From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751100AbWBBOsY (ORCPT ); Thu, 2 Feb 2006 09:48:24 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751103AbWBBOsY (ORCPT ); Thu, 2 Feb 2006 09:48:24 -0500 Received: from mailhub.sw.ru ([195.214.233.200]:19216 "EHLO relay.sw.ru") by vger.kernel.org with ESMTP id S1751100AbWBBOsX (ORCPT ); Thu, 2 Feb 2006 09:48:23 -0500 Message-ID: <43E21BF3.1080204@sw.ru> Date: Thu, 02 Feb 2006 17:49:23 +0300 From: Kirill Korotaev User-Agent: Mozilla/5.0 (X11; U; Linux i686; ru-RU; rv:1.2.1) Gecko/20030426 X-Accept-Language: ru-ru, en MIME-Version: 1.0 To: Dave Hansen CC: Alan Cox , "Serge E. Hallyn" , Arjan van de Ven , linux-kernel@vger.kernel.org, Hubertus Franke , 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> In-Reply-To: <1137518714.5526.8.camel@localhost.localdomain> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hello all, >>>The virtual pid is different depending on who is asking. So simply >>>storing current->realpid and current->pid isn't helpful, as we would >>>still need to call a function when a pid crosses user->kernel boundary. >> >>This is an obscure, weird piece of functionality for some special case >>usages most of which are going to be eliminated by Xen. I don't see the >>kernel side justification for it at all. > > > At least OpenVZ and vserver want very similar functionality. They're > both working with out-of-tree patch sets. We each want to do subtly > different things with tsk->pid, and task_pid() seemed to be a decent > place to start. OpenVZ has a very similar concept in its pid_task() > function. But our VPID patch is much less intrusive and shorter (thanks to Alexey Kuznetsov). I will send a broken-out patches today CC-ing you. BTW, have you tested it somehow (LTP, etc.)? > Arjan had a very good point last time we posted these: we should > consider getting rid of as many places in the kernel where pids are used > to uniquely identify tasks, and just stick with task_struct pointers. Kirill