1 #ifndef _LINUX_COMPACTION_H
2 #define _LINUX_COMPACTION_H
5 * Determines how hard direct compaction should try to succeed.
6 * Lower value means higher priority, analogically to reclaim priority.
8 enum compact_priority
{
9 COMPACT_PRIO_SYNC_LIGHT
,
10 MIN_COMPACT_PRIORITY
= COMPACT_PRIO_SYNC_LIGHT
,
11 DEF_COMPACT_PRIORITY
= COMPACT_PRIO_SYNC_LIGHT
,
13 INIT_COMPACT_PRIORITY
= COMPACT_PRIO_ASYNC
16 /* Return values for compact_zone() and try_to_compact_pages() */
17 /* When adding new states, please adjust include/trace/events/compaction.h */
19 /* For more detailed tracepoint output - internal to compaction */
20 COMPACT_NOT_SUITABLE_ZONE
,
22 * compaction didn't start as it was not possible or direct reclaim
26 /* compaction didn't start as it was deferred due to past failures */
29 /* compaction not active last round */
30 COMPACT_INACTIVE
= COMPACT_DEFERRED
,
32 /* For more detailed tracepoint output - internal to compaction */
33 COMPACT_NO_SUITABLE_PAGE
,
34 /* compaction should continue to another pageblock */
38 * The full zone was compacted scanned but wasn't successfull to compact
43 * direct compaction has scanned part of the zone but wasn't successfull
44 * to compact suitable pages.
46 COMPACT_PARTIAL_SKIPPED
,
48 /* compaction terminated prematurely due to lock contentions */
52 * direct compaction terminated after concluding that the allocation
58 struct alloc_context
; /* in mm/internal.h */
60 #ifdef CONFIG_COMPACTION
61 extern int sysctl_compact_memory
;
62 extern int sysctl_compaction_handler(struct ctl_table
*table
, int write
,
63 void __user
*buffer
, size_t *length
, loff_t
*ppos
);
64 extern int sysctl_extfrag_threshold
;
65 extern int sysctl_extfrag_handler(struct ctl_table
*table
, int write
,
66 void __user
*buffer
, size_t *length
, loff_t
*ppos
);
67 extern int sysctl_compact_unevictable_allowed
;
69 extern int fragmentation_index(struct zone
*zone
, unsigned int order
);
70 extern enum compact_result
try_to_compact_pages(gfp_t gfp_mask
,
71 unsigned int order
, unsigned int alloc_flags
,
72 const struct alloc_context
*ac
, enum compact_priority prio
);
73 extern void reset_isolation_suitable(pg_data_t
*pgdat
);
74 extern enum compact_result
compaction_suitable(struct zone
*zone
, int order
,
75 unsigned int alloc_flags
, int classzone_idx
);
77 extern void defer_compaction(struct zone
*zone
, int order
);
78 extern bool compaction_deferred(struct zone
*zone
, int order
);
79 extern void compaction_defer_reset(struct zone
*zone
, int order
,
81 extern bool compaction_restarting(struct zone
*zone
, int order
);
83 /* Compaction has made some progress and retrying makes sense */
84 static inline bool compaction_made_progress(enum compact_result result
)
87 * Even though this might sound confusing this in fact tells us
88 * that the compaction successfully isolated and migrated some
91 if (result
== COMPACT_SUCCESS
)
97 /* Compaction has failed and it doesn't make much sense to keep retrying. */
98 static inline bool compaction_failed(enum compact_result result
)
100 /* All zones were scanned completely and still not result. */
101 if (result
== COMPACT_COMPLETE
)
108 * Compaction has backed off for some reason. It might be throttling or
109 * lock contention. Retrying is still worthwhile.
111 static inline bool compaction_withdrawn(enum compact_result result
)
114 * Compaction backed off due to watermark checks for order-0
115 * so the regular reclaim has to try harder and reclaim something.
117 if (result
== COMPACT_SKIPPED
)
121 * If compaction is deferred for high-order allocations, it is
122 * because sync compaction recently failed. If this is the case
123 * and the caller requested a THP allocation, we do not want
124 * to heavily disrupt the system, so we fail the allocation
125 * instead of entering direct reclaim.
127 if (result
== COMPACT_DEFERRED
)
131 * If compaction in async mode encounters contention or blocks higher
132 * priority task we back off early rather than cause stalls.
134 if (result
== COMPACT_CONTENDED
)
138 * Page scanners have met but we haven't scanned full zones so this
139 * is a back off in fact.
141 if (result
== COMPACT_PARTIAL_SKIPPED
)
148 bool compaction_zonelist_suitable(struct alloc_context
*ac
, int order
,
151 extern int kcompactd_run(int nid
);
152 extern void kcompactd_stop(int nid
);
153 extern void wakeup_kcompactd(pg_data_t
*pgdat
, int order
, int classzone_idx
);
156 static inline void reset_isolation_suitable(pg_data_t
*pgdat
)
160 static inline enum compact_result
compaction_suitable(struct zone
*zone
, int order
,
161 int alloc_flags
, int classzone_idx
)
163 return COMPACT_SKIPPED
;
166 static inline void defer_compaction(struct zone
*zone
, int order
)
170 static inline bool compaction_deferred(struct zone
*zone
, int order
)
175 static inline bool compaction_made_progress(enum compact_result result
)
180 static inline bool compaction_failed(enum compact_result result
)
185 static inline bool compaction_withdrawn(enum compact_result result
)
190 static inline int kcompactd_run(int nid
)
194 static inline void kcompactd_stop(int nid
)
198 static inline void wakeup_kcompactd(pg_data_t
*pgdat
, int order
, int classzone_idx
)
202 #endif /* CONFIG_COMPACTION */
204 #if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
206 extern int compaction_register_node(struct node
*node
);
207 extern void compaction_unregister_node(struct node
*node
);
211 static inline int compaction_register_node(struct node
*node
)
216 static inline void compaction_unregister_node(struct node
*node
)
219 #endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */
221 #endif /* _LINUX_COMPACTION_H */