net: rx_dropped accounting

Under load, netif_rx() can drop incoming packets but administrators dont
have a chance to spot which device needs some tuning (RPS activation for
example)

This patch adds rx_dropped accounting in vlans and tunnels.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 8 insertions, 3 deletions

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index fc20e687e933..714b6a80361d 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -647,9 +647,11 @@ static int ipgre_rcv(struct sk_buff *skb)
                 skb_reset_network_header(skb);
                 ipgre_ecn_decapsulate(iph, skb);
 
-                netif_rx(skb);
+                if (netif_rx(skb) == NET_RX_DROP)
+                        stats->rx_dropped++;
+
                 rcu_read_unlock();
-                return(0);
+                return 0;
         }
         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
 
diff --git a/net/ipv4/ipip.c b/net/ipv4/ipip.c
index 8de8888dc95a..babd25278106 100644
--- a/net/ipv4/ipip.c
+++ b/net/ipv4/ipip.c
@@ -377,7 +377,10 @@ static int ipip_rcv(struct sk_buff *skb)
                 skb_tunnel_rx(skb, tunnel->dev);
 
                 ipip_ecn_decapsulate(iph, skb);
-                netif_rx(skb);
+
+                if (netif_rx(skb) == NET_RX_DROP)
+                        tunnel->dev->stats.rx_dropped++;
+
                 rcu_read_unlock();
                 return 0;
         }