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 struct pglist_data *first_online_pgdat(void) 14 { 15 return NODE_DATA(first_online_node); 16 } 17 18 struct 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 */ 30 struct 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 46 static inline int zref_in_nodemask(struct zoneref *zref, 47 const nodemask_t *nodes) 48 { 49 #ifdef CONFIG_NUMA 50 return node_isset(zonelist_node_idx(zref), *nodes); 51 #else 52 return 1; 53 #endif /* CONFIG_NUMA */ 54 } 55 56 /* Returns the next zone at or below highest_zoneidx in a zonelist */ 57 struct zoneref *__next_zones_zonelist(struct zoneref *z, 58 enum zone_type highest_zoneidx, 59 const nodemask_t *nodes) 60 { 61 /* 62 * Find the next suitable zone to use for the allocation. 63 * Only filter based on nodemask if it's set 64 */ 65 if (unlikely(nodes == NULL)) 66 while (zonelist_zone_idx(z) > highest_zoneidx) 67 z++; 68 else 69 while (zonelist_zone_idx(z) > highest_zoneidx || 70 (zonelist_zone(z) && !zref_in_nodemask(z, nodes))) 71 z++; 72 73 return z; 74 } 75 76 void lruvec_init(struct lruvec *lruvec) 77 { 78 enum lru_list lru; 79 80 memset(lruvec, 0, sizeof(struct lruvec)); 81 spin_lock_init(&lruvec->lru_lock); 82 spin_lock_init(&lruvec->cost_lock); 83 zswap_lruvec_state_init(lruvec); 84 85 for_each_lru(lru) 86 INIT_LIST_HEAD(&lruvec->lists[lru]); 87 /* 88 * The "Unevictable LRU" is imaginary: though its size is maintained, 89 * it is never scanned, and unevictable pages are not threaded on it 90 * (so that their lru fields can be reused to hold mlock_count). 91 * Poison its list head, so that any operations on it would crash. 92 */ 93 list_del(&lruvec->lists[LRU_UNEVICTABLE]); 94 95 lru_gen_init_lruvec(lruvec); 96 } 97 98 #if defined(CONFIG_NUMA_BALANCING) && !defined(LAST_CPUPID_NOT_IN_PAGE_FLAGS) 99 int folio_xchg_last_cpupid(struct folio *folio, int cpupid) 100 { 101 unsigned long old_flags, flags; 102 int last_cpupid; 103 104 old_flags = READ_ONCE(folio->flags.f); 105 do { 106 flags = old_flags; 107 last_cpupid = (flags >> LAST_CPUPID_PGSHIFT) & LAST_CPUPID_MASK; 108 109 flags &= ~(LAST_CPUPID_MASK << LAST_CPUPID_PGSHIFT); 110 flags |= (cpupid & LAST_CPUPID_MASK) << LAST_CPUPID_PGSHIFT; 111 } while (unlikely(!try_cmpxchg(&folio->flags.f, &old_flags, flags))); 112 113 return last_cpupid; 114 } 115 #endif 116