linux-kernel - Re: [PATCH 1/5] cpufreq: Use cpumask_copy instead of cpumask

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Date:	Mon, 12 Oct 2015 12:12:56 -0700
From:	Saravana Kannan <skannan@...eaurora.org>
To:	Viresh Kumar <viresh.kumar@...aro.org>
CC:	Rafael Wysocki <rjw@...ysocki.net>, linaro-kernel@...ts.linaro.org,
	linux-pm@...r.kernel.org, open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/5] cpufreq: Use cpumask_copy instead of cpumask_or to
 copy a mask

On 10/11/2015 10:21 AM, Viresh Kumar wrote:
> Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>

The commit text should explain the why you are doing this.

> ---
>   drivers/cpufreq/cpufreq.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index 25c4c15103a0..b32521432db4 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -1221,7 +1221,7 @@ static int cpufreq_online(unsigned int cpu)
>
>   	if (new_policy) {
>   		/* related_cpus should at least include policy->cpus. */
> -		cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);
> +		cpumask_copy(policy->related_cpus, policy->cpus);

Again, why? It actually seems wrong. A 4 core cluster could come up with 
just 2 cores when the policy is added. But the related CPUs would be 4 CPUs.

>   		/* Remember CPUs present at the policy creation time. */
>   		cpumask_and(policy->real_cpus, policy->cpus, cpu_present_mask);
>   	}
>

-Saravana

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