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Re: [Xen-devel] [PATCH] netback: allow arbitrary mtu size until frontend

To: Olaf Hering <olaf@xxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH] netback: allow arbitrary mtu size until frontend connects
From: Ian Campbell <Ian.Campbell@xxxxxxxxxxxxx>
Date: Mon, 7 Feb 2011 09:34:40 +0000
Cc: "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>, Jan Beulich <JBeulich@xxxxxxxxxx>
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On Mon, 2011-02-07 at 09:26 +0000, Olaf Hering wrote:
> On Mon, Feb 07, Jan Beulich wrote:
> > >>> On 06.02.11 at 14:42, Olaf Hering <olaf@xxxxxxxxx> wrote:
> > > Allow arbitrary mtu size until the frontend is connected.  Once the
> > > connection is established, adjust mtu by checking if the backend
> > > supports the 'feature-sg'.  If the backend does support it, keep the
> > > current mtu. Otherwise set it to the default value, which is 1500.
> > > 
> > > This helps the vif-bridge hotplug script to set the mtu size to 9000
> > > while bringing up the guest.
> > 
> > Isn't this functionally the same as
> > http://xenbits.xen.org/XCP/linux-2.6.32.pq.hg?file/043b76e4943c/xen-netback-Allow-setting-of-large-MTU-before-rings.patch
> > or its pv-ops parent 
> > https://git.kernel.org/?p=linux/kernel/git/jeremy/xen.git;a=commitdiff;h=bee2eec2355c4bf4e149a426d5e30527162de566
> > (in which case it would seem preferable to pull in that change)?
> Either approach is ok.
> Could one of the changes be backported and applied to the 2.6.18.hg tree?

I think for the sake of not fragmenting any more than necessary a
backport would be preferable to adding new code to the old trees.

Why are you still running 2.6.18 though?


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