X-Git-Url: http://pilppa.org/gitweb/?a=blobdiff_plain;f=kernel%2Ftimer.c;h=5a8960253063d00495366a48d92e06e5eb4133fa;hb=b915543b46a2aa599fdd2169e51bcfd88812a12b;hp=67eaf0f54096f87162a96daad0b50df11fe5653f;hpb=edc4ff7c08e9885c40e60c4fb39fa42cc91a0602;p=linux-2.6-omap-h63xx.git diff --git a/kernel/timer.c b/kernel/timer.c index 67eaf0f5409..5a896025306 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -146,7 +146,7 @@ static void internal_add_timer(tvec_base_t *base, struct timer_list *timer) void fastcall init_timer(struct timer_list *timer) { timer->entry.next = NULL; - timer->base = per_cpu(tvec_bases, raw_smp_processor_id()); + timer->base = __raw_get_cpu_var(tvec_bases); } EXPORT_SYMBOL(init_timer); @@ -383,23 +383,19 @@ EXPORT_SYMBOL(del_timer_sync); static int cascade(tvec_base_t *base, tvec_t *tv, int index) { /* cascade all the timers from tv up one level */ - struct list_head *head, *curr; + struct timer_list *timer, *tmp; + struct list_head tv_list; + + list_replace_init(tv->vec + index, &tv_list); - head = tv->vec + index; - curr = head->next; /* - * We are removing _all_ timers from the list, so we don't have to - * detach them individually, just clear the list afterwards. + * We are removing _all_ timers from the list, so we + * don't have to detach them individually. */ - while (curr != head) { - struct timer_list *tmp; - - tmp = list_entry(curr, struct timer_list, entry); - BUG_ON(tmp->base != base); - curr = curr->next; - internal_add_timer(base, tmp); + list_for_each_entry_safe(timer, tmp, &tv_list, entry) { + BUG_ON(timer->base != base); + internal_add_timer(base, timer); } - INIT_LIST_HEAD(head); return index; } @@ -419,10 +415,10 @@ static inline void __run_timers(tvec_base_t *base) spin_lock_irq(&base->lock); while (time_after_eq(jiffies, base->timer_jiffies)) { - struct list_head work_list = LIST_HEAD_INIT(work_list); + struct list_head work_list; struct list_head *head = &work_list; int index = base->timer_jiffies & TVR_MASK; - + /* * Cascade timers: */ @@ -431,8 +427,8 @@ static inline void __run_timers(tvec_base_t *base) (!cascade(base, &base->tv3, INDEX(1))) && !cascade(base, &base->tv4, INDEX(2))) cascade(base, &base->tv5, INDEX(3)); - ++base->timer_jiffies; - list_splice_init(base->tv1.vec + index, &work_list); + ++base->timer_jiffies; + list_replace_init(base->tv1.vec + index, &work_list); while (!list_empty(head)) { void (*fn)(unsigned long); unsigned long data; @@ -541,6 +537,22 @@ found: } spin_unlock(&base->lock); + /* + * It can happen that other CPUs service timer IRQs and increment + * jiffies, but we have not yet got a local timer tick to process + * the timer wheels. In that case, the expiry time can be before + * jiffies, but since the high-resolution timer here is relative to + * jiffies, the default expression when high-resolution timers are + * not active, + * + * time_before(MAX_JIFFY_OFFSET + jiffies, expires) + * + * would falsely evaluate to true. If that is the case, just + * return jiffies so that we can immediately fire the local timer + */ + if (time_before(expires, jiffies)) + return jiffies; + if (time_before(hr_expires, expires)) return hr_expires; @@ -585,7 +597,6 @@ 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) */ -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) */ @@ -735,27 +746,14 @@ static long adjtime_adjustment(void) } /* 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) { @@ -768,36 +766,378 @@ static void update_wall_time_one_tick(void) * 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; } -/* - * Using a loop looks inefficient, but "ticks" is - * usually just one (we shouldn't be losing ticks, - * we're doing this this way mainly for interrupt - * latency reasons, not because we think we'll - * have lots of lost timer ticks +/* XXX - all of this timekeeping code should be later moved to time.c */ +#include +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 void update_wall_time(unsigned long ticks) +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 { - ticks--; - update_wall_time_one_tick(); - if (xtime.tv_nsec >= 1000000000) { - xtime.tv_nsec -= 1000000000; + 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); + + 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 + */ +void __init timekeeping_init(void) +{ + unsigned long flags; + + write_seqlock_irqsave(&xtime_lock, flags); + clock = clocksource_get_next(); + clocksource_calculate_interval(clock, tick_nsec); + clock->cycle_last = clocksource_read(clock); + ntp_clear(); + write_sequnlock_irqrestore(&xtime_lock, flags); +} + + +/* + * 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 + * still managed by arch specific suspend/resume code. + */ +static int timekeeping_resume(struct sys_device *dev) +{ + unsigned long flags; + + write_seqlock_irqsave(&xtime_lock, flags); + /* restart the last cycle value */ + clock->cycle_last = clocksource_read(clock); + write_sequnlock_irqrestore(&xtime_lock, flags); + return 0; +} + +/* sysfs resume/suspend bits for timekeeping */ +static struct sysdev_class timekeeping_sysclass = { + .resume = timekeeping_resume, + 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 another tick, + * to compensate for late or lost adjustments. + */ +static __always_inline int clocksource_bigadjust(int sign, s64 error, s64 *interval, s64 *offset) +{ + int adj; + + /* + * As soon as the machine is synchronized to the external time + * source this should be the common case. + */ + error >>= 2; + if (likely(sign > 0 ? error <= *interval : error >= *interval)) + return sign; + + /* + * An extra look ahead dampens the effect of the current error, + * which can grow quite large with continously late updates, as + * it would dominate the adjustment value and can lead to + * oscillation. + */ + error += current_tick_length() >> (TICK_LENGTH_SHIFT - clock->shift + 1); + error -= clock->xtime_interval >> 1; + + adj = 0; + while (1) { + error >>= 1; + if (sign > 0 ? error <= *interval : error >= *interval) + break; + adj++; + } + + /* + * Add the current adjustments to the error and take the offset + * into account, the latter can cause the error to be hardly + * reduced at the next tick. Check the error again if there's + * room for another adjustment, thus further reducing the error + * which otherwise had to be corrected at the next update. + */ + error = (error << 1) - *interval + *offset; + if (sign > 0 ? error > *interval : error < *interval) + adj++; + + *interval <<= adj; + *offset <<= adj; + return sign << 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) { + adj = clocksource_bigadjust(1, error, &interval, &offset); + } else if (error < -interval) { + interval = -interval; + offset = -offset; + adj = clocksource_bigadjust(-1, 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; + + clock->xtime_nsec += (s64)xtime.tv_nsec << clock->shift; + +#ifdef CONFIG_GENERIC_TIME + offset = (clocksource_read(clock) - clock->cycle_last) & clock->mask; +#else + offset = clock->cycle_interval; +#endif + + /* 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(); } - } while (ticks); + + /* 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 = 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); + } } /* @@ -903,10 +1243,8 @@ static inline void update_times(void) unsigned long ticks; ticks = jiffies - wall_jiffies; - if (ticks) { - wall_jiffies += ticks; - update_wall_time(ticks); - } + wall_jiffies += ticks; + update_wall_time(); calc_load(ticks); } @@ -1314,7 +1652,7 @@ static void __devinit migrate_timers(int cpu) } #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; @@ -1334,7 +1672,7 @@ static int timer_cpu_notify(struct notifier_block *self, return NOTIFY_OK; } -static struct notifier_block timers_nb = { +static struct notifier_block __devinitdata timers_nb = { .notifier_call = timer_cpu_notify, };