From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx118.postini.com [74.125.245.118]) by kanga.kvack.org (Postfix) with SMTP id 649396B0044 for ; Wed, 19 Sep 2012 21:12:08 -0400 (EDT) Message-ID: <505A6EB7.5070305@cn.fujitsu.com> Date: Thu, 20 Sep 2012 09:17:43 +0800 From: Wen Congyang MIME-Version: 1.0 Subject: Re: [PATCH] memory-hotplug: fix zone stat mismatch References: <1348039748-32111-1-git-send-email-minchan@kernel.org> <20120919201738.GA2425@barrios> In-Reply-To: <20120919201738.GA2425@barrios> Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim Cc: KOSAKI Motohiro , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Kamezawa Hiroyuki , Yasuaki Ishimatsu , Shaohua Li At 09/20/2012 04:17 AM, Minchan Kim Wrote: > Hi KOSAKI, > > On Wed, Sep 19, 2012 at 02:05:20PM -0400, KOSAKI Motohiro wrote: >> On Wed, Sep 19, 2012 at 3:29 AM, Minchan Kim wrote: >>> During memory-hotplug stress test, I found NR_ISOLATED_[ANON|FILE] >>> are increasing so that kernel are hang out. >>> >>> The cause is that when we do memory-hotadd after memory-remove, >>> __zone_pcp_update clear out zone's ZONE_STAT_ITEMS in setup_pageset >>> without draining vm_stat_diff of all CPU. >>> >>> This patch fixes it. >> >> zone_pcp_update() is called from online pages path. but IMHO, >> the statistics should be drained offline path. isn't it? > > It isn't necessary because statistics is right until we reset it to zero > in online path. > Do you have something on your mind that we have to drain it in offline path? When a node is offlined and onlined again. We create node_data[i] in the function hotadd_new_pgdat(), and we will lost the statistics stored in zone->pageset. So we should drain it in offline path. Thanks Wen Congyang > >> >> thanks. > -- 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