UNDERCODE COMMUNITY

Mm_strut is used to describe the process cache.

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 count;

int map_count; / * number of VMAs * /

struct semaphore mmap_sem;

spinlock_t page_table_lock;

unsigned long context;

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_;

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;

/ *

* This is an architecture-specific pointer: the portable

* part of Linux does not know about any segments.

* /

void * segments;

};

he describes the page directory of a process, context information about the process . And data. Code. The end address of the revelation of the stack. There are also the number of virtual storage acquisition. And the linked list pointer for scheduling storage. His

argument is higher. The higher level vm_area-struct is the virtual address area describing the process. Mathematical linked list. Arranged in descending order of virtual addresses. So when the kernel needs to perform a given operation on a given process page, the guest finds the item from the two-way list. In the world, it wants to deal with the page. For example. Page fault. Page change the like

his specific structure is as follows:

struct the vm_area_struct {

struct * mm_struct vm_mm; / * Parameters Area the VM * /

unsigned Long vm_start;

unsigned Long vm_end;

　

/ * linked per Task List Areas of the VM, the sorted by address * /

struct the vm_area_struct * vm_next;

　

pgprot_t vm_page_prot;

unsigned short 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 inode, the list inode-> i_mmap, 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_offset;

struct file * vm_file;

unsigned long vm_pte; / * shared mem * /

);

yes A data structure described by a physical page. He is not a real physical page. It only describes the content and frame of a physical page. It makes a mark for a logical page; his logo field defines this page in progress. The operation. The chain domain defines a double necklace table. The page frame can be easily found. For the actual physical memory until convenient.

Its specific structure is as follows

typedef struct page {

/ * these must be first (free area handling) * /

struct page * next;

struct page * prev;

struct inode * inode;

unsigned long offset;

struct page * next_hash;

atomic_t count;

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

wait_queue_head_t wait;

struct page ** pprev_hash;

struct buffer_head * buffers;

int owner; / * temporary debugging check * /

} mem_map_t;

all page structures will be transferred into an array called mem_map.

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