diff options
Diffstat (limited to 'kernel/timer.c')
| -rw-r--r-- | kernel/timer.c | 283 |
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; |