x86: use per_cpu data in nmi_32

use per_cpu for per CPU data.

Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 17 insertions, 12 deletions

diff --git a/arch/x86/kernel/nmi_32.c b/arch/x86/kernel/nmi_32.c
index 11b14bbaa61e..69bdae555c18 100644
--- 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))