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#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 int compact_pgdat(pg_data_t *pgdat, int order);
27extern unsigned long compaction_suitable(struct zone *zone, int order);
28
29/* Do not skip compaction more than 64 times */
30#define COMPACT_MAX_DEFER_SHIFT 6
31
32/*
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
36 */
37static inline void defer_compaction(struct zone *zone, int order)
38{
39 zone->compact_considered = 0;
40 zone->compact_defer_shift++;
41
42 if (order < zone->compact_order_failed)
43 zone->compact_order_failed = order;
44
45 if (zone->compact_defer_shift > COMPACT_MAX_DEFER_SHIFT)
46 zone->compact_defer_shift = COMPACT_MAX_DEFER_SHIFT;
47}
48
49/* Returns true if compaction should be skipped this time */
50static inline bool compaction_deferred(struct zone *zone, int order)
51{
52 unsigned long defer_limit = 1UL << zone->compact_defer_shift;
53
54 if (order < zone->compact_order_failed)
55 return false;
56
57 /* Avoid possible overflow */
58 if (++zone->compact_considered > defer_limit)
59 zone->compact_considered = defer_limit;
60
61 return zone->compact_considered < defer_limit;
62}
63
64#else
65static inline unsigned long try_to_compact_pages(struct zonelist *zonelist,
66 int order, gfp_t gfp_mask, nodemask_t *nodemask,
67 bool sync)
68{
69 return COMPACT_CONTINUE;
70}
71
72static inline int compact_pgdat(pg_data_t *pgdat, int order)
73{
74 return COMPACT_CONTINUE;
75}
76
77static inline unsigned long compaction_suitable(struct zone *zone, int order)
78{
79 return COMPACT_SKIPPED;
80}
81
82static inline void defer_compaction(struct zone *zone, int order)
83{
84}
85
86static inline bool compaction_deferred(struct zone *zone, int order)
87{
88 return true;
89}
90
91#endif /* CONFIG_COMPACTION */
92
93#if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
94extern int compaction_register_node(struct node *node);
95extern void compaction_unregister_node(struct node *node);
96
97#else
98
99static inline int compaction_register_node(struct node *node)
100{
101 return 0;
102}
103
104static inline void compaction_unregister_node(struct node *node)
105{
106}
107#endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */
108
109#endif /* _LINUX_COMPACTION_H */