Re: [PATCH] make jiffies wrap 5 min after boot

[Andrew Morton]

Andi Kleen <[e-mail]> wrote:
>
> Anton Blanchard <[e-mail]> 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...)