Re: [RFC PATCH 07/13] sched: Add core wide task selection and scheduling.

[Peter Zijlstra]

On Thu, Apr 16, 2020 at 11:39:05AM +0800, Chen Yu wrote:

> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 02495d44870f..ef101a3ef583 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -4477,9 +4477,14 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
>  		return next;
>  	}
>  
> -	prev->sched_class->put_prev_task(rq, prev);
> -	if (!rq->nr_running)
> -		newidle_balance(rq, rf);
> +
> +#ifdef CONFIG_SMP
> +	for_class_range(class, prev->sched_class, &idle_sched_class) {
> +		if (class->balance(rq, prev, rf))
> +			break;
> +	}
> +#endif
> +	put_prev_task(rq, prev);
>  
>  	smt_mask = cpu_smt_mask(cpu);

Instead of duplicating that, how about you put the existing copy in a
function to share? finish_prev_task() perhaps?

Also, can you please make newidle_balance() static again; I forgot doing
that in 6e2df0581f56, which would've made you notice this sooner I
suppose.