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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 5AE08C0650F for ; Wed, 14 Aug 2019 07:39:01 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 0252D20843 for ; Wed, 14 Aug 2019 07:39:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0252D20843 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 7A5B86B0007; Wed, 14 Aug 2019 03:39:00 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 72FEF6B0008; Wed, 14 Aug 2019 03:39:00 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5F7BA6B000A; Wed, 14 Aug 2019 03:39:00 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0212.hostedemail.com [216.40.44.212]) by kanga.kvack.org (Postfix) with ESMTP id 37C206B0007 for ; Wed, 14 Aug 2019 03:39:00 -0400 (EDT) Received: from smtpin13.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id E3F6D181AC9AE for ; Wed, 14 Aug 2019 07:38:59 +0000 (UTC) X-FDA: 75820231998.13.talk00_3168871c0df31 X-HE-Tag: talk00_3168871c0df31 X-Filterd-Recvd-Size: 2339 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf14.hostedemail.com (Postfix) with ESMTP for ; Wed, 14 Aug 2019 07:38:59 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 17B9F68B20; Wed, 14 Aug 2019 09:38:55 +0200 (CEST) Date: Wed, 14 Aug 2019 09:38:54 +0200 From: Christoph Hellwig To: Dan Williams Cc: Christoph Hellwig , Jason Gunthorpe , =?iso-8859-1?B?Suly9G1l?= Glisse , Ben Skeggs , Felix Kuehling , Ralph Campbell , "linux-mm@kvack.org" , "nouveau@lists.freedesktop.org" , "dri-devel@lists.freedesktop.org" , "amd-gfx@lists.freedesktop.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 04/15] mm: remove the pgmap field from struct hmm_vma_walk Message-ID: <20190814073854.GA27249@lst.de> References: <20190806160554.14046-1-hch@lst.de> <20190806160554.14046-5-hch@lst.de> <20190807174548.GJ1571@mellanox.com> <20190808065933.GA29382@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Aug 13, 2019 at 06:36:33PM -0700, Dan Williams wrote: > Section alignment constraints somewhat save us here. The only example > I can think of a PMD not containing a uniform pgmap association for > each pte is the case when the pgmap overlaps normal dram, i.e. shares > the same 'struct memory_section' for a given span. Otherwise, distinct > pgmaps arrange to manage their own exclusive sections (and now > subsections as of v5.3). Otherwise the implementation could not > guarantee different mapping lifetimes. > > That said, this seems to want a better mechanism to determine "pfn is > ZONE_DEVICE". So I guess this patch is fine for now, and once you provide a better mechanism we can switch over to it?