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 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
14 #ifdef CONFIG_COMPACTION
15 extern int sysctl_compact_memory
;
16 extern int sysctl_compaction_handler(struct ctl_table
*table
, int write
,
17 void __user
*buffer
, size_t *length
, loff_t
*ppos
);
18 extern int sysctl_extfrag_threshold
;
19 extern int sysctl_extfrag_handler(struct ctl_table
*table
, int write
,
20 void __user
*buffer
, size_t *length
, loff_t
*ppos
);
22 extern int fragmentation_index(struct zone
*zone
, unsigned int order
);
23 extern unsigned long try_to_compact_pages(struct zonelist
*zonelist
,
24 int order
, gfp_t gfp_mask
, nodemask_t
*mask
,
25 bool sync
, bool *contended
);
26 extern void compact_pgdat(pg_data_t
*pgdat
, int order
);
27 extern void reset_isolation_suitable(pg_data_t
*pgdat
);
28 extern unsigned long compaction_suitable(struct zone
*zone
, int order
);
30 /* Do not skip compaction more than 64 times */
31 #define COMPACT_MAX_DEFER_SHIFT 6
34 * Compaction is deferred when compaction fails to result in a page
35 * allocation success. 1 << compact_defer_limit compactions are skipped up
36 * to a limit of 1 << COMPACT_MAX_DEFER_SHIFT
38 static inline void defer_compaction(struct zone
*zone
, int order
)
40 zone
->compact_considered
= 0;
41 zone
->compact_defer_shift
++;
43 if (order
< zone
->compact_order_failed
)
44 zone
->compact_order_failed
= order
;
46 if (zone
->compact_defer_shift
> COMPACT_MAX_DEFER_SHIFT
)
47 zone
->compact_defer_shift
= COMPACT_MAX_DEFER_SHIFT
;
50 /* Returns true if compaction should be skipped this time */
51 static inline bool compaction_deferred(struct zone
*zone
, int order
)
53 unsigned long defer_limit
= 1UL << zone
->compact_defer_shift
;
55 if (order
< zone
->compact_order_failed
)
58 /* Avoid possible overflow */
59 if (++zone
->compact_considered
> defer_limit
)
60 zone
->compact_considered
= defer_limit
;
62 return zone
->compact_considered
< defer_limit
;
65 /* Returns true if restarting compaction after many failures */
66 static inline bool compaction_restarting(struct zone
*zone
, int order
)
68 if (order
< zone
->compact_order_failed
)
71 return zone
->compact_defer_shift
== COMPACT_MAX_DEFER_SHIFT
&&
72 zone
->compact_considered
>= 1UL << zone
->compact_defer_shift
;
76 static inline unsigned long try_to_compact_pages(struct zonelist
*zonelist
,
77 int order
, gfp_t gfp_mask
, nodemask_t
*nodemask
,
78 bool sync
, bool *contended
)
80 return COMPACT_CONTINUE
;
83 static inline void compact_pgdat(pg_data_t
*pgdat
, int order
)
87 static inline void reset_isolation_suitable(pg_data_t
*pgdat
)
91 static inline unsigned long compaction_suitable(struct zone
*zone
, int order
)
93 return COMPACT_SKIPPED
;
96 static inline void defer_compaction(struct zone
*zone
, int order
)
100 static inline bool compaction_deferred(struct zone
*zone
, int order
)
105 #endif /* CONFIG_COMPACTION */
107 #if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
108 extern int compaction_register_node(struct node
*node
);
109 extern void compaction_unregister_node(struct node
*node
);
113 static inline int compaction_register_node(struct node
*node
)
118 static inline void compaction_unregister_node(struct node
*node
)
121 #endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */
123 #endif /* _LINUX_COMPACTION_H */