Re: [PATCH 0/2] Kexec jump: The first step to kexec base hibernation

Rafael J. Wysocki
2007-07-12T15:28:33Z

On Thursday, 12 July 2007 15:51, Mark Lord wrote:
> Rafael J. Wysocki wrote:
> > On Thursday, 12 July 2007 08:43, david@lang.hm wrote:
> >> On Wed, 11 Jul 2007, Jeremy Fitzhardinge wrote:
> >>
> >>> Andrew Morton wrote:
> ..
> >> 8. hibernate kernel does syspend-to-ram to put the devices into a known
> >> safe state.
> > Again, the devices should be quiesced rather then suspended in this step.
>
> That's just not possible. The Hibernate kernel will not have all
> of the same device drivers as the mainline kernel. Or at least that's
> what people have previously stated here.

OK, one more problem to solve. :-)

> >>>> This sounds awesome. Am I correct in expecting that ultimately the
> >>>> existing hibernation implementation just goes away and we reuse (and hence
> >>>> strengthen) the existing kexec (and kdump?) infrastructure?
>
> No, not so simple. We still need much of the code to santize devices
> upon wakeup from hibernation. And adding this extra reboot-kernel step
> in the midst of hibernate will double the time it takes (ugh).
>
> Currently, TuxOnIce(suspend2) takes about 10 seconds to suspend my notebook.
> Switching to this new scheme would double that to 10 seconds to boot/probe,
> plus the original 10 seconds to hibernate. Assuming the new implementation
> even comes close to suspend2 speed.

How much RAM is there in your machine?

Greetings,
Rafael

--
"Premature optimization is the root of all evil." - Donald Knuth