can i "kexec" a running f9 system to a new kernel?

[Tom Horsley]

On Sun, 13 Jul 2008 06:26:06 -0400 (EDT)
"Robert P. J. Day" <rpjday at crashcourse.ca> wrote:

>   quite simply, if i have a running f9 system, can i configure and
> build a new (relocatable, for convenience) kernel and just kexec over
> to it?

I believe the running system needs to have kexec support built
into the kernel, so the more fundamental question is: Does the F9
kernel have kexec? Looking at /boot/config-2.6.25.9-76.fc9.x86_64
on my F9 partition, I see CONFIG_KEXEC=y, so it looks like the
support is there in the kernel, but I don't see any userland
kexec tools to start the reboot process from the command line,
perhaps there is some rpm you need to install to get those?

As far as the actual booting goes, I don't see anything to be
concerned about. The kexec stuff is exactly like a hardware
reboot, it just bypasses the painfully slow process of having
the system BIOS run all the POST nonsense, read the boot loader,
and the boot loader getting the kernel started. It is just
like going directly to the boot loader getting the kernel started.
I'm not even sure why it took so many years for someone to
think of it :-). I think some linux distros have already switched
their "reboot" command to use it.