Subject: [PATCH net-next v3 0/5] TC: refactor act_mirred packets re-injection

From: Paolo Abeni <[email-masked]>
Date: Tue, 24 Jul 2018 22:06:38 +0200

This series is aimed at improving the act_mirred redirect performances.
Such action is used by OVS to represent TC S/W flows, and it's current largest
bottle-neck is the need for a skb_clone() for each packet.

The first 3 patches introduce some cleanup and safeguards to allow extending 
tca_result - we will use it to store RCU protected redirect information - and
introduce a clear separation between user-space accessible tcfa_action
value and internal values accessible only by the kernel.
Then a new tcfa_action value is introduced: TC_ACT_REINJECT, similar to
TC_ACT_REDIRECT, but preserving the mirred semantic. Such value is not
accessible from user-space.
The last patch exploits the newly introduced infrastructure in the act_mirred
action, to avoid a skb_clone, when possible.

Overall this the above gives a ~10% performance improvement in forwarding tput,
when using the TC S/W datapath.

v1 -> v2:
 - preserve the rcu lock in act_bpf
 - add and use a new action value to reinject the packets, preserving the mirred
   semantic

v2 -> v3:
 - renamed to new action as TC_ACT_REINJECT
 - TC_ACT_REINJECT is not exposed to user-space

Paolo Abeni (5):
  tc/act: user space can't use TC_ACT_REDIRECT directly
  net/sched: user-space can't set unknown tcfa_action values
  tc/act: remove unneeded RCU lock in action callback
  net/tc: introduce TC_ACT_REINJECT.
  act_mirred: use TC_ACT_REINJECT when possible

 include/net/act_api.h        |  2 +-
 include/net/pkt_cls.h        |  3 +++
 include/net/sch_generic.h    | 21 ++++++++++++++++++++
 include/uapi/linux/pkt_cls.h |  6 ++++--
 net/core/dev.c               |  6 +++++-
 net/sched/act_api.c          | 15 +++++++++++++-
 net/sched/act_csum.c         | 12 +++---------
 net/sched/act_ife.c          |  5 +----
 net/sched/act_mirred.c       | 38 ++++++++++++++++++++++++------------
 net/sched/act_sample.c       |  4 +---
 net/sched/act_skbedit.c      | 10 +++-------
 net/sched/act_skbmod.c       | 21 +++++++++-----------
 net/sched/act_tunnel_key.c   |  6 +-----
 net/sched/act_vlan.c         | 19 +++++++-----------
 14 files changed, 98 insertions(+), 70 deletions(-)

-- 
2.17.1