Re: [RFC][PATCH 1/4] add jiffies_to_nsecs() helper and fix up sizeof usecs

From: Dave Hansen
Date: Thu Jul 14 2005 - 15:58:44 EST


On Thu, 2005-07-14 at 13:28 -0700, Nishanth Aravamudan wrote:
> +static inline u64 jiffies_to_nsecs(const unsigned long j)
> +{
> +#if HZ <= NSEC_PER_SEC && !(NSEC_PER_SEC % HZ)
> + return (NSEC_PER_SEC / HZ) * (u64)j;
> +#elif HZ > NSEC_PER_SEC && !(HZ % NSEC_PER_SEC)
> + return ((u64)j + (HZ / NSEC_PER_SEC) - 1)/(HZ / NSEC_PER_SEC);
> +#else
> + return ((u64)j * NSEC_PER_SEC) / HZ;
> +#endif
> +}

That might look a little better something like:

static inline u64 jiffies_to_nsecs(const unsigned long __j)
{
u64 j = __j;

if (HZ <= NSEC_PER_SEC && !(NSEC_PER_SEC % HZ))
return (NSEC_PER_SEC / HZ) * j;
else if (HZ > NSEC_PER_SEC && !(HZ % NSEC_PER_SEC))
return (j + (HZ / NSEC_PER_SEC) - 1)/(HZ / NSEC_PER_SEC);
else
return (j * NSEC_PER_SEC) / HZ;
}

Compilers are smart :)

-- Dave

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