[mirror_ubuntu-zesty-kernel.git] / include / linux / compaction.h

#ifndef _LINUX_COMPACTION_H
#define _LINUX_COMPACTION_H

/* Return values for compact_zone() and try_to_compact_pages() */
/* compaction didn't start as it was not possible or direct reclaim was more suitable */
#define COMPACT_SKIPPED		0
/* compaction should continue to another pageblock */
#define COMPACT_CONTINUE	1
/* direct compaction partially compacted a zone and there are suitable pages */
#define COMPACT_PARTIAL		2
/* The full zone was compacted */
#define COMPACT_COMPLETE	3

#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 fragmentation_index(struct zone *zone, unsigned int order);
extern unsigned long try_to_compact_pages(struct zonelist *zonelist,
			int order, gfp_t gfp_mask, nodemask_t *mask,
			bool sync);
extern unsigned long compaction_suitable(struct zone *zone, int order);
extern unsigned long compact_zone_order(struct zone *zone, int order,
					gfp_t gfp_mask, bool sync);

/* Do not skip compaction more than 64 times */
#define COMPACT_MAX_DEFER_SHIFT 6

/*
 * Compaction is deferred when compaction fails to result in a page
 * allocation success. 1 << compact_defer_limit compactions are skipped up
 * to a limit of 1 << COMPACT_MAX_DEFER_SHIFT
 */
static inline void defer_compaction(struct zone *zone)
{
	zone->compact_considered = 0;
	zone->compact_defer_shift++;

	if (zone->compact_defer_shift > COMPACT_MAX_DEFER_SHIFT)
		zone->compact_defer_shift = COMPACT_MAX_DEFER_SHIFT;
}

/* Returns true if compaction should be skipped this time */
static inline bool compaction_deferred(struct zone *zone)
{
	unsigned long defer_limit = 1UL << zone->compact_defer_shift;

	/* Avoid possible overflow */
	if (++zone->compact_considered > defer_limit)
		zone->compact_considered = defer_limit;

	return zone->compact_considered < (1UL << zone->compact_defer_shift);
}

#else
static inline unsigned long try_to_compact_pages(struct zonelist *zonelist,
			int order, gfp_t gfp_mask, nodemask_t *nodemask,
			bool sync)
{
	return COMPACT_CONTINUE;
}

static inline unsigned long compaction_suitable(struct zone *zone, int order)
{
	return COMPACT_SKIPPED;
}

static inline unsigned long compact_zone_order(struct zone *zone, int order,
					       gfp_t gfp_mask, bool sync)
{
	return COMPACT_CONTINUE;
}

static inline void defer_compaction(struct zone *zone)
{
}

static inline bool compaction_deferred(struct zone *zone)
{
	return 1;
}

#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;
}

static inline void compaction_unregister_node(struct node *node)
{
}
#endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */

#endif /* _LINUX_COMPACTION_H */
Commit	Line	Data
748446bb MG	1	#ifndef _LINUX_COMPACTION_H
	2	#define _LINUX_COMPACTION_H
	3
56de7263 MG	4	/* Return values for compact_zone() and try_to_compact_pages() */
	5	/* compaction didn't start as it was not possible or direct reclaim was more suitable */
	6	#define COMPACT_SKIPPED 0
	7	/* compaction should continue to another pageblock */
	8	#define COMPACT_CONTINUE 1
	9	/* direct compaction partially compacted a zone and there are suitable pages */
	10	#define COMPACT_PARTIAL 2
	11	/* The full zone was compacted */
	12	#define COMPACT_COMPLETE 3
748446bb	13
76ab0f53 MG	14	#ifdef CONFIG_COMPACTION
	15	extern int sysctl_compact_memory;
	16	extern int sysctl_compaction_handler(struct ctl_table *table, int write,
	17	void __user buffer, size_t length, loff_t *ppos);
5e771905 MG	18	extern int sysctl_extfrag_threshold;
	19	extern int sysctl_extfrag_handler(struct ctl_table *table, int write,
	20	void __user buffer, size_t length, loff_t *ppos);
56de7263 MG	21
	22	extern int fragmentation_index(struct zone *zone, unsigned int order);
	23	extern unsigned long try_to_compact_pages(struct zonelist *zonelist,
77f1fe6b MG	24	int order, gfp_t gfp_mask, nodemask_t *mask,
77f1fe6b MG	25	bool sync);
3e7d3449 MG	26	extern unsigned long compaction_suitable(struct zone *zone, int order);
3e7d3449 MG	27	extern unsigned long compact_zone_order(struct zone *zone, int order,
d527caf2	28	gfp_t gfp_mask, bool sync);
4f92e258 MG	29
	30	/* Do not skip compaction more than 64 times */
	31	#define COMPACT_MAX_DEFER_SHIFT 6
	32
	33	/*
	34	* Compaction is deferred when compaction fails to result in a page
	35	* allocation success. 1 << compact_defer_limit compactions are skipped up
	36	* to a limit of 1 << COMPACT_MAX_DEFER_SHIFT
	37	*/
	38	static inline void defer_compaction(struct zone *zone)
	39	{
	40	zone->compact_considered = 0;
	41	zone->compact_defer_shift++;
	42
	43	if (zone->compact_defer_shift > COMPACT_MAX_DEFER_SHIFT)
	44	zone->compact_defer_shift = COMPACT_MAX_DEFER_SHIFT;
	45	}
	46
	47	/* Returns true if compaction should be skipped this time */
	48	static inline bool compaction_deferred(struct zone *zone)
	49	{
	50	unsigned long defer_limit = 1UL << zone->compact_defer_shift;
	51
	52	/* Avoid possible overflow */
	53	if (++zone->compact_considered > defer_limit)
	54	zone->compact_considered = defer_limit;
	55
	56	return zone->compact_considered < (1UL << zone->compact_defer_shift);
	57	}
	58
56de7263 MG	59	#else
56de7263 MG	60	static inline unsigned long try_to_compact_pages(struct zonelist *zonelist,
77f1fe6b MG	61	int order, gfp_t gfp_mask, nodemask_t *nodemask,
77f1fe6b MG	62	bool sync)
56de7263 MG	63	{
	64	return COMPACT_CONTINUE;
	65	}
	66
3e7d3449 MG	67	static inline unsigned long compaction_suitable(struct zone *zone, int order)
	68	{
	69	return COMPACT_SKIPPED;
	70	}
	71
	72	static inline unsigned long compact_zone_order(struct zone *zone, int order,
d527caf2	73	gfp_t gfp_mask, bool sync)
3e7d3449	74	{
5a03b051	75	return COMPACT_CONTINUE;
3e7d3449 MG	76	}
3e7d3449 MG	77
4f92e258 MG	78	static inline void defer_compaction(struct zone *zone)
	79	{
	80	}
	81
	82	static inline bool compaction_deferred(struct zone *zone)
	83	{
	84	return 1;
	85	}
	86
76ab0f53 MG	87	#endif /* CONFIG_COMPACTION */
76ab0f53 MG	88
ed4a6d7f MG	89	#if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
	90	extern int compaction_register_node(struct node *node);
	91	extern void compaction_unregister_node(struct node *node);
	92
	93	#else
	94
	95	static inline int compaction_register_node(struct node *node)
	96	{
	97	return 0;
	98	}
	99
	100	static inline void compaction_unregister_node(struct node *node)
	101	{
	102	}
	103	#endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */
	104
748446bb	105	#endif /* _LINUX_COMPACTION_H */