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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 B3167C433FF for ; Tue, 30 Jul 2019 05:46:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 92741206E0 for ; Tue, 30 Jul 2019 05:46:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726842AbfG3Fqi (ORCPT ); Tue, 30 Jul 2019 01:46:38 -0400 Received: from verein.lst.de ([213.95.11.211]:47639 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726281AbfG3Fqh (ORCPT ); Tue, 30 Jul 2019 01:46:37 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id ABD1D68AEF; Tue, 30 Jul 2019 07:46:33 +0200 (CEST) Date: Tue, 30 Jul 2019 07:46:33 +0200 From: Christoph Hellwig To: Jerome Glisse Cc: Christoph Hellwig , Jason Gunthorpe , Ben Skeggs , Ralph Campbell , Bharata B Rao , Andrew Morton , linux-mm@kvack.org, nouveau@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 9/9] mm: remove the MIGRATE_PFN_WRITE flag Message-ID: <20190730054633.GA28515@lst.de> References: <20190729142843.22320-1-hch@lst.de> <20190729142843.22320-10-hch@lst.de> <20190729233044.GA7171@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190729233044.GA7171@redhat.com> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 29, 2019 at 07:30:44PM -0400, Jerome Glisse wrote: > On Mon, Jul 29, 2019 at 05:28:43PM +0300, Christoph Hellwig wrote: > > The MIGRATE_PFN_WRITE is only used locally in migrate_vma_collect_pmd, > > where it can be replaced with a simple boolean local variable. > > > > Signed-off-by: Christoph Hellwig > > NAK that flag is useful, for instance a anonymous vma might have > some of its page read only even if the vma has write permission. > > It seems that the code in nouveau is wrong (probably lost that > in various rebase/rework) as this flag should be use to decide > wether to map the device memory with write permission or not. > > I am traveling right now, i will investigate what happened to > nouveau code. We can add it back when needed pretty easily. Much of this has bitrotted way to fast, and the pending ppc kvmhmm code doesn't need it either.