From 163e529200af7b7521fbde5dbcc653cf3ce597df Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Fri, 26 Feb 2016 10:45:41 +0100 Subject: [PATCH] veth: implement ndo_set_rx_headroom The rx headroom for veth dev is the peer device needed_headroom. Avoid ping-pong updates setting the private flag IFF_PHONY_HEADROOM. This avoids skb head reallocation when forwarding from a veth dev towards a device adding some kind of encapsulation. When transmitting frames below the MTU size towards a vxlan device, this gives about 10% performance speed-up when OVS is used to connect the veth and the vxlan device and a little more when using a plain Linux bridge. Signed-off-by: Paolo Abeni Signed-off-by: David S. Miller --- drivers/net/veth.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/drivers/net/veth.c b/drivers/net/veth.c index ba21d072be31..4f30a6ae50d0 100644 --- a/drivers/net/veth.c +++ b/drivers/net/veth.c @@ -35,6 +35,7 @@ struct pcpu_vstats { struct veth_priv { struct net_device __rcu *peer; atomic64_t dropped; + unsigned requested_headroom; }; /* @@ -271,6 +272,29 @@ static int veth_get_iflink(const struct net_device *dev) return iflink; } +static void veth_set_rx_headroom(struct net_device *dev, int new_hr) +{ + struct veth_priv *peer_priv, *priv = netdev_priv(dev); + struct net_device *peer; + + if (new_hr < 0) + new_hr = 0; + + rcu_read_lock(); + peer = rcu_dereference(priv->peer); + if (unlikely(!peer)) + goto out; + + peer_priv = netdev_priv(peer); + priv->requested_headroom = new_hr; + new_hr = max(priv->requested_headroom, peer_priv->requested_headroom); + dev->needed_headroom = new_hr; + peer->needed_headroom = new_hr; + +out: + rcu_read_unlock(); +} + static const struct net_device_ops veth_netdev_ops = { .ndo_init = veth_dev_init, .ndo_open = veth_open, @@ -285,6 +309,7 @@ static const struct net_device_ops veth_netdev_ops = { #endif .ndo_get_iflink = veth_get_iflink, .ndo_features_check = passthru_features_check, + .ndo_set_rx_headroom = veth_set_rx_headroom, }; #define VETH_FEATURES (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_ALL_TSO | \ @@ -301,6 +326,7 @@ static void veth_setup(struct net_device *dev) dev->priv_flags &= ~IFF_TX_SKB_SHARING; dev->priv_flags |= IFF_LIVE_ADDR_CHANGE; dev->priv_flags |= IFF_NO_QUEUE; + dev->priv_flags |= IFF_PHONY_HEADROOM; dev->netdev_ops = &veth_netdev_ops; dev->ethtool_ops = &veth_ethtool_ops; -- GitLab