*
* Started by: Thomas Gleixner and Ingo Molnar
*
- * For licencing details see kernel-base/COPYING
+ * Distribute under GPLv2.
*/
#include <linux/cpu.h>
#include <linux/err.h>
unsigned long ticks = 0;
ktime_t delta;
+ /*
+ * Do a quick check without holding xtime_lock:
+ */
+ delta = ktime_sub(now, last_jiffies_update);
+ if (delta.tv64 < tick_period.tv64)
+ return;
+
/* Reevalute with xtime_lock held */
write_seqlock(&xtime_lock);
if (!ts->tick_stopped)
return;
- touch_softlockup_watchdog();
-
cpu_clear(cpu, nohz_cpu_mask);
now = ktime_get();
+ ts->idle_waketime = now;
local_irq_save(flags);
tick_do_update_jiffies64(now);
local_irq_restore(flags);
+
+ touch_softlockup_watchdog();
+}
+
+void tick_nohz_stop_idle(int cpu)
+{
+ struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
+
+ if (ts->idle_active) {
+ ktime_t now, delta;
+ now = ktime_get();
+ delta = ktime_sub(now, ts->idle_entrytime);
+ ts->idle_lastupdate = now;
+ ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
+ ts->idle_active = 0;
+
+ sched_clock_idle_wakeup_event(0);
+ }
+}
+
+static ktime_t tick_nohz_start_idle(struct tick_sched *ts)
+{
+ ktime_t now, delta;
+
+ now = ktime_get();
+ if (ts->idle_active) {
+ delta = ktime_sub(now, ts->idle_entrytime);
+ ts->idle_lastupdate = now;
+ ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
+ }
+ ts->idle_entrytime = now;
+ ts->idle_active = 1;
+ sched_clock_idle_sleep_event();
+ return now;
+}
+
+u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time)
+{
+ struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
+
+ *last_update_time = ktime_to_us(ts->idle_lastupdate);
+ return ktime_to_us(ts->idle_sleeptime);
}
/**
* Called either from the idle loop or from irq_exit() when an idle period was
* just interrupted by an interrupt which did not cause a reschedule.
*/
-void tick_nohz_stop_sched_tick(void)
+void tick_nohz_stop_sched_tick(int inidle)
{
unsigned long seq, last_jiffies, next_jiffies, delta_jiffies, flags;
- unsigned long rt_jiffies;
struct tick_sched *ts;
- ktime_t last_update, expires, now, delta;
+ ktime_t last_update, expires, now;
struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev;
int cpu;
cpu = smp_processor_id();
ts = &per_cpu(tick_cpu_sched, cpu);
+ now = tick_nohz_start_idle(ts);
/*
* If this cpu is offline and it is the one which updates
if (unlikely(ts->nohz_mode == NOHZ_MODE_INACTIVE))
goto end;
+ if (!inidle && !ts->inidle)
+ goto end;
+
+ ts->inidle = 1;
+
if (need_resched())
goto end;
- cpu = smp_processor_id();
if (unlikely(local_softirq_pending())) {
static int ratelimit;
local_softirq_pending());
ratelimit++;
}
+ goto end;
}
- now = ktime_get();
- /*
- * When called from irq_exit we need to account the idle sleep time
- * correctly.
- */
- if (ts->tick_stopped) {
- delta = ktime_sub(now, ts->idle_entrytime);
- ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
- }
-
- ts->idle_entrytime = now;
ts->idle_calls++;
-
/* Read jiffies and the time when jiffies were updated last */
do {
seq = read_seqbegin(&xtime_lock);
next_jiffies = get_next_timer_interrupt(last_jiffies);
delta_jiffies = next_jiffies - last_jiffies;
- rt_jiffies = rt_needs_cpu(cpu);
- if (rt_jiffies && rt_jiffies < delta_jiffies)
- delta_jiffies = rt_jiffies;
-
if (rcu_needs_cpu(cpu))
delta_jiffies = 1;
/*
ts->idle_tick = ts->sched_timer.expires;
ts->tick_stopped = 1;
ts->idle_jiffies = last_jiffies;
+ rcu_enter_nohz();
}
/*
/* Check, if the timer was already in the past */
if (hrtimer_active(&ts->sched_timer))
goto out;
- } else if(!tick_program_event(expires, 0))
+ } else if (!tick_program_event(expires, 0))
goto out;
/*
* We are past the event already. So we crossed a
int cpu = smp_processor_id();
struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
unsigned long ticks;
- ktime_t now, delta;
+ ktime_t now;
- if (!ts->tick_stopped)
+ local_irq_disable();
+ tick_nohz_stop_idle(cpu);
+
+ if (!ts->inidle || !ts->tick_stopped) {
+ ts->inidle = 0;
+ local_irq_enable();
return;
+ }
- /* Update jiffies first */
- now = ktime_get();
+ ts->inidle = 0;
- local_irq_disable();
+ rcu_exit_nohz();
+
+ /* Update jiffies first */
select_nohz_load_balancer(0);
+ now = ktime_get();
tick_do_update_jiffies64(now);
cpu_clear(cpu, nohz_cpu_mask);
- /* Account the idle time */
- delta = ktime_sub(now, ts->idle_entrytime);
- ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
-
/*
* We stopped the tick in idle. Update process times would miss the
* time we slept as update_process_times does only a 1 tick
sub_preempt_count(HARDIRQ_OFFSET);
}
+ touch_softlockup_watchdog();
/*
* Cancel the scheduled timer and restore the tick
*/
ts->tick_stopped = 0;
+ ts->idle_exittime = now;
hrtimer_cancel(&ts->sched_timer);
ts->sched_timer.expires = ts->idle_tick;
*/
#ifdef CONFIG_HIGH_RES_TIMERS
/*
- * We rearm the timer until we get disabled by the idle code
+ * We rearm the timer until we get disabled by the idle code.
* Called with interrupts disabled and timer->base->cpu_base->lock held.
*/
static enum hrtimer_restart tick_sched_timer(struct hrtimer *timer)
ts->nohz_mode = NOHZ_MODE_HIGHRES;
#endif
}
+#endif /* HIGH_RES_TIMERS */
+#if defined CONFIG_NO_HZ || defined CONFIG_HIGH_RES_TIMERS
void tick_cancel_sched_timer(int cpu)
{
struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
+# ifdef CONFIG_HIGH_RES_TIMERS
if (ts->sched_timer.base)
hrtimer_cancel(&ts->sched_timer);
- ts->tick_stopped = 0;
+# endif
+
ts->nohz_mode = NOHZ_MODE_INACTIVE;
}
-#endif /* HIGH_RES_TIMERS */
+#endif
/**
* Async notification about clocksource changes
if (ts->nohz_mode != NOHZ_MODE_INACTIVE)
return 0;
- if (!timekeeping_is_continuous() || !tick_is_oneshot_available())
+ if (!timekeeping_valid_for_hres() || !tick_is_oneshot_available())
return 0;
if (!allow_nohz)
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff