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 int alloc_flags, int classzone_idx); 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 int alloc_flags, int classzone_idx); 41 42 /* Do not skip compaction more than 64 times */ 43 #define COMPACT_MAX_DEFER_SHIFT 6 44 45 /* 46 * Compaction is deferred when compaction fails to result in a page 47 * allocation success. 1 << compact_defer_limit compactions are skipped up 48 * to a limit of 1 << COMPACT_MAX_DEFER_SHIFT 49 */ 50 static inline void defer_compaction(struct zone *zone, int order) 51 { 52 zone->compact_considered = 0; 53 zone->compact_defer_shift++; 54 55 if (order < zone->compact_order_failed) 56 zone->compact_order_failed = order; 57 58 if (zone->compact_defer_shift > COMPACT_MAX_DEFER_SHIFT) 59 zone->compact_defer_shift = COMPACT_MAX_DEFER_SHIFT; 60 } 61 62 /* Returns true if compaction should be skipped this time */ 63 static inline bool compaction_deferred(struct zone *zone, int order) 64 { 65 unsigned long defer_limit = 1UL << zone->compact_defer_shift; 66 67 if (order < zone->compact_order_failed) 68 return false; 69 70 /* Avoid possible overflow */ 71 if (++zone->compact_considered > defer_limit) 72 zone->compact_considered = defer_limit; 73 74 return zone->compact_considered < defer_limit; 75 } 76 77 /* 78 * Update defer tracking counters after successful compaction of given order, 79 * which means an allocation either succeeded (alloc_success == true) or is 80 * expected to succeed. 81 */ 82 static inline void compaction_defer_reset(struct zone *zone, int order, 83 bool alloc_success) 84 { 85 if (alloc_success) { 86 zone->compact_considered = 0; 87 zone->compact_defer_shift = 0; 88 } 89 if (order >= zone->compact_order_failed) 90 zone->compact_order_failed = order + 1; 91 } 92 93 /* Returns true if restarting compaction after many failures */ 94 static inline bool compaction_restarting(struct zone *zone, int order) 95 { 96 if (order < zone->compact_order_failed) 97 return false; 98 99 return zone->compact_defer_shift == COMPACT_MAX_DEFER_SHIFT && 100 zone->compact_considered >= 1UL << zone->compact_defer_shift; 101 } 102 103 #else 104 static inline unsigned long try_to_compact_pages(struct zonelist *zonelist, 105 int order, gfp_t gfp_mask, nodemask_t *nodemask, 106 enum migrate_mode mode, int *contended, 107 int alloc_flags, int classzone_idx) 108 { 109 return COMPACT_CONTINUE; 110 } 111 112 static inline void compact_pgdat(pg_data_t *pgdat, int order) 113 { 114 } 115 116 static inline void reset_isolation_suitable(pg_data_t *pgdat) 117 { 118 } 119 120 static inline unsigned long compaction_suitable(struct zone *zone, int order, 121 int alloc_flags, int classzone_idx) 122 { 123 return COMPACT_SKIPPED; 124 } 125 126 static inline void defer_compaction(struct zone *zone, int order) 127 { 128 } 129 130 static inline bool compaction_deferred(struct zone *zone, int order) 131 { 132 return true; 133 } 134 135 #endif /* CONFIG_COMPACTION */ 136 137 #if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA) 138 extern int compaction_register_node(struct node *node); 139 extern void compaction_unregister_node(struct node *node); 140 141 #else 142 143 static inline int compaction_register_node(struct node *node) 144 { 145 return 0; 146 } 147 148 static inline void compaction_unregister_node(struct node *node) 149 { 150 } 151 #endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */ 152 153 #endif /* _LINUX_COMPACTION_H */ 154