times(2) sys call bug?

Joakim Tjernlund joakim.tjernlund at transmode.se
Fri Nov 21 21:07:37 EST 2008


On Fri, 2008-11-21 at 20:51 +1100, Paul Mackerras wrote:
> Joakim Tjernlund writes:
> 
> > > +	force_successful_syscall_return();
> > >  	return (long) jiffies_64_to_clock_t(get_jiffies_64());
> > 
> > Why is 64 bits ops used here when you only use 32 bits? 
> 
> If HZ is 1000, jiffies_64_to_clock_t is going to divide jiffies by 10,
> so we need to start with 64 bits in order to get the top few bits
> of a 32-bit result correct.

I see, thanks.

> 
> > BTW, I think time(2) needs this:
> 
> In principle you are correct, but it's only going to matter for a
> little over an hour some time in the year 2106. :)

I know, but I figured it should be fixed to serve as an template for
other similar sys calls(not that I know of any offhand). Perhaps add it
commented?

 Jocke



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