Subject: Re: [PATCH RFC] tun: experimental zero copy tx support
From: Shirley Ma <mashirle@us.ibm.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: "David S. Miller" <davem@davemloft.net>,
        Stephen Hemminger <shemminger@vyatta.com>,
        Joe Perches <joe@perches.com>, Jason Wang <jasowang@redhat.com>,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        Ian.Campbell@citrix.com, kvm@vger.kernel.org
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	 <20120514183929.GB17086@redhat.com>
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Date: Wed, 16 May 2012 08:16:55 -0700
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On Mon, 2012-05-14 at 21:39 +0300, Michael S. Tsirkin wrote:
> > Hello Mike,
> > 
> > Have you tested this patch? I think the difference between macvtap
> and
> > tap is tap forwarding the packet to bridge. The zerocopy is disabled
> in
> > this case.
> > 
> > Shirley
> 
> Testing in progress, but the patchset I pointed to enables
> zerocopy with bridge. 

Hello Mike,

You meant this patch or another patchset for enabling bridge zerocopy?

I remembered we disabled forward skb zerocopy since the user space
program might hold the buffers too long or forever.

In tap/bridge case, when the tx buffers will be released?

Thanks
Shirley

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