Re: [RFC] Making compound pages mandatory

From: Linus Torvalds
Date: Tue Nov 16 2004 - 21:23:31 EST




On Tue, 16 Nov 2004, David Howells wrote:
>
> Do you have any objection to compound pages being made mandatory, even without
> HUGETLB support?

I haven't really looked into it, so I cannot make an informed decision.
How big is the overhead? And what's the _point_, since we don't seem to
need them normally, but the code is there for people who _do_ need them?

I don't generally like two paths, but quite frankly, I consider the
non-compound case the regular case right now. How expensive does the
compound pages end up being? Is it just one more pointer chase on every
get_page/put_page, or what? Does anybody have numbers for before/after
that are otherwise comparable?

Linus
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