From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with ESMTP id 414CC6B0099 for ; Fri, 28 Aug 2009 03:20:13 -0400 (EDT) Received: from d28relay01.in.ibm.com (d28relay01.in.ibm.com [9.184.220.58]) by e28smtp09.in.ibm.com (8.14.3/8.13.1) with ESMTP id n7S7JYip019779 for ; Fri, 28 Aug 2009 12:49:34 +0530 Received: from d28av02.in.ibm.com (d28av02.in.ibm.com [9.184.220.64]) by d28relay01.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id n7S7KApa999558 for ; Fri, 28 Aug 2009 12:50:11 +0530 Received: from d28av02.in.ibm.com (loopback [127.0.0.1]) by d28av02.in.ibm.com (8.14.3/8.13.1/NCO v10.0 AVout) with ESMTP id n7S7K9Pt003211 for ; Fri, 28 Aug 2009 17:20:10 +1000 Date: Fri, 28 Aug 2009 12:50:08 +0530 From: Balbir Singh Subject: Re: [RFC][PATCH 1/5] memcg: change for softlimit. Message-ID: <20090828072007.GH4889@balbir.in.ibm.com> Reply-To: balbir@linux.vnet.ibm.com References: <20090828132015.10a42e40.kamezawa.hiroyu@jp.fujitsu.com> <20090828132321.e4a497bb.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20090828132321.e4a497bb.kamezawa.hiroyu@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org To: KAMEZAWA Hiroyuki Cc: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "nishimura@mxp.nes.nec.co.jp" List-ID: * KAMEZAWA Hiroyuki [2009-08-28 13:23:21]: > This patch tries to modify softlimit handling in memcg/res_counter. > There are 2 reasons in general. > > 1. soft_limit can use only against sub-hierarchy root. > Because softlimit tree is sorted by usage, putting prural groups > under hierarchy (which shares usage) will just adds noise and unnecessary > mess. This patch limits softlimit feature only to hierarchy root. > This will make softlimit-tree maintainance better. > > 2. In these days, it's reported that res_counter can be bottleneck in > massively parallel enviroment. We need to reduce jobs under spinlock. > The reason we check softlimit at res_counter_charge() is that any member > in hierarchy can have softlimit. > But by chages in "1", only hierarchy root has soft_limit. We can omit > hierarchical check in res_counter. > > After this patch, soft limit is avaliable only for root of sub-hierarchy. > (Anyway, softlimit for hierarchy children just makes users confused, hard-to-use) > I need some time to digest this change, if the root is a hiearchy root then only root can support soft limits? I think the change makes it harder to use soft limits. Please help me understand better. -- Balbir -- 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