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
26/* Do not skip compaction more than 64 times */
27#define COMPACT_MAX_DEFER_SHIFT 6
28
29/*
30 * Compaction is deferred when compaction fails to result in a page
31 * allocation success. 1 << compact_defer_limit compactions are skipped up
32 * to a limit of 1 << COMPACT_MAX_DEFER_SHIFT
33 */
34static inline void defer_compaction(struct zone *zone)
35{
36 zone->compact_considered = 0;
37 zone->compact_defer_shift++;
38
39 if (zone->compact_defer_shift > COMPACT_MAX_DEFER_SHIFT)
40 zone->compact_defer_shift = COMPACT_MAX_DEFER_SHIFT;
41}
42
43/* Returns true if compaction should be skipped this time */
44static inline bool compaction_deferred(struct zone *zone)
45{
46 unsigned long defer_limit = 1UL << zone->compact_defer_shift;
47
48 /* Avoid possible overflow */
49 if (++zone->compact_considered > defer_limit)
50 zone->compact_considered = defer_limit;
51
52 return zone->compact_considered < (1UL << zone->compact_defer_shift);
53}
54
55#else
56static inline unsigned long try_to_compact_pages(struct zonelist *zonelist,
57 int order, gfp_t gfp_mask, nodemask_t *nodemask)
58{
59 return COMPACT_CONTINUE;
60}
61
62static inline void defer_compaction(struct zone *zone)
63{
64}
65
66static inline bool compaction_deferred(struct zone *zone)
67{
68 return 1;
69}
70
71#endif /* CONFIG_COMPACTION */
72
73#if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
74extern int compaction_register_node(struct node *node);
75extern void compaction_unregister_node(struct node *node);
76
77#else
78
79static inline int compaction_register_node(struct node *node)
80{
81 return 0;
82}
83
84static inline void compaction_unregister_node(struct node *node)
85{
86}
87#endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */
88
89#endif /* _LINUX_COMPACTION_H */