Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753324Ab0LNGcL (ORCPT ); Tue, 14 Dec 2010 01:32:11 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:59441 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751458Ab0LNGcJ (ORCPT ); Tue, 14 Dec 2010 01:32:09 -0500 Message-ID: <4D070F7C.3060503@cn.fujitsu.com> Date: Tue, 14 Dec 2010 14:32:28 +0800 From: Gui Jianfeng User-Agent: Thunderbird 2.0.0.24 (Windows/20100228) MIME-Version: 1.0 To: Jens Axboe , Vivek Goyal CC: linux kernel mailing list Subject: [PATCH] cfq-iosched: don't check cfqg in choose_service_tree() X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2010-12-14 14:32:04, Serialize by Router on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2010-12-14 14:32:04, Serialize complete at 2010-12-14 14:32:04 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1230 Lines: 36 When cfq_choose_cfqg() is called in select_queue(), there must be at least one backlogged CFQ queue waiting for dispatching, hence there must be at least one backlogged CFQ group on service tree. So we never call choose_service_tree() with cfqg == NULL. Signed-off-by: Gui Jianfeng --- block/cfq-iosched.c | 6 ------ 1 files changed, 0 insertions(+), 6 deletions(-) diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 9b186fd..c19d015 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -2103,12 +2103,6 @@ static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg) unsigned group_slice; enum wl_prio_t original_prio = cfqd->serving_prio; - if (!cfqg) { - cfqd->serving_prio = IDLE_WORKLOAD; - cfqd->workload_expires = jiffies + 1; - return; - } - /* Choose next priority. RT > BE > IDLE */ if (cfq_group_busy_queues_wl(RT_WORKLOAD, cfqd, cfqg)) cfqd->serving_prio = RT_WORKLOAD; -- 1.6.5.2 -- 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/