Merge to Fedora kernel-2.6.7-1.492

[linux-2.6.git] / include / linux / mmzone.h

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index f1e1a72..2560131 100644 (file)
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -20,6 +20,14 @@
 #define MAX_ORDER CONFIG_FORCE_MAX_ZONEORDER
 #endif
 
+/*
+ * system hash table size limits
+ * - on large memory machines, we may want to allocate a bigger hash than that
+ *   permitted by MAX_ORDER, so we allocate with the bootmem allocator, and are
+ *   limited to this size
+ */
+#define MAX_SYS_HASH_TABLE_ORDER 7
+
 struct free_area {
        struct list_head        free_list;
        unsigned long           *map;
@@ -69,7 +77,34 @@ struct per_cpu_pageset {
 #define MAX_NR_ZONES           3       /* Sync this with ZONES_SHIFT */
 #define ZONES_SHIFT            2       /* ceil(log2(MAX_NR_ZONES)) */
 
+
+/*
+ * When a memory allocation must conform to specific limitations (such
+ * as being suitable for DMA) the caller will pass in hints to the
+ * allocator in the gfp_mask, in the zone modifier bits.  These bits
+ * are used to select a priority ordered list of memory zones which
+ * match the requested limits.  GFP_ZONEMASK defines which bits within
+ * the gfp_mask should be considered as zone modifiers.  Each valid
+ * combination of the zone modifier bits has a corresponding list
+ * of zones (in node_zonelists).  Thus for two zone modifiers there
+ * will be a maximum of 4 (2 ** 2) zonelists, for 3 modifiers there will
+ * be 8 (2 ** 3) zonelists.  GFP_ZONETYPES defines the number of possible
+ * combinations of zone modifiers in "zone modifier space".
+ */
 #define GFP_ZONEMASK   0x03
+/*
+ * As an optimisation any zone modifier bits which are only valid when
+ * no other zone modifier bits are set (loners) should be placed in
+ * the highest order bits of this field.  This allows us to reduce the
+ * extent of the zonelists thus saving space.  For example in the case
+ * of three zone modifier bits, we could require up to eight zonelists.
+ * If the left most zone modifier is a "loner" then the highest valid
+ * zonelist would be four allowing us to allocate only five zonelists.
+ * Use the first form when the left most bit is not a "loner", otherwise
+ * use the second.
+ */
+/* #define GFP_ZONETYPES       (GFP_ZONEMASK + 1) */           /* Non-loner */
+#define GFP_ZONETYPES  ((GFP_ZONEMASK + 1) / 2 + 1)            /* Loner */
 
 /*
  * On machines where it is needed (eg PCs) we divide physical memory
@@ -106,8 +141,8 @@ struct zone {
        spinlock_t              lru_lock;       
        struct list_head        active_list;
        struct list_head        inactive_list;
-       atomic_t                nr_scan_active;
-       atomic_t                nr_scan_inactive;
+       unsigned long           nr_scan_active;
+       unsigned long           nr_scan_inactive;
        unsigned long           nr_active;
        unsigned long           nr_inactive;
        int                     all_unreclaimable; /* All pages pinned */
@@ -225,7 +260,7 @@ struct zonelist {
 struct bootmem_data;
 typedef struct pglist_data {
        struct zone node_zones[MAX_NR_ZONES];
-       struct zonelist node_zonelists[MAX_NR_ZONES];
+       struct zonelist node_zonelists[GFP_ZONETYPES];
        int nr_zones;
        struct page *node_mem_map;
        struct bootmem_data *bdata;