Commit a31a9738 authored by Jens Axboe's avatar Jens Axboe
Browse files

block: don't use plugging on SSD devices 



We just want to hand the first bits of IO to the device as fast
as possible. Gains a few percent on the IOPS rate.

Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent a185eb4b

block/blk-core.c

+3 −4
Original line number Diff line number Diff line
@@ -268,8 +268,7 @@ void __generic_unplug_device(struct request_queue *q) 
{

	if (unlikely(blk_queue_stopped(q)))

		return;



	if (!blk_remove_plug(q))

	if (!blk_remove_plug(q) && !blk_queue_nonrot(q))

		return;



	q->request_fn(q);
@@ -1241,11 +1240,11 @@ 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 (elv_queue_empty(q))

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

		blk_plug_device(q);

	add_request(q, req);

out:

	if (sync)

	if (sync || blk_queue_nonrot(q))

		__generic_unplug_device(q);

	spin_unlock_irq(q->queue_lock);

	return 0;