Re: [patch 2/3] CONFIG_HIGHPTE vs. sub-page page tables.

[Ingo Molnar <mingo@elte.hu>]

* Andrew Morton <akpm@linux-foundation.org> wrote:

> > > urgh, well, thanks for trying.  If there's significant risk factor 
> > > (or hassle) in fixing the macros then I'd suggest we not do it for 
> > > now - it's a separate project.
> > 
> > I'm still at it. I does make sense to convert the damn macros to 
> > inline functions. The question now is the order of things, the macro 
> > cleanup first or the sub-page page tables first? I would prefer the 
> > sub-page page tables first since that code has been hanging around 
> > in -mm for a while and could go upstream after I regenerated the 
> > patch and test compiled it again. We do need it for KVM and we want 
> > to push our KVM patches for s390 soon.
> 
> I'd suggest do the macro ceanup later.  That's the sort of thing which 
> we can/should trickle through arch maintainers.

note that there are ways to stage even API extensions like adding an 
extra 'struct mm_struct *mm' to macros. It takes a temporary ugliness 
like:

 #define __EXTRA_MM_ARG_DEF			, struct mm_struct *mm
 #define __EXTRA_MM_ARG_VAL(arg)		, (arg)

which converted architectures redefine.

and at the end eliminate these compatibility macros from the core, once 
all arches have converted.

so we _could_ stage even something like this.

	Ingo