diff mbox

[v4,4/5] watchdog: provide watchdog_reconfigure() for arch watchdogs

Message ID 20170616065715.18390-5-npiggin@gmail.com (mailing list archive)
State Not Applicable
Headers show

Commit Message

Nicholas Piggin June 16, 2017, 6:57 a.m. UTC 
After reconfiguring watchdog sysctls etc., architecture specific
watchdogs may not get all their parameters updated.

watchdog_reconfigure() can be implemented to pull the new values
in and set the arch NMI watchdog.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 kernel/watchdog.c | 29 +++++++++++++++++++++++++----
 1 file changed, 25 insertions(+), 4 deletions(-)

Comments

Andrew Morton June 16, 2017, 6:24 p.m. UTC | #1 
On Fri, 16 Jun 2017 16:57:14 +1000 Nicholas Piggin <npiggin@gmail.com> wrote:

> After reconfiguring watchdog sysctls etc., architecture specific
> watchdogs may not get all their parameters updated.
> 
> watchdog_reconfigure() can be implemented to pull the new values
> in and set the arch NMI watchdog.
> 

I'll update the title and changelog to say "watchdog_nmi_reconfigure".

> --- a/kernel/watchdog.c
> +++ b/kernel/watchdog.c
> @@ -123,6 +123,11 @@ void __weak watchdog_nmi_disable(unsigned int cpu)
>  {
>  }
>  
> +void __weak watchdog_nmi_reconfigure(void)
> +{
> +}

Can we please get some documentation in here describing what it's for? 
How arch maintainers might use this?  When and why it is called, what
it must do?  etc.
diff mbox

Patch

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 1fba9c3d66dc..06cd965f64d2 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -123,6 +123,11 @@  void __weak watchdog_nmi_disable(unsigned int cpu)
 {
 }
 
+void __weak watchdog_nmi_reconfigure(void)
+{
+}
+
+
 #ifdef CONFIG_SOFTLOCKUP_DETECTOR
 
 /* Helper for online, unparked cpus. */
@@ -600,6 +605,12 @@  static void watchdog_disable_all_cpus(void)
 	}
 }
 
+static int watchdog_update_cpus(void)
+{
+	return smpboot_update_cpumask_percpu_thread(
+		    &watchdog_threads, &watchdog_cpumask);
+}
+
 #else /* SOFTLOCKUP */
 static int watchdog_park_threads(void)
 {
@@ -619,6 +630,11 @@  static void watchdog_disable_all_cpus(void)
 {
 }
 
+static int watchdog_update_cpus(void)
+{
+	return 0;
+}
+
 static void set_sample_period(void)
 {
 }
@@ -651,6 +667,8 @@  int lockup_detector_suspend(void)
 		watchdog_enabled = 0;
 	}
 
+	watchdog_nmi_reconfigure();
+
 	mutex_unlock(&watchdog_proc_mutex);
 
 	return ret;
@@ -671,6 +689,8 @@  void lockup_detector_resume(void)
 	if (watchdog_running && !watchdog_suspended)
 		watchdog_unpark_threads();
 
+	watchdog_nmi_reconfigure();
+
 	mutex_unlock(&watchdog_proc_mutex);
 	put_online_cpus();
 }
@@ -696,6 +716,8 @@  static int proc_watchdog_update(void)
 	else
 		watchdog_disable_all_cpus();
 
+	watchdog_nmi_reconfigure();
+
 	return err;
 
 }
@@ -881,12 +903,11 @@  int proc_watchdog_cpumask(struct ctl_table *table, int write,
 			 * a temporary cpumask, so we are likely not in a
 			 * position to do much else to make things better.
 			 */
-#ifdef CONFIG_SOFTLOCKUP_DETECTOR
-			if (smpboot_update_cpumask_percpu_thread(
-				    &watchdog_threads, &watchdog_cpumask) != 0)
+			if (watchdog_update_cpus() != 0)
 				pr_err("cpumask update failed\n");
-#endif
 		}
+
+		watchdog_nmi_reconfigure();
 	}
 out:
 	mutex_unlock(&watchdog_proc_mutex);