Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932992AbaJVLJn (ORCPT ); Wed, 22 Oct 2014 07:09:43 -0400 Received: from e06smtp13.uk.ibm.com ([195.75.94.109]:51131 "EHLO e06smtp13.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932932AbaJVLJi (ORCPT ); Wed, 22 Oct 2014 07:09:38 -0400 From: Dominik Dingel To: Andrew Morton , linux-mm@kvack.org, Mel Gorman , Michal Hocko , Paolo Bonzini , Dave Hansen , Rik van Riel Cc: Andrea Arcangeli , Andy Lutomirski , "Aneesh Kumar K.V" , Bob Liu , Christian Borntraeger , Cornelia Huck , Gleb Natapov , Heiko Carstens , "H. Peter Anvin" , Hugh Dickins , Ingo Molnar , Jianyu Zhan , Johannes Weiner , "Kirill A. Shutemov" , kvm@vger.kernel.org, linux390@de.ibm.com, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, Martin Schwidefsky , Peter Zijlstra , Sasha Levin , Dominik Dingel Subject: [PATCH 2/4] mm: introduce mm_forbids_zeropage function Date: Wed, 22 Oct 2014 13:09:28 +0200 Message-Id: <1413976170-42501-3-git-send-email-dingel@linux.vnet.ibm.com> X-Mailer: git-send-email 1.8.5.5 In-Reply-To: <1413976170-42501-1-git-send-email-dingel@linux.vnet.ibm.com> References: <1413976170-42501-1-git-send-email-dingel@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14102211-0013-0000-0000-0000018F6DAA Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add a new function stub to allow architectures to disable for an mm_structthe backing of non-present, anonymous pages with read-only empty zero pages. Signed-off-by: Dominik Dingel --- include/linux/mm.h | 4 ++++ mm/huge_memory.c | 2 +- mm/memory.c | 2 +- 3 files changed, 6 insertions(+), 2 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index cd33ae2..0a2022e 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -56,6 +56,10 @@ extern int sysctl_legacy_va_layout; #define __pa_symbol(x) __pa(RELOC_HIDE((unsigned long)(x), 0)) #endif +#ifndef mm_forbids_zeropage +#define mm_forbids_zeropage(X) (0) +#endif + extern unsigned long sysctl_user_reserve_kbytes; extern unsigned long sysctl_admin_reserve_kbytes; diff --git a/mm/huge_memory.c b/mm/huge_memory.c index de98415..357a381 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -805,7 +805,7 @@ int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, return VM_FAULT_OOM; if (unlikely(khugepaged_enter(vma, vma->vm_flags))) return VM_FAULT_OOM; - if (!(flags & FAULT_FLAG_WRITE) && + if (!(flags & FAULT_FLAG_WRITE) && !mm_forbids_zeropage(mm) && transparent_hugepage_use_zero_page()) { spinlock_t *ptl; pgtable_t pgtable; diff --git a/mm/memory.c b/mm/memory.c index 64f82aa..f275a9d 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2640,7 +2640,7 @@ static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, return VM_FAULT_SIGBUS; /* Use the zero-page for reads */ - if (!(flags & FAULT_FLAG_WRITE)) { + if (!(flags & FAULT_FLAG_WRITE) && !mm_forbids_zeropage(mm)) { entry = pte_mkspecial(pfn_pte(my_zero_pfn(address), vma->vm_page_prot)); page_table = pte_offset_map_lock(mm, pmd, address, &ptl); -- 1.8.5.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/