From mboxrd@z Thu Jan 1 00:00:00 1970 From: KOSAKI Motohiro Subject: Re: [PATCH] meminfo: show /proc/meminfo base on container's memcg Date: Thu, 31 May 2012 02:23:26 -0400 Message-ID: <4FC70E5E.1010003@gmail.com> References: <1338260214-21919-1-git-send-email-gaofeng@cn.fujitsu.com> <4FC6B68C.2070703@jp.fujitsu.com> <4FC6BC3E.5010807@jp.fujitsu.com> <4FC6C111.2060108@jp.fujitsu.com> <4FC6D881.4090706@jp.fujitsu.com> <4FC70355.70805@jp.fujitsu.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; bh=WqMI1zWzjjXcHARYcJs78dRxi8TmW1eGrr+DpihoQBQ=; b=mWDfm4/XtqB6jHv7RFc4uc7Xv90bbc6mBzj05JwYX7TcADu26IDD5+hcNDAr8Rl2fR BdU0G56jo/SAaDgzRJ7NsZPg7gSbm+U10uAa4kJ1yjR6ZovVJFonVf2m1+SHYcJJKiOo gE08I67fVNOQ10xwZq5GVPb3op9obCc7CBuqsiROuGrdwGjFHnD6J9OahYI/xKUjIoI7 NZ5lkfbDunxA1vf31nSAqQZfxtB+oc2eE/mfDZEe/VVK3SzJ9wtfGfUDHLtc5qQtcuiJ 8SZSU4qJLtYrPZHUs7IsBaUsvd46ZB3saBbpo2ZO2ToSGtFeV/K6BMoti1O/W07X0qhC qXGQ== In-Reply-To: List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Content-Type: text/plain; charset="us-ascii"; format="flowed" To: David Rientjes Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, mhocko-AlSwsSmVLrQ@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, KOSAKI Motohiro , akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org (5/31/12 2:17 AM), David Rientjes wrote: > On Thu, 31 May 2012, Kamezawa Hiroyuki wrote: > >>> The bottomline is that /proc/meminfo is one of many global resource state >>> interfaces and doesn't imply that every thread has access to the full >>> resources. It never has. It's very simple for another thread to consume >>> a large amount of memory as soon as your read() of /proc/meminfo completes >>> and then that information is completely bogus. >> >> Why you need to discuss this here ? We know all information are snapshot. >> > > MemTotal is usually assumed to be static from /proc/meminfo and could now > change radically without notification to the application. > >> Hmm....maybe need to mount cgroup in the container (again) and get an access >> to cgroup >> hierarchy and find the cgroup it belongs to......if it's allowed. > > An application should always know the cgroup that its attached to and be > able to read its state using the command that I gave earlier. No. you don't need why userland folks want namespaces. Even though you don't need namespaces. It doesn't good reason to refuse another use case. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx134.postini.com [74.125.245.134]) by kanga.kvack.org (Postfix) with SMTP id B22EF6B005C for ; Thu, 31 May 2012 02:23:31 -0400 (EDT) Received: by qabg27 with SMTP id g27so2839293qab.14 for ; Wed, 30 May 2012 23:23:30 -0700 (PDT) Message-ID: <4FC70E5E.1010003@gmail.com> Date: Thu, 31 May 2012 02:23:26 -0400 From: KOSAKI Motohiro MIME-Version: 1.0 Subject: Re: [PATCH] meminfo: show /proc/meminfo base on container's memcg References: <1338260214-21919-1-git-send-email-gaofeng@cn.fujitsu.com> <4FC6B68C.2070703@jp.fujitsu.com> <4FC6BC3E.5010807@jp.fujitsu.com> <4FC6C111.2060108@jp.fujitsu.com> <4FC6D881.4090706@jp.fujitsu.com> <4FC70355.70805@jp.fujitsu.com> 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: David Rientjes Cc: Kamezawa Hiroyuki , KOSAKI Motohiro , Gao feng , hannes@cmpxchg.org, mhocko@suse.cz, bsingharora@gmail.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org, containers@lists.linux-foundation.org (5/31/12 2:17 AM), David Rientjes wrote: > On Thu, 31 May 2012, Kamezawa Hiroyuki wrote: > >>> The bottomline is that /proc/meminfo is one of many global resource state >>> interfaces and doesn't imply that every thread has access to the full >>> resources. It never has. It's very simple for another thread to consume >>> a large amount of memory as soon as your read() of /proc/meminfo completes >>> and then that information is completely bogus. >> >> Why you need to discuss this here ? We know all information are snapshot. >> > > MemTotal is usually assumed to be static from /proc/meminfo and could now > change radically without notification to the application. > >> Hmm....maybe need to mount cgroup in the container (again) and get an access >> to cgroup >> hierarchy and find the cgroup it belongs to......if it's allowed. > > An application should always know the cgroup that its attached to and be > able to read its state using the command that I gave earlier. No. you don't need why userland folks want namespaces. Even though you don't need namespaces. It doesn't good reason to refuse another use case. -- 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 S1757252Ab2EaGXd (ORCPT ); Thu, 31 May 2012 02:23:33 -0400 Received: from mail-qc0-f174.google.com ([209.85.216.174]:35568 "EHLO mail-qc0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753580Ab2EaGXb (ORCPT ); Thu, 31 May 2012 02:23:31 -0400 Message-ID: <4FC70E5E.1010003@gmail.com> Date: Thu, 31 May 2012 02:23:26 -0400 From: KOSAKI Motohiro User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7; rv:12.0) Gecko/20120428 Thunderbird/12.0.1 MIME-Version: 1.0 To: David Rientjes CC: Kamezawa Hiroyuki , KOSAKI Motohiro , Gao feng , hannes@cmpxchg.org, mhocko@suse.cz, bsingharora@gmail.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org, containers@lists.linux-foundation.org Subject: Re: [PATCH] meminfo: show /proc/meminfo base on container's memcg References: <1338260214-21919-1-git-send-email-gaofeng@cn.fujitsu.com> <4FC6B68C.2070703@jp.fujitsu.com> <4FC6BC3E.5010807@jp.fujitsu.com> <4FC6C111.2060108@jp.fujitsu.com> <4FC6D881.4090706@jp.fujitsu.com> <4FC70355.70805@jp.fujitsu.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (5/31/12 2:17 AM), David Rientjes wrote: > On Thu, 31 May 2012, Kamezawa Hiroyuki wrote: > >>> The bottomline is that /proc/meminfo is one of many global resource state >>> interfaces and doesn't imply that every thread has access to the full >>> resources. It never has. It's very simple for another thread to consume >>> a large amount of memory as soon as your read() of /proc/meminfo completes >>> and then that information is completely bogus. >> >> Why you need to discuss this here ? We know all information are snapshot. >> > > MemTotal is usually assumed to be static from /proc/meminfo and could now > change radically without notification to the application. > >> Hmm....maybe need to mount cgroup in the container (again) and get an access >> to cgroup >> hierarchy and find the cgroup it belongs to......if it's allowed. > > An application should always know the cgroup that its attached to and be > able to read its state using the command that I gave earlier. No. you don't need why userland folks want namespaces. Even though you don't need namespaces. It doesn't good reason to refuse another use case.