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=-2.2 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 55B9FC4332B for ; Sat, 21 Mar 2020 08:20:47 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C0AA920658 for ; Sat, 21 Mar 2020 08:20:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C0AA920658 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 12F206B0003; Sat, 21 Mar 2020 04:20:46 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0E0816B0005; Sat, 21 Mar 2020 04:20:46 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F102B6B0007; Sat, 21 Mar 2020 04:20:45 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0128.hostedemail.com [216.40.44.128]) by kanga.kvack.org (Postfix) with ESMTP id D6FF96B0003 for ; Sat, 21 Mar 2020 04:20:45 -0400 (EDT) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 774CE8248068 for ; Sat, 21 Mar 2020 08:20:45 +0000 (UTC) X-FDA: 76618673250.17.oven11_7af63edf23f11 X-HE-Tag: oven11_7af63edf23f11 X-Filterd-Recvd-Size: 2388 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf09.hostedemail.com (Postfix) with ESMTP for ; Sat, 21 Mar 2020 08:20:44 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id C3FCA68AFE; Sat, 21 Mar 2020 09:20:41 +0100 (CET) Date: Sat, 21 Mar 2020 09:20:41 +0100 From: Christoph Hellwig To: Jason Gunthorpe Cc: Ralph Campbell , Christoph Hellwig , Dan Williams , Bharata B Rao , Christian =?iso-8859-1?Q?K=F6nig?= , Ben Skeggs , Jerome Glisse , kvm-ppc@vger.kernel.org, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, nouveau@lists.freedesktop.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH 3/4] mm: simplify device private page handling in hmm_range_fault Message-ID: <20200321082041.GA28613@lst.de> References: <7256f88d-809e-4aba-3c46-a223bd8cc521@nvidia.com> <20200317121536.GQ20941@ziepe.ca> <20200317122445.GA11662@lst.de> <20200317122813.GA11866@lst.de> <20200317124755.GR20941@ziepe.ca> <20200317125955.GA12847@lst.de> <24fca825-3b0f-188f-bcf2-fadcf3a9f05a@nvidia.com> <20200319181716.GK20941@ziepe.ca> <89e33770-a0ab-e1ec-d5e5-535edefd3fd3@nvidia.com> <20200320000345.GO20941@ziepe.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200320000345.GO20941@ziepe.ca> 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 Thu, Mar 19, 2020 at 09:03:45PM -0300, Jason Gunthorpe wrote: > > Should tests enable the feature or the feature enable the test? > > IMHO, if the feature is being compiled into the kernel, that should > > enable the menu item for the test. If the feature isn't selected, > > no need to test it :-) > > I ment if DEVICE_PRIVATE should be a user selectable option at all, or > should it be turned on when a driver like nouveau is selected. I don't think it should be user selectable. This is an implementation detail users can't know about. > Is there some downside to enabling DEVICE_PRIVATE? The option itself adds a little more code to the core kernel, and introduces a few additional branches in core mm code. But more importantly it pulls in the whole pgmap infrastructure.