#ifndef _LINUX_MM_H #define _LINUX_MM_H #include #include #ifdef __KERNEL__ #include #include #include #include #include #include extern unsigned long max_mapnr; extern unsigned long num_physpages; extern void * high_memory; extern int page_cluster; /* The inactive_clean lists are per zone. */ extern struct list_head active_list; extern struct list_head inactive_list; #include #include #include /* * 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; /* The address space we belong to. */ unsigned long vm_start; /* Our start address within vm_mm. */ unsigned long vm_end; /* The first byte after our end address within vm_mm. */ /* linked list of VM areas per task, sorted by address */ struct vm_area_struct *vm_next; pgprot_t vm_page_prot; /* Access permissions of this VMA. */ unsigned long vm_flags; /* Flags, listed below. */ rb_node_t vm_rb; /* * 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; /* Function pointers to deal with this struct. */ struct vm_operations_struct * vm_ops; /* Information about our backing store: */ unsigned long vm_pgoff; /* Offset (within vm_file) in PAGE_SIZE units, *not* PAGE_CACHE_SIZE */ struct file * vm_file; /* File we map to (can be NULL). */ unsigned long vm_raend; /* XXX: put full readahead info here. */ void * vm_private_data; /* was vm_pte (shared mem) */ }; /* * vm_flags.. */ #define VM_READ 0x00000001 /* currently active flags */ #define VM_WRITE 0x00000002 #define VM_EXEC 0x00000004 #define VM_SHARED 0x00000008 #define VM_MAYREAD 0x00000010 /* limits for mprotect() etc */ #define VM_MAYWRITE 0x00000020 #define VM_MAYEXEC 0x00000040 #define VM_MAYSHARE 0x00000080 #define VM_GROWSDOWN 0x00000100 /* general info on the segment */ #define VM_GROWSUP 0x00000200 #define VM_SHM 0x00000400 /* shared memory area, don't swap out */ #define VM_DENYWRITE 0x00000800 /* ETXTBSY on write attempts.. */ #define VM_EXECUTABLE 0x00001000 #define VM_LOCKED 0x00002000 #define VM_IO 0x00004000 /* Memory mapped I/O or similar */ /* Used by sys_madvise() */ #define VM_SEQ_READ 0x00008000 /* App will access data sequentially */ #define VM_RAND_READ 0x00010000 /* App will not benefit from clustered reads */ #define VM_DONTCOPY 0x00020000 /* Do not copy this vma on fork */ #define VM_DONTEXPAND 0x00040000 /* Cannot expand with mremap() */ #define VM_RESERVED 0x00080000 /* Don't unmap it from swap_out */ #define VM_STACK_FLAGS 0x00000177 #define VM_READHINTMASK (VM_SEQ_READ | VM_RAND_READ) #define VM_ClearReadHint(v) (v)->vm_flags &= ~VM_READHINTMASK #define VM_NormalReadHint(v) (!((v)->vm_flags & VM_READHINTMASK)) #define VM_SequentialReadHint(v) ((v)->vm_flags & VM_SEQ_READ) #define VM_RandomReadHint(v) ((v)->vm_flags & VM_RAND_READ) /* read ahead limits */ extern int vm_min_readahead; extern int vm_max_readahead; /* * mapping from the currently active vm_flags protection bits (the * low four bits) to a page protection mask.. */ extern pgprot_t protection_map[16]; #define ZPR_MAX_BYTES 256*PAGE_SIZE #define ZPR_NORMAL 0 /* perform zap_page_range request in one walk */ #define ZPR_PARTITION 1 /* partition into a series of smaller operations */ /* * These are the virtual MM functions - opening of an area, closing and * unmapping it (needed to keep files on disk up-to-date etc), pointer * to the functions called when a no-page or a wp-page exception occurs. */ struct vm_operations_struct { void (*open)(struct vm_area_struct * area); void (*close)(struct vm_area_struct * area); struct page * (*nopage)(struct vm_area_struct * area, unsigned long address, int unused); }; /* * 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. * * 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). * * TODO: make this structure smaller, it could be as small as 32 bytes. */ typedef struct page { struct list_head list; /* ->mapping has some page lists. */ struct address_space *mapping; /* The inode (or ...) we belong to. */ unsigned long index; /* Our offset within mapping. */ struct page *next_hash; /* Next page sharing our hash bucket in the pagecache hash table. */ atomic_t count; /* Usage count, see below. */ unsigned long flags; /* atomic flags, some possibly updated asynchronously */ struct list_head lru; /* Pageout list, eg. active_list; protected by pagemap_lru_lock !! */ wait_queue_head_t wait; /* Page locked? Stand in line... */ struct page **pprev_hash; /* Complement to *next_hash. */ struct buffer_head * buffers; /* Buffer maps us to a disk block. */ void *virtual; /* Kernel virtual address (NULL if not kmapped, ie. highmem) */ struct zone_struct *zone; /* Memory zone we are in. */ } mem_map_t; /* * Methods to modify the page usage count. * * What counts for a page usage: * - cache mapping (page->mapping) * - disk mapping (page->buffers) * - page mapped in a task's page tables, each mapping * is counted separately * * Also, many kernel routines increase the page count before a critical * routine so they can be sure the page doesn't go away from under them. */ #define get_page(p) atomic_inc(&(p)->count) #define put_page(p) __free_page(p) #define put_page_testzero(p) atomic_dec_and_test(&(p)->count) #define page_count(p) atomic_read(&(p)->count) #define set_page_count(p,v) atomic_set(&(p)->count, v) /* * Various page->flags bits: * * PG_reserved is set for special pages, which can never be swapped * out. Some of them might not even exist (eg empty_bad_page)... * * Multiple processes may "see" the same page. E.g. for untouched * mappings of /dev/null, all processes see the same page full of * zeroes, and text pages of executables and shared libraries have * only one copy in memory, at most, normally. * * For the non-reserved pages, page->count denotes a reference count. * page->count == 0 means the page is free. * page->count == 1 means the page is used for exactly one purpose * (e.g. a private data page of one process). * * A page may be used for kmalloc() or anyone else who does a * __get_free_page(). In this case the page->count is at least 1, and * all other fields are unused but should be 0 or NULL. The * management of this page is the responsibility of the one who uses * it. * * The other pages (we may call them "process pages") are completely * managed by the Linux memory manager: I/O, buffers, swapping etc. * The following discussion applies only to them. * * A page may belong to an inode's memory mapping. In this case, * page->mapping is the pointer to the inode, and page->index is the * file offset of the page, in units of PAGE_CACHE_SIZE. * * A page may have buffers allocated to it. In this case, * page->buffers is a circular list of these buffer heads. Else, * page->buffers == NULL. * * For pages belonging to inodes, the page->count is the number of * attaches, plus 1 if buffers are allocated to the page, plus one * for the page cache itself. * * All pages belonging to an inode are in these doubly linked lists: * mapping->clean_pages, mapping->dirty_pages and mapping->locked_pages; * using the page->list list_head. These fields are also used for * freelist managemet (when page->count==0). * * There is also a hash table mapping (mapping,index) to the page * in memory if present. The lists for this hash table use the fields * page->next_hash and page->pprev_hash. * * All process pages can do I/O: * - inode pages may need to be read from disk, * - inode pages which have been modified and are MAP_SHARED may need * to be written to disk, * - private pages which have been modified may need to be swapped out * to swap space and (later) to be read back into memory. * During disk I/O, PG_locked is used. This bit is set before I/O * and reset when I/O completes. page->wait is a wait queue of all * tasks waiting for the I/O on this page to complete. * PG_uptodate tells whether the page's contents is valid. * When a read completes, the page becomes uptodate, unless a disk I/O * error happened. * * For choosing which pages to swap out, inode pages carry a * PG_referenced bit, which is set any time the system accesses * that page through the (mapping,index) hash table. This referenced * bit, together with the referenced bit in the page tables, is used * to manipulate page->age and move the page across the active, * inactive_dirty and inactive_clean lists. * * Note that the referenced bit, the page->lru list_head and the * active, inactive_dirty and inactive_clean lists are protected by * the pagemap_lru_lock, and *NOT* by the usual PG_locked bit! * * PG_skip is used on sparc/sparc64 architectures to "skip" certain * parts of the address space. * * PG_error is set to indicate that an I/O error occurred on this page. * * PG_arch_1 is an architecture specific page state bit. The generic * code guarantees that this bit is cleared for a page when it first * is entered into the page cache. * * PG_highmem pages are not permanently mapped into the kernel virtual * address space, they need to be kmapped separately for doing IO on * the pages. The struct page (these bits with information) are always * mapped into kernel address space... */ #define PG_locked 0 /* Page is locked. Don't touch. */ #define PG_error 1 #define PG_referenced 2 #define PG_uptodate 3 #define PG_dirty 4 #define PG_unused 5 #define PG_lru 6 #define PG_active 7 #define PG_slab 8 #define PG_skip 10 #define PG_highmem 11 #define PG_checked 12 /* kill me in 2.5.. */ #define PG_arch_1 13 #define PG_reserved 14 #define PG_launder 15 /* written out by VM pressure.. */ /* Make it prettier to test the above... */ #define UnlockPage(page) unlock_page(page) #define Page_Uptodate(page) test_bit(PG_uptodate, &(page)->flags) #define SetPageUptodate(page) set_bit(PG_uptodate, &(page)->flags) #define ClearPageUptodate(page) clear_bit(PG_uptodate, &(page)->flags) #define PageDirty(page) test_bit(PG_dirty, &(page)->flags) #define SetPageDirty(page) set_bit(PG_dirty, &(page)->flags) #define ClearPageDirty(page) clear_bit(PG_dirty, &(page)->flags) #define PageLocked(page) test_bit(PG_locked, &(page)->flags) #define LockPage(page) set_bit(PG_locked, &(page)->flags) #define TryLockPage(page) test_and_set_bit(PG_locked, &(page)->flags) #define PageChecked(page) test_bit(PG_checked, &(page)->flags) #define SetPageChecked(page) set_bit(PG_checked, &(page)->flags) #define PageLaunder(page) test_bit(PG_launder, &(page)->flags) #define SetPageLaunder(page) set_bit(PG_launder, &(page)->flags) extern void FASTCALL(set_page_dirty(struct page *)); /* * The first mb is necessary to safely close the critical section opened by the * TryLockPage(), the second mb is necessary to enforce ordering between * the clear_bit and the read of the waitqueue (to avoid SMP races with a * parallel wait_on_page). */ #define PageError(page) test_bit(PG_error, &(page)->flags) #define SetPageError(page) set_bit(PG_error, &(page)->flags) #define ClearPageError(page) clear_bit(PG_error, &(page)->flags) #define PageReferenced(page) test_bit(PG_referenced, &(page)->flags) #define SetPageReferenced(page) set_bit(PG_referenced, &(page)->flags) #define ClearPageReferenced(page) clear_bit(PG_referenced, &(page)->flags) #define PageTestandClearReferenced(page) test_and_clear_bit(PG_referenced, &(page)->flags) #define PageSlab(page) test_bit(PG_slab, &(page)->flags) #define PageSetSlab(page) set_bit(PG_slab, &(page)->flags) #define PageClearSlab(page) clear_bit(PG_slab, &(page)->flags) #define PageReserved(page) test_bit(PG_reserved, &(page)->flags) #define PageActive(page) test_bit(PG_active, &(page)->flags) #define SetPageActive(page) set_bit(PG_active, &(page)->flags) #define ClearPageActive(page) clear_bit(PG_active, &(page)->flags) #define PageLRU(page) test_bit(PG_lru, &(page)->flags) #define TestSetPageLRU(page) test_and_set_bit(PG_lru, &(page)->flags) #define TestClearPageLRU(page) test_and_clear_bit(PG_lru, &(page)->flags) #ifdef CONFIG_HIGHMEM #define PageHighMem(page) test_bit(PG_highmem, &(page)->flags) #else #define PageHighMem(page) 0 /* needed to optimize away at compile time */ #endif #define SetPageReserved(page) set_bit(PG_reserved, &(page)->flags) #define ClearPageReserved(page) clear_bit(PG_reserved, &(page)->flags) /* * Error return values for the *_nopage functions */ #define NOPAGE_SIGBUS (NULL) #define NOPAGE_OOM ((struct page *) (-1)) /* The array of struct pages */ extern mem_map_t * mem_map; /* * There is only one page-allocator function, and two main namespaces to * it. The alloc_page*() variants return 'struct page *' and as such * can allocate highmem pages, the *get*page*() variants return * virtual kernel addresses to the allocated page(s). */ extern struct page * FASTCALL(_alloc_pages(unsigned int gfp_mask, unsigned int order)); extern struct page * FASTCALL(__alloc_pages(unsigned int gfp_mask, unsigned int order, zonelist_t *zonelist)); extern struct page * alloc_pages_node(int nid, unsigned int gfp_mask, unsigned int order); static inline struct page * alloc_pages(unsigned int gfp_mask, unsigned int order) { /* * Gets optimized away by the compiler. */ if (order >= MAX_ORDER) return NULL; return _alloc_pages(gfp_mask, order); } #define alloc_page(gfp_mask) alloc_pages(gfp_mask, 0) extern unsigned long FASTCALL(__get_free_pages(unsigned int gfp_mask, unsigned int order)); extern unsigned long FASTCALL(get_zeroed_page(unsigned int gfp_mask)); #define __get_free_page(gfp_mask) \ __get_free_pages((gfp_mask),0) #define __get_dma_pages(gfp_mask, order) \ __get_free_pages((gfp_mask) | GFP_DMA,(order)) /* * The old interface name will be removed in 2.5: */ #define get_free_page get_zeroed_page /* * There is only one 'core' page-freeing function. */ extern void FASTCALL(__free_pages(struct page *page, unsigned int order)); extern void FASTCALL(free_pages(unsigned long addr, unsigned int order)); #define __free_page(page) __free_pages((page), 0) #define free_page(addr) free_pages((addr),0) extern void show_free_areas(void); extern void show_free_areas_node(pg_data_t *pgdat); extern void clear_page_tables(struct mm_struct *, unsigned long, int); extern int fail_writepage(struct page *); struct page * shmem_nopage(struct vm_area_struct * vma, unsigned long address, int unused); struct file *shmem_file_setup(char * name, loff_t size); extern void shmem_lock(struct file * file, int lock); extern int shmem_zero_setup(struct vm_area_struct *); extern void zap_page_range(struct mm_struct *mm, unsigned long address, unsigned long size, int actions); extern int copy_page_range(struct mm_struct *dst, struct mm_struct *src, struct vm_area_struct *vma); extern int remap_page_range(unsigned long from, unsigned long to, unsigned long size, pgprot_t prot); extern int zeromap_page_range(unsigned long from, unsigned long size, pgprot_t prot); extern int vmtruncate(struct inode * inode, loff_t offset); extern pmd_t *FASTCALL(__pmd_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)); extern pte_t *FASTCALL(pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address)); extern int handle_mm_fault(struct mm_struct *mm,struct vm_area_struct *vma, unsigned long address, int write_access); extern int make_pages_present(unsigned long addr, unsigned long end); extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write); extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char *dst, int len); extern int ptrace_writedata(struct task_struct *tsk, char * src, unsigned long dst, int len); extern int ptrace_attach(struct task_struct *tsk); extern int ptrace_detach(struct task_struct *, unsigned int); extern void ptrace_disable(struct task_struct *); extern int ptrace_check_attach(struct task_struct *task, int kill); int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, unsigned long start, int len, int write, int force, struct page **pages, struct vm_area_struct **vmas); /* * On a two-level page table, this ends up being trivial. Thus the * inlining and the symmetry break with pte_alloc() that does all * of this out-of-line. */ static inline pmd_t *pmd_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) { if (pgd_none(*pgd)) return __pmd_alloc(mm, pgd, address); return pmd_offset(pgd, address); } extern int pgt_cache_water[2]; extern int check_pgt_cache(void); extern void free_area_init(unsigned long * zones_size); extern void free_area_init_node(int nid, pg_data_t *pgdat, struct page *pmap, unsigned long * zones_size, unsigned long zone_start_paddr, unsigned long *zholes_size); extern void mem_init(void); extern void show_mem(void); extern void si_meminfo(struct sysinfo * val); extern void swapin_readahead(swp_entry_t); extern struct address_space swapper_space; #define PageSwapCache(page) ((page)->mapping == &swapper_space) static inline int is_page_cache_freeable(struct page * page) { return page_count(page) - !!page->buffers == 1; } extern int can_share_swap_page(struct page *); extern int remove_exclusive_swap_page(struct page *); extern void __free_pte(pte_t); /* mmap.c */ extern void lock_vma_mappings(struct vm_area_struct *); extern void unlock_vma_mappings(struct vm_area_struct *); extern void insert_vm_struct(struct mm_struct *, struct vm_area_struct *); extern void __insert_vm_struct(struct mm_struct *, struct vm_area_struct *); extern void build_mmap_rb(struct mm_struct *); extern void exit_mmap(struct mm_struct *); extern unsigned long get_unmapped_area(struct file *, unsigned long, unsigned long, unsigned long, unsigned long); extern unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, unsigned long len, unsigned long prot, unsigned long flag, unsigned long pgoff); static inline unsigned long do_mmap(struct file *file, unsigned long addr, unsigned long len, unsigned long prot, unsigned long flag, unsigned long offset) { unsigned long ret = -EINVAL; if ((offset + PAGE_ALIGN(len)) < offset) goto out; if (!(offset & ~PAGE_MASK)) ret = do_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT); out: return ret; } extern int do_munmap(struct mm_struct *, unsigned long, size_t); extern unsigned long do_brk(unsigned long, unsigned long); static inline void __vma_unlink(struct mm_struct * mm, struct vm_area_struct * vma, struct vm_area_struct * prev) { prev->vm_next = vma->vm_next; rb_erase(&vma->vm_rb, &mm->mm_rb); if (mm->mmap_cache == vma) mm->mmap_cache = prev; } static inline int can_vma_merge(struct vm_area_struct * vma, unsigned long vm_flags) { if (!vma->vm_file && vma->vm_flags == vm_flags) return 1; else return 0; } struct zone_t; /* filemap.c */ extern void remove_inode_page(struct page *); extern unsigned long page_unuse(struct page *); extern void truncate_inode_pages(struct address_space *, loff_t); /* generic vm_area_ops exported for stackable file systems */ extern int filemap_sync(struct vm_area_struct *, unsigned long, size_t, unsigned int); extern struct page *filemap_nopage(struct vm_area_struct *, unsigned long, int); /* * GFP bitmasks.. */ /* Zone modifiers in GFP_ZONEMASK (see linux/mmzone.h - low four bits) */ #define __GFP_DMA 0x01 #define __GFP_HIGHMEM 0x02 /* Action modifiers - doesn't change the zoning */ #define __GFP_WAIT 0x10 /* Can wait and reschedule? */ #define __GFP_HIGH 0x20 /* Should access emergency pools? */ #define __GFP_IO 0x40 /* Can start low memory physical IO? */ #define __GFP_HIGHIO 0x80 /* Can start high mem physical IO? */ #define __GFP_FS 0x100 /* Can call down to low-level FS? */ #define GFP_NOHIGHIO (__GFP_HIGH | __GFP_WAIT | __GFP_IO) #define GFP_NOIO (__GFP_HIGH | __GFP_WAIT) #define GFP_NOFS (__GFP_HIGH | __GFP_WAIT | __GFP_IO | __GFP_HIGHIO) #define GFP_ATOMIC (__GFP_HIGH) #define GFP_USER ( __GFP_WAIT | __GFP_IO | __GFP_HIGHIO | __GFP_FS) #define GFP_HIGHUSER ( __GFP_WAIT | __GFP_IO | __GFP_HIGHIO | __GFP_FS | __GFP_HIGHMEM) #define GFP_KERNEL (__GFP_HIGH | __GFP_WAIT | __GFP_IO | __GFP_HIGHIO | __GFP_FS) #define GFP_NFS (__GFP_HIGH | __GFP_WAIT | __GFP_IO | __GFP_HIGHIO | __GFP_FS) #define GFP_KSWAPD ( __GFP_WAIT | __GFP_IO | __GFP_HIGHIO | __GFP_FS) /* Flag - indicates that the buffer will be suitable for DMA. Ignored on some platforms, used as appropriate on others */ #define GFP_DMA __GFP_DMA static inline unsigned int pf_gfp_mask(unsigned int gfp_mask) { /* avoid all memory balancing I/O methods if this task cannot block on I/O */ if (current->flags & PF_NOIO) gfp_mask &= ~(__GFP_IO | __GFP_HIGHIO | __GFP_FS); return gfp_mask; } /* vma is the first one with address < vma->vm_end, * and even address < vma->vm_start. Have to extend vma. */ static inline int expand_stack(struct vm_area_struct * vma, unsigned long address) { unsigned long grow; /* * vma->vm_start/vm_end cannot change under us because the caller is required * to hold the mmap_sem in write mode. We need to get the spinlock only * before relocating the vma range ourself. */ address &= PAGE_MASK; spin_lock(&vma->vm_mm->page_table_lock); grow = (vma->vm_start - address) >> PAGE_SHIFT; if (vma->vm_end - address > current->rlim[RLIMIT_STACK].rlim_cur || ((vma->vm_mm->total_vm + grow) << PAGE_SHIFT) > current->rlim[RLIMIT_AS].rlim_cur) { spin_unlock(&vma->vm_mm->page_table_lock); return -ENOMEM; } vma->vm_start = address; vma->vm_pgoff -= grow; vma->vm_mm->total_vm += grow; if (vma->vm_flags & VM_LOCKED) vma->vm_mm->locked_vm += grow; spin_unlock(&vma->vm_mm->page_table_lock); return 0; } /* Look up the first VMA which satisfies addr < vm_end, NULL if none. */ extern struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr); extern struct vm_area_struct * find_vma_prev(struct mm_struct * mm, unsigned long addr, struct vm_area_struct **pprev); /* Look up the first VMA which intersects the interval start_addr..end_addr-1, NULL if none. Assume start_addr < end_addr. */ static inline struct vm_area_struct * find_vma_intersection(struct mm_struct * mm, unsigned long start_addr, unsigned long end_addr) { struct vm_area_struct * vma = find_vma(mm,start_addr); if (vma && end_addr <= vma->vm_start) vma = NULL; return vma; } extern struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr); #endif /* __KERNEL__ */ #endif