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 #ifdef CONFIG_COMPACTION
25 extern int sysctl_compact_memory;
26 extern int sysctl_compaction_handler(struct ctl_table *table, int write,
27 void __user *buffer, size_t *length, loff_t *ppos);
28 extern int sysctl_extfrag_threshold;
29 extern int sysctl_extfrag_handler(struct ctl_table *table, int write,
30 void __user *buffer, size_t *length, loff_t *ppos);
32 extern int fragmentation_index(struct zone *zone, unsigned int order);
33 extern unsigned long try_to_compact_pages(struct zonelist *zonelist,
34 int order, gfp_t gfp_mask, nodemask_t *mask,
35 enum migrate_mode mode, int *contended,
36 struct zone **candidate_zone);
37 extern void compact_pgdat(pg_data_t *pgdat, int order);
38 extern void reset_isolation_suitable(pg_data_t *pgdat);
39 extern unsigned long compaction_suitable(struct zone *zone, int order);
41 /* Do not skip compaction more than 64 times */
42 #define COMPACT_MAX_DEFER_SHIFT 6
45 * Compaction is deferred when compaction fails to result in a page
46 * allocation success. 1 << compact_defer_limit compactions are skipped up
47 * to a limit of 1 << COMPACT_MAX_DEFER_SHIFT
49 static inline void defer_compaction(struct zone *zone, int order)
51 zone->compact_considered = 0;
52 zone->compact_defer_shift++;
54 if (order < zone->compact_order_failed)
55 zone->compact_order_failed = order;
57 if (zone->compact_defer_shift > COMPACT_MAX_DEFER_SHIFT)
58 zone->compact_defer_shift = COMPACT_MAX_DEFER_SHIFT;
61 /* Returns true if compaction should be skipped this time */
62 static inline bool compaction_deferred(struct zone *zone, int order)
64 unsigned long defer_limit = 1UL << zone->compact_defer_shift;
66 if (order < zone->compact_order_failed)
69 /* Avoid possible overflow */
70 if (++zone->compact_considered > defer_limit)
71 zone->compact_considered = defer_limit;
73 return zone->compact_considered < defer_limit;
77 * Update defer tracking counters after successful compaction of given order,
78 * which means an allocation either succeeded (alloc_success == true) or is
79 * expected to succeed.
81 static inline void compaction_defer_reset(struct zone *zone, int order,
85 zone->compact_considered = 0;
86 zone->compact_defer_shift = 0;
88 if (order >= zone->compact_order_failed)
89 zone->compact_order_failed = order + 1;
92 /* Returns true if restarting compaction after many failures */
93 static inline bool compaction_restarting(struct zone *zone, int order)
95 if (order < zone->compact_order_failed)
98 return zone->compact_defer_shift == COMPACT_MAX_DEFER_SHIFT &&
99 zone->compact_considered >= 1UL << zone->compact_defer_shift;
103 static inline unsigned long try_to_compact_pages(struct zonelist *zonelist,
104 int order, gfp_t gfp_mask, nodemask_t *nodemask,
105 enum migrate_mode mode, int *contended,
106 struct zone **candidate_zone)
108 return COMPACT_CONTINUE;
111 static inline void compact_pgdat(pg_data_t *pgdat, int order)
115 static inline void reset_isolation_suitable(pg_data_t *pgdat)
119 static inline unsigned long compaction_suitable(struct zone *zone, int order)
121 return COMPACT_SKIPPED;
124 static inline void defer_compaction(struct zone *zone, int order)
128 static inline bool compaction_deferred(struct zone *zone, int order)
133 #endif /* CONFIG_COMPACTION */
135 #if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
136 extern int compaction_register_node(struct node *node);
137 extern void compaction_unregister_node(struct node *node);
141 static inline int compaction_register_node(struct node *node)
146 static inline void compaction_unregister_node(struct node *node)
149 #endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */
151 #endif /* _LINUX_COMPACTION_H */