On Wed, 30 Jan 2013 22:19:16 +0100, Sebastian Andrzej Siewior wrote:
> This patch adds an interface to cpuidle in order to retrieve the current
> idle state of a given CPU. Zero means the CPU is not in an idle state. Either
> because a cpuidle driver is not available or because the CPU is busy
> executing code. Values greater than zero the CPU indicate that the CPU
> is in some kind of idle state. The larger the value, the deeper the idle
> state.
>
> Signed-off-by: Sebastian Andrzej Siewior <bige...@linutronix.de>
> ---
> drivers/cpuidle/cpuidle.c | 13 ++++++++++++-
> include/linux/cpuidle.h | 2 ++
> 2 files changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
> index e1f6860..3594e0c 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);
> +static DEFINE_PER_CPU(unsigned int, cpu_state);
What about making it 'int' as cpuidle_get_state() returns int type?
>
> DEFINE_MUTEX(cpuidle_lock);
> LIST_HEAD(cpuidle_detected_devices);
> @@ -40,13 +41,23 @@ void disable_cpuidle(void)
> off = 1;
> }
>
> +int cpuidle_get_state(int cpu)
> +{
> + return per_cpu(cpu_state, cpu);
> +}
> +
> static int __cpuidle_register_device(struct cpuidle_device *dev);
>
> static inline int cpuidle_enter(struct cpuidle_device *dev,
> struct cpuidle_driver *drv, int index)
> {
> struct cpuidle_state *target_state = &drv->states[index];
> - return target_state->enter(dev, drv, index);
> + int ret;
> +
> + per_cpu(cpu_state, smp_processor_id()) = index + 1;
> + ret = target_state->enter(dev, drv, index);
> + per_cpu(cpu_state, smp_processor_id()) = 0;
Maybe we can use local variable 'cpu' for this duplicated
smp_processor_id() call as it's never executed on another cpu in
between?
Thanks,
Namhyung
> + return ret;
> }
>
> static inline int cpuidle_enter_tk(struct cpuidle_device *dev,
> diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
> index 24cd1037..256baeb 100644
> --- a/include/linux/cpuidle.h
> +++ b/include/linux/cpuidle.h
> @@ -155,6 +155,7 @@ extern int cpuidle_wrap_enter(struct cpuidle_device *dev,
> struct cpuidle_driver *drv, int index,
> int (*enter)(struct cpuidle_device *dev,
> struct cpuidle_driver *drv, int index));
> +extern int cpuidle_get_state(int cpu);
> extern int cpuidle_play_dead(void);
>
> extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device
> *dev);
> @@ -186,6 +187,7 @@ static inline int cpuidle_wrap_enter(struct
> cpuidle_device *dev,
> int (*enter)(struct cpuidle_device *dev,
> struct cpuidle_driver *drv, int index))
> { return -ENODEV; }
> +static inline int cpuidle_get_state(int cpu) {return 0; }
> static inline int cpuidle_play_dead(void) {return -ENODEV; }
> #endif
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