Date: Thu, 27 Feb 2014 16:01:41 +0000
From: Wei Liu <wei.liu2@citrix.com>
To: Zoltan Kiss <zoltan.kiss@citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>, Ian Campbell <Ian.Campbell@citrix.com>,
        <xen-devel@lists.xenproject.org>, <netdev@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <jonathan.davies@citrix.com>
Subject: Re: [PATCH net-next v5 4/9] xen-netback: Change RX path for mapped
 SKB fragments
Message-ID: <20140227160141.GJ16241@zion.uk.xensource.com>
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>
 <530B606F.2070902@citrix.com>
 <20140227124327.GD16241@zion.uk.xensource.com>
 <530F5E9B.5020404@citrix.com>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Disposition: inline
In-Reply-To: <530F5E9B.5020404@citrix.com>
User-Agent: Mutt/1.5.21 (2010-09-15)
Sender: linux-kernel-owner@vger.kernel.org

On Thu, Feb 27, 2014 at 03:49:47PM +0000, Zoltan Kiss wrote:
> On 27/02/14 12:43, Wei Liu wrote:
> >On Mon, Feb 24, 2014 at 03:08:31PM +0000, Zoltan Kiss wrote:
> >>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?
> >>
> >
> >What's the diff stat if you merge those patches?
> >
> 
>  drivers/net/xen-netback/common.h    |   33 ++-
>  drivers/net/xen-netback/interface.c |   67 +++++-
>  drivers/net/xen-netback/netback.c   |  424
> ++++++++++++++++++++++-------------
>  3 files changed, 362 insertions(+), 162 deletions(-)

Not terribly bad IMHO -- if you look at netback's changelog, I've done
worse. :-P
--
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/