From 3154df262db52f1d27e01020e871f4345ec2f9a8 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Fri, 27 Sep 2019 15:24:31 +0800 Subject: 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 Cc: Hannes Reinecke Cc: Dave Chinner Reviewed-by: Damien Le Moal Signed-off-by: Ming Lei Signed-off-by: Jens Axboe --- block/blk-mq.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'block') 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; -- cgit