From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751138AbWBBPP2 (ORCPT ); Thu, 2 Feb 2006 10:15:28 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751139AbWBBPP2 (ORCPT ); Thu, 2 Feb 2006 10:15:28 -0500 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:41390 "EHLO ebiederm.dsl.xmission.com") by vger.kernel.org with ESMTP id S1751138AbWBBPP1 (ORCPT ); Thu, 2 Feb 2006 10:15:27 -0500 To: Kirill Korotaev Cc: Linus Torvalds , Hubertus Franke , Dave Hansen , Greg KH , Alan Cox , "Serge E. Hallyn" , Arjan van de Ven , Linux Kernel Mailing List , Cedric Le Goater Subject: Re: RFC [patch 13/34] PID Virtualization Define new task_pid api References: <20060117143258.150807000@sergelap> <20060117143326.283450000@sergelap> <1137511972.3005.33.camel@laptopd505.fenrus.org> <20060117155600.GF20632@sergelap.austin.ibm.com> <1137513818.14135.23.camel@localhost.localdomain> <1137518714.5526.8.camel@localhost.localdomain> <20060118045518.GB7292@kroah.com> <1137601395.7850.9.camel@localhost.localdomain> <43D14578.6060801@watson.ibm.com> <43E21BD0.6000606@sw.ru> From: ebiederm@xmission.com (Eric W. Biederman) Date: Thu, 02 Feb 2006 08:13:52 -0700 In-Reply-To: <43E21BD0.6000606@sw.ru> (Kirill Korotaev's message of "Thu, 02 Feb 2006 17:48:48 +0300") Message-ID: User-Agent: Gnus/5.1007 (Gnus v5.10.7) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Kirill Korotaev writes: > In fact this is almost what OpenVZ does for half a year, both containers and > VPIDs. > But it is very usefull to see process tree from host system. To be able to use > std tools to manage containers from host (i.e. ps, kill, top, etc.). So it is > much more convinient to have 2 pids. One globally unique, and one for container. There are two issues here. 1) Monitoring. (ps, top etc) 2) Control (kill). For monitoring you might need to patch ps/top a little but it is doable without 2 pids. For kill it is extremely rude to kill processes inside of a nested pid space. There are other solutions to the problem. It is undesireable to make it too easy to communicate through the barrier because then applications may start to take advantage of it and then depend on it and you will have lost the isolation that the container gives you. Eric