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[209.132.180.67]) by mx.google.com with ESMTP id r1si22904642plb.367.2019.03.28.11.59.45; Thu, 28 Mar 2019 12:00:01 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=alibaba.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726140AbfC1S7I (ORCPT + 99 others); Thu, 28 Mar 2019 14:59:08 -0400 Received: from out30-56.freemail.mail.aliyun.com ([115.124.30.56]:59061 "EHLO out30-56.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726045AbfC1S7I (ORCPT ); Thu, 28 Mar 2019 14:59:08 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R281e4;CH=green;DM=||false|;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01f04391;MF=yang.shi@linux.alibaba.com;NM=1;PH=DS;RN=13;SR=0;TI=SMTPD_---0TNsklAz_1553799538; Received: from US-143344MP.local(mailfrom:yang.shi@linux.alibaba.com fp:SMTPD_---0TNsklAz_1553799538) by smtp.aliyun-inc.com(127.0.0.1); Fri, 29 Mar 2019 02:59:04 +0800 Subject: Re: [RFC PATCH 0/10] Another Approach to Use PMEM as NUMA Node To: Michal Hocko Cc: Dan Williams , Mel Gorman , Rik van Riel , Johannes Weiner , Andrew Morton , Dave Hansen , Keith Busch , Fengguang Wu , "Du, Fan" , "Huang, Ying" , Linux MM , Linux Kernel Mailing List References: <1553316275-21985-1-git-send-email-yang.shi@linux.alibaba.com> <20190326135837.GP28406@dhcp22.suse.cz> <43a1a59d-dc4a-6159-2c78-e1faeb6e0e46@linux.alibaba.com> <20190326183731.GV28406@dhcp22.suse.cz> <20190327090100.GD11927@dhcp22.suse.cz> <20190327193918.GP11927@dhcp22.suse.cz> <6f8b4c51-3f3c-16f9-ca2f-dbcd08ea23e6@linux.alibaba.com> <20190328065802.GQ11927@dhcp22.suse.cz> From: Yang Shi Message-ID: <6487e0f5-aee4-3fea-00f5-c12602b8ad2b@linux.alibaba.com> Date: Thu, 28 Mar 2019 11:58:57 -0700 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <20190328065802.GQ11927@dhcp22.suse.cz> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/27/19 11:58 PM, Michal Hocko wrote: > On Wed 27-03-19 19:09:10, Yang Shi wrote: >> One question, when doing demote and promote we need define a path, for >> example, DRAM <-> PMEM (assume two tier memory). When determining what nodes >> are "DRAM" nodes, does it make sense to assume the nodes with both cpu and >> memory are DRAM nodes since PMEM nodes are typically cpuless nodes? > Do we really have to special case this for PMEM? Why cannot we simply go > in the zonelist order? In other words why cannot we use the same logic > for a larger NUMA machine and instead of swapping simply fallback to a > less contended NUMA node? It can be a regular DRAM, PMEM or whatever > other type of memory node. Thanks for the suggestion. It makes sense. However, if we don't specialize a pmem node, its fallback node may be a DRAM node, then the memory reclaim may move the inactive page to the DRAM node, it sounds not make too much sense since memory reclaim would prefer to move downwards (DRAM -> PMEM -> Disk). Yang