diff options
-rw-r--r-- | include/linux/workqueue.h | 38 | ||||
-rw-r--r-- | include/trace/events/workqueue.h | 77 | ||||
-rw-r--r-- | kernel/workqueue.c | 274 |
3 files changed, 275 insertions, 114 deletions
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h index 25e02c941bac..e33ff4a91703 100644 --- a/include/linux/workqueue.h +++ b/include/linux/workqueue.h @@ -306,6 +306,24 @@ __alloc_workqueue_key(const char *name, unsigned int flags, int max_active, __alloc_workqueue_key((name), (flags), (max_active), NULL, NULL) #endif +/** + * alloc_ordered_workqueue - allocate an ordered workqueue + * @name: name of the workqueue + * @flags: WQ_* flags (only WQ_FREEZEABLE and WQ_RESCUER are meaningful) + * + * Allocate an ordered workqueue. An ordered workqueue executes at + * most one work item at any given time in the queued order. They are + * implemented as unbound workqueues with @max_active of one. + * + * RETURNS: + * Pointer to the allocated workqueue on success, %NULL on failure. + */ +static inline struct workqueue_struct * +alloc_ordered_workqueue(const char *name, unsigned int flags) +{ + return alloc_workqueue(name, WQ_UNBOUND | flags, 1); +} + #define create_workqueue(name) \ alloc_workqueue((name), WQ_RESCUER, 1) #define create_freezeable_workqueue(name) \ @@ -325,7 +343,6 @@ extern int queue_delayed_work_on(int cpu, struct workqueue_struct *wq, extern void flush_workqueue(struct workqueue_struct *wq); extern void flush_scheduled_work(void); -extern void flush_delayed_work(struct delayed_work *work); extern int schedule_work(struct work_struct *work); extern int schedule_work_on(int cpu, struct work_struct *work); @@ -337,8 +354,13 @@ extern int keventd_up(void); int execute_in_process_context(work_func_t fn, struct execute_work *); -extern int flush_work(struct work_struct *work); -extern int cancel_work_sync(struct work_struct *work); +extern bool flush_work(struct work_struct *work); +extern bool flush_work_sync(struct work_struct *work); +extern bool cancel_work_sync(struct work_struct *work); + +extern bool flush_delayed_work(struct delayed_work *dwork); +extern bool flush_delayed_work_sync(struct delayed_work *work); +extern bool cancel_delayed_work_sync(struct delayed_work *dwork); extern void workqueue_set_max_active(struct workqueue_struct *wq, int max_active); @@ -352,9 +374,9 @@ extern unsigned int work_busy(struct work_struct *work); * it returns 1 and the work doesn't re-arm itself. Run flush_workqueue() or * cancel_work_sync() to wait on it. */ -static inline int cancel_delayed_work(struct delayed_work *work) +static inline bool cancel_delayed_work(struct delayed_work *work) { - int ret; + bool ret; ret = del_timer_sync(&work->timer); if (ret) @@ -367,9 +389,9 @@ static inline int cancel_delayed_work(struct delayed_work *work) * if it returns 0 the timer function may be running and the queueing is in * progress. */ -static inline int __cancel_delayed_work(struct delayed_work *work) +static inline bool __cancel_delayed_work(struct delayed_work *work) { - int ret; + bool ret; ret = del_timer(&work->timer); if (ret) @@ -377,8 +399,6 @@ static inline int __cancel_delayed_work(struct delayed_work *work) return ret; } -extern int cancel_delayed_work_sync(struct delayed_work *work); - /* Obsolete. use cancel_delayed_work_sync() */ static inline void cancel_rearming_delayed_workqueue(struct workqueue_struct *wq, diff --git a/include/trace/events/workqueue.h b/include/trace/events/workqueue.h index 49682d7e9d60..7d497291c85d 100644 --- a/include/trace/events/workqueue.h +++ b/include/trace/events/workqueue.h @@ -7,38 +7,83 @@ #include <linux/tracepoint.h> #include <linux/workqueue.h> +DECLARE_EVENT_CLASS(workqueue_work, + + TP_PROTO(struct work_struct *work), + + TP_ARGS(work), + + TP_STRUCT__entry( + __field( void *, work ) + ), + + TP_fast_assign( + __entry->work = work; + ), + + TP_printk("work struct %p", __entry->work) +); + /** - * workqueue_execute_start - called immediately before the workqueue callback + * workqueue_queue_work - called when a work gets queued + * @req_cpu: the requested cpu + * @cwq: pointer to struct cpu_workqueue_struct * @work: pointer to struct work_struct * - * Allows to track workqueue execution. + * This event occurs when a work is queued immediately or once a + * delayed work is actually queued on a workqueue (ie: once the delay + * has been reached). */ -TRACE_EVENT(workqueue_execute_start, +TRACE_EVENT(workqueue_queue_work, - TP_PROTO(struct work_struct *work), + TP_PROTO(unsigned int req_cpu, struct cpu_workqueue_struct *cwq, + struct work_struct *work), - TP_ARGS(work), + TP_ARGS(req_cpu, cwq, work), TP_STRUCT__entry( __field( void *, work ) __field( void *, function) + __field( void *, workqueue) + __field( unsigned int, req_cpu ) + __field( unsigned int, cpu ) ), TP_fast_assign( __entry->work = work; __entry->function = work->func; + __entry->workqueue = cwq->wq; + __entry->req_cpu = req_cpu; + __entry->cpu = cwq->gcwq->cpu; ), - TP_printk("work struct %p: function %pf", __entry->work, __entry->function) + TP_printk("work struct=%p function=%pf workqueue=%p req_cpu=%u cpu=%u", + __entry->work, __entry->function, __entry->workqueue, + __entry->req_cpu, __entry->cpu) ); /** - * workqueue_execute_end - called immediately before the workqueue callback + * workqueue_activate_work - called when a work gets activated + * @work: pointer to struct work_struct + * + * This event occurs when a queued work is put on the active queue, + * which happens immediately after queueing unless @max_active limit + * is reached. + */ +DEFINE_EVENT(workqueue_work, workqueue_activate_work, + + TP_PROTO(struct work_struct *work), + + TP_ARGS(work) +); + +/** + * workqueue_execute_start - called immediately before the workqueue callback * @work: pointer to struct work_struct * * Allows to track workqueue execution. */ -TRACE_EVENT(workqueue_execute_end, +TRACE_EVENT(workqueue_execute_start, TP_PROTO(struct work_struct *work), @@ -46,15 +91,29 @@ TRACE_EVENT(workqueue_execute_end, TP_STRUCT__entry( __field( void *, work ) + __field( void *, function) ), TP_fast_assign( __entry->work = work; + __entry->function = work->func; ), - TP_printk("work struct %p", __entry->work) + TP_printk("work struct %p: function %pf", __entry->work, __entry->function) ); +/** + * workqueue_execute_end - called immediately before the workqueue callback + * @work: pointer to struct work_struct + * + * Allows to track workqueue execution. + */ +DEFINE_EVENT(workqueue_work, workqueue_execute_end, + + TP_PROTO(struct work_struct *work), + + TP_ARGS(work) +); #endif /* _TRACE_WORKQUEUE_H */ diff --git a/kernel/workqueue.c b/kernel/workqueue.c index f77afd939229..cb2ccfbed0c6 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -42,9 +42,6 @@ #include <linux/lockdep.h> #include <linux/idr.h> -#define CREATE_TRACE_POINTS -#include <trace/events/workqueue.h> - #include "workqueue_sched.h" enum { @@ -257,6 +254,9 @@ EXPORT_SYMBOL_GPL(system_long_wq); EXPORT_SYMBOL_GPL(system_nrt_wq); EXPORT_SYMBOL_GPL(system_unbound_wq); +#define CREATE_TRACE_POINTS +#include <trace/events/workqueue.h> + #define for_each_busy_worker(worker, i, pos, gcwq) \ for (i = 0; i < BUSY_WORKER_HASH_SIZE; i++) \ hlist_for_each_entry(worker, pos, &gcwq->busy_hash[i], hentry) @@ -997,6 +997,7 @@ static void __queue_work(unsigned int cpu, struct workqueue_struct *wq, /* gcwq determined, get cwq and queue */ cwq = get_cwq(gcwq->cpu, wq); + trace_workqueue_queue_work(cpu, cwq, work); BUG_ON(!list_empty(&work->entry)); @@ -1004,6 +1005,7 @@ static void __queue_work(unsigned int cpu, struct workqueue_struct *wq, work_flags = work_color_to_flags(cwq->work_color); if (likely(cwq->nr_active < cwq->max_active)) { + trace_workqueue_activate_work(work); cwq->nr_active++; worklist = gcwq_determine_ins_pos(gcwq, cwq); } else { @@ -1679,6 +1681,7 @@ static void cwq_activate_first_delayed(struct cpu_workqueue_struct *cwq) struct work_struct, entry); struct list_head *pos = gcwq_determine_ins_pos(cwq->gcwq, cwq); + trace_workqueue_activate_work(work); move_linked_works(work, pos, NULL); __clear_bit(WORK_STRUCT_DELAYED_BIT, work_data_bits(work)); cwq->nr_active++; @@ -2326,27 +2329,17 @@ out_unlock: } EXPORT_SYMBOL_GPL(flush_workqueue); -/** - * flush_work - block until a work_struct's callback has terminated - * @work: the work which is to be flushed - * - * Returns false if @work has already terminated. - * - * It is expected that, prior to calling flush_work(), the caller has - * arranged for the work to not be requeued, otherwise it doesn't make - * sense to use this function. - */ -int flush_work(struct work_struct *work) +static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr, + bool wait_executing) { struct worker *worker = NULL; struct global_cwq *gcwq; struct cpu_workqueue_struct *cwq; - struct wq_barrier barr; might_sleep(); gcwq = get_work_gcwq(work); if (!gcwq) - return 0; + return false; spin_lock_irq(&gcwq->lock); if (!list_empty(&work->entry)) { @@ -2359,28 +2352,127 @@ int flush_work(struct work_struct *work) cwq = get_work_cwq(work); if (unlikely(!cwq || gcwq != cwq->gcwq)) goto already_gone; - } else { + } else if (wait_executing) { worker = find_worker_executing_work(gcwq, work); if (!worker) goto already_gone; cwq = worker->current_cwq; - } + } else + goto already_gone; - insert_wq_barrier(cwq, &barr, work, worker); + insert_wq_barrier(cwq, barr, work, worker); spin_unlock_irq(&gcwq->lock); lock_map_acquire(&cwq->wq->lockdep_map); lock_map_release(&cwq->wq->lockdep_map); - - wait_for_completion(&barr.done); - destroy_work_on_stack(&barr.work); - return 1; + return true; already_gone: spin_unlock_irq(&gcwq->lock); - return 0; + return false; +} + +/** + * flush_work - wait for a work to finish executing the last queueing instance + * @work: the work to flush + * + * Wait until @work has finished execution. This function considers + * only the last queueing instance of @work. If @work has been + * enqueued across different CPUs on a non-reentrant workqueue or on + * multiple workqueues, @work might still be executing on return on + * some of the CPUs from earlier queueing. + * + * If @work was queued only on a non-reentrant, ordered or unbound + * workqueue, @work is guaranteed to be idle on return if it hasn't + * been requeued since flush started. + * + * RETURNS: + * %true if flush_work() waited for the work to finish execution, + * %false if it was already idle. + */ +bool flush_work(struct work_struct *work) +{ + struct wq_barrier barr; + + if (start_flush_work(work, &barr, true)) { + wait_for_completion(&barr.done); + destroy_work_on_stack(&barr.work); + return true; + } else + return false; } EXPORT_SYMBOL_GPL(flush_work); +static bool wait_on_cpu_work(struct global_cwq *gcwq, struct work_struct *work) +{ + struct wq_barrier barr; + struct worker *worker; + + spin_lock_irq(&gcwq->lock); + + worker = find_worker_executing_work(gcwq, work); + if (unlikely(worker)) + insert_wq_barrier(worker->current_cwq, &barr, work, worker); + + spin_unlock_irq(&gcwq->lock); + + if (unlikely(worker)) { + wait_for_completion(&barr.done); + destroy_work_on_stack(&barr.work); + return true; + } else + return false; +} + +static bool wait_on_work(struct work_struct *work) +{ + bool ret = false; + int cpu; + + might_sleep(); + + lock_map_acquire(&work->lockdep_map); + lock_map_release(&work->lockdep_map); + + for_each_gcwq_cpu(cpu) + ret |= wait_on_cpu_work(get_gcwq(cpu), work); + return ret; +} + +/** + * flush_work_sync - wait until a work has finished execution + * @work: the work to flush + * + * Wait until @work has finished execution. On return, it's + * guaranteed that all queueing instances of @work which happened + * before this function is called are finished. In other words, if + * @work hasn't been requeued since this function was called, @work is + * guaranteed to be idle on return. + * + * RETURNS: + * %true if flush_work_sync() waited for the work to finish execution, + * %false if it was already idle. + */ +bool flush_work_sync(struct work_struct *work) +{ + struct wq_barrier barr; + bool pending, waited; + + /* we'll wait for executions separately, queue barr only if pending */ + pending = start_flush_work(work, &barr, false); + + /* wait for executions to finish */ + waited = wait_on_work(work); + + /* wait for the pending one */ + if (pending) { + wait_for_completion(&barr.done); + destroy_work_on_stack(&barr.work); + } + + return pending || waited; +} +EXPORT_SYMBOL_GPL(flush_work_sync); + /* * Upon a successful return (>= 0), the caller "owns" WORK_STRUCT_PENDING bit, * so this work can't be re-armed in any way. @@ -2423,39 +2515,7 @@ static int try_to_grab_pending(struct work_struct *work) return ret; } -static void wait_on_cpu_work(struct global_cwq *gcwq, struct work_struct *work) -{ - struct wq_barrier barr; - struct worker *worker; - - spin_lock_irq(&gcwq->lock); - - worker = find_worker_executing_work(gcwq, work); - if (unlikely(worker)) - insert_wq_barrier(worker->current_cwq, &barr, work, worker); - - spin_unlock_irq(&gcwq->lock); - - if (unlikely(worker)) { - wait_for_completion(&barr.done); - destroy_work_on_stack(&barr.work); - } -} - -static void wait_on_work(struct work_struct *work) -{ - int cpu; - - might_sleep(); - - lock_map_acquire(&work->lockdep_map); - lock_map_release(&work->lockdep_map); - - for_each_gcwq_cpu(cpu) - wait_on_cpu_work(get_gcwq(cpu), work); -} - -static int __cancel_work_timer(struct work_struct *work, +static bool __cancel_work_timer(struct work_struct *work, struct timer_list* timer) { int ret; @@ -2472,42 +2532,81 @@ static int __cancel_work_timer(struct work_struct *work, } /** - * cancel_work_sync - block until a work_struct's callback has terminated - * @work: the work which is to be flushed + * cancel_work_sync - cancel a work and wait for it to finish + * @work: the work to cancel * - * Returns true if @work was pending. + * Cancel @work and wait for its execution to finish. This function + * can be used even if the work re-queues itself or migrates to + * another workqueue. On return from this function, @work is + * guaranteed to be not pending or executing on any CPU. * - * cancel_work_sync() will cancel the work if it is queued. If the work's - * callback appears to be running, cancel_work_sync() will block until it - * has completed. + * cancel_work_sync(&delayed_work->work) must not be used for + * delayed_work's. Use cancel_delayed_work_sync() instead. * - * It is possible to use this function if the work re-queues itself. It can - * cancel the work even if it migrates to another workqueue, however in that - * case it only guarantees that work->func() has completed on the last queued - * workqueue. - * - * cancel_work_sync(&delayed_work->work) should be used only if ->timer is not - * pending, otherwise it goes into a busy-wait loop until the timer expires. - * - * The caller must ensure that workqueue_struct on which this work was last + * The caller must ensure that the workqueue on which @work was last * queued can't be destroyed before this function returns. + * + * RETURNS: + * %true if @work was pending, %false otherwise. */ -int cancel_work_sync(struct work_struct *work) +bool cancel_work_sync(struct work_struct *work) { return __cancel_work_timer(work, NULL); } EXPORT_SYMBOL_GPL(cancel_work_sync); /** - * cancel_delayed_work_sync - reliably kill off a delayed work. - * @dwork: the delayed work struct + * flush_delayed_work - wait for a dwork to finish executing the last queueing + * @dwork: the delayed work to flush * - * Returns true if @dwork was pending. + * Delayed timer is cancelled and the pending work is queued for + * immediate execution. Like flush_work(), this function only + * considers the last queueing instance of @dwork. * - * It is possible to use this function if @dwork rearms itself via queue_work() - * or queue_delayed_work(). See also the comment for cancel_work_sync(). + * RETURNS: + * %true if flush_work() waited for the work to finish execution, + * %false if it was already idle. */ -int cancel_delayed_work_sync(struct delayed_work *dwork) +bool flush_delayed_work(struct delayed_work *dwork) +{ + if (del_timer_sync(&dwork->timer)) + __queue_work(raw_smp_processor_id(), + get_work_cwq(&dwork->work)->wq, &dwork->work); + return flush_work(&dwork->work); +} +EXPORT_SYMBOL(flush_delayed_work); + +/** + * flush_delayed_work_sync - wait for a dwork to finish + * @dwork: the delayed work to flush + * + * Delayed timer is cancelled and the pending work is queued for + * execution immediately. Other than timer handling, its behavior + * is identical to flush_work_sync(). + * + * RETURNS: + * %true if flush_work_sync() waited for the work to finish execution, + * %false if it was already idle. + */ +bool flush_delayed_work_sync(struct delayed_work *dwork) +{ + if (del_timer_sync(&dwork->timer)) + __queue_work(raw_smp_processor_id(), + get_work_cwq(&dwork->work)->wq, &dwork->work); + return flush_work_sync(&dwork->work); +} +EXPORT_SYMBOL(flush_delayed_work_sync); + +/** + * cancel_delayed_work_sync - cancel a delayed work and wait for it to finish + * @dwork: the delayed work cancel + * + * This is cancel_work_sync() for delayed works. + * + * RETURNS: + * %true if @dwork was pending, %false otherwise. + */ +bool cancel_delayed_work_sync(struct delayed_work *dwork) { return __cancel_work_timer(&dwork->work, &dwork->timer); } @@ -2559,23 +2658,6 @@ int schedule_delayed_work(struct delayed_work *dwork, EXPORT_SYMBOL(schedule_delayed_work); /** - * flush_delayed_work - block until a dwork_struct's callback has terminated - * @dwork: the delayed work which is to be flushed - * - * Any timeout is cancelled, and any pending work is run immediately. - */ -void flush_delayed_work(struct delayed_work *dwork) -{ - if (del_timer_sync(&dwork->timer)) { - __queue_work(get_cpu(), get_work_cwq(&dwork->work)->wq, - &dwork->work); - put_cpu(); - } - flush_work(&dwork->work); -} -EXPORT_SYMBOL(flush_delayed_work); - -/** * schedule_delayed_work_on - queue work in global workqueue on CPU after delay * @cpu: cpu to use * @dwork: job to be done |