Re: [PATCH 2/2] ARM: cpuidle: make arm_cpuidle_suspend() a bit more efficient
From: Daniel Lezcano
Date: Fri Mar 25 2016 - 07:52:55 EST
On 03/24/2016 06:11 AM, Jisheng Zhang wrote:
Currently, we check cpuidle_ops.suspend every time when entering a
low-power idle state. But this check could be avoided in this hot path
by moving it into arm_cpuidle_init() to reduce arm_cpuidle_suspend()
overhead a bit.
Signed-off-by: Jisheng Zhang <jszhang@xxxxxxxxxxx>
---
arch/arm/kernel/cpuidle.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)
diff --git a/arch/arm/kernel/cpuidle.c b/arch/arm/kernel/cpuidle.c
index f108d8f..bf68d49 100644
--- a/arch/arm/kernel/cpuidle.c
+++ b/arch/arm/kernel/cpuidle.c
@@ -52,13 +52,9 @@ int arm_cpuidle_simple_enter(struct cpuidle_device *dev,
*/
int arm_cpuidle_suspend(int index)
{
- int ret = -EOPNOTSUPP;
int cpu = smp_processor_id();
- if (cpuidle_ops[cpu].suspend)
- ret = cpuidle_ops[cpu].suspend(index);
-
- return ret;
+ return cpuidle_ops[cpu].suspend(index);
}
I agree with the optimization but, same comment than the previous patch,
it should be handled in arm_cpuidle_read_ops.
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