[net-next-2.6.git] / include / linux / rmap.h

#ifndef _LINUX_RMAP_H
#define _LINUX_RMAP_H
/*
 * Declarations for Reverse Mapping functions in mm/rmap.c
 */

#include <linux/list.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/spinlock.h>

/*
 * The anon_vma heads a list of private "related" vmas, to scan if
 * an anonymous page pointing to this anon_vma needs to be unmapped:
 * the vmas on the list will be related by forking, or by splitting.
 *
 * Since vmas come and go as they are split and merged (particularly
 * in mprotect), the mapping field of an anonymous page cannot point
 * directly to a vma: instead it points to an anon_vma, on whose list
 * the related vmas can be easily linked or unlinked.
 *
 * After unlinking the last vma on the list, we must garbage collect
 * the anon_vma object itself: we're guaranteed no page can be
 * pointing to this anon_vma once its vma list is empty.
 */
struct anon_vma {
	spinlock_t lock;	/* Serialize access to vma list */
	struct list_head head;	/* List of private "related" vmas */
};

#ifdef CONFIG_MMU

extern struct kmem_cache *anon_vma_cachep;

static inline struct anon_vma *anon_vma_alloc(void)
{
	return kmem_cache_alloc(anon_vma_cachep, GFP_KERNEL);
}

static inline void anon_vma_free(struct anon_vma *anon_vma)
{
	kmem_cache_free(anon_vma_cachep, anon_vma);
}

static inline void anon_vma_lock(struct vm_area_struct *vma)
{
	struct anon_vma *anon_vma = vma->anon_vma;
	if (anon_vma)
		spin_lock(&anon_vma->lock);
}

static inline void anon_vma_unlock(struct vm_area_struct *vma)
{
	struct anon_vma *anon_vma = vma->anon_vma;
	if (anon_vma)
		spin_unlock(&anon_vma->lock);
}

/*
 * anon_vma helper functions.
 */
void anon_vma_init(void);	/* create anon_vma_cachep */
int  anon_vma_prepare(struct vm_area_struct *);
void __anon_vma_merge(struct vm_area_struct *, struct vm_area_struct *);
void anon_vma_unlink(struct vm_area_struct *);
void anon_vma_link(struct vm_area_struct *);
void __anon_vma_link(struct vm_area_struct *);

/*
 * rmap interfaces called when adding or removing pte of page
 */
void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
void page_add_file_rmap(struct page *);
void page_remove_rmap(struct page *, struct vm_area_struct *);

#ifdef CONFIG_DEBUG_VM
void page_dup_rmap(struct page *page, struct vm_area_struct *vma, unsigned long address);
#else
static inline void page_dup_rmap(struct page *page, struct vm_area_struct *vma, unsigned long address)
{
	atomic_inc(&page->_mapcount);
}
#endif

/*
 * Called from mm/vmscan.c to handle paging out
 */
int page_referenced(struct page *, int is_locked);
int try_to_unmap(struct page *, int ignore_refs);

/*
 * Called from mm/filemap_xip.c to unmap empty zero page
 */
pte_t *page_check_address(struct page *, struct mm_struct *,
				unsigned long, spinlock_t **);

/*
 * Used by swapoff to help locate where page is expected in vma.
 */
unsigned long page_address_in_vma(struct page *, struct vm_area_struct *);

/*
 * Cleans the PTEs of shared mappings.
 * (and since clean PTEs should also be readonly, write protects them too)
 *
 * returns the number of cleaned PTEs.
 */
int page_mkclean(struct page *);

#else	/* !CONFIG_MMU */

#define anon_vma_init()		do {} while (0)
#define anon_vma_prepare(vma)	(0)
#define anon_vma_link(vma)	do {} while (0)

#define page_referenced(page,l) TestClearPageReferenced(page)
#define try_to_unmap(page, refs) SWAP_FAIL

static inline int page_mkclean(struct page *page)
{
	return 0;
}


#endif	/* CONFIG_MMU */

/*
 * Return values of try_to_unmap
 */
#define SWAP_SUCCESS	0
#define SWAP_AGAIN	1
#define SWAP_FAIL	2

#endif	/* _LINUX_RMAP_H */
Commit	Line	Data
1da177e4 LT	1	#ifndef _LINUX_RMAP_H
	2	#define _LINUX_RMAP_H
	3	/*
	4	* Declarations for Reverse Mapping functions in mm/rmap.c
	5	*/
	6
1da177e4 LT	7	#include <linux/list.h>
	8	#include <linux/slab.h>
	9	#include <linux/mm.h>
	10	#include <linux/spinlock.h>
	11
	12	/*
	13	* The anon_vma heads a list of private "related" vmas, to scan if
	14	* an anonymous page pointing to this anon_vma needs to be unmapped:
	15	* the vmas on the list will be related by forking, or by splitting.
	16	*
	17	* Since vmas come and go as they are split and merged (particularly
	18	* in mprotect), the mapping field of an anonymous page cannot point
	19	* directly to a vma: instead it points to an anon_vma, on whose list
	20	* the related vmas can be easily linked or unlinked.
	21	*
	22	* After unlinking the last vma on the list, we must garbage collect
	23	* the anon_vma object itself: we're guaranteed no page can be
	24	* pointing to this anon_vma once its vma list is empty.
	25	*/
	26	struct anon_vma {
	27	spinlock_t lock; /* Serialize access to vma list */
	28	struct list_head head; /* List of private "related" vmas */
	29	};
	30
	31	#ifdef CONFIG_MMU
	32
e18b890b	33	extern struct kmem_cache *anon_vma_cachep;
1da177e4 LT	34
	35	static inline struct anon_vma *anon_vma_alloc(void)
	36	{
e94b1766	37	return kmem_cache_alloc(anon_vma_cachep, GFP_KERNEL);
1da177e4 LT	38	}
	39
	40	static inline void anon_vma_free(struct anon_vma *anon_vma)
	41	{
	42	kmem_cache_free(anon_vma_cachep, anon_vma);
	43	}
	44
	45	static inline void anon_vma_lock(struct vm_area_struct *vma)
	46	{
	47	struct anon_vma *anon_vma = vma->anon_vma;
	48	if (anon_vma)
	49	spin_lock(&anon_vma->lock);
	50	}
	51
	52	static inline void anon_vma_unlock(struct vm_area_struct *vma)
	53	{
	54	struct anon_vma *anon_vma = vma->anon_vma;
	55	if (anon_vma)
	56	spin_unlock(&anon_vma->lock);
	57	}
	58
	59	/*
	60	* anon_vma helper functions.
	61	*/
	62	void anon_vma_init(void); /* create anon_vma_cachep */
	63	int anon_vma_prepare(struct vm_area_struct *);
	64	void __anon_vma_merge(struct vm_area_struct , struct vm_area_struct );
	65	void anon_vma_unlink(struct vm_area_struct *);
	66	void anon_vma_link(struct vm_area_struct *);
	67	void __anon_vma_link(struct vm_area_struct *);
	68
	69	/*
	70	* rmap interfaces called when adding or removing pte of page
	71	*/
	72	void page_add_anon_rmap(struct page , struct vm_area_struct , unsigned long);
9617d95e	73	void page_add_new_anon_rmap(struct page , struct vm_area_struct , unsigned long);
1da177e4	74	void page_add_file_rmap(struct page *);
7de6b805	75	void page_remove_rmap(struct page , struct vm_area_struct );
1da177e4	76
c97a9e10 NP	77	#ifdef CONFIG_DEBUG_VM
	78	void page_dup_rmap(struct page page, struct vm_area_struct vma, unsigned long address);
	79	#else
	80	static inline void page_dup_rmap(struct page page, struct vm_area_struct vma, unsigned long address)
1da177e4 LT	81	{
	82	atomic_inc(&page->_mapcount);
	83	}
c97a9e10	84	#endif
1da177e4 LT	85
	86	/*
	87	* Called from mm/vmscan.c to handle paging out
	88	*/
f7b7fd8f	89	int page_referenced(struct page *, int is_locked);
a48d07af	90	int try_to_unmap(struct page *, int ignore_refs);
1da177e4	91
ceffc078 CO	92	/*
	93	* Called from mm/filemap_xip.c to unmap empty zero page
	94	*/
c0718806 HD	95	pte_t page_check_address(struct page , struct mm_struct *,
c0718806 HD	96	unsigned long, spinlock_t **);
ceffc078	97
1da177e4 LT	98	/*
	99	* Used by swapoff to help locate where page is expected in vma.
	100	*/
	101	unsigned long page_address_in_vma(struct page , struct vm_area_struct );
	102
d08b3851 PZ	103	/*
	104	* Cleans the PTEs of shared mappings.
	105	* (and since clean PTEs should also be readonly, write protects them too)
	106	*
	107	* returns the number of cleaned PTEs.
	108	*/
	109	int page_mkclean(struct page *);
	110
1da177e4 LT	111	#else /* !CONFIG_MMU */
	112
	113	#define anon_vma_init() do {} while (0)
	114	#define anon_vma_prepare(vma) (0)
	115	#define anon_vma_link(vma) do {} while (0)
	116
f7b7fd8f	117	#define page_referenced(page,l) TestClearPageReferenced(page)
a48d07af	118	#define try_to_unmap(page, refs) SWAP_FAIL
1da177e4	119
d08b3851 PZ	120	static inline int page_mkclean(struct page *page)
	121	{
	122	return 0;
	123	}
	124
	125
1da177e4 LT	126	#endif /* CONFIG_MMU */
	127
	128	/*
	129	* Return values of try_to_unmap
	130	*/
	131	#define SWAP_SUCCESS 0
	132	#define SWAP_AGAIN 1
	133	#define SWAP_FAIL 2
	134
	135	#endif /* _LINUX_RMAP_H */