Commit 4cafe86c authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
Browse files

blk-mq: run dispatch lock once in case of issuing from list 



It isn't necessary to call blk_mq_run_dispatch_ops() once for issuing
single request directly, and enough to do it one time when issuing from
whole list.

Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211203131534.3668411-5-ming.lei@redhat.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent bcc330f4

block/blk-mq-sched.c

+2 −1
Original line number Diff line number Diff line
@@ -475,7 +475,8 @@ void blk_mq_sched_insert_requests(struct blk_mq_hw_ctx *hctx, 
		 * us one extra enqueue & dequeue to sw queue.

		 */

		if (!hctx->dispatch_busy && !run_queue_async) {

			blk_mq_try_issue_list_directly(hctx, list);

			blk_mq_run_dispatch_ops(hctx->queue,

				blk_mq_try_issue_list_directly(hctx, list));

			if (list_empty(list))

				goto out;

		}

block/blk-mq.c

+6 −8
Original line number Diff line number Diff line
@@ -2464,12 +2464,7 @@ static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, 


static blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last)

{

	blk_status_t ret;

	struct blk_mq_hw_ctx *hctx = rq->mq_hctx;



	blk_mq_run_dispatch_ops(rq->q,

		ret = __blk_mq_try_issue_directly(hctx, rq, true, last));

	return ret;

	return __blk_mq_try_issue_directly(rq->mq_hctx, rq, true, last);

}



static void blk_mq_plug_issue_direct(struct blk_plug *plug, bool from_schedule)
@@ -2526,7 +2521,8 @@ void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule) 
	plug->rq_count = 0;



	if (!plug->multiple_queues && !plug->has_elevator && !from_schedule) {

		blk_mq_plug_issue_direct(plug, false);

		blk_mq_run_dispatch_ops(plug->mq_list->q,

				blk_mq_plug_issue_direct(plug, false));

		if (rq_list_empty(plug->mq_list))

			return;

	}
@@ -2867,7 +2863,9 @@ blk_status_t blk_insert_cloned_request(struct request_queue *q, struct request * 
	 * bypass a potential scheduler on the bottom device for

	 * insert.

	 */

	return blk_mq_request_issue_directly(rq, true);

	blk_mq_run_dispatch_ops(rq->q,

			ret = blk_mq_request_issue_directly(rq, true));

	return ret;

}

EXPORT_SYMBOL_GPL(blk_insert_cloned_request);