From 651930bc1c2a2550fde93a8cfa1a201c363a0ca1 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 14 May 2013 13:52:35 -0700 Subject: blk-throttle: dispatch to throtl_data->service_queue.bio_lists[] throtl_service_queues will eventually form a tree which is anchored at throtl_data->service_queue and queue bios will climb the tree to the top service_queue to be executed. This patch makes the dispatch paths in blk_throtl_dispatch_work_fn() and blk_throtl_drain() to dispatch bios to throtl_data->service_queue.bio_lists[] instead of the on-stack bio_lists. This will keep the final dispatch to the top level service_queue share the same mechanism as dispatches through the rest of the hierarchy. As bio's should be issued in a sleepable context, blk_throtl_dispatch_work_fn() transfers all dispatched bio's from the service_queue bio_lists[] into an onstack one before dropping queue_lock and issuing the bio's. Signed-off-by: Tejun Heo Acked-by: Vivek Goyal --- block/blk-throttle.c | 40 +++++++++++++++++++++++----------------- 1 file changed, 23 insertions(+), 17 deletions(-) (limited to 'block/blk-throttle.c') diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 6f57f94c3c5..154bd63719c 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -743,7 +743,7 @@ static void tg_update_disptime(struct throtl_grp *tg, } static void tg_dispatch_one_bio(struct throtl_grp *tg, bool rw, - struct bio_list *bl) + struct throtl_service_queue *parent_sq) { struct throtl_service_queue *sq = &tg->service_queue; struct bio *bio; @@ -757,13 +757,14 @@ static void tg_dispatch_one_bio(struct throtl_grp *tg, bool rw, tg->td->nr_queued[rw]--; throtl_charge_bio(tg, bio); - bio_list_add(bl, bio); + bio_list_add(&parent_sq->bio_lists[rw], bio); bio->bi_rw |= REQ_THROTTLED; throtl_trim_slice(tg, rw); } -static int throtl_dispatch_tg(struct throtl_grp *tg, struct bio_list *bl) +static int throtl_dispatch_tg(struct throtl_grp *tg, + struct throtl_service_queue *parent_sq) { struct throtl_service_queue *sq = &tg->service_queue; unsigned int nr_reads = 0, nr_writes = 0; @@ -776,7 +777,7 @@ static int throtl_dispatch_tg(struct throtl_grp *tg, struct bio_list *bl) while ((bio = bio_list_peek(&sq->bio_lists[READ])) && tg_may_dispatch(tg, bio, NULL)) { - tg_dispatch_one_bio(tg, bio_data_dir(bio), bl); + tg_dispatch_one_bio(tg, bio_data_dir(bio), parent_sq); nr_reads++; if (nr_reads >= max_nr_reads) @@ -786,7 +787,7 @@ static int throtl_dispatch_tg(struct throtl_grp *tg, struct bio_list *bl) while ((bio = bio_list_peek(&sq->bio_lists[WRITE])) && tg_may_dispatch(tg, bio, NULL)) { - tg_dispatch_one_bio(tg, bio_data_dir(bio), bl); + tg_dispatch_one_bio(tg, bio_data_dir(bio), parent_sq); nr_writes++; if (nr_writes >= max_nr_writes) @@ -796,8 +797,7 @@ static int throtl_dispatch_tg(struct throtl_grp *tg, struct bio_list *bl) return nr_reads + nr_writes; } -static int throtl_select_dispatch(struct throtl_service_queue *parent_sq, - struct bio_list *bl) +static int throtl_select_dispatch(struct throtl_service_queue *parent_sq) { unsigned int nr_disp = 0; @@ -813,7 +813,7 @@ static int throtl_select_dispatch(struct throtl_service_queue *parent_sq, throtl_dequeue_tg(tg, parent_sq); - nr_disp += throtl_dispatch_tg(tg, bl); + nr_disp += throtl_dispatch_tg(tg, parent_sq); if (sq->nr_queued[0] || sq->nr_queued[1]) tg_update_disptime(tg, parent_sq); @@ -830,11 +830,13 @@ void blk_throtl_dispatch_work_fn(struct work_struct *work) { struct throtl_data *td = container_of(to_delayed_work(work), struct throtl_data, dispatch_work); + struct throtl_service_queue *sq = &td->service_queue; struct request_queue *q = td->queue; unsigned int nr_disp = 0; struct bio_list bio_list_on_stack; struct bio *bio; struct blk_plug plug; + int rw; spin_lock_irq(q->queue_lock); @@ -844,10 +846,15 @@ void blk_throtl_dispatch_work_fn(struct work_struct *work) td->nr_queued[READ] + td->nr_queued[WRITE], td->nr_queued[READ], td->nr_queued[WRITE]); - nr_disp = throtl_select_dispatch(&td->service_queue, &bio_list_on_stack); + nr_disp = throtl_select_dispatch(sq); - if (nr_disp) + if (nr_disp) { + 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(td, "bios disp=%u", nr_disp); + } throtl_schedule_next_dispatch(td); @@ -1156,27 +1163,26 @@ void blk_throtl_drain(struct request_queue *q) struct throtl_data *td = q->td; struct throtl_service_queue *parent_sq = &td->service_queue; struct throtl_grp *tg; - struct bio_list bl; struct bio *bio; + int rw; queue_lockdep_assert_held(q); - bio_list_init(&bl); - while ((tg = throtl_rb_first(parent_sq))) { struct throtl_service_queue *sq = &tg->service_queue; throtl_dequeue_tg(tg, parent_sq); while ((bio = bio_list_peek(&sq->bio_lists[READ]))) - tg_dispatch_one_bio(tg, bio_data_dir(bio), &bl); + tg_dispatch_one_bio(tg, bio_data_dir(bio), parent_sq); while ((bio = bio_list_peek(&sq->bio_lists[WRITE]))) - tg_dispatch_one_bio(tg, bio_data_dir(bio), &bl); + tg_dispatch_one_bio(tg, bio_data_dir(bio), parent_sq); } spin_unlock_irq(q->queue_lock); - while ((bio = bio_list_pop(&bl))) - generic_make_request(bio); + for (rw = READ; rw <= WRITE; rw++) + while ((bio = bio_list_pop(&parent_sq->bio_lists[rw]))) + generic_make_request(bio); spin_lock_irq(q->queue_lock); } -- cgit v1.2.3-70-g09d2