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95144c78
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1/*
2 * linux/mm/mmzone.c
3 *
4 * management codes for pgdats and zones.
5 */
6
7
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8#include <linux/stddef.h>
9#include <linux/mmzone.h>
10#include <linux/module.h>
11
12struct pglist_data *first_online_pgdat(void)
13{
14 return NODE_DATA(first_online_node);
15}
16
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17struct 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}
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25
26/*
27 * next_zone - helper magic for for_each_zone()
28 */
29struct 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}
95144c78 44
19770b32
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45static 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 */
55struct 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}