tvec_base_t boot_tvec_bases;
EXPORT_SYMBOL(boot_tvec_bases);
-static DEFINE_PER_CPU(tvec_base_t *, tvec_bases) = { &boot_tvec_bases };
+static DEFINE_PER_CPU(tvec_base_t *, tvec_bases) = &boot_tvec_bases;
static inline void set_running_timer(tvec_base_t *base,
struct timer_list *timer)
list_add_tail(&timer->entry, vec);
}
-/***
+/**
* init_timer - initialize a timer.
* @timer: the timer to be initialized
*
*/
static tvec_base_t *lock_timer_base(struct timer_list *timer,
unsigned long *flags)
+ __acquires(timer->base->lock)
{
tvec_base_t *base;
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
}
-/***
+/**
* 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)
EXPORT_SYMBOL(mod_timer);
-/***
+/**
* del_timer - deactive a timer.
* @timer: the timer to be deactivated
*
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.
*
return ret;
}
-/***
+/**
* del_timer_sync - deactivate a timer and wait for the handler to finish.
* @timer: the timer to be deactivated
*
int ret = try_to_del_timer_sync(timer);
if (ret >= 0)
return ret;
+ cpu_relax();
}
}
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.
*/
-#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;
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);
}
-/*
+static int timekeeping_suspended;
+/**
* timekeeping_resume - Resumes the generic timekeeping subsystem.
* @dev: unused
*
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"),
};
device_initcall(timekeeping_init_device);
/*
- * If the error is already larger, we look ahead another tick,
+ * If the error is already larger, we look ahead even further
* to compensate for late or lost adjustments.
*/
-static __always_inline int clocksource_bigadjust(int sign, s64 error, s64 *interval, s64 *offset)
+static __always_inline int clocksource_bigadjust(s64 error, s64 *interval, s64 *offset)
{
- int adj;
+ s64 tick_error, i;
+ u32 look_ahead, adj;
+ s32 error2, mult;
/*
- * As soon as the machine is synchronized to the external time
- * source this should be the common case.
+ * 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).
*/
- error >>= 2;
- if (likely(sign > 0 ? error <= *interval : error >= *interval))
- return sign;
+ error2 = clock->error >> (TICK_LENGTH_SHIFT + 22 - 2 * SHIFT_HZ);
+ error2 = abs(error2);
+ for (look_ahead = 0; error2 > 0; look_ahead++)
+ error2 >>= 2;
/*
- * An extra look ahead dampens the effect of the current error,
- * which can grow quite large with continously late updates, as
- * it would dominate the adjustment value and can lead to
- * oscillation.
+ * Now calculate the error in (1 << look_ahead) ticks, but first
+ * remove the single look ahead already included in the error.
*/
- error += current_tick_length() >> (TICK_LENGTH_SHIFT - clock->shift + 1);
- error -= clock->xtime_interval >> 1;
-
- adj = 0;
- while (1) {
- error >>= 1;
- if (sign > 0 ? error <= *interval : error >= *interval)
- break;
- adj++;
+ 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;
}
-
- /*
- * Add the current adjustments to the error and take the offset
- * into account, the latter can cause the error to be hardly
- * reduced at the next tick. Check the error again if there's
- * room for another adjustment, thus further reducing the error
- * which otherwise had to be corrected at the next update.
- */
- error = (error << 1) - *interval + *offset;
- if (sign > 0 ? error > *interval : error < *interval)
- adj++;
+ for (adj = 0; error > i; adj++)
+ error >>= 1;
*interval <<= adj;
*offset <<= adj;
- return sign << adj;
+ return mult << adj;
}
/*
error = clock->error >> (TICK_LENGTH_SHIFT - clock->shift - 1);
if (error > interval) {
- adj = clocksource_bigadjust(1, error, &interval, &offset);
+ error >>= 2;
+ if (likely(error <= interval))
+ adj = 1;
+ else
+ adj = clocksource_bigadjust(error, &interval, &offset);
} else if (error < -interval) {
- interval = -interval;
- offset = -offset;
- adj = clocksource_bigadjust(-1, error, &interval, &offset);
+ error >>= 2;
+ if (likely(error >= -interval)) {
+ adj = -1;
+ interval = -interval;
+ offset = -offset;
+ } else
+ adj = clocksource_bigadjust(error, &interval, &offset);
} else
return;
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.
{
cycle_t offset;
- clock->xtime_nsec += (s64)xtime.tv_nsec << clock->shift;
+ /* 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.
clocksource_adjust(clock, offset);
/* store full nanoseconds into xtime */
- xtime.tv_nsec = clock->xtime_nsec >> clock->shift;
+ 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 */
unsigned long active_tasks; /* fixed-point */
static int count = LOAD_FREQ;
- count -= ticks;
- if (count < 0) {
- count += LOAD_FREQ;
- active_tasks = count_active_tasks();
+ 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);
* Called by the timer interrupt. xtime_lock must already be taken
* by the timer IRQ!
*/
-static inline void update_times(void)
+static inline void update_times(unsigned long ticks)
{
- unsigned long ticks;
-
- ticks = jiffies - wall_jiffies;
wall_jiffies += ticks;
update_wall_time();
calc_load(ticks);
* jiffies is defined in the linker script...
*/
-void do_timer(struct pt_regs *regs)
+void do_timer(unsigned long ticks)
{
- jiffies_64++;
- /* prevent loading jiffies before storing new jiffies_64 value. */
- barrier();
- update_times();
+ jiffies_64 += ticks;
+ update_times(ticks);
}
#ifdef __ARCH_WANT_SYS_ALARM
}
/*
- * 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.
+ * 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;
- 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;
+ rcu_read_lock();
+ pid = rcu_dereference(current->real_parent)->tgid;
+ rcu_read_unlock();
- /*
- * 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;
}
return current->pid;
}
-/*
+/**
* sys_sysinfo - fill in sysinfo struct
+ * @info: pointer to buffer to fill
*/
asmlinkage long sys_sysinfo(struct sysinfo __user *info)
{
}
#endif /* CONFIG_HOTPLUG_CPU */
-static int __devinit timer_cpu_notify(struct notifier_block *self,
+static int __cpuinit timer_cpu_notify(struct notifier_block *self,
unsigned long action, void *hcpu)
{
long cpu = (long)hcpu;
return NOTIFY_OK;
}
-static struct notifier_block __devinitdata timers_nb = {
+static struct notifier_block __cpuinitdata timers_nb = {
.notifier_call = timer_cpu_notify,
};
void __init init_timers(void)
{
- timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE,
+ 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);
}
projects / linux-2.6-omap-h63xx.git / blobdiff