Re: [PATCH v3 1/2] sched/numa: Drive NUMA task tick from execution context

[Chen, Yu C]

On 9/8/2026 4:35 PM, Peter Zijlstra wrote:
> What about something like so?

Thanks Peter for taking a look at this. I think this version achieves 
better decoupling
since the logic is added per scheduling class, rather than inserting 
random hooks into
the core scheduler.

> -static void task_tick_scx(struct rq *rq, struct task_struct *curr, int queued)
> +static void task_tick_scx(struct rq *rq, int queued)
>   {
> +	struct task_struct *curr = rq->donor;

struct task_struct *donor = rq->donor

>   	struct scx_sched *sch = scx_task_sched(curr);
>   
> +	if (donor->sched_class != &ext_sched_class)
> +		return;
> +
>   	update_curr_scx(rq);
>   
>   	/*

[ ... ]

> -static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued)
> +static void task_tick_fair(struct rq *rq, int queued)
>   {
> -	struct sched_entity *se = &curr->se;
> +	struct task_struct *curr = rq->curr, *donor = rq->donor;
>   
> -	if (se->on_rq) {
> -		unsigned long weight = NICE_0_LOAD;
> -		struct cfs_rq *cfs_rq;
> +	if (donor->sched_class == &fair_sched_class) {
> +		struct sched_entity *se = &donor->se;
>   
> -		for_each_sched_entity(se) {
> -			cfs_rq = cfs_rq_of(se);
> -			entity_tick(cfs_rq, se, queued);
> +		if (se->on_rq) {
> +			unsigned long weight = NICE_0_LOAD;
> +			struct cfs_rq *cfs_rq;
>   
> -			weight = __calc_prop_weight(cfs_rq, se, weight);
> +			for_each_sched_entity(se) {
> +				cfs_rq = cfs_rq_of(se);
> +				entity_tick(cfs_rq, se, queued);
> +
> +				weight = __calc_prop_weight(cfs_rq, se, weight);
> +			}
> +
> +			se = &donor->se;
> +			reweight_eevdf(cfs_rq, se, weight, se->on_rq);
>   		}
>   
> -		se = &curr->se;
> -		reweight_eevdf(cfs_rq, se, weight, se->on_rq);
> +		if (queued)
> +			return;
> +
> +		update_misfit_status(donor, rq);
> +		check_update_overutilized_status(task_rq(donor));
> +
> +		task_tick_core(rq, donor);
>   	}
>   
> -	if (queued)
> -		return;

The queued check might still be needed: if donor is not a fair task, we 
still
want to skip the numa balancing/sched_cache for hrtick event?
thanks,
Chenyu