From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754649AbZBXHvy (ORCPT ); Tue, 24 Feb 2009 02:51:54 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751664AbZBXHvq (ORCPT ); Tue, 24 Feb 2009 02:51:46 -0500 Received: from e9.ny.us.ibm.com ([32.97.182.139]:39388 "EHLO e9.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751307AbZBXHvp (ORCPT ); Tue, 24 Feb 2009 02:51:45 -0500 Subject: Re: Banning checkpoint (was: Re: What can OpenVZ do?) From: Dave Hansen To: Alexey Dobriyan Cc: Ingo Molnar , Nathan Lynch , linux-api@vger.kernel.org, containers@lists.linux-foundation.org, mpm@selenic.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, viro@zeniv.linux.org.uk, hpa@zytor.com, Andrew Morton , torvalds@linux-foundation.org, tglx@linutronix.de, xemul@openvz.org In-Reply-To: <20090224044752.GB3202@x200.localdomain> References: <20090217222319.GA10546@elte.hu> <1234909849.4816.9.camel@nimitz> <20090218003217.GB25856@elte.hu> <1234917639.4816.12.camel@nimitz> <20090218051123.GA9367@x200.localdomain> <20090218181644.GD19995@elte.hu> <1234992447.26788.12.camel@nimitz> <20090218231545.GA17524@elte.hu> <20090219190637.GA4846@x200.localdomain> <1235070714.26788.56.camel@nimitz> <20090224044752.GB3202@x200.localdomain> Content-Type: text/plain Date: Mon, 23 Feb 2009 21:11:25 -0800 Message-Id: <1235452285.26788.226.camel@nimitz> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2009-02-24 at 07:47 +0300, Alexey Dobriyan wrote: > > I think what I posted is a decent compromise. It gets you those > > warnings at runtime and is a one-way trip for any given process. But, > > it does detect in certain cases (fork() and unshare(FILES)) when it is > > safe to make the trip back to the "I'm checkpointable" state again. > > "Checkpointable" is not even per-process property. > > Imagine, set of SAs (struct xfrm_state) and SPDs (struct xfrm_policy). > They are a) per-netns, b) persistent. > > You can hook into socketcalls to mark process as uncheckpointable, > but since SAs and SPDs are persistent, original process already exited. > You're going to walk every process with same netns as SA adder and mark > it as uncheckpointable. Definitely doable, but ugly, isn't it? > > Same for iptable rules. > > "Checkpointable" is container property, OK? Ideally, I completely agree. But, we don't currently have a concept of a true container in the kernel. Do you have any suggestions for any current objects that we could use in its place for a while? -- Dave