From f2b79c0d79683d552369bb9a7282c1f0226fc566 Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Tue, 25 Jul 2023 00:37:57 +0530 Subject: powerpc/book3s64/radix: add support for vmemmap optimization for radix With 2M PMD-level mapping, we require 32 struct pages and a single vmemmap page can contain 1024 struct pages (PAGE_SIZE/sizeof(struct page)). Hence with 64K page size, we don't use vmemmap deduplication for PMD-level mapping. [aneesh.kumar@linux.ibm.com: ppc64: don't include radix headers if CONFIG_PPC_RADIX_MMU=n] Link: https://lkml.kernel.org/r/87zg3jw8km.fsf@linux.ibm.com Link: https://lkml.kernel.org/r/20230724190759.483013-12-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V Cc: Catalin Marinas Cc: Christophe Leroy Cc: Dan Williams Cc: Joao Martins Cc: Michael Ellerman Cc: Mike Kravetz Cc: Muchun Song Cc: Nicholas Piggin Cc: Oscar Salvador Cc: Will Deacon Signed-off-by: Andrew Morton --- Documentation/mm/vmemmap_dedup.rst | 1 + 1 file changed, 1 insertion(+) (limited to 'Documentation/mm') diff --git a/Documentation/mm/vmemmap_dedup.rst b/Documentation/mm/vmemmap_dedup.rst index a4b12ff906c4..c573e08b5043 100644 --- a/Documentation/mm/vmemmap_dedup.rst +++ b/Documentation/mm/vmemmap_dedup.rst @@ -210,6 +210,7 @@ the device (altmap). The following page sizes are supported in DAX: PAGE_SIZE (4K on x86_64), PMD_SIZE (2M on x86_64) and PUD_SIZE (1G on x86_64). +For powerpc equivalent details see Documentation/powerpc/vmemmap_dedup.rst The differences with HugeTLB are relatively minor. -- cgit v1.2.3