[PATCH v2 1/5] cpuidle: Set polling in poll_idle

Andy Lutomirski
2014-06-04T17:31:29Z

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>
---
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));
--
1.9.3