1 #ifndef _LINUX_COMPACTION_H 2 #define _LINUX_COMPACTION_H 3 4 /* Return values for compact_zone() and try_to_compact_pages() */ 5 /* compaction didn't start as it was deferred due to past failures */ 6 #define COMPACT_DEFERRED 0 7 /* compaction didn't start as it was not possible or direct reclaim was more suitable */ 8 #define COMPACT_SKIPPED 1 9 /* compaction should continue to another pageblock */ 10 #define COMPACT_CONTINUE 2 11 /* direct compaction partially compacted a zone and there are suitable pages */ 12 #define COMPACT_PARTIAL 3 13 /* The full zone was compacted */ 14 #define COMPACT_COMPLETE 4 15 16 /* Used to signal whether compaction detected need_sched() or lock contention */ 17 /* No contention detected */ 18 #define COMPACT_CONTENDED_NONE 0 19 /* Either need_sched() was true or fatal signal pending */ 20 #define COMPACT_CONTENDED_SCHED 1 21 /* Zone lock or lru_lock was contended in async compaction */ 22 #define COMPACT_CONTENDED_LOCK 2 23 24 #ifdef CONFIG_COMPACTION 25 extern int sysctl_compact_memory; 26 extern int sysctl_compaction_handler(struct ctl_table *table, int write, 27 void __user *buffer, size_t *length, loff_t *ppos); 28 extern int sysctl_extfrag_threshold; 29 extern int sysctl_extfrag_handler(struct ctl_table *table, int write, 30 void __user *buffer, size_t *length, loff_t *ppos); 31 32 extern int fragmentation_index(struct zone *zone, unsigned int order); 33 extern unsigned long try_to_compact_pages(struct zonelist *zonelist, 34 int order, gfp_t gfp_mask, nodemask_t *mask, 35 enum migrate_mode mode, int *contended, 36 struct zone **candidate_zone); 37 extern void compact_pgdat(pg_data_t *pgdat, int order); 38 extern void reset_isolation_suitable(pg_data_t *pgdat); 39 extern unsigned long compaction_suitable(struct zone *zone, int order); 40 41 /* Do not skip compaction more than 64 times */ 42 #define COMPACT_MAX_DEFER_SHIFT 6 43 44 /* 45 * Compaction is deferred when compaction fails to result in a page 46 * allocation success. 1 << compact_defer_limit compactions are skipped up 47 * to a limit of 1 << COMPACT_MAX_DEFER_SHIFT 48 */ 49 static inline void defer_compaction(struct zone *zone, int order) 50 { 51 zone->compact_considered = 0; 52 zone->compact_defer_shift++; 53 54 if (order < zone->compact_order_failed) 55 zone->compact_order_failed = order; 56 57 if (zone->compact_defer_shift > COMPACT_MAX_DEFER_SHIFT) 58 zone->compact_defer_shift = COMPACT_MAX_DEFER_SHIFT; 59 } 60 61 /* Returns true if compaction should be skipped this time */ 62 static inline bool compaction_deferred(struct zone *zone, int order) 63 { 64 unsigned long defer_limit = 1UL << zone->compact_defer_shift; 65 66 if (order < zone->compact_order_failed) 67 return false; 68 69 /* Avoid possible overflow */ 70 if (++zone->compact_considered > defer_limit) 71 zone->compact_considered = defer_limit; 72 73 return zone->compact_considered < defer_limit; 74 } 75 76 /* 77 * Update defer tracking counters after successful compaction of given order, 78 * which means an allocation either succeeded (alloc_success == true) or is 79 * expected to succeed. 80 */ 81 static inline void compaction_defer_reset(struct zone *zone, int order, 82 bool alloc_success) 83 { 84 if (alloc_success) { 85 zone->compact_considered = 0; 86 zone->compact_defer_shift = 0; 87 } 88 if (order >= zone->compact_order_failed) 89 zone->compact_order_failed = order + 1; 90 } 91 92 /* Returns true if restarting compaction after many failures */ 93 static inline bool compaction_restarting(struct zone *zone, int order) 94 { 95 if (order < zone->compact_order_failed) 96 return false; 97 98 return zone->compact_defer_shift == COMPACT_MAX_DEFER_SHIFT && 99 zone->compact_considered >= 1UL << zone->compact_defer_shift; 100 } 101 102 #else 103 static inline unsigned long try_to_compact_pages(struct zonelist *zonelist, 104 int order, gfp_t gfp_mask, nodemask_t *nodemask, 105 enum migrate_mode mode, int *contended, 106 struct zone **candidate_zone) 107 { 108 return COMPACT_CONTINUE; 109 } 110 111 static inline void compact_pgdat(pg_data_t *pgdat, int order) 112 { 113 } 114 115 static inline void reset_isolation_suitable(pg_data_t *pgdat) 116 { 117 } 118 119 static inline unsigned long compaction_suitable(struct zone *zone, int order) 120 { 121 return COMPACT_SKIPPED; 122 } 123 124 static inline void defer_compaction(struct zone *zone, int order) 125 { 126 } 127 128 static inline bool compaction_deferred(struct zone *zone, int order) 129 { 130 return true; 131 } 132 133 #endif /* CONFIG_COMPACTION */ 134 135 #if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA) 136 extern int compaction_register_node(struct node *node); 137 extern void compaction_unregister_node(struct node *node); 138 139 #else 140 141 static inline int compaction_register_node(struct node *node) 142 { 143 return 0; 144 } 145 146 static inline void compaction_unregister_node(struct node *node) 147 { 148 } 149 #endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */ 150 151 #endif /* _LINUX_COMPACTION_H */ 152