From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756164AbYKDXXy (ORCPT ); Tue, 4 Nov 2008 18:23:54 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754049AbYKDXXq (ORCPT ); Tue, 4 Nov 2008 18:23:46 -0500 Received: from gw.goop.org ([64.81.55.164]:43095 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752286AbYKDXXp (ORCPT ); Tue, 4 Nov 2008 18:23:45 -0500 Message-ID: <4910D97E.2030203@goop.org> Date: Tue, 04 Nov 2008 15:23:42 -0800 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.17 (X11/20081009) MIME-Version: 1.0 To: Jens Axboe CC: =?ISO-8859-1?Q?Fernando_Luis_V=E1zquez_Cao?= , rusty@rustcorp.com.au, linux-kernel@vger.kernel.org, jeremy@xensource.com Subject: Re: [PATCH 1/3] block: add queue flag for paravirt frontend drivers References: <1219754894.7235.44.camel@sebastian.kern.oss.ntt.co.jp> <20080826143900.GM20055@kernel.dk> <1219814047.18991.52.camel@sebastian.kern.oss.ntt.co.jp> <1225100686.7370.79.camel@sebastian.kern.oss.ntt.co.jp> <20081027125624.GA22217@kernel.dk> In-Reply-To: <20081027125624.GA22217@kernel.dk> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jens Axboe wrote: > On Mon, Oct 27 2008, Fernando Luis Vázquez Cao wrote: > >> As is the case with SSD devices, we do not want to idle in AS/CFQ when >> the block device is a paravirt front-end driver. This patch adds a flag >> (QUEUE_FLAG_VIRT) which should be used by front-end drivers such as >> virtio_blk and xen-blkfront to indicate a paravirtualized device. >> > > All three patches look fine, although we could just reuse > QUEUE_FLAG_NONROT directly. But I agree it makes sense to make the > distinction, so I've just applied 1-3. > I guess in theory you could imagine that the virtual device is mapped directly onto a physical device, and the host OS does no scheduling, in which case it would be appropriate for the guest do the work. But I think otherwise this makes sense. J