Commit 644b2d99 authored by Jens Axboe's avatar Jens Axboe Committed by Linus Torvalds
Browse files

block: enabling plugging on SSD devices that don't do queuing 



For the older SSD devices that don't do command queuing, we do want to
enable plugging to get better merging.

Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4194b1ea

block/blk-core.c

+11 −2
Original line number Diff line number Diff line
@@ -1136,6 +1136,15 @@ void init_request_from_bio(struct request *req, struct bio *bio) 
	blk_rq_bio_prep(req->q, req, bio);

}



/*

 * Only disabling plugging for non-rotational devices if it does tagging

 * as well, otherwise we do need the proper merging

 */

static inline bool queue_should_plug(struct request_queue *q)

{

	return !(blk_queue_nonrot(q) && blk_queue_tagged(q));

}



static int __make_request(struct request_queue *q, struct bio *bio)

{

	struct request *req;
@@ -1242,11 +1251,11 @@ static int __make_request(struct request_queue *q, struct bio *bio) 
	if (test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags) ||

	    bio_flagged(bio, BIO_CPU_AFFINE))

		req->cpu = blk_cpu_to_group(smp_processor_id());

	if (!blk_queue_nonrot(q) && elv_queue_empty(q))

	if (queue_should_plug(q) && elv_queue_empty(q))

		blk_plug_device(q);

	add_request(q, req);

out:

	if (unplug || blk_queue_nonrot(q))

	if (unplug || !queue_should_plug(q))

		__generic_unplug_device(q);

	spin_unlock_irq(q->queue_lock);

	return 0;