From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Hansen Subject: Re: [RFC v13][PATCH 00/14] Kernel based checkpoint/restart Date: Thu, 12 Feb 2009 15:13:53 -0800 Message-ID: <1234480433.30155.226.camel@nimitz> References: <1233076092-8660-1-git-send-email-orenl@cs.columbia.edu> <1234285547.30155.6.camel@nimitz> <20090211141434.dfa1d079.akpm@linux-foundation.org> <1234462282.30155.171.camel@nimitz> <1234467035.3243.538.camel@calx> <1234479457.30155.214.camel@nimitz> <1234479924.3152.13.camel@calx> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1234479924.3152.13.camel@calx> Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Matt Mackall Cc: Ingo Molnar , Andrew Morton , orenl-eQaUEPhvms7ENvBUuze7eA@public.gmane.org, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org, hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org, Thomas Gleixner , Cedric Le Goater , Pavel Emelyanov , Alexey Dobriyan List-Id: linux-api@vger.kernel.org On Thu, 2009-02-12 at 17:05 -0600, Matt Mackall wrote: > On Thu, 2009-02-12 at 14:57 -0800, Dave Hansen wrote: > > > Also, what happens if I checkpoint a process in 2.6.30 and restore it in > > > 2.6.31 which has an expanded idea of what should be restored? Do your > > > file formats handle this sort of forward compatibility or am I > > > restricted to one kernel? > > > > In general, you're restricted to one kernel. But, people have mentioned > > that, if the formats change, we should be able to write in-userspace > > converters for the checkpoint files. > > I mentioned this because it seems like a key use case is upgrading > kernels out from under long-lived applications. The key users as I envision it aren't really kernel hackers who are always running 2.6-next and running radically different kernels from moment to moment. :) Distros are pretty picky about changing things internal to the kernel during errata updates or even service packs. While that can be a pain for some of us developers trying to get features and fixes in, it is a godsend for trying to do something like process migration across an update. My random speculation would be that for things that if a kernel upgrade can be performed with ksplice (http://www.ksplice.com/) -- the original non-fancy version at least -- we can probably migrate across the upgrade. -- Dave -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html