summaryrefslogtreecommitdiffstats
path: root/kernel/timer.c
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/timer.c')
-rw-r--r--kernel/timer.c283
1 files changed, 33 insertions, 250 deletions
diff --git a/kernel/timer.c b/kernel/timer.c
index 1d7dd6267c2..c1c7fbcffec 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -41,12 +41,6 @@
#include <asm/timex.h>
#include <asm/io.h>
-#ifdef CONFIG_TIME_INTERPOLATION
-static void time_interpolator_update(long delta_nsec);
-#else
-#define time_interpolator_update(x)
-#endif
-
u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES;
EXPORT_SYMBOL(jiffies_64);
@@ -136,7 +130,7 @@ static void internal_add_timer(tvec_base_t *base, struct timer_list *timer)
list_add_tail(&timer->entry, vec);
}
-/***
+/**
* init_timer - initialize a timer.
* @timer: the timer to be initialized
*
@@ -175,6 +169,7 @@ static inline void detach_timer(struct timer_list *timer,
*/
static tvec_base_t *lock_timer_base(struct timer_list *timer,
unsigned long *flags)
+ __acquires(timer->base->lock)
{
tvec_base_t *base;
@@ -235,7 +230,7 @@ int __mod_timer(struct timer_list *timer, unsigned long expires)
EXPORT_SYMBOL(__mod_timer);
-/***
+/**
* add_timer_on - start a timer on a particular CPU
* @timer: the timer to be added
* @cpu: the CPU to start it on
@@ -255,9 +250,10 @@ void add_timer_on(struct timer_list *timer, int cpu)
}
-/***
+/**
* mod_timer - modify a timer's timeout
* @timer: the timer to be modified
+ * @expires: new timeout in jiffies
*
* mod_timer is a more efficient way to update the expire field of an
* active timer (if the timer is inactive it will be activated)
@@ -291,7 +287,7 @@ int mod_timer(struct timer_list *timer, unsigned long expires)
EXPORT_SYMBOL(mod_timer);
-/***
+/**
* del_timer - deactive a timer.
* @timer: the timer to be deactivated
*
@@ -323,7 +319,10 @@ int del_timer(struct timer_list *timer)
EXPORT_SYMBOL(del_timer);
#ifdef CONFIG_SMP
-/*
+/**
+ * try_to_del_timer_sync - Try to deactivate a timer
+ * @timer: timer do del
+ *
* This function tries to deactivate a timer. Upon successful (ret >= 0)
* exit the timer is not queued and the handler is not running on any CPU.
*
@@ -351,7 +350,7 @@ out:
return ret;
}
-/***
+/**
* del_timer_sync - deactivate a timer and wait for the handler to finish.
* @timer: the timer to be deactivated
*
@@ -401,15 +400,15 @@ static int cascade(tvec_base_t *base, tvec_t *tv, int index)
return index;
}
-/***
+#define INDEX(N) ((base->timer_jiffies >> (TVR_BITS + (N) * TVN_BITS)) & TVN_MASK)
+
+/**
* __run_timers - run all expired timers (if any) on this CPU.
* @base: the timer vector to be processed.
*
* This function cascades all vectors and executes all expired timer
* vectors.
*/
-#define INDEX(N) ((base->timer_jiffies >> (TVR_BITS + (N) * TVN_BITS)) & TVN_MASK)
-
static inline void __run_timers(tvec_base_t *base)
{
struct timer_list *timer;
@@ -563,12 +562,6 @@ found:
/******************************************************************/
-/*
- * Timekeeping variables
- */
-unsigned long tick_usec = TICK_USEC; /* USER_HZ period (usec) */
-unsigned long tick_nsec = TICK_NSEC; /* ACTHZ period (nsec) */
-
/*
* The current time
* wall_to_monotonic is what we need to add to xtime (or xtime corrected
@@ -582,209 +575,6 @@ struct timespec wall_to_monotonic __attribute__ ((aligned (16)));
EXPORT_SYMBOL(xtime);
-/* Don't completely fail for HZ > 500. */
-int tickadj = 500/HZ ? : 1; /* microsecs */
-
-
-/*
- * phase-lock loop variables
- */
-/* TIME_ERROR prevents overwriting the CMOS clock */
-int time_state = TIME_OK; /* clock synchronization status */
-int time_status = STA_UNSYNC; /* clock status bits */
-long time_offset; /* time adjustment (us) */
-long time_constant = 2; /* pll time constant */
-long time_tolerance = MAXFREQ; /* frequency tolerance (ppm) */
-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) */
-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) */
-long time_reftime; /* time at last adjustment (s) */
-long time_adjust;
-long time_next_adjust;
-
-/*
- * 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.
- *
- */
-static void second_overflow(void)
-{
- long ltemp;
-
- /* Bump the maxerror field */
- time_maxerror += time_tolerance >> SHIFT_USEC;
- if (time_maxerror > NTP_PHASE_LIMIT) {
- time_maxerror = NTP_PHASE_LIMIT;
- time_status |= STA_UNSYNC;
- }
-
- /*
- * 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. The microtime()
- * routine or external clock driver will insure that reported time is
- * always monotonic. The ugly divides should be replaced.
- */
- 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:
- if (xtime.tv_sec % 86400 == 0) {
- xtime.tv_sec--;
- wall_to_monotonic.tv_sec++;
- /*
- * The timer interpolator will make time change
- * gradually instead of an immediate jump by one second
- */
- time_interpolator_update(-NSEC_PER_SEC);
- time_state = TIME_OOP;
- clock_was_set();
- printk(KERN_NOTICE "Clock: inserting leap second "
- "23:59:60 UTC\n");
- }
- break;
- case TIME_DEL:
- if ((xtime.tv_sec + 1) % 86400 == 0) {
- xtime.tv_sec++;
- wall_to_monotonic.tv_sec--;
- /*
- * Use of time interpolator for a gradual change of
- * time
- */
- time_interpolator_update(NSEC_PER_SEC);
- time_state = TIME_WAIT;
- clock_was_set();
- printk(KERN_NOTICE "Clock: deleting leap second "
- "23:59:59 UTC\n");
- }
- break;
- case TIME_OOP:
- time_state = TIME_WAIT;
- break;
- case TIME_WAIT:
- if (!(time_status & (STA_INS | STA_DEL)))
- time_state = TIME_OK;
- }
-
- /*
- * Compute the phase adjustment for the next second. In PLL mode, the
- * offset is reduced by a fixed factor times the time constant. In FLL
- * mode the offset is used directly. In either mode, the maximum phase
- * adjustment for each second is clamped so as to spread the adjustment
- * over not more than the number of seconds between updates.
- */
- ltemp = time_offset;
- if (!(time_status & STA_FLL))
- ltemp = shift_right(ltemp, SHIFT_KG + time_constant);
- ltemp = min(ltemp, (MAXPHASE / MINSEC) << SHIFT_UPDATE);
- ltemp = max(ltemp, -(MAXPHASE / MINSEC) << SHIFT_UPDATE);
- time_offset -= ltemp;
- time_adj = ltemp << (SHIFT_SCALE - SHIFT_HZ - SHIFT_UPDATE);
-
- /*
- * Compute the frequency estimate and additional phase adjustment due
- * to frequency error for the next second.
- */
- ltemp = time_freq;
- time_adj += shift_right(ltemp,(SHIFT_USEC + SHIFT_HZ - SHIFT_SCALE));
-
-#if HZ == 100
- /*
- * Compensate for (HZ==100) != (1 << SHIFT_HZ). Add 25% and 3.125% to
- * get 128.125; => only 0.125% error (p. 14)
- */
- time_adj += shift_right(time_adj, 2) + shift_right(time_adj, 5);
-#endif
-#if HZ == 250
- /*
- * Compensate for (HZ==250) != (1 << SHIFT_HZ). Add 1.5625% and
- * 0.78125% to get 255.85938; => only 0.05% error (p. 14)
- */
- time_adj += shift_right(time_adj, 6) + shift_right(time_adj, 7);
-#endif
-#if HZ == 1000
- /*
- * Compensate for (HZ==1000) != (1 << SHIFT_HZ). Add 1.5625% and
- * 0.78125% to get 1023.4375; => only 0.05% error (p. 14)
- */
- time_adj += shift_right(time_adj, 6) + shift_right(time_adj, 7);
-#endif
-}
-
-/*
- * Returns how many microseconds we need to add to xtime this tick
- * in doing an adjustment requested with adjtime.
- */
-static long adjtime_adjustment(void)
-{
- long time_adjust_step;
-
- time_adjust_step = time_adjust;
- if (time_adjust_step) {
- /*
- * We are doing an adjtime thing. Prepare time_adjust_step to
- * be within bounds. Note that a positive time_adjust means we
- * want the clock to run faster.
- *
- * Limit the amount of the step to be in the range
- * -tickadj .. +tickadj
- */
- time_adjust_step = min(time_adjust_step, (long)tickadj);
- time_adjust_step = max(time_adjust_step, (long)-tickadj);
- }
- return time_adjust_step;
-}
-
-/* in the NTP reference this is called "hardclock()" */
-static void update_ntp_one_tick(void)
-{
- 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;
-
- /* Changes by adjtime() do not take effect till next tick. */
- if (time_next_adjust != 0) {
- time_adjust = time_next_adjust;
- 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 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;
- 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>
@@ -961,21 +751,24 @@ void __init timekeeping_init(void)
unsigned long flags;
write_seqlock_irqsave(&xtime_lock, flags);
+
+ ntp_clear();
+
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
*
* This is for the generic clocksource timekeeping.
- * xtime/wall_to_monotonic/jiffies/wall_jiffies/etc are
+ * xtime/wall_to_monotonic/jiffies/etc are
* still managed by arch specific suspend/resume code.
*/
static int timekeeping_resume(struct sys_device *dev)
@@ -1106,7 +899,7 @@ static void clocksource_adjust(struct clocksource *clock, s64 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.
@@ -1144,8 +937,6 @@ static void update_wall_time(void)
/* 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();
@@ -1217,19 +1008,14 @@ static inline void calc_load(unsigned long ticks)
unsigned long active_tasks; /* fixed-point */
static int count = LOAD_FREQ;
- count -= ticks;
- if (count < 0) {
- count += LOAD_FREQ;
- active_tasks = count_active_tasks();
+ active_tasks = count_active_tasks();
+ for (count -= ticks; count < 0; count += LOAD_FREQ) {
CALC_LOAD(avenrun[0], EXP_1, active_tasks);
CALC_LOAD(avenrun[1], EXP_5, active_tasks);
CALC_LOAD(avenrun[2], EXP_15, active_tasks);
}
}
-/* jiffies at the most recent update of wall time */
-unsigned long wall_jiffies = INITIAL_JIFFIES;
-
/*
* This read-write spinlock protects us from races in SMP while
* playing with xtime and avenrun.
@@ -1265,12 +1051,8 @@ void run_local_timers(void)
* Called by the timer interrupt. xtime_lock must already be taken
* by the timer IRQ!
*/
-static inline void update_times(void)
+static inline void update_times(unsigned long ticks)
{
- unsigned long ticks;
-
- ticks = jiffies - wall_jiffies;
- wall_jiffies += ticks;
update_wall_time();
calc_load(ticks);
}
@@ -1281,12 +1063,10 @@ static inline void update_times(void)
* jiffies is defined in the linker script...
*/
-void do_timer(struct pt_regs *regs)
+void do_timer(unsigned long ticks)
{
- jiffies_64++;
- /* prevent loading jiffies before storing new jiffies_64 value. */
- barrier();
- update_times();
+ jiffies_64 += ticks;
+ update_times(ticks);
}
#ifdef __ARCH_WANT_SYS_ALARM
@@ -1470,8 +1250,9 @@ asmlinkage long sys_gettid(void)
return current->pid;
}
-/*
+/**
* sys_sysinfo - fill in sysinfo struct
+ * @info: pointer to buffer to fill
*/
asmlinkage long sys_sysinfo(struct sysinfo __user *info)
{
@@ -1688,8 +1469,10 @@ static struct notifier_block __cpuinitdata timers_nb = {
void __init init_timers(void)
{
- timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE,
+ int err = timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE,
(void *)(long)smp_processor_id());
+
+ BUG_ON(err == NOTIFY_BAD);
register_cpu_notifier(&timers_nb);
open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL);
}
@@ -1774,7 +1557,7 @@ unsigned long time_interpolator_get_offset(void)
#define INTERPOLATOR_ADJUST 65536
#define INTERPOLATOR_MAX_SKIP 10*INTERPOLATOR_ADJUST
-static void time_interpolator_update(long delta_nsec)
+void time_interpolator_update(long delta_nsec)
{
u64 counter;
unsigned long offset;
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-11-21 19:17:27 +0000