From mboxrd@z Thu Jan  1 00:00:00 1970
From: Neil Horman <nhorman@redhat.com>
Subject: Re: tun: Use netif_receive_skb instead of netif_rx
Date: Wed, 19 May 2010 08:05:47 -0400
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Cc: Herbert Xu <herbert@gondor.hengli.com.au>,
	"David S. Miller" <davem@davemloft.net>,
	Thomas Graf <tgraf@redhat.com>, netdev@vger.kernel.org
To: Eric Dumazet <eric.dumazet@gmail.com>
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On Wed, May 19, 2010 at 10:18:09AM +0200, Eric Dumazet wrote:
> Le mercredi 19 mai 2010 =E0 10:09 +0200, Eric Dumazet a =E9crit :
>=20
> > Another concern I have is about RPS.
> >=20
> > netif_receive_skb() must be called from process_backlog() context, =
or
> > there is no guarantee the IPI will be sent if this skb is enqueued =
for
> > another cpu.
>=20
> Hmm, I just checked again, and this is wrong.
>=20
> In case we enqueue skb on a remote cpu backlog, we also
> do __raise_softirq_irqoff(NET_RX_SOFTIRQ); so the IPI will be done
> later.
>=20
But if this happens, then we loose the connection between the packet be=
ing
received and the process doing the reception, so the network cgroup cla=
ssifier
breaks again.

Performance gains are still a big advantage here of course.
Neil