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Subject[RFC PATCH] cpuidle: Use a lighter barrier in snooze_loop()
Date
Using smp_mb() here so that the bit clear is not reordered is an overkill.

It is more appropriate to use smp_mb__after_atomic() which ensures that the
bit clear is not reordered.

Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
---
drivers/cpuidle/cpuidle-powernv.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c
index 7d3a349..b0bfcbe 100644
--- a/drivers/cpuidle/cpuidle-powernv.c
+++ b/drivers/cpuidle/cpuidle-powernv.c
@@ -48,7 +48,8 @@ static int snooze_loop(struct cpuidle_device *dev,
HMT_medium();
ppc64_runlatch_on();
clear_thread_flag(TIF_POLLING_NRFLAG);
- smp_mb();
+ /* ensure bit clear is not reordered */
+ smp_mb__after_atomic();
return index;
}

--
1.9.1


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