1 #ifndef _LINUX_COMPACTION_H
2 #define _LINUX_COMPACTION_H
4 /* Return values for compact_zone() and try_to_compact_pages() */
5 /* When adding new states, please adjust include/trace/events/compaction.h */
7 /* For more detailed tracepoint output - internal to compaction */
8 COMPACT_NOT_SUITABLE_ZONE,
10 * compaction didn't start as it was not possible or direct reclaim
14 /* compaction didn't start as it was deferred due to past failures */
17 /* compaction not active last round */
18 COMPACT_INACTIVE = COMPACT_DEFERRED,
20 /* For more detailed tracepoint output - internal to compaction */
21 COMPACT_NO_SUITABLE_PAGE,
22 /* compaction should continue to another pageblock */
26 * The full zone was compacted scanned but wasn't successfull to compact
31 * direct compaction has scanned part of the zone but wasn't successfull
32 * to compact suitable pages.
34 COMPACT_PARTIAL_SKIPPED,
36 /* compaction terminated prematurely due to lock contentions */
40 * direct compaction partially compacted a zone and there might be
46 /* Used to signal whether compaction detected need_sched() or lock contention */
47 /* No contention detected */
48 #define COMPACT_CONTENDED_NONE 0
49 /* Either need_sched() was true or fatal signal pending */
50 #define COMPACT_CONTENDED_SCHED 1
51 /* Zone lock or lru_lock was contended in async compaction */
52 #define COMPACT_CONTENDED_LOCK 2
54 struct alloc_context; /* in mm/internal.h */
56 #ifdef CONFIG_COMPACTION
57 extern int sysctl_compact_memory;
58 extern int sysctl_compaction_handler(struct ctl_table *table, int write,
59 void __user *buffer, size_t *length, loff_t *ppos);
60 extern int sysctl_extfrag_threshold;
61 extern int sysctl_extfrag_handler(struct ctl_table *table, int write,
62 void __user *buffer, size_t *length, loff_t *ppos);
63 extern int sysctl_compact_unevictable_allowed;
65 extern int fragmentation_index(struct zone *zone, unsigned int order);
66 extern enum compact_result try_to_compact_pages(gfp_t gfp_mask,
68 unsigned int alloc_flags, const struct alloc_context *ac,
69 enum migrate_mode mode, int *contended);
70 extern void compact_pgdat(pg_data_t *pgdat, int order);
71 extern void reset_isolation_suitable(pg_data_t *pgdat);
72 extern enum compact_result compaction_suitable(struct zone *zone, int order,
73 unsigned int alloc_flags, int classzone_idx);
75 extern void defer_compaction(struct zone *zone, int order);
76 extern bool compaction_deferred(struct zone *zone, int order);
77 extern void compaction_defer_reset(struct zone *zone, int order,
79 extern bool compaction_restarting(struct zone *zone, int order);
81 /* Compaction has made some progress and retrying makes sense */
82 static inline bool compaction_made_progress(enum compact_result result)
85 * Even though this might sound confusing this in fact tells us
86 * that the compaction successfully isolated and migrated some
89 if (result == COMPACT_PARTIAL)
95 /* Compaction has failed and it doesn't make much sense to keep retrying. */
96 static inline bool compaction_failed(enum compact_result result)
98 /* All zones were scanned completely and still not result. */
99 if (result == COMPACT_COMPLETE)
106 * Compaction has backed off for some reason. It might be throttling or
107 * lock contention. Retrying is still worthwhile.
109 static inline bool compaction_withdrawn(enum compact_result result)
112 * Compaction backed off due to watermark checks for order-0
113 * so the regular reclaim has to try harder and reclaim something.
115 if (result == COMPACT_SKIPPED)
119 * If compaction is deferred for high-order allocations, it is
120 * because sync compaction recently failed. If this is the case
121 * and the caller requested a THP allocation, we do not want
122 * to heavily disrupt the system, so we fail the allocation
123 * instead of entering direct reclaim.
125 if (result == COMPACT_DEFERRED)
129 * If compaction in async mode encounters contention or blocks higher
130 * priority task we back off early rather than cause stalls.
132 if (result == COMPACT_CONTENDED)
136 * Page scanners have met but we haven't scanned full zones so this
137 * is a back off in fact.
139 if (result == COMPACT_PARTIAL_SKIPPED)
146 bool compaction_zonelist_suitable(struct alloc_context *ac, int order,
149 extern int kcompactd_run(int nid);
150 extern void kcompactd_stop(int nid);
151 extern void wakeup_kcompactd(pg_data_t *pgdat, int order, int classzone_idx);
154 static inline enum compact_result try_to_compact_pages(gfp_t gfp_mask,
155 unsigned int order, int alloc_flags,
156 const struct alloc_context *ac,
157 enum migrate_mode mode, int *contended)
159 return COMPACT_CONTINUE;
162 static inline void compact_pgdat(pg_data_t *pgdat, int order)
166 static inline void reset_isolation_suitable(pg_data_t *pgdat)
170 static inline enum compact_result compaction_suitable(struct zone *zone, int order,
171 int alloc_flags, int classzone_idx)
173 return COMPACT_SKIPPED;
176 static inline void defer_compaction(struct zone *zone, int order)
180 static inline bool compaction_deferred(struct zone *zone, int order)
185 static inline bool compaction_made_progress(enum compact_result result)
190 static inline bool compaction_failed(enum compact_result result)
195 static inline bool compaction_withdrawn(enum compact_result result)
200 static inline int kcompactd_run(int nid)
204 static inline void kcompactd_stop(int nid)
208 static inline void wakeup_kcompactd(pg_data_t *pgdat, int order, int classzone_idx)
212 #endif /* CONFIG_COMPACTION */
214 #if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
215 extern int compaction_register_node(struct node *node);
216 extern void compaction_unregister_node(struct node *node);
220 static inline int compaction_register_node(struct node *node)
225 static inline void compaction_unregister_node(struct node *node)
228 #endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */
230 #endif /* _LINUX_COMPACTION_H */