From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with ESMTP id 1E8476B016A for ; Wed, 31 Aug 2011 20:17:05 -0400 (EDT) Received: from m3.gw.fujitsu.co.jp (unknown [10.0.50.73]) by fgwmail6.fujitsu.co.jp (Postfix) with ESMTP id 05F343EE0B6 for ; Thu, 1 Sep 2011 09:17:02 +0900 (JST) Received: from smail (m3 [127.0.0.1]) by outgoing.m3.gw.fujitsu.co.jp (Postfix) with ESMTP id E130745DEB3 for ; Thu, 1 Sep 2011 09:17:01 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (s3.gw.fujitsu.co.jp [10.0.50.93]) by m3.gw.fujitsu.co.jp (Postfix) with ESMTP id C6FDF45DEA6 for ; Thu, 1 Sep 2011 09:17:01 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id B86951DB803C for ; Thu, 1 Sep 2011 09:17:01 +0900 (JST) Received: from ml13.s.css.fujitsu.com (ml13.s.css.fujitsu.com [10.240.81.133]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id 837431DB8037 for ; Thu, 1 Sep 2011 09:17:01 +0900 (JST) Date: Thu, 1 Sep 2011 09:09:31 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [patch] memcg: skip scanning active lists based on individual size Message-Id: <20110901090931.c0721216.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: References: <20110831090850.GA27345@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim Cc: Johannes Weiner , Andrew Morton , Rik van Riel , KOSAKI Motohiro , Daisuke Nishimura , Balbir Singh , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Wed, 31 Aug 2011 19:13:34 +0900 Minchan Kim wrote: > On Wed, Aug 31, 2011 at 6:08 PM, Johannes Weiner wrote: > > Reclaim decides to skip scanning an active list when the corresponding > > inactive list is above a certain size in comparison to leave the > > assumed working set alone while there are still enough reclaim > > candidates around. > > > > The memcg implementation of comparing those lists instead reports > > whether the whole memcg is low on the requested type of inactive > > pages, considering all nodes and zones. > > > > This can lead to an oversized active list not being scanned because of > > the state of the other lists in the memcg, as well as an active list > > being scanned while its corresponding inactive list has enough pages. > > > > Not only is this wrong, it's also a scalability hazard, because the > > global memory state over all nodes and zones has to be gathered for > > each memcg and zone scanned. > > > > Make these calculations purely based on the size of the two LRU lists > > that are actually affected by the outcome of the decision. > > > > Signed-off-by: Johannes Weiner > > Cc: Rik van Riel > > Cc: KOSAKI Motohiro > > Cc: KAMEZAWA Hiroyuki > > Cc: Daisuke Nishimura > > Cc: Balbir Singh > > Reviewed-by: Minchan Kim > > I can't understand why memcg is designed for considering all nodes and zones. > Is it a mistake or on purpose? It's purpose. memcg just takes care of the amount of pages. Them, any performance numbers ? But, hmm, this change may be good for softlimit and your work. I'll ack when you add performance numbers in changelog. Thanks, -Kame -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org