Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030343AbWBHFGP (ORCPT ); Wed, 8 Feb 2006 00:06:15 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030344AbWBHFGP (ORCPT ); Wed, 8 Feb 2006 00:06:15 -0500 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:23958 "EHLO ebiederm.dsl.xmission.com") by vger.kernel.org with ESMTP id S1030343AbWBHFGN (ORCPT ); Wed, 8 Feb 2006 00:06:13 -0500 To: Hubertus Franke Cc: Sam Vilain , Rik van Riel , Kirill Korotaev , Linus Torvalds , Andrew Morton , linux-kernel@vger.kernel.org, clg@fr.ibm.com, haveblue@us.ibm.com, greg@kroah.com, alan@lxorguk.ukuu.org.uk, serue@us.ibm.com, arjan@infradead.org, kuznet@ms2.inr.ac.ru, saw@sawoct.com, devel@openvz.org, Dmitry Mishin , Andi Kleen Subject: Re: [PATCH 1/4] Virtualization/containers: introduction References: <43E7C65F.3050609@openvz.org> <43E83E8A.1040704@vilain.net> <43E8D160.4040803@watson.ibm.com> <43E92602.8040403@vilain.net> <43E92AC9.3090308@watson.ibm.com> From: ebiederm@xmission.com (Eric W. Biederman) Date: Tue, 07 Feb 2006 22:03:50 -0700 In-Reply-To: <43E92AC9.3090308@watson.ibm.com> (Hubertus Franke's message of "Tue, 07 Feb 2006 18:18:33 -0500") 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: 1550 Lines: 39 Hubertus Franke writes: > > Agreed.. here are some issued we learned from other projects that had > similar interception points. > > Having a central umbrella object (let's stick to the name container) > is useful, but being the only object through which every access has to > pass may have drawbacks.. > > task->container->pspace->pidmap[offset].page implies potential > cachemisses etc. > > If overhead becomes too large, then we can stick (cache) the pointer > additionally in the task struct. But ofcourse that should be carefully > examined on a per subsystem base... Ok. After talking with the vserver guys on IRC. I think grasp the importance. The key feature is to have a place to put limits and the like for your entire container. Look at all of the non-signal stuff in struct signal for an example. The nested namespaces seem to be just an implementation detail. For OpenVZ having the other namespaces nested may have some importance. I haven't gotten their yet. The task->container->pspace->.... thing feels very awkward to me, and feels like it increases our chance getting a cache miss. So I support the concept of a place to put all of the odd little things like rlimits for containers. But I would like to flatten it in the task_struct if we can. 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/