diff options
| -rw-r--r-- | include/linux/workqueue.h | 5 | ||||
| -rw-r--r-- | kernel/workqueue.c | 131 |
2 files changed, 89 insertions, 47 deletions
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h index 0697946c66a..e724dafc9e6 100644 --- a/include/linux/workqueue.h +++ b/include/linux/workqueue.h @@ -96,9 +96,14 @@ struct execute_work { #ifdef CONFIG_DEBUG_OBJECTS_WORK extern void __init_work(struct work_struct *work, int onstack); extern void destroy_work_on_stack(struct work_struct *work); +static inline unsigned int work_static(struct work_struct *work) +{ + return *work_data_bits(work) & (1 << WORK_STRUCT_STATIC); +} #else static inline void __init_work(struct work_struct *work, int onstack) { } static inline void destroy_work_on_stack(struct work_struct *work) { } +static inline unsigned int work_static(struct work_struct *work) { return 0; } #endif /* diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 1a47fbf92fa..c56146a755e 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -37,6 +37,16 @@ #include <trace/events/workqueue.h> /* + * Structure fields follow one of the following exclusion rules. + * + * I: Set during initialization and read-only afterwards. + * + * L: cwq->lock protected. Access with cwq->lock held. + * + * W: workqueue_lock protected. + */ + +/* * The per-CPU workqueue (if single thread, we always use the first * possible cpu). */ @@ -48,8 +58,8 @@ struct cpu_workqueue_struct { wait_queue_head_t more_work; struct work_struct *current_work; - struct workqueue_struct *wq; - struct task_struct *thread; + struct workqueue_struct *wq; /* I: the owning workqueue */ + struct task_struct *thread; } ____cacheline_aligned; /* @@ -57,13 +67,13 @@ struct cpu_workqueue_struct { * per-CPU workqueues: */ struct workqueue_struct { - struct cpu_workqueue_struct *cpu_wq; - struct list_head list; - const char *name; + struct cpu_workqueue_struct *cpu_wq; /* I: cwq's */ + struct list_head list; /* W: list of all workqueues */ + const char *name; /* I: workqueue name */ int singlethread; int freezeable; /* Freeze threads during suspend */ #ifdef CONFIG_LOCKDEP - struct lockdep_map lockdep_map; + struct lockdep_map lockdep_map; #endif }; @@ -204,8 +214,8 @@ static const struct cpumask *wq_cpu_map(struct workqueue_struct *wq) ? cpu_singlethread_map : cpu_populated_map; } -static -struct cpu_workqueue_struct *wq_per_cpu(struct workqueue_struct *wq, int cpu) +static struct cpu_workqueue_struct *get_cwq(unsigned int cpu, + struct workqueue_struct *wq) { if (unlikely(is_wq_single_threaded(wq))) cpu = singlethread_cpu; @@ -217,15 +227,13 @@ struct cpu_workqueue_struct *wq_per_cpu(struct workqueue_struct *wq, int cpu) * - Must *only* be called if the pending flag is set */ static inline void set_wq_data(struct work_struct *work, - struct cpu_workqueue_struct *cwq) + struct cpu_workqueue_struct *cwq, + unsigned long extra_flags) { - unsigned long new; - BUG_ON(!work_pending(work)); - new = (unsigned long) cwq | (1UL << WORK_STRUCT_PENDING); - new |= WORK_STRUCT_FLAG_MASK & *work_data_bits(work); - atomic_long_set(&work->data, new); + atomic_long_set(&work->data, (unsigned long)cwq | work_static(work) | + (1UL << WORK_STRUCT_PENDING) | extra_flags); } /* @@ -233,9 +241,7 @@ static inline void set_wq_data(struct work_struct *work, */ static inline void clear_wq_data(struct work_struct *work) { - unsigned long flags = *work_data_bits(work) & - (1UL << WORK_STRUCT_STATIC); - atomic_long_set(&work->data, flags); + atomic_long_set(&work->data, work_static(work)); } static inline @@ -244,29 +250,47 @@ struct cpu_workqueue_struct *get_wq_data(struct work_struct *work) return (void *) (atomic_long_read(&work->data) & WORK_STRUCT_WQ_DATA_MASK); } +/** + * insert_work - insert a work into cwq + * @cwq: cwq @work belongs to + * @work: work to insert + * @head: insertion point + * @extra_flags: extra WORK_STRUCT_* flags to set + * + * Insert @work into @cwq after @head. + * + * CONTEXT: + * spin_lock_irq(cwq->lock). + */ static void insert_work(struct cpu_workqueue_struct *cwq, - struct work_struct *work, struct list_head *head) + struct work_struct *work, struct list_head *head, + unsigned int extra_flags) { trace_workqueue_insertion(cwq->thread, work); - set_wq_data(work, cwq); + /* we own @work, set data and link */ + set_wq_data(work, cwq, extra_flags); + /* * Ensure that we get the right work->data if we see the * result of list_add() below, see try_to_grab_pending(). */ smp_wmb(); + list_add_tail(&work->entry, head); wake_up(&cwq->more_work); } -static void __queue_work(struct cpu_workqueue_struct *cwq, +static void __queue_work(unsigned int cpu, struct workqueue_struct *wq, struct work_struct *work) { + struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); unsigned long flags; debug_work_activate(work); spin_lock_irqsave(&cwq->lock, flags); - insert_work(cwq, work, &cwq->worklist); + BUG_ON(!list_empty(&work->entry)); + insert_work(cwq, work, &cwq->worklist, 0); spin_unlock_irqrestore(&cwq->lock, flags); } @@ -308,8 +332,7 @@ queue_work_on(int cpu, struct workqueue_struct *wq, struct work_struct *work) int ret = 0; if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { - BUG_ON(!list_empty(&work->entry)); - __queue_work(wq_per_cpu(wq, cpu), work); + __queue_work(cpu, wq, work); ret = 1; } return ret; @@ -320,9 +343,8 @@ static void delayed_work_timer_fn(unsigned long __data) { struct delayed_work *dwork = (struct delayed_work *)__data; struct cpu_workqueue_struct *cwq = get_wq_data(&dwork->work); - struct workqueue_struct *wq = cwq->wq; - __queue_work(wq_per_cpu(wq, smp_processor_id()), &dwork->work); + __queue_work(smp_processor_id(), cwq->wq, &dwork->work); } /** @@ -366,7 +388,7 @@ int queue_delayed_work_on(int cpu, struct workqueue_struct *wq, timer_stats_timer_set_start_info(&dwork->timer); /* This stores cwq for the moment, for the timer_fn */ - set_wq_data(work, wq_per_cpu(wq, raw_smp_processor_id())); + set_wq_data(work, get_cwq(raw_smp_processor_id(), wq), 0); timer->expires = jiffies + delay; timer->data = (unsigned long)dwork; timer->function = delayed_work_timer_fn; @@ -430,6 +452,12 @@ static void run_workqueue(struct cpu_workqueue_struct *cwq) spin_unlock_irq(&cwq->lock); } +/** + * worker_thread - the worker thread function + * @__cwq: cwq to serve + * + * The cwq worker thread function. + */ static int worker_thread(void *__cwq) { struct cpu_workqueue_struct *cwq = __cwq; @@ -468,6 +496,17 @@ static void wq_barrier_func(struct work_struct *work) complete(&barr->done); } +/** + * insert_wq_barrier - insert a barrier work + * @cwq: cwq to insert barrier into + * @barr: wq_barrier to insert + * @head: insertion point + * + * Insert barrier @barr into @cwq before @head. + * + * CONTEXT: + * spin_lock_irq(cwq->lock). + */ static void insert_wq_barrier(struct cpu_workqueue_struct *cwq, struct wq_barrier *barr, struct list_head *head) { @@ -479,11 +518,10 @@ static void insert_wq_barrier(struct cpu_workqueue_struct *cwq, */ INIT_WORK_ON_STACK(&barr->work, wq_barrier_func); __set_bit(WORK_STRUCT_PENDING, work_data_bits(&barr->work)); - init_completion(&barr->done); debug_work_activate(&barr->work); - insert_work(cwq, &barr->work, head); + insert_work(cwq, &barr->work, head, 0); } static int flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) @@ -517,9 +555,6 @@ static int flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) * * We sleep until all works which were queued on entry have been handled, * but we are not livelocked by new incoming ones. - * - * This function used to run the workqueues itself. Now we just wait for the - * helper threads to do it. */ void flush_workqueue(struct workqueue_struct *wq) { @@ -558,7 +593,6 @@ int flush_work(struct work_struct *work) lock_map_acquire(&cwq->wq->lockdep_map); lock_map_release(&cwq->wq->lockdep_map); - prev = NULL; spin_lock_irq(&cwq->lock); if (!list_empty(&work->entry)) { /* @@ -567,22 +601,22 @@ int flush_work(struct work_struct *work) */ smp_rmb(); if (unlikely(cwq != get_wq_data(work))) - goto out; + goto already_gone; prev = &work->entry; } else { if (cwq->current_work != work) - goto out; + goto already_gone; prev = &cwq->worklist; } insert_wq_barrier(cwq, &barr, prev->next); -out: - spin_unlock_irq(&cwq->lock); - if (!prev) - return 0; + spin_unlock_irq(&cwq->lock); wait_for_completion(&barr.done); destroy_work_on_stack(&barr.work); return 1; +already_gone: + spin_unlock_irq(&cwq->lock); + return 0; } EXPORT_SYMBOL_GPL(flush_work); @@ -665,7 +699,7 @@ static void wait_on_work(struct work_struct *work) cpu_map = wq_cpu_map(wq); for_each_cpu(cpu, cpu_map) - wait_on_cpu_work(per_cpu_ptr(wq->cpu_wq, cpu), work); + wait_on_cpu_work(get_cwq(cpu, wq), work); } static int __cancel_work_timer(struct work_struct *work, @@ -782,9 +816,8 @@ EXPORT_SYMBOL(schedule_delayed_work); void flush_delayed_work(struct delayed_work *dwork) { if (del_timer_sync(&dwork->timer)) { - struct cpu_workqueue_struct *cwq; - cwq = wq_per_cpu(get_wq_data(&dwork->work)->wq, get_cpu()); - __queue_work(cwq, &dwork->work); + __queue_work(get_cpu(), get_wq_data(&dwork->work)->wq, + &dwork->work); put_cpu(); } flush_work(&dwork->work); @@ -991,13 +1024,11 @@ struct workqueue_struct *__create_workqueue_key(const char *name, wq = kzalloc(sizeof(*wq), GFP_KERNEL); if (!wq) - return NULL; + goto err; wq->cpu_wq = alloc_percpu(struct cpu_workqueue_struct); - if (!wq->cpu_wq) { - kfree(wq); - return NULL; - } + if (!wq->cpu_wq) + goto err; wq->name = name; lockdep_init_map(&wq->lockdep_map, lock_name, key, 0); @@ -1041,6 +1072,12 @@ struct workqueue_struct *__create_workqueue_key(const char *name, wq = NULL; } return wq; +err: + if (wq) { + free_percpu(wq->cpu_wq); + kfree(wq); + } + return NULL; } EXPORT_SYMBOL_GPL(__create_workqueue_key); |