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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS autolearn=unavailable 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 A4830C282DA for ; Tue, 16 Apr 2019 16:12:40 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4D8252087C for ; Tue, 16 Apr 2019 16:12:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="Jytk2YQA" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4D8252087C 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 CFA346B027E; Tue, 16 Apr 2019 12:12:39 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id CA79C6B0287; Tue, 16 Apr 2019 12:12:39 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B70DC6B02A8; Tue, 16 Apr 2019 12:12:39 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-pl1-f198.google.com (mail-pl1-f198.google.com [209.85.214.198]) by kanga.kvack.org (Postfix) with ESMTP id 79D1B6B027E for ; Tue, 16 Apr 2019 12:12:39 -0400 (EDT) Received: by mail-pl1-f198.google.com with SMTP id w9so13655569plz.11 for ; Tue, 16 Apr 2019 09:12:39 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:dkim-signature; bh=0qG+gTlRQll235954BIuhS7cER94zkwgbFGR8CUs9fc=; b=KIpFtF6EfePN1aRZRgVLHsSzAOZY0D4tFhFgqC/KYt4/7SYC5R2z3UyYDm6Qg5EQlb EHNWFzhCsahenWUMGMP3NUDoCeItNxBH10Fc1ks0BJYhsRPwX/32boiWWdNw75pJnNtt LUkjlhKQ17IkOs3DOALovSRWQGYVtbNESV6Badx9MeWVXIYaivzE2He1RoK99ckXgrk0 9Yz4wFgm+NxuzU3XOj7HnPlYSgyGXqeuN7GahsnNwkqq31wYaZw1v2wbW0fxHBJnx8aV x/QEr+igS5xYecq8kLjLcRAxauuc3taR8K4T/v+lnShYUxAyAqk/KeF3zmFy5qdji/6T pqrg== X-Gm-Message-State: APjAAAVo6LL+OFsmmiAqtgFdjoSC6oA5YCpZDOJ/QCBr8zMFaLWfNsz/ STYxmq5zyrsNY/O0q6WaXuxX7p37Rcl7fKzEhf0b81g41NI9TssjEOoGa/RA1LD1tBo7C0ET+av 7duIodPSdK2wyG6ewQ8UPj7DaYLxpHcNNVpxKmcVla2V+8eGa2zlDSr3uigPIVMvcDg== X-Received: by 2002:a63:c54a:: with SMTP id g10mr77023717pgd.71.1555431159062; Tue, 16 Apr 2019 09:12:39 -0700 (PDT) X-Google-Smtp-Source: APXvYqxA4+fq4w0EKUiyXj7TW8QN09IExJ98s5oLL+YmgqZAC0tria6K0sz7DhbZCxgqnzMq6btM X-Received: by 2002:a63:c54a:: with SMTP id g10mr77023660pgd.71.1555431158391; Tue, 16 Apr 2019 09:12:38 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1555431158; cv=none; d=google.com; s=arc-20160816; b=GX0hVQ0a7P1o37HDgladxNq2yasCjeFCOjPs2iJT6fs16xUnvG6wSYwUpVllezUcEV hu7yOkMJcqFavd3TbKy9i8zlcDJjRoQOKUi5MQavfoJdDTXesIbcz3GWeL0dDEDmumqx mAMpV9TBhJ5vCPSN9eQqRq7VcGhra9TGn3Wzbb10XO5sc3D5LYeIGRNQEHShhzZnjXU8 tZGEnDFOR3mSGJujdMudXOJZdY4uIGVZzBJhU/cKSIXOOMxxc2Nxcilt/oSJ9Stbqv3Q L+SHCjDrGqU8JhOPBpkCK4Mzsx7nxnTm91MQ/UUSRRetnsId8Q1sDOeITRUkZlZTMxnY 3VFg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=dkim-signature:mime-version:references:in-reply-to:message-id:date :subject:cc:to:from; bh=0qG+gTlRQll235954BIuhS7cER94zkwgbFGR8CUs9fc=; b=dMwD535TYn7JJrVCeyysh1Qdl0fgIpBfGwKc63mKelqvHbmf/aDWtmpsDwm+MSUy1P lxmAK+by/i8sAdVv0x/sReYEapgTeXqf8e1Z/GQdXp4n3Mk1DwRWb+2o4iu1OKYyCTzX c5RbX/REGWdVQumFAB91BR5gxk6wHYRs4D1rUutaEq24bZ2szh7FVCR6uqCGLfWXW5n1 ai9II6nsi8HDU6LKSmA7SUOZGjJHmKVNZWt9Zf1z3p8mOzL0SN3Y66VlAEAyCZpWAi0v iHCbDtRKQLfnfk5mK9DpJMP8yjzgY+I9jddObAkyf7xCtcNWjxY7pb1k9nb8n4vQ3up9 gW5Q== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@nvidia.com header.s=n1 header.b=Jytk2YQA; spf=pass (google.com: domain of ziy@nvidia.com designates 216.228.121.64 as permitted sender) smtp.mailfrom=ziy@nvidia.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=nvidia.com Received: from hqemgate15.nvidia.com (hqemgate15.nvidia.com. [216.228.121.64]) by mx.google.com with ESMTPS id n7si48833057pff.190.2019.04.16.09.12.38 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 16 Apr 2019 09:12:38 -0700 (PDT) Received-SPF: pass (google.com: domain of ziy@nvidia.com designates 216.228.121.64 as permitted sender) client-ip=216.228.121.64; Authentication-Results: mx.google.com; dkim=pass header.i=@nvidia.com header.s=n1 header.b=Jytk2YQA; spf=pass (google.com: domain of ziy@nvidia.com designates 216.228.121.64 as permitted sender) smtp.mailfrom=ziy@nvidia.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=nvidia.com Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqemgate15.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Tue, 16 Apr 2019 09:12:18 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Tue, 16 Apr 2019 09:12:37 -0700 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Tue, 16 Apr 2019 09:12:37 -0700 Received: from [10.2.164.200] (10.124.1.5) by HQMAIL101.nvidia.com (172.20.187.10) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Tue, 16 Apr 2019 16:12:35 +0000 From: Zi Yan To: Dave Hansen CC: Michal Hocko , Yang Shi , , , , , , , , , , , Subject: Re: [v2 RFC PATCH 0/9] Another Approach to Use PMEM as NUMA Node Date: Tue, 16 Apr 2019 12:12:33 -0400 X-Mailer: MailMate (1.12.4r5622) Message-ID: <027AE219-8C81-47DC-A241-4209C3F656A0@nvidia.com> In-Reply-To: <63514bdd-313b-d42f-e582-f8cb350d0b35@intel.com> References: <1554955019-29472-1-git-send-email-yang.shi@linux.alibaba.com> <20190412084702.GD13373@dhcp22.suse.cz> <20190416074714.GD11561@dhcp22.suse.cz> <960F3918-7D2C-463C-A911-9B62CD7E5D83@nvidia.com> <63514bdd-313b-d42f-e582-f8cb350d0b35@intel.com> MIME-Version: 1.0 X-Originating-IP: [10.124.1.5] X-ClientProxiedBy: HQMAIL104.nvidia.com (172.18.146.11) To HQMAIL101.nvidia.com (172.20.187.10) Content-Type: multipart/signed; boundary="=_MailMate_D57647AE-4DA1-4C9B-AEDB-C24F26D9FE9B_="; micalg=pgp-sha1; protocol="application/pgp-signature" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1555431138; bh=0qG+gTlRQll235954BIuhS7cER94zkwgbFGR8CUs9fc=; h=X-PGP-Universal:From:To:CC:Subject:Date:X-Mailer:Message-ID: In-Reply-To:References:MIME-Version:X-Originating-IP: X-ClientProxiedBy:Content-Type; b=Jytk2YQA8nNJaUP8MgkVSmxdjPUeN9yqd1byaO9hk5gSDhMap8lTMNVOHtgdc1t4A tdw0Ew8E0ETmE3zhpdhDUURSrICP3fjpQnG+16DTk75JmSVaUMlrgKFXdpbRMPo6fu JxU3y7l9J3B8fFCNUgzpHhHUIg3oWhWwmmncSpoStJUmfg87NzfyByFXbbPMG1qJNy 2/JtTWTVQrpqC/6vbuArQjJX4nl2VCGdILF8gjxMdqzEoQBPLkIHfbW0MsbN7tqzp9 YS52pK3hp/dC5Cs8PTS2pnVOuGfmzhZCcsVRg5aV35F/qYhCrNy0apuKbAvguz24wV CFrezbmidOTcw== 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: --=_MailMate_D57647AE-4DA1-4C9B-AEDB-C24F26D9FE9B_= Content-Type: text/plain; markup=markdown On 16 Apr 2019, at 11:55, Dave Hansen wrote: > On 4/16/19 8:33 AM, Zi Yan wrote: >>> We have a reasonable argument that demotion is better than >>> swapping. So, we could say that even if a VMA has a strict NUMA >>> policy, demoting pages mapped there pages still beats swapping >>> them or tossing the page cache. It's doing them a favor to >>> demote them. >> I just wonder whether page migration is always better than >> swapping, since SSD write throughput keeps improving but page >> migration throughput is still low. For example, my machine has a >> SSD with 2GB/s writing throughput but the throughput of 4KB page >> migration is less than 1GB/s, why do we want to use page migration >> for demotion instead of swapping? > > Just because we observe that page migration apparently has lower > throughput today doesn't mean that we should consider it a dead end. I definitely agree. I also want to make the point that we might want to improve page migration as well to show that demotion via page migration will work. Since most of proposed demotion approaches use the same page replacement policy as swapping, if we do not have high-throughput page migration, we might draw false conclusions that demotion is no better than swapping but demotion can actually do much better. :) -- Best Regards, Yan Zi --=_MailMate_D57647AE-4DA1-4C9B-AEDB-C24F26D9FE9B_= Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQJDBAEBAgAtFiEEh7yFAW3gwjwQ4C9anbJR82th+ooFAly1/vEPHHppeUBudmlk aWEuY29tAAoJEJ2yUfNrYfqKz9gP/13w9KgpJ81vf8ZHTOonc/BRsQrT+aFB48qF eFtTeeHBW7Rr5NWBjbAzFb9SkQyWCCRHMjf6wv0qqy0NWAzAGZISf5nQDfz/++vh j9hC7Auj8moROyrh2uXoyUGfYiRQozS2xP0idz+EGGT5G2UKRdSFLLEW4KxrAqYO rXezQTPLeHv4exlslF/eXuod6miV1Sq6NOSy/FbrgV6CHDPwM4NL6mBeQZHfM3Xa mF0CtvRhYjDR+dO/SRQkpJYs1+GbADzH23BT0wx7nUQ3mUciO2rgdizHePQllx9I AmDxgjjkiFjWObnkWHx5hKZ3i1Uiu9nislABm7oPsAK5qa4TvXsjHthuet5l4vc6 s4m9aMI0ehz0yI4hGKUUYnRoWTPcbfvni8NuFfdmBxmpIgAmaBd6LS7WSbIF9Df2 V/w0aVSI8mDHVl/9Fa+pVZQ4HJTymPD7BkNphTF692VukYVMDMaQCne3rmXotEe3 T4Bs1MYY13ezs3VuXKymzXjjiGpML+nGBzvzj9s/Itwhk2jQXIUw2sJDaTlD6fL3 /kbavQFu/jmpi6BF76CVSMbScnGO0hGZ+Gxhp/L55BO35cbLI/eBzbaNDNqe0z2O Cm4PhLlV7cOVUdaVGkkWmJ/t/NEfPtuXP85m8Suww6hfSmGBT/G/idOFIDylWBqs YORU6ksO =Car9 -----END PGP SIGNATURE----- --=_MailMate_D57647AE-4DA1-4C9B-AEDB-C24F26D9FE9B_=--