Commit f8b5035b authored Feb 16, 2007 by Thomas Gleixner Committed by Linus Torvalds Feb 16, 2007

[PATCH] i386 prepare nmi watchdog for dynticks



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 <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Andi Kleen <ak@suse.de>
Cc: Zachary Amsden <zach@vmware.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Rohit Seth <rohitseth@google.com>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 74167347

arch/i386/kernel/nmi.c

+7 −2

Original line number	Diff line number	Diff line
		@@ -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>
		@@ -973,9 +974,13 @@ __kprobes int nmi_watchdog_tick(struct pt_regs * regs, unsigned reason)
		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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