From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f169.google.com (mail-wi0-f169.google.com [209.85.212.169]) by kanga.kvack.org (Postfix) with ESMTP id 3F2766B0038 for ; Wed, 22 Oct 2014 15:46:05 -0400 (EDT) Received: by mail-wi0-f169.google.com with SMTP id r20so2167573wiv.2 for ; Wed, 22 Oct 2014 12:46:04 -0700 (PDT) Received: from e06smtp11.uk.ibm.com (e06smtp11.uk.ibm.com. [195.75.94.107]) by mx.google.com with ESMTPS id gn9si98119wib.62.2014.10.22.12.46.02 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 22 Oct 2014 12:46:03 -0700 (PDT) Received: from /spool/local by e06smtp11.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 22 Oct 2014 20:46:02 +0100 Received: from b06cxnps3074.portsmouth.uk.ibm.com (d06relay09.portsmouth.uk.ibm.com [9.149.109.194]) by d06dlp02.portsmouth.uk.ibm.com (Postfix) with ESMTP id 034EA219005C for ; Wed, 22 Oct 2014 20:45:37 +0100 (BST) Received: from d06av04.portsmouth.uk.ibm.com (d06av04.portsmouth.uk.ibm.com [9.149.37.216]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id s9MJk0KS15991114 for ; Wed, 22 Oct 2014 19:46:00 GMT Received: from d06av04.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av04.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s9MJjwIG020080 for ; Wed, 22 Oct 2014 13:46:00 -0600 Date: Wed, 22 Oct 2014 21:45:52 +0200 From: Dominik Dingel Subject: Re: [PATCH 2/4] mm: introduce mm_forbids_zeropage function Message-ID: <20141022214552.0c954692@BR9TG4T3.de.ibm.com> In-Reply-To: <20141022122223.f3bef0f497941fa8e0805dbf@linux-foundation.org> References: <1413976170-42501-1-git-send-email-dingel@linux.vnet.ibm.com> <1413976170-42501-3-git-send-email-dingel@linux.vnet.ibm.com> <20141022122223.f3bef0f497941fa8e0805dbf@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: linux-mm@kvack.org, Mel Gorman , Michal Hocko , Paolo Bonzini , Dave Hansen , Rik van Riel , 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 On Wed, 22 Oct 2014 12:22:23 -0700 Andrew Morton wrote: > On Wed, 22 Oct 2014 13:09:28 +0200 Dominik Dingel wrote: > > > 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. > > > > ... > > > > --- 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 > > Can we document this please? What it does, why it does it. We should > also specify precisely which arch header file is responsible for > defining mm_forbids_zeropage. > I will add a comment like: /* * To prevent common memory management code establishing * a zero page mapping on a read fault. * This function should be implemented within . * s390 does this to prevent multiplexing of hardware bits * related to the physical page in case of virtualization. */ Okay? > -- > 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 > -- 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