Messages in this thread Patch in this message | | | Date | Tue, 1 Nov 2005 12:33:04 +0100 | From | Ingo Molnar <> | Subject | Re: 2.6.14-rc5-rt6 -- False NMI lockup detects |
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* Steven Rostedt <rostedt@goodmis.org> wrote:
> Hi Ingo and Thomas, > > On some of my machines, I've been experiencing false NMI lockups. > This usually happens on slower machines, and taking a look into this, > it seems to be due to a short time where no processes are using > timers, and the ktimer interrupts aren't needed. So the APIC timer, > which now is used only for the ktimers, has a five second pause, and > causes the NMI to go off. The NMI uses the apic timer to determine > lockups. > > So, I added a more generic method. This only works for x86 for now, > but it has a #ifdef to keep other archs working until it implements > this as well. I added a nmi_irq_incr which is called by __do_IRQ in > the generic code. This is what is used in the NMI code to determine > if the CPU has locked up. This way we don't have to worry about what > resource we are using for timers.
but e.g. the APIC timer doesnt go through do_IRQ(), it has its own special IRQ entry code. The simple solution would be to also include the IRQ#0 count in the NMI watchdog detection condition - i.e. something like the patch below. Hm?
Ingo
Index: linux/arch/i386/kernel/nmi.c =================================================================== --- linux.orig/arch/i386/kernel/nmi.c +++ linux/arch/i386/kernel/nmi.c @@ -521,7 +521,7 @@ void notrace nmi_watchdog_tick (struct p */ int sum, cpu = smp_processor_id(); - sum = per_cpu(irq_stat, cpu).apic_timer_irqs; + sum = per_cpu(irq_stat, cpu).apic_timer_irqs + kstat_irqs(0); profile_tick(CPU_PROFILING, regs); if (nmi_show_regs[cpu]) { - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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