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
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{
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
75int memmap_valid_within(unsigned long pfn,
76					struct page *page, struct zone *zone)
77{
78	if (page_to_pfn(page) != pfn)
79		return 0;
80
81	if (page_zone(page) != zone)
82		return 0;
83
84	return 1;
85}
86#endif /* CONFIG_ARCH_HAS_HOLES_MEMORYMODEL */
87
88void 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)
99int 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
115