Move timekeeping code to timekeeping.c
Move the timekeeping code out of kernel/timer.c and into
kernel/time/timekeeping.c. I made no cleanups or other changes in transit.
[akpm@linux-foundation.org: build fix]
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/timer.c b/kernel/timer.c
index dbe966f..ba41af2 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -1,7 +1,7 @@
/*
* linux/kernel/timer.c
*
- * Kernel internal timers, kernel timekeeping, basic process system calls
+ * Kernel internal timers, basic process system calls
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
@@ -794,455 +794,6 @@
#endif
-/******************************************************************/
-
-/*
- * The current time
- * wall_to_monotonic is what we need to add to xtime (or xtime corrected
- * for sub jiffie times) to get to monotonic time. Monotonic is pegged
- * at zero at system boot time, so wall_to_monotonic will be negative,
- * however, we will ALWAYS keep the tv_nsec part positive so we can use
- * the usual normalization.
- */
-struct timespec xtime __attribute__ ((aligned (16)));
-struct timespec wall_to_monotonic __attribute__ ((aligned (16)));
-
-EXPORT_SYMBOL(xtime);
-
-
-/* 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 */
-
-#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();
-
- update_vsyscall(&xtime, clock);
-
- 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 void change_clocksource(void)
-{
- struct clocksource *new;
- cycle_t now;
- u64 nsec;
-
- new = clocksource_get_next();
-
- if (clock == new)
- return;
-
- now = clocksource_read(new);
- nsec = __get_nsec_offset();
- timespec_add_ns(&xtime, nsec);
-
- clock = new;
- clock->cycle_last = now;
-
- clock->error = 0;
- clock->xtime_nsec = 0;
- clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH);
-
- tick_clock_notify();
-
- printk(KERN_INFO "Time: %s clocksource has been installed.\n",
- clock->name);
-}
-#else
-static inline void change_clocksource(void) { }
-#endif
-
-/**
- * timekeeping_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->flags & CLOCK_SOURCE_VALID_FOR_HRES;
-
- } while (read_seqretry(&xtime_lock, seq));
-
- return ret;
-}
-
-/**
- * read_persistent_clock - Return time in seconds from the persistent clock.
- *
- * Weak dummy function for arches that do not yet support it.
- * Returns seconds from epoch using the battery backed persistent clock.
- * Returns zero if unsupported.
- *
- * XXX - Do be sure to remove it once all arches implement it.
- */
-unsigned long __attribute__((weak)) read_persistent_clock(void)
-{
- return 0;
-}
-
-/*
- * timekeeping_init - Initializes the clocksource and common timekeeping values
- */
-void __init timekeeping_init(void)
-{
- unsigned long flags;
- unsigned long sec = read_persistent_clock();
-
- write_seqlock_irqsave(&xtime_lock, flags);
-
- ntp_clear();
-
- clock = clocksource_get_next();
- clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH);
- clock->cycle_last = clocksource_read(clock);
-
- xtime.tv_sec = sec;
- xtime.tv_nsec = 0;
- set_normalized_timespec(&wall_to_monotonic,
- -xtime.tv_sec, -xtime.tv_nsec);
-
- write_sequnlock_irqrestore(&xtime_lock, flags);
-}
-
-/* flag for if timekeeping is suspended */
-static int timekeeping_suspended;
-/* time in seconds when suspend began */
-static unsigned long timekeeping_suspend_time;
-
-/**
- * timekeeping_resume - Resumes the generic timekeeping subsystem.
- * @dev: unused
- *
- * This is for the generic clocksource timekeeping.
- * xtime/wall_to_monotonic/jiffies/etc are
- * still managed by arch specific suspend/resume code.
- */
-static int timekeeping_resume(struct sys_device *dev)
-{
- unsigned long flags;
- unsigned long now = read_persistent_clock();
-
- write_seqlock_irqsave(&xtime_lock, flags);
-
- if (now && (now > timekeeping_suspend_time)) {
- unsigned long sleep_length = now - timekeeping_suspend_time;
-
- xtime.tv_sec += sleep_length;
- wall_to_monotonic.tv_sec -= sleep_length;
- }
- /* re-base the last cycle value */
- clock->cycle_last = clocksource_read(clock);
- clock->error = 0;
- timekeeping_suspended = 0;
- write_sequnlock_irqrestore(&xtime_lock, flags);
-
- touch_softlockup_watchdog();
-
- clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL);
-
- /* Resume hrtimers */
- hres_timers_resume();
-
- 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;
- timekeeping_suspend_time = read_persistent_clock();
- write_sequnlock_irqrestore(&xtime_lock, flags);
-
- clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL);
-
- return 0;
-}
-
-/* sysfs resume/suspend bits for timekeeping */
-static struct sysdev_class timekeeping_sysclass = {
- .resume = timekeeping_resume,
- .suspend = timekeeping_suspend,
- set_kset_name("timekeeping"),
-};
-
-static struct sys_device device_timer = {
- .id = 0,
- .cls = &timekeeping_sysclass,
-};
-
-static int __init timekeeping_init_device(void)
-{
- int error = sysdev_class_register(&timekeeping_sysclass);
- if (!error)
- error = sysdev_register(&device_timer);
- return error;
-}
-
-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
- *
- * Called from the timer interrupt, must hold a write on xtime_lock.
- */
-static void update_wall_time(void)
-{
- cycle_t offset;
-
- /* Make sure we're fully resumed: */
- if (unlikely(timekeeping_suspended))
- return;
-
-#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->cycle_interval) {
- /* accumulate one interval */
- clock->xtime_nsec += clock->xtime_interval;
- clock->cycle_last += clock->cycle_interval;
- offset -= clock->cycle_interval;
-
- 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);
-
- /* 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 */
- change_clocksource();
- update_vsyscall(&xtime, clock);
-}
-
/*
* Called from the timer interrupt handler to charge one tick to the current
* process. user_tick is 1 if the tick is user time, 0 for system.
@@ -1306,14 +857,6 @@
}
/*
- * This read-write spinlock protects us from races in SMP while
- * playing with xtime and avenrun.
- */
-__attribute__((weak)) __cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock);
-
-EXPORT_SYMBOL(xtime_lock);
-
-/*
* This function runs timers and the timer-tq in bottom half context.
*/
static void run_timer_softirq(struct softirq_action *h)
