Re: [PATCH 1/4 v2] cgroup: move cgroup_rstat from cgroup to cgroup_subsys_state

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

On Sat, Mar 01, 2025 at 01:25:03AM +0000, Yosry Ahmed wrote:
> On Fri, Feb 28, 2025 at 05:06:23PM -0800, JP Kobryn wrote:
[...]
> > > 
> > > We should call bpf_rstat_flush() only if (!pos->ss) as well, right?
> > > Otherwise we will call BPF rstat flush whenever any subsystem is
> > > flushed.
> > > 
> > > I guess it's because BPF can now pass any subsystem to
> > > cgroup_rstat_flush(), and we don't keep track. I think it would be
> > > better if we do not allow BPF programs to select a css and always make
> > > them flush the self css.
> > > 
> > > We can perhaps introduce a bpf_cgroup_rstat_flush() wrapper that takes
> > > in a cgroup and passes cgroup->self internally to cgroup_rstat_flush().
> > 
> > I'm fine with this if others are in agreement. A similar concept was
> > done in v1.
> 
> Let's wait for Shakeel to chime in here since he suggested removing this
> hook, but I am not sure if he intended to actually do it or not. Better
> not to waste effort if this will be gone soon anyway.
> 

Yes, let's remove this unused hook. JP, can you please followup after
this series with the removal/deprecation of this? One thing we might
want to careful about is if in future someone to add this functionality
again, that would not be a clean revert but what Yosry is asking for.