#endif
enum zone_type {
+#ifdef CONFIG_ZONE_DMA
/*
* ZONE_DMA is used when there are devices that are not able
* to do DMA to all of addressable memory (ZONE_NORMAL). Then we
* <16M.
*/
ZONE_DMA,
+#endif
#ifdef CONFIG_ZONE_DMA32
/*
* x86_64 needs two ZONE_DMAs because it supports devices that are
* match the requested limits. See gfp_zone() in include/linux/gfp.h
*/
-#if !defined(CONFIG_ZONE_DMA32) && !defined(CONFIG_HIGHMEM)
+/*
+ * Count the active zones. Note that the use of defined(X) outside
+ * #if and family is not necessarily defined so ensure we cannot use
+ * it later. Use __ZONE_COUNT to work out how many shift bits we need.
+ */
+#define __ZONE_COUNT ( \
+ defined(CONFIG_ZONE_DMA) \
+ + defined(CONFIG_ZONE_DMA32) \
+ + 1 \
+ + defined(CONFIG_HIGHMEM) \
+)
+#if __ZONE_COUNT < 2
+#define ZONES_SHIFT 0
+#elif __ZONE_COUNT <= 2
#define ZONES_SHIFT 1
-#else
+#elif __ZONE_COUNT <= 4
#define ZONES_SHIFT 2
+#else
+#error ZONES_SHIFT -- too many zones configured adjust calculation
#endif
+#undef __ZONE_COUNT
struct zone {
/* Fields commonly accessed by the page allocator */
static inline int is_dma(struct zone *zone)
{
+#ifdef CONFIG_ZONE_DMA
return zone == zone->zone_pgdat->node_zones + ZONE_DMA;
+#else
+ return 0;
+#endif
}
/* These two functions are used to setup the per zone pages min values */