From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx168.postini.com [74.125.245.168]) by kanga.kvack.org (Postfix) with SMTP id E7A936B00C0 for ; Mon, 11 Jun 2012 03:08:14 -0400 (EDT) Received: from m1.gw.fujitsu.co.jp (unknown [10.0.50.71]) by fgwmail6.fujitsu.co.jp (Postfix) with ESMTP id 1126D3EE0B6 for ; Mon, 11 Jun 2012 16:08:13 +0900 (JST) Received: from smail (m1 [127.0.0.1]) by outgoing.m1.gw.fujitsu.co.jp (Postfix) with ESMTP id E8AC845DE5A for ; Mon, 11 Jun 2012 16:08:12 +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 CCBA445DE56 for ; Mon, 11 Jun 2012 16:08:12 +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 B99151DB8051 for ; Mon, 11 Jun 2012 16:08:12 +0900 (JST) Received: from ml14.s.css.fujitsu.com (ml14.s.css.fujitsu.com [10.240.81.134]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id 7447F1DB8042 for ; Mon, 11 Jun 2012 16:08:12 +0900 (JST) Message-ID: <4FD598C2.8020709@jp.fujitsu.com> Date: Mon, 11 Jun 2012 16:05:38 +0900 From: Kamezawa Hiroyuki MIME-Version: 1.0 Subject: Re: [PATCH] memcg: fix use_hierarchy css_is_ancestor oops regression References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Hugh Dickins Cc: Andrew Morton , Johannes Weiner , Konstantin Khlebnikov , Michal Hocko , linux-kernel@vger.kernel.org, linux-mm@kvack.org (2012/06/11 3:54), Hugh Dickins wrote: > If use_hierarchy is set, reclaim testing soon oopses in css_is_ancestor() > called from __mem_cgroup_same_or_subtree() called from page_referenced(): > when processes are exiting, it's easy for mm_match_cgroup() to pass along > a NULL memcg coming from a NULL mm->owner. > > Check for that in __mem_cgroup_same_or_subtree(). Return true or false? > False because we cannot know if it was in the hierarchy, but also false > because it's better not to count a reference from an exiting process. > > Signed-off-by: Hugh Dickins Acked-by: KAMEZAWA Hiroyuki -- 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