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-rw-r--r--kernel/watchdog.c24
1 files changed, 12 insertions, 12 deletions
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index d117262..14bc092 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -3,12 +3,9 @@
*
* started by Don Zickus, Copyright (C) 2010 Red Hat, Inc.
*
- * this code detects hard lockups: incidents in where on a CPU
- * the kernel does not respond to anything except NMI.
- *
- * Note: Most of this code is borrowed heavily from softlockup.c,
- * so thanks to Ingo for the initial implementation.
- * Some chunks also taken from arch/x86/kernel/apic/nmi.c, thanks
+ * Note: Most of this code is borrowed heavily from the original softlockup
+ * detector, so thanks to Ingo for the initial implementation.
+ * Some chunks also taken from the old x86-specific nmi watchdog code, thanks
* to those contributors as well.
*/
@@ -117,9 +114,10 @@ static unsigned long get_sample_period(void)
{
/*
* convert watchdog_thresh from seconds to ns
- * the divide by 5 is to give hrtimer 5 chances to
- * increment before the hardlockup detector generates
- * a warning
+ * the divide by 5 is to give hrtimer several chances (two
+ * or three with the current relation between the soft
+ * and hard thresholds) to increment before the
+ * hardlockup detector generates a warning
*/
return get_softlockup_thresh() * (NSEC_PER_SEC / 5);
}
@@ -336,9 +334,11 @@ static int watchdog(void *unused)
set_current_state(TASK_INTERRUPTIBLE);
/*
- * Run briefly once per second to reset the softlockup timestamp.
- * If this gets delayed for more than 60 seconds then the
- * debug-printout triggers in watchdog_timer_fn().
+ * Run briefly (kicked by the hrtimer callback function) once every
+ * get_sample_period() seconds (4 seconds by default) to reset the
+ * softlockup timestamp. If this gets delayed for more than
+ * 2*watchdog_thresh seconds then the debug-printout triggers in
+ * watchdog_timer_fn().
*/
while (!kthread_should_stop()) {
__touch_watchdog();
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