mmzone.c 2.4 KB
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// SPDX-License-Identifier: GPL-2.0
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/*
 * linux/mm/mmzone.c
 *
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 * management codes for pgdats, zones and page flags
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 */


#include <linux/stddef.h>
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#include <linux/mm.h>
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#include <linux/mmzone.h>

struct pglist_data *first_online_pgdat(void)
{
	return NODE_DATA(first_online_node);
}

struct pglist_data *next_online_pgdat(struct pglist_data *pgdat)
{
	int nid = next_online_node(pgdat->node_id);

	if (nid == MAX_NUMNODES)
		return NULL;
	return NODE_DATA(nid);
}

/*
 * next_zone - helper magic for for_each_zone()
 */
struct zone *next_zone(struct zone *zone)
{
	pg_data_t *pgdat = zone->zone_pgdat;

	if (zone < pgdat->node_zones + MAX_NR_ZONES - 1)
		zone++;
	else {
		pgdat = next_online_pgdat(pgdat);
		if (pgdat)
			zone = pgdat->node_zones;
		else
			zone = NULL;
	}
	return zone;
}

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static inline int zref_in_nodemask(struct zoneref *zref, nodemask_t *nodes)
{
#ifdef CONFIG_NUMA
	return node_isset(zonelist_node_idx(zref), *nodes);
#else
	return 1;
#endif /* CONFIG_NUMA */
}

/* Returns the next zone at or below highest_zoneidx in a zonelist */
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struct zoneref *__next_zones_zonelist(struct zoneref *z,
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					enum zone_type highest_zoneidx,
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					nodemask_t *nodes)
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{
	/*
	 * Find the next suitable zone to use for the allocation.
	 * Only filter based on nodemask if it's set
	 */
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	if (unlikely(nodes == NULL))
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		while (zonelist_zone_idx(z) > highest_zoneidx)
			z++;
	else
		while (zonelist_zone_idx(z) > highest_zoneidx ||
				(z->zone && !zref_in_nodemask(z, nodes)))
			z++;

	return z;
}
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#ifdef CONFIG_ARCH_HAS_HOLES_MEMORYMODEL
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bool memmap_valid_within(unsigned long pfn,
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					struct page *page, struct zone *zone)
{
	if (page_to_pfn(page) != pfn)
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		return false;
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	if (page_zone(page) != zone)
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		return false;
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	return true;
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}
#endif /* CONFIG_ARCH_HAS_HOLES_MEMORYMODEL */
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void lruvec_init(struct lruvec *lruvec)
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{
	enum lru_list lru;

	memset(lruvec, 0, sizeof(struct lruvec));

	for_each_lru(lru)
		INIT_LIST_HEAD(&lruvec->lists[lru]);
}
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#if defined(CONFIG_NUMA_BALANCING) && !defined(LAST_CPUPID_NOT_IN_PAGE_FLAGS)
int page_cpupid_xchg_last(struct page *page, int cpupid)
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{
	unsigned long old_flags, flags;
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	int last_cpupid;
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	do {
		old_flags = flags = page->flags;
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		last_cpupid = page_cpupid_last(page);
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		flags &= ~(LAST_CPUPID_MASK << LAST_CPUPID_PGSHIFT);
		flags |= (cpupid & LAST_CPUPID_MASK) << LAST_CPUPID_PGSHIFT;
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	} while (unlikely(cmpxchg(&page->flags, old_flags, flags) != old_flags));

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	return last_cpupid;
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}
#endif