Re: [PATCH v2 sched_ext/for-7.1] sched_ext: Invalidate dispatch decisions on CPU affinity changes

Andrea Righi
2026-05-04T21:58:34Z

On Mon, May 04, 2026 at 11:24:57AM -1000, Tejun Heo wrote:
> On Mon, May 04, 2026 at 08:00:50AM +0000, Kuba Piecuch wrote:
> > Random thought: If exposing qseq values to BPF directly is undesirable, then
> > perhaps a less objectionable approach would be to expose them as opaque
> > cookie/token values? Same semantics, but fewer SCX internals leaking to BPF.
>
> Yeah, cookie sounds fine to me and let's clearly note that this is for
> schedulers that don't implement properly synchronized dequeue.

I also like the idea of exposing cookies and extending scx_bpf_dispatch_cancel()
to support direct dispatches, it it doesn't introduce too much complexity (it
shouldn't be too painful).

Cheng-Yang, just to make sure we're not doing the work twice, are you planning
to work on this?

Thanks,
-Andrea