| /* |
| * 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> |
| |
| 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; |
| |
| tvec_base_t boot_tvec_bases; |
| EXPORT_SYMBOL(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) |
| { |
| #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 = __raw_get_cpu_var(tvec_bases); |
| } |
| 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) |
| __acquires(timer->base->lock) |
| { |
| 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 |
| * @expires: new timeout in jiffies |
| * |
| * mod_timer is a more efficient way to update the expire field of an |
| * active timer (if the timer is inactive it will be activated) |
| * |
| * 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 |
| /** |
| * try_to_del_timer_sync - Try to deactivate a timer |
| * @timer: timer do del |
| * |
| * This function tries to deactivate a timer. Upon successful (ret >= 0) |
| * exit the timer is not queued and the handler is not running on any CPU. |
| * |
| * 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; |
| cpu_relax(); |
| } |
| } |
| |
| 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 timer_list *timer, *tmp; |
| struct list_head tv_list; |
| |
| list_replace_init(tv->vec + index, &tv_list); |
| |
| /* |
| * We are removing _all_ timers from the list, so we |
| * don't have to detach them individually. |
| */ |
| list_for_each_entry_safe(timer, tmp, &tv_list, entry) { |
| BUG_ON(timer->base != base); |
| internal_add_timer(base, timer); |
| } |
| |
| return index; |
| } |
| |
| #define INDEX(N) ((base->timer_jiffies >> (TVR_BITS + (N) * TVN_BITS)) & TVN_MASK) |
| |
| /** |
| * __run_timers - run all expired timers (if any) on this CPU. |
| * @base: the timer vector to be processed. |
| * |
| * This function cascades all vectors and executes all expired timer |
| * vectors. |
| */ |
| 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; |
| 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_replace_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); |
| |
| /* |
| * It can happen that other CPUs service timer IRQs and increment |
| * jiffies, but we have not yet got a local timer tick to process |
| * the timer wheels. In that case, the expiry time can be before |
| * jiffies, but since the high-resolution timer here is relative to |
| * jiffies, the default expression when high-resolution timers are |
| * not active, |
| * |
| * time_before(MAX_JIFFY_OFFSET + jiffies, expires) |
| * |
| * would falsely evaluate to true. If that is the case, just |
| * return jiffies so that we can immediately fire the local timer |
| */ |
| if (time_before(expires, jiffies)) |
| return jiffies; |
| |
| if (time_before(hr_expires, expires)) |
| return hr_expires; |
| |
| return expires; |
| } |
| #endif |
| |
| /******************************************************************/ |
| |
| /* |
| * 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); |
| |
| |
| /* XXX - all of this timekeeping code should be later moved to time.c */ |
| #include <linux/clocksource.h> |
| 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); |
| |
| ntp_clear(); |
| |
| clock = clocksource_get_next(); |
| clocksource_calculate_interval(clock, tick_nsec); |
| clock->cycle_last = clocksource_read(clock); |
| |
| 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/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; |
| } |
| |
| /* |
| * Adjust the multiplier to reduce the error value, |
| * this is optimized for the most common adjustments of -1,0,1, |
| * for other values we can do a bit more work. |
| */ |
| static void clocksource_adjust(struct clocksource *clock, s64 offset) |
| { |
| s64 error, interval = clock->cycle_interval; |
| int adj; |
| |
| error = clock->error >> (TICK_LENGTH_SHIFT - clock->shift - 1); |
| if (error > interval) { |
| 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; |
| xtime.tv_sec++; |
| second_overflow(); |
| } |
| |
| /* interpolator bits */ |
| time_interpolator_update(clock->xtime_interval |
| >> clock->shift); |
| |
| /* 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); |
| } |
| } |
| |
| /* |
| * 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_active() * 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; |
| |
| active_tasks = count_active_tasks(); |
| for (count -= ticks; count < 0; count += LOAD_FREQ) { |
| CALC_LOAD(avenrun[0], EXP_1, active_tasks); |
| CALC_LOAD(avenrun[1], EXP_5, active_tasks); |
| CALC_LOAD(avenrun[2], EXP_15, active_tasks); |
| } |
| } |
| |
| /* |
| * This read-write spinlock protects us from races in SMP while |
| * playing with xtime and avenrun. |
| */ |
| #ifndef ARCH_HAVE_XTIME_LOCK |
| __cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock); |
| |
| 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(unsigned long ticks) |
| { |
| update_wall_time(); |
| 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(unsigned long ticks) |
| { |
| jiffies_64 += ticks; |
| update_times(ticks); |
| } |
| |
| #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 ->real_parent is not SMP-safe, it could |
| * change from under us. However, we can use a stale |
| * value of ->real_parent under rcu_read_lock(), see |
| * release_task()->call_rcu(delayed_put_task_struct). |
| */ |
| asmlinkage long sys_getppid(void) |
| { |
| int pid; |
| |
| rcu_read_lock(); |
| pid = rcu_dereference(current->real_parent)->tgid; |
| rcu_read_unlock(); |
| |
| 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((struct task_struct *)__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 |
| * @info: pointer to buffer to fill |
| */ |
| 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; |
| } |
| |
| /* |
| * 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; |
| tvec_base_t *base; |
| static char __devinitdata tvec_base_done[NR_CPUS]; |
| |
| if (!tvec_base_done[cpu]) { |
| static char boot_done; |
| |
| if (boot_done) { |
| /* |
| * The APs use this path later in boot |
| */ |
| base = kmalloc_node(sizeof(*base), GFP_KERNEL, |
| cpu_to_node(cpu)); |
| if (!base) |
| return -ENOMEM; |
| memset(base, 0, sizeof(*base)); |
| per_cpu(tvec_bases, cpu) = base; |
| } else { |
| /* |
| * This is for the boot CPU - we use compile-time |
| * static initialisation because per-cpu memory isn't |
| * ready yet and because the memory allocators are not |
| * initialised either. |
| */ |
| boot_done = 1; |
| base = &boot_tvec_bases; |
| } |
| tvec_base_done[cpu] = 1; |
| } else { |
| base = per_cpu(tvec_bases, 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); |
| 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 __cpuinit 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 __cpuinitdata timers_nb = { |
| .notifier_call = timer_cpu_notify, |
| }; |
| |
| |
| void __init init_timers(void) |
| { |
| int err = timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE, |
| (void *)(long)smp_processor_id()); |
| |
| BUG_ON(err == NOTIFY_BAD); |
| register_cpu_notifier(&timers_nb); |
| open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL); |
| } |
| |
| #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 |
| |
| 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 */ |
| BUG_ON(ti->frequency == 0 || ti->mask == 0); |
| |
| 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); |