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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,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 2AA53C433F5 for ; Tue, 21 Sep 2021 17:03:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 04EC560E52 for ; Tue, 21 Sep 2021 17:03:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231663AbhIURDt (ORCPT ); Tue, 21 Sep 2021 13:03:49 -0400 Received: from mga12.intel.com ([192.55.52.136]:58174 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229912AbhIURDj (ORCPT ); Tue, 21 Sep 2021 13:03:39 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10114"; a="202911756" X-IronPort-AV: E=Sophos;i="5.85,311,1624345200"; d="scan'208";a="202911756" Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Sep 2021 10:01:36 -0700 X-IronPort-AV: E=Sophos;i="5.85,311,1624345200"; d="scan'208";a="435946559" Received: from adkuncha-mobl2.amr.corp.intel.com (HELO [10.251.2.103]) ([10.251.2.103]) by orsmga003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Sep 2021 10:01:36 -0700 Subject: Re: [PATCH 1/2] mm/migrate: optimize hotplug-time demotion order updates To: "Huang, Ying" Cc: Dave Hansen , linux-kernel@vger.kernel.org, oliver.sang@intel.com, mhocko@suse.com, weixugc@google.com, osalvador@suse.de, rientjes@google.com, dan.j.williams@intel.com, david@redhat.com, gthelen@google.com, yang.shi@linux.alibaba.com, akpm@linux-foundation.org References: <20210917223504.C140445A@davehans-spike.ostc.intel.com> <20210917223505.F817CB6B@davehans-spike.ostc.intel.com> <87k0jeog7r.fsf@yhuang6-desk2.ccr.corp.intel.com> <2d7e4078-f9c0-7511-0bab-de5dab25b45d@intel.com> <87a6k66lnd.fsf@yhuang6-desk2.ccr.corp.intel.com> From: Dave Hansen Autocrypt: addr=dave.hansen@intel.com; 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Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <87a6k66lnd.fsf@yhuang6-desk2.ccr.corp.intel.com> Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/21/21 7:36 AM, Huang, Ying wrote: >> This removes the need for the demotion code to track *any* state. I've >> attached a totally untested patch to do this. > Yes. This sounds good. I will try to test this patch on my side. > >>>From another point of view, we still need to update demotion order upon > CPU hotplug too, because whether a node has CPU may be changed there. > And we need a solution for that too. Just to recap... The reason I sent this series is that there's a known, detectable regression in a memory hotplug "benchmark". This affects the 5.15 series. While I agree that we should look into the impact on CPU hotplug, I think we should probably focus on the *known* memory hotplug issue for 5.15.