From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752643AbZIIDkR (ORCPT ); Tue, 8 Sep 2009 23:40:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751502AbZIIDkQ (ORCPT ); Tue, 8 Sep 2009 23:40:16 -0400 Received: from mx1.redhat.com ([209.132.183.28]:13569 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751445AbZIIDkQ (ORCPT ); Tue, 8 Sep 2009 23:40:16 -0400 Message-ID: <4AA72363.6000904@redhat.com> Date: Tue, 08 Sep 2009 23:39:15 -0400 From: Rik van Riel Organization: Red Hat, Inc User-Agent: Thunderbird 2.0.0.17 (X11/20080915) MIME-Version: 1.0 To: Vivek Goyal CC: linux-kernel@vger.kernel.org, jens.axboe@oracle.com, containers@lists.linux-foundation.org, dm-devel@redhat.com, nauman@google.com, dpshah@google.com, lizf@cn.fujitsu.com, mikew@google.com, fchecconi@gmail.com, paolo.valente@unimore.it, ryov@valinux.co.jp, fernando@oss.ntt.co.jp, s-uchida@ap.jp.nec.com, taka@valinux.co.jp, guijianfeng@cn.fujitsu.com, jmoyer@redhat.com, dhaval@linux.vnet.ibm.com, balbir@linux.vnet.ibm.com, righi.andrea@gmail.com, m-ikeda@ds.jp.nec.com, agk@redhat.com, akpm@linux-foundation.org, peterz@infradead.org, jmarchan@redhat.com, torvalds@linux-foundation.org, mingo@elte.hu Subject: Re: [PATCH 24/23] io-controller: Don't leave a queue active when a disk is idle References: <1251495072-7780-1-git-send-email-vgoyal@redhat.com> <20090908222821.GB3558@redhat.com> In-Reply-To: <20090908222821.GB3558@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Vivek Goyal wrote: > o It is possible that when there is only a single queue in the system, it > remains unexpired for a long time (because there is no IO activity on the > disk). So when next request comes in after a long time, it might make > scheduler think that all this while queue used the disk and it will assign > a high vdisktime to the queue. Hence make sure queue is expired once all > the requests have completed from the queue. > > o Also avoid unnecessarily expiring a queue when it has got one request > dispatched to the queue and waiting for it to finish and it does not have > more requests queued to dispatch. > > Signed-off-by: Vivek Goyal Acked-by: Rik van Riel -- All rights reversed.