From: "Michael S. Tsirkin" <mst@redhat.com>
To: Herbert Xu <herbert@gondor.hengli.com.au>
Cc: Shirley Ma <mashirle@us.ibm.com>,
davem@davemloft.net, netdev@vger.kernel.org, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next] skbuff: clear tx zero-copy flag
Date: Mon, 25 Jul 2011 12:44:14 +0300 [thread overview]
Message-ID: <20110725094414.GA11776@redhat.com> (raw)
In-Reply-To: <20110725084057.GA30311@gondor.apana.org.au>
On Mon, Jul 25, 2011 at 04:40:57PM +0800, Herbert Xu wrote:
> On Mon, Jul 25, 2011 at 11:07:43AM +0300, Michael S. Tsirkin wrote:
> >
> > However macvtap passes an skb directly to the
> > lower device, so as long as macvtap is the only user
> > of that interface, we are fine I think - there's
> > no way for an skb to get from macvtap to splice
> > read path I think.
> >
> > Right?
>
> Yes, as long as you can guarantee that the skb never loops back
> then you should be fine.
>
> However, does macvtap really bypass everything, including the
> qdisc layer? The qdisc layer is certainly capable of looping
> the skb back with the redirect action.
>
> Cheers,
No, I don't think macvtap bypasses the qdisc.
Is the action in question here?
static int tcf_mirred(struct sk_buff *skb,
const struct tc_action *a,
struct tcf_result *res)
if yes that seems to always clone an skb, which in turn
does the copy so we are fine?
> --
> Email: Herbert Xu <herbert@gondor.apana.org.au>
> Home Page: http://gondor.apana.org.au/~herbert/
> PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
next prev parent reply other threads:[~2011-07-25 9:44 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-09 7:12 [PATCH net-next] skbuff: clear tx zero-copy flag Shirley Ma
2011-07-09 9:55 ` David Miller
2011-07-25 0:42 ` Herbert Xu
2011-07-25 8:07 ` Michael S. Tsirkin
2011-07-25 8:40 ` Herbert Xu
2011-07-25 9:44 ` Michael S. Tsirkin [this message]
2011-07-25 9:57 ` Herbert Xu
2011-07-25 10:02 ` David Miller
2011-07-25 10:53 ` Michael S. Tsirkin
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