Re: Re: [PATCH] Remove process freezer from suspend to RAM pathway

Daniel Pittman
2007-07-06T05:45:17Z

Matthew Garrett <mjg59@srcf.ucam.org> writes:
> On Thu, Jul 05, 2007 at 04:09:24PM +0200, Rafael J. Wysocki wrote:
>> On Thursday, 5 July 2007 15:46, Matthew Garrett wrote:
>> > I have a model for STD that avoids the need to freeze the entirity of
>> > userspace, but I need to find some more time to flesh it out.
>>
>> You can just describe it, as far as I'm concerned. :-)
>
> The basic model is that nobody's really described a use-case where we
> actually care about restoring system state. What people want is to be
> able to restore application state. So, arguably, what we want isn't to
> save the entire kernel state and application state in one go because we
> can reconstruct a huge amount of that afterwards.

[...]

> I've mocked up a basic implementation using cryopid, but it's somewhat
> limited by the lack of support for sockets. I'd like to move more of
> the smarts into the kernel (Hurray, checkpointing!) and then see how
> much hardware support ends up horifically broken.

You might want to look at the checkpoint / migration support in the
OpenVZ kernel in relation to this. That does work to dump the state of
a running "virtual environment" complete with applications to disk, move
it to another running kernel and restore the content.

That might, perhaps, help with the prototype of this?

Regards,
Daniel