Re: [PATCH v4 03/16] sched/core: uclamp: add CPU's clamp groups accounting

[Peter Zijlstra]

On Tue, Aug 28, 2018 at 02:53:11PM +0100, Patrick Bellasi wrote:
> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
> index 72df2dc779bc..513608ae4908 100644
> --- a/kernel/sched/sched.h
> +++ b/kernel/sched/sched.h
> @@ -764,6 +764,50 @@ extern void rto_push_irq_work_func(struct irq_work *work);
>  #endif
>  #endif /* CONFIG_SMP */
>  
> +#ifdef CONFIG_UCLAMP_TASK
> +/**
> + * struct uclamp_group - Utilization clamp Group
> + * @value: utilization clamp value for tasks on this clamp group
> + * @tasks: number of RUNNABLE tasks on this clamp group
> + *
> + * Keep track of how many tasks are RUNNABLE for a given utilization
> + * clamp value.
> + */
> +struct uclamp_group {
> +	int value;
> +	int tasks;
> +};

We could use bit fields again to compress in 10:22 bits I suppose. 4M
tasks is quite a lot to have runnable on a single CPU ;-)