diff options
Diffstat (limited to 'kernel/time')
-rw-r--r-- | kernel/time/clockevents.c | 46 | ||||
-rw-r--r-- | kernel/time/clocksource.c | 137 | ||||
-rw-r--r-- | kernel/time/ntp.c | 10 | ||||
-rw-r--r-- | kernel/time/tick-broadcast.c | 42 | ||||
-rw-r--r-- | kernel/time/tick-common.c | 20 | ||||
-rw-r--r-- | kernel/time/tick-internal.h | 1 | ||||
-rw-r--r-- | kernel/time/tick-oneshot.c | 4 | ||||
-rw-r--r-- | kernel/time/tick-sched.c | 141 | ||||
-rw-r--r-- | kernel/time/timecompare.c | 8 | ||||
-rw-r--r-- | kernel/time/timekeeping.c | 105 | ||||
-rw-r--r-- | kernel/time/timer_list.c | 25 | ||||
-rw-r--r-- | kernel/time/timer_stats.c | 18 |
12 files changed, 391 insertions, 166 deletions
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c index 620b58abdc32..d7395fdfb9f3 100644 --- a/kernel/time/clockevents.c +++ b/kernel/time/clockevents.c @@ -20,6 +20,8 @@ #include <linux/sysdev.h> #include <linux/tick.h> +#include "tick-internal.h" + /* The registered clock event devices */ static LIST_HEAD(clockevent_devices); static LIST_HEAD(clockevents_released); @@ -28,7 +30,7 @@ static LIST_HEAD(clockevents_released); static RAW_NOTIFIER_HEAD(clockevents_chain); /* Protection for the above */ -static DEFINE_SPINLOCK(clockevents_lock); +static DEFINE_RAW_SPINLOCK(clockevents_lock); /** * clockevents_delta2ns - Convert a latch value (device ticks) to nanoseconds @@ -37,10 +39,9 @@ static DEFINE_SPINLOCK(clockevents_lock); * * Math helper, returns latch value converted to nanoseconds (bound checked) */ -unsigned long clockevent_delta2ns(unsigned long latch, - struct clock_event_device *evt) +u64 clockevent_delta2ns(unsigned long latch, struct clock_event_device *evt) { - u64 clc = ((u64) latch << evt->shift); + u64 clc = (u64) latch << evt->shift; if (unlikely(!evt->mult)) { evt->mult = 1; @@ -50,10 +51,10 @@ unsigned long clockevent_delta2ns(unsigned long latch, do_div(clc, evt->mult); if (clc < 1000) clc = 1000; - if (clc > LONG_MAX) - clc = LONG_MAX; + if (clc > KTIME_MAX) + clc = KTIME_MAX; - return (unsigned long) clc; + return clc; } EXPORT_SYMBOL_GPL(clockevent_delta2ns); @@ -140,9 +141,9 @@ int clockevents_register_notifier(struct notifier_block *nb) unsigned long flags; int ret; - spin_lock_irqsave(&clockevents_lock, flags); + raw_spin_lock_irqsave(&clockevents_lock, flags); ret = raw_notifier_chain_register(&clockevents_chain, nb); - spin_unlock_irqrestore(&clockevents_lock, flags); + raw_spin_unlock_irqrestore(&clockevents_lock, flags); return ret; } @@ -184,13 +185,13 @@ void clockevents_register_device(struct clock_event_device *dev) BUG_ON(dev->mode != CLOCK_EVT_MODE_UNUSED); BUG_ON(!dev->cpumask); - spin_lock_irqsave(&clockevents_lock, flags); + raw_spin_lock_irqsave(&clockevents_lock, flags); list_add(&dev->list, &clockevent_devices); clockevents_do_notify(CLOCK_EVT_NOTIFY_ADD, dev); clockevents_notify_released(); - spin_unlock_irqrestore(&clockevents_lock, flags); + raw_spin_unlock_irqrestore(&clockevents_lock, flags); } EXPORT_SYMBOL_GPL(clockevents_register_device); @@ -237,10 +238,11 @@ void clockevents_exchange_device(struct clock_event_device *old, */ void clockevents_notify(unsigned long reason, void *arg) { - struct list_head *node, *tmp; + struct clock_event_device *dev, *tmp; unsigned long flags; + int cpu; - spin_lock_irqsave(&clockevents_lock, flags); + raw_spin_lock_irqsave(&clockevents_lock, flags); clockevents_do_notify(reason, arg); switch (reason) { @@ -249,13 +251,25 @@ void clockevents_notify(unsigned long reason, void *arg) * Unregister the clock event devices which were * released from the users in the notify chain. */ - list_for_each_safe(node, tmp, &clockevents_released) - list_del(node); + list_for_each_entry_safe(dev, tmp, &clockevents_released, list) + list_del(&dev->list); + /* + * Now check whether the CPU has left unused per cpu devices + */ + cpu = *((int *)arg); + list_for_each_entry_safe(dev, tmp, &clockevent_devices, list) { + if (cpumask_test_cpu(cpu, dev->cpumask) && + cpumask_weight(dev->cpumask) == 1 && + !tick_is_broadcast_device(dev)) { + BUG_ON(dev->mode != CLOCK_EVT_MODE_UNUSED); + list_del(&dev->list); + } + } break; default: break; } - spin_unlock_irqrestore(&clockevents_lock, flags); + raw_spin_unlock_irqrestore(&clockevents_lock, flags); } EXPORT_SYMBOL_GPL(clockevents_notify); #endif diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index 5e18c6ab2c6a..1f663d23e85e 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -39,7 +39,7 @@ void timecounter_init(struct timecounter *tc, tc->cycle_last = cc->read(cc); tc->nsec = start_tstamp; } -EXPORT_SYMBOL(timecounter_init); +EXPORT_SYMBOL_GPL(timecounter_init); /** * timecounter_read_delta - get nanoseconds since last call of this function @@ -83,7 +83,7 @@ u64 timecounter_read(struct timecounter *tc) return nsec; } -EXPORT_SYMBOL(timecounter_read); +EXPORT_SYMBOL_GPL(timecounter_read); u64 timecounter_cyc2time(struct timecounter *tc, cycle_t cycle_tstamp) @@ -105,7 +105,60 @@ u64 timecounter_cyc2time(struct timecounter *tc, return nsec; } -EXPORT_SYMBOL(timecounter_cyc2time); +EXPORT_SYMBOL_GPL(timecounter_cyc2time); + +/** + * clocks_calc_mult_shift - calculate mult/shift factors for scaled math of clocks + * @mult: pointer to mult variable + * @shift: pointer to shift variable + * @from: frequency to convert from + * @to: frequency to convert to + * @minsec: guaranteed runtime conversion range in seconds + * + * The function evaluates the shift/mult pair for the scaled math + * operations of clocksources and clockevents. + * + * @to and @from are frequency values in HZ. For clock sources @to is + * NSEC_PER_SEC == 1GHz and @from is the counter frequency. For clock + * event @to is the counter frequency and @from is NSEC_PER_SEC. + * + * The @minsec conversion range argument controls the time frame in + * seconds which must be covered by the runtime conversion with the + * calculated mult and shift factors. This guarantees that no 64bit + * overflow happens when the input value of the conversion is + * multiplied with the calculated mult factor. Larger ranges may + * reduce the conversion accuracy by chosing smaller mult and shift + * factors. + */ +void +clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 minsec) +{ + u64 tmp; + u32 sft, sftacc= 32; + + /* + * Calculate the shift factor which is limiting the conversion + * range: + */ + tmp = ((u64)minsec * from) >> 32; + while (tmp) { + tmp >>=1; + sftacc--; + } + + /* + * Find the conversion shift/mult pair which has the best + * accuracy and fits the maxsec conversion range: + */ + for (sft = 32; sft > 0; sft--) { + tmp = (u64) to << sft; + do_div(tmp, from); + if ((tmp >> sftacc) == 0) + break; + } + *mult = tmp; + *shift = sft; +} /*[Clocksource internal variables]--------- * curr_clocksource: @@ -290,7 +343,19 @@ static void clocksource_resume_watchdog(void) { unsigned long flags; - spin_lock_irqsave(&watchdog_lock, flags); + /* + * We use trylock here to avoid a potential dead lock when + * kgdb calls this code after the kernel has been stopped with + * watchdog_lock held. When watchdog_lock is held we just + * return and accept, that the watchdog might trigger and mark + * the monitored clock source (usually TSC) unstable. + * + * This does not affect the other caller clocksource_resume() + * because at this point the kernel is UP, interrupts are + * disabled and nothing can hold watchdog_lock. + */ + if (!spin_trylock_irqsave(&watchdog_lock, flags)) + return; clocksource_reset_watchdog(); spin_unlock_irqrestore(&watchdog_lock, flags); } @@ -388,6 +453,18 @@ static inline int clocksource_watchdog_kthread(void *data) { return 0; } #endif /* CONFIG_CLOCKSOURCE_WATCHDOG */ /** + * clocksource_suspend - suspend the clocksource(s) + */ +void clocksource_suspend(void) +{ + struct clocksource *cs; + + list_for_each_entry_reverse(cs, &clocksource_list, list) + if (cs->suspend) + cs->suspend(cs); +} + +/** * clocksource_resume - resume the clocksource(s) */ void clocksource_resume(void) @@ -396,7 +473,7 @@ void clocksource_resume(void) list_for_each_entry(cs, &clocksource_list, list) if (cs->resume) - cs->resume(); + cs->resume(cs); clocksource_resume_watchdog(); } @@ -405,14 +482,55 @@ void clocksource_resume(void) * clocksource_touch_watchdog - Update watchdog * * Update the watchdog after exception contexts such as kgdb so as not - * to incorrectly trip the watchdog. - * + * to incorrectly trip the watchdog. This might fail when the kernel + * was stopped in code which holds watchdog_lock. */ void clocksource_touch_watchdog(void) { clocksource_resume_watchdog(); } +/** + * clocksource_max_deferment - Returns max time the clocksource can be deferred + * @cs: Pointer to clocksource + * + */ +static u64 clocksource_max_deferment(struct clocksource *cs) +{ + u64 max_nsecs, max_cycles; + + /* + * Calculate the maximum number of cycles that we can pass to the + * cyc2ns function without overflowing a 64-bit signed result. The + * maximum number of cycles is equal to ULLONG_MAX/cs->mult which + * is equivalent to the below. + * max_cycles < (2^63)/cs->mult + * max_cycles < 2^(log2((2^63)/cs->mult)) + * max_cycles < 2^(log2(2^63) - log2(cs->mult)) + * max_cycles < 2^(63 - log2(cs->mult)) + * max_cycles < 1 << (63 - log2(cs->mult)) + * Please note that we add 1 to the result of the log2 to account for + * any rounding errors, ensure the above inequality is satisfied and + * no overflow will occur. + */ + max_cycles = 1ULL << (63 - (ilog2(cs->mult) + 1)); + + /* + * The actual maximum number of cycles we can defer the clocksource is + * determined by the minimum of max_cycles and cs->mask. + */ + max_cycles = min_t(u64, max_cycles, (u64) cs->mask); + max_nsecs = clocksource_cyc2ns(max_cycles, cs->mult, cs->shift); + + /* + * To ensure that the clocksource does not wrap whilst we are idle, + * limit the time the clocksource can be deferred by 12.5%. Please + * note a margin of 12.5% is used because this can be computed with + * a shift, versus say 10% which would require division. + */ + return max_nsecs - (max_nsecs >> 5); +} + #ifdef CONFIG_GENERIC_TIME /** @@ -511,6 +629,9 @@ static void clocksource_enqueue(struct clocksource *cs) */ int clocksource_register(struct clocksource *cs) { + /* calculate max idle time permitted for this clocksource */ + cs->max_idle_ns = clocksource_max_deferment(cs); + mutex_lock(&clocksource_mutex); clocksource_enqueue(cs); clocksource_select(); @@ -580,7 +701,7 @@ sysfs_show_current_clocksources(struct sys_device *dev, * @count: length of buffer * * Takes input from sysfs interface for manually overriding the default - * clocksource selction. + * clocksource selection. */ static ssize_t sysfs_override_clocksource(struct sys_device *dev, struct sysdev_attribute *attr, diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index 4800f933910e..7c0f180d6e9d 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -58,10 +58,10 @@ static s64 time_offset; static long time_constant = 2; /* maximum error (usecs): */ -long time_maxerror = NTP_PHASE_LIMIT; +static long time_maxerror = NTP_PHASE_LIMIT; /* estimated error (usecs): */ -long time_esterror = NTP_PHASE_LIMIT; +static long time_esterror = NTP_PHASE_LIMIT; /* frequency offset (scaled nsecs/secs): */ static s64 time_freq; @@ -142,11 +142,11 @@ static void ntp_update_offset(long offset) * Select how the frequency is to be controlled * and in which mode (PLL or FLL). */ - secs = xtime.tv_sec - time_reftime; + secs = get_seconds() - time_reftime; if (unlikely(time_status & STA_FREQHOLD)) secs = 0; - time_reftime = xtime.tv_sec; + time_reftime = get_seconds(); offset64 = offset; freq_adj = (offset64 * secs) << @@ -368,7 +368,7 @@ static inline void process_adj_status(struct timex *txc, struct timespec *ts) * reference time to current time. */ if (!(time_status & STA_PLL) && (txc->status & STA_PLL)) - time_reftime = xtime.tv_sec; + time_reftime = get_seconds(); /* only set allowed bits */ time_status &= STA_RONLY; diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index c2ec25087a35..b3bafd5fc66d 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -31,7 +31,7 @@ static struct tick_device tick_broadcast_device; /* FIXME: Use cpumask_var_t. */ static DECLARE_BITMAP(tick_broadcast_mask, NR_CPUS); static DECLARE_BITMAP(tmpmask, NR_CPUS); -static DEFINE_SPINLOCK(tick_broadcast_lock); +static DEFINE_RAW_SPINLOCK(tick_broadcast_lock); static int tick_broadcast_force; #ifdef CONFIG_TICK_ONESHOT @@ -96,7 +96,7 @@ int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu) unsigned long flags; int ret = 0; - spin_lock_irqsave(&tick_broadcast_lock, flags); + raw_spin_lock_irqsave(&tick_broadcast_lock, flags); /* * Devices might be registered with both periodic and oneshot @@ -122,7 +122,7 @@ int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu) tick_broadcast_clear_oneshot(cpu); } } - spin_unlock_irqrestore(&tick_broadcast_lock, flags); + raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags); return ret; } @@ -161,13 +161,13 @@ static void tick_do_broadcast(struct cpumask *mask) */ static void tick_do_periodic_broadcast(void) { - spin_lock(&tick_broadcast_lock); + raw_spin_lock(&tick_broadcast_lock); cpumask_and(to_cpumask(tmpmask), cpu_online_mask, tick_get_broadcast_mask()); tick_do_broadcast(to_cpumask(tmpmask)); - spin_unlock(&tick_broadcast_lock); + raw_spin_unlock(&tick_broadcast_lock); } /* @@ -212,7 +212,7 @@ static void tick_do_broadcast_on_off(unsigned long *reason) unsigned long flags; int cpu, bc_stopped; - spin_lock_irqsave(&tick_broadcast_lock, flags); + raw_spin_lock_irqsave(&tick_broadcast_lock, flags); cpu = smp_processor_id(); td = &per_cpu(tick_cpu_device, cpu); @@ -263,7 +263,7 @@ static void tick_do_broadcast_on_off(unsigned long *reason) tick_broadcast_setup_oneshot(bc); } out: - spin_unlock_irqrestore(&tick_broadcast_lock, flags); + raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags); } /* @@ -299,7 +299,7 @@ void tick_shutdown_broadcast(unsigned int *cpup) unsigned long flags; unsigned int cpu = *cpup; - spin_lock_irqsave(&tick_broadcast_lock, flags); + raw_spin_lock_irqsave(&tick_broadcast_lock, flags); bc = tick_broadcast_device.evtdev; cpumask_clear_cpu(cpu, tick_get_broadcast_mask()); @@ -309,7 +309,7 @@ void tick_shutdown_broadcast(unsigned int *cpup) clockevents_shutdown(bc); } - spin_unlock_irqrestore(&tick_broadcast_lock, flags); + raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags); } void tick_suspend_broadcast(void) @@ -317,13 +317,13 @@ void tick_suspend_broadcast(void) struct clock_event_device *bc; unsigned long flags; - spin_lock_irqsave(&tick_broadcast_lock, flags); + raw_spin_lock_irqsave(&tick_broadcast_lock, flags); bc = tick_broadcast_device.evtdev; if (bc) clockevents_shutdown(bc); - spin_unlock_irqrestore(&tick_broadcast_lock, flags); + raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags); } int tick_resume_broadcast(void) @@ -332,7 +332,7 @@ int tick_resume_broadcast(void) unsigned long flags; int broadcast = 0; - spin_lock_irqsave(&tick_broadcast_lock, flags); + raw_spin_lock_irqsave(&tick_broadcast_lock, flags); bc = tick_broadcast_device.evtdev; @@ -351,7 +351,7 @@ int tick_resume_broadcast(void) break; } } - spin_unlock_irqrestore(&tick_broadcast_lock, flags); + raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags); return broadcast; } @@ -405,7 +405,7 @@ static void tick_handle_oneshot_broadcast(struct clock_event_device *dev) ktime_t now, next_event; int cpu; - spin_lock(&tick_broadcast_lock); + raw_spin_lock(&tick_broadcast_lock); again: dev->next_event.tv64 = KTIME_MAX; next_event.tv64 = KTIME_MAX; @@ -443,7 +443,7 @@ again: if (tick_broadcast_set_event(next_event, 0)) goto again; } - spin_unlock(&tick_broadcast_lock); + raw_spin_unlock(&tick_broadcast_lock); } /* @@ -457,7 +457,7 @@ void tick_broadcast_oneshot_control(unsigned long reason) unsigned long flags; int cpu; - spin_lock_irqsave(&tick_broadcast_lock, flags); + raw_spin_lock_irqsave(&tick_broadcast_lock, flags); /* * Periodic mode does not care about the enter/exit of power @@ -492,7 +492,7 @@ void tick_broadcast_oneshot_control(unsigned long reason) } out: - spin_unlock_irqrestore(&tick_broadcast_lock, flags); + raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags); } /* @@ -563,13 +563,13 @@ void tick_broadcast_switch_to_oneshot(void) struct clock_event_device *bc; unsigned long flags; - spin_lock_irqsave(&tick_broadcast_lock, flags); + raw_spin_lock_irqsave(&tick_broadcast_lock, flags); tick_broadcast_device.mode = TICKDEV_MODE_ONESHOT; bc = tick_broadcast_device.evtdev; if (bc) tick_broadcast_setup_oneshot(bc); - spin_unlock_irqrestore(&tick_broadcast_lock, flags); + raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags); } @@ -581,7 +581,7 @@ void tick_shutdown_broadcast_oneshot(unsigned int *cpup) unsigned long flags; unsigned int cpu = *cpup; - spin_lock_irqsave(&tick_broadcast_lock, flags); + raw_spin_lock_irqsave(&tick_broadcast_lock, flags); /* * Clear the broadcast mask flag for the dead cpu, but do not @@ -589,7 +589,7 @@ void tick_shutdown_broadcast_oneshot(unsigned int *cpup) */ cpumask_clear_cpu(cpu, tick_get_broadcast_oneshot_mask()); - spin_unlock_irqrestore(&tick_broadcast_lock, flags); + raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags); } /* diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c index 83c4417b6a3c..b6b898d2eeef 100644 --- a/kernel/time/tick-common.c +++ b/kernel/time/tick-common.c @@ -34,7 +34,7 @@ DEFINE_PER_CPU(struct tick_device, tick_cpu_device); ktime_t tick_next_period; ktime_t tick_period; int tick_do_timer_cpu __read_mostly = TICK_DO_TIMER_BOOT; -DEFINE_SPINLOCK(tick_device_lock); +static DEFINE_RAW_SPINLOCK(tick_device_lock); /* * Debugging: see timer_list.c @@ -209,7 +209,7 @@ static int tick_check_new_device(struct clock_event_device *newdev) int cpu, ret = NOTIFY_OK; unsigned long flags; - spin_lock_irqsave(&tick_device_lock, flags); + raw_spin_lock_irqsave(&tick_device_lock, flags); cpu = smp_processor_id(); if (!cpumask_test_cpu(cpu, newdev->cpumask)) @@ -268,7 +268,7 @@ static int tick_check_new_device(struct clock_event_device *newdev) if (newdev->features & CLOCK_EVT_FEAT_ONESHOT) tick_oneshot_notify(); - spin_unlock_irqrestore(&tick_device_lock, flags); + raw_spin_unlock_irqrestore(&tick_device_lock, flags); return NOTIFY_STOP; out_bc: @@ -278,7 +278,7 @@ out_bc: if (tick_check_broadcast_device(newdev)) ret = NOTIFY_STOP; - spin_unlock_irqrestore(&tick_device_lock, flags); + raw_spin_unlock_irqrestore(&tick_device_lock, flags); return ret; } @@ -311,7 +311,7 @@ static void tick_shutdown(unsigned int *cpup) struct clock_event_device *dev = td->evtdev; unsigned long flags; - spin_lock_irqsave(&tick_device_lock, flags); + raw_spin_lock_irqsave(&tick_device_lock, flags); td->mode = TICKDEV_MODE_PERIODIC; if (dev) { /* @@ -322,7 +322,7 @@ static void tick_shutdown(unsigned int *cpup) clockevents_exchange_device(dev, NULL); td->evtdev = NULL; } - spin_unlock_irqrestore(&tick_device_lock, flags); + raw_spin_unlock_irqrestore(&tick_device_lock, flags); } static void tick_suspend(void) @@ -330,9 +330,9 @@ static void tick_suspend(void) struct tick_device *td = &__get_cpu_var(tick_cpu_device); unsigned long flags; - spin_lock_irqsave(&tick_device_lock, flags); + raw_spin_lock_irqsave(&tick_device_lock, flags); clockevents_shutdown(td->evtdev); - spin_unlock_irqrestore(&tick_device_lock, flags); + raw_spin_unlock_irqrestore(&tick_device_lock, flags); } static void tick_resume(void) @@ -341,7 +341,7 @@ static void tick_resume(void) unsigned long flags; int broadcast = tick_resume_broadcast(); - spin_lock_irqsave(&tick_device_lock, flags); + raw_spin_lock_irqsave(&tick_device_lock, flags); clockevents_set_mode(td->evtdev, CLOCK_EVT_MODE_RESUME); if (!broadcast) { @@ -350,7 +350,7 @@ static void tick_resume(void) else tick_resume_oneshot(); } - spin_unlock_irqrestore(&tick_device_lock, flags); + raw_spin_unlock_irqrestore(&tick_device_lock, flags); } /* diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h index b1c05bf75ee0..290eefbc1f60 100644 --- a/kernel/time/tick-internal.h +++ b/kernel/time/tick-internal.h @@ -6,7 +6,6 @@ #define TICK_DO_TIMER_BOOT -2 DECLARE_PER_CPU(struct tick_device, tick_cpu_device); -extern spinlock_t tick_device_lock; extern ktime_t tick_next_period; extern ktime_t tick_period; extern int tick_do_timer_cpu __read_mostly; diff --git a/kernel/time/tick-oneshot.c b/kernel/time/tick-oneshot.c index a96c0e2b89cf..0a8a213016f0 100644 --- a/kernel/time/tick-oneshot.c +++ b/kernel/time/tick-oneshot.c @@ -50,9 +50,9 @@ int tick_dev_program_event(struct clock_event_device *dev, ktime_t expires, dev->min_delta_ns += dev->min_delta_ns >> 1; printk(KERN_WARNING - "CE: %s increasing min_delta_ns to %lu nsec\n", + "CE: %s increasing min_delta_ns to %llu nsec\n", dev->name ? dev->name : "?", - dev->min_delta_ns << 1); + (unsigned long long) dev->min_delta_ns << 1); i = 0; } diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 89aed5933ed4..f992762d7f51 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -134,18 +134,13 @@ __setup("nohz=", setup_tick_nohz); * value. We do this unconditionally on any cpu, as we don't know whether the * cpu, which has the update task assigned is in a long sleep. */ -static void tick_nohz_update_jiffies(void) +static void tick_nohz_update_jiffies(ktime_t now) { int cpu = smp_processor_id(); struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu); unsigned long flags; - ktime_t now; - - if (!ts->tick_stopped) - return; cpumask_clear_cpu(cpu, nohz_cpu_mask); - now = ktime_get(); ts->idle_waketime = now; local_irq_save(flags); @@ -155,20 +150,17 @@ static void tick_nohz_update_jiffies(void) touch_softlockup_watchdog(); } -static void tick_nohz_stop_idle(int cpu) +static void tick_nohz_stop_idle(int cpu, ktime_t now) { struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu); + ktime_t delta; - if (ts->idle_active) { - ktime_t now, delta; - now = ktime_get(); - delta = ktime_sub(now, ts->idle_entrytime); - ts->idle_lastupdate = now; - ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta); - ts->idle_active = 0; + delta = ktime_sub(now, ts->idle_entrytime); + ts->idle_lastupdate = now; + ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta); + ts->idle_active = 0; - sched_clock_idle_wakeup_event(0); - } + sched_clock_idle_wakeup_event(0); } static ktime_t tick_nohz_start_idle(struct tick_sched *ts) @@ -216,6 +208,7 @@ void tick_nohz_stop_sched_tick(int inidle) struct tick_sched *ts; ktime_t last_update, expires, now; struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev; + u64 time_delta; int cpu; local_irq_save(flags); @@ -263,7 +256,7 @@ void tick_nohz_stop_sched_tick(int inidle) if (ratelimit < 10) { printk(KERN_ERR "NOHZ: local_softirq_pending %02x\n", - local_softirq_pending()); + (unsigned int) local_softirq_pending()); ratelimit++; } goto end; @@ -275,14 +268,18 @@ void tick_nohz_stop_sched_tick(int inidle) seq = read_seqbegin(&xtime_lock); last_update = last_jiffies_update; last_jiffies = jiffies; + time_delta = timekeeping_max_deferment(); } while (read_seqretry(&xtime_lock, seq)); - /* Get the next timer wheel timer */ - next_jiffies = get_next_timer_interrupt(last_jiffies); - delta_jiffies = next_jiffies - last_jiffies; - - if (rcu_needs_cpu(cpu) || printk_needs_cpu(cpu)) + if (rcu_needs_cpu(cpu) || printk_needs_cpu(cpu) || + arch_needs_cpu(cpu)) { + next_jiffies = last_jiffies + 1; delta_jiffies = 1; + } else { + /* Get the next timer wheel timer */ + next_jiffies = get_next_timer_interrupt(last_jiffies); + delta_jiffies = next_jiffies - last_jiffies; + } /* * Do not stop the tick, if we are only one off * or if the cpu is required for rcu @@ -294,22 +291,51 @@ void tick_nohz_stop_sched_tick(int inidle) if ((long)delta_jiffies >= 1) { /* - * calculate the expiry time for the next timer wheel - * timer - */ - expires = ktime_add_ns(last_update, tick_period.tv64 * - delta_jiffies); - - /* * If this cpu is the one which updates jiffies, then * give up the assignment and let it be taken by the * cpu which runs the tick timer next, which might be * this cpu as well. If we don't drop this here the * jiffies might be stale and do_timer() never - * invoked. + * invoked. Keep track of the fact that it was the one + * which had the do_timer() duty last. If this cpu is + * the one which had the do_timer() duty last, we + * limit the sleep time to the timekeeping + * max_deferement value which we retrieved + * above. Otherwise we can sleep as long as we want. */ - if (cpu == tick_do_timer_cpu) + if (cpu == tick_do_timer_cpu) { tick_do_timer_cpu = TICK_DO_TIMER_NONE; + ts->do_timer_last = 1; + } else if (tick_do_timer_cpu != TICK_DO_TIMER_NONE) { + time_delta = KTIME_MAX; + ts->do_timer_last = 0; + } else if (!ts->do_timer_last) { + time_delta = KTIME_MAX; + } + + /* + * calculate the expiry time for the next timer wheel + * timer. delta_jiffies >= NEXT_TIMER_MAX_DELTA signals + * that there is no timer pending or at least extremely + * far into the future (12 days for HZ=1000). In this + * case we set the expiry to the end of time. + */ + if (likely(delta_jiffies < NEXT_TIMER_MAX_DELTA)) { + /* + * Calculate the time delta for the next timer event. + * If the time delta exceeds the maximum time delta + * permitted by the current clocksource then adjust + * the time delta accordingly to ensure the + * clocksource does not wrap. + */ + time_delta = min_t(u64, time_delta, + tick_period.tv64 * delta_jiffies); + } + + if (time_delta < KTIME_MAX) + expires = ktime_add_ns(last_update, time_delta); + else + expires.tv64 = KTIME_MAX; if (delta_jiffies > 1) cpumask_set_cpu(cpu, nohz_cpu_mask); @@ -342,22 +368,19 @@ void tick_nohz_stop_sched_tick(int inidle) ts->idle_sleeps++; + /* Mark expires */ + ts->idle_expires = expires; + /* - * delta_jiffies >= NEXT_TIMER_MAX_DELTA signals that - * there is no timer pending or at least extremly far - * into the future (12 days for HZ=1000). In this case - * we simply stop the tick timer: + * If the expiration time == KTIME_MAX, then + * in this case we simply stop the tick timer. */ - if (unlikely(delta_jiffies >= NEXT_TIMER_MAX_DELTA)) { - ts->idle_expires.tv64 = KTIME_MAX; + if (unlikely(expires.tv64 == KTIME_MAX)) { if (ts->nohz_mode == NOHZ_MODE_HIGHRES) hrtimer_cancel(&ts->sched_timer); goto out; } - /* Mark expiries */ - ts->idle_expires = expires; - if (ts->nohz_mode == NOHZ_MODE_HIGHRES) { hrtimer_start(&ts->sched_timer, expires, HRTIMER_MODE_ABS_PINNED); @@ -436,7 +459,11 @@ void tick_nohz_restart_sched_tick(void) ktime_t now; local_irq_disable(); - tick_nohz_stop_idle(cpu); + if (ts->idle_active || (ts->inidle && ts->tick_stopped)) + now = ktime_get(); + + if (ts->idle_active) + tick_nohz_stop_idle(cpu, now); if (!ts->inidle || !ts->tick_stopped) { ts->inidle = 0; @@ -450,7 +477,6 @@ void tick_nohz_restart_sched_tick(void) /* Update jiffies first */ select_nohz_load_balancer(0); - now = ktime_get(); tick_do_update_jiffies64(now); cpumask_clear_cpu(cpu, nohz_cpu_mask); @@ -584,22 +610,18 @@ static void tick_nohz_switch_to_nohz(void) * timer and do not touch the other magic bits which need to be done * when idle is left. */ -static void tick_nohz_kick_tick(int cpu) +static void tick_nohz_kick_tick(int cpu, ktime_t now) { #if 0 /* Switch back to 2.6.27 behaviour */ struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu); - ktime_t delta, now; - - if (!ts->tick_stopped) - return; + ktime_t delta; /* * Do not touch the tick device, when the next expiry is either * already reached or less/equal than the tick period. */ - now = ktime_get(); delta = ktime_sub(hrtimer_get_expires(&ts->sched_timer), now); if (delta.tv64 <= tick_period.tv64) return; @@ -608,9 +630,26 @@ static void tick_nohz_kick_tick(int cpu) #endif } +static inline void tick_check_nohz(int cpu) +{ + struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu); + ktime_t now; + + if (!ts->idle_active && !ts->tick_stopped) + return; + now = ktime_get(); + if (ts->idle_active) + tick_nohz_stop_idle(cpu, now); + if (ts->tick_stopped) { + tick_nohz_update_jiffies(now); + tick_nohz_kick_tick(cpu, now); + } +} + #else static inline void tick_nohz_switch_to_nohz(void) { } +static inline void tick_check_nohz(int cpu) { } #endif /* NO_HZ */ @@ -620,11 +659,7 @@ static inline void tick_nohz_switch_to_nohz(void) { } void tick_check_idle(int cpu) { tick_check_oneshot_broadcast(cpu); -#ifdef CONFIG_NO_HZ - tick_nohz_stop_idle(cpu); - tick_nohz_update_jiffies(); - tick_nohz_kick_tick(cpu); -#endif + tick_check_nohz(cpu); } /* diff --git a/kernel/time/timecompare.c b/kernel/time/timecompare.c index 71e7f1a19156..12f5c55090be 100644 --- a/kernel/time/timecompare.c +++ b/kernel/time/timecompare.c @@ -40,7 +40,7 @@ ktime_t timecompare_transform(struct timecompare *sync, return ns_to_ktime(nsec); } -EXPORT_SYMBOL(timecompare_transform); +EXPORT_SYMBOL_GPL(timecompare_transform); int timecompare_offset(struct timecompare *sync, s64 *offset, @@ -89,7 +89,7 @@ int timecompare_offset(struct timecompare *sync, * source time */ sample.offset = - ktime_to_ns(ktime_add(end, start)) / 2 - + (ktime_to_ns(end) + ktime_to_ns(start)) / 2 - ts; /* simple insertion sort based on duration */ @@ -131,7 +131,7 @@ int timecompare_offset(struct timecompare *sync, return used; } -EXPORT_SYMBOL(timecompare_offset); +EXPORT_SYMBOL_GPL(timecompare_offset); void __timecompare_update(struct timecompare *sync, u64 source_tstamp) @@ -188,4 +188,4 @@ void __timecompare_update(struct timecompare *sync, } } } -EXPORT_SYMBOL(__timecompare_update); +EXPORT_SYMBOL_GPL(__timecompare_update); diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index c3a4e2907eaa..16736379a9ca 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -177,7 +177,7 @@ void timekeeping_leap_insert(int leapsecond) { xtime.tv_sec += leapsecond; wall_to_monotonic.tv_sec -= leapsecond; - update_vsyscall(&xtime, timekeeper.clock); + update_vsyscall(&xtime, timekeeper.clock, timekeeper.mult); } #ifdef CONFIG_GENERIC_TIME @@ -337,7 +337,7 @@ int do_settimeofday(struct timespec *tv) timekeeper.ntp_error = 0; ntp_clear(); - update_vsyscall(&xtime, timekeeper.clock); + update_vsyscall(&xtime, timekeeper.clock, timekeeper.mult); write_sequnlock_irqrestore(&xtime_lock, flags); @@ -488,6 +488,17 @@ int timekeeping_valid_for_hres(void) } /** + * timekeeping_max_deferment - Returns max time the clocksource can be deferred + * + * Caller must observe xtime_lock via read_seqbegin/read_seqretry to + * ensure that the clocksource does not change! + */ +u64 timekeeping_max_deferment(void) +{ + return timekeeper.clock->max_idle_ns; +} + +/** * read_persistent_clock - Return time from the persistent clock. * * Weak dummy function for arches that do not yet support it. @@ -611,6 +622,7 @@ static int timekeeping_suspend(struct sys_device *dev, pm_message_t state) write_sequnlock_irqrestore(&xtime_lock, flags); clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL); + clocksource_suspend(); return 0; } @@ -722,6 +734,51 @@ static void timekeeping_adjust(s64 offset) timekeeper.ntp_error_shift; } + +/** + * logarithmic_accumulation - shifted accumulation of cycles + * + * This functions accumulates a shifted interval of cycles into + * into a shifted interval nanoseconds. Allows for O(log) accumulation + * loop. + * + * Returns the unconsumed cycles. + */ +static cycle_t logarithmic_accumulation(cycle_t offset, int shift) +{ + u64 nsecps = (u64)NSEC_PER_SEC << timekeeper.shift; + + /* If the offset is smaller then a shifted interval, do nothing */ + if (offset < timekeeper.cycle_interval<<shift) + return offset; + + /* Accumulate one shifted interval */ + offset -= timekeeper.cycle_interval << shift; + timekeeper.clock->cycle_last += timekeeper.cycle_interval << shift; + + timekeeper.xtime_nsec += timekeeper.xtime_interval << shift; + while (timekeeper.xtime_nsec >= nsecps) { + timekeeper.xtime_nsec -= nsecps; + xtime.tv_sec++; + second_overflow(); + } + + /* Accumulate into raw time */ + raw_time.tv_nsec += timekeeper.raw_interval << shift;; + while (raw_time.tv_nsec >= NSEC_PER_SEC) { + raw_time.tv_nsec -= NSEC_PER_SEC; + raw_time.tv_sec++; + } + + /* Accumulate error between NTP and clock interval */ + timekeeper.ntp_error += tick_length << shift; + timekeeper.ntp_error -= timekeeper.xtime_interval << + (timekeeper.ntp_error_shift + shift); + + return offset; +} + + /** * update_wall_time - Uses the current clocksource to increment the wall time * @@ -732,6 +789,7 @@ void update_wall_time(void) struct clocksource *clock; cycle_t offset; u64 nsecs; + int shift = 0, maxshift; /* Make sure we're fully resumed: */ if (unlikely(timekeeping_suspended)) @@ -745,33 +803,22 @@ void update_wall_time(void) #endif timekeeper.xtime_nsec = (s64)xtime.tv_nsec << timekeeper.shift; - /* normally this loop will run just once, however in the - * case of lost or late ticks, it will accumulate correctly. + /* + * With NO_HZ we may have to accumulate many cycle_intervals + * (think "ticks") worth of time at once. To do this efficiently, + * we calculate the largest doubling multiple of cycle_intervals + * that is smaller then the offset. We then accumulate that + * chunk in one go, and then try to consume the next smaller + * doubled multiple. */ + shift = ilog2(offset) - ilog2(timekeeper.cycle_interval); + shift = max(0, shift); + /* Bound shift to one less then what overflows tick_length */ + maxshift = (8*sizeof(tick_length) - (ilog2(tick_length)+1)) - 1; + shift = min(shift, maxshift); while (offset >= timekeeper.cycle_interval) { - u64 nsecps = (u64)NSEC_PER_SEC << timekeeper.shift; - - /* accumulate one interval */ - offset -= timekeeper.cycle_interval; - clock->cycle_last += timekeeper.cycle_interval; - - timekeeper.xtime_nsec += timekeeper.xtime_interval; - if (timekeeper.xtime_nsec >= nsecps) { - timekeeper.xtime_nsec -= nsecps; - xtime.tv_sec++; - second_overflow(); - } - - raw_time.tv_nsec += timekeeper.raw_interval; - if (raw_time.tv_nsec >= NSEC_PER_SEC) { - raw_time.tv_nsec -= NSEC_PER_SEC; - raw_time.tv_sec++; - } - - /* accumulate error between NTP and clock interval */ - timekeeper.ntp_error += tick_length; - timekeeper.ntp_error -= timekeeper.xtime_interval << - timekeeper.ntp_error_shift; + offset = logarithmic_accumulation(offset, shift); + shift--; } /* correct the clock when NTP error is too big */ @@ -811,7 +858,7 @@ void update_wall_time(void) update_xtime_cache(nsecs); /* check to see if there is a new clocksource to use */ - update_vsyscall(&xtime, timekeeper.clock); + update_vsyscall(&xtime, timekeeper.clock, timekeeper.mult); } /** @@ -834,6 +881,7 @@ void getboottime(struct timespec *ts) set_normalized_timespec(ts, -boottime.tv_sec, -boottime.tv_nsec); } +EXPORT_SYMBOL_GPL(getboottime); /** * monotonic_to_bootbased - Convert the monotonic time to boot based. @@ -843,6 +891,7 @@ void monotonic_to_bootbased(struct timespec *ts) { *ts = timespec_add_safe(*ts, total_sleep_time); } +EXPORT_SYMBOL_GPL(monotonic_to_bootbased); unsigned long get_seconds(void) { diff --git a/kernel/time/timer_list.c b/kernel/time/timer_list.c index 1b5b7aa2fdfd..bdfb8dd1050c 100644 --- a/kernel/time/timer_list.c +++ b/kernel/time/timer_list.c @@ -84,7 +84,7 @@ print_active_timers(struct seq_file *m, struct hrtimer_clock_base *base, next_one: i = 0; - spin_lock_irqsave(&base->cpu_base->lock, flags); + raw_spin_lock_irqsave(&base->cpu_base->lock, flags); curr = base->first; /* @@ -100,13 +100,13 @@ next_one: timer = rb_entry(curr, struct hrtimer, node); tmp = *timer; - spin_unlock_irqrestore(&base->cpu_base->lock, flags); + raw_spin_unlock_irqrestore(&base->cpu_base->lock, flags); print_timer(m, timer, &tmp, i, now); next++; goto next_one; } - spin_unlock_irqrestore(&base->cpu_base->lock, flags); + raw_spin_unlock_irqrestore(&base->cpu_base->lock, flags); } static void @@ -150,6 +150,9 @@ static void print_cpu(struct seq_file *m, int cpu, u64 now) P_ns(expires_next); P(hres_active); P(nr_events); + P(nr_retries); + P(nr_hangs); + P_ns(max_hang_time); #endif #undef P #undef P_ns @@ -204,10 +207,12 @@ print_tickdevice(struct seq_file *m, struct tick_device *td, int cpu) return; } SEQ_printf(m, "%s\n", dev->name); - SEQ_printf(m, " max_delta_ns: %lu\n", dev->max_delta_ns); - SEQ_printf(m, " min_delta_ns: %lu\n", dev->min_delta_ns); - SEQ_printf(m, " mult: %lu\n", dev->mult); - SEQ_printf(m, " shift: %d\n", dev->shift); + SEQ_printf(m, " max_delta_ns: %llu\n", + (unsigned long long) dev->max_delta_ns); + SEQ_printf(m, " min_delta_ns: %llu\n", + (unsigned long long) dev->min_delta_ns); + SEQ_printf(m, " mult: %u\n", dev->mult); + SEQ_printf(m, " shift: %u\n", dev->shift); SEQ_printf(m, " mode: %d\n", dev->mode); SEQ_printf(m, " next_event: %Ld nsecs\n", (unsigned long long) ktime_to_ns(dev->next_event)); @@ -232,10 +237,10 @@ static void timer_list_show_tickdevices(struct seq_file *m) #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST print_tickdevice(m, tick_get_broadcast_device(), -1); SEQ_printf(m, "tick_broadcast_mask: %08lx\n", - tick_get_broadcast_mask()->bits[0]); + cpumask_bits(tick_get_broadcast_mask())[0]); #ifdef CONFIG_TICK_ONESHOT SEQ_printf(m, "tick_broadcast_oneshot_mask: %08lx\n", - tick_get_broadcast_oneshot_mask()->bits[0]); + cpumask_bits(tick_get_broadcast_oneshot_mask())[0]); #endif SEQ_printf(m, "\n"); #endif @@ -252,7 +257,7 @@ static int timer_list_show(struct seq_file *m, void *v) u64 now = ktime_to_ns(ktime_get()); int cpu; - SEQ_printf(m, "Timer List Version: v0.4\n"); + SEQ_printf(m, "Timer List Version: v0.5\n"); SEQ_printf(m, "HRTIMER_MAX_CLOCK_BASES: %d\n", HRTIMER_MAX_CLOCK_BASES); SEQ_printf(m, "now at %Ld nsecs\n", (unsigned long long)now); diff --git a/kernel/time/timer_stats.c b/kernel/time/timer_stats.c index ee5681f8d7ec..2f3b585b8d7d 100644 --- a/kernel/time/timer_stats.c +++ b/kernel/time/timer_stats.c @@ -86,7 +86,7 @@ static DEFINE_SPINLOCK(table_lock); /* * Per-CPU lookup locks for fast hash lookup: */ -static DEFINE_PER_CPU(spinlock_t, lookup_lock); +static DEFINE_PER_CPU(raw_spinlock_t, tstats_lookup_lock); /* * Mutex to serialize state changes with show-stats activities: @@ -238,14 +238,14 @@ void timer_stats_update_stats(void *timer, pid_t pid, void *startf, /* * It doesnt matter which lock we take: */ - spinlock_t *lock; + raw_spinlock_t *lock; struct entry *entry, input; unsigned long flags; if (likely(!timer_stats_active)) return; - lock = &per_cpu(lookup_lock, raw_smp_processor_id()); + lock = &per_cpu(tstats_lookup_lock, raw_smp_processor_id()); input.timer = timer; input.start_func = startf; @@ -253,7 +253,7 @@ void timer_stats_update_stats(void *timer, pid_t pid, void *startf, input.pid = pid; input.timer_flag = timer_flag; - spin_lock_irqsave(lock, flags); + raw_spin_lock_irqsave(lock, flags); if (!timer_stats_active) goto out_unlock; @@ -264,7 +264,7 @@ void timer_stats_update_stats(void *timer, pid_t pid, void *startf, atomic_inc(&overflow_count); out_unlock: - spin_unlock_irqrestore(lock, flags); + raw_spin_unlock_irqrestore(lock, flags); } static void print_name_offset(struct seq_file *m, unsigned long addr) @@ -348,9 +348,11 @@ static void sync_access(void) int cpu; for_each_online_cpu(cpu) { - spin_lock_irqsave(&per_cpu(lookup_lock, cpu), flags); + raw_spinlock_t *lock = &per_cpu(tstats_lookup_lock, cpu); + + raw_spin_lock_irqsave(lock, flags); /* nothing */ - spin_unlock_irqrestore(&per_cpu(lookup_lock, cpu), flags); + raw_spin_unlock_irqrestore(lock, flags); } } @@ -408,7 +410,7 @@ void __init init_timer_stats(void) int cpu; for_each_possible_cpu(cpu) - spin_lock_init(&per_cpu(lookup_lock, cpu)); + raw_spin_lock_init(&per_cpu(tstats_lookup_lock, cpu)); } static int __init init_tstats_procfs(void) |