LXR linux/mm/mmzone.c

   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
  75void lruvec_init(struct lruvec *lruvec)
  76{
  77        enum lru_list lru;
  78
  79        memset(lruvec, 0, sizeof(struct lruvec));
  80        spin_lock_init(&lruvec->lru_lock);
  81
  82        for_each_lru(lru)
  83                INIT_LIST_HEAD(&lruvec->lists[lru]);
  84}
  85
  86#if defined(CONFIG_NUMA_BALANCING) && !defined(LAST_CPUPID_NOT_IN_PAGE_FLAGS)
  87int page_cpupid_xchg_last(struct page *page, int cpupid)
  88{
  89        unsigned long old_flags, flags;
  90        int last_cpupid;
  91
  92        do {
  93                old_flags = flags = page->flags;
  94                last_cpupid = page_cpupid_last(page);
  95
  96                flags &= ~(LAST_CPUPID_MASK << LAST_CPUPID_PGSHIFT);
  97                flags |= (cpupid & LAST_CPUPID_MASK) << LAST_CPUPID_PGSHIFT;
  98        } while (unlikely(cmpxchg(&page->flags, old_flags, flags) != old_flags));
  99
 100        return last_cpupid;
 101}
 102#endif
 103