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, 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 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 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 75 void 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 * 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 list_del(&lruvec->lists[LRU_UNEVICTABLE]); 91 92 lru_gen_init_lruvec(lruvec); 93 } 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 113