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Commit 8b414521 authored by Marcelo Tosatti's avatar Marcelo Tosatti Committed by Gleb Natapov
Browse files

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: default avatarDon Zickus <dzickus@redhat.com>
Acked-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: default avatarGleb Natapov <gleb@redhat.com>
parent d63285e9

arch/x86/kernel/pvclock.c

+1 −0
Original line number Diff line number Diff line
@@ -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);

include/linux/sched.h

+8 −0
Original line number Diff line number Diff line
@@ -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")))

kernel/hung_task.c

+11 −0
Original line number Diff line number Diff line
@@ -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);

	}