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 extern unsigned long compaction_suitable(struct zone *zone, int order);
26 extern unsigned long compact_zone_order(struct zone *zone, int order,
29 /* Do not skip compaction more than 64 times */
30 #define COMPACT_MAX_DEFER_SHIFT 6
33 * Compaction is deferred when compaction fails to result in a page
34 * allocation success. 1 << compact_defer_limit compactions are skipped up
35 * to a limit of 1 << COMPACT_MAX_DEFER_SHIFT
37 static inline void defer_compaction(struct zone *zone)
39 zone->compact_considered = 0;
40 zone->compact_defer_shift++;
42 if (zone->compact_defer_shift > COMPACT_MAX_DEFER_SHIFT)
43 zone->compact_defer_shift = COMPACT_MAX_DEFER_SHIFT;
46 /* Returns true if compaction should be skipped this time */
47 static inline bool compaction_deferred(struct zone *zone)
49 unsigned long defer_limit = 1UL << zone->compact_defer_shift;
51 /* Avoid possible overflow */
52 if (++zone->compact_considered > defer_limit)
53 zone->compact_considered = defer_limit;
55 return zone->compact_considered < (1UL << zone->compact_defer_shift);
59 static inline unsigned long try_to_compact_pages(struct zonelist *zonelist,
60 int order, gfp_t gfp_mask, nodemask_t *nodemask)
62 return COMPACT_CONTINUE;
65 static inline unsigned long compaction_suitable(struct zone *zone, int order)
67 return COMPACT_SKIPPED;
70 static inline unsigned long compact_zone_order(struct zone *zone, int order,
76 static inline void defer_compaction(struct zone *zone)
80 static inline bool compaction_deferred(struct zone *zone)
85 #endif /* CONFIG_COMPACTION */
87 #if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
88 extern int compaction_register_node(struct node *node);
89 extern void compaction_unregister_node(struct node *node);
93 static inline int compaction_register_node(struct node *node)
98 static inline void compaction_unregister_node(struct node *node)
101 #endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */
103 #endif /* _LINUX_COMPACTION_H */