[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

#define COMPACT_MODE_DIRECT_RECLAIM	0
#define COMPACT_MODE_KSWAPD		1

#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,
					int compact_mode);

/* 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,
					       int compact_mode)
{
	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
5a03b051 AA	14	#define COMPACT_MODE_DIRECT_RECLAIM 0
	15	#define COMPACT_MODE_KSWAPD 1
	16
76ab0f53 MG	17	#ifdef CONFIG_COMPACTION
	18	extern int sysctl_compact_memory;
	19	extern int sysctl_compaction_handler(struct ctl_table *table, int write,
	20	void __user buffer, size_t length, loff_t *ppos);
5e771905 MG	21	extern int sysctl_extfrag_threshold;
	22	extern int sysctl_extfrag_handler(struct ctl_table *table, int write,
	23	void __user buffer, size_t length, loff_t *ppos);
56de7263 MG	24
	25	extern int fragmentation_index(struct zone *zone, unsigned int order);
	26	extern unsigned long try_to_compact_pages(struct zonelist *zonelist,
77f1fe6b MG	27	int order, gfp_t gfp_mask, nodemask_t *mask,
77f1fe6b MG	28	bool sync);
3e7d3449 MG	29	extern unsigned long compaction_suitable(struct zone *zone, int order);
3e7d3449 MG	30	extern unsigned long compact_zone_order(struct zone *zone, int order,
5a03b051 AA	31	gfp_t gfp_mask, bool sync,
5a03b051 AA	32	int compact_mode);
4f92e258 MG	33
	34	/* Do not skip compaction more than 64 times */
	35	#define COMPACT_MAX_DEFER_SHIFT 6
	36
	37	/*
	38	* Compaction is deferred when compaction fails to result in a page
	39	* allocation success. 1 << compact_defer_limit compactions are skipped up
	40	* to a limit of 1 << COMPACT_MAX_DEFER_SHIFT
	41	*/
	42	static inline void defer_compaction(struct zone *zone)
	43	{
	44	zone->compact_considered = 0;
	45	zone->compact_defer_shift++;
	46
	47	if (zone->compact_defer_shift > COMPACT_MAX_DEFER_SHIFT)
	48	zone->compact_defer_shift = COMPACT_MAX_DEFER_SHIFT;
	49	}
	50
	51	/* Returns true if compaction should be skipped this time */
	52	static inline bool compaction_deferred(struct zone *zone)
	53	{
	54	unsigned long defer_limit = 1UL << zone->compact_defer_shift;
	55
	56	/* Avoid possible overflow */
	57	if (++zone->compact_considered > defer_limit)
	58	zone->compact_considered = defer_limit;
	59
	60	return zone->compact_considered < (1UL << zone->compact_defer_shift);
	61	}
	62
56de7263 MG	63	#else
56de7263 MG	64	static inline unsigned long try_to_compact_pages(struct zonelist *zonelist,
77f1fe6b MG	65	int order, gfp_t gfp_mask, nodemask_t *nodemask,
77f1fe6b MG	66	bool sync)
56de7263 MG	67	{
	68	return COMPACT_CONTINUE;
	69	}
	70
3e7d3449 MG	71	static inline unsigned long compaction_suitable(struct zone *zone, int order)
	72	{
	73	return COMPACT_SKIPPED;
	74	}
	75
	76	static inline unsigned long compact_zone_order(struct zone *zone, int order,
5a03b051 AA	77	gfp_t gfp_mask, bool sync,
5a03b051 AA	78	int compact_mode)
3e7d3449	79	{
5a03b051	80	return COMPACT_CONTINUE;
3e7d3449 MG	81	}
3e7d3449 MG	82
4f92e258 MG	83	static inline void defer_compaction(struct zone *zone)
	84	{
	85	}
	86
	87	static inline bool compaction_deferred(struct zone *zone)
	88	{
	89	return 1;
	90	}
	91
76ab0f53 MG	92	#endif /* CONFIG_COMPACTION */
76ab0f53 MG	93
ed4a6d7f MG	94	#if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
	95	extern int compaction_register_node(struct node *node);
	96	extern void compaction_unregister_node(struct node *node);
	97
	98	#else
	99
	100	static inline int compaction_register_node(struct node *node)
	101	{
	102	return 0;
	103	}
	104
	105	static inline void compaction_unregister_node(struct node *node)
	106	{
	107	}
	108	#endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */
	109
748446bb	110	#endif /* _LINUX_COMPACTION_H */