SRU: [Lucid] KVM: add schedule check to napi_enable call

[Ken Stailey]

Hi Bruce,

I would like to thank you for your contribution to virtio-net, specifically the "[PATCH] KVM: add schedule check to napi_enable call" as it appears to stabilize virtio-net on Ubuntu Lucid 10.04 LTS.

Stefan Bader is curious to know why that patch is not appearing in upstream linux kernels.  Can you offer any explanation?

Thank you,
Ken Stailey

--- On Mon, 2/7/11, Stefan Bader <stefan.bader at canonical.com> wrote:

> From: Stefan Bader <stefan.bader at canonical.com>
> Subject: Re: SRU: [PATCH] KVM: add schedule check to napi_enable call
> To: kernel-team at lists.ubuntu.com
> Date: Monday, February 7, 2011, 7:50 AM
> On 02/05/2011 09:20 PM, Ken Stailey
> wrote:
> > SRU Justification:
> > 
> > Impact: Under heavy network I/O load virtio-net driver
> crashes making VM guest unusable.
> > 
> > Testcase: I left a current Lucid VM running two
> concurrent "scp -r" of > 200 GB from NFS read-only source
> to a physical remote host overnight.  VM quickly
> started emitting "page allocation errors" in the system
> log.  Next morning when I checked the VM I could still
> ping it but could not establish an SSH connection.
> > 
> > Fix: This patch from Bruce Rogers at Novell
> > 
> >  * [PATCH] KVM: add schedule check to napi_enable
> call
> >     - http://kerneltrap.org/mailarchive/linux-netdev/2010/6/4/6278660
> > 
> > BugLink: https://bugs.launchpad.net/bugs/579276
> > 
> > 
> > 
> The patch itself looks reasonable. But this has not made
> its way upstream. The
> mail thread seems to be reasonably old, so the question
> would be why it is still
> missing. We need patches upstream before they can be SRUed.
> Have you tried
> contacting Bruce or Olaf to ask what happened there?
> 
> -Stefan
> 
> 
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