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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 B33A9C35669 for ; Sat, 22 Feb 2020 03:42:44 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 65CB020707 for ; Sat, 22 Feb 2020 03:42:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="L7r/a3iL" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 65CB020707 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=nvidia.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 1DBF06B000A; Fri, 21 Feb 2020 22:42:44 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 166856B000C; Fri, 21 Feb 2020 22:42:44 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 055436B000D; Fri, 21 Feb 2020 22:42:43 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0188.hostedemail.com [216.40.44.188]) by kanga.kvack.org (Postfix) with ESMTP id E11DE6B000A for ; Fri, 21 Feb 2020 22:42:43 -0500 (EST) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 9E1E1180AD804 for ; Sat, 22 Feb 2020 03:42:43 +0000 (UTC) X-FDA: 76516366206.24.brass40_8c23fd9d86529 X-HE-Tag: brass40_8c23fd9d86529 X-Filterd-Recvd-Size: 3585 Received: from hqnvemgate25.nvidia.com (hqnvemgate25.nvidia.com [216.228.121.64]) by imf01.hostedemail.com (Postfix) with ESMTP for ; Sat, 22 Feb 2020 03:42:42 +0000 (UTC) Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate25.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Fri, 21 Feb 2020 19:42:07 -0800 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Fri, 21 Feb 2020 19:42:41 -0800 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Fri, 21 Feb 2020 19:42:41 -0800 Received: from [10.110.48.28] (10.124.1.5) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Sat, 22 Feb 2020 03:42:41 +0000 From: John Hubbard Subject: [LSF/MM/BPF ATTEND]: gup+dma, struct-less page support for devices, THP migration, memory hinting X-Nvconfidentiality: public To: , Linux-MM , linux-fsdevel Message-ID: <9fe958f2-5a96-9f0c-7eeb-76123d1bfca0@nvidia.com> Date: Fri, 21 Feb 2020 19:42:40 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 X-Originating-IP: [10.124.1.5] X-ClientProxiedBy: HQMAIL111.nvidia.com (172.20.187.18) To HQMAIL107.nvidia.com (172.20.187.13) Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1582342927; bh=TbXBPrLq5M8QW+k0aPKocsr/O7hXql8xggisjzzib1E=; h=X-PGP-Universal:From:Subject:X-Nvconfidentiality:To:Message-ID: Date:User-Agent:MIME-Version:X-Originating-IP:X-ClientProxiedBy: Content-Type:Content-Language:Content-Transfer-Encoding; b=L7r/a3iL03hB1G+3mPIDsbLeN5tuhkX9kXcnZwVisTq6CQ5IJf5PkKyCRk/splsEy VRNw4260DTAzVXC4b5IdFtXNgp8bueXwlWlFcr/XTUWlji3VQhy/c8/3P+IewAaakH FrKyPQrWU6aSFLgSa8+LyBc7JNmqhFGUBVI3BIVSWMBvwAtuWxXGedWU3oCC8I1RYw P3Pzb+bkO575ITDyDMZYjzaRkgu4iy7o7NVRMehy54g8ANh23i3MolHOXvdrEPd9v5 5OP7TwiDnGcUtSmKDu1pbcNksA2QphPlZGdPC51za9GgPupwbBHoesjHm9PbGH67dI wUN7oQ2dahvGg== 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: Hi, I'm interested in several areas: * Next steps for the gup/dma work: pin_user_pages*() and related APIs. I'm pretty sure Jan Kara is going to propose that as a TOPIC, but if not, it's fine for the hallway and after hours discussion track. * GPU-centric memory management interests: * The topic areas that Jerome brought up are really important to me: Generic page protection, especially. Without those (or some other clever solution that maybe someone will dream up) there is no way to support atomic operations on memory that the CPU and GPU might both have mapped. * Peer-to-peer RDMA/migration * Representing device memory. (Maybe this means without struct pages.) * THP: modern GPUs love-love-love huge pages, and THP seems like The Way. So all things that make THP work better, especially THP migration, are of interest here. * Memory hinting and other ways of solving the problem of what to do upon a page fault (CPU or GPU page fault, actually): migrate? migrate peer to peer? What should map to where? Slightly richer information would help. This can easily be answered with device drivers and custom allocators, but for NUMA memory (malloc/mmap) it's still not all there. thanks, -- John Hubbard NVIDIA