11da177e4SLinus Torvalds /* 2c54fce6eSTejun Heo * kernel/workqueue.c - generic async execution with shared worker pool 31da177e4SLinus Torvalds * 4c54fce6eSTejun Heo * Copyright (C) 2002 Ingo Molnar 51da177e4SLinus Torvalds * 61da177e4SLinus Torvalds * Derived from the taskqueue/keventd code by: 71da177e4SLinus Torvalds * David Woodhouse <dwmw2@infradead.org> 8e1f8e874SFrancois Cami * Andrew Morton 91da177e4SLinus Torvalds * Kai Petzke <wpp@marie.physik.tu-berlin.de> 101da177e4SLinus Torvalds * Theodore Ts'o <tytso@mit.edu> 1189ada679SChristoph Lameter * 12cde53535SChristoph Lameter * Made to use alloc_percpu by Christoph Lameter. 13c54fce6eSTejun Heo * 14c54fce6eSTejun Heo * Copyright (C) 2010 SUSE Linux Products GmbH 15c54fce6eSTejun Heo * Copyright (C) 2010 Tejun Heo <tj@kernel.org> 16c54fce6eSTejun Heo * 17c54fce6eSTejun Heo * This is the generic async execution mechanism. Work items as are 18c54fce6eSTejun Heo * executed in process context. The worker pool is shared and 19c54fce6eSTejun Heo * automatically managed. There is one worker pool for each CPU and 20c54fce6eSTejun Heo * one extra for works which are better served by workers which are 21c54fce6eSTejun Heo * not bound to any specific CPU. 22c54fce6eSTejun Heo * 23c54fce6eSTejun Heo * Please read Documentation/workqueue.txt for details. 241da177e4SLinus Torvalds */ 251da177e4SLinus Torvalds 269984de1aSPaul Gortmaker #include <linux/export.h> 271da177e4SLinus Torvalds #include <linux/kernel.h> 281da177e4SLinus Torvalds #include <linux/sched.h> 291da177e4SLinus Torvalds #include <linux/init.h> 301da177e4SLinus Torvalds #include <linux/signal.h> 311da177e4SLinus Torvalds #include <linux/completion.h> 321da177e4SLinus Torvalds #include <linux/workqueue.h> 331da177e4SLinus Torvalds #include <linux/slab.h> 341da177e4SLinus Torvalds #include <linux/cpu.h> 351da177e4SLinus Torvalds #include <linux/notifier.h> 361da177e4SLinus Torvalds #include <linux/kthread.h> 371fa44ecaSJames Bottomley #include <linux/hardirq.h> 3846934023SChristoph Lameter #include <linux/mempolicy.h> 39341a5958SRafael J. Wysocki #include <linux/freezer.h> 40d5abe669SPeter Zijlstra #include <linux/kallsyms.h> 41d5abe669SPeter Zijlstra #include <linux/debug_locks.h> 424e6045f1SJohannes Berg #include <linux/lockdep.h> 43c34056a3STejun Heo #include <linux/idr.h> 44e22bee78STejun Heo 45e22bee78STejun Heo #include "workqueue_sched.h" 461da177e4SLinus Torvalds 47c8e55f36STejun Heo enum { 48bc2ae0f5STejun Heo /* 49bc2ae0f5STejun Heo * global_cwq flags 50bc2ae0f5STejun Heo * 51bc2ae0f5STejun Heo * A bound gcwq is either associated or disassociated with its CPU. 52bc2ae0f5STejun Heo * While associated (!DISASSOCIATED), all workers are bound to the 53bc2ae0f5STejun Heo * CPU and none has %WORKER_UNBOUND set and concurrency management 54bc2ae0f5STejun Heo * is in effect. 55bc2ae0f5STejun Heo * 56bc2ae0f5STejun Heo * While DISASSOCIATED, the cpu may be offline and all workers have 57bc2ae0f5STejun Heo * %WORKER_UNBOUND set and concurrency management disabled, and may 58bc2ae0f5STejun Heo * be executing on any CPU. The gcwq behaves as an unbound one. 59bc2ae0f5STejun Heo * 60bc2ae0f5STejun Heo * Note that DISASSOCIATED can be flipped only while holding 61bc2ae0f5STejun Heo * managership of all pools on the gcwq to avoid changing binding 62bc2ae0f5STejun Heo * state while create_worker() is in progress. 63bc2ae0f5STejun Heo */ 6411ebea50STejun Heo GCWQ_DISASSOCIATED = 1 << 0, /* cpu can't serve workers */ 6511ebea50STejun Heo GCWQ_FREEZING = 1 << 1, /* freeze in progress */ 6611ebea50STejun Heo 6711ebea50STejun Heo /* pool flags */ 6811ebea50STejun Heo POOL_MANAGE_WORKERS = 1 << 0, /* need to manage workers */ 69db7bccf4STejun Heo 70c8e55f36STejun Heo /* worker flags */ 71c8e55f36STejun Heo WORKER_STARTED = 1 << 0, /* started */ 72c8e55f36STejun Heo WORKER_DIE = 1 << 1, /* die die die */ 73c8e55f36STejun Heo WORKER_IDLE = 1 << 2, /* is idle */ 74e22bee78STejun Heo WORKER_PREP = 1 << 3, /* preparing to run works */ 75e22bee78STejun Heo WORKER_REBIND = 1 << 5, /* mom is home, come back */ 76fb0e7bebSTejun Heo WORKER_CPU_INTENSIVE = 1 << 6, /* cpu intensive */ 77f3421797STejun Heo WORKER_UNBOUND = 1 << 7, /* worker is unbound */ 78e22bee78STejun Heo 79403c821dSTejun Heo WORKER_NOT_RUNNING = WORKER_PREP | WORKER_REBIND | WORKER_UNBOUND | 80403c821dSTejun Heo WORKER_CPU_INTENSIVE, 81db7bccf4STejun Heo 823270476aSTejun Heo NR_WORKER_POOLS = 2, /* # worker pools per gcwq */ 834ce62e9eSTejun Heo 84c8e55f36STejun Heo BUSY_WORKER_HASH_ORDER = 6, /* 64 pointers */ 85c8e55f36STejun Heo BUSY_WORKER_HASH_SIZE = 1 << BUSY_WORKER_HASH_ORDER, 86c8e55f36STejun Heo BUSY_WORKER_HASH_MASK = BUSY_WORKER_HASH_SIZE - 1, 87db7bccf4STejun Heo 88e22bee78STejun Heo MAX_IDLE_WORKERS_RATIO = 4, /* 1/4 of busy can be idle */ 89e22bee78STejun Heo IDLE_WORKER_TIMEOUT = 300 * HZ, /* keep idle ones for 5 mins */ 90e22bee78STejun Heo 913233cdbdSTejun Heo MAYDAY_INITIAL_TIMEOUT = HZ / 100 >= 2 ? HZ / 100 : 2, 923233cdbdSTejun Heo /* call for help after 10ms 933233cdbdSTejun Heo (min two ticks) */ 94e22bee78STejun Heo MAYDAY_INTERVAL = HZ / 10, /* and then every 100ms */ 95e22bee78STejun Heo CREATE_COOLDOWN = HZ, /* time to breath after fail */ 961da177e4SLinus Torvalds 971da177e4SLinus Torvalds /* 98e22bee78STejun Heo * Rescue workers are used only on emergencies and shared by 99e22bee78STejun Heo * all cpus. Give -20. 100e22bee78STejun Heo */ 101e22bee78STejun Heo RESCUER_NICE_LEVEL = -20, 1023270476aSTejun Heo HIGHPRI_NICE_LEVEL = -20, 103c8e55f36STejun Heo }; 104c8e55f36STejun Heo 1051da177e4SLinus Torvalds /* 1064690c4abSTejun Heo * Structure fields follow one of the following exclusion rules. 1074690c4abSTejun Heo * 108e41e704bSTejun Heo * I: Modifiable by initialization/destruction paths and read-only for 109e41e704bSTejun Heo * everyone else. 1104690c4abSTejun Heo * 111e22bee78STejun Heo * P: Preemption protected. Disabling preemption is enough and should 112e22bee78STejun Heo * only be modified and accessed from the local cpu. 113e22bee78STejun Heo * 1148b03ae3cSTejun Heo * L: gcwq->lock protected. Access with gcwq->lock held. 1154690c4abSTejun Heo * 116e22bee78STejun Heo * X: During normal operation, modification requires gcwq->lock and 117e22bee78STejun Heo * should be done only from local cpu. Either disabling preemption 118e22bee78STejun Heo * on local cpu or grabbing gcwq->lock is enough for read access. 119f3421797STejun Heo * If GCWQ_DISASSOCIATED is set, it's identical to L. 120e22bee78STejun Heo * 12173f53c4aSTejun Heo * F: wq->flush_mutex protected. 12273f53c4aSTejun Heo * 1234690c4abSTejun Heo * W: workqueue_lock protected. 1244690c4abSTejun Heo */ 1254690c4abSTejun Heo 1268b03ae3cSTejun Heo struct global_cwq; 127bd7bdd43STejun Heo struct worker_pool; 12825511a47STejun Heo struct idle_rebind; 129c34056a3STejun Heo 130e22bee78STejun Heo /* 131e22bee78STejun Heo * The poor guys doing the actual heavy lifting. All on-duty workers 132e22bee78STejun Heo * are either serving the manager role, on idle list or on busy hash. 133e22bee78STejun Heo */ 134c34056a3STejun Heo struct worker { 135c8e55f36STejun Heo /* on idle list while idle, on busy hash table while busy */ 136c8e55f36STejun Heo union { 137c8e55f36STejun Heo struct list_head entry; /* L: while idle */ 138c8e55f36STejun Heo struct hlist_node hentry; /* L: while busy */ 139c8e55f36STejun Heo }; 140c8e55f36STejun Heo 141c34056a3STejun Heo struct work_struct *current_work; /* L: work being processed */ 1428cca0eeaSTejun Heo struct cpu_workqueue_struct *current_cwq; /* L: current_work's cwq */ 143affee4b2STejun Heo struct list_head scheduled; /* L: scheduled works */ 144c34056a3STejun Heo struct task_struct *task; /* I: worker task */ 145bd7bdd43STejun Heo struct worker_pool *pool; /* I: the associated pool */ 146e22bee78STejun Heo /* 64 bytes boundary on 64bit, 32 on 32bit */ 147e22bee78STejun Heo unsigned long last_active; /* L: last active timestamp */ 148e22bee78STejun Heo unsigned int flags; /* X: flags */ 149c34056a3STejun Heo int id; /* I: worker id */ 15025511a47STejun Heo 15125511a47STejun Heo /* for rebinding worker to CPU */ 15225511a47STejun Heo struct idle_rebind *idle_rebind; /* L: for idle worker */ 15325511a47STejun Heo struct work_struct rebind_work; /* L: for busy worker */ 154c34056a3STejun Heo }; 155c34056a3STejun Heo 156bd7bdd43STejun Heo struct worker_pool { 157bd7bdd43STejun Heo struct global_cwq *gcwq; /* I: the owning gcwq */ 15811ebea50STejun Heo unsigned int flags; /* X: flags */ 159bd7bdd43STejun Heo 160bd7bdd43STejun Heo struct list_head worklist; /* L: list of pending works */ 161bd7bdd43STejun Heo int nr_workers; /* L: total number of workers */ 162bd7bdd43STejun Heo int nr_idle; /* L: currently idle ones */ 163bd7bdd43STejun Heo 164bd7bdd43STejun Heo struct list_head idle_list; /* X: list of idle workers */ 165bd7bdd43STejun Heo struct timer_list idle_timer; /* L: worker idle timeout */ 166bd7bdd43STejun Heo struct timer_list mayday_timer; /* L: SOS timer for workers */ 167bd7bdd43STejun Heo 16860373152STejun Heo struct mutex manager_mutex; /* mutex manager should hold */ 169bd7bdd43STejun Heo struct ida worker_ida; /* L: for worker IDs */ 170bd7bdd43STejun Heo }; 171bd7bdd43STejun Heo 1724690c4abSTejun Heo /* 173e22bee78STejun Heo * Global per-cpu workqueue. There's one and only one for each cpu 174e22bee78STejun Heo * and all works are queued and processed here regardless of their 175e22bee78STejun Heo * target workqueues. 1768b03ae3cSTejun Heo */ 1778b03ae3cSTejun Heo struct global_cwq { 1788b03ae3cSTejun Heo spinlock_t lock; /* the gcwq lock */ 1798b03ae3cSTejun Heo unsigned int cpu; /* I: the associated cpu */ 180db7bccf4STejun Heo unsigned int flags; /* L: GCWQ_* flags */ 181c8e55f36STejun Heo 182bd7bdd43STejun Heo /* workers are chained either in busy_hash or pool idle_list */ 183c8e55f36STejun Heo struct hlist_head busy_hash[BUSY_WORKER_HASH_SIZE]; 184c8e55f36STejun Heo /* L: hash of busy workers */ 185c8e55f36STejun Heo 186330dad5bSJoonsoo Kim struct worker_pool pools[NR_WORKER_POOLS]; 187330dad5bSJoonsoo Kim /* normal and highpri pools */ 188db7bccf4STejun Heo 18925511a47STejun Heo wait_queue_head_t rebind_hold; /* rebind hold wait */ 1908b03ae3cSTejun Heo } ____cacheline_aligned_in_smp; 1918b03ae3cSTejun Heo 1928b03ae3cSTejun Heo /* 193502ca9d8STejun Heo * The per-CPU workqueue. The lower WORK_STRUCT_FLAG_BITS of 1940f900049STejun Heo * work_struct->data are used for flags and thus cwqs need to be 1950f900049STejun Heo * aligned at two's power of the number of flag bits. 1961da177e4SLinus Torvalds */ 1971da177e4SLinus Torvalds struct cpu_workqueue_struct { 198bd7bdd43STejun Heo struct worker_pool *pool; /* I: the associated pool */ 1994690c4abSTejun Heo struct workqueue_struct *wq; /* I: the owning workqueue */ 20073f53c4aSTejun Heo int work_color; /* L: current color */ 20173f53c4aSTejun Heo int flush_color; /* L: flushing color */ 20273f53c4aSTejun Heo int nr_in_flight[WORK_NR_COLORS]; 20373f53c4aSTejun Heo /* L: nr of in_flight works */ 2041e19ffc6STejun Heo int nr_active; /* L: nr of active works */ 205a0a1a5fdSTejun Heo int max_active; /* L: max active works */ 2061e19ffc6STejun Heo struct list_head delayed_works; /* L: delayed works */ 2070f900049STejun Heo }; 2081da177e4SLinus Torvalds 2091da177e4SLinus Torvalds /* 21073f53c4aSTejun Heo * Structure used to wait for workqueue flush. 21173f53c4aSTejun Heo */ 21273f53c4aSTejun Heo struct wq_flusher { 21373f53c4aSTejun Heo struct list_head list; /* F: list of flushers */ 21473f53c4aSTejun Heo int flush_color; /* F: flush color waiting for */ 21573f53c4aSTejun Heo struct completion done; /* flush completion */ 21673f53c4aSTejun Heo }; 2171da177e4SLinus Torvalds 21873f53c4aSTejun Heo /* 219f2e005aaSTejun Heo * All cpumasks are assumed to be always set on UP and thus can't be 220f2e005aaSTejun Heo * used to determine whether there's something to be done. 221f2e005aaSTejun Heo */ 222f2e005aaSTejun Heo #ifdef CONFIG_SMP 223f2e005aaSTejun Heo typedef cpumask_var_t mayday_mask_t; 224f2e005aaSTejun Heo #define mayday_test_and_set_cpu(cpu, mask) \ 225f2e005aaSTejun Heo cpumask_test_and_set_cpu((cpu), (mask)) 226f2e005aaSTejun Heo #define mayday_clear_cpu(cpu, mask) cpumask_clear_cpu((cpu), (mask)) 227f2e005aaSTejun Heo #define for_each_mayday_cpu(cpu, mask) for_each_cpu((cpu), (mask)) 2289c37547aSTejun Heo #define alloc_mayday_mask(maskp, gfp) zalloc_cpumask_var((maskp), (gfp)) 229f2e005aaSTejun Heo #define free_mayday_mask(mask) free_cpumask_var((mask)) 230f2e005aaSTejun Heo #else 231f2e005aaSTejun Heo typedef unsigned long mayday_mask_t; 232f2e005aaSTejun Heo #define mayday_test_and_set_cpu(cpu, mask) test_and_set_bit(0, &(mask)) 233f2e005aaSTejun Heo #define mayday_clear_cpu(cpu, mask) clear_bit(0, &(mask)) 234f2e005aaSTejun Heo #define for_each_mayday_cpu(cpu, mask) if ((cpu) = 0, (mask)) 235f2e005aaSTejun Heo #define alloc_mayday_mask(maskp, gfp) true 236f2e005aaSTejun Heo #define free_mayday_mask(mask) do { } while (0) 237f2e005aaSTejun Heo #endif 2381da177e4SLinus Torvalds 2391da177e4SLinus Torvalds /* 2401da177e4SLinus Torvalds * The externally visible workqueue abstraction is an array of 2411da177e4SLinus Torvalds * per-CPU workqueues: 2421da177e4SLinus Torvalds */ 2431da177e4SLinus Torvalds struct workqueue_struct { 2449c5a2ba7STejun Heo unsigned int flags; /* W: WQ_* flags */ 245bdbc5dd7STejun Heo union { 246bdbc5dd7STejun Heo struct cpu_workqueue_struct __percpu *pcpu; 247bdbc5dd7STejun Heo struct cpu_workqueue_struct *single; 248bdbc5dd7STejun Heo unsigned long v; 249bdbc5dd7STejun Heo } cpu_wq; /* I: cwq's */ 2504690c4abSTejun Heo struct list_head list; /* W: list of all workqueues */ 25173f53c4aSTejun Heo 25273f53c4aSTejun Heo struct mutex flush_mutex; /* protects wq flushing */ 25373f53c4aSTejun Heo int work_color; /* F: current work color */ 25473f53c4aSTejun Heo int flush_color; /* F: current flush color */ 25573f53c4aSTejun Heo atomic_t nr_cwqs_to_flush; /* flush in progress */ 25673f53c4aSTejun Heo struct wq_flusher *first_flusher; /* F: first flusher */ 25773f53c4aSTejun Heo struct list_head flusher_queue; /* F: flush waiters */ 25873f53c4aSTejun Heo struct list_head flusher_overflow; /* F: flush overflow list */ 25973f53c4aSTejun Heo 260f2e005aaSTejun Heo mayday_mask_t mayday_mask; /* cpus requesting rescue */ 261e22bee78STejun Heo struct worker *rescuer; /* I: rescue worker */ 262e22bee78STejun Heo 2639c5a2ba7STejun Heo int nr_drainers; /* W: drain in progress */ 264dcd989cbSTejun Heo int saved_max_active; /* W: saved cwq max_active */ 2654e6045f1SJohannes Berg #ifdef CONFIG_LOCKDEP 2664e6045f1SJohannes Berg struct lockdep_map lockdep_map; 2674e6045f1SJohannes Berg #endif 268b196be89STejun Heo char name[]; /* I: workqueue name */ 2691da177e4SLinus Torvalds }; 2701da177e4SLinus Torvalds 271d320c038STejun Heo struct workqueue_struct *system_wq __read_mostly; 272d320c038STejun Heo struct workqueue_struct *system_long_wq __read_mostly; 273d320c038STejun Heo struct workqueue_struct *system_nrt_wq __read_mostly; 274f3421797STejun Heo struct workqueue_struct *system_unbound_wq __read_mostly; 27524d51addSTejun Heo struct workqueue_struct *system_freezable_wq __read_mostly; 27662d3c543SAlan Stern struct workqueue_struct *system_nrt_freezable_wq __read_mostly; 277d320c038STejun Heo EXPORT_SYMBOL_GPL(system_wq); 278d320c038STejun Heo EXPORT_SYMBOL_GPL(system_long_wq); 279d320c038STejun Heo EXPORT_SYMBOL_GPL(system_nrt_wq); 280f3421797STejun Heo EXPORT_SYMBOL_GPL(system_unbound_wq); 28124d51addSTejun Heo EXPORT_SYMBOL_GPL(system_freezable_wq); 28262d3c543SAlan Stern EXPORT_SYMBOL_GPL(system_nrt_freezable_wq); 283d320c038STejun Heo 28497bd2347STejun Heo #define CREATE_TRACE_POINTS 28597bd2347STejun Heo #include <trace/events/workqueue.h> 28697bd2347STejun Heo 2874ce62e9eSTejun Heo #define for_each_worker_pool(pool, gcwq) \ 2883270476aSTejun Heo for ((pool) = &(gcwq)->pools[0]; \ 2893270476aSTejun Heo (pool) < &(gcwq)->pools[NR_WORKER_POOLS]; (pool)++) 2904ce62e9eSTejun Heo 291db7bccf4STejun Heo #define for_each_busy_worker(worker, i, pos, gcwq) \ 292db7bccf4STejun Heo for (i = 0; i < BUSY_WORKER_HASH_SIZE; i++) \ 293db7bccf4STejun Heo hlist_for_each_entry(worker, pos, &gcwq->busy_hash[i], hentry) 294db7bccf4STejun Heo 295f3421797STejun Heo static inline int __next_gcwq_cpu(int cpu, const struct cpumask *mask, 296f3421797STejun Heo unsigned int sw) 297f3421797STejun Heo { 298f3421797STejun Heo if (cpu < nr_cpu_ids) { 299f3421797STejun Heo if (sw & 1) { 300f3421797STejun Heo cpu = cpumask_next(cpu, mask); 301f3421797STejun Heo if (cpu < nr_cpu_ids) 302f3421797STejun Heo return cpu; 303f3421797STejun Heo } 304f3421797STejun Heo if (sw & 2) 305f3421797STejun Heo return WORK_CPU_UNBOUND; 306f3421797STejun Heo } 307f3421797STejun Heo return WORK_CPU_NONE; 308f3421797STejun Heo } 309f3421797STejun Heo 310f3421797STejun Heo static inline int __next_wq_cpu(int cpu, const struct cpumask *mask, 311f3421797STejun Heo struct workqueue_struct *wq) 312f3421797STejun Heo { 313f3421797STejun Heo return __next_gcwq_cpu(cpu, mask, !(wq->flags & WQ_UNBOUND) ? 1 : 2); 314f3421797STejun Heo } 315f3421797STejun Heo 31609884951STejun Heo /* 31709884951STejun Heo * CPU iterators 31809884951STejun Heo * 31909884951STejun Heo * An extra gcwq is defined for an invalid cpu number 32009884951STejun Heo * (WORK_CPU_UNBOUND) to host workqueues which are not bound to any 32109884951STejun Heo * specific CPU. The following iterators are similar to 32209884951STejun Heo * for_each_*_cpu() iterators but also considers the unbound gcwq. 32309884951STejun Heo * 32409884951STejun Heo * for_each_gcwq_cpu() : possible CPUs + WORK_CPU_UNBOUND 32509884951STejun Heo * for_each_online_gcwq_cpu() : online CPUs + WORK_CPU_UNBOUND 32609884951STejun Heo * for_each_cwq_cpu() : possible CPUs for bound workqueues, 32709884951STejun Heo * WORK_CPU_UNBOUND for unbound workqueues 32809884951STejun Heo */ 329f3421797STejun Heo #define for_each_gcwq_cpu(cpu) \ 330f3421797STejun Heo for ((cpu) = __next_gcwq_cpu(-1, cpu_possible_mask, 3); \ 331f3421797STejun Heo (cpu) < WORK_CPU_NONE; \ 332f3421797STejun Heo (cpu) = __next_gcwq_cpu((cpu), cpu_possible_mask, 3)) 333f3421797STejun Heo 334f3421797STejun Heo #define for_each_online_gcwq_cpu(cpu) \ 335f3421797STejun Heo for ((cpu) = __next_gcwq_cpu(-1, cpu_online_mask, 3); \ 336f3421797STejun Heo (cpu) < WORK_CPU_NONE; \ 337f3421797STejun Heo (cpu) = __next_gcwq_cpu((cpu), cpu_online_mask, 3)) 338f3421797STejun Heo 339f3421797STejun Heo #define for_each_cwq_cpu(cpu, wq) \ 340f3421797STejun Heo for ((cpu) = __next_wq_cpu(-1, cpu_possible_mask, (wq)); \ 341f3421797STejun Heo (cpu) < WORK_CPU_NONE; \ 342f3421797STejun Heo (cpu) = __next_wq_cpu((cpu), cpu_possible_mask, (wq))) 343f3421797STejun Heo 344dc186ad7SThomas Gleixner #ifdef CONFIG_DEBUG_OBJECTS_WORK 345dc186ad7SThomas Gleixner 346dc186ad7SThomas Gleixner static struct debug_obj_descr work_debug_descr; 347dc186ad7SThomas Gleixner 34899777288SStanislaw Gruszka static void *work_debug_hint(void *addr) 34999777288SStanislaw Gruszka { 35099777288SStanislaw Gruszka return ((struct work_struct *) addr)->func; 35199777288SStanislaw Gruszka } 35299777288SStanislaw Gruszka 353dc186ad7SThomas Gleixner /* 354dc186ad7SThomas Gleixner * fixup_init is called when: 355dc186ad7SThomas Gleixner * - an active object is initialized 356dc186ad7SThomas Gleixner */ 357dc186ad7SThomas Gleixner static int work_fixup_init(void *addr, enum debug_obj_state state) 358dc186ad7SThomas Gleixner { 359dc186ad7SThomas Gleixner struct work_struct *work = addr; 360dc186ad7SThomas Gleixner 361dc186ad7SThomas Gleixner switch (state) { 362dc186ad7SThomas Gleixner case ODEBUG_STATE_ACTIVE: 363dc186ad7SThomas Gleixner cancel_work_sync(work); 364dc186ad7SThomas Gleixner debug_object_init(work, &work_debug_descr); 365dc186ad7SThomas Gleixner return 1; 366dc186ad7SThomas Gleixner default: 367dc186ad7SThomas Gleixner return 0; 368dc186ad7SThomas Gleixner } 369dc186ad7SThomas Gleixner } 370dc186ad7SThomas Gleixner 371dc186ad7SThomas Gleixner /* 372dc186ad7SThomas Gleixner * fixup_activate is called when: 373dc186ad7SThomas Gleixner * - an active object is activated 374dc186ad7SThomas Gleixner * - an unknown object is activated (might be a statically initialized object) 375dc186ad7SThomas Gleixner */ 376dc186ad7SThomas Gleixner static int work_fixup_activate(void *addr, enum debug_obj_state state) 377dc186ad7SThomas Gleixner { 378dc186ad7SThomas Gleixner struct work_struct *work = addr; 379dc186ad7SThomas Gleixner 380dc186ad7SThomas Gleixner switch (state) { 381dc186ad7SThomas Gleixner 382dc186ad7SThomas Gleixner case ODEBUG_STATE_NOTAVAILABLE: 383dc186ad7SThomas Gleixner /* 384dc186ad7SThomas Gleixner * This is not really a fixup. The work struct was 385dc186ad7SThomas Gleixner * statically initialized. We just make sure that it 386dc186ad7SThomas Gleixner * is tracked in the object tracker. 387dc186ad7SThomas Gleixner */ 38822df02bbSTejun Heo if (test_bit(WORK_STRUCT_STATIC_BIT, work_data_bits(work))) { 389dc186ad7SThomas Gleixner debug_object_init(work, &work_debug_descr); 390dc186ad7SThomas Gleixner debug_object_activate(work, &work_debug_descr); 391dc186ad7SThomas Gleixner return 0; 392dc186ad7SThomas Gleixner } 393dc186ad7SThomas Gleixner WARN_ON_ONCE(1); 394dc186ad7SThomas Gleixner return 0; 395dc186ad7SThomas Gleixner 396dc186ad7SThomas Gleixner case ODEBUG_STATE_ACTIVE: 397dc186ad7SThomas Gleixner WARN_ON(1); 398dc186ad7SThomas Gleixner 399dc186ad7SThomas Gleixner default: 400dc186ad7SThomas Gleixner return 0; 401dc186ad7SThomas Gleixner } 402dc186ad7SThomas Gleixner } 403dc186ad7SThomas Gleixner 404dc186ad7SThomas Gleixner /* 405dc186ad7SThomas Gleixner * fixup_free is called when: 406dc186ad7SThomas Gleixner * - an active object is freed 407dc186ad7SThomas Gleixner */ 408dc186ad7SThomas Gleixner static int work_fixup_free(void *addr, enum debug_obj_state state) 409dc186ad7SThomas Gleixner { 410dc186ad7SThomas Gleixner struct work_struct *work = addr; 411dc186ad7SThomas Gleixner 412dc186ad7SThomas Gleixner switch (state) { 413dc186ad7SThomas Gleixner case ODEBUG_STATE_ACTIVE: 414dc186ad7SThomas Gleixner cancel_work_sync(work); 415dc186ad7SThomas Gleixner debug_object_free(work, &work_debug_descr); 416dc186ad7SThomas Gleixner return 1; 417dc186ad7SThomas Gleixner default: 418dc186ad7SThomas Gleixner return 0; 419dc186ad7SThomas Gleixner } 420dc186ad7SThomas Gleixner } 421dc186ad7SThomas Gleixner 422dc186ad7SThomas Gleixner static struct debug_obj_descr work_debug_descr = { 423dc186ad7SThomas Gleixner .name = "work_struct", 42499777288SStanislaw Gruszka .debug_hint = work_debug_hint, 425dc186ad7SThomas Gleixner .fixup_init = work_fixup_init, 426dc186ad7SThomas Gleixner .fixup_activate = work_fixup_activate, 427dc186ad7SThomas Gleixner .fixup_free = work_fixup_free, 428dc186ad7SThomas Gleixner }; 429dc186ad7SThomas Gleixner 430dc186ad7SThomas Gleixner static inline void debug_work_activate(struct work_struct *work) 431dc186ad7SThomas Gleixner { 432dc186ad7SThomas Gleixner debug_object_activate(work, &work_debug_descr); 433dc186ad7SThomas Gleixner } 434dc186ad7SThomas Gleixner 435dc186ad7SThomas Gleixner static inline void debug_work_deactivate(struct work_struct *work) 436dc186ad7SThomas Gleixner { 437dc186ad7SThomas Gleixner debug_object_deactivate(work, &work_debug_descr); 438dc186ad7SThomas Gleixner } 439dc186ad7SThomas Gleixner 440dc186ad7SThomas Gleixner void __init_work(struct work_struct *work, int onstack) 441dc186ad7SThomas Gleixner { 442dc186ad7SThomas Gleixner if (onstack) 443dc186ad7SThomas Gleixner debug_object_init_on_stack(work, &work_debug_descr); 444dc186ad7SThomas Gleixner else 445dc186ad7SThomas Gleixner debug_object_init(work, &work_debug_descr); 446dc186ad7SThomas Gleixner } 447dc186ad7SThomas Gleixner EXPORT_SYMBOL_GPL(__init_work); 448dc186ad7SThomas Gleixner 449dc186ad7SThomas Gleixner void destroy_work_on_stack(struct work_struct *work) 450dc186ad7SThomas Gleixner { 451dc186ad7SThomas Gleixner debug_object_free(work, &work_debug_descr); 452dc186ad7SThomas Gleixner } 453dc186ad7SThomas Gleixner EXPORT_SYMBOL_GPL(destroy_work_on_stack); 454dc186ad7SThomas Gleixner 455dc186ad7SThomas Gleixner #else 456dc186ad7SThomas Gleixner static inline void debug_work_activate(struct work_struct *work) { } 457dc186ad7SThomas Gleixner static inline void debug_work_deactivate(struct work_struct *work) { } 458dc186ad7SThomas Gleixner #endif 459dc186ad7SThomas Gleixner 46095402b38SGautham R Shenoy /* Serializes the accesses to the list of workqueues. */ 46195402b38SGautham R Shenoy static DEFINE_SPINLOCK(workqueue_lock); 4621da177e4SLinus Torvalds static LIST_HEAD(workqueues); 463a0a1a5fdSTejun Heo static bool workqueue_freezing; /* W: have wqs started freezing? */ 4641da177e4SLinus Torvalds 46514441960SOleg Nesterov /* 466e22bee78STejun Heo * The almighty global cpu workqueues. nr_running is the only field 467e22bee78STejun Heo * which is expected to be used frequently by other cpus via 468e22bee78STejun Heo * try_to_wake_up(). Put it in a separate cacheline. 46914441960SOleg Nesterov */ 4708b03ae3cSTejun Heo static DEFINE_PER_CPU(struct global_cwq, global_cwq); 4714ce62e9eSTejun Heo static DEFINE_PER_CPU_SHARED_ALIGNED(atomic_t, pool_nr_running[NR_WORKER_POOLS]); 472f756d5e2SNathan Lynch 473f3421797STejun Heo /* 474f3421797STejun Heo * Global cpu workqueue and nr_running counter for unbound gcwq. The 475f3421797STejun Heo * gcwq is always online, has GCWQ_DISASSOCIATED set, and all its 476f3421797STejun Heo * workers have WORKER_UNBOUND set. 477f3421797STejun Heo */ 478f3421797STejun Heo static struct global_cwq unbound_global_cwq; 4794ce62e9eSTejun Heo static atomic_t unbound_pool_nr_running[NR_WORKER_POOLS] = { 4804ce62e9eSTejun Heo [0 ... NR_WORKER_POOLS - 1] = ATOMIC_INIT(0), /* always 0 */ 4814ce62e9eSTejun Heo }; 482f3421797STejun Heo 483c34056a3STejun Heo static int worker_thread(void *__worker); 4841da177e4SLinus Torvalds 4853270476aSTejun Heo static int worker_pool_pri(struct worker_pool *pool) 4863270476aSTejun Heo { 4873270476aSTejun Heo return pool - pool->gcwq->pools; 4883270476aSTejun Heo } 4893270476aSTejun Heo 4908b03ae3cSTejun Heo static struct global_cwq *get_gcwq(unsigned int cpu) 4911da177e4SLinus Torvalds { 492f3421797STejun Heo if (cpu != WORK_CPU_UNBOUND) 4938b03ae3cSTejun Heo return &per_cpu(global_cwq, cpu); 494f3421797STejun Heo else 495f3421797STejun Heo return &unbound_global_cwq; 4961da177e4SLinus Torvalds } 4971da177e4SLinus Torvalds 49863d95a91STejun Heo static atomic_t *get_pool_nr_running(struct worker_pool *pool) 499b1f4ec17SOleg Nesterov { 50063d95a91STejun Heo int cpu = pool->gcwq->cpu; 5013270476aSTejun Heo int idx = worker_pool_pri(pool); 50263d95a91STejun Heo 503f3421797STejun Heo if (cpu != WORK_CPU_UNBOUND) 5044ce62e9eSTejun Heo return &per_cpu(pool_nr_running, cpu)[idx]; 505f3421797STejun Heo else 5064ce62e9eSTejun Heo return &unbound_pool_nr_running[idx]; 507b1f4ec17SOleg Nesterov } 508b1f4ec17SOleg Nesterov 5094690c4abSTejun Heo static struct cpu_workqueue_struct *get_cwq(unsigned int cpu, 5104690c4abSTejun Heo struct workqueue_struct *wq) 511a848e3b6SOleg Nesterov { 512f3421797STejun Heo if (!(wq->flags & WQ_UNBOUND)) { 513e06ffa1eSLai Jiangshan if (likely(cpu < nr_cpu_ids)) 514bdbc5dd7STejun Heo return per_cpu_ptr(wq->cpu_wq.pcpu, cpu); 515f3421797STejun Heo } else if (likely(cpu == WORK_CPU_UNBOUND)) 516f3421797STejun Heo return wq->cpu_wq.single; 517f3421797STejun Heo return NULL; 518f3421797STejun Heo } 519a848e3b6SOleg Nesterov 52073f53c4aSTejun Heo static unsigned int work_color_to_flags(int color) 52173f53c4aSTejun Heo { 52273f53c4aSTejun Heo return color << WORK_STRUCT_COLOR_SHIFT; 52373f53c4aSTejun Heo } 52473f53c4aSTejun Heo 52573f53c4aSTejun Heo static int get_work_color(struct work_struct *work) 52673f53c4aSTejun Heo { 52773f53c4aSTejun Heo return (*work_data_bits(work) >> WORK_STRUCT_COLOR_SHIFT) & 52873f53c4aSTejun Heo ((1 << WORK_STRUCT_COLOR_BITS) - 1); 52973f53c4aSTejun Heo } 53073f53c4aSTejun Heo 53173f53c4aSTejun Heo static int work_next_color(int color) 53273f53c4aSTejun Heo { 53373f53c4aSTejun Heo return (color + 1) % WORK_NR_COLORS; 5341da177e4SLinus Torvalds } 5351da177e4SLinus Torvalds 5364594bf15SDavid Howells /* 537b5490077STejun Heo * While queued, %WORK_STRUCT_CWQ is set and non flag bits of a work's data 538b5490077STejun Heo * contain the pointer to the queued cwq. Once execution starts, the flag 539b5490077STejun Heo * is cleared and the high bits contain OFFQ flags and CPU number. 5407a22ad75STejun Heo * 541bbb68dfaSTejun Heo * set_work_cwq(), set_work_cpu_and_clear_pending(), mark_work_canceling() 542bbb68dfaSTejun Heo * and clear_work_data() can be used to set the cwq, cpu or clear 543bbb68dfaSTejun Heo * work->data. These functions should only be called while the work is 544bbb68dfaSTejun Heo * owned - ie. while the PENDING bit is set. 5457a22ad75STejun Heo * 546bbb68dfaSTejun Heo * get_work_[g]cwq() can be used to obtain the gcwq or cwq corresponding to 547bbb68dfaSTejun Heo * a work. gcwq is available once the work has been queued anywhere after 548bbb68dfaSTejun Heo * initialization until it is sync canceled. cwq is available only while 549bbb68dfaSTejun Heo * the work item is queued. 550bbb68dfaSTejun Heo * 551bbb68dfaSTejun Heo * %WORK_OFFQ_CANCELING is used to mark a work item which is being 552bbb68dfaSTejun Heo * canceled. While being canceled, a work item may have its PENDING set 553bbb68dfaSTejun Heo * but stay off timer and worklist for arbitrarily long and nobody should 554bbb68dfaSTejun Heo * try to steal the PENDING bit. 5554594bf15SDavid Howells */ 5567a22ad75STejun Heo static inline void set_work_data(struct work_struct *work, unsigned long data, 5577a22ad75STejun Heo unsigned long flags) 5587a22ad75STejun Heo { 5597a22ad75STejun Heo BUG_ON(!work_pending(work)); 5607a22ad75STejun Heo atomic_long_set(&work->data, data | flags | work_static(work)); 5617a22ad75STejun Heo } 5627a22ad75STejun Heo 5637a22ad75STejun Heo static void set_work_cwq(struct work_struct *work, 5644690c4abSTejun Heo struct cpu_workqueue_struct *cwq, 5654690c4abSTejun Heo unsigned long extra_flags) 566365970a1SDavid Howells { 5677a22ad75STejun Heo set_work_data(work, (unsigned long)cwq, 568e120153dSTejun Heo WORK_STRUCT_PENDING | WORK_STRUCT_CWQ | extra_flags); 569365970a1SDavid Howells } 570365970a1SDavid Howells 5718930cabaSTejun Heo static void set_work_cpu_and_clear_pending(struct work_struct *work, 5728930cabaSTejun Heo unsigned int cpu) 5734d707b9fSOleg Nesterov { 57423657bb1STejun Heo /* 57523657bb1STejun Heo * The following wmb is paired with the implied mb in 57623657bb1STejun Heo * test_and_set_bit(PENDING) and ensures all updates to @work made 57723657bb1STejun Heo * here are visible to and precede any updates by the next PENDING 57823657bb1STejun Heo * owner. 57923657bb1STejun Heo */ 58023657bb1STejun Heo smp_wmb(); 581b5490077STejun Heo set_work_data(work, (unsigned long)cpu << WORK_OFFQ_CPU_SHIFT, 0); 5824d707b9fSOleg Nesterov } 5834d707b9fSOleg Nesterov 5847a22ad75STejun Heo static void clear_work_data(struct work_struct *work) 585365970a1SDavid Howells { 58623657bb1STejun Heo smp_wmb(); /* see set_work_cpu_and_clear_pending() */ 5877a22ad75STejun Heo set_work_data(work, WORK_STRUCT_NO_CPU, 0); 5887a22ad75STejun Heo } 5897a22ad75STejun Heo 5907a22ad75STejun Heo static struct cpu_workqueue_struct *get_work_cwq(struct work_struct *work) 5917a22ad75STejun Heo { 592e120153dSTejun Heo unsigned long data = atomic_long_read(&work->data); 5937a22ad75STejun Heo 594e120153dSTejun Heo if (data & WORK_STRUCT_CWQ) 595e120153dSTejun Heo return (void *)(data & WORK_STRUCT_WQ_DATA_MASK); 596e120153dSTejun Heo else 597e120153dSTejun Heo return NULL; 5987a22ad75STejun Heo } 5997a22ad75STejun Heo 6007a22ad75STejun Heo static struct global_cwq *get_work_gcwq(struct work_struct *work) 6017a22ad75STejun Heo { 602e120153dSTejun Heo unsigned long data = atomic_long_read(&work->data); 6037a22ad75STejun Heo unsigned int cpu; 6047a22ad75STejun Heo 605e120153dSTejun Heo if (data & WORK_STRUCT_CWQ) 606e120153dSTejun Heo return ((struct cpu_workqueue_struct *) 607bd7bdd43STejun Heo (data & WORK_STRUCT_WQ_DATA_MASK))->pool->gcwq; 6087a22ad75STejun Heo 609b5490077STejun Heo cpu = data >> WORK_OFFQ_CPU_SHIFT; 610bdbc5dd7STejun Heo if (cpu == WORK_CPU_NONE) 6117a22ad75STejun Heo return NULL; 6127a22ad75STejun Heo 613f3421797STejun Heo BUG_ON(cpu >= nr_cpu_ids && cpu != WORK_CPU_UNBOUND); 6147a22ad75STejun Heo return get_gcwq(cpu); 615365970a1SDavid Howells } 616365970a1SDavid Howells 617bbb68dfaSTejun Heo static void mark_work_canceling(struct work_struct *work) 618bbb68dfaSTejun Heo { 619bbb68dfaSTejun Heo struct global_cwq *gcwq = get_work_gcwq(work); 620bbb68dfaSTejun Heo unsigned long cpu = gcwq ? gcwq->cpu : WORK_CPU_NONE; 621bbb68dfaSTejun Heo 622bbb68dfaSTejun Heo set_work_data(work, (cpu << WORK_OFFQ_CPU_SHIFT) | WORK_OFFQ_CANCELING, 623bbb68dfaSTejun Heo WORK_STRUCT_PENDING); 624bbb68dfaSTejun Heo } 625bbb68dfaSTejun Heo 626bbb68dfaSTejun Heo static bool work_is_canceling(struct work_struct *work) 627bbb68dfaSTejun Heo { 628bbb68dfaSTejun Heo unsigned long data = atomic_long_read(&work->data); 629bbb68dfaSTejun Heo 630bbb68dfaSTejun Heo return !(data & WORK_STRUCT_CWQ) && (data & WORK_OFFQ_CANCELING); 631bbb68dfaSTejun Heo } 632bbb68dfaSTejun Heo 633e22bee78STejun Heo /* 6343270476aSTejun Heo * Policy functions. These define the policies on how the global worker 6353270476aSTejun Heo * pools are managed. Unless noted otherwise, these functions assume that 6363270476aSTejun Heo * they're being called with gcwq->lock held. 637e22bee78STejun Heo */ 638e22bee78STejun Heo 63963d95a91STejun Heo static bool __need_more_worker(struct worker_pool *pool) 640649027d7STejun Heo { 6413270476aSTejun Heo return !atomic_read(get_pool_nr_running(pool)); 642649027d7STejun Heo } 643649027d7STejun Heo 644e22bee78STejun Heo /* 645e22bee78STejun Heo * Need to wake up a worker? Called from anything but currently 646e22bee78STejun Heo * running workers. 647974271c4STejun Heo * 648974271c4STejun Heo * Note that, because unbound workers never contribute to nr_running, this 649974271c4STejun Heo * function will always return %true for unbound gcwq as long as the 650974271c4STejun Heo * worklist isn't empty. 651e22bee78STejun Heo */ 65263d95a91STejun Heo static bool need_more_worker(struct worker_pool *pool) 653e22bee78STejun Heo { 65463d95a91STejun Heo return !list_empty(&pool->worklist) && __need_more_worker(pool); 655e22bee78STejun Heo } 656e22bee78STejun Heo 657e22bee78STejun Heo /* Can I start working? Called from busy but !running workers. */ 65863d95a91STejun Heo static bool may_start_working(struct worker_pool *pool) 659e22bee78STejun Heo { 66063d95a91STejun Heo return pool->nr_idle; 661e22bee78STejun Heo } 662e22bee78STejun Heo 663e22bee78STejun Heo /* Do I need to keep working? Called from currently running workers. */ 66463d95a91STejun Heo static bool keep_working(struct worker_pool *pool) 665e22bee78STejun Heo { 66663d95a91STejun Heo atomic_t *nr_running = get_pool_nr_running(pool); 667e22bee78STejun Heo 6683270476aSTejun Heo return !list_empty(&pool->worklist) && atomic_read(nr_running) <= 1; 669e22bee78STejun Heo } 670e22bee78STejun Heo 671e22bee78STejun Heo /* Do we need a new worker? Called from manager. */ 67263d95a91STejun Heo static bool need_to_create_worker(struct worker_pool *pool) 673e22bee78STejun Heo { 67463d95a91STejun Heo return need_more_worker(pool) && !may_start_working(pool); 675e22bee78STejun Heo } 676e22bee78STejun Heo 677e22bee78STejun Heo /* Do I need to be the manager? */ 67863d95a91STejun Heo static bool need_to_manage_workers(struct worker_pool *pool) 679e22bee78STejun Heo { 68063d95a91STejun Heo return need_to_create_worker(pool) || 68111ebea50STejun Heo (pool->flags & POOL_MANAGE_WORKERS); 682e22bee78STejun Heo } 683e22bee78STejun Heo 684e22bee78STejun Heo /* Do we have too many workers and should some go away? */ 68563d95a91STejun Heo static bool too_many_workers(struct worker_pool *pool) 686e22bee78STejun Heo { 68760373152STejun Heo bool managing = mutex_is_locked(&pool->manager_mutex); 68863d95a91STejun Heo int nr_idle = pool->nr_idle + managing; /* manager is considered idle */ 68963d95a91STejun Heo int nr_busy = pool->nr_workers - nr_idle; 690e22bee78STejun Heo 691e22bee78STejun Heo return nr_idle > 2 && (nr_idle - 2) * MAX_IDLE_WORKERS_RATIO >= nr_busy; 692e22bee78STejun Heo } 693e22bee78STejun Heo 694e22bee78STejun Heo /* 695e22bee78STejun Heo * Wake up functions. 696e22bee78STejun Heo */ 697e22bee78STejun Heo 6987e11629dSTejun Heo /* Return the first worker. Safe with preemption disabled */ 69963d95a91STejun Heo static struct worker *first_worker(struct worker_pool *pool) 7007e11629dSTejun Heo { 70163d95a91STejun Heo if (unlikely(list_empty(&pool->idle_list))) 7027e11629dSTejun Heo return NULL; 7037e11629dSTejun Heo 70463d95a91STejun Heo return list_first_entry(&pool->idle_list, struct worker, entry); 7057e11629dSTejun Heo } 7067e11629dSTejun Heo 7077e11629dSTejun Heo /** 7087e11629dSTejun Heo * wake_up_worker - wake up an idle worker 70963d95a91STejun Heo * @pool: worker pool to wake worker from 7107e11629dSTejun Heo * 71163d95a91STejun Heo * Wake up the first idle worker of @pool. 7127e11629dSTejun Heo * 7137e11629dSTejun Heo * CONTEXT: 7147e11629dSTejun Heo * spin_lock_irq(gcwq->lock). 7157e11629dSTejun Heo */ 71663d95a91STejun Heo static void wake_up_worker(struct worker_pool *pool) 7177e11629dSTejun Heo { 71863d95a91STejun Heo struct worker *worker = first_worker(pool); 7197e11629dSTejun Heo 7207e11629dSTejun Heo if (likely(worker)) 7217e11629dSTejun Heo wake_up_process(worker->task); 7227e11629dSTejun Heo } 7237e11629dSTejun Heo 7244690c4abSTejun Heo /** 725e22bee78STejun Heo * wq_worker_waking_up - a worker is waking up 726e22bee78STejun Heo * @task: task waking up 727e22bee78STejun Heo * @cpu: CPU @task is waking up to 728e22bee78STejun Heo * 729e22bee78STejun Heo * This function is called during try_to_wake_up() when a worker is 730e22bee78STejun Heo * being awoken. 731e22bee78STejun Heo * 732e22bee78STejun Heo * CONTEXT: 733e22bee78STejun Heo * spin_lock_irq(rq->lock) 734e22bee78STejun Heo */ 735e22bee78STejun Heo void wq_worker_waking_up(struct task_struct *task, unsigned int cpu) 736e22bee78STejun Heo { 737e22bee78STejun Heo struct worker *worker = kthread_data(task); 738e22bee78STejun Heo 7392d64672eSSteven Rostedt if (!(worker->flags & WORKER_NOT_RUNNING)) 74063d95a91STejun Heo atomic_inc(get_pool_nr_running(worker->pool)); 741e22bee78STejun Heo } 742e22bee78STejun Heo 743e22bee78STejun Heo /** 744e22bee78STejun Heo * wq_worker_sleeping - a worker is going to sleep 745e22bee78STejun Heo * @task: task going to sleep 746e22bee78STejun Heo * @cpu: CPU in question, must be the current CPU number 747e22bee78STejun Heo * 748e22bee78STejun Heo * This function is called during schedule() when a busy worker is 749e22bee78STejun Heo * going to sleep. Worker on the same cpu can be woken up by 750e22bee78STejun Heo * returning pointer to its task. 751e22bee78STejun Heo * 752e22bee78STejun Heo * CONTEXT: 753e22bee78STejun Heo * spin_lock_irq(rq->lock) 754e22bee78STejun Heo * 755e22bee78STejun Heo * RETURNS: 756e22bee78STejun Heo * Worker task on @cpu to wake up, %NULL if none. 757e22bee78STejun Heo */ 758e22bee78STejun Heo struct task_struct *wq_worker_sleeping(struct task_struct *task, 759e22bee78STejun Heo unsigned int cpu) 760e22bee78STejun Heo { 761e22bee78STejun Heo struct worker *worker = kthread_data(task), *to_wakeup = NULL; 762bd7bdd43STejun Heo struct worker_pool *pool = worker->pool; 76363d95a91STejun Heo atomic_t *nr_running = get_pool_nr_running(pool); 764e22bee78STejun Heo 7652d64672eSSteven Rostedt if (worker->flags & WORKER_NOT_RUNNING) 766e22bee78STejun Heo return NULL; 767e22bee78STejun Heo 768e22bee78STejun Heo /* this can only happen on the local cpu */ 769e22bee78STejun Heo BUG_ON(cpu != raw_smp_processor_id()); 770e22bee78STejun Heo 771e22bee78STejun Heo /* 772e22bee78STejun Heo * The counterpart of the following dec_and_test, implied mb, 773e22bee78STejun Heo * worklist not empty test sequence is in insert_work(). 774e22bee78STejun Heo * Please read comment there. 775e22bee78STejun Heo * 776628c78e7STejun Heo * NOT_RUNNING is clear. This means that we're bound to and 777628c78e7STejun Heo * running on the local cpu w/ rq lock held and preemption 778628c78e7STejun Heo * disabled, which in turn means that none else could be 779628c78e7STejun Heo * manipulating idle_list, so dereferencing idle_list without gcwq 780628c78e7STejun Heo * lock is safe. 781e22bee78STejun Heo */ 782bd7bdd43STejun Heo if (atomic_dec_and_test(nr_running) && !list_empty(&pool->worklist)) 78363d95a91STejun Heo to_wakeup = first_worker(pool); 784e22bee78STejun Heo return to_wakeup ? to_wakeup->task : NULL; 785e22bee78STejun Heo } 786e22bee78STejun Heo 787e22bee78STejun Heo /** 788e22bee78STejun Heo * worker_set_flags - set worker flags and adjust nr_running accordingly 789cb444766STejun Heo * @worker: self 790d302f017STejun Heo * @flags: flags to set 791d302f017STejun Heo * @wakeup: wakeup an idle worker if necessary 792d302f017STejun Heo * 793e22bee78STejun Heo * Set @flags in @worker->flags and adjust nr_running accordingly. If 794e22bee78STejun Heo * nr_running becomes zero and @wakeup is %true, an idle worker is 795e22bee78STejun Heo * woken up. 796d302f017STejun Heo * 797cb444766STejun Heo * CONTEXT: 798cb444766STejun Heo * spin_lock_irq(gcwq->lock) 799d302f017STejun Heo */ 800d302f017STejun Heo static inline void worker_set_flags(struct worker *worker, unsigned int flags, 801d302f017STejun Heo bool wakeup) 802d302f017STejun Heo { 803bd7bdd43STejun Heo struct worker_pool *pool = worker->pool; 804e22bee78STejun Heo 805cb444766STejun Heo WARN_ON_ONCE(worker->task != current); 806cb444766STejun Heo 807e22bee78STejun Heo /* 808e22bee78STejun Heo * If transitioning into NOT_RUNNING, adjust nr_running and 809e22bee78STejun Heo * wake up an idle worker as necessary if requested by 810e22bee78STejun Heo * @wakeup. 811e22bee78STejun Heo */ 812e22bee78STejun Heo if ((flags & WORKER_NOT_RUNNING) && 813e22bee78STejun Heo !(worker->flags & WORKER_NOT_RUNNING)) { 81463d95a91STejun Heo atomic_t *nr_running = get_pool_nr_running(pool); 815e22bee78STejun Heo 816e22bee78STejun Heo if (wakeup) { 817e22bee78STejun Heo if (atomic_dec_and_test(nr_running) && 818bd7bdd43STejun Heo !list_empty(&pool->worklist)) 81963d95a91STejun Heo wake_up_worker(pool); 820e22bee78STejun Heo } else 821e22bee78STejun Heo atomic_dec(nr_running); 822e22bee78STejun Heo } 823e22bee78STejun Heo 824d302f017STejun Heo worker->flags |= flags; 825d302f017STejun Heo } 826d302f017STejun Heo 827d302f017STejun Heo /** 828e22bee78STejun Heo * worker_clr_flags - clear worker flags and adjust nr_running accordingly 829cb444766STejun Heo * @worker: self 830d302f017STejun Heo * @flags: flags to clear 831d302f017STejun Heo * 832e22bee78STejun Heo * Clear @flags in @worker->flags and adjust nr_running accordingly. 833d302f017STejun Heo * 834cb444766STejun Heo * CONTEXT: 835cb444766STejun Heo * spin_lock_irq(gcwq->lock) 836d302f017STejun Heo */ 837d302f017STejun Heo static inline void worker_clr_flags(struct worker *worker, unsigned int flags) 838d302f017STejun Heo { 83963d95a91STejun Heo struct worker_pool *pool = worker->pool; 840e22bee78STejun Heo unsigned int oflags = worker->flags; 841e22bee78STejun Heo 842cb444766STejun Heo WARN_ON_ONCE(worker->task != current); 843cb444766STejun Heo 844d302f017STejun Heo worker->flags &= ~flags; 845e22bee78STejun Heo 84642c025f3STejun Heo /* 84742c025f3STejun Heo * If transitioning out of NOT_RUNNING, increment nr_running. Note 84842c025f3STejun Heo * that the nested NOT_RUNNING is not a noop. NOT_RUNNING is mask 84942c025f3STejun Heo * of multiple flags, not a single flag. 85042c025f3STejun Heo */ 851e22bee78STejun Heo if ((flags & WORKER_NOT_RUNNING) && (oflags & WORKER_NOT_RUNNING)) 852e22bee78STejun Heo if (!(worker->flags & WORKER_NOT_RUNNING)) 85363d95a91STejun Heo atomic_inc(get_pool_nr_running(pool)); 854d302f017STejun Heo } 855d302f017STejun Heo 856d302f017STejun Heo /** 857c8e55f36STejun Heo * busy_worker_head - return the busy hash head for a work 858c8e55f36STejun Heo * @gcwq: gcwq of interest 859c8e55f36STejun Heo * @work: work to be hashed 860c8e55f36STejun Heo * 861c8e55f36STejun Heo * Return hash head of @gcwq for @work. 862c8e55f36STejun Heo * 863c8e55f36STejun Heo * CONTEXT: 864c8e55f36STejun Heo * spin_lock_irq(gcwq->lock). 865c8e55f36STejun Heo * 866c8e55f36STejun Heo * RETURNS: 867c8e55f36STejun Heo * Pointer to the hash head. 868c8e55f36STejun Heo */ 869c8e55f36STejun Heo static struct hlist_head *busy_worker_head(struct global_cwq *gcwq, 870c8e55f36STejun Heo struct work_struct *work) 871c8e55f36STejun Heo { 872c8e55f36STejun Heo const int base_shift = ilog2(sizeof(struct work_struct)); 873c8e55f36STejun Heo unsigned long v = (unsigned long)work; 874c8e55f36STejun Heo 875c8e55f36STejun Heo /* simple shift and fold hash, do we need something better? */ 876c8e55f36STejun Heo v >>= base_shift; 877c8e55f36STejun Heo v += v >> BUSY_WORKER_HASH_ORDER; 878c8e55f36STejun Heo v &= BUSY_WORKER_HASH_MASK; 879c8e55f36STejun Heo 880c8e55f36STejun Heo return &gcwq->busy_hash[v]; 881c8e55f36STejun Heo } 882c8e55f36STejun Heo 883c8e55f36STejun Heo /** 8848cca0eeaSTejun Heo * __find_worker_executing_work - find worker which is executing a work 8858cca0eeaSTejun Heo * @gcwq: gcwq of interest 8868cca0eeaSTejun Heo * @bwh: hash head as returned by busy_worker_head() 8878cca0eeaSTejun Heo * @work: work to find worker for 8888cca0eeaSTejun Heo * 8898cca0eeaSTejun Heo * Find a worker which is executing @work on @gcwq. @bwh should be 8908cca0eeaSTejun Heo * the hash head obtained by calling busy_worker_head() with the same 8918cca0eeaSTejun Heo * work. 8928cca0eeaSTejun Heo * 8938cca0eeaSTejun Heo * CONTEXT: 8948cca0eeaSTejun Heo * spin_lock_irq(gcwq->lock). 8958cca0eeaSTejun Heo * 8968cca0eeaSTejun Heo * RETURNS: 8978cca0eeaSTejun Heo * Pointer to worker which is executing @work if found, NULL 8988cca0eeaSTejun Heo * otherwise. 8998cca0eeaSTejun Heo */ 9008cca0eeaSTejun Heo static struct worker *__find_worker_executing_work(struct global_cwq *gcwq, 9018cca0eeaSTejun Heo struct hlist_head *bwh, 9028cca0eeaSTejun Heo struct work_struct *work) 9038cca0eeaSTejun Heo { 9048cca0eeaSTejun Heo struct worker *worker; 9058cca0eeaSTejun Heo struct hlist_node *tmp; 9068cca0eeaSTejun Heo 9078cca0eeaSTejun Heo hlist_for_each_entry(worker, tmp, bwh, hentry) 9088cca0eeaSTejun Heo if (worker->current_work == work) 9098cca0eeaSTejun Heo return worker; 9108cca0eeaSTejun Heo return NULL; 9118cca0eeaSTejun Heo } 9128cca0eeaSTejun Heo 9138cca0eeaSTejun Heo /** 9148cca0eeaSTejun Heo * find_worker_executing_work - find worker which is executing a work 9158cca0eeaSTejun Heo * @gcwq: gcwq of interest 9168cca0eeaSTejun Heo * @work: work to find worker for 9178cca0eeaSTejun Heo * 9188cca0eeaSTejun Heo * Find a worker which is executing @work on @gcwq. This function is 9198cca0eeaSTejun Heo * identical to __find_worker_executing_work() except that this 9208cca0eeaSTejun Heo * function calculates @bwh itself. 9218cca0eeaSTejun Heo * 9228cca0eeaSTejun Heo * CONTEXT: 9238cca0eeaSTejun Heo * spin_lock_irq(gcwq->lock). 9248cca0eeaSTejun Heo * 9258cca0eeaSTejun Heo * RETURNS: 9268cca0eeaSTejun Heo * Pointer to worker which is executing @work if found, NULL 9278cca0eeaSTejun Heo * otherwise. 9288cca0eeaSTejun Heo */ 9298cca0eeaSTejun Heo static struct worker *find_worker_executing_work(struct global_cwq *gcwq, 9308cca0eeaSTejun Heo struct work_struct *work) 9318cca0eeaSTejun Heo { 9328cca0eeaSTejun Heo return __find_worker_executing_work(gcwq, busy_worker_head(gcwq, work), 9338cca0eeaSTejun Heo work); 9348cca0eeaSTejun Heo } 9358cca0eeaSTejun Heo 9368cca0eeaSTejun Heo /** 937bf4ede01STejun Heo * move_linked_works - move linked works to a list 938bf4ede01STejun Heo * @work: start of series of works to be scheduled 939bf4ede01STejun Heo * @head: target list to append @work to 940bf4ede01STejun Heo * @nextp: out paramter for nested worklist walking 941bf4ede01STejun Heo * 942bf4ede01STejun Heo * Schedule linked works starting from @work to @head. Work series to 943bf4ede01STejun Heo * be scheduled starts at @work and includes any consecutive work with 944bf4ede01STejun Heo * WORK_STRUCT_LINKED set in its predecessor. 945bf4ede01STejun Heo * 946bf4ede01STejun Heo * If @nextp is not NULL, it's updated to point to the next work of 947bf4ede01STejun Heo * the last scheduled work. This allows move_linked_works() to be 948bf4ede01STejun Heo * nested inside outer list_for_each_entry_safe(). 949bf4ede01STejun Heo * 950bf4ede01STejun Heo * CONTEXT: 951bf4ede01STejun Heo * spin_lock_irq(gcwq->lock). 952bf4ede01STejun Heo */ 953bf4ede01STejun Heo static void move_linked_works(struct work_struct *work, struct list_head *head, 954bf4ede01STejun Heo struct work_struct **nextp) 955bf4ede01STejun Heo { 956bf4ede01STejun Heo struct work_struct *n; 957bf4ede01STejun Heo 958bf4ede01STejun Heo /* 959bf4ede01STejun Heo * Linked worklist will always end before the end of the list, 960bf4ede01STejun Heo * use NULL for list head. 961bf4ede01STejun Heo */ 962bf4ede01STejun Heo list_for_each_entry_safe_from(work, n, NULL, entry) { 963bf4ede01STejun Heo list_move_tail(&work->entry, head); 964bf4ede01STejun Heo if (!(*work_data_bits(work) & WORK_STRUCT_LINKED)) 965bf4ede01STejun Heo break; 966bf4ede01STejun Heo } 967bf4ede01STejun Heo 968bf4ede01STejun Heo /* 969bf4ede01STejun Heo * If we're already inside safe list traversal and have moved 970bf4ede01STejun Heo * multiple works to the scheduled queue, the next position 971bf4ede01STejun Heo * needs to be updated. 972bf4ede01STejun Heo */ 973bf4ede01STejun Heo if (nextp) 974bf4ede01STejun Heo *nextp = n; 975bf4ede01STejun Heo } 976bf4ede01STejun Heo 977bf4ede01STejun Heo static void cwq_activate_first_delayed(struct cpu_workqueue_struct *cwq) 978bf4ede01STejun Heo { 979bf4ede01STejun Heo struct work_struct *work = list_first_entry(&cwq->delayed_works, 980bf4ede01STejun Heo struct work_struct, entry); 981bf4ede01STejun Heo 982bf4ede01STejun Heo trace_workqueue_activate_work(work); 983bf4ede01STejun Heo move_linked_works(work, &cwq->pool->worklist, NULL); 984bf4ede01STejun Heo __clear_bit(WORK_STRUCT_DELAYED_BIT, work_data_bits(work)); 985bf4ede01STejun Heo cwq->nr_active++; 986bf4ede01STejun Heo } 987bf4ede01STejun Heo 988bf4ede01STejun Heo /** 989bf4ede01STejun Heo * cwq_dec_nr_in_flight - decrement cwq's nr_in_flight 990bf4ede01STejun Heo * @cwq: cwq of interest 991bf4ede01STejun Heo * @color: color of work which left the queue 992bf4ede01STejun Heo * @delayed: for a delayed work 993bf4ede01STejun Heo * 994bf4ede01STejun Heo * A work either has completed or is removed from pending queue, 995bf4ede01STejun Heo * decrement nr_in_flight of its cwq and handle workqueue flushing. 996bf4ede01STejun Heo * 997bf4ede01STejun Heo * CONTEXT: 998bf4ede01STejun Heo * spin_lock_irq(gcwq->lock). 999bf4ede01STejun Heo */ 1000bf4ede01STejun Heo static void cwq_dec_nr_in_flight(struct cpu_workqueue_struct *cwq, int color, 1001bf4ede01STejun Heo bool delayed) 1002bf4ede01STejun Heo { 1003bf4ede01STejun Heo /* ignore uncolored works */ 1004bf4ede01STejun Heo if (color == WORK_NO_COLOR) 1005bf4ede01STejun Heo return; 1006bf4ede01STejun Heo 1007bf4ede01STejun Heo cwq->nr_in_flight[color]--; 1008bf4ede01STejun Heo 1009bf4ede01STejun Heo if (!delayed) { 1010bf4ede01STejun Heo cwq->nr_active--; 1011bf4ede01STejun Heo if (!list_empty(&cwq->delayed_works)) { 1012bf4ede01STejun Heo /* one down, submit a delayed one */ 1013bf4ede01STejun Heo if (cwq->nr_active < cwq->max_active) 1014bf4ede01STejun Heo cwq_activate_first_delayed(cwq); 1015bf4ede01STejun Heo } 1016bf4ede01STejun Heo } 1017bf4ede01STejun Heo 1018bf4ede01STejun Heo /* is flush in progress and are we at the flushing tip? */ 1019bf4ede01STejun Heo if (likely(cwq->flush_color != color)) 1020bf4ede01STejun Heo return; 1021bf4ede01STejun Heo 1022bf4ede01STejun Heo /* are there still in-flight works? */ 1023bf4ede01STejun Heo if (cwq->nr_in_flight[color]) 1024bf4ede01STejun Heo return; 1025bf4ede01STejun Heo 1026bf4ede01STejun Heo /* this cwq is done, clear flush_color */ 1027bf4ede01STejun Heo cwq->flush_color = -1; 1028bf4ede01STejun Heo 1029bf4ede01STejun Heo /* 1030bf4ede01STejun Heo * If this was the last cwq, wake up the first flusher. It 1031bf4ede01STejun Heo * will handle the rest. 1032bf4ede01STejun Heo */ 1033bf4ede01STejun Heo if (atomic_dec_and_test(&cwq->wq->nr_cwqs_to_flush)) 1034bf4ede01STejun Heo complete(&cwq->wq->first_flusher->done); 1035bf4ede01STejun Heo } 1036bf4ede01STejun Heo 103736e227d2STejun Heo /** 1038bbb68dfaSTejun Heo * try_to_grab_pending - steal work item from worklist and disable irq 103936e227d2STejun Heo * @work: work item to steal 104036e227d2STejun Heo * @is_dwork: @work is a delayed_work 1041bbb68dfaSTejun Heo * @flags: place to store irq state 104236e227d2STejun Heo * 104336e227d2STejun Heo * Try to grab PENDING bit of @work. This function can handle @work in any 104436e227d2STejun Heo * stable state - idle, on timer or on worklist. Return values are 104536e227d2STejun Heo * 104636e227d2STejun Heo * 1 if @work was pending and we successfully stole PENDING 104736e227d2STejun Heo * 0 if @work was idle and we claimed PENDING 104836e227d2STejun Heo * -EAGAIN if PENDING couldn't be grabbed at the moment, safe to busy-retry 1049bbb68dfaSTejun Heo * -ENOENT if someone else is canceling @work, this state may persist 1050bbb68dfaSTejun Heo * for arbitrarily long 105136e227d2STejun Heo * 1052bbb68dfaSTejun Heo * On >= 0 return, the caller owns @work's PENDING bit. To avoid getting 1053bbb68dfaSTejun Heo * preempted while holding PENDING and @work off queue, preemption must be 1054bbb68dfaSTejun Heo * disabled on entry. This ensures that we don't return -EAGAIN while 1055bbb68dfaSTejun Heo * another task is preempted in this function. 1056bbb68dfaSTejun Heo * 1057bbb68dfaSTejun Heo * On successful return, >= 0, irq is disabled and the caller is 1058bbb68dfaSTejun Heo * responsible for releasing it using local_irq_restore(*@flags). 1059bbb68dfaSTejun Heo * 1060bbb68dfaSTejun Heo * This function is safe to call from any context other than IRQ handler. 1061bbb68dfaSTejun Heo * An IRQ handler may run on top of delayed_work_timer_fn() which can make 1062bbb68dfaSTejun Heo * this function return -EAGAIN perpetually. 1063bf4ede01STejun Heo */ 1064bbb68dfaSTejun Heo static int try_to_grab_pending(struct work_struct *work, bool is_dwork, 1065bbb68dfaSTejun Heo unsigned long *flags) 1066bf4ede01STejun Heo { 1067bf4ede01STejun Heo struct global_cwq *gcwq; 1068bf4ede01STejun Heo 1069bbb68dfaSTejun Heo WARN_ON_ONCE(in_irq()); 1070bbb68dfaSTejun Heo 1071bbb68dfaSTejun Heo local_irq_save(*flags); 1072bbb68dfaSTejun Heo 107336e227d2STejun Heo /* try to steal the timer if it exists */ 107436e227d2STejun Heo if (is_dwork) { 107536e227d2STejun Heo struct delayed_work *dwork = to_delayed_work(work); 107636e227d2STejun Heo 107736e227d2STejun Heo if (likely(del_timer(&dwork->timer))) 107836e227d2STejun Heo return 1; 107936e227d2STejun Heo } 108036e227d2STejun Heo 108136e227d2STejun Heo /* try to claim PENDING the normal way */ 1082bf4ede01STejun Heo if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) 1083bf4ede01STejun Heo return 0; 1084bf4ede01STejun Heo 1085bf4ede01STejun Heo /* 1086bf4ede01STejun Heo * The queueing is in progress, or it is already queued. Try to 1087bf4ede01STejun Heo * steal it from ->worklist without clearing WORK_STRUCT_PENDING. 1088bf4ede01STejun Heo */ 1089bf4ede01STejun Heo gcwq = get_work_gcwq(work); 1090bf4ede01STejun Heo if (!gcwq) 1091bbb68dfaSTejun Heo goto fail; 1092bf4ede01STejun Heo 1093bbb68dfaSTejun Heo spin_lock(&gcwq->lock); 1094bf4ede01STejun Heo if (!list_empty(&work->entry)) { 1095bf4ede01STejun Heo /* 1096bf4ede01STejun Heo * This work is queued, but perhaps we locked the wrong gcwq. 1097bf4ede01STejun Heo * In that case we must see the new value after rmb(), see 1098bf4ede01STejun Heo * insert_work()->wmb(). 1099bf4ede01STejun Heo */ 1100bf4ede01STejun Heo smp_rmb(); 1101bf4ede01STejun Heo if (gcwq == get_work_gcwq(work)) { 1102bf4ede01STejun Heo debug_work_deactivate(work); 1103bf4ede01STejun Heo list_del_init(&work->entry); 1104bf4ede01STejun Heo cwq_dec_nr_in_flight(get_work_cwq(work), 1105bf4ede01STejun Heo get_work_color(work), 1106bf4ede01STejun Heo *work_data_bits(work) & WORK_STRUCT_DELAYED); 110736e227d2STejun Heo 1108bbb68dfaSTejun Heo spin_unlock(&gcwq->lock); 110936e227d2STejun Heo return 1; 1110bf4ede01STejun Heo } 1111bf4ede01STejun Heo } 1112bbb68dfaSTejun Heo spin_unlock(&gcwq->lock); 1113bbb68dfaSTejun Heo fail: 1114bbb68dfaSTejun Heo local_irq_restore(*flags); 1115bbb68dfaSTejun Heo if (work_is_canceling(work)) 1116bbb68dfaSTejun Heo return -ENOENT; 1117bbb68dfaSTejun Heo cpu_relax(); 111836e227d2STejun Heo return -EAGAIN; 1119bf4ede01STejun Heo } 1120bf4ede01STejun Heo 1121bf4ede01STejun Heo /** 11227e11629dSTejun Heo * insert_work - insert a work into gcwq 11234690c4abSTejun Heo * @cwq: cwq @work belongs to 11244690c4abSTejun Heo * @work: work to insert 11254690c4abSTejun Heo * @head: insertion point 11264690c4abSTejun Heo * @extra_flags: extra WORK_STRUCT_* flags to set 11274690c4abSTejun Heo * 11287e11629dSTejun Heo * Insert @work which belongs to @cwq into @gcwq after @head. 11297e11629dSTejun Heo * @extra_flags is or'd to work_struct flags. 11304690c4abSTejun Heo * 11314690c4abSTejun Heo * CONTEXT: 11328b03ae3cSTejun Heo * spin_lock_irq(gcwq->lock). 11331da177e4SLinus Torvalds */ 1134b89deed3SOleg Nesterov static void insert_work(struct cpu_workqueue_struct *cwq, 11354690c4abSTejun Heo struct work_struct *work, struct list_head *head, 11364690c4abSTejun Heo unsigned int extra_flags) 1137b89deed3SOleg Nesterov { 113863d95a91STejun Heo struct worker_pool *pool = cwq->pool; 1139e1d8aa9fSFrederic Weisbecker 11404690c4abSTejun Heo /* we own @work, set data and link */ 11417a22ad75STejun Heo set_work_cwq(work, cwq, extra_flags); 11424690c4abSTejun Heo 11436e84d644SOleg Nesterov /* 11446e84d644SOleg Nesterov * Ensure that we get the right work->data if we see the 11456e84d644SOleg Nesterov * result of list_add() below, see try_to_grab_pending(). 11466e84d644SOleg Nesterov */ 11476e84d644SOleg Nesterov smp_wmb(); 11484690c4abSTejun Heo 11491a4d9b0aSOleg Nesterov list_add_tail(&work->entry, head); 1150e22bee78STejun Heo 1151e22bee78STejun Heo /* 1152e22bee78STejun Heo * Ensure either worker_sched_deactivated() sees the above 1153e22bee78STejun Heo * list_add_tail() or we see zero nr_running to avoid workers 1154e22bee78STejun Heo * lying around lazily while there are works to be processed. 1155e22bee78STejun Heo */ 1156e22bee78STejun Heo smp_mb(); 1157e22bee78STejun Heo 115863d95a91STejun Heo if (__need_more_worker(pool)) 115963d95a91STejun Heo wake_up_worker(pool); 1160b89deed3SOleg Nesterov } 1161b89deed3SOleg Nesterov 1162c8efcc25STejun Heo /* 1163c8efcc25STejun Heo * Test whether @work is being queued from another work executing on the 1164c8efcc25STejun Heo * same workqueue. This is rather expensive and should only be used from 1165c8efcc25STejun Heo * cold paths. 1166c8efcc25STejun Heo */ 1167c8efcc25STejun Heo static bool is_chained_work(struct workqueue_struct *wq) 1168c8efcc25STejun Heo { 1169c8efcc25STejun Heo unsigned long flags; 1170c8efcc25STejun Heo unsigned int cpu; 1171c8efcc25STejun Heo 1172c8efcc25STejun Heo for_each_gcwq_cpu(cpu) { 1173c8efcc25STejun Heo struct global_cwq *gcwq = get_gcwq(cpu); 1174c8efcc25STejun Heo struct worker *worker; 1175c8efcc25STejun Heo struct hlist_node *pos; 1176c8efcc25STejun Heo int i; 1177c8efcc25STejun Heo 1178c8efcc25STejun Heo spin_lock_irqsave(&gcwq->lock, flags); 1179c8efcc25STejun Heo for_each_busy_worker(worker, i, pos, gcwq) { 1180c8efcc25STejun Heo if (worker->task != current) 1181c8efcc25STejun Heo continue; 1182c8efcc25STejun Heo spin_unlock_irqrestore(&gcwq->lock, flags); 1183c8efcc25STejun Heo /* 1184c8efcc25STejun Heo * I'm @worker, no locking necessary. See if @work 1185c8efcc25STejun Heo * is headed to the same workqueue. 1186c8efcc25STejun Heo */ 1187c8efcc25STejun Heo return worker->current_cwq->wq == wq; 1188c8efcc25STejun Heo } 1189c8efcc25STejun Heo spin_unlock_irqrestore(&gcwq->lock, flags); 1190c8efcc25STejun Heo } 1191c8efcc25STejun Heo return false; 1192c8efcc25STejun Heo } 1193c8efcc25STejun Heo 11944690c4abSTejun Heo static void __queue_work(unsigned int cpu, struct workqueue_struct *wq, 11951da177e4SLinus Torvalds struct work_struct *work) 11961da177e4SLinus Torvalds { 1197502ca9d8STejun Heo struct global_cwq *gcwq; 1198502ca9d8STejun Heo struct cpu_workqueue_struct *cwq; 11991e19ffc6STejun Heo struct list_head *worklist; 12008a2e8e5dSTejun Heo unsigned int work_flags; 1201b75cac93SJoonsoo Kim unsigned int req_cpu = cpu; 12028930cabaSTejun Heo 12038930cabaSTejun Heo /* 12048930cabaSTejun Heo * While a work item is PENDING && off queue, a task trying to 12058930cabaSTejun Heo * steal the PENDING will busy-loop waiting for it to either get 12068930cabaSTejun Heo * queued or lose PENDING. Grabbing PENDING and queueing should 12078930cabaSTejun Heo * happen with IRQ disabled. 12088930cabaSTejun Heo */ 12098930cabaSTejun Heo WARN_ON_ONCE(!irqs_disabled()); 12101da177e4SLinus Torvalds 1211dc186ad7SThomas Gleixner debug_work_activate(work); 12121e19ffc6STejun Heo 1213c8efcc25STejun Heo /* if dying, only works from the same workqueue are allowed */ 12149c5a2ba7STejun Heo if (unlikely(wq->flags & WQ_DRAINING) && 1215c8efcc25STejun Heo WARN_ON_ONCE(!is_chained_work(wq))) 1216e41e704bSTejun Heo return; 1217e41e704bSTejun Heo 1218c7fc77f7STejun Heo /* determine gcwq to use */ 1219c7fc77f7STejun Heo if (!(wq->flags & WQ_UNBOUND)) { 1220c7fc77f7STejun Heo struct global_cwq *last_gcwq; 1221c7fc77f7STejun Heo 122257469821STejun Heo if (cpu == WORK_CPU_UNBOUND) 1223f3421797STejun Heo cpu = raw_smp_processor_id(); 1224f3421797STejun Heo 122518aa9effSTejun Heo /* 122618aa9effSTejun Heo * It's multi cpu. If @wq is non-reentrant and @work 122718aa9effSTejun Heo * was previously on a different cpu, it might still 122818aa9effSTejun Heo * be running there, in which case the work needs to 122918aa9effSTejun Heo * be queued on that cpu to guarantee non-reentrance. 123018aa9effSTejun Heo */ 1231502ca9d8STejun Heo gcwq = get_gcwq(cpu); 123218aa9effSTejun Heo if (wq->flags & WQ_NON_REENTRANT && 123318aa9effSTejun Heo (last_gcwq = get_work_gcwq(work)) && 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 13318930cabaSTejun Heo local_irq_disable(); 13321265057fSTejun Heo __queue_work(dwork->cpu, cwq->wq, &dwork->work); 13338930cabaSTejun Heo local_irq_enable(); 13341da177e4SLinus Torvalds } 1335d8e794dfSTejun Heo EXPORT_SYMBOL_GPL(delayed_work_timer_fn); 13361da177e4SLinus Torvalds 13377beb2edfSTejun Heo static void __queue_delayed_work(int cpu, struct workqueue_struct *wq, 13387beb2edfSTejun Heo struct delayed_work *dwork, unsigned long delay) 13397beb2edfSTejun Heo { 13407beb2edfSTejun Heo struct timer_list *timer = &dwork->timer; 13417beb2edfSTejun Heo struct work_struct *work = &dwork->work; 13427beb2edfSTejun Heo unsigned int lcpu; 13437beb2edfSTejun Heo 13447beb2edfSTejun Heo WARN_ON_ONCE(timer->function != delayed_work_timer_fn || 13457beb2edfSTejun Heo timer->data != (unsigned long)dwork); 13467beb2edfSTejun Heo BUG_ON(timer_pending(timer)); 13477beb2edfSTejun Heo BUG_ON(!list_empty(&work->entry)); 13487beb2edfSTejun Heo 13497beb2edfSTejun Heo timer_stats_timer_set_start_info(&dwork->timer); 13507beb2edfSTejun Heo 13517beb2edfSTejun Heo /* 13527beb2edfSTejun Heo * This stores cwq for the moment, for the timer_fn. Note that the 13537beb2edfSTejun Heo * work's gcwq is preserved to allow reentrance detection for 13547beb2edfSTejun Heo * delayed works. 13557beb2edfSTejun Heo */ 13567beb2edfSTejun Heo if (!(wq->flags & WQ_UNBOUND)) { 13577beb2edfSTejun Heo struct global_cwq *gcwq = get_work_gcwq(work); 13587beb2edfSTejun Heo 13597beb2edfSTejun Heo if (gcwq && gcwq->cpu != WORK_CPU_UNBOUND) 13607beb2edfSTejun Heo lcpu = gcwq->cpu; 13617beb2edfSTejun Heo else 13627beb2edfSTejun Heo lcpu = raw_smp_processor_id(); 13637beb2edfSTejun Heo } else { 13647beb2edfSTejun Heo lcpu = WORK_CPU_UNBOUND; 13657beb2edfSTejun Heo } 13667beb2edfSTejun Heo 13677beb2edfSTejun Heo set_work_cwq(work, get_cwq(lcpu, wq), 0); 13687beb2edfSTejun Heo 13691265057fSTejun Heo dwork->cpu = cpu; 13707beb2edfSTejun Heo timer->expires = jiffies + delay; 13717beb2edfSTejun Heo 13727beb2edfSTejun Heo if (unlikely(cpu != WORK_CPU_UNBOUND)) 13737beb2edfSTejun Heo add_timer_on(timer, cpu); 13747beb2edfSTejun Heo else 13757beb2edfSTejun Heo add_timer(timer); 13767beb2edfSTejun Heo } 13777beb2edfSTejun Heo 13780fcb78c2SRolf Eike Beer /** 13790fcb78c2SRolf Eike Beer * queue_delayed_work_on - queue work on specific CPU after delay 13800fcb78c2SRolf Eike Beer * @cpu: CPU number to execute work on 13810fcb78c2SRolf Eike Beer * @wq: workqueue to use 1382af9997e4SRandy Dunlap * @dwork: work to queue 13830fcb78c2SRolf Eike Beer * @delay: number of jiffies to wait before queueing 13840fcb78c2SRolf Eike Beer * 1385715f1300STejun Heo * Returns %false if @work was already on a queue, %true otherwise. If 1386715f1300STejun Heo * @delay is zero and @dwork is idle, it will be scheduled for immediate 1387715f1300STejun Heo * execution. 13880fcb78c2SRolf Eike Beer */ 1389d4283e93STejun Heo bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq, 139052bad64dSDavid Howells struct delayed_work *dwork, unsigned long delay) 13917a6bc1cdSVenkatesh Pallipadi { 139252bad64dSDavid Howells struct work_struct *work = &dwork->work; 1393d4283e93STejun Heo bool ret = false; 13948930cabaSTejun Heo unsigned long flags; 13958930cabaSTejun Heo 1396715f1300STejun Heo if (!delay) 1397715f1300STejun Heo return queue_work_on(cpu, wq, &dwork->work); 1398715f1300STejun Heo 13998930cabaSTejun Heo /* read the comment in __queue_work() */ 14008930cabaSTejun Heo local_irq_save(flags); 14017a6bc1cdSVenkatesh Pallipadi 140222df02bbSTejun Heo if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) { 14037beb2edfSTejun Heo __queue_delayed_work(cpu, wq, dwork, delay); 1404d4283e93STejun Heo ret = true; 14057a6bc1cdSVenkatesh Pallipadi } 14068930cabaSTejun Heo 14078930cabaSTejun Heo local_irq_restore(flags); 14087a6bc1cdSVenkatesh Pallipadi return ret; 14097a6bc1cdSVenkatesh Pallipadi } 1410ae90dd5dSDave Jones EXPORT_SYMBOL_GPL(queue_delayed_work_on); 14111da177e4SLinus Torvalds 1412c8e55f36STejun Heo /** 14130a13c00eSTejun Heo * queue_delayed_work - queue work on a workqueue after delay 14140a13c00eSTejun Heo * @wq: workqueue to use 14150a13c00eSTejun Heo * @dwork: delayable work to queue 14160a13c00eSTejun Heo * @delay: number of jiffies to wait before queueing 14170a13c00eSTejun Heo * 1418715f1300STejun Heo * Equivalent to queue_delayed_work_on() but tries to use the local CPU. 14190a13c00eSTejun Heo */ 1420d4283e93STejun Heo bool queue_delayed_work(struct workqueue_struct *wq, 14210a13c00eSTejun Heo struct delayed_work *dwork, unsigned long delay) 14220a13c00eSTejun Heo { 142357469821STejun Heo return queue_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay); 14240a13c00eSTejun Heo } 14250a13c00eSTejun Heo EXPORT_SYMBOL_GPL(queue_delayed_work); 14260a13c00eSTejun Heo 14270a13c00eSTejun Heo /** 14288376fe22STejun Heo * mod_delayed_work_on - modify delay of or queue a delayed work on specific CPU 14298376fe22STejun Heo * @cpu: CPU number to execute work on 14308376fe22STejun Heo * @wq: workqueue to use 14318376fe22STejun Heo * @dwork: work to queue 14328376fe22STejun Heo * @delay: number of jiffies to wait before queueing 14338376fe22STejun Heo * 14348376fe22STejun Heo * If @dwork is idle, equivalent to queue_delayed_work_on(); otherwise, 14358376fe22STejun Heo * modify @dwork's timer so that it expires after @delay. If @delay is 14368376fe22STejun Heo * zero, @work is guaranteed to be scheduled immediately regardless of its 14378376fe22STejun Heo * current state. 14388376fe22STejun Heo * 14398376fe22STejun Heo * Returns %false if @dwork was idle and queued, %true if @dwork was 14408376fe22STejun Heo * pending and its timer was modified. 14418376fe22STejun Heo * 14428376fe22STejun Heo * This function is safe to call from any context other than IRQ handler. 14438376fe22STejun Heo * See try_to_grab_pending() for details. 14448376fe22STejun Heo */ 14458376fe22STejun Heo bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq, 14468376fe22STejun Heo struct delayed_work *dwork, unsigned long delay) 14478376fe22STejun Heo { 14488376fe22STejun Heo unsigned long flags; 14498376fe22STejun Heo int ret; 14508376fe22STejun Heo 14518376fe22STejun Heo do { 14528376fe22STejun Heo ret = try_to_grab_pending(&dwork->work, true, &flags); 14538376fe22STejun Heo } while (unlikely(ret == -EAGAIN)); 14548376fe22STejun Heo 14558376fe22STejun Heo if (likely(ret >= 0)) { 14568376fe22STejun Heo __queue_delayed_work(cpu, wq, dwork, delay); 14578376fe22STejun Heo local_irq_restore(flags); 14588376fe22STejun Heo } 14598376fe22STejun Heo 14608376fe22STejun Heo /* -ENOENT from try_to_grab_pending() becomes %true */ 14618376fe22STejun Heo return ret; 14628376fe22STejun Heo } 14638376fe22STejun Heo EXPORT_SYMBOL_GPL(mod_delayed_work_on); 14648376fe22STejun Heo 14658376fe22STejun Heo /** 14668376fe22STejun Heo * mod_delayed_work - modify delay of or queue a delayed work 14678376fe22STejun Heo * @wq: workqueue to use 14688376fe22STejun Heo * @dwork: work to queue 14698376fe22STejun Heo * @delay: number of jiffies to wait before queueing 14708376fe22STejun Heo * 14718376fe22STejun Heo * mod_delayed_work_on() on local CPU. 14728376fe22STejun Heo */ 14738376fe22STejun Heo bool mod_delayed_work(struct workqueue_struct *wq, struct delayed_work *dwork, 14748376fe22STejun Heo unsigned long delay) 14758376fe22STejun Heo { 14768376fe22STejun Heo return mod_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay); 14778376fe22STejun Heo } 14788376fe22STejun Heo EXPORT_SYMBOL_GPL(mod_delayed_work); 14798376fe22STejun Heo 14808376fe22STejun Heo /** 1481c8e55f36STejun Heo * worker_enter_idle - enter idle state 1482c8e55f36STejun Heo * @worker: worker which is entering idle state 1483c8e55f36STejun Heo * 1484c8e55f36STejun Heo * @worker is entering idle state. Update stats and idle timer if 1485c8e55f36STejun Heo * necessary. 1486c8e55f36STejun Heo * 1487c8e55f36STejun Heo * LOCKING: 1488c8e55f36STejun Heo * spin_lock_irq(gcwq->lock). 1489c8e55f36STejun Heo */ 1490c8e55f36STejun Heo static void worker_enter_idle(struct worker *worker) 14911da177e4SLinus Torvalds { 1492bd7bdd43STejun Heo struct worker_pool *pool = worker->pool; 1493bd7bdd43STejun Heo struct global_cwq *gcwq = pool->gcwq; 1494c8e55f36STejun Heo 1495c8e55f36STejun Heo BUG_ON(worker->flags & WORKER_IDLE); 1496c8e55f36STejun Heo BUG_ON(!list_empty(&worker->entry) && 1497c8e55f36STejun Heo (worker->hentry.next || worker->hentry.pprev)); 1498c8e55f36STejun Heo 1499cb444766STejun Heo /* can't use worker_set_flags(), also called from start_worker() */ 1500cb444766STejun Heo worker->flags |= WORKER_IDLE; 1501bd7bdd43STejun Heo pool->nr_idle++; 1502e22bee78STejun Heo worker->last_active = jiffies; 1503c8e55f36STejun Heo 1504c8e55f36STejun Heo /* idle_list is LIFO */ 1505bd7bdd43STejun Heo list_add(&worker->entry, &pool->idle_list); 1506db7bccf4STejun Heo 150763d95a91STejun Heo if (too_many_workers(pool) && !timer_pending(&pool->idle_timer)) 1508628c78e7STejun Heo mod_timer(&pool->idle_timer, jiffies + IDLE_WORKER_TIMEOUT); 1509cb444766STejun Heo 1510544ecf31STejun Heo /* 1511628c78e7STejun Heo * Sanity check nr_running. Because gcwq_unbind_fn() releases 1512628c78e7STejun Heo * gcwq->lock between setting %WORKER_UNBOUND and zapping 1513628c78e7STejun Heo * nr_running, the warning may trigger spuriously. Check iff 1514628c78e7STejun Heo * unbind is not in progress. 1515544ecf31STejun Heo */ 1516628c78e7STejun Heo WARN_ON_ONCE(!(gcwq->flags & GCWQ_DISASSOCIATED) && 1517bd7bdd43STejun Heo pool->nr_workers == pool->nr_idle && 151863d95a91STejun Heo atomic_read(get_pool_nr_running(pool))); 1519c8e55f36STejun Heo } 1520c8e55f36STejun Heo 1521c8e55f36STejun Heo /** 1522c8e55f36STejun Heo * worker_leave_idle - leave idle state 1523c8e55f36STejun Heo * @worker: worker which is leaving idle state 1524c8e55f36STejun Heo * 1525c8e55f36STejun Heo * @worker is leaving idle state. Update stats. 1526c8e55f36STejun Heo * 1527c8e55f36STejun Heo * LOCKING: 1528c8e55f36STejun Heo * spin_lock_irq(gcwq->lock). 1529c8e55f36STejun Heo */ 1530c8e55f36STejun Heo static void worker_leave_idle(struct worker *worker) 1531c8e55f36STejun Heo { 1532bd7bdd43STejun Heo struct worker_pool *pool = worker->pool; 1533c8e55f36STejun Heo 1534c8e55f36STejun Heo BUG_ON(!(worker->flags & WORKER_IDLE)); 1535d302f017STejun Heo worker_clr_flags(worker, WORKER_IDLE); 1536bd7bdd43STejun Heo pool->nr_idle--; 1537c8e55f36STejun Heo list_del_init(&worker->entry); 1538c8e55f36STejun Heo } 1539c8e55f36STejun Heo 1540e22bee78STejun Heo /** 1541e22bee78STejun Heo * worker_maybe_bind_and_lock - bind worker to its cpu if possible and lock gcwq 1542e22bee78STejun Heo * @worker: self 1543e22bee78STejun Heo * 1544e22bee78STejun Heo * Works which are scheduled while the cpu is online must at least be 1545e22bee78STejun Heo * scheduled to a worker which is bound to the cpu so that if they are 1546e22bee78STejun Heo * flushed from cpu callbacks while cpu is going down, they are 1547e22bee78STejun Heo * guaranteed to execute on the cpu. 1548e22bee78STejun Heo * 1549e22bee78STejun Heo * This function is to be used by rogue workers and rescuers to bind 1550e22bee78STejun Heo * themselves to the target cpu and may race with cpu going down or 1551e22bee78STejun Heo * coming online. kthread_bind() can't be used because it may put the 1552e22bee78STejun Heo * worker to already dead cpu and set_cpus_allowed_ptr() can't be used 1553e22bee78STejun Heo * verbatim as it's best effort and blocking and gcwq may be 1554e22bee78STejun Heo * [dis]associated in the meantime. 1555e22bee78STejun Heo * 1556f2d5a0eeSTejun Heo * This function tries set_cpus_allowed() and locks gcwq and verifies the 1557f2d5a0eeSTejun Heo * binding against %GCWQ_DISASSOCIATED which is set during 1558f2d5a0eeSTejun Heo * %CPU_DOWN_PREPARE and cleared during %CPU_ONLINE, so if the worker 1559f2d5a0eeSTejun Heo * enters idle state or fetches works without dropping lock, it can 1560f2d5a0eeSTejun Heo * guarantee the scheduling requirement described in the first paragraph. 1561e22bee78STejun Heo * 1562e22bee78STejun Heo * CONTEXT: 1563e22bee78STejun Heo * Might sleep. Called without any lock but returns with gcwq->lock 1564e22bee78STejun Heo * held. 1565e22bee78STejun Heo * 1566e22bee78STejun Heo * RETURNS: 1567e22bee78STejun Heo * %true if the associated gcwq is online (@worker is successfully 1568e22bee78STejun Heo * bound), %false if offline. 1569e22bee78STejun Heo */ 1570e22bee78STejun Heo static bool worker_maybe_bind_and_lock(struct worker *worker) 1571972fa1c5SNamhyung Kim __acquires(&gcwq->lock) 1572e22bee78STejun Heo { 1573bd7bdd43STejun Heo struct global_cwq *gcwq = worker->pool->gcwq; 1574e22bee78STejun Heo struct task_struct *task = worker->task; 1575e22bee78STejun Heo 1576e22bee78STejun Heo while (true) { 1577e22bee78STejun Heo /* 1578e22bee78STejun Heo * The following call may fail, succeed or succeed 1579e22bee78STejun Heo * without actually migrating the task to the cpu if 1580e22bee78STejun Heo * it races with cpu hotunplug operation. Verify 1581e22bee78STejun Heo * against GCWQ_DISASSOCIATED. 1582e22bee78STejun Heo */ 1583f3421797STejun Heo if (!(gcwq->flags & GCWQ_DISASSOCIATED)) 1584e22bee78STejun Heo set_cpus_allowed_ptr(task, get_cpu_mask(gcwq->cpu)); 1585e22bee78STejun Heo 1586e22bee78STejun Heo spin_lock_irq(&gcwq->lock); 1587e22bee78STejun Heo if (gcwq->flags & GCWQ_DISASSOCIATED) 1588e22bee78STejun Heo return false; 1589e22bee78STejun Heo if (task_cpu(task) == gcwq->cpu && 1590e22bee78STejun Heo cpumask_equal(¤t->cpus_allowed, 1591e22bee78STejun Heo get_cpu_mask(gcwq->cpu))) 1592e22bee78STejun Heo return true; 1593e22bee78STejun Heo spin_unlock_irq(&gcwq->lock); 1594e22bee78STejun Heo 15955035b20fSTejun Heo /* 15965035b20fSTejun Heo * We've raced with CPU hot[un]plug. Give it a breather 15975035b20fSTejun Heo * and retry migration. cond_resched() is required here; 15985035b20fSTejun Heo * otherwise, we might deadlock against cpu_stop trying to 15995035b20fSTejun Heo * bring down the CPU on non-preemptive kernel. 16005035b20fSTejun Heo */ 1601e22bee78STejun Heo cpu_relax(); 16025035b20fSTejun Heo cond_resched(); 1603e22bee78STejun Heo } 1604e22bee78STejun Heo } 1605e22bee78STejun Heo 160625511a47STejun Heo struct idle_rebind { 160725511a47STejun Heo int cnt; /* # workers to be rebound */ 160825511a47STejun Heo struct completion done; /* all workers rebound */ 160925511a47STejun Heo }; 161025511a47STejun Heo 1611e22bee78STejun Heo /* 161225511a47STejun Heo * Rebind an idle @worker to its CPU. During CPU onlining, this has to 161325511a47STejun Heo * happen synchronously for idle workers. worker_thread() will test 161425511a47STejun Heo * %WORKER_REBIND before leaving idle and call this function. 161525511a47STejun Heo */ 161625511a47STejun Heo static void idle_worker_rebind(struct worker *worker) 161725511a47STejun Heo { 161825511a47STejun Heo struct global_cwq *gcwq = worker->pool->gcwq; 161925511a47STejun Heo 162025511a47STejun Heo /* CPU must be online at this point */ 162125511a47STejun Heo WARN_ON(!worker_maybe_bind_and_lock(worker)); 162225511a47STejun Heo if (!--worker->idle_rebind->cnt) 162325511a47STejun Heo complete(&worker->idle_rebind->done); 162425511a47STejun Heo spin_unlock_irq(&worker->pool->gcwq->lock); 162525511a47STejun Heo 162625511a47STejun Heo /* we did our part, wait for rebind_workers() to finish up */ 162725511a47STejun Heo wait_event(gcwq->rebind_hold, !(worker->flags & WORKER_REBIND)); 162825511a47STejun Heo } 162925511a47STejun Heo 163025511a47STejun Heo /* 163125511a47STejun Heo * Function for @worker->rebind.work used to rebind unbound busy workers to 1632403c821dSTejun Heo * the associated cpu which is coming back online. This is scheduled by 1633403c821dSTejun Heo * cpu up but can race with other cpu hotplug operations and may be 1634403c821dSTejun Heo * executed twice without intervening cpu down. 1635e22bee78STejun Heo */ 163625511a47STejun Heo static void busy_worker_rebind_fn(struct work_struct *work) 1637e22bee78STejun Heo { 1638e22bee78STejun Heo struct worker *worker = container_of(work, struct worker, rebind_work); 1639bd7bdd43STejun Heo struct global_cwq *gcwq = worker->pool->gcwq; 1640e22bee78STejun Heo 1641e22bee78STejun Heo if (worker_maybe_bind_and_lock(worker)) 1642e22bee78STejun Heo worker_clr_flags(worker, WORKER_REBIND); 1643e22bee78STejun Heo 1644e22bee78STejun Heo spin_unlock_irq(&gcwq->lock); 1645e22bee78STejun Heo } 1646e22bee78STejun Heo 164725511a47STejun Heo /** 164825511a47STejun Heo * rebind_workers - rebind all workers of a gcwq to the associated CPU 164925511a47STejun Heo * @gcwq: gcwq of interest 165025511a47STejun Heo * 165125511a47STejun Heo * @gcwq->cpu is coming online. Rebind all workers to the CPU. Rebinding 165225511a47STejun Heo * is different for idle and busy ones. 165325511a47STejun Heo * 165425511a47STejun Heo * The idle ones should be rebound synchronously and idle rebinding should 165525511a47STejun Heo * be complete before any worker starts executing work items with 165625511a47STejun Heo * concurrency management enabled; otherwise, scheduler may oops trying to 165725511a47STejun Heo * wake up non-local idle worker from wq_worker_sleeping(). 165825511a47STejun Heo * 165925511a47STejun Heo * This is achieved by repeatedly requesting rebinding until all idle 166025511a47STejun Heo * workers are known to have been rebound under @gcwq->lock and holding all 166125511a47STejun Heo * idle workers from becoming busy until idle rebinding is complete. 166225511a47STejun Heo * 166325511a47STejun Heo * Once idle workers are rebound, busy workers can be rebound as they 166425511a47STejun Heo * finish executing their current work items. Queueing the rebind work at 166525511a47STejun Heo * the head of their scheduled lists is enough. Note that nr_running will 166625511a47STejun Heo * be properbly bumped as busy workers rebind. 166725511a47STejun Heo * 166825511a47STejun Heo * On return, all workers are guaranteed to either be bound or have rebind 166925511a47STejun Heo * work item scheduled. 167025511a47STejun Heo */ 167125511a47STejun Heo static void rebind_workers(struct global_cwq *gcwq) 167225511a47STejun Heo __releases(&gcwq->lock) __acquires(&gcwq->lock) 167325511a47STejun Heo { 167425511a47STejun Heo struct idle_rebind idle_rebind; 167525511a47STejun Heo struct worker_pool *pool; 167625511a47STejun Heo struct worker *worker; 167725511a47STejun Heo struct hlist_node *pos; 167825511a47STejun Heo int i; 167925511a47STejun Heo 168025511a47STejun Heo lockdep_assert_held(&gcwq->lock); 168125511a47STejun Heo 168225511a47STejun Heo for_each_worker_pool(pool, gcwq) 168325511a47STejun Heo lockdep_assert_held(&pool->manager_mutex); 168425511a47STejun Heo 168525511a47STejun Heo /* 168625511a47STejun Heo * Rebind idle workers. Interlocked both ways. We wait for 168725511a47STejun Heo * workers to rebind via @idle_rebind.done. Workers will wait for 168825511a47STejun Heo * us to finish up by watching %WORKER_REBIND. 168925511a47STejun Heo */ 169025511a47STejun Heo init_completion(&idle_rebind.done); 169125511a47STejun Heo retry: 169225511a47STejun Heo idle_rebind.cnt = 1; 169325511a47STejun Heo INIT_COMPLETION(idle_rebind.done); 169425511a47STejun Heo 169525511a47STejun Heo /* set REBIND and kick idle ones, we'll wait for these later */ 169625511a47STejun Heo for_each_worker_pool(pool, gcwq) { 169725511a47STejun Heo list_for_each_entry(worker, &pool->idle_list, entry) { 169825511a47STejun Heo if (worker->flags & WORKER_REBIND) 169925511a47STejun Heo continue; 170025511a47STejun Heo 170125511a47STejun Heo /* morph UNBOUND to REBIND */ 170225511a47STejun Heo worker->flags &= ~WORKER_UNBOUND; 170325511a47STejun Heo worker->flags |= WORKER_REBIND; 170425511a47STejun Heo 170525511a47STejun Heo idle_rebind.cnt++; 170625511a47STejun Heo worker->idle_rebind = &idle_rebind; 170725511a47STejun Heo 170825511a47STejun Heo /* worker_thread() will call idle_worker_rebind() */ 170925511a47STejun Heo wake_up_process(worker->task); 171025511a47STejun Heo } 171125511a47STejun Heo } 171225511a47STejun Heo 171325511a47STejun Heo if (--idle_rebind.cnt) { 171425511a47STejun Heo spin_unlock_irq(&gcwq->lock); 171525511a47STejun Heo wait_for_completion(&idle_rebind.done); 171625511a47STejun Heo spin_lock_irq(&gcwq->lock); 171725511a47STejun Heo /* busy ones might have become idle while waiting, retry */ 171825511a47STejun Heo goto retry; 171925511a47STejun Heo } 172025511a47STejun Heo 172125511a47STejun Heo /* 172225511a47STejun Heo * All idle workers are rebound and waiting for %WORKER_REBIND to 172325511a47STejun Heo * be cleared inside idle_worker_rebind(). Clear and release. 172425511a47STejun Heo * Clearing %WORKER_REBIND from this foreign context is safe 172525511a47STejun Heo * because these workers are still guaranteed to be idle. 172625511a47STejun Heo */ 172725511a47STejun Heo for_each_worker_pool(pool, gcwq) 172825511a47STejun Heo list_for_each_entry(worker, &pool->idle_list, entry) 172925511a47STejun Heo worker->flags &= ~WORKER_REBIND; 173025511a47STejun Heo 173125511a47STejun Heo wake_up_all(&gcwq->rebind_hold); 173225511a47STejun Heo 173325511a47STejun Heo /* rebind busy workers */ 173425511a47STejun Heo for_each_busy_worker(worker, i, pos, gcwq) { 173525511a47STejun Heo struct work_struct *rebind_work = &worker->rebind_work; 173625511a47STejun Heo 173725511a47STejun Heo /* morph UNBOUND to REBIND */ 173825511a47STejun Heo worker->flags &= ~WORKER_UNBOUND; 173925511a47STejun Heo worker->flags |= WORKER_REBIND; 174025511a47STejun Heo 174125511a47STejun Heo if (test_and_set_bit(WORK_STRUCT_PENDING_BIT, 174225511a47STejun Heo work_data_bits(rebind_work))) 174325511a47STejun Heo continue; 174425511a47STejun Heo 174525511a47STejun Heo /* wq doesn't matter, use the default one */ 174625511a47STejun Heo debug_work_activate(rebind_work); 174725511a47STejun Heo insert_work(get_cwq(gcwq->cpu, system_wq), rebind_work, 174825511a47STejun Heo worker->scheduled.next, 174925511a47STejun Heo work_color_to_flags(WORK_NO_COLOR)); 175025511a47STejun Heo } 175125511a47STejun Heo } 175225511a47STejun Heo 1753c34056a3STejun Heo static struct worker *alloc_worker(void) 1754c34056a3STejun Heo { 1755c34056a3STejun Heo struct worker *worker; 1756c34056a3STejun Heo 1757c34056a3STejun Heo worker = kzalloc(sizeof(*worker), GFP_KERNEL); 1758c8e55f36STejun Heo if (worker) { 1759c8e55f36STejun Heo INIT_LIST_HEAD(&worker->entry); 1760affee4b2STejun Heo INIT_LIST_HEAD(&worker->scheduled); 176125511a47STejun Heo INIT_WORK(&worker->rebind_work, busy_worker_rebind_fn); 1762e22bee78STejun Heo /* on creation a worker is in !idle && prep state */ 1763e22bee78STejun Heo worker->flags = WORKER_PREP; 1764c8e55f36STejun Heo } 1765c34056a3STejun Heo return worker; 1766c34056a3STejun Heo } 1767c34056a3STejun Heo 1768c34056a3STejun Heo /** 1769c34056a3STejun Heo * create_worker - create a new workqueue worker 177063d95a91STejun Heo * @pool: pool the new worker will belong to 1771c34056a3STejun Heo * 177263d95a91STejun Heo * Create a new worker which is bound to @pool. The returned worker 1773c34056a3STejun Heo * can be started by calling start_worker() or destroyed using 1774c34056a3STejun Heo * destroy_worker(). 1775c34056a3STejun Heo * 1776c34056a3STejun Heo * CONTEXT: 1777c34056a3STejun Heo * Might sleep. Does GFP_KERNEL allocations. 1778c34056a3STejun Heo * 1779c34056a3STejun Heo * RETURNS: 1780c34056a3STejun Heo * Pointer to the newly created worker. 1781c34056a3STejun Heo */ 1782bc2ae0f5STejun Heo static struct worker *create_worker(struct worker_pool *pool) 1783c34056a3STejun Heo { 178463d95a91STejun Heo struct global_cwq *gcwq = pool->gcwq; 17853270476aSTejun Heo const char *pri = worker_pool_pri(pool) ? "H" : ""; 1786c34056a3STejun Heo struct worker *worker = NULL; 1787f3421797STejun Heo int id = -1; 1788c34056a3STejun Heo 17898b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 1790bd7bdd43STejun Heo while (ida_get_new(&pool->worker_ida, &id)) { 17918b03ae3cSTejun Heo spin_unlock_irq(&gcwq->lock); 1792bd7bdd43STejun Heo if (!ida_pre_get(&pool->worker_ida, GFP_KERNEL)) 1793c34056a3STejun Heo goto fail; 17948b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 1795c34056a3STejun Heo } 17968b03ae3cSTejun Heo spin_unlock_irq(&gcwq->lock); 1797c34056a3STejun Heo 1798c34056a3STejun Heo worker = alloc_worker(); 1799c34056a3STejun Heo if (!worker) 1800c34056a3STejun Heo goto fail; 1801c34056a3STejun Heo 1802bd7bdd43STejun Heo worker->pool = pool; 1803c34056a3STejun Heo worker->id = id; 1804c34056a3STejun Heo 1805bc2ae0f5STejun Heo if (gcwq->cpu != WORK_CPU_UNBOUND) 180694dcf29aSEric Dumazet worker->task = kthread_create_on_node(worker_thread, 18073270476aSTejun Heo worker, cpu_to_node(gcwq->cpu), 18083270476aSTejun Heo "kworker/%u:%d%s", gcwq->cpu, id, pri); 1809f3421797STejun Heo else 1810f3421797STejun Heo worker->task = kthread_create(worker_thread, worker, 18113270476aSTejun Heo "kworker/u:%d%s", id, pri); 1812c34056a3STejun Heo if (IS_ERR(worker->task)) 1813c34056a3STejun Heo goto fail; 1814c34056a3STejun Heo 18153270476aSTejun Heo if (worker_pool_pri(pool)) 18163270476aSTejun Heo set_user_nice(worker->task, HIGHPRI_NICE_LEVEL); 18173270476aSTejun Heo 1818db7bccf4STejun Heo /* 1819bc2ae0f5STejun Heo * Determine CPU binding of the new worker depending on 1820bc2ae0f5STejun Heo * %GCWQ_DISASSOCIATED. The caller is responsible for ensuring the 1821bc2ae0f5STejun Heo * flag remains stable across this function. See the comments 1822bc2ae0f5STejun Heo * above the flag definition for details. 1823bc2ae0f5STejun Heo * 1824bc2ae0f5STejun Heo * As an unbound worker may later become a regular one if CPU comes 1825bc2ae0f5STejun Heo * online, make sure every worker has %PF_THREAD_BOUND set. 1826db7bccf4STejun Heo */ 1827bc2ae0f5STejun Heo if (!(gcwq->flags & GCWQ_DISASSOCIATED)) { 18288b03ae3cSTejun Heo kthread_bind(worker->task, gcwq->cpu); 1829bc2ae0f5STejun Heo } else { 1830db7bccf4STejun Heo worker->task->flags |= PF_THREAD_BOUND; 1831f3421797STejun Heo worker->flags |= WORKER_UNBOUND; 1832f3421797STejun Heo } 1833c34056a3STejun Heo 1834c34056a3STejun Heo return worker; 1835c34056a3STejun Heo fail: 1836c34056a3STejun Heo if (id >= 0) { 18378b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 1838bd7bdd43STejun Heo ida_remove(&pool->worker_ida, id); 18398b03ae3cSTejun Heo spin_unlock_irq(&gcwq->lock); 1840c34056a3STejun Heo } 1841c34056a3STejun Heo kfree(worker); 1842c34056a3STejun Heo return NULL; 1843c34056a3STejun Heo } 1844c34056a3STejun Heo 1845c34056a3STejun Heo /** 1846c34056a3STejun Heo * start_worker - start a newly created worker 1847c34056a3STejun Heo * @worker: worker to start 1848c34056a3STejun Heo * 1849c8e55f36STejun Heo * Make the gcwq aware of @worker and start it. 1850c34056a3STejun Heo * 1851c34056a3STejun Heo * CONTEXT: 18528b03ae3cSTejun Heo * spin_lock_irq(gcwq->lock). 1853c34056a3STejun Heo */ 1854c34056a3STejun Heo static void start_worker(struct worker *worker) 1855c34056a3STejun Heo { 1856cb444766STejun Heo worker->flags |= WORKER_STARTED; 1857bd7bdd43STejun Heo worker->pool->nr_workers++; 1858c8e55f36STejun Heo worker_enter_idle(worker); 1859c34056a3STejun Heo wake_up_process(worker->task); 1860c34056a3STejun Heo } 1861c34056a3STejun Heo 1862c34056a3STejun Heo /** 1863c34056a3STejun Heo * destroy_worker - destroy a workqueue worker 1864c34056a3STejun Heo * @worker: worker to be destroyed 1865c34056a3STejun Heo * 1866c8e55f36STejun Heo * Destroy @worker and adjust @gcwq stats accordingly. 1867c8e55f36STejun Heo * 1868c8e55f36STejun Heo * CONTEXT: 1869c8e55f36STejun Heo * spin_lock_irq(gcwq->lock) which is released and regrabbed. 1870c34056a3STejun Heo */ 1871c34056a3STejun Heo static void destroy_worker(struct worker *worker) 1872c34056a3STejun Heo { 1873bd7bdd43STejun Heo struct worker_pool *pool = worker->pool; 1874bd7bdd43STejun Heo struct global_cwq *gcwq = pool->gcwq; 1875c34056a3STejun Heo int id = worker->id; 1876c34056a3STejun Heo 1877c34056a3STejun Heo /* sanity check frenzy */ 1878c34056a3STejun Heo BUG_ON(worker->current_work); 1879affee4b2STejun Heo BUG_ON(!list_empty(&worker->scheduled)); 1880c34056a3STejun Heo 1881c8e55f36STejun Heo if (worker->flags & WORKER_STARTED) 1882bd7bdd43STejun Heo pool->nr_workers--; 1883c8e55f36STejun Heo if (worker->flags & WORKER_IDLE) 1884bd7bdd43STejun Heo pool->nr_idle--; 1885c8e55f36STejun Heo 1886c8e55f36STejun Heo list_del_init(&worker->entry); 1887cb444766STejun Heo worker->flags |= WORKER_DIE; 1888c8e55f36STejun Heo 1889c8e55f36STejun Heo spin_unlock_irq(&gcwq->lock); 1890c8e55f36STejun Heo 1891c34056a3STejun Heo kthread_stop(worker->task); 1892c34056a3STejun Heo kfree(worker); 1893c34056a3STejun Heo 18948b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 1895bd7bdd43STejun Heo ida_remove(&pool->worker_ida, id); 1896c34056a3STejun Heo } 1897c34056a3STejun Heo 189863d95a91STejun Heo static void idle_worker_timeout(unsigned long __pool) 1899e22bee78STejun Heo { 190063d95a91STejun Heo struct worker_pool *pool = (void *)__pool; 190163d95a91STejun Heo struct global_cwq *gcwq = pool->gcwq; 1902e22bee78STejun Heo 1903e22bee78STejun Heo spin_lock_irq(&gcwq->lock); 1904e22bee78STejun Heo 190563d95a91STejun Heo if (too_many_workers(pool)) { 1906e22bee78STejun Heo struct worker *worker; 1907e22bee78STejun Heo unsigned long expires; 1908e22bee78STejun Heo 1909e22bee78STejun Heo /* idle_list is kept in LIFO order, check the last one */ 191063d95a91STejun Heo worker = list_entry(pool->idle_list.prev, struct worker, entry); 1911e22bee78STejun Heo expires = worker->last_active + IDLE_WORKER_TIMEOUT; 1912e22bee78STejun Heo 1913e22bee78STejun Heo if (time_before(jiffies, expires)) 191463d95a91STejun Heo mod_timer(&pool->idle_timer, expires); 1915e22bee78STejun Heo else { 1916e22bee78STejun Heo /* it's been idle for too long, wake up manager */ 191711ebea50STejun Heo pool->flags |= POOL_MANAGE_WORKERS; 191863d95a91STejun Heo wake_up_worker(pool); 1919e22bee78STejun Heo } 1920e22bee78STejun Heo } 1921e22bee78STejun Heo 1922e22bee78STejun Heo spin_unlock_irq(&gcwq->lock); 1923e22bee78STejun Heo } 1924e22bee78STejun Heo 1925e22bee78STejun Heo static bool send_mayday(struct work_struct *work) 1926e22bee78STejun Heo { 1927e22bee78STejun Heo struct cpu_workqueue_struct *cwq = get_work_cwq(work); 1928e22bee78STejun Heo struct workqueue_struct *wq = cwq->wq; 1929f3421797STejun Heo unsigned int cpu; 1930e22bee78STejun Heo 1931e22bee78STejun Heo if (!(wq->flags & WQ_RESCUER)) 1932e22bee78STejun Heo return false; 1933e22bee78STejun Heo 1934e22bee78STejun Heo /* mayday mayday mayday */ 1935bd7bdd43STejun Heo cpu = cwq->pool->gcwq->cpu; 1936f3421797STejun Heo /* WORK_CPU_UNBOUND can't be set in cpumask, use cpu 0 instead */ 1937f3421797STejun Heo if (cpu == WORK_CPU_UNBOUND) 1938f3421797STejun Heo cpu = 0; 1939f2e005aaSTejun Heo if (!mayday_test_and_set_cpu(cpu, wq->mayday_mask)) 1940e22bee78STejun Heo wake_up_process(wq->rescuer->task); 1941e22bee78STejun Heo return true; 1942e22bee78STejun Heo } 1943e22bee78STejun Heo 194463d95a91STejun Heo static void gcwq_mayday_timeout(unsigned long __pool) 1945e22bee78STejun Heo { 194663d95a91STejun Heo struct worker_pool *pool = (void *)__pool; 194763d95a91STejun Heo struct global_cwq *gcwq = pool->gcwq; 1948e22bee78STejun Heo struct work_struct *work; 1949e22bee78STejun Heo 1950e22bee78STejun Heo spin_lock_irq(&gcwq->lock); 1951e22bee78STejun Heo 195263d95a91STejun Heo if (need_to_create_worker(pool)) { 1953e22bee78STejun Heo /* 1954e22bee78STejun Heo * We've been trying to create a new worker but 1955e22bee78STejun Heo * haven't been successful. We might be hitting an 1956e22bee78STejun Heo * allocation deadlock. Send distress signals to 1957e22bee78STejun Heo * rescuers. 1958e22bee78STejun Heo */ 195963d95a91STejun Heo list_for_each_entry(work, &pool->worklist, entry) 1960e22bee78STejun Heo send_mayday(work); 1961e22bee78STejun Heo } 1962e22bee78STejun Heo 1963e22bee78STejun Heo spin_unlock_irq(&gcwq->lock); 1964e22bee78STejun Heo 196563d95a91STejun Heo mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INTERVAL); 1966e22bee78STejun Heo } 1967e22bee78STejun Heo 1968e22bee78STejun Heo /** 1969e22bee78STejun Heo * maybe_create_worker - create a new worker if necessary 197063d95a91STejun Heo * @pool: pool to create a new worker for 1971e22bee78STejun Heo * 197263d95a91STejun Heo * Create a new worker for @pool if necessary. @pool is guaranteed to 1973e22bee78STejun Heo * have at least one idle worker on return from this function. If 1974e22bee78STejun Heo * creating a new worker takes longer than MAYDAY_INTERVAL, mayday is 197563d95a91STejun Heo * sent to all rescuers with works scheduled on @pool to resolve 1976e22bee78STejun Heo * possible allocation deadlock. 1977e22bee78STejun Heo * 1978e22bee78STejun Heo * On return, need_to_create_worker() is guaranteed to be false and 1979e22bee78STejun Heo * may_start_working() true. 1980e22bee78STejun Heo * 1981e22bee78STejun Heo * LOCKING: 1982e22bee78STejun Heo * spin_lock_irq(gcwq->lock) which may be released and regrabbed 1983e22bee78STejun Heo * multiple times. Does GFP_KERNEL allocations. Called only from 1984e22bee78STejun Heo * manager. 1985e22bee78STejun Heo * 1986e22bee78STejun Heo * RETURNS: 1987e22bee78STejun Heo * false if no action was taken and gcwq->lock stayed locked, true 1988e22bee78STejun Heo * otherwise. 1989e22bee78STejun Heo */ 199063d95a91STejun Heo static bool maybe_create_worker(struct worker_pool *pool) 199106bd6ebfSNamhyung Kim __releases(&gcwq->lock) 199206bd6ebfSNamhyung Kim __acquires(&gcwq->lock) 1993e22bee78STejun Heo { 199463d95a91STejun Heo struct global_cwq *gcwq = pool->gcwq; 199563d95a91STejun Heo 199663d95a91STejun Heo if (!need_to_create_worker(pool)) 1997e22bee78STejun Heo return false; 1998e22bee78STejun Heo restart: 19999f9c2364STejun Heo spin_unlock_irq(&gcwq->lock); 20009f9c2364STejun Heo 2001e22bee78STejun Heo /* if we don't make progress in MAYDAY_INITIAL_TIMEOUT, call for help */ 200263d95a91STejun Heo mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INITIAL_TIMEOUT); 2003e22bee78STejun Heo 2004e22bee78STejun Heo while (true) { 2005e22bee78STejun Heo struct worker *worker; 2006e22bee78STejun Heo 2007bc2ae0f5STejun Heo worker = create_worker(pool); 2008e22bee78STejun Heo if (worker) { 200963d95a91STejun Heo del_timer_sync(&pool->mayday_timer); 2010e22bee78STejun Heo spin_lock_irq(&gcwq->lock); 2011e22bee78STejun Heo start_worker(worker); 201263d95a91STejun Heo BUG_ON(need_to_create_worker(pool)); 2013e22bee78STejun Heo return true; 2014e22bee78STejun Heo } 2015e22bee78STejun Heo 201663d95a91STejun Heo if (!need_to_create_worker(pool)) 2017e22bee78STejun Heo break; 2018e22bee78STejun Heo 2019e22bee78STejun Heo __set_current_state(TASK_INTERRUPTIBLE); 2020e22bee78STejun Heo schedule_timeout(CREATE_COOLDOWN); 20219f9c2364STejun Heo 202263d95a91STejun Heo if (!need_to_create_worker(pool)) 2023e22bee78STejun Heo break; 2024e22bee78STejun Heo } 2025e22bee78STejun Heo 202663d95a91STejun Heo del_timer_sync(&pool->mayday_timer); 2027e22bee78STejun Heo spin_lock_irq(&gcwq->lock); 202863d95a91STejun Heo if (need_to_create_worker(pool)) 2029e22bee78STejun Heo goto restart; 2030e22bee78STejun Heo return true; 2031e22bee78STejun Heo } 2032e22bee78STejun Heo 2033e22bee78STejun Heo /** 2034e22bee78STejun Heo * maybe_destroy_worker - destroy workers which have been idle for a while 203563d95a91STejun Heo * @pool: pool to destroy workers for 2036e22bee78STejun Heo * 203763d95a91STejun Heo * Destroy @pool workers which have been idle for longer than 2038e22bee78STejun Heo * IDLE_WORKER_TIMEOUT. 2039e22bee78STejun Heo * 2040e22bee78STejun Heo * LOCKING: 2041e22bee78STejun Heo * spin_lock_irq(gcwq->lock) which may be released and regrabbed 2042e22bee78STejun Heo * multiple times. Called only from manager. 2043e22bee78STejun Heo * 2044e22bee78STejun Heo * RETURNS: 2045e22bee78STejun Heo * false if no action was taken and gcwq->lock stayed locked, true 2046e22bee78STejun Heo * otherwise. 2047e22bee78STejun Heo */ 204863d95a91STejun Heo static bool maybe_destroy_workers(struct worker_pool *pool) 2049e22bee78STejun Heo { 2050e22bee78STejun Heo bool ret = false; 2051e22bee78STejun Heo 205263d95a91STejun Heo while (too_many_workers(pool)) { 2053e22bee78STejun Heo struct worker *worker; 2054e22bee78STejun Heo unsigned long expires; 2055e22bee78STejun Heo 205663d95a91STejun Heo worker = list_entry(pool->idle_list.prev, struct worker, entry); 2057e22bee78STejun Heo expires = worker->last_active + IDLE_WORKER_TIMEOUT; 2058e22bee78STejun Heo 2059e22bee78STejun Heo if (time_before(jiffies, expires)) { 206063d95a91STejun Heo mod_timer(&pool->idle_timer, expires); 2061e22bee78STejun Heo break; 2062e22bee78STejun Heo } 2063e22bee78STejun Heo 2064e22bee78STejun Heo destroy_worker(worker); 2065e22bee78STejun Heo ret = true; 2066e22bee78STejun Heo } 2067e22bee78STejun Heo 2068e22bee78STejun Heo return ret; 2069e22bee78STejun Heo } 2070e22bee78STejun Heo 2071e22bee78STejun Heo /** 2072e22bee78STejun Heo * manage_workers - manage worker pool 2073e22bee78STejun Heo * @worker: self 2074e22bee78STejun Heo * 2075e22bee78STejun Heo * Assume the manager role and manage gcwq worker pool @worker belongs 2076e22bee78STejun Heo * to. At any given time, there can be only zero or one manager per 2077e22bee78STejun Heo * gcwq. The exclusion is handled automatically by this function. 2078e22bee78STejun Heo * 2079e22bee78STejun Heo * The caller can safely start processing works on false return. On 2080e22bee78STejun Heo * true return, it's guaranteed that need_to_create_worker() is false 2081e22bee78STejun Heo * and may_start_working() is true. 2082e22bee78STejun Heo * 2083e22bee78STejun Heo * CONTEXT: 2084e22bee78STejun Heo * spin_lock_irq(gcwq->lock) which may be released and regrabbed 2085e22bee78STejun Heo * multiple times. Does GFP_KERNEL allocations. 2086e22bee78STejun Heo * 2087e22bee78STejun Heo * RETURNS: 2088e22bee78STejun Heo * false if no action was taken and gcwq->lock stayed locked, true if 2089e22bee78STejun Heo * some action was taken. 2090e22bee78STejun Heo */ 2091e22bee78STejun Heo static bool manage_workers(struct worker *worker) 2092e22bee78STejun Heo { 209363d95a91STejun Heo struct worker_pool *pool = worker->pool; 2094e22bee78STejun Heo bool ret = false; 2095e22bee78STejun Heo 209660373152STejun Heo if (!mutex_trylock(&pool->manager_mutex)) 2097e22bee78STejun Heo return ret; 2098e22bee78STejun Heo 209911ebea50STejun Heo pool->flags &= ~POOL_MANAGE_WORKERS; 2100e22bee78STejun Heo 2101e22bee78STejun Heo /* 2102e22bee78STejun Heo * Destroy and then create so that may_start_working() is true 2103e22bee78STejun Heo * on return. 2104e22bee78STejun Heo */ 210563d95a91STejun Heo ret |= maybe_destroy_workers(pool); 210663d95a91STejun Heo ret |= maybe_create_worker(pool); 2107e22bee78STejun Heo 210860373152STejun Heo mutex_unlock(&pool->manager_mutex); 2109e22bee78STejun Heo return ret; 2110e22bee78STejun Heo } 2111e22bee78STejun Heo 2112a62428c0STejun Heo /** 2113a62428c0STejun Heo * process_one_work - process single work 2114c34056a3STejun Heo * @worker: self 2115a62428c0STejun Heo * @work: work to process 2116a62428c0STejun Heo * 2117a62428c0STejun Heo * Process @work. This function contains all the logics necessary to 2118a62428c0STejun Heo * process a single work including synchronization against and 2119a62428c0STejun Heo * interaction with other workers on the same cpu, queueing and 2120a62428c0STejun Heo * flushing. As long as context requirement is met, any worker can 2121a62428c0STejun Heo * call this function to process a work. 2122a62428c0STejun Heo * 2123a62428c0STejun Heo * CONTEXT: 21248b03ae3cSTejun Heo * spin_lock_irq(gcwq->lock) which is released and regrabbed. 2125a62428c0STejun Heo */ 2126c34056a3STejun Heo static void process_one_work(struct worker *worker, struct work_struct *work) 212706bd6ebfSNamhyung Kim __releases(&gcwq->lock) 212806bd6ebfSNamhyung Kim __acquires(&gcwq->lock) 21291da177e4SLinus Torvalds { 21307e11629dSTejun Heo struct cpu_workqueue_struct *cwq = get_work_cwq(work); 2131bd7bdd43STejun Heo struct worker_pool *pool = worker->pool; 2132bd7bdd43STejun Heo struct global_cwq *gcwq = pool->gcwq; 2133c8e55f36STejun Heo struct hlist_head *bwh = busy_worker_head(gcwq, work); 2134fb0e7bebSTejun Heo bool cpu_intensive = cwq->wq->flags & WQ_CPU_INTENSIVE; 21356bb49e59SDavid Howells work_func_t f = work->func; 213673f53c4aSTejun Heo int work_color; 21377e11629dSTejun Heo struct worker *collision; 21384e6045f1SJohannes Berg #ifdef CONFIG_LOCKDEP 21394e6045f1SJohannes Berg /* 2140a62428c0STejun Heo * It is permissible to free the struct work_struct from 2141a62428c0STejun Heo * inside the function that is called from it, this we need to 2142a62428c0STejun Heo * take into account for lockdep too. To avoid bogus "held 2143a62428c0STejun Heo * lock freed" warnings as well as problems when looking into 2144a62428c0STejun Heo * work->lockdep_map, make a copy and use that here. 21454e6045f1SJohannes Berg */ 21464d82a1deSPeter Zijlstra struct lockdep_map lockdep_map; 21474d82a1deSPeter Zijlstra 21484d82a1deSPeter Zijlstra lockdep_copy_map(&lockdep_map, &work->lockdep_map); 21494e6045f1SJohannes Berg #endif 21506fec10a1STejun Heo /* 21516fec10a1STejun Heo * Ensure we're on the correct CPU. DISASSOCIATED test is 21526fec10a1STejun Heo * necessary to avoid spurious warnings from rescuers servicing the 21536fec10a1STejun Heo * unbound or a disassociated gcwq. 21546fec10a1STejun Heo */ 215525511a47STejun Heo WARN_ON_ONCE(!(worker->flags & (WORKER_UNBOUND | WORKER_REBIND)) && 21566fec10a1STejun Heo !(gcwq->flags & GCWQ_DISASSOCIATED) && 215725511a47STejun Heo raw_smp_processor_id() != gcwq->cpu); 215825511a47STejun Heo 21597e11629dSTejun Heo /* 21607e11629dSTejun Heo * A single work shouldn't be executed concurrently by 21617e11629dSTejun Heo * multiple workers on a single cpu. Check whether anyone is 21627e11629dSTejun Heo * already processing the work. If so, defer the work to the 21637e11629dSTejun Heo * currently executing one. 21647e11629dSTejun Heo */ 21657e11629dSTejun Heo collision = __find_worker_executing_work(gcwq, bwh, work); 21667e11629dSTejun Heo if (unlikely(collision)) { 21677e11629dSTejun Heo move_linked_works(work, &collision->scheduled, NULL); 21687e11629dSTejun Heo return; 21697e11629dSTejun Heo } 21701da177e4SLinus Torvalds 21718930cabaSTejun Heo /* claim and dequeue */ 21721da177e4SLinus Torvalds debug_work_deactivate(work); 2173c8e55f36STejun Heo hlist_add_head(&worker->hentry, bwh); 2174c34056a3STejun Heo worker->current_work = work; 21758cca0eeaSTejun Heo worker->current_cwq = cwq; 217673f53c4aSTejun Heo work_color = get_work_color(work); 21777a22ad75STejun Heo 2178a62428c0STejun Heo list_del_init(&work->entry); 2179a62428c0STejun Heo 2180649027d7STejun Heo /* 2181fb0e7bebSTejun Heo * CPU intensive works don't participate in concurrency 2182fb0e7bebSTejun Heo * management. They're the scheduler's responsibility. 2183fb0e7bebSTejun Heo */ 2184fb0e7bebSTejun Heo if (unlikely(cpu_intensive)) 2185fb0e7bebSTejun Heo worker_set_flags(worker, WORKER_CPU_INTENSIVE, true); 2186fb0e7bebSTejun Heo 2187974271c4STejun Heo /* 2188974271c4STejun Heo * Unbound gcwq isn't concurrency managed and work items should be 2189974271c4STejun Heo * executed ASAP. Wake up another worker if necessary. 2190974271c4STejun Heo */ 219163d95a91STejun Heo if ((worker->flags & WORKER_UNBOUND) && need_more_worker(pool)) 219263d95a91STejun Heo wake_up_worker(pool); 2193974271c4STejun Heo 21948930cabaSTejun Heo /* 219523657bb1STejun Heo * Record the last CPU and clear PENDING which should be the last 219623657bb1STejun Heo * update to @work. Also, do this inside @gcwq->lock so that 219723657bb1STejun Heo * PENDING and queued state changes happen together while IRQ is 219823657bb1STejun Heo * disabled. 21998930cabaSTejun Heo */ 22008930cabaSTejun Heo set_work_cpu_and_clear_pending(work, gcwq->cpu); 22011da177e4SLinus Torvalds 22028930cabaSTejun Heo spin_unlock_irq(&gcwq->lock); 2203959d1af8STejun Heo 2204e159489bSTejun Heo lock_map_acquire_read(&cwq->wq->lockdep_map); 22053295f0efSIngo Molnar lock_map_acquire(&lockdep_map); 2206e36c886aSArjan van de Ven trace_workqueue_execute_start(work); 220765f27f38SDavid Howells f(work); 2208e36c886aSArjan van de Ven /* 2209e36c886aSArjan van de Ven * While we must be careful to not use "work" after this, the trace 2210e36c886aSArjan van de Ven * point will only record its address. 2211e36c886aSArjan van de Ven */ 2212e36c886aSArjan van de Ven trace_workqueue_execute_end(work); 22133295f0efSIngo Molnar lock_map_release(&lockdep_map); 22143295f0efSIngo Molnar lock_map_release(&cwq->wq->lockdep_map); 22151da177e4SLinus Torvalds 2216d5abe669SPeter Zijlstra if (unlikely(in_atomic() || lockdep_depth(current) > 0)) { 2217d5abe669SPeter Zijlstra printk(KERN_ERR "BUG: workqueue leaked lock or atomic: " 2218d5abe669SPeter Zijlstra "%s/0x%08x/%d\n", 2219a62428c0STejun Heo current->comm, preempt_count(), task_pid_nr(current)); 2220d5abe669SPeter Zijlstra printk(KERN_ERR " last function: "); 2221d5abe669SPeter Zijlstra print_symbol("%s\n", (unsigned long)f); 2222d5abe669SPeter Zijlstra debug_show_held_locks(current); 2223d5abe669SPeter Zijlstra dump_stack(); 2224d5abe669SPeter Zijlstra } 2225d5abe669SPeter Zijlstra 22268b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 2227a62428c0STejun Heo 2228fb0e7bebSTejun Heo /* clear cpu intensive status */ 2229fb0e7bebSTejun Heo if (unlikely(cpu_intensive)) 2230fb0e7bebSTejun Heo worker_clr_flags(worker, WORKER_CPU_INTENSIVE); 2231fb0e7bebSTejun Heo 2232a62428c0STejun Heo /* we're done with it, release */ 2233c8e55f36STejun Heo hlist_del_init(&worker->hentry); 2234c34056a3STejun Heo worker->current_work = NULL; 22358cca0eeaSTejun Heo worker->current_cwq = NULL; 22368a2e8e5dSTejun Heo cwq_dec_nr_in_flight(cwq, work_color, false); 22371da177e4SLinus Torvalds } 22381da177e4SLinus Torvalds 2239affee4b2STejun Heo /** 2240affee4b2STejun Heo * process_scheduled_works - process scheduled works 2241affee4b2STejun Heo * @worker: self 2242affee4b2STejun Heo * 2243affee4b2STejun Heo * Process all scheduled works. Please note that the scheduled list 2244affee4b2STejun Heo * may change while processing a work, so this function repeatedly 2245affee4b2STejun Heo * fetches a work from the top and executes it. 2246affee4b2STejun Heo * 2247affee4b2STejun Heo * CONTEXT: 22488b03ae3cSTejun Heo * spin_lock_irq(gcwq->lock) which may be released and regrabbed 2249affee4b2STejun Heo * multiple times. 2250affee4b2STejun Heo */ 2251affee4b2STejun Heo static void process_scheduled_works(struct worker *worker) 22521da177e4SLinus Torvalds { 2253affee4b2STejun Heo while (!list_empty(&worker->scheduled)) { 2254affee4b2STejun Heo struct work_struct *work = list_first_entry(&worker->scheduled, 2255a62428c0STejun Heo struct work_struct, entry); 2256c34056a3STejun Heo process_one_work(worker, work); 2257a62428c0STejun Heo } 22581da177e4SLinus Torvalds } 22591da177e4SLinus Torvalds 22604690c4abSTejun Heo /** 22614690c4abSTejun Heo * worker_thread - the worker thread function 2262c34056a3STejun Heo * @__worker: self 22634690c4abSTejun Heo * 2264e22bee78STejun Heo * The gcwq worker thread function. There's a single dynamic pool of 2265e22bee78STejun Heo * these per each cpu. These workers process all works regardless of 2266e22bee78STejun Heo * their specific target workqueue. The only exception is works which 2267e22bee78STejun Heo * belong to workqueues with a rescuer which will be explained in 2268e22bee78STejun Heo * rescuer_thread(). 22694690c4abSTejun Heo */ 2270c34056a3STejun Heo static int worker_thread(void *__worker) 22711da177e4SLinus Torvalds { 2272c34056a3STejun Heo struct worker *worker = __worker; 2273bd7bdd43STejun Heo struct worker_pool *pool = worker->pool; 2274bd7bdd43STejun Heo struct global_cwq *gcwq = pool->gcwq; 22751da177e4SLinus Torvalds 2276e22bee78STejun Heo /* tell the scheduler that this is a workqueue worker */ 2277e22bee78STejun Heo worker->task->flags |= PF_WQ_WORKER; 2278c8e55f36STejun Heo woke_up: 22798b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 2280affee4b2STejun Heo 228125511a47STejun Heo /* 228225511a47STejun Heo * DIE can be set only while idle and REBIND set while busy has 228325511a47STejun Heo * @worker->rebind_work scheduled. Checking here is enough. 228425511a47STejun Heo */ 228525511a47STejun Heo if (unlikely(worker->flags & (WORKER_REBIND | WORKER_DIE))) { 2286c8e55f36STejun Heo spin_unlock_irq(&gcwq->lock); 228725511a47STejun Heo 228825511a47STejun Heo if (worker->flags & WORKER_DIE) { 2289e22bee78STejun Heo worker->task->flags &= ~PF_WQ_WORKER; 2290c8e55f36STejun Heo return 0; 2291c8e55f36STejun Heo } 2292c8e55f36STejun Heo 229325511a47STejun Heo idle_worker_rebind(worker); 229425511a47STejun Heo goto woke_up; 229525511a47STejun Heo } 229625511a47STejun Heo 2297c8e55f36STejun Heo worker_leave_idle(worker); 2298db7bccf4STejun Heo recheck: 2299e22bee78STejun Heo /* no more worker necessary? */ 230063d95a91STejun Heo if (!need_more_worker(pool)) 2301e22bee78STejun Heo goto sleep; 2302e22bee78STejun Heo 2303e22bee78STejun Heo /* do we need to manage? */ 230463d95a91STejun Heo if (unlikely(!may_start_working(pool)) && manage_workers(worker)) 2305e22bee78STejun Heo goto recheck; 2306e22bee78STejun Heo 2307c8e55f36STejun Heo /* 2308c8e55f36STejun Heo * ->scheduled list can only be filled while a worker is 2309c8e55f36STejun Heo * preparing to process a work or actually processing it. 2310c8e55f36STejun Heo * Make sure nobody diddled with it while I was sleeping. 2311c8e55f36STejun Heo */ 2312c8e55f36STejun Heo BUG_ON(!list_empty(&worker->scheduled)); 2313c8e55f36STejun Heo 2314e22bee78STejun Heo /* 2315e22bee78STejun Heo * When control reaches this point, we're guaranteed to have 2316e22bee78STejun Heo * at least one idle worker or that someone else has already 2317e22bee78STejun Heo * assumed the manager role. 2318e22bee78STejun Heo */ 2319e22bee78STejun Heo worker_clr_flags(worker, WORKER_PREP); 2320e22bee78STejun Heo 2321e22bee78STejun Heo do { 2322affee4b2STejun Heo struct work_struct *work = 2323bd7bdd43STejun Heo list_first_entry(&pool->worklist, 2324affee4b2STejun Heo struct work_struct, entry); 2325affee4b2STejun Heo 2326c8e55f36STejun Heo if (likely(!(*work_data_bits(work) & WORK_STRUCT_LINKED))) { 2327affee4b2STejun Heo /* optimization path, not strictly necessary */ 2328affee4b2STejun Heo process_one_work(worker, work); 2329affee4b2STejun Heo if (unlikely(!list_empty(&worker->scheduled))) 2330affee4b2STejun Heo process_scheduled_works(worker); 2331affee4b2STejun Heo } else { 2332c8e55f36STejun Heo move_linked_works(work, &worker->scheduled, NULL); 2333affee4b2STejun Heo process_scheduled_works(worker); 2334affee4b2STejun Heo } 233563d95a91STejun Heo } while (keep_working(pool)); 2336affee4b2STejun Heo 2337e22bee78STejun Heo worker_set_flags(worker, WORKER_PREP, false); 2338d313dd85STejun Heo sleep: 233963d95a91STejun Heo if (unlikely(need_to_manage_workers(pool)) && manage_workers(worker)) 2340e22bee78STejun Heo goto recheck; 2341d313dd85STejun Heo 2342c8e55f36STejun Heo /* 2343e22bee78STejun Heo * gcwq->lock is held and there's no work to process and no 2344e22bee78STejun Heo * need to manage, sleep. Workers are woken up only while 2345e22bee78STejun Heo * holding gcwq->lock or from local cpu, so setting the 2346e22bee78STejun Heo * current state before releasing gcwq->lock is enough to 2347e22bee78STejun Heo * prevent losing any event. 2348c8e55f36STejun Heo */ 2349c8e55f36STejun Heo worker_enter_idle(worker); 2350c8e55f36STejun Heo __set_current_state(TASK_INTERRUPTIBLE); 23518b03ae3cSTejun Heo spin_unlock_irq(&gcwq->lock); 23521da177e4SLinus Torvalds schedule(); 2353c8e55f36STejun Heo goto woke_up; 23541da177e4SLinus Torvalds } 23551da177e4SLinus Torvalds 2356e22bee78STejun Heo /** 2357e22bee78STejun Heo * rescuer_thread - the rescuer thread function 2358e22bee78STejun Heo * @__wq: the associated workqueue 2359e22bee78STejun Heo * 2360e22bee78STejun Heo * Workqueue rescuer thread function. There's one rescuer for each 2361e22bee78STejun Heo * workqueue which has WQ_RESCUER set. 2362e22bee78STejun Heo * 2363e22bee78STejun Heo * Regular work processing on a gcwq may block trying to create a new 2364e22bee78STejun Heo * worker which uses GFP_KERNEL allocation which has slight chance of 2365e22bee78STejun Heo * developing into deadlock if some works currently on the same queue 2366e22bee78STejun Heo * need to be processed to satisfy the GFP_KERNEL allocation. This is 2367e22bee78STejun Heo * the problem rescuer solves. 2368e22bee78STejun Heo * 2369e22bee78STejun Heo * When such condition is possible, the gcwq summons rescuers of all 2370e22bee78STejun Heo * workqueues which have works queued on the gcwq and let them process 2371e22bee78STejun Heo * those works so that forward progress can be guaranteed. 2372e22bee78STejun Heo * 2373e22bee78STejun Heo * This should happen rarely. 2374e22bee78STejun Heo */ 2375e22bee78STejun Heo static int rescuer_thread(void *__wq) 2376e22bee78STejun Heo { 2377e22bee78STejun Heo struct workqueue_struct *wq = __wq; 2378e22bee78STejun Heo struct worker *rescuer = wq->rescuer; 2379e22bee78STejun Heo struct list_head *scheduled = &rescuer->scheduled; 2380f3421797STejun Heo bool is_unbound = wq->flags & WQ_UNBOUND; 2381e22bee78STejun Heo unsigned int cpu; 2382e22bee78STejun Heo 2383e22bee78STejun Heo set_user_nice(current, RESCUER_NICE_LEVEL); 2384e22bee78STejun Heo repeat: 2385e22bee78STejun Heo set_current_state(TASK_INTERRUPTIBLE); 23861da177e4SLinus Torvalds 23871da177e4SLinus Torvalds if (kthread_should_stop()) 2388e22bee78STejun Heo return 0; 23891da177e4SLinus Torvalds 2390f3421797STejun Heo /* 2391f3421797STejun Heo * See whether any cpu is asking for help. Unbounded 2392f3421797STejun Heo * workqueues use cpu 0 in mayday_mask for CPU_UNBOUND. 2393f3421797STejun Heo */ 2394f2e005aaSTejun Heo for_each_mayday_cpu(cpu, wq->mayday_mask) { 2395f3421797STejun Heo unsigned int tcpu = is_unbound ? WORK_CPU_UNBOUND : cpu; 2396f3421797STejun Heo struct cpu_workqueue_struct *cwq = get_cwq(tcpu, wq); 2397bd7bdd43STejun Heo struct worker_pool *pool = cwq->pool; 2398bd7bdd43STejun Heo struct global_cwq *gcwq = pool->gcwq; 2399e22bee78STejun Heo struct work_struct *work, *n; 2400e22bee78STejun Heo 2401e22bee78STejun Heo __set_current_state(TASK_RUNNING); 2402f2e005aaSTejun Heo mayday_clear_cpu(cpu, wq->mayday_mask); 2403e22bee78STejun Heo 2404e22bee78STejun Heo /* migrate to the target cpu if possible */ 2405bd7bdd43STejun Heo rescuer->pool = pool; 2406e22bee78STejun Heo worker_maybe_bind_and_lock(rescuer); 2407e22bee78STejun Heo 2408e22bee78STejun Heo /* 2409e22bee78STejun Heo * Slurp in all works issued via this workqueue and 2410e22bee78STejun Heo * process'em. 2411e22bee78STejun Heo */ 2412e22bee78STejun Heo BUG_ON(!list_empty(&rescuer->scheduled)); 2413bd7bdd43STejun Heo list_for_each_entry_safe(work, n, &pool->worklist, entry) 2414e22bee78STejun Heo if (get_work_cwq(work) == cwq) 2415e22bee78STejun Heo move_linked_works(work, scheduled, &n); 2416e22bee78STejun Heo 2417e22bee78STejun Heo process_scheduled_works(rescuer); 24187576958aSTejun Heo 24197576958aSTejun Heo /* 24207576958aSTejun Heo * Leave this gcwq. If keep_working() is %true, notify a 24217576958aSTejun Heo * regular worker; otherwise, we end up with 0 concurrency 24227576958aSTejun Heo * and stalling the execution. 24237576958aSTejun Heo */ 242463d95a91STejun Heo if (keep_working(pool)) 242563d95a91STejun Heo wake_up_worker(pool); 24267576958aSTejun Heo 2427e22bee78STejun Heo spin_unlock_irq(&gcwq->lock); 24281da177e4SLinus Torvalds } 24291da177e4SLinus Torvalds 2430e22bee78STejun Heo schedule(); 2431e22bee78STejun Heo goto repeat; 24321da177e4SLinus Torvalds } 24331da177e4SLinus Torvalds 2434fc2e4d70SOleg Nesterov struct wq_barrier { 2435fc2e4d70SOleg Nesterov struct work_struct work; 2436fc2e4d70SOleg Nesterov struct completion done; 2437fc2e4d70SOleg Nesterov }; 2438fc2e4d70SOleg Nesterov 2439fc2e4d70SOleg Nesterov static void wq_barrier_func(struct work_struct *work) 2440fc2e4d70SOleg Nesterov { 2441fc2e4d70SOleg Nesterov struct wq_barrier *barr = container_of(work, struct wq_barrier, work); 2442fc2e4d70SOleg Nesterov complete(&barr->done); 2443fc2e4d70SOleg Nesterov } 2444fc2e4d70SOleg Nesterov 24454690c4abSTejun Heo /** 24464690c4abSTejun Heo * insert_wq_barrier - insert a barrier work 24474690c4abSTejun Heo * @cwq: cwq to insert barrier into 24484690c4abSTejun Heo * @barr: wq_barrier to insert 2449affee4b2STejun Heo * @target: target work to attach @barr to 2450affee4b2STejun Heo * @worker: worker currently executing @target, NULL if @target is not executing 24514690c4abSTejun Heo * 2452affee4b2STejun Heo * @barr is linked to @target such that @barr is completed only after 2453affee4b2STejun Heo * @target finishes execution. Please note that the ordering 2454affee4b2STejun Heo * guarantee is observed only with respect to @target and on the local 2455affee4b2STejun Heo * cpu. 2456affee4b2STejun Heo * 2457affee4b2STejun Heo * Currently, a queued barrier can't be canceled. This is because 2458affee4b2STejun Heo * try_to_grab_pending() can't determine whether the work to be 2459affee4b2STejun Heo * grabbed is at the head of the queue and thus can't clear LINKED 2460affee4b2STejun Heo * flag of the previous work while there must be a valid next work 2461affee4b2STejun Heo * after a work with LINKED flag set. 2462affee4b2STejun Heo * 2463affee4b2STejun Heo * Note that when @worker is non-NULL, @target may be modified 2464affee4b2STejun Heo * underneath us, so we can't reliably determine cwq from @target. 24654690c4abSTejun Heo * 24664690c4abSTejun Heo * CONTEXT: 24678b03ae3cSTejun Heo * spin_lock_irq(gcwq->lock). 24684690c4abSTejun Heo */ 246983c22520SOleg Nesterov static void insert_wq_barrier(struct cpu_workqueue_struct *cwq, 2470affee4b2STejun Heo struct wq_barrier *barr, 2471affee4b2STejun Heo struct work_struct *target, struct worker *worker) 2472fc2e4d70SOleg Nesterov { 2473affee4b2STejun Heo struct list_head *head; 2474affee4b2STejun Heo unsigned int linked = 0; 2475affee4b2STejun Heo 2476dc186ad7SThomas Gleixner /* 24778b03ae3cSTejun Heo * debugobject calls are safe here even with gcwq->lock locked 2478dc186ad7SThomas Gleixner * as we know for sure that this will not trigger any of the 2479dc186ad7SThomas Gleixner * checks and call back into the fixup functions where we 2480dc186ad7SThomas Gleixner * might deadlock. 2481dc186ad7SThomas Gleixner */ 2482ca1cab37SAndrew Morton INIT_WORK_ONSTACK(&barr->work, wq_barrier_func); 248322df02bbSTejun Heo __set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&barr->work)); 2484fc2e4d70SOleg Nesterov init_completion(&barr->done); 248583c22520SOleg Nesterov 2486affee4b2STejun Heo /* 2487affee4b2STejun Heo * If @target is currently being executed, schedule the 2488affee4b2STejun Heo * barrier to the worker; otherwise, put it after @target. 2489affee4b2STejun Heo */ 2490affee4b2STejun Heo if (worker) 2491affee4b2STejun Heo head = worker->scheduled.next; 2492affee4b2STejun Heo else { 2493affee4b2STejun Heo unsigned long *bits = work_data_bits(target); 2494affee4b2STejun Heo 2495affee4b2STejun Heo head = target->entry.next; 2496affee4b2STejun Heo /* there can already be other linked works, inherit and set */ 2497affee4b2STejun Heo linked = *bits & WORK_STRUCT_LINKED; 2498affee4b2STejun Heo __set_bit(WORK_STRUCT_LINKED_BIT, bits); 2499affee4b2STejun Heo } 2500affee4b2STejun Heo 2501dc186ad7SThomas Gleixner debug_work_activate(&barr->work); 2502affee4b2STejun Heo insert_work(cwq, &barr->work, head, 2503affee4b2STejun Heo work_color_to_flags(WORK_NO_COLOR) | linked); 2504fc2e4d70SOleg Nesterov } 2505fc2e4d70SOleg Nesterov 250673f53c4aSTejun Heo /** 250773f53c4aSTejun Heo * flush_workqueue_prep_cwqs - prepare cwqs for workqueue flushing 250873f53c4aSTejun Heo * @wq: workqueue being flushed 250973f53c4aSTejun Heo * @flush_color: new flush color, < 0 for no-op 251073f53c4aSTejun Heo * @work_color: new work color, < 0 for no-op 251173f53c4aSTejun Heo * 251273f53c4aSTejun Heo * Prepare cwqs for workqueue flushing. 251373f53c4aSTejun Heo * 251473f53c4aSTejun Heo * If @flush_color is non-negative, flush_color on all cwqs should be 251573f53c4aSTejun Heo * -1. If no cwq has in-flight commands at the specified color, all 251673f53c4aSTejun Heo * cwq->flush_color's stay at -1 and %false is returned. If any cwq 251773f53c4aSTejun Heo * has in flight commands, its cwq->flush_color is set to 251873f53c4aSTejun Heo * @flush_color, @wq->nr_cwqs_to_flush is updated accordingly, cwq 251973f53c4aSTejun Heo * wakeup logic is armed and %true is returned. 252073f53c4aSTejun Heo * 252173f53c4aSTejun Heo * The caller should have initialized @wq->first_flusher prior to 252273f53c4aSTejun Heo * calling this function with non-negative @flush_color. If 252373f53c4aSTejun Heo * @flush_color is negative, no flush color update is done and %false 252473f53c4aSTejun Heo * is returned. 252573f53c4aSTejun Heo * 252673f53c4aSTejun Heo * If @work_color is non-negative, all cwqs should have the same 252773f53c4aSTejun Heo * work_color which is previous to @work_color and all will be 252873f53c4aSTejun Heo * advanced to @work_color. 252973f53c4aSTejun Heo * 253073f53c4aSTejun Heo * CONTEXT: 253173f53c4aSTejun Heo * mutex_lock(wq->flush_mutex). 253273f53c4aSTejun Heo * 253373f53c4aSTejun Heo * RETURNS: 253473f53c4aSTejun Heo * %true if @flush_color >= 0 and there's something to flush. %false 253573f53c4aSTejun Heo * otherwise. 253673f53c4aSTejun Heo */ 253773f53c4aSTejun Heo static bool flush_workqueue_prep_cwqs(struct workqueue_struct *wq, 253873f53c4aSTejun Heo int flush_color, int work_color) 25391da177e4SLinus Torvalds { 254073f53c4aSTejun Heo bool wait = false; 254173f53c4aSTejun Heo unsigned int cpu; 25421da177e4SLinus Torvalds 254373f53c4aSTejun Heo if (flush_color >= 0) { 254473f53c4aSTejun Heo BUG_ON(atomic_read(&wq->nr_cwqs_to_flush)); 254573f53c4aSTejun Heo atomic_set(&wq->nr_cwqs_to_flush, 1); 2546dc186ad7SThomas Gleixner } 254714441960SOleg Nesterov 2548f3421797STejun Heo for_each_cwq_cpu(cpu, wq) { 254973f53c4aSTejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 2550bd7bdd43STejun Heo struct global_cwq *gcwq = cwq->pool->gcwq; 25511da177e4SLinus Torvalds 25528b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 255373f53c4aSTejun Heo 255473f53c4aSTejun Heo if (flush_color >= 0) { 255573f53c4aSTejun Heo BUG_ON(cwq->flush_color != -1); 255673f53c4aSTejun Heo 255773f53c4aSTejun Heo if (cwq->nr_in_flight[flush_color]) { 255873f53c4aSTejun Heo cwq->flush_color = flush_color; 255973f53c4aSTejun Heo atomic_inc(&wq->nr_cwqs_to_flush); 256073f53c4aSTejun Heo wait = true; 25611da177e4SLinus Torvalds } 256273f53c4aSTejun Heo } 256373f53c4aSTejun Heo 256473f53c4aSTejun Heo if (work_color >= 0) { 256573f53c4aSTejun Heo BUG_ON(work_color != work_next_color(cwq->work_color)); 256673f53c4aSTejun Heo cwq->work_color = work_color; 256773f53c4aSTejun Heo } 256873f53c4aSTejun Heo 25698b03ae3cSTejun Heo spin_unlock_irq(&gcwq->lock); 25701da177e4SLinus Torvalds } 25711da177e4SLinus Torvalds 257273f53c4aSTejun Heo if (flush_color >= 0 && atomic_dec_and_test(&wq->nr_cwqs_to_flush)) 257373f53c4aSTejun Heo complete(&wq->first_flusher->done); 257473f53c4aSTejun Heo 257573f53c4aSTejun Heo return wait; 257683c22520SOleg Nesterov } 25771da177e4SLinus Torvalds 25780fcb78c2SRolf Eike Beer /** 25791da177e4SLinus Torvalds * flush_workqueue - ensure that any scheduled work has run to completion. 25800fcb78c2SRolf Eike Beer * @wq: workqueue to flush 25811da177e4SLinus Torvalds * 25821da177e4SLinus Torvalds * Forces execution of the workqueue and blocks until its completion. 25831da177e4SLinus Torvalds * This is typically used in driver shutdown handlers. 25841da177e4SLinus Torvalds * 2585fc2e4d70SOleg Nesterov * We sleep until all works which were queued on entry have been handled, 2586fc2e4d70SOleg Nesterov * but we are not livelocked by new incoming ones. 25871da177e4SLinus Torvalds */ 25887ad5b3a5SHarvey Harrison void flush_workqueue(struct workqueue_struct *wq) 25891da177e4SLinus Torvalds { 259073f53c4aSTejun Heo struct wq_flusher this_flusher = { 259173f53c4aSTejun Heo .list = LIST_HEAD_INIT(this_flusher.list), 259273f53c4aSTejun Heo .flush_color = -1, 259373f53c4aSTejun Heo .done = COMPLETION_INITIALIZER_ONSTACK(this_flusher.done), 259473f53c4aSTejun Heo }; 259573f53c4aSTejun Heo int next_color; 2596b1f4ec17SOleg Nesterov 25973295f0efSIngo Molnar lock_map_acquire(&wq->lockdep_map); 25983295f0efSIngo Molnar lock_map_release(&wq->lockdep_map); 259973f53c4aSTejun Heo 260073f53c4aSTejun Heo mutex_lock(&wq->flush_mutex); 260173f53c4aSTejun Heo 260273f53c4aSTejun Heo /* 260373f53c4aSTejun Heo * Start-to-wait phase 260473f53c4aSTejun Heo */ 260573f53c4aSTejun Heo next_color = work_next_color(wq->work_color); 260673f53c4aSTejun Heo 260773f53c4aSTejun Heo if (next_color != wq->flush_color) { 260873f53c4aSTejun Heo /* 260973f53c4aSTejun Heo * Color space is not full. The current work_color 261073f53c4aSTejun Heo * becomes our flush_color and work_color is advanced 261173f53c4aSTejun Heo * by one. 261273f53c4aSTejun Heo */ 261373f53c4aSTejun Heo BUG_ON(!list_empty(&wq->flusher_overflow)); 261473f53c4aSTejun Heo this_flusher.flush_color = wq->work_color; 261573f53c4aSTejun Heo wq->work_color = next_color; 261673f53c4aSTejun Heo 261773f53c4aSTejun Heo if (!wq->first_flusher) { 261873f53c4aSTejun Heo /* no flush in progress, become the first flusher */ 261973f53c4aSTejun Heo BUG_ON(wq->flush_color != this_flusher.flush_color); 262073f53c4aSTejun Heo 262173f53c4aSTejun Heo wq->first_flusher = &this_flusher; 262273f53c4aSTejun Heo 262373f53c4aSTejun Heo if (!flush_workqueue_prep_cwqs(wq, wq->flush_color, 262473f53c4aSTejun Heo wq->work_color)) { 262573f53c4aSTejun Heo /* nothing to flush, done */ 262673f53c4aSTejun Heo wq->flush_color = next_color; 262773f53c4aSTejun Heo wq->first_flusher = NULL; 262873f53c4aSTejun Heo goto out_unlock; 262973f53c4aSTejun Heo } 263073f53c4aSTejun Heo } else { 263173f53c4aSTejun Heo /* wait in queue */ 263273f53c4aSTejun Heo BUG_ON(wq->flush_color == this_flusher.flush_color); 263373f53c4aSTejun Heo list_add_tail(&this_flusher.list, &wq->flusher_queue); 263473f53c4aSTejun Heo flush_workqueue_prep_cwqs(wq, -1, wq->work_color); 263573f53c4aSTejun Heo } 263673f53c4aSTejun Heo } else { 263773f53c4aSTejun Heo /* 263873f53c4aSTejun Heo * Oops, color space is full, wait on overflow queue. 263973f53c4aSTejun Heo * The next flush completion will assign us 264073f53c4aSTejun Heo * flush_color and transfer to flusher_queue. 264173f53c4aSTejun Heo */ 264273f53c4aSTejun Heo list_add_tail(&this_flusher.list, &wq->flusher_overflow); 264373f53c4aSTejun Heo } 264473f53c4aSTejun Heo 264573f53c4aSTejun Heo mutex_unlock(&wq->flush_mutex); 264673f53c4aSTejun Heo 264773f53c4aSTejun Heo wait_for_completion(&this_flusher.done); 264873f53c4aSTejun Heo 264973f53c4aSTejun Heo /* 265073f53c4aSTejun Heo * Wake-up-and-cascade phase 265173f53c4aSTejun Heo * 265273f53c4aSTejun Heo * First flushers are responsible for cascading flushes and 265373f53c4aSTejun Heo * handling overflow. Non-first flushers can simply return. 265473f53c4aSTejun Heo */ 265573f53c4aSTejun Heo if (wq->first_flusher != &this_flusher) 265673f53c4aSTejun Heo return; 265773f53c4aSTejun Heo 265873f53c4aSTejun Heo mutex_lock(&wq->flush_mutex); 265973f53c4aSTejun Heo 26604ce48b37STejun Heo /* we might have raced, check again with mutex held */ 26614ce48b37STejun Heo if (wq->first_flusher != &this_flusher) 26624ce48b37STejun Heo goto out_unlock; 26634ce48b37STejun Heo 266473f53c4aSTejun Heo wq->first_flusher = NULL; 266573f53c4aSTejun Heo 266673f53c4aSTejun Heo BUG_ON(!list_empty(&this_flusher.list)); 266773f53c4aSTejun Heo BUG_ON(wq->flush_color != this_flusher.flush_color); 266873f53c4aSTejun Heo 266973f53c4aSTejun Heo while (true) { 267073f53c4aSTejun Heo struct wq_flusher *next, *tmp; 267173f53c4aSTejun Heo 267273f53c4aSTejun Heo /* complete all the flushers sharing the current flush color */ 267373f53c4aSTejun Heo list_for_each_entry_safe(next, tmp, &wq->flusher_queue, list) { 267473f53c4aSTejun Heo if (next->flush_color != wq->flush_color) 267573f53c4aSTejun Heo break; 267673f53c4aSTejun Heo list_del_init(&next->list); 267773f53c4aSTejun Heo complete(&next->done); 267873f53c4aSTejun Heo } 267973f53c4aSTejun Heo 268073f53c4aSTejun Heo BUG_ON(!list_empty(&wq->flusher_overflow) && 268173f53c4aSTejun Heo wq->flush_color != work_next_color(wq->work_color)); 268273f53c4aSTejun Heo 268373f53c4aSTejun Heo /* this flush_color is finished, advance by one */ 268473f53c4aSTejun Heo wq->flush_color = work_next_color(wq->flush_color); 268573f53c4aSTejun Heo 268673f53c4aSTejun Heo /* one color has been freed, handle overflow queue */ 268773f53c4aSTejun Heo if (!list_empty(&wq->flusher_overflow)) { 268873f53c4aSTejun Heo /* 268973f53c4aSTejun Heo * Assign the same color to all overflowed 269073f53c4aSTejun Heo * flushers, advance work_color and append to 269173f53c4aSTejun Heo * flusher_queue. This is the start-to-wait 269273f53c4aSTejun Heo * phase for these overflowed flushers. 269373f53c4aSTejun Heo */ 269473f53c4aSTejun Heo list_for_each_entry(tmp, &wq->flusher_overflow, list) 269573f53c4aSTejun Heo tmp->flush_color = wq->work_color; 269673f53c4aSTejun Heo 269773f53c4aSTejun Heo wq->work_color = work_next_color(wq->work_color); 269873f53c4aSTejun Heo 269973f53c4aSTejun Heo list_splice_tail_init(&wq->flusher_overflow, 270073f53c4aSTejun Heo &wq->flusher_queue); 270173f53c4aSTejun Heo flush_workqueue_prep_cwqs(wq, -1, wq->work_color); 270273f53c4aSTejun Heo } 270373f53c4aSTejun Heo 270473f53c4aSTejun Heo if (list_empty(&wq->flusher_queue)) { 270573f53c4aSTejun Heo BUG_ON(wq->flush_color != wq->work_color); 270673f53c4aSTejun Heo break; 270773f53c4aSTejun Heo } 270873f53c4aSTejun Heo 270973f53c4aSTejun Heo /* 271073f53c4aSTejun Heo * Need to flush more colors. Make the next flusher 271173f53c4aSTejun Heo * the new first flusher and arm cwqs. 271273f53c4aSTejun Heo */ 271373f53c4aSTejun Heo BUG_ON(wq->flush_color == wq->work_color); 271473f53c4aSTejun Heo BUG_ON(wq->flush_color != next->flush_color); 271573f53c4aSTejun Heo 271673f53c4aSTejun Heo list_del_init(&next->list); 271773f53c4aSTejun Heo wq->first_flusher = next; 271873f53c4aSTejun Heo 271973f53c4aSTejun Heo if (flush_workqueue_prep_cwqs(wq, wq->flush_color, -1)) 272073f53c4aSTejun Heo break; 272173f53c4aSTejun Heo 272273f53c4aSTejun Heo /* 272373f53c4aSTejun Heo * Meh... this color is already done, clear first 272473f53c4aSTejun Heo * flusher and repeat cascading. 272573f53c4aSTejun Heo */ 272673f53c4aSTejun Heo wq->first_flusher = NULL; 272773f53c4aSTejun Heo } 272873f53c4aSTejun Heo 272973f53c4aSTejun Heo out_unlock: 273073f53c4aSTejun Heo mutex_unlock(&wq->flush_mutex); 27311da177e4SLinus Torvalds } 2732ae90dd5dSDave Jones EXPORT_SYMBOL_GPL(flush_workqueue); 27331da177e4SLinus Torvalds 27349c5a2ba7STejun Heo /** 27359c5a2ba7STejun Heo * drain_workqueue - drain a workqueue 27369c5a2ba7STejun Heo * @wq: workqueue to drain 27379c5a2ba7STejun Heo * 27389c5a2ba7STejun Heo * Wait until the workqueue becomes empty. While draining is in progress, 27399c5a2ba7STejun Heo * only chain queueing is allowed. IOW, only currently pending or running 27409c5a2ba7STejun Heo * work items on @wq can queue further work items on it. @wq is flushed 27419c5a2ba7STejun Heo * repeatedly until it becomes empty. The number of flushing is detemined 27429c5a2ba7STejun Heo * by the depth of chaining and should be relatively short. Whine if it 27439c5a2ba7STejun Heo * takes too long. 27449c5a2ba7STejun Heo */ 27459c5a2ba7STejun Heo void drain_workqueue(struct workqueue_struct *wq) 27469c5a2ba7STejun Heo { 27479c5a2ba7STejun Heo unsigned int flush_cnt = 0; 27489c5a2ba7STejun Heo unsigned int cpu; 27499c5a2ba7STejun Heo 27509c5a2ba7STejun Heo /* 27519c5a2ba7STejun Heo * __queue_work() needs to test whether there are drainers, is much 27529c5a2ba7STejun Heo * hotter than drain_workqueue() and already looks at @wq->flags. 27539c5a2ba7STejun Heo * Use WQ_DRAINING so that queue doesn't have to check nr_drainers. 27549c5a2ba7STejun Heo */ 27559c5a2ba7STejun Heo spin_lock(&workqueue_lock); 27569c5a2ba7STejun Heo if (!wq->nr_drainers++) 27579c5a2ba7STejun Heo wq->flags |= WQ_DRAINING; 27589c5a2ba7STejun Heo spin_unlock(&workqueue_lock); 27599c5a2ba7STejun Heo reflush: 27609c5a2ba7STejun Heo flush_workqueue(wq); 27619c5a2ba7STejun Heo 27629c5a2ba7STejun Heo for_each_cwq_cpu(cpu, wq) { 27639c5a2ba7STejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 2764fa2563e4SThomas Tuttle bool drained; 27659c5a2ba7STejun Heo 2766bd7bdd43STejun Heo spin_lock_irq(&cwq->pool->gcwq->lock); 2767fa2563e4SThomas Tuttle drained = !cwq->nr_active && list_empty(&cwq->delayed_works); 2768bd7bdd43STejun Heo spin_unlock_irq(&cwq->pool->gcwq->lock); 2769fa2563e4SThomas Tuttle 2770fa2563e4SThomas Tuttle if (drained) 27719c5a2ba7STejun Heo continue; 27729c5a2ba7STejun Heo 27739c5a2ba7STejun Heo if (++flush_cnt == 10 || 27749c5a2ba7STejun Heo (flush_cnt % 100 == 0 && flush_cnt <= 1000)) 27759c5a2ba7STejun Heo pr_warning("workqueue %s: flush on destruction isn't complete after %u tries\n", 27769c5a2ba7STejun Heo wq->name, flush_cnt); 27779c5a2ba7STejun Heo goto reflush; 27789c5a2ba7STejun Heo } 27799c5a2ba7STejun Heo 27809c5a2ba7STejun Heo spin_lock(&workqueue_lock); 27819c5a2ba7STejun Heo if (!--wq->nr_drainers) 27829c5a2ba7STejun Heo wq->flags &= ~WQ_DRAINING; 27839c5a2ba7STejun Heo spin_unlock(&workqueue_lock); 27849c5a2ba7STejun Heo } 27859c5a2ba7STejun Heo EXPORT_SYMBOL_GPL(drain_workqueue); 27869c5a2ba7STejun Heo 2787baf59022STejun Heo static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr, 2788baf59022STejun Heo bool wait_executing) 2789baf59022STejun Heo { 2790baf59022STejun Heo struct worker *worker = NULL; 2791baf59022STejun Heo struct global_cwq *gcwq; 2792baf59022STejun Heo struct cpu_workqueue_struct *cwq; 2793baf59022STejun Heo 2794baf59022STejun Heo might_sleep(); 2795baf59022STejun Heo gcwq = get_work_gcwq(work); 2796baf59022STejun Heo if (!gcwq) 2797baf59022STejun Heo return false; 2798baf59022STejun Heo 2799baf59022STejun Heo spin_lock_irq(&gcwq->lock); 2800baf59022STejun Heo if (!list_empty(&work->entry)) { 2801baf59022STejun Heo /* 2802baf59022STejun Heo * See the comment near try_to_grab_pending()->smp_rmb(). 2803baf59022STejun Heo * If it was re-queued to a different gcwq under us, we 2804baf59022STejun Heo * are not going to wait. 2805baf59022STejun Heo */ 2806baf59022STejun Heo smp_rmb(); 2807baf59022STejun Heo cwq = get_work_cwq(work); 2808bd7bdd43STejun Heo if (unlikely(!cwq || gcwq != cwq->pool->gcwq)) 2809baf59022STejun Heo goto already_gone; 2810baf59022STejun Heo } else if (wait_executing) { 2811baf59022STejun Heo worker = find_worker_executing_work(gcwq, work); 2812baf59022STejun Heo if (!worker) 2813baf59022STejun Heo goto already_gone; 2814baf59022STejun Heo cwq = worker->current_cwq; 2815baf59022STejun Heo } else 2816baf59022STejun Heo goto already_gone; 2817baf59022STejun Heo 2818baf59022STejun Heo insert_wq_barrier(cwq, barr, work, worker); 2819baf59022STejun Heo spin_unlock_irq(&gcwq->lock); 2820baf59022STejun Heo 2821e159489bSTejun Heo /* 2822e159489bSTejun Heo * If @max_active is 1 or rescuer is in use, flushing another work 2823e159489bSTejun Heo * item on the same workqueue may lead to deadlock. Make sure the 2824e159489bSTejun Heo * flusher is not running on the same workqueue by verifying write 2825e159489bSTejun Heo * access. 2826e159489bSTejun Heo */ 2827e159489bSTejun Heo if (cwq->wq->saved_max_active == 1 || cwq->wq->flags & WQ_RESCUER) 2828baf59022STejun Heo lock_map_acquire(&cwq->wq->lockdep_map); 2829e159489bSTejun Heo else 2830e159489bSTejun Heo lock_map_acquire_read(&cwq->wq->lockdep_map); 2831baf59022STejun Heo lock_map_release(&cwq->wq->lockdep_map); 2832e159489bSTejun Heo 2833baf59022STejun Heo return true; 2834baf59022STejun Heo already_gone: 2835baf59022STejun Heo spin_unlock_irq(&gcwq->lock); 2836baf59022STejun Heo return false; 2837baf59022STejun Heo } 2838baf59022STejun Heo 2839db700897SOleg Nesterov /** 2840401a8d04STejun Heo * flush_work - wait for a work to finish executing the last queueing instance 2841401a8d04STejun Heo * @work: the work to flush 2842db700897SOleg Nesterov * 2843401a8d04STejun Heo * Wait until @work has finished execution. This function considers 2844401a8d04STejun Heo * only the last queueing instance of @work. If @work has been 2845401a8d04STejun Heo * enqueued across different CPUs on a non-reentrant workqueue or on 2846401a8d04STejun Heo * multiple workqueues, @work might still be executing on return on 2847401a8d04STejun Heo * some of the CPUs from earlier queueing. 2848a67da70dSOleg Nesterov * 2849401a8d04STejun Heo * If @work was queued only on a non-reentrant, ordered or unbound 2850401a8d04STejun Heo * workqueue, @work is guaranteed to be idle on return if it hasn't 2851401a8d04STejun Heo * been requeued since flush started. 2852401a8d04STejun Heo * 2853401a8d04STejun Heo * RETURNS: 2854401a8d04STejun Heo * %true if flush_work() waited for the work to finish execution, 2855401a8d04STejun Heo * %false if it was already idle. 2856db700897SOleg Nesterov */ 2857401a8d04STejun Heo bool flush_work(struct work_struct *work) 2858db700897SOleg Nesterov { 2859db700897SOleg Nesterov struct wq_barrier barr; 2860db700897SOleg Nesterov 28610976dfc1SStephen Boyd lock_map_acquire(&work->lockdep_map); 28620976dfc1SStephen Boyd lock_map_release(&work->lockdep_map); 28630976dfc1SStephen Boyd 2864baf59022STejun Heo if (start_flush_work(work, &barr, true)) { 2865db700897SOleg Nesterov wait_for_completion(&barr.done); 2866dc186ad7SThomas Gleixner destroy_work_on_stack(&barr.work); 2867401a8d04STejun Heo return true; 2868baf59022STejun Heo } else 2869401a8d04STejun Heo return false; 2870db700897SOleg Nesterov } 2871db700897SOleg Nesterov EXPORT_SYMBOL_GPL(flush_work); 2872db700897SOleg Nesterov 2873401a8d04STejun Heo static bool wait_on_cpu_work(struct global_cwq *gcwq, struct work_struct *work) 2874401a8d04STejun Heo { 2875401a8d04STejun Heo struct wq_barrier barr; 2876401a8d04STejun Heo struct worker *worker; 2877401a8d04STejun Heo 2878401a8d04STejun Heo spin_lock_irq(&gcwq->lock); 2879401a8d04STejun Heo 2880401a8d04STejun Heo worker = find_worker_executing_work(gcwq, work); 2881401a8d04STejun Heo if (unlikely(worker)) 2882401a8d04STejun Heo insert_wq_barrier(worker->current_cwq, &barr, work, worker); 2883401a8d04STejun Heo 2884401a8d04STejun Heo spin_unlock_irq(&gcwq->lock); 2885401a8d04STejun Heo 2886401a8d04STejun Heo if (unlikely(worker)) { 2887401a8d04STejun Heo wait_for_completion(&barr.done); 2888401a8d04STejun Heo destroy_work_on_stack(&barr.work); 2889401a8d04STejun Heo return true; 2890401a8d04STejun Heo } else 2891401a8d04STejun Heo return false; 2892401a8d04STejun Heo } 2893401a8d04STejun Heo 2894401a8d04STejun Heo static bool wait_on_work(struct work_struct *work) 2895401a8d04STejun Heo { 2896401a8d04STejun Heo bool ret = false; 2897401a8d04STejun Heo int cpu; 2898401a8d04STejun Heo 2899401a8d04STejun Heo might_sleep(); 2900401a8d04STejun Heo 2901401a8d04STejun Heo lock_map_acquire(&work->lockdep_map); 2902401a8d04STejun Heo lock_map_release(&work->lockdep_map); 2903401a8d04STejun Heo 2904401a8d04STejun Heo for_each_gcwq_cpu(cpu) 2905401a8d04STejun Heo ret |= wait_on_cpu_work(get_gcwq(cpu), work); 2906401a8d04STejun Heo return ret; 2907401a8d04STejun Heo } 2908401a8d04STejun Heo 290909383498STejun Heo /** 291009383498STejun Heo * flush_work_sync - wait until a work has finished execution 291109383498STejun Heo * @work: the work to flush 291209383498STejun Heo * 291309383498STejun Heo * Wait until @work has finished execution. On return, it's 291409383498STejun Heo * guaranteed that all queueing instances of @work which happened 291509383498STejun Heo * before this function is called are finished. In other words, if 291609383498STejun Heo * @work hasn't been requeued since this function was called, @work is 291709383498STejun Heo * guaranteed to be idle on return. 291809383498STejun Heo * 291909383498STejun Heo * RETURNS: 292009383498STejun Heo * %true if flush_work_sync() waited for the work to finish execution, 292109383498STejun Heo * %false if it was already idle. 292209383498STejun Heo */ 292309383498STejun Heo bool flush_work_sync(struct work_struct *work) 292409383498STejun Heo { 292509383498STejun Heo struct wq_barrier barr; 292609383498STejun Heo bool pending, waited; 292709383498STejun Heo 292809383498STejun Heo /* we'll wait for executions separately, queue barr only if pending */ 292909383498STejun Heo pending = start_flush_work(work, &barr, false); 293009383498STejun Heo 293109383498STejun Heo /* wait for executions to finish */ 293209383498STejun Heo waited = wait_on_work(work); 293309383498STejun Heo 293409383498STejun Heo /* wait for the pending one */ 293509383498STejun Heo if (pending) { 293609383498STejun Heo wait_for_completion(&barr.done); 293709383498STejun Heo destroy_work_on_stack(&barr.work); 293809383498STejun Heo } 293909383498STejun Heo 294009383498STejun Heo return pending || waited; 294109383498STejun Heo } 294209383498STejun Heo EXPORT_SYMBOL_GPL(flush_work_sync); 294309383498STejun Heo 294436e227d2STejun Heo static bool __cancel_work_timer(struct work_struct *work, bool is_dwork) 29451f1f642eSOleg Nesterov { 2946bbb68dfaSTejun Heo unsigned long flags; 29471f1f642eSOleg Nesterov int ret; 29481f1f642eSOleg Nesterov 29491f1f642eSOleg Nesterov do { 2950bbb68dfaSTejun Heo ret = try_to_grab_pending(work, is_dwork, &flags); 2951bbb68dfaSTejun Heo /* 2952bbb68dfaSTejun Heo * If someone else is canceling, wait for the same event it 2953bbb68dfaSTejun Heo * would be waiting for before retrying. 2954bbb68dfaSTejun Heo */ 2955bbb68dfaSTejun Heo if (unlikely(ret == -ENOENT)) 29561f1f642eSOleg Nesterov wait_on_work(work); 29571f1f642eSOleg Nesterov } while (unlikely(ret < 0)); 29581f1f642eSOleg Nesterov 2959bbb68dfaSTejun Heo /* tell other tasks trying to grab @work to back off */ 2960bbb68dfaSTejun Heo mark_work_canceling(work); 2961bbb68dfaSTejun Heo local_irq_restore(flags); 2962bbb68dfaSTejun Heo 2963bbb68dfaSTejun Heo wait_on_work(work); 29647a22ad75STejun Heo clear_work_data(work); 29651f1f642eSOleg Nesterov return ret; 29661f1f642eSOleg Nesterov } 29671f1f642eSOleg Nesterov 29686e84d644SOleg Nesterov /** 2969401a8d04STejun Heo * cancel_work_sync - cancel a work and wait for it to finish 2970401a8d04STejun Heo * @work: the work to cancel 29716e84d644SOleg Nesterov * 2972401a8d04STejun Heo * Cancel @work and wait for its execution to finish. This function 2973401a8d04STejun Heo * can be used even if the work re-queues itself or migrates to 2974401a8d04STejun Heo * another workqueue. On return from this function, @work is 2975401a8d04STejun Heo * guaranteed to be not pending or executing on any CPU. 29761f1f642eSOleg Nesterov * 2977401a8d04STejun Heo * cancel_work_sync(&delayed_work->work) must not be used for 2978401a8d04STejun Heo * delayed_work's. Use cancel_delayed_work_sync() instead. 29796e84d644SOleg Nesterov * 2980401a8d04STejun Heo * The caller must ensure that the workqueue on which @work was last 29816e84d644SOleg Nesterov * queued can't be destroyed before this function returns. 2982401a8d04STejun Heo * 2983401a8d04STejun Heo * RETURNS: 2984401a8d04STejun Heo * %true if @work was pending, %false otherwise. 29856e84d644SOleg Nesterov */ 2986401a8d04STejun Heo bool cancel_work_sync(struct work_struct *work) 29876e84d644SOleg Nesterov { 298836e227d2STejun Heo return __cancel_work_timer(work, false); 2989b89deed3SOleg Nesterov } 299028e53bddSOleg Nesterov EXPORT_SYMBOL_GPL(cancel_work_sync); 2991b89deed3SOleg Nesterov 29926e84d644SOleg Nesterov /** 2993401a8d04STejun Heo * flush_delayed_work - wait for a dwork to finish executing the last queueing 2994401a8d04STejun Heo * @dwork: the delayed work to flush 29956e84d644SOleg Nesterov * 2996401a8d04STejun Heo * Delayed timer is cancelled and the pending work is queued for 2997401a8d04STejun Heo * immediate execution. Like flush_work(), this function only 2998401a8d04STejun Heo * considers the last queueing instance of @dwork. 29991f1f642eSOleg Nesterov * 3000401a8d04STejun Heo * RETURNS: 3001401a8d04STejun Heo * %true if flush_work() waited for the work to finish execution, 3002401a8d04STejun Heo * %false if it was already idle. 30036e84d644SOleg Nesterov */ 3004401a8d04STejun Heo bool flush_delayed_work(struct delayed_work *dwork) 3005401a8d04STejun Heo { 30068930cabaSTejun Heo local_irq_disable(); 3007401a8d04STejun Heo if (del_timer_sync(&dwork->timer)) 30081265057fSTejun Heo __queue_work(dwork->cpu, 3009401a8d04STejun Heo get_work_cwq(&dwork->work)->wq, &dwork->work); 30108930cabaSTejun Heo local_irq_enable(); 3011401a8d04STejun Heo return flush_work(&dwork->work); 3012401a8d04STejun Heo } 3013401a8d04STejun Heo EXPORT_SYMBOL(flush_delayed_work); 3014401a8d04STejun Heo 3015401a8d04STejun Heo /** 301609383498STejun Heo * flush_delayed_work_sync - wait for a dwork to finish 301709383498STejun Heo * @dwork: the delayed work to flush 301809383498STejun Heo * 301909383498STejun Heo * Delayed timer is cancelled and the pending work is queued for 302009383498STejun Heo * execution immediately. Other than timer handling, its behavior 302109383498STejun Heo * is identical to flush_work_sync(). 302209383498STejun Heo * 302309383498STejun Heo * RETURNS: 302409383498STejun Heo * %true if flush_work_sync() waited for the work to finish execution, 302509383498STejun Heo * %false if it was already idle. 302609383498STejun Heo */ 302709383498STejun Heo bool flush_delayed_work_sync(struct delayed_work *dwork) 302809383498STejun Heo { 30298930cabaSTejun Heo local_irq_disable(); 303009383498STejun Heo if (del_timer_sync(&dwork->timer)) 30311265057fSTejun Heo __queue_work(dwork->cpu, 303209383498STejun Heo get_work_cwq(&dwork->work)->wq, &dwork->work); 30338930cabaSTejun Heo local_irq_enable(); 303409383498STejun Heo return flush_work_sync(&dwork->work); 303509383498STejun Heo } 303609383498STejun Heo EXPORT_SYMBOL(flush_delayed_work_sync); 303709383498STejun Heo 303809383498STejun Heo /** 3039401a8d04STejun Heo * cancel_delayed_work_sync - cancel a delayed work and wait for it to finish 3040401a8d04STejun Heo * @dwork: the delayed work cancel 3041401a8d04STejun Heo * 3042401a8d04STejun Heo * This is cancel_work_sync() for delayed works. 3043401a8d04STejun Heo * 3044401a8d04STejun Heo * RETURNS: 3045401a8d04STejun Heo * %true if @dwork was pending, %false otherwise. 3046401a8d04STejun Heo */ 3047401a8d04STejun Heo bool cancel_delayed_work_sync(struct delayed_work *dwork) 30486e84d644SOleg Nesterov { 304936e227d2STejun Heo return __cancel_work_timer(&dwork->work, true); 30506e84d644SOleg Nesterov } 3051f5a421a4SOleg Nesterov EXPORT_SYMBOL(cancel_delayed_work_sync); 30521da177e4SLinus Torvalds 3053d4283e93STejun Heo /** 30540a13c00eSTejun Heo * schedule_work_on - put work task on a specific cpu 30550a13c00eSTejun Heo * @cpu: cpu to put the work task on 30560a13c00eSTejun Heo * @work: job to be done 30570a13c00eSTejun Heo * 30580a13c00eSTejun Heo * This puts a job on a specific cpu 30590a13c00eSTejun Heo */ 3060d4283e93STejun Heo bool schedule_work_on(int cpu, struct work_struct *work) 30610a13c00eSTejun Heo { 30620a13c00eSTejun Heo return queue_work_on(cpu, system_wq, work); 30630a13c00eSTejun Heo } 30640a13c00eSTejun Heo EXPORT_SYMBOL(schedule_work_on); 30650a13c00eSTejun Heo 30660fcb78c2SRolf Eike Beer /** 30670fcb78c2SRolf Eike Beer * schedule_work - put work task in global workqueue 30680fcb78c2SRolf Eike Beer * @work: job to be done 30690fcb78c2SRolf Eike Beer * 3070d4283e93STejun Heo * Returns %false if @work was already on the kernel-global workqueue and 3071d4283e93STejun Heo * %true otherwise. 30725b0f437dSBart Van Assche * 30735b0f437dSBart Van Assche * This puts a job in the kernel-global workqueue if it was not already 30745b0f437dSBart Van Assche * queued and leaves it in the same position on the kernel-global 30755b0f437dSBart Van Assche * workqueue otherwise. 30760fcb78c2SRolf Eike Beer */ 3077d4283e93STejun Heo bool schedule_work(struct work_struct *work) 30781da177e4SLinus Torvalds { 3079d320c038STejun Heo return queue_work(system_wq, work); 30801da177e4SLinus Torvalds } 3081ae90dd5dSDave Jones EXPORT_SYMBOL(schedule_work); 30821da177e4SLinus Torvalds 30830fcb78c2SRolf Eike Beer /** 30840fcb78c2SRolf Eike Beer * schedule_delayed_work_on - queue work in global workqueue on CPU after delay 30850fcb78c2SRolf Eike Beer * @cpu: cpu to use 308652bad64dSDavid Howells * @dwork: job to be done 30870fcb78c2SRolf Eike Beer * @delay: number of jiffies to wait 30880fcb78c2SRolf Eike Beer * 30890fcb78c2SRolf Eike Beer * After waiting for a given time this puts a job in the kernel-global 30900fcb78c2SRolf Eike Beer * workqueue on the specified CPU. 30910fcb78c2SRolf Eike Beer */ 3092d4283e93STejun Heo bool schedule_delayed_work_on(int cpu, struct delayed_work *dwork, 3093d4283e93STejun Heo unsigned long delay) 30941da177e4SLinus Torvalds { 3095d320c038STejun Heo return queue_delayed_work_on(cpu, system_wq, dwork, delay); 30961da177e4SLinus Torvalds } 3097ae90dd5dSDave Jones EXPORT_SYMBOL(schedule_delayed_work_on); 30981da177e4SLinus Torvalds 3099b6136773SAndrew Morton /** 31000a13c00eSTejun Heo * schedule_delayed_work - put work task in global workqueue after delay 31010a13c00eSTejun Heo * @dwork: job to be done 31020a13c00eSTejun Heo * @delay: number of jiffies to wait or 0 for immediate execution 31030a13c00eSTejun Heo * 31040a13c00eSTejun Heo * After waiting for a given time this puts a job in the kernel-global 31050a13c00eSTejun Heo * workqueue. 31060a13c00eSTejun Heo */ 3107d4283e93STejun Heo bool schedule_delayed_work(struct delayed_work *dwork, unsigned long delay) 31080a13c00eSTejun Heo { 31090a13c00eSTejun Heo return queue_delayed_work(system_wq, dwork, delay); 31100a13c00eSTejun Heo } 31110a13c00eSTejun Heo EXPORT_SYMBOL(schedule_delayed_work); 31120a13c00eSTejun Heo 31130a13c00eSTejun Heo /** 311431ddd871STejun Heo * schedule_on_each_cpu - execute a function synchronously on each online CPU 3115b6136773SAndrew Morton * @func: the function to call 3116b6136773SAndrew Morton * 311731ddd871STejun Heo * schedule_on_each_cpu() executes @func on each online CPU using the 311831ddd871STejun Heo * system workqueue and blocks until all CPUs have completed. 3119b6136773SAndrew Morton * schedule_on_each_cpu() is very slow. 312031ddd871STejun Heo * 312131ddd871STejun Heo * RETURNS: 312231ddd871STejun Heo * 0 on success, -errno on failure. 3123b6136773SAndrew Morton */ 312465f27f38SDavid Howells int schedule_on_each_cpu(work_func_t func) 312515316ba8SChristoph Lameter { 312615316ba8SChristoph Lameter int cpu; 312738f51568SNamhyung Kim struct work_struct __percpu *works; 312815316ba8SChristoph Lameter 3129b6136773SAndrew Morton works = alloc_percpu(struct work_struct); 3130b6136773SAndrew Morton if (!works) 313115316ba8SChristoph Lameter return -ENOMEM; 3132b6136773SAndrew Morton 313395402b38SGautham R Shenoy get_online_cpus(); 313493981800STejun Heo 313515316ba8SChristoph Lameter for_each_online_cpu(cpu) { 31369bfb1839SIngo Molnar struct work_struct *work = per_cpu_ptr(works, cpu); 31379bfb1839SIngo Molnar 31389bfb1839SIngo Molnar INIT_WORK(work, func); 31398de6d308SOleg Nesterov schedule_work_on(cpu, work); 314015316ba8SChristoph Lameter } 314193981800STejun Heo 314293981800STejun Heo for_each_online_cpu(cpu) 31438616a89aSOleg Nesterov flush_work(per_cpu_ptr(works, cpu)); 314493981800STejun Heo 314595402b38SGautham R Shenoy put_online_cpus(); 3146b6136773SAndrew Morton free_percpu(works); 314715316ba8SChristoph Lameter return 0; 314815316ba8SChristoph Lameter } 314915316ba8SChristoph Lameter 3150eef6a7d5SAlan Stern /** 3151eef6a7d5SAlan Stern * flush_scheduled_work - ensure that any scheduled work has run to completion. 3152eef6a7d5SAlan Stern * 3153eef6a7d5SAlan Stern * Forces execution of the kernel-global workqueue and blocks until its 3154eef6a7d5SAlan Stern * completion. 3155eef6a7d5SAlan Stern * 3156eef6a7d5SAlan Stern * Think twice before calling this function! It's very easy to get into 3157eef6a7d5SAlan Stern * trouble if you don't take great care. Either of the following situations 3158eef6a7d5SAlan Stern * will lead to deadlock: 3159eef6a7d5SAlan Stern * 3160eef6a7d5SAlan Stern * One of the work items currently on the workqueue needs to acquire 3161eef6a7d5SAlan Stern * a lock held by your code or its caller. 3162eef6a7d5SAlan Stern * 3163eef6a7d5SAlan Stern * Your code is running in the context of a work routine. 3164eef6a7d5SAlan Stern * 3165eef6a7d5SAlan Stern * They will be detected by lockdep when they occur, but the first might not 3166eef6a7d5SAlan Stern * occur very often. It depends on what work items are on the workqueue and 3167eef6a7d5SAlan Stern * what locks they need, which you have no control over. 3168eef6a7d5SAlan Stern * 3169eef6a7d5SAlan Stern * In most situations flushing the entire workqueue is overkill; you merely 3170eef6a7d5SAlan Stern * need to know that a particular work item isn't queued and isn't running. 3171eef6a7d5SAlan Stern * In such cases you should use cancel_delayed_work_sync() or 3172eef6a7d5SAlan Stern * cancel_work_sync() instead. 3173eef6a7d5SAlan Stern */ 31741da177e4SLinus Torvalds void flush_scheduled_work(void) 31751da177e4SLinus Torvalds { 3176d320c038STejun Heo flush_workqueue(system_wq); 31771da177e4SLinus Torvalds } 3178ae90dd5dSDave Jones EXPORT_SYMBOL(flush_scheduled_work); 31791da177e4SLinus Torvalds 31801da177e4SLinus Torvalds /** 31811fa44ecaSJames Bottomley * execute_in_process_context - reliably execute the routine with user context 31821fa44ecaSJames Bottomley * @fn: the function to execute 31831fa44ecaSJames Bottomley * @ew: guaranteed storage for the execute work structure (must 31841fa44ecaSJames Bottomley * be available when the work executes) 31851fa44ecaSJames Bottomley * 31861fa44ecaSJames Bottomley * Executes the function immediately if process context is available, 31871fa44ecaSJames Bottomley * otherwise schedules the function for delayed execution. 31881fa44ecaSJames Bottomley * 31891fa44ecaSJames Bottomley * Returns: 0 - function was executed 31901fa44ecaSJames Bottomley * 1 - function was scheduled for execution 31911fa44ecaSJames Bottomley */ 319265f27f38SDavid Howells int execute_in_process_context(work_func_t fn, struct execute_work *ew) 31931fa44ecaSJames Bottomley { 31941fa44ecaSJames Bottomley if (!in_interrupt()) { 319565f27f38SDavid Howells fn(&ew->work); 31961fa44ecaSJames Bottomley return 0; 31971fa44ecaSJames Bottomley } 31981fa44ecaSJames Bottomley 319965f27f38SDavid Howells INIT_WORK(&ew->work, fn); 32001fa44ecaSJames Bottomley schedule_work(&ew->work); 32011fa44ecaSJames Bottomley 32021fa44ecaSJames Bottomley return 1; 32031fa44ecaSJames Bottomley } 32041fa44ecaSJames Bottomley EXPORT_SYMBOL_GPL(execute_in_process_context); 32051fa44ecaSJames Bottomley 32061da177e4SLinus Torvalds int keventd_up(void) 32071da177e4SLinus Torvalds { 3208d320c038STejun Heo return system_wq != NULL; 32091da177e4SLinus Torvalds } 32101da177e4SLinus Torvalds 3211bdbc5dd7STejun Heo static int alloc_cwqs(struct workqueue_struct *wq) 32121da177e4SLinus Torvalds { 32133af24433SOleg Nesterov /* 32140f900049STejun Heo * cwqs are forced aligned according to WORK_STRUCT_FLAG_BITS. 32150f900049STejun Heo * Make sure that the alignment isn't lower than that of 32160f900049STejun Heo * unsigned long long. 32173af24433SOleg Nesterov */ 32180f900049STejun Heo const size_t size = sizeof(struct cpu_workqueue_struct); 32190f900049STejun Heo const size_t align = max_t(size_t, 1 << WORK_STRUCT_FLAG_BITS, 32200f900049STejun Heo __alignof__(unsigned long long)); 32213af24433SOleg Nesterov 3222e06ffa1eSLai Jiangshan if (!(wq->flags & WQ_UNBOUND)) 3223f3421797STejun Heo wq->cpu_wq.pcpu = __alloc_percpu(size, align); 3224931ac77eSTejun Heo else { 32250f900049STejun Heo void *ptr; 3226e1d8aa9fSFrederic Weisbecker 32270f900049STejun Heo /* 3228f3421797STejun Heo * Allocate enough room to align cwq and put an extra 3229f3421797STejun Heo * pointer at the end pointing back to the originally 3230f3421797STejun Heo * allocated pointer which will be used for free. 32310f900049STejun Heo */ 3232bdbc5dd7STejun Heo ptr = kzalloc(size + align + sizeof(void *), GFP_KERNEL); 3233bdbc5dd7STejun Heo if (ptr) { 3234bdbc5dd7STejun Heo wq->cpu_wq.single = PTR_ALIGN(ptr, align); 3235bdbc5dd7STejun Heo *(void **)(wq->cpu_wq.single + 1) = ptr; 3236bdbc5dd7STejun Heo } 32373af24433SOleg Nesterov } 32383af24433SOleg Nesterov 32390415b00dSTejun Heo /* just in case, make sure it's actually aligned */ 3240bdbc5dd7STejun Heo BUG_ON(!IS_ALIGNED(wq->cpu_wq.v, align)); 3241bdbc5dd7STejun Heo return wq->cpu_wq.v ? 0 : -ENOMEM; 32420f900049STejun Heo } 32430f900049STejun Heo 3244bdbc5dd7STejun Heo static void free_cwqs(struct workqueue_struct *wq) 324506ba38a9SOleg Nesterov { 3246e06ffa1eSLai Jiangshan if (!(wq->flags & WQ_UNBOUND)) 3247bdbc5dd7STejun Heo free_percpu(wq->cpu_wq.pcpu); 3248f3421797STejun Heo else if (wq->cpu_wq.single) { 3249f3421797STejun Heo /* the pointer to free is stored right after the cwq */ 3250f3421797STejun Heo kfree(*(void **)(wq->cpu_wq.single + 1)); 325106ba38a9SOleg Nesterov } 325206ba38a9SOleg Nesterov } 325306ba38a9SOleg Nesterov 3254f3421797STejun Heo static int wq_clamp_max_active(int max_active, unsigned int flags, 3255f3421797STejun Heo const char *name) 3256b71ab8c2STejun Heo { 3257f3421797STejun Heo int lim = flags & WQ_UNBOUND ? WQ_UNBOUND_MAX_ACTIVE : WQ_MAX_ACTIVE; 3258f3421797STejun Heo 3259f3421797STejun Heo if (max_active < 1 || max_active > lim) 3260b71ab8c2STejun Heo printk(KERN_WARNING "workqueue: max_active %d requested for %s " 3261b71ab8c2STejun Heo "is out of range, clamping between %d and %d\n", 3262f3421797STejun Heo max_active, name, 1, lim); 3263b71ab8c2STejun Heo 3264f3421797STejun Heo return clamp_val(max_active, 1, lim); 3265b71ab8c2STejun Heo } 3266b71ab8c2STejun Heo 3267b196be89STejun Heo struct workqueue_struct *__alloc_workqueue_key(const char *fmt, 326897e37d7bSTejun Heo unsigned int flags, 32691e19ffc6STejun Heo int max_active, 3270eb13ba87SJohannes Berg struct lock_class_key *key, 3271b196be89STejun Heo const char *lock_name, ...) 32723af24433SOleg Nesterov { 3273b196be89STejun Heo va_list args, args1; 32743af24433SOleg Nesterov struct workqueue_struct *wq; 3275c34056a3STejun Heo unsigned int cpu; 3276b196be89STejun Heo size_t namelen; 3277b196be89STejun Heo 3278b196be89STejun Heo /* determine namelen, allocate wq and format name */ 3279b196be89STejun Heo va_start(args, lock_name); 3280b196be89STejun Heo va_copy(args1, args); 3281b196be89STejun Heo namelen = vsnprintf(NULL, 0, fmt, args) + 1; 3282b196be89STejun Heo 3283b196be89STejun Heo wq = kzalloc(sizeof(*wq) + namelen, GFP_KERNEL); 3284b196be89STejun Heo if (!wq) 3285b196be89STejun Heo goto err; 3286b196be89STejun Heo 3287b196be89STejun Heo vsnprintf(wq->name, namelen, fmt, args1); 3288b196be89STejun Heo va_end(args); 3289b196be89STejun Heo va_end(args1); 32903af24433SOleg Nesterov 3291f3421797STejun Heo /* 32926370a6adSTejun Heo * Workqueues which may be used during memory reclaim should 32936370a6adSTejun Heo * have a rescuer to guarantee forward progress. 32946370a6adSTejun Heo */ 32956370a6adSTejun Heo if (flags & WQ_MEM_RECLAIM) 32966370a6adSTejun Heo flags |= WQ_RESCUER; 32976370a6adSTejun Heo 3298d320c038STejun Heo max_active = max_active ?: WQ_DFL_ACTIVE; 3299b196be89STejun Heo max_active = wq_clamp_max_active(max_active, flags, wq->name); 33003af24433SOleg Nesterov 3301b196be89STejun Heo /* init wq */ 330297e37d7bSTejun Heo wq->flags = flags; 3303a0a1a5fdSTejun Heo wq->saved_max_active = max_active; 330473f53c4aSTejun Heo mutex_init(&wq->flush_mutex); 330573f53c4aSTejun Heo atomic_set(&wq->nr_cwqs_to_flush, 0); 330673f53c4aSTejun Heo INIT_LIST_HEAD(&wq->flusher_queue); 330773f53c4aSTejun Heo INIT_LIST_HEAD(&wq->flusher_overflow); 33083af24433SOleg Nesterov 3309eb13ba87SJohannes Berg lockdep_init_map(&wq->lockdep_map, lock_name, key, 0); 3310cce1a165SOleg Nesterov INIT_LIST_HEAD(&wq->list); 33113af24433SOleg Nesterov 3312bdbc5dd7STejun Heo if (alloc_cwqs(wq) < 0) 3313bdbc5dd7STejun Heo goto err; 3314bdbc5dd7STejun Heo 3315f3421797STejun Heo for_each_cwq_cpu(cpu, wq) { 33161537663fSTejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 33178b03ae3cSTejun Heo struct global_cwq *gcwq = get_gcwq(cpu); 33183270476aSTejun Heo int pool_idx = (bool)(flags & WQ_HIGHPRI); 33191537663fSTejun Heo 33200f900049STejun Heo BUG_ON((unsigned long)cwq & WORK_STRUCT_FLAG_MASK); 33213270476aSTejun Heo cwq->pool = &gcwq->pools[pool_idx]; 3322c34056a3STejun Heo cwq->wq = wq; 332373f53c4aSTejun Heo cwq->flush_color = -1; 33241e19ffc6STejun Heo cwq->max_active = max_active; 33251e19ffc6STejun Heo INIT_LIST_HEAD(&cwq->delayed_works); 3326e22bee78STejun Heo } 33271537663fSTejun Heo 3328e22bee78STejun Heo if (flags & WQ_RESCUER) { 3329e22bee78STejun Heo struct worker *rescuer; 3330e22bee78STejun Heo 3331f2e005aaSTejun Heo if (!alloc_mayday_mask(&wq->mayday_mask, GFP_KERNEL)) 3332e22bee78STejun Heo goto err; 3333e22bee78STejun Heo 3334e22bee78STejun Heo wq->rescuer = rescuer = alloc_worker(); 3335e22bee78STejun Heo if (!rescuer) 3336e22bee78STejun Heo goto err; 3337e22bee78STejun Heo 3338b196be89STejun Heo rescuer->task = kthread_create(rescuer_thread, wq, "%s", 3339b196be89STejun Heo wq->name); 3340e22bee78STejun Heo if (IS_ERR(rescuer->task)) 3341e22bee78STejun Heo goto err; 3342e22bee78STejun Heo 3343e22bee78STejun Heo rescuer->task->flags |= PF_THREAD_BOUND; 3344e22bee78STejun Heo wake_up_process(rescuer->task); 33453af24433SOleg Nesterov } 33461537663fSTejun Heo 33473af24433SOleg Nesterov /* 3348a0a1a5fdSTejun Heo * workqueue_lock protects global freeze state and workqueues 3349a0a1a5fdSTejun Heo * list. Grab it, set max_active accordingly and add the new 3350a0a1a5fdSTejun Heo * workqueue to workqueues list. 33513af24433SOleg Nesterov */ 33523af24433SOleg Nesterov spin_lock(&workqueue_lock); 3353a0a1a5fdSTejun Heo 335458a69cb4STejun Heo if (workqueue_freezing && wq->flags & WQ_FREEZABLE) 3355f3421797STejun Heo for_each_cwq_cpu(cpu, wq) 3356a0a1a5fdSTejun Heo get_cwq(cpu, wq)->max_active = 0; 3357a0a1a5fdSTejun Heo 33583af24433SOleg Nesterov list_add(&wq->list, &workqueues); 3359a0a1a5fdSTejun Heo 33603af24433SOleg Nesterov spin_unlock(&workqueue_lock); 33613af24433SOleg Nesterov 33623af24433SOleg Nesterov return wq; 33634690c4abSTejun Heo err: 33644690c4abSTejun Heo if (wq) { 3365bdbc5dd7STejun Heo free_cwqs(wq); 3366f2e005aaSTejun Heo free_mayday_mask(wq->mayday_mask); 3367e22bee78STejun Heo kfree(wq->rescuer); 33684690c4abSTejun Heo kfree(wq); 33693af24433SOleg Nesterov } 33704690c4abSTejun Heo return NULL; 33711da177e4SLinus Torvalds } 3372d320c038STejun Heo EXPORT_SYMBOL_GPL(__alloc_workqueue_key); 33731da177e4SLinus Torvalds 33743af24433SOleg Nesterov /** 33753af24433SOleg Nesterov * destroy_workqueue - safely terminate a workqueue 33763af24433SOleg Nesterov * @wq: target workqueue 33773af24433SOleg Nesterov * 33783af24433SOleg Nesterov * Safely destroy a workqueue. All work currently pending will be done first. 33793af24433SOleg Nesterov */ 33803af24433SOleg Nesterov void destroy_workqueue(struct workqueue_struct *wq) 33813af24433SOleg Nesterov { 3382c8e55f36STejun Heo unsigned int cpu; 33833af24433SOleg Nesterov 33849c5a2ba7STejun Heo /* drain it before proceeding with destruction */ 33859c5a2ba7STejun Heo drain_workqueue(wq); 3386c8efcc25STejun Heo 3387a0a1a5fdSTejun Heo /* 3388a0a1a5fdSTejun Heo * wq list is used to freeze wq, remove from list after 3389a0a1a5fdSTejun Heo * flushing is complete in case freeze races us. 3390a0a1a5fdSTejun Heo */ 339195402b38SGautham R Shenoy spin_lock(&workqueue_lock); 33923af24433SOleg Nesterov list_del(&wq->list); 339395402b38SGautham R Shenoy spin_unlock(&workqueue_lock); 33943af24433SOleg Nesterov 3395e22bee78STejun Heo /* sanity check */ 3396f3421797STejun Heo for_each_cwq_cpu(cpu, wq) { 339773f53c4aSTejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 339873f53c4aSTejun Heo int i; 33993af24433SOleg Nesterov 340073f53c4aSTejun Heo for (i = 0; i < WORK_NR_COLORS; i++) 340173f53c4aSTejun Heo BUG_ON(cwq->nr_in_flight[i]); 34021e19ffc6STejun Heo BUG_ON(cwq->nr_active); 34031e19ffc6STejun Heo BUG_ON(!list_empty(&cwq->delayed_works)); 340473f53c4aSTejun Heo } 34051537663fSTejun Heo 3406e22bee78STejun Heo if (wq->flags & WQ_RESCUER) { 3407e22bee78STejun Heo kthread_stop(wq->rescuer->task); 3408f2e005aaSTejun Heo free_mayday_mask(wq->mayday_mask); 34098d9df9f0SXiaotian Feng kfree(wq->rescuer); 3410e22bee78STejun Heo } 3411e22bee78STejun Heo 3412bdbc5dd7STejun Heo free_cwqs(wq); 34133af24433SOleg Nesterov kfree(wq); 34143af24433SOleg Nesterov } 34153af24433SOleg Nesterov EXPORT_SYMBOL_GPL(destroy_workqueue); 34163af24433SOleg Nesterov 3417dcd989cbSTejun Heo /** 3418dcd989cbSTejun Heo * workqueue_set_max_active - adjust max_active of a workqueue 3419dcd989cbSTejun Heo * @wq: target workqueue 3420dcd989cbSTejun Heo * @max_active: new max_active value. 3421dcd989cbSTejun Heo * 3422dcd989cbSTejun Heo * Set max_active of @wq to @max_active. 3423dcd989cbSTejun Heo * 3424dcd989cbSTejun Heo * CONTEXT: 3425dcd989cbSTejun Heo * Don't call from IRQ context. 3426dcd989cbSTejun Heo */ 3427dcd989cbSTejun Heo void workqueue_set_max_active(struct workqueue_struct *wq, int max_active) 3428dcd989cbSTejun Heo { 3429dcd989cbSTejun Heo unsigned int cpu; 3430dcd989cbSTejun Heo 3431f3421797STejun Heo max_active = wq_clamp_max_active(max_active, wq->flags, wq->name); 3432dcd989cbSTejun Heo 3433dcd989cbSTejun Heo spin_lock(&workqueue_lock); 3434dcd989cbSTejun Heo 3435dcd989cbSTejun Heo wq->saved_max_active = max_active; 3436dcd989cbSTejun Heo 3437f3421797STejun Heo for_each_cwq_cpu(cpu, wq) { 3438dcd989cbSTejun Heo struct global_cwq *gcwq = get_gcwq(cpu); 3439dcd989cbSTejun Heo 3440dcd989cbSTejun Heo spin_lock_irq(&gcwq->lock); 3441dcd989cbSTejun Heo 344258a69cb4STejun Heo if (!(wq->flags & WQ_FREEZABLE) || 3443dcd989cbSTejun Heo !(gcwq->flags & GCWQ_FREEZING)) 3444dcd989cbSTejun Heo get_cwq(gcwq->cpu, wq)->max_active = max_active; 3445dcd989cbSTejun Heo 3446dcd989cbSTejun Heo spin_unlock_irq(&gcwq->lock); 3447dcd989cbSTejun Heo } 3448dcd989cbSTejun Heo 3449dcd989cbSTejun Heo spin_unlock(&workqueue_lock); 3450dcd989cbSTejun Heo } 3451dcd989cbSTejun Heo EXPORT_SYMBOL_GPL(workqueue_set_max_active); 3452dcd989cbSTejun Heo 3453dcd989cbSTejun Heo /** 3454dcd989cbSTejun Heo * workqueue_congested - test whether a workqueue is congested 3455dcd989cbSTejun Heo * @cpu: CPU in question 3456dcd989cbSTejun Heo * @wq: target workqueue 3457dcd989cbSTejun Heo * 3458dcd989cbSTejun Heo * Test whether @wq's cpu workqueue for @cpu is congested. There is 3459dcd989cbSTejun Heo * no synchronization around this function and the test result is 3460dcd989cbSTejun Heo * unreliable and only useful as advisory hints or for debugging. 3461dcd989cbSTejun Heo * 3462dcd989cbSTejun Heo * RETURNS: 3463dcd989cbSTejun Heo * %true if congested, %false otherwise. 3464dcd989cbSTejun Heo */ 3465dcd989cbSTejun Heo bool workqueue_congested(unsigned int cpu, struct workqueue_struct *wq) 3466dcd989cbSTejun Heo { 3467dcd989cbSTejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 3468dcd989cbSTejun Heo 3469dcd989cbSTejun Heo return !list_empty(&cwq->delayed_works); 3470dcd989cbSTejun Heo } 3471dcd989cbSTejun Heo EXPORT_SYMBOL_GPL(workqueue_congested); 3472dcd989cbSTejun Heo 3473dcd989cbSTejun Heo /** 3474dcd989cbSTejun Heo * work_cpu - return the last known associated cpu for @work 3475dcd989cbSTejun Heo * @work: the work of interest 3476dcd989cbSTejun Heo * 3477dcd989cbSTejun Heo * RETURNS: 3478bdbc5dd7STejun Heo * CPU number if @work was ever queued. WORK_CPU_NONE otherwise. 3479dcd989cbSTejun Heo */ 3480dcd989cbSTejun Heo unsigned int work_cpu(struct work_struct *work) 3481dcd989cbSTejun Heo { 3482dcd989cbSTejun Heo struct global_cwq *gcwq = get_work_gcwq(work); 3483dcd989cbSTejun Heo 3484bdbc5dd7STejun Heo return gcwq ? gcwq->cpu : WORK_CPU_NONE; 3485dcd989cbSTejun Heo } 3486dcd989cbSTejun Heo EXPORT_SYMBOL_GPL(work_cpu); 3487dcd989cbSTejun Heo 3488dcd989cbSTejun Heo /** 3489dcd989cbSTejun Heo * work_busy - test whether a work is currently pending or running 3490dcd989cbSTejun Heo * @work: the work to be tested 3491dcd989cbSTejun Heo * 3492dcd989cbSTejun Heo * Test whether @work is currently pending or running. There is no 3493dcd989cbSTejun Heo * synchronization around this function and the test result is 3494dcd989cbSTejun Heo * unreliable and only useful as advisory hints or for debugging. 3495dcd989cbSTejun Heo * Especially for reentrant wqs, the pending state might hide the 3496dcd989cbSTejun Heo * running state. 3497dcd989cbSTejun Heo * 3498dcd989cbSTejun Heo * RETURNS: 3499dcd989cbSTejun Heo * OR'd bitmask of WORK_BUSY_* bits. 3500dcd989cbSTejun Heo */ 3501dcd989cbSTejun Heo unsigned int work_busy(struct work_struct *work) 3502dcd989cbSTejun Heo { 3503dcd989cbSTejun Heo struct global_cwq *gcwq = get_work_gcwq(work); 3504dcd989cbSTejun Heo unsigned long flags; 3505dcd989cbSTejun Heo unsigned int ret = 0; 3506dcd989cbSTejun Heo 3507dcd989cbSTejun Heo if (!gcwq) 3508dcd989cbSTejun Heo return false; 3509dcd989cbSTejun Heo 3510dcd989cbSTejun Heo spin_lock_irqsave(&gcwq->lock, flags); 3511dcd989cbSTejun Heo 3512dcd989cbSTejun Heo if (work_pending(work)) 3513dcd989cbSTejun Heo ret |= WORK_BUSY_PENDING; 3514dcd989cbSTejun Heo if (find_worker_executing_work(gcwq, work)) 3515dcd989cbSTejun Heo ret |= WORK_BUSY_RUNNING; 3516dcd989cbSTejun Heo 3517dcd989cbSTejun Heo spin_unlock_irqrestore(&gcwq->lock, flags); 3518dcd989cbSTejun Heo 3519dcd989cbSTejun Heo return ret; 3520dcd989cbSTejun Heo } 3521dcd989cbSTejun Heo EXPORT_SYMBOL_GPL(work_busy); 3522dcd989cbSTejun Heo 3523db7bccf4STejun Heo /* 3524db7bccf4STejun Heo * CPU hotplug. 3525db7bccf4STejun Heo * 3526e22bee78STejun Heo * There are two challenges in supporting CPU hotplug. Firstly, there 3527e22bee78STejun Heo * are a lot of assumptions on strong associations among work, cwq and 3528e22bee78STejun Heo * gcwq which make migrating pending and scheduled works very 3529e22bee78STejun Heo * difficult to implement without impacting hot paths. Secondly, 3530e22bee78STejun Heo * gcwqs serve mix of short, long and very long running works making 3531e22bee78STejun Heo * blocked draining impractical. 3532e22bee78STejun Heo * 3533628c78e7STejun Heo * This is solved by allowing a gcwq to be disassociated from the CPU 3534628c78e7STejun Heo * running as an unbound one and allowing it to be reattached later if the 3535628c78e7STejun Heo * cpu comes back online. 3536db7bccf4STejun Heo */ 3537db7bccf4STejun Heo 353860373152STejun Heo /* claim manager positions of all pools */ 35398db25e78STejun Heo static void gcwq_claim_management_and_lock(struct global_cwq *gcwq) 354060373152STejun Heo { 354160373152STejun Heo struct worker_pool *pool; 354260373152STejun Heo 354360373152STejun Heo for_each_worker_pool(pool, gcwq) 354460373152STejun Heo mutex_lock_nested(&pool->manager_mutex, pool - gcwq->pools); 35458db25e78STejun Heo spin_lock_irq(&gcwq->lock); 354660373152STejun Heo } 354760373152STejun Heo 354860373152STejun Heo /* release manager positions */ 35498db25e78STejun Heo static void gcwq_release_management_and_unlock(struct global_cwq *gcwq) 355060373152STejun Heo { 355160373152STejun Heo struct worker_pool *pool; 355260373152STejun Heo 35538db25e78STejun Heo spin_unlock_irq(&gcwq->lock); 355460373152STejun Heo for_each_worker_pool(pool, gcwq) 355560373152STejun Heo mutex_unlock(&pool->manager_mutex); 355660373152STejun Heo } 355760373152STejun Heo 3558628c78e7STejun Heo static void gcwq_unbind_fn(struct work_struct *work) 3559db7bccf4STejun Heo { 3560628c78e7STejun Heo struct global_cwq *gcwq = get_gcwq(smp_processor_id()); 35614ce62e9eSTejun Heo struct worker_pool *pool; 3562db7bccf4STejun Heo struct worker *worker; 3563db7bccf4STejun Heo struct hlist_node *pos; 3564db7bccf4STejun Heo int i; 3565db7bccf4STejun Heo 3566db7bccf4STejun Heo BUG_ON(gcwq->cpu != smp_processor_id()); 3567db7bccf4STejun Heo 35688db25e78STejun Heo gcwq_claim_management_and_lock(gcwq); 3569e22bee78STejun Heo 3570f2d5a0eeSTejun Heo /* 3571f2d5a0eeSTejun Heo * We've claimed all manager positions. Make all workers unbound 3572f2d5a0eeSTejun Heo * and set DISASSOCIATED. Before this, all workers except for the 3573f2d5a0eeSTejun Heo * ones which are still executing works from before the last CPU 3574f2d5a0eeSTejun Heo * down must be on the cpu. After this, they may become diasporas. 3575f2d5a0eeSTejun Heo */ 357660373152STejun Heo for_each_worker_pool(pool, gcwq) 35774ce62e9eSTejun Heo list_for_each_entry(worker, &pool->idle_list, entry) 3578403c821dSTejun Heo worker->flags |= WORKER_UNBOUND; 3579db7bccf4STejun Heo 3580db7bccf4STejun Heo for_each_busy_worker(worker, i, pos, gcwq) 3581403c821dSTejun Heo worker->flags |= WORKER_UNBOUND; 3582db7bccf4STejun Heo 3583f2d5a0eeSTejun Heo gcwq->flags |= GCWQ_DISASSOCIATED; 3584f2d5a0eeSTejun Heo 35858db25e78STejun Heo gcwq_release_management_and_unlock(gcwq); 3586e22bee78STejun Heo 3587e22bee78STejun Heo /* 3588628c78e7STejun Heo * Call schedule() so that we cross rq->lock and thus can guarantee 3589628c78e7STejun Heo * sched callbacks see the %WORKER_UNBOUND flag. This is necessary 3590628c78e7STejun Heo * as scheduler callbacks may be invoked from other cpus. 3591628c78e7STejun Heo */ 3592628c78e7STejun Heo schedule(); 3593628c78e7STejun Heo 3594628c78e7STejun Heo /* 3595628c78e7STejun Heo * Sched callbacks are disabled now. Zap nr_running. After this, 3596628c78e7STejun Heo * nr_running stays zero and need_more_worker() and keep_working() 3597628c78e7STejun Heo * are always true as long as the worklist is not empty. @gcwq now 3598628c78e7STejun Heo * behaves as unbound (in terms of concurrency management) gcwq 3599628c78e7STejun Heo * which is served by workers tied to the CPU. 3600628c78e7STejun Heo * 3601628c78e7STejun Heo * On return from this function, the current worker would trigger 3602628c78e7STejun Heo * unbound chain execution of pending work items if other workers 3603628c78e7STejun Heo * didn't already. 3604e22bee78STejun Heo */ 36054ce62e9eSTejun Heo for_each_worker_pool(pool, gcwq) 36064ce62e9eSTejun Heo atomic_set(get_pool_nr_running(pool), 0); 3607db7bccf4STejun Heo } 3608db7bccf4STejun Heo 36098db25e78STejun Heo /* 36108db25e78STejun Heo * Workqueues should be brought up before normal priority CPU notifiers. 36118db25e78STejun Heo * This will be registered high priority CPU notifier. 36128db25e78STejun Heo */ 36138db25e78STejun Heo static int __devinit workqueue_cpu_up_callback(struct notifier_block *nfb, 36141da177e4SLinus Torvalds unsigned long action, 36151da177e4SLinus Torvalds void *hcpu) 36161da177e4SLinus Torvalds { 36173af24433SOleg Nesterov unsigned int cpu = (unsigned long)hcpu; 3618db7bccf4STejun Heo struct global_cwq *gcwq = get_gcwq(cpu); 36194ce62e9eSTejun Heo struct worker_pool *pool; 36201da177e4SLinus Torvalds 36218db25e78STejun Heo switch (action & ~CPU_TASKS_FROZEN) { 36223af24433SOleg Nesterov case CPU_UP_PREPARE: 36234ce62e9eSTejun Heo for_each_worker_pool(pool, gcwq) { 36243ce63377STejun Heo struct worker *worker; 36253ce63377STejun Heo 36263ce63377STejun Heo if (pool->nr_workers) 36273ce63377STejun Heo continue; 36283ce63377STejun Heo 36293ce63377STejun Heo worker = create_worker(pool); 36303ce63377STejun Heo if (!worker) 36313ce63377STejun Heo return NOTIFY_BAD; 36323ce63377STejun Heo 36333ce63377STejun Heo spin_lock_irq(&gcwq->lock); 36343ce63377STejun Heo start_worker(worker); 36353ce63377STejun Heo spin_unlock_irq(&gcwq->lock); 36363af24433SOleg Nesterov } 36371da177e4SLinus Torvalds break; 36381da177e4SLinus Torvalds 363965758202STejun Heo case CPU_DOWN_FAILED: 364065758202STejun Heo case CPU_ONLINE: 36418db25e78STejun Heo gcwq_claim_management_and_lock(gcwq); 36428db25e78STejun Heo gcwq->flags &= ~GCWQ_DISASSOCIATED; 36438db25e78STejun Heo rebind_workers(gcwq); 36448db25e78STejun Heo gcwq_release_management_and_unlock(gcwq); 36458db25e78STejun Heo break; 364665758202STejun Heo } 364765758202STejun Heo return NOTIFY_OK; 364865758202STejun Heo } 364965758202STejun Heo 365065758202STejun Heo /* 365165758202STejun Heo * Workqueues should be brought down after normal priority CPU notifiers. 365265758202STejun Heo * This will be registered as low priority CPU notifier. 365365758202STejun Heo */ 365465758202STejun Heo static int __devinit workqueue_cpu_down_callback(struct notifier_block *nfb, 365565758202STejun Heo unsigned long action, 365665758202STejun Heo void *hcpu) 365765758202STejun Heo { 36588db25e78STejun Heo unsigned int cpu = (unsigned long)hcpu; 36598db25e78STejun Heo struct work_struct unbind_work; 36608db25e78STejun Heo 366165758202STejun Heo switch (action & ~CPU_TASKS_FROZEN) { 366265758202STejun Heo case CPU_DOWN_PREPARE: 36638db25e78STejun Heo /* unbinding should happen on the local CPU */ 36648db25e78STejun Heo INIT_WORK_ONSTACK(&unbind_work, gcwq_unbind_fn); 36658db25e78STejun Heo schedule_work_on(cpu, &unbind_work); 36668db25e78STejun Heo flush_work(&unbind_work); 36678db25e78STejun Heo break; 366865758202STejun Heo } 366965758202STejun Heo return NOTIFY_OK; 367065758202STejun Heo } 367165758202STejun Heo 36722d3854a3SRusty Russell #ifdef CONFIG_SMP 36738ccad40dSRusty Russell 36742d3854a3SRusty Russell struct work_for_cpu { 36756b44003eSAndrew Morton struct completion completion; 36762d3854a3SRusty Russell long (*fn)(void *); 36772d3854a3SRusty Russell void *arg; 36782d3854a3SRusty Russell long ret; 36792d3854a3SRusty Russell }; 36802d3854a3SRusty Russell 36816b44003eSAndrew Morton static int do_work_for_cpu(void *_wfc) 36822d3854a3SRusty Russell { 36836b44003eSAndrew Morton struct work_for_cpu *wfc = _wfc; 36842d3854a3SRusty Russell wfc->ret = wfc->fn(wfc->arg); 36856b44003eSAndrew Morton complete(&wfc->completion); 36866b44003eSAndrew Morton return 0; 36872d3854a3SRusty Russell } 36882d3854a3SRusty Russell 36892d3854a3SRusty Russell /** 36902d3854a3SRusty Russell * work_on_cpu - run a function in user context on a particular cpu 36912d3854a3SRusty Russell * @cpu: the cpu to run on 36922d3854a3SRusty Russell * @fn: the function to run 36932d3854a3SRusty Russell * @arg: the function arg 36942d3854a3SRusty Russell * 369531ad9081SRusty Russell * This will return the value @fn returns. 369631ad9081SRusty Russell * It is up to the caller to ensure that the cpu doesn't go offline. 36976b44003eSAndrew Morton * The caller must not hold any locks which would prevent @fn from completing. 36982d3854a3SRusty Russell */ 36992d3854a3SRusty Russell long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg) 37002d3854a3SRusty Russell { 37016b44003eSAndrew Morton struct task_struct *sub_thread; 37026b44003eSAndrew Morton struct work_for_cpu wfc = { 37036b44003eSAndrew Morton .completion = COMPLETION_INITIALIZER_ONSTACK(wfc.completion), 37046b44003eSAndrew Morton .fn = fn, 37056b44003eSAndrew Morton .arg = arg, 37066b44003eSAndrew Morton }; 37072d3854a3SRusty Russell 37086b44003eSAndrew Morton sub_thread = kthread_create(do_work_for_cpu, &wfc, "work_for_cpu"); 37096b44003eSAndrew Morton if (IS_ERR(sub_thread)) 37106b44003eSAndrew Morton return PTR_ERR(sub_thread); 37116b44003eSAndrew Morton kthread_bind(sub_thread, cpu); 37126b44003eSAndrew Morton wake_up_process(sub_thread); 37136b44003eSAndrew Morton wait_for_completion(&wfc.completion); 37142d3854a3SRusty Russell return wfc.ret; 37152d3854a3SRusty Russell } 37162d3854a3SRusty Russell EXPORT_SYMBOL_GPL(work_on_cpu); 37172d3854a3SRusty Russell #endif /* CONFIG_SMP */ 37182d3854a3SRusty Russell 3719a0a1a5fdSTejun Heo #ifdef CONFIG_FREEZER 3720e7577c50SRusty Russell 3721a0a1a5fdSTejun Heo /** 3722a0a1a5fdSTejun Heo * freeze_workqueues_begin - begin freezing workqueues 3723a0a1a5fdSTejun Heo * 372458a69cb4STejun Heo * Start freezing workqueues. After this function returns, all freezable 372558a69cb4STejun Heo * workqueues will queue new works to their frozen_works list instead of 372658a69cb4STejun Heo * gcwq->worklist. 3727a0a1a5fdSTejun Heo * 3728a0a1a5fdSTejun Heo * CONTEXT: 37298b03ae3cSTejun Heo * Grabs and releases workqueue_lock and gcwq->lock's. 3730a0a1a5fdSTejun Heo */ 3731a0a1a5fdSTejun Heo void freeze_workqueues_begin(void) 3732a0a1a5fdSTejun Heo { 3733a0a1a5fdSTejun Heo unsigned int cpu; 3734a0a1a5fdSTejun Heo 3735a0a1a5fdSTejun Heo spin_lock(&workqueue_lock); 3736a0a1a5fdSTejun Heo 3737a0a1a5fdSTejun Heo BUG_ON(workqueue_freezing); 3738a0a1a5fdSTejun Heo workqueue_freezing = true; 3739a0a1a5fdSTejun Heo 3740f3421797STejun Heo for_each_gcwq_cpu(cpu) { 37418b03ae3cSTejun Heo struct global_cwq *gcwq = get_gcwq(cpu); 3742bdbc5dd7STejun Heo struct workqueue_struct *wq; 37438b03ae3cSTejun Heo 37448b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 37458b03ae3cSTejun Heo 3746db7bccf4STejun Heo BUG_ON(gcwq->flags & GCWQ_FREEZING); 3747db7bccf4STejun Heo gcwq->flags |= GCWQ_FREEZING; 3748db7bccf4STejun Heo 3749a0a1a5fdSTejun Heo list_for_each_entry(wq, &workqueues, list) { 3750a0a1a5fdSTejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 3751a0a1a5fdSTejun Heo 375258a69cb4STejun Heo if (cwq && wq->flags & WQ_FREEZABLE) 3753a0a1a5fdSTejun Heo cwq->max_active = 0; 37541da177e4SLinus Torvalds } 37558b03ae3cSTejun Heo 37568b03ae3cSTejun Heo spin_unlock_irq(&gcwq->lock); 3757a0a1a5fdSTejun Heo } 3758a0a1a5fdSTejun Heo 3759a0a1a5fdSTejun Heo spin_unlock(&workqueue_lock); 3760a0a1a5fdSTejun Heo } 3761a0a1a5fdSTejun Heo 3762a0a1a5fdSTejun Heo /** 376358a69cb4STejun Heo * freeze_workqueues_busy - are freezable workqueues still busy? 3764a0a1a5fdSTejun Heo * 3765a0a1a5fdSTejun Heo * Check whether freezing is complete. This function must be called 3766a0a1a5fdSTejun Heo * between freeze_workqueues_begin() and thaw_workqueues(). 3767a0a1a5fdSTejun Heo * 3768a0a1a5fdSTejun Heo * CONTEXT: 3769a0a1a5fdSTejun Heo * Grabs and releases workqueue_lock. 3770a0a1a5fdSTejun Heo * 3771a0a1a5fdSTejun Heo * RETURNS: 377258a69cb4STejun Heo * %true if some freezable workqueues are still busy. %false if freezing 377358a69cb4STejun Heo * is complete. 3774a0a1a5fdSTejun Heo */ 3775a0a1a5fdSTejun Heo bool freeze_workqueues_busy(void) 3776a0a1a5fdSTejun Heo { 3777a0a1a5fdSTejun Heo unsigned int cpu; 3778a0a1a5fdSTejun Heo bool busy = false; 3779a0a1a5fdSTejun Heo 3780a0a1a5fdSTejun Heo spin_lock(&workqueue_lock); 3781a0a1a5fdSTejun Heo 3782a0a1a5fdSTejun Heo BUG_ON(!workqueue_freezing); 3783a0a1a5fdSTejun Heo 3784f3421797STejun Heo for_each_gcwq_cpu(cpu) { 3785bdbc5dd7STejun Heo struct workqueue_struct *wq; 3786a0a1a5fdSTejun Heo /* 3787a0a1a5fdSTejun Heo * nr_active is monotonically decreasing. It's safe 3788a0a1a5fdSTejun Heo * to peek without lock. 3789a0a1a5fdSTejun Heo */ 3790a0a1a5fdSTejun Heo list_for_each_entry(wq, &workqueues, list) { 3791a0a1a5fdSTejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 3792a0a1a5fdSTejun Heo 379358a69cb4STejun Heo if (!cwq || !(wq->flags & WQ_FREEZABLE)) 3794a0a1a5fdSTejun Heo continue; 3795a0a1a5fdSTejun Heo 3796a0a1a5fdSTejun Heo BUG_ON(cwq->nr_active < 0); 3797a0a1a5fdSTejun Heo if (cwq->nr_active) { 3798a0a1a5fdSTejun Heo busy = true; 3799a0a1a5fdSTejun Heo goto out_unlock; 3800a0a1a5fdSTejun Heo } 3801a0a1a5fdSTejun Heo } 3802a0a1a5fdSTejun Heo } 3803a0a1a5fdSTejun Heo out_unlock: 3804a0a1a5fdSTejun Heo spin_unlock(&workqueue_lock); 3805a0a1a5fdSTejun Heo return busy; 3806a0a1a5fdSTejun Heo } 3807a0a1a5fdSTejun Heo 3808a0a1a5fdSTejun Heo /** 3809a0a1a5fdSTejun Heo * thaw_workqueues - thaw workqueues 3810a0a1a5fdSTejun Heo * 3811a0a1a5fdSTejun Heo * Thaw workqueues. Normal queueing is restored and all collected 38127e11629dSTejun Heo * frozen works are transferred to their respective gcwq worklists. 3813a0a1a5fdSTejun Heo * 3814a0a1a5fdSTejun Heo * CONTEXT: 38158b03ae3cSTejun Heo * Grabs and releases workqueue_lock and gcwq->lock's. 3816a0a1a5fdSTejun Heo */ 3817a0a1a5fdSTejun Heo void thaw_workqueues(void) 3818a0a1a5fdSTejun Heo { 3819a0a1a5fdSTejun Heo unsigned int cpu; 3820a0a1a5fdSTejun Heo 3821a0a1a5fdSTejun Heo spin_lock(&workqueue_lock); 3822a0a1a5fdSTejun Heo 3823a0a1a5fdSTejun Heo if (!workqueue_freezing) 3824a0a1a5fdSTejun Heo goto out_unlock; 3825a0a1a5fdSTejun Heo 3826f3421797STejun Heo for_each_gcwq_cpu(cpu) { 38278b03ae3cSTejun Heo struct global_cwq *gcwq = get_gcwq(cpu); 38284ce62e9eSTejun Heo struct worker_pool *pool; 3829bdbc5dd7STejun Heo struct workqueue_struct *wq; 38308b03ae3cSTejun Heo 38318b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 38328b03ae3cSTejun Heo 3833db7bccf4STejun Heo BUG_ON(!(gcwq->flags & GCWQ_FREEZING)); 3834db7bccf4STejun Heo gcwq->flags &= ~GCWQ_FREEZING; 3835db7bccf4STejun Heo 3836a0a1a5fdSTejun Heo list_for_each_entry(wq, &workqueues, list) { 3837a0a1a5fdSTejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 3838a0a1a5fdSTejun Heo 383958a69cb4STejun Heo if (!cwq || !(wq->flags & WQ_FREEZABLE)) 3840a0a1a5fdSTejun Heo continue; 3841a0a1a5fdSTejun Heo 3842a0a1a5fdSTejun Heo /* restore max_active and repopulate worklist */ 3843a0a1a5fdSTejun Heo cwq->max_active = wq->saved_max_active; 3844a0a1a5fdSTejun Heo 3845a0a1a5fdSTejun Heo while (!list_empty(&cwq->delayed_works) && 3846a0a1a5fdSTejun Heo cwq->nr_active < cwq->max_active) 3847a0a1a5fdSTejun Heo cwq_activate_first_delayed(cwq); 3848a0a1a5fdSTejun Heo } 38498b03ae3cSTejun Heo 38504ce62e9eSTejun Heo for_each_worker_pool(pool, gcwq) 38514ce62e9eSTejun Heo wake_up_worker(pool); 3852e22bee78STejun Heo 38538b03ae3cSTejun Heo spin_unlock_irq(&gcwq->lock); 3854a0a1a5fdSTejun Heo } 3855a0a1a5fdSTejun Heo 3856a0a1a5fdSTejun Heo workqueue_freezing = false; 3857a0a1a5fdSTejun Heo out_unlock: 3858a0a1a5fdSTejun Heo spin_unlock(&workqueue_lock); 3859a0a1a5fdSTejun Heo } 3860a0a1a5fdSTejun Heo #endif /* CONFIG_FREEZER */ 3861a0a1a5fdSTejun Heo 38626ee0578bSSuresh Siddha static int __init init_workqueues(void) 38631da177e4SLinus Torvalds { 3864c34056a3STejun Heo unsigned int cpu; 3865c8e55f36STejun Heo int i; 3866c34056a3STejun Heo 3867b5490077STejun Heo /* make sure we have enough bits for OFFQ CPU number */ 3868b5490077STejun Heo BUILD_BUG_ON((1LU << (BITS_PER_LONG - WORK_OFFQ_CPU_SHIFT)) < 3869b5490077STejun Heo WORK_CPU_LAST); 3870b5490077STejun Heo 387165758202STejun Heo cpu_notifier(workqueue_cpu_up_callback, CPU_PRI_WORKQUEUE_UP); 387265758202STejun Heo cpu_notifier(workqueue_cpu_down_callback, CPU_PRI_WORKQUEUE_DOWN); 38738b03ae3cSTejun Heo 38748b03ae3cSTejun Heo /* initialize gcwqs */ 3875f3421797STejun Heo for_each_gcwq_cpu(cpu) { 38768b03ae3cSTejun Heo struct global_cwq *gcwq = get_gcwq(cpu); 38774ce62e9eSTejun Heo struct worker_pool *pool; 38788b03ae3cSTejun Heo 38798b03ae3cSTejun Heo spin_lock_init(&gcwq->lock); 38808b03ae3cSTejun Heo gcwq->cpu = cpu; 3881f3421797STejun Heo gcwq->flags |= GCWQ_DISASSOCIATED; 38828b03ae3cSTejun Heo 3883c8e55f36STejun Heo for (i = 0; i < BUSY_WORKER_HASH_SIZE; i++) 3884c8e55f36STejun Heo INIT_HLIST_HEAD(&gcwq->busy_hash[i]); 3885c8e55f36STejun Heo 38864ce62e9eSTejun Heo for_each_worker_pool(pool, gcwq) { 38874ce62e9eSTejun Heo pool->gcwq = gcwq; 38884ce62e9eSTejun Heo INIT_LIST_HEAD(&pool->worklist); 38894ce62e9eSTejun Heo INIT_LIST_HEAD(&pool->idle_list); 3890e22bee78STejun Heo 38914ce62e9eSTejun Heo init_timer_deferrable(&pool->idle_timer); 38924ce62e9eSTejun Heo pool->idle_timer.function = idle_worker_timeout; 38934ce62e9eSTejun Heo pool->idle_timer.data = (unsigned long)pool; 3894e22bee78STejun Heo 38954ce62e9eSTejun Heo setup_timer(&pool->mayday_timer, gcwq_mayday_timeout, 38964ce62e9eSTejun Heo (unsigned long)pool); 38974ce62e9eSTejun Heo 389860373152STejun Heo mutex_init(&pool->manager_mutex); 38994ce62e9eSTejun Heo ida_init(&pool->worker_ida); 39004ce62e9eSTejun Heo } 3901db7bccf4STejun Heo 390225511a47STejun Heo init_waitqueue_head(&gcwq->rebind_hold); 39038b03ae3cSTejun Heo } 39048b03ae3cSTejun Heo 3905e22bee78STejun Heo /* create the initial worker */ 3906f3421797STejun Heo for_each_online_gcwq_cpu(cpu) { 3907e22bee78STejun Heo struct global_cwq *gcwq = get_gcwq(cpu); 39084ce62e9eSTejun Heo struct worker_pool *pool; 3909e22bee78STejun Heo 3910477a3c33STejun Heo if (cpu != WORK_CPU_UNBOUND) 3911477a3c33STejun Heo gcwq->flags &= ~GCWQ_DISASSOCIATED; 39124ce62e9eSTejun Heo 39134ce62e9eSTejun Heo for_each_worker_pool(pool, gcwq) { 39144ce62e9eSTejun Heo struct worker *worker; 39154ce62e9eSTejun Heo 3916bc2ae0f5STejun Heo worker = create_worker(pool); 3917e22bee78STejun Heo BUG_ON(!worker); 3918e22bee78STejun Heo spin_lock_irq(&gcwq->lock); 3919e22bee78STejun Heo start_worker(worker); 3920e22bee78STejun Heo spin_unlock_irq(&gcwq->lock); 3921e22bee78STejun Heo } 39224ce62e9eSTejun Heo } 3923e22bee78STejun Heo 3924d320c038STejun Heo system_wq = alloc_workqueue("events", 0, 0); 3925d320c038STejun Heo system_long_wq = alloc_workqueue("events_long", 0, 0); 3926d320c038STejun Heo system_nrt_wq = alloc_workqueue("events_nrt", WQ_NON_REENTRANT, 0); 3927f3421797STejun Heo system_unbound_wq = alloc_workqueue("events_unbound", WQ_UNBOUND, 3928f3421797STejun Heo WQ_UNBOUND_MAX_ACTIVE); 392924d51addSTejun Heo system_freezable_wq = alloc_workqueue("events_freezable", 393024d51addSTejun Heo WQ_FREEZABLE, 0); 393162d3c543SAlan Stern system_nrt_freezable_wq = alloc_workqueue("events_nrt_freezable", 393262d3c543SAlan Stern WQ_NON_REENTRANT | WQ_FREEZABLE, 0); 3933e5cba24eSHitoshi Mitake BUG_ON(!system_wq || !system_long_wq || !system_nrt_wq || 393462d3c543SAlan Stern !system_unbound_wq || !system_freezable_wq || 393562d3c543SAlan Stern !system_nrt_freezable_wq); 39366ee0578bSSuresh Siddha return 0; 39371da177e4SLinus Torvalds } 39386ee0578bSSuresh Siddha early_initcall(init_workqueues); 3939