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[23.128.96.18]) by mx.google.com with ESMTP id w11si4201167edq.29.2020.07.01.07.33.22; Wed, 01 Jul 2020 07:33:48 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731431AbgGAOcU (ORCPT + 99 others); Wed, 1 Jul 2020 10:32:20 -0400 Received: from mga01.intel.com ([192.55.52.88]:44452 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731328AbgGAOcT (ORCPT ); Wed, 1 Jul 2020 10:32:19 -0400 IronPort-SDR: BLdzghiPKst31UcPYVThfCPiBLDbJGEnmGtRzdUXTmsTbPIwmngUgYMLUxKUsolObxlBO2qYFi yJi4+e3LcgMw== X-IronPort-AV: E=McAfee;i="6000,8403,9668"; a="164601737" X-IronPort-AV: E=Sophos;i="5.75,300,1589266800"; d="scan'208";a="164601737" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Jul 2020 07:32:18 -0700 IronPort-SDR: xMZRsEBocY4ou+X3JlDrChWzZ4wk4zF+4qSsdv8rZwGe+mSaTYpIZ1H1TrEOwIlNVZUdFGoDbi 0Y5TB98auCeQ== X-IronPort-AV: E=Sophos;i="5.75,300,1589266800"; d="scan'208";a="455124215" Received: from rapyeatx-mobl3.amr.corp.intel.com (HELO [10.255.2.31]) ([10.255.2.31]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Jul 2020 07:32:17 -0700 Subject: Re: [RFC] [PATCH 0/8] Migrate Pages in lieu of discard To: Zi Yan Cc: Shakeel Butt , Dave Hansen , LKML , Linux MM , Yang Shi , David Rientjes , Huang Ying , Dan Williams References: <20200629234503.749E5340@viggo.jf.intel.com> <654d785f-3fe5-d8bd-86bf-bf7431527184@intel.com> <8927EC7B-76F2-4DFC-9AD8-EC2F15E3CEF9@nvidia.com> From: Dave Hansen Autocrypt: addr=dave.hansen@intel.com; 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Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: <8927EC7B-76F2-4DFC-9AD8-EC2F15E3CEF9@nvidia.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 On 7/1/20 7:24 AM, Zi Yan wrote: > On 30 Jun 2020, at 15:31, Dave Hansen wrote: >>> BTW is this proposal only for systems having multi-tiers of >>> memory? Can a multi-node DRAM-only system take advantage of >>> this proposal? For example I have a system with two DRAM nodes >>> running two jobs hardwalled to each node. For each job the >>> other node is kind of low-tier memory. If I can describe the >>> per-job demotion paths then these jobs can take advantage of >>> this proposal during occasional peaks. >> I don't see any reason it could not work there. There would just >> need to be a way to set up a different demotion path policy that >> what was done here. > We might need a different threshold (or GFP flag) for allocating > new pages in remote node for demotion. Otherwise, we could see > scenarios like: two nodes in a system are almost full and Node A > is trying to demote some pages to Node B, which triggers page > demotion from Node B to Node A. I've always assumed that migration cycles would be illegal since it's so hard to guarantee forward reclaim progress with them in place. -----BEGIN PGP SIGNATURE----- iQIcBAEBCAAGBQJe/J5kAAoJEGg1lTBwyZKw0TMP/1kufbxVGSY331xhOL/QHEoE Tsuo62l2CJ/CbhIBKzac24k1Rf9AiyxUukkVZfa32c2Kf03XWjUNiWVuRPSTMlfT E0h2llYYbUBs+eVeT4Ksz4xkThKHlXPNuS1OMhuSVbjhieiPqp3J0blohXaWdkSa DBgpiqNlVPD7V0NIA5qfsumZRrOJDdJNdLKbjI7GBVprEHu5N/X0NQpakPErtcka kSz7Hjv5x+fbd3rxc2QhrnegBE1oMQGUl14nf/kIKnKuZV2WIdabaxrYWrQBvALa Z2sfcBRU41/SKvz/syCwJpSr1XkfsjNKvDMlkflXndMTzzP4/rhAyDX5Wzw99Aws zz6UmRhZrFOudq4R5jpOqJiDfn1RGYA8mH04bEOPjEgGRiXaxi5Sp6fh/BQG5p7n QESH0LVHEhg8h+10FWZ5VYU1UwMIdzolBI8Y8VlJDjeSpzSFyyDFP7Re3OyQRfmb ij5ThSozo35t+zEYS4yofgPMZKJ/aZ+EySEF5LZsipKC2RsRuFFpaDSOOGXZKLXq G/R9g2LeLZK6iNNlCrIGjeAAKN8UZzOMJwapYV8czt0HTQ2vRjuDE1Y2TRD6gjXI x6vUCfFyOEJw4l3mca+Sb1pmFcaiXBRxBrat6q23Ls+eCDMIaTgx5wA7NEeq0Td7 yShQbtIvJKRubiscJlZ/ =MjgB -----END PGP SIGNATURE-----