Commit 0effb390 authored by Bart Van Assche's avatar Bart Van Assche Committed by Jens Axboe
Browse files

block: mq-deadline: Handle requeued requests correctly 



Start dispatching from the start of a zone instead of from the starting
position of the most recently dispatched request.

If a zoned write is requeued with an LBA that is lower than already
inserted zoned writes, make sure that it is submitted first.

Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
Cc: Damien Le Moal <dlemoal@kernel.org>
Cc: Ming Lei <ming.lei@redhat.com>
Signed-off-by: default avatarBart Van Assche <bvanassche@acm.org>
Reviewed-by: default avatarDamien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20230517174230.897144-11-bvanassche@acm.org


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 83c46ed6

block/mq-deadline.c

+32 −2
Original line number Diff line number Diff line
@@ -156,13 +156,28 @@ deadline_latter_request(struct request *rq) 
	return NULL;

}



/* Return the first request for which blk_rq_pos() >= pos. */

/*

 * Return the first request for which blk_rq_pos() >= @pos. For zoned devices,

 * return the first request after the start of the zone containing @pos.

 */

static inline struct request *deadline_from_pos(struct dd_per_prio *per_prio,

				enum dd_data_dir data_dir, sector_t pos)

{

	struct rb_node *node = per_prio->sort_list[data_dir].rb_node;

	struct request *rq, *res = NULL;



	if (!node)

		return NULL;



	rq = rb_entry_rq(node);

	/*

	 * A zoned write may have been requeued with a starting position that

	 * is below that of the most recently dispatched request. Hence, for

	 * zoned writes, start searching from the start of a zone.

	 */

	if (blk_rq_is_seq_zoned_write(rq))

		pos -= round_down(pos, rq->q->limits.chunk_sectors);



	while (node) {

		rq = rb_entry_rq(node);

		if (blk_rq_pos(rq) >= pos) {
@@ -806,6 +821,8 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq, 
		list_add(&rq->queuelist, &per_prio->dispatch);

		rq->fifo_time = jiffies;

	} else {

		struct list_head *insert_before;



		deadline_add_rq_rb(per_prio, rq);



		if (rq_mergeable(rq)) {
@@ -818,7 +835,20 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq, 
		 * set expire time and add to fifo list

		 */

		rq->fifo_time = jiffies + dd->fifo_expire[data_dir];

		list_add_tail(&rq->queuelist, &per_prio->fifo_list[data_dir]);

		insert_before = &per_prio->fifo_list[data_dir];

#ifdef CONFIG_BLK_DEV_ZONED

		/*

		 * Insert zoned writes such that requests are sorted by

		 * position per zone.

		 */

		if (blk_rq_is_seq_zoned_write(rq)) {

			struct request *rq2 = deadline_latter_request(rq);



			if (rq2 && blk_rq_zone_no(rq2) == blk_rq_zone_no(rq))

				insert_before = &rq2->queuelist;

		}

#endif

		list_add_tail(&rq->queuelist, insert_before);

	}

}