Re: [RFC v6][PATCH 0/9] Kernel based checkpoint/restart

[Dave Hansen <dave-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>]

On Thu, 2008-10-09 at 14:46 +0200, Ingo Molnar wrote:
> * Oren Laadan <orenl-eQaUEPhvms7ENvBUuze7eA@public.gmane.org> wrote:
> 
> > These patches implement basic checkpoint-restart [CR]. This version 
> > (v6) supports basic tasks with simple private memory, and open files 
> > (regular files and directories only). Changes mainly cleanups. See 
> > original announcements below.
> 
> i'm wondering about the following productization aspect: it would be 
> very useful to applications and users if they knew whether it is safe to 
> checkpoint a given app. I.e. whether that app has any state that cannot 
> be stored/restored yet.

Absolutely!

My first inclination was to do this at checkpoint time: detect and tell
users why an app or container can't actually be checkpointed.  But, if I
get you right, you're talking about something that happens more during
the runtime of the app than during the checkpoint.  This sounds like a
wonderful approach to me, and much better than what I was thinking of.

What kind of mechanism do you have in mind?

int sys_remap_file_pages(...)
{
	...
	oh_crap_we_dont_support_this_yet(current);
}

Then the oh_crap..() function sets a task flag or something?

-- Dave