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From: Chandru <chandru@in.ibm.com>
To: Dave Hansen <dave@linux.vnet.ibm.com>
Subject: Re: 2.6.28-rc9 panics with crashkernel=256M while booting
Date: Mon, 19 Jan 2009 13:41:58 +0530
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	<200901161746.36584.chandru@in.ibm.com>
	<1232128377.27278.69.camel@nimitz>
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Cc: linuxppc-dev@ozlabs.org, Andrew Morton <akpm@linux-foundation.org>,
	Paul Mackerras <paulus@samba.org>, linux-kernel@vger.kernel.org
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On Friday 16 January 2009 23:22:57 Dave Hansen wrote:
> Just looking at it, that calculation is OK.  But, there was one in your
> dmesg that looked a page too long, like page 0x1001 instead of 0x1000.
> I'd find out how that happened.

That is a result of PFN_UP() in reserve_bootmem_node() for which we hit the 
BUG_ON() eventually.   Prior to calling reserve_bootmem_node() we have...

node_ar.end_pfn = node->node_end_pfn = PFN_DOWN(physbase+reserve_size). 

Hence a PFN_UP() will raise the value of 'end'. The kernel has 
CONFIG_PPC_64K_PAGES enabled in the config. 

Chandru