1 #ifndef _LINUX_COMPACTION_H
2 #define _LINUX_COMPACTION_H
4 #include <linux/node.h>
6 /* Return values for compact_zone() and try_to_compact_pages() */
7 /* compaction didn't start as it was not possible or direct reclaim was more suitable */
8 #define COMPACT_SKIPPED 0
9 /* compaction should continue to another pageblock */
10 #define COMPACT_CONTINUE 1
11 /* direct compaction partially compacted a zone and there are suitable pages */
12 #define COMPACT_PARTIAL 2
13 /* The full zone was compacted */
14 #define COMPACT_COMPLETE 3
17 * compaction supports three modes
19 * COMPACT_ASYNC_MOVABLE uses asynchronous migration and only scans
20 * MIGRATE_MOVABLE pageblocks as migration sources and targets.
21 * COMPACT_ASYNC_UNMOVABLE uses asynchronous migration and only scans
22 * MIGRATE_MOVABLE pageblocks as migration sources.
23 * MIGRATE_UNMOVABLE pageblocks are scanned as potential migration
24 * targets and convers them to MIGRATE_MOVABLE if possible
25 * COMPACT_SYNC uses synchronous migration and scans all pageblocks
28 COMPACT_ASYNC_MOVABLE
,
29 COMPACT_ASYNC_UNMOVABLE
,
33 #ifdef CONFIG_COMPACTION
34 extern int sysctl_compact_memory
;
35 extern int sysctl_compaction_handler(struct ctl_table
*table
, int write
,
36 void __user
*buffer
, size_t *length
, loff_t
*ppos
);
37 extern int sysctl_extfrag_threshold
;
38 extern int sysctl_extfrag_handler(struct ctl_table
*table
, int write
,
39 void __user
*buffer
, size_t *length
, loff_t
*ppos
);
41 extern int fragmentation_index(struct zone
*zone
, unsigned int order
);
42 extern unsigned long try_to_compact_pages(struct zonelist
*zonelist
,
43 int order
, gfp_t gfp_mask
, nodemask_t
*mask
,
45 extern int compact_pgdat(pg_data_t
*pgdat
, int order
);
46 extern unsigned long compaction_suitable(struct zone
*zone
, int order
);
48 /* Do not skip compaction more than 64 times */
49 #define COMPACT_MAX_DEFER_SHIFT 6
52 * Compaction is deferred when compaction fails to result in a page
53 * allocation success. 1 << compact_defer_limit compactions are skipped up
54 * to a limit of 1 << COMPACT_MAX_DEFER_SHIFT
56 static inline void defer_compaction(struct zone
*zone
, int order
)
58 zone
->compact_considered
= 0;
59 zone
->compact_defer_shift
++;
61 if (order
< zone
->compact_order_failed
)
62 zone
->compact_order_failed
= order
;
64 if (zone
->compact_defer_shift
> COMPACT_MAX_DEFER_SHIFT
)
65 zone
->compact_defer_shift
= COMPACT_MAX_DEFER_SHIFT
;
68 /* Returns true if compaction should be skipped this time */
69 static inline bool compaction_deferred(struct zone
*zone
, int order
)
71 unsigned long defer_limit
= 1UL << zone
->compact_defer_shift
;
73 if (order
< zone
->compact_order_failed
)
76 /* Avoid possible overflow */
77 if (++zone
->compact_considered
> defer_limit
)
78 zone
->compact_considered
= defer_limit
;
80 return zone
->compact_considered
< (1UL << zone
->compact_defer_shift
);
84 static inline unsigned long try_to_compact_pages(struct zonelist
*zonelist
,
85 int order
, gfp_t gfp_mask
, nodemask_t
*nodemask
,
88 return COMPACT_CONTINUE
;
91 static inline int compact_pgdat(pg_data_t
*pgdat
, int order
)
93 return COMPACT_CONTINUE
;
96 static inline unsigned long compaction_suitable(struct zone
*zone
, int order
)
98 return COMPACT_SKIPPED
;
101 static inline void defer_compaction(struct zone
*zone
, int order
)
105 static inline bool compaction_deferred(struct zone
*zone
, int order
)
110 #endif /* CONFIG_COMPACTION */
112 #if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
113 extern int compaction_register_node(struct node
*node
);
114 extern void compaction_unregister_node(struct node
*node
);
118 static inline int compaction_register_node(struct node
*node
)
123 static inline void compaction_unregister_node(struct node
*node
)
126 #endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */
128 #endif /* _LINUX_COMPACTION_H */
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