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 28 /* Do not skip compaction more than 64 times */ 29 #define COMPACT_MAX_DEFER_SHIFT 6 30 31 /* 32 * Compaction is deferred when compaction fails to result in a page 33 * allocation success. 1 << compact_defer_limit compactions are skipped up 34 * to a limit of 1 << COMPACT_MAX_DEFER_SHIFT 35 */ 36 static inline void defer_compaction(struct zone *zone) 37 { 38 zone->compact_considered = 0; 39 zone->compact_defer_shift++; 40 41 if (zone->compact_defer_shift > COMPACT_MAX_DEFER_SHIFT) 42 zone->compact_defer_shift = COMPACT_MAX_DEFER_SHIFT; 43 } 44 45 /* Returns true if compaction should be skipped this time */ 46 static inline bool compaction_deferred(struct zone *zone) 47 { 48 unsigned long defer_limit = 1UL << zone->compact_defer_shift; 49 50 /* Avoid possible overflow */ 51 if (++zone->compact_considered > defer_limit) 52 zone->compact_considered = defer_limit; 53 54 return zone->compact_considered < (1UL << zone->compact_defer_shift); 55 } 56 57 #else 58 static inline unsigned long try_to_compact_pages(struct zonelist *zonelist, 59 int order, gfp_t gfp_mask, nodemask_t *nodemask, 60 bool sync) 61 { 62 return COMPACT_CONTINUE; 63 } 64 65 static inline unsigned long compaction_suitable(struct zone *zone, int order) 66 { 67 return COMPACT_SKIPPED; 68 } 69 70 static inline void defer_compaction(struct zone *zone) 71 { 72 } 73 74 static inline bool compaction_deferred(struct zone *zone) 75 { 76 return 1; 77 } 78 79 #endif /* CONFIG_COMPACTION */ 80 81 #if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA) 82 extern int compaction_register_node(struct node *node); 83 extern void compaction_unregister_node(struct node *node); 84 85 #else 86 87 static inline int compaction_register_node(struct node *node) 88 { 89 return 0; 90 } 91 92 static inline void compaction_unregister_node(struct node *node) 93 { 94 } 95 #endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */ 96 97 #endif /* _LINUX_COMPACTION_H */ 98