[PATCH v2 2/9] watchdog: introduce the proc_watchdog_update() function

From: Ulrich Obergfell
Date: Fri Oct 17 2014 - 13:01:57 EST


This series introduces a separate handler for each watchdog parameter
in /proc/sys/kernel. The separate handlers need a common function that
they can call to update the run state of the lockup detectors, or to
have the lockup detectors use a new sample period.

Signed-off-by: Ulrich Obergfell <uobergfe@xxxxxxxxxx>
---
kernel/watchdog.c | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index f8da756..da16a50 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -679,6 +679,29 @@ static void watchdog_disable_all_cpus(void)
}

/*
+ * Update the run state of the lockup detectors.
+ */
+static int proc_watchdog_update(void)
+{
+ int err = 0;
+
+ /*
+ * Watchdog threads won't be started if they are already active.
+ * The 'watchdog_running' variable in watchdog_*_all_cpus() takes
+ * care of this. If those threads are already active, the sample
+ * period will be updated and the lockup detectors will be enabled
+ * or disabled 'on the fly'.
+ */
+ if (watchdog_enabled && watchdog_thresh)
+ err = watchdog_enable_all_cpus(true);
+ else
+ watchdog_disable_all_cpus();
+
+ return err;
+
+}
+
+/*
* proc handler for /proc/sys/kernel/nmi_watchdog,watchdog_thresh
*/

--
1.7.11.7

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