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> 4442f8570fSSasha Levin #include <linux/hashtable.h> 45e22bee78STejun Heo 46ea138446STejun Heo #include "workqueue_internal.h" 471da177e4SLinus Torvalds 48c8e55f36STejun Heo enum { 49bc2ae0f5STejun Heo /* 50bc2ae0f5STejun Heo * global_cwq flags 51bc2ae0f5STejun Heo * 52bc2ae0f5STejun Heo * A bound gcwq is either associated or disassociated with its CPU. 53bc2ae0f5STejun Heo * While associated (!DISASSOCIATED), all workers are bound to the 54bc2ae0f5STejun Heo * CPU and none has %WORKER_UNBOUND set and concurrency management 55bc2ae0f5STejun Heo * is in effect. 56bc2ae0f5STejun Heo * 57bc2ae0f5STejun Heo * While DISASSOCIATED, the cpu may be offline and all workers have 58bc2ae0f5STejun Heo * %WORKER_UNBOUND set and concurrency management disabled, and may 59bc2ae0f5STejun Heo * be executing on any CPU. The gcwq behaves as an unbound one. 60bc2ae0f5STejun Heo * 61bc2ae0f5STejun Heo * Note that DISASSOCIATED can be flipped only while holding 62b2eb83d1SLai Jiangshan * assoc_mutex of all pools on the gcwq to avoid changing binding 63bc2ae0f5STejun Heo * state while create_worker() is in progress. 64bc2ae0f5STejun Heo */ 6511ebea50STejun Heo GCWQ_DISASSOCIATED = 1 << 0, /* cpu can't serve workers */ 6611ebea50STejun Heo GCWQ_FREEZING = 1 << 1, /* freeze in progress */ 6711ebea50STejun Heo 6811ebea50STejun Heo /* pool flags */ 6911ebea50STejun Heo POOL_MANAGE_WORKERS = 1 << 0, /* need to manage workers */ 70552a37e9SLai Jiangshan POOL_MANAGING_WORKERS = 1 << 1, /* managing workers */ 71db7bccf4STejun Heo 72c8e55f36STejun Heo /* worker flags */ 73c8e55f36STejun Heo WORKER_STARTED = 1 << 0, /* started */ 74c8e55f36STejun Heo WORKER_DIE = 1 << 1, /* die die die */ 75c8e55f36STejun Heo WORKER_IDLE = 1 << 2, /* is idle */ 76e22bee78STejun Heo WORKER_PREP = 1 << 3, /* preparing to run works */ 77fb0e7bebSTejun Heo WORKER_CPU_INTENSIVE = 1 << 6, /* cpu intensive */ 78f3421797STejun Heo WORKER_UNBOUND = 1 << 7, /* worker is unbound */ 79e22bee78STejun Heo 805f7dabfdSLai Jiangshan WORKER_NOT_RUNNING = WORKER_PREP | WORKER_UNBOUND | 81403c821dSTejun Heo WORKER_CPU_INTENSIVE, 82db7bccf4STejun Heo 833270476aSTejun Heo NR_WORKER_POOLS = 2, /* # worker pools per gcwq */ 844ce62e9eSTejun Heo 85c8e55f36STejun Heo BUSY_WORKER_HASH_ORDER = 6, /* 64 pointers */ 86db7bccf4STejun Heo 87e22bee78STejun Heo MAX_IDLE_WORKERS_RATIO = 4, /* 1/4 of busy can be idle */ 88e22bee78STejun Heo IDLE_WORKER_TIMEOUT = 300 * HZ, /* keep idle ones for 5 mins */ 89e22bee78STejun Heo 903233cdbdSTejun Heo MAYDAY_INITIAL_TIMEOUT = HZ / 100 >= 2 ? HZ / 100 : 2, 913233cdbdSTejun Heo /* call for help after 10ms 923233cdbdSTejun Heo (min two ticks) */ 93e22bee78STejun Heo MAYDAY_INTERVAL = HZ / 10, /* and then every 100ms */ 94e22bee78STejun Heo CREATE_COOLDOWN = HZ, /* time to breath after fail */ 951da177e4SLinus Torvalds 961da177e4SLinus Torvalds /* 97e22bee78STejun Heo * Rescue workers are used only on emergencies and shared by 98e22bee78STejun Heo * all cpus. Give -20. 99e22bee78STejun Heo */ 100e22bee78STejun Heo RESCUER_NICE_LEVEL = -20, 1013270476aSTejun Heo HIGHPRI_NICE_LEVEL = -20, 102c8e55f36STejun Heo }; 103c8e55f36STejun Heo 1041da177e4SLinus Torvalds /* 1054690c4abSTejun Heo * Structure fields follow one of the following exclusion rules. 1064690c4abSTejun Heo * 107e41e704bSTejun Heo * I: Modifiable by initialization/destruction paths and read-only for 108e41e704bSTejun Heo * everyone else. 1094690c4abSTejun Heo * 110e22bee78STejun Heo * P: Preemption protected. Disabling preemption is enough and should 111e22bee78STejun Heo * only be modified and accessed from the local cpu. 112e22bee78STejun Heo * 1138b03ae3cSTejun Heo * L: gcwq->lock protected. Access with gcwq->lock held. 1144690c4abSTejun Heo * 115e22bee78STejun Heo * X: During normal operation, modification requires gcwq->lock and 116e22bee78STejun Heo * should be done only from local cpu. Either disabling preemption 117e22bee78STejun Heo * on local cpu or grabbing gcwq->lock is enough for read access. 118f3421797STejun Heo * If GCWQ_DISASSOCIATED is set, it's identical to L. 119e22bee78STejun Heo * 12073f53c4aSTejun Heo * F: wq->flush_mutex protected. 12173f53c4aSTejun Heo * 1224690c4abSTejun Heo * W: workqueue_lock protected. 1234690c4abSTejun Heo */ 1244690c4abSTejun Heo 1258b03ae3cSTejun Heo struct global_cwq; 126bd7bdd43STejun Heo struct worker_pool; 127c34056a3STejun Heo 128e22bee78STejun Heo /* 129e22bee78STejun Heo * The poor guys doing the actual heavy lifting. All on-duty workers 130e22bee78STejun Heo * are either serving the manager role, on idle list or on busy hash. 131e22bee78STejun Heo */ 132c34056a3STejun Heo struct worker { 133c8e55f36STejun Heo /* on idle list while idle, on busy hash table while busy */ 134c8e55f36STejun Heo union { 135c8e55f36STejun Heo struct list_head entry; /* L: while idle */ 136c8e55f36STejun Heo struct hlist_node hentry; /* L: while busy */ 137c8e55f36STejun Heo }; 138c8e55f36STejun Heo 139c34056a3STejun Heo struct work_struct *current_work; /* L: work being processed */ 140a2c1c57bSTejun Heo work_func_t current_func; /* L: current_work's fn */ 1418cca0eeaSTejun Heo struct cpu_workqueue_struct *current_cwq; /* L: current_work's cwq */ 142affee4b2STejun Heo struct list_head scheduled; /* L: scheduled works */ 143c34056a3STejun Heo struct task_struct *task; /* I: worker task */ 144bd7bdd43STejun Heo struct worker_pool *pool; /* I: the associated pool */ 145e22bee78STejun Heo /* 64 bytes boundary on 64bit, 32 on 32bit */ 146e22bee78STejun Heo unsigned long last_active; /* L: last active timestamp */ 147e22bee78STejun Heo unsigned int flags; /* X: flags */ 148c34056a3STejun Heo int id; /* I: worker id */ 14925511a47STejun Heo 15025511a47STejun Heo /* for rebinding worker to CPU */ 15125511a47STejun Heo struct work_struct rebind_work; /* L: for busy worker */ 152111c225aSTejun Heo 153111c225aSTejun Heo /* used only by rescuers to point to the target workqueue */ 154111c225aSTejun Heo struct workqueue_struct *rescue_wq; /* I: the workqueue to rescue */ 155c34056a3STejun Heo }; 156c34056a3STejun Heo 157bd7bdd43STejun Heo struct worker_pool { 158bd7bdd43STejun Heo struct global_cwq *gcwq; /* I: the owning gcwq */ 15911ebea50STejun Heo unsigned int flags; /* X: flags */ 160bd7bdd43STejun Heo 161bd7bdd43STejun Heo struct list_head worklist; /* L: list of pending works */ 162bd7bdd43STejun Heo int nr_workers; /* L: total number of workers */ 163ea1abd61SLai Jiangshan 164ea1abd61SLai Jiangshan /* nr_idle includes the ones off idle_list for rebinding */ 165bd7bdd43STejun Heo int nr_idle; /* L: currently idle ones */ 166bd7bdd43STejun Heo 167bd7bdd43STejun Heo struct list_head idle_list; /* X: list of idle workers */ 168bd7bdd43STejun Heo struct timer_list idle_timer; /* L: worker idle timeout */ 169bd7bdd43STejun Heo struct timer_list mayday_timer; /* L: SOS timer for workers */ 170bd7bdd43STejun Heo 171b2eb83d1SLai Jiangshan struct mutex assoc_mutex; /* protect GCWQ_DISASSOCIATED */ 172bd7bdd43STejun Heo struct ida worker_ida; /* L: for worker IDs */ 173bd7bdd43STejun Heo }; 174bd7bdd43STejun Heo 1754690c4abSTejun Heo /* 176e22bee78STejun Heo * Global per-cpu workqueue. There's one and only one for each cpu 177e22bee78STejun Heo * and all works are queued and processed here regardless of their 178e22bee78STejun Heo * target workqueues. 1798b03ae3cSTejun Heo */ 1808b03ae3cSTejun Heo struct global_cwq { 1818b03ae3cSTejun Heo spinlock_t lock; /* the gcwq lock */ 1828b03ae3cSTejun Heo unsigned int cpu; /* I: the associated cpu */ 183db7bccf4STejun Heo unsigned int flags; /* L: GCWQ_* flags */ 184c8e55f36STejun Heo 185bd7bdd43STejun Heo /* workers are chained either in busy_hash or pool idle_list */ 18642f8570fSSasha Levin DECLARE_HASHTABLE(busy_hash, BUSY_WORKER_HASH_ORDER); 187c8e55f36STejun Heo /* L: hash of busy workers */ 188c8e55f36STejun Heo 189330dad5bSJoonsoo Kim struct worker_pool pools[NR_WORKER_POOLS]; 190330dad5bSJoonsoo Kim /* normal and highpri pools */ 1918b03ae3cSTejun Heo } ____cacheline_aligned_in_smp; 1928b03ae3cSTejun Heo 1938b03ae3cSTejun Heo /* 194502ca9d8STejun Heo * The per-CPU workqueue. The lower WORK_STRUCT_FLAG_BITS of 1950f900049STejun Heo * work_struct->data are used for flags and thus cwqs need to be 1960f900049STejun Heo * aligned at two's power of the number of flag bits. 1971da177e4SLinus Torvalds */ 1981da177e4SLinus Torvalds struct cpu_workqueue_struct { 199bd7bdd43STejun Heo struct worker_pool *pool; /* I: the associated pool */ 2004690c4abSTejun Heo struct workqueue_struct *wq; /* I: the owning workqueue */ 20173f53c4aSTejun Heo int work_color; /* L: current color */ 20273f53c4aSTejun Heo int flush_color; /* L: flushing color */ 20373f53c4aSTejun Heo int nr_in_flight[WORK_NR_COLORS]; 20473f53c4aSTejun Heo /* L: nr of in_flight works */ 2051e19ffc6STejun Heo int nr_active; /* L: nr of active works */ 206a0a1a5fdSTejun Heo int max_active; /* L: max active works */ 2071e19ffc6STejun Heo struct list_head delayed_works; /* L: delayed works */ 2080f900049STejun Heo }; 2091da177e4SLinus Torvalds 2101da177e4SLinus Torvalds /* 21173f53c4aSTejun Heo * Structure used to wait for workqueue flush. 21273f53c4aSTejun Heo */ 21373f53c4aSTejun Heo struct wq_flusher { 21473f53c4aSTejun Heo struct list_head list; /* F: list of flushers */ 21573f53c4aSTejun Heo int flush_color; /* F: flush color waiting for */ 21673f53c4aSTejun Heo struct completion done; /* flush completion */ 21773f53c4aSTejun Heo }; 2181da177e4SLinus Torvalds 21973f53c4aSTejun Heo /* 220f2e005aaSTejun Heo * All cpumasks are assumed to be always set on UP and thus can't be 221f2e005aaSTejun Heo * used to determine whether there's something to be done. 222f2e005aaSTejun Heo */ 223f2e005aaSTejun Heo #ifdef CONFIG_SMP 224f2e005aaSTejun Heo typedef cpumask_var_t mayday_mask_t; 225f2e005aaSTejun Heo #define mayday_test_and_set_cpu(cpu, mask) \ 226f2e005aaSTejun Heo cpumask_test_and_set_cpu((cpu), (mask)) 227f2e005aaSTejun Heo #define mayday_clear_cpu(cpu, mask) cpumask_clear_cpu((cpu), (mask)) 228f2e005aaSTejun Heo #define for_each_mayday_cpu(cpu, mask) for_each_cpu((cpu), (mask)) 2299c37547aSTejun Heo #define alloc_mayday_mask(maskp, gfp) zalloc_cpumask_var((maskp), (gfp)) 230f2e005aaSTejun Heo #define free_mayday_mask(mask) free_cpumask_var((mask)) 231f2e005aaSTejun Heo #else 232f2e005aaSTejun Heo typedef unsigned long mayday_mask_t; 233f2e005aaSTejun Heo #define mayday_test_and_set_cpu(cpu, mask) test_and_set_bit(0, &(mask)) 234f2e005aaSTejun Heo #define mayday_clear_cpu(cpu, mask) clear_bit(0, &(mask)) 235f2e005aaSTejun Heo #define for_each_mayday_cpu(cpu, mask) if ((cpu) = 0, (mask)) 236f2e005aaSTejun Heo #define alloc_mayday_mask(maskp, gfp) true 237f2e005aaSTejun Heo #define free_mayday_mask(mask) do { } while (0) 238f2e005aaSTejun Heo #endif 2391da177e4SLinus Torvalds 2401da177e4SLinus Torvalds /* 2411da177e4SLinus Torvalds * The externally visible workqueue abstraction is an array of 2421da177e4SLinus Torvalds * per-CPU workqueues: 2431da177e4SLinus Torvalds */ 2441da177e4SLinus Torvalds struct workqueue_struct { 2459c5a2ba7STejun Heo unsigned int flags; /* W: WQ_* flags */ 246bdbc5dd7STejun Heo union { 247bdbc5dd7STejun Heo struct cpu_workqueue_struct __percpu *pcpu; 248bdbc5dd7STejun Heo struct cpu_workqueue_struct *single; 249bdbc5dd7STejun Heo unsigned long v; 250bdbc5dd7STejun Heo } cpu_wq; /* I: cwq's */ 2514690c4abSTejun Heo struct list_head list; /* W: list of all workqueues */ 25273f53c4aSTejun Heo 25373f53c4aSTejun Heo struct mutex flush_mutex; /* protects wq flushing */ 25473f53c4aSTejun Heo int work_color; /* F: current work color */ 25573f53c4aSTejun Heo int flush_color; /* F: current flush color */ 25673f53c4aSTejun Heo atomic_t nr_cwqs_to_flush; /* flush in progress */ 25773f53c4aSTejun Heo struct wq_flusher *first_flusher; /* F: first flusher */ 25873f53c4aSTejun Heo struct list_head flusher_queue; /* F: flush waiters */ 25973f53c4aSTejun Heo struct list_head flusher_overflow; /* F: flush overflow list */ 26073f53c4aSTejun Heo 261f2e005aaSTejun Heo mayday_mask_t mayday_mask; /* cpus requesting rescue */ 262e22bee78STejun Heo struct worker *rescuer; /* I: rescue worker */ 263e22bee78STejun Heo 2649c5a2ba7STejun Heo int nr_drainers; /* W: drain in progress */ 265dcd989cbSTejun Heo int saved_max_active; /* W: saved cwq max_active */ 2664e6045f1SJohannes Berg #ifdef CONFIG_LOCKDEP 2674e6045f1SJohannes Berg struct lockdep_map lockdep_map; 2684e6045f1SJohannes Berg #endif 269b196be89STejun Heo char name[]; /* I: workqueue name */ 2701da177e4SLinus Torvalds }; 2711da177e4SLinus Torvalds 272d320c038STejun Heo struct workqueue_struct *system_wq __read_mostly; 273d320c038STejun Heo EXPORT_SYMBOL_GPL(system_wq); 274044c782cSValentin Ilie struct workqueue_struct *system_highpri_wq __read_mostly; 2751aabe902SJoonsoo Kim EXPORT_SYMBOL_GPL(system_highpri_wq); 276044c782cSValentin Ilie struct workqueue_struct *system_long_wq __read_mostly; 277d320c038STejun Heo EXPORT_SYMBOL_GPL(system_long_wq); 278044c782cSValentin Ilie struct workqueue_struct *system_unbound_wq __read_mostly; 279f3421797STejun Heo EXPORT_SYMBOL_GPL(system_unbound_wq); 280044c782cSValentin Ilie struct workqueue_struct *system_freezable_wq __read_mostly; 28124d51addSTejun Heo EXPORT_SYMBOL_GPL(system_freezable_wq); 282d320c038STejun Heo 28397bd2347STejun Heo #define CREATE_TRACE_POINTS 28497bd2347STejun Heo #include <trace/events/workqueue.h> 28597bd2347STejun Heo 2864ce62e9eSTejun Heo #define for_each_worker_pool(pool, gcwq) \ 2873270476aSTejun Heo for ((pool) = &(gcwq)->pools[0]; \ 2883270476aSTejun Heo (pool) < &(gcwq)->pools[NR_WORKER_POOLS]; (pool)++) 2894ce62e9eSTejun Heo 290db7bccf4STejun Heo #define for_each_busy_worker(worker, i, pos, gcwq) \ 29142f8570fSSasha Levin hash_for_each(gcwq->busy_hash, i, pos, worker, hentry) 292db7bccf4STejun Heo 293f3421797STejun Heo static inline int __next_gcwq_cpu(int cpu, const struct cpumask *mask, 294f3421797STejun Heo unsigned int sw) 295f3421797STejun Heo { 296f3421797STejun Heo if (cpu < nr_cpu_ids) { 297f3421797STejun Heo if (sw & 1) { 298f3421797STejun Heo cpu = cpumask_next(cpu, mask); 299f3421797STejun Heo if (cpu < nr_cpu_ids) 300f3421797STejun Heo return cpu; 301f3421797STejun Heo } 302f3421797STejun Heo if (sw & 2) 303f3421797STejun Heo return WORK_CPU_UNBOUND; 304f3421797STejun Heo } 305f3421797STejun Heo return WORK_CPU_NONE; 306f3421797STejun Heo } 307f3421797STejun Heo 308f3421797STejun Heo static inline int __next_wq_cpu(int cpu, const struct cpumask *mask, 309f3421797STejun Heo struct workqueue_struct *wq) 310f3421797STejun Heo { 311f3421797STejun Heo return __next_gcwq_cpu(cpu, mask, !(wq->flags & WQ_UNBOUND) ? 1 : 2); 312f3421797STejun Heo } 313f3421797STejun Heo 31409884951STejun Heo /* 31509884951STejun Heo * CPU iterators 31609884951STejun Heo * 31709884951STejun Heo * An extra gcwq is defined for an invalid cpu number 31809884951STejun Heo * (WORK_CPU_UNBOUND) to host workqueues which are not bound to any 31909884951STejun Heo * specific CPU. The following iterators are similar to 32009884951STejun Heo * for_each_*_cpu() iterators but also considers the unbound gcwq. 32109884951STejun Heo * 32209884951STejun Heo * for_each_gcwq_cpu() : possible CPUs + WORK_CPU_UNBOUND 32309884951STejun Heo * for_each_online_gcwq_cpu() : online CPUs + WORK_CPU_UNBOUND 32409884951STejun Heo * for_each_cwq_cpu() : possible CPUs for bound workqueues, 32509884951STejun Heo * WORK_CPU_UNBOUND for unbound workqueues 32609884951STejun Heo */ 327f3421797STejun Heo #define for_each_gcwq_cpu(cpu) \ 328f3421797STejun Heo for ((cpu) = __next_gcwq_cpu(-1, cpu_possible_mask, 3); \ 329f3421797STejun Heo (cpu) < WORK_CPU_NONE; \ 330f3421797STejun Heo (cpu) = __next_gcwq_cpu((cpu), cpu_possible_mask, 3)) 331f3421797STejun Heo 332f3421797STejun Heo #define for_each_online_gcwq_cpu(cpu) \ 333f3421797STejun Heo for ((cpu) = __next_gcwq_cpu(-1, cpu_online_mask, 3); \ 334f3421797STejun Heo (cpu) < WORK_CPU_NONE; \ 335f3421797STejun Heo (cpu) = __next_gcwq_cpu((cpu), cpu_online_mask, 3)) 336f3421797STejun Heo 337f3421797STejun Heo #define for_each_cwq_cpu(cpu, wq) \ 338f3421797STejun Heo for ((cpu) = __next_wq_cpu(-1, cpu_possible_mask, (wq)); \ 339f3421797STejun Heo (cpu) < WORK_CPU_NONE; \ 340f3421797STejun Heo (cpu) = __next_wq_cpu((cpu), cpu_possible_mask, (wq))) 341f3421797STejun Heo 342dc186ad7SThomas Gleixner #ifdef CONFIG_DEBUG_OBJECTS_WORK 343dc186ad7SThomas Gleixner 344dc186ad7SThomas Gleixner static struct debug_obj_descr work_debug_descr; 345dc186ad7SThomas Gleixner 34699777288SStanislaw Gruszka static void *work_debug_hint(void *addr) 34799777288SStanislaw Gruszka { 34899777288SStanislaw Gruszka return ((struct work_struct *) addr)->func; 34999777288SStanislaw Gruszka } 35099777288SStanislaw Gruszka 351dc186ad7SThomas Gleixner /* 352dc186ad7SThomas Gleixner * fixup_init is called when: 353dc186ad7SThomas Gleixner * - an active object is initialized 354dc186ad7SThomas Gleixner */ 355dc186ad7SThomas Gleixner static int work_fixup_init(void *addr, enum debug_obj_state state) 356dc186ad7SThomas Gleixner { 357dc186ad7SThomas Gleixner struct work_struct *work = addr; 358dc186ad7SThomas Gleixner 359dc186ad7SThomas Gleixner switch (state) { 360dc186ad7SThomas Gleixner case ODEBUG_STATE_ACTIVE: 361dc186ad7SThomas Gleixner cancel_work_sync(work); 362dc186ad7SThomas Gleixner debug_object_init(work, &work_debug_descr); 363dc186ad7SThomas Gleixner return 1; 364dc186ad7SThomas Gleixner default: 365dc186ad7SThomas Gleixner return 0; 366dc186ad7SThomas Gleixner } 367dc186ad7SThomas Gleixner } 368dc186ad7SThomas Gleixner 369dc186ad7SThomas Gleixner /* 370dc186ad7SThomas Gleixner * fixup_activate is called when: 371dc186ad7SThomas Gleixner * - an active object is activated 372dc186ad7SThomas Gleixner * - an unknown object is activated (might be a statically initialized object) 373dc186ad7SThomas Gleixner */ 374dc186ad7SThomas Gleixner static int work_fixup_activate(void *addr, enum debug_obj_state state) 375dc186ad7SThomas Gleixner { 376dc186ad7SThomas Gleixner struct work_struct *work = addr; 377dc186ad7SThomas Gleixner 378dc186ad7SThomas Gleixner switch (state) { 379dc186ad7SThomas Gleixner 380dc186ad7SThomas Gleixner case ODEBUG_STATE_NOTAVAILABLE: 381dc186ad7SThomas Gleixner /* 382dc186ad7SThomas Gleixner * This is not really a fixup. The work struct was 383dc186ad7SThomas Gleixner * statically initialized. We just make sure that it 384dc186ad7SThomas Gleixner * is tracked in the object tracker. 385dc186ad7SThomas Gleixner */ 38622df02bbSTejun Heo if (test_bit(WORK_STRUCT_STATIC_BIT, work_data_bits(work))) { 387dc186ad7SThomas Gleixner debug_object_init(work, &work_debug_descr); 388dc186ad7SThomas Gleixner debug_object_activate(work, &work_debug_descr); 389dc186ad7SThomas Gleixner return 0; 390dc186ad7SThomas Gleixner } 391dc186ad7SThomas Gleixner WARN_ON_ONCE(1); 392dc186ad7SThomas Gleixner return 0; 393dc186ad7SThomas Gleixner 394dc186ad7SThomas Gleixner case ODEBUG_STATE_ACTIVE: 395dc186ad7SThomas Gleixner WARN_ON(1); 396dc186ad7SThomas Gleixner 397dc186ad7SThomas Gleixner default: 398dc186ad7SThomas Gleixner return 0; 399dc186ad7SThomas Gleixner } 400dc186ad7SThomas Gleixner } 401dc186ad7SThomas Gleixner 402dc186ad7SThomas Gleixner /* 403dc186ad7SThomas Gleixner * fixup_free is called when: 404dc186ad7SThomas Gleixner * - an active object is freed 405dc186ad7SThomas Gleixner */ 406dc186ad7SThomas Gleixner static int work_fixup_free(void *addr, enum debug_obj_state state) 407dc186ad7SThomas Gleixner { 408dc186ad7SThomas Gleixner struct work_struct *work = addr; 409dc186ad7SThomas Gleixner 410dc186ad7SThomas Gleixner switch (state) { 411dc186ad7SThomas Gleixner case ODEBUG_STATE_ACTIVE: 412dc186ad7SThomas Gleixner cancel_work_sync(work); 413dc186ad7SThomas Gleixner debug_object_free(work, &work_debug_descr); 414dc186ad7SThomas Gleixner return 1; 415dc186ad7SThomas Gleixner default: 416dc186ad7SThomas Gleixner return 0; 417dc186ad7SThomas Gleixner } 418dc186ad7SThomas Gleixner } 419dc186ad7SThomas Gleixner 420dc186ad7SThomas Gleixner static struct debug_obj_descr work_debug_descr = { 421dc186ad7SThomas Gleixner .name = "work_struct", 42299777288SStanislaw Gruszka .debug_hint = work_debug_hint, 423dc186ad7SThomas Gleixner .fixup_init = work_fixup_init, 424dc186ad7SThomas Gleixner .fixup_activate = work_fixup_activate, 425dc186ad7SThomas Gleixner .fixup_free = work_fixup_free, 426dc186ad7SThomas Gleixner }; 427dc186ad7SThomas Gleixner 428dc186ad7SThomas Gleixner static inline void debug_work_activate(struct work_struct *work) 429dc186ad7SThomas Gleixner { 430dc186ad7SThomas Gleixner debug_object_activate(work, &work_debug_descr); 431dc186ad7SThomas Gleixner } 432dc186ad7SThomas Gleixner 433dc186ad7SThomas Gleixner static inline void debug_work_deactivate(struct work_struct *work) 434dc186ad7SThomas Gleixner { 435dc186ad7SThomas Gleixner debug_object_deactivate(work, &work_debug_descr); 436dc186ad7SThomas Gleixner } 437dc186ad7SThomas Gleixner 438dc186ad7SThomas Gleixner void __init_work(struct work_struct *work, int onstack) 439dc186ad7SThomas Gleixner { 440dc186ad7SThomas Gleixner if (onstack) 441dc186ad7SThomas Gleixner debug_object_init_on_stack(work, &work_debug_descr); 442dc186ad7SThomas Gleixner else 443dc186ad7SThomas Gleixner debug_object_init(work, &work_debug_descr); 444dc186ad7SThomas Gleixner } 445dc186ad7SThomas Gleixner EXPORT_SYMBOL_GPL(__init_work); 446dc186ad7SThomas Gleixner 447dc186ad7SThomas Gleixner void destroy_work_on_stack(struct work_struct *work) 448dc186ad7SThomas Gleixner { 449dc186ad7SThomas Gleixner debug_object_free(work, &work_debug_descr); 450dc186ad7SThomas Gleixner } 451dc186ad7SThomas Gleixner EXPORT_SYMBOL_GPL(destroy_work_on_stack); 452dc186ad7SThomas Gleixner 453dc186ad7SThomas Gleixner #else 454dc186ad7SThomas Gleixner static inline void debug_work_activate(struct work_struct *work) { } 455dc186ad7SThomas Gleixner static inline void debug_work_deactivate(struct work_struct *work) { } 456dc186ad7SThomas Gleixner #endif 457dc186ad7SThomas Gleixner 45895402b38SGautham R Shenoy /* Serializes the accesses to the list of workqueues. */ 45995402b38SGautham R Shenoy static DEFINE_SPINLOCK(workqueue_lock); 4601da177e4SLinus Torvalds static LIST_HEAD(workqueues); 461a0a1a5fdSTejun Heo static bool workqueue_freezing; /* W: have wqs started freezing? */ 4621da177e4SLinus Torvalds 46314441960SOleg Nesterov /* 464e22bee78STejun Heo * The almighty global cpu workqueues. nr_running is the only field 465e22bee78STejun Heo * which is expected to be used frequently by other cpus via 466e22bee78STejun Heo * try_to_wake_up(). Put it in a separate cacheline. 46714441960SOleg Nesterov */ 4688b03ae3cSTejun Heo static DEFINE_PER_CPU(struct global_cwq, global_cwq); 4694ce62e9eSTejun Heo static DEFINE_PER_CPU_SHARED_ALIGNED(atomic_t, pool_nr_running[NR_WORKER_POOLS]); 470f756d5e2SNathan Lynch 471f3421797STejun Heo /* 472f3421797STejun Heo * Global cpu workqueue and nr_running counter for unbound gcwq. The 473f3421797STejun Heo * gcwq is always online, has GCWQ_DISASSOCIATED set, and all its 474f3421797STejun Heo * workers have WORKER_UNBOUND set. 475f3421797STejun Heo */ 476f3421797STejun Heo static struct global_cwq unbound_global_cwq; 4774ce62e9eSTejun Heo static atomic_t unbound_pool_nr_running[NR_WORKER_POOLS] = { 4784ce62e9eSTejun Heo [0 ... NR_WORKER_POOLS - 1] = ATOMIC_INIT(0), /* always 0 */ 4794ce62e9eSTejun Heo }; 480f3421797STejun Heo 481c34056a3STejun Heo static int worker_thread(void *__worker); 4821da177e4SLinus Torvalds 4833270476aSTejun Heo static int worker_pool_pri(struct worker_pool *pool) 4843270476aSTejun Heo { 4853270476aSTejun Heo return pool - pool->gcwq->pools; 4863270476aSTejun Heo } 4873270476aSTejun Heo 4888b03ae3cSTejun Heo static struct global_cwq *get_gcwq(unsigned int cpu) 4891da177e4SLinus Torvalds { 490f3421797STejun Heo if (cpu != WORK_CPU_UNBOUND) 4918b03ae3cSTejun Heo return &per_cpu(global_cwq, cpu); 492f3421797STejun Heo else 493f3421797STejun Heo return &unbound_global_cwq; 4941da177e4SLinus Torvalds } 4951da177e4SLinus Torvalds 49663d95a91STejun Heo static atomic_t *get_pool_nr_running(struct worker_pool *pool) 497b1f4ec17SOleg Nesterov { 49863d95a91STejun Heo int cpu = pool->gcwq->cpu; 4993270476aSTejun Heo int idx = worker_pool_pri(pool); 50063d95a91STejun Heo 501f3421797STejun Heo if (cpu != WORK_CPU_UNBOUND) 5024ce62e9eSTejun Heo return &per_cpu(pool_nr_running, cpu)[idx]; 503f3421797STejun Heo else 5044ce62e9eSTejun Heo return &unbound_pool_nr_running[idx]; 505b1f4ec17SOleg Nesterov } 506b1f4ec17SOleg Nesterov 5074690c4abSTejun Heo static struct cpu_workqueue_struct *get_cwq(unsigned int cpu, 5084690c4abSTejun Heo struct workqueue_struct *wq) 509a848e3b6SOleg Nesterov { 510f3421797STejun Heo if (!(wq->flags & WQ_UNBOUND)) { 511e06ffa1eSLai Jiangshan if (likely(cpu < nr_cpu_ids)) 512bdbc5dd7STejun Heo return per_cpu_ptr(wq->cpu_wq.pcpu, cpu); 513f3421797STejun Heo } else if (likely(cpu == WORK_CPU_UNBOUND)) 514f3421797STejun Heo return wq->cpu_wq.single; 515f3421797STejun Heo return NULL; 516f3421797STejun Heo } 517a848e3b6SOleg Nesterov 51873f53c4aSTejun Heo static unsigned int work_color_to_flags(int color) 51973f53c4aSTejun Heo { 52073f53c4aSTejun Heo return color << WORK_STRUCT_COLOR_SHIFT; 52173f53c4aSTejun Heo } 52273f53c4aSTejun Heo 52373f53c4aSTejun Heo static int get_work_color(struct work_struct *work) 52473f53c4aSTejun Heo { 52573f53c4aSTejun Heo return (*work_data_bits(work) >> WORK_STRUCT_COLOR_SHIFT) & 52673f53c4aSTejun Heo ((1 << WORK_STRUCT_COLOR_BITS) - 1); 52773f53c4aSTejun Heo } 52873f53c4aSTejun Heo 52973f53c4aSTejun Heo static int work_next_color(int color) 53073f53c4aSTejun Heo { 53173f53c4aSTejun Heo return (color + 1) % WORK_NR_COLORS; 5321da177e4SLinus Torvalds } 5331da177e4SLinus Torvalds 5344594bf15SDavid Howells /* 535b5490077STejun Heo * While queued, %WORK_STRUCT_CWQ is set and non flag bits of a work's data 536b5490077STejun Heo * contain the pointer to the queued cwq. Once execution starts, the flag 537b5490077STejun Heo * is cleared and the high bits contain OFFQ flags and CPU number. 5387a22ad75STejun Heo * 539bbb68dfaSTejun Heo * set_work_cwq(), set_work_cpu_and_clear_pending(), mark_work_canceling() 540bbb68dfaSTejun Heo * and clear_work_data() can be used to set the cwq, cpu or clear 541bbb68dfaSTejun Heo * work->data. These functions should only be called while the work is 542bbb68dfaSTejun Heo * owned - ie. while the PENDING bit is set. 5437a22ad75STejun Heo * 544bbb68dfaSTejun Heo * get_work_[g]cwq() can be used to obtain the gcwq or cwq corresponding to 545bbb68dfaSTejun Heo * a work. gcwq is available once the work has been queued anywhere after 546bbb68dfaSTejun Heo * initialization until it is sync canceled. cwq is available only while 547bbb68dfaSTejun Heo * the work item is queued. 548bbb68dfaSTejun Heo * 549bbb68dfaSTejun Heo * %WORK_OFFQ_CANCELING is used to mark a work item which is being 550bbb68dfaSTejun Heo * canceled. While being canceled, a work item may have its PENDING set 551bbb68dfaSTejun Heo * but stay off timer and worklist for arbitrarily long and nobody should 552bbb68dfaSTejun Heo * try to steal the PENDING bit. 5534594bf15SDavid Howells */ 5547a22ad75STejun Heo static inline void set_work_data(struct work_struct *work, unsigned long data, 5557a22ad75STejun Heo unsigned long flags) 5567a22ad75STejun Heo { 5577a22ad75STejun Heo BUG_ON(!work_pending(work)); 5587a22ad75STejun Heo atomic_long_set(&work->data, data | flags | work_static(work)); 5597a22ad75STejun Heo } 5607a22ad75STejun Heo 5617a22ad75STejun Heo static void set_work_cwq(struct work_struct *work, 5624690c4abSTejun Heo struct cpu_workqueue_struct *cwq, 5634690c4abSTejun Heo unsigned long extra_flags) 564365970a1SDavid Howells { 5657a22ad75STejun Heo set_work_data(work, (unsigned long)cwq, 566e120153dSTejun Heo WORK_STRUCT_PENDING | WORK_STRUCT_CWQ | extra_flags); 567365970a1SDavid Howells } 568365970a1SDavid Howells 5698930cabaSTejun Heo static void set_work_cpu_and_clear_pending(struct work_struct *work, 5708930cabaSTejun Heo unsigned int cpu) 5714d707b9fSOleg Nesterov { 57223657bb1STejun Heo /* 57323657bb1STejun Heo * The following wmb is paired with the implied mb in 57423657bb1STejun Heo * test_and_set_bit(PENDING) and ensures all updates to @work made 57523657bb1STejun Heo * here are visible to and precede any updates by the next PENDING 57623657bb1STejun Heo * owner. 57723657bb1STejun Heo */ 57823657bb1STejun Heo smp_wmb(); 579b5490077STejun Heo set_work_data(work, (unsigned long)cpu << WORK_OFFQ_CPU_SHIFT, 0); 5804d707b9fSOleg Nesterov } 5814d707b9fSOleg Nesterov 5827a22ad75STejun Heo static void clear_work_data(struct work_struct *work) 583365970a1SDavid Howells { 58423657bb1STejun Heo smp_wmb(); /* see set_work_cpu_and_clear_pending() */ 5857a22ad75STejun Heo set_work_data(work, WORK_STRUCT_NO_CPU, 0); 5867a22ad75STejun Heo } 5877a22ad75STejun Heo 5887a22ad75STejun Heo static struct cpu_workqueue_struct *get_work_cwq(struct work_struct *work) 5897a22ad75STejun Heo { 590e120153dSTejun Heo unsigned long data = atomic_long_read(&work->data); 5917a22ad75STejun Heo 592e120153dSTejun Heo if (data & WORK_STRUCT_CWQ) 593e120153dSTejun Heo return (void *)(data & WORK_STRUCT_WQ_DATA_MASK); 594e120153dSTejun Heo else 595e120153dSTejun Heo return NULL; 5967a22ad75STejun Heo } 5977a22ad75STejun Heo 5987a22ad75STejun Heo static struct global_cwq *get_work_gcwq(struct work_struct *work) 5997a22ad75STejun Heo { 600e120153dSTejun Heo unsigned long data = atomic_long_read(&work->data); 6017a22ad75STejun Heo unsigned int cpu; 6027a22ad75STejun Heo 603e120153dSTejun Heo if (data & WORK_STRUCT_CWQ) 604e120153dSTejun Heo return ((struct cpu_workqueue_struct *) 605bd7bdd43STejun Heo (data & WORK_STRUCT_WQ_DATA_MASK))->pool->gcwq; 6067a22ad75STejun Heo 607b5490077STejun Heo cpu = data >> WORK_OFFQ_CPU_SHIFT; 608bdbc5dd7STejun Heo if (cpu == WORK_CPU_NONE) 6097a22ad75STejun Heo return NULL; 6107a22ad75STejun Heo 611f3421797STejun Heo BUG_ON(cpu >= nr_cpu_ids && cpu != WORK_CPU_UNBOUND); 6127a22ad75STejun Heo return get_gcwq(cpu); 613365970a1SDavid Howells } 614365970a1SDavid Howells 615bbb68dfaSTejun Heo static void mark_work_canceling(struct work_struct *work) 616bbb68dfaSTejun Heo { 617bbb68dfaSTejun Heo struct global_cwq *gcwq = get_work_gcwq(work); 618bbb68dfaSTejun Heo unsigned long cpu = gcwq ? gcwq->cpu : WORK_CPU_NONE; 619bbb68dfaSTejun Heo 620bbb68dfaSTejun Heo set_work_data(work, (cpu << WORK_OFFQ_CPU_SHIFT) | WORK_OFFQ_CANCELING, 621bbb68dfaSTejun Heo WORK_STRUCT_PENDING); 622bbb68dfaSTejun Heo } 623bbb68dfaSTejun Heo 624bbb68dfaSTejun Heo static bool work_is_canceling(struct work_struct *work) 625bbb68dfaSTejun Heo { 626bbb68dfaSTejun Heo unsigned long data = atomic_long_read(&work->data); 627bbb68dfaSTejun Heo 628bbb68dfaSTejun Heo return !(data & WORK_STRUCT_CWQ) && (data & WORK_OFFQ_CANCELING); 629bbb68dfaSTejun Heo } 630bbb68dfaSTejun Heo 631e22bee78STejun Heo /* 6323270476aSTejun Heo * Policy functions. These define the policies on how the global worker 6333270476aSTejun Heo * pools are managed. Unless noted otherwise, these functions assume that 6343270476aSTejun Heo * they're being called with gcwq->lock held. 635e22bee78STejun Heo */ 636e22bee78STejun Heo 63763d95a91STejun Heo static bool __need_more_worker(struct worker_pool *pool) 638649027d7STejun Heo { 6393270476aSTejun Heo return !atomic_read(get_pool_nr_running(pool)); 640649027d7STejun Heo } 641649027d7STejun Heo 642e22bee78STejun Heo /* 643e22bee78STejun Heo * Need to wake up a worker? Called from anything but currently 644e22bee78STejun Heo * running workers. 645974271c4STejun Heo * 646974271c4STejun Heo * Note that, because unbound workers never contribute to nr_running, this 647974271c4STejun Heo * function will always return %true for unbound gcwq as long as the 648974271c4STejun Heo * worklist isn't empty. 649e22bee78STejun Heo */ 65063d95a91STejun Heo static bool need_more_worker(struct worker_pool *pool) 651e22bee78STejun Heo { 65263d95a91STejun Heo return !list_empty(&pool->worklist) && __need_more_worker(pool); 653e22bee78STejun Heo } 654e22bee78STejun Heo 655e22bee78STejun Heo /* Can I start working? Called from busy but !running workers. */ 65663d95a91STejun Heo static bool may_start_working(struct worker_pool *pool) 657e22bee78STejun Heo { 65863d95a91STejun Heo return pool->nr_idle; 659e22bee78STejun Heo } 660e22bee78STejun Heo 661e22bee78STejun Heo /* Do I need to keep working? Called from currently running workers. */ 66263d95a91STejun Heo static bool keep_working(struct worker_pool *pool) 663e22bee78STejun Heo { 66463d95a91STejun Heo atomic_t *nr_running = get_pool_nr_running(pool); 665e22bee78STejun Heo 6663270476aSTejun Heo return !list_empty(&pool->worklist) && atomic_read(nr_running) <= 1; 667e22bee78STejun Heo } 668e22bee78STejun Heo 669e22bee78STejun Heo /* Do we need a new worker? Called from manager. */ 67063d95a91STejun Heo static bool need_to_create_worker(struct worker_pool *pool) 671e22bee78STejun Heo { 67263d95a91STejun Heo return need_more_worker(pool) && !may_start_working(pool); 673e22bee78STejun Heo } 674e22bee78STejun Heo 675e22bee78STejun Heo /* Do I need to be the manager? */ 67663d95a91STejun Heo static bool need_to_manage_workers(struct worker_pool *pool) 677e22bee78STejun Heo { 67863d95a91STejun Heo return need_to_create_worker(pool) || 67911ebea50STejun Heo (pool->flags & POOL_MANAGE_WORKERS); 680e22bee78STejun Heo } 681e22bee78STejun Heo 682e22bee78STejun Heo /* Do we have too many workers and should some go away? */ 68363d95a91STejun Heo static bool too_many_workers(struct worker_pool *pool) 684e22bee78STejun Heo { 685552a37e9SLai Jiangshan bool managing = pool->flags & POOL_MANAGING_WORKERS; 68663d95a91STejun Heo int nr_idle = pool->nr_idle + managing; /* manager is considered idle */ 68763d95a91STejun Heo int nr_busy = pool->nr_workers - nr_idle; 688e22bee78STejun Heo 689ea1abd61SLai Jiangshan /* 690ea1abd61SLai Jiangshan * nr_idle and idle_list may disagree if idle rebinding is in 691ea1abd61SLai Jiangshan * progress. Never return %true if idle_list is empty. 692ea1abd61SLai Jiangshan */ 693ea1abd61SLai Jiangshan if (list_empty(&pool->idle_list)) 694ea1abd61SLai Jiangshan return false; 695ea1abd61SLai Jiangshan 696e22bee78STejun Heo return nr_idle > 2 && (nr_idle - 2) * MAX_IDLE_WORKERS_RATIO >= nr_busy; 697e22bee78STejun Heo } 698e22bee78STejun Heo 699e22bee78STejun Heo /* 700e22bee78STejun Heo * Wake up functions. 701e22bee78STejun Heo */ 702e22bee78STejun Heo 7037e11629dSTejun Heo /* Return the first worker. Safe with preemption disabled */ 70463d95a91STejun Heo static struct worker *first_worker(struct worker_pool *pool) 7057e11629dSTejun Heo { 70663d95a91STejun Heo if (unlikely(list_empty(&pool->idle_list))) 7077e11629dSTejun Heo return NULL; 7087e11629dSTejun Heo 70963d95a91STejun Heo return list_first_entry(&pool->idle_list, struct worker, entry); 7107e11629dSTejun Heo } 7117e11629dSTejun Heo 7127e11629dSTejun Heo /** 7137e11629dSTejun Heo * wake_up_worker - wake up an idle worker 71463d95a91STejun Heo * @pool: worker pool to wake worker from 7157e11629dSTejun Heo * 71663d95a91STejun Heo * Wake up the first idle worker of @pool. 7177e11629dSTejun Heo * 7187e11629dSTejun Heo * CONTEXT: 7197e11629dSTejun Heo * spin_lock_irq(gcwq->lock). 7207e11629dSTejun Heo */ 72163d95a91STejun Heo static void wake_up_worker(struct worker_pool *pool) 7227e11629dSTejun Heo { 72363d95a91STejun Heo struct worker *worker = first_worker(pool); 7247e11629dSTejun Heo 7257e11629dSTejun Heo if (likely(worker)) 7267e11629dSTejun Heo wake_up_process(worker->task); 7277e11629dSTejun Heo } 7287e11629dSTejun Heo 7294690c4abSTejun Heo /** 730e22bee78STejun Heo * wq_worker_waking_up - a worker is waking up 731e22bee78STejun Heo * @task: task waking up 732e22bee78STejun Heo * @cpu: CPU @task is waking up to 733e22bee78STejun Heo * 734e22bee78STejun Heo * This function is called during try_to_wake_up() when a worker is 735e22bee78STejun Heo * being awoken. 736e22bee78STejun Heo * 737e22bee78STejun Heo * CONTEXT: 738e22bee78STejun Heo * spin_lock_irq(rq->lock) 739e22bee78STejun Heo */ 740e22bee78STejun Heo void wq_worker_waking_up(struct task_struct *task, unsigned int cpu) 741e22bee78STejun Heo { 742e22bee78STejun Heo struct worker *worker = kthread_data(task); 743e22bee78STejun Heo 74436576000SJoonsoo Kim if (!(worker->flags & WORKER_NOT_RUNNING)) { 74536576000SJoonsoo Kim WARN_ON_ONCE(worker->pool->gcwq->cpu != cpu); 74663d95a91STejun Heo atomic_inc(get_pool_nr_running(worker->pool)); 747e22bee78STejun Heo } 74836576000SJoonsoo Kim } 749e22bee78STejun Heo 750e22bee78STejun Heo /** 751e22bee78STejun Heo * wq_worker_sleeping - a worker is going to sleep 752e22bee78STejun Heo * @task: task going to sleep 753e22bee78STejun Heo * @cpu: CPU in question, must be the current CPU number 754e22bee78STejun Heo * 755e22bee78STejun Heo * This function is called during schedule() when a busy worker is 756e22bee78STejun Heo * going to sleep. Worker on the same cpu can be woken up by 757e22bee78STejun Heo * returning pointer to its task. 758e22bee78STejun Heo * 759e22bee78STejun Heo * CONTEXT: 760e22bee78STejun Heo * spin_lock_irq(rq->lock) 761e22bee78STejun Heo * 762e22bee78STejun Heo * RETURNS: 763e22bee78STejun Heo * Worker task on @cpu to wake up, %NULL if none. 764e22bee78STejun Heo */ 765e22bee78STejun Heo struct task_struct *wq_worker_sleeping(struct task_struct *task, 766e22bee78STejun Heo unsigned int cpu) 767e22bee78STejun Heo { 768e22bee78STejun Heo struct worker *worker = kthread_data(task), *to_wakeup = NULL; 769111c225aSTejun Heo struct worker_pool *pool; 770111c225aSTejun Heo atomic_t *nr_running; 771e22bee78STejun Heo 772111c225aSTejun Heo /* 773111c225aSTejun Heo * Rescuers, which may not have all the fields set up like normal 774111c225aSTejun Heo * workers, also reach here, let's not access anything before 775111c225aSTejun Heo * checking NOT_RUNNING. 776111c225aSTejun Heo */ 7772d64672eSSteven Rostedt if (worker->flags & WORKER_NOT_RUNNING) 778e22bee78STejun Heo return NULL; 779e22bee78STejun Heo 780111c225aSTejun Heo pool = worker->pool; 781111c225aSTejun Heo nr_running = get_pool_nr_running(pool); 782111c225aSTejun Heo 783e22bee78STejun Heo /* this can only happen on the local cpu */ 784e22bee78STejun Heo BUG_ON(cpu != raw_smp_processor_id()); 785e22bee78STejun Heo 786e22bee78STejun Heo /* 787e22bee78STejun Heo * The counterpart of the following dec_and_test, implied mb, 788e22bee78STejun Heo * worklist not empty test sequence is in insert_work(). 789e22bee78STejun Heo * Please read comment there. 790e22bee78STejun Heo * 791628c78e7STejun Heo * NOT_RUNNING is clear. This means that we're bound to and 792628c78e7STejun Heo * running on the local cpu w/ rq lock held and preemption 793628c78e7STejun Heo * disabled, which in turn means that none else could be 794628c78e7STejun Heo * manipulating idle_list, so dereferencing idle_list without gcwq 795628c78e7STejun Heo * lock is safe. 796e22bee78STejun Heo */ 797bd7bdd43STejun Heo if (atomic_dec_and_test(nr_running) && !list_empty(&pool->worklist)) 79863d95a91STejun Heo to_wakeup = first_worker(pool); 799e22bee78STejun Heo return to_wakeup ? to_wakeup->task : NULL; 800e22bee78STejun Heo } 801e22bee78STejun Heo 802e22bee78STejun Heo /** 803e22bee78STejun Heo * worker_set_flags - set worker flags and adjust nr_running accordingly 804cb444766STejun Heo * @worker: self 805d302f017STejun Heo * @flags: flags to set 806d302f017STejun Heo * @wakeup: wakeup an idle worker if necessary 807d302f017STejun Heo * 808e22bee78STejun Heo * Set @flags in @worker->flags and adjust nr_running accordingly. If 809e22bee78STejun Heo * nr_running becomes zero and @wakeup is %true, an idle worker is 810e22bee78STejun Heo * woken up. 811d302f017STejun Heo * 812cb444766STejun Heo * CONTEXT: 813cb444766STejun Heo * spin_lock_irq(gcwq->lock) 814d302f017STejun Heo */ 815d302f017STejun Heo static inline void worker_set_flags(struct worker *worker, unsigned int flags, 816d302f017STejun Heo bool wakeup) 817d302f017STejun Heo { 818bd7bdd43STejun Heo struct worker_pool *pool = worker->pool; 819e22bee78STejun Heo 820cb444766STejun Heo WARN_ON_ONCE(worker->task != current); 821cb444766STejun Heo 822e22bee78STejun Heo /* 823e22bee78STejun Heo * If transitioning into NOT_RUNNING, adjust nr_running and 824e22bee78STejun Heo * wake up an idle worker as necessary if requested by 825e22bee78STejun Heo * @wakeup. 826e22bee78STejun Heo */ 827e22bee78STejun Heo if ((flags & WORKER_NOT_RUNNING) && 828e22bee78STejun Heo !(worker->flags & WORKER_NOT_RUNNING)) { 82963d95a91STejun Heo atomic_t *nr_running = get_pool_nr_running(pool); 830e22bee78STejun Heo 831e22bee78STejun Heo if (wakeup) { 832e22bee78STejun Heo if (atomic_dec_and_test(nr_running) && 833bd7bdd43STejun Heo !list_empty(&pool->worklist)) 83463d95a91STejun Heo wake_up_worker(pool); 835e22bee78STejun Heo } else 836e22bee78STejun Heo atomic_dec(nr_running); 837e22bee78STejun Heo } 838e22bee78STejun Heo 839d302f017STejun Heo worker->flags |= flags; 840d302f017STejun Heo } 841d302f017STejun Heo 842d302f017STejun Heo /** 843e22bee78STejun Heo * worker_clr_flags - clear worker flags and adjust nr_running accordingly 844cb444766STejun Heo * @worker: self 845d302f017STejun Heo * @flags: flags to clear 846d302f017STejun Heo * 847e22bee78STejun Heo * Clear @flags in @worker->flags and adjust nr_running accordingly. 848d302f017STejun Heo * 849cb444766STejun Heo * CONTEXT: 850cb444766STejun Heo * spin_lock_irq(gcwq->lock) 851d302f017STejun Heo */ 852d302f017STejun Heo static inline void worker_clr_flags(struct worker *worker, unsigned int flags) 853d302f017STejun Heo { 85463d95a91STejun Heo struct worker_pool *pool = worker->pool; 855e22bee78STejun Heo unsigned int oflags = worker->flags; 856e22bee78STejun Heo 857cb444766STejun Heo WARN_ON_ONCE(worker->task != current); 858cb444766STejun Heo 859d302f017STejun Heo worker->flags &= ~flags; 860e22bee78STejun Heo 86142c025f3STejun Heo /* 86242c025f3STejun Heo * If transitioning out of NOT_RUNNING, increment nr_running. Note 86342c025f3STejun Heo * that the nested NOT_RUNNING is not a noop. NOT_RUNNING is mask 86442c025f3STejun Heo * of multiple flags, not a single flag. 86542c025f3STejun Heo */ 866e22bee78STejun Heo if ((flags & WORKER_NOT_RUNNING) && (oflags & WORKER_NOT_RUNNING)) 867e22bee78STejun Heo if (!(worker->flags & WORKER_NOT_RUNNING)) 86863d95a91STejun Heo atomic_inc(get_pool_nr_running(pool)); 869d302f017STejun Heo } 870d302f017STejun Heo 871d302f017STejun Heo /** 8728cca0eeaSTejun Heo * find_worker_executing_work - find worker which is executing a work 8738cca0eeaSTejun Heo * @gcwq: gcwq of interest 8748cca0eeaSTejun Heo * @work: work to find worker for 8758cca0eeaSTejun Heo * 876a2c1c57bSTejun Heo * Find a worker which is executing @work on @gcwq by searching 877a2c1c57bSTejun Heo * @gcwq->busy_hash which is keyed by the address of @work. For a worker 878a2c1c57bSTejun Heo * to match, its current execution should match the address of @work and 879a2c1c57bSTejun Heo * its work function. This is to avoid unwanted dependency between 880a2c1c57bSTejun Heo * unrelated work executions through a work item being recycled while still 881a2c1c57bSTejun Heo * being executed. 882a2c1c57bSTejun Heo * 883a2c1c57bSTejun Heo * This is a bit tricky. A work item may be freed once its execution 884a2c1c57bSTejun Heo * starts and nothing prevents the freed area from being recycled for 885a2c1c57bSTejun Heo * another work item. If the same work item address ends up being reused 886a2c1c57bSTejun Heo * before the original execution finishes, workqueue will identify the 887a2c1c57bSTejun Heo * recycled work item as currently executing and make it wait until the 888a2c1c57bSTejun Heo * current execution finishes, introducing an unwanted dependency. 889a2c1c57bSTejun Heo * 890a2c1c57bSTejun Heo * This function checks the work item address, work function and workqueue 891a2c1c57bSTejun Heo * to avoid false positives. Note that this isn't complete as one may 892a2c1c57bSTejun Heo * construct a work function which can introduce dependency onto itself 893a2c1c57bSTejun Heo * through a recycled work item. Well, if somebody wants to shoot oneself 894a2c1c57bSTejun Heo * in the foot that badly, there's only so much we can do, and if such 895a2c1c57bSTejun Heo * deadlock actually occurs, it should be easy to locate the culprit work 896a2c1c57bSTejun Heo * function. 8978cca0eeaSTejun Heo * 8988cca0eeaSTejun Heo * CONTEXT: 8998cca0eeaSTejun Heo * spin_lock_irq(gcwq->lock). 9008cca0eeaSTejun Heo * 9018cca0eeaSTejun Heo * RETURNS: 9028cca0eeaSTejun Heo * Pointer to worker which is executing @work if found, NULL 9038cca0eeaSTejun Heo * otherwise. 9048cca0eeaSTejun Heo */ 9058cca0eeaSTejun Heo static struct worker *find_worker_executing_work(struct global_cwq *gcwq, 9068cca0eeaSTejun Heo struct work_struct *work) 9078cca0eeaSTejun Heo { 90842f8570fSSasha Levin struct worker *worker; 90942f8570fSSasha Levin struct hlist_node *tmp; 91042f8570fSSasha Levin 911a2c1c57bSTejun Heo hash_for_each_possible(gcwq->busy_hash, worker, tmp, hentry, 912a2c1c57bSTejun Heo (unsigned long)work) 913a2c1c57bSTejun Heo if (worker->current_work == work && 914a2c1c57bSTejun Heo worker->current_func == work->func) 91542f8570fSSasha Levin return worker; 91642f8570fSSasha Levin 91742f8570fSSasha Levin return NULL; 9188cca0eeaSTejun Heo } 9198cca0eeaSTejun Heo 9208cca0eeaSTejun Heo /** 921bf4ede01STejun Heo * move_linked_works - move linked works to a list 922bf4ede01STejun Heo * @work: start of series of works to be scheduled 923bf4ede01STejun Heo * @head: target list to append @work to 924bf4ede01STejun Heo * @nextp: out paramter for nested worklist walking 925bf4ede01STejun Heo * 926bf4ede01STejun Heo * Schedule linked works starting from @work to @head. Work series to 927bf4ede01STejun Heo * be scheduled starts at @work and includes any consecutive work with 928bf4ede01STejun Heo * WORK_STRUCT_LINKED set in its predecessor. 929bf4ede01STejun Heo * 930bf4ede01STejun Heo * If @nextp is not NULL, it's updated to point to the next work of 931bf4ede01STejun Heo * the last scheduled work. This allows move_linked_works() to be 932bf4ede01STejun Heo * nested inside outer list_for_each_entry_safe(). 933bf4ede01STejun Heo * 934bf4ede01STejun Heo * CONTEXT: 935bf4ede01STejun Heo * spin_lock_irq(gcwq->lock). 936bf4ede01STejun Heo */ 937bf4ede01STejun Heo static void move_linked_works(struct work_struct *work, struct list_head *head, 938bf4ede01STejun Heo struct work_struct **nextp) 939bf4ede01STejun Heo { 940bf4ede01STejun Heo struct work_struct *n; 941bf4ede01STejun Heo 942bf4ede01STejun Heo /* 943bf4ede01STejun Heo * Linked worklist will always end before the end of the list, 944bf4ede01STejun Heo * use NULL for list head. 945bf4ede01STejun Heo */ 946bf4ede01STejun Heo list_for_each_entry_safe_from(work, n, NULL, entry) { 947bf4ede01STejun Heo list_move_tail(&work->entry, head); 948bf4ede01STejun Heo if (!(*work_data_bits(work) & WORK_STRUCT_LINKED)) 949bf4ede01STejun Heo break; 950bf4ede01STejun Heo } 951bf4ede01STejun Heo 952bf4ede01STejun Heo /* 953bf4ede01STejun Heo * If we're already inside safe list traversal and have moved 954bf4ede01STejun Heo * multiple works to the scheduled queue, the next position 955bf4ede01STejun Heo * needs to be updated. 956bf4ede01STejun Heo */ 957bf4ede01STejun Heo if (nextp) 958bf4ede01STejun Heo *nextp = n; 959bf4ede01STejun Heo } 960bf4ede01STejun Heo 9613aa62497SLai Jiangshan static void cwq_activate_delayed_work(struct work_struct *work) 962bf4ede01STejun Heo { 9633aa62497SLai Jiangshan struct cpu_workqueue_struct *cwq = get_work_cwq(work); 964bf4ede01STejun Heo 965bf4ede01STejun Heo trace_workqueue_activate_work(work); 966bf4ede01STejun Heo move_linked_works(work, &cwq->pool->worklist, NULL); 967bf4ede01STejun Heo __clear_bit(WORK_STRUCT_DELAYED_BIT, work_data_bits(work)); 968bf4ede01STejun Heo cwq->nr_active++; 969bf4ede01STejun Heo } 970bf4ede01STejun Heo 9713aa62497SLai Jiangshan static void cwq_activate_first_delayed(struct cpu_workqueue_struct *cwq) 9723aa62497SLai Jiangshan { 9733aa62497SLai Jiangshan struct work_struct *work = list_first_entry(&cwq->delayed_works, 9743aa62497SLai Jiangshan struct work_struct, entry); 9753aa62497SLai Jiangshan 9763aa62497SLai Jiangshan cwq_activate_delayed_work(work); 9773aa62497SLai Jiangshan } 9783aa62497SLai Jiangshan 979bf4ede01STejun Heo /** 980bf4ede01STejun Heo * cwq_dec_nr_in_flight - decrement cwq's nr_in_flight 981bf4ede01STejun Heo * @cwq: cwq of interest 982bf4ede01STejun Heo * @color: color of work which left the queue 983bf4ede01STejun Heo * 984bf4ede01STejun Heo * A work either has completed or is removed from pending queue, 985bf4ede01STejun Heo * decrement nr_in_flight of its cwq and handle workqueue flushing. 986bf4ede01STejun Heo * 987bf4ede01STejun Heo * CONTEXT: 988bf4ede01STejun Heo * spin_lock_irq(gcwq->lock). 989bf4ede01STejun Heo */ 990b3f9f405SLai Jiangshan static void cwq_dec_nr_in_flight(struct cpu_workqueue_struct *cwq, int color) 991bf4ede01STejun Heo { 992bf4ede01STejun Heo /* ignore uncolored works */ 993bf4ede01STejun Heo if (color == WORK_NO_COLOR) 994bf4ede01STejun Heo return; 995bf4ede01STejun Heo 996bf4ede01STejun Heo cwq->nr_in_flight[color]--; 997bf4ede01STejun Heo 998bf4ede01STejun Heo cwq->nr_active--; 999bf4ede01STejun Heo if (!list_empty(&cwq->delayed_works)) { 1000bf4ede01STejun Heo /* one down, submit a delayed one */ 1001bf4ede01STejun Heo if (cwq->nr_active < cwq->max_active) 1002bf4ede01STejun Heo cwq_activate_first_delayed(cwq); 1003bf4ede01STejun Heo } 1004bf4ede01STejun Heo 1005bf4ede01STejun Heo /* is flush in progress and are we at the flushing tip? */ 1006bf4ede01STejun Heo if (likely(cwq->flush_color != color)) 1007bf4ede01STejun Heo return; 1008bf4ede01STejun Heo 1009bf4ede01STejun Heo /* are there still in-flight works? */ 1010bf4ede01STejun Heo if (cwq->nr_in_flight[color]) 1011bf4ede01STejun Heo return; 1012bf4ede01STejun Heo 1013bf4ede01STejun Heo /* this cwq is done, clear flush_color */ 1014bf4ede01STejun Heo cwq->flush_color = -1; 1015bf4ede01STejun Heo 1016bf4ede01STejun Heo /* 1017bf4ede01STejun Heo * If this was the last cwq, wake up the first flusher. It 1018bf4ede01STejun Heo * will handle the rest. 1019bf4ede01STejun Heo */ 1020bf4ede01STejun Heo if (atomic_dec_and_test(&cwq->wq->nr_cwqs_to_flush)) 1021bf4ede01STejun Heo complete(&cwq->wq->first_flusher->done); 1022bf4ede01STejun Heo } 1023bf4ede01STejun Heo 102436e227d2STejun Heo /** 1025bbb68dfaSTejun Heo * try_to_grab_pending - steal work item from worklist and disable irq 102636e227d2STejun Heo * @work: work item to steal 102736e227d2STejun Heo * @is_dwork: @work is a delayed_work 1028bbb68dfaSTejun Heo * @flags: place to store irq state 102936e227d2STejun Heo * 103036e227d2STejun Heo * Try to grab PENDING bit of @work. This function can handle @work in any 103136e227d2STejun Heo * stable state - idle, on timer or on worklist. Return values are 103236e227d2STejun Heo * 103336e227d2STejun Heo * 1 if @work was pending and we successfully stole PENDING 103436e227d2STejun Heo * 0 if @work was idle and we claimed PENDING 103536e227d2STejun Heo * -EAGAIN if PENDING couldn't be grabbed at the moment, safe to busy-retry 1036bbb68dfaSTejun Heo * -ENOENT if someone else is canceling @work, this state may persist 1037bbb68dfaSTejun Heo * for arbitrarily long 103836e227d2STejun Heo * 1039bbb68dfaSTejun Heo * On >= 0 return, the caller owns @work's PENDING bit. To avoid getting 1040e0aecdd8STejun Heo * interrupted while holding PENDING and @work off queue, irq must be 1041e0aecdd8STejun Heo * disabled on entry. This, combined with delayed_work->timer being 1042e0aecdd8STejun Heo * irqsafe, ensures that we return -EAGAIN for finite short period of time. 1043bbb68dfaSTejun Heo * 1044bbb68dfaSTejun Heo * On successful return, >= 0, irq is disabled and the caller is 1045bbb68dfaSTejun Heo * responsible for releasing it using local_irq_restore(*@flags). 1046bbb68dfaSTejun Heo * 1047e0aecdd8STejun Heo * This function is safe to call from any context including IRQ handler. 1048bf4ede01STejun Heo */ 1049bbb68dfaSTejun Heo static int try_to_grab_pending(struct work_struct *work, bool is_dwork, 1050bbb68dfaSTejun Heo unsigned long *flags) 1051bf4ede01STejun Heo { 1052bf4ede01STejun Heo struct global_cwq *gcwq; 1053bf4ede01STejun Heo 1054bbb68dfaSTejun Heo local_irq_save(*flags); 1055bbb68dfaSTejun Heo 105636e227d2STejun Heo /* try to steal the timer if it exists */ 105736e227d2STejun Heo if (is_dwork) { 105836e227d2STejun Heo struct delayed_work *dwork = to_delayed_work(work); 105936e227d2STejun Heo 1060e0aecdd8STejun Heo /* 1061e0aecdd8STejun Heo * dwork->timer is irqsafe. If del_timer() fails, it's 1062e0aecdd8STejun Heo * guaranteed that the timer is not queued anywhere and not 1063e0aecdd8STejun Heo * running on the local CPU. 1064e0aecdd8STejun Heo */ 106536e227d2STejun Heo if (likely(del_timer(&dwork->timer))) 106636e227d2STejun Heo return 1; 106736e227d2STejun Heo } 106836e227d2STejun Heo 106936e227d2STejun Heo /* try to claim PENDING the normal way */ 1070bf4ede01STejun Heo if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) 1071bf4ede01STejun Heo return 0; 1072bf4ede01STejun Heo 1073bf4ede01STejun Heo /* 1074bf4ede01STejun Heo * The queueing is in progress, or it is already queued. Try to 1075bf4ede01STejun Heo * steal it from ->worklist without clearing WORK_STRUCT_PENDING. 1076bf4ede01STejun Heo */ 1077bf4ede01STejun Heo gcwq = get_work_gcwq(work); 1078bf4ede01STejun Heo if (!gcwq) 1079bbb68dfaSTejun Heo goto fail; 1080bf4ede01STejun Heo 1081bbb68dfaSTejun Heo spin_lock(&gcwq->lock); 1082bf4ede01STejun Heo if (!list_empty(&work->entry)) { 1083bf4ede01STejun Heo /* 1084bf4ede01STejun Heo * This work is queued, but perhaps we locked the wrong gcwq. 1085bf4ede01STejun Heo * In that case we must see the new value after rmb(), see 1086bf4ede01STejun Heo * insert_work()->wmb(). 1087bf4ede01STejun Heo */ 1088bf4ede01STejun Heo smp_rmb(); 1089bf4ede01STejun Heo if (gcwq == get_work_gcwq(work)) { 1090bf4ede01STejun Heo debug_work_deactivate(work); 10913aa62497SLai Jiangshan 10923aa62497SLai Jiangshan /* 10933aa62497SLai Jiangshan * A delayed work item cannot be grabbed directly 10943aa62497SLai Jiangshan * because it might have linked NO_COLOR work items 10953aa62497SLai Jiangshan * which, if left on the delayed_list, will confuse 10963aa62497SLai Jiangshan * cwq->nr_active management later on and cause 10973aa62497SLai Jiangshan * stall. Make sure the work item is activated 10983aa62497SLai Jiangshan * before grabbing. 10993aa62497SLai Jiangshan */ 11003aa62497SLai Jiangshan if (*work_data_bits(work) & WORK_STRUCT_DELAYED) 11013aa62497SLai Jiangshan cwq_activate_delayed_work(work); 11023aa62497SLai Jiangshan 1103bf4ede01STejun Heo list_del_init(&work->entry); 1104bf4ede01STejun Heo cwq_dec_nr_in_flight(get_work_cwq(work), 1105b3f9f405SLai Jiangshan get_work_color(work)); 110636e227d2STejun Heo 1107bbb68dfaSTejun Heo spin_unlock(&gcwq->lock); 110836e227d2STejun Heo return 1; 1109bf4ede01STejun Heo } 1110bf4ede01STejun Heo } 1111bbb68dfaSTejun Heo spin_unlock(&gcwq->lock); 1112bbb68dfaSTejun Heo fail: 1113bbb68dfaSTejun Heo local_irq_restore(*flags); 1114bbb68dfaSTejun Heo if (work_is_canceling(work)) 1115bbb68dfaSTejun Heo return -ENOENT; 1116bbb68dfaSTejun Heo cpu_relax(); 111736e227d2STejun Heo return -EAGAIN; 1118bf4ede01STejun Heo } 1119bf4ede01STejun Heo 1120bf4ede01STejun Heo /** 11217e11629dSTejun Heo * insert_work - insert a work into gcwq 11224690c4abSTejun Heo * @cwq: cwq @work belongs to 11234690c4abSTejun Heo * @work: work to insert 11244690c4abSTejun Heo * @head: insertion point 11254690c4abSTejun Heo * @extra_flags: extra WORK_STRUCT_* flags to set 11264690c4abSTejun Heo * 11277e11629dSTejun Heo * Insert @work which belongs to @cwq into @gcwq after @head. 11287e11629dSTejun Heo * @extra_flags is or'd to work_struct flags. 11294690c4abSTejun Heo * 11304690c4abSTejun Heo * CONTEXT: 11318b03ae3cSTejun Heo * spin_lock_irq(gcwq->lock). 11321da177e4SLinus Torvalds */ 1133b89deed3SOleg Nesterov static void insert_work(struct cpu_workqueue_struct *cwq, 11344690c4abSTejun Heo struct work_struct *work, struct list_head *head, 11354690c4abSTejun Heo unsigned int extra_flags) 1136b89deed3SOleg Nesterov { 113763d95a91STejun Heo struct worker_pool *pool = cwq->pool; 1138e1d8aa9fSFrederic Weisbecker 11394690c4abSTejun Heo /* we own @work, set data and link */ 11407a22ad75STejun Heo set_work_cwq(work, cwq, extra_flags); 11414690c4abSTejun Heo 11426e84d644SOleg Nesterov /* 11436e84d644SOleg Nesterov * Ensure that we get the right work->data if we see the 11446e84d644SOleg Nesterov * result of list_add() below, see try_to_grab_pending(). 11456e84d644SOleg Nesterov */ 11466e84d644SOleg Nesterov smp_wmb(); 11474690c4abSTejun Heo 11481a4d9b0aSOleg Nesterov list_add_tail(&work->entry, head); 1149e22bee78STejun Heo 1150e22bee78STejun Heo /* 1151e22bee78STejun Heo * Ensure either worker_sched_deactivated() sees the above 1152e22bee78STejun Heo * list_add_tail() or we see zero nr_running to avoid workers 1153e22bee78STejun Heo * lying around lazily while there are works to be processed. 1154e22bee78STejun Heo */ 1155e22bee78STejun Heo smp_mb(); 1156e22bee78STejun Heo 115763d95a91STejun Heo if (__need_more_worker(pool)) 115863d95a91STejun Heo wake_up_worker(pool); 1159b89deed3SOleg Nesterov } 1160b89deed3SOleg Nesterov 1161c8efcc25STejun Heo /* 1162c8efcc25STejun Heo * Test whether @work is being queued from another work executing on the 1163c8efcc25STejun Heo * same workqueue. This is rather expensive and should only be used from 1164c8efcc25STejun Heo * cold paths. 1165c8efcc25STejun Heo */ 1166c8efcc25STejun Heo static bool is_chained_work(struct workqueue_struct *wq) 1167c8efcc25STejun Heo { 1168c8efcc25STejun Heo unsigned long flags; 1169c8efcc25STejun Heo unsigned int cpu; 1170c8efcc25STejun Heo 1171c8efcc25STejun Heo for_each_gcwq_cpu(cpu) { 1172c8efcc25STejun Heo struct global_cwq *gcwq = get_gcwq(cpu); 1173c8efcc25STejun Heo struct worker *worker; 1174c8efcc25STejun Heo struct hlist_node *pos; 1175c8efcc25STejun Heo int i; 1176c8efcc25STejun Heo 1177c8efcc25STejun Heo spin_lock_irqsave(&gcwq->lock, flags); 1178c8efcc25STejun Heo for_each_busy_worker(worker, i, pos, gcwq) { 1179c8efcc25STejun Heo if (worker->task != current) 1180c8efcc25STejun Heo continue; 1181c8efcc25STejun Heo spin_unlock_irqrestore(&gcwq->lock, flags); 1182c8efcc25STejun Heo /* 1183c8efcc25STejun Heo * I'm @worker, no locking necessary. See if @work 1184c8efcc25STejun Heo * is headed to the same workqueue. 1185c8efcc25STejun Heo */ 1186c8efcc25STejun Heo return worker->current_cwq->wq == wq; 1187c8efcc25STejun Heo } 1188c8efcc25STejun Heo spin_unlock_irqrestore(&gcwq->lock, flags); 1189c8efcc25STejun Heo } 1190c8efcc25STejun Heo return false; 1191c8efcc25STejun Heo } 1192c8efcc25STejun Heo 11934690c4abSTejun Heo static void __queue_work(unsigned int cpu, struct workqueue_struct *wq, 11941da177e4SLinus Torvalds struct work_struct *work) 11951da177e4SLinus Torvalds { 1196502ca9d8STejun Heo struct global_cwq *gcwq; 1197502ca9d8STejun Heo struct cpu_workqueue_struct *cwq; 11981e19ffc6STejun Heo struct list_head *worklist; 11998a2e8e5dSTejun Heo unsigned int work_flags; 1200b75cac93SJoonsoo Kim unsigned int req_cpu = cpu; 12018930cabaSTejun Heo 12028930cabaSTejun Heo /* 12038930cabaSTejun Heo * While a work item is PENDING && off queue, a task trying to 12048930cabaSTejun Heo * steal the PENDING will busy-loop waiting for it to either get 12058930cabaSTejun Heo * queued or lose PENDING. Grabbing PENDING and queueing should 12068930cabaSTejun Heo * happen with IRQ disabled. 12078930cabaSTejun Heo */ 12088930cabaSTejun Heo WARN_ON_ONCE(!irqs_disabled()); 12091da177e4SLinus Torvalds 1210dc186ad7SThomas Gleixner debug_work_activate(work); 12111e19ffc6STejun Heo 1212c8efcc25STejun Heo /* if dying, only works from the same workqueue are allowed */ 12139c5a2ba7STejun Heo if (unlikely(wq->flags & WQ_DRAINING) && 1214c8efcc25STejun Heo WARN_ON_ONCE(!is_chained_work(wq))) 1215e41e704bSTejun Heo return; 1216e41e704bSTejun Heo 1217c7fc77f7STejun Heo /* determine gcwq to use */ 1218c7fc77f7STejun Heo if (!(wq->flags & WQ_UNBOUND)) { 1219c7fc77f7STejun Heo struct global_cwq *last_gcwq; 1220c7fc77f7STejun Heo 122157469821STejun Heo if (cpu == WORK_CPU_UNBOUND) 1222f3421797STejun Heo cpu = raw_smp_processor_id(); 1223f3421797STejun Heo 122418aa9effSTejun Heo /* 1225dbf2576eSTejun Heo * It's multi cpu. If @work was previously on a different 1226dbf2576eSTejun Heo * cpu, it might still be running there, in which case the 1227dbf2576eSTejun Heo * work needs to be queued on that cpu to guarantee 1228dbf2576eSTejun Heo * non-reentrancy. 122918aa9effSTejun Heo */ 1230502ca9d8STejun Heo gcwq = get_gcwq(cpu); 1231dbf2576eSTejun Heo last_gcwq = get_work_gcwq(work); 1232dbf2576eSTejun Heo 1233dbf2576eSTejun Heo if (last_gcwq && last_gcwq != gcwq) { 123418aa9effSTejun Heo struct worker *worker; 123518aa9effSTejun Heo 12368930cabaSTejun Heo spin_lock(&last_gcwq->lock); 123718aa9effSTejun Heo 123818aa9effSTejun Heo worker = find_worker_executing_work(last_gcwq, work); 123918aa9effSTejun Heo 124018aa9effSTejun Heo if (worker && worker->current_cwq->wq == wq) 124118aa9effSTejun Heo gcwq = last_gcwq; 124218aa9effSTejun Heo else { 124318aa9effSTejun Heo /* meh... not running there, queue here */ 12448930cabaSTejun Heo spin_unlock(&last_gcwq->lock); 12458930cabaSTejun Heo spin_lock(&gcwq->lock); 124618aa9effSTejun Heo } 12478930cabaSTejun Heo } else { 12488930cabaSTejun Heo spin_lock(&gcwq->lock); 12498930cabaSTejun Heo } 1250f3421797STejun Heo } else { 1251f3421797STejun Heo gcwq = get_gcwq(WORK_CPU_UNBOUND); 12528930cabaSTejun Heo spin_lock(&gcwq->lock); 1253502ca9d8STejun Heo } 1254502ca9d8STejun Heo 1255502ca9d8STejun Heo /* gcwq determined, get cwq and queue */ 1256502ca9d8STejun Heo cwq = get_cwq(gcwq->cpu, wq); 1257b75cac93SJoonsoo Kim trace_workqueue_queue_work(req_cpu, cwq, work); 1258502ca9d8STejun Heo 1259f5b2552bSDan Carpenter if (WARN_ON(!list_empty(&work->entry))) { 12608930cabaSTejun Heo spin_unlock(&gcwq->lock); 1261f5b2552bSDan Carpenter return; 1262f5b2552bSDan Carpenter } 12631e19ffc6STejun Heo 126473f53c4aSTejun Heo cwq->nr_in_flight[cwq->work_color]++; 12658a2e8e5dSTejun Heo work_flags = work_color_to_flags(cwq->work_color); 12661e19ffc6STejun Heo 12671e19ffc6STejun Heo if (likely(cwq->nr_active < cwq->max_active)) { 1268cdadf009STejun Heo trace_workqueue_activate_work(work); 12691e19ffc6STejun Heo cwq->nr_active++; 12703270476aSTejun Heo worklist = &cwq->pool->worklist; 12718a2e8e5dSTejun Heo } else { 12728a2e8e5dSTejun Heo work_flags |= WORK_STRUCT_DELAYED; 12731e19ffc6STejun Heo worklist = &cwq->delayed_works; 12748a2e8e5dSTejun Heo } 12751e19ffc6STejun Heo 12768a2e8e5dSTejun Heo insert_work(cwq, work, worklist, work_flags); 12771e19ffc6STejun Heo 12788930cabaSTejun Heo spin_unlock(&gcwq->lock); 12791da177e4SLinus Torvalds } 12801da177e4SLinus Torvalds 12810fcb78c2SRolf Eike Beer /** 1282c1a220e7SZhang Rui * queue_work_on - queue work on specific cpu 1283c1a220e7SZhang Rui * @cpu: CPU number to execute work on 1284c1a220e7SZhang Rui * @wq: workqueue to use 1285c1a220e7SZhang Rui * @work: work to queue 1286c1a220e7SZhang Rui * 1287d4283e93STejun Heo * Returns %false if @work was already on a queue, %true otherwise. 1288c1a220e7SZhang Rui * 1289c1a220e7SZhang Rui * We queue the work to a specific CPU, the caller must ensure it 1290c1a220e7SZhang Rui * can't go away. 1291c1a220e7SZhang Rui */ 1292d4283e93STejun Heo bool queue_work_on(int cpu, struct workqueue_struct *wq, 1293d4283e93STejun Heo struct work_struct *work) 1294c1a220e7SZhang Rui { 1295d4283e93STejun Heo bool ret = false; 12968930cabaSTejun Heo unsigned long flags; 12978930cabaSTejun Heo 12988930cabaSTejun Heo local_irq_save(flags); 1299c1a220e7SZhang Rui 130022df02bbSTejun Heo if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) { 13014690c4abSTejun Heo __queue_work(cpu, wq, work); 1302d4283e93STejun Heo ret = true; 1303c1a220e7SZhang Rui } 13048930cabaSTejun Heo 13058930cabaSTejun Heo local_irq_restore(flags); 1306c1a220e7SZhang Rui return ret; 1307c1a220e7SZhang Rui } 1308c1a220e7SZhang Rui EXPORT_SYMBOL_GPL(queue_work_on); 1309c1a220e7SZhang Rui 13100a13c00eSTejun Heo /** 13110a13c00eSTejun Heo * queue_work - queue work on a workqueue 13120a13c00eSTejun Heo * @wq: workqueue to use 13130a13c00eSTejun Heo * @work: work to queue 13140a13c00eSTejun Heo * 1315d4283e93STejun Heo * Returns %false if @work was already on a queue, %true otherwise. 13160a13c00eSTejun Heo * 13170a13c00eSTejun Heo * We queue the work to the CPU on which it was submitted, but if the CPU dies 13180a13c00eSTejun Heo * it can be processed by another CPU. 13190a13c00eSTejun Heo */ 1320d4283e93STejun Heo bool queue_work(struct workqueue_struct *wq, struct work_struct *work) 13210a13c00eSTejun Heo { 132257469821STejun Heo return queue_work_on(WORK_CPU_UNBOUND, wq, work); 13230a13c00eSTejun Heo } 13240a13c00eSTejun Heo EXPORT_SYMBOL_GPL(queue_work); 13250a13c00eSTejun Heo 1326d8e794dfSTejun Heo void delayed_work_timer_fn(unsigned long __data) 13271da177e4SLinus Torvalds { 132852bad64dSDavid Howells struct delayed_work *dwork = (struct delayed_work *)__data; 13297a22ad75STejun Heo struct cpu_workqueue_struct *cwq = get_work_cwq(&dwork->work); 13301da177e4SLinus Torvalds 1331e0aecdd8STejun Heo /* should have been called from irqsafe timer with irq already off */ 13321265057fSTejun Heo __queue_work(dwork->cpu, cwq->wq, &dwork->work); 13331da177e4SLinus Torvalds } 1334d8e794dfSTejun Heo EXPORT_SYMBOL_GPL(delayed_work_timer_fn); 13351da177e4SLinus Torvalds 13367beb2edfSTejun Heo static void __queue_delayed_work(int cpu, struct workqueue_struct *wq, 133752bad64dSDavid Howells struct delayed_work *dwork, unsigned long delay) 13381da177e4SLinus Torvalds { 13397beb2edfSTejun Heo struct timer_list *timer = &dwork->timer; 13407beb2edfSTejun Heo struct work_struct *work = &dwork->work; 13417beb2edfSTejun Heo unsigned int lcpu; 13421da177e4SLinus Torvalds 13437beb2edfSTejun Heo WARN_ON_ONCE(timer->function != delayed_work_timer_fn || 13447beb2edfSTejun Heo timer->data != (unsigned long)dwork); 1345fc4b514fSTejun Heo WARN_ON_ONCE(timer_pending(timer)); 1346fc4b514fSTejun Heo WARN_ON_ONCE(!list_empty(&work->entry)); 13477beb2edfSTejun Heo 13488852aac2STejun Heo /* 13498852aac2STejun Heo * If @delay is 0, queue @dwork->work immediately. This is for 13508852aac2STejun Heo * both optimization and correctness. The earliest @timer can 13518852aac2STejun Heo * expire is on the closest next tick and delayed_work users depend 13528852aac2STejun Heo * on that there's no such delay when @delay is 0. 13538852aac2STejun Heo */ 13548852aac2STejun Heo if (!delay) { 13558852aac2STejun Heo __queue_work(cpu, wq, &dwork->work); 13568852aac2STejun Heo return; 13578852aac2STejun Heo } 13588852aac2STejun Heo 13597beb2edfSTejun Heo timer_stats_timer_set_start_info(&dwork->timer); 13607beb2edfSTejun Heo 13617beb2edfSTejun Heo /* 13627beb2edfSTejun Heo * This stores cwq for the moment, for the timer_fn. Note that the 13637beb2edfSTejun Heo * work's gcwq is preserved to allow reentrance detection for 13647beb2edfSTejun Heo * delayed works. 13657beb2edfSTejun Heo */ 13667beb2edfSTejun Heo if (!(wq->flags & WQ_UNBOUND)) { 13677beb2edfSTejun Heo struct global_cwq *gcwq = get_work_gcwq(work); 13687beb2edfSTejun Heo 1369e42986deSJoonsoo Kim /* 1370e42986deSJoonsoo Kim * If we cannot get the last gcwq from @work directly, 1371e42986deSJoonsoo Kim * select the last CPU such that it avoids unnecessarily 1372e42986deSJoonsoo Kim * triggering non-reentrancy check in __queue_work(). 1373e42986deSJoonsoo Kim */ 1374e42986deSJoonsoo Kim lcpu = cpu; 1375e42986deSJoonsoo Kim if (gcwq) 13767beb2edfSTejun Heo lcpu = gcwq->cpu; 1377e42986deSJoonsoo Kim if (lcpu == WORK_CPU_UNBOUND) 13787beb2edfSTejun Heo lcpu = raw_smp_processor_id(); 13797beb2edfSTejun Heo } else { 13807beb2edfSTejun Heo lcpu = WORK_CPU_UNBOUND; 13811da177e4SLinus Torvalds } 13827beb2edfSTejun Heo 13837beb2edfSTejun Heo set_work_cwq(work, get_cwq(lcpu, wq), 0); 13847beb2edfSTejun Heo 13851265057fSTejun Heo dwork->cpu = cpu; 13867beb2edfSTejun Heo timer->expires = jiffies + delay; 13877beb2edfSTejun Heo 13887beb2edfSTejun Heo if (unlikely(cpu != WORK_CPU_UNBOUND)) 13897beb2edfSTejun Heo add_timer_on(timer, cpu); 13907beb2edfSTejun Heo else 13917beb2edfSTejun Heo add_timer(timer); 13927beb2edfSTejun Heo } 13931da177e4SLinus Torvalds 13940fcb78c2SRolf Eike Beer /** 13950fcb78c2SRolf Eike Beer * queue_delayed_work_on - queue work on specific CPU after delay 13960fcb78c2SRolf Eike Beer * @cpu: CPU number to execute work on 13970fcb78c2SRolf Eike Beer * @wq: workqueue to use 1398af9997e4SRandy Dunlap * @dwork: work to queue 13990fcb78c2SRolf Eike Beer * @delay: number of jiffies to wait before queueing 14000fcb78c2SRolf Eike Beer * 1401715f1300STejun Heo * Returns %false if @work was already on a queue, %true otherwise. If 1402715f1300STejun Heo * @delay is zero and @dwork is idle, it will be scheduled for immediate 1403715f1300STejun Heo * execution. 14040fcb78c2SRolf Eike Beer */ 1405d4283e93STejun Heo bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq, 140652bad64dSDavid Howells struct delayed_work *dwork, unsigned long delay) 14077a6bc1cdSVenkatesh Pallipadi { 140852bad64dSDavid Howells struct work_struct *work = &dwork->work; 1409d4283e93STejun Heo bool ret = false; 14108930cabaSTejun Heo unsigned long flags; 14118930cabaSTejun Heo 14128930cabaSTejun Heo /* read the comment in __queue_work() */ 14138930cabaSTejun Heo local_irq_save(flags); 14147a6bc1cdSVenkatesh Pallipadi 141522df02bbSTejun Heo if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) { 14167beb2edfSTejun Heo __queue_delayed_work(cpu, wq, dwork, delay); 1417d4283e93STejun Heo ret = true; 14187a6bc1cdSVenkatesh Pallipadi } 14198930cabaSTejun Heo 14208930cabaSTejun Heo local_irq_restore(flags); 14217a6bc1cdSVenkatesh Pallipadi return ret; 14227a6bc1cdSVenkatesh Pallipadi } 1423ae90dd5dSDave Jones EXPORT_SYMBOL_GPL(queue_delayed_work_on); 14241da177e4SLinus Torvalds 1425c8e55f36STejun Heo /** 14260a13c00eSTejun Heo * queue_delayed_work - queue work on a workqueue after delay 14270a13c00eSTejun Heo * @wq: workqueue to use 14280a13c00eSTejun Heo * @dwork: delayable work to queue 14290a13c00eSTejun Heo * @delay: number of jiffies to wait before queueing 14300a13c00eSTejun Heo * 1431715f1300STejun Heo * Equivalent to queue_delayed_work_on() but tries to use the local CPU. 14320a13c00eSTejun Heo */ 1433d4283e93STejun Heo bool queue_delayed_work(struct workqueue_struct *wq, 14340a13c00eSTejun Heo struct delayed_work *dwork, unsigned long delay) 14350a13c00eSTejun Heo { 143657469821STejun Heo return queue_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay); 14370a13c00eSTejun Heo } 14380a13c00eSTejun Heo EXPORT_SYMBOL_GPL(queue_delayed_work); 14390a13c00eSTejun Heo 14400a13c00eSTejun Heo /** 14418376fe22STejun Heo * mod_delayed_work_on - modify delay of or queue a delayed work on specific CPU 14428376fe22STejun Heo * @cpu: CPU number to execute work on 14438376fe22STejun Heo * @wq: workqueue to use 14448376fe22STejun Heo * @dwork: work to queue 14458376fe22STejun Heo * @delay: number of jiffies to wait before queueing 14468376fe22STejun Heo * 14478376fe22STejun Heo * If @dwork is idle, equivalent to queue_delayed_work_on(); otherwise, 14488376fe22STejun Heo * modify @dwork's timer so that it expires after @delay. If @delay is 14498376fe22STejun Heo * zero, @work is guaranteed to be scheduled immediately regardless of its 14508376fe22STejun Heo * current state. 14518376fe22STejun Heo * 14528376fe22STejun Heo * Returns %false if @dwork was idle and queued, %true if @dwork was 14538376fe22STejun Heo * pending and its timer was modified. 14548376fe22STejun Heo * 1455e0aecdd8STejun Heo * This function is safe to call from any context including IRQ handler. 14568376fe22STejun Heo * See try_to_grab_pending() for details. 14578376fe22STejun Heo */ 14588376fe22STejun Heo bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq, 14598376fe22STejun Heo struct delayed_work *dwork, unsigned long delay) 14608376fe22STejun Heo { 14618376fe22STejun Heo unsigned long flags; 14628376fe22STejun Heo int ret; 14638376fe22STejun Heo 14648376fe22STejun Heo do { 14658376fe22STejun Heo ret = try_to_grab_pending(&dwork->work, true, &flags); 14668376fe22STejun Heo } while (unlikely(ret == -EAGAIN)); 14678376fe22STejun Heo 14688376fe22STejun Heo if (likely(ret >= 0)) { 14698376fe22STejun Heo __queue_delayed_work(cpu, wq, dwork, delay); 14708376fe22STejun Heo local_irq_restore(flags); 14718376fe22STejun Heo } 14728376fe22STejun Heo 14738376fe22STejun Heo /* -ENOENT from try_to_grab_pending() becomes %true */ 14748376fe22STejun Heo return ret; 14758376fe22STejun Heo } 14768376fe22STejun Heo EXPORT_SYMBOL_GPL(mod_delayed_work_on); 14778376fe22STejun Heo 14788376fe22STejun Heo /** 14798376fe22STejun Heo * mod_delayed_work - modify delay of or queue a delayed work 14808376fe22STejun Heo * @wq: workqueue to use 14818376fe22STejun Heo * @dwork: work to queue 14828376fe22STejun Heo * @delay: number of jiffies to wait before queueing 14838376fe22STejun Heo * 14848376fe22STejun Heo * mod_delayed_work_on() on local CPU. 14858376fe22STejun Heo */ 14868376fe22STejun Heo bool mod_delayed_work(struct workqueue_struct *wq, struct delayed_work *dwork, 14878376fe22STejun Heo unsigned long delay) 14888376fe22STejun Heo { 14898376fe22STejun Heo return mod_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay); 14908376fe22STejun Heo } 14918376fe22STejun Heo EXPORT_SYMBOL_GPL(mod_delayed_work); 14928376fe22STejun Heo 14938376fe22STejun Heo /** 1494c8e55f36STejun Heo * worker_enter_idle - enter idle state 1495c8e55f36STejun Heo * @worker: worker which is entering idle state 1496c8e55f36STejun Heo * 1497c8e55f36STejun Heo * @worker is entering idle state. Update stats and idle timer if 1498c8e55f36STejun Heo * necessary. 1499c8e55f36STejun Heo * 1500c8e55f36STejun Heo * LOCKING: 1501c8e55f36STejun Heo * spin_lock_irq(gcwq->lock). 1502c8e55f36STejun Heo */ 1503c8e55f36STejun Heo static void worker_enter_idle(struct worker *worker) 15041da177e4SLinus Torvalds { 1505bd7bdd43STejun Heo struct worker_pool *pool = worker->pool; 1506bd7bdd43STejun Heo struct global_cwq *gcwq = pool->gcwq; 1507c8e55f36STejun Heo 1508c8e55f36STejun Heo BUG_ON(worker->flags & WORKER_IDLE); 1509c8e55f36STejun Heo BUG_ON(!list_empty(&worker->entry) && 1510c8e55f36STejun Heo (worker->hentry.next || worker->hentry.pprev)); 1511c8e55f36STejun Heo 1512cb444766STejun Heo /* can't use worker_set_flags(), also called from start_worker() */ 1513cb444766STejun Heo worker->flags |= WORKER_IDLE; 1514bd7bdd43STejun Heo pool->nr_idle++; 1515e22bee78STejun Heo worker->last_active = jiffies; 1516c8e55f36STejun Heo 1517c8e55f36STejun Heo /* idle_list is LIFO */ 1518bd7bdd43STejun Heo list_add(&worker->entry, &pool->idle_list); 1519db7bccf4STejun Heo 152063d95a91STejun Heo if (too_many_workers(pool) && !timer_pending(&pool->idle_timer)) 1521628c78e7STejun Heo mod_timer(&pool->idle_timer, jiffies + IDLE_WORKER_TIMEOUT); 1522cb444766STejun Heo 1523544ecf31STejun Heo /* 1524628c78e7STejun Heo * Sanity check nr_running. Because gcwq_unbind_fn() releases 1525628c78e7STejun Heo * gcwq->lock between setting %WORKER_UNBOUND and zapping 1526628c78e7STejun Heo * nr_running, the warning may trigger spuriously. Check iff 1527628c78e7STejun Heo * unbind is not in progress. 1528544ecf31STejun Heo */ 1529628c78e7STejun Heo WARN_ON_ONCE(!(gcwq->flags & GCWQ_DISASSOCIATED) && 1530bd7bdd43STejun Heo pool->nr_workers == pool->nr_idle && 153163d95a91STejun Heo atomic_read(get_pool_nr_running(pool))); 1532c8e55f36STejun Heo } 1533c8e55f36STejun Heo 1534c8e55f36STejun Heo /** 1535c8e55f36STejun Heo * worker_leave_idle - leave idle state 1536c8e55f36STejun Heo * @worker: worker which is leaving idle state 1537c8e55f36STejun Heo * 1538c8e55f36STejun Heo * @worker is leaving idle state. Update stats. 1539c8e55f36STejun Heo * 1540c8e55f36STejun Heo * LOCKING: 1541c8e55f36STejun Heo * spin_lock_irq(gcwq->lock). 1542c8e55f36STejun Heo */ 1543c8e55f36STejun Heo static void worker_leave_idle(struct worker *worker) 1544c8e55f36STejun Heo { 1545bd7bdd43STejun Heo struct worker_pool *pool = worker->pool; 1546c8e55f36STejun Heo 1547c8e55f36STejun Heo BUG_ON(!(worker->flags & WORKER_IDLE)); 1548d302f017STejun Heo worker_clr_flags(worker, WORKER_IDLE); 1549bd7bdd43STejun Heo pool->nr_idle--; 1550c8e55f36STejun Heo list_del_init(&worker->entry); 1551c8e55f36STejun Heo } 1552c8e55f36STejun Heo 1553e22bee78STejun Heo /** 1554e22bee78STejun Heo * worker_maybe_bind_and_lock - bind worker to its cpu if possible and lock gcwq 1555e22bee78STejun Heo * @worker: self 1556e22bee78STejun Heo * 1557e22bee78STejun Heo * Works which are scheduled while the cpu is online must at least be 1558e22bee78STejun Heo * scheduled to a worker which is bound to the cpu so that if they are 1559e22bee78STejun Heo * flushed from cpu callbacks while cpu is going down, they are 1560e22bee78STejun Heo * guaranteed to execute on the cpu. 1561e22bee78STejun Heo * 1562e22bee78STejun Heo * This function is to be used by rogue workers and rescuers to bind 1563e22bee78STejun Heo * themselves to the target cpu and may race with cpu going down or 1564e22bee78STejun Heo * coming online. kthread_bind() can't be used because it may put the 1565e22bee78STejun Heo * worker to already dead cpu and set_cpus_allowed_ptr() can't be used 1566e22bee78STejun Heo * verbatim as it's best effort and blocking and gcwq may be 1567e22bee78STejun Heo * [dis]associated in the meantime. 1568e22bee78STejun Heo * 1569f2d5a0eeSTejun Heo * This function tries set_cpus_allowed() and locks gcwq and verifies the 1570f2d5a0eeSTejun Heo * binding against %GCWQ_DISASSOCIATED which is set during 1571f2d5a0eeSTejun Heo * %CPU_DOWN_PREPARE and cleared during %CPU_ONLINE, so if the worker 1572f2d5a0eeSTejun Heo * enters idle state or fetches works without dropping lock, it can 1573f2d5a0eeSTejun Heo * guarantee the scheduling requirement described in the first paragraph. 1574e22bee78STejun Heo * 1575e22bee78STejun Heo * CONTEXT: 1576e22bee78STejun Heo * Might sleep. Called without any lock but returns with gcwq->lock 1577e22bee78STejun Heo * held. 1578e22bee78STejun Heo * 1579e22bee78STejun Heo * RETURNS: 1580e22bee78STejun Heo * %true if the associated gcwq is online (@worker is successfully 1581e22bee78STejun Heo * bound), %false if offline. 1582e22bee78STejun Heo */ 1583e22bee78STejun Heo static bool worker_maybe_bind_and_lock(struct worker *worker) 1584972fa1c5SNamhyung Kim __acquires(&gcwq->lock) 1585e22bee78STejun Heo { 1586bd7bdd43STejun Heo struct global_cwq *gcwq = worker->pool->gcwq; 1587e22bee78STejun Heo struct task_struct *task = worker->task; 1588e22bee78STejun Heo 1589e22bee78STejun Heo while (true) { 1590e22bee78STejun Heo /* 1591e22bee78STejun Heo * The following call may fail, succeed or succeed 1592e22bee78STejun Heo * without actually migrating the task to the cpu if 1593e22bee78STejun Heo * it races with cpu hotunplug operation. Verify 1594e22bee78STejun Heo * against GCWQ_DISASSOCIATED. 1595e22bee78STejun Heo */ 1596f3421797STejun Heo if (!(gcwq->flags & GCWQ_DISASSOCIATED)) 1597e22bee78STejun Heo set_cpus_allowed_ptr(task, get_cpu_mask(gcwq->cpu)); 1598e22bee78STejun Heo 1599e22bee78STejun Heo spin_lock_irq(&gcwq->lock); 1600e22bee78STejun Heo if (gcwq->flags & GCWQ_DISASSOCIATED) 1601e22bee78STejun Heo return false; 1602e22bee78STejun Heo if (task_cpu(task) == gcwq->cpu && 1603e22bee78STejun Heo cpumask_equal(¤t->cpus_allowed, 1604e22bee78STejun Heo get_cpu_mask(gcwq->cpu))) 1605e22bee78STejun Heo return true; 1606e22bee78STejun Heo spin_unlock_irq(&gcwq->lock); 1607e22bee78STejun Heo 16085035b20fSTejun Heo /* 16095035b20fSTejun Heo * We've raced with CPU hot[un]plug. Give it a breather 16105035b20fSTejun Heo * and retry migration. cond_resched() is required here; 16115035b20fSTejun Heo * otherwise, we might deadlock against cpu_stop trying to 16125035b20fSTejun Heo * bring down the CPU on non-preemptive kernel. 16135035b20fSTejun Heo */ 1614e22bee78STejun Heo cpu_relax(); 16155035b20fSTejun Heo cond_resched(); 1616e22bee78STejun Heo } 1617e22bee78STejun Heo } 1618e22bee78STejun Heo 1619e22bee78STejun Heo /* 1620ea1abd61SLai Jiangshan * Rebind an idle @worker to its CPU. worker_thread() will test 16215f7dabfdSLai Jiangshan * list_empty(@worker->entry) before leaving idle and call this function. 162225511a47STejun Heo */ 162325511a47STejun Heo static void idle_worker_rebind(struct worker *worker) 162425511a47STejun Heo { 162525511a47STejun Heo struct global_cwq *gcwq = worker->pool->gcwq; 162625511a47STejun Heo 16275f7dabfdSLai Jiangshan /* CPU may go down again inbetween, clear UNBOUND only on success */ 16285f7dabfdSLai Jiangshan if (worker_maybe_bind_and_lock(worker)) 16295f7dabfdSLai Jiangshan worker_clr_flags(worker, WORKER_UNBOUND); 163025511a47STejun Heo 1631ea1abd61SLai Jiangshan /* rebind complete, become available again */ 1632ea1abd61SLai Jiangshan list_add(&worker->entry, &worker->pool->idle_list); 1633ea1abd61SLai Jiangshan spin_unlock_irq(&gcwq->lock); 163425511a47STejun Heo } 163525511a47STejun Heo 163625511a47STejun Heo /* 163725511a47STejun Heo * Function for @worker->rebind.work used to rebind unbound busy workers to 1638403c821dSTejun Heo * the associated cpu which is coming back online. This is scheduled by 1639403c821dSTejun Heo * cpu up but can race with other cpu hotplug operations and may be 1640403c821dSTejun Heo * executed twice without intervening cpu down. 1641e22bee78STejun Heo */ 164225511a47STejun Heo static void busy_worker_rebind_fn(struct work_struct *work) 1643e22bee78STejun Heo { 1644e22bee78STejun Heo struct worker *worker = container_of(work, struct worker, rebind_work); 1645bd7bdd43STejun Heo struct global_cwq *gcwq = worker->pool->gcwq; 1646e22bee78STejun Heo 1647eab6d828SLai Jiangshan if (worker_maybe_bind_and_lock(worker)) 1648eab6d828SLai Jiangshan worker_clr_flags(worker, WORKER_UNBOUND); 1649e22bee78STejun Heo 1650e22bee78STejun Heo spin_unlock_irq(&gcwq->lock); 1651e22bee78STejun Heo } 1652e22bee78STejun Heo 165325511a47STejun Heo /** 165425511a47STejun Heo * rebind_workers - rebind all workers of a gcwq to the associated CPU 165525511a47STejun Heo * @gcwq: gcwq of interest 165625511a47STejun Heo * 165725511a47STejun Heo * @gcwq->cpu is coming online. Rebind all workers to the CPU. Rebinding 165825511a47STejun Heo * is different for idle and busy ones. 165925511a47STejun Heo * 1660ea1abd61SLai Jiangshan * Idle ones will be removed from the idle_list and woken up. They will 1661ea1abd61SLai Jiangshan * add themselves back after completing rebind. This ensures that the 1662ea1abd61SLai Jiangshan * idle_list doesn't contain any unbound workers when re-bound busy workers 1663ea1abd61SLai Jiangshan * try to perform local wake-ups for concurrency management. 166425511a47STejun Heo * 1665ea1abd61SLai Jiangshan * Busy workers can rebind after they finish their current work items. 1666ea1abd61SLai Jiangshan * Queueing the rebind work item at the head of the scheduled list is 1667ea1abd61SLai Jiangshan * enough. Note that nr_running will be properly bumped as busy workers 1668ea1abd61SLai Jiangshan * rebind. 166925511a47STejun Heo * 1670ea1abd61SLai Jiangshan * On return, all non-manager workers are scheduled for rebind - see 1671ea1abd61SLai Jiangshan * manage_workers() for the manager special case. Any idle worker 1672ea1abd61SLai Jiangshan * including the manager will not appear on @idle_list until rebind is 1673ea1abd61SLai Jiangshan * complete, making local wake-ups safe. 167425511a47STejun Heo */ 167525511a47STejun Heo static void rebind_workers(struct global_cwq *gcwq) 167625511a47STejun Heo { 167725511a47STejun Heo struct worker_pool *pool; 1678ea1abd61SLai Jiangshan struct worker *worker, *n; 167925511a47STejun Heo struct hlist_node *pos; 168025511a47STejun Heo int i; 168125511a47STejun Heo 168225511a47STejun Heo lockdep_assert_held(&gcwq->lock); 168325511a47STejun Heo 168425511a47STejun Heo for_each_worker_pool(pool, gcwq) 1685b2eb83d1SLai Jiangshan lockdep_assert_held(&pool->assoc_mutex); 168625511a47STejun Heo 16875f7dabfdSLai Jiangshan /* dequeue and kick idle ones */ 168825511a47STejun Heo for_each_worker_pool(pool, gcwq) { 1689ea1abd61SLai Jiangshan list_for_each_entry_safe(worker, n, &pool->idle_list, entry) { 1690ea1abd61SLai Jiangshan /* 1691ea1abd61SLai Jiangshan * idle workers should be off @pool->idle_list 1692ea1abd61SLai Jiangshan * until rebind is complete to avoid receiving 1693ea1abd61SLai Jiangshan * premature local wake-ups. 1694ea1abd61SLai Jiangshan */ 1695ea1abd61SLai Jiangshan list_del_init(&worker->entry); 169625511a47STejun Heo 169725511a47STejun Heo /* 16985f7dabfdSLai Jiangshan * worker_thread() will see the above dequeuing 16995f7dabfdSLai Jiangshan * and call idle_worker_rebind(). 170025511a47STejun Heo */ 170125511a47STejun Heo wake_up_process(worker->task); 170225511a47STejun Heo } 170325511a47STejun Heo } 170425511a47STejun Heo 1705ea1abd61SLai Jiangshan /* rebind busy workers */ 170625511a47STejun Heo for_each_busy_worker(worker, i, pos, gcwq) { 170725511a47STejun Heo struct work_struct *rebind_work = &worker->rebind_work; 1708e2b6a6d5SJoonsoo Kim struct workqueue_struct *wq; 170925511a47STejun Heo 171025511a47STejun Heo if (test_and_set_bit(WORK_STRUCT_PENDING_BIT, 171125511a47STejun Heo work_data_bits(rebind_work))) 171225511a47STejun Heo continue; 171325511a47STejun Heo 171425511a47STejun Heo debug_work_activate(rebind_work); 171590beca5dSTejun Heo 171690beca5dSTejun Heo /* 1717e2b6a6d5SJoonsoo Kim * wq doesn't really matter but let's keep @worker->pool 1718e2b6a6d5SJoonsoo Kim * and @cwq->pool consistent for sanity. 171990beca5dSTejun Heo */ 1720e2b6a6d5SJoonsoo Kim if (worker_pool_pri(worker->pool)) 1721e2b6a6d5SJoonsoo Kim wq = system_highpri_wq; 1722e2b6a6d5SJoonsoo Kim else 1723e2b6a6d5SJoonsoo Kim wq = system_wq; 1724ec58815aSTejun Heo 1725e2b6a6d5SJoonsoo Kim insert_work(get_cwq(gcwq->cpu, wq), rebind_work, 172625511a47STejun Heo worker->scheduled.next, 172725511a47STejun Heo work_color_to_flags(WORK_NO_COLOR)); 1728ec58815aSTejun Heo } 172925511a47STejun Heo } 173025511a47STejun Heo 1731c34056a3STejun Heo static struct worker *alloc_worker(void) 1732c34056a3STejun Heo { 1733c34056a3STejun Heo struct worker *worker; 1734c34056a3STejun Heo 1735c34056a3STejun Heo worker = kzalloc(sizeof(*worker), GFP_KERNEL); 1736c8e55f36STejun Heo if (worker) { 1737c8e55f36STejun Heo INIT_LIST_HEAD(&worker->entry); 1738affee4b2STejun Heo INIT_LIST_HEAD(&worker->scheduled); 173925511a47STejun Heo INIT_WORK(&worker->rebind_work, busy_worker_rebind_fn); 1740e22bee78STejun Heo /* on creation a worker is in !idle && prep state */ 1741e22bee78STejun Heo worker->flags = WORKER_PREP; 1742c8e55f36STejun Heo } 1743c34056a3STejun Heo return worker; 1744c34056a3STejun Heo } 1745c34056a3STejun Heo 1746c34056a3STejun Heo /** 1747c34056a3STejun Heo * create_worker - create a new workqueue worker 174863d95a91STejun Heo * @pool: pool the new worker will belong to 1749c34056a3STejun Heo * 175063d95a91STejun Heo * Create a new worker which is bound to @pool. The returned worker 1751c34056a3STejun Heo * can be started by calling start_worker() or destroyed using 1752c34056a3STejun Heo * destroy_worker(). 1753c34056a3STejun Heo * 1754c34056a3STejun Heo * CONTEXT: 1755c34056a3STejun Heo * Might sleep. Does GFP_KERNEL allocations. 1756c34056a3STejun Heo * 1757c34056a3STejun Heo * RETURNS: 1758c34056a3STejun Heo * Pointer to the newly created worker. 1759c34056a3STejun Heo */ 1760bc2ae0f5STejun Heo static struct worker *create_worker(struct worker_pool *pool) 1761c34056a3STejun Heo { 176263d95a91STejun Heo struct global_cwq *gcwq = pool->gcwq; 17633270476aSTejun Heo const char *pri = worker_pool_pri(pool) ? "H" : ""; 1764c34056a3STejun Heo struct worker *worker = NULL; 1765f3421797STejun Heo int id = -1; 1766c34056a3STejun Heo 17678b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 1768bd7bdd43STejun Heo while (ida_get_new(&pool->worker_ida, &id)) { 17698b03ae3cSTejun Heo spin_unlock_irq(&gcwq->lock); 1770bd7bdd43STejun Heo if (!ida_pre_get(&pool->worker_ida, GFP_KERNEL)) 1771c34056a3STejun Heo goto fail; 17728b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 1773c34056a3STejun Heo } 17748b03ae3cSTejun Heo spin_unlock_irq(&gcwq->lock); 1775c34056a3STejun Heo 1776c34056a3STejun Heo worker = alloc_worker(); 1777c34056a3STejun Heo if (!worker) 1778c34056a3STejun Heo goto fail; 1779c34056a3STejun Heo 1780bd7bdd43STejun Heo worker->pool = pool; 1781c34056a3STejun Heo worker->id = id; 1782c34056a3STejun Heo 1783bc2ae0f5STejun Heo if (gcwq->cpu != WORK_CPU_UNBOUND) 178494dcf29aSEric Dumazet worker->task = kthread_create_on_node(worker_thread, 17853270476aSTejun Heo worker, cpu_to_node(gcwq->cpu), 17863270476aSTejun Heo "kworker/%u:%d%s", gcwq->cpu, id, pri); 1787f3421797STejun Heo else 1788f3421797STejun Heo worker->task = kthread_create(worker_thread, worker, 17893270476aSTejun Heo "kworker/u:%d%s", id, pri); 1790c34056a3STejun Heo if (IS_ERR(worker->task)) 1791c34056a3STejun Heo goto fail; 1792c34056a3STejun Heo 17933270476aSTejun Heo if (worker_pool_pri(pool)) 17943270476aSTejun Heo set_user_nice(worker->task, HIGHPRI_NICE_LEVEL); 17953270476aSTejun Heo 1796db7bccf4STejun Heo /* 1797bc2ae0f5STejun Heo * Determine CPU binding of the new worker depending on 1798bc2ae0f5STejun Heo * %GCWQ_DISASSOCIATED. The caller is responsible for ensuring the 1799bc2ae0f5STejun Heo * flag remains stable across this function. See the comments 1800bc2ae0f5STejun Heo * above the flag definition for details. 1801bc2ae0f5STejun Heo * 1802bc2ae0f5STejun Heo * As an unbound worker may later become a regular one if CPU comes 1803bc2ae0f5STejun Heo * online, make sure every worker has %PF_THREAD_BOUND set. 1804db7bccf4STejun Heo */ 1805bc2ae0f5STejun Heo if (!(gcwq->flags & GCWQ_DISASSOCIATED)) { 18068b03ae3cSTejun Heo kthread_bind(worker->task, gcwq->cpu); 1807bc2ae0f5STejun Heo } else { 1808db7bccf4STejun Heo worker->task->flags |= PF_THREAD_BOUND; 1809f3421797STejun Heo worker->flags |= WORKER_UNBOUND; 1810f3421797STejun Heo } 1811c34056a3STejun Heo 1812c34056a3STejun Heo return worker; 1813c34056a3STejun Heo fail: 1814c34056a3STejun Heo if (id >= 0) { 18158b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 1816bd7bdd43STejun Heo ida_remove(&pool->worker_ida, id); 18178b03ae3cSTejun Heo spin_unlock_irq(&gcwq->lock); 1818c34056a3STejun Heo } 1819c34056a3STejun Heo kfree(worker); 1820c34056a3STejun Heo return NULL; 1821c34056a3STejun Heo } 1822c34056a3STejun Heo 1823c34056a3STejun Heo /** 1824c34056a3STejun Heo * start_worker - start a newly created worker 1825c34056a3STejun Heo * @worker: worker to start 1826c34056a3STejun Heo * 1827c8e55f36STejun Heo * Make the gcwq aware of @worker and start it. 1828c34056a3STejun Heo * 1829c34056a3STejun Heo * CONTEXT: 18308b03ae3cSTejun Heo * spin_lock_irq(gcwq->lock). 1831c34056a3STejun Heo */ 1832c34056a3STejun Heo static void start_worker(struct worker *worker) 1833c34056a3STejun Heo { 1834cb444766STejun Heo worker->flags |= WORKER_STARTED; 1835bd7bdd43STejun Heo worker->pool->nr_workers++; 1836c8e55f36STejun Heo worker_enter_idle(worker); 1837c34056a3STejun Heo wake_up_process(worker->task); 1838c34056a3STejun Heo } 1839c34056a3STejun Heo 1840c34056a3STejun Heo /** 1841c34056a3STejun Heo * destroy_worker - destroy a workqueue worker 1842c34056a3STejun Heo * @worker: worker to be destroyed 1843c34056a3STejun Heo * 1844c8e55f36STejun Heo * Destroy @worker and adjust @gcwq stats accordingly. 1845c8e55f36STejun Heo * 1846c8e55f36STejun Heo * CONTEXT: 1847c8e55f36STejun Heo * spin_lock_irq(gcwq->lock) which is released and regrabbed. 1848c34056a3STejun Heo */ 1849c34056a3STejun Heo static void destroy_worker(struct worker *worker) 1850c34056a3STejun Heo { 1851bd7bdd43STejun Heo struct worker_pool *pool = worker->pool; 1852bd7bdd43STejun Heo struct global_cwq *gcwq = pool->gcwq; 1853c34056a3STejun Heo int id = worker->id; 1854c34056a3STejun Heo 1855c34056a3STejun Heo /* sanity check frenzy */ 1856c34056a3STejun Heo BUG_ON(worker->current_work); 1857affee4b2STejun Heo BUG_ON(!list_empty(&worker->scheduled)); 1858c34056a3STejun Heo 1859c8e55f36STejun Heo if (worker->flags & WORKER_STARTED) 1860bd7bdd43STejun Heo pool->nr_workers--; 1861c8e55f36STejun Heo if (worker->flags & WORKER_IDLE) 1862bd7bdd43STejun Heo pool->nr_idle--; 1863c8e55f36STejun Heo 1864c8e55f36STejun Heo list_del_init(&worker->entry); 1865cb444766STejun Heo worker->flags |= WORKER_DIE; 1866c8e55f36STejun Heo 1867c8e55f36STejun Heo spin_unlock_irq(&gcwq->lock); 1868c8e55f36STejun Heo 1869c34056a3STejun Heo kthread_stop(worker->task); 1870c34056a3STejun Heo kfree(worker); 1871c34056a3STejun Heo 18728b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 1873bd7bdd43STejun Heo ida_remove(&pool->worker_ida, id); 1874c34056a3STejun Heo } 1875c34056a3STejun Heo 187663d95a91STejun Heo static void idle_worker_timeout(unsigned long __pool) 1877e22bee78STejun Heo { 187863d95a91STejun Heo struct worker_pool *pool = (void *)__pool; 187963d95a91STejun Heo struct global_cwq *gcwq = pool->gcwq; 1880e22bee78STejun Heo 1881e22bee78STejun Heo spin_lock_irq(&gcwq->lock); 1882e22bee78STejun Heo 188363d95a91STejun Heo if (too_many_workers(pool)) { 1884e22bee78STejun Heo struct worker *worker; 1885e22bee78STejun Heo unsigned long expires; 1886e22bee78STejun Heo 1887e22bee78STejun Heo /* idle_list is kept in LIFO order, check the last one */ 188863d95a91STejun Heo worker = list_entry(pool->idle_list.prev, struct worker, entry); 1889e22bee78STejun Heo expires = worker->last_active + IDLE_WORKER_TIMEOUT; 1890e22bee78STejun Heo 1891e22bee78STejun Heo if (time_before(jiffies, expires)) 189263d95a91STejun Heo mod_timer(&pool->idle_timer, expires); 1893e22bee78STejun Heo else { 1894e22bee78STejun Heo /* it's been idle for too long, wake up manager */ 189511ebea50STejun Heo pool->flags |= POOL_MANAGE_WORKERS; 189663d95a91STejun Heo wake_up_worker(pool); 1897e22bee78STejun Heo } 1898e22bee78STejun Heo } 1899e22bee78STejun Heo 1900e22bee78STejun Heo spin_unlock_irq(&gcwq->lock); 1901e22bee78STejun Heo } 1902e22bee78STejun Heo 1903e22bee78STejun Heo static bool send_mayday(struct work_struct *work) 1904e22bee78STejun Heo { 1905e22bee78STejun Heo struct cpu_workqueue_struct *cwq = get_work_cwq(work); 1906e22bee78STejun Heo struct workqueue_struct *wq = cwq->wq; 1907f3421797STejun Heo unsigned int cpu; 1908e22bee78STejun Heo 1909e22bee78STejun Heo if (!(wq->flags & WQ_RESCUER)) 1910e22bee78STejun Heo return false; 1911e22bee78STejun Heo 1912e22bee78STejun Heo /* mayday mayday mayday */ 1913bd7bdd43STejun Heo cpu = cwq->pool->gcwq->cpu; 1914f3421797STejun Heo /* WORK_CPU_UNBOUND can't be set in cpumask, use cpu 0 instead */ 1915f3421797STejun Heo if (cpu == WORK_CPU_UNBOUND) 1916f3421797STejun Heo cpu = 0; 1917f2e005aaSTejun Heo if (!mayday_test_and_set_cpu(cpu, wq->mayday_mask)) 1918e22bee78STejun Heo wake_up_process(wq->rescuer->task); 1919e22bee78STejun Heo return true; 1920e22bee78STejun Heo } 1921e22bee78STejun Heo 192263d95a91STejun Heo static void gcwq_mayday_timeout(unsigned long __pool) 1923e22bee78STejun Heo { 192463d95a91STejun Heo struct worker_pool *pool = (void *)__pool; 192563d95a91STejun Heo struct global_cwq *gcwq = pool->gcwq; 1926e22bee78STejun Heo struct work_struct *work; 1927e22bee78STejun Heo 1928e22bee78STejun Heo spin_lock_irq(&gcwq->lock); 1929e22bee78STejun Heo 193063d95a91STejun Heo if (need_to_create_worker(pool)) { 1931e22bee78STejun Heo /* 1932e22bee78STejun Heo * We've been trying to create a new worker but 1933e22bee78STejun Heo * haven't been successful. We might be hitting an 1934e22bee78STejun Heo * allocation deadlock. Send distress signals to 1935e22bee78STejun Heo * rescuers. 1936e22bee78STejun Heo */ 193763d95a91STejun Heo list_for_each_entry(work, &pool->worklist, entry) 1938e22bee78STejun Heo send_mayday(work); 1939e22bee78STejun Heo } 1940e22bee78STejun Heo 1941e22bee78STejun Heo spin_unlock_irq(&gcwq->lock); 1942e22bee78STejun Heo 194363d95a91STejun Heo mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INTERVAL); 1944e22bee78STejun Heo } 1945e22bee78STejun Heo 1946e22bee78STejun Heo /** 1947e22bee78STejun Heo * maybe_create_worker - create a new worker if necessary 194863d95a91STejun Heo * @pool: pool to create a new worker for 1949e22bee78STejun Heo * 195063d95a91STejun Heo * Create a new worker for @pool if necessary. @pool is guaranteed to 1951e22bee78STejun Heo * have at least one idle worker on return from this function. If 1952e22bee78STejun Heo * creating a new worker takes longer than MAYDAY_INTERVAL, mayday is 195363d95a91STejun Heo * sent to all rescuers with works scheduled on @pool to resolve 1954e22bee78STejun Heo * possible allocation deadlock. 1955e22bee78STejun Heo * 1956e22bee78STejun Heo * On return, need_to_create_worker() is guaranteed to be false and 1957e22bee78STejun Heo * may_start_working() true. 1958e22bee78STejun Heo * 1959e22bee78STejun Heo * LOCKING: 1960e22bee78STejun Heo * spin_lock_irq(gcwq->lock) which may be released and regrabbed 1961e22bee78STejun Heo * multiple times. Does GFP_KERNEL allocations. Called only from 1962e22bee78STejun Heo * manager. 1963e22bee78STejun Heo * 1964e22bee78STejun Heo * RETURNS: 1965e22bee78STejun Heo * false if no action was taken and gcwq->lock stayed locked, true 1966e22bee78STejun Heo * otherwise. 1967e22bee78STejun Heo */ 196863d95a91STejun Heo static bool maybe_create_worker(struct worker_pool *pool) 196906bd6ebfSNamhyung Kim __releases(&gcwq->lock) 197006bd6ebfSNamhyung Kim __acquires(&gcwq->lock) 1971e22bee78STejun Heo { 197263d95a91STejun Heo struct global_cwq *gcwq = pool->gcwq; 197363d95a91STejun Heo 197463d95a91STejun Heo if (!need_to_create_worker(pool)) 1975e22bee78STejun Heo return false; 1976e22bee78STejun Heo restart: 19779f9c2364STejun Heo spin_unlock_irq(&gcwq->lock); 19789f9c2364STejun Heo 1979e22bee78STejun Heo /* if we don't make progress in MAYDAY_INITIAL_TIMEOUT, call for help */ 198063d95a91STejun Heo mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INITIAL_TIMEOUT); 1981e22bee78STejun Heo 1982e22bee78STejun Heo while (true) { 1983e22bee78STejun Heo struct worker *worker; 1984e22bee78STejun Heo 1985bc2ae0f5STejun Heo worker = create_worker(pool); 1986e22bee78STejun Heo if (worker) { 198763d95a91STejun Heo del_timer_sync(&pool->mayday_timer); 1988e22bee78STejun Heo spin_lock_irq(&gcwq->lock); 1989e22bee78STejun Heo start_worker(worker); 199063d95a91STejun Heo BUG_ON(need_to_create_worker(pool)); 1991e22bee78STejun Heo return true; 1992e22bee78STejun Heo } 1993e22bee78STejun Heo 199463d95a91STejun Heo if (!need_to_create_worker(pool)) 1995e22bee78STejun Heo break; 1996e22bee78STejun Heo 1997e22bee78STejun Heo __set_current_state(TASK_INTERRUPTIBLE); 1998e22bee78STejun Heo schedule_timeout(CREATE_COOLDOWN); 19999f9c2364STejun Heo 200063d95a91STejun Heo if (!need_to_create_worker(pool)) 2001e22bee78STejun Heo break; 2002e22bee78STejun Heo } 2003e22bee78STejun Heo 200463d95a91STejun Heo del_timer_sync(&pool->mayday_timer); 2005e22bee78STejun Heo spin_lock_irq(&gcwq->lock); 200663d95a91STejun Heo if (need_to_create_worker(pool)) 2007e22bee78STejun Heo goto restart; 2008e22bee78STejun Heo return true; 2009e22bee78STejun Heo } 2010e22bee78STejun Heo 2011e22bee78STejun Heo /** 2012e22bee78STejun Heo * maybe_destroy_worker - destroy workers which have been idle for a while 201363d95a91STejun Heo * @pool: pool to destroy workers for 2014e22bee78STejun Heo * 201563d95a91STejun Heo * Destroy @pool workers which have been idle for longer than 2016e22bee78STejun Heo * IDLE_WORKER_TIMEOUT. 2017e22bee78STejun Heo * 2018e22bee78STejun Heo * LOCKING: 2019e22bee78STejun Heo * spin_lock_irq(gcwq->lock) which may be released and regrabbed 2020e22bee78STejun Heo * multiple times. Called only from manager. 2021e22bee78STejun Heo * 2022e22bee78STejun Heo * RETURNS: 2023e22bee78STejun Heo * false if no action was taken and gcwq->lock stayed locked, true 2024e22bee78STejun Heo * otherwise. 2025e22bee78STejun Heo */ 202663d95a91STejun Heo static bool maybe_destroy_workers(struct worker_pool *pool) 2027e22bee78STejun Heo { 2028e22bee78STejun Heo bool ret = false; 2029e22bee78STejun Heo 203063d95a91STejun Heo while (too_many_workers(pool)) { 2031e22bee78STejun Heo struct worker *worker; 2032e22bee78STejun Heo unsigned long expires; 2033e22bee78STejun Heo 203463d95a91STejun Heo worker = list_entry(pool->idle_list.prev, struct worker, entry); 2035e22bee78STejun Heo expires = worker->last_active + IDLE_WORKER_TIMEOUT; 2036e22bee78STejun Heo 2037e22bee78STejun Heo if (time_before(jiffies, expires)) { 203863d95a91STejun Heo mod_timer(&pool->idle_timer, expires); 2039e22bee78STejun Heo break; 2040e22bee78STejun Heo } 2041e22bee78STejun Heo 2042e22bee78STejun Heo destroy_worker(worker); 2043e22bee78STejun Heo ret = true; 2044e22bee78STejun Heo } 2045e22bee78STejun Heo 2046e22bee78STejun Heo return ret; 2047e22bee78STejun Heo } 2048e22bee78STejun Heo 2049e22bee78STejun Heo /** 2050e22bee78STejun Heo * manage_workers - manage worker pool 2051e22bee78STejun Heo * @worker: self 2052e22bee78STejun Heo * 2053e22bee78STejun Heo * Assume the manager role and manage gcwq worker pool @worker belongs 2054e22bee78STejun Heo * to. At any given time, there can be only zero or one manager per 2055e22bee78STejun Heo * gcwq. The exclusion is handled automatically by this function. 2056e22bee78STejun Heo * 2057e22bee78STejun Heo * The caller can safely start processing works on false return. On 2058e22bee78STejun Heo * true return, it's guaranteed that need_to_create_worker() is false 2059e22bee78STejun Heo * and may_start_working() is true. 2060e22bee78STejun Heo * 2061e22bee78STejun Heo * CONTEXT: 2062e22bee78STejun Heo * spin_lock_irq(gcwq->lock) which may be released and regrabbed 2063e22bee78STejun Heo * multiple times. Does GFP_KERNEL allocations. 2064e22bee78STejun Heo * 2065e22bee78STejun Heo * RETURNS: 2066e22bee78STejun Heo * false if no action was taken and gcwq->lock stayed locked, true if 2067e22bee78STejun Heo * some action was taken. 2068e22bee78STejun Heo */ 2069e22bee78STejun Heo static bool manage_workers(struct worker *worker) 2070e22bee78STejun Heo { 207163d95a91STejun Heo struct worker_pool *pool = worker->pool; 2072e22bee78STejun Heo bool ret = false; 2073e22bee78STejun Heo 2074ee378aa4SLai Jiangshan if (pool->flags & POOL_MANAGING_WORKERS) 2075e22bee78STejun Heo return ret; 2076e22bee78STejun Heo 2077552a37e9SLai Jiangshan pool->flags |= POOL_MANAGING_WORKERS; 2078ee378aa4SLai Jiangshan 2079ee378aa4SLai Jiangshan /* 2080ee378aa4SLai Jiangshan * To simplify both worker management and CPU hotplug, hold off 2081ee378aa4SLai Jiangshan * management while hotplug is in progress. CPU hotplug path can't 2082ee378aa4SLai Jiangshan * grab %POOL_MANAGING_WORKERS to achieve this because that can 2083ee378aa4SLai Jiangshan * lead to idle worker depletion (all become busy thinking someone 2084ee378aa4SLai Jiangshan * else is managing) which in turn can result in deadlock under 2085b2eb83d1SLai Jiangshan * extreme circumstances. Use @pool->assoc_mutex to synchronize 2086ee378aa4SLai Jiangshan * manager against CPU hotplug. 2087ee378aa4SLai Jiangshan * 2088b2eb83d1SLai Jiangshan * assoc_mutex would always be free unless CPU hotplug is in 2089ee378aa4SLai Jiangshan * progress. trylock first without dropping @gcwq->lock. 2090ee378aa4SLai Jiangshan */ 2091b2eb83d1SLai Jiangshan if (unlikely(!mutex_trylock(&pool->assoc_mutex))) { 2092ee378aa4SLai Jiangshan spin_unlock_irq(&pool->gcwq->lock); 2093b2eb83d1SLai Jiangshan mutex_lock(&pool->assoc_mutex); 2094ee378aa4SLai Jiangshan /* 2095ee378aa4SLai Jiangshan * CPU hotplug could have happened while we were waiting 2096b2eb83d1SLai Jiangshan * for assoc_mutex. Hotplug itself can't handle us 2097ee378aa4SLai Jiangshan * because manager isn't either on idle or busy list, and 2098ee378aa4SLai Jiangshan * @gcwq's state and ours could have deviated. 2099ee378aa4SLai Jiangshan * 2100b2eb83d1SLai Jiangshan * As hotplug is now excluded via assoc_mutex, we can 2101ee378aa4SLai Jiangshan * simply try to bind. It will succeed or fail depending 2102ee378aa4SLai Jiangshan * on @gcwq's current state. Try it and adjust 2103ee378aa4SLai Jiangshan * %WORKER_UNBOUND accordingly. 2104ee378aa4SLai Jiangshan */ 2105ee378aa4SLai Jiangshan if (worker_maybe_bind_and_lock(worker)) 2106ee378aa4SLai Jiangshan worker->flags &= ~WORKER_UNBOUND; 2107ee378aa4SLai Jiangshan else 2108ee378aa4SLai Jiangshan worker->flags |= WORKER_UNBOUND; 2109ee378aa4SLai Jiangshan 2110ee378aa4SLai Jiangshan ret = true; 2111ee378aa4SLai Jiangshan } 2112ee378aa4SLai Jiangshan 211311ebea50STejun Heo pool->flags &= ~POOL_MANAGE_WORKERS; 2114e22bee78STejun Heo 2115e22bee78STejun Heo /* 2116e22bee78STejun Heo * Destroy and then create so that may_start_working() is true 2117e22bee78STejun Heo * on return. 2118e22bee78STejun Heo */ 211963d95a91STejun Heo ret |= maybe_destroy_workers(pool); 212063d95a91STejun Heo ret |= maybe_create_worker(pool); 2121e22bee78STejun Heo 2122552a37e9SLai Jiangshan pool->flags &= ~POOL_MANAGING_WORKERS; 2123b2eb83d1SLai Jiangshan mutex_unlock(&pool->assoc_mutex); 2124e22bee78STejun Heo return ret; 2125e22bee78STejun Heo } 2126e22bee78STejun Heo 2127a62428c0STejun Heo /** 2128a62428c0STejun Heo * process_one_work - process single work 2129c34056a3STejun Heo * @worker: self 2130a62428c0STejun Heo * @work: work to process 2131a62428c0STejun Heo * 2132a62428c0STejun Heo * Process @work. This function contains all the logics necessary to 2133a62428c0STejun Heo * process a single work including synchronization against and 2134a62428c0STejun Heo * interaction with other workers on the same cpu, queueing and 2135a62428c0STejun Heo * flushing. As long as context requirement is met, any worker can 2136a62428c0STejun Heo * call this function to process a work. 2137a62428c0STejun Heo * 2138a62428c0STejun Heo * CONTEXT: 21398b03ae3cSTejun Heo * spin_lock_irq(gcwq->lock) which is released and regrabbed. 2140a62428c0STejun Heo */ 2141c34056a3STejun Heo static void process_one_work(struct worker *worker, struct work_struct *work) 214206bd6ebfSNamhyung Kim __releases(&gcwq->lock) 214306bd6ebfSNamhyung Kim __acquires(&gcwq->lock) 21441da177e4SLinus Torvalds { 21457e11629dSTejun Heo struct cpu_workqueue_struct *cwq = get_work_cwq(work); 2146bd7bdd43STejun Heo struct worker_pool *pool = worker->pool; 2147bd7bdd43STejun Heo struct global_cwq *gcwq = pool->gcwq; 2148fb0e7bebSTejun Heo bool cpu_intensive = cwq->wq->flags & WQ_CPU_INTENSIVE; 214973f53c4aSTejun Heo int work_color; 21507e11629dSTejun Heo struct worker *collision; 21514e6045f1SJohannes Berg #ifdef CONFIG_LOCKDEP 21524e6045f1SJohannes Berg /* 2153a62428c0STejun Heo * It is permissible to free the struct work_struct from 2154a62428c0STejun Heo * inside the function that is called from it, this we need to 2155a62428c0STejun Heo * take into account for lockdep too. To avoid bogus "held 2156a62428c0STejun Heo * lock freed" warnings as well as problems when looking into 2157a62428c0STejun Heo * work->lockdep_map, make a copy and use that here. 21584e6045f1SJohannes Berg */ 21594d82a1deSPeter Zijlstra struct lockdep_map lockdep_map; 21604d82a1deSPeter Zijlstra 21614d82a1deSPeter Zijlstra lockdep_copy_map(&lockdep_map, &work->lockdep_map); 21624e6045f1SJohannes Berg #endif 21636fec10a1STejun Heo /* 21646fec10a1STejun Heo * Ensure we're on the correct CPU. DISASSOCIATED test is 21656fec10a1STejun Heo * necessary to avoid spurious warnings from rescuers servicing the 21666fec10a1STejun Heo * unbound or a disassociated gcwq. 21676fec10a1STejun Heo */ 21685f7dabfdSLai Jiangshan WARN_ON_ONCE(!(worker->flags & WORKER_UNBOUND) && 21696fec10a1STejun Heo !(gcwq->flags & GCWQ_DISASSOCIATED) && 217025511a47STejun Heo raw_smp_processor_id() != gcwq->cpu); 217125511a47STejun Heo 21727e11629dSTejun Heo /* 21737e11629dSTejun Heo * A single work shouldn't be executed concurrently by 21747e11629dSTejun Heo * multiple workers on a single cpu. Check whether anyone is 21757e11629dSTejun Heo * already processing the work. If so, defer the work to the 21767e11629dSTejun Heo * currently executing one. 21777e11629dSTejun Heo */ 217842f8570fSSasha Levin collision = find_worker_executing_work(gcwq, work); 21797e11629dSTejun Heo if (unlikely(collision)) { 21807e11629dSTejun Heo move_linked_works(work, &collision->scheduled, NULL); 21817e11629dSTejun Heo return; 21827e11629dSTejun Heo } 21831da177e4SLinus Torvalds 21848930cabaSTejun Heo /* claim and dequeue */ 21851da177e4SLinus Torvalds debug_work_deactivate(work); 2186023f27d3STejun Heo hash_add(gcwq->busy_hash, &worker->hentry, (unsigned long)work); 2187c34056a3STejun Heo worker->current_work = work; 2188a2c1c57bSTejun Heo worker->current_func = work->func; 21898cca0eeaSTejun Heo worker->current_cwq = cwq; 219073f53c4aSTejun Heo work_color = get_work_color(work); 21917a22ad75STejun Heo 2192a62428c0STejun Heo list_del_init(&work->entry); 2193a62428c0STejun Heo 2194649027d7STejun Heo /* 2195fb0e7bebSTejun Heo * CPU intensive works don't participate in concurrency 2196fb0e7bebSTejun Heo * management. They're the scheduler's responsibility. 2197fb0e7bebSTejun Heo */ 2198fb0e7bebSTejun Heo if (unlikely(cpu_intensive)) 2199fb0e7bebSTejun Heo worker_set_flags(worker, WORKER_CPU_INTENSIVE, true); 2200fb0e7bebSTejun Heo 2201974271c4STejun Heo /* 2202974271c4STejun Heo * Unbound gcwq isn't concurrency managed and work items should be 2203974271c4STejun Heo * executed ASAP. Wake up another worker if necessary. 2204974271c4STejun Heo */ 220563d95a91STejun Heo if ((worker->flags & WORKER_UNBOUND) && need_more_worker(pool)) 220663d95a91STejun Heo wake_up_worker(pool); 2207974271c4STejun Heo 22088930cabaSTejun Heo /* 220923657bb1STejun Heo * Record the last CPU and clear PENDING which should be the last 221023657bb1STejun Heo * update to @work. Also, do this inside @gcwq->lock so that 221123657bb1STejun Heo * PENDING and queued state changes happen together while IRQ is 221223657bb1STejun Heo * disabled. 22138930cabaSTejun Heo */ 22148930cabaSTejun Heo set_work_cpu_and_clear_pending(work, gcwq->cpu); 22151da177e4SLinus Torvalds 22161da177e4SLinus Torvalds spin_unlock_irq(&gcwq->lock); 2217365970a1SDavid Howells 2218e159489bSTejun Heo lock_map_acquire_read(&cwq->wq->lockdep_map); 22193295f0efSIngo Molnar lock_map_acquire(&lockdep_map); 2220e36c886aSArjan van de Ven trace_workqueue_execute_start(work); 2221a2c1c57bSTejun Heo worker->current_func(work); 2222e36c886aSArjan van de Ven /* 2223e36c886aSArjan van de Ven * While we must be careful to not use "work" after this, the trace 2224e36c886aSArjan van de Ven * point will only record its address. 2225e36c886aSArjan van de Ven */ 2226e36c886aSArjan van de Ven trace_workqueue_execute_end(work); 22273295f0efSIngo Molnar lock_map_release(&lockdep_map); 22283295f0efSIngo Molnar lock_map_release(&cwq->wq->lockdep_map); 22291da177e4SLinus Torvalds 2230d5abe669SPeter Zijlstra if (unlikely(in_atomic() || lockdep_depth(current) > 0)) { 2231044c782cSValentin Ilie pr_err("BUG: workqueue leaked lock or atomic: %s/0x%08x/%d\n" 2232044c782cSValentin Ilie " last function: %pf\n", 2233a2c1c57bSTejun Heo current->comm, preempt_count(), task_pid_nr(current), 2234a2c1c57bSTejun Heo worker->current_func); 2235d5abe669SPeter Zijlstra debug_show_held_locks(current); 2236d5abe669SPeter Zijlstra dump_stack(); 2237d5abe669SPeter Zijlstra } 2238d5abe669SPeter Zijlstra 22398b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 2240a62428c0STejun Heo 2241fb0e7bebSTejun Heo /* clear cpu intensive status */ 2242fb0e7bebSTejun Heo if (unlikely(cpu_intensive)) 2243fb0e7bebSTejun Heo worker_clr_flags(worker, WORKER_CPU_INTENSIVE); 2244fb0e7bebSTejun Heo 2245a62428c0STejun Heo /* we're done with it, release */ 224642f8570fSSasha Levin hash_del(&worker->hentry); 2247c34056a3STejun Heo worker->current_work = NULL; 2248a2c1c57bSTejun Heo worker->current_func = NULL; 22498cca0eeaSTejun Heo worker->current_cwq = NULL; 2250b3f9f405SLai Jiangshan cwq_dec_nr_in_flight(cwq, work_color); 22511da177e4SLinus Torvalds } 22521da177e4SLinus Torvalds 2253affee4b2STejun Heo /** 2254affee4b2STejun Heo * process_scheduled_works - process scheduled works 2255affee4b2STejun Heo * @worker: self 2256affee4b2STejun Heo * 2257affee4b2STejun Heo * Process all scheduled works. Please note that the scheduled list 2258affee4b2STejun Heo * may change while processing a work, so this function repeatedly 2259affee4b2STejun Heo * fetches a work from the top and executes it. 2260affee4b2STejun Heo * 2261affee4b2STejun Heo * CONTEXT: 22628b03ae3cSTejun Heo * spin_lock_irq(gcwq->lock) which may be released and regrabbed 2263affee4b2STejun Heo * multiple times. 2264affee4b2STejun Heo */ 2265affee4b2STejun Heo static void process_scheduled_works(struct worker *worker) 22661da177e4SLinus Torvalds { 2267affee4b2STejun Heo while (!list_empty(&worker->scheduled)) { 2268affee4b2STejun Heo struct work_struct *work = list_first_entry(&worker->scheduled, 2269a62428c0STejun Heo struct work_struct, entry); 2270c34056a3STejun Heo process_one_work(worker, work); 2271a62428c0STejun Heo } 22721da177e4SLinus Torvalds } 22731da177e4SLinus Torvalds 22744690c4abSTejun Heo /** 22754690c4abSTejun Heo * worker_thread - the worker thread function 2276c34056a3STejun Heo * @__worker: self 22774690c4abSTejun Heo * 2278e22bee78STejun Heo * The gcwq worker thread function. There's a single dynamic pool of 2279e22bee78STejun Heo * these per each cpu. These workers process all works regardless of 2280e22bee78STejun Heo * their specific target workqueue. The only exception is works which 2281e22bee78STejun Heo * belong to workqueues with a rescuer which will be explained in 2282e22bee78STejun Heo * rescuer_thread(). 22834690c4abSTejun Heo */ 2284c34056a3STejun Heo static int worker_thread(void *__worker) 22851da177e4SLinus Torvalds { 2286c34056a3STejun Heo struct worker *worker = __worker; 2287bd7bdd43STejun Heo struct worker_pool *pool = worker->pool; 2288bd7bdd43STejun Heo struct global_cwq *gcwq = pool->gcwq; 22891da177e4SLinus Torvalds 2290e22bee78STejun Heo /* tell the scheduler that this is a workqueue worker */ 2291e22bee78STejun Heo worker->task->flags |= PF_WQ_WORKER; 2292c8e55f36STejun Heo woke_up: 22938b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 2294affee4b2STejun Heo 22955f7dabfdSLai Jiangshan /* we are off idle list if destruction or rebind is requested */ 22965f7dabfdSLai Jiangshan if (unlikely(list_empty(&worker->entry))) { 2297c8e55f36STejun Heo spin_unlock_irq(&gcwq->lock); 229825511a47STejun Heo 22995f7dabfdSLai Jiangshan /* if DIE is set, destruction is requested */ 230025511a47STejun Heo if (worker->flags & WORKER_DIE) { 2301e22bee78STejun Heo worker->task->flags &= ~PF_WQ_WORKER; 2302c8e55f36STejun Heo return 0; 2303c8e55f36STejun Heo } 2304c8e55f36STejun Heo 23055f7dabfdSLai Jiangshan /* otherwise, rebind */ 230625511a47STejun Heo idle_worker_rebind(worker); 230725511a47STejun Heo goto woke_up; 230825511a47STejun Heo } 230925511a47STejun Heo 2310c8e55f36STejun Heo worker_leave_idle(worker); 2311db7bccf4STejun Heo recheck: 2312e22bee78STejun Heo /* no more worker necessary? */ 231363d95a91STejun Heo if (!need_more_worker(pool)) 2314e22bee78STejun Heo goto sleep; 2315e22bee78STejun Heo 2316e22bee78STejun Heo /* do we need to manage? */ 231763d95a91STejun Heo if (unlikely(!may_start_working(pool)) && manage_workers(worker)) 2318e22bee78STejun Heo goto recheck; 2319e22bee78STejun Heo 2320c8e55f36STejun Heo /* 2321c8e55f36STejun Heo * ->scheduled list can only be filled while a worker is 2322c8e55f36STejun Heo * preparing to process a work or actually processing it. 2323c8e55f36STejun Heo * Make sure nobody diddled with it while I was sleeping. 2324c8e55f36STejun Heo */ 2325c8e55f36STejun Heo BUG_ON(!list_empty(&worker->scheduled)); 2326c8e55f36STejun Heo 2327e22bee78STejun Heo /* 2328e22bee78STejun Heo * When control reaches this point, we're guaranteed to have 2329e22bee78STejun Heo * at least one idle worker or that someone else has already 2330e22bee78STejun Heo * assumed the manager role. 2331e22bee78STejun Heo */ 2332e22bee78STejun Heo worker_clr_flags(worker, WORKER_PREP); 2333e22bee78STejun Heo 2334e22bee78STejun Heo do { 2335affee4b2STejun Heo struct work_struct *work = 2336bd7bdd43STejun Heo list_first_entry(&pool->worklist, 2337affee4b2STejun Heo struct work_struct, entry); 2338affee4b2STejun Heo 2339c8e55f36STejun Heo if (likely(!(*work_data_bits(work) & WORK_STRUCT_LINKED))) { 2340affee4b2STejun Heo /* optimization path, not strictly necessary */ 2341affee4b2STejun Heo process_one_work(worker, work); 2342affee4b2STejun Heo if (unlikely(!list_empty(&worker->scheduled))) 2343affee4b2STejun Heo process_scheduled_works(worker); 2344affee4b2STejun Heo } else { 2345c8e55f36STejun Heo move_linked_works(work, &worker->scheduled, NULL); 2346affee4b2STejun Heo process_scheduled_works(worker); 2347affee4b2STejun Heo } 234863d95a91STejun Heo } while (keep_working(pool)); 2349affee4b2STejun Heo 2350e22bee78STejun Heo worker_set_flags(worker, WORKER_PREP, false); 2351d313dd85STejun Heo sleep: 235263d95a91STejun Heo if (unlikely(need_to_manage_workers(pool)) && manage_workers(worker)) 2353e22bee78STejun Heo goto recheck; 2354d313dd85STejun Heo 2355c8e55f36STejun Heo /* 2356e22bee78STejun Heo * gcwq->lock is held and there's no work to process and no 2357e22bee78STejun Heo * need to manage, sleep. Workers are woken up only while 2358e22bee78STejun Heo * holding gcwq->lock or from local cpu, so setting the 2359e22bee78STejun Heo * current state before releasing gcwq->lock is enough to 2360e22bee78STejun Heo * prevent losing any event. 2361c8e55f36STejun Heo */ 2362c8e55f36STejun Heo worker_enter_idle(worker); 2363c8e55f36STejun Heo __set_current_state(TASK_INTERRUPTIBLE); 23648b03ae3cSTejun Heo spin_unlock_irq(&gcwq->lock); 23651da177e4SLinus Torvalds schedule(); 2366c8e55f36STejun Heo goto woke_up; 23671da177e4SLinus Torvalds } 23681da177e4SLinus Torvalds 2369e22bee78STejun Heo /** 2370e22bee78STejun Heo * rescuer_thread - the rescuer thread function 2371111c225aSTejun Heo * @__rescuer: self 2372e22bee78STejun Heo * 2373e22bee78STejun Heo * Workqueue rescuer thread function. There's one rescuer for each 2374e22bee78STejun Heo * workqueue which has WQ_RESCUER set. 2375e22bee78STejun Heo * 2376e22bee78STejun Heo * Regular work processing on a gcwq may block trying to create a new 2377e22bee78STejun Heo * worker which uses GFP_KERNEL allocation which has slight chance of 2378e22bee78STejun Heo * developing into deadlock if some works currently on the same queue 2379e22bee78STejun Heo * need to be processed to satisfy the GFP_KERNEL allocation. This is 2380e22bee78STejun Heo * the problem rescuer solves. 2381e22bee78STejun Heo * 2382e22bee78STejun Heo * When such condition is possible, the gcwq summons rescuers of all 2383e22bee78STejun Heo * workqueues which have works queued on the gcwq and let them process 2384e22bee78STejun Heo * those works so that forward progress can be guaranteed. 2385e22bee78STejun Heo * 2386e22bee78STejun Heo * This should happen rarely. 2387e22bee78STejun Heo */ 2388111c225aSTejun Heo static int rescuer_thread(void *__rescuer) 2389e22bee78STejun Heo { 2390111c225aSTejun Heo struct worker *rescuer = __rescuer; 2391111c225aSTejun Heo struct workqueue_struct *wq = rescuer->rescue_wq; 2392e22bee78STejun Heo struct list_head *scheduled = &rescuer->scheduled; 2393f3421797STejun Heo bool is_unbound = wq->flags & WQ_UNBOUND; 2394e22bee78STejun Heo unsigned int cpu; 2395e22bee78STejun Heo 2396e22bee78STejun Heo set_user_nice(current, RESCUER_NICE_LEVEL); 2397111c225aSTejun Heo 2398111c225aSTejun Heo /* 2399111c225aSTejun Heo * Mark rescuer as worker too. As WORKER_PREP is never cleared, it 2400111c225aSTejun Heo * doesn't participate in concurrency management. 2401111c225aSTejun Heo */ 2402111c225aSTejun Heo rescuer->task->flags |= PF_WQ_WORKER; 2403e22bee78STejun Heo repeat: 2404e22bee78STejun Heo set_current_state(TASK_INTERRUPTIBLE); 24051da177e4SLinus Torvalds 2406412d32e6SMike Galbraith if (kthread_should_stop()) { 2407412d32e6SMike Galbraith __set_current_state(TASK_RUNNING); 2408111c225aSTejun Heo rescuer->task->flags &= ~PF_WQ_WORKER; 2409e22bee78STejun Heo return 0; 2410412d32e6SMike Galbraith } 24111da177e4SLinus Torvalds 2412f3421797STejun Heo /* 2413f3421797STejun Heo * See whether any cpu is asking for help. Unbounded 2414f3421797STejun Heo * workqueues use cpu 0 in mayday_mask for CPU_UNBOUND. 2415f3421797STejun Heo */ 2416f2e005aaSTejun Heo for_each_mayday_cpu(cpu, wq->mayday_mask) { 2417f3421797STejun Heo unsigned int tcpu = is_unbound ? WORK_CPU_UNBOUND : cpu; 2418f3421797STejun Heo struct cpu_workqueue_struct *cwq = get_cwq(tcpu, wq); 2419bd7bdd43STejun Heo struct worker_pool *pool = cwq->pool; 2420bd7bdd43STejun Heo struct global_cwq *gcwq = pool->gcwq; 2421e22bee78STejun Heo struct work_struct *work, *n; 2422e22bee78STejun Heo 2423e22bee78STejun Heo __set_current_state(TASK_RUNNING); 2424f2e005aaSTejun Heo mayday_clear_cpu(cpu, wq->mayday_mask); 2425e22bee78STejun Heo 2426e22bee78STejun Heo /* migrate to the target cpu if possible */ 2427bd7bdd43STejun Heo rescuer->pool = pool; 2428e22bee78STejun Heo worker_maybe_bind_and_lock(rescuer); 2429e22bee78STejun Heo 2430e22bee78STejun Heo /* 2431e22bee78STejun Heo * Slurp in all works issued via this workqueue and 2432e22bee78STejun Heo * process'em. 2433e22bee78STejun Heo */ 2434e22bee78STejun Heo BUG_ON(!list_empty(&rescuer->scheduled)); 2435bd7bdd43STejun Heo list_for_each_entry_safe(work, n, &pool->worklist, entry) 2436e22bee78STejun Heo if (get_work_cwq(work) == cwq) 2437e22bee78STejun Heo move_linked_works(work, scheduled, &n); 2438e22bee78STejun Heo 2439e22bee78STejun Heo process_scheduled_works(rescuer); 24407576958aSTejun Heo 24417576958aSTejun Heo /* 24427576958aSTejun Heo * Leave this gcwq. If keep_working() is %true, notify a 24437576958aSTejun Heo * regular worker; otherwise, we end up with 0 concurrency 24447576958aSTejun Heo * and stalling the execution. 24457576958aSTejun Heo */ 244663d95a91STejun Heo if (keep_working(pool)) 244763d95a91STejun Heo wake_up_worker(pool); 24487576958aSTejun Heo 2449e22bee78STejun Heo spin_unlock_irq(&gcwq->lock); 24501da177e4SLinus Torvalds } 24511da177e4SLinus Torvalds 2452111c225aSTejun Heo /* rescuers should never participate in concurrency management */ 2453111c225aSTejun Heo WARN_ON_ONCE(!(rescuer->flags & WORKER_NOT_RUNNING)); 2454e22bee78STejun Heo schedule(); 2455e22bee78STejun Heo goto repeat; 24561da177e4SLinus Torvalds } 24571da177e4SLinus Torvalds 2458fc2e4d70SOleg Nesterov struct wq_barrier { 2459fc2e4d70SOleg Nesterov struct work_struct work; 2460fc2e4d70SOleg Nesterov struct completion done; 2461fc2e4d70SOleg Nesterov }; 2462fc2e4d70SOleg Nesterov 2463fc2e4d70SOleg Nesterov static void wq_barrier_func(struct work_struct *work) 2464fc2e4d70SOleg Nesterov { 2465fc2e4d70SOleg Nesterov struct wq_barrier *barr = container_of(work, struct wq_barrier, work); 2466fc2e4d70SOleg Nesterov complete(&barr->done); 2467fc2e4d70SOleg Nesterov } 2468fc2e4d70SOleg Nesterov 24694690c4abSTejun Heo /** 24704690c4abSTejun Heo * insert_wq_barrier - insert a barrier work 24714690c4abSTejun Heo * @cwq: cwq to insert barrier into 24724690c4abSTejun Heo * @barr: wq_barrier to insert 2473affee4b2STejun Heo * @target: target work to attach @barr to 2474affee4b2STejun Heo * @worker: worker currently executing @target, NULL if @target is not executing 24754690c4abSTejun Heo * 2476affee4b2STejun Heo * @barr is linked to @target such that @barr is completed only after 2477affee4b2STejun Heo * @target finishes execution. Please note that the ordering 2478affee4b2STejun Heo * guarantee is observed only with respect to @target and on the local 2479affee4b2STejun Heo * cpu. 2480affee4b2STejun Heo * 2481affee4b2STejun Heo * Currently, a queued barrier can't be canceled. This is because 2482affee4b2STejun Heo * try_to_grab_pending() can't determine whether the work to be 2483affee4b2STejun Heo * grabbed is at the head of the queue and thus can't clear LINKED 2484affee4b2STejun Heo * flag of the previous work while there must be a valid next work 2485affee4b2STejun Heo * after a work with LINKED flag set. 2486affee4b2STejun Heo * 2487affee4b2STejun Heo * Note that when @worker is non-NULL, @target may be modified 2488affee4b2STejun Heo * underneath us, so we can't reliably determine cwq from @target. 24894690c4abSTejun Heo * 24904690c4abSTejun Heo * CONTEXT: 24918b03ae3cSTejun Heo * spin_lock_irq(gcwq->lock). 24924690c4abSTejun Heo */ 249383c22520SOleg Nesterov static void insert_wq_barrier(struct cpu_workqueue_struct *cwq, 2494affee4b2STejun Heo struct wq_barrier *barr, 2495affee4b2STejun Heo struct work_struct *target, struct worker *worker) 2496fc2e4d70SOleg Nesterov { 2497affee4b2STejun Heo struct list_head *head; 2498affee4b2STejun Heo unsigned int linked = 0; 2499affee4b2STejun Heo 2500dc186ad7SThomas Gleixner /* 25018b03ae3cSTejun Heo * debugobject calls are safe here even with gcwq->lock locked 2502dc186ad7SThomas Gleixner * as we know for sure that this will not trigger any of the 2503dc186ad7SThomas Gleixner * checks and call back into the fixup functions where we 2504dc186ad7SThomas Gleixner * might deadlock. 2505dc186ad7SThomas Gleixner */ 2506ca1cab37SAndrew Morton INIT_WORK_ONSTACK(&barr->work, wq_barrier_func); 250722df02bbSTejun Heo __set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&barr->work)); 2508fc2e4d70SOleg Nesterov init_completion(&barr->done); 250983c22520SOleg Nesterov 2510affee4b2STejun Heo /* 2511affee4b2STejun Heo * If @target is currently being executed, schedule the 2512affee4b2STejun Heo * barrier to the worker; otherwise, put it after @target. 2513affee4b2STejun Heo */ 2514affee4b2STejun Heo if (worker) 2515affee4b2STejun Heo head = worker->scheduled.next; 2516affee4b2STejun Heo else { 2517affee4b2STejun Heo unsigned long *bits = work_data_bits(target); 2518affee4b2STejun Heo 2519affee4b2STejun Heo head = target->entry.next; 2520affee4b2STejun Heo /* there can already be other linked works, inherit and set */ 2521affee4b2STejun Heo linked = *bits & WORK_STRUCT_LINKED; 2522affee4b2STejun Heo __set_bit(WORK_STRUCT_LINKED_BIT, bits); 2523affee4b2STejun Heo } 2524affee4b2STejun Heo 2525dc186ad7SThomas Gleixner debug_work_activate(&barr->work); 2526affee4b2STejun Heo insert_work(cwq, &barr->work, head, 2527affee4b2STejun Heo work_color_to_flags(WORK_NO_COLOR) | linked); 2528fc2e4d70SOleg Nesterov } 2529fc2e4d70SOleg Nesterov 253073f53c4aSTejun Heo /** 253173f53c4aSTejun Heo * flush_workqueue_prep_cwqs - prepare cwqs for workqueue flushing 253273f53c4aSTejun Heo * @wq: workqueue being flushed 253373f53c4aSTejun Heo * @flush_color: new flush color, < 0 for no-op 253473f53c4aSTejun Heo * @work_color: new work color, < 0 for no-op 253573f53c4aSTejun Heo * 253673f53c4aSTejun Heo * Prepare cwqs for workqueue flushing. 253773f53c4aSTejun Heo * 253873f53c4aSTejun Heo * If @flush_color is non-negative, flush_color on all cwqs should be 253973f53c4aSTejun Heo * -1. If no cwq has in-flight commands at the specified color, all 254073f53c4aSTejun Heo * cwq->flush_color's stay at -1 and %false is returned. If any cwq 254173f53c4aSTejun Heo * has in flight commands, its cwq->flush_color is set to 254273f53c4aSTejun Heo * @flush_color, @wq->nr_cwqs_to_flush is updated accordingly, cwq 254373f53c4aSTejun Heo * wakeup logic is armed and %true is returned. 254473f53c4aSTejun Heo * 254573f53c4aSTejun Heo * The caller should have initialized @wq->first_flusher prior to 254673f53c4aSTejun Heo * calling this function with non-negative @flush_color. If 254773f53c4aSTejun Heo * @flush_color is negative, no flush color update is done and %false 254873f53c4aSTejun Heo * is returned. 254973f53c4aSTejun Heo * 255073f53c4aSTejun Heo * If @work_color is non-negative, all cwqs should have the same 255173f53c4aSTejun Heo * work_color which is previous to @work_color and all will be 255273f53c4aSTejun Heo * advanced to @work_color. 255373f53c4aSTejun Heo * 255473f53c4aSTejun Heo * CONTEXT: 255573f53c4aSTejun Heo * mutex_lock(wq->flush_mutex). 255673f53c4aSTejun Heo * 255773f53c4aSTejun Heo * RETURNS: 255873f53c4aSTejun Heo * %true if @flush_color >= 0 and there's something to flush. %false 255973f53c4aSTejun Heo * otherwise. 256073f53c4aSTejun Heo */ 256173f53c4aSTejun Heo static bool flush_workqueue_prep_cwqs(struct workqueue_struct *wq, 256273f53c4aSTejun Heo int flush_color, int work_color) 25631da177e4SLinus Torvalds { 256473f53c4aSTejun Heo bool wait = false; 256573f53c4aSTejun Heo unsigned int cpu; 25661da177e4SLinus Torvalds 256773f53c4aSTejun Heo if (flush_color >= 0) { 256873f53c4aSTejun Heo BUG_ON(atomic_read(&wq->nr_cwqs_to_flush)); 256973f53c4aSTejun Heo atomic_set(&wq->nr_cwqs_to_flush, 1); 2570dc186ad7SThomas Gleixner } 257114441960SOleg Nesterov 2572f3421797STejun Heo for_each_cwq_cpu(cpu, wq) { 257373f53c4aSTejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 2574bd7bdd43STejun Heo struct global_cwq *gcwq = cwq->pool->gcwq; 25751da177e4SLinus Torvalds 25768b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 257773f53c4aSTejun Heo 257873f53c4aSTejun Heo if (flush_color >= 0) { 257973f53c4aSTejun Heo BUG_ON(cwq->flush_color != -1); 258073f53c4aSTejun Heo 258173f53c4aSTejun Heo if (cwq->nr_in_flight[flush_color]) { 258273f53c4aSTejun Heo cwq->flush_color = flush_color; 258373f53c4aSTejun Heo atomic_inc(&wq->nr_cwqs_to_flush); 258473f53c4aSTejun Heo wait = true; 25851da177e4SLinus Torvalds } 258673f53c4aSTejun Heo } 258773f53c4aSTejun Heo 258873f53c4aSTejun Heo if (work_color >= 0) { 258973f53c4aSTejun Heo BUG_ON(work_color != work_next_color(cwq->work_color)); 259073f53c4aSTejun Heo cwq->work_color = work_color; 259173f53c4aSTejun Heo } 259273f53c4aSTejun Heo 25938b03ae3cSTejun Heo spin_unlock_irq(&gcwq->lock); 25941da177e4SLinus Torvalds } 25951da177e4SLinus Torvalds 259673f53c4aSTejun Heo if (flush_color >= 0 && atomic_dec_and_test(&wq->nr_cwqs_to_flush)) 259773f53c4aSTejun Heo complete(&wq->first_flusher->done); 259873f53c4aSTejun Heo 259973f53c4aSTejun Heo return wait; 260083c22520SOleg Nesterov } 26011da177e4SLinus Torvalds 26020fcb78c2SRolf Eike Beer /** 26031da177e4SLinus Torvalds * flush_workqueue - ensure that any scheduled work has run to completion. 26040fcb78c2SRolf Eike Beer * @wq: workqueue to flush 26051da177e4SLinus Torvalds * 26061da177e4SLinus Torvalds * Forces execution of the workqueue and blocks until its completion. 26071da177e4SLinus Torvalds * This is typically used in driver shutdown handlers. 26081da177e4SLinus Torvalds * 2609fc2e4d70SOleg Nesterov * We sleep until all works which were queued on entry have been handled, 2610fc2e4d70SOleg Nesterov * but we are not livelocked by new incoming ones. 26111da177e4SLinus Torvalds */ 26127ad5b3a5SHarvey Harrison void flush_workqueue(struct workqueue_struct *wq) 26131da177e4SLinus Torvalds { 261473f53c4aSTejun Heo struct wq_flusher this_flusher = { 261573f53c4aSTejun Heo .list = LIST_HEAD_INIT(this_flusher.list), 261673f53c4aSTejun Heo .flush_color = -1, 261773f53c4aSTejun Heo .done = COMPLETION_INITIALIZER_ONSTACK(this_flusher.done), 261873f53c4aSTejun Heo }; 261973f53c4aSTejun Heo int next_color; 2620b1f4ec17SOleg Nesterov 26213295f0efSIngo Molnar lock_map_acquire(&wq->lockdep_map); 26223295f0efSIngo Molnar lock_map_release(&wq->lockdep_map); 262373f53c4aSTejun Heo 262473f53c4aSTejun Heo mutex_lock(&wq->flush_mutex); 262573f53c4aSTejun Heo 262673f53c4aSTejun Heo /* 262773f53c4aSTejun Heo * Start-to-wait phase 262873f53c4aSTejun Heo */ 262973f53c4aSTejun Heo next_color = work_next_color(wq->work_color); 263073f53c4aSTejun Heo 263173f53c4aSTejun Heo if (next_color != wq->flush_color) { 263273f53c4aSTejun Heo /* 263373f53c4aSTejun Heo * Color space is not full. The current work_color 263473f53c4aSTejun Heo * becomes our flush_color and work_color is advanced 263573f53c4aSTejun Heo * by one. 263673f53c4aSTejun Heo */ 263773f53c4aSTejun Heo BUG_ON(!list_empty(&wq->flusher_overflow)); 263873f53c4aSTejun Heo this_flusher.flush_color = wq->work_color; 263973f53c4aSTejun Heo wq->work_color = next_color; 264073f53c4aSTejun Heo 264173f53c4aSTejun Heo if (!wq->first_flusher) { 264273f53c4aSTejun Heo /* no flush in progress, become the first flusher */ 264373f53c4aSTejun Heo BUG_ON(wq->flush_color != this_flusher.flush_color); 264473f53c4aSTejun Heo 264573f53c4aSTejun Heo wq->first_flusher = &this_flusher; 264673f53c4aSTejun Heo 264773f53c4aSTejun Heo if (!flush_workqueue_prep_cwqs(wq, wq->flush_color, 264873f53c4aSTejun Heo wq->work_color)) { 264973f53c4aSTejun Heo /* nothing to flush, done */ 265073f53c4aSTejun Heo wq->flush_color = next_color; 265173f53c4aSTejun Heo wq->first_flusher = NULL; 265273f53c4aSTejun Heo goto out_unlock; 265373f53c4aSTejun Heo } 265473f53c4aSTejun Heo } else { 265573f53c4aSTejun Heo /* wait in queue */ 265673f53c4aSTejun Heo BUG_ON(wq->flush_color == this_flusher.flush_color); 265773f53c4aSTejun Heo list_add_tail(&this_flusher.list, &wq->flusher_queue); 265873f53c4aSTejun Heo flush_workqueue_prep_cwqs(wq, -1, wq->work_color); 265973f53c4aSTejun Heo } 266073f53c4aSTejun Heo } else { 266173f53c4aSTejun Heo /* 266273f53c4aSTejun Heo * Oops, color space is full, wait on overflow queue. 266373f53c4aSTejun Heo * The next flush completion will assign us 266473f53c4aSTejun Heo * flush_color and transfer to flusher_queue. 266573f53c4aSTejun Heo */ 266673f53c4aSTejun Heo list_add_tail(&this_flusher.list, &wq->flusher_overflow); 266773f53c4aSTejun Heo } 266873f53c4aSTejun Heo 266973f53c4aSTejun Heo mutex_unlock(&wq->flush_mutex); 267073f53c4aSTejun Heo 267173f53c4aSTejun Heo wait_for_completion(&this_flusher.done); 267273f53c4aSTejun Heo 267373f53c4aSTejun Heo /* 267473f53c4aSTejun Heo * Wake-up-and-cascade phase 267573f53c4aSTejun Heo * 267673f53c4aSTejun Heo * First flushers are responsible for cascading flushes and 267773f53c4aSTejun Heo * handling overflow. Non-first flushers can simply return. 267873f53c4aSTejun Heo */ 267973f53c4aSTejun Heo if (wq->first_flusher != &this_flusher) 268073f53c4aSTejun Heo return; 268173f53c4aSTejun Heo 268273f53c4aSTejun Heo mutex_lock(&wq->flush_mutex); 268373f53c4aSTejun Heo 26844ce48b37STejun Heo /* we might have raced, check again with mutex held */ 26854ce48b37STejun Heo if (wq->first_flusher != &this_flusher) 26864ce48b37STejun Heo goto out_unlock; 26874ce48b37STejun Heo 268873f53c4aSTejun Heo wq->first_flusher = NULL; 268973f53c4aSTejun Heo 269073f53c4aSTejun Heo BUG_ON(!list_empty(&this_flusher.list)); 269173f53c4aSTejun Heo BUG_ON(wq->flush_color != this_flusher.flush_color); 269273f53c4aSTejun Heo 269373f53c4aSTejun Heo while (true) { 269473f53c4aSTejun Heo struct wq_flusher *next, *tmp; 269573f53c4aSTejun Heo 269673f53c4aSTejun Heo /* complete all the flushers sharing the current flush color */ 269773f53c4aSTejun Heo list_for_each_entry_safe(next, tmp, &wq->flusher_queue, list) { 269873f53c4aSTejun Heo if (next->flush_color != wq->flush_color) 269973f53c4aSTejun Heo break; 270073f53c4aSTejun Heo list_del_init(&next->list); 270173f53c4aSTejun Heo complete(&next->done); 270273f53c4aSTejun Heo } 270373f53c4aSTejun Heo 270473f53c4aSTejun Heo BUG_ON(!list_empty(&wq->flusher_overflow) && 270573f53c4aSTejun Heo wq->flush_color != work_next_color(wq->work_color)); 270673f53c4aSTejun Heo 270773f53c4aSTejun Heo /* this flush_color is finished, advance by one */ 270873f53c4aSTejun Heo wq->flush_color = work_next_color(wq->flush_color); 270973f53c4aSTejun Heo 271073f53c4aSTejun Heo /* one color has been freed, handle overflow queue */ 271173f53c4aSTejun Heo if (!list_empty(&wq->flusher_overflow)) { 271273f53c4aSTejun Heo /* 271373f53c4aSTejun Heo * Assign the same color to all overflowed 271473f53c4aSTejun Heo * flushers, advance work_color and append to 271573f53c4aSTejun Heo * flusher_queue. This is the start-to-wait 271673f53c4aSTejun Heo * phase for these overflowed flushers. 271773f53c4aSTejun Heo */ 271873f53c4aSTejun Heo list_for_each_entry(tmp, &wq->flusher_overflow, list) 271973f53c4aSTejun Heo tmp->flush_color = wq->work_color; 272073f53c4aSTejun Heo 272173f53c4aSTejun Heo wq->work_color = work_next_color(wq->work_color); 272273f53c4aSTejun Heo 272373f53c4aSTejun Heo list_splice_tail_init(&wq->flusher_overflow, 272473f53c4aSTejun Heo &wq->flusher_queue); 272573f53c4aSTejun Heo flush_workqueue_prep_cwqs(wq, -1, wq->work_color); 272673f53c4aSTejun Heo } 272773f53c4aSTejun Heo 272873f53c4aSTejun Heo if (list_empty(&wq->flusher_queue)) { 272973f53c4aSTejun Heo BUG_ON(wq->flush_color != wq->work_color); 273073f53c4aSTejun Heo break; 273173f53c4aSTejun Heo } 273273f53c4aSTejun Heo 273373f53c4aSTejun Heo /* 273473f53c4aSTejun Heo * Need to flush more colors. Make the next flusher 273573f53c4aSTejun Heo * the new first flusher and arm cwqs. 273673f53c4aSTejun Heo */ 273773f53c4aSTejun Heo BUG_ON(wq->flush_color == wq->work_color); 273873f53c4aSTejun Heo BUG_ON(wq->flush_color != next->flush_color); 273973f53c4aSTejun Heo 274073f53c4aSTejun Heo list_del_init(&next->list); 274173f53c4aSTejun Heo wq->first_flusher = next; 274273f53c4aSTejun Heo 274373f53c4aSTejun Heo if (flush_workqueue_prep_cwqs(wq, wq->flush_color, -1)) 274473f53c4aSTejun Heo break; 274573f53c4aSTejun Heo 274673f53c4aSTejun Heo /* 274773f53c4aSTejun Heo * Meh... this color is already done, clear first 274873f53c4aSTejun Heo * flusher and repeat cascading. 274973f53c4aSTejun Heo */ 275073f53c4aSTejun Heo wq->first_flusher = NULL; 275173f53c4aSTejun Heo } 275273f53c4aSTejun Heo 275373f53c4aSTejun Heo out_unlock: 275473f53c4aSTejun Heo mutex_unlock(&wq->flush_mutex); 27551da177e4SLinus Torvalds } 2756ae90dd5dSDave Jones EXPORT_SYMBOL_GPL(flush_workqueue); 27571da177e4SLinus Torvalds 27589c5a2ba7STejun Heo /** 27599c5a2ba7STejun Heo * drain_workqueue - drain a workqueue 27609c5a2ba7STejun Heo * @wq: workqueue to drain 27619c5a2ba7STejun Heo * 27629c5a2ba7STejun Heo * Wait until the workqueue becomes empty. While draining is in progress, 27639c5a2ba7STejun Heo * only chain queueing is allowed. IOW, only currently pending or running 27649c5a2ba7STejun Heo * work items on @wq can queue further work items on it. @wq is flushed 27659c5a2ba7STejun Heo * repeatedly until it becomes empty. The number of flushing is detemined 27669c5a2ba7STejun Heo * by the depth of chaining and should be relatively short. Whine if it 27679c5a2ba7STejun Heo * takes too long. 27689c5a2ba7STejun Heo */ 27699c5a2ba7STejun Heo void drain_workqueue(struct workqueue_struct *wq) 27709c5a2ba7STejun Heo { 27719c5a2ba7STejun Heo unsigned int flush_cnt = 0; 27729c5a2ba7STejun Heo unsigned int cpu; 27739c5a2ba7STejun Heo 27749c5a2ba7STejun Heo /* 27759c5a2ba7STejun Heo * __queue_work() needs to test whether there are drainers, is much 27769c5a2ba7STejun Heo * hotter than drain_workqueue() and already looks at @wq->flags. 27779c5a2ba7STejun Heo * Use WQ_DRAINING so that queue doesn't have to check nr_drainers. 27789c5a2ba7STejun Heo */ 27799c5a2ba7STejun Heo spin_lock(&workqueue_lock); 27809c5a2ba7STejun Heo if (!wq->nr_drainers++) 27819c5a2ba7STejun Heo wq->flags |= WQ_DRAINING; 27829c5a2ba7STejun Heo spin_unlock(&workqueue_lock); 27839c5a2ba7STejun Heo reflush: 27849c5a2ba7STejun Heo flush_workqueue(wq); 27859c5a2ba7STejun Heo 27869c5a2ba7STejun Heo for_each_cwq_cpu(cpu, wq) { 27879c5a2ba7STejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 2788fa2563e4SThomas Tuttle bool drained; 27899c5a2ba7STejun Heo 2790bd7bdd43STejun Heo spin_lock_irq(&cwq->pool->gcwq->lock); 2791fa2563e4SThomas Tuttle drained = !cwq->nr_active && list_empty(&cwq->delayed_works); 2792bd7bdd43STejun Heo spin_unlock_irq(&cwq->pool->gcwq->lock); 2793fa2563e4SThomas Tuttle 2794fa2563e4SThomas Tuttle if (drained) 27959c5a2ba7STejun Heo continue; 27969c5a2ba7STejun Heo 27979c5a2ba7STejun Heo if (++flush_cnt == 10 || 27989c5a2ba7STejun Heo (flush_cnt % 100 == 0 && flush_cnt <= 1000)) 2799044c782cSValentin Ilie pr_warn("workqueue %s: flush on destruction isn't complete after %u tries\n", 28009c5a2ba7STejun Heo wq->name, flush_cnt); 28019c5a2ba7STejun Heo goto reflush; 28029c5a2ba7STejun Heo } 28039c5a2ba7STejun Heo 28049c5a2ba7STejun Heo spin_lock(&workqueue_lock); 28059c5a2ba7STejun Heo if (!--wq->nr_drainers) 28069c5a2ba7STejun Heo wq->flags &= ~WQ_DRAINING; 28079c5a2ba7STejun Heo spin_unlock(&workqueue_lock); 28089c5a2ba7STejun Heo } 28099c5a2ba7STejun Heo EXPORT_SYMBOL_GPL(drain_workqueue); 28109c5a2ba7STejun Heo 2811606a5020STejun Heo static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr) 2812baf59022STejun Heo { 2813baf59022STejun Heo struct worker *worker = NULL; 2814baf59022STejun Heo struct global_cwq *gcwq; 2815baf59022STejun Heo struct cpu_workqueue_struct *cwq; 2816baf59022STejun Heo 2817baf59022STejun Heo might_sleep(); 2818baf59022STejun Heo gcwq = get_work_gcwq(work); 2819baf59022STejun Heo if (!gcwq) 2820baf59022STejun Heo return false; 2821baf59022STejun Heo 2822baf59022STejun Heo spin_lock_irq(&gcwq->lock); 2823baf59022STejun Heo if (!list_empty(&work->entry)) { 2824baf59022STejun Heo /* 2825baf59022STejun Heo * See the comment near try_to_grab_pending()->smp_rmb(). 2826baf59022STejun Heo * If it was re-queued to a different gcwq under us, we 2827baf59022STejun Heo * are not going to wait. 2828baf59022STejun Heo */ 2829baf59022STejun Heo smp_rmb(); 2830baf59022STejun Heo cwq = get_work_cwq(work); 2831bd7bdd43STejun Heo if (unlikely(!cwq || gcwq != cwq->pool->gcwq)) 2832baf59022STejun Heo goto already_gone; 2833606a5020STejun Heo } else { 2834baf59022STejun Heo worker = find_worker_executing_work(gcwq, work); 2835baf59022STejun Heo if (!worker) 2836baf59022STejun Heo goto already_gone; 2837baf59022STejun Heo cwq = worker->current_cwq; 2838606a5020STejun Heo } 2839baf59022STejun Heo 2840baf59022STejun Heo insert_wq_barrier(cwq, barr, work, worker); 2841baf59022STejun Heo spin_unlock_irq(&gcwq->lock); 2842baf59022STejun Heo 2843e159489bSTejun Heo /* 2844e159489bSTejun Heo * If @max_active is 1 or rescuer is in use, flushing another work 2845e159489bSTejun Heo * item on the same workqueue may lead to deadlock. Make sure the 2846e159489bSTejun Heo * flusher is not running on the same workqueue by verifying write 2847e159489bSTejun Heo * access. 2848e159489bSTejun Heo */ 2849e159489bSTejun Heo if (cwq->wq->saved_max_active == 1 || cwq->wq->flags & WQ_RESCUER) 2850baf59022STejun Heo lock_map_acquire(&cwq->wq->lockdep_map); 2851e159489bSTejun Heo else 2852e159489bSTejun Heo lock_map_acquire_read(&cwq->wq->lockdep_map); 2853baf59022STejun Heo lock_map_release(&cwq->wq->lockdep_map); 2854e159489bSTejun Heo 2855baf59022STejun Heo return true; 2856baf59022STejun Heo already_gone: 2857baf59022STejun Heo spin_unlock_irq(&gcwq->lock); 2858baf59022STejun Heo return false; 2859baf59022STejun Heo } 2860baf59022STejun Heo 2861db700897SOleg Nesterov /** 2862401a8d04STejun Heo * flush_work - wait for a work to finish executing the last queueing instance 2863401a8d04STejun Heo * @work: the work to flush 2864db700897SOleg Nesterov * 2865606a5020STejun Heo * Wait until @work has finished execution. @work is guaranteed to be idle 2866606a5020STejun Heo * on return if it hasn't been requeued since flush started. 2867401a8d04STejun Heo * 2868401a8d04STejun Heo * RETURNS: 2869401a8d04STejun Heo * %true if flush_work() waited for the work to finish execution, 2870401a8d04STejun Heo * %false if it was already idle. 2871db700897SOleg Nesterov */ 2872401a8d04STejun Heo bool flush_work(struct work_struct *work) 2873db700897SOleg Nesterov { 2874db700897SOleg Nesterov struct wq_barrier barr; 2875db700897SOleg Nesterov 28760976dfc1SStephen Boyd lock_map_acquire(&work->lockdep_map); 28770976dfc1SStephen Boyd lock_map_release(&work->lockdep_map); 28780976dfc1SStephen Boyd 2879606a5020STejun Heo if (start_flush_work(work, &barr)) { 2880db700897SOleg Nesterov wait_for_completion(&barr.done); 2881dc186ad7SThomas Gleixner destroy_work_on_stack(&barr.work); 2882401a8d04STejun Heo return true; 2883606a5020STejun Heo } else { 2884401a8d04STejun Heo return false; 2885db700897SOleg Nesterov } 2886606a5020STejun Heo } 2887db700897SOleg Nesterov EXPORT_SYMBOL_GPL(flush_work); 2888db700897SOleg Nesterov 288936e227d2STejun Heo static bool __cancel_work_timer(struct work_struct *work, bool is_dwork) 2890401a8d04STejun Heo { 2891bbb68dfaSTejun Heo unsigned long flags; 28921f1f642eSOleg Nesterov int ret; 28931f1f642eSOleg Nesterov 28941f1f642eSOleg Nesterov do { 2895bbb68dfaSTejun Heo ret = try_to_grab_pending(work, is_dwork, &flags); 2896bbb68dfaSTejun Heo /* 2897bbb68dfaSTejun Heo * If someone else is canceling, wait for the same event it 2898bbb68dfaSTejun Heo * would be waiting for before retrying. 2899bbb68dfaSTejun Heo */ 2900bbb68dfaSTejun Heo if (unlikely(ret == -ENOENT)) 2901606a5020STejun Heo flush_work(work); 29021f1f642eSOleg Nesterov } while (unlikely(ret < 0)); 29031f1f642eSOleg Nesterov 2904bbb68dfaSTejun Heo /* tell other tasks trying to grab @work to back off */ 2905bbb68dfaSTejun Heo mark_work_canceling(work); 2906bbb68dfaSTejun Heo local_irq_restore(flags); 2907bbb68dfaSTejun Heo 2908606a5020STejun Heo flush_work(work); 29097a22ad75STejun Heo clear_work_data(work); 29101f1f642eSOleg Nesterov return ret; 29111f1f642eSOleg Nesterov } 29121f1f642eSOleg Nesterov 29136e84d644SOleg Nesterov /** 2914401a8d04STejun Heo * cancel_work_sync - cancel a work and wait for it to finish 2915401a8d04STejun Heo * @work: the work to cancel 29166e84d644SOleg Nesterov * 2917401a8d04STejun Heo * Cancel @work and wait for its execution to finish. This function 2918401a8d04STejun Heo * can be used even if the work re-queues itself or migrates to 2919401a8d04STejun Heo * another workqueue. On return from this function, @work is 2920401a8d04STejun Heo * guaranteed to be not pending or executing on any CPU. 29211f1f642eSOleg Nesterov * 2922401a8d04STejun Heo * cancel_work_sync(&delayed_work->work) must not be used for 2923401a8d04STejun Heo * delayed_work's. Use cancel_delayed_work_sync() instead. 29246e84d644SOleg Nesterov * 2925401a8d04STejun Heo * The caller must ensure that the workqueue on which @work was last 29266e84d644SOleg Nesterov * queued can't be destroyed before this function returns. 2927401a8d04STejun Heo * 2928401a8d04STejun Heo * RETURNS: 2929401a8d04STejun Heo * %true if @work was pending, %false otherwise. 29306e84d644SOleg Nesterov */ 2931401a8d04STejun Heo bool cancel_work_sync(struct work_struct *work) 29326e84d644SOleg Nesterov { 293336e227d2STejun Heo return __cancel_work_timer(work, false); 2934b89deed3SOleg Nesterov } 293528e53bddSOleg Nesterov EXPORT_SYMBOL_GPL(cancel_work_sync); 2936b89deed3SOleg Nesterov 29376e84d644SOleg Nesterov /** 2938401a8d04STejun Heo * flush_delayed_work - wait for a dwork to finish executing the last queueing 2939401a8d04STejun Heo * @dwork: the delayed work to flush 29406e84d644SOleg Nesterov * 2941401a8d04STejun Heo * Delayed timer is cancelled and the pending work is queued for 2942401a8d04STejun Heo * immediate execution. Like flush_work(), this function only 2943401a8d04STejun Heo * considers the last queueing instance of @dwork. 29441f1f642eSOleg Nesterov * 2945401a8d04STejun Heo * RETURNS: 2946401a8d04STejun Heo * %true if flush_work() waited for the work to finish execution, 2947401a8d04STejun Heo * %false if it was already idle. 29486e84d644SOleg Nesterov */ 2949401a8d04STejun Heo bool flush_delayed_work(struct delayed_work *dwork) 2950401a8d04STejun Heo { 29518930cabaSTejun Heo local_irq_disable(); 2952401a8d04STejun Heo if (del_timer_sync(&dwork->timer)) 29531265057fSTejun Heo __queue_work(dwork->cpu, 2954401a8d04STejun Heo get_work_cwq(&dwork->work)->wq, &dwork->work); 29558930cabaSTejun Heo local_irq_enable(); 2956401a8d04STejun Heo return flush_work(&dwork->work); 2957401a8d04STejun Heo } 2958401a8d04STejun Heo EXPORT_SYMBOL(flush_delayed_work); 2959401a8d04STejun Heo 2960401a8d04STejun Heo /** 296157b30ae7STejun Heo * cancel_delayed_work - cancel a delayed work 296257b30ae7STejun Heo * @dwork: delayed_work to cancel 296309383498STejun Heo * 296457b30ae7STejun Heo * Kill off a pending delayed_work. Returns %true if @dwork was pending 296557b30ae7STejun Heo * and canceled; %false if wasn't pending. Note that the work callback 296657b30ae7STejun Heo * function may still be running on return, unless it returns %true and the 296757b30ae7STejun Heo * work doesn't re-arm itself. Explicitly flush or use 296857b30ae7STejun Heo * cancel_delayed_work_sync() to wait on it. 296909383498STejun Heo * 297057b30ae7STejun Heo * This function is safe to call from any context including IRQ handler. 297109383498STejun Heo */ 297257b30ae7STejun Heo bool cancel_delayed_work(struct delayed_work *dwork) 297309383498STejun Heo { 297457b30ae7STejun Heo unsigned long flags; 297557b30ae7STejun Heo int ret; 297657b30ae7STejun Heo 297757b30ae7STejun Heo do { 297857b30ae7STejun Heo ret = try_to_grab_pending(&dwork->work, true, &flags); 297957b30ae7STejun Heo } while (unlikely(ret == -EAGAIN)); 298057b30ae7STejun Heo 298157b30ae7STejun Heo if (unlikely(ret < 0)) 298257b30ae7STejun Heo return false; 298357b30ae7STejun Heo 298457b30ae7STejun Heo set_work_cpu_and_clear_pending(&dwork->work, work_cpu(&dwork->work)); 298557b30ae7STejun Heo local_irq_restore(flags); 2986c0158ca6SDan Magenheimer return ret; 298709383498STejun Heo } 298857b30ae7STejun Heo EXPORT_SYMBOL(cancel_delayed_work); 298909383498STejun Heo 299009383498STejun Heo /** 2991401a8d04STejun Heo * cancel_delayed_work_sync - cancel a delayed work and wait for it to finish 2992401a8d04STejun Heo * @dwork: the delayed work cancel 2993401a8d04STejun Heo * 2994401a8d04STejun Heo * This is cancel_work_sync() for delayed works. 2995401a8d04STejun Heo * 2996401a8d04STejun Heo * RETURNS: 2997401a8d04STejun Heo * %true if @dwork was pending, %false otherwise. 2998401a8d04STejun Heo */ 2999401a8d04STejun Heo bool cancel_delayed_work_sync(struct delayed_work *dwork) 30006e84d644SOleg Nesterov { 300136e227d2STejun Heo return __cancel_work_timer(&dwork->work, true); 30026e84d644SOleg Nesterov } 3003f5a421a4SOleg Nesterov EXPORT_SYMBOL(cancel_delayed_work_sync); 30041da177e4SLinus Torvalds 30050fcb78c2SRolf Eike Beer /** 3006c1a220e7SZhang Rui * schedule_work_on - put work task on a specific cpu 3007c1a220e7SZhang Rui * @cpu: cpu to put the work task on 3008c1a220e7SZhang Rui * @work: job to be done 3009c1a220e7SZhang Rui * 3010c1a220e7SZhang Rui * This puts a job on a specific cpu 3011c1a220e7SZhang Rui */ 3012d4283e93STejun Heo bool schedule_work_on(int cpu, struct work_struct *work) 3013c1a220e7SZhang Rui { 3014d320c038STejun Heo return queue_work_on(cpu, system_wq, work); 3015c1a220e7SZhang Rui } 3016c1a220e7SZhang Rui EXPORT_SYMBOL(schedule_work_on); 3017c1a220e7SZhang Rui 30180fcb78c2SRolf Eike Beer /** 3019ae90dd5dSDave Jones * schedule_work - put work task in global workqueue 30201da177e4SLinus Torvalds * @work: job to be done 30211da177e4SLinus Torvalds * 3022d4283e93STejun Heo * Returns %false if @work was already on the kernel-global workqueue and 3023d4283e93STejun Heo * %true otherwise. 302452bad64dSDavid Howells * 30250fcb78c2SRolf Eike Beer * This puts a job in the kernel-global workqueue if it was not already 30260fcb78c2SRolf Eike Beer * queued and leaves it in the same position on the kernel-global 30270fcb78c2SRolf Eike Beer * workqueue otherwise. 30281da177e4SLinus Torvalds */ 3029d4283e93STejun Heo bool schedule_work(struct work_struct *work) 30301da177e4SLinus Torvalds { 30310fcb78c2SRolf Eike Beer return queue_work(system_wq, work); 30321da177e4SLinus Torvalds } 30330fcb78c2SRolf Eike Beer EXPORT_SYMBOL(schedule_work); 30341da177e4SLinus Torvalds 30350fcb78c2SRolf Eike Beer /** 30360fcb78c2SRolf Eike Beer * schedule_delayed_work_on - queue work in global workqueue on CPU after delay 30370fcb78c2SRolf Eike Beer * @cpu: cpu to use 30380fcb78c2SRolf Eike Beer * @dwork: job to be done 30390fcb78c2SRolf Eike Beer * @delay: number of jiffies to wait 30400fcb78c2SRolf Eike Beer * 30410fcb78c2SRolf Eike Beer * After waiting for a given time this puts a job in the kernel-global 30420fcb78c2SRolf Eike Beer * workqueue on the specified CPU. 30430fcb78c2SRolf Eike Beer */ 3044d4283e93STejun Heo bool schedule_delayed_work_on(int cpu, struct delayed_work *dwork, 3045d4283e93STejun Heo unsigned long delay) 30461da177e4SLinus Torvalds { 3047d320c038STejun Heo return queue_delayed_work_on(cpu, system_wq, dwork, delay); 30481da177e4SLinus Torvalds } 3049ae90dd5dSDave Jones EXPORT_SYMBOL(schedule_delayed_work_on); 30501da177e4SLinus Torvalds 3051b6136773SAndrew Morton /** 30520a13c00eSTejun Heo * schedule_delayed_work - put work task in global workqueue after delay 30530a13c00eSTejun Heo * @dwork: job to be done 30540a13c00eSTejun Heo * @delay: number of jiffies to wait or 0 for immediate execution 30550a13c00eSTejun Heo * 30560a13c00eSTejun Heo * After waiting for a given time this puts a job in the kernel-global 30570a13c00eSTejun Heo * workqueue. 30580a13c00eSTejun Heo */ 3059d4283e93STejun Heo bool schedule_delayed_work(struct delayed_work *dwork, unsigned long delay) 30600a13c00eSTejun Heo { 30610a13c00eSTejun Heo return queue_delayed_work(system_wq, dwork, delay); 30620a13c00eSTejun Heo } 30630a13c00eSTejun Heo EXPORT_SYMBOL(schedule_delayed_work); 30640a13c00eSTejun Heo 30650a13c00eSTejun Heo /** 306631ddd871STejun Heo * schedule_on_each_cpu - execute a function synchronously on each online CPU 3067b6136773SAndrew Morton * @func: the function to call 3068b6136773SAndrew Morton * 306931ddd871STejun Heo * schedule_on_each_cpu() executes @func on each online CPU using the 307031ddd871STejun Heo * system workqueue and blocks until all CPUs have completed. 3071b6136773SAndrew Morton * schedule_on_each_cpu() is very slow. 307231ddd871STejun Heo * 307331ddd871STejun Heo * RETURNS: 307431ddd871STejun Heo * 0 on success, -errno on failure. 3075b6136773SAndrew Morton */ 307665f27f38SDavid Howells int schedule_on_each_cpu(work_func_t func) 307715316ba8SChristoph Lameter { 307815316ba8SChristoph Lameter int cpu; 307938f51568SNamhyung Kim struct work_struct __percpu *works; 308015316ba8SChristoph Lameter 3081b6136773SAndrew Morton works = alloc_percpu(struct work_struct); 3082b6136773SAndrew Morton if (!works) 308315316ba8SChristoph Lameter return -ENOMEM; 3084b6136773SAndrew Morton 308595402b38SGautham R Shenoy get_online_cpus(); 308693981800STejun Heo 308715316ba8SChristoph Lameter for_each_online_cpu(cpu) { 30889bfb1839SIngo Molnar struct work_struct *work = per_cpu_ptr(works, cpu); 30899bfb1839SIngo Molnar 30909bfb1839SIngo Molnar INIT_WORK(work, func); 30918de6d308SOleg Nesterov schedule_work_on(cpu, work); 309215316ba8SChristoph Lameter } 309393981800STejun Heo 309493981800STejun Heo for_each_online_cpu(cpu) 30958616a89aSOleg Nesterov flush_work(per_cpu_ptr(works, cpu)); 309693981800STejun Heo 309795402b38SGautham R Shenoy put_online_cpus(); 3098b6136773SAndrew Morton free_percpu(works); 309915316ba8SChristoph Lameter return 0; 310015316ba8SChristoph Lameter } 310115316ba8SChristoph Lameter 3102eef6a7d5SAlan Stern /** 3103eef6a7d5SAlan Stern * flush_scheduled_work - ensure that any scheduled work has run to completion. 3104eef6a7d5SAlan Stern * 3105eef6a7d5SAlan Stern * Forces execution of the kernel-global workqueue and blocks until its 3106eef6a7d5SAlan Stern * completion. 3107eef6a7d5SAlan Stern * 3108eef6a7d5SAlan Stern * Think twice before calling this function! It's very easy to get into 3109eef6a7d5SAlan Stern * trouble if you don't take great care. Either of the following situations 3110eef6a7d5SAlan Stern * will lead to deadlock: 3111eef6a7d5SAlan Stern * 3112eef6a7d5SAlan Stern * One of the work items currently on the workqueue needs to acquire 3113eef6a7d5SAlan Stern * a lock held by your code or its caller. 3114eef6a7d5SAlan Stern * 3115eef6a7d5SAlan Stern * Your code is running in the context of a work routine. 3116eef6a7d5SAlan Stern * 3117eef6a7d5SAlan Stern * They will be detected by lockdep when they occur, but the first might not 3118eef6a7d5SAlan Stern * occur very often. It depends on what work items are on the workqueue and 3119eef6a7d5SAlan Stern * what locks they need, which you have no control over. 3120eef6a7d5SAlan Stern * 3121eef6a7d5SAlan Stern * In most situations flushing the entire workqueue is overkill; you merely 3122eef6a7d5SAlan Stern * need to know that a particular work item isn't queued and isn't running. 3123eef6a7d5SAlan Stern * In such cases you should use cancel_delayed_work_sync() or 3124eef6a7d5SAlan Stern * cancel_work_sync() instead. 3125eef6a7d5SAlan Stern */ 31261da177e4SLinus Torvalds void flush_scheduled_work(void) 31271da177e4SLinus Torvalds { 3128d320c038STejun Heo flush_workqueue(system_wq); 31291da177e4SLinus Torvalds } 3130ae90dd5dSDave Jones EXPORT_SYMBOL(flush_scheduled_work); 31311da177e4SLinus Torvalds 31321da177e4SLinus Torvalds /** 31331fa44ecaSJames Bottomley * execute_in_process_context - reliably execute the routine with user context 31341fa44ecaSJames Bottomley * @fn: the function to execute 31351fa44ecaSJames Bottomley * @ew: guaranteed storage for the execute work structure (must 31361fa44ecaSJames Bottomley * be available when the work executes) 31371fa44ecaSJames Bottomley * 31381fa44ecaSJames Bottomley * Executes the function immediately if process context is available, 31391fa44ecaSJames Bottomley * otherwise schedules the function for delayed execution. 31401fa44ecaSJames Bottomley * 31411fa44ecaSJames Bottomley * Returns: 0 - function was executed 31421fa44ecaSJames Bottomley * 1 - function was scheduled for execution 31431fa44ecaSJames Bottomley */ 314465f27f38SDavid Howells int execute_in_process_context(work_func_t fn, struct execute_work *ew) 31451fa44ecaSJames Bottomley { 31461fa44ecaSJames Bottomley if (!in_interrupt()) { 314765f27f38SDavid Howells fn(&ew->work); 31481fa44ecaSJames Bottomley return 0; 31491fa44ecaSJames Bottomley } 31501fa44ecaSJames Bottomley 315165f27f38SDavid Howells INIT_WORK(&ew->work, fn); 31521fa44ecaSJames Bottomley schedule_work(&ew->work); 31531fa44ecaSJames Bottomley 31541fa44ecaSJames Bottomley return 1; 31551fa44ecaSJames Bottomley } 31561fa44ecaSJames Bottomley EXPORT_SYMBOL_GPL(execute_in_process_context); 31571fa44ecaSJames Bottomley 31581da177e4SLinus Torvalds int keventd_up(void) 31591da177e4SLinus Torvalds { 3160d320c038STejun Heo return system_wq != NULL; 31611da177e4SLinus Torvalds } 31621da177e4SLinus Torvalds 3163bdbc5dd7STejun Heo static int alloc_cwqs(struct workqueue_struct *wq) 31641da177e4SLinus Torvalds { 31653af24433SOleg Nesterov /* 31660f900049STejun Heo * cwqs are forced aligned according to WORK_STRUCT_FLAG_BITS. 31670f900049STejun Heo * Make sure that the alignment isn't lower than that of 31680f900049STejun Heo * unsigned long long. 31693af24433SOleg Nesterov */ 31700f900049STejun Heo const size_t size = sizeof(struct cpu_workqueue_struct); 31710f900049STejun Heo const size_t align = max_t(size_t, 1 << WORK_STRUCT_FLAG_BITS, 31720f900049STejun Heo __alignof__(unsigned long long)); 31733af24433SOleg Nesterov 3174e06ffa1eSLai Jiangshan if (!(wq->flags & WQ_UNBOUND)) 3175f3421797STejun Heo wq->cpu_wq.pcpu = __alloc_percpu(size, align); 3176931ac77eSTejun Heo else { 31770f900049STejun Heo void *ptr; 3178e1d8aa9fSFrederic Weisbecker 31790f900049STejun Heo /* 3180f3421797STejun Heo * Allocate enough room to align cwq and put an extra 3181f3421797STejun Heo * pointer at the end pointing back to the originally 3182f3421797STejun Heo * allocated pointer which will be used for free. 31830f900049STejun Heo */ 3184bdbc5dd7STejun Heo ptr = kzalloc(size + align + sizeof(void *), GFP_KERNEL); 3185bdbc5dd7STejun Heo if (ptr) { 3186bdbc5dd7STejun Heo wq->cpu_wq.single = PTR_ALIGN(ptr, align); 3187bdbc5dd7STejun Heo *(void **)(wq->cpu_wq.single + 1) = ptr; 3188bdbc5dd7STejun Heo } 31893af24433SOleg Nesterov } 31903af24433SOleg Nesterov 31910415b00dSTejun Heo /* just in case, make sure it's actually aligned */ 3192bdbc5dd7STejun Heo BUG_ON(!IS_ALIGNED(wq->cpu_wq.v, align)); 3193bdbc5dd7STejun Heo return wq->cpu_wq.v ? 0 : -ENOMEM; 31940f900049STejun Heo } 31950f900049STejun Heo 3196bdbc5dd7STejun Heo static void free_cwqs(struct workqueue_struct *wq) 319706ba38a9SOleg Nesterov { 3198e06ffa1eSLai Jiangshan if (!(wq->flags & WQ_UNBOUND)) 3199bdbc5dd7STejun Heo free_percpu(wq->cpu_wq.pcpu); 3200f3421797STejun Heo else if (wq->cpu_wq.single) { 3201f3421797STejun Heo /* the pointer to free is stored right after the cwq */ 3202f3421797STejun Heo kfree(*(void **)(wq->cpu_wq.single + 1)); 320306ba38a9SOleg Nesterov } 320406ba38a9SOleg Nesterov } 320506ba38a9SOleg Nesterov 3206f3421797STejun Heo static int wq_clamp_max_active(int max_active, unsigned int flags, 3207f3421797STejun Heo const char *name) 3208b71ab8c2STejun Heo { 3209f3421797STejun Heo int lim = flags & WQ_UNBOUND ? WQ_UNBOUND_MAX_ACTIVE : WQ_MAX_ACTIVE; 3210f3421797STejun Heo 3211f3421797STejun Heo if (max_active < 1 || max_active > lim) 3212044c782cSValentin Ilie pr_warn("workqueue: max_active %d requested for %s is out of range, clamping between %d and %d\n", 3213f3421797STejun Heo max_active, name, 1, lim); 3214b71ab8c2STejun Heo 3215f3421797STejun Heo return clamp_val(max_active, 1, lim); 3216b71ab8c2STejun Heo } 3217b71ab8c2STejun Heo 3218b196be89STejun Heo struct workqueue_struct *__alloc_workqueue_key(const char *fmt, 321997e37d7bSTejun Heo unsigned int flags, 32201e19ffc6STejun Heo int max_active, 3221eb13ba87SJohannes Berg struct lock_class_key *key, 3222b196be89STejun Heo const char *lock_name, ...) 32233af24433SOleg Nesterov { 3224b196be89STejun Heo va_list args, args1; 32253af24433SOleg Nesterov struct workqueue_struct *wq; 3226c34056a3STejun Heo unsigned int cpu; 3227b196be89STejun Heo size_t namelen; 3228b196be89STejun Heo 3229b196be89STejun Heo /* determine namelen, allocate wq and format name */ 3230b196be89STejun Heo va_start(args, lock_name); 3231b196be89STejun Heo va_copy(args1, args); 3232b196be89STejun Heo namelen = vsnprintf(NULL, 0, fmt, args) + 1; 3233b196be89STejun Heo 3234b196be89STejun Heo wq = kzalloc(sizeof(*wq) + namelen, GFP_KERNEL); 3235b196be89STejun Heo if (!wq) 3236b196be89STejun Heo goto err; 3237b196be89STejun Heo 3238b196be89STejun Heo vsnprintf(wq->name, namelen, fmt, args1); 3239b196be89STejun Heo va_end(args); 3240b196be89STejun Heo va_end(args1); 32413af24433SOleg Nesterov 3242f3421797STejun Heo /* 32436370a6adSTejun Heo * Workqueues which may be used during memory reclaim should 32446370a6adSTejun Heo * have a rescuer to guarantee forward progress. 32456370a6adSTejun Heo */ 32466370a6adSTejun Heo if (flags & WQ_MEM_RECLAIM) 32476370a6adSTejun Heo flags |= WQ_RESCUER; 32486370a6adSTejun Heo 3249d320c038STejun Heo max_active = max_active ?: WQ_DFL_ACTIVE; 3250b196be89STejun Heo max_active = wq_clamp_max_active(max_active, flags, wq->name); 32513af24433SOleg Nesterov 3252b196be89STejun Heo /* init wq */ 325397e37d7bSTejun Heo wq->flags = flags; 3254a0a1a5fdSTejun Heo wq->saved_max_active = max_active; 325573f53c4aSTejun Heo mutex_init(&wq->flush_mutex); 325673f53c4aSTejun Heo atomic_set(&wq->nr_cwqs_to_flush, 0); 325773f53c4aSTejun Heo INIT_LIST_HEAD(&wq->flusher_queue); 325873f53c4aSTejun Heo INIT_LIST_HEAD(&wq->flusher_overflow); 32593af24433SOleg Nesterov 3260eb13ba87SJohannes Berg lockdep_init_map(&wq->lockdep_map, lock_name, key, 0); 3261cce1a165SOleg Nesterov INIT_LIST_HEAD(&wq->list); 32623af24433SOleg Nesterov 3263bdbc5dd7STejun Heo if (alloc_cwqs(wq) < 0) 3264bdbc5dd7STejun Heo goto err; 3265bdbc5dd7STejun Heo 3266f3421797STejun Heo for_each_cwq_cpu(cpu, wq) { 32671537663fSTejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 32688b03ae3cSTejun Heo struct global_cwq *gcwq = get_gcwq(cpu); 32693270476aSTejun Heo int pool_idx = (bool)(flags & WQ_HIGHPRI); 32701537663fSTejun Heo 32710f900049STejun Heo BUG_ON((unsigned long)cwq & WORK_STRUCT_FLAG_MASK); 32723270476aSTejun Heo cwq->pool = &gcwq->pools[pool_idx]; 3273c34056a3STejun Heo cwq->wq = wq; 327473f53c4aSTejun Heo cwq->flush_color = -1; 32751e19ffc6STejun Heo cwq->max_active = max_active; 32761e19ffc6STejun Heo INIT_LIST_HEAD(&cwq->delayed_works); 3277e22bee78STejun Heo } 32781537663fSTejun Heo 3279e22bee78STejun Heo if (flags & WQ_RESCUER) { 3280e22bee78STejun Heo struct worker *rescuer; 3281e22bee78STejun Heo 3282f2e005aaSTejun Heo if (!alloc_mayday_mask(&wq->mayday_mask, GFP_KERNEL)) 3283e22bee78STejun Heo goto err; 3284e22bee78STejun Heo 3285e22bee78STejun Heo wq->rescuer = rescuer = alloc_worker(); 3286e22bee78STejun Heo if (!rescuer) 3287e22bee78STejun Heo goto err; 3288e22bee78STejun Heo 3289111c225aSTejun Heo rescuer->rescue_wq = wq; 3290111c225aSTejun Heo rescuer->task = kthread_create(rescuer_thread, rescuer, "%s", 3291b196be89STejun Heo wq->name); 3292e22bee78STejun Heo if (IS_ERR(rescuer->task)) 3293e22bee78STejun Heo goto err; 3294e22bee78STejun Heo 3295e22bee78STejun Heo rescuer->task->flags |= PF_THREAD_BOUND; 3296e22bee78STejun Heo wake_up_process(rescuer->task); 32973af24433SOleg Nesterov } 32981537663fSTejun Heo 32993af24433SOleg Nesterov /* 3300a0a1a5fdSTejun Heo * workqueue_lock protects global freeze state and workqueues 3301a0a1a5fdSTejun Heo * list. Grab it, set max_active accordingly and add the new 3302a0a1a5fdSTejun Heo * workqueue to workqueues list. 33033af24433SOleg Nesterov */ 33043af24433SOleg Nesterov spin_lock(&workqueue_lock); 3305a0a1a5fdSTejun Heo 330658a69cb4STejun Heo if (workqueue_freezing && wq->flags & WQ_FREEZABLE) 3307f3421797STejun Heo for_each_cwq_cpu(cpu, wq) 3308a0a1a5fdSTejun Heo get_cwq(cpu, wq)->max_active = 0; 3309a0a1a5fdSTejun Heo 33103af24433SOleg Nesterov list_add(&wq->list, &workqueues); 3311a0a1a5fdSTejun Heo 33123af24433SOleg Nesterov spin_unlock(&workqueue_lock); 33133af24433SOleg Nesterov 33143af24433SOleg Nesterov return wq; 33154690c4abSTejun Heo err: 33164690c4abSTejun Heo if (wq) { 3317bdbc5dd7STejun Heo free_cwqs(wq); 3318f2e005aaSTejun Heo free_mayday_mask(wq->mayday_mask); 3319e22bee78STejun Heo kfree(wq->rescuer); 33204690c4abSTejun Heo kfree(wq); 33213af24433SOleg Nesterov } 33224690c4abSTejun Heo return NULL; 33231da177e4SLinus Torvalds } 3324d320c038STejun Heo EXPORT_SYMBOL_GPL(__alloc_workqueue_key); 33251da177e4SLinus Torvalds 33263af24433SOleg Nesterov /** 33273af24433SOleg Nesterov * destroy_workqueue - safely terminate a workqueue 33283af24433SOleg Nesterov * @wq: target workqueue 33293af24433SOleg Nesterov * 33303af24433SOleg Nesterov * Safely destroy a workqueue. All work currently pending will be done first. 33313af24433SOleg Nesterov */ 33323af24433SOleg Nesterov void destroy_workqueue(struct workqueue_struct *wq) 33333af24433SOleg Nesterov { 3334c8e55f36STejun Heo unsigned int cpu; 33353af24433SOleg Nesterov 33369c5a2ba7STejun Heo /* drain it before proceeding with destruction */ 33379c5a2ba7STejun Heo drain_workqueue(wq); 3338c8efcc25STejun Heo 3339a0a1a5fdSTejun Heo /* 3340a0a1a5fdSTejun Heo * wq list is used to freeze wq, remove from list after 3341a0a1a5fdSTejun Heo * flushing is complete in case freeze races us. 3342a0a1a5fdSTejun Heo */ 334395402b38SGautham R Shenoy spin_lock(&workqueue_lock); 33443af24433SOleg Nesterov list_del(&wq->list); 334595402b38SGautham R Shenoy spin_unlock(&workqueue_lock); 33463af24433SOleg Nesterov 3347e22bee78STejun Heo /* sanity check */ 3348f3421797STejun Heo for_each_cwq_cpu(cpu, wq) { 334973f53c4aSTejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 335073f53c4aSTejun Heo int i; 33513af24433SOleg Nesterov 335273f53c4aSTejun Heo for (i = 0; i < WORK_NR_COLORS; i++) 335373f53c4aSTejun Heo BUG_ON(cwq->nr_in_flight[i]); 33541e19ffc6STejun Heo BUG_ON(cwq->nr_active); 33551e19ffc6STejun Heo BUG_ON(!list_empty(&cwq->delayed_works)); 335673f53c4aSTejun Heo } 33571537663fSTejun Heo 3358e22bee78STejun Heo if (wq->flags & WQ_RESCUER) { 3359e22bee78STejun Heo kthread_stop(wq->rescuer->task); 3360f2e005aaSTejun Heo free_mayday_mask(wq->mayday_mask); 33618d9df9f0SXiaotian Feng kfree(wq->rescuer); 3362e22bee78STejun Heo } 3363e22bee78STejun Heo 3364bdbc5dd7STejun Heo free_cwqs(wq); 33653af24433SOleg Nesterov kfree(wq); 33663af24433SOleg Nesterov } 33673af24433SOleg Nesterov EXPORT_SYMBOL_GPL(destroy_workqueue); 33683af24433SOleg Nesterov 3369dcd989cbSTejun Heo /** 33709f4bd4cdSLai Jiangshan * cwq_set_max_active - adjust max_active of a cwq 33719f4bd4cdSLai Jiangshan * @cwq: target cpu_workqueue_struct 33729f4bd4cdSLai Jiangshan * @max_active: new max_active value. 33739f4bd4cdSLai Jiangshan * 33749f4bd4cdSLai Jiangshan * Set @cwq->max_active to @max_active and activate delayed works if 33759f4bd4cdSLai Jiangshan * increased. 33769f4bd4cdSLai Jiangshan * 33779f4bd4cdSLai Jiangshan * CONTEXT: 33789f4bd4cdSLai Jiangshan * spin_lock_irq(gcwq->lock). 33799f4bd4cdSLai Jiangshan */ 33809f4bd4cdSLai Jiangshan static void cwq_set_max_active(struct cpu_workqueue_struct *cwq, int max_active) 33819f4bd4cdSLai Jiangshan { 33829f4bd4cdSLai Jiangshan cwq->max_active = max_active; 33839f4bd4cdSLai Jiangshan 33849f4bd4cdSLai Jiangshan while (!list_empty(&cwq->delayed_works) && 33859f4bd4cdSLai Jiangshan cwq->nr_active < cwq->max_active) 33869f4bd4cdSLai Jiangshan cwq_activate_first_delayed(cwq); 33879f4bd4cdSLai Jiangshan } 33889f4bd4cdSLai Jiangshan 33899f4bd4cdSLai Jiangshan /** 3390dcd989cbSTejun Heo * workqueue_set_max_active - adjust max_active of a workqueue 3391dcd989cbSTejun Heo * @wq: target workqueue 3392dcd989cbSTejun Heo * @max_active: new max_active value. 3393dcd989cbSTejun Heo * 3394dcd989cbSTejun Heo * Set max_active of @wq to @max_active. 3395dcd989cbSTejun Heo * 3396dcd989cbSTejun Heo * CONTEXT: 3397dcd989cbSTejun Heo * Don't call from IRQ context. 3398dcd989cbSTejun Heo */ 3399dcd989cbSTejun Heo void workqueue_set_max_active(struct workqueue_struct *wq, int max_active) 3400dcd989cbSTejun Heo { 3401dcd989cbSTejun Heo unsigned int cpu; 3402dcd989cbSTejun Heo 3403f3421797STejun Heo max_active = wq_clamp_max_active(max_active, wq->flags, wq->name); 3404dcd989cbSTejun Heo 3405dcd989cbSTejun Heo spin_lock(&workqueue_lock); 3406dcd989cbSTejun Heo 3407dcd989cbSTejun Heo wq->saved_max_active = max_active; 3408dcd989cbSTejun Heo 3409f3421797STejun Heo for_each_cwq_cpu(cpu, wq) { 3410dcd989cbSTejun Heo struct global_cwq *gcwq = get_gcwq(cpu); 3411dcd989cbSTejun Heo 3412dcd989cbSTejun Heo spin_lock_irq(&gcwq->lock); 3413dcd989cbSTejun Heo 341458a69cb4STejun Heo if (!(wq->flags & WQ_FREEZABLE) || 3415dcd989cbSTejun Heo !(gcwq->flags & GCWQ_FREEZING)) 341670369b11SLai Jiangshan cwq_set_max_active(get_cwq(gcwq->cpu, wq), max_active); 3417dcd989cbSTejun Heo 3418dcd989cbSTejun Heo spin_unlock_irq(&gcwq->lock); 3419dcd989cbSTejun Heo } 3420dcd989cbSTejun Heo 3421dcd989cbSTejun Heo spin_unlock(&workqueue_lock); 3422dcd989cbSTejun Heo } 3423dcd989cbSTejun Heo EXPORT_SYMBOL_GPL(workqueue_set_max_active); 3424dcd989cbSTejun Heo 3425dcd989cbSTejun Heo /** 3426dcd989cbSTejun Heo * workqueue_congested - test whether a workqueue is congested 3427dcd989cbSTejun Heo * @cpu: CPU in question 3428dcd989cbSTejun Heo * @wq: target workqueue 3429dcd989cbSTejun Heo * 3430dcd989cbSTejun Heo * Test whether @wq's cpu workqueue for @cpu is congested. There is 3431dcd989cbSTejun Heo * no synchronization around this function and the test result is 3432dcd989cbSTejun Heo * unreliable and only useful as advisory hints or for debugging. 3433dcd989cbSTejun Heo * 3434dcd989cbSTejun Heo * RETURNS: 3435dcd989cbSTejun Heo * %true if congested, %false otherwise. 3436dcd989cbSTejun Heo */ 3437dcd989cbSTejun Heo bool workqueue_congested(unsigned int cpu, struct workqueue_struct *wq) 3438dcd989cbSTejun Heo { 3439dcd989cbSTejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 3440dcd989cbSTejun Heo 3441dcd989cbSTejun Heo return !list_empty(&cwq->delayed_works); 3442dcd989cbSTejun Heo } 3443dcd989cbSTejun Heo EXPORT_SYMBOL_GPL(workqueue_congested); 3444dcd989cbSTejun Heo 3445dcd989cbSTejun Heo /** 3446dcd989cbSTejun Heo * work_cpu - return the last known associated cpu for @work 3447dcd989cbSTejun Heo * @work: the work of interest 3448dcd989cbSTejun Heo * 3449dcd989cbSTejun Heo * RETURNS: 3450bdbc5dd7STejun Heo * CPU number if @work was ever queued. WORK_CPU_NONE otherwise. 3451dcd989cbSTejun Heo */ 3452dcd989cbSTejun Heo unsigned int work_cpu(struct work_struct *work) 3453dcd989cbSTejun Heo { 3454dcd989cbSTejun Heo struct global_cwq *gcwq = get_work_gcwq(work); 3455dcd989cbSTejun Heo 3456bdbc5dd7STejun Heo return gcwq ? gcwq->cpu : WORK_CPU_NONE; 3457dcd989cbSTejun Heo } 3458dcd989cbSTejun Heo EXPORT_SYMBOL_GPL(work_cpu); 3459dcd989cbSTejun Heo 3460dcd989cbSTejun Heo /** 3461dcd989cbSTejun Heo * work_busy - test whether a work is currently pending or running 3462dcd989cbSTejun Heo * @work: the work to be tested 3463dcd989cbSTejun Heo * 3464dcd989cbSTejun Heo * Test whether @work is currently pending or running. There is no 3465dcd989cbSTejun Heo * synchronization around this function and the test result is 3466dcd989cbSTejun Heo * unreliable and only useful as advisory hints or for debugging. 3467dcd989cbSTejun Heo * Especially for reentrant wqs, the pending state might hide the 3468dcd989cbSTejun Heo * running state. 3469dcd989cbSTejun Heo * 3470dcd989cbSTejun Heo * RETURNS: 3471dcd989cbSTejun Heo * OR'd bitmask of WORK_BUSY_* bits. 3472dcd989cbSTejun Heo */ 3473dcd989cbSTejun Heo unsigned int work_busy(struct work_struct *work) 3474dcd989cbSTejun Heo { 3475dcd989cbSTejun Heo struct global_cwq *gcwq = get_work_gcwq(work); 3476dcd989cbSTejun Heo unsigned long flags; 3477dcd989cbSTejun Heo unsigned int ret = 0; 3478dcd989cbSTejun Heo 3479dcd989cbSTejun Heo if (!gcwq) 3480999767beSJoonsoo Kim return 0; 3481dcd989cbSTejun Heo 3482dcd989cbSTejun Heo spin_lock_irqsave(&gcwq->lock, flags); 3483dcd989cbSTejun Heo 3484dcd989cbSTejun Heo if (work_pending(work)) 3485dcd989cbSTejun Heo ret |= WORK_BUSY_PENDING; 3486dcd989cbSTejun Heo if (find_worker_executing_work(gcwq, work)) 3487dcd989cbSTejun Heo ret |= WORK_BUSY_RUNNING; 3488dcd989cbSTejun Heo 3489dcd989cbSTejun Heo spin_unlock_irqrestore(&gcwq->lock, flags); 3490dcd989cbSTejun Heo 3491dcd989cbSTejun Heo return ret; 3492dcd989cbSTejun Heo } 3493dcd989cbSTejun Heo EXPORT_SYMBOL_GPL(work_busy); 3494dcd989cbSTejun Heo 3495db7bccf4STejun Heo /* 3496db7bccf4STejun Heo * CPU hotplug. 3497db7bccf4STejun Heo * 3498e22bee78STejun Heo * There are two challenges in supporting CPU hotplug. Firstly, there 3499e22bee78STejun Heo * are a lot of assumptions on strong associations among work, cwq and 3500e22bee78STejun Heo * gcwq which make migrating pending and scheduled works very 3501e22bee78STejun Heo * difficult to implement without impacting hot paths. Secondly, 3502e22bee78STejun Heo * gcwqs serve mix of short, long and very long running works making 3503e22bee78STejun Heo * blocked draining impractical. 3504e22bee78STejun Heo * 3505628c78e7STejun Heo * This is solved by allowing a gcwq to be disassociated from the CPU 3506628c78e7STejun Heo * running as an unbound one and allowing it to be reattached later if the 3507628c78e7STejun Heo * cpu comes back online. 3508db7bccf4STejun Heo */ 3509db7bccf4STejun Heo 351060373152STejun Heo /* claim manager positions of all pools */ 3511b2eb83d1SLai Jiangshan static void gcwq_claim_assoc_and_lock(struct global_cwq *gcwq) 351260373152STejun Heo { 351360373152STejun Heo struct worker_pool *pool; 351460373152STejun Heo 351560373152STejun Heo for_each_worker_pool(pool, gcwq) 3516b2eb83d1SLai Jiangshan mutex_lock_nested(&pool->assoc_mutex, pool - gcwq->pools); 35178db25e78STejun Heo spin_lock_irq(&gcwq->lock); 351860373152STejun Heo } 351960373152STejun Heo 352060373152STejun Heo /* release manager positions */ 3521b2eb83d1SLai Jiangshan static void gcwq_release_assoc_and_unlock(struct global_cwq *gcwq) 352260373152STejun Heo { 352360373152STejun Heo struct worker_pool *pool; 352460373152STejun Heo 35258db25e78STejun Heo spin_unlock_irq(&gcwq->lock); 352660373152STejun Heo for_each_worker_pool(pool, gcwq) 3527b2eb83d1SLai Jiangshan mutex_unlock(&pool->assoc_mutex); 352860373152STejun Heo } 352960373152STejun Heo 3530628c78e7STejun Heo static void gcwq_unbind_fn(struct work_struct *work) 3531db7bccf4STejun Heo { 3532628c78e7STejun Heo struct global_cwq *gcwq = get_gcwq(smp_processor_id()); 35334ce62e9eSTejun Heo struct worker_pool *pool; 3534db7bccf4STejun Heo struct worker *worker; 3535db7bccf4STejun Heo struct hlist_node *pos; 3536db7bccf4STejun Heo int i; 3537db7bccf4STejun Heo 3538db7bccf4STejun Heo BUG_ON(gcwq->cpu != smp_processor_id()); 3539db7bccf4STejun Heo 3540b2eb83d1SLai Jiangshan gcwq_claim_assoc_and_lock(gcwq); 3541e22bee78STejun Heo 3542f2d5a0eeSTejun Heo /* 3543f2d5a0eeSTejun Heo * We've claimed all manager positions. Make all workers unbound 3544f2d5a0eeSTejun Heo * and set DISASSOCIATED. Before this, all workers except for the 3545f2d5a0eeSTejun Heo * ones which are still executing works from before the last CPU 3546f2d5a0eeSTejun Heo * down must be on the cpu. After this, they may become diasporas. 3547f2d5a0eeSTejun Heo */ 354860373152STejun Heo for_each_worker_pool(pool, gcwq) 35494ce62e9eSTejun Heo list_for_each_entry(worker, &pool->idle_list, entry) 3550403c821dSTejun Heo worker->flags |= WORKER_UNBOUND; 3551db7bccf4STejun Heo 3552db7bccf4STejun Heo for_each_busy_worker(worker, i, pos, gcwq) 3553403c821dSTejun Heo worker->flags |= WORKER_UNBOUND; 3554db7bccf4STejun Heo 3555f2d5a0eeSTejun Heo gcwq->flags |= GCWQ_DISASSOCIATED; 3556f2d5a0eeSTejun Heo 3557b2eb83d1SLai Jiangshan gcwq_release_assoc_and_unlock(gcwq); 3558e22bee78STejun Heo 3559e22bee78STejun Heo /* 3560628c78e7STejun Heo * Call schedule() so that we cross rq->lock and thus can guarantee 3561628c78e7STejun Heo * sched callbacks see the %WORKER_UNBOUND flag. This is necessary 3562628c78e7STejun Heo * as scheduler callbacks may be invoked from other cpus. 3563628c78e7STejun Heo */ 3564628c78e7STejun Heo schedule(); 3565628c78e7STejun Heo 3566628c78e7STejun Heo /* 3567628c78e7STejun Heo * Sched callbacks are disabled now. Zap nr_running. After this, 3568628c78e7STejun Heo * nr_running stays zero and need_more_worker() and keep_working() 3569628c78e7STejun Heo * are always true as long as the worklist is not empty. @gcwq now 3570628c78e7STejun Heo * behaves as unbound (in terms of concurrency management) gcwq 3571628c78e7STejun Heo * which is served by workers tied to the CPU. 3572628c78e7STejun Heo * 3573628c78e7STejun Heo * On return from this function, the current worker would trigger 3574628c78e7STejun Heo * unbound chain execution of pending work items if other workers 3575628c78e7STejun Heo * didn't already. 3576e22bee78STejun Heo */ 35774ce62e9eSTejun Heo for_each_worker_pool(pool, gcwq) 35784ce62e9eSTejun Heo atomic_set(get_pool_nr_running(pool), 0); 3579db7bccf4STejun Heo } 3580db7bccf4STejun Heo 35818db25e78STejun Heo /* 35828db25e78STejun Heo * Workqueues should be brought up before normal priority CPU notifiers. 35838db25e78STejun Heo * This will be registered high priority CPU notifier. 35848db25e78STejun Heo */ 35859fdf9b73SLai Jiangshan static int __cpuinit workqueue_cpu_up_callback(struct notifier_block *nfb, 35861da177e4SLinus Torvalds unsigned long action, 35871da177e4SLinus Torvalds void *hcpu) 35881da177e4SLinus Torvalds { 35893af24433SOleg Nesterov unsigned int cpu = (unsigned long)hcpu; 3590db7bccf4STejun Heo struct global_cwq *gcwq = get_gcwq(cpu); 35914ce62e9eSTejun Heo struct worker_pool *pool; 35921da177e4SLinus Torvalds 35938db25e78STejun Heo switch (action & ~CPU_TASKS_FROZEN) { 35943af24433SOleg Nesterov case CPU_UP_PREPARE: 35954ce62e9eSTejun Heo for_each_worker_pool(pool, gcwq) { 35963ce63377STejun Heo struct worker *worker; 35973ce63377STejun Heo 35983ce63377STejun Heo if (pool->nr_workers) 35993ce63377STejun Heo continue; 36003ce63377STejun Heo 36013ce63377STejun Heo worker = create_worker(pool); 36023ce63377STejun Heo if (!worker) 36033ce63377STejun Heo return NOTIFY_BAD; 36043ce63377STejun Heo 36053ce63377STejun Heo spin_lock_irq(&gcwq->lock); 36063ce63377STejun Heo start_worker(worker); 36073ce63377STejun Heo spin_unlock_irq(&gcwq->lock); 36083af24433SOleg Nesterov } 36091da177e4SLinus Torvalds break; 36101da177e4SLinus Torvalds 361165758202STejun Heo case CPU_DOWN_FAILED: 361265758202STejun Heo case CPU_ONLINE: 3613b2eb83d1SLai Jiangshan gcwq_claim_assoc_and_lock(gcwq); 36148db25e78STejun Heo gcwq->flags &= ~GCWQ_DISASSOCIATED; 36158db25e78STejun Heo rebind_workers(gcwq); 3616b2eb83d1SLai Jiangshan gcwq_release_assoc_and_unlock(gcwq); 36178db25e78STejun Heo break; 361865758202STejun Heo } 361965758202STejun Heo return NOTIFY_OK; 362065758202STejun Heo } 362165758202STejun Heo 362265758202STejun Heo /* 362365758202STejun Heo * Workqueues should be brought down after normal priority CPU notifiers. 362465758202STejun Heo * This will be registered as low priority CPU notifier. 362565758202STejun Heo */ 36269fdf9b73SLai Jiangshan static int __cpuinit workqueue_cpu_down_callback(struct notifier_block *nfb, 362765758202STejun Heo unsigned long action, 362865758202STejun Heo void *hcpu) 362965758202STejun Heo { 36308db25e78STejun Heo unsigned int cpu = (unsigned long)hcpu; 36318db25e78STejun Heo struct work_struct unbind_work; 36328db25e78STejun Heo 363365758202STejun Heo switch (action & ~CPU_TASKS_FROZEN) { 363465758202STejun Heo case CPU_DOWN_PREPARE: 36358db25e78STejun Heo /* unbinding should happen on the local CPU */ 36368db25e78STejun Heo INIT_WORK_ONSTACK(&unbind_work, gcwq_unbind_fn); 36377635d2fdSJoonsoo Kim queue_work_on(cpu, system_highpri_wq, &unbind_work); 36388db25e78STejun Heo flush_work(&unbind_work); 36398db25e78STejun Heo break; 364065758202STejun Heo } 364165758202STejun Heo return NOTIFY_OK; 364265758202STejun Heo } 364365758202STejun Heo 36442d3854a3SRusty Russell #ifdef CONFIG_SMP 36458ccad40dSRusty Russell 36462d3854a3SRusty Russell struct work_for_cpu { 3647ed48ece2STejun Heo struct work_struct work; 36482d3854a3SRusty Russell long (*fn)(void *); 36492d3854a3SRusty Russell void *arg; 36502d3854a3SRusty Russell long ret; 36512d3854a3SRusty Russell }; 36522d3854a3SRusty Russell 3653ed48ece2STejun Heo static void work_for_cpu_fn(struct work_struct *work) 36542d3854a3SRusty Russell { 3655ed48ece2STejun Heo struct work_for_cpu *wfc = container_of(work, struct work_for_cpu, work); 3656ed48ece2STejun Heo 36572d3854a3SRusty Russell wfc->ret = wfc->fn(wfc->arg); 36582d3854a3SRusty Russell } 36592d3854a3SRusty Russell 36602d3854a3SRusty Russell /** 36612d3854a3SRusty Russell * work_on_cpu - run a function in user context on a particular cpu 36622d3854a3SRusty Russell * @cpu: the cpu to run on 36632d3854a3SRusty Russell * @fn: the function to run 36642d3854a3SRusty Russell * @arg: the function arg 36652d3854a3SRusty Russell * 366631ad9081SRusty Russell * This will return the value @fn returns. 366731ad9081SRusty Russell * It is up to the caller to ensure that the cpu doesn't go offline. 36686b44003eSAndrew Morton * The caller must not hold any locks which would prevent @fn from completing. 36692d3854a3SRusty Russell */ 36702d3854a3SRusty Russell long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg) 36712d3854a3SRusty Russell { 3672ed48ece2STejun Heo struct work_for_cpu wfc = { .fn = fn, .arg = arg }; 36732d3854a3SRusty Russell 3674ed48ece2STejun Heo INIT_WORK_ONSTACK(&wfc.work, work_for_cpu_fn); 3675ed48ece2STejun Heo schedule_work_on(cpu, &wfc.work); 3676ed48ece2STejun Heo flush_work(&wfc.work); 36772d3854a3SRusty Russell return wfc.ret; 36782d3854a3SRusty Russell } 36792d3854a3SRusty Russell EXPORT_SYMBOL_GPL(work_on_cpu); 36802d3854a3SRusty Russell #endif /* CONFIG_SMP */ 36812d3854a3SRusty Russell 3682a0a1a5fdSTejun Heo #ifdef CONFIG_FREEZER 3683e7577c50SRusty Russell 3684a0a1a5fdSTejun Heo /** 3685a0a1a5fdSTejun Heo * freeze_workqueues_begin - begin freezing workqueues 3686a0a1a5fdSTejun Heo * 368758a69cb4STejun Heo * Start freezing workqueues. After this function returns, all freezable 368858a69cb4STejun Heo * workqueues will queue new works to their frozen_works list instead of 368958a69cb4STejun Heo * gcwq->worklist. 3690a0a1a5fdSTejun Heo * 3691a0a1a5fdSTejun Heo * CONTEXT: 36928b03ae3cSTejun Heo * Grabs and releases workqueue_lock and gcwq->lock's. 3693a0a1a5fdSTejun Heo */ 3694a0a1a5fdSTejun Heo void freeze_workqueues_begin(void) 3695a0a1a5fdSTejun Heo { 3696a0a1a5fdSTejun Heo unsigned int cpu; 3697a0a1a5fdSTejun Heo 3698a0a1a5fdSTejun Heo spin_lock(&workqueue_lock); 3699a0a1a5fdSTejun Heo 3700a0a1a5fdSTejun Heo BUG_ON(workqueue_freezing); 3701a0a1a5fdSTejun Heo workqueue_freezing = true; 3702a0a1a5fdSTejun Heo 3703f3421797STejun Heo for_each_gcwq_cpu(cpu) { 37048b03ae3cSTejun Heo struct global_cwq *gcwq = get_gcwq(cpu); 3705bdbc5dd7STejun Heo struct workqueue_struct *wq; 37068b03ae3cSTejun Heo 37078b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 37088b03ae3cSTejun Heo 3709db7bccf4STejun Heo BUG_ON(gcwq->flags & GCWQ_FREEZING); 3710db7bccf4STejun Heo gcwq->flags |= GCWQ_FREEZING; 3711db7bccf4STejun Heo 3712a0a1a5fdSTejun Heo list_for_each_entry(wq, &workqueues, list) { 3713a0a1a5fdSTejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 3714a0a1a5fdSTejun Heo 371558a69cb4STejun Heo if (cwq && wq->flags & WQ_FREEZABLE) 3716a0a1a5fdSTejun Heo cwq->max_active = 0; 37171da177e4SLinus Torvalds } 37188b03ae3cSTejun Heo 37198b03ae3cSTejun Heo spin_unlock_irq(&gcwq->lock); 3720a0a1a5fdSTejun Heo } 3721a0a1a5fdSTejun Heo 3722a0a1a5fdSTejun Heo spin_unlock(&workqueue_lock); 3723a0a1a5fdSTejun Heo } 3724a0a1a5fdSTejun Heo 3725a0a1a5fdSTejun Heo /** 372658a69cb4STejun Heo * freeze_workqueues_busy - are freezable workqueues still busy? 3727a0a1a5fdSTejun Heo * 3728a0a1a5fdSTejun Heo * Check whether freezing is complete. This function must be called 3729a0a1a5fdSTejun Heo * between freeze_workqueues_begin() and thaw_workqueues(). 3730a0a1a5fdSTejun Heo * 3731a0a1a5fdSTejun Heo * CONTEXT: 3732a0a1a5fdSTejun Heo * Grabs and releases workqueue_lock. 3733a0a1a5fdSTejun Heo * 3734a0a1a5fdSTejun Heo * RETURNS: 373558a69cb4STejun Heo * %true if some freezable workqueues are still busy. %false if freezing 373658a69cb4STejun Heo * is complete. 3737a0a1a5fdSTejun Heo */ 3738a0a1a5fdSTejun Heo bool freeze_workqueues_busy(void) 3739a0a1a5fdSTejun Heo { 3740a0a1a5fdSTejun Heo unsigned int cpu; 3741a0a1a5fdSTejun Heo bool busy = false; 3742a0a1a5fdSTejun Heo 3743a0a1a5fdSTejun Heo spin_lock(&workqueue_lock); 3744a0a1a5fdSTejun Heo 3745a0a1a5fdSTejun Heo BUG_ON(!workqueue_freezing); 3746a0a1a5fdSTejun Heo 3747f3421797STejun Heo for_each_gcwq_cpu(cpu) { 3748bdbc5dd7STejun Heo struct workqueue_struct *wq; 3749a0a1a5fdSTejun Heo /* 3750a0a1a5fdSTejun Heo * nr_active is monotonically decreasing. It's safe 3751a0a1a5fdSTejun Heo * to peek without lock. 3752a0a1a5fdSTejun Heo */ 3753a0a1a5fdSTejun Heo list_for_each_entry(wq, &workqueues, list) { 3754a0a1a5fdSTejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 3755a0a1a5fdSTejun Heo 375658a69cb4STejun Heo if (!cwq || !(wq->flags & WQ_FREEZABLE)) 3757a0a1a5fdSTejun Heo continue; 3758a0a1a5fdSTejun Heo 3759a0a1a5fdSTejun Heo BUG_ON(cwq->nr_active < 0); 3760a0a1a5fdSTejun Heo if (cwq->nr_active) { 3761a0a1a5fdSTejun Heo busy = true; 3762a0a1a5fdSTejun Heo goto out_unlock; 3763a0a1a5fdSTejun Heo } 3764a0a1a5fdSTejun Heo } 3765a0a1a5fdSTejun Heo } 3766a0a1a5fdSTejun Heo out_unlock: 3767a0a1a5fdSTejun Heo spin_unlock(&workqueue_lock); 3768a0a1a5fdSTejun Heo return busy; 3769a0a1a5fdSTejun Heo } 3770a0a1a5fdSTejun Heo 3771a0a1a5fdSTejun Heo /** 3772a0a1a5fdSTejun Heo * thaw_workqueues - thaw workqueues 3773a0a1a5fdSTejun Heo * 3774a0a1a5fdSTejun Heo * Thaw workqueues. Normal queueing is restored and all collected 37757e11629dSTejun Heo * frozen works are transferred to their respective gcwq worklists. 3776a0a1a5fdSTejun Heo * 3777a0a1a5fdSTejun Heo * CONTEXT: 37788b03ae3cSTejun Heo * Grabs and releases workqueue_lock and gcwq->lock's. 3779a0a1a5fdSTejun Heo */ 3780a0a1a5fdSTejun Heo void thaw_workqueues(void) 3781a0a1a5fdSTejun Heo { 3782a0a1a5fdSTejun Heo unsigned int cpu; 3783a0a1a5fdSTejun Heo 3784a0a1a5fdSTejun Heo spin_lock(&workqueue_lock); 3785a0a1a5fdSTejun Heo 3786a0a1a5fdSTejun Heo if (!workqueue_freezing) 3787a0a1a5fdSTejun Heo goto out_unlock; 3788a0a1a5fdSTejun Heo 3789f3421797STejun Heo for_each_gcwq_cpu(cpu) { 37908b03ae3cSTejun Heo struct global_cwq *gcwq = get_gcwq(cpu); 37914ce62e9eSTejun Heo struct worker_pool *pool; 3792bdbc5dd7STejun Heo struct workqueue_struct *wq; 37938b03ae3cSTejun Heo 37948b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 37958b03ae3cSTejun Heo 3796db7bccf4STejun Heo BUG_ON(!(gcwq->flags & GCWQ_FREEZING)); 3797db7bccf4STejun Heo gcwq->flags &= ~GCWQ_FREEZING; 3798db7bccf4STejun Heo 3799a0a1a5fdSTejun Heo list_for_each_entry(wq, &workqueues, list) { 3800a0a1a5fdSTejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 3801a0a1a5fdSTejun Heo 380258a69cb4STejun Heo if (!cwq || !(wq->flags & WQ_FREEZABLE)) 3803a0a1a5fdSTejun Heo continue; 3804a0a1a5fdSTejun Heo 3805a0a1a5fdSTejun Heo /* restore max_active and repopulate worklist */ 38069f4bd4cdSLai Jiangshan cwq_set_max_active(cwq, wq->saved_max_active); 3807a0a1a5fdSTejun Heo } 38088b03ae3cSTejun Heo 38094ce62e9eSTejun Heo for_each_worker_pool(pool, gcwq) 38104ce62e9eSTejun Heo wake_up_worker(pool); 3811e22bee78STejun Heo 38128b03ae3cSTejun Heo spin_unlock_irq(&gcwq->lock); 3813a0a1a5fdSTejun Heo } 3814a0a1a5fdSTejun Heo 3815a0a1a5fdSTejun Heo workqueue_freezing = false; 3816a0a1a5fdSTejun Heo out_unlock: 3817a0a1a5fdSTejun Heo spin_unlock(&workqueue_lock); 3818a0a1a5fdSTejun Heo } 3819a0a1a5fdSTejun Heo #endif /* CONFIG_FREEZER */ 3820a0a1a5fdSTejun Heo 38216ee0578bSSuresh Siddha static int __init init_workqueues(void) 38221da177e4SLinus Torvalds { 3823c34056a3STejun Heo unsigned int cpu; 3824c34056a3STejun Heo 3825b5490077STejun Heo /* make sure we have enough bits for OFFQ CPU number */ 3826b5490077STejun Heo BUILD_BUG_ON((1LU << (BITS_PER_LONG - WORK_OFFQ_CPU_SHIFT)) < 3827b5490077STejun Heo WORK_CPU_LAST); 3828b5490077STejun Heo 382965758202STejun Heo cpu_notifier(workqueue_cpu_up_callback, CPU_PRI_WORKQUEUE_UP); 3830a5b4e57dSLai Jiangshan hotcpu_notifier(workqueue_cpu_down_callback, CPU_PRI_WORKQUEUE_DOWN); 38318b03ae3cSTejun Heo 38328b03ae3cSTejun Heo /* initialize gcwqs */ 3833f3421797STejun Heo for_each_gcwq_cpu(cpu) { 38348b03ae3cSTejun Heo struct global_cwq *gcwq = get_gcwq(cpu); 38354ce62e9eSTejun Heo struct worker_pool *pool; 38368b03ae3cSTejun Heo 38378b03ae3cSTejun Heo spin_lock_init(&gcwq->lock); 38388b03ae3cSTejun Heo gcwq->cpu = cpu; 3839f3421797STejun Heo gcwq->flags |= GCWQ_DISASSOCIATED; 38408b03ae3cSTejun Heo 384142f8570fSSasha Levin hash_init(gcwq->busy_hash); 3842c8e55f36STejun Heo 38434ce62e9eSTejun Heo for_each_worker_pool(pool, gcwq) { 38444ce62e9eSTejun Heo pool->gcwq = gcwq; 38454ce62e9eSTejun Heo INIT_LIST_HEAD(&pool->worklist); 38464ce62e9eSTejun Heo INIT_LIST_HEAD(&pool->idle_list); 3847e22bee78STejun Heo 38484ce62e9eSTejun Heo init_timer_deferrable(&pool->idle_timer); 38494ce62e9eSTejun Heo pool->idle_timer.function = idle_worker_timeout; 38504ce62e9eSTejun Heo pool->idle_timer.data = (unsigned long)pool; 3851e22bee78STejun Heo 38524ce62e9eSTejun Heo setup_timer(&pool->mayday_timer, gcwq_mayday_timeout, 38534ce62e9eSTejun Heo (unsigned long)pool); 38544ce62e9eSTejun Heo 3855b2eb83d1SLai Jiangshan mutex_init(&pool->assoc_mutex); 38564ce62e9eSTejun Heo ida_init(&pool->worker_ida); 38574ce62e9eSTejun Heo } 38588b03ae3cSTejun Heo } 38598b03ae3cSTejun Heo 3860e22bee78STejun Heo /* create the initial worker */ 3861f3421797STejun Heo for_each_online_gcwq_cpu(cpu) { 3862e22bee78STejun Heo struct global_cwq *gcwq = get_gcwq(cpu); 38634ce62e9eSTejun Heo struct worker_pool *pool; 3864e22bee78STejun Heo 3865477a3c33STejun Heo if (cpu != WORK_CPU_UNBOUND) 3866477a3c33STejun Heo gcwq->flags &= ~GCWQ_DISASSOCIATED; 38674ce62e9eSTejun Heo 38684ce62e9eSTejun Heo for_each_worker_pool(pool, gcwq) { 38694ce62e9eSTejun Heo struct worker *worker; 38704ce62e9eSTejun Heo 3871bc2ae0f5STejun Heo worker = create_worker(pool); 3872e22bee78STejun Heo BUG_ON(!worker); 3873e22bee78STejun Heo spin_lock_irq(&gcwq->lock); 3874e22bee78STejun Heo start_worker(worker); 3875e22bee78STejun Heo spin_unlock_irq(&gcwq->lock); 3876e22bee78STejun Heo } 38774ce62e9eSTejun Heo } 3878e22bee78STejun Heo 3879d320c038STejun Heo system_wq = alloc_workqueue("events", 0, 0); 38801aabe902SJoonsoo Kim system_highpri_wq = alloc_workqueue("events_highpri", WQ_HIGHPRI, 0); 3881d320c038STejun Heo system_long_wq = alloc_workqueue("events_long", 0, 0); 3882f3421797STejun Heo system_unbound_wq = alloc_workqueue("events_unbound", WQ_UNBOUND, 3883f3421797STejun Heo WQ_UNBOUND_MAX_ACTIVE); 388424d51addSTejun Heo system_freezable_wq = alloc_workqueue("events_freezable", 388524d51addSTejun Heo WQ_FREEZABLE, 0); 38861aabe902SJoonsoo Kim BUG_ON(!system_wq || !system_highpri_wq || !system_long_wq || 3887ae930e0fSTejun Heo !system_unbound_wq || !system_freezable_wq); 38886ee0578bSSuresh Siddha return 0; 38891da177e4SLinus Torvalds } 38906ee0578bSSuresh Siddha early_initcall(init_workqueues); 3891