Re: mm: mkfs.ext4 invoked oom-killer on i386 - pagecache_get_page

Naresh Kamboju
2020-05-21T19:00:13Z

On Thu, 21 May 2020 at 22:04, Michal Hocko <mhocko@kernel.org> wrote:
>
> On Thu 21-05-20 11:55:16, Michal Hocko wrote:
> > 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.
>
> I was staring into the code and did not see anything. Could you give the
> following debugging patch a try and see whether it triggers?

These code paths did not touch it seems. but still see the reported problem.
Please find a detailed test log output [1]

And
One more test log with cgroup_disable=memory [2]

Test log link,
[1] https://pastebin.com/XJU7We1g
[2] https://pastebin.com/BZ0BMUVt