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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>
This commit is contained in:
Mandeep Singh Baines 2011-05-22 22:10:22 -07:00 committed by Ingo Molnar
parent e04ab2bc41
commit 586692a5a5
4 changed files with 20 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
include/linux/nmi.h
View File

@ -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

1
include/linux/sched.h
View File

@ -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)

12
kernel/sysctl.c
View File

@ -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)

25
kernel/watchdog.c
View File

@ -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 */