diff options
| author | Ming Lei <ming.lei@redhat.com> | 2019-09-27 15:24:30 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2019-09-27 11:38:28 -0600 |
| commit | a12de1d42d74ef3c80e9fb9a2da94daaef747869 (patch) | |
| tree | 730e2f9be02fa7087af02e7b9d825dc7a3b2b3b0 /block | |
| parent | 8d6996630c03d7ceeabe2611378fea5ca1c3f1b3 (diff) | |
blk-mq: honor IO scheduler for multiqueue devices
If a device is using multiple queues, the IO scheduler may be bypassed.
This may hurt performance for some slow MQ devices, and it also breaks
zoned devices which depend on mq-deadline for respecting the write order
in one zone.
Don't bypass io scheduler if we have one setup.
This patch can double sequential write performance basically on MQ
scsi_debug when mq-deadline is applied.
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Javier González <javier@javigon.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-mq.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c index 6e3b15f70cd7..5d4bef3c378d 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2012,6 +2012,8 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) } blk_add_rq_to_plug(plug, rq); + } else if (q->elevator) { + blk_mq_sched_insert_request(rq, false, true, true); } else if (plug && !blk_queue_nomerges(q)) { /* * We do limited plugging. If the bio can be merged, do that. @@ -2035,8 +2037,8 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) blk_mq_try_issue_directly(data.hctx, same_queue_rq, &cookie); } - } else if ((q->nr_hw_queues > 1 && is_sync) || (!q->elevator && - !data.hctx->dispatch_busy)) { + } else if ((q->nr_hw_queues > 1 && is_sync) || + !data.hctx->dispatch_busy) { blk_mq_try_issue_directly(data.hctx, rq, &cookie); } else { blk_mq_sched_insert_request(rq, false, true, true); |