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#include <linux/module.h> 12 13struct pglist_data *first_online_pgdat(void) 14{ 15 return NODE_DATA(first_online_node); 16} 17 18struct pglist_data *next_online_pgdat(struct pglist_data *pgdat) 19{ 20 int nid = next_online_node(pgdat->node_id); 21 22 if (nid == MAX_NUMNODES) 23 return NULL; 24 return NODE_DATA(nid); 25} 26 27/* 28 * next_zone - helper magic for for_each_zone() 29 */ 30struct zone *next_zone(struct zone *zone) 31{ 32 pg_data_t *pgdat = zone->zone_pgdat; 33 34 if (zone < pgdat->node_zones + MAX_NR_ZONES - 1) 35 zone++; 36 else { 37 pgdat = next_online_pgdat(pgdat); 38 if (pgdat) 39 zone = pgdat->node_zones; 40 else 41 zone = NULL; 42 } 43 return zone; 44} 45 46static inline int zref_in_nodemask(struct zoneref *zref, nodemask_t *nodes) 47{ 48#ifdef CONFIG_NUMA 49 return node_isset(zonelist_node_idx(zref), *nodes); 50#else 51 return 1; 52#endif /* CONFIG_NUMA */ 53} 54 55/* Returns the next zone at or below highest_zoneidx in a zonelist */ 56struct zoneref *next_zones_zonelist(struct zoneref *z, 57 enum zone_type highest_zoneidx, 58 nodemask_t *nodes, 59 struct zone **zone) 60{ 61 /* 62 * Find the next suitable zone to use for the allocation. 63 * Only filter based on nodemask if it's set 64 */ 65 if (likely(nodes == NULL)) 66 while (zonelist_zone_idx(z) > highest_zoneidx) 67 z++; 68 else 69 while (zonelist_zone_idx(z) > highest_zoneidx || 70 (z->zone && !zref_in_nodemask(z, nodes))) 71 z++; 72 73 *zone = zonelist_zone(z); 74 return z; 75} 76 77#ifdef CONFIG_ARCH_HAS_HOLES_MEMORYMODEL 78int memmap_valid_within(unsigned long pfn, 79 struct page *page, struct zone *zone) 80{ 81 if (page_to_pfn(page) != pfn) 82 return 0; 83 84 if (page_zone(page) != zone) 85 return 0; 86 87 return 1; 88} 89#endif /* CONFIG_ARCH_HAS_HOLES_MEMORYMODEL */ 90