time: Remove CONFIG_TIMER_STATS

Currently CONFIG_TIMER_STATS exposes process information across namespaces: kernel/time/timer_list.c print_timer(): SEQ_printf(m, ", %s/%d", tmp, timer->start_pid); /proc/timer_list: flar2#11: <0000000000000000>, hrtimer_wakeup, S:01, do_nanosleep, cron/2570 Given that the tracer can give the same information, this patch entirely removes CONFIG_TIMER_STATS. Change-Id: I5147c4c1b4319cdabbc6d635b0d63f701b24ac30 Suggested-by: Thomas Gleixner <[email protected]> Signed-off-by: Kees Cook <[email protected]> Acked-by: John Stultz <[email protected]> Cc: Nicolas Pitre <[email protected]> Cc: [email protected] Cc: Lai Jiangshan <[email protected]> Cc: Shuah Khan <[email protected]> Cc: Xing Gao <[email protected]> Cc: Jonathan Corbet <[email protected]> Cc: Jessica Frazelle <[email protected]> Cc: [email protected] Cc: Nicolas Iooss <[email protected]> Cc: "Paul E. McKenney" <[email protected]> Cc: Petr Mladek <[email protected]> Cc: Richard Cochran <[email protected]> Cc: Tejun Heo <[email protected]> Cc: Michal Marek <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Dmitry Vyukov <[email protected]> Cc: Oleg Nesterov <[email protected]> Cc: "Eric W. Biederman" <[email protected]> Cc: Olof Johansson <[email protected]> Cc: Andrew Morton <[email protected]> Cc: [email protected] Cc: Arjan van de Ven <[email protected]> Link: http://lkml.kernel.org/r/20170208192659.GA32582@beast Signed-off-by: Thomas Gleixner <[email protected]> haggertk: Backported to 3.4 Signed-off-by: Kevin F. Haggerty <[email protected]> Signed-off-by: D. Andrei Măceș <[email protected]>
airend · May 5, 2018 · 99ed638 · 99ed638
1 parent b248841
commit 99ed638
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diff --git a/Documentation/timers/00-INDEX b/Documentation/timers/00-INDEX
@@ -8,5 +8,3 @@ hpet_example.c
 	- sample hpet timer test program
 hrtimers.txt
 	- subsystem for high-resolution kernel timers
-timer_stats.txt
-	- timer usage statistics
diff --git a/Documentation/timers/timer_stats.txt b/Documentation/timers/timer_stats.txt
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
@@ -96,12 +96,6 @@ enum hrtimer_restart {
  * @function:	timer expiry callback function
  * @base:	pointer to the timer base (per cpu and per clock)
  * @state:	state information (See bit values above)
- * @start_site:	timer statistics field to store the site where the timer
- *		was started
- * @start_comm: timer statistics field to store the name of the process which
- *		started the timer
- * @start_pid: timer statistics field to store the pid of the task which
- *		started the timer
  *
  * The hrtimer structure must be initialized by hrtimer_init()
  */
@@ -111,11 +105,6 @@ struct hrtimer {
 	enum hrtimer_restart		(*function)(struct hrtimer *);
 	struct hrtimer_clock_base	*base;
 	unsigned long			state;
-#ifdef CONFIG_TIMER_STATS
-	int				start_pid;
-	void				*start_site;
-	char				start_comm[16];
-#endif
 };
 
 /**

diff --git a/include/linux/timer.h b/include/linux/timer.h
@@ -23,11 +23,6 @@ struct timer_list {
 
 	int slack;
 
-#ifdef CONFIG_TIMER_STATS
-	int start_pid;
-	void *start_site;
-	char start_comm[16];
-#endif
 #ifdef CONFIG_LOCKDEP
 	struct lockdep_map lockdep_map;
 #endif
@@ -229,49 +224,6 @@ extern void set_timer_slack(struct timer_list *time, int slack_hz);
  */
 extern unsigned long get_next_timer_interrupt(unsigned long now);
 
-/*
- * Timer-statistics info:
- */
-#ifdef CONFIG_TIMER_STATS
-
-extern int timer_stats_active;
-
-#define TIMER_STATS_FLAG_DEFERRABLE	0x1
-
-extern void init_timer_stats(void);
-
-extern void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
-				     void *timerf, char *comm,
-				     unsigned int timer_flag);
-
-extern void __timer_stats_timer_set_start_info(struct timer_list *timer,
-					       void *addr);
-
-static inline void timer_stats_timer_set_start_info(struct timer_list *timer)
-{
-	if (likely(!timer_stats_active))
-		return;
-	__timer_stats_timer_set_start_info(timer, __builtin_return_address(0));
-}
-
-static inline void timer_stats_timer_clear_start_info(struct timer_list *timer)
-{
-	timer->start_site = NULL;
-}
-#else
-static inline void init_timer_stats(void)
-{
-}
-
-static inline void timer_stats_timer_set_start_info(struct timer_list *timer)
-{
-}
-
-static inline void timer_stats_timer_clear_start_info(struct timer_list *timer)
-{
-}
-#endif
-
 extern void add_timer(struct timer_list *timer);
 
 extern int try_to_del_timer_sync(struct timer_list *timer);

diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
@@ -802,34 +802,6 @@ void hrtimers_resume(void)
 	clock_was_set_delayed();
 }
 
-static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)
-{
-#ifdef CONFIG_TIMER_STATS
-	if (timer->start_site)
-		return;
-	timer->start_site = __builtin_return_address(0);
-	memcpy(timer->start_comm, current->comm, TASK_COMM_LEN);
-	timer->start_pid = current->pid;
-#endif
-}
-
-static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer)
-{
-#ifdef CONFIG_TIMER_STATS
-	timer->start_site = NULL;
-#endif
-}
-
-static inline void timer_stats_account_hrtimer(struct hrtimer *timer)
-{
-#ifdef CONFIG_TIMER_STATS
-	if (likely(!timer_stats_active))
-		return;
-	timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
-				 timer->function, timer->start_comm, 0);
-#endif
-}
-
 /*
  * Counterpart to lock_hrtimer_base above:
  */
@@ -966,7 +938,6 @@ remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base)
 		 * rare case and less expensive than a smp call.
 		 */
 		debug_deactivate(timer);
-		timer_stats_hrtimer_clear_start_info(timer);
 		reprogram = base->cpu_base == &__get_cpu_var(hrtimer_bases);
 		/*
 		 * We must preserve the CALLBACK state flag here,
@@ -1012,8 +983,6 @@ int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
 
 	hrtimer_set_expires_range_ns(timer, tim, delta_ns);
 
-	timer_stats_hrtimer_set_start_info(timer);
-
 	leftmost = enqueue_hrtimer(timer, new_base);
 
 	/*
@@ -1202,12 +1171,6 @@ static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
 	base = hrtimer_clockid_to_base(clock_id);
 	timer->base = &cpu_base->clock_base[base];
 	timerqueue_init(&timer->node);
-
-#ifdef CONFIG_TIMER_STATS
-	timer->start_site = NULL;
-	timer->start_pid = -1;
-	memset(timer->start_comm, 0, TASK_COMM_LEN);
-#endif
 }
 
 /**
@@ -1255,7 +1218,6 @@ static void __run_hrtimer(struct hrtimer *timer, ktime_t *now)
 
 	debug_deactivate(timer);
 	__remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0);
-	timer_stats_account_hrtimer(timer);
 	fn = timer->function;
 
 	/*

diff --git a/kernel/time/Makefile b/kernel/time/Makefile
@@ -7,6 +7,5 @@ obj-$(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST)	+= tick-broadcast.o
 obj-$(CONFIG_GENERIC_SCHED_CLOCK)		+= sched_clock.o
 obj-$(CONFIG_TICK_ONESHOT)			+= tick-oneshot.o
 obj-$(CONFIG_TICK_ONESHOT)			+= tick-sched.o
-obj-$(CONFIG_TIMER_STATS)			+= timer_stats.o
 
 ccflags-y += -Idrivers/cpuidle
diff --git a/kernel/time/timer_list.c b/kernel/time/timer_list.c
@@ -50,21 +50,11 @@ static void
 print_timer(struct seq_file *m, struct hrtimer *taddr, struct hrtimer *timer,
 	    int idx, u64 now)
 {
-#ifdef CONFIG_TIMER_STATS
-	char tmp[TASK_COMM_LEN + 1];
-#endif
 	SEQ_printf(m, " #%d: ", idx);
 	print_name_offset(m, taddr);
 	SEQ_printf(m, ", ");
 	print_name_offset(m, timer->function);
 	SEQ_printf(m, ", S:%02lx", timer->state);
-#ifdef CONFIG_TIMER_STATS
-	SEQ_printf(m, ", ");
-	print_name_offset(m, timer->start_site);
-	memcpy(tmp, timer->start_comm, TASK_COMM_LEN);
-	tmp[TASK_COMM_LEN] = 0;
-	SEQ_printf(m, ", %s/%d", tmp, timer->start_pid);
-#endif
 	SEQ_printf(m, "\n");
 	SEQ_printf(m, " # expires at %Lu-%Lu nsecs [in %Ld to %Ld nsecs]\n",
 		(unsigned long long)ktime_to_ns(hrtimer_get_softexpires(timer)),