Re: [PATCH 1/2] sched/core: Preserve WF_RQ_SELECTED across queued wakeups

[Tejun Heo]

On Fri, Oct 23, 2026 at 02:48:04PM +0000, Kuba Piecuch wrote:
> ENQUEUE_RQ_SELECTED tells a sched_class that ->select_task_rq() was
> called for a task wakeup. sched_ext exposes this flag to BPF schedulers
> as SCX_ENQ_CPU_SELECTED. However, the flag is lost for queued wakeups,
> which a BPF scheduler can opt into with SCX_OPS_ALLOW_QUEUED_WAKEUP.
> This also results in undercounting SCX_EV_SELECT_CPU_FALLBACK events.
>
> Preserve WF_RQ_SELECTED for queued wakeups in the same way WF_MIGRATED
> is. This way, ttwu_activate() receives WF_RQ_SELECTED for queued wakeups
> and passes ENQUEUE_RQ_SELECTED to activate_task().
>
> Fixes: 3539c6411a7c ("sched_ext: Implement SCX_OPS_ALLOW_QUEUED_WAKEUP")
> Signed-off-by: Kuba Piecuch <jpiecuch@xxxxxxxxxx>

Acked-by: Tejun Heo <tj@xxxxxxxxxx>

Thanks.

--
tejun