X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=kernel%2Ftimer.c;h=1bbbceea917e0ce33961c7560a22b2135c28178a;hb=9464c7cf61b9433057924c36e6e02f303a00e768;hp=ea6ec802d3e36ff5294ea1965fc9bdd17d4492df;hpb=41689045f6a3cbe0550e1d34e9cc20d2e8c432ba;p=linux-2.6.git diff --git a/kernel/timer.c b/kernel/timer.c index ea6ec802d..1bbbceea9 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -87,7 +87,7 @@ typedef struct tvec_t_base_s tvec_base_t; tvec_base_t boot_tvec_bases; EXPORT_SYMBOL(boot_tvec_bases); -static DEFINE_PER_CPU(tvec_base_t *, tvec_bases) = &boot_tvec_bases; +static DEFINE_PER_CPU(tvec_base_t *, tvec_bases) = { &boot_tvec_bases }; static inline void set_running_timer(tvec_base_t *base, struct timer_list *timer) @@ -149,7 +149,7 @@ 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 = __raw_get_cpu_var(tvec_bases); + timer->base = per_cpu(tvec_bases, raw_smp_processor_id()); } EXPORT_SYMBOL(init_timer); @@ -377,7 +377,6 @@ int del_timer_sync(struct timer_list *timer) int ret = try_to_del_timer_sync(timer); if (ret >= 0) return ret; - cpu_relax(); } } @@ -387,19 +386,23 @@ 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 timer_list *timer, *tmp; - struct list_head tv_list; - - list_replace_init(tv->vec + index, &tv_list); + struct list_head *head, *curr; + head = tv->vec + index; + curr = head->next; /* - * We are removing _all_ timers from the list, so we - * don't have to detach them individually. + * We are removing _all_ timers from the list, so we don't have to + * detach them individually, just clear the list afterwards. */ - list_for_each_entry_safe(timer, tmp, &tv_list, entry) { - BUG_ON(timer->base != base); - internal_add_timer(base, timer); + 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); } + INIT_LIST_HEAD(head); return index; } @@ -411,7 +414,7 @@ static int cascade(tvec_base_t *base, tvec_t *tv, int index) * This function cascades all vectors and executes all expired timer * vectors. */ -#define INDEX(N) ((base->timer_jiffies >> (TVR_BITS + (N) * TVN_BITS)) & TVN_MASK) +#define INDEX(N) (base->timer_jiffies >> (TVR_BITS + N * TVN_BITS)) & TVN_MASK static inline void __run_timers(tvec_base_t *base) { @@ -419,10 +422,10 @@ 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; + struct list_head work_list = LIST_HEAD_INIT(work_list); struct list_head *head = &work_list; int index = base->timer_jiffies & TVR_MASK; - + /* * Cascade timers: */ @@ -431,8 +434,8 @@ 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_replace_init(base->tv1.vec + index, &work_list); + ++base->timer_jiffies; + list_splice_init(base->tv1.vec + index, &work_list); while (!list_empty(head)) { void (*fn)(unsigned long); unsigned long data; @@ -541,6 +544,22 @@ 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; + /* * It can happen that other CPUs service timer IRQs and increment * jiffies, but we have not yet got a local timer tick to process @@ -601,6 +620,7 @@ 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) */ @@ -750,14 +770,27 @@ static long adjtime_adjustment(void) } /* in the NTP reference this is called "hardclock()" */ -static void update_ntp_one_tick(void) +static void update_wall_time_one_tick(void) { - long time_adjust_step; + long time_adjust_step, delta_nsec; 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) { @@ -770,404 +803,36 @@ static void update_ntp_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 shifted by the - * specified number of bits to the right of the binary point. + * The return value is in fixed-point nanoseconds with SHIFT_SCALE-10 + * 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 -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(); - - 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); -} - - -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 - * 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); - 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"), -}; - -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; + return ((u64) delta_nsec << (SHIFT_SCALE - 10)) + time_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. + * 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 */ -static void clocksource_adjust(struct clocksource *clock, s64 offset) +static void update_wall_time(unsigned long ticks) { - 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; + do { + ticks--; + update_wall_time_one_tick(); + if (xtime.tv_nsec >= 1000000000) { + xtime.tv_nsec -= 1000000000; 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); - } + } while (ticks); } /* @@ -1238,7 +903,7 @@ unsigned long wall_jiffies = INITIAL_JIFFIES; * playing with xtime and avenrun. */ #ifndef ARCH_HAVE_XTIME_LOCK -__cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock); +seqlock_t xtime_lock __cacheline_aligned_in_smp = SEQLOCK_UNLOCKED; EXPORT_SYMBOL(xtime_lock); #endif @@ -1273,8 +938,10 @@ static inline void update_times(void) unsigned long ticks; ticks = jiffies - wall_jiffies; - wall_jiffies += ticks; - update_wall_time(); + if (ticks) { + wall_jiffies += ticks; + update_wall_time(ticks); + } calc_load(ticks); } @@ -1378,7 +1045,7 @@ asmlinkage long sys_getegid(void) static void process_timeout(unsigned long __data) { - wake_up_process((struct task_struct *)__data); + wake_up_process((task_t *)__data); } /** @@ -1571,13 +1238,6 @@ asmlinkage long sys_sysinfo(struct sysinfo __user *info) 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; @@ -1613,8 +1273,6 @@ static int __devinit init_timers_cpu(int cpu) } 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); @@ -1673,7 +1331,7 @@ static void __devinit migrate_timers(int cpu) } #endif /* CONFIG_HOTPLUG_CPU */ -static int __cpuinit timer_cpu_notify(struct notifier_block *self, +static int timer_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) { long cpu = (long)hcpu; @@ -1693,7 +1351,7 @@ static int __cpuinit timer_cpu_notify(struct notifier_block *self, return NOTIFY_OK; } -static struct notifier_block __cpuinitdata timers_nb = { +static struct notifier_block timers_nb = { .notifier_call = timer_cpu_notify, };