mm/mmzone.c

Source file repositories/reference/linux-study-clean/mm/mmzone.c

File Facts

System
Linux kernel
Corpus path
mm/mmzone.c
Extension
.c
Size
2658 bytes
Lines
114
Domain
Core OS
Bucket
Memory Management
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

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


#include <linux/stddef.h>
#include <linux/mm.h>
#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;
}

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

	return z;
}

void lruvec_init(struct lruvec *lruvec)
{
	enum lru_list lru;

	memset(lruvec, 0, sizeof(struct lruvec));
	spin_lock_init(&lruvec->lru_lock);
	zswap_lruvec_state_init(lruvec);

	for_each_lru(lru)
		INIT_LIST_HEAD(&lruvec->lists[lru]);
	/*
	 * The "Unevictable LRU" is imaginary: though its size is maintained,
	 * it is never scanned, and unevictable pages are not threaded on it
	 * (so that their lru fields can be reused to hold mlock_count).
	 * Poison its list head, so that any operations on it would crash.
	 */

Annotation

Implementation Notes