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Date: Wed, 16 Nov 2011 10:40:17 -0800
From: Paul Turner <pjt@google.com>
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To: Peter Zijlstra <peterz@infradead.org>
CC: Il Han <corone.il.han@gmail.com>, Ingo Molnar <mingo@elte.hu>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] sched: add the inline keyword to the prototype.
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On 11/16/2011 01:00 AM, Peter Zijlstra wrote:
> On Tue, 2011-11-15 at 23:28 -0800, Paul Turner wrote:
>> On 11/15/2011 10:16 AM, Il Han wrote:
>>> The prototype has to agree with the definition.
>>> Add the inline keyword to the prototype also
>>>
>>
>> Hmm... this would then cause the prototypes to disagree in the
>> !CONFIG_CFS_BANDWIDTH case.
>
> I'm very sure I've compiled a lot of kernels yesterday with various
> permutations including FAIR_GROUP&&  !CFS_BANDWIDTH and I'm also very
> sure I haven't actually seen any complaints like this.
>
> It this some new fangled GCC 'feature'? I'm currently still on 4.5 which
> admittedly is somewhat stale.

gcc (even 4.6) won't give warnings either way about the inline attribute on a 
forward declaration not matching in either direction.  I would imagine this was 
found by code-inspection.

I was only pointing out with this we have:

#if CONFIG_CFS_BANDWIDTH
static __always_inline xxx() { stuff; } [1]
#else
static xxx() {} [2]
#endif

And that by only changing the pre-declaration to match [1] it now similarly 
(silently) would not match [2] in the !CONFIG case.

- Paul