Re: [PATCH 2/7] sched/fair: prepare throttle path for task based throttle

[Florian Bezdeka <florian.bezdeka@siemens.com>]

On Tue, 2025-05-20 at 18:41 +0800, Aaron Lu wrote:
> @@ -6744,6 +6805,7 @@ static bool check_cfs_rq_runtime(struct cfs_rq *cfs_rq) { return false; }
>  static void check_enqueue_throttle(struct cfs_rq *cfs_rq) {}
>  static inline void sync_throttle(struct task_group *tg, int cpu) {}
>  static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq) {}
> +static void task_throttle_setup_work(struct task_struct *p) {}
>  
>  static inline int cfs_rq_throttled(struct cfs_rq *cfs_rq)
>  {
> @@ -8851,6 +8913,7 @@ static struct task_struct *pick_task_fair(struct rq *rq)
>  {
>  	struct sched_entity *se;
>  	struct cfs_rq *cfs_rq;
> +	struct task_struct *p;
>  
>  again:
>  	cfs_rq = &rq->cfs;
> @@ -8871,7 +8934,14 @@ static struct task_struct *pick_task_fair(struct rq *rq)
>  		cfs_rq = group_cfs_rq(se);
>  	} while (cfs_rq);
>  
> -	return task_of(se);
> +	p = task_of(se);
> +	if (throttled_hierarchy(cfs_rq_of(se))) {
> +		/* Shuold not happen for now */

Typo: s/Shuold/Should

Btw: Is there a trace point in place when throttling/unthrottling
happens? Would be nice to see that in a trace, but might be that I
missed those events in my configuration up to now.

> +		WARN_ON_ONCE(1);
> +		task_throttle_setup_work(p);
> +	}
> +
> +	return p;
>  }