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Commit 42763935 authored by Tony Luck's avatar Tony Luck
Browse files

[IA64] Simplify cpu_idle_wait 

This is just Venki's patch[*] for x86 ported to ia64.

* http://marc.info/?l=linux-kernel&m=120249201318159&w=2



Acked-by: default avatarVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
parent aa91a2e9

arch/ia64/kernel/process.c

+15 −29
Original line number Diff line number Diff line
@@ -52,7 +52,6 @@ 
#include "sigframe.h"



void (*ia64_mark_idle)(int);

static DEFINE_PER_CPU(unsigned int, cpu_idle_state);



unsigned long boot_option_idle_override = 0;

EXPORT_SYMBOL(boot_option_idle_override);
@@ -254,33 +253,23 @@ static inline void play_dead(void) 
}

#endif /* CONFIG_HOTPLUG_CPU */



void cpu_idle_wait(void)

static void do_nothing(void *unused)

{

	unsigned int cpu, this_cpu = get_cpu();

	cpumask_t map;

	cpumask_t tmp = current->cpus_allowed;



	set_cpus_allowed(current, cpumask_of_cpu(this_cpu));

	put_cpu();



	cpus_clear(map);

	for_each_online_cpu(cpu) {

		per_cpu(cpu_idle_state, cpu) = 1;

		cpu_set(cpu, map);

}



	__get_cpu_var(cpu_idle_state) = 0;



	wmb();

	do {

		ssleep(1);

		for_each_online_cpu(cpu) {

			if (cpu_isset(cpu, map) && !per_cpu(cpu_idle_state, cpu))

				cpu_clear(cpu, map);

		}

		cpus_and(map, map, cpu_online_map);

	} while (!cpus_empty(map));

	set_cpus_allowed(current, tmp);

/*

 * cpu_idle_wait - Used to ensure that all the CPUs discard old value of

 * pm_idle and update to new pm_idle value. Required while changing pm_idle

 * handler on SMP systems.

 *

 * Caller must have changed pm_idle to the new value before the call. Old

 * pm_idle value will not be used by any CPU after the return of this function.

 */

void cpu_idle_wait(void)

{

	smp_mb();

	/* kick all the CPUs so that they exit out of pm_idle */

	smp_call_function(do_nothing, NULL, 0, 1);

}

EXPORT_SYMBOL_GPL(cpu_idle_wait);
@@ -308,9 +297,6 @@ cpu_idle (void) 
#ifdef CONFIG_SMP

			min_xtp();

#endif

			if (__get_cpu_var(cpu_idle_state))

				__get_cpu_var(cpu_idle_state) = 0;



			rmb();

			if (mark_idle)

				(*mark_idle)(1);