Re: [RFC PATCH] sched: add CONFIG_SCHED_EXT_RT_EXPERIMENTAL to move SCHED_EXT above SCHED_RR/SCHED_FIFO

[Tejun Heo <tj@kernel.org>]

Hello,

On Thu, Apr 16, 2026 at 10:11:16AM +0200, Fredrik Bratberg wrote:
> I understand that this patch undermines the safety aspects taken into the
> design of sched_ext: For example safely returning to the EEVDF scheduler
> if tasks are starved. However, this is a tradeoff which is fine for what I
> am trying to do, and the Kconfig is meant as an "expert" option.

I'm not sure we can include a Kconfig option in the upstream kernel that can
lead to system lockups in everyday scenarios no matter how the option is
marked.

> My goal here is to look into the possibility of creating custom real-time
> policies using sched_ext, where SCHED_EXT tasks could gain priority over
> all other tasks. I am aware that this pushes the boundaries of what
> sched_ext is meant to do, but want to start a discussion on whether this
> could in general be a future feature of sched_ext or not.

In the current form at least, I'm afraid this would have to be carried
outside the tree.

Thanks.

-- 
tejun