Re: [PATCH v10 8/9] sched/fair: Add latency list

[Peter Zijlstra]

On Fri, Jan 13, 2023 at 03:12:33PM +0100, Vincent Guittot wrote:
> @@ -12552,8 +12634,15 @@ int sched_group_set_latency(struct task_group *tg, s64 latency)
>  
>  	for_each_possible_cpu(i) {
>  		struct sched_entity *se = tg->se[i];
> +		struct rq *rq = cpu_rq(i);
> +		struct rq_flags rf;
> +
> +		rq_lock_irqsave(rq, &rf);
>  
> +		__dequeue_latency(se->cfs_rq, se);
>  		WRITE_ONCE(se->latency_offset, latency);
> +
> +		rq_unlock_irqrestore(rq, &rf);
>  	}

This seems asymmetric; maybe something like:

	queued = __dequeue_latency(..);
	WRITE_ONCE(...);
	if (queued)
		__enqueue_latency(...);

?