From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 59E4EC10F13 for ; Thu, 11 Apr 2019 23:14:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 22F4D20850 for ; Thu, 11 Apr 2019 23:14:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726748AbfDKXOy (ORCPT ); Thu, 11 Apr 2019 19:14:54 -0400 Received: from mail105.syd.optusnet.com.au ([211.29.132.249]:59864 "EHLO mail105.syd.optusnet.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726646AbfDKXOy (ORCPT ); Thu, 11 Apr 2019 19:14:54 -0400 Received: from dread.disaster.area (pa49-195-160-97.pa.nsw.optusnet.com.au [49.195.160.97]) by mail105.syd.optusnet.com.au (Postfix) with ESMTPS id 9F97C105E6F9; Fri, 12 Apr 2019 09:14:44 +1000 (AEST) Received: from dave by dread.disaster.area with local (Exim 4.92) (envelope-from ) id 1hEiu3-0008Sw-S5; Fri, 12 Apr 2019 09:14:43 +1000 Date: Fri, 12 Apr 2019 09:14:43 +1000 From: Dave Chinner To: jglisse@redhat.com Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, linux-mm@kvack.org, John Hubbard , Jan Kara , Dan Williams , Alexander Viro , Johannes Thumshirn , Christoph Hellwig , Jens Axboe , Ming Lei , Jason Gunthorpe , Matthew Wilcox , Ernesto A =?iso-8859-1?Q?=2E_Fern=E1ndez?= , Jeff Moyer Subject: Re: [PATCH v1 12/15] fs/direct-io: keep track of wether a page is coming from GUP or not Message-ID: <20190411231443.GD1695@dread.disaster.area> References: <20190411210834.4105-1-jglisse@redhat.com> <20190411210834.4105-13-jglisse@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20190411210834.4105-13-jglisse@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Optus-CM-Score: 0 X-Optus-CM-Analysis: v=2.2 cv=UJetJGXy c=1 sm=1 tr=0 cx=a_idp_d a=EHa8gIBQe3daEtuMEU8ptg==:117 a=EHa8gIBQe3daEtuMEU8ptg==:17 a=jpOVt7BSZ2e4Z31A5e1TngXxSK0=:19 a=8nJEP1OIZ-IA:10 a=oexKYjalfGEA:10 a=20KFwNOVAAAA:8 a=7-415B0cAAAA:8 a=eWkzej_naR1Ak5NVtaAA:9 a=wPNLvfGTeEIA:10 a=biEYGPWJfzWAr4FL6Ov7:22 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Thu, Apr 11, 2019 at 05:08:31PM -0400, jglisse@redhat.com wrote: > From: Jérôme Glisse > > We want to keep track of how we got a reference on page when doing DIO, > ie wether the page was reference through GUP (get_user_page*) or not. > For that this patch rework the way page reference is taken and handed > over between DIO code and BIO. Instead of taking a reference for page > that have been successfuly added to a BIO we just steal the reference > we have when we lookup the page (either through GUP or for ZERO_PAGE). > > So this patch keep track of wether the reference has been stolen by the > BIO or not. This avoids a bunch of get_page()/put_page() so this limit > the number of atomic operations. Is the asme set of changes appropriate for the fs/iomap.c direct IO path (i.e. XFS)? -Dave. -- Dave Chinner david@fromorbit.com