From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx190.postini.com [74.125.245.190]) by kanga.kvack.org (Postfix) with SMTP id DCD826B0062 for ; Fri, 5 Oct 2012 15:07:00 -0400 (EDT) Received: by mail-oa0-f41.google.com with SMTP id k14so2517889oag.14 for ; Fri, 05 Oct 2012 12:07:00 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <506E43E0.70507@jp.fujitsu.com> References: <506E43E0.70507@jp.fujitsu.com> From: KOSAKI Motohiro Date: Fri, 5 Oct 2012 15:06:35 -0400 Message-ID: Subject: Re: [PATCH 0/10] memory-hotplug: hot-remove physical memory Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: Yasuaki Ishimatsu Cc: x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-acpi@vger.kernel.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, linux-ia64@vger.kernel.org, cmetcalf@tilera.com, sparclinux@vger.kernel.org, rientjes@google.com, liuj97@gmail.com, len.brown@intel.com, cl@linux.com, minchan.kim@gmail.com, akpm@linux-foundation.org, wency@cn.fujitsu.com > Known problems: > 1. memory can't be offlined when CONFIG_MEMCG is selected. > For example: there is a memory device on node 1. The address range > is [1G, 1.5G). You will find 4 new directories memory8, memory9, memory10, > and memory11 under the directory /sys/devices/system/memory/. > If CONFIG_MEMCG is selected, we will allocate memory to store page cgroup > when we online pages. When we online memory8, the memory stored page cgroup > is not provided by this memory device. But when we online memory9, the memory > stored page cgroup may be provided by memory8. So we can't offline memory8 > now. We should offline the memory in the reversed order. > When the memory device is hotremoved, we will auto offline memory provided > by this memory device. But we don't know which memory is onlined first, so > offlining memory may fail. In such case, you should offline the memory by > hand before hotremoving the memory device. Just iterate twice. 1st iterate: offline every non primary memory block. 2nd iterate: offline primary (i.e. first added) memory block. It may work. -- 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