Re: [PATCH V4 11/18] powerpc/mm: Hugetlbfs is book3s_64 and fsl_book3e (32 or 64)

Paul Mackerras [off-list ref] writes:

On Tue, Feb 23, 2016 at 10:18:13AM +0530, Aneesh Kumar K.V wrote:

quoted

We move large part of fsl related code to hugetlbpage-book3e.c.
Only code movement. This also avoid #ifdef in the code.

Eventhough we allow hugetlbfs only for book3s 64 and fsl book3e, I am
still retaining the #ifdef in hugetlbpage-book3e.c. It looks like there
was an attempt to support hugetlbfs on other non hash platforms. I
didn't want to loose that work.

Well... that stuff is always in git.  It seems that the only 64-bit
non-Freescale Book E platform we had was A2, and that code got deleted
because the product was never released.

You get rid of some but not all of the ifdefs in hugetlbpage-book3e.c,
and the result is a bit confusing (see below).  In fact that file will
only get compiled for Freescale Book E processors, because the
Makefile has an ifdef on HUGETLB_PAGE, which ultimately depends on
SYS_SUPPORTS_HUGETLBFS, which is only set for Freescale Book E and
64-bit server.

However, a larger question is why this cleanup is necessary for
preparing for the radix tree.  Nothing in the following patches in
this series seems to depend on this patch.

I am putting together radix changes on top of the PTE rewrite patch
series and I thought of retaining most of the code cleanup because
that makes the applying further patches easy. This was mostly needed so
that we can update hugetlb for radix easily. 

https://github.com/kvaneesh/linux/commit/31e7c351e8a2fd9e347f9837e9e765b648786e7a

I haven't got that change on top of my current tree yet. IMHO I
found the cleanup easier. I agree that I was focusing mostly on book3s
and was trying to keep nonhash as close to the original version. 

I can move this cleanup as a separate series if it is confusing to look
at it related to radix preparation. If the cleanup is not helping, let
me know, we can add them later along with rest of radix changes if
needed.

The most important change in this series that we need to get merged in
the next merge window is the 4 level page table. Rest of the patches are
all code movement/cleanups.

-aneesh