block: improve logic around when to sort a plug list (ce5b009c) · Commits · 戴 / test

block/blk-core.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -1780,6 +1780,7 @@ void blk_start_plug(struct blk_plug *plug)
		INIT_LIST_HEAD(&plug->mq_list);
		INIT_LIST_HEAD(&plug->cb_list);
		plug->rq_count = 0;
		plug->multiple_queues = false;

		/*
		* Store ordering should not be needed here, since a potential

+18 −5

Original line number	Diff line number	Diff line
		@@ -1677,6 +1677,7 @@ void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
		list_splice_init(&plug->mq_list, &list);
		plug->rq_count = 0;

		if (plug->rq_count > 2 && plug->multiple_queues)
		list_sort(NULL, &list, plug_rq_cmp);

		this_q = NULL;
		@@ -1866,6 +1867,20 @@ void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
		}
		}

		static void blk_add_rq_to_plug(struct blk_plug plug, struct request rq)
		{
		list_add_tail(&rq->queuelist, &plug->mq_list);
		plug->rq_count++;
		if (!plug->multiple_queues && !list_is_singular(&plug->mq_list)) {
		struct request *tmp;

		tmp = list_first_entry(&plug->mq_list, struct request,
		queuelist);
		if (tmp->q != rq->q)
		plug->multiple_queues = true;
		}
		}

		static blk_qc_t blk_mq_make_request(struct request_queue q, struct bio bio)
		{
		const int is_sync = op_is_sync(bio->bi_opf);
		@@ -1932,8 +1947,7 @@ static blk_qc_t blk_mq_make_request(struct request_queue q, struct bio bio)
		trace_block_plug(q);
		}

		list_add_tail(&rq->queuelist, &plug->mq_list);
		plug->rq_count++;
		blk_add_rq_to_plug(plug, rq);
		} else if (plug && !blk_queue_nomerges(q)) {
		blk_mq_bio_to_request(rq, bio);

		@@ -1950,8 +1964,7 @@ static blk_qc_t blk_mq_make_request(struct request_queue q, struct bio bio)
		list_del_init(&same_queue_rq->queuelist);
		plug->rq_count--;
		}
		list_add_tail(&rq->queuelist, &plug->mq_list);
		plug->rq_count++;
		blk_add_rq_to_plug(plug, rq);

		blk_mq_put_ctx(data.ctx);

+1 −0

Original line number	Diff line number	Diff line
		@@ -1131,6 +1131,7 @@ struct blk_plug {
		struct list_head mq_list; /* blk-mq requests */
		struct list_head cb_list; /* md requires an unplug callback */
		unsigned short rq_count;
		bool multiple_queues;
		};
		#define BLK_MAX_REQUEST_COUNT 16
		#define BLK_PLUG_FLUSH_SIZE (128 * 1024)