1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_COMPACTION_H
3 #define _LINUX_COMPACTION_H
4
5 /*
6 * Determines how hard direct compaction should try to succeed.
7 * Lower value means higher priority, analogically to reclaim priority.
8 */
9 enum compact_priority {
10 COMPACT_PRIO_SYNC_FULL,
11 MIN_COMPACT_PRIORITY = COMPACT_PRIO_SYNC_FULL,
12 COMPACT_PRIO_SYNC_LIGHT,
13 MIN_COMPACT_COSTLY_PRIORITY = COMPACT_PRIO_SYNC_LIGHT,
14 DEF_COMPACT_PRIORITY = COMPACT_PRIO_SYNC_LIGHT,
15 COMPACT_PRIO_ASYNC,
16 INIT_COMPACT_PRIORITY = COMPACT_PRIO_ASYNC
17 };
18
19 /* Return values for compact_zone() and try_to_compact_pages() */
20 /* When adding new states, please adjust include/trace/events/compaction.h */
21 enum compact_result {
22 /* For more detailed tracepoint output - internal to compaction */
23 COMPACT_NOT_SUITABLE_ZONE,
24 /*
25 * compaction didn't start as it was not possible or direct reclaim
26 * was more suitable
27 */
28 COMPACT_SKIPPED,
29 /* compaction didn't start as it was deferred due to past failures */
30 COMPACT_DEFERRED,
31
32 /* For more detailed tracepoint output - internal to compaction */
33 COMPACT_NO_SUITABLE_PAGE,
34 /* compaction should continue to another pageblock */
35 COMPACT_CONTINUE,
36
37 /*
38 * The full zone was compacted scanned but wasn't successful to compact
39 * suitable pages.
40 */
41 COMPACT_COMPLETE,
42 /*
43 * direct compaction has scanned part of the zone but wasn't successful
44 * to compact suitable pages.
45 */
46 COMPACT_PARTIAL_SKIPPED,
47
48 /* compaction terminated prematurely due to lock contentions */
49 COMPACT_CONTENDED,
50
51 /*
52 * direct compaction terminated after concluding that the allocation
53 * should now succeed
54 */
55 COMPACT_SUCCESS,
56 };
57
58 struct alloc_context; /* in mm/internal.h */
59
60 /*
61 * Number of free order-0 pages that should be available above given watermark
62 * to make sure compaction has reasonable chance of not running out of free
63 * pages that it needs to isolate as migration target during its work.
64 */
compact_gap(unsigned int order)65 static inline unsigned long compact_gap(unsigned int order)
66 {
67 /*
68 * Although all the isolations for migration are temporary, compaction
69 * free scanner may have up to 1 << order pages on its list and then
70 * try to split an (order - 1) free page. At that point, a gap of
71 * 1 << order might not be enough, so it's safer to require twice that
72 * amount. Note that the number of pages on the list is also
73 * effectively limited by COMPACT_CLUSTER_MAX, as that's the maximum
74 * that the migrate scanner can have isolated on migrate list, and free
75 * scanner is only invoked when the number of isolated free pages is
76 * lower than that. But it's not worth to complicate the formula here
77 * as a bigger gap for higher orders than strictly necessary can also
78 * improve chances of compaction success.
79 */
80 return 2UL << order;
81 }
82
current_is_kcompactd(void)83 static inline int current_is_kcompactd(void)
84 {
85 return current->flags & PF_KCOMPACTD;
86 }
87
88 #ifdef CONFIG_COMPACTION
89
90 extern unsigned int extfrag_for_order(struct zone *zone, unsigned int order);
91 extern int fragmentation_index(struct zone *zone, unsigned int order);
92 extern enum compact_result try_to_compact_pages(gfp_t gfp_mask,
93 unsigned int order, unsigned int alloc_flags,
94 const struct alloc_context *ac, enum compact_priority prio,
95 struct page **page);
96 extern void reset_isolation_suitable(pg_data_t *pgdat);
97 extern bool compaction_suitable(struct zone *zone, int order,
98 int highest_zoneidx);
99
100 extern void compaction_defer_reset(struct zone *zone, int order,
101 bool alloc_success);
102
103 bool compaction_zonelist_suitable(struct alloc_context *ac, int order,
104 int alloc_flags);
105
106 extern void __meminit kcompactd_run(int nid);
107 extern void __meminit kcompactd_stop(int nid);
108 extern void wakeup_kcompactd(pg_data_t *pgdat, int order, int highest_zoneidx);
109
110 #else
reset_isolation_suitable(pg_data_t * pgdat)111 static inline void reset_isolation_suitable(pg_data_t *pgdat)
112 {
113 }
114
compaction_suitable(struct zone * zone,int order,int highest_zoneidx)115 static inline bool compaction_suitable(struct zone *zone, int order,
116 int highest_zoneidx)
117 {
118 return false;
119 }
120
kcompactd_run(int nid)121 static inline void kcompactd_run(int nid)
122 {
123 }
kcompactd_stop(int nid)124 static inline void kcompactd_stop(int nid)
125 {
126 }
127
wakeup_kcompactd(pg_data_t * pgdat,int order,int highest_zoneidx)128 static inline void wakeup_kcompactd(pg_data_t *pgdat,
129 int order, int highest_zoneidx)
130 {
131 }
132
133 #endif /* CONFIG_COMPACTION */
134
135 struct node;
136 #if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
137 extern int compaction_register_node(struct node *node);
138 extern void compaction_unregister_node(struct node *node);
139
140 #else
141
compaction_register_node(struct node * node)142 static inline int compaction_register_node(struct node *node)
143 {
144 return 0;
145 }
146
compaction_unregister_node(struct node * node)147 static inline void compaction_unregister_node(struct node *node)
148 {
149 }
150 #endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */
151
152 #endif /* _LINUX_COMPACTION_H */
153