}
EXPORT_SYMBOL_GPL(get_cpu_iowait_time_us);
-static void tick_nohz_stop_sched_tick(struct tick_sched *ts)
+static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts,
+ ktime_t now, int cpu)
{
unsigned long seq, last_jiffies, next_jiffies, delta_jiffies;
+ ktime_t last_update, expires, ret = { .tv64 = 0 };
unsigned long rcu_delta_jiffies;
- ktime_t last_update, expires, now;
struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev;
u64 time_delta;
- int cpu;
-
- cpu = smp_processor_id();
- ts = &per_cpu(tick_cpu_sched, cpu);
-
- now = tick_nohz_start_idle(cpu, ts);
-
- /*
- * If this cpu is offline and it is the one which updates
- * jiffies, then give up the assignment and let it be taken by
- * the cpu which runs the tick timer next. If we don't drop
- * this here the jiffies might be stale and do_timer() never
- * invoked.
- */
- if (unlikely(!cpu_online(cpu))) {
- if (cpu == tick_do_timer_cpu)
- tick_do_timer_cpu = TICK_DO_TIMER_NONE;
- }
-
- if (unlikely(ts->nohz_mode == NOHZ_MODE_INACTIVE))
- return;
- if (need_resched())
- return;
-
- if (unlikely(local_softirq_pending() && cpu_online(cpu))) {
- static int ratelimit;
-
- if (ratelimit < 10) {
- printk(KERN_ERR "NOHZ: local_softirq_pending %02x\n",
- (unsigned int) local_softirq_pending());
- ratelimit++;
- }
- return;
- }
-
- ts->idle_calls++;
/* Read jiffies and the time when jiffies were updated last */
do {
seq = read_seqbegin(&xtime_lock);
if (ts->tick_stopped && ktime_equal(expires, dev->next_event))
goto out;
+ ret = expires;
+
/*
* nohz_stop_sched_tick can be called several times before
* the nohz_restart_sched_tick is called. This happens when
select_nohz_load_balancer(1);
calc_load_enter_idle();
- ts->idle_tick = hrtimer_get_expires(&ts->sched_timer);
+ ts->last_tick = hrtimer_get_expires(&ts->sched_timer);
ts->tick_stopped = 1;
- ts->idle_jiffies = last_jiffies;
}
- ts->idle_sleeps++;
-
- /* Mark expires */
- ts->idle_expires = expires;
-
/*
* If the expiration time == KTIME_MAX, then
* in this case we simply stop the tick timer.
ts->next_jiffies = next_jiffies;
ts->last_jiffies = last_jiffies;
ts->sleep_length = ktime_sub(dev->next_event, now);
+
+ return ret;
+}
+
+static bool can_stop_idle_tick(int cpu, struct tick_sched *ts)
+{
+ /*
+ * If this cpu is offline and it is the one which updates
+ * jiffies, then give up the assignment and let it be taken by
+ * the cpu which runs the tick timer next. If we don't drop
+ * this here the jiffies might be stale and do_timer() never
+ * invoked.
+ */
+ if (unlikely(!cpu_online(cpu))) {
+ if (cpu == tick_do_timer_cpu)
+ tick_do_timer_cpu = TICK_DO_TIMER_NONE;
+ }
+
+ if (unlikely(ts->nohz_mode == NOHZ_MODE_INACTIVE))
+ return false;
+
+ if (need_resched())
+ return false;
+
+ if (unlikely(local_softirq_pending() && cpu_online(cpu))) {
+ static int ratelimit;
+
+ if (ratelimit < 10) {
+ printk(KERN_ERR "NOHZ: local_softirq_pending %02x\n",
+ (unsigned int) local_softirq_pending());
+ ratelimit++;
+ }
+ return false;
+ }
+
+ return true;
+}
+
+static void __tick_nohz_idle_enter(struct tick_sched *ts)
+{
+ ktime_t now, expires;
+ int cpu = smp_processor_id();
+
+ now = tick_nohz_start_idle(cpu, ts);
+
+ if (can_stop_idle_tick(cpu, ts)) {
+ int was_stopped = ts->tick_stopped;
+
+ ts->idle_calls++;
+
+ expires = tick_nohz_stop_sched_tick(ts, now, cpu);
+ if (expires.tv64 > 0LL) {
+ ts->idle_sleeps++;
+ ts->idle_expires = expires;
+ }
+
+ if (!was_stopped && ts->tick_stopped)
+ ts->idle_jiffies = ts->last_jiffies;
+ }
}
/**
* update of the idle time accounting in tick_nohz_start_idle().
*/
ts->inidle = 1;
- tick_nohz_stop_sched_tick(ts);
+ __tick_nohz_idle_enter(ts);
local_irq_enable();
}
if (!ts->inidle)
return;
- tick_nohz_stop_sched_tick(ts);
+ __tick_nohz_idle_enter(ts);
}
/**
static void tick_nohz_restart(struct tick_sched *ts, ktime_t now)
{
hrtimer_cancel(&ts->sched_timer);
- hrtimer_set_expires(&ts->sched_timer, ts->idle_tick);
+ hrtimer_set_expires(&ts->sched_timer, ts->last_tick);
while (1) {
/* Forward the time to expire in the future */
}
}
+static void tick_nohz_restart_sched_tick(struct tick_sched *ts, ktime_t now)
+{
+ /* Update jiffies first */
+ select_nohz_load_balancer(0);
+ tick_do_update_jiffies64(now);
+ update_cpu_load_nohz();
+
+ touch_softlockup_watchdog();
+ /*
+ * Cancel the scheduled timer and restore the tick
+ */
+ ts->tick_stopped = 0;
+ ts->idle_exittime = now;
+
+ tick_nohz_restart(ts, now);
+}
+
+static void tick_nohz_account_idle_ticks(struct tick_sched *ts)
+{
+#ifndef CONFIG_VIRT_CPU_ACCOUNTING
+ unsigned long ticks;
+ /*
+ * We stopped the tick in idle. Update process times would miss the
+ * time we slept as update_process_times does only a 1 tick
+ * accounting. Enforce that this is accounted to idle !
+ */
+ ticks = jiffies - ts->idle_jiffies;
+ /*
+ * We might be one off. Do not randomly account a huge number of ticks!
+ */
+ if (ticks && ticks < LONG_MAX)
+ account_idle_ticks(ticks);
+#endif
+}
+
/**
* tick_nohz_idle_exit - restart the idle tick from the idle task
*
{
int cpu = smp_processor_id();
struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
-#ifndef CONFIG_VIRT_CPU_ACCOUNTING
- unsigned long ticks;
-#endif
ktime_t now;
local_irq_disable();
if (ts->idle_active)
tick_nohz_stop_idle(cpu, now);
- if (!ts->tick_stopped) {
- local_irq_enable();
- return;
+ if (ts->tick_stopped) {
+ tick_nohz_restart_sched_tick(ts, now);
+ tick_nohz_account_idle_ticks(ts);
}
- /* Update jiffies first */
- select_nohz_load_balancer(0);
- tick_do_update_jiffies64(now);
- update_cpu_load_nohz();
-
-#ifndef CONFIG_VIRT_CPU_ACCOUNTING
- /*
- * We stopped the tick in idle. Update process times would miss the
- * time we slept as update_process_times does only a 1 tick
- * accounting. Enforce that this is accounted to idle !
- */
- ticks = jiffies - ts->idle_jiffies;
- /*
- * We might be one off. Do not randomly account a huge number of ticks!
- */
- if (ticks && ticks < LONG_MAX)
- account_idle_ticks(ticks);
-#endif
-
- calc_load_exit_idle();
- touch_softlockup_watchdog();
- /*
- * Cancel the scheduled timer and restore the tick
- */
- ts->tick_stopped = 0;
- ts->idle_exittime = now;
-
- tick_nohz_restart(ts, now);
-
local_irq_enable();
}
*/
if (ts->tick_stopped) {
touch_softlockup_watchdog();
- ts->idle_jiffies++;
+ if (idle_cpu(cpu))
+ ts->idle_jiffies++;
}
update_process_times(user_mode(regs));
profile_tick(CPU_PROFILING);
projects / ~andy / linux / blobdiff