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=BAYES_00, 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 E71C0C49EA7 for ; Thu, 24 Jun 2021 05:30:54 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4BA41613ED for ; Thu, 24 Jun 2021 05:30:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4BA41613ED 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 35C428D000C; Thu, 24 Jun 2021 01:30:53 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 30D128D0008; Thu, 24 Jun 2021 01:30:53 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1BE928D000C; Thu, 24 Jun 2021 01:30:53 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0100.hostedemail.com [216.40.44.100]) by kanga.kvack.org (Postfix) with ESMTP id CE97E8D0008 for ; Thu, 24 Jun 2021 01:30:52 -0400 (EDT) Received: from smtpin14.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 03965181AEF30 for ; Thu, 24 Jun 2021 05:30:53 +0000 (UTC) X-FDA: 78287493186.14.3E3B7DD Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf19.hostedemail.com (Postfix) with ESMTP id 69AA39001CA2 for ; Thu, 24 Jun 2021 05:30:52 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 244BF68AFE; Thu, 24 Jun 2021 07:30:49 +0200 (CEST) Date: Thu, 24 Jun 2021 07:30:48 +0200 From: Christoph Hellwig To: Felix Kuehling Cc: Theodore Ts'o , Alex Sierra , akpm@linux-foundation.org, linux-mm@kvack.org, rcampbell@nvidia.com, linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, hch@lst.de, jgg@nvidia.com, jglisse@redhat.com Subject: Re: [PATCH v3 0/8] Support DEVICE_GENERIC memory in migrate_vma_* Message-ID: <20210624053048.GB25004@lst.de> References: <20210617151705.15367-1-alex.sierra@amd.com> <905418d1-9099-0ea8-a6e6-84cc8ef3d0b0@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <905418d1-9099-0ea8-a6e6-84cc8ef3d0b0@amd.com> User-Agent: Mutt/1.5.17 (2007-11-01) Authentication-Results: imf19.hostedemail.com; dkim=none; spf=none (imf19.hostedemail.com: domain of hch@lst.de has no SPF policy when checking 213.95.11.211) smtp.mailfrom=hch@lst.de; dmarc=none X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 69AA39001CA2 X-Stat-Signature: owehoqsquixmndxuzpckpnozxb83kgpj X-HE-Tag: 1624512652-363848 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 Wed, Jun 23, 2021 at 05:49:55PM -0400, Felix Kuehling wrote: > For the reference counting changes we could use the dax driver with hmem > and use efi_fake_mem on the kernel command line to create some > DEVICE_GENERIC pages. I'm open to suggestions for good user mode tests to > exercise dax functionality on this type of memory. > > For the migration helper changes we could modify or parametrize > lib/hmm_test.c to create DEVICE_GENERIC pages instead of DEVICE_PRIVATE. > Then run tools/testing/selftests/vm/hmm-tests.c. We'll also need a real in-tree user of the enhanced DEVICE_GENERIC memory. So while the refcounting cleanups early in the series are something I'd really like to see upstream as soon as everything is sorted out, the actual bits that can't only be used by your updated driver should wait for that.