[linux-2.6-block.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 int compact_pgdat(pg_data_t *pgdat, int order);
extern unsigned long compaction_suitable(struct zone *zone, int order);

/* 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, int order)
{
	zone->compact_considered = 0;
	zone->compact_defer_shift++;

	if (order < zone->compact_order_failed)
		zone->compact_order_failed = order;

	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, int order)
{
	unsigned long defer_limit = 1UL << zone->compact_defer_shift;

	if (order < zone->compact_order_failed)
		return false;

	/* 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 int compact_pgdat(pg_data_t *pgdat, int order)
{
	return COMPACT_CONTINUE;
}

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

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

static inline bool compaction_deferred(struct zone *zone, int order)
{
	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);
7be62de9	26	extern int compact_pgdat(pg_data_t *pgdat, int order);
3e7d3449	27	extern unsigned long compaction_suitable(struct zone *zone, int order);
4f92e258 MG	28
	29	/* Do not skip compaction more than 64 times */
	30	#define COMPACT_MAX_DEFER_SHIFT 6
	31
	32	/*
	33	* Compaction is deferred when compaction fails to result in a page
	34	* allocation success. 1 << compact_defer_limit compactions are skipped up
	35	* to a limit of 1 << COMPACT_MAX_DEFER_SHIFT
	36	*/
aff62249	37	static inline void defer_compaction(struct zone *zone, int order)
4f92e258 MG	38	{
	39	zone->compact_considered = 0;
	40	zone->compact_defer_shift++;
	41
aff62249 RR	42	if (order < zone->compact_order_failed)
	43	zone->compact_order_failed = order;
	44
4f92e258 MG	45	if (zone->compact_defer_shift > COMPACT_MAX_DEFER_SHIFT)
	46	zone->compact_defer_shift = COMPACT_MAX_DEFER_SHIFT;
	47	}
	48
	49	/* Returns true if compaction should be skipped this time */
aff62249	50	static inline bool compaction_deferred(struct zone *zone, int order)
4f92e258 MG	51	{
	52	unsigned long defer_limit = 1UL << zone->compact_defer_shift;
	53
aff62249 RR	54	if (order < zone->compact_order_failed)
	55	return false;
	56
4f92e258 MG	57	/* Avoid possible overflow */
	58	if (++zone->compact_considered > defer_limit)
	59	zone->compact_considered = defer_limit;
	60
	61	return zone->compact_considered < (1UL << zone->compact_defer_shift);
	62	}
	63
56de7263 MG	64	#else
56de7263 MG	65	static inline unsigned long try_to_compact_pages(struct zonelist *zonelist,
77f1fe6b MG	66	int order, gfp_t gfp_mask, nodemask_t *nodemask,
77f1fe6b MG	67	bool sync)
56de7263 MG	68	{
	69	return COMPACT_CONTINUE;
	70	}
	71
7be62de9 RR	72	static inline int compact_pgdat(pg_data_t *pgdat, int order)
	73	{
	74	return COMPACT_CONTINUE;
	75	}
	76
3e7d3449 MG	77	static inline unsigned long compaction_suitable(struct zone *zone, int order)
	78	{
	79	return COMPACT_SKIPPED;
	80	}
	81
aff62249	82	static inline void defer_compaction(struct zone *zone, int order)
4f92e258 MG	83	{
	84	}
	85
aff62249	86	static inline bool compaction_deferred(struct zone *zone, int order)
4f92e258 MG	87	{
	88	return 1;
	89	}
	90
76ab0f53 MG	91	#endif /* CONFIG_COMPACTION */
76ab0f53 MG	92
ed4a6d7f MG	93	#if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
	94	extern int compaction_register_node(struct node *node);
	95	extern void compaction_unregister_node(struct node *node);
	96
	97	#else
	98
	99	static inline int compaction_register_node(struct node *node)
	100	{
	101	return 0;
	102	}
	103
	104	static inline void compaction_unregister_node(struct node *node)
	105	{
	106	}
	107	#endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */
	108
748446bb	109	#endif /* _LINUX_COMPACTION_H */