From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964893AbWDGTIN (ORCPT ); Fri, 7 Apr 2006 15:08:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964895AbWDGTIN (ORCPT ); Fri, 7 Apr 2006 15:08:13 -0400 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:17601 "EHLO ebiederm.dsl.xmission.com") by vger.kernel.org with ESMTP id S964893AbWDGTIM (ORCPT ); Fri, 7 Apr 2006 15:08:12 -0400 To: "Serge E. Hallyn" Cc: linux-kernel@vger.kernel.org, Kirill Korotaev , herbert@13thfloor.at, devel@openvz.org, sam@vilain.net, xemul@sw.ru, James Morris Subject: Re: [RFC][PATCH 0/5] uts namespaces: Introduction References: <20060407095132.455784000@sergelap> From: ebiederm@xmission.com (Eric W. Biederman) Date: Fri, 07 Apr 2006 13:06:09 -0600 In-Reply-To: <20060407095132.455784000@sergelap> (Serge E. Hallyn's message of "Fri, 7 Apr 2006 13:36:00 -0500 (CDT)") 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 "Serge E. Hallyn" writes: > Introduce utsname namespaces. Instead of a single system_utsname > containing hostname domainname etc, a process can request it's > copy of the uts info to be cloned. The data will be copied from > it's original, but any further changes will not be seen by processes > which are not it's children, and vice versa. > > This is useful, for instance, for vserver/openvz, which can now clone > a new uts namespace for each new virtual server. > > This patchset is based on Kirill Korotaev's Mar 24 submission, taking > comments (in particular from James Morris and Eric Biederman) into > account. > > Some performance results are attached. I was mainly curious whether > it would be worth putting the task_struct->uts_ns pointer inside > a #ifdef CONFIG_UTS_NS. The result show that leaving it in when > CONFIG_UTS_NS=n has negligable performance impact, so that is the > approach this patch takes. Ok. This looks like the best version so far. I like the utsname() function thing to shorten the idiom of current->uts_ns->name. We probably want to introduce utsname() and an init_utsname() before any of the other changes, and then perform the substitutions, before we actually change the code so the patchset can make it through a git-bisect. This will also allows for something that can be put in compat-mac.h for backports of anything that cares. Eric