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 partially compacted a zone and there might be
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 compact_pgdat(pg_data_t
*pgdat
, int order
);
74 extern void reset_isolation_suitable(pg_data_t
*pgdat
);
75 extern enum compact_result
compaction_suitable(struct zone
*zone
, int order
,
76 unsigned int alloc_flags
, int classzone_idx
);
78 extern void defer_compaction(struct zone
*zone
, int order
);
79 extern bool compaction_deferred(struct zone
*zone
, int order
);
80 extern void compaction_defer_reset(struct zone
*zone
, int order
,
82 extern bool compaction_restarting(struct zone
*zone
, int order
);
84 /* Compaction has made some progress and retrying makes sense */
85 static inline bool compaction_made_progress(enum compact_result result
)
88 * Even though this might sound confusing this in fact tells us
89 * that the compaction successfully isolated and migrated some
92 if (result
== COMPACT_PARTIAL
)
98 /* Compaction has failed and it doesn't make much sense to keep retrying. */
99 static inline bool compaction_failed(enum compact_result result
)
101 /* All zones were scanned completely and still not result. */
102 if (result
== COMPACT_COMPLETE
)
109 * Compaction has backed off for some reason. It might be throttling or
110 * lock contention. Retrying is still worthwhile.
112 static inline bool compaction_withdrawn(enum compact_result result
)
115 * Compaction backed off due to watermark checks for order-0
116 * so the regular reclaim has to try harder and reclaim something.
118 if (result
== COMPACT_SKIPPED
)
122 * If compaction is deferred for high-order allocations, it is
123 * because sync compaction recently failed. If this is the case
124 * and the caller requested a THP allocation, we do not want
125 * to heavily disrupt the system, so we fail the allocation
126 * instead of entering direct reclaim.
128 if (result
== COMPACT_DEFERRED
)
132 * If compaction in async mode encounters contention or blocks higher
133 * priority task we back off early rather than cause stalls.
135 if (result
== COMPACT_CONTENDED
)
139 * Page scanners have met but we haven't scanned full zones so this
140 * is a back off in fact.
142 if (result
== COMPACT_PARTIAL_SKIPPED
)
149 bool compaction_zonelist_suitable(struct alloc_context
*ac
, int order
,
152 extern int kcompactd_run(int nid
);
153 extern void kcompactd_stop(int nid
);
154 extern void wakeup_kcompactd(pg_data_t
*pgdat
, int order
, int classzone_idx
);
157 static inline void compact_pgdat(pg_data_t
*pgdat
, int order
)
161 static inline void reset_isolation_suitable(pg_data_t
*pgdat
)
165 static inline enum compact_result
compaction_suitable(struct zone
*zone
, int order
,
166 int alloc_flags
, int classzone_idx
)
168 return COMPACT_SKIPPED
;
171 static inline void defer_compaction(struct zone
*zone
, int order
)
175 static inline bool compaction_deferred(struct zone
*zone
, int order
)
180 static inline bool compaction_made_progress(enum compact_result result
)
185 static inline bool compaction_failed(enum compact_result result
)
190 static inline bool compaction_withdrawn(enum compact_result result
)
195 static inline int kcompactd_run(int nid
)
199 static inline void kcompactd_stop(int nid
)
203 static inline void wakeup_kcompactd(pg_data_t
*pgdat
, int order
, int classzone_idx
)
207 #endif /* CONFIG_COMPACTION */
209 #if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
211 extern int compaction_register_node(struct node
*node
);
212 extern void compaction_unregister_node(struct node
*node
);
216 static inline int compaction_register_node(struct node
*node
)
221 static inline void compaction_unregister_node(struct node
*node
)
224 #endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */
226 #endif /* _LINUX_COMPACTION_H */