/*

 * Try to keep the most commonly accessed fields in single cache lines

 * here (16 bytes or greater).  This ordering should be particularly

 * beneficial on 32-bit processors.

 *

 * The first line is data used in page cache lookup, the second line

 * is used for linear searches (eg. clock algorithm scans).

 */

typedef struct page {

    struct list_head list;

    struct address_space *mapping;

    unsigned long index;

    struct page *next_hash;

    atomic_t count;

    unsigned long flags;       /* atomic flags, some possibly updated asynchronously */

    struct list_head lru;

    unsigned long age;

    wait_queue_head_t wait;

    struct page **pprev_hash;

    struct buffer_head * buffers;

    void *virtual;             /* non-NULL if kmapped */

    struct zone_struct *zone;

} mem_map_t;

/*

 * Linux kernel virtual memory manager primitives.

 * The idea being to have a "virtual" mm in the same way

 * we have a virtual fs - giving a cleaner interface to the

 * mm details, and allowing different kinds of memory mappings

 * (from shared memory to executable loading to arbitrary

 * mmap() functions).

 */

/*

 * This struct defines a memory VMM memory area. There is one of these

 * per VM-area/task.  A VM area is any part of the process virtual memory

 * space that has a special rule for the page-fault handlers (ie a shared

 * library, the executable area etc).

 */

struct vm_area_struct {

    struct mm_struct * vm_mm;    /* VM area parameters */

    unsigned long vm_start;

    unsigned long vm_end;

    /* linked list of VM areas per task, sorted by address */

    struct vm_area_struct *vm_next;

    pgprot_t vm_page_prot;

    unsigned long vm_flags;

    /* AVL tree of VM areas per task, sorted by address */

    short vm_avl_height;

    struct vm_area_struct * vm_avl_left;

    struct vm_area_struct * vm_avl_right;

    /* For areas with an address space and backing store,

     * one of the address_space->i_mmap{,shared} lists,

     * for shm areas, the list of attaches, otherwise unused.

     */

    struct vm_area_struct *vm_next_share;

    struct vm_area_struct **vm_pprev_share;

    struct vm_operations_struct * vm_ops;

    unsigned long vm_pgoff;        /* offset in PAGE_SIZE units, *not* PAGE_CACHE_SIZE */

    struct file * vm_file;

    unsigned long vm_raend;

    void * vm_private_data;        /* was vm_pte (shared mem) */

};

struct mm_struct {

    struct vm_area_struct * mmap;        /* list of VMAs */

    struct vm_area_struct * mmap_avl;    /* tree of VMAs */

    struct vm_area_struct * mmap_cache;    /* last find_vma result */

    pgd_t * pgd;

    atomic_t mm_users;            /* How many users with user space? */

    atomic_t mm_count;            /* How many references to "struct mm_struct" (users count as 1) */

    int map_count;                /* number of VMAs */

    struct semaphore mmap_sem;

    spinlock_t page_table_lock;

    struct list_head mmlist;        /* List of all active mm's */

    unsigned long start_code, end_code, start_data, end_data;

    unsigned long start_brk, brk, start_stack;

    unsigned long arg_start, arg_end, env_start, env_end;

    unsigned long rss, total_vm, locked_vm;

    unsigned long def_flags;

    unsigned long cpu_vm_mask;

    unsigned long swap_cnt;  /* number of pages to swap on next pass */

    unsigned long swap_address;

    /* Architecture-specific MM context */

    mm_context_t context;

};