Re: [RFC 00/15] x86_64: Optimize percpu accesses

From: Mike Travis
Date: Wed Jul 09 2008 - 17:05:46 EST


Ingo Molnar wrote:
> * Jeremy Fitzhardinge <jeremy@xxxxxxxx> wrote:
>
>>> What is remaining is the task to rename
>>>
>>> pda.Y -> Z
>>>
>>> in order to make variable references the same under both arches.
>>> Presumably the Z is the corresponding 32 bit variable. There are
>>> likely a number of cases where the transformation is trivial if we
>>> just identify the corresponding 32 bit equivalent.
>> Yes, I understand that, but it's still pointless churn. The
>> intermediate step is no improvement over what was there before, and
>> isn't any closer to the desired final result.
>>
>> Once you've made the pda a percpu variable, and redefined all the
>> X_pda macros in terms of x86_X_percpu, then there's no need to touch
>> all the usage sites until you're *actually* going to unify something.
>> Touching them all just because you find "X_pda" unsightly doesn't help
>> anyone. Ideally every site you touch will remove a #ifdef
>> CONFIG_X86_64, or make two as-yet unified pieces of code closer to
>> unification.
>
> that makes sense. Does everyone agree on #1-#2-#3 and then gradual
> elimination of most pda members (without going through an intermediate
> renaming of pda members) being the way to go?
>
> Ingo


This is fine with me... not much more work required to go "all the way"... ;-)
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