Re: [RFC PATCH 8/9] sched/rt: Remove support for cgroups-v1

[Juri Lelli <juri.lelli@redhat.com>]

Hello,

On 05/06/25 09:14, Yuri Andriaccio wrote:
> Disable control files for cgroups-v1, and allow only cgroups-v2. This should
> simplify maintaining the code, also because cgroups-v1 is deprecated.

I wonder if the change above and what below need to be split in separate
patches. They look orthogonal and we would have a single separate patch
disabling v1 support which is probably desirable.

> Set the default rt-cgroups runtime to zero, otherwise a cgroup-v1 kernel will
> not be able to start SCHED_DEADLINE tasks.
> 
> Allow zeroing the runtime of the root control group. This runtime only affects
> the available bandwidth of the rt-cgroup hierarchy but not the SCHED_FIFO /
> SCHED_RR tasks on the global runqueue.
> 
> Notes:
> Disabling the root control group bandwidth should not cause any side effect, as
> SCHED_FIFO / SCHED_RR tasks do not depend on it since the introduction of
> fair_servers.

Also, what summarized above needs to be well documented in the kernel
docs, as I am pretty sure it will surprise people (actually surprised
even myself while playing with the set :).

Thanks,
Juri