linux-kernel - [tip:sched/core] cpuidle: Set polling in poll

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Message-ID: <tip-84c407084137d4e491b07ea5ff8665d19106a5ac@git.kernel.org>
Date:	Thu, 5 Jun 2014 07:37:07 -0700
From:	tip-bot for Andy Lutomirski <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...nel.org,
	torvalds@...ux-foundation.org, peterz@...radead.org,
	luto@...capital.net, tglx@...utronix.de, rjw@...ysocki.net,
	daniel.lezcano@...aro.org
Subject: [tip:sched/core] cpuidle: Set polling in poll_idle

Commit-ID:  84c407084137d4e491b07ea5ff8665d19106a5ac
Gitweb:     http://git.kernel.org/tip/84c407084137d4e491b07ea5ff8665d19106a5ac
Author:     Andy Lutomirski <luto@...capital.net>
AuthorDate: Wed, 4 Jun 2014 10:31:14 -0700
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Thu, 5 Jun 2014 12:09:49 +0200

cpuidle: Set polling in poll_idle

poll_idle is the archetypal polling idle loop; tell the core idle
code about it.

This avoids pointless IPIs when all of the other cpuidle states are
disabled.

Signed-off-by: Andy Lutomirski <luto@...capital.net>
Signed-off-by: Peter Zijlstra <peterz@...radead.org>
Cc: nicolas.pitre@...aro.org
Cc: umgwanakikbuti@...il.com
Cc: Daniel Lezcano <daniel.lezcano@...aro.org>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Rafael J. Wysocki <rjw@...ysocki.net>
Cc: linux-kernel@...r.kernel.org
Cc: linux-pm@...r.kernel.org
Link: http://lkml.kernel.org/r/c65ce49615d338bae8fb79df5daffab19353c900.1401902905.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 drivers/cpuidle/driver.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c
index 136d6a2..9634f20 100644
--- a/drivers/cpuidle/driver.c
+++ b/drivers/cpuidle/driver.c
@@ -187,8 +187,11 @@ static int poll_idle(struct cpuidle_device *dev,
 
 	t1 = ktime_get();
 	local_irq_enable();
-	while (!need_resched())
-		cpu_relax();
+	if (!current_set_polling_and_test()) {
+		while (!need_resched())
+			cpu_relax();
+	}
+	current_clr_polling();
 
 	t2 = ktime_get();
 	diff = ktime_to_us(ktime_sub(t2, t1));
--
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