From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with SMTP id E9A416B0044 for ; Wed, 7 Jan 2009 23:58:34 -0500 (EST) Received: from m5.gw.fujitsu.co.jp ([10.0.50.75]) by fgwmail5.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id n084wUDE012920 for (envelope-from kamezawa.hiroyu@jp.fujitsu.com); Thu, 8 Jan 2009 13:58:31 +0900 Received: from smail (m5 [127.0.0.1]) by outgoing.m5.gw.fujitsu.co.jp (Postfix) with ESMTP id C854145DE56 for ; Thu, 8 Jan 2009 13:58:30 +0900 (JST) Received: from s5.gw.fujitsu.co.jp (s5.gw.fujitsu.co.jp [10.0.50.95]) by m5.gw.fujitsu.co.jp (Postfix) with ESMTP id 9DE5645DE51 for ; Thu, 8 Jan 2009 13:58:30 +0900 (JST) Received: from s5.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s5.gw.fujitsu.co.jp (Postfix) with ESMTP id 8240D1DB805D for ; Thu, 8 Jan 2009 13:58:30 +0900 (JST) Received: from m106.s.css.fujitsu.com (m106.s.css.fujitsu.com [10.249.87.106]) by s5.gw.fujitsu.co.jp (Postfix) with ESMTP id 352821DB803C for ; Thu, 8 Jan 2009 13:58:30 +0900 (JST) Date: Thu, 8 Jan 2009 13:57:28 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [RFC][PATCH 3/4] Memory controller soft limit organize cgroups Message-Id: <20090108135728.cdb20fe2.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20090108044108.GG7294@balbir.in.ibm.com> References: <20090107184110.18062.41459.sendpatchset@localhost.localdomain> <20090107184128.18062.96016.sendpatchset@localhost.localdomain> <20090108101148.96e688f4.kamezawa.hiroyu@jp.fujitsu.com> <20090108042558.GC7294@balbir.in.ibm.com> <20090108132855.77d3d3d4.kamezawa.hiroyu@jp.fujitsu.com> <20090108044108.GG7294@balbir.in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: balbir@linux.vnet.ibm.com Cc: Andrew Morton , Sudhir Kumar , YAMAMOTO Takashi , Paul Menage , lizf@cn.fujitsu.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, David Rientjes , Pavel Emelianov List-ID: On Thu, 8 Jan 2009 10:11:08 +0530 Balbir Singh wrote: > * KAMEZAWA Hiroyuki [2009-01-08 13:28:55]: > > > On Thu, 8 Jan 2009 09:55:58 +0530 > > Balbir Singh wrote: > > > > > * KAMEZAWA Hiroyuki [2009-01-08 10:11:48]: > > > > Hmm, Could you clarify following ? > > > > > > > > - Usage of memory at insertsion and usage of memory at reclaim is different. > > > > So, this *sorted* order by RB-tree isn't the best order in general. > > > > > > True, but we frequently update the tree at an interval of HZ/4. > > > Updating at every page fault sounded like an overkill and building the > > > entire tree at reclaim is an overkill too. > > > > > "sort" is not necessary. > > If this feature is implemented as background daemon, > > just select the worst one at each iteration is enough. > > OK, definitely an alternative worth considering, but the trade-off is > lazy building (your suggestion), which involves actively seeing the > usage of all cgroups (and if they are large, O(c), c is number of > cgroups can be quite a bit) versus building the tree as and when the > fault occurs and controlled by some interval. > I never think there will be "thousands" of memcg. O(c) is not so bad if it's on background. But usual cost of adding res_counter_soft_limit_excess(&mem->res); is big... This maintainance cost of tree is always necessary even while there are no memory shortage. BTW, - mutex is bad. Can you use mutex while __GFP_WAIT is unset ? - what happens when a big uncharge() occurs and no new charge() happens ? please add + mem = mem_cgroup_get_largest_soft_limit_exceeding_node(); if ( mem is still over soft limit ) do reclaim.... at least. -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/ . Don't email: email@kvack.org