1 #ifndef _LINUX_COMPACTION_H
2 #define _LINUX_COMPACTION_H
4 /* Return values for compact_zone() and try_to_compact_pages() */
5 /* compaction didn't start as it was deferred due to past failures */
6 #define COMPACT_DEFERRED 0
7 /* compaction didn't start as it was not possible or direct reclaim was more suitable */
8 #define COMPACT_SKIPPED 1
9 /* compaction should continue to another pageblock */
10 #define COMPACT_CONTINUE 2
11 /* direct compaction partially compacted a zone and there are suitable pages */
12 #define COMPACT_PARTIAL 3
13 /* The full zone was compacted */
14 #define COMPACT_COMPLETE 4
15 /* When adding new state, please change compaction_status_string, too */
17 /* Used to signal whether compaction detected need_sched() or lock contention */
18 /* No contention detected */
19 #define COMPACT_CONTENDED_NONE 0
20 /* Either need_sched() was true or fatal signal pending */
21 #define COMPACT_CONTENDED_SCHED 1
22 /* Zone lock or lru_lock was contended in async compaction */
23 #define COMPACT_CONTENDED_LOCK 2
25 struct alloc_context; /* in mm/internal.h */
27 #ifdef CONFIG_COMPACTION
28 extern int sysctl_compact_memory;
29 extern int sysctl_compaction_handler(struct ctl_table *table, int write,
30 void __user *buffer, size_t *length, loff_t *ppos);
31 extern int sysctl_extfrag_threshold;
32 extern int sysctl_extfrag_handler(struct ctl_table *table, int write,
33 void __user *buffer, size_t *length, loff_t *ppos);
35 extern int fragmentation_index(struct zone *zone, unsigned int order);
36 extern unsigned long try_to_compact_pages(gfp_t gfp_mask, unsigned int order,
37 int alloc_flags, const struct alloc_context *ac,
38 enum migrate_mode mode, int *contended);
39 extern void compact_pgdat(pg_data_t *pgdat, int order);
40 extern void reset_isolation_suitable(pg_data_t *pgdat);
41 extern unsigned long compaction_suitable(struct zone *zone, int order,
42 int alloc_flags, int classzone_idx);
44 /* Do not skip compaction more than 64 times */
45 #define COMPACT_MAX_DEFER_SHIFT 6
48 * Compaction is deferred when compaction fails to result in a page
49 * allocation success. 1 << compact_defer_limit compactions are skipped up
50 * to a limit of 1 << COMPACT_MAX_DEFER_SHIFT
52 static inline void defer_compaction(struct zone *zone, int order)
54 zone->compact_considered = 0;
55 zone->compact_defer_shift++;
57 if (order < zone->compact_order_failed)
58 zone->compact_order_failed = order;
60 if (zone->compact_defer_shift > COMPACT_MAX_DEFER_SHIFT)
61 zone->compact_defer_shift = COMPACT_MAX_DEFER_SHIFT;
64 /* Returns true if compaction should be skipped this time */
65 static inline bool compaction_deferred(struct zone *zone, int order)
67 unsigned long defer_limit = 1UL << zone->compact_defer_shift;
69 if (order < zone->compact_order_failed)
72 /* Avoid possible overflow */
73 if (++zone->compact_considered > defer_limit)
74 zone->compact_considered = defer_limit;
76 return zone->compact_considered < defer_limit;
80 * Update defer tracking counters after successful compaction of given order,
81 * which means an allocation either succeeded (alloc_success == true) or is
82 * expected to succeed.
84 static inline void compaction_defer_reset(struct zone *zone, int order,
88 zone->compact_considered = 0;
89 zone->compact_defer_shift = 0;
91 if (order >= zone->compact_order_failed)
92 zone->compact_order_failed = order + 1;
95 /* Returns true if restarting compaction after many failures */
96 static inline bool compaction_restarting(struct zone *zone, int order)
98 if (order < zone->compact_order_failed)
101 return zone->compact_defer_shift == COMPACT_MAX_DEFER_SHIFT &&
102 zone->compact_considered >= 1UL << zone->compact_defer_shift;
106 static inline unsigned long try_to_compact_pages(gfp_t gfp_mask,
107 unsigned int order, int alloc_flags,
108 const struct alloc_context *ac,
109 enum migrate_mode mode, int *contended)
111 return COMPACT_CONTINUE;
114 static inline void compact_pgdat(pg_data_t *pgdat, int order)
118 static inline void reset_isolation_suitable(pg_data_t *pgdat)
122 static inline unsigned long compaction_suitable(struct zone *zone, int order,
123 int alloc_flags, int classzone_idx)
125 return COMPACT_SKIPPED;
128 static inline void defer_compaction(struct zone *zone, int order)
132 static inline bool compaction_deferred(struct zone *zone, int order)
137 #endif /* CONFIG_COMPACTION */
139 #if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
140 extern int compaction_register_node(struct node *node);
141 extern void compaction_unregister_node(struct node *node);
145 static inline int compaction_register_node(struct node *node)
150 static inline void compaction_unregister_node(struct node *node)
153 #endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */
155 #endif /* _LINUX_COMPACTION_H */