From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from d03relay02.boulder.ibm.com (d03relay02.boulder.ibm.com [9.17.195.227]) by e32.co.us.ibm.com (8.12.11.20060308/8.13.8) with ESMTP id l9VEH3Hc000688 for ; Wed, 31 Oct 2007 10:17:03 -0400 Received: from d03av01.boulder.ibm.com (d03av01.boulder.ibm.com [9.17.195.167]) by d03relay02.boulder.ibm.com (8.13.8/8.13.8/NCO v8.5) with ESMTP id l9VFGDT0112324 for ; Wed, 31 Oct 2007 09:17:21 -0600 Received: from d03av01.boulder.ibm.com (loopback [127.0.0.1]) by d03av01.boulder.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id l9VExBTA028910 for ; Wed, 31 Oct 2007 08:59:11 -0600 Subject: Re: [RFC] hotplug memory remove - walk_memory_resource for ppc64 From: Badari Pulavarty In-Reply-To: <20071031143423.586498c3.kamezawa.hiroyu@jp.fujitsu.com> References: <1191346196.6106.20.camel@dyn9047017100.beaverton.ibm.com> <18178.52359.953289.638736@cargo.ozlabs.ibm.com> <1193771951.8904.22.camel@dyn9047017100.beaverton.ibm.com> <20071031142846.aef9c545.kamezawa.hiroyu@jp.fujitsu.com> <20071031143423.586498c3.kamezawa.hiroyu@jp.fujitsu.com> Content-Type: text/plain Date: Wed, 31 Oct 2007 08:02:40 -0800 Message-Id: <1193846560.17412.3.camel@dyn9047017100.beaverton.ibm.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: KAMEZAWA Hiroyuki Cc: Paul Mackerras , linuxppc-dev@ozlabs.org, linux-mm , anton@au1.ibm.com List-ID: On Wed, 2007-10-31 at 14:34 +0900, KAMEZAWA Hiroyuki wrote: > On Wed, 31 Oct 2007 14:28:46 +0900 > KAMEZAWA Hiroyuki wrote: > > > ioresource was good structure for remembering "which memory is conventional > > memory" and i386/x86_64/ia64 registered conventional memory as "System RAM", > > when I posted patch. (just say "System Ram" is not for memory hotplug.) > > > If I remember correctly, System RAM is for kdump (to know which memory should > be dumped.) Then, memory-hotadd/remove has to modify it anyway. Yes. kdump uses it for finding memory holes on x86/x86-64 (not sure about ia64). On PPC64, since its not represented in /proc/iomem, we end up reading /proc/device-tree/memory* nodes to construct the memory map. Paul's concern is, since we didn't need it so far - why we need this for hotplug memory remove to work ? It might break API for *unknown* applications. Its unfortunate that, hotplug memory add updates /proc/iomem. We can deal with it later, as a separate patch. Thanks, Badari -- 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