On Fri, Sep 14, 2018 at 3:46 AM Vlad Buslov <vla...@mellanox.com> wrote: > > > On Thu 13 Sep 2018 at 17:13, Cong Wang <xiyou.wangc...@gmail.com> wrote: > > On Wed, Sep 12, 2018 at 1:51 AM Vlad Buslov <vla...@mellanox.com> wrote: > >> > >> > >> On Fri 07 Sep 2018 at 19:12, Cong Wang <xiyou.wangc...@gmail.com> wrote: > >> > On Fri, Sep 7, 2018 at 6:52 AM Vlad Buslov <vla...@mellanox.com> wrote: > >> >> > >> >> Action API was changed to work with actions and action_idr in > >> >> concurrency > >> >> safe manner, however tcf_del_walker() still uses actions without taking > >> >> a > >> >> reference or idrinfo->lock first, and deletes them directly, > >> >> disregarding > >> >> possible concurrent delete. > >> >> > >> >> Add tc_action_wq workqueue to action API. Implement > >> >> tcf_idr_release_unsafe() that assumes external synchronization by caller > >> >> and delays blocking action cleanup part to tc_action_wq workqueue. > >> >> Extend > >> >> tcf_action_cleanup() with 'async' argument to indicate that function > >> >> should > >> >> free action asynchronously. > >> > > >> > Where exactly is blocking in tcf_action_cleanup()? > >> > > >> > From your code, it looks like free_tcf(), but from my observation, > >> > the only blocking function inside is tcf_action_goto_chain_fini() > >> > which calls __tcf_chain_put(). But, __tcf_chain_put() is blocking > >> > _ONLY_ when tc_chain_notify() is called, for tc action it is never > >> > called. > >> > > >> > So, what else is blocking? > >> > >> __tcf_chain_put() calls tc_chain_tmplt_del(), which calls > >> ops->tmplt_destroy(). This last function uses hw offload API, which is > >> blocking. > > > > Good to know. > > > > Can we just make ops->tmplt_destroy() to use workqueue? > > Making tc action to workqueue seems overkill, for me. > > How about changing tcf_chain_put_by_act() to use tc_filter_wq, instead > of directly calling __tcf_chain_put()? IMO it is a better solution > because it benefits all classifiers, instead of requiring every > classifier with templates support to implement non-blocking > ops->tmplt_destroy().
My point is, there is only one filter implements ops->tmplt_destroy so far, so there is no reason to just make all filters to adjusted for this single one. Not to mention actions, actions are innocent here.
