From 5d3a551c28c6669dc43be40d8fafafbc2ec8f42b Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Mon, 8 Oct 2012 16:29:32 -0700 Subject: mm: hugetlb: add arch hook for clearing page flags before entering pool The core page allocator ensures that page flags are zeroed when freeing pages via free_pages_check. A number of architectures (ARM, PPC, MIPS) rely on this property to treat new pages as dirty with respect to the data cache and perform the appropriate flushing before mapping the pages into userspace. This can lead to cache synchronisation problems when using hugepages, since the allocator keeps its own pool of pages above the usual page allocator and does not reset the page flags when freeing a page into the pool. This patch adds a new architecture hook, arch_clear_hugepage_flags, so that architectures which rely on the page flags being in a particular state for fresh allocations can adjust the flags accordingly when a page is freed into the pool. Signed-off-by: Will Deacon Cc: Michal Hocko Reviewed-by: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/powerpc/include/asm/hugetlb.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'arch/powerpc') diff --git a/arch/powerpc/include/asm/hugetlb.h b/arch/powerpc/include/asm/hugetlb.h index dfdb95bc59a5..62e11a32c4c2 100644 --- a/arch/powerpc/include/asm/hugetlb.h +++ b/arch/powerpc/include/asm/hugetlb.h @@ -151,6 +151,10 @@ static inline void arch_release_hugepage(struct page *page) { } +static inline void arch_clear_hugepage_flags(struct page *page) +{ +} + #else /* ! CONFIG_HUGETLB_PAGE */ static inline void flush_hugetlb_page(struct vm_area_struct *vma, unsigned long vmaddr) -- cgit v1.2.3