watchdog: Don't throttle the watchdog

Stephane reported that when the machine locks up, the regular ticks,
which are responsible to resetting the throttle count, stop too.

Hence the NMI watchdog can end up being throttled before it reports on
the locked up state, and we end up being sad..

Cure this by having the watchdog overflow reset its own throttle count.

Reported-by: Stephane Eranian <eranian@google.com>
Tested-by: Stephane Eranian <eranian@google.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1282215916.1926.4696.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2010-08-20 11:49:15 +02:00 committed by Ingo Molnar
parent ede1b42907
commit c6db67cda7

View file

@ -206,6 +206,9 @@ void watchdog_overflow_callback(struct perf_event *event, int nmi,
struct perf_sample_data *data,
struct pt_regs *regs)
{
/* Ensure the watchdog never gets throttled */
event->hw.interrupts = 0;
if (__get_cpu_var(watchdog_nmi_touch) == true) {
__get_cpu_var(watchdog_nmi_touch) = false;
return;