From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f174.google.com (mail-pd0-f174.google.com [209.85.192.174]) by kanga.kvack.org (Postfix) with ESMTP id 6D8B76B0032 for ; Sun, 19 Apr 2015 22:27:51 -0400 (EDT) Received: by pdbqa5 with SMTP id qa5so192622031pdb.1 for ; Sun, 19 Apr 2015 19:27:51 -0700 (PDT) Received: from heian.cn.fujitsu.com ([59.151.112.132]) by mx.google.com with ESMTP id p5si26196792par.19.2015.04.19.19.27.49 for ; Sun, 19 Apr 2015 19:27:50 -0700 (PDT) Message-ID: <55345FAB.7000607@cn.fujitsu.com> Date: Mon, 20 Apr 2015 10:08:43 +0800 From: Gu Zheng MIME-Version: 1.0 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 Sender: owner-linux-mm@kvack.org List-ID: To: Yasuaki Ishimatsu , Xishi Qiu Cc: Andrew Morton , Yasuaki Ishimatsu , Kamezawa Hiroyuki , izumi.taku@jp.fujitsu.com, Tang Chen , Xiexiuqi , Mel Gorman , David Rientjes , Linux MM , LKML 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org