From f2890255b0ade497893d1e5e99f519b5c1d50f7d Mon Sep 17 00:00:00 2001
From: Andrew Morton <akpm@linux-foundation.org>
Date: Tue, 17 Jul 2007 04:03:57 -0700
Subject: [PATCH] i386: speedup touch_nmi_watchdog
Avoid dirtying remote cpu's memory if it already has the correct value.
Cc: Andi Kleen <ak@suse.de>
Cc: Konrad Rzeszutek <konrad@darnok.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
arch/i386/kernel/nmi.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/arch/i386/kernel/nmi.c b/arch/i386/kernel/nmi.c
index fba121f7973f7..03b7f5584d713 100644
--- a/arch/i386/kernel/nmi.c
+++ b/arch/i386/kernel/nmi.c
@@ -295,7 +295,7 @@ static unsigned int
last_irq_sums [NR_CPUS],
alert_counter [NR_CPUS];
-void touch_nmi_watchdog (void)
+void touch_nmi_watchdog(void)
{
if (nmi_watchdog > 0) {
unsigned cpu;
@@ -304,8 +304,10 @@ void touch_nmi_watchdog (void)
* Just reset the alert counters, (other CPUs might be
* spinning on locks we hold):
*/
- for_each_present_cpu (cpu)
- alert_counter[cpu] = 0;
+ for_each_present_cpu(cpu) {
+ if (alert_counter[cpu])
+ alert_counter[cpu] = 0;
+ }
}
/*
--
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