1 #ifndef _LINUX_COMPACTION_H
2 #define _LINUX_COMPACTION_H
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
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);
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, bool *contended);
26 extern int compact_pgdat(pg_data_t *pgdat, int order);
27 extern void reset_isolation_suitable(pg_data_t *pgdat);
28 extern unsigned long compaction_suitable(struct zone *zone, int order);
30 /* Do not skip compaction more than 64 times */
31 #define COMPACT_MAX_DEFER_SHIFT 6
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
38 static inline void defer_compaction(struct zone *zone, int order)
40 zone->compact_considered = 0;
41 zone->compact_defer_shift++;
43 if (order < zone->compact_order_failed)
44 zone->compact_order_failed = order;
46 if (zone->compact_defer_shift > COMPACT_MAX_DEFER_SHIFT)
47 zone->compact_defer_shift = COMPACT_MAX_DEFER_SHIFT;
50 /* Returns true if compaction should be skipped this time */
51 static inline bool compaction_deferred(struct zone *zone, int order)
53 unsigned long defer_limit = 1UL << zone->compact_defer_shift;
55 if (order < zone->compact_order_failed)
58 /* Avoid possible overflow */
59 if (++zone->compact_considered > defer_limit)
60 zone->compact_considered = defer_limit;
62 return zone->compact_considered < defer_limit;
65 /* Returns true if restarting compaction after many failures */
66 static inline bool compaction_restarting(struct zone *zone, int order)
68 if (order < zone->compact_order_failed)
71 return zone->compact_defer_shift == COMPACT_MAX_DEFER_SHIFT &&
72 zone->compact_considered >= 1UL << zone->compact_defer_shift;
76 static inline unsigned long try_to_compact_pages(struct zonelist *zonelist,
77 int order, gfp_t gfp_mask, nodemask_t *nodemask,
78 bool sync, bool *contended)
80 return COMPACT_CONTINUE;
83 static inline int compact_pgdat(pg_data_t *pgdat, int order)
85 return COMPACT_CONTINUE;
88 static inline void reset_isolation_suitable(pg_data_t *pgdat)
92 static inline unsigned long compaction_suitable(struct zone *zone, int order)
94 return COMPACT_SKIPPED;
97 static inline void defer_compaction(struct zone *zone, int order)
101 static inline bool compaction_deferred(struct zone *zone, int order)
106 #endif /* CONFIG_COMPACTION */
108 #if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
109 extern int compaction_register_node(struct node *node);
110 extern void compaction_unregister_node(struct node *node);
114 static inline int compaction_register_node(struct node *node)
119 static inline void compaction_unregister_node(struct node *node)
122 #endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */
124 #endif /* _LINUX_COMPACTION_H */