From mboxrd@z Thu Jan  1 00:00:00 1970
From: William Lee Irwin III <wli@holomorphy.com>
Subject: Re: MSEC_TO_JIFFIES is messed up...
Date: Wed, 12 May 2004 13:38:29 -0700
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Cc: Ingo Molnar <mingo@elte.hu>, davidel@xmailserver.org, jgarzik@pobox.com,
        greg@kroah.com, linux-kernel@vger.kernel.org, netdev@oss.sgi.com
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To: Andrew Morton <akpm@osdl.org>
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On Wed, May 12, 2004 at 01:20:50PM -0700, Andrew Morton wrote:
> How about we do:
> #if HZ=1000
> #define	MSEC_TO_JIFFIES(msec) (msec)
> #define JIFFIES_TO_MESC(jiffies) (jiffies)
> #elif HZ=100
> #define	MSEC_TO_JIFFIES(msec) (msec * 10)
> #define JIFFIES_TO_MESC(jiffies) (jiffies / 10)
> #else
> #define	MSEC_TO_JIFFIES(msec) ((HZ * (msec) + 999) / 1000)
> #define	JIFFIES_TO_MSEC(jiffies) ...
> #endif
> in some kernel-wide header then kill off all the private implementations?

How about this?

#if HZ <= 1000 && !(1000 % HZ)
#define MSEC_TO_JIFFIES(m)	((1000/HZ)*(m))
#define JIFFIES_TO_MSEC(j)	((j)/(1000/HZ))
#elif HZ > 1000 && !(HZ % 1000)
#define MSEC_TO_JIFFIES(m)	((m)/(HZ/1000))
#define JIFFIES_TO_MSEC(j)	((HZ/1000)*(j))
#else
#define MSEC_TO_JIFFIES(m)	((HZ*(m) + 999)/1000)
#define JIFFIES_TO_MSEC(j)	((1000*(j) + HZ - 1)/HZ)
#endif


-- wli