Linux kernel mirror (for testing)
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linux
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
15extern int sysctl_compact_memory;
16extern int sysctl_compaction_handler(struct ctl_table *table, int write,
17 void __user *buffer, size_t *length, loff_t *ppos);
18extern int sysctl_extfrag_threshold;
19extern int sysctl_extfrag_handler(struct ctl_table *table, int write,
20 void __user *buffer, size_t *length, loff_t *ppos);
21
22extern int fragmentation_index(struct zone *zone, unsigned int order);
23extern unsigned long try_to_compact_pages(struct zonelist *zonelist,
24 int order, gfp_t gfp_mask, nodemask_t *mask,
25 bool sync);
26extern 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 */
36static 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 */
46static 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
58static 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
65static inline unsigned long compaction_suitable(struct zone *zone, int order)
66{
67 return COMPACT_SKIPPED;
68}
69
70static inline void defer_compaction(struct zone *zone)
71{
72}
73
74static 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)
82extern int compaction_register_node(struct node *node);
83extern void compaction_unregister_node(struct node *node);
84
85#else
86
87static inline int compaction_register_node(struct node *node)
88{
89 return 0;
90}
91
92static inline void compaction_unregister_node(struct node *node)
93{
94}
95#endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */
96
97#endif /* _LINUX_COMPACTION_H */