Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753262AbYJ2JZU (ORCPT ); Wed, 29 Oct 2008 05:25:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753029AbYJ2JZI (ORCPT ); Wed, 29 Oct 2008 05:25:08 -0400 Received: from gw.goop.org ([64.81.55.164]:49812 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752814AbYJ2JZH (ORCPT ); Wed, 29 Oct 2008 05:25:07 -0400 Message-ID: <49082BBC.60302@goop.org> Date: Wed, 29 Oct 2008 20:24:12 +1100 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.17 (X11/20081009) MIME-Version: 1.0 To: Ingo Molnar CC: FUJITA Tomonori , jens.axboe@oracle.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] x86: replace BIO_VMERGE_BOUNDARY with BIOVEC_PHYS_MERGEABLE References: <20081027094111.GU22217@kernel.dk> <4905A961.9000603@goop.org> <20081027115659.GZ22217@kernel.dk> <20081029080603J.fujita.tomonori@lab.ntt.co.jp> <20081029083713.GE6364@elte.hu> In-Reply-To: <20081029083713.GE6364@elte.hu> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1756 Lines: 51 Ingo Molnar wrote: > * FUJITA Tomonori wrote: > > >> On Mon, 27 Oct 2008 12:57:00 +0100 >> Jens Axboe wrote: >> >> >>> On Mon, Oct 27 2008, Jeremy Fitzhardinge wrote: >>> >>>> Jens Axboe wrote: >>>> >>>>> Pretty much baffles me as well, xen should just need to do >>>>> >>>>> #define BIOVEC_PHYS_MERGEABLE(vec1, vec2) 0 >>>>> >>>>> >>>> It needs to be a runtime switch, since we only want to do this when >>>> actually running under Xen. Also, its possible that the two pages might >>>> actually be physically contiguous, so they could be merged anyway. >>>> >>> Alright, then add a xen_biovec_phys_mergeable(vec1, vec2) in the xen >>> code that actually checks this for real. You can add your switch there >>> as well. Then put the BIOVEC_PHYS_MERGEABLE() in the xen arch includes, >>> done. >>> >>> What Tomo is saying is that this has nothing to do with virtual merging, >>> and he's right. >>> >> Yeah, overriding BIOVEC_PHYS_MERGEABLE perfectly works for Xen. And it >> is not related with BIO_VMERGE_BOUNDARY at all. >> >> Ingo, please put this patch into your tree: >> >> http://marc.info/?l=linux-kernel&m=122482703716620&w=2 >> > > does it have any dependency on: > > Subject: [PATCH 1/2] bio: define __BIOVEC_PHYS_MERGEABLE > No, they're independent. Defining __BIOVEC_PHYS_MERGEABLE will be useful for the Xen changes I need to make in the wake of Tomo's patch. J -- 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/