From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx176.postini.com [74.125.245.176]) by kanga.kvack.org (Postfix) with SMTP id 537BD6B002C for ; Thu, 8 Mar 2012 20:58:41 -0500 (EST) Received: from m1.gw.fujitsu.co.jp (unknown [10.0.50.71]) by fgwmail6.fujitsu.co.jp (Postfix) with ESMTP id C11433EE0C0 for ; Fri, 9 Mar 2012 10:58:39 +0900 (JST) Received: from smail (m1 [127.0.0.1]) by outgoing.m1.gw.fujitsu.co.jp (Postfix) with ESMTP id A71E545DE64 for ; Fri, 9 Mar 2012 10:58:39 +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 8E6C545DE5D for ; Fri, 9 Mar 2012 10:58:39 +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 7B09E1DB8053 for ; Fri, 9 Mar 2012 10:58:39 +0900 (JST) Received: from m106.s.css.fujitsu.com (m106.s.css.fujitsu.com [10.240.81.146]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id 2AAEE1DB804A for ; Fri, 9 Mar 2012 10:58:39 +0900 (JST) Date: Fri, 9 Mar 2012 10:57:06 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [patch] mm, memcg: do not allow tasks to be attached with zero limit Message-Id: <20120309105706.4001646a.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20120308173818.ae5f621b.akpm@linux-foundation.org> References: <20120308122951.2988ec4e.akpm@linux-foundation.org> <20120309102255.bbf94164.kamezawa.hiroyu@jp.fujitsu.com> <20120308173818.ae5f621b.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: David Rientjes , Johannes Weiner , Michal Hocko , Balbir Singh , cgroups@vger.kernel.org, linux-mm@kvack.org On Thu, 8 Mar 2012 17:38:18 -0800 Andrew Morton wrote: > On Fri, 9 Mar 2012 10:22:55 +0900 KAMEZAWA Hiroyuki wrote: > > > On Thu, 8 Mar 2012 12:29:51 -0800 > > Andrew Morton wrote: > > > > > On Wed, 7 Mar 2012 19:14:49 -0800 (PST) > > > David Rientjes wrote: > > > > > > > This patch prevents tasks from being attached to a memcg if there is a > > > > hard limit of zero. > > > > > > We're talking about the memcg's limit_in_bytes here, yes? > > > > > > > Additionally, the hard limit may not be changed to > > > > zero if there are tasks attached. > > > > > > hm, well... why? That would be user error, wouldn't it? What is > > > special about limit_in_bytes=0? The memcg will also be unviable if > > > limit_in_bytes=1, but we permit that. > > > > > > IOW, confused. > > > > > Ah, yes. limit_in_bytes < some small size can cause the same trouble. > > Hmm... should we have configurable min_limit_in_bytes as sysctl or root memcg's > > attaribute.. ? > > Why do *anything*? If the operator chose an irrational configuration > then things won't work correctly and the operator will then fix the > configuration? > Because the result of 'error operaton' is SIGKILL to a task, which may be owned by very importang customer of hosting service. Isn't this severe punishment for error operation ? Considering again, I have 2 thoughts. - it should be guarded by MiddleWare, it's not kernel job ! - memcg should be more easy-to-use, friendly to users. If the result is just an error as EINVAL or EBUSY, I may not be nervous.... 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