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Date: Wed, 9 Mar 2011 23:46:57 +1100
From: Anton Blanchard <anton@samba.org>
To: =?ISO-8859-1?B?QW3pcmljbw==?= Wang <xiyou.wangcong@gmail.com>
Subject: Re: [PATCH 1/2] kdump: Allow shrinking of kdump region to be
	overridden
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Hi,

> The crashkernel region is specified via kernel cmdline, so why
> not just drop a failure when it overlaps with RMO region?
> Am I missing something?

Unfortunately a ppc64 kernel requires a chunk of RMO memory. We would
need the ability to specify multiple crashkernel regions - about 32MB
in the RMO and the rest can be anywhere. That sounds pretty fragile for
a user to configure successfully on the cmdline.

Thats why the ppc64 crashkernel region begins mid way through the RMO
region. It means both kernels get a chunk of RMO and we only have to
deal with one crashkernel reservation in all the tools and
documentation.

Anton