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authorNicholas Piggin <npiggin@gmail.com>2017-07-12 14:35:49 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-07-12 16:26:02 -0700
commita10a842ff81a7e3810817b3b04e4c432b6191e21 (patch)
tree69439a65e117c22231067c1c56ae2777b3f857d9
parent05a4a95279311c3a4633b4277a5d21cfd616c6c7 (diff)
downloadlinux-a10a842ff81a7e3810817b3b04e4c432b6191e21.tar.bz2
kernel/watchdog: provide watchdog_nmi_reconfigure() for arch watchdogs
After reconfiguring watchdog sysctls etc., architecture specific watchdogs may not get all their parameters updated. watchdog_nmi_reconfigure() can be implemented to pull the new values in and set the arch NMI watchdog. [npiggin@gmail.com: add code comments] Link: http://lkml.kernel.org/r/20170617125933.774d3858@roar.ozlabs.ibm.com [arnd@arndb.de: hide unused function] Link: http://lkml.kernel.org/r/20170620204854.966601-1-arnd@arndb.de Link: http://lkml.kernel.org/r/20170616065715.18390-5-npiggin@gmail.com Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Don Zickus <dzickus@redhat.com> Tested-by: Babu Moger <babu.moger@oracle.com> [sparc] Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--kernel/watchdog.c48
1 files changed, 44 insertions, 4 deletions
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 1fba9c3d66dc..cabe3e9fb620 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -114,6 +114,10 @@ int __read_mostly watchdog_suspended;
/*
* These functions can be overridden if an architecture implements its
* own hardlockup detector.
+ *
+ * watchdog_nmi_enable/disable can be implemented to start and stop when
+ * softlockup watchdog threads start and stop. The arch must select the
+ * SOFTLOCKUP_DETECTOR Kconfig.
*/
int __weak watchdog_nmi_enable(unsigned int cpu)
{
@@ -123,6 +127,22 @@ void __weak watchdog_nmi_disable(unsigned int cpu)
{
}
+/*
+ * watchdog_nmi_reconfigure can be implemented to be notified after any
+ * watchdog configuration change. The arch hardlockup watchdog should
+ * respond to the following variables:
+ * - nmi_watchdog_enabled
+ * - watchdog_thresh
+ * - watchdog_cpumask
+ * - sysctl_hardlockup_all_cpu_backtrace
+ * - hardlockup_panic
+ * - watchdog_suspended
+ */
+void __weak watchdog_nmi_reconfigure(void)
+{
+}
+
+
#ifdef CONFIG_SOFTLOCKUP_DETECTOR
/* Helper for online, unparked cpus. */
@@ -600,6 +620,14 @@ static void watchdog_disable_all_cpus(void)
}
}
+#ifdef CONFIG_SYSCTL
+static int watchdog_update_cpus(void)
+{
+ return smpboot_update_cpumask_percpu_thread(
+ &watchdog_threads, &watchdog_cpumask);
+}
+#endif
+
#else /* SOFTLOCKUP */
static int watchdog_park_threads(void)
{
@@ -619,6 +647,13 @@ static void watchdog_disable_all_cpus(void)
{
}
+#ifdef CONFIG_SYSCTL
+static int watchdog_update_cpus(void)
+{
+ return 0;
+}
+#endif
+
static void set_sample_period(void)
{
}
@@ -651,6 +686,8 @@ int lockup_detector_suspend(void)
watchdog_enabled = 0;
}
+ watchdog_nmi_reconfigure();
+
mutex_unlock(&watchdog_proc_mutex);
return ret;
@@ -671,6 +708,8 @@ 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 +735,8 @@ static int proc_watchdog_update(void)
else
watchdog_disable_all_cpus();
+ watchdog_nmi_reconfigure();
+
return err;
}
@@ -881,12 +922,11 @@ 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);