From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e37.co.us.ibm.com (e37.co.us.ibm.com [32.97.110.158]) (using TLSv1.2 with cipher CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id C947F1A0359 for ; Fri, 19 Feb 2016 03:51:24 +1100 (AEDT) Received: from localhost by e37.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 18 Feb 2016 09:51:22 -0700 Received: from b03cxnp07029.gho.boulder.ibm.com (b03cxnp07029.gho.boulder.ibm.com [9.17.130.16]) by d03dlp03.boulder.ibm.com (Postfix) with ESMTP id C0A6419D803F for ; Thu, 18 Feb 2016 09:39:18 -0700 (MST) Received: from d03av04.boulder.ibm.com (d03av04.boulder.ibm.com [9.17.195.170]) by b03cxnp07029.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u1IGpLZH24641628 for ; Thu, 18 Feb 2016 09:51:21 -0700 Received: from d03av04.boulder.ibm.com (loopback [127.0.0.1]) by d03av04.boulder.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u1IGpIh9014593 for ; Thu, 18 Feb 2016 09:51:20 -0700 From: "Aneesh Kumar K.V" To: benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au Cc: linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, "Kirill A. Shutemov" , "Aneesh Kumar K.V" Subject: [PATCH V3 02/30] mm: Some arch may want to use HPAGE_PMD related values as variables Date: Thu, 18 Feb 2016 22:20:26 +0530 Message-Id: <1455814254-10226-3-git-send-email-aneesh.kumar@linux.vnet.ibm.com> In-Reply-To: <1455814254-10226-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> References: <1455814254-10226-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: "Kirill A. Shutemov" 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 --- arch/powerpc/mm/pgtable_64.c | 7 +++++++ include/linux/bug.h | 9 +++++++++ include/linux/huge_mm.h | 3 --- mm/huge_memory.c | 17 ++++++++++++++--- 4 files changed, 30 insertions(+), 6 deletions(-) diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c index 03f6e72697d0..2ee7bd108f59 100644 --- a/arch/powerpc/mm/pgtable_64.c +++ b/arch/powerpc/mm/pgtable_64.c @@ -818,6 +818,13 @@ pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm, int has_transparent_hugepage(void) { + + BUILD_BUG_ON_MSG((PMD_SHIFT - PAGE_SHIFT) >= MAX_ORDER, + "hugepages can't be allocated by the buddy allocator"); + + BUILD_BUG_ON_MSG((PMD_SHIFT - PAGE_SHIFT) < 2, + "We need more than 2 pages to do deferred thp split"); + if (!mmu_has_feature(MMU_FTR_16M_PAGE)) return 0; /* diff --git a/include/linux/bug.h b/include/linux/bug.h index 7f4818673c41..e51b0709e78d 100644 --- a/include/linux/bug.h +++ b/include/linux/bug.h @@ -20,6 +20,7 @@ struct pt_regs; #define BUILD_BUG_ON_MSG(cond, msg) (0) #define BUILD_BUG_ON(condition) (0) #define BUILD_BUG() (0) +#define MAYBE_BUILD_BUG_ON(cond) (0) #else /* __CHECKER__ */ /* Force a compilation error if a constant expression is not a power of 2 */ @@ -83,6 +84,14 @@ struct pt_regs; */ #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed") +#define MAYBE_BUILD_BUG_ON(cond) \ + do { \ + if (__builtin_constant_p((cond))) \ + BUILD_BUG_ON(cond); \ + else \ + BUG_ON(cond); \ + } while (0) + #endif /* __CHECKER__ */ #ifdef CONFIG_GENERIC_BUG diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index 459fd25b378e..f12513a20a06 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -111,9 +111,6 @@ void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, __split_huge_pmd(__vma, __pmd, __address); \ } while (0) -#if HPAGE_PMD_ORDER >= MAX_ORDER -#error "hugepages can't be allocated by the buddy allocator" -#endif extern int hugepage_madvise(struct vm_area_struct *vma, unsigned long *vm_flags, int advice); extern void vma_adjust_trans_huge(struct vm_area_struct *vma, 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); -- 2.5.0