Re: [PATCH V8 0/4 net-next] macvtap/vhost TX zero-copy support

From: Michael S. Tsirkin
Date: Thu Jul 07 2011 - 07:37:04 EST


On Thu, Jul 07, 2011 at 04:08:40AM -0700, David Miller wrote:
> From: Shirley Ma <mashirle@xxxxxxxxxx>
> Date: Wed, 06 Jul 2011 15:15:25 -0700
>
> > This patchset add supports for TX zero-copy between guest and host
> > kernel through vhost. It significantly reduces CPU utilization on the
> > local host on which the guest is located (It reduced about 50% CPU usage
> > for single stream test on the host, while 4K message size BW has
> > increased about 50%). The patchset is based on previous submission and
> > comments from the community regarding when/how to handle guest kernel
> > buffers to be released. This is the simplest approach I can think of
> > after comparing with several other solutions.
> >
> > This patchset has integrated V3 review comments from community:
>
> I'm personally fine with this patch set. Unless there are others
> who object, please fix the use-after-free bug I reported, respin
> the patch set, and I'll apply it.
>
> Thanks.

There's the FIXME in patch 4 where it spins in vhost waiting for
the pages to get freed. I'm fixing that up as Shirley's on vacation.

Apply patches 1-3 for now?

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