Contributors: 19
	  
        
          | Author | 
          Tokens | 
          Token Proportion | 
          Commits | 
          Commit Proportion | 
        
	  
	  
        
        
          | Mel Gorman | 
          152 | 
          38.78% | 
          11 | 
          20.37% | 
        
        
          | Vlastimil Babka | 
          122 | 
          31.12% | 
          12 | 
          22.22% | 
        
        
          | Michal Hocko | 
          25 | 
          6.38% | 
          4 | 
          7.41% | 
        
        
          | Andrew Morton | 
          23 | 
          5.87% | 
          6 | 
          11.11% | 
        
        
          | Keiichiro Tokunaga | 
          18 | 
          4.59% | 
          1 | 
          1.85% | 
        
        
          | Rik Van Riel | 
          12 | 
          3.06% | 
          1 | 
          1.85% | 
        
        
          | JoonSoo Kim | 
          8 | 
          2.04% | 
          3 | 
          5.56% | 
        
        
          | Linus Torvalds (pre-git) | 
          5 | 
          1.28% | 
          3 | 
          5.56% | 
        
        
          | David Howells | 
          4 | 
          1.02% | 
          1 | 
          1.85% | 
        
        
          | Nitin Gupta | 
          4 | 
          1.02% | 
          2 | 
          3.70% | 
        
        
          | Miaohe Lin | 
          4 | 
          1.02% | 
          2 | 
          3.70% | 
        
        
          | Nicholas Piggin | 
          3 | 
          0.77% | 
          1 | 
          1.85% | 
        
        
          | MinChan Kim | 
          3 | 
          0.77% | 
          1 | 
          1.85% | 
        
        
          | Johannes Weiner | 
          3 | 
          0.77% | 
          1 | 
          1.85% | 
        
        
          | Zhen Lei | 
          2 | 
          0.51% | 
          1 | 
          1.85% | 
        
        
          | David Rientjes | 
          1 | 
          0.26% | 
          1 | 
          1.85% | 
        
        
          | Martin Hicks | 
          1 | 
          0.26% | 
          1 | 
          1.85% | 
        
        
          | Greg Kroah-Hartman | 
          1 | 
          0.26% | 
          1 | 
          1.85% | 
        
        
          | Lee Schermerhorn | 
          1 | 
          0.26% | 
          1 | 
          1.85% | 
        
	  
	  
        
          | Total | 
          392 | 
           | 
          54 | 
           | 
	    
	  
    
 
/* 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 successful to compact
	 * suitable pages.
	 */
	COMPACT_COMPLETE,
	/*
	 * direct compaction has scanned part of the zone but wasn't successful
	 * 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 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 bool compaction_suitable(struct zone *zone, int order,
					       int highest_zoneidx);
extern void compaction_defer_reset(struct zone *zone, int order,
				bool alloc_success);
bool compaction_zonelist_suitable(struct alloc_context *ac, int order,
					int alloc_flags);
extern void __meminit kcompactd_run(int nid);
extern void __meminit 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 bool compaction_suitable(struct zone *zone, int order,
						      int highest_zoneidx)
{
	return false;
}
static inline void kcompactd_run(int nid)
{
}
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 */