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From: Don Zickus on 7 May 2010 17:20
When I combined the nmi_watchdog (hardlockup) and softlockup code, I
also combined the paths the touch_watchdog and touch_nmi_watchdog took.
This may not be the best idea as pointed out by Frederic W., that the
touch_watchdog case probably should not reset the hardlockup count.

Therefore the patch belows falls back to the previous idea of keeping
the touch_nmi_watchdog a superset of the touch_watchdog case.

Signed-off-by: Don Zickus <dzickus(a)redhat.com>
---
kernel/watchdog.c | 7 ++++---
1 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 80a282c..09fb804 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -31,6 +31,7 @@ int watchdog_enabled;
int __read_mostly softlockup_thresh = 60;

static DEFINE_PER_CPU(unsigned long, watchdog_touch_ts);
+static DEFINE_PER_CPU(bool, watchdog_nmi_touch);
static DEFINE_PER_CPU(struct task_struct *, softlockup_watchdog);
static DEFINE_PER_CPU(struct hrtimer, watchdog_hrtimer);
static DEFINE_PER_CPU(bool, softlockup_touch_sync);
@@ -145,6 +146,7 @@ void touch_softlockup_watchdog_sync(void)

void touch_nmi_watchdog(void)
{
+ __get_cpu_var(watchdog_nmi_touch) = true;
touch_softlockup_watchdog();
}
EXPORT_SYMBOL(touch_nmi_watchdog);
@@ -201,10 +203,9 @@ void watchdog_overflow_callback(struct perf_event *event, int nmi,
struct pt_regs *regs)
{
int this_cpu = smp_processor_id();
- unsigned long touch_ts = per_cpu(watchdog_touch_ts, this_cpu);

- if (touch_ts == 0) {
- __touch_watchdog();
+ if (__get_cpu_var(watchdog_nmi_touch) == true) {
+ __get_cpu_var(watchdog_nmi_touch) = false;
return;
}

--
1.7.0.1

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Prev: CPU/mem hotplug: enable CPUs online before local memory online
Next: [PATCH 0/8] lockup detector changes