Hi, On Mon, 2018-07-16 at 16:39 -0700, Cong Wang wrote: > On Fri, Jul 13, 2018 at 2:55 AM Paolo Abeni <pab...@redhat.com> wrote: > > > > When mirred is invoked from the ingress path, and it wants to redirect > > the processed packet, it can now use the ACT_REDIRECT action, > > filling the tcf_result accordingly. > > > > This avoids a skb_clone() in the TC S/W data path giving a ~10% > > improvement in forwarding performances. Overall TC S/W performances > > are now comparable to the kernel openswitch datapath.
Thank you for the feedback. > Avoiding skb_clone() for redirection is cool, but why need to use > skb_do_redirect() here? Well, it's not needed. I tried to reduce code duplication, and I tried to avoid adding another TC_ACT_* value. > There is a subtle difference here: > > skb_do_redirect() calls __bpf_rx_skb() which calls > dev_forward_skb(). > > while the current mirred action doesn't scrub packets when > redirecting to ingress (from egress). Although I forget if it is > intentionally. Understood. A possible option out of this issues would be adding another action value - TC_ACT_MIRRED ? - and handle it in sch_handle_egress()[1] with the appropriate semantic. That should address also Daniel and Eyal concerns. Would you consider the above acceptable? Thanks, Paolo
