From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with ESMTP id 69EB28D003B for ; Thu, 21 Apr 2011 00:53:12 -0400 (EDT) Received: from m1.gw.fujitsu.co.jp (unknown [10.0.50.71]) by fgwmail6.fujitsu.co.jp (Postfix) with ESMTP id 29FE43EE0C1 for ; Thu, 21 Apr 2011 13:53:10 +0900 (JST) Received: from smail (m1 [127.0.0.1]) by outgoing.m1.gw.fujitsu.co.jp (Postfix) with ESMTP id 0774C2AEA8F for ; Thu, 21 Apr 2011 13:53:07 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (s1.gw.fujitsu.co.jp [10.0.50.91]) by m1.gw.fujitsu.co.jp (Postfix) with ESMTP id E02512E68C2 for ; Thu, 21 Apr 2011 13:53:06 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id CF1841DB804C for ; Thu, 21 Apr 2011 13:53:06 +0900 (JST) Received: from m105.s.css.fujitsu.com (m105.s.css.fujitsu.com [10.240.81.145]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id 96D2E1DB8042 for ; Thu, 21 Apr 2011 13:53:06 +0900 (JST) Date: Thu, 21 Apr 2011 13:46:27 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH V6 00/10] memcg: per cgroup background reclaim Message-Id: <20110421134627.6a7a6ad5.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: References: <1303185466-2532-1-git-send-email-yinghan@google.com> <20110421025107.GG2333@cmpxchg.org> <20110421130016.3333cb39.kamezawa.hiroyu@jp.fujitsu.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: Ying Han Cc: Johannes Weiner , KOSAKI Motohiro , Minchan Kim , Daisuke Nishimura , Balbir Singh , Tejun Heo , Pavel Emelyanov , Andrew Morton , Li Zefan , Mel Gorman , Christoph Lameter , Rik van Riel , Hugh Dickins , Michal Hocko , Dave Hansen , Zhu Yanhai , linux-mm@kvack.org On Wed, 20 Apr 2011 21:24:07 -0700 Ying Han wrote: > On Wed, Apr 20, 2011 at 9:00 PM, KAMEZAWA Hiroyuki < > kamezawa.hiroyu@jp.fujitsu.com> wrote: > > > > Two watermarks ("high_wmark", "low_wmark") are added to trigger the > > > > background reclaim and stop it. The watermarks are calculated based > > > > on the cgroup's limit_in_bytes. > > > > > > Which brings me to the next issue: making the watermarks configurable. > > > > > > You argued that having them adjustable from userspace is required for > > > overcommitting the hardlimits and per-memcg kswapd reclaim not kicking > > > in in case of global memory pressure. But that is only a problem > > > because global kswapd reclaim is (apart from soft limit reclaim) > > > unaware of memory control groups. > > > > > > I think the much better solution is to make global kswapd memcg aware > > > (with the above mentioned round-robin reclaim scheduler), compared to > > > adding new (and final!) kernel ABI to avoid an internal shortcoming. > > > > > > > I don't think its a good idea to kick kswapd even when free memory is > > enough. > > > > If memcg-kswapd implemted, I'd like to add auto-cgroup for memcg-kswapd and > > limit its cpu usage because it works even when memory is not in-short. > > > > How are we gonna isolate the memcg-kswapd cpu usage under the workqueue > model? > Admin can limit the total cpu usage of memcg-kswapd. So, using private workqueue model seems to make sense. If background-reclaim uses up its cpu share, heavy worker memcg will hit direct reclaim and need to consume its own cpu time. I think it's fair. 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