haiku/docs/develop/kernel/vm_page
ejakowatz 52a3801208 It is accomplished ...
git-svn-id: file:///srv/svn/repos/haiku/trunk/current@10 a95241bf-73f2-0310-859d-f6bbb57e9c96
2002-07-09 12:24:59 +00:00

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Variables
extern bool trimming_cycle;
Determines if we are trimming - if we are nearly out of space
static page_queue page_free_queue;
The queue that holds unused (but not cleared) pages
static page_queue page_clear_queue;
The queue that holds cleared (0'ed) pages
static page_queue page_modified_queue;
The queue that holds altered pages
static page_queue page_active_queue;
The queue that holds in use pages that are not altered
static vm_page *all_pages;
Every page in the system
static addr physical_page_offset;
The first address of real ram
static unsigned int num_pages;
Total number of pages in the system
static spinlock_t page_lock;
A lock to protect the queues.
static sem_id modified_pages_available;
A semaphore to indicate if there are pages that need to be written to disk
static void clear_page(addr pa);
Sets all values in this page to 0.
static vm_page * dequeue_page(page_queue *q)
Standard queue remove first page; has count; no locking
void dump_page_stats(int argc, char **argv);
Dumps counts of each state (active, inactive, busy, not used, modified, free, cleared, wired)
void dump_free_page_table(int argc, char **argv)
Not done.
static void enqueue_page(page_queue *q, vm_page *page)
Standard queue add a page; has count; no locking; SPECIAL - for page_modified_queue, if there is only one page modified (new one), release semaphore
static bool is_page_in_phys_range(kernel_args *ka, addr paddr)
Determines if a physical address is in the physical memory that exists.
static void move_page_to_queue(page_queue *from_q, page_queue *to_q, vm_page *page)
Removes the page from the from_q and adds it to the to_q.
static int pageout_daemon()
aquires the "modified pages available" semaphore. Gets first page from modified list. Sets it to busy, updates all processes mapping this page that it is no longer a modified page, writes it out to disk, then puts it on the active list (i.e. not modified). Doesn't write out "anonymous" blocks unless we are trimming.
static int page_scrubber(void *);
Every 1/10 second, takes a page from the free queue, memsets it to 0's, then puts it on the clear queue.
static void remove_page_from_queue(page_queue *q, vm_page *page)
Removes a given page from the given page queue. No locking.
addr vm_alloc_from_ka_struct(kernel_args *ka, unsigned int size, int lock)
Gets virtual space in the ka using vm_alloc_vspace_from_ka_struct, then uses vm_alloc_ppage_from_kernel_struct to find a physical page to map it to.
static addr vm_alloc_ppage_from_kernel_struct(kernel_args *ka)
Attempts to extend, by one page, one of the phys_alloc_range blocks in the kernel args.
static addr vm_alloc_vspace_from_ka_struct(kernel_args *ka, unsigned int size)
Attempts to find an address range that can be extended to hold size bytes.
vm_page * vm_lookup_page(addr page_num)
Does the math to get vm_page pointer from a page number.
int vm_mark_page_inuse(addr page)
Calls vm_mark_page_range_inuse with len of 1.
int vm_mark_page_range_inuse(addr start_page, addr len)
Sets state to PAGE_STATE_UNUSED for all pages in this range.
vm_page * vm_page_allocate_page(int page_state)
Gets a single page from the clear or free queue (from page_state), fall back to the other.
vm_page * vm_page_allocate_page_run(int page_state, addr len)
Attempts to find a run of pages "len" long that are either free or clear. If found, pulls them from their queues and calls vm_page_set_state_nolock on them
vm_page * vm_page_allocate_specific_page(addr page_num, int page_state)
Finds this page, removes it from the clear or free queue, clears it if necessary and returns. Returns NULL for not found or page in use.
int vm_page_init(kernel_args *ka)
Initializes the free, clear, modified and active queues. Sets up the vm structures.
int vm_page_init2(kernel_args *ka)
Properly maps the vm structures allocated in vm_page_init.
int vm_page_init_postthread(kernel_args *ka)
Creates the page scrubber and the pageout daemon.
addr vm_page_num_pages()
Returns the total number of pages.
addr vm_page_num_free_pages()
Returns count of pages in free and clear queues.
int vm_page_set_state(vm_page *page, int page_state)
Locks, then calls vm_page_set_state_nolock, then unlocks.
static int vm_page_set_state_nolock(vm_page *page, int page_state);
Moves a page from the state that it is in to the state specified, and moves it from the old queue to the new one.