From d1402fc708e4c355813e49df6d15bc3466ba5114 Mon Sep 17 00:00:00 2001 From: Logan Gunthorpe Date: Fri, 14 Dec 2018 14:16:53 -0800 Subject: mm: introduce common STRUCT_PAGE_MAX_SHIFT define This define is used by arm64 to calculate the size of the vmemmap region. It is defined as the log2 of the upper bound on the size of a struct page. We move it into mm_types.h so it can be defined properly instead of set and checked with a build bug. This also allows us to use the same define for riscv. Link: http://lkml.kernel.org/r/20181107205433.3875-2-logang@deltatee.com Signed-off-by: Logan Gunthorpe Acked-by: Will Deacon Acked-by: Andrew Morton Acked-by: Ard Biesheuvel Acked-by: Catalin Marinas Cc: Arnd Bergmann Cc: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mm_types.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/linux/mm_types.h') diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 5ed8f6292a53..2c471a2c43fa 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -206,6 +206,11 @@ struct page { #endif } _struct_page_alignment; +/* + * Used for sizing the vmemmap region on some architectures + */ +#define STRUCT_PAGE_MAX_SHIFT (order_base_2(sizeof(struct page))) + #define PAGE_FRAG_CACHE_MAX_SIZE __ALIGN_MASK(32768, ~PAGE_MASK) #define PAGE_FRAG_CACHE_MAX_ORDER get_order(PAGE_FRAG_CACHE_MAX_SIZE) -- cgit v1.2.3-59-g8ed1b