linux-kernel - Re: dynamic oldmem in kdump kernel

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Date:	Fri, 8 Apr 2011 18:49:15 +0800
From:	Américo Wang <xiyou.wangcong@...il.com>
To:	Olaf Hering <olaf@...fle.de>
Cc:	linux-kernel@...r.kernel.org, kexec@...ts.infradead.org
Subject: Re: dynamic oldmem in kdump kernel

On Thu, Apr 7, 2011 at 9:12 PM, Olaf Hering <olaf@...fle.de> wrote:
> On Thu, Apr 07, Américo Wang wrote:
>
>> On Thu, Apr 7, 2011 at 5:56 PM, Olaf Hering <olaf@...fle.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.
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