mm/mmzone.c

   1 /*
   2  * linux/mm/mmzone.c
   3  *
   4  * management codes for pgdats and zones.
   5  */
   6
   7
   8 #include <linux/stddef.h>
   9 #include <linux/mmzone.h>
  10 #include <linux/module.h>
  11
  12 struct pglist_data *first_online_pgdat(void)
  13 {
  14         return NODE_DATA(first_online_node);
  15 }
  16
  17 struct pglist_data *next_online_pgdat(struct pglist_data *pgdat)
  18 {
  19         int nid = next_online_node(pgdat->node_id);
  20
  21         if (nid == MAX_NUMNODES)
  22                 return NULL;
  23         return NODE_DATA(nid);
  24 }
  25
  26 /*
  27  * next_zone - helper magic for for_each_zone()
  28  */
  29 struct zone *next_zone(struct zone *zone)
  30 {
  31         pg_data_t *pgdat = zone->zone_pgdat;
  32
  33         if (zone < pgdat->node_zones + MAX_NR_ZONES - 1)
  34                 zone++;
  35         else {
  36                 pgdat = next_online_pgdat(pgdat);
  37                 if (pgdat)
  38                         zone = pgdat->node_zones;
  39                 else
  40                         zone = NULL;
  41         }
  42         return zone;
  43 }
  44