linux-kernel - [PATCH 3/3] cpuidle: Using the wake_up_all_idle

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Message-Id: <1409815075-4180-3-git-send-email-chuansheng.liu@intel.com>
Date:	Thu,  4 Sep 2014 15:17:55 +0800
From:	Chuansheng Liu <chuansheng.liu@...el.com>
To:	peterz@...radead.org, luto@...capital.net,
	daniel.lezcano@...aro.org, rjw@...ysocki.net, mingo@...hat.com
Cc:	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
	changcheng.liu@...el.com, xiaoming.wang@...el.com,
	souvik.k.chakravarty@...el.com, chuansheng.liu@...el.com
Subject: [PATCH 3/3] cpuidle: Using the wake_up_all_idle_cpus() to wake up all idle cpus

Currently kick_all_cpus_sync() or smp_call_function() can not
break the polling idle cpu immediately.

Here using wake_up_all_idle_cpus() which can wake up the polling idle
cpu quickly is much helpful for power.

Signed-off-by: Chuansheng Liu <chuansheng.liu@...el.com>
---
 drivers/cpuidle/cpuidle.c |    9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index ee9df5e..d31e04c 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -223,7 +223,7 @@ void cpuidle_uninstall_idle_handler(void)
 {
 	if (enabled_devices) {
 		initialized = 0;
-		kick_all_cpus_sync();
+		wake_up_all_idle_cpus();
 	}
 }
 
@@ -530,11 +530,6 @@ EXPORT_SYMBOL_GPL(cpuidle_register);
 
 #ifdef CONFIG_SMP
 
-static void smp_callback(void *v)
-{
-	/* we already woke the CPU up, nothing more to do */
-}
-
 /*
  * This function gets called when a part of the kernel has a new latency
  * requirement.  This means we need to get all processors out of their C-state,
@@ -544,7 +539,7 @@ static void smp_callback(void *v)
 static int cpuidle_latency_notify(struct notifier_block *b,
 		unsigned long l, void *v)
 {
-	smp_call_function(smp_callback, NULL, 1);
+	wake_up_all_idle_cpus();
 	return NOTIFY_OK;
 }
 
-- 
1.7.9.5

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