Re: Folding _PAGE_PWT into _PAGE_PCD (was Re: unify pagetable accessorspatch causes double fault II)

[Jeremy Fitzhardinge]

Andi Kleen wrote:
> > BTW, I just noticed that _PAGE_PWT has been folded into _PAGE_PCD.  This 
> > seems like a really bad idea to me, since it breaks the rule that 
> > _PAGE_X == 1 << _PAGE_BIT_X.  I can't think of a specific place where 
> > this would cause problems, but this kind of non-uniformity always ends 
> > up biting someone in the arse.
> >     
>
> Agreed that it's a bad idea.
>
>   
> > I think having a specific _PAGE_NOCACHE which combines these bits is a 
> > better approach.
> >     
>
> CPA series adds that already
>
> +/* Needs special handling for large pages */
> +#define _PAGE_CACHE     (_PAGE_PCD|_PAGE_PWT|_PAGE_PAT)
>   

Good, but isn't the name _PAGE_CACHE misleading?  Or does it mean 
something else in the context of PAT?

   J
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