Re: suspend2 merge (was Re: [Suspend2-devel] Re: CFS and suspend2: hang in atomic copy)

From: Pavel Machek
Date: Wed Apr 25 2007 - 16:32:32 EST


> > > > > .. but if the alternative is a feature that just isn't worth it, and
> > > > > likely to not only have its own bugs, but cause bugs elsewhere? (And yes,
> > > > > I believe STD is both of those. There's a reason it's called "STD". Go
> > > > > to google and type "STD" and press "I'm feeling lucky". Google is God).
> > > >
> > > > Is there really no use case for STD?
> [--snip--]
> > > So my objections to STD have nothing to do with saving state and shutting
> > > down. They have everything to do with the fact that it is not - and will
> > > never be - a "suspend", and it shouldn't affect suspend.
> >
> > STD needs to snapshot system, and then it needs devices to be
> > suspended so that snapshot is consistent.
> Not suspended. _Frozen_. In fact don't want any DMA transfers or interrupts
> to take place when we're creating the image. That's all and that's what we're
> doing (or rather, trying to do).

Yep, _frozen_. That's the right word.

> So, the "suspend" and "resume" for the functions being called for that are
> wrong, but then we call them with PMSG_FREEZE. ;-) Still, we could add
> .freeze() and .thaw() callbacks for hibernation just fine. This wouldn't even
> be that difficult ...

It would be ugly big patch I'm afraid.

(cesky, pictures)
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