Re: [PATCH] x86: fix PAE pmd_bad bootup warning

[Linus Torvalds]

On Tue, 6 May 2008, Hugh Dickins wrote:
>
> Fix Hans' good observation that follow_page() will never find pmd_huge()
> because that would have already failed the pmd_bad test: test pmd_huge in
> between the pmd_none and pmd_bad tests.  Tighten x86's pmd_huge() check?
> No, once it's a hugepage entry, it can get quite far from a good pmd: for
> example, PROT_NONE leaves it with only ACCESSED of the KERN_PGTABLE bits.

I'd much rather have pdm_bad() etc fixed up instead, so that they do a 
more proper test (not thinking that a PSE page is bad, since it clearly 
isn't). And then, make them dependent on DEBUG_VM, because doing the 
proper test will be more expensive.

Hmm?

		Linus
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