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authorMing Lei <ming.lei@redhat.com>2019-09-27 15:24:31 +0800
committerJens Axboe <axboe@kernel.dk>2019-09-27 11:40:21 -0600
commit3154df262db52f1d27e01020e871f4345ec2f9a8 (patch)
treec8cc0d818b1786463213c4a62d885ffaa47a1874 /block
parenta12de1d42d74ef3c80e9fb9a2da94daaef747869 (diff)
blk-mq: apply normal plugging for HDD
Some HDD drive may expose multiple hardware queues, such as MegraRaid. Let's apply the normal plugging for such devices because sequential IO may benefit a lot from plug merging. Cc: Bart Van Assche <bvanassche@acm.org> Cc: Hannes Reinecke <hare@suse.com> Cc: Dave Chinner <dchinner@redhat.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.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 5d4bef3c378d..ec791156e9cc 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1992,10 +1992,14 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
/* bypass scheduler for flush rq */
blk_insert_flush(rq);
blk_mq_run_hw_queue(data.hctx, true);
- } else if (plug && (q->nr_hw_queues == 1 || q->mq_ops->commit_rqs)) {
+ } else if (plug && (q->nr_hw_queues == 1 || q->mq_ops->commit_rqs ||
+ !blk_queue_nonrot(q))) {
/*
* Use plugging if we have a ->commit_rqs() hook as well, as
* we know the driver uses bd->last in a smart fashion.
+ *
+ * Use normal plugging if this disk is slow HDD, as sequential
+ * IO may benefit a lot from plug merging.
*/
unsigned int request_count = plug->rq_count;
struct request *last = NULL;