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