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From: Mike Snitzer <snitzer@redhat.com>
To: dm-devel@redhat.com
Cc: axboe@kernel.dk, jmoyer@redhat.com
Subject: [PATCH 5/8] dm: don't schedule delayed run of the queue if nothing to do
Date: Tue,  3 Mar 2015 19:47:08 -0500	[thread overview]
Message-ID: <1425430031-78140-6-git-send-email-snitzer@redhat.com> (raw)
In-Reply-To: <1425430031-78140-1-git-send-email-snitzer@redhat.com>

In request-based DM's dm_request_fn(), if blk_peek_request() returns
NULL just return.  Avoids unnecessary blk_delay_queue().

Reported-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
---
 drivers/md/dm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 8e58df5..c13477a 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1960,7 +1960,7 @@ static void dm_request_fn(struct request_queue *q)
 	while (!blk_queue_stopped(q)) {
 		rq = blk_peek_request(q);
 		if (!rq)
-			goto delay_and_out;
+			goto out;
 
 		/* always use block 0 to find the target for flushes for now */
 		pos = 0;
-- 
1.9.3 (Apple Git-50)

  parent reply	other threads:[~2015-03-04  0:47 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-04  0:47 [PATCH 0/8] dm: optimize request-based queue processing Mike Snitzer
2015-03-04  0:47 ` [PATCH 1/8] dm: remove unnecessary wrapper around blk_lld_busy Mike Snitzer
2015-03-04  0:47 ` [PATCH 2/8] dm: remove request-based DM queue's lld_busy_fn hook Mike Snitzer
2015-03-04  0:47 ` [PATCH 3/8] dm: remove request-based logic from make_request_fn wrapper Mike Snitzer
2015-03-04  0:47 ` [PATCH 4/8] dm: only run the queue on completion if congested or no requests pending Mike Snitzer
2015-03-04  0:47 ` Mike Snitzer [this message]
2015-03-04  0:47 ` [PATCH 6/8] dm: don't start current request if it would've merged with the previous Mike Snitzer
2015-03-04  6:36   ` Hannes Reinecke
2015-03-04 17:26     ` Mike Snitzer
2015-03-09  1:04   ` Junichi Nomura
2015-03-09  3:30     ` Merla, ShivaKrishna
2015-03-09  6:09       ` Junichi Nomura
2015-03-09 16:10         ` Merla, ShivaKrishna
2015-03-10  1:05           ` Junichi Nomura
2015-03-10  1:59             ` Merla, ShivaKrishna
2015-03-10  5:43               ` Junichi Nomura
2015-03-04  0:47 ` [PATCH 7/8] dm sysfs: introduce ability to add writable attributes Mike Snitzer
2015-03-04  0:47 ` [PATCH 8/8] dm: impose configurable deadline for dm_request_fn's merge heuristic Mike Snitzer
2015-03-06 15:30   ` [PATCH 8/8 v2] " Mike Snitzer

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