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 not possible or direct reclaim was more suitable */ 6 #define COMPACT_SKIPPED 0 7 /* compaction should continue to another pageblock */ 8 #define COMPACT_CONTINUE 1 9 /* direct compaction partially compacted a zone and there are suitable pages */ 10 #define COMPACT_PARTIAL 2 11 /* The full zone was compacted */ 12 #define COMPACT_COMPLETE 3 13 14 #ifdef CONFIG_COMPACTION 15 extern int sysctl_compact_memory; 16 extern int sysctl_compaction_handler(struct ctl_table *table, int write, 17 void __user *buffer, size_t *length, loff_t *ppos); 18 extern int sysctl_extfrag_threshold; 19 extern int sysctl_extfrag_handler(struct ctl_table *table, int write, 20 void __user *buffer, size_t *length, loff_t *ppos); 21 22 extern int fragmentation_index(struct zone *zone, unsigned int order); 23 extern unsigned long try_to_compact_pages(struct zonelist *zonelist, 24 int order, gfp_t gfp_mask, nodemask_t *mask, 25 bool sync); 26 extern unsigned long compaction_suitable(struct zone *zone, int order); 27 extern unsigned long compact_zone_order(struct zone *zone, int order, 28 gfp_t gfp_mask, bool sync); 29 30 /* Do not skip compaction more than 64 times */ 31 #define COMPACT_MAX_DEFER_SHIFT 6 32 33 /* 34 * Compaction is deferred when compaction fails to result in a page 35 * allocation success. 1 << compact_defer_limit compactions are skipped up 36 * to a limit of 1 << COMPACT_MAX_DEFER_SHIFT 37 */ 38 static inline void defer_compaction(struct zone *zone) 39 { 40 zone->compact_considered = 0; 41 zone->compact_defer_shift++; 42 43 if (zone->compact_defer_shift > COMPACT_MAX_DEFER_SHIFT) 44 zone->compact_defer_shift = COMPACT_MAX_DEFER_SHIFT; 45 } 46 47 /* Returns true if compaction should be skipped this time */ 48 static inline bool compaction_deferred(struct zone *zone) 49 { 50 unsigned long defer_limit = 1UL << zone->compact_defer_shift; 51 52 /* Avoid possible overflow */ 53 if (++zone->compact_considered > defer_limit) 54 zone->compact_considered = defer_limit; 55 56 return zone->compact_considered < (1UL << zone->compact_defer_shift); 57 } 58 59 #else 60 static inline unsigned long try_to_compact_pages(struct zonelist *zonelist, 61 int order, gfp_t gfp_mask, nodemask_t *nodemask, 62 bool sync) 63 { 64 return COMPACT_CONTINUE; 65 } 66 67 static inline unsigned long compaction_suitable(struct zone *zone, int order) 68 { 69 return COMPACT_SKIPPED; 70 } 71 72 static inline unsigned long compact_zone_order(struct zone *zone, int order, 73 gfp_t gfp_mask, bool sync) 74 { 75 return COMPACT_CONTINUE; 76 } 77 78 static inline void defer_compaction(struct zone *zone) 79 { 80 } 81 82 static inline bool compaction_deferred(struct zone *zone) 83 { 84 return 1; 85 } 86 87 #endif /* CONFIG_COMPACTION */ 88 89 #if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA) 90 extern int compaction_register_node(struct node *node); 91 extern void compaction_unregister_node(struct node *node); 92 93 #else 94 95 static inline int compaction_register_node(struct node *node) 96 { 97 return 0; 98 } 99 100 static inline void compaction_unregister_node(struct node *node) 101 { 102 } 103 #endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */ 104 105 #endif /* _LINUX_COMPACTION_H */ 106