diff options
| author | Paolo Abeni <pabeni@redhat.com> | 2016-02-26 10:45:40 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-03-01 15:54:30 -0500 |
| commit | eaea34b23c46bf17b4a5638be69ab3561854f34b (patch) | |
| tree | 1a2182f40f905d60de941bda9513864eb22fe9ab | |
| parent | 3a927bc7cf9d0fbe8f4a8189dd5f8440228f64e7 (diff) | |
net/tun: implement ndo_set_rx_headroom
ndo_set_rx_headroom controls the align value used by tun devices to
allocate skbs on frame reception.
When the xmit device adds a large encapsulation, this avoids an skb
head reallocation on forwarding.
The measured improvement when forwarding towards a vxlan dev with
frame size below the egress device MTU is as follow:
vxlan over ipv6, bridged: +6%
vxlan over ipv6, ovs: +7%
In case of ipv4 tunnels there is no improvement, since the tun
device default alignment provides enough headroom to avoid the skb
head reallocation.
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | drivers/net/tun.c | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 88bb8cc3555b..afdf950617c3 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -187,6 +187,7 @@ struct tun_struct { #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \ NETIF_F_TSO6|NETIF_F_UFO) + int align; int vnet_hdr_sz; int sndbuf; struct tap_filter txflt; @@ -934,6 +935,17 @@ static void tun_poll_controller(struct net_device *dev) return; } #endif + +static void tun_set_headroom(struct net_device *dev, int new_hr) +{ + struct tun_struct *tun = netdev_priv(dev); + + if (new_hr < NET_SKB_PAD) + new_hr = NET_SKB_PAD; + + tun->align = new_hr; +} + static const struct net_device_ops tun_netdev_ops = { .ndo_uninit = tun_net_uninit, .ndo_open = tun_net_open, @@ -945,6 +957,7 @@ static const struct net_device_ops tun_netdev_ops = { #ifdef CONFIG_NET_POLL_CONTROLLER .ndo_poll_controller = tun_poll_controller, #endif + .ndo_set_rx_headroom = tun_set_headroom, }; static const struct net_device_ops tap_netdev_ops = { @@ -962,6 +975,7 @@ static const struct net_device_ops tap_netdev_ops = { .ndo_poll_controller = tun_poll_controller, #endif .ndo_features_check = passthru_features_check, + .ndo_set_rx_headroom = tun_set_headroom, }; static void tun_flow_init(struct tun_struct *tun) @@ -1086,7 +1100,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) }; struct sk_buff *skb; size_t total_len = iov_iter_count(from); - size_t len = total_len, align = NET_SKB_PAD, linear; + size_t len = total_len, align = tun->align, linear; struct virtio_net_hdr gso = { 0 }; int good_linear; int copylen; @@ -1694,6 +1708,7 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) tun->txflt.count = 0; tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr); + tun->align = NET_SKB_PAD; tun->filter_attached = false; tun->sndbuf = tfile->socket.sk->sk_sndbuf; |