Re: [PATCH v2 5/7] sched/fair: Increase weight bits for avg_vruntime

[Peter Zijlstra <peterz@infradead.org>]

On Mon, Feb 23, 2026 at 12:51:00PM +0100, Peter Zijlstra wrote:

> Let me go build and boot that.

Seems to not explode; had it run a few things and such. Must be good.

> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -679,9 +679,13 @@ static inline void
>  __sum_w_vruntime_add(struct cfs_rq *cfs_rq, struct sched_entity *se)
>  {
>  	unsigned long weight = avg_vruntime_weight(cfs_rq, se->load.weight);
> -	s64 key = entity_key(cfs_rq, se);
> +	s64 w_vruntime, key = entity_key(cfs_rq, se);
>  
> -	cfs_rq->sum_w_vruntime += key * weight;
> +	w_vruntime = key * weight;
> +
> +	WARN_ON_ONCE((w_vruntime >> 63) != (w_vruntime >> 62));
> +
> +	cfs_rq->sum_w_vruntime += w_vruntime;
>  	cfs_rq->sum_weight += weight;
>  }
>