From patchwork Thu Nov 1 09:44:33 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wen Congyang X-Patchwork-Id: 1683971 Return-Path: X-Original-To: patchwork-linux-sh@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork1.kernel.org (Postfix) with ESMTP id 4FB663FCDF for ; Thu, 1 Nov 2012 09:41:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933251Ab2KAJlO (ORCPT ); Thu, 1 Nov 2012 05:41:14 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:38886 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1759110Ab2KAJjJ (ORCPT ); Thu, 1 Nov 2012 05:39:09 -0400 X-IronPort-AV: E=Sophos;i="4.80,693,1344182400"; d="scan'208";a="6116042" Received: from unknown (HELO tang.cn.fujitsu.com) ([10.167.250.3]) by song.cn.fujitsu.com with ESMTP; 01 Nov 2012 17:37:23 +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 qA19ctrF007250; Thu, 1 Nov 2012 17:38:55 +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 2012110117381050-909186 ; Thu, 1 Nov 2012 17:38:10 +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 v3 02/12] memory-hotplug: check whether all memory blocks are offlined or not when removing memory Date: Thu, 1 Nov 2012 17:44:33 +0800 Message-Id: <1351763083-7905-3-git-send-email-wency@cn.fujitsu.com> X-Mailer: git-send-email 1.8.0 In-Reply-To: <1351763083-7905-1-git-send-email-wency@cn.fujitsu.com> References: <1351763083-7905-1-git-send-email-wency@cn.fujitsu.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/11/01 17:38:10, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/11/01 17:38:13, Serialize complete at 2012/11/01 17:38:13 Sender: linux-sh-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org From: Yasuaki Ishimatsu We remove the memory like this: 1. lock memory hotplug 2. offline a memory block 3. unlock memory hotplug 4. repeat 1-3 to offline all memory blocks 5. lock memory hotplug 6. remove memory(TODO) 7. unlock memory hotplug All memory blocks must be offlined before removing memory. But we don't hold the lock in the whole operation. So we should check whether all memory blocks are offlined before step6. Otherwise, kernel maybe panicked. CC: David Rientjes CC: Jiang Liu CC: Len Brown CC: Christoph Lameter Cc: Minchan Kim CC: Andrew Morton CC: KOSAKI Motohiro Signed-off-by: Wen Congyang Signed-off-by: Yasuaki Ishimatsu --- drivers/base/memory.c | 6 ++++++ include/linux/memory_hotplug.h | 1 + mm/memory_hotplug.c | 47 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 54 insertions(+) diff --git a/drivers/base/memory.c b/drivers/base/memory.c index 86c8821..badb025 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -675,6 +675,12 @@ int offline_memory_block(struct memory_block *mem) return ret; } +/* return true if the memory block is offlined, otherwise, return false */ +bool is_memblock_offlined(struct memory_block *mem) +{ + return mem->state == MEM_OFFLINE; +} + /* * Initialize the sysfs support for memory devices... */ diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h index 95573ec..38675e9 100644 --- a/include/linux/memory_hotplug.h +++ b/include/linux/memory_hotplug.h @@ -236,6 +236,7 @@ extern int add_memory(int nid, u64 start, u64 size); extern int arch_add_memory(int nid, u64 start, u64 size); extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages); extern int offline_memory_block(struct memory_block *mem); +extern bool is_memblock_offlined(struct memory_block *mem); extern int remove_memory(u64 start, u64 size); extern int sparse_add_one_section(struct zone *zone, unsigned long start_pfn, int nr_pages); diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 600e200..f4fdedd 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1061,6 +1061,53 @@ repeat: goto repeat; } + lock_memory_hotplug(); + + /* + * we have offlined all memory blocks like this: + * 1. lock memory hotplug + * 2. offline a memory block + * 3. unlock memory hotplug + * + * repeat step1-3 to offline the memory block. All memory blocks + * must be offlined before removing memory. But we don't hold the + * lock in the whole operation. So we should check whether all + * memory blocks are offlined. + */ + + for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { + section_nr = pfn_to_section_nr(pfn); + if (!present_section_nr(section_nr)) + continue; + + section = __nr_to_section(section_nr); + /* same memblock? */ + if (mem) + if ((section_nr >= mem->start_section_nr) && + (section_nr <= mem->end_section_nr)) + continue; + + mem = find_memory_block_hinted(section, mem); + if (!mem) + continue; + + ret = is_memblock_offlined(mem); + if (!ret) { + pr_warn("removing memory fails, because memory " + "[%#010llx-%#010llx] is onlined\n", + PFN_PHYS(section_nr_to_pfn(mem->start_section_nr)), + PFN_PHYS(section_nr_to_pfn(mem->end_section_nr + 1)) - 1); + + kobject_put(&mem->dev.kobj); + unlock_memory_hotplug(); + return ret; + } + } + + if (mem) + kobject_put(&mem->dev.kobj); + unlock_memory_hotplug(); + return 0; } #else