Re: ipgre rss is broken since gro

[David Miller <davem@davemloft.net>]

From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Mon, 10 Dec 2012 08:54:31 -0800

> I believe performance problem might come from the
> skb_set_queue_mapping(skb, 0); in __skb_tunnel_rx()
> 
> So all packets are queued into a single GRO queue, instead of being
> split as intended in multiple queues.
> 
> I cant find why we must clear queue_mapping, so could you try :

Tom says:

commit 693019e90ca45d881109d32c0c6d29adf03f6447
Author: Tom Herbert <therbert@google.com>
Date:   Thu Sep 23 11:19:54 2010 +0000

    net: reset skb queue mapping when rx'ing over tunnel
    
    Reset queue mapping when an skb is reentering the stack via a tunnel.
    On second pass, the queue mapping from the original device is no
    longer valid.
    
    Signed-off-by: Tom Herbert <therbert@google.com>
    Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/dst.h b/include/net/dst.h
index 81d1413..0238650 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -242,6 +242,7 @@ static inline void skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev)
 	dev->stats.rx_packets++;
 	dev->stats.rx_bytes += skb->len;
 	skb->rxhash = 0;
+	skb_set_queue_mapping(skb, 0);
 	skb_dst_drop(skb);
 	nf_reset(skb);
 }