From patchwork Tue Oct 23 10:30:39 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wen Congyang X-Patchwork-Id: 193430 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from ozlabs.org (localhost [IPv6:::1]) by ozlabs.org (Postfix) with ESMTP id AC20A2C0492 for ; Tue, 23 Oct 2012 21:26:29 +1100 (EST) Received: from song.cn.fujitsu.com (unknown [222.73.24.84]) by ozlabs.org (Postfix) with ESMTP id DD7E32C0100 for ; Tue, 23 Oct 2012 21:25:19 +1100 (EST) X-IronPort-AV: E=Sophos;i="4.80,635,1344182400"; d="scan'208";a="6052008" Received: from unknown (HELO tang.cn.fujitsu.com) ([10.167.250.3]) by song.cn.fujitsu.com with ESMTP; 23 Oct 2012 18:23:43 +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 q9NAPCe9023855; Tue, 23 Oct 2012 18:25:12 +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 2012102318244272-689737 ; Tue, 23 Oct 2012 18:24:42 +0800 From: wency@cn.fujitsu.com 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 Subject: [PATCH v2 01/12] memory-hotplug: try to offline the memory twice to avoid dependence Date: Tue, 23 Oct 2012 18:30:39 +0800 Message-Id: <1350988250-31294-2-git-send-email-wency@cn.fujitsu.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1350988250-31294-1-git-send-email-wency@cn.fujitsu.com> References: <1350988250-31294-1-git-send-email-wency@cn.fujitsu.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/10/23 18:24:42, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/10/23 18:24:44, Serialize complete at 2012/10/23 18:24:44 Cc: len.brown@intel.com, Wen Congyang , isimatu.yasuaki@jp.fujitsu.com, paulus@samba.org, minchan.kim@gmail.com, kosaki.motohiro@jp.fujitsu.com, rientjes@google.com, cl@linux.com, akpm@linux-foundation.org, liuj97@gmail.com X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" 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. 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 --- 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 56b758a..600e200 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1019,10 +1019,13 @@ 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)) @@ -1041,14 +1044,23 @@ 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