From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx187.postini.com [74.125.245.187]) by kanga.kvack.org (Postfix) with SMTP id 087006B0070 for ; Mon, 17 Sep 2012 10:21:37 -0400 (EDT) Date: Mon, 17 Sep 2012 15:21:30 +0100 From: Mel Gorman Subject: Re: [PATCH RESEND] memory hotplug: fix a double register section info bug Message-ID: <20120917142130.GH11266@suse.de> References: <5052A7DF.4050301@gmail.com> <20120914095230.GE11266@suse.de> <3908561D78D1C84285E8C5FCA982C28F19D40E81@ORSMSX108.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <3908561D78D1C84285E8C5FCA982C28F19D40E81@ORSMSX108.amr.corp.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: "Luck, Tony" Cc: qiuxishi , "akpm@linux-foundation.org" , Jiang Liu , "qiuxishi@huawei.com" , "bessel.wang@huawei.com" , "wujianguo@huawei.com" , "paul.gortmaker@windriver.com" , "kamezawa.hiroyu@jp.fujitsu.com" , "kosaki.motohiro@jp.fujitsu.com" , "rientjes@google.com" , Minchan Kim , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Wen Congyang On Fri, Sep 14, 2012 at 04:24:32PM +0000, Luck, Tony wrote: > > This is an unusual configuration but it's not unheard of. PPC64 in rare > > (and usually broken) configurations can have one node span another. Tony > > should know if such a configuration is normally allowed on Itanium or if > > this should be considered a platform bug. Tony? > > We definitely have platforms where the physical memory on node 0 > that we skipped to leave physical address space for PCI mem mapped > devices gets tagged back at the very top of memory, after other nodes. > > E.g. A 2-node system with 8G on each might look like this: > > 0-2G RAM on node 0 > 2G-4G PCI map space > 4G-8G RAM on node 0 > 8G-16GRAM on node 1 > 16G-18G RAM on node 0 > > Is this the situation that we are talking about? Or something different? > This is the type of situation we are talking about. The spanned range of node 0 includes node 1. The patch needs another revision with a comment explaining the situation included but otherwise the patch should be fine. -- Mel Gorman SUSE Labs -- 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