From ed8b752bccf2560e305e25125721d2f0ac759e88 Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Tue, 2 Aug 2011 12:32:08 +0100 Subject: dm table: set flush capability based on underlying devices DM has always advertised both REQ_FLUSH and REQ_FUA flush capabilities regardless of whether or not a given DM device's underlying devices also advertised a need for them. Block's flush-merge changes from 2.6.39 have proven to be more costly for DM devices. Performance regressions have been reported even when DM's underlying devices do not advertise that they have a write cache. Fix the performance regressions by configuring a DM device's flushing capabilities based on those of the underlying devices' capabilities. Signed-off-by: Mike Snitzer Signed-off-by: Alasdair G Kergon --- drivers/md/dm.c | 1 - 1 file changed, 1 deletion(-) (limited to 'drivers/md/dm.c') diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 1000eaf984ef..52b39f335bb3 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1808,7 +1808,6 @@ static void dm_init_md_queue(struct mapped_device *md) blk_queue_make_request(md->queue, dm_request); blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY); blk_queue_merge_bvec(md->queue, dm_merge_bvec); - blk_queue_flush(md->queue, REQ_FLUSH | REQ_FUA); } /* -- cgit v1.2.3