Re: [PATCHSET v5 sched_ext/for-7.3] sched_ext: Capability-based CPU delegation for sub-schedulers

[Tejun Heo]

Hello, Andrea.

On Tue, Jul 14, 2026 at 09:10:13AM +0200, Andrea Righi wrote:
> I went through the series and tested the resulting kernel under virtme-ng. I
> couldn't trigger any crashes, lockups, or warnings, and I don't see any issues
> that should block applying this.
>
> As I mentioned, one possible follow-up optimization would be to introduce a
> "scx_has_sub_scheds" static key, indicating whether any sub-scheduler is
> attached. This could preserve the current fast paths for the common case of a
> single root-only scheduler, avoiding the small potential overhead of
> sub-scheduler-specific hierarchy walks and capability checks. And it could also
> enable additional optimizations in the future.

Yeah, gating the sub-sched-only paths behind a static key while no
sub-scheduler is attached is on the todo list. Will follow up with
incremental patches.

> For the series:
>
> Reviewed-by: Andrea Righi <arighi@xxxxxxxxxx>

Thanks a lot for the review and testing.

--
tejun