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,URIBL_BLOCKED,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 231F8C76188 for ; Fri, 19 Jul 2019 10:52:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 00BAC20873 for ; Fri, 19 Jul 2019 10:52:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727671AbfGSKwn (ORCPT ); Fri, 19 Jul 2019 06:52:43 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:33920 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726239AbfGSKwn (ORCPT ); Fri, 19 Jul 2019 06:52:43 -0400 Received: by atrey.karlin.mff.cuni.cz (Postfix, from userid 512) id AEBEB802EE; Fri, 19 Jul 2019 12:52:28 +0200 (CEST) Date: Fri, 19 Jul 2019 12:52:39 +0200 From: Pavel Machek To: Christoph Hellwig Cc: john.hubbard@gmail.com, SCheung@nvidia.com, akpm@linux-foundation.org, aneesh.kumar@linux.vnet.ibm.com, benh@kernel.crashing.org, bsingharora@gmail.com, dan.j.williams@intel.com, dnellans@nvidia.com, ebaskakov@nvidia.com, hannes@cmpxchg.org, jglisse@redhat.com, jhubbard@nvidia.com, kirill.shutemov@linux.intel.com, linux-kernel@vger.kernel.org, liubo95@huawei.com, mhairgrove@nvidia.com, mhocko@kernel.org, paulmck@linux.vnet.ibm.com, ross.zwisler@linux.intel.com, sgutti@nvidia.com, torvalds@linux-foundation.org, vdavydov.dev@gmail.com, Jason Gunthorpe Subject: Re: [PATCH] mm/Kconfig: additional help text for HMM_MIRROR option Message-ID: <20190719105239.GA10627@amd> References: <20190717074124.GA21617@amd> <20190719013253.17642-1-jhubbard@nvidia.com> <20190719055748.GA29082@infradead.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="liOOAslEiF7prFVr" Content-Disposition: inline In-Reply-To: <20190719055748.GA29082@infradead.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --liOOAslEiF7prFVr Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu 2019-07-18 22:57:48, Christoph Hellwig wrote: > On Thu, Jul 18, 2019 at 06:32:53PM -0700, john.hubbard@gmail.com wrote: > > + HMM_MIRROR provides a way to mirror ranges of the CPU page tables > > + of a process into a device page table. Here, mirror means "keep > > + synchronized". Prerequisites: the device must provide the ability > > + to write-protect its page tables (at PAGE_SIZE granularity), and > > + must be able to recover from the resulting potential page faults. > > + > > + Select HMM_MIRROR if you have hardware that meets the above > > + description. An early, partial list of such hardware is: > > + an NVIDIA GPU >=3D Pascal, Mellanox IB >=3D mlx5, or an AMD GPU. >=20 > Nevermind that the Nvidia support is stagaging and looks rather broken, > there is no Mellanox user of this either at this point. >=20 > But either way this has no business in a common kconfig help. Just > drop the fine grained details and leave it to the overview. I disagree here. This explains what kind of hardware this is for (very new). Partial list does not hurt, and I know that I probably don't need to enable this. How else am I supposed to know if my computer needs page tables synchronized? Pavel --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --liOOAslEiF7prFVr Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAl0xoPcACgkQMOfwapXb+vIiygCgpZIgxcueA5lGweI7pvQKR6l2 oNQAn2gePbpEnABaDspF4wN2+WKGu1GH =y1s7 -----END PGP SIGNATURE----- --liOOAslEiF7prFVr--