Commit e70c301f authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

block: don't reorder requests in blk_add_rq_to_plug 



Add requests to the tail of the list instead of the front so that they
are queued up in submission order.

Remove the re-reordering in blk_mq_dispatch_plug_list, virtio_queue_rqs
and nvme_queue_rqs now that the list is ordered as expected.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20241113152050.157179-6-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent a3396b99

block/blk-mq.c

+2 −2
Original line number Diff line number Diff line
@@ -1392,7 +1392,7 @@ static void blk_add_rq_to_plug(struct blk_plug *plug, struct request *rq) 
	 */

	if (!plug->has_elevator && (rq->rq_flags & RQF_SCHED_TAGS))

		plug->has_elevator = true;

	rq_list_add_head(&plug->mq_list, rq);

	rq_list_add_tail(&plug->mq_list, rq);

	plug->rq_count++;

}
@@ -2844,7 +2844,7 @@ static void blk_mq_dispatch_plug_list(struct blk_plug *plug, bool from_sched) 
			rq_list_add_tail(&requeue_list, rq);

			continue;

		}

		list_add(&rq->queuelist, &list);

		list_add_tail(&rq->queuelist, &list);

		depth++;

	} while (!rq_list_empty(&plug->mq_list));

drivers/block/virtio_blk.c

+1 −1
Original line number Diff line number Diff line
@@ -514,7 +514,7 @@ static void virtio_queue_rqs(struct rq_list *rqlist) 
		vq = this_vq;



		if (virtblk_prep_rq_batch(req))

			rq_list_add_head(&submit_list, req); /* reverse order */

			rq_list_add_tail(&submit_list, req);

		else

			rq_list_add_tail(&requeue_list, req);

	}

drivers/nvme/host/pci.c

+1 −1
Original line number Diff line number Diff line
@@ -945,7 +945,7 @@ static void nvme_queue_rqs(struct rq_list *rqlist) 
		nvmeq = req->mq_hctx->driver_data;



		if (nvme_prep_rq_batch(nvmeq, req))

			rq_list_add_head(&submit_list, req); /* reverse order */

			rq_list_add_tail(&submit_list, req);

		else

			rq_list_add_tail(&requeue_list, req);

	}