[patch 1/2]intel_idle: fix misuse API - resend

[patch 1/2]intel_idle: fix misuse API - resend

[Shaohua Li]

smp_call_function() only lets all other CPUs execute specific
function, while we expect all CPUs do in intel_idle. Without
the fix, we could have one cpu has auto_demotion enabled or
has no boradcast timer setup. Usually we don't see impact
because auto demotion just harms power and the intel_idle init
is called in CPU 0, where boradcast timer delivers interrupt,
but this still could be a problem.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>

---
 drivers/idle/intel_idle.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Index: linux/drivers/idle/intel_idle.c
===================================================================
--- linux.orig/drivers/idle/intel_idle.c	2011-05-27 16:47:06.000000000 +0800
+++ linux/drivers/idle/intel_idle.c	2011-06-03 09:47:30.000000000 +0800
@@ -367,7 +367,7 @@ static int intel_idle_probe(void)
 	if (boot_cpu_has(X86_FEATURE_ARAT))	/* Always Reliable APIC Timer */
 		lapic_timer_reliable_states = LAPIC_TIMER_ALWAYS_RELIABLE;
 	else {
-		smp_call_function(__setup_broadcast_timer, (void *)true, 1);
+		on_each_cpu(__setup_broadcast_timer, (void *)true, 1);
 		register_cpu_notifier(&setup_broadcast_notifier);
 	}
 
@@ -459,7 +459,7 @@ static int intel_idle_cpuidle_devices_in
 		}
 	}
 	if (auto_demotion_disable_flags)
-		smp_call_function(auto_demotion_disable, NULL, 1);
+		on_each_cpu(auto_demotion_disable, NULL, 1);
 
 	return 0;
 }
@@ -499,7 +499,7 @@ static void __exit intel_idle_exit(void)
 	cpuidle_unregister_driver(&intel_idle_driver);
 
 	if (lapic_timer_reliable_states != LAPIC_TIMER_ALWAYS_RELIABLE) {
-		smp_call_function(__setup_broadcast_timer, (void *)false, 1);
+		on_each_cpu(__setup_broadcast_timer, (void *)false, 1);
 		unregister_cpu_notifier(&setup_broadcast_notifier);
 	}
 

Re: [patch 1/2]intel_idle: fix misuse API - resend

[Shaohua Li]

On Fri, 2011-06-03 at 10:42 +0800, Shaohua Li wrote:
> smp_call_function() only lets all other CPUs execute specific
> function, while we expect all CPUs do in intel_idle. Without
> the fix, we could have one cpu has auto_demotion enabled or
> has no boradcast timer setup. Usually we don't see impact
> because auto demotion just harms power and the intel_idle init
> is called in CPU 0, where boradcast timer delivers interrupt,
> but this still could be a problem.
has any comments on these? NACK or merge?