Re: [RFC PATCH sched_ext/for-7.4 0/5] sched_ext: Make ops.cpu_acquire/release() reliable

[Tejun Heo]

Hello, Kuba.

On Mon, Oct 19, 2026 at 02:48:05PM +0000, Kuba Piecuch wrote:
> Tejun, Peter, would a hook like this be acceptable? The core.c
> footprint is one line, it's a static branch when SCX isn't enabled, and
> the out-of-line call only happens when the pick goes to a class above
> SCX. If you're OK with it, I'd send the IMMED fix first, separately
> (Fixes: 98d709cba319 ("sched_ext: Implement SCX_ENQ_IMMED")), and
> rebase v2 of this series on top of it.

I don't really see a lot of utility in ops.cpu_acquire/release(). As it
currently stands, it doesn't add anything that can't be covered by IMMED,
and given how asynchronous the events are, I'm not sure an edge-triggered
view of CPU availability is particularly useful. IMMED works because it's
something the kernel can check and enforce. If there are holes in it,
let's plug them, but I don't think the holes justify keeping or updating
ops.cpu_acquire/release().

Can you please send the IMMED fixes separately?

Thanks.

--
tejun