Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964828AbWBGB70 (ORCPT ); Mon, 6 Feb 2006 20:59:26 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932440AbWBGB70 (ORCPT ); Mon, 6 Feb 2006 20:59:26 -0500 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:58500 "EHLO ebiederm.dsl.xmission.com") by vger.kernel.org with ESMTP id S932439AbWBGB7Z (ORCPT ); Mon, 6 Feb 2006 20:59:25 -0500 To: Cedric Le Goater Cc: Dave Hansen , Kirill Korotaev , Linus Torvalds , Kirill Korotaev , Andrew Morton , Linux Kernel Mailing List , frankeh@watson.ibm.com, greg@kroah.com, alan@lxorguk.ukuu.org.uk, serue@us.ibm.com, arjan@infradead.org, Rik van Riel , Alexey Kuznetsov , Andrey Savochkin , devel@openvz.org, Pavel Emelianov Subject: Re: [RFC][PATCH 1/5] Virtualization/containers: startup References: <43E38BD1.4070707@openvz.org> <43E3915A.2080000@sw.ru> <43E71018.8010104@sw.ru> <1139243874.6189.71.camel@localhost.localdomain> <43E7D077.2090903@fr.ibm.com> From: ebiederm@xmission.com (Eric W. Biederman) Date: Mon, 06 Feb 2006 18:57:05 -0700 In-Reply-To: <43E7D077.2090903@fr.ibm.com> (Cedric Le Goater's message of "Mon, 06 Feb 2006 23:40:55 +0100") 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 Content-Length: 1638 Lines: 40 Cedric Le Goater writes: > Eric W. Biederman wrote: > >> As someone said to me a little bit ago, for migration or checkpointing >> ultimately you have to capture the entire user/kernel interface if >> things are going to work properly. Now if we add this facility to >> the kernel and it is a general purpose facility. It is only a matter >> of time before we need to deal with nested containers. >> >> Not considering the case of having nested containers now is just foolish. >> Maybe we don't have to implement it yet but not considering it is silly. > > That could be restricted. Today, process groups are not nested. Why do you > think nested containers are inevitable ? process groups are a completely different kind of beast. A closer analogy are hierarchical name spaces and mounts. If we didn't need things like waitpid outside one pid namespace to wait for a nested namespace they would be complete disjoint and the implementation would be trivial. >> As far as I can tell there is a very reasonable chance that when we >> are complete there is a very reasonable chance that software suspend >> will just be a special case of migration, done complete in user space. > > Being able to sofware suspend one container among many would be a very > interesting feature to have. That is what checkpointing. And that is simply the persistent form of migration. Eric - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/