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 0D977C388F2 for ; Fri, 6 Nov 2020 04:08:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9E5142080D for ; Fri, 6 Nov 2020 04:08:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="XUcqFVIT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726082AbgKFEIT (ORCPT ); Thu, 5 Nov 2020 23:08:19 -0500 Received: from hqnvemgate26.nvidia.com ([216.228.121.65]:16193 "EHLO hqnvemgate26.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725616AbgKFEIT (ORCPT ); Thu, 5 Nov 2020 23:08:19 -0500 Received: from hqmail.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate26.nvidia.com (using TLS: TLSv1.2, AES256-SHA) id ; Thu, 05 Nov 2020 20:08:22 -0800 Received: from [10.2.49.167] (10.124.1.5) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Fri, 6 Nov 2020 04:08:11 +0000 Subject: Re: [PATCH v5 05/15] mm/frame-vector: Use FOLL_LONGTERM To: Jason Gunthorpe , Christoph Hellwig , J??r??me Glisse , linux-samsung-soc , Jan Kara , Pawel Osciak , KVM list , Mauro Carvalho Chehab , LKML , DRI Development , Tomasz Figa , Linux MM , Kyungmin Park , "Daniel Vetter" , Andrew Morton , Marek Szyprowski , Dan Williams , Linux ARM , "open list:DMA BUFFER SHARING FRAMEWORK" References: <20201104140023.GQ36674@ziepe.ca> <20201104162125.GA13007@infradead.org> <20201104163758.GA17425@infradead.org> <20201104164119.GA18218@infradead.org> <20201104181708.GU36674@ziepe.ca> <20201105092524.GQ401619@phenom.ffwll.local> <20201105124950.GZ36674@ziepe.ca> From: John Hubbard Message-ID: <7ae3486d-095e-cf4e-6b0f-339d99709996@nvidia.com> Date: Thu, 5 Nov 2020 20:08:10 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: <20201105124950.GZ36674@ziepe.ca> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.124.1.5] X-ClientProxiedBy: HQMAIL105.nvidia.com (172.20.187.12) To HQMAIL107.nvidia.com (172.20.187.13) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1604635702; bh=Zxaf2o6Bf8KCt8GGVyqkabRsYvK65I+alpkY1bpXUj4=; h=Subject:To:References:From:Message-ID:Date:User-Agent: MIME-Version:In-Reply-To:Content-Type:Content-Language: Content-Transfer-Encoding:X-Originating-IP:X-ClientProxiedBy; b=XUcqFVIT6wpyCLo/7MIMA70nfnEAQlMnvxS6BpI49u8niHEonhjOFRr5jpKAiDgSb NruirMHJ0lklnJPVstdxDDpsNeDoRzXNbc/ZwNiwsnyeDHnXN2zye8BykFo4BmM8pn eb+ONcJpKqq41slnim2JQO2fNKWYRjv2D8SW2MtwUNBsIi33cxfub4Kh3D4Qd5ngz+ xrhVX4XmfgwdyAZcB6p78K3Qsl/oPr5iUR4d6pKEmurex3ZAnsYGQ2ya0g2Vdsm1vi TmzogOYW7iQNIRy5mgIxCPwKcT0KL2pFOmPHkECsQklCGjQEZmxD/3b/wK/ZG9ox5k l2KSFxiaOUvow== Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/5/20 4:49 AM, Jason Gunthorpe wrote: > On Thu, Nov 05, 2020 at 10:25:24AM +0100, Daniel Vetter wrote: >>> /* >>> * If we can't determine whether or not a pte is special, then fail immediately >>> * for ptes. Note, we can still pin HugeTLB and THP as these are guaranteed not >>> * to be special. >>> * >>> * For a futex to be placed on a THP tail page, get_futex_key requires a >>> * get_user_pages_fast_only implementation that can pin pages. Thus it's still >>> * useful to have gup_huge_pmd even if we can't operate on ptes. >>> */ >> >> We support hugepage faults in gpu drivers since recently, and I'm not >> seeing a pud_mkhugespecial anywhere. So not sure this works, but probably >> just me missing something again. > > It means ioremap can't create an IO page PUD, it has to be broken up. > > Does ioremap even create anything larger than PTEs? > From my reading, yes. See ioremap_try_huge_pmd(). thanks, -- John Hubbard NVIDIA