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 */
defer_compaction(struct zone * zone)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 */
compaction_deferred(struct zone * zone)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
try_to_compact_pages(struct zonelist * zonelist,int order,gfp_t gfp_mask,nodemask_t * nodemask,bool sync)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
compaction_suitable(struct zone * zone,int order)65 static inline unsigned long compaction_suitable(struct zone *zone, int order)
66 {
67 return COMPACT_SKIPPED;
68 }
69
defer_compaction(struct zone * zone)70 static inline void defer_compaction(struct zone *zone)
71 {
72 }
73
compaction_deferred(struct zone * zone)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
compaction_register_node(struct node * node)87 static inline int compaction_register_node(struct node *node)
88 {
89 return 0;
90 }
91
compaction_unregister_node(struct node * node)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