From patchwork Mon Dec 24 12:09:11 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tang Chen X-Patchwork-Id: 208060 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 91E1C2C05E4 for ; Mon, 24 Dec 2012 23:12:25 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753019Ab2LXMKf (ORCPT ); Mon, 24 Dec 2012 07:10:35 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:18900 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752211Ab2LXMK2 (ORCPT ); Mon, 24 Dec 2012 07:10:28 -0500 X-IronPort-AV: E=Sophos;i="4.84,347,1355068800"; d="scan'208";a="6464030" Received: from unknown (HELO tang.cn.fujitsu.com) ([10.167.250.3]) by song.cn.fujitsu.com with ESMTP; 24 Dec 2012 20:08:27 +0800 Received: from fnstmail02.fnst.cn.fujitsu.com (tang.cn.fujitsu.com [127.0.0.1]) by tang.cn.fujitsu.com (8.14.3/8.13.1) with ESMTP id qBOCARa7016665; Mon, 24 Dec 2012 20:10:27 +0800 Received: from tangchen.fnst.cn.fujitsu.com ([10.167.225.117]) by fnstmail02.fnst.cn.fujitsu.com (Lotus Domino Release 8.5.3) with ESMTP id 2012122420101288-582946 ; Mon, 24 Dec 2012 20:10:12 +0800 From: Tang Chen To: akpm@linux-foundation.org, rientjes@google.com, liuj97@gmail.com, len.brown@intel.com, benh@kernel.crashing.org, paulus@samba.org, cl@linux.com, minchan.kim@gmail.com, kosaki.motohiro@jp.fujitsu.com, isimatu.yasuaki@jp.fujitsu.com, wujianguo@huawei.com, wency@cn.fujitsu.com, tangchen@cn.fujitsu.com, hpa@zytor.com, linfeng@cn.fujitsu.com, laijs@cn.fujitsu.com, mgorman@suse.de, yinghai@kernel.org 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 Subject: [PATCH v5 01/14] memory-hotplug: try to offline the memory twice to avoid dependence Date: Mon, 24 Dec 2012 20:09:11 +0800 Message-Id: <1356350964-13437-2-git-send-email-tangchen@cn.fujitsu.com> X-Mailer: git-send-email 1.7.10.1 In-Reply-To: <1356350964-13437-1-git-send-email-tangchen@cn.fujitsu.com> References: <1356350964-13437-1-git-send-email-tangchen@cn.fujitsu.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/12/24 20:10:12, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/12/24 20:10:14, Serialize complete at 2012/12/24 20:10:14 Sender: sparclinux-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: sparclinux@vger.kernel.org From: Wen Congyang 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, iterate twice to offline the memory. 1st iterate: offline every non primary memory block. 2nd iterate: offline primary (i.e. first added) memory block. This idea is suggested by KOSAKI Motohiro. Signed-off-by: Wen Congyang --- mm/memory_hotplug.c | 16 ++++++++++++++-- 1 files changed, 14 insertions(+), 2 deletions(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index d04ed87..62e04c9 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1388,10 +1388,13 @@ int remove_memory(u64 start, u64 size) unsigned long start_pfn, end_pfn; unsigned long pfn, section_nr; int ret; + int return_on_error = 0; + int retry = 0; start_pfn = PFN_DOWN(start); end_pfn = start_pfn + PFN_DOWN(size); +repeat: for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { section_nr = pfn_to_section_nr(pfn); if (!present_section_nr(section_nr)) @@ -1410,14 +1413,23 @@ int remove_memory(u64 start, u64 size) ret = offline_memory_block(mem); if (ret) { - kobject_put(&mem->dev.kobj); - return ret; + if (return_on_error) { + kobject_put(&mem->dev.kobj); + return ret; + } else { + retry = 1; + } } } if (mem) kobject_put(&mem->dev.kobj); + if (retry) { + return_on_error = 1; + goto repeat; + } + return 0; } #else