Re: [PATCH v2 3/3] mm: memcontrol: recursive memory.low protection

[Michal Hocko]

On Thu 13-02-20 10:52:49, Tejun Heo wrote:
> Hello,
> 
> On Thu, Feb 13, 2020 at 04:47:31PM +0100, Michal Hocko wrote:
> > Well, I would tend to agree but I can see an existing cgroup hierarchy
> > imposed by systemd and that is more about "logical" organization of
> > processes based on their purpose than anything resembling resources.
> > So what can we do about that to make it all work?
> 
> systemd right now isn't configuring any resource control by default,
> so I'm not sure why it is relevant in this discussion.

AFAIK systemd already offers knobs to configure resource controls [1].
Besides that we are talking about memcg features which are available only
unified hieararchy and that is what systemd is using already.

> You gotta
> change the layout to configure resource control no matter what and
> it's pretty easy to do. systemd folks are planning to integrate higher
> level resource control features, so my expectation is that the default
> layout is gonna change as it develops.

Do you have any pointers to those discussions? I am not really following
systemd development.

Anyway, I am skeptical that systemd can do anything much more clever
than placing cgroups with a resource control under the root cgroup. At
least not without some tagging which workloads are somehow related.

That being said, I do not really blame systemd here. We are not making
their life particularly easy TBH.

[1] https://www.freedesktop.org/software/systemd/man/systemd.resource-control.html
-- 
Michal Hocko
SUSE Labs