softlockup: use cpu_clock() instead of sched_clock()

sched_clock() is not a reliable time-source, use cpu_clock() instead.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 4 deletions

diff --git a/kernel/softlockup.c b/kernel/softlockup.c
index 708d4882c0c3..68f7606b4160 100644
--- a/kernel/softlockup.c
+++ b/kernel/softlockup.c
@@ -40,14 +40,16 @@ static struct notifier_block panic_block = {
  * resolution, and we don't need to waste time with a big divide when
  * 2^30ns == 1.074s.
  */
-static unsigned long get_timestamp(void)
+static unsigned long get_timestamp(int this_cpu)
 {
-        return sched_clock() >> 30;  /* 2^30 ~= 10^9 */
+        return cpu_clock(this_cpu) >> 30;  /* 2^30 ~= 10^9 */
 }
 
 void touch_softlockup_watchdog(void)
 {
-        __raw_get_cpu_var(touch_timestamp) = get_timestamp();
+        int this_cpu = raw_smp_processor_id();
+
+        __raw_get_cpu_var(touch_timestamp) = get_timestamp(this_cpu);
 }
 EXPORT_SYMBOL(touch_softlockup_watchdog);
 
@@ -91,7 +93,7 @@ void softlockup_tick(void)
                 return;
         }
 
-        now = get_timestamp();
+        now = get_timestamp(this_cpu);
 
         /* Wake up the high-prio watchdog task every second: */
         if (now > (touch_timestamp + 1))