From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758858AbZBZWKm (ORCPT ); Thu, 26 Feb 2009 17:10:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753285AbZBZWKc (ORCPT ); Thu, 26 Feb 2009 17:10:32 -0500 Received: from mail-fx0-f176.google.com ([209.85.220.176]:51215 "EHLO mail-fx0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753281AbZBZWKb (ORCPT ); Thu, 26 Feb 2009 17:10:31 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=l6lvtEMQmleWAhG2E4Ok+X5z1ikTbKLcXRFN8UxzcZDaWzCQPWJ4uFykZ1uikf6NJh 0SU/ZIKs1Jyrax7pkLl3bQGi+RKAa+IVwXWIyW/W4l1CUfodCM/kdtZzmFodWfsrqkWU ejmbIauibWSh0HxdbLqO97nGDYxTA+IaPBFpA= Date: Fri, 27 Feb 2009 01:17:09 +0300 From: Alexey Dobriyan To: Greg Kurz Cc: Ingo Molnar , linux-api@vger.kernel.org, containers@lists.linux-foundation.org, hpa@zytor.com, linux-kernel@vger.kernel.org, Dave Hansen , linux-mm@kvack.org, viro@zeniv.linux.org.uk, mpm@selenic.com, Andrew Morton , torvalds@linux-foundation.org, tglx@linutronix.de, xemul@openvz.org Subject: Re: How much of a mess does OpenVZ make? ;) Was: What can OpenVZ do? Message-ID: <20090226221709.GA2924@x200.localdomain> References: <20090211141434.dfa1d079.akpm@linux-foundation.org> <1234462282.30155.171.camel@nimitz> <1234467035.3243.538.camel@calx> <20090212114207.e1c2de82.akpm@linux-foundation.org> <1234475483.30155.194.camel@nimitz> <20090212141014.2cd3d54d.akpm@linux-foundation.org> <1234479845.30155.220.camel@nimitz> <20090226162755.GB1456@x200.localdomain> <20090226173302.GB29439@elte.hu> <1235673016.5877.62.camel@bahia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1235673016.5877.62.camel@bahia> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Feb 26, 2009 at 07:30:16PM +0100, Greg Kurz wrote: > On Thu, 2009-02-26 at 18:33 +0100, Ingo Molnar wrote: > > I think the main question is: will we ever find ourselves in the > > future saying that "C/R sucks, nobody but a small minority uses > > it, wish we had never merged it"? I think the likelyhood of that > > is very low. I think the current OpenVZ stuff already looks very > > We've been maintaining for some years now a C/R middleware with only a > few hooks in the kernel. Our strategy is to leverage existing kernel > paths as they do most of the work right. > > Most of the checkpoint is performed from userspace, using regular > syscalls in a signal handler or /proc parsing. Restart is a bit trickier > and needs some kernel support to bypass syscall checks and enforce a > specific id for a resource. At the end, we support C/R and live > migration of networking apps (websphere application server for example). > > >From our experience, we can tell: > > Pros: mostly not-so-tricky userland code, independent from kernel > internals > Cons: sub-optimal for some resources How do you restore struct task_struct::did_exec ?