Re: [PATCH 1/2] sched_ext: Prevent SCX_KICK_WAIT deadlock by serialization

[Tejun Heo]

Hello,

On Mon, Mar 16, 2026 at 10:02:48AM +0000, Christian Loehle wrote:
> @@ -5686,11 +5718,20 @@ static void kick_cpus_irq_workfn(struct irq_work *irq_work)
>  		 * task is picked subsequently. The latter is necessary to break
>  		 * the wait when $cpu is taken by a higher sched class.
>  		 */
> -		if (cpu != cpu_of(this_rq))
> +		if (cpu != this_cpu)
>  			smp_cond_load_acquire(wait_kick_sync, VAL != ksyncs[cpu]);

Given that irq_work is executed at the end of IRQ handling, we can just
reschedule the irq work when the condition is not met (or separate that out
into its own irq_work). That way, I think we can avoid the global lock.

Thanks.

-- 
tejun