From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with SMTP id CC8FD6B0071 for ; Sun, 17 Jan 2010 21:16:14 -0500 (EST) Message-ID: <4B53C466.4010103@redhat.com> Date: Sun, 17 Jan 2010 21:16:06 -0500 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [PATCH 2/3][v2] vmstat: add anon_scan_ratio field to zoneinfo References: <20100118100359.AE22.A69D9226@jp.fujitsu.com> <28c262361001171747w450c8fd8j4daf84b72fb68e1a@mail.gmail.com> <20100118104910.AE2D.A69D9226@jp.fujitsu.com> <28c262361001171810w544614b7rdd3df0f984692f35@mail.gmail.com> In-Reply-To: <28c262361001171810w544614b7rdd3df0f984692f35@mail.gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Minchan Kim Cc: KOSAKI Motohiro , LKML , linux-mm , Andrew Morton , Balbir Singh , KAMEZAWA Hiroyuki List-ID: On 01/17/2010 09:10 PM, Minchan Kim wrote: > Absoultely right. I missed that. Thanks. > get_scan_ratio used lru_lock to get reclaim_stat->recent_xxxx. > But, it doesn't used lru_lock to get ap/fp. > > Is it intentional? I think you or Rik know it. :) > I think if we want to get exact value, we have to use lru_lock until > getting ap/fp. > If it isn't, we don't need lru_lock when we get the reclaim_stat->recent_xxxx. > > What do you think about it? This is definately not intentional. Getting race conditions in this code could throw off the statistics by a factor 2. I do not know how serious that would be for the VM or whether (and how quickly) it would self correct. -- All rights reversed. -- 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