| /* |
| * linux/kernel/timer.c |
| * |
| * Kernel internal timers, kernel timekeeping, basic process system calls |
| * |
| * Copyright (C) 1991, 1992 Linus Torvalds |
| * |
| * 1997-01-28 Modified by Finn Arne Gangstad to make timers scale better. |
| * |
| * 1997-09-10 Updated NTP code according to technical memorandum Jan '96 |
| * "A Kernel Model for Precision Timekeeping" by Dave Mills |
| * 1998-12-24 Fixed a xtime SMP race (we need the xtime_lock rw spinlock to |
| * serialize accesses to xtime/lost_ticks). |
| * Copyright (C) 1998 Andrea Arcangeli |
| * 1999-03-10 Improved NTP compatibility by Ulrich Windl |
| * 2002-05-31 Move sys_sysinfo here and make its locking sane, Robert Love |
| * 2000-10-05 Implemented scalable SMP per-CPU timer handling. |
| * Copyright (C) 2000, 2001, 2002 Ingo Molnar |
| * Designed by David S. Miller, Alexey Kuznetsov and Ingo Molnar |
| */ |
| |
| #include <linux/kernel_stat.h> |
| #include <linux/module.h> |
| #include <linux/interrupt.h> |
| #include <linux/percpu.h> |
| #include <linux/init.h> |
| #include <linux/mm.h> |
| #include <linux/swap.h> |
| #include <linux/notifier.h> |
| #include <linux/thread_info.h> |
| #include <linux/time.h> |
| #include <linux/jiffies.h> |
| #include <linux/posix-timers.h> |
| #include <linux/cpu.h> |
| #include <linux/syscalls.h> |
| #include <linux/delay.h> |
| |
| #include <asm/uaccess.h> |
| #include <asm/unistd.h> |
| #include <asm/div64.h> |
| #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); |
| |
| /* |
| * per-CPU timer vector definitions: |
| */ |
| #define TVN_BITS (CONFIG_BASE_SMALL ? 4 : 6) |
| #define TVR_BITS (CONFIG_BASE_SMALL ? 6 : 8) |
| #define TVN_SIZE (1 << TVN_BITS) |
| #define TVR_SIZE (1 << TVR_BITS) |
| #define TVN_MASK (TVN_SIZE - 1) |
| #define TVR_MASK (TVR_SIZE - 1) |
| |
| typedef struct tvec_s { |
| struct list_head vec[TVN_SIZE]; |
| } tvec_t; |
| |
| typedef struct tvec_root_s { |
| struct list_head vec[TVR_SIZE]; |
| } tvec_root_t; |
| |
| struct tvec_t_base_s { |
| spinlock_t lock; |
| struct timer_list *running_timer; |
| unsigned long timer_jiffies; |
| tvec_root_t tv1; |
| tvec_t tv2; |
| tvec_t tv3; |
| tvec_t tv4; |
| tvec_t tv5; |
| } ____cacheline_aligned_in_smp; |
| |
| typedef struct tvec_t_base_s tvec_base_t; |
| static DEFINE_PER_CPU(tvec_base_t *, tvec_bases); |
| tvec_base_t boot_tvec_bases; |
| EXPORT_SYMBOL(boot_tvec_bases); |
| |
| static inline void set_running_timer(tvec_base_t *base, |
| struct timer_list *timer) |
| { |
| #ifdef CONFIG_SMP |
| base->running_timer = timer; |
| #endif |
| } |
| |
| static void internal_add_timer(tvec_base_t *base, struct timer_list *timer) |
| { |
| unsigned long expires = timer->expires; |
| unsigned long idx = expires - base->timer_jiffies; |
| struct list_head *vec; |
| |
| if (idx < TVR_SIZE) { |
| int i = expires & TVR_MASK; |
| vec = base->tv1.vec + i; |
| } else if (idx < 1 << (TVR_BITS + TVN_BITS)) { |
| int i = (expires >> TVR_BITS) & TVN_MASK; |
| vec = base->tv2.vec + i; |
| } else if (idx < 1 << (TVR_BITS + 2 * TVN_BITS)) { |
| int i = (expires >> (TVR_BITS + TVN_BITS)) & TVN_MASK; |
| vec = base->tv3.vec + i; |
| } else if (idx < 1 << (TVR_BITS + 3 * TVN_BITS)) { |
| int i = (expires >> (TVR_BITS + 2 * TVN_BITS)) & TVN_MASK; |
| vec = base->tv4.vec + i; |
| } else if ((signed long) idx < 0) { |
| /* |
| * Can happen if you add a timer with expires == jiffies, |
| * or you set a timer to go off in the past |
| */ |
| vec = base->tv1.vec + (base->timer_jiffies & TVR_MASK); |
| } else { |
| int i; |
| /* If the timeout is larger than 0xffffffff on 64-bit |
| * architectures then we use the maximum timeout: |
| */ |
| if (idx > 0xffffffffUL) { |
| idx = 0xffffffffUL; |
| expires = idx + base->timer_jiffies; |
| } |
| i = (expires >> (TVR_BITS + 3 * TVN_BITS)) & TVN_MASK; |
| vec = base->tv5.vec + i; |
| } |
| /* |
| * Timers are FIFO: |
| */ |
| list_add_tail(&timer->entry, vec); |
| } |
| |
| /*** |
| * init_timer - initialize a timer. |
| * @timer: the timer to be initialized |
| * |
| * init_timer() must be done to a timer prior calling *any* of the |
| * other timer functions. |
| */ |
| void fastcall init_timer(struct timer_list *timer) |
| { |
| timer->entry.next = NULL; |
| timer->base = per_cpu(tvec_bases, raw_smp_processor_id()); |
| } |
| EXPORT_SYMBOL(init_timer); |
| |
| static inline void detach_timer(struct timer_list *timer, |
| int clear_pending) |
| { |
| struct list_head *entry = &timer->entry; |
| |
| __list_del(entry->prev, entry->next); |
| if (clear_pending) |
| entry->next = NULL; |
| entry->prev = LIST_POISON2; |
| } |
| |
| /* |
| * We are using hashed locking: holding per_cpu(tvec_bases).lock |
| * means that all timers which are tied to this base via timer->base are |
| * locked, and the base itself is locked too. |
| * |
| * So __run_timers/migrate_timers can safely modify all timers which could |
| * be found on ->tvX lists. |
| * |
| * When the timer's base is locked, and the timer removed from list, it is |
| * possible to set timer->base = NULL and drop the lock: the timer remains |
| * locked. |
| */ |
| static tvec_base_t *lock_timer_base(struct timer_list *timer, |
| unsigned long *flags) |
| { |
| tvec_base_t *base; |
| |
| for (;;) { |
| base = timer->base; |
| if (likely(base != NULL)) { |
| spin_lock_irqsave(&base->lock, *flags); |
| if (likely(base == timer->base)) |
| return base; |
| /* The timer has migrated to another CPU */ |
| spin_unlock_irqrestore(&base->lock, *flags); |
| } |
| cpu_relax(); |
| } |
| } |
| |
| int __mod_timer(struct timer_list *timer, unsigned long expires) |
| { |
| tvec_base_t *base, *new_base; |
| unsigned long flags; |
| int ret = 0; |
| |
| BUG_ON(!timer->function); |
| |
| base = lock_timer_base(timer, &flags); |
| |
| if (timer_pending(timer)) { |
| detach_timer(timer, 0); |
| ret = 1; |
| } |
| |
| new_base = __get_cpu_var(tvec_bases); |
| |
| if (base != new_base) { |
| /* |
| * We are trying to schedule the timer on the local CPU. |
| * However we can't change timer's base while it is running, |
| * otherwise del_timer_sync() can't detect that the timer's |
| * handler yet has not finished. This also guarantees that |
| * the timer is serialized wrt itself. |
| */ |
| if (likely(base->running_timer != timer)) { |
| /* See the comment in lock_timer_base() */ |
| timer->base = NULL; |
| spin_unlock(&base->lock); |
| base = new_base; |
| spin_lock(&base->lock); |
| timer->base = base; |
| } |
| } |
| |
| timer->expires = expires; |
| internal_add_timer(base, timer); |
| spin_unlock_irqrestore(&base->lock, flags); |
| |
| return ret; |
| } |
| |
| 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 |
| * |
| * This is not very scalable on SMP. Double adds are not possible. |
| */ |
| void add_timer_on(struct timer_list *timer, int cpu) |
| { |
| tvec_base_t *base = per_cpu(tvec_bases, cpu); |
| unsigned long flags; |
| |
| BUG_ON(timer_pending(timer) || !timer->function); |
| spin_lock_irqsave(&base->lock, flags); |
| timer->base = base; |
| internal_add_timer(base, timer); |
| spin_unlock_irqrestore(&base->lock, flags); |
| } |
| |
| |
| /*** |
| * mod_timer - modify a timer's timeout |
| * @timer: the timer to be modified |
| * |
| * 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) |
| * |
| * mod_timer(timer, expires) is equivalent to: |
| * |
| * del_timer(timer); timer->expires = expires; add_timer(timer); |
| * |
| * Note that if there are multiple unserialized concurrent users of the |
| * same timer, then mod_timer() is the only safe way to modify the timeout, |
| * since add_timer() cannot modify an already running timer. |
| * |
| * The function returns whether it has modified a pending timer or not. |
| * (ie. mod_timer() of an inactive timer returns 0, mod_timer() of an |
| * active timer returns 1.) |
| */ |
| int mod_timer(struct timer_list *timer, unsigned long expires) |
| { |
| BUG_ON(!timer->function); |
| |
| /* |
| * This is a common optimization triggered by the |
| * networking code - if the timer is re-modified |
| * to be the same thing then just return: |
| */ |
| if (timer->expires == expires && timer_pending(timer)) |
| return 1; |
| |
| return __mod_timer(timer, expires); |
| } |
| |
| EXPORT_SYMBOL(mod_timer); |
| |
| /*** |
| * del_timer - deactive a timer. |
| * @timer: the timer to be deactivated |
| * |
| * del_timer() deactivates a timer - this works on both active and inactive |
| * timers. |
| * |
| * The function returns whether it has deactivated a pending timer or not. |
| * (ie. del_timer() of an inactive timer returns 0, del_timer() of an |
| * active timer returns 1.) |
| */ |
| int del_timer(struct timer_list *timer) |
| { |
| tvec_base_t *base; |
| unsigned long flags; |
| int ret = 0; |
| |
| if (timer_pending(timer)) { |
| base = lock_timer_base(timer, &flags); |
| if (timer_pending(timer)) { |
| detach_timer(timer, 1); |
| ret = 1; |
| } |
| spin_unlock_irqrestore(&base->lock, flags); |
| } |
| |
| return ret; |
| } |
| |
| EXPORT_SYMBOL(del_timer); |
| |
| #ifdef CONFIG_SMP |
| /* |
| * 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. |
| * |
| * It must not be called from interrupt contexts. |
| */ |
| int try_to_del_timer_sync(struct timer_list *timer) |
| { |
| tvec_base_t *base; |
| unsigned long flags; |
| int ret = -1; |
| |
| base = lock_timer_base(timer, &flags); |
| |
| if (base->running_timer == timer) |
| goto out; |
| |
| ret = 0; |
| if (timer_pending(timer)) { |
| detach_timer(timer, 1); |
| ret = 1; |
| } |
| out: |
| spin_unlock_irqrestore(&base->lock, flags); |
| |
| return ret; |
| } |
| |
| /*** |
| * del_timer_sync - deactivate a timer and wait for the handler to finish. |
| * @timer: the timer to be deactivated |
| * |
| * This function only differs from del_timer() on SMP: besides deactivating |
| * the timer it also makes sure the handler has finished executing on other |
| * CPUs. |
| * |
| * Synchronization rules: callers must prevent restarting of the timer, |
| * otherwise this function is meaningless. It must not be called from |
| * interrupt contexts. The caller must not hold locks which would prevent |
| * completion of the timer's handler. The timer's handler must not call |
| * add_timer_on(). Upon exit the timer is not queued and the handler is |
| * not running on any CPU. |
| * |
| * The function returns whether it has deactivated a pending timer or not. |
| */ |
| int del_timer_sync(struct timer_list *timer) |
| { |
| for (;;) { |
| int ret = try_to_del_timer_sync(timer); |
| if (ret >= 0) |
| return ret; |
| } |
| } |
| |
| EXPORT_SYMBOL(del_timer_sync); |
| #endif |
| |
| 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; |
| |
| 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. |
| */ |
| 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; |
| } |
| |
| /*** |
| * __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; |
| |
| 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 *head = &work_list; |
| int index = base->timer_jiffies & TVR_MASK; |
| |
| /* |
| * Cascade timers: |
| */ |
| if (!index && |
| (!cascade(base, &base->tv2, INDEX(0))) && |
| (!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); |
| while (!list_empty(head)) { |
| void (*fn)(unsigned long); |
| unsigned long data; |
| |
| timer = list_entry(head->next,struct timer_list,entry); |
| fn = timer->function; |
| data = timer->data; |
| |
| set_running_timer(base, timer); |
| detach_timer(timer, 1); |
| spin_unlock_irq(&base->lock); |
| { |
| int preempt_count = preempt_count(); |
| fn(data); |
| if (preempt_count != preempt_count()) { |
| printk(KERN_WARNING "huh, entered %p " |
| "with preempt_count %08x, exited" |
| " with %08x?\n", |
| fn, preempt_count, |
| preempt_count()); |
| BUG(); |
| } |
| } |
| spin_lock_irq(&base->lock); |
| } |
| } |
| set_running_timer(base, NULL); |
| spin_unlock_irq(&base->lock); |
| } |
| |
| #ifdef CONFIG_NO_IDLE_HZ |
| /* |
| * Find out when the next timer event is due to happen. This |
| * is used on S/390 to stop all activity when a cpus is idle. |
| * This functions needs to be called disabled. |
| */ |
| unsigned long next_timer_interrupt(void) |
| { |
| tvec_base_t *base; |
| struct list_head *list; |
| struct timer_list *nte; |
| unsigned long expires; |
| unsigned long hr_expires = MAX_JIFFY_OFFSET; |
| ktime_t hr_delta; |
| tvec_t *varray[4]; |
| int i, j; |
| |
| hr_delta = hrtimer_get_next_event(); |
| if (hr_delta.tv64 != KTIME_MAX) { |
| struct timespec tsdelta; |
| tsdelta = ktime_to_timespec(hr_delta); |
| hr_expires = timespec_to_jiffies(&tsdelta); |
| if (hr_expires < 3) |
| return hr_expires + jiffies; |
| } |
| hr_expires += jiffies; |
| |
| base = __get_cpu_var(tvec_bases); |
| spin_lock(&base->lock); |
| expires = base->timer_jiffies + (LONG_MAX >> 1); |
| list = NULL; |
| |
| /* Look for timer events in tv1. */ |
| j = base->timer_jiffies & TVR_MASK; |
| do { |
| list_for_each_entry(nte, base->tv1.vec + j, entry) { |
| expires = nte->expires; |
| if (j < (base->timer_jiffies & TVR_MASK)) |
| list = base->tv2.vec + (INDEX(0)); |
| goto found; |
| } |
| j = (j + 1) & TVR_MASK; |
| } while (j != (base->timer_jiffies & TVR_MASK)); |
| |
| /* Check tv2-tv5. */ |
| varray[0] = &base->tv2; |
| varray[1] = &base->tv3; |
| varray[2] = &base->tv4; |
| varray[3] = &base->tv5; |
| for (i = 0; i < 4; i++) { |
| j = INDEX(i); |
| do { |
| if (list_empty(varray[i]->vec + j)) { |
| j = (j + 1) & TVN_MASK; |
| continue; |
| } |
| list_for_each_entry(nte, varray[i]->vec + j, entry) |
| if (time_before(nte->expires, expires)) |
| expires = nte->expires; |
| if (j < (INDEX(i)) && i < 3) |
| list = varray[i + 1]->vec + (INDEX(i + 1)); |
| goto found; |
| } while (j != (INDEX(i))); |
| } |
| found: |
| if (list) { |
| /* |
| * The search wrapped. We need to look at the next list |
| * from next tv element that would cascade into tv element |
| * where we found the timer element. |
| */ |
| list_for_each_entry(nte, list, entry) { |
| if (time_before(nte->expires, expires)) |
| expires = nte->expires; |
| } |
| } |
| spin_unlock(&base->lock); |
| |
| if (time_before(hr_expires, expires)) |
| return hr_expires; |
| |
| return expires; |
| } |
| #endif |
| |
| /******************************************************************/ |
| |
| /* |
| * 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 |
| * for sub jiffie times) to get to monotonic time. Monotonic is pegged |
| * at zero at system boot time, so wall_to_monotonic will be negative, |
| * however, we will ALWAYS keep the tv_nsec part positive so we can use |
| * the usual normalization. |
| */ |
| struct timespec xtime __attribute__ ((aligned (16))); |
| 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) */ |
| 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) */ |
| 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_wall_time_one_tick(void) |
| { |
| 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) { |
| 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 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; |
| |
| delta_nsec = tick_nsec + adjtime_adjustment() * 1000; |
| return ((u64) delta_nsec << (SHIFT_SCALE - 10)) + time_adj; |
| } |
| |
| /* |
| * 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 update_wall_time(unsigned long ticks) |
| { |
| do { |
| ticks--; |
| update_wall_time_one_tick(); |
| if (xtime.tv_nsec >= 1000000000) { |
| xtime.tv_nsec -= 1000000000; |
| xtime.tv_sec++; |
| second_overflow(); |
| } |
| } while (ticks); |
| } |
| |
| /* |
| * Called from the timer interrupt handler to charge one tick to the current |
| * process. user_tick is 1 if the tick is user time, 0 for system. |
| */ |
| void update_process_times(int user_tick) |
| { |
| struct task_struct *p = current; |
| int cpu = smp_processor_id(); |
| |
| /* Note: this timer irq context must be accounted for as well. */ |
| if (user_tick) |
| account_user_time(p, jiffies_to_cputime(1)); |
| else |
| account_system_time(p, HARDIRQ_OFFSET, jiffies_to_cputime(1)); |
| run_local_timers(); |
| if (rcu_pending(cpu)) |
| rcu_check_callbacks(cpu, user_tick); |
| scheduler_tick(); |
| run_posix_cpu_timers(p); |
| } |
| |
| /* |
| * Nr of active tasks - counted in fixed-point numbers |
| */ |
| static unsigned long count_active_tasks(void) |
| { |
| return (nr_running() + nr_uninterruptible()) * FIXED_1; |
| } |
| |
| /* |
| * Hmm.. Changed this, as the GNU make sources (load.c) seems to |
| * imply that avenrun[] is the standard name for this kind of thing. |
| * Nothing else seems to be standardized: the fractional size etc |
| * all seem to differ on different machines. |
| * |
| * Requires xtime_lock to access. |
| */ |
| unsigned long avenrun[3]; |
| |
| EXPORT_SYMBOL(avenrun); |
| |
| /* |
| * calc_load - given tick count, update the avenrun load estimates. |
| * This is called while holding a write_lock on xtime_lock. |
| */ |
| 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(); |
| 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. |
| */ |
| #ifndef ARCH_HAVE_XTIME_LOCK |
| seqlock_t xtime_lock __cacheline_aligned_in_smp = SEQLOCK_UNLOCKED; |
| |
| EXPORT_SYMBOL(xtime_lock); |
| #endif |
| |
| /* |
| * This function runs timers and the timer-tq in bottom half context. |
| */ |
| static void run_timer_softirq(struct softirq_action *h) |
| { |
| tvec_base_t *base = __get_cpu_var(tvec_bases); |
| |
| hrtimer_run_queues(); |
| if (time_after_eq(jiffies, base->timer_jiffies)) |
| __run_timers(base); |
| } |
| |
| /* |
| * Called by the local, per-CPU timer interrupt on SMP. |
| */ |
| void run_local_timers(void) |
| { |
| raise_softirq(TIMER_SOFTIRQ); |
| softlockup_tick(); |
| } |
| |
| /* |
| * Called by the timer interrupt. xtime_lock must already be taken |
| * by the timer IRQ! |
| */ |
| static inline void update_times(void) |
| { |
| unsigned long ticks; |
| |
| ticks = jiffies - wall_jiffies; |
| if (ticks) { |
| wall_jiffies += ticks; |
| update_wall_time(ticks); |
| } |
| calc_load(ticks); |
| } |
| |
| /* |
| * The 64-bit jiffies value is not atomic - you MUST NOT read it |
| * without sampling the sequence number in xtime_lock. |
| * jiffies is defined in the linker script... |
| */ |
| |
| void do_timer(struct pt_regs *regs) |
| { |
| jiffies_64++; |
| /* prevent loading jiffies before storing new jiffies_64 value. */ |
| barrier(); |
| update_times(); |
| } |
| |
| #ifdef __ARCH_WANT_SYS_ALARM |
| |
| /* |
| * For backwards compatibility? This can be done in libc so Alpha |
| * and all newer ports shouldn't need it. |
| */ |
| asmlinkage unsigned long sys_alarm(unsigned int seconds) |
| { |
| return alarm_setitimer(seconds); |
| } |
| |
| #endif |
| |
| #ifndef __alpha__ |
| |
| /* |
| * The Alpha uses getxpid, getxuid, and getxgid instead. Maybe this |
| * should be moved into arch/i386 instead? |
| */ |
| |
| /** |
| * sys_getpid - return the thread group id of the current process |
| * |
| * Note, despite the name, this returns the tgid not the pid. The tgid and |
| * the pid are identical unless CLONE_THREAD was specified on clone() in |
| * which case the tgid is the same in all threads of the same group. |
| * |
| * This is SMP safe as current->tgid does not change. |
| */ |
| asmlinkage long sys_getpid(void) |
| { |
| return current->tgid; |
| } |
| |
| /* |
| * Accessing ->group_leader->real_parent is not SMP-safe, it could |
| * change from under us. However, rather than getting any lock |
| * we can use an optimistic algorithm: get the parent |
| * pid, and go back and check that the parent is still |
| * the same. If it has changed (which is extremely unlikely |
| * indeed), we just try again.. |
| * |
| * NOTE! This depends on the fact that even if we _do_ |
| * get an old value of "parent", we can happily dereference |
| * the pointer (it was and remains a dereferencable kernel pointer |
| * no matter what): we just can't necessarily trust the result |
| * until we know that the parent pointer is valid. |
| * |
| * NOTE2: ->group_leader never changes from under us. |
| */ |
| asmlinkage long sys_getppid(void) |
| { |
| int pid; |
| struct task_struct *me = current; |
| struct task_struct *parent; |
| |
| parent = me->group_leader->real_parent; |
| for (;;) { |
| pid = parent->tgid; |
| #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT) |
| { |
| struct task_struct *old = parent; |
| |
| /* |
| * Make sure we read the pid before re-reading the |
| * parent pointer: |
| */ |
| smp_rmb(); |
| parent = me->group_leader->real_parent; |
| if (old != parent) |
| continue; |
| } |
| #endif |
| break; |
| } |
| return pid; |
| } |
| |
| asmlinkage long sys_getuid(void) |
| { |
| /* Only we change this so SMP safe */ |
| return current->uid; |
| } |
| |
| asmlinkage long sys_geteuid(void) |
| { |
| /* Only we change this so SMP safe */ |
| return current->euid; |
| } |
| |
| asmlinkage long sys_getgid(void) |
| { |
| /* Only we change this so SMP safe */ |
| return current->gid; |
| } |
| |
| asmlinkage long sys_getegid(void) |
| { |
| /* Only we change this so SMP safe */ |
| return current->egid; |
| } |
| |
| #endif |
| |
| static void process_timeout(unsigned long __data) |
| { |
| wake_up_process((task_t *)__data); |
| } |
| |
| /** |
| * schedule_timeout - sleep until timeout |
| * @timeout: timeout value in jiffies |
| * |
| * Make the current task sleep until @timeout jiffies have |
| * elapsed. The routine will return immediately unless |
| * the current task state has been set (see set_current_state()). |
| * |
| * You can set the task state as follows - |
| * |
| * %TASK_UNINTERRUPTIBLE - at least @timeout jiffies are guaranteed to |
| * pass before the routine returns. The routine will return 0 |
| * |
| * %TASK_INTERRUPTIBLE - the routine may return early if a signal is |
| * delivered to the current task. In this case the remaining time |
| * in jiffies will be returned, or 0 if the timer expired in time |
| * |
| * The current task state is guaranteed to be TASK_RUNNING when this |
| * routine returns. |
| * |
| * Specifying a @timeout value of %MAX_SCHEDULE_TIMEOUT will schedule |
| * the CPU away without a bound on the timeout. In this case the return |
| * value will be %MAX_SCHEDULE_TIMEOUT. |
| * |
| * In all cases the return value is guaranteed to be non-negative. |
| */ |
| fastcall signed long __sched schedule_timeout(signed long timeout) |
| { |
| struct timer_list timer; |
| unsigned long expire; |
| |
| switch (timeout) |
| { |
| case MAX_SCHEDULE_TIMEOUT: |
| /* |
| * These two special cases are useful to be comfortable |
| * in the caller. Nothing more. We could take |
| * MAX_SCHEDULE_TIMEOUT from one of the negative value |
| * but I' d like to return a valid offset (>=0) to allow |
| * the caller to do everything it want with the retval. |
| */ |
| schedule(); |
| goto out; |
| default: |
| /* |
| * Another bit of PARANOID. Note that the retval will be |
| * 0 since no piece of kernel is supposed to do a check |
| * for a negative retval of schedule_timeout() (since it |
| * should never happens anyway). You just have the printk() |
| * that will tell you if something is gone wrong and where. |
| */ |
| if (timeout < 0) |
| { |
| printk(KERN_ERR "schedule_timeout: wrong timeout " |
| "value %lx from %p\n", timeout, |
| __builtin_return_address(0)); |
| current->state = TASK_RUNNING; |
| goto out; |
| } |
| } |
| |
| expire = timeout + jiffies; |
| |
| setup_timer(&timer, process_timeout, (unsigned long)current); |
| __mod_timer(&timer, expire); |
| schedule(); |
| del_singleshot_timer_sync(&timer); |
| |
| timeout = expire - jiffies; |
| |
| out: |
| return timeout < 0 ? 0 : timeout; |
| } |
| EXPORT_SYMBOL(schedule_timeout); |
| |
| /* |
| * We can use __set_current_state() here because schedule_timeout() calls |
| * schedule() unconditionally. |
| */ |
| signed long __sched schedule_timeout_interruptible(signed long timeout) |
| { |
| __set_current_state(TASK_INTERRUPTIBLE); |
| return schedule_timeout(timeout); |
| } |
| EXPORT_SYMBOL(schedule_timeout_interruptible); |
| |
| signed long __sched schedule_timeout_uninterruptible(signed long timeout) |
| { |
| __set_current_state(TASK_UNINTERRUPTIBLE); |
| return schedule_timeout(timeout); |
| } |
| EXPORT_SYMBOL(schedule_timeout_uninterruptible); |
| |
| /* Thread ID - the internal kernel "pid" */ |
| asmlinkage long sys_gettid(void) |
| { |
| return current->pid; |
| } |
| |
| /* |
| * sys_sysinfo - fill in sysinfo struct |
| */ |
| asmlinkage long sys_sysinfo(struct sysinfo __user *info) |
| { |
| struct sysinfo val; |
| unsigned long mem_total, sav_total; |
| unsigned int mem_unit, bitcount; |
| unsigned long seq; |
| |
| memset((char *)&val, 0, sizeof(struct sysinfo)); |
| |
| do { |
| struct timespec tp; |
| seq = read_seqbegin(&xtime_lock); |
| |
| /* |
| * This is annoying. The below is the same thing |
| * posix_get_clock_monotonic() does, but it wants to |
| * take the lock which we want to cover the loads stuff |
| * too. |
| */ |
| |
| getnstimeofday(&tp); |
| tp.tv_sec += wall_to_monotonic.tv_sec; |
| tp.tv_nsec += wall_to_monotonic.tv_nsec; |
| if (tp.tv_nsec - NSEC_PER_SEC >= 0) { |
| tp.tv_nsec = tp.tv_nsec - NSEC_PER_SEC; |
| tp.tv_sec++; |
| } |
| val.uptime = tp.tv_sec + (tp.tv_nsec ? 1 : 0); |
| |
| val.loads[0] = avenrun[0] << (SI_LOAD_SHIFT - FSHIFT); |
| val.loads[1] = avenrun[1] << (SI_LOAD_SHIFT - FSHIFT); |
| val.loads[2] = avenrun[2] << (SI_LOAD_SHIFT - FSHIFT); |
| |
| val.procs = nr_threads; |
| } while (read_seqretry(&xtime_lock, seq)); |
| |
| si_meminfo(&val); |
| si_swapinfo(&val); |
| |
| /* |
| * If the sum of all the available memory (i.e. ram + swap) |
| * is less than can be stored in a 32 bit unsigned long then |
| * we can be binary compatible with 2.2.x kernels. If not, |
| * well, in that case 2.2.x was broken anyways... |
| * |
| * -Erik Andersen <andersee@debian.org> |
| */ |
| |
| mem_total = val.totalram + val.totalswap; |
| if (mem_total < val.totalram || mem_total < val.totalswap) |
| goto out; |
| bitcount = 0; |
| mem_unit = val.mem_unit; |
| while (mem_unit > 1) { |
| bitcount++; |
| mem_unit >>= 1; |
| sav_total = mem_total; |
| mem_total <<= 1; |
| if (mem_total < sav_total) |
| goto out; |
| } |
| |
| /* |
| * If mem_total did not overflow, multiply all memory values by |
| * val.mem_unit and set it to 1. This leaves things compatible |
| * with 2.2.x, and also retains compatibility with earlier 2.4.x |
| * kernels... |
| */ |
| |
| val.mem_unit = 1; |
| val.totalram <<= bitcount; |
| val.freeram <<= bitcount; |
| val.sharedram <<= bitcount; |
| val.bufferram <<= bitcount; |
| val.totalswap <<= bitcount; |
| val.freeswap <<= bitcount; |
| val.totalhigh <<= bitcount; |
| val.freehigh <<= bitcount; |
| |
| out: |
| if (copy_to_user(info, &val, sizeof(struct sysinfo))) |
| return -EFAULT; |
| |
| return 0; |
| } |
| |
| static int __devinit init_timers_cpu(int cpu) |
| { |
| int j; |
| tvec_base_t *base; |
| |
| base = per_cpu(tvec_bases, cpu); |
| if (!base) { |
| static char boot_done; |
| |
| /* |
| * Cannot do allocation in init_timers as that runs before the |
| * allocator initializes (and would waste memory if there are |
| * more possible CPUs than will ever be installed/brought up). |
| */ |
| if (boot_done) { |
| base = kmalloc_node(sizeof(*base), GFP_KERNEL, |
| cpu_to_node(cpu)); |
| if (!base) |
| return -ENOMEM; |
| memset(base, 0, sizeof(*base)); |
| } else { |
| base = &boot_tvec_bases; |
| boot_done = 1; |
| } |
| per_cpu(tvec_bases, cpu) = base; |
| } |
| spin_lock_init(&base->lock); |
| for (j = 0; j < TVN_SIZE; j++) { |
| INIT_LIST_HEAD(base->tv5.vec + j); |
| INIT_LIST_HEAD(base->tv4.vec + j); |
| INIT_LIST_HEAD(base->tv3.vec + j); |
| INIT_LIST_HEAD(base->tv2.vec + j); |
| } |
| for (j = 0; j < TVR_SIZE; j++) |
| INIT_LIST_HEAD(base->tv1.vec + j); |
| |
| base->timer_jiffies = jiffies; |
| return 0; |
| } |
| |
| #ifdef CONFIG_HOTPLUG_CPU |
| static void migrate_timer_list(tvec_base_t *new_base, struct list_head *head) |
| { |
| struct timer_list *timer; |
| |
| while (!list_empty(head)) { |
| timer = list_entry(head->next, struct timer_list, entry); |
| detach_timer(timer, 0); |
| timer->base = new_base; |
| internal_add_timer(new_base, timer); |
| } |
| } |
| |
| static void __devinit migrate_timers(int cpu) |
| { |
| tvec_base_t *old_base; |
| tvec_base_t *new_base; |
| int i; |
| |
| BUG_ON(cpu_online(cpu)); |
| old_base = per_cpu(tvec_bases, cpu); |
| new_base = get_cpu_var(tvec_bases); |
| |
| local_irq_disable(); |
| spin_lock(&new_base->lock); |
| spin_lock(&old_base->lock); |
| |
| BUG_ON(old_base->running_timer); |
| |
| for (i = 0; i < TVR_SIZE; i++) |
| migrate_timer_list(new_base, old_base->tv1.vec + i); |
| for (i = 0; i < TVN_SIZE; i++) { |
| migrate_timer_list(new_base, old_base->tv2.vec + i); |
| migrate_timer_list(new_base, old_base->tv3.vec + i); |
| migrate_timer_list(new_base, old_base->tv4.vec + i); |
| migrate_timer_list(new_base, old_base->tv5.vec + i); |
| } |
| |
| spin_unlock(&old_base->lock); |
| spin_unlock(&new_base->lock); |
| local_irq_enable(); |
| put_cpu_var(tvec_bases); |
| } |
| #endif /* CONFIG_HOTPLUG_CPU */ |
| |
| static int __devinit timer_cpu_notify(struct notifier_block *self, |
| unsigned long action, void *hcpu) |
| { |
| long cpu = (long)hcpu; |
| switch(action) { |
| case CPU_UP_PREPARE: |
| if (init_timers_cpu(cpu) < 0) |
| return NOTIFY_BAD; |
| break; |
| #ifdef CONFIG_HOTPLUG_CPU |
| case CPU_DEAD: |
| migrate_timers(cpu); |
| break; |
| #endif |
| default: |
| break; |
| } |
| return NOTIFY_OK; |
| } |
| |
| static struct notifier_block __devinitdata timers_nb = { |
| .notifier_call = timer_cpu_notify, |
| }; |
| |
| |
| void __init init_timers(void) |
| { |
| timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE, |
| (void *)(long)smp_processor_id()); |
| register_cpu_notifier(&timers_nb); |
| open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL); |
| } |
| |
| #ifdef CONFIG_TIME_INTERPOLATION |
| |
| struct time_interpolator *time_interpolator __read_mostly; |
| static struct time_interpolator *time_interpolator_list __read_mostly; |
| static DEFINE_SPINLOCK(time_interpolator_lock); |
| |
| static inline u64 time_interpolator_get_cycles(unsigned int src) |
| { |
| unsigned long (*x)(void); |
| |
| switch (src) |
| { |
| case TIME_SOURCE_FUNCTION: |
| x = time_interpolator->addr; |
| return x(); |
| |
| case TIME_SOURCE_MMIO64 : |
| return readq_relaxed((void __iomem *)time_interpolator->addr); |
| |
| case TIME_SOURCE_MMIO32 : |
| return readl_relaxed((void __iomem *)time_interpolator->addr); |
| |
| default: return get_cycles(); |
| } |
| } |
| |
| static inline u64 time_interpolator_get_counter(int writelock) |
| { |
| unsigned int src = time_interpolator->source; |
| |
| if (time_interpolator->jitter) |
| { |
| u64 lcycle; |
| u64 now; |
| |
| do { |
| lcycle = time_interpolator->last_cycle; |
| now = time_interpolator_get_cycles(src); |
| if (lcycle && time_after(lcycle, now)) |
| return lcycle; |
| |
| /* When holding the xtime write lock, there's no need |
| * to add the overhead of the cmpxchg. Readers are |
| * force to retry until the write lock is released. |
| */ |
| if (writelock) { |
| time_interpolator->last_cycle = now; |
| return now; |
| } |
| /* Keep track of the last timer value returned. The use of cmpxchg here |
| * will cause contention in an SMP environment. |
| */ |
| } while (unlikely(cmpxchg(&time_interpolator->last_cycle, lcycle, now) != lcycle)); |
| return now; |
| } |
| else |
| return time_interpolator_get_cycles(src); |
| } |
| |
| void time_interpolator_reset(void) |
| { |
| time_interpolator->offset = 0; |
| time_interpolator->last_counter = time_interpolator_get_counter(1); |
| } |
| |
| #define GET_TI_NSECS(count,i) (((((count) - i->last_counter) & (i)->mask) * (i)->nsec_per_cyc) >> (i)->shift) |
| |
| unsigned long time_interpolator_get_offset(void) |
| { |
| /* If we do not have a time interpolator set up then just return zero */ |
| if (!time_interpolator) |
| return 0; |
| |
| return time_interpolator->offset + |
| GET_TI_NSECS(time_interpolator_get_counter(0), time_interpolator); |
| } |
| |
| #define INTERPOLATOR_ADJUST 65536 |
| #define INTERPOLATOR_MAX_SKIP 10*INTERPOLATOR_ADJUST |
| |
| static void time_interpolator_update(long delta_nsec) |
| { |
| u64 counter; |
| unsigned long offset; |
| |
| /* If there is no time interpolator set up then do nothing */ |
| if (!time_interpolator) |
| return; |
| |
| /* |
| * The interpolator compensates for late ticks by accumulating the late |
| * time in time_interpolator->offset. A tick earlier than expected will |
| * lead to a reset of the offset and a corresponding jump of the clock |
| * forward. Again this only works if the interpolator clock is running |
| * slightly slower than the regular clock and the tuning logic insures |
| * that. |
| */ |
| |
| counter = time_interpolator_get_counter(1); |
| offset = time_interpolator->offset + |
| GET_TI_NSECS(counter, time_interpolator); |
| |
| if (delta_nsec < 0 || (unsigned long) delta_nsec < offset) |
| time_interpolator->offset = offset - delta_nsec; |
| else { |
| time_interpolator->skips++; |
| time_interpolator->ns_skipped += delta_nsec - offset; |
| time_interpolator->offset = 0; |
| } |
| time_interpolator->last_counter = counter; |
| |
| /* Tuning logic for time interpolator invoked every minute or so. |
| * Decrease interpolator clock speed if no skips occurred and an offset is carried. |
| * Increase interpolator clock speed if we skip too much time. |
| */ |
| if (jiffies % INTERPOLATOR_ADJUST == 0) |
| { |
| if (time_interpolator->skips == 0 && time_interpolator->offset > TICK_NSEC) |
| time_interpolator->nsec_per_cyc--; |
| if (time_interpolator->ns_skipped > INTERPOLATOR_MAX_SKIP && time_interpolator->offset == 0) |
| time_interpolator->nsec_per_cyc++; |
| time_interpolator->skips = 0; |
| time_interpolator->ns_skipped = 0; |
| } |
| } |
| |
| static inline int |
| is_better_time_interpolator(struct time_interpolator *new) |
| { |
| if (!time_interpolator) |
| return 1; |
| return new->frequency > 2*time_interpolator->frequency || |
| (unsigned long)new->drift < (unsigned long)time_interpolator->drift; |
| } |
| |
| void |
| register_time_interpolator(struct time_interpolator *ti) |
| { |
| unsigned long flags; |
| |
| /* Sanity check */ |
| if (ti->frequency == 0 || ti->mask == 0) |
| BUG(); |
| |
| ti->nsec_per_cyc = ((u64)NSEC_PER_SEC << ti->shift) / ti->frequency; |
| spin_lock(&time_interpolator_lock); |
| write_seqlock_irqsave(&xtime_lock, flags); |
| if (is_better_time_interpolator(ti)) { |
| time_interpolator = ti; |
| time_interpolator_reset(); |
| } |
| write_sequnlock_irqrestore(&xtime_lock, flags); |
| |
| ti->next = time_interpolator_list; |
| time_interpolator_list = ti; |
| spin_unlock(&time_interpolator_lock); |
| } |
| |
| void |
| unregister_time_interpolator(struct time_interpolator *ti) |
| { |
| struct time_interpolator *curr, **prev; |
| unsigned long flags; |
| |
| spin_lock(&time_interpolator_lock); |
| prev = &time_interpolator_list; |
| for (curr = *prev; curr; curr = curr->next) { |
| if (curr == ti) { |
| *prev = curr->next; |
| break; |
| } |
| prev = &curr->next; |
| } |
| |
| write_seqlock_irqsave(&xtime_lock, flags); |
| if (ti == time_interpolator) { |
| /* we lost the best time-interpolator: */ |
| time_interpolator = NULL; |
| /* find the next-best interpolator */ |
| for (curr = time_interpolator_list; curr; curr = curr->next) |
| if (is_better_time_interpolator(curr)) |
| time_interpolator = curr; |
| time_interpolator_reset(); |
| } |
| write_sequnlock_irqrestore(&xtime_lock, flags); |
| spin_unlock(&time_interpolator_lock); |
| } |
| #endif /* CONFIG_TIME_INTERPOLATION */ |
| |
| /** |
| * msleep - sleep safely even with waitqueue interruptions |
| * @msecs: Time in milliseconds to sleep for |
| */ |
| void msleep(unsigned int msecs) |
| { |
| unsigned long timeout = msecs_to_jiffies(msecs) + 1; |
| |
| while (timeout) |
| timeout = schedule_timeout_uninterruptible(timeout); |
| } |
| |
| EXPORT_SYMBOL(msleep); |
| |
| /** |
| * msleep_interruptible - sleep waiting for signals |
| * @msecs: Time in milliseconds to sleep for |
| */ |
| unsigned long msleep_interruptible(unsigned int msecs) |
| { |
| unsigned long timeout = msecs_to_jiffies(msecs) + 1; |
| |
| while (timeout && !signal_pending(current)) |
| timeout = schedule_timeout_interruptible(timeout); |
| return jiffies_to_msecs(timeout); |
| } |
| |
| EXPORT_SYMBOL(msleep_interruptible); |