x86: make sparse mem work in non-NUMA mode

With sparse memory, holes should not be marked present for memmap.
This patch makes sure sparsemem really works on SMP mode (!NUMA).

[ Impact: use less memory to map fragmented RAM, avoid boot-OOM/crash ]
Signed-off-by: NShaohua Li <shaohua.li@intel.com>
Signed-off-by: NSheng Yang <sheng.yang@intel.com>
LKML-Reference: <1242117600.22431.0.camel@sli10-desk.sh.intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/mm/init_32.c

@@ -706,15 +706,15 @@ void __init initmem_init(unsigned long start_pfn,
 	highstart_pfn = highend_pfn = max_pfn;
 	if (max_pfn > max_low_pfn)
 		highstart_pfn = max_low_pfn;
-	memory_present(0, 0, highend_pfn);
 	e820_register_active_regions(0, 0, highend_pfn);
+	sparse_memory_present_with_active_regions(0);
 	printk(KERN_NOTICE "%ldMB HIGHMEM available.\n",
 		pages_to_mb(highend_pfn - highstart_pfn));
 	num_physpages = highend_pfn;
 	high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
 #else
-	memory_present(0, 0, max_low_pfn);
 	e820_register_active_regions(0, 0, max_low_pfn);
+	sparse_memory_present_with_active_regions(0);
 	num_physpages = max_low_pfn;
 	high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
 #endif