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. /* capture load from *all* tasks on this cpu: */
  418. struct load_weight load;
  419. unsigned long nr_load_updates;
  420. u64 nr_switches;
  421. struct cfs_rq cfs;
  422. struct rt_rq rt;
  423. #ifdef CONFIG_FAIR_GROUP_SCHED
  424. /* list of leaf cfs_rq on this cpu: */
  425. struct list_head leaf_cfs_rq_list;
  426. #endif
  427. #ifdef CONFIG_RT_GROUP_SCHED
  428. struct list_head leaf_rt_rq_list;
  429. #endif
  430. /*
  431. * This is part of a global counter where only the total sum
  432. * over all CPUs matters. A task can increase this counter on
  433. * one CPU and if it got migrated afterwards it may decrease
  434. * it on another CPU. Always updated under the runqueue lock:
  435. */
  436. unsigned long nr_uninterruptible;
  437. struct task_struct *curr, *idle;
  438. unsigned long next_balance;
  439. struct mm_struct *prev_mm;
  440. u64 clock;
  441. atomic_t nr_iowait;
  442. #ifdef CONFIG_SMP
  443. struct root_domain *rd;
  444. struct sched_domain *sd;
  445. unsigned char idle_at_tick;
  446. /* For active balancing */
  447. int post_schedule;
  448. int active_balance;
  449. int push_cpu;
  450. /* cpu of this runqueue: */
  451. int cpu;
  452. int online;
  453. unsigned long avg_load_per_task;
  454. struct task_struct *migration_thread;
  455. struct list_head migration_queue;
  456. u64 rt_avg;
  457. u64 age_stamp;
  458. u64 idle_stamp;
  459. u64 avg_idle;
  460. #endif
  461. /* calc_load related fields */
  462. unsigned long calc_load_update;
  463. long calc_load_active;
  464. #ifdef CONFIG_SCHED_HRTICK
  465. #ifdef CONFIG_SMP
  466. int hrtick_csd_pending;
  467. struct call_single_data hrtick_csd;
  468. #endif
  469. struct hrtimer hrtick_timer;
  470. #endif
  471. #ifdef CONFIG_SCHEDSTATS
  472. /* latency stats */
  473. struct sched_info rq_sched_info;
  474. unsigned long long rq_cpu_time;
  475. /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
  476. /* sys_sched_yield() stats */
  477. unsigned int yld_count;
  478. /* schedule() stats */
  479. unsigned int sched_switch;
  480. unsigned int sched_count;
  481. unsigned int sched_goidle;
  482. /* try_to_wake_up() stats */
  483. unsigned int ttwu_count;
  484. unsigned int ttwu_local;
  485. /* BKL stats */
  486. unsigned int bkl_count;
  487. #endif
  488. };
  489. static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
  490. static inline
  491. void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags)
  492. {
  493. rq->curr->sched_class->check_preempt_curr(rq, p, flags);
  494. }
  495. static inline int cpu_of(struct rq *rq)
  496. {
  497. #ifdef CONFIG_SMP
  498. return rq->cpu;
  499. #else
  500. return 0;
  501. #endif
  502. }
  503. #define rcu_dereference_check_sched_domain(p) \
  504. rcu_dereference_check((p), \
  505. rcu_read_lock_sched_held() || \
  506. lockdep_is_held(&sched_domains_mutex))
  507. /*
  508. * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
  509. * See detach_destroy_domains: synchronize_sched for details.
  510. *
  511. * The domain tree of any CPU may only be accessed from within
  512. * preempt-disabled sections.
  513. */
  514. #define for_each_domain(cpu, __sd) \
  515. for (__sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
  516. #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
  517. #define this_rq() (&__get_cpu_var(runqueues))
  518. #define task_rq(p) cpu_rq(task_cpu(p))
  519. #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
  520. #define raw_rq() (&__raw_get_cpu_var(runqueues))
  521. inline void update_rq_clock(struct rq *rq)
  522. {
  523. rq->clock = sched_clock_cpu(cpu_of(rq));
  524. }
  525. /*
  526. * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
  527. */
  528. #ifdef CONFIG_SCHED_DEBUG
  529. # define const_debug __read_mostly
  530. #else
  531. # define const_debug static const
  532. #endif
  533. /**
  534. * runqueue_is_locked
  535. * @cpu: the processor in question.
  536. *
  537. * Returns true if the current cpu runqueue is locked.
  538. * This interface allows printk to be called with the runqueue lock
  539. * held and know whether or not it is OK to wake up the klogd.
  540. */
  541. int runqueue_is_locked(int cpu)
  542. {
  543. return raw_spin_is_locked(&cpu_rq(cpu)->lock);
  544. }
  545. /*
  546. * Debugging: various feature bits
  547. */
  548. #define SCHED_FEAT(name, enabled) \
  549. __SCHED_FEAT_##name ,
  550. enum {
  551. #include "sched_features.h"
  552. };
  553. #undef SCHED_FEAT
  554. #define SCHED_FEAT(name, enabled) \
  555. (1UL << __SCHED_FEAT_##name) * enabled |
  556. const_debug unsigned int sysctl_sched_features =
  557. #include "sched_features.h"
  558. 0;
  559. #undef SCHED_FEAT
  560. #ifdef CONFIG_SCHED_DEBUG
  561. #define SCHED_FEAT(name, enabled) \
  562. #name ,
  563. static __read_mostly char *sched_feat_names[] = {
  564. #include "sched_features.h"
  565. NULL
  566. };
  567. #undef SCHED_FEAT
  568. static int sched_feat_show(struct seq_file *m, void *v)
  569. {
  570. int i;
  571. for (i = 0; sched_feat_names[i]; i++) {
  572. if (!(sysctl_sched_features & (1UL << i)))
  573. seq_puts(m, "NO_");
  574. seq_printf(m, "%s ", sched_feat_names[i]);
  575. }
  576. seq_puts(m, "\n");
  577. return 0;
  578. }
  579. static ssize_t
  580. sched_feat_write(struct file *filp, const char __user *ubuf,
  581. size_t cnt, loff_t *ppos)
  582. {
  583. char buf[64];
  584. char *cmp = buf;
  585. int neg = 0;
  586. int i;
  587. if (cnt > 63)
  588. cnt = 63;
  589. if (copy_from_user(&buf, ubuf, cnt))
  590. return -EFAULT;
  591. buf[cnt] = 0;
  592. if (strncmp(buf, "NO_", 3) == 0) {
  593. neg = 1;
  594. cmp += 3;
  595. }
  596. for (i = 0; sched_feat_names[i]; i++) {
  597. int len = strlen(sched_feat_names[i]);
  598. if (strncmp(cmp, sched_feat_names[i], len) == 0) {
  599. if (neg)
  600. sysctl_sched_features &= ~(1UL << i);
  601. else
  602. sysctl_sched_features |= (1UL << i);
  603. break;
  604. }
  605. }
  606. if (!sched_feat_names[i])
  607. return -EINVAL;
  608. *ppos += cnt;
  609. return cnt;
  610. }
  611. static int sched_feat_open(struct inode *inode, struct file *filp)
  612. {
  613. return single_open(filp, sched_feat_show, NULL);
  614. }
  615. static const struct file_operations sched_feat_fops = {
  616. .open = sched_feat_open,
  617. .write = sched_feat_write,
  618. .read = seq_read,
  619. .llseek = seq_lseek,
  620. .release = single_release,
  621. };
  622. static __init int sched_init_debug(void)
  623. {
  624. debugfs_create_file("sched_features", 0644, NULL, NULL,
  625. &sched_feat_fops);
  626. return 0;
  627. }
  628. late_initcall(sched_init_debug);
  629. #endif
  630. #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
  631. /*
  632. * Number of tasks to iterate in a single balance run.
  633. * Limited because this is done with IRQs disabled.
  634. */
  635. const_debug unsigned int sysctl_sched_nr_migrate = 32;
  636. /*
  637. * ratelimit for updating the group shares.
  638. * default: 0.25ms
  639. */
  640. unsigned int sysctl_sched_shares_ratelimit = 250000;
  641. unsigned int normalized_sysctl_sched_shares_ratelimit = 250000;
  642. /*
  643. * Inject some fuzzyness into changing the per-cpu group shares
  644. * this avoids remote rq-locks at the expense of fairness.
  645. * default: 4
  646. */
  647. unsigned int sysctl_sched_shares_thresh = 4;
  648. /*
  649. * period over which we average the RT time consumption, measured
  650. * in ms.
  651. *
  652. * default: 1s
  653. */
  654. const_debug unsigned int sysctl_sched_time_avg = MSEC_PER_SEC;
  655. /*
  656. * period over which we measure -rt task cpu usage in us.
  657. * default: 1s
  658. */
  659. unsigned int sysctl_sched_rt_period = 1000000;
  660. static __read_mostly int scheduler_running;
  661. /*
  662. * part of the period that we allow rt tasks to run in us.
  663. * default: 0.95s
  664. */
  665. int sysctl_sched_rt_runtime = 950000;
  666. static inline u64 global_rt_period(void)
  667. {
  668. return (u64)sysctl_sched_rt_period * NSEC_PER_USEC;
  669. }
  670. static inline u64 global_rt_runtime(void)
  671. {
  672. if (sysctl_sched_rt_runtime < 0)
  673. return RUNTIME_INF;
  674. return (u64)sysctl_sched_rt_runtime * NSEC_PER_USEC;
  675. }
  676. #ifndef prepare_arch_switch
  677. # define prepare_arch_switch(next) do { } while (0)
  678. #endif
  679. #ifndef finish_arch_switch
  680. # define finish_arch_switch(prev) do { } while (0)
  681. #endif
  682. static inline int task_current(struct rq *rq, struct task_struct *p)
  683. {
  684. return rq->curr == p;
  685. }
  686. #ifndef __ARCH_WANT_UNLOCKED_CTXSW
  687. static inline int task_running(struct rq *rq, struct task_struct *p)
  688. {
  689. return task_current(rq, p);
  690. }
  691. static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
  692. {
  693. }
  694. static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
  695. {
  696. #ifdef CONFIG_DEBUG_SPINLOCK
  697. /* this is a valid case when another task releases the spinlock */
  698. rq->lock.owner = current;
  699. #endif
  700. /*
  701. * If we are tracking spinlock dependencies then we have to
  702. * fix up the runqueue lock - which gets 'carried over' from
  703. * prev into current:
  704. */
  705. spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_);
  706. raw_spin_unlock_irq(&rq->lock);
  707. }
  708. #else /* __ARCH_WANT_UNLOCKED_CTXSW */
  709. static inline int task_running(struct rq *rq, struct task_struct *p)
  710. {
  711. #ifdef CONFIG_SMP
  712. return p->oncpu;
  713. #else
  714. return task_current(rq, p);
  715. #endif
  716. }
  717. static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
  718. {
  719. #ifdef CONFIG_SMP
  720. /*
  721. * We can optimise this out completely for !SMP, because the
  722. * SMP rebalancing from interrupt is the only thing that cares
  723. * here.
  724. */
  725. next->oncpu = 1;
  726. #endif
  727. #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
  728. raw_spin_unlock_irq(&rq->lock);
  729. #else
  730. raw_spin_unlock(&rq->lock);
  731. #endif
  732. }
  733. static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
  734. {
  735. #ifdef CONFIG_SMP
  736. /*
  737. * After ->oncpu is cleared, the task can be moved to a different CPU.
  738. * We must ensure this doesn't happen until the switch is completely
  739. * finished.
  740. */
  741. smp_wmb();
  742. prev->oncpu = 0;
  743. #endif
  744. #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
  745. local_irq_enable();
  746. #endif
  747. }
  748. #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
  749. /*
  750. * Check whether the task is waking, we use this to synchronize against
  751. * ttwu() so that task_cpu() reports a stable number.
  752. *
  753. * We need to make an exception for PF_STARTING tasks because the fork
  754. * path might require task_rq_lock() to work, eg. it can call
  755. * set_cpus_allowed_ptr() from the cpuset clone_ns code.
  756. */
  757. static inline int task_is_waking(struct task_struct *p)
  758. {
  759. return unlikely((p->state == TASK_WAKING) && !(p->flags & PF_STARTING));
  760. }
  761. /*
  762. * __task_rq_lock - lock the runqueue a given task resides on.
  763. * Must be called interrupts disabled.
  764. */
  765. static inline struct rq *__task_rq_lock(struct task_struct *p)
  766. __acquires(rq->lock)
  767. {
  768. struct rq *rq;
  769. for (;;) {
  770. while (task_is_waking(p))
  771. cpu_relax();
  772. rq = task_rq(p);
  773. raw_spin_lock(&rq->lock);
  774. if (likely(rq == task_rq(p) && !task_is_waking(p)))
  775. return rq;
  776. raw_spin_unlock(&rq->lock);
  777. }
  778. }
  779. /*
  780. * task_rq_lock - lock the runqueue a given task resides on and disable
  781. * interrupts. Note the ordering: we can safely lookup the task_rq without
  782. * explicitly disabling preemption.
  783. */
  784. static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags)
  785. __acquires(rq->lock)
  786. {
  787. struct rq *rq;
  788. for (;;) {
  789. while (task_is_waking(p))
  790. cpu_relax();
  791. local_irq_save(*flags);
  792. rq = task_rq(p);
  793. raw_spin_lock(&rq->lock);
  794. if (likely(rq == task_rq(p) && !task_is_waking(p)))
  795. return rq;
  796. raw_spin_unlock_irqrestore(&rq->lock, *flags);
  797. }
  798. }
  799. void task_rq_unlock_wait(struct task_struct *p)
  800. {
  801. struct rq *rq = task_rq(p);
  802. smp_mb(); /* spin-unlock-wait is not a full memory barrier */
  803. raw_spin_unlock_wait(&rq->lock);
  804. }
  805. static void __task_rq_unlock(struct rq *rq)
  806. __releases(rq->lock)
  807. {
  808. raw_spin_unlock(&rq->lock);
  809. }
  810. static inline void task_rq_unlock(struct rq *rq, unsigned long *flags)
  811. __releases(rq->lock)
  812. {
  813. raw_spin_unlock_irqrestore(&rq->lock, *flags);
  814. }
  815. /*
  816. * this_rq_lock - lock this runqueue and disable interrupts.
  817. */
  818. static struct rq *this_rq_lock(void)
  819. __acquires(rq->lock)
  820. {
  821. struct rq *rq;
  822. local_irq_disable();
  823. rq = this_rq();
  824. raw_spin_lock(&rq->lock);
  825. return rq;
  826. }
  827. #ifdef CONFIG_SCHED_HRTICK
  828. /*
  829. * Use HR-timers to deliver accurate preemption points.
  830. *
  831. * Its all a bit involved since we cannot program an hrt while holding the
  832. * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
  833. * reschedule event.
  834. *
  835. * When we get rescheduled we reprogram the hrtick_timer outside of the
  836. * rq->lock.
  837. */
  838. /*
  839. * Use hrtick when:
  840. * - enabled by features
  841. * - hrtimer is actually high res
  842. */
  843. static inline int hrtick_enabled(struct rq *rq)
  844. {
  845. if (!sched_feat(HRTICK))
  846. return 0;
  847. if (!cpu_active(cpu_of(rq)))
  848. return 0;
  849. return hrtimer_is_hres_active(&rq->hrtick_timer);
  850. }
  851. static void hrtick_clear(struct rq *rq)
  852. {
  853. if (hrtimer_active(&rq->hrtick_timer))
  854. hrtimer_cancel(&rq->hrtick_timer);
  855. }
  856. /*
  857. * High-resolution timer tick.
  858. * Runs from hardirq context with interrupts disabled.
  859. */
  860. static enum hrtimer_restart hrtick(struct hrtimer *timer)
  861. {
  862. struct rq *rq = container_of(timer, struct rq, hrtick_timer);
  863. WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
  864. raw_spin_lock(&rq->lock);
  865. update_rq_clock(rq);
  866. rq->curr->sched_class->task_tick(rq, rq->curr, 1);
  867. raw_spin_unlock(&rq->lock);
  868. return HRTIMER_NORESTART;
  869. }
  870. #ifdef CONFIG_SMP
  871. /*
  872. * called from hardirq (IPI) context
  873. */
  874. static void __hrtick_start(void *arg)
  875. {
  876. struct rq *rq = arg;
  877. raw_spin_lock(&rq->lock);
  878. hrtimer_restart(&rq->hrtick_timer);
  879. rq->hrtick_csd_pending = 0;
  880. raw_spin_unlock(&rq->lock);
  881. }
  882. /*
  883. * Called to set the hrtick timer state.
  884. *
  885. * called with rq->lock held and irqs disabled
  886. */
  887. static void hrtick_start(struct rq *rq, u64 delay)
  888. {
  889. struct hrtimer *timer = &rq->hrtick_timer;
  890. ktime_t time = ktime_add_ns(timer->base->get_time(), delay);
  891. hrtimer_set_expires(timer, time);
  892. if (rq == this_rq()) {
  893. hrtimer_restart(timer);
  894. } else if (!rq->hrtick_csd_pending) {
  895. __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd, 0);
  896. rq->hrtick_csd_pending = 1;
  897. }
  898. }
  899. static int
  900. hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu)
  901. {
  902. int cpu = (int)(long)hcpu;
  903. switch (action) {
  904. case CPU_UP_CANCELED:
  905. case CPU_UP_CANCELED_FROZEN:
  906. case CPU_DOWN_PREPARE:
  907. case CPU_DOWN_PREPARE_FROZEN:
  908. case CPU_DEAD:
  909. case CPU_DEAD_FROZEN:
  910. hrtick_clear(cpu_rq(cpu));
  911. return NOTIFY_OK;
  912. }
  913. return NOTIFY_DONE;
  914. }
  915. static __init void init_hrtick(void)
  916. {
  917. hotcpu_notifier(hotplug_hrtick, 0);
  918. }
  919. #else
  920. /*
  921. * Called to set the hrtick timer state.
  922. *
  923. * called with rq->lock held and irqs disabled
  924. */
  925. static void hrtick_start(struct rq *rq, u64 delay)
  926. {
  927. __hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0,
  928. HRTIMER_MODE_REL_PINNED, 0);
  929. }
  930. static inline void init_hrtick(void)
  931. {
  932. }
  933. #endif /* CONFIG_SMP */
  934. static void init_rq_hrtick(struct rq *rq)
  935. {
  936. #ifdef CONFIG_SMP
  937. rq->hrtick_csd_pending = 0;
  938. rq->hrtick_csd.flags = 0;
  939. rq->hrtick_csd.func = __hrtick_start;
  940. rq->hrtick_csd.info = rq;
  941. #endif
  942. hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
  943. rq->hrtick_timer.function = hrtick;
  944. }
  945. #else /* CONFIG_SCHED_HRTICK */
  946. static inline void hrtick_clear(struct rq *rq)
  947. {
  948. }
  949. static inline void init_rq_hrtick(struct rq *rq)
  950. {
  951. }
  952. static inline void init_hrtick(void)
  953. {
  954. }
  955. #endif /* CONFIG_SCHED_HRTICK */
  956. /*
  957. * resched_task - mark a task 'to be rescheduled now'.
  958. *
  959. * On UP this means the setting of the need_resched flag, on SMP it
  960. * might also involve a cross-CPU call to trigger the scheduler on
  961. * the target CPU.
  962. */
  963. #ifdef CONFIG_SMP
  964. #ifndef tsk_is_polling
  965. #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
  966. #endif
  967. static void resched_task(struct task_struct *p)
  968. {
  969. int cpu;
  970. assert_raw_spin_locked(&task_rq(p)->lock);
  971. if (test_tsk_need_resched(p))
  972. return;
  973. set_tsk_need_resched(p);
  974. cpu = task_cpu(p);
  975. if (cpu == smp_processor_id())
  976. return;
  977. /* NEED_RESCHED must be visible before we test polling */
  978. smp_mb();
  979. if (!tsk_is_polling(p))
  980. smp_send_reschedule(cpu);
  981. }
  982. static void resched_cpu(int cpu)
  983. {
  984. struct rq *rq = cpu_rq(cpu);
  985. unsigned long flags;
  986. if (!raw_spin_trylock_irqsave(&rq->lock, flags))
  987. return;
  988. resched_task(cpu_curr(cpu));
  989. raw_spin_unlock_irqrestore(&rq->lock, flags);
  990. }
  991. #ifdef CONFIG_NO_HZ
  992. /*
  993. * When add_timer_on() enqueues a timer into the timer wheel of an
  994. * idle CPU then this timer might expire before the next timer event
  995. * which is scheduled to wake up that CPU. In case of a completely
  996. * idle system the next event might even be infinite time into the
  997. * future. wake_up_idle_cpu() ensures that the CPU is woken up and
  998. * leaves the inner idle loop so the newly added timer is taken into
  999. * account when the CPU goes back to idle and evaluates the timer
  1000. * wheel for the next timer event.
  1001. */
  1002. void wake_up_idle_cpu(int cpu)
  1003. {
  1004. struct rq *rq = cpu_rq(cpu);
  1005. if (cpu == smp_processor_id())
  1006. return;
  1007. /*
  1008. * This is safe, as this function is called with the timer
  1009. * wheel base lock of (cpu) held. When the CPU is on the way
  1010. * to idle and has not yet set rq->curr to idle then it will
  1011. * be serialized on the timer wheel base lock and take the new
  1012. * timer into account automatically.
  1013. */
  1014. if (rq->curr != rq->idle)
  1015. return;
  1016. /*
  1017. * We can set TIF_RESCHED on the idle task of the other CPU
  1018. * lockless. The worst case is that the other CPU runs the
  1019. * idle task through an additional NOOP schedule()
  1020. */
  1021. set_tsk_need_resched(rq->idle);
  1022. /* NEED_RESCHED must be visible before we test polling */
  1023. smp_mb();
  1024. if (!tsk_is_polling(rq->idle))
  1025. smp_send_reschedule(cpu);
  1026. }
  1027. int nohz_ratelimit(int cpu)
  1028. {
  1029. struct rq *rq = cpu_rq(cpu);
  1030. u64 diff = rq->clock - rq->nohz_stamp;
  1031. rq->nohz_stamp = rq->clock;
  1032. return diff < (NSEC_PER_SEC / HZ) >> 1;
  1033. }
  1034. #endif /* CONFIG_NO_HZ */
  1035. static u64 sched_avg_period(void)
  1036. {
  1037. return (u64)sysctl_sched_time_avg * NSEC_PER_MSEC / 2;
  1038. }
  1039. static void sched_avg_update(struct rq *rq)
  1040. {
  1041. s64 period = sched_avg_period();
  1042. while ((s64)(rq->clock - rq->age_stamp) > period) {
  1043. rq->age_stamp += period;
  1044. rq->rt_avg /= 2;
  1045. }
  1046. }
  1047. static void sched_rt_avg_update(struct rq *rq, u64 rt_delta)
  1048. {
  1049. rq->rt_avg += rt_delta;
  1050. sched_avg_update(rq);
  1051. }
  1052. #else /* !CONFIG_SMP */
  1053. static void resched_task(struct task_struct *p)
  1054. {
  1055. assert_raw_spin_locked(&task_rq(p)->lock);
  1056. set_tsk_need_resched(p);
  1057. }
  1058. static void sched_rt_avg_update(struct rq *rq, u64 rt_delta)
  1059. {
  1060. }
  1061. #endif /* CONFIG_SMP */
  1062. #if BITS_PER_LONG == 32
  1063. # define WMULT_CONST (~0UL)
  1064. #else
  1065. # define WMULT_CONST (1UL << 32)
  1066. #endif
  1067. #define WMULT_SHIFT 32
  1068. /*
  1069. * Shift right and round:
  1070. */
  1071. #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
  1072. /*
  1073. * delta *= weight / lw
  1074. */
  1075. static unsigned long
  1076. calc_delta_mine(unsigned long delta_exec, unsigned long weight,
  1077. struct load_weight *lw)
  1078. {
  1079. u64 tmp;
  1080. if (!lw->inv_weight) {
  1081. if (BITS_PER_LONG > 32 && unlikely(lw->weight >= WMULT_CONST))
  1082. lw->inv_weight = 1;
  1083. else
  1084. lw->inv_weight = 1 + (WMULT_CONST-lw->weight/2)
  1085. / (lw->weight+1);
  1086. }
  1087. tmp = (u64)delta_exec * weight;
  1088. /*
  1089. * Check whether we'd overflow the 64-bit multiplication:
  1090. */
  1091. if (unlikely(tmp > WMULT_CONST))
  1092. tmp = SRR(SRR(tmp, WMULT_SHIFT/2) * lw->inv_weight,
  1093. WMULT_SHIFT/2);
  1094. else
  1095. tmp = SRR(tmp * lw->inv_weight, WMULT_SHIFT);
  1096. return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX);
  1097. }
  1098. static inline void update_load_add(struct load_weight *lw, unsigned long inc)
  1099. {
  1100. lw->weight += inc;
  1101. lw->inv_weight = 0;
  1102. }
  1103. static inline void update_load_sub(struct load_weight *lw, unsigned long dec)
  1104. {
  1105. lw->weight -= dec;
  1106. lw->inv_weight = 0;
  1107. }
  1108. /*
  1109. * To aid in avoiding the subversion of "niceness" due to uneven distribution
  1110. * of tasks with abnormal "nice" values across CPUs the contribution that
  1111. * each task makes to its run queue's load is weighted according to its
  1112. * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
  1113. * scaled version of the new time slice allocation that they receive on time
  1114. * slice expiry etc.
  1115. */
  1116. #define WEIGHT_IDLEPRIO 3
  1117. #define WMULT_IDLEPRIO 1431655765
  1118. /*
  1119. * Nice levels are multiplicative, with a gentle 10% change for every
  1120. * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
  1121. * nice 1, it will get ~10% less CPU time than another CPU-bound task
  1122. * that remained on nice 0.
  1123. *
  1124. * The "10% effect" is relative and cumulative: from _any_ nice level,
  1125. * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
  1126. * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
  1127. * If a task goes up by ~10% and another task goes down by ~10% then
  1128. * the relative distance between them is ~25%.)
  1129. */
  1130. static const int prio_to_weight[40] = {
  1131. /* -20 */ 88761, 71755, 56483, 46273, 36291,
  1132. /* -15 */ 29154, 23254, 18705, 14949, 11916,
  1133. /* -10 */ 9548, 7620, 6100, 4904, 3906,
  1134. /* -5 */ 3121, 2501, 1991, 1586, 1277,
  1135. /* 0 */ 1024, 820, 655, 526, 423,
  1136. /* 5 */ 335, 272, 215, 172, 137,
  1137. /* 10 */ 110, 87, 70, 56, 45,
  1138. /* 15 */ 36, 29, 23, 18, 15,
  1139. };
  1140. /*
  1141. * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
  1142. *
  1143. * In cases where the weight does not change often, we can use the
  1144. * precalculated inverse to speed up arithmetics by turning divisions
  1145. * into multiplications:
  1146. */
  1147. static const u32 prio_to_wmult[40] = {
  1148. /* -20 */ 48388, 59856, 76040, 92818, 118348,
  1149. /* -15 */ 147320, 184698, 229616, 287308, 360437,
  1150. /* -10 */ 449829, 563644, 704093, 875809, 1099582,
  1151. /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
  1152. /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
  1153. /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
  1154. /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
  1155. /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
  1156. };
  1157. /* Time spent by the tasks of the cpu accounting group executing in ... */
  1158. enum cpuacct_stat_index {
  1159. CPUACCT_STAT_USER, /* ... user mode */
  1160. CPUACCT_STAT_SYSTEM, /* ... kernel mode */
  1161. CPUACCT_STAT_NSTATS,
  1162. };
  1163. #ifdef CONFIG_CGROUP_CPUACCT
  1164. static void cpuacct_charge(struct task_struct *tsk, u64 cputime);
  1165. static void cpuacct_update_stats(struct task_struct *tsk,
  1166. enum cpuacct_stat_index idx, cputime_t val);
  1167. #else
  1168. static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}
  1169. static inline void cpuacct_update_stats(struct task_struct *tsk,
  1170. enum cpuacct_stat_index idx, cputime_t val) {}
  1171. #endif
  1172. static inline void inc_cpu_load(struct rq *rq, unsigned long load)
  1173. {
  1174. update_load_add(&rq->load, load);
  1175. }
  1176. static inline void dec_cpu_load(struct rq *rq, unsigned long load)
  1177. {
  1178. update_load_sub(&rq->load, load);
  1179. }
  1180. #if (defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)) || defined(CONFIG_RT_GROUP_SCHED)
  1181. typedef int (*tg_visitor)(struct task_group *, void *);
  1182. /*
  1183. * Iterate the full tree, calling @down when first entering a node and @up when
  1184. * leaving it for the final time.
  1185. */
  1186. static int walk_tg_tree(tg_visitor down, tg_visitor up, void *data)
  1187. {
  1188. struct task_group *parent, *child;
  1189. int ret;
  1190. rcu_read_lock();
  1191. parent = &root_task_group;
  1192. down:
  1193. ret = (*down)(parent, data);
  1194. if (ret)
  1195. goto out_unlock;
  1196. list_for_each_entry_rcu(child, &parent->children, siblings) {
  1197. parent = child;
  1198. goto down;
  1199. up:
  1200. continue;
  1201. }
  1202. ret = (*up)(parent, data);
  1203. if (ret)
  1204. goto out_unlock;
  1205. child = parent;
  1206. parent = parent->parent;
  1207. if (parent)
  1208. goto up;
  1209. out_unlock:
  1210. rcu_read_unlock();
  1211. return ret;
  1212. }
  1213. static int tg_nop(struct task_group *tg, void *data)
  1214. {
  1215. return 0;
  1216. }
  1217. #endif
  1218. #ifdef CONFIG_SMP
  1219. /* Used instead of source_load when we know the type == 0 */
  1220. static unsigned long weighted_cpuload(const int cpu)
  1221. {
  1222. return cpu_rq(cpu)->load.weight;
  1223. }
  1224. /*
  1225. * Return a low guess at the load of a migration-source cpu weighted
  1226. * according to the scheduling class and "nice" value.
  1227. *
  1228. * We want to under-estimate the load of migration sources, to
  1229. * balance conservatively.
  1230. */
  1231. static unsigned long source_load(int cpu, int type)
  1232. {
  1233. struct rq *rq = cpu_rq(cpu);
  1234. unsigned long total = weighted_cpuload(cpu);
  1235. if (type == 0 || !sched_feat(LB_BIAS))
  1236. return total;
  1237. return min(rq->cpu_load[type-1], total);
  1238. }
  1239. /*
  1240. * Return a high guess at the load of a migration-target cpu weighted
  1241. * according to the scheduling class and "nice" value.
  1242. */
  1243. static unsigned long target_load(int cpu, int type)
  1244. {
  1245. struct rq *rq = cpu_rq(cpu);
  1246. unsigned long total = weighted_cpuload(cpu);
  1247. if (type == 0 || !sched_feat(LB_BIAS))
  1248. return total;
  1249. return max(rq->cpu_load[type-1], total);
  1250. }
  1251. static struct sched_group *group_of(int cpu)
  1252. {
  1253. struct sched_domain *sd = rcu_dereference_sched(cpu_rq(cpu)->sd);
  1254. if (!sd)
  1255. return NULL;
  1256. return sd->groups;
  1257. }
  1258. static unsigned long power_of(int cpu)
  1259. {
  1260. struct sched_group *group = group_of(cpu);
  1261. if (!group)
  1262. return SCHED_LOAD_SCALE;
  1263. return group->cpu_power;
  1264. }
  1265. static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd);
  1266. static unsigned long cpu_avg_load_per_task(int cpu)
  1267. {
  1268. struct rq *rq = cpu_rq(cpu);
  1269. unsigned long nr_running = ACCESS_ONCE(rq->nr_running);
  1270. if (nr_running)
  1271. rq->avg_load_per_task = rq->load.weight / nr_running;
  1272. else
  1273. rq->avg_load_per_task = 0;
  1274. return rq->avg_load_per_task;
  1275. }
  1276. #ifdef CONFIG_FAIR_GROUP_SCHED
  1277. static __read_mostly unsigned long *update_shares_data;
  1278. static void __set_se_shares(struct sched_entity *se, unsigned long shares);
  1279. /*
  1280. * Calculate and set the cpu's group shares.
  1281. */
  1282. static void update_group_shares_cpu(struct task_group *tg, int cpu,
  1283. unsigned long sd_shares,
  1284. unsigned long sd_rq_weight,
  1285. unsigned long *usd_rq_weight)
  1286. {
  1287. unsigned long shares, rq_weight;
  1288. int boost = 0;
  1289. rq_weight = usd_rq_weight[cpu];
  1290. if (!rq_weight) {
  1291. boost = 1;
  1292. rq_weight = NICE_0_LOAD;
  1293. }
  1294. /*
  1295. * \Sum_j shares_j * rq_weight_i
  1296. * shares_i = -----------------------------
  1297. * \Sum_j rq_weight_j
  1298. */
  1299. shares = (sd_shares * rq_weight) / sd_rq_weight;
  1300. shares = clamp_t(unsigned long, shares, MIN_SHARES, MAX_SHARES);
  1301. if (abs(shares - tg->se[cpu]->load.weight) >
  1302. sysctl_sched_shares_thresh) {
  1303. struct rq *rq = cpu_rq(cpu);
  1304. unsigned long flags;
  1305. raw_spin_lock_irqsave(&rq->lock, flags);
  1306. tg->cfs_rq[cpu]->rq_weight = boost ? 0 : rq_weight;
  1307. tg->cfs_rq[cpu]->shares = boost ? 0 : shares;
  1308. __set_se_shares(tg->se[cpu], shares);
  1309. raw_spin_unlock_irqrestore(&rq->lock, flags);
  1310. }
  1311. }
  1312. /*
  1313. * Re-compute the task group their per cpu shares over the given domain.
  1314. * This needs to be done in a bottom-up fashion because the rq weight of a
  1315. * parent group depends on the shares of its child groups.
  1316. */
  1317. static int tg_shares_up(struct task_group *tg, void *data)
  1318. {
  1319. unsigned long weight, rq_weight = 0, sum_weight = 0, shares = 0;
  1320. unsigned long *usd_rq_weight;
  1321. struct sched_domain *sd = data;
  1322. unsigned long flags;
  1323. int i;
  1324. if (!tg->se[0])
  1325. return 0;
  1326. local_irq_save(flags);
  1327. usd_rq_weight = per_cpu_ptr(update_shares_data, smp_processor_id());
  1328. for_each_cpu(i, sched_domain_span(sd)) {
  1329. weight = tg->cfs_rq[i]->load.weight;
  1330. usd_rq_weight[i] = weight;
  1331. rq_weight += weight;
  1332. /*
  1333. * If there are currently no tasks on the cpu pretend there
  1334. * is one of average load so that when a new task gets to
  1335. * run here it will not get delayed by group starvation.
  1336. */
  1337. if (!weight)
  1338. weight = NICE_0_LOAD;
  1339. sum_weight += weight;
  1340. shares += tg->cfs_rq[i]->shares;
  1341. }
  1342. if (!rq_weight)
  1343. rq_weight = sum_weight;
  1344. if ((!shares && rq_weight) || shares > tg->shares)
  1345. shares = tg->shares;
  1346. if (!sd->parent || !(sd->parent->flags & SD_LOAD_BALANCE))
  1347. shares = tg->shares;
  1348. for_each_cpu(i, sched_domain_span(sd))
  1349. update_group_shares_cpu(tg, i, shares, rq_weight, usd_rq_weight);
  1350. local_irq_restore(flags);
  1351. return 0;
  1352. }
  1353. /*
  1354. * Compute the cpu's hierarchical load factor for each task group.
  1355. * This needs to be done in a top-down fashion because the load of a child
  1356. * group is a fraction of its parents load.
  1357. */
  1358. static int tg_load_down(struct task_group *tg, void *data)
  1359. {
  1360. unsigned long load;
  1361. long cpu = (long)data;
  1362. if (!tg->parent) {
  1363. load = cpu_rq(cpu)->load.weight;
  1364. } else {
  1365. load = tg->parent->cfs_rq[cpu]->h_load;
  1366. load *= tg->cfs_rq[cpu]->shares;
  1367. load /= tg->parent->cfs_rq[cpu]->load.weight + 1;
  1368. }
  1369. tg->cfs_rq[cpu]->h_load = load;
  1370. return 0;
  1371. }
  1372. static void update_shares(struct sched_domain *sd)
  1373. {
  1374. s64 elapsed;
  1375. u64 now;
  1376. if (root_task_group_empty())
  1377. return;
  1378. now = cpu_clock(raw_smp_processor_id());
  1379. elapsed = now - sd->last_update;
  1380. if (elapsed >= (s64)(u64)sysctl_sched_shares_ratelimit) {
  1381. sd->last_update = now;
  1382. walk_tg_tree(tg_nop, tg_shares_up, sd);
  1383. }
  1384. }
  1385. static void update_h_load(long cpu)
  1386. {
  1387. if (root_task_group_empty())
  1388. return;
  1389. walk_tg_tree(tg_load_down, tg_nop, (void *)cpu);
  1390. }
  1391. #else
  1392. static inline void update_shares(struct sched_domain *sd)
  1393. {
  1394. }
  1395. #endif
  1396. #ifdef CONFIG_PREEMPT
  1397. static void double_rq_lock(struct rq *rq1, struct rq *rq2);
  1398. /*
  1399. * fair double_lock_balance: Safely acquires both rq->locks in a fair
  1400. * way at the expense of forcing extra atomic operations in all
  1401. * invocations. This assures that the double_lock is acquired using the
  1402. * same underlying policy as the spinlock_t on this architecture, which
  1403. * reduces latency compared to the unfair variant below. However, it
  1404. * also adds more overhead and therefore may reduce throughput.
  1405. */
  1406. static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
  1407. __releases(this_rq->lock)
  1408. __acquires(busiest->lock)
  1409. __acquires(this_rq->lock)
  1410. {
  1411. raw_spin_unlock(&this_rq->lock);
  1412. double_rq_lock(this_rq, busiest);
  1413. return 1;
  1414. }
  1415. #else
  1416. /*
  1417. * Unfair double_lock_balance: Optimizes throughput at the expense of
  1418. * latency by eliminating extra atomic operations when the locks are
  1419. * already in proper order on entry. This favors lower cpu-ids and will
  1420. * grant the double lock to lower cpus over higher ids under contention,
  1421. * regardless of entry order into the function.
  1422. */
  1423. static int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
  1424. __releases(this_rq->lock)
  1425. __acquires(busiest->lock)
  1426. __acquires(this_rq->lock)
  1427. {
  1428. int ret = 0;
  1429. if (unlikely(!raw_spin_trylock(&busiest->lock))) {
  1430. if (busiest < this_rq) {
  1431. raw_spin_unlock(&this_rq->lock);
  1432. raw_spin_lock(&busiest->lock);
  1433. raw_spin_lock_nested(&this_rq->lock,
  1434. SINGLE_DEPTH_NESTING);
  1435. ret = 1;
  1436. } else
  1437. raw_spin_lock_nested(&busiest->lock,
  1438. SINGLE_DEPTH_NESTING);
  1439. }
  1440. return ret;
  1441. }
  1442. #endif /* CONFIG_PREEMPT */
  1443. /*
  1444. * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
  1445. */
  1446. static int double_lock_balance(struct rq *this_rq, struct rq *busiest)
  1447. {
  1448. if (unlikely(!irqs_disabled())) {
  1449. /* printk() doesn't work good under rq->lock */
  1450. raw_spin_unlock(&this_rq->lock);
  1451. BUG_ON(1);
  1452. }
  1453. return _double_lock_balance(this_rq, busiest);
  1454. }
  1455. static inline void double_unlock_balance(struct rq *this_rq, struct rq *busiest)
  1456. __releases(busiest->lock)
  1457. {
  1458. raw_spin_unlock(&busiest->lock);
  1459. lock_set_subclass(&this_rq->lock.dep_map, 0, _RET_IP_);
  1460. }
  1461. /*
  1462. * double_rq_lock - safely lock two runqueues
  1463. *
  1464. * Note this does not disable interrupts like task_rq_lock,
  1465. * you need to do so manually before calling.
  1466. */
  1467. static void double_rq_lock(struct rq *rq1, struct rq *rq2)
  1468. __acquires(rq1->lock)
  1469. __acquires(rq2->lock)
  1470. {
  1471. BUG_ON(!irqs_disabled());
  1472. if (rq1 == rq2) {
  1473. raw_spin_lock(&rq1->lock);
  1474. __acquire(rq2->lock); /* Fake it out ;) */
  1475. } else {
  1476. if (rq1 < rq2) {
  1477. raw_spin_lock(&rq1->lock);
  1478. raw_spin_lock_nested(&rq2->lock, SINGLE_DEPTH_NESTING);
  1479. } else {
  1480. raw_spin_lock(&rq2->lock);
  1481. raw_spin_lock_nested(&rq1->lock, SINGLE_DEPTH_NESTING);
  1482. }
  1483. }
  1484. update_rq_clock(rq1);
  1485. update_rq_clock(rq2);
  1486. }
  1487. /*
  1488. * double_rq_unlock - safely unlock two runqueues
  1489. *
  1490. * Note this does not restore interrupts like task_rq_unlock,
  1491. * you need to do so manually after calling.
  1492. */
  1493. static void double_rq_unlock(struct rq *rq1, struct rq *rq2)
  1494. __releases(rq1->lock)
  1495. __releases(rq2->lock)
  1496. {
  1497. raw_spin_unlock(&rq1->lock);
  1498. if (rq1 != rq2)
  1499. raw_spin_unlock(&rq2->lock);
  1500. else
  1501. __release(rq2->lock);
  1502. }
  1503. #endif
  1504. #ifdef CONFIG_FAIR_GROUP_SCHED
  1505. static void cfs_rq_set_shares(struct cfs_rq *cfs_rq, unsigned long shares)
  1506. {
  1507. #ifdef CONFIG_SMP
  1508. cfs_rq->shares = shares;
  1509. #endif
  1510. }
  1511. #endif
  1512. static void calc_load_account_active(struct rq *this_rq);
  1513. static void update_sysctl(void);
  1514. static int get_update_sysctl_factor(void);
  1515. static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
  1516. {
  1517. set_task_rq(p, cpu);
  1518. #ifdef CONFIG_SMP
  1519. /*
  1520. * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
  1521. * successfuly executed on another CPU. We must ensure that updates of
  1522. * per-task data have been completed by this moment.
  1523. */
  1524. smp_wmb();
  1525. task_thread_info(p)->cpu = cpu;
  1526. #endif
  1527. }
  1528. static const struct sched_class rt_sched_class;
  1529. #define sched_class_highest (&rt_sched_class)
  1530. #define for_each_class(class) \
  1531. for (class = sched_class_highest; class; class = class->next)
  1532. #include "sched_stats.h"
  1533. static void inc_nr_running(struct rq *rq)
  1534. {
  1535. rq->nr_running++;
  1536. }
  1537. static void dec_nr_running(struct rq *rq)
  1538. {
  1539. rq->nr_running--;
  1540. }
  1541. static void set_load_weight(struct task_struct *p)
  1542. {
  1543. if (task_has_rt_policy(p)) {
  1544. p->se.load.weight = prio_to_weight[0] * 2;
  1545. p->se.load.inv_weight = prio_to_wmult[0] >> 1;
  1546. return;
  1547. }
  1548. /*
  1549. * SCHED_IDLE tasks get minimal weight:
  1550. */
  1551. if (p->policy == SCHED_IDLE) {
  1552. p->se.load.weight = WEIGHT_IDLEPRIO;
  1553. p->se.load.inv_weight = WMULT_IDLEPRIO;
  1554. return;
  1555. }
  1556. p->se.load.weight = prio_to_weight[p->static_prio - MAX_RT_PRIO];
  1557. p->se.load.inv_weight = prio_to_wmult[p->static_prio - MAX_RT_PRIO];
  1558. }
  1559. static void update_avg(u64 *avg, u64 sample)
  1560. {
  1561. s64 diff = sample - *avg;
  1562. *avg += diff >> 3;
  1563. }
  1564. static void
  1565. enqueue_task(struct rq *rq, struct task_struct *p, int wakeup, bool head)
  1566. {
  1567. sched_info_queued(p);
  1568. p->sched_class->enqueue_task(rq, p, wakeup, head);
  1569. p->se.on_rq = 1;
  1570. }
  1571. static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep)
  1572. {
  1573. sched_info_dequeued(p);
  1574. p->sched_class->dequeue_task(rq, p, sleep);
  1575. p->se.on_rq = 0;
  1576. }
  1577. /*
  1578. * activate_task - move a task to the runqueue.
  1579. */
  1580. static void activate_task(struct rq *rq, struct task_struct *p, int wakeup)
  1581. {
  1582. if (task_contributes_to_load(p))
  1583. rq->nr_uninterruptible--;
  1584. enqueue_task(rq, p, wakeup, false);
  1585. inc_nr_running(rq);
  1586. }
  1587. /*
  1588. * deactivate_task - remove a task from the runqueue.
  1589. */
  1590. static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep)
  1591. {
  1592. if (task_contributes_to_load(p))
  1593. rq->nr_uninterruptible++;
  1594. dequeue_task(rq, p, sleep);
  1595. dec_nr_running(rq);
  1596. }
  1597. #include "sched_idletask.c"
  1598. #include "sched_fair.c"
  1599. #include "sched_rt.c"
  1600. #ifdef CONFIG_SCHED_DEBUG
  1601. # include "sched_debug.c"
  1602. #endif
  1603. /*
  1604. * __normal_prio - return the priority that is based on the static prio
  1605. */
  1606. static inline int __normal_prio(struct task_struct *p)
  1607. {
  1608. return p->static_prio;
  1609. }
  1610. /*
  1611. * Calculate the expected normal priority: i.e. priority
  1612. * without taking RT-inheritance into account. Might be
  1613. * boosted by interactivity modifiers. Changes upon fork,
  1614. * setprio syscalls, and whenever the interactivity
  1615. * estimator recalculates.
  1616. */
  1617. static inline int normal_prio(struct task_struct *p)
  1618. {
  1619. int prio;
  1620. if (task_has_rt_policy(p))
  1621. prio = MAX_RT_PRIO-1 - p->rt_priority;
  1622. else
  1623. prio = __normal_prio(p);
  1624. return prio;
  1625. }
  1626. /*
  1627. * Calculate the current priority, i.e. the priority
  1628. * taken into account by the scheduler. This value might
  1629. * be boosted by RT tasks, or might be boosted by
  1630. * interactivity modifiers. Will be RT if the task got
  1631. * RT-boosted. If not then it returns p->normal_prio.
  1632. */
  1633. static int effective_prio(struct task_struct *p)
  1634. {
  1635. p->normal_prio = normal_prio(p);
  1636. /*
  1637. * If we are RT tasks or we were boosted to RT priority,
  1638. * keep the priority unchanged. Otherwise, update priority
  1639. * to the normal priority:
  1640. */
  1641. if (!rt_prio(p->prio))
  1642. return p->normal_prio;
  1643. return p->prio;
  1644. }
  1645. /**
  1646. * task_curr - is this task currently executing on a CPU?
  1647. * @p: the task in question.
  1648. */
  1649. inline int task_curr(const struct task_struct *p)
  1650. {
  1651. return cpu_curr(task_cpu(p)) == p;
  1652. }
  1653. static inline void check_class_changed(struct rq *rq, struct task_struct *p,
  1654. const struct sched_class *prev_class,
  1655. int oldprio, int running)
  1656. {
  1657. if (prev_class != p->sched_class) {
  1658. if (prev_class->switched_from)
  1659. prev_class->switched_from(rq, p, running);
  1660. p->sched_class->switched_to(rq, p, running);
  1661. } else
  1662. p->sched_class->prio_changed(rq, p, oldprio, running);
  1663. }
  1664. #ifdef CONFIG_SMP
  1665. /*
  1666. * Is this task likely cache-hot:
  1667. */
  1668. static int
  1669. task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
  1670. {
  1671. s64 delta;
  1672. if (p->sched_class != &fair_sched_class)
  1673. return 0;
  1674. /*
  1675. * Buddy candidates are cache hot:
  1676. */
  1677. if (sched_feat(CACHE_HOT_BUDDY) && this_rq()->nr_running &&
  1678. (&p->se == cfs_rq_of(&p->se)->next ||
  1679. &p->se == cfs_rq_of(&p->se)->last))
  1680. return 1;
  1681. if (sysctl_sched_migration_cost == -1)
  1682. return 1;
  1683. if (sysctl_sched_migration_cost == 0)
  1684. return 0;
  1685. delta = now - p->se.exec_start;
  1686. return delta < (s64)sysctl_sched_migration_cost;
  1687. }
  1688. void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
  1689. {
  1690. #ifdef CONFIG_SCHED_DEBUG
  1691. /*
  1692. * We should never call set_task_cpu() on a blocked task,
  1693. * ttwu() will sort out the placement.
  1694. */
  1695. WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING &&
  1696. !(task_thread_info(p)->preempt_count & PREEMPT_ACTIVE));
  1697. #endif
  1698. trace_sched_migrate_task(p, new_cpu);
  1699. if (task_cpu(p) != new_cpu) {
  1700. p->se.nr_migrations++;
  1701. perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, 1, 1, NULL, 0);
  1702. }
  1703. __set_task_cpu(p, new_cpu);
  1704. }
  1705. struct migration_req {
  1706. struct list_head list;
  1707. struct task_struct *task;
  1708. int dest_cpu;
  1709. struct completion done;
  1710. };
  1711. /*
  1712. * The task's runqueue lock must be held.
  1713. * Returns true if you have to wait for migration thread.
  1714. */
  1715. static int
  1716. migrate_task(struct task_struct *p, int dest_cpu, struct migration_req *req)
  1717. {
  1718. struct rq *rq = task_rq(p);
  1719. /*
  1720. * If the task is not on a runqueue (and not running), then
  1721. * the next wake-up will properly place the task.
  1722. */
  1723. if (!p->se.on_rq && !task_running(rq, p))
  1724. return 0;
  1725. init_completion(&req->done);
  1726. req->task = p;
  1727. req->dest_cpu = dest_cpu;
  1728. list_add(&req->list, &rq->migration_queue);
  1729. return 1;
  1730. }
  1731. /*
  1732. * wait_task_context_switch - wait for a thread to complete at least one
  1733. * context switch.
  1734. *
  1735. * @p must not be current.
  1736. */
  1737. void wait_task_context_switch(struct task_struct *p)
  1738. {
  1739. unsigned long nvcsw, nivcsw, flags;
  1740. int running;
  1741. struct rq *rq;
  1742. nvcsw = p->nvcsw;
  1743. nivcsw = p->nivcsw;
  1744. for (;;) {
  1745. /*
  1746. * The runqueue is assigned before the actual context
  1747. * switch. We need to take the runqueue lock.
  1748. *
  1749. * We could check initially without the lock but it is
  1750. * very likely that we need to take the lock in every
  1751. * iteration.
  1752. */
  1753. rq = task_rq_lock(p, &flags);
  1754. running = task_running(rq, p);
  1755. task_rq_unlock(rq, &flags);
  1756. if (likely(!running))
  1757. break;
  1758. /*
  1759. * The switch count is incremented before the actual
  1760. * context switch. We thus wait for two switches to be
  1761. * sure at least one completed.
  1762. */
  1763. if ((p->nvcsw - nvcsw) > 1)
  1764. break;
  1765. if ((p->nivcsw - nivcsw) > 1)
  1766. break;
  1767. cpu_relax();
  1768. }
  1769. }
  1770. /*
  1771. * wait_task_inactive - wait for a thread to unschedule.
  1772. *
  1773. * If @match_state is nonzero, it's the @p->state value just checked and
  1774. * not expected to change. If it changes, i.e. @p might have woken up,
  1775. * then return zero. When we succeed in waiting for @p to be off its CPU,
  1776. * we return a positive number (its total switch count). If a second call
  1777. * a short while later returns the same number, the caller can be sure that
  1778. * @p has remained unscheduled the whole time.
  1779. *
  1780. * The caller must ensure that the task *will* unschedule sometime soon,
  1781. * else this function might spin for a *long* time. This function can't
  1782. * be called with interrupts off, or it may introduce deadlock with
  1783. * smp_call_function() if an IPI is sent by the same process we are
  1784. * waiting to become inactive.
  1785. */
  1786. unsigned long wait_task_inactive(struct task_struct *p, long match_state)
  1787. {
  1788. unsigned long flags;
  1789. int running, on_rq;
  1790. unsigned long ncsw;
  1791. struct rq *rq;
  1792. for (;;) {
  1793. /*
  1794. * We do the initial early heuristics without holding
  1795. * any task-queue locks at all. We'll only try to get
  1796. * the runqueue lock when things look like they will
  1797. * work out!
  1798. */
  1799. rq = task_rq(p);
  1800. /*
  1801. * If the task is actively running on another CPU
  1802. * still, just relax and busy-wait without holding
  1803. * any locks.
  1804. *
  1805. * NOTE! Since we don't hold any locks, it's not
  1806. * even sure that "rq" stays as the right runqueue!
  1807. * But we don't care, since "task_running()" will
  1808. * return false if the runqueue has changed and p
  1809. * is actually now running somewhere else!
  1810. */
  1811. while (task_running(rq, p)) {
  1812. if (match_state && unlikely(p->state != match_state))
  1813. return 0;
  1814. cpu_relax();
  1815. }
  1816. /*
  1817. * Ok, time to look more closely! We need the rq
  1818. * lock now, to be *sure*. If we're wrong, we'll
  1819. * just go back and repeat.
  1820. */
  1821. rq = task_rq_lock(p, &flags);
  1822. trace_sched_wait_task(rq, p);
  1823. running = task_running(rq, p);
  1824. on_rq = p->se.on_rq;
  1825. ncsw = 0;
  1826. if (!match_state || p->state == match_state)
  1827. ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
  1828. task_rq_unlock(rq, &flags);
  1829. /*
  1830. * If it changed from the expected state, bail out now.
  1831. */
  1832. if (unlikely(!ncsw))
  1833. break;
  1834. /*
  1835. * Was it really running after all now that we
  1836. * checked with the proper locks actually held?
  1837. *
  1838. * Oops. Go back and try again..
  1839. */
  1840. if (unlikely(running)) {
  1841. cpu_relax();
  1842. continue;
  1843. }
  1844. /*
  1845. * It's not enough that it's not actively running,
  1846. * it must be off the runqueue _entirely_, and not
  1847. * preempted!
  1848. *
  1849. * So if it was still runnable (but just not actively
  1850. * running right now), it's preempted, and we should
  1851. * yield - it could be a while.
  1852. */
  1853. if (unlikely(on_rq)) {
  1854. schedule_timeout_uninterruptible(1);
  1855. continue;
  1856. }
  1857. /*
  1858. * Ahh, all good. It wasn't running, and it wasn't
  1859. * runnable, which means that it will never become
  1860. * running in the future either. We're all done!
  1861. */
  1862. break;
  1863. }
  1864. return ncsw;
  1865. }
  1866. /***
  1867. * kick_process - kick a running thread to enter/exit the kernel
  1868. * @p: the to-be-kicked thread
  1869. *
  1870. * Cause a process which is running on another CPU to enter
  1871. * kernel-mode, without any delay. (to get signals handled.)
  1872. *
  1873. * NOTE: this function doesnt have to take the runqueue lock,
  1874. * because all it wants to ensure is that the remote task enters
  1875. * the kernel. If the IPI races and the task has been migrated
  1876. * to another CPU then no harm is done and the purpose has been
  1877. * achieved as well.
  1878. */
  1879. void kick_process(struct task_struct *p)
  1880. {
  1881. int cpu;
  1882. preempt_disable();
  1883. cpu = task_cpu(p);
  1884. if ((cpu != smp_processor_id()) && task_curr(p))
  1885. smp_send_reschedule(cpu);
  1886. preempt_enable();
  1887. }
  1888. EXPORT_SYMBOL_GPL(kick_process);
  1889. #endif /* CONFIG_SMP */
  1890. /**
  1891. * task_oncpu_function_call - call a function on the cpu on which a task runs
  1892. * @p: the task to evaluate
  1893. * @func: the function to be called
  1894. * @info: the function call argument
  1895. *
  1896. * Calls the function @func when the task is currently running. This might
  1897. * be on the current CPU, which just calls the function directly
  1898. */
  1899. void task_oncpu_function_call(struct task_struct *p,
  1900. void (*func) (void *info), void *info)
  1901. {
  1902. int cpu;
  1903. preempt_disable();
  1904. cpu = task_cpu(p);
  1905. if (task_curr(p))
  1906. smp_call_function_single(cpu, func, info, 1);
  1907. preempt_enable();
  1908. }
  1909. #ifdef CONFIG_SMP
  1910. static int select_fallback_rq(int cpu, struct task_struct *p)
  1911. {
  1912. int dest_cpu;
  1913. const struct cpumask *nodemask = cpumask_of_node(cpu_to_node(cpu));
  1914. /* Look for allowed, online CPU in same node. */
  1915. for_each_cpu_and(dest_cpu, nodemask, cpu_active_mask)
  1916. if (cpumask_test_cpu(dest_cpu, &p->cpus_allowed))
  1917. return dest_cpu;
  1918. /* Any allowed, online CPU? */
  1919. dest_cpu = cpumask_any_and(&p->cpus_allowed, cpu_active_mask);
  1920. if (dest_cpu < nr_cpu_ids)
  1921. return dest_cpu;
  1922. /* No more Mr. Nice Guy. */
  1923. if (dest_cpu >= nr_cpu_ids) {
  1924. rcu_read_lock();
  1925. cpuset_cpus_allowed_locked(p, &p->cpus_allowed);
  1926. rcu_read_unlock();
  1927. dest_cpu = cpumask_any_and(cpu_active_mask, &p->cpus_allowed);
  1928. /*
  1929. * Don't tell them about moving exiting tasks or
  1930. * kernel threads (both mm NULL), since they never
  1931. * leave kernel.
  1932. */
  1933. if (p->mm && printk_ratelimit()) {
  1934. printk(KERN_INFO "process %d (%s) no "
  1935. "longer affine to cpu%d\n",
  1936. task_pid_nr(p), p->comm, cpu);
  1937. }
  1938. }
  1939. return dest_cpu;
  1940. }
  1941. /*
  1942. * Gets called from 3 sites (exec, fork, wakeup), since it is called without
  1943. * holding rq->lock we need to ensure ->cpus_allowed is stable, this is done
  1944. * by:
  1945. *
  1946. * exec: is unstable, retry loop
  1947. * fork & wake-up: serialize ->cpus_allowed against TASK_WAKING
  1948. */
  1949. static inline
  1950. int select_task_rq(struct task_struct *p, int sd_flags, int wake_flags)
  1951. {
  1952. int cpu = p->sched_class->select_task_rq(p, sd_flags, wake_flags);
  1953. /*
  1954. * In order not to call set_task_cpu() on a blocking task we need
  1955. * to rely on ttwu() to place the task on a valid ->cpus_allowed
  1956. * cpu.
  1957. *
  1958. * Since this is common to all placement strategies, this lives here.
  1959. *
  1960. * [ this allows ->select_task() to simply return task_cpu(p) and
  1961. * not worry about this generic constraint ]
  1962. */
  1963. if (unlikely(!cpumask_test_cpu(cpu, &p->cpus_allowed) ||
  1964. !cpu_online(cpu)))
  1965. cpu = select_fallback_rq(task_cpu(p), p);
  1966. return cpu;
  1967. }
  1968. #endif
  1969. /***
  1970. * try_to_wake_up - wake up a thread
  1971. * @p: the to-be-woken-up thread
  1972. * @state: the mask of task states that can be woken
  1973. * @sync: do a synchronous wakeup?
  1974. *
  1975. * Put it on the run-queue if it's not already there. The "current"
  1976. * thread is always on the run-queue (except when the actual
  1977. * re-schedule is in progress), and as such you're allowed to do
  1978. * the simpler "current->state = TASK_RUNNING" to mark yourself
  1979. * runnable without the overhead of this.
  1980. *
  1981. * returns failure only if the task is already active.
  1982. */
  1983. static int try_to_wake_up(struct task_struct *p, unsigned int state,
  1984. int wake_flags)
  1985. {
  1986. int cpu, orig_cpu, this_cpu, success = 0;
  1987. unsigned long flags;
  1988. struct rq *rq;
  1989. if (!sched_feat(SYNC_WAKEUPS))
  1990. wake_flags &= ~WF_SYNC;
  1991. this_cpu = get_cpu();
  1992. smp_wmb();
  1993. rq = task_rq_lock(p, &flags);
  1994. update_rq_clock(rq);
  1995. if (!(p->state & state))
  1996. goto out;
  1997. if (p->se.on_rq)
  1998. goto out_running;
  1999. cpu = task_cpu(p);
  2000. orig_cpu = cpu;
  2001. #ifdef CONFIG_SMP
  2002. if (unlikely(task_running(rq, p)))
  2003. goto out_activate;
  2004. /*
  2005. * In order to handle concurrent wakeups and release the rq->lock
  2006. * we put the task in TASK_WAKING state.
  2007. *
  2008. * First fix up the nr_uninterruptible count:
  2009. */
  2010. if (task_contributes_to_load(p))
  2011. rq->nr_uninterruptible--;
  2012. p->state = TASK_WAKING;
  2013. if (p->sched_class->task_waking)
  2014. p->sched_class->task_waking(rq, p);
  2015. __task_rq_unlock(rq);
  2016. cpu = select_task_rq(p, SD_BALANCE_WAKE, wake_flags);
  2017. if (cpu != orig_cpu) {
  2018. /*
  2019. * Since we migrate the task without holding any rq->lock,
  2020. * we need to be careful with task_rq_lock(), since that
  2021. * might end up locking an invalid rq.
  2022. */
  2023. set_task_cpu(p, cpu);
  2024. }
  2025. rq = cpu_rq(cpu);
  2026. raw_spin_lock(&rq->lock);
  2027. update_rq_clock(rq);
  2028. /*
  2029. * We migrated the task without holding either rq->lock, however
  2030. * since the task is not on the task list itself, nobody else
  2031. * will try and migrate the task, hence the rq should match the
  2032. * cpu we just moved it to.
  2033. */
  2034. WARN_ON(task_cpu(p) != cpu);
  2035. WARN_ON(p->state != TASK_WAKING);
  2036. #ifdef CONFIG_SCHEDSTATS
  2037. schedstat_inc(rq, ttwu_count);
  2038. if (cpu == this_cpu)
  2039. schedstat_inc(rq, ttwu_local);
  2040. else {
  2041. struct sched_domain *sd;
  2042. for_each_domain(this_cpu, sd) {
  2043. if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
  2044. schedstat_inc(sd, ttwu_wake_remote);
  2045. break;
  2046. }
  2047. }
  2048. }
  2049. #endif /* CONFIG_SCHEDSTATS */
  2050. out_activate:
  2051. #endif /* CONFIG_SMP */
  2052. schedstat_inc(p, se.statistics.nr_wakeups);
  2053. if (wake_flags & WF_SYNC)
  2054. schedstat_inc(p, se.statistics.nr_wakeups_sync);
  2055. if (orig_cpu != cpu)
  2056. schedstat_inc(p, se.statistics.nr_wakeups_migrate);
  2057. if (cpu == this_cpu)
  2058. schedstat_inc(p, se.statistics.nr_wakeups_local);
  2059. else
  2060. schedstat_inc(p, se.statistics.nr_wakeups_remote);
  2061. activate_task(rq, p, 1);
  2062. success = 1;
  2063. out_running:
  2064. trace_sched_wakeup(rq, p, success);
  2065. check_preempt_curr(rq, p, wake_flags);
  2066. p->state = TASK_RUNNING;
  2067. #ifdef CONFIG_SMP
  2068. if (p->sched_class->task_woken)
  2069. p->sched_class->task_woken(rq, p);
  2070. if (unlikely(rq->idle_stamp)) {
  2071. u64 delta = rq->clock - rq->idle_stamp;
  2072. u64 max = 2*sysctl_sched_migration_cost;
  2073. if (delta > max)
  2074. rq->avg_idle = max;
  2075. else
  2076. update_avg(&rq->avg_idle, delta);
  2077. rq->idle_stamp = 0;
  2078. }
  2079. #endif
  2080. out:
  2081. task_rq_unlock(rq, &flags);
  2082. put_cpu();
  2083. return success;
  2084. }
  2085. /**
  2086. * wake_up_process - Wake up a specific process
  2087. * @p: The process to be woken up.
  2088. *
  2089. * Attempt to wake up the nominated process and move it to the set of runnable
  2090. * processes. Returns 1 if the process was woken up, 0 if it was already
  2091. * running.
  2092. *
  2093. * It may be assumed that this function implies a write memory barrier before
  2094. * changing the task state if and only if any tasks are woken up.
  2095. */
  2096. int wake_up_process(struct task_struct *p)
  2097. {
  2098. return try_to_wake_up(p, TASK_ALL, 0);
  2099. }
  2100. EXPORT_SYMBOL(wake_up_process);
  2101. int wake_up_state(struct task_struct *p, unsigned int state)
  2102. {
  2103. return try_to_wake_up(p, state, 0);
  2104. }
  2105. /*
  2106. * Perform scheduler related setup for a newly forked process p.
  2107. * p is forked by current.
  2108. *
  2109. * __sched_fork() is basic setup used by init_idle() too:
  2110. */
  2111. static void __sched_fork(struct task_struct *p)
  2112. {
  2113. p->se.exec_start = 0;
  2114. p->se.sum_exec_runtime = 0;
  2115. p->se.prev_sum_exec_runtime = 0;
  2116. p->se.nr_migrations = 0;
  2117. #ifdef CONFIG_SCHEDSTATS
  2118. memset(&p->se.statistics, 0, sizeof(p->se.statistics));
  2119. #endif
  2120. INIT_LIST_HEAD(&p->rt.run_list);
  2121. p->se.on_rq = 0;
  2122. INIT_LIST_HEAD(&p->se.group_node);
  2123. #ifdef CONFIG_PREEMPT_NOTIFIERS
  2124. INIT_HLIST_HEAD(&p->preempt_notifiers);
  2125. #endif
  2126. }
  2127. /*
  2128. * fork()/clone()-time setup:
  2129. */
  2130. void sched_fork(struct task_struct *p, int clone_flags)
  2131. {
  2132. int cpu = get_cpu();
  2133. __sched_fork(p);
  2134. /*
  2135. * We mark the process as waking here. This guarantees that
  2136. * nobody will actually run it, and a signal or other external
  2137. * event cannot wake it up and insert it on the runqueue either.
  2138. */
  2139. p->state = TASK_WAKING;
  2140. /*
  2141. * Revert to default priority/policy on fork if requested.
  2142. */
  2143. if (unlikely(p->sched_reset_on_fork)) {
  2144. if (p->policy == SCHED_FIFO || p->policy == SCHED_RR) {
  2145. p->policy = SCHED_NORMAL;
  2146. p->normal_prio = p->static_prio;
  2147. }
  2148. if (PRIO_TO_NICE(p->static_prio) < 0) {
  2149. p->static_prio = NICE_TO_PRIO(0);
  2150. p->normal_prio = p->static_prio;
  2151. set_load_weight(p);
  2152. }
  2153. /*
  2154. * We don't need the reset flag anymore after the fork. It has
  2155. * fulfilled its duty:
  2156. */
  2157. p->sched_reset_on_fork = 0;
  2158. }
  2159. /*
  2160. * Make sure we do not leak PI boosting priority to the child.
  2161. */
  2162. p->prio = current->normal_prio;
  2163. if (!rt_prio(p->prio))
  2164. p->sched_class = &fair_sched_class;
  2165. if (p->sched_class->task_fork)
  2166. p->sched_class->task_fork(p);
  2167. set_task_cpu(p, cpu);
  2168. #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
  2169. if (likely(sched_info_on()))
  2170. memset(&p->sched_info, 0, sizeof(p->sched_info));
  2171. #endif
  2172. #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
  2173. p->oncpu = 0;
  2174. #endif
  2175. #ifdef CONFIG_PREEMPT
  2176. /* Want to start with kernel preemption disabled. */
  2177. task_thread_info(p)->preempt_count = 1;
  2178. #endif
  2179. plist_node_init(&p->pushable_tasks, MAX_PRIO);
  2180. put_cpu();
  2181. }
  2182. /*
  2183. * wake_up_new_task - wake up a newly created task for the first time.
  2184. *
  2185. * This function will do some initial scheduler statistics housekeeping
  2186. * that must be done for every newly created context, then puts the task
  2187. * on the runqueue and wakes it.
  2188. */
  2189. void wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
  2190. {
  2191. unsigned long flags;
  2192. struct rq *rq;
  2193. int cpu = get_cpu();
  2194. #ifdef CONFIG_SMP
  2195. /*
  2196. * Fork balancing, do it here and not earlier because:
  2197. * - cpus_allowed can change in the fork path
  2198. * - any previously selected cpu might disappear through hotplug
  2199. *
  2200. * We still have TASK_WAKING but PF_STARTING is gone now, meaning
  2201. * ->cpus_allowed is stable, we have preemption disabled, meaning
  2202. * cpu_online_mask is stable.
  2203. */
  2204. cpu = select_task_rq(p, SD_BALANCE_FORK, 0);
  2205. set_task_cpu(p, cpu);
  2206. #endif
  2207. /*
  2208. * Since the task is not on the rq and we still have TASK_WAKING set
  2209. * nobody else will migrate this task.
  2210. */
  2211. rq = cpu_rq(cpu);
  2212. raw_spin_lock_irqsave(&rq->lock, flags);
  2213. BUG_ON(p->state != TASK_WAKING);
  2214. p->state = TASK_RUNNING;
  2215. update_rq_clock(rq);
  2216. activate_task(rq, p, 0);
  2217. trace_sched_wakeup_new(rq, p, 1);
  2218. check_preempt_curr(rq, p, WF_FORK);
  2219. #ifdef CONFIG_SMP
  2220. if (p->sched_class->task_woken)
  2221. p->sched_class->task_woken(rq, p);
  2222. #endif
  2223. task_rq_unlock(rq, &flags);
  2224. put_cpu();
  2225. }
  2226. #ifdef CONFIG_PREEMPT_NOTIFIERS
  2227. /**
  2228. * preempt_notifier_register - tell me when current is being preempted & rescheduled
  2229. * @notifier: notifier struct to register
  2230. */
  2231. void preempt_notifier_register(struct preempt_notifier *notifier)
  2232. {
  2233. hlist_add_head(&notifier->link, &current->preempt_notifiers);
  2234. }
  2235. EXPORT_SYMBOL_GPL(preempt_notifier_register);
  2236. /**
  2237. * preempt_notifier_unregister - no longer interested in preemption notifications
  2238. * @notifier: notifier struct to unregister
  2239. *
  2240. * This is safe to call from within a preemption notifier.
  2241. */
  2242. void preempt_notifier_unregister(struct preempt_notifier *notifier)
  2243. {
  2244. hlist_del(&notifier->link);
  2245. }
  2246. EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
  2247. static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
  2248. {
  2249. struct preempt_notifier *notifier;
  2250. struct hlist_node *node;
  2251. hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
  2252. notifier->ops->sched_in(notifier, raw_smp_processor_id());
  2253. }
  2254. static void
  2255. fire_sched_out_preempt_notifiers(struct task_struct *curr,
  2256. struct task_struct *next)
  2257. {
  2258. struct preempt_notifier *notifier;
  2259. struct hlist_node *node;
  2260. hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
  2261. notifier->ops->sched_out(notifier, next);
  2262. }
  2263. #else /* !CONFIG_PREEMPT_NOTIFIERS */
  2264. static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
  2265. {
  2266. }
  2267. static void
  2268. fire_sched_out_preempt_notifiers(struct task_struct *curr,
  2269. struct task_struct *next)
  2270. {
  2271. }
  2272. #endif /* CONFIG_PREEMPT_NOTIFIERS */
  2273. /**
  2274. * prepare_task_switch - prepare to switch tasks
  2275. * @rq: the runqueue preparing to switch
  2276. * @prev: the current task that is being switched out
  2277. * @next: the task we are going to switch to.
  2278. *
  2279. * This is called with the rq lock held and interrupts off. It must
  2280. * be paired with a subsequent finish_task_switch after the context
  2281. * switch.
  2282. *
  2283. * prepare_task_switch sets up locking and calls architecture specific
  2284. * hooks.
  2285. */
  2286. static inline void
  2287. prepare_task_switch(struct rq *rq, struct task_struct *prev,
  2288. struct task_struct *next)
  2289. {
  2290. fire_sched_out_preempt_notifiers(prev, next);
  2291. prepare_lock_switch(rq, next);
  2292. prepare_arch_switch(next);
  2293. }
  2294. /**
  2295. * finish_task_switch - clean up after a task-switch
  2296. * @rq: runqueue associated with task-switch
  2297. * @prev: the thread we just switched away from.
  2298. *
  2299. * finish_task_switch must be called after the context switch, paired
  2300. * with a prepare_task_switch call before the context switch.
  2301. * finish_task_switch will reconcile locking set up by prepare_task_switch,
  2302. * and do any other architecture-specific cleanup actions.
  2303. *
  2304. * Note that we may have delayed dropping an mm in context_switch(). If
  2305. * so, we finish that here outside of the runqueue lock. (Doing it
  2306. * with the lock held can cause deadlocks; see schedule() for
  2307. * details.)
  2308. */
  2309. static void finish_task_switch(struct rq *rq, struct task_struct *prev)
  2310. __releases(rq->lock)
  2311. {
  2312. struct mm_struct *mm = rq->prev_mm;
  2313. long prev_state;
  2314. rq->prev_mm = NULL;
  2315. /*
  2316. * A task struct has one reference for the use as "current".
  2317. * If a task dies, then it sets TASK_DEAD in tsk->state and calls
  2318. * schedule one last time. The schedule call will never return, and
  2319. * the scheduled task must drop that reference.
  2320. * The test for TASK_DEAD must occur while the runqueue locks are
  2321. * still held, otherwise prev could be scheduled on another cpu, die
  2322. * there before we look at prev->state, and then the reference would
  2323. * be dropped twice.
  2324. * Manfred Spraul <manfred@colorfullife.com>
  2325. */
  2326. prev_state = prev->state;
  2327. finish_arch_switch(prev);
  2328. #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
  2329. local_irq_disable();
  2330. #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
  2331. perf_event_task_sched_in(current);
  2332. #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
  2333. local_irq_enable();
  2334. #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
  2335. finish_lock_switch(rq, prev);
  2336. fire_sched_in_preempt_notifiers(current);
  2337. if (mm)
  2338. mmdrop(mm);
  2339. if (unlikely(prev_state == TASK_DEAD)) {
  2340. /*
  2341. * Remove function-return probe instances associated with this
  2342. * task and put them back on the free list.
  2343. */
  2344. kprobe_flush_task(prev);
  2345. put_task_struct(prev);
  2346. }
  2347. }
  2348. #ifdef CONFIG_SMP
  2349. /* assumes rq->lock is held */
  2350. static inline void pre_schedule(struct rq *rq, struct task_struct *prev)
  2351. {
  2352. if (prev->sched_class->pre_schedule)
  2353. prev->sched_class->pre_schedule(rq, prev);
  2354. }
  2355. /* rq->lock is NOT held, but preemption is disabled */
  2356. static inline void post_schedule(struct rq *rq)
  2357. {
  2358. if (rq->post_schedule) {
  2359. unsigned long flags;
  2360. raw_spin_lock_irqsave(&rq->lock, flags);
  2361. if (rq->curr->sched_class->post_schedule)
  2362. rq->curr->sched_class->post_schedule(rq);
  2363. raw_spin_unlock_irqrestore(&rq->lock, flags);
  2364. rq->post_schedule = 0;
  2365. }
  2366. }
  2367. #else
  2368. static inline void pre_schedule(struct rq *rq, struct task_struct *p)
  2369. {
  2370. }
  2371. static inline void post_schedule(struct rq *rq)
  2372. {
  2373. }
  2374. #endif
  2375. /**
  2376. * schedule_tail - first thing a freshly forked thread must call.
  2377. * @prev: the thread we just switched away from.
  2378. */
  2379. asmlinkage void schedule_tail(struct task_struct *prev)
  2380. __releases(rq->lock)
  2381. {
  2382. struct rq *rq = this_rq();
  2383. finish_task_switch(rq, prev);
  2384. /*
  2385. * FIXME: do we need to worry about rq being invalidated by the
  2386. * task_switch?
  2387. */
  2388. post_schedule(rq);
  2389. #ifdef __ARCH_WANT_UNLOCKED_CTXSW
  2390. /* In this case, finish_task_switch does not reenable preemption */
  2391. preempt_enable();
  2392. #endif
  2393. if (current->set_child_tid)
  2394. put_user(task_pid_vnr(current), current->set_child_tid);
  2395. }
  2396. /*
  2397. * context_switch - switch to the new MM and the new
  2398. * thread's register state.
  2399. */
  2400. static inline void
  2401. context_switch(struct rq *rq, struct task_struct *prev,
  2402. struct task_struct *next)
  2403. {
  2404. struct mm_struct *mm, *oldmm;
  2405. prepare_task_switch(rq, prev, next);
  2406. trace_sched_switch(rq, prev, next);
  2407. mm = next->mm;
  2408. oldmm = prev->active_mm;
  2409. /*
  2410. * For paravirt, this is coupled with an exit in switch_to to
  2411. * combine the page table reload and the switch backend into
  2412. * one hypercall.
  2413. */
  2414. arch_start_context_switch(prev);
  2415. if (likely(!mm)) {
  2416. next->active_mm = oldmm;
  2417. atomic_inc(&oldmm->mm_count);
  2418. enter_lazy_tlb(oldmm, next);
  2419. } else
  2420. switch_mm(oldmm, mm, next);
  2421. if (likely(!prev->mm)) {
  2422. prev->active_mm = NULL;
  2423. rq->prev_mm = oldmm;
  2424. }
  2425. /*
  2426. * Since the runqueue lock will be released by the next
  2427. * task (which is an invalid locking op but in the case
  2428. * of the scheduler it's an obvious special-case), so we
  2429. * do an early lockdep release here:
  2430. */
  2431. #ifndef __ARCH_WANT_UNLOCKED_CTXSW
  2432. spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
  2433. #endif
  2434. /* Here we just switch the register state and the stack. */
  2435. switch_to(prev, next, prev);
  2436. barrier();
  2437. /*
  2438. * this_rq must be evaluated again because prev may have moved
  2439. * CPUs since it called schedule(), thus the 'rq' on its stack
  2440. * frame will be invalid.
  2441. */
  2442. finish_task_switch(this_rq(), prev);
  2443. }
  2444. /*
  2445. * nr_running, nr_uninterruptible and nr_context_switches:
  2446. *
  2447. * externally visible scheduler statistics: current number of runnable
  2448. * threads, current number of uninterruptible-sleeping threads, total
  2449. * number of context switches performed since bootup.
  2450. */
  2451. unsigned long nr_running(void)
  2452. {
  2453. unsigned long i, sum = 0;
  2454. for_each_online_cpu(i)
  2455. sum += cpu_rq(i)->nr_running;
  2456. return sum;
  2457. }
  2458. unsigned long nr_uninterruptible(void)
  2459. {
  2460. unsigned long i, sum = 0;
  2461. for_each_possible_cpu(i)
  2462. sum += cpu_rq(i)->nr_uninterruptible;
  2463. /*
  2464. * Since we read the counters lockless, it might be slightly
  2465. * inaccurate. Do not allow it to go below zero though:
  2466. */
  2467. if (unlikely((long)sum < 0))
  2468. sum = 0;
  2469. return sum;
  2470. }
  2471. unsigned long long nr_context_switches(void)
  2472. {
  2473. int i;
  2474. unsigned long long sum = 0;
  2475. for_each_possible_cpu(i)
  2476. sum += cpu_rq(i)->nr_switches;
  2477. return sum;
  2478. }
  2479. unsigned long nr_iowait(void)
  2480. {
  2481. unsigned long i, sum = 0;
  2482. for_each_possible_cpu(i)
  2483. sum += atomic_read(&cpu_rq(i)->nr_iowait);
  2484. return sum;
  2485. }
  2486. unsigned long nr_iowait_cpu(void)
  2487. {
  2488. struct rq *this = this_rq();
  2489. return atomic_read(&this->nr_iowait);
  2490. }
  2491. unsigned long this_cpu_load(void)
  2492. {
  2493. struct rq *this = this_rq();
  2494. return this->cpu_load[0];
  2495. }
  2496. /* Variables and functions for calc_load */
  2497. static atomic_long_t calc_load_tasks;
  2498. static unsigned long calc_load_update;
  2499. unsigned long avenrun[3];
  2500. EXPORT_SYMBOL(avenrun);
  2501. /**
  2502. * get_avenrun - get the load average array
  2503. * @loads: pointer to dest load array
  2504. * @offset: offset to add
  2505. * @shift: shift count to shift the result left
  2506. *
  2507. * These values are estimates at best, so no need for locking.
  2508. */
  2509. void get_avenrun(unsigned long *loads, unsigned long offset, int shift)
  2510. {
  2511. loads[0] = (avenrun[0] + offset) << shift;
  2512. loads[1] = (avenrun[1] + offset) << shift;
  2513. loads[2] = (avenrun[2] + offset) << shift;
  2514. }
  2515. static unsigned long
  2516. calc_load(unsigned long load, unsigned long exp, unsigned long active)
  2517. {
  2518. load *= exp;
  2519. load += active * (FIXED_1 - exp);
  2520. return load >> FSHIFT;
  2521. }
  2522. /*
  2523. * calc_load - update the avenrun load estimates 10 ticks after the
  2524. * CPUs have updated calc_load_tasks.
  2525. */
  2526. void calc_global_load(void)
  2527. {
  2528. unsigned long upd = calc_load_update + 10;
  2529. long active;
  2530. if (time_before(jiffies, upd))
  2531. return;
  2532. active = atomic_long_read(&calc_load_tasks);
  2533. active = active > 0 ? active * FIXED_1 : 0;
  2534. avenrun[0] = calc_load(avenrun[0], EXP_1, active);
  2535. avenrun[1] = calc_load(avenrun[1], EXP_5, active);
  2536. avenrun[2] = calc_load(avenrun[2], EXP_15, active);
  2537. calc_load_update += LOAD_FREQ;
  2538. }
  2539. /*
  2540. * Either called from update_cpu_load() or from a cpu going idle
  2541. */
  2542. static void calc_load_account_active(struct rq *this_rq)
  2543. {
  2544. long nr_active, delta;
  2545. nr_active = this_rq->nr_running;
  2546. nr_active += (long) this_rq->nr_uninterruptible;
  2547. if (nr_active != this_rq->calc_load_active) {
  2548. delta = nr_active - this_rq->calc_load_active;
  2549. this_rq->calc_load_active = nr_active;
  2550. atomic_long_add(delta, &calc_load_tasks);
  2551. }
  2552. }
  2553. /*
  2554. * Update rq->cpu_load[] statistics. This function is usually called every
  2555. * scheduler tick (TICK_NSEC).
  2556. */
  2557. static void update_cpu_load(struct rq *this_rq)
  2558. {
  2559. unsigned long this_load = this_rq->load.weight;
  2560. int i, scale;
  2561. this_rq->nr_load_updates++;
  2562. /* Update our load: */
  2563. for (i = 0, scale = 1; i < CPU_LOAD_IDX_MAX; i++, scale += scale) {
  2564. unsigned long old_load, new_load;
  2565. /* scale is effectively 1 << i now, and >> i divides by scale */
  2566. old_load = this_rq->cpu_load[i];
  2567. new_load = this_load;
  2568. /*
  2569. * Round up the averaging division if load is increasing. This
  2570. * prevents us from getting stuck on 9 if the load is 10, for
  2571. * example.
  2572. */
  2573. if (new_load > old_load)
  2574. new_load += scale-1;
  2575. this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) >> i;
  2576. }
  2577. if (time_after_eq(jiffies, this_rq->calc_load_update)) {
  2578. this_rq->calc_load_update += LOAD_FREQ;
  2579. calc_load_account_active(this_rq);
  2580. }
  2581. }
  2582. #ifdef CONFIG_SMP
  2583. /*
  2584. * sched_exec - execve() is a valuable balancing opportunity, because at
  2585. * this point the task has the smallest effective memory and cache footprint.
  2586. */
  2587. void sched_exec(void)
  2588. {
  2589. struct task_struct *p = current;
  2590. struct migration_req req;
  2591. int dest_cpu, this_cpu;
  2592. unsigned long flags;
  2593. struct rq *rq;
  2594. again:
  2595. this_cpu = get_cpu();
  2596. dest_cpu = select_task_rq(p, SD_BALANCE_EXEC, 0);
  2597. if (dest_cpu == this_cpu) {
  2598. put_cpu();
  2599. return;
  2600. }
  2601. rq = task_rq_lock(p, &flags);
  2602. put_cpu();
  2603. /*
  2604. * select_task_rq() can race against ->cpus_allowed
  2605. */
  2606. if (!cpumask_test_cpu(dest_cpu, &p->cpus_allowed)
  2607. || unlikely(!cpu_active(dest_cpu))) {
  2608. task_rq_unlock(rq, &flags);
  2609. goto again;
  2610. }
  2611. /* force the process onto the specified CPU */
  2612. if (migrate_task(p, dest_cpu, &req)) {
  2613. /* Need to wait for migration thread (might exit: take ref). */
  2614. struct task_struct *mt = rq->migration_thread;
  2615. get_task_struct(mt);
  2616. task_rq_unlock(rq, &flags);
  2617. wake_up_process(mt);
  2618. put_task_struct(mt);
  2619. wait_for_completion(&req.done);
  2620. return;
  2621. }
  2622. task_rq_unlock(rq, &flags);
  2623. }
  2624. #endif
  2625. DEFINE_PER_CPU(struct kernel_stat, kstat);
  2626. EXPORT_PER_CPU_SYMBOL(kstat);
  2627. /*
  2628. * Return any ns on the sched_clock that have not yet been accounted in
  2629. * @p in case that task is currently running.
  2630. *
  2631. * Called with task_rq_lock() held on @rq.
  2632. */
  2633. static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq)
  2634. {
  2635. u64 ns = 0;
  2636. if (task_current(rq, p)) {
  2637. update_rq_clock(rq);
  2638. ns = rq->clock - p->se.exec_start;
  2639. if ((s64)ns < 0)
  2640. ns = 0;
  2641. }
  2642. return ns;
  2643. }
  2644. unsigned long long task_delta_exec(struct task_struct *p)
  2645. {
  2646. unsigned long flags;
  2647. struct rq *rq;
  2648. u64 ns = 0;
  2649. rq = task_rq_lock(p, &flags);
  2650. ns = do_task_delta_exec(p, rq);
  2651. task_rq_unlock(rq, &flags);
  2652. return ns;
  2653. }
  2654. /*
  2655. * Return accounted runtime for the task.
  2656. * In case the task is currently running, return the runtime plus current's
  2657. * pending runtime that have not been accounted yet.
  2658. */
  2659. unsigned long long task_sched_runtime(struct task_struct *p)
  2660. {
  2661. unsigned long flags;
  2662. struct rq *rq;
  2663. u64 ns = 0;
  2664. rq = task_rq_lock(p, &flags);
  2665. ns = p->se.sum_exec_runtime + do_task_delta_exec(p, rq);
  2666. task_rq_unlock(rq, &flags);
  2667. return ns;
  2668. }
  2669. /*
  2670. * Return sum_exec_runtime for the thread group.
  2671. * In case the task is currently running, return the sum plus current's
  2672. * pending runtime that have not been accounted yet.
  2673. *
  2674. * Note that the thread group might have other running tasks as well,
  2675. * so the return value not includes other pending runtime that other
  2676. * running tasks might have.
  2677. */
  2678. unsigned long long thread_group_sched_runtime(struct task_struct *p)
  2679. {
  2680. struct task_cputime totals;
  2681. unsigned long flags;
  2682. struct rq *rq;
  2683. u64 ns;
  2684. rq = task_rq_lock(p, &flags);
  2685. thread_group_cputime(p, &totals);
  2686. ns = totals.sum_exec_runtime + do_task_delta_exec(p, rq);
  2687. task_rq_unlock(rq, &flags);
  2688. return ns;
  2689. }
  2690. /*
  2691. * Account user cpu time to a process.
  2692. * @p: the process that the cpu time gets accounted to
  2693. * @cputime: the cpu time spent in user space since the last update
  2694. * @cputime_scaled: cputime scaled by cpu frequency
  2695. */
  2696. void account_user_time(struct task_struct *p, cputime_t cputime,
  2697. cputime_t cputime_scaled)
  2698. {
  2699. struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
  2700. cputime64_t tmp;
  2701. /* Add user time to process. */
  2702. p->utime = cputime_add(p->utime, cputime);
  2703. p->utimescaled = cputime_add(p->utimescaled, cputime_scaled);
  2704. account_group_user_time(p, cputime);
  2705. /* Add user time to cpustat. */
  2706. tmp = cputime_to_cputime64(cputime);
  2707. if (TASK_NICE(p) > 0)
  2708. cpustat->nice = cputime64_add(cpustat->nice, tmp);
  2709. else
  2710. cpustat->user = cputime64_add(cpustat->user, tmp);
  2711. cpuacct_update_stats(p, CPUACCT_STAT_USER, cputime);
  2712. /* Account for user time used */
  2713. acct_update_integrals(p);
  2714. }
  2715. /*
  2716. * Account guest cpu time to a process.
  2717. * @p: the process that the cpu time gets accounted to
  2718. * @cputime: the cpu time spent in virtual machine since the last update
  2719. * @cputime_scaled: cputime scaled by cpu frequency
  2720. */
  2721. static void account_guest_time(struct task_struct *p, cputime_t cputime,
  2722. cputime_t cputime_scaled)
  2723. {
  2724. cputime64_t tmp;
  2725. struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
  2726. tmp = cputime_to_cputime64(cputime);
  2727. /* Add guest time to process. */
  2728. p->utime = cputime_add(p->utime, cputime);
  2729. p->utimescaled = cputime_add(p->utimescaled, cputime_scaled);
  2730. account_group_user_time(p, cputime);
  2731. p->gtime = cputime_add(p->gtime, cputime);
  2732. /* Add guest time to cpustat. */
  2733. if (TASK_NICE(p) > 0) {
  2734. cpustat->nice = cputime64_add(cpustat->nice, tmp);
  2735. cpustat->guest_nice = cputime64_add(cpustat->guest_nice, tmp);
  2736. } else {
  2737. cpustat->user = cputime64_add(cpustat->user, tmp);
  2738. cpustat->guest = cputime64_add(cpustat->guest, tmp);
  2739. }
  2740. }
  2741. /*
  2742. * Account system cpu time to a process.
  2743. * @p: the process that the cpu time gets accounted to
  2744. * @hardirq_offset: the offset to subtract from hardirq_count()
  2745. * @cputime: the cpu time spent in kernel space since the last update
  2746. * @cputime_scaled: cputime scaled by cpu frequency
  2747. */
  2748. void account_system_time(struct task_struct *p, int hardirq_offset,
  2749. cputime_t cputime, cputime_t cputime_scaled)
  2750. {
  2751. struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
  2752. cputime64_t tmp;
  2753. if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
  2754. account_guest_time(p, cputime, cputime_scaled);
  2755. return;
  2756. }
  2757. /* Add system time to process. */
  2758. p->stime = cputime_add(p->stime, cputime);
  2759. p->stimescaled = cputime_add(p->stimescaled, cputime_scaled);
  2760. account_group_system_time(p, cputime);
  2761. /* Add system time to cpustat. */
  2762. tmp = cputime_to_cputime64(cputime);
  2763. if (hardirq_count() - hardirq_offset)
  2764. cpustat->irq = cputime64_add(cpustat->irq, tmp);
  2765. else if (softirq_count())
  2766. cpustat->softirq = cputime64_add(cpustat->softirq, tmp);
  2767. else
  2768. cpustat->system = cputime64_add(cpustat->system, tmp);
  2769. cpuacct_update_stats(p, CPUACCT_STAT_SYSTEM, cputime);
  2770. /* Account for system time used */
  2771. acct_update_integrals(p);
  2772. }
  2773. /*
  2774. * Account for involuntary wait time.
  2775. * @steal: the cpu time spent in involuntary wait
  2776. */
  2777. void account_steal_time(cputime_t cputime)
  2778. {
  2779. struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
  2780. cputime64_t cputime64 = cputime_to_cputime64(cputime);
  2781. cpustat->steal = cputime64_add(cpustat->steal, cputime64);
  2782. }
  2783. /*
  2784. * Account for idle time.
  2785. * @cputime: the cpu time spent in idle wait
  2786. */
  2787. void account_idle_time(cputime_t cputime)
  2788. {
  2789. struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
  2790. cputime64_t cputime64 = cputime_to_cputime64(cputime);
  2791. struct rq *rq = this_rq();
  2792. if (atomic_read(&rq->nr_iowait) > 0)
  2793. cpustat->iowait = cputime64_add(cpustat->iowait, cputime64);
  2794. else
  2795. cpustat->idle = cputime64_add(cpustat->idle, cputime64);
  2796. }
  2797. #ifndef CONFIG_VIRT_CPU_ACCOUNTING
  2798. /*
  2799. * Account a single tick of cpu time.
  2800. * @p: the process that the cpu time gets accounted to
  2801. * @user_tick: indicates if the tick is a user or a system tick
  2802. */
  2803. void account_process_tick(struct task_struct *p, int user_tick)
  2804. {
  2805. cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);
  2806. struct rq *rq = this_rq();
  2807. if (user_tick)
  2808. account_user_time(p, cputime_one_jiffy, one_jiffy_scaled);
  2809. else if ((p != rq->idle) || (irq_count() != HARDIRQ_OFFSET))
  2810. account_system_time(p, HARDIRQ_OFFSET, cputime_one_jiffy,
  2811. one_jiffy_scaled);
  2812. else
  2813. account_idle_time(cputime_one_jiffy);
  2814. }
  2815. /*
  2816. * Account multiple ticks of steal time.
  2817. * @p: the process from which the cpu time has been stolen
  2818. * @ticks: number of stolen ticks
  2819. */
  2820. void account_steal_ticks(unsigned long ticks)
  2821. {
  2822. account_steal_time(jiffies_to_cputime(ticks));
  2823. }
  2824. /*
  2825. * Account multiple ticks of idle time.
  2826. * @ticks: number of stolen ticks
  2827. */
  2828. void account_idle_ticks(unsigned long ticks)
  2829. {
  2830. account_idle_time(jiffies_to_cputime(ticks));
  2831. }
  2832. #endif
  2833. /*
  2834. * Use precise platform statistics if available:
  2835. */
  2836. #ifdef CONFIG_VIRT_CPU_ACCOUNTING
  2837. void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
  2838. {
  2839. *ut = p->utime;
  2840. *st = p->stime;
  2841. }
  2842. void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
  2843. {
  2844. struct task_cputime cputime;
  2845. thread_group_cputime(p, &cputime);
  2846. *ut = cputime.utime;
  2847. *st = cputime.stime;
  2848. }
  2849. #else
  2850. #ifndef nsecs_to_cputime
  2851. # define nsecs_to_cputime(__nsecs) nsecs_to_jiffies(__nsecs)
  2852. #endif
  2853. void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
  2854. {
  2855. cputime_t rtime, utime = p->utime, total = cputime_add(utime, p->stime);
  2856. /*
  2857. * Use CFS's precise accounting:
  2858. */
  2859. rtime = nsecs_to_cputime(p->se.sum_exec_runtime);
  2860. if (total) {
  2861. u64 temp;
  2862. temp = (u64)(rtime * utime);
  2863. do_div(temp, total);
  2864. utime = (cputime_t)temp;
  2865. } else
  2866. utime = rtime;
  2867. /*
  2868. * Compare with previous values, to keep monotonicity:
  2869. */
  2870. p->prev_utime = max(p->prev_utime, utime);
  2871. p->prev_stime = max(p->prev_stime, cputime_sub(rtime, p->prev_utime));
  2872. *ut = p->prev_utime;
  2873. *st = p->prev_stime;
  2874. }
  2875. /*
  2876. * Must be called with siglock held.
  2877. */
  2878. void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
  2879. {
  2880. struct signal_struct *sig = p->signal;
  2881. struct task_cputime cputime;
  2882. cputime_t rtime, utime, total;
  2883. thread_group_cputime(p, &cputime);
  2884. total = cputime_add(cputime.utime, cputime.stime);
  2885. rtime = nsecs_to_cputime(cputime.sum_exec_runtime);
  2886. if (total) {
  2887. u64 temp;
  2888. temp = (u64)(rtime * cputime.utime);
  2889. do_div(temp, total);
  2890. utime = (cputime_t)temp;
  2891. } else
  2892. utime = rtime;
  2893. sig->prev_utime = max(sig->prev_utime, utime);
  2894. sig->prev_stime = max(sig->prev_stime,
  2895. cputime_sub(rtime, sig->prev_utime));
  2896. *ut = sig->prev_utime;
  2897. *st = sig->prev_stime;
  2898. }
  2899. #endif
  2900. /*
  2901. * This function gets called by the timer code, with HZ frequency.
  2902. * We call it with interrupts disabled.
  2903. *
  2904. * It also gets called by the fork code, when changing the parent's
  2905. * timeslices.
  2906. */
  2907. void scheduler_tick(void)
  2908. {
  2909. int cpu = smp_processor_id();
  2910. struct rq *rq = cpu_rq(cpu);
  2911. struct task_struct *curr = rq->curr;
  2912. sched_clock_tick();
  2913. raw_spin_lock(&rq->lock);
  2914. update_rq_clock(rq);
  2915. update_cpu_load(rq);
  2916. curr->sched_class->task_tick(rq, curr, 0);
  2917. raw_spin_unlock(&rq->lock);
  2918. perf_event_task_tick(curr);
  2919. #ifdef CONFIG_SMP
  2920. rq->idle_at_tick = idle_cpu(cpu);
  2921. trigger_load_balance(rq, cpu);
  2922. #endif
  2923. }
  2924. notrace unsigned long get_parent_ip(unsigned long addr)
  2925. {
  2926. if (in_lock_functions(addr)) {
  2927. addr = CALLER_ADDR2;
  2928. if (in_lock_functions(addr))
  2929. addr = CALLER_ADDR3;
  2930. }
  2931. return addr;
  2932. }
  2933. #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
  2934. defined(CONFIG_PREEMPT_TRACER))
  2935. void __kprobes add_preempt_count(int val)
  2936. {
  2937. #ifdef CONFIG_DEBUG_PREEMPT
  2938. /*
  2939. * Underflow?
  2940. */
  2941. if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
  2942. return;
  2943. #endif
  2944. preempt_count() += val;
  2945. #ifdef CONFIG_DEBUG_PREEMPT
  2946. /*
  2947. * Spinlock count overflowing soon?
  2948. */
  2949. DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
  2950. PREEMPT_MASK - 10);
  2951. #endif
  2952. if (preempt_count() == val)
  2953. trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
  2954. }
  2955. EXPORT_SYMBOL(add_preempt_count);
  2956. void __kprobes sub_preempt_count(int val)
  2957. {
  2958. #ifdef CONFIG_DEBUG_PREEMPT
  2959. /*
  2960. * Underflow?
  2961. */
  2962. if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
  2963. return;
  2964. /*
  2965. * Is the spinlock portion underflowing?
  2966. */
  2967. if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
  2968. !(preempt_count() & PREEMPT_MASK)))
  2969. return;
  2970. #endif
  2971. if (preempt_count() == val)
  2972. trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
  2973. preempt_count() -= val;
  2974. }
  2975. EXPORT_SYMBOL(sub_preempt_count);
  2976. #endif
  2977. /*
  2978. * Print scheduling while atomic bug:
  2979. */
  2980. static noinline void __schedule_bug(struct task_struct *prev)
  2981. {
  2982. struct pt_regs *regs = get_irq_regs();
  2983. printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
  2984. prev->comm, prev->pid, preempt_count());
  2985. debug_show_held_locks(prev);
  2986. print_modules();
  2987. if (irqs_disabled())
  2988. print_irqtrace_events(prev);
  2989. if (regs)
  2990. show_regs(regs);
  2991. else
  2992. dump_stack();
  2993. }
  2994. /*
  2995. * Various schedule()-time debugging checks and statistics:
  2996. */
  2997. static inline void schedule_debug(struct task_struct *prev)
  2998. {
  2999. /*
  3000. * Test if we are atomic. Since do_exit() needs to call into
  3001. * schedule() atomically, we ignore that path for now.
  3002. * Otherwise, whine if we are scheduling when we should not be.
  3003. */
  3004. if (unlikely(in_atomic_preempt_off() && !prev->exit_state))
  3005. __schedule_bug(prev);
  3006. profile_hit(SCHED_PROFILING, __builtin_return_address(0));
  3007. schedstat_inc(this_rq(), sched_count);
  3008. #ifdef CONFIG_SCHEDSTATS
  3009. if (unlikely(prev->lock_depth >= 0)) {
  3010. schedstat_inc(this_rq(), bkl_count);
  3011. schedstat_inc(prev, sched_info.bkl_count);
  3012. }
  3013. #endif
  3014. }
  3015. static void put_prev_task(struct rq *rq, struct task_struct *prev)
  3016. {
  3017. prev->sched_class->put_prev_task(rq, prev);
  3018. }
  3019. /*
  3020. * Pick up the highest-prio task:
  3021. */
  3022. static inline struct task_struct *
  3023. pick_next_task(struct rq *rq)
  3024. {
  3025. const struct sched_class *class;
  3026. struct task_struct *p;
  3027. /*
  3028. * Optimization: we know that if all tasks are in
  3029. * the fair class we can call that function directly:
  3030. */
  3031. if (likely(rq->nr_running == rq->cfs.nr_running)) {
  3032. p = fair_sched_class.pick_next_task(rq);
  3033. if (likely(p))
  3034. return p;
  3035. }
  3036. class = sched_class_highest;
  3037. for ( ; ; ) {
  3038. p = class->pick_next_task(rq);
  3039. if (p)
  3040. return p;
  3041. /*
  3042. * Will never be NULL as the idle class always
  3043. * returns a non-NULL p:
  3044. */
  3045. class = class->next;
  3046. }
  3047. }
  3048. /*
  3049. * schedule() is the main scheduler function.
  3050. */
  3051. asmlinkage void __sched schedule(void)
  3052. {
  3053. struct task_struct *prev, *next;
  3054. unsigned long *switch_count;
  3055. struct rq *rq;
  3056. int cpu;
  3057. need_resched:
  3058. preempt_disable();
  3059. cpu = smp_processor_id();
  3060. rq = cpu_rq(cpu);
  3061. rcu_sched_qs(cpu);
  3062. prev = rq->curr;
  3063. switch_count = &prev->nivcsw;
  3064. release_kernel_lock(prev);
  3065. need_resched_nonpreemptible:
  3066. schedule_debug(prev);
  3067. if (sched_feat(HRTICK))
  3068. hrtick_clear(rq);
  3069. raw_spin_lock_irq(&rq->lock);
  3070. update_rq_clock(rq);
  3071. clear_tsk_need_resched(prev);
  3072. if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
  3073. if (unlikely(signal_pending_state(prev->state, prev)))
  3074. prev->state = TASK_RUNNING;
  3075. else
  3076. deactivate_task(rq, prev, 1);
  3077. switch_count = &prev->nvcsw;
  3078. }
  3079. pre_schedule(rq, prev);
  3080. if (unlikely(!rq->nr_running))
  3081. idle_balance(cpu, rq);
  3082. put_prev_task(rq, prev);
  3083. next = pick_next_task(rq);
  3084. if (likely(prev != next)) {
  3085. sched_info_switch(prev, next);
  3086. perf_event_task_sched_out(prev, next);
  3087. rq->nr_switches++;
  3088. rq->curr = next;
  3089. ++*switch_count;
  3090. context_switch(rq, prev, next); /* unlocks the rq */
  3091. /*
  3092. * the context switch might have flipped the stack from under
  3093. * us, hence refresh the local variables.
  3094. */
  3095. cpu = smp_processor_id();
  3096. rq = cpu_rq(cpu);
  3097. } else
  3098. raw_spin_unlock_irq(&rq->lock);
  3099. post_schedule(rq);
  3100. if (unlikely(reacquire_kernel_lock(current) < 0)) {
  3101. prev = rq->curr;
  3102. switch_count = &prev->nivcsw;
  3103. goto need_resched_nonpreemptible;
  3104. }
  3105. preempt_enable_no_resched();
  3106. if (need_resched())
  3107. goto need_resched;
  3108. }
  3109. EXPORT_SYMBOL(schedule);
  3110. #ifdef CONFIG_MUTEX_SPIN_ON_OWNER
  3111. /*
  3112. * Look out! "owner" is an entirely speculative pointer
  3113. * access and not reliable.
  3114. */
  3115. int mutex_spin_on_owner(struct mutex *lock, struct thread_info *owner)
  3116. {
  3117. unsigned int cpu;
  3118. struct rq *rq;
  3119. if (!sched_feat(OWNER_SPIN))
  3120. return 0;
  3121. #ifdef CONFIG_DEBUG_PAGEALLOC
  3122. /*
  3123. * Need to access the cpu field knowing that
  3124. * DEBUG_PAGEALLOC could have unmapped it if
  3125. * the mutex owner just released it and exited.
  3126. */
  3127. if (probe_kernel_address(&owner->cpu, cpu))
  3128. goto out;
  3129. #else
  3130. cpu = owner->cpu;
  3131. #endif
  3132. /*
  3133. * Even if the access succeeded (likely case),
  3134. * the cpu field may no longer be valid.
  3135. */
  3136. if (cpu >= nr_cpumask_bits)
  3137. goto out;
  3138. /*
  3139. * We need to validate that we can do a
  3140. * get_cpu() and that we have the percpu area.
  3141. */
  3142. if (!cpu_online(cpu))
  3143. goto out;
  3144. rq = cpu_rq(cpu);
  3145. for (;;) {
  3146. /*
  3147. * Owner changed, break to re-assess state.
  3148. */
  3149. if (lock->owner != owner)
  3150. break;
  3151. /*
  3152. * Is that owner really running on that cpu?
  3153. */
  3154. if (task_thread_info(rq->curr) != owner || need_resched())
  3155. return 0;
  3156. cpu_relax();
  3157. }
  3158. out:
  3159. return 1;
  3160. }
  3161. #endif
  3162. #ifdef CONFIG_PREEMPT
  3163. /*
  3164. * this is the entry point to schedule() from in-kernel preemption
  3165. * off of preempt_enable. Kernel preemptions off return from interrupt
  3166. * occur there and call schedule directly.
  3167. */
  3168. asmlinkage void __sched preempt_schedule(void)
  3169. {
  3170. struct thread_info *ti = current_thread_info();
  3171. /*
  3172. * If there is a non-zero preempt_count or interrupts are disabled,
  3173. * we do not want to preempt the current task. Just return..
  3174. */
  3175. if (likely(ti->preempt_count || irqs_disabled()))
  3176. return;
  3177. do {
  3178. add_preempt_count(PREEMPT_ACTIVE);
  3179. schedule();
  3180. sub_preempt_count(PREEMPT_ACTIVE);
  3181. /*
  3182. * Check again in case we missed a preemption opportunity
  3183. * between schedule and now.
  3184. */
  3185. barrier();
  3186. } while (need_resched());
  3187. }
  3188. EXPORT_SYMBOL(preempt_schedule);
  3189. /*
  3190. * this is the entry point to schedule() from kernel preemption
  3191. * off of irq context.
  3192. * Note, that this is called and return with irqs disabled. This will
  3193. * protect us against recursive calling from irq.
  3194. */
  3195. asmlinkage void __sched preempt_schedule_irq(void)
  3196. {
  3197. struct thread_info *ti = current_thread_info();
  3198. /* Catch callers which need to be fixed */
  3199. BUG_ON(ti->preempt_count || !irqs_disabled());
  3200. do {
  3201. add_preempt_count(PREEMPT_ACTIVE);
  3202. local_irq_enable();
  3203. schedule();
  3204. local_irq_disable();
  3205. sub_preempt_count(PREEMPT_ACTIVE);
  3206. /*
  3207. * Check again in case we missed a preemption opportunity
  3208. * between schedule and now.
  3209. */
  3210. barrier();
  3211. } while (need_resched());
  3212. }
  3213. #endif /* CONFIG_PREEMPT */
  3214. int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags,
  3215. void *key)
  3216. {
  3217. return try_to_wake_up(curr->private, mode, wake_flags);
  3218. }
  3219. EXPORT_SYMBOL(default_wake_function);
  3220. /*
  3221. * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
  3222. * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
  3223. * number) then we wake all the non-exclusive tasks and one exclusive task.
  3224. *
  3225. * There are circumstances in which we can try to wake a task which has already
  3226. * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
  3227. * zero in this (rare) case, and we handle it by continuing to scan the queue.
  3228. */
  3229. static void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
  3230. int nr_exclusive, int wake_flags, void *key)
  3231. {
  3232. wait_queue_t *curr, *next;
  3233. list_for_each_entry_safe(curr, next, &q->task_list, task_list) {
  3234. unsigned flags = curr->flags;
  3235. if (curr->func(curr, mode, wake_flags, key) &&
  3236. (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive)
  3237. break;
  3238. }
  3239. }
  3240. /**
  3241. * __wake_up - wake up threads blocked on a waitqueue.
  3242. * @q: the waitqueue
  3243. * @mode: which threads
  3244. * @nr_exclusive: how many wake-one or wake-many threads to wake up
  3245. * @key: is directly passed to the wakeup function
  3246. *
  3247. * It may be assumed that this function implies a write memory barrier before
  3248. * changing the task state if and only if any tasks are woken up.
  3249. */
  3250. void __wake_up(wait_queue_head_t *q, unsigned int mode,
  3251. int nr_exclusive, void *key)
  3252. {
  3253. unsigned long flags;
  3254. spin_lock_irqsave(&q->lock, flags);
  3255. __wake_up_common(q, mode, nr_exclusive, 0, key);
  3256. spin_unlock_irqrestore(&q->lock, flags);
  3257. }
  3258. EXPORT_SYMBOL(__wake_up);
  3259. /*
  3260. * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
  3261. */
  3262. void __wake_up_locked(wait_queue_head_t *q, unsigned int mode)
  3263. {
  3264. __wake_up_common(q, mode, 1, 0, NULL);
  3265. }
  3266. void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key)
  3267. {
  3268. __wake_up_common(q, mode, 1, 0, key);
  3269. }
  3270. /**
  3271. * __wake_up_sync_key - wake up threads blocked on a waitqueue.
  3272. * @q: the waitqueue
  3273. * @mode: which threads
  3274. * @nr_exclusive: how many wake-one or wake-many threads to wake up
  3275. * @key: opaque value to be passed to wakeup targets
  3276. *
  3277. * The sync wakeup differs that the waker knows that it will schedule
  3278. * away soon, so while the target thread will be woken up, it will not
  3279. * be migrated to another CPU - ie. the two threads are 'synchronized'
  3280. * with each other. This can prevent needless bouncing between CPUs.
  3281. *
  3282. * On UP it can prevent extra preemption.
  3283. *
  3284. * It may be assumed that this function implies a write memory barrier before
  3285. * changing the task state if and only if any tasks are woken up.
  3286. */
  3287. void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode,
  3288. int nr_exclusive, void *key)
  3289. {
  3290. unsigned long flags;
  3291. int wake_flags = WF_SYNC;
  3292. if (unlikely(!q))
  3293. return;
  3294. if (unlikely(!nr_exclusive))
  3295. wake_flags = 0;
  3296. spin_lock_irqsave(&q->lock, flags);
  3297. __wake_up_common(q, mode, nr_exclusive, wake_flags, key);
  3298. spin_unlock_irqrestore(&q->lock, flags);
  3299. }
  3300. EXPORT_SYMBOL_GPL(__wake_up_sync_key);
  3301. /*
  3302. * __wake_up_sync - see __wake_up_sync_key()
  3303. */
  3304. void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
  3305. {
  3306. __wake_up_sync_key(q, mode, nr_exclusive, NULL);
  3307. }
  3308. EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */
  3309. /**
  3310. * complete: - signals a single thread waiting on this completion
  3311. * @x: holds the state of this particular completion
  3312. *
  3313. * This will wake up a single thread waiting on this completion. Threads will be
  3314. * awakened in the same order in which they were queued.
  3315. *
  3316. * See also complete_all(), wait_for_completion() and related routines.
  3317. *
  3318. * It may be assumed that this function implies a write memory barrier before
  3319. * changing the task state if and only if any tasks are woken up.
  3320. */
  3321. void complete(struct completion *x)
  3322. {
  3323. unsigned long flags;
  3324. spin_lock_irqsave(&x->wait.lock, flags);
  3325. x->done++;
  3326. __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL);
  3327. spin_unlock_irqrestore(&x->wait.lock, flags);
  3328. }
  3329. EXPORT_SYMBOL(complete);
  3330. /**
  3331. * complete_all: - signals all threads waiting on this completion
  3332. * @x: holds the state of this particular completion
  3333. *
  3334. * This will wake up all threads waiting on this particular completion event.
  3335. *
  3336. * It may be assumed that this function implies a write memory barrier before
  3337. * changing the task state if and only if any tasks are woken up.
  3338. */
  3339. void complete_all(struct completion *x)
  3340. {
  3341. unsigned long flags;
  3342. spin_lock_irqsave(&x->wait.lock, flags);
  3343. x->done += UINT_MAX/2;
  3344. __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL);
  3345. spin_unlock_irqrestore(&x->wait.lock, flags);
  3346. }
  3347. EXPORT_SYMBOL(complete_all);
  3348. static inline long __sched
  3349. do_wait_for_common(struct completion *x, long timeout, int state)
  3350. {
  3351. if (!x->done) {
  3352. DECLARE_WAITQUEUE(wait, current);
  3353. wait.flags |= WQ_FLAG_EXCLUSIVE;
  3354. __add_wait_queue_tail(&x->wait, &wait);
  3355. do {
  3356. if (signal_pending_state(state, current)) {
  3357. timeout = -ERESTARTSYS;
  3358. break;
  3359. }
  3360. __set_current_state(state);
  3361. spin_unlock_irq(&x->wait.lock);
  3362. timeout = schedule_timeout(timeout);
  3363. spin_lock_irq(&x->wait.lock);
  3364. } while (!x->done && timeout);
  3365. __remove_wait_queue(&x->wait, &wait);
  3366. if (!x->done)
  3367. return timeout;
  3368. }
  3369. x->done--;
  3370. return timeout ?: 1;
  3371. }
  3372. static long __sched
  3373. wait_for_common(struct completion *x, long timeout, int state)
  3374. {
  3375. might_sleep();
  3376. spin_lock_irq(&x->wait.lock);
  3377. timeout = do_wait_for_common(x, timeout, state);
  3378. spin_unlock_irq(&x->wait.lock);
  3379. return timeout;
  3380. }
  3381. /**
  3382. * wait_for_completion: - waits for completion of a task
  3383. * @x: holds the state of this particular completion
  3384. *
  3385. * This waits to be signaled for completion of a specific task. It is NOT
  3386. * interruptible and there is no timeout.
  3387. *
  3388. * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
  3389. * and interrupt capability. Also see complete().
  3390. */
  3391. void __sched wait_for_completion(struct completion *x)
  3392. {
  3393. wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE);
  3394. }
  3395. EXPORT_SYMBOL(wait_for_completion);
  3396. /**
  3397. * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
  3398. * @x: holds the state of this particular completion
  3399. * @timeout: timeout value in jiffies
  3400. *
  3401. * This waits for either a completion of a specific task to be signaled or for a
  3402. * specified timeout to expire. The timeout is in jiffies. It is not
  3403. * interruptible.
  3404. */
  3405. unsigned long __sched
  3406. wait_for_completion_timeout(struct completion *x, unsigned long timeout)
  3407. {
  3408. return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE);
  3409. }
  3410. EXPORT_SYMBOL(wait_for_completion_timeout);
  3411. /**
  3412. * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
  3413. * @x: holds the state of this particular completion
  3414. *
  3415. * This waits for completion of a specific task to be signaled. It is
  3416. * interruptible.
  3417. */
  3418. int __sched wait_for_completion_interruptible(struct completion *x)
  3419. {
  3420. long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE);
  3421. if (t == -ERESTARTSYS)
  3422. return t;
  3423. return 0;
  3424. }
  3425. EXPORT_SYMBOL(wait_for_completion_interruptible);
  3426. /**
  3427. * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
  3428. * @x: holds the state of this particular completion
  3429. * @timeout: timeout value in jiffies
  3430. *
  3431. * This waits for either a completion of a specific task to be signaled or for a
  3432. * specified timeout to expire. It is interruptible. The timeout is in jiffies.
  3433. */
  3434. unsigned long __sched
  3435. wait_for_completion_interruptible_timeout(struct completion *x,
  3436. unsigned long timeout)
  3437. {
  3438. return wait_for_common(x, timeout, TASK_INTERRUPTIBLE);
  3439. }
  3440. EXPORT_SYMBOL(wait_for_completion_interruptible_timeout);
  3441. /**
  3442. * wait_for_completion_killable: - waits for completion of a task (killable)
  3443. * @x: holds the state of this particular completion
  3444. *
  3445. * This waits to be signaled for completion of a specific task. It can be
  3446. * interrupted by a kill signal.
  3447. */
  3448. int __sched wait_for_completion_killable(struct completion *x)
  3449. {
  3450. long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE);
  3451. if (t == -ERESTARTSYS)
  3452. return t;
  3453. return 0;
  3454. }
  3455. EXPORT_SYMBOL(wait_for_completion_killable);
  3456. /**
  3457. * try_wait_for_completion - try to decrement a completion without blocking
  3458. * @x: completion structure
  3459. *
  3460. * Returns: 0 if a decrement cannot be done without blocking
  3461. * 1 if a decrement succeeded.
  3462. *
  3463. * If a completion is being used as a counting completion,
  3464. * attempt to decrement the counter without blocking. This
  3465. * enables us to avoid waiting if the resource the completion
  3466. * is protecting is not available.
  3467. */
  3468. bool try_wait_for_completion(struct completion *x)
  3469. {
  3470. unsigned long flags;
  3471. int ret = 1;
  3472. spin_lock_irqsave(&x->wait.lock, flags);
  3473. if (!x->done)
  3474. ret = 0;
  3475. else
  3476. x->done--;
  3477. spin_unlock_irqrestore(&x->wait.lock, flags);
  3478. return ret;
  3479. }
  3480. EXPORT_SYMBOL(try_wait_for_completion);
  3481. /**
  3482. * completion_done - Test to see if a completion has any waiters
  3483. * @x: completion structure
  3484. *
  3485. * Returns: 0 if there are waiters (wait_for_completion() in progress)
  3486. * 1 if there are no waiters.
  3487. *
  3488. */
  3489. bool completion_done(struct completion *x)
  3490. {
  3491. unsigned long flags;
  3492. int ret = 1;
  3493. spin_lock_irqsave(&x->wait.lock, flags);
  3494. if (!x->done)
  3495. ret = 0;
  3496. spin_unlock_irqrestore(&x->wait.lock, flags);
  3497. return ret;
  3498. }
  3499. EXPORT_SYMBOL(completion_done);
  3500. static long __sched
  3501. sleep_on_common(wait_queue_head_t *q, int state, long timeout)
  3502. {
  3503. unsigned long flags;
  3504. wait_queue_t wait;
  3505. init_waitqueue_entry(&wait, current);
  3506. __set_current_state(state);
  3507. spin_lock_irqsave(&q->lock, flags);
  3508. __add_wait_queue(q, &wait);
  3509. spin_unlock(&q->lock);
  3510. timeout = schedule_timeout(timeout);
  3511. spin_lock_irq(&q->lock);
  3512. __remove_wait_queue(q, &wait);
  3513. spin_unlock_irqrestore(&q->lock, flags);
  3514. return timeout;
  3515. }
  3516. void __sched interruptible_sleep_on(wait_queue_head_t *q)
  3517. {
  3518. sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
  3519. }
  3520. EXPORT_SYMBOL(interruptible_sleep_on);
  3521. long __sched
  3522. interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout)
  3523. {
  3524. return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout);
  3525. }
  3526. EXPORT_SYMBOL(interruptible_sleep_on_timeout);
  3527. void __sched sleep_on(wait_queue_head_t *q)
  3528. {
  3529. sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
  3530. }
  3531. EXPORT_SYMBOL(sleep_on);
  3532. long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout)
  3533. {
  3534. return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout);
  3535. }
  3536. EXPORT_SYMBOL(sleep_on_timeout);
  3537. #ifdef CONFIG_RT_MUTEXES
  3538. /*
  3539. * rt_mutex_setprio - set the current priority of a task
  3540. * @p: task
  3541. * @prio: prio value (kernel-internal form)
  3542. *
  3543. * This function changes the 'effective' priority of a task. It does
  3544. * not touch ->normal_prio like __setscheduler().
  3545. *
  3546. * Used by the rt_mutex code to implement priority inheritance logic.
  3547. */
  3548. void rt_mutex_setprio(struct task_struct *p, int prio)
  3549. {
  3550. unsigned long flags;
  3551. int oldprio, on_rq, running;
  3552. struct rq *rq;
  3553. const struct sched_class *prev_class;
  3554. BUG_ON(prio < 0 || prio > MAX_PRIO);
  3555. rq = task_rq_lock(p, &flags);
  3556. update_rq_clock(rq);
  3557. oldprio = p->prio;
  3558. prev_class = p->sched_class;
  3559. on_rq = p->se.on_rq;
  3560. running = task_current(rq, p);
  3561. if (on_rq)
  3562. dequeue_task(rq, p, 0);
  3563. if (running)
  3564. p->sched_class->put_prev_task(rq, p);
  3565. if (rt_prio(prio))
  3566. p->sched_class = &rt_sched_class;
  3567. else
  3568. p->sched_class = &fair_sched_class;
  3569. p->prio = prio;
  3570. if (running)
  3571. p->sched_class->set_curr_task(rq);
  3572. if (on_rq) {
  3573. enqueue_task(rq, p, 0, oldprio < prio);
  3574. check_class_changed(rq, p, prev_class, oldprio, running);
  3575. }
  3576. task_rq_unlock(rq, &flags);
  3577. }
  3578. #endif
  3579. void set_user_nice(struct task_struct *p, long nice)
  3580. {
  3581. int old_prio, delta, on_rq;
  3582. unsigned long flags;
  3583. struct rq *rq;
  3584. if (TASK_NICE(p) == nice || nice < -20 || nice > 19)
  3585. return;
  3586. /*
  3587. * We have to be careful, if called from sys_setpriority(),
  3588. * the task might be in the middle of scheduling on another CPU.
  3589. */
  3590. rq = task_rq_lock(p, &flags);
  3591. update_rq_clock(rq);
  3592. /*
  3593. * The RT priorities are set via sched_setscheduler(), but we still
  3594. * allow the 'normal' nice value to be set - but as expected
  3595. * it wont have any effect on scheduling until the task is
  3596. * SCHED_FIFO/SCHED_RR:
  3597. */
  3598. if (task_has_rt_policy(p)) {
  3599. p->static_prio = NICE_TO_PRIO(nice);
  3600. goto out_unlock;
  3601. }
  3602. on_rq = p->se.on_rq;
  3603. if (on_rq)
  3604. dequeue_task(rq, p, 0);
  3605. p->static_prio = NICE_TO_PRIO(nice);
  3606. set_load_weight(p);
  3607. old_prio = p->prio;
  3608. p->prio = effective_prio(p);
  3609. delta = p->prio - old_prio;
  3610. if (on_rq) {
  3611. enqueue_task(rq, p, 0, false);
  3612. /*
  3613. * If the task increased its priority or is running and
  3614. * lowered its priority, then reschedule its CPU:
  3615. */
  3616. if (delta < 0 || (delta > 0 && task_running(rq, p)))
  3617. resched_task(rq->curr);
  3618. }
  3619. out_unlock:
  3620. task_rq_unlock(rq, &flags);
  3621. }
  3622. EXPORT_SYMBOL(set_user_nice);
  3623. /*
  3624. * can_nice - check if a task can reduce its nice value
  3625. * @p: task
  3626. * @nice: nice value
  3627. */
  3628. int can_nice(const struct task_struct *p, const int nice)
  3629. {
  3630. /* convert nice value [19,-20] to rlimit style value [1,40] */
  3631. int nice_rlim = 20 - nice;
  3632. return (nice_rlim <= p->signal->rlim[RLIMIT_NICE].rlim_cur ||
  3633. capable(CAP_SYS_NICE));
  3634. }
  3635. #ifdef __ARCH_WANT_SYS_NICE
  3636. /*
  3637. * sys_nice - change the priority of the current process.
  3638. * @increment: priority increment
  3639. *
  3640. * sys_setpriority is a more generic, but much slower function that
  3641. * does similar things.
  3642. */
  3643. SYSCALL_DEFINE1(nice, int, increment)
  3644. {
  3645. long nice, retval;
  3646. /*
  3647. * Setpriority might change our priority at the same moment.
  3648. * We don't have to worry. Conceptually one call occurs first
  3649. * and we have a single winner.
  3650. */
  3651. if (increment < -40)
  3652. increment = -40;
  3653. if (increment > 40)
  3654. increment = 40;
  3655. nice = TASK_NICE(current) + increment;
  3656. if (nice < -20)
  3657. nice = -20;
  3658. if (nice > 19)
  3659. nice = 19;
  3660. if (increment < 0 && !can_nice(current, nice))
  3661. return -EPERM;
  3662. retval = security_task_setnice(current, nice);
  3663. if (retval)
  3664. return retval;
  3665. set_user_nice(current, nice);
  3666. return 0;
  3667. }
  3668. #endif
  3669. /**
  3670. * task_prio - return the priority value of a given task.
  3671. * @p: the task in question.
  3672. *
  3673. * This is the priority value as seen by users in /proc.
  3674. * RT tasks are offset by -200. Normal tasks are centered
  3675. * around 0, value goes from -16 to +15.
  3676. */
  3677. int task_prio(const struct task_struct *p)
  3678. {
  3679. return p->prio - MAX_RT_PRIO;
  3680. }
  3681. /**
  3682. * task_nice - return the nice value of a given task.
  3683. * @p: the task in question.
  3684. */
  3685. int task_nice(const struct task_struct *p)
  3686. {
  3687. return TASK_NICE(p);
  3688. }
  3689. EXPORT_SYMBOL(task_nice);
  3690. /**
  3691. * idle_cpu - is a given cpu idle currently?
  3692. * @cpu: the processor in question.
  3693. */
  3694. int idle_cpu(int cpu)
  3695. {
  3696. return cpu_curr(cpu) == cpu_rq(cpu)->idle;
  3697. }
  3698. /**
  3699. * idle_task - return the idle task for a given cpu.
  3700. * @cpu: the processor in question.
  3701. */
  3702. struct task_struct *idle_task(int cpu)
  3703. {
  3704. return cpu_rq(cpu)->idle;
  3705. }
  3706. /**
  3707. * find_process_by_pid - find a process with a matching PID value.
  3708. * @pid: the pid in question.
  3709. */
  3710. static struct task_struct *find_process_by_pid(pid_t pid)
  3711. {
  3712. return pid ? find_task_by_vpid(pid) : current;
  3713. }
  3714. /* Actually do priority change: must hold rq lock. */
  3715. static void
  3716. __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio)
  3717. {
  3718. BUG_ON(p->se.on_rq);
  3719. p->policy = policy;
  3720. p->rt_priority = prio;
  3721. p->normal_prio = normal_prio(p);
  3722. /* we are holding p->pi_lock already */
  3723. p->prio = rt_mutex_getprio(p);
  3724. if (rt_prio(p->prio))
  3725. p->sched_class = &rt_sched_class;
  3726. else
  3727. p->sched_class = &fair_sched_class;
  3728. set_load_weight(p);
  3729. }
  3730. /*
  3731. * check the target process has a UID that matches the current process's
  3732. */
  3733. static bool check_same_owner(struct task_struct *p)
  3734. {
  3735. const struct cred *cred = current_cred(), *pcred;
  3736. bool match;
  3737. rcu_read_lock();
  3738. pcred = __task_cred(p);
  3739. match = (cred->euid == pcred->euid ||
  3740. cred->euid == pcred->uid);
  3741. rcu_read_unlock();
  3742. return match;
  3743. }
  3744. static int __sched_setscheduler(struct task_struct *p, int policy,
  3745. struct sched_param *param, bool user)
  3746. {
  3747. int retval, oldprio, oldpolicy = -1, on_rq, running;
  3748. unsigned long flags;
  3749. const struct sched_class *prev_class;
  3750. struct rq *rq;
  3751. int reset_on_fork;
  3752. /* may grab non-irq protected spin_locks */
  3753. BUG_ON(in_interrupt());
  3754. recheck:
  3755. /* double check policy once rq lock held */
  3756. if (policy < 0) {
  3757. reset_on_fork = p->sched_reset_on_fork;
  3758. policy = oldpolicy = p->policy;
  3759. } else {
  3760. reset_on_fork = !!(policy & SCHED_RESET_ON_FORK);
  3761. policy &= ~SCHED_RESET_ON_FORK;
  3762. if (policy != SCHED_FIFO && policy != SCHED_RR &&
  3763. policy != SCHED_NORMAL && policy != SCHED_BATCH &&
  3764. policy != SCHED_IDLE)
  3765. return -EINVAL;
  3766. }
  3767. /*
  3768. * Valid priorities for SCHED_FIFO and SCHED_RR are
  3769. * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
  3770. * SCHED_BATCH and SCHED_IDLE is 0.
  3771. */
  3772. if (param->sched_priority < 0 ||
  3773. (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) ||
  3774. (!p->mm && param->sched_priority > MAX_RT_PRIO-1))
  3775. return -EINVAL;
  3776. if (rt_policy(policy) != (param->sched_priority != 0))
  3777. return -EINVAL;
  3778. /*
  3779. * Allow unprivileged RT tasks to decrease priority:
  3780. */
  3781. if (user && !capable(CAP_SYS_NICE)) {
  3782. if (rt_policy(policy)) {
  3783. unsigned long rlim_rtprio;
  3784. if (!lock_task_sighand(p, &flags))
  3785. return -ESRCH;
  3786. rlim_rtprio = p->signal->rlim[RLIMIT_RTPRIO].rlim_cur;
  3787. unlock_task_sighand(p, &flags);
  3788. /* can't set/change the rt policy */
  3789. if (policy != p->policy && !rlim_rtprio)
  3790. return -EPERM;
  3791. /* can't increase priority */
  3792. if (param->sched_priority > p->rt_priority &&
  3793. param->sched_priority > rlim_rtprio)
  3794. return -EPERM;
  3795. }
  3796. /*
  3797. * Like positive nice levels, dont allow tasks to
  3798. * move out of SCHED_IDLE either:
  3799. */
  3800. if (p->policy == SCHED_IDLE && policy != SCHED_IDLE)
  3801. return -EPERM;
  3802. /* can't change other user's priorities */
  3803. if (!check_same_owner(p))
  3804. return -EPERM;
  3805. /* Normal users shall not reset the sched_reset_on_fork flag */
  3806. if (p->sched_reset_on_fork && !reset_on_fork)
  3807. return -EPERM;
  3808. }
  3809. if (user) {
  3810. #ifdef CONFIG_RT_GROUP_SCHED
  3811. /*
  3812. * Do not allow realtime tasks into groups that have no runtime
  3813. * assigned.
  3814. */
  3815. if (rt_bandwidth_enabled() && rt_policy(policy) &&
  3816. task_group(p)->rt_bandwidth.rt_runtime == 0)
  3817. return -EPERM;
  3818. #endif
  3819. retval = security_task_setscheduler(p, policy, param);
  3820. if (retval)
  3821. return retval;
  3822. }
  3823. /*
  3824. * make sure no PI-waiters arrive (or leave) while we are
  3825. * changing the priority of the task:
  3826. */
  3827. raw_spin_lock_irqsave(&p->pi_lock, flags);
  3828. /*
  3829. * To be able to change p->policy safely, the apropriate
  3830. * runqueue lock must be held.
  3831. */
  3832. rq = __task_rq_lock(p);
  3833. /* recheck policy now with rq lock held */
  3834. if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
  3835. policy = oldpolicy = -1;
  3836. __task_rq_unlock(rq);
  3837. raw_spin_unlock_irqrestore(&p->pi_lock, flags);
  3838. goto recheck;
  3839. }
  3840. update_rq_clock(rq);
  3841. on_rq = p->se.on_rq;
  3842. running = task_current(rq, p);
  3843. if (on_rq)
  3844. deactivate_task(rq, p, 0);
  3845. if (running)
  3846. p->sched_class->put_prev_task(rq, p);
  3847. p->sched_reset_on_fork = reset_on_fork;
  3848. oldprio = p->prio;
  3849. prev_class = p->sched_class;
  3850. __setscheduler(rq, p, policy, param->sched_priority);
  3851. if (running)
  3852. p->sched_class->set_curr_task(rq);
  3853. if (on_rq) {
  3854. activate_task(rq, p, 0);
  3855. check_class_changed(rq, p, prev_class, oldprio, running);
  3856. }
  3857. __task_rq_unlock(rq);
  3858. raw_spin_unlock_irqrestore(&p->pi_lock, flags);
  3859. rt_mutex_adjust_pi(p);
  3860. return 0;
  3861. }
  3862. /**
  3863. * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
  3864. * @p: the task in question.
  3865. * @policy: new policy.
  3866. * @param: structure containing the new RT priority.
  3867. *
  3868. * NOTE that the task may be already dead.
  3869. */
  3870. int sched_setscheduler(struct task_struct *p, int policy,
  3871. struct sched_param *param)
  3872. {
  3873. return __sched_setscheduler(p, policy, param, true);
  3874. }
  3875. EXPORT_SYMBOL_GPL(sched_setscheduler);
  3876. /**
  3877. * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
  3878. * @p: the task in question.
  3879. * @policy: new policy.
  3880. * @param: structure containing the new RT priority.
  3881. *
  3882. * Just like sched_setscheduler, only don't bother checking if the
  3883. * current context has permission. For example, this is needed in
  3884. * stop_machine(): we create temporary high priority worker threads,
  3885. * but our caller might not have that capability.
  3886. */
  3887. int sched_setscheduler_nocheck(struct task_struct *p, int policy,
  3888. struct sched_param *param)
  3889. {
  3890. return __sched_setscheduler(p, policy, param, false);
  3891. }
  3892. static int
  3893. do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
  3894. {
  3895. struct sched_param lparam;
  3896. struct task_struct *p;
  3897. int retval;
  3898. if (!param || pid < 0)
  3899. return -EINVAL;
  3900. if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
  3901. return -EFAULT;
  3902. rcu_read_lock();
  3903. retval = -ESRCH;
  3904. p = find_process_by_pid(pid);
  3905. if (p != NULL)
  3906. retval = sched_setscheduler(p, policy, &lparam);
  3907. rcu_read_unlock();
  3908. return retval;
  3909. }
  3910. /**
  3911. * sys_sched_setscheduler - set/change the scheduler policy and RT priority
  3912. * @pid: the pid in question.
  3913. * @policy: new policy.
  3914. * @param: structure containing the new RT priority.
  3915. */
  3916. SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy,
  3917. struct sched_param __user *, param)
  3918. {
  3919. /* negative values for policy are not valid */
  3920. if (policy < 0)
  3921. return -EINVAL;
  3922. return do_sched_setscheduler(pid, policy, param);
  3923. }
  3924. /**
  3925. * sys_sched_setparam - set/change the RT priority of a thread
  3926. * @pid: the pid in question.
  3927. * @param: structure containing the new RT priority.
  3928. */
  3929. SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param)
  3930. {
  3931. return do_sched_setscheduler(pid, -1, param);
  3932. }
  3933. /**
  3934. * sys_sched_getscheduler - get the policy (scheduling class) of a thread
  3935. * @pid: the pid in question.
  3936. */
  3937. SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid)
  3938. {
  3939. struct task_struct *p;
  3940. int retval;
  3941. if (pid < 0)
  3942. return -EINVAL;
  3943. retval = -ESRCH;
  3944. rcu_read_lock();
  3945. p = find_process_by_pid(pid);
  3946. if (p) {
  3947. retval = security_task_getscheduler(p);
  3948. if (!retval)
  3949. retval = p->policy
  3950. | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0);
  3951. }
  3952. rcu_read_unlock();
  3953. return retval;
  3954. }
  3955. /**
  3956. * sys_sched_getparam - get the RT priority of a thread
  3957. * @pid: the pid in question.
  3958. * @param: structure containing the RT priority.
  3959. */
  3960. SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param)
  3961. {
  3962. struct sched_param lp;
  3963. struct task_struct *p;
  3964. int retval;
  3965. if (!param || pid < 0)
  3966. return -EINVAL;
  3967. rcu_read_lock();
  3968. p = find_process_by_pid(pid);
  3969. retval = -ESRCH;
  3970. if (!p)
  3971. goto out_unlock;
  3972. retval = security_task_getscheduler(p);
  3973. if (retval)
  3974. goto out_unlock;
  3975. lp.sched_priority = p->rt_priority;
  3976. rcu_read_unlock();
  3977. /*
  3978. * This one might sleep, we cannot do it with a spinlock held ...
  3979. */
  3980. retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;
  3981. return retval;
  3982. out_unlock:
  3983. rcu_read_unlock();
  3984. return retval;
  3985. }
  3986. long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
  3987. {
  3988. cpumask_var_t cpus_allowed, new_mask;
  3989. struct task_struct *p;
  3990. int retval;
  3991. get_online_cpus();
  3992. rcu_read_lock();
  3993. p = find_process_by_pid(pid);
  3994. if (!p) {
  3995. rcu_read_unlock();
  3996. put_online_cpus();
  3997. return -ESRCH;
  3998. }
  3999. /* Prevent p going away */
  4000. get_task_struct(p);
  4001. rcu_read_unlock();
  4002. if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) {
  4003. retval = -ENOMEM;
  4004. goto out_put_task;
  4005. }
  4006. if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
  4007. retval = -ENOMEM;
  4008. goto out_free_cpus_allowed;
  4009. }
  4010. retval = -EPERM;
  4011. if (!check_same_owner(p) && !capable(CAP_SYS_NICE))
  4012. goto out_unlock;
  4013. retval = security_task_setscheduler(p, 0, NULL);
  4014. if (retval)
  4015. goto out_unlock;
  4016. cpuset_cpus_allowed(p, cpus_allowed);
  4017. cpumask_and(new_mask, in_mask, cpus_allowed);
  4018. again:
  4019. retval = set_cpus_allowed_ptr(p, new_mask);
  4020. if (!retval) {
  4021. cpuset_cpus_allowed(p, cpus_allowed);
  4022. if (!cpumask_subset(new_mask, cpus_allowed)) {
  4023. /*
  4024. * We must have raced with a concurrent cpuset
  4025. * update. Just reset the cpus_allowed to the
  4026. * cpuset's cpus_allowed
  4027. */
  4028. cpumask_copy(new_mask, cpus_allowed);
  4029. goto again;
  4030. }
  4031. }
  4032. out_unlock:
  4033. free_cpumask_var(new_mask);
  4034. out_free_cpus_allowed:
  4035. free_cpumask_var(cpus_allowed);
  4036. out_put_task:
  4037. put_task_struct(p);
  4038. put_online_cpus();
  4039. return retval;
  4040. }
  4041. static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
  4042. struct cpumask *new_mask)
  4043. {
  4044. if (len < cpumask_size())
  4045. cpumask_clear(new_mask);
  4046. else if (len > cpumask_size())
  4047. len = cpumask_size();
  4048. return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
  4049. }
  4050. /**
  4051. * sys_sched_setaffinity - set the cpu affinity of a process
  4052. * @pid: pid of the process
  4053. * @len: length in bytes of the bitmask pointed to by user_mask_ptr
  4054. * @user_mask_ptr: user-space pointer to the new cpu mask
  4055. */
  4056. SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len,
  4057. unsigned long __user *, user_mask_ptr)
  4058. {
  4059. cpumask_var_t new_mask;
  4060. int retval;
  4061. if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
  4062. return -ENOMEM;
  4063. retval = get_user_cpu_mask(user_mask_ptr, len, new_mask);
  4064. if (retval == 0)
  4065. retval = sched_setaffinity(pid, new_mask);
  4066. free_cpumask_var(new_mask);
  4067. return retval;
  4068. }
  4069. long sched_getaffinity(pid_t pid, struct cpumask *mask)
  4070. {
  4071. struct task_struct *p;
  4072. unsigned long flags;
  4073. struct rq *rq;
  4074. int retval;
  4075. get_online_cpus();
  4076. rcu_read_lock();
  4077. retval = -ESRCH;
  4078. p = find_process_by_pid(pid);
  4079. if (!p)
  4080. goto out_unlock;
  4081. retval = security_task_getscheduler(p);
  4082. if (retval)
  4083. goto out_unlock;
  4084. rq = task_rq_lock(p, &flags);
  4085. cpumask_and(mask, &p->cpus_allowed, cpu_online_mask);
  4086. task_rq_unlock(rq, &flags);
  4087. out_unlock:
  4088. rcu_read_unlock();
  4089. put_online_cpus();
  4090. return retval;
  4091. }
  4092. /**
  4093. * sys_sched_getaffinity - get the cpu affinity of a process
  4094. * @pid: pid of the process
  4095. * @len: length in bytes of the bitmask pointed to by user_mask_ptr
  4096. * @user_mask_ptr: user-space pointer to hold the current cpu mask
  4097. */
  4098. SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
  4099. unsigned long __user *, user_mask_ptr)
  4100. {
  4101. int ret;
  4102. cpumask_var_t mask;
  4103. if (len < cpumask_size())
  4104. return -EINVAL;
  4105. if (!alloc_cpumask_var(&mask, GFP_KERNEL))
  4106. return -ENOMEM;
  4107. ret = sched_getaffinity(pid, mask);
  4108. if (ret == 0) {
  4109. if (copy_to_user(user_mask_ptr, mask, cpumask_size()))
  4110. ret = -EFAULT;
  4111. else
  4112. ret = cpumask_size();
  4113. }
  4114. free_cpumask_var(mask);
  4115. return ret;
  4116. }
  4117. /**
  4118. * sys_sched_yield - yield the current processor to other threads.
  4119. *
  4120. * This function yields the current CPU to other tasks. If there are no
  4121. * other threads running on this CPU then this function will return.
  4122. */
  4123. SYSCALL_DEFINE0(sched_yield)
  4124. {
  4125. struct rq *rq = this_rq_lock();
  4126. schedstat_inc(rq, yld_count);
  4127. current->sched_class->yield_task(rq);
  4128. /*
  4129. * Since we are going to call schedule() anyway, there's
  4130. * no need to preempt or enable interrupts:
  4131. */
  4132. __release(rq->lock);
  4133. spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
  4134. do_raw_spin_unlock(&rq->lock);
  4135. preempt_enable_no_resched();
  4136. schedule();
  4137. return 0;
  4138. }
  4139. static inline int should_resched(void)
  4140. {
  4141. return need_resched() && !(preempt_count() & PREEMPT_ACTIVE);
  4142. }
  4143. static void __cond_resched(void)
  4144. {
  4145. add_preempt_count(PREEMPT_ACTIVE);
  4146. schedule();
  4147. sub_preempt_count(PREEMPT_ACTIVE);
  4148. }
  4149. int __sched _cond_resched(void)
  4150. {
  4151. if (should_resched()) {
  4152. __cond_resched();
  4153. return 1;
  4154. }
  4155. return 0;
  4156. }
  4157. EXPORT_SYMBOL(_cond_resched);
  4158. /*
  4159. * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
  4160. * call schedule, and on return reacquire the lock.
  4161. *
  4162. * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
  4163. * operations here to prevent schedule() from being called twice (once via
  4164. * spin_unlock(), once by hand).
  4165. */
  4166. int __cond_resched_lock(spinlock_t *lock)
  4167. {
  4168. int resched = should_resched();
  4169. int ret = 0;
  4170. lockdep_assert_held(lock);
  4171. if (spin_needbreak(lock) || resched) {
  4172. spin_unlock(lock);
  4173. if (resched)
  4174. __cond_resched();
  4175. else
  4176. cpu_relax();
  4177. ret = 1;
  4178. spin_lock(lock);
  4179. }
  4180. return ret;
  4181. }
  4182. EXPORT_SYMBOL(__cond_resched_lock);
  4183. int __sched __cond_resched_softirq(void)
  4184. {
  4185. BUG_ON(!in_softirq());
  4186. if (should_resched()) {
  4187. local_bh_enable();
  4188. __cond_resched();
  4189. local_bh_disable();
  4190. return 1;
  4191. }
  4192. return 0;
  4193. }
  4194. EXPORT_SYMBOL(__cond_resched_softirq);
  4195. /**
  4196. * yield - yield the current processor to other threads.
  4197. *
  4198. * This is a shortcut for kernel-space yielding - it marks the
  4199. * thread runnable and calls sys_sched_yield().
  4200. */
  4201. void __sched yield(void)
  4202. {
  4203. set_current_state(TASK_RUNNING);
  4204. sys_sched_yield();
  4205. }
  4206. EXPORT_SYMBOL(yield);
  4207. /*
  4208. * This task is about to go to sleep on IO. Increment rq->nr_iowait so
  4209. * that process accounting knows that this is a task in IO wait state.
  4210. */
  4211. void __sched io_schedule(void)
  4212. {
  4213. struct rq *rq = raw_rq();
  4214. delayacct_blkio_start();
  4215. atomic_inc(&rq->nr_iowait);
  4216. current->in_iowait = 1;
  4217. schedule();
  4218. current->in_iowait = 0;
  4219. atomic_dec(&rq->nr_iowait);
  4220. delayacct_blkio_end();
  4221. }
  4222. EXPORT_SYMBOL(io_schedule);
  4223. long __sched io_schedule_timeout(long timeout)
  4224. {
  4225. struct rq *rq = raw_rq();
  4226. long ret;
  4227. delayacct_blkio_start();
  4228. atomic_inc(&rq->nr_iowait);
  4229. current->in_iowait = 1;
  4230. ret = schedule_timeout(timeout);
  4231. current->in_iowait = 0;
  4232. atomic_dec(&rq->nr_iowait);
  4233. delayacct_blkio_end();
  4234. return ret;
  4235. }
  4236. /**
  4237. * sys_sched_get_priority_max - return maximum RT priority.
  4238. * @policy: scheduling class.
  4239. *
  4240. * this syscall returns the maximum rt_priority that can be used
  4241. * by a given scheduling class.
  4242. */
  4243. SYSCALL_DEFINE1(sched_get_priority_max, int, policy)
  4244. {
  4245. int ret = -EINVAL;
  4246. switch (policy) {
  4247. case SCHED_FIFO:
  4248. case SCHED_RR:
  4249. ret = MAX_USER_RT_PRIO-1;
  4250. break;
  4251. case SCHED_NORMAL:
  4252. case SCHED_BATCH:
  4253. case SCHED_IDLE:
  4254. ret = 0;
  4255. break;
  4256. }
  4257. return ret;
  4258. }
  4259. /**
  4260. * sys_sched_get_priority_min - return minimum RT priority.
  4261. * @policy: scheduling class.
  4262. *
  4263. * this syscall returns the minimum rt_priority that can be used
  4264. * by a given scheduling class.
  4265. */
  4266. SYSCALL_DEFINE1(sched_get_priority_min, int, policy)
  4267. {
  4268. int ret = -EINVAL;
  4269. switch (policy) {
  4270. case SCHED_FIFO:
  4271. case SCHED_RR:
  4272. ret = 1;
  4273. break;
  4274. case SCHED_NORMAL:
  4275. case SCHED_BATCH:
  4276. case SCHED_IDLE:
  4277. ret = 0;
  4278. }
  4279. return ret;
  4280. }
  4281. /**
  4282. * sys_sched_rr_get_interval - return the default timeslice of a process.
  4283. * @pid: pid of the process.
  4284. * @interval: userspace pointer to the timeslice value.
  4285. *
  4286. * this syscall writes the default timeslice value of a given process
  4287. * into the user-space timespec buffer. A value of '0' means infinity.
  4288. */
  4289. SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid,
  4290. struct timespec __user *, interval)
  4291. {
  4292. struct task_struct *p;
  4293. unsigned int time_slice;
  4294. unsigned long flags;
  4295. struct rq *rq;
  4296. int retval;
  4297. struct timespec t;
  4298. if (pid < 0)
  4299. return -EINVAL;
  4300. retval = -ESRCH;
  4301. rcu_read_lock();
  4302. p = find_process_by_pid(pid);
  4303. if (!p)
  4304. goto out_unlock;
  4305. retval = security_task_getscheduler(p);
  4306. if (retval)
  4307. goto out_unlock;
  4308. rq = task_rq_lock(p, &flags);
  4309. time_slice = p->sched_class->get_rr_interval(rq, p);
  4310. task_rq_unlock(rq, &flags);
  4311. rcu_read_unlock();
  4312. jiffies_to_timespec(time_slice, &t);
  4313. retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;
  4314. return retval;
  4315. out_unlock:
  4316. rcu_read_unlock();
  4317. return retval;
  4318. }
  4319. static const char stat_nam[] = TASK_STATE_TO_CHAR_STR;
  4320. void sched_show_task(struct task_struct *p)
  4321. {
  4322. unsigned long free = 0;
  4323. unsigned state;
  4324. state = p->state ? __ffs(p->state) + 1 : 0;
  4325. printk(KERN_INFO "%-13.13s %c", p->comm,
  4326. state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?');
  4327. #if BITS_PER_LONG == 32
  4328. if (state == TASK_RUNNING)
  4329. printk(KERN_CONT " running ");
  4330. else
  4331. printk(KERN_CONT " %08lx ", thread_saved_pc(p));
  4332. #else
  4333. if (state == TASK_RUNNING)
  4334. printk(KERN_CONT " running task ");
  4335. else
  4336. printk(KERN_CONT " %016lx ", thread_saved_pc(p));
  4337. #endif
  4338. #ifdef CONFIG_DEBUG_STACK_USAGE
  4339. free = stack_not_used(p);
  4340. #endif
  4341. printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free,
  4342. task_pid_nr(p), task_pid_nr(p->real_parent),
  4343. (unsigned long)task_thread_info(p)->flags);
  4344. show_stack(p, NULL);
  4345. }
  4346. void show_state_filter(unsigned long state_filter)
  4347. {
  4348. struct task_struct *g, *p;
  4349. #if BITS_PER_LONG == 32
  4350. printk(KERN_INFO
  4351. " task PC stack pid father\n");
  4352. #else
  4353. printk(KERN_INFO
  4354. " task PC stack pid father\n");
  4355. #endif
  4356. read_lock(&tasklist_lock);
  4357. do_each_thread(g, p) {
  4358. /*
  4359. * reset the NMI-timeout, listing all files on a slow
  4360. * console might take alot of time:
  4361. */
  4362. touch_nmi_watchdog();
  4363. if (!state_filter || (p->state & state_filter))
  4364. sched_show_task(p);
  4365. } while_each_thread(g, p);
  4366. touch_all_softlockup_watchdogs();
  4367. #ifdef CONFIG_SCHED_DEBUG
  4368. sysrq_sched_debug_show();
  4369. #endif
  4370. read_unlock(&tasklist_lock);
  4371. /*
  4372. * Only show locks if all tasks are dumped:
  4373. */
  4374. if (!state_filter)
  4375. debug_show_all_locks();
  4376. }
  4377. void __cpuinit init_idle_bootup_task(struct task_struct *idle)
  4378. {
  4379. idle->sched_class = &idle_sched_class;
  4380. }
  4381. /**
  4382. * init_idle - set up an idle thread for a given CPU
  4383. * @idle: task in question
  4384. * @cpu: cpu the idle task belongs to
  4385. *
  4386. * NOTE: this function does not set the idle thread's NEED_RESCHED
  4387. * flag, to make booting more robust.
  4388. */
  4389. void __cpuinit init_idle(struct task_struct *idle, int cpu)
  4390. {
  4391. struct rq *rq = cpu_rq(cpu);
  4392. unsigned long flags;
  4393. raw_spin_lock_irqsave(&rq->lock, flags);
  4394. __sched_fork(idle);
  4395. idle->state = TASK_RUNNING;
  4396. idle->se.exec_start = sched_clock();
  4397. cpumask_copy(&idle->cpus_allowed, cpumask_of(cpu));
  4398. __set_task_cpu(idle, cpu);
  4399. rq->curr = rq->idle = idle;
  4400. #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
  4401. idle->oncpu = 1;
  4402. #endif
  4403. raw_spin_unlock_irqrestore(&rq->lock, flags);
  4404. /* Set the preempt count _outside_ the spinlocks! */
  4405. #if defined(CONFIG_PREEMPT)
  4406. task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0);
  4407. #else
  4408. task_thread_info(idle)->preempt_count = 0;
  4409. #endif
  4410. /*
  4411. * The idle tasks have their own, simple scheduling class:
  4412. */
  4413. idle->sched_class = &idle_sched_class;
  4414. ftrace_graph_init_task(idle);
  4415. }
  4416. /*
  4417. * In a system that switches off the HZ timer nohz_cpu_mask
  4418. * indicates which cpus entered this state. This is used
  4419. * in the rcu update to wait only for active cpus. For system
  4420. * which do not switch off the HZ timer nohz_cpu_mask should
  4421. * always be CPU_BITS_NONE.
  4422. */
  4423. cpumask_var_t nohz_cpu_mask;
  4424. /*
  4425. * Increase the granularity value when there are more CPUs,
  4426. * because with more CPUs the 'effective latency' as visible
  4427. * to users decreases. But the relationship is not linear,
  4428. * so pick a second-best guess by going with the log2 of the
  4429. * number of CPUs.
  4430. *
  4431. * This idea comes from the SD scheduler of Con Kolivas:
  4432. */
  4433. static int get_update_sysctl_factor(void)
  4434. {
  4435. unsigned int cpus = min_t(int, num_online_cpus(), 8);
  4436. unsigned int factor;
  4437. switch (sysctl_sched_tunable_scaling) {
  4438. case SCHED_TUNABLESCALING_NONE:
  4439. factor = 1;
  4440. break;
  4441. case SCHED_TUNABLESCALING_LINEAR:
  4442. factor = cpus;
  4443. break;
  4444. case SCHED_TUNABLESCALING_LOG:
  4445. default:
  4446. factor = 1 + ilog2(cpus);
  4447. break;
  4448. }
  4449. return factor;
  4450. }
  4451. static void update_sysctl(void)
  4452. {
  4453. unsigned int factor = get_update_sysctl_factor();
  4454. #define SET_SYSCTL(name) \
  4455. (sysctl_##name = (factor) * normalized_sysctl_##name)
  4456. SET_SYSCTL(sched_min_granularity);
  4457. SET_SYSCTL(sched_latency);
  4458. SET_SYSCTL(sched_wakeup_granularity);
  4459. SET_SYSCTL(sched_shares_ratelimit);
  4460. #undef SET_SYSCTL
  4461. }
  4462. static inline void sched_init_granularity(void)
  4463. {
  4464. update_sysctl();
  4465. }
  4466. #ifdef CONFIG_SMP
  4467. /*
  4468. * This is how migration works:
  4469. *
  4470. * 1) we queue a struct migration_req structure in the source CPU's
  4471. * runqueue and wake up that CPU's migration thread.
  4472. * 2) we down() the locked semaphore => thread blocks.
  4473. * 3) migration thread wakes up (implicitly it forces the migrated
  4474. * thread off the CPU)
  4475. * 4) it gets the migration request and checks whether the migrated
  4476. * task is still in the wrong runqueue.
  4477. * 5) if it's in the wrong runqueue then the migration thread removes
  4478. * it and puts it into the right queue.
  4479. * 6) migration thread up()s the semaphore.
  4480. * 7) we wake up and the migration is done.
  4481. */
  4482. /*
  4483. * Change a given task's CPU affinity. Migrate the thread to a
  4484. * proper CPU and schedule it away if the CPU it's executing on
  4485. * is removed from the allowed bitmask.
  4486. *
  4487. * NOTE: the caller must have a valid reference to the task, the
  4488. * task must not exit() & deallocate itself prematurely. The
  4489. * call is not atomic; no spinlocks may be held.
  4490. */
  4491. int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
  4492. {
  4493. struct migration_req req;
  4494. unsigned long flags;
  4495. struct rq *rq;
  4496. int ret = 0;
  4497. rq = task_rq_lock(p, &flags);
  4498. if (!cpumask_intersects(new_mask, cpu_active_mask)) {
  4499. ret = -EINVAL;
  4500. goto out;
  4501. }
  4502. if (unlikely((p->flags & PF_THREAD_BOUND) && p != current &&
  4503. !cpumask_equal(&p->cpus_allowed, new_mask))) {
  4504. ret = -EINVAL;
  4505. goto out;
  4506. }
  4507. if (p->sched_class->set_cpus_allowed)
  4508. p->sched_class->set_cpus_allowed(p, new_mask);
  4509. else {
  4510. cpumask_copy(&p->cpus_allowed, new_mask);
  4511. p->rt.nr_cpus_allowed = cpumask_weight(new_mask);
  4512. }
  4513. /* Can the task run on the task's current CPU? If so, we're done */
  4514. if (cpumask_test_cpu(task_cpu(p), new_mask))
  4515. goto out;
  4516. if (migrate_task(p, cpumask_any_and(cpu_active_mask, new_mask), &req)) {
  4517. /* Need help from migration thread: drop lock and wait. */
  4518. struct task_struct *mt = rq->migration_thread;
  4519. get_task_struct(mt);
  4520. task_rq_unlock(rq, &flags);
  4521. wake_up_process(rq->migration_thread);
  4522. put_task_struct(mt);
  4523. wait_for_completion(&req.done);
  4524. tlb_migrate_finish(p->mm);
  4525. return 0;
  4526. }
  4527. out:
  4528. task_rq_unlock(rq, &flags);
  4529. return ret;
  4530. }
  4531. EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
  4532. /*
  4533. * Move (not current) task off this cpu, onto dest cpu. We're doing
  4534. * this because either it can't run here any more (set_cpus_allowed()
  4535. * away from this CPU, or CPU going down), or because we're
  4536. * attempting to rebalance this task on exec (sched_exec).
  4537. *
  4538. * So we race with normal scheduler movements, but that's OK, as long
  4539. * as the task is no longer on this CPU.
  4540. *
  4541. * Returns non-zero if task was successfully migrated.
  4542. */
  4543. static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
  4544. {
  4545. struct rq *rq_dest, *rq_src;
  4546. int ret = 0;
  4547. if (unlikely(!cpu_active(dest_cpu)))
  4548. return ret;
  4549. rq_src = cpu_rq(src_cpu);
  4550. rq_dest = cpu_rq(dest_cpu);
  4551. double_rq_lock(rq_src, rq_dest);
  4552. /* Already moved. */
  4553. if (task_cpu(p) != src_cpu)
  4554. goto done;
  4555. /* Affinity changed (again). */
  4556. if (!cpumask_test_cpu(dest_cpu, &p->cpus_allowed))
  4557. goto fail;
  4558. /*
  4559. * If we're not on a rq, the next wake-up will ensure we're
  4560. * placed properly.
  4561. */
  4562. if (p->se.on_rq) {
  4563. deactivate_task(rq_src, p, 0);
  4564. set_task_cpu(p, dest_cpu);
  4565. activate_task(rq_dest, p, 0);
  4566. check_preempt_curr(rq_dest, p, 0);
  4567. }
  4568. done:
  4569. ret = 1;
  4570. fail:
  4571. double_rq_unlock(rq_src, rq_dest);
  4572. return ret;
  4573. }
  4574. #define RCU_MIGRATION_IDLE 0
  4575. #define RCU_MIGRATION_NEED_QS 1
  4576. #define RCU_MIGRATION_GOT_QS 2
  4577. #define RCU_MIGRATION_MUST_SYNC 3
  4578. /*
  4579. * migration_thread - this is a highprio system thread that performs
  4580. * thread migration by bumping thread off CPU then 'pushing' onto
  4581. * another runqueue.
  4582. */
  4583. static int migration_thread(void *data)
  4584. {
  4585. int badcpu;
  4586. int cpu = (long)data;
  4587. struct rq *rq;
  4588. rq = cpu_rq(cpu);
  4589. BUG_ON(rq->migration_thread != current);
  4590. set_current_state(TASK_INTERRUPTIBLE);
  4591. while (!kthread_should_stop()) {
  4592. struct migration_req *req;
  4593. struct list_head *head;
  4594. raw_spin_lock_irq(&rq->lock);
  4595. if (cpu_is_offline(cpu)) {
  4596. raw_spin_unlock_irq(&rq->lock);
  4597. break;
  4598. }
  4599. if (rq->active_balance) {
  4600. active_load_balance(rq, cpu);
  4601. rq->active_balance = 0;
  4602. }
  4603. head = &rq->migration_queue;
  4604. if (list_empty(head)) {
  4605. raw_spin_unlock_irq(&rq->lock);
  4606. schedule();
  4607. set_current_state(TASK_INTERRUPTIBLE);
  4608. continue;
  4609. }
  4610. req = list_entry(head->next, struct migration_req, list);
  4611. list_del_init(head->next);
  4612. if (req->task != NULL) {
  4613. raw_spin_unlock(&rq->lock);
  4614. __migrate_task(req->task, cpu, req->dest_cpu);
  4615. } else if (likely(cpu == (badcpu = smp_processor_id()))) {
  4616. req->dest_cpu = RCU_MIGRATION_GOT_QS;
  4617. raw_spin_unlock(&rq->lock);
  4618. } else {
  4619. req->dest_cpu = RCU_MIGRATION_MUST_SYNC;
  4620. raw_spin_unlock(&rq->lock);
  4621. WARN_ONCE(1, "migration_thread() on CPU %d, expected %d\n", badcpu, cpu);
  4622. }
  4623. local_irq_enable();
  4624. complete(&req->done);
  4625. }
  4626. __set_current_state(TASK_RUNNING);
  4627. return 0;
  4628. }
  4629. #ifdef CONFIG_HOTPLUG_CPU
  4630. static int __migrate_task_irq(struct task_struct *p, int src_cpu, int dest_cpu)
  4631. {
  4632. int ret;
  4633. local_irq_disable();
  4634. ret = __migrate_task(p, src_cpu, dest_cpu);
  4635. local_irq_enable();
  4636. return ret;
  4637. }
  4638. /*
  4639. * Figure out where task on dead CPU should go, use force if necessary.
  4640. */
  4641. static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p)
  4642. {
  4643. int dest_cpu;
  4644. again:
  4645. dest_cpu = select_fallback_rq(dead_cpu, p);
  4646. /* It can have affinity changed while we were choosing. */
  4647. if (unlikely(!__migrate_task_irq(p, dead_cpu, dest_cpu)))
  4648. goto again;
  4649. }
  4650. /*
  4651. * While a dead CPU has no uninterruptible tasks queued at this point,
  4652. * it might still have a nonzero ->nr_uninterruptible counter, because
  4653. * for performance reasons the counter is not stricly tracking tasks to
  4654. * their home CPUs. So we just add the counter to another CPU's counter,
  4655. * to keep the global sum constant after CPU-down:
  4656. */
  4657. static void migrate_nr_uninterruptible(struct rq *rq_src)
  4658. {
  4659. struct rq *rq_dest = cpu_rq(cpumask_any(cpu_active_mask));
  4660. unsigned long flags;
  4661. local_irq_save(flags);
  4662. double_rq_lock(rq_src, rq_dest);
  4663. rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible;
  4664. rq_src->nr_uninterruptible = 0;
  4665. double_rq_unlock(rq_src, rq_dest);
  4666. local_irq_restore(flags);
  4667. }
  4668. /* Run through task list and migrate tasks from the dead cpu. */
  4669. static void migrate_live_tasks(int src_cpu)
  4670. {
  4671. struct task_struct *p, *t;
  4672. read_lock(&tasklist_lock);
  4673. do_each_thread(t, p) {
  4674. if (p == current)
  4675. continue;
  4676. if (task_cpu(p) == src_cpu)
  4677. move_task_off_dead_cpu(src_cpu, p);
  4678. } while_each_thread(t, p);
  4679. read_unlock(&tasklist_lock);
  4680. }
  4681. /*
  4682. * Schedules idle task to be the next runnable task on current CPU.
  4683. * It does so by boosting its priority to highest possible.
  4684. * Used by CPU offline code.
  4685. */
  4686. void sched_idle_next(void)
  4687. {
  4688. int this_cpu = smp_processor_id();
  4689. struct rq *rq = cpu_rq(this_cpu);
  4690. struct task_struct *p = rq->idle;
  4691. unsigned long flags;
  4692. /* cpu has to be offline */
  4693. BUG_ON(cpu_online(this_cpu));
  4694. /*
  4695. * Strictly not necessary since rest of the CPUs are stopped by now
  4696. * and interrupts disabled on the current cpu.
  4697. */
  4698. raw_spin_lock_irqsave(&rq->lock, flags);
  4699. __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
  4700. update_rq_clock(rq);
  4701. activate_task(rq, p, 0);
  4702. raw_spin_unlock_irqrestore(&rq->lock, flags);
  4703. }
  4704. /*
  4705. * Ensures that the idle task is using init_mm right before its cpu goes
  4706. * offline.
  4707. */
  4708. void idle_task_exit(void)
  4709. {
  4710. struct mm_struct *mm = current->active_mm;
  4711. BUG_ON(cpu_online(smp_processor_id()));
  4712. if (mm != &init_mm)
  4713. switch_mm(mm, &init_mm, current);
  4714. mmdrop(mm);
  4715. }
  4716. /* called under rq->lock with disabled interrupts */
  4717. static void migrate_dead(unsigned int dead_cpu, struct task_struct *p)
  4718. {
  4719. struct rq *rq = cpu_rq(dead_cpu);
  4720. /* Must be exiting, otherwise would be on tasklist. */
  4721. BUG_ON(!p->exit_state);
  4722. /* Cannot have done final schedule yet: would have vanished. */
  4723. BUG_ON(p->state == TASK_DEAD);
  4724. get_task_struct(p);
  4725. /*
  4726. * Drop lock around migration; if someone else moves it,
  4727. * that's OK. No task can be added to this CPU, so iteration is
  4728. * fine.
  4729. */
  4730. raw_spin_unlock_irq(&rq->lock);
  4731. move_task_off_dead_cpu(dead_cpu, p);
  4732. raw_spin_lock_irq(&rq->lock);
  4733. put_task_struct(p);
  4734. }
  4735. /* release_task() removes task from tasklist, so we won't find dead tasks. */
  4736. static void migrate_dead_tasks(unsigned int dead_cpu)
  4737. {
  4738. struct rq *rq = cpu_rq(dead_cpu);
  4739. struct task_struct *next;
  4740. for ( ; ; ) {
  4741. if (!rq->nr_running)
  4742. break;
  4743. update_rq_clock(rq);
  4744. next = pick_next_task(rq);
  4745. if (!next)
  4746. break;
  4747. next->sched_class->put_prev_task(rq, next);
  4748. migrate_dead(dead_cpu, next);
  4749. }
  4750. }
  4751. /*
  4752. * remove the tasks which were accounted by rq from calc_load_tasks.
  4753. */
  4754. static void calc_global_load_remove(struct rq *rq)
  4755. {
  4756. atomic_long_sub(rq->calc_load_active, &calc_load_tasks);
  4757. rq->calc_load_active = 0;
  4758. }
  4759. #endif /* CONFIG_HOTPLUG_CPU */
  4760. #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
  4761. static struct ctl_table sd_ctl_dir[] = {
  4762. {
  4763. .procname = "sched_domain",
  4764. .mode = 0555,
  4765. },
  4766. {}
  4767. };
  4768. static struct ctl_table sd_ctl_root[] = {
  4769. {
  4770. .procname = "kernel",
  4771. .mode = 0555,
  4772. .child = sd_ctl_dir,
  4773. },
  4774. {}
  4775. };
  4776. static struct ctl_table *sd_alloc_ctl_entry(int n)
  4777. {
  4778. struct ctl_table *entry =
  4779. kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL);
  4780. return entry;
  4781. }
  4782. static void sd_free_ctl_entry(struct ctl_table **tablep)
  4783. {
  4784. struct ctl_table *entry;
  4785. /*
  4786. * In the intermediate directories, both the child directory and
  4787. * procname are dynamically allocated and could fail but the mode
  4788. * will always be set. In the lowest directory the names are
  4789. * static strings and all have proc handlers.
  4790. */
  4791. for (entry = *tablep; entry->mode; entry++) {
  4792. if (entry->child)
  4793. sd_free_ctl_entry(&entry->child);
  4794. if (entry->proc_handler == NULL)
  4795. kfree(entry->procname);
  4796. }
  4797. kfree(*tablep);
  4798. *tablep = NULL;
  4799. }
  4800. static void
  4801. set_table_entry(struct ctl_table *entry,
  4802. const char *procname, void *data, int maxlen,
  4803. mode_t mode, proc_handler *proc_handler)
  4804. {
  4805. entry->procname = procname;
  4806. entry->data = data;
  4807. entry->maxlen = maxlen;
  4808. entry->mode = mode;
  4809. entry->proc_handler = proc_handler;
  4810. }
  4811. static struct ctl_table *
  4812. sd_alloc_ctl_domain_table(struct sched_domain *sd)
  4813. {
  4814. struct ctl_table *table = sd_alloc_ctl_entry(13);
  4815. if (table == NULL)
  4816. return NULL;
  4817. set_table_entry(&table[0], "min_interval", &sd->min_interval,
  4818. sizeof(long), 0644, proc_doulongvec_minmax);
  4819. set_table_entry(&table[1], "max_interval", &sd->max_interval,
  4820. sizeof(long), 0644, proc_doulongvec_minmax);
  4821. set_table_entry(&table[2], "busy_idx", &sd->busy_idx,
  4822. sizeof(int), 0644, proc_dointvec_minmax);
  4823. set_table_entry(&table[3], "idle_idx", &sd->idle_idx,
  4824. sizeof(int), 0644, proc_dointvec_minmax);
  4825. set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx,
  4826. sizeof(int), 0644, proc_dointvec_minmax);
  4827. set_table_entry(&table[5], "wake_idx", &sd->wake_idx,
  4828. sizeof(int), 0644, proc_dointvec_minmax);
  4829. set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx,
  4830. sizeof(int), 0644, proc_dointvec_minmax);
  4831. set_table_entry(&table[7], "busy_factor", &sd->busy_factor,
  4832. sizeof(int), 0644, proc_dointvec_minmax);
  4833. set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct,
  4834. sizeof(int), 0644, proc_dointvec_minmax);
  4835. set_table_entry(&table[9], "cache_nice_tries",
  4836. &sd->cache_nice_tries,
  4837. sizeof(int), 0644, proc_dointvec_minmax);
  4838. set_table_entry(&table[10], "flags", &sd->flags,
  4839. sizeof(int), 0644, proc_dointvec_minmax);
  4840. set_table_entry(&table[11], "name", sd->name,
  4841. CORENAME_MAX_SIZE, 0444, proc_dostring);
  4842. /* &table[12] is terminator */
  4843. return table;
  4844. }
  4845. static ctl_table *sd_alloc_ctl_cpu_table(int cpu)
  4846. {
  4847. struct ctl_table *entry, *table;
  4848. struct sched_domain *sd;
  4849. int domain_num = 0, i;
  4850. char buf[32];
  4851. for_each_domain(cpu, sd)
  4852. domain_num++;
  4853. entry = table = sd_alloc_ctl_entry(domain_num + 1);
  4854. if (table == NULL)
  4855. return NULL;
  4856. i = 0;
  4857. for_each_domain(cpu, sd) {
  4858. snprintf(buf, 32, "domain%d", i);
  4859. entry->procname = kstrdup(buf, GFP_KERNEL);
  4860. entry->mode = 0555;
  4861. entry->child = sd_alloc_ctl_domain_table(sd);
  4862. entry++;
  4863. i++;
  4864. }
  4865. return table;
  4866. }
  4867. static struct ctl_table_header *sd_sysctl_header;
  4868. static void register_sched_domain_sysctl(void)
  4869. {
  4870. int i, cpu_num = num_possible_cpus();
  4871. struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1);
  4872. char buf[32];
  4873. WARN_ON(sd_ctl_dir[0].child);
  4874. sd_ctl_dir[0].child = entry;
  4875. if (entry == NULL)
  4876. return;
  4877. for_each_possible_cpu(i) {
  4878. snprintf(buf, 32, "cpu%d", i);
  4879. entry->procname = kstrdup(buf, GFP_KERNEL);
  4880. entry->mode = 0555;
  4881. entry->child = sd_alloc_ctl_cpu_table(i);
  4882. entry++;
  4883. }
  4884. WARN_ON(sd_sysctl_header);
  4885. sd_sysctl_header = register_sysctl_table(sd_ctl_root);
  4886. }
  4887. /* may be called multiple times per register */
  4888. static void unregister_sched_domain_sysctl(void)
  4889. {
  4890. if (sd_sysctl_header)
  4891. unregister_sysctl_table(sd_sysctl_header);
  4892. sd_sysctl_header = NULL;
  4893. if (sd_ctl_dir[0].child)
  4894. sd_free_ctl_entry(&sd_ctl_dir[0].child);
  4895. }
  4896. #else
  4897. static void register_sched_domain_sysctl(void)
  4898. {
  4899. }
  4900. static void unregister_sched_domain_sysctl(void)
  4901. {
  4902. }
  4903. #endif
  4904. static void set_rq_online(struct rq *rq)
  4905. {
  4906. if (!rq->online) {
  4907. const struct sched_class *class;
  4908. cpumask_set_cpu(rq->cpu, rq->rd->online);
  4909. rq->online = 1;
  4910. for_each_class(class) {
  4911. if (class->rq_online)
  4912. class->rq_online(rq);
  4913. }
  4914. }
  4915. }
  4916. static void set_rq_offline(struct rq *rq)
  4917. {
  4918. if (rq->online) {
  4919. const struct sched_class *class;
  4920. for_each_class(class) {
  4921. if (class->rq_offline)
  4922. class->rq_offline(rq);
  4923. }
  4924. cpumask_clear_cpu(rq->cpu, rq->rd->online);
  4925. rq->online = 0;
  4926. }
  4927. }
  4928. /*
  4929. * migration_call - callback that gets triggered when a CPU is added.
  4930. * Here we can start up the necessary migration thread for the new CPU.
  4931. */
  4932. static int __cpuinit
  4933. migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
  4934. {
  4935. struct task_struct *p;
  4936. int cpu = (long)hcpu;
  4937. unsigned long flags;
  4938. struct rq *rq;
  4939. switch (action) {
  4940. case CPU_UP_PREPARE:
  4941. case CPU_UP_PREPARE_FROZEN:
  4942. p = kthread_create(migration_thread, hcpu, "migration/%d", cpu);
  4943. if (IS_ERR(p))
  4944. return NOTIFY_BAD;
  4945. kthread_bind(p, cpu);
  4946. /* Must be high prio: stop_machine expects to yield to it. */
  4947. rq = task_rq_lock(p, &flags);
  4948. __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
  4949. task_rq_unlock(rq, &flags);
  4950. get_task_struct(p);
  4951. cpu_rq(cpu)->migration_thread = p;
  4952. rq->calc_load_update = calc_load_update;
  4953. break;
  4954. case CPU_ONLINE:
  4955. case CPU_ONLINE_FROZEN:
  4956. /* Strictly unnecessary, as first user will wake it. */
  4957. wake_up_process(cpu_rq(cpu)->migration_thread);
  4958. /* Update our root-domain */
  4959. rq = cpu_rq(cpu);
  4960. raw_spin_lock_irqsave(&rq->lock, flags);
  4961. if (rq->rd) {
  4962. BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
  4963. set_rq_online(rq);
  4964. }
  4965. raw_spin_unlock_irqrestore(&rq->lock, flags);
  4966. break;
  4967. #ifdef CONFIG_HOTPLUG_CPU
  4968. case CPU_UP_CANCELED:
  4969. case CPU_UP_CANCELED_FROZEN:
  4970. if (!cpu_rq(cpu)->migration_thread)
  4971. break;
  4972. /* Unbind it from offline cpu so it can run. Fall thru. */
  4973. kthread_bind(cpu_rq(cpu)->migration_thread,
  4974. cpumask_any(cpu_online_mask));
  4975. kthread_stop(cpu_rq(cpu)->migration_thread);
  4976. put_task_struct(cpu_rq(cpu)->migration_thread);
  4977. cpu_rq(cpu)->migration_thread = NULL;
  4978. break;
  4979. case CPU_DEAD:
  4980. case CPU_DEAD_FROZEN:
  4981. cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */
  4982. migrate_live_tasks(cpu);
  4983. rq = cpu_rq(cpu);
  4984. kthread_stop(rq->migration_thread);
  4985. put_task_struct(rq->migration_thread);
  4986. rq->migration_thread = NULL;
  4987. /* Idle task back to normal (off runqueue, low prio) */
  4988. raw_spin_lock_irq(&rq->lock);
  4989. update_rq_clock(rq);
  4990. deactivate_task(rq, rq->idle, 0);
  4991. __setscheduler(rq, rq->idle, SCHED_NORMAL, 0);
  4992. rq->idle->sched_class = &idle_sched_class;
  4993. migrate_dead_tasks(cpu);
  4994. raw_spin_unlock_irq(&rq->lock);
  4995. cpuset_unlock();
  4996. migrate_nr_uninterruptible(rq);
  4997. BUG_ON(rq->nr_running != 0);
  4998. calc_global_load_remove(rq);
  4999. /*
  5000. * No need to migrate the tasks: it was best-effort if
  5001. * they didn't take sched_hotcpu_mutex. Just wake up
  5002. * the requestors.
  5003. */
  5004. raw_spin_lock_irq(&rq->lock);
  5005. while (!list_empty(&rq->migration_queue)) {
  5006. struct migration_req *req;
  5007. req = list_entry(rq->migration_queue.next,
  5008. struct migration_req, list);
  5009. list_del_init(&req->list);
  5010. raw_spin_unlock_irq(&rq->lock);
  5011. complete(&req->done);
  5012. raw_spin_lock_irq(&rq->lock);
  5013. }
  5014. raw_spin_unlock_irq(&rq->lock);
  5015. break;
  5016. case CPU_DYING:
  5017. case CPU_DYING_FROZEN:
  5018. /* Update our root-domain */
  5019. rq = cpu_rq(cpu);
  5020. raw_spin_lock_irqsave(&rq->lock, flags);
  5021. if (rq->rd) {
  5022. BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
  5023. set_rq_offline(rq);
  5024. }
  5025. raw_spin_unlock_irqrestore(&rq->lock, flags);
  5026. break;
  5027. #endif
  5028. }
  5029. return NOTIFY_OK;
  5030. }
  5031. /*
  5032. * Register at high priority so that task migration (migrate_all_tasks)
  5033. * happens before everything else. This has to be lower priority than
  5034. * the notifier in the perf_event subsystem, though.
  5035. */
  5036. static struct notifier_block __cpuinitdata migration_notifier = {
  5037. .notifier_call = migration_call,
  5038. .priority = 10
  5039. };
  5040. static int __init migration_init(void)
  5041. {
  5042. void *cpu = (void *)(long)smp_processor_id();
  5043. int err;
  5044. /* Start one for the boot CPU: */
  5045. err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
  5046. BUG_ON(err == NOTIFY_BAD);
  5047. migration_call(&migration_notifier, CPU_ONLINE, cpu);
  5048. register_cpu_notifier(&migration_notifier);
  5049. return 0;
  5050. }
  5051. early_initcall(migration_init);
  5052. #endif
  5053. #ifdef CONFIG_SMP
  5054. #ifdef CONFIG_SCHED_DEBUG
  5055. static __read_mostly int sched_domain_debug_enabled;
  5056. static int __init sched_domain_debug_setup(char *str)
  5057. {
  5058. sched_domain_debug_enabled = 1;
  5059. return 0;
  5060. }
  5061. early_param("sched_debug", sched_domain_debug_setup);
  5062. static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
  5063. struct cpumask *groupmask)
  5064. {
  5065. struct sched_group *group = sd->groups;
  5066. char str[256];
  5067. cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd));
  5068. cpumask_clear(groupmask);
  5069. printk(KERN_DEBUG "%*s domain %d: ", level, "", level);
  5070. if (!(sd->flags & SD_LOAD_BALANCE)) {
  5071. printk("does not load-balance\n");
  5072. if (sd->parent)
  5073. printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain"
  5074. " has parent");
  5075. return -1;
  5076. }
  5077. printk(KERN_CONT "span %s level %s\n", str, sd->name);
  5078. if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) {
  5079. printk(KERN_ERR "ERROR: domain->span does not contain "
  5080. "CPU%d\n", cpu);
  5081. }
  5082. if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) {
  5083. printk(KERN_ERR "ERROR: domain->groups does not contain"
  5084. " CPU%d\n", cpu);
  5085. }
  5086. printk(KERN_DEBUG "%*s groups:", level + 1, "");
  5087. do {
  5088. if (!group) {
  5089. printk("\n");
  5090. printk(KERN_ERR "ERROR: group is NULL\n");
  5091. break;
  5092. }
  5093. if (!group->cpu_power) {
  5094. printk(KERN_CONT "\n");
  5095. printk(KERN_ERR "ERROR: domain->cpu_power not "
  5096. "set\n");
  5097. break;
  5098. }
  5099. if (!cpumask_weight(sched_group_cpus(group))) {
  5100. printk(KERN_CONT "\n");
  5101. printk(KERN_ERR "ERROR: empty group\n");
  5102. break;
  5103. }
  5104. if (cpumask_intersects(groupmask, sched_group_cpus(group))) {
  5105. printk(KERN_CONT "\n");
  5106. printk(KERN_ERR "ERROR: repeated CPUs\n");
  5107. break;
  5108. }
  5109. cpumask_or(groupmask, groupmask, sched_group_cpus(group));
  5110. cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group));
  5111. printk(KERN_CONT " %s", str);
  5112. if (group->cpu_power != SCHED_LOAD_SCALE) {
  5113. printk(KERN_CONT " (cpu_power = %d)",
  5114. group->cpu_power);
  5115. }
  5116. group = group->next;
  5117. } while (group != sd->groups);
  5118. printk(KERN_CONT "\n");
  5119. if (!cpumask_equal(sched_domain_span(sd), groupmask))
  5120. printk(KERN_ERR "ERROR: groups don't span domain->span\n");
  5121. if (sd->parent &&
  5122. !cpumask_subset(groupmask, sched_domain_span(sd->parent)))
  5123. printk(KERN_ERR "ERROR: parent span is not a superset "
  5124. "of domain->span\n");
  5125. return 0;
  5126. }
  5127. static void sched_domain_debug(struct sched_domain *sd, int cpu)
  5128. {
  5129. cpumask_var_t groupmask;
  5130. int level = 0;
  5131. if (!sched_domain_debug_enabled)
  5132. return;
  5133. if (!sd) {
  5134. printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
  5135. return;
  5136. }
  5137. printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu);
  5138. if (!alloc_cpumask_var(&groupmask, GFP_KERNEL)) {
  5139. printk(KERN_DEBUG "Cannot load-balance (out of memory)\n");
  5140. return;
  5141. }
  5142. for (;;) {
  5143. if (sched_domain_debug_one(sd, cpu, level, groupmask))
  5144. break;
  5145. level++;
  5146. sd = sd->parent;
  5147. if (!sd)
  5148. break;
  5149. }
  5150. free_cpumask_var(groupmask);
  5151. }
  5152. #else /* !CONFIG_SCHED_DEBUG */
  5153. # define sched_domain_debug(sd, cpu) do { } while (0)
  5154. #endif /* CONFIG_SCHED_DEBUG */
  5155. static int sd_degenerate(struct sched_domain *sd)
  5156. {
  5157. if (cpumask_weight(sched_domain_span(sd)) == 1)
  5158. return 1;
  5159. /* Following flags need at least 2 groups */
  5160. if (sd->flags & (SD_LOAD_BALANCE |
  5161. SD_BALANCE_NEWIDLE |
  5162. SD_BALANCE_FORK |
  5163. SD_BALANCE_EXEC |
  5164. SD_SHARE_CPUPOWER |
  5165. SD_SHARE_PKG_RESOURCES)) {
  5166. if (sd->groups != sd->groups->next)
  5167. return 0;
  5168. }
  5169. /* Following flags don't use groups */
  5170. if (sd->flags & (SD_WAKE_AFFINE))
  5171. return 0;
  5172. return 1;
  5173. }
  5174. static int
  5175. sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
  5176. {
  5177. unsigned long cflags = sd->flags, pflags = parent->flags;
  5178. if (sd_degenerate(parent))
  5179. return 1;
  5180. if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent)))
  5181. return 0;
  5182. /* Flags needing groups don't count if only 1 group in parent */
  5183. if (parent->groups == parent->groups->next) {
  5184. pflags &= ~(SD_LOAD_BALANCE |
  5185. SD_BALANCE_NEWIDLE |
  5186. SD_BALANCE_FORK |
  5187. SD_BALANCE_EXEC |
  5188. SD_SHARE_CPUPOWER |
  5189. SD_SHARE_PKG_RESOURCES);
  5190. if (nr_node_ids == 1)
  5191. pflags &= ~SD_SERIALIZE;
  5192. }
  5193. if (~cflags & pflags)
  5194. return 0;
  5195. return 1;
  5196. }
  5197. static void free_rootdomain(struct root_domain *rd)
  5198. {
  5199. synchronize_sched();
  5200. cpupri_cleanup(&rd->cpupri);
  5201. free_cpumask_var(rd->rto_mask);
  5202. free_cpumask_var(rd->online);
  5203. free_cpumask_var(rd->span);
  5204. kfree(rd);
  5205. }
  5206. static void rq_attach_root(struct rq *rq, struct root_domain *rd)
  5207. {
  5208. struct root_domain *old_rd = NULL;
  5209. unsigned long flags;
  5210. raw_spin_lock_irqsave(&rq->lock, flags);
  5211. if (rq->rd) {
  5212. old_rd = rq->rd;
  5213. if (cpumask_test_cpu(rq->cpu, old_rd->online))
  5214. set_rq_offline(rq);
  5215. cpumask_clear_cpu(rq->cpu, old_rd->span);
  5216. /*
  5217. * If we dont want to free the old_rt yet then
  5218. * set old_rd to NULL to skip the freeing later
  5219. * in this function:
  5220. */
  5221. if (!atomic_dec_and_test(&old_rd->refcount))
  5222. old_rd = NULL;
  5223. }
  5224. atomic_inc(&rd->refcount);
  5225. rq->rd = rd;
  5226. cpumask_set_cpu(rq->cpu, rd->span);
  5227. if (cpumask_test_cpu(rq->cpu, cpu_active_mask))
  5228. set_rq_online(rq);
  5229. raw_spin_unlock_irqrestore(&rq->lock, flags);
  5230. if (old_rd)
  5231. free_rootdomain(old_rd);
  5232. }
  5233. static int init_rootdomain(struct root_domain *rd, bool bootmem)
  5234. {
  5235. gfp_t gfp = GFP_KERNEL;
  5236. memset(rd, 0, sizeof(*rd));
  5237. if (bootmem)
  5238. gfp = GFP_NOWAIT;
  5239. if (!alloc_cpumask_var(&rd->span, gfp))
  5240. goto out;
  5241. if (!alloc_cpumask_var(&rd->online, gfp))
  5242. goto free_span;
  5243. if (!alloc_cpumask_var(&rd->rto_mask, gfp))
  5244. goto free_online;
  5245. if (cpupri_init(&rd->cpupri, bootmem) != 0)
  5246. goto free_rto_mask;
  5247. return 0;
  5248. free_rto_mask:
  5249. free_cpumask_var(rd->rto_mask);
  5250. free_online:
  5251. free_cpumask_var(rd->online);
  5252. free_span:
  5253. free_cpumask_var(rd->span);
  5254. out:
  5255. return -ENOMEM;
  5256. }
  5257. static void init_defrootdomain(void)
  5258. {
  5259. init_rootdomain(&def_root_domain, true);
  5260. atomic_set(&def_root_domain.refcount, 1);
  5261. }
  5262. static struct root_domain *alloc_rootdomain(void)
  5263. {
  5264. struct root_domain *rd;
  5265. rd = kmalloc(sizeof(*rd), GFP_KERNEL);
  5266. if (!rd)
  5267. return NULL;
  5268. if (init_rootdomain(rd, false) != 0) {
  5269. kfree(rd);
  5270. return NULL;
  5271. }
  5272. return rd;
  5273. }
  5274. /*
  5275. * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
  5276. * hold the hotplug lock.
  5277. */
  5278. static void
  5279. cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
  5280. {
  5281. struct rq *rq = cpu_rq(cpu);
  5282. struct sched_domain *tmp;
  5283. /* Remove the sched domains which do not contribute to scheduling. */
  5284. for (tmp = sd; tmp; ) {
  5285. struct sched_domain *parent = tmp->parent;
  5286. if (!parent)
  5287. break;
  5288. if (sd_parent_degenerate(tmp, parent)) {
  5289. tmp->parent = parent->parent;
  5290. if (parent->parent)
  5291. parent->parent->child = tmp;
  5292. } else
  5293. tmp = tmp->parent;
  5294. }
  5295. if (sd && sd_degenerate(sd)) {
  5296. sd = sd->parent;
  5297. if (sd)
  5298. sd->child = NULL;
  5299. }
  5300. sched_domain_debug(sd, cpu);
  5301. rq_attach_root(rq, rd);
  5302. rcu_assign_pointer(rq->sd, sd);
  5303. }
  5304. /* cpus with isolated domains */
  5305. static cpumask_var_t cpu_isolated_map;
  5306. /* Setup the mask of cpus configured for isolated domains */
  5307. static int __init isolated_cpu_setup(char *str)
  5308. {
  5309. alloc_bootmem_cpumask_var(&cpu_isolated_map);
  5310. cpulist_parse(str, cpu_isolated_map);
  5311. return 1;
  5312. }
  5313. __setup("isolcpus=", isolated_cpu_setup);
  5314. /*
  5315. * init_sched_build_groups takes the cpumask we wish to span, and a pointer
  5316. * to a function which identifies what group(along with sched group) a CPU
  5317. * belongs to. The return value of group_fn must be a >= 0 and < nr_cpu_ids
  5318. * (due to the fact that we keep track of groups covered with a struct cpumask).
  5319. *
  5320. * init_sched_build_groups will build a circular linked list of the groups
  5321. * covered by the given span, and will set each group's ->cpumask correctly,
  5322. * and ->cpu_power to 0.
  5323. */
  5324. static void
  5325. init_sched_build_groups(const struct cpumask *span,
  5326. const struct cpumask *cpu_map,
  5327. int (*group_fn)(int cpu, const struct cpumask *cpu_map,
  5328. struct sched_group **sg,
  5329. struct cpumask *tmpmask),
  5330. struct cpumask *covered, struct cpumask *tmpmask)
  5331. {
  5332. struct sched_group *first = NULL, *last = NULL;
  5333. int i;
  5334. cpumask_clear(covered);
  5335. for_each_cpu(i, span) {
  5336. struct sched_group *sg;
  5337. int group = group_fn(i, cpu_map, &sg, tmpmask);
  5338. int j;
  5339. if (cpumask_test_cpu(i, covered))
  5340. continue;
  5341. cpumask_clear(sched_group_cpus(sg));
  5342. sg->cpu_power = 0;
  5343. for_each_cpu(j, span) {
  5344. if (group_fn(j, cpu_map, NULL, tmpmask) != group)
  5345. continue;
  5346. cpumask_set_cpu(j, covered);
  5347. cpumask_set_cpu(j, sched_group_cpus(sg));
  5348. }
  5349. if (!first)
  5350. first = sg;
  5351. if (last)
  5352. last->next = sg;
  5353. last = sg;
  5354. }
  5355. last->next = first;
  5356. }
  5357. #define SD_NODES_PER_DOMAIN 16
  5358. #ifdef CONFIG_NUMA
  5359. /**
  5360. * find_next_best_node - find the next node to include in a sched_domain
  5361. * @node: node whose sched_domain we're building
  5362. * @used_nodes: nodes already in the sched_domain
  5363. *
  5364. * Find the next node to include in a given scheduling domain. Simply
  5365. * finds the closest node not already in the @used_nodes map.
  5366. *
  5367. * Should use nodemask_t.
  5368. */
  5369. static int find_next_best_node(int node, nodemask_t *used_nodes)
  5370. {
  5371. int i, n, val, min_val, best_node = 0;
  5372. min_val = INT_MAX;
  5373. for (i = 0; i < nr_node_ids; i++) {
  5374. /* Start at @node */
  5375. n = (node + i) % nr_node_ids;
  5376. if (!nr_cpus_node(n))
  5377. continue;
  5378. /* Skip already used nodes */
  5379. if (node_isset(n, *used_nodes))
  5380. continue;
  5381. /* Simple min distance search */
  5382. val = node_distance(node, n);
  5383. if (val < min_val) {
  5384. min_val = val;
  5385. best_node = n;
  5386. }
  5387. }
  5388. node_set(best_node, *used_nodes);
  5389. return best_node;
  5390. }
  5391. /**
  5392. * sched_domain_node_span - get a cpumask for a node's sched_domain
  5393. * @node: node whose cpumask we're constructing
  5394. * @span: resulting cpumask
  5395. *
  5396. * Given a node, construct a good cpumask for its sched_domain to span. It
  5397. * should be one that prevents unnecessary balancing, but also spreads tasks
  5398. * out optimally.
  5399. */
  5400. static void sched_domain_node_span(int node, struct cpumask *span)
  5401. {
  5402. nodemask_t used_nodes;
  5403. int i;
  5404. cpumask_clear(span);
  5405. nodes_clear(used_nodes);
  5406. cpumask_or(span, span, cpumask_of_node(node));
  5407. node_set(node, used_nodes);
  5408. for (i = 1; i < SD_NODES_PER_DOMAIN; i++) {
  5409. int next_node = find_next_best_node(node, &used_nodes);
  5410. cpumask_or(span, span, cpumask_of_node(next_node));
  5411. }
  5412. }
  5413. #endif /* CONFIG_NUMA */
  5414. int sched_smt_power_savings = 0, sched_mc_power_savings = 0;
  5415. /*
  5416. * The cpus mask in sched_group and sched_domain hangs off the end.
  5417. *
  5418. * ( See the the comments in include/linux/sched.h:struct sched_group
  5419. * and struct sched_domain. )
  5420. */
  5421. struct static_sched_group {
  5422. struct sched_group sg;
  5423. DECLARE_BITMAP(cpus, CONFIG_NR_CPUS);
  5424. };
  5425. struct static_sched_domain {
  5426. struct sched_domain sd;
  5427. DECLARE_BITMAP(span, CONFIG_NR_CPUS);
  5428. };
  5429. struct s_data {
  5430. #ifdef CONFIG_NUMA
  5431. int sd_allnodes;
  5432. cpumask_var_t domainspan;
  5433. cpumask_var_t covered;
  5434. cpumask_var_t notcovered;
  5435. #endif
  5436. cpumask_var_t nodemask;
  5437. cpumask_var_t this_sibling_map;
  5438. cpumask_var_t this_core_map;
  5439. cpumask_var_t send_covered;
  5440. cpumask_var_t tmpmask;
  5441. struct sched_group **sched_group_nodes;
  5442. struct root_domain *rd;
  5443. };
  5444. enum s_alloc {
  5445. sa_sched_groups = 0,
  5446. sa_rootdomain,
  5447. sa_tmpmask,
  5448. sa_send_covered,
  5449. sa_this_core_map,
  5450. sa_this_sibling_map,
  5451. sa_nodemask,
  5452. sa_sched_group_nodes,
  5453. #ifdef CONFIG_NUMA
  5454. sa_notcovered,
  5455. sa_covered,
  5456. sa_domainspan,
  5457. #endif
  5458. sa_none,
  5459. };
  5460. /*
  5461. * SMT sched-domains:
  5462. */
  5463. #ifdef CONFIG_SCHED_SMT
  5464. static DEFINE_PER_CPU(struct static_sched_domain, cpu_domains);
  5465. static DEFINE_PER_CPU(struct static_sched_group, sched_groups);
  5466. static int
  5467. cpu_to_cpu_group(int cpu, const struct cpumask *cpu_map,
  5468. struct sched_group **sg, struct cpumask *unused)
  5469. {
  5470. if (sg)
  5471. *sg = &per_cpu(sched_groups, cpu).sg;
  5472. return cpu;
  5473. }
  5474. #endif /* CONFIG_SCHED_SMT */
  5475. /*
  5476. * multi-core sched-domains:
  5477. */
  5478. #ifdef CONFIG_SCHED_MC
  5479. static DEFINE_PER_CPU(struct static_sched_domain, core_domains);
  5480. static DEFINE_PER_CPU(struct static_sched_group, sched_group_core);
  5481. #endif /* CONFIG_SCHED_MC */
  5482. #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
  5483. static int
  5484. cpu_to_core_group(int cpu, const struct cpumask *cpu_map,
  5485. struct sched_group **sg, struct cpumask *mask)
  5486. {
  5487. int group;
  5488. cpumask_and(mask, topology_thread_cpumask(cpu), cpu_map);
  5489. group = cpumask_first(mask);
  5490. if (sg)
  5491. *sg = &per_cpu(sched_group_core, group).sg;
  5492. return group;
  5493. }
  5494. #elif defined(CONFIG_SCHED_MC)
  5495. static int
  5496. cpu_to_core_group(int cpu, const struct cpumask *cpu_map,
  5497. struct sched_group **sg, struct cpumask *unused)
  5498. {
  5499. if (sg)
  5500. *sg = &per_cpu(sched_group_core, cpu).sg;
  5501. return cpu;
  5502. }
  5503. #endif
  5504. static DEFINE_PER_CPU(struct static_sched_domain, phys_domains);
  5505. static DEFINE_PER_CPU(struct static_sched_group, sched_group_phys);
  5506. static int
  5507. cpu_to_phys_group(int cpu, const struct cpumask *cpu_map,
  5508. struct sched_group **sg, struct cpumask *mask)
  5509. {
  5510. int group;
  5511. #ifdef CONFIG_SCHED_MC
  5512. cpumask_and(mask, cpu_coregroup_mask(cpu), cpu_map);
  5513. group = cpumask_first(mask);
  5514. #elif defined(CONFIG_SCHED_SMT)
  5515. cpumask_and(mask, topology_thread_cpumask(cpu), cpu_map);
  5516. group = cpumask_first(mask);
  5517. #else
  5518. group = cpu;
  5519. #endif
  5520. if (sg)
  5521. *sg = &per_cpu(sched_group_phys, group).sg;
  5522. return group;
  5523. }
  5524. #ifdef CONFIG_NUMA
  5525. /*
  5526. * The init_sched_build_groups can't handle what we want to do with node
  5527. * groups, so roll our own. Now each node has its own list of groups which
  5528. * gets dynamically allocated.
  5529. */
  5530. static DEFINE_PER_CPU(struct static_sched_domain, node_domains);
  5531. static struct sched_group ***sched_group_nodes_bycpu;
  5532. static DEFINE_PER_CPU(struct static_sched_domain, allnodes_domains);
  5533. static DEFINE_PER_CPU(struct static_sched_group, sched_group_allnodes);
  5534. static int cpu_to_allnodes_group(int cpu, const struct cpumask *cpu_map,
  5535. struct sched_group **sg,
  5536. struct cpumask *nodemask)
  5537. {
  5538. int group;
  5539. cpumask_and(nodemask, cpumask_of_node(cpu_to_node(cpu)), cpu_map);
  5540. group = cpumask_first(nodemask);
  5541. if (sg)
  5542. *sg = &per_cpu(sched_group_allnodes, group).sg;
  5543. return group;
  5544. }
  5545. static void init_numa_sched_groups_power(struct sched_group *group_head)
  5546. {
  5547. struct sched_group *sg = group_head;
  5548. int j;
  5549. if (!sg)
  5550. return;
  5551. do {
  5552. for_each_cpu(j, sched_group_cpus(sg)) {
  5553. struct sched_domain *sd;
  5554. sd = &per_cpu(phys_domains, j).sd;
  5555. if (j != group_first_cpu(sd->groups)) {
  5556. /*
  5557. * Only add "power" once for each
  5558. * physical package.
  5559. */
  5560. continue;
  5561. }
  5562. sg->cpu_power += sd->groups->cpu_power;
  5563. }
  5564. sg = sg->next;
  5565. } while (sg != group_head);
  5566. }
  5567. static int build_numa_sched_groups(struct s_data *d,
  5568. const struct cpumask *cpu_map, int num)
  5569. {
  5570. struct sched_domain *sd;
  5571. struct sched_group *sg, *prev;
  5572. int n, j;
  5573. cpumask_clear(d->covered);
  5574. cpumask_and(d->nodemask, cpumask_of_node(num), cpu_map);
  5575. if (cpumask_empty(d->nodemask)) {
  5576. d->sched_group_nodes[num] = NULL;
  5577. goto out;
  5578. }
  5579. sched_domain_node_span(num, d->domainspan);
  5580. cpumask_and(d->domainspan, d->domainspan, cpu_map);
  5581. sg = kmalloc_node(sizeof(struct sched_group) + cpumask_size(),
  5582. GFP_KERNEL, num);
  5583. if (!sg) {
  5584. printk(KERN_WARNING "Can not alloc domain group for node %d\n",
  5585. num);
  5586. return -ENOMEM;
  5587. }
  5588. d->sched_group_nodes[num] = sg;
  5589. for_each_cpu(j, d->nodemask) {
  5590. sd = &per_cpu(node_domains, j).sd;
  5591. sd->groups = sg;
  5592. }
  5593. sg->cpu_power = 0;
  5594. cpumask_copy(sched_group_cpus(sg), d->nodemask);
  5595. sg->next = sg;
  5596. cpumask_or(d->covered, d->covered, d->nodemask);
  5597. prev = sg;
  5598. for (j = 0; j < nr_node_ids; j++) {
  5599. n = (num + j) % nr_node_ids;
  5600. cpumask_complement(d->notcovered, d->covered);
  5601. cpumask_and(d->tmpmask, d->notcovered, cpu_map);
  5602. cpumask_and(d->tmpmask, d->tmpmask, d->domainspan);
  5603. if (cpumask_empty(d->tmpmask))
  5604. break;
  5605. cpumask_and(d->tmpmask, d->tmpmask, cpumask_of_node(n));
  5606. if (cpumask_empty(d->tmpmask))
  5607. continue;
  5608. sg = kmalloc_node(sizeof(struct sched_group) + cpumask_size(),
  5609. GFP_KERNEL, num);
  5610. if (!sg) {
  5611. printk(KERN_WARNING
  5612. "Can not alloc domain group for node %d\n", j);
  5613. return -ENOMEM;
  5614. }
  5615. sg->cpu_power = 0;
  5616. cpumask_copy(sched_group_cpus(sg), d->tmpmask);
  5617. sg->next = prev->next;
  5618. cpumask_or(d->covered, d->covered, d->tmpmask);
  5619. prev->next = sg;
  5620. prev = sg;
  5621. }
  5622. out:
  5623. return 0;
  5624. }
  5625. #endif /* CONFIG_NUMA */
  5626. #ifdef CONFIG_NUMA
  5627. /* Free memory allocated for various sched_group structures */
  5628. static void free_sched_groups(const struct cpumask *cpu_map,
  5629. struct cpumask *nodemask)
  5630. {
  5631. int cpu, i;
  5632. for_each_cpu(cpu, cpu_map) {
  5633. struct sched_group **sched_group_nodes
  5634. = sched_group_nodes_bycpu[cpu];
  5635. if (!sched_group_nodes)
  5636. continue;
  5637. for (i = 0; i < nr_node_ids; i++) {
  5638. struct sched_group *oldsg, *sg = sched_group_nodes[i];
  5639. cpumask_and(nodemask, cpumask_of_node(i), cpu_map);
  5640. if (cpumask_empty(nodemask))
  5641. continue;
  5642. if (sg == NULL)
  5643. continue;
  5644. sg = sg->next;
  5645. next_sg:
  5646. oldsg = sg;
  5647. sg = sg->next;
  5648. kfree(oldsg);
  5649. if (oldsg != sched_group_nodes[i])
  5650. goto next_sg;
  5651. }
  5652. kfree(sched_group_nodes);
  5653. sched_group_nodes_bycpu[cpu] = NULL;
  5654. }
  5655. }
  5656. #else /* !CONFIG_NUMA */
  5657. static void free_sched_groups(const struct cpumask *cpu_map,
  5658. struct cpumask *nodemask)
  5659. {
  5660. }
  5661. #endif /* CONFIG_NUMA */
  5662. /*
  5663. * Initialize sched groups cpu_power.
  5664. *
  5665. * cpu_power indicates the capacity of sched group, which is used while
  5666. * distributing the load between different sched groups in a sched domain.
  5667. * Typically cpu_power for all the groups in a sched domain will be same unless
  5668. * there are asymmetries in the topology. If there are asymmetries, group
  5669. * having more cpu_power will pickup more load compared to the group having
  5670. * less cpu_power.
  5671. */
  5672. static void init_sched_groups_power(int cpu, struct sched_domain *sd)
  5673. {
  5674. struct sched_domain *child;
  5675. struct sched_group *group;
  5676. long power;
  5677. int weight;
  5678. WARN_ON(!sd || !sd->groups);
  5679. if (cpu != group_first_cpu(sd->groups))
  5680. return;
  5681. child = sd->child;
  5682. sd->groups->cpu_power = 0;
  5683. if (!child) {
  5684. power = SCHED_LOAD_SCALE;
  5685. weight = cpumask_weight(sched_domain_span(sd));
  5686. /*
  5687. * SMT siblings share the power of a single core.
  5688. * Usually multiple threads get a better yield out of
  5689. * that one core than a single thread would have,
  5690. * reflect that in sd->smt_gain.
  5691. */
  5692. if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) {
  5693. power *= sd->smt_gain;
  5694. power /= weight;
  5695. power >>= SCHED_LOAD_SHIFT;
  5696. }
  5697. sd->groups->cpu_power += power;
  5698. return;
  5699. }
  5700. /*
  5701. * Add cpu_power of each child group to this groups cpu_power.
  5702. */
  5703. group = child->groups;
  5704. do {
  5705. sd->groups->cpu_power += group->cpu_power;
  5706. group = group->next;
  5707. } while (group != child->groups);
  5708. }
  5709. /*
  5710. * Initializers for schedule domains
  5711. * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
  5712. */
  5713. #ifdef CONFIG_SCHED_DEBUG
  5714. # define SD_INIT_NAME(sd, type) sd->name = #type
  5715. #else
  5716. # define SD_INIT_NAME(sd, type) do { } while (0)
  5717. #endif
  5718. #define SD_INIT(sd, type) sd_init_##type(sd)
  5719. #define SD_INIT_FUNC(type) \
  5720. static noinline void sd_init_##type(struct sched_domain *sd) \
  5721. { \
  5722. memset(sd, 0, sizeof(*sd)); \
  5723. *sd = SD_##type##_INIT; \
  5724. sd->level = SD_LV_##type; \
  5725. SD_INIT_NAME(sd, type); \
  5726. }
  5727. SD_INIT_FUNC(CPU)
  5728. #ifdef CONFIG_NUMA
  5729. SD_INIT_FUNC(ALLNODES)
  5730. SD_INIT_FUNC(NODE)
  5731. #endif
  5732. #ifdef CONFIG_SCHED_SMT
  5733. SD_INIT_FUNC(SIBLING)
  5734. #endif
  5735. #ifdef CONFIG_SCHED_MC
  5736. SD_INIT_FUNC(MC)
  5737. #endif
  5738. static int default_relax_domain_level = -1;
  5739. static int __init setup_relax_domain_level(char *str)
  5740. {
  5741. unsigned long val;
  5742. val = simple_strtoul(str, NULL, 0);
  5743. if (val < SD_LV_MAX)
  5744. default_relax_domain_level = val;
  5745. return 1;
  5746. }
  5747. __setup("relax_domain_level=", setup_relax_domain_level);
  5748. static void set_domain_attribute(struct sched_domain *sd,
  5749. struct sched_domain_attr *attr)
  5750. {
  5751. int request;
  5752. if (!attr || attr->relax_domain_level < 0) {
  5753. if (default_relax_domain_level < 0)
  5754. return;
  5755. else
  5756. request = default_relax_domain_level;
  5757. } else
  5758. request = attr->relax_domain_level;
  5759. if (request < sd->level) {
  5760. /* turn off idle balance on this domain */
  5761. sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
  5762. } else {
  5763. /* turn on idle balance on this domain */
  5764. sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
  5765. }
  5766. }
  5767. static void __free_domain_allocs(struct s_data *d, enum s_alloc what,
  5768. const struct cpumask *cpu_map)
  5769. {
  5770. switch (what) {
  5771. case sa_sched_groups:
  5772. free_sched_groups(cpu_map, d->tmpmask); /* fall through */
  5773. d->sched_group_nodes = NULL;
  5774. case sa_rootdomain:
  5775. free_rootdomain(d->rd); /* fall through */
  5776. case sa_tmpmask:
  5777. free_cpumask_var(d->tmpmask); /* fall through */
  5778. case sa_send_covered:
  5779. free_cpumask_var(d->send_covered); /* fall through */
  5780. case sa_this_core_map:
  5781. free_cpumask_var(d->this_core_map); /* fall through */
  5782. case sa_this_sibling_map:
  5783. free_cpumask_var(d->this_sibling_map); /* fall through */
  5784. case sa_nodemask:
  5785. free_cpumask_var(d->nodemask); /* fall through */
  5786. case sa_sched_group_nodes:
  5787. #ifdef CONFIG_NUMA
  5788. kfree(d->sched_group_nodes); /* fall through */
  5789. case sa_notcovered:
  5790. free_cpumask_var(d->notcovered); /* fall through */
  5791. case sa_covered:
  5792. free_cpumask_var(d->covered); /* fall through */
  5793. case sa_domainspan:
  5794. free_cpumask_var(d->domainspan); /* fall through */
  5795. #endif
  5796. case sa_none:
  5797. break;
  5798. }
  5799. }
  5800. static enum s_alloc __visit_domain_allocation_hell(struct s_data *d,
  5801. const struct cpumask *cpu_map)
  5802. {
  5803. #ifdef CONFIG_NUMA
  5804. if (!alloc_cpumask_var(&d->domainspan, GFP_KERNEL))
  5805. return sa_none;
  5806. if (!alloc_cpumask_var(&d->covered, GFP_KERNEL))
  5807. return sa_domainspan;
  5808. if (!alloc_cpumask_var(&d->notcovered, GFP_KERNEL))
  5809. return sa_covered;
  5810. /* Allocate the per-node list of sched groups */
  5811. d->sched_group_nodes = kcalloc(nr_node_ids,
  5812. sizeof(struct sched_group *), GFP_KERNEL);
  5813. if (!d->sched_group_nodes) {
  5814. printk(KERN_WARNING "Can not alloc sched group node list\n");
  5815. return sa_notcovered;
  5816. }
  5817. sched_group_nodes_bycpu[cpumask_first(cpu_map)] = d->sched_group_nodes;
  5818. #endif
  5819. if (!alloc_cpumask_var(&d->nodemask, GFP_KERNEL))
  5820. return sa_sched_group_nodes;
  5821. if (!alloc_cpumask_var(&d->this_sibling_map, GFP_KERNEL))
  5822. return sa_nodemask;
  5823. if (!alloc_cpumask_var(&d->this_core_map, GFP_KERNEL))
  5824. return sa_this_sibling_map;
  5825. if (!alloc_cpumask_var(&d->send_covered, GFP_KERNEL))
  5826. return sa_this_core_map;
  5827. if (!alloc_cpumask_var(&d->tmpmask, GFP_KERNEL))
  5828. return sa_send_covered;
  5829. d->rd = alloc_rootdomain();
  5830. if (!d->rd) {
  5831. printk(KERN_WARNING "Cannot alloc root domain\n");
  5832. return sa_tmpmask;
  5833. }
  5834. return sa_rootdomain;
  5835. }
  5836. static struct sched_domain *__build_numa_sched_domains(struct s_data *d,
  5837. const struct cpumask *cpu_map, struct sched_domain_attr *attr, int i)
  5838. {
  5839. struct sched_domain *sd = NULL;
  5840. #ifdef CONFIG_NUMA
  5841. struct sched_domain *parent;
  5842. d->sd_allnodes = 0;
  5843. if (cpumask_weight(cpu_map) >
  5844. SD_NODES_PER_DOMAIN * cpumask_weight(d->nodemask)) {
  5845. sd = &per_cpu(allnodes_domains, i).sd;
  5846. SD_INIT(sd, ALLNODES);
  5847. set_domain_attribute(sd, attr);
  5848. cpumask_copy(sched_domain_span(sd), cpu_map);
  5849. cpu_to_allnodes_group(i, cpu_map, &sd->groups, d->tmpmask);
  5850. d->sd_allnodes = 1;
  5851. }
  5852. parent = sd;
  5853. sd = &per_cpu(node_domains, i).sd;
  5854. SD_INIT(sd, NODE);
  5855. set_domain_attribute(sd, attr);
  5856. sched_domain_node_span(cpu_to_node(i), sched_domain_span(sd));
  5857. sd->parent = parent;
  5858. if (parent)
  5859. parent->child = sd;
  5860. cpumask_and(sched_domain_span(sd), sched_domain_span(sd), cpu_map);
  5861. #endif
  5862. return sd;
  5863. }
  5864. static struct sched_domain *__build_cpu_sched_domain(struct s_data *d,
  5865. const struct cpumask *cpu_map, struct sched_domain_attr *attr,
  5866. struct sched_domain *parent, int i)
  5867. {
  5868. struct sched_domain *sd;
  5869. sd = &per_cpu(phys_domains, i).sd;
  5870. SD_INIT(sd, CPU);
  5871. set_domain_attribute(sd, attr);
  5872. cpumask_copy(sched_domain_span(sd), d->nodemask);
  5873. sd->parent = parent;
  5874. if (parent)
  5875. parent->child = sd;
  5876. cpu_to_phys_group(i, cpu_map, &sd->groups, d->tmpmask);
  5877. return sd;
  5878. }
  5879. static struct sched_domain *__build_mc_sched_domain(struct s_data *d,
  5880. const struct cpumask *cpu_map, struct sched_domain_attr *attr,
  5881. struct sched_domain *parent, int i)
  5882. {
  5883. struct sched_domain *sd = parent;
  5884. #ifdef CONFIG_SCHED_MC
  5885. sd = &per_cpu(core_domains, i).sd;
  5886. SD_INIT(sd, MC);
  5887. set_domain_attribute(sd, attr);
  5888. cpumask_and(sched_domain_span(sd), cpu_map, cpu_coregroup_mask(i));
  5889. sd->parent = parent;
  5890. parent->child = sd;
  5891. cpu_to_core_group(i, cpu_map, &sd->groups, d->tmpmask);
  5892. #endif
  5893. return sd;
  5894. }
  5895. static struct sched_domain *__build_smt_sched_domain(struct s_data *d,
  5896. const struct cpumask *cpu_map, struct sched_domain_attr *attr,
  5897. struct sched_domain *parent, int i)
  5898. {
  5899. struct sched_domain *sd = parent;
  5900. #ifdef CONFIG_SCHED_SMT
  5901. sd = &per_cpu(cpu_domains, i).sd;
  5902. SD_INIT(sd, SIBLING);
  5903. set_domain_attribute(sd, attr);
  5904. cpumask_and(sched_domain_span(sd), cpu_map, topology_thread_cpumask(i));
  5905. sd->parent = parent;
  5906. parent->child = sd;
  5907. cpu_to_cpu_group(i, cpu_map, &sd->groups, d->tmpmask);
  5908. #endif
  5909. return sd;
  5910. }
  5911. static void build_sched_groups(struct s_data *d, enum sched_domain_level l,
  5912. const struct cpumask *cpu_map, int cpu)
  5913. {
  5914. switch (l) {
  5915. #ifdef CONFIG_SCHED_SMT
  5916. case SD_LV_SIBLING: /* set up CPU (sibling) groups */
  5917. cpumask_and(d->this_sibling_map, cpu_map,
  5918. topology_thread_cpumask(cpu));
  5919. if (cpu == cpumask_first(d->this_sibling_map))
  5920. init_sched_build_groups(d->this_sibling_map, cpu_map,
  5921. &cpu_to_cpu_group,
  5922. d->send_covered, d->tmpmask);
  5923. break;
  5924. #endif
  5925. #ifdef CONFIG_SCHED_MC
  5926. case SD_LV_MC: /* set up multi-core groups */
  5927. cpumask_and(d->this_core_map, cpu_map, cpu_coregroup_mask(cpu));
  5928. if (cpu == cpumask_first(d->this_core_map))
  5929. init_sched_build_groups(d->this_core_map, cpu_map,
  5930. &cpu_to_core_group,
  5931. d->send_covered, d->tmpmask);
  5932. break;
  5933. #endif
  5934. case SD_LV_CPU: /* set up physical groups */
  5935. cpumask_and(d->nodemask, cpumask_of_node(cpu), cpu_map);
  5936. if (!cpumask_empty(d->nodemask))
  5937. init_sched_build_groups(d->nodemask, cpu_map,
  5938. &cpu_to_phys_group,
  5939. d->send_covered, d->tmpmask);
  5940. break;
  5941. #ifdef CONFIG_NUMA
  5942. case SD_LV_ALLNODES:
  5943. init_sched_build_groups(cpu_map, cpu_map, &cpu_to_allnodes_group,
  5944. d->send_covered, d->tmpmask);
  5945. break;
  5946. #endif
  5947. default:
  5948. break;
  5949. }
  5950. }
  5951. /*
  5952. * Build sched domains for a given set of cpus and attach the sched domains
  5953. * to the individual cpus
  5954. */
  5955. static int __build_sched_domains(const struct cpumask *cpu_map,
  5956. struct sched_domain_attr *attr)
  5957. {
  5958. enum s_alloc alloc_state = sa_none;
  5959. struct s_data d;
  5960. struct sched_domain *sd;
  5961. int i;
  5962. #ifdef CONFIG_NUMA
  5963. d.sd_allnodes = 0;
  5964. #endif
  5965. alloc_state = __visit_domain_allocation_hell(&d, cpu_map);
  5966. if (alloc_state != sa_rootdomain)
  5967. goto error;
  5968. alloc_state = sa_sched_groups;
  5969. /*
  5970. * Set up domains for cpus specified by the cpu_map.
  5971. */
  5972. for_each_cpu(i, cpu_map) {
  5973. cpumask_and(d.nodemask, cpumask_of_node(cpu_to_node(i)),
  5974. cpu_map);
  5975. sd = __build_numa_sched_domains(&d, cpu_map, attr, i);
  5976. sd = __build_cpu_sched_domain(&d, cpu_map, attr, sd, i);
  5977. sd = __build_mc_sched_domain(&d, cpu_map, attr, sd, i);
  5978. sd = __build_smt_sched_domain(&d, cpu_map, attr, sd, i);
  5979. }
  5980. for_each_cpu(i, cpu_map) {
  5981. build_sched_groups(&d, SD_LV_SIBLING, cpu_map, i);
  5982. build_sched_groups(&d, SD_LV_MC, cpu_map, i);
  5983. }
  5984. /* Set up physical groups */
  5985. for (i = 0; i < nr_node_ids; i++)
  5986. build_sched_groups(&d, SD_LV_CPU, cpu_map, i);
  5987. #ifdef CONFIG_NUMA
  5988. /* Set up node groups */
  5989. if (d.sd_allnodes)
  5990. build_sched_groups(&d, SD_LV_ALLNODES, cpu_map, 0);
  5991. for (i = 0; i < nr_node_ids; i++)
  5992. if (build_numa_sched_groups(&d, cpu_map, i))
  5993. goto error;
  5994. #endif
  5995. /* Calculate CPU power for physical packages and nodes */
  5996. #ifdef CONFIG_SCHED_SMT
  5997. for_each_cpu(i, cpu_map) {
  5998. sd = &per_cpu(cpu_domains, i).sd;
  5999. init_sched_groups_power(i, sd);
  6000. }
  6001. #endif
  6002. #ifdef CONFIG_SCHED_MC
  6003. for_each_cpu(i, cpu_map) {
  6004. sd = &per_cpu(core_domains, i).sd;
  6005. init_sched_groups_power(i, sd);
  6006. }
  6007. #endif
  6008. for_each_cpu(i, cpu_map) {
  6009. sd = &per_cpu(phys_domains, i).sd;
  6010. init_sched_groups_power(i, sd);
  6011. }
  6012. #ifdef CONFIG_NUMA
  6013. for (i = 0; i < nr_node_ids; i++)
  6014. init_numa_sched_groups_power(d.sched_group_nodes[i]);
  6015. if (d.sd_allnodes) {
  6016. struct sched_group *sg;
  6017. cpu_to_allnodes_group(cpumask_first(cpu_map), cpu_map, &sg,
  6018. d.tmpmask);
  6019. init_numa_sched_groups_power(sg);
  6020. }
  6021. #endif
  6022. /* Attach the domains */
  6023. for_each_cpu(i, cpu_map) {
  6024. #ifdef CONFIG_SCHED_SMT
  6025. sd = &per_cpu(cpu_domains, i).sd;
  6026. #elif defined(CONFIG_SCHED_MC)
  6027. sd = &per_cpu(core_domains, i).sd;
  6028. #else
  6029. sd = &per_cpu(phys_domains, i).sd;
  6030. #endif
  6031. cpu_attach_domain(sd, d.rd, i);
  6032. }
  6033. d.sched_group_nodes = NULL; /* don't free this we still need it */
  6034. __free_domain_allocs(&d, sa_tmpmask, cpu_map);
  6035. return 0;
  6036. error:
  6037. __free_domain_allocs(&d, alloc_state, cpu_map);
  6038. return -ENOMEM;
  6039. }
  6040. static int build_sched_domains(const struct cpumask *cpu_map)
  6041. {
  6042. return __build_sched_domains(cpu_map, NULL);
  6043. }
  6044. static cpumask_var_t *doms_cur; /* current sched domains */
  6045. static int ndoms_cur; /* number of sched domains in 'doms_cur' */
  6046. static struct sched_domain_attr *dattr_cur;
  6047. /* attribues of custom domains in 'doms_cur' */
  6048. /*
  6049. * Special case: If a kmalloc of a doms_cur partition (array of
  6050. * cpumask) fails, then fallback to a single sched domain,
  6051. * as determined by the single cpumask fallback_doms.
  6052. */
  6053. static cpumask_var_t fallback_doms;
  6054. /*
  6055. * arch_update_cpu_topology lets virtualized architectures update the
  6056. * cpu core maps. It is supposed to return 1 if the topology changed
  6057. * or 0 if it stayed the same.
  6058. */
  6059. int __attribute__((weak)) arch_update_cpu_topology(void)
  6060. {
  6061. return 0;
  6062. }
  6063. cpumask_var_t *alloc_sched_domains(unsigned int ndoms)
  6064. {
  6065. int i;
  6066. cpumask_var_t *doms;
  6067. doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL);
  6068. if (!doms)
  6069. return NULL;
  6070. for (i = 0; i < ndoms; i++) {
  6071. if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) {
  6072. free_sched_domains(doms, i);
  6073. return NULL;
  6074. }
  6075. }
  6076. return doms;
  6077. }
  6078. void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms)
  6079. {
  6080. unsigned int i;
  6081. for (i = 0; i < ndoms; i++)
  6082. free_cpumask_var(doms[i]);
  6083. kfree(doms);
  6084. }
  6085. /*
  6086. * Set up scheduler domains and groups. Callers must hold the hotplug lock.
  6087. * For now this just excludes isolated cpus, but could be used to
  6088. * exclude other special cases in the future.
  6089. */
  6090. static int arch_init_sched_domains(const struct cpumask *cpu_map)
  6091. {
  6092. int err;
  6093. arch_update_cpu_topology();
  6094. ndoms_cur = 1;
  6095. doms_cur = alloc_sched_domains(ndoms_cur);
  6096. if (!doms_cur)
  6097. doms_cur = &fallback_doms;
  6098. cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map);
  6099. dattr_cur = NULL;
  6100. err = build_sched_domains(doms_cur[0]);
  6101. register_sched_domain_sysctl();
  6102. return err;
  6103. }
  6104. static void arch_destroy_sched_domains(const struct cpumask *cpu_map,
  6105. struct cpumask *tmpmask)
  6106. {
  6107. free_sched_groups(cpu_map, tmpmask);
  6108. }
  6109. /*
  6110. * Detach sched domains from a group of cpus specified in cpu_map
  6111. * These cpus will now be attached to the NULL domain
  6112. */
  6113. static void detach_destroy_domains(const struct cpumask *cpu_map)
  6114. {
  6115. /* Save because hotplug lock held. */
  6116. static DECLARE_BITMAP(tmpmask, CONFIG_NR_CPUS);
  6117. int i;
  6118. for_each_cpu(i, cpu_map)
  6119. cpu_attach_domain(NULL, &def_root_domain, i);
  6120. synchronize_sched();
  6121. arch_destroy_sched_domains(cpu_map, to_cpumask(tmpmask));
  6122. }
  6123. /* handle null as "default" */
  6124. static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
  6125. struct sched_domain_attr *new, int idx_new)
  6126. {
  6127. struct sched_domain_attr tmp;
  6128. /* fast path */
  6129. if (!new && !cur)
  6130. return 1;
  6131. tmp = SD_ATTR_INIT;
  6132. return !memcmp(cur ? (cur + idx_cur) : &tmp,
  6133. new ? (new + idx_new) : &tmp,
  6134. sizeof(struct sched_domain_attr));
  6135. }
  6136. /*
  6137. * Partition sched domains as specified by the 'ndoms_new'
  6138. * cpumasks in the array doms_new[] of cpumasks. This compares
  6139. * doms_new[] to the current sched domain partitioning, doms_cur[].
  6140. * It destroys each deleted domain and builds each new domain.
  6141. *
  6142. * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
  6143. * The masks don't intersect (don't overlap.) We should setup one
  6144. * sched domain for each mask. CPUs not in any of the cpumasks will
  6145. * not be load balanced. If the same cpumask appears both in the
  6146. * current 'doms_cur' domains and in the new 'doms_new', we can leave
  6147. * it as it is.
  6148. *
  6149. * The passed in 'doms_new' should be allocated using
  6150. * alloc_sched_domains. This routine takes ownership of it and will
  6151. * free_sched_domains it when done with it. If the caller failed the
  6152. * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
  6153. * and partition_sched_domains() will fallback to the single partition
  6154. * 'fallback_doms', it also forces the domains to be rebuilt.
  6155. *
  6156. * If doms_new == NULL it will be replaced with cpu_online_mask.
  6157. * ndoms_new == 0 is a special case for destroying existing domains,
  6158. * and it will not create the default domain.
  6159. *
  6160. * Call with hotplug lock held
  6161. */
  6162. void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
  6163. struct sched_domain_attr *dattr_new)
  6164. {
  6165. int i, j, n;
  6166. int new_topology;
  6167. mutex_lock(&sched_domains_mutex);
  6168. /* always unregister in case we don't destroy any domains */
  6169. unregister_sched_domain_sysctl();
  6170. /* Let architecture update cpu core mappings. */
  6171. new_topology = arch_update_cpu_topology();
  6172. n = doms_new ? ndoms_new : 0;
  6173. /* Destroy deleted domains */
  6174. for (i = 0; i < ndoms_cur; i++) {
  6175. for (j = 0; j < n && !new_topology; j++) {
  6176. if (cpumask_equal(doms_cur[i], doms_new[j])
  6177. && dattrs_equal(dattr_cur, i, dattr_new, j))
  6178. goto match1;
  6179. }
  6180. /* no match - a current sched domain not in new doms_new[] */
  6181. detach_destroy_domains(doms_cur[i]);
  6182. match1:
  6183. ;
  6184. }
  6185. if (doms_new == NULL) {
  6186. ndoms_cur = 0;
  6187. doms_new = &fallback_doms;
  6188. cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map);
  6189. WARN_ON_ONCE(dattr_new);
  6190. }
  6191. /* Build new domains */
  6192. for (i = 0; i < ndoms_new; i++) {
  6193. for (j = 0; j < ndoms_cur && !new_topology; j++) {
  6194. if (cpumask_equal(doms_new[i], doms_cur[j])
  6195. && dattrs_equal(dattr_new, i, dattr_cur, j))
  6196. goto match2;
  6197. }
  6198. /* no match - add a new doms_new */
  6199. __build_sched_domains(doms_new[i],
  6200. dattr_new ? dattr_new + i : NULL);
  6201. match2:
  6202. ;
  6203. }
  6204. /* Remember the new sched domains */
  6205. if (doms_cur != &fallback_doms)
  6206. free_sched_domains(doms_cur, ndoms_cur);
  6207. kfree(dattr_cur); /* kfree(NULL) is safe */
  6208. doms_cur = doms_new;
  6209. dattr_cur = dattr_new;
  6210. ndoms_cur = ndoms_new;
  6211. register_sched_domain_sysctl();
  6212. mutex_unlock(&sched_domains_mutex);
  6213. }
  6214. #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
  6215. static void arch_reinit_sched_domains(void)
  6216. {
  6217. get_online_cpus();
  6218. /* Destroy domains first to force the rebuild */
  6219. partition_sched_domains(0, NULL, NULL);
  6220. rebuild_sched_domains();
  6221. put_online_cpus();
  6222. }
  6223. static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt)
  6224. {
  6225. unsigned int level = 0;
  6226. if (sscanf(buf, "%u", &level) != 1)
  6227. return -EINVAL;
  6228. /*
  6229. * level is always be positive so don't check for
  6230. * level < POWERSAVINGS_BALANCE_NONE which is 0
  6231. * What happens on 0 or 1 byte write,
  6232. * need to check for count as well?
  6233. */
  6234. if (level >= MAX_POWERSAVINGS_BALANCE_LEVELS)
  6235. return -EINVAL;
  6236. if (smt)
  6237. sched_smt_power_savings = level;
  6238. else
  6239. sched_mc_power_savings = level;
  6240. arch_reinit_sched_domains();
  6241. return count;
  6242. }
  6243. #ifdef CONFIG_SCHED_MC
  6244. static ssize_t sched_mc_power_savings_show(struct sysdev_class *class,
  6245. char *page)
  6246. {
  6247. return sprintf(page, "%u\n", sched_mc_power_savings);
  6248. }
  6249. static ssize_t sched_mc_power_savings_store(struct sysdev_class *class,
  6250. const char *buf, size_t count)
  6251. {
  6252. return sched_power_savings_store(buf, count, 0);
  6253. }
  6254. static SYSDEV_CLASS_ATTR(sched_mc_power_savings, 0644,
  6255. sched_mc_power_savings_show,
  6256. sched_mc_power_savings_store);
  6257. #endif
  6258. #ifdef CONFIG_SCHED_SMT
  6259. static ssize_t sched_smt_power_savings_show(struct sysdev_class *dev,
  6260. char *page)
  6261. {
  6262. return sprintf(page, "%u\n", sched_smt_power_savings);
  6263. }
  6264. static ssize_t sched_smt_power_savings_store(struct sysdev_class *dev,
  6265. const char *buf, size_t count)
  6266. {
  6267. return sched_power_savings_store(buf, count, 1);
  6268. }
  6269. static SYSDEV_CLASS_ATTR(sched_smt_power_savings, 0644,
  6270. sched_smt_power_savings_show,
  6271. sched_smt_power_savings_store);
  6272. #endif
  6273. int __init sched_create_sysfs_power_savings_entries(struct sysdev_class *cls)
  6274. {
  6275. int err = 0;
  6276. #ifdef CONFIG_SCHED_SMT
  6277. if (smt_capable())
  6278. err = sysfs_create_file(&cls->kset.kobj,
  6279. &attr_sched_smt_power_savings.attr);
  6280. #endif
  6281. #ifdef CONFIG_SCHED_MC
  6282. if (!err && mc_capable())
  6283. err = sysfs_create_file(&cls->kset.kobj,
  6284. &attr_sched_mc_power_savings.attr);
  6285. #endif
  6286. return err;
  6287. }
  6288. #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
  6289. #ifndef CONFIG_CPUSETS
  6290. /*
  6291. * Add online and remove offline CPUs from the scheduler domains.
  6292. * When cpusets are enabled they take over this function.
  6293. */
  6294. static int update_sched_domains(struct notifier_block *nfb,
  6295. unsigned long action, void *hcpu)
  6296. {
  6297. switch (action) {
  6298. case CPU_ONLINE:
  6299. case CPU_ONLINE_FROZEN:
  6300. case CPU_DOWN_PREPARE:
  6301. case CPU_DOWN_PREPARE_FROZEN:
  6302. case CPU_DOWN_FAILED:
  6303. case CPU_DOWN_FAILED_FROZEN:
  6304. partition_sched_domains(1, NULL, NULL);
  6305. return NOTIFY_OK;
  6306. default:
  6307. return NOTIFY_DONE;
  6308. }
  6309. }
  6310. #endif
  6311. static int update_runtime(struct notifier_block *nfb,
  6312. unsigned long action, void *hcpu)
  6313. {
  6314. int cpu = (int)(long)hcpu;
  6315. switch (action) {
  6316. case CPU_DOWN_PREPARE:
  6317. case CPU_DOWN_PREPARE_FROZEN:
  6318. disable_runtime(cpu_rq(cpu));
  6319. return NOTIFY_OK;
  6320. case CPU_DOWN_FAILED:
  6321. case CPU_DOWN_FAILED_FROZEN:
  6322. case CPU_ONLINE:
  6323. case CPU_ONLINE_FROZEN:
  6324. enable_runtime(cpu_rq(cpu));
  6325. return NOTIFY_OK;
  6326. default:
  6327. return NOTIFY_DONE;
  6328. }
  6329. }
  6330. void __init sched_init_smp(void)
  6331. {
  6332. cpumask_var_t non_isolated_cpus;
  6333. alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL);
  6334. alloc_cpumask_var(&fallback_doms, GFP_KERNEL);
  6335. #if defined(CONFIG_NUMA)
  6336. sched_group_nodes_bycpu = kzalloc(nr_cpu_ids * sizeof(void **),
  6337. GFP_KERNEL);
  6338. BUG_ON(sched_group_nodes_bycpu == NULL);
  6339. #endif
  6340. get_online_cpus();
  6341. mutex_lock(&sched_domains_mutex);
  6342. arch_init_sched_domains(cpu_active_mask);
  6343. cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map);
  6344. if (cpumask_empty(non_isolated_cpus))
  6345. cpumask_set_cpu(smp_processor_id(), non_isolated_cpus);
  6346. mutex_unlock(&sched_domains_mutex);
  6347. put_online_cpus();
  6348. #ifndef CONFIG_CPUSETS
  6349. /* XXX: Theoretical race here - CPU may be hotplugged now */
  6350. hotcpu_notifier(update_sched_domains, 0);
  6351. #endif
  6352. /* RT runtime code needs to handle some hotplug events */
  6353. hotcpu_notifier(update_runtime, 0);
  6354. init_hrtick();
  6355. /* Move init over to a non-isolated CPU */
  6356. if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0)
  6357. BUG();
  6358. sched_init_granularity();
  6359. free_cpumask_var(non_isolated_cpus);
  6360. init_sched_rt_class();
  6361. }
  6362. #else
  6363. void __init sched_init_smp(void)
  6364. {
  6365. sched_init_granularity();
  6366. }
  6367. #endif /* CONFIG_SMP */
  6368. const_debug unsigned int sysctl_timer_migration = 1;
  6369. int in_sched_functions(unsigned long addr)
  6370. {
  6371. return in_lock_functions(addr) ||
  6372. (addr >= (unsigned long)__sched_text_start
  6373. && addr < (unsigned long)__sched_text_end);
  6374. }
  6375. static void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq)
  6376. {
  6377. cfs_rq->tasks_timeline = RB_ROOT;
  6378. INIT_LIST_HEAD(&cfs_rq->tasks);
  6379. #ifdef CONFIG_FAIR_GROUP_SCHED
  6380. cfs_rq->rq = rq;
  6381. #endif
  6382. cfs_rq->min_vruntime = (u64)(-(1LL << 20));
  6383. }
  6384. static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
  6385. {
  6386. struct rt_prio_array *array;
  6387. int i;
  6388. array = &rt_rq->active;
  6389. for (i = 0; i < MAX_RT_PRIO; i++) {
  6390. INIT_LIST_HEAD(array->queue + i);
  6391. __clear_bit(i, array->bitmap);
  6392. }
  6393. /* delimiter for bitsearch: */
  6394. __set_bit(MAX_RT_PRIO, array->bitmap);
  6395. #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
  6396. rt_rq->highest_prio.curr = MAX_RT_PRIO;
  6397. #ifdef CONFIG_SMP
  6398. rt_rq->highest_prio.next = MAX_RT_PRIO;
  6399. #endif
  6400. #endif
  6401. #ifdef CONFIG_SMP
  6402. rt_rq->rt_nr_migratory = 0;
  6403. rt_rq->overloaded = 0;
  6404. plist_head_init_raw(&rt_rq->pushable_tasks, &rq->lock);
  6405. #endif
  6406. rt_rq->rt_time = 0;
  6407. rt_rq->rt_throttled = 0;
  6408. rt_rq->rt_runtime = 0;
  6409. raw_spin_lock_init(&rt_rq->rt_runtime_lock);
  6410. #ifdef CONFIG_RT_GROUP_SCHED
  6411. rt_rq->rt_nr_boosted = 0;
  6412. rt_rq->rq = rq;
  6413. #endif
  6414. }
  6415. #ifdef CONFIG_FAIR_GROUP_SCHED
  6416. static void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
  6417. struct sched_entity *se, int cpu, int add,
  6418. struct sched_entity *parent)
  6419. {
  6420. struct rq *rq = cpu_rq(cpu);
  6421. tg->cfs_rq[cpu] = cfs_rq;
  6422. init_cfs_rq(cfs_rq, rq);
  6423. cfs_rq->tg = tg;
  6424. if (add)
  6425. list_add(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list);
  6426. tg->se[cpu] = se;
  6427. /* se could be NULL for init_task_group */
  6428. if (!se)
  6429. return;
  6430. if (!parent)
  6431. se->cfs_rq = &rq->cfs;
  6432. else
  6433. se->cfs_rq = parent->my_q;
  6434. se->my_q = cfs_rq;
  6435. se->load.weight = tg->shares;
  6436. se->load.inv_weight = 0;
  6437. se->parent = parent;
  6438. }
  6439. #endif
  6440. #ifdef CONFIG_RT_GROUP_SCHED
  6441. static void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
  6442. struct sched_rt_entity *rt_se, int cpu, int add,
  6443. struct sched_rt_entity *parent)
  6444. {
  6445. struct rq *rq = cpu_rq(cpu);
  6446. tg->rt_rq[cpu] = rt_rq;
  6447. init_rt_rq(rt_rq, rq);
  6448. rt_rq->tg = tg;
  6449. rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime;
  6450. if (add)
  6451. list_add(&rt_rq->leaf_rt_rq_list, &rq->leaf_rt_rq_list);
  6452. tg->rt_se[cpu] = rt_se;
  6453. if (!rt_se)
  6454. return;
  6455. if (!parent)
  6456. rt_se->rt_rq = &rq->rt;
  6457. else
  6458. rt_se->rt_rq = parent->my_q;
  6459. rt_se->my_q = rt_rq;
  6460. rt_se->parent = parent;
  6461. INIT_LIST_HEAD(&rt_se->run_list);
  6462. }
  6463. #endif
  6464. void __init sched_init(void)
  6465. {
  6466. int i, j;
  6467. unsigned long alloc_size = 0, ptr;
  6468. #ifdef CONFIG_FAIR_GROUP_SCHED
  6469. alloc_size += 2 * nr_cpu_ids * sizeof(void **);
  6470. #endif
  6471. #ifdef CONFIG_RT_GROUP_SCHED
  6472. alloc_size += 2 * nr_cpu_ids * sizeof(void **);
  6473. #endif
  6474. #ifdef CONFIG_CPUMASK_OFFSTACK
  6475. alloc_size += num_possible_cpus() * cpumask_size();
  6476. #endif
  6477. if (alloc_size) {
  6478. ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT);
  6479. #ifdef CONFIG_FAIR_GROUP_SCHED
  6480. init_task_group.se = (struct sched_entity **)ptr;
  6481. ptr += nr_cpu_ids * sizeof(void **);
  6482. init_task_group.cfs_rq = (struct cfs_rq **)ptr;
  6483. ptr += nr_cpu_ids * sizeof(void **);
  6484. #endif /* CONFIG_FAIR_GROUP_SCHED */
  6485. #ifdef CONFIG_RT_GROUP_SCHED
  6486. init_task_group.rt_se = (struct sched_rt_entity **)ptr;
  6487. ptr += nr_cpu_ids * sizeof(void **);
  6488. init_task_group.rt_rq = (struct rt_rq **)ptr;
  6489. ptr += nr_cpu_ids * sizeof(void **);
  6490. #endif /* CONFIG_RT_GROUP_SCHED */
  6491. #ifdef CONFIG_CPUMASK_OFFSTACK
  6492. for_each_possible_cpu(i) {
  6493. per_cpu(load_balance_tmpmask, i) = (void *)ptr;
  6494. ptr += cpumask_size();
  6495. }
  6496. #endif /* CONFIG_CPUMASK_OFFSTACK */
  6497. }
  6498. #ifdef CONFIG_SMP
  6499. init_defrootdomain();
  6500. #endif
  6501. init_rt_bandwidth(&def_rt_bandwidth,
  6502. global_rt_period(), global_rt_runtime());
  6503. #ifdef CONFIG_RT_GROUP_SCHED
  6504. init_rt_bandwidth(&init_task_group.rt_bandwidth,
  6505. global_rt_period(), global_rt_runtime());
  6506. #endif /* CONFIG_RT_GROUP_SCHED */
  6507. #ifdef CONFIG_CGROUP_SCHED
  6508. list_add(&init_task_group.list, &task_groups);
  6509. INIT_LIST_HEAD(&init_task_group.children);
  6510. #endif /* CONFIG_CGROUP_SCHED */
  6511. #if defined CONFIG_FAIR_GROUP_SCHED && defined CONFIG_SMP
  6512. update_shares_data = __alloc_percpu(nr_cpu_ids * sizeof(unsigned long),
  6513. __alignof__(unsigned long));
  6514. #endif
  6515. for_each_possible_cpu(i) {
  6516. struct rq *rq;
  6517. rq = cpu_rq(i);
  6518. raw_spin_lock_init(&rq->lock);
  6519. rq->nr_running = 0;
  6520. rq->calc_load_active = 0;
  6521. rq->calc_load_update = jiffies + LOAD_FREQ;
  6522. init_cfs_rq(&rq->cfs, rq);
  6523. init_rt_rq(&rq->rt, rq);
  6524. #ifdef CONFIG_FAIR_GROUP_SCHED
  6525. init_task_group.shares = init_task_group_load;
  6526. INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
  6527. #ifdef CONFIG_CGROUP_SCHED
  6528. /*
  6529. * How much cpu bandwidth does init_task_group get?
  6530. *
  6531. * In case of task-groups formed thr' the cgroup filesystem, it
  6532. * gets 100% of the cpu resources in the system. This overall
  6533. * system cpu resource is divided among the tasks of
  6534. * init_task_group and its child task-groups in a fair manner,
  6535. * based on each entity's (task or task-group's) weight
  6536. * (se->load.weight).
  6537. *
  6538. * In other words, if init_task_group has 10 tasks of weight
  6539. * 1024) and two child groups A0 and A1 (of weight 1024 each),
  6540. * then A0's share of the cpu resource is:
  6541. *
  6542. * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
  6543. *
  6544. * We achieve this by letting init_task_group's tasks sit
  6545. * directly in rq->cfs (i.e init_task_group->se[] = NULL).
  6546. */
  6547. init_tg_cfs_entry(&init_task_group, &rq->cfs, NULL, i, 1, NULL);
  6548. #endif
  6549. #endif /* CONFIG_FAIR_GROUP_SCHED */
  6550. rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime;
  6551. #ifdef CONFIG_RT_GROUP_SCHED
  6552. INIT_LIST_HEAD(&rq->leaf_rt_rq_list);
  6553. #ifdef CONFIG_CGROUP_SCHED
  6554. init_tg_rt_entry(&init_task_group, &rq->rt, NULL, i, 1, NULL);
  6555. #endif
  6556. #endif
  6557. for (j = 0; j < CPU_LOAD_IDX_MAX; j++)
  6558. rq->cpu_load[j] = 0;
  6559. #ifdef CONFIG_SMP
  6560. rq->sd = NULL;
  6561. rq->rd = NULL;
  6562. rq->post_schedule = 0;
  6563. rq->active_balance = 0;
  6564. rq->next_balance = jiffies;
  6565. rq->push_cpu = 0;
  6566. rq->cpu = i;
  6567. rq->online = 0;
  6568. rq->migration_thread = NULL;
  6569. rq->idle_stamp = 0;
  6570. rq->avg_idle = 2*sysctl_sched_migration_cost;
  6571. INIT_LIST_HEAD(&rq->migration_queue);
  6572. rq_attach_root(rq, &def_root_domain);
  6573. #endif
  6574. init_rq_hrtick(rq);
  6575. atomic_set(&rq->nr_iowait, 0);
  6576. }
  6577. set_load_weight(&init_task);
  6578. #ifdef CONFIG_PREEMPT_NOTIFIERS
  6579. INIT_HLIST_HEAD(&init_task.preempt_notifiers);
  6580. #endif
  6581. #ifdef CONFIG_SMP
  6582. open_softirq(SCHED_SOFTIRQ, run_rebalance_domains);
  6583. #endif
  6584. #ifdef CONFIG_RT_MUTEXES
  6585. plist_head_init_raw(&init_task.pi_waiters, &init_task.pi_lock);
  6586. #endif
  6587. /*
  6588. * The boot idle thread does lazy MMU switching as well:
  6589. */
  6590. atomic_inc(&init_mm.mm_count);
  6591. enter_lazy_tlb(&init_mm, current);
  6592. /*
  6593. * Make us the idle thread. Technically, schedule() should not be
  6594. * called from this thread, however somewhere below it might be,
  6595. * but because we are the idle thread, we just pick up running again
  6596. * when this runqueue becomes "idle".
  6597. */
  6598. init_idle(current, smp_processor_id());
  6599. calc_load_update = jiffies + LOAD_FREQ;
  6600. /*
  6601. * During early bootup we pretend to be a normal task:
  6602. */
  6603. current->sched_class = &fair_sched_class;
  6604. /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */
  6605. zalloc_cpumask_var(&nohz_cpu_mask, GFP_NOWAIT);
  6606. #ifdef CONFIG_SMP
  6607. #ifdef CONFIG_NO_HZ
  6608. zalloc_cpumask_var(&nohz.cpu_mask, GFP_NOWAIT);
  6609. alloc_cpumask_var(&nohz.ilb_grp_nohz_mask, GFP_NOWAIT);
  6610. #endif
  6611. /* May be allocated at isolcpus cmdline parse time */
  6612. if (cpu_isolated_map == NULL)
  6613. zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
  6614. #endif /* SMP */
  6615. perf_event_init();
  6616. scheduler_running = 1;
  6617. }
  6618. #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
  6619. static inline int preempt_count_equals(int preempt_offset)
  6620. {
  6621. int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth();
  6622. return (nested == PREEMPT_INATOMIC_BASE + preempt_offset);
  6623. }
  6624. void __might_sleep(const char *file, int line, int preempt_offset)
  6625. {
  6626. #ifdef in_atomic
  6627. static unsigned long prev_jiffy; /* ratelimiting */
  6628. if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) ||
  6629. system_state != SYSTEM_RUNNING || oops_in_progress)
  6630. return;
  6631. if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
  6632. return;
  6633. prev_jiffy = jiffies;
  6634. printk(KERN_ERR
  6635. "BUG: sleeping function called from invalid context at %s:%d\n",
  6636. file, line);
  6637. printk(KERN_ERR
  6638. "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
  6639. in_atomic(), irqs_disabled(),
  6640. current->pid, current->comm);
  6641. debug_show_held_locks(current);
  6642. if (irqs_disabled())
  6643. print_irqtrace_events(current);
  6644. dump_stack();
  6645. #endif
  6646. }
  6647. EXPORT_SYMBOL(__might_sleep);
  6648. #endif
  6649. #ifdef CONFIG_MAGIC_SYSRQ
  6650. static void normalize_task(struct rq *rq, struct task_struct *p)
  6651. {
  6652. int on_rq;
  6653. update_rq_clock(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. update_rq_clock(rq);
  6951. running = task_current(rq, tsk);
  6952. on_rq = tsk->se.on_rq;
  6953. if (on_rq)
  6954. dequeue_task(rq, tsk, 0);
  6955. if (unlikely(running))
  6956. tsk->sched_class->put_prev_task(rq, tsk);
  6957. set_task_rq(tsk, task_cpu(tsk));
  6958. #ifdef CONFIG_FAIR_GROUP_SCHED
  6959. if (tsk->sched_class->moved_group)
  6960. tsk->sched_class->moved_group(tsk, on_rq);
  6961. #endif
  6962. if (unlikely(running))
  6963. tsk->sched_class->set_curr_task(rq);
  6964. if (on_rq)
  6965. enqueue_task(rq, tsk, 0, false);
  6966. task_rq_unlock(rq, &flags);
  6967. }
  6968. #endif /* CONFIG_CGROUP_SCHED */
  6969. #ifdef CONFIG_FAIR_GROUP_SCHED
  6970. static void __set_se_shares(struct sched_entity *se, unsigned long shares)
  6971. {
  6972. struct cfs_rq *cfs_rq = se->cfs_rq;
  6973. int on_rq;
  6974. on_rq = se->on_rq;
  6975. if (on_rq)
  6976. dequeue_entity(cfs_rq, se, 0);
  6977. se->load.weight = shares;
  6978. se->load.inv_weight = 0;
  6979. if (on_rq)
  6980. enqueue_entity(cfs_rq, se, 0);
  6981. }
  6982. static void set_se_shares(struct sched_entity *se, unsigned long shares)
  6983. {
  6984. struct cfs_rq *cfs_rq = se->cfs_rq;
  6985. struct rq *rq = cfs_rq->rq;
  6986. unsigned long flags;
  6987. raw_spin_lock_irqsave(&rq->lock, flags);
  6988. __set_se_shares(se, shares);
  6989. raw_spin_unlock_irqrestore(&rq->lock, flags);
  6990. }
  6991. static DEFINE_MUTEX(shares_mutex);
  6992. int sched_group_set_shares(struct task_group *tg, unsigned long shares)
  6993. {
  6994. int i;
  6995. unsigned long flags;
  6996. /*
  6997. * We can't change the weight of the root cgroup.
  6998. */
  6999. if (!tg->se[0])
  7000. return -EINVAL;
  7001. if (shares < MIN_SHARES)
  7002. shares = MIN_SHARES;
  7003. else if (shares > MAX_SHARES)
  7004. shares = MAX_SHARES;
  7005. mutex_lock(&shares_mutex);
  7006. if (tg->shares == shares)
  7007. goto done;
  7008. spin_lock_irqsave(&task_group_lock, flags);
  7009. for_each_possible_cpu(i)
  7010. unregister_fair_sched_group(tg, i);
  7011. list_del_rcu(&tg->siblings);
  7012. spin_unlock_irqrestore(&task_group_lock, flags);
  7013. /* wait for any ongoing reference to this group to finish */
  7014. synchronize_sched();
  7015. /*
  7016. * Now we are free to modify the group's share on each cpu
  7017. * w/o tripping rebalance_share or load_balance_fair.
  7018. */
  7019. tg->shares = shares;
  7020. for_each_possible_cpu(i) {
  7021. /*
  7022. * force a rebalance
  7023. */
  7024. cfs_rq_set_shares(tg->cfs_rq[i], 0);
  7025. set_se_shares(tg->se[i], shares);
  7026. }
  7027. /*
  7028. * Enable load balance activity on this group, by inserting it back on
  7029. * each cpu's rq->leaf_cfs_rq_list.
  7030. */
  7031. spin_lock_irqsave(&task_group_lock, flags);
  7032. for_each_possible_cpu(i)
  7033. register_fair_sched_group(tg, i);
  7034. list_add_rcu(&tg->siblings, &tg->parent->children);
  7035. spin_unlock_irqrestore(&task_group_lock, flags);
  7036. done:
  7037. mutex_unlock(&shares_mutex);
  7038. return 0;
  7039. }
  7040. unsigned long sched_group_shares(struct task_group *tg)
  7041. {
  7042. return tg->shares;
  7043. }
  7044. #endif
  7045. #ifdef CONFIG_RT_GROUP_SCHED
  7046. /*
  7047. * Ensure that the real time constraints are schedulable.
  7048. */
  7049. static DEFINE_MUTEX(rt_constraints_mutex);
  7050. static unsigned long to_ratio(u64 period, u64 runtime)
  7051. {
  7052. if (runtime == RUNTIME_INF)
  7053. return 1ULL << 20;
  7054. return div64_u64(runtime << 20, period);
  7055. }
  7056. /* Must be called with tasklist_lock held */
  7057. static inline int tg_has_rt_tasks(struct task_group *tg)
  7058. {
  7059. struct task_struct *g, *p;
  7060. do_each_thread(g, p) {
  7061. if (rt_task(p) && rt_rq_of_se(&p->rt)->tg == tg)
  7062. return 1;
  7063. } while_each_thread(g, p);
  7064. return 0;
  7065. }
  7066. struct rt_schedulable_data {
  7067. struct task_group *tg;
  7068. u64 rt_period;
  7069. u64 rt_runtime;
  7070. };
  7071. static int tg_schedulable(struct task_group *tg, void *data)
  7072. {
  7073. struct rt_schedulable_data *d = data;
  7074. struct task_group *child;
  7075. unsigned long total, sum = 0;
  7076. u64 period, runtime;
  7077. period = ktime_to_ns(tg->rt_bandwidth.rt_period);
  7078. runtime = tg->rt_bandwidth.rt_runtime;
  7079. if (tg == d->tg) {
  7080. period = d->rt_period;
  7081. runtime = d->rt_runtime;
  7082. }
  7083. /*
  7084. * Cannot have more runtime than the period.
  7085. */
  7086. if (runtime > period && runtime != RUNTIME_INF)
  7087. return -EINVAL;
  7088. /*
  7089. * Ensure we don't starve existing RT tasks.
  7090. */
  7091. if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg))
  7092. return -EBUSY;
  7093. total = to_ratio(period, runtime);
  7094. /*
  7095. * Nobody can have more than the global setting allows.
  7096. */
  7097. if (total > to_ratio(global_rt_period(), global_rt_runtime()))
  7098. return -EINVAL;
  7099. /*
  7100. * The sum of our children's runtime should not exceed our own.
  7101. */
  7102. list_for_each_entry_rcu(child, &tg->children, siblings) {
  7103. period = ktime_to_ns(child->rt_bandwidth.rt_period);
  7104. runtime = child->rt_bandwidth.rt_runtime;
  7105. if (child == d->tg) {
  7106. period = d->rt_period;
  7107. runtime = d->rt_runtime;
  7108. }
  7109. sum += to_ratio(period, runtime);
  7110. }
  7111. if (sum > total)
  7112. return -EINVAL;
  7113. return 0;
  7114. }
  7115. static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
  7116. {
  7117. struct rt_schedulable_data data = {
  7118. .tg = tg,
  7119. .rt_period = period,
  7120. .rt_runtime = runtime,
  7121. };
  7122. return walk_tg_tree(tg_schedulable, tg_nop, &data);
  7123. }
  7124. static int tg_set_bandwidth(struct task_group *tg,
  7125. u64 rt_period, u64 rt_runtime)
  7126. {
  7127. int i, err = 0;
  7128. mutex_lock(&rt_constraints_mutex);
  7129. read_lock(&tasklist_lock);
  7130. err = __rt_schedulable(tg, rt_period, rt_runtime);
  7131. if (err)
  7132. goto unlock;
  7133. raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock);
  7134. tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period);
  7135. tg->rt_bandwidth.rt_runtime = rt_runtime;
  7136. for_each_possible_cpu(i) {
  7137. struct rt_rq *rt_rq = tg->rt_rq[i];
  7138. raw_spin_lock(&rt_rq->rt_runtime_lock);
  7139. rt_rq->rt_runtime = rt_runtime;
  7140. raw_spin_unlock(&rt_rq->rt_runtime_lock);
  7141. }
  7142. raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock);
  7143. unlock:
  7144. read_unlock(&tasklist_lock);
  7145. mutex_unlock(&rt_constraints_mutex);
  7146. return err;
  7147. }
  7148. int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us)
  7149. {
  7150. u64 rt_runtime, rt_period;
  7151. rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period);
  7152. rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC;
  7153. if (rt_runtime_us < 0)
  7154. rt_runtime = RUNTIME_INF;
  7155. return tg_set_bandwidth(tg, rt_period, rt_runtime);
  7156. }
  7157. long sched_group_rt_runtime(struct task_group *tg)
  7158. {
  7159. u64 rt_runtime_us;
  7160. if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF)
  7161. return -1;
  7162. rt_runtime_us = tg->rt_bandwidth.rt_runtime;
  7163. do_div(rt_runtime_us, NSEC_PER_USEC);
  7164. return rt_runtime_us;
  7165. }
  7166. int sched_group_set_rt_period(struct task_group *tg, long rt_period_us)
  7167. {
  7168. u64 rt_runtime, rt_period;
  7169. rt_period = (u64)rt_period_us * NSEC_PER_USEC;
  7170. rt_runtime = tg->rt_bandwidth.rt_runtime;
  7171. if (rt_period == 0)
  7172. return -EINVAL;
  7173. return tg_set_bandwidth(tg, rt_period, rt_runtime);
  7174. }
  7175. long sched_group_rt_period(struct task_group *tg)
  7176. {
  7177. u64 rt_period_us;
  7178. rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period);
  7179. do_div(rt_period_us, NSEC_PER_USEC);
  7180. return rt_period_us;
  7181. }
  7182. static int sched_rt_global_constraints(void)
  7183. {
  7184. u64 runtime, period;
  7185. int ret = 0;
  7186. if (sysctl_sched_rt_period <= 0)
  7187. return -EINVAL;
  7188. runtime = global_rt_runtime();
  7189. period = global_rt_period();
  7190. /*
  7191. * Sanity check on the sysctl variables.
  7192. */
  7193. if (runtime > period && runtime != RUNTIME_INF)
  7194. return -EINVAL;
  7195. mutex_lock(&rt_constraints_mutex);
  7196. read_lock(&tasklist_lock);
  7197. ret = __rt_schedulable(NULL, 0, 0);
  7198. read_unlock(&tasklist_lock);
  7199. mutex_unlock(&rt_constraints_mutex);
  7200. return ret;
  7201. }
  7202. int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk)
  7203. {
  7204. /* Don't accept realtime tasks when there is no way for them to run */
  7205. if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0)
  7206. return 0;
  7207. return 1;
  7208. }
  7209. #else /* !CONFIG_RT_GROUP_SCHED */
  7210. static int sched_rt_global_constraints(void)
  7211. {
  7212. unsigned long flags;
  7213. int i;
  7214. if (sysctl_sched_rt_period <= 0)
  7215. return -EINVAL;
  7216. /*
  7217. * There's always some RT tasks in the root group
  7218. * -- migration, kstopmachine etc..
  7219. */
  7220. if (sysctl_sched_rt_runtime == 0)
  7221. return -EBUSY;
  7222. raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
  7223. for_each_possible_cpu(i) {
  7224. struct rt_rq *rt_rq = &cpu_rq(i)->rt;
  7225. raw_spin_lock(&rt_rq->rt_runtime_lock);
  7226. rt_rq->rt_runtime = global_rt_runtime();
  7227. raw_spin_unlock(&rt_rq->rt_runtime_lock);
  7228. }
  7229. raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags);
  7230. return 0;
  7231. }
  7232. #endif /* CONFIG_RT_GROUP_SCHED */
  7233. int sched_rt_handler(struct ctl_table *table, int write,
  7234. void __user *buffer, size_t *lenp,
  7235. loff_t *ppos)
  7236. {
  7237. int ret;
  7238. int old_period, old_runtime;
  7239. static DEFINE_MUTEX(mutex);
  7240. mutex_lock(&mutex);
  7241. old_period = sysctl_sched_rt_period;
  7242. old_runtime = sysctl_sched_rt_runtime;
  7243. ret = proc_dointvec(table, write, buffer, lenp, ppos);
  7244. if (!ret && write) {
  7245. ret = sched_rt_global_constraints();
  7246. if (ret) {
  7247. sysctl_sched_rt_period = old_period;
  7248. sysctl_sched_rt_runtime = old_runtime;
  7249. } else {
  7250. def_rt_bandwidth.rt_runtime = global_rt_runtime();
  7251. def_rt_bandwidth.rt_period =
  7252. ns_to_ktime(global_rt_period());
  7253. }
  7254. }
  7255. mutex_unlock(&mutex);
  7256. return ret;
  7257. }
  7258. #ifdef CONFIG_CGROUP_SCHED
  7259. /* return corresponding task_group object of a cgroup */
  7260. static inline struct task_group *cgroup_tg(struct cgroup *cgrp)
  7261. {
  7262. return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id),
  7263. struct task_group, css);
  7264. }
  7265. static struct cgroup_subsys_state *
  7266. cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp)
  7267. {
  7268. struct task_group *tg, *parent;
  7269. if (!cgrp->parent) {
  7270. /* This is early initialization for the top cgroup */
  7271. return &init_task_group.css;
  7272. }
  7273. parent = cgroup_tg(cgrp->parent);
  7274. tg = sched_create_group(parent);
  7275. if (IS_ERR(tg))
  7276. return ERR_PTR(-ENOMEM);
  7277. return &tg->css;
  7278. }
  7279. static void
  7280. cpu_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
  7281. {
  7282. struct task_group *tg = cgroup_tg(cgrp);
  7283. sched_destroy_group(tg);
  7284. }
  7285. static int
  7286. cpu_cgroup_can_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
  7287. {
  7288. #ifdef CONFIG_RT_GROUP_SCHED
  7289. if (!sched_rt_can_attach(cgroup_tg(cgrp), tsk))
  7290. return -EINVAL;
  7291. #else
  7292. /* We don't support RT-tasks being in separate groups */
  7293. if (tsk->sched_class != &fair_sched_class)
  7294. return -EINVAL;
  7295. #endif
  7296. return 0;
  7297. }
  7298. static int
  7299. cpu_cgroup_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
  7300. struct task_struct *tsk, bool threadgroup)
  7301. {
  7302. int retval = cpu_cgroup_can_attach_task(cgrp, tsk);
  7303. if (retval)
  7304. return retval;
  7305. if (threadgroup) {
  7306. struct task_struct *c;
  7307. rcu_read_lock();
  7308. list_for_each_entry_rcu(c, &tsk->thread_group, thread_group) {
  7309. retval = cpu_cgroup_can_attach_task(cgrp, c);
  7310. if (retval) {
  7311. rcu_read_unlock();
  7312. return retval;
  7313. }
  7314. }
  7315. rcu_read_unlock();
  7316. }
  7317. return 0;
  7318. }
  7319. static void
  7320. cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
  7321. struct cgroup *old_cont, struct task_struct *tsk,
  7322. bool threadgroup)
  7323. {
  7324. sched_move_task(tsk);
  7325. if (threadgroup) {
  7326. struct task_struct *c;
  7327. rcu_read_lock();
  7328. list_for_each_entry_rcu(c, &tsk->thread_group, thread_group) {
  7329. sched_move_task(c);
  7330. }
  7331. rcu_read_unlock();
  7332. }
  7333. }
  7334. #ifdef CONFIG_FAIR_GROUP_SCHED
  7335. static int cpu_shares_write_u64(struct cgroup *cgrp, struct cftype *cftype,
  7336. u64 shareval)
  7337. {
  7338. return sched_group_set_shares(cgroup_tg(cgrp), shareval);
  7339. }
  7340. static u64 cpu_shares_read_u64(struct cgroup *cgrp, struct cftype *cft)
  7341. {
  7342. struct task_group *tg = cgroup_tg(cgrp);
  7343. return (u64) tg->shares;
  7344. }
  7345. #endif /* CONFIG_FAIR_GROUP_SCHED */
  7346. #ifdef CONFIG_RT_GROUP_SCHED
  7347. static int cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft,
  7348. s64 val)
  7349. {
  7350. return sched_group_set_rt_runtime(cgroup_tg(cgrp), val);
  7351. }
  7352. static s64 cpu_rt_runtime_read(struct cgroup *cgrp, struct cftype *cft)
  7353. {
  7354. return sched_group_rt_runtime(cgroup_tg(cgrp));
  7355. }
  7356. static int cpu_rt_period_write_uint(struct cgroup *cgrp, struct cftype *cftype,
  7357. u64 rt_period_us)
  7358. {
  7359. return sched_group_set_rt_period(cgroup_tg(cgrp), rt_period_us);
  7360. }
  7361. static u64 cpu_rt_period_read_uint(struct cgroup *cgrp, struct cftype *cft)
  7362. {
  7363. return sched_group_rt_period(cgroup_tg(cgrp));
  7364. }
  7365. #endif /* CONFIG_RT_GROUP_SCHED */
  7366. static struct cftype cpu_files[] = {
  7367. #ifdef CONFIG_FAIR_GROUP_SCHED
  7368. {
  7369. .name = "shares",
  7370. .read_u64 = cpu_shares_read_u64,
  7371. .write_u64 = cpu_shares_write_u64,
  7372. },
  7373. #endif
  7374. #ifdef CONFIG_RT_GROUP_SCHED
  7375. {
  7376. .name = "rt_runtime_us",
  7377. .read_s64 = cpu_rt_runtime_read,
  7378. .write_s64 = cpu_rt_runtime_write,
  7379. },
  7380. {
  7381. .name = "rt_period_us",
  7382. .read_u64 = cpu_rt_period_read_uint,
  7383. .write_u64 = cpu_rt_period_write_uint,
  7384. },
  7385. #endif
  7386. };
  7387. static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont)
  7388. {
  7389. return cgroup_add_files(cont, ss, cpu_files, ARRAY_SIZE(cpu_files));
  7390. }
  7391. struct cgroup_subsys cpu_cgroup_subsys = {
  7392. .name = "cpu",
  7393. .create = cpu_cgroup_create,
  7394. .destroy = cpu_cgroup_destroy,
  7395. .can_attach = cpu_cgroup_can_attach,
  7396. .attach = cpu_cgroup_attach,
  7397. .populate = cpu_cgroup_populate,
  7398. .subsys_id = cpu_cgroup_subsys_id,
  7399. .early_init = 1,
  7400. };
  7401. #endif /* CONFIG_CGROUP_SCHED */
  7402. #ifdef CONFIG_CGROUP_CPUACCT
  7403. /*
  7404. * CPU accounting code for task groups.
  7405. *
  7406. * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
  7407. * (balbir@in.ibm.com).
  7408. */
  7409. /* track cpu usage of a group of tasks and its child groups */
  7410. struct cpuacct {
  7411. struct cgroup_subsys_state css;
  7412. /* cpuusage holds pointer to a u64-type object on every cpu */
  7413. u64 *cpuusage;
  7414. struct percpu_counter cpustat[CPUACCT_STAT_NSTATS];
  7415. struct cpuacct *parent;
  7416. };
  7417. struct cgroup_subsys cpuacct_subsys;
  7418. /* return cpu accounting group corresponding to this container */
  7419. static inline struct cpuacct *cgroup_ca(struct cgroup *cgrp)
  7420. {
  7421. return container_of(cgroup_subsys_state(cgrp, cpuacct_subsys_id),
  7422. struct cpuacct, css);
  7423. }
  7424. /* return cpu accounting group to which this task belongs */
  7425. static inline struct cpuacct *task_ca(struct task_struct *tsk)
  7426. {
  7427. return container_of(task_subsys_state(tsk, cpuacct_subsys_id),
  7428. struct cpuacct, css);
  7429. }
  7430. /* create a new cpu accounting group */
  7431. static struct cgroup_subsys_state *cpuacct_create(
  7432. struct cgroup_subsys *ss, struct cgroup *cgrp)
  7433. {
  7434. struct cpuacct *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
  7435. int i;
  7436. if (!ca)
  7437. goto out;
  7438. ca->cpuusage = alloc_percpu(u64);
  7439. if (!ca->cpuusage)
  7440. goto out_free_ca;
  7441. for (i = 0; i < CPUACCT_STAT_NSTATS; i++)
  7442. if (percpu_counter_init(&ca->cpustat[i], 0))
  7443. goto out_free_counters;
  7444. if (cgrp->parent)
  7445. ca->parent = cgroup_ca(cgrp->parent);
  7446. return &ca->css;
  7447. out_free_counters:
  7448. while (--i >= 0)
  7449. percpu_counter_destroy(&ca->cpustat[i]);
  7450. free_percpu(ca->cpuusage);
  7451. out_free_ca:
  7452. kfree(ca);
  7453. out:
  7454. return ERR_PTR(-ENOMEM);
  7455. }
  7456. /* destroy an existing cpu accounting group */
  7457. static void
  7458. cpuacct_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
  7459. {
  7460. struct cpuacct *ca = cgroup_ca(cgrp);
  7461. int i;
  7462. for (i = 0; i < CPUACCT_STAT_NSTATS; i++)
  7463. percpu_counter_destroy(&ca->cpustat[i]);
  7464. free_percpu(ca->cpuusage);
  7465. kfree(ca);
  7466. }
  7467. static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu)
  7468. {
  7469. u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
  7470. u64 data;
  7471. #ifndef CONFIG_64BIT
  7472. /*
  7473. * Take rq->lock to make 64-bit read safe on 32-bit platforms.
  7474. */
  7475. raw_spin_lock_irq(&cpu_rq(cpu)->lock);
  7476. data = *cpuusage;
  7477. raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
  7478. #else
  7479. data = *cpuusage;
  7480. #endif
  7481. return data;
  7482. }
  7483. static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val)
  7484. {
  7485. u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
  7486. #ifndef CONFIG_64BIT
  7487. /*
  7488. * Take rq->lock to make 64-bit write safe on 32-bit platforms.
  7489. */
  7490. raw_spin_lock_irq(&cpu_rq(cpu)->lock);
  7491. *cpuusage = val;
  7492. raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
  7493. #else
  7494. *cpuusage = val;
  7495. #endif
  7496. }
  7497. /* return total cpu usage (in nanoseconds) of a group */
  7498. static u64 cpuusage_read(struct cgroup *cgrp, struct cftype *cft)
  7499. {
  7500. struct cpuacct *ca = cgroup_ca(cgrp);
  7501. u64 totalcpuusage = 0;
  7502. int i;
  7503. for_each_present_cpu(i)
  7504. totalcpuusage += cpuacct_cpuusage_read(ca, i);
  7505. return totalcpuusage;
  7506. }
  7507. static int cpuusage_write(struct cgroup *cgrp, struct cftype *cftype,
  7508. u64 reset)
  7509. {
  7510. struct cpuacct *ca = cgroup_ca(cgrp);
  7511. int err = 0;
  7512. int i;
  7513. if (reset) {
  7514. err = -EINVAL;
  7515. goto out;
  7516. }
  7517. for_each_present_cpu(i)
  7518. cpuacct_cpuusage_write(ca, i, 0);
  7519. out:
  7520. return err;
  7521. }
  7522. static int cpuacct_percpu_seq_read(struct cgroup *cgroup, struct cftype *cft,
  7523. struct seq_file *m)
  7524. {
  7525. struct cpuacct *ca = cgroup_ca(cgroup);
  7526. u64 percpu;
  7527. int i;
  7528. for_each_present_cpu(i) {
  7529. percpu = cpuacct_cpuusage_read(ca, i);
  7530. seq_printf(m, "%llu ", (unsigned long long) percpu);
  7531. }
  7532. seq_printf(m, "\n");
  7533. return 0;
  7534. }
  7535. static const char *cpuacct_stat_desc[] = {
  7536. [CPUACCT_STAT_USER] = "user",
  7537. [CPUACCT_STAT_SYSTEM] = "system",
  7538. };
  7539. static int cpuacct_stats_show(struct cgroup *cgrp, struct cftype *cft,
  7540. struct cgroup_map_cb *cb)
  7541. {
  7542. struct cpuacct *ca = cgroup_ca(cgrp);
  7543. int i;
  7544. for (i = 0; i < CPUACCT_STAT_NSTATS; i++) {
  7545. s64 val = percpu_counter_read(&ca->cpustat[i]);
  7546. val = cputime64_to_clock_t(val);
  7547. cb->fill(cb, cpuacct_stat_desc[i], val);
  7548. }
  7549. return 0;
  7550. }
  7551. static struct cftype files[] = {
  7552. {
  7553. .name = "usage",
  7554. .read_u64 = cpuusage_read,
  7555. .write_u64 = cpuusage_write,
  7556. },
  7557. {
  7558. .name = "usage_percpu",
  7559. .read_seq_string = cpuacct_percpu_seq_read,
  7560. },
  7561. {
  7562. .name = "stat",
  7563. .read_map = cpuacct_stats_show,
  7564. },
  7565. };
  7566. static int cpuacct_populate(struct cgroup_subsys *ss, struct cgroup *cgrp)
  7567. {
  7568. return cgroup_add_files(cgrp, ss, files, ARRAY_SIZE(files));
  7569. }
  7570. /*
  7571. * charge this task's execution time to its accounting group.
  7572. *
  7573. * called with rq->lock held.
  7574. */
  7575. static void cpuacct_charge(struct task_struct *tsk, u64 cputime)
  7576. {
  7577. struct cpuacct *ca;
  7578. int cpu;
  7579. if (unlikely(!cpuacct_subsys.active))
  7580. return;
  7581. cpu = task_cpu(tsk);
  7582. rcu_read_lock();
  7583. ca = task_ca(tsk);
  7584. for (; ca; ca = ca->parent) {
  7585. u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
  7586. *cpuusage += cputime;
  7587. }
  7588. rcu_read_unlock();
  7589. }
  7590. /*
  7591. * When CONFIG_VIRT_CPU_ACCOUNTING is enabled one jiffy can be very large
  7592. * in cputime_t units. As a result, cpuacct_update_stats calls
  7593. * percpu_counter_add with values large enough to always overflow the
  7594. * per cpu batch limit causing bad SMP scalability.
  7595. *
  7596. * To fix this we scale percpu_counter_batch by cputime_one_jiffy so we
  7597. * batch the same amount of time with CONFIG_VIRT_CPU_ACCOUNTING disabled
  7598. * and enabled. We cap it at INT_MAX which is the largest allowed batch value.
  7599. */
  7600. #ifdef CONFIG_SMP
  7601. #define CPUACCT_BATCH \
  7602. min_t(long, percpu_counter_batch * cputime_one_jiffy, INT_MAX)
  7603. #else
  7604. #define CPUACCT_BATCH 0
  7605. #endif
  7606. /*
  7607. * Charge the system/user time to the task's accounting group.
  7608. */
  7609. static void cpuacct_update_stats(struct task_struct *tsk,
  7610. enum cpuacct_stat_index idx, cputime_t val)
  7611. {
  7612. struct cpuacct *ca;
  7613. int batch = CPUACCT_BATCH;
  7614. if (unlikely(!cpuacct_subsys.active))
  7615. return;
  7616. rcu_read_lock();
  7617. ca = task_ca(tsk);
  7618. do {
  7619. __percpu_counter_add(&ca->cpustat[idx], val, batch);
  7620. ca = ca->parent;
  7621. } while (ca);
  7622. rcu_read_unlock();
  7623. }
  7624. struct cgroup_subsys cpuacct_subsys = {
  7625. .name = "cpuacct",
  7626. .create = cpuacct_create,
  7627. .destroy = cpuacct_destroy,
  7628. .populate = cpuacct_populate,
  7629. .subsys_id = cpuacct_subsys_id,
  7630. };
  7631. #endif /* CONFIG_CGROUP_CPUACCT */
  7632. #ifndef CONFIG_SMP
  7633. int rcu_expedited_torture_stats(char *page)
  7634. {
  7635. return 0;
  7636. }
  7637. EXPORT_SYMBOL_GPL(rcu_expedited_torture_stats);
  7638. void synchronize_sched_expedited(void)
  7639. {
  7640. }
  7641. EXPORT_SYMBOL_GPL(synchronize_sched_expedited);
  7642. #else /* #ifndef CONFIG_SMP */
  7643. static DEFINE_PER_CPU(struct migration_req, rcu_migration_req);
  7644. static DEFINE_MUTEX(rcu_sched_expedited_mutex);
  7645. #define RCU_EXPEDITED_STATE_POST -2
  7646. #define RCU_EXPEDITED_STATE_IDLE -1
  7647. static int rcu_expedited_state = RCU_EXPEDITED_STATE_IDLE;
  7648. int rcu_expedited_torture_stats(char *page)
  7649. {
  7650. int cnt = 0;
  7651. int cpu;
  7652. cnt += sprintf(&page[cnt], "state: %d /", rcu_expedited_state);
  7653. for_each_online_cpu(cpu) {
  7654. cnt += sprintf(&page[cnt], " %d:%d",
  7655. cpu, per_cpu(rcu_migration_req, cpu).dest_cpu);
  7656. }
  7657. cnt += sprintf(&page[cnt], "\n");
  7658. return cnt;
  7659. }
  7660. EXPORT_SYMBOL_GPL(rcu_expedited_torture_stats);
  7661. static long synchronize_sched_expedited_count;
  7662. /*
  7663. * Wait for an rcu-sched grace period to elapse, but use "big hammer"
  7664. * approach to force grace period to end quickly. This consumes
  7665. * significant time on all CPUs, and is thus not recommended for
  7666. * any sort of common-case code.
  7667. *
  7668. * Note that it is illegal to call this function while holding any
  7669. * lock that is acquired by a CPU-hotplug notifier. Failing to
  7670. * observe this restriction will result in deadlock.
  7671. */
  7672. void synchronize_sched_expedited(void)
  7673. {
  7674. int cpu;
  7675. unsigned long flags;
  7676. bool need_full_sync = 0;
  7677. struct rq *rq;
  7678. struct migration_req *req;
  7679. long snap;
  7680. int trycount = 0;
  7681. smp_mb(); /* ensure prior mod happens before capturing snap. */
  7682. snap = ACCESS_ONCE(synchronize_sched_expedited_count) + 1;
  7683. get_online_cpus();
  7684. while (!mutex_trylock(&rcu_sched_expedited_mutex)) {
  7685. put_online_cpus();
  7686. if (trycount++ < 10)
  7687. udelay(trycount * num_online_cpus());
  7688. else {
  7689. synchronize_sched();
  7690. return;
  7691. }
  7692. if (ACCESS_ONCE(synchronize_sched_expedited_count) - snap > 0) {
  7693. smp_mb(); /* ensure test happens before caller kfree */
  7694. return;
  7695. }
  7696. get_online_cpus();
  7697. }
  7698. rcu_expedited_state = RCU_EXPEDITED_STATE_POST;
  7699. for_each_online_cpu(cpu) {
  7700. rq = cpu_rq(cpu);
  7701. req = &per_cpu(rcu_migration_req, cpu);
  7702. init_completion(&req->done);
  7703. req->task = NULL;
  7704. req->dest_cpu = RCU_MIGRATION_NEED_QS;
  7705. raw_spin_lock_irqsave(&rq->lock, flags);
  7706. list_add(&req->list, &rq->migration_queue);
  7707. raw_spin_unlock_irqrestore(&rq->lock, flags);
  7708. wake_up_process(rq->migration_thread);
  7709. }
  7710. for_each_online_cpu(cpu) {
  7711. rcu_expedited_state = cpu;
  7712. req = &per_cpu(rcu_migration_req, cpu);
  7713. rq = cpu_rq(cpu);
  7714. wait_for_completion(&req->done);
  7715. raw_spin_lock_irqsave(&rq->lock, flags);
  7716. if (unlikely(req->dest_cpu == RCU_MIGRATION_MUST_SYNC))
  7717. need_full_sync = 1;
  7718. req->dest_cpu = RCU_MIGRATION_IDLE;
  7719. raw_spin_unlock_irqrestore(&rq->lock, flags);
  7720. }
  7721. rcu_expedited_state = RCU_EXPEDITED_STATE_IDLE;
  7722. synchronize_sched_expedited_count++;
  7723. mutex_unlock(&rcu_sched_expedited_mutex);
  7724. put_online_cpus();
  7725. if (need_full_sync)
  7726. synchronize_sched();
  7727. }
  7728. EXPORT_SYMBOL_GPL(synchronize_sched_expedited);
  7729. #endif /* #else #ifndef CONFIG_SMP */