Re: [PATCH 4/9] cgroup: Print warning when /proc/cgroups is read on v2-only system

[Waiman Long]

On 3/5/25 5:17 AM, Michal Koutný wrote:
> On Tue, Mar 04, 2025 at 06:55:02AM -1000, Tejun Heo <tj@xxxxxxxxxx> wrote:
> > I'm hoping that we could deprecate /proc/cgroups entirely. Maybe we can just
> > warn whenever the file is accessed?
> I added the guard with legacy systems (i.e. make this backportable) in
> mind which start with no cgroupfs mounted at all and until they decide
> to continue either v1 or v2 way, looking at /proc/cgroups is fine.
> It should warn users that look at /proc/cgroups in cases when it bears
> no valid information.

I like the idea of warning users about using /etc/cgroups if no v1 
filesystem is mounted. It makes sense to make it backportable to older 
kernel. We can always add a follow-up patch later to always warn about it.

Acked-by: Waiman Long <longman@xxxxxxxxxx>