From: Thomas Gleixner <[EMAIL PROTECTED]>
The NMI watchdog implementation assumes that the local APIC timer
interrupt is happening. This assumption is not longer true when high
resolution timers and dynamic ticks come into play, as they may switch
off the local APIC timer completely. Take the PIT/HPET interrupts into
account too, to avoid false positives.
Signed-off-by: Thomas Gleixner <[EMAIL PROTECTED]>
Signed-off-by: Ingo Molnar <[EMAIL PROTECTED]>
Cc: Andi Kleen <[EMAIL PROTECTED]>
Cc: Zachary Amsden <[EMAIL PROTECTED]>
Cc: "Eric W. Biederman" <[EMAIL PROTECTED]>
Cc: Rohit Seth <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
---
arch/i386/kernel/nmi.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
Index: linux-2.6.20-rc4-mm1-bo/arch/i386/kernel/nmi.c
===================================================================
--- linux-2.6.20-rc4-mm1-bo.orig/arch/i386/kernel/nmi.c
+++ linux-2.6.20-rc4-mm1-bo/arch/i386/kernel/nmi.c
@@ -23,6 +23,7 @@
#include <linux/dmi.h>
#include <linux/kprobes.h>
#include <linux/cpumask.h>
+#include <linux/kernel_stat.h>
#include <asm/smp.h>
#include <asm/nmi.h>
@@ -971,9 +972,13 @@ __kprobes int nmi_watchdog_tick(struct p
cpu_clear(cpu, backtrace_mask);
}
- sum = per_cpu(irq_stat, cpu).apic_timer_irqs;
+ /*
+ * Take the local apic timer and PIT/HPET into account. We don't
+ * know which one is active, when we have highres/dyntick on
+ */
+ sum = per_cpu(irq_stat, cpu).apic_timer_irqs + kstat_irqs(0);
- /* if the apic timer isn't firing, this cpu isn't doing much */
+ /* if the none of the timers isn't firing, this cpu isn't doing much */
if (!touched && last_irq_sums[cpu] == sum) {
/*
* Ayiee, looks like this CPU is stuck ...
--
-
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