Exemple #1
0
Fichier : setup.c Projet : kx/linux
static void iseries_dedicated_idle(void)
{
	set_thread_flag(TIF_POLLING_NRFLAG);

	while (1) {
		tick_nohz_idle_enter();
		rcu_idle_enter();
		if (!need_resched()) {
			while (!need_resched()) {
				ppc64_runlatch_off();
				HMT_low();

				if (hvlpevent_is_pending()) {
					HMT_medium();
					ppc64_runlatch_on();
					process_iSeries_events();
				}
			}

			HMT_medium();
		}

		ppc64_runlatch_on();
		rcu_idle_exit();
		tick_nohz_idle_exit();
		schedule_preempt_disabled();
	}
}
Exemple #2
0
void cpu_idle(void)
{
	set_thread_flag(TIF_POLLING_NRFLAG);

	/* endless idle loop with no priority at all */
	while (1) {
		tick_nohz_idle_enter();
		rcu_idle_enter();

		while (!need_resched()) {
			check_pgt_cache();
			rmb();

			clear_thread_flag(TIF_POLLING_NRFLAG);

			local_irq_disable();
			/* Don't trace irqs off for idle */
			stop_critical_timings();
			if (!need_resched() && powersave != NULL)
				powersave();
			start_critical_timings();
			local_irq_enable();
			set_thread_flag(TIF_POLLING_NRFLAG);
		}

		rcu_idle_exit();
		tick_nohz_idle_exit();
		preempt_enable_no_resched();
		schedule();
		preempt_disable();
	}
}
Exemple #3
0
Fichier : setup.c Projet : kx/linux
static void iseries_shared_idle(void)
{
	while (1) {
		tick_nohz_idle_enter();
		rcu_idle_enter();
		while (!need_resched() && !hvlpevent_is_pending()) {
			local_irq_disable();
			ppc64_runlatch_off();

			/* Recheck with irqs off */
			if (!need_resched() && !hvlpevent_is_pending())
				yield_shared_processor();

			HMT_medium();
			local_irq_enable();
		}

		ppc64_runlatch_on();
		rcu_idle_exit();
		tick_nohz_idle_exit();

		if (hvlpevent_is_pending())
			process_iSeries_events();

		schedule_preempt_disabled();
	}
}
Exemple #4
0
/*
 * The body of the idle task.
 */
void cpu_idle(void)
{
	if (ppc_md.idle_loop)
		ppc_md.idle_loop();	/* doesn't return */

	set_thread_flag(TIF_POLLING_NRFLAG);
	while (1) {
		tick_nohz_idle_enter();
		rcu_idle_enter();

		while (!need_resched() && !cpu_should_die()) {
			ppc64_runlatch_off();

			if (ppc_md.power_save) {
				clear_thread_flag(TIF_POLLING_NRFLAG);
				/*
				 * smp_mb is so clearing of TIF_POLLING_NRFLAG
				 * is ordered w.r.t. need_resched() test.
				 */
				smp_mb();
				local_irq_disable();

				/* Don't trace irqs off for idle */
				stop_critical_timings();

				/* check again after disabling irqs */
				if (!need_resched() && !cpu_should_die())
					ppc_md.power_save();

				start_critical_timings();

				/* Some power_save functions return with
				 * interrupts enabled, some don't.
				 */
				if (irqs_disabled())
					local_irq_enable();
				set_thread_flag(TIF_POLLING_NRFLAG);

			} else {
				/*
				 * Go into low thread priority and possibly
				 * low power mode.
				 */
				HMT_low();
				HMT_very_low();
			}
		}

		HMT_medium();
		ppc64_runlatch_on();
		rcu_idle_exit();
		tick_nohz_idle_exit();
		if (cpu_should_die()) {
			sched_preempt_enable_no_resched();
			cpu_die();
		}
		schedule_preempt_disabled();
	}
}
Exemple #5
0
/*
 * Generic idle loop implementation
 */
static void cpu_idle_loop(void)
{
	while (1) {
		tick_nohz_idle_enter();

		while (!need_resched()) {
			check_pgt_cache();
			rmb();

			if (cpu_is_offline(smp_processor_id()))
				arch_cpu_idle_dead();

			local_irq_disable();
			arch_cpu_idle_enter();

			/*
			 * In poll mode we reenable interrupts and spin.
			 *
			 * Also if we detected in the wakeup from idle
			 * path that the tick broadcast device expired
			 * for us, we don't want to go deep idle as we
			 * know that the IPI is going to arrive right
			 * away
			 */
			if (cpu_idle_force_poll || tick_check_broadcast_expired()) {
				cpu_idle_poll();
			} else {
				if (!current_clr_polling_and_test()) {
					stop_critical_timings();
					rcu_idle_enter();
					arch_cpu_idle();
					WARN_ON_ONCE(irqs_disabled());
					rcu_idle_exit();
					start_critical_timings();
				} else {
					local_irq_enable();
				}
				__current_set_polling();
			}
			arch_cpu_idle_exit();
		}

		/*
		 * Since we fell out of the loop above, we know
		 * TIF_NEED_RESCHED must be set, propagate it into
		 * PREEMPT_NEED_RESCHED.
		 *
		 * This is required because for polling idle loops we will
		 * not have had an IPI to fold the state for us.
		 */
		preempt_set_need_resched();
		tick_nohz_idle_exit();
		schedule_preempt_disabled();
	}
}
Exemple #6
0
static inline int cpu_idle_poll(void)
{
	rcu_idle_enter();
	trace_cpu_idle_rcuidle(0, smp_processor_id());
	local_irq_enable();
	while (!tif_need_resched())
		cpu_relax();
	trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id());
	rcu_idle_exit();
	return 1;
}
static inline int cpu_idle_poll(void)
{
	rcu_idle_enter();
	trace_cpu_idle_rcuidle(0, smp_processor_id());
	local_irq_enable();
	while (!tif_need_resched() &&
		(cpu_idle_force_poll || tick_check_broadcast_expired() ||
		__get_cpu_var(idle_force_poll)))
		cpu_relax();
	trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id());
	rcu_idle_exit();
	return 1;
}
Exemple #8
0
void cpu_idle(void)
{
  	local_irq_enable();

	/* endless idle loop with no priority at all */
	while (1) {
		rcu_idle_enter();
		while (!need_resched())
			platform_idle();
		rcu_idle_exit();
		schedule_preempt_disabled();
	}
}
Exemple #9
0
static noinline int __cpuidle cpu_idle_poll(void)
{
	rcu_idle_enter();
	trace_cpu_idle_rcuidle(0, smp_processor_id());
	local_irq_enable();
	stop_critical_timings();
	while (!tif_need_resched() &&
		(cpu_idle_force_poll || tick_check_broadcast_expired()))
		cpu_relax();
	start_critical_timings();
	trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id());
	rcu_idle_exit();
	return 1;
}
Exemple #10
0
/*
 * The idle thread. There's no useful work to be
 * done, so just try to conserve power and have a
 * low exit latency (ie sit in a loop waiting for
 * somebody to say that they'd like to reschedule)
 */
void cpu_idle(void)
{
	set_thread_flag(TIF_POLLING_NRFLAG);

	/* endless idle loop with no priority at all */
	while (1) {
		rcu_idle_enter();
		while (!need_resched())
			barrier();
		rcu_idle_exit();
		schedule_preempt_disabled();
		check_pgt_cache();
	}
}
void cpu_idle(void)
{
	if (ppc_md.idle_loop)
		ppc_md.idle_loop();	

	set_thread_flag(TIF_POLLING_NRFLAG);
	while (1) {
		tick_nohz_idle_enter();
		rcu_idle_enter();

		while (!need_resched() && !cpu_should_die()) {
			ppc64_runlatch_off();

			if (ppc_md.power_save) {
				clear_thread_flag(TIF_POLLING_NRFLAG);
				smp_mb();
				local_irq_disable();

				
				stop_critical_timings();

				
				if (!need_resched() && !cpu_should_die())
					ppc_md.power_save();

				start_critical_timings();

				if (irqs_disabled())
					local_irq_enable();
				set_thread_flag(TIF_POLLING_NRFLAG);

			} else {
				HMT_low();
				HMT_very_low();
			}
		}

		HMT_medium();
		ppc64_runlatch_on();
		rcu_idle_exit();
		tick_nohz_idle_exit();
		if (cpu_should_die()) {
			sched_preempt_enable_no_resched();
			cpu_die();
		}
		schedule_preempt_disabled();
	}
}
Exemple #12
0
/*
 * Generic idle loop implementation
 */
static void cpu_idle_loop(void)
{
	while (1) {
		tick_nohz_idle_enter();

		while (!need_resched()) {
			check_pgt_cache();
			rmb();

			local_irq_disable();
			arch_cpu_idle_enter();

			/*
			 * In poll mode we reenable interrupts and spin.
			 *
			 * Also if we detected in the wakeup from idle
			 * path that the tick broadcast device expired
			 * for us, we don't want to go deep idle as we
			 * know that the IPI is going to arrive right
			 * away
			 */
			if (cpu_idle_force_poll ||
			    tick_check_broadcast_expired() ||
			    __get_cpu_var(idle_force_poll)) {
				cpu_idle_poll();
			} else {
				if (!current_clr_polling_and_test()) {
					stop_critical_timings();
					rcu_idle_enter();
					arch_cpu_idle();
					WARN_ON_ONCE(irqs_disabled());
					rcu_idle_exit();
					start_critical_timings();
				} else {
					local_irq_enable();
				}
				__current_set_polling();
			}
			arch_cpu_idle_exit();
		}
		tick_nohz_idle_exit();
		schedule_preempt_disabled();
		if (cpu_is_offline(smp_processor_id()))
			arch_cpu_idle_dead();

	}
}
Exemple #13
0
void cpu_idle (void)
{
	/* endless idle loop with no priority at all */
	while (1) {
		rcu_idle_enter();
		while (!need_resched()) {
			/*
			 * Mark this as an RCU critical section so that
			 * synchronize_kernel() in the unload path waits
			 * for our completion.
			 */
			default_idle();
		}
		rcu_idle_exit();
		schedule_preempt_disabled();
	}
}
Exemple #14
0
void
cpu_idle(void)
{
	set_thread_flag(TIF_POLLING_NRFLAG);

	while (1) {
		/* FIXME -- EV6 and LCA45 know how to power down
		   the CPU.  */

		rcu_idle_enter();
		while (!need_resched())
			cpu_relax();

		rcu_idle_exit();
		schedule_preempt_disabled();
	}
}
/*
 * The idle thread, has rather strange semantics for calling pm_idle,
 * but this is what x86 does and we need to do the same, so that
 * things like cpuidle get called in the same way.  The only difference
 * is that we always respect 'hlt_counter' to prevent low power idle.
 */
void cpu_idle(void)
{
	local_fiq_enable();

	/* endless idle loop with no priority at all */
	while (1) {
		idle_notifier_call_chain(IDLE_START);
		tick_nohz_idle_enter();
		rcu_idle_enter();
		while (!need_resched()) {
			/*
			 * We need to disable interrupts here
			 * to ensure we don't miss a wakeup call.
			 */
			local_irq_disable();
#ifdef CONFIG_PL310_ERRATA_769419
			wmb();
#endif
			if (hlt_counter) {
				local_irq_enable();
				cpu_relax();
			} else if (!need_resched()) {
				stop_critical_timings();
				if (cpuidle_idle_call())
					pm_idle();
				start_critical_timings();
				/*
				 * pm_idle functions must always
				 * return with IRQs enabled.
				 */
				WARN_ON(irqs_disabled());
			} else
				local_irq_enable();
		}
		rcu_idle_exit();
		tick_nohz_idle_exit();
		idle_notifier_call_chain(IDLE_END);
		schedule_preempt_disabled();
#ifdef CONFIG_HOTPLUG_CPU
		if (cpu_is_offline(smp_processor_id()))
			cpu_die();
#endif
	}
}
Exemple #16
0
/*
 * The idle thread. There's no useful work to be
 * done, so just try to conserve power and have a
 * low exit latency (ie sit in a loop waiting for
 * somebody to say that they'd like to reschedule)
 */
void cpu_idle(void)
{
	int cpu = smp_processor_id();


	current_thread_info()->status |= TS_POLLING;

	if (no_idle_nap) {
		while (1) {
			while (!need_resched())
				cpu_relax();
			schedule();
		}
	}

	/* endless idle loop with no priority at all */
	while (1) {
		tick_nohz_idle_enter();
		rcu_idle_enter();
		while (!need_resched()) {
			if (cpu_is_offline(cpu))
				BUG();  /* no HOTPLUG_CPU */

			local_irq_disable();
			__get_cpu_var(irq_stat).idle_timestamp = jiffies;
			current_thread_info()->status &= ~TS_POLLING;
			/*
			 * TS_POLLING-cleared state must be visible before we
			 * test NEED_RESCHED:
			 */
			smp_mb();

			if (!need_resched())
				_cpu_idle();
			else
				local_irq_enable();
			current_thread_info()->status |= TS_POLLING;
		}
		rcu_idle_exit();
		tick_nohz_idle_exit();
		schedule_preempt_disabled();
	}
}
Exemple #17
0
/*
 * The idle thread. There's no useful work to be
 * done, so just try to conserve power and have a
 * low exit latency (ie sit in a loop waiting for
 * somebody to say that they'd like to reschedule)
 */
void cpu_idle(void)
{
	int cpu = smp_processor_id();

	/*
	 * If we're the non-boot CPU, nothing set the stack canary up
	 * for us.  CPU0 already has it initialized but no harm in
	 * doing it again.  This is a good place for updating it, as
	 * we wont ever return from this function (so the invalid
	 * canaries already on the stack wont ever trigger).
	 */
	boot_init_stack_canary();

	current_thread_info()->status |= TS_POLLING;

	/* endless idle loop with no priority at all */
	while (1) {
		tick_nohz_idle_enter();
		rcu_idle_enter();
		while (!need_resched()) {

			check_pgt_cache();
			rmb();

			if (cpu_is_offline(cpu))
				play_dead();

			local_touch_nmi();
			local_irq_disable();
			/* Don't trace irqs off for idle */
			stop_critical_timings();
			if (cpuidle_idle_call())
				pm_idle();
			start_critical_timings();
		}
		rcu_idle_exit();
		tick_nohz_idle_exit();
		preempt_enable_no_resched();
		schedule();
		preempt_disable();
	}
}
/*
 * The idle thread.  We try to conserve power, while trying to keep
 * overall latency low.  The architecture specific idle is passed
 * a value to indicate the level of "idleness" of the system.
 */
void cpu_idle(void)
{
	/* endless idle loop with no priority at all */
	while (1) {
		void (*idle)(void) = pm_idle;

#ifdef CONFIG_HOTPLUG_CPU
		if (cpu_is_offline(smp_processor_id()))
			cpu_die();
#endif
		if (!idle)
			idle = default_idle;
		tick_nohz_idle_enter();
		rcu_idle_enter();
		while (!need_resched())
			idle();
		rcu_idle_exit();
		tick_nohz_idle_exit();
		schedule_preempt_disabled();
	}
}
Exemple #19
0
void cpu_idle(void)
{
	set_thread_flag(TIF_POLLING_NRFLAG);

	/* endless idle loop with no priority at all */
	while (1) {
		void (*idle)(void) = pm_idle;

		if (!idle)
			idle = default_idle;

		tick_nohz_idle_enter();
		rcu_idle_enter();
		while (!need_resched())
			idle();
		rcu_idle_exit();
		tick_nohz_idle_exit();

		schedule_preempt_disabled();
		check_pgt_cache();
	}
}
void cpu_idle(void)
{
	
	for (;;) {
		rcu_idle_enter();
		while (!need_resched()) {
			void (*idle)(void);

			smp_rmb();
			idle = pm_idle;
			if (!idle) {
#if defined(CONFIG_SMP) && !defined(CONFIG_HOTPLUG_CPU)
				idle = poll_idle;
#else  
				idle = default_idle;
#endif 
			}
			idle();
		}
		rcu_idle_exit();

		schedule_preempt_disabled();
	}
}
Exemple #21
0
/*
 * The idle thread. There's no useful work to be done, so just try to conserve
 * power and have a low exit latency (ie sit in a loop waiting for somebody to
 * say that they'd like to reschedule)
 */
void __noreturn cpu_idle(void)
{
	int cpu;

	/* CPU is going idle. */
	cpu = smp_processor_id();

	/* endless idle loop with no priority at all */
	while (1) {
		tick_nohz_idle_enter();
		rcu_idle_enter();
		while (!need_resched() && cpu_online(cpu)) {
#ifdef CONFIG_MIPS_MT_SMTC
			extern void smtc_idle_loop_hook(void);

			smtc_idle_loop_hook();
#endif

			if (cpu_wait) {
				/* Don't trace irqs off for idle */
				stop_critical_timings();
				(*cpu_wait)();
				start_critical_timings();
			}
		}
#ifdef CONFIG_HOTPLUG_CPU
		if (!cpu_online(cpu) && !cpu_isset(cpu, cpu_callin_map) &&
		    (system_state == SYSTEM_RUNNING ||
		     system_state == SYSTEM_BOOTING))
			play_dead();
#endif
		rcu_idle_exit();
		tick_nohz_idle_exit();
		schedule_preempt_disabled();
	}
}
Exemple #22
0
/*
 * The idle thread. There's no useful work to be done, so just try to conserve
 * power and have a low exit latency (ie sit in a loop waiting for somebody to
 * say that they'd like to reschedule)
 */
void cpu_idle(void)
{
	unsigned int cpu = smp_processor_id();

	set_thread_flag(TIF_POLLING_NRFLAG);

	/* endless idle loop with no priority at all */
	while (1) {
		tick_nohz_idle_enter();
		rcu_idle_enter();

		while (!need_resched()) {
			check_pgt_cache();
			rmb();

			if (cpu_is_offline(cpu))
				play_dead();

			local_irq_disable();
			/* Don't trace irqs off for idle */
			stop_critical_timings();
			if (cpuidle_idle_call())
				sh_idle();
			/*
			 * Sanity check to ensure that sh_idle() returns
			 * with IRQs enabled
			 */
			WARN_ON(irqs_disabled());
			start_critical_timings();
		}

		rcu_idle_exit();
		tick_nohz_idle_exit();
		schedule_preempt_disabled();
	}
}
/*
 * the idle thread
 * - there's no useful work to be done, so just try to conserve power and have
 *   a low exit latency (ie sit in a loop waiting for somebody to say that
 *   they'd like to reschedule)
 */
void cpu_idle(void)
{
	/* endless idle loop with no priority at all */
	for (;;) {
		rcu_idle_enter();
		while (!need_resched()) {
			void (*idle)(void);

			smp_rmb();
			idle = pm_idle;
			if (!idle) {
#if defined(CONFIG_SMP) && !defined(CONFIG_HOTPLUG_CPU)
				idle = poll_idle;
#else  /* CONFIG_SMP && !CONFIG_HOTPLUG_CPU */
				idle = default_idle;
#endif /* CONFIG_SMP && !CONFIG_HOTPLUG_CPU */
			}
			idle();
		}
		rcu_idle_exit();

		schedule_preempt_disabled();
	}
}
Exemple #24
0
/**
 * cpuidle_idle_call - the main idle function
 *
 * NOTE: no locks or semaphores should be used here
 */
static void cpuidle_idle_call(void)
{
	struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
	int next_state, entered_state;
	bool broadcast;

	/*
	 * Check if the idle task must be rescheduled. If it is the
	 * case, exit the function after re-enabling the local irq.
	 */
	if (need_resched()) {
		local_irq_enable();
		return;
	}

	/*
	 * During the idle period, stop measuring the disabled irqs
	 * critical sections latencies
	 */
	stop_critical_timings();

	/*
	 * Tell the RCU framework we are entering an idle section,
	 * so no more rcu read side critical sections and one more
	 * step to the grace period
	 */
	rcu_idle_enter();

	/*
	 * Ask the cpuidle framework to choose a convenient idle state.
	 * Fall back to the default arch idle method on errors.
	 */
	next_state = cpuidle_select(drv, dev);
	if (next_state < 0) {
use_default:
		/*
		 * We can't use the cpuidle framework, let's use the default
		 * idle routine.
		 */
		if (current_clr_polling_and_test())
			local_irq_enable();
		else
			arch_cpu_idle();

		goto exit_idle;
	}


	/*
	 * The idle task must be scheduled, it is pointless to
	 * go to idle, just update no idle residency and get
	 * out of this function
	 */
	if (current_clr_polling_and_test()) {
		dev->last_residency = 0;
		entered_state = next_state;
		local_irq_enable();
		goto exit_idle;
	}

	broadcast = !!(drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP);

	/*
	 * Tell the time framework to switch to a broadcast timer
	 * because our local timer will be shutdown. If a local timer
	 * is used from another cpu as a broadcast timer, this call may
	 * fail if it is not available
	 */
	if (broadcast &&
	    clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &dev->cpu))
		goto use_default;

	trace_cpu_idle_rcuidle(next_state, dev->cpu);

	/*
	 * Enter the idle state previously returned by the governor decision.
	 * This function will block until an interrupt occurs and will take
	 * care of re-enabling the local interrupts
	 */
	entered_state = cpuidle_enter(drv, dev, next_state);

	trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);

	if (broadcast)
		clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &dev->cpu);

	/*
	 * Give the governor an opportunity to reflect on the outcome
	 */
	cpuidle_reflect(dev, entered_state);

exit_idle:
	__current_set_polling();

	/*
	 * It is up to the idle functions to reenable local interrupts
	 */
	if (WARN_ON_ONCE(irqs_disabled()))
		local_irq_enable();

	rcu_idle_exit();
	start_critical_timings();
}
Exemple #25
0
/**
 * cpuidle_idle_call - the main idle function
 *
 * NOTE: no locks or semaphores should be used here
 *
 * On archs that support TIF_POLLING_NRFLAG, is called with polling
 * set, and it returns with polling set.  If it ever stops polling, it
 * must clear the polling bit.
 */
static void cpuidle_idle_call(void)
{
	struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
	int next_state, entered_state;
	unsigned int broadcast;
	bool reflect;

	/*
	 * Check if the idle task must be rescheduled. If it is the
	 * case, exit the function after re-enabling the local irq.
	 */
	if (need_resched()) {
		local_irq_enable();
		return;
	}

	/*
	 * During the idle period, stop measuring the disabled irqs
	 * critical sections latencies
	 */
	stop_critical_timings();

	/*
	 * Tell the RCU framework we are entering an idle section,
	 * so no more rcu read side critical sections and one more
	 * step to the grace period
	 */
	rcu_idle_enter();

	if (cpuidle_not_available(drv, dev))
		goto use_default;

	/*
	 * Suspend-to-idle ("freeze") is a system state in which all user space
	 * has been frozen, all I/O devices have been suspended and the only
	 * activity happens here and in iterrupts (if any).  In that case bypass
	 * the cpuidle governor and go stratight for the deepest idle state
	 * available.  Possibly also suspend the local tick and the entire
	 * timekeeping to prevent timer interrupts from kicking us out of idle
	 * until a proper wakeup interrupt happens.
	 */
	if (idle_should_freeze()) {
		entered_state = cpuidle_enter_freeze(drv, dev);
		if (entered_state >= 0) {
			local_irq_enable();
			goto exit_idle;
		}

		reflect = false;
		next_state = cpuidle_find_deepest_state(drv, dev);
	} else {
		reflect = true;
		/*
		 * Ask the cpuidle framework to choose a convenient idle state.
		 */
		next_state = cpuidle_select(drv, dev);
	}
	/* Fall back to the default arch idle method on errors. */
	if (next_state < 0)
		goto use_default;

	/*
	 * The idle task must be scheduled, it is pointless to
	 * go to idle, just update no idle residency and get
	 * out of this function
	 */
	if (current_clr_polling_and_test()) {
		dev->last_residency = 0;
		entered_state = next_state;
		local_irq_enable();
		goto exit_idle;
	}

	broadcast = drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP;

	/*
	 * Tell the time framework to switch to a broadcast timer
	 * because our local timer will be shutdown. If a local timer
	 * is used from another cpu as a broadcast timer, this call may
	 * fail if it is not available
	 */
	if (broadcast && tick_broadcast_enter())
		goto use_default;

	/* Take note of the planned idle state. */
	idle_set_state(this_rq(), &drv->states[next_state]);

	/*
	 * Enter the idle state previously returned by the governor decision.
	 * This function will block until an interrupt occurs and will take
	 * care of re-enabling the local interrupts
	 */
	entered_state = cpuidle_enter(drv, dev, next_state);

	/* The cpu is no longer idle or about to enter idle. */
	idle_set_state(this_rq(), NULL);

	if (broadcast)
		tick_broadcast_exit();

	/*
	 * Give the governor an opportunity to reflect on the outcome
	 */
	if (reflect)
		cpuidle_reflect(dev, entered_state);

exit_idle:
	__current_set_polling();

	/*
	 * It is up to the idle functions to reenable local interrupts
	 */
	if (WARN_ON_ONCE(irqs_disabled()))
		local_irq_enable();

	rcu_idle_exit();
	start_critical_timings();
	return;

use_default:
	/*
	 * We can't use the cpuidle framework, let's use the default
	 * idle routine.
	 */
	if (current_clr_polling_and_test())
		local_irq_enable();
	else
		arch_cpu_idle();

	goto exit_idle;
}
/**
 * cpuidle_idle_call - the main idle function
 *
 * NOTE: no locks or semaphores should be used here
 *
 * On archs that support TIF_POLLING_NRFLAG, is called with polling
 * set, and it returns with polling set.  If it ever stops polling, it
 * must clear the polling bit.
 */
static void cpuidle_idle_call(void)
{
	struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
	int next_state, entered_state;

	/*
	 * Check if the idle task must be rescheduled. If it is the
	 * case, exit the function after re-enabling the local irq.
	 */
	if (need_resched()) {
		local_irq_enable();
		return;
	}

	/*
	 * During the idle period, stop measuring the disabled irqs
	 * critical sections latencies
	 */
	stop_critical_timings();

	/*
	 * Tell the RCU framework we are entering an idle section,
	 * so no more rcu read side critical sections and one more
	 * step to the grace period
	 */
	rcu_idle_enter();

	/*
	 * Check if the cpuidle framework is ready, otherwise fallback
	 * to the default arch specific idle method
	 */
	next_state = cpuidle_select(drv, dev);
	if (next_state < 0) {
		default_idle_call();
		goto exit_idle;
	}

	/*
	 * The idle task must be scheduled, it is pointless to
	 * go to idle, just update no idle residency and get
	 * out of this function
	 */
	if (current_clr_polling_and_test()) {
		dev->last_residency = 0;
		entered_state = next_state;
		local_irq_enable();
		goto exit_idle;
	}

	/* Take note of the planned idle state. */
	idle_set_state(this_rq(), &drv->states[next_state]);

	/*
	 * Enter the idle state previously returned by the governor decision.
	 * This function will block until an interrupt occurs and will take
	 * care of re-enabling the local interrupts
	 */
	entered_state = cpuidle_enter(drv, dev, next_state);

	/* The cpu is no longer idle or about to enter idle. */
	idle_set_state(this_rq(), NULL);

	if (entered_state == -EBUSY) {
		default_idle_call();
		goto exit_idle;
	}

	/*
	 * Give the governor an opportunity to reflect on the outcome
	 */
	cpuidle_reflect(dev, entered_state);

exit_idle:
	__current_set_polling();

	/*
	 * It is up to the idle functions to reenable local interrupts
	 */
	if (WARN_ON_ONCE(irqs_disabled()))
		local_irq_enable();

	rcu_idle_exit();
	start_critical_timings();
}
Exemple #27
0
void fake_acquire_cpu(void)
{
	if (pthread_mutex_lock(&cpu_lock))
		exit(-1);
	rcu_idle_exit();
}
Exemple #28
0
/**
 * cpuidle_idle_call - the main idle function
 *
 * NOTE: no locks or semaphores should be used here
 *
 * On archs that support TIF_POLLING_NRFLAG, is called with polling
 * set, and it returns with polling set.  If it ever stops polling, it
 * must clear the polling bit.
 */
static void cpuidle_idle_call(void)
{
	struct cpuidle_device *dev = cpuidle_get_device();
	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
	int next_state, entered_state;

	/*
	 * Check if the idle task must be rescheduled. If it is the
	 * case, exit the function after re-enabling the local irq.
	 */
	if (need_resched()) {
		local_irq_enable();
		return;
	}

	/*
	 * Tell the RCU framework we are entering an idle section,
	 * so no more rcu read side critical sections and one more
	 * step to the grace period
	 */
	rcu_idle_enter();

	if (cpuidle_not_available(drv, dev)) {
		default_idle_call();
		goto exit_idle;
	}

	/*
	 * Suspend-to-idle ("freeze") is a system state in which all user space
	 * has been frozen, all I/O devices have been suspended and the only
	 * activity happens here and in iterrupts (if any).  In that case bypass
	 * the cpuidle governor and go stratight for the deepest idle state
	 * available.  Possibly also suspend the local tick and the entire
	 * timekeeping to prevent timer interrupts from kicking us out of idle
	 * until a proper wakeup interrupt happens.
	 */
	if (idle_should_freeze()) {
		entered_state = cpuidle_enter_freeze(drv, dev);
		if (entered_state > 0) {
			local_irq_enable();
			goto exit_idle;
		}

		next_state = cpuidle_find_deepest_state(drv, dev);
		call_cpuidle(drv, dev, next_state);
	} else {
		/*
		 * Ask the cpuidle framework to choose a convenient idle state.
		 */
		next_state = cpuidle_select(drv, dev);
		entered_state = call_cpuidle(drv, dev, next_state);
		/*
		 * Give the governor an opportunity to reflect on the outcome
		 */
		cpuidle_reflect(dev, entered_state);
	}

exit_idle:
	__current_set_polling();

	/*
	 * It is up to the idle functions to reenable local interrupts
	 */
	if (WARN_ON_ONCE(irqs_disabled()))
		local_irq_enable();

	rcu_idle_exit();
}