mm: suppress pfn range output for zones without pages

free_area_init_nodes() emits pfn ranges for all zones on the system. There may be no pages on a higher zone, however, due to memory limitations or the use of the mem= kernel parameter. For example: Zone PFN ranges: DMA 0x00000001 -> 0x00001000 DMA32 0x00001000 -> 0x00100000 Normal 0x00100000 -> 0x00100000 The implementation copies the previous zone's highest pfn, if any, as the next zone's lowest pfn. If its highest pfn is then greater than the amount of addressable memory, the upper memory limit is used instead. Thus, both the lowest and highest possible pfn for higher zones without memory may be the same. The pfn range for zones without memory is now shown as "empty" instead. Signed-off-by: David Rientjes <[email protected]> Cc: Mel Gorman <[email protected]> Reviewed-by: Christoph Lameter <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
chewitt · Mar 6, 2010 · 72f0ba0 · 72f0ba0
1 parent 452aa69
commit 72f0ba0
Showing 1 changed file with 6 additions and 2 deletions.
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
@@ -4392,8 +4392,12 @@ void __init free_area_init_nodes(unsigned long *max_zone_pfn)
 	for (i = 0; i < MAX_NR_ZONES; i++) {
 		if (i == ZONE_MOVABLE)
 			continue;
-		printk("  %-8s %0#10lx -> %0#10lx\n",
-				zone_names[i],
+		printk("  %-8s ", zone_names[i]);
+		if (arch_zone_lowest_possible_pfn[i] ==
+				arch_zone_highest_possible_pfn[i])
+			printk("empty\n");
+		else
+			printk("%0#10lx -> %0#10lx\n",
 				arch_zone_lowest_possible_pfn[i],
 				arch_zone_highest_possible_pfn[i]);
 	}