1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * linux/mm/mmzone.c
4 *
5 * management codes for pgdats, zones and page flags
6 */
7
8
9 #include <linux/stddef.h>
10 #include <linux/mm.h>
11 #include <linux/mmzone.h>
12
13 struct pglist_data *first_online_pgdat(void)
14 {
15 return NODE_DATA(first_online_node);
16 }
17
18 struct 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 */
30 struct 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
46 static 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 */
56 struct zoneref *__next_zones_zonelist(struct zoneref *z,
57 enum zone_type highest_zoneidx,
58 nodemask_t *nodes)
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 (unlikely(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 return z;
73 }
74
75 void lruvec_init(struct lruvec *lruvec)
76 {
77 enum lru_list lru;
78
79 memset(lruvec, 0, sizeof(struct lruvec));
80 spin_lock_init(&lruvec->lru_lock);
81 zswap_lruvec_state_init(lruvec);
82
83 for_each_lru(lru)
84 INIT_LIST_HEAD(&lruvec->lists[lru]);
85 /*
86 * The "Unevictable LRU" is imaginary: though its size is maintained,
87 * it is never scanned, and unevictable pages are not threaded on it
88 * (so that their lru fields can be reused to hold mlock_count).
89 * Poison its list head, so that any operations on it would crash.
90 */
91 list_del(&lruvec->lists[LRU_UNEVICTABLE]);
92
93 lru_gen_init_lruvec(lruvec);
94 }
95
96 #if defined(CONFIG_NUMA_BALANCING) && !defined(LAST_CPUPID_NOT_IN_PAGE_FLAGS)
97 int folio_xchg_last_cpupid(struct folio *folio, int cpupid)
98 {
99 unsigned long old_flags, flags;
100 int last_cpupid;
101
102 old_flags = READ_ONCE(folio->flags);
103 do {
104 flags = old_flags;
105 last_cpupid = (flags >> LAST_CPUPID_PGSHIFT) & LAST_CPUPID_MASK;
106
107 flags &= ~(LAST_CPUPID_MASK << LAST_CPUPID_PGSHIFT);
108 flags |= (cpupid & LAST_CPUPID_MASK) << LAST_CPUPID_PGSHIFT;
109 } while (unlikely(!try_cmpxchg(&folio->flags, &old_flags, flags)));
110
111 return last_cpupid;
112 }
113 #endif
114
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