Bug#426035: Please add CONFIG_KEXEC

[Ian Campbell <ijc@hellion.org.uk>]

On Fri, 2007-05-25 at 15:27 -0600, dann frazier wrote:
> Right, but isn't it true that you need a non-relocatable kernel to
> boot and a relocatable kernel to kexec (on x86)? In other words,
> doesn't this require an additional kernel flavor?

If all you want to do is boot a new kernel directly from the current one
(e.g. basic kexec) then you can boot any image at all, including the
current one again. It's basically useful to skip the BIOS post and
reduce downtime. 

If you want kdump, which builds on kexec and allows you to preload a
kernel to be booted when a crash/panic etc occurs then you will need
either a relocatable kernel or one built at a different physical
address[0] so that the existing kernel can be preserved for postmortem
examination.

Personally I find the second use case more useful, but I can see why
people would want the first.

Ian.

[0] which one depends on the kernel rev, I think configurable physical
address was phased out somewhere in 2.6.18-2.6.20 in favour or
relocatable kernel. If relocatable worked properly with kexec then you
wouldn't even need a second image in that case, but I don't think it
currently does.

-- 
Ian Campbell

Life is the childhood of our immortality.
		-- Goethe