From 8b414521bc5375ae8ba18c083af95d44b8da0d04 Mon Sep 17 00:00:00 2001 From: Marcelo Tosatti Date: Fri, 11 Oct 2013 21:39:26 -0300 Subject: [PATCH] hung_task: add method to reset detector In certain occasions it is possible for a hung task detector positive to be false: continuation from a paused VM, for example. Add a method to reset detection, similar as is done with other kernel watchdogs. Acked-by: Don Zickus Acked-by: Paolo Bonzini Signed-off-by: Marcelo Tosatti Signed-off-by: Gleb Natapov --- arch/x86/kernel/pvclock.c | 1 + include/linux/sched.h | 8 ++++++++ kernel/hung_task.c | 11 +++++++++++ 3 files changed, 20 insertions(+) diff --git a/arch/x86/kernel/pvclock.c b/arch/x86/kernel/pvclock.c index 6279928c0a71..2f355d229a58 100644 --- a/arch/x86/kernel/pvclock.c +++ b/arch/x86/kernel/pvclock.c @@ -48,6 +48,7 @@ void pvclock_touch_watchdogs(void) touch_softlockup_watchdog_sync(); clocksource_touch_watchdog(); rcu_cpu_stall_reset(); + reset_hung_task_detector(); } static atomic64_t last_value = ATOMIC64_INIT(0); diff --git a/include/linux/sched.h b/include/linux/sched.h index 6682da36b293..7bb4b4a2a101 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -285,6 +285,14 @@ static inline void lockup_detector_init(void) } #endif +#ifdef CONFIG_DETECT_HUNG_TASK +void reset_hung_task_detector(void); +#else +static inline void reset_hung_task_detector(void) +{ +} +#endif + /* Attach to any functions which should be ignored in wchan output. */ #define __sched __attribute__((__section__(".sched.text"))) diff --git a/kernel/hung_task.c b/kernel/hung_task.c index 3e97fb126e6b..dfdf51534b3e 100644 --- a/kernel/hung_task.c +++ b/kernel/hung_task.c @@ -203,6 +203,14 @@ int proc_dohung_task_timeout_secs(struct ctl_table *table, int write, return ret; } +static atomic_t reset_hung_task = ATOMIC_INIT(0); + +void reset_hung_task_detector(void) +{ + atomic_set(&reset_hung_task, 1); +} +EXPORT_SYMBOL_GPL(reset_hung_task_detector); + /* * kthread which checks for tasks stuck in D state */ @@ -216,6 +224,9 @@ static int watchdog(void *dummy) while (schedule_timeout_interruptible(timeout_jiffies(timeout))) timeout = sysctl_hung_task_timeout_secs; + if (atomic_xchg(&reset_hung_task, 0)) + continue; + check_hung_uninterruptible_tasks(timeout); } -- 2.20.1