[tip:sched/core] cpuidle: Set polling in poll_idle

tip-bot for Andy Lutomirski
2014-06-05T14:38:09Z

Commit-ID: 84c407084137d4e491b07ea5ff8665d19106a5ac
Gitweb: http://git.kernel.org/tip/84c407084137d4e491b07ea5ff8665d19106a5ac
Author: Andy Lutomirski <luto@amacapital.net>
AuthorDate: Wed, 4 Jun 2014 10:31:14 -0700
Committer: Ingo Molnar <mingo@kernel.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@amacapital.net>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: nicolas.pitre@linaro.org
Cc: umgwanakikbuti@gmail.com
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: linux-kernel@vger.kernel.org
Cc: linux-pm@vger.kernel.org
Link: http://lkml.kernel.org/r/c65ce49615d338bae8fb79df5daffab19353c900.1401902905.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.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));