cregit-Linux how code gets into the kernel

Release 4.7 include/linux/compaction.h

Directory: include/linux
#ifndef _LINUX_COMPACTION_H

#define _LINUX_COMPACTION_H

/* 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,

	/* 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 */

#define COMPACT_CONTENDED_NONE	0
/* Either need_sched() was true or fatal signal pending */

#define COMPACT_CONTENDED_SCHED	1
/* Zone lock or lru_lock was contended in async compaction */

#define COMPACT_CONTENDED_LOCK	2

struct alloc_context; /* in mm/internal.h */

#ifdef CONFIG_COMPACTION
extern int sysctl_compact_memory;
extern int sysctl_compaction_handler(struct ctl_table *table, int write,
			void __user *buffer, size_t *length, loff_t *ppos);
extern int sysctl_extfrag_threshold;
extern int sysctl_extfrag_handler(struct ctl_table *table, int write,
			void __user *buffer, size_t *length, loff_t *ppos);
extern int sysctl_compact_unevictable_allowed;

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 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 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);
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; }

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michal hockomichal hocko24100.00%1100.00%
Total24100.00%1100.00%

/* 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; }

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michal hockomichal hocko24100.00%1100.00%
Total24100.00%1100.00%

/* * 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; }

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michal hockomichal hocko54100.00%1100.00%
Total54100.00%1100.00%

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 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) { return COMPACT_CONTINUE; }

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mel gormanmel gorman2057.14%342.86%
vlastimil babkavlastimil babka1028.57%228.57%
david rientjesdavid rientjes38.57%114.29%
michal hockomichal hocko25.71%114.29%
Total35100.00%7100.00%


static inline void compact_pgdat(pg_data_t *pgdat, int order) { }

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rik van rielrik van riel1184.62%150.00%
andrew mortonandrew morton215.38%150.00%
Total13100.00%2100.00%


static inline void reset_isolation_suitable(pg_data_t *pgdat) { }

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mel gormanmel gorman10100.00%1100.00%
Total10100.00%1100.00%


static inline enum compact_result compaction_suitable(struct zone *zone, int order, int alloc_flags, int classzone_idx) { return COMPACT_SKIPPED; }

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mel gormanmel gorman1768.00%133.33%
vlastimil babkavlastimil babka624.00%133.33%
michal hockomichal hocko28.00%133.33%
Total25100.00%3100.00%


static inline void defer_compaction(struct zone *zone, int order) { }

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mel gormanmel gorman1178.57%150.00%
rik van rielrik van riel321.43%150.00%
Total14100.00%2100.00%


static inline bool compaction_deferred(struct zone *zone, int order) { return true; }

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mel gormanmel gorman1477.78%133.33%
rik van rielrik van riel316.67%133.33%
gavin shangavin shan15.56%133.33%
Total18100.00%3100.00%


static inline bool compaction_made_progress(enum compact_result result) { return false; }

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michal hockomichal hocko14100.00%1100.00%
Total14100.00%1100.00%


static inline bool compaction_failed(enum compact_result result) { return false; }

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michal hockomichal hocko14100.00%1100.00%
Total14100.00%1100.00%


static inline bool compaction_withdrawn(enum compact_result result) { return true; }

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michal hockomichal hocko14100.00%1100.00%
Total14100.00%1100.00%


static inline int kcompactd_run(int nid) { return 0; }

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vlastimil babkavlastimil babka13100.00%1100.00%
Total13100.00%1100.00%


static inline void kcompactd_stop(int nid) { }

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vlastimil babkavlastimil babka9100.00%1100.00%
Total9100.00%1100.00%


static inline void wakeup_kcompactd(pg_data_t *pgdat, int order, int classzone_idx) { }

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vlastimil babkavlastimil babka16100.00%1100.00%
Total16100.00%1100.00%

#endif /* CONFIG_COMPACTION */ #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; }

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mel gormanmel gorman15100.00%1100.00%
Total15100.00%1100.00%


static inline void compaction_unregister_node(struct node *node) { }

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mel gormanmel gorman11100.00%1100.00%
Total11100.00%1100.00%

#endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */ #endif /* _LINUX_COMPACTION_H */

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mel gormanmel gorman29943.08%1135.48%
michal hockomichal hocko20229.11%619.35%
vlastimil babkavlastimil babka13719.74%722.58%
rik van rielrik van riel344.90%26.45%
joonsoo kimjoonsoo kim81.15%13.23%
david rientjesdavid rientjes60.86%13.23%
eric b munsoneric b munson40.58%13.23%
andrew mortonandrew morton30.43%13.23%
gavin shangavin shan10.14%13.23%
Total694100.00%31100.00%
Directory: include/linux
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