Re: [PATCH V2 3/4] cpufreq: Add Kconfig option to enable/disable have_multiple_policies

From: Rafael J. Wysocki
Date: Thu Feb 21 2013 - 18:46:48 EST


On Monday, February 11, 2013 01:20:02 PM Viresh Kumar wrote:
> have_multiple_policies is required by platforms having multiple clock-domains
> for cpus, i.e. supporting multiple policies for cpus. This patch adds in a
> Kconfig option for enabling execution of this code.
>
> Reported-by: Borislav Petkov <bp@xxxxxxxxx>
> Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
> ---
> drivers/cpufreq/Kconfig | 3 +++
> include/linux/cpufreq.h | 4 ++++
> 2 files changed, 7 insertions(+)
>
> diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
> index cbcb21e..e6e6939 100644
> --- a/drivers/cpufreq/Kconfig
> +++ b/drivers/cpufreq/Kconfig
> @@ -23,6 +23,9 @@ config CPU_FREQ_TABLE
> config CPU_FREQ_GOV_COMMON
> bool
>
> +config CPU_FREQ_HAVE_MULTIPLE_POLICIES
> + bool
> +

So I suppose some architectures will select this, right?

What architecture they are?

> config CPU_FREQ_STAT
> tristate "CPU frequency translation statistics"
> select CPU_FREQ_TABLE
> diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
> index c5ac9a5..0d84bfa 100644
> --- a/include/linux/cpufreq.h
> +++ b/include/linux/cpufreq.h
> @@ -107,11 +107,13 @@ struct cpufreq_policy {
> unsigned int policy; /* see above */
> struct cpufreq_governor *governor; /* see below */
> void *governor_data;
> +#ifdef CONFIG_CPU_FREQ_HAVE_MULTIPLE_POLICIES
> /* This should be set by init() of platforms having multiple
> * clock-domains, i.e. supporting multiple policies. With this sysfs
> * directories of governor would be created in cpu/cpu<num>/cpufreq/
> * directory */
> bool have_multiple_policies;
> +#endif

I'm not really sure I like this. ->

> struct work_struct update; /* if update_policy() needs to be
> * called, but you're in IRQ context */
> @@ -142,9 +144,11 @@ static inline bool policy_is_shared(struct cpufreq_policy *policy)
> static inline struct kobject *
> get_governor_parent_kobj(struct cpufreq_policy *policy)
> {
> +#ifdef CONFIG_CPU_FREQ_HAVE_MULTIPLE_POLICIES
> if (policy->have_multiple_policies)
> return &policy->kobj;
> else
> +#endif
> return cpufreq_global_kobject;

-> I wonder why don't you arrange things so that policy->kobj is always
returned, but it points to cpufreq_global_kobject in case there's only one
(i.e. make policy->kobj a pointer)?

> }

Thanks,
Rafael


--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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