Re: [PATCH 09/12] sched_ext: Delegate proxy donor admission to BPF schedulers

[K Prateek Nayak]

Hello Andrea,

On 7/2/2026 10:39 PM, Andrea Righi wrote:
> @@ -7148,7 +7181,8 @@ static void __sched notrace __schedule(int sched_mode)
>  		 * task_is_blocked() will always be false).
>  		 */
>  		try_to_block_task(rq, prev, &prev_state,
> -				  !task_is_blocked(prev));
> +				  !task_is_blocked(prev) ||
> +				  !scx_allow_proxy_exec(prev));
>  		switch_count = &prev->nvcsw;
>  	}
>  
> diff --git a/kernel/sched/ext/ext.c b/kernel/sched/ext/ext.c
> index c48d043dbe58f..8ffbf857acd51 100644
> --- a/kernel/sched/ext/ext.c
> +++ b/kernel/sched/ext/ext.c
> @@ -23,6 +23,14 @@
>  
>  DEFINE_RAW_SPINLOCK(scx_sched_lock);
>  
> +bool scx_allow_proxy_exec(const struct task_struct *p)
> +{
> +	if (!task_on_scx(p))
> +		return true;
> +
> +	return scx_task_sched(p)->ops.flags & SCX_OPS_ENQ_BLOCKED;
> +}
> +

What happens when we switch in a a sched-ext scheduler that
doesn't support proxy?

There would be a bunch proxy donors already preset at the time of the
scheduler loading but I don't see anything in the enable path that
would take care of those tasks by blocking them completely.

Is it handled elsewhere?

-- 
Thanks and Regards,
Prateek