[PATCH] remove non-DISCONTIG use of pgdat->node_mem_map

This patch effectively eliminates direct use of pgdat->node_mem_map outside
of the DISCONTIG code.  On a flat memory system, these fields aren't
currently used, neither are they on a sparsemem system.

There was also a node_mem_map(nid) macro on many architectures.  Its use
along with the use of ->node_mem_map itself was not consistent.  It has
been removed in favor of two new, more explicit, arch-independent macros:

	pgdat_page_nr(pgdat, pagenr)
	nid_page_nr(nid, pagenr)

I called them "pgdat" and "nid" because we overload the term "node" to mean
"NUMA node", "DISCONTIG node" or "pg_data_t" in very confusing ways.  I
believe the newer names are much clearer.

These macros can be overridden in the sparsemem case with a theoretically
slower operation using node_start_pfn and pfn_to_page(), instead.  We could
make this the only behavior if people want, but I don't want to change too
much at once.  One thing at a time.

This patch removes more code than it adds.

Compile tested on alpha, alpha discontig, arm, arm-discontig, i386, i386
generic, NUMAQ, Summit, ppc64, ppc64 discontig, and x86_64.  Full list
here: http://sr71.net/patches/2.6.12/2.6.12-rc1-mhp2/configs/

Boot tested on NUMAQ, x86 SMP and ppc64 power4/5 LPARs.

Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Martin J. Bligh <mbligh@aracnet.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 5 insertions, 4 deletions

diff --git a/arch/ia64/mm/discontig.c b/arch/ia64/mm/discontig.c
index c0071092939..f3fd528ead3 100644
--- a/arch/ia64/mm/discontig.c
+++ b/arch/ia64/mm/discontig.c
@@ -560,14 +560,15 @@ void show_mem(void)
 		int shared = 0, cached = 0, reserved = 0;
 		printk("Node ID: %d\n", pgdat->node_id);
 		for(i = 0; i < pgdat->node_spanned_pages; i++) {
+			struct page *page = pgdat_page_nr(pgdat, i);
 			if (!ia64_pfn_valid(pgdat->node_start_pfn+i))
 				continue;
-			if (PageReserved(pgdat->node_mem_map+i))
+			if (PageReserved(page))
 				reserved++;
-			else if (PageSwapCache(pgdat->node_mem_map+i))
+			else if (PageSwapCache(page))
 				cached++;
-			else if (page_count(pgdat->node_mem_map+i))
-				shared += page_count(pgdat->node_mem_map+i)-1;
+			else if (page_count(page))
+				shared += page_count(page)-1;
 		}
 		total_present += present;
 		total_reserved += reserved;