#include <linux/delay.h>
#include <linux/tick.h>
#include <linux/kallsyms.h>
-#include <linux/perf_counter.h>
+#include <linux/perf_event.h>
#include <linux/sched.h>
+#include <linux/slab.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
#include <asm/timex.h>
#include <asm/io.h>
+#define CREATE_TRACE_POINTS
+#include <trace/events/timer.h>
+
u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES;
EXPORT_SYMBOL(jiffies_64);
spinlock_t lock;
struct timer_list *running_timer;
unsigned long timer_jiffies;
+ unsigned long next_timer;
struct tvec_root tv1;
struct tvec tv2;
struct tvec tv3;
}
EXPORT_SYMBOL_GPL(round_jiffies_up_relative);
+/**
+ * set_timer_slack - set the allowed slack for a timer
+ * @slack_hz: the amount of time (in jiffies) allowed for rounding
+ *
+ * Set the amount of time, in jiffies, that a certain timer has
+ * in terms of slack. By setting this value, the timer subsystem
+ * will schedule the actual timer somewhere between
+ * the time mod_timer() asks for, and that time plus the slack.
+ *
+ * By setting the slack to -1, a percentage of the delay is used
+ * instead.
+ */
+void set_timer_slack(struct timer_list *timer, int slack_hz)
+{
+ timer->slack = slack_hz;
+}
+EXPORT_SYMBOL_GPL(set_timer_slack);
+
static inline void set_running_timer(struct tvec_base *base,
struct timer_list *timer)
static inline void debug_timer_deactivate(struct timer_list *timer) { }
#endif
+static inline void debug_init(struct timer_list *timer)
+{
+ debug_timer_init(timer);
+ trace_timer_init(timer);
+}
+
+static inline void
+debug_activate(struct timer_list *timer, unsigned long expires)
+{
+ debug_timer_activate(timer);
+ trace_timer_start(timer, expires);
+}
+
+static inline void debug_deactivate(struct timer_list *timer)
+{
+ debug_timer_deactivate(timer);
+ trace_timer_cancel(timer);
+}
+
static void __init_timer(struct timer_list *timer,
const char *name,
struct lock_class_key *key)
{
timer->entry.next = NULL;
timer->base = __raw_get_cpu_var(tvec_bases);
+ timer->slack = -1;
#ifdef CONFIG_TIMER_STATS
timer->start_site = NULL;
timer->start_pid = -1;
const char *name,
struct lock_class_key *key)
{
- debug_timer_init(timer);
+ debug_init(timer);
__init_timer(timer, name, key);
}
EXPORT_SYMBOL(init_timer_key);
{
struct list_head *entry = &timer->entry;
- debug_timer_deactivate(timer);
+ debug_deactivate(timer);
__list_del(entry->prev, entry->next);
if (clear_pending)
if (timer_pending(timer)) {
detach_timer(timer, 0);
+ if (timer->expires == base->next_timer &&
+ !tbase_get_deferrable(timer->base))
+ base->next_timer = base->timer_jiffies;
ret = 1;
} else {
if (pending_only)
goto out_unlock;
}
- debug_timer_activate(timer);
-
- new_base = __get_cpu_var(tvec_bases);
+ debug_activate(timer, expires);
cpu = smp_processor_id();
}
timer->expires = expires;
+ if (time_before(timer->expires, base->next_timer) &&
+ !tbase_get_deferrable(timer->base))
+ base->next_timer = timer->expires;
internal_add_timer(base, timer);
out_unlock:
}
EXPORT_SYMBOL(mod_timer_pending);
+/*
+ * Decide where to put the timer while taking the slack into account
+ *
+ * Algorithm:
+ * 1) calculate the maximum (absolute) time
+ * 2) calculate the highest bit where the expires and new max are different
+ * 3) use this bit to make a mask
+ * 4) use the bitmask to round down the maximum time, so that all last
+ * bits are zeros
+ */
+static inline
+unsigned long apply_slack(struct timer_list *timer, unsigned long expires)
+{
+ unsigned long expires_limit, mask;
+ int bit;
+
+ expires_limit = expires + timer->slack;
+
+ if (timer->slack < 0) /* auto slack: use 0.4% */
+ expires_limit = expires + (expires - jiffies)/256;
+
+ mask = expires ^ expires_limit;
+
+ if (mask == 0)
+ return expires;
+
+ bit = find_last_bit(&mask, BITS_PER_LONG);
+
+ mask = (1 << bit) - 1;
+
+ expires_limit = expires_limit & ~(mask);
+
+ return expires_limit;
+}
+
/**
* mod_timer - modify a timer's timeout
* @timer: the timer to be modified
* networking code - if the timer is re-modified
* to be the same thing then just return:
*/
- if (timer->expires == expires && timer_pending(timer))
+ if (timer_pending(timer) && timer->expires == expires)
return 1;
+ expires = apply_slack(timer, expires);
+
return __mod_timer(timer, expires, false, TIMER_NOT_PINNED);
}
EXPORT_SYMBOL(mod_timer);
BUG_ON(timer_pending(timer) || !timer->function);
spin_lock_irqsave(&base->lock, flags);
timer_set_base(timer, base);
- debug_timer_activate(timer);
+ debug_activate(timer, timer->expires);
+ if (time_before(timer->expires, base->next_timer) &&
+ !tbase_get_deferrable(timer->base))
+ base->next_timer = timer->expires;
internal_add_timer(base, timer);
/*
* Check whether the other CPU is idle and needs to be
base = lock_timer_base(timer, &flags);
if (timer_pending(timer)) {
detach_timer(timer, 1);
+ if (timer->expires == base->next_timer &&
+ !tbase_get_deferrable(timer->base))
+ base->next_timer = base->timer_jiffies;
ret = 1;
}
spin_unlock_irqrestore(&base->lock, flags);
if (base->running_timer == timer)
goto out;
+ timer_stats_timer_clear_start_info(timer);
ret = 0;
if (timer_pending(timer)) {
detach_timer(timer, 1);
+ if (timer->expires == base->next_timer &&
+ !tbase_get_deferrable(timer->base))
+ base->next_timer = base->timer_jiffies;
ret = 1;
}
out:
return index;
}
+static void call_timer_fn(struct timer_list *timer, void (*fn)(unsigned long),
+ unsigned long data)
+{
+ int preempt_count = preempt_count();
+
+#ifdef CONFIG_LOCKDEP
+ /*
+ * It is permissible to free the timer from inside the
+ * function that is called from it, this we need to take into
+ * account for lockdep too. To avoid bogus "held lock freed"
+ * warnings as well as problems when looking into
+ * timer->lockdep_map, make a copy and use that here.
+ */
+ struct lockdep_map lockdep_map = timer->lockdep_map;
+#endif
+ /*
+ * Couple the lock chain with the lock chain at
+ * del_timer_sync() by acquiring the lock_map around the fn()
+ * call here and in del_timer_sync().
+ */
+ lock_map_acquire(&lockdep_map);
+
+ trace_timer_expire_entry(timer);
+ fn(data);
+ trace_timer_expire_exit(timer);
+
+ lock_map_release(&lockdep_map);
+
+ if (preempt_count != preempt_count()) {
+ WARN_ONCE(1, "timer: %pF preempt leak: %08x -> %08x\n",
+ fn, preempt_count, preempt_count());
+ /*
+ * Restore the preempt count. That gives us a decent
+ * chance to survive and extract information. If the
+ * callback kept a lock held, bad luck, but not worse
+ * than the BUG() we had.
+ */
+ preempt_count() = preempt_count;
+ }
+}
+
#define INDEX(N) ((base->timer_jiffies >> (TVR_BITS + (N) * TVN_BITS)) & TVN_MASK)
/**
detach_timer(timer, 1);
spin_unlock_irq(&base->lock);
- {
- int preempt_count = preempt_count();
-
-#ifdef CONFIG_LOCKDEP
- /*
- * It is permissible to free the timer from
- * inside the function that is called from
- * it, this we need to take into account for
- * lockdep too. To avoid bogus "held lock
- * freed" warnings as well as problems when
- * looking into timer->lockdep_map, make a
- * copy and use that here.
- */
- struct lockdep_map lockdep_map =
- timer->lockdep_map;
-#endif
- /*
- * Couple the lock chain with the lock chain at
- * del_timer_sync() by acquiring the lock_map
- * around the fn() call here and in
- * del_timer_sync().
- */
- lock_map_acquire(&lockdep_map);
-
- fn(data);
-
- lock_map_release(&lockdep_map);
-
- if (preempt_count != preempt_count()) {
- printk(KERN_ERR "huh, entered %p "
- "with preempt_count %08x, exited"
- " with %08x?\n",
- fn, preempt_count,
- preempt_count());
- BUG();
- }
- }
+ call_timer_fn(timer, fn, data);
spin_lock_irq(&base->lock);
}
}
#ifdef CONFIG_NO_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.
+ * is used on S/390 to stop all activity when a CPU is idle.
+ * This function needs to be called with interrupts disabled.
*/
static unsigned long __next_timer_interrupt(struct tvec_base *base)
{
unsigned long expires;
spin_lock(&base->lock);
- expires = __next_timer_interrupt(base);
+ if (time_before_eq(base->next_timer, base->timer_jiffies))
+ base->next_timer = __next_timer_interrupt(base);
+ expires = base->next_timer;
spin_unlock(&base->lock);
if (time_before_eq(expires, now))
/* Note: this timer irq context must be accounted for as well. */
account_process_tick(p, user_tick);
run_local_timers();
- if (rcu_pending(cpu))
- rcu_check_callbacks(cpu, user_tick);
+ rcu_check_callbacks(cpu, user_tick);
printk_tick();
+ perf_event_do_pending();
scheduler_tick();
run_posix_cpu_timers(p);
}
{
struct tvec_base *base = __get_cpu_var(tvec_bases);
- perf_counter_do_pending();
-
hrtimer_run_pending();
if (time_after_eq(jiffies, base->timer_jiffies))
INIT_LIST_HEAD(base->tv1.vec + j);
base->timer_jiffies = jiffies;
+ base->next_timer = base->timer_jiffies;
return 0;
}
timer = list_first_entry(head, struct timer_list, entry);
detach_timer(timer, 0);
timer_set_base(timer, new_base);
+ if (time_before(timer->expires, new_base->next_timer) &&
+ !tbase_get_deferrable(timer->base))
+ new_base->next_timer = timer->expires;
internal_add_timer(new_base, timer);
}
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff