Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754833AbYHPHNw (ORCPT ); Sat, 16 Aug 2008 03:13:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752543AbYHPHNn (ORCPT ); Sat, 16 Aug 2008 03:13:43 -0400 Received: from ozlabs.org ([203.10.76.45]:35824 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752504AbYHPHNn convert rfc822-to-8bit (ORCPT ); Sat, 16 Aug 2008 03:13:43 -0400 From: Rusty Russell To: Fernando Luis =?utf-8?q?V=C3=A1zquez_Cao?= Subject: Re: request->ioprio Date: Sat, 16 Aug 2008 17:13:36 +1000 User-Agent: KMail/1.9.9 Cc: Jens Axboe , linux-kernel@vger.kernel.org, =?utf-8?q?=E5=90=89=E5=B7=9D_=E6=8B=93=E5=93=89?= , dpshah@google.com References: <1218014196.4419.44.camel@sebastian.kern.oss.ntt.co.jp> <200808141216.33688.rusty@rustcorp.com.au> <1218779462.5291.59.camel@sebastian.kern.oss.ntt.co.jp> In-Reply-To: <1218779462.5291.59.camel@sebastian.kern.oss.ntt.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8BIT Content-Disposition: inline Message-Id: <200808161713.37146.rusty@rustcorp.com.au> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1259 Lines: 27 On Friday 15 August 2008 15:51:02 Fernando Luis Vázquez Cao wrote: > On Thu, 2008-08-14 at 12:16 +1000, Rusty Russell wrote: > > On Wednesday 13 August 2008 17:06:03 Fernando Luis Vázquez Cao wrote: > > > Besides, I guess that accessing the io context information (such as > > > ioprio) of a request through elevator-specific private structures is > > > not something we want virtio_blk (or future users) to do. > > > > The only semantic I assumed was "higher is better". The server (ie. > > host) can really only use the information to schedule between I/Os for > > that particular guest anyway. > > Does that mean you are not going to incorporate the prio class system > that is used in Linux? Actually, since it's unused at the moment, we can define it however we want. But note that this is an ABI; while the kernel-internal definitions are fluid, this semantic must stay the same (even if the actual values differ). So we should probably put an explicit mapping function there anyway. Thanks, Rusty. -- 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/