On 16-09-08 10:26 PM, Cong Wang wrote: > On Thu, Sep 8, 2016 at 8:51 AM, Eric Dumazet <eric.duma...@gmail.com> wrote: >> On Thu, 2016-09-08 at 08:47 -0700, John Fastabend wrote: >> >>> Works for me. FWIW I find this plenty straightforward and don't really >>> see the need to make the hash table itself rcu friendly. >>> >>> Acked-by: John Fastabend <john.r.fastab...@intel.com> >>> >> >> Yes, it seems this hash table is used in control path, with RTNL held >> anyway. > > Seriously? You never read hashtable in fast path?? I think you need > to wake up. >
But the actions use refcnt'ing and should never be decremented to zero as long as they can still be referenced by an active filter. If each action handles its parameters like mirred/gact then I don't see why its necessary. I believe though that the refcnt needs to be fixed a bit though most likely by making it atomic. I original assumed it was protected by RTNL lock but because its getting decremented from rcu callback this is not true. .John
