[PATCH] define for_each_online_pgdat

This patch defines for_each_online_pgdat() as a replacement of
for_each_pgdat()

Now, online nodes are managed by node_online_map.  But for_each_pgdat()
uses pgdat_link to iterate over all nodes(pgdat).  This means management
structure for online pgdat is duplicated.

I think using node_online_map for for_each_pgdat() is simple and sane
rather ather than pgdat_link.  New macro is named as
for_each_online_pgdat().  Following patch will fix callers of
for_each_pgdat().

The bootmem allocater uses for_each_pgdat() before pgdat initialization.  I
don't think it's sane.  Following patch will fix it.

Signed-off-by: Yasunori Goto     <y-goto@jp.fujitsu.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index ace31c5..96eb080 100644 (file)
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -13,6 +13,7 @@
 #include <linux/numa.h>
 #include <linux/init.h>
 #include <linux/seqlock.h>
+#include <linux/nodemask.h>
 #include <asm/atomic.h>
 
 /* Free memory management - zoned buddy allocator.  */
@@ -349,57 +350,6 @@ unsigned long __init node_memmap_size_bytes(int, unsigned long, unsigned long);
  */
 #define zone_idx(zone)         ((zone) - (zone)->zone_pgdat->node_zones)
 
-/**
- * for_each_pgdat - helper macro to iterate over all nodes
- * @pgdat - pointer to a pg_data_t variable
- *
- * Meant to help with common loops of the form
- * pgdat = pgdat_list;
- * while(pgdat) {
- *     ...
- *     pgdat = pgdat->pgdat_next;
- * }
- */
-#define for_each_pgdat(pgdat) \
-       for (pgdat = pgdat_list; pgdat; pgdat = pgdat->pgdat_next)
-
-/*
- * next_zone - helper magic for for_each_zone()
- * Thanks to William Lee Irwin III for this piece of ingenuity.
- */
-static inline struct zone *next_zone(struct zone *zone)
-{
-       pg_data_t *pgdat = zone->zone_pgdat;
-
-       if (zone < pgdat->node_zones + MAX_NR_ZONES - 1)
-               zone++;
-       else if (pgdat->pgdat_next) {
-               pgdat = pgdat->pgdat_next;
-               zone = pgdat->node_zones;
-       } else
-               zone = NULL;
-
-       return zone;
-}
-
-/**
- * for_each_zone - helper macro to iterate over all memory zones
- * @zone - pointer to struct zone variable
- *
- * The user only needs to declare the zone variable, for_each_zone
- * fills it in. This basically means for_each_zone() is an
- * easier to read version of this piece of code:
- *
- * for (pgdat = pgdat_list; pgdat; pgdat = pgdat->node_next)
- *     for (i = 0; i < MAX_NR_ZONES; ++i) {
- *             struct zone * z = pgdat->node_zones + i;
- *             ...
- *     }
- * }
- */
-#define for_each_zone(zone) \
-       for (zone = pgdat_list->node_zones; zone; zone = next_zone(zone))
-
 static inline int populated_zone(struct zone *zone)
 {
        return (!!zone->present_pages);
@@ -471,6 +421,62 @@ extern struct pglist_data contig_page_data;
 
 #endif /* !CONFIG_NEED_MULTIPLE_NODES */
 
+static inline struct pglist_data *first_online_pgdat(void)
+{
+       return NODE_DATA(first_online_node);
+}
+
+static inline struct pglist_data *next_online_pgdat(struct pglist_data *pgdat)
+{
+       int nid = next_online_node(pgdat->node_id);
+
+       if (nid == MAX_NUMNODES)
+               return NULL;
+       return NODE_DATA(nid);
+}
+
+
+/**
+ * for_each_pgdat - helper macro to iterate over all nodes
+ * @pgdat - pointer to a pg_data_t variable
+ */
+#define for_each_online_pgdat(pgdat)                   \
+       for (pgdat = first_online_pgdat();              \
+            pgdat;                                     \
+            pgdat = next_online_pgdat(pgdat))
+
+/*
+ * next_zone - helper magic for for_each_zone()
+ * Thanks to William Lee Irwin III for this piece of ingenuity.
+ */
+static inline struct zone *next_zone(struct zone *zone)
+{
+       pg_data_t *pgdat = zone->zone_pgdat;
+
+       if (zone < pgdat->node_zones + MAX_NR_ZONES - 1)
+               zone++;
+       else {
+               pgdat = next_online_pgdat(pgdat);
+               if (pgdat)
+                       zone = pgdat->node_zones;
+               else
+                       zone = NULL;
+       }
+       return zone;
+}
+
+/**
+ * for_each_zone - helper macro to iterate over all memory zones
+ * @zone - pointer to struct zone variable
+ *
+ * The user only needs to declare the zone variable, for_each_zone
+ * fills it in.
+ */
+#define for_each_zone(zone)                            \
+       for (zone = (first_online_pgdat())->node_zones; \
+            zone;                                      \
+            zone = next_zone(zone))
+
 #ifdef CONFIG_SPARSEMEM
 #include <asm/sparsemem.h>
 #endif

diff --git a/include/linux/nodemask.h b/include/linux/nodemask.h
index b959a45..1a9ef3e 100644 (file)
--- a/include/linux/nodemask.h
+++ b/include/linux/nodemask.h
@@ -350,11 +350,15 @@ extern nodemask_t node_possible_map;
 #define num_possible_nodes()   nodes_weight(node_possible_map)
 #define node_online(node)      node_isset((node), node_online_map)
 #define node_possible(node)    node_isset((node), node_possible_map)
+#define first_online_node      first_node(node_online_map)
+#define next_online_node(nid)  next_node((nid), node_online_map)
 #else
 #define num_online_nodes()     1
 #define num_possible_nodes()   1
 #define node_online(node)      ((node) == 0)
 #define node_possible(node)    ((node) == 0)
+#define first_online_node      0
+#define next_online_node(nid)  (MAX_NUMNODES)
 #endif
 
 #define any_online_node(mask)                  \