From 183dea5818315c0a172d21ecbcd2554894bf01e3 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Thu, 30 Nov 2017 15:35:33 +0100 Subject: openvswitch: do not propagate headroom updates to internal port After commit 3a927bc7cf9d ("ovs: propagate per dp max headroom to all vports") the need_headroom for the internal vport is updated accordingly to the max needed headroom in its datapath. That avoids the pskb_expand_head() costs when sending/forwarding packets towards tunnel devices, at least for some scenarios. We still require such copy when using the ovs-preferred configuration for vxlan tunnels: br_int / \ tap vxlan (remote_ip:X) br_phy \ NIC where the route towards the IP 'X' is via 'br_phy'. When forwarding traffic from the tap towards the vxlan device, we will call pskb_expand_head() in vxlan_build_skb() because br-phy->needed_headroom is equal to tun->needed_headroom. With this change we avoid updating the internal vport needed_headroom, so that in the above scenario no head copy is needed, giving 5% performance improvement in UDP throughput test. As a trade-off, packets sent from the internal port towards a tunnel device will now experience the head copy overhead. The rationale is that the latter use-case is less relevant performance-wise. Signed-off-by: Paolo Abeni Acked-by: Pravin B Shelar Signed-off-by: David S. Miller --- net/openvswitch/vport-internal_dev.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) (limited to 'net/openvswitch') diff --git a/net/openvswitch/vport-internal_dev.c b/net/openvswitch/vport-internal_dev.c index 04a3128adcf0..3e7747549f90 100644 --- a/net/openvswitch/vport-internal_dev.c +++ b/net/openvswitch/vport-internal_dev.c @@ -126,18 +126,12 @@ internal_get_stats(struct net_device *dev, struct rtnl_link_stats64 *stats) } } -static void internal_set_rx_headroom(struct net_device *dev, int new_hr) -{ - dev->needed_headroom = new_hr < 0 ? 0 : new_hr; -} - static const struct net_device_ops internal_dev_netdev_ops = { .ndo_open = internal_dev_open, .ndo_stop = internal_dev_stop, .ndo_start_xmit = internal_dev_xmit, .ndo_set_mac_address = eth_mac_addr, .ndo_get_stats64 = internal_get_stats, - .ndo_set_rx_headroom = internal_set_rx_headroom, }; static struct rtnl_link_ops internal_dev_link_ops __read_mostly = { @@ -154,7 +148,7 @@ static void do_setup(struct net_device *netdev) netdev->priv_flags &= ~IFF_TX_SKB_SHARING; netdev->priv_flags |= IFF_LIVE_ADDR_CHANGE | IFF_OPENVSWITCH | - IFF_PHONY_HEADROOM | IFF_NO_QUEUE; + IFF_NO_QUEUE; netdev->needs_free_netdev = true; netdev->priv_destructor = internal_dev_destructor; netdev->ethtool_ops = &internal_dev_ethtool_ops; @@ -195,7 +189,6 @@ static struct vport *internal_dev_create(const struct vport_parms *parms) err = -ENOMEM; goto error_free_netdev; } - vport->dev->needed_headroom = vport->dp->max_headroom; dev_net_set(vport->dev, ovs_dp_get_net(vport->dp)); internal_dev = internal_dev_priv(vport->dev); -- cgit