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Commit f37f435f authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

smp: Implement kick_all_cpus_sync() 



Will replace the misnomed cpu_idle_wait() function which is copied a
gazillion times all over arch/*

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120507175652.049316594@linutronix.de
parent 9cd75e13

include/linux/smp.h

+4 −0
Original line number Diff line number Diff line
@@ -81,6 +81,8 @@ void __smp_call_function_single(int cpuid, struct call_single_data *data, 
int smp_call_function_any(const struct cpumask *mask,

			  smp_call_func_t func, void *info, int wait);



void kick_all_cpus_sync(void);



/*

 * Generic and arch helpers

 */
@@ -192,6 +194,8 @@ smp_call_function_any(const struct cpumask *mask, smp_call_func_t func, 
	return smp_call_function_single(0, func, info, wait);

}



static inline void kick_all_cpus_sync(void) {  }



#endif /* !SMP */



/*

kernel/smp.c

+23 −0
Original line number Diff line number Diff line
@@ -795,3 +795,26 @@ void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info), 
	}

}

EXPORT_SYMBOL(on_each_cpu_cond);



static void do_nothing(void *unused)

{

}



/**

 * kick_all_cpus_sync - Force all cpus out of idle

 *

 * Used to synchronize the update of pm_idle function pointer. It's

 * called after the pointer is updated and returns after the dummy

 * callback function has been executed on all cpus. The execution of

 * the function can only happen on the remote cpus after they have

 * left the idle function which had been called via pm_idle function

 * pointer. So it's guaranteed that nothing uses the previous pointer

 * anymore.

 */

void kick_all_cpus_sync(void)

{

	/* Make sure the change is visible before we kick the cpus */

	smp_mb();

	smp_call_function(do_nothing, NULL, 1);

}

EXPORT_SYMBOL_GPL(kick_all_cpus_sync);