Re: [PATCH] mm,page_alloc: PF_WQ_WORKER threads must sleep at should_reclaim_retry().

On Tue 31-07-18 06:01:48, Tetsuo Handa wrote:

On 2018/07/31 4:10, Michal Hocko wrote:

quoted

Since should_reclaim_retry() should be a natural reschedule point,
let's do the short sleep for PF_WQ_WORKER threads unconditionally in
order to guarantee that other pending work items are started. This will
workaround this problem and it is less fragile than hunting down when
the sleep is missed. E.g. we used to have a sleeping point in the oom
path but this has been removed recently because it caused other issues.
Having a single sleeping point is more robust.

linux.git has not removed the sleeping point in the OOM path yet. Since removing the
sleeping point in the OOM path can mitigate CVE-2016-10723, please do so immediately.

is this an {Acked,Reviewed,Tested}-by?

I will send the patch to Andrew if the patch is ok. 

(And that change will conflict with Roman's cgroup aware OOM killer patchset. But it
should be easy to rebase.)

That is still a WIP so I would lose sleep over it.
-- 
Michal Hocko
SUSE Labs