linux-kernel - Re: [PATCH] cpufreq: powernv: Add support of frequency domain

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Date:   Thu, 14 Dec 2017 10:12:39 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Abhishek Goel <huntbag@...ux.vnet.ibm.com>, ego@...ux.vnet.ibm.com
Cc:     rjw@...ysocki.net, benh@...nel.crashing.org, paulus@...ba.org,
        mpe@...erman.id.au, linux-pm@...r.kernel.org,
        linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] cpufreq: powernv: Add support of frequency domain

+ Gautham,

@Gautham: Can you please help reviewing this one ?

On 13-12-17, 13:49, Abhishek Goel wrote:
> @@ -693,6 +746,8 @@ static int powernv_cpufreq_target_index(struct cpufreq_policy *policy,
>  {
>  	struct powernv_smp_call_data freq_data;
>  	unsigned int cur_msec, gpstate_idx;
> +	cpumask_t temp;
> +	u32 cpu;
>  	struct global_pstate_info *gpstates = policy->driver_data;
>  
>  	if (unlikely(rebooting) && new_index != get_nominal_index())
> @@ -761,24 +816,48 @@ static int powernv_cpufreq_target_index(struct cpufreq_policy *policy,
>  	spin_unlock(&gpstates->gpstate_lock);
>  
>  	/*
> -	 * Use smp_call_function to send IPI and execute the
> -	 * mtspr on target CPU.  We could do that without IPI
> -	 * if current CPU is within policy->cpus (core)
> +	 * Use smp_call_function to send IPI and execute the mtspr on CPU.
> +	 * This needs to be done on every core of the policy

Why on each CPU ?

>  	 */
> -	smp_call_function_any(policy->cpus, set_pstate, &freq_data, 1);
> +	cpumask_copy(&temp, policy->cpus);
> +
> +	while (!cpumask_empty(&temp)) {
> +		cpu = cpumask_first(&temp);
> +		smp_call_function_any(cpu_sibling_mask(cpu),
> +					set_pstate, &freq_data, 1);
> +		cpumask_andnot(&temp, &temp, cpu_sibling_mask(cpu));
> +	}
> +
>  	return 0;
>  }

-- 
viresh