREAD_BOUND) && p != current &&
  4507. !cpumask_equal(&p->cpus_allowed, new_mask))) {
  4508. ret = -EINVAL;
  4509. goto out;
  4510. }
  4511. if (p->sched_class->set_cpus_allowed)
  4512. p->sched_class->set_cpus_allowed(p, new_mask);
  4513. else {
  4514. cpumask_copy(&p->cpus_allowed, new_mask);
  4515. p->rt.nr_cpus_allowed = cpumask_weight(new_mask);
  4516. }
  4517. /* Can the task run on the task's current CPU? If so, we're done */
  4518. if (cpumask_test_cpu(task_cpu(p), new_mask))
  4519. goto out;
  4520. if (migrate_task(p, cpumask_any_and(cpu_active_mask, new_mask), &req)) {
  4521. /* Need help from migration thread: drop lock and wait. */
  4522. struct task_struct *mt = rq->migration_thread;
  4523. get_task_struct(mt);
  4524. task_rq_unlock(rq, &flags);
  4525. wake_up_process(rq->migration_thread);
  4526. put_task_struct(mt);
  4527. wait_for_completion(&req.done);
  4528. tlb_migrate_finish(p->mm);
  4529. return 0;
  4530. }
  4531. out:
  4532. task_rq_unlock(rq, &flags);
  4533. return ret;
  4534. }
  4535. EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
  4536. /*
  4537. * Move (not current) task off this cpu, onto dest cpu. We're doing
  4538. * this because either it can't run here any more (set_cpus_allowed()
  4539. * away from this CPU, or CPU going down), or because we're
  4540. * attempting to rebalance this task on exec (sched_exec).
  4541. *
  4542. * So we race with normal scheduler movements, but that's OK, as long
  4543. * as the task is no longer on this CPU.
  4544. *
  4545. * Returns non-zero if task was successfully migrated.
  4546. */
  4547. static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
  4548. {
  4549. struct rq *rq_dest, *rq_src;
  4550. int ret = 0;
  4551. if (unlikely(!cpu_active(dest_cpu)))
  4552. return ret;
  4553. rq_src = cpu_rq(src_cpu);
  4554. rq_dest = cpu_rq(dest_cpu);
  4555. double_rq_lock(rq_src, rq_dest);
  4556. /* Already moved. */
  4557. if (task_cpu(p) != src_cpu)
  4558. goto done;
  4559. /* Affinity changed (again). */
  4560. if (!cpumask_test_cpu(dest_cpu, &p->cpus_allowed))
  4561. goto fail;
  4562. /*
  4563. * If we're not on a rq, the next wake-up will ensure we're
  4564. * placed properly.
  4565. */
  4566. if (p->se.on_rq) {
  4567. deactivate_task(rq_src, p, 0);
  4568. set_task_cpu(p, dest_cpu);
  4569. activate_task(rq_dest, p, 0);
  4570. check_preempt_curr(rq_dest, p, 0);
  4571. }
  4572. done:
  4573. ret = 1;
  4574. fail:
  4575. double_rq_unlock(rq_src, rq_dest);
  4576. return ret;
  4577. }
  4578. #define RCU_MIGRATION_IDLE 0
  4579. #define RCU_MIGRATION_NEED_QS 1
  4580. #define RCU_MIGRATION_GOT_QS 2
  4581. #define RCU_MIGRATION_MUST_SYNC 3
  4582. /*
  4583. * migration_thread - this is a highprio system thread that performs
  4584. * thread migration by bumping thread off CPU then 'pushing' onto
  4585. * another runqueue.
  4586. */
  4587. static int migration_thread(void *data)
  4588. {
  4589. int badcpu;
  4590. int cpu = (long)data;
  4591. struct rq *rq;
  4592. rq = cpu_rq(cpu);
  4593. BUG_ON(rq->migration_thread != current);
  4594. set_current_state(TASK_INTERRUPTIBLE);
  4595. while (!kthread_should_stop()) {
  4596. struct migration_req *req;
  4597. struct list_head *head;
  4598. raw_spin_lock_irq(&rq->lock);
  4599. if (cpu_is_offline(cpu)) {
  4600. raw_spin_unlock_irq(&rq->lock);
  4601. break;
  4602. }
  4603. if (rq->active_balance) {
  4604. active_load_balance(rq, cpu);
  4605. rq->active_balance = 0;
  4606. }
  4607. head = &rq->migration_queue;
  4608. if (list_empty(head)) {
  4609. raw_spin_unlock_irq(&rq->lock);
  4610. schedule();
  4611. set_current_state(TASK_INTERRUPTIBLE);
  4612. continue;
  4613. }
  4614. req = list_entry(head->next, struct migration_req, list);
  4615. list_del_init(head->next);
  4616. if (req->task != NULL) {
  4617. raw_spin_unlock(&rq->lock);
  4618. __migrate_task(req->task, cpu, req->dest_cpu);
  4619. } else if (likely(cpu == (badcpu = smp_processor_id()))) {
  4620. req->dest_cpu = RCU_MIGRATION_GOT_QS;
  4621. raw_spin_unlock(&rq->lock);
  4622. } else {
  4623. req->dest_cpu = RCU_MIGRATION_MUST_SYNC;
  4624. raw_spin_unlock(&rq->lock);
  4625. WARN_ONCE(1, "migration_thread() on CPU %d, expected %d\n", badcpu, cpu);
  4626. }
  4627. local_irq_enable();
  4628. complete(&req->done);
  4629. }
  4630. __set_current_state(TASK_RUNNING);
  4631. return 0;
  4632. }
  4633. #ifdef CONFIG_HOTPLUG_CPU
  4634. static int __migrate_task_irq(struct task_struct *p, int src_cpu, int dest_cpu)
  4635. {
  4636. int ret;
  4637. local_irq_disable();
  4638. ret = __migrate_task(p, src_cpu, dest_cpu);
  4639. local_irq_enable();
  4640. return ret;
  4641. }
  4642. /*
  4643. * Figure out where task on dead CPU should go, use force if necessary.
  4644. */
  4645. static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p)
  4646. {
  4647. int dest_cpu;
  4648. again:
  4649. dest_cpu = select_fallback_rq(dead_cpu, p);
  4650. /* It can have affinity changed while we were choosing. */
  4651. if (unlikely(!__migrate_task_irq(p, dead_cpu, dest_cpu)))
  4652. goto again;
  4653. }
  4654. /*
  4655. * While a dead CPU has no uninterruptible tasks queued at this point,
  4656. * it might still have a nonzero ->nr_uninterruptible counter, because
  4657. * for performance reasons the counter is not stricly tracking tasks to
  4658. * their home CPUs. So we just add the counter to another CPU's counter,
  4659. * to keep the global sum constant after CPU-down:
  4660. */
  4661. static void migrate_nr_uninterruptible(struct rq *rq_src)
  4662. {
  4663. struct rq *rq_dest = cpu_rq(cpumask_any(cpu_active_mask));
  4664. unsigned long flags;
  4665. local_irq_save(flags);
  4666. double_rq_lock(rq_src, rq_dest);
  4667. rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible;
  4668. rq_src->nr_uninterruptible = 0;
  4669. double_rq_unlock(rq_src, rq_dest);
  4670. local_irq_restore(flags);
  4671. }
  4672. /* Run through task list and migrate tasks from the dead cpu. */
  4673. static void migrate_live_tasks(int src_cpu)
  4674. {
  4675. struct task_struct *p, *t;
  4676. read_lock(&tasklist_lock);
  4677. do_each_thread(t, p) {
  4678. if (p == current)
  4679. continue;
  4680. if (task_cpu(p) == src_cpu)
  4681. move_task_off_dead_cpu(src_cpu, p);
  4682. } while_each_thread(t, p);
  4683. read_unlock(&tasklist_lock);
  4684. }
  4685. /*
  4686. * Schedules idle task to be the next runnable task on current CPU.
  4687. * It does so by boosting its priority to highest possible.
  4688. * Used by CPU offline code.
  4689. */
  4690. void sched_idle_next(void)
  4691. {
  4692. int this_cpu = smp_processor_id();
  4693. struct rq *rq = cpu_rq(this_cpu);
  4694. struct task_struct *p = rq->idle;
  4695. unsigned long flags;
  4696. /* cpu has to be offline */
  4697. BUG_ON(cpu_online(this_cpu));
  4698. /*
  4699. * Strictly not necessary since rest of the CPUs are stopped by now
  4700. * and interrupts disabled on the current cpu.
  4701. */
  4702. raw_spin_lock_irqsave(&rq->lock, flags);
  4703. __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
  4704. activate_task(rq, p, 0);
  4705. raw_spin_unlock_irqrestore(&rq->lock, flags);
  4706. }
  4707. /*
  4708. * Ensures that the idle task is using init_mm right before its cpu goes
  4709. * offline.
  4710. */
  4711. void idle_task_exit(void)
  4712. {
  4713. struct mm_struct *mm = current->active_mm;
  4714. BUG_ON(cpu_online(smp_processor_id()));
  4715. if (mm != &init_mm)
  4716. switch_mm(mm, &init_mm, current);
  4717. mmdrop(mm);
  4718. }
  4719. /* called under rq->lock with disabled interrupts */
  4720. static void migrate_dead(unsigned int dead_cpu, struct task_struct *p)
  4721. {
  4722. struct rq *rq = cpu_rq(dead_cpu);
  4723. /* Must be exiting, otherwise would be on tasklist. */
  4724. BUG_ON(!p->exit_state);
  4725. /* Cannot have done final schedule yet: would have vanished. */
  4726. BUG_ON(p->state == TASK_DEAD);
  4727. get_task_struct(p);
  4728. /*
  4729. * Drop lock around migration; if someone else moves it,
  4730. * that's OK. No task can be added to this CPU, so iteration is
  4731. * fine.
  4732. */
  4733. raw_spin_unlock_irq(&rq->lock);
  4734. move_task_off_dead_cpu(dead_cpu, p);
  4735. raw_spin_lock_irq(&rq->lock);
  4736. put_task_struct(p);
  4737. }
  4738. /* release_task() removes task from tasklist, so we won't find dead tasks. */
  4739. static void migrate_dead_tasks(unsigned int dead_cpu)
  4740. {
  4741. struct rq *rq = cpu_rq(dead_cpu);
  4742. struct task_struct *next;
  4743. for ( ; ; ) {
  4744. if (!rq->nr_running)
  4745. break;
  4746. next = pick_next_task(rq);
  4747. if (!next)
  4748. break;
  4749. next->sched_class->put_prev_task(rq, next);
  4750. migrate_dead(dead_cpu, next);
  4751. }
  4752. }
  4753. /*
  4754. * remove the tasks which were accounted by rq from calc_load_tasks.
  4755. */
  4756. static void calc_global_load_remove(struct rq *rq)
  4757. {
  4758. atomic_long_sub(rq->calc_load_active, &calc_load_tasks);
  4759. rq->calc_load_active = 0;
  4760. }
  4761. #endif /* CONFIG_HOTPLUG_CPU */
  4762. #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
  4763. static struct ctl_table sd_ctl_dir[] = {
  4764. {
  4765. .procname = "sched_domain",
  4766. .mode = 0555,
  4767. },
  4768. {}
  4769. };
  4770. static struct ctl_table sd_ctl_root[] = {
  4771. {
  4772. .procname = "kernel",
  4773. .mode = 0555,
  4774. .child = sd_ctl_dir,
  4775. },
  4776. {}
  4777. };
  4778. static struct ctl_table *sd_alloc_ctl_entry(int n)
  4779. {
  4780. struct ctl_table *entry =
  4781. kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL);
  4782. return entry;
  4783. }
  4784. static void sd_free_ctl_entry(struct ctl_table **tablep)
  4785. {
  4786. struct ctl_table *entry;
  4787. /*
  4788. * In the intermediate directories, both the child directory and
  4789. * procname are dynamically allocated and could fail but the mode
  4790. * will always be set. In the lowest directory the names are
  4791. * static strings and all have proc handlers.
  4792. */
  4793. for (entry = *tablep; entry->mode; entry++) {
  4794. if (entry->child)
  4795. sd_free_ctl_entry(&entry->child);
  4796. if (entry->proc_handler == NULL)
  4797. kfree(entry->procname);
  4798. }
  4799. kfree(*tablep);
  4800. *tablep = NULL;
  4801. }
  4802. static void
  4803. set_table_entry(struct ctl_table *entry,
  4804. const char *procname, void *data, int maxlen,
  4805. mode_t mode, proc_handler *proc_handler)
  4806. {
  4807. entry->procname = procname;
  4808. entry->data = data;
  4809. entry->maxlen = maxlen;
  4810. entry->mode = mode;
  4811. entry->proc_handler = proc_handler;
  4812. }
  4813. static struct ctl_table *
  4814. sd_alloc_ctl_domain_table(struct sched_domain *sd)
  4815. {
  4816. struct ctl_table *table = sd_alloc_ctl_entry(13);
  4817. if (table == NULL)
  4818. return NULL;
  4819. set_table_entry(&table[0], "min_interval", &sd->min_interval,
  4820. sizeof(long), 0644, proc_doulongvec_minmax);
  4821. set_table_entry(&table[1], "max_interval", &sd->max_interval,
  4822. sizeof(long), 0644, proc_doulongvec_minmax);
  4823. set_table_entry(&table[2], "busy_idx", &sd->busy_idx,
  4824. sizeof(int), 0644, proc_dointvec_minmax);
  4825. set_table_entry(&table[3], "idle_idx", &sd->idle_idx,
  4826. sizeof(int), 0644, proc_dointvec_minmax);
  4827. set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx,
  4828. sizeof(int), 0644, proc_dointvec_minmax);
  4829. set_table_entry(&table[5], "wake_idx", &sd->wake_idx,
  4830. sizeof(int), 0644, proc_dointvec_minmax);
  4831. set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx,
  4832. sizeof(int), 0644, proc_dointvec_minmax);
  4833. set_table_entry(&table[7], "busy_factor", &sd->busy_factor,
  4834. sizeof(int), 0644, proc_dointvec_minmax);
  4835. set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct,
  4836. sizeof(int), 0644, proc_dointvec_minmax);
  4837. set_table_entry(&table[9], "cache_nice_tries",
  4838. &sd->cache_nice_tries,
  4839. sizeof(int), 0644, proc_dointvec_minmax);
  4840. set_table_entry(&table[10], "flags", &sd->flags,
  4841. sizeof(int), 0644, proc_dointvec_minmax);
  4842. set_table_entry(&table[11], "name", sd->name,
  4843. CORENAME_MAX_SIZE, 0444, proc_dostring);
  4844. /* &table[12] is terminator */
  4845. return table;
  4846. }
  4847. static ctl_table *sd_alloc_ctl_cpu_table(int cpu)
  4848. {
  4849. struct ctl_table *entry, *table;
  4850. struct sched_domain *sd;
  4851. int domain_num = 0, i;
  4852. char buf[32];
  4853. for_each_domain(cpu, sd)
  4854. domain_num++;
  4855. entry = table = sd_alloc_ctl_entry(domain_num + 1);
  4856. if (table == NULL)
  4857. return NULL;
  4858. i = 0;
  4859. for_each_domain(cpu, sd) {
  4860. snprintf(buf, 32, "domain%d", i);
  4861. entry->procname = kstrdup(buf, GFP_KERNEL);
  4862. entry->mode = 0555;
  4863. entry->child = sd_alloc_ctl_domain_table(sd);
  4864. entry++;
  4865. i++;
  4866. }
  4867. return table;
  4868. }
  4869. static struct ctl_table_header *sd_sysctl_header;
  4870. static void register_sched_domain_sysctl(void)
  4871. {
  4872. int i, cpu_num = num_possible_cpus();
  4873. struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1);
  4874. char buf[32];
  4875. WARN_ON(sd_ctl_dir[0].child);
  4876. sd_ctl_dir[0].child = entry;
  4877. if (entry == NULL)
  4878. return;
  4879. for_each_possible_cpu(i) {
  4880. snprintf(buf, 32, "cpu%d", i);
  4881. entry->procname = kstrdup(buf, GFP_KERNEL);
  4882. entry->mode = 0555;
  4883. entry->child = sd_alloc_ctl_cpu_table(i);
  4884. entry++;
  4885. }
  4886. WARN_ON(sd_sysctl_header);
  4887. sd_sysctl_header = register_sysctl_table(sd_ctl_root);
  4888. }
  4889. /* may be called multiple times per register */
  4890. static void unregister_sched_domain_sysctl(void)
  4891. {
  4892. if (sd_sysctl_header)
  4893. unregister_sysctl_table(sd_sysctl_header);
  4894. sd_sysctl_header = NULL;
  4895. if (sd_ctl_dir[0].child)
  4896. sd_free_ctl_entry(&sd_ctl_dir[0].child);
  4897. }
  4898. #else
  4899. static void register_sched_domain_sysctl(void)
  4900. {
  4901. }
  4902. static void unregister_sched_domain_sysctl(void)
  4903. {
  4904. }
  4905. #endif
  4906. static void set_rq_online(struct rq *rq)
  4907. {
  4908. if (!rq->online) {
  4909. const struct sched_class *class;
  4910. cpumask_set_cpu(rq->cpu, rq->rd->online);
  4911. rq->online = 1;
  4912. for_each_class(class) {
  4913. if (class->rq_online)
  4914. class->rq_online(rq);
  4915. }
  4916. }
  4917. }
  4918. static void set_rq_offline(struct rq *rq)
  4919. {
  4920. if (rq->online) {
  4921. const struct sched_class *class;
  4922. for_each_class(class) {
  4923. if (class->rq_offline)
  4924. class->rq_offline(rq);
  4925. }
  4926. cpumask_clear_cpu(rq->cpu, rq->rd->online);
  4927. rq->online = 0;
  4928. }
  4929. }
  4930. /*
  4931. * migration_call - callback that gets triggered when a CPU is added.
  4932. * Here we can start up the necessary migration thread for the new CPU.
  4933. */
  4934. static int __cpuinit
  4935. migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
  4936. {
  4937. struct task_struct *p;
  4938. int cpu = (long)hcpu;
  4939. unsigned long flags;
  4940. struct rq *rq;
  4941. switch (action) {
  4942. case CPU_UP_PREPARE:
  4943. case CPU_UP_PREPARE_FROZEN:
  4944. p = kthread_create(migration_thread, hcpu, "migration/%d", cpu);
  4945. if (IS_ERR(p))
  4946. return NOTIFY_BAD;
  4947. kthread_bind(p, cpu);
  4948. /* Must be high prio: stop_machine expects to yield to it. */
  4949. rq = task_rq_lock(p, &flags);
  4950. __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
  4951. task_rq_unlock(rq, &flags);
  4952. get_task_struct(p);
  4953. cpu_rq(cpu)->migration_thread = p;
  4954. rq->calc_load_update = calc_load_update;
  4955. break;
  4956. case CPU_ONLINE:
  4957. case CPU_ONLINE_FROZEN:
  4958. /* Strictly unnecessary, as first user will wake it. */
  4959. wake_up_process(cpu_rq(cpu)->migration_thread);
  4960. /* Update our root-domain */
  4961. rq = cpu_rq(cpu);
  4962. raw_spin_lock_irqsave(&rq->lock, flags);
  4963. if (rq->rd) {
  4964. BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
  4965. set_rq_online(rq);
  4966. }
  4967. raw_spin_unlock_irqrestore(&rq->lock, flags);
  4968. break;
  4969. #ifdef CONFIG_HOTPLUG_CPU
  4970. case CPU_UP_CANCELED:
  4971. case CPU_UP_CANCELED_FROZEN:
  4972. if (!cpu_rq(cpu)->migration_thread)
  4973. break;
  4974. /* Unbind it from offline cpu so it can run. Fall thru. */
  4975. kthread_bind(cpu_rq(cpu)->migration_thread,
  4976. cpumask_any(cpu_online_mask));
  4977. kthread_stop(cpu_rq(cpu)->migration_thread);
  4978. put_task_struct(cpu_rq(cpu)->migration_thread);
  4979. cpu_rq(cpu)->migration_thread = NULL;
  4980. break;
  4981. case CPU_DEAD:
  4982. case CPU_DEAD_FROZEN:
  4983. cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */
  4984. migrate_live_tasks(cpu);
  4985. rq = cpu_rq(cpu);
  4986. kthread_stop(rq->migration_thread);
  4987. put_task_struct(rq->migration_thread);
  4988. rq->migration_thread = NULL;
  4989. /* Idle task back to normal (off runqueue, low prio) */
  4990. raw_spin_lock_irq(&rq->lock);
  4991. deactivate_task(rq, rq->idle, 0);
  4992. __setscheduler(rq, rq->idle, SCHED_NORMAL, 0);
  4993. rq->idle->sched_class = &idle_sched_class;
  4994. migrate_dead_tasks(cpu);
  4995. raw_spin_unlock_irq(&rq->lock);
  4996. cpuset_unlock();
  4997. migrate_nr_uninterruptible(rq);
  4998. BUG_ON(rq->nr_running != 0);
  4999. calc_global_load_remove(rq);
  5000. /*
  5001. * No need to migrate the tasks: it was best-effort if
  5002. * they didn't take sched_hotcpu_mutex. Just wake up
  5003. * the requestors.
  5004. */
  5005. raw_spin_lock_irq(&rq->lock);
  5006. while (!list_empty(&rq->migration_queue)) {
  5007. struct migration_req *req;
  5008. req = list_entry(rq->migration_queue.next,
  5009. struct migration_req, list);
  5010. list_del_init(&req->list);
  5011. raw_spin_unlock_irq(&rq->lock);
  5012. complete(&req->done);
  5013. raw_spin_lock_irq(&rq->lock);
  5014. }
  5015. raw_spin_unlock_irq(&rq->lock);
  5016. break;
  5017. case CPU_DYING:
  5018. case CPU_DYING_FROZEN:
  5019. /* Update our root-domain */
  5020. rq = cpu_rq(cpu);
  5021. raw_spin_lock_irqsave(&rq->lock, flags);
  5022. if (rq->rd) {
  5023. BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
  5024. set_rq_offline(rq);
  5025. }
  5026. raw_spin_unlock_irqrestore(&rq->lock, flags);
  5027. break;
  5028. #endif
  5029. }
  5030. return NOTIFY_OK;
  5031. }
  5032. /*
  5033. * Register at high priority so that task migration (migrate_all_tasks)
  5034. * happens before everything else. This has to be lower priority than
  5035. * the notifier in the perf_event subsystem, though.
  5036. */
  5037. static struct notifier_block __cpuinitdata migration_notifier = {
  5038. .notifier_call = migration_call,
  5039. .priority = 10
  5040. };
  5041. static int __init migration_init(void)
  5042. {
  5043. void *cpu = (void *)(long)smp_processor_id();
  5044. int err;
  5045. /* Start one for the boot CPU: */
  5046. err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
  5047. BUG_ON(err == NOTIFY_BAD);
  5048. migration_call(&migration_notifier, CPU_ONLINE, cpu);
  5049. register_cpu_notifier(&migration_notifier);
  5050. return 0;
  5051. }
  5052. early_initcall(migration_init);
  5053. #endif
  5054. #ifdef CONFIG_SMP
  5055. #ifdef CONFIG_SCHED_DEBUG
  5056. static __read_mostly int sched_domain_debug_enabled;
  5057. static int __init sched_domain_debug_setup(char *str)
  5058. {
  5059. sched_domain_debug_enabled = 1;
  5060. return 0;
  5061. }
  5062. early_param("sched_debug", sched_domain_debug_setup);
  5063. static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
  5064. struct cpumask *groupmask)
  5065. {
  5066. struct sched_group *group = sd->groups;
  5067. char str[256];
  5068. cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd));
  5069. cpumask_clear(groupmask);
  5070. printk(KERN_DEBUG "%*s domain %d: ", level, "", level);
  5071. if (!(sd->flags & SD_LOAD_BALANCE)) {
  5072. printk("does not load-balance\n");
  5073. if (sd->parent)
  5074. printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain"
  5075. " has parent");
  5076. return -1;
  5077. }
  5078. printk(KERN_CONT "span %s level %s\n", str, sd->name);
  5079. if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) {
  5080. printk(KERN_ERR "ERROR: domain->span does not contain "
  5081. "CPU%d\n", cpu);
  5082. }
  5083. if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) {
  5084. printk(KERN_ERR "ERROR: domain->groups does not contain"
  5085. " CPU%d\n", cpu);
  5086. }
  5087. printk(KERN_DEBUG "%*s groups:", level + 1, "");
  5088. do {
  5089. if (!group) {
  5090. printk("\n");
  5091. printk(KERN_ERR "ERROR: group is NULL\n");
  5092. break;
  5093. }
  5094. if (!group->cpu_power) {
  5095. printk(KERN_CONT "\n");
  5096. printk(KERN_ERR "ERROR: domain->cpu_power not "
  5097. "set\n");
  5098. break;
  5099. }
  5100. if (!cpumask_weight(sched_group_cpus(group))) {
  5101. printk(KERN_CONT "\n");
  5102. printk(KERN_ERR "ERROR: empty group\n");
  5103. break;
  5104. }
  5105. if (cpumask_intersects(groupmask, sched_group_cpus(group))) {
  5106. printk(KERN_CONT "\n");
  5107. printk(KERN_ERR "ERROR: repeated CPUs\n");
  5108. break;
  5109. }
  5110. cpumask_or(groupmask, groupmask, sched_group_cpus(group));
  5111. cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group));
  5112. printk(KERN_CONT " %s", str);
  5113. if (group->cpu_power != SCHED_LOAD_SCALE) {
  5114. printk(KERN_CONT " (cpu_power = %d)",
  5115. group->cpu_power);
  5116. }
  5117. group = group->next;
  5118. } while (group != sd->groups);
  5119. printk(KERN_CONT "\n");
  5120. if (!cpumask_equal(sched_domain_span(sd), groupmask))
  5121. printk(KERN_ERR "ERROR: groups don't span domain->span\n");
  5122. if (sd->parent &&
  5123. !cpumask_subset(groupmask, sched_domain_span(sd->parent)))
  5124. printk(KERN_ERR "ERROR: parent span is not a superset "
  5125. "of domain->span\n");
  5126. return 0;
  5127. }
  5128. static void sched_domain_debug(struct sched_domain *sd, int cpu)
  5129. {
  5130. cpumask_var_t groupmask;
  5131. int level = 0;
  5132. if (!sched_domain_debug_enabled)
  5133. return;
  5134. if (!sd) {
  5135. printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
  5136. return;
  5137. }
  5138. printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu);
  5139. if (!alloc_cpumask_var(&groupmask, GFP_KERNEL)) {
  5140. printk(KERN_DEBUG "Cannot load-balance (out of memory)\n");
  5141. return;
  5142. }
  5143. for (;;) {
  5144. if (sched_domain_debug_one(sd, cpu, level, groupmask))
  5145. break;
  5146. level++;
  5147. sd = sd->parent;
  5148. if (!sd)
  5149. break;
  5150. }
  5151. free_cpumask_var(groupmask);
  5152. }
  5153. #else /* !CONFIG_SCHED_DEBUG */
  5154. # define sched_domain_debug(sd, cpu) do { } while (0)
  5155. #endif /* CONFIG_SCHED_DEBUG */
  5156. static int sd_degenerate(struct sched_domain *sd)
  5157. {
  5158. if (cpumask_weight(sched_domain_span(sd)) == 1)
  5159. return 1;
  5160. /* Following flags need at least 2 groups */
  5161. if (sd->flags & (SD_LOAD_BALANCE |
  5162. SD_BALANCE_NEWIDLE |
  5163. SD_BALANCE_FORK |
  5164. SD_BALANCE_EXEC |
  5165. SD_SHARE_CPUPOWER |
  5166. SD_SHARE_PKG_RESOURCES)) {
  5167. if (sd->groups != sd->groups->next)
  5168. return 0;
  5169. }
  5170. /* Following flags don't use groups */
  5171. if (sd->flags & (SD_WAKE_AFFINE))
  5172. return 0;
  5173. return 1;
  5174. }
  5175. static int
  5176. sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
  5177. {
  5178. unsigned long cflags = sd->flags, pflags = parent->flags;
  5179. if (sd_degenerate(parent))
  5180. return 1;
  5181. if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent)))
  5182. return 0;
  5183. /* Flags needing groups don't count if only 1 group in parent */
  5184. if (parent->groups == parent->groups->next) {
  5185. pflags &= ~(SD_LOAD_BALANCE |
  5186. SD_BALANCE_NEWIDLE |
  5187. SD_BALANCE_FORK |
  5188. SD_BALANCE_EXEC |
  5189. SD_SHARE_CPUPOWER |
  5190. SD_SHARE_PKG_RESOURCES);
  5191. if (nr_node_ids == 1)
  5192. pflags &= ~SD_SERIALIZE;
  5193. }
  5194. if (~cflags & pflags)
  5195. return 0;
  5196. return 1;
  5197. }
  5198. static void free_rootdomain(struct root_domain *rd)
  5199. {
  5200. synchronize_sched();
  5201. cpupri_cleanup(&rd->cpupri);
  5202. free_cpumask_var(rd->rto_mask);
  5203. free_cpumask_var(rd->online);
  5204. free_cpumask_var(rd->span);
  5205. kfree(rd);
  5206. }
  5207. static void rq_attach_root(struct rq *rq, struct root_domain *rd)
  5208. {
  5209. struct root_domain *old_rd = NULL;
  5210. unsigned long flags;
  5211. raw_spin_lock_irqsave(&rq->lock, flags);
  5212. if (rq->rd) {
  5213. old_rd = rq->rd;
  5214. if (cpumask_test_cpu(rq->cpu, old_rd->online))
  5215. set_rq_offline(rq);
  5216. cpumask_clear_cpu(rq->cpu, old_rd->span);
  5217. /*
  5218. * If we dont want to free the old_rt yet then
  5219. * set old_rd to NULL to skip the freeing later
  5220. * in this function:
  5221. */
  5222. if (!atomic_dec_and_test(&old_rd->refcount))
  5223. old_rd = NULL;
  5224. }
  5225. atomic_inc(&rd->refcount);
  5226. rq->rd = rd;
  5227. cpumask_set_cpu(rq->cpu, rd->span);
  5228. if (cpumask_test_cpu(rq->cpu, cpu_active_mask))
  5229. set_rq_online(rq);
  5230. raw_spin_unlock_irqrestore(&rq->lock, flags);
  5231. if (old_rd)
  5232. free_rootdomain(old_rd);
  5233. }
  5234. static int init_rootdomain(struct root_domain *rd, bool bootmem)
  5235. {
  5236. gfp_t gfp = GFP_KERNEL;
  5237. memset(rd, 0, sizeof(*rd));
  5238. if (bootmem)
  5239. gfp = GFP_NOWAIT;
  5240. if (!alloc_cpumask_var(&rd->span, gfp))
  5241. goto out;
  5242. if (!alloc_cpumask_var(&rd->online, gfp))
  5243. goto free_span;
  5244. if (!alloc_cpumask_var(&rd->rto_mask, gfp))
  5245. goto free_online;
  5246. if (cpupri_init(&rd->cpupri, bootmem) != 0)
  5247. goto free_rto_mask;
  5248. return 0;
  5249. free_rto_mask:
  5250. free_cpumask_var(rd->rto_mask);
  5251. free_online:
  5252. free_cpumask_var(rd->online);
  5253. free_span:
  5254. free_cpumask_var(rd->span);
  5255. out:
  5256. return -ENOMEM;
  5257. }
  5258. static void init_defrootdomain(void)
  5259. {
  5260. init_rootdomain(&def_root_domain, true);
  5261. atomic_set(&def_root_domain.refcount, 1);
  5262. }
  5263. static struct root_domain *alloc_rootdomain(void)
  5264. {
  5265. struct root_domain *rd;
  5266. rd = kmalloc(sizeof(*rd), GFP_KERNEL);
  5267. if (!rd)
  5268. return NULL;
  5269. if (init_rootdomain(rd, false) != 0) {
  5270. kfree(rd);
  5271. return NULL;
  5272. }
  5273. return rd;
  5274. }
  5275. /*
  5276. * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
  5277. * hold the hotplug lock.
  5278. */
  5279. static void
  5280. cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
  5281. {
  5282. struct rq *rq = cpu_rq(cpu);
  5283. struct sched_domain *tmp;
  5284. /* Remove the sched domains which do not contribute to scheduling. */
  5285. for (tmp = sd; tmp; ) {
  5286. struct sched_domain *parent = tmp->parent;
  5287. if (!parent)
  5288. break;
  5289. if (sd_parent_degenerate(tmp, parent)) {
  5290. tmp->parent = parent->parent;
  5291. if (parent->parent)
  5292. parent->parent->child = tmp;
  5293. } else
  5294. tmp = tmp->parent;
  5295. }
  5296. if (sd && sd_degenerate(sd)) {
  5297. sd = sd->parent;
  5298. if (sd)
  5299. sd->child = NULL;
  5300. }
  5301. sched_domain_debug(sd, cpu);
  5302. rq_attach_root(rq, rd);
  5303. rcu_assign_pointer(rq->sd, sd);
  5304. }
  5305. /* cpus with isolated domains */
  5306. static cpumask_var_t cpu_isolated_map;
  5307. /* Setup the mask of cpus configured for isolated domains */
  5308. static int __init isolated_cpu_setup(char *str)
  5309. {
  5310. alloc_bootmem_cpumask_var(&cpu_isolated_map);
  5311. cpulist_parse(str, cpu_isolated_map);
  5312. return 1;
  5313. }
  5314. __setup("isolcpus=", isolated_cpu_setup);
  5315. /*
  5316. * init_sched_build_groups takes the cpumask we wish to span, and a pointer
  5317. * to a function which identifies what group(along with sched group) a CPU
  5318. * belongs to. The return value of group_fn must be a >= 0 and < nr_cpu_ids
  5319. * (due to the fact that we keep track of groups covered with a struct cpumask).
  5320. *
  5321. * init_sched_build_groups will build a circular linked list of the groups
  5322. * covered by the given span, and will set each group's ->cpumask correctly,
  5323. * and ->cpu_power to 0.
  5324. */
  5325. static void
  5326. init_sched_build_groups(const struct cpumask *span,
  5327. const struct cpumask *cpu_map,
  5328. int (*group_fn)(int cpu, const struct cpumask *cpu_map,
  5329. struct sched_group **sg,
  5330. struct cpumask *tmpmask),
  5331. struct cpumask *covered, struct cpumask *tmpmask)
  5332. {
  5333. struct sched_group *first = NULL, *last = NULL;
  5334. int i;
  5335. cpumask_clear(covered);
  5336. for_each_cpu(i, span) {
  5337. struct sched_group *sg;
  5338. int group = group_fn(i, cpu_map, &sg, tmpmask);
  5339. int j;
  5340. if (cpumask_test_cpu(i, covered))
  5341. continue;
  5342. cpumask_clear(sched_group_cpus(sg));
  5343. sg->cpu_power = 0;
  5344. for_each_cpu(j, span) {
  5345. if (group_fn(j, cpu_map, NULL, tmpmask) != group)
  5346. continue;
  5347. cpumask_set_cpu(j, covered);
  5348. cpumask_set_cpu(j, sched_group_cpus(sg));
  5349. }
  5350. if (!first)
  5351. first = sg;
  5352. if (last)
  5353. last->next = sg;
  5354. last = sg;
  5355. }
  5356. last->next = first;
  5357. }
  5358. #define SD_NODES_PER_DOMAIN 16
  5359. #ifdef CONFIG_NUMA
  5360. /**
  5361. * find_next_best_node - find the next node to include in a sched_domain
  5362. * @node: node whose sched_domain we're building
  5363. * @used_nodes: nodes already in the sched_domain
  5364. *
  5365. * Find the next node to include in a given scheduling domain. Simply
  5366. * finds the closest node not already in the @used_nodes map.
  5367. *
  5368. * Should use nodemask_t.
  5369. */
  5370. static int find_next_best_node(int node, nodemask_t *used_nodes)
  5371. {
  5372. int i, n, val, min_val, best_node = 0;
  5373. min_val = INT_MAX;
  5374. for (i = 0; i < nr_node_ids; i++) {
  5375. /* Start at @node */
  5376. n = (node + i) % nr_node_ids;
  5377. if (!nr_cpus_node(n))
  5378. continue;
  5379. /* Skip already used nodes */
  5380. if (node_isset(n, *used_nodes))
  5381. continue;
  5382. /* Simple min distance search */
  5383. val = node_distance(node, n);
  5384. if (val < min_val) {
  5385. min_val = val;
  5386. best_node = n;
  5387. }
  5388. }
  5389. node_set(best_node, *used_nodes);
  5390. return best_node;
  5391. }
  5392. /**
  5393. * sched_domain_node_span - get a cpumask for a node's sched_domain
  5394. * @node: node whose cpumask we're constructing
  5395. * @span: resulting cpumask
  5396. *
  5397. * Given a node, construct a good cpumask for its sched_domain to span. It
  5398. * should be one that prevents unnecessary balancing, but also spreads tasks
  5399. * out optimally.
  5400. */
  5401. static void sched_domain_node_span(int node, struct cpumask *span)
  5402. {
  5403. nodemask_t used_nodes;
  5404. int i;
  5405. cpumask_clear(span);
  5406. nodes_clear(used_nodes);
  5407. cpumask_or(span, span, cpumask_of_node(node));
  5408. node_set(node, used_nodes);
  5409. for (i = 1; i < SD_NODES_PER_DOMAIN; i++) {
  5410. int next_node = find_next_best_node(node, &used_nodes);
  5411. cpumask_or(span, span, cpumask_of_node(next_node));
  5412. }
  5413. }
  5414. #endif /* CONFIG_NUMA */
  5415. int sched_smt_power_savings = 0, sched_mc_power_savings = 0;
  5416. /*
  5417. * The cpus mask in sched_group and sched_domain hangs off the end.
  5418. *
  5419. * ( See the the comments in include/linux/sched.h:struct sched_group
  5420. * and struct sched_domain. )
  5421. */
  5422. struct static_sched_group {
  5423. struct sched_group sg;
  5424. DECLARE_BITMAP(cpus, CONFIG_NR_CPUS);
  5425. };
  5426. struct static_sched_domain {
  5427. struct sched_domain sd;
  5428. DECLARE_BITMAP(span, CONFIG_NR_CPUS);
  5429. };
  5430. struct s_data {
  5431. #ifdef CONFIG_NUMA
  5432. int sd_allnodes;
  5433. cpumask_var_t domainspan;
  5434. cpumask_var_t covered;
  5435. cpumask_var_t notcovered;
  5436. #endif
  5437. cpumask_var_t nodemask;
  5438. cpumask_var_t this_sibling_map;
  5439. cpumask_var_t this_core_map;
  5440. cpumask_var_t send_covered;
  5441. cpumask_var_t tmpmask;
  5442. struct sched_group **sched_group_nodes;
  5443. struct root_domain *rd;
  5444. };
  5445. enum s_alloc {
  5446. sa_sched_groups = 0,
  5447. sa_rootdomain,
  5448. sa_tmpmask,
  5449. sa_send_covered,
  5450. sa_this_core_map,
  5451. sa_this_sibling_map,
  5452. sa_nodemask,
  5453. sa_sched_group_nodes,
  5454. #ifdef CONFIG_NUMA
  5455. sa_notcovered,
  5456. sa_covered,
  5457. sa_domainspan,
  5458. #endif
  5459. sa_none,
  5460. };
  5461. /*
  5462. * SMT sched-domains:
  5463. */
  5464. #ifdef CONFIG_SCHED_SMT
  5465. static DEFINE_PER_CPU(struct static_sched_domain, cpu_domains);
  5466. static DEFINE_PER_CPU(struct static_sched_group, sched_groups);
  5467. static int
  5468. cpu_to_cpu_group(int cpu, const struct cpumask *cpu_map,
  5469. struct sched_group **sg, struct cpumask *unused)
  5470. {
  5471. if (sg)
  5472. *sg = &per_cpu(sched_groups, cpu).sg;
  5473. return cpu;
  5474. }
  5475. #endif /* CONFIG_SCHED_SMT */
  5476. /*
  5477. * multi-core sched-domains:
  5478. */
  5479. #ifdef CONFIG_SCHED_MC
  5480. static DEFINE_PER_CPU(struct static_sched_domain, core_domains);
  5481. static DEFINE_PER_CPU(struct static_sched_group, sched_group_core);
  5482. #endif /* CONFIG_SCHED_MC */
  5483. #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
  5484. static int
  5485. cpu_to_core_group(int cpu, const struct cpumask *cpu_map,
  5486. struct sched_group **sg, struct cpumask *mask)
  5487. {
  5488. int group;
  5489. cpumask_and(mask, topology_thread_cpumask(cpu), cpu_map);
  5490. group = cpumask_first(mask);
  5491. if (sg)
  5492. *sg = &per_cpu(sched_group_core, group).sg;
  5493. return group;
  5494. }
  5495. #elif defined(CONFIG_SCHED_MC)
  5496. static int
  5497. cpu_to_core_group(int cpu, const struct cpumask *cpu_map,
  5498. struct sched_group **sg, struct cpumask *unused)
  5499. {
  5500. if (sg)
  5501. *sg = &per_cpu(sched_group_core, cpu).sg;
  5502. return cpu;
  5503. }
  5504. #endif
  5505. static DEFINE_PER_CPU(struct static_sched_domain, phys_domains);
  5506. static DEFINE_PER_CPU(struct static_sched_group, sched_group_phys);
  5507. static int
  5508. cpu_to_phys_group(int cpu, const struct cpumask *cpu_map,
  5509. struct sched_group **sg, struct cpumask *mask)
  5510. {
  5511. int group;
  5512. #ifdef CONFIG_SCHED_MC
  5513. cpumask_and(mask, cpu_coregroup_mask(cpu), cpu_map);
  5514. group = cpumask_first(mask);
  5515. #elif defined(CONFIG_SCHED_SMT)
  5516. cpumask_and(mask, topology_thread_cpumask(cpu), cpu_map);
  5517. group = cpumask_first(mask);
  5518. #else
  5519. group = cpu;
  5520. #endif
  5521. if (sg)
  5522. *sg = &per_cpu(sched_group_phys, group).sg;
  5523. return group;
  5524. }
  5525. #ifdef CONFIG_NUMA
  5526. /*
  5527. * The init_sched_build_groups can't handle what we want to do with node
  5528. * groups, so roll our own. Now each node has its own list of groups which
  5529. * gets dynamically allocated.
  5530. */
  5531. static DEFINE_PER_CPU(struct static_sched_domain, node_domains);
  5532. static struct sched_group ***sched_group_nodes_bycpu;
  5533. static DEFINE_PER_CPU(struct static_sched_domain, allnodes_domains);
  5534. static DEFINE_PER_CPU(struct static_sched_group, sched_group_allnodes);
  5535. static int cpu_to_allnodes_group(int cpu, const struct cpumask *cpu_map,
  5536. struct sched_group **sg,
  5537. struct cpumask *nodemask)
  5538. {
  5539. int group;
  5540. cpumask_and(nodemask, cpumask_of_node(cpu_to_node(cpu)), cpu_map);
  5541. group = cpumask_first(nodemask);
  5542. if (sg)
  5543. *sg = &per_cpu(sched_group_allnodes, group).sg;
  5544. return group;
  5545. }
  5546. static void init_numa_sched_groups_power(struct sched_group *group_head)
  5547. {
  5548. struct sched_group *sg = group_head;
  5549. int j;
  5550. if (!sg)
  5551. return;
  5552. do {
  5553. for_each_cpu(j, sched_group_cpus(sg)) {
  5554. struct sched_domain *sd;
  5555. sd = &per_cpu(phys_domains, j).sd;
  5556. if (j != group_first_cpu(sd->groups)) {
  5557. /*
  5558. * Only add "power" once for each
  5559. * physical package.
  5560. */
  5561. continue;
  5562. }
  5563. sg->cpu_power += sd->groups->cpu_power;
  5564. }
  5565. sg = sg->next;
  5566. } while (sg != group_head);
  5567. }
  5568. static int build_numa_sched_groups(struct s_data *d,
  5569. const struct cpumask *cpu_map, int num)
  5570. {
  5571. struct sched_domain *sd;
  5572. struct sched_group *sg, *prev;
  5573. int n, j;
  5574. cpumask_clear(d->covered);
  5575. cpumask_and(d->nodemask, cpumask_of_node(num), cpu_map);
  5576. if (cpumask_empty(d->nodemask)) {
  5577. d->sched_group_nodes[num] = NULL;
  5578. goto out;
  5579. }
  5580. sched_domain_node_span(num, d->domainspan);
  5581. cpumask_and(d->domainspan, d->domainspan, cpu_map);
  5582. sg = kmalloc_node(sizeof(struct sched_group) + cpumask_size(),
  5583. GFP_KERNEL, num);
  5584. if (!sg) {
  5585. printk(KERN_WARNING "Can not alloc domain group for node %d\n",
  5586. num);
  5587. return -ENOMEM;
  5588. }
  5589. d->sched_group_nodes[num] = sg;
  5590. for_each_cpu(j, d->nodemask) {
  5591. sd = &per_cpu(node_domains, j).sd;
  5592. sd->groups = sg;
  5593. }
  5594. sg->cpu_power = 0;
  5595. cpumask_copy(sched_group_cpus(sg), d->nodemask);
  5596. sg->next = sg;
  5597. cpumask_or(d->covered, d->covered, d->nodemask);
  5598. prev = sg;
  5599. for (j = 0; j < nr_node_ids; j++) {
  5600. n = (num + j) % nr_node_ids;
  5601. cpumask_complement(d->notcovered, d->covered);
  5602. cpumask_and(d->tmpmask, d->notcovered, cpu_map);
  5603. cpumask_and(d->tmpmask, d->tmpmask, d->domainspan);
  5604. if (cpumask_empty(d->tmpmask))
  5605. break;
  5606. cpumask_and(d->tmpmask, d->tmpmask, cpumask_of_node(n));
  5607. if (cpumask_empty(d->tmpmask))
  5608. continue;
  5609. sg = kmalloc_node(sizeof(struct sched_group) + cpumask_size(),
  5610. GFP_KERNEL, num);
  5611. if (!sg) {
  5612. printk(KERN_WARNING
  5613. "Can not alloc domain group for node %d\n", j);
  5614. return -ENOMEM;
  5615. }
  5616. sg->cpu_power = 0;
  5617. cpumask_copy(sched_group_cpus(sg), d->tmpmask);
  5618. sg->next = prev->next;
  5619. cpumask_or(d->covered, d->covered, d->tmpmask);
  5620. prev->next = sg;
  5621. prev = sg;
  5622. }
  5623. out:
  5624. return 0;
  5625. }
  5626. #endif /* CONFIG_NUMA */
  5627. #ifdef CONFIG_NUMA
  5628. /* Free memory allocated for various sched_group structures */
  5629. static void free_sched_groups(const struct cpumask *cpu_map,
  5630. struct cpumask *nodemask)
  5631. {
  5632. int cpu, i;
  5633. for_each_cpu(cpu, cpu_map) {
  5634. struct sched_group **sched_group_nodes
  5635. = sched_group_nodes_bycpu[cpu];
  5636. if (!sched_group_nodes)
  5637. continue;
  5638. for (i = 0; i < nr_node_ids; i++) {
  5639. struct sched_group *oldsg, *sg = sched_group_nodes[i];
  5640. cpumask_and(nodemask, cpumask_of_node(i), cpu_map);
  5641. if (cpumask_empty(nodemask))
  5642. continue;
  5643. if (sg == NULL)
  5644. continue;
  5645. sg = sg->next;
  5646. next_sg:
  5647. oldsg = sg;
  5648. sg = sg->next;
  5649. kfree(oldsg);
  5650. if (oldsg != sched_group_nodes[i])
  5651. goto next_sg;
  5652. }
  5653. kfree(sched_group_nodes);
  5654. sched_group_nodes_bycpu[cpu] = NULL;
  5655. }
  5656. }
  5657. #else /* !CONFIG_NUMA */
  5658. static void free_sched_groups(const struct cpumask *cpu_map,
  5659. struct cpumask *nodemask)
  5660. {
  5661. }
  5662. #endif /* CONFIG_NUMA */
  5663. /*
  5664. * Initialize sched groups cpu_power.
  5665. *
  5666. * cpu_power indicates the capacity of sched group, which is used while
  5667. * distributing the load between different sched groups in a sched domain.
  5668. * Typically cpu_power for all the groups in a sched domain will be same unless
  5669. * there are asymmetries in the topology. If there are asymmetries, group
  5670. * having more cpu_power will pickup more load compared to the group having
  5671. * less cpu_power.
  5672. */
  5673. static void init_sched_groups_power(int cpu, struct sched_domain *sd)
  5674. {
  5675. struct sched_domain *child;
  5676. struct sched_group *group;
  5677. long power;
  5678. int weight;
  5679. WARN_ON(!sd || !sd->groups);
  5680. if (cpu != group_first_cpu(sd->groups))
  5681. return;
  5682. child = sd->child;
  5683. sd->groups->cpu_power = 0;
  5684. if (!child) {
  5685. power = SCHED_LOAD_SCALE;
  5686. weight = cpumask_weight(sched_domain_span(sd));
  5687. /*
  5688. * SMT siblings share the power of a single core.
  5689. * Usually multiple threads get a better yield out of
  5690. * that one core than a single thread would have,
  5691. * reflect that in sd->smt_gain.
  5692. */
  5693. if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) {
  5694. power *= sd->smt_gain;
  5695. power /= weight;
  5696. power >>= SCHED_LOAD_SHIFT;
  5697. }
  5698. sd->groups->cpu_power += power;
  5699. return;
  5700. }
  5701. /*
  5702. * Add cpu_power of each child group to this groups cpu_power.
  5703. */
  5704. group = child->groups;
  5705. do {
  5706. sd->groups->cpu_power += group->cpu_power;
  5707. group = group->next;
  5708. } while (group != child->groups);
  5709. }
  5710. /*
  5711. * Initializers for schedule domains
  5712. * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
  5713. */
  5714. #ifdef CONFIG_SCHED_DEBUG
  5715. # define SD_INIT_NAME(sd, type) sd->name = #type
  5716. #else
  5717. # define SD_INIT_NAME(sd, type) do { } while (0)
  5718. #endif
  5719. #define SD_INIT(sd, type) sd_init_##type(sd)
  5720. #define SD_INIT_FUNC(type) \
  5721. static noinline void sd_init_##type(struct sched_domain *sd) \
  5722. { \
  5723. memset(sd, 0, sizeof(*sd)); \
  5724. *sd = SD_##type##_INIT; \
  5725. sd->level = SD_LV_##type; \
  5726. SD_INIT_NAME(sd, type); \
  5727. }
  5728. SD_INIT_FUNC(CPU)
  5729. #ifdef CONFIG_NUMA
  5730. SD_INIT_FUNC(ALLNODES)
  5731. SD_INIT_FUNC(NODE)
  5732. #endif
  5733. #ifdef CONFIG_SCHED_SMT
  5734. SD_INIT_FUNC(SIBLING)
  5735. #endif
  5736. #ifdef CONFIG_SCHED_MC
  5737. SD_INIT_FUNC(MC)
  5738. #endif
  5739. static int default_relax_domain_level = -1;
  5740. static int __init setup_relax_domain_level(char *str)
  5741. {
  5742. unsigned long val;
  5743. val = simple_strtoul(str, NULL, 0);
  5744. if (val < SD_LV_MAX)
  5745. default_relax_domain_level = val;
  5746. return 1;
  5747. }
  5748. __setup("relax_domain_level=", setup_relax_domain_level);
  5749. static void set_domain_attribute(struct sched_domain *sd,
  5750. struct sched_domain_attr *attr)
  5751. {
  5752. int request;
  5753. if (!attr || attr->relax_domain_level < 0) {
  5754. if (default_relax_domain_level < 0)
  5755. return;
  5756. else
  5757. request = default_relax_domain_level;
  5758. } else
  5759. request = attr->relax_domain_level;
  5760. if (request < sd->level) {
  5761. /* turn off idle balance on this domain */
  5762. sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
  5763. } else {
  5764. /* turn on idle balance on this domain */
  5765. sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
  5766. }
  5767. }
  5768. static void __free_domain_allocs(struct s_data *d, enum s_alloc what,
  5769. const struct cpumask *cpu_map)
  5770. {
  5771. switch (what) {
  5772. case sa_sched_groups:
  5773. free_sched_groups(cpu_map, d->tmpmask); /* fall through */
  5774. d->sched_group_nodes = NULL;
  5775. case sa_rootdomain:
  5776. free_rootdomain(d->rd); /* fall through */
  5777. case sa_tmpmask:
  5778. free_cpumask_var(d->tmpmask); /* fall through */
  5779. case sa_send_covered:
  5780. free_cpumask_var(d->send_covered); /* fall through */
  5781. case sa_this_core_map:
  5782. free_cpumask_var(d->this_core_map); /* fall through */
  5783. case sa_this_sibling_map:
  5784. free_cpumask_var(d->this_sibling_map); /* fall through */
  5785. case sa_nodemask:
  5786. free_cpumask_var(d->nodemask); /* fall through */
  5787. case sa_sched_group_nodes:
  5788. #ifdef CONFIG_NUMA
  5789. kfree(d->sched_group_nodes); /* fall through */
  5790. case sa_notcovered:
  5791. free_cpumask_var(d->notcovered); /* fall through */
  5792. case sa_covered:
  5793. free_cpumask_var(d->covered); /* fall through */
  5794. case sa_domainspan:
  5795. free_cpumask_var(d->domainspan); /* fall through */
  5796. #endif
  5797. case sa_none:
  5798. break;
  5799. }
  5800. }
  5801. static enum s_alloc __visit_domain_allocation_hell(struct s_data *d,
  5802. const struct cpumask *cpu_map)
  5803. {
  5804. #ifdef CONFIG_NUMA
  5805. if (!alloc_cpumask_var(&d->domainspan, GFP_KERNEL))
  5806. return sa_none;
  5807. if (!alloc_cpumask_var(&d->covered, GFP_KERNEL))
  5808. return sa_domainspan;
  5809. if (!alloc_cpumask_var(&d->notcovered, GFP_KERNEL))
  5810. return sa_covered;
  5811. /* Allocate the per-node list of sched groups */
  5812. d->sched_group_nodes = kcalloc(nr_node_ids,
  5813. sizeof(struct sched_group *), GFP_KERNEL);
  5814. if (!d->sched_group_nodes) {
  5815. printk(KERN_WARNING "Can not alloc sched group node list\n");
  5816. return sa_notcovered;
  5817. }
  5818. sched_group_nodes_bycpu[cpumask_first(cpu_map)] = d->sched_group_nodes;
  5819. #endif
  5820. if (!alloc_cpumask_var(&d->nodemask, GFP_KERNEL))
  5821. return sa_sched_group_nodes;
  5822. if (!alloc_cpumask_var(&d->this_sibling_map, GFP_KERNEL))
  5823. return sa_nodemask;
  5824. if (!alloc_cpumask_var(&d->this_core_map, GFP_KERNEL))
  5825. return sa_this_sibling_map;
  5826. if (!alloc_cpumask_var(&d->send_covered, GFP_KERNEL))
  5827. return sa_this_core_map;
  5828. if (!alloc_cpumask_var(&d->tmpmask, GFP_KERNEL))
  5829. return sa_send_covered;
  5830. d->rd = alloc_rootdomain();
  5831. if (!d->rd) {
  5832. printk(KERN_WARNING "Cannot alloc root domain\n");
  5833. return sa_tmpmask;
  5834. }
  5835. return sa_rootdomain;
  5836. }
  5837. static struct sched_domain *__build_numa_sched_domains(struct s_data *d,
  5838. const struct cpumask *cpu_map, struct sched_domain_attr *attr, int i)
  5839. {
  5840. struct sched_domain *sd = NULL;
  5841. #ifdef CONFIG_NUMA
  5842. struct sched_domain *parent;
  5843. d->sd_allnodes = 0;
  5844. if (cpumask_weight(cpu_map) >
  5845. SD_NODES_PER_DOMAIN * cpumask_weight(d->nodemask)) {
  5846. sd = &per_cpu(allnodes_domains, i).sd;
  5847. SD_INIT(sd, ALLNODES);
  5848. set_domain_attribute(sd, attr);
  5849. cpumask_copy(sched_domain_span(sd), cpu_map);
  5850. cpu_to_allnodes_group(i, cpu_map, &sd->groups, d->tmpmask);
  5851. d->sd_allnodes = 1;
  5852. }
  5853. parent = sd;
  5854. sd = &per_cpu(node_domains, i).sd;
  5855. SD_INIT(sd, NODE);
  5856. set_domain_attribute(sd, attr);
  5857. sched_domain_node_span(cpu_to_node(i), sched_domain_span(sd));
  5858. sd->parent = parent;
  5859. if (parent)
  5860. parent->child = sd;
  5861. cpumask_and(sched_domain_span(sd), sched_domain_span(sd), cpu_map);
  5862. #endif
  5863. return sd;
  5864. }
  5865. static struct sched_domain *__build_cpu_sched_domain(struct s_data *d,
  5866. const struct cpumask *cpu_map, struct sched_domain_attr *attr,
  5867. struct sched_domain *parent, int i)
  5868. {
  5869. struct sched_domain *sd;
  5870. sd = &per_cpu(phys_domains, i).sd;
  5871. SD_INIT(sd, CPU);
  5872. set_domain_attribute(sd, attr);
  5873. cpumask_copy(sched_domain_span(sd), d->nodemask);
  5874. sd->parent = parent;
  5875. if (parent)
  5876. parent->child = sd;
  5877. cpu_to_phys_group(i, cpu_map, &sd->groups, d->tmpmask);
  5878. return sd;
  5879. }
  5880. static struct sched_domain *__build_mc_sched_domain(struct s_data *d,
  5881. const struct cpumask *cpu_map, struct sched_domain_attr *attr,
  5882. struct sched_domain *parent, int i)
  5883. {
  5884. struct sched_domain *sd = parent;
  5885. #ifdef CONFIG_SCHED_MC
  5886. sd = &per_cpu(core_domains, i).sd;
  5887. SD_INIT(sd, MC);
  5888. set_domain_attribute(sd, attr);
  5889. cpumask_and(sched_domain_span(sd), cpu_map, cpu_coregroup_mask(i));
  5890. sd->parent = parent;
  5891. parent->child = sd;
  5892. cpu_to_core_group(i, cpu_map, &sd->groups, d->tmpmask);
  5893. #endif
  5894. return sd;
  5895. }
  5896. static struct sched_domain *__build_smt_sched_domain(struct s_data *d,
  5897. const struct cpumask *cpu_map, struct sched_domain_attr *attr,
  5898. struct sched_domain *parent, int i)
  5899. {
  5900. struct sched_domain *sd = parent;
  5901. #ifdef CONFIG_SCHED_SMT
  5902. sd = &per_cpu(cpu_domains, i).sd;
  5903. SD_INIT(sd, SIBLING);
  5904. set_domain_attribute(sd, attr);
  5905. cpumask_and(sched_domain_span(sd), cpu_map, topology_thread_cpumask(i));
  5906. sd->parent = parent;
  5907. parent->child = sd;
  5908. cpu_to_cpu_group(i, cpu_map, &sd->groups, d->tmpmask);
  5909. #endif
  5910. return sd;
  5911. }
  5912. static void build_sched_groups(struct s_data *d, enum sched_domain_level l,
  5913. const struct cpumask *cpu_map, int cpu)
  5914. {
  5915. switch (l) {
  5916. #ifdef CONFIG_SCHED_SMT
  5917. case SD_LV_SIBLING: /* set up CPU (sibling) groups */
  5918. cpumask_and(d->this_sibling_map, cpu_map,
  5919. topology_thread_cpumask(cpu));
  5920. if (cpu == cpumask_first(d->this_sibling_map))
  5921. init_sched_build_groups(d->this_sibling_map, cpu_map,
  5922. &cpu_to_cpu_group,
  5923. d->send_covered, d->tmpmask);
  5924. break;
  5925. #endif
  5926. #ifdef CONFIG_SCHED_MC
  5927. case SD_LV_MC: /* set up multi-core groups */
  5928. cpumask_and(d->this_core_map, cpu_map, cpu_coregroup_mask(cpu));
  5929. if (cpu == cpumask_first(d->this_core_map))
  5930. init_sched_build_groups(d->this_core_map, cpu_map,
  5931. &cpu_to_core_group,
  5932. d->send_covered, d->tmpmask);
  5933. break;
  5934. #endif
  5935. case SD_LV_CPU: /* set up physical groups */
  5936. cpumask_and(d->nodemask, cpumask_of_node(cpu), cpu_map);
  5937. if (!cpumask_empty(d->nodemask))
  5938. init_sched_build_groups(d->nodemask, cpu_map,
  5939. &cpu_to_phys_group,
  5940. d->send_covered, d->tmpmask);
  5941. break;
  5942. #ifdef CONFIG_NUMA
  5943. case SD_LV_ALLNODES:
  5944. init_sched_build_groups(cpu_map, cpu_map, &cpu_to_allnodes_group,
  5945. d->send_covered, d->tmpmask);
  5946. break;
  5947. #endif
  5948. default:
  5949. break;
  5950. }
  5951. }
  5952. /*
  5953. * Build sched domains for a given set of cpus and attach the sched domains
  5954. * to the individual cpus
  5955. */
  5956. static int __build_sched_domains(const struct cpumask *cpu_map,
  5957. struct sched_domain_attr *attr)
  5958. {
  5959. enum s_alloc alloc_state = sa_none;
  5960. struct s_data d;
  5961. struct sched_domain *sd;
  5962. int i;
  5963. #ifdef CONFIG_NUMA
  5964. d.sd_allnodes = 0;
  5965. #endif
  5966. alloc_state = __visit_domain_allocation_hell(&d, cpu_map);
  5967. if (alloc_state != sa_rootdomain)
  5968. goto error;
  5969. alloc_state = sa_sched_groups;
  5970. /*
  5971. * Set up domains for cpus specified by the cpu_map.
  5972. */
  5973. for_each_cpu(i, cpu_map) {
  5974. cpumask_and(d.nodemask, cpumask_of_node(cpu_to_node(i)),
  5975. cpu_map);
  5976. sd = __build_numa_sched_domains(&d, cpu_map, attr, i);
  5977. sd = __build_cpu_sched_domain(&d, cpu_map, attr, sd, i);
  5978. sd = __build_mc_sched_domain(&d, cpu_map, attr, sd, i);
  5979. sd = __build_smt_sched_domain(&d, cpu_map, attr, sd, i);
  5980. }
  5981. for_each_cpu(i, cpu_map) {
  5982. build_sched_groups(&d, SD_LV_SIBLING, cpu_map, i);
  5983. build_sched_groups(&d, SD_LV_MC, cpu_map, i);
  5984. }
  5985. /* Set up physical groups */
  5986. for (i = 0; i < nr_node_ids; i++)
  5987. build_sched_groups(&d, SD_LV_CPU, cpu_map, i);
  5988. #ifdef CONFIG_NUMA
  5989. /* Set up node groups */
  5990. if (d.sd_allnodes)
  5991. build_sched_groups(&d, SD_LV_ALLNODES, cpu_map, 0);
  5992. for (i = 0; i < nr_node_ids; i++)
  5993. if (build_numa_sched_groups(&d, cpu_map, i))
  5994. goto error;
  5995. #endif
  5996. /* Calculate CPU power for physical packages and nodes */
  5997. #ifdef CONFIG_SCHED_SMT
  5998. for_each_cpu(i, cpu_map) {
  5999. sd = &per_cpu(cpu_domains, i).sd;
  6000. init_sched_groups_power(i, sd);
  6001. }
  6002. #endif
  6003. #ifdef CONFIG_SCHED_MC
  6004. for_each_cpu(i, cpu_map) {
  6005. sd = &per_cpu(core_domains, i).sd;
  6006. init_sched_groups_power(i, sd);
  6007. }
  6008. #endif
  6009. for_each_cpu(i, cpu_map) {
  6010. sd = &per_cpu(phys_domains, i).sd;
  6011. init_sched_groups_power(i, sd);
  6012. }
  6013. #ifdef CONFIG_NUMA
  6014. for (i = 0; i < nr_node_ids; i++)
  6015. init_numa_sched_groups_power(d.sched_group_nodes[i]);
  6016. if (d.sd_allnodes) {
  6017. struct sched_group *sg;
  6018. cpu_to_allnodes_group(cpumask_first(cpu_map), cpu_map, &sg,
  6019. d.tmpmask);
  6020. init_numa_sched_groups_power(sg);
  6021. }
  6022. #endif
  6023. /* Attach the domains */
  6024. for_each_cpu(i, cpu_map) {
  6025. #ifdef CONFIG_SCHED_SMT
  6026. sd = &per_cpu(cpu_domains, i).sd;
  6027. #elif defined(CONFIG_SCHED_MC)
  6028. sd = &per_cpu(core_domains, i).sd;
  6029. #else
  6030. sd = &per_cpu(phys_domains, i).sd;
  6031. #endif
  6032. cpu_attach_domain(sd, d.rd, i);
  6033. }
  6034. d.sched_group_nodes = NULL; /* don't free this we still need it */
  6035. __free_domain_allocs(&d, sa_tmpmask, cpu_map);
  6036. return 0;
  6037. error:
  6038. __free_domain_allocs(&d, alloc_state, cpu_map);
  6039. return -ENOMEM;
  6040. }
  6041. static int build_sched_domains(const struct cpumask *cpu_map)
  6042. {
  6043. return __build_sched_domains(cpu_map, NULL);
  6044. }
  6045. static cpumask_var_t *doms_cur; /* current sched domains */
  6046. static int ndoms_cur; /* number of sched domains in 'doms_cur' */
  6047. static struct sched_domain_attr *dattr_cur;
  6048. /* attribues of custom domains in 'doms_cur' */
  6049. /*
  6050. * Special case: If a kmalloc of a doms_cur partition (array of
  6051. * cpumask) fails, then fallback to a single sched domain,
  6052. * as determined by the single cpumask fallback_doms.
  6053. */
  6054. static cpumask_var_t fallback_doms;
  6055. /*
  6056. * arch_update_cpu_topology lets virtualized architectures update the
  6057. * cpu core maps. It is supposed to return 1 if the topology changed
  6058. * or 0 if it stayed the same.
  6059. */
  6060. int __attribute__((weak)) arch_update_cpu_topology(void)
  6061. {
  6062. return 0;
  6063. }
  6064. cpumask_var_t *alloc_sched_domains(unsigned int ndoms)
  6065. {
  6066. int i;
  6067. cpumask_var_t *doms;
  6068. doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL);
  6069. if (!doms)
  6070. return NULL;
  6071. for (i = 0; i < ndoms; i++) {
  6072. if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) {
  6073. free_sched_domains(doms, i);
  6074. return NULL;
  6075. }
  6076. }
  6077. return doms;
  6078. }
  6079. void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms)
  6080. {
  6081. unsigned int i;
  6082. for (i = 0; i < ndoms; i++)
  6083. free_cpumask_var(doms[i]);
  6084. kfree(doms);
  6085. }
  6086. /*
  6087. * Set up scheduler domains and groups. Callers must hold the hotplug lock.
  6088. * For now this just excludes isolated cpus, but could be used to
  6089. * exclude other special cases in the future.
  6090. */
  6091. static int arch_init_sched_domains(const struct cpumask *cpu_map)
  6092. {
  6093. int err;
  6094. arch_update_cpu_topology();
  6095. ndoms_cur = 1;
  6096. doms_cur = alloc_sched_domains(ndoms_cur);
  6097. if (!doms_cur)
  6098. doms_cur = &fallback_doms;
  6099. cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map);
  6100. dattr_cur = NULL;
  6101. err = build_sched_domains(doms_cur[0]);
  6102. register_sched_domain_sysctl();
  6103. return err;
  6104. }
  6105. static void arch_destroy_sched_domains(const struct cpumask *cpu_map,
  6106. struct cpumask *tmpmask)
  6107. {
  6108. free_sched_groups(cpu_map, tmpmask);
  6109. }
  6110. /*
  6111. * Detach sched domains from a group of cpus specified in cpu_map
  6112. * These cpus will now be attached to the NULL domain
  6113. */
  6114. static void detach_destroy_domains(const struct cpumask *cpu_map)
  6115. {
  6116. /* Save because hotplug lock held. */
  6117. static DECLARE_BITMAP(tmpmask, CONFIG_NR_CPUS);
  6118. int i;
  6119. for_each_cpu(i, cpu_map)
  6120. cpu_attach_domain(NULL, &def_root_domain, i);
  6121. synchronize_sched();
  6122. arch_destroy_sched_domains(cpu_map, to_cpumask(tmpmask));
  6123. }
  6124. /* handle null as "default" */
  6125. static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
  6126. struct sched_domain_attr *new, int idx_new)
  6127. {
  6128. struct sched_domain_attr tmp;
  6129. /* fast path */
  6130. if (!new && !cur)
  6131. return 1;
  6132. tmp = SD_ATTR_INIT;
  6133. return !memcmp(cur ? (cur + idx_cur) : &tmp,
  6134. new ? (new + idx_new) : &tmp,
  6135. sizeof(struct sched_domain_attr));
  6136. }
  6137. /*
  6138. * Partition sched domains as specified by the 'ndoms_new'
  6139. * cpumasks in the array doms_new[] of cpumasks. This compares
  6140. * doms_new[] to the current sched domain partitioning, doms_cur[].
  6141. * It destroys each deleted domain and builds each new domain.
  6142. *
  6143. * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
  6144. * The masks don't intersect (don't overlap.) We should setup one
  6145. * sched domain for each mask. CPUs not in any of the cpumasks will
  6146. * not be load balanced. If the same cpumask appears both in the
  6147. * current 'doms_cur' domains and in the new 'doms_new', we can leave
  6148. * it as it is.
  6149. *
  6150. * The passed in 'doms_new' should be allocated using
  6151. * alloc_sched_domains. This routine takes ownership of it and will
  6152. * free_sched_domains it when done with it. If the caller failed the
  6153. * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
  6154. * and partition_sched_domains() will fallback to the single partition
  6155. * 'fallback_doms', it also forces the domains to be rebuilt.
  6156. *
  6157. * If doms_new == NULL it will be replaced with cpu_online_mask.
  6158. * ndoms_new == 0 is a special case for destroying existing domains,
  6159. * and it will not create the default domain.
  6160. *
  6161. * Call with hotplug lock held
  6162. */
  6163. void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
  6164. struct sched_domain_attr *dattr_new)
  6165. {
  6166. int i, j, n;
  6167. int new_topology;
  6168. mutex_lock(&sched_domains_mutex);
  6169. /* always unregister in case we don't destroy any domains */
  6170. unregister_sched_domain_sysctl();
  6171. /* Let architecture update cpu core mappings. */
  6172. new_topology = arch_update_cpu_topology();
  6173. n = doms_new ? ndoms_new : 0;
  6174. /* Destroy deleted domains */
  6175. for (i = 0; i < ndoms_cur; i++) {
  6176. for (j = 0; j < n && !new_topology; j++) {
  6177. if (cpumask_equal(doms_cur[i], doms_new[j])
  6178. && dattrs_equal(dattr_cur, i, dattr_new, j))
  6179. goto match1;
  6180. }
  6181. /* no match - a current sched domain not in new doms_new[] */
  6182. detach_destroy_domains(doms_cur[i]);
  6183. match1:
  6184. ;
  6185. }
  6186. if (doms_new == NULL) {
  6187. ndoms_cur = 0;
  6188. doms_new = &fallback_doms;
  6189. cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map);
  6190. WARN_ON_ONCE(dattr_new);
  6191. }
  6192. /* Build new domains */
  6193. for (i = 0; i < ndoms_new; i++) {
  6194. for (j = 0; j < ndoms_cur && !new_topology; j++) {
  6195. if (cpumask_equal(doms_new[i], doms_cur[j])
  6196. && dattrs_equal(dattr_new, i, dattr_cur, j))
  6197. goto match2;
  6198. }
  6199. /* no match - add a new doms_new */
  6200. __build_sched_domains(doms_new[i],
  6201. dattr_new ? dattr_new + i : NULL);
  6202. match2:
  6203. ;
  6204. }
  6205. /* Remember the new sched domains */
  6206. if (doms_cur != &fallback_doms)
  6207. free_sched_domains(doms_cur, ndoms_cur);
  6208. kfree(dattr_cur); /* kfree(NULL) is safe */
  6209. doms_cur = doms_new;
  6210. dattr_cur = dattr_new;
  6211. ndoms_cur = ndoms_new;
  6212. register_sched_domain_sysctl();
  6213. mutex_unlock(&sched_domains_mutex);
  6214. }
  6215. #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
  6216. static void arch_reinit_sched_domains(void)
  6217. {
  6218. get_online_cpus();
  6219. /* Destroy domains first to force the rebuild */
  6220. partition_sched_domains(0, NULL, NULL);
  6221. rebuild_sched_domains();
  6222. put_online_cpus();
  6223. }
  6224. static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt)
  6225. {
  6226. unsigned int level = 0;
  6227. if (sscanf(buf, "%u", &level) != 1)
  6228. return -EINVAL;
  6229. /*
  6230. * level is always be positive so don't check for
  6231. * level < POWERSAVINGS_BALANCE_NONE which is 0
  6232. * What happens on 0 or 1 byte write,
  6233. * need to check for count as well?
  6234. */
  6235. if (level >= MAX_POWERSAVINGS_BALANCE_LEVELS)
  6236. return -EINVAL;
  6237. if (smt)
  6238. sched_smt_power_savings = level;
  6239. else
  6240. sched_mc_power_savings = level;
  6241. arch_reinit_sched_domains();
  6242. return count;
  6243. }
  6244. #ifdef CONFIG_SCHED_MC
  6245. static ssize_t sched_mc_power_savings_show(struct sysdev_class *class,
  6246. char *page)
  6247. {
  6248. return sprintf(page, "%u\n", sched_mc_power_savings);
  6249. }
  6250. static ssize_t sched_mc_power_savings_store(struct sysdev_class *class,
  6251. const char *buf, size_t count)
  6252. {
  6253. return sched_power_savings_store(buf, count, 0);
  6254. }
  6255. static SYSDEV_CLASS_ATTR(sched_mc_power_savings, 0644,
  6256. sched_mc_power_savings_show,
  6257. sched_mc_power_savings_store);
  6258. #endif
  6259. #ifdef CONFIG_SCHED_SMT
  6260. static ssize_t sched_smt_power_savings_show(struct sysdev_class *dev,
  6261. char *page)
  6262. {
  6263. return sprintf(page, "%u\n", sched_smt_power_savings);
  6264. }
  6265. static ssize_t sched_smt_power_savings_store(struct sysdev_class *dev,
  6266. const char *buf, size_t count)
  6267. {
  6268. return sched_power_savings_store(buf, count, 1);
  6269. }
  6270. static SYSDEV_CLASS_ATTR(sched_smt_power_savings, 0644,
  6271. sched_smt_power_savings_show,
  6272. sched_smt_power_savings_store);
  6273. #endif
  6274. int __init sched_create_sysfs_power_savings_entries(struct sysdev_class *cls)
  6275. {
  6276. int err = 0;
  6277. #ifdef CONFIG_SCHED_SMT
  6278. if (smt_capable())
  6279. err = sysfs_create_file(&cls->kset.kobj,
  6280. &attr_sched_smt_power_savings.attr);
  6281. #endif
  6282. #ifdef CONFIG_SCHED_MC
  6283. if (!err && mc_capable())
  6284. err = sysfs_create_file(&cls->kset.kobj,
  6285. &attr_sched_mc_power_savings.attr);
  6286. #endif
  6287. return err;
  6288. }
  6289. #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
  6290. #ifndef CONFIG_CPUSETS
  6291. /*
  6292. * Add online and remove offline CPUs from the scheduler domains.
  6293. * When cpusets are enabled they take over this function.
  6294. */
  6295. static int update_sched_domains(struct notifier_block *nfb,
  6296. unsigned long action, void *hcpu)
  6297. {
  6298. switch (action) {
  6299. case CPU_ONLINE:
  6300. case CPU_ONLINE_FROZEN:
  6301. case CPU_DOWN_PREPARE:
  6302. case CPU_DOWN_PREPARE_FROZEN:
  6303. case CPU_DOWN_FAILED:
  6304. case CPU_DOWN_FAILED_FROZEN:
  6305. partition_sched_domains(1, NULL, NULL);
  6306. return NOTIFY_OK;
  6307. default:
  6308. return NOTIFY_DONE;
  6309. }
  6310. }
  6311. #endif
  6312. static int update_runtime(struct notifier_block *nfb,
  6313. unsigned long action, void *hcpu)
  6314. {
  6315. int cpu = (int)(long)hcpu;
  6316. switch (action) {
  6317. case CPU_DOWN_PREPARE:
  6318. case CPU_DOWN_PREPARE_FROZEN:
  6319. disable_runtime(cpu_rq(cpu));
  6320. return NOTIFY_OK;
  6321. case CPU_DOWN_FAILED:
  6322. case CPU_DOWN_FAILED_FROZEN:
  6323. case CPU_ONLINE:
  6324. case CPU_ONLINE_FROZEN:
  6325. enable_runtime(cpu_rq(cpu));
  6326. return NOTIFY_OK;
  6327. default:
  6328. return NOTIFY_DONE;
  6329. }
  6330. }
  6331. void __init sched_init_smp(void)
  6332. {
  6333. cpumask_var_t non_isolated_cpus;
  6334. alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL);
  6335. alloc_cpumask_var(&fallback_doms, GFP_KERNEL);
  6336. #if defined(CONFIG_NUMA)
  6337. sched_group_nodes_bycpu = kzalloc(nr_cpu_ids * sizeof(void **),
  6338. GFP_KERNEL);
  6339. BUG_ON(sched_group_nodes_bycpu == NULL);
  6340. #endif
  6341. get_online_cpus();
  6342. mutex_lock(&sched_domains_mutex);
  6343. arch_init_sched_domains(cpu_active_mask);
  6344. cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map);
  6345. if (cpumask_empty(non_isolated_cpus))
  6346. cpumask_set_cpu(smp_processor_id(), non_isolated_cpus);
  6347. mutex_unlock(&sched_domains_mutex);
  6348. put_online_cpus();
  6349. #ifndef CONFIG_CPUSETS
  6350. /* XXX: Theoretical race here - CPU may be hotplugged now */
  6351. hotcpu_notifier(update_sched_domains, 0);
  6352. #endif
  6353. /* RT runtime code needs to handle some hotplug events */
  6354. hotcpu_notifier(update_runtime, 0);
  6355. init_hrtick();
  6356. /* Move init over to a non-isolated CPU */
  6357. if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0)
  6358. BUG();
  6359. sched_init_granularity();
  6360. free_cpumask_var(non_isolated_cpus);
  6361. init_sched_rt_class();
  6362. }
  6363. #else
  6364. void __init sched_init_smp(void)
  6365. {
  6366. sched_init_granularity();
  6367. }
  6368. #endif /* CONFIG_SMP */
  6369. const_debug unsigned int sysctl_timer_migration = 1;
  6370. int in_sched_functions(unsigned long addr)
  6371. {
  6372. return in_lock_functions(addr) ||
  6373. (addr >= (unsigned long)__sched_text_start
  6374. && addr < (unsigned long)__sched_text_end);
  6375. }
  6376. static void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq)
  6377. {
  6378. cfs_rq->tasks_timeline = RB_ROOT;
  6379. INIT_LIST_HEAD(&cfs_rq->tasks);
  6380. #ifdef CONFIG_FAIR_GROUP_SCHED
  6381. cfs_rq->rq = rq;
  6382. #endif
  6383. cfs_rq->min_vruntime = (u64)(-(1LL << 20));
  6384. }
  6385. static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
  6386. {
  6387. struct rt_prio_array *array;
  6388. int i;
  6389. array = &rt_rq->active;
  6390. for (i = 0; i < MAX_RT_PRIO; i++) {
  6391. INIT_LIST_HEAD(array->queue + i);
  6392. __clear_bit(i, array->bitmap);
  6393. }
  6394. /* delimiter for bitsearch: */
  6395. __set_bit(MAX_RT_PRIO, array->bitmap);
  6396. #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
  6397. rt_rq->highest_prio.curr = MAX_RT_PRIO;
  6398. #ifdef CONFIG_SMP
  6399. rt_rq->highest_prio.next = MAX_RT_PRIO;
  6400. #endif
  6401. #endif
  6402. #ifdef CONFIG_SMP
  6403. rt_rq->rt_nr_migratory = 0;
  6404. rt_rq->overloaded = 0;
  6405. plist_head_init_raw(&rt_rq->pushable_tasks, &rq->lock);
  6406. #endif
  6407. rt_rq->rt_time = 0;
  6408. rt_rq->rt_throttled = 0;
  6409. rt_rq->rt_runtime = 0;
  6410. raw_spin_lock_init(&rt_rq->rt_runtime_lock);
  6411. #ifdef CONFIG_RT_GROUP_SCHED
  6412. rt_rq->rt_nr_boosted = 0;
  6413. rt_rq->rq = rq;
  6414. #endif
  6415. }
  6416. #ifdef CONFIG_FAIR_GROUP_SCHED
  6417. static void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
  6418. struct sched_entity *se, int cpu, int add,
  6419. struct sched_entity *parent)
  6420. {
  6421. struct rq *rq = cpu_rq(cpu);
  6422. tg->cfs_rq[cpu] = cfs_rq;
  6423. init_cfs_rq(cfs_rq, rq);
  6424. cfs_rq->tg = tg;
  6425. if (add)
  6426. list_add(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list);
  6427. tg->se[cpu] = se;
  6428. /* se could be NULL for init_task_group */
  6429. if (!se)
  6430. return;
  6431. if (!parent)
  6432. se->cfs_rq = &rq->cfs;
  6433. else
  6434. se->cfs_rq = parent->my_q;
  6435. se->my_q = cfs_rq;
  6436. se->load.weight = tg->shares;
  6437. se->load.inv_weight = 0;
  6438. se->parent = parent;
  6439. }
  6440. #endif
  6441. #ifdef CONFIG_RT_GROUP_SCHED
  6442. static void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
  6443. struct sched_rt_entity *rt_se, int cpu, int add,
  6444. struct sched_rt_entity *parent)
  6445. {
  6446. struct rq *rq = cpu_rq(cpu);
  6447. tg->rt_rq[cpu] = rt_rq;
  6448. init_rt_rq(rt_rq, rq);
  6449. rt_rq->tg = tg;
  6450. rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime;
  6451. if (add)
  6452. list_add(&rt_rq->leaf_rt_rq_list, &rq->leaf_rt_rq_list);
  6453. tg->rt_se[cpu] = rt_se;
  6454. if (!rt_se)
  6455. return;
  6456. if (!parent)
  6457. rt_se->rt_rq = &rq->rt;
  6458. else
  6459. rt_se->rt_rq = parent->my_q;
  6460. rt_se->my_q = rt_rq;
  6461. rt_se->parent = parent;
  6462. INIT_LIST_HEAD(&rt_se->run_list);
  6463. }
  6464. #endif
  6465. void __init sched_init(void)
  6466. {
  6467. int i, j;
  6468. unsigned long alloc_size = 0, ptr;
  6469. #ifdef CONFIG_FAIR_GROUP_SCHED
  6470. alloc_size += 2 * nr_cpu_ids * sizeof(void **);
  6471. #endif
  6472. #ifdef CONFIG_RT_GROUP_SCHED
  6473. alloc_size += 2 * nr_cpu_ids * sizeof(void **);
  6474. #endif
  6475. #ifdef CONFIG_CPUMASK_OFFSTACK
  6476. alloc_size += num_possible_cpus() * cpumask_size();
  6477. #endif
  6478. if (alloc_size) {
  6479. ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT);
  6480. #ifdef CONFIG_FAIR_GROUP_SCHED
  6481. init_task_group.se = (struct sched_entity **)ptr;
  6482. ptr += nr_cpu_ids * sizeof(void **);
  6483. init_task_group.cfs_rq = (struct cfs_rq **)ptr;
  6484. ptr += nr_cpu_ids * sizeof(void **);
  6485. #endif /* CONFIG_FAIR_GROUP_SCHED */
  6486. #ifdef CONFIG_RT_GROUP_SCHED
  6487. init_task_group.rt_se = (struct sched_rt_entity **)ptr;
  6488. ptr += nr_cpu_ids * sizeof(void **);
  6489. init_task_group.rt_rq = (struct rt_rq **)ptr;
  6490. ptr += nr_cpu_ids * sizeof(void **);
  6491. #endif /* CONFIG_RT_GROUP_SCHED */
  6492. #ifdef CONFIG_CPUMASK_OFFSTACK
  6493. for_each_possible_cpu(i) {
  6494. per_cpu(load_balance_tmpmask, i) = (void *)ptr;
  6495. ptr += cpumask_size();
  6496. }
  6497. #endif /* CONFIG_CPUMASK_OFFSTACK */
  6498. }
  6499. #ifdef CONFIG_SMP
  6500. init_defrootdomain();
  6501. #endif
  6502. init_rt_bandwidth(&def_rt_bandwidth,
  6503. global_rt_period(), global_rt_runtime());
  6504. #ifdef CONFIG_RT_GROUP_SCHED
  6505. init_rt_bandwidth(&init_task_group.rt_bandwidth,
  6506. global_rt_period(), global_rt_runtime());
  6507. #endif /* CONFIG_RT_GROUP_SCHED */
  6508. #ifdef CONFIG_CGROUP_SCHED
  6509. list_add(&init_task_group.list, &task_groups);
  6510. INIT_LIST_HEAD(&init_task_group.children);
  6511. #endif /* CONFIG_CGROUP_SCHED */
  6512. #if defined CONFIG_FAIR_GROUP_SCHED && defined CONFIG_SMP
  6513. update_shares_data = __alloc_percpu(nr_cpu_ids * sizeof(unsigned long),
  6514. __alignof__(unsigned long));
  6515. #endif
  6516. for_each_possible_cpu(i) {
  6517. struct rq *rq;
  6518. rq = cpu_rq(i);
  6519. raw_spin_lock_init(&rq->lock);
  6520. rq->nr_running = 0;
  6521. rq->calc_load_active = 0;
  6522. rq->calc_load_update = jiffies + LOAD_FREQ;
  6523. init_cfs_rq(&rq->cfs, rq);
  6524. init_rt_rq(&rq->rt, rq);
  6525. #ifdef CONFIG_FAIR_GROUP_SCHED
  6526. init_task_group.shares = init_task_group_load;
  6527. INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
  6528. #ifdef CONFIG_CGROUP_SCHED
  6529. /*
  6530. * How much cpu bandwidth does init_task_group get?
  6531. *
  6532. * In case of task-groups formed thr' the cgroup filesystem, it
  6533. * gets 100% of the cpu resources in the system. This overall
  6534. * system cpu resource is divided among the tasks of
  6535. * init_task_group and its child task-groups in a fair manner,
  6536. * based on each entity's (task or task-group's) weight
  6537. * (se->load.weight).
  6538. *
  6539. * In other words, if init_task_group has 10 tasks of weight
  6540. * 1024) and two child groups A0 and A1 (of weight 1024 each),
  6541. * then A0's share of the cpu resource is:
  6542. *
  6543. * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
  6544. *
  6545. * We achieve this by letting init_task_group's tasks sit
  6546. * directly in rq->cfs (i.e init_task_group->se[] = NULL).
  6547. */
  6548. init_tg_cfs_entry(&init_task_group, &rq->cfs, NULL, i, 1, NULL);
  6549. #endif
  6550. #endif /* CONFIG_FAIR_GROUP_SCHED */
  6551. rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime;
  6552. #ifdef CONFIG_RT_GROUP_SCHED
  6553. INIT_LIST_HEAD(&rq->leaf_rt_rq_list);
  6554. #ifdef CONFIG_CGROUP_SCHED
  6555. init_tg_rt_entry(&init_task_group, &rq->rt, NULL, i, 1, NULL);
  6556. #endif
  6557. #endif
  6558. for (j = 0; j < CPU_LOAD_IDX_MAX; j++)
  6559. rq->cpu_load[j] = 0;
  6560. #ifdef CONFIG_SMP
  6561. rq->sd = NULL;
  6562. rq->rd = NULL;
  6563. rq->post_schedule = 0;
  6564. rq->active_balance = 0;
  6565. rq->next_balance = jiffies;
  6566. rq->push_cpu = 0;
  6567. rq->cpu = i;
  6568. rq->online = 0;
  6569. rq->migration_thread = NULL;
  6570. rq->idle_stamp = 0;
  6571. rq->avg_idle = 2*sysctl_sched_migration_cost;
  6572. INIT_LIST_HEAD(&rq->migration_queue);
  6573. rq_attach_root(rq, &def_root_domain);
  6574. #endif
  6575. init_rq_hrtick(rq);
  6576. atomic_set(&rq->nr_iowait, 0);
  6577. }
  6578. set_load_weight(&init_task);
  6579. #ifdef CONFIG_PREEMPT_NOTIFIERS
  6580. INIT_HLIST_HEAD(&init_task.preempt_notifiers);
  6581. #endif
  6582. #ifdef CONFIG_SMP
  6583. open_softirq(SCHED_SOFTIRQ, run_rebalance_domains);
  6584. #endif
  6585. #ifdef CONFIG_RT_MUTEXES
  6586. plist_head_init_raw(&init_task.pi_waiters, &init_task.pi_lock);
  6587. #endif
  6588. /*
  6589. * The boot idle thread does lazy MMU switching as well:
  6590. */
  6591. atomic_inc(&init_mm.mm_count);
  6592. enter_lazy_tlb(&init_mm, current);
  6593. /*
  6594. * Make us the idle thread. Technically, schedule() should not be
  6595. * called from this thread, however somewhere below it might be,
  6596. * but because we are the idle thread, we just pick up running again
  6597. * when this runqueue becomes "idle".
  6598. */
  6599. init_idle(current, smp_processor_id());
  6600. calc_load_update = jiffies + LOAD_FREQ;
  6601. /*
  6602. * During early bootup we pretend to be a normal task:
  6603. */
  6604. current->sched_class = &fair_sched_class;
  6605. /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */
  6606. zalloc_cpumask_var(&nohz_cpu_mask, GFP_NOWAIT);
  6607. #ifdef CONFIG_SMP
  6608. #ifdef CONFIG_NO_HZ
  6609. zalloc_cpumask_var(&nohz.cpu_mask, GFP_NOWAIT);
  6610. alloc_cpumask_var(&nohz.ilb_grp_nohz_mask, GFP_NOWAIT);
  6611. #endif
  6612. /* May be allocated at isolcpus cmdline parse time */
  6613. if (cpu_isolated_map == NULL)
  6614. zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
  6615. #endif /* SMP */
  6616. perf_event_init();
  6617. scheduler_running = 1;
  6618. }
  6619. #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
  6620. static inline int preempt_count_equals(int preempt_offset)
  6621. {
  6622. int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth();
  6623. return (nested == PREEMPT_INATOMIC_BASE + preempt_offset);
  6624. }
  6625. void __might_sleep(const char *file, int line, int preempt_offset)
  6626. {
  6627. #ifdef in_atomic
  6628. static unsigned long prev_jiffy; /* ratelimiting */
  6629. if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) ||
  6630. system_state != SYSTEM_RUNNING || oops_in_progress)
  6631. return;
  6632. if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
  6633. return;
  6634. prev_jiffy = jiffies;
  6635. printk(KERN_ERR
  6636. "BUG: sleeping function called from invalid context at %s:%d\n",
  6637. file, line);
  6638. printk(KERN_ERR
  6639. "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
  6640. in_atomic(), irqs_disabled(),
  6641. current->pid, current->comm);
  6642. debug_show_held_locks(current);
  6643. if (irqs_disabled())
  6644. print_irqtrace_events(current);
  6645. dump_stack();
  6646. #endif
  6647. }
  6648. EXPORT_SYMBOL(__might_sleep);
  6649. #endif
  6650. #ifdef CONFIG_MAGIC_SYSRQ
  6651. static void normalize_task(struct rq *rq, struct task_struct *p)
  6652. {
  6653. int on_rq;
  6654. on_rq = p->se.on_rq;
  6655. if (on_rq)
  6656. deactivate_task(rq, p, 0);
  6657. __setscheduler(rq, p, SCHED_NORMAL, 0);
  6658. if (on_rq) {
  6659. activate_task(rq, p, 0);
  6660. resched_task(rq->curr);
  6661. }
  6662. }
  6663. void normalize_rt_tasks(void)
  6664. {
  6665. struct task_struct *g, *p;
  6666. unsigned long flags;
  6667. struct rq *rq;
  6668. read_lock_irqsave(&tasklist_lock, flags);
  6669. do_each_thread(g, p) {
  6670. /*
  6671. * Only normalize user tasks:
  6672. */
  6673. if (!p->mm)
  6674. continue;
  6675. p->se.exec_start = 0;
  6676. #ifdef CONFIG_SCHEDSTATS
  6677. p->se.statistics.wait_start = 0;
  6678. p->se.statistics.sleep_start = 0;
  6679. p->se.statistics.block_start = 0;
  6680. #endif
  6681. if (!rt_task(p)) {
  6682. /*
  6683. * Renice negative nice level userspace
  6684. * tasks back to 0:
  6685. */
  6686. if (TASK_NICE(p) < 0 && p->mm)
  6687. set_user_nice(p, 0);
  6688. continue;
  6689. }
  6690. raw_spin_lock(&p->pi_lock);
  6691. rq = __task_rq_lock(p);
  6692. normalize_task(rq, p);
  6693. __task_rq_unlock(rq);
  6694. raw_spin_unlock(&p->pi_lock);
  6695. } while_each_thread(g, p);
  6696. read_unlock_irqrestore(&tasklist_lock, flags);
  6697. }
  6698. #endif /* CONFIG_MAGIC_SYSRQ */
  6699. #ifdef CONFIG_IA64
  6700. /*
  6701. * These functions are only useful for the IA64 MCA handling.
  6702. *
  6703. * They can only be called when the whole system has been
  6704. * stopped - every CPU needs to be quiescent, and no scheduling
  6705. * activity can take place. Using them for anything else would
  6706. * be a serious bug, and as a result, they aren't even visible
  6707. * under any other configuration.
  6708. */
  6709. /**
  6710. * curr_task - return the current task for a given cpu.
  6711. * @cpu: the processor in question.
  6712. *
  6713. * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
  6714. */
  6715. struct task_struct *curr_task(int cpu)
  6716. {
  6717. return cpu_curr(cpu);
  6718. }
  6719. /**
  6720. * set_curr_task - set the current task for a given cpu.
  6721. * @cpu: the processor in question.
  6722. * @p: the task pointer to set.
  6723. *
  6724. * Description: This function must only be used when non-maskable interrupts
  6725. * are serviced on a separate stack. It allows the architecture to switch the
  6726. * notion of the current task on a cpu in a non-blocking manner. This function
  6727. * must be called with all CPU's synchronized, and interrupts disabled, the
  6728. * and caller must save the original value of the current task (see
  6729. * curr_task() above) and restore that value before reenabling interrupts and
  6730. * re-starting the system.
  6731. *
  6732. * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
  6733. */
  6734. void set_curr_task(int cpu, struct task_struct *p)
  6735. {
  6736. cpu_curr(cpu) = p;
  6737. }
  6738. #endif
  6739. #ifdef CONFIG_FAIR_GROUP_SCHED
  6740. static void free_fair_sched_group(struct task_group *tg)
  6741. {
  6742. int i;
  6743. for_each_possible_cpu(i) {
  6744. if (tg->cfs_rq)
  6745. kfree(tg->cfs_rq[i]);
  6746. if (tg->se)
  6747. kfree(tg->se[i]);
  6748. }
  6749. kfree(tg->cfs_rq);
  6750. kfree(tg->se);
  6751. }
  6752. static
  6753. int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
  6754. {
  6755. struct cfs_rq *cfs_rq;
  6756. struct sched_entity *se;
  6757. struct rq *rq;
  6758. int i;
  6759. tg->cfs_rq = kzalloc(sizeof(cfs_rq) * nr_cpu_ids, GFP_KERNEL);
  6760. if (!tg->cfs_rq)
  6761. goto err;
  6762. tg->se = kzalloc(sizeof(se) * nr_cpu_ids, GFP_KERNEL);
  6763. if (!tg->se)
  6764. goto err;
  6765. tg->shares = NICE_0_LOAD;
  6766. for_each_possible_cpu(i) {
  6767. rq = cpu_rq(i);
  6768. cfs_rq = kzalloc_node(sizeof(struct cfs_rq),
  6769. GFP_KERNEL, cpu_to_node(i));
  6770. if (!cfs_rq)
  6771. goto err;
  6772. se = kzalloc_node(sizeof(struct sched_entity),
  6773. GFP_KERNEL, cpu_to_node(i));
  6774. if (!se)
  6775. goto err_free_rq;
  6776. init_tg_cfs_entry(tg, cfs_rq, se, i, 0, parent->se[i]);
  6777. }
  6778. return 1;
  6779. err_free_rq:
  6780. kfree(cfs_rq);
  6781. err:
  6782. return 0;
  6783. }
  6784. static inline void register_fair_sched_group(struct task_group *tg, int cpu)
  6785. {
  6786. list_add_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list,
  6787. &cpu_rq(cpu)->leaf_cfs_rq_list);
  6788. }
  6789. static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
  6790. {
  6791. list_del_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list);
  6792. }
  6793. #else /* !CONFG_FAIR_GROUP_SCHED */
  6794. static inline void free_fair_sched_group(struct task_group *tg)
  6795. {
  6796. }
  6797. static inline
  6798. int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
  6799. {
  6800. return 1;
  6801. }
  6802. static inline void register_fair_sched_group(struct task_group *tg, int cpu)
  6803. {
  6804. }
  6805. static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
  6806. {
  6807. }
  6808. #endif /* CONFIG_FAIR_GROUP_SCHED */
  6809. #ifdef CONFIG_RT_GROUP_SCHED
  6810. static void free_rt_sched_group(struct task_group *tg)
  6811. {
  6812. int i;
  6813. destroy_rt_bandwidth(&tg->rt_bandwidth);
  6814. for_each_possible_cpu(i) {
  6815. if (tg->rt_rq)
  6816. kfree(tg->rt_rq[i]);
  6817. if (tg->rt_se)
  6818. kfree(tg->rt_se[i]);
  6819. }
  6820. kfree(tg->rt_rq);
  6821. kfree(tg->rt_se);
  6822. }
  6823. static
  6824. int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
  6825. {
  6826. struct rt_rq *rt_rq;
  6827. struct sched_rt_entity *rt_se;
  6828. struct rq *rq;
  6829. int i;
  6830. tg->rt_rq = kzalloc(sizeof(rt_rq) * nr_cpu_ids, GFP_KERNEL);
  6831. if (!tg->rt_rq)
  6832. goto err;
  6833. tg->rt_se = kzalloc(sizeof(rt_se) * nr_cpu_ids, GFP_KERNEL);
  6834. if (!tg->rt_se)
  6835. goto err;
  6836. init_rt_bandwidth(&tg->rt_bandwidth,
  6837. ktime_to_ns(def_rt_bandwidth.rt_period), 0);
  6838. for_each_possible_cpu(i) {
  6839. rq = cpu_rq(i);
  6840. rt_rq = kzalloc_node(sizeof(struct rt_rq),
  6841. GFP_KERNEL, cpu_to_node(i));
  6842. if (!rt_rq)
  6843. goto err;
  6844. rt_se = kzalloc_node(sizeof(struct sched_rt_entity),
  6845. GFP_KERNEL, cpu_to_node(i));
  6846. if (!rt_se)
  6847. goto err_free_rq;
  6848. init_tg_rt_entry(tg, rt_rq, rt_se, i, 0, parent->rt_se[i]);
  6849. }
  6850. return 1;
  6851. err_free_rq:
  6852. kfree(rt_rq);
  6853. err:
  6854. return 0;
  6855. }
  6856. static inline void register_rt_sched_group(struct task_group *tg, int cpu)
  6857. {
  6858. list_add_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list,
  6859. &cpu_rq(cpu)->leaf_rt_rq_list);
  6860. }
  6861. static inline void unregister_rt_sched_group(struct task_group *tg, int cpu)
  6862. {
  6863. list_del_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list);
  6864. }
  6865. #else /* !CONFIG_RT_GROUP_SCHED */
  6866. static inline void free_rt_sched_group(struct task_group *tg)
  6867. {
  6868. }
  6869. static inline
  6870. int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
  6871. {
  6872. return 1;
  6873. }
  6874. static inline void register_rt_sched_group(struct task_group *tg, int cpu)
  6875. {
  6876. }
  6877. static inline void unregister_rt_sched_group(struct task_group *tg, int cpu)
  6878. {
  6879. }
  6880. #endif /* CONFIG_RT_GROUP_SCHED */
  6881. #ifdef CONFIG_CGROUP_SCHED
  6882. static void free_sched_group(struct task_group *tg)
  6883. {
  6884. free_fair_sched_group(tg);
  6885. free_rt_sched_group(tg);
  6886. kfree(tg);
  6887. }
  6888. /* allocate runqueue etc for a new task group */
  6889. struct task_group *sched_create_group(struct task_group *parent)
  6890. {
  6891. struct task_group *tg;
  6892. unsigned long flags;
  6893. int i;
  6894. tg = kzalloc(sizeof(*tg), GFP_KERNEL);
  6895. if (!tg)
  6896. return ERR_PTR(-ENOMEM);
  6897. if (!alloc_fair_sched_group(tg, parent))
  6898. goto err;
  6899. if (!alloc_rt_sched_group(tg, parent))
  6900. goto err;
  6901. spin_lock_irqsave(&task_group_lock, flags);
  6902. for_each_possible_cpu(i) {
  6903. register_fair_sched_group(tg, i);
  6904. register_rt_sched_group(tg, i);
  6905. }
  6906. list_add_rcu(&tg->list, &task_groups);
  6907. WARN_ON(!parent); /* root should already exist */
  6908. tg->parent = parent;
  6909. INIT_LIST_HEAD(&tg->children);
  6910. list_add_rcu(&tg->siblings, &parent->children);
  6911. spin_unlock_irqrestore(&task_group_lock, flags);
  6912. return tg;
  6913. err:
  6914. free_sched_group(tg);
  6915. return ERR_PTR(-ENOMEM);
  6916. }
  6917. /* rcu callback to free various structures associated with a task group */
  6918. static void free_sched_group_rcu(struct rcu_head *rhp)
  6919. {
  6920. /* now it should be safe to free those cfs_rqs */
  6921. free_sched_group(container_of(rhp, struct task_group, rcu));
  6922. }
  6923. /* Destroy runqueue etc associated with a task group */
  6924. void sched_destroy_group(struct task_group *tg)
  6925. {
  6926. unsigned long flags;
  6927. int i;
  6928. spin_lock_irqsave(&task_group_lock, flags);
  6929. for_each_possible_cpu(i) {
  6930. unregister_fair_sched_group(tg, i);
  6931. unregister_rt_sched_group(tg, i);
  6932. }
  6933. list_del_rcu(&tg->list);
  6934. list_del_rcu(&tg->siblings);
  6935. spin_unlock_irqrestore(&task_group_lock, flags);
  6936. /* wait for possible concurrent references to cfs_rqs complete */
  6937. call_rcu(&tg->rcu, free_sched_group_rcu);
  6938. }
  6939. /* change task's runqueue when it moves between groups.
  6940. * The caller of this function should have put the task in its new group
  6941. * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
  6942. * reflect its new group.
  6943. */
  6944. void sched_move_task(struct task_struct *tsk)
  6945. {
  6946. int on_rq, running;
  6947. unsigned long flags;
  6948. struct rq *rq;
  6949. rq = task_rq_lock(tsk, &flags);
  6950. running = task_current(rq, tsk);
  6951. on_rq = tsk->se.on_rq;
  6952. if (on_rq)
  6953. dequeue_task(rq, tsk, 0);
  6954. if (unlikely(running))
  6955. tsk->sched_class->put_prev_task(rq, tsk);
  6956. set_task_rq(tsk, task_cpu(tsk));
  6957. #ifdef CONFIG_FAIR_GROUP_SCHED
  6958. if (tsk->sched_class->moved_group)
  6959. tsk->sched_class->moved_group(tsk, on_rq);
  6960. #endif
  6961. if (unlikely(running))
  6962. tsk->sched_class->set_curr_task(rq);
  6963. if (on_rq)
  6964. enqueue_task(rq, tsk, 0, false);
  6965. task_rq_unlock(rq, &flags);
  6966. }
  6967. #endif /* CONFIG_CGROUP_SCHED */
  6968. #ifdef CONFIG_FAIR_GROUP_SCHED
  6969. static void __set_se_shares(struct sched_entity *se, unsigned long shares)
  6970. {
  6971. struct cfs_rq *cfs_rq = se->cfs_rq;
  6972. int on_rq;
  6973. on_rq = se->on_rq;
  6974. if (on_rq)
  6975. dequeue_entity(cfs_rq, se, 0);
  6976. se->load.weight = shares;
  6977. se->load.inv_weight = 0;
  6978. if (on_rq)
  6979. enqueue_entity(cfs_rq, se, 0);
  6980. }
  6981. static void set_se_shares(struct sched_entity *se, unsigned long shares)
  6982. {
  6983. struct cfs_rq *cfs_rq = se->cfs_rq;
  6984. struct rq *rq = cfs_rq->rq;
  6985. unsigned long flags;
  6986. raw_spin_lock_irqsave(&rq->lock, flags);
  6987. __set_se_shares(se, shares);
  6988. raw_spin_unlock_irqrestore(&rq->lock, flags);
  6989. }
  6990. static DEFINE_MUTEX(shares_mutex);
  6991. int sched_group_set_shares(struct task_group *tg, unsigned long shares)
  6992. {
  6993. int i;
  6994. unsigned long flags;
  6995. /*
  6996. * We can't change the weight of the root cgroup.
  6997. */
  6998. if (!tg->se[0])
  6999. return -EINVAL;
  7000. if (shares < MIN_SHARES)
  7001. shares = MIN_SHARES;
  7002. else if (shares > MAX_SHARES)
  7003. shares = MAX_SHARES;
  7004. mutex_lock(&shares_mutex);
  7005. if (tg->shares == shares)
  7006. goto done;
  7007. spin_lock_irqsave(&task_group_lock, flags);
  7008. for_each_possible_cpu(i)
  7009. unregister_fair_sched_group(tg, i);
  7010. list_del_rcu(&tg->siblings);
  7011. spin_unlock_irqrestore(&task_group_lock, flags);
  7012. /* wait for any ongoing reference to this group to finish */
  7013. synchronize_sched();
  7014. /*
  7015. * Now we are free to modify the group's share on each cpu
  7016. * w/o tripping rebalance_share or load_balance_fair.
  7017. */
  7018. tg->shares = shares;
  7019. for_each_possible_cpu(i) {
  7020. /*
  7021. * force a rebalance
  7022. */
  7023. cfs_rq_set_shares(tg->cfs_rq[i], 0);
  7024. set_se_shares(tg->se[i], shares);
  7025. }
  7026. /*
  7027. * Enable load balance activity on this group, by inserting it back on
  7028. * each cpu's rq->leaf_cfs_rq_list.
  7029. */
  7030. spin_lock_irqsave(&task_group_lock, flags);
  7031. for_each_possible_cpu(i)
  7032. register_fair_sched_group(tg, i);
  7033. list_add_rcu(&tg->siblings, &tg->parent->children);
  7034. spin_unlock_irqrestore(&task_group_lock, flags);
  7035. done:
  7036. mutex_unlock(&shares_mutex);
  7037. return 0;
  7038. }
  7039. unsigned long sched_group_shares(struct task_group *tg)
  7040. {
  7041. return tg->shares;
  7042. }
  7043. #endif
  7044. #ifdef CONFIG_RT_GROUP_SCHED
  7045. /*
  7046. * Ensure that the real time constraints are schedulable.
  7047. */
  7048. static DEFINE_MUTEX(rt_constraints_mutex);
  7049. static unsigned long to_ratio(u64 period, u64 runtime)
  7050. {
  7051. if (runtime == RUNTIME_INF)
  7052. return 1ULL << 20;
  7053. return div64_u64(runtime << 20, period);
  7054. }
  7055. /* Must be called with tasklist_lock held */
  7056. static inline int tg_has_rt_tasks(struct task_group *tg)
  7057. {
  7058. struct task_struct *g, *p;
  7059. do_each_thread(g, p) {
  7060. if (rt_task(p) && rt_rq_of_se(&p->rt)->tg == tg)
  7061. return 1;
  7062. } while_each_thread(g, p);
  7063. return 0;
  7064. }
  7065. struct rt_schedulable_data {
  7066. struct task_group *tg;
  7067. u64 rt_period;
  7068. u64 rt_runtime;
  7069. };
  7070. static int tg_schedulable(struct task_group *tg, void *data)
  7071. {
  7072. struct rt_schedulable_data *d = data;
  7073. struct task_group *child;
  7074. unsigned long total, sum = 0;
  7075. u64 period, runtime;
  7076. period = ktime_to_ns(tg->rt_bandwidth.rt_period);
  7077. runtime = tg->rt_bandwidth.rt_runtime;
  7078. if (tg == d->tg) {
  7079. period = d->rt_period;
  7080. runtime = d->rt_runtime;
  7081. }
  7082. /*
  7083. * Cannot have more runtime than the period.
  7084. */
  7085. if (runtime > period && runtime != RUNTIME_INF)
  7086. return -EINVAL;
  7087. /*
  7088. * Ensure we don't starve existing RT tasks.
  7089. */
  7090. if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg))
  7091. return -EBUSY;
  7092. total = to_ratio(period, runtime);
  7093. /*
  7094. * Nobody can have more than the global setting allows.
  7095. */
  7096. if (total > to_ratio(global_rt_period(), global_rt_runtime()))
  7097. return -EINVAL;
  7098. /*
  7099. * The sum of our children's runtime should not exceed our own.
  7100. */
  7101. list_for_each_entry_rcu(child, &tg->children, siblings) {
  7102. period = ktime_to_ns(child->rt_bandwidth.rt_period);
  7103. runtime = child->rt_bandwidth.rt_runtime;
  7104. if (child == d->tg) {
  7105. period = d->rt_period;
  7106. runtime = d->rt_runtime;
  7107. }
  7108. sum += to_ratio(period, runtime);
  7109. }
  7110. if (sum > total)
  7111. return -EINVAL;
  7112. return 0;
  7113. }
  7114. static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
  7115. {
  7116. struct rt_schedulable_data data = {
  7117. .tg = tg,
  7118. .rt_period = period,
  7119. .rt_runtime = runtime,
  7120. };
  7121. return walk_tg_tree(tg_schedulable, tg_nop, &data);
  7122. }
  7123. static int tg_set_bandwidth(struct task_group *tg,
  7124. u64 rt_period, u64 rt_runtime)
  7125. {
  7126. int i, err = 0;
  7127. mutex_lock(&rt_constraints_mutex);
  7128. read_lock(&tasklist_lock);
  7129. err = __rt_schedulable(tg, rt_period, rt_runtime);
  7130. if (err)
  7131. goto unlock;
  7132. raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock);
  7133. tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period);
  7134. tg->rt_bandwidth.rt_runtime = rt_runtime;
  7135. for_each_possible_cpu(i) {
  7136. struct rt_rq *rt_rq = tg->rt_rq[i];
  7137. raw_spin_lock(&rt_rq->rt_runtime_lock);
  7138. rt_rq->rt_runtime = rt_runtime;
  7139. raw_spin_unlock(&rt_rq->rt_runtime_lock);
  7140. }
  7141. raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock);
  7142. unlock:
  7143. read_unlock(&tasklist_lock);
  7144. mutex_unlock(&rt_constraints_mutex);
  7145. return err;
  7146. }
  7147. int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us)
  7148. {
  7149. u64 rt_runtime, rt_period;
  7150. rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period);
  7151. rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC;
  7152. if (rt_runtime_us < 0)
  7153. rt_runtime = RUNTIME_INF;
  7154. return tg_set_bandwidth(tg, rt_period, rt_runtime);
  7155. }
  7156. long sched_group_rt_runtime(struct task_group *tg)
  7157. {
  7158. u64 rt_runtime_us;
  7159. if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF)
  7160. return -1;
  7161. rt_runtime_us = tg->rt_bandwidth.rt_runtime;
  7162. do_div(rt_runtime_us, NSEC_PER_USEC);
  7163. return rt_runtime_us;
  7164. }
  7165. int sched_group_set_rt_period(struct task_group *tg, long rt_period_us)
  7166. {
  7167. u64 rt_runtime, rt_period;
  7168. rt_period = (u64)rt_period_us * NSEC_PER_USEC;
  7169. rt_runtime = tg->rt_bandwidth.rt_runtime;
  7170. if (rt_period == 0)
  7171. return -EINVAL;
  7172. return tg_set_bandwidth(tg, rt_period, rt_runtime);
  7173. }
  7174. long sched_group_rt_period(struct task_group *tg)
  7175. {
  7176. u64 rt_period_us;
  7177. rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period);
  7178. do_div(rt_period_us, NSEC_PER_USEC);
  7179. return rt_period_us;
  7180. }
  7181. static int sched_rt_global_constraints(void)
  7182. {
  7183. u64 runtime, period;
  7184. int ret = 0;
  7185. if (sysctl_sched_rt_period <= 0)
  7186. return -EINVAL;
  7187. runtime = global_rt_runtime();
  7188. period = global_rt_period();
  7189. /*
  7190. * Sanity check on the sysctl variables.
  7191. */
  7192. if (runtime > period && runtime != RUNTIME_INF)
  7193. return -EINVAL;
  7194. mutex_lock(&rt_constraints_mutex);
  7195. read_lock(&tasklist_lock);
  7196. ret = __rt_schedulable(NULL, 0, 0);
  7197. read_unlock(&tasklist_lock);
  7198. mutex_unlock(&rt_constraints_mutex);
  7199. return ret;
  7200. }
  7201. int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk)
  7202. {
  7203. /* Don't accept realtime tasks when there is no way for them to run */
  7204. if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0)
  7205. return 0;
  7206. return 1;
  7207. }
  7208. #else /* !CONFIG_RT_GROUP_SCHED */
  7209. static int sched_rt_global_constraints(void)
  7210. {
  7211. unsigned long flags;
  7212. int i;
  7213. if (sysctl_sched_rt_period <= 0)
  7214. return -EINVAL;
  7215. /*
  7216. * There's always some RT tasks in the root group
  7217. * -- migration, kstopmachine etc..
  7218. */
  7219. if (sysctl_sched_rt_runtime == 0)
  7220. return -EBUSY;
  7221. raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
  7222. for_each_possible_cpu(i) {
  7223. struct rt_rq *rt_rq = &cpu_rq(i)->rt;
  7224. raw_spin_lock(&rt_rq->rt_runtime_lock);
  7225. rt_rq->rt_runtime = global_rt_runtime();
  7226. raw_spin_unlock(&rt_rq->rt_runtime_lock);
  7227. }
  7228. raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags);
  7229. return 0;
  7230. }
  7231. #endif /* CONFIG_RT_GROUP_SCHED */
  7232. int sched_rt_handler(struct ctl_table *table, int write,
  7233. void __user *buffer, size_t *lenp,
  7234. loff_t *ppos)
  7235. {
  7236. int ret;
  7237. int old_period, old_runtime;
  7238. static DEFINE_MUTEX(mutex);
  7239. mutex_lock(&mutex);
  7240. old_period = sysctl_sched_rt_period;
  7241. old_runtime = sysctl_sched_rt_runtime;
  7242. ret = proc_dointvec(table, write, buffer, lenp, ppos);
  7243. if (!ret && write) {
  7244. ret = sched_rt_global_constraints();
  7245. if (ret) {
  7246. sysctl_sched_rt_period = old_period;
  7247. sysctl_sched_rt_runtime = old_runtime;
  7248. } else {
  7249. def_rt_bandwidth.rt_runtime = global_rt_runtime();
  7250. def_rt_bandwidth.rt_period =
  7251. ns_to_ktime(global_rt_period());
  7252. }
  7253. }
  7254. mutex_unlock(&mutex);
  7255. return ret;
  7256. }
  7257. #ifdef CONFIG_CGROUP_SCHED
  7258. /* return corresponding task_group object of a cgroup */
  7259. static inline struct task_group *cgroup_tg(struct cgroup *cgrp)
  7260. {
  7261. return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id),
  7262. struct task_group, css);
  7263. }
  7264. static struct cgroup_subsys_state *
  7265. cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp)
  7266. {
  7267. struct task_group *tg, *parent;
  7268. if (!cgrp->parent) {
  7269. /* This is early initialization for the top cgroup */
  7270. return &init_task_group.css;
  7271. }
  7272. parent = cgroup_tg(cgrp->parent);
  7273. tg = sched_create_group(parent);
  7274. if (IS_ERR(tg))
  7275. return ERR_PTR(-ENOMEM);
  7276. return &tg->css;
  7277. }
  7278. static void
  7279. cpu_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
  7280. {
  7281. struct task_group *tg = cgroup_tg(cgrp);
  7282. sched_destroy_group(tg);
  7283. }
  7284. static int
  7285. cpu_cgroup_can_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
  7286. {
  7287. #ifdef CONFIG_RT_GROUP_SCHED
  7288. if (!sched_rt_can_attach(cgroup_tg(cgrp), tsk))
  7289. return -EINVAL;
  7290. #else
  7291. /* We don't support RT-tasks being in separate groups */
  7292. if (tsk->sched_class != &fair_sched_class)
  7293. return -EINVAL;
  7294. #endif
  7295. return 0;
  7296. }
  7297. static int
  7298. cpu_cgroup_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
  7299. struct task_struct *tsk, bool threadgroup)
  7300. {
  7301. int retval = cpu_cgroup_can_attach_task(cgrp, tsk);
  7302. if (retval)
  7303. return retval;
  7304. if (threadgroup) {
  7305. struct task_struct *c;
  7306. rcu_read_lock();
  7307. list_for_each_entry_rcu(c, &tsk->thread_group, thread_group) {
  7308. retval = cpu_cgroup_can_attach_task(cgrp, c);
  7309. if (retval) {
  7310. rcu_read_unlock();
  7311. return retval;
  7312. }
  7313. }
  7314. rcu_read_unlock();
  7315. }
  7316. return 0;
  7317. }
  7318. static void
  7319. cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
  7320. struct cgroup *old_cont, struct task_struct *tsk,
  7321. bool threadgroup)
  7322. {
  7323. sched_move_task(tsk);
  7324. if (threadgroup) {
  7325. struct task_struct *c;
  7326. rcu_read_lock();
  7327. list_for_each_entry_rcu(c, &tsk->thread_group, thread_group) {
  7328. sched_move_task(c);
  7329. }
  7330. rcu_read_unlock();
  7331. }
  7332. }
  7333. #ifdef CONFIG_FAIR_GROUP_SCHED
  7334. static int cpu_shares_write_u64(struct cgroup *cgrp, struct cftype *cftype,
  7335. u64 shareval)
  7336. {
  7337. return sched_group_set_shares(cgroup_tg(cgrp), shareval);
  7338. }
  7339. static u64 cpu_shares_read_u64(struct cgroup *cgrp, struct cftype *cft)
  7340. {
  7341. struct task_group *tg = cgroup_tg(cgrp);
  7342. return (u64) tg->shares;
  7343. }
  7344. #endif /* CONFIG_FAIR_GROUP_SCHED */
  7345. #ifdef CONFIG_RT_GROUP_SCHED
  7346. static int cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft,
  7347. s64 val)
  7348. {
  7349. return sched_group_set_rt_runtime(cgroup_tg(cgrp), val);
  7350. }
  7351. static s64 cpu_rt_runtime_read(struct cgroup *cgrp, struct cftype *cft)
  7352. {
  7353. return sched_group_rt_runtime(cgroup_tg(cgrp));
  7354. }
  7355. static int cpu_rt_period_write_uint(struct cgroup *cgrp, struct cftype *cftype,
  7356. u64 rt_period_us)
  7357. {
  7358. return sched_group_set_rt_period(cgroup_tg(cgrp), rt_period_us);
  7359. }
  7360. static u64 cpu_rt_period_read_uint(struct cgroup *cgrp, struct cftype *cft)
  7361. {
  7362. return sched_group_rt_period(cgroup_tg(cgrp));
  7363. }
  7364. #endif /* CONFIG_RT_GROUP_SCHED */
  7365. static struct cftype cpu_files[] = {
  7366. #ifdef CONFIG_FAIR_GROUP_SCHED
  7367. {
  7368. .name = "shares",
  7369. .read_u64 = cpu_shares_read_u64,
  7370. .write_u64 = cpu_shares_write_u64,
  7371. },
  7372. #endif
  7373. #ifdef CONFIG_RT_GROUP_SCHED
  7374. {
  7375. .name = "rt_runtime_us",
  7376. .read_s64 = cpu_rt_runtime_read,
  7377. .write_s64 = cpu_rt_runtime_write,
  7378. },
  7379. {
  7380. .name = "rt_period_us",
  7381. .read_u64 = cpu_rt_period_read_uint,
  7382. .write_u64 = cpu_rt_period_write_uint,
  7383. },
  7384. #endif
  7385. };
  7386. static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont)
  7387. {
  7388. return cgroup_add_files(cont, ss, cpu_files, ARRAY_SIZE(cpu_files));
  7389. }
  7390. struct cgroup_subsys cpu_cgroup_subsys = {
  7391. .name = "cpu",
  7392. .create = cpu_cgroup_create,
  7393. .destroy = cpu_cgroup_destroy,
  7394. .can_attach = cpu_cgroup_can_attach,
  7395. .attach = cpu_cgroup_attach,
  7396. .populate = cpu_cgroup_populate,
  7397. .subsys_id = cpu_cgroup_subsys_id,
  7398. .early_init = 1,
  7399. };
  7400. #endif /* CONFIG_CGROUP_SCHED */
  7401. #ifdef CONFIG_CGROUP_CPUACCT
  7402. /*
  7403. * CPU accounting code for task groups.
  7404. *
  7405. * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
  7406. * (balbir@in.ibm.com).
  7407. */
  7408. /* track cpu usage of a group of tasks and its child groups */
  7409. struct cpuacct {
  7410. struct cgroup_subsys_state css;
  7411. /* cpuusage holds pointer to a u64-type object on every cpu */
  7412. u64 *cpuusage;
  7413. struct percpu_counter cpustat[CPUACCT_STAT_NSTATS];
  7414. struct cpuacct *parent;
  7415. };
  7416. struct cgroup_subsys cpuacct_subsys;
  7417. /* return cpu accounting group corresponding to this container */
  7418. static inline struct cpuacct *cgroup_ca(struct cgroup *cgrp)
  7419. {
  7420. return container_of(cgroup_subsys_state(cgrp, cpuacct_subsys_id),
  7421. struct cpuacct, css);
  7422. }
  7423. /* return cpu accounting group to which this task belongs */
  7424. static inline struct cpuacct *task_ca(struct task_struct *tsk)
  7425. {
  7426. return container_of(task_subsys_state(tsk, cpuacct_subsys_id),
  7427. struct cpuacct, css);
  7428. }
  7429. /* create a new cpu accounting group */
  7430. static struct cgroup_subsys_state *cpuacct_create(
  7431. struct cgroup_subsys *ss, struct cgroup *cgrp)
  7432. {
  7433. struct cpuacct *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
  7434. int i;
  7435. if (!ca)
  7436. goto out;
  7437. ca->cpuusage = alloc_percpu(u64);
  7438. if (!ca->cpuusage)
  7439. goto out_free_ca;
  7440. for (i = 0; i < CPUACCT_STAT_NSTATS; i++)
  7441. if (percpu_counter_init(&ca->cpustat[i], 0))
  7442. goto out_free_counters;
  7443. if (cgrp->parent)
  7444. ca->parent = cgroup_ca(cgrp->parent);
  7445. return &ca->css;
  7446. out_free_counters:
  7447. while (--i >= 0)
  7448. percpu_counter_destroy(&ca->cpustat[i]);
  7449. free_percpu(ca->cpuusage);
  7450. out_free_ca:
  7451. kfree(ca);
  7452. out:
  7453. return ERR_PTR(-ENOMEM);
  7454. }
  7455. /* destroy an existing cpu accounting group */
  7456. static void
  7457. cpuacct_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
  7458. {
  7459. struct cpuacct *ca = cgroup_ca(cgrp);
  7460. int i;
  7461. for (i = 0; i < CPUACCT_STAT_NSTATS; i++)
  7462. percpu_counter_destroy(&ca->cpustat[i]);
  7463. free_percpu(ca->cpuusage);
  7464. kfree(ca);
  7465. }
  7466. static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu)
  7467. {
  7468. u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
  7469. u64 data;
  7470. #ifndef CONFIG_64BIT
  7471. /*
  7472. * Take rq->lock to make 64-bit read safe on 32-bit platforms.
  7473. */
  7474. raw_spin_lock_irq(&cpu_rq(cpu)->lock);
  7475. data = *cpuusage;
  7476. raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
  7477. #else
  7478. data = *cpuusage;
  7479. #endif
  7480. return data;
  7481. }
  7482. static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val)
  7483. {
  7484. u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
  7485. #ifndef CONFIG_64BIT
  7486. /*
  7487. * Take rq->lock to make 64-bit write safe on 32-bit platforms.
  7488. */
  7489. raw_spin_lock_irq(&cpu_rq(cpu)->lock);
  7490. *cpuusage = val;
  7491. raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
  7492. #else
  7493. *cpuusage = val;
  7494. #endif
  7495. }
  7496. /* return total cpu usage (in nanoseconds) of a group */
  7497. static u64 cpuusage_read(struct cgroup *cgrp, struct cftype *cft)
  7498. {
  7499. struct cpuacct *ca = cgroup_ca(cgrp);
  7500. u64 totalcpuusage = 0;
  7501. int i;
  7502. for_each_present_cpu(i)
  7503. totalcpuusage += cpuacct_cpuusage_read(ca, i);
  7504. return totalcpuusage;
  7505. }
  7506. static int cpuusage_write(struct cgroup *cgrp, struct cftype *cftype,
  7507. u64 reset)
  7508. {
  7509. struct cpuacct *ca = cgroup_ca(cgrp);
  7510. int err = 0;
  7511. int i;
  7512. if (reset) {
  7513. err = -EINVAL;
  7514. goto out;
  7515. }
  7516. for_each_present_cpu(i)
  7517. cpuacct_cpuusage_write(ca, i, 0);
  7518. out:
  7519. return err;
  7520. }
  7521. static int cpuacct_percpu_seq_read(struct cgroup *cgroup, struct cftype *cft,
  7522. struct seq_file *m)
  7523. {
  7524. struct cpuacct *ca = cgroup_ca(cgroup);
  7525. u64 percpu;
  7526. int i;
  7527. for_each_present_cpu(i) {
  7528. percpu = cpuacct_cpuusage_read(ca, i);
  7529. seq_printf(m, "%llu ", (unsigned long long) percpu);
  7530. }
  7531. seq_printf(m, "\n");
  7532. return 0;
  7533. }
  7534. static const char *cpuacct_stat_desc[] = {
  7535. [CPUACCT_STAT_USER] = "user",
  7536. [CPUACCT_STAT_SYSTEM] = "system",
  7537. };
  7538. static int cpuacct_stats_show(struct cgroup *cgrp, struct cftype *cft,
  7539. struct cgroup_map_cb *cb)
  7540. {
  7541. struct cpuacct *ca = cgroup_ca(cgrp);
  7542. int i;
  7543. for (i = 0; i < CPUACCT_STAT_NSTATS; i++) {
  7544. s64 val = percpu_counter_read(&ca->cpustat[i]);
  7545. val = cputime64_to_clock_t(val);
  7546. cb->fill(cb, cpuacct_stat_desc[i], val);
  7547. }
  7548. return 0;
  7549. }
  7550. static struct cftype files[] = {
  7551. {
  7552. .name = "usage",
  7553. .read_u64 = cpuusage_read,
  7554. .write_u64 = cpuusage_write,
  7555. },
  7556. {
  7557. .name = "usage_percpu",
  7558. .read_seq_string = cpuacct_percpu_seq_read,
  7559. },
  7560. {
  7561. .name = "stat",
  7562. .read_map = cpuacct_stats_show,
  7563. },
  7564. };
  7565. static int cpuacct_populate(struct cgroup_subsys *ss, struct cgroup *cgrp)
  7566. {
  7567. return cgroup_add_files(cgrp, ss, files, ARRAY_SIZE(files));
  7568. }
  7569. /*
  7570. * charge this task's execution time to its accounting group.
  7571. *
  7572. * called with rq->lock held.
  7573. */
  7574. static void cpuacct_charge(struct task_struct *tsk, u64 cputime)
  7575. {
  7576. struct cpuacct *ca;
  7577. int cpu;
  7578. if (unlikely(!cpuacct_subsys.active))
  7579. return;
  7580. cpu = task_cpu(tsk);
  7581. rcu_read_lock();
  7582. ca = task_ca(tsk);
  7583. for (; ca; ca = ca->parent) {
  7584. u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
  7585. *cpuusage += cputime;
  7586. }
  7587. rcu_read_unlock();
  7588. }
  7589. /*
  7590. * When CONFIG_VIRT_CPU_ACCOUNTING is enabled one jiffy can be very large
  7591. * in cputime_t units. As a result, cpuacct_update_stats calls
  7592. * percpu_counter_add with values large enough to always overflow the
  7593. * per cpu batch limit causing bad SMP scalability.
  7594. *
  7595. * To fix this we scale percpu_counter_batch by cputime_one_jiffy so we
  7596. * batch the same amount of time with CONFIG_VIRT_CPU_ACCOUNTING disabled
  7597. * and enabled. We cap it at INT_MAX which is the largest allowed batch value.
  7598. */
  7599. #ifdef CONFIG_SMP
  7600. #define CPUACCT_BATCH \
  7601. min_t(long, percpu_counter_batch * cputime_one_jiffy, INT_MAX)
  7602. #else
  7603. #define CPUACCT_BATCH 0
  7604. #endif
  7605. /*
  7606. * Charge the system/user time to the task's accounting group.
  7607. */
  7608. static void cpuacct_update_stats(struct task_struct *tsk,
  7609. enum cpuacct_stat_index idx, cputime_t val)
  7610. {
  7611. struct cpuacct *ca;
  7612. int batch = CPUACCT_BATCH;
  7613. if (unlikely(!cpuacct_subsys.active))
  7614. return;
  7615. rcu_read_lock();
  7616. ca = task_ca(tsk);
  7617. do {
  7618. __percpu_counter_add(&ca->cpustat[idx], val, batch);
  7619. ca = ca->parent;
  7620. } while (ca);
  7621. rcu_read_unlock();
  7622. }
  7623. struct cgroup_subsys cpuacct_subsys = {
  7624. .name = "cpuacct",
  7625. .create = cpuacct_create,
  7626. .destroy = cpuacct_destroy,
  7627. .populate = cpuacct_populate,
  7628. .subsys_id = cpuacct_subsys_id,
  7629. };
  7630. #endif /* CONFIG_CGROUP_CPUACCT */
  7631. #ifndef CONFIG_SMP
  7632. int rcu_expedited_torture_stats(char *page)
  7633. {
  7634. return 0;
  7635. }
  7636. EXPORT_SYMBOL_GPL(rcu_expedited_torture_stats);
  7637. void synchronize_sched_expedited(void)
  7638. {
  7639. }
  7640. EXPORT_SYMBOL_GPL(synchronize_sched_expedited);
  7641. #else /* #ifndef CONFIG_SMP */
  7642. static DEFINE_PER_CPU(struct migration_req, rcu_migration_req);
  7643. static DEFINE_MUTEX(rcu_sched_expedited_mutex);
  7644. #define RCU_EXPEDITED_STATE_POST -2
  7645. #define RCU_EXPEDITED_STATE_IDLE -1
  7646. static int rcu_expedited_state = RCU_EXPEDITED_STATE_IDLE;
  7647. int rcu_expedited_torture_stats(char *page)
  7648. {
  7649. int cnt = 0;
  7650. int cpu;
  7651. cnt += sprintf(&page[cnt], "state: %d /", rcu_expedited_state);
  7652. for_each_online_cpu(cpu) {
  7653. cnt += sprintf(&page[cnt], " %d:%d",
  7654. cpu, per_cpu(rcu_migration_req, cpu).dest_cpu);
  7655. }
  7656. cnt += sprintf(&page[cnt], "\n");
  7657. return cnt;
  7658. }
  7659. EXPORT_SYMBOL_GPL(rcu_expedited_torture_stats);
  7660. static long synchronize_sched_expedited_count;
  7661. /*
  7662. * Wait for an rcu-sched grace period to elapse, but use "big hammer"
  7663. * approach to force grace period to end quickly. This consumes
  7664. * significant time on all CPUs, and is thus not recommended for
  7665. * any sort of common-case code.
  7666. *
  7667. * Note that it is illegal to call this function while holding any
  7668. * lock that is acquired by a CPU-hotplug notifier. Failing to
  7669. * observe this restriction will result in deadlock.
  7670. */
  7671. void synchronize_sched_expedited(void)
  7672. {
  7673. int cpu;
  7674. unsigned long flags;
  7675. bool need_full_sync = 0;
  7676. struct rq *rq;
  7677. struct migration_req *req;
  7678. long snap;
  7679. int trycount = 0;
  7680. smp_mb(); /* ensure prior mod happens before capturing snap. */
  7681. snap = ACCESS_ONCE(synchronize_sched_expedited_count) + 1;
  7682. get_online_cpus();
  7683. while (!mutex_trylock(&rcu_sched_expedited_mutex)) {
  7684. put_online_cpus();
  7685. if (trycount++ < 10)
  7686. udelay(trycount * num_online_cpus());
  7687. else {
  7688. synchronize_sched();
  7689. return;
  7690. }
  7691. if (ACCESS_ONCE(synchronize_sched_expedited_count) - snap > 0) {
  7692. smp_mb(); /* ensure test happens before caller kfree */
  7693. return;
  7694. }
  7695. get_online_cpus();
  7696. }
  7697. rcu_expedited_state = RCU_EXPEDITED_STATE_POST;
  7698. for_each_online_cpu(cpu) {
  7699. rq = cpu_rq(cpu);
  7700. req = &per_cpu(rcu_migration_req, cpu);
  7701. init_completion(&req->done);
  7702. req->task = NULL;
  7703. req->dest_cpu = RCU_MIGRATION_NEED_QS;
  7704. raw_spin_lock_irqsave(&rq->lock, flags);
  7705. list_add(&req->list, &rq->migration_queue);
  7706. raw_spin_unlock_irqrestore(&rq->lock, flags);
  7707. wake_up_process(rq->migration_thread);
  7708. }
  7709. for_each_online_cpu(cpu) {
  7710. rcu_expedited_state = cpu;
  7711. req = &per_cpu(rcu_migration_req, cpu);
  7712. rq = cpu_rq(cpu);
  7713. wait_for_completion(&req->done);
  7714. raw_spin_lock_irqsave(&rq->lock, flags);
  7715. if (unlikely(req->dest_cpu == RCU_MIGRATION_MUST_SYNC))
  7716. need_full_sync = 1;
  7717. req->dest_cpu = RCU_MIGRATION_IDLE;
  7718. raw_spin_unlock_irqrestore(&rq->lock, flags);
  7719. }
  7720. rcu_expedited_state = RCU_EXPEDITED_STATE_IDLE;
  7721. synchronize_sched_expedited_count++;
  7722. mutex_unlock(&rcu_sched_expedited_mutex);
  7723. put_online_cpus();
  7724. if (need_full_sync)
  7725. synchronize_sched();
  7726. }
  7727. EXPORT_SYMBOL_GPL(synchronize_sched_expedited);
  7728. #endif /* #else #ifndef CONFIG_SMP */