diff options
| -rw-r--r-- | kernel/workqueue.c | 316 |
1 files changed, 154 insertions, 162 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 366132bd226f..c93651208760 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -108,12 +108,12 @@ enum { * P: Preemption protected. Disabling preemption is enough and should * only be modified and accessed from the local cpu. * - * L: gcwq->lock protected. Access with gcwq->lock held. + * L: pool->lock protected. Access with pool->lock held. * - * X: During normal operation, modification requires gcwq->lock and - * should be done only from local cpu. Either disabling preemption - * on local cpu or grabbing gcwq->lock is enough for read access. - * If POOL_DISASSOCIATED is set, it's identical to L. + * X: During normal operation, modification requires pool->lock and should + * be done only from local cpu. Either disabling preemption on local + * cpu or grabbing pool->lock is enough for read access. If + * POOL_DISASSOCIATED is set, it's identical to L. * * F: wq->flush_mutex protected. * @@ -124,6 +124,7 @@ enum { struct worker_pool { struct global_cwq *gcwq; /* I: the owning gcwq */ + spinlock_t lock; /* the pool lock */ unsigned int cpu; /* I: the associated cpu */ int id; /* I: pool ID */ unsigned int flags; /* X: flags */ @@ -152,8 +153,6 @@ struct worker_pool { * target workqueues. */ struct global_cwq { - spinlock_t lock; /* the gcwq lock */ - struct worker_pool pools[NR_STD_WORKER_POOLS]; /* normal and highpri pools */ } ____cacheline_aligned_in_smp; @@ -487,6 +486,13 @@ static struct worker_pool *worker_pool_by_id(int pool_id) return idr_find(&worker_pool_idr, pool_id); } +static struct worker_pool *get_std_worker_pool(int cpu, bool highpri) +{ + struct global_cwq *gcwq = get_gcwq(cpu); + + return &gcwq->pools[highpri]; +} + static atomic_t *get_pool_nr_running(struct worker_pool *pool) { int cpu = pool->cpu; @@ -628,13 +634,6 @@ static int get_work_pool_id(struct work_struct *work) return pool ? pool->id : WORK_OFFQ_POOL_NONE; } -static struct global_cwq *get_work_gcwq(struct work_struct *work) -{ - struct worker_pool *pool = get_work_pool(work); - - return pool ? pool->gcwq : NULL; -} - static void mark_work_canceling(struct work_struct *work) { unsigned long pool_id = get_work_pool_id(work); @@ -653,7 +652,7 @@ static bool work_is_canceling(struct work_struct *work) /* * Policy functions. These define the policies on how the global worker * pools are managed. Unless noted otherwise, these functions assume that - * they're being called with gcwq->lock held. + * they're being called with pool->lock held. */ static bool __need_more_worker(struct worker_pool *pool) @@ -738,7 +737,7 @@ static struct worker *first_worker(struct worker_pool *pool) * Wake up the first idle worker of @pool. * * CONTEXT: - * spin_lock_irq(gcwq->lock). + * spin_lock_irq(pool->lock). */ static void wake_up_worker(struct worker_pool *pool) { @@ -813,7 +812,7 @@ struct task_struct *wq_worker_sleeping(struct task_struct *task, * NOT_RUNNING is clear. This means that we're bound to and * running on the local cpu w/ rq lock held and preemption * disabled, which in turn means that none else could be - * manipulating idle_list, so dereferencing idle_list without gcwq + * manipulating idle_list, so dereferencing idle_list without pool * lock is safe. */ if (atomic_dec_and_test(nr_running) && !list_empty(&pool->worklist)) @@ -832,7 +831,7 @@ struct task_struct *wq_worker_sleeping(struct task_struct *task, * woken up. * * CONTEXT: - * spin_lock_irq(gcwq->lock) + * spin_lock_irq(pool->lock) */ static inline void worker_set_flags(struct worker *worker, unsigned int flags, bool wakeup) @@ -869,7 +868,7 @@ static inline void worker_set_flags(struct worker *worker, unsigned int flags, * Clear @flags in @worker->flags and adjust nr_running accordingly. * * CONTEXT: - * spin_lock_irq(gcwq->lock) + * spin_lock_irq(pool->lock) */ static inline void worker_clr_flags(struct worker *worker, unsigned int flags) { @@ -918,7 +917,7 @@ static inline void worker_clr_flags(struct worker *worker, unsigned int flags) * function. * * CONTEXT: - * spin_lock_irq(gcwq->lock). + * spin_lock_irq(pool->lock). * * RETURNS: * Pointer to worker which is executing @work if found, NULL @@ -954,7 +953,7 @@ static struct worker *find_worker_executing_work(struct worker_pool *pool, * nested inside outer list_for_each_entry_safe(). * * CONTEXT: - * spin_lock_irq(gcwq->lock). + * spin_lock_irq(pool->lock). */ static void move_linked_works(struct work_struct *work, struct list_head *head, struct work_struct **nextp) @@ -1007,7 +1006,7 @@ static void cwq_activate_first_delayed(struct cpu_workqueue_struct *cwq) * decrement nr_in_flight of its cwq and handle workqueue flushing. * * CONTEXT: - * spin_lock_irq(gcwq->lock). + * spin_lock_irq(pool->lock). */ static void cwq_dec_nr_in_flight(struct cpu_workqueue_struct *cwq, int color) { @@ -1071,7 +1070,7 @@ static void cwq_dec_nr_in_flight(struct cpu_workqueue_struct *cwq, int color) static int try_to_grab_pending(struct work_struct *work, bool is_dwork, unsigned long *flags) { - struct global_cwq *gcwq; + struct worker_pool *pool; local_irq_save(*flags); @@ -1096,19 +1095,19 @@ static int try_to_grab_pending(struct work_struct *work, bool is_dwork, * The queueing is in progress, or it is already queued. Try to * steal it from ->worklist without clearing WORK_STRUCT_PENDING. */ - gcwq = get_work_gcwq(work); - if (!gcwq) + pool = get_work_pool(work); + if (!pool) goto fail; - spin_lock(&gcwq->lock); + spin_lock(&pool->lock); if (!list_empty(&work->entry)) { /* - * This work is queued, but perhaps we locked the wrong gcwq. - * In that case we must see the new value after rmb(), see - * insert_work()->wmb(). + * This work is queued, but perhaps we locked the wrong + * pool. In that case we must see the new value after + * rmb(), see insert_work()->wmb(). */ smp_rmb(); - if (gcwq == get_work_gcwq(work)) { + if (pool == get_work_pool(work)) { debug_work_deactivate(work); /* @@ -1126,11 +1125,11 @@ static int try_to_grab_pending(struct work_struct *work, bool is_dwork, cwq_dec_nr_in_flight(get_work_cwq(work), get_work_color(work)); - spin_unlock(&gcwq->lock); + spin_unlock(&pool->lock); return 1; } } - spin_unlock(&gcwq->lock); + spin_unlock(&pool->lock); fail: local_irq_restore(*flags); if (work_is_canceling(work)) @@ -1150,7 +1149,7 @@ fail: * @extra_flags is or'd to work_struct flags. * * CONTEXT: - * spin_lock_irq(gcwq->lock). + * spin_lock_irq(pool->lock). */ static void insert_work(struct cpu_workqueue_struct *cwq, struct work_struct *work, struct list_head *head, @@ -1193,23 +1192,22 @@ static bool is_chained_work(struct workqueue_struct *wq) for_each_gcwq_cpu(cpu) { struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); struct worker_pool *pool = cwq->pool; - struct global_cwq *gcwq = pool->gcwq; struct worker *worker; struct hlist_node *pos; int i; - spin_lock_irqsave(&gcwq->lock, flags); + spin_lock_irqsave(&pool->lock, flags); for_each_busy_worker(worker, i, pos, pool) { if (worker->task != current) continue; - spin_unlock_irqrestore(&gcwq->lock, flags); + spin_unlock_irqrestore(&pool->lock, flags); /* * I'm @worker, no locking necessary. See if @work * is headed to the same workqueue. */ return worker->current_cwq->wq == wq; } - spin_unlock_irqrestore(&gcwq->lock, flags); + spin_unlock_irqrestore(&pool->lock, flags); } return false; } @@ -1217,7 +1215,8 @@ static bool is_chained_work(struct workqueue_struct *wq) static void __queue_work(unsigned int cpu, struct workqueue_struct *wq, struct work_struct *work) { - struct global_cwq *gcwq; + bool highpri = wq->flags & WQ_HIGHPRI; + struct worker_pool *pool; struct cpu_workqueue_struct *cwq; struct list_head *worklist; unsigned int work_flags; @@ -1238,7 +1237,7 @@ static void __queue_work(unsigned int cpu, struct workqueue_struct *wq, WARN_ON_ONCE(!is_chained_work(wq))) return; - /* determine gcwq to use */ + /* determine pool to use */ if (!(wq->flags & WQ_UNBOUND)) { struct worker_pool *last_pool; @@ -1251,38 +1250,37 @@ static void __queue_work(unsigned int cpu, struct workqueue_struct *wq, * work needs to be queued on that cpu to guarantee * non-reentrancy. */ - gcwq = get_gcwq(cpu); + pool = get_std_worker_pool(cpu, highpri); last_pool = get_work_pool(work); - if (last_pool && last_pool->gcwq != gcwq) { - struct global_cwq *last_gcwq = last_pool->gcwq; + if (last_pool && last_pool != pool) { struct worker *worker; - spin_lock(&last_gcwq->lock); + spin_lock(&last_pool->lock); worker = find_worker_executing_work(last_pool, work); if (worker && worker->current_cwq->wq == wq) - gcwq = last_gcwq; + pool = last_pool; else { /* meh... not running there, queue here */ - spin_unlock(&last_gcwq->lock); - spin_lock(&gcwq->lock); + spin_unlock(&last_pool->lock); + spin_lock(&pool->lock); } } else { - spin_lock(&gcwq->lock); + spin_lock(&pool->lock); } } else { - gcwq = get_gcwq(WORK_CPU_UNBOUND); - spin_lock(&gcwq->lock); + pool = get_std_worker_pool(WORK_CPU_UNBOUND, highpri); + spin_lock(&pool->lock); } - /* gcwq determined, get cwq and queue */ - cwq = get_cwq(gcwq->pools[0].cpu, wq); + /* pool determined, get cwq and queue */ + cwq = get_cwq(pool->cpu, wq); trace_workqueue_queue_work(req_cpu, cwq, work); if (WARN_ON(!list_empty(&work->entry))) { - spin_unlock(&gcwq->lock); + spin_unlock(&pool->lock); return; } @@ -1300,7 +1298,7 @@ static void __queue_work(unsigned int cpu, struct workqueue_struct *wq, insert_work(cwq, work, worklist, work_flags); - spin_unlock(&gcwq->lock); + spin_unlock(&pool->lock); } /** @@ -1523,7 +1521,7 @@ EXPORT_SYMBOL_GPL(mod_delayed_work); * necessary. * * LOCKING: - * spin_lock_irq(gcwq->lock). + * spin_lock_irq(pool->lock). */ static void worker_enter_idle(struct worker *worker) { @@ -1546,7 +1544,7 @@ static void worker_enter_idle(struct worker *worker) /* * Sanity check nr_running. Because gcwq_unbind_fn() releases - * gcwq->lock between setting %WORKER_UNBOUND and zapping + * pool->lock between setting %WORKER_UNBOUND and zapping * nr_running, the warning may trigger spuriously. Check iff * unbind is not in progress. */ @@ -1562,7 +1560,7 @@ static void worker_enter_idle(struct worker *worker) * @worker is leaving idle state. Update stats. * * LOCKING: - * spin_lock_irq(gcwq->lock). + * spin_lock_irq(pool->lock). */ static void worker_leave_idle(struct worker *worker) { @@ -1597,7 +1595,7 @@ static void worker_leave_idle(struct worker *worker) * guarantee the scheduling requirement described in the first paragraph. * * CONTEXT: - * Might sleep. Called without any lock but returns with gcwq->lock + * Might sleep. Called without any lock but returns with pool->lock * held. * * RETURNS: @@ -1605,10 +1603,9 @@ static void worker_leave_idle(struct worker *worker) * bound), %false if offline. */ static bool worker_maybe_bind_and_lock(struct worker *worker) -__acquires(&gcwq->lock) +__acquires(&pool->lock) { struct worker_pool *pool = worker->pool; - struct global_cwq *gcwq = pool->gcwq; struct task_struct *task = worker->task; while (true) { @@ -1621,14 +1618,14 @@ __acquires(&gcwq->lock) if (!(pool->flags & POOL_DISASSOCIATED)) set_cpus_allowed_ptr(task, get_cpu_mask(pool->cpu)); - spin_lock_irq(&gcwq->lock); + spin_lock_irq(&pool->lock); if (pool->flags & POOL_DISASSOCIATED) return false; if (task_cpu(task) == pool->cpu && cpumask_equal(¤t->cpus_allowed, get_cpu_mask(pool->cpu))) return true; - spin_unlock_irq(&gcwq->lock); + spin_unlock_irq(&pool->lock); /* * We've raced with CPU hot[un]plug. Give it a breather @@ -1647,15 +1644,13 @@ __acquires(&gcwq->lock) */ static void idle_worker_rebind(struct worker *worker) { - struct global_cwq *gcwq = worker->pool->gcwq; - /* CPU may go down again inbetween, clear UNBOUND only on success */ if (worker_maybe_bind_and_lock(worker)) worker_clr_flags(worker, WORKER_UNBOUND); /* rebind complete, become available again */ list_add(&worker->entry, &worker->pool->idle_list); - spin_unlock_irq(&gcwq->lock); + spin_unlock_irq(&worker->pool->lock); } /* @@ -1667,12 +1662,11 @@ static void idle_worker_rebind(struct worker *worker) static void busy_worker_rebind_fn(struct work_struct *work) { struct worker *worker = container_of(work, struct worker, rebind_work); - struct global_cwq *gcwq = worker->pool->gcwq; if (worker_maybe_bind_and_lock(worker)) worker_clr_flags(worker, WORKER_UNBOUND); - spin_unlock_irq(&gcwq->lock); + spin_unlock_irq(&worker->pool->lock); } /** @@ -1704,10 +1698,10 @@ static void rebind_workers(struct global_cwq *gcwq) struct hlist_node *pos; int i; - lockdep_assert_held(&gcwq->lock); - - for_each_worker_pool(pool, gcwq) + for_each_worker_pool(pool, gcwq) { lockdep_assert_held(&pool->assoc_mutex); + lockdep_assert_held(&pool->lock); + } /* dequeue and kick idle ones */ for_each_worker_pool(pool, gcwq) { @@ -1785,19 +1779,18 @@ static struct worker *alloc_worker(void) */ static struct worker *create_worker(struct worker_pool *pool) { - struct global_cwq *gcwq = pool->gcwq; const char *pri = std_worker_pool_pri(pool) ? "H" : ""; struct worker *worker = NULL; int id = -1; - spin_lock_irq(&gcwq->lock); + spin_lock_irq(&pool->lock); while (ida_get_new(&pool->worker_ida, &id)) { - spin_unlock_irq(&gcwq->lock); + spin_unlock_irq(&pool->lock); if (!ida_pre_get(&pool->worker_ida, GFP_KERNEL)) goto fail; - spin_lock_irq(&gcwq->lock); + spin_lock_irq(&pool->lock); } - spin_unlock_irq(&gcwq->lock); + spin_unlock_irq(&pool->lock); worker = alloc_worker(); if (!worker) @@ -1838,9 +1831,9 @@ static struct worker *create_worker(struct worker_pool *pool) return worker; fail: if (id >= 0) { - spin_lock_irq(&gcwq->lock); + spin_lock_irq(&pool->lock); ida_remove(&pool->worker_ida, id); - spin_unlock_irq(&gcwq->lock); + spin_unlock_irq(&pool->lock); } kfree(worker); return NULL; @@ -1853,7 +1846,7 @@ fail: * Make the gcwq aware of @worker and start it. * * CONTEXT: - * spin_lock_irq(gcwq->lock). + * spin_lock_irq(pool->lock). */ static void start_worker(struct worker *worker) { @@ -1870,12 +1863,11 @@ static void start_worker(struct worker *worker) * Destroy @worker and adjust @gcwq stats accordingly. * * CONTEXT: - * spin_lock_irq(gcwq->lock) which is released and regrabbed. + * spin_lock_irq(pool->lock) which is released and regrabbed. */ static void destroy_worker(struct worker *worker) { struct worker_pool *pool = worker->pool; - struct global_cwq *gcwq = pool->gcwq; int id = worker->id; /* sanity check frenzy */ @@ -1890,21 +1882,20 @@ static void destroy_worker(struct worker *worker) list_del_init(&worker->entry); worker->flags |= WORKER_DIE; - spin_unlock_irq(&gcwq->lock); + spin_unlock_irq(&pool->lock); kthread_stop(worker->task); kfree(worker); - spin_lock_irq(&gcwq->lock); + spin_lock_irq(&pool->lock); ida_remove(&pool->worker_ida, id); } static void idle_worker_timeout(unsigned long __pool) { struct worker_pool *pool = (void *)__pool; - struct global_cwq *gcwq = pool->gcwq; - spin_lock_irq(&gcwq->lock); + spin_lock_irq(&pool->lock); if (too_many_workers(pool)) { struct worker *worker; @@ -1923,7 +1914,7 @@ static void idle_worker_timeout(unsigned long __pool) } } - spin_unlock_irq(&gcwq->lock); + spin_unlock_irq(&pool->lock); } static bool send_mayday(struct work_struct *work) @@ -1948,10 +1939,9 @@ static bool send_mayday(struct work_struct *work) static void gcwq_mayday_timeout(unsigned long __pool) { struct worker_pool *pool = (void *)__pool; - struct global_cwq *gcwq = pool->gcwq; struct work_struct *work; - spin_lock_irq(&gcwq->lock); + spin_lock_irq(&pool->lock); if (need_to_create_worker(pool)) { /* @@ -1964,7 +1954,7 @@ static void gcwq_mayday_timeout(unsigned long __pool) send_mayday(work); } - spin_unlock_irq(&gcwq->lock); + spin_unlock_irq(&pool->lock); mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INTERVAL); } @@ -1983,24 +1973,22 @@ static void gcwq_mayday_timeout(unsigned long __pool) * may_start_working() true. * * LOCKING: - * spin_lock_irq(gcwq->lock) which may be released and regrabbed + * spin_lock_irq(pool->lock) which may be released and regrabbed * multiple times. Does GFP_KERNEL allocations. Called only from * manager. * * RETURNS: - * false if no action was taken and gcwq->lock stayed locked, true + * false if no action was taken and pool->lock stayed locked, true * otherwise. */ static bool maybe_create_worker(struct worker_pool *pool) -__releases(&gcwq->lock) -__acquires(&gcwq->lock) +__releases(&pool->lock) +__acquires(&pool->lock) { - struct global_cwq *gcwq = pool->gcwq; - if (!need_to_create_worker(pool)) return false; restart: - spin_unlock_irq(&gcwq->lock); + spin_unlock_irq(&pool->lock); /* if we don't make progress in MAYDAY_INITIAL_TIMEOUT, call for help */ mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INITIAL_TIMEOUT); @@ -2011,7 +1999,7 @@ restart: worker = create_worker(pool); if (worker) { del_timer_sync(&pool->mayday_timer); - spin_lock_irq(&gcwq->lock); + spin_lock_irq(&pool->lock); start_worker(worker); BUG_ON(need_to_create_worker(pool)); return true; @@ -2028,7 +2016,7 @@ restart: } del_timer_sync(&pool->mayday_timer); - spin_lock_irq(&gcwq->lock); + spin_lock_irq(&pool->lock); if (need_to_create_worker(pool)) goto restart; return true; @@ -2042,11 +2030,11 @@ restart: * IDLE_WORKER_TIMEOUT. * * LOCKING: - * spin_lock_irq(gcwq->lock) which may be released and regrabbed + * spin_lock_irq(pool->lock) which may be released and regrabbed * multiple times. Called only from manager. * * RETURNS: - * false if no action was taken and gcwq->lock stayed locked, true + * false if no action was taken and pool->lock stayed locked, true * otherwise. */ static bool maybe_destroy_workers(struct worker_pool *pool) @@ -2085,12 +2073,12 @@ static bool maybe_destroy_workers(struct worker_pool *pool) * and may_start_working() is true. * * CONTEXT: - * spin_lock_irq(gcwq->lock) which may be released and regrabbed + * spin_lock_irq(pool->lock) which may be released and regrabbed * multiple times. Does GFP_KERNEL allocations. * * RETURNS: - * false if no action was taken and gcwq->lock stayed locked, true if - * some action was taken. + * spin_lock_irq(pool->lock) which may be released and regrabbed + * multiple times. Does GFP_KERNEL allocations. */ static bool manage_workers(struct worker *worker) { @@ -2112,10 +2100,10 @@ static bool manage_workers(struct worker *worker) * manager against CPU hotplug. * * assoc_mutex would always be free unless CPU hotplug is in - * progress. trylock first without dropping @gcwq->lock. + * progress. trylock first without dropping @pool->lock. */ if (unlikely(!mutex_trylock(&pool->assoc_mutex))) { - spin_unlock_irq(&pool->gcwq->lock); + spin_unlock_irq(&pool->lock); mutex_lock(&pool->assoc_mutex); /* * CPU hotplug could have happened while we were waiting @@ -2162,15 +2150,14 @@ static bool manage_workers(struct worker *worker) * call this function to process a work. * * CONTEXT: - * spin_lock_irq(gcwq->lock) which is released and regrabbed. + * spin_lock_irq(pool->lock) which is released and regrabbed. */ static void process_one_work(struct worker *worker, struct work_struct *work) -__releases(&gcwq->lock) -__acquires(&gcwq->lock) +__releases(&pool->lock) +__acquires(&pool->lock) { struct cpu_workqueue_struct *cwq = get_work_cwq(work); struct worker_pool *pool = worker->pool; - struct global_cwq *gcwq = pool->gcwq; bool cpu_intensive = cwq->wq->flags & WQ_CPU_INTENSIVE; int work_color; struct worker *collision; @@ -2225,7 +2212,7 @@ __acquires(&gcwq->lock) worker_set_flags(worker, WORKER_CPU_INTENSIVE, true); /* - * Unbound gcwq isn't concurrency managed and work items should be + * Unbound pool isn't concurrency managed and work items should be * executed ASAP. Wake up another worker if necessary. */ if ((worker->flags & WORKER_UNBOUND) && need_more_worker(pool)) @@ -2233,13 +2220,13 @@ __acquires(&gcwq->lock) /* * Record the last pool and clear PENDING which should be the last - * update to @work. Also, do this inside @gcwq->lock so that + * update to @work. Also, do this inside @pool->lock so that * PENDING and queued state changes happen together while IRQ is * disabled. */ set_work_pool_and_clear_pending(work, pool->id); - spin_unlock_irq(&gcwq->lock); + spin_unlock_irq(&pool->lock); lock_map_acquire_read(&cwq->wq->lockdep_map); lock_map_acquire(&lockdep_map); @@ -2262,7 +2249,7 @@ __acquires(&gcwq->lock) dump_stack(); } - spin_lock_irq(&gcwq->lock); + spin_lock_irq(&pool->lock); /* clear cpu intensive status */ if (unlikely(cpu_intensive)) @@ -2285,7 +2272,7 @@ __acquires(&gcwq->lock) * fetches a work from the top and executes it. * * CONTEXT: - * spin_lock_irq(gcwq->lock) which may be released and regrabbed + * spin_lock_irq(pool->lock) which may be released and regrabbed * multiple times. */ static void process_scheduled_works(struct worker *worker) @@ -2311,16 +2298,15 @@ static int worker_thread(void *__worker) { struct worker *worker = __worker; struct worker_pool *pool = worker->pool; - struct global_cwq *gcwq = pool->gcwq; /* tell the scheduler that this is a workqueue worker */ worker->task->flags |= PF_WQ_WORKER; woke_up: - spin_lock_irq(&gcwq->lock); + spin_lock_irq(&pool->lock); /* we are off idle list if destruction or rebind is requested */ if (unlikely(list_empty(&worker->entry))) { - spin_unlock_irq(&gcwq->lock); + spin_unlock_irq(&pool->lock); /* if DIE is set, destruction is requested */ if (worker->flags & WORKER_DIE) { @@ -2379,15 +2365,15 @@ sleep: goto recheck; /* - * gcwq->lock is held and there's no work to process and no - * need to manage, sleep. Workers are woken up only while - * holding gcwq->lock or from local cpu, so setting the - * current state before releasing gcwq->lock is enough to - * prevent losing any event. + * pool->lock is held and there's no work to process and no need to + * manage, sleep. Workers are woken up only while holding + * pool->lock or from local cpu, so setting the current state + * before releasing pool->lock is enough to prevent losing any + * event. */ worker_enter_idle(worker); __set_current_state(TASK_INTERRUPTIBLE); - spin_unlock_irq(&gcwq->lock); + spin_unlock_irq(&pool->lock); schedule(); goto woke_up; } @@ -2443,7 +2429,6 @@ repeat: unsigned int tcpu = is_unbound ? WORK_CPU_UNBOUND : cpu; struct cpu_workqueue_struct *cwq = get_cwq(tcpu, wq); struct worker_pool *pool = cwq->pool; - struct global_cwq *gcwq = pool->gcwq; struct work_struct *work, *n; __set_current_state(TASK_RUNNING); @@ -2465,14 +2450,14 @@ repeat: process_scheduled_works(rescuer); /* - * Leave this gcwq. If keep_working() is %true, notify a + * Leave this pool. If keep_working() is %true, notify a * regular worker; otherwise, we end up with 0 concurrency * and stalling the execution. */ if (keep_working(pool)) wake_up_worker(pool); - spin_unlock_irq(&gcwq->lock); + spin_unlock_irq(&pool->lock); } /* rescuers should never participate in concurrency management */ @@ -2514,7 +2499,7 @@ static void wq_barrier_func(struct work_struct *work) * underneath us, so we can't reliably determine cwq from @target. * * CONTEXT: - * spin_lock_irq(gcwq->lock). + * spin_lock_irq(pool->lock). */ static void insert_wq_barrier(struct cpu_workqueue_struct *cwq, struct wq_barrier *barr, @@ -2524,7 +2509,7 @@ static void insert_wq_barrier(struct cpu_workqueue_struct *cwq, unsigned int linked = 0; /* - * debugobject calls are safe here even with gcwq->lock locked + * debugobject calls are safe here even with pool->lock locked * as we know for sure that this will not trigger any of the * checks and call back into the fixup functions where we * might deadlock. @@ -2597,9 +2582,9 @@ static bool flush_workqueue_prep_cwqs(struct workqueue_struct *wq, for_each_cwq_cpu(cpu, wq) { struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); - struct global_cwq *gcwq = cwq->pool->gcwq; + struct worker_pool *pool = cwq->pool; - spin_lock_irq(&gcwq->lock); + spin_lock_irq(&pool->lock); if (flush_color >= 0) { BUG_ON(cwq->flush_color != -1); @@ -2616,7 +2601,7 @@ static bool flush_workqueue_prep_cwqs(struct workqueue_struct *wq, cwq->work_color = work_color; } - spin_unlock_irq(&gcwq->lock); + spin_unlock_irq(&pool->lock); } if (flush_color >= 0 && atomic_dec_and_test(&wq->nr_cwqs_to_flush)) @@ -2813,9 +2798,9 @@ reflush: struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); bool drained; - spin_lock_irq(&cwq->pool->gcwq->lock); + spin_lock_irq(&cwq->pool->lock); drained = !cwq->nr_active && list_empty(&cwq->delayed_works); - spin_unlock_irq(&cwq->pool->gcwq->lock); + spin_unlock_irq(&cwq->pool->lock); if (drained) continue; @@ -2838,25 +2823,23 @@ static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr) { struct worker *worker = NULL; struct worker_pool *pool; - struct global_cwq *gcwq; struct cpu_workqueue_struct *cwq; might_sleep(); pool = get_work_pool(work); if (!pool) return false; - gcwq = pool->gcwq; - spin_lock_irq(&gcwq->lock); + spin_lock_irq(&pool->lock); if (!list_empty(&work->entry)) { /* * See the comment near try_to_grab_pending()->smp_rmb(). - * If it was re-queued to a different gcwq under us, we + * If it was re-queued to a different pool under us, we * are not going to wait. */ smp_rmb(); cwq = get_work_cwq(work); - if (unlikely(!cwq || gcwq != cwq->pool->gcwq)) + if (unlikely(!cwq || pool != cwq->pool)) goto already_gone; } else { worker = find_worker_executing_work(pool, work); @@ -2866,7 +2849,7 @@ static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr) } insert_wq_barrier(cwq, barr, work, worker); - spin_unlock_irq(&gcwq->lock); + spin_unlock_irq(&pool->lock); /* * If @max_active is 1 or rescuer is in use, flushing another work @@ -2882,7 +2865,7 @@ static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr) return true; already_gone: - spin_unlock_irq(&gcwq->lock); + spin_unlock_irq(&pool->lock); return false; } @@ -3404,7 +3387,7 @@ EXPORT_SYMBOL_GPL(destroy_workqueue); * increased. * * CONTEXT: - * spin_lock_irq(gcwq->lock). + * spin_lock_irq(pool->lock). */ static void cwq_set_max_active(struct cpu_workqueue_struct *cwq, int max_active) { @@ -3438,15 +3421,14 @@ void workqueue_set_max_active(struct workqueue_struct *wq, int max_active) for_each_cwq_cpu(cpu, wq) { struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); struct worker_pool *pool = cwq->pool; - struct global_cwq *gcwq = pool->gcwq; - spin_lock_irq(&gcwq->lock); + spin_lock_irq(&pool->lock); if (!(wq->flags & WQ_FREEZABLE) || !(pool->flags & POOL_FREEZING)) cwq_set_max_active(cwq, max_active); - spin_unlock_irq(&gcwq->lock); + spin_unlock_irq(&pool->lock); } spin_unlock(&workqueue_lock); @@ -3489,22 +3471,20 @@ EXPORT_SYMBOL_GPL(workqueue_congested); unsigned int work_busy(struct work_struct *work) { struct worker_pool *pool = get_work_pool(work); - struct global_cwq *gcwq; unsigned long flags; unsigned int ret = 0; if (!pool) return 0; - gcwq = pool->gcwq; - spin_lock_irqsave(&gcwq->lock, flags); + spin_lock_irqsave(&pool->lock, flags); if (work_pending(work)) ret |= WORK_BUSY_PENDING; if (find_worker_executing_work(pool, work)) ret |= WORK_BUSY_RUNNING; - spin_unlock_irqrestore(&gcwq->lock, flags); + spin_unlock_irqrestore(&pool->lock, flags); return ret; } @@ -3532,7 +3512,10 @@ static void gcwq_claim_assoc_and_lock(struct global_cwq *gcwq) for_each_worker_pool(pool, gcwq) mutex_lock_nested(&pool->assoc_mutex, pool - gcwq->pools); - spin_lock_irq(&gcwq->lock); + + local_irq_disable(); + for_each_worker_pool(pool, gcwq) + spin_lock_nested(&pool->lock, pool - gcwq->pools); } /* release manager positions */ @@ -3540,7 +3523,10 @@ static void gcwq_release_assoc_and_unlock(struct global_cwq *gcwq) { struct worker_pool *pool; - spin_unlock_irq(&gcwq->lock); + for_each_worker_pool(pool, gcwq) + spin_unlock(&pool->lock); + local_irq_enable(); + for_each_worker_pool(pool, gcwq) mutex_unlock(&pool->assoc_mutex); } @@ -3621,9 +3607,9 @@ static int __cpuinit workqueue_cpu_up_callback(struct notifier_block *nfb, if (!worker) return NOTIFY_BAD; - spin_lock_irq(&gcwq->lock); + spin_lock_irq(&pool->lock); start_worker(worker); - spin_unlock_irq(&gcwq->lock); + spin_unlock_irq(&pool->lock); } break; @@ -3709,7 +3695,7 @@ EXPORT_SYMBOL_GPL(work_on_cpu); * gcwq->worklist. * * CONTEXT: - * Grabs and releases workqueue_lock and gcwq->lock's. + * Grabs and releases workqueue_lock and pool->lock's. */ void freeze_workqueues_begin(void) { @@ -3725,9 +3711,11 @@ void freeze_workqueues_begin(void) struct worker_pool *pool; struct workqueue_struct *wq; - spin_lock_irq(&gcwq->lock); + local_irq_disable(); for_each_worker_pool(pool, gcwq) { + spin_lock_nested(&pool->lock, pool - gcwq->pools); + WARN_ON_ONCE(pool->flags & POOL_FREEZING); pool->flags |= POOL_FREEZING; } @@ -3739,7 +3727,9 @@ void freeze_workqueues_begin(void) cwq->max_active = 0; } - spin_unlock_irq(&gcwq->lock); + for_each_worker_pool(pool, gcwq) + spin_unlock(&pool->lock); + local_irq_enable(); } spin_unlock(&workqueue_lock); @@ -3798,7 +3788,7 @@ out_unlock: * frozen works are transferred to their respective gcwq worklists. * * CONTEXT: - * Grabs and releases workqueue_lock and gcwq->lock's. + * Grabs and releases workqueue_lock and pool->lock's. */ void thaw_workqueues(void) { @@ -3814,9 +3804,11 @@ void thaw_workqueues(void) struct worker_pool *pool; struct workqueue_struct *wq; - spin_lock_irq(&gcwq->lock); + local_irq_disable(); for_each_worker_pool(pool, gcwq) { + spin_lock_nested(&pool->lock, pool - gcwq->pools); + WARN_ON_ONCE(!(pool->flags & POOL_FREEZING)); pool->flags &= ~POOL_FREEZING; } @@ -3831,10 +3823,11 @@ void thaw_workqueues(void) cwq_set_max_active(cwq, wq->saved_max_active); } - for_each_worker_pool(pool, gcwq) + for_each_worker_pool(pool, gcwq) { wake_up_worker(pool); - - spin_unlock_irq(&gcwq->lock); + spin_unlock(&pool->lock); + } + local_irq_enable(); } workqueue_freezing = false; @@ -3859,10 +3852,9 @@ static int __init init_workqueues(void) struct global_cwq *gcwq = get_gcwq(cpu); struct worker_pool *pool; - spin_lock_init(&gcwq->lock); - for_each_worker_pool(pool, gcwq) { pool->gcwq = gcwq; + spin_lock_init(&pool->lock); pool->cpu = cpu; pool->flags |= POOL_DISASSOCIATED; INIT_LIST_HEAD(&pool->worklist); @@ -3897,9 +3889,9 @@ static int __init init_workqueues(void) worker = create_worker(pool); BUG_ON(!worker); - spin_lock_irq(&gcwq->lock); + spin_lock_irq(&pool->lock); start_worker(worker); - spin_unlock_irq(&gcwq->lock); + spin_unlock_irq(&pool->lock); } } |