From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wg0-f48.google.com (mail-wg0-f48.google.com [74.125.82.48]) by kanga.kvack.org (Postfix) with ESMTP id 5DC726B006E for ; Wed, 22 Oct 2014 04:30:47 -0400 (EDT) Received: by mail-wg0-f48.google.com with SMTP id k14so3102642wgh.7 for ; Wed, 22 Oct 2014 01:30:46 -0700 (PDT) Received: from e06smtp17.uk.ibm.com (e06smtp17.uk.ibm.com. [195.75.94.113]) by mx.google.com with ESMTPS id yw4si17609892wjc.94.2014.10.22.01.30.45 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 22 Oct 2014 01:30:46 -0700 (PDT) Received: from /spool/local by e06smtp17.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 22 Oct 2014 09:30:45 +0100 Received: from b06cxnps3075.portsmouth.uk.ibm.com (d06relay10.portsmouth.uk.ibm.com [9.149.109.195]) by d06dlp03.portsmouth.uk.ibm.com (Postfix) with ESMTP id E4D551B08072 for ; Wed, 22 Oct 2014 09:30:41 +0100 (BST) Received: from d06av09.portsmouth.uk.ibm.com (d06av09.portsmouth.uk.ibm.com [9.149.37.250]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id s9M8UfLW16384308 for ; Wed, 22 Oct 2014 08:30:41 GMT Received: from d06av09.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av09.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s9M8UeP0031412 for ; Wed, 22 Oct 2014 02:30:41 -0600 From: Dominik Dingel Subject: [PATCH 2/4] mm: introduce mm_forbids_zeropage function Date: Wed, 22 Oct 2014 10:30:22 +0200 Message-Id: <1413966624-12447-3-git-send-email-dingel@linux.vnet.ibm.com> In-Reply-To: <1413966624-12447-1-git-send-email-dingel@linux.vnet.ibm.com> References: <1413966624-12447-1-git-send-email-dingel@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: 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" , Konstantin Weitz , 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 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, 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