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 71450C7618F for ; Thu, 18 Jul 2019 16:36:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4F477208C0 for ; Thu, 18 Jul 2019 16:36:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731930AbfGRQgF (ORCPT ); Thu, 18 Jul 2019 12:36:05 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:36432 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727780AbfGRQgE (ORCPT ); Thu, 18 Jul 2019 12:36:04 -0400 Received: by atrey.karlin.mff.cuni.cz (Postfix, from userid 512) id 262EE8029D; Thu, 18 Jul 2019 18:35:51 +0200 (CEST) Date: Thu, 18 Jul 2019 18:36:01 +0200 From: Pavel Machek To: Dan Williams Cc: Balbir Singh , =?iso-8859-1?B?Suly9G1l?= Glisse , Evgeny Baskakov , John Hubbard , Mark Hairgrove , Sherry Cheung , Subhash Gutti , Aneesh Kumar KV , Benjamin Herrenschmidt , David Nellans , Johannes Weiner , "Kirill A. Shutemov" , Michal Hocko , "Paul E. McKenney" , Ross Zwisler , Vladimir Davydov , Bob Liu , "akpm@linux-foundation.org" , Linus Torvalds , kernel list Subject: Re: HMM_MIRROR has less than useful help text Message-ID: <20190718163601.GA21502@amd> References: <20190717074124.GA21617@amd> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="vkogqOf2sHV7VnPd" Content-Disposition: inline In-Reply-To: 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 --vkogqOf2sHV7VnPd Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu 2019-07-18 07:25:42, Dan Williams wrote: > On Thu, Jul 18, 2019 at 4:04 AM Balbir Singh wrot= e: > > > > On Wed, Jul 17, 2019 at 5:41 PM Pavel Machek wrote: > > > > > > Hi! > > > > > > Commit c0b124054f9e42eb6da545a10fe9122a7d7c3f72 has very nice commit > > > message, explaining what HMM_MIRROR is and when it is > > > needed. Unfortunately, it did not make it into Kconfig help: > > > > > > CONFIG_HMM_MIRROR: > > > > > > Select HMM_MIRROR if you want to mirror range of the CPU page table 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. > > > > > > Could that be fixed? > > > > > > This is key information for me: > > > > > > # This is a heterogeneous memory management (HMM) process address spa= ce > > > # mirroring. > > > # This is useful for NVidia GPU >=3D Pascal, Mellanox IB >=3D mlx5 an= d more > > > # hardware in the future. > > > > > > > That seems like a reasonable request >=20 > Hi Pavel, care to send a patch? I hoped patch author would fix up their code. I'm not HMM expert, he should be... Pavel --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --vkogqOf2sHV7VnPd Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAl0wn/EACgkQMOfwapXb+vLB6ACeLmMyj948TuYUlFIoTfib+UuC 2KwAn3SFfrNn/UFu/9H/1W7LWAGPUp1U =54UH -----END PGP SIGNATURE----- --vkogqOf2sHV7VnPd--