| /* SPDX-License-Identifier: GPL-2.0 */ |
| #ifndef _LINUX_COMPACTION_H |
| #define _LINUX_COMPACTION_H |
| |
| /* |
| * Determines how hard direct compaction should try to succeed. |
| * Lower value means higher priority, analogically to reclaim priority. |
| */ |
| enum compact_priority { |
| COMPACT_PRIO_SYNC_FULL, |
| MIN_COMPACT_PRIORITY = COMPACT_PRIO_SYNC_FULL, |
| COMPACT_PRIO_SYNC_LIGHT, |
| MIN_COMPACT_COSTLY_PRIORITY = COMPACT_PRIO_SYNC_LIGHT, |
| DEF_COMPACT_PRIORITY = COMPACT_PRIO_SYNC_LIGHT, |
| COMPACT_PRIO_ASYNC, |
| INIT_COMPACT_PRIORITY = COMPACT_PRIO_ASYNC |
| }; |
| |
| /* Return values for compact_zone() and try_to_compact_pages() */ |
| /* When adding new states, please adjust include/trace/events/compaction.h */ |
| enum compact_result { |
| /* For more detailed tracepoint output - internal to compaction */ |
| COMPACT_NOT_SUITABLE_ZONE, |
| /* |
| * compaction didn't start as it was not possible or direct reclaim |
| * was more suitable |
| */ |
| COMPACT_SKIPPED, |
| /* compaction didn't start as it was deferred due to past failures */ |
| COMPACT_DEFERRED, |
| |
| /* For more detailed tracepoint output - internal to compaction */ |
| COMPACT_NO_SUITABLE_PAGE, |
| /* compaction should continue to another pageblock */ |
| COMPACT_CONTINUE, |
| |
| /* |
| * The full zone was compacted scanned but wasn't successfull to compact |
| * suitable pages. |
| */ |
| COMPACT_COMPLETE, |
| /* |
| * direct compaction has scanned part of the zone but wasn't successfull |
| * to compact suitable pages. |
| */ |
| COMPACT_PARTIAL_SKIPPED, |
| |
| /* compaction terminated prematurely due to lock contentions */ |
| COMPACT_CONTENDED, |
| |
| /* |
| * direct compaction terminated after concluding that the allocation |
| * should now succeed |
| */ |
| COMPACT_SUCCESS, |
| }; |
| |
| struct alloc_context; /* in mm/internal.h */ |
| |
| /* |
| * Number of free order-0 pages that should be available above given watermark |
| * to make sure compaction has reasonable chance of not running out of free |
| * pages that it needs to isolate as migration target during its work. |
| */ |
| static inline unsigned long compact_gap(unsigned int order) |
| { |
| /* |
| * Although all the isolations for migration are temporary, compaction |
| * free scanner may have up to 1 << order pages on its list and then |
| * try to split an (order - 1) free page. At that point, a gap of |
| * 1 << order might not be enough, so it's safer to require twice that |
| * amount. Note that the number of pages on the list is also |
| * effectively limited by COMPACT_CLUSTER_MAX, as that's the maximum |
| * that the migrate scanner can have isolated on migrate list, and free |
| * scanner is only invoked when the number of isolated free pages is |
| * lower than that. But it's not worth to complicate the formula here |
| * as a bigger gap for higher orders than strictly necessary can also |
| * improve chances of compaction success. |
| */ |
| return 2UL << order; |
| } |
| |
| #ifdef CONFIG_COMPACTION |
| extern int sysctl_compact_memory; |
| extern unsigned int sysctl_compaction_proactiveness; |
| extern int sysctl_compaction_handler(struct ctl_table *table, int write, |
| void *buffer, size_t *length, loff_t *ppos); |
| extern int sysctl_extfrag_threshold; |
| extern int sysctl_compact_unevictable_allowed; |
| |
| extern unsigned int extfrag_for_order(struct zone *zone, unsigned int order); |
| extern int fragmentation_index(struct zone *zone, unsigned int order); |
| extern enum compact_result try_to_compact_pages(gfp_t gfp_mask, |
| unsigned int order, unsigned int alloc_flags, |
| const struct alloc_context *ac, enum compact_priority prio, |
| struct page **page); |
| extern void reset_isolation_suitable(pg_data_t *pgdat); |
| extern enum compact_result compaction_suitable(struct zone *zone, int order, |
| unsigned int alloc_flags, int highest_zoneidx); |
| |
| extern void compaction_defer_reset(struct zone *zone, int order, |
| bool alloc_success); |
| |
| /* Compaction has made some progress and retrying makes sense */ |
| static inline bool compaction_made_progress(enum compact_result result) |
| { |
| /* |
| * Even though this might sound confusing this in fact tells us |
| * that the compaction successfully isolated and migrated some |
| * pageblocks. |
| */ |
| if (result == COMPACT_SUCCESS) |
| return true; |
| |
| return false; |
| } |
| |
| /* Compaction has failed and it doesn't make much sense to keep retrying. */ |
| static inline bool compaction_failed(enum compact_result result) |
| { |
| /* All zones were scanned completely and still not result. */ |
| if (result == COMPACT_COMPLETE) |
| return true; |
| |
| return false; |
| } |
| |
| /* Compaction needs reclaim to be performed first, so it can continue. */ |
| static inline bool compaction_needs_reclaim(enum compact_result result) |
| { |
| /* |
| * Compaction backed off due to watermark checks for order-0 |
| * so the regular reclaim has to try harder and reclaim something. |
| */ |
| if (result == COMPACT_SKIPPED) |
| return true; |
| |
| return false; |
| } |
| |
| /* |
| * Compaction has backed off for some reason after doing some work or none |
| * at all. It might be throttling or lock contention. Retrying might be still |
| * worthwhile, but with a higher priority if allowed. |
| */ |
| static inline bool compaction_withdrawn(enum compact_result result) |
| { |
| /* |
| * If compaction is deferred for high-order allocations, it is |
| * because sync compaction recently failed. If this is the case |
| * and the caller requested a THP allocation, we do not want |
| * to heavily disrupt the system, so we fail the allocation |
| * instead of entering direct reclaim. |
| */ |
| if (result == COMPACT_DEFERRED) |
| return true; |
| |
| /* |
| * If compaction in async mode encounters contention or blocks higher |
| * priority task we back off early rather than cause stalls. |
| */ |
| if (result == COMPACT_CONTENDED) |
| return true; |
| |
| /* |
| * Page scanners have met but we haven't scanned full zones so this |
| * is a back off in fact. |
| */ |
| if (result == COMPACT_PARTIAL_SKIPPED) |
| return true; |
| |
| return false; |
| } |
| |
| |
| bool compaction_zonelist_suitable(struct alloc_context *ac, int order, |
| int alloc_flags); |
| |
| extern int kcompactd_run(int nid); |
| extern void kcompactd_stop(int nid); |
| extern void wakeup_kcompactd(pg_data_t *pgdat, int order, int highest_zoneidx); |
| |
| #else |
| static inline void reset_isolation_suitable(pg_data_t *pgdat) |
| { |
| } |
| |
| static inline enum compact_result compaction_suitable(struct zone *zone, int order, |
| int alloc_flags, int highest_zoneidx) |
| { |
| return COMPACT_SKIPPED; |
| } |
| |
| static inline bool compaction_made_progress(enum compact_result result) |
| { |
| return false; |
| } |
| |
| static inline bool compaction_failed(enum compact_result result) |
| { |
| return false; |
| } |
| |
| static inline bool compaction_needs_reclaim(enum compact_result result) |
| { |
| return false; |
| } |
| |
| static inline bool compaction_withdrawn(enum compact_result result) |
| { |
| return true; |
| } |
| |
| static inline int kcompactd_run(int nid) |
| { |
| return 0; |
| } |
| static inline void kcompactd_stop(int nid) |
| { |
| } |
| |
| static inline void wakeup_kcompactd(pg_data_t *pgdat, |
| int order, int highest_zoneidx) |
| { |
| } |
| |
| #endif /* CONFIG_COMPACTION */ |
| |
| struct node; |
| #if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA) |
| extern int compaction_register_node(struct node *node); |
| extern void compaction_unregister_node(struct node *node); |
| |
| #else |
| |
| static inline int compaction_register_node(struct node *node) |
| { |
| return 0; |
| } |
| |
| static inline void compaction_unregister_node(struct node *node) |
| { |
| } |
| #endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */ |
| |
| #endif /* _LINUX_COMPACTION_H */ |