lkml.org 
[lkml]   [2011]   [May]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip:perf/urgent] watchdog: Disable watchdog when thresh is zero
Commit-ID:  586692a5a5fc5740c8a46abc0f2365495c2d7c5f
Gitweb: http://git.kernel.org/tip/586692a5a5fc5740c8a46abc0f2365495c2d7c5f
Author: Mandeep Singh Baines <msb@chromium.org>
AuthorDate: Sun, 22 May 2011 22:10:22 -0700
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Mon, 23 May 2011 11:58:59 +0200

watchdog: Disable watchdog when thresh is zero

This restores the previous behavior of softlock_thresh.

Currently, setting watchdog_thresh to zero causes the watchdog
kthreads to consume a lot of CPU.

In addition, the logic of proc_dowatchdog_thresh and
proc_dowatchdog_enabled has been factored into proc_dowatchdog.

Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Cc: Marcin Slusarz <marcin.slusarz@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/1306127423-3347-3-git-send-email-msb@chromium.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
LKML-Reference: <20110517071018.GE22305@elte.hu>
---
include/linux/nmi.h | 5 +++--
include/linux/sched.h | 1 -
kernel/sysctl.c | 12 ++++++++----
kernel/watchdog.c | 25 +++++++++----------------
4 files changed, 20 insertions(+), 23 deletions(-)

diff --git a/include/linux/nmi.h b/include/linux/nmi.h
index c536f85..5317b8b 100644
--- a/include/linux/nmi.h
+++ b/include/linux/nmi.h
@@ -47,9 +47,10 @@ static inline bool trigger_all_cpu_backtrace(void)
int hw_nmi_is_cpu_stuck(struct pt_regs *);
u64 hw_nmi_get_sample_period(void);
extern int watchdog_enabled;
+extern int watchdog_thresh;
struct ctl_table;
-extern int proc_dowatchdog_enabled(struct ctl_table *, int ,
- void __user *, size_t *, loff_t *);
+extern int proc_dowatchdog(struct ctl_table *, int ,
+ void __user *, size_t *, loff_t *);
#endif

#endif
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 12211e1..d8b2d0b 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -315,7 +315,6 @@ extern int proc_dowatchdog_thresh(struct ctl_table *table, int write,
void __user *buffer,
size_t *lenp, loff_t *ppos);
extern unsigned int softlockup_panic;
-extern int softlockup_thresh;
void lockup_detector_init(void);
#else
static inline void touch_softlockup_watchdog(void)
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index c0bb324..3dd0c46 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -730,14 +730,16 @@ static struct ctl_table kern_table[] = {
.data = &watchdog_enabled,
.maxlen = sizeof (int),
.mode = 0644,
- .proc_handler = proc_dowatchdog_enabled,
+ .proc_handler = proc_dowatchdog,
+ .extra1 = &zero,
+ .extra2 = &one,
},
{
.procname = "watchdog_thresh",
- .data = &softlockup_thresh,
+ .data = &watchdog_thresh,
.maxlen = sizeof(int),
.mode = 0644,
- .proc_handler = proc_dowatchdog_thresh,
+ .proc_handler = proc_dowatchdog,
.extra1 = &neg_one,
.extra2 = &sixty,
},
@@ -755,7 +757,9 @@ static struct ctl_table kern_table[] = {
.data = &watchdog_enabled,
.maxlen = sizeof (int),
.mode = 0644,
- .proc_handler = proc_dowatchdog_enabled,
+ .proc_handler = proc_dowatchdog,
+ .extra1 = &zero,
+ .extra2 = &one,
},
#endif
#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index cf0e09f..6030191 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -28,7 +28,7 @@
#include <linux/perf_event.h>

int watchdog_enabled = 1;
-int __read_mostly softlockup_thresh = 60;
+int __read_mostly watchdog_thresh = 60;

static DEFINE_PER_CPU(unsigned long, watchdog_touch_ts);
static DEFINE_PER_CPU(struct task_struct *, softlockup_watchdog);
@@ -105,12 +105,12 @@ static unsigned long get_timestamp(int this_cpu)
static unsigned long get_sample_period(void)
{
/*
- * convert softlockup_thresh from seconds to ns
+ * convert watchdog_thresh from seconds to ns
* the divide by 5 is to give hrtimer 5 chances to
* increment before the hardlockup detector generates
* a warning
*/
- return softlockup_thresh * (NSEC_PER_SEC / 5);
+ return watchdog_thresh * (NSEC_PER_SEC / 5);
}

/* Commands for resetting the watchdog */
@@ -182,7 +182,7 @@ static int is_softlockup(unsigned long touch_ts)
unsigned long now = get_timestamp(smp_processor_id());

/* Warn about unreasonable delays: */
- if (time_after(now, touch_ts + softlockup_thresh))
+ if (time_after(now, touch_ts + watchdog_thresh))
return now - touch_ts;

return 0;
@@ -501,19 +501,19 @@ static void watchdog_disable_all_cpus(void)
/* sysctl functions */
#ifdef CONFIG_SYSCTL
/*
- * proc handler for /proc/sys/kernel/nmi_watchdog
+ * proc handler for /proc/sys/kernel/nmi_watchdog,watchdog_thresh
*/

-int proc_dowatchdog_enabled(struct ctl_table *table, int write,
- void __user *buffer, size_t *length, loff_t *ppos)
+int proc_dowatchdog(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos)
{
int ret;

- ret = proc_dointvec(table, write, buffer, length, ppos);
+ ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
if (ret || !write)
goto out;

- if (watchdog_enabled)
+ if (watchdog_enabled && watchdog_thresh)
watchdog_enable_all_cpus();
else
watchdog_disable_all_cpus();
@@ -521,13 +521,6 @@ int proc_dowatchdog_enabled(struct ctl_table *table, int write,
out:
return ret;
}
-
-int proc_dowatchdog_thresh(struct ctl_table *table, int write,
- void __user *buffer,
- size_t *lenp, loff_t *ppos)
-{
- return proc_dointvec_minmax(table, write, buffer, lenp, ppos);
-}
#endif /* CONFIG_SYSCTL */



\
 
 \ /
  Last update: 2011-05-23 13:15    [W:0.056 / U:19.736 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site