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

#ifndef _LINUX_MM_TYPES_H
#define _LINUX_MM_TYPES_H

#include <linux/types.h>
#include <linux/threads.h>
#include <linux/list.h>
#include <linux/spinlock.h>

struct address_space;

/*
 * Each physical page in the system has a struct page associated with
 * it to keep track of whatever it is we are using the page for at the
 * moment. Note that we have no way to track which tasks are using
 * a page, though if it is a pagecache page, rmap structures can tell us
 * who is mapping it.
 */
struct page {
	unsigned long flags;		/* Atomic flags, some possibly
					 * updated asynchronously */
	atomic_t _count;		/* Usage count, see below. */
	atomic_t _mapcount;		/* Count of ptes mapped in mms,
					 * to show when page is mapped
					 * & limit reverse map searches.
					 */
	union {
	    struct {
		unsigned long private;		/* Mapping-private opaque data:
					 	 * usually used for buffer_heads
						 * if PagePrivate set; used for
						 * swp_entry_t if PageSwapCache;
						 * indicates order in the buddy
						 * system if PG_buddy is set.
						 */
		struct address_space *mapping;	/* If low bit clear, points to
						 * inode address_space, or NULL.
						 * If page mapped as anonymous
						 * memory, low bit is set, and
						 * it points to anon_vma object:
						 * see PAGE_MAPPING_ANON below.
						 */
	    };
#if NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS
	    spinlock_t ptl;
#endif
	};
	pgoff_t index;			/* Our offset within mapping. */
	struct list_head lru;		/* Pageout list, eg. active_list
					 * protected by zone->lru_lock !
					 */
	/*
	 * On machines where all RAM is mapped into kernel address space,
	 * we can simply calculate the virtual address. On machines with
	 * highmem some memory is mapped into kernel virtual memory
	 * dynamically, so we need a place to store that address.
	 * Note that this field could be 16 bits on x86 ... ;)
	 *
	 * Architectures with slow multiplication can define
	 * WANT_PAGE_VIRTUAL in asm/page.h
	 */
#if defined(WANT_PAGE_VIRTUAL)
	void *virtual;			/* Kernel virtual address (NULL if
					   not kmapped, ie. highmem) */
#endif /* WANT_PAGE_VIRTUAL */
};

#endif /* _LINUX_MM_TYPES_H */
Commit	Line	Data
5b99cd0e HC	1	#ifndef _LINUX_MM_TYPES_H
	2	#define _LINUX_MM_TYPES_H
	3
	4	#include <linux/types.h>
	5	#include <linux/threads.h>
	6	#include <linux/list.h>
	7	#include <linux/spinlock.h>
	8
	9	struct address_space;
	10
	11	/*
	12	* Each physical page in the system has a struct page associated with
	13	* it to keep track of whatever it is we are using the page for at the
	14	* moment. Note that we have no way to track which tasks are using
	15	* a page, though if it is a pagecache page, rmap structures can tell us
	16	* who is mapping it.
	17	*/
	18	struct page {
	19	unsigned long flags; /* Atomic flags, some possibly
	20	* updated asynchronously */
	21	atomic_t _count; /* Usage count, see below. */
	22	atomic_t _mapcount; /* Count of ptes mapped in mms,
	23	* to show when page is mapped
	24	* & limit reverse map searches.
	25	*/
	26	union {
	27	struct {
	28	unsigned long private; /* Mapping-private opaque data:
	29	* usually used for buffer_heads
	30	* if PagePrivate set; used for
	31	* swp_entry_t if PageSwapCache;
	32	* indicates order in the buddy
	33	* system if PG_buddy is set.
	34	*/
	35	struct address_space mapping; / If low bit clear, points to
	36	* inode address_space, or NULL.
	37	* If page mapped as anonymous
	38	* memory, low bit is set, and
	39	* it points to anon_vma object:
	40	* see PAGE_MAPPING_ANON below.
	41	*/
	42	};
	43	#if NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS
	44	spinlock_t ptl;
	45	#endif
	46	};
	47	pgoff_t index; /* Our offset within mapping. */
	48	struct list_head lru; /* Pageout list, eg. active_list
	49	* protected by zone->lru_lock !
	50	*/
	51	/*
	52	* On machines where all RAM is mapped into kernel address space,
	53	* we can simply calculate the virtual address. On machines with
	54	* highmem some memory is mapped into kernel virtual memory
	55	* dynamically, so we need a place to store that address.
	56	* Note that this field could be 16 bits on x86 ... ;)
	57	*
	58	* Architectures with slow multiplication can define
	59	* WANT_PAGE_VIRTUAL in asm/page.h
	60	*/
	61	#if defined(WANT_PAGE_VIRTUAL)
	62	void virtual; / Kernel virtual address (NULL if
	63	not kmapped, ie. highmem) */
	64	#endif /* WANT_PAGE_VIRTUAL */
65	};
66
67	#endif /* _LINUX_MM_TYPES_H */