powerpc/watchdog: Moderate touch_nmi_watchdog overhead

[karo-tx-linux.git] / arch / powerpc / kernel / watchdog.c

diff --git a/arch/powerpc/kernel/watchdog.c b/arch/powerpc/kernel/watchdog.c
index b67f8b03a32d0f12ce29eeb4ac3be0a97384fe72..426dd34891d68b34991d92dcea64be61937d40a4 100644 (file)
--- a/arch/powerpc/kernel/watchdog.c
+++ b/arch/powerpc/kernel/watchdog.c
@@ -71,15 +71,20 @@ static inline void wd_smp_lock(unsigned long *flags)
         * This may be called from low level interrupt handlers at some
         * point in future.
         */
-       local_irq_save(*flags);
-       while (unlikely(test_and_set_bit_lock(0, &__wd_smp_lock)))
-               cpu_relax();
+       raw_local_irq_save(*flags);
+       hard_irq_disable(); /* Make it soft-NMI safe */
+       while (unlikely(test_and_set_bit_lock(0, &__wd_smp_lock))) {
+               raw_local_irq_restore(*flags);
+               spin_until_cond(!test_bit(0, &__wd_smp_lock));
+               raw_local_irq_save(*flags);
+               hard_irq_disable();
+       }
 }
 
 static inline void wd_smp_unlock(unsigned long *flags)
 {
        clear_bit_unlock(0, &__wd_smp_lock);
-       local_irq_restore(*flags);
+       raw_local_irq_restore(*flags);
 }
 
 static void wd_lockup_ipi(struct pt_regs *regs)
@@ -258,9 +263,11 @@ static void wd_timer_fn(unsigned long data)
 
 void arch_touch_nmi_watchdog(void)
 {
+       unsigned long ticks = tb_ticks_per_usec * wd_timer_period_ms * 1000;
        int cpu = smp_processor_id();
 
-       watchdog_timer_interrupt(cpu);
+       if (get_tb() - per_cpu(wd_timer_tb, cpu) >= ticks)
+               watchdog_timer_interrupt(cpu);
 }
 EXPORT_SYMBOL(arch_touch_nmi_watchdog);