From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx121.postini.com [74.125.245.121]) by kanga.kvack.org (Postfix) with SMTP id F18B86B0044 for ; Tue, 27 Nov 2012 01:48:00 -0500 (EST) Message-ID: <50B461EA.4090506@huawei.com> Date: Tue, 27 Nov 2012 14:47:06 +0800 From: Jianguo Wu MIME-Version: 1.0 Subject: Re: [PATCH v2 0/5] Add movablecore_map boot option References: <1353667445-7593-1-git-send-email-tangchen@cn.fujitsu.com> <50B42F32.4050107@gmail.com> <50B45318.3020605@cn.fujitsu.com> In-Reply-To: <50B45318.3020605@cn.fujitsu.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Tang Chen Cc: wujianguo , hpa@zytor.com, akpm@linux-foundation.org, rob@landley.net, isimatu.yasuaki@jp.fujitsu.com, laijs@cn.fujitsu.com, wency@cn.fujitsu.com, linfeng@cn.fujitsu.com, jiang.liu@huawei.com, yinghai@kernel.org, kosaki.motohiro@jp.fujitsu.com, minchan.kim@gmail.com, mgorman@suse.de, rientjes@google.com, rusty@rustcorp.com.au, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-doc@vger.kernel.org On 2012/11/27 13:43, Tang Chen wrote: > On 11/27/2012 11:10 AM, wujianguo wrote: >> On 2012-11-23 18:44, Tang Chen wrote: >>> [What we are doing] >>> This patchset provide a boot option for user to specify ZONE_MOVABLE memory >>> map for each node in the system. >>> >>> movablecore_map=nn[KMG]@ss[KMG] >>> >> >> Hi Tang, >> DMA address can't be set as movable, if some one boot kernel with >> movablecore_map=4G@0xa00000 or other memory region that contains DMA address, >> system maybe boot failed. Should this case be handled or mentioned >> in the change log and kernel-parameters.txt? > > Hi Wu, > > Right, DMA address can't be set as movable. And I should have mentioned > it in the doc more clear. :) > > Actually, the situation is not only for DMA address. Because we limited > the memblock allocation, even if users did not specified the DMA > address, but set too much memory as movable, which means there was too > little memory for kernel to use, kernel will also fail to boot. > > I added the following info into doc, but obviously it was not clear > enough. :) > + If kernelcore or movablecore is also specified, > + movablecore_map will have higher priority to be > + satisfied. So the administrator should be careful that > + the amount of movablecore_map areas are not too large. > + Otherwise kernel won't have enough memory to start. > > > And about how to fix it, as you said, we can handle the situation if > user specified DMA address as movable. But how to handle "too little > memory for kernel to start" case ? Is there any info about how much > at least memory kernel needs ? > As I know, bootmem is mostly used by page structs when CONFIG_SPARSEMEM=y. But it is hard to calculate how much bootmem is needed exactly. > > Thanks for the comments. :) > >> >> Thanks, >> Jianguo Wu >> > > > > . > -- 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