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From: Andrew Morton <akpm@digeo.com>
To: Andi Kleen <ak@suse.de>
Cc: anton@samba.org, linux-kernel@vger.kernel.org,
	tim@physik3.uni-rostock.de
Subject: Re: [PATCH] make jiffies wrap 5 min after boot
Date: Sat, 15 Feb 2003 22:56:18 -0800	[thread overview]
Message-ID: <20030215225618.538f4c70.akpm@digeo.com> (raw)
In-Reply-To: <p73znowybo5.fsf@amdsimf.suse.de>

Andi Kleen <ak@suse.de> wrote:
>
> Anton Blanchard <anton@samba.org> writes:
> 
> > Hi,
> > 
> > > +#define INITIAL_JIFFIES (0xffffffffUL & (unsigned long)(-300*HZ))
> > 
> > In order to make 64bit arches wrap too, you might want to use -1UL here.
> > Not that jiffies should wrap on a 64bit machine...
> 
> Seems somewhat pointless.
> 
> (2^64-1) / (1000 * 3600 * 24 * 365)
>         ~584942417.35507203243911719939
> 
> I doubt any system ever will have an uptime of > 584 million years
> (assuming HZ=1000) and if jiffies wrap will be the least of their
> problems.
> 

But the point of this patch is to catch jiffy wrap bugs in generic code as
well as in platform-specific code.

Doing it for 64-bit platforms as well will give us just that bit more testing
coverage, and has no cost.  (Well, 8 more bytes of kernel image...)


  reply	other threads:[~2003-02-16  6:45 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <Pine.LNX.4.33L2.0302040935230.6174-100000@dragon.pdx.osdl.net.suse.lists.linux.kernel>
     [not found] ` <Pine.LNX.4.33.0302160232120.7975-100000@gans.physik3.uni-rostock.de.suse.lists.linux.kernel>
     [not found]   ` <20030216020808.GF9833@krispykreme.suse.lists.linux.kernel>
2003-02-16  6:36     ` [PATCH] make jiffies wrap 5 min after boot Andi Kleen
2003-02-16  6:56       ` Andrew Morton [this message]
2003-02-16  7:00         ` Andi Kleen
2003-02-16  8:10         ` Tim Schmielau
2003-02-04 17:37 [PATCH *] use 64 bit jiffies Randy.Dunlap
2003-02-16  1:37 ` [PATCH] make jiffies wrap 5 min after boot Tim Schmielau
2003-02-16  2:08   ` Anton Blanchard
2003-02-16  2:43     ` William Lee Irwin III
2003-02-16  2:50       ` Michael Vergoz
2003-02-16  6:37       ` Robert Love
2003-02-16  7:16         ` Muli Ben-Yehuda
2003-02-16 11:50           ` Falk Hueffner
2003-02-16 12:04             ` William Lee Irwin III

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