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 26 /* Do not skip compaction more than 64 times */ 27 #define COMPACT_MAX_DEFER_SHIFT 6 28 29 /* 30 * Compaction is deferred when compaction fails to result in a page 31 * allocation success. 1 << compact_defer_limit compactions are skipped up 32 * to a limit of 1 << COMPACT_MAX_DEFER_SHIFT 33 */ 34 static inline void defer_compaction(struct zone *zone) 35 { 36 zone->compact_considered = 0; 37 zone->compact_defer_shift++; 38 39 if (zone->compact_defer_shift > COMPACT_MAX_DEFER_SHIFT) 40 zone->compact_defer_shift = COMPACT_MAX_DEFER_SHIFT; 41 } 42 43 /* Returns true if compaction should be skipped this time */ 44 static inline bool compaction_deferred(struct zone *zone) 45 { 46 unsigned long defer_limit = 1UL << zone->compact_defer_shift; 47 48 /* Avoid possible overflow */ 49 if (++zone->compact_considered > defer_limit) 50 zone->compact_considered = defer_limit; 51 52 return zone->compact_considered < (1UL << zone->compact_defer_shift); 53 } 54 55 #else 56 static inline unsigned long try_to_compact_pages(struct zonelist *zonelist, 57 int order, gfp_t gfp_mask, nodemask_t *nodemask) 58 { 59 return COMPACT_CONTINUE; 60 } 61 62 static inline void defer_compaction(struct zone *zone) 63 { 64 } 65 66 static inline bool compaction_deferred(struct zone *zone) 67 { 68 return 1; 69 } 70 71 #endif /* CONFIG_COMPACTION */ 72 73 #if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA) 74 extern int compaction_register_node(struct node *node); 75 extern void compaction_unregister_node(struct node *node); 76 77 #else 78 79 static inline int compaction_register_node(struct node *node) 80 { 81 return 0; 82 } 83 84 static inline void compaction_unregister_node(struct node *node) 85 { 86 } 87 #endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */ 88 89 #endif /* _LINUX_COMPACTION_H */ 90