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=-5.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,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 BF618C55179 for ; Fri, 6 Nov 2020 21:26:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 58BD42087E for ; Fri, 6 Nov 2020 21:26:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="D+Hb3S3I" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728074AbgKFV0x (ORCPT ); Fri, 6 Nov 2020 16:26:53 -0500 Received: from hqnvemgate25.nvidia.com ([216.228.121.64]:12456 "EHLO hqnvemgate25.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725868AbgKFV0x (ORCPT ); Fri, 6 Nov 2020 16:26:53 -0500 Received: from hqmail.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate25.nvidia.com (using TLS: TLSv1.2, AES256-SHA) id ; Fri, 06 Nov 2020 13:26:50 -0800 Received: from rcampbell-dev.nvidia.com (172.20.13.39) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Fri, 6 Nov 2020 21:26:50 +0000 Subject: Re: [PATCH v3 3/6] mm: support THP migration to device private memory To: Christoph Hellwig CC: , , , , "Jerome Glisse" , John Hubbard , "Alistair Popple" , Jason Gunthorpe , Bharata B Rao , Zi Yan , "Kirill A . Shutemov" , Yang Shi , Ben Skeggs , Shuah Khan , "Andrew Morton" References: <20201106005147.20113-1-rcampbell@nvidia.com> <20201106005147.20113-4-rcampbell@nvidia.com> <20201106080322.GE31341@lst.de> From: Ralph Campbell X-Nvconfidentiality: public Message-ID: Date: Fri, 6 Nov 2020 13:26:50 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 In-Reply-To: <20201106080322.GE31341@lst.de> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [172.20.13.39] X-ClientProxiedBy: HQMAIL107.nvidia.com (172.20.187.13) To HQMAIL107.nvidia.com (172.20.187.13) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1604698011; bh=sJlHFFmh1FwR1Swhc5FD4UAS7VszQVSWU413enTyHH4=; h=Subject:To:CC:References:From:X-Nvconfidentiality:Message-ID:Date: User-Agent:MIME-Version:In-Reply-To:Content-Type:Content-Language: Content-Transfer-Encoding:X-Originating-IP:X-ClientProxiedBy; b=D+Hb3S3IoeXUGY43+BDjeVkVQHFWtOWYZpKP/V1fcty+B82xJWfBYCbrNIRLcwd1N xHNxqb4t8k2I+/J1kKnnLsF5xZkxtH+JOsq7sBETw85okpdAVkV2cTPaH+3yzHWUQV 0W2jqDyoUzaJGiP3EhfAPrA37NzlSLU284MbBQY8hK+AY5l7waP/BrPCk4U5cwfu4Q wclHRUc9XPKRGZCTe+xikUB3QYpdfkmjsK9FPg9F2qGpeePz9bHplQ7R35oDaNt1jg VQHbvDCCv9xArzhsLxgy1hTgi/8qcKTrJiwn4j7znBMrdvlFc6JKsA4ta7lEI7Yu/q ldJ63eePyEAMQ== Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/6/20 12:03 AM, Christoph Hellwig wrote: > I hate the extra pin count magic here. IMHO we really need to finish > off the series to get rid of the extra references on the ZONE_DEVICE > pages first. First, thanks for the review comments. I don't like the extra refcount either, that is why I tried to fix that up before resending this series. However, you didn't like me just fixing the refcount only for device private pages and I don't know the dax/pmem code and peer-to-peer PCIe uses of ZONE_DEVICE pages well enough to say how long it will take me to fix all the use cases. So I wanted to make progress on the THP migration code in the mean time.