Messages in this thread | | | Subject | Re: [RFC][PATCH 1/4] checkpoint-restart: general infrastructure | From | Dave Hansen <> | Date | Sat, 09 Aug 2008 06:39:25 -0700 |
| |
On Sat, 2008-08-09 at 08:37 +0200, Arnd Bergmann wrote: > On Saturday 09 August 2008, Dave Hansen wrote: > > On Sat, 2008-08-09 at 00:39 +0200, Arnd Bergmann wrote: > > > The main problem I see with that would be atomicity: If you want multiple > > > processes to keep interacting with each other, you need to save them at > > > the same point in time, which gets harder as you split your interface into > > > more than a single file descriptor. > > > > It could take ages to write out a checkpoint even to a single fd, so I > > suspect we'd have the exact same kinds of issues either way. > > I guess either way, you have to SIGSTOP (or similar) all the tasks you want > to checkpoint atomically before you start saving the contents. > If you use a single fd, you can do that under the covers, when using a > more complex file system, it seems more logical to require an explicit > interface for this.
Oh, we're already working on patches to the freezer code to do this for us. There's a branch in here from Matt H. that's doing just that:
http://git.kernel.org/?p=linux/kernel/git/daveh/linux-2.6-next-lxc.git;a=shortlog
-- Dave
| |