Re: [powerpc][next-20210621] WARNING at kernel/sched/fair.c:3277 during boot

[Vincent Guittot]

On Wed, 23 Jun 2021 at 14:18, Odin Ugedal <odin@xxxxxxx> wrote:
>
> Hi,
>
> Wouldn't the attached diff below also help when load is removed,
> Vincent? Isn't there a theoretical chance that x_sum ends up at zero
> while x_load ends up as a positive value (without this patch)? Can
> post as a separate patch if it works for Sachin.

In theory it should not because _sum should be always larger or equal
to _avg * divider. Otherwise, it means that we have something wrong
somewhere else

>
>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index bfaa6e1f6067..def48bc2e90b 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -3688,15 +3688,15 @@ update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq)
>
>                 r = removed_load;
>                 sub_positive(&sa->load_avg, r);
> -               sub_positive(&sa->load_sum, r * divider);
> +               sa->load_sum = sa->load_avg * divider;
>
>                 r = removed_util;
>                 sub_positive(&sa->util_avg, r);
> -               sub_positive(&sa->util_sum, r * divider);
> +               sa->util_sum = sa->util_avg * divider;
>
>                 r = removed_runnable;
>                 sub_positive(&sa->runnable_avg, r);
> -               sub_positive(&sa->runnable_sum, r * divider);
> +               sa->runnable_sum = sa->runnable_avg * divider;
>
>                 /*
>                  * removed_runnable is the unweighted version of
> removed_load so we