Re: dynamic oldmem in kdump kernel

Américo Wang
2011-04-08T10:50:06Z

On Thu, Apr 7, 2011 at 9:12 PM, Olaf Hering <olaf@aepfle.de> wrote:
> On Thu, Apr 07, Américo Wang wrote:
>
>> On Thu, Apr 7, 2011 at 5:56 PM, Olaf Hering <olaf@aepfle.de> wrote:
>> > Another issue, slightly related, is memory hotplug.
>> > How is this currently handled for kdump?  Is there code which
>> > automatically reconfigures the kdump kernel with the new memory ranges?
>> >
>>
>> No, the crashkernel memory is reserved during boot, and it is static after
>> that (except you can shrink this memory via /sys).
>
> I meant the overall amount of memory changed by memory hotplug events,
> not the small memory range for the crash kernel itself.
>
>> Kdump isn't aware of memory hotplug.
>
> Ok.  Perhaps there are hotplug events where a helper script could run
> something like 'rckdump restart'.
>

That will not work.

You need to change the kernel to let crashkernel memory to be aware
of memory-hotplug, which means you need to re-search for a suitable
memory range in the newly added memory.

Thanks.