Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753033AbaBXPIv (ORCPT ); Mon, 24 Feb 2014 10:08:51 -0500 Received: from smtp02.citrix.com ([66.165.176.63]:55556 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752868AbaBXPIt (ORCPT ); Mon, 24 Feb 2014 10:08:49 -0500 X-IronPort-AV: E=Sophos;i="4.97,535,1389744000"; d="scan'208";a="103557346" Message-ID: <530B606F.2070902@citrix.com> Date: Mon, 24 Feb 2014 15:08:31 +0000 From: Zoltan Kiss User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 MIME-Version: 1.0 To: Zoltan Kiss , Ian Campbell CC: , , , , Subject: Re: [PATCH net-next v5 4/9] xen-netback: Change RX path for mapped SKB fragments References: <1390253069-25507-1-git-send-email-zoltan.kiss@citrix.com> <1390253069-25507-5-git-send-email-zoltan.kiss@citrix.com> <1392745532.23084.65.camel@kazak.uk.xensource.com> <53093051.9040907@citrix.com> <530B4E05.4020900@schaman.hu> In-Reply-To: <530B4E05.4020900@schaman.hu> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.68.14.50] X-DLP: MIA1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 24/02/14 13:49, Zoltan Kiss wrote: > On 22/02/14 23:18, Zoltan Kiss wrote: >> On 18/02/14 17:45, Ian Campbell wrote: >>> On Mon, 2014-01-20 at 21:24 +0000, Zoltan Kiss wrote: >>> >>> Re the Subject: change how? Perhaps "handle foreign mapped pages on the >>> guest RX path" would be clearer. >> Ok, I'll do that. >> >>> >>>> RX path need to know if the SKB fragments are stored on pages from >>>> another >>>> domain. >>> Does this not need to be done either before the mapping change or at >>> the >>> same time? -- otherwise you have a window of a couple of commits where >>> things are broken, breaking bisectability. >> I can move this to the beginning, to keep bisectability. I've put it >> here originally because none of these makes sense without the >> previous patches. > Well, I gave it a close look: to move this to the beginning as a > separate patch I would need to put move a lot of definitions from the > first patch to here (ubuf_to_vif helper, xenvif_zerocopy_callback > etc.). That would be the best from bisect point of view, but from > patch review point of view even worse than now. So the only option I > see is to merge this with the first 2 patches, so it will be even bigger. Actually I was stupid, we can move this patch earlier and introduce stubs for those 2 functions. But for the another two patches (#6 and #8) it's still true that we can't move them before, only merge them into the main, as they heavily rely on the main patch. #6 is necessary for Windows frontends, as they are keen to send too many slots. #8 is quite a rare case, happens only if a guest wedge or malicious, and sits on the packet. So my question is still up: do you prefer perfect bisectability or more segmented patches which are not that pain to review? > And based on that principle, patch #6 and #8 should be merged there as > well, as they solve corner cases introduced by the grant mapping. > I don't know how much the bisecting requirements are written in stone. > At this moment, all the separate patches compile, but after #2 there > are new problems solved in #4, #6 and #8. If someone bisect in the > middle of this range and run into these problems, they could quite > easily figure out what went wrong looking at the adjacent patches. So > I would recommend to keep this current order. > What's your opinion? > > Zoli -- 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/