docs/develop: More reorganization.
* There is now a 'busses' folder, and the extant USB/SDHCI/Bluetooth/etc. docs now live in it, instead of various other places. * kernel/ports is now kernel/arch, like it is in src/system. SPARC documentation is now in there, too. * VM files (these are rather outdated) are now in kernel/vm. * SCSI ASC info removed, this is easily available online and it doesn't seem to be very relevant.
This commit is contained in:
Augustin Cavalier
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Variables
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extern bool trimming_cycle;
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Determines if we are trimming - if we are nearly out of space
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static page_queue page_free_queue;
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The queue that holds unused (but not cleared) pages
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static page_queue page_clear_queue;
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The queue that holds cleared (0'ed) pages
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static page_queue page_modified_queue;
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The queue that holds altered pages
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static page_queue page_active_queue;
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The queue that holds in use pages that are not altered
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static vm_page *all_pages;
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Every page in the system
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static addr physical_page_offset;
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The first address of real ram
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static unsigned int num_pages;
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Total number of pages in the system
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static spinlock_t page_lock;
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A lock to protect the queues.
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static sem_id modified_pages_available;
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A semaphore to indicate if there are pages that need to be written to disk
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static void clear_page(addr pa);
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Sets all values in this page to 0.
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static vm_page * dequeue_page(page_queue *q)
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Standard queue remove first page; has count; no locking
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void dump_page_stats(int argc, char **argv);
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Dumps counts of each state (active, inactive, busy, not used, modified, free, cleared, wired)
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void dump_free_page_table(int argc, char **argv)
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Not done.
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static void enqueue_page(page_queue *q, vm_page *page)
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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
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static bool is_page_in_phys_range(kernel_args *ka, addr paddr)
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Determines if a physical address is in the physical memory that exists.
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static void move_page_to_queue(page_queue *from_q, page_queue *to_q, vm_page *page)
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Removes the page from the from_q and adds it to the to_q.
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static int pageout_daemon()
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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.
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static int page_scrubber(void *);
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Every 1/10 second, takes a page from the free queue, memsets it to 0's, then puts it on the clear queue.
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static void remove_page_from_queue(page_queue *q, vm_page *page)
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Removes a given page from the given page queue. No locking.
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addr vm_alloc_from_ka_struct(kernel_args *ka, unsigned int size, int lock)
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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.
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static addr vm_alloc_ppage_from_kernel_struct(kernel_args *ka)
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Attempts to extend, by one page, one of the phys_alloc_range blocks in the kernel args.
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static addr vm_alloc_vspace_from_ka_struct(kernel_args *ka, unsigned int size)
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Attempts to find an address range that can be extended to hold size bytes.
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vm_page * vm_lookup_page(addr page_num)
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Does the math to get vm_page pointer from a page number.
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int vm_mark_page_inuse(addr page)
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Calls vm_mark_page_range_inuse with len of 1.
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int vm_mark_page_range_inuse(addr start_page, addr len)
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Sets state to PAGE_STATE_UNUSED for all pages in this range.
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vm_page * vm_page_allocate_page(int page_state)
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Gets a single page from the clear or free queue (from page_state), fall back to the other.
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vm_page * vm_page_allocate_page_run(int page_state, addr len)
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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
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vm_page * vm_page_allocate_specific_page(addr page_num, int page_state)
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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.
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int vm_page_init(kernel_args *ka)
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Initializes the free, clear, modified and active queues. Sets up the vm structures.
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int vm_page_init2(kernel_args *ka)
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Properly maps the vm structures allocated in vm_page_init.
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int vm_page_init_postthread(kernel_args *ka)
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Creates the page scrubber and the pageout daemon.
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addr vm_page_num_pages()
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Returns the total number of pages.
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addr vm_page_num_free_pages()
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Returns count of pages in free and clear queues.
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int vm_page_set_state(vm_page *page, int page_state)
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Locks, then calls vm_page_set_state_nolock, then unlocks.
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static int vm_page_set_state_nolock(vm_page *page, int page_state);
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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.
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