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Commit af695cd9 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

mn10300: Use generic idle loop 



default_idle() boils down to safe_halt() and the other option is idle
polling. Use the core functionality.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: default avatarCc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Link: http://lkml.kernel.org/r/20130321215234.822656036@linutronix.de


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent cdbedc61

arch/mn10300/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ config MN10300 
	select MODULES_USE_ELF_RELA

	select OLD_SIGSUSPEND3

	select OLD_SIGACTION

	select GENERIC_IDLE_LOOP



config AM33_2

	def_bool n

arch/mn10300/kernel/process.c

+6 −64
Original line number Diff line number Diff line
@@ -50,77 +50,19 @@ unsigned long thread_saved_pc(struct task_struct *tsk) 
void (*pm_power_off)(void);

EXPORT_SYMBOL(pm_power_off);



#if !defined(CONFIG_SMP) || defined(CONFIG_HOTPLUG_CPU)

/*

 * we use this if we don't have any better idle routine

 */

static void default_idle(void)

{

	local_irq_disable();

	if (!need_resched())

		safe_halt();

	else

		local_irq_enable();

}



#else /* !CONFIG_SMP || CONFIG_HOTPLUG_CPU  */

/*

 * On SMP it's slightly faster (but much more power-consuming!)

 * to poll the ->work.need_resched flag instead of waiting for the

 * cross-CPU IPI to arrive. Use this option with caution.

 *

 * tglx: No idea why this depends on HOTPLUG_CPU !?!

 */

static inline void poll_idle(void)

{

	int oldval;



	local_irq_enable();



	/*

	 * Deal with another CPU just having chosen a thread to

	 * run here:

	 */

	oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED);



	if (!oldval) {

		set_thread_flag(TIF_POLLING_NRFLAG);

		while (!need_resched())

			cpu_relax();

		clear_thread_flag(TIF_POLLING_NRFLAG);

	} else {

		set_need_resched();

	}

}

#endif /* !CONFIG_SMP || CONFIG_HOTPLUG_CPU */



/*

 * 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)

#if !defined(CONFIG_SMP) || defined(CONFIG_HOTPLUG_CPU)

void arch_cpu_idle(void)

{

	/* endless idle loop with no priority at all */

	for (;;) {

		rcu_idle_enter();

		while (!need_resched()) {

			void (*idle)(void);



			smp_rmb();

			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();

	}

	safe_halt();

}

#endif



void release_segments(struct mm_struct *mm)

{

arch/mn10300/kernel/smp.c

+1 −1
Original line number Diff line number Diff line
@@ -675,7 +675,7 @@ int __init start_secondary(void *unused) 
#ifdef CONFIG_GENERIC_CLOCKEVENTS

	init_clockevents();

#endif

	cpu_idle();

	cpu_startup_entry(CPUHP_ONLINE);

	return 0;

}