Re: [PATCH] KVM: arm: memcg awareness

From: Marc Zyngier
Date: Wed Mar 17 2021 - 05:16:38 EST


On Wed, 17 Mar 2021 08:04:20 +0000,
Wanpeng Li <kernellwp@xxxxxxxxx> wrote:
>
> On Wed, 17 Mar 2021 at 15:57, Michal Hocko <mhocko@xxxxxxxx> wrote:
> >
> > On Wed 17-03-21 13:46:24, Wanpeng Li wrote:
> > > From: Wanpeng Li <wanpengli@xxxxxxxxxxx>
> > >
> > > KVM allocations in the arm kvm code which are tied to the life
> > > of the VM process should be charged to the VM process's cgroup.
> >
> > How much memory are we talking about?
> >
> > > This will help the memcg controler to do the right decisions.
> >
> > This is a bit vague. What is the right decision? AFAICS none of that
> > memory is considered during oom victim selection. The only thing memcg
> > controler can help with is to contain and account this additional
> > memory. This might help to better isolate multiple workloads on the same
> > system. Maybe this is what you wanted to say? Or maybe this is a way to
> > prevent untrusted users from consuming a lot of memory?
>
> It is explained in this patchset for x86 kvm which is upstream, I
> think I don't need to copy and paste. :)

You expect us to review your patches, don't you?

Surely you can afford to explain why I should consider it at all. And
if you cannot be bothered, maybe I shouldn't either.

M.

--
Without deviation from the norm, progress is not possible.