From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx161.postini.com [74.125.245.161]) by kanga.kvack.org (Postfix) with SMTP id 1AF456B005A for ; Thu, 6 Sep 2012 20:49:35 -0400 (EDT) Received: from m4.gw.fujitsu.co.jp (unknown [10.0.50.74]) by fgwmail5.fujitsu.co.jp (Postfix) with ESMTP id 40F063EE0BD for ; Fri, 7 Sep 2012 09:49:33 +0900 (JST) Received: from smail (m4 [127.0.0.1]) by outgoing.m4.gw.fujitsu.co.jp (Postfix) with ESMTP id 267FA45DE53 for ; Fri, 7 Sep 2012 09:49:33 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (s4.gw.fujitsu.co.jp [10.0.50.94]) by m4.gw.fujitsu.co.jp (Postfix) with ESMTP id 0C27445DE4E for ; Fri, 7 Sep 2012 09:49:33 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id EEA0EE08001 for ; Fri, 7 Sep 2012 09:49:32 +0900 (JST) Received: from ml14.s.css.fujitsu.com (ml14.s.css.fujitsu.com [10.240.81.134]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 90FB81DB803E for ; Fri, 7 Sep 2012 09:49:32 +0900 (JST) Message-ID: <50494473.8030008@jp.fujitsu.com> Date: Fri, 07 Sep 2012 09:48:51 +0900 From: Kamezawa Hiroyuki MIME-Version: 1.0 Subject: Re: [PATCH v3 4/4] memory-hotplug: fix pages missed by race rather than failng References: <1346978372-17903-1-git-send-email-minchan@kernel.org> <1346978372-17903-5-git-send-email-minchan@kernel.org> In-Reply-To: <1346978372-17903-5-git-send-email-minchan@kernel.org> Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Mel Gorman , Yasuaki Ishimatsu , Xishi Qiu , Wen Congyang (2012/09/07 9:39), Minchan Kim wrote: > If race between allocation and isolation in memory-hotplug offline > happens, some pages could be in MIGRATE_MOVABLE of free_list although > the pageblock's migratetype of the page is MIGRATE_ISOLATE. > > The race could be detected by get_freepage_migratetype > in __test_page_isolated_in_pageblock. If it is detected, now EBUSY > gets bubbled all the way up and the hotplug operations fails. > > But better idea is instead of returning and failing memory-hotremove, > move the free page to the correct list at the time it is detected. > It could enhance memory-hotremove operation success ratio although > the race is really rare. > > Suggested-by: Mel Gorman > Signed-off-by: Minchan Kim Sounds reasonable. Thank you very much ! Acked-by: KAMEZAWA Hiroyuki -- 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