From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ie0-f172.google.com (mail-ie0-f172.google.com [209.85.223.172]) by kanga.kvack.org (Postfix) with ESMTP id 1117B6B0032 for ; Sun, 19 Apr 2015 23:36:06 -0400 (EDT) Received: by iecrt8 with SMTP id rt8so94880561iec.0 for ; Sun, 19 Apr 2015 20:36:05 -0700 (PDT) Received: from szxga01-in.huawei.com (szxga01-in.huawei.com. [58.251.152.64]) by mx.google.com with ESMTPS id e4si6966625igc.10.2015.04.19.20.36.02 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Sun, 19 Apr 2015 20:36:05 -0700 (PDT) Message-ID: <553473CD.9020600@huawei.com> Date: Mon, 20 Apr 2015 11:34:37 +0800 From: Xishi Qiu 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> <55345FC4.4070404@cn.fujitsu.com> <55346B99.2060602@huawei.com> <55346f49.8bc6ec0a.5fe5.ffffcdac@mx.google.com> In-Reply-To: <55346f49.8bc6ec0a.5fe5.ffffcdac@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 Cc: Gu Zheng , Andrew Morton , Yasuaki Ishimatsu , Kamezawa Hiroyuki , izumi.taku@jp.fujitsu.com, Tang Chen , Xiexiuqi , Mel Gorman , David Rientjes , Linux MM , LKML On 2015/4/20 11:15, Yasuaki Ishimatsu wrote: > > On Mon, 20 Apr 2015 10:59:37 +0800 > Xishi Qiu wrote: > >> On 2015/4/20 10:09, Gu Zheng wrote: >> >>> 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. >>> 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 >>> >> >> Hi Gu, >> >> My patch is just set size to 0 when hotadd a node(old or new). I know your worry, >> but I think it is not necessary. >> > >> When we calculate the size, it uses "arch_zone_lowest_possible_pfn[]" and "memblock", >> and they are both from boot time. If we hotadd a new node, the calculated size is >> 0 too. When add momery, __add_zone() will grow the size and start. > > If hot adding new node, you are right. But if hot removing a memory which > is presented at boot time, memblock of the memory range is not deleted. > So when hot adding the memory, the calculated size does not become 0. > Yes, so I just set it to 0, init_currently_empty_zone() and memmap_init() will be called in __add_zone(), and start/size also will be grow there. Thanks, Xishi Qiu > Thanks, > Yasuaki Ishimatsu > >> >> 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