Re: [PATCH V2 10/20] cpufreq: Don't traverse list of all policies for adding policy for a cpu

[Saravana Kannan <skannan@codeaurora.org>]

On 02/19/2015 03:32 AM, Viresh Kumar wrote:
> We reach here while adding policy for a CPU and enter into the 'if' block only
> if a policy already exists for the CPU in question. As cpufreq_cpu_data is
> filled once and for all now, we can reuse it to find the relevant policy instead
> of traversing the list of all policies.
>
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---
>   drivers/cpufreq/cpufreq.c | 17 +++++++----------
>   1 file changed, 7 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index f849b2a33d3e..20d5f4590c4b 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -1211,7 +1211,7 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
>   {
>   	unsigned int j, cpu = dev->id;
>   	int ret = -ENOMEM;
> -	struct cpufreq_policy *policy, *tpolicy;
> +	struct cpufreq_policy *policy;
>   	unsigned long flags;
>   	bool recover_policy = cpufreq_suspended;
>
> @@ -1224,16 +1224,13 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
>   		return 0;
>
>   	/* Check if this cpu already has a policy to manage it */
> -	read_lock_irqsave(&cpufreq_driver_lock, flags);
> -	for_each_active_policy(policy, tpolicy) {
> -		if (cpumask_test_cpu(cpu, policy->related_cpus)) {
> -			read_unlock_irqrestore(&cpufreq_driver_lock, flags);
> -			ret = cpufreq_add_policy_cpu(policy, cpu, dev);
> -			up_read(&cpufreq_rwsem);
> -			return ret;
> -		}
> +	policy = per_cpu(cpufreq_cpu_data, cpu);
> +	if (policy && !policy_is_inactive(policy)) {
> +		WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus));
> +		ret = cpufreq_add_policy_cpu(policy, cpu, dev);
> +		up_read(&cpufreq_rwsem);
> +		return ret;
>   	}
> -	read_unlock_irqrestore(&cpufreq_driver_lock, flags);
>
>   	/*
>   	 * Restore the saved policy when doing light-weight init and fall back
>

Acked-by: Saravana Kannan <skannan@codeaurora.org>

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