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Commit c74441a1 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

timer: Stats: Simplify the flags handling 



Simplify the handling of the flag storage for the timer statistics. No
intermediate storage anymore. Just hand over the flags field.

I left the printout of 'deferrable' for now because changing this
would be an ABI update and I have no idea how strong people feel about
that. OTOH, I wonder whether we should kill the whole timer stats
stuff because all of that information can be retrieved via ftrace/perf
as well.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Joonwoo Park <joonwoop@codeaurora.org>
Cc: Wenbo Wang <wenbo.wang@memblaze.com>
Link: http://lkml.kernel.org/r/20150526224512.046626248@linutronix.de


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 0eeda71b

include/linux/timer.h

+1 −4
Original line number Diff line number Diff line
@@ -188,13 +188,10 @@ extern void set_timer_slack(struct timer_list *time, int slack_hz); 


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);

				     void *timerf, char *comm, u32 flags);



extern void __timer_stats_timer_set_start_info(struct timer_list *timer,

					       void *addr);

kernel/time/timer.c

+2 −5
Original line number Diff line number Diff line
@@ -404,15 +404,12 @@ void __timer_stats_timer_set_start_info(struct timer_list *timer, void *addr) 


static void timer_stats_account_timer(struct timer_list *timer)

{

	unsigned int flag = 0;



	if (likely(!timer->start_site))

		return;

	if (unlikely(timer->flags & TIMER_DEFERRABLE))

		flag |= TIMER_STATS_FLAG_DEFERRABLE;



	timer_stats_update_stats(timer, timer->start_pid, timer->start_site,

				 timer->function, timer->start_comm, flag);

				 timer->function, timer->start_comm,

				 timer->flags);

}



#else

kernel/time/timer_stats.c

+5 −5
Original line number Diff line number Diff line
@@ -68,7 +68,7 @@ struct entry { 
	 * Number of timeout events:

	 */

	unsigned long		count;

	unsigned int		timer_flag;

	u32			flags;



	/*

	 * We save the command-line string to preserve
@@ -227,13 +227,13 @@ static struct entry *tstat_lookup(struct entry *entry, char *comm) 
 * @startf:	pointer to the function which did the timer setup

 * @timerf:	pointer to the timer callback function of the timer

 * @comm:	name of the process which set up the timer

 * @tflags:	The flags field of the timer

 *

 * When the timer is already registered, then the event counter is

 * incremented. Otherwise the timer is registered in a free slot.

 */

void timer_stats_update_stats(void *timer, pid_t pid, void *startf,

			      void *timerf, char *comm,

			      unsigned int timer_flag)

			      void *timerf, char *comm, u32 tflags)

{

	/*

	 * It doesn't matter which lock we take:
@@ -251,7 +251,7 @@ void timer_stats_update_stats(void *timer, pid_t pid, void *startf, 
	input.start_func = startf;

	input.expire_func = timerf;

	input.pid = pid;

	input.timer_flag = timer_flag;

	input.flags = tflags;



	raw_spin_lock_irqsave(lock, flags);

	if (!timer_stats_active)
@@ -306,7 +306,7 @@ static int tstats_show(struct seq_file *m, void *v) 


	for (i = 0; i < nr_entries; i++) {

		entry = entries + i;

		if (entry->timer_flag & TIMER_STATS_FLAG_DEFERRABLE) {

		if (entry->flags & TIMER_DEFERRABLE) {

			seq_printf(m, "%4luD, %5d %-16s ",

				entry->count, entry->pid, entry->comm);

		} else {