From: Rik van Riel <riel@redhat.com>
Subject: Re: [PATCH 14/23] io-conroller: Prepare elevator layer
 for single queue schedulers
Date: Sun, 30 Aug 2009 22:49:08 -0400
Message-ID: <4A9B3A24.7050202@redhat.com>
References: <1251495072-7780-1-git-send-email-vgoyal@redhat.com>
	<1251495072-7780-15-git-send-email-vgoyal@redhat.com>
Reply-To: device-mapper development <dm-devel@redhat.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Return-path: <dm-devel-bounces@redhat.com>
In-Reply-To: <1251495072-7780-15-git-send-email-vgoyal@redhat.com>
List-Unsubscribe: <https://www.redhat.com/mailman/listinfo/dm-devel>,
	<mailto:dm-devel-request@redhat.com?subject=unsubscribe>
List-Archive: <https://www.redhat.com/archives/dm-devel>
List-Post: <mailto:dm-devel@redhat.com>
List-Help: <mailto:dm-devel-request@redhat.com?subject=help>
List-Subscribe: <https://www.redhat.com/mailman/listinfo/dm-devel>,
	<mailto:dm-devel-request@redhat.com?subject=subscribe>
Sender: dm-devel-bounces@redhat.com
Errors-To: dm-devel-bounces@redhat.com
To: Vivek Goyal <vgoyal@redhat.com>
Cc: dhaval@linux.vnet.ibm.com, peterz@infradead.org, dm-devel@redhat.com, dpshah@google.com, jens.axboe@oracle.com, agk@redhat.com, balbir@linux.vnet.ibm.com, paolo.valente@unimore.it, jmarchan@redhat.com, guijianfeng@cn.fujitsu.com, fernando@oss.ntt.co.jp, mikew@google.com, jmoyer@redhat.com, nauman@google.com, mingo@elte.hu, m-ikeda@ds.jp.nec.com, lizf@cn.fujitsu.com, fchecconi@gmail.com, s-uchida@ap.jp.nec.com, containers@lists.linux-foundation.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, righi.andrea@gmail.com, torvalds@linux-foundation.org
List-Id: dm-devel.ids

Vivek Goyal wrote:
> Elevator layer now has support for hierarchical fair queuing. cfq has
> been migrated to make use of it and now it is time to do groundwork for
> noop, deadline and AS.
> 
> noop deadline and AS don't maintain separate queues for different processes.
> There is only one single queue. Effectively one can think that in hierarchical
> setup, there will be one queue per cgroup where requests from all the
> processes in the cgroup will be queued.
> 
> Generally io scheduler takes care of creating queues. Because there is
> only one queue here, we have modified common layer to take care of queue
> creation and some other functionality. This special casing helps in keeping
> the changes to noop, deadline and AS to the minimum.
> 
> Signed-off-by: Nauman Rafique <nauman@google.com>
> Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
> Signed-off-by: Vivek Goyal <vgoyal@redhat.com>

Acked-by: Rik van Riel <riel@redhat.com>

-- 
All rights reversed.