Re: [PATCH 1/7] sched/core: uclamp: add CPU clamp groups accounting

[Peter Zijlstra]

On Mon, Apr 09, 2018 at 05:56:09PM +0100, Patrick Bellasi wrote:
> +static inline void init_uclamp(void)

WTH is that inline?

> +{
> +     struct uclamp_cpu *uc_cpu;
> +     int clamp_id;
> +     int cpu;
> +
> +     mutex_init(&uclamp_mutex);
> +
> +     for (clamp_id = 0; clamp_id < UCLAMP_CNT; ++clamp_id) {
> +             /* Init CPU's clamp groups */
> +             for_each_possible_cpu(cpu) {
> +                     uc_cpu = &cpu_rq(cpu)->uclamp[clamp_id];
> +                     memset(uc_cpu, UCLAMP_NONE, sizeof(struct uclamp_cpu));
> +             }
> +     }

Those loops are the wrong way around, this shreds your cache. This is a
slow path so it doesn't much matter, but it is sloppy.

> +}