Re: [PATCH v3 net-next 12/12] net-memcg: Decouple controlled memcg from global protocol memory accounting.

[Shakeel Butt <shakeel.butt@linux.dev>]

On Wed, Aug 13, 2025 at 09:34:01PM -0700, Kuniyuki Iwashima wrote:
> On Wed, Aug 13, 2025 at 5:55 PM Martin KaFai Lau <martin.lau@linux.dev> wrote:
> >
> > On 8/13/25 1:53 PM, Shakeel Butt wrote:
> > > What I think is the right approach is to have BPF struct ops based
> > > approach with possible callback 'is this socket under pressure' or maybe
> > > 'is this socket isolated' and then you can do whatever you want in those
> > > callbacks. In this way your can follow the same approach of caching the
> > > result in kernel (lower bits of sk->sk_memcg).
> > >
> > > I am CCing bpf list to get some suggestions or concerns on this
> > > approach.
> >
> > I have quickly looked at the set. In patch 11, it sets a bit in sk->sk_memcg.
> >
> > On the bpf side, there are already cgroup bpf progs that can do bpf_setsockopt
> > on a sk, so the same can be done here. The bpf_setsockopt does not have to set
> > option/knob that is only available in the uapi in case we don't want to expose
> > this to the user space.
> >
> > The cgroup bpf prog (BPF_CGROUP_INET_SOCK_CREATE) can already be run when a
> > "inet" sock is created. This hook (i.e. attach_type) does not have access to
> > bpf_setsockopt but should be easy to add.
> 
> Okay, I will try the bpf_setsockopt() approach.
> Should I post patch 1-10 to net-next separately ?
> They are pure net material to gather memcg code under CONFIG_MEMCG.

Yes please.