Re: [PATCH v2] procfs: do not confuse jiffies with cputime64_t

From: Michal Hocko
Date: Mon Dec 12 2011 - 07:43:36 EST


On Mon 12-12-11 12:51:19, Andreas Schwab wrote:
> get_{idle,iowait}_time are supposed to return cputime64_t values, not
> jiffies. Add usecs_to_cputime64 for this.

OK, this looks much better than doing an artificial
us -> ns -> jiffies -> cputime64

Could you also add usecs_to_cputime64 for s390 so that all this is
consistent?

This should cover all architectures AFAICS.

Thanks

>
> Signed-off-by: Andreas Schwab <schwab@xxxxxxxxxxxxxx>

Acked-by: Michal Hocko <mhocko@xxxxxxx>

> ---
> arch/ia64/include/asm/cputime.h | 1 +
> arch/powerpc/include/asm/cputime.h | 2 ++
> fs/proc/stat.c | 4 ++--
> include/asm-generic/cputime.h | 1 +
> 4 files changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/arch/ia64/include/asm/cputime.h b/arch/ia64/include/asm/cputime.h
> index 6073b18..5a274af 100644
> --- a/arch/ia64/include/asm/cputime.h
> +++ b/arch/ia64/include/asm/cputime.h
> @@ -60,6 +60,7 @@ typedef u64 cputime64_t;
> */
> #define cputime_to_usecs(__ct) ((__ct) / NSEC_PER_USEC)
> #define usecs_to_cputime(__usecs) ((__usecs) * NSEC_PER_USEC)
> +#define usecs_to_cputime64(__usecs) usecs_to_cputime(__usecs)
>
> /*
> * Convert cputime <-> seconds
> diff --git a/arch/powerpc/include/asm/cputime.h b/arch/powerpc/include/asm/cputime.h
> index 33a3580..fa3f921 100644
> --- a/arch/powerpc/include/asm/cputime.h
> +++ b/arch/powerpc/include/asm/cputime.h
> @@ -150,6 +150,8 @@ static inline cputime_t usecs_to_cputime(const unsigned long us)
> return ct;
> }
>
> +#define usecs_to_cputime64(us) usecs_to_cputime(us)
> +
> /*
> * Convert cputime <-> seconds
> */
> diff --git a/fs/proc/stat.c b/fs/proc/stat.c
> index 2a30d67..0855e6f 100644
> --- a/fs/proc/stat.c
> +++ b/fs/proc/stat.c
> @@ -32,7 +32,7 @@ static cputime64_t get_idle_time(int cpu)
> idle = kstat_cpu(cpu).cpustat.idle;
> idle = cputime64_add(idle, arch_idle_time(cpu));
> } else
> - idle = nsecs_to_jiffies64(1000 * idle_time);
> + idle = usecs_to_cputime64(idle_time);
>
> return idle;
> }
> @@ -46,7 +46,7 @@ static cputime64_t get_iowait_time(int cpu)
> /* !NO_HZ so we can rely on cpustat.iowait */
> iowait = kstat_cpu(cpu).cpustat.iowait;
> else
> - iowait = nsecs_to_jiffies64(1000 * iowait_time);
> + iowait = usecs_to_cputime64(iowait_time);
>
> return iowait;
> }
> diff --git a/include/asm-generic/cputime.h b/include/asm-generic/cputime.h
> index 62ce682..12a1764 100644
> --- a/include/asm-generic/cputime.h
> +++ b/include/asm-generic/cputime.h
> @@ -40,6 +40,7 @@ typedef u64 cputime64_t;
> */
> #define cputime_to_usecs(__ct) jiffies_to_usecs(__ct)
> #define usecs_to_cputime(__msecs) usecs_to_jiffies(__msecs)
> +#define usecs_to_cputime64(__msecs) nsecs_to_jiffies64((__msecs) * 1000)
>
> /*
> * Convert cputime to seconds and back.
> --
> 1.7.8
>
>
> --
> Andreas Schwab, schwab@xxxxxxxxxxxxxx
> GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
> "And now for something completely different."
> --
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--
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9
Czech Republic
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