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authorLinus Torvalds <torvalds@linux-foundation.org>2012-03-29 14:16:48 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-03-29 14:16:48 -0700
commitbcd550745fc54f789c14e7526e0633222c505faa (patch)
treec3fe11a6503b7ffdd4406a9fece5c40b3e2a3f6d /kernel/time
parent93f378883cecb9dcb2cf5b51d9d24175906659da (diff)
parent646783a389828e76e813f50791f7999429c821bc (diff)
Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer core updates from Thomas Gleixner. * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: ia64: vsyscall: Add missing paranthesis alarmtimer: Don't call rtc_timer_init() when CONFIG_RTC_CLASS=n x86: vdso: Put declaration before code x86-64: Inline vdso clock_gettime helpers x86-64: Simplify and optimize vdso clock_gettime monotonic variants kernel-time: fix s/then/than/ spelling errors time: remove no_sync_cmos_clock time: Avoid scary backtraces when warning of > 11% adj alarmtimer: Make sure we initialize the rtctimer ntp: Fix leap-second hrtimer livelock x86, tsc: Skip refined tsc calibration on systems with reliable TSC rtc: Provide flag for rtc devices that don't support UIE ia64: vsyscall: Use seqcount instead of seqlock x86: vdso: Use seqcount instead of seqlock x86: vdso: Remove bogus locking in update_vsyscall_tz() time: Remove bogus comments time: Fix change_clocksource locking time: x86: Fix race switching from vsyscall to non-vsyscall clock
Diffstat (limited to 'kernel/time')
-rw-r--r--kernel/time/alarmtimer.c8
-rw-r--r--kernel/time/clocksource.c2
-rw-r--r--kernel/time/ntp.c134
-rw-r--r--kernel/time/timekeeping.c51
4 files changed, 77 insertions, 118 deletions
diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index 8a46f5d64504..8a538c55fc7b 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -96,6 +96,11 @@ static int alarmtimer_rtc_add_device(struct device *dev,
return 0;
}
+static inline void alarmtimer_rtc_timer_init(void)
+{
+ rtc_timer_init(&rtctimer, NULL, NULL);
+}
+
static struct class_interface alarmtimer_rtc_interface = {
.add_dev = &alarmtimer_rtc_add_device,
};
@@ -117,6 +122,7 @@ static inline struct rtc_device *alarmtimer_get_rtcdev(void)
#define rtcdev (NULL)
static inline int alarmtimer_rtc_interface_setup(void) { return 0; }
static inline void alarmtimer_rtc_interface_remove(void) { }
+static inline void alarmtimer_rtc_timer_init(void) { }
#endif
/**
@@ -783,6 +789,8 @@ static int __init alarmtimer_init(void)
.nsleep = alarm_timer_nsleep,
};
+ alarmtimer_rtc_timer_init();
+
posix_timers_register_clock(CLOCK_REALTIME_ALARM, &alarm_clock);
posix_timers_register_clock(CLOCK_BOOTTIME_ALARM, &alarm_clock);
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index a45ca167ab24..c9583382141a 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -500,7 +500,7 @@ static u32 clocksource_max_adjustment(struct clocksource *cs)
{
u64 ret;
/*
- * We won't try to correct for more then 11% adjustments (110,000 ppm),
+ * We won't try to correct for more than 11% adjustments (110,000 ppm),
*/
ret = (u64)cs->mult * 11;
do_div(ret,100);
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 6e039b144daf..f03fd83b170b 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -34,8 +34,6 @@ unsigned long tick_nsec;
static u64 tick_length;
static u64 tick_length_base;
-static struct hrtimer leap_timer;
-
#define MAX_TICKADJ 500LL /* usecs */
#define MAX_TICKADJ_SCALED \
(((MAX_TICKADJ * NSEC_PER_USEC) << NTP_SCALE_SHIFT) / NTP_INTERVAL_FREQ)
@@ -381,70 +379,63 @@ u64 ntp_tick_length(void)
/*
- * Leap second processing. If in leap-insert state at the end of the
- * day, the system clock is set back one second; if in leap-delete
- * state, the system clock is set ahead one second.
+ * this routine handles the overflow of the microsecond field
+ *
+ * The tricky bits of code to handle the accurate clock support
+ * were provided by Dave Mills (Mills@UDEL.EDU) of NTP fame.
+ * They were originally developed for SUN and DEC kernels.
+ * All the kudos should go to Dave for this stuff.
+ *
+ * Also handles leap second processing, and returns leap offset
*/
-static enum hrtimer_restart ntp_leap_second(struct hrtimer *timer)
+int second_overflow(unsigned long secs)
{
- enum hrtimer_restart res = HRTIMER_NORESTART;
- unsigned long flags;
+ s64 delta;
int leap = 0;
+ unsigned long flags;
spin_lock_irqsave(&ntp_lock, flags);
+
+ /*
+ * Leap second processing. If in leap-insert state at the end of the
+ * day, the system clock is set back one second; if in leap-delete
+ * state, the system clock is set ahead one second.
+ */
switch (time_state) {
case TIME_OK:
+ if (time_status & STA_INS)
+ time_state = TIME_INS;
+ else if (time_status & STA_DEL)
+ time_state = TIME_DEL;
break;
case TIME_INS:
- leap = -1;
- time_state = TIME_OOP;
- printk(KERN_NOTICE
- "Clock: inserting leap second 23:59:60 UTC\n");
- hrtimer_add_expires_ns(&leap_timer, NSEC_PER_SEC);
- res = HRTIMER_RESTART;
+ if (secs % 86400 == 0) {
+ leap = -1;
+ time_state = TIME_OOP;
+ printk(KERN_NOTICE
+ "Clock: inserting leap second 23:59:60 UTC\n");
+ }
break;
case TIME_DEL:
- leap = 1;
- time_tai--;
- time_state = TIME_WAIT;
- printk(KERN_NOTICE
- "Clock: deleting leap second 23:59:59 UTC\n");
+ if ((secs + 1) % 86400 == 0) {
+ leap = 1;
+ time_tai--;
+ time_state = TIME_WAIT;
+ printk(KERN_NOTICE
+ "Clock: deleting leap second 23:59:59 UTC\n");
+ }
break;
case TIME_OOP:
time_tai++;
time_state = TIME_WAIT;
- /* fall through */
+ break;
+
case TIME_WAIT:
if (!(time_status & (STA_INS | STA_DEL)))
time_state = TIME_OK;
break;
}
- spin_unlock_irqrestore(&ntp_lock, flags);
- /*
- * We have to call this outside of the ntp_lock to keep
- * the proper locking hierarchy
- */
- if (leap)
- timekeeping_leap_insert(leap);
-
- return res;
-}
-
-/*
- * this routine handles the overflow of the microsecond field
- *
- * The tricky bits of code to handle the accurate clock support
- * were provided by Dave Mills (Mills@UDEL.EDU) of NTP fame.
- * They were originally developed for SUN and DEC kernels.
- * All the kudos should go to Dave for this stuff.
- */
-void second_overflow(void)
-{
- s64 delta;
- unsigned long flags;
-
- spin_lock_irqsave(&ntp_lock, flags);
/* Bump the maxerror field */
time_maxerror += MAXFREQ / NSEC_PER_USEC;
@@ -481,15 +472,17 @@ void second_overflow(void)
tick_length += (s64)(time_adjust * NSEC_PER_USEC / NTP_INTERVAL_FREQ)
<< NTP_SCALE_SHIFT;
time_adjust = 0;
+
+
+
out:
spin_unlock_irqrestore(&ntp_lock, flags);
+
+ return leap;
}
#ifdef CONFIG_GENERIC_CMOS_UPDATE
-/* Disable the cmos update - used by virtualization and embedded */
-int no_sync_cmos_clock __read_mostly;
-
static void sync_cmos_clock(struct work_struct *work);
static DECLARE_DELAYED_WORK(sync_cmos_work, sync_cmos_clock);
@@ -536,35 +529,13 @@ static void sync_cmos_clock(struct work_struct *work)
static void notify_cmos_timer(void)
{
- if (!no_sync_cmos_clock)
- schedule_delayed_work(&sync_cmos_work, 0);
+ schedule_delayed_work(&sync_cmos_work, 0);
}
#else
static inline void notify_cmos_timer(void) { }
#endif
-/*
- * Start the leap seconds timer:
- */
-static inline void ntp_start_leap_timer(struct timespec *ts)
-{
- long now = ts->tv_sec;
-
- if (time_status & STA_INS) {
- time_state = TIME_INS;
- now += 86400 - now % 86400;
- hrtimer_start(&leap_timer, ktime_set(now, 0), HRTIMER_MODE_ABS);
-
- return;
- }
-
- if (time_status & STA_DEL) {
- time_state = TIME_DEL;
- now += 86400 - (now + 1) % 86400;
- hrtimer_start(&leap_timer, ktime_set(now, 0), HRTIMER_MODE_ABS);
- }
-}
/*
* Propagate a new txc->status value into the NTP state:
@@ -589,22 +560,6 @@ static inline void process_adj_status(struct timex *txc, struct timespec *ts)
time_status &= STA_RONLY;
time_status |= txc->status & ~STA_RONLY;
- switch (time_state) {
- case TIME_OK:
- ntp_start_leap_timer(ts);
- break;
- case TIME_INS:
- case TIME_DEL:
- time_state = TIME_OK;
- ntp_start_leap_timer(ts);
- case TIME_WAIT:
- if (!(time_status & (STA_INS | STA_DEL)))
- time_state = TIME_OK;
- break;
- case TIME_OOP:
- hrtimer_restart(&leap_timer);
- break;
- }
}
/*
* Called with the xtime lock held, so we can access and modify
@@ -686,9 +641,6 @@ int do_adjtimex(struct timex *txc)
(txc->tick < 900000/USER_HZ ||
txc->tick > 1100000/USER_HZ))
return -EINVAL;
-
- if (txc->modes & ADJ_STATUS && time_state != TIME_OK)
- hrtimer_cancel(&leap_timer);
}
if (txc->modes & ADJ_SETOFFSET) {
@@ -1010,6 +962,4 @@ __setup("ntp_tick_adj=", ntp_tick_adj_setup);
void __init ntp_init(void)
{
ntp_clear();
- hrtimer_init(&leap_timer, CLOCK_REALTIME, HRTIMER_MODE_ABS);
- leap_timer.function = ntp_leap_second;
}
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 15be32e19c6e..d66b21308f7c 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -184,18 +184,6 @@ static void timekeeping_update(bool clearntp)
}
-void timekeeping_leap_insert(int leapsecond)
-{
- unsigned long flags;
-
- write_seqlock_irqsave(&timekeeper.lock, flags);
- timekeeper.xtime.tv_sec += leapsecond;
- timekeeper.wall_to_monotonic.tv_sec -= leapsecond;
- timekeeping_update(false);
- write_sequnlock_irqrestore(&timekeeper.lock, flags);
-
-}
-
/**
* timekeeping_forward_now - update clock to the current time
*
@@ -448,9 +436,12 @@ EXPORT_SYMBOL(timekeeping_inject_offset);
static int change_clocksource(void *data)
{
struct clocksource *new, *old;
+ unsigned long flags;
new = (struct clocksource *) data;
+ write_seqlock_irqsave(&timekeeper.lock, flags);
+
timekeeping_forward_now();
if (!new->enable || new->enable(new) == 0) {
old = timekeeper.clock;
@@ -458,6 +449,10 @@ static int change_clocksource(void *data)
if (old->disable)
old->disable(old);
}
+ timekeeping_update(true);
+
+ write_sequnlock_irqrestore(&timekeeper.lock, flags);
+
return 0;
}
@@ -827,7 +822,7 @@ static void timekeeping_adjust(s64 offset)
int adj;
/*
- * The point of this is to check if the error is greater then half
+ * The point of this is to check if the error is greater than half
* an interval.
*
* First we shift it down from NTP_SHIFT to clocksource->shifted nsecs.
@@ -835,7 +830,7 @@ static void timekeeping_adjust(s64 offset)
* Note we subtract one in the shift, so that error is really error*2.
* This "saves" dividing(shifting) interval twice, but keeps the
* (error > interval) comparison as still measuring if error is
- * larger then half an interval.
+ * larger than half an interval.
*
* Note: It does not "save" on aggravation when reading the code.
*/
@@ -843,7 +838,7 @@ static void timekeeping_adjust(s64 offset)
if (error > interval) {
/*
* We now divide error by 4(via shift), which checks if
- * the error is greater then twice the interval.
+ * the error is greater than twice the interval.
* If it is greater, we need a bigadjust, if its smaller,
* we can adjust by 1.
*/
@@ -874,13 +869,15 @@ static void timekeeping_adjust(s64 offset)
} else /* No adjustment needed */
return;
- WARN_ONCE(timekeeper.clock->maxadj &&
- (timekeeper.mult + adj > timekeeper.clock->mult +
- timekeeper.clock->maxadj),
- "Adjusting %s more then 11%% (%ld vs %ld)\n",
+ if (unlikely(timekeeper.clock->maxadj &&
+ (timekeeper.mult + adj >
+ timekeeper.clock->mult + timekeeper.clock->maxadj))) {
+ printk_once(KERN_WARNING
+ "Adjusting %s more than 11%% (%ld vs %ld)\n",
timekeeper.clock->name, (long)timekeeper.mult + adj,
(long)timekeeper.clock->mult +
timekeeper.clock->maxadj);
+ }
/*
* So the following can be confusing.
*
@@ -952,7 +949,7 @@ static cycle_t logarithmic_accumulation(cycle_t offset, int shift)
u64 nsecps = (u64)NSEC_PER_SEC << timekeeper.shift;
u64 raw_nsecs;
- /* If the offset is smaller then a shifted interval, do nothing */
+ /* If the offset is smaller than a shifted interval, do nothing */
if (offset < timekeeper.cycle_interval<<shift)
return offset;
@@ -962,9 +959,11 @@ static cycle_t logarithmic_accumulation(cycle_t offset, int shift)
timekeeper.xtime_nsec += timekeeper.xtime_interval << shift;
while (timekeeper.xtime_nsec >= nsecps) {
+ int leap;
timekeeper.xtime_nsec -= nsecps;
timekeeper.xtime.tv_sec++;
- second_overflow();
+ leap = second_overflow(timekeeper.xtime.tv_sec);
+ timekeeper.xtime.tv_sec += leap;
}
/* Accumulate raw time */
@@ -1018,13 +1017,13 @@ static void update_wall_time(void)
* With NO_HZ we may have to accumulate many cycle_intervals
* (think "ticks") worth of time at once. To do this efficiently,
* we calculate the largest doubling multiple of cycle_intervals
- * that is smaller then the offset. We then accumulate that
+ * that is smaller than the offset. We then accumulate that
* chunk in one go, and then try to consume the next smaller
* doubled multiple.
*/
shift = ilog2(offset) - ilog2(timekeeper.cycle_interval);
shift = max(0, shift);
- /* Bound shift to one less then what overflows tick_length */
+ /* Bound shift to one less than what overflows tick_length */
maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1;
shift = min(shift, maxshift);
while (offset >= timekeeper.cycle_interval) {
@@ -1072,12 +1071,14 @@ static void update_wall_time(void)
/*
* Finally, make sure that after the rounding
- * xtime.tv_nsec isn't larger then NSEC_PER_SEC
+ * xtime.tv_nsec isn't larger than NSEC_PER_SEC
*/
if (unlikely(timekeeper.xtime.tv_nsec >= NSEC_PER_SEC)) {
+ int leap;
timekeeper.xtime.tv_nsec -= NSEC_PER_SEC;
timekeeper.xtime.tv_sec++;
- second_overflow();
+ leap = second_overflow(timekeeper.xtime.tv_sec);
+ timekeeper.xtime.tv_sec += leap;
}
timekeeping_update(false);