tunnels: Optimize tx path
We currently dirty a cache line to update tunnel device stats
(tx_packets/tx_bytes). We better use the txq->tx_bytes/tx_packets
counters that already are present in cpu cache, in the cache
line shared with txq->_xmit_lock
This patch extends IPTUNNEL_XMIT() macro to use txq pointer
provided by the caller.
Also &tunnel->dev->stats can be replaced by &dev->stats
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/ipip.h b/include/net/ipip.h
index 87acf8f..0159221 100644
--- a/include/net/ipip.h
+++ b/include/net/ipip.h
@@ -42,9 +42,9 @@
ip_select_ident(iph, &rt->u.dst, NULL); \
\
err = ip_local_out(skb); \
- if (net_xmit_eval(err) == 0) { \
- stats->tx_bytes += pkt_len; \
- stats->tx_packets++; \
+ if (likely(net_xmit_eval(err) == 0)) { \
+ txq->tx_bytes += pkt_len; \
+ txq->tx_packets++; \
} else { \
stats->tx_errors++; \
stats->tx_aborted_errors++; \
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 41ada99..89ff9d5 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -662,7 +662,8 @@
static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct ip_tunnel *tunnel = netdev_priv(dev);
- struct net_device_stats *stats = &tunnel->dev->stats;
+ struct net_device_stats *stats = &dev->stats;
+ struct netdev_queue *txq = netdev_get_tx_queue(dev, 0);
struct iphdr *old_iph = ip_hdr(skb);
struct iphdr *tiph;
u8 tos;
@@ -810,7 +811,7 @@
struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
if (!new_skb) {
ip_rt_put(rt);
- stats->tx_dropped++;
+ txq->tx_dropped++;
dev_kfree_skb(skb);
return NETDEV_TX_OK;
}
diff --git a/net/ipv4/ipip.c b/net/ipv4/ipip.c
index 08ccd34..6a55392 100644
--- a/net/ipv4/ipip.c
+++ b/net/ipv4/ipip.c
@@ -390,7 +390,8 @@
static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct ip_tunnel *tunnel = netdev_priv(dev);
- struct net_device_stats *stats = &tunnel->dev->stats;
+ struct net_device_stats *stats = &dev->stats;
+ struct netdev_queue *txq = netdev_get_tx_queue(dev, 0);
struct iphdr *tiph = &tunnel->parms.iph;
u8 tos = tunnel->parms.iph.tos;
__be16 df = tiph->frag_off;
@@ -478,7 +479,7 @@
struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
if (!new_skb) {
ip_rt_put(rt);
- stats->tx_dropped++;
+ txq->tx_dropped++;
dev_kfree_skb(skb);
return NETDEV_TX_OK;
}
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index dbd19a7..99da272 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -555,7 +555,8 @@
struct net_device *dev)
{
struct ip_tunnel *tunnel = netdev_priv(dev);
- struct net_device_stats *stats = &tunnel->dev->stats;
+ struct net_device_stats *stats = &dev->stats;
+ struct netdev_queue *txq = netdev_get_tx_queue(dev, 0);
struct iphdr *tiph = &tunnel->parms.iph;
struct ipv6hdr *iph6 = ipv6_hdr(skb);
u8 tos = tunnel->parms.iph.tos;
@@ -688,7 +689,7 @@
struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
if (!new_skb) {
ip_rt_put(rt);
- stats->tx_dropped++;
+ txq->tx_dropped++;
dev_kfree_skb(skb);
return NETDEV_TX_OK;
}