Date: Tue, 15 Nov 2005 14:10:03 -0800
From: Mike Kravetz <kravetz@us.ibm.com>
To: linux-mm@kvack.org
Cc: Andy Whitcroft <apw@shadowen.org>, Anton Blanchard <anton@samba.org>,
       linux-kernel@vger.kernel.org
Subject: pfn_to_nid under CONFIG_SPARSEMEM and CONFIG_NUMA
Message-ID: <20051115221003.GA2160@w-mikek2.ibm.com>
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The following code/comment is in <linux/mmzone.h> if SPARSEMEM
and NUMA are configured.

/*
 * These are _only_ used during initialisation, therefore they
 * can use __initdata ...  They could have names to indicate
 * this restriction.
 */
#ifdef CONFIG_NUMA
#define pfn_to_nid              early_pfn_to_nid
#endif

However, pfn_to_nid is certainly used in check_pte_range() mm/mempolicy.c.
I wouldn't be surprised to find more non init time uses if you follow all
the call chains.

On ppc64, early_pfn_to_nid now only uses __initdata.  So, I would expect
policy code that calls check_pte_range to cause serious problems on ppc64.

Any suggestions on how this should really be structured?  I'm thinking
of removing the above definition of pfn_to_nid to force each architecture
to provide a (non init only) version.

-- 
Mike
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