Re: [PATCH] sched/fair: Encapsulate set custom slice in a __setparam_fair() function

[Peter Zijlstra <peterz@infradead.org>]

On Fri, Jan 10, 2025 at 03:46:56PM +0100, Vincent Guittot wrote:
> Similarly to dl, create a __setparam_fair() function to set parameters
> related to fair class and move it in the fair.c file.
> 
> No functional changes expected
> 
> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>

Thanks!

> @@ -5050,6 +5053,26 @@ static inline void util_est_update(struct cfs_rq *cfs_rq,
>  	trace_sched_util_est_se_tp(&p->se);
>  }
>  
> +void __setparam_fair(struct task_struct *p, const struct sched_attr *attr)
> +{
> +	struct sched_entity *se = &p->se;
> +	unsigned int util_est;
> +
> +	p->static_prio = NICE_TO_PRIO(attr->sched_nice);
> +	if (attr->sched_runtime) {
> +		se->custom_slice = 1;
> +		se->slice = clamp_t(u64, attr->sched_runtime,
> +				      NSEC_PER_MSEC/10,   /* HZ=1000 * 10 */
> +				      NSEC_PER_MSEC*100); /* HZ=100  / 10 */
> +	} else {
> +		se->custom_slice = 0;
> +		se->slice = sysctl_sched_base_slice;
> +	}
> +
> +
> +}
> +
> +

I've trimmed some of that spurious whitespace.

Also, seeing this function, I'm reminded that I used to have that clamp
conditional on !CAP_SYS_NICE -- is that something we want to put in
again?