linux-kernel - Re: [Update][PATCH 1/2] cpufreq / sched: Pass flags to cpufreq_update

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Date:	Thu, 11 Aug 2016 11:03:47 -0700
From:	Steve Muckle <steve.muckle@...aro.org>
To:	"Rafael J. Wysocki" <rjw@...ysocki.net>
Cc:	Linux PM list <linux-pm@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
	Viresh Kumar <viresh.kumar@...aro.org>,
	Steve Muckle <steve.muckle@...aro.org>,
	Juri Lelli <juri.lelli@....com>, Ingo Molnar <mingo@...nel.org>
Subject: Re: [Update][PATCH 1/2] cpufreq / sched: Pass flags to
 cpufreq_update_util()

On Wed, Aug 10, 2016 at 03:49:07AM +0200, Rafael J. Wysocki wrote:
> Index: linux-pm/kernel/sched/fair.c
> ===================================================================
> --- linux-pm.orig/kernel/sched/fair.c
> +++ linux-pm/kernel/sched/fair.c
> @@ -2875,11 +2875,8 @@ static inline void update_tg_load_avg(st
>  
>  static inline void cfs_rq_util_change(struct cfs_rq *cfs_rq)
>  {
> -	struct rq *rq = rq_of(cfs_rq);
> -	int cpu = cpu_of(rq);
> -
> -	if (cpu == smp_processor_id() && &rq->cfs == cfs_rq) {
> -		unsigned long max = rq->cpu_capacity_orig;
> +	if (&this_rq()->cfs == cfs_rq) {
> +		struct rq *rq = rq_of(cfs_rq);
>  
>  		/*
>  		 * There are a few boundary cases this might miss but it should
> @@ -2897,8 +2894,8 @@ static inline void cfs_rq_util_change(st
>  		 *
>  		 * See cpu_util().
>  		 */
> -		cpufreq_update_util(rq_clock(rq),
> -				    min(cfs_rq->avg.util_avg, max), max);
> +		if (cpu_of(rq) == smp_processor_id())

Isn't this test against smp_processor_id() redundant since
this_rq()->cfs == cfs_rq?

> +			cpufreq_update_util(rq_clock(rq), 0);

All else looked good to me.

thanks,
Steve