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=-2.5 required=3.0 tests=MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT autolearn=ham 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 D9CD9C0044C for ; Thu, 1 Nov 2018 09:22:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9CC8B20657 for ; Thu, 1 Nov 2018 09:22:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9CC8B20657 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727973AbeKASYY (ORCPT ); Thu, 1 Nov 2018 14:24:24 -0400 Received: from mx2.suse.de ([195.135.220.15]:49342 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726520AbeKASYY (ORCPT ); Thu, 1 Nov 2018 14:24:24 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id A472EAF62; Thu, 1 Nov 2018 09:22:13 +0000 (UTC) Date: Thu, 1 Nov 2018 10:22:12 +0100 From: Michal Hocko To: Baoquan He Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: Memory hotplug failed to offline on bare metal system of multiple nodes Message-ID: <20181101092212.GB23921@dhcp22.suse.cz> References: <20181101091055.GA15166@MiWiFi-R3L-srv> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181101091055.GA15166@MiWiFi-R3L-srv> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu 01-11-18 17:10:55, Baoquan He wrote: > Hi, > > A hot removal failure was met on one bare metal system with 8 nodes, and > node1~7 are all hotpluggable and 'movable_node' is set. When try to check > value of /sys/devices/system/node/node1/memory*/removable, found some of > them are 0, namely un-removable. And a back trace will always be seen. After > bisecting, it points at criminal commit: > > 15c30bc09085 ("mm, memory_hotplug: make has_unmovable_pages more robust") > > Reverting it fix the failure, and node1~7 can be hot removed and hot > added again. From the log of commit 15c30bc09085, it's to fix a > movable_core setting issue which we allocated node_data firstly in > initmem_init(), then try to mark it as movable in mm_init(). We may need > think about it further to fix it, meanwhile not breaking bare metal > system. > > I haven't figured out why the above commit caused those memmory > block in MOVABL zone being not removable. Still checking. Attach the > tested reverting patch in this mail. Could you check which of the test inside has_unmovable_pages claimed the failure? Going back to marking movable_zone as guaranteed to offline is just too fragile. -- Michal Hocko SUSE Labs