Re: [net-next sample action optimization 3/3] openvswitch: Optimize sample action for the clone use cases

[Andy Zhou <azhou@ovn.org>]

>>> -       skb = skb_clone(skb, GFP_ATOMIC);
>>> -       if (!skb)
>>> -               /* Skip the sample action when out of memory. */
>>> -               return 0;
>>> +       if (key) {
>>> +               err = do_execute_actions(dp, skb, key, actions, rem);
>>> +       } else if (!add_deferred_actions(skb, orig, actions, rem)) {
>>>
>> We can refactor this code to avoid duplicate code all actions
>> implementation. This way there could be single function dealing with
>> both defered action and key fifo arrays.
>
> O.K. I will make the change in the next version.

After looking more at it, the sample action and recirc action are different
enough that I don't see clean ways refactor them. For example, recirc
needs to deal with setting recirc_id.  recirc calls
ovs_dp_process_packet, and sample calls do_execute_action.

>> I am not sure if we can put sample or recirc in "may not change flow"
>> actions list. Consider following set of actions:
>> sample(sample(set-IP)),userpsace(),...
>> In this case the userspace action could recieve skb with inconsistent
>> flow due to preceding of set action nested in the sample action.
>
> Good catch.  Will fix.

What's the objection on recirc action? It always works on clone key.