Line data    Source code

       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             : 
      13          10 : struct pglist_data *first_online_pgdat(void)
      14             : {
      15          10 :         return NODE_DATA(first_online_node);
      16             : }
      17             : 
      18           5 : struct pglist_data *next_online_pgdat(struct pglist_data *pgdat)
      19             : {
      20           5 :         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             :  */
      30          10 : struct zone *next_zone(struct zone *zone)
      31             : {
      32          10 :         pg_data_t *pgdat = zone->zone_pgdat;
      33             : 
      34          10 :         if (zone < pgdat->node_zones + MAX_NR_ZONES - 1)
      35           5 :                 zone++;
      36             :         else {
      37             :                 pgdat = next_online_pgdat(pgdat);
      38             :                 if (pgdat)
      39             :                         zone = pgdat->node_zones;
      40             :                 else
      41             :                         zone = NULL;
      42             :         }
      43          10 :         return zone;
      44             : }
      45             : 
      46             : static 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 */
      56           0 : struct 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           0 :         if (unlikely(nodes == NULL))
      65           0 :                 while (zonelist_zone_idx(z) > highest_zoneidx)
      66           0 :                         z++;
      67             :         else
      68           0 :                 while (zonelist_zone_idx(z) > highest_zoneidx ||
      69             :                                 (z->zone && !zref_in_nodemask(z, nodes)))
      70           0 :                         z++;
      71             : 
      72           0 :         return z;
      73             : }
      74             : 
      75           1 : void lruvec_init(struct lruvec *lruvec)
      76             : {
      77             :         enum lru_list lru;
      78             : 
      79           1 :         memset(lruvec, 0, sizeof(struct lruvec));
      80           1 :         spin_lock_init(&lruvec->lru_lock);
      81             : 
      82           6 :         for_each_lru(lru)
      83          10 :                 INIT_LIST_HEAD(&lruvec->lists[lru]);
      84             :         /*
      85             :          * The "Unevictable LRU" is imaginary: though its size is maintained,
      86             :          * it is never scanned, and unevictable pages are not threaded on it
      87             :          * (so that their lru fields can be reused to hold mlock_count).
      88             :          * Poison its list head, so that any operations on it would crash.
      89             :          */
      90           2 :         list_del(&lruvec->lists[LRU_UNEVICTABLE]);
      91             : 
      92           1 :         lru_gen_init_lruvec(lruvec);
      93           1 : }
      94             : 
      95             : #if defined(CONFIG_NUMA_BALANCING) && !defined(LAST_CPUPID_NOT_IN_PAGE_FLAGS)
      96             : int page_cpupid_xchg_last(struct page *page, int cpupid)
      97             : {
      98             :         unsigned long old_flags, flags;
      99             :         int last_cpupid;
     100             : 
     101             :         old_flags = READ_ONCE(page->flags);
     102             :         do {
     103             :                 flags = old_flags;
     104             :                 last_cpupid = (flags >> LAST_CPUPID_PGSHIFT) & LAST_CPUPID_MASK;
     105             : 
     106             :                 flags &= ~(LAST_CPUPID_MASK << LAST_CPUPID_PGSHIFT);
     107             :                 flags |= (cpupid & LAST_CPUPID_MASK) << LAST_CPUPID_PGSHIFT;
     108             :         } while (unlikely(!try_cmpxchg(&page->flags, &old_flags, flags)));
     109             : 
     110             :         return last_cpupid;
     111             : }
     112             : #endif