Re: [PATCH] x86: fully honor "nolapic" (take 2)

From: Jan Beulich
Date: Fri Jan 16 2009 - 09:09:28 EST


>>> Ingo Molnar <mingo@xxxxxxx> 16.01.09 14:58 >>>
>
>* Jan Beulich <jbeulich@xxxxxxxxxx> wrote:
>
>> >>> Ingo Molnar <mingo@xxxxxxx> 16.01.09 14:42 >>>
>> >
>> >* Jan Beulich <jbeulich@xxxxxxxxxx> wrote:
>> >
>> >> >>> Ingo Molnar <mingo@xxxxxxx> 16.01.09 13:45 >>>
>> >> >
>> >> >* Jan Beulich <jbeulich@xxxxxxxxxx> wrote:
>> >> >
>> >> >> + if (disable_apic) {
>> >> >> +#ifdef CONFIG_X86_IO_APIC
>> >> >> + disable_ioapic_setup();
>> >> >> +#endif
>> >> >> + return;
>> >> >> + }
>> >> >
>> >> > Shouldnt that #ifdef be avoided by always providing the function -
>> >> > just it is a NOP inline in the !CONFIG_X86_IO_APIC case?
>> >>
>> >> That would make for a much bigger patch, since the io_apic.h doesn't
>> >> (and imo shouldn't) be included without that config option.
>> >
>> >But we are using io-apic functionality in that file, so we should include
>> >io_apic.h, right?
>>
>> I don't generally (i.e. when !X86_IO_APIC) think so - anything accessing
>> stuff from io_apic.c is guarded by a similar #ifdef.
>
>and wrongly so - it proliferates ugly #ifdefs and sets us up for build
>failures like that. Developers cannot be expected to keep every build
>option in mind - we should provide an as homogenic and kconfig-invariant
>environment as possible.

I mostly agree here, but think that this ought to be a separate cleanup patch.

Jan

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