diff options
Diffstat (limited to 'include/linux/compaction.h')
| -rw-r--r-- | include/linux/compaction.h | 151 |
1 files changed, 130 insertions, 21 deletions
diff --git a/include/linux/compaction.h b/include/linux/compaction.h index d7c8de583a23..a58c852a268f 100644 --- a/include/linux/compaction.h +++ b/include/linux/compaction.h @@ -2,21 +2,46 @@ #define _LINUX_COMPACTION_H /* Return values for compact_zone() and try_to_compact_pages() */ -/* compaction didn't start as it was deferred due to past failures */ -#define COMPACT_DEFERRED 0 -/* compaction didn't start as it was not possible or direct reclaim was more suitable */ -#define COMPACT_SKIPPED 1 -/* compaction should continue to another pageblock */ -#define COMPACT_CONTINUE 2 -/* direct compaction partially compacted a zone and there are suitable pages */ -#define COMPACT_PARTIAL 3 -/* The full zone was compacted */ -#define COMPACT_COMPLETE 4 -/* For more detailed tracepoint output */ -#define COMPACT_NO_SUITABLE_PAGE 5 -#define COMPACT_NOT_SUITABLE_ZONE 6 -#define COMPACT_CONTENDED 7 /* 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, + + /* compaction not active last round */ + COMPACT_INACTIVE = 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 partially compacted a zone and there might be + * suitable pages + */ + COMPACT_PARTIAL, +}; /* Used to signal whether compaction detected need_sched() or lock contention */ /* No contention detected */ @@ -38,13 +63,14 @@ extern int sysctl_extfrag_handler(struct ctl_table *table, int write, extern int sysctl_compact_unevictable_allowed; extern int fragmentation_index(struct zone *zone, unsigned int order); -extern unsigned long try_to_compact_pages(gfp_t gfp_mask, unsigned int order, - int alloc_flags, const struct alloc_context *ac, - enum migrate_mode mode, int *contended); +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 migrate_mode mode, int *contended); extern void compact_pgdat(pg_data_t *pgdat, int order); extern void reset_isolation_suitable(pg_data_t *pgdat); -extern unsigned long compaction_suitable(struct zone *zone, int order, - int alloc_flags, int classzone_idx); +extern enum compact_result compaction_suitable(struct zone *zone, int order, + unsigned int alloc_flags, int classzone_idx); extern void defer_compaction(struct zone *zone, int order); extern bool compaction_deferred(struct zone *zone, int order); @@ -52,12 +78,80 @@ extern void compaction_defer_reset(struct zone *zone, int order, bool alloc_success); extern bool compaction_restarting(struct zone *zone, int order); +/* 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_PARTIAL) + 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 has backed off for some reason. It might be throttling or + * lock contention. Retrying is still worthwhile. + */ +static inline bool compaction_withdrawn(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; + + /* + * 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 classzone_idx); #else -static inline unsigned long try_to_compact_pages(gfp_t gfp_mask, +static inline enum compact_result try_to_compact_pages(gfp_t gfp_mask, unsigned int order, int alloc_flags, const struct alloc_context *ac, enum migrate_mode mode, int *contended) @@ -73,7 +167,7 @@ static inline void reset_isolation_suitable(pg_data_t *pgdat) { } -static inline unsigned long compaction_suitable(struct zone *zone, int order, +static inline enum compact_result compaction_suitable(struct zone *zone, int order, int alloc_flags, int classzone_idx) { return COMPACT_SKIPPED; @@ -88,6 +182,21 @@ static inline bool compaction_deferred(struct zone *zone, int order) return true; } +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_withdrawn(enum compact_result result) +{ + return true; +} + static inline int kcompactd_run(int nid) { return 0; |