From mboxrd@z Thu Jan 1 00:00:00 1970 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH v3 1/6] memcg: fix error code in hugetlb_force_memcg_empty() Date: Mon, 14 May 2012 10:07:34 +0900 Message-ID: <4FB05AD6.1090400@jp.fujitsu.com> References: <4FACDED0.3020400@jp.fujitsu.com> <4FACDFAE.5050808@jp.fujitsu.com> <20120511141754.e0719c26.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20120511141754.e0719c26.akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Andrew Morton Cc: "linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org" , "cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Michal Hocko , Johannes Weiner , Frederic Weisbecker , Han Ying , Glauber Costa , Tejun Heo , "Aneesh Kumar K.V" , Hiroyuki Kamezawa , Linux Kernel (2012/05/12 6:17), Andrew Morton wrote: > On Fri, 11 May 2012 18:45:18 +0900 > KAMEZAWA Hiroyuki wrote: > >> The conditions are handled as -EBUSY, _now_. > > The changelog is poor. I rewrote it to > > : hugetlb_force_memcg_empty() incorrectly returns 0 (success) when the > : cgroup is found to be busy. Return -EBUSY instead. > > But it still doesn't tell us the end-user-visible effects of the bug. > It should. > Ah, sorry. How about this ? The force_empty interface allows to make the memcg only when the cgroup doesn't include any tasks. # echo 0 > /cgroup/xxxx/memory.force_empty If cgroup isn't empty, force_empty does nothing and retruns -EBUSY in usual memcg, memcontrol.c. But hugetlb implementation has inconsitency with it and returns 0 and do nothing. Fix it to return -EBUSY. Thanks, -Kame From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx118.postini.com [74.125.245.118]) by kanga.kvack.org (Postfix) with SMTP id C3A546B00E7 for ; Sun, 13 May 2012 21:09:34 -0400 (EDT) Received: from m3.gw.fujitsu.co.jp (unknown [10.0.50.73]) by fgwmail5.fujitsu.co.jp (Postfix) with ESMTP id 84EE33EE0C3 for ; Mon, 14 May 2012 10:09:32 +0900 (JST) Received: from smail (m3 [127.0.0.1]) by outgoing.m3.gw.fujitsu.co.jp (Postfix) with ESMTP id 5D59045DEB6 for ; Mon, 14 May 2012 10:09:32 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (s3.gw.fujitsu.co.jp [10.0.50.93]) by m3.gw.fujitsu.co.jp (Postfix) with ESMTP id 340BD45DEB4 for ; Mon, 14 May 2012 10:09:32 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id 22B291DB803F for ; Mon, 14 May 2012 10:09:32 +0900 (JST) Received: from m1000.s.css.fujitsu.com (m1000.s.css.fujitsu.com [10.240.81.136]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id C0203E18004 for ; Mon, 14 May 2012 10:09:31 +0900 (JST) Message-ID: <4FB05AD6.1090400@jp.fujitsu.com> Date: Mon, 14 May 2012 10:07:34 +0900 From: KAMEZAWA Hiroyuki MIME-Version: 1.0 Subject: Re: [PATCH v3 1/6] memcg: fix error code in hugetlb_force_memcg_empty() References: <4FACDED0.3020400@jp.fujitsu.com> <4FACDFAE.5050808@jp.fujitsu.com> <20120511141754.e0719c26.akpm@linux-foundation.org> In-Reply-To: <20120511141754.e0719c26.akpm@linux-foundation.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: "linux-mm@kvack.org" , "cgroups@vger.kernel.org" , Michal Hocko , Johannes Weiner , Frederic Weisbecker , Han Ying , Glauber Costa , Tejun Heo , "Aneesh Kumar K.V" , Hiroyuki Kamezawa , Linux Kernel (2012/05/12 6:17), Andrew Morton wrote: > On Fri, 11 May 2012 18:45:18 +0900 > KAMEZAWA Hiroyuki wrote: > >> The conditions are handled as -EBUSY, _now_. > > The changelog is poor. I rewrote it to > > : hugetlb_force_memcg_empty() incorrectly returns 0 (success) when the > : cgroup is found to be busy. Return -EBUSY instead. > > But it still doesn't tell us the end-user-visible effects of the bug. > It should. > Ah, sorry. How about this ? The force_empty interface allows to make the memcg only when the cgroup doesn't include any tasks. # echo 0 > /cgroup/xxxx/memory.force_empty If cgroup isn't empty, force_empty does nothing and retruns -EBUSY in usual memcg, memcontrol.c. But hugetlb implementation has inconsitency with it and returns 0 and do nothing. Fix it to return -EBUSY. 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753925Ab2ENBJf (ORCPT ); Sun, 13 May 2012 21:09:35 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:51157 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753377Ab2ENBJe (ORCPT ); Sun, 13 May 2012 21:09:34 -0400 X-SecurityPolicyCheck: OK by SHieldMailChecker v1.7.4 Message-ID: <4FB05AD6.1090400@jp.fujitsu.com> Date: Mon, 14 May 2012 10:07:34 +0900 From: KAMEZAWA Hiroyuki User-Agent: Mozilla/5.0 (Windows NT 6.0; rv:12.0) Gecko/20120428 Thunderbird/12.0.1 MIME-Version: 1.0 To: Andrew Morton CC: "linux-mm@kvack.org" , "cgroups@vger.kernel.org" , Michal Hocko , Johannes Weiner , Frederic Weisbecker , Han Ying , Glauber Costa , Tejun Heo , "Aneesh Kumar K.V" , Hiroyuki Kamezawa , Linux Kernel Subject: Re: [PATCH v3 1/6] memcg: fix error code in hugetlb_force_memcg_empty() References: <4FACDED0.3020400@jp.fujitsu.com> <4FACDFAE.5050808@jp.fujitsu.com> <20120511141754.e0719c26.akpm@linux-foundation.org> In-Reply-To: <20120511141754.e0719c26.akpm@linux-foundation.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (2012/05/12 6:17), Andrew Morton wrote: > On Fri, 11 May 2012 18:45:18 +0900 > KAMEZAWA Hiroyuki wrote: > >> The conditions are handled as -EBUSY, _now_. > > The changelog is poor. I rewrote it to > > : hugetlb_force_memcg_empty() incorrectly returns 0 (success) when the > : cgroup is found to be busy. Return -EBUSY instead. > > But it still doesn't tell us the end-user-visible effects of the bug. > It should. > Ah, sorry. How about this ? The force_empty interface allows to make the memcg only when the cgroup doesn't include any tasks. # echo 0 > /cgroup/xxxx/memory.force_empty If cgroup isn't empty, force_empty does nothing and retruns -EBUSY in usual memcg, memcontrol.c. But hugetlb implementation has inconsitency with it and returns 0 and do nothing. Fix it to return -EBUSY. Thanks, -Kame