Re: [PATCH v2] arm64: cpuidle: add __init section marker to arm_cpuidle_init

From: Krzysztof Kozlowski
Date: Thu Jul 02 2015 - 01:24:03 EST


On 02.07.2015 13:58, Jisheng Zhang wrote:
> Dear Krzysztof,
>
> On Thu, 2 Jul 2015 12:59:44 +0900
> Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx> wrote:
>
>> 2015-07-02 11:14 GMT+09:00 Jisheng Zhang <jszhang@xxxxxxxxxxx>:
>>> It is not needed after booting, this patch moves the arm_cpuidle_init()
>>> function to the __init section.
>>>
>>> Signed-off-by: Jisheng Zhang <jszhang@xxxxxxxxxxx>
>>> ---
>>> arch/arm64/include/asm/cpuidle.h | 2 +-
>>> arch/arm64/kernel/cpuidle.c | 2 +-
>>> 2 files changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/arch/arm64/include/asm/cpuidle.h b/arch/arm64/include/asm/cpuidle.h
>>> index 0f74f05..5748d3b 100644
>>> --- a/arch/arm64/include/asm/cpuidle.h
>>> +++ b/arch/arm64/include/asm/cpuidle.h
>>> @@ -4,7 +4,7 @@
>>> #include <asm/proc-fns.h>
>>>
>>> #ifdef CONFIG_CPU_IDLE
>>> -extern int arm_cpuidle_init(unsigned int cpu);
>>> +extern int __init arm_cpuidle_init(unsigned int cpu);
>>
>> No, not here but...
>>
>>> extern int arm_cpuidle_suspend(int index);
>>> #else
>>> static inline int arm_cpuidle_init(unsigned int cpu)
>>
>> ... here so the stub for !CONFIG_CPU_IDLE would be marked as well.
>
> when !CONFIG_CPU_IDLE, arm_cpuidle_init() is inlined, and just return -EOPNOTSUPP;
> Per my understanding, it will be optimized out by compiler. I'm not sure whether
> there is any benefit to mark inlined function as __init. But Per my check, all
> other inlined functions in linux kernel have no __init. What do you think?

Yes, you're right, the inline is sufficient so this means that actually
the first patch was correct. The __init is not needed in extern
declaration. For both versions then:

Reviewed-by: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx>

Best regards,
Krzysztof

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