mm/mmzone.c

   1 /*
   2  * linux/mm/mmzone.c
   3  *
   4  * management codes for pgdats, zones and page flags
   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 {
  59         /*
  60          * Find the next suitable zone to use for the allocation.
  61          * Only filter based on nodemask if it's set
  62          */
  63         if (likely(nodes == NULL))
  64                 while (zonelist_zone_idx(z) > highest_zoneidx)
  65                         z++;
  66         else
  67                 while (zonelist_zone_idx(z) > highest_zoneidx ||
  68                                 (z->zone && !zref_in_nodemask(z, nodes)))
  69                         z++;
  70
  71         return z;
  72 }
  73
  74 #ifdef CONFIG_ARCH_HAS_HOLES_MEMORYMODEL
  75 bool memmap_valid_within(unsigned long pfn,
  76                                         struct page *page, struct zone *zone)
  77 {
  78         if (page_to_pfn(page) != pfn)
  79                 return false;
  80
  81         if (page_zone(page) != zone)
  82                 return false;
  83
  84         return true;
  85 }
  86 #endif /* CONFIG_ARCH_HAS_HOLES_MEMORYMODEL */
  87
  88 void lruvec_init(struct lruvec *lruvec)
  89 {
  90         enum lru_list lru;
  91
  92         memset(lruvec, 0, sizeof(struct lruvec));
  93
  94         for_each_lru(lru)
  95                 INIT_LIST_HEAD(&lruvec->lists[lru]);
  96 }
  97
  98 #if defined(CONFIG_NUMA_BALANCING) && !defined(LAST_CPUPID_NOT_IN_PAGE_FLAGS)
  99 int page_cpupid_xchg_last(struct page *page, int cpupid)
 100 {
 101         unsigned long old_flags, flags;
 102         int last_cpupid;
 103
 104         do {
 105                 old_flags = flags = page->flags;
 106                 last_cpupid = page_cpupid_last(page);
 107
 108                 flags &= ~(LAST_CPUPID_MASK << LAST_CPUPID_PGSHIFT);
 109                 flags |= (cpupid & LAST_CPUPID_MASK) << LAST_CPUPID_PGSHIFT;
 110         } while (unlikely(cmpxchg(&page->flags, old_flags, flags) != old_flags));
 111
 112         return last_cpupid;
 113 }
 114 #endif