Re: something about jiffies wraparound overflow

[Con Kolivas]

On Tuesday 27 December 2005 19:54, lk wrote:
> As you mentioned the code for comparison:
> > /* code 2*/
> > unsigned long timeout = jiffies + HZ/2;
>
> the code has no problem with jiffies wrapping around
> as long as the values are compared in a right way.
> For a 32 bit platform the counter wraps around only once every 50 day
> when the value of HZ 1000. so if your code is prepared to face this event
> it will work fine.

In 2.6 we actually roll over 5 minutes after starting (the jiffy counter is 
set to about 5 minutes from roll over); that was put in on purpose to pick up 
wraparound bugs easily.

Cheers,
Con
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