[PATCH][V2] cpuidle : use percpu cpuidle in the core code

[Amit Kucheria]

On Mon, Apr 2, 2012 at 3:48 PM, Daniel Lezcano
<daniel.lezcano at linaro.org> wrote:
> The usual cpuidle initialization routines are to register the

s/are to//

> driver, then register a cpuidle device per cpu.
>
> With the device's state count default initialization with the
> driver's state count, the code initialization remains mostly the
> same in the different drivers.

The following is a bit easier to read and captures your point, I think:

By default, most drivers initialize the device state count with the
driver state count.

> We can then add a new function 'cpuidle_register' where we register
> the driver and the devices. These devices can be defined in a global
> static variable in cpuidle.c. We will be able to factor out and
> remove a lot of duplicate lines of code.
>
> As we still have some drivers, with different initialization routines,
> we keep 'cpuidle_register_driver' and 'cpuidle_register_device' as low
> level initialization routines to do some specific operations on the
> cpuidle devices.
>
> Signed-off-by: Daniel Lezcano <daniel.lezcano at linaro.org>
> ---
>  drivers/cpuidle/cpuidle.c |   42 ++++++++++++++++++++++++++++++++++++++++++
>  include/linux/cpuidle.h   |    3 +++
>  2 files changed, 45 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
> index 87411ce..151c55a 100644
> --- a/drivers/cpuidle/cpuidle.c
> +++ b/drivers/cpuidle/cpuidle.c
> @@ -23,6 +23,7 @@
>  #include "cpuidle.h"
>
>  DEFINE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
> +DEFINE_PER_CPU(struct cpuidle_device, cpuidle_device);
>
>  DEFINE_MUTEX(cpuidle_lock);
>  LIST_HEAD(cpuidle_detected_devices);
> @@ -419,6 +420,47 @@ int cpuidle_register_device(struct cpuidle_device *dev)
>
>  EXPORT_SYMBOL_GPL(cpuidle_register_device);
>
> +/*
> + * cpuidle_register : register cpuidle driver and devices
> + * Note this function must be called after smp_init.
> + * @drv : the cpuidle driver
> + * Returns 0 on success, < 0 otherwise
> + */
> +int cpuidle_register(struct cpuidle_driver *drv)
> +{
> +       int ret, cpu, i;
> +       struct cpuidle_device *dev;
> +
> +       ret = cpuidle_register_driver(drv);
> +       if (ret)
> +               return ret;
> +
> +       for_each_online_cpu(cpu) {
> +               dev = &per_cpu(cpuidle_device, cpu);
> +               dev->cpu = cpu;
> +
> +               ret = cpuidle_register_device(dev);
> +               if (ret)
> +                       goto out_unregister;
> +       }
> +
> +out:
> +       return ret;
> +
> +out_unregister:
> +       for_each_online_cpu(i) {
> +               if (i == cpu)
> +                       break;
> +               dev = &per_cpu(cpuidle_device, cpu);
> +               cpuidle_unregister_device(dev);
> +       }
> +
> +       cpuidle_unregister_driver(drv);
> +
> +       goto out;
> +}
> +EXPORT_SYMBOL_GPL(cpuidle_register);
> +
>  /**
>  * cpuidle_unregister_device - unregisters a CPU's idle PM feature
>  * @dev: the cpu
> diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
> index 6c26a3d..3475294 100644
> --- a/include/linux/cpuidle.h
> +++ b/include/linux/cpuidle.h
> @@ -135,6 +135,7 @@ struct cpuidle_driver {
>  #ifdef CONFIG_CPU_IDLE
>  extern void disable_cpuidle(void);
>  extern int cpuidle_idle_call(void);
> +extern int cpuidle_register(struct cpuidle_driver *drv);
>  extern int cpuidle_register_driver(struct cpuidle_driver *drv);
>  struct cpuidle_driver *cpuidle_get_driver(void);
>  extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
> @@ -154,6 +155,8 @@ extern int cpuidle_play_dead(void);
>  #else
>  static inline void disable_cpuidle(void) { }
>  static inline int cpuidle_idle_call(void) { return -ENODEV; }
> +static inline int cpuidle_register(struct cpuidle_driver *drv)
> +{return -ENODEV; }
>  static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
>  {return -ENODEV; }
>  static inline struct cpuidle_driver *cpuidle_get_driver(void) {return NULL; }
> --
> 1.7.5.4
>
>
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