Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754625Ab2K0NFA (ORCPT ); Tue, 27 Nov 2012 08:05:00 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:40326 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1754030Ab2K0NE7 (ORCPT ); Tue, 27 Nov 2012 08:04:59 -0500 X-IronPort-AV: E=Sophos;i="4.83,328,1352044800"; d="scan'208";a="6285999" Message-ID: <50B4B6BE.3000902@cn.fujitsu.com> Date: Tue, 27 Nov 2012 20:49:02 +0800 From: Tang Chen User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:12.0) Gecko/20120430 Thunderbird/12.0.1 MIME-Version: 1.0 To: Bob Liu CC: 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, m.szyprowski@samsung.com Subject: Re: [PATCH v2 0/5] Add movablecore_map boot option References: <1353667445-7593-1-git-send-email-tangchen@cn.fujitsu.com> <50B479FA.6010307@cn.fujitsu.com> In-Reply-To: X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/11/27 20:49:38, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/11/27 20:49:47, Serialize complete at 2012/11/27 20:49:47 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=UTF-8; format=flowed Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1637 Lines: 43 On 11/27/2012 08:09 PM, Bob Liu wrote: > On Tue, Nov 27, 2012 at 4:29 PM, Tang Chen wrote: >> Hi Liu, >> >> This feature is used in memory hotplug. >> >> In order to implement a whole node hotplug, we need to make sure the >> node contains no kernel memory, because memory used by kernel could >> not be migrated. (Since the kernel memory is directly mapped, >> VA = PA + __PAGE_OFFSET. So the physical address could not be changed.) >> >> User could specify all the memory on a node to be movable, so that the >> node could be hot-removed. >> > > Thank you for your explanation. It's reasonable. > > But i think it's a bit duplicated with CMA, i'm not sure but maybe we > can combine it with CMA which already in mainline? > Hi Liu, Thanks for your advice. :) CMA is Contiguous Memory Allocator, right? What I'm trying to do is controlling where is the start of ZONE_MOVABLE of each node. Could CMA do this job ? And also, after a short investigation, CMA seems need to base on memblock. But we need to limit memblock not to allocate memory on ZONE_MOVABLE. As a result, we need to know the ranges before memblock could be used. I'm afraid we still need an approach to get the ranges, such as a boot option, or from static ACPI tables such as SRAT/MPST. I'm don't know much about CMA for now. So if you have any better idea, please share with us, thanks. :) -- 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/