From: Len Brown <lenb@kernel.org>
Organization: Intel Open Source Technology Center
To: yi.y.yang@intel.com
Subject: Re: [PATCH 2.6.25-rc3] cpuidle: fix cpuidle time and usage overflow
Date: Wed, 26 Mar 2008 00:46:41 -0400
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References: <1199441414.19185.9.camel@yangyi-dev.bj.intel.com> <1203032921.3897.10.camel@yangyi-dev.bj.intel.com> <1203900372.4954.8.camel@yangyi-dev.bj.intel.com>
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applied

thanks,
-len

On Sunday 24 February 2008, Yi Yang wrote:
> cpuidle C-state sysfs node time and usage are very easy to overflow because
> they are all of unsigned int type, time will overflow within about two hours,
> usage will take longer time to overflow, but they are increasing for ever.
> 
> This patch will convert them to unsigned long long.
> 
> 
> Signed-off-by: Yi Yang <yi.y.yang@intel.com>
> ---
>  drivers/cpuidle/cpuidle.c |    2 +-
>  drivers/cpuidle/sysfs.c   |   10 ++++++++--
>  include/linux/cpuidle.h   |    4 ++--
> 
> --- a/include/linux/cpuidle.h	2008-02-25 02:31:26.000000000 -0500
> +++ b/include/linux/cpuidle.h	2008-02-25 04:30:24.000000000 -0500
> @@ -38,8 +38,8 @@ struct cpuidle_state {
>  	unsigned int	power_usage; /* in mW */
>  	unsigned int	target_residency; /* in US */
>  
> -	unsigned int	usage;
> -	unsigned int	time; /* in US */
> +	unsigned long long	usage;
> +	unsigned long long	time; /* in US */
>  
>  	int (*enter)	(struct cpuidle_device *dev,
>  			 struct cpuidle_state *state);
> --- a/drivers/cpuidle/cpuidle.c	2008-02-25 02:37:14.000000000 -0500
> +++ b/drivers/cpuidle/cpuidle.c	2008-02-25 04:29:19.000000000 -0500
> @@ -67,7 +67,7 @@ static void cpuidle_idle_call(void)
>  	/* enter the state and update stats */
>  	dev->last_residency = target_state->enter(dev, target_state);
>  	dev->last_state = target_state;
> -	target_state->time += dev->last_residency;
> +	target_state->time += (unsigned long long)dev->last_residency;
>  	target_state->usage++;
>  
>  	/* give the governor an opportunity to reflect on the outcome */
> --- a/drivers/cpuidle/sysfs.c	2008-02-25 02:33:14.000000000 -0500
> +++ b/drivers/cpuidle/sysfs.c	2008-02-25 03:10:50.000000000 -0500
> @@ -218,6 +218,12 @@ static ssize_t show_state_##_name(struct
>  	return sprintf(buf, "%u\n", state->_name);\
>  }
>  
> +#define define_show_state_ull_function(_name) \
> +static ssize_t show_state_##_name(struct cpuidle_state *state, char *buf) \
> +{ \
> +	return sprintf(buf, "%llu\n", state->_name);\
> +}
> +
>  #define define_show_state_str_function(_name) \
>  static ssize_t show_state_##_name(struct cpuidle_state *state, char *buf) \
>  { \
> @@ -228,8 +234,8 @@ static ssize_t show_state_##_name(struct
>  
>  define_show_state_function(exit_latency)
>  define_show_state_function(power_usage)
> -define_show_state_function(usage)
> -define_show_state_function(time)
> +define_show_state_ull_function(usage)
> +define_show_state_ull_function(time)
>  define_show_state_str_function(name)
>  define_show_state_str_function(desc)
>  
> 
> 
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