x86: use per_cpu data in nmi_32

[safe/jmp/linux-2.6] / arch / x86 / kernel / nmi_32.c

diff --git a/arch/x86/kernel/nmi_32.c b/arch/x86/kernel/nmi_32.c
index 11b14bb..69bdae5 100644 (file)
--- a/arch/x86/kernel/nmi_32.c
+++ b/arch/x86/kernel/nmi_32.c
@@ -293,9 +293,9 @@ void stop_apic_nmi_watchdog(void *unused)
  *  here too!]
  */
 
-static unsigned int
-       last_irq_sums [NR_CPUS],
-       alert_counter [NR_CPUS];
+static DEFINE_PER_CPU(unsigned, last_irq_sum);
+static DEFINE_PER_CPU(local_t, alert_counter);
+static DEFINE_PER_CPU(int, nmi_touch);
 
 void touch_nmi_watchdog(void)
 {
@@ -303,12 +303,13 @@ void touch_nmi_watchdog(void)
                unsigned cpu;
 
                /*
-                * Just reset the alert counters, (other CPUs might be
-                * spinning on locks we hold):
+                * Tell other CPUs to reset their alert counters. We cannot
+                * do it ourselves because the alert count increase is not
+                * atomic.
                 */
                for_each_present_cpu(cpu) {
-                       if (alert_counter[cpu])
-                               alert_counter[cpu] = 0;
+                       if (per_cpu(nmi_touch, cpu) != 1)
+                               per_cpu(nmi_touch, cpu) = 1;
                }
        }
 
@@ -358,22 +359,26 @@ nmi_watchdog_tick(struct pt_regs *regs, unsigned reason)
         */
        sum = per_cpu(irq_stat, cpu).apic_timer_irqs +
                per_cpu(irq_stat, cpu).irq0_irqs;
+       if (__get_cpu_var(nmi_touch)) {
+               __get_cpu_var(nmi_touch) = 0;
+               touched = 1;
+       }
 
        /* if the none of the timers isn't firing, this cpu isn't doing much */
-       if (!touched && last_irq_sums[cpu] == sum) {
+       if (!touched && __get_cpu_var(last_irq_sum) == sum) {
                /*
                 * Ayiee, looks like this CPU is stuck ...
                 * wait a few IRQs (5 seconds) before doing the oops ...
                 */
-               alert_counter[cpu]++;
-               if (alert_counter[cpu] == 5*nmi_hz)
+               local_inc(&__get_cpu_var(alert_counter));
+               if (local_read(&__get_cpu_var(alert_counter)) == 5*nmi_hz)
                        /*
                         * die_nmi will return ONLY if NOTIFY_STOP happens..
                         */
                        die_nmi(regs, "BUG: NMI Watchdog detected LOCKUP");
        } else {
-               last_irq_sums[cpu] = sum;
-               alert_counter[cpu] = 0;
+               __get_cpu_var(last_irq_sum) = sum;
+               local_set(&__get_cpu_var(alert_counter), 0);
        }
        /* see if the nmi watchdog went off */
        if (!__get_cpu_var(wd_enabled))