Commit 567f3e42 authored by Andrew Morton's avatar Andrew Morton Committed by Linus Torvalds

x86_64: 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f2890255
No related merge requests found
......@@ -296,7 +296,7 @@ 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)
void touch_nmi_watchdog(void)
{
if (nmi_watchdog > 0) {
unsigned cpu;
......@@ -306,8 +306,10 @@ void touch_nmi_watchdog (void)
* do it ourselves because the alert count increase is not
* atomic.
*/
for_each_present_cpu (cpu)
per_cpu(nmi_touch, cpu) = 1;
for_each_present_cpu(cpu) {
if (per_cpu(nmi_touch, cpu) != 1)
per_cpu(nmi_touch, cpu) = 1;
}
}
touch_softlockup_watchdog();
......
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