From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f197.google.com (mail-pf0-f197.google.com [209.85.192.197]) by kanga.kvack.org (Postfix) with ESMTP id 1FE0D6B0279 for ; Fri, 7 Jul 2017 04:47:01 -0400 (EDT) Received: by mail-pf0-f197.google.com with SMTP id c12so26657924pfj.12 for ; Fri, 07 Jul 2017 01:47:01 -0700 (PDT) Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com. [148.163.156.1]) by mx.google.com with ESMTPS id f17si1773938pfd.162.2017.07.07.01.47.00 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 07 Jul 2017 01:47:00 -0700 (PDT) Received: from pps.filterd (m0098396.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v678iEhg142066 for ; Fri, 7 Jul 2017 04:46:59 -0400 Received: from e23smtp08.au.ibm.com (e23smtp08.au.ibm.com [202.81.31.141]) by mx0a-001b2d01.pphosted.com with ESMTP id 2bj1a6jx92-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Fri, 07 Jul 2017 04:46:59 -0400 Received: from localhost by e23smtp08.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 7 Jul 2017 18:46:56 +1000 Received: from d23av05.au.ibm.com (d23av05.au.ibm.com [9.190.234.119]) by d23relay08.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id v678klYC10355006 for ; Fri, 7 Jul 2017 18:46:55 +1000 Received: from d23av05.au.ibm.com (localhost [127.0.0.1]) by d23av05.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id v678kMKU016690 for ; Fri, 7 Jul 2017 18:46:23 +1000 Subject: Re: [RFC PATCH 1/1] mm/mremap: add MREMAP_MIRROR flag for existing mirroring functionality References: <1499357846-7481-1-git-send-email-mike.kravetz@oracle.com> <1499357846-7481-2-git-send-email-mike.kravetz@oracle.com> From: Anshuman Khandual Date: Fri, 7 Jul 2017 14:15:58 +0530 MIME-Version: 1.0 In-Reply-To: <1499357846-7481-2-git-send-email-mike.kravetz@oracle.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Message-Id: Sender: owner-linux-mm@kvack.org List-ID: To: Mike Kravetz , linux-mm@kvack.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Andrew Morton , Andrea Arcangeli , Michal Hocko , Aaron Lu , "Kirill A . Shutemov" On 07/06/2017 09:47 PM, Mike Kravetz wrote: > The mremap system call has the ability to 'mirror' parts of an existing > mapping. To do so, it creates a new mapping that maps the same pages as > the original mapping, just at a different virtual address. This > functionality has existed since at least the 2.6 kernel. > > This patch simply adds a new flag to mremap which will make this > functionality part of the API. It maintains backward compatibility with > the existing way of requesting mirroring (old_size == 0). > > If this new MREMAP_MIRROR flag is specified, then new_size must equal > old_size. In addition, the MREMAP_MAYMOVE flag must be specified. Yeah it all looks good. But why is this requirement that if MREMAP_MAYMOVE is specified then old_size and new_size must be equal. -- 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