linux-kernel - Re: [PATCH v3 5/6] sched/fair: Rename scale_load() and scale_load

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Date:	Thu, 28 Apr 2016 11:19:19 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Yuyang Du <yuyang.du@...el.com>
Cc:	mingo@...nel.org, linux-kernel@...r.kernel.org, bsegall@...gle.com,
	pjt@...gle.com, morten.rasmussen@....com,
	vincent.guittot@...aro.org, dietmar.eggemann@....com,
	lizefan@...wei.com, umgwanakikbuti@...il.com
Subject: Re: [PATCH v3 5/6] sched/fair: Rename scale_load() and
 scale_load_down()

On Tue, Apr 05, 2016 at 12:12:30PM +0800, Yuyang Du wrote:
> Rename scale_load() and scale_load_down() to user_to_kernel_load()
> and kernel_to_user_load() respectively, to allow the names to bear
> what they are really about.

> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -189,7 +189,7 @@ static void __update_inv_weight(struct load_weight *lw)
>  	if (likely(lw->inv_weight))
>  		return;
>  
> -	w = scale_load_down(lw->weight);
> +	w = kernel_to_user_load(lw->weight);
>  
>  	if (BITS_PER_LONG > 32 && unlikely(w >= WMULT_CONST))
>  		lw->inv_weight = 1;
> @@ -213,7 +213,7 @@ static void __update_inv_weight(struct load_weight *lw)
>   */
>  static u64 __calc_delta(u64 delta_exec, unsigned long weight, struct load_weight *lw)
>  {
> -	u64 fact = scale_load_down(weight);
> +	u64 fact = kernel_to_user_load(weight);
>  	int shift = WMULT_SHIFT;
>  
>  	__update_inv_weight(lw);
> @@ -6952,10 +6952,11 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
>  	 */
>  	if (busiest->group_type == group_overloaded &&
>  	    local->group_type   == group_overloaded) {
> +		unsigned long min_cpu_load =
> +			kernel_to_user_load(NICE_0_LOAD) * busiest->group_capacity;
>  		load_above_capacity = busiest->sum_nr_running * NICE_0_LOAD;
> -		if (load_above_capacity > scale_load(busiest->group_capacity))
> -			load_above_capacity -=
> -				scale_load(busiest->group_capacity);
> +		if (load_above_capacity > min_cpu_load)
> +			load_above_capacity -= min_cpu_load;
>  		else
>  			load_above_capacity = ~0UL;
>  	}

Except these 3 really are not about user/kernel visible fixed point
ranges _at_all_... :/