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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
748446bb MG |
2 | #ifndef _LINUX_COMPACTION_H |
3 | #define _LINUX_COMPACTION_H | |
4 | ||
a5508cd8 VB |
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 { | |
a8e025e5 VB |
10 | COMPACT_PRIO_SYNC_FULL, |
11 | MIN_COMPACT_PRIORITY = COMPACT_PRIO_SYNC_FULL, | |
a5508cd8 | 12 | COMPACT_PRIO_SYNC_LIGHT, |
c2033b00 | 13 | MIN_COMPACT_COSTLY_PRIORITY = COMPACT_PRIO_SYNC_LIGHT, |
a5508cd8 VB |
14 | DEF_COMPACT_PRIORITY = COMPACT_PRIO_SYNC_LIGHT, |
15 | COMPACT_PRIO_ASYNC, | |
16 | INIT_COMPACT_PRIORITY = COMPACT_PRIO_ASYNC | |
17 | }; | |
18 | ||
56de7263 | 19 | /* Return values for compact_zone() and try_to_compact_pages() */ |
fa6c7b46 | 20 | /* When adding new states, please adjust include/trace/events/compaction.h */ |
ea7ab982 | 21 | enum compact_result { |
4f9a358c MH |
22 | /* For more detailed tracepoint output - internal to compaction */ |
23 | COMPACT_NOT_SUITABLE_ZONE, | |
ea7ab982 MH |
24 | /* |
25 | * compaction didn't start as it was not possible or direct reclaim | |
26 | * was more suitable | |
27 | */ | |
28 | COMPACT_SKIPPED, | |
1d4746d3 MH |
29 | /* compaction didn't start as it was deferred due to past failures */ |
30 | COMPACT_DEFERRED, | |
4f9a358c | 31 | |
1d4746d3 MH |
32 | /* compaction not active last round */ |
33 | COMPACT_INACTIVE = COMPACT_DEFERRED, | |
34 | ||
4f9a358c MH |
35 | /* For more detailed tracepoint output - internal to compaction */ |
36 | COMPACT_NO_SUITABLE_PAGE, | |
ea7ab982 MH |
37 | /* compaction should continue to another pageblock */ |
38 | COMPACT_CONTINUE, | |
4f9a358c | 39 | |
ea7ab982 | 40 | /* |
4f9a358c MH |
41 | * The full zone was compacted scanned but wasn't successfull to compact |
42 | * suitable pages. | |
ea7ab982 | 43 | */ |
4f9a358c | 44 | COMPACT_COMPLETE, |
c8f7de0b MH |
45 | /* |
46 | * direct compaction has scanned part of the zone but wasn't successfull | |
47 | * to compact suitable pages. | |
48 | */ | |
49 | COMPACT_PARTIAL_SKIPPED, | |
4f9a358c MH |
50 | |
51 | /* compaction terminated prematurely due to lock contentions */ | |
52 | COMPACT_CONTENDED, | |
53 | ||
c8f7de0b | 54 | /* |
cf378319 VB |
55 | * direct compaction terminated after concluding that the allocation |
56 | * should now succeed | |
c8f7de0b | 57 | */ |
cf378319 | 58 | COMPACT_SUCCESS, |
ea7ab982 | 59 | }; |
748446bb | 60 | |
1a6d53a1 VB |
61 | struct alloc_context; /* in mm/internal.h */ |
62 | ||
9861a62c VB |
63 | /* |
64 | * Number of free order-0 pages that should be available above given watermark | |
65 | * to make sure compaction has reasonable chance of not running out of free | |
66 | * pages that it needs to isolate as migration target during its work. | |
67 | */ | |
68 | static inline unsigned long compact_gap(unsigned int order) | |
69 | { | |
70 | /* | |
71 | * Although all the isolations for migration are temporary, compaction | |
72 | * free scanner may have up to 1 << order pages on its list and then | |
73 | * try to split an (order - 1) free page. At that point, a gap of | |
74 | * 1 << order might not be enough, so it's safer to require twice that | |
75 | * amount. Note that the number of pages on the list is also | |
76 | * effectively limited by COMPACT_CLUSTER_MAX, as that's the maximum | |
77 | * that the migrate scanner can have isolated on migrate list, and free | |
78 | * scanner is only invoked when the number of isolated free pages is | |
79 | * lower than that. But it's not worth to complicate the formula here | |
80 | * as a bigger gap for higher orders than strictly necessary can also | |
81 | * improve chances of compaction success. | |
82 | */ | |
83 | return 2UL << order; | |
84 | } | |
85 | ||
76ab0f53 MG |
86 | #ifdef CONFIG_COMPACTION |
87 | extern int sysctl_compact_memory; | |
88 | extern int sysctl_compaction_handler(struct ctl_table *table, int write, | |
89 | void __user *buffer, size_t *length, loff_t *ppos); | |
5e771905 | 90 | extern int sysctl_extfrag_threshold; |
5bbe3547 | 91 | extern int sysctl_compact_unevictable_allowed; |
56de7263 MG |
92 | |
93 | extern int fragmentation_index(struct zone *zone, unsigned int order); | |
ea7ab982 | 94 | extern enum compact_result try_to_compact_pages(gfp_t gfp_mask, |
c3486f53 | 95 | unsigned int order, unsigned int alloc_flags, |
5e1f0f09 MG |
96 | const struct alloc_context *ac, enum compact_priority prio, |
97 | struct page **page); | |
62997027 | 98 | extern void reset_isolation_suitable(pg_data_t *pgdat); |
ea7ab982 | 99 | extern enum compact_result compaction_suitable(struct zone *zone, int order, |
c603844b | 100 | unsigned int alloc_flags, int classzone_idx); |
4f92e258 | 101 | |
24e2716f JK |
102 | extern void defer_compaction(struct zone *zone, int order); |
103 | extern bool compaction_deferred(struct zone *zone, int order); | |
104 | extern void compaction_defer_reset(struct zone *zone, int order, | |
105 | bool alloc_success); | |
106 | extern bool compaction_restarting(struct zone *zone, int order); | |
62997027 | 107 | |
cab1802b MH |
108 | /* Compaction has made some progress and retrying makes sense */ |
109 | static inline bool compaction_made_progress(enum compact_result result) | |
110 | { | |
111 | /* | |
112 | * Even though this might sound confusing this in fact tells us | |
113 | * that the compaction successfully isolated and migrated some | |
114 | * pageblocks. | |
115 | */ | |
cf378319 | 116 | if (result == COMPACT_SUCCESS) |
cab1802b MH |
117 | return true; |
118 | ||
119 | return false; | |
120 | } | |
121 | ||
122 | /* Compaction has failed and it doesn't make much sense to keep retrying. */ | |
123 | static inline bool compaction_failed(enum compact_result result) | |
124 | { | |
125 | /* All zones were scanned completely and still not result. */ | |
126 | if (result == COMPACT_COMPLETE) | |
127 | return true; | |
128 | ||
129 | return false; | |
130 | } | |
131 | ||
132 | /* | |
133 | * Compaction has backed off for some reason. It might be throttling or | |
134 | * lock contention. Retrying is still worthwhile. | |
135 | */ | |
136 | static inline bool compaction_withdrawn(enum compact_result result) | |
137 | { | |
138 | /* | |
139 | * Compaction backed off due to watermark checks for order-0 | |
140 | * so the regular reclaim has to try harder and reclaim something. | |
141 | */ | |
142 | if (result == COMPACT_SKIPPED) | |
143 | return true; | |
144 | ||
145 | /* | |
146 | * If compaction is deferred for high-order allocations, it is | |
147 | * because sync compaction recently failed. If this is the case | |
148 | * and the caller requested a THP allocation, we do not want | |
149 | * to heavily disrupt the system, so we fail the allocation | |
150 | * instead of entering direct reclaim. | |
151 | */ | |
152 | if (result == COMPACT_DEFERRED) | |
153 | return true; | |
154 | ||
155 | /* | |
156 | * If compaction in async mode encounters contention or blocks higher | |
157 | * priority task we back off early rather than cause stalls. | |
158 | */ | |
159 | if (result == COMPACT_CONTENDED) | |
160 | return true; | |
161 | ||
162 | /* | |
163 | * Page scanners have met but we haven't scanned full zones so this | |
164 | * is a back off in fact. | |
165 | */ | |
166 | if (result == COMPACT_PARTIAL_SKIPPED) | |
167 | return true; | |
168 | ||
169 | return false; | |
170 | } | |
171 | ||
86a294a8 MH |
172 | |
173 | bool compaction_zonelist_suitable(struct alloc_context *ac, int order, | |
174 | int alloc_flags); | |
175 | ||
698b1b30 VB |
176 | extern int kcompactd_run(int nid); |
177 | extern void kcompactd_stop(int nid); | |
178 | extern void wakeup_kcompactd(pg_data_t *pgdat, int order, int classzone_idx); | |
179 | ||
56de7263 | 180 | #else |
62997027 MG |
181 | static inline void reset_isolation_suitable(pg_data_t *pgdat) |
182 | { | |
183 | } | |
184 | ||
ea7ab982 | 185 | static inline enum compact_result compaction_suitable(struct zone *zone, int order, |
ebff3980 | 186 | int alloc_flags, int classzone_idx) |
3e7d3449 MG |
187 | { |
188 | return COMPACT_SKIPPED; | |
189 | } | |
190 | ||
aff62249 | 191 | static inline void defer_compaction(struct zone *zone, int order) |
4f92e258 MG |
192 | { |
193 | } | |
194 | ||
aff62249 | 195 | static inline bool compaction_deferred(struct zone *zone, int order) |
4f92e258 | 196 | { |
c59e2610 | 197 | return true; |
4f92e258 MG |
198 | } |
199 | ||
cab1802b MH |
200 | static inline bool compaction_made_progress(enum compact_result result) |
201 | { | |
202 | return false; | |
203 | } | |
204 | ||
205 | static inline bool compaction_failed(enum compact_result result) | |
206 | { | |
207 | return false; | |
208 | } | |
209 | ||
210 | static inline bool compaction_withdrawn(enum compact_result result) | |
211 | { | |
212 | return true; | |
213 | } | |
214 | ||
698b1b30 VB |
215 | static inline int kcompactd_run(int nid) |
216 | { | |
217 | return 0; | |
218 | } | |
219 | static inline void kcompactd_stop(int nid) | |
220 | { | |
221 | } | |
222 | ||
223 | static inline void wakeup_kcompactd(pg_data_t *pgdat, int order, int classzone_idx) | |
224 | { | |
225 | } | |
226 | ||
76ab0f53 MG |
227 | #endif /* CONFIG_COMPACTION */ |
228 | ||
bda807d4 | 229 | struct node; |
ace451eb | 230 | #if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA) |
ed4a6d7f MG |
231 | extern int compaction_register_node(struct node *node); |
232 | extern void compaction_unregister_node(struct node *node); | |
233 | ||
234 | #else | |
235 | ||
236 | static inline int compaction_register_node(struct node *node) | |
237 | { | |
238 | return 0; | |
239 | } | |
240 | ||
241 | static inline void compaction_unregister_node(struct node *node) | |
242 | { | |
243 | } | |
244 | #endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */ | |
245 | ||
748446bb | 246 | #endif /* _LINUX_COMPACTION_H */ |