Re: [RFC PATCH v5 19/29] sched/rt: Remove support for cgroups-v1

[Juri Lelli]

On 05/05/26 17:01, Peter Zijlstra wrote:
> On Thu, Apr 30, 2026 at 11:38:23PM +0200, Yuri Andriaccio wrote:
> > Disable control files for cgroups-v1, and allow only cgroups-v2.
> >   This should simplify maintaining the code, since cgroups-v1 are deprecated.
> 
> So while I love seeing all this code go away; I very much doubt we can
> pull this off. People might actually be using this.

Quite a bold move indeed. :)

> I think at best we can hide the whole cgroup-v1 thing behind a CONFIG
> and eventually remove once no distro is left using it or something like
> that :/

This however means we will essentially need to maintain 2 versions of
rt.c until v1 is gone? AFAIK v1 rt group implementation is quite a
substantial amount of code. :/

I certainly see your point, just thinking out loud about what options do
we realistically have. Once HCBS is eventually merged, can we consider
v1 RT GROUP feature terminally broken and just point people at v2 if
they report an issue with v1?