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Date: Sun, 18 May 2008 20:13:50 +0200
From: Andi Kleen <andi@firstfloor.org>
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To: Adrian Bunk <bunk@kernel.org>
CC: Jeremy Fitzhardinge <jeremy@goop.org>,
       Thomas Gleixner <tglx@linutronix.de>,
       "Maciej W. Rozycki" <macro@linux-mips.org>,
       Tom Spink <tspink@gmail.com>, Cyrill Gorcunov <gorcunov@gmail.com>,
       Ingo Molnar <mingo@elte.hu>, "H. Peter Anvin" <hpa@zytor.com>,
       LKML <linux-kernel@vger.kernel.org>, Jiri Slaby <jirislaby@gmail.com>,
       Sam Ravnborg <sam@ravnborg.org>
Subject: Re: [RFC] x86: merge nmi_32-64 to nmi.c
References: <20080517192200.GA6914@cvg> <7b9198260805171328u555eec17t3597f3378edbda88@mail.gmail.com> <Pine.LNX.4.55.0805172148380.10067@cliff.in.clinika.pl> <alpine.LFD.1.10.0805172331030.18798@apollo.tec.linutronix.de> <482FD9F2.8080204@goop.org> <20080518180811.GI8140@cs181133002.pp.htv.fi>
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Adrian Bunk wrote:
> On Sun, May 18, 2008 at 08:25:38AM +0100, Jeremy Fitzhardinge wrote:
>> Thomas Gleixner wrote:
>>> Definitely, but we should do it at the Kconfig level which allows us
>>> to have integer defines as well, so we end up with something like:
>>>
>>> static inline unsigned int get_nmi_count(int cpu)
>>> {
>>>       return CONFIG_X86_64 ? cpu_pda(cpu)->__nmi_count : nmi_count(cpu);
>>> }
>>>   
>> Unfortunately that doesn't work because when CONFIG_X86_64 isn't defined  
>> it doesn't expand to 0.  It would be nice if CONFIG_* expanded to 0/1,  
>> but we'd need to change all the #ifdef CONFIG_* to #if CONFIG_*...
> 
> Even more important:
> How do you want to handle kconfig variables set to "m"?
> 
> Expand them to 0.5 ?  ;-)

The whole idea was pretty bad. Ifdefs are not ugly because the syntax
looks ugly, but because it's a semantically ugly construct with bad
maintainability impact.

Trying to put syntactical sugar around that is a doomed exercise. It
will be still ugly, no matter what you do.

-Andi