Re: [PATCH] kill mm_struct.used_hugetlb

[David Gibson]

On Sat, Jun 26, 2004 at 05:20:20PM +0400, Oleg Nesterov wrote:
> Hello.
> 
> mm_struct.used_hugetlb used to eliminate costly find_vma()
> from follow_page(). Now it is used only in ia64 version of
> follow_huge_addr(). I know nothing about ia64, but this
> REGION_NUMBER() looks simple enough to kill used_hugetlb.
> 
> There is debug version (commented out) of follow_huge_addr()
> in i386 which looks at used_hugetlb, but it can work without
> this check.
> 
> Am i missed somethimg?

Sounds like an excellent idea to me.  The find_vma()s were already
bogus - no-one used the vma returned by hugepage_vma(), except to
check if it was NULL or not.  On all archs, whether the address is
hugepage or not can be determined from the address, either by walking
the pagetables or just by checking the address's range.

-- 
David Gibson			| For every complex problem there is a
david AT gibson.dropbear.id.au	| solution which is simple, neat and
				| wrong.
http://www.ozlabs.org/people/dgibson
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