Re: [PATCH] mm,oom: Do not unfreeze OOM victim thread.

[Michal Hocko <mhocko@kernel.org>]

On Thu 29-03-18 23:36:58, Tetsuo Handa wrote:
> Currently, mark_oom_victim() calls __thaw_task() on the OOM victim
> threads and freezing_slow_path() unfreezes the OOM victim thread.
> But I think this exceptional behavior makes little sense nowadays.

Well, I would like to see this happen because it would allow more
changes on top. E.g. get rid of TIF_MEMDIE finally. But I am not really
sure we are there yet. OOM reaper is useful tool but it still cannot
help in some cases (shared memory, a lot of metadata allocated on behalf
of the process etc...). Considering that the freezing can be an
unprivileged operation (think cgroup freezer) then I am worried that
one container can cause the global oom killer and hide oom victims to
the fridge and spill over to other containers. Maybe I am overly
paranoid and this scenario is not even all that interesting but I would
like to hear a better justification which explains all these cases
rather than "we have oom reaper so we are good to go" rationale.
-- 
Michal Hocko
SUSE Labs