On Tue, Nov 15, 2016 at 02:50:17PM +0000, Bart Van Assche wrote:
> On Tue, 2016-11-15 at 10:18 +0100, Johannes Thumshirn wrote:
> > On Tue, Nov 08, 2016 at 03:04:43PM +0000, Bart Van Assche wrote:
> > > I think the above code will miscalculate seconds_since_last_reset
> > > if
> > > 'jiffies' wraps around after an lport has been created and before
> > > seconds_since_last_reset is computed. Shouldn't
> > > seconds_since_last_reset
> > > be computed as follows?
> > >
> > > fc_stats->seconds_since_last_reset = (jiffies - boot_time) /
> > > HZ;
> >
> > But what happens when jiffies - boot_time becomes negative? Then we
> > reintroduce the bug again and have 'fcoeadm -s' show weird values.
>
> Hello Johannes,
>
> If your concern is about 'jiffies' wrapping around on 32-bit systems
> then you should use get_jiffies_64(). get_jiffies_64() - boot_time
> can't become negative. It namely takes several million years before a
> 64-bit HZ counter wraps around.
You're right. I'll respin using get_jiffies_64() and resent once it is tested.
Byte,
Johannes
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