From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx162.postini.com [74.125.245.162]) by kanga.kvack.org (Postfix) with SMTP id C29696B004D for ; Sun, 22 Apr 2012 20:33:44 -0400 (EDT) Received: from m2.gw.fujitsu.co.jp (unknown [10.0.50.72]) by fgwmail5.fujitsu.co.jp (Postfix) with ESMTP id C828D3EE0C1 for ; Mon, 23 Apr 2012 09:33:42 +0900 (JST) Received: from smail (m2 [127.0.0.1]) by outgoing.m2.gw.fujitsu.co.jp (Postfix) with ESMTP id AD7FA45DE55 for ; Mon, 23 Apr 2012 09:33:42 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (s2.gw.fujitsu.co.jp [10.0.50.92]) by m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 9190345DE52 for ; Mon, 23 Apr 2012 09:33:42 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 827DE1DB8044 for ; Mon, 23 Apr 2012 09:33:42 +0900 (JST) Received: from m105.s.css.fujitsu.com (m105.s.css.fujitsu.com [10.240.81.145]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 2FD801DB8042 for ; Mon, 23 Apr 2012 09:33:42 +0900 (JST) Message-ID: <4F94A2F7.7090803@jp.fujitsu.com> Date: Mon, 23 Apr 2012 09:31:51 +0900 From: KAMEZAWA Hiroyuki MIME-Version: 1.0 Subject: Re: [PATCH V3 1/2] memcg: softlimit reclaim rework References: <1334680682-12430-1-git-send-email-yinghan@google.com> <20120420091731.GE4191@tiehlicka.suse.cz> <20120420231501.GE2536@cmpxchg.org> In-Reply-To: <20120420231501.GE2536@cmpxchg.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Johannes Weiner Cc: Ying Han , Michal Hocko , Mel Gorman , Rik van Riel , Hillf Danton , Hugh Dickins , Dan Magenheimer , Andrew Morton , linux-mm@kvack.org (2012/04/21 8:15), Johannes Weiner wrote: > On Fri, Apr 20, 2012 at 11:22:14AM -0700, Ying Han wrote: >> On Fri, Apr 20, 2012 at 2:17 AM, Michal Hocko wrote: >>> On Tue 17-04-12 09:38:02, Ying Han wrote: >>>> This patch reverts all the existing softlimit reclaim implementations and >>>> instead integrates the softlimit reclaim into existing global reclaim logic. >>>> >>>> The new softlimit reclaim includes the following changes: >>>> >>>> 1. add function should_reclaim_mem_cgroup() >>>> >>>> Add the filter function should_reclaim_mem_cgroup() under the common function >>>> shrink_zone(). The later one is being called both from per-memcg reclaim as >>>> well as global reclaim. >>>> >>>> Today the softlimit takes effect only under global memory pressure. The memcgs >>>> get free run above their softlimit until there is a global memory contention. >>>> This patch doesn't change the semantics. >>> >>> I am not sure I understand but I think it does change the semantics. >>> Previously we looked at a group with the biggest excess and reclaim that >>> group _hierarchically_. >> >> yes, we don't do _hierarchically_ reclaim reclaim in this patch. Hmm, >> that might be what Johannes insists to preserve on the other >> thread.... ? > > Yes, that is exactly what I was talking about all along :-) > > To reiterate, in the case of > > A (soft = 10G) > A1 > A2 > A3 > ... > > global reclaim should go for A, A1, A2, A3, ... when their sum usage > goes above 10G. Regardless of any setting in those subgroups, for > reasons I outlined in the other subthread (basically, allowing > children to override parental settings assumes you trust all children > and their settings to be 'cooperative', which is unprecedented cgroup > semantics, afaics, and we can already see this will make problems in > the future) > > Meanwhile, if you don't want a hierarchical limit, don't set a > hierarchical limit. It's possible to organize the tree such that you > don't need to, and it should not be an unreasonable amount of work to > do so). > I agree. 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