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Date: Wed, 9 Mar 2011 22:21:08 +0800
From: =?utf-8?Q?Am=C3=A9rico?= Wang <xiyou.wangcong@gmail.com>
To: Anton Blanchard <anton@samba.org>
Cc: =?utf-8?Q?Am=C3=A9rico?= Wang <xiyou.wangcong@gmail.com>,
        Mahesh Jagannath Salgaonkar <mahesh@linux.vnet.ibm.com>,
        "Eric W. Biederman" <ebiederm@xmission.com>, akpm@linux-foundation.org,
        kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
        linuxppc-dev@ozlabs.org
Subject: Re: [PATCH 1/2] kdump: Allow shrinking of kdump region to be
 overridden
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References: <20100825002258.GD28360@kryten>
 <m139u37cii.fsf@fess.ebiederm.org>
 <4D771EE6.5050404@linux.vnet.ibm.com>
 <20110309122046.GC16951@cr0.redhat.com>
 <20110309234657.264d3080@kryten>
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On Wed, Mar 09, 2011 at 11:46:57PM +1100, Anton Blanchard wrote:
>
>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.
>

So, when I specify 128M in cmdline, 32M of them are RMO, and the
rest 96M are normal memory? And when I want to free all of them,
actually the 32M RMO will never be freed?

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