From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [PATCH 0/3] macvlan: support for guest vm direct rx/tx Date: Fri, 27 Nov 2009 21:38:24 -0800 Message-ID: <20091127213824.53c5a23a@nehalam> References: <20091113195201.11184.25766.stgit@mimic.site> <20091113132728.0f1db7c5@s6510> <200911280043.58784.arnd@arndb.de> <20091127.161957.243886653.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: arnd@arndb.de, pmullaney@novell.com, kaber@trash.net, netdev@vger.kernel.org, alacrityvm-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, bridge@lists.linux-foundation.org To: David Miller Return-path: In-Reply-To: <20091127.161957.243886653.davem@davemloft.net> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Fri, 27 Nov 2009 16:19:57 -0800 (PST) David Miller wrote: > From: Arnd Bergmann > Date: Sat, 28 Nov 2009 00:43:58 +0100 > > > On Friday 13 November 2009, Stephen Hemminger wrote: > >> Also, macvlan should really being calling netif_receive_skb() > >> not going through another queue/softirq cycle. > > > > I've added a patch for this in my experimental queue now. > > When I last tried this, I saw a kernel stack overflow > > but it seems fine now. > > I think it is unwise for any virtual device layer to use netif_receive_skb(). > Just like tunnels they should always use netif_rx(). > > Otherwise stack overflow is a very real concern. Maybe we should figure out a way for protocols to return new skb in netif_receive_skb to avoid extra softirq, but avoid stack overflow? --