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From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Paul McKenney <paulmck@linux.vnet.ibm.com>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Eric Dumazet <edumazet@google.com>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	John Stultz <john.stultz@linaro.org>,
	Joonwoo Park <joonwoop@codeaurora.org>,
	Wenbo Wang <wenbo.wang@memblaze.com>
Subject: [patch 5/7] timer: stats: Simplify the flags handling
Date: Tue, 26 May 2015 22:50:31 -0000	[thread overview]
Message-ID: <20150526224512.046626248@linutronix.de> (raw)
In-Reply-To: 20150526210723.245729529@linutronix.de

[-- Attachment #1: timer-stats-simplify-flags-handling.patch --]
[-- Type: text/plain, Size: 3575 bytes --]

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: Thomas Gleixner <tglx@linutronix.de>
---
 include/linux/timer.h     |    5 +----
 kernel/time/timer.c       |    7 ++-----
 kernel/time/timer_stats.c |   10 +++++-----
 3 files changed, 8 insertions(+), 14 deletions(-)

Index: tip/include/linux/timer.h
===================================================================
--- tip.orig/include/linux/timer.h
+++ tip/include/linux/timer.h
@@ -188,13 +188,10 @@ extern void set_timer_slack(struct timer
 
 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);
Index: tip/kernel/time/timer.c
===================================================================
--- tip.orig/kernel/time/timer.c
+++ tip/kernel/time/timer.c
@@ -418,15 +418,12 @@ void __timer_stats_timer_set_start_info(
 
 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
Index: tip/kernel/time/timer_stats.c
===================================================================
--- tip.orig/kernel/time/timer_stats.c
+++ tip/kernel/time/timer_stats.c
@@ -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
  * @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 *time
 	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 *
 
 	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 {



  parent reply	other threads:[~2015-05-26 22:51 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-05-26 22:50 [patch 0/7] timers: Footprint diet and NOHZ overhead mitigation Thomas Gleixner
2015-05-26 22:50 ` [patch 1/7] timers: Sanitize catchup_timer_jiffies() usage Thomas Gleixner
2015-05-27  5:39   ` Viresh Kumar
2015-06-19 13:22   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-05-26 22:50 ` [patch 2/7] timer: Remove FIFO guarantee Thomas Gleixner
2015-05-27  9:11   ` Viresh Kumar
2015-06-19 13:22   ` [tip:timers/core] timer: Remove FIFO "guarantee" tip-bot for Thomas Gleixner
2015-05-26 22:50 ` [patch 3/7] timer: Use hlist for the timer wheel hash buckets Thomas Gleixner
2015-05-27  9:13   ` Viresh Kumar
2015-06-19 13:23   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-05-26 22:50 ` [patch 4/7] timer: Replace timer base by a cpu index Thomas Gleixner
2015-05-27  9:22   ` Viresh Kumar
2015-05-27 12:09     ` Peter Zijlstra
2015-06-02 13:58       ` Thomas Gleixner
2015-06-19 13:23   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-06-27  9:55   ` [PATCH] timer: Fix unsafe cpu variable access in migrate_timers Jan Kiszka
2015-06-27 11:00     ` Borislav Petkov
2015-06-27 11:19       ` Jan Kiszka
2015-06-27 11:25         ` Borislav Petkov
2015-05-26 22:50 ` Thomas Gleixner [this message]
2015-06-19 13:23   ` [tip:timers/core] timer: Stats: Simplify the flags handling tip-bot for Thomas Gleixner
2015-05-26 22:50 ` [patch 6/7] timer: Reduce timer migration overhead if disabled Thomas Gleixner
2015-06-19 13:23   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-05-26 22:50 ` [patch 7/7] timer: Minimize nohz off overhead Thomas Gleixner
2015-06-19 13:24   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-05-27 14:53 ` [patch 0/7] timers: Footprint diet and NOHZ overhead mitigation Eric Dumazet
2015-06-02 13:58   ` Thomas Gleixner

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