11da177e4SLinus Torvalds /* 2c54fce6eSTejun Heo * kernel/workqueue.c - generic async execution with shared worker pool 31da177e4SLinus Torvalds * 4c54fce6eSTejun Heo * Copyright (C) 2002 Ingo Molnar 51da177e4SLinus Torvalds * 61da177e4SLinus Torvalds * Derived from the taskqueue/keventd code by: 71da177e4SLinus Torvalds * David Woodhouse <dwmw2@infradead.org> 8e1f8e874SFrancois Cami * Andrew Morton 91da177e4SLinus Torvalds * Kai Petzke <wpp@marie.physik.tu-berlin.de> 101da177e4SLinus Torvalds * Theodore Ts'o <tytso@mit.edu> 1189ada679SChristoph Lameter * 12cde53535SChristoph Lameter * Made to use alloc_percpu by Christoph Lameter. 13c54fce6eSTejun Heo * 14c54fce6eSTejun Heo * Copyright (C) 2010 SUSE Linux Products GmbH 15c54fce6eSTejun Heo * Copyright (C) 2010 Tejun Heo <tj@kernel.org> 16c54fce6eSTejun Heo * 17c54fce6eSTejun Heo * This is the generic async execution mechanism. Work items as are 18c54fce6eSTejun Heo * executed in process context. The worker pool is shared and 19c54fce6eSTejun Heo * automatically managed. There is one worker pool for each CPU and 20c54fce6eSTejun Heo * one extra for works which are better served by workers which are 21c54fce6eSTejun Heo * not bound to any specific CPU. 22c54fce6eSTejun Heo * 23c54fce6eSTejun Heo * Please read Documentation/workqueue.txt for details. 241da177e4SLinus Torvalds */ 251da177e4SLinus Torvalds 269984de1aSPaul Gortmaker #include <linux/export.h> 271da177e4SLinus Torvalds #include <linux/kernel.h> 281da177e4SLinus Torvalds #include <linux/sched.h> 291da177e4SLinus Torvalds #include <linux/init.h> 301da177e4SLinus Torvalds #include <linux/signal.h> 311da177e4SLinus Torvalds #include <linux/completion.h> 321da177e4SLinus Torvalds #include <linux/workqueue.h> 331da177e4SLinus Torvalds #include <linux/slab.h> 341da177e4SLinus Torvalds #include <linux/cpu.h> 351da177e4SLinus Torvalds #include <linux/notifier.h> 361da177e4SLinus Torvalds #include <linux/kthread.h> 371fa44ecaSJames Bottomley #include <linux/hardirq.h> 3846934023SChristoph Lameter #include <linux/mempolicy.h> 39341a5958SRafael J. Wysocki #include <linux/freezer.h> 40d5abe669SPeter Zijlstra #include <linux/kallsyms.h> 41d5abe669SPeter Zijlstra #include <linux/debug_locks.h> 424e6045f1SJohannes Berg #include <linux/lockdep.h> 43c34056a3STejun Heo #include <linux/idr.h> 4442f8570fSSasha Levin #include <linux/hashtable.h> 45e22bee78STejun Heo 46ea138446STejun Heo #include "workqueue_internal.h" 471da177e4SLinus Torvalds 48c8e55f36STejun Heo enum { 49bc2ae0f5STejun Heo /* 5024647570STejun Heo * worker_pool flags 51bc2ae0f5STejun Heo * 5224647570STejun Heo * A bound pool is either associated or disassociated with its CPU. 53bc2ae0f5STejun Heo * While associated (!DISASSOCIATED), all workers are bound to the 54bc2ae0f5STejun Heo * CPU and none has %WORKER_UNBOUND set and concurrency management 55bc2ae0f5STejun Heo * is in effect. 56bc2ae0f5STejun Heo * 57bc2ae0f5STejun Heo * While DISASSOCIATED, the cpu may be offline and all workers have 58bc2ae0f5STejun Heo * %WORKER_UNBOUND set and concurrency management disabled, and may 5924647570STejun Heo * be executing on any CPU. The pool behaves as an unbound one. 60bc2ae0f5STejun Heo * 61bc2ae0f5STejun Heo * Note that DISASSOCIATED can be flipped only while holding 6224647570STejun Heo * assoc_mutex to avoid changing binding state while 6324647570STejun Heo * create_worker() is in progress. 64bc2ae0f5STejun Heo */ 6511ebea50STejun Heo POOL_MANAGE_WORKERS = 1 << 0, /* need to manage workers */ 66552a37e9SLai Jiangshan POOL_MANAGING_WORKERS = 1 << 1, /* managing workers */ 6724647570STejun Heo POOL_DISASSOCIATED = 1 << 2, /* cpu can't serve workers */ 6835b6bb63STejun Heo POOL_FREEZING = 1 << 3, /* freeze in progress */ 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 */ 75fb0e7bebSTejun Heo WORKER_CPU_INTENSIVE = 1 << 6, /* cpu intensive */ 76f3421797STejun Heo WORKER_UNBOUND = 1 << 7, /* worker is unbound */ 77e22bee78STejun Heo 785f7dabfdSLai Jiangshan WORKER_NOT_RUNNING = WORKER_PREP | WORKER_UNBOUND | 79403c821dSTejun Heo WORKER_CPU_INTENSIVE, 80db7bccf4STejun Heo 81e34cdddbSTejun Heo NR_STD_WORKER_POOLS = 2, /* # standard pools per cpu */ 824ce62e9eSTejun Heo 83c8e55f36STejun Heo BUSY_WORKER_HASH_ORDER = 6, /* 64 pointers */ 84db7bccf4STejun Heo 85e22bee78STejun Heo MAX_IDLE_WORKERS_RATIO = 4, /* 1/4 of busy can be idle */ 86e22bee78STejun Heo IDLE_WORKER_TIMEOUT = 300 * HZ, /* keep idle ones for 5 mins */ 87e22bee78STejun Heo 883233cdbdSTejun Heo MAYDAY_INITIAL_TIMEOUT = HZ / 100 >= 2 ? HZ / 100 : 2, 893233cdbdSTejun Heo /* call for help after 10ms 903233cdbdSTejun Heo (min two ticks) */ 91e22bee78STejun Heo MAYDAY_INTERVAL = HZ / 10, /* and then every 100ms */ 92e22bee78STejun Heo CREATE_COOLDOWN = HZ, /* time to breath after fail */ 931da177e4SLinus Torvalds 941da177e4SLinus Torvalds /* 95e22bee78STejun Heo * Rescue workers are used only on emergencies and shared by 96e22bee78STejun Heo * all cpus. Give -20. 97e22bee78STejun Heo */ 98e22bee78STejun Heo RESCUER_NICE_LEVEL = -20, 993270476aSTejun Heo HIGHPRI_NICE_LEVEL = -20, 100c8e55f36STejun Heo }; 101c8e55f36STejun Heo 1021da177e4SLinus Torvalds /* 1034690c4abSTejun Heo * Structure fields follow one of the following exclusion rules. 1044690c4abSTejun Heo * 105e41e704bSTejun Heo * I: Modifiable by initialization/destruction paths and read-only for 106e41e704bSTejun Heo * everyone else. 1074690c4abSTejun Heo * 108e22bee78STejun Heo * P: Preemption protected. Disabling preemption is enough and should 109e22bee78STejun Heo * only be modified and accessed from the local cpu. 110e22bee78STejun Heo * 1118b03ae3cSTejun Heo * L: gcwq->lock protected. Access with gcwq->lock held. 1124690c4abSTejun Heo * 113e22bee78STejun Heo * X: During normal operation, modification requires gcwq->lock and 114e22bee78STejun Heo * should be done only from local cpu. Either disabling preemption 115e22bee78STejun Heo * on local cpu or grabbing gcwq->lock is enough for read access. 11624647570STejun Heo * If POOL_DISASSOCIATED is set, it's identical to L. 117e22bee78STejun Heo * 11873f53c4aSTejun Heo * F: wq->flush_mutex protected. 11973f53c4aSTejun Heo * 1204690c4abSTejun Heo * W: workqueue_lock protected. 1214690c4abSTejun Heo */ 1224690c4abSTejun Heo 1232eaebdb3STejun Heo /* struct worker is defined in workqueue_internal.h */ 124c34056a3STejun Heo 125bd7bdd43STejun Heo struct worker_pool { 126bd7bdd43STejun Heo struct global_cwq *gcwq; /* I: the owning gcwq */ 127ec22ca5eSTejun Heo unsigned int cpu; /* I: the associated cpu */ 1289daf9e67STejun Heo int id; /* I: pool ID */ 12911ebea50STejun Heo unsigned int flags; /* X: flags */ 130bd7bdd43STejun Heo 131bd7bdd43STejun Heo struct list_head worklist; /* L: list of pending works */ 132bd7bdd43STejun Heo int nr_workers; /* L: total number of workers */ 133ea1abd61SLai Jiangshan 134ea1abd61SLai Jiangshan /* nr_idle includes the ones off idle_list for rebinding */ 135bd7bdd43STejun Heo int nr_idle; /* L: currently idle ones */ 136bd7bdd43STejun Heo 137bd7bdd43STejun Heo struct list_head idle_list; /* X: list of idle workers */ 138bd7bdd43STejun Heo struct timer_list idle_timer; /* L: worker idle timeout */ 139bd7bdd43STejun Heo struct timer_list mayday_timer; /* L: SOS timer for workers */ 140bd7bdd43STejun Heo 141c9e7cf27STejun Heo /* workers are chained either in busy_hash or idle_list */ 142c9e7cf27STejun Heo DECLARE_HASHTABLE(busy_hash, BUSY_WORKER_HASH_ORDER); 143c9e7cf27STejun Heo /* L: hash of busy workers */ 144c9e7cf27STejun Heo 14524647570STejun Heo struct mutex assoc_mutex; /* protect POOL_DISASSOCIATED */ 146bd7bdd43STejun Heo struct ida worker_ida; /* L: for worker IDs */ 147bd7bdd43STejun Heo }; 148bd7bdd43STejun Heo 1494690c4abSTejun Heo /* 150e22bee78STejun Heo * Global per-cpu workqueue. There's one and only one for each cpu 151e22bee78STejun Heo * and all works are queued and processed here regardless of their 152e22bee78STejun Heo * target workqueues. 1538b03ae3cSTejun Heo */ 1548b03ae3cSTejun Heo struct global_cwq { 1558b03ae3cSTejun Heo spinlock_t lock; /* the gcwq lock */ 156c8e55f36STejun Heo 157e34cdddbSTejun Heo struct worker_pool pools[NR_STD_WORKER_POOLS]; 158330dad5bSJoonsoo Kim /* normal and highpri pools */ 1598b03ae3cSTejun Heo } ____cacheline_aligned_in_smp; 1608b03ae3cSTejun Heo 1618b03ae3cSTejun Heo /* 162502ca9d8STejun Heo * The per-CPU workqueue. The lower WORK_STRUCT_FLAG_BITS of 1630f900049STejun Heo * work_struct->data are used for flags and thus cwqs need to be 1640f900049STejun Heo * aligned at two's power of the number of flag bits. 1651da177e4SLinus Torvalds */ 1661da177e4SLinus Torvalds struct cpu_workqueue_struct { 167bd7bdd43STejun Heo struct worker_pool *pool; /* I: the associated pool */ 1684690c4abSTejun Heo struct workqueue_struct *wq; /* I: the owning workqueue */ 16973f53c4aSTejun Heo int work_color; /* L: current color */ 17073f53c4aSTejun Heo int flush_color; /* L: flushing color */ 17173f53c4aSTejun Heo int nr_in_flight[WORK_NR_COLORS]; 17273f53c4aSTejun Heo /* L: nr of in_flight works */ 1731e19ffc6STejun Heo int nr_active; /* L: nr of active works */ 174a0a1a5fdSTejun Heo int max_active; /* L: max active works */ 1751e19ffc6STejun Heo struct list_head delayed_works; /* L: delayed works */ 1760f900049STejun Heo }; 1771da177e4SLinus Torvalds 1781da177e4SLinus Torvalds /* 17973f53c4aSTejun Heo * Structure used to wait for workqueue flush. 18073f53c4aSTejun Heo */ 18173f53c4aSTejun Heo struct wq_flusher { 18273f53c4aSTejun Heo struct list_head list; /* F: list of flushers */ 18373f53c4aSTejun Heo int flush_color; /* F: flush color waiting for */ 18473f53c4aSTejun Heo struct completion done; /* flush completion */ 18573f53c4aSTejun Heo }; 1861da177e4SLinus Torvalds 18773f53c4aSTejun Heo /* 188f2e005aaSTejun Heo * All cpumasks are assumed to be always set on UP and thus can't be 189f2e005aaSTejun Heo * used to determine whether there's something to be done. 190f2e005aaSTejun Heo */ 191f2e005aaSTejun Heo #ifdef CONFIG_SMP 192f2e005aaSTejun Heo typedef cpumask_var_t mayday_mask_t; 193f2e005aaSTejun Heo #define mayday_test_and_set_cpu(cpu, mask) \ 194f2e005aaSTejun Heo cpumask_test_and_set_cpu((cpu), (mask)) 195f2e005aaSTejun Heo #define mayday_clear_cpu(cpu, mask) cpumask_clear_cpu((cpu), (mask)) 196f2e005aaSTejun Heo #define for_each_mayday_cpu(cpu, mask) for_each_cpu((cpu), (mask)) 1979c37547aSTejun Heo #define alloc_mayday_mask(maskp, gfp) zalloc_cpumask_var((maskp), (gfp)) 198f2e005aaSTejun Heo #define free_mayday_mask(mask) free_cpumask_var((mask)) 199f2e005aaSTejun Heo #else 200f2e005aaSTejun Heo typedef unsigned long mayday_mask_t; 201f2e005aaSTejun Heo #define mayday_test_and_set_cpu(cpu, mask) test_and_set_bit(0, &(mask)) 202f2e005aaSTejun Heo #define mayday_clear_cpu(cpu, mask) clear_bit(0, &(mask)) 203f2e005aaSTejun Heo #define for_each_mayday_cpu(cpu, mask) if ((cpu) = 0, (mask)) 204f2e005aaSTejun Heo #define alloc_mayday_mask(maskp, gfp) true 205f2e005aaSTejun Heo #define free_mayday_mask(mask) do { } while (0) 206f2e005aaSTejun Heo #endif 2071da177e4SLinus Torvalds 2081da177e4SLinus Torvalds /* 2091da177e4SLinus Torvalds * The externally visible workqueue abstraction is an array of 2101da177e4SLinus Torvalds * per-CPU workqueues: 2111da177e4SLinus Torvalds */ 2121da177e4SLinus Torvalds struct workqueue_struct { 2139c5a2ba7STejun Heo unsigned int flags; /* W: WQ_* flags */ 214bdbc5dd7STejun Heo union { 215bdbc5dd7STejun Heo struct cpu_workqueue_struct __percpu *pcpu; 216bdbc5dd7STejun Heo struct cpu_workqueue_struct *single; 217bdbc5dd7STejun Heo unsigned long v; 218bdbc5dd7STejun Heo } cpu_wq; /* I: cwq's */ 2194690c4abSTejun Heo struct list_head list; /* W: list of all workqueues */ 22073f53c4aSTejun Heo 22173f53c4aSTejun Heo struct mutex flush_mutex; /* protects wq flushing */ 22273f53c4aSTejun Heo int work_color; /* F: current work color */ 22373f53c4aSTejun Heo int flush_color; /* F: current flush color */ 22473f53c4aSTejun Heo atomic_t nr_cwqs_to_flush; /* flush in progress */ 22573f53c4aSTejun Heo struct wq_flusher *first_flusher; /* F: first flusher */ 22673f53c4aSTejun Heo struct list_head flusher_queue; /* F: flush waiters */ 22773f53c4aSTejun Heo struct list_head flusher_overflow; /* F: flush overflow list */ 22873f53c4aSTejun Heo 229f2e005aaSTejun Heo mayday_mask_t mayday_mask; /* cpus requesting rescue */ 230e22bee78STejun Heo struct worker *rescuer; /* I: rescue worker */ 231e22bee78STejun Heo 2329c5a2ba7STejun Heo int nr_drainers; /* W: drain in progress */ 233dcd989cbSTejun Heo int saved_max_active; /* W: saved cwq max_active */ 2344e6045f1SJohannes Berg #ifdef CONFIG_LOCKDEP 2354e6045f1SJohannes Berg struct lockdep_map lockdep_map; 2364e6045f1SJohannes Berg #endif 237b196be89STejun Heo char name[]; /* I: workqueue name */ 2381da177e4SLinus Torvalds }; 2391da177e4SLinus Torvalds 240d320c038STejun Heo struct workqueue_struct *system_wq __read_mostly; 241d320c038STejun Heo EXPORT_SYMBOL_GPL(system_wq); 242044c782cSValentin Ilie struct workqueue_struct *system_highpri_wq __read_mostly; 2431aabe902SJoonsoo Kim EXPORT_SYMBOL_GPL(system_highpri_wq); 244044c782cSValentin Ilie struct workqueue_struct *system_long_wq __read_mostly; 245d320c038STejun Heo EXPORT_SYMBOL_GPL(system_long_wq); 246044c782cSValentin Ilie struct workqueue_struct *system_unbound_wq __read_mostly; 247f3421797STejun Heo EXPORT_SYMBOL_GPL(system_unbound_wq); 248044c782cSValentin Ilie struct workqueue_struct *system_freezable_wq __read_mostly; 24924d51addSTejun Heo EXPORT_SYMBOL_GPL(system_freezable_wq); 250d320c038STejun Heo 25197bd2347STejun Heo #define CREATE_TRACE_POINTS 25297bd2347STejun Heo #include <trace/events/workqueue.h> 25397bd2347STejun Heo 2544ce62e9eSTejun Heo #define for_each_worker_pool(pool, gcwq) \ 2553270476aSTejun Heo for ((pool) = &(gcwq)->pools[0]; \ 256e34cdddbSTejun Heo (pool) < &(gcwq)->pools[NR_STD_WORKER_POOLS]; (pool)++) 2574ce62e9eSTejun Heo 258c9e7cf27STejun Heo #define for_each_busy_worker(worker, i, pos, pool) \ 259c9e7cf27STejun Heo hash_for_each(pool->busy_hash, i, pos, worker, hentry) 260db7bccf4STejun Heo 261f3421797STejun Heo static inline int __next_gcwq_cpu(int cpu, const struct cpumask *mask, 262f3421797STejun Heo unsigned int sw) 263f3421797STejun Heo { 264f3421797STejun Heo if (cpu < nr_cpu_ids) { 265f3421797STejun Heo if (sw & 1) { 266f3421797STejun Heo cpu = cpumask_next(cpu, mask); 267f3421797STejun Heo if (cpu < nr_cpu_ids) 268f3421797STejun Heo return cpu; 269f3421797STejun Heo } 270f3421797STejun Heo if (sw & 2) 271f3421797STejun Heo return WORK_CPU_UNBOUND; 272f3421797STejun Heo } 273f3421797STejun Heo return WORK_CPU_NONE; 274f3421797STejun Heo } 275f3421797STejun Heo 276f3421797STejun Heo static inline int __next_wq_cpu(int cpu, const struct cpumask *mask, 277f3421797STejun Heo struct workqueue_struct *wq) 278f3421797STejun Heo { 279f3421797STejun Heo return __next_gcwq_cpu(cpu, mask, !(wq->flags & WQ_UNBOUND) ? 1 : 2); 280f3421797STejun Heo } 281f3421797STejun Heo 28209884951STejun Heo /* 28309884951STejun Heo * CPU iterators 28409884951STejun Heo * 28509884951STejun Heo * An extra gcwq is defined for an invalid cpu number 28609884951STejun Heo * (WORK_CPU_UNBOUND) to host workqueues which are not bound to any 28709884951STejun Heo * specific CPU. The following iterators are similar to 28809884951STejun Heo * for_each_*_cpu() iterators but also considers the unbound gcwq. 28909884951STejun Heo * 29009884951STejun Heo * for_each_gcwq_cpu() : possible CPUs + WORK_CPU_UNBOUND 29109884951STejun Heo * for_each_online_gcwq_cpu() : online CPUs + WORK_CPU_UNBOUND 29209884951STejun Heo * for_each_cwq_cpu() : possible CPUs for bound workqueues, 29309884951STejun Heo * WORK_CPU_UNBOUND for unbound workqueues 29409884951STejun Heo */ 295f3421797STejun Heo #define for_each_gcwq_cpu(cpu) \ 296f3421797STejun Heo for ((cpu) = __next_gcwq_cpu(-1, cpu_possible_mask, 3); \ 297f3421797STejun Heo (cpu) < WORK_CPU_NONE; \ 298f3421797STejun Heo (cpu) = __next_gcwq_cpu((cpu), cpu_possible_mask, 3)) 299f3421797STejun Heo 300f3421797STejun Heo #define for_each_online_gcwq_cpu(cpu) \ 301f3421797STejun Heo for ((cpu) = __next_gcwq_cpu(-1, cpu_online_mask, 3); \ 302f3421797STejun Heo (cpu) < WORK_CPU_NONE; \ 303f3421797STejun Heo (cpu) = __next_gcwq_cpu((cpu), cpu_online_mask, 3)) 304f3421797STejun Heo 305f3421797STejun Heo #define for_each_cwq_cpu(cpu, wq) \ 306f3421797STejun Heo for ((cpu) = __next_wq_cpu(-1, cpu_possible_mask, (wq)); \ 307f3421797STejun Heo (cpu) < WORK_CPU_NONE; \ 308f3421797STejun Heo (cpu) = __next_wq_cpu((cpu), cpu_possible_mask, (wq))) 309f3421797STejun Heo 310dc186ad7SThomas Gleixner #ifdef CONFIG_DEBUG_OBJECTS_WORK 311dc186ad7SThomas Gleixner 312dc186ad7SThomas Gleixner static struct debug_obj_descr work_debug_descr; 313dc186ad7SThomas Gleixner 31499777288SStanislaw Gruszka static void *work_debug_hint(void *addr) 31599777288SStanislaw Gruszka { 31699777288SStanislaw Gruszka return ((struct work_struct *) addr)->func; 31799777288SStanislaw Gruszka } 31899777288SStanislaw Gruszka 319dc186ad7SThomas Gleixner /* 320dc186ad7SThomas Gleixner * fixup_init is called when: 321dc186ad7SThomas Gleixner * - an active object is initialized 322dc186ad7SThomas Gleixner */ 323dc186ad7SThomas Gleixner static int work_fixup_init(void *addr, enum debug_obj_state state) 324dc186ad7SThomas Gleixner { 325dc186ad7SThomas Gleixner struct work_struct *work = addr; 326dc186ad7SThomas Gleixner 327dc186ad7SThomas Gleixner switch (state) { 328dc186ad7SThomas Gleixner case ODEBUG_STATE_ACTIVE: 329dc186ad7SThomas Gleixner cancel_work_sync(work); 330dc186ad7SThomas Gleixner debug_object_init(work, &work_debug_descr); 331dc186ad7SThomas Gleixner return 1; 332dc186ad7SThomas Gleixner default: 333dc186ad7SThomas Gleixner return 0; 334dc186ad7SThomas Gleixner } 335dc186ad7SThomas Gleixner } 336dc186ad7SThomas Gleixner 337dc186ad7SThomas Gleixner /* 338dc186ad7SThomas Gleixner * fixup_activate is called when: 339dc186ad7SThomas Gleixner * - an active object is activated 340dc186ad7SThomas Gleixner * - an unknown object is activated (might be a statically initialized object) 341dc186ad7SThomas Gleixner */ 342dc186ad7SThomas Gleixner static int work_fixup_activate(void *addr, enum debug_obj_state state) 343dc186ad7SThomas Gleixner { 344dc186ad7SThomas Gleixner struct work_struct *work = addr; 345dc186ad7SThomas Gleixner 346dc186ad7SThomas Gleixner switch (state) { 347dc186ad7SThomas Gleixner 348dc186ad7SThomas Gleixner case ODEBUG_STATE_NOTAVAILABLE: 349dc186ad7SThomas Gleixner /* 350dc186ad7SThomas Gleixner * This is not really a fixup. The work struct was 351dc186ad7SThomas Gleixner * statically initialized. We just make sure that it 352dc186ad7SThomas Gleixner * is tracked in the object tracker. 353dc186ad7SThomas Gleixner */ 35422df02bbSTejun Heo if (test_bit(WORK_STRUCT_STATIC_BIT, work_data_bits(work))) { 355dc186ad7SThomas Gleixner debug_object_init(work, &work_debug_descr); 356dc186ad7SThomas Gleixner debug_object_activate(work, &work_debug_descr); 357dc186ad7SThomas Gleixner return 0; 358dc186ad7SThomas Gleixner } 359dc186ad7SThomas Gleixner WARN_ON_ONCE(1); 360dc186ad7SThomas Gleixner return 0; 361dc186ad7SThomas Gleixner 362dc186ad7SThomas Gleixner case ODEBUG_STATE_ACTIVE: 363dc186ad7SThomas Gleixner WARN_ON(1); 364dc186ad7SThomas Gleixner 365dc186ad7SThomas Gleixner default: 366dc186ad7SThomas Gleixner return 0; 367dc186ad7SThomas Gleixner } 368dc186ad7SThomas Gleixner } 369dc186ad7SThomas Gleixner 370dc186ad7SThomas Gleixner /* 371dc186ad7SThomas Gleixner * fixup_free is called when: 372dc186ad7SThomas Gleixner * - an active object is freed 373dc186ad7SThomas Gleixner */ 374dc186ad7SThomas Gleixner static int work_fixup_free(void *addr, enum debug_obj_state state) 375dc186ad7SThomas Gleixner { 376dc186ad7SThomas Gleixner struct work_struct *work = addr; 377dc186ad7SThomas Gleixner 378dc186ad7SThomas Gleixner switch (state) { 379dc186ad7SThomas Gleixner case ODEBUG_STATE_ACTIVE: 380dc186ad7SThomas Gleixner cancel_work_sync(work); 381dc186ad7SThomas Gleixner debug_object_free(work, &work_debug_descr); 382dc186ad7SThomas Gleixner return 1; 383dc186ad7SThomas Gleixner default: 384dc186ad7SThomas Gleixner return 0; 385dc186ad7SThomas Gleixner } 386dc186ad7SThomas Gleixner } 387dc186ad7SThomas Gleixner 388dc186ad7SThomas Gleixner static struct debug_obj_descr work_debug_descr = { 389dc186ad7SThomas Gleixner .name = "work_struct", 39099777288SStanislaw Gruszka .debug_hint = work_debug_hint, 391dc186ad7SThomas Gleixner .fixup_init = work_fixup_init, 392dc186ad7SThomas Gleixner .fixup_activate = work_fixup_activate, 393dc186ad7SThomas Gleixner .fixup_free = work_fixup_free, 394dc186ad7SThomas Gleixner }; 395dc186ad7SThomas Gleixner 396dc186ad7SThomas Gleixner static inline void debug_work_activate(struct work_struct *work) 397dc186ad7SThomas Gleixner { 398dc186ad7SThomas Gleixner debug_object_activate(work, &work_debug_descr); 399dc186ad7SThomas Gleixner } 400dc186ad7SThomas Gleixner 401dc186ad7SThomas Gleixner static inline void debug_work_deactivate(struct work_struct *work) 402dc186ad7SThomas Gleixner { 403dc186ad7SThomas Gleixner debug_object_deactivate(work, &work_debug_descr); 404dc186ad7SThomas Gleixner } 405dc186ad7SThomas Gleixner 406dc186ad7SThomas Gleixner void __init_work(struct work_struct *work, int onstack) 407dc186ad7SThomas Gleixner { 408dc186ad7SThomas Gleixner if (onstack) 409dc186ad7SThomas Gleixner debug_object_init_on_stack(work, &work_debug_descr); 410dc186ad7SThomas Gleixner else 411dc186ad7SThomas Gleixner debug_object_init(work, &work_debug_descr); 412dc186ad7SThomas Gleixner } 413dc186ad7SThomas Gleixner EXPORT_SYMBOL_GPL(__init_work); 414dc186ad7SThomas Gleixner 415dc186ad7SThomas Gleixner void destroy_work_on_stack(struct work_struct *work) 416dc186ad7SThomas Gleixner { 417dc186ad7SThomas Gleixner debug_object_free(work, &work_debug_descr); 418dc186ad7SThomas Gleixner } 419dc186ad7SThomas Gleixner EXPORT_SYMBOL_GPL(destroy_work_on_stack); 420dc186ad7SThomas Gleixner 421dc186ad7SThomas Gleixner #else 422dc186ad7SThomas Gleixner static inline void debug_work_activate(struct work_struct *work) { } 423dc186ad7SThomas Gleixner static inline void debug_work_deactivate(struct work_struct *work) { } 424dc186ad7SThomas Gleixner #endif 425dc186ad7SThomas Gleixner 42695402b38SGautham R Shenoy /* Serializes the accesses to the list of workqueues. */ 42795402b38SGautham R Shenoy static DEFINE_SPINLOCK(workqueue_lock); 4281da177e4SLinus Torvalds static LIST_HEAD(workqueues); 429a0a1a5fdSTejun Heo static bool workqueue_freezing; /* W: have wqs started freezing? */ 4301da177e4SLinus Torvalds 43114441960SOleg Nesterov /* 432e22bee78STejun Heo * The almighty global cpu workqueues. nr_running is the only field 433e22bee78STejun Heo * which is expected to be used frequently by other cpus via 434e22bee78STejun Heo * try_to_wake_up(). Put it in a separate cacheline. 43514441960SOleg Nesterov */ 4368b03ae3cSTejun Heo static DEFINE_PER_CPU(struct global_cwq, global_cwq); 437e34cdddbSTejun Heo static DEFINE_PER_CPU_SHARED_ALIGNED(atomic_t, pool_nr_running[NR_STD_WORKER_POOLS]); 438f756d5e2SNathan Lynch 439f3421797STejun Heo /* 44024647570STejun Heo * Global cpu workqueue and nr_running counter for unbound gcwq. The pools 44124647570STejun Heo * for online CPUs have POOL_DISASSOCIATED set, and all their workers have 44224647570STejun Heo * WORKER_UNBOUND set. 443f3421797STejun Heo */ 444f3421797STejun Heo static struct global_cwq unbound_global_cwq; 445e34cdddbSTejun Heo static atomic_t unbound_pool_nr_running[NR_STD_WORKER_POOLS] = { 446e34cdddbSTejun Heo [0 ... NR_STD_WORKER_POOLS - 1] = ATOMIC_INIT(0), /* always 0 */ 4474ce62e9eSTejun Heo }; 448f3421797STejun Heo 4499daf9e67STejun Heo /* idr of all pools */ 4509daf9e67STejun Heo static DEFINE_MUTEX(worker_pool_idr_mutex); 4519daf9e67STejun Heo static DEFINE_IDR(worker_pool_idr); 4529daf9e67STejun Heo 453c34056a3STejun Heo static int worker_thread(void *__worker); 4541da177e4SLinus Torvalds 455e34cdddbSTejun Heo static int std_worker_pool_pri(struct worker_pool *pool) 4563270476aSTejun Heo { 4573270476aSTejun Heo return pool - pool->gcwq->pools; 4583270476aSTejun Heo } 4593270476aSTejun Heo 4608b03ae3cSTejun Heo static struct global_cwq *get_gcwq(unsigned int cpu) 4611da177e4SLinus Torvalds { 462f3421797STejun Heo if (cpu != WORK_CPU_UNBOUND) 4638b03ae3cSTejun Heo return &per_cpu(global_cwq, cpu); 464f3421797STejun Heo else 465f3421797STejun Heo return &unbound_global_cwq; 4661da177e4SLinus Torvalds } 4671da177e4SLinus Torvalds 4689daf9e67STejun Heo /* allocate ID and assign it to @pool */ 4699daf9e67STejun Heo static int worker_pool_assign_id(struct worker_pool *pool) 4709daf9e67STejun Heo { 4719daf9e67STejun Heo int ret; 4729daf9e67STejun Heo 4739daf9e67STejun Heo mutex_lock(&worker_pool_idr_mutex); 4749daf9e67STejun Heo idr_pre_get(&worker_pool_idr, GFP_KERNEL); 4759daf9e67STejun Heo ret = idr_get_new(&worker_pool_idr, pool, &pool->id); 4769daf9e67STejun Heo mutex_unlock(&worker_pool_idr_mutex); 4779daf9e67STejun Heo 4789daf9e67STejun Heo return ret; 4799daf9e67STejun Heo } 4809daf9e67STejun Heo 4817c3eed5cSTejun Heo /* 4827c3eed5cSTejun Heo * Lookup worker_pool by id. The idr currently is built during boot and 4837c3eed5cSTejun Heo * never modified. Don't worry about locking for now. 4847c3eed5cSTejun Heo */ 4857c3eed5cSTejun Heo static struct worker_pool *worker_pool_by_id(int pool_id) 4867c3eed5cSTejun Heo { 4877c3eed5cSTejun Heo return idr_find(&worker_pool_idr, pool_id); 4887c3eed5cSTejun Heo } 4897c3eed5cSTejun Heo 49063d95a91STejun Heo static atomic_t *get_pool_nr_running(struct worker_pool *pool) 491b1f4ec17SOleg Nesterov { 492ec22ca5eSTejun Heo int cpu = pool->cpu; 493e34cdddbSTejun Heo int idx = std_worker_pool_pri(pool); 49463d95a91STejun Heo 495f3421797STejun Heo if (cpu != WORK_CPU_UNBOUND) 4964ce62e9eSTejun Heo return &per_cpu(pool_nr_running, cpu)[idx]; 497f3421797STejun Heo else 4984ce62e9eSTejun Heo return &unbound_pool_nr_running[idx]; 499b1f4ec17SOleg Nesterov } 500b1f4ec17SOleg Nesterov 5014690c4abSTejun Heo static struct cpu_workqueue_struct *get_cwq(unsigned int cpu, 5024690c4abSTejun Heo struct workqueue_struct *wq) 503a848e3b6SOleg Nesterov { 504f3421797STejun Heo if (!(wq->flags & WQ_UNBOUND)) { 505e06ffa1eSLai Jiangshan if (likely(cpu < nr_cpu_ids)) 506bdbc5dd7STejun Heo return per_cpu_ptr(wq->cpu_wq.pcpu, cpu); 507f3421797STejun Heo } else if (likely(cpu == WORK_CPU_UNBOUND)) 508f3421797STejun Heo return wq->cpu_wq.single; 509f3421797STejun Heo return NULL; 510f3421797STejun Heo } 511a848e3b6SOleg Nesterov 51273f53c4aSTejun Heo static unsigned int work_color_to_flags(int color) 51373f53c4aSTejun Heo { 51473f53c4aSTejun Heo return color << WORK_STRUCT_COLOR_SHIFT; 51573f53c4aSTejun Heo } 51673f53c4aSTejun Heo 51773f53c4aSTejun Heo static int get_work_color(struct work_struct *work) 51873f53c4aSTejun Heo { 51973f53c4aSTejun Heo return (*work_data_bits(work) >> WORK_STRUCT_COLOR_SHIFT) & 52073f53c4aSTejun Heo ((1 << WORK_STRUCT_COLOR_BITS) - 1); 52173f53c4aSTejun Heo } 52273f53c4aSTejun Heo 52373f53c4aSTejun Heo static int work_next_color(int color) 52473f53c4aSTejun Heo { 52573f53c4aSTejun Heo return (color + 1) % WORK_NR_COLORS; 5261da177e4SLinus Torvalds } 5271da177e4SLinus Torvalds 5284594bf15SDavid Howells /* 529b5490077STejun Heo * While queued, %WORK_STRUCT_CWQ is set and non flag bits of a work's data 530b5490077STejun Heo * contain the pointer to the queued cwq. Once execution starts, the flag 5317c3eed5cSTejun Heo * is cleared and the high bits contain OFFQ flags and pool ID. 5327a22ad75STejun Heo * 5337c3eed5cSTejun Heo * set_work_cwq(), set_work_pool_and_clear_pending(), mark_work_canceling() 5347c3eed5cSTejun Heo * and clear_work_data() can be used to set the cwq, pool or clear 535bbb68dfaSTejun Heo * work->data. These functions should only be called while the work is 536bbb68dfaSTejun Heo * owned - ie. while the PENDING bit is set. 5377a22ad75STejun Heo * 5387c3eed5cSTejun Heo * get_work_pool() and get_work_cwq() can be used to obtain the pool or cwq 5397c3eed5cSTejun Heo * corresponding to a work. Pool is available once the work has been 5407c3eed5cSTejun Heo * queued anywhere after initialization until it is sync canceled. cwq is 5417c3eed5cSTejun Heo * available only while the work item is queued. 542bbb68dfaSTejun Heo * 543bbb68dfaSTejun Heo * %WORK_OFFQ_CANCELING is used to mark a work item which is being 544bbb68dfaSTejun Heo * canceled. While being canceled, a work item may have its PENDING set 545bbb68dfaSTejun Heo * but stay off timer and worklist for arbitrarily long and nobody should 546bbb68dfaSTejun Heo * try to steal the PENDING bit. 5474594bf15SDavid Howells */ 5487a22ad75STejun Heo static inline void set_work_data(struct work_struct *work, unsigned long data, 5497a22ad75STejun Heo unsigned long flags) 5507a22ad75STejun Heo { 5517a22ad75STejun Heo BUG_ON(!work_pending(work)); 5527a22ad75STejun Heo atomic_long_set(&work->data, data | flags | work_static(work)); 5537a22ad75STejun Heo } 5547a22ad75STejun Heo 5557a22ad75STejun Heo static void set_work_cwq(struct work_struct *work, 5564690c4abSTejun Heo struct cpu_workqueue_struct *cwq, 5574690c4abSTejun Heo unsigned long extra_flags) 558365970a1SDavid Howells { 5597a22ad75STejun Heo set_work_data(work, (unsigned long)cwq, 560e120153dSTejun Heo WORK_STRUCT_PENDING | WORK_STRUCT_CWQ | extra_flags); 561365970a1SDavid Howells } 562365970a1SDavid Howells 5637c3eed5cSTejun Heo static void set_work_pool_and_clear_pending(struct work_struct *work, 5647c3eed5cSTejun Heo int pool_id) 5654d707b9fSOleg Nesterov { 56623657bb1STejun Heo /* 56723657bb1STejun Heo * The following wmb is paired with the implied mb in 56823657bb1STejun Heo * test_and_set_bit(PENDING) and ensures all updates to @work made 56923657bb1STejun Heo * here are visible to and precede any updates by the next PENDING 57023657bb1STejun Heo * owner. 57123657bb1STejun Heo */ 57223657bb1STejun Heo smp_wmb(); 5737c3eed5cSTejun Heo set_work_data(work, (unsigned long)pool_id << WORK_OFFQ_POOL_SHIFT, 0); 5744d707b9fSOleg Nesterov } 5754d707b9fSOleg Nesterov 5767a22ad75STejun Heo static void clear_work_data(struct work_struct *work) 577365970a1SDavid Howells { 5787c3eed5cSTejun Heo smp_wmb(); /* see set_work_pool_and_clear_pending() */ 5797c3eed5cSTejun Heo set_work_data(work, WORK_STRUCT_NO_POOL, 0); 5807a22ad75STejun Heo } 5817a22ad75STejun Heo 5827a22ad75STejun Heo static struct cpu_workqueue_struct *get_work_cwq(struct work_struct *work) 5837a22ad75STejun Heo { 584e120153dSTejun Heo unsigned long data = atomic_long_read(&work->data); 5857a22ad75STejun Heo 586e120153dSTejun Heo if (data & WORK_STRUCT_CWQ) 587e120153dSTejun Heo return (void *)(data & WORK_STRUCT_WQ_DATA_MASK); 588e120153dSTejun Heo else 589e120153dSTejun Heo return NULL; 5907a22ad75STejun Heo } 5917a22ad75STejun Heo 5927c3eed5cSTejun Heo /** 5937c3eed5cSTejun Heo * get_work_pool - return the worker_pool a given work was associated with 5947c3eed5cSTejun Heo * @work: the work item of interest 5957c3eed5cSTejun Heo * 5967c3eed5cSTejun Heo * Return the worker_pool @work was last associated with. %NULL if none. 5977c3eed5cSTejun Heo */ 5987c3eed5cSTejun Heo static struct worker_pool *get_work_pool(struct work_struct *work) 5997a22ad75STejun Heo { 600e120153dSTejun Heo unsigned long data = atomic_long_read(&work->data); 6017c3eed5cSTejun Heo struct worker_pool *pool; 6027c3eed5cSTejun Heo int pool_id; 6037a22ad75STejun Heo 604e120153dSTejun Heo if (data & WORK_STRUCT_CWQ) 605e120153dSTejun Heo return ((struct cpu_workqueue_struct *) 6067c3eed5cSTejun Heo (data & WORK_STRUCT_WQ_DATA_MASK))->pool; 6077a22ad75STejun Heo 6087c3eed5cSTejun Heo pool_id = data >> WORK_OFFQ_POOL_SHIFT; 6097c3eed5cSTejun Heo if (pool_id == WORK_OFFQ_POOL_NONE) 6107a22ad75STejun Heo return NULL; 6117a22ad75STejun Heo 6127c3eed5cSTejun Heo pool = worker_pool_by_id(pool_id); 6137c3eed5cSTejun Heo WARN_ON_ONCE(!pool); 6147c3eed5cSTejun Heo return pool; 6157c3eed5cSTejun Heo } 6167c3eed5cSTejun Heo 6177c3eed5cSTejun Heo /** 6187c3eed5cSTejun Heo * get_work_pool_id - return the worker pool ID a given work is associated with 6197c3eed5cSTejun Heo * @work: the work item of interest 6207c3eed5cSTejun Heo * 6217c3eed5cSTejun Heo * Return the worker_pool ID @work was last associated with. 6227c3eed5cSTejun Heo * %WORK_OFFQ_POOL_NONE if none. 6237c3eed5cSTejun Heo */ 6247c3eed5cSTejun Heo static int get_work_pool_id(struct work_struct *work) 6257c3eed5cSTejun Heo { 6267c3eed5cSTejun Heo struct worker_pool *pool = get_work_pool(work); 6277c3eed5cSTejun Heo 6287c3eed5cSTejun Heo return pool ? pool->id : WORK_OFFQ_POOL_NONE; 6297c3eed5cSTejun Heo } 6307c3eed5cSTejun Heo 6317c3eed5cSTejun Heo static struct global_cwq *get_work_gcwq(struct work_struct *work) 6327c3eed5cSTejun Heo { 6337c3eed5cSTejun Heo struct worker_pool *pool = get_work_pool(work); 6347c3eed5cSTejun Heo 6357c3eed5cSTejun Heo return pool ? pool->gcwq : NULL; 636365970a1SDavid Howells } 637365970a1SDavid Howells 638bbb68dfaSTejun Heo static void mark_work_canceling(struct work_struct *work) 639bbb68dfaSTejun Heo { 6407c3eed5cSTejun Heo unsigned long pool_id = get_work_pool_id(work); 641bbb68dfaSTejun Heo 6427c3eed5cSTejun Heo pool_id <<= WORK_OFFQ_POOL_SHIFT; 6437c3eed5cSTejun Heo set_work_data(work, pool_id | WORK_OFFQ_CANCELING, WORK_STRUCT_PENDING); 644bbb68dfaSTejun Heo } 645bbb68dfaSTejun Heo 646bbb68dfaSTejun Heo static bool work_is_canceling(struct work_struct *work) 647bbb68dfaSTejun Heo { 648bbb68dfaSTejun Heo unsigned long data = atomic_long_read(&work->data); 649bbb68dfaSTejun Heo 650bbb68dfaSTejun Heo return !(data & WORK_STRUCT_CWQ) && (data & WORK_OFFQ_CANCELING); 651bbb68dfaSTejun Heo } 652bbb68dfaSTejun Heo 653e22bee78STejun Heo /* 6543270476aSTejun Heo * Policy functions. These define the policies on how the global worker 6553270476aSTejun Heo * pools are managed. Unless noted otherwise, these functions assume that 6563270476aSTejun Heo * they're being called with gcwq->lock held. 657e22bee78STejun Heo */ 658e22bee78STejun Heo 65963d95a91STejun Heo static bool __need_more_worker(struct worker_pool *pool) 660649027d7STejun Heo { 6613270476aSTejun Heo return !atomic_read(get_pool_nr_running(pool)); 662649027d7STejun Heo } 663649027d7STejun Heo 664e22bee78STejun Heo /* 665e22bee78STejun Heo * Need to wake up a worker? Called from anything but currently 666e22bee78STejun Heo * running workers. 667974271c4STejun Heo * 668974271c4STejun Heo * Note that, because unbound workers never contribute to nr_running, this 669974271c4STejun Heo * function will always return %true for unbound gcwq as long as the 670974271c4STejun Heo * worklist isn't empty. 671e22bee78STejun Heo */ 67263d95a91STejun Heo static bool need_more_worker(struct worker_pool *pool) 673e22bee78STejun Heo { 67463d95a91STejun Heo return !list_empty(&pool->worklist) && __need_more_worker(pool); 675e22bee78STejun Heo } 676e22bee78STejun Heo 677e22bee78STejun Heo /* Can I start working? Called from busy but !running workers. */ 67863d95a91STejun Heo static bool may_start_working(struct worker_pool *pool) 679e22bee78STejun Heo { 68063d95a91STejun Heo return pool->nr_idle; 681e22bee78STejun Heo } 682e22bee78STejun Heo 683e22bee78STejun Heo /* Do I need to keep working? Called from currently running workers. */ 68463d95a91STejun Heo static bool keep_working(struct worker_pool *pool) 685e22bee78STejun Heo { 68663d95a91STejun Heo atomic_t *nr_running = get_pool_nr_running(pool); 687e22bee78STejun Heo 6883270476aSTejun Heo return !list_empty(&pool->worklist) && atomic_read(nr_running) <= 1; 689e22bee78STejun Heo } 690e22bee78STejun Heo 691e22bee78STejun Heo /* Do we need a new worker? Called from manager. */ 69263d95a91STejun Heo static bool need_to_create_worker(struct worker_pool *pool) 693e22bee78STejun Heo { 69463d95a91STejun Heo return need_more_worker(pool) && !may_start_working(pool); 695e22bee78STejun Heo } 696e22bee78STejun Heo 697e22bee78STejun Heo /* Do I need to be the manager? */ 69863d95a91STejun Heo static bool need_to_manage_workers(struct worker_pool *pool) 699e22bee78STejun Heo { 70063d95a91STejun Heo return need_to_create_worker(pool) || 70111ebea50STejun Heo (pool->flags & POOL_MANAGE_WORKERS); 702e22bee78STejun Heo } 703e22bee78STejun Heo 704e22bee78STejun Heo /* Do we have too many workers and should some go away? */ 70563d95a91STejun Heo static bool too_many_workers(struct worker_pool *pool) 706e22bee78STejun Heo { 707552a37e9SLai Jiangshan bool managing = pool->flags & POOL_MANAGING_WORKERS; 70863d95a91STejun Heo int nr_idle = pool->nr_idle + managing; /* manager is considered idle */ 70963d95a91STejun Heo int nr_busy = pool->nr_workers - nr_idle; 710e22bee78STejun Heo 711ea1abd61SLai Jiangshan /* 712ea1abd61SLai Jiangshan * nr_idle and idle_list may disagree if idle rebinding is in 713ea1abd61SLai Jiangshan * progress. Never return %true if idle_list is empty. 714ea1abd61SLai Jiangshan */ 715ea1abd61SLai Jiangshan if (list_empty(&pool->idle_list)) 716ea1abd61SLai Jiangshan return false; 717ea1abd61SLai Jiangshan 718e22bee78STejun Heo return nr_idle > 2 && (nr_idle - 2) * MAX_IDLE_WORKERS_RATIO >= nr_busy; 719e22bee78STejun Heo } 720e22bee78STejun Heo 721e22bee78STejun Heo /* 722e22bee78STejun Heo * Wake up functions. 723e22bee78STejun Heo */ 724e22bee78STejun Heo 7257e11629dSTejun Heo /* Return the first worker. Safe with preemption disabled */ 72663d95a91STejun Heo static struct worker *first_worker(struct worker_pool *pool) 7277e11629dSTejun Heo { 72863d95a91STejun Heo if (unlikely(list_empty(&pool->idle_list))) 7297e11629dSTejun Heo return NULL; 7307e11629dSTejun Heo 73163d95a91STejun Heo return list_first_entry(&pool->idle_list, struct worker, entry); 7327e11629dSTejun Heo } 7337e11629dSTejun Heo 7347e11629dSTejun Heo /** 7357e11629dSTejun Heo * wake_up_worker - wake up an idle worker 73663d95a91STejun Heo * @pool: worker pool to wake worker from 7377e11629dSTejun Heo * 73863d95a91STejun Heo * Wake up the first idle worker of @pool. 7397e11629dSTejun Heo * 7407e11629dSTejun Heo * CONTEXT: 7417e11629dSTejun Heo * spin_lock_irq(gcwq->lock). 7427e11629dSTejun Heo */ 74363d95a91STejun Heo static void wake_up_worker(struct worker_pool *pool) 7447e11629dSTejun Heo { 74563d95a91STejun Heo struct worker *worker = first_worker(pool); 7467e11629dSTejun Heo 7477e11629dSTejun Heo if (likely(worker)) 7487e11629dSTejun Heo wake_up_process(worker->task); 7497e11629dSTejun Heo } 7507e11629dSTejun Heo 7514690c4abSTejun Heo /** 752e22bee78STejun Heo * wq_worker_waking_up - a worker is waking up 753e22bee78STejun Heo * @task: task waking up 754e22bee78STejun Heo * @cpu: CPU @task is waking up to 755e22bee78STejun Heo * 756e22bee78STejun Heo * This function is called during try_to_wake_up() when a worker is 757e22bee78STejun Heo * being awoken. 758e22bee78STejun Heo * 759e22bee78STejun Heo * CONTEXT: 760e22bee78STejun Heo * spin_lock_irq(rq->lock) 761e22bee78STejun Heo */ 762e22bee78STejun Heo void wq_worker_waking_up(struct task_struct *task, unsigned int cpu) 763e22bee78STejun Heo { 764e22bee78STejun Heo struct worker *worker = kthread_data(task); 765e22bee78STejun Heo 76636576000SJoonsoo Kim if (!(worker->flags & WORKER_NOT_RUNNING)) { 767ec22ca5eSTejun Heo WARN_ON_ONCE(worker->pool->cpu != cpu); 76863d95a91STejun Heo atomic_inc(get_pool_nr_running(worker->pool)); 769e22bee78STejun Heo } 77036576000SJoonsoo Kim } 771e22bee78STejun Heo 772e22bee78STejun Heo /** 773e22bee78STejun Heo * wq_worker_sleeping - a worker is going to sleep 774e22bee78STejun Heo * @task: task going to sleep 775e22bee78STejun Heo * @cpu: CPU in question, must be the current CPU number 776e22bee78STejun Heo * 777e22bee78STejun Heo * This function is called during schedule() when a busy worker is 778e22bee78STejun Heo * going to sleep. Worker on the same cpu can be woken up by 779e22bee78STejun Heo * returning pointer to its task. 780e22bee78STejun Heo * 781e22bee78STejun Heo * CONTEXT: 782e22bee78STejun Heo * spin_lock_irq(rq->lock) 783e22bee78STejun Heo * 784e22bee78STejun Heo * RETURNS: 785e22bee78STejun Heo * Worker task on @cpu to wake up, %NULL if none. 786e22bee78STejun Heo */ 787e22bee78STejun Heo struct task_struct *wq_worker_sleeping(struct task_struct *task, 788e22bee78STejun Heo unsigned int cpu) 789e22bee78STejun Heo { 790e22bee78STejun Heo struct worker *worker = kthread_data(task), *to_wakeup = NULL; 791111c225aSTejun Heo struct worker_pool *pool; 792111c225aSTejun Heo atomic_t *nr_running; 793e22bee78STejun Heo 794111c225aSTejun Heo /* 795111c225aSTejun Heo * Rescuers, which may not have all the fields set up like normal 796111c225aSTejun Heo * workers, also reach here, let's not access anything before 797111c225aSTejun Heo * checking NOT_RUNNING. 798111c225aSTejun Heo */ 7992d64672eSSteven Rostedt if (worker->flags & WORKER_NOT_RUNNING) 800e22bee78STejun Heo return NULL; 801e22bee78STejun Heo 802111c225aSTejun Heo pool = worker->pool; 803111c225aSTejun Heo nr_running = get_pool_nr_running(pool); 804111c225aSTejun Heo 805e22bee78STejun Heo /* this can only happen on the local cpu */ 806e22bee78STejun Heo BUG_ON(cpu != raw_smp_processor_id()); 807e22bee78STejun Heo 808e22bee78STejun Heo /* 809e22bee78STejun Heo * The counterpart of the following dec_and_test, implied mb, 810e22bee78STejun Heo * worklist not empty test sequence is in insert_work(). 811e22bee78STejun Heo * Please read comment there. 812e22bee78STejun Heo * 813628c78e7STejun Heo * NOT_RUNNING is clear. This means that we're bound to and 814628c78e7STejun Heo * running on the local cpu w/ rq lock held and preemption 815628c78e7STejun Heo * disabled, which in turn means that none else could be 816628c78e7STejun Heo * manipulating idle_list, so dereferencing idle_list without gcwq 817628c78e7STejun Heo * lock is safe. 818e22bee78STejun Heo */ 819bd7bdd43STejun Heo if (atomic_dec_and_test(nr_running) && !list_empty(&pool->worklist)) 82063d95a91STejun Heo to_wakeup = first_worker(pool); 821e22bee78STejun Heo return to_wakeup ? to_wakeup->task : NULL; 822e22bee78STejun Heo } 823e22bee78STejun Heo 824e22bee78STejun Heo /** 825e22bee78STejun Heo * worker_set_flags - set worker flags and adjust nr_running accordingly 826cb444766STejun Heo * @worker: self 827d302f017STejun Heo * @flags: flags to set 828d302f017STejun Heo * @wakeup: wakeup an idle worker if necessary 829d302f017STejun Heo * 830e22bee78STejun Heo * Set @flags in @worker->flags and adjust nr_running accordingly. If 831e22bee78STejun Heo * nr_running becomes zero and @wakeup is %true, an idle worker is 832e22bee78STejun Heo * woken up. 833d302f017STejun Heo * 834cb444766STejun Heo * CONTEXT: 835cb444766STejun Heo * spin_lock_irq(gcwq->lock) 836d302f017STejun Heo */ 837d302f017STejun Heo static inline void worker_set_flags(struct worker *worker, unsigned int flags, 838d302f017STejun Heo bool wakeup) 839d302f017STejun Heo { 840bd7bdd43STejun Heo struct worker_pool *pool = worker->pool; 841e22bee78STejun Heo 842cb444766STejun Heo WARN_ON_ONCE(worker->task != current); 843cb444766STejun Heo 844e22bee78STejun Heo /* 845e22bee78STejun Heo * If transitioning into NOT_RUNNING, adjust nr_running and 846e22bee78STejun Heo * wake up an idle worker as necessary if requested by 847e22bee78STejun Heo * @wakeup. 848e22bee78STejun Heo */ 849e22bee78STejun Heo if ((flags & WORKER_NOT_RUNNING) && 850e22bee78STejun Heo !(worker->flags & WORKER_NOT_RUNNING)) { 85163d95a91STejun Heo atomic_t *nr_running = get_pool_nr_running(pool); 852e22bee78STejun Heo 853e22bee78STejun Heo if (wakeup) { 854e22bee78STejun Heo if (atomic_dec_and_test(nr_running) && 855bd7bdd43STejun Heo !list_empty(&pool->worklist)) 85663d95a91STejun Heo wake_up_worker(pool); 857e22bee78STejun Heo } else 858e22bee78STejun Heo atomic_dec(nr_running); 859e22bee78STejun Heo } 860e22bee78STejun Heo 861d302f017STejun Heo worker->flags |= flags; 862d302f017STejun Heo } 863d302f017STejun Heo 864d302f017STejun Heo /** 865e22bee78STejun Heo * worker_clr_flags - clear worker flags and adjust nr_running accordingly 866cb444766STejun Heo * @worker: self 867d302f017STejun Heo * @flags: flags to clear 868d302f017STejun Heo * 869e22bee78STejun Heo * Clear @flags in @worker->flags and adjust nr_running accordingly. 870d302f017STejun Heo * 871cb444766STejun Heo * CONTEXT: 872cb444766STejun Heo * spin_lock_irq(gcwq->lock) 873d302f017STejun Heo */ 874d302f017STejun Heo static inline void worker_clr_flags(struct worker *worker, unsigned int flags) 875d302f017STejun Heo { 87663d95a91STejun Heo struct worker_pool *pool = worker->pool; 877e22bee78STejun Heo unsigned int oflags = worker->flags; 878e22bee78STejun Heo 879cb444766STejun Heo WARN_ON_ONCE(worker->task != current); 880cb444766STejun Heo 881d302f017STejun Heo worker->flags &= ~flags; 882e22bee78STejun Heo 88342c025f3STejun Heo /* 88442c025f3STejun Heo * If transitioning out of NOT_RUNNING, increment nr_running. Note 88542c025f3STejun Heo * that the nested NOT_RUNNING is not a noop. NOT_RUNNING is mask 88642c025f3STejun Heo * of multiple flags, not a single flag. 88742c025f3STejun Heo */ 888e22bee78STejun Heo if ((flags & WORKER_NOT_RUNNING) && (oflags & WORKER_NOT_RUNNING)) 889e22bee78STejun Heo if (!(worker->flags & WORKER_NOT_RUNNING)) 89063d95a91STejun Heo atomic_inc(get_pool_nr_running(pool)); 891d302f017STejun Heo } 892d302f017STejun Heo 893d302f017STejun Heo /** 8948cca0eeaSTejun Heo * find_worker_executing_work - find worker which is executing a work 895c9e7cf27STejun Heo * @pool: pool of interest 8968cca0eeaSTejun Heo * @work: work to find worker for 8978cca0eeaSTejun Heo * 898c9e7cf27STejun Heo * Find a worker which is executing @work on @pool by searching 899c9e7cf27STejun Heo * @pool->busy_hash which is keyed by the address of @work. For a worker 900a2c1c57bSTejun Heo * to match, its current execution should match the address of @work and 901a2c1c57bSTejun Heo * its work function. This is to avoid unwanted dependency between 902a2c1c57bSTejun Heo * unrelated work executions through a work item being recycled while still 903a2c1c57bSTejun Heo * being executed. 904a2c1c57bSTejun Heo * 905a2c1c57bSTejun Heo * This is a bit tricky. A work item may be freed once its execution 906a2c1c57bSTejun Heo * starts and nothing prevents the freed area from being recycled for 907a2c1c57bSTejun Heo * another work item. If the same work item address ends up being reused 908a2c1c57bSTejun Heo * before the original execution finishes, workqueue will identify the 909a2c1c57bSTejun Heo * recycled work item as currently executing and make it wait until the 910a2c1c57bSTejun Heo * current execution finishes, introducing an unwanted dependency. 911a2c1c57bSTejun Heo * 912a2c1c57bSTejun Heo * This function checks the work item address, work function and workqueue 913a2c1c57bSTejun Heo * to avoid false positives. Note that this isn't complete as one may 914a2c1c57bSTejun Heo * construct a work function which can introduce dependency onto itself 915a2c1c57bSTejun Heo * through a recycled work item. Well, if somebody wants to shoot oneself 916a2c1c57bSTejun Heo * in the foot that badly, there's only so much we can do, and if such 917a2c1c57bSTejun Heo * deadlock actually occurs, it should be easy to locate the culprit work 918a2c1c57bSTejun Heo * function. 9198cca0eeaSTejun Heo * 9208cca0eeaSTejun Heo * CONTEXT: 9218cca0eeaSTejun Heo * spin_lock_irq(gcwq->lock). 9228cca0eeaSTejun Heo * 9238cca0eeaSTejun Heo * RETURNS: 9248cca0eeaSTejun Heo * Pointer to worker which is executing @work if found, NULL 9258cca0eeaSTejun Heo * otherwise. 9268cca0eeaSTejun Heo */ 927c9e7cf27STejun Heo static struct worker *find_worker_executing_work(struct worker_pool *pool, 9288cca0eeaSTejun Heo struct work_struct *work) 9298cca0eeaSTejun Heo { 93042f8570fSSasha Levin struct worker *worker; 93142f8570fSSasha Levin struct hlist_node *tmp; 93242f8570fSSasha Levin 933c9e7cf27STejun Heo hash_for_each_possible(pool->busy_hash, worker, tmp, hentry, 934a2c1c57bSTejun Heo (unsigned long)work) 935a2c1c57bSTejun Heo if (worker->current_work == work && 936a2c1c57bSTejun Heo worker->current_func == work->func) 93742f8570fSSasha Levin return worker; 93842f8570fSSasha Levin 93942f8570fSSasha Levin return NULL; 9408cca0eeaSTejun Heo } 9418cca0eeaSTejun Heo 9428cca0eeaSTejun Heo /** 943bf4ede01STejun Heo * move_linked_works - move linked works to a list 944bf4ede01STejun Heo * @work: start of series of works to be scheduled 945bf4ede01STejun Heo * @head: target list to append @work to 946bf4ede01STejun Heo * @nextp: out paramter for nested worklist walking 947bf4ede01STejun Heo * 948bf4ede01STejun Heo * Schedule linked works starting from @work to @head. Work series to 949bf4ede01STejun Heo * be scheduled starts at @work and includes any consecutive work with 950bf4ede01STejun Heo * WORK_STRUCT_LINKED set in its predecessor. 951bf4ede01STejun Heo * 952bf4ede01STejun Heo * If @nextp is not NULL, it's updated to point to the next work of 953bf4ede01STejun Heo * the last scheduled work. This allows move_linked_works() to be 954bf4ede01STejun Heo * nested inside outer list_for_each_entry_safe(). 955bf4ede01STejun Heo * 956bf4ede01STejun Heo * CONTEXT: 957bf4ede01STejun Heo * spin_lock_irq(gcwq->lock). 958bf4ede01STejun Heo */ 959bf4ede01STejun Heo static void move_linked_works(struct work_struct *work, struct list_head *head, 960bf4ede01STejun Heo struct work_struct **nextp) 961bf4ede01STejun Heo { 962bf4ede01STejun Heo struct work_struct *n; 963bf4ede01STejun Heo 964bf4ede01STejun Heo /* 965bf4ede01STejun Heo * Linked worklist will always end before the end of the list, 966bf4ede01STejun Heo * use NULL for list head. 967bf4ede01STejun Heo */ 968bf4ede01STejun Heo list_for_each_entry_safe_from(work, n, NULL, entry) { 969bf4ede01STejun Heo list_move_tail(&work->entry, head); 970bf4ede01STejun Heo if (!(*work_data_bits(work) & WORK_STRUCT_LINKED)) 971bf4ede01STejun Heo break; 972bf4ede01STejun Heo } 973bf4ede01STejun Heo 974bf4ede01STejun Heo /* 975bf4ede01STejun Heo * If we're already inside safe list traversal and have moved 976bf4ede01STejun Heo * multiple works to the scheduled queue, the next position 977bf4ede01STejun Heo * needs to be updated. 978bf4ede01STejun Heo */ 979bf4ede01STejun Heo if (nextp) 980bf4ede01STejun Heo *nextp = n; 981bf4ede01STejun Heo } 982bf4ede01STejun Heo 9833aa62497SLai Jiangshan static void cwq_activate_delayed_work(struct work_struct *work) 984bf4ede01STejun Heo { 9853aa62497SLai Jiangshan struct cpu_workqueue_struct *cwq = get_work_cwq(work); 986bf4ede01STejun Heo 987bf4ede01STejun Heo trace_workqueue_activate_work(work); 988bf4ede01STejun Heo move_linked_works(work, &cwq->pool->worklist, NULL); 989bf4ede01STejun Heo __clear_bit(WORK_STRUCT_DELAYED_BIT, work_data_bits(work)); 990bf4ede01STejun Heo cwq->nr_active++; 991bf4ede01STejun Heo } 992bf4ede01STejun Heo 9933aa62497SLai Jiangshan static void cwq_activate_first_delayed(struct cpu_workqueue_struct *cwq) 9943aa62497SLai Jiangshan { 9953aa62497SLai Jiangshan struct work_struct *work = list_first_entry(&cwq->delayed_works, 9963aa62497SLai Jiangshan struct work_struct, entry); 9973aa62497SLai Jiangshan 9983aa62497SLai Jiangshan cwq_activate_delayed_work(work); 9993aa62497SLai Jiangshan } 10003aa62497SLai Jiangshan 1001bf4ede01STejun Heo /** 1002bf4ede01STejun Heo * cwq_dec_nr_in_flight - decrement cwq's nr_in_flight 1003bf4ede01STejun Heo * @cwq: cwq of interest 1004bf4ede01STejun Heo * @color: color of work which left the queue 1005bf4ede01STejun Heo * 1006bf4ede01STejun Heo * A work either has completed or is removed from pending queue, 1007bf4ede01STejun Heo * decrement nr_in_flight of its cwq and handle workqueue flushing. 1008bf4ede01STejun Heo * 1009bf4ede01STejun Heo * CONTEXT: 1010bf4ede01STejun Heo * spin_lock_irq(gcwq->lock). 1011bf4ede01STejun Heo */ 1012b3f9f405SLai Jiangshan static void cwq_dec_nr_in_flight(struct cpu_workqueue_struct *cwq, int color) 1013bf4ede01STejun Heo { 1014bf4ede01STejun Heo /* ignore uncolored works */ 1015bf4ede01STejun Heo if (color == WORK_NO_COLOR) 1016bf4ede01STejun Heo return; 1017bf4ede01STejun Heo 1018bf4ede01STejun Heo cwq->nr_in_flight[color]--; 1019bf4ede01STejun Heo 1020bf4ede01STejun Heo cwq->nr_active--; 1021bf4ede01STejun Heo if (!list_empty(&cwq->delayed_works)) { 1022bf4ede01STejun Heo /* one down, submit a delayed one */ 1023bf4ede01STejun Heo if (cwq->nr_active < cwq->max_active) 1024bf4ede01STejun Heo cwq_activate_first_delayed(cwq); 1025bf4ede01STejun Heo } 1026bf4ede01STejun Heo 1027bf4ede01STejun Heo /* is flush in progress and are we at the flushing tip? */ 1028bf4ede01STejun Heo if (likely(cwq->flush_color != color)) 1029bf4ede01STejun Heo return; 1030bf4ede01STejun Heo 1031bf4ede01STejun Heo /* are there still in-flight works? */ 1032bf4ede01STejun Heo if (cwq->nr_in_flight[color]) 1033bf4ede01STejun Heo return; 1034bf4ede01STejun Heo 1035bf4ede01STejun Heo /* this cwq is done, clear flush_color */ 1036bf4ede01STejun Heo cwq->flush_color = -1; 1037bf4ede01STejun Heo 1038bf4ede01STejun Heo /* 1039bf4ede01STejun Heo * If this was the last cwq, wake up the first flusher. It 1040bf4ede01STejun Heo * will handle the rest. 1041bf4ede01STejun Heo */ 1042bf4ede01STejun Heo if (atomic_dec_and_test(&cwq->wq->nr_cwqs_to_flush)) 1043bf4ede01STejun Heo complete(&cwq->wq->first_flusher->done); 1044bf4ede01STejun Heo } 1045bf4ede01STejun Heo 104636e227d2STejun Heo /** 1047bbb68dfaSTejun Heo * try_to_grab_pending - steal work item from worklist and disable irq 104836e227d2STejun Heo * @work: work item to steal 104936e227d2STejun Heo * @is_dwork: @work is a delayed_work 1050bbb68dfaSTejun Heo * @flags: place to store irq state 105136e227d2STejun Heo * 105236e227d2STejun Heo * Try to grab PENDING bit of @work. This function can handle @work in any 105336e227d2STejun Heo * stable state - idle, on timer or on worklist. Return values are 105436e227d2STejun Heo * 105536e227d2STejun Heo * 1 if @work was pending and we successfully stole PENDING 105636e227d2STejun Heo * 0 if @work was idle and we claimed PENDING 105736e227d2STejun Heo * -EAGAIN if PENDING couldn't be grabbed at the moment, safe to busy-retry 1058bbb68dfaSTejun Heo * -ENOENT if someone else is canceling @work, this state may persist 1059bbb68dfaSTejun Heo * for arbitrarily long 106036e227d2STejun Heo * 1061bbb68dfaSTejun Heo * On >= 0 return, the caller owns @work's PENDING bit. To avoid getting 1062e0aecdd8STejun Heo * interrupted while holding PENDING and @work off queue, irq must be 1063e0aecdd8STejun Heo * disabled on entry. This, combined with delayed_work->timer being 1064e0aecdd8STejun Heo * irqsafe, ensures that we return -EAGAIN for finite short period of time. 1065bbb68dfaSTejun Heo * 1066bbb68dfaSTejun Heo * On successful return, >= 0, irq is disabled and the caller is 1067bbb68dfaSTejun Heo * responsible for releasing it using local_irq_restore(*@flags). 1068bbb68dfaSTejun Heo * 1069e0aecdd8STejun Heo * This function is safe to call from any context including IRQ handler. 1070bf4ede01STejun Heo */ 1071bbb68dfaSTejun Heo static int try_to_grab_pending(struct work_struct *work, bool is_dwork, 1072bbb68dfaSTejun Heo unsigned long *flags) 1073bf4ede01STejun Heo { 1074bf4ede01STejun Heo struct global_cwq *gcwq; 1075bf4ede01STejun Heo 1076bbb68dfaSTejun Heo local_irq_save(*flags); 1077bbb68dfaSTejun Heo 107836e227d2STejun Heo /* try to steal the timer if it exists */ 107936e227d2STejun Heo if (is_dwork) { 108036e227d2STejun Heo struct delayed_work *dwork = to_delayed_work(work); 108136e227d2STejun Heo 1082e0aecdd8STejun Heo /* 1083e0aecdd8STejun Heo * dwork->timer is irqsafe. If del_timer() fails, it's 1084e0aecdd8STejun Heo * guaranteed that the timer is not queued anywhere and not 1085e0aecdd8STejun Heo * running on the local CPU. 1086e0aecdd8STejun Heo */ 108736e227d2STejun Heo if (likely(del_timer(&dwork->timer))) 108836e227d2STejun Heo return 1; 108936e227d2STejun Heo } 109036e227d2STejun Heo 109136e227d2STejun Heo /* try to claim PENDING the normal way */ 1092bf4ede01STejun Heo if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) 1093bf4ede01STejun Heo return 0; 1094bf4ede01STejun Heo 1095bf4ede01STejun Heo /* 1096bf4ede01STejun Heo * The queueing is in progress, or it is already queued. Try to 1097bf4ede01STejun Heo * steal it from ->worklist without clearing WORK_STRUCT_PENDING. 1098bf4ede01STejun Heo */ 1099bf4ede01STejun Heo gcwq = get_work_gcwq(work); 1100bf4ede01STejun Heo if (!gcwq) 1101bbb68dfaSTejun Heo goto fail; 1102bf4ede01STejun Heo 1103bbb68dfaSTejun Heo spin_lock(&gcwq->lock); 1104bf4ede01STejun Heo if (!list_empty(&work->entry)) { 1105bf4ede01STejun Heo /* 1106bf4ede01STejun Heo * This work is queued, but perhaps we locked the wrong gcwq. 1107bf4ede01STejun Heo * In that case we must see the new value after rmb(), see 1108bf4ede01STejun Heo * insert_work()->wmb(). 1109bf4ede01STejun Heo */ 1110bf4ede01STejun Heo smp_rmb(); 1111bf4ede01STejun Heo if (gcwq == get_work_gcwq(work)) { 1112bf4ede01STejun Heo debug_work_deactivate(work); 11133aa62497SLai Jiangshan 11143aa62497SLai Jiangshan /* 11153aa62497SLai Jiangshan * A delayed work item cannot be grabbed directly 11163aa62497SLai Jiangshan * because it might have linked NO_COLOR work items 11173aa62497SLai Jiangshan * which, if left on the delayed_list, will confuse 11183aa62497SLai Jiangshan * cwq->nr_active management later on and cause 11193aa62497SLai Jiangshan * stall. Make sure the work item is activated 11203aa62497SLai Jiangshan * before grabbing. 11213aa62497SLai Jiangshan */ 11223aa62497SLai Jiangshan if (*work_data_bits(work) & WORK_STRUCT_DELAYED) 11233aa62497SLai Jiangshan cwq_activate_delayed_work(work); 11243aa62497SLai Jiangshan 1125bf4ede01STejun Heo list_del_init(&work->entry); 1126bf4ede01STejun Heo cwq_dec_nr_in_flight(get_work_cwq(work), 1127b3f9f405SLai Jiangshan get_work_color(work)); 112836e227d2STejun Heo 1129bbb68dfaSTejun Heo spin_unlock(&gcwq->lock); 113036e227d2STejun Heo return 1; 1131bf4ede01STejun Heo } 1132bf4ede01STejun Heo } 1133bbb68dfaSTejun Heo spin_unlock(&gcwq->lock); 1134bbb68dfaSTejun Heo fail: 1135bbb68dfaSTejun Heo local_irq_restore(*flags); 1136bbb68dfaSTejun Heo if (work_is_canceling(work)) 1137bbb68dfaSTejun Heo return -ENOENT; 1138bbb68dfaSTejun Heo cpu_relax(); 113936e227d2STejun Heo return -EAGAIN; 1140bf4ede01STejun Heo } 1141bf4ede01STejun Heo 1142bf4ede01STejun Heo /** 11437e11629dSTejun Heo * insert_work - insert a work into gcwq 11444690c4abSTejun Heo * @cwq: cwq @work belongs to 11454690c4abSTejun Heo * @work: work to insert 11464690c4abSTejun Heo * @head: insertion point 11474690c4abSTejun Heo * @extra_flags: extra WORK_STRUCT_* flags to set 11484690c4abSTejun Heo * 11497e11629dSTejun Heo * Insert @work which belongs to @cwq into @gcwq after @head. 11507e11629dSTejun Heo * @extra_flags is or'd to work_struct flags. 11514690c4abSTejun Heo * 11524690c4abSTejun Heo * CONTEXT: 11538b03ae3cSTejun Heo * spin_lock_irq(gcwq->lock). 11541da177e4SLinus Torvalds */ 1155b89deed3SOleg Nesterov static void insert_work(struct cpu_workqueue_struct *cwq, 11564690c4abSTejun Heo struct work_struct *work, struct list_head *head, 11574690c4abSTejun Heo unsigned int extra_flags) 1158b89deed3SOleg Nesterov { 115963d95a91STejun Heo struct worker_pool *pool = cwq->pool; 1160e1d8aa9fSFrederic Weisbecker 11614690c4abSTejun Heo /* we own @work, set data and link */ 11627a22ad75STejun Heo set_work_cwq(work, cwq, extra_flags); 11634690c4abSTejun Heo 11646e84d644SOleg Nesterov /* 11656e84d644SOleg Nesterov * Ensure that we get the right work->data if we see the 11666e84d644SOleg Nesterov * result of list_add() below, see try_to_grab_pending(). 11676e84d644SOleg Nesterov */ 11686e84d644SOleg Nesterov smp_wmb(); 11694690c4abSTejun Heo 11701a4d9b0aSOleg Nesterov list_add_tail(&work->entry, head); 1171e22bee78STejun Heo 1172e22bee78STejun Heo /* 1173e22bee78STejun Heo * Ensure either worker_sched_deactivated() sees the above 1174e22bee78STejun Heo * list_add_tail() or we see zero nr_running to avoid workers 1175e22bee78STejun Heo * lying around lazily while there are works to be processed. 1176e22bee78STejun Heo */ 1177e22bee78STejun Heo smp_mb(); 1178e22bee78STejun Heo 117963d95a91STejun Heo if (__need_more_worker(pool)) 118063d95a91STejun Heo wake_up_worker(pool); 1181b89deed3SOleg Nesterov } 1182b89deed3SOleg Nesterov 1183c8efcc25STejun Heo /* 1184c8efcc25STejun Heo * Test whether @work is being queued from another work executing on the 1185c8efcc25STejun Heo * same workqueue. This is rather expensive and should only be used from 1186c8efcc25STejun Heo * cold paths. 1187c8efcc25STejun Heo */ 1188c8efcc25STejun Heo static bool is_chained_work(struct workqueue_struct *wq) 1189c8efcc25STejun Heo { 1190c8efcc25STejun Heo unsigned long flags; 1191c8efcc25STejun Heo unsigned int cpu; 1192c8efcc25STejun Heo 1193c8efcc25STejun Heo for_each_gcwq_cpu(cpu) { 1194c9e7cf27STejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 1195c9e7cf27STejun Heo struct worker_pool *pool = cwq->pool; 1196c9e7cf27STejun Heo struct global_cwq *gcwq = pool->gcwq; 1197c8efcc25STejun Heo struct worker *worker; 1198c8efcc25STejun Heo struct hlist_node *pos; 1199c8efcc25STejun Heo int i; 1200c8efcc25STejun Heo 1201c8efcc25STejun Heo spin_lock_irqsave(&gcwq->lock, flags); 1202c9e7cf27STejun Heo for_each_busy_worker(worker, i, pos, pool) { 1203c8efcc25STejun Heo if (worker->task != current) 1204c8efcc25STejun Heo continue; 1205c8efcc25STejun Heo spin_unlock_irqrestore(&gcwq->lock, flags); 1206c8efcc25STejun Heo /* 1207c8efcc25STejun Heo * I'm @worker, no locking necessary. See if @work 1208c8efcc25STejun Heo * is headed to the same workqueue. 1209c8efcc25STejun Heo */ 1210c8efcc25STejun Heo return worker->current_cwq->wq == wq; 1211c8efcc25STejun Heo } 1212c8efcc25STejun Heo spin_unlock_irqrestore(&gcwq->lock, flags); 1213c8efcc25STejun Heo } 1214c8efcc25STejun Heo return false; 1215c8efcc25STejun Heo } 1216c8efcc25STejun Heo 12174690c4abSTejun Heo static void __queue_work(unsigned int cpu, struct workqueue_struct *wq, 12181da177e4SLinus Torvalds struct work_struct *work) 12191da177e4SLinus Torvalds { 1220502ca9d8STejun Heo struct global_cwq *gcwq; 1221502ca9d8STejun Heo struct cpu_workqueue_struct *cwq; 12221e19ffc6STejun Heo struct list_head *worklist; 12238a2e8e5dSTejun Heo unsigned int work_flags; 1224b75cac93SJoonsoo Kim unsigned int req_cpu = cpu; 12258930cabaSTejun Heo 12268930cabaSTejun Heo /* 12278930cabaSTejun Heo * While a work item is PENDING && off queue, a task trying to 12288930cabaSTejun Heo * steal the PENDING will busy-loop waiting for it to either get 12298930cabaSTejun Heo * queued or lose PENDING. Grabbing PENDING and queueing should 12308930cabaSTejun Heo * happen with IRQ disabled. 12318930cabaSTejun Heo */ 12328930cabaSTejun Heo WARN_ON_ONCE(!irqs_disabled()); 12331da177e4SLinus Torvalds 1234dc186ad7SThomas Gleixner debug_work_activate(work); 12351e19ffc6STejun Heo 1236c8efcc25STejun Heo /* if dying, only works from the same workqueue are allowed */ 12379c5a2ba7STejun Heo if (unlikely(wq->flags & WQ_DRAINING) && 1238c8efcc25STejun Heo WARN_ON_ONCE(!is_chained_work(wq))) 1239e41e704bSTejun Heo return; 1240e41e704bSTejun Heo 1241c7fc77f7STejun Heo /* determine gcwq to use */ 1242c7fc77f7STejun Heo if (!(wq->flags & WQ_UNBOUND)) { 1243c9e7cf27STejun Heo struct worker_pool *last_pool; 1244c7fc77f7STejun Heo 124557469821STejun Heo if (cpu == WORK_CPU_UNBOUND) 1246f3421797STejun Heo cpu = raw_smp_processor_id(); 1247f3421797STejun Heo 124818aa9effSTejun Heo /* 1249dbf2576eSTejun Heo * It's multi cpu. If @work was previously on a different 1250dbf2576eSTejun Heo * cpu, it might still be running there, in which case the 1251dbf2576eSTejun Heo * work needs to be queued on that cpu to guarantee 1252dbf2576eSTejun Heo * non-reentrancy. 125318aa9effSTejun Heo */ 1254502ca9d8STejun Heo gcwq = get_gcwq(cpu); 1255c9e7cf27STejun Heo last_pool = get_work_pool(work); 1256dbf2576eSTejun Heo 1257c9e7cf27STejun Heo if (last_pool && last_pool->gcwq != gcwq) { 1258c9e7cf27STejun Heo struct global_cwq *last_gcwq = last_pool->gcwq; 125918aa9effSTejun Heo struct worker *worker; 126018aa9effSTejun Heo 12618930cabaSTejun Heo spin_lock(&last_gcwq->lock); 126218aa9effSTejun Heo 1263c9e7cf27STejun Heo worker = find_worker_executing_work(last_pool, work); 126418aa9effSTejun Heo 126518aa9effSTejun Heo if (worker && worker->current_cwq->wq == wq) 126618aa9effSTejun Heo gcwq = last_gcwq; 126718aa9effSTejun Heo else { 126818aa9effSTejun Heo /* meh... not running there, queue here */ 12698930cabaSTejun Heo spin_unlock(&last_gcwq->lock); 12708930cabaSTejun Heo spin_lock(&gcwq->lock); 127118aa9effSTejun Heo } 12728930cabaSTejun Heo } else { 12738930cabaSTejun Heo spin_lock(&gcwq->lock); 12748930cabaSTejun Heo } 1275f3421797STejun Heo } else { 1276f3421797STejun Heo gcwq = get_gcwq(WORK_CPU_UNBOUND); 12778930cabaSTejun Heo spin_lock(&gcwq->lock); 1278502ca9d8STejun Heo } 1279502ca9d8STejun Heo 1280502ca9d8STejun Heo /* gcwq determined, get cwq and queue */ 1281ec22ca5eSTejun Heo cwq = get_cwq(gcwq->pools[0].cpu, wq); 1282b75cac93SJoonsoo Kim trace_workqueue_queue_work(req_cpu, cwq, work); 1283502ca9d8STejun Heo 1284f5b2552bSDan Carpenter if (WARN_ON(!list_empty(&work->entry))) { 12858930cabaSTejun Heo spin_unlock(&gcwq->lock); 1286f5b2552bSDan Carpenter return; 1287f5b2552bSDan Carpenter } 12881e19ffc6STejun Heo 128973f53c4aSTejun Heo cwq->nr_in_flight[cwq->work_color]++; 12908a2e8e5dSTejun Heo work_flags = work_color_to_flags(cwq->work_color); 12911e19ffc6STejun Heo 12921e19ffc6STejun Heo if (likely(cwq->nr_active < cwq->max_active)) { 1293cdadf009STejun Heo trace_workqueue_activate_work(work); 12941e19ffc6STejun Heo cwq->nr_active++; 12953270476aSTejun Heo worklist = &cwq->pool->worklist; 12968a2e8e5dSTejun Heo } else { 12978a2e8e5dSTejun Heo work_flags |= WORK_STRUCT_DELAYED; 12981e19ffc6STejun Heo worklist = &cwq->delayed_works; 12998a2e8e5dSTejun Heo } 13001e19ffc6STejun Heo 13018a2e8e5dSTejun Heo insert_work(cwq, work, worklist, work_flags); 13021e19ffc6STejun Heo 13038930cabaSTejun Heo spin_unlock(&gcwq->lock); 13041da177e4SLinus Torvalds } 13051da177e4SLinus Torvalds 13060fcb78c2SRolf Eike Beer /** 1307c1a220e7SZhang Rui * queue_work_on - queue work on specific cpu 1308c1a220e7SZhang Rui * @cpu: CPU number to execute work on 1309c1a220e7SZhang Rui * @wq: workqueue to use 1310c1a220e7SZhang Rui * @work: work to queue 1311c1a220e7SZhang Rui * 1312d4283e93STejun Heo * Returns %false if @work was already on a queue, %true otherwise. 1313c1a220e7SZhang Rui * 1314c1a220e7SZhang Rui * We queue the work to a specific CPU, the caller must ensure it 1315c1a220e7SZhang Rui * can't go away. 1316c1a220e7SZhang Rui */ 1317d4283e93STejun Heo bool queue_work_on(int cpu, struct workqueue_struct *wq, 1318d4283e93STejun Heo struct work_struct *work) 1319c1a220e7SZhang Rui { 1320d4283e93STejun Heo bool ret = false; 13218930cabaSTejun Heo unsigned long flags; 13228930cabaSTejun Heo 13238930cabaSTejun Heo local_irq_save(flags); 1324c1a220e7SZhang Rui 132522df02bbSTejun Heo if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) { 13264690c4abSTejun Heo __queue_work(cpu, wq, work); 1327d4283e93STejun Heo ret = true; 1328c1a220e7SZhang Rui } 13298930cabaSTejun Heo 13308930cabaSTejun Heo local_irq_restore(flags); 1331c1a220e7SZhang Rui return ret; 1332c1a220e7SZhang Rui } 1333c1a220e7SZhang Rui EXPORT_SYMBOL_GPL(queue_work_on); 1334c1a220e7SZhang Rui 13350a13c00eSTejun Heo /** 13360a13c00eSTejun Heo * queue_work - queue work on a workqueue 13370a13c00eSTejun Heo * @wq: workqueue to use 13380a13c00eSTejun Heo * @work: work to queue 13390a13c00eSTejun Heo * 1340d4283e93STejun Heo * Returns %false if @work was already on a queue, %true otherwise. 13410a13c00eSTejun Heo * 13420a13c00eSTejun Heo * We queue the work to the CPU on which it was submitted, but if the CPU dies 13430a13c00eSTejun Heo * it can be processed by another CPU. 13440a13c00eSTejun Heo */ 1345d4283e93STejun Heo bool queue_work(struct workqueue_struct *wq, struct work_struct *work) 13460a13c00eSTejun Heo { 134757469821STejun Heo return queue_work_on(WORK_CPU_UNBOUND, wq, work); 13480a13c00eSTejun Heo } 13490a13c00eSTejun Heo EXPORT_SYMBOL_GPL(queue_work); 13500a13c00eSTejun Heo 1351d8e794dfSTejun Heo void delayed_work_timer_fn(unsigned long __data) 13521da177e4SLinus Torvalds { 135352bad64dSDavid Howells struct delayed_work *dwork = (struct delayed_work *)__data; 13547a22ad75STejun Heo struct cpu_workqueue_struct *cwq = get_work_cwq(&dwork->work); 13551da177e4SLinus Torvalds 1356e0aecdd8STejun Heo /* should have been called from irqsafe timer with irq already off */ 13571265057fSTejun Heo __queue_work(dwork->cpu, cwq->wq, &dwork->work); 13581da177e4SLinus Torvalds } 1359d8e794dfSTejun Heo EXPORT_SYMBOL_GPL(delayed_work_timer_fn); 13601da177e4SLinus Torvalds 13617beb2edfSTejun Heo static void __queue_delayed_work(int cpu, struct workqueue_struct *wq, 136252bad64dSDavid Howells struct delayed_work *dwork, unsigned long delay) 13631da177e4SLinus Torvalds { 13647beb2edfSTejun Heo struct timer_list *timer = &dwork->timer; 13657beb2edfSTejun Heo struct work_struct *work = &dwork->work; 13667beb2edfSTejun Heo unsigned int lcpu; 13671da177e4SLinus Torvalds 13687beb2edfSTejun Heo WARN_ON_ONCE(timer->function != delayed_work_timer_fn || 13697beb2edfSTejun Heo timer->data != (unsigned long)dwork); 1370fc4b514fSTejun Heo WARN_ON_ONCE(timer_pending(timer)); 1371fc4b514fSTejun Heo WARN_ON_ONCE(!list_empty(&work->entry)); 13727beb2edfSTejun Heo 13738852aac2STejun Heo /* 13748852aac2STejun Heo * If @delay is 0, queue @dwork->work immediately. This is for 13758852aac2STejun Heo * both optimization and correctness. The earliest @timer can 13768852aac2STejun Heo * expire is on the closest next tick and delayed_work users depend 13778852aac2STejun Heo * on that there's no such delay when @delay is 0. 13788852aac2STejun Heo */ 13798852aac2STejun Heo if (!delay) { 13808852aac2STejun Heo __queue_work(cpu, wq, &dwork->work); 13818852aac2STejun Heo return; 13828852aac2STejun Heo } 13838852aac2STejun Heo 13847beb2edfSTejun Heo timer_stats_timer_set_start_info(&dwork->timer); 13857beb2edfSTejun Heo 13867beb2edfSTejun Heo /* 13877beb2edfSTejun Heo * This stores cwq for the moment, for the timer_fn. Note that the 1388ec22ca5eSTejun Heo * work's pool is preserved to allow reentrance detection for 13897beb2edfSTejun Heo * delayed works. 13907beb2edfSTejun Heo */ 13917beb2edfSTejun Heo if (!(wq->flags & WQ_UNBOUND)) { 1392ec22ca5eSTejun Heo struct worker_pool *pool = get_work_pool(work); 13937beb2edfSTejun Heo 1394e42986deSJoonsoo Kim /* 1395ec22ca5eSTejun Heo * If we cannot get the last pool from @work directly, 1396e42986deSJoonsoo Kim * select the last CPU such that it avoids unnecessarily 1397e42986deSJoonsoo Kim * triggering non-reentrancy check in __queue_work(). 1398e42986deSJoonsoo Kim */ 1399e42986deSJoonsoo Kim lcpu = cpu; 1400ec22ca5eSTejun Heo if (pool) 1401ec22ca5eSTejun Heo lcpu = pool->cpu; 1402e42986deSJoonsoo Kim if (lcpu == WORK_CPU_UNBOUND) 14037beb2edfSTejun Heo lcpu = raw_smp_processor_id(); 14047beb2edfSTejun Heo } else { 14057beb2edfSTejun Heo lcpu = WORK_CPU_UNBOUND; 14061da177e4SLinus Torvalds } 14077beb2edfSTejun Heo 14087beb2edfSTejun Heo set_work_cwq(work, get_cwq(lcpu, wq), 0); 14097beb2edfSTejun Heo 14101265057fSTejun Heo dwork->cpu = cpu; 14117beb2edfSTejun Heo timer->expires = jiffies + delay; 14127beb2edfSTejun Heo 14137beb2edfSTejun Heo if (unlikely(cpu != WORK_CPU_UNBOUND)) 14147beb2edfSTejun Heo add_timer_on(timer, cpu); 14157beb2edfSTejun Heo else 14167beb2edfSTejun Heo add_timer(timer); 14177beb2edfSTejun Heo } 14181da177e4SLinus Torvalds 14190fcb78c2SRolf Eike Beer /** 14200fcb78c2SRolf Eike Beer * queue_delayed_work_on - queue work on specific CPU after delay 14210fcb78c2SRolf Eike Beer * @cpu: CPU number to execute work on 14220fcb78c2SRolf Eike Beer * @wq: workqueue to use 1423af9997e4SRandy Dunlap * @dwork: work to queue 14240fcb78c2SRolf Eike Beer * @delay: number of jiffies to wait before queueing 14250fcb78c2SRolf Eike Beer * 1426715f1300STejun Heo * Returns %false if @work was already on a queue, %true otherwise. If 1427715f1300STejun Heo * @delay is zero and @dwork is idle, it will be scheduled for immediate 1428715f1300STejun Heo * execution. 14290fcb78c2SRolf Eike Beer */ 1430d4283e93STejun Heo bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq, 143152bad64dSDavid Howells struct delayed_work *dwork, unsigned long delay) 14327a6bc1cdSVenkatesh Pallipadi { 143352bad64dSDavid Howells struct work_struct *work = &dwork->work; 1434d4283e93STejun Heo bool ret = false; 14358930cabaSTejun Heo unsigned long flags; 14368930cabaSTejun Heo 14378930cabaSTejun Heo /* read the comment in __queue_work() */ 14388930cabaSTejun Heo local_irq_save(flags); 14397a6bc1cdSVenkatesh Pallipadi 144022df02bbSTejun Heo if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) { 14417beb2edfSTejun Heo __queue_delayed_work(cpu, wq, dwork, delay); 1442d4283e93STejun Heo ret = true; 14437a6bc1cdSVenkatesh Pallipadi } 14448930cabaSTejun Heo 14458930cabaSTejun Heo local_irq_restore(flags); 14467a6bc1cdSVenkatesh Pallipadi return ret; 14477a6bc1cdSVenkatesh Pallipadi } 1448ae90dd5dSDave Jones EXPORT_SYMBOL_GPL(queue_delayed_work_on); 14491da177e4SLinus Torvalds 1450c8e55f36STejun Heo /** 14510a13c00eSTejun Heo * queue_delayed_work - queue work on a workqueue after delay 14520a13c00eSTejun Heo * @wq: workqueue to use 14530a13c00eSTejun Heo * @dwork: delayable work to queue 14540a13c00eSTejun Heo * @delay: number of jiffies to wait before queueing 14550a13c00eSTejun Heo * 1456715f1300STejun Heo * Equivalent to queue_delayed_work_on() but tries to use the local CPU. 14570a13c00eSTejun Heo */ 1458d4283e93STejun Heo bool queue_delayed_work(struct workqueue_struct *wq, 14590a13c00eSTejun Heo struct delayed_work *dwork, unsigned long delay) 14600a13c00eSTejun Heo { 146157469821STejun Heo return queue_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay); 14620a13c00eSTejun Heo } 14630a13c00eSTejun Heo EXPORT_SYMBOL_GPL(queue_delayed_work); 14640a13c00eSTejun Heo 14650a13c00eSTejun Heo /** 14668376fe22STejun Heo * mod_delayed_work_on - modify delay of or queue a delayed work on specific CPU 14678376fe22STejun Heo * @cpu: CPU number to execute work on 14688376fe22STejun Heo * @wq: workqueue to use 14698376fe22STejun Heo * @dwork: work to queue 14708376fe22STejun Heo * @delay: number of jiffies to wait before queueing 14718376fe22STejun Heo * 14728376fe22STejun Heo * If @dwork is idle, equivalent to queue_delayed_work_on(); otherwise, 14738376fe22STejun Heo * modify @dwork's timer so that it expires after @delay. If @delay is 14748376fe22STejun Heo * zero, @work is guaranteed to be scheduled immediately regardless of its 14758376fe22STejun Heo * current state. 14768376fe22STejun Heo * 14778376fe22STejun Heo * Returns %false if @dwork was idle and queued, %true if @dwork was 14788376fe22STejun Heo * pending and its timer was modified. 14798376fe22STejun Heo * 1480e0aecdd8STejun Heo * This function is safe to call from any context including IRQ handler. 14818376fe22STejun Heo * See try_to_grab_pending() for details. 14828376fe22STejun Heo */ 14838376fe22STejun Heo bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq, 14848376fe22STejun Heo struct delayed_work *dwork, unsigned long delay) 14858376fe22STejun Heo { 14868376fe22STejun Heo unsigned long flags; 14878376fe22STejun Heo int ret; 14888376fe22STejun Heo 14898376fe22STejun Heo do { 14908376fe22STejun Heo ret = try_to_grab_pending(&dwork->work, true, &flags); 14918376fe22STejun Heo } while (unlikely(ret == -EAGAIN)); 14928376fe22STejun Heo 14938376fe22STejun Heo if (likely(ret >= 0)) { 14948376fe22STejun Heo __queue_delayed_work(cpu, wq, dwork, delay); 14958376fe22STejun Heo local_irq_restore(flags); 14968376fe22STejun Heo } 14978376fe22STejun Heo 14988376fe22STejun Heo /* -ENOENT from try_to_grab_pending() becomes %true */ 14998376fe22STejun Heo return ret; 15008376fe22STejun Heo } 15018376fe22STejun Heo EXPORT_SYMBOL_GPL(mod_delayed_work_on); 15028376fe22STejun Heo 15038376fe22STejun Heo /** 15048376fe22STejun Heo * mod_delayed_work - modify delay of or queue a delayed work 15058376fe22STejun Heo * @wq: workqueue to use 15068376fe22STejun Heo * @dwork: work to queue 15078376fe22STejun Heo * @delay: number of jiffies to wait before queueing 15088376fe22STejun Heo * 15098376fe22STejun Heo * mod_delayed_work_on() on local CPU. 15108376fe22STejun Heo */ 15118376fe22STejun Heo bool mod_delayed_work(struct workqueue_struct *wq, struct delayed_work *dwork, 15128376fe22STejun Heo unsigned long delay) 15138376fe22STejun Heo { 15148376fe22STejun Heo return mod_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay); 15158376fe22STejun Heo } 15168376fe22STejun Heo EXPORT_SYMBOL_GPL(mod_delayed_work); 15178376fe22STejun Heo 15188376fe22STejun Heo /** 1519c8e55f36STejun Heo * worker_enter_idle - enter idle state 1520c8e55f36STejun Heo * @worker: worker which is entering idle state 1521c8e55f36STejun Heo * 1522c8e55f36STejun Heo * @worker is entering idle state. Update stats and idle timer if 1523c8e55f36STejun Heo * necessary. 1524c8e55f36STejun Heo * 1525c8e55f36STejun Heo * LOCKING: 1526c8e55f36STejun Heo * spin_lock_irq(gcwq->lock). 1527c8e55f36STejun Heo */ 1528c8e55f36STejun Heo static void worker_enter_idle(struct worker *worker) 15291da177e4SLinus Torvalds { 1530bd7bdd43STejun Heo struct worker_pool *pool = worker->pool; 1531c8e55f36STejun Heo 1532c8e55f36STejun Heo BUG_ON(worker->flags & WORKER_IDLE); 1533c8e55f36STejun Heo BUG_ON(!list_empty(&worker->entry) && 1534c8e55f36STejun Heo (worker->hentry.next || worker->hentry.pprev)); 1535c8e55f36STejun Heo 1536cb444766STejun Heo /* can't use worker_set_flags(), also called from start_worker() */ 1537cb444766STejun Heo worker->flags |= WORKER_IDLE; 1538bd7bdd43STejun Heo pool->nr_idle++; 1539e22bee78STejun Heo worker->last_active = jiffies; 1540c8e55f36STejun Heo 1541c8e55f36STejun Heo /* idle_list is LIFO */ 1542bd7bdd43STejun Heo list_add(&worker->entry, &pool->idle_list); 1543db7bccf4STejun Heo 154463d95a91STejun Heo if (too_many_workers(pool) && !timer_pending(&pool->idle_timer)) 1545628c78e7STejun Heo mod_timer(&pool->idle_timer, jiffies + IDLE_WORKER_TIMEOUT); 1546cb444766STejun Heo 1547544ecf31STejun Heo /* 1548628c78e7STejun Heo * Sanity check nr_running. Because gcwq_unbind_fn() releases 1549628c78e7STejun Heo * gcwq->lock between setting %WORKER_UNBOUND and zapping 1550628c78e7STejun Heo * nr_running, the warning may trigger spuriously. Check iff 1551628c78e7STejun Heo * unbind is not in progress. 1552544ecf31STejun Heo */ 155324647570STejun Heo WARN_ON_ONCE(!(pool->flags & POOL_DISASSOCIATED) && 1554bd7bdd43STejun Heo pool->nr_workers == pool->nr_idle && 155563d95a91STejun Heo atomic_read(get_pool_nr_running(pool))); 1556c8e55f36STejun Heo } 1557c8e55f36STejun Heo 1558c8e55f36STejun Heo /** 1559c8e55f36STejun Heo * worker_leave_idle - leave idle state 1560c8e55f36STejun Heo * @worker: worker which is leaving idle state 1561c8e55f36STejun Heo * 1562c8e55f36STejun Heo * @worker is leaving idle state. Update stats. 1563c8e55f36STejun Heo * 1564c8e55f36STejun Heo * LOCKING: 1565c8e55f36STejun Heo * spin_lock_irq(gcwq->lock). 1566c8e55f36STejun Heo */ 1567c8e55f36STejun Heo static void worker_leave_idle(struct worker *worker) 1568c8e55f36STejun Heo { 1569bd7bdd43STejun Heo struct worker_pool *pool = worker->pool; 1570c8e55f36STejun Heo 1571c8e55f36STejun Heo BUG_ON(!(worker->flags & WORKER_IDLE)); 1572d302f017STejun Heo worker_clr_flags(worker, WORKER_IDLE); 1573bd7bdd43STejun Heo pool->nr_idle--; 1574c8e55f36STejun Heo list_del_init(&worker->entry); 1575c8e55f36STejun Heo } 1576c8e55f36STejun Heo 1577e22bee78STejun Heo /** 1578e22bee78STejun Heo * worker_maybe_bind_and_lock - bind worker to its cpu if possible and lock gcwq 1579e22bee78STejun Heo * @worker: self 1580e22bee78STejun Heo * 1581e22bee78STejun Heo * Works which are scheduled while the cpu is online must at least be 1582e22bee78STejun Heo * scheduled to a worker which is bound to the cpu so that if they are 1583e22bee78STejun Heo * flushed from cpu callbacks while cpu is going down, they are 1584e22bee78STejun Heo * guaranteed to execute on the cpu. 1585e22bee78STejun Heo * 1586e22bee78STejun Heo * This function is to be used by rogue workers and rescuers to bind 1587e22bee78STejun Heo * themselves to the target cpu and may race with cpu going down or 1588e22bee78STejun Heo * coming online. kthread_bind() can't be used because it may put the 1589e22bee78STejun Heo * worker to already dead cpu and set_cpus_allowed_ptr() can't be used 1590e22bee78STejun Heo * verbatim as it's best effort and blocking and gcwq may be 1591e22bee78STejun Heo * [dis]associated in the meantime. 1592e22bee78STejun Heo * 1593f2d5a0eeSTejun Heo * This function tries set_cpus_allowed() and locks gcwq and verifies the 159424647570STejun Heo * binding against %POOL_DISASSOCIATED which is set during 1595f2d5a0eeSTejun Heo * %CPU_DOWN_PREPARE and cleared during %CPU_ONLINE, so if the worker 1596f2d5a0eeSTejun Heo * enters idle state or fetches works without dropping lock, it can 1597f2d5a0eeSTejun Heo * guarantee the scheduling requirement described in the first paragraph. 1598e22bee78STejun Heo * 1599e22bee78STejun Heo * CONTEXT: 1600e22bee78STejun Heo * Might sleep. Called without any lock but returns with gcwq->lock 1601e22bee78STejun Heo * held. 1602e22bee78STejun Heo * 1603e22bee78STejun Heo * RETURNS: 1604e22bee78STejun Heo * %true if the associated gcwq is online (@worker is successfully 1605e22bee78STejun Heo * bound), %false if offline. 1606e22bee78STejun Heo */ 1607e22bee78STejun Heo static bool worker_maybe_bind_and_lock(struct worker *worker) 1608972fa1c5SNamhyung Kim __acquires(&gcwq->lock) 1609e22bee78STejun Heo { 161024647570STejun Heo struct worker_pool *pool = worker->pool; 161124647570STejun Heo struct global_cwq *gcwq = pool->gcwq; 1612e22bee78STejun Heo struct task_struct *task = worker->task; 1613e22bee78STejun Heo 1614e22bee78STejun Heo while (true) { 1615e22bee78STejun Heo /* 1616e22bee78STejun Heo * The following call may fail, succeed or succeed 1617e22bee78STejun Heo * without actually migrating the task to the cpu if 1618e22bee78STejun Heo * it races with cpu hotunplug operation. Verify 161924647570STejun Heo * against POOL_DISASSOCIATED. 1620e22bee78STejun Heo */ 162124647570STejun Heo if (!(pool->flags & POOL_DISASSOCIATED)) 1622ec22ca5eSTejun Heo set_cpus_allowed_ptr(task, get_cpu_mask(pool->cpu)); 1623e22bee78STejun Heo 1624e22bee78STejun Heo spin_lock_irq(&gcwq->lock); 162524647570STejun Heo if (pool->flags & POOL_DISASSOCIATED) 1626e22bee78STejun Heo return false; 1627ec22ca5eSTejun Heo if (task_cpu(task) == pool->cpu && 1628e22bee78STejun Heo cpumask_equal(¤t->cpus_allowed, 1629ec22ca5eSTejun Heo get_cpu_mask(pool->cpu))) 1630e22bee78STejun Heo return true; 1631e22bee78STejun Heo spin_unlock_irq(&gcwq->lock); 1632e22bee78STejun Heo 16335035b20fSTejun Heo /* 16345035b20fSTejun Heo * We've raced with CPU hot[un]plug. Give it a breather 16355035b20fSTejun Heo * and retry migration. cond_resched() is required here; 16365035b20fSTejun Heo * otherwise, we might deadlock against cpu_stop trying to 16375035b20fSTejun Heo * bring down the CPU on non-preemptive kernel. 16385035b20fSTejun Heo */ 1639e22bee78STejun Heo cpu_relax(); 16405035b20fSTejun Heo cond_resched(); 1641e22bee78STejun Heo } 1642e22bee78STejun Heo } 1643e22bee78STejun Heo 1644e22bee78STejun Heo /* 1645ea1abd61SLai Jiangshan * Rebind an idle @worker to its CPU. worker_thread() will test 16465f7dabfdSLai Jiangshan * list_empty(@worker->entry) before leaving idle and call this function. 164725511a47STejun Heo */ 164825511a47STejun Heo static void idle_worker_rebind(struct worker *worker) 164925511a47STejun Heo { 165025511a47STejun Heo struct global_cwq *gcwq = worker->pool->gcwq; 165125511a47STejun Heo 16525f7dabfdSLai Jiangshan /* CPU may go down again inbetween, clear UNBOUND only on success */ 16535f7dabfdSLai Jiangshan if (worker_maybe_bind_and_lock(worker)) 16545f7dabfdSLai Jiangshan worker_clr_flags(worker, WORKER_UNBOUND); 165525511a47STejun Heo 1656ea1abd61SLai Jiangshan /* rebind complete, become available again */ 1657ea1abd61SLai Jiangshan list_add(&worker->entry, &worker->pool->idle_list); 1658ea1abd61SLai Jiangshan spin_unlock_irq(&gcwq->lock); 165925511a47STejun Heo } 166025511a47STejun Heo 166125511a47STejun Heo /* 166225511a47STejun Heo * Function for @worker->rebind.work used to rebind unbound busy workers to 1663403c821dSTejun Heo * the associated cpu which is coming back online. This is scheduled by 1664403c821dSTejun Heo * cpu up but can race with other cpu hotplug operations and may be 1665403c821dSTejun Heo * executed twice without intervening cpu down. 1666e22bee78STejun Heo */ 166725511a47STejun Heo static void busy_worker_rebind_fn(struct work_struct *work) 1668e22bee78STejun Heo { 1669e22bee78STejun Heo struct worker *worker = container_of(work, struct worker, rebind_work); 1670bd7bdd43STejun Heo struct global_cwq *gcwq = worker->pool->gcwq; 1671e22bee78STejun Heo 1672eab6d828SLai Jiangshan if (worker_maybe_bind_and_lock(worker)) 1673eab6d828SLai Jiangshan worker_clr_flags(worker, WORKER_UNBOUND); 1674e22bee78STejun Heo 1675e22bee78STejun Heo spin_unlock_irq(&gcwq->lock); 1676e22bee78STejun Heo } 1677e22bee78STejun Heo 167825511a47STejun Heo /** 167925511a47STejun Heo * rebind_workers - rebind all workers of a gcwq to the associated CPU 168025511a47STejun Heo * @gcwq: gcwq of interest 168125511a47STejun Heo * 168225511a47STejun Heo * @gcwq->cpu is coming online. Rebind all workers to the CPU. Rebinding 168325511a47STejun Heo * is different for idle and busy ones. 168425511a47STejun Heo * 1685ea1abd61SLai Jiangshan * Idle ones will be removed from the idle_list and woken up. They will 1686ea1abd61SLai Jiangshan * add themselves back after completing rebind. This ensures that the 1687ea1abd61SLai Jiangshan * idle_list doesn't contain any unbound workers when re-bound busy workers 1688ea1abd61SLai Jiangshan * try to perform local wake-ups for concurrency management. 168925511a47STejun Heo * 1690ea1abd61SLai Jiangshan * Busy workers can rebind after they finish their current work items. 1691ea1abd61SLai Jiangshan * Queueing the rebind work item at the head of the scheduled list is 1692ea1abd61SLai Jiangshan * enough. Note that nr_running will be properly bumped as busy workers 1693ea1abd61SLai Jiangshan * rebind. 169425511a47STejun Heo * 1695ea1abd61SLai Jiangshan * On return, all non-manager workers are scheduled for rebind - see 1696ea1abd61SLai Jiangshan * manage_workers() for the manager special case. Any idle worker 1697ea1abd61SLai Jiangshan * including the manager will not appear on @idle_list until rebind is 1698ea1abd61SLai Jiangshan * complete, making local wake-ups safe. 169925511a47STejun Heo */ 170025511a47STejun Heo static void rebind_workers(struct global_cwq *gcwq) 170125511a47STejun Heo { 170225511a47STejun Heo struct worker_pool *pool; 1703ea1abd61SLai Jiangshan struct worker *worker, *n; 170425511a47STejun Heo struct hlist_node *pos; 170525511a47STejun Heo int i; 170625511a47STejun Heo 170725511a47STejun Heo lockdep_assert_held(&gcwq->lock); 170825511a47STejun Heo 170925511a47STejun Heo for_each_worker_pool(pool, gcwq) 1710b2eb83d1SLai Jiangshan lockdep_assert_held(&pool->assoc_mutex); 171125511a47STejun Heo 17125f7dabfdSLai Jiangshan /* dequeue and kick idle ones */ 171325511a47STejun Heo for_each_worker_pool(pool, gcwq) { 1714ea1abd61SLai Jiangshan list_for_each_entry_safe(worker, n, &pool->idle_list, entry) { 1715ea1abd61SLai Jiangshan /* 1716ea1abd61SLai Jiangshan * idle workers should be off @pool->idle_list 1717ea1abd61SLai Jiangshan * until rebind is complete to avoid receiving 1718ea1abd61SLai Jiangshan * premature local wake-ups. 1719ea1abd61SLai Jiangshan */ 1720ea1abd61SLai Jiangshan list_del_init(&worker->entry); 172125511a47STejun Heo 172225511a47STejun Heo /* 17235f7dabfdSLai Jiangshan * worker_thread() will see the above dequeuing 17245f7dabfdSLai Jiangshan * and call idle_worker_rebind(). 172525511a47STejun Heo */ 172625511a47STejun Heo wake_up_process(worker->task); 172725511a47STejun Heo } 172825511a47STejun Heo 1729ea1abd61SLai Jiangshan /* rebind busy workers */ 1730c9e7cf27STejun Heo for_each_busy_worker(worker, i, pos, pool) { 173125511a47STejun Heo struct work_struct *rebind_work = &worker->rebind_work; 1732e2b6a6d5SJoonsoo Kim struct workqueue_struct *wq; 173325511a47STejun Heo 173425511a47STejun Heo if (test_and_set_bit(WORK_STRUCT_PENDING_BIT, 173525511a47STejun Heo work_data_bits(rebind_work))) 173625511a47STejun Heo continue; 173725511a47STejun Heo 173825511a47STejun Heo debug_work_activate(rebind_work); 173990beca5dSTejun Heo 174090beca5dSTejun Heo /* 1741c9e7cf27STejun Heo * wq doesn't really matter but let's keep 1742c9e7cf27STejun Heo * @worker->pool and @cwq->pool consistent for 1743c9e7cf27STejun Heo * sanity. 174490beca5dSTejun Heo */ 1745e34cdddbSTejun Heo if (std_worker_pool_pri(worker->pool)) 1746e2b6a6d5SJoonsoo Kim wq = system_highpri_wq; 1747e2b6a6d5SJoonsoo Kim else 1748e2b6a6d5SJoonsoo Kim wq = system_wq; 1749ec58815aSTejun Heo 1750ec22ca5eSTejun Heo insert_work(get_cwq(pool->cpu, wq), rebind_work, 175125511a47STejun Heo worker->scheduled.next, 175225511a47STejun Heo work_color_to_flags(WORK_NO_COLOR)); 1753ec58815aSTejun Heo } 175425511a47STejun Heo } 1755c9e7cf27STejun Heo } 175625511a47STejun Heo 1757c34056a3STejun Heo static struct worker *alloc_worker(void) 1758c34056a3STejun Heo { 1759c34056a3STejun Heo struct worker *worker; 1760c34056a3STejun Heo 1761c34056a3STejun Heo worker = kzalloc(sizeof(*worker), GFP_KERNEL); 1762c8e55f36STejun Heo if (worker) { 1763c8e55f36STejun Heo INIT_LIST_HEAD(&worker->entry); 1764affee4b2STejun Heo INIT_LIST_HEAD(&worker->scheduled); 176525511a47STejun Heo INIT_WORK(&worker->rebind_work, busy_worker_rebind_fn); 1766e22bee78STejun Heo /* on creation a worker is in !idle && prep state */ 1767e22bee78STejun Heo worker->flags = WORKER_PREP; 1768c8e55f36STejun Heo } 1769c34056a3STejun Heo return worker; 1770c34056a3STejun Heo } 1771c34056a3STejun Heo 1772c34056a3STejun Heo /** 1773c34056a3STejun Heo * create_worker - create a new workqueue worker 177463d95a91STejun Heo * @pool: pool the new worker will belong to 1775c34056a3STejun Heo * 177663d95a91STejun Heo * Create a new worker which is bound to @pool. The returned worker 1777c34056a3STejun Heo * can be started by calling start_worker() or destroyed using 1778c34056a3STejun Heo * destroy_worker(). 1779c34056a3STejun Heo * 1780c34056a3STejun Heo * CONTEXT: 1781c34056a3STejun Heo * Might sleep. Does GFP_KERNEL allocations. 1782c34056a3STejun Heo * 1783c34056a3STejun Heo * RETURNS: 1784c34056a3STejun Heo * Pointer to the newly created worker. 1785c34056a3STejun Heo */ 1786bc2ae0f5STejun Heo static struct worker *create_worker(struct worker_pool *pool) 1787c34056a3STejun Heo { 178863d95a91STejun Heo struct global_cwq *gcwq = pool->gcwq; 1789e34cdddbSTejun Heo const char *pri = std_worker_pool_pri(pool) ? "H" : ""; 1790c34056a3STejun Heo struct worker *worker = NULL; 1791f3421797STejun Heo int id = -1; 1792c34056a3STejun Heo 17938b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 1794bd7bdd43STejun Heo while (ida_get_new(&pool->worker_ida, &id)) { 17958b03ae3cSTejun Heo spin_unlock_irq(&gcwq->lock); 1796bd7bdd43STejun Heo if (!ida_pre_get(&pool->worker_ida, GFP_KERNEL)) 1797c34056a3STejun Heo goto fail; 17988b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 1799c34056a3STejun Heo } 18008b03ae3cSTejun Heo spin_unlock_irq(&gcwq->lock); 1801c34056a3STejun Heo 1802c34056a3STejun Heo worker = alloc_worker(); 1803c34056a3STejun Heo if (!worker) 1804c34056a3STejun Heo goto fail; 1805c34056a3STejun Heo 1806bd7bdd43STejun Heo worker->pool = pool; 1807c34056a3STejun Heo worker->id = id; 1808c34056a3STejun Heo 1809ec22ca5eSTejun Heo if (pool->cpu != WORK_CPU_UNBOUND) 181094dcf29aSEric Dumazet worker->task = kthread_create_on_node(worker_thread, 1811ec22ca5eSTejun Heo worker, cpu_to_node(pool->cpu), 1812ec22ca5eSTejun Heo "kworker/%u:%d%s", pool->cpu, id, pri); 1813f3421797STejun Heo else 1814f3421797STejun Heo worker->task = kthread_create(worker_thread, worker, 18153270476aSTejun Heo "kworker/u:%d%s", id, pri); 1816c34056a3STejun Heo if (IS_ERR(worker->task)) 1817c34056a3STejun Heo goto fail; 1818c34056a3STejun Heo 1819e34cdddbSTejun Heo if (std_worker_pool_pri(pool)) 18203270476aSTejun Heo set_user_nice(worker->task, HIGHPRI_NICE_LEVEL); 18213270476aSTejun Heo 1822db7bccf4STejun Heo /* 1823bc2ae0f5STejun Heo * Determine CPU binding of the new worker depending on 182424647570STejun Heo * %POOL_DISASSOCIATED. The caller is responsible for ensuring the 1825bc2ae0f5STejun Heo * flag remains stable across this function. See the comments 1826bc2ae0f5STejun Heo * above the flag definition for details. 1827bc2ae0f5STejun Heo * 1828bc2ae0f5STejun Heo * As an unbound worker may later become a regular one if CPU comes 1829bc2ae0f5STejun Heo * online, make sure every worker has %PF_THREAD_BOUND set. 1830db7bccf4STejun Heo */ 183124647570STejun Heo if (!(pool->flags & POOL_DISASSOCIATED)) { 1832ec22ca5eSTejun Heo kthread_bind(worker->task, pool->cpu); 1833bc2ae0f5STejun Heo } else { 1834db7bccf4STejun Heo worker->task->flags |= PF_THREAD_BOUND; 1835f3421797STejun Heo worker->flags |= WORKER_UNBOUND; 1836f3421797STejun Heo } 1837c34056a3STejun Heo 1838c34056a3STejun Heo return worker; 1839c34056a3STejun Heo fail: 1840c34056a3STejun Heo if (id >= 0) { 18418b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 1842bd7bdd43STejun Heo ida_remove(&pool->worker_ida, id); 18438b03ae3cSTejun Heo spin_unlock_irq(&gcwq->lock); 1844c34056a3STejun Heo } 1845c34056a3STejun Heo kfree(worker); 1846c34056a3STejun Heo return NULL; 1847c34056a3STejun Heo } 1848c34056a3STejun Heo 1849c34056a3STejun Heo /** 1850c34056a3STejun Heo * start_worker - start a newly created worker 1851c34056a3STejun Heo * @worker: worker to start 1852c34056a3STejun Heo * 1853c8e55f36STejun Heo * Make the gcwq aware of @worker and start it. 1854c34056a3STejun Heo * 1855c34056a3STejun Heo * CONTEXT: 18568b03ae3cSTejun Heo * spin_lock_irq(gcwq->lock). 1857c34056a3STejun Heo */ 1858c34056a3STejun Heo static void start_worker(struct worker *worker) 1859c34056a3STejun Heo { 1860cb444766STejun Heo worker->flags |= WORKER_STARTED; 1861bd7bdd43STejun Heo worker->pool->nr_workers++; 1862c8e55f36STejun Heo worker_enter_idle(worker); 1863c34056a3STejun Heo wake_up_process(worker->task); 1864c34056a3STejun Heo } 1865c34056a3STejun Heo 1866c34056a3STejun Heo /** 1867c34056a3STejun Heo * destroy_worker - destroy a workqueue worker 1868c34056a3STejun Heo * @worker: worker to be destroyed 1869c34056a3STejun Heo * 1870c8e55f36STejun Heo * Destroy @worker and adjust @gcwq stats accordingly. 1871c8e55f36STejun Heo * 1872c8e55f36STejun Heo * CONTEXT: 1873c8e55f36STejun Heo * spin_lock_irq(gcwq->lock) which is released and regrabbed. 1874c34056a3STejun Heo */ 1875c34056a3STejun Heo static void destroy_worker(struct worker *worker) 1876c34056a3STejun Heo { 1877bd7bdd43STejun Heo struct worker_pool *pool = worker->pool; 1878bd7bdd43STejun Heo struct global_cwq *gcwq = pool->gcwq; 1879c34056a3STejun Heo int id = worker->id; 1880c34056a3STejun Heo 1881c34056a3STejun Heo /* sanity check frenzy */ 1882c34056a3STejun Heo BUG_ON(worker->current_work); 1883affee4b2STejun Heo BUG_ON(!list_empty(&worker->scheduled)); 1884c34056a3STejun Heo 1885c8e55f36STejun Heo if (worker->flags & WORKER_STARTED) 1886bd7bdd43STejun Heo pool->nr_workers--; 1887c8e55f36STejun Heo if (worker->flags & WORKER_IDLE) 1888bd7bdd43STejun Heo pool->nr_idle--; 1889c8e55f36STejun Heo 1890c8e55f36STejun Heo list_del_init(&worker->entry); 1891cb444766STejun Heo worker->flags |= WORKER_DIE; 1892c8e55f36STejun Heo 1893c8e55f36STejun Heo spin_unlock_irq(&gcwq->lock); 1894c8e55f36STejun Heo 1895c34056a3STejun Heo kthread_stop(worker->task); 1896c34056a3STejun Heo kfree(worker); 1897c34056a3STejun Heo 18988b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 1899bd7bdd43STejun Heo ida_remove(&pool->worker_ida, id); 1900c34056a3STejun Heo } 1901c34056a3STejun Heo 190263d95a91STejun Heo static void idle_worker_timeout(unsigned long __pool) 1903e22bee78STejun Heo { 190463d95a91STejun Heo struct worker_pool *pool = (void *)__pool; 190563d95a91STejun Heo struct global_cwq *gcwq = pool->gcwq; 1906e22bee78STejun Heo 1907e22bee78STejun Heo spin_lock_irq(&gcwq->lock); 1908e22bee78STejun Heo 190963d95a91STejun Heo if (too_many_workers(pool)) { 1910e22bee78STejun Heo struct worker *worker; 1911e22bee78STejun Heo unsigned long expires; 1912e22bee78STejun Heo 1913e22bee78STejun Heo /* idle_list is kept in LIFO order, check the last one */ 191463d95a91STejun Heo worker = list_entry(pool->idle_list.prev, struct worker, entry); 1915e22bee78STejun Heo expires = worker->last_active + IDLE_WORKER_TIMEOUT; 1916e22bee78STejun Heo 1917e22bee78STejun Heo if (time_before(jiffies, expires)) 191863d95a91STejun Heo mod_timer(&pool->idle_timer, expires); 1919e22bee78STejun Heo else { 1920e22bee78STejun Heo /* it's been idle for too long, wake up manager */ 192111ebea50STejun Heo pool->flags |= POOL_MANAGE_WORKERS; 192263d95a91STejun Heo wake_up_worker(pool); 1923e22bee78STejun Heo } 1924e22bee78STejun Heo } 1925e22bee78STejun Heo 1926e22bee78STejun Heo spin_unlock_irq(&gcwq->lock); 1927e22bee78STejun Heo } 1928e22bee78STejun Heo 1929e22bee78STejun Heo static bool send_mayday(struct work_struct *work) 1930e22bee78STejun Heo { 1931e22bee78STejun Heo struct cpu_workqueue_struct *cwq = get_work_cwq(work); 1932e22bee78STejun Heo struct workqueue_struct *wq = cwq->wq; 1933f3421797STejun Heo unsigned int cpu; 1934e22bee78STejun Heo 1935e22bee78STejun Heo if (!(wq->flags & WQ_RESCUER)) 1936e22bee78STejun Heo return false; 1937e22bee78STejun Heo 1938e22bee78STejun Heo /* mayday mayday mayday */ 1939ec22ca5eSTejun Heo cpu = cwq->pool->cpu; 1940f3421797STejun Heo /* WORK_CPU_UNBOUND can't be set in cpumask, use cpu 0 instead */ 1941f3421797STejun Heo if (cpu == WORK_CPU_UNBOUND) 1942f3421797STejun Heo cpu = 0; 1943f2e005aaSTejun Heo if (!mayday_test_and_set_cpu(cpu, wq->mayday_mask)) 1944e22bee78STejun Heo wake_up_process(wq->rescuer->task); 1945e22bee78STejun Heo return true; 1946e22bee78STejun Heo } 1947e22bee78STejun Heo 194863d95a91STejun Heo static void gcwq_mayday_timeout(unsigned long __pool) 1949e22bee78STejun Heo { 195063d95a91STejun Heo struct worker_pool *pool = (void *)__pool; 195163d95a91STejun Heo struct global_cwq *gcwq = pool->gcwq; 1952e22bee78STejun Heo struct work_struct *work; 1953e22bee78STejun Heo 1954e22bee78STejun Heo spin_lock_irq(&gcwq->lock); 1955e22bee78STejun Heo 195663d95a91STejun Heo if (need_to_create_worker(pool)) { 1957e22bee78STejun Heo /* 1958e22bee78STejun Heo * We've been trying to create a new worker but 1959e22bee78STejun Heo * haven't been successful. We might be hitting an 1960e22bee78STejun Heo * allocation deadlock. Send distress signals to 1961e22bee78STejun Heo * rescuers. 1962e22bee78STejun Heo */ 196363d95a91STejun Heo list_for_each_entry(work, &pool->worklist, entry) 1964e22bee78STejun Heo send_mayday(work); 1965e22bee78STejun Heo } 1966e22bee78STejun Heo 1967e22bee78STejun Heo spin_unlock_irq(&gcwq->lock); 1968e22bee78STejun Heo 196963d95a91STejun Heo mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INTERVAL); 1970e22bee78STejun Heo } 1971e22bee78STejun Heo 1972e22bee78STejun Heo /** 1973e22bee78STejun Heo * maybe_create_worker - create a new worker if necessary 197463d95a91STejun Heo * @pool: pool to create a new worker for 1975e22bee78STejun Heo * 197663d95a91STejun Heo * Create a new worker for @pool if necessary. @pool is guaranteed to 1977e22bee78STejun Heo * have at least one idle worker on return from this function. If 1978e22bee78STejun Heo * creating a new worker takes longer than MAYDAY_INTERVAL, mayday is 197963d95a91STejun Heo * sent to all rescuers with works scheduled on @pool to resolve 1980e22bee78STejun Heo * possible allocation deadlock. 1981e22bee78STejun Heo * 1982e22bee78STejun Heo * On return, need_to_create_worker() is guaranteed to be false and 1983e22bee78STejun Heo * may_start_working() true. 1984e22bee78STejun Heo * 1985e22bee78STejun Heo * LOCKING: 1986e22bee78STejun Heo * spin_lock_irq(gcwq->lock) which may be released and regrabbed 1987e22bee78STejun Heo * multiple times. Does GFP_KERNEL allocations. Called only from 1988e22bee78STejun Heo * manager. 1989e22bee78STejun Heo * 1990e22bee78STejun Heo * RETURNS: 1991e22bee78STejun Heo * false if no action was taken and gcwq->lock stayed locked, true 1992e22bee78STejun Heo * otherwise. 1993e22bee78STejun Heo */ 199463d95a91STejun Heo static bool maybe_create_worker(struct worker_pool *pool) 199506bd6ebfSNamhyung Kim __releases(&gcwq->lock) 199606bd6ebfSNamhyung Kim __acquires(&gcwq->lock) 1997e22bee78STejun Heo { 199863d95a91STejun Heo struct global_cwq *gcwq = pool->gcwq; 199963d95a91STejun Heo 200063d95a91STejun Heo if (!need_to_create_worker(pool)) 2001e22bee78STejun Heo return false; 2002e22bee78STejun Heo restart: 20039f9c2364STejun Heo spin_unlock_irq(&gcwq->lock); 20049f9c2364STejun Heo 2005e22bee78STejun Heo /* if we don't make progress in MAYDAY_INITIAL_TIMEOUT, call for help */ 200663d95a91STejun Heo mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INITIAL_TIMEOUT); 2007e22bee78STejun Heo 2008e22bee78STejun Heo while (true) { 2009e22bee78STejun Heo struct worker *worker; 2010e22bee78STejun Heo 2011bc2ae0f5STejun Heo worker = create_worker(pool); 2012e22bee78STejun Heo if (worker) { 201363d95a91STejun Heo del_timer_sync(&pool->mayday_timer); 2014e22bee78STejun Heo spin_lock_irq(&gcwq->lock); 2015e22bee78STejun Heo start_worker(worker); 201663d95a91STejun Heo BUG_ON(need_to_create_worker(pool)); 2017e22bee78STejun Heo return true; 2018e22bee78STejun Heo } 2019e22bee78STejun Heo 202063d95a91STejun Heo if (!need_to_create_worker(pool)) 2021e22bee78STejun Heo break; 2022e22bee78STejun Heo 2023e22bee78STejun Heo __set_current_state(TASK_INTERRUPTIBLE); 2024e22bee78STejun Heo schedule_timeout(CREATE_COOLDOWN); 20259f9c2364STejun Heo 202663d95a91STejun Heo if (!need_to_create_worker(pool)) 2027e22bee78STejun Heo break; 2028e22bee78STejun Heo } 2029e22bee78STejun Heo 203063d95a91STejun Heo del_timer_sync(&pool->mayday_timer); 2031e22bee78STejun Heo spin_lock_irq(&gcwq->lock); 203263d95a91STejun Heo if (need_to_create_worker(pool)) 2033e22bee78STejun Heo goto restart; 2034e22bee78STejun Heo return true; 2035e22bee78STejun Heo } 2036e22bee78STejun Heo 2037e22bee78STejun Heo /** 2038e22bee78STejun Heo * maybe_destroy_worker - destroy workers which have been idle for a while 203963d95a91STejun Heo * @pool: pool to destroy workers for 2040e22bee78STejun Heo * 204163d95a91STejun Heo * Destroy @pool workers which have been idle for longer than 2042e22bee78STejun Heo * IDLE_WORKER_TIMEOUT. 2043e22bee78STejun Heo * 2044e22bee78STejun Heo * LOCKING: 2045e22bee78STejun Heo * spin_lock_irq(gcwq->lock) which may be released and regrabbed 2046e22bee78STejun Heo * multiple times. Called only from manager. 2047e22bee78STejun Heo * 2048e22bee78STejun Heo * RETURNS: 2049e22bee78STejun Heo * false if no action was taken and gcwq->lock stayed locked, true 2050e22bee78STejun Heo * otherwise. 2051e22bee78STejun Heo */ 205263d95a91STejun Heo static bool maybe_destroy_workers(struct worker_pool *pool) 2053e22bee78STejun Heo { 2054e22bee78STejun Heo bool ret = false; 2055e22bee78STejun Heo 205663d95a91STejun Heo while (too_many_workers(pool)) { 2057e22bee78STejun Heo struct worker *worker; 2058e22bee78STejun Heo unsigned long expires; 2059e22bee78STejun Heo 206063d95a91STejun Heo worker = list_entry(pool->idle_list.prev, struct worker, entry); 2061e22bee78STejun Heo expires = worker->last_active + IDLE_WORKER_TIMEOUT; 2062e22bee78STejun Heo 2063e22bee78STejun Heo if (time_before(jiffies, expires)) { 206463d95a91STejun Heo mod_timer(&pool->idle_timer, expires); 2065e22bee78STejun Heo break; 2066e22bee78STejun Heo } 2067e22bee78STejun Heo 2068e22bee78STejun Heo destroy_worker(worker); 2069e22bee78STejun Heo ret = true; 2070e22bee78STejun Heo } 2071e22bee78STejun Heo 2072e22bee78STejun Heo return ret; 2073e22bee78STejun Heo } 2074e22bee78STejun Heo 2075e22bee78STejun Heo /** 2076e22bee78STejun Heo * manage_workers - manage worker pool 2077e22bee78STejun Heo * @worker: self 2078e22bee78STejun Heo * 2079e22bee78STejun Heo * Assume the manager role and manage gcwq worker pool @worker belongs 2080e22bee78STejun Heo * to. At any given time, there can be only zero or one manager per 2081e22bee78STejun Heo * gcwq. The exclusion is handled automatically by this function. 2082e22bee78STejun Heo * 2083e22bee78STejun Heo * The caller can safely start processing works on false return. On 2084e22bee78STejun Heo * true return, it's guaranteed that need_to_create_worker() is false 2085e22bee78STejun Heo * and may_start_working() is true. 2086e22bee78STejun Heo * 2087e22bee78STejun Heo * CONTEXT: 2088e22bee78STejun Heo * spin_lock_irq(gcwq->lock) which may be released and regrabbed 2089e22bee78STejun Heo * multiple times. Does GFP_KERNEL allocations. 2090e22bee78STejun Heo * 2091e22bee78STejun Heo * RETURNS: 2092e22bee78STejun Heo * false if no action was taken and gcwq->lock stayed locked, true if 2093e22bee78STejun Heo * some action was taken. 2094e22bee78STejun Heo */ 2095e22bee78STejun Heo static bool manage_workers(struct worker *worker) 2096e22bee78STejun Heo { 209763d95a91STejun Heo struct worker_pool *pool = worker->pool; 2098e22bee78STejun Heo bool ret = false; 2099e22bee78STejun Heo 2100ee378aa4SLai Jiangshan if (pool->flags & POOL_MANAGING_WORKERS) 2101e22bee78STejun Heo return ret; 2102e22bee78STejun Heo 2103552a37e9SLai Jiangshan pool->flags |= POOL_MANAGING_WORKERS; 2104ee378aa4SLai Jiangshan 2105ee378aa4SLai Jiangshan /* 2106ee378aa4SLai Jiangshan * To simplify both worker management and CPU hotplug, hold off 2107ee378aa4SLai Jiangshan * management while hotplug is in progress. CPU hotplug path can't 2108ee378aa4SLai Jiangshan * grab %POOL_MANAGING_WORKERS to achieve this because that can 2109ee378aa4SLai Jiangshan * lead to idle worker depletion (all become busy thinking someone 2110ee378aa4SLai Jiangshan * else is managing) which in turn can result in deadlock under 2111b2eb83d1SLai Jiangshan * extreme circumstances. Use @pool->assoc_mutex to synchronize 2112ee378aa4SLai Jiangshan * manager against CPU hotplug. 2113ee378aa4SLai Jiangshan * 2114b2eb83d1SLai Jiangshan * assoc_mutex would always be free unless CPU hotplug is in 2115ee378aa4SLai Jiangshan * progress. trylock first without dropping @gcwq->lock. 2116ee378aa4SLai Jiangshan */ 2117b2eb83d1SLai Jiangshan if (unlikely(!mutex_trylock(&pool->assoc_mutex))) { 2118ee378aa4SLai Jiangshan spin_unlock_irq(&pool->gcwq->lock); 2119b2eb83d1SLai Jiangshan mutex_lock(&pool->assoc_mutex); 2120ee378aa4SLai Jiangshan /* 2121ee378aa4SLai Jiangshan * CPU hotplug could have happened while we were waiting 2122b2eb83d1SLai Jiangshan * for assoc_mutex. Hotplug itself can't handle us 2123ee378aa4SLai Jiangshan * because manager isn't either on idle or busy list, and 2124ee378aa4SLai Jiangshan * @gcwq's state and ours could have deviated. 2125ee378aa4SLai Jiangshan * 2126b2eb83d1SLai Jiangshan * As hotplug is now excluded via assoc_mutex, we can 2127ee378aa4SLai Jiangshan * simply try to bind. It will succeed or fail depending 2128ee378aa4SLai Jiangshan * on @gcwq's current state. Try it and adjust 2129ee378aa4SLai Jiangshan * %WORKER_UNBOUND accordingly. 2130ee378aa4SLai Jiangshan */ 2131ee378aa4SLai Jiangshan if (worker_maybe_bind_and_lock(worker)) 2132ee378aa4SLai Jiangshan worker->flags &= ~WORKER_UNBOUND; 2133ee378aa4SLai Jiangshan else 2134ee378aa4SLai Jiangshan worker->flags |= WORKER_UNBOUND; 2135ee378aa4SLai Jiangshan 2136ee378aa4SLai Jiangshan ret = true; 2137ee378aa4SLai Jiangshan } 2138ee378aa4SLai Jiangshan 213911ebea50STejun Heo pool->flags &= ~POOL_MANAGE_WORKERS; 2140e22bee78STejun Heo 2141e22bee78STejun Heo /* 2142e22bee78STejun Heo * Destroy and then create so that may_start_working() is true 2143e22bee78STejun Heo * on return. 2144e22bee78STejun Heo */ 214563d95a91STejun Heo ret |= maybe_destroy_workers(pool); 214663d95a91STejun Heo ret |= maybe_create_worker(pool); 2147e22bee78STejun Heo 2148552a37e9SLai Jiangshan pool->flags &= ~POOL_MANAGING_WORKERS; 2149b2eb83d1SLai Jiangshan mutex_unlock(&pool->assoc_mutex); 2150e22bee78STejun Heo return ret; 2151e22bee78STejun Heo } 2152e22bee78STejun Heo 2153a62428c0STejun Heo /** 2154a62428c0STejun Heo * process_one_work - process single work 2155c34056a3STejun Heo * @worker: self 2156a62428c0STejun Heo * @work: work to process 2157a62428c0STejun Heo * 2158a62428c0STejun Heo * Process @work. This function contains all the logics necessary to 2159a62428c0STejun Heo * process a single work including synchronization against and 2160a62428c0STejun Heo * interaction with other workers on the same cpu, queueing and 2161a62428c0STejun Heo * flushing. As long as context requirement is met, any worker can 2162a62428c0STejun Heo * call this function to process a work. 2163a62428c0STejun Heo * 2164a62428c0STejun Heo * CONTEXT: 21658b03ae3cSTejun Heo * spin_lock_irq(gcwq->lock) which is released and regrabbed. 2166a62428c0STejun Heo */ 2167c34056a3STejun Heo static void process_one_work(struct worker *worker, struct work_struct *work) 216806bd6ebfSNamhyung Kim __releases(&gcwq->lock) 216906bd6ebfSNamhyung Kim __acquires(&gcwq->lock) 21701da177e4SLinus Torvalds { 21717e11629dSTejun Heo struct cpu_workqueue_struct *cwq = get_work_cwq(work); 2172bd7bdd43STejun Heo struct worker_pool *pool = worker->pool; 2173bd7bdd43STejun Heo struct global_cwq *gcwq = pool->gcwq; 2174fb0e7bebSTejun Heo bool cpu_intensive = cwq->wq->flags & WQ_CPU_INTENSIVE; 217573f53c4aSTejun Heo int work_color; 21767e11629dSTejun Heo struct worker *collision; 21774e6045f1SJohannes Berg #ifdef CONFIG_LOCKDEP 21784e6045f1SJohannes Berg /* 2179a62428c0STejun Heo * It is permissible to free the struct work_struct from 2180a62428c0STejun Heo * inside the function that is called from it, this we need to 2181a62428c0STejun Heo * take into account for lockdep too. To avoid bogus "held 2182a62428c0STejun Heo * lock freed" warnings as well as problems when looking into 2183a62428c0STejun Heo * work->lockdep_map, make a copy and use that here. 21844e6045f1SJohannes Berg */ 21854d82a1deSPeter Zijlstra struct lockdep_map lockdep_map; 21864d82a1deSPeter Zijlstra 21874d82a1deSPeter Zijlstra lockdep_copy_map(&lockdep_map, &work->lockdep_map); 21884e6045f1SJohannes Berg #endif 21896fec10a1STejun Heo /* 21906fec10a1STejun Heo * Ensure we're on the correct CPU. DISASSOCIATED test is 21916fec10a1STejun Heo * necessary to avoid spurious warnings from rescuers servicing the 219224647570STejun Heo * unbound or a disassociated pool. 21936fec10a1STejun Heo */ 21945f7dabfdSLai Jiangshan WARN_ON_ONCE(!(worker->flags & WORKER_UNBOUND) && 219524647570STejun Heo !(pool->flags & POOL_DISASSOCIATED) && 2196ec22ca5eSTejun Heo raw_smp_processor_id() != pool->cpu); 219725511a47STejun Heo 21987e11629dSTejun Heo /* 21997e11629dSTejun Heo * A single work shouldn't be executed concurrently by 22007e11629dSTejun Heo * multiple workers on a single cpu. Check whether anyone is 22017e11629dSTejun Heo * already processing the work. If so, defer the work to the 22027e11629dSTejun Heo * currently executing one. 22037e11629dSTejun Heo */ 2204c9e7cf27STejun Heo collision = find_worker_executing_work(pool, work); 22057e11629dSTejun Heo if (unlikely(collision)) { 22067e11629dSTejun Heo move_linked_works(work, &collision->scheduled, NULL); 22077e11629dSTejun Heo return; 22087e11629dSTejun Heo } 22091da177e4SLinus Torvalds 22108930cabaSTejun Heo /* claim and dequeue */ 22111da177e4SLinus Torvalds debug_work_deactivate(work); 2212c9e7cf27STejun Heo hash_add(pool->busy_hash, &worker->hentry, (unsigned long)work); 2213c34056a3STejun Heo worker->current_work = work; 2214a2c1c57bSTejun Heo worker->current_func = work->func; 22158cca0eeaSTejun Heo worker->current_cwq = cwq; 221673f53c4aSTejun Heo work_color = get_work_color(work); 22177a22ad75STejun Heo 2218a62428c0STejun Heo list_del_init(&work->entry); 2219a62428c0STejun Heo 2220649027d7STejun Heo /* 2221fb0e7bebSTejun Heo * CPU intensive works don't participate in concurrency 2222fb0e7bebSTejun Heo * management. They're the scheduler's responsibility. 2223fb0e7bebSTejun Heo */ 2224fb0e7bebSTejun Heo if (unlikely(cpu_intensive)) 2225fb0e7bebSTejun Heo worker_set_flags(worker, WORKER_CPU_INTENSIVE, true); 2226fb0e7bebSTejun Heo 2227974271c4STejun Heo /* 2228974271c4STejun Heo * Unbound gcwq isn't concurrency managed and work items should be 2229974271c4STejun Heo * executed ASAP. Wake up another worker if necessary. 2230974271c4STejun Heo */ 223163d95a91STejun Heo if ((worker->flags & WORKER_UNBOUND) && need_more_worker(pool)) 223263d95a91STejun Heo wake_up_worker(pool); 2233974271c4STejun Heo 22348930cabaSTejun Heo /* 22357c3eed5cSTejun Heo * Record the last pool and clear PENDING which should be the last 223623657bb1STejun Heo * update to @work. Also, do this inside @gcwq->lock so that 223723657bb1STejun Heo * PENDING and queued state changes happen together while IRQ is 223823657bb1STejun Heo * disabled. 22398930cabaSTejun Heo */ 22407c3eed5cSTejun Heo set_work_pool_and_clear_pending(work, pool->id); 22411da177e4SLinus Torvalds 22421da177e4SLinus Torvalds spin_unlock_irq(&gcwq->lock); 2243365970a1SDavid Howells 2244e159489bSTejun Heo lock_map_acquire_read(&cwq->wq->lockdep_map); 22453295f0efSIngo Molnar lock_map_acquire(&lockdep_map); 2246e36c886aSArjan van de Ven trace_workqueue_execute_start(work); 2247a2c1c57bSTejun Heo worker->current_func(work); 2248e36c886aSArjan van de Ven /* 2249e36c886aSArjan van de Ven * While we must be careful to not use "work" after this, the trace 2250e36c886aSArjan van de Ven * point will only record its address. 2251e36c886aSArjan van de Ven */ 2252e36c886aSArjan van de Ven trace_workqueue_execute_end(work); 22533295f0efSIngo Molnar lock_map_release(&lockdep_map); 22543295f0efSIngo Molnar lock_map_release(&cwq->wq->lockdep_map); 22551da177e4SLinus Torvalds 2256d5abe669SPeter Zijlstra if (unlikely(in_atomic() || lockdep_depth(current) > 0)) { 2257044c782cSValentin Ilie pr_err("BUG: workqueue leaked lock or atomic: %s/0x%08x/%d\n" 2258044c782cSValentin Ilie " last function: %pf\n", 2259a2c1c57bSTejun Heo current->comm, preempt_count(), task_pid_nr(current), 2260a2c1c57bSTejun Heo worker->current_func); 2261d5abe669SPeter Zijlstra debug_show_held_locks(current); 2262d5abe669SPeter Zijlstra dump_stack(); 2263d5abe669SPeter Zijlstra } 2264d5abe669SPeter Zijlstra 22658b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 2266a62428c0STejun Heo 2267fb0e7bebSTejun Heo /* clear cpu intensive status */ 2268fb0e7bebSTejun Heo if (unlikely(cpu_intensive)) 2269fb0e7bebSTejun Heo worker_clr_flags(worker, WORKER_CPU_INTENSIVE); 2270fb0e7bebSTejun Heo 2271a62428c0STejun Heo /* we're done with it, release */ 227242f8570fSSasha Levin hash_del(&worker->hentry); 2273c34056a3STejun Heo worker->current_work = NULL; 2274a2c1c57bSTejun Heo worker->current_func = NULL; 22758cca0eeaSTejun Heo worker->current_cwq = NULL; 2276b3f9f405SLai Jiangshan cwq_dec_nr_in_flight(cwq, work_color); 22771da177e4SLinus Torvalds } 22781da177e4SLinus Torvalds 2279affee4b2STejun Heo /** 2280affee4b2STejun Heo * process_scheduled_works - process scheduled works 2281affee4b2STejun Heo * @worker: self 2282affee4b2STejun Heo * 2283affee4b2STejun Heo * Process all scheduled works. Please note that the scheduled list 2284affee4b2STejun Heo * may change while processing a work, so this function repeatedly 2285affee4b2STejun Heo * fetches a work from the top and executes it. 2286affee4b2STejun Heo * 2287affee4b2STejun Heo * CONTEXT: 22888b03ae3cSTejun Heo * spin_lock_irq(gcwq->lock) which may be released and regrabbed 2289affee4b2STejun Heo * multiple times. 2290affee4b2STejun Heo */ 2291affee4b2STejun Heo static void process_scheduled_works(struct worker *worker) 22921da177e4SLinus Torvalds { 2293affee4b2STejun Heo while (!list_empty(&worker->scheduled)) { 2294affee4b2STejun Heo struct work_struct *work = list_first_entry(&worker->scheduled, 2295a62428c0STejun Heo struct work_struct, entry); 2296c34056a3STejun Heo process_one_work(worker, work); 2297a62428c0STejun Heo } 22981da177e4SLinus Torvalds } 22991da177e4SLinus Torvalds 23004690c4abSTejun Heo /** 23014690c4abSTejun Heo * worker_thread - the worker thread function 2302c34056a3STejun Heo * @__worker: self 23034690c4abSTejun Heo * 2304e22bee78STejun Heo * The gcwq worker thread function. There's a single dynamic pool of 2305e22bee78STejun Heo * these per each cpu. These workers process all works regardless of 2306e22bee78STejun Heo * their specific target workqueue. The only exception is works which 2307e22bee78STejun Heo * belong to workqueues with a rescuer which will be explained in 2308e22bee78STejun Heo * rescuer_thread(). 23094690c4abSTejun Heo */ 2310c34056a3STejun Heo static int worker_thread(void *__worker) 23111da177e4SLinus Torvalds { 2312c34056a3STejun Heo struct worker *worker = __worker; 2313bd7bdd43STejun Heo struct worker_pool *pool = worker->pool; 2314bd7bdd43STejun Heo struct global_cwq *gcwq = pool->gcwq; 23151da177e4SLinus Torvalds 2316e22bee78STejun Heo /* tell the scheduler that this is a workqueue worker */ 2317e22bee78STejun Heo worker->task->flags |= PF_WQ_WORKER; 2318c8e55f36STejun Heo woke_up: 23198b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 2320affee4b2STejun Heo 23215f7dabfdSLai Jiangshan /* we are off idle list if destruction or rebind is requested */ 23225f7dabfdSLai Jiangshan if (unlikely(list_empty(&worker->entry))) { 2323c8e55f36STejun Heo spin_unlock_irq(&gcwq->lock); 232425511a47STejun Heo 23255f7dabfdSLai Jiangshan /* if DIE is set, destruction is requested */ 232625511a47STejun Heo if (worker->flags & WORKER_DIE) { 2327e22bee78STejun Heo worker->task->flags &= ~PF_WQ_WORKER; 2328c8e55f36STejun Heo return 0; 2329c8e55f36STejun Heo } 2330c8e55f36STejun Heo 23315f7dabfdSLai Jiangshan /* otherwise, rebind */ 233225511a47STejun Heo idle_worker_rebind(worker); 233325511a47STejun Heo goto woke_up; 233425511a47STejun Heo } 233525511a47STejun Heo 2336c8e55f36STejun Heo worker_leave_idle(worker); 2337db7bccf4STejun Heo recheck: 2338e22bee78STejun Heo /* no more worker necessary? */ 233963d95a91STejun Heo if (!need_more_worker(pool)) 2340e22bee78STejun Heo goto sleep; 2341e22bee78STejun Heo 2342e22bee78STejun Heo /* do we need to manage? */ 234363d95a91STejun Heo if (unlikely(!may_start_working(pool)) && manage_workers(worker)) 2344e22bee78STejun Heo goto recheck; 2345e22bee78STejun Heo 2346c8e55f36STejun Heo /* 2347c8e55f36STejun Heo * ->scheduled list can only be filled while a worker is 2348c8e55f36STejun Heo * preparing to process a work or actually processing it. 2349c8e55f36STejun Heo * Make sure nobody diddled with it while I was sleeping. 2350c8e55f36STejun Heo */ 2351c8e55f36STejun Heo BUG_ON(!list_empty(&worker->scheduled)); 2352c8e55f36STejun Heo 2353e22bee78STejun Heo /* 2354e22bee78STejun Heo * When control reaches this point, we're guaranteed to have 2355e22bee78STejun Heo * at least one idle worker or that someone else has already 2356e22bee78STejun Heo * assumed the manager role. 2357e22bee78STejun Heo */ 2358e22bee78STejun Heo worker_clr_flags(worker, WORKER_PREP); 2359e22bee78STejun Heo 2360e22bee78STejun Heo do { 2361affee4b2STejun Heo struct work_struct *work = 2362bd7bdd43STejun Heo list_first_entry(&pool->worklist, 2363affee4b2STejun Heo struct work_struct, entry); 2364affee4b2STejun Heo 2365c8e55f36STejun Heo if (likely(!(*work_data_bits(work) & WORK_STRUCT_LINKED))) { 2366affee4b2STejun Heo /* optimization path, not strictly necessary */ 2367affee4b2STejun Heo process_one_work(worker, work); 2368affee4b2STejun Heo if (unlikely(!list_empty(&worker->scheduled))) 2369affee4b2STejun Heo process_scheduled_works(worker); 2370affee4b2STejun Heo } else { 2371c8e55f36STejun Heo move_linked_works(work, &worker->scheduled, NULL); 2372affee4b2STejun Heo process_scheduled_works(worker); 2373affee4b2STejun Heo } 237463d95a91STejun Heo } while (keep_working(pool)); 2375affee4b2STejun Heo 2376e22bee78STejun Heo worker_set_flags(worker, WORKER_PREP, false); 2377d313dd85STejun Heo sleep: 237863d95a91STejun Heo if (unlikely(need_to_manage_workers(pool)) && manage_workers(worker)) 2379e22bee78STejun Heo goto recheck; 2380d313dd85STejun Heo 2381c8e55f36STejun Heo /* 2382e22bee78STejun Heo * gcwq->lock is held and there's no work to process and no 2383e22bee78STejun Heo * need to manage, sleep. Workers are woken up only while 2384e22bee78STejun Heo * holding gcwq->lock or from local cpu, so setting the 2385e22bee78STejun Heo * current state before releasing gcwq->lock is enough to 2386e22bee78STejun Heo * prevent losing any event. 2387c8e55f36STejun Heo */ 2388c8e55f36STejun Heo worker_enter_idle(worker); 2389c8e55f36STejun Heo __set_current_state(TASK_INTERRUPTIBLE); 23908b03ae3cSTejun Heo spin_unlock_irq(&gcwq->lock); 23911da177e4SLinus Torvalds schedule(); 2392c8e55f36STejun Heo goto woke_up; 23931da177e4SLinus Torvalds } 23941da177e4SLinus Torvalds 2395e22bee78STejun Heo /** 2396e22bee78STejun Heo * rescuer_thread - the rescuer thread function 2397111c225aSTejun Heo * @__rescuer: self 2398e22bee78STejun Heo * 2399e22bee78STejun Heo * Workqueue rescuer thread function. There's one rescuer for each 2400e22bee78STejun Heo * workqueue which has WQ_RESCUER set. 2401e22bee78STejun Heo * 2402e22bee78STejun Heo * Regular work processing on a gcwq may block trying to create a new 2403e22bee78STejun Heo * worker which uses GFP_KERNEL allocation which has slight chance of 2404e22bee78STejun Heo * developing into deadlock if some works currently on the same queue 2405e22bee78STejun Heo * need to be processed to satisfy the GFP_KERNEL allocation. This is 2406e22bee78STejun Heo * the problem rescuer solves. 2407e22bee78STejun Heo * 2408e22bee78STejun Heo * When such condition is possible, the gcwq summons rescuers of all 2409e22bee78STejun Heo * workqueues which have works queued on the gcwq and let them process 2410e22bee78STejun Heo * those works so that forward progress can be guaranteed. 2411e22bee78STejun Heo * 2412e22bee78STejun Heo * This should happen rarely. 2413e22bee78STejun Heo */ 2414111c225aSTejun Heo static int rescuer_thread(void *__rescuer) 2415e22bee78STejun Heo { 2416111c225aSTejun Heo struct worker *rescuer = __rescuer; 2417111c225aSTejun Heo struct workqueue_struct *wq = rescuer->rescue_wq; 2418e22bee78STejun Heo struct list_head *scheduled = &rescuer->scheduled; 2419f3421797STejun Heo bool is_unbound = wq->flags & WQ_UNBOUND; 2420e22bee78STejun Heo unsigned int cpu; 2421e22bee78STejun Heo 2422e22bee78STejun Heo set_user_nice(current, RESCUER_NICE_LEVEL); 2423111c225aSTejun Heo 2424111c225aSTejun Heo /* 2425111c225aSTejun Heo * Mark rescuer as worker too. As WORKER_PREP is never cleared, it 2426111c225aSTejun Heo * doesn't participate in concurrency management. 2427111c225aSTejun Heo */ 2428111c225aSTejun Heo rescuer->task->flags |= PF_WQ_WORKER; 2429e22bee78STejun Heo repeat: 2430e22bee78STejun Heo set_current_state(TASK_INTERRUPTIBLE); 24311da177e4SLinus Torvalds 2432412d32e6SMike Galbraith if (kthread_should_stop()) { 2433412d32e6SMike Galbraith __set_current_state(TASK_RUNNING); 2434111c225aSTejun Heo rescuer->task->flags &= ~PF_WQ_WORKER; 2435e22bee78STejun Heo return 0; 2436412d32e6SMike Galbraith } 24371da177e4SLinus Torvalds 2438f3421797STejun Heo /* 2439f3421797STejun Heo * See whether any cpu is asking for help. Unbounded 2440f3421797STejun Heo * workqueues use cpu 0 in mayday_mask for CPU_UNBOUND. 2441f3421797STejun Heo */ 2442f2e005aaSTejun Heo for_each_mayday_cpu(cpu, wq->mayday_mask) { 2443f3421797STejun Heo unsigned int tcpu = is_unbound ? WORK_CPU_UNBOUND : cpu; 2444f3421797STejun Heo struct cpu_workqueue_struct *cwq = get_cwq(tcpu, wq); 2445bd7bdd43STejun Heo struct worker_pool *pool = cwq->pool; 2446bd7bdd43STejun Heo struct global_cwq *gcwq = pool->gcwq; 2447e22bee78STejun Heo struct work_struct *work, *n; 2448e22bee78STejun Heo 2449e22bee78STejun Heo __set_current_state(TASK_RUNNING); 2450f2e005aaSTejun Heo mayday_clear_cpu(cpu, wq->mayday_mask); 2451e22bee78STejun Heo 2452e22bee78STejun Heo /* migrate to the target cpu if possible */ 2453bd7bdd43STejun Heo rescuer->pool = pool; 2454e22bee78STejun Heo worker_maybe_bind_and_lock(rescuer); 2455e22bee78STejun Heo 2456e22bee78STejun Heo /* 2457e22bee78STejun Heo * Slurp in all works issued via this workqueue and 2458e22bee78STejun Heo * process'em. 2459e22bee78STejun Heo */ 2460e22bee78STejun Heo BUG_ON(!list_empty(&rescuer->scheduled)); 2461bd7bdd43STejun Heo list_for_each_entry_safe(work, n, &pool->worklist, entry) 2462e22bee78STejun Heo if (get_work_cwq(work) == cwq) 2463e22bee78STejun Heo move_linked_works(work, scheduled, &n); 2464e22bee78STejun Heo 2465e22bee78STejun Heo process_scheduled_works(rescuer); 24667576958aSTejun Heo 24677576958aSTejun Heo /* 24687576958aSTejun Heo * Leave this gcwq. If keep_working() is %true, notify a 24697576958aSTejun Heo * regular worker; otherwise, we end up with 0 concurrency 24707576958aSTejun Heo * and stalling the execution. 24717576958aSTejun Heo */ 247263d95a91STejun Heo if (keep_working(pool)) 247363d95a91STejun Heo wake_up_worker(pool); 24747576958aSTejun Heo 2475e22bee78STejun Heo spin_unlock_irq(&gcwq->lock); 24761da177e4SLinus Torvalds } 24771da177e4SLinus Torvalds 2478111c225aSTejun Heo /* rescuers should never participate in concurrency management */ 2479111c225aSTejun Heo WARN_ON_ONCE(!(rescuer->flags & WORKER_NOT_RUNNING)); 2480e22bee78STejun Heo schedule(); 2481e22bee78STejun Heo goto repeat; 24821da177e4SLinus Torvalds } 24831da177e4SLinus Torvalds 2484fc2e4d70SOleg Nesterov struct wq_barrier { 2485fc2e4d70SOleg Nesterov struct work_struct work; 2486fc2e4d70SOleg Nesterov struct completion done; 2487fc2e4d70SOleg Nesterov }; 2488fc2e4d70SOleg Nesterov 2489fc2e4d70SOleg Nesterov static void wq_barrier_func(struct work_struct *work) 2490fc2e4d70SOleg Nesterov { 2491fc2e4d70SOleg Nesterov struct wq_barrier *barr = container_of(work, struct wq_barrier, work); 2492fc2e4d70SOleg Nesterov complete(&barr->done); 2493fc2e4d70SOleg Nesterov } 2494fc2e4d70SOleg Nesterov 24954690c4abSTejun Heo /** 24964690c4abSTejun Heo * insert_wq_barrier - insert a barrier work 24974690c4abSTejun Heo * @cwq: cwq to insert barrier into 24984690c4abSTejun Heo * @barr: wq_barrier to insert 2499affee4b2STejun Heo * @target: target work to attach @barr to 2500affee4b2STejun Heo * @worker: worker currently executing @target, NULL if @target is not executing 25014690c4abSTejun Heo * 2502affee4b2STejun Heo * @barr is linked to @target such that @barr is completed only after 2503affee4b2STejun Heo * @target finishes execution. Please note that the ordering 2504affee4b2STejun Heo * guarantee is observed only with respect to @target and on the local 2505affee4b2STejun Heo * cpu. 2506affee4b2STejun Heo * 2507affee4b2STejun Heo * Currently, a queued barrier can't be canceled. This is because 2508affee4b2STejun Heo * try_to_grab_pending() can't determine whether the work to be 2509affee4b2STejun Heo * grabbed is at the head of the queue and thus can't clear LINKED 2510affee4b2STejun Heo * flag of the previous work while there must be a valid next work 2511affee4b2STejun Heo * after a work with LINKED flag set. 2512affee4b2STejun Heo * 2513affee4b2STejun Heo * Note that when @worker is non-NULL, @target may be modified 2514affee4b2STejun Heo * underneath us, so we can't reliably determine cwq from @target. 25154690c4abSTejun Heo * 25164690c4abSTejun Heo * CONTEXT: 25178b03ae3cSTejun Heo * spin_lock_irq(gcwq->lock). 25184690c4abSTejun Heo */ 251983c22520SOleg Nesterov static void insert_wq_barrier(struct cpu_workqueue_struct *cwq, 2520affee4b2STejun Heo struct wq_barrier *barr, 2521affee4b2STejun Heo struct work_struct *target, struct worker *worker) 2522fc2e4d70SOleg Nesterov { 2523affee4b2STejun Heo struct list_head *head; 2524affee4b2STejun Heo unsigned int linked = 0; 2525affee4b2STejun Heo 2526dc186ad7SThomas Gleixner /* 25278b03ae3cSTejun Heo * debugobject calls are safe here even with gcwq->lock locked 2528dc186ad7SThomas Gleixner * as we know for sure that this will not trigger any of the 2529dc186ad7SThomas Gleixner * checks and call back into the fixup functions where we 2530dc186ad7SThomas Gleixner * might deadlock. 2531dc186ad7SThomas Gleixner */ 2532ca1cab37SAndrew Morton INIT_WORK_ONSTACK(&barr->work, wq_barrier_func); 253322df02bbSTejun Heo __set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&barr->work)); 2534fc2e4d70SOleg Nesterov init_completion(&barr->done); 253583c22520SOleg Nesterov 2536affee4b2STejun Heo /* 2537affee4b2STejun Heo * If @target is currently being executed, schedule the 2538affee4b2STejun Heo * barrier to the worker; otherwise, put it after @target. 2539affee4b2STejun Heo */ 2540affee4b2STejun Heo if (worker) 2541affee4b2STejun Heo head = worker->scheduled.next; 2542affee4b2STejun Heo else { 2543affee4b2STejun Heo unsigned long *bits = work_data_bits(target); 2544affee4b2STejun Heo 2545affee4b2STejun Heo head = target->entry.next; 2546affee4b2STejun Heo /* there can already be other linked works, inherit and set */ 2547affee4b2STejun Heo linked = *bits & WORK_STRUCT_LINKED; 2548affee4b2STejun Heo __set_bit(WORK_STRUCT_LINKED_BIT, bits); 2549affee4b2STejun Heo } 2550affee4b2STejun Heo 2551dc186ad7SThomas Gleixner debug_work_activate(&barr->work); 2552affee4b2STejun Heo insert_work(cwq, &barr->work, head, 2553affee4b2STejun Heo work_color_to_flags(WORK_NO_COLOR) | linked); 2554fc2e4d70SOleg Nesterov } 2555fc2e4d70SOleg Nesterov 255673f53c4aSTejun Heo /** 255773f53c4aSTejun Heo * flush_workqueue_prep_cwqs - prepare cwqs for workqueue flushing 255873f53c4aSTejun Heo * @wq: workqueue being flushed 255973f53c4aSTejun Heo * @flush_color: new flush color, < 0 for no-op 256073f53c4aSTejun Heo * @work_color: new work color, < 0 for no-op 256173f53c4aSTejun Heo * 256273f53c4aSTejun Heo * Prepare cwqs for workqueue flushing. 256373f53c4aSTejun Heo * 256473f53c4aSTejun Heo * If @flush_color is non-negative, flush_color on all cwqs should be 256573f53c4aSTejun Heo * -1. If no cwq has in-flight commands at the specified color, all 256673f53c4aSTejun Heo * cwq->flush_color's stay at -1 and %false is returned. If any cwq 256773f53c4aSTejun Heo * has in flight commands, its cwq->flush_color is set to 256873f53c4aSTejun Heo * @flush_color, @wq->nr_cwqs_to_flush is updated accordingly, cwq 256973f53c4aSTejun Heo * wakeup logic is armed and %true is returned. 257073f53c4aSTejun Heo * 257173f53c4aSTejun Heo * The caller should have initialized @wq->first_flusher prior to 257273f53c4aSTejun Heo * calling this function with non-negative @flush_color. If 257373f53c4aSTejun Heo * @flush_color is negative, no flush color update is done and %false 257473f53c4aSTejun Heo * is returned. 257573f53c4aSTejun Heo * 257673f53c4aSTejun Heo * If @work_color is non-negative, all cwqs should have the same 257773f53c4aSTejun Heo * work_color which is previous to @work_color and all will be 257873f53c4aSTejun Heo * advanced to @work_color. 257973f53c4aSTejun Heo * 258073f53c4aSTejun Heo * CONTEXT: 258173f53c4aSTejun Heo * mutex_lock(wq->flush_mutex). 258273f53c4aSTejun Heo * 258373f53c4aSTejun Heo * RETURNS: 258473f53c4aSTejun Heo * %true if @flush_color >= 0 and there's something to flush. %false 258573f53c4aSTejun Heo * otherwise. 258673f53c4aSTejun Heo */ 258773f53c4aSTejun Heo static bool flush_workqueue_prep_cwqs(struct workqueue_struct *wq, 258873f53c4aSTejun Heo int flush_color, int work_color) 25891da177e4SLinus Torvalds { 259073f53c4aSTejun Heo bool wait = false; 259173f53c4aSTejun Heo unsigned int cpu; 25921da177e4SLinus Torvalds 259373f53c4aSTejun Heo if (flush_color >= 0) { 259473f53c4aSTejun Heo BUG_ON(atomic_read(&wq->nr_cwqs_to_flush)); 259573f53c4aSTejun Heo atomic_set(&wq->nr_cwqs_to_flush, 1); 2596dc186ad7SThomas Gleixner } 259714441960SOleg Nesterov 2598f3421797STejun Heo for_each_cwq_cpu(cpu, wq) { 259973f53c4aSTejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 2600bd7bdd43STejun Heo struct global_cwq *gcwq = cwq->pool->gcwq; 26011da177e4SLinus Torvalds 26028b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 260373f53c4aSTejun Heo 260473f53c4aSTejun Heo if (flush_color >= 0) { 260573f53c4aSTejun Heo BUG_ON(cwq->flush_color != -1); 260673f53c4aSTejun Heo 260773f53c4aSTejun Heo if (cwq->nr_in_flight[flush_color]) { 260873f53c4aSTejun Heo cwq->flush_color = flush_color; 260973f53c4aSTejun Heo atomic_inc(&wq->nr_cwqs_to_flush); 261073f53c4aSTejun Heo wait = true; 26111da177e4SLinus Torvalds } 261273f53c4aSTejun Heo } 261373f53c4aSTejun Heo 261473f53c4aSTejun Heo if (work_color >= 0) { 261573f53c4aSTejun Heo BUG_ON(work_color != work_next_color(cwq->work_color)); 261673f53c4aSTejun Heo cwq->work_color = work_color; 261773f53c4aSTejun Heo } 261873f53c4aSTejun Heo 26198b03ae3cSTejun Heo spin_unlock_irq(&gcwq->lock); 26201da177e4SLinus Torvalds } 26211da177e4SLinus Torvalds 262273f53c4aSTejun Heo if (flush_color >= 0 && atomic_dec_and_test(&wq->nr_cwqs_to_flush)) 262373f53c4aSTejun Heo complete(&wq->first_flusher->done); 262473f53c4aSTejun Heo 262573f53c4aSTejun Heo return wait; 262683c22520SOleg Nesterov } 26271da177e4SLinus Torvalds 26280fcb78c2SRolf Eike Beer /** 26291da177e4SLinus Torvalds * flush_workqueue - ensure that any scheduled work has run to completion. 26300fcb78c2SRolf Eike Beer * @wq: workqueue to flush 26311da177e4SLinus Torvalds * 26321da177e4SLinus Torvalds * Forces execution of the workqueue and blocks until its completion. 26331da177e4SLinus Torvalds * This is typically used in driver shutdown handlers. 26341da177e4SLinus Torvalds * 2635fc2e4d70SOleg Nesterov * We sleep until all works which were queued on entry have been handled, 2636fc2e4d70SOleg Nesterov * but we are not livelocked by new incoming ones. 26371da177e4SLinus Torvalds */ 26387ad5b3a5SHarvey Harrison void flush_workqueue(struct workqueue_struct *wq) 26391da177e4SLinus Torvalds { 264073f53c4aSTejun Heo struct wq_flusher this_flusher = { 264173f53c4aSTejun Heo .list = LIST_HEAD_INIT(this_flusher.list), 264273f53c4aSTejun Heo .flush_color = -1, 264373f53c4aSTejun Heo .done = COMPLETION_INITIALIZER_ONSTACK(this_flusher.done), 264473f53c4aSTejun Heo }; 264573f53c4aSTejun Heo int next_color; 2646b1f4ec17SOleg Nesterov 26473295f0efSIngo Molnar lock_map_acquire(&wq->lockdep_map); 26483295f0efSIngo Molnar lock_map_release(&wq->lockdep_map); 264973f53c4aSTejun Heo 265073f53c4aSTejun Heo mutex_lock(&wq->flush_mutex); 265173f53c4aSTejun Heo 265273f53c4aSTejun Heo /* 265373f53c4aSTejun Heo * Start-to-wait phase 265473f53c4aSTejun Heo */ 265573f53c4aSTejun Heo next_color = work_next_color(wq->work_color); 265673f53c4aSTejun Heo 265773f53c4aSTejun Heo if (next_color != wq->flush_color) { 265873f53c4aSTejun Heo /* 265973f53c4aSTejun Heo * Color space is not full. The current work_color 266073f53c4aSTejun Heo * becomes our flush_color and work_color is advanced 266173f53c4aSTejun Heo * by one. 266273f53c4aSTejun Heo */ 266373f53c4aSTejun Heo BUG_ON(!list_empty(&wq->flusher_overflow)); 266473f53c4aSTejun Heo this_flusher.flush_color = wq->work_color; 266573f53c4aSTejun Heo wq->work_color = next_color; 266673f53c4aSTejun Heo 266773f53c4aSTejun Heo if (!wq->first_flusher) { 266873f53c4aSTejun Heo /* no flush in progress, become the first flusher */ 266973f53c4aSTejun Heo BUG_ON(wq->flush_color != this_flusher.flush_color); 267073f53c4aSTejun Heo 267173f53c4aSTejun Heo wq->first_flusher = &this_flusher; 267273f53c4aSTejun Heo 267373f53c4aSTejun Heo if (!flush_workqueue_prep_cwqs(wq, wq->flush_color, 267473f53c4aSTejun Heo wq->work_color)) { 267573f53c4aSTejun Heo /* nothing to flush, done */ 267673f53c4aSTejun Heo wq->flush_color = next_color; 267773f53c4aSTejun Heo wq->first_flusher = NULL; 267873f53c4aSTejun Heo goto out_unlock; 267973f53c4aSTejun Heo } 268073f53c4aSTejun Heo } else { 268173f53c4aSTejun Heo /* wait in queue */ 268273f53c4aSTejun Heo BUG_ON(wq->flush_color == this_flusher.flush_color); 268373f53c4aSTejun Heo list_add_tail(&this_flusher.list, &wq->flusher_queue); 268473f53c4aSTejun Heo flush_workqueue_prep_cwqs(wq, -1, wq->work_color); 268573f53c4aSTejun Heo } 268673f53c4aSTejun Heo } else { 268773f53c4aSTejun Heo /* 268873f53c4aSTejun Heo * Oops, color space is full, wait on overflow queue. 268973f53c4aSTejun Heo * The next flush completion will assign us 269073f53c4aSTejun Heo * flush_color and transfer to flusher_queue. 269173f53c4aSTejun Heo */ 269273f53c4aSTejun Heo list_add_tail(&this_flusher.list, &wq->flusher_overflow); 269373f53c4aSTejun Heo } 269473f53c4aSTejun Heo 269573f53c4aSTejun Heo mutex_unlock(&wq->flush_mutex); 269673f53c4aSTejun Heo 269773f53c4aSTejun Heo wait_for_completion(&this_flusher.done); 269873f53c4aSTejun Heo 269973f53c4aSTejun Heo /* 270073f53c4aSTejun Heo * Wake-up-and-cascade phase 270173f53c4aSTejun Heo * 270273f53c4aSTejun Heo * First flushers are responsible for cascading flushes and 270373f53c4aSTejun Heo * handling overflow. Non-first flushers can simply return. 270473f53c4aSTejun Heo */ 270573f53c4aSTejun Heo if (wq->first_flusher != &this_flusher) 270673f53c4aSTejun Heo return; 270773f53c4aSTejun Heo 270873f53c4aSTejun Heo mutex_lock(&wq->flush_mutex); 270973f53c4aSTejun Heo 27104ce48b37STejun Heo /* we might have raced, check again with mutex held */ 27114ce48b37STejun Heo if (wq->first_flusher != &this_flusher) 27124ce48b37STejun Heo goto out_unlock; 27134ce48b37STejun Heo 271473f53c4aSTejun Heo wq->first_flusher = NULL; 271573f53c4aSTejun Heo 271673f53c4aSTejun Heo BUG_ON(!list_empty(&this_flusher.list)); 271773f53c4aSTejun Heo BUG_ON(wq->flush_color != this_flusher.flush_color); 271873f53c4aSTejun Heo 271973f53c4aSTejun Heo while (true) { 272073f53c4aSTejun Heo struct wq_flusher *next, *tmp; 272173f53c4aSTejun Heo 272273f53c4aSTejun Heo /* complete all the flushers sharing the current flush color */ 272373f53c4aSTejun Heo list_for_each_entry_safe(next, tmp, &wq->flusher_queue, list) { 272473f53c4aSTejun Heo if (next->flush_color != wq->flush_color) 272573f53c4aSTejun Heo break; 272673f53c4aSTejun Heo list_del_init(&next->list); 272773f53c4aSTejun Heo complete(&next->done); 272873f53c4aSTejun Heo } 272973f53c4aSTejun Heo 273073f53c4aSTejun Heo BUG_ON(!list_empty(&wq->flusher_overflow) && 273173f53c4aSTejun Heo wq->flush_color != work_next_color(wq->work_color)); 273273f53c4aSTejun Heo 273373f53c4aSTejun Heo /* this flush_color is finished, advance by one */ 273473f53c4aSTejun Heo wq->flush_color = work_next_color(wq->flush_color); 273573f53c4aSTejun Heo 273673f53c4aSTejun Heo /* one color has been freed, handle overflow queue */ 273773f53c4aSTejun Heo if (!list_empty(&wq->flusher_overflow)) { 273873f53c4aSTejun Heo /* 273973f53c4aSTejun Heo * Assign the same color to all overflowed 274073f53c4aSTejun Heo * flushers, advance work_color and append to 274173f53c4aSTejun Heo * flusher_queue. This is the start-to-wait 274273f53c4aSTejun Heo * phase for these overflowed flushers. 274373f53c4aSTejun Heo */ 274473f53c4aSTejun Heo list_for_each_entry(tmp, &wq->flusher_overflow, list) 274573f53c4aSTejun Heo tmp->flush_color = wq->work_color; 274673f53c4aSTejun Heo 274773f53c4aSTejun Heo wq->work_color = work_next_color(wq->work_color); 274873f53c4aSTejun Heo 274973f53c4aSTejun Heo list_splice_tail_init(&wq->flusher_overflow, 275073f53c4aSTejun Heo &wq->flusher_queue); 275173f53c4aSTejun Heo flush_workqueue_prep_cwqs(wq, -1, wq->work_color); 275273f53c4aSTejun Heo } 275373f53c4aSTejun Heo 275473f53c4aSTejun Heo if (list_empty(&wq->flusher_queue)) { 275573f53c4aSTejun Heo BUG_ON(wq->flush_color != wq->work_color); 275673f53c4aSTejun Heo break; 275773f53c4aSTejun Heo } 275873f53c4aSTejun Heo 275973f53c4aSTejun Heo /* 276073f53c4aSTejun Heo * Need to flush more colors. Make the next flusher 276173f53c4aSTejun Heo * the new first flusher and arm cwqs. 276273f53c4aSTejun Heo */ 276373f53c4aSTejun Heo BUG_ON(wq->flush_color == wq->work_color); 276473f53c4aSTejun Heo BUG_ON(wq->flush_color != next->flush_color); 276573f53c4aSTejun Heo 276673f53c4aSTejun Heo list_del_init(&next->list); 276773f53c4aSTejun Heo wq->first_flusher = next; 276873f53c4aSTejun Heo 276973f53c4aSTejun Heo if (flush_workqueue_prep_cwqs(wq, wq->flush_color, -1)) 277073f53c4aSTejun Heo break; 277173f53c4aSTejun Heo 277273f53c4aSTejun Heo /* 277373f53c4aSTejun Heo * Meh... this color is already done, clear first 277473f53c4aSTejun Heo * flusher and repeat cascading. 277573f53c4aSTejun Heo */ 277673f53c4aSTejun Heo wq->first_flusher = NULL; 277773f53c4aSTejun Heo } 277873f53c4aSTejun Heo 277973f53c4aSTejun Heo out_unlock: 278073f53c4aSTejun Heo mutex_unlock(&wq->flush_mutex); 27811da177e4SLinus Torvalds } 2782ae90dd5dSDave Jones EXPORT_SYMBOL_GPL(flush_workqueue); 27831da177e4SLinus Torvalds 27849c5a2ba7STejun Heo /** 27859c5a2ba7STejun Heo * drain_workqueue - drain a workqueue 27869c5a2ba7STejun Heo * @wq: workqueue to drain 27879c5a2ba7STejun Heo * 27889c5a2ba7STejun Heo * Wait until the workqueue becomes empty. While draining is in progress, 27899c5a2ba7STejun Heo * only chain queueing is allowed. IOW, only currently pending or running 27909c5a2ba7STejun Heo * work items on @wq can queue further work items on it. @wq is flushed 27919c5a2ba7STejun Heo * repeatedly until it becomes empty. The number of flushing is detemined 27929c5a2ba7STejun Heo * by the depth of chaining and should be relatively short. Whine if it 27939c5a2ba7STejun Heo * takes too long. 27949c5a2ba7STejun Heo */ 27959c5a2ba7STejun Heo void drain_workqueue(struct workqueue_struct *wq) 27969c5a2ba7STejun Heo { 27979c5a2ba7STejun Heo unsigned int flush_cnt = 0; 27989c5a2ba7STejun Heo unsigned int cpu; 27999c5a2ba7STejun Heo 28009c5a2ba7STejun Heo /* 28019c5a2ba7STejun Heo * __queue_work() needs to test whether there are drainers, is much 28029c5a2ba7STejun Heo * hotter than drain_workqueue() and already looks at @wq->flags. 28039c5a2ba7STejun Heo * Use WQ_DRAINING so that queue doesn't have to check nr_drainers. 28049c5a2ba7STejun Heo */ 28059c5a2ba7STejun Heo spin_lock(&workqueue_lock); 28069c5a2ba7STejun Heo if (!wq->nr_drainers++) 28079c5a2ba7STejun Heo wq->flags |= WQ_DRAINING; 28089c5a2ba7STejun Heo spin_unlock(&workqueue_lock); 28099c5a2ba7STejun Heo reflush: 28109c5a2ba7STejun Heo flush_workqueue(wq); 28119c5a2ba7STejun Heo 28129c5a2ba7STejun Heo for_each_cwq_cpu(cpu, wq) { 28139c5a2ba7STejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 2814fa2563e4SThomas Tuttle bool drained; 28159c5a2ba7STejun Heo 2816bd7bdd43STejun Heo spin_lock_irq(&cwq->pool->gcwq->lock); 2817fa2563e4SThomas Tuttle drained = !cwq->nr_active && list_empty(&cwq->delayed_works); 2818bd7bdd43STejun Heo spin_unlock_irq(&cwq->pool->gcwq->lock); 2819fa2563e4SThomas Tuttle 2820fa2563e4SThomas Tuttle if (drained) 28219c5a2ba7STejun Heo continue; 28229c5a2ba7STejun Heo 28239c5a2ba7STejun Heo if (++flush_cnt == 10 || 28249c5a2ba7STejun Heo (flush_cnt % 100 == 0 && flush_cnt <= 1000)) 2825044c782cSValentin Ilie pr_warn("workqueue %s: flush on destruction isn't complete after %u tries\n", 28269c5a2ba7STejun Heo wq->name, flush_cnt); 28279c5a2ba7STejun Heo goto reflush; 28289c5a2ba7STejun Heo } 28299c5a2ba7STejun Heo 28309c5a2ba7STejun Heo spin_lock(&workqueue_lock); 28319c5a2ba7STejun Heo if (!--wq->nr_drainers) 28329c5a2ba7STejun Heo wq->flags &= ~WQ_DRAINING; 28339c5a2ba7STejun Heo spin_unlock(&workqueue_lock); 28349c5a2ba7STejun Heo } 28359c5a2ba7STejun Heo EXPORT_SYMBOL_GPL(drain_workqueue); 28369c5a2ba7STejun Heo 2837606a5020STejun Heo static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr) 2838baf59022STejun Heo { 2839baf59022STejun Heo struct worker *worker = NULL; 2840c9e7cf27STejun Heo struct worker_pool *pool; 2841baf59022STejun Heo struct global_cwq *gcwq; 2842baf59022STejun Heo struct cpu_workqueue_struct *cwq; 2843baf59022STejun Heo 2844baf59022STejun Heo might_sleep(); 2845c9e7cf27STejun Heo pool = get_work_pool(work); 2846c9e7cf27STejun Heo if (!pool) 2847baf59022STejun Heo return false; 2848c9e7cf27STejun Heo gcwq = pool->gcwq; 2849baf59022STejun Heo 2850baf59022STejun Heo spin_lock_irq(&gcwq->lock); 2851baf59022STejun Heo if (!list_empty(&work->entry)) { 2852baf59022STejun Heo /* 2853baf59022STejun Heo * See the comment near try_to_grab_pending()->smp_rmb(). 2854baf59022STejun Heo * If it was re-queued to a different gcwq under us, we 2855baf59022STejun Heo * are not going to wait. 2856baf59022STejun Heo */ 2857baf59022STejun Heo smp_rmb(); 2858baf59022STejun Heo cwq = get_work_cwq(work); 2859bd7bdd43STejun Heo if (unlikely(!cwq || gcwq != cwq->pool->gcwq)) 2860baf59022STejun Heo goto already_gone; 2861606a5020STejun Heo } else { 2862c9e7cf27STejun Heo worker = find_worker_executing_work(pool, work); 2863baf59022STejun Heo if (!worker) 2864baf59022STejun Heo goto already_gone; 2865baf59022STejun Heo cwq = worker->current_cwq; 2866606a5020STejun Heo } 2867baf59022STejun Heo 2868baf59022STejun Heo insert_wq_barrier(cwq, barr, work, worker); 2869baf59022STejun Heo spin_unlock_irq(&gcwq->lock); 2870baf59022STejun Heo 2871e159489bSTejun Heo /* 2872e159489bSTejun Heo * If @max_active is 1 or rescuer is in use, flushing another work 2873e159489bSTejun Heo * item on the same workqueue may lead to deadlock. Make sure the 2874e159489bSTejun Heo * flusher is not running on the same workqueue by verifying write 2875e159489bSTejun Heo * access. 2876e159489bSTejun Heo */ 2877e159489bSTejun Heo if (cwq->wq->saved_max_active == 1 || cwq->wq->flags & WQ_RESCUER) 2878baf59022STejun Heo lock_map_acquire(&cwq->wq->lockdep_map); 2879e159489bSTejun Heo else 2880e159489bSTejun Heo lock_map_acquire_read(&cwq->wq->lockdep_map); 2881baf59022STejun Heo lock_map_release(&cwq->wq->lockdep_map); 2882e159489bSTejun Heo 2883baf59022STejun Heo return true; 2884baf59022STejun Heo already_gone: 2885baf59022STejun Heo spin_unlock_irq(&gcwq->lock); 2886baf59022STejun Heo return false; 2887baf59022STejun Heo } 2888baf59022STejun Heo 2889db700897SOleg Nesterov /** 2890401a8d04STejun Heo * flush_work - wait for a work to finish executing the last queueing instance 2891401a8d04STejun Heo * @work: the work to flush 2892db700897SOleg Nesterov * 2893606a5020STejun Heo * Wait until @work has finished execution. @work is guaranteed to be idle 2894606a5020STejun Heo * on return if it hasn't been requeued since flush started. 2895401a8d04STejun Heo * 2896401a8d04STejun Heo * RETURNS: 2897401a8d04STejun Heo * %true if flush_work() waited for the work to finish execution, 2898401a8d04STejun Heo * %false if it was already idle. 2899db700897SOleg Nesterov */ 2900401a8d04STejun Heo bool flush_work(struct work_struct *work) 2901db700897SOleg Nesterov { 2902db700897SOleg Nesterov struct wq_barrier barr; 2903db700897SOleg Nesterov 29040976dfc1SStephen Boyd lock_map_acquire(&work->lockdep_map); 29050976dfc1SStephen Boyd lock_map_release(&work->lockdep_map); 29060976dfc1SStephen Boyd 2907606a5020STejun Heo if (start_flush_work(work, &barr)) { 2908db700897SOleg Nesterov wait_for_completion(&barr.done); 2909dc186ad7SThomas Gleixner destroy_work_on_stack(&barr.work); 2910401a8d04STejun Heo return true; 2911606a5020STejun Heo } else { 2912401a8d04STejun Heo return false; 2913db700897SOleg Nesterov } 2914606a5020STejun Heo } 2915db700897SOleg Nesterov EXPORT_SYMBOL_GPL(flush_work); 2916db700897SOleg Nesterov 291736e227d2STejun Heo static bool __cancel_work_timer(struct work_struct *work, bool is_dwork) 2918401a8d04STejun Heo { 2919bbb68dfaSTejun Heo unsigned long flags; 29201f1f642eSOleg Nesterov int ret; 29211f1f642eSOleg Nesterov 29221f1f642eSOleg Nesterov do { 2923bbb68dfaSTejun Heo ret = try_to_grab_pending(work, is_dwork, &flags); 2924bbb68dfaSTejun Heo /* 2925bbb68dfaSTejun Heo * If someone else is canceling, wait for the same event it 2926bbb68dfaSTejun Heo * would be waiting for before retrying. 2927bbb68dfaSTejun Heo */ 2928bbb68dfaSTejun Heo if (unlikely(ret == -ENOENT)) 2929606a5020STejun Heo flush_work(work); 29301f1f642eSOleg Nesterov } while (unlikely(ret < 0)); 29311f1f642eSOleg Nesterov 2932bbb68dfaSTejun Heo /* tell other tasks trying to grab @work to back off */ 2933bbb68dfaSTejun Heo mark_work_canceling(work); 2934bbb68dfaSTejun Heo local_irq_restore(flags); 2935bbb68dfaSTejun Heo 2936606a5020STejun Heo flush_work(work); 29377a22ad75STejun Heo clear_work_data(work); 29381f1f642eSOleg Nesterov return ret; 29391f1f642eSOleg Nesterov } 29401f1f642eSOleg Nesterov 29416e84d644SOleg Nesterov /** 2942401a8d04STejun Heo * cancel_work_sync - cancel a work and wait for it to finish 2943401a8d04STejun Heo * @work: the work to cancel 29446e84d644SOleg Nesterov * 2945401a8d04STejun Heo * Cancel @work and wait for its execution to finish. This function 2946401a8d04STejun Heo * can be used even if the work re-queues itself or migrates to 2947401a8d04STejun Heo * another workqueue. On return from this function, @work is 2948401a8d04STejun Heo * guaranteed to be not pending or executing on any CPU. 29491f1f642eSOleg Nesterov * 2950401a8d04STejun Heo * cancel_work_sync(&delayed_work->work) must not be used for 2951401a8d04STejun Heo * delayed_work's. Use cancel_delayed_work_sync() instead. 29526e84d644SOleg Nesterov * 2953401a8d04STejun Heo * The caller must ensure that the workqueue on which @work was last 29546e84d644SOleg Nesterov * queued can't be destroyed before this function returns. 2955401a8d04STejun Heo * 2956401a8d04STejun Heo * RETURNS: 2957401a8d04STejun Heo * %true if @work was pending, %false otherwise. 29586e84d644SOleg Nesterov */ 2959401a8d04STejun Heo bool cancel_work_sync(struct work_struct *work) 29606e84d644SOleg Nesterov { 296136e227d2STejun Heo return __cancel_work_timer(work, false); 2962b89deed3SOleg Nesterov } 296328e53bddSOleg Nesterov EXPORT_SYMBOL_GPL(cancel_work_sync); 2964b89deed3SOleg Nesterov 29656e84d644SOleg Nesterov /** 2966401a8d04STejun Heo * flush_delayed_work - wait for a dwork to finish executing the last queueing 2967401a8d04STejun Heo * @dwork: the delayed work to flush 29686e84d644SOleg Nesterov * 2969401a8d04STejun Heo * Delayed timer is cancelled and the pending work is queued for 2970401a8d04STejun Heo * immediate execution. Like flush_work(), this function only 2971401a8d04STejun Heo * considers the last queueing instance of @dwork. 29721f1f642eSOleg Nesterov * 2973401a8d04STejun Heo * RETURNS: 2974401a8d04STejun Heo * %true if flush_work() waited for the work to finish execution, 2975401a8d04STejun Heo * %false if it was already idle. 29766e84d644SOleg Nesterov */ 2977401a8d04STejun Heo bool flush_delayed_work(struct delayed_work *dwork) 2978401a8d04STejun Heo { 29798930cabaSTejun Heo local_irq_disable(); 2980401a8d04STejun Heo if (del_timer_sync(&dwork->timer)) 29811265057fSTejun Heo __queue_work(dwork->cpu, 2982401a8d04STejun Heo get_work_cwq(&dwork->work)->wq, &dwork->work); 29838930cabaSTejun Heo local_irq_enable(); 2984401a8d04STejun Heo return flush_work(&dwork->work); 2985401a8d04STejun Heo } 2986401a8d04STejun Heo EXPORT_SYMBOL(flush_delayed_work); 2987401a8d04STejun Heo 2988401a8d04STejun Heo /** 298957b30ae7STejun Heo * cancel_delayed_work - cancel a delayed work 299057b30ae7STejun Heo * @dwork: delayed_work to cancel 299109383498STejun Heo * 299257b30ae7STejun Heo * Kill off a pending delayed_work. Returns %true if @dwork was pending 299357b30ae7STejun Heo * and canceled; %false if wasn't pending. Note that the work callback 299457b30ae7STejun Heo * function may still be running on return, unless it returns %true and the 299557b30ae7STejun Heo * work doesn't re-arm itself. Explicitly flush or use 299657b30ae7STejun Heo * cancel_delayed_work_sync() to wait on it. 299709383498STejun Heo * 299857b30ae7STejun Heo * This function is safe to call from any context including IRQ handler. 299909383498STejun Heo */ 300057b30ae7STejun Heo bool cancel_delayed_work(struct delayed_work *dwork) 300109383498STejun Heo { 300257b30ae7STejun Heo unsigned long flags; 300357b30ae7STejun Heo int ret; 300457b30ae7STejun Heo 300557b30ae7STejun Heo do { 300657b30ae7STejun Heo ret = try_to_grab_pending(&dwork->work, true, &flags); 300757b30ae7STejun Heo } while (unlikely(ret == -EAGAIN)); 300857b30ae7STejun Heo 300957b30ae7STejun Heo if (unlikely(ret < 0)) 301057b30ae7STejun Heo return false; 301157b30ae7STejun Heo 30127c3eed5cSTejun Heo set_work_pool_and_clear_pending(&dwork->work, 30137c3eed5cSTejun Heo get_work_pool_id(&dwork->work)); 301457b30ae7STejun Heo local_irq_restore(flags); 3015c0158ca6SDan Magenheimer return ret; 301609383498STejun Heo } 301757b30ae7STejun Heo EXPORT_SYMBOL(cancel_delayed_work); 301809383498STejun Heo 301909383498STejun Heo /** 3020401a8d04STejun Heo * cancel_delayed_work_sync - cancel a delayed work and wait for it to finish 3021401a8d04STejun Heo * @dwork: the delayed work cancel 3022401a8d04STejun Heo * 3023401a8d04STejun Heo * This is cancel_work_sync() for delayed works. 3024401a8d04STejun Heo * 3025401a8d04STejun Heo * RETURNS: 3026401a8d04STejun Heo * %true if @dwork was pending, %false otherwise. 3027401a8d04STejun Heo */ 3028401a8d04STejun Heo bool cancel_delayed_work_sync(struct delayed_work *dwork) 30296e84d644SOleg Nesterov { 303036e227d2STejun Heo return __cancel_work_timer(&dwork->work, true); 30316e84d644SOleg Nesterov } 3032f5a421a4SOleg Nesterov EXPORT_SYMBOL(cancel_delayed_work_sync); 30331da177e4SLinus Torvalds 30340fcb78c2SRolf Eike Beer /** 3035c1a220e7SZhang Rui * schedule_work_on - put work task on a specific cpu 3036c1a220e7SZhang Rui * @cpu: cpu to put the work task on 3037c1a220e7SZhang Rui * @work: job to be done 3038c1a220e7SZhang Rui * 3039c1a220e7SZhang Rui * This puts a job on a specific cpu 3040c1a220e7SZhang Rui */ 3041d4283e93STejun Heo bool schedule_work_on(int cpu, struct work_struct *work) 3042c1a220e7SZhang Rui { 3043d320c038STejun Heo return queue_work_on(cpu, system_wq, work); 3044c1a220e7SZhang Rui } 3045c1a220e7SZhang Rui EXPORT_SYMBOL(schedule_work_on); 3046c1a220e7SZhang Rui 30470fcb78c2SRolf Eike Beer /** 3048ae90dd5dSDave Jones * schedule_work - put work task in global workqueue 30491da177e4SLinus Torvalds * @work: job to be done 30501da177e4SLinus Torvalds * 3051d4283e93STejun Heo * Returns %false if @work was already on the kernel-global workqueue and 3052d4283e93STejun Heo * %true otherwise. 305352bad64dSDavid Howells * 30540fcb78c2SRolf Eike Beer * This puts a job in the kernel-global workqueue if it was not already 30550fcb78c2SRolf Eike Beer * queued and leaves it in the same position on the kernel-global 30560fcb78c2SRolf Eike Beer * workqueue otherwise. 30571da177e4SLinus Torvalds */ 3058d4283e93STejun Heo bool schedule_work(struct work_struct *work) 30591da177e4SLinus Torvalds { 30600fcb78c2SRolf Eike Beer return queue_work(system_wq, work); 30611da177e4SLinus Torvalds } 30620fcb78c2SRolf Eike Beer EXPORT_SYMBOL(schedule_work); 30631da177e4SLinus Torvalds 30640fcb78c2SRolf Eike Beer /** 30650fcb78c2SRolf Eike Beer * schedule_delayed_work_on - queue work in global workqueue on CPU after delay 30660fcb78c2SRolf Eike Beer * @cpu: cpu to use 30670fcb78c2SRolf Eike Beer * @dwork: job to be done 30680fcb78c2SRolf Eike Beer * @delay: number of jiffies to wait 30690fcb78c2SRolf Eike Beer * 30700fcb78c2SRolf Eike Beer * After waiting for a given time this puts a job in the kernel-global 30710fcb78c2SRolf Eike Beer * workqueue on the specified CPU. 30720fcb78c2SRolf Eike Beer */ 3073d4283e93STejun Heo bool schedule_delayed_work_on(int cpu, struct delayed_work *dwork, 3074d4283e93STejun Heo unsigned long delay) 30751da177e4SLinus Torvalds { 3076d320c038STejun Heo return queue_delayed_work_on(cpu, system_wq, dwork, delay); 30771da177e4SLinus Torvalds } 3078ae90dd5dSDave Jones EXPORT_SYMBOL(schedule_delayed_work_on); 30791da177e4SLinus Torvalds 3080b6136773SAndrew Morton /** 30810a13c00eSTejun Heo * schedule_delayed_work - put work task in global workqueue after delay 30820a13c00eSTejun Heo * @dwork: job to be done 30830a13c00eSTejun Heo * @delay: number of jiffies to wait or 0 for immediate execution 30840a13c00eSTejun Heo * 30850a13c00eSTejun Heo * After waiting for a given time this puts a job in the kernel-global 30860a13c00eSTejun Heo * workqueue. 30870a13c00eSTejun Heo */ 3088d4283e93STejun Heo bool schedule_delayed_work(struct delayed_work *dwork, unsigned long delay) 30890a13c00eSTejun Heo { 30900a13c00eSTejun Heo return queue_delayed_work(system_wq, dwork, delay); 30910a13c00eSTejun Heo } 30920a13c00eSTejun Heo EXPORT_SYMBOL(schedule_delayed_work); 30930a13c00eSTejun Heo 30940a13c00eSTejun Heo /** 309531ddd871STejun Heo * schedule_on_each_cpu - execute a function synchronously on each online CPU 3096b6136773SAndrew Morton * @func: the function to call 3097b6136773SAndrew Morton * 309831ddd871STejun Heo * schedule_on_each_cpu() executes @func on each online CPU using the 309931ddd871STejun Heo * system workqueue and blocks until all CPUs have completed. 3100b6136773SAndrew Morton * schedule_on_each_cpu() is very slow. 310131ddd871STejun Heo * 310231ddd871STejun Heo * RETURNS: 310331ddd871STejun Heo * 0 on success, -errno on failure. 3104b6136773SAndrew Morton */ 310565f27f38SDavid Howells int schedule_on_each_cpu(work_func_t func) 310615316ba8SChristoph Lameter { 310715316ba8SChristoph Lameter int cpu; 310838f51568SNamhyung Kim struct work_struct __percpu *works; 310915316ba8SChristoph Lameter 3110b6136773SAndrew Morton works = alloc_percpu(struct work_struct); 3111b6136773SAndrew Morton if (!works) 311215316ba8SChristoph Lameter return -ENOMEM; 3113b6136773SAndrew Morton 311495402b38SGautham R Shenoy get_online_cpus(); 311593981800STejun Heo 311615316ba8SChristoph Lameter for_each_online_cpu(cpu) { 31179bfb1839SIngo Molnar struct work_struct *work = per_cpu_ptr(works, cpu); 31189bfb1839SIngo Molnar 31199bfb1839SIngo Molnar INIT_WORK(work, func); 31208de6d308SOleg Nesterov schedule_work_on(cpu, work); 312115316ba8SChristoph Lameter } 312293981800STejun Heo 312393981800STejun Heo for_each_online_cpu(cpu) 31248616a89aSOleg Nesterov flush_work(per_cpu_ptr(works, cpu)); 312593981800STejun Heo 312695402b38SGautham R Shenoy put_online_cpus(); 3127b6136773SAndrew Morton free_percpu(works); 312815316ba8SChristoph Lameter return 0; 312915316ba8SChristoph Lameter } 313015316ba8SChristoph Lameter 3131eef6a7d5SAlan Stern /** 3132eef6a7d5SAlan Stern * flush_scheduled_work - ensure that any scheduled work has run to completion. 3133eef6a7d5SAlan Stern * 3134eef6a7d5SAlan Stern * Forces execution of the kernel-global workqueue and blocks until its 3135eef6a7d5SAlan Stern * completion. 3136eef6a7d5SAlan Stern * 3137eef6a7d5SAlan Stern * Think twice before calling this function! It's very easy to get into 3138eef6a7d5SAlan Stern * trouble if you don't take great care. Either of the following situations 3139eef6a7d5SAlan Stern * will lead to deadlock: 3140eef6a7d5SAlan Stern * 3141eef6a7d5SAlan Stern * One of the work items currently on the workqueue needs to acquire 3142eef6a7d5SAlan Stern * a lock held by your code or its caller. 3143eef6a7d5SAlan Stern * 3144eef6a7d5SAlan Stern * Your code is running in the context of a work routine. 3145eef6a7d5SAlan Stern * 3146eef6a7d5SAlan Stern * They will be detected by lockdep when they occur, but the first might not 3147eef6a7d5SAlan Stern * occur very often. It depends on what work items are on the workqueue and 3148eef6a7d5SAlan Stern * what locks they need, which you have no control over. 3149eef6a7d5SAlan Stern * 3150eef6a7d5SAlan Stern * In most situations flushing the entire workqueue is overkill; you merely 3151eef6a7d5SAlan Stern * need to know that a particular work item isn't queued and isn't running. 3152eef6a7d5SAlan Stern * In such cases you should use cancel_delayed_work_sync() or 3153eef6a7d5SAlan Stern * cancel_work_sync() instead. 3154eef6a7d5SAlan Stern */ 31551da177e4SLinus Torvalds void flush_scheduled_work(void) 31561da177e4SLinus Torvalds { 3157d320c038STejun Heo flush_workqueue(system_wq); 31581da177e4SLinus Torvalds } 3159ae90dd5dSDave Jones EXPORT_SYMBOL(flush_scheduled_work); 31601da177e4SLinus Torvalds 31611da177e4SLinus Torvalds /** 31621fa44ecaSJames Bottomley * execute_in_process_context - reliably execute the routine with user context 31631fa44ecaSJames Bottomley * @fn: the function to execute 31641fa44ecaSJames Bottomley * @ew: guaranteed storage for the execute work structure (must 31651fa44ecaSJames Bottomley * be available when the work executes) 31661fa44ecaSJames Bottomley * 31671fa44ecaSJames Bottomley * Executes the function immediately if process context is available, 31681fa44ecaSJames Bottomley * otherwise schedules the function for delayed execution. 31691fa44ecaSJames Bottomley * 31701fa44ecaSJames Bottomley * Returns: 0 - function was executed 31711fa44ecaSJames Bottomley * 1 - function was scheduled for execution 31721fa44ecaSJames Bottomley */ 317365f27f38SDavid Howells int execute_in_process_context(work_func_t fn, struct execute_work *ew) 31741fa44ecaSJames Bottomley { 31751fa44ecaSJames Bottomley if (!in_interrupt()) { 317665f27f38SDavid Howells fn(&ew->work); 31771fa44ecaSJames Bottomley return 0; 31781fa44ecaSJames Bottomley } 31791fa44ecaSJames Bottomley 318065f27f38SDavid Howells INIT_WORK(&ew->work, fn); 31811fa44ecaSJames Bottomley schedule_work(&ew->work); 31821fa44ecaSJames Bottomley 31831fa44ecaSJames Bottomley return 1; 31841fa44ecaSJames Bottomley } 31851fa44ecaSJames Bottomley EXPORT_SYMBOL_GPL(execute_in_process_context); 31861fa44ecaSJames Bottomley 31871da177e4SLinus Torvalds int keventd_up(void) 31881da177e4SLinus Torvalds { 3189d320c038STejun Heo return system_wq != NULL; 31901da177e4SLinus Torvalds } 31911da177e4SLinus Torvalds 3192bdbc5dd7STejun Heo static int alloc_cwqs(struct workqueue_struct *wq) 31931da177e4SLinus Torvalds { 31943af24433SOleg Nesterov /* 31950f900049STejun Heo * cwqs are forced aligned according to WORK_STRUCT_FLAG_BITS. 31960f900049STejun Heo * Make sure that the alignment isn't lower than that of 31970f900049STejun Heo * unsigned long long. 31983af24433SOleg Nesterov */ 31990f900049STejun Heo const size_t size = sizeof(struct cpu_workqueue_struct); 32000f900049STejun Heo const size_t align = max_t(size_t, 1 << WORK_STRUCT_FLAG_BITS, 32010f900049STejun Heo __alignof__(unsigned long long)); 32023af24433SOleg Nesterov 3203e06ffa1eSLai Jiangshan if (!(wq->flags & WQ_UNBOUND)) 3204f3421797STejun Heo wq->cpu_wq.pcpu = __alloc_percpu(size, align); 3205931ac77eSTejun Heo else { 32060f900049STejun Heo void *ptr; 3207e1d8aa9fSFrederic Weisbecker 32080f900049STejun Heo /* 3209f3421797STejun Heo * Allocate enough room to align cwq and put an extra 3210f3421797STejun Heo * pointer at the end pointing back to the originally 3211f3421797STejun Heo * allocated pointer which will be used for free. 32120f900049STejun Heo */ 3213bdbc5dd7STejun Heo ptr = kzalloc(size + align + sizeof(void *), GFP_KERNEL); 3214bdbc5dd7STejun Heo if (ptr) { 3215bdbc5dd7STejun Heo wq->cpu_wq.single = PTR_ALIGN(ptr, align); 3216bdbc5dd7STejun Heo *(void **)(wq->cpu_wq.single + 1) = ptr; 3217bdbc5dd7STejun Heo } 32183af24433SOleg Nesterov } 32193af24433SOleg Nesterov 32200415b00dSTejun Heo /* just in case, make sure it's actually aligned */ 3221bdbc5dd7STejun Heo BUG_ON(!IS_ALIGNED(wq->cpu_wq.v, align)); 3222bdbc5dd7STejun Heo return wq->cpu_wq.v ? 0 : -ENOMEM; 32230f900049STejun Heo } 32240f900049STejun Heo 3225bdbc5dd7STejun Heo static void free_cwqs(struct workqueue_struct *wq) 322606ba38a9SOleg Nesterov { 3227e06ffa1eSLai Jiangshan if (!(wq->flags & WQ_UNBOUND)) 3228bdbc5dd7STejun Heo free_percpu(wq->cpu_wq.pcpu); 3229f3421797STejun Heo else if (wq->cpu_wq.single) { 3230f3421797STejun Heo /* the pointer to free is stored right after the cwq */ 3231f3421797STejun Heo kfree(*(void **)(wq->cpu_wq.single + 1)); 323206ba38a9SOleg Nesterov } 323306ba38a9SOleg Nesterov } 323406ba38a9SOleg Nesterov 3235f3421797STejun Heo static int wq_clamp_max_active(int max_active, unsigned int flags, 3236f3421797STejun Heo const char *name) 3237b71ab8c2STejun Heo { 3238f3421797STejun Heo int lim = flags & WQ_UNBOUND ? WQ_UNBOUND_MAX_ACTIVE : WQ_MAX_ACTIVE; 3239f3421797STejun Heo 3240f3421797STejun Heo if (max_active < 1 || max_active > lim) 3241044c782cSValentin Ilie pr_warn("workqueue: max_active %d requested for %s is out of range, clamping between %d and %d\n", 3242f3421797STejun Heo max_active, name, 1, lim); 3243b71ab8c2STejun Heo 3244f3421797STejun Heo return clamp_val(max_active, 1, lim); 3245b71ab8c2STejun Heo } 3246b71ab8c2STejun Heo 3247b196be89STejun Heo struct workqueue_struct *__alloc_workqueue_key(const char *fmt, 324897e37d7bSTejun Heo unsigned int flags, 32491e19ffc6STejun Heo int max_active, 3250eb13ba87SJohannes Berg struct lock_class_key *key, 3251b196be89STejun Heo const char *lock_name, ...) 32523af24433SOleg Nesterov { 3253b196be89STejun Heo va_list args, args1; 32543af24433SOleg Nesterov struct workqueue_struct *wq; 3255c34056a3STejun Heo unsigned int cpu; 3256b196be89STejun Heo size_t namelen; 3257b196be89STejun Heo 3258b196be89STejun Heo /* determine namelen, allocate wq and format name */ 3259b196be89STejun Heo va_start(args, lock_name); 3260b196be89STejun Heo va_copy(args1, args); 3261b196be89STejun Heo namelen = vsnprintf(NULL, 0, fmt, args) + 1; 3262b196be89STejun Heo 3263b196be89STejun Heo wq = kzalloc(sizeof(*wq) + namelen, GFP_KERNEL); 3264b196be89STejun Heo if (!wq) 3265b196be89STejun Heo goto err; 3266b196be89STejun Heo 3267b196be89STejun Heo vsnprintf(wq->name, namelen, fmt, args1); 3268b196be89STejun Heo va_end(args); 3269b196be89STejun Heo va_end(args1); 32703af24433SOleg Nesterov 3271f3421797STejun Heo /* 32726370a6adSTejun Heo * Workqueues which may be used during memory reclaim should 32736370a6adSTejun Heo * have a rescuer to guarantee forward progress. 32746370a6adSTejun Heo */ 32756370a6adSTejun Heo if (flags & WQ_MEM_RECLAIM) 32766370a6adSTejun Heo flags |= WQ_RESCUER; 32776370a6adSTejun Heo 3278d320c038STejun Heo max_active = max_active ?: WQ_DFL_ACTIVE; 3279b196be89STejun Heo max_active = wq_clamp_max_active(max_active, flags, wq->name); 32803af24433SOleg Nesterov 3281b196be89STejun Heo /* init wq */ 328297e37d7bSTejun Heo wq->flags = flags; 3283a0a1a5fdSTejun Heo wq->saved_max_active = max_active; 328473f53c4aSTejun Heo mutex_init(&wq->flush_mutex); 328573f53c4aSTejun Heo atomic_set(&wq->nr_cwqs_to_flush, 0); 328673f53c4aSTejun Heo INIT_LIST_HEAD(&wq->flusher_queue); 328773f53c4aSTejun Heo INIT_LIST_HEAD(&wq->flusher_overflow); 32883af24433SOleg Nesterov 3289eb13ba87SJohannes Berg lockdep_init_map(&wq->lockdep_map, lock_name, key, 0); 3290cce1a165SOleg Nesterov INIT_LIST_HEAD(&wq->list); 32913af24433SOleg Nesterov 3292bdbc5dd7STejun Heo if (alloc_cwqs(wq) < 0) 3293bdbc5dd7STejun Heo goto err; 3294bdbc5dd7STejun Heo 3295f3421797STejun Heo for_each_cwq_cpu(cpu, wq) { 32961537663fSTejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 32978b03ae3cSTejun Heo struct global_cwq *gcwq = get_gcwq(cpu); 32983270476aSTejun Heo int pool_idx = (bool)(flags & WQ_HIGHPRI); 32991537663fSTejun Heo 33000f900049STejun Heo BUG_ON((unsigned long)cwq & WORK_STRUCT_FLAG_MASK); 33013270476aSTejun Heo cwq->pool = &gcwq->pools[pool_idx]; 3302c34056a3STejun Heo cwq->wq = wq; 330373f53c4aSTejun Heo cwq->flush_color = -1; 33041e19ffc6STejun Heo cwq->max_active = max_active; 33051e19ffc6STejun Heo INIT_LIST_HEAD(&cwq->delayed_works); 3306e22bee78STejun Heo } 33071537663fSTejun Heo 3308e22bee78STejun Heo if (flags & WQ_RESCUER) { 3309e22bee78STejun Heo struct worker *rescuer; 3310e22bee78STejun Heo 3311f2e005aaSTejun Heo if (!alloc_mayday_mask(&wq->mayday_mask, GFP_KERNEL)) 3312e22bee78STejun Heo goto err; 3313e22bee78STejun Heo 3314e22bee78STejun Heo wq->rescuer = rescuer = alloc_worker(); 3315e22bee78STejun Heo if (!rescuer) 3316e22bee78STejun Heo goto err; 3317e22bee78STejun Heo 3318111c225aSTejun Heo rescuer->rescue_wq = wq; 3319111c225aSTejun Heo rescuer->task = kthread_create(rescuer_thread, rescuer, "%s", 3320b196be89STejun Heo wq->name); 3321e22bee78STejun Heo if (IS_ERR(rescuer->task)) 3322e22bee78STejun Heo goto err; 3323e22bee78STejun Heo 3324e22bee78STejun Heo rescuer->task->flags |= PF_THREAD_BOUND; 3325e22bee78STejun Heo wake_up_process(rescuer->task); 33263af24433SOleg Nesterov } 33271537663fSTejun Heo 33283af24433SOleg Nesterov /* 3329a0a1a5fdSTejun Heo * workqueue_lock protects global freeze state and workqueues 3330a0a1a5fdSTejun Heo * list. Grab it, set max_active accordingly and add the new 3331a0a1a5fdSTejun Heo * workqueue to workqueues list. 33323af24433SOleg Nesterov */ 33333af24433SOleg Nesterov spin_lock(&workqueue_lock); 3334a0a1a5fdSTejun Heo 333558a69cb4STejun Heo if (workqueue_freezing && wq->flags & WQ_FREEZABLE) 3336f3421797STejun Heo for_each_cwq_cpu(cpu, wq) 3337a0a1a5fdSTejun Heo get_cwq(cpu, wq)->max_active = 0; 3338a0a1a5fdSTejun Heo 33393af24433SOleg Nesterov list_add(&wq->list, &workqueues); 3340a0a1a5fdSTejun Heo 33413af24433SOleg Nesterov spin_unlock(&workqueue_lock); 33423af24433SOleg Nesterov 33433af24433SOleg Nesterov return wq; 33444690c4abSTejun Heo err: 33454690c4abSTejun Heo if (wq) { 3346bdbc5dd7STejun Heo free_cwqs(wq); 3347f2e005aaSTejun Heo free_mayday_mask(wq->mayday_mask); 3348e22bee78STejun Heo kfree(wq->rescuer); 33494690c4abSTejun Heo kfree(wq); 33503af24433SOleg Nesterov } 33514690c4abSTejun Heo return NULL; 33521da177e4SLinus Torvalds } 3353d320c038STejun Heo EXPORT_SYMBOL_GPL(__alloc_workqueue_key); 33541da177e4SLinus Torvalds 33553af24433SOleg Nesterov /** 33563af24433SOleg Nesterov * destroy_workqueue - safely terminate a workqueue 33573af24433SOleg Nesterov * @wq: target workqueue 33583af24433SOleg Nesterov * 33593af24433SOleg Nesterov * Safely destroy a workqueue. All work currently pending will be done first. 33603af24433SOleg Nesterov */ 33613af24433SOleg Nesterov void destroy_workqueue(struct workqueue_struct *wq) 33623af24433SOleg Nesterov { 3363c8e55f36STejun Heo unsigned int cpu; 33643af24433SOleg Nesterov 33659c5a2ba7STejun Heo /* drain it before proceeding with destruction */ 33669c5a2ba7STejun Heo drain_workqueue(wq); 3367c8efcc25STejun Heo 3368a0a1a5fdSTejun Heo /* 3369a0a1a5fdSTejun Heo * wq list is used to freeze wq, remove from list after 3370a0a1a5fdSTejun Heo * flushing is complete in case freeze races us. 3371a0a1a5fdSTejun Heo */ 337295402b38SGautham R Shenoy spin_lock(&workqueue_lock); 33733af24433SOleg Nesterov list_del(&wq->list); 337495402b38SGautham R Shenoy spin_unlock(&workqueue_lock); 33753af24433SOleg Nesterov 3376e22bee78STejun Heo /* sanity check */ 3377f3421797STejun Heo for_each_cwq_cpu(cpu, wq) { 337873f53c4aSTejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 337973f53c4aSTejun Heo int i; 33803af24433SOleg Nesterov 338173f53c4aSTejun Heo for (i = 0; i < WORK_NR_COLORS; i++) 338273f53c4aSTejun Heo BUG_ON(cwq->nr_in_flight[i]); 33831e19ffc6STejun Heo BUG_ON(cwq->nr_active); 33841e19ffc6STejun Heo BUG_ON(!list_empty(&cwq->delayed_works)); 338573f53c4aSTejun Heo } 33861537663fSTejun Heo 3387e22bee78STejun Heo if (wq->flags & WQ_RESCUER) { 3388e22bee78STejun Heo kthread_stop(wq->rescuer->task); 3389f2e005aaSTejun Heo free_mayday_mask(wq->mayday_mask); 33908d9df9f0SXiaotian Feng kfree(wq->rescuer); 3391e22bee78STejun Heo } 3392e22bee78STejun Heo 3393bdbc5dd7STejun Heo free_cwqs(wq); 33943af24433SOleg Nesterov kfree(wq); 33953af24433SOleg Nesterov } 33963af24433SOleg Nesterov EXPORT_SYMBOL_GPL(destroy_workqueue); 33973af24433SOleg Nesterov 3398dcd989cbSTejun Heo /** 33999f4bd4cdSLai Jiangshan * cwq_set_max_active - adjust max_active of a cwq 34009f4bd4cdSLai Jiangshan * @cwq: target cpu_workqueue_struct 34019f4bd4cdSLai Jiangshan * @max_active: new max_active value. 34029f4bd4cdSLai Jiangshan * 34039f4bd4cdSLai Jiangshan * Set @cwq->max_active to @max_active and activate delayed works if 34049f4bd4cdSLai Jiangshan * increased. 34059f4bd4cdSLai Jiangshan * 34069f4bd4cdSLai Jiangshan * CONTEXT: 34079f4bd4cdSLai Jiangshan * spin_lock_irq(gcwq->lock). 34089f4bd4cdSLai Jiangshan */ 34099f4bd4cdSLai Jiangshan static void cwq_set_max_active(struct cpu_workqueue_struct *cwq, int max_active) 34109f4bd4cdSLai Jiangshan { 34119f4bd4cdSLai Jiangshan cwq->max_active = max_active; 34129f4bd4cdSLai Jiangshan 34139f4bd4cdSLai Jiangshan while (!list_empty(&cwq->delayed_works) && 34149f4bd4cdSLai Jiangshan cwq->nr_active < cwq->max_active) 34159f4bd4cdSLai Jiangshan cwq_activate_first_delayed(cwq); 34169f4bd4cdSLai Jiangshan } 34179f4bd4cdSLai Jiangshan 34189f4bd4cdSLai Jiangshan /** 3419dcd989cbSTejun Heo * workqueue_set_max_active - adjust max_active of a workqueue 3420dcd989cbSTejun Heo * @wq: target workqueue 3421dcd989cbSTejun Heo * @max_active: new max_active value. 3422dcd989cbSTejun Heo * 3423dcd989cbSTejun Heo * Set max_active of @wq to @max_active. 3424dcd989cbSTejun Heo * 3425dcd989cbSTejun Heo * CONTEXT: 3426dcd989cbSTejun Heo * Don't call from IRQ context. 3427dcd989cbSTejun Heo */ 3428dcd989cbSTejun Heo void workqueue_set_max_active(struct workqueue_struct *wq, int max_active) 3429dcd989cbSTejun Heo { 3430dcd989cbSTejun Heo unsigned int cpu; 3431dcd989cbSTejun Heo 3432f3421797STejun Heo max_active = wq_clamp_max_active(max_active, wq->flags, wq->name); 3433dcd989cbSTejun Heo 3434dcd989cbSTejun Heo spin_lock(&workqueue_lock); 3435dcd989cbSTejun Heo 3436dcd989cbSTejun Heo wq->saved_max_active = max_active; 3437dcd989cbSTejun Heo 3438f3421797STejun Heo for_each_cwq_cpu(cpu, wq) { 343935b6bb63STejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 344035b6bb63STejun Heo struct worker_pool *pool = cwq->pool; 344135b6bb63STejun Heo struct global_cwq *gcwq = pool->gcwq; 3442dcd989cbSTejun Heo 3443dcd989cbSTejun Heo spin_lock_irq(&gcwq->lock); 3444dcd989cbSTejun Heo 344558a69cb4STejun Heo if (!(wq->flags & WQ_FREEZABLE) || 344635b6bb63STejun Heo !(pool->flags & POOL_FREEZING)) 344735b6bb63STejun Heo cwq_set_max_active(cwq, max_active); 3448dcd989cbSTejun Heo 3449dcd989cbSTejun Heo spin_unlock_irq(&gcwq->lock); 3450dcd989cbSTejun Heo } 3451dcd989cbSTejun Heo 3452dcd989cbSTejun Heo spin_unlock(&workqueue_lock); 3453dcd989cbSTejun Heo } 3454dcd989cbSTejun Heo EXPORT_SYMBOL_GPL(workqueue_set_max_active); 3455dcd989cbSTejun Heo 3456dcd989cbSTejun Heo /** 3457dcd989cbSTejun Heo * workqueue_congested - test whether a workqueue is congested 3458dcd989cbSTejun Heo * @cpu: CPU in question 3459dcd989cbSTejun Heo * @wq: target workqueue 3460dcd989cbSTejun Heo * 3461dcd989cbSTejun Heo * Test whether @wq's cpu workqueue for @cpu is congested. There is 3462dcd989cbSTejun Heo * no synchronization around this function and the test result is 3463dcd989cbSTejun Heo * unreliable and only useful as advisory hints or for debugging. 3464dcd989cbSTejun Heo * 3465dcd989cbSTejun Heo * RETURNS: 3466dcd989cbSTejun Heo * %true if congested, %false otherwise. 3467dcd989cbSTejun Heo */ 3468dcd989cbSTejun Heo bool workqueue_congested(unsigned int cpu, struct workqueue_struct *wq) 3469dcd989cbSTejun Heo { 3470dcd989cbSTejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 3471dcd989cbSTejun Heo 3472dcd989cbSTejun Heo return !list_empty(&cwq->delayed_works); 3473dcd989cbSTejun Heo } 3474dcd989cbSTejun Heo EXPORT_SYMBOL_GPL(workqueue_congested); 3475dcd989cbSTejun Heo 3476dcd989cbSTejun Heo /** 3477dcd989cbSTejun Heo * work_busy - test whether a work is currently pending or running 3478dcd989cbSTejun Heo * @work: the work to be tested 3479dcd989cbSTejun Heo * 3480dcd989cbSTejun Heo * Test whether @work is currently pending or running. There is no 3481dcd989cbSTejun Heo * synchronization around this function and the test result is 3482dcd989cbSTejun Heo * unreliable and only useful as advisory hints or for debugging. 3483dcd989cbSTejun Heo * Especially for reentrant wqs, the pending state might hide the 3484dcd989cbSTejun Heo * running state. 3485dcd989cbSTejun Heo * 3486dcd989cbSTejun Heo * RETURNS: 3487dcd989cbSTejun Heo * OR'd bitmask of WORK_BUSY_* bits. 3488dcd989cbSTejun Heo */ 3489dcd989cbSTejun Heo unsigned int work_busy(struct work_struct *work) 3490dcd989cbSTejun Heo { 3491c9e7cf27STejun Heo struct worker_pool *pool = get_work_pool(work); 3492c9e7cf27STejun Heo struct global_cwq *gcwq; 3493dcd989cbSTejun Heo unsigned long flags; 3494dcd989cbSTejun Heo unsigned int ret = 0; 3495dcd989cbSTejun Heo 3496c9e7cf27STejun Heo if (!pool) 3497999767beSJoonsoo Kim return 0; 3498c9e7cf27STejun Heo gcwq = pool->gcwq; 3499dcd989cbSTejun Heo 3500dcd989cbSTejun Heo spin_lock_irqsave(&gcwq->lock, flags); 3501dcd989cbSTejun Heo 3502dcd989cbSTejun Heo if (work_pending(work)) 3503dcd989cbSTejun Heo ret |= WORK_BUSY_PENDING; 3504c9e7cf27STejun Heo if (find_worker_executing_work(pool, work)) 3505dcd989cbSTejun Heo ret |= WORK_BUSY_RUNNING; 3506dcd989cbSTejun Heo 3507dcd989cbSTejun Heo spin_unlock_irqrestore(&gcwq->lock, flags); 3508dcd989cbSTejun Heo 3509dcd989cbSTejun Heo return ret; 3510dcd989cbSTejun Heo } 3511dcd989cbSTejun Heo EXPORT_SYMBOL_GPL(work_busy); 3512dcd989cbSTejun Heo 3513db7bccf4STejun Heo /* 3514db7bccf4STejun Heo * CPU hotplug. 3515db7bccf4STejun Heo * 3516e22bee78STejun Heo * There are two challenges in supporting CPU hotplug. Firstly, there 3517e22bee78STejun Heo * are a lot of assumptions on strong associations among work, cwq and 3518e22bee78STejun Heo * gcwq which make migrating pending and scheduled works very 3519e22bee78STejun Heo * difficult to implement without impacting hot paths. Secondly, 3520e22bee78STejun Heo * gcwqs serve mix of short, long and very long running works making 3521e22bee78STejun Heo * blocked draining impractical. 3522e22bee78STejun Heo * 352324647570STejun Heo * This is solved by allowing the pools to be disassociated from the CPU 3524628c78e7STejun Heo * running as an unbound one and allowing it to be reattached later if the 3525628c78e7STejun Heo * cpu comes back online. 3526db7bccf4STejun Heo */ 3527db7bccf4STejun Heo 352860373152STejun Heo /* claim manager positions of all pools */ 3529b2eb83d1SLai Jiangshan static void gcwq_claim_assoc_and_lock(struct global_cwq *gcwq) 353060373152STejun Heo { 353160373152STejun Heo struct worker_pool *pool; 353260373152STejun Heo 353360373152STejun Heo for_each_worker_pool(pool, gcwq) 3534b2eb83d1SLai Jiangshan mutex_lock_nested(&pool->assoc_mutex, pool - gcwq->pools); 35358db25e78STejun Heo spin_lock_irq(&gcwq->lock); 353660373152STejun Heo } 353760373152STejun Heo 353860373152STejun Heo /* release manager positions */ 3539b2eb83d1SLai Jiangshan static void gcwq_release_assoc_and_unlock(struct global_cwq *gcwq) 354060373152STejun Heo { 354160373152STejun Heo struct worker_pool *pool; 354260373152STejun Heo 35438db25e78STejun Heo spin_unlock_irq(&gcwq->lock); 354460373152STejun Heo for_each_worker_pool(pool, gcwq) 3545b2eb83d1SLai Jiangshan mutex_unlock(&pool->assoc_mutex); 354660373152STejun Heo } 354760373152STejun Heo 3548628c78e7STejun Heo static void gcwq_unbind_fn(struct work_struct *work) 3549db7bccf4STejun Heo { 3550628c78e7STejun Heo struct global_cwq *gcwq = get_gcwq(smp_processor_id()); 35514ce62e9eSTejun Heo struct worker_pool *pool; 3552db7bccf4STejun Heo struct worker *worker; 3553db7bccf4STejun Heo struct hlist_node *pos; 3554db7bccf4STejun Heo int i; 3555db7bccf4STejun Heo 3556ec22ca5eSTejun Heo BUG_ON(gcwq->pools[0].cpu != smp_processor_id()); 3557db7bccf4STejun Heo 3558b2eb83d1SLai Jiangshan gcwq_claim_assoc_and_lock(gcwq); 3559e22bee78STejun Heo 3560f2d5a0eeSTejun Heo /* 3561f2d5a0eeSTejun Heo * We've claimed all manager positions. Make all workers unbound 3562f2d5a0eeSTejun Heo * and set DISASSOCIATED. Before this, all workers except for the 3563f2d5a0eeSTejun Heo * ones which are still executing works from before the last CPU 3564f2d5a0eeSTejun Heo * down must be on the cpu. After this, they may become diasporas. 3565f2d5a0eeSTejun Heo */ 3566c9e7cf27STejun Heo for_each_worker_pool(pool, gcwq) { 35674ce62e9eSTejun Heo list_for_each_entry(worker, &pool->idle_list, entry) 3568403c821dSTejun Heo worker->flags |= WORKER_UNBOUND; 3569db7bccf4STejun Heo 3570c9e7cf27STejun Heo for_each_busy_worker(worker, i, pos, pool) 3571403c821dSTejun Heo worker->flags |= WORKER_UNBOUND; 3572db7bccf4STejun Heo 357324647570STejun Heo pool->flags |= POOL_DISASSOCIATED; 3574c9e7cf27STejun Heo } 3575f2d5a0eeSTejun Heo 3576b2eb83d1SLai Jiangshan gcwq_release_assoc_and_unlock(gcwq); 3577e22bee78STejun Heo 3578e22bee78STejun Heo /* 3579628c78e7STejun Heo * Call schedule() so that we cross rq->lock and thus can guarantee 3580628c78e7STejun Heo * sched callbacks see the %WORKER_UNBOUND flag. This is necessary 3581628c78e7STejun Heo * as scheduler callbacks may be invoked from other cpus. 3582628c78e7STejun Heo */ 3583628c78e7STejun Heo schedule(); 3584628c78e7STejun Heo 3585628c78e7STejun Heo /* 3586628c78e7STejun Heo * Sched callbacks are disabled now. Zap nr_running. After this, 3587628c78e7STejun Heo * nr_running stays zero and need_more_worker() and keep_working() 3588628c78e7STejun Heo * are always true as long as the worklist is not empty. @gcwq now 3589628c78e7STejun Heo * behaves as unbound (in terms of concurrency management) gcwq 3590628c78e7STejun Heo * which is served by workers tied to the CPU. 3591628c78e7STejun Heo * 3592628c78e7STejun Heo * On return from this function, the current worker would trigger 3593628c78e7STejun Heo * unbound chain execution of pending work items if other workers 3594628c78e7STejun Heo * didn't already. 3595e22bee78STejun Heo */ 35964ce62e9eSTejun Heo for_each_worker_pool(pool, gcwq) 35974ce62e9eSTejun Heo atomic_set(get_pool_nr_running(pool), 0); 3598db7bccf4STejun Heo } 3599db7bccf4STejun Heo 36008db25e78STejun Heo /* 36018db25e78STejun Heo * Workqueues should be brought up before normal priority CPU notifiers. 36028db25e78STejun Heo * This will be registered high priority CPU notifier. 36038db25e78STejun Heo */ 36049fdf9b73SLai Jiangshan static int __cpuinit workqueue_cpu_up_callback(struct notifier_block *nfb, 36051da177e4SLinus Torvalds unsigned long action, 36061da177e4SLinus Torvalds void *hcpu) 36071da177e4SLinus Torvalds { 36083af24433SOleg Nesterov unsigned int cpu = (unsigned long)hcpu; 3609db7bccf4STejun Heo struct global_cwq *gcwq = get_gcwq(cpu); 36104ce62e9eSTejun Heo struct worker_pool *pool; 36111da177e4SLinus Torvalds 36128db25e78STejun Heo switch (action & ~CPU_TASKS_FROZEN) { 36133af24433SOleg Nesterov case CPU_UP_PREPARE: 36144ce62e9eSTejun Heo for_each_worker_pool(pool, gcwq) { 36153ce63377STejun Heo struct worker *worker; 36163ce63377STejun Heo 36173ce63377STejun Heo if (pool->nr_workers) 36183ce63377STejun Heo continue; 36193ce63377STejun Heo 36203ce63377STejun Heo worker = create_worker(pool); 36213ce63377STejun Heo if (!worker) 36223ce63377STejun Heo return NOTIFY_BAD; 36233ce63377STejun Heo 36243ce63377STejun Heo spin_lock_irq(&gcwq->lock); 36253ce63377STejun Heo start_worker(worker); 36263ce63377STejun Heo spin_unlock_irq(&gcwq->lock); 36273af24433SOleg Nesterov } 36281da177e4SLinus Torvalds break; 36291da177e4SLinus Torvalds 363065758202STejun Heo case CPU_DOWN_FAILED: 363165758202STejun Heo case CPU_ONLINE: 3632b2eb83d1SLai Jiangshan gcwq_claim_assoc_and_lock(gcwq); 363324647570STejun Heo for_each_worker_pool(pool, gcwq) 363424647570STejun Heo pool->flags &= ~POOL_DISASSOCIATED; 36358db25e78STejun Heo rebind_workers(gcwq); 3636b2eb83d1SLai Jiangshan gcwq_release_assoc_and_unlock(gcwq); 36378db25e78STejun Heo break; 363865758202STejun Heo } 363965758202STejun Heo return NOTIFY_OK; 364065758202STejun Heo } 364165758202STejun Heo 364265758202STejun Heo /* 364365758202STejun Heo * Workqueues should be brought down after normal priority CPU notifiers. 364465758202STejun Heo * This will be registered as low priority CPU notifier. 364565758202STejun Heo */ 36469fdf9b73SLai Jiangshan static int __cpuinit workqueue_cpu_down_callback(struct notifier_block *nfb, 364765758202STejun Heo unsigned long action, 364865758202STejun Heo void *hcpu) 364965758202STejun Heo { 36508db25e78STejun Heo unsigned int cpu = (unsigned long)hcpu; 36518db25e78STejun Heo struct work_struct unbind_work; 36528db25e78STejun Heo 365365758202STejun Heo switch (action & ~CPU_TASKS_FROZEN) { 365465758202STejun Heo case CPU_DOWN_PREPARE: 36558db25e78STejun Heo /* unbinding should happen on the local CPU */ 36568db25e78STejun Heo INIT_WORK_ONSTACK(&unbind_work, gcwq_unbind_fn); 36577635d2fdSJoonsoo Kim queue_work_on(cpu, system_highpri_wq, &unbind_work); 36588db25e78STejun Heo flush_work(&unbind_work); 36598db25e78STejun Heo break; 366065758202STejun Heo } 366165758202STejun Heo return NOTIFY_OK; 366265758202STejun Heo } 366365758202STejun Heo 36642d3854a3SRusty Russell #ifdef CONFIG_SMP 36658ccad40dSRusty Russell 36662d3854a3SRusty Russell struct work_for_cpu { 3667ed48ece2STejun Heo struct work_struct work; 36682d3854a3SRusty Russell long (*fn)(void *); 36692d3854a3SRusty Russell void *arg; 36702d3854a3SRusty Russell long ret; 36712d3854a3SRusty Russell }; 36722d3854a3SRusty Russell 3673ed48ece2STejun Heo static void work_for_cpu_fn(struct work_struct *work) 36742d3854a3SRusty Russell { 3675ed48ece2STejun Heo struct work_for_cpu *wfc = container_of(work, struct work_for_cpu, work); 3676ed48ece2STejun Heo 36772d3854a3SRusty Russell wfc->ret = wfc->fn(wfc->arg); 36782d3854a3SRusty Russell } 36792d3854a3SRusty Russell 36802d3854a3SRusty Russell /** 36812d3854a3SRusty Russell * work_on_cpu - run a function in user context on a particular cpu 36822d3854a3SRusty Russell * @cpu: the cpu to run on 36832d3854a3SRusty Russell * @fn: the function to run 36842d3854a3SRusty Russell * @arg: the function arg 36852d3854a3SRusty Russell * 368631ad9081SRusty Russell * This will return the value @fn returns. 368731ad9081SRusty Russell * It is up to the caller to ensure that the cpu doesn't go offline. 36886b44003eSAndrew Morton * The caller must not hold any locks which would prevent @fn from completing. 36892d3854a3SRusty Russell */ 36902d3854a3SRusty Russell long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg) 36912d3854a3SRusty Russell { 3692ed48ece2STejun Heo struct work_for_cpu wfc = { .fn = fn, .arg = arg }; 36932d3854a3SRusty Russell 3694ed48ece2STejun Heo INIT_WORK_ONSTACK(&wfc.work, work_for_cpu_fn); 3695ed48ece2STejun Heo schedule_work_on(cpu, &wfc.work); 3696ed48ece2STejun Heo flush_work(&wfc.work); 36972d3854a3SRusty Russell return wfc.ret; 36982d3854a3SRusty Russell } 36992d3854a3SRusty Russell EXPORT_SYMBOL_GPL(work_on_cpu); 37002d3854a3SRusty Russell #endif /* CONFIG_SMP */ 37012d3854a3SRusty Russell 3702a0a1a5fdSTejun Heo #ifdef CONFIG_FREEZER 3703e7577c50SRusty Russell 3704a0a1a5fdSTejun Heo /** 3705a0a1a5fdSTejun Heo * freeze_workqueues_begin - begin freezing workqueues 3706a0a1a5fdSTejun Heo * 370758a69cb4STejun Heo * Start freezing workqueues. After this function returns, all freezable 370858a69cb4STejun Heo * workqueues will queue new works to their frozen_works list instead of 370958a69cb4STejun Heo * gcwq->worklist. 3710a0a1a5fdSTejun Heo * 3711a0a1a5fdSTejun Heo * CONTEXT: 37128b03ae3cSTejun Heo * Grabs and releases workqueue_lock and gcwq->lock's. 3713a0a1a5fdSTejun Heo */ 3714a0a1a5fdSTejun Heo void freeze_workqueues_begin(void) 3715a0a1a5fdSTejun Heo { 3716a0a1a5fdSTejun Heo unsigned int cpu; 3717a0a1a5fdSTejun Heo 3718a0a1a5fdSTejun Heo spin_lock(&workqueue_lock); 3719a0a1a5fdSTejun Heo 3720a0a1a5fdSTejun Heo BUG_ON(workqueue_freezing); 3721a0a1a5fdSTejun Heo workqueue_freezing = true; 3722a0a1a5fdSTejun Heo 3723f3421797STejun Heo for_each_gcwq_cpu(cpu) { 37248b03ae3cSTejun Heo struct global_cwq *gcwq = get_gcwq(cpu); 372535b6bb63STejun Heo struct worker_pool *pool; 3726bdbc5dd7STejun Heo struct workqueue_struct *wq; 37278b03ae3cSTejun Heo 37288b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 37298b03ae3cSTejun Heo 373035b6bb63STejun Heo for_each_worker_pool(pool, gcwq) { 373135b6bb63STejun Heo WARN_ON_ONCE(pool->flags & POOL_FREEZING); 373235b6bb63STejun Heo pool->flags |= POOL_FREEZING; 373335b6bb63STejun Heo } 3734db7bccf4STejun Heo 3735a0a1a5fdSTejun Heo list_for_each_entry(wq, &workqueues, list) { 3736a0a1a5fdSTejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 3737a0a1a5fdSTejun Heo 373858a69cb4STejun Heo if (cwq && wq->flags & WQ_FREEZABLE) 3739a0a1a5fdSTejun Heo cwq->max_active = 0; 37401da177e4SLinus Torvalds } 37418b03ae3cSTejun Heo 37428b03ae3cSTejun Heo spin_unlock_irq(&gcwq->lock); 3743a0a1a5fdSTejun Heo } 3744a0a1a5fdSTejun Heo 3745a0a1a5fdSTejun Heo spin_unlock(&workqueue_lock); 3746a0a1a5fdSTejun Heo } 3747a0a1a5fdSTejun Heo 3748a0a1a5fdSTejun Heo /** 374958a69cb4STejun Heo * freeze_workqueues_busy - are freezable workqueues still busy? 3750a0a1a5fdSTejun Heo * 3751a0a1a5fdSTejun Heo * Check whether freezing is complete. This function must be called 3752a0a1a5fdSTejun Heo * between freeze_workqueues_begin() and thaw_workqueues(). 3753a0a1a5fdSTejun Heo * 3754a0a1a5fdSTejun Heo * CONTEXT: 3755a0a1a5fdSTejun Heo * Grabs and releases workqueue_lock. 3756a0a1a5fdSTejun Heo * 3757a0a1a5fdSTejun Heo * RETURNS: 375858a69cb4STejun Heo * %true if some freezable workqueues are still busy. %false if freezing 375958a69cb4STejun Heo * is complete. 3760a0a1a5fdSTejun Heo */ 3761a0a1a5fdSTejun Heo bool freeze_workqueues_busy(void) 3762a0a1a5fdSTejun Heo { 3763a0a1a5fdSTejun Heo unsigned int cpu; 3764a0a1a5fdSTejun Heo bool busy = false; 3765a0a1a5fdSTejun Heo 3766a0a1a5fdSTejun Heo spin_lock(&workqueue_lock); 3767a0a1a5fdSTejun Heo 3768a0a1a5fdSTejun Heo BUG_ON(!workqueue_freezing); 3769a0a1a5fdSTejun Heo 3770f3421797STejun Heo for_each_gcwq_cpu(cpu) { 3771bdbc5dd7STejun Heo struct workqueue_struct *wq; 3772a0a1a5fdSTejun Heo /* 3773a0a1a5fdSTejun Heo * nr_active is monotonically decreasing. It's safe 3774a0a1a5fdSTejun Heo * to peek without lock. 3775a0a1a5fdSTejun Heo */ 3776a0a1a5fdSTejun Heo list_for_each_entry(wq, &workqueues, list) { 3777a0a1a5fdSTejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 3778a0a1a5fdSTejun Heo 377958a69cb4STejun Heo if (!cwq || !(wq->flags & WQ_FREEZABLE)) 3780a0a1a5fdSTejun Heo continue; 3781a0a1a5fdSTejun Heo 3782a0a1a5fdSTejun Heo BUG_ON(cwq->nr_active < 0); 3783a0a1a5fdSTejun Heo if (cwq->nr_active) { 3784a0a1a5fdSTejun Heo busy = true; 3785a0a1a5fdSTejun Heo goto out_unlock; 3786a0a1a5fdSTejun Heo } 3787a0a1a5fdSTejun Heo } 3788a0a1a5fdSTejun Heo } 3789a0a1a5fdSTejun Heo out_unlock: 3790a0a1a5fdSTejun Heo spin_unlock(&workqueue_lock); 3791a0a1a5fdSTejun Heo return busy; 3792a0a1a5fdSTejun Heo } 3793a0a1a5fdSTejun Heo 3794a0a1a5fdSTejun Heo /** 3795a0a1a5fdSTejun Heo * thaw_workqueues - thaw workqueues 3796a0a1a5fdSTejun Heo * 3797a0a1a5fdSTejun Heo * Thaw workqueues. Normal queueing is restored and all collected 37987e11629dSTejun Heo * frozen works are transferred to their respective gcwq worklists. 3799a0a1a5fdSTejun Heo * 3800a0a1a5fdSTejun Heo * CONTEXT: 38018b03ae3cSTejun Heo * Grabs and releases workqueue_lock and gcwq->lock's. 3802a0a1a5fdSTejun Heo */ 3803a0a1a5fdSTejun Heo void thaw_workqueues(void) 3804a0a1a5fdSTejun Heo { 3805a0a1a5fdSTejun Heo unsigned int cpu; 3806a0a1a5fdSTejun Heo 3807a0a1a5fdSTejun Heo spin_lock(&workqueue_lock); 3808a0a1a5fdSTejun Heo 3809a0a1a5fdSTejun Heo if (!workqueue_freezing) 3810a0a1a5fdSTejun Heo goto out_unlock; 3811a0a1a5fdSTejun Heo 3812f3421797STejun Heo for_each_gcwq_cpu(cpu) { 38138b03ae3cSTejun Heo struct global_cwq *gcwq = get_gcwq(cpu); 38144ce62e9eSTejun Heo struct worker_pool *pool; 3815bdbc5dd7STejun Heo struct workqueue_struct *wq; 38168b03ae3cSTejun Heo 38178b03ae3cSTejun Heo spin_lock_irq(&gcwq->lock); 38188b03ae3cSTejun Heo 381935b6bb63STejun Heo for_each_worker_pool(pool, gcwq) { 382035b6bb63STejun Heo WARN_ON_ONCE(!(pool->flags & POOL_FREEZING)); 382135b6bb63STejun Heo pool->flags &= ~POOL_FREEZING; 382235b6bb63STejun Heo } 3823db7bccf4STejun Heo 3824a0a1a5fdSTejun Heo list_for_each_entry(wq, &workqueues, list) { 3825a0a1a5fdSTejun Heo struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); 3826a0a1a5fdSTejun Heo 382758a69cb4STejun Heo if (!cwq || !(wq->flags & WQ_FREEZABLE)) 3828a0a1a5fdSTejun Heo continue; 3829a0a1a5fdSTejun Heo 3830a0a1a5fdSTejun Heo /* restore max_active and repopulate worklist */ 38319f4bd4cdSLai Jiangshan cwq_set_max_active(cwq, wq->saved_max_active); 3832a0a1a5fdSTejun Heo } 38338b03ae3cSTejun Heo 38344ce62e9eSTejun Heo for_each_worker_pool(pool, gcwq) 38354ce62e9eSTejun Heo wake_up_worker(pool); 3836e22bee78STejun Heo 38378b03ae3cSTejun Heo spin_unlock_irq(&gcwq->lock); 3838a0a1a5fdSTejun Heo } 3839a0a1a5fdSTejun Heo 3840a0a1a5fdSTejun Heo workqueue_freezing = false; 3841a0a1a5fdSTejun Heo out_unlock: 3842a0a1a5fdSTejun Heo spin_unlock(&workqueue_lock); 3843a0a1a5fdSTejun Heo } 3844a0a1a5fdSTejun Heo #endif /* CONFIG_FREEZER */ 3845a0a1a5fdSTejun Heo 38466ee0578bSSuresh Siddha static int __init init_workqueues(void) 38471da177e4SLinus Torvalds { 3848c34056a3STejun Heo unsigned int cpu; 3849c34056a3STejun Heo 38507c3eed5cSTejun Heo /* make sure we have enough bits for OFFQ pool ID */ 38517c3eed5cSTejun Heo BUILD_BUG_ON((1LU << (BITS_PER_LONG - WORK_OFFQ_POOL_SHIFT)) < 38527c3eed5cSTejun Heo WORK_CPU_LAST * NR_STD_WORKER_POOLS); 3853b5490077STejun Heo 385465758202STejun Heo cpu_notifier(workqueue_cpu_up_callback, CPU_PRI_WORKQUEUE_UP); 3855a5b4e57dSLai Jiangshan hotcpu_notifier(workqueue_cpu_down_callback, CPU_PRI_WORKQUEUE_DOWN); 38568b03ae3cSTejun Heo 38578b03ae3cSTejun Heo /* initialize gcwqs */ 3858f3421797STejun Heo for_each_gcwq_cpu(cpu) { 38598b03ae3cSTejun Heo struct global_cwq *gcwq = get_gcwq(cpu); 38604ce62e9eSTejun Heo struct worker_pool *pool; 38618b03ae3cSTejun Heo 38628b03ae3cSTejun Heo spin_lock_init(&gcwq->lock); 38638b03ae3cSTejun Heo 38644ce62e9eSTejun Heo for_each_worker_pool(pool, gcwq) { 38654ce62e9eSTejun Heo pool->gcwq = gcwq; 3866ec22ca5eSTejun Heo pool->cpu = cpu; 386724647570STejun Heo pool->flags |= POOL_DISASSOCIATED; 38684ce62e9eSTejun Heo INIT_LIST_HEAD(&pool->worklist); 38694ce62e9eSTejun Heo INIT_LIST_HEAD(&pool->idle_list); 3870c9e7cf27STejun Heo hash_init(pool->busy_hash); 3871e22bee78STejun Heo 38724ce62e9eSTejun Heo init_timer_deferrable(&pool->idle_timer); 38734ce62e9eSTejun Heo pool->idle_timer.function = idle_worker_timeout; 38744ce62e9eSTejun Heo pool->idle_timer.data = (unsigned long)pool; 3875e22bee78STejun Heo 38764ce62e9eSTejun Heo setup_timer(&pool->mayday_timer, gcwq_mayday_timeout, 38774ce62e9eSTejun Heo (unsigned long)pool); 38784ce62e9eSTejun Heo 3879b2eb83d1SLai Jiangshan mutex_init(&pool->assoc_mutex); 38804ce62e9eSTejun Heo ida_init(&pool->worker_ida); 38819daf9e67STejun Heo 38829daf9e67STejun Heo /* alloc pool ID */ 38839daf9e67STejun Heo BUG_ON(worker_pool_assign_id(pool)); 38844ce62e9eSTejun Heo } 38858b03ae3cSTejun Heo } 38868b03ae3cSTejun Heo 3887e22bee78STejun Heo /* create the initial worker */ 3888f3421797STejun Heo for_each_online_gcwq_cpu(cpu) { 3889e22bee78STejun Heo struct global_cwq *gcwq = get_gcwq(cpu); 38904ce62e9eSTejun Heo struct worker_pool *pool; 3891e22bee78STejun Heo 38924ce62e9eSTejun Heo for_each_worker_pool(pool, gcwq) { 38934ce62e9eSTejun Heo struct worker *worker; 38944ce62e9eSTejun Heo 389524647570STejun Heo if (cpu != WORK_CPU_UNBOUND) 389624647570STejun Heo pool->flags &= ~POOL_DISASSOCIATED; 389724647570STejun Heo 3898bc2ae0f5STejun Heo worker = create_worker(pool); 3899e22bee78STejun Heo BUG_ON(!worker); 3900e22bee78STejun Heo spin_lock_irq(&gcwq->lock); 3901e22bee78STejun Heo start_worker(worker); 3902e22bee78STejun Heo spin_unlock_irq(&gcwq->lock); 3903e22bee78STejun Heo } 39044ce62e9eSTejun Heo } 3905e22bee78STejun Heo 3906d320c038STejun Heo system_wq = alloc_workqueue("events", 0, 0); 39071aabe902SJoonsoo Kim system_highpri_wq = alloc_workqueue("events_highpri", WQ_HIGHPRI, 0); 3908d320c038STejun Heo system_long_wq = alloc_workqueue("events_long", 0, 0); 3909f3421797STejun Heo system_unbound_wq = alloc_workqueue("events_unbound", WQ_UNBOUND, 3910f3421797STejun Heo WQ_UNBOUND_MAX_ACTIVE); 391124d51addSTejun Heo system_freezable_wq = alloc_workqueue("events_freezable", 391224d51addSTejun Heo WQ_FREEZABLE, 0); 39131aabe902SJoonsoo Kim BUG_ON(!system_wq || !system_highpri_wq || !system_long_wq || 3914ae930e0fSTejun Heo !system_unbound_wq || !system_freezable_wq); 39156ee0578bSSuresh Siddha return 0; 39161da177e4SLinus Torvalds } 39176ee0578bSSuresh Siddha early_initcall(init_workqueues); 3918