[PATCH v2 1/6] mm: Introduce common STRUCT_PAGE_MAX_SHIFT define
From: logang@deltatee.com (Logan Gunthorpe)
Date: 2018-10-15 17:59:12
Also in:
linux-mm, linux-riscv, linux-sh, lkml
Subsystem:
arm64 port (aarch64 architecture), generic include/asm header files, memory management - core, the rest · Maintainers:
Catalin Marinas, Will Deacon, Arnd Bergmann, Andrew Morton, David Hildenbrand, Linus Torvalds
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. Signed-off-by: Logan Gunthorpe <logang@deltatee.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <redacted> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Christoph Hellwig <hch@lst.de> --- arch/arm64/include/asm/memory.h | 9 --------- arch/arm64/mm/init.c | 8 -------- include/asm-generic/fixmap.h | 1 + include/linux/mm_types.h | 5 +++++ 4 files changed, 6 insertions(+), 17 deletions(-)
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index b96442960aea..f0a5c9531e8b 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h@@ -34,15 +34,6 @@ */ #define PCI_IO_SIZE SZ_16M -/* - * Log2 of the upper bound of the size of a struct page. Used for sizing - * the vmemmap region only, does not affect actual memory footprint. - * We don't use sizeof(struct page) directly since taking its size here - * requires its definition to be available at this point in the inclusion - * chain, and it may not be a power of 2 in the first place. - */ -#define STRUCT_PAGE_MAX_SHIFT 6 - /* * VMEMMAP_SIZE - allows the whole linear region to be covered by * a struct page array
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 787e27964ab9..6a0b5c5a61af 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c@@ -615,14 +615,6 @@ void __init mem_init(void) BUILD_BUG_ON(TASK_SIZE_32 > TASK_SIZE_64); #endif -#ifdef CONFIG_SPARSEMEM_VMEMMAP - /* - * Make sure we chose the upper bound of sizeof(struct page) - * correctly when sizing the VMEMMAP array. - */ - BUILD_BUG_ON(sizeof(struct page) > (1 << STRUCT_PAGE_MAX_SHIFT)); -#endif - if (PAGE_SIZE >= 16384 && get_num_physpages() <= 128) { extern int sysctl_overcommit_memory; /*
diff --git a/include/asm-generic/fixmap.h b/include/asm-generic/fixmap.h
index 827e4d3bbc7a..8cc7b09c1bc7 100644
--- a/include/asm-generic/fixmap.h
+++ b/include/asm-generic/fixmap.h@@ -16,6 +16,7 @@ #define __ASM_GENERIC_FIXMAP_H #include <linux/bug.h> +#include <linux/mm_types.h> #define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT)) #define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 5ed8f6292a53..ec8c16d9396b 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 ilog2(roundup_pow_of_two(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)
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2.19.0