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/mm.h> 10 #include <linux/mmzone.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 45 static inline int zref_in_nodemask(struct zoneref *zref, nodemask_t *nodes) 46 { 47 #ifdef CONFIG_NUMA 48 return node_isset(zonelist_node_idx(zref), *nodes); 49 #else 50 return 1; 51 #endif /* CONFIG_NUMA */ 52 } 53 54 /* Returns the next zone at or below highest_zoneidx in a zonelist */ 55 struct zoneref *next_zones_zonelist(struct zoneref *z, 56 enum zone_type highest_zoneidx, 57 nodemask_t *nodes, 58 struct zone **zone) 59 { 60 /* 61 * Find the next suitable zone to use for the allocation. 62 * Only filter based on nodemask if it's set 63 */ 64 if (likely(nodes == NULL)) 65 while (zonelist_zone_idx(z) > highest_zoneidx) 66 z++; 67 else 68 while (zonelist_zone_idx(z) > highest_zoneidx || 69 (z->zone && !zref_in_nodemask(z, nodes))) 70 z++; 71 72 *zone = zonelist_zone(z); 73 return z; 74 } 75 76 #ifdef CONFIG_ARCH_HAS_HOLES_MEMORYMODEL 77 int memmap_valid_within(unsigned long pfn, 78 struct page *page, struct zone *zone) 79 { 80 if (page_to_pfn(page) != pfn) 81 return 0; 82 83 if (page_zone(page) != zone) 84 return 0; 85 86 return 1; 87 } 88 #endif /* CONFIG_ARCH_HAS_HOLES_MEMORYMODEL */ 89