tree 1393cffb15545baf0cb514096d274b4aa33c5c50
parent 2e7ad56aa54778de863998579fc6b5ff52838571
author Paolo Abeni <pabeni@redhat.com> 1541583276 +0100
committer David S. Miller <davem@davemloft.net> 1541658136 -0800

tun: compute the RFS hash only if needed.

The tun XDP sendmsg code path, unconditionally computes the symmetric
hash of each packet for RFS's sake, even when we could skip it. e.g.
when the device has a single queue.

This change adds the check already in-place for the skb sendmsg path
to avoid unneeded hashing.

The above gives small, but measurable, performance gain for VM xmit
path when zerocopy is not enabled.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>