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 */ 9enum 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 */ 21enum 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 58struct 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 */ 65static 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 85extern unsigned int extfrag_for_order(struct zone *zone, unsigned int order); 86extern int fragmentation_index(struct zone *zone, unsigned int order); 87extern 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); 91extern void reset_isolation_suitable(pg_data_t *pgdat); 92extern bool compaction_suitable(struct zone *zone, int order, 93 int highest_zoneidx); 94 95extern void compaction_defer_reset(struct zone *zone, int order, 96 bool alloc_success); 97 98bool compaction_zonelist_suitable(struct alloc_context *ac, int order, 99 int alloc_flags); 100 101extern void __meminit kcompactd_run(int nid); 102extern void __meminit kcompactd_stop(int nid); 103extern void wakeup_kcompactd(pg_data_t *pgdat, int order, int highest_zoneidx); 104 105#else 106static inline void reset_isolation_suitable(pg_data_t *pgdat) 107{ 108} 109 110static inline bool compaction_suitable(struct zone *zone, int order, 111 int highest_zoneidx) 112{ 113 return false; 114} 115 116static inline void kcompactd_run(int nid) 117{ 118} 119static inline void kcompactd_stop(int nid) 120{ 121} 122 123static inline void wakeup_kcompactd(pg_data_t *pgdat, 124 int order, int highest_zoneidx) 125{ 126} 127 128#endif /* CONFIG_COMPACTION */ 129 130struct node; 131#if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA) 132extern int compaction_register_node(struct node *node); 133extern void compaction_unregister_node(struct node *node); 134 135#else 136 137static inline int compaction_register_node(struct node *node) 138{ 139 return 0; 140} 141 142static 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