[PATCH] x86: don't reallocate pgt for node0

[Yinghai Lu <yhlu.kernel@gmail.com>]

kva ram already mapped right after away, so don't need to get that for low ram.
avoid wasting one copy pgdat.

also add node id in early_res name in case get it from find_e820_area.

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>

---
 arch/x86/mm/discontig_32.c |   11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

Index: linux-2.6/arch/x86/mm/discontig_32.c
===================================================================
--- linux-2.6.orig/arch/x86/mm/discontig_32.c
+++ linux-2.6/arch/x86/mm/discontig_32.c
@@ -156,17 +156,20 @@ static void __init propagate_e820_map_no
  */
 static void __init allocate_pgdat(int nid)
 {
-	if (nid && node_has_online_mem(nid) && node_remap_start_vaddr[nid])
+	char buf[16];
+
+	if (node_has_online_mem(nid) && node_remap_start_vaddr[nid])
 		NODE_DATA(nid) = (pg_data_t *)node_remap_start_vaddr[nid];
 	else {
 		unsigned long pgdat_phys;
 		pgdat_phys = find_e820_area(min_low_pfn<<PAGE_SHIFT,
-				 (nid ? max_low_pfn:max_pfn_mapped)<<PAGE_SHIFT,
+				 max_pfn_mapped<<PAGE_SHIFT,
 				 sizeof(pg_data_t),
 				 PAGE_SIZE);
 		NODE_DATA(nid) = (pg_data_t *)(pfn_to_kaddr(pgdat_phys>>PAGE_SHIFT));
-		reserve_early(pgdat_phys, pgdat_phys + sizeof(pg_data_t),
-			      "NODE_DATA");
+		memset(buf, 0, sizeof(buf));
+		sprintf(buf, "NODE_DATA %d",  nid);
+		reserve_early(pgdat_phys, pgdat_phys + sizeof(pg_data_t), buf);
 	}
 	printk(KERN_DEBUG "allocate_pgdat: node %d NODE_DATA %08lx\n",
 		nid, (unsigned long)NODE_DATA(nid));