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authorThomas Gleixner <tglx@linutronix.de>2007-10-12 23:04:06 +0200
committerThomas Gleixner <tglx@inhelltoy.tec.linutronix.de>2007-10-12 23:04:06 +0200
commit3c9aea47425885ec8b1f7b0df88c2ebc6f747c9d (patch)
tree17fefa5b3d6cef5f92ac07551ae27c3228c970ff
parentc8a1d398de70a7774359b4720c392891cdd485f9 (diff)
x86: Fix irq0 / local apic timer accounting
The clock events merge introduced a change to the nmi watchdog code to handle the not longer increasing local apic timer count in the broadcast mode. This is fine for UP, but on SMP it pampers over a stuck CPU which is not handling the broadcast interrupt due to the unconditional sum up of local apic timer count and irq0 count. To cover all cases we need to keep track on which CPU irq0 is handled. In theory this is CPU#0 due to the explicit disabling of irq balancing for irq0, but there are systems which ignore this on the hardware level. The per cpu irq0 accounting allows us to remove the irq0 to CPU0 binding as well. Add a per cpu counter for irq0 and evaluate this instead of the global irq0 count in the nmi watchdog code. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
-rw-r--r--arch/x86/kernel/nmi_32.c3
-rw-r--r--arch/x86/kernel/time_32.c3
-rw-r--r--include/asm-x86/hardirq_32.h1
3 files changed, 6 insertions, 1 deletions
diff --git a/arch/x86/kernel/nmi_32.c b/arch/x86/kernel/nmi_32.c
index c7227e2180f..95d3fc203cf 100644
--- a/arch/x86/kernel/nmi_32.c
+++ b/arch/x86/kernel/nmi_32.c
@@ -353,7 +353,8 @@ __kprobes int nmi_watchdog_tick(struct pt_regs * regs, unsigned reason)
* 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_cpu(cpu).irqs[0];
+ sum = per_cpu(irq_stat, cpu).apic_timer_irqs +
+ per_cpu(irq_stat, cpu).irq0_irqs;
/* if the none of the timers isn't firing, this cpu isn't doing much */
if (!touched && last_irq_sums[cpu] == sum) {
diff --git a/arch/x86/kernel/time_32.c b/arch/x86/kernel/time_32.c
index 19a6c678d02..56dadfc2f41 100644
--- a/arch/x86/kernel/time_32.c
+++ b/arch/x86/kernel/time_32.c
@@ -157,6 +157,9 @@ EXPORT_SYMBOL(profile_pc);
*/
irqreturn_t timer_interrupt(int irq, void *dev_id)
{
+ /* Keep nmi watchdog up to date */
+ per_cpu(irq_stat, smp_processor_id()).irq0_irqs++;
+
#ifdef CONFIG_X86_IO_APIC
if (timer_ack) {
/*
diff --git a/include/asm-x86/hardirq_32.h b/include/asm-x86/hardirq_32.h
index 0e358dc405f..34649585bb5 100644
--- a/include/asm-x86/hardirq_32.h
+++ b/include/asm-x86/hardirq_32.h
@@ -9,6 +9,7 @@ typedef struct {
unsigned long idle_timestamp;
unsigned int __nmi_count; /* arch dependent */
unsigned int apic_timer_irqs; /* arch dependent */
+ unsigned int irq0_irqs;
} ____cacheline_aligned irq_cpustat_t;
DECLARE_PER_CPU(irq_cpustat_t, irq_stat);