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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,UNPARSEABLE_RELAY 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 A0619C10F13 for ; Tue, 16 Apr 2019 23:17:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 639E220868 for ; Tue, 16 Apr 2019 23:17:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730829AbfDPXRv (ORCPT ); Tue, 16 Apr 2019 19:17:51 -0400 Received: from out30-42.freemail.mail.aliyun.com ([115.124.30.42]:44352 "EHLO out30-42.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728237AbfDPXRv (ORCPT ); Tue, 16 Apr 2019 19:17:51 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R111e4;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=14;SR=0;TI=SMTPD_---0TPVBBj6_1555456664; Received: from US-143344MP.local(mailfrom:yang.shi@linux.alibaba.com fp:SMTPD_---0TPVBBj6_1555456664) by smtp.aliyun-inc.com(127.0.0.1); Wed, 17 Apr 2019 07:17:48 +0800 Subject: Re: [v2 RFC PATCH 0/9] Another Approach to Use PMEM as NUMA Node To: Dave Hansen , Michal Hocko Cc: mgorman@techsingularity.net, riel@surriel.com, hannes@cmpxchg.org, akpm@linux-foundation.org, keith.busch@intel.com, dan.j.williams@intel.com, fengguang.wu@intel.com, fan.du@intel.com, ying.huang@intel.com, ziy@nvidia.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <1554955019-29472-1-git-send-email-yang.shi@linux.alibaba.com> <20190412084702.GD13373@dhcp22.suse.cz> <20190416074714.GD11561@dhcp22.suse.cz> <876768ad-a63a-99c3-59de-458403f008c4@linux.alibaba.com> <99320338-d9d3-74ca-5b07-6c3ca718800f@linux.alibaba.com> <1556283f-de69-ce65-abf8-22f6f8d7d358@intel.com> From: Yang Shi Message-ID: <8bc32012-b747-3827-1814-91942357d170@linux.alibaba.com> Date: Tue, 16 Apr 2019 16:17:44 -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: <1556283f-de69-ce65-abf8-22f6f8d7d358@intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/16/19 4:04 PM, Dave Hansen wrote: > On 4/16/19 2:59 PM, Yang Shi wrote: >> On 4/16/19 2:22 PM, Dave Hansen wrote: >>> Keith Busch had a set of patches to let you specify the demotion order >>> via sysfs for fun.  The rules we came up with were: >>> 1. Pages keep no history of where they have been >>> 2. Each node can only demote to one other node >> Does this mean any remote node? Or just DRAM to PMEM, but remote PMEM >> might be ok? > In Keith's code, I don't think we differentiated. We let any node > demote to any other node you want, as long as it follows the cycle rule. I recall Keith's code let the userspace define the target node. Anyway, we may need add one rule: not migrate-on-reclaim from PMEM node. Demoting from PMEM to DRAM sounds pointless.