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From: John Stultz <john.stultz@linaro.org>
To: LKML <linux-kernel@vger.kernel.org>
Cc: John Stultz <john.stultz@linaro.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Eric Dumazet <eric.dumazet@gmail.com>,
	Richard Cochran <richardcochran@gmail.com>
Subject: [PATCH 10/16] time: Remove most of xtime_lock usage in timekeeping.c
Date: Mon, 14 Nov 2011 20:04:00 -0800	[thread overview]
Message-ID: <1321329846-14755-11-git-send-email-john.stultz@linaro.org> (raw)
In-Reply-To: <1321329846-14755-1-git-send-email-john.stultz@linaro.org>

Now that ntp.c's locking is reworked, we can remove most
of the xtime_lock usage in timekeeping.c

The remaining xtime_lock presence is really for jiffies access
and the global load calculation.

CC: Thomas Gleixner <tglx@linutronix.de>
CC: Eric Dumazet <eric.dumazet@gmail.com>
CC: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
 kernel/time/timekeeping.c |   44 +++++++++++++++-----------------------------
 1 files changed, 15 insertions(+), 29 deletions(-)

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index f92e636..810b974 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -172,7 +172,6 @@ static inline s64 timekeeping_get_ns_raw(void)
 	return clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift);
 }
 
-/* must hold xtime_lock */
 void timekeeping_leap_insert(int leapsecond)
 {
 	unsigned long flags;
@@ -368,13 +367,12 @@ EXPORT_SYMBOL(do_gettimeofday);
 int do_settimeofday(const struct timespec *tv)
 {
 	struct timespec ts_delta;
-	unsigned long flags1,flags2;
+	unsigned long flags;
 
 	if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
 		return -EINVAL;
 
-	write_seqlock_irqsave(&xtime_lock, flags1);
-	write_seqlock_irqsave(&timekeeper.lock, flags2);
+	write_seqlock_irqsave(&timekeeper.lock, flags);
 
 	timekeeping_forward_now();
 
@@ -391,8 +389,7 @@ int do_settimeofday(const struct timespec *tv)
 	update_vsyscall(&timekeeper.xtime, &timekeeper.wall_to_monotonic,
 			timekeeper.clock, timekeeper.mult);
 
-	write_sequnlock_irqrestore(&timekeeper.lock, flags2);
-	write_sequnlock_irqrestore(&xtime_lock, flags1);
+	write_sequnlock_irqrestore(&timekeeper.lock, flags);
 
 	/* signal hrtimers about time change */
 	clock_was_set();
@@ -411,13 +408,12 @@ EXPORT_SYMBOL(do_settimeofday);
  */
 int timekeeping_inject_offset(struct timespec *ts)
 {
-	unsigned long flags1,flags2;
+	unsigned long flags;
 
 	if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)
 		return -EINVAL;
 
-	write_seqlock_irqsave(&xtime_lock, flags1);
-	write_seqlock_irqsave(&timekeeper.lock, flags2);
+	write_seqlock_irqsave(&timekeeper.lock, flags);
 
 	timekeeping_forward_now();
 
@@ -431,8 +427,7 @@ int timekeeping_inject_offset(struct timespec *ts)
 	update_vsyscall(&timekeeper.xtime, &timekeeper.wall_to_monotonic,
 			timekeeper.clock, timekeeper.mult);
 
-	write_sequnlock_irqrestore(&timekeeper.lock, flags2);
-	write_sequnlock_irqrestore(&xtime_lock, flags1);
+	write_sequnlock_irqrestore(&timekeeper.lock, flags);
 
 	/* signal hrtimers about time change */
 	clock_was_set();
@@ -594,9 +589,7 @@ void __init timekeeping_init(void)
 
 	seqlock_init(&timekeeper.lock);
 
-	write_seqlock_irqsave(&xtime_lock, flags);
 	ntp_init();
-	write_sequnlock_irqrestore(&xtime_lock, flags);
 
 	write_seqlock_irqsave(&timekeeper.lock, flags);
 	clock = clocksource_default_clock();
@@ -657,7 +650,7 @@ static void __timekeeping_inject_sleeptime(struct timespec *delta)
  */
 void timekeeping_inject_sleeptime(struct timespec *delta)
 {
-	unsigned long flags1,flags2;
+	unsigned long flags;
 	struct timespec ts;
 
 	/* Make sure we don't set the clock twice */
@@ -665,8 +658,7 @@ void timekeeping_inject_sleeptime(struct timespec *delta)
 	if (!(ts.tv_sec == 0 && ts.tv_nsec == 0))
 		return;
 
-	write_seqlock_irqsave(&xtime_lock, flags1);
-	write_seqlock_irqsave(&timekeeper.lock, flags2);
+	write_seqlock_irqsave(&timekeeper.lock, flags);
 
 	timekeeping_forward_now();
 
@@ -677,8 +669,7 @@ void timekeeping_inject_sleeptime(struct timespec *delta)
 	update_vsyscall(&timekeeper.xtime, &timekeeper.wall_to_monotonic,
 			timekeeper.clock, timekeeper.mult);
 
-	write_sequnlock_irqrestore(&timekeeper.lock, flags2);
-	write_sequnlock_irqrestore(&xtime_lock, flags1);
+	write_sequnlock_irqrestore(&timekeeper.lock, flags);
 
 	/* signal hrtimers about time change */
 	clock_was_set();
@@ -694,15 +685,14 @@ void timekeeping_inject_sleeptime(struct timespec *delta)
  */
 static void timekeeping_resume(void)
 {
-	unsigned long flags1,flags2;
+	unsigned long flags;
 	struct timespec ts;
 
 	read_persistent_clock(&ts);
 
 	clocksource_resume();
 
-	write_seqlock_irqsave(&xtime_lock, flags1);
-	write_seqlock_irqsave(&timekeeper.lock, flags2);
+	write_seqlock_irqsave(&timekeeper.lock, flags);
 
 	if (timespec_compare(&ts, &timekeeping_suspend_time) > 0) {
 		ts = timespec_sub(ts, timekeeping_suspend_time);
@@ -712,8 +702,7 @@ static void timekeeping_resume(void)
 	timekeeper.clock->cycle_last = timekeeper.clock->read(timekeeper.clock);
 	timekeeper.ntp_error = 0;
 	timekeeping_suspended = 0;
-	write_sequnlock_irqrestore(&timekeeper.lock, flags2);
-	write_sequnlock_irqrestore(&xtime_lock, flags1);
+	write_sequnlock_irqrestore(&timekeeper.lock, flags);
 
 	touch_softlockup_watchdog();
 
@@ -725,14 +714,13 @@ static void timekeeping_resume(void)
 
 static int timekeeping_suspend(void)
 {
-	unsigned long flags1,flags2;
+	unsigned long flags;
 	struct timespec		delta, delta_delta;
 	static struct timespec	old_delta;
 
 	read_persistent_clock(&timekeeping_suspend_time);
 
-	write_seqlock_irqsave(&xtime_lock, flags1);
-	write_seqlock_irqsave(&timekeeper.lock, flags2);
+	write_seqlock_irqsave(&timekeeper.lock, flags);
 	timekeeping_forward_now();
 	timekeeping_suspended = 1;
 
@@ -755,8 +743,7 @@ static int timekeeping_suspend(void)
 		timekeeping_suspend_time =
 			timespec_add(timekeeping_suspend_time, delta_delta);
 	}
-	write_sequnlock_irqrestore(&timekeeper.lock, flags2);
-	write_sequnlock_irqrestore(&xtime_lock, flags1);
+	write_sequnlock_irqrestore(&timekeeper.lock, flags);
 
 	clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL);
 	clocksource_suspend();
@@ -916,7 +903,6 @@ static cycle_t logarithmic_accumulation(cycle_t offset, int shift)
 /**
  * update_wall_time - Uses the current clocksource to increment the wall time
  *
- * Called from the timer interrupt, must hold a write on xtime_lock.
  */
 static void update_wall_time(void)
 {
-- 
1.7.3.2.146.gca209


  parent reply	other threads:[~2011-11-15  4:04 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-11-15  4:03 [PATCH 00/16] Timekeeping cleanups and locking changes John Stultz
2011-11-15  4:03 ` [PATCH 01/16] time: Move total_sleep_time into the timekeeper structure John Stultz
2011-11-15  4:03 ` [PATCH 02/16] time: Move wall_to_monotonic " John Stultz
2011-11-15  4:03 ` [PATCH 03/16] time: Move xtime into timekeeeper structure John Stultz
2011-11-15  4:03 ` [PATCH 04/16] time: Move raw_time into timekeeper structure John Stultz
2011-11-15  4:03 ` [PATCH 05/16] time: Cleanup global variables and move them to the top John Stultz
2011-11-15  4:03 ` [PATCH 06/16] time: Add timekeeper lock John Stultz
2011-11-15  4:03 ` [PATCH 07/16] ntp: Cleanup timex.h John Stultz
2011-11-15  4:03 ` [PATCH 08/16] ntp: Access tick_length variable via ntp_tick_length() John Stultz
2011-11-15  4:03 ` [PATCH 09/16] ntp: Add ntp_lock to replace xtime_locking John Stultz
2011-11-15  4:04 ` John Stultz [this message]
2011-11-15  4:04 ` [PATCH 11/16] time: Reorder so the hot data is together John Stultz
2011-11-15  4:04 ` [PATCH 12/16] time: Move common updates to a function John Stultz
2011-11-15  4:04 ` [PATCH 13/16] time: Condense timekeeper.xtime into xtime_sec John Stultz
2011-11-15  4:04 ` [PATCH 14/16] time: Rework timekeeping functions to take timekeeper ptr as argument John Stultz
2011-11-15  4:04 ` [PATCH 15/16] time: Update tiemkeeper structure using a local shadow John Stultz
2011-11-17 22:03   ` John Stultz
2011-11-15  4:04 ` [PATCH 16/16] time: Rework update_vsyscall to pass timekeeper John Stultz

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