The patch titled
Subject: watchdog: rename watchdog_suspend() and watchdog_resume()
has been added to the -mm tree. Its filename is
watchdog-rename-watchdog_suspend-and-watchdog_resume.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/watchdog-rename-watchdog_suspend-and-watchdog_resume.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/watchdog-rename-watchdog_suspend-and-watchdog_resume.patch
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------------------------------------------------------
From: Ulrich Obergfell <uobergfe@xxxxxxxxxx>
Subject: watchdog: rename watchdog_suspend() and watchdog_resume()
Rename watchdog_suspend() to lockup_detector_suspend() and
watchdog_resume() to lockup_detector_resume() to avoid confusion with the
watchdog subsystem and to be consistent with the existing name
lockup_detector_init().
Also provide comment blocks to explain the watchdog_running and
watchdog_suspended variables and their relationship.
Signed-off-by: Ulrich Obergfell <uobergfe@xxxxxxxxxx>
Reviewed-by: Aaron Tomlin <atomlin@xxxxxxxxxx>
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
Cc: Don Zickus <dzickus@xxxxxxxxxx>
Cc: Ulrich Obergfell <uobergfe@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Chris Metcalf <cmetcalf@xxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/cpu/perf_event_intel.c | 4 +--
include/linux/nmi.h | 8 +++----
kernel/watchdog.c | 26 +++++++++++++++++++----
3 files changed, 28 insertions(+), 10 deletions(-)
diff -puN arch/x86/kernel/cpu/perf_event_intel.c~watchdog-rename-watchdog_suspend-and-watchdog_resume arch/x86/kernel/cpu/perf_event_intel.c
--- a/arch/x86/kernel/cpu/perf_event_intel.c~watchdog-rename-watchdog_suspend-and-watchdog_resume
+++ a/arch/x86/kernel/cpu/perf_event_intel.c
@@ -3368,7 +3368,7 @@ static __init int fixup_ht_bug(void)
return 0;
}
- if (watchdog_suspend() != 0) {
+ if (lockup_detector_suspend() != 0) {
pr_debug("failed to disable PMU erratum BJ122, BV98, HSD29 workaround\n");
return 0;
}
@@ -3379,7 +3379,7 @@ static __init int fixup_ht_bug(void)
x86_pmu.commit_scheduling = NULL;
x86_pmu.stop_scheduling = NULL;
- watchdog_resume();
+ lockup_detector_resume();
get_online_cpus();
diff -puN include/linux/nmi.h~watchdog-rename-watchdog_suspend-and-watchdog_resume include/linux/nmi.h
--- a/include/linux/nmi.h~watchdog-rename-watchdog_suspend-and-watchdog_resume
+++ a/include/linux/nmi.h
@@ -78,15 +78,15 @@ extern int proc_watchdog_thresh(struct c
void __user *, size_t *, loff_t *);
extern int proc_watchdog_cpumask(struct ctl_table *, int,
void __user *, size_t *, loff_t *);
-extern int watchdog_suspend(void);
-extern void watchdog_resume(void);
+extern int lockup_detector_suspend(void);
+extern void lockup_detector_resume(void);
#else
-static inline int watchdog_suspend(void)
+static inline int lockup_detector_suspend(void)
{
return 0;
}
-static inline void watchdog_resume(void)
+static inline void lockup_detector_resume(void)
{
}
#endif
diff -puN kernel/watchdog.c~watchdog-rename-watchdog_suspend-and-watchdog_resume kernel/watchdog.c
--- a/kernel/watchdog.c~watchdog-rename-watchdog_suspend-and-watchdog_resume
+++ a/kernel/watchdog.c
@@ -67,8 +67,26 @@ unsigned long *watchdog_cpumask_bits = c
#define for_each_watchdog_cpu(cpu) \
for_each_cpu_and((cpu), cpu_online_mask, &watchdog_cpumask)
-static int __read_mostly watchdog_suspended;
+/*
+ * The 'watchdog_running' variable is set to 1 when the watchdog threads
+ * are registered/started and is set to 0 when the watchdog threads are
+ * unregistered/stopped, so it is an indicator whether the threads exist.
+ */
static int __read_mostly watchdog_running;
+/*
+ * If a subsystem has a need to deactivate the watchdog temporarily, it
+ * can use the suspend/resume interface to achieve this. The content of
+ * the 'watchdog_suspended' variable reflects this state. Existing threads
+ * are parked/unparked by the lockup_detector_{suspend|resume} functions
+ * (see comment blocks pertaining to those functions for further details).
+ *
+ * 'watchdog_suspended' also prevents threads from being registered/started
+ * or unregistered/stopped via parameters in /proc/sys/kernel, so the state
+ * of 'watchdog_running' cannot change while the watchdog is deactivated
+ * temporarily (see related code in 'proc' handlers).
+ */
+static int __read_mostly watchdog_suspended;
+
static u64 __read_mostly sample_period;
static DEFINE_PER_CPU(unsigned long, watchdog_touch_ts);
@@ -669,7 +687,7 @@ static void watchdog_unpark_threads(void
/*
* Suspend the hard and soft lockup detector by parking the watchdog threads.
*/
-int watchdog_suspend(void)
+int lockup_detector_suspend(void)
{
int ret = 0;
@@ -679,7 +697,7 @@ int watchdog_suspend(void)
* the 'watchdog_suspended' variable). If the watchdog threads are
* running, the first caller takes care that they will be parked.
* The state of 'watchdog_running' cannot change while a suspend
- * request is active (see related changes in 'proc' handlers).
+ * request is active (see related code in 'proc' handlers).
*/
if (watchdog_running && !watchdog_suspended)
ret = watchdog_park_threads();
@@ -695,7 +713,7 @@ int watchdog_suspend(void)
/*
* Resume the hard and soft lockup detector by unparking the watchdog threads.
*/
-void watchdog_resume(void)
+void lockup_detector_resume(void)
{
mutex_lock(&watchdog_proc_mutex);
_
Patches currently in -mm which might be from uobergfe@xxxxxxxxxx are
smpboot-fix-memory-leak-on-error-handling.patch
smpboot-make-cleanup-to-mirror-setup.patch
smpboot-allow-to-pass-the-cpumask-on-per-cpu-thread-registration.patch
watchdog-simplify-housekeeping-affinity-with-the-appropriate-mask.patch
watchdog-introduce-watchdog_park_threads-and-watchdog_unpark_threads.patch
watchdog-introduce-watchdog_suspend-and-watchdog_resume.patch
watchdog-introduce-watchdog_suspend-and-watchdog_resume-fix.patch
watchdog-use-park-unpark-functions-in-update_watchdog_all_cpus.patch
watchdog-use-suspend-resume-interface-in-fixup_ht_bug.patch
watchdog-use-suspend-resume-interface-in-fixup_ht_bug-fix.patch
watchdog-use-suspend-resume-interface-in-fixup_ht_bug-fix-2.patch
watchdog-rename-watchdog_suspend-and-watchdog_resume.patch
linux-next.patch
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