Merge branch 'udp_tunnel-gro-optimizations'

Paolo Abeni says:

====================
udp_tunnel: GRO optimizations

The UDP tunnel GRO stage is source of measurable overhead for workload
based on UDP-encapsulated traffic: each incoming packets requires a full
UDP socket lookup and an indirect call.

In the most common setups a single UDP tunnel device is used. In such
case we can optimize both the lookup and the indirect call.

Patch 1 tracks per netns the active UDP tunnels and replaces the socket
lookup with a single destination port comparison when possible.

Patch 2 tracks the different types of UDP tunnels and replaces the
indirect call with a static one when there is a single UDP tunnel type
active.

I measure ~5% performance improvement in TCP over UDP tunnel stream
tests on top of this series.

v3: https://lore.kernel.org/netdev/cover.1741632298.git.pabeni@redhat.com/
v2: https://lore.kernel.org/netdev/cover.1741338765.git.pabeni@redhat.com/
v1: https://lore.kernel.org/netdev/cover.1741275846.git.pabeni@redhat.com/
====================

Link: https://patch.msgid.link/cover.1741718157.git.pabeni@redhat.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>