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Commit 0dc8153c authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

tile: Use generic idle loop 



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>
Acked-by: default avatarChris Metcalf <cmetcalf@tilera.com>
Link: http://lkml.kernel.org/r/20130321215235.348460344@linutronix.de


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent e26ef8fe

arch/tile/Kconfig

+1 −0
Original line number Original line Diff line number Diff line
@@ -22,6 +22,7 @@ config TILE 
	select ARCH_HAVE_NMI_SAFE_CMPXCHG

	select ARCH_HAVE_NMI_SAFE_CMPXCHG

	select GENERIC_CLOCKEVENTS

	select GENERIC_CLOCKEVENTS

	select MODULES_USE_ELF_RELA

	select MODULES_USE_ELF_RELA

	select GENERIC_IDLE_LOOP





# FIXME: investigate whether we need/want these options.

# FIXME: investigate whether we need/want these options.

#	select HAVE_IOREMAP_PROT

#	select HAVE_IOREMAP_PROT

arch/tile/kernel/process.c

+9 −56
Original line number Original line Diff line number Diff line
@@ -40,13 +40,11 @@ 
#include <arch/abi.h>

#include <arch/abi.h>

#include <arch/sim_def.h>

#include <arch/sim_def.h>







/*

/*

 * Use the (x86) "idle=poll" option to prefer low latency when leaving the

 * Use the (x86) "idle=poll" option to prefer low latency when leaving the

 * idle loop over low power while in the idle loop, e.g. if we have

 * idle loop over low power while in the idle loop, e.g. if we have

 * one thread per core and we want to get threads out of futex waits fast.

 * one thread per core and we want to get threads out of futex waits fast.

 */

 */

static int no_idle_nap;

static int __init idle_setup(char *str)

static int __init idle_setup(char *str)

{

{

	if (!str)

	if (!str)
@@ -54,64 +52,19 @@ static int __init idle_setup(char *str) 




	if (!strcmp(str, "poll")) {

	if (!strcmp(str, "poll")) {

		pr_info("using polling idle threads.\n");

		pr_info("using polling idle threads.\n");

		no_idle_nap = 1;

		cpu_idle_poll_ctrl(true);

	} else if (!strcmp(str, "halt"))

		no_idle_nap = 0;

	else

		return -1;



		return 0;

		return 0;

	} else if (!strcmp(str, "halt")) {

		return 0;

	}

	return -1;

}

}

early_param("idle", idle_setup);

early_param("idle", idle_setup);





/*

void arch_cpu_idle(void)

 * 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;

	__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();

	_cpu_idle();

			else

				local_irq_enable();

			current_thread_info()->status |= TS_POLLING;

		}

		rcu_idle_exit();

		tick_nohz_idle_exit();

		schedule_preempt_disabled();

	}

}

}





/*

/*

arch/tile/kernel/smpboot.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -207,7 +207,7 @@ void __cpuinit online_secondary(void) 
	/* Set up tile-timer clock-event device on this cpu */

	/* Set up tile-timer clock-event device on this cpu */

	setup_tile_timer();

	setup_tile_timer();





	cpu_idle();

	cpu_startup_entry(CPUHP_ONLINE);

}

}





int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tidle)

int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tidle)