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 extern unsigned long compact_zone_order(struct zone *zone, int order,
28 gfp_t gfp_mask, bool sync);
29
30 /* Do not skip compaction more than 64 times */
31 #define COMPACT_MAX_DEFER_SHIFT 6
32
33 /*
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
37 */
defer_compaction(struct zone * zone)38 static inline void defer_compaction(struct zone *zone)
39 {
40 zone->compact_considered = 0;
41 zone->compact_defer_shift++;
42
43 if (zone->compact_defer_shift > COMPACT_MAX_DEFER_SHIFT)
44 zone->compact_defer_shift = COMPACT_MAX_DEFER_SHIFT;
45 }
46
47 /* Returns true if compaction should be skipped this time */
compaction_deferred(struct zone * zone)48 static inline bool compaction_deferred(struct zone *zone)
49 {
50 unsigned long defer_limit = 1UL << zone->compact_defer_shift;
51
52 /* Avoid possible overflow */
53 if (++zone->compact_considered > defer_limit)
54 zone->compact_considered = defer_limit;
55
56 return zone->compact_considered < (1UL << zone->compact_defer_shift);
57 }
58
59 #else
try_to_compact_pages(struct zonelist * zonelist,int order,gfp_t gfp_mask,nodemask_t * nodemask,bool sync)60 static inline unsigned long try_to_compact_pages(struct zonelist *zonelist,
61 int order, gfp_t gfp_mask, nodemask_t *nodemask,
62 bool sync)
63 {
64 return COMPACT_CONTINUE;
65 }
66
compaction_suitable(struct zone * zone,int order)67 static inline unsigned long compaction_suitable(struct zone *zone, int order)
68 {
69 return COMPACT_SKIPPED;
70 }
71
compact_zone_order(struct zone * zone,int order,gfp_t gfp_mask,bool sync)72 static inline unsigned long compact_zone_order(struct zone *zone, int order,
73 gfp_t gfp_mask, bool sync)
74 {
75 return COMPACT_CONTINUE;
76 }
77
defer_compaction(struct zone * zone)78 static inline void defer_compaction(struct zone *zone)
79 {
80 }
81
compaction_deferred(struct zone * zone)82 static inline bool compaction_deferred(struct zone *zone)
83 {
84 return 1;
85 }
86
87 #endif /* CONFIG_COMPACTION */
88
89 #if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
90 extern int compaction_register_node(struct node *node);
91 extern void compaction_unregister_node(struct node *node);
92
93 #else
94
compaction_register_node(struct node * node)95 static inline int compaction_register_node(struct node *node)
96 {
97 return 0;
98 }
99
compaction_unregister_node(struct node * node)100 static inline void compaction_unregister_node(struct node *node)
101 {
102 }
103 #endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */
104
105 #endif /* _LINUX_COMPACTION_H */
106