Currently, while when an OVS or Linux bridge is used to forward frames towards some tunnel device, a skb_head_copy() may occur if the ingress device do not provide enough headroom for the tx encapsulation.
This patch series tries to address the issue implementing a new ndo operation to allow the master device to control the headroom used when allocating the skb on frame reception. Said operation is used by the Linux bridge to notify the bridged ports of needed_headroom changes, and similar bookkeeping and behaviour is also added to openvswitch, on a per datapath basis. Finally, the operation is implemented for veth and tun device, which give performance improvement in the 6-12% range when forwarding frames from said devices towards a vxlan tunnel. Paolo Abeni (5): netdev: introduce ndo_set_rx_headroom bridge: notify ensabled devices of headroom changes ovs: propagate per dp max headroom to all vports net/tun: implement ndo_set_rx_headroom veth: implement ndo_set_rx_headroom drivers/net/tun.c | 16 +++++++++++- drivers/net/veth.c | 26 +++++++++++++++++++ include/linux/netdevice.h | 20 +++++++++++++++ net/bridge/br_if.c | 36 +++++++++++++++++++++++++-- net/openvswitch/datapath.c | 48 ++++++++++++++++++++++++++++++++++++ net/openvswitch/datapath.h | 4 +++ net/openvswitch/vport-internal_dev.c | 10 +++++++- 7 files changed, 156 insertions(+), 4 deletions(-) -- 1.8.3.1
