Messages in this thread | | | Date | Wed, 4 Feb 2009 16:00:37 -0500 | From | wli@movement ... | Subject | Re: FW: [PATCH] powerpc/mm: Export HPAGE_SHIFT |
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On Wed, Feb 04, 2009 at 11:11:22AM -0800, Roland Dreier wrote: > Heh. Looking into the implementation, it seems that I could actually do > PAGE_SIZE << compound_order(page) > directly (since there's no reason to go from size to hstate and back to > size. I don't know all the details of these VM internals, but that > seems to only work on the first (small) page of a giant page? Which > causes problems for what we're trying to do here...
You should be able to find the head of a compound page using the compound_head() inline, so try
PAGE_SIZE << compound_order(compound_head(page))
-- wli
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