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
,
26 extern unsigned long compaction_suitable(struct zone
*zone
, int order
);
28 /* Do not skip compaction more than 64 times */
29 #define COMPACT_MAX_DEFER_SHIFT 6
32 * Compaction is deferred when compaction fails to result in a page
33 * allocation success. 1 << compact_defer_limit compactions are skipped up
34 * to a limit of 1 << COMPACT_MAX_DEFER_SHIFT
36 static inline void defer_compaction(struct zone
*zone
)
38 zone
->compact_considered
= 0;
39 zone
->compact_defer_shift
++;
41 if (zone
->compact_defer_shift
> COMPACT_MAX_DEFER_SHIFT
)
42 zone
->compact_defer_shift
= COMPACT_MAX_DEFER_SHIFT
;
45 /* Returns true if compaction should be skipped this time */
46 static inline bool compaction_deferred(struct zone
*zone
)
48 unsigned long defer_limit
= 1UL << zone
->compact_defer_shift
;
50 /* Avoid possible overflow */
51 if (++zone
->compact_considered
> defer_limit
)
52 zone
->compact_considered
= defer_limit
;
54 return zone
->compact_considered
< (1UL << zone
->compact_defer_shift
);
58 static inline unsigned long try_to_compact_pages(struct zonelist
*zonelist
,
59 int order
, gfp_t gfp_mask
, nodemask_t
*nodemask
,
62 return COMPACT_CONTINUE
;
65 static inline unsigned long compaction_suitable(struct zone
*zone
, int order
)
67 return COMPACT_SKIPPED
;
70 static inline void defer_compaction(struct zone
*zone
)
74 static inline bool compaction_deferred(struct zone
*zone
)
79 #endif /* CONFIG_COMPACTION */
81 #if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
82 extern int compaction_register_node(struct node
*node
);
83 extern void compaction_unregister_node(struct node
*node
);
87 static inline int compaction_register_node(struct node
*node
)
92 static inline void compaction_unregister_node(struct node
*node
)
95 #endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */
97 #endif /* _LINUX_COMPACTION_H */
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