x86/mm/numa: Fix 32-bit kernel NUMA boot

When booting a 32-bit x86 kernel on a NUMA machine, node data
cannot be allocated from local node if the account of memory for
node 0 covers the low memory space entirely:

  [    0.000000] Initmem setup node 0 [mem 0x00000000-0x83fffffff]
  [    0.000000]   NODE_DATA [mem 0x367ed000-0x367edfff]
  [    0.000000] Initmem setup node 1 [mem 0x840000000-0xfffffffff]
  [    0.000000] Cannot find 4096 bytes in node 1
  [    0.000000] 64664MB HIGHMEM available.
  [    0.000000] 871MB LOWMEM available.

To fix this issue, node data is allowed to be allocated from
other nodes if the memory of local node is still not mapped. The
expected result looks like this:

  [    0.000000] Initmem setup node 0 [mem 0x00000000-0x83fffffff]
  [    0.000000]   NODE_DATA [mem 0x367ed000-0x367edfff]
  [    0.000000] Initmem setup node 1 [mem 0x840000000-0xfffffffff]
  [    0.000000]   NODE_DATA [mem 0x367ec000-0x367ecfff]
  [    0.000000]     NODE_DATA(1) on node 0
  [    0.000000] 64664MB HIGHMEM available.
  [    0.000000] 871MB LOWMEM available.
Signed-off-by: Lans Zhang <jia.zhang@windriver.com>
Cc: <andi@firstfloor.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1386303510-18574-1-git-send-email-jia.zhang@windriver.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/mm/numa.c

@@ -210,11 +210,15 @@ static void __init setup_node_data(int nid, u64 start, u64 end)
 	 * Never allocate in DMA zone.
 	 */
 	nd_pa = memblock_alloc_nid(nd_size, SMP_CACHE_BYTES, nid);
+	if (!nd_pa) {
+		nd_pa = __memblock_alloc_base(nd_size, SMP_CACHE_BYTES,
+					      MEMBLOCK_ALLOC_ACCESSIBLE);
 		if (!nd_pa) {
 			pr_err("Cannot find %zu bytes in node %d\n",
 			       nd_size, nid);
 			return;
 		}
+	}
 	nd = __va(nd_pa);
 
 	/* report and initialize */