Re: A path forward to cleaning up dying cgroups?

[Waiman Long]

On 2/5/25 10:30 PM, Muchun Song wrote:
> > On Feb 6, 2025, at 02:46, Shakeel Butt <shakeel.butt@xxxxxxxxx> wrote:
> >
> > On Wed, Feb 05, 2025 at 01:08:42PM -0500, Johannes Weiner wrote:
> > > On Wed, Feb 05, 2025 at 12:50:19PM -0500, Hamza Mahfooz wrote:
> > > > Cc: Shakeel Butt <shakeel.butt@xxxxxxxxx>
> > > >
> > > > On 2/5/25 12:48, Hamza Mahfooz wrote:
> > > > > I was just curious as to what the status of the issue described in [1]
> > > > > is. It appears that the last time someone took a stab at it was in [2].
> > > If memory serves, the sticking point was whether pages should indeed
> > > be reparented on cgroup death, or whether they could be moved
> > > arbitrarily to other cgroups that are still using them.
> > >
> > > It's a bit unfortunate, because the reparenting patches were tested
> > > and reviewed, and the arbitrary recharging was just an idea that
> > > ttbomk nobody seriously followed up on afterwards.
> > >
> > > We also recently removed the charge moving code from cgroup1, along
> > > with the subtle page access/locking/accounting rules it imposed on the
> > > rest of the MM. I'm doubtful there is much appetite in either camp for
> > > bringing this back.
> > >
> > > So I would still love to see Muchun's patches merged. They fix a
> > > seemingly universally experienced operational issue in memcg, and we
> > > shouldn't hold it up unless somebody actually posts alternative code.
> > >
> > > Thoughts?
> > I think the recharging (or whatever the alternative) can be a followup
> > to this. I agree this is a good change.
> I agree with you. We've been encountering dying memory issues for years
> on our servers. As Roman said, I need to refresh my patches. So I need
> some time for refreshing.

Glad to hear that. I have been waiting for a resolution of the dying 
memory cgroup problems for years :-)

Cheers,
Longman