From ff20c2e0acc5ad7e27c68592ade135efee399549 Mon Sep 17 00:00:00 2001 From: Kirill A. Shutemov Date: Tue, 1 Mar 2016 09:45:14 +0530 Subject: mm: Some arch may want to use HPAGE_PMD related values as variables With next generation power processor, we are having a new mmu model [1] that require us to maintain a different linux page table format. Inorder to support both current and future ppc64 systems with a single kernel we need to make sure kernel can select between different page table format at runtime. With the new MMU (radix MMU) added, we will have two different pmd hugepage size 16MB for hash model and 2MB for Radix model. Hence make HPAGE_PMD related values as a variable. Actual conversion of HPAGE_PMD to a variable for ppc64 happens in a followup patch. [1] http://ibm.biz/power-isa3 (Needs registration). Signed-off-by: Kirill A. Shutemov Signed-off-by: Aneesh Kumar K.V Signed-off-by: Michael Ellerman --- mm/huge_memory.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) (limited to 'mm/huge_memory.c') diff --git a/mm/huge_memory.c b/mm/huge_memory.c index aea8f7a42df9..36c22a89df61 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -83,7 +83,7 @@ unsigned long transparent_hugepage_flags __read_mostly = (1<= MAX_ORDER); + /* + * we use page->mapping and page->index in second tail page + * as list_head: assuming THP order >= 2 + */ + MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER < 2); + err = hugepage_init_sysfs(&hugepage_kobj); if (err) goto err_sysfs; @@ -764,7 +776,6 @@ void prep_transhuge_page(struct page *page) * we use page->mapping and page->indexlru in second tail page * as list_head: assuming THP order >= 2 */ - BUILD_BUG_ON(HPAGE_PMD_ORDER < 2); INIT_LIST_HEAD(page_deferred_list(page)); set_compound_page_dtor(page, TRANSHUGE_PAGE_DTOR); -- cgit v1.2.3-55-g7522