Re: [RFC][PATCH 1/5] sched/fair: Fix select_idle_cpu()s cost accounting

[Qais Yousef]

On 01/08/21 10:27, Mel Gorman wrote:
>       for_each_cpu_wrap(cpu, cpus, target) {
> -             if (available_idle_cpu(cpu) || sched_idle_cpu(cpu))
> +             if (available_idle_cpu(cpu) || sched_idle_cpu(cpu)) {
> +                     /* Adjust cost of a successful scan */
> +                     loops <<= 2;
> +
>                       break;
> +             }
>  
> -             if (loops >= nr) {
> +             if (++loops >= nr) {
>                       cpu = -1;
>                       break;
>               }
> -             loops++;

Random (out of the blue) comment.

Now this will increment loops before the comparison/break. ie: we're
effectively doing one iteration less IIRC. Should loops be initialized to
0 instead of 1?

Thanks

--
Qais Yousef