From mboxrd@z Thu Jan 1 00:00:00 1970 From: Punit Agrawal Subject: [RFC PATCH 2/2] mm/hugetlb: Support swap entries in huge_pte_offset() Date: Mon, 24 Jul 2017 18:33:18 +0100 Message-ID: <20170724173318.966-3-punit.agrawal@arm.com> References: <20170724173318.966-1-punit.agrawal@arm.com> Return-path: In-Reply-To: <20170724173318.966-1-punit.agrawal@arm.com> Sender: owner-linux-mm@kvack.org To: Andrew Morton Cc: Punit Agrawal , Naoya Horiguchi , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, steve.capper@arm.com, will.deacon@arm.com, catalin.marinas@arm.com, kirill.shutemov@linux.intel.com, Michal Hocko , Mike Kravetz List-Id: linux-arch.vger.kernel.org Although huge_pte_offset() returns NULL when encountering swap page table entries, the callers of huge_pte_offset() correctly handling swap entries. Add support to the huge_pte_offset() to return the swap entries when it encounters them during the page table walks. Also update the function documentation to explicitly state this behaviour. This is to help clarify expectations for architecture specific implementations of huge_pte_offset(). Signed-off-by: Punit Agrawal --- mm/hugetlb.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 686eb6fa9eb1..72dd1139a8e4 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -4607,8 +4607,8 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, * huge_pte_offset() - Walk the page table to resolve the hugepage * entry at address @addr * - * Return: Pointer to page table entry (PUD or PMD) for address @addr - * or NULL if the entry is not present. + * Return: Pointer to page table or swap entry (PUD or PMD) for address @addr + * or NULL if the entry is p*d_none(). */ pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr, unsigned long sz) @@ -4626,15 +4626,17 @@ pte_t *huge_pte_offset(struct mm_struct *mm, return NULL; pud = pud_offset(p4d, addr); - if (!pud_present(*pud)) + if (pud_none(*pud)) return NULL; - if (pud_huge(*pud)) + /* hugepage or swap? */ + if (pud_huge(*pud) || !pud_present(*pud)) return (pte_t *)pud; pmd = pmd_offset(pud, addr); - if (!pmd_present(*pmd)) + if (pmd_none(*pmd)) return NULL; - if (pmd_huge(*pmd)) + /* hugepage or swap? */ + if (pmd_huge(*pmd) || !pmd_present(*pmd)) return (pte_t *) pmd; return NULL; -- 2.11.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:35840 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932936AbdGXRd7 (ORCPT ); Mon, 24 Jul 2017 13:33:59 -0400 From: Punit Agrawal Subject: [RFC PATCH 2/2] mm/hugetlb: Support swap entries in huge_pte_offset() Date: Mon, 24 Jul 2017 18:33:18 +0100 Message-ID: <20170724173318.966-3-punit.agrawal@arm.com> In-Reply-To: <20170724173318.966-1-punit.agrawal@arm.com> References: <20170724173318.966-1-punit.agrawal@arm.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Andrew Morton Cc: Punit Agrawal , Naoya Horiguchi , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, steve.capper@arm.com, will.deacon@arm.com, catalin.marinas@arm.com, kirill.shutemov@linux.intel.com, Michal Hocko , Mike Kravetz Message-ID: <20170724173318.7kGKsPzn1_W8JtOUutwa6oKio3QuBGoIthTRlruc1X8@z> Although huge_pte_offset() returns NULL when encountering swap page table entries, the callers of huge_pte_offset() correctly handling swap entries. Add support to the huge_pte_offset() to return the swap entries when it encounters them during the page table walks. Also update the function documentation to explicitly state this behaviour. This is to help clarify expectations for architecture specific implementations of huge_pte_offset(). Signed-off-by: Punit Agrawal --- mm/hugetlb.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 686eb6fa9eb1..72dd1139a8e4 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -4607,8 +4607,8 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, * huge_pte_offset() - Walk the page table to resolve the hugepage * entry at address @addr * - * Return: Pointer to page table entry (PUD or PMD) for address @addr - * or NULL if the entry is not present. + * Return: Pointer to page table or swap entry (PUD or PMD) for address @addr + * or NULL if the entry is p*d_none(). */ pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr, unsigned long sz) @@ -4626,15 +4626,17 @@ pte_t *huge_pte_offset(struct mm_struct *mm, return NULL; pud = pud_offset(p4d, addr); - if (!pud_present(*pud)) + if (pud_none(*pud)) return NULL; - if (pud_huge(*pud)) + /* hugepage or swap? */ + if (pud_huge(*pud) || !pud_present(*pud)) return (pte_t *)pud; pmd = pmd_offset(pud, addr); - if (!pmd_present(*pmd)) + if (pmd_none(*pmd)) return NULL; - if (pmd_huge(*pmd)) + /* hugepage or swap? */ + if (pmd_huge(*pmd) || !pmd_present(*pmd)) return (pte_t *) pmd; return NULL; -- 2.11.0