Re: Banning checkpoint (was: Re: What can OpenVZ do?)

From: Dave Hansen
Date: Tue Feb 24 2009 - 02:51:54 EST


On Tue, 2009-02-24 at 07:47 +0300, Alexey Dobriyan wrote:
> > I think what I posted is a decent compromise. It gets you those
> > warnings at runtime and is a one-way trip for any given process. But,
> > it does detect in certain cases (fork() and unshare(FILES)) when it is
> > safe to make the trip back to the "I'm checkpointable" state again.
>
> "Checkpointable" is not even per-process property.
>
> Imagine, set of SAs (struct xfrm_state) and SPDs (struct xfrm_policy).
> They are a) per-netns, b) persistent.
>
> You can hook into socketcalls to mark process as uncheckpointable,
> but since SAs and SPDs are persistent, original process already exited.
> You're going to walk every process with same netns as SA adder and mark
> it as uncheckpointable. Definitely doable, but ugly, isn't it?
>
> Same for iptable rules.
>
> "Checkpointable" is container property, OK?

Ideally, I completely agree.

But, we don't currently have a concept of a true container in the
kernel. Do you have any suggestions for any current objects that we
could use in its place for a while?

-- Dave

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