Use a per-cpu 'wd_enabled' boolean and a global atomic_t count
of watchdog NMI enabled cpus which is set to '-1' if something
is wrong with the watchdog and it can't be used.
Signed-off-by: David S. Miller <davem@davemloft.net>
Hypervisor versions older than version 1.6.1 cannot handle
leaving the profile counter overflow interrupt chirping
when the system does a soft reset.
So use a reboot notifier to shut off the NMI watchdog.
Signed-off-by: David S. Miller <davem@davemloft.net>