From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751436AbdBAGh7 (ORCPT ); Wed, 1 Feb 2017 01:37:59 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:37676 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751004AbdBAGh5 (ORCPT ); Wed, 1 Feb 2017 01:37:57 -0500 Date: Wed, 1 Feb 2017 08:37:48 +0200 From: Mike Rapoport To: Andrew Morton Cc: Andrea Arcangeli , "Dr. David Alan Gilbert" , Hillf Danton , Mike Kravetz , Pavel Emelyanov , Linux-MM , LKML Subject: Re: [PATCH v2 2/5] userfaultfd: non-cooperative: add event for memory unmaps References: <1485542673-24387-1-git-send-email-rppt@linux.vnet.ibm.com> <1485542673-24387-3-git-send-email-rppt@linux.vnet.ibm.com> <20170131163928.4e4e05fbd93358d9b937d79b@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170131163928.4e4e05fbd93358d9b937d79b@linux-foundation.org> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 17020106-0036-0000-0000-00000363AD60 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17020106-0037-0000-0000-000014F457EF Message-Id: <20170201063748.GB7921@rapoport-lnx> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-01-31_12:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1612050000 definitions=main-1702010064 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 31, 2017 at 04:39:28PM -0800, Andrew Morton wrote: > On Fri, 27 Jan 2017 20:44:30 +0200 Mike Rapoport wrote: > > > When a non-cooperative userfaultfd monitor copies pages in the background, > > it may encounter regions that were already unmapped. Addition of > > UFFD_EVENT_UNMAP allows the uffd monitor to track precisely changes in the > > virtual memory layout. > > > > Since there might be different uffd contexts for the affected VMAs, we > > first should create a temporary representation for the unmap event for each > > uffd context and then notify them one by one to the appropriate userfault > > file descriptors. > > > > The event notification occurs after the mmap_sem has been released. > > I was going to bug you about not updating > Documentation/vm/userfaultfd.txt but the UFFD_FEATURE flags aren't > documented? I'm going to send the documentation update in the next few days. -- Sincerely yours, Mike.