From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 19 Jun 2008 19:22:27 +0900 From: KAMEZAWA Hiroyuki Subject: Re: Question : memrlimit cgroup's task_move (2.6.26-rc5-mm3) Message-Id: <20080619192227.972ded64.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20080619122429.138a1d32.kamezawa.hiroyu@jp.fujitsu.com> References: <20080619121435.f868c110.kamezawa.hiroyu@jp.fujitsu.com> <4859CEE7.9030505@linux.vnet.ibm.com> <20080619122429.138a1d32.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 Return-Path: To: KAMEZAWA Hiroyuki Cc: balbir@linux.vnet.ibm.com, "linux-mm@kvack.org" , "menage@google.com" , "containers@lists.osdl.org" List-ID: On Thu, 19 Jun 2008 12:24:29 +0900 KAMEZAWA Hiroyuki wrote: > On Thu, 19 Jun 2008 08:43:43 +0530 > Balbir Singh wrote: > > > > > > I think the charge of the new group goes to minus. right ? > > > (and old group's charge never goes down.) > > > I don't think this is "no problem". > > > > > > What kind of patch is necessary to fix this ? > > > task_attach() should be able to fail in future ? > > > > > > I'm sorry if I misunderstand something or this is already in TODO list. > > > > > > > It's already on the TODO list. Thanks for keeping me reminded about it. > > > Okay, I'm looking foward to see how can_attach and roll-back(if necessary) > is implemnted. > As you know, I'm interested in how to handle failure of task move. > One more thing... Now, charge is done at - vm is inserted (special case?) - vm is expanded (mmap is called, stack growth...) And uncharge is done at - vm is removed (success of munmap) - exit_mm is called (exit of process) But it seems charging at may_expand_vm() is not good. The mmap can fail after may_expand_vm() because of various reason, but charge is already done at may_expand_vm()....and no roll-back. == an easy example of leak in stack growth handling == [root@iridium kamezawa]# cat /opt/cgroup/test/memrlimit.usage_in_bytes 71921664 [root@iridium kamezawa]# ulimit -s 3 [root@iridium kamezawa]# ls Killed [root@iridium kamezawa]# ls Killed [root@iridium kamezawa]# ls Killed [root@iridium kamezawa]# ls Killed [root@iridium kamezawa]# ls Killed [root@iridium kamezawa]# ulimit -s unlimited [root@iridium kamezawa]# cat /opt/cgroup/test/memrlimit.usage_in_bytes 72368128 [root@iridium kamezawa]# == 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/ . Don't email: email@kvack.org