From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ryo Tsuruta Subject: Re: IO scheduler based IO Controller V2 Date: Thu, 07 May 2009 09:18:58 +0900 (JST) Message-ID: <20090507.091858.226775723.ryov__27289.7611409009$1241656006$gmane$org@valinux.co.jp> References: <1241553525-28095-1-git-send-email-vgoyal@redhat.com> <20090505132441.1705bfad.akpm@linux-foundation.org> <20090506023332.GA1212@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20090506023332.GA1212-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: vgoyal-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org Cc: dhaval-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org, snitzer-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, dm-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, jens.axboe-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org, agk-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, balbir-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org, paolo.valente-rcYM44yAMweonA0d6jMUrA@public.gmane.org, fernando-gVGce1chcLdL9jVzuh4AOg@public.gmane.org, jmoyer-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, fchecconi-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, righi.andrea-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org List-Id: containers.vger.kernel.org Hi Vivek, > Ryo, dm-ioband breaks the notion of classes and priority of CFQ because > of FIFO dispatch of buffered bios. Apart from that it tries to provide > fairness in terms of actual IO done and that would mean a seeky workload > will can use disk for much longer to get equivalent IO done and slow down > other applications. Implementing IO controller at IO scheduler level gives > us tigher control. Will it not meet your requirements? If you got specific > concerns with IO scheduler based contol patches, please highlight these and > we will see how these can be addressed. I'd like to avoid making complicated existing IO schedulers and other kernel codes and to give a choice to users whether or not to use it. I know that you chose an approach that using compile time options to get the same behavior as old system, but device-mapper drivers can be added, removed and replaced while system is running. Thanks, Ryo Tsuruta