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
16 /* Used to signal whether compaction detected need_sched() or lock contention */
17 /* No contention detected */
18 #define COMPACT_CONTENDED_NONE 0
19 /* Either need_sched() was true or fatal signal pending */
20 #define COMPACT_CONTENDED_SCHED 1
21 /* Zone lock or lru_lock was contended in async compaction */
22 #define COMPACT_CONTENDED_LOCK 2
24 struct alloc_context; /* in mm/internal.h */
26 #ifdef CONFIG_COMPACTION
27 extern int sysctl_compact_memory;
28 extern int sysctl_compaction_handler(struct ctl_table *table, int write,
29 void __user *buffer, size_t *length, loff_t *ppos);
30 extern int sysctl_extfrag_threshold;
31 extern int sysctl_extfrag_handler(struct ctl_table *table, int write,
32 void __user *buffer, size_t *length, loff_t *ppos);
34 extern int fragmentation_index(struct zone *zone, unsigned int order);
35 extern unsigned long try_to_compact_pages(gfp_t gfp_mask, unsigned int order,
36 int alloc_flags, const struct alloc_context *ac,
37 enum migrate_mode mode, int *contended);
38 extern void compact_pgdat(pg_data_t *pgdat, int order);
39 extern void reset_isolation_suitable(pg_data_t *pgdat);
40 extern unsigned long compaction_suitable(struct zone *zone, int order,
41 int alloc_flags, int classzone_idx);
43 /* Do not skip compaction more than 64 times */
44 #define COMPACT_MAX_DEFER_SHIFT 6
47 * Compaction is deferred when compaction fails to result in a page
48 * allocation success. 1 << compact_defer_limit compactions are skipped up
49 * to a limit of 1 << COMPACT_MAX_DEFER_SHIFT
51 static inline void defer_compaction(struct zone *zone, int order)
53 zone->compact_considered = 0;
54 zone->compact_defer_shift++;
56 if (order < zone->compact_order_failed)
57 zone->compact_order_failed = order;
59 if (zone->compact_defer_shift > COMPACT_MAX_DEFER_SHIFT)
60 zone->compact_defer_shift = COMPACT_MAX_DEFER_SHIFT;
63 /* Returns true if compaction should be skipped this time */
64 static inline bool compaction_deferred(struct zone *zone, int order)
66 unsigned long defer_limit = 1UL << zone->compact_defer_shift;
68 if (order < zone->compact_order_failed)
71 /* Avoid possible overflow */
72 if (++zone->compact_considered > defer_limit)
73 zone->compact_considered = defer_limit;
75 return zone->compact_considered < defer_limit;
79 * Update defer tracking counters after successful compaction of given order,
80 * which means an allocation either succeeded (alloc_success == true) or is
81 * expected to succeed.
83 static inline void compaction_defer_reset(struct zone *zone, int order,
87 zone->compact_considered = 0;
88 zone->compact_defer_shift = 0;
90 if (order >= zone->compact_order_failed)
91 zone->compact_order_failed = order + 1;
94 /* Returns true if restarting compaction after many failures */
95 static inline bool compaction_restarting(struct zone *zone, int order)
97 if (order < zone->compact_order_failed)
100 return zone->compact_defer_shift == COMPACT_MAX_DEFER_SHIFT &&
101 zone->compact_considered >= 1UL << zone->compact_defer_shift;
105 static inline unsigned long try_to_compact_pages(gfp_t gfp_mask,
106 unsigned int order, int alloc_flags,
107 const struct alloc_context *ac,
108 enum migrate_mode mode, int *contended)
110 return COMPACT_CONTINUE;
113 static inline void compact_pgdat(pg_data_t *pgdat, int order)
117 static inline void reset_isolation_suitable(pg_data_t *pgdat)
121 static inline unsigned long compaction_suitable(struct zone *zone, int order,
122 int alloc_flags, int classzone_idx)
124 return COMPACT_SKIPPED;
127 static inline void defer_compaction(struct zone *zone, int order)
131 static inline bool compaction_deferred(struct zone *zone, int order)
136 #endif /* CONFIG_COMPACTION */
138 #if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
139 extern int compaction_register_node(struct node *node);
140 extern void compaction_unregister_node(struct node *node);
144 static inline int compaction_register_node(struct node *node)
149 static inline void compaction_unregister_node(struct node *node)
152 #endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */
154 #endif /* _LINUX_COMPACTION_H */