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-rw-r--r--arch/powerpc/kernel/watchdog.c17
-rw-r--r--include/linux/nmi.h2
-rw-r--r--kernel/watchdog.c31
3 files changed, 33 insertions, 17 deletions
diff --git a/arch/powerpc/kernel/watchdog.c b/arch/powerpc/kernel/watchdog.c
index 5ded171f02d6..291af79a9826 100644
--- a/arch/powerpc/kernel/watchdog.c
+++ b/arch/powerpc/kernel/watchdog.c
@@ -355,17 +355,18 @@ static void watchdog_calc_timeouts(void)
wd_timer_period_ms = watchdog_thresh * 1000 * 2 / 5;
}
-void watchdog_nmi_reconfigure(void)
+void watchdog_nmi_reconfigure(bool run)
{
int cpu;
- watchdog_calc_timeouts();
-
- for_each_cpu(cpu, &wd_cpus_enabled)
- stop_wd_on_cpu(cpu);
-
- for_each_cpu_and(cpu, cpu_online_mask, &watchdog_cpumask)
- start_wd_on_cpu(cpu);
+ if (!run) {
+ for_each_cpu(cpu, &wd_cpus_enabled)
+ stop_wd_on_cpu(cpu);
+ } else {
+ watchdog_calc_timeouts();
+ for_each_cpu_and(cpu, cpu_online_mask, &watchdog_cpumask)
+ start_wd_on_cpu(cpu);
+ }
}
/*
diff --git a/include/linux/nmi.h b/include/linux/nmi.h
index 4a8d1037364e..eee255bc0fd6 100644
--- a/include/linux/nmi.h
+++ b/include/linux/nmi.h
@@ -103,6 +103,8 @@ static inline void arch_touch_nmi_watchdog(void) {}
#endif
#endif
+void watchdog_nmi_reconfigure(bool run);
+
/**
* touch_nmi_watchdog - restart NMI watchdog timeout.
*
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index baae9fc95031..5693afd2b8ea 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -112,17 +112,25 @@ void __weak watchdog_nmi_disable(unsigned int cpu)
hardlockup_detector_perf_disable();
}
-/*
- * watchdog_nmi_reconfigure can be implemented to be notified after any
- * watchdog configuration change. The arch hardlockup watchdog should
- * respond to the following variables:
+/**
+ * watchdog_nmi_reconfigure - Optional function to reconfigure NMI watchdogs
+ * @run: If false stop the watchdogs on all enabled CPUs
+ * If true start the watchdogs on all enabled CPUs
+ *
+ * The core call order is:
+ * watchdog_nmi_reconfigure(false);
+ * update_variables();
+ * watchdog_nmi_reconfigure(true);
+ *
+ * The second call which starts the watchdogs again guarantees that the
+ * following variables are stable across the call.
* - watchdog_enabled
* - watchdog_thresh
* - watchdog_cpumask
- * - sysctl_hardlockup_all_cpu_backtrace
- * - hardlockup_panic
+ *
+ * After the call the variables can be changed again.
*/
-void __weak watchdog_nmi_reconfigure(void) { }
+void __weak watchdog_nmi_reconfigure(bool run) { }
#ifdef CONFIG_SOFTLOCKUP_DETECTOR
@@ -515,10 +523,12 @@ static void softlockup_unpark_threads(void)
static void softlockup_reconfigure_threads(bool enabled)
{
+ watchdog_nmi_reconfigure(false);
softlockup_park_all_threads();
set_sample_period();
if (enabled)
softlockup_unpark_threads();
+ watchdog_nmi_reconfigure(true);
}
/*
@@ -559,7 +569,11 @@ static inline void watchdog_unpark_threads(void) { }
static inline int watchdog_enable_all_cpus(void) { return 0; }
static inline void watchdog_disable_all_cpus(void) { }
static inline void softlockup_init_threads(void) { }
-static inline void softlockup_reconfigure_threads(bool enabled) { }
+static void softlockup_reconfigure_threads(bool enabled)
+{
+ watchdog_nmi_reconfigure(false);
+ watchdog_nmi_reconfigure(true);
+}
#endif /* !CONFIG_SOFTLOCKUP_DETECTOR */
static void __lockup_detector_cleanup(void)
@@ -599,7 +613,6 @@ static void proc_watchdog_update(void)
/* Remove impossible cpus to keep sysctl output clean. */
cpumask_and(&watchdog_cpumask, &watchdog_cpumask, cpu_possible_mask);
softlockup_reconfigure_threads(watchdog_enabled && watchdog_thresh);
- watchdog_nmi_reconfigure();
}
/*