From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with SMTP id 645906B0071 for ; Wed, 9 Jun 2010 20:20:30 -0400 (EDT) Received: from m4.gw.fujitsu.co.jp ([10.0.50.74]) by fgwmail6.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id o5A0KR00030260 for (envelope-from kamezawa.hiroyu@jp.fujitsu.com); Thu, 10 Jun 2010 09:20:27 +0900 Received: from smail (m4 [127.0.0.1]) by outgoing.m4.gw.fujitsu.co.jp (Postfix) with ESMTP id 2F99045DE70 for ; Thu, 10 Jun 2010 09:20:27 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (s4.gw.fujitsu.co.jp [10.0.50.94]) by m4.gw.fujitsu.co.jp (Postfix) with ESMTP id D990945DE60 for ; Thu, 10 Jun 2010 09:20:26 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 9DF9E1DB8042 for ; Thu, 10 Jun 2010 09:20:26 +0900 (JST) Received: from m108.s.css.fujitsu.com (m108.s.css.fujitsu.com [10.249.87.108]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 1FC371DB803E for ; Thu, 10 Jun 2010 09:20:26 +0900 (JST) Date: Thu, 10 Jun 2010 09:15:47 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [patch 06/18] oom: avoid sending exiting tasks a SIGKILL Message-Id: <20100610091547.d2c88d4c.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20100609201430.GA8210@redhat.com> References: <20100608202611.GA11284@redhat.com> <20100609162523.GA30464@redhat.com> <20100609201430.GA8210@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Oleg Nesterov Cc: David Rientjes , Andrew Morton , Rik van Riel , Nick Piggin , Balbir Singh , KOSAKI Motohiro , linux-mm@kvack.org List-ID: On Wed, 9 Jun 2010 22:14:30 +0200 Oleg Nesterov wrote: > > in this case since it would > > not be allocating memory without p->mm. > > This thread will not allocate the memory, yes. But its sub-threads can. > And select_bad_process() can constantly return the same (dead) thread P, > badness() inspects ->mm under find_lock_task_mm() which finds the thread > with the valid ->mm. > > OK. Probably this doesn't matter. I don't know if task_in_mem_cgroup(task) > was fixed or not, but currently it also looks at task->mm and thus have > the same boring problem: it is trivial to make the memory-hog process > invisible to oom. Unless I missed something, of course. > HmHm...your concern is that there is a case when mem_cgroup_out_of_memory() can't kill anything ? Now, memcg doesn't return -ENOMEM in usual case. So, it loops until there are some available memory under its limit. Then, if memory_cgroup_out_of_memory() can kill a process in several trial, we'll not have terrible problem. (even if it's slow.) Hmm. What I can't understand is whether there is a case when PF_EXITING thread never exit. If so, we need some care (in memcg?) 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