[RFC PATCH net-next 00/12] XDP batching for TUN/vhost_net

[Jason Wang <jasowang@redhat.com>]

Hi all:

We do not support XDP batching for TUN since it can only receive one
packet a time from vhost_net. This series tries to remove this
limitation by:

- introduce a TUN specific msg_control that can hold a pointer to an
  array of XDP buffs
- try copy and build XDP buff in vhost_net
- store XDP buffs in an array and submit them once for every N packets
  from vhost_net
- since TUN can only do native XDP for datacopy packet, to simplify
  the logic, split datacopy out logic and only do batching for
  datacopy.

With this series, TX PPS can improve about 34% from 2.9Mpps to
3.9Mpps when doing xdp_redirect_map between TAP and ixgbe.

Thanks

Jason Wang (12):
  vhost_net: introduce helper to initialize tx iov iter
  vhost_net: introduce vhost_exceeds_weight()
  vhost_net: introduce vhost_has_more_pkts()
  vhost_net: split out datacopy logic
  vhost_net: batch update used ring for datacopy TX
  tuntap: enable premmption early
  tuntap: simplify error handling in tun_build_skb()
  tuntap: tweak on the path of non-xdp case in tun_build_skb()
  tuntap: split out XDP logic
  vhost_net: build xdp buff
  vhost_net: passing raw xdp buff to tun
  vhost_net: batch submitting XDP buffers to underlayer sockets

 drivers/net/tun.c      | 226 +++++++++++++++++++++++++++----------
 drivers/vhost/net.c    | 297 ++++++++++++++++++++++++++++++++++++++++++++-----
 include/linux/if_tun.h |   7 ++
 3 files changed, 444 insertions(+), 86 deletions(-)

-- 
2.7.4