diff options
| -rw-r--r-- | block/blk-throttle.c | 69 |
1 files changed, 44 insertions, 25 deletions
diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 8ee8e4e0a2b..918d2224085 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -932,31 +932,26 @@ static int throtl_select_dispatch(struct throtl_service_queue *parent_sq) return nr_disp; } +/** + * throtl_pending_timer_fn - timer function for service_queue->pending_timer + * @arg: the throtl_service_queue being serviced + * + * This timer is armed when a child throtl_grp with active bio's become + * pending and queued on the service_queue's pending_tree and expires when + * the first child throtl_grp should be dispatched. This function + * dispatches bio's from the children throtl_grps and kicks + * throtl_data->dispatch_work if there are bio's ready to be issued. + */ static void throtl_pending_timer_fn(unsigned long arg) { struct throtl_service_queue *sq = (void *)arg; struct throtl_data *td = sq_to_td(sq); - - queue_work(kthrotld_workqueue, &td->dispatch_work); -} - -/* work function to dispatch throttled bios */ -void blk_throtl_dispatch_work_fn(struct work_struct *work) -{ - struct throtl_data *td = container_of(work, struct throtl_data, - dispatch_work); - struct throtl_service_queue *sq = &td->service_queue; struct request_queue *q = td->queue; - struct bio_list bio_list_on_stack; - struct bio *bio; - struct blk_plug plug; bool dispatched = false; - int rw, ret; + int ret; spin_lock_irq(q->queue_lock); - bio_list_init(&bio_list_on_stack); - while (true) { throtl_log(sq, "dispatch nr_queued=%u read=%u write=%u", td->nr_queued[READ] + td->nr_queued[WRITE], @@ -964,10 +959,6 @@ void blk_throtl_dispatch_work_fn(struct work_struct *work) ret = throtl_select_dispatch(sq); if (ret) { - for (rw = READ; rw <= WRITE; rw++) { - bio_list_merge(&bio_list_on_stack, &sq->bio_lists[rw]); - bio_list_init(&sq->bio_lists[rw]); - } throtl_log(sq, "bios disp=%u", ret); dispatched = true; } @@ -981,13 +972,41 @@ void blk_throtl_dispatch_work_fn(struct work_struct *work) spin_lock_irq(q->queue_lock); } + if (dispatched) + queue_work(kthrotld_workqueue, &td->dispatch_work); + spin_unlock_irq(q->queue_lock); +} - /* - * If we dispatched some requests, unplug the queue to make sure - * immediate dispatch - */ - if (dispatched) { +/** + * blk_throtl_dispatch_work_fn - work function for throtl_data->dispatch_work + * @work: work item being executed + * + * This function is queued for execution when bio's reach the bio_lists[] + * of throtl_data->service_queue. Those bio's are ready and issued by this + * function. + */ +void blk_throtl_dispatch_work_fn(struct work_struct *work) +{ + struct throtl_data *td = container_of(work, struct throtl_data, + dispatch_work); + struct throtl_service_queue *td_sq = &td->service_queue; + struct request_queue *q = td->queue; + struct bio_list bio_list_on_stack; + struct bio *bio; + struct blk_plug plug; + int rw; + + bio_list_init(&bio_list_on_stack); + + spin_lock_irq(q->queue_lock); + for (rw = READ; rw <= WRITE; rw++) { + bio_list_merge(&bio_list_on_stack, &td_sq->bio_lists[rw]); + bio_list_init(&td_sq->bio_lists[rw]); + } + spin_unlock_irq(q->queue_lock); + + if (!bio_list_empty(&bio_list_on_stack)) { blk_start_plug(&plug); while((bio = bio_list_pop(&bio_list_on_stack))) generic_make_request(bio); |