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authorMandeep Singh Baines <msb@chromium.org>2011-05-22 22:10:22 -0700
committerIngo Molnar <mingo@elte.hu>2011-05-23 11:58:59 +0200
commit586692a5a5fc5740c8a46abc0f2365495c2d7c5f (patch)
treebc08228e67a968d83691c9efc5ea1feda9e6f98b
parente04ab2bc41b35c0cb6cdb07c8443f91aa738cf78 (diff)
downloadlinux-586692a5a5fc5740c8a46abc0f2365495c2d7c5f.tar.bz2
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>
-rw-r--r--include/linux/nmi.h5
-rw-r--r--include/linux/sched.h1
-rw-r--r--kernel/sysctl.c12
-rw-r--r--kernel/watchdog.c25
4 files changed, 20 insertions, 23 deletions
diff --git a/include/linux/nmi.h b/include/linux/nmi.h
index c536f8545f74..5317b8b2198f 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 12211e1666e2..d8b2d0bec0d8 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 c0bb32414b17..3dd0c46fa3bb 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 cf0e09f452e7..60301916f62e 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 */