Root/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/mm.h>
10#include <linux/mmzone.h>
11
12struct pglist_data *first_online_pgdat(void)
13{
14    return NODE_DATA(first_online_node);
15}
16
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}
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}
44
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}
75
76#ifdef CONFIG_ARCH_HAS_HOLES_MEMORYMODEL
77int 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
90void lruvec_init(struct lruvec *lruvec, struct zone *zone)
91{
92    enum lru_list lru;
93
94    memset(lruvec, 0, sizeof(struct lruvec));
95
96    for_each_lru(lru)
97        INIT_LIST_HEAD(&lruvec->lists[lru]);
98
99#ifdef CONFIG_MEMCG
100    lruvec->zone = zone;
101#endif
102}
103

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