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 */