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lockup_detector: Sync touch_*_watchdog back to old semantics

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During my rewrite, the semantics of touch_nmi_watchdog and
touch_softlockup_watchdog changed enough to break some drivers
(mostly over preemptable regions).

These are cases where long delays on one CPU (due to
print_delay for example) can cause long delays on other
CPUs - so we must 'touch' the nmi_watchdog flag of those
other CPUs as well.

This change brings those touch_*_watchdog() functions back in line
with to how they used to work.

Signed-off-by: Don Zickus <dzickus@redhat.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: peterz@infradead.org
Cc: fweisbec@gmail.com
LKML-Reference: <1283310009-22168-2-git-send-email-dzickus@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Don Zickus 2010-08-31 23:00:07 -04:00 committed by Ingo Molnar
parent 3aaba20f26
commit 68d3f1d810
1 changed files with 12 additions and 5 deletions
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17
kernel/watchdog.c
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@ -122,7 +122,7 @@ static void __touch_watchdog(void)
void touch_softlockup_watchdog(void)
{
__get_cpu_var(watchdog_touch_ts) = 0;
__raw_get_cpu_var(watchdog_touch_ts) = 0;
}
EXPORT_SYMBOL(touch_softlockup_watchdog);
@ -142,7 +142,14 @@ void touch_all_softlockup_watchdogs(void)
#ifdef CONFIG_HARDLOCKUP_DETECTOR
void touch_nmi_watchdog(void)
{
__get_cpu_var(watchdog_nmi_touch) = true;
if (watchdog_enabled) {
unsigned cpu;
for_each_present_cpu(cpu) {
if (per_cpu(watchdog_nmi_touch, cpu) != true)
per_cpu(watchdog_nmi_touch, cpu) = true;
}
}
touch_softlockup_watchdog();
}
EXPORT_SYMBOL(touch_nmi_watchdog);
@ -433,6 +440,9 @@ static int watchdog_enable(int cpu)
wake_up_process(p);
}
/* if any cpu succeeds, watchdog is considered enabled for the system */
watchdog_enabled = 1;
return 0;
}
@ -455,9 +465,6 @@ static void watchdog_disable(int cpu)
per_cpu(softlockup_watchdog, cpu) = NULL;
kthread_stop(p);
}
/* if any cpu succeeds, watchdog is considered enabled for the system */
watchdog_enabled = 1;
}
static void watchdog_enable_all_cpus(void)