Re: [PATCH 0/2 -mm] kexec based hibernation -v5

[huang ying]

On 10/20/07, Phillip Susi <psusi@xxxxxxxxxx> wrote:
> Huang, Ying wrote:
> > The hibernation procedure with the patch set is as follow:
> >
> > 1. Boot a kernel A
> >
> > 2. Work under kernel A
> >
> > 3. Kexec another kernel B (crash dump enabled) in kernel A.
> >
> > 4. Save the memory image of kernel A through crash dump (such as "cp
> >    /proc/vmcore ~"). Save the "jump back entry".
>
> Doesn't this also save the memory of kernel B?

The memory area of kernel B is excluded from the elf header of
/proc/vmcore. This is done in kexec-tools (/sbin/kexec) patches.

> > 5. Shutdown or reboot
> >
> >
> > The restore process with the patch set is as follow:
> >
> > 1. Boot a kernel C (crash dump enabled), the memory area used by
> >    kernel C must be a subset of memory area used by kernel B.
>
> Why is a third kernel needed?  Why can't kernel B be used for this as
> well?  In fact, if kernel A has been compiled to be relocatable and
> crash dump enabled, why wouldn't it suffice for all 3 instances?

One kernel can be used for three situation. In fact, I use just one
kernel for testing.

Best Regards,
Huang Ying
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