int ret = try_to_del_timer_sync(timer);
if (ret >= 0)
return ret;
+ cpu_relax();
}
}
long time_precision = 1; /* clock precision (us) */
long time_maxerror = NTP_PHASE_LIMIT; /* maximum error (us) */
long time_esterror = NTP_PHASE_LIMIT; /* estimated error (us) */
-static long time_phase; /* phase offset (scaled us) */
long time_freq = (((NSEC_PER_SEC + HZ/2) % HZ - HZ/2) << SHIFT_USEC) / NSEC_PER_USEC;
/* frequency offset (scaled ppm)*/
static long time_adj; /* tick adjust (scaled 1 / HZ) */
}
/* in the NTP reference this is called "hardclock()" */
-static void update_wall_time_one_tick(void)
+static void update_ntp_one_tick(void)
{
- long time_adjust_step, delta_nsec;
+ long time_adjust_step;
time_adjust_step = adjtime_adjustment();
if (time_adjust_step)
/* Reduce by this step the amount of time left */
time_adjust -= time_adjust_step;
- delta_nsec = tick_nsec + time_adjust_step * 1000;
- /*
- * Advance the phase, once it gets to one microsecond, then
- * advance the tick more.
- */
- time_phase += time_adj;
- if ((time_phase >= FINENSEC) || (time_phase <= -FINENSEC)) {
- long ltemp = shift_right(time_phase, (SHIFT_SCALE - 10));
- time_phase -= ltemp << (SHIFT_SCALE - 10);
- delta_nsec += ltemp;
- }
- xtime.tv_nsec += delta_nsec;
- time_interpolator_update(delta_nsec);
/* Changes by adjtime() do not take effect till next tick. */
if (time_next_adjust != 0) {
* Return how long ticks are at the moment, that is, how much time
* update_wall_time_one_tick will add to xtime next time we call it
* (assuming no calls to do_adjtimex in the meantime).
- * The return value is in fixed-point nanoseconds with SHIFT_SCALE-10
- * bits to the right of the binary point.
+ * The return value is in fixed-point nanoseconds shifted by the
+ * specified number of bits to the right of the binary point.
* This function has no side-effects.
*/
u64 current_tick_length(void)
{
long delta_nsec;
+ u64 ret;
+ /* calculate the finest interval NTP will allow.
+ * ie: nanosecond value shifted by (SHIFT_SCALE - 10)
+ */
delta_nsec = tick_nsec + adjtime_adjustment() * 1000;
- return ((u64) delta_nsec << (SHIFT_SCALE - 10)) + time_adj;
+ ret = (u64)delta_nsec << TICK_LENGTH_SHIFT;
+ ret += (s64)time_adj << (TICK_LENGTH_SHIFT - (SHIFT_SCALE - 10));
+
+ return ret;
}
/* XXX - all of this timekeeping code should be later moved to time.c */
#include <linux/clocksource.h>
static struct clocksource *clock; /* pointer to current clocksource */
-static cycle_t last_clock_cycle; /* cycle value at last update_wall_time */
+
+#ifdef CONFIG_GENERIC_TIME
+/**
+ * __get_nsec_offset - Returns nanoseconds since last call to periodic_hook
+ *
+ * private function, must hold xtime_lock lock when being
+ * called. Returns the number of nanoseconds since the
+ * last call to update_wall_time() (adjusted by NTP scaling)
+ */
+static inline s64 __get_nsec_offset(void)
+{
+ cycle_t cycle_now, cycle_delta;
+ s64 ns_offset;
+
+ /* read clocksource: */
+ cycle_now = clocksource_read(clock);
+
+ /* calculate the delta since the last update_wall_time: */
+ cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
+
+ /* convert to nanoseconds: */
+ ns_offset = cyc2ns(clock, cycle_delta);
+
+ return ns_offset;
+}
+
+/**
+ * __get_realtime_clock_ts - Returns the time of day in a timespec
+ * @ts: pointer to the timespec to be set
+ *
+ * Returns the time of day in a timespec. Used by
+ * do_gettimeofday() and get_realtime_clock_ts().
+ */
+static inline void __get_realtime_clock_ts(struct timespec *ts)
+{
+ unsigned long seq;
+ s64 nsecs;
+
+ do {
+ seq = read_seqbegin(&xtime_lock);
+
+ *ts = xtime;
+ nsecs = __get_nsec_offset();
+
+ } while (read_seqretry(&xtime_lock, seq));
+
+ timespec_add_ns(ts, nsecs);
+}
+
+/**
+ * getnstimeofday - Returns the time of day in a timespec
+ * @ts: pointer to the timespec to be set
+ *
+ * Returns the time of day in a timespec.
+ */
+void getnstimeofday(struct timespec *ts)
+{
+ __get_realtime_clock_ts(ts);
+}
+
+EXPORT_SYMBOL(getnstimeofday);
+
+/**
+ * do_gettimeofday - Returns the time of day in a timeval
+ * @tv: pointer to the timeval to be set
+ *
+ * NOTE: Users should be converted to using get_realtime_clock_ts()
+ */
+void do_gettimeofday(struct timeval *tv)
+{
+ struct timespec now;
+
+ __get_realtime_clock_ts(&now);
+ tv->tv_sec = now.tv_sec;
+ tv->tv_usec = now.tv_nsec/1000;
+}
+
+EXPORT_SYMBOL(do_gettimeofday);
+/**
+ * do_settimeofday - Sets the time of day
+ * @tv: pointer to the timespec variable containing the new time
+ *
+ * Sets the time of day to the new time and update NTP and notify hrtimers
+ */
+int do_settimeofday(struct timespec *tv)
+{
+ unsigned long flags;
+ time_t wtm_sec, sec = tv->tv_sec;
+ long wtm_nsec, nsec = tv->tv_nsec;
+
+ if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
+ return -EINVAL;
+
+ write_seqlock_irqsave(&xtime_lock, flags);
+
+ nsec -= __get_nsec_offset();
+
+ wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
+ wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
+
+ set_normalized_timespec(&xtime, sec, nsec);
+ set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
+
+ clock->error = 0;
+ ntp_clear();
+
+ write_sequnlock_irqrestore(&xtime_lock, flags);
+
+ /* signal hrtimers about time change */
+ clock_was_set();
+
+ return 0;
+}
+
+EXPORT_SYMBOL(do_settimeofday);
+
+/**
+ * change_clocksource - Swaps clocksources if a new one is available
+ *
+ * Accumulates current time interval and initializes new clocksource
+ */
+static int change_clocksource(void)
+{
+ struct clocksource *new;
+ cycle_t now;
+ u64 nsec;
+ new = clocksource_get_next();
+ if (clock != new) {
+ now = clocksource_read(new);
+ nsec = __get_nsec_offset();
+ timespec_add_ns(&xtime, nsec);
+
+ clock = new;
+ clock->cycle_last = now;
+ printk(KERN_INFO "Time: %s clocksource has been installed.\n",
+ clock->name);
+ return 1;
+ } else if (clock->update_callback) {
+ return clock->update_callback();
+ }
+ return 0;
+}
+#else
+#define change_clocksource() (0)
+#endif
+
+/**
+ * timeofday_is_continuous - check to see if timekeeping is free running
+ */
+int timekeeping_is_continuous(void)
+{
+ unsigned long seq;
+ int ret;
+
+ do {
+ seq = read_seqbegin(&xtime_lock);
+
+ ret = clock->is_continuous;
+
+ } while (read_seqretry(&xtime_lock, seq));
+
+ return ret;
+}
+
/*
* timekeeping_init - Initializes the clocksource and common timekeeping values
*/
unsigned long flags;
write_seqlock_irqsave(&xtime_lock, flags);
- clock = get_next_clocksource();
- calculate_clocksource_interval(clock, tick_nsec);
- last_clock_cycle = read_clocksource(clock);
+ clock = clocksource_get_next();
+ clocksource_calculate_interval(clock, tick_nsec);
+ clock->cycle_last = clocksource_read(clock);
ntp_clear();
write_sequnlock_irqrestore(&xtime_lock, flags);
}
+static int timekeeping_suspended;
/*
* timekeeping_resume - Resumes the generic timekeeping subsystem.
* @dev: unused
write_seqlock_irqsave(&xtime_lock, flags);
/* restart the last cycle value */
- last_clock_cycle = read_clocksource(clock);
+ clock->cycle_last = clocksource_read(clock);
+ clock->error = 0;
+ timekeeping_suspended = 0;
+ write_sequnlock_irqrestore(&xtime_lock, flags);
+ return 0;
+}
+
+static int timekeeping_suspend(struct sys_device *dev, pm_message_t state)
+{
+ unsigned long flags;
+
+ write_seqlock_irqsave(&xtime_lock, flags);
+ timekeeping_suspended = 1;
write_sequnlock_irqrestore(&xtime_lock, flags);
return 0;
}
/* sysfs resume/suspend bits for timekeeping */
static struct sysdev_class timekeeping_sysclass = {
.resume = timekeeping_resume,
+ .suspend = timekeeping_suspend,
set_kset_name("timekeeping"),
};
device_initcall(timekeeping_init_device);
+/*
+ * If the error is already larger, we look ahead even further
+ * to compensate for late or lost adjustments.
+ */
+static __always_inline int clocksource_bigadjust(s64 error, s64 *interval, s64 *offset)
+{
+ s64 tick_error, i;
+ u32 look_ahead, adj;
+ s32 error2, mult;
+
+ /*
+ * Use the current error value to determine how much to look ahead.
+ * The larger the error the slower we adjust for it to avoid problems
+ * with losing too many ticks, otherwise we would overadjust and
+ * produce an even larger error. The smaller the adjustment the
+ * faster we try to adjust for it, as lost ticks can do less harm
+ * here. This is tuned so that an error of about 1 msec is adusted
+ * within about 1 sec (or 2^20 nsec in 2^SHIFT_HZ ticks).
+ */
+ error2 = clock->error >> (TICK_LENGTH_SHIFT + 22 - 2 * SHIFT_HZ);
+ error2 = abs(error2);
+ for (look_ahead = 0; error2 > 0; look_ahead++)
+ error2 >>= 2;
+
+ /*
+ * Now calculate the error in (1 << look_ahead) ticks, but first
+ * remove the single look ahead already included in the error.
+ */
+ tick_error = current_tick_length() >> (TICK_LENGTH_SHIFT - clock->shift + 1);
+ tick_error -= clock->xtime_interval >> 1;
+ error = ((error - tick_error) >> look_ahead) + tick_error;
+
+ /* Finally calculate the adjustment shift value. */
+ i = *interval;
+ mult = 1;
+ if (error < 0) {
+ error = -error;
+ *interval = -*interval;
+ *offset = -*offset;
+ mult = -1;
+ }
+ for (adj = 0; error > i; adj++)
+ error >>= 1;
+
+ *interval <<= adj;
+ *offset <<= adj;
+ return mult << adj;
+}
+
+/*
+ * Adjust the multiplier to reduce the error value,
+ * this is optimized for the most common adjustments of -1,0,1,
+ * for other values we can do a bit more work.
+ */
+static void clocksource_adjust(struct clocksource *clock, s64 offset)
+{
+ s64 error, interval = clock->cycle_interval;
+ int adj;
+
+ error = clock->error >> (TICK_LENGTH_SHIFT - clock->shift - 1);
+ if (error > interval) {
+ error >>= 2;
+ if (likely(error <= interval))
+ adj = 1;
+ else
+ adj = clocksource_bigadjust(error, &interval, &offset);
+ } else if (error < -interval) {
+ error >>= 2;
+ if (likely(error >= -interval)) {
+ adj = -1;
+ interval = -interval;
+ offset = -offset;
+ } else
+ adj = clocksource_bigadjust(error, &interval, &offset);
+ } else
+ return;
+
+ clock->mult += adj;
+ clock->xtime_interval += interval;
+ clock->xtime_nsec -= offset;
+ clock->error -= (interval - offset) << (TICK_LENGTH_SHIFT - clock->shift);
+}
+
/*
* update_wall_time - Uses the current clocksource to increment the wall time
*
*/
static void update_wall_time(void)
{
- cycle_t now, offset;
+ cycle_t offset;
+
+ /* Make sure we're fully resumed: */
+ if (unlikely(timekeeping_suspended))
+ return;
- now = read_clocksource(clock);
- offset = (now - last_clock_cycle)&clock->mask;
+#ifdef CONFIG_GENERIC_TIME
+ offset = (clocksource_read(clock) - clock->cycle_last) & clock->mask;
+#else
+ offset = clock->cycle_interval;
+#endif
+ clock->xtime_nsec += (s64)xtime.tv_nsec << clock->shift;
/* normally this loop will run just once, however in the
* case of lost or late ticks, it will accumulate correctly.
*/
- while (offset > clock->interval_cycles) {
+ while (offset >= clock->cycle_interval) {
/* accumulate one interval */
- last_clock_cycle += clock->interval_cycles;
- offset -= clock->interval_cycles;
+ clock->xtime_nsec += clock->xtime_interval;
+ clock->cycle_last += clock->cycle_interval;
+ offset -= clock->cycle_interval;
- update_wall_time_one_tick();
- if (xtime.tv_nsec >= 1000000000) {
- xtime.tv_nsec -= 1000000000;
+ if (clock->xtime_nsec >= (u64)NSEC_PER_SEC << clock->shift) {
+ clock->xtime_nsec -= (u64)NSEC_PER_SEC << clock->shift;
xtime.tv_sec++;
second_overflow();
}
+
+ /* interpolator bits */
+ time_interpolator_update(clock->xtime_interval
+ >> clock->shift);
+ /* increment the NTP state machine */
+ update_ntp_one_tick();
+
+ /* accumulate error between NTP and clock interval */
+ clock->error += current_tick_length();
+ clock->error -= clock->xtime_interval << (TICK_LENGTH_SHIFT - clock->shift);
+ }
+
+ /* correct the clock when NTP error is too big */
+ clocksource_adjust(clock, offset);
+
+ /* store full nanoseconds into xtime */
+ xtime.tv_nsec = (s64)clock->xtime_nsec >> clock->shift;
+ clock->xtime_nsec -= (s64)xtime.tv_nsec << clock->shift;
+
+ /* check to see if there is a new clocksource to use */
+ if (change_clocksource()) {
+ clock->error = 0;
+ clock->xtime_nsec = 0;
+ clocksource_calculate_interval(clock, tick_nsec);
}
}
* playing with xtime and avenrun.
*/
#ifndef ARCH_HAVE_XTIME_LOCK
-seqlock_t xtime_lock __cacheline_aligned_in_smp = SEQLOCK_UNLOCKED;
+__cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock);
EXPORT_SYMBOL(xtime_lock);
#endif
static void process_timeout(unsigned long __data)
{
- wake_up_process((task_t *)__data);
+ wake_up_process((struct task_struct *)__data);
}
/**
return 0;
}
+/*
+ * lockdep: we want to track each per-CPU base as a separate lock-class,
+ * but timer-bases are kmalloc()-ed, so we need to attach separate
+ * keys to them:
+ */
+static struct lock_class_key base_lock_keys[NR_CPUS];
+
static int __devinit init_timers_cpu(int cpu)
{
int j;
}
spin_lock_init(&base->lock);
+ lockdep_set_class(&base->lock, base_lock_keys + cpu);
+
for (j = 0; j < TVN_SIZE; j++) {
INIT_LIST_HEAD(base->tv5.vec + j);
INIT_LIST_HEAD(base->tv4.vec + j);
}
#endif /* CONFIG_HOTPLUG_CPU */
-static int timer_cpu_notify(struct notifier_block *self,
+static int __devinit timer_cpu_notify(struct notifier_block *self,
unsigned long action, void *hcpu)
{
long cpu = (long)hcpu;
return NOTIFY_OK;
}
-static struct notifier_block timers_nb = {
+static struct notifier_block __devinitdata timers_nb = {
.notifier_call = timer_cpu_notify,
};
projects / ~andy / linux / blobdiff