[PATCH -V7 01/18] mm/THP: HPAGE_SHIFT is not a #define on some arch

[David Gibson]

On Tue, Apr 30, 2013 at 12:21:49PM +1000, David Gibson wrote:
> On Mon, Apr 29, 2013 at 01:07:22AM +0530, Aneesh Kumar K.V wrote:
> > From: "Aneesh Kumar K.V" <aneesh.kumar at linux.vnet.ibm.com>
> > 
> > On archs like powerpc that support different hugepage sizes, HPAGE_SHIFT
> > and other derived values like HPAGE_PMD_ORDER are not constants. So move
> > that to hugepage_init
> 
> These seems to miss the point.  Those variables may be defined in
> terms of HPAGE_SHIFT right now, but that is of itself kind of broken.
> The transparent hugepage mechanism only works if the hugepage size is
> equal to the PMD size - and PMD_SHIFT remains a compile time constant.
> 
> There's no reason having transparent hugepage should force the PMD
> size of hugepage to be the default for other purposes - it should be
> possible to do THP as long as PMD-sized is a possible hugepage size.

Oh, also, I'm pretty sure I said something similar on the last
posting.  Receiving review comments and then ignoring them does not
count as "Reviewed-by"...

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 198 bytes
Desc: Digital signature
URL: <http://lists.ozlabs.org/pipermail/linuxppc-dev/attachments/20130430/5bb0b613/attachment.sig>