Re: [LSF/MM/BPF TOPIC] Reducing zombie memcgs

[Alistair Popple <apopple@nvidia.com>]

Jason Gunthorpe <jgg@nvidia.com> writes:

> On Fri, May 12, 2023 at 06:45:13PM +1000, Alistair Popple wrote:
>
>> However review comments suggested it needed to be added as part of
>> memcg. As soon as we do that we have to address how we deal with shared
>> memory. If we stick with the original RLIMIT proposal this discussion
>> goes away, but based on feedback I think I need to at least investigate
>> integrating it into memcg to get anything merged.
>
> Personally I don't see how we can effectively solve the per-page
> problem without also tracking all the owning memcgs for every
> page. This means giving each struct page an array of memcgs
>
> I suspect this will be too expensive to be realistically
> implementable.

Yep, agree with that. Tracking the list of memcgs was the main problem
that prevented this.

> If it is done then we may not even need a pin controller on its own as
> the main memcg should capture most of it. (althought it doesn't
> distinguish between movable/swappable and non-swappable memory)
>
> But this is all being done for the libvirt people, so it would be good
> to involve them

Do you know of anyone specifically there that is interested in this?
I've rebased my series on latest upstream and am about to resend it so
would be good to get some feedback from them.

Thanks.

> Jason