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 | */ |
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 | |
83 | #ifdef CONFIG_COMPACTION |
84 | |
85 | extern unsigned int extfrag_for_order(struct zone *zone, unsigned int order); |
86 | extern int fragmentation_index(struct zone *zone, unsigned int order); |
87 | extern enum compact_result try_to_compact_pages(gfp_t gfp_mask, |
88 | unsigned int order, unsigned int alloc_flags, |
89 | const struct alloc_context *ac, enum compact_priority prio, |
90 | struct page **page); |
91 | extern void reset_isolation_suitable(pg_data_t *pgdat); |
92 | extern bool compaction_suitable(struct zone *zone, int order, |
93 | int highest_zoneidx); |
94 | |
95 | extern void compaction_defer_reset(struct zone *zone, int order, |
96 | bool alloc_success); |
97 | |
98 | bool compaction_zonelist_suitable(struct alloc_context *ac, int order, |
99 | int alloc_flags); |
100 | |
101 | extern void __meminit kcompactd_run(int nid); |
102 | extern void __meminit kcompactd_stop(int nid); |
103 | extern void wakeup_kcompactd(pg_data_t *pgdat, int order, int highest_zoneidx); |
104 | |
105 | #else |
106 | static inline void reset_isolation_suitable(pg_data_t *pgdat) |
107 | { |
108 | } |
109 | |
110 | static inline bool compaction_suitable(struct zone *zone, int order, |
111 | int highest_zoneidx) |
112 | { |
113 | return false; |
114 | } |
115 | |
116 | static inline void kcompactd_run(int nid) |
117 | { |
118 | } |
119 | static inline void kcompactd_stop(int nid) |
120 | { |
121 | } |
122 | |
123 | static inline void wakeup_kcompactd(pg_data_t *pgdat, |
124 | int order, int highest_zoneidx) |
125 | { |
126 | } |
127 | |
128 | #endif /* CONFIG_COMPACTION */ |
129 | |
130 | struct node; |
131 | #if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA) |
132 | extern int compaction_register_node(struct node *node); |
133 | extern void compaction_unregister_node(struct node *node); |
134 | |
135 | #else |
136 | |
137 | static inline int compaction_register_node(struct node *node) |
138 | { |
139 | return 0; |
140 | } |
141 | |
142 | static inline void compaction_unregister_node(struct node *node) |
143 | { |
144 | } |
145 | #endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */ |
146 | |
147 | #endif /* _LINUX_COMPACTION_H */ |
148 | |