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. Bart.
