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
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{
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#ifdef CONFIG_ARCH_HAS_HOLES_MEMORYMODEL
76bool memmap_valid_within(unsigned long pfn,
77 struct page *page, struct zone *zone)
78{
79 if (page_to_pfn(page) != pfn)
80 return false;
81
82 if (page_zone(page) != zone)
83 return false;
84
85 return true;
86}
87#endif /* CONFIG_ARCH_HAS_HOLES_MEMORYMODEL */
88
89void lruvec_init(struct lruvec *lruvec)
90{
91 enum lru_list lru;
92
93 memset(lruvec, 0, sizeof(struct lruvec));
94
95 for_each_lru(lru)
96 INIT_LIST_HEAD(&lruvec->lists[lru]);
97}
98
99#if defined(CONFIG_NUMA_BALANCING) && !defined(LAST_CPUPID_NOT_IN_PAGE_FLAGS)
100int page_cpupid_xchg_last(struct page *page, int cpupid)
101{
102 unsigned long old_flags, flags;
103 int last_cpupid;
104
105 do {
106 old_flags = flags = page->flags;
107 last_cpupid = page_cpupid_last(page);
108
109 flags &= ~(LAST_CPUPID_MASK << LAST_CPUPID_PGSHIFT);
110 flags |= (cpupid & LAST_CPUPID_MASK) << LAST_CPUPID_PGSHIFT;
111 } while (unlikely(cmpxchg(&page->flags, old_flags, flags) != old_flags));
112
113 return last_cpupid;
114}
115#endif
116