Linux kernel mirror (for testing)
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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#define COMPACT_MODE_DIRECT_RECLAIM 0
15#define COMPACT_MODE_KSWAPD 1
16
17#ifdef CONFIG_COMPACTION
18extern int sysctl_compact_memory;
19extern int sysctl_compaction_handler(struct ctl_table *table, int write,
20 void __user *buffer, size_t *length, loff_t *ppos);
21extern int sysctl_extfrag_threshold;
22extern int sysctl_extfrag_handler(struct ctl_table *table, int write,
23 void __user *buffer, size_t *length, loff_t *ppos);
24
25extern int fragmentation_index(struct zone *zone, unsigned int order);
26extern unsigned long try_to_compact_pages(struct zonelist *zonelist,
27 int order, gfp_t gfp_mask, nodemask_t *mask,
28 bool sync);
29extern unsigned long compaction_suitable(struct zone *zone, int order);
30extern unsigned long compact_zone_order(struct zone *zone, int order,
31 gfp_t gfp_mask, bool sync,
32 int compact_mode);
33
34/* Do not skip compaction more than 64 times */
35#define COMPACT_MAX_DEFER_SHIFT 6
36
37/*
38 * Compaction is deferred when compaction fails to result in a page
39 * allocation success. 1 << compact_defer_limit compactions are skipped up
40 * to a limit of 1 << COMPACT_MAX_DEFER_SHIFT
41 */
42static inline void defer_compaction(struct zone *zone)
43{
44 zone->compact_considered = 0;
45 zone->compact_defer_shift++;
46
47 if (zone->compact_defer_shift > COMPACT_MAX_DEFER_SHIFT)
48 zone->compact_defer_shift = COMPACT_MAX_DEFER_SHIFT;
49}
50
51/* Returns true if compaction should be skipped this time */
52static inline bool compaction_deferred(struct zone *zone)
53{
54 unsigned long defer_limit = 1UL << zone->compact_defer_shift;
55
56 /* Avoid possible overflow */
57 if (++zone->compact_considered > defer_limit)
58 zone->compact_considered = defer_limit;
59
60 return zone->compact_considered < (1UL << zone->compact_defer_shift);
61}
62
63#else
64static inline unsigned long try_to_compact_pages(struct zonelist *zonelist,
65 int order, gfp_t gfp_mask, nodemask_t *nodemask,
66 bool sync)
67{
68 return COMPACT_CONTINUE;
69}
70
71static inline unsigned long compaction_suitable(struct zone *zone, int order)
72{
73 return COMPACT_SKIPPED;
74}
75
76static inline unsigned long compact_zone_order(struct zone *zone, int order,
77 gfp_t gfp_mask, bool sync,
78 int compact_mode)
79{
80 return COMPACT_CONTINUE;
81}
82
83static inline void defer_compaction(struct zone *zone)
84{
85}
86
87static inline bool compaction_deferred(struct zone *zone)
88{
89 return 1;
90}
91
92#endif /* CONFIG_COMPACTION */
93
94#if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
95extern int compaction_register_node(struct node *node);
96extern void compaction_unregister_node(struct node *node);
97
98#else
99
100static inline int compaction_register_node(struct node *node)
101{
102 return 0;
103}
104
105static inline void compaction_unregister_node(struct node *node)
106{
107}
108#endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */
109
110#endif /* _LINUX_COMPACTION_H */