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Date: Wed, 24 May 2006 15:08:30 -0700
From: Andrew Morton <akpm@osdl.org>
To: Martin Peschke <mp3@de.ibm.com>
Cc: linux-kernel@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [Patch 3/6] statistics infrastructure - prerequisite: timestamp
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Martin Peschke <mp3@de.ibm.com> wrote:
>
> +static inline int nsec_to_timestamp(char *s, unsigned long long t)
> +{
> +	unsigned long nsec_rem = do_div(t, NSEC_PER_SEC);
> +	return sprintf(s, "[%5lu.%06lu]", (unsigned long)t,
> +		       nsec_rem/NSEC_PER_USEC);
> +}

do_div() is actually defined in terms of u64, not unsigned long long. 
Although afaict this will all work OK and all the usual type promotions
will dtrt.

Which begs the question: how _does_ the kernel represent nanoseconds?  The
time-management code is a bit undecided (search for long long in
posix-cpu-timers.c, and for u64 in hrtimers.c).  All a bit confused.

Anwyay.  This function is too big and slow to be inlined..