Re: [RFC 5/9] powerpc/mm: Split huge_pte_offset function for BOOK3S 64K

From: Dave Hansen
Date: Wed Mar 09 2016 - 17:57:40 EST

On 03/09/2016 04:10 AM, Anshuman Khandual wrote:
> Currently the 'huge_pte_offset' function has only one version for
> all the configuations and platforms. This change splits the function
> into two versions, one for 64K page size based BOOK3S implementation
> and the other one for everything else. This change is also one of the
> prerequisites towards enabling GENERAL_HUGETLB implementation for
> BOOK3S 64K based huge pages.

I think there's a bit of background missing here for random folks on
linux-mm to make sense of these patches.

What is BOOK3S and what does it mean for these patches? Why is its 64K
page size implementation different than all the others? Is there a 4K
page size BOOK3S?