Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753800AbZLHHrx (ORCPT ); Tue, 8 Dec 2009 02:47:53 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752645AbZLHHrv (ORCPT ); Tue, 8 Dec 2009 02:47:51 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:51348 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751591AbZLHHrv (ORCPT ); Tue, 8 Dec 2009 02:47:51 -0500 Message-ID: <4B1E03AD.7060606@cn.fujitsu.com> Date: Tue, 08 Dec 2009 15:43:41 +0800 From: Gui Jianfeng User-Agent: Thunderbird 2.0.0.23 (Windows/20090812) MIME-Version: 1.0 To: Vivek Goyal , Jens Axboe CC: linux-kernel@vger.kernel.org Subject: [PATCH] cfq: Optimization for close cooperating queue searching Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1102 Lines: 33 It doesn't make any sense to try to find out a close cooperating queue if current cfqq is the only one in the group. Signed-off-by: Gui Jianfeng --- block/cfq-iosched.c | 6 ++++++ 1 files changed, 6 insertions(+), 0 deletions(-) diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index cfb0b2f..89b5dd9 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -1750,6 +1750,12 @@ static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd, return NULL; /* + * Don't search priority tree if it's the only queue in the group. + */ + if (cur_cfqq->cfqg->nr_cfqq == 1) + return NULL; + + /* * We should notice if some of the queues are cooperating, eg * working closely on the same area of the disk. In that case, * we can group them together and don't waste time idling. -- 1.5.4.rc3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/