From 644b2d99b7a8677a56909a7b1fde31677eba4471 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Mon, 6 Apr 2009 14:48:06 +0200 Subject: 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: Jens Axboe Signed-off-by: Linus Torvalds --- block/blk-core.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) (limited to 'block') diff --git a/block/blk-core.c b/block/blk-core.c index a32b571aaaa2..c4198f083e5b 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -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 @@ get_rq: 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; -- cgit v1.2.2