11da177e4SLinus Torvalds /* 2c54fce6eSTejun Heo * kernel/workqueue.c - generic async execution with shared worker pool 31da177e4SLinus Torvalds * 4c54fce6eSTejun Heo * Copyright (C) 2002 Ingo Molnar 51da177e4SLinus Torvalds * 61da177e4SLinus Torvalds * Derived from the taskqueue/keventd code by: 71da177e4SLinus Torvalds * David Woodhouse <dwmw2@infradead.org> 8e1f8e874SFrancois Cami * Andrew Morton 91da177e4SLinus Torvalds * Kai Petzke <wpp@marie.physik.tu-berlin.de> 101da177e4SLinus Torvalds * Theodore Ts'o <tytso@mit.edu> 1189ada679SChristoph Lameter * 12cde53535SChristoph Lameter * Made to use alloc_percpu by Christoph Lameter. 13c54fce6eSTejun Heo * 14c54fce6eSTejun Heo * Copyright (C) 2010 SUSE Linux Products GmbH 15c54fce6eSTejun Heo * Copyright (C) 2010 Tejun Heo <tj@kernel.org> 16c54fce6eSTejun Heo * 17c54fce6eSTejun Heo * This is the generic async execution mechanism. Work items as are 18c54fce6eSTejun Heo * executed in process context. The worker pool is shared and 19c54fce6eSTejun Heo * automatically managed. There is one worker pool for each CPU and 20c54fce6eSTejun Heo * one extra for works which are better served by workers which are 21c54fce6eSTejun Heo * not bound to any specific CPU. 22c54fce6eSTejun Heo * 23c54fce6eSTejun Heo * Please read Documentation/workqueue.txt for details. 241da177e4SLinus Torvalds */ 251da177e4SLinus Torvalds 269984de1aSPaul Gortmaker #include <linux/export.h> 271da177e4SLinus Torvalds #include <linux/kernel.h> 281da177e4SLinus Torvalds #include <linux/sched.h> 291da177e4SLinus Torvalds #include <linux/init.h> 301da177e4SLinus Torvalds #include <linux/signal.h> 311da177e4SLinus Torvalds #include <linux/completion.h> 321da177e4SLinus Torvalds #include <linux/workqueue.h> 331da177e4SLinus Torvalds #include <linux/slab.h> 341da177e4SLinus Torvalds #include <linux/cpu.h> 351da177e4SLinus Torvalds #include <linux/notifier.h> 361da177e4SLinus Torvalds #include <linux/kthread.h> 371fa44ecaSJames Bottomley #include <linux/hardirq.h> 3846934023SChristoph Lameter #include <linux/mempolicy.h> 39341a5958SRafael J. Wysocki #include <linux/freezer.h> 40d5abe669SPeter Zijlstra #include <linux/kallsyms.h> 41d5abe669SPeter Zijlstra #include <linux/debug_locks.h> 424e6045f1SJohannes Berg #include <linux/lockdep.h> 43c34056a3STejun Heo #include <linux/idr.h> 44e22bee78STejun Heo 45e22bee78STejun Heo #include "workqueue_sched.h" 461da177e4SLinus Torvalds 47c8e55f36STejun Heo enum { 48db7bccf4STejun Heo /* global_cwq flags */ 49e22bee78STejun Heo GCWQ_MANAGE_WORKERS = 1 << 0, /* need to manage workers */ 50e22bee78STejun Heo GCWQ_MANAGING_WORKERS = 1 << 1, /* managing workers */ 51e22bee78STejun Heo GCWQ_DISASSOCIATED = 1 << 2, /* cpu can't serve workers */ 52db7bccf4STejun Heo GCWQ_FREEZING = 1 << 3, /* freeze in progress */ 53649027d7STejun Heo GCWQ_HIGHPRI_PENDING = 1 << 4, /* highpri works on queue */ 54db7bccf4STejun Heo 55c8e55f36STejun Heo /* worker flags */ 56c8e55f36STejun Heo WORKER_STARTED = 1 << 0, /* started */ 57c8e55f36STejun Heo WORKER_DIE = 1 << 1, /* die die die */ 58c8e55f36STejun Heo WORKER_IDLE = 1 << 2, /* is idle */ 59e22bee78STejun Heo WORKER_PREP = 1 << 3, /* preparing to run works */ 60db7bccf4STejun Heo WORKER_ROGUE = 1 << 4, /* not bound to any cpu */ 61e22bee78STejun Heo WORKER_REBIND = 1 << 5, /* mom is home, come back */ 62fb0e7bebSTejun Heo WORKER_CPU_INTENSIVE = 1 << 6, /* cpu intensive */ 63f3421797STejun Heo WORKER_UNBOUND = 1 << 7, /* worker is unbound */ 64e22bee78STejun Heo 65fb0e7bebSTejun Heo WORKER_NOT_RUNNING = WORKER_PREP | WORKER_ROGUE | WORKER_REBIND | 66f3421797STejun Heo WORKER_CPU_INTENSIVE | WORKER_UNBOUND, 67db7bccf4STejun Heo 68db7bccf4STejun Heo /* gcwq->trustee_state */ 69db7bccf4STejun Heo TRUSTEE_START = 0, /* start */ 70db7bccf4STejun Heo TRUSTEE_IN_CHARGE = 1, /* trustee in charge of gcwq */ 71db7bccf4STejun Heo TRUSTEE_BUTCHER = 2, /* butcher workers */ 72db7bccf4STejun Heo TRUSTEE_RELEASE = 3, /* release workers */ 73db7bccf4STejun Heo TRUSTEE_DONE = 4, /* trustee is done */ 74c8e55f36STejun Heo 75c8e55f36STejun Heo BUSY_WORKER_HASH_ORDER = 6, /* 64 pointers */ 76c8e55f36STejun Heo BUSY_WORKER_HASH_SIZE = 1 << BUSY_WORKER_HASH_ORDER, 77c8e55f36STejun Heo BUSY_WORKER_HASH_MASK = BUSY_WORKER_HASH_SIZE - 1, 78db7bccf4STejun Heo 79e22bee78STejun Heo MAX_IDLE_WORKERS_RATIO = 4, /* 1/4 of busy can be idle */ 80e22bee78STejun Heo IDLE_WORKER_TIMEOUT = 300 * HZ, /* keep idle ones for 5 mins */ 81e22bee78STejun Heo 823233cdbdSTejun Heo MAYDAY_INITIAL_TIMEOUT = HZ / 100 >= 2 ? HZ / 100 : 2, 833233cdbdSTejun Heo /* call for help after 10ms 843233cdbdSTejun Heo (min two ticks) */ 85e22bee78STejun Heo MAYDAY_INTERVAL = HZ / 10, /* and then every 100ms */ 86e22bee78STejun Heo CREATE_COOLDOWN = HZ, /* time to breath after fail */ 87db7bccf4STejun Heo TRUSTEE_COOLDOWN = HZ / 10, /* for trustee draining */ 881da177e4SLinus Torvalds 891da177e4SLinus Torvalds /* 90e22bee78STejun Heo * Rescue workers are used only on emergencies and shared by 91e22bee78STejun Heo * all cpus. Give -20. 92e22bee78STejun Heo */ 93e22bee78STejun Heo RESCUER_NICE_LEVEL = -20, 94c8e55f36STejun Heo }; 95c8e55f36STejun Heo 961da177e4SLinus Torvalds /* 974690c4abSTejun Heo * Structure fields follow one of the following exclusion rules. 984690c4abSTejun Heo * 99e41e704bSTejun Heo * I: Modifiable by initialization/destruction paths and read-only for 100e41e704bSTejun Heo * everyone else. 1014690c4abSTejun Heo * 102e22bee78STejun Heo * P: Preemption protected. Disabling preemption is enough and should 103e22bee78STejun Heo * only be modified and accessed from the local cpu. 104e22bee78STejun Heo * 1058b03ae3cSTejun Heo * L: gcwq->lock protected. Access with gcwq->lock held. 1064690c4abSTejun Heo * 107e22bee78STejun Heo * X: During normal operation, modification requires gcwq->lock and 108e22bee78STejun Heo * should be done only from local cpu. Either disabling preemption 109e22bee78STejun Heo * on local cpu or grabbing gcwq->lock is enough for read access. 110f3421797STejun Heo * If GCWQ_DISASSOCIATED is set, it's identical to L. 111e22bee78STejun Heo * 11273f53c4aSTejun Heo * F: wq->flush_mutex protected. 11373f53c4aSTejun Heo * 1144690c4abSTejun Heo * W: workqueue_lock protected. 1154690c4abSTejun Heo */ 1164690c4abSTejun Heo 1178b03ae3cSTejun Heo struct global_cwq; 118bd7bdd43STejun Heo struct worker_pool; 119c34056a3STejun Heo 120e22bee78STejun Heo /* 121e22bee78STejun Heo * The poor guys doing the actual heavy lifting. All on-duty workers 122e22bee78STejun Heo * are either serving the manager role, on idle list or on busy hash. 123e22bee78STejun Heo */ 124c34056a3STejun Heo struct worker { 125c8e55f36STejun Heo /* on idle list while idle, on busy hash table while busy */ 126c8e55f36STejun Heo union { 127c8e55f36STejun Heo struct list_head entry; /* L: while idle */ 128c8e55f36STejun Heo struct hlist_node hentry; /* L: while busy */ 129c8e55f36STejun Heo }; 130c8e55f36STejun Heo 131c34056a3STejun Heo struct work_struct *current_work; /* L: work being processed */ 1328cca0eeaSTejun Heo struct cpu_workqueue_struct *current_cwq; /* L: current_work's cwq */ 133affee4b2STejun Heo struct list_head scheduled; /* L: scheduled works */ 134c34056a3STejun Heo struct task_struct *task; /* I: worker task */ 135bd7bdd43STejun Heo struct worker_pool *pool; /* I: the associated pool */ 136e22bee78STejun Heo /* 64 bytes boundary on 64bit, 32 on 32bit */ 137e22bee78STejun Heo unsigned long last_active; /* L: last active timestamp */ 138e22bee78STejun Heo unsigned int flags; /* X: flags */ 139c34056a3STejun Heo int id; /* I: worker id */ 140e22bee78STejun Heo struct work_struct rebind_work; /* L: rebind worker to cpu */ 141c34056a3STejun Heo }; 142c34056a3STejun Heo 143bd7bdd43STejun Heo struct worker_pool { 144bd7bdd43STejun Heo struct global_cwq *gcwq; /* I: the owning gcwq */ 145bd7bdd43STejun Heo 146bd7bdd43STejun Heo struct list_head worklist; /* L: list of pending works */ 147bd7bdd43STejun Heo int nr_workers; /* L: total number of workers */ 148bd7bdd43STejun Heo int nr_idle; /* L: currently idle ones */ 149bd7bdd43STejun Heo 150bd7bdd43STejun Heo struct list_head idle_list; /* X: list of idle workers */ 151bd7bdd43STejun Heo struct timer_list idle_timer; /* L: worker idle timeout */ 152bd7bdd43STejun Heo struct timer_list mayday_timer; /* L: SOS timer for workers */ 153bd7bdd43STejun Heo 154bd7bdd43STejun Heo struct ida worker_ida; /* L: for worker IDs */ 155bd7bdd43STejun Heo struct worker *first_idle; /* L: first idle worker */ 156bd7bdd43STejun Heo }; 157bd7bdd43STejun Heo 1584690c4abSTejun Heo /* 159e22bee78STejun Heo * Global per-cpu workqueue. There's one and only one for each cpu 160e22bee78STejun Heo * and all works are queued and processed here regardless of their 161e22bee78STejun Heo * target workqueues. 1628b03ae3cSTejun Heo */ 1638b03ae3cSTejun Heo struct global_cwq { 1648b03ae3cSTejun Heo spinlock_t lock; /* the gcwq lock */ 1658b03ae3cSTejun Heo unsigned int cpu; /* I: the associated cpu */ 166db7bccf4STejun Heo unsigned int flags; /* L: GCWQ_* flags */ 167c8e55f36STejun Heo 168bd7bdd43STejun Heo /* workers are chained either in busy_hash or pool idle_list */ 169c8e55f36STejun Heo struct hlist_head busy_hash[BUSY_WORKER_HASH_SIZE]; 170c8e55f36STejun Heo /* L: hash of busy workers */ 171c8e55f36STejun Heo 172bd7bdd43STejun Heo struct worker_pool pool; /* the worker pools */ 173db7bccf4STejun Heo 174db7bccf4STejun Heo struct task_struct *trustee; /* L: for gcwq shutdown */ 175db7bccf4STejun Heo unsigned int trustee_state; /* L: trustee state */ 176db7bccf4STejun Heo wait_queue_head_t trustee_wait; /* trustee wait */ 1778b03ae3cSTejun Heo } ____cacheline_aligned_in_smp; 1788b03ae3cSTejun Heo 1798b03ae3cSTejun Heo /* 180502ca9d8STejun Heo * The per-CPU workqueue. The lower WORK_STRUCT_FLAG_BITS of 1810f900049STejun Heo * work_struct->data are used for flags and thus cwqs need to be 1820f900049STejun Heo * aligned at two's power of the number of flag bits. 1831da177e4SLinus Torvalds */ 1841da177e4SLinus Torvalds struct cpu_workqueue_struct { 185bd7bdd43STejun Heo struct worker_pool *pool; /* I: the associated pool */ 1864690c4abSTejun Heo struct workqueue_struct *wq; /* I: the owning workqueue */ 18773f53c4aSTejun Heo int work_color; /* L: current color */ 18873f53c4aSTejun Heo int flush_color; /* L: flushing color */ 18973f53c4aSTejun Heo int nr_in_flight[WORK_NR_COLORS]; 19073f53c4aSTejun Heo /* L: nr of in_flight works */ 1911e19ffc6STejun Heo int nr_active; /* L: nr of active works */ 192a0a1a5fdSTejun Heo int max_active; /* L: max active works */ 1931e19ffc6STejun Heo struct list_head delayed_works; /* L: delayed works */ 1940f900049STejun Heo }; 1951da177e4SLinus Torvalds 1961da177e4SLinus Torvalds /* 19773f53c4aSTejun Heo * Structure used to wait for workqueue flush. 19873f53c4aSTejun Heo */ 19973f53c4aSTejun Heo struct wq_flusher { 20073f53c4aSTejun Heo struct list_head list; /* F: list of flushers */ 20173f53c4aSTejun Heo int flush_color; /* F: flush color waiting for */ 20273f53c4aSTejun Heo struct completion done; /* flush completion */ 20373f53c4aSTejun Heo }; 2041da177e4SLinus Torvalds 20573f53c4aSTejun Heo /* 206f2e005aaSTejun Heo * All cpumasks are assumed to be always set on UP and thus can't be 207f2e005aaSTejun Heo * used to determine whether there's something to be done. 208f2e005aaSTejun Heo */ 209f2e005aaSTejun Heo #ifdef CONFIG_SMP 210f2e005aaSTejun Heo typedef cpumask_var_t mayday_mask_t; 211f2e005aaSTejun Heo #define mayday_test_and_set_cpu(cpu, mask) \ 212f2e005aaSTejun Heo cpumask_test_and_set_cpu((cpu), (mask)) 213f2e005aaSTejun Heo #define mayday_clear_cpu(cpu, mask) cpumask_clear_cpu((cpu), (mask)) 214f2e005aaSTejun Heo #define for_each_mayday_cpu(cpu, mask) for_each_cpu((cpu), (mask)) 2159c37547aSTejun Heo #define alloc_mayday_mask(maskp, gfp) zalloc_cpumask_var((maskp), (gfp)) 216f2e005aaSTejun Heo #define free_mayday_mask(mask) free_cpumask_var((mask)) 217f2e005aaSTejun Heo #else 218f2e005aaSTejun Heo typedef unsigned long mayday_mask_t; 219f2e005aaSTejun Heo #define mayday_test_and_set_cpu(cpu, mask) test_and_set_bit(0, &(mask)) 220f2e005aaSTejun Heo #define mayday_clear_cpu(cpu, mask) clear_bit(0, &(mask)) 221f2e005aaSTejun Heo #define for_each_mayday_cpu(cpu, mask) if ((cpu) = 0, (mask)) 222f2e005aaSTejun Heo #define alloc_mayday_mask(maskp, gfp) true 223f2e005aaSTejun Heo #define free_mayday_mask(mask) do { } while (0) 224f2e005aaSTejun Heo #endif 2251da177e4SLinus Torvalds 2261da177e4SLinus Torvalds /* 2271da177e4SLinus Torvalds * The externally visible workqueue abstraction is an array of 2281da177e4SLinus Torvalds * per-CPU workqueues: 2291da177e4SLinus Torvalds */ 2301da177e4SLinus Torvalds struct workqueue_struct { 2319c5a2ba7STejun Heo unsigned int flags; /* W: WQ_* flags */ 232bdbc5dd7STejun Heo union { 233bdbc5dd7STejun Heo struct cpu_workqueue_struct __percpu *pcpu; 234bdbc5dd7STejun Heo struct cpu_workqueue_struct *single; 235bdbc5dd7STejun Heo unsigned long v; 236bdbc5dd7STejun Heo } cpu_wq; /* I: cwq's */ 2374690c4abSTejun Heo struct list_head list; /* W: list of all workqueues */ 23873f53c4aSTejun Heo 23973f53c4aSTejun Heo struct mutex flush_mutex; /* protects wq flushing */ 24073f53c4aSTejun Heo int work_color; /* F: current work color */ 24173f53c4aSTejun Heo int flush_color; /* F: current flush color */ 24273f53c4aSTejun Heo atomic_t nr_cwqs_to_flush; /* flush in progress */ 24373f53c4aSTejun Heo struct wq_flusher *first_flusher; /* F: first flusher */ 24473f53c4aSTejun Heo struct list_head flusher_queue; /* F: flush waiters */ 24573f53c4aSTejun Heo struct list_head flusher_overflow; /* F: flush overflow list */ 24673f53c4aSTejun Heo 247f2e005aaSTejun Heo mayday_mask_t mayday_mask; /* cpus requesting rescue */ 248e22bee78STejun Heo struct worker *rescuer; /* I: rescue worker */ 249e22bee78STejun Heo 2509c5a2ba7STejun Heo int nr_drainers; /* W: drain in progress */ 251dcd989cbSTejun Heo int saved_max_active; /* W: saved cwq max_active */ 2524e6045f1SJohannes Berg #ifdef CONFIG_LOCKDEP 2534e6045f1SJohannes Berg struct lockdep_map lockdep_map; 2544e6045f1SJohannes Berg #endif 255b196be89STejun Heo char name[]; /* I: workqueue name */ 2561da177e4SLinus Torvalds }; 2571da177e4SLinus Torvalds 258d320c038STejun Heo struct workqueue_struct *system_wq __read_mostly; 259d320c038STejun Heo struct workqueue_struct *system_long_wq __read_mostly; 260d320c038STejun Heo struct workqueue_struct *system_nrt_wq __read_mostly; 261f3421797STejun Heo struct workqueue_struct *system_unbound_wq __read_mostly; 26224d51addSTejun Heo struct workqueue_struct *system_freezable_wq __read_mostly; 26362d3c543SAlan Stern struct workqueue_struct *system_nrt_freezable_wq __read_mostly; 264d320c038STejun Heo EXPORT_SYMBOL_GPL(system_wq); 265d320c038STejun Heo EXPORT_SYMBOL_GPL(system_long_wq); 266d320c038STejun Heo EXPORT_SYMBOL_GPL(system_nrt_wq); 267f3421797STejun Heo EXPORT_SYMBOL_GPL(system_unbound_wq); 26824d51addSTejun Heo EXPORT_SYMBOL_GPL(system_freezable_wq); 26962d3c543SAlan Stern EXPORT_SYMBOL_GPL(system_nrt_freezable_wq); 270d320c038STejun Heo 27197bd2347STejun Heo #define CREATE_TRACE_POINTS 27297bd2347STejun Heo #include <trace/events/workqueue.h> 27397bd2347STejun Heo 274db7bccf4STejun Heo #define for_each_busy_worker(worker, i, pos, gcwq) \ 275db7bccf4STejun Heo for (i = 0; i < BUSY_WORKER_HASH_SIZE; i++) \ 276db7bccf4STejun Heo hlist_for_each_entry(worker, pos, &gcwq->busy_hash[i], hentry) 277db7bccf4STejun Heo 278f3421797STejun Heo static inline int __next_gcwq_cpu(int cpu, const struct cpumask *mask, 279f3421797STejun Heo unsigned int sw) 280f3421797STejun Heo { 281f3421797STejun Heo if (cpu < nr_cpu_ids) { 282f3421797STejun Heo if (sw & 1) { 283f3421797STejun Heo cpu = cpumask_next(cpu, mask); 284f3421797STejun Heo if (cpu < nr_cpu_ids) 285f3421797STejun Heo return cpu; 286f3421797STejun Heo } 287f3421797STejun Heo if (sw & 2) 288f3421797STejun Heo return WORK_CPU_UNBOUND; 289f3421797STejun Heo } 290f3421797STejun Heo return WORK_CPU_NONE; 291f3421797STejun Heo } 292f3421797STejun Heo 293f3421797STejun Heo static inline int __next_wq_cpu(int cpu, const struct cpumask *mask, 294f3421797STejun Heo struct workqueue_struct *wq) 295f3421797STejun Heo { 296f3421797STejun Heo return __next_gcwq_cpu(cpu, mask, !(wq->flags & WQ_UNBOUND) ? 1 : 2); 297f3421797STejun Heo } 298f3421797STejun Heo 29909884951STejun Heo /* 30009884951STejun Heo * CPU iterators 30109884951STejun Heo * 30209884951STejun Heo * An extra gcwq is defined for an invalid cpu number 30309884951STejun Heo * (WORK_CPU_UNBOUND) to host workqueues which are not bound to any 30409884951STejun Heo * specific CPU. The following iterators are similar to 30509884951STejun Heo * for_each_*_cpu() iterators but also considers the unbound gcwq. 30609884951STejun Heo * 30709884951STejun Heo * for_each_gcwq_cpu() : possible CPUs + WORK_CPU_UNBOUND 30809884951STejun Heo * for_each_online_gcwq_cpu() : online CPUs + WORK_CPU_UNBOUND 30909884951STejun Heo * for_each_cwq_cpu() : possible CPUs for bound workqueues, 31009884951STejun Heo * WORK_CPU_UNBOUND for unbound workqueues 31109884951STejun Heo */ 312f3421797STejun Heo #define for_each_gcwq_cpu(cpu) \ 313f3421797STejun Heo for ((cpu) = __next_gcwq_cpu(-1, cpu_possible_mask, 3); \ 314f3421797STejun Heo (cpu) < WORK_CPU_NONE; \ 315f3421797STejun Heo (cpu) = __next_gcwq_cpu((cpu), cpu_possible_mask, 3)) 316f3421797STejun Heo 317f3421797STejun Heo #define for_each_online_gcwq_cpu(cpu) \ 318f3421797STejun Heo for ((cpu) = __next_gcwq_cpu(-1, cpu_online_mask, 3); \ 319f3421797STejun Heo (cpu) < WORK_CPU_NONE; \ 320f3421797STejun Heo (cpu) = __next_gcwq_cpu((cpu), cpu_online_mask, 3)) 321f3421797STejun Heo 322f3421797STejun Heo #define for_each_cwq_cpu(cpu, wq) \ 323f3421797STejun Heo for ((cpu) = __next_wq_cpu(-1, cpu_possible_mask, (wq)); \ 324f3421797STejun Heo (cpu) < WORK_CPU_NONE; \ 325f3421797STejun Heo (cpu) = __next_wq_cpu((cpu), cpu_possible_mask, (wq))) 326f3421797STejun Heo 327dc186ad7SThomas Gleixner #ifdef CONFIG_DEBUG_OBJECTS_WORK 328dc186ad7SThomas Gleixner 329dc186ad7SThomas Gleixner static struct debug_obj_descr work_debug_descr; 330dc186ad7SThomas Gleixner 33199777288SStanislaw Gruszka static void *work_debug_hint(void *addr) 33299777288SStanislaw Gruszka { 33399777288SStanislaw Gruszka return ((struct work_struct *) addr)->func; 33499777288SStanislaw Gruszka } 33599777288SStanislaw Gruszka 336dc186ad7SThomas Gleixner /* 337dc186ad7SThomas Gleixner * fixup_init is called when: 338dc186ad7SThomas Gleixner * - an active object is initialized 339dc186ad7SThomas Gleixner */ 340dc186ad7SThomas Gleixner static int work_fixup_init(void *addr, enum debug_obj_state state) 341dc186ad7SThomas Gleixner { 342dc186ad7SThomas Gleixner struct work_struct *work = addr; 343dc186ad7SThomas Gleixner 344dc186ad7SThomas Gleixner switch (state) { 345dc186ad7SThomas Gleixner case ODEBUG_STATE_ACTIVE: 346dc186ad7SThomas Gleixner cancel_work_sync(work); 347dc186ad7SThomas Gleixner debug_object_init(work, &work_debug_descr); 348dc186ad7SThomas Gleixner return 1; 349dc186ad7SThomas Gleixner default: 350dc186ad7SThomas Gleixner return 0; 351dc186ad7SThomas Gleixner } 352dc186ad7SThomas Gleixner } 353dc186ad7SThomas Gleixner 354dc186ad7SThomas Gleixner /* 355dc186ad7SThomas Gleixner * fixup_activate is called when: 356dc186ad7SThomas Gleixner * - an active object is activated 357dc186ad7SThomas Gleixner * - an unknown object is activated (might be a statically initialized object) 358dc186ad7SThomas Gleixner */ 359dc186ad7SThomas Gleixner static int work_fixup_activate(void *addr, enum debug_obj_state state) 360dc186ad7SThomas Gleixner { 361dc186ad7SThomas Gleixner struct work_struct *work = addr; 362dc186ad7SThomas Gleixner 363dc186ad7SThomas Gleixner switch (state) { 364dc186ad7SThomas Gleixner 365dc186ad7SThomas Gleixner case ODEBUG_STATE_NOTAVAILABLE: 366dc186ad7SThomas Gleixner /* 367dc186ad7SThomas Gleixner * This is not really a fixup. The work struct was 368dc186ad7SThomas Gleixner * statically initialized. We just make sure that it 369dc186ad7SThomas Gleixner * is tracked in the object tracker. 370dc186ad7SThomas Gleixner */ 37122df02bbSTejun Heo if (test_bit(WORK_STRUCT_STATIC_BIT, work_data_bits(work))) { 372dc186ad7SThomas Gleixner debug_object_init(work, &work_debug_descr); 373dc186ad7SThomas Gleixner debug_object_activate(work, &work_debug_descr); 374dc186ad7SThomas Gleixner return 0; 375dc186ad7SThomas Gleixner } 376dc186ad7SThomas Gleixner WARN_ON_ONCE(1); 377dc186ad7SThomas Gleixner return 0; 378dc186ad7SThomas Gleixner 379dc186ad7SThomas Gleixner case ODEBUG_STATE_ACTIVE: 380dc186ad7SThomas Gleixner WARN_ON(1); 381dc186ad7SThomas Gleixner 382dc186ad7SThomas Gleixner default: 383dc186ad7SThomas Gleixner return 0; 384dc186ad7SThomas Gleixner } 385dc186ad7SThomas Gleixner } 386dc186ad7SThomas Gleixner 387dc186ad7SThomas Gleixner /* 388dc186ad7SThomas Gleixner * fixup_free is called when: 389dc186ad7SThomas Gleixner * - an active object is freed 390dc186ad7SThomas Gleixner */ 391dc186ad7SThomas Gleixner static int work_fixup_free(void *addr, enum debug_obj_state state) 392dc186ad7SThomas Gleixner { 393dc186ad7SThomas Gleixner struct work_struct *work = addr; 394dc186ad7SThomas Gleixner 395dc186ad7SThomas Gleixner switch (state) { 396dc186ad7SThomas Gleixner case ODEBUG_STATE_ACTIVE: 397dc186ad7SThomas Gleixner cancel_work_sync(work); 398dc186ad7SThomas Gleixner debug_object_free(work, &work_debug_descr); 399dc186ad7SThomas Gleixner return 1; 400dc186ad7SThomas Gleixner default: 401dc186ad7SThomas Gleixner return 0; 402dc186ad7SThomas Gleixner } 403dc186ad7SThomas Gleixner } 404dc186ad7SThomas Gleixner 405dc186ad7SThomas Gleixner static struct debug_obj_descr work_debug_descr = { 406dc186ad7SThomas Gleixner .name = "work_struct", 40799777288SStanislaw Gruszka .debug_hint = work_debug_hint, 408dc186ad7SThomas Gleixner .fixup_init = work_fixup_init, 409dc186ad7SThomas Gleixner .fixup_activate = work_fixup_activate, 410dc186ad7SThomas Gleixner .fixup_free = work_fixup_free, 411dc186ad7SThomas Gleixner }; 412dc186ad7SThomas Gleixner 413dc186ad7SThomas Gleixner static inline void debug_work_activate(struct work_struct *work) 414dc186ad7SThomas Gleixner { 415dc186ad7SThomas Gleixner debug_object_activate(work, &work_debug_descr); 416dc186ad7SThomas Gleixner } 417dc186ad7SThomas Gleixner 418dc186ad7SThomas Gleixner static inline void debug_work_deactivate(struct work_struct *work) 419dc186ad7SThomas Gleixner { 420dc186ad7SThomas Gleixner debug_object_deactivate(work, &work_debug_descr); 421dc186ad7SThomas Gleixner } 422dc186ad7SThomas Gleixner 423dc186ad7SThomas Gleixner void __init_work(struct work_struct *work, int onstack) 424dc186ad7SThomas Gleixner { 425dc186ad7SThomas Gleixner if (onstack) 426dc186ad7SThomas Gleixner debug_object_init_on_stack(work, &work_debug_descr); 427dc186ad7SThomas Gleixner else 428dc186ad7SThomas Gleixner debug_object_init(work, &work_debug_descr); 429dc186ad7SThomas Gleixner } 430dc186ad7SThomas Gleixner EXPORT_SYMBOL_GPL(__init_work); 431dc186ad7SThomas Gleixner 432dc186ad7SThomas Gleixner void destroy_work_on_stack(struct work_struct *work) 433dc186ad7SThomas Gleixner { 434dc186ad7SThomas Gleixner debug_object_free(work, &work_debug_descr); 435dc186ad7SThomas Gleixner } 436dc186ad7SThomas Gleixner EXPORT_SYMBOL_GPL(destroy_work_on_stack); 437dc186ad7SThomas Gleixner 438dc186ad7SThomas Gleixner #else 439dc186ad7SThomas Gleixner static inline void debug_work_activate(struct work_struct *work) { } 440dc186ad7SThomas Gleixner static inline void debug_work_deactivate(struct work_struct *work) { } 441dc186ad7SThomas Gleixner #endif 442dc186ad7SThomas Gleixner 44395402b38SGautham R Shenoy /* Serializes the accesses to the list of workqueues. */ 44495402b38SGautham R Shenoy static DEFINE_SPINLOCK(workqueue_lock); 4451da177e4SLinus Torvalds static LIST_HEAD(workqueues); 446a0a1a5fdSTejun Heo static bool workqueue_freezing; /* W: have wqs started freezing? */ 4471da177e4SLinus Torvalds 44814441960SOleg Nesterov /* 449e22bee78STejun Heo * The almighty global cpu workqueues. nr_running is the only field 450e22bee78STejun Heo * which is expected to be used frequently by other cpus via 451e22bee78STejun Heo * try_to_wake_up(). Put it in a separate cacheline. 45214441960SOleg Nesterov */ 4538b03ae3cSTejun Heo static DEFINE_PER_CPU(struct global_cwq, global_cwq); 454e22bee78STejun Heo static DEFINE_PER_CPU_SHARED_ALIGNED(atomic_t, gcwq_nr_running); 455f756d5e2SNathan Lynch 456f3421797STejun Heo /* 457f3421797STejun Heo * Global cpu workqueue and nr_running counter for unbound gcwq. The 458f3421797STejun Heo * gcwq is always online, has GCWQ_DISASSOCIATED set, and all its 459f3421797STejun Heo * workers have WORKER_UNBOUND set. 460f3421797STejun Heo */ 461f3421797STejun Heo static struct global_cwq unbound_global_cwq; 462f3421797STejun Heo static atomic_t unbound_gcwq_nr_running = ATOMIC_INIT(0); /* always 0 */ 463f3421797STejun Heo 464c34056a3STejun Heo static int worker_thread(void *__worker); 4651da177e4SLinus Torvalds 4668b03ae3cSTejun Heo static struct global_cwq *get_gcwq(unsigned int cpu) 4671da177e4SLinus Torvalds { 468f3421797STejun Heo if (cpu != WORK_CPU_UNBOUND) 4698b03ae3cSTejun Heo return &per_cpu(global_cwq, cpu); 470f3421797STejun Heo else 471f3421797STejun Heo return &unbound_global_cwq; 4721da177e4SLinus Torvalds } 4731da177e4SLinus Torvalds 47463d95a91STejun Heo static atomic_t *get_pool_nr_running(struct worker_pool *pool) 475b1f4ec17SOleg Nesterov { 47663d95a91STejun Heo int cpu = pool->gcwq->cpu; 47763d95a91STejun Heo 478f3421797STejun Heo if (cpu != WORK_CPU_UNBOUND) 479e22bee78STejun Heo return &per_cpu(gcwq_nr_running, cpu); 480f3421797STejun Heo else 481f3421797STejun Heo return &unbound_gcwq_nr_running; 482b1f4ec17SOleg Nesterov } 483b1f4ec17SOleg Nesterov 4844690c4abSTejun Heo static struct cpu_workqueue_struct *get_cwq(unsigned int cpu, 4854690c4abSTejun Heo struct workqueue_struct *wq) 486a848e3b6SOleg Nesterov { 487f3421797STejun Heo if (!(wq->flags & WQ_UNBOUND)) { 488e06ffa1eSLai Jiangshan if (likely(cpu < nr_cpu_ids)) 489bdbc5dd7STejun Heo return per_cpu_ptr(wq->cpu_wq.pcpu, cpu); 490f3421797STejun Heo } else if (likely(cpu == WORK_CPU_UNBOUND)) 491f3421797STejun Heo return wq->cpu_wq.single; 492f3421797STejun Heo return NULL; 493f3421797STejun Heo } 494a848e3b6SOleg Nesterov 49573f53c4aSTejun Heo static unsigned int work_color_to_flags(int color) 49673f53c4aSTejun Heo { 49773f53c4aSTejun Heo return color << WORK_STRUCT_COLOR_SHIFT; 49873f53c4aSTejun Heo } 49973f53c4aSTejun Heo 50073f53c4aSTejun Heo static int get_work_color(struct work_struct *work) 50173f53c4aSTejun Heo { 50273f53c4aSTejun Heo return (*work_data_bits(work) >> WORK_STRUCT_COLOR_SHIFT) & 50373f53c4aSTejun Heo ((1 << WORK_STRUCT_COLOR_BITS) - 1); 50473f53c4aSTejun Heo } 50573f53c4aSTejun Heo 50673f53c4aSTejun Heo static int work_next_color(int color) 50773f53c4aSTejun Heo { 50873f53c4aSTejun Heo return (color + 1) % WORK_NR_COLORS; 5091da177e4SLinus Torvalds } 5101da177e4SLinus Torvalds 5114594bf15SDavid Howells /* 512e120153dSTejun Heo * A work's data points to the cwq with WORK_STRUCT_CWQ set while the 513e120153dSTejun Heo * work is on queue. Once execution starts, WORK_STRUCT_CWQ is 514e120153dSTejun Heo * cleared and the work data contains the cpu number it was last on. 5157a22ad75STejun Heo * 5167a22ad75STejun Heo * set_work_{cwq|cpu}() and clear_work_data() can be used to set the 5177a22ad75STejun Heo * cwq, cpu or clear work->data. These functions should only be 5187a22ad75STejun Heo * called while the work is owned - ie. while the PENDING bit is set. 5197a22ad75STejun Heo * 5207a22ad75STejun Heo * get_work_[g]cwq() can be used to obtain the gcwq or cwq 5217a22ad75STejun Heo * corresponding to a work. gcwq is available once the work has been 5227a22ad75STejun Heo * queued anywhere after initialization. cwq is available only from 5237a22ad75STejun Heo * queueing until execution starts. 5244594bf15SDavid Howells */ 5257a22ad75STejun Heo static inline void set_work_data(struct work_struct *work, unsigned long data, 5267a22ad75STejun Heo unsigned long flags) 5277a22ad75STejun Heo { 5287a22ad75STejun Heo BUG_ON(!work_pending(work)); 5297a22ad75STejun Heo atomic_long_set(&work->data, data | flags | work_static(work)); 5307a22ad75STejun Heo } 5317a22ad75STejun Heo 5327a22ad75STejun Heo static void set_work_cwq(struct work_struct *work, 5334690c4abSTejun Heo struct cpu_workqueue_struct *cwq, 5344690c4abSTejun Heo unsigned long extra_flags) 535365970a1SDavid Howells { 5367a22ad75STejun Heo set_work_data(work, (unsigned long)cwq, 537e120153dSTejun Heo WORK_STRUCT_PENDING | WORK_STRUCT_CWQ | extra_flags); 538365970a1SDavid Howells } 539365970a1SDavid Howells 5407a22ad75STejun Heo static void set_work_cpu(struct work_struct *work, unsigned int cpu) 5414d707b9fSOleg Nesterov { 5427a22ad75STejun Heo set_work_data(work, cpu << WORK_STRUCT_FLAG_BITS, WORK_STRUCT_PENDING); 5434d707b9fSOleg Nesterov } 5444d707b9fSOleg Nesterov 5457a22ad75STejun Heo static void clear_work_data(struct work_struct *work) 546365970a1SDavid Howells { 5477a22ad75STejun Heo set_work_data(work, WORK_STRUCT_NO_CPU, 0); 5487a22ad75STejun Heo } 5497a22ad75STejun Heo 5507a22ad75STejun Heo static struct cpu_workqueue_struct *get_work_cwq(struct work_struct *work) 5517a22ad75STejun Heo { 552e120153dSTejun Heo unsigned long data = atomic_long_read(&work->data); 5537a22ad75STejun Heo 554e120153dSTejun Heo if (data & WORK_STRUCT_CWQ) 555e120153dSTejun Heo return (void *)(data & WORK_STRUCT_WQ_DATA_MASK); 556e120153dSTejun Heo else 557e120153dSTejun Heo return NULL; 5587a22ad75STejun Heo } 5597a22ad75STejun Heo 5607a22ad75STejun Heo static struct global_cwq *get_work_gcwq(struct work_struct *work) 5617a22ad75STejun Heo { 562e120153dSTejun Heo unsigned long data = atomic_long_read(&work->data); 5637a22ad75STejun Heo unsigned int cpu; 5647a22ad75STejun Heo 565e120153dSTejun Heo if (data & WORK_STRUCT_CWQ) 566e120153dSTejun Heo return ((struct cpu_workqueue_struct *) 567bd7bdd43STejun Heo (data & WORK_STRUCT_WQ_DATA_MASK))->pool->gcwq; 5687a22ad75STejun Heo 5697a22ad75STejun Heo cpu = data >> WORK_STRUCT_FLAG_BITS; 570bdbc5dd7STejun Heo if (cpu == WORK_CPU_NONE) 5717a22ad75STejun Heo return NULL; 5727a22ad75STejun Heo 573f3421797STejun Heo BUG_ON(cpu >= nr_cpu_ids && cpu != WORK_CPU_UNBOUND); 5747a22ad75STejun Heo return get_gcwq(cpu); 575365970a1SDavid Howells } 576365970a1SDavid Howells 577e22bee78STejun Heo /* 578e22bee78STejun Heo * Policy functions. These define the policies on how the global 579e22bee78STejun Heo * worker pool is managed. Unless noted otherwise, these functions 580e22bee78STejun Heo * assume that they're being called with gcwq->lock held. 581e22bee78STejun Heo */ 582e22bee78STejun Heo 58363d95a91STejun Heo static bool __need_more_worker(struct worker_pool *pool) 584649027d7STejun Heo { 58563d95a91STejun Heo return !atomic_read(get_pool_nr_running(pool)) || 58663d95a91STejun Heo pool->gcwq->flags & GCWQ_HIGHPRI_PENDING; 587649027d7STejun Heo } 588649027d7STejun Heo 589e22bee78STejun Heo /* 590e22bee78STejun Heo * Need to wake up a worker? Called from anything but currently 591e22bee78STejun Heo * running workers. 592974271c4STejun Heo * 593974271c4STejun Heo * Note that, because unbound workers never contribute to nr_running, this 594974271c4STejun Heo * function will always return %true for unbound gcwq as long as the 595974271c4STejun Heo * worklist isn't empty. 596e22bee78STejun Heo */ 59763d95a91STejun Heo static bool need_more_worker(struct worker_pool *pool) 598e22bee78STejun Heo { 59963d95a91STejun Heo return !list_empty(&pool->worklist) && __need_more_worker(pool); 600e22bee78STejun Heo } 601e22bee78STejun Heo 602e22bee78STejun Heo /* Can I start working? Called from busy but !running workers. */ 60363d95a91STejun Heo static bool may_start_working(struct worker_pool *pool) 604e22bee78STejun Heo { 60563d95a91STejun Heo return pool->nr_idle; 606e22bee78STejun Heo } 607e22bee78STejun Heo 608e22bee78STejun Heo /* Do I need to keep working? Called from currently running workers. */ 60963d95a91STejun Heo static bool keep_working(struct worker_pool *pool) 610e22bee78STejun Heo { 61163d95a91STejun Heo atomic_t *nr_running = get_pool_nr_running(pool); 612e22bee78STejun Heo 61363d95a91STejun Heo return !list_empty(&pool->worklist) && 61430310045STejun Heo (atomic_read(nr_running) <= 1 || 61563d95a91STejun Heo pool->gcwq->flags & GCWQ_HIGHPRI_PENDING); 616e22bee78STejun Heo } 617e22bee78STejun Heo 618e22bee78STejun Heo /* Do we need a new worker? Called from manager. */ 61963d95a91STejun Heo static bool need_to_create_worker(struct worker_pool *pool) 620e22bee78STejun Heo { 62163d95a91STejun Heo return need_more_worker(pool) && !may_start_working(pool); 622e22bee78STejun Heo } 623e22bee78STejun Heo 624e22bee78STejun Heo /* Do I need to be the manager? */ 62563d95a91STejun Heo static bool need_to_manage_workers(struct worker_pool *pool) 626e22bee78STejun Heo { 62763d95a91STejun Heo return need_to_create_worker(pool) || 62863d95a91STejun Heo pool->gcwq->flags & GCWQ_MANAGE_WORKERS; 629e22bee78STejun Heo } 630e22bee78STejun Heo 631e22bee78STejun Heo /* Do we have too many workers and should some go away? */ 63263d95a91STejun Heo static bool too_many_workers(struct worker_pool *pool) 633e22bee78STejun Heo { 63463d95a91STejun Heo bool managing = pool->gcwq->flags & GCWQ_MANAGING_WORKERS; 63563d95a91STejun Heo int nr_idle = pool->nr_idle + managing; /* manager is considered idle */ 63663d95a91STejun Heo int nr_busy = pool->nr_workers - nr_idle; 637e22bee78STejun Heo 638e22bee78STejun Heo return nr_idle > 2 && (nr_idle - 2) * MAX_IDLE_WORKERS_RATIO >= nr_busy; 639e22bee78STejun Heo } 640e22bee78STejun Heo 641e22bee78STejun Heo /* 642e22bee78STejun Heo * Wake up functions. 643e22bee78STejun Heo */ 644e22bee78STejun Heo 6457e11629dSTejun Heo /* Return the first worker. Safe with preemption disabled */ 64663d95a91STejun Heo static struct worker *first_worker(struct worker_pool *pool) 6477e11629dSTejun Heo { 64863d95a91STejun Heo if (unlikely(list_empty(&pool->idle_list))) 6497e11629dSTejun Heo return NULL; 6507e11629dSTejun Heo 65163d95a91STejun Heo return list_first_entry(&pool->idle_list, struct worker, entry); 6527e11629dSTejun Heo } 6537e11629dSTejun Heo 6547e11629dSTejun Heo /** 6557e11629dSTejun Heo * wake_up_worker - wake up an idle worker 65663d95a91STejun Heo * @pool: worker pool to wake worker from 6577e11629dSTejun Heo * 65863d95a91STejun Heo * Wake up the first idle worker of @pool. 6597e11629dSTejun Heo * 6607e11629dSTejun Heo * CONTEXT: 6617e11629dSTejun Heo * spin_lock_irq(gcwq->lock). 6627e11629dSTejun Heo */ 66363d95a91STejun Heo static void wake_up_worker(struct worker_pool *pool) 6647e11629dSTejun Heo { 66563d95a91STejun Heo struct worker *worker = first_worker(pool); 6667e11629dSTejun Heo 6677e11629dSTejun Heo if (likely(worker)) 6687e11629dSTejun Heo wake_up_process(worker->task); 6697e11629dSTejun Heo } 6707e11629dSTejun Heo 6714690c4abSTejun Heo /** 672e22bee78STejun Heo * wq_worker_waking_up - a worker is waking up 673e22bee78STejun Heo * @task: task waking up 674e22bee78STejun Heo * @cpu: CPU @task is waking up to 675e22bee78STejun Heo * 676e22bee78STejun Heo * This function is called during try_to_wake_up() when a worker is 677e22bee78STejun Heo * being awoken. 678e22bee78STejun Heo * 679e22bee78STejun Heo * CONTEXT: 680e22bee78STejun Heo * spin_lock_irq(rq->lock) 681e22bee78STejun Heo */ 682e22bee78STejun Heo void wq_worker_waking_up(struct task_struct *task, unsigned int cpu) 683e22bee78STejun Heo { 684e22bee78STejun Heo struct worker *worker = kthread_data(task); 685e22bee78STejun Heo 6862d64672eSSteven Rostedt if (!(worker->flags & WORKER_NOT_RUNNING)) 68763d95a91STejun Heo atomic_inc(get_pool_nr_running(worker->pool)); 688e22bee78STejun Heo } 689e22bee78STejun Heo 690e22bee78STejun Heo /** 691e22bee78STejun Heo * wq_worker_sleeping - a worker is going to sleep 692e22bee78STejun Heo * @task: task going to sleep 693e22bee78STejun Heo * @cpu: CPU in question, must be the current CPU number 694e22bee78STejun Heo * 695e22bee78STejun Heo * This function is called during schedule() when a busy worker is 696e22bee78STejun Heo * going to sleep. Worker on the same cpu can be woken up by 697e22bee78STejun Heo * returning pointer to its task. 698e22bee78STejun Heo * 699e22bee78STejun Heo * CONTEXT: 700e22bee78STejun Heo * spin_lock_irq(rq->lock) 701e22bee78STejun Heo * 702e22bee78STejun Heo * RETURNS: 703e22bee78STejun Heo * Worker task on @cpu to wake up, %NULL if none. 704e22bee78STejun Heo */ 705e22bee78STejun Heo struct task_struct *wq_worker_sleeping(struct task_struct *task, 706e22bee78STejun Heo unsigned int cpu) 707e22bee78STejun Heo { 708e22bee78STejun Heo struct worker *worker = kthread_data(task), *to_wakeup = NULL; 709bd7bdd43STejun Heo struct worker_pool *pool = worker->pool; 71063d95a91STejun Heo atomic_t *nr_running = get_pool_nr_running(pool); 711e22bee78STejun Heo 7122d64672eSSteven Rostedt if (worker->flags & WORKER_NOT_RUNNING) 713e22bee78STejun Heo return NULL; 714e22bee78STejun Heo 715e22bee78STejun Heo /* this can only happen on the local cpu */ 716e22bee78STejun Heo BUG_ON(cpu != raw_smp_processor_id()); 717e22bee78STejun Heo 718e22bee78STejun Heo /* 719e22bee78STejun Heo * The counterpart of the following dec_and_test, implied mb, 720e22bee78STejun Heo * worklist not empty test sequence is in insert_work(). 721e22bee78STejun Heo * Please read comment there. 722e22bee78STejun Heo * 723e22bee78STejun Heo * NOT_RUNNING is clear. This means that trustee is not in 724e22bee78STejun Heo * charge and we're running on the local cpu w/ rq lock held 725e22bee78STejun Heo * and preemption disabled, which in turn means that none else 726e22bee78STejun Heo * could be manipulating idle_list, so dereferencing idle_list 727e22bee78STejun Heo * without gcwq lock is safe. 728e22bee78STejun Heo */ 729bd7bdd43STejun Heo if (atomic_dec_and_test(nr_running) && !list_empty(&pool->worklist)) 73063d95a91STejun Heo to_wakeup = first_worker(pool); 731e22bee78STejun Heo return to_wakeup ? to_wakeup->task : NULL; 732e22bee78STejun Heo } 733e22bee78STejun Heo 734e22bee78STejun Heo /** 735e22bee78STejun Heo * worker_set_flags - set worker flags and adjust nr_running accordingly 736cb444766STejun Heo * @worker: self 737d302f017STejun Heo * @flags: flags to set 738d302f017STejun Heo * @wakeup: wakeup an idle worker if necessary 739d302f017STejun Heo * 740e22bee78STejun Heo * Set @flags in @worker->flags and adjust nr_running accordingly. If 741e22bee78STejun Heo * nr_running becomes zero and @wakeup is %true, an idle worker is 742e22bee78STejun Heo * woken up. 743d302f017STejun Heo * 744cb444766STejun Heo * CONTEXT: 745cb444766STejun Heo * spin_lock_irq(gcwq->lock) 746d302f017STejun Heo */ 747d302f017STejun Heo static inline void worker_set_flags(struct worker *worker, unsigned int flags, 748d302f017STejun Heo bool wakeup) 749d302f017STejun Heo { 750bd7bdd43STejun Heo struct worker_pool *pool = worker->pool; 751e22bee78STejun Heo 752cb444766STejun Heo WARN_ON_ONCE(worker->task != current); 753cb444766STejun Heo 754e22bee78STejun Heo /* 755e22bee78STejun Heo * If transitioning into NOT_RUNNING, adjust nr_running and 756e22bee78STejun Heo * wake up an idle worker as necessary if requested by 757e22bee78STejun Heo * @wakeup. 758e22bee78STejun Heo */ 759e22bee78STejun Heo if ((flags & WORKER_NOT_RUNNING) && 760e22bee78STejun Heo !(worker->flags & WORKER_NOT_RUNNING)) { 76163d95a91STejun Heo atomic_t *nr_running = get_pool_nr_running(pool); 762e22bee78STejun Heo 763e22bee78STejun Heo if (wakeup) { 764e22bee78STejun Heo if (atomic_dec_and_test(nr_running) && 765bd7bdd43STejun Heo !list_empty(&pool->worklist)) 76663d95a91STejun Heo wake_up_worker(pool); 767e22bee78STejun Heo } else 768e22bee78STejun Heo atomic_dec(nr_running); 769e22bee78STejun Heo } 770e22bee78STejun Heo 771d302f017STejun Heo worker->flags |= flags; 772d302f017STejun Heo } 773d302f017STejun Heo 774d302f017STejun Heo /** 775e22bee78STejun Heo * worker_clr_flags - clear worker flags and adjust nr_running accordingly 776cb444766STejun Heo * @worker: self 777d302f017STejun Heo * @flags: flags to clear 778d302f017STejun Heo * 779e22bee78STejun Heo * Clear @flags in @worker->flags and adjust nr_running accordingly. 780d302f017STejun Heo * 781cb444766STejun Heo * CONTEXT: 782cb444766STejun Heo * spin_lock_irq(gcwq->lock) 783d302f017STejun Heo */ 784d302f017STejun Heo static inline void worker_clr_flags(struct worker *worker, unsigned int flags) 785d302f017STejun Heo { 78663d95a91STejun Heo struct worker_pool *pool = worker->pool; 787e22bee78STejun Heo unsigned int oflags = worker->flags; 788e22bee78STejun Heo 789cb444766STejun Heo WARN_ON_ONCE(worker->task != current); 790cb444766STejun Heo 791d302f017STejun Heo worker->flags &= ~flags; 792e22bee78STejun Heo 79342c025f3STejun Heo /* 79442c025f3STejun Heo * If transitioning out of NOT_RUNNING, increment nr_running. Note 79542c025f3STejun Heo * that the nested NOT_RUNNING is not a noop. NOT_RUNNING is mask 79642c025f3STejun Heo * of multiple flags, not a single flag. 79742c025f3STejun Heo */ 798e22bee78STejun Heo if ((flags & WORKER_NOT_RUNNING) && (oflags & WORKER_NOT_RUNNING)) 799e22bee78STejun Heo if (!(worker->flags & WORKER_NOT_RUNNING)) 80063d95a91STejun Heo atomic_inc(get_pool_nr_running(pool)); 801d302f017STejun Heo } 802d302f017STejun Heo 803d302f017STejun Heo /** 804c8e55f36STejun Heo * busy_worker_head - return the busy hash head for a work 805c8e55f36STejun Heo * @gcwq: gcwq of interest 806c8e55f36STejun Heo * @work: work to be hashed 807c8e55f36STejun Heo * 808c8e55f36STejun Heo * Return hash head of @gcwq for @work. 809c8e55f36STejun Heo * 810c8e55f36STejun Heo * CONTEXT: 811c8e55f36STejun Heo * spin_lock_irq(gcwq->lock). 812c8e55f36STejun Heo * 813c8e55f36STejun Heo * RETURNS: 814c8e55f36STejun Heo * Pointer to the hash head. 815c8e55f36STejun Heo */ 816c8e55f36STejun Heo static struct hlist_head *busy_worker_head(struct global_cwq *gcwq, 817c8e55f36STejun Heo struct work_struct *work) 818c8e55f36STejun Heo { 819c8e55f36STejun Heo const int base_shift = ilog2(sizeof(struct work_struct)); 820c8e55f36STejun Heo unsigned long v = (unsigned long)work; 821c8e55f36STejun Heo 822c8e55f36STejun Heo /* simple shift and fold hash, do we need something better? */ 823c8e55f36STejun Heo v >>= base_shift; 824c8e55f36STejun Heo v += v >> BUSY_WORKER_HASH_ORDER; 825c8e55f36STejun Heo v &= BUSY_WORKER_HASH_MASK; 826c8e55f36STejun Heo 827c8e55f36STejun Heo return &gcwq->busy_hash[v]; 828c8e55f36STejun Heo } 829c8e55f36STejun Heo 830c8e55f36STejun Heo /** 8318cca0eeaSTejun Heo * __find_worker_executing_work - find worker which is executing a work 8328cca0eeaSTejun Heo * @gcwq: gcwq of interest 8338cca0eeaSTejun Heo * @bwh: hash head as returned by busy_worker_head() 8348cca0eeaSTejun Heo * @work: work to find worker for 8358cca0eeaSTejun Heo * 8368cca0eeaSTejun Heo * Find a worker which is executing @work on @gcwq. @bwh should be 8378cca0eeaSTejun Heo * the hash head obtained by calling busy_worker_head() with the same 8388cca0eeaSTejun Heo * work. 8398cca0eeaSTejun Heo * 8408cca0eeaSTejun Heo * CONTEXT: 8418cca0eeaSTejun Heo * spin_lock_irq(gcwq->lock). 8428cca0eeaSTejun Heo * 8438cca0eeaSTejun Heo * RETURNS: 8448cca0eeaSTejun Heo * Pointer to worker which is executing @work if found, NULL 8458cca0eeaSTejun Heo * otherwise. 8468cca0eeaSTejun Heo */ 8478cca0eeaSTejun Heo static struct worker *__find_worker_executing_work(struct global_cwq *gcwq, 8488cca0eeaSTejun Heo struct hlist_head *bwh, 8498cca0eeaSTejun Heo struct work_struct *work) 8508cca0eeaSTejun Heo { 8518cca0eeaSTejun Heo struct worker *worker; 8528cca0eeaSTejun Heo struct hlist_node *tmp; 8538cca0eeaSTejun Heo 8548cca0eeaSTejun Heo hlist_for_each_entry(worker, tmp, bwh, hentry) 8558cca0eeaSTejun Heo if (worker->current_work == work) 8568cca0eeaSTejun Heo return worker; 8578cca0eeaSTejun Heo return NULL; 8588cca0eeaSTejun Heo } 8598cca0eeaSTejun Heo 8608cca0eeaSTejun Heo /** 8618cca0eeaSTejun Heo * find_worker_executing_work - find worker which is executing a work 8628cca0eeaSTejun Heo * @gcwq: gcwq of interest 8638cca0eeaSTejun Heo * @work: work to find worker for 8648cca0eeaSTejun Heo * 8658cca0eeaSTejun Heo * Find a worker which is executing @work on @gcwq. This function is 8668cca0eeaSTejun Heo * identical to __find_worker_executing_work() except that this 8678cca0eeaSTejun Heo * function calculates @bwh itself. 8688cca0eeaSTejun Heo * 8698cca0eeaSTejun Heo * CONTEXT: 8708cca0eeaSTejun Heo * spin_lock_irq(gcwq->lock). 8718cca0eeaSTejun Heo * 8728cca0eeaSTejun Heo * RETURNS: 8738cca0eeaSTejun Heo * Pointer to worker which is executing @work if found, NULL 8748cca0eeaSTejun Heo * otherwise. 8758cca0eeaSTejun Heo */ 8768cca0eeaSTejun Heo static struct worker *find_worker_executing_work(struct global_cwq *gcwq, 8778cca0eeaSTejun Heo struct work_struct *work) 8788cca0eeaSTejun Heo { 8798cca0eeaSTejun Heo return __find_worker_executing_work(gcwq, busy_worker_head(gcwq, work), 8808cca0eeaSTejun Heo work); 8818cca0eeaSTejun Heo } 8828cca0eeaSTejun Heo 8838cca0eeaSTejun Heo /** 88463d95a91STejun Heo * pool_determine_ins_pos - find insertion position 88563d95a91STejun Heo * @pool: pool of interest 886649027d7STejun Heo * @cwq: cwq a work is being queued for 887649027d7STejun Heo * 88863d95a91STejun Heo * A work for @cwq is about to be queued on @pool, determine insertion 889649027d7STejun Heo * position for the work. If @cwq is for HIGHPRI wq, the work is 890649027d7STejun Heo * queued at the head of the queue but in FIFO order with respect to 891649027d7STejun Heo * other HIGHPRI works; otherwise, at the end of the queue. This 89263d95a91STejun Heo * function also sets GCWQ_HIGHPRI_PENDING flag to hint @pool that 893649027d7STejun Heo * there are HIGHPRI works pending. 894649027d7STejun Heo * 895649027d7STejun Heo * CONTEXT: 896649027d7STejun Heo * spin_lock_irq(gcwq->lock). 897649027d7STejun Heo * 898649027d7STejun Heo * RETURNS: 899649027d7STejun Heo * Pointer to inserstion position. 900649027d7STejun Heo */ 90163d95a91STejun Heo static inline struct list_head *pool_determine_ins_pos(struct worker_pool *pool, 9021da177e4SLinus Torvalds struct cpu_workqueue_struct *cwq) 9031da177e4SLinus Torvalds { 904649027d7STejun Heo struct work_struct *twork; 9051da177e4SLinus Torvalds 906649027d7STejun Heo if (likely(!(cwq->wq->flags & WQ_HIGHPRI))) 90763d95a91STejun Heo return &pool->worklist; 9081da177e4SLinus Torvalds 90963d95a91STejun Heo list_for_each_entry(twork, &pool->worklist, entry) { 910649027d7STejun Heo struct cpu_workqueue_struct *tcwq = get_work_cwq(twork); 911649027d7STejun Heo 912649027d7STejun Heo if (!(tcwq->wq->flags & WQ_HIGHPRI)) 913649027d7STejun Heo break; 9141da177e4SLinus Torvalds } 9151da177e4SLinus Torvalds 91663d95a91STejun Heo pool->gcwq->flags |= GCWQ_HIGHPRI_PENDING; 917649027d7STejun Heo return &twork->entry; 918649027d7STejun Heo } 919649027d7STejun Heo 920649027d7STejun Heo /** 9217e11629dSTejun Heo * insert_work - insert a work into gcwq 9224690c4abSTejun Heo * @cwq: cwq @work belongs to 9234690c4abSTejun Heo * @work: work to insert 9244690c4abSTejun Heo * @head: insertion point 9254690c4abSTejun Heo * @extra_flags: extra WORK_STRUCT_* flags to set 9264690c4abSTejun Heo * 9277e11629dSTejun Heo * Insert @work which belongs to @cwq into @gcwq after @head. 9287e11629dSTejun Heo * @extra_flags is or'd to work_struct flags. 9294690c4abSTejun Heo * 9304690c4abSTejun Heo * CONTEXT: 9318b03ae3cSTejun Heo * spin_lock_irq(gcwq->lock). 9321da177e4SLinus Torvalds */ 933b89deed3SOleg Nesterov static void insert_work(struct cpu_workqueue_struct *cwq, 9344690c4abSTejun Heo struct work_struct *work, struct list_head *head, 9354690c4abSTejun Heo unsigned int extra_flags) 936b89deed3SOleg Nesterov { 93763d95a91STejun Heo struct worker_pool *pool = cwq->pool; 938e1d8aa9fSFrederic Weisbecker 9394690c4abSTejun Heo /* we own @work, set data and link */ 9407a22ad75STejun Heo set_work_cwq(work, cwq, extra_flags); 9414690c4abSTejun Heo 9426e84d644SOleg Nesterov /* 9436e84d644SOleg Nesterov * Ensure that we get the right work->data if we see the 9446e84d644SOleg Nesterov * result of list_add() below, see try_to_grab_pending(). 9456e84d644SOleg Nesterov */ 9466e84d644SOleg Nesterov smp_wmb(); 9474690c4abSTejun Heo 9481a4d9b0aSOleg Nesterov list_add_tail(&work->entry, head); 949e22bee78STejun Heo 950e22bee78STejun Heo /* 951e22bee78STejun Heo * Ensure either worker_sched_deactivated() sees the above 952e22bee78STejun Heo * list_add_tail() or we see zero nr_running to avoid workers 953e22bee78STejun Heo * lying around lazily while there are works to be processed. 954e22bee78STejun Heo */ 955e22bee78STejun Heo smp_mb(); 956e22bee78STejun Heo 95763d95a91STejun Heo if (__need_more_worker(pool)) 95863d95a91STejun Heo wake_up_worker(pool); 959b89deed3SOleg Nesterov } 960b89deed3SOleg Nesterov 961c8efcc25STejun Heo /* 962c8efcc25STejun Heo * Test whether @work is being queued from another work executing on the 963c8efcc25STejun Heo * same workqueue. This is rather expensive and should only be used from 964c8efcc25STejun Heo * cold paths. 965c8efcc25STejun Heo */ 966c8efcc25STejun Heo static bool is_chained_work(struct workqueue_struct *wq) 967c8efcc25STejun Heo { 968c8efcc25STejun Heo unsigned long flags; 969c8efcc25STejun Heo unsigned int cpu; 970c8efcc25STejun Heo 971c8efcc25STejun Heo for_each_gcwq_cpu(cpu) { 972c8efcc25STejun Heo struct global_cwq *gcwq = get_gcwq(cpu); 973c8efcc25STejun Heo struct worker *worker; 974c8efcc25STejun Heo struct hlist_node *pos; 975c8efcc25STejun Heo int i; 976c8efcc25STejun Heo 977c8efcc25STejun Heo spin_lock_irqsave(&gcwq->lock, flags); 978c8efcc25STejun Heo for_each_busy_worker(worker, i, pos, gcwq) { 979c8efcc25STejun Heo if (worker->task != current) 980c8efcc25STejun Heo continue; 981c8efcc25STejun Heo spin_unlock_irqrestore(&gcwq->lock, flags); 982c8efcc25STejun Heo /* 983c8efcc25STejun Heo * I'm @worker, no locking necessary. See if @work 984c8efcc25STejun Heo * is headed to the same workqueue. 985c8efcc25STejun Heo */ 986c8efcc25STejun Heo return worker->current_cwq->wq == wq; 987c8efcc25STejun Heo } 988c8efcc25STejun Heo spin_unlock_irqrestore(&gcwq->lock, flags); 989c8efcc25STejun Heo } 990c8efcc25STejun Heo return false; 991c8efcc25STejun Heo } 992c8efcc25STejun Heo 9934690c4abSTejun Heo static void __queue_work(unsigned int cpu, struct workqueue_struct *wq, 9941da177e4SLinus Torvalds struct work_struct *work) 9951da177e4SLinus Torvalds { 996502ca9d8STejun Heo struct global_cwq *gcwq; 997502ca9d8STejun Heo struct cpu_workqueue_struct *cwq; 9981e19ffc6STejun Heo struct list_head *worklist; 9998a2e8e5dSTejun Heo unsigned int work_flags; 10001da177e4SLinus Torvalds unsigned long flags; 10011da177e4SLinus Torvalds 1002dc186ad7SThomas Gleixner debug_work_activate(work); 10031e19ffc6STejun Heo 1004c8efcc25STejun Heo /* if dying, only works from the same workqueue are allowed */ 10059c5a2ba7STejun Heo if (unlikely(wq->flags & WQ_DRAINING) && 1006c8efcc25STejun Heo WARN_ON_ONCE(!is_chained_work(wq))) 1007e41e704bSTejun Heo return; 1008e41e704bSTejun Heo 1009c7fc77f7STejun Heo /* determine gcwq to use */ 1010c7fc77f7STejun Heo if (!(wq->flags & WQ_UNBOUND)) { 1011c7fc77f7STejun Heo struct global_cwq *last_gcwq; 1012c7fc77f7STejun Heo 1013f3421797STejun Heo if (unlikely(cpu == WORK_CPU_UNBOUND)) 1014f3421797STejun Heo cpu = raw_smp_processor_id(); 1015f3421797STejun Heo 101618aa9effSTejun Heo /* 101718aa9effSTejun Heo * It's multi cpu. If @wq is non-reentrant and @work 101818aa9effSTejun Heo * was previously on a different cpu, it might still 101918aa9effSTejun Heo * be running there, in which case the work needs to 102018aa9effSTejun Heo * be queued on that cpu to guarantee non-reentrance. 102118aa9effSTejun Heo */ 1022502ca9d8STejun Heo gcwq = get_gcwq(cpu); 102318aa9effSTejun Heo if (wq->flags & WQ_NON_REENTRANT && 102418aa9effSTejun Heo (last_gcwq = get_work_gcwq(work)) && last_gcwq != gcwq) { 102518aa9effSTejun Heo struct worker *worker; 102618aa9effSTejun Heo 102718aa9effSTejun Heo spin_lock_irqsave(&last_gcwq->lock, flags); 102818aa9effSTejun Heo 102918aa9effSTejun Heo worker = find_worker_executing_work(last_gcwq, work); 103018aa9effSTejun Heo 103118aa9effSTejun Heo if (worker && worker->current_cwq->wq == wq) 103218aa9effSTejun Heo gcwq = last_gcwq; 103318aa9effSTejun Heo else { 103418aa9effSTejun Heo /* meh... not running there, queue here */ 103518aa9effSTejun Heo spin_unlock_irqrestore(&last_gcwq->lock, flags); 103618aa9effSTejun Heo spin_lock_irqsave(&gcwq->lock, flags); 103718aa9effSTejun Heo } 103818aa9effSTejun Heo } else 10398b03ae3cSTejun Heo spin_lock_irqsave(&gcwq->lock, flags); 1040f3421797STejun Heo } else { 1041f3421797STejun Heo gcwq = get_gcwq(WORK_CPU_UNBOUND); 1042f3421797STejun Heo spin_lock_irqsave(&gcwq->lock, flags); 1043502ca9d8STejun Heo } 1044502ca9d8STejun Heo 1045502ca9d8STejun Heo /* gcwq determined, get cwq and queue */ 1046502ca9d8STejun Heo cwq = get_cwq(gcwq->cpu, wq); 1047cdadf009STejun Heo trace_workqueue_queue_work(cpu, cwq, work); 1048502ca9d8STejun Heo 1049f5b2552bSDan Carpenter if (WARN_ON(!list_empty(&work->entry))) { 1050f5b2552bSDan Carpenter spin_unlock_irqrestore(&gcwq->lock, flags); 1051f5b2552bSDan Carpenter return; 1052f5b2552bSDan Carpenter } 10531e19ffc6STejun Heo 105473f53c4aSTejun Heo cwq->nr_in_flight[cwq->work_color]++; 10558a2e8e5dSTejun Heo work_flags = work_color_to_flags(cwq->work_color); 10561e19ffc6STejun Heo 10571e19ffc6STejun Heo if (likely(cwq->nr_active < cwq->max_active)) { 1058cdadf009STejun Heo trace_workqueue_activate_work(work); 10591e19ffc6STejun Heo cwq->nr_active++; 106063d95a91STejun Heo worklist = pool_determine_ins_pos(cwq->pool, cwq); 10618a2e8e5dSTejun Heo } else { 10628a2e8e5dSTejun Heo work_flags |= WORK_STRUCT_DELAYED; 10631e19ffc6STejun Heo worklist = &cwq->delayed_works; 10648a2e8e5dSTejun Heo } 10651e19ffc6STejun Heo 10668a2e8e5dSTejun Heo insert_work(cwq, work, worklist, work_flags); 10671e19ffc6STejun Heo 10688b03ae3cSTejun Heo spin_unlock_irqrestore(&gcwq->lock, flags); 10691da177e4SLinus Torvalds } 10701da177e4SLinus Torvalds 10710fcb78c2SRolf Eike Beer /** 10720fcb78c2SRolf Eike Beer * queue_work - queue work on a workqueue 10730fcb78c2SRolf Eike Beer * @wq: workqueue to use 10740fcb78c2SRolf Eike Beer * @work: work to queue 10750fcb78c2SRolf Eike Beer * 1076057647fcSAlan Stern * Returns 0 if @work was already on a queue, non-zero otherwise. 10771da177e4SLinus Torvalds * 107800dfcaf7SOleg Nesterov * We queue the work to the CPU on which it was submitted, but if the CPU dies 107900dfcaf7SOleg Nesterov * it can be processed by another CPU. 10801da177e4SLinus Torvalds */ 10817ad5b3a5SHarvey Harrison int queue_work(struct workqueue_struct *wq, struct work_struct *work) 10821da177e4SLinus Torvalds { 1083ef1ca236SOleg Nesterov int ret; 10841da177e4SLinus Torvalds 1085ef1ca236SOleg Nesterov ret = queue_work_on(get_cpu(), wq, work); 1086a848e3b6SOleg Nesterov put_cpu(); 1087ef1ca236SOleg Nesterov 10881da177e4SLinus Torvalds return ret; 10891da177e4SLinus Torvalds } 1090ae90dd5dSDave Jones EXPORT_SYMBOL_GPL(queue_work); 10911da177e4SLinus Torvalds 1092c1a220e7SZhang Rui /** 1093c1a220e7SZhang Rui * queue_work_on - queue work on specific cpu 1094c1a220e7SZhang Rui * @cpu: CPU number to execute work on 1095c1a220e7SZhang Rui * @wq: workqueue to use 1096c1a220e7SZhang Rui * @work: work to queue 1097c1a220e7SZhang Rui * 1098c1a220e7SZhang Rui * Returns 0 if @work was already on a queue, non-zero otherwise. 1099c1a220e7SZhang Rui * 1100c1a220e7SZhang Rui * We queue the work to a specific CPU, the caller must ensure it 1101c1a220e7SZhang Rui * can't go away. 1102c1a220e7SZhang Rui */ 1103c1a220e7SZhang Rui int 1104c1a220e7SZhang Rui queue_work_on(int cpu, struct workqueue_struct *wq, struct work_struct *work) 1105c1a220e7SZhang Rui { 1106c1a220e7SZhang Rui int ret = 0; 1107c1a220e7SZhang Rui 110822df02bbSTejun Heo if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) { 11094690c4abSTejun Heo __queue_work(cpu, wq, work); 1110c1a220e7SZhang Rui ret = 1; 1111c1a220e7SZhang Rui } 1112c1a220e7SZhang Rui return ret; 1113c1a220e7SZhang Rui } 1114c1a220e7SZhang Rui EXPORT_SYMBOL_GPL(queue_work_on); 1115c1a220e7SZhang Rui 11166d141c3fSLi Zefan static void delayed_work_timer_fn(unsigned long __data) 11171da177e4SLinus Torvalds { 111852bad64dSDavid Howells struct delayed_work *dwork = (struct delayed_work *)__data; 11197a22ad75STejun Heo struct cpu_workqueue_struct *cwq = get_work_cwq(&dwork->work); 11201da177e4SLinus Torvalds 11214690c4abSTejun Heo __queue_work(smp_processor_id(), cwq->wq, &dwork->work); 11221da177e4SLinus Torvalds } 11231da177e4SLinus Torvalds 11240fcb78c2SRolf Eike Beer /** 11250fcb78c2SRolf Eike Beer * queue_delayed_work - queue work on a workqueue after delay 11260fcb78c2SRolf Eike Beer * @wq: workqueue to use 1127af9997e4SRandy Dunlap * @dwork: delayable work to queue 11280fcb78c2SRolf Eike Beer * @delay: number of jiffies to wait before queueing 11290fcb78c2SRolf Eike Beer * 1130057647fcSAlan Stern * Returns 0 if @work was already on a queue, non-zero otherwise. 11310fcb78c2SRolf Eike Beer */ 11327ad5b3a5SHarvey Harrison int queue_delayed_work(struct workqueue_struct *wq, 113352bad64dSDavid Howells struct delayed_work *dwork, unsigned long delay) 11341da177e4SLinus Torvalds { 113552bad64dSDavid Howells if (delay == 0) 113663bc0362SOleg Nesterov return queue_work(wq, &dwork->work); 11371da177e4SLinus Torvalds 113863bc0362SOleg Nesterov return queue_delayed_work_on(-1, wq, dwork, delay); 11391da177e4SLinus Torvalds } 1140ae90dd5dSDave Jones EXPORT_SYMBOL_GPL(queue_delayed_work); 11411da177e4SLinus Torvalds 11420fcb78c2SRolf Eike Beer /** 11430fcb78c2SRolf Eike Beer * queue_delayed_work_on - queue work on specific CPU after delay 11440fcb78c2SRolf Eike Beer * @cpu: CPU number to execute work on 11450fcb78c2SRolf Eike Beer * @wq: workqueue to use 1146af9997e4SRandy Dunlap * @dwork: work to queue 11470fcb78c2SRolf Eike Beer * @delay: number of jiffies to wait before queueing 11480fcb78c2SRolf Eike Beer * 1149057647fcSAlan Stern * Returns 0 if @work was already on a queue, non-zero otherwise. 11500fcb78c2SRolf Eike Beer */ 11517a6bc1cdSVenkatesh Pallipadi int queue_delayed_work_on(int cpu, struct workqueue_struct *wq, 115252bad64dSDavid Howells struct delayed_work *dwork, unsigned long delay) 11537a6bc1cdSVenkatesh Pallipadi { 11547a6bc1cdSVenkatesh Pallipadi int ret = 0; 115552bad64dSDavid Howells struct timer_list *timer = &dwork->timer; 115652bad64dSDavid Howells struct work_struct *work = &dwork->work; 11577a6bc1cdSVenkatesh Pallipadi 115822df02bbSTejun Heo if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) { 1159c7fc77f7STejun Heo unsigned int lcpu; 11607a22ad75STejun Heo 11617a6bc1cdSVenkatesh Pallipadi BUG_ON(timer_pending(timer)); 11627a6bc1cdSVenkatesh Pallipadi BUG_ON(!list_empty(&work->entry)); 11637a6bc1cdSVenkatesh Pallipadi 11648a3e77ccSAndrew Liu timer_stats_timer_set_start_info(&dwork->timer); 11658a3e77ccSAndrew Liu 11667a22ad75STejun Heo /* 11677a22ad75STejun Heo * This stores cwq for the moment, for the timer_fn. 11687a22ad75STejun Heo * Note that the work's gcwq is preserved to allow 11697a22ad75STejun Heo * reentrance detection for delayed works. 11707a22ad75STejun Heo */ 1171c7fc77f7STejun Heo if (!(wq->flags & WQ_UNBOUND)) { 1172c7fc77f7STejun Heo struct global_cwq *gcwq = get_work_gcwq(work); 1173c7fc77f7STejun Heo 1174c7fc77f7STejun Heo if (gcwq && gcwq->cpu != WORK_CPU_UNBOUND) 1175c7fc77f7STejun Heo lcpu = gcwq->cpu; 1176c7fc77f7STejun Heo else 1177c7fc77f7STejun Heo lcpu = raw_smp_processor_id(); 1178c7fc77f7STejun Heo } else 1179c7fc77f7STejun Heo lcpu = WORK_CPU_UNBOUND; 1180c7fc77f7STejun Heo 11817a22ad75STejun Heo set_work_cwq(work, get_cwq(lcpu, wq), 0); 1182c7fc77f7STejun Heo 11837a6bc1cdSVenkatesh Pallipadi timer->expires = jiffies + delay; 118452bad64dSDavid Howells timer->data = (unsigned long)dwork; 11857a6bc1cdSVenkatesh Pallipadi timer->function = delayed_work_timer_fn; 118663bc0362SOleg Nesterov 118763bc0362SOleg Nesterov if (unlikely(cpu >= 0)) 11887a6bc1cdSVenkatesh Pallipadi add_timer_on(timer, cpu); 118963bc0362SOleg Nesterov else 119063bc0362SOleg Nesterov add_timer(timer); 11917a6bc1cdSVenkatesh Pallipadi ret = 1; 11927a6bc1cdSVenkatesh Pallipadi } 11937a6bc1cdSVenkatesh Pallipadi return ret; 11947a6bc1cdSVenkatesh Pallipadi } 1195ae90dd5dSDave Jones EXPORT_SYMBOL_GPL(queue_delayed_work_on); 11961da177e4SLinus Torvalds 1197c8e55f36STejun Heo /** 1198c8e55f36STejun Heo * worker_enter_idle - enter idle state 1199c8e55f36STejun Heo * @worker: worker which is entering idle state 1200c8e55f36STejun Heo * 1201c8e55f36STejun Heo * @worker is entering idle state. Update stats and idle timer if 1202c8e55f36STejun Heo * necessary. 1203c8e55f36STejun Heo * 1204c8e55f36STejun Heo * LOCKING: 1205c8e55f36STejun Heo * spin_lock_irq(gcwq->lock). 1206c8e55f36STejun Heo */ 1207c8e55f36STejun Heo static void worker_enter_idle(struct worker *worker) 12081da177e4SLinus Torvalds { 1209bd7bdd43STejun Heo struct worker_pool *pool = worker->pool; 1210bd7bdd43STejun Heo struct global_cwq *gcwq = pool->gcwq; 1211c8e55f36STejun Heo 1212c8e55f36STejun Heo BUG_ON(worker->flags & WORKER_IDLE); 1213c8e55f36STejun Heo BUG_ON(!list_empty(&worker->entry) && 1214c8e55f36STejun Heo (worker->hentry.next || worker->hentry.pprev)); 1215c8e55f36STejun Heo 1216cb444766STejun Heo /* can't use worker_set_flags(), also called from start_worker() */ 1217cb444766STejun Heo worker->flags |= WORKER_IDLE; 1218bd7bdd43STejun Heo pool->nr_idle++; 1219e22bee78STejun Heo worker->last_active = jiffies; 1220c8e55f36STejun Heo 1221c8e55f36STejun Heo /* idle_list is LIFO */ 1222bd7bdd43STejun Heo list_add(&worker->entry, &pool->idle_list); 1223db7bccf4STejun Heo 1224e22bee78STejun Heo if (likely(!(worker->flags & WORKER_ROGUE))) { 122563d95a91STejun Heo if (too_many_workers(pool) && !timer_pending(&pool->idle_timer)) 1226bd7bdd43STejun Heo mod_timer(&pool->idle_timer, 1227e22bee78STejun Heo jiffies + IDLE_WORKER_TIMEOUT); 1228e22bee78STejun Heo } else 1229db7bccf4STejun Heo wake_up_all(&gcwq->trustee_wait); 1230cb444766STejun Heo 1231544ecf31STejun Heo /* 1232544ecf31STejun Heo * Sanity check nr_running. Because trustee releases gcwq->lock 1233544ecf31STejun Heo * between setting %WORKER_ROGUE and zapping nr_running, the 1234544ecf31STejun Heo * warning may trigger spuriously. Check iff trustee is idle. 1235544ecf31STejun Heo */ 1236544ecf31STejun Heo WARN_ON_ONCE(gcwq->trustee_state == TRUSTEE_DONE && 1237bd7bdd43STejun Heo pool->nr_workers == pool->nr_idle && 123863d95a91STejun Heo atomic_read(get_pool_nr_running(pool))); 1239c8e55f36STejun Heo } 1240c8e55f36STejun Heo 1241c8e55f36STejun Heo /** 1242c8e55f36STejun Heo * worker_leave_idle - leave idle state 1243c8e55f36STejun Heo * @worker: worker which is leaving idle state 1244c8e55f36STejun Heo * 1245c8e55f36STejun Heo * @worker is leaving idle state. Update stats. 1246c8e55f36STejun Heo * 1247c8e55f36STejun Heo * LOCKING: 1248c8e55f36STejun Heo * spin_lock_irq(gcwq->lock). 1249c8e55f36STejun Heo */ 1250c8e55f36STejun Heo static void worker_leave_idle(struct worker *worker) 1251c8e55f36STejun Heo { 1252bd7bdd43STejun Heo struct worker_pool *pool = worker->pool; 1253c8e55f36STejun Heo 1254c8e55f36STejun Heo BUG_ON(!(worker->flags & WORKER_IDLE)); 1255d302f017STejun Heo worker_clr_flags(worker, WORKER_IDLE); 1256bd7bdd43STejun Heo pool->nr_idle--; 1257c8e55f36STejun Heo list_del_init(&worker->entry); 1258c8e55f36STejun Heo } 1259c8e55f36STejun Heo 1260e22bee78STejun Heo /** 1261e22bee78STejun Heo * worker_maybe_bind_and_lock - bind worker to its cpu if possible and lock gcwq 1262e22bee78STejun Heo * @worker: self 1263e22bee78STejun Heo * 1264e22bee78STejun Heo * Works which are scheduled while the cpu is online must at least be 1265e22bee78STejun Heo * scheduled to a worker which is bound to the cpu so that if they are 1266e22bee78STejun Heo * flushed from cpu callbacks while cpu is going down, they are 1267e22bee78STejun Heo * guaranteed to execute on the cpu. 1268e22bee78STejun Heo * 1269e22bee78STejun Heo * This function is to be used by rogue workers and rescuers to bind 1270e22bee78STejun Heo * themselves to the target cpu and may race with cpu going down or 1271e22bee78STejun Heo * coming online. kthread_bind() can't be used because it may put the 1272e22bee78STejun Heo * worker to already dead cpu and set_cpus_allowed_ptr() can't be used 1273e22bee78STejun Heo * verbatim as it's best effort and blocking and gcwq may be 1274e22bee78STejun Heo * [dis]associated in the meantime. 1275e22bee78STejun Heo * 1276e22bee78STejun Heo * This function tries set_cpus_allowed() and locks gcwq and verifies 1277e22bee78STejun Heo * the binding against GCWQ_DISASSOCIATED which is set during 1278e22bee78STejun Heo * CPU_DYING and cleared during CPU_ONLINE, so if the worker enters 1279e22bee78STejun Heo * idle state or fetches works without dropping lock, it can guarantee 1280e22bee78STejun Heo * the scheduling requirement described in the first paragraph. 1281e22bee78STejun Heo * 1282e22bee78STejun Heo * CONTEXT: 1283e22bee78STejun Heo * Might sleep. Called without any lock but returns with gcwq->lock 1284e22bee78STejun Heo * held. 1285e22bee78STejun Heo * 1286e22bee78STejun Heo * RETURNS: 1287e22bee78STejun Heo * %true if the associated gcwq is online (@worker is successfully 1288e22bee78STejun Heo * bound), %false if offline. 1289e22bee78STejun Heo */ 1290e22bee78STejun Heo static bool worker_maybe_bind_and_lock(struct worker *worker) 1291972fa1c5SNamhyung Kim __acquires(&gcwq->lock) 1292e22bee78STejun Heo { 1293bd7bdd43STejun Heo struct global_cwq *gcwq = worker->pool->gcwq; 1294e22bee78STejun Heo struct task_struct *task = worker->task; 1295e22bee78STejun Heo 1296e22bee78STejun Heo while (true) { 1297e22bee78STejun Heo /* 1298e22bee78STejun Heo * The following call may fail, succeed or succeed 1299e22bee78STejun Heo * without actually migrating the task to the cpu if 1300e22bee78STejun Heo * it races with cpu hotunplug operation. Verify 1301e22bee78STejun Heo * against GCWQ_DISASSOCIATED. 1302e22bee78STejun Heo */ 1303f3421797STejun Heo if (!(gcwq->flags & GCWQ_DISASSOCIATED)) 1304e22bee78STejun Heo set_cpus_allowed_ptr(task, get_cpu_mask(gcwq->cpu)); 1305e22bee78STejun Heo 1306e22bee78STejun Heo spin_lock_irq(&gcwq->lock); 1307e22bee78STejun Heo if (gcwq->flags & GCWQ_DISASSOCIATED) 1308e22bee78STejun Heo return false; 1309e22bee78STejun Heo if (task_cpu(task) == gcwq->cpu && 1310e22bee78STejun Heo cpumask_equal(¤t->cpus_allowed, 1311e22bee78STejun Heo get_cpu_mask(gcwq->cpu))) 1312e22bee78STejun Heo return true; 1313e22bee78STejun Heo spin_unlock_irq(&gcwq->lock); 1314e22bee78STejun Heo 13155035b20fSTejun Heo /* 13165035b20fSTejun Heo * We've raced with CPU hot[un]plug. Give it a breather 13175035b20fSTejun Heo * and retry migration. cond_resched() is required here; 13185035b20fSTejun Heo * otherwise, we might deadlock against cpu_stop trying to 13195035b20fSTejun Heo * bring down the CPU on non-preemptive kernel. 13205035b20fSTejun Heo */ 1321e22bee78STejun Heo cpu_relax(); 13225035b20fSTejun Heo cond_resched(); 1323e22bee78STejun Heo } 1324e22bee78STejun Heo } 1325e22bee78STejun Heo 1326e22bee78STejun Heo /* 1327e22bee78STejun Heo * Function for worker->rebind_work used to rebind rogue busy workers 1328e22bee78STejun Heo * to the associated cpu which is coming back online. This is 1329e22bee78STejun Heo * scheduled by cpu up but can race with other cpu hotplug operations 1330e22bee78STejun Heo * and may be executed twice without intervening cpu down. 1331e22bee78STejun Heo */ 1332e22bee78STejun Heo static void worker_rebind_fn(struct work_struct *work) 1333e22bee78STejun Heo { 1334e22bee78STejun Heo struct worker *worker = container_of(work, struct worker, rebind_work); 1335bd7bdd43STejun Heo struct global_cwq *gcwq = worker->pool->gcwq; 1336e22bee78STejun Heo 1337e22bee78STejun Heo if (worker_maybe_bind_and_lock(worker)) 1338e22bee78STejun Heo worker_clr_flags(worker, WORKER_REBIND); 1339e22bee78STejun Heo 1340e22bee78STejun Heo spin_unlock_irq(&gcwq->lock); 1341e22bee78STejun Heo } 1342e22bee78STejun Heo 1343c34056a3STejun Heo static struct worker *alloc_worker(void) 1344c34056a3STejun Heo { 1345c34056a3STejun Heo struct worker *worker; 1346c34056a3STejun Heo 1347c34056a3STejun Heo worker = kzalloc(sizeof(*worker), GFP_KERNEL); 1348c8e55f36STejun Heo if (worker) { 1349c8e55f36STejun Heo INIT_LIST_HEAD(&worker->entry); 1350affee4b2STejun Heo INIT_LIST_HEAD(&worker->scheduled); 1351e22bee78STejun Heo INIT_WORK(&worker->rebind_work, worker_rebind_fn); 1352e22bee78STejun Heo /* on creation a worker is in !idle && prep state */ 1353e22bee78STejun Heo worker->flags = WORKER_PREP; 1354c8e55f36STejun Heo } 1355c34056a3STejun Heo return worker; 1356c34056a3STejun Heo } 1357c34056a3STejun Heo 1358c34056a3STejun Heo /** 1359c34056a3STejun Heo * create_worker - create a new workqueue worker 136063d95a91STejun Heo * @pool: pool the new worker will belong to 1361c34056a3STejun Heo * @bind: whether to set affinity to @cpu or not 1362c34056a3STejun Heo * 136363d95a91STejun Heo * Create a new worker which is bound to @pool. The returned worker 1364c34056a3STejun Heo * can be started by calling start_worker() or destroyed using 1365c34056a3STejun Heo * destroy_worker(). 1366c34056a3STejun Heo * 1367c34056a3STejun Heo * CONTEXT: 1368c34056a3STejun Heo * Might sleep. Does GFP_KERNEL allocations. 1369c34056a3STejun Heo * 1370c34056a3STejun Heo * RETURNS: 1371c34056a3STejun Heo * Pointer to the newly created worker. 1372c34056a3STejun Heo */ 137363d95a91STejun Heo static struct worker *create_worker(struct worker_pool *pool, bool bind) 1374c34056a3STejun Heo { 137563d95a91STejun Heo struct global_cwq *gcwq = pool->gcwq; 1376f3421797STejun Heo bool on_unbound_cpu = gcwq->cpu == WORK_CPU_UNBOUND; 1377c34056a3STejun Heo struct worker *worker = NULL; 1378f3421797STejun Heo int id = -1; 1379c34056a3STejun Heo 13808b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 1381bd7bdd43STejun Heo while (ida_get_new(&pool->worker_ida, &id)) { 13828b03ae3cSTejun Heo spin_unlock_irq(&gcwq->lock); 1383bd7bdd43STejun Heo if (!ida_pre_get(&pool->worker_ida, GFP_KERNEL)) 1384c34056a3STejun Heo goto fail; 13858b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 1386c34056a3STejun Heo } 13878b03ae3cSTejun Heo spin_unlock_irq(&gcwq->lock); 1388c34056a3STejun Heo 1389c34056a3STejun Heo worker = alloc_worker(); 1390c34056a3STejun Heo if (!worker) 1391c34056a3STejun Heo goto fail; 1392c34056a3STejun Heo 1393bd7bdd43STejun Heo worker->pool = pool; 1394c34056a3STejun Heo worker->id = id; 1395c34056a3STejun Heo 1396f3421797STejun Heo if (!on_unbound_cpu) 139794dcf29aSEric Dumazet worker->task = kthread_create_on_node(worker_thread, 139894dcf29aSEric Dumazet worker, 139994dcf29aSEric Dumazet cpu_to_node(gcwq->cpu), 1400f3421797STejun Heo "kworker/%u:%d", gcwq->cpu, id); 1401f3421797STejun Heo else 1402f3421797STejun Heo worker->task = kthread_create(worker_thread, worker, 1403f3421797STejun Heo "kworker/u:%d", id); 1404c34056a3STejun Heo if (IS_ERR(worker->task)) 1405c34056a3STejun Heo goto fail; 1406c34056a3STejun Heo 1407db7bccf4STejun Heo /* 1408db7bccf4STejun Heo * A rogue worker will become a regular one if CPU comes 1409db7bccf4STejun Heo * online later on. Make sure every worker has 1410db7bccf4STejun Heo * PF_THREAD_BOUND set. 1411db7bccf4STejun Heo */ 1412f3421797STejun Heo if (bind && !on_unbound_cpu) 14138b03ae3cSTejun Heo kthread_bind(worker->task, gcwq->cpu); 1414f3421797STejun Heo else { 1415db7bccf4STejun Heo worker->task->flags |= PF_THREAD_BOUND; 1416f3421797STejun Heo if (on_unbound_cpu) 1417f3421797STejun Heo worker->flags |= WORKER_UNBOUND; 1418f3421797STejun Heo } 1419c34056a3STejun Heo 1420c34056a3STejun Heo return worker; 1421c34056a3STejun Heo fail: 1422c34056a3STejun Heo if (id >= 0) { 14238b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 1424bd7bdd43STejun Heo ida_remove(&pool->worker_ida, id); 14258b03ae3cSTejun Heo spin_unlock_irq(&gcwq->lock); 1426c34056a3STejun Heo } 1427c34056a3STejun Heo kfree(worker); 1428c34056a3STejun Heo return NULL; 1429c34056a3STejun Heo } 1430c34056a3STejun Heo 1431c34056a3STejun Heo /** 1432c34056a3STejun Heo * start_worker - start a newly created worker 1433c34056a3STejun Heo * @worker: worker to start 1434c34056a3STejun Heo * 1435c8e55f36STejun Heo * Make the gcwq aware of @worker and start it. 1436c34056a3STejun Heo * 1437c34056a3STejun Heo * CONTEXT: 14388b03ae3cSTejun Heo * spin_lock_irq(gcwq->lock). 1439c34056a3STejun Heo */ 1440c34056a3STejun Heo static void start_worker(struct worker *worker) 1441c34056a3STejun Heo { 1442cb444766STejun Heo worker->flags |= WORKER_STARTED; 1443bd7bdd43STejun Heo worker->pool->nr_workers++; 1444c8e55f36STejun Heo worker_enter_idle(worker); 1445c34056a3STejun Heo wake_up_process(worker->task); 1446c34056a3STejun Heo } 1447c34056a3STejun Heo 1448c34056a3STejun Heo /** 1449c34056a3STejun Heo * destroy_worker - destroy a workqueue worker 1450c34056a3STejun Heo * @worker: worker to be destroyed 1451c34056a3STejun Heo * 1452c8e55f36STejun Heo * Destroy @worker and adjust @gcwq stats accordingly. 1453c8e55f36STejun Heo * 1454c8e55f36STejun Heo * CONTEXT: 1455c8e55f36STejun Heo * spin_lock_irq(gcwq->lock) which is released and regrabbed. 1456c34056a3STejun Heo */ 1457c34056a3STejun Heo static void destroy_worker(struct worker *worker) 1458c34056a3STejun Heo { 1459bd7bdd43STejun Heo struct worker_pool *pool = worker->pool; 1460bd7bdd43STejun Heo struct global_cwq *gcwq = pool->gcwq; 1461c34056a3STejun Heo int id = worker->id; 1462c34056a3STejun Heo 1463c34056a3STejun Heo /* sanity check frenzy */ 1464c34056a3STejun Heo BUG_ON(worker->current_work); 1465affee4b2STejun Heo BUG_ON(!list_empty(&worker->scheduled)); 1466c34056a3STejun Heo 1467c8e55f36STejun Heo if (worker->flags & WORKER_STARTED) 1468bd7bdd43STejun Heo pool->nr_workers--; 1469c8e55f36STejun Heo if (worker->flags & WORKER_IDLE) 1470bd7bdd43STejun Heo pool->nr_idle--; 1471c8e55f36STejun Heo 1472c8e55f36STejun Heo list_del_init(&worker->entry); 1473cb444766STejun Heo worker->flags |= WORKER_DIE; 1474c8e55f36STejun Heo 1475c8e55f36STejun Heo spin_unlock_irq(&gcwq->lock); 1476c8e55f36STejun Heo 1477c34056a3STejun Heo kthread_stop(worker->task); 1478c34056a3STejun Heo kfree(worker); 1479c34056a3STejun Heo 14808b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 1481bd7bdd43STejun Heo ida_remove(&pool->worker_ida, id); 1482c34056a3STejun Heo } 1483c34056a3STejun Heo 148463d95a91STejun Heo static void idle_worker_timeout(unsigned long __pool) 1485e22bee78STejun Heo { 148663d95a91STejun Heo struct worker_pool *pool = (void *)__pool; 148763d95a91STejun Heo struct global_cwq *gcwq = pool->gcwq; 1488e22bee78STejun Heo 1489e22bee78STejun Heo spin_lock_irq(&gcwq->lock); 1490e22bee78STejun Heo 149163d95a91STejun Heo if (too_many_workers(pool)) { 1492e22bee78STejun Heo struct worker *worker; 1493e22bee78STejun Heo unsigned long expires; 1494e22bee78STejun Heo 1495e22bee78STejun Heo /* idle_list is kept in LIFO order, check the last one */ 149663d95a91STejun Heo worker = list_entry(pool->idle_list.prev, struct worker, entry); 1497e22bee78STejun Heo expires = worker->last_active + IDLE_WORKER_TIMEOUT; 1498e22bee78STejun Heo 1499e22bee78STejun Heo if (time_before(jiffies, expires)) 150063d95a91STejun Heo mod_timer(&pool->idle_timer, expires); 1501e22bee78STejun Heo else { 1502e22bee78STejun Heo /* it's been idle for too long, wake up manager */ 1503e22bee78STejun Heo gcwq->flags |= GCWQ_MANAGE_WORKERS; 150463d95a91STejun Heo wake_up_worker(pool); 1505e22bee78STejun Heo } 1506e22bee78STejun Heo } 1507e22bee78STejun Heo 1508e22bee78STejun Heo spin_unlock_irq(&gcwq->lock); 1509e22bee78STejun Heo } 1510e22bee78STejun Heo 1511e22bee78STejun Heo static bool send_mayday(struct work_struct *work) 1512e22bee78STejun Heo { 1513e22bee78STejun Heo struct cpu_workqueue_struct *cwq = get_work_cwq(work); 1514e22bee78STejun Heo struct workqueue_struct *wq = cwq->wq; 1515f3421797STejun Heo unsigned int cpu; 1516e22bee78STejun Heo 1517e22bee78STejun Heo if (!(wq->flags & WQ_RESCUER)) 1518e22bee78STejun Heo return false; 1519e22bee78STejun Heo 1520e22bee78STejun Heo /* mayday mayday mayday */ 1521bd7bdd43STejun Heo cpu = cwq->pool->gcwq->cpu; 1522f3421797STejun Heo /* WORK_CPU_UNBOUND can't be set in cpumask, use cpu 0 instead */ 1523f3421797STejun Heo if (cpu == WORK_CPU_UNBOUND) 1524f3421797STejun Heo cpu = 0; 1525f2e005aaSTejun Heo if (!mayday_test_and_set_cpu(cpu, wq->mayday_mask)) 1526e22bee78STejun Heo wake_up_process(wq->rescuer->task); 1527e22bee78STejun Heo return true; 1528e22bee78STejun Heo } 1529e22bee78STejun Heo 153063d95a91STejun Heo static void gcwq_mayday_timeout(unsigned long __pool) 1531e22bee78STejun Heo { 153263d95a91STejun Heo struct worker_pool *pool = (void *)__pool; 153363d95a91STejun Heo struct global_cwq *gcwq = pool->gcwq; 1534e22bee78STejun Heo struct work_struct *work; 1535e22bee78STejun Heo 1536e22bee78STejun Heo spin_lock_irq(&gcwq->lock); 1537e22bee78STejun Heo 153863d95a91STejun Heo if (need_to_create_worker(pool)) { 1539e22bee78STejun Heo /* 1540e22bee78STejun Heo * We've been trying to create a new worker but 1541e22bee78STejun Heo * haven't been successful. We might be hitting an 1542e22bee78STejun Heo * allocation deadlock. Send distress signals to 1543e22bee78STejun Heo * rescuers. 1544e22bee78STejun Heo */ 154563d95a91STejun Heo list_for_each_entry(work, &pool->worklist, entry) 1546e22bee78STejun Heo send_mayday(work); 1547e22bee78STejun Heo } 1548e22bee78STejun Heo 1549e22bee78STejun Heo spin_unlock_irq(&gcwq->lock); 1550e22bee78STejun Heo 155163d95a91STejun Heo mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INTERVAL); 1552e22bee78STejun Heo } 1553e22bee78STejun Heo 1554e22bee78STejun Heo /** 1555e22bee78STejun Heo * maybe_create_worker - create a new worker if necessary 155663d95a91STejun Heo * @pool: pool to create a new worker for 1557e22bee78STejun Heo * 155863d95a91STejun Heo * Create a new worker for @pool if necessary. @pool is guaranteed to 1559e22bee78STejun Heo * have at least one idle worker on return from this function. If 1560e22bee78STejun Heo * creating a new worker takes longer than MAYDAY_INTERVAL, mayday is 156163d95a91STejun Heo * sent to all rescuers with works scheduled on @pool to resolve 1562e22bee78STejun Heo * possible allocation deadlock. 1563e22bee78STejun Heo * 1564e22bee78STejun Heo * On return, need_to_create_worker() is guaranteed to be false and 1565e22bee78STejun Heo * may_start_working() true. 1566e22bee78STejun Heo * 1567e22bee78STejun Heo * LOCKING: 1568e22bee78STejun Heo * spin_lock_irq(gcwq->lock) which may be released and regrabbed 1569e22bee78STejun Heo * multiple times. Does GFP_KERNEL allocations. Called only from 1570e22bee78STejun Heo * manager. 1571e22bee78STejun Heo * 1572e22bee78STejun Heo * RETURNS: 1573e22bee78STejun Heo * false if no action was taken and gcwq->lock stayed locked, true 1574e22bee78STejun Heo * otherwise. 1575e22bee78STejun Heo */ 157663d95a91STejun Heo static bool maybe_create_worker(struct worker_pool *pool) 157706bd6ebfSNamhyung Kim __releases(&gcwq->lock) 157806bd6ebfSNamhyung Kim __acquires(&gcwq->lock) 1579e22bee78STejun Heo { 158063d95a91STejun Heo struct global_cwq *gcwq = pool->gcwq; 158163d95a91STejun Heo 158263d95a91STejun Heo if (!need_to_create_worker(pool)) 1583e22bee78STejun Heo return false; 1584e22bee78STejun Heo restart: 15859f9c2364STejun Heo spin_unlock_irq(&gcwq->lock); 15869f9c2364STejun Heo 1587e22bee78STejun Heo /* if we don't make progress in MAYDAY_INITIAL_TIMEOUT, call for help */ 158863d95a91STejun Heo mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INITIAL_TIMEOUT); 1589e22bee78STejun Heo 1590e22bee78STejun Heo while (true) { 1591e22bee78STejun Heo struct worker *worker; 1592e22bee78STejun Heo 159363d95a91STejun Heo worker = create_worker(pool, true); 1594e22bee78STejun Heo if (worker) { 159563d95a91STejun Heo del_timer_sync(&pool->mayday_timer); 1596e22bee78STejun Heo spin_lock_irq(&gcwq->lock); 1597e22bee78STejun Heo start_worker(worker); 159863d95a91STejun Heo BUG_ON(need_to_create_worker(pool)); 1599e22bee78STejun Heo return true; 1600e22bee78STejun Heo } 1601e22bee78STejun Heo 160263d95a91STejun Heo if (!need_to_create_worker(pool)) 1603e22bee78STejun Heo break; 1604e22bee78STejun Heo 1605e22bee78STejun Heo __set_current_state(TASK_INTERRUPTIBLE); 1606e22bee78STejun Heo schedule_timeout(CREATE_COOLDOWN); 16079f9c2364STejun Heo 160863d95a91STejun Heo if (!need_to_create_worker(pool)) 1609e22bee78STejun Heo break; 1610e22bee78STejun Heo } 1611e22bee78STejun Heo 161263d95a91STejun Heo del_timer_sync(&pool->mayday_timer); 1613e22bee78STejun Heo spin_lock_irq(&gcwq->lock); 161463d95a91STejun Heo if (need_to_create_worker(pool)) 1615e22bee78STejun Heo goto restart; 1616e22bee78STejun Heo return true; 1617e22bee78STejun Heo } 1618e22bee78STejun Heo 1619e22bee78STejun Heo /** 1620e22bee78STejun Heo * maybe_destroy_worker - destroy workers which have been idle for a while 162163d95a91STejun Heo * @pool: pool to destroy workers for 1622e22bee78STejun Heo * 162363d95a91STejun Heo * Destroy @pool workers which have been idle for longer than 1624e22bee78STejun Heo * IDLE_WORKER_TIMEOUT. 1625e22bee78STejun Heo * 1626e22bee78STejun Heo * LOCKING: 1627e22bee78STejun Heo * spin_lock_irq(gcwq->lock) which may be released and regrabbed 1628e22bee78STejun Heo * multiple times. Called only from manager. 1629e22bee78STejun Heo * 1630e22bee78STejun Heo * RETURNS: 1631e22bee78STejun Heo * false if no action was taken and gcwq->lock stayed locked, true 1632e22bee78STejun Heo * otherwise. 1633e22bee78STejun Heo */ 163463d95a91STejun Heo static bool maybe_destroy_workers(struct worker_pool *pool) 1635e22bee78STejun Heo { 1636e22bee78STejun Heo bool ret = false; 1637e22bee78STejun Heo 163863d95a91STejun Heo while (too_many_workers(pool)) { 1639e22bee78STejun Heo struct worker *worker; 1640e22bee78STejun Heo unsigned long expires; 1641e22bee78STejun Heo 164263d95a91STejun Heo worker = list_entry(pool->idle_list.prev, struct worker, entry); 1643e22bee78STejun Heo expires = worker->last_active + IDLE_WORKER_TIMEOUT; 1644e22bee78STejun Heo 1645e22bee78STejun Heo if (time_before(jiffies, expires)) { 164663d95a91STejun Heo mod_timer(&pool->idle_timer, expires); 1647e22bee78STejun Heo break; 1648e22bee78STejun Heo } 1649e22bee78STejun Heo 1650e22bee78STejun Heo destroy_worker(worker); 1651e22bee78STejun Heo ret = true; 1652e22bee78STejun Heo } 1653e22bee78STejun Heo 1654e22bee78STejun Heo return ret; 1655e22bee78STejun Heo } 1656e22bee78STejun Heo 1657e22bee78STejun Heo /** 1658e22bee78STejun Heo * manage_workers - manage worker pool 1659e22bee78STejun Heo * @worker: self 1660e22bee78STejun Heo * 1661e22bee78STejun Heo * Assume the manager role and manage gcwq worker pool @worker belongs 1662e22bee78STejun Heo * to. At any given time, there can be only zero or one manager per 1663e22bee78STejun Heo * gcwq. The exclusion is handled automatically by this function. 1664e22bee78STejun Heo * 1665e22bee78STejun Heo * The caller can safely start processing works on false return. On 1666e22bee78STejun Heo * true return, it's guaranteed that need_to_create_worker() is false 1667e22bee78STejun Heo * and may_start_working() is true. 1668e22bee78STejun Heo * 1669e22bee78STejun Heo * CONTEXT: 1670e22bee78STejun Heo * spin_lock_irq(gcwq->lock) which may be released and regrabbed 1671e22bee78STejun Heo * multiple times. Does GFP_KERNEL allocations. 1672e22bee78STejun Heo * 1673e22bee78STejun Heo * RETURNS: 1674e22bee78STejun Heo * false if no action was taken and gcwq->lock stayed locked, true if 1675e22bee78STejun Heo * some action was taken. 1676e22bee78STejun Heo */ 1677e22bee78STejun Heo static bool manage_workers(struct worker *worker) 1678e22bee78STejun Heo { 167963d95a91STejun Heo struct worker_pool *pool = worker->pool; 168063d95a91STejun Heo struct global_cwq *gcwq = pool->gcwq; 1681e22bee78STejun Heo bool ret = false; 1682e22bee78STejun Heo 1683e22bee78STejun Heo if (gcwq->flags & GCWQ_MANAGING_WORKERS) 1684e22bee78STejun Heo return ret; 1685e22bee78STejun Heo 1686e22bee78STejun Heo gcwq->flags &= ~GCWQ_MANAGE_WORKERS; 1687e22bee78STejun Heo gcwq->flags |= GCWQ_MANAGING_WORKERS; 1688e22bee78STejun Heo 1689e22bee78STejun Heo /* 1690e22bee78STejun Heo * Destroy and then create so that may_start_working() is true 1691e22bee78STejun Heo * on return. 1692e22bee78STejun Heo */ 169363d95a91STejun Heo ret |= maybe_destroy_workers(pool); 169463d95a91STejun Heo ret |= maybe_create_worker(pool); 1695e22bee78STejun Heo 1696e22bee78STejun Heo gcwq->flags &= ~GCWQ_MANAGING_WORKERS; 1697e22bee78STejun Heo 1698e22bee78STejun Heo /* 1699e22bee78STejun Heo * The trustee might be waiting to take over the manager 1700e22bee78STejun Heo * position, tell it we're done. 1701e22bee78STejun Heo */ 1702e22bee78STejun Heo if (unlikely(gcwq->trustee)) 1703e22bee78STejun Heo wake_up_all(&gcwq->trustee_wait); 1704e22bee78STejun Heo 1705e22bee78STejun Heo return ret; 1706e22bee78STejun Heo } 1707e22bee78STejun Heo 1708a62428c0STejun Heo /** 1709affee4b2STejun Heo * move_linked_works - move linked works to a list 1710affee4b2STejun Heo * @work: start of series of works to be scheduled 1711affee4b2STejun Heo * @head: target list to append @work to 1712affee4b2STejun Heo * @nextp: out paramter for nested worklist walking 1713affee4b2STejun Heo * 1714affee4b2STejun Heo * Schedule linked works starting from @work to @head. Work series to 1715affee4b2STejun Heo * be scheduled starts at @work and includes any consecutive work with 1716affee4b2STejun Heo * WORK_STRUCT_LINKED set in its predecessor. 1717affee4b2STejun Heo * 1718affee4b2STejun Heo * If @nextp is not NULL, it's updated to point to the next work of 1719affee4b2STejun Heo * the last scheduled work. This allows move_linked_works() to be 1720affee4b2STejun Heo * nested inside outer list_for_each_entry_safe(). 1721affee4b2STejun Heo * 1722affee4b2STejun Heo * CONTEXT: 17238b03ae3cSTejun Heo * spin_lock_irq(gcwq->lock). 1724affee4b2STejun Heo */ 1725affee4b2STejun Heo static void move_linked_works(struct work_struct *work, struct list_head *head, 1726affee4b2STejun Heo struct work_struct **nextp) 1727affee4b2STejun Heo { 1728affee4b2STejun Heo struct work_struct *n; 1729affee4b2STejun Heo 1730affee4b2STejun Heo /* 1731affee4b2STejun Heo * Linked worklist will always end before the end of the list, 1732affee4b2STejun Heo * use NULL for list head. 1733affee4b2STejun Heo */ 1734affee4b2STejun Heo list_for_each_entry_safe_from(work, n, NULL, entry) { 1735affee4b2STejun Heo list_move_tail(&work->entry, head); 1736affee4b2STejun Heo if (!(*work_data_bits(work) & WORK_STRUCT_LINKED)) 1737affee4b2STejun Heo break; 1738affee4b2STejun Heo } 1739affee4b2STejun Heo 1740affee4b2STejun Heo /* 1741affee4b2STejun Heo * If we're already inside safe list traversal and have moved 1742affee4b2STejun Heo * multiple works to the scheduled queue, the next position 1743affee4b2STejun Heo * needs to be updated. 1744affee4b2STejun Heo */ 1745affee4b2STejun Heo if (nextp) 1746affee4b2STejun Heo *nextp = n; 1747affee4b2STejun Heo } 1748affee4b2STejun Heo 17491e19ffc6STejun Heo static void cwq_activate_first_delayed(struct cpu_workqueue_struct *cwq) 17501e19ffc6STejun Heo { 17511e19ffc6STejun Heo struct work_struct *work = list_first_entry(&cwq->delayed_works, 17521da177e4SLinus Torvalds struct work_struct, entry); 175363d95a91STejun Heo struct list_head *pos = pool_determine_ins_pos(cwq->pool, cwq); 17541e19ffc6STejun Heo 1755cdadf009STejun Heo trace_workqueue_activate_work(work); 1756649027d7STejun Heo move_linked_works(work, pos, NULL); 17578a2e8e5dSTejun Heo __clear_bit(WORK_STRUCT_DELAYED_BIT, work_data_bits(work)); 17581e19ffc6STejun Heo cwq->nr_active++; 17591e19ffc6STejun Heo } 17601e19ffc6STejun Heo 1761affee4b2STejun Heo /** 176273f53c4aSTejun Heo * cwq_dec_nr_in_flight - decrement cwq's nr_in_flight 176373f53c4aSTejun Heo * @cwq: cwq of interest 176473f53c4aSTejun Heo * @color: color of work which left the queue 17658a2e8e5dSTejun Heo * @delayed: for a delayed work 176673f53c4aSTejun Heo * 176773f53c4aSTejun Heo * A work either has completed or is removed from pending queue, 176873f53c4aSTejun Heo * decrement nr_in_flight of its cwq and handle workqueue flushing. 176973f53c4aSTejun Heo * 177073f53c4aSTejun Heo * CONTEXT: 17718b03ae3cSTejun Heo * spin_lock_irq(gcwq->lock). 177273f53c4aSTejun Heo */ 17738a2e8e5dSTejun Heo static void cwq_dec_nr_in_flight(struct cpu_workqueue_struct *cwq, int color, 17748a2e8e5dSTejun Heo bool delayed) 177573f53c4aSTejun Heo { 177673f53c4aSTejun Heo /* ignore uncolored works */ 177773f53c4aSTejun Heo if (color == WORK_NO_COLOR) 177873f53c4aSTejun Heo return; 177973f53c4aSTejun Heo 178073f53c4aSTejun Heo cwq->nr_in_flight[color]--; 17811e19ffc6STejun Heo 17828a2e8e5dSTejun Heo if (!delayed) { 17838a2e8e5dSTejun Heo cwq->nr_active--; 1784502ca9d8STejun Heo if (!list_empty(&cwq->delayed_works)) { 17851e19ffc6STejun Heo /* one down, submit a delayed one */ 1786502ca9d8STejun Heo if (cwq->nr_active < cwq->max_active) 17871e19ffc6STejun Heo cwq_activate_first_delayed(cwq); 1788502ca9d8STejun Heo } 17898a2e8e5dSTejun Heo } 179073f53c4aSTejun Heo 179173f53c4aSTejun Heo /* is flush in progress and are we at the flushing tip? */ 179273f53c4aSTejun Heo if (likely(cwq->flush_color != color)) 179373f53c4aSTejun Heo return; 179473f53c4aSTejun Heo 179573f53c4aSTejun Heo /* are there still in-flight works? */ 179673f53c4aSTejun Heo if (cwq->nr_in_flight[color]) 179773f53c4aSTejun Heo return; 179873f53c4aSTejun Heo 179973f53c4aSTejun Heo /* this cwq is done, clear flush_color */ 180073f53c4aSTejun Heo cwq->flush_color = -1; 180173f53c4aSTejun Heo 180273f53c4aSTejun Heo /* 180373f53c4aSTejun Heo * If this was the last cwq, wake up the first flusher. It 180473f53c4aSTejun Heo * will handle the rest. 180573f53c4aSTejun Heo */ 180673f53c4aSTejun Heo if (atomic_dec_and_test(&cwq->wq->nr_cwqs_to_flush)) 180773f53c4aSTejun Heo complete(&cwq->wq->first_flusher->done); 180873f53c4aSTejun Heo } 180973f53c4aSTejun Heo 181073f53c4aSTejun Heo /** 1811a62428c0STejun Heo * process_one_work - process single work 1812c34056a3STejun Heo * @worker: self 1813a62428c0STejun Heo * @work: work to process 1814a62428c0STejun Heo * 1815a62428c0STejun Heo * Process @work. This function contains all the logics necessary to 1816a62428c0STejun Heo * process a single work including synchronization against and 1817a62428c0STejun Heo * interaction with other workers on the same cpu, queueing and 1818a62428c0STejun Heo * flushing. As long as context requirement is met, any worker can 1819a62428c0STejun Heo * call this function to process a work. 1820a62428c0STejun Heo * 1821a62428c0STejun Heo * CONTEXT: 18228b03ae3cSTejun Heo * spin_lock_irq(gcwq->lock) which is released and regrabbed. 1823a62428c0STejun Heo */ 1824c34056a3STejun Heo static void process_one_work(struct worker *worker, struct work_struct *work) 182506bd6ebfSNamhyung Kim __releases(&gcwq->lock) 182606bd6ebfSNamhyung Kim __acquires(&gcwq->lock) 18271da177e4SLinus Torvalds { 18287e11629dSTejun Heo struct cpu_workqueue_struct *cwq = get_work_cwq(work); 1829bd7bdd43STejun Heo struct worker_pool *pool = worker->pool; 1830bd7bdd43STejun Heo struct global_cwq *gcwq = pool->gcwq; 1831c8e55f36STejun Heo struct hlist_head *bwh = busy_worker_head(gcwq, work); 1832fb0e7bebSTejun Heo bool cpu_intensive = cwq->wq->flags & WQ_CPU_INTENSIVE; 18336bb49e59SDavid Howells work_func_t f = work->func; 183473f53c4aSTejun Heo int work_color; 18357e11629dSTejun Heo struct worker *collision; 18364e6045f1SJohannes Berg #ifdef CONFIG_LOCKDEP 18374e6045f1SJohannes Berg /* 1838a62428c0STejun Heo * It is permissible to free the struct work_struct from 1839a62428c0STejun Heo * inside the function that is called from it, this we need to 1840a62428c0STejun Heo * take into account for lockdep too. To avoid bogus "held 1841a62428c0STejun Heo * lock freed" warnings as well as problems when looking into 1842a62428c0STejun Heo * work->lockdep_map, make a copy and use that here. 18434e6045f1SJohannes Berg */ 18444d82a1deSPeter Zijlstra struct lockdep_map lockdep_map; 18454d82a1deSPeter Zijlstra 18464d82a1deSPeter Zijlstra lockdep_copy_map(&lockdep_map, &work->lockdep_map); 18474e6045f1SJohannes Berg #endif 18487e11629dSTejun Heo /* 18497e11629dSTejun Heo * A single work shouldn't be executed concurrently by 18507e11629dSTejun Heo * multiple workers on a single cpu. Check whether anyone is 18517e11629dSTejun Heo * already processing the work. If so, defer the work to the 18527e11629dSTejun Heo * currently executing one. 18537e11629dSTejun Heo */ 18547e11629dSTejun Heo collision = __find_worker_executing_work(gcwq, bwh, work); 18557e11629dSTejun Heo if (unlikely(collision)) { 18567e11629dSTejun Heo move_linked_works(work, &collision->scheduled, NULL); 18577e11629dSTejun Heo return; 18587e11629dSTejun Heo } 18591da177e4SLinus Torvalds 1860a62428c0STejun Heo /* claim and process */ 18611da177e4SLinus Torvalds debug_work_deactivate(work); 1862c8e55f36STejun Heo hlist_add_head(&worker->hentry, bwh); 1863c34056a3STejun Heo worker->current_work = work; 18648cca0eeaSTejun Heo worker->current_cwq = cwq; 186573f53c4aSTejun Heo work_color = get_work_color(work); 18667a22ad75STejun Heo 18677a22ad75STejun Heo /* record the current cpu number in the work data and dequeue */ 18687a22ad75STejun Heo set_work_cpu(work, gcwq->cpu); 1869a62428c0STejun Heo list_del_init(&work->entry); 1870a62428c0STejun Heo 1871649027d7STejun Heo /* 1872649027d7STejun Heo * If HIGHPRI_PENDING, check the next work, and, if HIGHPRI, 1873649027d7STejun Heo * wake up another worker; otherwise, clear HIGHPRI_PENDING. 1874649027d7STejun Heo */ 1875649027d7STejun Heo if (unlikely(gcwq->flags & GCWQ_HIGHPRI_PENDING)) { 1876bd7bdd43STejun Heo struct work_struct *nwork = list_first_entry(&pool->worklist, 1877649027d7STejun Heo struct work_struct, entry); 1878649027d7STejun Heo 1879bd7bdd43STejun Heo if (!list_empty(&pool->worklist) && 1880649027d7STejun Heo get_work_cwq(nwork)->wq->flags & WQ_HIGHPRI) 188163d95a91STejun Heo wake_up_worker(pool); 1882649027d7STejun Heo else 1883649027d7STejun Heo gcwq->flags &= ~GCWQ_HIGHPRI_PENDING; 1884649027d7STejun Heo } 1885649027d7STejun Heo 1886fb0e7bebSTejun Heo /* 1887fb0e7bebSTejun Heo * CPU intensive works don't participate in concurrency 1888fb0e7bebSTejun Heo * management. They're the scheduler's responsibility. 1889fb0e7bebSTejun Heo */ 1890fb0e7bebSTejun Heo if (unlikely(cpu_intensive)) 1891fb0e7bebSTejun Heo worker_set_flags(worker, WORKER_CPU_INTENSIVE, true); 1892fb0e7bebSTejun Heo 1893974271c4STejun Heo /* 1894974271c4STejun Heo * Unbound gcwq isn't concurrency managed and work items should be 1895974271c4STejun Heo * executed ASAP. Wake up another worker if necessary. 1896974271c4STejun Heo */ 189763d95a91STejun Heo if ((worker->flags & WORKER_UNBOUND) && need_more_worker(pool)) 189863d95a91STejun Heo wake_up_worker(pool); 1899974271c4STejun Heo 19008b03ae3cSTejun Heo spin_unlock_irq(&gcwq->lock); 19011da177e4SLinus Torvalds 190223b2e599SOleg Nesterov work_clear_pending(work); 1903e159489bSTejun Heo lock_map_acquire_read(&cwq->wq->lockdep_map); 19043295f0efSIngo Molnar lock_map_acquire(&lockdep_map); 1905e36c886aSArjan van de Ven trace_workqueue_execute_start(work); 190665f27f38SDavid Howells f(work); 1907e36c886aSArjan van de Ven /* 1908e36c886aSArjan van de Ven * While we must be careful to not use "work" after this, the trace 1909e36c886aSArjan van de Ven * point will only record its address. 1910e36c886aSArjan van de Ven */ 1911e36c886aSArjan van de Ven trace_workqueue_execute_end(work); 19123295f0efSIngo Molnar lock_map_release(&lockdep_map); 19133295f0efSIngo Molnar lock_map_release(&cwq->wq->lockdep_map); 19141da177e4SLinus Torvalds 1915d5abe669SPeter Zijlstra if (unlikely(in_atomic() || lockdep_depth(current) > 0)) { 1916d5abe669SPeter Zijlstra printk(KERN_ERR "BUG: workqueue leaked lock or atomic: " 1917d5abe669SPeter Zijlstra "%s/0x%08x/%d\n", 1918a62428c0STejun Heo current->comm, preempt_count(), task_pid_nr(current)); 1919d5abe669SPeter Zijlstra printk(KERN_ERR " last function: "); 1920d5abe669SPeter Zijlstra print_symbol("%s\n", (unsigned long)f); 1921d5abe669SPeter Zijlstra debug_show_held_locks(current); 1922d5abe669SPeter Zijlstra dump_stack(); 1923d5abe669SPeter Zijlstra } 1924d5abe669SPeter Zijlstra 19258b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 1926a62428c0STejun Heo 1927fb0e7bebSTejun Heo /* clear cpu intensive status */ 1928fb0e7bebSTejun Heo if (unlikely(cpu_intensive)) 1929fb0e7bebSTejun Heo worker_clr_flags(worker, WORKER_CPU_INTENSIVE); 1930fb0e7bebSTejun Heo 1931a62428c0STejun Heo /* we're done with it, release */ 1932c8e55f36STejun Heo hlist_del_init(&worker->hentry); 1933c34056a3STejun Heo worker->current_work = NULL; 19348cca0eeaSTejun Heo worker->current_cwq = NULL; 19358a2e8e5dSTejun Heo cwq_dec_nr_in_flight(cwq, work_color, false); 19361da177e4SLinus Torvalds } 19371da177e4SLinus Torvalds 1938affee4b2STejun Heo /** 1939affee4b2STejun Heo * process_scheduled_works - process scheduled works 1940affee4b2STejun Heo * @worker: self 1941affee4b2STejun Heo * 1942affee4b2STejun Heo * Process all scheduled works. Please note that the scheduled list 1943affee4b2STejun Heo * may change while processing a work, so this function repeatedly 1944affee4b2STejun Heo * fetches a work from the top and executes it. 1945affee4b2STejun Heo * 1946affee4b2STejun Heo * CONTEXT: 19478b03ae3cSTejun Heo * spin_lock_irq(gcwq->lock) which may be released and regrabbed 1948affee4b2STejun Heo * multiple times. 1949affee4b2STejun Heo */ 1950affee4b2STejun Heo static void process_scheduled_works(struct worker *worker) 19511da177e4SLinus Torvalds { 1952affee4b2STejun Heo while (!list_empty(&worker->scheduled)) { 1953affee4b2STejun Heo struct work_struct *work = list_first_entry(&worker->scheduled, 1954a62428c0STejun Heo struct work_struct, entry); 1955c34056a3STejun Heo process_one_work(worker, work); 1956a62428c0STejun Heo } 19571da177e4SLinus Torvalds } 19581da177e4SLinus Torvalds 19594690c4abSTejun Heo /** 19604690c4abSTejun Heo * worker_thread - the worker thread function 1961c34056a3STejun Heo * @__worker: self 19624690c4abSTejun Heo * 1963e22bee78STejun Heo * The gcwq worker thread function. There's a single dynamic pool of 1964e22bee78STejun Heo * these per each cpu. These workers process all works regardless of 1965e22bee78STejun Heo * their specific target workqueue. The only exception is works which 1966e22bee78STejun Heo * belong to workqueues with a rescuer which will be explained in 1967e22bee78STejun Heo * rescuer_thread(). 19684690c4abSTejun Heo */ 1969c34056a3STejun Heo static int worker_thread(void *__worker) 19701da177e4SLinus Torvalds { 1971c34056a3STejun Heo struct worker *worker = __worker; 1972bd7bdd43STejun Heo struct worker_pool *pool = worker->pool; 1973bd7bdd43STejun Heo struct global_cwq *gcwq = pool->gcwq; 19741da177e4SLinus Torvalds 1975e22bee78STejun Heo /* tell the scheduler that this is a workqueue worker */ 1976e22bee78STejun Heo worker->task->flags |= PF_WQ_WORKER; 1977c8e55f36STejun Heo woke_up: 19788b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 1979affee4b2STejun Heo 1980c8e55f36STejun Heo /* DIE can be set only while we're idle, checking here is enough */ 1981c8e55f36STejun Heo if (worker->flags & WORKER_DIE) { 1982c8e55f36STejun Heo spin_unlock_irq(&gcwq->lock); 1983e22bee78STejun Heo worker->task->flags &= ~PF_WQ_WORKER; 1984c8e55f36STejun Heo return 0; 1985c8e55f36STejun Heo } 1986c8e55f36STejun Heo 1987c8e55f36STejun Heo worker_leave_idle(worker); 1988db7bccf4STejun Heo recheck: 1989e22bee78STejun Heo /* no more worker necessary? */ 199063d95a91STejun Heo if (!need_more_worker(pool)) 1991e22bee78STejun Heo goto sleep; 1992e22bee78STejun Heo 1993e22bee78STejun Heo /* do we need to manage? */ 199463d95a91STejun Heo if (unlikely(!may_start_working(pool)) && manage_workers(worker)) 1995e22bee78STejun Heo goto recheck; 1996e22bee78STejun Heo 1997c8e55f36STejun Heo /* 1998c8e55f36STejun Heo * ->scheduled list can only be filled while a worker is 1999c8e55f36STejun Heo * preparing to process a work or actually processing it. 2000c8e55f36STejun Heo * Make sure nobody diddled with it while I was sleeping. 2001c8e55f36STejun Heo */ 2002c8e55f36STejun Heo BUG_ON(!list_empty(&worker->scheduled)); 2003c8e55f36STejun Heo 2004e22bee78STejun Heo /* 2005e22bee78STejun Heo * When control reaches this point, we're guaranteed to have 2006e22bee78STejun Heo * at least one idle worker or that someone else has already 2007e22bee78STejun Heo * assumed the manager role. 2008e22bee78STejun Heo */ 2009e22bee78STejun Heo worker_clr_flags(worker, WORKER_PREP); 2010e22bee78STejun Heo 2011e22bee78STejun Heo do { 2012affee4b2STejun Heo struct work_struct *work = 2013bd7bdd43STejun Heo list_first_entry(&pool->worklist, 2014affee4b2STejun Heo struct work_struct, entry); 2015affee4b2STejun Heo 2016c8e55f36STejun Heo if (likely(!(*work_data_bits(work) & WORK_STRUCT_LINKED))) { 2017affee4b2STejun Heo /* optimization path, not strictly necessary */ 2018affee4b2STejun Heo process_one_work(worker, work); 2019affee4b2STejun Heo if (unlikely(!list_empty(&worker->scheduled))) 2020affee4b2STejun Heo process_scheduled_works(worker); 2021affee4b2STejun Heo } else { 2022c8e55f36STejun Heo move_linked_works(work, &worker->scheduled, NULL); 2023affee4b2STejun Heo process_scheduled_works(worker); 2024affee4b2STejun Heo } 202563d95a91STejun Heo } while (keep_working(pool)); 2026affee4b2STejun Heo 2027e22bee78STejun Heo worker_set_flags(worker, WORKER_PREP, false); 2028d313dd85STejun Heo sleep: 202963d95a91STejun Heo if (unlikely(need_to_manage_workers(pool)) && manage_workers(worker)) 2030e22bee78STejun Heo goto recheck; 2031d313dd85STejun Heo 2032c8e55f36STejun Heo /* 2033e22bee78STejun Heo * gcwq->lock is held and there's no work to process and no 2034e22bee78STejun Heo * need to manage, sleep. Workers are woken up only while 2035e22bee78STejun Heo * holding gcwq->lock or from local cpu, so setting the 2036e22bee78STejun Heo * current state before releasing gcwq->lock is enough to 2037e22bee78STejun Heo * prevent losing any event. 2038c8e55f36STejun Heo */ 2039c8e55f36STejun Heo worker_enter_idle(worker); 2040c8e55f36STejun Heo __set_current_state(TASK_INTERRUPTIBLE); 20418b03ae3cSTejun Heo spin_unlock_irq(&gcwq->lock); 20421da177e4SLinus Torvalds schedule(); 2043c8e55f36STejun Heo goto woke_up; 20441da177e4SLinus Torvalds } 20451da177e4SLinus Torvalds 2046e22bee78STejun Heo /** 2047e22bee78STejun Heo * rescuer_thread - the rescuer thread function 2048e22bee78STejun Heo * @__wq: the associated workqueue 2049e22bee78STejun Heo * 2050e22bee78STejun Heo * Workqueue rescuer thread function. There's one rescuer for each 2051e22bee78STejun Heo * workqueue which has WQ_RESCUER set. 2052e22bee78STejun Heo * 2053e22bee78STejun Heo * Regular work processing on a gcwq may block trying to create a new 2054e22bee78STejun Heo * worker which uses GFP_KERNEL allocation which has slight chance of 2055e22bee78STejun Heo * developing into deadlock if some works currently on the same queue 2056e22bee78STejun Heo * need to be processed to satisfy the GFP_KERNEL allocation. This is 2057e22bee78STejun Heo * the problem rescuer solves. 2058e22bee78STejun Heo * 2059e22bee78STejun Heo * When such condition is possible, the gcwq summons rescuers of all 2060e22bee78STejun Heo * workqueues which have works queued on the gcwq and let them process 2061e22bee78STejun Heo * those works so that forward progress can be guaranteed. 2062e22bee78STejun Heo * 2063e22bee78STejun Heo * This should happen rarely. 2064e22bee78STejun Heo */ 2065e22bee78STejun Heo static int rescuer_thread(void *__wq) 2066e22bee78STejun Heo { 2067e22bee78STejun Heo struct workqueue_struct *wq = __wq; 2068e22bee78STejun Heo struct worker *rescuer = wq->rescuer; 2069e22bee78STejun Heo struct list_head *scheduled = &rescuer->scheduled; 2070f3421797STejun Heo bool is_unbound = wq->flags & WQ_UNBOUND; 2071e22bee78STejun Heo unsigned int cpu; 2072e22bee78STejun Heo 2073e22bee78STejun Heo set_user_nice(current, RESCUER_NICE_LEVEL); 2074e22bee78STejun Heo repeat: 2075e22bee78STejun Heo set_current_state(TASK_INTERRUPTIBLE); 20761da177e4SLinus Torvalds 20771da177e4SLinus Torvalds if (kthread_should_stop()) 2078e22bee78STejun Heo return 0; 20791da177e4SLinus Torvalds 2080f3421797STejun Heo /* 2081f3421797STejun Heo * See whether any cpu is asking for help. Unbounded 2082f3421797STejun Heo * workqueues use cpu 0 in mayday_mask for CPU_UNBOUND. 2083f3421797STejun Heo */ 2084f2e005aaSTejun Heo for_each_mayday_cpu(cpu, wq->mayday_mask) { 2085f3421797STejun Heo unsigned int tcpu = is_unbound ? WORK_CPU_UNBOUND : cpu; 2086f3421797STejun Heo struct cpu_workqueue_struct *cwq = get_cwq(tcpu, wq); 2087bd7bdd43STejun Heo struct worker_pool *pool = cwq->pool; 2088bd7bdd43STejun Heo struct global_cwq *gcwq = pool->gcwq; 2089e22bee78STejun Heo struct work_struct *work, *n; 2090e22bee78STejun Heo 2091e22bee78STejun Heo __set_current_state(TASK_RUNNING); 2092f2e005aaSTejun Heo mayday_clear_cpu(cpu, wq->mayday_mask); 2093e22bee78STejun Heo 2094e22bee78STejun Heo /* migrate to the target cpu if possible */ 2095bd7bdd43STejun Heo rescuer->pool = pool; 2096e22bee78STejun Heo worker_maybe_bind_and_lock(rescuer); 2097e22bee78STejun Heo 2098e22bee78STejun Heo /* 2099e22bee78STejun Heo * Slurp in all works issued via this workqueue and 2100e22bee78STejun Heo * process'em. 2101e22bee78STejun Heo */ 2102e22bee78STejun Heo BUG_ON(!list_empty(&rescuer->scheduled)); 2103bd7bdd43STejun Heo list_for_each_entry_safe(work, n, &pool->worklist, entry) 2104e22bee78STejun Heo if (get_work_cwq(work) == cwq) 2105e22bee78STejun Heo move_linked_works(work, scheduled, &n); 2106e22bee78STejun Heo 2107e22bee78STejun Heo process_scheduled_works(rescuer); 21087576958aSTejun Heo 21097576958aSTejun Heo /* 21107576958aSTejun Heo * Leave this gcwq. If keep_working() is %true, notify a 21117576958aSTejun Heo * regular worker; otherwise, we end up with 0 concurrency 21127576958aSTejun Heo * and stalling the execution. 21137576958aSTejun Heo */ 211463d95a91STejun Heo if (keep_working(pool)) 211563d95a91STejun Heo wake_up_worker(pool); 21167576958aSTejun Heo 2117e22bee78STejun Heo spin_unlock_irq(&gcwq->lock); 21181da177e4SLinus Torvalds } 21191da177e4SLinus Torvalds 2120e22bee78STejun Heo schedule(); 2121e22bee78STejun Heo goto repeat; 21221da177e4SLinus Torvalds } 21231da177e4SLinus Torvalds 2124fc2e4d70SOleg Nesterov struct wq_barrier { 2125fc2e4d70SOleg Nesterov struct work_struct work; 2126fc2e4d70SOleg Nesterov struct completion done; 2127fc2e4d70SOleg Nesterov }; 2128fc2e4d70SOleg Nesterov 2129fc2e4d70SOleg Nesterov static void wq_barrier_func(struct work_struct *work) 2130fc2e4d70SOleg Nesterov { 2131fc2e4d70SOleg Nesterov struct wq_barrier *barr = container_of(work, struct wq_barrier, work); 2132fc2e4d70SOleg Nesterov complete(&barr->done); 2133fc2e4d70SOleg Nesterov } 2134fc2e4d70SOleg Nesterov 21354690c4abSTejun Heo /** 21364690c4abSTejun Heo * insert_wq_barrier - insert a barrier work 21374690c4abSTejun Heo * @cwq: cwq to insert barrier into 21384690c4abSTejun Heo * @barr: wq_barrier to insert 2139affee4b2STejun Heo * @target: target work to attach @barr to 2140affee4b2STejun Heo * @worker: worker currently executing @target, NULL if @target is not executing 21414690c4abSTejun Heo * 2142affee4b2STejun Heo * @barr is linked to @target such that @barr is completed only after 2143affee4b2STejun Heo * @target finishes execution. Please note that the ordering 2144affee4b2STejun Heo * guarantee is observed only with respect to @target and on the local 2145affee4b2STejun Heo * cpu. 2146affee4b2STejun Heo * 2147affee4b2STejun Heo * Currently, a queued barrier can't be canceled. This is because 2148affee4b2STejun Heo * try_to_grab_pending() can't determine whether the work to be 2149affee4b2STejun Heo * grabbed is at the head of the queue and thus can't clear LINKED 2150affee4b2STejun Heo * flag of the previous work while there must be a valid next work 2151affee4b2STejun Heo * after a work with LINKED flag set. 2152affee4b2STejun Heo * 2153affee4b2STejun Heo * Note that when @worker is non-NULL, @target may be modified 2154affee4b2STejun Heo * underneath us, so we can't reliably determine cwq from @target. 21554690c4abSTejun Heo * 21564690c4abSTejun Heo * CONTEXT: 21578b03ae3cSTejun Heo * spin_lock_irq(gcwq->lock). 21584690c4abSTejun Heo */ 215983c22520SOleg Nesterov static void insert_wq_barrier(struct cpu_workqueue_struct *cwq, 2160affee4b2STejun Heo struct wq_barrier *barr, 2161affee4b2STejun Heo struct work_struct *target, struct worker *worker) 2162fc2e4d70SOleg Nesterov { 2163affee4b2STejun Heo struct list_head *head; 2164affee4b2STejun Heo unsigned int linked = 0; 2165affee4b2STejun Heo 2166dc186ad7SThomas Gleixner /* 21678b03ae3cSTejun Heo * debugobject calls are safe here even with gcwq->lock locked 2168dc186ad7SThomas Gleixner * as we know for sure that this will not trigger any of the 2169dc186ad7SThomas Gleixner * checks and call back into the fixup functions where we 2170dc186ad7SThomas Gleixner * might deadlock. 2171dc186ad7SThomas Gleixner */ 2172ca1cab37SAndrew Morton INIT_WORK_ONSTACK(&barr->work, wq_barrier_func); 217322df02bbSTejun Heo __set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&barr->work)); 2174fc2e4d70SOleg Nesterov init_completion(&barr->done); 217583c22520SOleg Nesterov 2176affee4b2STejun Heo /* 2177affee4b2STejun Heo * If @target is currently being executed, schedule the 2178affee4b2STejun Heo * barrier to the worker; otherwise, put it after @target. 2179affee4b2STejun Heo */ 2180affee4b2STejun Heo if (worker) 2181affee4b2STejun Heo head = worker->scheduled.next; 2182affee4b2STejun Heo else { 2183affee4b2STejun Heo unsigned long *bits = work_data_bits(target); 2184affee4b2STejun Heo 2185affee4b2STejun Heo head = target->entry.next; 2186affee4b2STejun Heo /* there can already be other linked works, inherit and set */ 2187affee4b2STejun Heo linked = *bits & WORK_STRUCT_LINKED; 2188affee4b2STejun Heo __set_bit(WORK_STRUCT_LINKED_BIT, bits); 2189affee4b2STejun Heo } 2190affee4b2STejun Heo 2191dc186ad7SThomas Gleixner debug_work_activate(&barr->work); 2192affee4b2STejun Heo insert_work(cwq, &barr->work, head, 2193affee4b2STejun Heo work_color_to_flags(WORK_NO_COLOR) | linked); 2194fc2e4d70SOleg Nesterov } 2195fc2e4d70SOleg Nesterov 219673f53c4aSTejun Heo /** 219773f53c4aSTejun Heo * flush_workqueue_prep_cwqs - prepare cwqs for workqueue flushing 219873f53c4aSTejun Heo * @wq: workqueue being flushed 219973f53c4aSTejun Heo * @flush_color: new flush color, < 0 for no-op 220073f53c4aSTejun Heo * @work_color: new work color, < 0 for no-op 220173f53c4aSTejun Heo * 220273f53c4aSTejun Heo * Prepare cwqs for workqueue flushing. 220373f53c4aSTejun Heo * 220473f53c4aSTejun Heo * If @flush_color is non-negative, flush_color on all cwqs should be 220573f53c4aSTejun Heo * -1. If no cwq has in-flight commands at the specified color, all 220673f53c4aSTejun Heo * cwq->flush_color's stay at -1 and %false is returned. If any cwq 220773f53c4aSTejun Heo * has in flight commands, its cwq->flush_color is set to 220873f53c4aSTejun Heo * @flush_color, @wq->nr_cwqs_to_flush is updated accordingly, cwq 220973f53c4aSTejun Heo * wakeup logic is armed and %true is returned. 221073f53c4aSTejun Heo * 221173f53c4aSTejun Heo * The caller should have initialized @wq->first_flusher prior to 221273f53c4aSTejun Heo * calling this function with non-negative @flush_color. If 221373f53c4aSTejun Heo * @flush_color is negative, no flush color update is done and %false 221473f53c4aSTejun Heo * is returned. 221573f53c4aSTejun Heo * 221673f53c4aSTejun Heo * If @work_color is non-negative, all cwqs should have the same 221773f53c4aSTejun Heo * work_color which is previous to @work_color and all will be 221873f53c4aSTejun Heo * advanced to @work_color. 221973f53c4aSTejun Heo * 222073f53c4aSTejun Heo * CONTEXT: 222173f53c4aSTejun Heo * mutex_lock(wq->flush_mutex). 222273f53c4aSTejun Heo * 222373f53c4aSTejun Heo * RETURNS: 222473f53c4aSTejun Heo * %true if @flush_color >= 0 and there's something to flush. %false 222573f53c4aSTejun Heo * otherwise. 222673f53c4aSTejun Heo */ 222773f53c4aSTejun Heo static bool flush_workqueue_prep_cwqs(struct workqueue_struct *wq, 222873f53c4aSTejun Heo int flush_color, int work_color) 22291da177e4SLinus Torvalds { 223073f53c4aSTejun Heo bool wait = false; 223173f53c4aSTejun Heo unsigned int cpu; 22321da177e4SLinus Torvalds 223373f53c4aSTejun Heo if (flush_color >= 0) { 223473f53c4aSTejun Heo BUG_ON(atomic_read(&wq->nr_cwqs_to_flush)); 223573f53c4aSTejun Heo atomic_set(&wq->nr_cwqs_to_flush, 1); 2236dc186ad7SThomas Gleixner } 223714441960SOleg Nesterov 2238f3421797STejun Heo for_each_cwq_cpu(cpu, wq) { 223973f53c4aSTejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 2240bd7bdd43STejun Heo struct global_cwq *gcwq = cwq->pool->gcwq; 22411da177e4SLinus Torvalds 22428b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 224373f53c4aSTejun Heo 224473f53c4aSTejun Heo if (flush_color >= 0) { 224573f53c4aSTejun Heo BUG_ON(cwq->flush_color != -1); 224673f53c4aSTejun Heo 224773f53c4aSTejun Heo if (cwq->nr_in_flight[flush_color]) { 224873f53c4aSTejun Heo cwq->flush_color = flush_color; 224973f53c4aSTejun Heo atomic_inc(&wq->nr_cwqs_to_flush); 225073f53c4aSTejun Heo wait = true; 22511da177e4SLinus Torvalds } 225273f53c4aSTejun Heo } 225373f53c4aSTejun Heo 225473f53c4aSTejun Heo if (work_color >= 0) { 225573f53c4aSTejun Heo BUG_ON(work_color != work_next_color(cwq->work_color)); 225673f53c4aSTejun Heo cwq->work_color = work_color; 225773f53c4aSTejun Heo } 225873f53c4aSTejun Heo 22598b03ae3cSTejun Heo spin_unlock_irq(&gcwq->lock); 22601da177e4SLinus Torvalds } 22611da177e4SLinus Torvalds 226273f53c4aSTejun Heo if (flush_color >= 0 && atomic_dec_and_test(&wq->nr_cwqs_to_flush)) 226373f53c4aSTejun Heo complete(&wq->first_flusher->done); 226473f53c4aSTejun Heo 226573f53c4aSTejun Heo return wait; 226683c22520SOleg Nesterov } 22671da177e4SLinus Torvalds 22680fcb78c2SRolf Eike Beer /** 22691da177e4SLinus Torvalds * flush_workqueue - ensure that any scheduled work has run to completion. 22700fcb78c2SRolf Eike Beer * @wq: workqueue to flush 22711da177e4SLinus Torvalds * 22721da177e4SLinus Torvalds * Forces execution of the workqueue and blocks until its completion. 22731da177e4SLinus Torvalds * This is typically used in driver shutdown handlers. 22741da177e4SLinus Torvalds * 2275fc2e4d70SOleg Nesterov * We sleep until all works which were queued on entry have been handled, 2276fc2e4d70SOleg Nesterov * but we are not livelocked by new incoming ones. 22771da177e4SLinus Torvalds */ 22787ad5b3a5SHarvey Harrison void flush_workqueue(struct workqueue_struct *wq) 22791da177e4SLinus Torvalds { 228073f53c4aSTejun Heo struct wq_flusher this_flusher = { 228173f53c4aSTejun Heo .list = LIST_HEAD_INIT(this_flusher.list), 228273f53c4aSTejun Heo .flush_color = -1, 228373f53c4aSTejun Heo .done = COMPLETION_INITIALIZER_ONSTACK(this_flusher.done), 228473f53c4aSTejun Heo }; 228573f53c4aSTejun Heo int next_color; 2286b1f4ec17SOleg Nesterov 22873295f0efSIngo Molnar lock_map_acquire(&wq->lockdep_map); 22883295f0efSIngo Molnar lock_map_release(&wq->lockdep_map); 228973f53c4aSTejun Heo 229073f53c4aSTejun Heo mutex_lock(&wq->flush_mutex); 229173f53c4aSTejun Heo 229273f53c4aSTejun Heo /* 229373f53c4aSTejun Heo * Start-to-wait phase 229473f53c4aSTejun Heo */ 229573f53c4aSTejun Heo next_color = work_next_color(wq->work_color); 229673f53c4aSTejun Heo 229773f53c4aSTejun Heo if (next_color != wq->flush_color) { 229873f53c4aSTejun Heo /* 229973f53c4aSTejun Heo * Color space is not full. The current work_color 230073f53c4aSTejun Heo * becomes our flush_color and work_color is advanced 230173f53c4aSTejun Heo * by one. 230273f53c4aSTejun Heo */ 230373f53c4aSTejun Heo BUG_ON(!list_empty(&wq->flusher_overflow)); 230473f53c4aSTejun Heo this_flusher.flush_color = wq->work_color; 230573f53c4aSTejun Heo wq->work_color = next_color; 230673f53c4aSTejun Heo 230773f53c4aSTejun Heo if (!wq->first_flusher) { 230873f53c4aSTejun Heo /* no flush in progress, become the first flusher */ 230973f53c4aSTejun Heo BUG_ON(wq->flush_color != this_flusher.flush_color); 231073f53c4aSTejun Heo 231173f53c4aSTejun Heo wq->first_flusher = &this_flusher; 231273f53c4aSTejun Heo 231373f53c4aSTejun Heo if (!flush_workqueue_prep_cwqs(wq, wq->flush_color, 231473f53c4aSTejun Heo wq->work_color)) { 231573f53c4aSTejun Heo /* nothing to flush, done */ 231673f53c4aSTejun Heo wq->flush_color = next_color; 231773f53c4aSTejun Heo wq->first_flusher = NULL; 231873f53c4aSTejun Heo goto out_unlock; 231973f53c4aSTejun Heo } 232073f53c4aSTejun Heo } else { 232173f53c4aSTejun Heo /* wait in queue */ 232273f53c4aSTejun Heo BUG_ON(wq->flush_color == this_flusher.flush_color); 232373f53c4aSTejun Heo list_add_tail(&this_flusher.list, &wq->flusher_queue); 232473f53c4aSTejun Heo flush_workqueue_prep_cwqs(wq, -1, wq->work_color); 232573f53c4aSTejun Heo } 232673f53c4aSTejun Heo } else { 232773f53c4aSTejun Heo /* 232873f53c4aSTejun Heo * Oops, color space is full, wait on overflow queue. 232973f53c4aSTejun Heo * The next flush completion will assign us 233073f53c4aSTejun Heo * flush_color and transfer to flusher_queue. 233173f53c4aSTejun Heo */ 233273f53c4aSTejun Heo list_add_tail(&this_flusher.list, &wq->flusher_overflow); 233373f53c4aSTejun Heo } 233473f53c4aSTejun Heo 233573f53c4aSTejun Heo mutex_unlock(&wq->flush_mutex); 233673f53c4aSTejun Heo 233773f53c4aSTejun Heo wait_for_completion(&this_flusher.done); 233873f53c4aSTejun Heo 233973f53c4aSTejun Heo /* 234073f53c4aSTejun Heo * Wake-up-and-cascade phase 234173f53c4aSTejun Heo * 234273f53c4aSTejun Heo * First flushers are responsible for cascading flushes and 234373f53c4aSTejun Heo * handling overflow. Non-first flushers can simply return. 234473f53c4aSTejun Heo */ 234573f53c4aSTejun Heo if (wq->first_flusher != &this_flusher) 234673f53c4aSTejun Heo return; 234773f53c4aSTejun Heo 234873f53c4aSTejun Heo mutex_lock(&wq->flush_mutex); 234973f53c4aSTejun Heo 23504ce48b37STejun Heo /* we might have raced, check again with mutex held */ 23514ce48b37STejun Heo if (wq->first_flusher != &this_flusher) 23524ce48b37STejun Heo goto out_unlock; 23534ce48b37STejun Heo 235473f53c4aSTejun Heo wq->first_flusher = NULL; 235573f53c4aSTejun Heo 235673f53c4aSTejun Heo BUG_ON(!list_empty(&this_flusher.list)); 235773f53c4aSTejun Heo BUG_ON(wq->flush_color != this_flusher.flush_color); 235873f53c4aSTejun Heo 235973f53c4aSTejun Heo while (true) { 236073f53c4aSTejun Heo struct wq_flusher *next, *tmp; 236173f53c4aSTejun Heo 236273f53c4aSTejun Heo /* complete all the flushers sharing the current flush color */ 236373f53c4aSTejun Heo list_for_each_entry_safe(next, tmp, &wq->flusher_queue, list) { 236473f53c4aSTejun Heo if (next->flush_color != wq->flush_color) 236573f53c4aSTejun Heo break; 236673f53c4aSTejun Heo list_del_init(&next->list); 236773f53c4aSTejun Heo complete(&next->done); 236873f53c4aSTejun Heo } 236973f53c4aSTejun Heo 237073f53c4aSTejun Heo BUG_ON(!list_empty(&wq->flusher_overflow) && 237173f53c4aSTejun Heo wq->flush_color != work_next_color(wq->work_color)); 237273f53c4aSTejun Heo 237373f53c4aSTejun Heo /* this flush_color is finished, advance by one */ 237473f53c4aSTejun Heo wq->flush_color = work_next_color(wq->flush_color); 237573f53c4aSTejun Heo 237673f53c4aSTejun Heo /* one color has been freed, handle overflow queue */ 237773f53c4aSTejun Heo if (!list_empty(&wq->flusher_overflow)) { 237873f53c4aSTejun Heo /* 237973f53c4aSTejun Heo * Assign the same color to all overflowed 238073f53c4aSTejun Heo * flushers, advance work_color and append to 238173f53c4aSTejun Heo * flusher_queue. This is the start-to-wait 238273f53c4aSTejun Heo * phase for these overflowed flushers. 238373f53c4aSTejun Heo */ 238473f53c4aSTejun Heo list_for_each_entry(tmp, &wq->flusher_overflow, list) 238573f53c4aSTejun Heo tmp->flush_color = wq->work_color; 238673f53c4aSTejun Heo 238773f53c4aSTejun Heo wq->work_color = work_next_color(wq->work_color); 238873f53c4aSTejun Heo 238973f53c4aSTejun Heo list_splice_tail_init(&wq->flusher_overflow, 239073f53c4aSTejun Heo &wq->flusher_queue); 239173f53c4aSTejun Heo flush_workqueue_prep_cwqs(wq, -1, wq->work_color); 239273f53c4aSTejun Heo } 239373f53c4aSTejun Heo 239473f53c4aSTejun Heo if (list_empty(&wq->flusher_queue)) { 239573f53c4aSTejun Heo BUG_ON(wq->flush_color != wq->work_color); 239673f53c4aSTejun Heo break; 239773f53c4aSTejun Heo } 239873f53c4aSTejun Heo 239973f53c4aSTejun Heo /* 240073f53c4aSTejun Heo * Need to flush more colors. Make the next flusher 240173f53c4aSTejun Heo * the new first flusher and arm cwqs. 240273f53c4aSTejun Heo */ 240373f53c4aSTejun Heo BUG_ON(wq->flush_color == wq->work_color); 240473f53c4aSTejun Heo BUG_ON(wq->flush_color != next->flush_color); 240573f53c4aSTejun Heo 240673f53c4aSTejun Heo list_del_init(&next->list); 240773f53c4aSTejun Heo wq->first_flusher = next; 240873f53c4aSTejun Heo 240973f53c4aSTejun Heo if (flush_workqueue_prep_cwqs(wq, wq->flush_color, -1)) 241073f53c4aSTejun Heo break; 241173f53c4aSTejun Heo 241273f53c4aSTejun Heo /* 241373f53c4aSTejun Heo * Meh... this color is already done, clear first 241473f53c4aSTejun Heo * flusher and repeat cascading. 241573f53c4aSTejun Heo */ 241673f53c4aSTejun Heo wq->first_flusher = NULL; 241773f53c4aSTejun Heo } 241873f53c4aSTejun Heo 241973f53c4aSTejun Heo out_unlock: 242073f53c4aSTejun Heo mutex_unlock(&wq->flush_mutex); 24211da177e4SLinus Torvalds } 2422ae90dd5dSDave Jones EXPORT_SYMBOL_GPL(flush_workqueue); 24231da177e4SLinus Torvalds 24249c5a2ba7STejun Heo /** 24259c5a2ba7STejun Heo * drain_workqueue - drain a workqueue 24269c5a2ba7STejun Heo * @wq: workqueue to drain 24279c5a2ba7STejun Heo * 24289c5a2ba7STejun Heo * Wait until the workqueue becomes empty. While draining is in progress, 24299c5a2ba7STejun Heo * only chain queueing is allowed. IOW, only currently pending or running 24309c5a2ba7STejun Heo * work items on @wq can queue further work items on it. @wq is flushed 24319c5a2ba7STejun Heo * repeatedly until it becomes empty. The number of flushing is detemined 24329c5a2ba7STejun Heo * by the depth of chaining and should be relatively short. Whine if it 24339c5a2ba7STejun Heo * takes too long. 24349c5a2ba7STejun Heo */ 24359c5a2ba7STejun Heo void drain_workqueue(struct workqueue_struct *wq) 24369c5a2ba7STejun Heo { 24379c5a2ba7STejun Heo unsigned int flush_cnt = 0; 24389c5a2ba7STejun Heo unsigned int cpu; 24399c5a2ba7STejun Heo 24409c5a2ba7STejun Heo /* 24419c5a2ba7STejun Heo * __queue_work() needs to test whether there are drainers, is much 24429c5a2ba7STejun Heo * hotter than drain_workqueue() and already looks at @wq->flags. 24439c5a2ba7STejun Heo * Use WQ_DRAINING so that queue doesn't have to check nr_drainers. 24449c5a2ba7STejun Heo */ 24459c5a2ba7STejun Heo spin_lock(&workqueue_lock); 24469c5a2ba7STejun Heo if (!wq->nr_drainers++) 24479c5a2ba7STejun Heo wq->flags |= WQ_DRAINING; 24489c5a2ba7STejun Heo spin_unlock(&workqueue_lock); 24499c5a2ba7STejun Heo reflush: 24509c5a2ba7STejun Heo flush_workqueue(wq); 24519c5a2ba7STejun Heo 24529c5a2ba7STejun Heo for_each_cwq_cpu(cpu, wq) { 24539c5a2ba7STejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 2454fa2563e4SThomas Tuttle bool drained; 24559c5a2ba7STejun Heo 2456bd7bdd43STejun Heo spin_lock_irq(&cwq->pool->gcwq->lock); 2457fa2563e4SThomas Tuttle drained = !cwq->nr_active && list_empty(&cwq->delayed_works); 2458bd7bdd43STejun Heo spin_unlock_irq(&cwq->pool->gcwq->lock); 2459fa2563e4SThomas Tuttle 2460fa2563e4SThomas Tuttle if (drained) 24619c5a2ba7STejun Heo continue; 24629c5a2ba7STejun Heo 24639c5a2ba7STejun Heo if (++flush_cnt == 10 || 24649c5a2ba7STejun Heo (flush_cnt % 100 == 0 && flush_cnt <= 1000)) 24659c5a2ba7STejun Heo pr_warning("workqueue %s: flush on destruction isn't complete after %u tries\n", 24669c5a2ba7STejun Heo wq->name, flush_cnt); 24679c5a2ba7STejun Heo goto reflush; 24689c5a2ba7STejun Heo } 24699c5a2ba7STejun Heo 24709c5a2ba7STejun Heo spin_lock(&workqueue_lock); 24719c5a2ba7STejun Heo if (!--wq->nr_drainers) 24729c5a2ba7STejun Heo wq->flags &= ~WQ_DRAINING; 24739c5a2ba7STejun Heo spin_unlock(&workqueue_lock); 24749c5a2ba7STejun Heo } 24759c5a2ba7STejun Heo EXPORT_SYMBOL_GPL(drain_workqueue); 24769c5a2ba7STejun Heo 2477baf59022STejun Heo static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr, 2478baf59022STejun Heo bool wait_executing) 2479baf59022STejun Heo { 2480baf59022STejun Heo struct worker *worker = NULL; 2481baf59022STejun Heo struct global_cwq *gcwq; 2482baf59022STejun Heo struct cpu_workqueue_struct *cwq; 2483baf59022STejun Heo 2484baf59022STejun Heo might_sleep(); 2485baf59022STejun Heo gcwq = get_work_gcwq(work); 2486baf59022STejun Heo if (!gcwq) 2487baf59022STejun Heo return false; 2488baf59022STejun Heo 2489baf59022STejun Heo spin_lock_irq(&gcwq->lock); 2490baf59022STejun Heo if (!list_empty(&work->entry)) { 2491baf59022STejun Heo /* 2492baf59022STejun Heo * See the comment near try_to_grab_pending()->smp_rmb(). 2493baf59022STejun Heo * If it was re-queued to a different gcwq under us, we 2494baf59022STejun Heo * are not going to wait. 2495baf59022STejun Heo */ 2496baf59022STejun Heo smp_rmb(); 2497baf59022STejun Heo cwq = get_work_cwq(work); 2498bd7bdd43STejun Heo if (unlikely(!cwq || gcwq != cwq->pool->gcwq)) 2499baf59022STejun Heo goto already_gone; 2500baf59022STejun Heo } else if (wait_executing) { 2501baf59022STejun Heo worker = find_worker_executing_work(gcwq, work); 2502baf59022STejun Heo if (!worker) 2503baf59022STejun Heo goto already_gone; 2504baf59022STejun Heo cwq = worker->current_cwq; 2505baf59022STejun Heo } else 2506baf59022STejun Heo goto already_gone; 2507baf59022STejun Heo 2508baf59022STejun Heo insert_wq_barrier(cwq, barr, work, worker); 2509baf59022STejun Heo spin_unlock_irq(&gcwq->lock); 2510baf59022STejun Heo 2511e159489bSTejun Heo /* 2512e159489bSTejun Heo * If @max_active is 1 or rescuer is in use, flushing another work 2513e159489bSTejun Heo * item on the same workqueue may lead to deadlock. Make sure the 2514e159489bSTejun Heo * flusher is not running on the same workqueue by verifying write 2515e159489bSTejun Heo * access. 2516e159489bSTejun Heo */ 2517e159489bSTejun Heo if (cwq->wq->saved_max_active == 1 || cwq->wq->flags & WQ_RESCUER) 2518baf59022STejun Heo lock_map_acquire(&cwq->wq->lockdep_map); 2519e159489bSTejun Heo else 2520e159489bSTejun Heo lock_map_acquire_read(&cwq->wq->lockdep_map); 2521baf59022STejun Heo lock_map_release(&cwq->wq->lockdep_map); 2522e159489bSTejun Heo 2523baf59022STejun Heo return true; 2524baf59022STejun Heo already_gone: 2525baf59022STejun Heo spin_unlock_irq(&gcwq->lock); 2526baf59022STejun Heo return false; 2527baf59022STejun Heo } 2528baf59022STejun Heo 2529db700897SOleg Nesterov /** 2530401a8d04STejun Heo * flush_work - wait for a work to finish executing the last queueing instance 2531401a8d04STejun Heo * @work: the work to flush 2532db700897SOleg Nesterov * 2533401a8d04STejun Heo * Wait until @work has finished execution. This function considers 2534401a8d04STejun Heo * only the last queueing instance of @work. If @work has been 2535401a8d04STejun Heo * enqueued across different CPUs on a non-reentrant workqueue or on 2536401a8d04STejun Heo * multiple workqueues, @work might still be executing on return on 2537401a8d04STejun Heo * some of the CPUs from earlier queueing. 2538a67da70dSOleg Nesterov * 2539401a8d04STejun Heo * If @work was queued only on a non-reentrant, ordered or unbound 2540401a8d04STejun Heo * workqueue, @work is guaranteed to be idle on return if it hasn't 2541401a8d04STejun Heo * been requeued since flush started. 2542401a8d04STejun Heo * 2543401a8d04STejun Heo * RETURNS: 2544401a8d04STejun Heo * %true if flush_work() waited for the work to finish execution, 2545401a8d04STejun Heo * %false if it was already idle. 2546db700897SOleg Nesterov */ 2547401a8d04STejun Heo bool flush_work(struct work_struct *work) 2548db700897SOleg Nesterov { 2549db700897SOleg Nesterov struct wq_barrier barr; 2550db700897SOleg Nesterov 25510976dfc1SStephen Boyd lock_map_acquire(&work->lockdep_map); 25520976dfc1SStephen Boyd lock_map_release(&work->lockdep_map); 25530976dfc1SStephen Boyd 2554baf59022STejun Heo if (start_flush_work(work, &barr, true)) { 2555db700897SOleg Nesterov wait_for_completion(&barr.done); 2556dc186ad7SThomas Gleixner destroy_work_on_stack(&barr.work); 2557401a8d04STejun Heo return true; 2558baf59022STejun Heo } else 2559401a8d04STejun Heo return false; 2560db700897SOleg Nesterov } 2561db700897SOleg Nesterov EXPORT_SYMBOL_GPL(flush_work); 2562db700897SOleg Nesterov 2563401a8d04STejun Heo static bool wait_on_cpu_work(struct global_cwq *gcwq, struct work_struct *work) 2564401a8d04STejun Heo { 2565401a8d04STejun Heo struct wq_barrier barr; 2566401a8d04STejun Heo struct worker *worker; 2567401a8d04STejun Heo 2568401a8d04STejun Heo spin_lock_irq(&gcwq->lock); 2569401a8d04STejun Heo 2570401a8d04STejun Heo worker = find_worker_executing_work(gcwq, work); 2571401a8d04STejun Heo if (unlikely(worker)) 2572401a8d04STejun Heo insert_wq_barrier(worker->current_cwq, &barr, work, worker); 2573401a8d04STejun Heo 2574401a8d04STejun Heo spin_unlock_irq(&gcwq->lock); 2575401a8d04STejun Heo 2576401a8d04STejun Heo if (unlikely(worker)) { 2577401a8d04STejun Heo wait_for_completion(&barr.done); 2578401a8d04STejun Heo destroy_work_on_stack(&barr.work); 2579401a8d04STejun Heo return true; 2580401a8d04STejun Heo } else 2581401a8d04STejun Heo return false; 2582401a8d04STejun Heo } 2583401a8d04STejun Heo 2584401a8d04STejun Heo static bool wait_on_work(struct work_struct *work) 2585401a8d04STejun Heo { 2586401a8d04STejun Heo bool ret = false; 2587401a8d04STejun Heo int cpu; 2588401a8d04STejun Heo 2589401a8d04STejun Heo might_sleep(); 2590401a8d04STejun Heo 2591401a8d04STejun Heo lock_map_acquire(&work->lockdep_map); 2592401a8d04STejun Heo lock_map_release(&work->lockdep_map); 2593401a8d04STejun Heo 2594401a8d04STejun Heo for_each_gcwq_cpu(cpu) 2595401a8d04STejun Heo ret |= wait_on_cpu_work(get_gcwq(cpu), work); 2596401a8d04STejun Heo return ret; 2597401a8d04STejun Heo } 2598401a8d04STejun Heo 259909383498STejun Heo /** 260009383498STejun Heo * flush_work_sync - wait until a work has finished execution 260109383498STejun Heo * @work: the work to flush 260209383498STejun Heo * 260309383498STejun Heo * Wait until @work has finished execution. On return, it's 260409383498STejun Heo * guaranteed that all queueing instances of @work which happened 260509383498STejun Heo * before this function is called are finished. In other words, if 260609383498STejun Heo * @work hasn't been requeued since this function was called, @work is 260709383498STejun Heo * guaranteed to be idle on return. 260809383498STejun Heo * 260909383498STejun Heo * RETURNS: 261009383498STejun Heo * %true if flush_work_sync() waited for the work to finish execution, 261109383498STejun Heo * %false if it was already idle. 261209383498STejun Heo */ 261309383498STejun Heo bool flush_work_sync(struct work_struct *work) 261409383498STejun Heo { 261509383498STejun Heo struct wq_barrier barr; 261609383498STejun Heo bool pending, waited; 261709383498STejun Heo 261809383498STejun Heo /* we'll wait for executions separately, queue barr only if pending */ 261909383498STejun Heo pending = start_flush_work(work, &barr, false); 262009383498STejun Heo 262109383498STejun Heo /* wait for executions to finish */ 262209383498STejun Heo waited = wait_on_work(work); 262309383498STejun Heo 262409383498STejun Heo /* wait for the pending one */ 262509383498STejun Heo if (pending) { 262609383498STejun Heo wait_for_completion(&barr.done); 262709383498STejun Heo destroy_work_on_stack(&barr.work); 262809383498STejun Heo } 262909383498STejun Heo 263009383498STejun Heo return pending || waited; 263109383498STejun Heo } 263209383498STejun Heo EXPORT_SYMBOL_GPL(flush_work_sync); 263309383498STejun Heo 26346e84d644SOleg Nesterov /* 26351f1f642eSOleg Nesterov * Upon a successful return (>= 0), the caller "owns" WORK_STRUCT_PENDING bit, 26366e84d644SOleg Nesterov * so this work can't be re-armed in any way. 26376e84d644SOleg Nesterov */ 26386e84d644SOleg Nesterov static int try_to_grab_pending(struct work_struct *work) 26396e84d644SOleg Nesterov { 26408b03ae3cSTejun Heo struct global_cwq *gcwq; 26411f1f642eSOleg Nesterov int ret = -1; 26426e84d644SOleg Nesterov 264322df02bbSTejun Heo if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) 26441f1f642eSOleg Nesterov return 0; 26456e84d644SOleg Nesterov 26466e84d644SOleg Nesterov /* 26476e84d644SOleg Nesterov * The queueing is in progress, or it is already queued. Try to 26486e84d644SOleg Nesterov * steal it from ->worklist without clearing WORK_STRUCT_PENDING. 26496e84d644SOleg Nesterov */ 26507a22ad75STejun Heo gcwq = get_work_gcwq(work); 26517a22ad75STejun Heo if (!gcwq) 26526e84d644SOleg Nesterov return ret; 26536e84d644SOleg Nesterov 26548b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 26556e84d644SOleg Nesterov if (!list_empty(&work->entry)) { 26566e84d644SOleg Nesterov /* 26577a22ad75STejun Heo * This work is queued, but perhaps we locked the wrong gcwq. 26586e84d644SOleg Nesterov * In that case we must see the new value after rmb(), see 26596e84d644SOleg Nesterov * insert_work()->wmb(). 26606e84d644SOleg Nesterov */ 26616e84d644SOleg Nesterov smp_rmb(); 26627a22ad75STejun Heo if (gcwq == get_work_gcwq(work)) { 2663dc186ad7SThomas Gleixner debug_work_deactivate(work); 26646e84d644SOleg Nesterov list_del_init(&work->entry); 26657a22ad75STejun Heo cwq_dec_nr_in_flight(get_work_cwq(work), 26668a2e8e5dSTejun Heo get_work_color(work), 26678a2e8e5dSTejun Heo *work_data_bits(work) & WORK_STRUCT_DELAYED); 26686e84d644SOleg Nesterov ret = 1; 26696e84d644SOleg Nesterov } 26706e84d644SOleg Nesterov } 26718b03ae3cSTejun Heo spin_unlock_irq(&gcwq->lock); 26726e84d644SOleg Nesterov 26736e84d644SOleg Nesterov return ret; 26746e84d644SOleg Nesterov } 26756e84d644SOleg Nesterov 2676401a8d04STejun Heo static bool __cancel_work_timer(struct work_struct *work, 26771f1f642eSOleg Nesterov struct timer_list* timer) 26781f1f642eSOleg Nesterov { 26791f1f642eSOleg Nesterov int ret; 26801f1f642eSOleg Nesterov 26811f1f642eSOleg Nesterov do { 26821f1f642eSOleg Nesterov ret = (timer && likely(del_timer(timer))); 26831f1f642eSOleg Nesterov if (!ret) 26841f1f642eSOleg Nesterov ret = try_to_grab_pending(work); 26851f1f642eSOleg Nesterov wait_on_work(work); 26861f1f642eSOleg Nesterov } while (unlikely(ret < 0)); 26871f1f642eSOleg Nesterov 26887a22ad75STejun Heo clear_work_data(work); 26891f1f642eSOleg Nesterov return ret; 26901f1f642eSOleg Nesterov } 26911f1f642eSOleg Nesterov 26926e84d644SOleg Nesterov /** 2693401a8d04STejun Heo * cancel_work_sync - cancel a work and wait for it to finish 2694401a8d04STejun Heo * @work: the work to cancel 26956e84d644SOleg Nesterov * 2696401a8d04STejun Heo * Cancel @work and wait for its execution to finish. This function 2697401a8d04STejun Heo * can be used even if the work re-queues itself or migrates to 2698401a8d04STejun Heo * another workqueue. On return from this function, @work is 2699401a8d04STejun Heo * guaranteed to be not pending or executing on any CPU. 27001f1f642eSOleg Nesterov * 2701401a8d04STejun Heo * cancel_work_sync(&delayed_work->work) must not be used for 2702401a8d04STejun Heo * delayed_work's. Use cancel_delayed_work_sync() instead. 27036e84d644SOleg Nesterov * 2704401a8d04STejun Heo * The caller must ensure that the workqueue on which @work was last 27056e84d644SOleg Nesterov * queued can't be destroyed before this function returns. 2706401a8d04STejun Heo * 2707401a8d04STejun Heo * RETURNS: 2708401a8d04STejun Heo * %true if @work was pending, %false otherwise. 27096e84d644SOleg Nesterov */ 2710401a8d04STejun Heo bool cancel_work_sync(struct work_struct *work) 27116e84d644SOleg Nesterov { 27121f1f642eSOleg Nesterov return __cancel_work_timer(work, NULL); 2713b89deed3SOleg Nesterov } 271428e53bddSOleg Nesterov EXPORT_SYMBOL_GPL(cancel_work_sync); 2715b89deed3SOleg Nesterov 27166e84d644SOleg Nesterov /** 2717401a8d04STejun Heo * flush_delayed_work - wait for a dwork to finish executing the last queueing 2718401a8d04STejun Heo * @dwork: the delayed work to flush 27196e84d644SOleg Nesterov * 2720401a8d04STejun Heo * Delayed timer is cancelled and the pending work is queued for 2721401a8d04STejun Heo * immediate execution. Like flush_work(), this function only 2722401a8d04STejun Heo * considers the last queueing instance of @dwork. 27231f1f642eSOleg Nesterov * 2724401a8d04STejun Heo * RETURNS: 2725401a8d04STejun Heo * %true if flush_work() waited for the work to finish execution, 2726401a8d04STejun Heo * %false if it was already idle. 27276e84d644SOleg Nesterov */ 2728401a8d04STejun Heo bool flush_delayed_work(struct delayed_work *dwork) 2729401a8d04STejun Heo { 2730401a8d04STejun Heo if (del_timer_sync(&dwork->timer)) 2731401a8d04STejun Heo __queue_work(raw_smp_processor_id(), 2732401a8d04STejun Heo get_work_cwq(&dwork->work)->wq, &dwork->work); 2733401a8d04STejun Heo return flush_work(&dwork->work); 2734401a8d04STejun Heo } 2735401a8d04STejun Heo EXPORT_SYMBOL(flush_delayed_work); 2736401a8d04STejun Heo 2737401a8d04STejun Heo /** 273809383498STejun Heo * flush_delayed_work_sync - wait for a dwork to finish 273909383498STejun Heo * @dwork: the delayed work to flush 274009383498STejun Heo * 274109383498STejun Heo * Delayed timer is cancelled and the pending work is queued for 274209383498STejun Heo * execution immediately. Other than timer handling, its behavior 274309383498STejun Heo * is identical to flush_work_sync(). 274409383498STejun Heo * 274509383498STejun Heo * RETURNS: 274609383498STejun Heo * %true if flush_work_sync() waited for the work to finish execution, 274709383498STejun Heo * %false if it was already idle. 274809383498STejun Heo */ 274909383498STejun Heo bool flush_delayed_work_sync(struct delayed_work *dwork) 275009383498STejun Heo { 275109383498STejun Heo if (del_timer_sync(&dwork->timer)) 275209383498STejun Heo __queue_work(raw_smp_processor_id(), 275309383498STejun Heo get_work_cwq(&dwork->work)->wq, &dwork->work); 275409383498STejun Heo return flush_work_sync(&dwork->work); 275509383498STejun Heo } 275609383498STejun Heo EXPORT_SYMBOL(flush_delayed_work_sync); 275709383498STejun Heo 275809383498STejun Heo /** 2759401a8d04STejun Heo * cancel_delayed_work_sync - cancel a delayed work and wait for it to finish 2760401a8d04STejun Heo * @dwork: the delayed work cancel 2761401a8d04STejun Heo * 2762401a8d04STejun Heo * This is cancel_work_sync() for delayed works. 2763401a8d04STejun Heo * 2764401a8d04STejun Heo * RETURNS: 2765401a8d04STejun Heo * %true if @dwork was pending, %false otherwise. 2766401a8d04STejun Heo */ 2767401a8d04STejun Heo bool cancel_delayed_work_sync(struct delayed_work *dwork) 27686e84d644SOleg Nesterov { 27691f1f642eSOleg Nesterov return __cancel_work_timer(&dwork->work, &dwork->timer); 27706e84d644SOleg Nesterov } 2771f5a421a4SOleg Nesterov EXPORT_SYMBOL(cancel_delayed_work_sync); 27721da177e4SLinus Torvalds 27730fcb78c2SRolf Eike Beer /** 27740fcb78c2SRolf Eike Beer * schedule_work - put work task in global workqueue 27750fcb78c2SRolf Eike Beer * @work: job to be done 27760fcb78c2SRolf Eike Beer * 27775b0f437dSBart Van Assche * Returns zero if @work was already on the kernel-global workqueue and 27785b0f437dSBart Van Assche * non-zero otherwise. 27795b0f437dSBart Van Assche * 27805b0f437dSBart Van Assche * This puts a job in the kernel-global workqueue if it was not already 27815b0f437dSBart Van Assche * queued and leaves it in the same position on the kernel-global 27825b0f437dSBart Van Assche * workqueue otherwise. 27830fcb78c2SRolf Eike Beer */ 27847ad5b3a5SHarvey Harrison int schedule_work(struct work_struct *work) 27851da177e4SLinus Torvalds { 2786d320c038STejun Heo return queue_work(system_wq, work); 27871da177e4SLinus Torvalds } 2788ae90dd5dSDave Jones EXPORT_SYMBOL(schedule_work); 27891da177e4SLinus Torvalds 2790c1a220e7SZhang Rui /* 2791c1a220e7SZhang Rui * schedule_work_on - put work task on a specific cpu 2792c1a220e7SZhang Rui * @cpu: cpu to put the work task on 2793c1a220e7SZhang Rui * @work: job to be done 2794c1a220e7SZhang Rui * 2795c1a220e7SZhang Rui * This puts a job on a specific cpu 2796c1a220e7SZhang Rui */ 2797c1a220e7SZhang Rui int schedule_work_on(int cpu, struct work_struct *work) 2798c1a220e7SZhang Rui { 2799d320c038STejun Heo return queue_work_on(cpu, system_wq, work); 2800c1a220e7SZhang Rui } 2801c1a220e7SZhang Rui EXPORT_SYMBOL(schedule_work_on); 2802c1a220e7SZhang Rui 28030fcb78c2SRolf Eike Beer /** 28040fcb78c2SRolf Eike Beer * schedule_delayed_work - put work task in global workqueue after delay 280552bad64dSDavid Howells * @dwork: job to be done 280652bad64dSDavid Howells * @delay: number of jiffies to wait or 0 for immediate execution 28070fcb78c2SRolf Eike Beer * 28080fcb78c2SRolf Eike Beer * After waiting for a given time this puts a job in the kernel-global 28090fcb78c2SRolf Eike Beer * workqueue. 28100fcb78c2SRolf Eike Beer */ 28117ad5b3a5SHarvey Harrison int schedule_delayed_work(struct delayed_work *dwork, 281282f67cd9SIngo Molnar unsigned long delay) 28131da177e4SLinus Torvalds { 2814d320c038STejun Heo return queue_delayed_work(system_wq, dwork, delay); 28151da177e4SLinus Torvalds } 2816ae90dd5dSDave Jones EXPORT_SYMBOL(schedule_delayed_work); 28171da177e4SLinus Torvalds 28180fcb78c2SRolf Eike Beer /** 28190fcb78c2SRolf Eike Beer * schedule_delayed_work_on - queue work in global workqueue on CPU after delay 28200fcb78c2SRolf Eike Beer * @cpu: cpu to use 282152bad64dSDavid Howells * @dwork: job to be done 28220fcb78c2SRolf Eike Beer * @delay: number of jiffies to wait 28230fcb78c2SRolf Eike Beer * 28240fcb78c2SRolf Eike Beer * After waiting for a given time this puts a job in the kernel-global 28250fcb78c2SRolf Eike Beer * workqueue on the specified CPU. 28260fcb78c2SRolf Eike Beer */ 28271da177e4SLinus Torvalds int schedule_delayed_work_on(int cpu, 282852bad64dSDavid Howells struct delayed_work *dwork, unsigned long delay) 28291da177e4SLinus Torvalds { 2830d320c038STejun Heo return queue_delayed_work_on(cpu, system_wq, dwork, delay); 28311da177e4SLinus Torvalds } 2832ae90dd5dSDave Jones EXPORT_SYMBOL(schedule_delayed_work_on); 28331da177e4SLinus Torvalds 2834b6136773SAndrew Morton /** 283531ddd871STejun Heo * schedule_on_each_cpu - execute a function synchronously on each online CPU 2836b6136773SAndrew Morton * @func: the function to call 2837b6136773SAndrew Morton * 283831ddd871STejun Heo * schedule_on_each_cpu() executes @func on each online CPU using the 283931ddd871STejun Heo * system workqueue and blocks until all CPUs have completed. 2840b6136773SAndrew Morton * schedule_on_each_cpu() is very slow. 284131ddd871STejun Heo * 284231ddd871STejun Heo * RETURNS: 284331ddd871STejun Heo * 0 on success, -errno on failure. 2844b6136773SAndrew Morton */ 284565f27f38SDavid Howells int schedule_on_each_cpu(work_func_t func) 284615316ba8SChristoph Lameter { 284715316ba8SChristoph Lameter int cpu; 284838f51568SNamhyung Kim struct work_struct __percpu *works; 284915316ba8SChristoph Lameter 2850b6136773SAndrew Morton works = alloc_percpu(struct work_struct); 2851b6136773SAndrew Morton if (!works) 285215316ba8SChristoph Lameter return -ENOMEM; 2853b6136773SAndrew Morton 285495402b38SGautham R Shenoy get_online_cpus(); 285593981800STejun Heo 285615316ba8SChristoph Lameter for_each_online_cpu(cpu) { 28579bfb1839SIngo Molnar struct work_struct *work = per_cpu_ptr(works, cpu); 28589bfb1839SIngo Molnar 28599bfb1839SIngo Molnar INIT_WORK(work, func); 28608de6d308SOleg Nesterov schedule_work_on(cpu, work); 286115316ba8SChristoph Lameter } 286293981800STejun Heo 286393981800STejun Heo for_each_online_cpu(cpu) 28648616a89aSOleg Nesterov flush_work(per_cpu_ptr(works, cpu)); 286593981800STejun Heo 286695402b38SGautham R Shenoy put_online_cpus(); 2867b6136773SAndrew Morton free_percpu(works); 286815316ba8SChristoph Lameter return 0; 286915316ba8SChristoph Lameter } 287015316ba8SChristoph Lameter 2871eef6a7d5SAlan Stern /** 2872eef6a7d5SAlan Stern * flush_scheduled_work - ensure that any scheduled work has run to completion. 2873eef6a7d5SAlan Stern * 2874eef6a7d5SAlan Stern * Forces execution of the kernel-global workqueue and blocks until its 2875eef6a7d5SAlan Stern * completion. 2876eef6a7d5SAlan Stern * 2877eef6a7d5SAlan Stern * Think twice before calling this function! It's very easy to get into 2878eef6a7d5SAlan Stern * trouble if you don't take great care. Either of the following situations 2879eef6a7d5SAlan Stern * will lead to deadlock: 2880eef6a7d5SAlan Stern * 2881eef6a7d5SAlan Stern * One of the work items currently on the workqueue needs to acquire 2882eef6a7d5SAlan Stern * a lock held by your code or its caller. 2883eef6a7d5SAlan Stern * 2884eef6a7d5SAlan Stern * Your code is running in the context of a work routine. 2885eef6a7d5SAlan Stern * 2886eef6a7d5SAlan Stern * They will be detected by lockdep when they occur, but the first might not 2887eef6a7d5SAlan Stern * occur very often. It depends on what work items are on the workqueue and 2888eef6a7d5SAlan Stern * what locks they need, which you have no control over. 2889eef6a7d5SAlan Stern * 2890eef6a7d5SAlan Stern * In most situations flushing the entire workqueue is overkill; you merely 2891eef6a7d5SAlan Stern * need to know that a particular work item isn't queued and isn't running. 2892eef6a7d5SAlan Stern * In such cases you should use cancel_delayed_work_sync() or 2893eef6a7d5SAlan Stern * cancel_work_sync() instead. 2894eef6a7d5SAlan Stern */ 28951da177e4SLinus Torvalds void flush_scheduled_work(void) 28961da177e4SLinus Torvalds { 2897d320c038STejun Heo flush_workqueue(system_wq); 28981da177e4SLinus Torvalds } 2899ae90dd5dSDave Jones EXPORT_SYMBOL(flush_scheduled_work); 29001da177e4SLinus Torvalds 29011da177e4SLinus Torvalds /** 29021fa44ecaSJames Bottomley * execute_in_process_context - reliably execute the routine with user context 29031fa44ecaSJames Bottomley * @fn: the function to execute 29041fa44ecaSJames Bottomley * @ew: guaranteed storage for the execute work structure (must 29051fa44ecaSJames Bottomley * be available when the work executes) 29061fa44ecaSJames Bottomley * 29071fa44ecaSJames Bottomley * Executes the function immediately if process context is available, 29081fa44ecaSJames Bottomley * otherwise schedules the function for delayed execution. 29091fa44ecaSJames Bottomley * 29101fa44ecaSJames Bottomley * Returns: 0 - function was executed 29111fa44ecaSJames Bottomley * 1 - function was scheduled for execution 29121fa44ecaSJames Bottomley */ 291365f27f38SDavid Howells int execute_in_process_context(work_func_t fn, struct execute_work *ew) 29141fa44ecaSJames Bottomley { 29151fa44ecaSJames Bottomley if (!in_interrupt()) { 291665f27f38SDavid Howells fn(&ew->work); 29171fa44ecaSJames Bottomley return 0; 29181fa44ecaSJames Bottomley } 29191fa44ecaSJames Bottomley 292065f27f38SDavid Howells INIT_WORK(&ew->work, fn); 29211fa44ecaSJames Bottomley schedule_work(&ew->work); 29221fa44ecaSJames Bottomley 29231fa44ecaSJames Bottomley return 1; 29241fa44ecaSJames Bottomley } 29251fa44ecaSJames Bottomley EXPORT_SYMBOL_GPL(execute_in_process_context); 29261fa44ecaSJames Bottomley 29271da177e4SLinus Torvalds int keventd_up(void) 29281da177e4SLinus Torvalds { 2929d320c038STejun Heo return system_wq != NULL; 29301da177e4SLinus Torvalds } 29311da177e4SLinus Torvalds 2932bdbc5dd7STejun Heo static int alloc_cwqs(struct workqueue_struct *wq) 29331da177e4SLinus Torvalds { 29343af24433SOleg Nesterov /* 29350f900049STejun Heo * cwqs are forced aligned according to WORK_STRUCT_FLAG_BITS. 29360f900049STejun Heo * Make sure that the alignment isn't lower than that of 29370f900049STejun Heo * unsigned long long. 29383af24433SOleg Nesterov */ 29390f900049STejun Heo const size_t size = sizeof(struct cpu_workqueue_struct); 29400f900049STejun Heo const size_t align = max_t(size_t, 1 << WORK_STRUCT_FLAG_BITS, 29410f900049STejun Heo __alignof__(unsigned long long)); 29423af24433SOleg Nesterov 2943e06ffa1eSLai Jiangshan if (!(wq->flags & WQ_UNBOUND)) 2944f3421797STejun Heo wq->cpu_wq.pcpu = __alloc_percpu(size, align); 2945931ac77eSTejun Heo else { 29460f900049STejun Heo void *ptr; 2947e1d8aa9fSFrederic Weisbecker 29480f900049STejun Heo /* 2949f3421797STejun Heo * Allocate enough room to align cwq and put an extra 2950f3421797STejun Heo * pointer at the end pointing back to the originally 2951f3421797STejun Heo * allocated pointer which will be used for free. 29520f900049STejun Heo */ 2953bdbc5dd7STejun Heo ptr = kzalloc(size + align + sizeof(void *), GFP_KERNEL); 2954bdbc5dd7STejun Heo if (ptr) { 2955bdbc5dd7STejun Heo wq->cpu_wq.single = PTR_ALIGN(ptr, align); 2956bdbc5dd7STejun Heo *(void **)(wq->cpu_wq.single + 1) = ptr; 2957bdbc5dd7STejun Heo } 29583af24433SOleg Nesterov } 29593af24433SOleg Nesterov 29600415b00dSTejun Heo /* just in case, make sure it's actually aligned */ 2961bdbc5dd7STejun Heo BUG_ON(!IS_ALIGNED(wq->cpu_wq.v, align)); 2962bdbc5dd7STejun Heo return wq->cpu_wq.v ? 0 : -ENOMEM; 29630f900049STejun Heo } 29640f900049STejun Heo 2965bdbc5dd7STejun Heo static void free_cwqs(struct workqueue_struct *wq) 296606ba38a9SOleg Nesterov { 2967e06ffa1eSLai Jiangshan if (!(wq->flags & WQ_UNBOUND)) 2968bdbc5dd7STejun Heo free_percpu(wq->cpu_wq.pcpu); 2969f3421797STejun Heo else if (wq->cpu_wq.single) { 2970f3421797STejun Heo /* the pointer to free is stored right after the cwq */ 2971f3421797STejun Heo kfree(*(void **)(wq->cpu_wq.single + 1)); 297206ba38a9SOleg Nesterov } 297306ba38a9SOleg Nesterov } 297406ba38a9SOleg Nesterov 2975f3421797STejun Heo static int wq_clamp_max_active(int max_active, unsigned int flags, 2976f3421797STejun Heo const char *name) 2977b71ab8c2STejun Heo { 2978f3421797STejun Heo int lim = flags & WQ_UNBOUND ? WQ_UNBOUND_MAX_ACTIVE : WQ_MAX_ACTIVE; 2979f3421797STejun Heo 2980f3421797STejun Heo if (max_active < 1 || max_active > lim) 2981b71ab8c2STejun Heo printk(KERN_WARNING "workqueue: max_active %d requested for %s " 2982b71ab8c2STejun Heo "is out of range, clamping between %d and %d\n", 2983f3421797STejun Heo max_active, name, 1, lim); 2984b71ab8c2STejun Heo 2985f3421797STejun Heo return clamp_val(max_active, 1, lim); 2986b71ab8c2STejun Heo } 2987b71ab8c2STejun Heo 2988b196be89STejun Heo struct workqueue_struct *__alloc_workqueue_key(const char *fmt, 298997e37d7bSTejun Heo unsigned int flags, 29901e19ffc6STejun Heo int max_active, 2991eb13ba87SJohannes Berg struct lock_class_key *key, 2992b196be89STejun Heo const char *lock_name, ...) 29933af24433SOleg Nesterov { 2994b196be89STejun Heo va_list args, args1; 29953af24433SOleg Nesterov struct workqueue_struct *wq; 2996c34056a3STejun Heo unsigned int cpu; 2997b196be89STejun Heo size_t namelen; 2998b196be89STejun Heo 2999b196be89STejun Heo /* determine namelen, allocate wq and format name */ 3000b196be89STejun Heo va_start(args, lock_name); 3001b196be89STejun Heo va_copy(args1, args); 3002b196be89STejun Heo namelen = vsnprintf(NULL, 0, fmt, args) + 1; 3003b196be89STejun Heo 3004b196be89STejun Heo wq = kzalloc(sizeof(*wq) + namelen, GFP_KERNEL); 3005b196be89STejun Heo if (!wq) 3006b196be89STejun Heo goto err; 3007b196be89STejun Heo 3008b196be89STejun Heo vsnprintf(wq->name, namelen, fmt, args1); 3009b196be89STejun Heo va_end(args); 3010b196be89STejun Heo va_end(args1); 30113af24433SOleg Nesterov 3012f3421797STejun Heo /* 30136370a6adSTejun Heo * Workqueues which may be used during memory reclaim should 30146370a6adSTejun Heo * have a rescuer to guarantee forward progress. 30156370a6adSTejun Heo */ 30166370a6adSTejun Heo if (flags & WQ_MEM_RECLAIM) 30176370a6adSTejun Heo flags |= WQ_RESCUER; 30186370a6adSTejun Heo 3019d320c038STejun Heo max_active = max_active ?: WQ_DFL_ACTIVE; 3020b196be89STejun Heo max_active = wq_clamp_max_active(max_active, flags, wq->name); 30213af24433SOleg Nesterov 3022b196be89STejun Heo /* init wq */ 302397e37d7bSTejun Heo wq->flags = flags; 3024a0a1a5fdSTejun Heo wq->saved_max_active = max_active; 302573f53c4aSTejun Heo mutex_init(&wq->flush_mutex); 302673f53c4aSTejun Heo atomic_set(&wq->nr_cwqs_to_flush, 0); 302773f53c4aSTejun Heo INIT_LIST_HEAD(&wq->flusher_queue); 302873f53c4aSTejun Heo INIT_LIST_HEAD(&wq->flusher_overflow); 30293af24433SOleg Nesterov 3030eb13ba87SJohannes Berg lockdep_init_map(&wq->lockdep_map, lock_name, key, 0); 3031cce1a165SOleg Nesterov INIT_LIST_HEAD(&wq->list); 30323af24433SOleg Nesterov 3033bdbc5dd7STejun Heo if (alloc_cwqs(wq) < 0) 3034bdbc5dd7STejun Heo goto err; 3035bdbc5dd7STejun Heo 3036f3421797STejun Heo for_each_cwq_cpu(cpu, wq) { 30371537663fSTejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 30388b03ae3cSTejun Heo struct global_cwq *gcwq = get_gcwq(cpu); 30391537663fSTejun Heo 30400f900049STejun Heo BUG_ON((unsigned long)cwq & WORK_STRUCT_FLAG_MASK); 3041bd7bdd43STejun Heo cwq->pool = &gcwq->pool; 3042c34056a3STejun Heo cwq->wq = wq; 304373f53c4aSTejun Heo cwq->flush_color = -1; 30441e19ffc6STejun Heo cwq->max_active = max_active; 30451e19ffc6STejun Heo INIT_LIST_HEAD(&cwq->delayed_works); 3046e22bee78STejun Heo } 30471537663fSTejun Heo 3048e22bee78STejun Heo if (flags & WQ_RESCUER) { 3049e22bee78STejun Heo struct worker *rescuer; 3050e22bee78STejun Heo 3051f2e005aaSTejun Heo if (!alloc_mayday_mask(&wq->mayday_mask, GFP_KERNEL)) 3052e22bee78STejun Heo goto err; 3053e22bee78STejun Heo 3054e22bee78STejun Heo wq->rescuer = rescuer = alloc_worker(); 3055e22bee78STejun Heo if (!rescuer) 3056e22bee78STejun Heo goto err; 3057e22bee78STejun Heo 3058b196be89STejun Heo rescuer->task = kthread_create(rescuer_thread, wq, "%s", 3059b196be89STejun Heo wq->name); 3060e22bee78STejun Heo if (IS_ERR(rescuer->task)) 3061e22bee78STejun Heo goto err; 3062e22bee78STejun Heo 3063e22bee78STejun Heo rescuer->task->flags |= PF_THREAD_BOUND; 3064e22bee78STejun Heo wake_up_process(rescuer->task); 30653af24433SOleg Nesterov } 30661537663fSTejun Heo 30673af24433SOleg Nesterov /* 3068a0a1a5fdSTejun Heo * workqueue_lock protects global freeze state and workqueues 3069a0a1a5fdSTejun Heo * list. Grab it, set max_active accordingly and add the new 3070a0a1a5fdSTejun Heo * workqueue to workqueues list. 30713af24433SOleg Nesterov */ 30723af24433SOleg Nesterov spin_lock(&workqueue_lock); 3073a0a1a5fdSTejun Heo 307458a69cb4STejun Heo if (workqueue_freezing && wq->flags & WQ_FREEZABLE) 3075f3421797STejun Heo for_each_cwq_cpu(cpu, wq) 3076a0a1a5fdSTejun Heo get_cwq(cpu, wq)->max_active = 0; 3077a0a1a5fdSTejun Heo 30783af24433SOleg Nesterov list_add(&wq->list, &workqueues); 3079a0a1a5fdSTejun Heo 30803af24433SOleg Nesterov spin_unlock(&workqueue_lock); 30813af24433SOleg Nesterov 30823af24433SOleg Nesterov return wq; 30834690c4abSTejun Heo err: 30844690c4abSTejun Heo if (wq) { 3085bdbc5dd7STejun Heo free_cwqs(wq); 3086f2e005aaSTejun Heo free_mayday_mask(wq->mayday_mask); 3087e22bee78STejun Heo kfree(wq->rescuer); 30884690c4abSTejun Heo kfree(wq); 30893af24433SOleg Nesterov } 30904690c4abSTejun Heo return NULL; 30911da177e4SLinus Torvalds } 3092d320c038STejun Heo EXPORT_SYMBOL_GPL(__alloc_workqueue_key); 30931da177e4SLinus Torvalds 30943af24433SOleg Nesterov /** 30953af24433SOleg Nesterov * destroy_workqueue - safely terminate a workqueue 30963af24433SOleg Nesterov * @wq: target workqueue 30973af24433SOleg Nesterov * 30983af24433SOleg Nesterov * Safely destroy a workqueue. All work currently pending will be done first. 30993af24433SOleg Nesterov */ 31003af24433SOleg Nesterov void destroy_workqueue(struct workqueue_struct *wq) 31013af24433SOleg Nesterov { 3102c8e55f36STejun Heo unsigned int cpu; 31033af24433SOleg Nesterov 31049c5a2ba7STejun Heo /* drain it before proceeding with destruction */ 31059c5a2ba7STejun Heo drain_workqueue(wq); 3106c8efcc25STejun Heo 3107a0a1a5fdSTejun Heo /* 3108a0a1a5fdSTejun Heo * wq list is used to freeze wq, remove from list after 3109a0a1a5fdSTejun Heo * flushing is complete in case freeze races us. 3110a0a1a5fdSTejun Heo */ 311195402b38SGautham R Shenoy spin_lock(&workqueue_lock); 31123af24433SOleg Nesterov list_del(&wq->list); 311395402b38SGautham R Shenoy spin_unlock(&workqueue_lock); 31143af24433SOleg Nesterov 3115e22bee78STejun Heo /* sanity check */ 3116f3421797STejun Heo for_each_cwq_cpu(cpu, wq) { 311773f53c4aSTejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 311873f53c4aSTejun Heo int i; 31193af24433SOleg Nesterov 312073f53c4aSTejun Heo for (i = 0; i < WORK_NR_COLORS; i++) 312173f53c4aSTejun Heo BUG_ON(cwq->nr_in_flight[i]); 31221e19ffc6STejun Heo BUG_ON(cwq->nr_active); 31231e19ffc6STejun Heo BUG_ON(!list_empty(&cwq->delayed_works)); 312473f53c4aSTejun Heo } 31251537663fSTejun Heo 3126e22bee78STejun Heo if (wq->flags & WQ_RESCUER) { 3127e22bee78STejun Heo kthread_stop(wq->rescuer->task); 3128f2e005aaSTejun Heo free_mayday_mask(wq->mayday_mask); 31298d9df9f0SXiaotian Feng kfree(wq->rescuer); 3130e22bee78STejun Heo } 3131e22bee78STejun Heo 3132bdbc5dd7STejun Heo free_cwqs(wq); 31333af24433SOleg Nesterov kfree(wq); 31343af24433SOleg Nesterov } 31353af24433SOleg Nesterov EXPORT_SYMBOL_GPL(destroy_workqueue); 31363af24433SOleg Nesterov 3137dcd989cbSTejun Heo /** 3138dcd989cbSTejun Heo * workqueue_set_max_active - adjust max_active of a workqueue 3139dcd989cbSTejun Heo * @wq: target workqueue 3140dcd989cbSTejun Heo * @max_active: new max_active value. 3141dcd989cbSTejun Heo * 3142dcd989cbSTejun Heo * Set max_active of @wq to @max_active. 3143dcd989cbSTejun Heo * 3144dcd989cbSTejun Heo * CONTEXT: 3145dcd989cbSTejun Heo * Don't call from IRQ context. 3146dcd989cbSTejun Heo */ 3147dcd989cbSTejun Heo void workqueue_set_max_active(struct workqueue_struct *wq, int max_active) 3148dcd989cbSTejun Heo { 3149dcd989cbSTejun Heo unsigned int cpu; 3150dcd989cbSTejun Heo 3151f3421797STejun Heo max_active = wq_clamp_max_active(max_active, wq->flags, wq->name); 3152dcd989cbSTejun Heo 3153dcd989cbSTejun Heo spin_lock(&workqueue_lock); 3154dcd989cbSTejun Heo 3155dcd989cbSTejun Heo wq->saved_max_active = max_active; 3156dcd989cbSTejun Heo 3157f3421797STejun Heo for_each_cwq_cpu(cpu, wq) { 3158dcd989cbSTejun Heo struct global_cwq *gcwq = get_gcwq(cpu); 3159dcd989cbSTejun Heo 3160dcd989cbSTejun Heo spin_lock_irq(&gcwq->lock); 3161dcd989cbSTejun Heo 316258a69cb4STejun Heo if (!(wq->flags & WQ_FREEZABLE) || 3163dcd989cbSTejun Heo !(gcwq->flags & GCWQ_FREEZING)) 3164dcd989cbSTejun Heo get_cwq(gcwq->cpu, wq)->max_active = max_active; 3165dcd989cbSTejun Heo 3166dcd989cbSTejun Heo spin_unlock_irq(&gcwq->lock); 3167dcd989cbSTejun Heo } 3168dcd989cbSTejun Heo 3169dcd989cbSTejun Heo spin_unlock(&workqueue_lock); 3170dcd989cbSTejun Heo } 3171dcd989cbSTejun Heo EXPORT_SYMBOL_GPL(workqueue_set_max_active); 3172dcd989cbSTejun Heo 3173dcd989cbSTejun Heo /** 3174dcd989cbSTejun Heo * workqueue_congested - test whether a workqueue is congested 3175dcd989cbSTejun Heo * @cpu: CPU in question 3176dcd989cbSTejun Heo * @wq: target workqueue 3177dcd989cbSTejun Heo * 3178dcd989cbSTejun Heo * Test whether @wq's cpu workqueue for @cpu is congested. There is 3179dcd989cbSTejun Heo * no synchronization around this function and the test result is 3180dcd989cbSTejun Heo * unreliable and only useful as advisory hints or for debugging. 3181dcd989cbSTejun Heo * 3182dcd989cbSTejun Heo * RETURNS: 3183dcd989cbSTejun Heo * %true if congested, %false otherwise. 3184dcd989cbSTejun Heo */ 3185dcd989cbSTejun Heo bool workqueue_congested(unsigned int cpu, struct workqueue_struct *wq) 3186dcd989cbSTejun Heo { 3187dcd989cbSTejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 3188dcd989cbSTejun Heo 3189dcd989cbSTejun Heo return !list_empty(&cwq->delayed_works); 3190dcd989cbSTejun Heo } 3191dcd989cbSTejun Heo EXPORT_SYMBOL_GPL(workqueue_congested); 3192dcd989cbSTejun Heo 3193dcd989cbSTejun Heo /** 3194dcd989cbSTejun Heo * work_cpu - return the last known associated cpu for @work 3195dcd989cbSTejun Heo * @work: the work of interest 3196dcd989cbSTejun Heo * 3197dcd989cbSTejun Heo * RETURNS: 3198bdbc5dd7STejun Heo * CPU number if @work was ever queued. WORK_CPU_NONE otherwise. 3199dcd989cbSTejun Heo */ 3200dcd989cbSTejun Heo unsigned int work_cpu(struct work_struct *work) 3201dcd989cbSTejun Heo { 3202dcd989cbSTejun Heo struct global_cwq *gcwq = get_work_gcwq(work); 3203dcd989cbSTejun Heo 3204bdbc5dd7STejun Heo return gcwq ? gcwq->cpu : WORK_CPU_NONE; 3205dcd989cbSTejun Heo } 3206dcd989cbSTejun Heo EXPORT_SYMBOL_GPL(work_cpu); 3207dcd989cbSTejun Heo 3208dcd989cbSTejun Heo /** 3209dcd989cbSTejun Heo * work_busy - test whether a work is currently pending or running 3210dcd989cbSTejun Heo * @work: the work to be tested 3211dcd989cbSTejun Heo * 3212dcd989cbSTejun Heo * Test whether @work is currently pending or running. There is no 3213dcd989cbSTejun Heo * synchronization around this function and the test result is 3214dcd989cbSTejun Heo * unreliable and only useful as advisory hints or for debugging. 3215dcd989cbSTejun Heo * Especially for reentrant wqs, the pending state might hide the 3216dcd989cbSTejun Heo * running state. 3217dcd989cbSTejun Heo * 3218dcd989cbSTejun Heo * RETURNS: 3219dcd989cbSTejun Heo * OR'd bitmask of WORK_BUSY_* bits. 3220dcd989cbSTejun Heo */ 3221dcd989cbSTejun Heo unsigned int work_busy(struct work_struct *work) 3222dcd989cbSTejun Heo { 3223dcd989cbSTejun Heo struct global_cwq *gcwq = get_work_gcwq(work); 3224dcd989cbSTejun Heo unsigned long flags; 3225dcd989cbSTejun Heo unsigned int ret = 0; 3226dcd989cbSTejun Heo 3227dcd989cbSTejun Heo if (!gcwq) 3228dcd989cbSTejun Heo return false; 3229dcd989cbSTejun Heo 3230dcd989cbSTejun Heo spin_lock_irqsave(&gcwq->lock, flags); 3231dcd989cbSTejun Heo 3232dcd989cbSTejun Heo if (work_pending(work)) 3233dcd989cbSTejun Heo ret |= WORK_BUSY_PENDING; 3234dcd989cbSTejun Heo if (find_worker_executing_work(gcwq, work)) 3235dcd989cbSTejun Heo ret |= WORK_BUSY_RUNNING; 3236dcd989cbSTejun Heo 3237dcd989cbSTejun Heo spin_unlock_irqrestore(&gcwq->lock, flags); 3238dcd989cbSTejun Heo 3239dcd989cbSTejun Heo return ret; 3240dcd989cbSTejun Heo } 3241dcd989cbSTejun Heo EXPORT_SYMBOL_GPL(work_busy); 3242dcd989cbSTejun Heo 3243db7bccf4STejun Heo /* 3244db7bccf4STejun Heo * CPU hotplug. 3245db7bccf4STejun Heo * 3246e22bee78STejun Heo * There are two challenges in supporting CPU hotplug. Firstly, there 3247e22bee78STejun Heo * are a lot of assumptions on strong associations among work, cwq and 3248e22bee78STejun Heo * gcwq which make migrating pending and scheduled works very 3249e22bee78STejun Heo * difficult to implement without impacting hot paths. Secondly, 3250e22bee78STejun Heo * gcwqs serve mix of short, long and very long running works making 3251e22bee78STejun Heo * blocked draining impractical. 3252e22bee78STejun Heo * 3253e22bee78STejun Heo * This is solved by allowing a gcwq to be detached from CPU, running 3254e22bee78STejun Heo * it with unbound (rogue) workers and allowing it to be reattached 3255e22bee78STejun Heo * later if the cpu comes back online. A separate thread is created 3256e22bee78STejun Heo * to govern a gcwq in such state and is called the trustee of the 3257e22bee78STejun Heo * gcwq. 3258db7bccf4STejun Heo * 3259db7bccf4STejun Heo * Trustee states and their descriptions. 3260db7bccf4STejun Heo * 3261db7bccf4STejun Heo * START Command state used on startup. On CPU_DOWN_PREPARE, a 3262db7bccf4STejun Heo * new trustee is started with this state. 3263db7bccf4STejun Heo * 3264db7bccf4STejun Heo * IN_CHARGE Once started, trustee will enter this state after 3265e22bee78STejun Heo * assuming the manager role and making all existing 3266e22bee78STejun Heo * workers rogue. DOWN_PREPARE waits for trustee to 3267e22bee78STejun Heo * enter this state. After reaching IN_CHARGE, trustee 3268e22bee78STejun Heo * tries to execute the pending worklist until it's empty 3269e22bee78STejun Heo * and the state is set to BUTCHER, or the state is set 3270e22bee78STejun Heo * to RELEASE. 3271db7bccf4STejun Heo * 3272db7bccf4STejun Heo * BUTCHER Command state which is set by the cpu callback after 3273db7bccf4STejun Heo * the cpu has went down. Once this state is set trustee 3274db7bccf4STejun Heo * knows that there will be no new works on the worklist 3275db7bccf4STejun Heo * and once the worklist is empty it can proceed to 3276db7bccf4STejun Heo * killing idle workers. 3277db7bccf4STejun Heo * 3278db7bccf4STejun Heo * RELEASE Command state which is set by the cpu callback if the 3279db7bccf4STejun Heo * cpu down has been canceled or it has come online 3280db7bccf4STejun Heo * again. After recognizing this state, trustee stops 3281e22bee78STejun Heo * trying to drain or butcher and clears ROGUE, rebinds 3282e22bee78STejun Heo * all remaining workers back to the cpu and releases 3283e22bee78STejun Heo * manager role. 3284db7bccf4STejun Heo * 3285db7bccf4STejun Heo * DONE Trustee will enter this state after BUTCHER or RELEASE 3286db7bccf4STejun Heo * is complete. 3287db7bccf4STejun Heo * 3288db7bccf4STejun Heo * trustee CPU draining 3289db7bccf4STejun Heo * took over down complete 3290db7bccf4STejun Heo * START -----------> IN_CHARGE -----------> BUTCHER -----------> DONE 3291db7bccf4STejun Heo * | | ^ 3292db7bccf4STejun Heo * | CPU is back online v return workers | 3293db7bccf4STejun Heo * ----------------> RELEASE -------------- 3294db7bccf4STejun Heo */ 3295db7bccf4STejun Heo 3296db7bccf4STejun Heo /** 3297db7bccf4STejun Heo * trustee_wait_event_timeout - timed event wait for trustee 3298db7bccf4STejun Heo * @cond: condition to wait for 3299db7bccf4STejun Heo * @timeout: timeout in jiffies 3300db7bccf4STejun Heo * 3301db7bccf4STejun Heo * wait_event_timeout() for trustee to use. Handles locking and 3302db7bccf4STejun Heo * checks for RELEASE request. 3303db7bccf4STejun Heo * 3304db7bccf4STejun Heo * CONTEXT: 3305db7bccf4STejun Heo * spin_lock_irq(gcwq->lock) which may be released and regrabbed 3306db7bccf4STejun Heo * multiple times. To be used by trustee. 3307db7bccf4STejun Heo * 3308db7bccf4STejun Heo * RETURNS: 3309db7bccf4STejun Heo * Positive indicating left time if @cond is satisfied, 0 if timed 3310db7bccf4STejun Heo * out, -1 if canceled. 3311db7bccf4STejun Heo */ 3312db7bccf4STejun Heo #define trustee_wait_event_timeout(cond, timeout) ({ \ 3313db7bccf4STejun Heo long __ret = (timeout); \ 3314db7bccf4STejun Heo while (!((cond) || (gcwq->trustee_state == TRUSTEE_RELEASE)) && \ 3315db7bccf4STejun Heo __ret) { \ 3316db7bccf4STejun Heo spin_unlock_irq(&gcwq->lock); \ 3317db7bccf4STejun Heo __wait_event_timeout(gcwq->trustee_wait, (cond) || \ 3318db7bccf4STejun Heo (gcwq->trustee_state == TRUSTEE_RELEASE), \ 3319db7bccf4STejun Heo __ret); \ 3320db7bccf4STejun Heo spin_lock_irq(&gcwq->lock); \ 3321db7bccf4STejun Heo } \ 3322db7bccf4STejun Heo gcwq->trustee_state == TRUSTEE_RELEASE ? -1 : (__ret); \ 3323db7bccf4STejun Heo }) 3324db7bccf4STejun Heo 3325db7bccf4STejun Heo /** 3326db7bccf4STejun Heo * trustee_wait_event - event wait for trustee 3327db7bccf4STejun Heo * @cond: condition to wait for 3328db7bccf4STejun Heo * 3329db7bccf4STejun Heo * wait_event() for trustee to use. Automatically handles locking and 3330db7bccf4STejun Heo * checks for CANCEL request. 3331db7bccf4STejun Heo * 3332db7bccf4STejun Heo * CONTEXT: 3333db7bccf4STejun Heo * spin_lock_irq(gcwq->lock) which may be released and regrabbed 3334db7bccf4STejun Heo * multiple times. To be used by trustee. 3335db7bccf4STejun Heo * 3336db7bccf4STejun Heo * RETURNS: 3337db7bccf4STejun Heo * 0 if @cond is satisfied, -1 if canceled. 3338db7bccf4STejun Heo */ 3339db7bccf4STejun Heo #define trustee_wait_event(cond) ({ \ 3340db7bccf4STejun Heo long __ret1; \ 3341db7bccf4STejun Heo __ret1 = trustee_wait_event_timeout(cond, MAX_SCHEDULE_TIMEOUT);\ 3342db7bccf4STejun Heo __ret1 < 0 ? -1 : 0; \ 3343db7bccf4STejun Heo }) 3344db7bccf4STejun Heo 3345db7bccf4STejun Heo static int __cpuinit trustee_thread(void *__gcwq) 3346db7bccf4STejun Heo { 3347db7bccf4STejun Heo struct global_cwq *gcwq = __gcwq; 3348db7bccf4STejun Heo struct worker *worker; 3349e22bee78STejun Heo struct work_struct *work; 3350db7bccf4STejun Heo struct hlist_node *pos; 3351e22bee78STejun Heo long rc; 3352db7bccf4STejun Heo int i; 3353db7bccf4STejun Heo 3354db7bccf4STejun Heo BUG_ON(gcwq->cpu != smp_processor_id()); 3355db7bccf4STejun Heo 3356db7bccf4STejun Heo spin_lock_irq(&gcwq->lock); 3357db7bccf4STejun Heo /* 3358e22bee78STejun Heo * Claim the manager position and make all workers rogue. 3359e22bee78STejun Heo * Trustee must be bound to the target cpu and can't be 3360e22bee78STejun Heo * cancelled. 3361db7bccf4STejun Heo */ 3362db7bccf4STejun Heo BUG_ON(gcwq->cpu != smp_processor_id()); 3363e22bee78STejun Heo rc = trustee_wait_event(!(gcwq->flags & GCWQ_MANAGING_WORKERS)); 3364e22bee78STejun Heo BUG_ON(rc < 0); 3365e22bee78STejun Heo 3366e22bee78STejun Heo gcwq->flags |= GCWQ_MANAGING_WORKERS; 3367db7bccf4STejun Heo 3368bd7bdd43STejun Heo list_for_each_entry(worker, &gcwq->pool.idle_list, entry) 3369cb444766STejun Heo worker->flags |= WORKER_ROGUE; 3370db7bccf4STejun Heo 3371db7bccf4STejun Heo for_each_busy_worker(worker, i, pos, gcwq) 3372cb444766STejun Heo worker->flags |= WORKER_ROGUE; 3373db7bccf4STejun Heo 3374db7bccf4STejun Heo /* 3375e22bee78STejun Heo * Call schedule() so that we cross rq->lock and thus can 3376e22bee78STejun Heo * guarantee sched callbacks see the rogue flag. This is 3377e22bee78STejun Heo * necessary as scheduler callbacks may be invoked from other 3378e22bee78STejun Heo * cpus. 3379e22bee78STejun Heo */ 3380e22bee78STejun Heo spin_unlock_irq(&gcwq->lock); 3381e22bee78STejun Heo schedule(); 3382e22bee78STejun Heo spin_lock_irq(&gcwq->lock); 3383e22bee78STejun Heo 3384e22bee78STejun Heo /* 3385cb444766STejun Heo * Sched callbacks are disabled now. Zap nr_running. After 3386cb444766STejun Heo * this, nr_running stays zero and need_more_worker() and 3387cb444766STejun Heo * keep_working() are always true as long as the worklist is 3388cb444766STejun Heo * not empty. 3389e22bee78STejun Heo */ 339063d95a91STejun Heo atomic_set(get_pool_nr_running(&gcwq->pool), 0); 3391e22bee78STejun Heo 3392e22bee78STejun Heo spin_unlock_irq(&gcwq->lock); 3393bd7bdd43STejun Heo del_timer_sync(&gcwq->pool.idle_timer); 3394e22bee78STejun Heo spin_lock_irq(&gcwq->lock); 3395e22bee78STejun Heo 3396e22bee78STejun Heo /* 3397db7bccf4STejun Heo * We're now in charge. Notify and proceed to drain. We need 3398db7bccf4STejun Heo * to keep the gcwq running during the whole CPU down 3399db7bccf4STejun Heo * procedure as other cpu hotunplug callbacks may need to 3400db7bccf4STejun Heo * flush currently running tasks. 3401db7bccf4STejun Heo */ 3402db7bccf4STejun Heo gcwq->trustee_state = TRUSTEE_IN_CHARGE; 3403db7bccf4STejun Heo wake_up_all(&gcwq->trustee_wait); 3404db7bccf4STejun Heo 3405db7bccf4STejun Heo /* 3406db7bccf4STejun Heo * The original cpu is in the process of dying and may go away 3407db7bccf4STejun Heo * anytime now. When that happens, we and all workers would 3408e22bee78STejun Heo * be migrated to other cpus. Try draining any left work. We 3409e22bee78STejun Heo * want to get it over with ASAP - spam rescuers, wake up as 3410e22bee78STejun Heo * many idlers as necessary and create new ones till the 3411e22bee78STejun Heo * worklist is empty. Note that if the gcwq is frozen, there 341258a69cb4STejun Heo * may be frozen works in freezable cwqs. Don't declare 3413e22bee78STejun Heo * completion while frozen. 3414db7bccf4STejun Heo */ 3415bd7bdd43STejun Heo while (gcwq->pool.nr_workers != gcwq->pool.nr_idle || 3416db7bccf4STejun Heo gcwq->flags & GCWQ_FREEZING || 3417db7bccf4STejun Heo gcwq->trustee_state == TRUSTEE_IN_CHARGE) { 3418e22bee78STejun Heo int nr_works = 0; 3419e22bee78STejun Heo 3420bd7bdd43STejun Heo list_for_each_entry(work, &gcwq->pool.worklist, entry) { 3421e22bee78STejun Heo send_mayday(work); 3422e22bee78STejun Heo nr_works++; 3423e22bee78STejun Heo } 3424e22bee78STejun Heo 3425bd7bdd43STejun Heo list_for_each_entry(worker, &gcwq->pool.idle_list, entry) { 3426e22bee78STejun Heo if (!nr_works--) 3427e22bee78STejun Heo break; 3428e22bee78STejun Heo wake_up_process(worker->task); 3429e22bee78STejun Heo } 3430e22bee78STejun Heo 343163d95a91STejun Heo if (need_to_create_worker(&gcwq->pool)) { 3432e22bee78STejun Heo spin_unlock_irq(&gcwq->lock); 343363d95a91STejun Heo worker = create_worker(&gcwq->pool, false); 3434e22bee78STejun Heo spin_lock_irq(&gcwq->lock); 3435e22bee78STejun Heo if (worker) { 3436cb444766STejun Heo worker->flags |= WORKER_ROGUE; 3437e22bee78STejun Heo start_worker(worker); 3438e22bee78STejun Heo } 3439e22bee78STejun Heo } 3440e22bee78STejun Heo 3441db7bccf4STejun Heo /* give a breather */ 3442db7bccf4STejun Heo if (trustee_wait_event_timeout(false, TRUSTEE_COOLDOWN) < 0) 3443db7bccf4STejun Heo break; 3444db7bccf4STejun Heo } 3445db7bccf4STejun Heo 3446e22bee78STejun Heo /* 3447e22bee78STejun Heo * Either all works have been scheduled and cpu is down, or 3448e22bee78STejun Heo * cpu down has already been canceled. Wait for and butcher 3449e22bee78STejun Heo * all workers till we're canceled. 3450e22bee78STejun Heo */ 3451e22bee78STejun Heo do { 3452bd7bdd43STejun Heo rc = trustee_wait_event(!list_empty(&gcwq->pool.idle_list)); 3453bd7bdd43STejun Heo while (!list_empty(&gcwq->pool.idle_list)) 3454bd7bdd43STejun Heo destroy_worker(list_first_entry(&gcwq->pool.idle_list, 3455e22bee78STejun Heo struct worker, entry)); 3456bd7bdd43STejun Heo } while (gcwq->pool.nr_workers && rc >= 0); 3457e22bee78STejun Heo 3458e22bee78STejun Heo /* 3459e22bee78STejun Heo * At this point, either draining has completed and no worker 3460e22bee78STejun Heo * is left, or cpu down has been canceled or the cpu is being 3461e22bee78STejun Heo * brought back up. There shouldn't be any idle one left. 3462e22bee78STejun Heo * Tell the remaining busy ones to rebind once it finishes the 3463e22bee78STejun Heo * currently scheduled works by scheduling the rebind_work. 3464e22bee78STejun Heo */ 3465bd7bdd43STejun Heo WARN_ON(!list_empty(&gcwq->pool.idle_list)); 3466e22bee78STejun Heo 3467e22bee78STejun Heo for_each_busy_worker(worker, i, pos, gcwq) { 3468e22bee78STejun Heo struct work_struct *rebind_work = &worker->rebind_work; 3469e22bee78STejun Heo 3470e22bee78STejun Heo /* 3471e22bee78STejun Heo * Rebind_work may race with future cpu hotplug 3472e22bee78STejun Heo * operations. Use a separate flag to mark that 3473e22bee78STejun Heo * rebinding is scheduled. 3474e22bee78STejun Heo */ 3475cb444766STejun Heo worker->flags |= WORKER_REBIND; 3476cb444766STejun Heo worker->flags &= ~WORKER_ROGUE; 3477e22bee78STejun Heo 3478e22bee78STejun Heo /* queue rebind_work, wq doesn't matter, use the default one */ 3479e22bee78STejun Heo if (test_and_set_bit(WORK_STRUCT_PENDING_BIT, 3480e22bee78STejun Heo work_data_bits(rebind_work))) 3481e22bee78STejun Heo continue; 3482e22bee78STejun Heo 3483e22bee78STejun Heo debug_work_activate(rebind_work); 3484d320c038STejun Heo insert_work(get_cwq(gcwq->cpu, system_wq), rebind_work, 3485e22bee78STejun Heo worker->scheduled.next, 3486e22bee78STejun Heo work_color_to_flags(WORK_NO_COLOR)); 3487e22bee78STejun Heo } 3488e22bee78STejun Heo 3489e22bee78STejun Heo /* relinquish manager role */ 3490e22bee78STejun Heo gcwq->flags &= ~GCWQ_MANAGING_WORKERS; 3491e22bee78STejun Heo 3492db7bccf4STejun Heo /* notify completion */ 3493db7bccf4STejun Heo gcwq->trustee = NULL; 3494db7bccf4STejun Heo gcwq->trustee_state = TRUSTEE_DONE; 3495db7bccf4STejun Heo wake_up_all(&gcwq->trustee_wait); 3496db7bccf4STejun Heo spin_unlock_irq(&gcwq->lock); 3497db7bccf4STejun Heo return 0; 3498db7bccf4STejun Heo } 3499db7bccf4STejun Heo 3500db7bccf4STejun Heo /** 3501db7bccf4STejun Heo * wait_trustee_state - wait for trustee to enter the specified state 3502db7bccf4STejun Heo * @gcwq: gcwq the trustee of interest belongs to 3503db7bccf4STejun Heo * @state: target state to wait for 3504db7bccf4STejun Heo * 3505db7bccf4STejun Heo * Wait for the trustee to reach @state. DONE is already matched. 3506db7bccf4STejun Heo * 3507db7bccf4STejun Heo * CONTEXT: 3508db7bccf4STejun Heo * spin_lock_irq(gcwq->lock) which may be released and regrabbed 3509db7bccf4STejun Heo * multiple times. To be used by cpu_callback. 3510db7bccf4STejun Heo */ 3511db7bccf4STejun Heo static void __cpuinit wait_trustee_state(struct global_cwq *gcwq, int state) 351206bd6ebfSNamhyung Kim __releases(&gcwq->lock) 351306bd6ebfSNamhyung Kim __acquires(&gcwq->lock) 3514db7bccf4STejun Heo { 3515db7bccf4STejun Heo if (!(gcwq->trustee_state == state || 3516db7bccf4STejun Heo gcwq->trustee_state == TRUSTEE_DONE)) { 3517db7bccf4STejun Heo spin_unlock_irq(&gcwq->lock); 3518db7bccf4STejun Heo __wait_event(gcwq->trustee_wait, 3519db7bccf4STejun Heo gcwq->trustee_state == state || 3520db7bccf4STejun Heo gcwq->trustee_state == TRUSTEE_DONE); 3521db7bccf4STejun Heo spin_lock_irq(&gcwq->lock); 3522db7bccf4STejun Heo } 3523db7bccf4STejun Heo } 3524db7bccf4STejun Heo 35259c7b216dSChandra Seetharaman static int __devinit workqueue_cpu_callback(struct notifier_block *nfb, 35261da177e4SLinus Torvalds unsigned long action, 35271da177e4SLinus Torvalds void *hcpu) 35281da177e4SLinus Torvalds { 35293af24433SOleg Nesterov unsigned int cpu = (unsigned long)hcpu; 3530db7bccf4STejun Heo struct global_cwq *gcwq = get_gcwq(cpu); 3531db7bccf4STejun Heo struct task_struct *new_trustee = NULL; 3532e22bee78STejun Heo struct worker *uninitialized_var(new_worker); 3533db7bccf4STejun Heo unsigned long flags; 35341da177e4SLinus Torvalds 35358bb78442SRafael J. Wysocki action &= ~CPU_TASKS_FROZEN; 35368bb78442SRafael J. Wysocki 35371da177e4SLinus Torvalds switch (action) { 3538db7bccf4STejun Heo case CPU_DOWN_PREPARE: 3539db7bccf4STejun Heo new_trustee = kthread_create(trustee_thread, gcwq, 3540db7bccf4STejun Heo "workqueue_trustee/%d\n", cpu); 3541db7bccf4STejun Heo if (IS_ERR(new_trustee)) 3542db7bccf4STejun Heo return notifier_from_errno(PTR_ERR(new_trustee)); 3543db7bccf4STejun Heo kthread_bind(new_trustee, cpu); 3544e22bee78STejun Heo /* fall through */ 35453af24433SOleg Nesterov case CPU_UP_PREPARE: 3546bd7bdd43STejun Heo BUG_ON(gcwq->pool.first_idle); 354763d95a91STejun Heo new_worker = create_worker(&gcwq->pool, false); 3548e22bee78STejun Heo if (!new_worker) { 3549e22bee78STejun Heo if (new_trustee) 3550e22bee78STejun Heo kthread_stop(new_trustee); 3551e22bee78STejun Heo return NOTIFY_BAD; 35523af24433SOleg Nesterov } 3553db7bccf4STejun Heo } 35541537663fSTejun Heo 3555db7bccf4STejun Heo /* some are called w/ irq disabled, don't disturb irq status */ 3556db7bccf4STejun Heo spin_lock_irqsave(&gcwq->lock, flags); 35573af24433SOleg Nesterov 35583af24433SOleg Nesterov switch (action) { 3559db7bccf4STejun Heo case CPU_DOWN_PREPARE: 3560db7bccf4STejun Heo /* initialize trustee and tell it to acquire the gcwq */ 3561db7bccf4STejun Heo BUG_ON(gcwq->trustee || gcwq->trustee_state != TRUSTEE_DONE); 3562db7bccf4STejun Heo gcwq->trustee = new_trustee; 3563db7bccf4STejun Heo gcwq->trustee_state = TRUSTEE_START; 3564db7bccf4STejun Heo wake_up_process(gcwq->trustee); 3565db7bccf4STejun Heo wait_trustee_state(gcwq, TRUSTEE_IN_CHARGE); 3566e22bee78STejun Heo /* fall through */ 35673af24433SOleg Nesterov case CPU_UP_PREPARE: 3568bd7bdd43STejun Heo BUG_ON(gcwq->pool.first_idle); 3569bd7bdd43STejun Heo gcwq->pool.first_idle = new_worker; 35701da177e4SLinus Torvalds break; 35711da177e4SLinus Torvalds 3572e22bee78STejun Heo case CPU_DYING: 3573e22bee78STejun Heo /* 3574e22bee78STejun Heo * Before this, the trustee and all workers except for 3575e22bee78STejun Heo * the ones which are still executing works from 3576e22bee78STejun Heo * before the last CPU down must be on the cpu. After 3577e22bee78STejun Heo * this, they'll all be diasporas. 3578e22bee78STejun Heo */ 3579e22bee78STejun Heo gcwq->flags |= GCWQ_DISASSOCIATED; 3580db7bccf4STejun Heo break; 3581db7bccf4STejun Heo 35823da1c84cSOleg Nesterov case CPU_POST_DEAD: 3583db7bccf4STejun Heo gcwq->trustee_state = TRUSTEE_BUTCHER; 3584e22bee78STejun Heo /* fall through */ 3585e22bee78STejun Heo case CPU_UP_CANCELED: 3586bd7bdd43STejun Heo destroy_worker(gcwq->pool.first_idle); 3587bd7bdd43STejun Heo gcwq->pool.first_idle = NULL; 3588db7bccf4STejun Heo break; 3589db7bccf4STejun Heo 3590db7bccf4STejun Heo case CPU_DOWN_FAILED: 35911da177e4SLinus Torvalds case CPU_ONLINE: 3592e22bee78STejun Heo gcwq->flags &= ~GCWQ_DISASSOCIATED; 3593db7bccf4STejun Heo if (gcwq->trustee_state != TRUSTEE_DONE) { 3594db7bccf4STejun Heo gcwq->trustee_state = TRUSTEE_RELEASE; 3595db7bccf4STejun Heo wake_up_process(gcwq->trustee); 3596db7bccf4STejun Heo wait_trustee_state(gcwq, TRUSTEE_DONE); 3597db7bccf4STejun Heo } 35981da177e4SLinus Torvalds 3599e22bee78STejun Heo /* 3600e22bee78STejun Heo * Trustee is done and there might be no worker left. 3601e22bee78STejun Heo * Put the first_idle in and request a real manager to 3602e22bee78STejun Heo * take a look. 3603e22bee78STejun Heo */ 3604e22bee78STejun Heo spin_unlock_irq(&gcwq->lock); 3605bd7bdd43STejun Heo kthread_bind(gcwq->pool.first_idle->task, cpu); 3606e22bee78STejun Heo spin_lock_irq(&gcwq->lock); 3607e22bee78STejun Heo gcwq->flags |= GCWQ_MANAGE_WORKERS; 3608bd7bdd43STejun Heo start_worker(gcwq->pool.first_idle); 3609bd7bdd43STejun Heo gcwq->pool.first_idle = NULL; 36101da177e4SLinus Torvalds break; 36111da177e4SLinus Torvalds } 36121da177e4SLinus Torvalds 3613db7bccf4STejun Heo spin_unlock_irqrestore(&gcwq->lock, flags); 361400dfcaf7SOleg Nesterov 36151537663fSTejun Heo return notifier_from_errno(0); 36161da177e4SLinus Torvalds } 36171da177e4SLinus Torvalds 36182d3854a3SRusty Russell #ifdef CONFIG_SMP 36198ccad40dSRusty Russell 36202d3854a3SRusty Russell struct work_for_cpu { 36216b44003eSAndrew Morton struct completion completion; 36222d3854a3SRusty Russell long (*fn)(void *); 36232d3854a3SRusty Russell void *arg; 36242d3854a3SRusty Russell long ret; 36252d3854a3SRusty Russell }; 36262d3854a3SRusty Russell 36276b44003eSAndrew Morton static int do_work_for_cpu(void *_wfc) 36282d3854a3SRusty Russell { 36296b44003eSAndrew Morton struct work_for_cpu *wfc = _wfc; 36302d3854a3SRusty Russell wfc->ret = wfc->fn(wfc->arg); 36316b44003eSAndrew Morton complete(&wfc->completion); 36326b44003eSAndrew Morton return 0; 36332d3854a3SRusty Russell } 36342d3854a3SRusty Russell 36352d3854a3SRusty Russell /** 36362d3854a3SRusty Russell * work_on_cpu - run a function in user context on a particular cpu 36372d3854a3SRusty Russell * @cpu: the cpu to run on 36382d3854a3SRusty Russell * @fn: the function to run 36392d3854a3SRusty Russell * @arg: the function arg 36402d3854a3SRusty Russell * 364131ad9081SRusty Russell * This will return the value @fn returns. 364231ad9081SRusty Russell * It is up to the caller to ensure that the cpu doesn't go offline. 36436b44003eSAndrew Morton * The caller must not hold any locks which would prevent @fn from completing. 36442d3854a3SRusty Russell */ 36452d3854a3SRusty Russell long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg) 36462d3854a3SRusty Russell { 36476b44003eSAndrew Morton struct task_struct *sub_thread; 36486b44003eSAndrew Morton struct work_for_cpu wfc = { 36496b44003eSAndrew Morton .completion = COMPLETION_INITIALIZER_ONSTACK(wfc.completion), 36506b44003eSAndrew Morton .fn = fn, 36516b44003eSAndrew Morton .arg = arg, 36526b44003eSAndrew Morton }; 36532d3854a3SRusty Russell 36546b44003eSAndrew Morton sub_thread = kthread_create(do_work_for_cpu, &wfc, "work_for_cpu"); 36556b44003eSAndrew Morton if (IS_ERR(sub_thread)) 36566b44003eSAndrew Morton return PTR_ERR(sub_thread); 36576b44003eSAndrew Morton kthread_bind(sub_thread, cpu); 36586b44003eSAndrew Morton wake_up_process(sub_thread); 36596b44003eSAndrew Morton wait_for_completion(&wfc.completion); 36602d3854a3SRusty Russell return wfc.ret; 36612d3854a3SRusty Russell } 36622d3854a3SRusty Russell EXPORT_SYMBOL_GPL(work_on_cpu); 36632d3854a3SRusty Russell #endif /* CONFIG_SMP */ 36642d3854a3SRusty Russell 3665a0a1a5fdSTejun Heo #ifdef CONFIG_FREEZER 3666e7577c50SRusty Russell 3667a0a1a5fdSTejun Heo /** 3668a0a1a5fdSTejun Heo * freeze_workqueues_begin - begin freezing workqueues 3669a0a1a5fdSTejun Heo * 367058a69cb4STejun Heo * Start freezing workqueues. After this function returns, all freezable 367158a69cb4STejun Heo * workqueues will queue new works to their frozen_works list instead of 367258a69cb4STejun Heo * gcwq->worklist. 3673a0a1a5fdSTejun Heo * 3674a0a1a5fdSTejun Heo * CONTEXT: 36758b03ae3cSTejun Heo * Grabs and releases workqueue_lock and gcwq->lock's. 3676a0a1a5fdSTejun Heo */ 3677a0a1a5fdSTejun Heo void freeze_workqueues_begin(void) 3678a0a1a5fdSTejun Heo { 3679a0a1a5fdSTejun Heo unsigned int cpu; 3680a0a1a5fdSTejun Heo 3681a0a1a5fdSTejun Heo spin_lock(&workqueue_lock); 3682a0a1a5fdSTejun Heo 3683a0a1a5fdSTejun Heo BUG_ON(workqueue_freezing); 3684a0a1a5fdSTejun Heo workqueue_freezing = true; 3685a0a1a5fdSTejun Heo 3686f3421797STejun Heo for_each_gcwq_cpu(cpu) { 36878b03ae3cSTejun Heo struct global_cwq *gcwq = get_gcwq(cpu); 3688bdbc5dd7STejun Heo struct workqueue_struct *wq; 36898b03ae3cSTejun Heo 36908b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 36918b03ae3cSTejun Heo 3692db7bccf4STejun Heo BUG_ON(gcwq->flags & GCWQ_FREEZING); 3693db7bccf4STejun Heo gcwq->flags |= GCWQ_FREEZING; 3694db7bccf4STejun Heo 3695a0a1a5fdSTejun Heo list_for_each_entry(wq, &workqueues, list) { 3696a0a1a5fdSTejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 3697a0a1a5fdSTejun Heo 369858a69cb4STejun Heo if (cwq && wq->flags & WQ_FREEZABLE) 3699a0a1a5fdSTejun Heo cwq->max_active = 0; 37001da177e4SLinus Torvalds } 37018b03ae3cSTejun Heo 37028b03ae3cSTejun Heo spin_unlock_irq(&gcwq->lock); 3703a0a1a5fdSTejun Heo } 3704a0a1a5fdSTejun Heo 3705a0a1a5fdSTejun Heo spin_unlock(&workqueue_lock); 3706a0a1a5fdSTejun Heo } 3707a0a1a5fdSTejun Heo 3708a0a1a5fdSTejun Heo /** 370958a69cb4STejun Heo * freeze_workqueues_busy - are freezable workqueues still busy? 3710a0a1a5fdSTejun Heo * 3711a0a1a5fdSTejun Heo * Check whether freezing is complete. This function must be called 3712a0a1a5fdSTejun Heo * between freeze_workqueues_begin() and thaw_workqueues(). 3713a0a1a5fdSTejun Heo * 3714a0a1a5fdSTejun Heo * CONTEXT: 3715a0a1a5fdSTejun Heo * Grabs and releases workqueue_lock. 3716a0a1a5fdSTejun Heo * 3717a0a1a5fdSTejun Heo * RETURNS: 371858a69cb4STejun Heo * %true if some freezable workqueues are still busy. %false if freezing 371958a69cb4STejun Heo * is complete. 3720a0a1a5fdSTejun Heo */ 3721a0a1a5fdSTejun Heo bool freeze_workqueues_busy(void) 3722a0a1a5fdSTejun Heo { 3723a0a1a5fdSTejun Heo unsigned int cpu; 3724a0a1a5fdSTejun Heo bool busy = false; 3725a0a1a5fdSTejun Heo 3726a0a1a5fdSTejun Heo spin_lock(&workqueue_lock); 3727a0a1a5fdSTejun Heo 3728a0a1a5fdSTejun Heo BUG_ON(!workqueue_freezing); 3729a0a1a5fdSTejun Heo 3730f3421797STejun Heo for_each_gcwq_cpu(cpu) { 3731bdbc5dd7STejun Heo struct workqueue_struct *wq; 3732a0a1a5fdSTejun Heo /* 3733a0a1a5fdSTejun Heo * nr_active is monotonically decreasing. It's safe 3734a0a1a5fdSTejun Heo * to peek without lock. 3735a0a1a5fdSTejun Heo */ 3736a0a1a5fdSTejun Heo list_for_each_entry(wq, &workqueues, list) { 3737a0a1a5fdSTejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 3738a0a1a5fdSTejun Heo 373958a69cb4STejun Heo if (!cwq || !(wq->flags & WQ_FREEZABLE)) 3740a0a1a5fdSTejun Heo continue; 3741a0a1a5fdSTejun Heo 3742a0a1a5fdSTejun Heo BUG_ON(cwq->nr_active < 0); 3743a0a1a5fdSTejun Heo if (cwq->nr_active) { 3744a0a1a5fdSTejun Heo busy = true; 3745a0a1a5fdSTejun Heo goto out_unlock; 3746a0a1a5fdSTejun Heo } 3747a0a1a5fdSTejun Heo } 3748a0a1a5fdSTejun Heo } 3749a0a1a5fdSTejun Heo out_unlock: 3750a0a1a5fdSTejun Heo spin_unlock(&workqueue_lock); 3751a0a1a5fdSTejun Heo return busy; 3752a0a1a5fdSTejun Heo } 3753a0a1a5fdSTejun Heo 3754a0a1a5fdSTejun Heo /** 3755a0a1a5fdSTejun Heo * thaw_workqueues - thaw workqueues 3756a0a1a5fdSTejun Heo * 3757a0a1a5fdSTejun Heo * Thaw workqueues. Normal queueing is restored and all collected 37587e11629dSTejun Heo * frozen works are transferred to their respective gcwq worklists. 3759a0a1a5fdSTejun Heo * 3760a0a1a5fdSTejun Heo * CONTEXT: 37618b03ae3cSTejun Heo * Grabs and releases workqueue_lock and gcwq->lock's. 3762a0a1a5fdSTejun Heo */ 3763a0a1a5fdSTejun Heo void thaw_workqueues(void) 3764a0a1a5fdSTejun Heo { 3765a0a1a5fdSTejun Heo unsigned int cpu; 3766a0a1a5fdSTejun Heo 3767a0a1a5fdSTejun Heo spin_lock(&workqueue_lock); 3768a0a1a5fdSTejun Heo 3769a0a1a5fdSTejun Heo if (!workqueue_freezing) 3770a0a1a5fdSTejun Heo goto out_unlock; 3771a0a1a5fdSTejun Heo 3772f3421797STejun Heo for_each_gcwq_cpu(cpu) { 37738b03ae3cSTejun Heo struct global_cwq *gcwq = get_gcwq(cpu); 3774bdbc5dd7STejun Heo struct workqueue_struct *wq; 37758b03ae3cSTejun Heo 37768b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 37778b03ae3cSTejun Heo 3778db7bccf4STejun Heo BUG_ON(!(gcwq->flags & GCWQ_FREEZING)); 3779db7bccf4STejun Heo gcwq->flags &= ~GCWQ_FREEZING; 3780db7bccf4STejun Heo 3781a0a1a5fdSTejun Heo list_for_each_entry(wq, &workqueues, list) { 3782a0a1a5fdSTejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 3783a0a1a5fdSTejun Heo 378458a69cb4STejun Heo if (!cwq || !(wq->flags & WQ_FREEZABLE)) 3785a0a1a5fdSTejun Heo continue; 3786a0a1a5fdSTejun Heo 3787a0a1a5fdSTejun Heo /* restore max_active and repopulate worklist */ 3788a0a1a5fdSTejun Heo cwq->max_active = wq->saved_max_active; 3789a0a1a5fdSTejun Heo 3790a0a1a5fdSTejun Heo while (!list_empty(&cwq->delayed_works) && 3791a0a1a5fdSTejun Heo cwq->nr_active < cwq->max_active) 3792a0a1a5fdSTejun Heo cwq_activate_first_delayed(cwq); 3793a0a1a5fdSTejun Heo } 37948b03ae3cSTejun Heo 379563d95a91STejun Heo wake_up_worker(&gcwq->pool); 3796e22bee78STejun Heo 37978b03ae3cSTejun Heo spin_unlock_irq(&gcwq->lock); 3798a0a1a5fdSTejun Heo } 3799a0a1a5fdSTejun Heo 3800a0a1a5fdSTejun Heo workqueue_freezing = false; 3801a0a1a5fdSTejun Heo out_unlock: 3802a0a1a5fdSTejun Heo spin_unlock(&workqueue_lock); 3803a0a1a5fdSTejun Heo } 3804a0a1a5fdSTejun Heo #endif /* CONFIG_FREEZER */ 3805a0a1a5fdSTejun Heo 38066ee0578bSSuresh Siddha static int __init init_workqueues(void) 38071da177e4SLinus Torvalds { 3808c34056a3STejun Heo unsigned int cpu; 3809c8e55f36STejun Heo int i; 3810c34056a3STejun Heo 3811f6500947STejun Heo cpu_notifier(workqueue_cpu_callback, CPU_PRI_WORKQUEUE); 38128b03ae3cSTejun Heo 38138b03ae3cSTejun Heo /* initialize gcwqs */ 3814f3421797STejun Heo for_each_gcwq_cpu(cpu) { 38158b03ae3cSTejun Heo struct global_cwq *gcwq = get_gcwq(cpu); 38168b03ae3cSTejun Heo 38178b03ae3cSTejun Heo spin_lock_init(&gcwq->lock); 3818bd7bdd43STejun Heo gcwq->pool.gcwq = gcwq; 3819bd7bdd43STejun Heo INIT_LIST_HEAD(&gcwq->pool.worklist); 38208b03ae3cSTejun Heo gcwq->cpu = cpu; 3821f3421797STejun Heo gcwq->flags |= GCWQ_DISASSOCIATED; 38228b03ae3cSTejun Heo 3823bd7bdd43STejun Heo INIT_LIST_HEAD(&gcwq->pool.idle_list); 3824c8e55f36STejun Heo for (i = 0; i < BUSY_WORKER_HASH_SIZE; i++) 3825c8e55f36STejun Heo INIT_HLIST_HEAD(&gcwq->busy_hash[i]); 3826c8e55f36STejun Heo 3827bd7bdd43STejun Heo init_timer_deferrable(&gcwq->pool.idle_timer); 3828bd7bdd43STejun Heo gcwq->pool.idle_timer.function = idle_worker_timeout; 382963d95a91STejun Heo gcwq->pool.idle_timer.data = (unsigned long)&gcwq->pool; 3830e22bee78STejun Heo 3831bd7bdd43STejun Heo setup_timer(&gcwq->pool.mayday_timer, gcwq_mayday_timeout, 383263d95a91STejun Heo (unsigned long)&gcwq->pool); 3833e22bee78STejun Heo 3834bd7bdd43STejun Heo ida_init(&gcwq->pool.worker_ida); 3835db7bccf4STejun Heo 3836db7bccf4STejun Heo gcwq->trustee_state = TRUSTEE_DONE; 3837db7bccf4STejun Heo init_waitqueue_head(&gcwq->trustee_wait); 38388b03ae3cSTejun Heo } 38398b03ae3cSTejun Heo 3840e22bee78STejun Heo /* create the initial worker */ 3841f3421797STejun Heo for_each_online_gcwq_cpu(cpu) { 3842e22bee78STejun Heo struct global_cwq *gcwq = get_gcwq(cpu); 3843e22bee78STejun Heo struct worker *worker; 3844e22bee78STejun Heo 3845477a3c33STejun Heo if (cpu != WORK_CPU_UNBOUND) 3846477a3c33STejun Heo gcwq->flags &= ~GCWQ_DISASSOCIATED; 384763d95a91STejun Heo worker = create_worker(&gcwq->pool, true); 3848e22bee78STejun Heo BUG_ON(!worker); 3849e22bee78STejun Heo spin_lock_irq(&gcwq->lock); 3850e22bee78STejun Heo start_worker(worker); 3851e22bee78STejun Heo spin_unlock_irq(&gcwq->lock); 3852e22bee78STejun Heo } 3853e22bee78STejun Heo 3854d320c038STejun Heo system_wq = alloc_workqueue("events", 0, 0); 3855d320c038STejun Heo system_long_wq = alloc_workqueue("events_long", 0, 0); 3856d320c038STejun Heo system_nrt_wq = alloc_workqueue("events_nrt", WQ_NON_REENTRANT, 0); 3857f3421797STejun Heo system_unbound_wq = alloc_workqueue("events_unbound", WQ_UNBOUND, 3858f3421797STejun Heo WQ_UNBOUND_MAX_ACTIVE); 385924d51addSTejun Heo system_freezable_wq = alloc_workqueue("events_freezable", 386024d51addSTejun Heo WQ_FREEZABLE, 0); 386162d3c543SAlan Stern system_nrt_freezable_wq = alloc_workqueue("events_nrt_freezable", 386262d3c543SAlan Stern WQ_NON_REENTRANT | WQ_FREEZABLE, 0); 3863e5cba24eSHitoshi Mitake BUG_ON(!system_wq || !system_long_wq || !system_nrt_wq || 386462d3c543SAlan Stern !system_unbound_wq || !system_freezable_wq || 386562d3c543SAlan Stern !system_nrt_freezable_wq); 38666ee0578bSSuresh Siddha return 0; 38671da177e4SLinus Torvalds } 38686ee0578bSSuresh Siddha early_initcall(init_workqueues); 3869