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Commit 68d3f1d8 authored by Don Zickus's avatar Don Zickus Committed by Ingo Molnar
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lockup_detector: Sync touch_*_watchdog back to old semantics 



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: default avatarDon Zickus <dzickus@redhat.com>
Acked-by: default avatarCyrill 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: default avatarIngo Molnar <mingo@elte.hu>
parent 3aaba20f

kernel/watchdog.c

+12 −5
Original line number Diff line number Diff line
@@ -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)