Re: [RFC Patch net-next 0/6] net_sched: really switch to RCU for tc actions

Fri, Sep 02, 2016 at 07:57:14AM CEST, xiyou.wangcong@gmail.com wrote:

Currently there are only two tc actions lockless:
gact and mirred. But they are questionable because
we don't have anything to prevent a parallel update
on an existing tc action in hash table while reading
it on fast path, this could be a problem when a tc
action becomes complex.

This patchset introduces a few new tc action API's
based on RCU so that the fast path could now really
be protected by RCU and we can update existing tc
actions safely and race-freely.

Obviously this is still _not_ complete yet, I only
modified mirred action to show the use case of
the new API's, all the rest actions could switch to
the new API's too. The new API's are a bit ugly too,
any suggestion to improve them is welcome.

I tested mirred action with a few test cases, so far
so good, at least no obvious bugs. ;)

I wonder, do you happen to have a very tiny narrow screen?