From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx122.postini.com [74.125.245.122]) by kanga.kvack.org (Postfix) with SMTP id D31616B005D for ; Tue, 21 Aug 2012 08:12:14 -0400 (EDT) Received: by dadi14 with SMTP id i14so617322dad.14 for ; Tue, 21 Aug 2012 05:12:14 -0700 (PDT) Message-ID: <50337B15.2090701@gmail.com> Date: Tue, 21 Aug 2012 20:12:05 +0800 From: qiuxishi MIME-Version: 1.0 Subject: [PATCH] memory-hotplug: fix a drain pcp bug when offline pages Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org, minchan@kernel.org, lliubbo@gmail.com, jiang.liu@huawei.com Cc: mgorman@suse.de, kamezawa.hiroyu@jp.fujitsu.com, mhocko@suse.cz, linux-mm@kvack.org, linux-kernel@vger.kernel.org, qiuxishi@huawei.com, wujianguo@huawei.com, bessel.wang@huawei.com, guohanjun@huawei.com, chenkeping@huawei.com, yinghai@kernel.org, wency@cn.fujitsu.com From: Xishi Qiu When offline a section, we move all the free pages and pcp into MIGRATE_ISOLATE list first. start_isolate_page_range() set_migratetype_isolate() drain_all_pages(), Here is a problem, it is not sure that pcp will be moved into MIGRATE_ISOLATE list. They may be moved into MIGRATE_MOVABLE list because page_private() maybe 2. So when finish migrating pages, the free pages from pcp may be allocated again, and faild in check_pages_isolated(). drain_all_pages() drain_local_pages() drain_pages() free_pcppages_bulk() __free_one_page(page, zone, 0, page_private(page)); If we add move_freepages_block() after drain_all_pages(), it can not sure that all the pcp will be moved into MIGRATE_ISOLATE list when the system works on high load. The free pages which from pcp may immediately be allocated again. I think the similar bug described in http://marc.info/?t=134250882300003&r=1&w=2 Signed-off-by: Xishi Qiu --- mm/page_alloc.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index d0723b2..501f6de 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -673,7 +673,8 @@ static void free_pcppages_bulk(struct zone *zone, int count, /* must delete as __free_one_page list manipulates */ list_del(&page->lru); /* MIGRATE_MOVABLE list may include MIGRATE_RESERVEs */ - __free_one_page(page, zone, 0, page_private(page)); + __free_one_page(page, zone, 0, + get_pageblock_migratetype(page)); trace_mm_page_pcpu_drain(page, 0, page_private(page)); } while (--to_free && --batch_free && !list_empty(list)); } -- 1.7.6.1 . . -- 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