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Commit 2b022e3d authored by Xiao Guangrong's avatar Xiao Guangrong Committed by Thomas Gleixner
Browse files

timers: Add tracepoints for timer_list timers 

Add tracepoints which cover the timer life cycle. The tracepoints are
integrated with the already existing debug_object debug points as far
as possible.

Based on patches from 
Mathieu: http://marc.info/?l=linux-kernel&m=123791201816247&w=2
and 
Anton: http://marc.info/?l=linux-kernel&m=124331396919301&w=2



[ tglx: Fixed timeout value in timer_start tracepoint, massaged
  comments and made the printk's more readable ]

Signed-off-by: default avatarXiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Zhaolei <zhaolei@cn.fujitsu.com>
LKML-Reference: <4A7F8A9B.3040201@cn.fujitsu.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent f71bb0ac

include/trace/events/timer.h

0 → 100644
+137 −0
Original line number Diff line number Diff line 
#undef TRACE_SYSTEM

#define TRACE_SYSTEM timer



#if !defined(_TRACE_TIMER_H) || defined(TRACE_HEADER_MULTI_READ)

#define _TRACE_TIMER_H



#include <linux/tracepoint.h>

#include <linux/timer.h>



/**

 * timer_init - called when the timer is initialized

 * @timer:	pointer to struct timer_list

 */

TRACE_EVENT(timer_init,



	TP_PROTO(struct timer_list *timer),



	TP_ARGS(timer),



	TP_STRUCT__entry(

		__field( void *,	timer	)

	),



	TP_fast_assign(

		__entry->timer	= timer;

	),



	TP_printk("timer %p", __entry->timer)

);



/**

 * timer_start - called when the timer is started

 * @timer:	pointer to struct timer_list

 * @expires:	the timers expiry time

 */

TRACE_EVENT(timer_start,



	TP_PROTO(struct timer_list *timer, unsigned long expires),



	TP_ARGS(timer, expires),



	TP_STRUCT__entry(

		__field( void *,	timer		)

		__field( void *,	function	)

		__field( unsigned long,	expires		)

		__field( unsigned long,	now		)

	),



	TP_fast_assign(

		__entry->timer		= timer;

		__entry->function	= timer->function;

		__entry->expires	= expires;

		__entry->now		= jiffies;

	),



	TP_printk("timer %p: func %pf, expires %lu, timeout %ld",

		  __entry->timer, __entry->function, __entry->expires,

		  (long)__entry->expires - __entry->now)

);



/**

 * timer_expire_entry - called immediately before the timer callback

 * @timer:	pointer to struct timer_list

 *

 * Allows to determine the timer latency.

 */

TRACE_EVENT(timer_expire_entry,



	TP_PROTO(struct timer_list *timer),



	TP_ARGS(timer),



	TP_STRUCT__entry(

		__field( void *,	timer	)

		__field( unsigned long,	now	)

	),



	TP_fast_assign(

		__entry->timer		= timer;

		__entry->now		= jiffies;

	),



	TP_printk("timer %p: now %lu", __entry->timer, __entry->now)

);



/**

 * timer_expire_exit - called immediately after the timer callback returns

 * @timer:	pointer to struct timer_list

 *

 * When used in combination with the timer_expire_entry tracepoint we can

 * determine the runtime of the timer callback function.

 *

 * NOTE: Do NOT derefernce timer in TP_fast_assign. The pointer might

 * be invalid. We solely track the pointer.

 */

TRACE_EVENT(timer_expire_exit,



	TP_PROTO(struct timer_list *timer),



	TP_ARGS(timer),



	TP_STRUCT__entry(

		__field(void *,	timer	)

	),



	TP_fast_assign(

		__entry->timer	= timer;

	),



	TP_printk("timer %p", __entry->timer)

);



/**

 * timer_cancel - called when the timer is canceled

 * @timer:	pointer to struct timer_list

 */

TRACE_EVENT(timer_cancel,



	TP_PROTO(struct timer_list *timer),



	TP_ARGS(timer),



	TP_STRUCT__entry(

		__field( void *,	timer	)

	),



	TP_fast_assign(

		__entry->timer	= timer;

	),



	TP_printk("timer %p", __entry->timer)

);



#endif /*  _TRACE_TIMER_H */



/* This part must be outside protection */

#include <trace/define_trace.h>

kernel/timer.c

+28 −4
Original line number Diff line number Diff line
@@ -46,6 +46,9 @@ 
#include <asm/timex.h>

#include <asm/io.h>



#define CREATE_TRACE_POINTS

#include <trace/events/timer.h>



u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES;



EXPORT_SYMBOL(jiffies_64);
@@ -521,6 +524,25 @@ static inline void debug_timer_activate(struct timer_list *timer) { } 
static inline void debug_timer_deactivate(struct timer_list *timer) { }

#endif



static inline void debug_init(struct timer_list *timer)

{

	debug_timer_init(timer);

	trace_timer_init(timer);

}



static inline void

debug_activate(struct timer_list *timer, unsigned long expires)

{

	debug_timer_activate(timer);

	trace_timer_start(timer, expires);

}



static inline void debug_deactivate(struct timer_list *timer)

{

	debug_timer_deactivate(timer);

	trace_timer_cancel(timer);

}



static void __init_timer(struct timer_list *timer,

			 const char *name,

			 struct lock_class_key *key)
@@ -549,7 +571,7 @@ void init_timer_key(struct timer_list *timer, 
		    const char *name,

		    struct lock_class_key *key)

{

	debug_timer_init(timer);

	debug_init(timer);

	__init_timer(timer, name, key);

}

EXPORT_SYMBOL(init_timer_key);
@@ -568,7 +590,7 @@ static inline void detach_timer(struct timer_list *timer, 
{

	struct list_head *entry = &timer->entry;



	debug_timer_deactivate(timer);

	debug_deactivate(timer);



	__list_del(entry->prev, entry->next);

	if (clear_pending)
@@ -632,7 +654,7 @@ __mod_timer(struct timer_list *timer, unsigned long expires, 
			goto out_unlock;

	}



	debug_timer_activate(timer);

	debug_activate(timer, expires);



	new_base = __get_cpu_var(tvec_bases);
@@ -787,7 +809,7 @@ void add_timer_on(struct timer_list *timer, int cpu) 
	BUG_ON(timer_pending(timer) || !timer->function);

	spin_lock_irqsave(&base->lock, flags);

	timer_set_base(timer, base);

	debug_timer_activate(timer);

	debug_activate(timer, timer->expires);

	if (time_before(timer->expires, base->next_timer) &&

	    !tbase_get_deferrable(timer->base))

		base->next_timer = timer->expires;
@@ -1000,7 +1022,9 @@ static inline void __run_timers(struct tvec_base *base) 
				 */

				lock_map_acquire(&lockdep_map);



				trace_timer_expire_entry(timer);

				fn(data);

				trace_timer_expire_exit(timer);



				lock_map_release(&lockdep_map);