On Wed 20-05-20 20:09:06, Chris Down wrote:
> Hi Naresh,
>
> Naresh Kamboju writes:
> > As a part of investigation on this issue LKFT teammate Anders Roxell
> > git bisected the problem and found bad commit(s) which caused this problem.
> >
> > The following two patches have been reverted on next-20200519 and retested the
> > reproducible steps and confirmed the test case mkfs -t ext4 got PASS.
> > ( invoked oom-killer is gone now)
> >
> > Revert "mm, memcg: avoid stale protection values when cgroup is above
> > protection"
> > This reverts commit 23a53e1c02006120f89383270d46cbd040a70bc6.
> >
> > Revert "mm, memcg: decouple e{low,min} state mutations from protection
> > checks"
> > This reverts commit 7b88906ab7399b58bb088c28befe50bcce076d82.
>
> Thanks Anders and Naresh for tracking this down and reverting.
>
> I'll take a look tomorrow. I don't see anything immediately obviously wrong
> in either of those commits from a (very) cursory glance, but they should
> only be taking effect if protections are set.
Agreed. If memory.{low,min} is not used then the patch should be
effectively a nop. Btw. do you see the problem when booting with
cgroup_disable=memory kernel command line parameter?
I suspect that something might be initialized for memcg incorrectly and
the patch just makes it more visible for some reason.
--
Michal Hocko
SUSE Labs
