1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_COMPACTION_H 3 #define _LINUX_COMPACTION_H 4 5 #include <linux/swap.h> 6 7 /* 8 * Determines how hard direct compaction should try to succeed. 9 * Lower value means higher priority, analogically to reclaim priority. 10 */ 11 enum compact_priority { 12 COMPACT_PRIO_SYNC_FULL, 13 MIN_COMPACT_PRIORITY = COMPACT_PRIO_SYNC_FULL, 14 COMPACT_PRIO_SYNC_LIGHT, 15 MIN_COMPACT_COSTLY_PRIORITY = COMPACT_PRIO_SYNC_LIGHT, 16 DEF_COMPACT_PRIORITY = COMPACT_PRIO_SYNC_LIGHT, 17 COMPACT_PRIO_ASYNC, 18 INIT_COMPACT_PRIORITY = COMPACT_PRIO_ASYNC 19 }; 20 21 /* Return values for compact_zone() and try_to_compact_pages() */ 22 /* When adding new states, please adjust include/trace/events/compaction.h */ 23 enum compact_result { 24 /* For more detailed tracepoint output - internal to compaction */ 25 COMPACT_NOT_SUITABLE_ZONE, 26 /* 27 * compaction didn't start as it was not possible or direct reclaim 28 * was more suitable 29 */ 30 COMPACT_SKIPPED, 31 /* compaction didn't start as it was deferred due to past failures */ 32 COMPACT_DEFERRED, 33 34 /* For more detailed tracepoint output - internal to compaction */ 35 COMPACT_NO_SUITABLE_PAGE, 36 /* compaction should continue to another pageblock */ 37 COMPACT_CONTINUE, 38 39 /* 40 * The full zone was compacted scanned but wasn't successful to compact 41 * suitable pages. 42 */ 43 COMPACT_COMPLETE, 44 /* 45 * direct compaction has scanned part of the zone but wasn't successful 46 * to compact suitable pages. 47 */ 48 COMPACT_PARTIAL_SKIPPED, 49 50 /* compaction terminated prematurely due to lock contentions */ 51 COMPACT_CONTENDED, 52 53 /* 54 * direct compaction terminated after concluding that the allocation 55 * should now succeed 56 */ 57 COMPACT_SUCCESS, 58 }; 59 60 struct alloc_context; /* in mm/internal.h */ 61 62 /* 63 * Number of free order-0 pages that should be available above given watermark 64 * to make sure compaction has reasonable chance of not running out of free 65 * pages that it needs to isolate as migration target during its work. 66 */ 67 static inline unsigned long compact_gap(unsigned int order) 68 { 69 /* 70 * Although all the isolations for migration are temporary, compaction 71 * free scanner may have up to 1 << order pages on its list and then 72 * try to split an (order - 1) free page. At that point, a gap of 73 * 1 << order might not be enough, so it's safer to require twice that 74 * amount. Note that the number of pages on the list is also 75 * effectively limited by COMPACT_CLUSTER_MAX, as that's the maximum 76 * that the migrate scanner can have isolated on migrate list, and free 77 * scanner is only invoked when the number of isolated free pages is 78 * lower than that. 79 */ 80 return min(2UL << order, COMPACT_CLUSTER_MAX); 81 } 82 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 unsigned long watermark, 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, gfp_t gfp_mask); 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 111 static inline void reset_isolation_suitable(pg_data_t *pgdat) 112 { 113 } 114 115 static inline bool compaction_suitable(struct zone *zone, int order, 116 unsigned long watermark, 117 int highest_zoneidx) 118 { 119 return false; 120 } 121 122 static inline void kcompactd_run(int nid) 123 { 124 } 125 static inline void kcompactd_stop(int nid) 126 { 127 } 128 129 static inline void wakeup_kcompactd(pg_data_t *pgdat, 130 int order, int highest_zoneidx) 131 { 132 } 133 134 #endif /* CONFIG_COMPACTION */ 135 136 struct node; 137 #if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA) 138 extern int compaction_register_node(struct node *node); 139 extern void compaction_unregister_node(struct node *node); 140 141 #else 142 143 static inline int compaction_register_node(struct node *node) 144 { 145 return 0; 146 } 147 148 static inline void compaction_unregister_node(struct node *node) 149 { 150 } 151 #endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */ 152 153 #endif /* _LINUX_COMPACTION_H */ 154