Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753371AbbDTC1v (ORCPT ); Sun, 19 Apr 2015 22:27:51 -0400 Received: from cn.fujitsu.com ([59.151.112.132]:47178 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1751887AbbDTC1u (ORCPT ); Sun, 19 Apr 2015 22:27:50 -0400 X-IronPort-AV: E=Sophos;i="5.04,848,1406563200"; d="scan'208";a="90914116" Message-ID: <55345FAB.7000607@cn.fujitsu.com> Date: Mon, 20 Apr 2015 10:08:43 +0800 From: Gu Zheng User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:7.0.1) Gecko/20110930 Thunderbird/7.0.1 MIME-Version: 1.0 To: Yasuaki Ishimatsu , Xishi Qiu CC: Andrew Morton , Yasuaki Ishimatsu , Kamezawa Hiroyuki , , Tang Chen , Xiexiuqi , Mel Gorman , David Rientjes , Linux MM , LKML Subject: Re: [PATCH 1/2 V2] memory-hotplug: fix BUG_ON in move_freepages() References: <5530E578.9070505@huawei.com> <5531679d.4642ec0a.1beb.3569@mx.google.com> <55345756.40902@huawei.com> <5534603a.36208c0a.4784.6286@mx.google.com> In-Reply-To: <5534603a.36208c0a.4784.6286@mx.google.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.167.226.100] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2265 Lines: 86 Hi Ishimatsu, Xishi, On 04/20/2015 10:11 AM, Yasuaki Ishimatsu wrote: > >> When hot adding memory and creating new node, the node is offline. >> And after calling node_set_online(), the node becomes online. >> >> Oh, sorry. I misread your ptaches. >> > > Please ignore it... Seems also a misread to me. I clear it (my worry) here: If we set the node size to 0 here, it may hidden more things than we experted, and all the init chunks around with the size (spanned/present/managed...) will be non-sense, and the user/caller will not get a summary of the hot added node because of the changes here. I am not sure the worry is necessary, please correct me if I missing something. Regards, Gu > > Thanks, > Yasuaki Ishimatsu > > On > Yasuaki Ishimatsu wrote: > >> >> When hot adding memory and creating new node, the node is offline. >> And after calling node_set_online(), the node becomes online. >> >> Oh, sorry. I misread your ptaches. >> >> Thanks, >> Yasuaki Ishimatsu >> >> On Mon, 20 Apr 2015 09:33:10 +0800 >> Xishi Qiu wrote: >> >>> On 2015/4/18 4:05, Yasuaki Ishimatsu wrote: >>> >>>> >>>> Your patches will fix your issue. >>>> But, if BIOS reports memory first at node hot add, pgdat can >>>> not be initialized. >>>> >>>> Memory hot add flows are as follows: >>>> >>>> add_memory >>>> ... >>>> -> hotadd_new_pgdat() >>>> ... >>>> -> node_set_online(nid) >>>> >>>> When calling hotadd_new_pgdat() for a hot added node, the node is >>>> offline because node_set_online() is not called yet. So if applying >>>> your patches, the pgdat is not initialized in this case. >>>> >>>> Thanks, >>>> Yasuaki Ishimatsu >>>> >>> >>> Hi Yasuaki, >>> >>> I'm not quite understand, when BIOS reports memory first, why pgdat >>> can not be initialized? >>> When hotadd a new node, hotadd_new_pgdat() will be called too, and >>> when hotadd memory to a existent node, it's no need to call hotadd_new_pgdat(), >>> right? >>> >>> Thanks, >>> Xishi Qiu >>> > . > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/