Re: [PATCH] cpuidle: move field disable from per-driver to per-cpu

[Deepthi Dharwar <deepthi@linux.vnet.ibm.com>]

On 06/14/2012 08:22 AM, ShuoX Liu wrote:

> From: ShuoX Liu <shuox.liu@intel.com>
> 
> Andrew J.Schorr raises a question. When he changes the disable setting
> on a single CPU, it affects all the other CPUs. Basically, currently,
> the disable field is per-driver instead of per-cpu. All the C states of
> the same driver are shared by all CPU in the same machine.
> 
> Below patch changes field disable to per-cpu, so we could set this
> separately for each cpu.
> 


This would help us have asymmetric C-states on cpus.

> Reported-by: Andrew J.Schorr <aschorr@telemetry-investments.com>
> Reviewed-by: Yanmin Zhang <yanmin_zhang@intel.com>
> Signed-off-by: ShuoX Liu <shuox.liu@intel.com>


Acked-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>

> ---
>  drivers/cpuidle/cpuidle.c        |    1 -
>  drivers/cpuidle/governors/menu.c |    5 +++--
>  drivers/cpuidle/sysfs.c          |   21 ++++++++++++---------
>  include/linux/cpuidle.h          |    2 +-
>  4 files changed, 16 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
> index d90519c..04e4b76 100644
> --- a/drivers/cpuidle/cpuidle.c
> +++ b/drivers/cpuidle/cpuidle.c
> @@ -265,7 +265,6 @@ static void poll_idle_init(struct cpuidle_driver *drv)
>  	state->power_usage = -1;
>  	state->flags = 0;
>  	state->enter = poll_idle;
> -	state->disable = 0;
>  }
>  #else
>  static void poll_idle_init(struct cpuidle_driver *drv) {}
> diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
> index 0633575..8391d93 100644
> --- a/drivers/cpuidle/governors/menu.c
> +++ b/drivers/cpuidle/governors/menu.c
> @@ -281,7 +281,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
>  	 * unless the timer is happening really really soon.
>  	 */
>  	if (data->expected_us > 5 &&
> -		drv->states[CPUIDLE_DRIVER_STATE_START].disable == 0)
> +		dev->states_usage[CPUIDLE_DRIVER_STATE_START].disable == 0)
>  		data->last_state_idx = CPUIDLE_DRIVER_STATE_START;
> 
>  	/*
> @@ -290,8 +290,9 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
>  	 */
>  	for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++) {
>  		struct cpuidle_state *s = &drv->states[i];
> +		struct cpuidle_state_usage *su = &dev->states_usage[i];
> 
> -		if (s->disable)
> +		if (su->disable)
>  			continue;
>  		if (s->target_residency > data->predicted_us)
>  			continue;
> diff --git a/drivers/cpuidle/sysfs.c b/drivers/cpuidle/sysfs.c
> index 88032b4..5f809e3 100644
> --- a/drivers/cpuidle/sysfs.c
> +++ b/drivers/cpuidle/sysfs.c
> @@ -217,7 +217,8 @@ struct cpuidle_state_attr {
>  	struct attribute attr;
>  	ssize_t (*show)(struct cpuidle_state *, \
>  					struct cpuidle_state_usage *, char *);
> -	ssize_t (*store)(struct cpuidle_state *, const char *, size_t);
> +	ssize_t (*store)(struct cpuidle_state *, \
> +			struct cpuidle_state_usage *, const char *, size_t);
>  };
> 
>  #define define_one_state_ro(_name, show) \
> @@ -233,21 +234,22 @@ static ssize_t show_state_##_name(struct cpuidle_state *state, \
>  	return sprintf(buf, "%u\n", state->_name);\
>  }
> 
> -#define define_store_state_function(_name) \
> +#define define_store_state_ull_function(_name) \
>  static ssize_t store_state_##_name(struct cpuidle_state *state, \
> +		struct cpuidle_state_usage *state_usage, \
>  		const char *buf, size_t size) \
>  { \
> -	long value; \
> +	unsigned long long value; \
>  	int err; \
>  	if (!capable(CAP_SYS_ADMIN)) \
>  		return -EPERM; \
> -	err = kstrtol(buf, 0, &value); \
> +	err = kstrtoull(buf, 0, &value); \
>  	if (err) \
>  		return err; \
>  	if (value) \
> -		state->disable = 1; \
> +		state_usage->_name = 1; \
>  	else \
> -		state->disable = 0; \
> +		state_usage->_name = 0; \
>  	return size; \
>  }
> 
> @@ -273,8 +275,8 @@ define_show_state_ull_function(usage)
>  define_show_state_ull_function(time)
>  define_show_state_str_function(name)
>  define_show_state_str_function(desc)
> -define_show_state_function(disable)
> -define_store_state_function(disable)
> +define_show_state_ull_function(disable)
> +define_store_state_ull_function(disable)
> 
>  define_one_state_ro(name, show_state_name);
>  define_one_state_ro(desc, show_state_desc);
> @@ -318,10 +320,11 @@ static ssize_t cpuidle_state_store(struct kobject *kobj,
>  {
>  	int ret = -EIO;
>  	struct cpuidle_state *state = kobj_to_state(kobj);
> +	struct cpuidle_state_usage *state_usage = kobj_to_state_usage(kobj);
>  	struct cpuidle_state_attr *cattr = attr_to_stateattr(attr);
> 
>  	if (cattr->store)
> -		ret = cattr->store(state, buf, size);
> +		ret = cattr->store(state, state_usage, buf, size);
> 
>  	return ret;
>  }
> diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
> index 6c26a3d..8570012 100644
> --- a/include/linux/cpuidle.h
> +++ b/include/linux/cpuidle.h
> @@ -34,6 +34,7 @@ struct cpuidle_driver;
>  struct cpuidle_state_usage {
>  	void		*driver_data;
> 
> +	unsigned long long	disable;
>  	unsigned long long	usage;
>  	unsigned long long	time; /* in US */
>  };
> @@ -46,7 +47,6 @@ struct cpuidle_state {
>  	unsigned int	exit_latency; /* in US */
>  	int		power_usage; /* in mW */
>  	unsigned int	target_residency; /* in US */
> -	unsigned int    disable;
> 
>  	int (*enter)	(struct cpuidle_device *dev,
>  			struct cpuidle_driver *drv,