From patchwork Tue Nov 27 10:00:11 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wen Congyang X-Patchwork-Id: 1809831 Return-Path: X-Original-To: patchwork-linux-sh@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork2.kernel.org (Postfix) with ESMTP id 4507BDF254 for ; Tue, 27 Nov 2012 09:58:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758621Ab2K0J6R (ORCPT ); Tue, 27 Nov 2012 04:58:17 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:39629 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1758581Ab2K0J6O (ORCPT ); Tue, 27 Nov 2012 04:58:14 -0500 X-IronPort-AV: E=Sophos;i="4.83,327,1352044800"; d="scan'208";a="6284831" Received: from unknown (HELO tang.cn.fujitsu.com) ([10.167.250.3]) by song.cn.fujitsu.com with ESMTP; 27 Nov 2012 17:56:28 +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 qAR9voAv002831; Tue, 27 Nov 2012 17:58:08 +0800 Received: from ghost.fnst.cn.fujitsu.com ([10.167.225.226]) by fnstmail02.fnst.cn.fujitsu.com (Lotus Domino Release 8.5.3) with ESMTP id 2012112717532907-97629 ; Tue, 27 Nov 2012 17:53:29 +0800 From: Wen Congyang To: 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 Cc: David Rientjes , Jiang Liu , Len Brown , benh@kernel.crashing.org, paulus@samba.org, Christoph Lameter , Minchan Kim , Andrew Morton , KOSAKI Motohiro , Yasuaki Ishimatsu , Jianguo Wu , Wen Congyang Subject: [Patch v4 01/12] memory-hotplug: try to offline the memory twice to avoid dependence Date: Tue, 27 Nov 2012 18:00:11 +0800 Message-Id: <1354010422-19648-2-git-send-email-wency@cn.fujitsu.com> X-Mailer: git-send-email 1.8.0 In-Reply-To: <1354010422-19648-1-git-send-email-wency@cn.fujitsu.com> References: <1354010422-19648-1-git-send-email-wency@cn.fujitsu.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/11/27 17:53:29, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/11/27 17:57:46, Serialize complete at 2012/11/27 17:57:46 Sender: linux-sh-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org 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. CC: David Rientjes CC: Jiang Liu CC: Len Brown CC: Christoph Lameter Cc: Minchan Kim CC: Andrew Morton CC: KOSAKI Motohiro CC: Yasuaki Ishimatsu Signed-off-by: Wen Congyang Reviewed-by: Tang Chen --- mm/memory_hotplug.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index e4eeaca..b825dbc 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1012,10 +1012,13 @@ 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)) @@ -1034,14 +1037,23 @@ 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