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
, struct page
**page
);
26 extern int compact_pgdat(pg_data_t
*pgdat
, int order
);
27 extern unsigned long compaction_suitable(struct zone
*zone
, int order
);
29 /* Do not skip compaction more than 64 times */
30 #define COMPACT_MAX_DEFER_SHIFT 6
33 * Compaction is deferred when compaction fails to result in a page
34 * allocation success. 1 << compact_defer_limit compactions are skipped up
35 * to a limit of 1 << COMPACT_MAX_DEFER_SHIFT
37 static inline void defer_compaction(struct zone
*zone
, int order
)
39 zone
->compact_considered
= 0;
40 zone
->compact_defer_shift
++;
42 if (order
< zone
->compact_order_failed
)
43 zone
->compact_order_failed
= order
;
45 if (zone
->compact_defer_shift
> COMPACT_MAX_DEFER_SHIFT
)
46 zone
->compact_defer_shift
= COMPACT_MAX_DEFER_SHIFT
;
49 /* Returns true if compaction should be skipped this time */
50 static inline bool compaction_deferred(struct zone
*zone
, int order
)
52 unsigned long defer_limit
= 1UL << zone
->compact_defer_shift
;
54 if (order
< zone
->compact_order_failed
)
57 /* Avoid possible overflow */
58 if (++zone
->compact_considered
> defer_limit
)
59 zone
->compact_considered
= defer_limit
;
61 return zone
->compact_considered
< defer_limit
;
65 static inline unsigned long try_to_compact_pages(struct zonelist
*zonelist
,
66 int order
, gfp_t gfp_mask
, nodemask_t
*nodemask
,
67 bool sync
, bool *contended
, struct page
**page
)
69 return COMPACT_CONTINUE
;
72 static inline int compact_pgdat(pg_data_t
*pgdat
, int order
)
74 return COMPACT_CONTINUE
;
77 static inline unsigned long compaction_suitable(struct zone
*zone
, int order
)
79 return COMPACT_SKIPPED
;
82 static inline void defer_compaction(struct zone
*zone
, int order
)
86 static inline bool compaction_deferred(struct zone
*zone
, int order
)
91 #endif /* CONFIG_COMPACTION */
93 #if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
94 extern int compaction_register_node(struct node
*node
);
95 extern void compaction_unregister_node(struct node
*node
);
99 static inline int compaction_register_node(struct node
*node
)
104 static inline void compaction_unregister_node(struct node
*node
)
107 #endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */
109 #endif /* _LINUX_COMPACTION_H */
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