LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Thomas Gleixner <tglx@linutronix.de>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: [GIT pull] time(r) fixes for .25
Date: Sun, 9 Mar 2008 09:07:24 +0100 (CET)	[thread overview]
Message-ID: <alpine.LFD.1.00.0803090857480.3099@apollo.tec.linutronix.de> (raw)

Linus,

please pull time(r) related fixes from:

  ssh://master.kernel.org/pub/scm/linux/kernel/git/tglx/linux-2.6-hrt.git master

Thanks,
	tglx

David Howells (1):
      ntp: use unsigned input for do_div()

Karsten Wiese (1):
      time: don't touch an offlined CPU's ts->tick_stopped in tick_cancel_sched_timer()

Roman Zippel (1):
      time: remove obsolete CLOCK_TICK_ADJUST

Segher Boessenkool (1):
      time: prevent the loop in timespec_add_ns() from being optimised away

 include/linux/time.h      |    4 ++++
 include/linux/timex.h     |    9 +--------
 kernel/time/ntp.c         |   23 +++++++++++++++++------
 kernel/time/tick-sched.c  |    2 +-
 kernel/time/timekeeping.c |    6 ++----

 5 files changed, 25 insertions(+), 19 deletions(-)
diff --git a/include/linux/time.h b/include/linux/time.h
index 2091a19..d32ef0a 100644
--- a/include/linux/time.h
+++ b/include/linux/time.h
@@ -174,6 +174,10 @@ static inline void timespec_add_ns(struct timespec *a, u64 ns)
 {
 	ns += a->tv_nsec;
 	while(unlikely(ns >= NSEC_PER_SEC)) {
+		/* The following asm() prevents the compiler from
+		 * optimising this loop into a modulo operation.  */
+		asm("" : "+r"(ns));
+
 		ns -= NSEC_PER_SEC;
 		a->tv_sec++;
 	}
diff --git a/include/linux/timex.h b/include/linux/timex.h
index c3f3747..8ea3e71 100644
--- a/include/linux/timex.h
+++ b/include/linux/timex.h
@@ -232,14 +232,7 @@ static inline int ntp_synced(void)
 #else
 #define NTP_INTERVAL_FREQ  (HZ)
 #endif
-
-#define CLOCK_TICK_OVERFLOW	(LATCH * HZ - CLOCK_TICK_RATE)
-#define CLOCK_TICK_ADJUST	(((s64)CLOCK_TICK_OVERFLOW * NSEC_PER_SEC) / \
-					(s64)CLOCK_TICK_RATE)
-
-/* Because using NSEC_PER_SEC would be too easy */
-#define NTP_INTERVAL_LENGTH ((((s64)TICK_USEC * NSEC_PER_USEC * USER_HZ) + \
-			      CLOCK_TICK_ADJUST) / NTP_INTERVAL_FREQ)
+#define NTP_INTERVAL_LENGTH (NSEC_PER_SEC/NTP_INTERVAL_FREQ)
 
 /* Returns how long ticks are at present, in ns / 2^(SHIFT_SCALE-10). */
 extern u64 current_tick_length(void);
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index c88b591..5fd9b94 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -42,12 +42,13 @@ long time_esterror = NTP_PHASE_LIMIT;	/* estimated error (us)		*/
 long time_freq;				/* frequency offset (scaled ppm)*/
 static long time_reftime;		/* time at last adjustment (s)	*/
 long time_adjust;
+static long ntp_tick_adj;
 
 static void ntp_update_frequency(void)
 {
 	u64 second_length = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ)
 				<< TICK_LENGTH_SHIFT;
-	second_length += (s64)CLOCK_TICK_ADJUST << TICK_LENGTH_SHIFT;
+	second_length += (s64)ntp_tick_adj << TICK_LENGTH_SHIFT;
 	second_length += (s64)time_freq << (TICK_LENGTH_SHIFT - SHIFT_NSEC);
 
 	tick_length_base = second_length;
@@ -342,14 +343,16 @@ int do_adjtimex(struct timex *txc)
 		    freq_adj = shift_right(freq_adj, time_constant * 2 +
 					   (SHIFT_PLL + 2) * 2 - SHIFT_NSEC);
 		    if (mtemp >= MINSEC && (time_status & STA_FLL || mtemp > MAXSEC)) {
+			u64 utemp64;
 			temp64 = time_offset << (SHIFT_NSEC - SHIFT_FLL);
 			if (time_offset < 0) {
-			    temp64 = -temp64;
-			    do_div(temp64, mtemp);
-			    freq_adj -= temp64;
+			    utemp64 = -temp64;
+			    do_div(utemp64, mtemp);
+			    freq_adj -= utemp64;
 			} else {
-			    do_div(temp64, mtemp);
-			    freq_adj += temp64;
+			    utemp64 = temp64;
+			    do_div(utemp64, mtemp);
+			    freq_adj += utemp64;
 			}
 		    }
 		    freq_adj += time_freq;
@@ -400,3 +403,11 @@ leave:	if ((time_status & (STA_UNSYNC|STA_CLOCKERR)) != 0)
 	notify_cmos_timer();
 	return(result);
 }
+
+static int __init ntp_tick_adj_setup(char *str)
+{
+	ntp_tick_adj = simple_strtol(str, NULL, 0);
+	return 1;
+}
+
+__setup("ntp_tick_adj=", ntp_tick_adj_setup);
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 2968298..686da82 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -640,7 +640,7 @@ void tick_cancel_sched_timer(int cpu)
 
 	if (ts->sched_timer.base)
 		hrtimer_cancel(&ts->sched_timer);
-	ts->tick_stopped = 0;
+
 	ts->nohz_mode = NOHZ_MODE_INACTIVE;
 }
 #endif /* HIGH_RES_TIMERS */
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 1af9fb0..671af61 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -187,8 +187,7 @@ static void change_clocksource(void)
 
 	clock->error = 0;
 	clock->xtime_nsec = 0;
-	clocksource_calculate_interval(clock,
-		(unsigned long)(current_tick_length()>>TICK_LENGTH_SHIFT));
+	clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH);
 
 	tick_clock_notify();
 
@@ -245,8 +244,7 @@ void __init timekeeping_init(void)
 	ntp_clear();
 
 	clock = clocksource_get_next();
-	clocksource_calculate_interval(clock,
-		(unsigned long)(current_tick_length()>>TICK_LENGTH_SHIFT));
+	clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH);
 	clock->cycle_last = clocksource_read(clock);
 
 	xtime.tv_sec = sec;

             reply	other threads:[~2008-03-09  8:08 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-03-09  8:07 Thomas Gleixner [this message]
2008-03-10 16:44 ` Pavel Machek
2008-03-10 19:38   ` Adrian Bunk

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=alpine.LFD.1.00.0803090857480.3099@apollo.tec.linutronix.de \
    --to=tglx@linutronix.de \
    --cc=linux-kernel@vger.kernel.org \
    --cc=torvalds@linux-foundation.org \
    --subject='Re: [GIT pull] time(r) fixes for .25' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).