This patch series try to remove the need for any lock in the tun device xmit path, significantly improving the forwarding performance when multiple processes are accessing the tun device (i.e. in a nic->bridge->tun->vm scenario).
The lockless xmit is obtained explicitly setting the NETIF_F_LLTX feature bit and removing the default qdisc. Unlikely most virtual devices, the tun driver has featured a default qdisc for a long period, but it already lost such feature in linux 4.3. Paolo Abeni (2): tun: don't require serialization lock on tx tun: don't set a default qdisc drivers/net/tun.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) -- 1.8.3.1
