From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755972Ab2LNDQA (ORCPT ); Thu, 13 Dec 2012 22:16:00 -0500 Received: from mail-pa0-f46.google.com ([209.85.220.46]:47660 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755708Ab2LNDP7 (ORCPT ); Thu, 13 Dec 2012 22:15:59 -0500 Date: Fri, 14 Dec 2012 11:15:51 +0800 From: Shaohua Li To: axboe@kernel.dk Cc: neilb@suse.de, linux-kernel@vger.kernel.org Subject: [patch 2/2]block: add plug for blkdev_issue_discard Message-ID: <20121214031551.GB30345@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Last post of this patch appears lost, so I resend this. Now discard merge works, add plug for blkdev_issue_discard. This will help discard request merge especially for raid0 case. In raid0, a big discard request is split to small requests, and if correct plug is added, such small requests can be merged in low layer. Signed-off-by: Shaohua Li --- block/blk-lib.c | 3 +++ 1 file changed, 3 insertions(+) Index: linux/block/blk-lib.c =================================================================== --- linux.orig/block/blk-lib.c 2012-12-14 10:03:22.305422686 +0800 +++ linux/block/blk-lib.c 2012-12-14 10:08:50.577295672 +0800 @@ -48,6 +48,7 @@ int blkdev_issue_discard(struct block_de struct bio_batch bb; struct bio *bio; int ret = 0; + struct blk_plug plug; if (!q) return -ENXIO; @@ -82,6 +83,7 @@ int blkdev_issue_discard(struct block_de bb.flags = 1 << BIO_UPTODATE; bb.wait = &wait; + blk_start_plug(&plug); while (nr_sects) { unsigned int req_sects; sector_t end_sect, tmp; @@ -120,6 +122,7 @@ int blkdev_issue_discard(struct block_de atomic_inc(&bb.done); submit_bio(type, bio); } + blk_finish_plug(&plug); /* Wait for bios in-flight */ if (!atomic_dec_and_test(&bb.done))