From 586692a5a5fc5740c8a46abc0f2365495c2d7c5f Mon Sep 17 00:00:00 2001 From: Mandeep Singh Baines Date: Sun, 22 May 2011 22:10:22 -0700 Subject: 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 Cc: Marcin Slusarz Cc: Don Zickus Cc: Peter Zijlstra Cc: Frederic Weisbecker Link: http://lkml.kernel.org/r/1306127423-3347-3-git-send-email-msb@chromium.org Signed-off-by: Ingo Molnar 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 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 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 */ -- cgit v1.2.3