1 #ifndef _LINUX_COMPACTION_H 2 #define _LINUX_COMPACTION_H 3 4 #include <linux/node.h> 5 6 /* Return values for compact_zone() and try_to_compact_pages() */ 7 /* compaction didn't start as it was not possible or direct reclaim was more suitable */ 8 #define COMPACT_SKIPPED 0 9 /* compaction should continue to another pageblock */ 10 #define COMPACT_CONTINUE 1 11 /* direct compaction partially compacted a zone and there are suitable pages */ 12 #define COMPACT_PARTIAL 2 13 /* The full zone was compacted */ 14 #define COMPACT_COMPLETE 3 15 16 /* 17 * compaction supports three modes 18 * 19 * COMPACT_ASYNC_MOVABLE uses asynchronous migration and only scans 20 * MIGRATE_MOVABLE pageblocks as migration sources and targets. 21 * COMPACT_ASYNC_UNMOVABLE uses asynchronous migration and only scans 22 * MIGRATE_MOVABLE pageblocks as migration sources. 23 * MIGRATE_UNMOVABLE pageblocks are scanned as potential migration 24 * targets and convers them to MIGRATE_MOVABLE if possible 25 * COMPACT_SYNC uses synchronous migration and scans all pageblocks 26 */ 27 enum compact_mode { 28 COMPACT_ASYNC_MOVABLE, 29 COMPACT_ASYNC_UNMOVABLE, 30 COMPACT_SYNC, 31 }; 32 33 #ifdef CONFIG_COMPACTION 34 extern int sysctl_compact_memory; 35 extern int sysctl_compaction_handler(struct ctl_table *table, int write, 36 void __user *buffer, size_t *length, loff_t *ppos); 37 extern int sysctl_extfrag_threshold; 38 extern int sysctl_extfrag_handler(struct ctl_table *table, int write, 39 void __user *buffer, size_t *length, loff_t *ppos); 40 41 extern int fragmentation_index(struct zone *zone, unsigned int order); 42 extern unsigned long try_to_compact_pages(struct zonelist *zonelist, 43 int order, gfp_t gfp_mask, nodemask_t *mask, 44 bool sync); 45 extern int compact_pgdat(pg_data_t *pgdat, int order); 46 extern unsigned long compaction_suitable(struct zone *zone, int order); 47 48 /* Do not skip compaction more than 64 times */ 49 #define COMPACT_MAX_DEFER_SHIFT 6 50 51 /* 52 * Compaction is deferred when compaction fails to result in a page 53 * allocation success. 1 << compact_defer_limit compactions are skipped up 54 * to a limit of 1 << COMPACT_MAX_DEFER_SHIFT 55 */ 56 static inline void defer_compaction(struct zone *zone, int order) 57 { 58 zone->compact_considered = 0; 59 zone->compact_defer_shift++; 60 61 if (order < zone->compact_order_failed) 62 zone->compact_order_failed = order; 63 64 if (zone->compact_defer_shift > COMPACT_MAX_DEFER_SHIFT) 65 zone->compact_defer_shift = COMPACT_MAX_DEFER_SHIFT; 66 } 67 68 /* Returns true if compaction should be skipped this time */ 69 static inline bool compaction_deferred(struct zone *zone, int order) 70 { 71 unsigned long defer_limit = 1UL << zone->compact_defer_shift; 72 73 if (order < zone->compact_order_failed) 74 return false; 75 76 /* Avoid possible overflow */ 77 if (++zone->compact_considered > defer_limit) 78 zone->compact_considered = defer_limit; 79 80 return zone->compact_considered < (1UL << zone->compact_defer_shift); 81 } 82 83 #else 84 static inline unsigned long try_to_compact_pages(struct zonelist *zonelist, 85 int order, gfp_t gfp_mask, nodemask_t *nodemask, 86 bool sync) 87 { 88 return COMPACT_CONTINUE; 89 } 90 91 static inline int compact_pgdat(pg_data_t *pgdat, int order) 92 { 93 return COMPACT_CONTINUE; 94 } 95 96 static inline unsigned long compaction_suitable(struct zone *zone, int order) 97 { 98 return COMPACT_SKIPPED; 99 } 100 101 static inline void defer_compaction(struct zone *zone, int order) 102 { 103 } 104 105 static inline bool compaction_deferred(struct zone *zone, int order) 106 { 107 return 1; 108 } 109 110 #endif /* CONFIG_COMPACTION */ 111 112 #if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA) 113 extern int compaction_register_node(struct node *node); 114 extern void compaction_unregister_node(struct node *node); 115 116 #else 117 118 static inline int compaction_register_node(struct node *node) 119 { 120 return 0; 121 } 122 123 static inline void compaction_unregister_node(struct node *node) 124 { 125 } 126 #endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */ 127 128 #endif /* _LINUX_COMPACTION_H */ 129