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authorJens Axboe <jens.axboe@oracle.com>2009-04-06 14:48:06 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2009-04-06 08:04:54 -0700
commit644b2d99b7a8677a56909a7b1fde31677eba4471 (patch)
tree5271613f4fd9e6fbf11c16aff8dec8f1946b2234 /block
parent4194b1eaf18ddc3eee9597e8800b6d2ffdfd3614 (diff)
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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 <jens.axboe@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'block')
-rw-r--r--block/blk-core.c13
1 files changed, 11 insertions, 2 deletions
diff --git a/block/blk-core.c b/block/blk-core.c
index a32b571aaaa..c4198f083e5 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;